**4. Vermicomposting**

contained 24 plots (2 crops × 3 replicates × 4 treatments). The treatments were (1) SS amended with soil, (2) CM amended with soil, (3) horse manure (HM, **Figure 3**) amended with soil, each at 15 t acre-1, and (4) no‐mulch bare soil used for comparison purposes. The results in **Table 1** revealed that soil amended with SS increased plant biomass production in arugula and mustard by 26 and 21%, respectively, compared to no‐mulch (NM) native bare soil [24].

162 Organic Fertilizers - From Basic Concepts to Applied Outcomes

**Figure 3.** Horse manure obtained from Kentucky horse park, College of Agriculture, University of Kentucky, Lexing‐

**Soil amendment Root weight, g Shoot weight, g Plant weight, g**

SS 74.24 a 290.95 a 365.20 a HM 54.00 b 247.21 b 301.21 b CM 41.64 c 235.60 c 277.23 c NM 30.08 c 240.45 c 270.54 c

SS 61.43 b 426.60 a 488.00 a

ton, Kentucky, USA.

**Arugula**

**Mustard**

In agricultural practices, vermicomposting is the product or process of composting worms, usually red wigglers, white worms, and other earthworms such as *Eudrilus eugeniae* to create a heterogeneous mixture of decomposing vegetable or food waste and animal bedding materials to promote biotransformation of organic waste into organic fertilizer and contribute to sustainable agricultural practices. Researchers, government agencies, and farmers are seeking new ways to manage and utilize agricultural wastes to beneficial use. This way of environmental management could be used as a green technology to bio‐covert plant residues or animal manure residues into nutrient rich in organic fertilizers [29]. Many factors such as available moisture, particle size, and organic content contribute to the growth of earthworms [30]. Earthworms might lose weight and die if they are fed with materials such as rice residues that are rich in lignin, even if the substrate is fortified with nitrogen‐rich amendments to decrease the initial C/N ratio [31]. According to Edwards [32], the basic principle in earthworm breeding systems is to regularly add small batches of wastes in the composting chamber to allow worms to process successive layers of waste.

Data revealed that earthworm growth was lower in treatments that contained high percentages of cow dung (CD). Results also showed that *E. eugeniae* growth was reduced when the proportion of CD in feed substances was increased. This could be due to the earthworm preference of feed substances that may favor rice straw (RS) than CD, and possibly due to inadequate control of ammonia volatilization, resulting from inadequate pre‐treatment of cow manure to remove urea present in the initial material.  This is because of the high sensitivity of earthworms to ammonia and presence of high concentrations of cations in livestock manure. Accordingly, availability of pre‐treated cow manure could be used to enhance the reproduction and growth of *E. eugeniae* for use in composting and organic agricultural production.


**3.  For a better understanding,

in this chapter, some of these processes will be exemplified to illustrate the roles of EVs in intercellular communication.

#### **3.1 Implantation and embryonic development**

The implantation process refers to the development of the trophoblasts by the embryo, which then will adhere and invade the uterine wall. This is a crucial step in embryonic development, and any inaccuracy can have severe consequences [2]. EVs are secreted by both maternal and embryonic cells. In the first case, studies have shown that endometrial epithelial cells produce EVs that stimulate the activation of focal adhesion kinase (FAK), increasing the adhesion of trophoblasts to the uterine wall [52]. Regarding embryonic production of EVs, recent studies have shown the involvement of MVs. Laminin and fibronectin, two extracellular matrix proteins, found on the surface of MVs, are playing an important role in this case. MVs are transported to trophoblasts, where laminin and fibronectin activate integrins on the surface of the trophoblast, stimulating the activation of c-Jun N-terminal kinase (JNK) and FAK and thus promoting migration of trophoblastic cells and rates of implantation [53]. Embryonic development is influenced by communication between the cells of embryos, through the secretion of factors that are still not well known. Some studies have suggested that EVs could be involved in these processes. For example, a study conducted by P. Qu *et al*. on bovine cells has shown that embryos without replaced culture medium contain CD9 positive exosomes and have a better chance of a healthy pregnancy [54]. Another study conducted by I.M. Saadeldin *et al*. concluded that EVs are influencing the communication between embryos. They combined cloned embryos with embryos from an unfertilized egg cell and showed that the latter are secreting CD 9 positive exosomes and EVs containing RNA transcripts that encoded some pluripotency genes, improving the features of the cloned embryos if co-cultured [55].

The roles of the EVs in implantation and embryonic development are illustrated in **Figure 3**.

