Effect of density variation and non-covalent functionalization on the compressive behavior of carbon nanotube arrays

Arrays of aligned carbon nanotubes (CNTs) have been proposed for different applications, including electrochemical energy storage and shock-absorbing materials. Understanding their mechanical response, in relation to their structural characteristics, is important for tailoring the synthesis method to the different operational conditions of the material. In this paper, we grow vertically aligned CNT arrays using a thermal chemical vapor deposition system, and we study the effects of precursor flow on the structural and mechanical properties of the CNT arrays. We show that the CNT growth process is inhomogeneous along the direction of the precursor flow, resulting in varying bulk density at different points on the growth substrate. We also study the effects of non-covalent functionalization of the CNTs after growth, using surfactant and nanoparticles, to vary the effective bulk density and structural arrangement of the arrays. We find that the stiffness and peak stress of the materials increase approximately linearly with increasing bulk density.

Glatiramer acetate-specific antibody titres in patients with relapsing / remitting multiple sclerosis and in experimental autoimmune encephalomyelitis

Glatiramer acetate (GA) is an immunomodulatory drug approved for the treatment of clinically isolated syndrome (CIS) and relapsing/remitting multiple sclerosis (RRMS). As an antigen-based therapy, GA induces GA-specific antibodies in treated patients and animals. GA-specific antibodies do not neutralize therapeutic effects on relapses and disability. Rather, it has been suggested that GA-specific antibodies may be associated with improved clinical outcomes. We evaluated antibody responses in eight patients with RRMS treated with GA for 15 months and antibody responses in GA-treated C57BL/6 mice before and after induction of experimental autoimmune encephalomyelitis (EAE). There were no significant differences from pretreatment levels of total IgE or GA-specific IgE in patients with RRMS. Total IgG1, IgG3 and GA-specific IgG4 were significantly increased at 15 months of GA treatment. Antibody type and titre were not associated with clinical outcomes, i.e. expanded disability status scale (EDSS) score, disease burden on magnetic resonance images (MRI) or clinical relapses. In contrast, mice with EAE showed a marked increase in GA-specific IgE and GA-specific IgG1 antibody responses. GA-treated mice demonstrated improved clinical symptoms and lower mortality than untreated controls. Our results suggest that antibody responses to GA are heterogeneous among patients with RRMS, with no apparent association between antibody response and clinical outcomes. Clinical improvements in EAE-induced GA-treated mice suggest that GA-specific IgE and IgG1 may contribute to GA treatment effects in EAE.

Ternary phase diagram of model dentin adhesive exposed to over-wet environments

When adhesives and/or composites are bonded to the tooth, water in the environment can interfere with proper interface formation. Formation of water blisters and phase separation at the adhesive/dentin interface have appeared as new types of bond defects. To better understand this problem, we determined the near-equilibrium partition of the hydrophobic/hydrophilic components when exposed to over-wet environments. Model methacrylate-based adhesives were mixed with different amounts of water to yield well-separated aqueous and resin phases. It was found that less than 0.1% BisGMA but nearly one-third of the HEMA diffused into the aqueous phase, leaving the remaining resin phase relatively hydrophobic. A partial phase diagram was created for the ternary BisGMA/HEMA/water system. All the experimental phase partitioning data were plotted, and the points lay on a binodal curve that separated the single-phase region from the two-phase region. We obtained the 3 tie lines by connecting the 2 points of each conjugate pair of the phase partitioning data from the 3 sets of tripartite mixtures. Information about solubility, water miscibility, distribution ratio, and phase partitioning behavior could be obtained quantitatively. This type of phase diagram will provide a more thorough understanding of current adhesive performance and elucidate directions for further improvement.

High prevalence and low awareness, treatment and control of hypertension in Asian Indian women

Hypertension is an important public health problem in India. To determine its prevalence, awareness, treatment and control among women, we performed a nationwide study. Population-based studies among women aged 35-70 years were performed in four urban and five rural locations. Stratified sampling was performed and we enrolled 4608 (rural 2604 and urban 2004) of the targeted 8000 (57%). Demographic details, medical history, diet, physical activity, anthropometry and blood pressure (BP) were recorded. Descriptive statistics are reported. Logistic regression was performed to determine the association of hypertension and its awareness, treatment and control with socioeconomic factors. Age-adjusted prevalence of hypertension (known or BP≥140/≥90 mm Hg) was observed in 1672 women (39.2%) (rural 746, 31.5%; urban 926, 48.2%). Significant determinants of hypertension were urban location, greater literacy, high dietary fat, low fibre intake, obesity and truncal obesity (P<0.01). Hypertension awareness was noted in 727 women (42.8%), more in urban (529, 56.8%) than in rural (198, 24.6%). Of these, 38.6% of the women were on treatment (urban 35.7, rural 46.5) and of those treated, controlled blood pressure (<140 and <90 mm Hg) was observed in 21.5% (urban 28.3 vs 10.2). Among hypertensive subjects, treatment was noted in 18.3% (rural 13.1, urban 22.5) and control in 3.9% (rural 1.3, urban 5.9). A significant determinant of low awareness, treatment and control was rural location (multivariate-adjusted P<0.05). There is a high prevalence of hypertension in middle-aged Asian Indian women. Very low awareness, treatment and control status are observed.

