亨施自述

在我们极其复杂和不断变化的世界里，知悉某些物理量能用很高的精确度来测量和预言，是一件人欣慰的事。精确测量作为物理学中最美的一个方面永远吸引着我。使用更好的测量工具，人们能够看到以前无人见过的地方。不止一次，测量值与理论值之间似乎微不足道的差异导致了基础知识领域里的重要进展。现代科学的诞生本身便是与精确的测量技术密切相关。     

Mutations in genes encoding melanosomal proteins cause pigmentary glaucoma in DBA/2J mice.

Pigmentary glaucoma is a significant cause of human blindness. Abnormally liberated iris pigment and cell debris enter the ocular drainage structures, leading to increased intraocular pressure (IOP) and glaucoma. DBA/2J (D2) mice develop a form of pigmentary glaucoma involving iris pigment dispersion (IPD) and iris stromal atrophy (ISA). Using high-resolution mapping techniques, sequencing and functional genetic tests, we show that IPD and ISA result from mutations in related genes encoding melanosomal proteins. IPD is caused by a premature stop codon mutation in the Gpnmb (GpnmbR150X) gene, as proved by the occurrence of IPD only in D2 mice that are homozygous with respect to GpnmbR150X; otherwise, similar D2 mice that are not homozygous for GpnmbR150X do not develop IPD. ISA is caused by the recessive Tyrp1b mutant allele and rescued by the transgenic introduction of wildtype Tyrp1. We hypothesize that IPD and ISA alter melanosomes, allowing toxic intermediates of pigment production to leak from melanosomes, causing iris disease and subsequent pigmentary glaucoma. This is supported by the rescue of IPD and ISA in D2 eyes with substantially decreased pigment production. These data indicate that pigment production and mutant melanosomal protein genes may contribute to human pigmentary glaucoma. The fact that hypopigmentation profoundly alleviates the D2 disease indicates that therapeutic strategies designed to decrease pigment production may be beneficial in human pigmentary glaucoma.     

Microsatellites are preferentially associated with nonrepetitive DNA in plant genomes.

Microsatellites are a ubiquitous class of simple repetitive DNA sequence. An excess of such repetitive tracts has been described in all eukaryotes analyzed and is thought to result from the mutational effects of replication slippage. Large-scale genomic and EST sequencing provides the opportunity to evaluate the abundance and relative distribution of microsatellites between transcribed and nontranscribed regions and the relationship of these features to haploid genome size. Although this has been studied in microbial and animal genomes, information in plants is limited. We assessed microsatellite frequency in plant species with a 50-fold range in genome size that is mostly attributable to the recent amplification of repetitive DNA. Among species, the overall frequency of microsatellites was inversely related to genome size and to the proportion of repetitive DNA but remained constant in the transcribed portion of the genome. This indicates that most microsatellites reside in regions pre-dating the recent genome expansion in many plants. The microsatellite frequency was higher in transcribed regions, especially in the untranslated portions, than in genomic DNA. Contrary to previous reports suggesting a preferential mechanism for the origin of microsatellites from repetitive DNA in both animals and plants, our findings show a significant association with the low-copy fraction of plant genomes.     

黄酮类化合物清除对苯半醌负离子自由基研究(Ⅰ)

以对苯半醌负离子自由基为模型 ,利用ESR技术研究黄酮类化合物清除自由基的作用 ,初步获得一些构效关系。     

应用激光闪光法测量薄膜材料的热扩散率

目的是将用于测量片状试样的热扩散率的激光闪光法推广至测量薄膜试样。应用 1 5纳秒脉冲 Nd:YAG激光及响应时间 0 .9微秒的 (Hg,Cd) Te红外探测器等建立了闪光法热扩散率测量系统 ,并应用此系统对微米量级厚度的不锈钢薄膜进行了测量。同时针对将激光闪光法应用于薄膜时所出现的问题 ,如激光的有限脉冲时间及有限吸收厚度效应 ,测量系统的滞后效应 ,以及增强红外吸收及辐射用表面黑化膜的影响进行了分析并提出了解决方法     