#### **3.2 Cancer development**

EVs are produced by stromal cells, which can be found, along with cancerous cells, as components of a tumor mass. In this case, EVs act like a bidirectional transferring mechanism between stromal cells and cancerous cells, influencing tumor evolution [6]. The biogenesis, release pathways, and the contents of EVs will be modified by the tumor microenvironment. Circulating DNA, contained by EVs will be transferred between apoptotic bodies (derived from apoptotic tumor cells) and other cells, leading to increased expression of oncogenes [56]. Tumor-derived EVs play a crucial role in all steps of cancer development, being more and more studied, to discover new treatment methods [57].

For a better understanding of the role of EVs in tumoral processes (cell proliferation, apoptosis resistance, angiogenesis, local invasion and metastasis, therapy resistance, etc.) we will discuss this with respect to some cancer types.

Some studies have shown that exosomes produced and released by ovarian cancer cells can carry RNAs and miRNAs, influencing cell transformation and tumor evolution. RNA-binding protein LIN 28, a marker of SCs, is associated with an unfavorable outcome when present in malignancies. Ovarian cancer cells which express high LIN 28 levels can secrete exosomes, which can further interact with noncancerous cells, leading to variations of gene expressions and cell behavior. This can lead

#### **Figure 3.**

*The roles of the EVs in embryo communication. (A) The uterine epithelium secretes EVs that stimulate the adhesion of trophoblastic cells to the uterus; (B) embryonic stem cells (ESCs) produce EVs that stimulate the trophoblasts to migrate and implant into the uterus; (C) the co-culturing of embryos increases (*↑*) embryo development (D), mediated by EVs. Created with BioRender.com (last accessed on September 22, 2021).*

to consequential amplification of genes responsible for epithelial to mesenchymal transition, human embryonic kidney 293 cells (HEK 293) invasion, and migration [58]. SKOV3, an ovarian cancer cell line, is also involved in cancer development by producing and releasing exosomes that can stimulate the M2 macrophage phenotype and consequently migration and proliferation of cancerous cells [6].

In breast cancer, studies have shown that EVs contain two extracellular matrix proteins, discoidin I-like domains 3 and epidermal growth factor-like repeats, that can activate FAK cascade and, along with an independent mechanism of microRNA biogenesis possessed by EVs, they play a crucial role in cancer development [59, 60].

In glioblastoma, EVs are transferring between cells the protein chloride intracellular channel-1, which stimulates the growth of the recipient cells, and the splicing factor RNA-binding motif protein 11, which increases survival [61, 62]. Moreover, the effect of EVs on angiogenesis, an important process in tumor growth, has been studied on glioma cells and it has been reported that EVs contain factors that promote angiogenesis by stimulating vascular endothelial growth factors [63].

In bladder and gastric cancer and melanoma, EVs are releasing platelet-derived growth factor receptor-beta, which is stimulating PI3K/AKT and MAP/ERK pathways, thus increasing cell proliferation and apoptosis resistance [64, 65].

The role of the EVs in intercellular communication and cancer development occurs not only locally but also remotely, leading to metastatic disease. The most studied components of EVs involved in this process are miRNAs that can influence angiogenesis, local invasion, colonization, immune modulation, etc., and annexin II, *Extracellular Vesicles as Intercellular Communication Vehicles in Regenerative Medicine DOI: http://dx.doi.org/10.5772/intechopen.101530*

a membrane-associated protein, by stimulating angiogenesis [66, 67]. Also, peritoneal metastases of ovarian cancer are accelerated by matrix metalloproteinase-1 from EVs [68].

Therapy response in cancer can be influenced by EVs, until the emergence of multidrug resistance, by transferring some drug resistance traits from cancer cells to recipient cells, like drug efflux pumps (decreasing drug concentrations in the cells by drug efflux), apoptotic regulators (simulating anti-apoptotic pathways), proteins involved in metal ion transportation (decreasing the effect of a metal-based therapy, as cisplatin), but also microRNAs, functional mRNAs and lncRNAs (long non-coding RNAs) [57, 69–71].

#### **3.3 Therapeutic potential of EVs**

As already mentioned, EVs have an important role in cell-cell communication and thus in physiological and pathological processes, leading to an increased interest in studying their ability to generate new therapeutic methods. Over time, several studies have tried to demonstrate the involvement of EVs in immunological modulation, tissue regeneration, bioengineering, transportation of therapeutic agents, etc. [4]. One focuses our attention on explaining some other therapeutic potential of EVs, while the role of EVs in tissue regeneration will be separately discussed.

One of the first studied therapeutic potentials of EVs has been in immunotherapy. EVs produced by mesenchymal stromal cells (MSCs), especially exosomes, can induce an M2-like phenotype (anti-inflammatory, regenerative) in monocytes *in vitro* and thus polarization of activated CD4 T-cells to regulatory T-cells [72]. Some experimental studies performed in rats have shown that allograft rejection can be decreased by regulatory T-cells (activated by exosomes) in kidney and intestinal transplantation in rats and by exosomes derived from immature dendritic cells in cardiac transplantation [73–75]. In ischemic events, MSCs are producing exosomes that are decreasing myocardial inflammation after 24 h, by secreting anti-inflammatory cytokines and MVs that are reducing renal inflammation and fibrosis [74, 75].


