Master of Science

thesisThe dynamic strength properties of rock have a critical application in blasting, fragmentation, designing underground structures, and perforating oil and gas wells. This research focused on two types of sandstone from Utah with two different ranges of porosity and the effect of porosity and water content on dynamic compressive and tensile strength under dynamic loading conditions. The Split Hopkinson Pressure Bar (SHPB) apparatus was used for measuring the compressive and tensile strength of these rocks. The dynamic compressive strength, measured under a strain rate of about 350/s, was found to be 1.4 to 2.0 times the compressive strength measured under static conditions for samples of similar dimensions in both dry and saturated conditions for 'red' and 'buff' sandstones. Based on these results, this research found that rock specimens with higher porosity had a higher dynamic increase factor (DIF). In addition, water reduced the cohesion of saturated rock by approximately 20%, and saturation reduced the dynamic compressive and tensile strength by approximately 20%. However, fragment sizes of saturated samples are finer than those of dry samples. The saturated samples also absorbed approximately 15% less energy

Carbohydrate and lipid metabolism in insulin resistant states and the development of in vivo magnetic resonance spectroscopic techniques for the analysis of gluconeogenesis and glycogen synthesis

PhDThis thesis will provide new information on carbohydrate and lipid metabolic control in various related physiological states both in vitro and in vivo in the rat model. Pregnancy is one such state which elicits many complex changes both physiologically and metabolically, one major consequence of which is the development of insulin resistance/glucose intolerance by the mother. The aim was to evaluate the mother's capacity to utilise glucose during the various stages of pregnancy. For the first time, an unrestrained, unanaesthetised rat model was used to produce indices of glucose utilisation (GUI) in a wide range of tissue types ranging from non-working postural muscles to continually contracting muscles like the heart. In the various fed conditions investigated, significant reductions in the GUI of up to 80% were seen during late pregnancy in some tissues. A method of feeding was also applied to the pregnant model producing results contrary to normal pregnant glucose utilisation values ie. increasing the GUI up to 90% of normal pregnancy values in some tissues. Lipogenic rates in five major tissue sites were concurrently investigated which showed increases of between 2.2 and 4 fold during late pregnancy compared with virgin controls. Analysis of glycogen levels and an attempt to probe the pyruvate dehydrogenase activities of the heart and diaphragm in the various physiological states are also discussed. To obtain further insight into glycogen synthesis/non-oxidated disposal of glucose in the liver, a less invasive approach was then followed to explore, by non-invasive techniques, the extent to which insulin resistant states, like pregnancy, can be explained by in vivo hepatic glucose metabolic studies. For this, carbon-13 magnetic resonance spectroscopy (MRS) was employed to determine the fate of 1-13C glucose in the liver of rats in the same physiological states as those studied in the above methodology. Bolus infusions of 13C-glucose were administered into the hepatic portal vein of the rats under investigation. The incorporation or degradation of the glucose was followed in real time by observing rapid proton-decoupled carbon spectra. From this methodology, continuous real time glucose utilisation rates together with glycogen synthesis rates were measured. 13C incorporation into the glycogen macromolecule was seen to be negligible in 20 day pregnant ad libitum fed rats however in routine meal fed (RMF - allowed free access to food for 2h per 24h day) 20 day pregnant rats, incorporation reached a level 2.3 fold higher than the former. Maximal increases of 13C incorporation were shown by the 10 day pregnant RMF rats which attained levels 2.4 fold higher than the 20 day pregnant RMF group. Results indicate an enhancement of the direct route for glycogen deposition during RMF regimes in pregnancy. A consequence to the above MRS study led an investigation into gluconeogenic control in the rat model. Gluconeogenesis is a major metabolic pathway which may be perturbed in insulin resistant states like non-insulin dependent diabetes mellitus. In this study 13P MRS was employed as a tool to look at the relative changes in vivo of the hepatic phosphorus spectrum. This study involved external manipulation of hepatic gluconeogenesis by the infusion of alanine. Large increases in the phosphomonoester region of the phosphorous spectrum were seen both in vivo and in vitro which was secondary to increases in 3-phosphoglycerate. The inorganic phosphates also increased dramatically together with concomitant declines in ATP both of which recovered to pre-infusion values. This study shows many promising features which could be applied to clinical studies in humans

