Mathematical model of pulsatile flow of non-Newtonian fluid in tubes of varying cross-sections and its implications to blood flow

The effects of rheological behavior of blood and pulsatility on flow through an artery with stenosis have been investigated. Blood has been represented by a non-Newtonian fluid obeying Herschel–Bulkley equation. Using the Reynolds number as the perturbation parameter, a perturbation technique is adopted to solve the resulting quasi-steady non-linear coupled implicit system of differential equations. Analytical expressions for velocity distribution, wall shear stress, volumetric flow rate and the mean flow resistance have been obtained. It is observed that the wall shear stress and flow resistance increase for increasing value of yield stress with other parameters held fixed. One of the remarkable results of the present analysis is not only to bring out the effect of the size of the stenosis but also to study the influence of the shape of the stenosis. The change in the shape of the stenosis brings out a significant change in the value of flow resistance but it has no effect on the variation of wall shear stress except shifting the point (where it attains its maximum value) towards downstream. It is pertinent to point out that pulsatile flow of Newtonian fluid, Bingham plastic fluid and Power-law fluid become particular cases of the present model. The present approach has general validity in comparison with many mathematical models developed by others and may be applied to any mathematical model by taking into account of any type of rheological property of blood. The obtained velocity profiles have been compared with the experimental data and it is observed that blood behaves like a Herschel–Bulkley fluid rather than Power-law and Bingham fluids. Finally, some biorheological applications of the present model have briefly been discussed.     

Peer relations and the understanding of faux pas: longitudinal evidence for bidirectional associations

Research connecting children's understanding of mental states to their peer relations at school remains scarce. Previous work by the authors demonstrated that children's understanding of mental states in the context of a faux pas--a social blunder involving unintentional insult--is associated with concurrent peer rejection. The present report describes a longitudinal follow-up investigation of 210 children from the original sample, aged 5-6 or 8-9 years at Time 1. The results support a bidirectional model suggesting that peer rejection may impair the acquisition of faux pas understanding, and also that, among older children, difficulties in understanding faux pas predict increased peer rejection. These findings highlight the important and complex associations between social understanding and peer relations during childhood.     

Correlation of Microalbuminuria with Estimated GFR (eGFR) by Cockcroft–Gault and MDRD Formula in Type 2 Diabetics and Hypertensives

Increase in urine albumin excretion rate (AER) precede a fall in glomerular filtration rate in patients developing diabetic chronic kidney disease (CKD). Our results have shown that 7 (50 %) of diabetic and hypertensive individuals with decreased GFR do not have increased AER. In this cross-sectional study, we measured AER of 75 patients with type 2 diabetes and hypertension by immunoturbidimetric method. We correlated the results with eGFR values obtained by Cockcroft–Gault and MDRD method. The method used was not a compensated method. We measured serum creatinine by modified Jaffe’s kinetic method in autoanalyzer XL-600. Analysis of data showed positive correlation between eGFR and microalbuminuria by both the methods with eGFR <60 mL/min/1.73 m². Pearson’s correlation co-efficient (r) was 0.9 (p = 0.0001) by Cockcroft–Gault formula and 0.69 (p = 0.0063) by MDRD formula. Our results concluded that there was positive correlation between AER and eGFR <60 mL/min/1.73 m². We have recognized that these two parameters provide a complimentary benefit in management of cases with CKD.     

Assay of tubercular antibody, circulating free and immune complexed antigen in the diagnosis of pulmonary tuberculosis

Analysis of tubercular antibody, circulating free and immune complexed antigen (CIC-Ag) was done in confimed pulmonary tuberculosis sera by ELISA, using ES-31 antigen and affinity purified anti ES-31 antibody. Twenty three of 25 (92%) tuberculosis sera were positive for IgG antibody to ES-31 antigen. Using anti ES-31 antibody, free tubercular antigen could be detected in 20 of 25 (80%) cases whereas circulating immune complexed antigen (CIC-Ag) in 18 of 25 (72%) cases by sandwich ELISA. Of the two sera showing absence of antibody, one showed presence of free and CIC-Ag whereas the other showed the presence of free antigen. Thus antigen assay may be used as an adjunct tool for confirmation of pulmonary tuberculosis.     

Maria Goeppert Mayer

This is a brief biography of Maria Goeppert Mayer. We have tried to emphasise that even outstanding women like her had to suffer (and still suffer) great discrimination. In spite of the handicaps she achieved the highest scientific distinction. B Banerjee, after his retirement from Tata Institute of Fundamental Research, has been teaching in the Physics Department, University of Mumbai. He is mainly interested in the application of nuclear physics to astrophysics and cosmology.     

Lipid peroxidation and spectrin of RBC membrane in hydroxyurea treated Eβ thalassaemia

The aim of the present work is to understand the effect of low dose of hydroxyurea (HU) therapy on oxidative damage of RBC membrane in non-transfused Eβ thalassaemia. HU was administered at a dose of 30 mg/kg/day for 90 consecutive days. The percentage of spectrin and the level of malondialdehyde (MDA), fetal hemoglobin (HbF), hemoglobin (Hb) and packed cell volume (PCV) were measured. The HbF level was significantly increased after 90 days of HU therapy. MDA level of RBC membrane was decreased. There was no change in PCV, Hb and spectrin content of RBC membrane after HU therapy for 90 days in Eβ thalassaemia. Increment of HbF in HU treated Eβ patient may have some role on the correction of oxidative damage of RBC membrane by inhibiting further degradation of spectrin and by decreasing lipid peroxidation of red cell membrane.     

Factors that explain placement decisions for students with multiple disabilities: findings from national data

The Special Education Elementary Longitudinal Study data set was utilised to examine the potential influences on placement decisions for students with multiple disabilities in the US. The sample consisted of 415 students. Specifically, the study investigated whether factors including students’ prior special education experiences, parental involvement, parental expectations and educational risk factors explain the placement of students in classrooms. Results indicate significant relations between the explanatory variables and the hours spent daily in general education classrooms. However, only two variables, parents’ education and receipt of early childhood special education services, were significantly associated with the dichotomised outcome of whether or not a child received any academic instruction in a general education classroom. Research limitations and implications for future research, policy and practice in the international context are discussed.     

Misconceptions Regarding Accommodations on High‐Stakes Tests: Recommendations for Preparing Disability Documentation for Test Takers with Learning Disabilities

The process of submitting documentation to testing agencies as proof of a disability can be time consuming, expensive, and even intimidating to test takers with learning disabilities. Misconceptions about the accommodations review process employed by testing agencies add to the anxiety that many test takers feel around obtaining approval for high‐stakes test accommodations. The objective of this article is to clarify some of these misconceptions as well as shed more light on the accommodation decision‐making process employed by testing agencies.