Potential allergens of green gram (Vigna radiata L. Millsp) identified as members of cupin superfamily and seed albumin

BACKGROUND

No systematic study on allergenicity of green gram seed proteins have been performed so far, although incidences of IgE-mediated reaction to green gram seedlings have been reported.

OBJECTIVE

We sought to investigate the allergenic potential of green gram, followed by identification and characterization of its relevant allergens using proteomic approaches.

METHODS

BALB/c mice were sensitized intraperitoneally with green gram proteins, and levels of specific Igs, Th2 cytokines, histamine, anaphylactic symptoms and histopathological responses were studied. Twelve naso-bronchial allergic patients with a history of sensitization to green gram were selected on the basis of positive skin prick test and elevated specific IgE levels. Green gram allergens were identified and characterized by their ability to endure pepsin, by IgE immunoblot of two-dimensional (2D) gels in combination with mass spectrometry and by bioinformatics approaches.

RESULTS

Increased specific IgE, IgG1, Th2 cytokine and histamine levels, high anaphylactic scores and histological changes in lungs and spleen of green gram crude protein extract-treated mice are indicative of its sensitization ability. Four proteins (molecular weights: 52, 50, 30 and 18 kDa) showed pepsin resistance and IgE-binding capability with sensitized human and mice sera. The four proteins tentatively named as Vig r2 (52 kDa, pI 5.7), Vig r3 (50 kDa, pI 5.8), Vig r4 (30 kDa, pI 6.6) and Vig r5 (18 kDa, pI 5.5) showed significant sequence similarity with known allergens of soybean, lentil, pea, lupin, etc. Mass spectrometric analysis identified Vig r2 as 8S globulin β-isoform precursor, Vig r3 as 8S globulin α-isoform precursor and Vig r4 as seed albumin.

CONCLUSION AND CLINICAL RELEVANCE

Green gram seeds contain at least four clinically relevant allergenic proteins, namely Vig r2, Vig r3, Vig r4 and Vig r5 that were capable of inducing strong IgE-mediated reactions. One of the most important steps towards diagnostic and therapeutic approaches to deal effectively with food allergy is continued identification of newer food allergens and their characterization. The significance of this study can be enormous as the data generated may work as basic biology data in developing a green gram species modified genetically that may have reduced allergenicity.

A review of the epidemiology of diabetes in rural India

OBJECTIVE

To describe the extent of problem of diabetes in rural India based on review of available literature and examine the secular trends over a period of 15 years i.e. from 1994 to 2009.

METHODS

A systematic search was performed using electronic as well as manual methods. Studies providing details of sample size, age group of participants, criteria used for diagnosis, along with the prevalence of any of the three outcomes of interest i.e. diabetes mellitus, impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), were included.

RESULTS

Analysis of secular trends reveals an increase in diabetes prevalence among rural population at a rate of 2.02 per 1000 population per year. The rate of increase was high in males (3.33 per 1000 per year) as compared to females (0.88 per 1000 per year). High prevalence of IFG and IGT has been observed in southern and northern parts of the country.

CONCLUSION

The prevalence of diabetes is rising in rural India. There is a large pool of subjects with IFG and IGT at high risk of conversion to overt diabetes. Population-level and individual-level measures are needed to combat this increasing burden of diabetes.

Dislocation Models for Strengthening in Nanostructured Metallic Multilayers

Ultra-high strength metallic multilayers are ideal for investigating the effects of length scales in plastic deformation of metallic materials. Experiments on model systems show that the strengths of these materials increase with decreasing bilayer period following the Hall-Petch model. However, as the layer thickness is reduced to the nm-scale, the number of dislocations in the pile-up approaches one and the pile-up based Hall-Petch model ceases to apply. For nm-scale semi-coherent multilayers, we hypothesize that plastic flow occurs by the motion of single dislocation loops, initially in the softer layer, that deposit misfit type dislocation arrays at the interface and transfer load to the harder phase. The stress concentration eventually leads to slip in the harder phase, overcoming the resistance from the misfit arrays at the interface. A model is developed within the framework of classical dislocation theory to estimate the strengthening from this mechanism. The model predictions are compared with experimentally measured strengths.

