Controlled Degradation of Methacrylonitrile Polymers and Copolymers

This research is concerned with the preparation, characterisation and thermal degradation of methacrylonitrile based polymers and copolymers. Various methacrylonitrile homopolymers including those containing reactive chain ends and methacrylonitrile copolymers with other comonomers (e.g. methacrylic acid, styrene and maleic anhydride) were prepared, characterised and their thermal behaviour was also studied under programmed and isothermal heating experiments using TVA, TG and DTA techniques. Polymer degradation is a complex branch of chemistry. A general description of the major types of degradation processes which may occur during thermal decomposition is given in Chapter One. This chapter also includes a brief review of the significance of polymer structure in polymer degradation. Chapter Two details the experimental procedure of the several thermal analysis techniques employed in the present work, with special emphasis on thermal volatilisation analysis as a more versatile technique. A brief description of additional analytical methods used in identifying and quantifying degradation products is also included. Chapter Three describes the preparation, isolation and characterisation of various homo- and copolymers of methacrylonitrile used in the present investigation. This also includes a brief description of the calculation determination of monomer feed for the preparation of copolymers of any required composition. The experimental work regarding the thermal aspects of various methacrylonitrile polymers and copolymers is described in Chapters Four, Five, Six, Seven and Eight. Chapter Four is concerned, as a basis, with the thermal behaviour of high and low molecular weight methacrylonitrile polymers made using AIBN and benzoyl peroxide as initiators. It is observed that polymer simply depolymerises to monomer (as it is expected from a polymer with l:l-disubstituted structure) in a two stage decomposition. The first stage of decomposition is attributed to the depolymerisation initiated from unsaturated chain ends and the second (and main stage in high molecular weight polymers) to unzipping after random chain scission. This chapter also contains a literature review on the thermal degradation of polymethacrylonitrile The programmed thermal degradation of methacrylonitrile polymers and copolymers capable of colouration is detailed in Chapters Five and Six, respectively. The thermal degradation of methacrylonitrile polymers with reactive chain-ends is the subject of Chapter Five. Programmed heating experiments were employed to investigate the effect of colouration initiated from the polymer chain ends on the thermal degradation of polymethacrylonitrile, and on the products of degradadon. It has been observed, in these studies, that the end-initiated methacrylonitrile polymer samples did not simply depolymerise to monomer as has been expected1 and observed2 in case of a polymer made from 1:1 disubstituted monomer. Monomer yields were significantly decreased with increasing reactive chain ends. A large amount of residue, cold ring fraction, volatile liquid products (mainly monomer) and various gases (condensable and non-condensable) were found amongst the degradation products. Oligomers with various naphthyridine types of structure were suggested to be present in CRF. Formation of these other degradation products indicateded towards some degradative routes other than depolymerisation. The thermal degradation of methacrylonitrile copolymers containing small amounts of methacrylic acid is considered in Chapter Six in order to asses, the effect of thermal colouration initiated from inside the polymer chain on thermal behaviour and products of degradation. It has been observed that with increasing concentration of MAA units in the copolymer chain, there is an increase in the relative amounts of residue and cold ring fraction (formed as a result of nitrile group cyclisation4) together with a corresponding decrease in the monomer yield. The degradation products from MAN/MAA copolymers were almost the same as has been identified in case of end-initiated methacrylonitrile polymers. A mechanism for the degradation products from MAN polymers with reactive chain ends and MAN/MAA copolymers has been put forward. In Chapter Seven, the thermal stability and degradation behaviour of a set of methacrylonitrile/styrene copolymers is discussed. It was found that the thermal behaviour of these copolymer samples can be related to that of polymethacrylonitrile and polystyrene. It was concluded that the mechanism of decomposition below and above 30

