Doctor of Philosophy

dissertationInspired by the Sandcastle Worm, biomimetic of the water-borne adhesive was developed by complex coacervation of the synthetic copolyelectrolytes, mimicking the chemistries of the worm glue. The developed underwater adhesive was designed for sealing fetal membranes after fetoscopic surgery in twin-to-twin transfusion syndrome (TTTS) and sealing neural tissue of a fetus in aminiotic sac for spina bifida condition. Complex coacervate with increased bond strength was created by entrapping polyethylene glycol diacrylate (PEG-dA) monomer within the cross-linked coacervate network. Maximum shear bond strength of ~ 1.2 MPa on aluminum substrates was reached. The monomer-filled coacervate had complex flow behavior, thickening at low shear rates and then thinning suddenly with a 16-fold drop in viscosity at shear rates near 6 s-1. The microscale structure of the complex coacervates resembled a three-dimensional porous network of interconnected tubules. This complex coacervate adhesive was used in vitro studies to mimic the uterine wall-fetal membrane interface using a water column with one end and sealed with human fetal membranes and poultry breast, and a defect was created with an 11 French trocar. The coacervate adhesive in conjunction with the multiphase adhesive was used to seal the defect. The sealant withstood an additional traction of 12 g for 30-60 minutes and turbulence of the water column without leakage of fluid or slippage. The adhesive is nontoxic when in direct contact with human fetal membranes in an organ culture setting

Salivary amylase from Chilo partellus (Swinhoe) — Characterization and mode of inhibition through analysis of double reciprocal, fractional velocity and combination plots

The stem borer Chilo partellus (Swinhoe) is the most devastating pest that causes huge losses to agricultural productivity. Being a herbivorous insect, the starch degrading enzyme, salivary amylase, plays a crucial role in its digestive system. The characterization of salivary amylase and targeting it with potent inhibitors could help in managing the pest by hindering its normal digestive process. Therefore, we have made an attempt to characterize the enzyme and analyze its nature of interaction with organic acids and inorganic salts. The salivary amylase was purified by G-100 column chromatography to 16.02 folds and biochemically characterized. The purified fraction consisted of α-amylase activity with a single isoform of 59.26 kDa. It showed an optimum pH between 6.0 and 7.0. Its optimum temperature was 40 °C and was thermally stable up to 70 °C. Starch was the preferred substrate of salivary amylase. By critical analysis of Lineweaver-Burk, Eadie- Hofstee and Hanes plots, the Km and Vmax values of salivary amylase for starch were confirmed to be 0.49 mg/mL and 1.67 nmoles of reducing sugars formed/min/mL, respectively. Zinc chloride, calcium nitrate, salicylic acid, citric acid and oxalic acid were found to be potent inhibitors of salivary α-amylase activity. From Lineweaver-Burk, fractional velocity and combination plots, it was inferred that citric acid was a pure non-competitive inhibitor of salivary α-amylase while salicylic acid, oxalic acid and zinc chloride caused complete mixed non-competitive- competitive inhibitions. The inhibition of salivary α-amylase with calcium nitrate was of complete mixed non-competitive- uncompetitive type

Biochemical and nutritional characterization of chickpea (Cicer arietinum) cultivars

Thirty nationally released chickpea cultivars were evaluated for carbohydrate composition, soluble proteins, total lipids and anti-nutritional factors such as phenolic compounds, tannins, bound fructose of sucrose and raffinose family oligosaccharides, phytic acid, saponins, trypsin inhibitors and activities of enzymes related to them such as acid and alkaline phosphatases and a-galactosidase. Phytic acid showed a lot of diversity between cultivars and varied from 4.74-20.40 mg/g. Avrodhi, BG 256 and Virat were found to be nutritionally important as they had higher protein content (241.5 mg/g–261.5 mg/g) and starch content was found to be between 412.4 mg/g–485.5 mg/g. Avrodhi and BG 256 had lower content of tannin, phytic acid, saponin and trypsin inhibitors and the content of bound fructose of raffinose family oligosaccharides was found to be minimum in Avrodhi. Virat had the highest protein content among kabuli cultivars and it had lower amount of total phenols, flavonols, tannins and phytic acid. HC 1, BG 1053, Pant G 186 and PBG 1 had protein content between 200.0 mg/g–211.5 mg/g and had higher content of tannin, saponin, phytic acid and total phenols. Five cultivars namely HC 3, Vishal, ICCV 10, JG 315 and Saki 9516 had most of the anti-nutritional factors in medium content. Bound fructose of raffinose family oligosaccharides in kabuli cultivars were found to be in the range of 8.31-10.06 mg/g whereas in desi a lot of variation was observed and it ranged from 5.53 mg/g to 10.13 mg/g. All the cultivars were found to cluster in major four groups on the basis of principal component analysis. The result showed the diversity between nutritional and antinutritional factors in the cultivars that could be further used by plant breeders to develop superior genotypes

