**5. Conclusions**

In conclusion, our findings suggest that the pilot programme stimulated some improvement in adolescents' subjective well-being and trait emotional intelligence, but did not impact social anxiety. Therefore, on the basis of quality physical education and the social and emotional learning approach,

### *Int. J. Environ. Res. Public Health* **2019**, *16*, 1821

the implementation of such programmes is recommended given the possible psychological benefits for adolescents in the educational context. A commitment to sports and other physical-sport activity options within a quality physical education framework, efficiently applied by means of relevant pedagogical models (such as sport education), may play an important role in students' integral development [77,78].

**Author Contributions:** P.L., J.G. and J.C. conceived and designed the experiments; P.L., J.G. and J.C. performed the experiments; P.L., J.G. and J.C. analysed the data; P.L., J.G. and J.C. contributed reagents/materials/analysis tools; and P.L., J.G. and J.C. wrote the paper.

**Funding:** This research received no external funding.

**Acknowledgments:** We thank Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript. **Conflicts of Interest:** The authors declare no conflicts of interest.


*Editorial* **Advances in Urological Cancer in 2022, from Basic Approaches to Clinical Management**

**Claudia Manini 1,2,\*, Estíbaliz López-Fernández 3,4, José I. López 5 and Javier C. Angulo 6,7**

	- 5 Biocruces-Bizkaia Health Research Institute, 48903 Barakaldo, Spain

This Special Issue includes 12 articles and 3 reviews dealing with several basic and clinical aspects of prostate, renal, and urinary tract cancer published during 2022 in *Cancers*, and intends to serve as a multidisciplinary chance to share the last advances in urological neoplasms.

This international forum of urological cancer includes different perspectives from 14 different countries: Canada, New Zealand, Italy, the USA, Germany, South Korea, Japan, Spain, Austria, China, the Netherlands, Taiwan, Poland, and the UK. An overview of these contributions shows the great variability of topics currently impacting the urological clinical practice, from the molecular mechanisms underlying prostate cancer development, for example, to the appropriateness of the robotic surgery in radical prostatectomy or partial nephrectomy and the current role of prostate-specific membrane antigen positron-emission tomography (PSMA-PET) imaging in prostate cancer. In addition, this "Urological Cancer 2022" Issue is also an opportunity to highlight some relevant international achievements of the specialty published elsewhere during 2022.

Pellerin et al. [1] analyzed the effects of the chronic exposition to bisphenols in bladder epithelium. Bisphenols A and S are chemical compounds used in the plastic industry to produce polycarbonates necessary for generating epoxy and vinyl ester resins. These worldwide distributed composites are industrially produced by the condensation of phenol and acetone and make up part of several plastics such as PVC. These products are insoluble in water and are present in the urine in normal conditions. Importantly, they are endocrine disruptors that interfere with cellular signaling pathways in urothelial cells [2]. Using normal urothelial cells (pediatric volunteers) and non-invasive (RT4, cell line ATCC HTB-2) and invasive (T24, cell line ATCC HTB-4) bladder cancer cells, the authors evaluate the impact of bisphenols on the energy metabolism, proliferation, migration, and pro-tumorigenic effect in human urothelium. They conclude that a chronic exposure to bisphenols A and S increases the proliferation rate and decreases the migration capacities of normal urothelial cells, which could result in urothelial hyperplasia. By contrast, these chemical products increase the energy metabolism, physiological activity, and cell proliferation, which could eventually promote urothelial cancer progression, especially from non-invasive to invasive variants.

The clinical identification of aggressive variants of prostate carcinoma requires more accurate markers. Reader et al. [3] have analyzed how the variations in the expression of Activins B and C impact the growth of PNT1A and PC3 prostate cancer cell lines. Activins are homo- or hetero-dimers belonging to the transforming growth factor-β family involved in prostate homeostasis, which are dysregulated in prostate cancer [4]. The authors have detected that the expression of Activin B was increased in prostate cancer samples, with a

**Citation:** Manini, C.;

López-Fernández, E.; López, J.I.; Angulo, J.C. Advances in Urological Cancer in 2022, from Basic Approaches to Clinical Management. *Cancers* **2023**, *15*, 1422. https:// doi.org/10.3390/cancers15051422

Received: 13 February 2023 Revised: 14 February 2023 Accepted: 17 February 2023 Published: 23 February 2023

**Copyright:** © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

higher Gleason index, and that its overexpression inhibited the growth of PNT1A cells and increased PC3 cells' growth and migration. Interestingly, Activin C showed the opposite expression, with decreased immunostainings in prostate cancer cells with high Gleason grades, an increased overexpression in PNT1A cells, and a decreased growth in PC3 cells. The authors conclude that the combination of Activin B increasing and Activin C decreasing is associated with a higher Gleason grade in prostate adenocarcinoma and suggest its potential usefulness as prognostic biomarkers in this neoplasm.

Tossetta et al. [5] focused on the role of the ciliary neurotrophic factor (CNTF) in prostate cancer. Despite the fact that several crucial pathways such as MAPK/ERK, AKT/PI3K, and Jak/STAT regulate prostate cancer progression are triggered by CNTF, little is known about the effect of this member of the IL-6 family. The authors analyze the immunohistochemical expression of CNTF and its receptor in androgen-responsive (*n* = 10, radical prostatectomy samples) and castration-resistant (*n* = 10, transurethral resection samples) prostate cancers. Additionally, CNTF and its receptor expression are analyzed in androgen-dependent (LNCaP) and androgen-independent (11Rv1) prostate cancer cell lines by Western blotting and immunofluorescence. They also show that CNTF treatment downregulates MAPK/ERK and AKT/PI3K pathways, inhibiting the matrix metalloproteinase-2 (MMP-2), a major component of the extracellular matrix degrader, and what is mainly responsible for tumor invasiveness. The authors conclude that CNTF plays a key role in the remodeling of the prostate cancer environment and suggests that this cytokine may modulate prostate cancer invasion. CNTF could represent a novel therapeutic approach in patients with castration-resistant prostate cancer.

Zapala et al. [6] investigated the usefulness of the preoperative systemic immuneinflammation index (SII) in predicting survival in a retrospective series of 421 patients with non-metastatic prostate cancer treated with radical prostatectomy. They found that a high SII was an independent predictor of overall survival. Furthermore, the combination of high age-adjusted Charlson Comorbidity Index (ACCI), the Cancer of the Prostate Risk Assessment Postsurgical score (CAPRA-S), and the SII identifies patients at the highest risk of death. The authors conclude that SII should be added to the prognosticators of patients with prostate cancer.

Clear cell renal cell carcinoma (CCRCC) is a perfect example of tumor complexity and a permanent target of analysis in recent years. In this collection, Shi et al. [7] analyzed the value of a ferroptotic gene-based signature in the prognosis of several series of CCRCC downloaded from the GEO database. The analyzed genes were obtained from the FerrDb V2 database. They identify a set of nine genes with prognostic implications differentially expressed in CCRCC, and found that the GLS2 enzyme, encoded by the *GLS2* gene and regulated by p53, may be a ferroptotic suppressor in CCRCC. The authors conclude that this nine-gene signature could eventually be an independent prognosticator in this neoplasm and advice for further investigations. Aside from that, several interesting investigations have been performed this year and deserve a short mention. Intratumor heterogeneity (ITH) is a constant, extensively analyzed event in CCRCC and its level has been correlated in 2022 with tumor aggressiveness. A mathematical study based on game theory [8] and a histological analysis [9] confirm that aggressive variants of CCRCC typically display low levels of ITH and agree with a genomic analysis of 101 cases already published in 2018 [10]. Additionally, several investigations have analyzed the influence of tumor growth patterns in the inter-regional genomic variability of these neoplasms [11], supporting the need for a personalized tumor sampling to strengthen tumor analysis [12,13].

In their review, Christenson et al. [14] revisited all the treatment modalities available so far in prostate cancer, focusing especially on the targets to interrupt the biological progression in lethal forms of prostate cancer, that now have a 5-year overall survival of only 30%. They revise current therapies, considering first low-risk and high-risk non-metastatic cancer, and then how to target metastatic cases, including hormone therapy, chemotherapy, PSMA-targeted radiation, genome-targeted precision therapy, and immunotherapy. The authors also review the ETS fusion positive (involving *TMPRSS2*, *SLC45A3*, *ETV1*, *ETV4*, and *FLI1* genes) and negative (involving *SPOP*, *FOXA1*, and *IDH1* genes) molecular subtypes of prostate cancer. The intimate mechanisms regulating metastatic castration-resistant prostate cancer and the androgen receptor ablation for intercepting advanced cancer are also analyzed. The intestinal microbiota as a potential promoter of castration-resistant tumor variants, the innovations in managing neuroendocrine tumors, and the difficulties of applying immune checkpoint inhibition in prostate cancer appear among the future directions in the review. Finally, the authors point also to CRISPR/Cas enzymes-assisted gene editing as a promising arena to develop further in prostate cancer management.

Other clinically oriented topics have also been incorporated in this Special Issue on the advances in urologic cancer regarding patient follow-up, diagnosis, and treatment. A very interesting one is a randomized clinical trial performed in the Netherlands which deals with the transition of care between a specialist and primary care physician [15]. Patients were randomized and allocated to specialist or general practitioner care for a head-to-head comparison. Several advantages of primary care follow-up over specialists' have been identified, including accessibility and more personalized attention, with a similar effectiveness. This study also identifies several challenges that must be addressed before the transition to primary-care follow-up can be a reality, by using quality indicators and improving communication and collaboration. However, another report from the same study shows that from the patient's perspective, hospital-based follow-up is preferred, but efforts should be made to improve physician's knowledge about personal aspects of the patient, improve symptoms management, and promote global health [16].