Solid Waste for Knit Fabric: Quantification and Ratio Analysis

The study analyses the solid waste in the knit apparel industry of Bangladesh and the exploitation of waste generated from different categories of input fabrics. It also explores the waste producing rate for the accumulated waste on daily or shift basis in the several sections in the knit apparel industry of Bangladesh, and the environmental collision for this. Nevertheless numerous issues are allied to the knit apparel industry of Bangladesh in terms of the congregated wastes, the study briefly analyses those issues with a prominence on management attempt. This study intends to provide an extensive study that covers the types of solid waste in the knit apparel industry, the differences of waste according to the several sections and the kind of industry. Thus the major research question that as explored is: “what are the solid waste substances and the producing rate inside the knit apparel industries?” Data collected from the knit industries by the intensive observations and following a semi structured open ended questionnaire. All the sources (primary and secondary) are justified and utilized with the progression of this study. Key words: Knit, Apparel, Fabric, Solid Waste, Compliance, Composite and Jhoot

EFFECT OF TERMINALIA CHEBULA (HARAD) FRUIT EXTRACT ON CARDIOTOXICITY IN STREPTOZOTOCIN INDUCED DIABETIC RATS

Objective: The aim of the study was to explore the protective activity of Terminalia chebula fruit extract on cardiotoxicity in streptozotocin (STZ) induced diabetic rats.Methods: The animals were divided into eight groups of five each and were fed with high fat diet (HFD) except sham control, diabetic control and isoproterenol control. Diabetes was induced by administering single intraperitoneal (i. p.) injection of STZ (0.05 g/kg) in all groups except sham and isoproterenol control and was confirmed by testing blood glucose level after 48 h. Rats were pretreated with ethanolic extract of Terminalia chebula (0.25& 0.5 g/kg/d; per oral (p. o.)), pioglitazone (0.01 g/kg/d), carvedilol (0.002 g/kg/d) and normal saline throughout the study period (14 days). Cardiotoxicity was induced by the administrating two subcutaneous (s. c) injection of isoproterenol (ISO) (0.085 g/kg) at an interval of 24 h. Troponin was checked to confirm cardiotoxicity. The evaluation parameters include initial and final blood glucose level, change in body weight, food efficiency ratio (FER), heart weight-body weight ratio, biochemical estimations and histopathological studies.Results: Pretreatment with Terminalia chebula produced significant (p<0.01) decrease in blood glucose level and heart weight-body weight ratio. It significantly decrease the elevated activity of the cardiac marker enzymes, alanine transaminase (ALT), lactate dehydrogenase (LDH), creatinine kinase (CK-MB) (p<0.01), similar to the standard drug carvedilol in isoproterenol injected rats. Pretreatment with Terminalia chebula showed absence of troponin and lesser degree of necrosis, edema, and myofibrillar degeneration.Conclusion: Terminalia chebula has significant cardioprotective action against cardiotoxicity in STZ induced diabetic rats, which is comparable with standard drugs i.e., pioglitazone and carvedilol.Â

A COMPREHENSIVE STUDY ON LITERATURE EVIDENCE, CLINICAL STUDIES AND PRACTICES OF HERBAL DRUGS FOR DIABETIC NEUROPATHY AND CARDIOMYOPATHY

  Diabetes mellitus is a worldwide epidemic disease that eventually advances to a chronic stage and affects different vital organs by intensifying the underlying pathological factors, and through the remodeling of the tissues by the generation of reactive oxygen species leading to the development of respective organ failure. Two such complications are painful neuropathy and cardiomyopathy; both of which are common and progressive complications of diabetes. The symptoms of peripheral neuropathy include tingling, burning, lancinating pain, hyperesthesia, and allodynia. The course of the disease progression may vary from intermittent, mild symptoms to severe chronic, and daily pain; which culminates into poor quality of life. Another complication of diabetes mellitus, diabetic cardiomyopathy, is defined as a ventricular dysfunction disorder that occurs in diabetic patients. The development of the disease is characterized by a hidden subclinical period, during which cellular, structural changes and abnormalities lead to diastolic dysfunction, followed by systolic dysfunction, and terminating into heart failure. Left ventricular hypertrophy, metabolic abnormalities, extracellular matrix changes, small vessel disease, cardiac autonomic neuropathy, insulin resistance, oxidative stress, and apoptosis are the most important pathological advancements that lead to diabetic cardiomyopathy. Various pharmaceutical agents from different pharmacological categories have been proposed for the symptomatic treatment of painful diabetic neuropathy; however, it is a herculean task to select a drug due to the wide range of choices and lack of consistent guidelines for treatment. Similarly, treatment of cardiomyopathy is based on the general therapeutic rules of management of heart failure and no specifications have yet been addressed for this condition. Therefore, more studies are required to improve our knowledge of these complex syndromes. From this perspective, this review is designed to delineate a general overview of neuropathy and cardiomyopathy, referring to the conventional therapies in use and possible unconventional, natural, herbal, and safe treatments for both the above-mentioned complications of diabetes

