Geometric Mixing, Peristalsis, and the Geometric Phase of the Stomach

Mixing fluid in a container at low Reynolds number - in an inertialess environment - is not a trivial task. Reciprocating motions merely lead to cycles of mixing and unmixing, so continuous rotation, as used in many technological applications, would appear to be necessary. However, there is another solution: movement of the walls in a cyclical fashion to introduce a geometric phase. We show using journal-bearing flow as a model that such geometric mixing is a general tool for using deformable boundaries that return to the same position to mix fluid at low Reynolds number. We then simulate a biological example: we show that mixing in the stomach functions because of the "belly phase": peristaltic movement of the walls in a cyclical fashion introduces a geometric phase that avoids unmixing.Comment: Revised, published versio

AFe2As2 (A = Ca, Sr, Ba, Eu) and SrFe_(2-x)TM_(x)As2 (TM = Mn, Co, Ni): crystal structure, charge doping, magnetism and superconductivity

The electronic structure and physical properties of the pnictide compound families $RE$OFeAs ($RE$ = La, Ce, Pr, Nd, Sm), $A$Fe$_{2}$As$_{2}$ ($A$ = Ca, Sr, Ba, Eu), LiFeAs and FeSe are quite similar. Here, we focus on the members of the $A$Fe$_{2}$As$_{2}$ family whose sample composition, quality and single crystal growth are better controllable compared to the other systems. Using first principles band structure calculations we focus on understanding the relationship between the crystal structure, charge doping and magnetism in $A$Fe$_{2}$As$_{2}$ systems. We will elaborate on the tetragonal to orthorhombic structural distortion along with the associated magnetic order and anisotropy, influence of doping on the $A$ site as well as on the Fe site, and the changes in the electronic structure as a function of pressure. Experimentally, we investigate the substitution of Fe in SrFe$_{2-x}TM_{x}$As$_{2}$ by other 3$d$ transition metals, $TM$ = Mn, Co, Ni. In contrast to a partial substitution of Fe by Co or Ni (electron doping) a corresponding Mn partial substitution does not lead to the supression of the antiferromagnetic order or the appearance of superconductivity. Most calculated properties agree well with the measured properties, but several of them are sensitive to the As $z$ position. For a microscopic understanding of the electronic structure of this new family of superconductors this structural feature related to the Fe-As interplay is crucial, but its correct ab initio treatment still remains an open question.Comment: 27 pages, single colum

Drying kinetics and determination of water sorption isotherms of corn

The study was carried out for the purpose of determining the drying kinetics as well as moisture sorption isotherm of hybrid-81 corn. Corn at about 31% moisture content (wb) was dried in a forced convective hot air cabinet dryer at different drying conditions, such as variable air dry bulb temperature (40°C, 50°C and 60°C) and loading density (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2) as well as in shining sun at different layers (3.56 kg/m2, 7.12 kg/m2, and 10.68 kg/m2). The water sorption isotherm of the dried corn was developed using vacuum desiccators, which contained saturated salt solutions in the range of 11-93% RHs. The mono-layer moisture content calculated by the Brunauer–Emmett–Teller (BET) model (6.76 g/100 g solid) was lesser than that calculated by the Guggenheim–Anderson–De Boer (GAB) model (10.53 g/100 g solid). The energy constants were 10.45 and 4.64 as per BET and GAB equation, respectively. Both models gave suitable fits for corn. The activation energy (Ea) for diffusion of water was found to be 11.09 kcal/gm-mole for corn. Furthermore, it was noticed that, with the increase of corn layer, the drying rate decreased in case of both sun and mechanical drying. However, higher loading density resulted in efficient drying, at least up to 10.7 kg/m2. It was shown that the drying time to obtain stability was the lowest for moisture content (12.08 %) corresponding to aw of 0.65 in case of BET or GAB monolayer moisture content. This finding could be helpful in predicting the storage life of corn

Numerical study of nonlinear heat transfer from a wavy surface to a high permeability medium with pseudo-spectral and smoothed particle methods