A series of articles evaluate the diagnostic pitfalls of prostate cancer by using different tools including PSA, multiparametric magnetic resonance imaging (mpMRI), and new generation imaging with the PSMA-PET modality; the latter has many therapeutic implications. In this respect, a study addresses the variables associated with false-positive PSA results using real-world data in a Spanish cohort of 1664 patients followed for two years. The false-positive results were as high as 47%, resulting in a positive predictive value of merely 13% [17]. This rate is much higher than previously reported in trials with screening data [18] Many factors were demonstrated to be associated with the presence of false-positive results, including age, previous PSA evaluation, family history of prostate cancer, and alcohol intake, but these associations were sustained only in asymptomatic patients [17]. These data do not serve to evaluate overdiagnoses and overtreatment but help to sustain that the PSA era in prostate cancer diagnosis should be closing.

A study in this Special Issue addresses the limitations of mpMRI for primary prostate cancer diagnosis in the form of a systematic review and meta-analysis that compare mpMRI with prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging [19]. With the limitation of significant heterogeneity observed, PSMA-PET computerized tomography (CT) seems superior to mpMRI in primary cancer diagnosis, but not in the definition of cancer location within the gland. However, as can be expected from a whole-body procedure, PSMA-PET CT has valuable potential for tumor staging. False-positive MRI is another troublesome reality in clinical practice as it is not easy to differentiate false and real positive lesions, thus making evident the difficulty of further advancing in the MRI diagnostic ability [20]. PSMA-PET CT has also been investigated to solve MRI Prostate Imaging Reporting and Data System (PI-RADS) 4–5 lesions and negative biopsy discordance [21] and also the combination of PSMA-PET CT and mpMRI is being currently investigated in the MP4 clinical trial in which PI-RADS 4 or 5 lesions ≥10 mm on mpMRI are given the option of a PSMA-PET CT before biopsy. The intention of this approach is to predict better aggressive prostate cancer. That opens a new perspective to evaluate the feasibility of proceeding to prostate cancer surgery directly without a biopsy [22]. Additionally, PROSPET-BX clinical trial, currently undertaken in Italy, might confirm the superiority of PSAM-PET CT/transrectal ultrasound (TRUS) fusion prostate biopsy over mpMRI/TRUS fusion biopsy to further spare unnecessary biopsies [23].

Inspired by all these changes of paradigm, an excellent review on the clinical applications of PSMA-PET CT examination in patients with prostate cancer has been included

in this Special Issue [24]. The article addresses the limitations and pitfalls of this new generation diagnostic imaging modality and emphasizes its therapeutic implications also. In fact, prolonged progression free and overall survival has been very recently confirmed in castration-resistant prostate cancer with lutetium Lu 177 vipivotide tetraxetan (177Lu-PSMA-617) radioligand therapy [25]. Additionally, the PSMA-PET CT-guided intensification of radiotherapy is being investigated in a Canadian clinical trial, with special effort on cancer control, long-term toxicity, and health-related quality of life issues [26].

Carbon-ion radiotherapy, another modality to improve the effectiveness of radiation therapy, has been also evaluated in this Special Issue, with a retrospective study focusing on the older population of patients with prostate cancer [27]. This study confirms that carbon-ion radiotherapy is a safe and effective high-dose intensive treatment. This modality of radiation has been popular in different institutions in Japan for the treatment of different urologic cancers [28]. This modern technology provides several unique physical and radiobiologic properties that allow low levels of energy to be deposited in tissues proximal to the target, while the majority of energy is released in the target itself. That may have important advantages, especially in the setting of recurrent disease [29]. Another modality of radiation is extreme hypofractionation with stereotactic body radiation therapy (SBRT) in which treatment is delivered in one to five fractions, an encouraging alternative in the low- and intermediate-risk profile of patients that competes with high-dose brachytherapy [30,31].

Surgery has also seriously evolved to consider robotic prostatectomy the gold standard of surgical care for localized prostate cancer, that improves the functional outcomes of urinary continence and potency. This is also the topic of another article in the Special Issue [32]. Still, the definition of continence "without pads" or "social continence" makes difficult the comparison of the results [33]. New and effective modalities to surgically correct post-prostatectomy incontinence have been developed in recent decades and can be used both for stress urinary incontinence after prostatectomy and after radiation therapy [34–36].

Another interesting application of robotics in surgical urologic oncology is partial nephrectomy. The clinical benefits of indocyanine green florescence in robot-assisted partial nephrectomy are discussed in another element of this Special Issue. Reduced blood loss without a negative impact in the positive surgical margin rate is suggested using green dye [37]. However, future prospective randomized controlled trials are needed to confirm the presumed operative and functional advantages of this approach. Moreover, the issue presents another very interesting collaboration regarding metastatic renal cell carcinoma treatment, a field that has been subject to important paradigm changes in recent years [38]. The German multicenter prospective study PAZOREAL presented by Doehn et al. [39] reveals very interesting data on the effectiveness and safety of pazopanib (firstline), nivolumab (second-line), and everolimus (second- and third-line) in a real-life setting. This sequence is widely used in clinical practice. Targeted treatments for metastatic renal cell carcinoma allow for a more tailored approach, but predictive elements for immunecheckpoint inhibitors or tyrosine kinase inhibitors as a first-line treatment still lack genuine prediction markers [40].

Many studies have faced the optimal management of bladder urothelial malignancy in recent years. Some have searched for new therapeutic alternatives in the scenario of Bacillus Calmette-Guerin (BCG) shortage to prevent urothelial cancer recurrence and progression. Device-assisted intravesical chemotherapy using recirculating hyperthermic mitomycin-C (HIVEC) has been widely used in Spain [41]. Current new evidence favors the use of HIVEC in high-risk non-muscle-invasive bladder cancer [42], but not in the intermediate risk [43]. Many other studies have extended to step beyond classical morphologic parameters and stratify the prognosis of muscle-invasive bladder cancer according to new molecular markers that take into account basal or luminal phenotypes discovered [44,45]. A further step that is currently being undertaken is the evaluation of the intratumor microenvironment landscape, with implications not only in prognosis, but also in the response to systemic immunotherapy [46]. In this sense, immune-checkpoint inhibitors have been recently

approved as a second-line treatment for metastatic bladder cancer and are currently being investigated in a neoadjuvant setting in non-metastatic disease [47,48].

Upper urinary tract urothelial carcinoma is another malignancy addressed in the Special Issue. Ha et al. revealed that intravesical recurrence after radical nephroureterectomy is associated with flexible but not with rigid diagnostic ureteroscopy [49]. This specific report opens a new perspective that requires a further evaluation in large-population controlled studies. The issue of intravesical recurrence after upper urinary tract cancer diagnosis and treatment is a big unsolved problem in the comprehensive management of urothelial malignancy. Several meta-analyses have confirmed the higher rate of intravesical recurrence after radical nephroureterectomy in patients who underwent diagnostic ureteroscopy preoperatively [50–52], but with no concurrent impact on long-term survival [52]. Probably the negative impact on intravesical recurrence free survival is due more to endoscopic biopsy than to ureteroscopy itself. As the use of flexible ureteroscopy is routinely recommended by clinical guidelines [53], future studies are needed to assess the role of immediate postoperative intravesical chemotherapy in patients undergoing biopsy during ureteroscopy for suspected upper tract urothelial cancer.

In summary, "Urological Cancer 2022" is a remarkable piece of knowledge that presents new relevant clinical, molecular, imaging, and therapeutic data in the urological field and invites researchers in urologic malignancy to enter a multidisciplinary approach and face some of the most relevant and current topics in urology.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

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*3.2. Characterization of the Drug–CD Binary Systems*

DSC curves of pure HCT and CDs and of their binary systems obtained with the different techniques were recorded in order to investigate the effect of the CD type and preparation technique towards drug amorphization and complexation (Figure 2A). Thermograms of pure drug submitted to the different treatments used for the preparation of the binary systems were also recorded, in order to evidence any effect of the preparation technique on drug solid-state properties.

**Figure 2.** DSC curves of pure HCT (**A**) untreated or submitted to kneading (KN), grinding (GR) or dissolution-solvent evaporation (EV) and its binary systems with βCD (**B**), HPβCD (**C**), HEβCD (**D**), SBEβCD (**E**), and RAMEB (**F**), obtained by physical mixing (i.e., PM), co-grinding (GR), kneading (KN), and co-evaporation (COE).

The drug alone thermogram showed a sharp melting peak (Tpeak = 274.4 ◦C and ΔH = 152.8 J·g−1), as expected for an anhydrous crystalline compound. The kneading does not seem to affect the thermal behavior, causing just a slight decrease in Tpeak (272.2 ◦C) and RDC (98.96%).

The thermal curve of the drug submitted to the grinding process showed an exothermic phenomenon at 134.5 ◦C which is attributed to the recrystallization of the drug fraction amorphized during the grinding procedure; it was followed by the melting peak at 271.2 ◦C, whose reduced intensity (ΔHfus128.1 Jg−1) indicated some loss of crystallinity (RDC 83.23%). In the evaporated product, the drug melting peak at 274.1 ◦C was characterized by a sensible reduction of fusion enthalpy (72.1 Jg−1). The calculated RDC of 46% suggested an appreciable drug amorphization, as a consequence of its dissolution in the water-ethanol mixture and the following solvent evaporation.

In Figure 2B, the thermal profiles of HCT binary systems with βCD are reported. The DSC curve of βCD in the examined temperature range was characterized by an intense and broad endothermic effect that ranged between 50 to 130 ◦C, due to its dehydration. The PM showed the CD dehydration band, followed at higher temperatures by an endothermic event characterized by the presence of two peaks at 265 ◦C and 269 ◦C. These can be attributed to the partial superimposition of the drug melting and the CD thermal decomposition, both shifted at lower temperature than the corresponding pure components, due to their co-presence, as observed also by other authors [27,28]. In fact, CD alone started to decompose usually over 300 ◦C [29]. A thermal behavior substantially similar to that of PM was found for GR, KN, or COE products, suggesting poor host–guest interactions. A rather similar behavior (Figure 2C) was observed for the series of products with SBEβCD. As previously observed by Cirri et al., 2017, the thermal profile of this CD showed a broad endothermic effect between 60 to 110 ◦C due to its dehydration, and another endothermic band between 250 and 280 ◦C, due to degradation phenomena [30]. All binary systems prepared with the different techniques showed the superimposition of HCT melting and CD decomposition phenomena, similar to that observed in the simple PM. As for the thermal profiles of binary systems with HPβCD, HEβCD and RAMEB (Figure 2D–F, respectively) after the initial broad endothermic effect, due to the amorphous CD dehydration, the drug and CD endothermic decomposition phenomena in the range 250–260 ◦C was still barely detectable only for the PM with HPβCD, while the drug melting peak completely disappeared in all other systems, where only the CD decomposition band was observed.

