A Mathematical Model Of Blood Flow Of A Stenosed Artery In Variable Shape

In this theoretical study, a mathematical model is developed to carry out a systematic analysis of flow behaviour in a two-dimensional vessel (modeled as artery) with a locally variable shaped constriction. An artificial artery, which containing a viscous incompressible fluid that representing the flowing blood can be treated as inflexible vessel. The shape of the stenosis in the arterial lumen is chosen to be symmetric as well as asymmetric about the middle cross section is perpendicular to the axis of the vessel. The constricted vessel is resolved into a straight vessel and the entire resulting equations are solved by a numerical method with Reynolds number and ‘n’, a number giving the shape of the constriction as parameters. The impacts of these parameters on wall shear stress, pressure gradient and velocity have been analysed. It is found that the flow resistance decreases as the shape of a smooth stenosis changes and extreme resistance is attained for the symmetric stenosis. But the length of separation increases for the asymmetric constrictions and the oscillation in the shear layer appears earlier for asymmetric constriction than that in the case of symmetric constriction. The extreme resistance is attained for inflexible stenosed vessel rather than the flexible one

Nutritional status of under-five children in rural Bangladesh

A cross-sectional study was carried out in Dumki Upazila of Patuakhali district in Bangladesh to assess the prevalence of stunting, wasting and underweight among the under-five children. Anthropometric measurements were taken from all children, aged 0-59 months in the studied area using wooden height board and digital weight machine. We used WHO Anthro software for analyzing the z scores of the children. A total of 4409 (2296 boys and 2113 girls) under five children were counted for anthropometric analysis.  Regarding the Height-for-age Z-score (HAZ), the study revealed that the prevalence of stunting was 27.10% (95% CI: 25.8-28.5) of the children while 7.80% (95% CI: 7-8.6) were severe stunting. By assessing the Weight-for-height Z-score (WHZ), the study showed that 11.20% (95% CI: 10.3-12.1) were wasting whereas 3% (95% CI 2.5-3.5) were severe wasting. According to Weight-for-age Z-score (WAZ), about 18.20% (95% CI: 17-19.3) were underweight and 4.1% (95% CI: 3.5-4.7) were underweight. The findings of the study show that prevalence of stunting is very high. Focusing on childhood stunting is a high priority, and there should be comprehensive efforts to increase the overall nutritional status of the under-five children in this area

Studies on Dispersion of Insoluble Sulfur in Passenger Car Radial Belt Skim Compound

Good dispersion of compounding ingredients in a rubber formulation is crucial for mechanical performance. After mixing, certain materials like sulfur, recycled materials, and zinc oxide can remain undispersed within the rubber matrix, which can lead to critical flaws and influence performance. Improper dispersion is one of the reasons for poor physico mechanical properties. The influence of temperature, mixing time and storage time of different grades of insoluble sulfur collected from one source are studied along with the standard sample of different sources. To better understand the reason for poor sulfur dispersion and high blooming, all the chemical and physical properties are analysed. The topological structures are evaluated using the thermomechanical techniques. The reason for poor dispersion and premature failure of the rubber specimen has been studied by SEM-EDS. The degradation of insoluble sulfur to soluble sulfur can be negligible during the melt mixing if the mixing is done in a controlled way. The final mixing temperature shall be maintained at 90 °C to 95 °C to restrict the insoluble to soluble sulfur conversion. This paper highlights the methodology of the development of oil-coated sulfur in rubber composites and provides insight into the dispersion of polymeric sulfur in natural rubber-based tyre carcass compounds

Computer vision syndrome, musculoskeletal, and stress-related problems among visual display terminal users in Nepal

Background The use of computers and other Visual Display Terminal (VDT) screens is increasing in Nepal. However, there is a paucity of evidence on the prevalence of Computer Vision Syndrome (CVS) and other occupational health concerns among employees working in front of VDT screens in the Nepalese population. Objectives This study aims to estimate the prevalence of CVS, musculoskeletal and work-related stress among VDT screen users in the office, as well as their understanding and usage of preventive measures. Methods The study was a cross-sectional descriptive study among 319 VDT users in office settings in Kathmandu Metropolitan City, Nepal, using a semi-structured self-administered questionnaire. Multivariate logistic regression analysis was conducted to identify the associated factors at 95% CI. P-value Results The prevalence of CVS was 89.4%. More than eight out of ten study participants reported at least one visual and musculoskeletal symptom. Work-related stress, which was moderate-difficult to handle, was present in 36.7% of the study population. The mean±SD computer usage per day was 7.9±1.9 hours. Tired eye (63.3%), feeling of dry eye (57.8%), headache (56.9%) were the common visual symptoms of CVS reported. Total computer use/day > = 8 hours OR 2.6, improper viewing distance OR 3.2, Not using an anti-glare screen OR 2.6, not using eye-drops, and not wearing protective goggles OR 3.1 were significantly associated with the presence of CVS. There was no statistically significant association between visual symptoms of CVS, musculoskeletal symptoms, and stress with gender. Conclusion CVS was substantially related to not employing preventive measures, working longer hours, and having an incorrect viewing distance. With more hours per day spent in front of a VDT screen, work-related stress and musculoskeletal complaints were also found to be important correlates. Similarly, work-related stress was found more among those who had less than five years of job

Structural Adaptation of Ni₄O₄ Units To Form Cubane, Open Dicubane, Dimeric Cubane, and One-Dimensional Polymeric Cubanes: Magnetostructural Correlation of Ni₄ Clusters

