Superconductivity and the d-Shell

The various isotope effects on the superconducting transition temperature of Mo(2)B and W(2)B have been measured. Together with resistivity data they indicate that the d-shell forms a highly stable electron configuration for molybdenum and tungsten. This leads to an understanding of high superconducting transition temperatures.     

Editing of CD1d-bound lipid antigens by endosomal lipid transfer proteins

It is now established that CD1 molecules present lipid antigens to T cells, although it is not clear how the exchange of lipids between membrane compartments and the CD1 binding groove is assisted. We report that mice deficient in prosaposin, the precursor to a family of endosomal lipid transfer proteins (LTP), exhibit specific defects in CD1d-mediated antigen presentation and lack Valpha14 NKT cells. In vitro, saposins extracted monomeric lipids from membranes and from CD1, thereby promoting the loading as well as the editing of lipids on CD1. Transient complexes between CD1, lipid, and LTP suggested a "tug-of-war" model in which lipid exchange between CD1 and LTP is on the basis of their respective affinities for lipids. LTPs constitute a previously unknown link between lipid metabolism and immunity and are likely to exert a profound influence on the repertoire of self, tumor, and microbial lipid antigens.     

舒适性空调节能系统的设计与试验研究

人体热舒适度和PMV指标有很大关系,即人体热舒适度不仅仅只与空气温度有关,还和其他一些环境因素有很大关系,因此只调整室内空气温度,达不到人体热舒适度的要求,必须还要相应得调整其他环境因素。在CFD模拟仿真的基础上,研究出一种新型的"风扇-灯"来改善室内环境。试验证明,利用此装置可以在升高室内温度的同时保证人体的热舒适度,达到了节能和热舒适度两方面的要求。     

Avian H5N1 influenza in cats

During the 2003 to 2004 outbreak of avian influenza A (H5N1) virus in Asia, there were anecdotal reports of fatal infection in domestic cats, although this species is considered resistant to influenza. We experimentally inoculated cats with H5N1 virus intratracheally and by feeding them virus-infected chickens. The cats excreted virus, developed severe diffuse alveolar damage, and transmitted virus to sentinel cats. These results show that domestic cats are at risk of disease or death from H5N1 virus, can be infected by horizontal transmission, and may play a role in the epidemiology of this virus.     

Synchronized oscillation in coupled nanomechanical oscillators

We report measurements of synchronization in two nanomechanical beam oscillators coupled by a mechanical element. We charted multiple regions of frequency entrainment or synchronization by their corresponding Arnold's tongue diagrams as the oscillator was driven at subharmonic and rational commensurate frequencies. Demonstration of multiple synchronized regions could be fundamentally important to neurocomputing with mechanical oscillator networks and nanomechanical signal processing for microwave communication.     

Massive-star supernovae as major dust factories

We present late-time optical and mid-infrared observations of the Type II supernova 2003gd in the galaxy NGC 628. Mid-infrared excesses consistent with cooling dust in the ejecta are observed 499 to 678 days after outburst and are accompanied by increasing optical extinction and growing asymmetries in the emission-line profiles. Radiative-transfer models show that up to 0.02 solar masses of dust has formed within the ejecta, beginning as early as 250 days after outburst. These observations show that dust formation in supernova ejecta can be efficient and that massive-star supernovae could have been major dust producers throughout the history of the universe.