On dissipation intermittency and its modelling in terms of turbulence-chemistry interactions

A key challenge in combustion research is to model complex turbulence-chemistry interactions during extinction and re-ignition of non-premixed ames. These are caused when the scalar dissipation, , is above (or below) certain limits such that the diffusive temperature ux from the ame is much larger (or smaller) than chemical heat-release. is characterised by its small-scale intermittency, i.e. large uctuations in are frequent and localised in space. This behaviour severely constrains its resolvability and has implications for modelling extinction/re-ignition processes. Scalar eld statistics from the direct numerical simulation (DNS) database of a spatially-evolving, turbulent jet ame with multi-step chemistry by Pantano (2004) are studied using three different approaches, namely analysis of dissipation-spectra, direct investigation of dissipation contours and spatial filtering of the instantaneous dissipation signals. Out of these the spatial filtering method is found to be most suited for capturing the intermittent dissipation length scales and an Reδ-1 scaling is proposed for 'adequate' -resolution in turbulent jet ame experiments/simulations. Furthermore, a Multiple Mapping Conditioning (MMC) approach with two reference variables is used to model extinction/re-ignition in inhomogeneous turbulent jet ames. A new sub-model for the convective velocity term is employed that does not need to presume Gaussian statistics and consistent closures for MMC drift and diffusion coefficients are derived. Effect of temperature uctuations on scalar diffusivity is also accounted for. Joint scalar PDFs, conditional dissipation and conditional species predictions from MMC, and also conditional species concentrations from conventional singly- and doubly-conditioned moment closure (CMC1 and CMC2), are assessed against the Pantano DNS database. CMC1 expectedly over-predicts extinction and does not capture re-ignition, whereas extinction and re-ignition effects on species concentrations (including atomic H-radical) are captured satisfactorily using CMC2 and MMC. However, MMC scores over CMC2 because models for the joint scalar PDF evolution and conditional dissipation are self-contained in the former

A reanalysis of a strong-flow gyrokinetic formalism

We reanalyse an arbitrary-wavelength gyrokinetic formalism [A. M. Dimits, Phys. Plasmas 17, 055901 (2010)], which orders only the vorticity to be small and allows strong, time-varying flows on medium and long wavelengths. We obtain a simpler gyrocentre Lagrangian up to second order. In addition, the gyrokinetic Poisson equation, derived either via variation of the system Lagrangian or explicit density calculation, is consistent with that of the weak-flow gyrokinetic formalism [T. S. Hahm, Phys. Fluids 31, 2670 (1988)] at all wavelengths in the weak flow limit. The reanalysed formalism has been numerically implemented as a particle-in-cell code. An iterative scheme is described which allows for numerical solution of this system of equations, given the implicit dependence of the Euler-Lagrange equations on the time derivative of the potential

The use of routine chemoprophylaxis for deep vein thrombosis in all patients undergoing hip and knee replacements in rural population - whether it is justified?

Background: Deep vein thrombosis (DVT)/ pulmonary embolism (PE) are one of the most feared complications in patients undergoing joint replacements in western literatures. The exact incidence of DVT in Indians particularly rural population remains debatable. Also ways to prevent it in rural population is a dilemma for the orthopedic community. Hence this study was undertaken.Methods: We carried a prospective study of 135 cases of joint replacements i.e. 78 of total hip replacements and 57 of total knee replacements. None of the patients were given any form of chemoprophylaxis like low molecular weight heparin (LMWH). Strict monitoring was done. All patients underwent duplex ultrasonographic doppler assessment of both the lower limbs between the 4th-7th day and on 14th - 16th postoperative day. Only 5 out of 135 cases had DVT. Results: We observed that DVT developed more commonly following total hip replacement surgery (4 cases) as compared to total knee replacement (1 case). There was no mortality in our study.Conclusions: DVT following total joint replacements in rural Indian patients is not as common as reported in the Western literature. A high level of suspicion and close clinical monitoring is mandatory. The use of routine chemoprophylaxis in every patient is perhaps not justified. In future further more trials with a larger number of patients and at multiple centers would be required to confirm the findings of our study and to formulate guidelines to prevent DVT

Arbitrary-wavelength, dynamic-strong-flow gyrokenetics

Gyrokinetics is a maximally optimal description of low-frequency magnetised plasma turbulence. We present a generalisation of gyrokinetic theory that allows dynamic strong flows and is valid for arbitrary-wavelength electrostatic potential perturbations in slab magnetic geometry. We obtain a substantially simpler gyrocentre Lagrangian than that of Dimits (2010a,b). We present a symplectic strong-flow generalisation of gyrokinetic field theory such that, unlike Dimits (2010a,b), our Vlasov-Poisson system is manifestly conservative as, ultimately, we obtain it as a whole, directly from our gyrocentre particle Lagrangian (Scott and Smirnov, 2010). Despite the symplectic representation of our strong-flow theory, our Poisson equation is consistent with that for weak flows (Hahm, 1988) at all wavelengths and the fluid equation obtained from our Vlasov-Poisson system is consistent with fluid theory. Again, despite our symplectic representation, we demonstrate numerical tractability by solving implicit dependences using an iterative scheme. Weak-and strong- flow code verification are performed in limits that admit analytic comparison. Simulations show strong-flow symmetry breaking of the Kelvin-Helmholtz in-stability of a shear layer and blobs that manifest as asymmetries in the growth rate and propagation, respectively, that depend on the sign of the parallel vorticit