In order to better elucidate the DSC findings and, in particular, to evidence any possible artifact of the technique, due to a heating-induced interaction between the components as a consequence of the thermal energy supplied to the sample during the DSC scans [31], XRPD analysis was conducted. As shown in Figure 3A, the patterns of pure drug and βCD presented several sharp peaks, characteristic of crystalline substances, whereas all βCD derivatives, as shown, as example, for HPβCD, presented an almost flat pattern typical of amorphous substances. Representative drug peaks were clearly detectable in the patterns of all PMs (Figure 3B), even if reduced in intensity, particularly, in combinations with the amorphous partners, indicating that any solid-state interaction occurred during the simple mixing of drug and CDs. However analogous results to those of PMs were also obtained for all binary systems with βCD and different CD derivatives, with the only exception for COE products obtained with RAMEB and SBEβCD (Figure S1, Supplementary Material). Thus, the disappearance of the drug melting peak, observed in the other cases can be attributed to heating-induced interactions due to the thermal energy supplied to the sample during the scan. However, the completely amorphous pattern exhibited by the COE products with RAMEB and SBEβCD proved that the actual drug amorphization and complexation was achieved only by this preparation technique with these CDs (Figure 3C).

**Figure 3.** XRPD patterns of pure HCT and CDs (**A**) and of equimolar physical mixtures (PM) (**B**) with all CDs and the co-ground (GR), kneaded (KN), and co-evaporated (COE) products with RAMEB (**C**).

The results of dissolution rate studies performed on pure drug, both untreated and submitted to the different techniques and on the different binary systems with all the CDs, are presented in Figure 4.

**Figure 4.** Dissolution profiles of pure HCT (**A**) untreated ( red line) or submitted to kneading ( blue line), grinding ( green line), or dissolution-solvent evaporation (x violet line) and from its binary systems with βCD (**B**), SBEβCD(**C**), and RAMEB (**D**), obtained by physical mixing (PM) ( red line), kneading (KN) ( blue line), co-grinding (GR) ( green line), and co-evaporation (COE) (x violet line). Each value represents the mean of 3 experiments.

As shown, HCT alone (Figure 4A) always reached a solubility of 1 mg/mL, even if the treatments, especially the grinding one, initially allowed a more rapid release, probably due to a particle size reduction of the powder. In binary systems with βCD (Figure 4B) a better profile was also observed for the simple PM that reached a plateau level of 1.45 ± 0.5 mg/mL, due to the improved drug wettability and possible in situ complexation phenomena. A little more favorable effect on the drug dissolution rate, particularly in the first minutes, was observed for all treated products, in virtue of the more intimate contact between the components brought about by the sample preparation method. Similar results were obtained for drug systems with HEβCD and HPβCD (data not shown), regardless of the sample preparation technique. Instead, significant differences were observed for the series of products with SBEβCD and RAMEB (Figure 4C,D) especially for COE systems, which achieved plateau levels around 5.5 ± 0.3 and 6.8 ± 0.2 mg/mL, respectively. It should be pointed out that the COE systems with SBEβCD and RAMEB were the only ones actually containing the drug in an amorphous/complexed status, as revealed by XRPD analysis. Moreover, the results were in accordance with phase solubility studies, where SBEβCD and RAMEB showed the higher complexing and solubilizing efficiency towards HCT.

Taking into account these results, co-evaporation was selected as the most effective preparation technique and RAMEB as CD that lead to the best drug dissolution profile.


6. Conclusions

These results are significant. As seen in Table 15, a development incorporating a microgrid uses over 10 times the natural gas in all cases than the identical development drawing power from the local distribution grid. However, Table 16 definitively shows that the use of a microgrid would greatly reduce the greenhouse gas emissions from the development, with approximately half of

On national power grid Trigenerating microgrid

water

Cairo 1.0E+07 4.3E+09 0 4.4E+09 0.0E+00 2.7E+09 0.0 1.5E+10 1.8E+10 1.4E+10 Lagos 1.0E+07 0.0E+00 0 1.0E+07 0.0E+00 0.0E+00 0.0 1.5E+10 1.5E+10 1.5E+10 Shanghai 1.0E+07 7.4E+09 0 7.4E+09 0.0E+00 4.5E+09 0.0 1.5E+10 2.0E+10 1.2E+10 Mumbai 1.0E+07 0.0E+00 0 1.0E+07 0.0E+00 0.0E+00 0.0 1.5E+10 1.5E+10 1.5E+10 London 1.0E+07 1.4E+10 0 1.4E+10 1.0E+07 9.5E+09 0.0 1.3E+10 2.2E+10 8.8E+09

NYC 1.0E+07 1.2E+10 0 1.2E+10 1.0E+07 7.8E+09 0.0 1.5E+10 2.3E+10 1.0E+10

1.0E+07 7.3E+09 0 7.3E+09 0.0E+00 4.6E+09 0.0 1.5E+10 2.0E+10 1.2E+10

1.0E+07 0.0E+00 0 1.0E+07 0.0E+00 0.0E+00 0.0 1.5E+10 1.5E+10 1.5E+10

Heat AC SUM Hot

Micro-Grids - Applications, Operation, Control and Protection

NG consumption: with microgrid compared to without microgrid.

City Hot

Mexico City

Sao Paolo

Table 15.

Table 16.

16

water

Cubic feet NG annually Cubic feet NG annually Difference

Heat AC Turbine SUM

trigeneration from the outset, all upstream emissions from electricity generation are eliminated. Additionally, the use of waste heat in the building systems eliminates emissions from the production of hot water, halves the emissions from building heat, and also eliminates any emissions from air conditioning (bearing in mind that, in a conventional arrangement, air-conditioning emissions would be included in electricity generation emissions). Finally, Table 14 shows that incorporating maximal renewable assets by design accounts for roughly 20% of the electricity production which, at 50% generator efficiency,

Tons/year On power grid Microgrid Reduction (%) City CO2 SO2 CO2 SO2 CO2 SO2 Cairo 9.84E+04 4.80E+02 4.46E+04 2.67E+00 54.64% 99.44% Lagos 7.54E+04 5.25E+02 2.81E+04 1.68E+00 62.80% 99.68% Shanghai 1.12E+05 6.56E+02 5.58E+04 3.34E+00 50.08% 99.49% Mumbai 7.93E+04 6.73E+02 2.81E+04 1.68E+00 64.55% 99.75% London 1.49E+05 4.93E+02 8.58E+04 5.14E+00 42.53% 98.96% Mexico City 1.14E+05 4.70E+02 5.62E+04 3.36E+00 50.88% 99.28% NYC 1.41E+05 8.04E+02 7.56E+04 4.52E+00 46.21% 99.44% Sao Paolo 7.81E+04 5.01E+02 2.82E+04 1.69E+00 63.87% 99.66%

Comparison of greenhouse emissions for development: without vs. with microgrid.

the CO2 and virtually all SO2 emissions eliminated. By incorporating

Urbanization of populations is occurring at an accelerating pace worldwide, and, in all countries, the increasing densification of population is putting a strain on the pre-existing infrastructure. Depending on the state of national economic development, that infrastructure could be robust, aging, or nonexistent, but was not designed to support the increasing strain. Additionally, this seismic population shift requires housing and employment opportunities in relatively small geographic areas. While growth has always bought opportunity, that opportunity was never immediate or evenly distributed. Hence, slum populations are increasing, and both housing and economic opportunity are increasingly scarce.

History has shown that economies cannot be managed, but it is the job of the government to "promote the general welfare" [69]. At present, various local, national, and international entities are promoting the general welfare through establishing programs to create sociological and environmentally sustainable opportunity. These incentives recognize the existence of a need which can be addressed by a new model of urban growth, one that is economically advantageous and sociologically and environmentally sound, such as the design model proposed herein. The work presented develops a new model for urban development, a model which incorporates a myriad of mature technologies into a real estate development at the design stage. The model bases the development around a self-contained microgrid using trigeneration of power where, at the first stage, fossil fuel-powered turbines produce electricity and heat which, at the second stage, powers a steam turbine to produce more electricity. The third stage of trigeneration is to use the remaining exhaust heat to provide building heat, hot water, and air conditioning. The system is supplemented by renewable solar and wind power, with the buildings designed from the outset to maximize such assets. Modern power storage assets are included in the design to balance the load between times of high usage and low usage.

The study demonstrates that the proposed model succeeds in meeting all sustainability requirements. It is more profitable than constructing the same development on the national power grid. This is vital since economic sustainability is a sine qua non for any urban development. It balances load and generation capability on a large scale, allowing the construction of large numbers of buildings to accommodate increasing populations with essentially no impact on the existing power distribution infrastructure. It is also environmentally sustainable, producing fewer emissions than traditional developments on the same scale.

