Introduction
============

Chronic kidney disease (CKD), including renal interstitial fibrosis, is a worldwide public health problem causing high morbidity and mortality [@B1]. Renal fibrosis, characterized by fibroblasts activation and extracellular matrix (ECM) deposition, is the terminal manifestation and common irreversible pathway by which CKD progresses to end stage [@B2]. Renal fibrosis results in trauma of renal parenchyma and loss of renal function [@B3]. The incidence of end stage renal disease is rapidly increasing in the prevalence of diabetes and hypertension [@B4]. Clinically, there are few effective therapies for renal fibrosis other than dialysis. Therefore, the development of new strategies for antifibrotic therapy is required.

Interleukin-6 (IL-6) regulates the innate and adaptive immune responses, and it has become a major target for clinical intervention in many proinflammatory conditions [@B5]. IL-6 signaling occurs through two main pathways. In classical pathway, IL-6 binds to the membrane-bound IL-6 receptor (mIL-6R), then recruits signal transducer glycoprotein 130 (gp130) [@B6]; this leads to its homodimerization, which further activates the Janus kinase (JAK)/Tyk tyrosine kinases and leads to the phosphorylation of signal transducer and activator of transcription (STAT) 3. STAT3 is a transcription factor that regulates many downstream target genes [@B7]. In trans-signaling pathway, soluble IL-6R (sIL-6R) detected in body fluids binds to IL-6 with comparable affinity to that of membrane-bound IL-6R. The IL-6/sIL-6R complex also activates membrane gp130, causing subsequent phosphorylation of JAK/STAT3. IL-6 is therefore involved in intracellular signal transduction. It is generally believed that the anti-inflammatory activity of IL-6 is mediated by classical signaling, whereas the proinflammatory property is mediated by the trans-signaling pathway [@B8].

The role of IL-6 in renal fibrosis remains controversial. Elevated plasma levels of IL-6 are commonly observed in CKD patients [@B9]. However, IL-6 knockout (KO) mice showed comparable expression of ECM proteins in the obstructed kidney compared to that in wild-type (WT) mice [@B10]. IL-6 classic signaling can protect renal tissue from overshooting immune responses [@B11]. IL-6 trans-signaling has been shown to play a central role in crescentic nephritis [@B12]. As a specific antagonist of IL-6 trans-signaling in vivo, soluble gp130 is elevated in many pathological conditions [@B13], [@B14]. Gp130 was suggested to be a novel specific antagonist of IL-6 trans-signaling [@B15]. Fc-linked gp130 was produced, and the homodimer was found more effective. Furthermore, recombinant gp130 is currently in clinical trials [@B16]. Therefore, soluble gp130, a specific IL-6 trans-signaling inhibitor that does not affect classic signaling, could be an ideal therapeutic drug for renal inflammation [@B17].

In our previous work, we constructed and purified recombinant Fc-gp130 [@B18]. The Fc-gp130 homodimer was more effective than monomer gp130 at blocking IL-6 trans-signaling, as each functional IL-6/sIL-6R complex associates with two molecules of gp130 to transduce the intracellular downstream signal. In this study, we aimed to determine whether IL-6 trans-signaling is important in the development of renal fibrosis. Our results show that treatment with Fc-gp130, by interfering with IL-6 trans-signaling, attenuates renal fibrosis, therefore indicating that IL-6 trans-signaling blockade could be a promising and novel therapeutic approach for the treatment of renal fibrosis.

Results
=======

Fc-gp130 attenuated renal fibrosis caused by unilateral ureteral occlusion (UUO)
--------------------------------------------------------------------------------

In UUO-ligated mice, the levels of sIL-6R in the kidney (Figure [1](#F1){ref-type="fig"}A), IL-6 and sIL-6R in plasma (Supplementary Figure [S1](#SM0){ref-type="supplementary-material"}A-B) were significantly increased on day 14 after UUO as compared with levels in those receiving sham treatment. In addition, significant increases in IL-6, sIL-6R, mIL-6R, and gp130 in UUO kidneys were also observed by day 14 (Figure [1](#F1){ref-type="fig"}B, Supplementary Figure [S1](#SM0){ref-type="supplementary-material"}C). It is worth noting that sIL-6R levels in the kidney were elevated from day 3 to day 14, suggesting a role for IL-6 trans-signaling in the progression of renal fibrosis (Figure [1](#F1){ref-type="fig"}B). To confirm this, we pre-treated mice with Fc-gp130 to investigate whether specific blockade of IL-6 trans-signaling would protect against renal fibrosis. Interestingly, Fc-gp130 treatment in UUO mice significantly reduced parenchymal loss and tubular atrophy (Figure [1](#F1){ref-type="fig"}C), whereas genetic deletion of IL-6 had no substantial protective effect on UUO-induced fibrosis. Masson\'s staining also revealed that UUO mice showed fibrotic renal tissue with extensive collagen deposition, whereas Fc-gp130 treatment significantly reduced collagen deposition in UUO mice (Figure [1](#F1){ref-type="fig"}D). Next, we analyzed the effect of Fc-gp130 on the production of major components of the ECM, in UUO renal tissue. Immunohistochemical (IHC) staining showed increased accumulation of fibronectin, collagen I, collagen Ⅲ and vimentin following UUO, whereas Fc-gp130-treated mice exhibited reduced ECM content (Figure [1](#F1){ref-type="fig"}E-F, Supplementary Figure [S1](#SM0){ref-type="supplementary-material"}D-E). However, there were no significant differences in renal interstitial fibrosis or deposition of ECM between WT and IL-6 KO mice following UUO injury. Collagen I and fibronectin proteins were also significantly increased in UUO kidneys, and Fc-gp130 treatment significantly reduced collagen I and fibronectin protein levels in the kidneys of UUO mice (Figure [3](#F3){ref-type="fig"}D). Overall, these data suggest that IL-6 trans-signaling promotes renal fibrosis.

Fc-gp130 reduced inflammation in UUO mice
-----------------------------------------

Inflammation is an important driver in the progression of renal fibrosis [@B19], [@B20]. Upon injury, renal tubular cells produce chemokines to recruit immune cells and inflammatory cytokines to activate myofibroblasts to produce ECM [@B21]. Therefore, we next evaluated the impacts of Fc-gp130 on the inflammatory responses in UUO mice. NF-κB p65 activation and nuclear translocation in renal tubular epithelial cells were significantly reduced in Fc-gp130-treated UUO mice compared with that in UUO mice alone (Figure [2](#F2){ref-type="fig"}A, Supplementary Figure [S2](#SM0){ref-type="supplementary-material"}A). IHC analysis also showed that Fc-gp130 inhibited the recruitment of F4/80-positive macrophages (Figure [2](#F2){ref-type="fig"}B), CD4^+^ (Figure [2](#F2){ref-type="fig"}C) and CD8^+^ T cells (Figure [2](#F2){ref-type="fig"}D) in the kidneys of UUO mice. In addition, the mRNA levels of proinflammatory mediator, such as tumor necrosis factor-α (*Tnfa*) (Figure [2](#F2){ref-type="fig"}E), monocyte chemoattraction protein 1*(Mcp1)* (Figure [2](#F2){ref-type="fig"}F), and CXC chemokine ligand 16 *(Cxcl16)* (Figure [2](#F2){ref-type="fig"}G), were also significantly reduced upon Fc-gp130 treatment. The mRNA levels of *Il6* (Figure [2](#F2){ref-type="fig"}H) and *Tgfb* (Figure [2](#F2){ref-type="fig"}I) were not significantly reduced by Fc-gp130. Therefore, blockade of IL-6 trans-signaling with Fc-gp130 attenuated renal inflammation in the UUO mouse model.

Fc-gp130 influenced STAT3 activation in fibroblasts
---------------------------------------------------

Immunostaining of α-smooth muscle actin (α-SMA) was used to investigate fibroblast accumulation. In UUO mice, Fc-gp130 treatment diminished fibroblast accumulation, as evidenced by reduced numbers of α-SMA-positive cells (Figure [3](#F3){ref-type="fig"}A). More specifically, p-STAT3-positive interstitial fibroblasts were abundant in UUO mice but were reduced in number after Fc-gp130 treatment, while p-STAT3-positive tubular epithelial cells were observed in both groups (Figure [3](#F3){ref-type="fig"}B-[1](#F1){ref-type="fig"} and 3B-2). The profibrogenic effect of IL-6 trans-signaling depends on the activation of STAT3 [@B22]. In UUO mice, phosphorylation of STAT3 (p-STAT3) and total STAT3 increased significantly over time, peaking on day 14 after UUO injury (Supplementary Figure [S2](#SM0){ref-type="supplementary-material"}B). Western blotting analysis on day 14 renal lysates also revealed that the ratios of p-STAT3/STAT3 and p-Smad3/Smad3, the levels of α-SMA, fibronectin and collagen I were attenuated, and the ratios of p-Smad1/5/8/Smad1 were increased in Fc-gp130-treated UUO mice compared to those in UUO mice alone; however, the ratios of p-Smad2/Smad2 and p-AKT/AKT, the levels of TGF-β, IL-6 and sIL-6R in Fc-gp130-treated and non-treated UUO mice were not significantly different (Figure [3](#F3){ref-type="fig"}C-D).

In NRK-49F cells, Fc-gp130 attenuated phosphorylation of STAT3 induced by IL-6 plus IL-6R treatment, whereas the p-STAT3 induced by low or high dose of IL-6 alone was not affected (Supplementary Figure [S2](#SM0){ref-type="supplementary-material"}C). We confirmed that Fc-gp130 specifically inhibits IL-6 trans-signaling in renal fibroblasts. IL-6 alone did not alter cell proliferation, but stimulation with IL-6 and IL-6R resulted in an increase in proliferation, while Fc-gp130 treatment reduced it (Figure [4](#F4){ref-type="fig"}A). Cells treated with IL-6 in the absence of sIL6R had a background of phosphorylated STAT3 due to signaling via the membrane bound IL-6R (classical signaling), and IL-6 plus sIL-6R induced phosphorylation of STAT3 (classical and trans-signaling) was significantly suppressed by Fc-gp130 (Figure [4](#F4){ref-type="fig"}B, Supplementary Figure [S2](#SM0){ref-type="supplementary-material"}D-E). This suggests that Fc-gp130 reduced fibroblast proliferation and p-STAT3 activated by IL-6 trans-signaling. We confirmed the result by examining the effect of stattic, an inhibitor of STAT3 activation. The cell proliferation activated by IL-6 trans-signaling was reduced by stattic (Figure [4](#F4){ref-type="fig"}C). Stattic inhibited both IL-6 induced and IL-6 plus IL-6R induced phosphorylation of STAT3 (Figure [4](#F4){ref-type="fig"}D). IL-6 treatment induced a slight increase in p-STAT3 in NRK-49F. IL-6 plus sIL-6R induced a prominent increase in p-STAT3 levels, comparable to that observed in fibroblasts stimulated by transforming growth factor (TGF)-β1 (Figure [4](#F4){ref-type="fig"}E). As expected, TGF-β1-induced increases in p-STAT3 and fibronectin levels were significantly attenuated by Fc-gp130 treatment at 6 and 12 h, and p-Smad3 was reduced by Fc-gp130 at 12 h (Figure [4](#F4){ref-type="fig"}F). Moreover, the levels of p-Smad1/5/8 was increased by Fc-gp130 at 12 h (Figure [4](#F4){ref-type="fig"}G). Therefore, Fc-gp130 attenuated the activation of renal fibroblasts in response to TGF-β1 in vitro. These data support the contribution of IL-6 trans-signaling to fibroblast and STAT3 activation in renal fibrosis.