Motivated by petro-chemical geological systems, we consider the natural convection boundary layer flow from a vertical isothermal wavy surface adjacent to a saturated non-Darcian high permeability porous medium. High permeability is considered to represent geologically sparsely packed porous media. Both Darcian drag and Forchheimer inertial drag terms are included in the velocity boundary layer equation. A high permeability medium is considered. We employ a sinusoidal relation for the wavy surface. Using a set of transformations, the momentum and heat conservation equations are converted from an (x, y) coordinate system to an (x,η) dimensionless system. The two-point boundary value problem is then solved numerically with a pseudo-spectral method based on combining the Bellman–Kalaba quasi linearization method with the Chebyschev spectral collocation technique (SQLM). The SQLM computations are demonstrated to achieve excellent correlation with smoothed particle hydrodynamic (SPH) Lagrangian solutions. We study the effect of Darcy number (Da), Forchheimer number (Fs), amplitude wavelength (A) and Prandtl number (Pr) on the velocity and temperature distributions in the regime. Local Nusselt number is also computed for selected cases. The study finds important applications in petroleum engineering and also energy systems exploiting porous media and undulating (wavy) surface geometry. The SQLM algorithm is shown to be exceptionally robust and achieves fast convergence and excellent accuracy in nonlinear heat transfer simulations

Proteases of haematophagous arthropod vectors are involved in blood-feeding, yolk formation and immunity : a review

Ticks, triatomines, mosquitoes and sand flies comprise a large number of haematophagous arthropods considered vectors of human infectious diseases. While consuming blood to obtain the nutrients necessary to carry on life functions, these insects can transmit pathogenic microorganisms to the vertebrate host. Among the molecules related to the blood-feeding habit, proteases play an essential role. In this review, we provide a panorama of proteases from arthropod vectors involved in haematophagy, in digestion, in egg development and in immunity. As these molecules act in central biological processes, proteases from haematophagous vectors of infectious diseases may influence vector competence to transmit pathogens to their prey, and thus could be valuable targets for vectorial control

Osmotic dehydration kinetics of oyster mushroom

This research was carried out to study the effect of osmotic dehydration behavior of oyster mushroom. The effect of solution concentration, immersion time and temperature on mass transfer parameters were observed during osmotic dehydration of oyster mushroom at three different temperatures −12, 27 and 45°C. A number of process parameters on osmotic dehydration such as water loss (WL), solid gain (SG), and normalized solid content (NSC) were investigated. Results showed that increase in salt concentration and immersion time resulted in %WL, %SG and NSC. The highest NSC (4.09 g solids/100g of initial weight of sample) was achieved for product osmosed in 25% salt solution for 6 hr immersion time. The pseudo diffusion coefficient, k was determined by using Fick’s First Law of diffusion equation. Plotting k values against inverse absolute temperature an Arrhenius type relationship was developed from which the calculated activation energy values of 1.8 and 3.64 kcal/gm-mole were obtained for 20% and 15% salt solution respectively

Integral waterproof concrete: A comprehensive review

The ingress of water and aggressive substances is the primary reason for the chemical and physical degradation of concrete infrastructure, leading to a reduction in durability and a shortening of life span. In practice, different integral waterproofing admixtures and surface coatings have been widely used to prevent or mitigate this problem. Compared with surface protection, the incorporation of integral waterproofing admixtures (such as densifiers, water repellents, and crystalline admixtures) in concrete has several benefits, such as ease of application, elimination of regular maintenance, and little or no deterioration over time. So far, there is no comprehensive review on integral waterproofing admixtures and their effects on various properties of concrete. This review examines existing literature on integral waterproof concrete containing various commercial and laboratory-made waterproofing admixtures. This comprehensive review highlights that the use of integral waterproofing admixtures has the potential to increase the service life and improve the durability of concrete structures and infrastructure. However, the admixtures may have a negative impact on some concrete properties, such as workability and strength. Whilst many hydrophobic and crystalline admixtures can reduce the water absorption rate of concrete by up to 80%, they often have a negative impact on the concrete compressive strength, causing a strength reduction of about 10% or more. Their influence on some durability properties (e.g., reinforcement corrosion, microbial-induced concrete corrosion) is inconclusive, indicating the need for further research. There is also a need to develop proper guidelines to determine the efficacy of integral waterproofing admixtures. More research is also required to assess the long-term performance of integral waterproof concrete and its benefits based on life cycle assessment

