Spectrophotometric determination of nitrate in vegetables using phenol

A rapid and sensitive spectrophotometric method for the determination of nitrate in vegetables is described. The method is based on the measurement of the absorbance of yellow sodium nitrophenoxide formed via the reaction of phenol with the vegetable-based nitrate in presence of sulphuric acid. The analytical concentration of the acid has marked effect on the nitrate determined. The colour development was rapid and remained stable overnight. Analysis of six vegetable samples containing nitrate gave satisfactory mean recoveries of 76 to 123% in 18 determinations. The proposed method is reproducible and sensitive to lower level concentrations. Journal of Applied Sciences and Environmental Management Vol. 10(1) 2006: 79-8

Effective Free Energy for Individual Dynamics

Physics and economics are two disciplines that share the common challenge of linking microscopic and macroscopic behaviors. However, while physics is based on collective dynamics, economics is based on individual choices. This conceptual difference is one of the main obstacles one has to overcome in order to characterize analytically economic models. In this paper, we build both on statistical mechanics and the game theory notion of Potential Function to introduce a rigorous generalization of the physicist's free energy, which includes individual dynamics. Our approach paves the way to analytical treatments of a wide range of socio-economic models and might bring new insights into them. As first examples, we derive solutions for a congestion model and a residential segregation model.Comment: 8 pages, 2 figures, presented at the ECCS'10 conferenc

Trapping neutral fermions with kink-like potentials

The intrinsically relativistic problem of neutral fermions subject to kink--like potentials ($\sim \mathrm{tanh} \gamma x$) is investigated and the exact bound-state solutions are found. Apart from the lonely hump solutions for $E=\pm mc^{2}$, the problem is mapped into the exactly solvable Surm-Liouville problem with a modified P\"{o}schl-Teller potential. An apparent paradox concerning the uncertainty principle is solved by resorting to the concepts of effective mass and effective Compton wavelength.Comment: 13 page

Short courses of daily prednisolone during upper respiratory tract infections reduce relapse frequency in childhood nephrotic syndrome

Background Relapses of childhood nephrotic syndrome (NS) are frequently precipitated by viral upper respiratory tract infections (URTIs). A review of the literature reveals that in patients with steroid-dependent NS on alternate day corticosteroids, a short course of daily corticosteroid therapy during the course of an URTI may reduce relapse frequency. Objective To assess the effect of a short course of low-dose corticosteroid therapy during the course of an URTI on relapse frequency in patients with steroid-sensitive NS who have not been taking any treatment for a minimum period of 3 months. Methods A double-blind placebo-controlled crossover trial was conducted on 48 patients with idiopathic NS who had not been receiving corticosteroid therapy for a minimum of 3 months. Patients were randomized into two groups. Group A received 5 days of daily prednisolone at 0.5 mg/kg at the onset of an URTI while group B received 5 days of placebo. Both groups were followed up for 1 year and the URTI-induced relapse frequency was noted. A crossover was performed during the next year, with group A receiving placebo and group B receiving prednisolone. Results Thirty-three patients completed the study. In the treatment group, 115 episodes of URTI led to 11 relapses while in the control group 101 episodes of URTI led to 25 relapses. There was no significant difference between the mean number of URTIs between the treatment and control groups. The treatment group had significantly less relapses compared to the control group (p = 0.014). Within the treatment group, 65.6% did not relapse, while the remainder had a single relapse. In contrast, only 40.6% of the control group remained in remission while 40.6% suffered a single relapse and 18.8% had two or more relapses. Conclusions Prescribing a short course of daily corticosteroids during an URTI significantly reduces the frequency of URTI-induced relapse in patients with steroid-responsive NS who are off corticosteroid therapy

Nonlinear collective nuclear motion

For each real number $\Lambda$ a Lie algebra of nonlinear vector fields on three dimensional Euclidean space is reported. Although each algebra is mathematically isomorphic to $gl(3,{\bf R})$, only the $\Lambda=0$ vector fields correspond to the usual generators of the general linear group. The $\Lambda < 0$ vector fields integrate to a nonstandard action of the general linear group; the $\Lambda >0$ case integrates to a local Lie semigroup. For each $\Lambda$, a family of surfaces is identified that is invariant with respect to the group or semigroup action. For positive $\Lambda$ the surfaces describe fissioning nuclei with a neck, while negative $\Lambda$ surfaces correspond to exotic bubble nuclei. Collective models for neck and bubble nuclei are given by irreducible unitary representations of a fifteen dimensional semidirect sum spectrum generating algebra $gcm(3)$ spanned by its nonlinear $gl(3,{\bf R})$ subalgebra plus an abelian nonlinear inertia tensor subalgebra.Comment: 13 pages plus two figures(available by fax from authors by request