These conclusions point to the viability and the economic and environmental desirability of proceeding with urban development under the model herein presented and also lead to a sociological conclusion. Cities are historically built by the poor striving to make a better life for themselves and their families. In developed countries, the consequence of real estate development is too often to push such people out of their homes and further to the fringes. In developing countries, such people are often not even considered, relegated to living in shanty towns. The economic and environmental advantages of this development model present an opportunity to promote the general welfare of all. Environmental financial incentives, coupled with increased profitability, will allow for the maintenance of exceptional living conditions at comparatively low rents. Since renewability and regeneration are incorporated into the building design,

heat and hot water, so necessary for everyday life, will be readily available. Lower rents are economically possible since all these usual living expenses are being provided for by the same source. Most importantly, the model is scalable and variable and power is fungible. A commercial tower was included in this study to both provide an economic focus point to start the development and to provide jobs to the people living in the residential towers because real-world data was made available. The model could be applied to any combination of residential, commercial, retail, or industrial spaces providing centers for human advancement, with both jobs and housing provided at an economically and environmentally favorable rate.


**Alternative Sweeteners Modify the Urinary Excretion of Flavanones Metabolites Ingested through a New Maqui-Berry Beverage**

#### **Vicente Agulló 1, Raúl Domínguez-Perles 1,\*, Diego A. Moreno 1, Pilar Zafrilla 2 and Cristina García-Viguera 1**

Received: 1 November 2019; Accepted: 26 December 2019; Published: 3 January 2020

**Abstract:** Dietary sugar has been largely related to the onset of metabolic diseases such as type 2 diabetes and obesity, among others. The growing awareness on the close relationship between the dietary habits and this health disturbance has encouraged the development of new beverages using alternative sweeteners that could contribute to combat the above referred pathophysiological disorders. To gain further insight into this issue, the present work, upon an acute dietary intervention, evaluated the urinary excretion of flavanones ingested through polyphenols-rich beverages composed of maqui berry and citrus, with the aim of establishing the highest urinary excretion rate and metabolite profiles. The functional beverages evaluated were supplemented with a range of sweeteners including sucrose (natural and high caloric), stevia (natural and non-caloric), and sucralose (artificial and non-caloric) as an approach that would allow reducing the intake of sugars and provide bioactive phenolics (flavanones). The juices developed were ingested by volunteers (*n* = 20) and the resulting flavanones and their phase II metabolites in urine were analyzed by Ultra-High Performance Liquid Chromatography ElectroSpray Ionization Mass Spectrometry (UHPLC-ESI-MS/MS). A total of 16 metabolites were detected: eriodyctiol, naringenin, and homoeriodyctiol derivatives, where peak concentrations were attained 3.5 h after beverage intake. Sucralose and stevia were the sweeteners that provided the highest urinary excretion for most compounds. Sucrose did not provide a remarkable higher elimination through urine of any compounds in comparison with sucralose or stevia. These results propose two alternative sweeteners to sucrose (sucralose and stevia), an overused, high caloric sweetener that promotes some metabolic diseases.

**Keywords:** dietary intervention; maqui-citrus juice; flavanones; urinary excretion; UHPLC-ESI-QqQ-MS/MS

#### **1. Introduction**

Recently, scientific evidence has shown that sugar intake stimulates brain reward pathways [1–4], the basis for the consumers choosing the types of foods and beverages that use sweeteners such as sucrose, glucose, and saccharine liquid, among others. This consumption pattern has been related with the rising incidence of metabolic disorders, such as type 2 diabetes, by promoting obesity and insulin resistance [5–7]. Associated to these pathophysiological processes, an increase of strokes has also been reported [8]. Thus, in this aspect, sweetened beverages constitute the main dietary source of sugars in the human diet [9].

Global strategies against the impact on health of sugar consumption are focused on establishing balanced diets that avoid the excessive consumption of sweeteners [10]. In connection with this strategy, a number of studies have suggested the consumption of bioactive molecules (phytochemical compounds, such as flavanones) which have a vasodilator activity that contributes with the improvement of endothelial function, and thus, can help prevent the deleterious effects associated with sugar [10]. However, the bioavailability of these bioactive compounds is generally low (up to 10% of the total intake) and could be strongly conditioned by the physico-chemical properties of the matrix (foods and beverages). Therefore, a recent study has proposed the use of alternative sweeteners such as stevia, as a trans-glycosylated food additive that could potentially improve the stability, bioaccessibility, and bioavailability of polyphenols [11]. In addition, the strategy of using other sweeteners is in agreement with the recommendations by the World Health Organization (WHO) to reduce the intake of free sugars to values less than 10% in order to diminish the array of pathophysiological disorders associated with their consumption [12].

To contribute to the enhanced consumption of dietary sources of bioactive phytochemicals, in the last few years diverse fruits have been selected and characterized for the development of new bioactive beverages, which have a high bioavailability and content of bioactive compounds, and contribute with lowering the risk of a range of diseases [13–15]. In the work developed by Gironés-Vilaplana et al. [13], Maqui (*Aristotelia chilensis* (Mol.) Stuntz), a purple blackberry from Chile and Argentina, was chosen due to its importance as a "superfruit" according to its health properties, such as a high antioxidant capacity, cardioprotection activities, and inhibition of adipogenesis, and diabetes symptoms [13].

In addition to red fruits, citrus fruits have been selected as ingredients of the new beverage due to their phenolic composition, as they are flavonoid-rich fruits. Citrus juices have significant effects for decreasing diastolic blood pressure, enhancing endothelium-dependent microvascular reactivity and increasing the pro-coagulant activity [16,17]. On the other hand, this type of beverage contains many bioactive nutrients and non-nutrients, which can provide health benefits beyond nutrition and cardiovascular disease, cancer, diabetes, and obesity [18]. The most abundant polyphenols in citrus are flavanones, with naringenin (N), eriodyctiol (E), and hesperidin (H) being the most representative compounds of this family, with the latter being promoted as a preventive molecule against cardiovascular diseases [16].

This article deals with the influence of diverse sweeteners on the urinary excretion of flavanones on healthy humans after an acute administration of a polyphenols-rich beverage composed of maqui berry and citrus, and created using three different sweeteners, including sucrose (natural and high caloric), stevia (natural and non-caloric), and sucralose (artificial and non-caloric). These sweeteners were selected to compare a classical, natural, and high-caloric sweetener and two non-caloric alternatives. Stevia was selected as a natural and emergent sweetener and sucralose as an artificial and widely used sweetener.

#### **2. Material and Methods**

#### *2.1. Chemicals and Reagents*

The standards used for quantification purposes, eriodyctiol (E), homoeriodictyol (HE), naringenin (N), and hesperidin (H) were purchased from TransMIT (Geiben, Germany). Formic acid and acetonitrile were obtained from Fisher-Scientific (Loughborough, UK). All solutions were prepared with ultrapure water from a Milli-Q Advantage A10 ultrapure water purification system (Millipore, Burlington, MA, USA).

#### *2.2. Juice Preparation and Characterization of the Phenolic Content*

Fresh dry organic maqui powder was provided by Maqui New Life S.A. (Santiago, Chile). Cítricos de Murcia S.L. (Ceutí, Spain) and AMC Grupo Alimentación Fresco y Zumos S.A. (Espinardo, Spain) provided the citrus juices. Sucrose was provided by AB Azucarera Iberia S.L. (Madrid, Spain), Stevia by AgriStevia S.L. (Murcia, Spain), and Sucralose by Zukan (Murcia, Spain).

For the manufacturing of maqui-citrus juices, maqui powder was mixed with citrus juices to obtain the base beverage. Then, the three selected sweeteners were added to obtain the different beverages characterized in the present work. The beverages underwent a pasteurization treatment by heating them at 85 ◦C for 58 s. Afterwards, the mixtures were bottled and stored at 5 ◦C until consumption by the volunteers.

The polyphenolic composition of the beverages was also characterized. With this objective, the juices were centrifuged at 10500 rpm for 5 min (Sigma 1–13, B. Braun Biotech International, Osterode, Germany). The supernatants were filtered through a 0.45 mm polyvinylidene fluoride (PVDF) filter (Millex HV13, Millipore, Bedford, MA, USA) and analyzed by RP-HPLC-DAD. The identification and quantification of flavanones was performed by applying a previously-used method [13,19]. Briefly, chromatographic analyses of the samples for the identification and quantification of flavanones were carried out in a Luna 5 μm C18(2)100 Å column (250 mm × 4.6 mm), using Security Guard Cartridges PFD 4 mm × 3.0 mm both supplied by Phenomenex (Torrence, CA, USA). The solvents used for the chromatographic separation were Milli-Q water/formic acid (95.0:5.0, *v*/*v*) (solvent A) and methanol (solvent B), with a linear gradient (time (min.), %B) (0, 15%); (20, 30%); (30, 40%); (35, 60%); (40, 90%); (44, 90%); (45, 15%); and (50, 15%), using an Agilent Technologies 1220 Infinity Liquid Chromatograph, equipped with an auto-injector (G1313, Agilent Technologies) and a Diode Array Detector (1260, Agilent Technologies, Santa Clara, CA, USA). Chromatograms were recorded and processed on an Agilent ChemStation for LC 3D systems. The volume of injection and flow rate were 10 μL and 0.9 mL/min, respectively. The quantification of flavanones was done on UV chromatograms recorded as hesperidin at 280 nm and expressed as mg per 100 mL of juice.

#### *2.3. Experimental Design*

A double-blind, randomized, cross-sectional clinical study was conducted on overweight people (*n* = 20). The study and protocol were approved by the official Ethical Committee of Clinical Studies (CEIC) of the General University Hospital Morales Meseguer (Murcia), and registered at ClinicalTrials.gov (NCT04016337). The volunteers provided written consent to participate in this study. The criteria for the volunteers' selection for the study were to be in good health, overweight (between 24.9 and 29.9 kg/m2 following WHO criteria), aged 40–60 years, non-smokers, non-dyslipidemic and normotense, with no chronic illnesses and not taking any medication. After an initial wash-out phase of 3 days with a strict diet free of polyphenols and added sugars, 330 mL of the test drinks (stevia, sucralose, and sucrose as the added sweetener) were administered on fasting conditions. Urine samples were collected 24 h prior (0 point), as well as in the following intervals: 0–3.5 h, 3.5–12.0 h, and 12.0–24.0 h. After 15 days, the process was repeated again, with the volunteers ingesting another drink developed with the remaining sweetener, until all the drinks were consumed by all the volunteers (3 rounds). The urine samples collected were stored at −80 ◦C until analysis. The analysis was performed once each period was finished and in the same batch to minimize analytical variations.