Fc-gp130 protected against fibrosis after ischemia reperfusion (IR) injury
--------------------------------------------------------------------------

To further confirm the protective effect of Fc-gp130, we constructed a different model of renal fibrosis, the acute kidney injury (AKI)-CKD mouse model, which is more consistent with the clinicopathological process. In AKI-CKD model, the levels of sIL-6R and IL-6 in plasma were significantly increased on day 14 after IR injury (the left renal artery was clamped for 45 min) as compared with levels in those receiving sham control (CON) treatment (Supplementary Figure [S3](#SM0){ref-type="supplementary-material"}A-B). In addition, significant increases in IL-6, sIL-6R, mIL-6R, and gp130 in IR kidneys were also observed by day 14 (Figure [5](#F5){ref-type="fig"}A, Supplementary Figure [S3](#SM0){ref-type="supplementary-material"}C). After IR injury, the concentration of blood urea nitrogen (BUN) and creatinine increased rapidly in one day, then return to normal gradually. The concentrations of BUN and creatinine were significantly decreased in Fc-gp130 treated IR group on day 14 and 28 (Supplementary Figure [S3](#SM0){ref-type="supplementary-material"}D-E). This indicated that Fc-gp130 can accelerate the recovery of IR injured kidneys.

Mice treated with or without Fc-gp130 were exposed to severe renal IR injury and sacrificed at day 42 after injury. Protein levels of fibronectin, α-SMA, p-STAT3, and STAT3 were also significantly increased in IR kidneys, and Fc-gp130 treatment reduced fibronectin, α-SMA, and p-STAT3 levels (Figure [5](#F5){ref-type="fig"}B). IR mouse sections showed extensive renal damage as compared with that in sham control sections. Fc-gp130 treatment reduced lesions in IR mice (Figure [5](#F5){ref-type="fig"}C). On day 42 after IR injury, both glomeruli and interstitial areas between tubules showed significant fibrosis (Figure [5](#F5){ref-type="fig"}D). IR kidneys showed significantly increased α-SMA, fibronectin, collagen Ⅲ and vimentin staining (Figure [5](#F5){ref-type="fig"}E-F, Supplementary Figure [S3](#SM0){ref-type="supplementary-material"}F-G). Fc-gp130-treated IR mice showed significant reductions in ECM deposition and α-SMA content relative to levels in IR mice alone. These results confirmed that Fc-gp130 attenuates chronic renal fibrosis induced by IR in mice.

Discussion
==========

IL-6 trans-signaling, mediated by sIL-6R, has been implicated in various chronic inflammatory conditions: rheumatoid arthritis [@B23], asthma [@B24] and neurodegenerative disorders [@B25], for example. However, its role in renal fibrosis has not yet been elucidated. In this study, we showed that targeting of the IL-6/sIL-6R complex using Fc-gp130 attenuated ECM protein production and inflammation in renal tissues of UUO and AKI-CKD mouse models, suggesting that IL-6 trans-signaling plays an essential role in the development and progression of renal interstitial fibrosis. Therefore, blocking of IL-6 trans-signaling with Fc-gp130 provides a promising new therapeutic strategy for the treatment of renal fibrosis.

Elevated levels of the cytokine IL-6 are linked to renal fibrosis. However, previously, WT and IL-6 KO mice under UUO showed no significant phenotypic differences [@B10], probably because the effects of ablating both the anti-inflammatory classical signaling and proinflammatory trans-signaling pathways may compensate for each other. Similarly, our results indicated that WT and IL-6 KO mice showed no significant changes in renal tissue fibrosis. In the IL-6 KO mice, the absent of pro-inflammatory trans-signaling probably alleviated fibrosis; but the anti-inflammatory of classic IL-6 signaling is also absent in injured renal tissue, and the increase of other inflammatory processes may aggravate renal fibrosis. Specifically neutralizing the pro-inflammatory IL-6 trans-signaling would not compromise other beneficial activities of IL-6 [@B26], [@B27]. In this study, we showed that IL-6 trans-signaling plays a key role in the renal fibrotic process. This is consistent with recent studies in pulmonary and cardiac fibrosis [@B28], [@B29]. Soluble gp130 is the natural inhibitor of IL-6 trans-signaling [@B30]. Using Fc-gp130, an antagonist of IL-6 signaling [@B31], [@B32], we specifically blocked IL-6 trans-signaling without interfering with the classical signaling [@B33], [@B34]. We speculated that this is the cause for better treatment effect of Fc-gp130. In the construction of this molecule, an IgG Fc fragment was added before the N terminus of gp130, producing a homodimer that is more effective than soluble gp130 [@B18]. Fc-fused proteins that have been found clinically efficacious include abatacept [@B35], aflibercept [@B36], and romiplostim [@B37]. Fc-linked gp130 is currently in clinical trials [@B16]. Overall, Fc-gp130 attenuated renal fibrosis in mouse models.

Various cells and molecules are involved in the process of damage repair and reconstruction [@B38]. IL-6 signaling is not the sole mechanism for renal fibrosis. Complex cross-talk in vivo might contribute to the pro- and anti-inflammatory/regenerative properties of IL-6 [@B39]. Cells stained for p-STAT3 were observed in tubular epithelial cells and fibroblasts in obstructed kidneys. Quantitative analysis showed that Fc-gp130 decreased the number of p-STAT3 activated fibroblast, but not the number of p-STAT3-positive tubular epithelial cells. Some studies have implicated STAT3 activation in tubular epithelial cells with the progression of kidney interstitial fibrosis [@B40]. Previous studies have demonstrated that STAT3 signaling in kidney tubular epithelial cells inhibits cells apoptosis and plays an important protective role in limiting kidney dysfunction after acute injury [@B41]-[@B43]. A previous study demonstrated that a receptor-independent gp130/STAT3 agonist prevented renal fibrosis [@B44]. That might be because hyperactive STAT3 plays an important role in protecting the kidneys. Classic signaling can be activated by IL-6 alone in cells with membrane-bound IL-6R and gp130. In contrast, virtually all cells express membrane-bound gp130, and a receptor-independent gp130/STAT3 agonist can activate STAT3 in almost all cells. STAT3 is mechanistically involved in the communication between epithelial cells and fibroblasts [@B45]. Accordingly, activated STAT3 in renal fibroblast is the main driver of renal fibrosis, and tubular epithelial cells probably make a protective contribution.

Activated STAT3 has been found to be an important transcription factor in the pathogenesis of pulmonary and kidney fibrosis [@B46], [@B47]. After ligand-induced dimerization of IL-6R, STAT3 binds to associated JAKs and can be phosphorylated. In addition, a recent study reported that STAT3 could be activated by TGF-β and plays an essential role in UUO-induced renal interstitial fibrosis [@B22]. Therefore, cross-talk between IL-6-STAT3 and TGF-β signaling may exist. The fact that Fc-gp130 treatment affected the phosphorylation of STAT3 further supports this hypothesis. It has also been reported that IL-6-STAT3 signaling enhances the expression of TGF-β1 to promote fibrosis [@B48]. However, in our study, we did not observe any reduction in *Tgfb* mRNA levels in Fc-gp130-treated animals. Furthermore, Fc-gp130 treatment inhibited p-STAT3 levels and ECM production in NRK-49F fibroblasts with sufficient TGF-β1 supplementation in the culture. Fc-gp130 could not only inhibit TGF-β downstream effector p-SMAD3, but upregulate the anti-fibrotic molecules p-SMAD1/5/8, suggesting that Fc-gp130 may interfered with TGF-β signaling through regulation of downstream molecules, independent of an effect on its expression levels. IL-6 trans-signaling plays a major role inflammation [@B49]. Fc-gp130 also affected the activation of NF-κB, another key transcription factor in the development of fibrosis and inflammation. However, the detailed mechanism underlying this cross-talk is unclear, and additional studies are needed to provide further insight.

After injury, inflammatory response and IL-6 signaling are rapidly activated in renal tissue. Due to the fact that the structure and function are affected in damaged and fibrotic kidneys, administered drugs are often not efficiently distributed to the renal target cells [@B50]. Fc-gp130 treatment in advance could confirm the effective concentration in the body, and timely reduce the inflammation. In present study the Fc-gp130 treatment started one week prior. In fact, the disease process of human renal fibrosis can go on a long time. Fc-gp130 treatment thus may have a therapeutic effect after renal injury or fibrosis occurs. However, the opportunity and methods of Fc-gp130 for human kidney disease need further study. There may be side effects when using systemic Fc-gp130 administration. Stability, immunogenicity, and the lack of absorption are limitations of therapeutic proteins [@B51]. Therefore, high concentration of Fc-gp130 is required, which might inhibit both classic and trans-signaling of IL-6 and evoke adverse outcomes [@B52]. Kidney or target cell specific delivery systems might overcome these limitations in fibrosis therapy [@B53]. Subsequently, specific delivery methods could be explored to improve the targeting of Fc-gp130 in the kidney.

In conclusion, the present study found that specifically neutralizing IL-6 trans-signaling attenuated renal fibrosis in UUO and AKI-CKD mouse models. IL-6 trans-signaling may thus represent a critical therapeutic target for managing fibrosis, and Fc-gp130 may be a candidate therapeutic agent for renal fibrosis.

Materials and Methods
=====================

Animals and treatment
---------------------

Animal experiments were approved by the Ethics Committee of Drum Tower Hospital, Medical School of Nanjing University. WT C57BL/6 mice were purchased from the Animal Core Facility of Nanjing Medical University. IL-6 KO mice on a C57BL/6 background were purchased from The Jackson Laboratory (Bar Harbor, ME USA). Since males have better consistency and greater susceptibility to IR than females [@B54], we performed all animal experiments using male mice only. Under specific pathogen-free conditions, male mice (8 weeks old) weighing 20-25 g were housed in standard rodent cages. Mice were divided into four groups for treatment: sham \[phosphate-buffered saline (PBS) treatment and sham surgery\]; Fc-gp130 (Fc-gp130 treatment and sham surgery); UUO/IR (PBS treatment and induction of renal fibrosis); UUO/IR+Fc-gp130 (Fc-gp130 treatment and induction of renal fibrosis). Recombinant mouse Fc-gp130 (Vazyme, Nanjing, China) was used to block IL-6 trans-signaling. Fc-gp130 (20 μg/kg/day) [@B18] or vehicle (PBS) was intraperitoneally injected into mice every other day from one week before the surgery.