Resistance training for obese, type 2 diabetic adults: a review of the evidence

In both developed and developing countries, increased prevalence of obesity has been strongly associated with increased incidence of type 2 diabetes mellitus (T2DM) in the adult population. Previous research has emphasized the importance of physical activity in the prevention and management of obesity and T2DM, and generic exercise guidelines originally developed for the wider population have been adapted for these specific populations. However, the guidelines traditionally focus on aerobic training without due consideration to other exercise modalities. Recent reviews on resistance training in the T2DM population have not compared this modality with others including aerobic training, or considered the implications of resistance training for individuals suffering from both obesity and T2DM. In short, the optimal mix of exercise modalities in the prescription of exercise has not been identified for it benefits to the metabolic, body composition and muscular health markers common in obesity and T2DM. Similarly, the underlying physical, social and psychological barriers to adopting and maintaining exercise, with the potential to undermine the efficacy of exercise interventions, have not been addressed in earlier reviews. Because it is well established that aerobic exercise has profound effects on obesity and T2DM risk, the purpose of this review was to address the importance of resistance training to obese adults with T2DM.

Obesity-related non-communicable diseases: South Asians vs White Caucasians

South Asians are at higher risk than White Caucasians for the development of obesity and obesity-related non-communicable diseases (OR-NCDs), including insulin resistance, the metabolic syndrome, type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD). Rapid nutrition and lifestyle transitions have contributed to acceleration of OR-NCDs in South Asians. Differences in determinants and associated factors for OR-NCDs between South Asians and White Caucasians include body phenotype (high body fat, high truncal, subcutaneous and intra-abdominal fat, and low muscle mass), biochemical parameters (hyperinsulinemia, hyperglycemia, dyslipidemia, hyperleptinemia, low levels of adiponectin and high levels of C-reactive protein), procoagulant state and endothelial dysfunction. Higher prevalence, earlier onset and increased complications of T2DM and CHD are often seen at lower levels of body mass index (BMI) and waist circumference (WC) in South Asians than White Caucasians. In view of these data, lower cut-offs for obesity and abdominal obesity have been advocated for Asian Indians (BMI; overweight >23 to 24.9 kg m(-2) and obesity ≥ 25 kg m(-2); and WC; men ≥ 90 cm and women ≥ 80 cm, respectively). Imbalanced nutrition, physical inactivity, perinatal adverse events and genetic differences are also important contributory factors. Other differences between South Asians and White Caucasians include lower disease awareness and health-seeking behavior, delayed diagnosis due to atypical presentation and language barriers, and religious and sociocultural factors. All these factors result in poorer prevention, less aggressive therapy, poorer response to medical and surgical interventions, and higher morbidity and mortality in the former. Finally, differences in response to pharmacological agents may exist between South Asians and White Caucasians, although these have been inadequately studied. In view of these data, prevention and management strategies should be more aggressive for South Asians for more positive health outcomes. Finally, lower cut-offs of obesity and abdominal obesity for South Asians are expected to help physicians in better and more effective prevention of OR-NCDs.

Dissimilation of Carbon Monoxide to Acetic Acid by Glucose-Limited Cultures of Clostridium thermoaceticum

Clostridium thermoaceticum was cultivated in glucose-limited media, and the dissimilation of CO to acetic acid was evaluated. We found that cultures catalyzed the rapid dissimilation of CO to acetic acid and CO(2), with the stoichiometry obtained for conversion approximating that predicted from the following reaction: 4CO + 2H(2)O --> CH(3)CO(2)H + 2CO(2). Growing cultures formed approximately 50 mmol (3 g) of CO-derived acetic acid per liter of culture, with the rate of maximal consumption approximating 9.1 mmol of CO consumed/h per liter of culture. In contrast, resting cells were found not to dissimilate CO to acetic acid. CO was incorporated, with equal distribution between the carboxyl and methyl carbons of acetic acid when the initial cultivation gas phase was 100% CO, whereas CO(2) preferentially entered the carboxyl carbon when the initial gas phase was 100% CO(2). Significantly, in the presence of saturating levels of CO, CO(2) preferentially entered the methyl carbon, whereas saturating levels of CO(2) yielded CO-derived labeling predominantly in the carboxyl carbon. These findings are discussed in relation to the path of carbon flow to acetic acid.

Trends in yield and effects of screening intervals during 17 years of a large UK community-based diabetic retinopathy screening programme

AIMS

To describe changes in risk profiles and yield in a screening programme and to investigate relationships between retinopathy prevalence, screening interval and risk factors.

