Functional waters in intraprotein proton transfer monitored by FTIR difference spectroscopy

Much progress has been made in our understanding of water molecule reactions on surfaces, proton solvation in gas-phase water clusters and proton transfer through liquids. Compared with our advanced understanding of these physico-chemical systems, much less is known about individual water molecules and their cooperative behaviour in heterogeneous proteins during enzymatic reactions. Here we use time-resolved Fourier transform infrared spectroscopy (trFTIR) and in situ H2(18)O/H2(16)O exchange FTIR to determine how the membrane protein bacteriorhodopsin uses the interplay among strongly hydrogen-bonded water molecules, a water molecule with a dangling hydroxyl group and a protonated water cluster to transfer protons. The precise arrangement of water molecules in the protein matrix results in a controlled Grotthuss proton transfer, in contrast to the random proton migration that occurs in liquid water. Our findings support the emerging paradigm that intraprotein water molecules are as essential for biological functions as amino acids.     

Discovery of very-high-energy gamma-rays from the Galactic Centre ridge

The source of Galactic cosmic rays (with energies up to 10(15) eV) remains unclear, although it is widely believed that they originate in the shock waves of expanding supernova remnants. At present the best way to investigate their acceleration and propagation is by observing the gamma-rays produced when cosmic rays interact with interstellar gas. Here we report observations of an extended region of very-high-energy (> 10(11) eV) gamma-ray emission correlated spatially with a complex of giant molecular clouds in the central 200 parsecs of the Milky Way. The hardness of the gamma-ray spectrum and the conditions in those molecular clouds indicate that the cosmic rays giving rise to the gamma-rays are likely to be protons and nuclei rather than electrons. The energy associated with the cosmic rays could have come from a single supernova explosion around 10(4) years ago.     

哈尔滨市城市公园POE应用案例研究

本文运用POE（post occupancy evaluation）基本研究方法，对哈尔滨市城市公园进行了案例调查研究。通过观察公园使用者的各类活动．采访公园的使用者以及发放抽样调查问卷等形式，了解哈尔滨市公园的使用状况，并对调查所获信息和数据分析、整理，找出哈尔滨市城市公园的现存问题，提出优化设计与管理建议。该调查可为哈尔滨市城市公园改善、提高设计、使用和管理水平提供依据．也可为其它类似公园的设计提供借鉴。     

有志者事竟成

“地震、火灾、海啸、风暴、火山爆发、战争——天灾人祸在所难免,过去、现在和将来都会发生。但是,我们知道怎样做才能尽可能减少天灾人祸的后果,把天灾人祸造成的破坏保持在可以接受的程度,并尽可能完美地修复遭到毁坏的艺术作品。这需要最高水平的政府和行政支持,需要精心规划,当然还需要钱——令人惊异的是并不需要太多的钱。然     

一个为普及空间科学知识奋斗的人

他是在广播节目影响下确定自己的职业选择的。墨迪波缔雅拉在一个名叫塞古的马里小城长大的,小时候,他特别喜欢收听美国之音的每周科技节目。墨迪波回忆说。"阿波罗登月的时候,我们那里还没有电视。" 现在,46岁的墨迪波·缔雅拉谢赫成了美国宇航局火星观察者项目首席领航员,他和队友们一道共同负责去年7月4日把先锋号宇宙探测器送上火星的那个项目。不久前,联合国教科文组织任命他为"友好大使"。     

Shrinkage Properties of Wool and Acrylic/Wool Plain Knitted Fabrics Treated with DC109

This paper examines the effects of shrink - resist treatment, washing cycle and fabric tightness on the shrinkage properties of plain knitted fabrics made from 100% wool, acrylic/wool (50/50) and acrylic/wool (70/30). It was found that shrinkages of both treated and untreated wool fabrics were negatively correlated to fabric tightness and exceeded the IWS shrinkage limits (5% in length and 8 % in area) after 2 - 5A washing cycle. The effect of tightness was not as obvious with acrylic/wool (A/W) fabrics, but the shrinkage was seen to increase with stages of washing cycle for untreated A/W fabrics with some exceeding IWS standard. By applying the DC 109 shrink - resist solvent treatment, it was identified that by with higher percentage of acrylic fibre blended with wool, shrinkage could be reduced considerably and within acceptable limits.     

The RNA splicing factor hSlu7 is required for correct 3' splice-site choice

The production of correctly spliced messenger RNA requires two catalytic splicing steps. During step II, exon 1 attacks an adenine-guanine (AG) dinucleotide at the 3' splice site. This AG is usually located between 18 and 40 nucleotides downstream from the branch site, and closer AGs are skipped in favour of AGs located more optimally downstream. At present, little is understood about how the correct AG is distinguished from other AGs. Here we describe a metazoan splicing factor (hSlu7) that is required for selection of the correct AG. In the absence of hSlu7, use of the correct AG is suppressed and incorrect AGs are activated. We investigated this loss of fidelity by analysing spliceosomes assembled in the absence of hSlu7. These studies reveal that exon 1 is loosely associated with these spliceosomes. Thus, the improperly held exon cannot access the correct AG, but can attack other AGs indiscriminately. We conclude that hSlu7 is required to hold exon 1 tightly within the spliceosome for attack on a prespecified AG.