**1. Introduction**

254 Wireless Communications and Networks – Recent Advances

[14] John G. Proakis, "Digital Communications", McGraw-Hill Companies, Inc and publishing house of electronics industry, China. ,fourth edition, pp.766 , 2001. [15] Guosong Li, "Research on channel estimation in wireless OFDM systems", Ph.D thesis,

University of Electronic Science and Technology of China, 2005.

[17] MAXIM Integrated Products, Datasheet of MAX2828/2829, 19-3455, rev0, Oct. 2004 [18] F. M. Gardner, "Interpolation in digital modems – Part I: Fundamentals," IEEE Trans.

[19] F. M. Gardner, "Interpolation in digital modems – Part II: Implementation and performance," IEEE Trans. Commun., vol. COM-41, pp. 998-1008, Jun. 1993. [20] F. M. Gardner, "A BPSK/QPSK timing-error detector for detector for sampled receivers," IEEE Trans. Commun., vol. COM-34, pp. 423-429, May. 1986.

[16] IEEE P802.11n/D1.0, March 2006.

Commun., vol. 41, pp. 501-507, Mar. 1993.

The combination of multiple-input multiple-output (MIMO) antennas and orthogonal frequency-division multiplexing (OFDM) can achieve a lower error rate and/or enable highcapacity wireless communication systems by flexibly exploiting diversity gain and/or the spatial multiplexing gains. Such systems, however, rely upon the knowledge of propagation channels. In many mobile communication systems, transmission is impaired by both delay and Doppler spreads [1]-[7]. In such cases, explicit incorporation of the time-varying characteristics of mobile wireless channel is called for.

The coefficients of a linearly time-varying (LTV) channel can be usually modeled as uncorrelated stationary random processes which are assumed to be low-pass, Gaussian, with zero mean (Rayleigh fading) or non-zero mean (Rician fading) depending on whether line-of-sight propagation is absent or present [1][6]. Recently, the basis expansion models, i.e. the truncated discrete Fourier basis (DFT) models, polynomial models and discrete prolate Spheroidal sequence models, have gained special attentions, especially for the situation that channel is caused by a few strong reflectors and path delays exhibit variations due to the kinematics of the mobiles [1]-[2] [5]-[6] [16] [25]-[28].

In conventional pilot-aided channel estimation approaches, MIMO channels can be effectively estimated by utilizing the time-division multiplexed (TDM) and (or) frequencydivision multiplexed (FDM) training sequences [5]-[7] [20]-[23] [25]. Although the channel estimates are in general reliable, extra bandwidth or time slot is required for transmitting known pilots. In recent years, an alternative approach, referred to as superimposed training (ST), has been extensively studied in [8]-[19] [26]-[28]. In the idea of ST, additional periodic training sequences are arithmetically added to information sequence in time- or frequencydomain. The advantage of the scheme is that there is no loss in information rate, and thus enables higher bandwidth efficiency. However, some useful power must inevitably be allocated to the pilots, and thus resulting in information signal-to-noise ratio (SNR) reduction. Meanwhile, the information sequences are viewed as interference to channel estimation since pilot symbols are superimposed at a low power to the information sequences at the transmitter. The existing ST-based channel estimations are mainly restricted to the case where the channel is linearly time-invariant (LTI), where the channel transfer function can be estimated by using first-order statistics [8]-[13] [17]-[18]. In the latest contributions, J. K. Tugnait [16] extended the conventional ST to time-varying environment where the LTV channels are modeled by complex exponential bases. For the issue of training power allocation, the optimal pilot power has been investigated by [24] for different taps of low-pass filter, and then, the optimization of ST power allocation for LTI channel is mathematically analyzed based on equalizer design [15] [19].

In this paper, a new ST-based channel estimator is proposed for OFDM/MIMO systems over LTV multipath fading channels. The main contributions are twofold. First, the LTV channel coefficients modeled by the truncated discrete Fourier bases (DFB), unlike the existing approaches [1]-[2] [5]-[6] [16], cover multiple OFDM symbols. Then, a two-step channel estimation approach is adopted for LTV channel estimation. Furthermore, a closedform expression of the estimation variance is derived, which provides a guideline for designing the superimposed pilot symbols. We demonstrate by analytical analysis that the estimation variance, unlike that of conventional ST-based schemes [8]-[19], approaches to a fixed lower-bound as the training length increases. Second, for wireless communication systems with a limited transmission power, unlike [10] where the issue of ST power allocation is derived by optimizing the SNR for equalizer design, we provide an optimal solution of ST power allocation with a different point of view by maximizing the lowerbound of channel capacity. Comparatively, the training power allocation scheme [10] can be otherwise considered as a special case compared with the proposed approach. In simulations presented in this paper, we compare the results of our approach with that of the FDM training approaches [5] as latter serves as a "benchmark" in related works. It is shown that the proposed algorithm outperforms that of FDM training, and yields higher transmission efficiency.