Stress relaxation in filamentous materials : The effect of humidity, temperature and strain on man-made fibres and silk

The relaxation of tension in strained filaments of Terylene, Perlon, Grilon, nylon 66, nylon 610, polyethylene, polypropylene and silk has been studied at strains up to 4% extension, at constant relative humidity of 65% and with humidity fluctuating between 35% and 90% r.h., and at constant humidity with the temperature varied from 2

Pharmacokinetic and pharmacodynamic evaluation of a single dose of new, first in world, high dose aqueous formulation versus conventional oil based preparation of cholecalciferol

Background: Vitamin D deficiency (VDD) is a common condition in India with prevalence in general population varying from 50-94%. VDD has been associated with increased susceptibility to a wide range of viral infections including COVID-19. It is associated with worse outcomes and greater morbidity and mortality in medical as well as surgical ICUs. The objective of the study was to evaluate the pharmacokinetic (PK)/pharmacodynamic (PD) of aqueous cholecalciferol injection in comparison with conventional oil-based injection in VDD healthy adult subjects. Methods: 24 eligible vitamin D deficient healthy adult males, fulfilling the inclusion/exclusion criteria, were enrolled in the study. Subjects received a single dose of either test (T) [Aqueous cholecalciferol injection 600K IU/2 mL] or reference (R) [Cholecalciferol 600K IU oil-based injection] intramuscularly. Various PK parameters (Cmax, AUC0-t, AUC0-∞ and Tmax) and PD parameters (concentration of cholecalciferol and 25(OH)D) were measured along with safety analysis. Results: A significantly higher concentration of cholecalciferol and 25(OH)D were observed with test product compared to reference (p<0.01) from 1-hour post-administration till end of the study. A statistically significant difference between test and reference product was observed for the calculated Cmax and Tmax for cholecalciferol and 25(OH)D (p<0.0001). All 12 (100%) subject in test arm achieved the normal level of 25(OH)D by 72 hr post-administration as compared to none in reference arm (p=0.0017). There were no serious adverse events (SAEs) or deaths reported during the study. Conclusions: This first in world, aqueous formulation of cholecalciferol injection was found to be superior in various PK/PD parameters as compared to conventional oil based injection, which resulted in rapid and sustained rise in serum 25(OH)D levels

Determination of the bioavailability and biodistribution of a single dose of oral cholecalciferol/Calcirol® soft gelatin capsule by pharmacoscintigraphy- CalSci study

Background: It is required to study the bioavailability and biodistribution of specific cholecalciferol formulation before prescribing. Pharmacoscintigraphy is an established radiological-imaging technique that is used to map various drug formulations as they traverses the human body (biodistribution) in real-time. We evaluated the bioavailability and biodistribution pattern, transit time, and gastrointestinal clearance of a single dose of Calcirol® soft gelatin capsule 60,000 IU [an oral cholecalciferol (vitamin D) formulation] using pharmacoscintigraphy. Methods: Six male healthy adult volunteers were administered a single oral dose of Calcirol® soft gelatin capsule labelled with technetium-99m. Post-dosing, serial venous blood samples were collected till day 27 for the estimation of the plasma levels of 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol levels. Different pharmacokinetic parameters were calculated. Sequential static gamma imaging was performed to evaluate the biodistribution of Calcirol® soft gelatin capsule. Descriptive statistics was used. Various pharmacokinetic parameters were calculated from the concentration-time curves. Statistical analysis was carried out using Student’s t-test. Suitable multivariate analysis was performed based on the distribution of data. All statistical analyses were performed using SAS® Software (v 9.4). Results: The overall absorption of Calcirol® soft gelatin capsule was 93.23%, which was fully from the small intestine. It led to achieving a sufficient level of 25-hydroxycholecalciferol (>60 ng/ml) within 6 hours of oral intake. The levels of plasma 25-hydroxycholecalciferol and 1,25-dihydroxycholecalciferol increased (maximum around 6 and 18 days, respectively). The small intestinal residence time was around 16 hours. No adverse event was noted. Conclusions: This was the first pharmacoscintigraphy study in the world which demonstrated the favourable bio-distribution of the Calcirol softgels supporting its role in vitamin D supplementation