UUO model
---------

WT or IL-6 KO mice were anesthetized intraperitoneally with 2% pentobarbital sodium (4 ml/kg) and then placed on the test bench in the prone position. The left ureter was exposed and ligated with sutures at two points near the renal hilum, followed by excision [@B55]. After the incision was closed, mice were given penicillin by intramuscular injection and were allowed to recover in standard rodent cages. Sham-operated control mice underwent abdominal laparotomy without excision of the right ureter. Mice were sacrificed at 3, 7, and 14 days, and renal tissue samples were collected for analysis.

Renal IR model
--------------

WT mice were anesthetized intraperitoneally with 2% pentobarbital sodium (4 ml/kg) and placed on the test bench. After abdominal laparotomy, the left renal pedicle was exposed and clamped for 45 min (ischemia); then, the clamp was removed (reperfusion). After closing the incision, mice were given penicillin by intramuscular injection and were allowed to recover in standard rodent cages. Sham-operated control mice underwent abdominal laparotomy without the clamp. Mice were sacrificed on day 42, and renal tissue samples were collected for analysis. The concentrations of blood serum urea nitrogen (BUN) and creatinine were assessed in duplicated with a commercially available assay kit (BioAssay System, Hayward, CA, USA) according to the instructions.

Enzyme-linked immunosorbent assay (ELISA)
-----------------------------------------

Soluble IL-6R was quantified in plasma and tissue lysates from sham and UUO mouse kidneys using a mouse IL-6R ELISA kit (Raybiotech, Norcross, GA, USA). Plasma IL-6 was quantified using a mouse IL-6 ELISA kit (Raybiotech, Norcross, GA, USA). Renal lysate and plasma samples were diluted in reagent diluent and subjected to ELISA analysis according to the manufacturer\'s protocol.

Antibodies
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Antibodies against Fibronectin (ab2413), Collagen I (ab34710), α-SMA (ab5694), F4/80 (ab6640), CD4 (ab183685), CD8 (ab209775), p-Smad3 (ab52903) and pan Cadherin (ab51034) were from Abcam (Cambridge, UK). Antibodies against p-STAT3 (9145), STAT3 (9139), NF-κB p65 (8242), p-p65 (3033), p-AKT (4060), p-Smad2 (3108), Smad2 (5339), Smad3 (9523), p-Smad1/5/8 (13820), Smad1 (6944), Vimentin (5741), Tubulin (2148), rabbit IgGs (7074) and mouse IgGs (7076) were from Cell Signaling Technology (Danvers, MA, USA). Antibodies against IL-6 (21865), IL-6R (23457), AKT (10176), TGF-β (21898), gp130(21175) and Collagen Ⅲ (22734) were from Proteintech (Rosemont, IL, USA).

Histological analysis
---------------------

Renal tissues were fixed in 4% formaldehyde, dehydrated, embedded, and sectioned at 4 μm thickness. Renal sections were stained with hematoxylin and eosin (H&E) or Masson\'s trichrome (Solarbio Life Sciences, Beijing, China) to evaluate the degree of fibrosis. Sections were observed and scored in a blinded manner. HE slides were scored on a scale from 0 to 4: 0, normal; 1, mild (\<25% of the cortex); 2, moderate (25-50%); 3, severe (50-75%); 4, extensive damage (\>75%) [@B56], [@B57]. The scoring and the positive area of collagen fibers (Masson\'s trichrome, blue) was calculated in 10 bright fields (×200) in the eyepiece of the microscope. Images were acquired using a Leica DM 1000 microscope image system with a digital camera (Wetzlar, Germany).

Immunohistochemistry
--------------------

After dewaxing and rehydration, slides were incubated with 3% H~2~O~2~ for quenching endogenous peroxidase activity and then heated in boiling antigen unmasking solution for antigen retrieval. Slides were blocked with 5% goat serum (Vector Laboratories, UK) for 1 h, then incubated with primary antibody in a humidified chamber at 4℃ overnight. Positive signal was visualized by DAB solution (ZSGB-BIO, Beijing, China). The images were visualized and acquired using the Leica DM 1000 microscope image system. Quantitative evaluation involved the use of Image-Pro Plus 6.0 (Media Cybernetics, Rockville, MD, USA) [@B58]. Positive signals and the number of positive cells in the kidney were quantified in 10 bright fields (×200) in the eyepiece of the microscope.

Cell culture and treatment
--------------------------

Renal fibroblast cell line NRK-49F was from American Type Culture Collection (ATCC, Manassas, USA), and cultured with Dulbecco\'s modified Eagle\'s medium (DMEM, Wisent, Nanjing, China) containing 10% (v/v) fetal bovine serum (FBS, Gibco, Gaithersburg, MD, USA) at 37°C with 5% CO~2~. Fibroblasts were pretreated with serum-free medium for 12 h and then exposed to 5 ng/ml TGF-β1, 50 ng/ml IL-6, 200 ng/ml IL-6R (R&D Systems, MN, USA), or 500 ng/ml Fc-gp130 for 3, 6, or 12 h.

Cell proliferation assay
------------------------

Cell viability was measured at 0, 24, 48, 72 h using a CCK-8 assay kit (Vazyme Biotech, Nanjing, China). Cells were washed and then incubated with a working solution at 37°C for 30 min. Wst-8 in working solution can be reduced to highly soluble formazan (orange product) by various dehydrogenases in the mitochondria. The absorption value of each well, which is proportional to cell viability, was detected at 450 nm using a spectrophotometer system (TECAN, Männedorf, Switzerland).

Western blotting analysis
-------------------------

Renal tissues or cell samples were lysed on ice with lysis buffer containing cocktail proteinase inhibitors and protein phosphatase inhibitors (Thermo Fisher, Rockford, IL, USA). The extracted protein concentrations were quantified via BCA assay, mixed with loading buffer and boiled. Proteins were resolved on 10% SDS-PAGE in running buffer, transferred to polyvinylidene difluoride (PVDF) membranes (Bio-Rad, Hercules, USA), blocked with blocking buffer, and blotted with the primary antibodies at 4℃ overnight. Blots were washed and followed by incubation with secondary antibodies. After washing three times with PBST, signals were detected by chemiluminescence (Tanon, Shanghai, China), and visualized by ChemiScope 3300 Mini Imaging System (CLiNX, Shanghai, China). The western blot data was quantified by IMAGE J.

Real-time quantitative polymerase chain reaction (RT-qPCR)
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Total RNA samples were extracted with TRIzol reagent (Invitrogen, Carlsbad, USA). Reverse transcription were performed using the PrimeScript RT Reagent Kit (Takara, Otsu, Japan). PCR reaction systems were performed using AceQ qPCR SYBR Green Master Mix (Vazyme). Reactions were run on a StepOne Plus (Applied Biosystems, Foster City, USA). The mRNA levels were normalized to that of actin mRNA and calculated using the 2^-△△CT^ method. The specific primers used for analysis were as follows: MCP-1 forward, 5\'-TTAAAAACCTGGATCGGAACCAA-3\'; MCP-1 reverse, 5\'-GCATTAGCTTCAGATTTACGGGT-3\'; TNFα forward, 5\'-ACCCTCACACTCAGATCATCTTC-3\'; TNFα reverse, 5\'-TGGTGGTTTGCTACGACGT-3\'; CXCL16 forward, 5\'-AGTGTCGCTGGAAGTTGTTCT-3\'; CXCL16 reverse, 5\'-GTTCCACACTCTTTGCGCTC-3\'; IL-6 forward, ACAAAGCCAGAGTCCTTCAGAGA; IL-6 reverse, CTGTTAGGAGAGCATTGGAAATTG; TGF-β forward, CGGTGCTCGCTTTGTA; TGF-β reverse, GCCACTCAGGCGTATC; Actin forward, 5\'-TAAAGACCTCTATGCCAACACAGT-3\'; Actin reverse, 5\'-CACGATGGAGGGGCCGGACTCATC-3\'.

Statistical analysis
--------------------

All data are expressed as mean ± SD. Statistical analysis involving two groups was performed by means of Student\'s t test. Multiple group comparisons were performed by one-way ANOVA statistical test. All data were processed with IBM SPSS Statistics 21 and GraphPad Prism 6. A *p-*value \< 0.05 was considered statistically significant.

Supplementary Material {#SM0}
======================

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Supplementary figures.

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Click here for additional data file.

This work was supported by grants from the National Natural Science Foundation of China (81772710, 81502203), the Project of Invigorating Health Care through Science, Technology and Education Jiangsu Provincial Key Medical Discipline (ZDXKB2016014) and Key Medical Talents (QNRC2016015), the General Financial Grant from the China Postdoctoral Foundation (2018M640477, 2017M621729), Nanjing Health Distinguished Youth Fund (JQX15006), Nanjing Science and Technology Project (201715025, QRX17139), the Postdoctoral Research Foundation of Jiangsu Province (1701021B, 2018Z079).

Contributions
=============

WC and XZ designed the study. HY, TW, WC and HY performed animal experiments. WC and YF performed histological analysis and IHC. WC and BJ performed WB and RT-qPCR. WC performed cell experiments. WC and XZ analyzed data. WC, HZ and XZ wrot the manuscript. XZ and HG supervised research.

UUO

:   unilateral ureteral occlusion

IL-6

:   interleukin-6

sIL-6R

:   soluble IL-6 receptor

gp130

:   glycoprotein 130

STAT3

:   signal transducer and activator of transcription 3

ECM

:   extracellular matrix

α-SMA

:   α-smooth muscle actin

TGF-β1

:   transforming growth factor-β1

TNFα

:   tumor necrosis factor-α

MCP-1

:   monocyte chemoattraction protein 1

CXCL16

:   CXC chemokine ligand 16

AKI

:   acute kidney injury

CKD

:   chronic kidney disease

IR

:   ischemia reperfusion

![**Renal fibrosis was reduced in mice with unilateral ureteral obstruction (UUO) treated with Fc-gp130. (A)** ELISA of sIL-6R in renal lysates from mice on day 14 after UUO and sham control (CON) surgery. **(B)** Western blotting analysis of IL-6, sIL-6R and tubulin in renal lysates on days 3, 7, and 14 after UUO. **(C)** Samples from WT mice pretreated with or without Fc-gp130 and IL-6 KO C57BL/6 mice were collected on day 14 after UUO or CON surgery. Renal sections were stained with H&E for visualizing parenchymal loss and tubular atrophy, and renal lesions were scored. **(D)** Masson trichrome staining for tubulointerstitial fibrosis and collagen deposition (blue), and quantitative analysis of fibrotic area.**(E-F)** Immunohistochemistry and quantitative analysis of collagen I (E) and fibronectin (F) content in renal tissue. Scale bar, 50 μm. Data are means ± SD, *n* = 6 per group; ns, not significant, \**p* \< 0.05, \*\**p* \< 0.01, \*\*\**p* \< 0.001. Similar results from three independent experiments are shown.](thnov09p3980g001){#F1}

![**Renal inflammatory responses were reduced in UUO mice treated with Fc-gp130. (A-D)** Samples from mice pretreated with or without Fc-gp130 were collected on day 7 after UUO or sham control (CON) surgery. Immunohistochemistry of NF-κB p65 and quantitative analysis of p65 nuclear localization (A). Immunohistochemistry of F4/80 (B), CD4 (C), and CD8 (D) and positive cells in renal tissue. **(E-I)** RT-qPCR analysis of mRNA levels of *Tnfa* (E), *Mcp1* (F), *Cxcl16* (G), *Il6* (H), and *Tgfb* (I). Data are means ± SD, *n* = 6 pre group; ns, not significant, \**p* \< 0.05, \*\* *p* \< 0.01, \*\*\* *p* \< 0.001. Similar results from three independent experiments are shown.](thnov09p3980g002){#F2}