A Clinical Insight into Gestational Diabetes

Pregnancy is a diabetogenic state manifested by insulin resistance and hyperglycaemia. The age group at risk of getting gestational diabetes is between 20 and 39 years in 96.8% of cases. Gestational diabetes is the development of symptoms and signs of diabetes mellitus during pregnancy and the glucose level reverting to normal during puerperium. Depending on the type of population and the diagnostic criteria used, gestational diabetes is said to complicate 1–16% of all pregnancies. Many researchers in American, European and Asian surveys have reported 3–6% of prevalence. Compared with white European women, the prevalence rate for GD is increased approximately elevenfold in women from the Indian subcontinent, eightfold in South East Asia, sixfold and threefold in Arab and black Afro-Caribbean women, respectively. Such figures draw a potent clinical interest towards gestational diabetes (GD), and this chapter attempts to highlight some major aspects of GD in respect to both the mother and the foetus or the newborn specially emphasizing on its management as per the World Health Organization (WHO) and International Federation of Gynaecology and Obstetrics (FIGO)

EFFECT OF ETHANOLIC EXTRACT OF GLYCYRIZZA GLABRA AGAINST STEREPTOZOTOCIN AND HIGH FAT DIET INDUCED DIABETES AND HYPERLIPIDEMIA

Objective: To study the effect of ethanolic extract of Glycyrrhiza glabra against streptozotocin and high-fat-diet-induced diabetes and hyperlipidemia.Methods: The present study was conducted on a 14 d model in which Glycyrrhiza glabra extract was given to Streptozotocin (STZ; 50 mg/kg; i. p.) induced diabetic rats fed with high fat diet (HFD), and its protective effect has been studied. The antihyperlipidemic and antihyperglycemic effects have been evaluated on the basis of physical, biochemical as well as histomorphological parameters.Results: The Glycyrrhiza glabra extract pre-treated group showed a significant decrease in biochemical parameters like Total cholesterol (TC), Triglyceride (TG), High-density lipoprotein (HDL), Lactate dehydrogenase(LDH), Alanine transaminase (ALT) compared with D-HFD group (p<0.01). The pre-treated groups also showed significant protection in physical parameters as compared to D-HFD group (p<0.01) which was also confirmed by histopathological studies. All these results were compared and found to be similar with two standard drugs metformin (500 mg/kg) and atorvastatin (10 mg/Kg).Conclusion: This study concluded that alcoholic extract of Glycyrrhiza glabra (500 mg/kg) has significant antidiabetic and antihyperlipidemic potential against streptozotocin and high-fat diet induced diabetic hyperlipidemic rats comparable to the clinically used drugs.Keywords: Atherosclerosis, Diabetic hyperlipidemia, Diabetes mellitus, Hyperlipidemia, Lipid profile, Streptozotoci

A conglomeration of preclinical models related to myocardial infarction

Cardiovascular diseases are the main source of death and morbidity in developed and developing nations. Animal models are required to propel our understanding of the pathogenesis, increase our knowledge, disease progress, and mechanism behind cardiovascular disorder, providing new approaches focused to improve the diagnostic and the treatment of these pathological conditions and additionally to test various therapeutic ways to deal with tissue regeneration and re-establish heart working following damage. A perfect model framework ought to be reasonable, effectively controlled, reproducible, and physiologically illustrative of human disease, show cardinal signs and pathology that resembles after the human ailment and ethically stable. The decision of selection of animal model should be considered precisely since it influences exploratory results and whether results of the research can be sensibly matched with the human. In this way, no specific technique splendidly reproduces the human disease, and relying upon the model, extra cost burden, resources, infrastructure and the necessity for technical hands, should also be kept under consideration. Here we have discussed and compiled various methods of inducing myocardial infarction in animals, basically by surgery, chemicals and through genetic modification, this may benefit the researchers in getting a complied data regarding various methods through which they can induce myocardial infarction in animals

