Melatonin biosynthesis in the thymus of humans and rats

Melatonin is an indoleamine widely distributed in the evolution that shows a great functional versatility, playing an important role as a transmitter of photoperiodic information and exhibiting antioxidant, oncostatic, anti-aging and immunomodulatory properties. In vertebrates, this molecule is produced by the pineal gland and other extrapineal sites. The present study was carried out to investigate the presence of melatonin in thymus and the possibility of an endogenous melatonin synthesis in this organ, in which T cells are matured. In this work, we demonstrate in humans and rats that thymus contains melatonin, expresses the mRNAs encoding N-acetyltransferase and hydroxyindol-O-methyltransferase, the two key enzymes of the melatonin synthesis, and has this biosynthetic machinery activated. In addition, rat thymocytes cultured for 24 h exhibited high levels of melatonin. The results presented here suggest that human and rat thymuses are able to synthesize melatonin, which could have intracrine, autocrine and paracrine functions. Received 30 September 2006; received after revision 30 December 2006; accepted 15 February 2007     

Optical detection of meteoroidal impacts on the Moon

Impacts of meteoroids on the Moon should cause detectable optical flashes, but the population of objects that are big enough is very low, and hitherto no unambiguous impact flashes have been recorded. The flux of meteoroids associated with the Leonid meteor shower of 18 November 1999 was predicted to produce observable flashes on the night side of the Moon. Here we report the unambiguous detection of five such impact flashes, three of which were seen simultaneously by other observers. We also observed a possible impact flash on 16 July 1999. All of the flashes were of very brief duration (<0.02 s), as expected for high-speed impacts.     

Mendelian recessive ratios in acute poststreptococcal glomerulonephritis

Summary A prospective study of 15 families (61 siblings) of index cases of acute poststreptococcal glomerulonephritis detected a proportion of 0.260±0.016 SEM. This is an excellent fit for a single autosomal recessive trait.This study was supported by CONICIT grants SAL-S1-001 and 3126-S1-0663 (Venezuela) and Grants in Aid from CONDES (Universidad del Zulia) and Asociacion de Amigos del Riñón (Maracaibo).     

Caving performance through the integration of microseismic activity and numerical modeling at DOZ-PT Freeport, Indonesia

This article describes an undergoing research at PT Freeport, Indonesia, in which the main goal is to use the microseismic information recorded as a result of mining to analyze cave propagation and stress performance on the actual production and fixed infrastructure. At the moment, several numerical experiments have been conducted to correlate the mining activity with the microseismic events using the data collected during year 2005 and 2006. As a result of the preliminary analysis a micro- and a macrocracking envelop were proposed on the basis of computation of stress behavior at the location of the events. Stresses have been computed using standard elastic continuous boundary element models. The correlation between the average source radius and the stress performance has provided a method to propose a macrocracking criterion. Several techniques have been tested to nucleate the microseismic activity around different geological features. This last attempt was aimed to look at potential overstresses induced over the undercut and extraction level drifts. A method was devised to integrate the microseismicity into a 3-dimensional ride distribution model. This model has shown to be very effective to quantify the overstress induced as a result of computing volumetric microseismicity density. The volumetric microseismic model showed to induce overstress up to 10 MPa over a period of two months. The future work will concentrate on the calibration of the integrated model with actual damage observations made at the current mining infrastructure.     

解体好氧颗粒污泥修复

考察了加入新的活性污泥使解体好氧颗粒污泥完成修复的可行性.解体好氧颗粒污泥对新加入的活性污泥进行吸附,在各种选择压力特别是水力剪切力作用下和原有颗粒污泥形成一个有机整体.大约3周时间,解体颗粒污泥被完全修复.扫描电镜观察发现,被修复后的颗粒污泥呈现非常规则的结构,微生物相十分致密.在解体颗粒污泥逐渐被修复的过程中,颗粒平均粒径仅从最初的2.8mm增至2.9mm,说明活性污泥在颗粒污泥上的附着主要发生在颗粒的空穴.而颗粒污泥的沉降性能和强度都得到了极大的改善,颗粒沉降速率和完整性系数分别由最初的72m/h和56.8%提高到110m/h和65.8%.新加入的活性污泥除了部分用于修复解体颗粒污泥,其余在选择压力等的作用下形成了新的好氧颗粒污泥.     

A conserved sorting-associated protein is mutant in chorea-acanthocytosis

Chorea-acanthocytosis (CHAC, MIM 200150) is an autosomal recessive neurodegenerative disorder characterized by the gradual onset of hyperkinetic movements and abnormal erythrocyte morphology (acanthocytosis). Neurological findings closely resemble those observed in Huntington disease. We identified a gene in the CHAC critical region and found 16 different mutations in individuals with chorea-acanthocytosis. CHAC encodes an evolutionarily conserved protein that is probably involved in protein sorting.     

An interpretation of some bristle pattern modifications caused by directional selection inDrosophila melanogaster

Summary The variations of the dorsocentral and scutellar bristle patterns founded in two bidirectionaly selected lines are discussed in terms of the Richelle and Ghysen model. The phenotype obtained through selection for bristle suppression can be accounted for by a decrease in chaetogen production. Extra bristles can be accounted for by an alteration of the response of the cells to positional information.