![**Fc-gp130 suppressed STAT3 activation in renal tissues of UUO mice. (A)** Immunohistochemistry and quantitative analysis of α-SMA content in renal tissue. **(B)** Immunohistochemistry of p-STAT3 (brown) in fibroblasts (α-SMA, red) from renal sections. Red arrows denote p-STAT3 and α-SMA co-positive interstitial cells, black arrows denote p-STAT3 positive epithelial cells (B-1), and quantitative analysis of positive cells (B-2). Scale bar, 50 μm. Data are means ± SD, *n* = 6 pre group; \**p* \< 0.05, \*\* *p* \< 0.01. **(C-D)** Renal tissue samples were collected on day 14 after UUO and Fc-gp130 treatment. Western blotting analysis of phosphorylated (p)-STAT3, total STAT3, p-Smad3, Smad3, p-Smad2, Smad2, p-AKT, AKT, TGF-β, IL-6, sIL-6R, α-SMA (C), Fibronectin, Collagen I, p-Smad1/5/8, Smad1 and tubulin in renal lysates (D). Each experiment was performed at least in triplicate.](thnov09p3980g003){#F3}

![**Fc-gp130 inhibited proliferation of fibroblasts by suppressing STAT3 activation. (A-B)** NRK-49F cells were incubated with vehicle (CON), IL-6 (50 ng/ml), IL-6R (200 ng/ml) and Fc-gp130 (500 ng/ml) for the indicated durations. Changes of cell proliferation (A), and western blotting analysis of p-STAT3, STAT3 and tubulin (B). **(C-D)** NRK-49F cells were incubated with vehicle (CON), IL-6 (50 ng/ml), IL-6R (200 ng/ml) and Stattic (2 μM) for the indicated plans and durations. Changes of cell proliferation (C), and western blotting analysis of p-STAT3, STAT3 and tubulin at 12h (D). Data are means ± SD, 6 duplicate samples in each group for (A) and (C); \*p \< 0.05, \*\* *p* \< 0.01. **(E)** NRK-49F cells were incubated with vehicle (CON), TGF-β1 (5 ng/ml), IL-6 (50 ng/ml) plus IL-6R (200 ng/ml), or IL-6 only for the indicated durations. Western blotting analysis of p-STAT3, STAT3 and tubulin.**(F-G)** NRK-49F cells were incubated with vehicle (CON), TGF-β1 (5 ng/ml) only, or TGF-β1 (5 ng/ml) plus Fc-gp130 (500 ng/ml) for 3, 6, 12 h. Western blotting analysis of fibronectin, p-STAT3, total STAT3, p-Smad3, total Smad3 (F), p-Smad1/5/8, total Smad1 and tubulin (G). Each experiment was performed at least in triplicate.](thnov09p3980g004){#F4}

![**Renal fibrosis was reduced in AKI-CKD mice treated with Fc-gp130. (A)** Renal tissue samples were collected on day 14 after renal ischemia reperfusion (IR) or sham control (CON) surgery. Western blotting analysis of IL-6, sIL-6R and tubulin in renal lysates. **(B)** Mice were treated with vehicle (saline) or Fc-gp130, and samples were collected on day 42 after renal IR or sham control surgery. Western blotting analysis of fibronectin, α-SMA, p-STAT3, STAT3 and tubulin in renal lysates.**(C-F)** Renal sections were stained with H&E for visualizing parenchymal loss and tubular atrophy, and renal lesions were scored (C). Masson trichrome staining for tubulointerstitial fibrosis and collagen deposition (blue), and quantitative analysis of fibrotic area (D). Immunohistochemistry and quantitative analysis of α-SMA (E) and fibronectin (F) content. Scale bar, 50 μm. Data are means ± SD, *n* = 6 per group; ns, not significant, \**p* \< 0.05. Similar results from three independent experiments are shown.](thnov09p3980g005){#F5}

[^1]: ^\*^These authors contributed equally to this study.

[^2]: Competing Interests: The authors have declared that no competing interest exists.


The 2018 Mens’ World Cup is in the books, with the French men’s national team prevailing over their upset-minded Croatian counterparts by the score of 4-2, in a game that featured enough flashes of brilliance to serve as a fitting capper to a tournament that routinely offered soccer fans riveting moments to savor.

Of course, alongside the thrilling matches themselves, this World Cup was suffused with a heavy dose of geopolitical drama — a perhaps inescapable condition in international sports.

As my colleague Luke Barnes reported, this World Cup ended up being something of a soft power coup for Russia’s president Vladimir Putin. Throughout the tourney, the cameras captured what looked to all the world to be a welcoming, efficiently-run nation, free of discord. Traveling fans got a healthy dose of fun and spectacle, behind which Russia’s many problems were obscured, with nary a discouraging word to be heard on matters such as the Russian government’s stealth decision to raise the retirement age or the fatal cloak-and-dagger dance going on between Russia and the United Kingdom.

Next year, the world’s finest women soccer players will meet in France to contest their own title. But not long after that, attention will swing back to the men once more, who in 2022 will compete again, this time in the Arab Gulf nation of Qatar. Those hoping for a competition with fewer geopolitical implications are going to be disappointed — and that’s the optimistic take. For while Russia’s Cup took place against the backdrop of Great Power interplay, Qatar’s relative obscurity on the grand political stage will nevertheless present participants and fans with a very grave and unsettling moral disorder to ponder.

It has been reported that when President Bill Clinton, who served as the honorary chairman of the United States’ own bid to win the 2022 World Cup, found out that he had lost out to Qatar, he returned to his Zurich hotel room and “reached for an ornament on a table,” which he then “threw…at a wall mirror in a fit of rage, shattering the glass.”

Clinton has since denied having participated in this fit of minor vandalism, but you almost couldn’t fault him for his reaction. Qatar’s win was, to say the least, a shock. While Qatar has taken recent strides in developing a local league system, for which it is actively recruiting talent from Africa, the nation can’t be said to have a particularly noteworthy football culture: Its men’s team has never qualified for a World Cup, a FIFA Confederations Cup, or an Olympic Games. In fact, its most significant accomplishment is being a three-time winner of the minor Arab Gulf League tournament. The automatic qualification Qatar will receive as hosts will be the first time it has been within sniffing distance of a major trophy.

Qatar is also a rather inhospitable place for the world’s most celebrated soccer tournament. Stiflingly humid throughout the warmer months, its summertime temperatures reliably soar into the triple-digits, a factor which forced FIFA to move the tournament’s kick-off to late November. That move that will bring chaos to most of the world’s major soccer leagues, whose top players will have to take leave from their club teams in the middle of their seasons to compete for their national teams — in addition to taking time to recover from the World Cup’s unforgiving schedule.

The social climate of the Arab nation may be as jarring for both visiting, free-spirited soccer fans and the corporate brands that typically drape themselves over whatever empty space upon which a television camera might alight. Qatar operates under strict, Wahhabi-influenced Sharia law which attaches harsh criminal penalties to such things as alcohol consumption (forbidden in all but a few venues) and anything that might be termed an “illicit” sexual practice. The pressure of welcoming the world’s soccer fans have forced Qataris to relent somewhat on policing activities that might otherwise earn Muslims some very harsh penalties. For instance, there will be FIFA “fan zones” where alcohol consumption is permitted, but soccer fans who might otherwise be accustomed to big, open cities in which to gambol and explore are going to have to adjust to life inside a theocratic autocracy.

In 2011, Qatar played host to the Asian Cup final between Japan and Australia at Khalifa International Stadium in Doha, and as trial runs for staging a major soccer tournament goes, this did not go well. As Al Jazeera’s Paul Rhys reported, thousands of fans were turned away despite having tickets after police imposed a lockout. According to the report, a complete lack of management at the stadium’s points of entry seemed to be the cause of the chaos. Per Rhys:

The official attendance of the final was 37,174, but other fans said their tickets had not been checked properly as they entered the 40,000 capacity arena. “When we got to the ground not one person checked our tickets we were just ushered through,” said one Australia fan. “No bar code scanners like at the other matches I attended (they were all broken). We didn’t even have our tickets looked at – we didn’t have to present them to gate staff, grand stand staff – no one. So how they got an ‘official attendance’ is beyond me. Thousands more fans were stopped from leaving after Japan beat Australia 1-0 in extra time, being held within the perimeter of the stadium behind locked fences due to a fireworks display that was being launched outside the ground.

What then, did Qatar bring to the table? The short answer: a mountain of petro-chemical wealth. The nation consistently is ranked as having the world’s highest per-capita income, as measured by the International Monetary Fund. And in FIFA, the sport’s global governing body, Qatar found a partner more than willing to court a little corruption. Over the years, FIFA has been consistently exposed as a gang of blackguards masquerading as an international sporting concern. In his 2014 book, Omertà, Scottish investigative reporter Andrew Jennings — a longtime and fastidious chronicler of FIFA’s delinquency — wrote that “the leadership of FIFA…tick all the boxes defining an Organised Crime Syndicate.”

So it was hardly surprising when, in 2014, the Sunday Times reported that Qatar’s successful bid hinged on $5 million in bribes paid to various officials. As the BBC summarized for those without access to the Times’ pay-walled report:

The Sunday Times has obtained millions of secret documents – emails, letters and bank transfers – which it alleges are proof that the disgraced Qatari football official Mohamed Bin Hammam made payments totalling US$5m (£3m) to football officials in return for their support for the Qatar bid. […] The documents also show how Bin Hammam was making payments directly to football officials in Africa to allegedly buy their support for Qatar in the contest.

FIFA VP Michael Piatini made all the appropriate noises in the wake of the report, assuring everyone that “if corruption is proven, [FIFA] will take a new vote.” But as you may have noted, Qatar is still sitting pretty as the tourney’s next host. Meanwhile, it’s probably worth noting that only 22 members of FIFA’s 24-person executive committee were available to offer rulings on the host bids because, as Grantland’s Brian Phillips noted, two members had been “caught trying to sell their votes to undercover journalists.”

Criminal geniuses, these are not. But the limited accountability under which FIFA has traditionally operated has meant that officials have mastered the delicate art of promising reforms that never really quite arrive, and looking the other way in the meantime.

But there’s something else about Qatar’s World Cup that may not be so easily dismissed. At some point during the bidding process, the Qatari officials would have had to account for the means by which they’d create the world-class soccer infrastructure that the tournament demands. They would have had to lay out their core competency in areas like stadium construction. And while we can’t precisely account for what FIFA may have been told then, we absolutely can explain how Qatar has gone about building the World Cup of their dreams: A forced-labor arrangement that resembles a modern form of slavery.