Bromelain capped gold nanoparticles as the novel drug delivery carriers to aggrandize effect of the antibiotic levofloxacin

To develop bromelain capped gold nanoparticles (BRN capped Au-NPs) as the effective drug delivery carriers of the antibiotic levofloxacin (LvN) and evaluate antibacterial potential of its bioconjugated form compared to pure LvN. BRN capped Au-NPs were synthesized by in vitro method and bioconjugated to LvN using 1-ethyl-3-(3-dimethylamino-propyl)-carbodiimide as activator to form Au-BRN-LvN-NPs. These were characterized for mean particle size by dynamic light scattering analysis, zeta potential by Zetasizer nanosystem analysis and transmission electron microscopy (TEM) on carbon coated TEM copper grids by TEM respectively. Drug loading efficiency of LvN was calculated using UV-visible spectroscopy by standard curve of pure LvN. Antibacterial efficacy of Au-BRN-LvN-NPs and pure LvN was determined by evaluating minimum inhibitory concentration (MIC) against Staphylococcus aureus and Eschereschia coli.Two peaks were observed in Au-BRN-LvNNPs spectrum one at 307 nm and other at 526 nm while one peak in BRN capped Au-NPs at 522 nm during UV spectroscopy suggesting red shift. The drug loading efficiency of LvN was found to be 84.8 ± 2.41 %. The diameter of Au-BRN-LvN-NPs and BRN capped Au-NPs were found to be (58.65 ± 2 nm, 38.11 ± 2 nm), zeta potential (-9.01 mV, -13.8 mV) and surface morphology (~13.2 nm, 11.4 nm) respectively. The MICs against S. aureus and E. coli were found to be (0.128 μg/mL, 1.10 μg/mL) for Au-BRN-LvN-NPs and (0.547 μg/mL, 1.96μg/mL) for pure LvN. The results suggested that BRN capped Au-NPs can be used as effective drug delivery carriers of the antibiotic LvN. The Au-BRN-LvN-NPs exhibited enhanced antibacterial activity compared to pure LvN alone

Monitoring impacts of WASH interventions: the case of SHEWA-B

UNICEF and its government counterpart are implementing a large WASH programme with explicit behavioural change goals. A baseline survey showed that handwashing with soap (HWWS) was most frequent after defecation (17%) or cleaning a child’s anus (23%), and lowest around foodrelated events (<1%). Observed practices are sharply poorer than selfreported behavior. After one year, significant improvement was noted in handwashing practices following contact with faecal matter, but HWWS before preparation, serving or eating of food remained stubbornly low. Open defecation had declined, most notably in the poorest quintile. Morbidity was not significantly different in control and intervention households. However, intervention households were significantly more likely to have coliformfree household water (48%) than were control households (32%). This robust monitoring framework has allowed the project to understand WASH practices in the target communities in detail, and to identify areas of success and areas where efforts need to be redoubled

Global burden and strength of evidence for 88 risk factors in 204 countries and 811 subnational locations, 1990–2021: a systematic analysis for the Global Burden of Disease Study 2021