METHODS

We analysed a population of predominantly Type 2 diabetic patients, managed in general practice, and screened between 1990 and 2006, with up to 17 years' follow-up and up to 14 screening episodes each. We investigated associations between referable or sight-threatening diabetic retinopathy (STDR), screening interval and frequency of repeated screening, whilst adjusting for age, duration and treatment of diabetes, hypertension treatment and period.

RESULTS

Of 63 622 screening episodes among 20 788 people, 16 094 (25%) identified any retinopathy, 3136 (4.9%) identified referable retinopathy and 384 (0.60%) identified STDR. The prevalence of screening-detected STDR decreased by 91%, from 1.7% in 1991-1993 to 0.16% in 2006. The prevalence of referable retinopathy increased from 2.0% in 1991-1993 to 6.7% in 1998-2001, then decreased to 4.7% in 2006. Compared with screening intervals of 12-18 months, screening intervals of 19-24 months were not associated with increased risk of referable retinopathy [adjusted odds ratio 0.93, 94% confidence interval (CI) 0.82-1.05], but screening intervals of more than 24 months were associated with increased risk (odds ratio 1.56, 95% CI 1.41-1.75). Screening intervals of < 12 months were associated with high risks of referable retinopathy and STDR.

CONCLUSIONS

Over time the risk of late diagnosis of STDR decreased, possibly attributable to earlier diagnosis of less severe retinopathy, decreasing risk factors and systematic screening. Screening intervals of up to 24 months should be considered for lower risk patients.

Development of a virtual reality training curriculum for laparoscopic cholecystectomy

Background

Training within a proficiency-based virtual reality (VR) curriculum may reduce errors during real surgical procedures. This study used a scientific methodology for development of a VR training curriculum for laparoscopic cholecystectomy.

Methods

Inexperienced (had performed fewer than ten laparoscopic cholecystectomies), intermediate (20–50) and experienced (more than 100) surgeons were recruited. Construct validity was defined as the ability to differentiate between the three levels of experience, based on simulator-derived metrics for nine basic skills, four procedural tasks and full laparoscopic cholecystectomy on a high-fidelity VR simulator. Inexperienced subjects performed ten repetitions for learning curve analysis. Proficiency measures were based on the performance of experienced surgeons.

Results

Thirty inexperienced, 11 intermediate and 16 experienced operators were recruited. Eight of nine basic skills and three of four procedural tasks were found to be construct valid. The full procedure revealed significant intergroup differences for time (1541, 673 and 816 s; P = 0·002), movements (1021, 595 and 638; P = 0·006) and path length (2038, 1235 and 1303 cm; P = 0·033). Learning curves plateaued between the second and ninth sessions.

Conclusion

This study shows that it is possible to define and develop a whole-procedure VR training curriculum for laparoscopic cholecystectomy using structured scientific methodology.

Peritoneal closure or non-closure at caesarean section

At caesarean section, the closure or non-closure of the parietal and/or the visceral peritoneum has short-term and long-term advantages and disadvantages. The majority of reports have compared double closure vs double non-closure, non-closure of the parietal, or non-closure of the visceral parietal, with special emphasis on operation time, febrile morbidity, and duration of hospital stay. The present study compares the three methods in 692 consecutive caesarean sections in a South African rural hospital, with special emphasis on wound sepsis, operation time and febrile morbidity. The prevalence of wound sepsis and febrile morbidity was 4.9% and 2.5%, respectively. The only significant difference between the three groups was that double closure resulted in the longest operation time.

Acute unilateral cataract in a postpartum adolescent with poorly-controlled type 1 diabetes

Acute cataract is recognized as a rare complication in adolescents with type 1 diabetes mellitus and may be associated with rapid improvement in glycaemia in patients with newly diagnosed diabetes. Transient cataracts, which resolve following improved metabolic control, and irreversible cataracts requiring surgery have also previously been documented. Development or progression of retinopathy may complicate pregnancy in women with diabetes. To our knowledge, we present the first case report of an acute cataract developing postpartum in a woman with type 1 diabetes. This rare case serves to demonstrate a possible association between acute cataract and altered glycaemic control in pregnancy. Acute cataract should be considered in any woman with diabetes who develops sudden visual loss following pregnancy.

A case-control study on insulin resistance, metabolic co-variates & prediction score in non-alcoholic fatty liver disease

BACKGROUND & OBJECTIVE

Asian Indians have a high prevalence of insulin resistance and the metabolic syndrome. Currently, non-alcoholic fatty liver disease (NAFLD) is considered to be an integral part of the metabolic syndrome with insulin resistance as a central pathogenic factor. We studied anthropometric parameters, insulin resistance and metabolic co-variates in subjects with NAFLD as compared to those without NAFLD, and also developed a prediction score for NAFLD.