MS

thesisR-curve behavior of four different silicon carbide (SiC) materials was assessed using an indentation/strength technique. Two developmental grades, with similar microstructures and chemistries but different fracture modes, were compared with commercially available SiC-N (Cercom, Inc., Vista, CA) and solid-state PS-5000 (Morgan AM&T). The long-crack fracture toughness, measured using single-edge precracked beam (SEPB) technique, was 88% higher for material A (SEPB of 6.4 MPavm), which showed a highly intergranular fracture mode compared to B (SEPB of 3.4 MPavm), which was mainly transgranular. The higher SEPB toughness was associated with a modest increase in average strength (25%) and a significant increase in Weibull modulus (11 to 32). Short-crack fracture toughness measured with the indentation method used fracture strength and crack lengths at fracture to assess R-curve behavior. A new method for determining 6, which characterizes the residual driving force of the plastic zones based on stable growth of indentation cracks from the initial (co) to instability (c*) lengths, was developed. Material A exhibited a rising crack-growth resistance behavior compared to material B, which had mainly flat crack-growth resistance. Commercial SiC-N also showed R-curve behavior whereas PS-5000 had no Rcurve. The concept of a crack-stability map was developed for materials with R-curve behavior. Transformation-toughened Ce02 doped ZrC>2 (Ce-TZP) was shown fifteen years ago to have both R-curve behavior and high reliability. These data were revisited by considering the interaction between the crack-driving force and the rising resistance to such growth. Three distinct crack-growth regimes occur for this material. Unstable crack growth is followed by a region of stable crack growth, which leads to a second condition for unstable crack growth. Conditions for each of the three regions are discussed. Extremely high Weibull values (m>50) are possible for ceramic materials with large regions of stable crack growth. It is shown that the ratio of the fracture toughness at the initiation of crack growth (K0) to the steady-state fracture toughness (Kx) determines the behavior of materials with R-curve behavior. For materials like SiC, where Ko/Kx is greater than 0.197, it is nearly impossible to grow cracks from natural flaws because the cracks grow unstably. For Ce-TZP, however, since Ko/Kx is less than 0.197, a region of stable crack growth allows nearly invariant strength, which results in truly damage resistant ceramics

A poetic and sculptural negotiation of growing up as a Punjabi Sikh British woman encountering male bias.

In this Master’s by Research study, I look at the social dynamics of male bias in British Punjabi Sikh communities. Using myself as a case study, I draw out personal narratives to reflect on the impact that son preference can have on an individual. I have used an artistic practice-led methodology that entails sculpture and poetry as tools to encounter the emotional and psychological imprints that this bias has left on me. The artworks are also a means to manifest and reflect upon this confrontation outside my own body and mind. A significant part of this research is how to take the findings out into the wider community as the 3-D forms, whether text or sculpture, become transactive once in the public arena. One of the essential findings is that gender bias has affected me in multifarious ways. There is a disparity between the egalitarian normative ideas pertaining to Sikh philosophy and the operative beliefs practiced culturally1. Through this inquiry, I have also recognised the importance of looking at this issue on a personal level as it has inhibited my practice as an artist. It became apparent that just by depicting images of Sikh women in herstory, was not enough to engender empowerment and did not reflect egalitarian attitudes. What was curious to learn was a subjective inquiry using art was powerful in accessing the impact of this male bias and was a means that resonated with other girls and women, who like me, have suffered and are suffering the consequences of this gender bias in UK Punjabi Sikh communities

Adhesive complex coacervate inspired by the sandcastle worm as a sealant for fetoscopic defects