A study of Association of Mast Cell Count in Different Grades of Oral Squamous Cell Carcinoma

Background: Mast cells(MC) are cells of the immune cells which can secrete a variety of molecules. Many studies suggest that mast cells may either promote tumour growth in some types of cancer or may act in an opposite manner in other tumour types. Aim: To evaluate the association of mast cells in the different grades of Oral Squamous Cell Carcinoma(OSCC). Material and methods: Fifteen diagnosed cases each of well, moderate and poorly differentiated OSCC were identified from the institutional archival material. Two slides each were made of 5 μm thickness and stained with Hematoxylin and eosin and 1% Toluidine blue stain. Each section was evaluated for mast cells in peritumoural, intratumoural locations and at the invasive front of the tumour. The results obtained were subjected to statistical evaluation by an SPSS version 19 using Chi square test, Anova and Post hoc Tuckey tests. Results: An inverse relation was observed between MC count with grade of the tumour with maximum MC located in the peritumoural area followed by the invasive front and the least in the intra tumoural areas. Conclusion: The results of the present study suggest that a decrease in MC count is associated with an advanced histologic grade of OSCC and hence a poorer prognosis, thus favouring the protective role of mast cells in OSCC.Keywords: Mast cells, Oral squamous cell carcinoma, Histological gradin

Increased Prevalence of Activated Protein C Resistance During Pregnancy may Implicate Venous Thrombo Embolic Disorders as a Common Cause of Maternal Mortality in Nigeria

Background: Acquired resistance to protein C in pregnancy has been established as one of the factors associated with thromboembolic phenomenon, an important cause of maternal mortality and morbidity.Objectives: To establish the mean levels of PCA ratio (measure of protein C resistance) of among our pregnant women since maternal mortality rate of the country is on the increase despite efforts to reduce this trend.Materials and Methods: A prospective study was carried out in a tertiary institution in Enugu State, Southeastern Nigeria over the 7 months period from May 2010 to November 2010. Two hundred pregnant women and 50 non pregnant female controls were recruited and PCA ratio, (coagulometric assay) were determined. Results: There was a non significant difference between the mean and standard deviation PCA ratio of the female non pregnant controls and pregnant women in 2nd trimester 4.32±0.4 and 4.30±0.4 respectively. A significant difference was noted between the controls and pregnant women in 3rd trimester 4.32±0.4 and 3.87±0.5 respectively also between the pregnant women in their 2nd and 3rd trimester 4.30±0.4 and 3.87±0.5 respectively.Conclusion: There is increased protein resistance C in our pregnant women. This may implicate thromboembolic disorders as one of the leading causes of increase maternal mortality despite a downward trend in the prevalence of post partum haemorrhage.Keywords: Acquired protein C resistance, maternal mortality, pregnancy, post partum hemorrhage, thromboembolic disorder

Structural Basis for Potentiation by Alcohols and Anaesthetics in a Ligand-gated Ion Channel

Ethanol alters nerve signalling by interacting with proteins in the central nervous system, particularly pentameric ligand-gated ion channels. A recent series of mutagenesis experiments on Gloeobacter violaceus ligand-gated ion channel, a prokaryotic member of this family, identified a single-site variant that is potentiated by pharmacologically relevant concentrations of ethanol. Here we determine crystal structures of the ethanol-sensitized variant in the absence and presence of ethanol and related modulators, which bind in a transmembrane cavity between channel subunits and may stabilize the open form of the channel. Structural and mutagenesis studies defined overlapping mechanisms of potentiation by alcohols and anaesthetics via the inter-subunit cavity. Furthermore, homology modelling show this cavity to be conserved in human ethanol-sensitive glycine and GABA(A) receptors, and to involve residues previously shown to influence alcohol and anaesthetic action on these proteins. These results suggest a common structural basis for ethanol potentiation of an important class of targets for neurological actions of ethanol