METHODS

Thirty nine subjects with NAFLD and 82 controls were selected for the study after ultrasonography of 121 consecutive apparently healthy subjects. Anthropometric profile [body mass index (BMI), waist circumference (WC) etc,], lipid profile, hepatic aminotransferases, fasting blood glucose (FBG), insulin were recorded and value of homeostasis model assessment of insulin resistance (HOMA-IR) was analysed. Step-wise logistic regression analysis and area under the receiver operator curve (aROC) were analysed to arrive at a prediction score.

RESULTS

Overall, prevalence of NAFLD was 32.2 per cent and prevalence of metabolic syndrome was seen in 41 per cent among cases and 19.5 per cent in controls (P<0.01). Subjects with NAFLD had significantly higher values of BMI, WC, hip circumference, FBG, fasting insulin, total cholesterol and serum triglycerides. Step-wise logistic regression analysis showed odds ratio (OR) and 95 per cent confidence interval (CI) for BMI [ 4.3 (1.6, 11.3)], FBG [5.5 (1.5, 19.8)] and fasting insulin [ 2.4 (1.0, 5.8)] as independent predictors of NAFLD. The prediction score for NAFLD was; 1 (fasting insulin) +1.6 (BMI) + 1.9 (FBG) (sensitivity of 84.6%, specificity of 51.2% and aROC 76%).

INTERPRETATION & CONCLUSION

In this study, presence of NAFLD indicated close relationship with multiple features of metabolic syndrome. The prediction score developed could be used as a screening tool to predict NAFLD among Asian Indians in north India.

Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management

Asian Indians exhibit unique features of obesity; excess body fat, abdominal adiposity, increased subcutaneous and intra-abdominal fat, and deposition of fat in ectopic sites (liver, muscle, etc.). Obesity is a major driver for the widely prevalent metabolic syndrome and type 2 diabetes mellitus (T2DM) in Asian Indians in India and those residing in other countries. Based on percentage body fat and morbidity data, limits of normal BMI are narrower and lower in Asian Indians than in white Caucasians. In this consensus statement, we present revised guidelines for diagnosis of obesity, abdominal obesity, the metabolic syndrome, physical activity, and drug therapy and bariatric surgery for obesity in Asian Indians after consultations with experts from various regions of India belonging to the following medical disciplines; internal medicine, metabolic diseases, endocrinology, nutrition, cardiology, exercise physiology, sports medicine and bariatric surgery, and representing reputed medical institutions, hospitals, government funded research institutions, and policy making bodies. It is estimated that by application of these guidelines, additional 10-15% of Indian population would be labeled as overweight/obese and would require appropriate management. Application of these guidelines on countrywide basis is also likely to have a deceleration effect on the escalating problem of T2DM and cardiovascular disease. These guidelines could be revised in future as appropriate, after another large and countrywide consensus process. Till that time, these should be used by clinicians, researchers and policymakers dealing with obesity and related diseases.

Consensus statement for diagnosis of obesity, abdominal obesity and the metabolic syndrome for Asian Indians and recommendations for physical activity, medical and surgical management

Asian Indians exhibit unique features of obesity; excess body fat, abdominal adiposity, increased subcutaneous and intra-abdominal fat, and deposition of fat in ectopic sites (liver, muscle, etc.). Obesity is a major driver for the widely prevalent metabolic syndrome and type 2 diabetes mellitus (T2DM) in Asian Indians in India and those residing in other countries. Based on percentage body fat and morbidity data, limits of normal BMI are narrower and lower in Asian Indians than in white Caucasians. In this consensus statement, we present revised guidelines for diagnosis of obesity, abdominal obesity, the metabolic syndrome, physical activity, and drug therapy and bariatric surgery for obesity in Asian Indians after consultations with experts from various regions of India belonging to the following medical disciplines; internal medicine, metabolic diseases, endocrinology, nutrition, cardiology, exercise physiology, sports medicine and bariatric surgery, and representing reputed medical institutions, hospitals, government funded research institutions, and policy making bodies. It is estimated that by application of these guidelines, additional 10-15% of Indian population would be labeled as overweight/obese and would require appropriate management. Application of these guidelines on countrywide basis is also likely to have a deceleration effect on the escalating problem of T2DM and cardiovascular disease. These guidelines could be revised in future as appropriate, after another large and countrywide consensus process. Till that time, these should be used by clinicians, researchers and policymakers dealing with obesity and related diseases.