Inspired by the Sandcastle Worm, biomimetic of the water-borne adhesive was developed by complex coacervation of the synthetic copolyelectrolytes, mimicking the chemistries of the worm glue. The developed underwater adhesive was designed for sealing fetal membranes after fetoscopic surgery in twin-to-twin transfusion syndrome (TTTS) and sealing neural tissue of a fetus in aminiotic sac for spina bifida condition. Complex coacervate with increased bond strength was created by entrapping polyethylene glycol diacrylate (PEG-dA) monomer within the cross-linked coacervate network. Maximum shear bond strength of ~ 1.2 MPa on aluminum substrates was reached. The monomer-filled coacervate had complex flow behavior, thickening at low shear rates and then thinning suddenly with a 16-fold drop in viscosity at shear rates near 6 s-1. The microscale structure of the complex coacervates resembled a three-dimensional porous network of interconnected tubules. This complex coacervate adhesive was used in vitro studies to mimic the uterine wall-fetal membrane interface using a water column with one end and sealed with human fetal membranes and poultry breast, and a defect was created with an 11 French trocar. The coacervate adhesive in conjunction with the multiphase adhesive was used to seal the defect. The sealant withstood an additional traction of 12 g for 30−60 minutes and turbulence of the water column without leakage of fluid or slippage. The adhesive is nontoxic when in direct contact with human fetal membranes in an organ culture setting. A stable complex coacervate adhesive for long-term use in TTTS and spina bifida application was developed by methacrylating the copolyelectrolytes. The methacrylated coacervate was crosslinked chemically for TTTS and by photopolymerization for spina bifida. Tunable mechanical properties of the adhesive were achieved by varying the methacrylation of the polymers. Varying the amine to phosphate (A/P) ratio in the coacervate formation generated a range of viscosities. The chemically cured complex coacervate, with sodium (meta) periodate crosslinker, was tested in pig animal studies, showing promising results. The adhesive adhered to the fetal membrane tissue, with maximum strength of 473 ± 82 KPa on aluminum substrates. The elastic modulus increased with increasing methacrylation on both the polyphosphate and polyamine within the coacervate. Photopolymerized complex coacervate adhesive was photocured using Eosin-Y and treiethanolamine photoinitiators, using a green laser diode. Soft substrate bond strength increased with increasing PEG-dA concentration to a maximum of ~90 kPa. The crosslinked complex coacervate adhesives with PEG networks swelled less than 5% over 30 days in physiological conditions. The sterile glue was nontoxic, deliverable through a fine cannula, and stable over a long time period. Preliminary animal studies show a novel innovative method to seal fetal membrane defects in humans, in utero

An Efficient Method of Number Plate Extraction from Indian Vehicles Image

Automatic Number Plate Recognition (ANPR) is an imageprocessing technology that identifies vehicles by their number plates without direct human intervention. It is an application of computer vision and important area of research due to its many applications. The main process of ANPR is divided into four stages. This paper presents a simple and efficient method for the extraction of number plate from the vehicle image based on morphological operations, thresholding and sobel edge detection, and the connected component analysis

Status of phenolic metabolism and α-amylase inhibitor in maize under Chilo partellus infestation

The present study was aimed to determine the status of phenolic metabolism and α-amylase inhibitor in maize genotypes showing differential tolerance towards Chilo partellus infestation. The central whorl leaves and stems of the infested maize genotypes were collected at seven days interval from the day of infestation till 28 days of infestation. In general, the contents of phenolic compounds—total phenols, flavonols, o-dihydroxyphenols, tannins and the activities of phenylalanine ammonia lyase, tyrosine ammonia lyase, peroxidase and polyphenol oxidase were comparatively higher in the tolerant genotypes (PMH 3 and CM 500) as compared to the susceptible ones (PMH 1 and CM 139). The α-amylase inhibitor activity was higher in the central whorl leaves and stems of PMH 3 against both salivary and gut α-amylases of Chilo partellus, under control and infested conditions. It may be concluded that the higher content of phenolic compounds, induced activities of the phenol metabolizing enzymes and the high α-amylase inhibitor activity of tolerant genotypes against both salivary and gut α-amylases might be responsible for inducing resistance against Chilo partellus infestation

Human Security : conceptualising, reconciling, operationalising.

This dissertation examines human security vis-a-vis conceptualising, reconciling and operationalising the paradigm. It further explores the origins and development of the concept of human security by identifying the shortcomings in the literature, which lacks conceptual agreement. In order to resolve this conceptual debate, human security is defined as 'freedom from want'.Master of Science (International Relations

A STUDY ON POSITION BASED ROUTING FOR VEHICULAR NETWORKS

Survey of Position based routing Algorithms used in VANET