Forced vital capacity, forced expiratory volume in 1st second and forced expiratory ratio in automobile spray paint workers

Background: Automobile industry is a place where workers are exposed to harmful chemicals and toxic substances. Workers engaged in automobile spray painting are at a risk of developing respiratory problems. This is due to exposure to low molecular weight compounds (isocyanates) in spray paints.Methods: The present study was conducted on 100 male subjects comprising of the study group (n=50) and the control group (n=50), 18-35 years of age, non-smoker and with no pre occupational respiratory illness. The study group included workers working for 6-8 hours a day and exposed to spray paints for ≤5 years and the controls were age and BSA matched healthy office workers of the same locality. A preformed questionnaire was given to subjects and pulmonary functions parameters (forced vital capacity (FVC), forced expiratory volume in 1st second (FEV1), forced expiratory ratio (FEV1/FVC)) were recorded by computerised spirometer (Medspiror).Results: The two groups did not differ significantly on physical parameters. The pulmonary function parameters of the study group (FVC p=0.036, FEV1/FVC p=0.000) were found to be significantly different when compared to that of controls. As the age, weight, height and BSA increases there was a significant decrease in FEV1 in study group. Duration of exposure (<3 and more than equal to 3) had no statistically significant impact on pulmonary function tests (FVC p=0.139, FEV1 p=0.339, FEV1/FVC p=0.158) in the study  group.Conclusions: Exposure to automobile spray paint impairs lung functions

Evaluation of vitamin-D status in premenopausal and postmenopausal type-2 diabetic women and its relation to glycemic control

Background: Vitamin D deficiency is a public health problem around the world. In 2008, it was estimated that 1 billion persons present with vitamin D insufficiency or deficiency. Vitamin D is obtained through exposure to ultraviolet B (UVB) sunlight as well as nutritional sources. Despite the high UVB sunlight exposure in tropical countries, studies suggest Vitamin D deficiency is highly prevalent. Vitamin D is believed to help improve the body’s sensitivity to insulin, the hormone responsible for regulating blood sugar levels, thus reducing the risk of insulin resistance, which is often a precursor to Type-2 diabetes. Aim and objective of the study was to evaluate and compare the Vitamin-D levels in Premenopausal and Postmenopausal Type-2 Diabetic women and to evaluate if their Vitamin-D levels have any co-relation with their glycemic control.Methods: The study was conducted in Government Medical College Jammu and its associated hospital on 60 Type-2 Diabetic women, 30 premenopausal and 30 postmenopausal. Vitamin-D [25(OH) Vitamin D] levels were assessed by Chemiluminescence method in the Biochemistry Lab. of Govt. Medical College Jammu. Blood sugar levels, both fasting and postprandial, were assessed by Glucose oxidase-peroxidase method in the same Lab.HbA1C was assessed by HPLC [High Performance Liquid Chromatography] assay.Results: Vitamin-D deficiency [Vitamin-D levels <20 ng/ml] was seen in 16.67% of premenopausal type-2 diabetics and in 36.67% postmenopausal type-2 diabetics. This was not related to the glycemic control as HbA1C was increased in both the groups.Conclusions: Vitamin-D deficiency is more prevalent in postmenopausal Type-2 diabetics, as compared to premenopausal type-2 diabetics

Relationship between intake of artificial sweeteners and body mass index in young non-diabetic adults: a cross-sectional study

Background: Artificial sweeteners have skyrocketed the market in the last decade and there are unlimited products available today that contain them. They are often projected as one of the easy and effortless method of cutting down calories and have gained importance in the community. They are being used as one of the dietary tools to control or prevent weight gain not only in diabetic adults but also in young healthy adults and children. There is a need to examine any possible contribution of these substances on body weight and BMI of an individual.Methods: A cross sectional study was conducted among randomly selected healthy non-diabetic subjects of both sexes in the age group 18-35 years. Those with history of intake of artificial sweeteners in the last one year (in the form of pellets or diet soda) were considered as study group and equal no of non-users were taken as comparison group for study purpose. A pretested semi structured questionnaire prepared in English language was used to collect information. Variables such as height, weight and body mass index were noted. Data was analyzed using SPSS (version 20.0).Results: There was a statistically significant difference between the two groups in terms of weight and BMI (p=0.003 and 0.002 respectively). The mean weight and BMI was more in those subjects who had consumed more than one serving of diet can per day. Sweeteners in pellet form failed to show any statistical significance association between frequency of use and BMI.Conclusions: The study suggested of a possible association between the use of artificial sweeteners and BMI. Young adults need to be sensitized about various safe weight management techniques and healthy lifestyle, rather than resorting to methods like intake of artificial sweeteners