The rest of the paper is organized as follows. Section II presents the system and channel models. In Section III, we estimate the LTV channel coefficients with the proposed two-step channel estimation approach. In Section IV, we derive the closed-form expression of the channel estimation variances. Section V determines the optimal ratio of the ST power to the total transmission power by maximizing the lower-bound of channel capacity. Section VI reports on some simulation experiments in order to test the validity of theoretic results, and we conclude the paper with Section VII.

*Notation:* The letter *t* represents the time-domain variable and *k* is the frequency-domain variable. Bold letters denote the matrices and column-vectors, and the superscripts[ ]*T* and [ ]*H* represent the transpose and conjugate transpose operations, respectively. , [ ]*k t* denotes the (*k*, *t*) element of the specified matrix.


**7. Conclusions**

In this paper, a novel SMBC method was proposed for the multi-point temperature control system. The controlled object was defined as a two inputs, two outputs temperature control system. A step-by-step introduction of the proposed control system was investigated. The system identification was carried out to obtain the transfer functions of the controlled objects, and the Ziegler–Nichols (step response) method was applied to the controller design. Simulation of the proposed SMBC control system was carried out in the MATLAB/SIMULINK environment, and the experiments were carried out with a DSP control platform. The effectiveness of the proposed SMBC method was verified by comparing the results to those for a conventional PI control system and gradient temperature system.


*4.1. Trend Analysis of the Influence of SMPs*

Figure 8 shows the interaction curves of the six SMPs with PM2.5 and wind speed. It also demonstrates that the effect of each SMP on PM2.5 concentration and wind speed has an inverse connection within a particular interval, but the outcomes of other intervals on PM2.5 concentration and wind speed are different.

**Figure 8.** Curve fitting of different morphological parameters with PM2.5 and wind speed: (**a**) BD; (**b**) GCR; (**c**) BED; (**d**) ABF; (**e**) ABV; (**f**) SDH.

According to Figure 8, wind speed is the most important element influencing PM2.5 dispersion, and high wind speeds promote pollution transport and dispersion. The spatial morphological characteristics of distinct neighborhoods define their internal wind environment under the same incoming wind speed conditions, which has an impact on the transport dispersion and concentration distribution of air pollutants. Furthermore, the different impact results are exhibited by the morphological parameters in different intervals. It is claimed that there are parameter intervals for each morphological parameter that are more positive (or less positive) to the transmission and dispersion of air contaminants.


**3.1 Graphdiyne**

Graphdiyne (GDY) is a new two-dimensional all-carbon allotrope composed of benzene rings and alkyne unites.

The carbon based nanomaterials are usually used to build electrochemical biosensors because of their physical and chemical properties. According to conventional carbon nanomaterials, GDY possesses richer carbon chemical bonds, which are of great importance for their practical applications. More importantly, GDY has a typical 2D structure similar to graphene, but also has the properties of threedimensional materials such as a hard carbon network and uniformly distributed pores that can greatly increase active bonding areas [19, 20].

**Figure 2** illustrates surface characterization of GDY [21].

As can be seen from this figure it is clear that GDY has a porous structure which is very important in sensor design to the effective diffusion of the analyte to the sensor surface.

**Figure 2.** *A) SEM, B) TEM and C) HRTEM of GDY.*

There are studies in which GDY has been used in the preparation of electrochemical enzyme biosensors [21], for microRNA testing [22] and in the determination of bacterium [23]. GDY was investigated as matrix for tyrosinase (a model enzyme) immobilization to create a mediator-free GDY based biosensor for rapid detection of bisphenol A (BPA). In this study between different carbon nanomaterial based biosensors including carbon nanotube and graphene was compared and it was reported, GDY-based tyrosinase biosensor performed better analytical for BPA detection than CNTs and graphene-based biosensors [21]. A new photoactive material has been synthesized that integrates the properties of MoS2 and GDY to implement ultra-sensitive detection of microRNA [22]. Controllable synthesis of two-dimensional graphite nanosheet (GDY NS) is of great importance for the clinical diagnosis and treatment of tuberculosis [23].

It is though that as a new promising 2D all-carbon nanomaterial after graphene, graphdiyne with intriguing properties would inevitably attract the general interest of scientists.