Inference on Risk Rates Based on Mortality Data Under Censoring and Competing Risks Using Parametric Models

In this paper we consider the competing risks model where the risks may not be independent. We assume both fixed and random censoring. The random censoring mechanism could have either a parametric or a non-parametric form. The life distributions and the parametric censoring distribution considered are exponential or Weibull. The expressions for the asymptotic confidence intervals for various parameters of interest under different models, using the estimated Fisher information matrix and parametric bootstrap techniques have been derived. Monte Carlo simulation studies for some of these cases have been carried out.     

Histopathological correlations of bulk tissue polarimetric images: Case study

Polarimetric imaging and image analysis have gained increased interest in soft tissue analysis at the cellular level. However, polarimetric imaging has widely been tested on thin tissue sections to provide reliable information correlated with histopathological findings. Polarimetric bulk tissue analysis always offered an overall assessment of various tissue optical properties for diagnosis. In this study, the histopathological correlation of bulk tissue polarimetry images for soft tissues is discussed. The first-hand information on the use of bulk tissue Mueller polarimetry and image analysis as an alternative to tissue histopathology is presented for surgically extracted colon and breast tissues.     

Expression of the cry1EC gene in castor (Ricinus communis L.) confers field resistance to tobacco caterpillar (Spodoptera litura Fabr) and castor semilooper (Achoea janata L.)

Castor (cv. DCS-9) has been transformed through Agrobacterium-mediated and particle gun bombardment methods using appropriate vectors containing the Bt chimeric gene cry1EC driven by enhanced 35S promoter. About 81 and 12 putative transformants were regenerated following selection on hygromycin and kanamycin, respectively. Southern analysis of DNA extracted from T₀ plants confirmed integration of the introduced gene in castor genome. The integration and inheritance of the introduced genes was demonstrated up to T₄ generation by PCR and Southern analysis. Southern analysis of two events having single and two copies showed the same pattern of integration in the subsequent generations. Insect feeding experiments conducted in the laboratory by releasing neonate larvae of castor semilooper and S. litura on leaf tissues excised from transgenic and control plants showed varying degrees of larval mortality and slow growth in larvae fed on transgenic leaf tissue. Field bioassays against Spodoptera litura and castor semilooper conducted for eight events in T₁–T₄ generations under net confinement were more informative and events conferring resistance to the two major defoliators were identified.     

Diurnal depth-wise and seasonal changes of physico-chemical factors in Sathiar reservoir

The various physico-chemical factors such as rainfall, depth, water spread, temperature, dissolved oxygen, pH, redox potential, alkalinity, total phosphorus, nitrate, kjeldahl nitrogen and dissolved organic matter were studied both diurnally and seasonally and depth-wise for the period from April 1977 to March 1978. Consideration of physico-chemical factors indicates that they are inter-related. The main characteristics of Sathiar clearly indicate that it is highly eutrophic.     

Structure of presynaptic toxins: Crystallization and preliminary x-ray diffraction data on Notechis II-5, a presynaptic toxin phospholipase

The presynaptic neutrotoxin-phospholipase, Notechis II-5 from the venom of NotechisScutatus scutatus (Australian tiger snake) has been crystallized in a form suited for x-ray diffraction analysis. The crystals belong to the orthorhombic space group P2₁ 2₁,2₁, with unit cell dimensions, a=146.1,b =43.5 and c =39.0 A. There are two molecules of Notechis II-5 in the asymmetric unit. The molecular weight is about 13,500. Notechis II-5 is highly homologous to Notexin, another presynaptic toxin from the venom of the Australian tiger snake, to bovine and porcine pancreatic phospholipases A and other venom phospholipases.     