The complexation reactions of a tripodal chelating ligand, [3,5-bis­(2-amino-ethyl)-[1,3,5]­triazinan-1-yl]-methanol (<b>L</b>), which is produced by the <i>in situ</i> transformation of 1,3,6,8-tetraazatricyclo­[4.4.1.1^3,8]­dodecane (<b>L</b>^<b>1</b>) with Ni­(NO₃)₂·6H₂O has been explored in the presence of ammonium salts of inorganic and organic anions. These reactions resulted in four crystalline complexes [Ni₄(<b>L</b>)₂­(μ₃-OH)₂­(NCS)₄]·4H₂O (<b>1</b>), [Ni₄(<b>L</b>)₂­(μ₂-N₃)₄­(N₃)₂]·2H₂O (<b>2</b>), [Ni₈(<b>L</b>)₄­(μ₃-OH)₄­(BDC)₃­(H₂O)₄]·BDC·28­(H₂O) (<b>3</b>, BDC = 1,4-benzene dicarboxylate) and {[Ni₄(<b>L</b>)₂­(μ₃-OH)₂­(NDS)₂­(H₂O)₂]·NDS·11­(H₂O)}_<i>n</i> (<b>4</b>, NDS = naphthalene-1,5-disulfonate). The crystal structure analyses of <b>1</b>–<b>4</b> reveal that all contain Ni­(II) clusters, which act as secondary building units to generate higher order aggregates. The complexes <b>1</b>, <b>3</b>, and <b>4</b> contain exclusively Ni₄ cubane units: a discrete cubane in <b>1</b>, a dimer of cubanes linked by BDC in <b>3</b>, and cubanes linked in one dimension by NDS to form a 1D-coordination polymer in <b>4</b>. Interestingly, complex <b>2</b> exhibits an open dicubane with two missing vertices. Although a plethora of water molecules had been included in their crystal lattices, the crystals were found to be stable even at room temperature. The water molecules govern the overall crystal packing by the formation of strong hydrogen bonds and clusters. Large clusters of water such as (H₂O)₂₈ and (H₂O)₁₆ were observed in <b>3</b> and <b>4</b>, respectively, while dimers of water were observed in <b>1</b> and <b>2</b>. Magnetic susceptibility (χ_M) measurements in the temperature range of 2–300 K on <b>1</b>–<b>3</b> reveal that the metal centers are ferromagnetically coupled in all three depending on their respective exchange pathways. Interestingly, the room temperature (300 K) χ_M<i>T</i> values increase as the molecular aggregation increases from discrete cubane (5.5 cm³ K mol^–1) to face sharing open dicubane (6.21 cm³ K mol^–1) to connected dicubane (11.36 cm³ K mol^–1). The modes of bridging by ^–OH, N₃^–, and BDC and their bond angles with paramagnetic Ni­(II) centers clearly explained the overall ferromagnetism operating in the spin clusters

Aryl aryl methyl thio arenes prevent multidrug-resistant malaria in mouse by promoting oxidative stress in parasites

We have synthesized a new series of aryl aryl methyl thio arenes (AAMTAs) and evaluated antimalarial activity in vitro and in vivo against drug-resistant malaria. These compounds interact with free heme, inhibit hemozoin formation, and prevent Plasmodium falciparum growth in vitro in a concentration-dependent manner. These compounds concentration dependently promote oxidative stress in Plasmodium falciparum as evident from the generation of intraparasitic oxidants, protein carbonyls, and lipid peroxidation products. Furthermore, AAMTAs deplete intraparasite GSH levels, which is essential for antioxidant defense and survival during intraerythrocytic stages. These compounds displayed potent antimalarial activity not only in vitro but also in vivo against multidrug-resistant Plasmodium yoelii dose dependently in a mouse model. The mixtures of enantiomers of AAMTAs containing 3-pyridyl rings were found to be more efficient in providing antimalarial activity. Efforts have been made to synthesize achiral AAMTAs 17–23 and among them, compound 18 showed significant antimalarial activity in viv

Cd(II) complexation with 1,1-dithiolate and nitrogen donors: synthesis, luminescence, crystal structure, and antifungal activity study

<div><p>A new luminescent complex of Cd(II) with 1,1-dicyanoethylene-2,2-dithiolate [i-MNT²⁻ = {S₂C : C(CN)₂}²⁻] with 1,3-diaminopropane (tn) and 4-methyl pyridine (γ-picoline) as secondary ligands has been synthesized and characterized on the basis of spectroscopy and single-crystal X-ray diffraction analysis. Single-crystal X-ray diffraction analysis reveals that cadmium(II) is five coordinate in a 1-D polymer. Biological screening effects <i>in vitro</i> of the synthesized complex has been tested against five fungi <i>Synchytrium endobioticum</i>, <i>Pyricularia oryzae</i>, <i>Helminthosporium oryzae</i>, <i>Candida albicans</i> (ATCC10231), and <i>Trichophyton mentagrophytes</i> by the disk diffusion method. A comparative study of inhibition zone values of K₂i-MNT·H₂O and {[Cd(tn)(iMNT)(4-MePy)]·4H₂O}_n (<b>1</b>) indicates that the complex exhibits antifungal activity, whereas K₂i-MNT·H₂O became silent on <i>S. endobioticum</i>, <i>P. oryzae</i>, <i>H. oryzae</i>, <i>C. albicans (ATCC10231),</i> and <i>T. mentagrophytes</i>.</p></div