Multi-omics integration identifies NK cell-mediated cytotoxicity as a therapeutic target in systemic lupus erythematosus

BackgroundSystemic lupus erythematosus (SLE) is an autoimmune condition that impacts various organs. Given the intricate clinical progression of SLE, it is imperative to explore novel avenues for precise diagnosis and treatment.MethodsPeripheral blood mononuclear cells (PBMC) were isolated from 6 SLE patients before and after treatment, 7 healthy controls and 7 disease controls. Assay for Transposase Accessible Chromatin with high throughput Sequencing (ATAC-seq) was used to analyze the chromatin accessibility signatures and RNA-seq was used to identify the differentially expressed genes, mRNA, lncRNA, circRNA, miRNA. Then ATAC-seq and RNA-seq were integrated to further analyze hub genes and pathways. Finally, we validated gene expression levels and examined changes in key genes after treatment through in vitro experiments.ResultsOur analysis reveals dynamic changes in chromatin accessibility during the course of disease progression in SLE. Significantly higher numbers of differentially accessible regions, transcripts, genes, mRNA, lncRNA, circRNA, and miRNA were observed in SLE patients compared to other cohorts, with these variances markedly reduced post-treatment. Two gene clusters associated with SLE disease improvement were identified, with a total of 140 genes intersecting with ATAC results. Pathway analysis revealed that NK cell mediated cytotoxicity was the most differentiated and therapeutically altered pathway in SLE patients. Independent sample validation confirmed that the gene expression of this pathway was reduced in SLE patients and associated with disease activity, whereas hydroxychloroquine (HCQ) effectively elevated their expression in vitro.ConclusionOur findings suggest that these NK cell signature genes may be associated with the complex pathogenesis of SLE. The restoration of NK cell-mediated cytotoxicity may serve as a useful marker of improvement following SLE treatment

The burden of diseases and risk factors in Bangladesh, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background: Bangladesh has made substantial progress in improving socioeconomic and health indicators over the past 50 years, but data on national disease burden are scarce. We used data from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to estimate the burden of diseases and risk factors in Bangladesh from 1990 to 2019. / Methods: For this systematic analysis, we analysed data from vital registration systems, surveys, and censuses using multistage modelling processes to estimate life expectancy at birth, mortality rate, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs). Additionally, we compared the health status of Bangladesh with that of the other countries in the GBD south Asia region—Bhutan, India, Nepal, and Pakistan. / Findings: Life expectancy at birth in Bangladesh increased from 58·2 years (95% uncertainty interval 57·1–59·2) in 1990 to 74·6 years (72·4–76·7) in 2019. Between 1990 and 2019, the age-standardised mortality rate decreased from 1509·3 (1428·6–1592·1) to 714·4 (604·9–838·2) deaths per 100 000 population. In 2019, non-communicable diseases represented 14 of the top 20 causes of death; the leading three causes were stroke, ischaemic heart disease, and chronic obstructive pulmonary disease. High blood pressure, high fasting plasma glucose, and smoking were the top three risk factors. From 1990 to 2019, the rate of all-cause DALYs decreased by 54·9% (48·8–60·4). In 2019, the leading causes of DALYs and YLLs were neonatal disorders, stroke, and ischaemic heart disease, whereas musculoskeletal disorders, depressive disorders, and low back pain were the leading causes of YLDs. Bangladesh has the lowest age-standardised rates of mortality, YLDs, and YLLs and the highest life expectancy at birth in south Asia. / Interpretation: Over the past 30 years, mortality rates have reduced by more than half in Bangladesh. Bangladesh must now address the double burden of communicable and non-communicable diseases. Cost-effective, multisectoral efforts are needed to prevent and control non-communicable diseases, promote healthy lifestyles, and prevent premature mortality and disabilities. / Funding: Bill & Melinda Gates Foundation. / Translation: For the Bangla translation of the abstract see Supplementary Materials section