Compendious Discourse Concerning MANET Routing Protocols & Simulation Tools

Now a days, Mobile Ad Hoc network is the most trendy topic for researchers. Mobile Ad Hoc network is infrastructure less wireless network that is made up of different mobile devices that creates link with other nodes on the fly and also changes their links between nodes more frequently. This type of network is more useful when one wants to get connected with some nodes for a particular session and does not wants to create a dedicated link for all the time. This paper entitles the brief discussion about MANET, various Routing protocols used to route data between these nodes. The purpose of this study is to provide the brief knowledge about MANET network. Moreover, this study entitles some of the simulation tools used in analyzing the performance of the Mobile Ad Hoc Network

Exploring the role of glycosylation in vascular biology, immunology,and stem cell biology

Carbohydrates are important modulators in various biological and physiological processes. They are present ubiquitously and coat all cells, forming the glycocalyx of the cell. Glycosylation, a type of post-translational modification (PTM), is an enzymatic process of addition of carbohydrates to lipids and proteins leading to the formation of an abundant and diverse repertoire of glycoconjugates. These glycoconjugates participate in many key biological processes including cell adhesion, molecular trafficking and clearance, receptor activation, signal transduction, and immunomodulation. Carbohydrate-based or -modified therapeutics are becoming increasingly attractive due to their potential roles in angiogenesis and immunomodulation. However, their mechanisms of action in different biological models are not fully explored. In this thesis, three different studies were undertaken to investigate the influence of glycosylation and its importance in different biological cell systems. These studies were aimed at understanding the influence of glycosylation of osteopontin (OPN) in vascular biology, investigating a panel of poly- and oligo-saccharides as potential immunomodulators, and exploring the alteration of extracellular matrix (ECM) components produced in response to variable oxygen concentration in stem cell culture. In Chapter 2, OPN was investigated for its influence on angiogenic functions. OPN is a glycoprotein that upon pre- incubation with endothelial progenitor cells (EPCs) enhances the therapeutic benefit of EPCs after transplantation in a mouse model of hind limb ischemia. It is a pleiotropic molecule with diverse PTMs, including glycosylation and phosphorylation. It binds to a subset of integrin receptors activating intracellular pathways but the roles of PTMs in OPN towards its biological activities are not known. This study investigated the effect of PTMs on OPN for its functional activity using human umbilical vein endothelial cells (HUVECs) as a cell model system. OPN produced in various expression systems, including murine NS0 (rhOPN), bovine milk (bOPN), human breast milk (hOPN) and bacteria (eOPN), were digested with endo- and exo-glycosidases and characterised for their differential PTMs. The digestion studies confirmed the absence of N-linked oligosaccharides on OPN molecules, presence of varied degrees of O-linked oligosaccharides and absence of phosphorylation on all molecules, except bOPN and the absence of PTMs on eOPN. The functional activities of bOPN, rhOPN and their glycoforms along with eOPN were compared to a control, i.e HUVECs incubated without OPN. OPN prolonged the lifetime of tubules, secretion of angioenic factors and increased cell proliferation. It also led to increased activity of p-PI3K- AKT signaling pathway. However, no significant differences were reported between the glycoforms and phosphoforms of OPN, which suggested no significant roles for OPN glycosylation and phosphorylation in these biological functions. In Chapter 3, natural poly- and oligo-saccharides were assessed as potential immunomodulators. Natural polysaccharides offer relatively low toxicity, negligible side effects and ease of accessibility over conventional drugs for immunodulation. These test compounds were characterised for their molecular and physical properties. Upon incubation of human whole blood culture (HWBC) and a monocytic cell line, THP-1, with lipopolysaccharide (LPS) and six oligo- and poly-saccharides (inulin, galacturonan, heteroglycan and fucoidan, mannan and xyloglucan), the supernatant was screened for secreted cytokines and chemokines. TNF-α was measured by flow cytometry in HWBC cell sub-populations. Of the six oligo- and poly-saccharides, inulin, galacturonan, heteroglycan and fucoidan demonstrated pro-inflammatory properties in addition to LPS, while mannan and xyloglucan did not elicit any significant responses. Intracellular TNF-α expression was also increased in the monocytes of HWBC in response to inulin, galacturonan, heteroglycan and fucoidan. This study highlighted inulin and heteroglycan as potential immunomodulatory therapeutics and demonstrated HWBC to have a greater and more varied response in comparison to THP-1 cell, suggesting that HWBC may be a better model than single monocytic cell line to screen test compounds. In Chapter 4, the glycomic and proteomic constituents of mouse stromal cell MS-5 secreted ECM under normoxic and hypoxic conditions were analysed. MS-5 is a feeder cell line that produces ECM that acts as sticky basement for the survival and maintenance of undifferentiated state of hematopoietic stem cells grown above it. When cultured under hypoxic conditions, MS-5 cells improve transcription of pluripotency genes and certain genes involved in mesenchymal cell lineage commitment and their differentiation potential. However, the roles of ECM components in this beneficial effect are not known. To investigate differentially expressed ECM components produced under normoxia and hypoxia, ECM was prepared under normoxic (21% O2) and hypoxic (2% O2) conditions by feeder cells. In silico analyses led to the identification of proteins enriched in each condition and their associated biological functions. Of the identified proteins, 50% of the proteins were found to be ECM-related where they participate in ECM-receptor interactions, focal adhesion and leucocyte transendothelial migration pathway. Based on the abundance of glycosylation related proteins and glycosyltransferases from in silico analysis, a panel of lectins with appropriate specificities were selected for histochemistry of intact ECM in situ. Lectin blotting for the total proteome indicated increased sialylation, fucosylation and mannosylation in hypoxic proteins compared to normoxic. The identified proteins and glycosylation related proteins could be exploited in the development of biomaterials and bioactive scaffolds in the field of tissue engineering. In addition to the above studies, small projects are presented in appendices. In Appendix 1, human OPN was cloned, expressed and purified in bacterial system to obtain OPN devoid of any PTMs. In Appendix 2, the natural oligo- and polysaccharides presented in Chapter 3 were also tested for their angiogenic and antiangiogenic properties using HUVECs and angiogenesis related functional assays were performed. In Appendix 3, a statistical analysis for the lectin microarray profiling data of bovine milk fat globule membrane is presented. With an interdisciplinary approach, diverse roles of carbohydrates were explored using different biological cell models. The studies described in this thesis helped to clarify the roles of PTMs, natural polysaccharides and environmental conditions towards the vascular biology, immunology and stem cell biology. These studies also provided the future directions for further elucidation or study of these molecules towards exploring their therapeutic properties. This thesis hence, provided an opportunity to integrate the field of glycobiology, that was once studied on its own, into the field of therapeutics, immunology and stem biology and utilising the available tools in each field