The total volume of each urine interval was recorded to calculate the absolute amounts of the compounds and metabolites excreted in the study period. Also, creatinine content was determined to normalize the concentrations of metabolites in urine as μg compound/mg creatinine, to control for differences in urine volumes.

#### *2.4. Urine Samples Collection, Processing, and Analysis by UHPLC-ESI-MS*/*MS*

Urine samples were defrosted and diluted 1:2 (*v*/*v*) in MilliQ-water/formic acid (99.9:0.1, *v*/*v*) and centrifuged at 15,000× *g* for 10 min, at 5 ◦C (Sigma 1–16, B. Braun Biotech International, Osterode, Germany). Afterwards, supernatants were filtered through 0.45 μm PVDF filters (Millex HV13, Millipore, Bedford, MA, USA) and stored at −20 ◦C until analysis by Ultra-High Performance Liquid Chromatography ElectroSpray Ionization Mass Spectrometry (UHPLC-ESI-MS/MS).

The identification and quantification of flavanone metabolites was performed by applying the method previously reported by Medina et al. with some modifications [20]. The analysis of samples on the profile and concentration of anthocyanin metabolites was carried out on with an Ascentis Express F5 column (5 cm ×2.1 mm; 2.7 μm) (Sigma, Osterode, Germany). The solvents used for the chromatographic separation were Milli-Q water/formic acid (99.9:0.1, *v*/*v*) (solvent A) and acetonitrile/formic acid (99.9:0.1, *v*/*v*) (solvent B), with a linear gradient (time (min.), %B) (0, 10%); (1, 10%); (10, 60%); (11, 80%); (13, 80%); (13.01, 10%), and (14.50, 10%); using an UHPLC system coupled with a triple quadrupole tandem mass spectrometer model 6460 (Agilent Technologies, Waldbronn, Germany), operating in multiple reaction monitoring (MRM) and negative/positive electrospray ionization (ESI) modes. The volume injected and flow rate were 10 μL and 0.2 mL/min, respectively. The MS parameters, at the optimized conditions, were gas temperature 325 ◦C; gas flow 10 L/min; nebulizer 40 psi; sheath gas heater 275 ◦C; sheath gas flow 12; capillary voltage 4000–5000 V; Vcharging 1000–2000. Data acquisition and processing were performed by using MassHunter software version B.08.00 (Agilent Technologies, Walbronn, Germany).

#### *2.5. Statistical Analysis*

Quantitative data are presented as mean ± SD of 20 volunteers. Specific differences were examined by an analysis of variance (ANOVA) and a multiple range test (Duncan's test). The data were processed using the SPSS 21.0 software package (SPSS Inc., Chicago, IL, USA.) and the level of significance was set at *p* < 0.05.

#### **3. Results and Discussion**

#### *3.1. Flavanone Content of Juices*

In order to establish the rate of urinary elimination of flavanones present in the maqui-citrus juices manufactured using three separate sweeteners (stevia, sucralose, and sucrose), their flavanones profile and concentration in juices were measured. In this regard, the presence of four flavanones was observed, which were found in the following decreasing concentration in all juices, H-rutinoside (4.87 mg/100 mL, on average) > N-rutinoside (1.31 mg/100 mL, on average) > E-rutinoside (0.32 mg/100 mL, on average) > N-hexoside derivatives (0.14 mg/100 mL, on average). As shown in Table 1, no significant differences were observed between the flavanone content of the maqui-citrus juices developed using diverse sweeteners either when considering individual or total flavanones.

**Table 1.** Flavanones composition of the maqui-citrus juices developed using diverse sweeteners.

Z N, naringenin; E, eriodyctiol; H, hesperetin. N.s., sot significant.

#### *3.2. Qualitative Analysis of Urine Metabolites of Flavanones from Maqui-Citrus Juice*

To profile the metabolites of flavanones excreted in urine, 24-h urine collected after the ingestion of 330 mL of maqui-citrus juice by healthy volunteers were processed, allowing for the evaluation of the differences due to the sweetener employed in the development of the juices (stevia, sucralose, and sucrose). The analysis results show that the urine samples exhibited 16 diverse phenolic metabolites, derived from the list of flavanones present in the juices and shown in Table 2. More specifically, the compounds identified in the urine samples were E, E-glucuronide, E-sulfate, E-disulfate, HE, HE-glucuronide, HE-diglucuronide, HE-sulfate, HE-glucuronide-sulfate, N, N-glucoside, narirutin, N-glucuronide, N-diglucuronide, N-sulfate, and N-glucuronide-sulfate. Interestingly, neither H, nor its

phase II derivative, were detected, although H was the main flavanone in the maqui-citrus based beverages, accounting for 73.3% of the total flavanones, on average.

**Table 2.** Qualitative analysis of flavanone metabolites in urine after the ingestion of maqui-citrus juices.

C.E., collision Energy; N.f.—not found; R.T., retention time.

Since the metabolism of the precursors of flavanone metabolites is closely dependent on the metabolic traits of the volunteers and the inter-individual variation [21], a range of metabolites (E, E-disulfate, HE, HE-diglucuronide, and HE-glucuronide-sulfate) was found in urine of a reduced number of volunteers. These compounds were present in quantifiable amount but the limited number of volunteers excreting these molecules indicates that these were not representative. The inter-individual variation could also be responsible for the dispersion of the concentration of the metabolites, making difficult the identification of significant differences relative to the quantitative determinations. On the contrary, E-glucuronide, E-sulfate, HE-glucuronide, HE-sulfate, N, N-glucoside, narirutin, N-glucuronide, N-diglucuronide, N-sulfate, and N-glucuronide-sulfate were identified and quantified in the urine from all volunteers.

#### *3.3. Quantification of Flavanone Metabolites in Urine Samples*

In urine, the quantification of the flavanone metabolites excreted was based on basal urine (0 h), as well as on urine excreted between 0 and 3.5 h, 3.5–12.0 h, and 12.0–24.0 h. The excretion kinetics for E and N matched, showing the highest concentration at 3.5 h after the intake of the beverages (Figure 1). For this reason, all the concentrations described below referred to 3.5 h after the ingestion. In the case of HE derivatives, no significant increases in the urine concentration was found.

**Figure 1.** Content (mean ± SD, *n* = 2) of single flavanone metabolites in basal urine and 3.5, 12, and 24-h urine of healthy volunteers after ingesting 330 mL of maqui-citrus juices developed using as sweeteners stevia (-), sucralose (O), and sucrose (Δ). Significantly different bioavailabilities according to an analysis of variance (ANOVA) and Duncan's multiple rank test were found at *p* < 0.001 (\*\*\*).

The sum of E and their phase II conjugates excretion provided values of 0.18 μg/mg creatinine in volunteers ingesting the beverages developed using sucralose as the sweetener. This concentration was higher than the one reached when using stevia and sucrose. The beverages developed using the latter sweeteners showed a 9.9% lesser amount of excretion than sucralose, on average. However, despite the trend observed, the large variation between volunteers did not allow for providing significant differences [21].

As mentioned above, the other flavanone metabolites present in urine in quantifiable concentrations were the N derivatives (Figure 1). The sum of N and their phase II derivatives excretion values was 115.91 μg/mg creatinine for sucralose, resulting in 12.2% and 32.1% lower amounts than sucralose, respectively, of stevia and sucrose-sweetened juices. When analyzing the effect of the sweetener in regard to the individual compounds, for N-diglucuronide, N-glucuronide-sulfate, and N-sulfate, the highest value corresponded to juices developed using stevia as a sweetener, which gave rise to 1.45, 1.69, and 19.74 μg/mg creatinine concentrations, respectively. Indeed, these concentrations significantly surpassed the urinary excretion reached when juices sweetened with sucralose and sucrose were ingested, by 33.3% (N-diglucuronide), 38.9% (N-glucuronide-sulfate), and 25.3% (N-sulfate), on average. In respect to N-glucuronide, the highest value corresponded to sucralose (93.71 μg/mg creatinine), which significantly surpassed the urine concentration provided by stevia and sucrose (25.2% lower, on average).

Moreover, stevia was the sweetener that provided a higher urinary excretion for most compounds derived from N (N-diglucuronide, N-glucuronide-sulfate, and N-sulfate), followed by sucralose (N-glucuronide). Sucrose did not provide remarkable higher rates of elimination through urine of any compounds in comparison with sucralose or stevia, as intestinal sugar carriers may play an important role in flavonoid absorption [22].

The results suggested that both stevia and sucralose were better than sucrose in terms of urinary excretion. Several studies of the effects on human health and metabolic diseases of stevia and sucralose showed contradictory results, as extensively reviewed by Daher et al. This author indicated that most intervention studies have assessed the role of isolated non-nutritional sweeteners and not as part of a habitual diet [23]. Thus, further studies are needed to learn more about the influence of stevia and sucralose on human health.

#### **4. Conclusions**

The results of the present work evidence that processing in respect to the selection of sweeteners does not seem to have any effect on flavanone concentration. On the other hand, the absorption rate of flavanones from citrus, excluding H, as they pass through the digestion system, is achieved through the formation of a variety of phase II derivatives. The results obtained pointed out sucralose and stevia as the sweeteners that had the greatest urinary excretion of N and most of its metabolites, which constitutes, as far as demonstrated responsible for valuable biological activities, a very useful marker for establishing the actual biological and healthy potential of the juices developed. Actually, they significantly surpassed the urinary excretion provided by sucrose that could be related with a variety of impacts of the diverse sweeteners on the actual bioavailability of flavanones. However, sucrose did not provide a higher urinary excretion as compared to sucralose or stevia in any of the cases.