Qatar’s labor practices include something called the Kafala system, an arrangement that exists in different forms throughout the Arab peninsula. The system is meant to monitor and manage migrant workers, who come to places like Qatar from poorer nations (The Guardian has reported that work in advance of the World Cup has brought an influx of migrant laborers from Nepal and India). If you’ve ever thrilled at the sight of Dubai’s futuristic cityscape, it’s all built on very similar labor practices in the neighboring United Arab Emirates.

To find work in Qatar, migrants must first find an employer to sponsor them, to whom they are subsequently bound. Migrant workers are thus shut out of any means to negotiate for better pay or conditions or seek better wages with a different sponsor. What’s more, Qatar’s exit visa system means that migrants cannot leave Qatar without their passports and paperwork, all of which their sponsors control. Which means that those who find themselves working in harsh conditions could find themselves trapped within Qatar’s borders, with no choice but to maintain their indentured servitude.

Naturally, the Qataris themselves do not have to suffer under these sorts of labor practices. This has bred, within Qatari society, a pernicious class divide, with one privileged group of people inventing and enforcing draconian rules over an underclass of non-citizens of different ethnicities and national origins. As such, Qataris have little understanding and empathy for the people who literally get crushed under the marble stones that pave their 5-star hotel lobbies.

Nevertheless, as you might imagine, these labor practices frequently run afoul of international human rights organizations. As Human Rights Watch’s Nicholas McGeehan told CNN in May of 2013:

“It is the same old story. The Kafala system, the confiscation of passports, the illegal charging of exorbitant agent fees, the inability for workers to access the courts for redress. “Qatar has an exit visa system so you cannot leave the country without the sponsor’s say. You have a system where workers are trapped in the country and the same old abuses rear their head. Unpaid wages, wages held in arrears. It keeps workers credibly vulnerable,” he added.

It’s important to note that none of this is specific to the men’s World Cup — these labor practices have long been a Qatari tradition, the means by which they’ve built their international airport, the fancy Doha digs enjoyed by all manner of international conferences, and the international campuses of many prominent American universities. In short, there’s a long list of institutions that are implicated in Qatar’s horrific labor practices. But the men’s World Cup has brought new light and attention to the matter, and in recent years, Qatar has faced increasing scrutiny.

In 2014, the International Trade Union Confederation (ITUC) released a scathing report that characterized Qatar as “a country without a conscience.” As Deadspin’s Tom Ley reported, the ITUC bore witness to a parade of horrors, many of which were provided by first-person accounts from the migrant workers themselves. (One read: “I went on site this morning at 5:00 a.m. and there was blood everywhere. I don’t know what happened, but it was covered up with no report. When I reported this, I was told that if I didn’t stop complaining, I would be dismissed.”)

As Ley noted at the time: “The ITUC estimates that 4,000 migrant workers will die before the 2022 World Cup, an estimate based on mortality trends previously reported by embassies within the country.”

The ITUC’s findings did not go over well in Qatar, but the government nevertheless commissioned international law firm DLA Piper to take on a fact-finding mission. As the Guardian reported in May of 2014:

The report by the international law firm DLA Piper calls for changes to the much-criticised kafala system that ties workers to their employers. It also contains the Qatari government’s own figure on the numbers of migrants who have died on its soil: 964 from Nepal, India and Bangladesh in 2012 and 2013. In all, 246 died from “sudden cardiac death” in 2012, the report said, 35 died in falls and 28 committed suicide. The number of deaths resulting from work-related injuries was low.

DLA Piper’s report made 62 recommendations for reform. But none of these appear to have been taken up with much zeal. In November of 2014, The Guardian’s Pete Pattison reported that “thousands of migrant labourers from North Korea” had been found working on construction sites in Qatar, their presence facilitated by an arrangement between those two nations that amounted to “state-sponsored slavery.” Per Pattison:

According to testimonies from workers and defectors, labourers from the reclusive state said they receive almost no salaries in person while in the Gulf emirate during the three years they typically spend there. They work in the expectation they will collect their earnings when they return to North Korea, but according to a series of testimonies from defectors and experts, workers receive as little as 10% of their salaries when they go home, and some may receive nothing. One North Korean worker at a construction site in central Doha told the Guardian: “We are here to earn foreign currency for our nation.”

The following May, German television journalists, in a broad report on FIFA’s corruption, further documented the harsh working conditions in which Qatar’s migrant workforce labored. As Deadspin’s Diana Moskovitz reported, “Journalists working on the project said they were detained, had all their material erased, and their equipment demolished while shooting in Qatar.”

It’s no wonder that in October of 2015, the ITUC again condemned the nation for allowing “modern slavery” to thrive, with ITUC General Secretary Sharan Burrow declaring, “Promises of reform have been used as a smokescreen to draw in companies and governments to do business in Qatar as the Gulf state rolls out massive infrastructure developments to host the 2022 FIFA World Cup.”

In March of 2016, Amnesty International joined the fray in earnest with an 80-page report titled, “The ugly side of the beautiful game: Labor exploitation on a Qatar World Cup venue.” Drawing on first person accounts from more than 200 migrant workers in Qatar, Amnesty International found the host nation playing the same old game. As CNN reported:

The abuses found include: workers living in “squalid and cramped accommodation”; employers confiscating workers passports; workers being threatened for complaining about working conditions; workers having to pay as much as $4,300 to recruiters in their home country to get a job in Qatar, along with some not being paid for months.

Qatari officials stridently disputed Amnesty’s report, complaining that their study was not representative of the entire migrant workforce and insisting that many of the accounts pre-dated reforms. In a statement to CNN, the nation’s Supreme Committee for Delivery & Legacy wrote: “We have always maintained this World Cup will act as a catalyst for change — it will not be built on the back of exploited workers.”

It’s not clear that the Committee understood that offering up such a declaration was insufficient in ameliorating abuses which had already taken place. For Amnesty International General Secretary Salil Shetty’s part, it was too little, too late. “The abuse of migrant workers is a stain on the conscience of world football,” said Shetty.

It’s not clear that significant change has occurred in Qatar in recent months. In March of 2017, the United Nations’ International Labour Organization (ILO) gave Qatar a November 2017 deadline “to implement new labor reforms designed to end abuse of migrant workers or potentially face an investigation by an international labor watchdog in the lead up to hosting the 2022 World Cup.” In June of this year, Human Rights Watch offered Qatar some praise for some mild domestic labor reforms, but persisted in their calls for the plight of migrant workers to be addressed as well as recommending that the Kafala system be “ended…in full.”

Throughout years of scrutiny, various officials have threatened to review — and potentially revoke — Qatar’s bid. None of these threats have seemed particularly toothsome, and indeed, the run-up to Qatar’s first turn as host to a major sports event continues apace. Those who might have the power to bring about change in Qatar or speed a process of finding a more appropriate host for the Cup — such as the major international soccer federations or the corporate brands that typically lend their imprimatur to such events — so far have muted their voices. It’s very possible that when all is said and done, the players themselves will be called upon to answer for the abuses that built the Qatari World Cup.

Meanwhile, what’s being built in Qatar to facilitate the grandest contest in men’s soccer looks breathtakingly beautiful — architectural feats that hold the promise of an incredible, science-fiction world awaiting us in the near future. But seen under the brightest lights, shot in high-definition, one might do well to remember that they were all paid for by the blood of the poor.

[Dorothy Parvaz contributed to this report.]


The development team behind altcoin Bitcoin Private (BTCP) has confirmed the creation of 2.04 million units of BTCP “that were never intended to exist on the blockchain,” according to an official statement published Dec. 24.

On Dec. 23, digital assets analytics website Coin Metrics published a report revealing that during the import of Bitcoin (BTC) chain data, an additional 2.04 million units of altcoin BTCP — about $3.9 million at press time — were secretly minted. Per the project’s white paper, the total supply of BTCP is equal to around 20.4 million coins, while the secretly premined BTCP brought “the initial supply to 22.6 million.”

The BTCP core team says in today’s statement that upon receiving the reports, they “immediately launched an investigation to ascertain whether or not the alleged findings of an additional amount of BTCP coins were true.” After performing an internal audit, the team officially says that Coin Metrics’ findings were “mathematically accurate.” The team added:

“However, at this time, the source, purpose, and recipient of this exploit is currently unknown to the Bitcoin Private Contribution Team.”

The statement further cites the timeline of events regarding the issue, unveiling that ultimately there was a bounty posted for a specific issue, which was subsequently accepted by a developer, who then became a BTCP developer and was “promoted to a contributor on GitHub, allowing him to merge pull requests.”

That developer reportedly then completed the issue, merged their own code, and received their reward. The BTCP team further discovered that one line missing in the code “allow[ed] the fork mine to be exploited due to the nodes not properly verifying the falsified fork blocks.” Once the bounty was collected, the developer left the BTCP project.

After that, the threat actor reportedly exploited the bug, creating over 2 million coins during the publicly announced fork mine. The statement reads:

“As the code was open source, and the fork-mine was announced on Twitter, anyone with sufficient blockchain development knowledge could have exploited it.”

The BTCP team further notes it is not clear whether those coins were transferred to an exchange or used or stored elsewhere. However, the team’s statement concludes:

“this particular exploit could only be taken advantage of during the fork mine, which already occurred earlier this year. Therefore, it is impossible for this particular bug exploit to occur again, nor can it be further exploited.”

The BTCP team also stated in the announcement that they had “no prior knowledge” of the incident before Coin Metrics’ report was released to the public.

At the end of the statement, the BTCP team writes that they have contacted major crypto exchange HitBTC about the situation. HitBTC has not responded to Cointelegraph’s request for comments by press time.

At press time, BTCP is trading at around $1.97, down close to 7 percent over the last 24 hours, according to CoinMarketCap.

In September, Bitcoin Core released an update following the recent detection of a vulnerability in the software. The vulnerability could reportedly have caused a crash of older versions of Bitcoin Core if they attempted processing a block transaction that tries to spend the same amount twice.


---
abstract: 'Thermal conductivity of a model glass-forming system in the liquid and glass states is studied using extensive numerical simulations. We show that near the glass transition temperture, where the structural relaxation time becomes very long, the measured thermal conductivity decreases with increasing age. Secondly the thermal conductivity of the disordered solid obtained at low temperatures depends on the cooling rate with which it was prepared, with lower cooling rates leading to lower thermal conductivity. Our analysis links this decrease of the thermal conductivity with increased exploration of lower-energy inherent structures of the underlying potential energy landscape. Further we show that the lowering of conductivity for lower-energy inherent structures is related to the high frequency harmonic modes associated with the inherent structure being less extended.'
author:
- Pranab Jyoti Bhuyan
- Rituparno Mandal
- Pinaki Chaudhuri
- Abhishek Dhar
- Chandan Dasgupta
title: 'Thermal Conductivity of Glass-Forming Liquids'
---

[*Introduction*]{} – Thermal conductivity is an important material property with wide ranging applications and understanding the mechanism of heat transport in different materials is crucial from both theoretical and applied perspectives. It is well known that crystalline materials transport heat more efficiently than glassy and disordered materials, for which the thermal conductivity ($\kappa$) can be orders of magnitude smaller [@Cahill:88; @Pohl:71].