ROLE OF SERUM LIPIDS IN GALLSTONE PATHOGENESIS: A CASE–CONTROL STUDY FROM PUNJAB

  Objective: Pathogenesis of gallstone (GS) disease is multifactorial, involving both genetic and environmental factors. The main pathogenic factor responsible for the hypersecretion of cholesterol into bile is the impaired lipid metabolism, which actually reflects the likelihood of GS formation. The study aims to determine the significance of serum lipids in the etiology of GS disease and to identify the possible confounding effects of age, gender, and body mass index (BMI) on GS disease.Methods: A case–control study was conducted on 97 ultrasonically confirmed GS cases and 92 healthy controls which were further divided on the basis of gender, age group (≥40 and <40 (y)), BMI (obese and non-obese), and number of stones (single and multiple). The serum lipid parameters were estimated using the enzymatic kit assay. The statistical analysis of the lipid parameters in relation to age, gender, obesity, and stone number was done using the Student's t-test, Chi-square test, and Mann–Whitney U-test. p<0.05 was considered statistically significant.Results: The mean serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were significantly higher in cases as compared to controls (p=0.0001 [95% confidence interval [CI]: 33.3–61.2] and p=0.0001 [95% CI: 36.6–64.2], respectively). The serum high-density lipoprotein cholesterol (HDL-C) level was non-significantly lower in GS patients as compared to controls (p=0.4). Obese female patients of age group ≥40 (y) had an abnormal lipid profile with a significant rise in mean TC, LDL-C, and triglycerides (TG) (p<0.05) and were at higher risk of developing the GS disease as compared to controls. However, no probable effect of abnormal lipid profile, age, gender, and BMI on increasing the number of stones was found (p>0.05).Conclusion: Abnormal lipid parameters, especially high TC and LDL-C, were found to be significantly associated with GS disease. Increased age, obesity, and female gender along with dyslipidemia altogether elevate the risk of formation of GS. The formation of single/multiple stones was not influenced by the abnormal lipid profile, age, gender, and BMI

Identification of a putative corticosteroid in Pacific Lamprey (Entosphenus tridentatus)

The mechanisms and interplay of multiple axes as well as the physiological components of the stress response have been studied in many vertebrate groups; however, the intricacies and chemical messengers involved in the stress response in lamprey have not been fully resolved. 11-Deoxycortisol is a functional corticosteroid in sea lamprey, but the identity of the functional corticosteroid used by other lamprey species and the evolution of the stress response in lamprey lineage remains unknown. Identification of the functional corticosteroid in a greater number of lamprey species will help elucidate the evolution of the stress response in lamprey. I have demonstrated that 11-deoxycortisol, a steroid precursor to cortisol, may be a functional corticosteroid in Pacific lamprey. The putative hormone was identified in Pacific lamprey plasma by employing an array of methods such as radioimmunoassay (RIA), high performance liquid chromatography (HPLC) and mass spectrometry analysis. I have demonstrated that plasma levels of 11-deoxycortisol significantly increased in Pacific lamprey 0.5 and 1 hr after stress exposure and that sea lamprey corticotropin releasing hormone (CRH) injections increased circulating levels of 11-deoxycortisol, suggesting that 11-deoxycortisol secretion is under control of the hypothalamic neuropeptide CRH. However, plasma 11-deoxycortisol concentrations did not increase in response to sea lamprey adrenocorticotropic hormone (ACTH) injections. The effect of artificially elevated 11-deoxycortisol on the expression of glucocorticoid receptor and progesterone receptor mRNA was examined in liver, gill, muscle, heart and testis using RT-qPCR. 11-Deoxycortisol was chronically elevated using coconut oil implants with two different doses of 11-deoxycortisol (0.5 and 1.0 µg per g of body weight). After 7 days of elevated plasma 11-deoxycortisol concentrations there was no significant difference in the expression of either receptor in the tissues examined. Overall, the results of this thesis demonstrate 11-deoxycortisol is a putative corticosteroid in Pacific lamprey; however, despite the evidence for hypothalamic control of 11-deoxycortisol release, the results do not conclusively support Pacific lamprey having a hypothalamic pituitary interrenal (HPI) axis.Science, Faculty ofZoology, Department ofGraduat

