Further studies on the sensitivity of plant pathogenic microorganisms towards some naturally occurring chalcones and flavanones

Summary The antifungal and antibacterial activities of some quinochalcones, chalcones and flavanones isolated fromDidymocarpus pedicellata have been assayed.The authors are grateful to B.C.K.V.V. and CSIR, India, for financial assistance.     

Hormetic concentrations of azadirachtin and isoesterase profiles inTribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Electrophoretic pattern of esterases from larvae ofTribolium castaneum fed on a diet which included hormetic concentrations of azadirachtin (viz. 0.001, 0.01 and 0.1 ppm) for 10 d were studied. The results showed a dose-dependent variation in the multiple molecular forms of the esterases. The variations, however, were not limited to the synthesis of new isoforms or the deletion of existing ones; there was also variation in their relative abundance.     

RIM1alpha forms a protein scaffold for regulating neurotransmitter release at the active zone.

Neurotransmitters are released by synaptic vesicle fusion at the active zone. The active zone of a synapse mediates Ca2+-triggered neurotransmitter release, and integrates presynaptic signals in regulating this release. Much is known about the structure of active zones and synaptic vesicles, but the functional relation between their components is poorly understood. Here we show that RIM1alpha, an active zone protein that was identified as a putative effector for the synaptic vesicle protein Rab3A, interacts with several active zone molecules, including Munc13-1 (ref. 6) and alpha-liprins, to form a protein scaffold in the presynaptic nerve terminal. Abolishing the expression of RIM1alpha in mice shows that RIM1alpha is essential for maintaining normal probability of neurotransmitter release, and for regulating release during short-term synaptic plasticity. These data indicate that RIM1alpha has a central function in integrating active zone proteins and synaptic vesicles into a molecular scaffold that controls neurotransmitter release.     

Prediction of central nervous system embryonal tumour outcome based on gene expression.

Embryonal tumours of the central nervous system (CNS) represent a heterogeneous group of tumours about which little is known biologically, and whose diagnosis, on the basis of morphologic appearance alone, is controversial. Medulloblastomas, for example, are the most common malignant brain tumour of childhood, but their pathogenesis is unknown, their relationship to other embryonal CNS tumours is debated, and patients' response to therapy is difficult to predict. We approached these problems by developing a classification system based on DNA microarray gene expression data derived from 99 patient samples. Here we demonstrate that medulloblastomas are molecularly distinct from other brain tumours including primitive neuroectodermal tumours (PNETs), atypical teratoid/rhabdoid tumours (AT/RTs) and malignant gliomas. Previously unrecognized evidence supporting the derivation of medulloblastomas from cerebellar granule cells through activation of the Sonic Hedgehog (SHH) pathway was also revealed. We show further that the clinical outcome of children with medulloblastomas is highly predictable on the basis of the gene expression profiles of their tumours at diagnosis.     

Mineralogy and carbothermal reduction behaviour of vanadium-bearing titaniferous magnetite ore in Eastern India

Vanadium-bearing titaniferous magnetite bands hosted by Precambrian gabbro-norite-anorthositic rocks or their metamorphic equivalents were discovered in some parts of Eastern Indian Shield, containing 48%–49% Fe (total), 10%–25% TiO₂, and 0.3%–2.20% V₂O₅ by mass. Mineralogical and petrological study, composition, and characterization of the vanadium-bearing titaniferous magnetite ore were carried out by scanning electron microscopy-energy dispersive X-ray (SEM-EDX), wave length X-ray florescence (WDXRF), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), X-ray diffraction (XRD), etc. Chemical beneficiation for valuable metals, such as Fe, Ti, and V, was performed by reduction roasting. The direct and indirect reduction were investigated by mixing the lump ore with solid activated charcoal in a closed reactor and purging the reducing gas mixture in standard reducibility index apparatus at different temperatures and time intervals. The reduction roasting parameters were optimized. Finally, the reduced samples were crushed and upgraded by magnetic separation. The results show that, the maximum mass fractions of magnetic and nonmagnetic parts achieved are 69.36% and 30.64%, respectively, which contain 10.6% TiO₂ and 0.84% V₂O₅ in the magnetic part and 36.5% TiO₂ and 0.22% V₂O₅ in the nonmagnetic part.     

模糊完全连续函数的某些弱形式

作为模糊完全连续函数的推广，本文在模糊拓扑空间中引入了两类函数──模糊半完全连续函数和模糊半强θ──连续函数．这两类函数介于由Ｍｕｋｈｅｒｊｅｅ和ＧｈｏＳｈ最近引入的模糊完全连续函数和模糊强θ──连续函数之间．初究了这些函数的某些性质．     

Evaluation of factors affecting the edge formability of two hot rolled multiphase steels

In this study, the effect of various factors on the hole expansion ratio and hence on the edge formability of two hot rolled multiphase steels, one with a ferrite-martensite microstructure and the other with a ferrite-bainite microstructure, was investigated through systematic microstructural and mechanical characterization. The study revealed that the microstructure of the steels, which determines their strain hardening capacity and fracture resistance, is the principal factor controlling edge formability. The influence of other factors such as tensile strength, ductility, anisotropy, and thickness, though present, are secondary. A critical evaluation of the available empirical models for hole expansion ratio prediction is also presented.