A well-studied feature of glassy systems is the temperature $(T)$-dependence of their thermal conductivity, which is very distinct from crystals. One typically finds $\kappa \sim T^2$ at very low temperatures, followed by a pronounced plateau and then an eventual gradual increase with temperature. The low temperature features are expected to be of quantum-menchanical origin and a range of mechanisms have been proposed to explain them [@Anderson:72; @Buchenau:92; @Clare:87]. One scenario relates the plateaue to the presence of excess modes, the so-called [*boson peak*]{}, in the low-frequency regime of the vibrational spectrum of glasses [@Lubchenko:03; @schirmacher:2006; @Nagel:10], which has thereafter been connected with the presence of elastic heterogeneities in such materials [@Maruzzo:2013; @Barrat:16].

More recently, a number of studies have looked at higher temperatures where classical physics dominates. This includes regimes much below the glass transition temperature where the system gets stuck in the basin of a low-energy [*inherent structure*]{} (IS) (local minimum of the potential energy), as well as intermediate temperatures where the system evolves slowly while undergoing transitions between different basins. In the former case the system can be effectively described by a disordered harmonic model obtained by expanding the many-body potential about the minimum. Heat transport is then related to the diffusivity associated with the normal modes of the harmonic solid [@Allen:89; @Allen:93]. In the context of the jamming transition, the change in the form of the diffusivity in a soft-sphere packing was studied in [@Nagel:09; @Nagel:10; @wyart:10], and a crossover was observed near the boson-peak frequency as the transition was approached. In [@Barrat:13], it was shown that the introduction of polydispersity leads to an amorphisation transition, whereby the thermal conductivity of the system decreases considerably.

So far the question as to whether thermal transport in glasses depends upon the age of the material, or on the cooling rate used in its preparation has not been explored. Here we address this question. It is well-known that the material properties of glasses depend on their age and history of preparation, e.g. the cooling rate by which they were quenched from a fluid phase [@Kob:97; @Binder:96; @glassbook]. This dependence on the history can be seen, for example, in the transient response of glasses to applied shear [@Shi:06; @Moorcroft:11; @Chaudhuri:16]. Surprisingly, in the case of thermal transport, there is not much systematic study. Using extensive numerical simulations of a model structural glass former, we show that the thermal conductivity does depend on the age of the glass and on the rate of cooling during preparation. Further, we demonstrate that the decrease of thermal conductivity in glasses with growing age or slower cooling rate is linked to the exploration of ISs with lower energy. By calculating the participation ratio of the normal modes associated with different ISs, we see that the decrease in $\kappa$ is related to an increase in the degree of localization of high frequency vibrational modes.

Another puzzling issue that we address relates to the question of whether the thermal conductivity of the disordered harmonic system that describes the dynamics of small displacements from an IS is infinite. Rayleigh scattering of low frequency ($\omega$) phonons is expected to lead to mean free paths $\ell \sim 1/\omega^4$ [@ziman], which can cause a divergence of $\kappa$ and this is seen in some recent studies [@Nagel:09; @kundu:10; @chaudhuri:10]. In our study we compute the thermal conductivity $\kappa$ of a glass former using three numerical methods (see below), all of which indicate a finite conductivity as $T \to 0$, where the harmonic approximation should be valid. However, we can not rule out a divergence because the system sizes used in our simulations are modest (number of particles $\leq 20,000$). A recent study [@lerner2016] has shown that the low-frequency part of the vibrational spectrum for such values of $N$ is dominated by the *boson peak* modes and the effects of long-wavelength phonon modes are observed only in systems with much larger values of $N$. Since the divergence of $\kappa$ is expected to arise from these phonon modes, simulations of much larger systems would be required to provide a clear answer to the question of whether $\kappa$ diverges as $T\to 0$. Our work shows that the contribution of the boson-peak modes to the thermal conductivity remains finite as $T \to 0$.

We consider the well-known model glass former - the Kob-Andersen binary Lennard-Jones mixture [@Kob:94] (details in section I of *Supplementary Information* (SI)). We consider $N$ particles in a box of dimensions $L_x \times L_y \times L_z$. Our study is done for a number density of $\rho=N/(L_x L_y L_z)=1.2$, for which the Vogel-Fulcher-Tamman ($VFT$) transition temperature of this glass former is $T_0 \approx 0.3$ in reduced Lennard-Jones units. We compute the thermal conductivity at different temperatures above and below the glass transition. The supercooled liquid and glassy states we have studied were obtained via a well-defined cooling protocol [@Sastry:98]. The system is well-equilibrated at a high temperature $(T=2.50)$ in its liquid state and then cooled to a low temperature through a number of intermediate temperature steps. The number of intermediate steps and the amount of time spent in each step determine the cooling rate [@Sastry:98].

[*Thermal conductivity*]{} – Denoting the position and the velocity of the $l$-th particle by ${\vec r}_l=\left\{r^\alpha_l\right\}$ and ${\vec v}_l= \left\{v^\alpha_l\right\}$ respectively (where $\alpha=x,y,z$), the energy current density at point ${\vec r}$ is given by [@Hansen:06]: $$\mathcal{J}^\alpha({\vec r},t)=  \sum_l \delta({\vec r}-{\vec r}_l)[\epsilon_l v_l^\alpha + \frac{1}{2} \sum_{n \neq l}  (r_l^\alpha-r_n^\alpha)j_{l,n}]
 \label{curr_defn}$$ where $\epsilon_l= {\mathbf{v}_l^2}/2+ (1/2) \sum_{n \neq l} V(r_{ln})$ is the energy of the $l$-th particle, and $ j_{l,n}=\frac{1}{2} \sum_\nu  (v_l^\nu +v_n^\nu )f_{ln}^\nu $, with $f_{ln}^\alpha=-\partial{V(r_{ln})}/\partial{r_l^\alpha}$. We evaluated the thermal conductivity by several methods, which we now describe.

[*Nonequilibrium method (NEMD)*]{} – We consider a system with mean temperature $T_m$, impose a small temperature difference $\Delta T$ in the $x$-direction across length $L_x^\prime < L_x$, and measure the average steady-state heat current density $\langle \mathcal{J}^x \rangle = \frac {1} {V} \int_V d{\vec r} \langle \mathcal{J}^x({\vec r},t)\rangle$ where $V$ is the volume of the region in the sample where the measurement is made. The thermal conductivity is then given by $$\kappa=\frac{\langle \mathcal{J}^x \rangle \times L^\prime_x}{\Delta T}.
~\label{kappa}$$

We consider a rectangular geometry, as illustrated in the schematic diagram of Fig. \[figure\_1\]. Periodic boundary conditions were maintained in all directions. We first prepare the initial equilibrium states (at mean temperature $T_m$) via the cooling protocol discussed above. A temperature gradient was then applied by keeping a heat source at temperature $1.05 T_m$ in a region of width $L_x/10$ in the middle of the system, and two heat sinks of width $L_x/20$ at the two ends at $0.95 T_m$. The thermostating of the hot and cold reservoirs was done by drawing the velocities of the particles in each reservoir from a Maxwell-Boltzmann distribution at the appropriate temperatures, at intervals of time 0.1. After an initial transient period ($\delta{t} \sim 10^4$) following the imposition of the thermal gradient, the system reaches a non-equilibrium steady state, wherein the spatial profiles of local temperature and heat current density typically look like those shown in Fig. \[figure\_1\]. The spatial variation of the local temperature $T_i$ and the heat current density $\langle \widetilde{\mathcal{J}}^x_i\rangle$ was obtained by binning $L_x$ into $40$ segments, labelled $i=1,\ldots40$, and doing the averages separately for each segment with $\delta{t} \sim 5\times{10^4}$, after the transient time (details in section II(a) of SI). Using the steady state current value from simulations Eq. (\[kappa\]) with $L^\prime_x=0.4\times L_x$ gives $\kappa$ at temperature $T_m$. We have done averages over $32$ independent MD trajectories.

[*Green-Kubo method(EMD)*]{} – Alternatively, $\kappa$ can be calculated using the Green-Kubo relation [@Hansen:06]: $$\kappa = \frac{1}{3k_BT^2}  \lim_{\tau \to\infty} \lim_{V \to\infty} \frac{\rho}{N} \int_{0}^{\tau} dt \mspace{1mu} \langle {\vec{\mathcal{J}}}_{tot}(0) \cdotp {\vec{\mathcal{J}}}_{tot}(t)\rangle
\label{gkformula}$$ where ${\vec{\mathcal{J}}}_{tot}(t)$ is the integral of the heat current density ${\vec{\mathcal{J}}}({\vec r},t)$ over the whole system and the time correlation function is evaluated at equilibrium.

For the Green-Kubo calculation we considered a cubic simulation box, with the same density of particles as in the nonequilibrium case. An initial equilibrium state is prepared following the cooling protocol described earlier, and subsequently the NVE dynamics is switched on. The fluctuations of the heat current are then measured over a time-window of ${\delta}t~\sim10^4$ as the system evolves and the thermal conductivity ($\kappa$) is calculated using the Green-Kubo formula (Eq. \[gkformula\]). The estimates of $\kappa$ were obtained via averages over $96$ independent trajectories.

In Fig. \[figure\_2\] we compare the values of $\kappa$ measured via the two schemes outlined above, for a given cooling rate. As expected for a disordered system, the magnitude of the thermal conductivity continuously decreases over the entire temperature range, before nearly saturating at very low temperatures. We observe very good agreement between the two different measurements of $\kappa$ over a very broad range of temperatures. Surprisingly, this is true even in the glassy regime, where the two methods provide the same result for states which have the same preparation history, i.e. produced via the same cooling rate. In the rest of the work we have used these two methods independently, in accordance with the question to be addressed. By performing simulations at various system sizes (keeping $\rho$ constant), we have verified that the results for $\kappa$ become essentially independent of system size for $N\sim 10^3$ (EMD) and $N\sim 10^4$ (NEMD). In the inset of Fig. \[figure\_2\] we show the system size dependence of $\kappa$ (details in section II of SI).

[*Effect of cooling rate*]{} – It is known that the cooling rate influences the glassy state obtained at low temperatures [@glassbook]. For example, the mean energy of the underlying ISs, $\overline{E}_{IS}$, corresponding to any temperature, depends on the choice of the cooling rate [@Sastry:98], with slower cooling leading to exploration of lower energy ISs. Using data from our simulations, this is illustrated in the inset of Fig. \[figure\_3\], where we see that below a certain temperature, the variation of $\overline{E}_{IS}$ with $T$ branches out for two contrasting cooling rates. In the same spirit, we check how $\kappa$ (from non-equilibrium measurements) varies with temperatures along the same two cooling branches. This is shown in Fig. \[figure\_3\], and we observe that the slower cooling corresponds to lower values of $\kappa$. However, compared to data shown for $\overline{E}_{IS}$, in this case, the branching occurs at a lower temperature, typically where the dynamics is known to fall out of equilibrium [@glassbook].