This information would allow designing further studies of dietary interventions aimed at evaluating such sweeteners, which have gained relevance for human health. Indeed, considering the differences on urinary excretion between sweeteners, this study proposes two non-caloric sweetener alternatives (sucralose and stevia) in order to reduce the consumption of sucrose, a high caloric sweetener with an evident influence on metabolic disorders (type 2 diabetes and obesity, among others). Nevertheless, more studies are needed in order to better understand the effects on health of the two alternatives.

**Author Contributions:** Sampling, analytical determination, data processing, and drafting, V.A.; Experimental design, drafting, and supervision of the final version of the manuscript, R.D.-P.; Data analysis and revision of the final version of the manuscript, D.A.M.; Selection and management of volunteers and determination of urine creatinine, P.Z.; Supervised the project, designed the beverage formula, and contributed to the final version of the manuscript upon critical revision of the texts, C.G.-V. All authors have read and agreed to the published version of the manuscript.

**Acknowledgments:** This work was partially funded by the Spanish MINECO through Research Project AGL2016-75332-C2-1-R. VA was supported by a FPI grant (BES-2017-079754). The authors thank the English expert reviewer (Mario Fon) for the revision of the English style and grammar.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

*Article*


**4. Conclusions**

To summarize, patient selection and motivation to do periodontal therapy is the key to start host modulation therapy. Moreover, medical status of the patient would affect the outcome of the treatment.


**3. Conclusion**

In this chapter about rectal cancer there is content about rectal anatomy in relation to magnet-resonance imaging and TME- surgery (total mesorectal excision). There is a detailed description of imaging strategies concerning neoadjuvant and adjuvant radiotherapy and chemotherapy for rectal cancer patients. The staging and choice of treatment for rectal cancer are the main goal of any national and international organization in choosing guidelines and resp. guideline. The main guidelines are those of the European Society of Medical Oncology (ESMO), the European Rectal Cancer Consensus Conference (EURECCA-CC2) and the National Comprehensive Cancer Network (NCCN), but they also differ in their recommendations in some aspects of rectal cancer management.


**4.2 Population status**

The status of amphibians' population globally shows a serious declining trend, and 41% of 6638 known world's amphibian species are threatened with extinction [27, 28].  The class Amphibia are under the division of vertebrae animals and are classified into three orders namely; Order Caudata (salamanders and newts – not found in sub-Saharan Africa), Order Anura (frogs and toads) and Order Gymnophiona (caecilians). Taxonomically, the amphibians in East Africa are classified into two orders: the order Gymnophiona which includes the caecilians- whose members have annuli that resembles earth worms with moist and shiny skin and do not have legs. They occur globally within the tropics and in east Africa, two families occur. Their habitat is mainly buried in damp soil within forests biome. The second order is the anura whose members are mainly toads and frogs. The order comprises of tailless amphibians mainly frogs. Over 20 families of frogs have been documented globally and 8 families occur in East Africa. Relatively few tadpoles (40%) from East African frogs have been described. About 194 frog species and 9 caecilians have been documented in East Africa [30] and over 100 species in Kenya [7]. Although most of these species occur elsewhere in Africa, about 20 are endemic to Kenya [8]. The largest of the species in Kenya is the huge African Bullfrog, *P. edulis*, who inhabit areas around Tsavo National Parks and can weigh over 1 kg and Snout-Vent Length (SVL) is over 14 cm while the smallest species is the Unguja Puddle Frog, *Phrynobatrachus ungujae* who weigh less than 2 g and its SVL is only 1.6 cm [7].


**Preface to "Laws and Emerging Technologies"**

The emergence of new technologies of knowledge in all fields, their dissemination, and their application for social or economic benefit are essential activities for the progress of society worldwide. Its development has been essential for international economic and social convergence. However, the regulation and legal implications of these new technologies need to be addressed in the legal systems of every country.

> **Esther Salmer ´on-Manzano** *Editor*


**ELECTROPOLYMERIZATION**

Edited by **Ewa Schab-Balcerzak**

**INTECHOPEN.COM**

http://dx.doi.org/10.5772/1119 Edited by Ewa Schab-Balcerzak

#### **Contributors**

Milica Gvozdenović, Branimir Jugović, Jasmina Stevanović, Tomislav Trišović, Branimir Grgur, Yasushiro Nishioka, Hu Xiao-Ya, Xu Qin, Hao Shi-Rong, R. N. N. Singh, Madhu Chemicals, Rahul Awasthi, Laurent Ruhlmann, Delphine Schaming, Hao Jian, Clémence Allain, Jun Xia, Rana Farha, Michel Goldmann, Yann Leroux, Philippe Hapiot, Lai Chen, Xianfu Li, Jinliang Sun, Marie-Bernadette Villiers, Christophe Marquette, Arnaud Buhot, Carine Brakha, Patrice N. N Marche, Luz Maria Torres Rodríguez, Montes Rojas Antonio, Luna Zavala Israel Luis, López -Cázares Irene, Ramos Guzman Olivia Berenice, Nasser Arsalani, Amir Mohammad Goganian, Gholam Reza Kiani, Mir Ghasem Hosseini, Ali Akbar Entezami, El-Said Sayyah, A.B. Khaliel, R.E. Ebaid Azooz

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**3. CEDaCI—A Circular Economy for the Data Centre Industry**

The particular and diverse challenges of the data centre industry are unique and require an innovative whole systems approach to instigate major change because decisions made and actions taken at each life cycle stage affect the sustainability of all other life cycle stages. The Circular Economy for the Data Centre Industry (CEDaCI) project was initiated to kick start this change; it was developed and executed by academics and consultants from several different disciplines (including product and engineering design, social and behavioural sciences, business and life cycle management, and materials science), with knowledge of, but working outside, the sector, which is helping them to overcome these challenges. The project includes around 20 partners based in North West Europe; it is led by London South Bank University and other main partners include Operational Intelligence (UK), WeLOOP, TND and TEAM2 (France), GreenIT Amsterdam and SDIA (Netherlands), and Wuppertal Institute for Climate Environment and Energy (Germany). The project structure is underpinned by respected and proven methods for innovation, namely Design Thinking and the Design Council's Double Diamond process. Both methods also support a whole systems approach, which is critical to the development of any circular economy, and in particular, that within fragmented sectors.


*3.1. Phase Solubility Studies*

The phase solubility studies evidenced a linear increase of drug solubility with increasing CDs concentration (AL type), as reported in Figure 1. The results indicate, in all cases, the formation of soluble complexes of probable 1:1 mol:mol stoichiometry [18]. The parameters, reported in Table 1, evidenced the difference in the solubilizing and complexing power towards HCT among the different CDs.

**Figure 1.** Phase solubility diagrams of HCT with βCD(-), HPβCD (Δ), HEβCD (-), SBEβCD (X), and RAMEB (). Each value represents the mean of 9 measurements.

**Table 1.** Stability constant (K1:1), complexation efficiency (CE), and solubilizing efficiency (SE) of complexes of the different examined cyclodextrins (CDs) with hydrochlorothiazide in pH 5.5 phosphate buffer at 25 ◦C.

a ratio between drug water solubility in presence of the highest CD concentration used (12.5 mM for βCD and 25 mM for other CDs) and alone.

Our results were in full agreement with those of Onnainty et al., 2013 [25], who reported the same type of phase-solubility diagrams for HCT complexation with βCD. The highest values of complex apparent stability constant (K1:1), complexation efficiency (CE), and solubilizing efficiency (SE) were obtained with RAMEB and SBEβCD that gave rise to an approximately five-fold increase in drug solubility as compared with the drug alone (Table 1). The better performance of these derivatives can be attributed to the presence of methyl and sulfobutylether substituents which extended the CD hydrophobic region and improved substrate binding via a hydrophobic effect, as just observed for other lipophilic drugs [16,26].


**5. Conclusion**

*4.4.3. Plasmacytic hyperplasia PTLD*

*4.4.4. T-cell lymphoma PTLD*

*4.4.5. Relapses*

190 Heart Transplantation

autograft.

**4.5. Cell therapy**

This rare form of early lesions can be treated with radiotherapy or lymphoma chemotherapy.

**Figure 5.** Response of a monomorphic diffuse large B cell PTLD after four rituximab and after four R-CHOP.

This type of PTLD has a very poor prognosis, rituximab is useless and the classic chemotherapy-type CHOP has little effectiveness. In case of localized form, radiotherapy may be useful.

Relapses after complete remission are rare; if they occur late after the first PTLD, a comparison of the clones is necessary because a second PTLD, independent of the first one, is possible; if it is the case, the algorithm of first line, describes previously, can be reused, and the maximum dose of anthracycline will not be reached. In other cases, NHL treatments of immunocompetent patients in relapse may be used, even hematopoietic stem cell

Cell therapy is not yet available outside study protocols. Its principle is to use T cells specifically directed against EBV antigens, so it is only applicable to half of PTLDs. It is mostly the allogeneic lymphocyte banks, from healthy donors, that are promising. The lymphocytes are selected according to the HLA typing of the tumor. In the Scottish experience, 12 PTLDs are a clearly defined entity, representing the most increased cancer among cardiactransplant recipients compared to the general population. Its management, from preemptive treatment to curative treatment, has been considerably improved in order to obtain a survival rate similar to that of other transplant recipients. The treatment deviates significantly from that of immunocompetent lymphomas and requires management by teams accustomed to this type of pathology, both for the follow-up of the transplant and for the hematological treatment. The development of cell therapies is very likely the next step in progress.


**3. Numerical model and contact parameters estimation**

The diagrams summarized in **Table 1** and shown in **Figures 5** and **6a** are represented together with the corresponding simulated counterpart, obtained using the numerical model shown in **Figure 3b**. 3 The numerical model represents the damper inside the test rig, however the same numerical routine can be incorporated into a code which substitutes the test rig presence with that of a FE bladed system [35].

3 The springs representing the tripod and the mechanical structure hosting the piezo actuators have been experimentally measured as described in [39].