Background: Understanding the health consequences associated with exposure to risk factors is necessary to inform public health policy and practice. To systematically quantify the contributions of risk factor exposures to specific health outcomes, the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 aims to provide comprehensive estimates of exposure levels, relative health risks, and attributable burden of disease for 88 risk factors in 204 countries and territories and 811 subnational locations, from 1990 to 2021. Methods: The GBD 2021 risk factor analysis used data from 54 561 total distinct sources to produce epidemiological estimates for 88 risk factors and their associated health outcomes for a total of 631 risk–outcome pairs. Pairs were included on the basis of data-driven determination of a risk–outcome association. Age-sex-location-year-specific estimates were generated at global, regional, and national levels. Our approach followed the comparative risk assessment framework predicated on a causal web of hierarchically organised, potentially combinative, modifiable risks. Relative risks (RRs) of a given outcome occurring as a function of risk factor exposure were estimated separately for each risk–outcome pair, and summary exposure values (SEVs), representing risk-weighted exposure prevalence, and theoretical minimum risk exposure levels (TMRELs) were estimated for each risk factor. These estimates were used to calculate the population attributable fraction (PAF; ie, the proportional change in health risk that would occur if exposure to a risk factor were reduced to the TMREL). The product of PAFs and disease burden associated with a given outcome, measured in disability-adjusted life-years (DALYs), yielded measures of attributable burden (ie, the proportion of total disease burden attributable to a particular risk factor or combination of risk factors). Adjustments for mediation were applied to account for relationships involving risk factors that act indirectly on outcomes via intermediate risks. Attributable burden estimates were stratified by Socio-demographic Index (SDI) quintile and presented as counts, age-standardised rates, and rankings. To complement estimates of RR and attributable burden, newly developed burden of proof risk function (BPRF) methods were applied to yield supplementary, conservative interpretations of risk–outcome associations based on the consistency of underlying evidence, accounting for unexplained heterogeneity between input data from different studies. Estimates reported represent the mean value across 500 draws from the estimate's distribution, with 95% uncertainty intervals (UIs) calculated as the 2·5th and 97·5th percentile values across the draws. Findings: Among the specific risk factors analysed for this study, particulate matter air pollution was the leading contributor to the global disease burden in 2021, contributing 8·0% (95% UI 6·7–9·4) of total DALYs, followed by high systolic blood pressure (SBP; 7·8% [6·4–9·2]), smoking (5·7% [4·7–6·8]), low birthweight and short gestation (5·6% [4·8–6·3]), and high fasting plasma glucose (FPG; 5·4% [4·8–6·0]). For younger demographics (ie, those aged 0–4 years and 5–14 years), risks such as low birthweight and short gestation and unsafe water, sanitation, and handwashing (WaSH) were among the leading risk factors, while for older age groups, metabolic risks such as high SBP, high body-mass index (BMI), high FPG, and high LDL cholesterol had a greater impact. From 2000 to 2021, there was an observable shift in global health challenges, marked by a decline in the number of all-age DALYs broadly attributable to behavioural risks (decrease of 20·7% [13·9–27·7]) and environmental and occupational risks (decrease of 22·0% [15·5–28·8]), coupled with a 49·4% (42·3–56·9) increase in DALYs attributable to metabolic risks, all reflecting ageing populations and changing lifestyles on a global scale. Age-standardised global DALY rates attributable to high BMI and high FPG rose considerably (15·7% [9·9–21·7] for high BMI and 7·9% [3·3–12·9] for high FPG) over this period, with exposure to these risks increasing annually at rates of 1·8% (1·6–1·9) for high BMI and 1·3% (1·1–1·5) for high FPG. By contrast, the global risk-attributable burden and exposure to many other risk factors declined, notably for risks such as child growth failure and unsafe water source, with age-standardised attributable DALYs decreasing by 71·5% (64·4–78·8) for child growth failure and 66·3% (60·2–72·0) for unsafe water source. We separated risk factors into three groups according to trajectory over time: those with a decreasing attributable burden, due largely to declining risk exposure (eg, diet high in trans-fat and household air pollution) but also to proportionally smaller child and youth populations (eg, child and maternal malnutrition); those for which the burden increased moderately in spite of declining risk exposure, due largely to population ageing (eg, smoking); and those for which the burden increased considerably due to both increasing risk exposure and population ageing (eg, ambient particulate matter air pollution, high BMI, high FPG, and high SBP). Interpretation: Substantial progress has been made in reducing the global disease burden attributable to a range of risk factors, particularly those related to maternal and child health, WaSH, and household air pollution. Maintaining efforts to minimise the impact of these risk factors, especially in low SDI locations, is necessary to sustain progress. Successes in moderating the smoking-related burden by reducing risk exposure highlight the need to advance policies that reduce exposure to other leading risk factors such as ambient particulate matter air pollution and high SBP. Troubling increases in high FPG, high BMI, and other risk factors related to obesity and metabolic syndrome indicate an urgent need to identify and implement interventions