[*Effect of aging*]{} – The dependence of thermal conductivity on the history of preparation of the glassy state, as demonstrated above, implies that $\kappa$ would also vary with the age of the glass when the system evolves after a thermal quench from high temperature to low temperatures. To investigate this, we quench the system from $T=2.50$ to $T=0.30$ (which is close to the $VFT$ transition temperature) and let the system evolve in a constant temperature environment for a time $t_w$. Once the system has reached the age $t_w$, the $NVE$ dynamics is switched on. Under such conditions, we measure the total heat current and calculate the corresponding auto-correlation function $\langle{\vec{\mathcal{J}}}_{tot}(t_w) \cdotp \vec{{\mathcal{J}}}_{tot}(t_w+t)\rangle$. In Fig. \[figure\_4\], we show the current auto-correlation function for increasing age $t_w$. Note that the correlators relax quickly in time, even though the structural relaxations are extremely slow at this temperature [@Scheidler:01]. The variation of conductivity $\kappa$ with changing age $t_w$, calculated from these correlation functions using the Green-Kubo formula, is shown in the inset of Fig. \[figure\_4\]: with increasing age, the thermal conductivity decreases. Now, it is known that glassy systems explore deeper minima in the potential energy landscape with increasing age [@Sciortino:99]. Therefore, the observed dependence of $\kappa$ on $t_w$ and our earlier observation regarding the dependence of $\kappa$ on cooling rate suggest that the thermal conductivity of the glass is closely related to the energy of the relevant ISs.

[*Dependence on $E_{IS}$*]{} – We now explore this possible link between properties of ISs and the values of $\kappa$. We consider a number of ISs with mean energy $\overline{E}_{IS}$ and standard deviation $\sim10^{-6}$ and prepare low temperature ($T=0.002$) initial states consistent with small harmonic fluctuations around the potential minimum (details in section IV of SI). In the harmonic theory, the total energy of an equilibrium state with temperature $T$ is $\overline{E}_{IS}+[(6N-3) k_B T/2]$. An initial state with this energy was prepared by choosing positions corresponding to the IS and giving each particle a random velocity taken from a Maxwell distribution at temperature $2T$. MD simulations within the *NVE* ensemble are carried out for $N=1000$. For the states that remain confined to the basin of the initial IS during the course of the simulation, the thermal conductivity is calculated using the Green-Kubo method. In Fig. \[figure\_5\] we show the dependence of $\kappa$ on the energy of the IS – we find $\kappa$ increases linearly with $\overline{E}_{IS}$. This explains why the thermal conductivity decreases with slower cooling, or with increasing age of the system after the thermal quench – the system starts exploring ISs with lower energy.

[*Properties of harmonic excitations*]{} – At very low temperatures, the system mostly remains close to an IS of the potential energy landscape and one can approximate its potential energy to that of a harmonic solid. It is of interest to relate the thermal conductivity to the properties of the harmonic excitations, especially the effect of Anderson localization [@nagel84; @laird91; @kundu:10]. An expansion of the potential energy to quadratic order in the displacements from the IS gives the Hessian matrix which completely describes the properties of the harmonic solid. We ask how the properties of the eigenvalues and eigenfunctions of the Hessian matrix affect thermal transport and the relation between $\kappa$ and $\overline{E}_{IS}$. Following the formulation in [@Allen:93], the conductivity is given by $\kappa= (k_B/V) \int_0^\infty d \omega g(\omega) d(\omega)$, where the density of states $g(\omega)$ and the [*thermal diffusivity*]{} $d(\omega)$ are known completely in terms of the eigenvalues and eigenfunctions of the Hessian matrix (details in section III of SI). We expect the diffusivity of modes to depend on their degree of delocalization which can be quantified by the participation ratio ($PR(\omega)$).

![(color online). (a) Heat diffusivity $d(\omega)$ for three different groups of ISs with different $\overline{E}_{IS}$ and (b) Reduced density of states $g(\omega)/\omega^2$ showing the presence of more extra modes near the boson peak with increase in $\overline{E}_{IS}$. (c) Participation ratio for these three groups of ISs showing the presence of more localized low and high frequency modes with decrease in $\overline{E}_{IS}$.[]{data-label="figure_6"}](figures/figure_6.pdf){width="7.1cm"}

In Fig. \[figure\_6\](a), we consider ISs with three different $\overline{E}_{IS}$ and compare the results for $d(\omega), g(\omega)$ and $PR(\omega)$ for the three cases. We see that, $d(\omega)$ of the ISs with lower $\overline{E}_{IS}$ are smaller over most of the allowed frequency range except for a small region near the boson peak, as compared to the ISs with higher $\overline{E}_{IS}$. We recall that for amorphous solids, excess density of states compared to the Debye law, $g(\omega) \sim \omega^2$, appears in the low frequency region, and this is known as the boson peak [@glassbook]. Here we find that the boson peak is more pronounced for ISs with higher $\overline{E}_{IS}$ than the ISs with lower $\overline{E}_{IS}$, as shown in Fig. \[figure\_6\](b). Finally from the PR (shown in Fig. \[figure\_6\](c)) we see that both the low and high frequency vibrational modes are more extended for the ISs with higher $\overline{E}_{IS}$. This indicates that the higher thermal conductivity is related to the increased delocalization of these vibrational modes, with the high frequency modes playing a more important role (details in section III(e) of SI).

[*Conclusions*]{} — Using numerical simulations, we have studied thermal transport in a model glass-forming liquid. The values of the thermal conductivity, obtained from non-equilibrium and Green-Kubo calculations are found to agree well over a wide range of temperatures. One of our main findings is that the phenomenon of *aging* has a significant effect on thermal transport. Near the glass transition temperature, the conductivity drops by about $50\%$ with increasing age. Similarly the conductivity of the low temperature glass can vary by about $10\%$ depending on the coooling protocol used to form it. The lowering of conductivity with growing age or slower cooling can be rationalized in terms of the system exploring lower energy minima and our numerical results demonstrating that the thermal conductivity increases linearly with the energy of the IS. Further analysis of the harmonic solid associated with the ISs helped us to understand the underlying reasons in terms of the diffusivity and the extent of localization of the normal modes. For the disordered solid, we do not find a diverging diffusivity at low frequencies, but we can not rule out the possibility of a divergence in much larger systems for which long-wavelength phonon modes are expected to dominate the low-frequency part of the vibrational spectrum.

We thank J.-L. Barrat and J. Horbach for discussions; D. Banerjee and H. Khare for their help with figures. PJB & RM acknowledges financial support from CSIR, India. We thank SERC IISc, IMSc and ICTS for computing support. AD thanks support from the Indo-Israel joint research project No. 6-8/2014(IC) and from the French Ministry of Education through the grant ANR (EDNHS). CD acknowledges support from DST, India.

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Chennai: Preparing to cede away thousands of acres of temple lands encroached by squatters across the state, and despite Madras high court’s warning that the state is trying to help encroachers, the Tamil Nadu government has reiterated its stand to issue patta to the illegal occupiers.

“It is not a blanket order and the encroachments in the temple lands will be taken up temple-wise, based on the availability of temple land and after getting concurrence of the Hindu religious and charitable endowments department,” the state said through a counter filed by S Anandhan, deputy secretary, revenue department.

Even without defining the eligibility criteria to benefit under the scheme, the counter-affidavit said government had decided to grant patta for eligible poor families residing in temple lands for a ‘considerable period of time’ and the land which are no longer required for the temple, but only after compensating the department.

The yardstick applicable to residential encroachments in objectionable and non-objectionable public lands is not adopted for temple lands. In respect of such encroachments of temple lands necessary action will be taken to purchase the land from the department for which proposals would be sent to the government from temple-wise through HR and CE commissioner, the affidavit added.

This apart, to safeguard the interest of the temples and to derive income from such lands, it was decided to pay compensation as per the prevailing rules in force, it said.

“It is submitted that the statutory powers of the HR and CE commissioner is not whittled down in any manner and the commissioner will decide each case on its own merits, having regard to the parameters in the Hindu Religious and Charitable Endowments Act,” the state said.

Citing a government order dated November 2, 2018 the state said that now temple lands are permitted to be sold for public purposes to government departments and public-sector undertakings. Accordingly, temple lands encroached by poor for residential purpose would be considered for purchase by the revenue department for grant of house-patta for eligible poor families.


Q:

Sqoop command-How to give schema name for Import All Tables

I am importing all tables from rdbms to hive using the sqoop command(v1.4.6).
Below is the command
sqoop-import-all-tables --verbose --connect jdbcconnection --username user  --password pass  --hive-import  -m 1

This command works fine and it is loading all the tables in default schema.Is there a way to load the tables in particular schema?
Regards
Prakash

A:

Use --hive-database <db name> in your import query.
Modified command:
sqoop-import-all-tables --verbose --connect jdbcconnection --username user  --password pass --hive-import --hive-database new_db -m 1


Abstract:

Alzheimer’s disease is a neurodegenerative disorder and the most common form
of dementia. One of the pathological hallmarks of the disease is amyloid deposition in the
brain. The major cause of amyloid deposition in sporadic Alzheimer’s disease is thought to
be decreased brain clearance of amyloid. There is compelling preclinical evidence that the
blood-brain barrier, a structure that maintains homeostasis in the central nervous system and
protects the brain from harmful substances, plays an important role in amyloid clearance.
Indeed, several dedicated transporter systems are present at the blood-brain barrier which
may have a role in brain amyloid clearance, such as P-glycoprotein (P-gp). In vitro experiments
and animal studies indicated increased amyloid deposition when P-gp was eliminated
by pharmacological blockade or by genetic modification. And as decreased P-gp expression
has been found in AD brains, P-gp became more and more a suspect. Using an imaging
technique called positron emission tomography, P-gp transporter function was found to be
decreased in Alzheimer’s disease patients compared to healthy controls, further establishing the important role of
P-gp in the pathogenesis of the disease. In this review, we summarize what is now known about P-gp in Alzheimer’s
disease pathology, as these transporters may provide a novel target for therapeutic strategies.

Abstract:Alzheimer’s disease is a neurodegenerative disorder and the most common form
of dementia. One of the pathological hallmarks of the disease is amyloid deposition in the
brain. The major cause of amyloid deposition in sporadic Alzheimer’s disease is thought to
be decreased brain clearance of amyloid. There is compelling preclinical evidence that the
blood-brain barrier, a structure that maintains homeostasis in the central nervous system and
protects the brain from harmful substances, plays an important role in amyloid clearance.
Indeed, several dedicated transporter systems are present at the blood-brain barrier which
may have a role in brain amyloid clearance, such as P-glycoprotein (P-gp). In vitro experiments
and animal studies indicated increased amyloid deposition when P-gp was eliminated
by pharmacological blockade or by genetic modification. And as decreased P-gp expression
has been found in AD brains, P-gp became more and more a suspect. Using an imaging
technique called positron emission tomography, P-gp transporter function was found to be
decreased in Alzheimer’s disease patients compared to healthy controls, further establishing the important role of
P-gp in the pathogenesis of the disease. In this review, we summarize what is now known about P-gp in Alzheimer’s
disease pathology, as these transporters may provide a novel target for therapeutic strategies.