GSH Transport in Immortalized Mouse Brain Endothelial Cells

We have previously shown GSH transport across the blood-brain barrier in vivo and expression of transport in Xenopus laevis oocytes injected with bovine brain capillary mRNA. In the present study, we have used MBEC-4, an immortalized mouse brain endothelial cell line, to establish the presence of Na+-dependent and Na+-independent GSH transport and have localized the Na+-dependent transporter using domain-enriched plasma membrane vesicles. In cells depleted of GSH with buthionine sulfoximine, a significant increase of intracellular GSH could be demonstrated only in the presence of Na+. Partial but significant Na+ dependency of [35S]GSH uptake was observed for two GSH concentrations in MBEC-4 cells in which gamma-glutamyltranspeptidase and gamma-glutamylcysteine synthetase were inhibited to ensure absence of breakdown and resynthesis of GSH. Uniqueness of Na+-dependent uptake in MBEC-4 cells was confirmed with parallel uptake studies with Cos-7 cells that did not show this activity. Molecular form of uptake was verified as predominantly GSH, and very little conversion of [35S]cysteine to GSH occurred under the same incubation conditions. Poly(A)+ RNA from MBEC expressed GSH uptake with significant (approximately 40-70%) Na+ dependency, whereas uptake expressed by poly(A)+ RNA from HepG2 and Cos-1 cells was Na+ independent. Plasma membrane vesicles from MBEC were separated into three fractions (30, 34, and 38% sucrose, by wt) by density gradient centrifugation. Na+-dependent glucose transport, reported to be localized to the abluminal membrane, was found to be associated with the 38% fraction (abluminal). Na+-dependent GSH transport was present in the 30% fraction, which was identified as the apical (luminal) membrane by localization of P-glycoprotein 170 by western blot analysis. Localization of Na+-dependent GSH transport to the luminal membrane and its ability to drive up intracellular GSH may find application in the delivery of supplemented GSH to the brain in vivo.     

Plant Regeneration from Leaf Explants of Three Grain Legumes on Same Medium

The regeneration potential of leaves of moth bean, pigeonpea and grass pea was studied on Murashige and Skoog’s (MS) medium supplemented with various combinations of auxins and cytokinins. Regeneration of shoots was obtained mainly on MS medium supplemented with high auxin and low cytokinin levels. However, frequency of response varied not only in the three legume species but also in their varieties studied. Roots were induced on regenerated shoots by transferring them to MS basal medium. Complete plant regeneration was observed in the three legumes in a short duration of 60–70 days.     

A Markov chain analysis of predator strategy in a model-mimic system

A predator which is preying on a model-mimic system can choose either the single-trial strategy or a multi-trial strategy as its behavior in learning to prudently harvest such a prey system. In this learning behavior, an important and often-posed problem is to determine which among these two strategies is better suited for the predator and why one is preferable over the other. We present in this article, using Markov chain methods, an extensive analysis of these strategies (and also of eat-everything, strategy). We conclude that the multi-trial strategy is the one that the predator should adopt (but we will also describe the situations when the single-trial strategy seems to be better). Our conclusions are based on the comparisons of quantities such as the mean benefit to the predator, energy derived by a predator from the model-mimic system and (a newly introduced notion of) contagion in eating mimics and models (these quantities are computed for different strategies). The first two quantities are functions of the abundancep and noxiousnessb of models. The contagion is a function of onlyp; and, though independent ofb, it is also in support of multi-trial, strategy. We introduce, in the present context, a biological analog of the d'Alembert principle and also derive functions describing the influences of eating a specified type of prey at a given time on eating any type of prey at a later time. Various results of Estabrook-Jespersen (single-trial strategy) and Bobisud-Potratz (multi-trial strategy) are re-derived as special cases of our more general results. A central limit theorem under the eat-everything strategy is given.     

One-pot synthesis of highly functionalized morphans from C-glycosides

Highly functionalized morphan derivatives were synthesized from nitroalkene 2′-(oxoalkyl)-C-glycosides by a tandem reaction that created three (two C–N and one C–C) new bonds and four stereogenic centers in a one-pot procedure under very mild conditions without the use of expensive reagents. The transformation was achieved from a β-elimination/Michael addition cascade, followed by Michael addition of the amine and intramolecular enamination. In the presence of sodium cyanoborohydride the iminium intermediate was reduced in situ to afford the desired morphans.