Only in-plane motion is addressed here (typical of blades bending modes, where dampers are most effective), however a more general 3D version of the same model is available for more complex cases. The general equilibrium equation to be solved at this stage is:

$$\text{[M]} [\text{\color{red}{Ul}}] + \text{[K]} [\text{\color{red}{Ul}}] = \text{ \color{red}{\{F\_c\}} + \text{[T]} \{F\_c\}} \tag{1}$$

where with reference to **Figure 3b**, [*M*] = *diag*(*mD*, *mD*, *mD*, *mLP*, *mLP*, *mRP*, *mRP*), [*K*] = *diag*(0, 0, 0, *k uL*, *k wL*, [*k* ′ *R*]) with [*k* ′ *R*] = [ *k* ′ *uR* cos2 *α* + *k* ′ *wR* sin2 *α* (*k* ′ *uR* − *k* ′ *wR*)sin*α*cos*α* (*k* ′ *uR* − *k* ′ *wR*)sin*α*cos*α k* ′ *uR* sin2 *α* + *k* ′ *wR* cos2 *α*] , {*U*} = {*uD*, *wD*, *βD*, *uLP*, *wLP*, *uRP*, *wRP*}, {*FE*} = {0, −*CF*, 0, *k uL* ∙ *uvol*, *k wL* ∙ *wvol*, 0, 0}, {*FC*} = {*TR* , *NR* , *TL*1 , *NL*1 , …,*TLnC* , *NLnC*} and [*T*] is a transformation matrix. In detail, vector {*FC*} is the output of the contact elements which are fed by the correct relative displacements at the contact.

In this chapter, Direct Time Integration [40] is used to avoid approximations, however should a larger system be considered, multi-Harmonic Balance Method can be applied [35].

The reader will notice that the damper is modeled as a rigid body, a quite reasonable assumption given the bulkiness of the damper.

The contact elements here applied are state-of-the-art in the gross slip regime [11], which is the focus of this chapter's investigation. The nonconforming contact (cylinder-on-flat) is modeled using one element, while the conforming contact requires at least two contact elements (four in **Figure 3b**). Increasing the number of contact elements will smoothen the hysteresis shape but not change significantly the damper behavior. The position of the contact points is typically set at equal intervals along the flat interface using the two edges as limits (i.e. starting and ending points).

## **3.1. Definition of the unknowns**

in **Figure 3c**). Each quantity is equipped with a proper level of uncertainty. Measurement uncertainty, minimized through a purposely developed protocol, ensures significant trust-

**Figure 5.** Measured vs. simulated. (a) T/N force ratio diagram. (b) Platform-to-damper hysteresis cycle at the flat-on-flat contact. (c) Moment vs. rotation diagram. (d) Platform-to-platform hysteresis cycle. Measured: dotted line, simulated:

The diagrams summarized in **Table 1** and shown in **Figures 5** and **6a** are represented together with the corresponding simulated counterpart, obtained using the numerical model shown in

numerical routine can be incorporated into a code which substitutes the test rig presence with

The springs representing the tripod and the mechanical structure hosting the piezo actuators have been experimentally

The numerical model represents the damper inside the test rig, however the same

**3. Numerical model and contact parameters estimation**

worthy results (error up to 7%).

solid line. IP case, with CF = 4.65 kg.

106 Contact and Fracture Mechanics

that of a FE bladed system [35].

**Figure 3b**.

3

3

measured as described in [39].

In principle, friction is a material property, therefore all interfaces, both conforming and nonconforming, should share the same contact parameter values. Friction is indeed a material property at microscopical level, therefore if a reliable and validated "realistic" model was available one could start from material properties and surface characteristics, and integration over the contact area would do the rest. However, since the selected contact elements are of the "heuristic" kind, other factors influence kn, kt and μ values.

In detail previous experience has shown that the geometry of the contact surface (line vs. area contact), contact surface kinematics and normal load play a significant role [37]. The influence of normal load will be addressed in Section 4, while, in order to take into account the influence of the contact areas different geometries and kinematics, it holds:

$$\begin{array}{ll} \mathbf{k}\_{\text{nK}} \neq \mathbf{k}\_{\text{nL}} \\ \mathbf{k}\_{\text{tK}} \neq \mathbf{k}\_{\text{tL}} \\ \mu\_{\text{g}} \neq \mu\_{\text{L}} \end{array} \tag{2}$$

for a total of six unknowns (also represented in **Figure 3b**).

Contact parameters of the flat-on-flat interface are typically distributed uniformly among the contact points, for example, considering the normal contact spring:

$$\mathbf{k}\_{\rm hL} = \frac{\mathbf{k}\_{\rm nL}}{\mathbf{n}\_{\rm c}} \tag{3}$$

The distribution of the normal contact stiffness at the flat-on-flat interface per unit length dknL/dx is obtained by linking the damper inclination (i.e. rotation angle βD at a given instant in time) to the position of the left contact force resultant NL. In other words, it is postulated that forces (i.e. moments) and displacements (i.e. rotation) are linearly linked. The technique also relies on two assumptions: (1) the normal contact stiffness is uniformly distributed along the flat interface (see Eq. 3 and **Figure 6b**); (2) the force per unit length q(x) related to the normal component of the left contact force resultant NL has a linear distribution. In detail, with reference to **Figure 6b**, let us define a reference system x, parallel to the contact with its origin in O, the mid-point of the flat interface. As shown in **Figure 6a**, the normal component of the left contact force resultant NL travels along the flat surface during the cycle. If, however NL enters the inner third portion of the flat interface (see **Figure 6c**) the complete surface is in

Modeling Friction for Turbomachinery Applications: Tuning Techniques and Adequacy…

dx *L*3 \_\_

This relation is graphically represented in **Figure 5c**, where the shaded are corresponds to the

All experimental evidence shown and commented in this chapter has been represented together with its simulated counterpart for validation purposes. Some of the features of the diagrams (i.e. T/N levels during slip stages and slopes of the hysteresis cycles during stick stages) are meant to be similar because they are used as a calibration key in the contact parameter estimation process. Other features such as force trajectories and left contact force resultant application point (**Figure 6a**); the platform-to-platform hysteresis cycle (e.g. **Figure 5d**); the transition between contact states and the time instant at which they take place (e.g. **Figure 5a**); are not part of the calibration process. Therefore, the goodness of fit of these observed and simulated signals is a further proof of the soundness of the model and of the correctness of the

portion of the cycle during which NL enters the inner third portion of the flat interface.

**4. Contact parameters variability and contact model adequacy**

**Table 3** and will be further commented on in the following subsections.

The purpose of this section is to detail the level of uncertainty of each of the contact parameters estimated in Section 3.2 and to investigate their variability. Results are summarized in

**Contact parameter μR ktR (N/μm) μL ktL (N/μm) dknL/dx (N/m2**

Uniform flat contact uncertainty bands [0.6–0.75] [25–35] 0.45–0.5 [20–30] [0.8–1.2] × 1010 Irregular flat contact uncertainty bands [0.6–0.75] [25–35] 0.45–0.6 [20–100] [0.4–1.2] × 1010

Normal load dependence No No Yes Yes Yes

**Table 3.** Uncertainty bands and normal load dependence of contact parameters obtained at CF = 4.65 kg.

12 βD (4)

http://dx.doi.org/10.5772/intechopen.72676

109

**)**

contact. Under this condition, the following holds:

M = NL ∙ x = d k\_\_\_\_nL

**3.3. Remark on experimental evidence and validation**

contact parameters used to calibrate it.

The validity of this assumption will be further assessed in Section 4.

#### **3.2. Step-by-step contact parameter estimation procedure**

Contact parameters are estimated starting from the experimental evidence, organized into diagrams as summarized in **Table 1**. In detail, for a given experimental nominal condition:

**Table 2.** Experimental contact states identification strategy.

The distribution of the normal contact stiffness at the flat-on-flat interface per unit length dknL/dx is obtained by linking the damper inclination (i.e. rotation angle βD at a given instant in time) to the position of the left contact force resultant NL. In other words, it is postulated that forces (i.e. moments) and displacements (i.e. rotation) are linearly linked. The technique also relies on two assumptions: (1) the normal contact stiffness is uniformly distributed along the flat interface (see Eq. 3 and **Figure 6b**); (2) the force per unit length q(x) related to the normal component of the left contact force resultant NL has a linear distribution. In detail, with reference to **Figure 6b**, let us define a reference system x, parallel to the contact with its origin in O, the mid-point of the flat interface. As shown in **Figure 6a**, the normal component of the left contact force resultant NL travels along the flat surface during the cycle. If, however NL enters the inner third portion of the flat interface (see **Figure 6c**) the complete surface is in contact. Under this condition, the following holds:

$$\mathbf{M} = \mathbf{N}\_{\mathrm{L}} \cdot \mathbf{x} = \frac{\mathrm{d} \, \mathrm{k}\_{\mathrm{nl}}}{\mathrm{d} \mathbf{x}} \, \frac{\mathrm{L}^3}{12} \beta\_{\mathrm{D}} \tag{4}$$

This relation is graphically represented in **Figure 5c**, where the shaded are corresponds to the portion of the cycle during which NL enters the inner third portion of the flat interface.

#### **3.3. Remark on experimental evidence and validation**

Contact parameters of the flat-on-flat interface are typically distributed uniformly among

Contact parameters are estimated starting from the experimental evidence, organized into diagrams as summarized in **Table 1**. In detail, for a given experimental nominal condition:

**Step 1.** Reference points on the diagrams in **Figure 5** have been marked by a symbol and a number: they are useful to guide the analysis of the cycle through cross-comparison.