Testosterone Replacement Therapy and the Cardiovascular System.
As testosterone replacement therapy (TRT) has emerged as a commonly prescribed therapy for symptomatic low testosterone, conflicting data have been reported in terms of both its efficacy and potential adverse outcomes. One of the most controversial associations has been that of TRT and cardiovascular morbidity and mortality. This review briefly provides background on the history of TRT, the indications for TRT, and the data behind TRT for symptomatic low testosterone. It then specifically delves into the rather limited data for cardiovascular outcomes of those with low endogenous testosterone and those who receive TRT. The available body of literature strongly suggests that more work, by way of clinical trials, needs to be done to better understand the impact of testosterone and TRT on the cardiovascular system.


Former Rangers prodigy Gilmour tipped to thrive on Premier League stage

Gilmour is currently on the fringes of the first-team squad under Frank Lampard. The new manager is giving plenty of opportunities to young players right now, with a transfer ban forcing the club to look to within to freshen the first team.

Two young talents repaid their manager’s faith on Saturday, as Mason Mount and Tammy Abraham scored in an away win at Norwich.

Mount and Abraham celebrate after the former netting at Carrow Road. (Photo by Catherine Ivill/Getty Images)

Gemmill, who has selected Gilmour for Scotland U21s duty in September despite the player still being eligible for U19s, thinks the teenager would fare similarly well if given an opportunity.

Former Rangers prodigy Gilmour tipped for Premier League impact

“Absolutely, 100%,” he asserted, as quoted by the Daily Record. “With my involvement with Billy, there is no question over his emotional intelligence and his attitude.”

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“He’s ready but he has to continue to push and push as that’s really all he can do right now. We know how ambitious Billy is, we know how focused he is, we know how talented he is.

“It’s great Chelsea are giving him that opportunity and we will continue to give him the chance at this level.”

Gilmour in action for Scotland U21s against England in 2018. (Photo by ANNE-CHRISTINE POUJOULAT/AFP/Getty Images)

Verdict

Players everywhere regard the Premier League as the top league in the world and commercially, it certainly tops the lot.

With that in mind, it’s remarkable that Gilmour is so close to playing time for an English heavyweight.

Comments

Jordan joins Rangers News from a Media and Journalism postgraduate degree at the University of Glasgow. Brought up in Belfast as a Rangers fan, he has a passion for writing and has followed British and European football avidly all his life.


Advances in software techniques and processing power over the last decades have finally enabled speech recognition to be effectively used as a viable man-machine interface. This paper describes preliminary work on exploring effectiveness of voice commands and mouse interaction to solve the Hanoi problem. Our first results indicate that performance of speech and other kinds of human-computer interaction (mouse and button) are compatible and that speech-enabled virtual reality applications could be used to train impaired people to perform complex tasks today performed only by people with hand abilities.


Hemimellitene (1,2,3-trimethylbenzene) in the liver, lung, kidney, and blood, and dimethylbenzoic acid isomers in the liver, lung, kidney and urine of rats after single and repeated inhalation exposure to hemimellitene.
The aim of the study has been to explore hemimellitene distribution in blood, liver, lung and kidney as well as toxicokinetics of its elimination from blood of rats after single and repeated inhalation exposure to this compound. Tissue distribution and excretion with urine of 2-dimethylbenzoic acids (2,3-DMBA and 2,6-DMBA) were also evaluated. Male outbred IMP:WIST rats were used in the experiment. The animals were exposed to hemimellitene vapors at the nominal concentration of 25 ppm, 100 ppm, and 250 ppm in the dynamic inhalation chambers for 6 h for single exposure purpose and for 4 weeks (6 h/day for 5 day/week) for repeated exposure purposes. Significantly lower concentrations of hemimellitene were detected in the blood and tissues of animals after repeated inhalation exposure of animals to hemimellitene vapors, which points to reduced retention of the chemical in the lungs of the experimental rats. The trend of hemimellitene elimination from the blood depended solely on exposure intensity, irrespective of exposure time, both after single and repeated exposure. As regards the 2 determined hemimellitene metabolites, the major trend of the metabolic transformation involved formation of 2,3-DMBA. The significantly higher urinary 2,3-DMBA concentration after repeated exposure shows that hemimellitene induces enzymatic processes in the rat.


Immunological and histopathological studies in a rodent model infected with Leishmania infantum promastigotes or amastigotes.
Infection with Leishmania infantum promastigotes (group I) and amastigotes (group II) was evaluated over 32 weeks, using Syrian golden hamsters as an experimental model. Spleen cells strongly responded to the specific antigen at 12 (group I) and 16 weeks (group II) post-inoculation (p.i.) and lower stimulation index values coincided with the parasite burden peak. Western-blot analysis detected antibodies during the 1st week p.i. and the number of recognized proteins increased with the time of infection, reaching a maximum at the peak parasite burden. Histopathology revealed hypoplasia in spleen white pulp and the liver showed a periportal infiltration of inflammatory cells and small granulomas, becoming increasingly more severe as the infection developed. Both organs exhibited a secondary amyloid deposition at the end of the experiment, especially the spleen. In this study, progressive visceral disease was observed as in natural human and canine infections; however, the incubation period was longer in the promastigote than in the amastigote infection.


Raising Money and Giving It Away

Lothian Ruritan Club celebrates 60 years helping the community

By Ashley Brotherton

Beneficiaries of the Lothian Ruritan Club’s scholarships.

Andrew Dennis of Shady Side knew he wanted to go to college. He didn’t know how he was going to manage the costs. As a senior at Southern High School thriving in his welding class, Andrew went on the hunt for scholarships. He found his way to college with the Lothian Ruritan Club, which awards $8,000 in scholarships evenly to eight graduating seniors every year.
Andrew earned the John Hiser Scholarship, which helps seniors wanting to go into culinary or vocational school. When the Ruritans realized that even with the scholarship Dennis, now 18, couldn’t afford the $17,000 tuition for Ohio Technical College, the club helped him find a way.
“That’s what we do,” said Ray Glenn, the Ruritan that worked with Dennis. “We help in the community where it’s needed.”
Help in the community where it’s needed is what the Lothian Ruritans have done for 60 years. This month starts burger burn season, with Ruritans cooking 20 pounds of hamburgers and almost that in hotdogs at Greenstreet Gardens in Lothian. On a good weekend, the smell of the charcoal brings in $2,000 to $3,000 — more money than any other project.
The December citrus sale adds another $3,000.
For the annual spring spaghetti dinner, Frank Gouin, The Bay Gardener, cooks 60 pounds of pasta and tops it with 18 gallons of homemade sauce. Spaghetti supper money bought $4,000 worth of processed food for the South County Assistance Network Food Bank.
“We raise money so we can give it away,” explains Gouin, Lothian Ruritan president.
Dennis has completed his welding training and is working on his certification — again with Glenn’s help, this time in getting his driver’s license.
“Around here,” Glenn says, “you have to have a license to work. It’s the first step.”

The Lothian Ruritan club is extremely generous to the community. As the President of SCAN Food Bank, they provided to us much needed food during the spring and summer months, when donations tend to dwindle.
They are an asset to the community and the people of South County.
Cindy Morgan
President, SCAN Food Bank


Are girls more susceptible to the effects of prenatal exposure to tobacco smoke on asthma?
Prenatal exposure to tobacco smoke through mother's smoking increases the risk of developing asthma later in life. A recent study suggested that this effect is present only in girls. We explored potential differences in susceptibility between boys and girls. We followed all 58,841 Finnish singleton babies born in 1987 through 5 nationwide registries for 7 years and identified all cases of doctor-diagnosed asthma (ICD-9 code 493). The birth registry provided categorical information on the mother's smoking during pregnancy: no smoking (reference), low exposure (<10 cigarettes per day), and high exposure (>10 cigarettes per day). In girls the cumulative incidence of asthma was 0.0245 in the reference group, 0.0310 in the low maternal smoking group (risk difference = 0.0065; 95% CI = 0.0053-0.0076), and 0.0360 in the high maternal smoking group (0.0115; 0.0096-0.0133). The corresponding cumulative incidences for boys were 0.0405, 0.0501 (0.0096; 0.0089-0.0103), and 0.0522 (0.0117; 0.0091-0.0142). In logistic regression analysis adjusting for confounding, the combined effect of male sex and high maternal smoking (compared with female sex and no smoking) was 112% excess risk. This corresponded closely to what would be expected from the additive independent effects of male sex (67% excess risk) and high maternal smoking (44% excess risk). Effects of maternal smoking during pregnancy on the risk of developing asthma are similar in boys and girls, with no interaction on an additive scale.


Q:

free abelian group

let $X=\{a_i\mid i\in I\}$ be a set , then the free abelian group on X is (isomorphic to) the group defined by the generators X and the relations (in multiplicative notation) $\{a_ia_ja_i^{-1}a_j^{-1}=e\mid i,j\in I\}$
here is where i need help..
let the free group on X be F , let N be the normal subgroup of F that is generated by the relations set Y , so i need to prove $G=F/N$ is abelian group and it has a nonempty basis .
to prove the first one is easy , i am stuck on how to prove $F/N$ has a nonempty basis because i don't know what the element in group N general is

A:

From my point of view this is trivial but I could be missing something important from the OP's view.
First, $\;F/N\;$ abelian as clearly $\;F'\le N\;$ by definition of $\;N\;$ . About the non-empty set of generators the reason why I think this is trivial is that if $\;F=\langle\;f_i\;:\;i\in J\;\rangle\;$, then
$$\langle\;f_iN\;:\;i\in J\;\rangle=F/N$$
The only way the above can be empty is if $\;J=\emptyset\iff F=\{1\}\;$ , but for this trivial case...
Also, even if $\;F\;$ is abelian the above cannot be empty, but also this case can be considered trivial and we can, probably, assume $\;|J|\ge 2\;$


Temperate bioerosion: ichnodiversity and biodiversity from intertidal to bathyal depths (Azores).
In the temperate Azores carbonate factory, a substantial fraction of the calcareous skeletal components is recycled by a remarkable biodiversity of biota producing bioerosion traces (incipient trace fossils). To study this biodiversity, experimental carbonate substrates were exposed to colonisation by epilithic and endolithic organisms along a bathymetrical gradient from 0 to 500 m depth, during 1 and 2 years of exposure. The overall bioerosion ichnodiversity is very high and comprises 56 ichnotaxa and ichnoforms attributed to cyanobacteria, chlorophytes, fungi, other micro-chemotrophs, macroborers, grazers and epilithic attachment scars. In the intertidal, hydrodynamic force, partial emersion and strong temperature fluctuations lead to the lowest ichnospecies richness. This contrasts with the highest ichnodiversity found at 15 m under the most favourable environmental conditions. Towards aphotic depths, a gradual depletion in ichnodiversity is observed, most probably because of the restricted light availability and a slowdown in ichnocoenosis development. Analysis of similarity (ANOSIM), in combination with non-metrical multidimensional scaling (NMDS), was used to highlight variability in the relative abundance of traces among depths, substrate orientations and exposure times. Ichnodiversity and abundance of traces decrease significantly with depth and are higher on up-facing versus down-facing substrates, whereas differences between years were not as pronounced. This study demonstrates that statistical methods of biodiversity analysis are not per se restricted to biotaxa but may well be applied also to ichnotaxa. In the analysis of trace fossil assemblages, this approach supports the recognition of diversity patterns and their relation to environmental gradients.


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