Palaeolake and palaeoenvironment between 42 and 18 kaBP in tengger desert, NW China

Comprehensive field investigations and laboratory analyses show that palaeolakes, including fresh- mesohaline water Megalake Tengger and other semi-con- nected, isolated water bodies, during late Pleistocene covered an area of more than 20000 km², which is more than half of the Tengger Desert in NW China. Stratigraphic correlation and chronological evidence indicate that before ca. 42000 aBP the area was more arid. The palaeolakes started to develop around 40000 uncal. ¹⁴C aBP but until 37000 ¹⁴C aBP their scope was limited. High water levels established from 35000 ¹⁴C aBP lasted until 22000 ¹⁴CaBP. Lake levels regressed between 22000 and 20000 ¹⁴C aBP but transgressed from 20000 to 18600 ¹⁴C aBP. Subsequently, water level declined further and the Megalake Tengger finally desiccated at around 18000 ¹⁴C aBP. Megalake Tengger possessed a fresh-mesohaline water property, implying that the regional precipitation increased significantly. During the period of Megalake Tengger, the climate was warmer-humid than present. The annual rainfall was 250 to 350 mm more than that of today and the temperature was 1.5 to 3.0℃ higher.     

Zircon (U-Th)/He thermochronological constraints on Cretaceous thermal extension of Dabieshan orogen

：(U-Th)/He ages of 13 samples from Yuexi-Luotian core and its flanks in Dabieshan orogen fall in the range of 155～85 Ma. He ages for samples from the core range between 85～107 Ma, while those from the flanks range between 114～155 Ma. The result shows that the Yuexi-Luotian core was a thermal dome in Cretaceous with core temperature being much higher than those of the flanks. The thermal extension which resulted in the formation of Dabie core complex lasted until ca. 85 Ma. The magnitude of exhumation in the core is approximately 1528.8 m more than that in the flanks.     

神经模糊网络自适应模糊控制研究

提出了一种由样品辨识、模糊推理和控制处理 3个子网模块构成的基于知识的多层神经网络 .这种网络由各子网分别构成并按照最初的模糊控制结构适当连接而建立 ,具有明确区分各组成子网功能及其知识流结构 .由于综合了模糊逻辑的推理过程及神经网络的学习能力 ,使它能够在其结构中以模糊规则的形式引入语言知识并通过网络的训练及自学习对这些知识进行加工 ,从而实现了真正意义上的自适应模糊控制器 .最后还讨论了这种 NFN网络在动态过程控制中的应用     

Timed bromocriptine administration reduces body fat stores in obese subjects and hyperglycemia in type II diabetics

Obese postmenopausal female volunteers were given timed daily oral dosages of bromocriptine, and tested for reduction of body fat stores. This dopamine agonist has been shown to reset circadian rhythms that are altered in obese animals and to reduce body fat levels in several animal models. The participants were instructed not to alter their existing exercise and eating behavior during treatment. Skinfold measurements were taken on 33 subjects as indices of body fat. The measurements (e.g., suprailiac) were reduced after six weeks by about 25%, which represents a reduction of 11.7% of the total body fat. These dramatic decreases in body fat, which are equivalent to that produced by severe caloric restriction, were accompanied by more modest reductions of body weight (2.5%), indicating a possible conservation of protein that is usually lost as a consequence of such caloric restriction. The effects of bromocriptine treatment on body fat and hyperglycemia were also examined in non-insulin dependent diabetics being treated with oral hypoglycemics (7 subjects) or insulin (7 subjects). Total body fat was reduced by 10.7% and 5.1% in diabetics on oral hypoglycemics and insulin, respectively, without any significant reductions in body weight.Hyperglycemia was reduced in most of the 15 diabetic subjects treated leading to euglycemia and even cessation of hypoglycemic drugs in 3 of the 7 subjects during 4–8 weeks of bromocriptine treatment. These findings support the hypothesis that obesity and type II diabetes may be treated effectively with bromocriptine when administered at the proper times and dosages.This is a process patented by Louisiana State University and licensed to Ergo, Inc., Newport, Rhode island. A. H. Meier and A. H. Cincotta have financial interest in the process.