Evaluation of DNA damage in agricultural workers exposed to pesticides using single cell gel electrophoresis (comet) assay

Background : Pesticides are used in agriculture to protect crops, but they pose a potential risk to farmers and environment. The aim of the present study is to investigate the relation between the occupational exposure to various pesticides and the presence of DNA damage. Materials and Methods : Blood samples of 210 exposed workers (after a day of intense spraying) and 50 control subjects belonging to various districts of Punjab (India) were evaluated using Comet assay. Sixty workers who showed DNA damage were selected for follow up at 5-6 months after the first sampling during a low or null spraying period. Results : Significant differences were found in DNA damage between freshly exposed workers and controls and freshly exposed and followed up cases. There was significant increase in the comet parameters viz. mean comet tail length and frequency of cells showing migration in exposed workers as compared to controls (72.22 ± 20.76 vs. 46.92 ± 8.17, P<0.001; 31.79 vs. 5.77, P<0.001). In the second samples, followed up cases showed significant decrease in frequency of damaged cells as compared to freshly exposed workers of first sampling (P<0.05). The confounding factors such as variable duration of pesticide exposure, age, smoking, drinking and dietary habits etc which were expected to modulate the damage, were instead found to have no significant effect on DNA fragmentation. Conclusion : The evidence of a genetic hazard related to exposure resulting from the intensive use of pesticides stresses the need for educational programs for agricultural workers to reduce the use of chemicals in agriculture

Evaluation of DNA damage in agricultural workers exposed to pesticides using single cell gel electrophoresis (comet) assay

Background : Pesticides are used in agriculture to protect crops, but they pose a potential risk to farmers and environment. The aim of the present study is to investigate the relation between the occupational exposure to various pesticides and the presence of DNA damage. Materials and Methods : Blood samples of 210 exposed workers (after a day of intense spraying) and 50 control subjects belonging to various districts of Punjab (India) were evaluated using Comet assay. Sixty workers who showed DNA damage were selected for follow up at 5-6 months after the first sampling during a low or null spraying period. Results : Significant differences were found in DNA damage between freshly exposed workers and controls and freshly exposed and followed up cases. There was significant increase in the comet parameters viz. mean comet tail length and frequency of cells showing migration in exposed workers as compared to controls (72.22 \ub1 20.76 vs. 46.92 \ub1 8.17, P&lt;0.001; 31.79 vs. 5.77, P&lt;0.001). In the second samples, followed up cases showed significant decrease in frequency of damaged cells as compared to freshly exposed workers of first sampling (P&lt;0.05). The confounding factors such as variable duration of pesticide exposure, age, smoking, drinking and dietary habits etc which were expected to modulate the damage, were instead found to have no significant effect on DNA fragmentation. Conclusion : The evidence of a genetic hazard related to exposure resulting from the intensive use of pesticides stresses the need for educational programs for agricultural workers to reduce the use of chemicals in agriculture

Photoredox reactions of methylene blue on zinc oxide

729-732Photoreduction of methylene blue (MB+) at 366 nm (3.4 eV) in a heterogeneous medium containing ZnO (band separation = 3.2 eV) has been carried out. In oxygen-free media the product has been found to be leuco-MB which is fully converted into MB+ on air oxidation. An analysis of the results shows that Zno is the absorber and negligible light absorbed by MB+ cannot explain the observed conversions. Concentration of ZnO in the medium plays a more important role at higher concentrations of MB+. Also reaction extent decreases with increase in dye concentration but at low concentrations it is proportional to dye concentration. A unique feature of the reaction is that it is quenched by the product. Photoreduction is more efficient in solvents of high dielectric and in solvents with easily available hydrogens. Different samples of ZnO prepared from different salts behave differently in this photoreduction due to different reflectance and absorbance characteristics of these samples. A mechanism explaining the observed data and consistant with the known features of such systems have been proposed

Modelling and Computational Analysis of Piezoelectric Micro-cantilever based Switch

Abstract In this paper, study about the Piezoelectric MEMS (Micro-Electro-Mechanical Systems