Mental health of mothers with malnourished children in Nepal: a prospective observational study

© 2024 The Authors. Published by The Nepal Health Research Council. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.33314/jnhrc.v21i4.4965Background: Maternal mental health may influence the nutritional status of their children. It was intended to assess the mental health status of the mothers of children admitted to a nutrition rehabilitation center. We specifically explored the relationship between maternal mental health and malnutrition of the child; to observe any change of maternal depressive/anxiety symptoms and weight gain in the child following admission. Methods: In a prospective observational study, malnutrition of children was assessed based on weight for height z scores using the WHO Anthro-Survey-Analyser. We evaluated anxiety using the Generalized Anxiety Disorder Scale (GAD-7) and depression by Patient Health Questionnaire (PHQ-9). Demographic and clinical variables were collected. Results: The degree of malnutrition of the children at admission and discharge was: mild (3.6% v 31.7%), moderate (37.7% v 26.3%), severe (58.7% v 8.4%), and no malnutrition (0.0% v 33.5%) (p<0.001). At admission, 12% of mothers had anxiety, depression, or both, which decreased to 3.0% at the time of discharge. There was no difference in malnutrition scores among children of mothers with or without anxiety/depression at admission or discharge, except that children of depressed mothers continued to have significantly greater levels of malnutrition at discharge compared with the mothers without depression. Maternal anxiety or depression was not associated with the severity of malnutrition. Conclusions: A proportion of mothers of children with malnutrition had clinical anxiety and depression; and maternal mental health concerns, especially depression may influence the nutrition of children. It is imperative to explore maternal mental health routinely for malnourished children

Household Vulnerability to Flood Disasters among Tharu Community, Western Nepal

Monsoon floods are frequent in the Tarai region of Nepal and claim thousands of lives and substantial numbers of properties every year. Certain human activities are more affected than others in the case of the same hazard. This study analyzes vulnerability to flooding among Tharu households. Data were collected by employing household surveys, group discussions, and key informant interviews in the Thapapur Village Development Committee (VDC) of Kailali district, western Tarai, Nepal. The analysis presented in this study is based on the theory that underpins the pressure and release (PAR) and access models. The results show that Tharu people are the major inhabitants in the study area and they prefer to live within their community; many ex-bonded laborers (marginalized people) choose this location for residence. Human causalities have been reduced in recent years due to easy access to cell phones, which has facilitated effective flood warnings with suitable lead times, but agriculture production loss and other losses are still high. Agricultural land is not only an important natural asset but is also considered a financial asset due to its high price and private ownership. The study concludes that subsistence agriculture-based households with small landholding sizes and less income diversification are highly vulnerable to flooding. Improper resettlement of ex-bonded laborers and land fragmentation due to separation of family members are the most prominent factors resulting in small landholdings. The results can guide government authorities to develop proper flood management strategies for the people living in the lowlands (particularly the Tarai region) of Nepal.publishedVersio

Microalgae as next generation plant growth additives: Functions, applications, challenges and circular bioeconomy based solutions

Sustainable agriculture practices involve the application of environment-friendly plant growth promoters and additives that do not negatively impact the health of the ecosystem. Stringent regulatory frameworks restricting the use of synthetic agrochemicals and the increase in demand for organically grown crops have paved the way for the development of novel bio-based plant growth promoters. In this context, microalgae biomass and derived agrochemicals offer novel sources of plant growth promotors that enhance crop productivity and impart disease resistance. These beneficial effects could be attributed to the presence of wide range of biomolecules such as soluble amino acid (AA), micronutrients, polysaccharides, phytohormones and other signaling molecules in microalgae biomass. In addition, their phototrophic nature, high photosynthetic efficiency, and wide environmental adaptability make them an attractive source of biostimulants, biofertilizers and biopesticides. The present review aims to describe the various plant growth promoting metabolites produced by microalgae and their effects on plant growth and productivity. Further, the effects elicited by microalgae biostimulants with respect to different modes of applications such as seed treatments, foliar spray and soil/root drenching is reviewed in detail. In addition, the ability of microalgae metabolites to impart tolerance against various abiotic and biotic stressors along with the mechanism of action is discussed in this paper. Although the use of microalgae based biofertilizers and biostimulants is gaining popularity, the high nutrient and water requirements and energy intensive downstream processes makes microalgae based technology commercially unsustainable. Addressing this challenge, we propose a circular economy model of microalgae mediated bioremediation coupled with biorefinery approaches of generating high value metabolites along with biofertilizer applications. We discuss and review new trends in enhancing the sustainability of microalgae biomass production by co-cultivation of algae with hydroponics and utilization of agriculture effluents