Determination of sex from various measurements of human sternum and manubrium in Gujarat population

Background: Determination of sex from the skeletal remains is of immense importance in the field of forensic medicine, physical anthropometry and anthropology. Various previous studies have demonstrated sternum as an important tool for the determination of sex. Aims: Aim of the present study was to establish normal range of values for various dimensions of sternum in the studied population and evaluate the sexual dimorphism in the sternum. Material & Methods: The present study was conducted at M.P. Shah Govt. Medical College, Jamnagar on Computed tomography scans of a total of 83 adult Gujarati individuals (57 males, 26 females). Various sternal and manubrial linear measurements and indices were measured and analyzed. Results: It was found in the study that manubrial length, sterna length, manubrial width and combined length of manubrium and sternum were found to be larger in male and the difference was statistically significant. Among the various indices studied, none showed statistically significant difference between male and female. The combined length of manubrium and sternum was found to be the most accurate for determination of sex among all studied parameters, which accurately indentified 24.56% of sterna as male and 11.53% as female by the method of demarking point. Conclusion: The combined length of sternum and manubrium is the most reliable criteria for the determination of the sex of a sternum. Various indices, defined in relation to manubrium and sternum, were found to be non effective for the determination of sex of a sternum

Determination of sex from the width and the area of human sternum & manubrium in Gujarat population

Background: Determination of sex from the skeletal remains is of immense importance in the field of forensic medicine, physical anthropometry and anthropology. Various previous studies have demonstrated sternum as an important tool for the determination of sex. Aims: Aim of the present study was to establish normal range of values for the width and the area of sternum in the studied population and evaluate the sexual dimorphism in the sternum. Material & Methods: The present study was conducted at M.P. Shah Govt. Medical College, Jamnagar on Computed tomography scans of a total of 83 adult Gujarati individuals (57 males, 26 females). The sternal width and the sternal area were measured and analysed. Results: The width of the sternum at 1st and 3rd sternebrae and sternal area were found to be larger in male and the difference was statistically significant. The sternal area was found to be the most accurate for determination of sex among all studied parameters, which accurately identified 59.63% of sterna as male and 30.77% as female by the method of identification point. Conclusion: The sternal area is the most reliable criteria for the determination of the sex of a sternum. The widths of the sternum were found to be non-accurate for the determination of sex of a sternum. The sternum of the female is on average narrower and smaller than the male sternum

The effect of temperature on adhesion forces between surfaces and model foods containing whey protein and sugar

The formation of fouling deposit from foods and food components is a severe problem in food processing and leads to frequent cleaning. The design of surfaces that resist fouling may decrease the need for cleaning and thus increase efficiency. Atomic force microscopy has been used to measure adhesion forces between stainless steel (SS) and fluoro-coated glass (FCG) microparticles and the model food deposits (i) whey protein (WPC), (ii) sweetened condensed milk, and (iii) caramel. Measurements were performed over a range of processing temperatures between 30 and 90 oC and at contact times up to 60 s. There is a significant increase in adhesion force of both types of microparticle to WPC at 90 oC for all contact times. For confectionary deposits adhesion to SS was similar. Adhesion of confectionary deposits to FCG at 30 oC revealed a decrease in adhesion compared to SS; at higher temperatures the adhesion forces were similar