**Step 2.** The cross-comparison of the T/N diagram (**Figure 5a**) and of the observed relative

displacement at the contact interfaces can be used to make a hypothesis on the contact states experienced by the damper during one period of vibration. Namely, if, during a given portion of the cycle, the T/N force ratio is constant and the relative displacement at the contact is non-negligible, then that interface is assumed to be in slip condition. On the other hand, if the T/N force ratio is varying and the corresponding displacement at the contact is negligible, the damper is likely to be stuck to the platform. This allows the user to assign each stage of a cycle a given contact state (see **Table 2**). **Step 3.** Based on the results of **Table 2**, friction coefficients at the right (cylinder-on-flat) and

left (flat-on-flat) interface, μR and μL, are estimated using the time history of the cor-

(referring to the stages identified as being in stick condition) can be used to estimate

 **(μm) Contact state T/N slope ΔtL (μm) Contact state**

, where τ is the time variable.

**Step 4.** Based on the results of **Table 2**, the slopes of the platform-to-damper hysteresis cycles

**Step 5.** The normal contact stiffness at the cylinder-on-flat interface knR is estimated using Brandlein's formula [28]. To this purpose only material properties and length of contact are needed. The new inserts equipped with contact "tracks" described in Section

nC

(3)

the contact points, for example, considering the normal contact spring:

The validity of this assumption will be further assessed in Section 4.

respondent T/N force ratio during slip (see **Figure 5a**).

**Right interface Left interface**

*t RD* (*τ*3) − *t RP* (*τ*3) ) − ( *t RD* (*τ*2) − *t RP* (*τ*2) )

1U–2 High ~1 Stick High 1.8 Stick 2–3 High <0.2 Stick Medium 7.8 Partial slip 3–4D Low 21.3 Slip Low 13.1 Slip 4D–5 High −0.6 Stick High −1.7 Stick 5–1U Low −21.7 Slip Low −21.03 Slip

tangential contact stiffness values (ktR and ktL).

2.2 ensure a controlled length of contact.

**1**

**Stage T/N slope ΔtR**

ΔtR of stage, for example 2–3, is defined as (

**Table 2.** Experimental contact states identification strategy.

1

**3.2. Step-by-step contact parameter estimation procedure**

knLi = k\_\_\_nL

108 Contact and Fracture Mechanics

All experimental evidence shown and commented in this chapter has been represented together with its simulated counterpart for validation purposes. Some of the features of the diagrams (i.e. T/N levels during slip stages and slopes of the hysteresis cycles during stick stages) are meant to be similar because they are used as a calibration key in the contact parameter estimation process. Other features such as force trajectories and left contact force resultant application point (**Figure 6a**); the platform-to-platform hysteresis cycle (e.g. **Figure 5d**); the transition between contact states and the time instant at which they take place (e.g. **Figure 5a**); are not part of the calibration process. Therefore, the goodness of fit of these observed and simulated signals is a further proof of the soundness of the model and of the correctness of the contact parameters used to calibrate it.


**2. Electromagnetic spectrum**

 Electromagnetic waves propagate at different frequencies. The electromagnetic spectrum is the classification of the waves in accordance to their range of frequencies. The classification is necessary since waves which radiate at different frequencies may be generated by different sources and may exhibit different effects on matters. The names given to the bands of frequencies may be broadly classified, in the order of decreasing wavelength and increasing energy and frequency, as follows:

*Introductory Chapter: Electromagnetism DOI: http://dx.doi.org/10.5772/intechopen.85155*

(v) ultraviolet radiation

(vi) X-rays

(vii) gamma rays

A summary of the spectrum is given in **Figure 2**. It is to be noted that the frequencies at each edge of the band are merely approximations. The boundaries of each band are difficult to be defined since the waves are continuous and the bands may fade into each other.


**1. Introduction**

The large-scale exploitation of fossil fuels has had important environmental repercussions such as climate change or the rise in sea level amongst others [1,2]. This means that there is currently a need to reduce the dependence on fossil fuels and place greater emphasis on renewable energy sources in order to fulfil future sustainable energy needs [3,4]. In 2009, the European Union (EU) established that 20% of final energy consumption should originate from renewable sources by 2020 [5], and additionally set 2050 as the target year by which emissions will have been reduced by 80% [6,7]. In this context, and with the aim of achieving a sustainable development, in 2015, the United Nations Framework Convention on Climate Change was established in order to reduce the causes of climate change as regards food production and limit the increase in temperature (increases of up to 1.5 ◦C) [8]. A number

of viable renewable energies could, therefore, be exploited to achieve this goal, among which marine renewable energy (MRE) is attracting increased attention [9].

MRE is currently recognized as being an abundant, geographically diverse energy resource that has both the public's acceptance and positive associated externalities (economic growth, job creation or the mitigation of the negative impacts of climate change, etc.) [10]. It can be exploited from offshore wind, waves, tides, tidal currents, thermal gradients or salinity gradients. This paper is focused on the exploitation of the tidal current resource, which it is hoped will play a major role in meeting future energy needs with regard to other renewable energy sources thanks to its high predictability, stability and high load factor [11]. If we wish to employ technologies to harness the energy obtained from tidal currents in order to attain sustainable development, it is necessary to use natural resources in an efficient manner, i.e., we must optimize their exploitation [12]. Devices that can be utilized to harness tidal current power where the depth is no greater than 40 m have been developed by various technology manufacturers [13,14]. These devices, which are denominated as first generation tidal energy converters (TECs), are normally supported on bases that are fastened to the seabed by means of various types of anchoring systems (monopole, piloted or gravity). It is undoubtedly technically feasible to employ these devices to harness energy from tidal currents, although very few tidal stream projects are currently operating at a commercial stage [15]. This is principally owing to the fact that it typically costs more to generate energy from tidal currents than it does when using other renewable technologies [16]. It is consequently vital to understand the parameters that may affect the cost structure in order to provide a framework containing areas in which these costs can be reduced [17].

A detailed analysis of the life cycle costs (LCC) for first generation tidal energy farms (TEFs) shows that the installation and maintenance procedures are of the utmost importance and must be optimized in order to increase their current potential, help their acceleration and sustainability and help attract investment in these technologies [18,19]. These procedures include the transportation of each of the TECs from the base port to its installation site, the preparation of the seabed, the placement and installation of anchor systems and/or the deployment of a mooring system, and the positioning, connection and disconnection of the main units of the devices [20,21]. These tasks necessitate the use of special high-performance ships that are equipped with dynamic positioning, large cranes, etc., and this implies high installation and maintenance costs [22,23]. The installation and maintenance costs are greatly dependent upon the accessibility and reliability of the device [16]. It would, however, be possible to increase system performance and decrease the aforementioned costs by automating the performance of the immersion and emersion maneuvers [24,25]. This can be done by controlling the ballast water inside the devices, which consequently permits the implementation of a closed loop depth and/or orientation control that makes(s) it possible to: (i) raise the generation unit from the seabed to the surface of the sea and (ii) carry out the same operation but in reverse. We can perform these automatic maneuvers by using small guide wires and by controlling the ballast water inside the device. The achievement of this objective will consequently influence: (i) less human intervention, (ii) the possibility of using the cheapest general purpose ships rather than high cost special vessels for maintenance purposes, (iii) a reduction in the number and duration of installation and maintenance operations or (iv) an increase in the competitiveness of these technologies, among others. The potential benefits of these systems are very important, but, as they are in an early stage of development, studies that address the economic feasibility of these systems have not yet been developed. Several authors have produced interesting papers comprising feasibility studies concerning other types of offshore projects. These include: wind energy [26], wave energy [27], co-located projects (wind and wave energy) [28] and hybrid projects (wind and wave energy) [29]. No economic-financial studies focusing on the automation of installation and maintenance maneuvers have, however, been produced to date.

The main contributions of this research are the following: (i) we discuss the merits of automated installation and maintenance maneuvers with regard to manual maneuvers for an idealized gravity (a substantial mass is used to support the structure on which the TEC is placed.) -based first generation TEC designed by our research group (Grupo de Investigación Tecnológico en Energías Renovables

Marinas, *GIT-ERM*); (ii) we provide interesting information about manual and automated installation and operation maneuvers for these tidal energy technologies, which is not usually found in scientific literature as these technologies are at an initial (pre-commercial) stage of development, and (iii) we carry out a comparative economic-financial feasibility study for these maneuvers, which illustrates that the development of advanced automation systems for these maneuvers may be a very interesting approach by which to increase the competitiveness of this source of renewable energy in the near future.

The remainder of the paper is organized as follows: Section 2 describes the procedures used to carry out installation and maintenance maneuvers for first generation TECs in both a manual and an automated fashion. The procedure used to evaluate the economic-financial feasibility of tidal energy projects using manual or automated maneuvers is briefly explained in Section 3. Section 4 shows the results attained after carrying out a numerical case study of a 50 MW TEF in the cases of both manual and automated maneuvers. Finally, Section 5 is devoted to our conclusions and proposals for future works.


**7. Conclusion**

Pulmonary hypertension and its most dreaded consequence, RV dysfunction, are important mortality risk factors in cardiac surgery. Accordingly, all cardiac patients may benefit from early diagnosis and/or treatment prior to the surgical procedure. In patients with PH, further evaluation of potential alterations in the RV function would be relevant. Thus, future trials should prioritize in-depth exploration of preventive approaches in order to address the role of preemptive reduction of PH severity before cardiac surgery and to determine its impact on postoperative outcomes and survival improvement.


*Edited by John Stanton and Rosa Caiazza*

This book provides a comprehensive overview of the food chain and related issues, especially in lesser developed countries where supply chain problems and issues in the agribusiness sector are most dramatic. Each chapter provides the reader with an important perspective on the value chain either in local markets or in well-developed markets. The lessons learned from this book are pertinent to any aspect of the supply chain and to any country whether it be fully or lesser developed.

> *Usha Iyer-Raniga, Sustainable Development Series Editor*

> > ISBN 978-1-83768-511-0

Agricultural Value Chains - Some Selected Issues

ISSN 2753-6580

Published in London, UK © 2023 IntechOpen © Andre2013 / iStock

## IntechOpen Series Sustainable Development, Volume 7

## Agricultural Value Chains Some Selected Issues

*Edited by John Stanton and Rosa Caiazza*