Phase-Plane Invariant Analysis of Pressure Fluctuations in Fluidized Beds

Partial agglomeration is a major problem in fluidized beds. A chaotic analytical method based on the phase-plane invariant of the pressure fluctuations in the fluidized beds has been used to warn of ag-glomeration at an early stage. Cold tests (no combustion) and hot tests (combustion) in fluidized beds show that the phase-plane invariant of the pressure fluctuations can distinguish the dynamic behavior of fluidized beds with different flow rates in cold tests. With combustion, when the flow rate was kept constant, agglom-eration was detected very early by looking at the phase-plane invariant. The phase-plane invariant can be used to distinguish changes in fluidized beds due to changes in the flow rate, agglomeration, or various other factors. Therefore, this reliable agglomeration early warning system can be used for better control of circulating fluidized beds.     

Structural basis for specific cleavage of Lys 63-linked polyubiquitin chains

Deubiquitinating enzymes (DUBs) remove ubiquitin from conjugated substrates to regulate various cellular processes. The Zn(2+)-dependent DUBs AMSH and AMSH-LP regulate receptor trafficking by specifically cleaving Lys 63-linked polyubiquitin chains from internalized receptors. Here we report the crystal structures of the human AMSH-LP DUB domain alone and in complex with a Lys 63-linked di-ubiquitin at 1.2 A and 1.6 A resolutions, respectively. The AMSH-LP DUB domain consists of a Zn(2+)-coordinating catalytic core and two characteristic insertions, Ins-1 and Ins-2. The distal ubiquitin interacts with Ins-1 and the core, whereas the proximal ubiquitin interacts with Ins-2 and the core. The core and Ins-1 form a catalytic groove that accommodates the Lys 63 side chain of the proximal ubiquitin and the isopeptide-linked carboxy-terminal tail of the distal ubiquitin. This is the first reported structure of a DUB in complex with an isopeptide-linked ubiquitin chain, which reveals the mechanism for Lys 63-linkage-specific deubiquitination by AMSH family members.     

一维物质结构的模拟及其衍射特性的考察

讨论几类一维准晶的结构、理论模型、有序度及其 Ｘ 射线衍射特性。     

草果精油成分鉴定及其抗菌活性研究

Clevenger法萃取草果获得草果精油,采用GC-MS分析检测出38个成分,通过保留指数解析出占总成分9714%的30个成分,主要成分为1,8-桉树脑（4089%) , α-水芹烯（977%) , 4-丙基苯甲醛（699%）等. 与匹配度对照解析法比较,有24个成分一致,占总成分的9281%. 用外标法定量分析了主要成分1,8-桉树脑含量,其质量分数为480%. 然后,研究了草果精油和1,8-桉树脑的抗菌活性. 结果显示,精油具有明显的抗菌活性,而1,8-桉树脑几乎无抗菌活性. 精油对细菌的抗菌活性由大到小依次是枯草芽孢杆菌、白葡萄球菌、大肠杆菌;对霉菌的抑菌活性由大到小依次是米曲霉菌、根霉、青霉.     

东莞市大气颗粒物中多环芳香烃的特征与来源研究

以PAHs的年度污染综合评价为基础,考察了东莞市虎门镇和松山湖地区大气颗粒物中PAHs浓度及季节变化特征;再利用文献报道的PAHs毒性指标,评价了健康影响的危害性;同时采用特定PAHs比值法,解析了东莞市大气颗粒中PAHs主要污染来源。     

Formation of indolyl-3-acetylaspartic acid in rats

Summary Indolyl-3-acetylaspartic acid (IAAsp) was detected in the urine of rats given indolyl-3-acetic acid (IAA) i.p. It was ascertained that the conversion of IAA into IAAsp could be carried out not only in plants but also in animals.     

The yak genome and adaptation to life at high altitude

Domestic yaks (Bos grunniens) provide meat and other necessities for Tibetans living at high altitude on the Qinghai-Tibetan Plateau and in adjacent regions. Comparison between yak and the closely related low-altitude cattle (Bos taurus) is informative in studying animal adaptation to high altitude. Here, we present the draft genome sequence of a female domestic yak generated using Illumina-based technology at 65-fold coverage. Genomic comparisons between yak and cattle identify an expansion in yak of gene families related to sensory perception and energy metabolism, as well as an enrichment of protein domains involved in sensing the extracellular environment and hypoxic stress. Positively selected and rapidly evolving genes in the yak lineage are also found to be significantly enriched in functional categories and pathways related to hypoxia and nutrition metabolism. These findings may have important implications for understanding adaptation to high altitude in other animal species and for hypoxia-related diseases in humans.     

Solution-processed silicon films and transistors

The use of solution processes-as opposed to conventional vacuum processes and vapour-phase deposition-for the fabrication of electronic devices has received considerable attention for a wide range of applications, with a view to reducing processing costs. In particular, the ability to print semiconductor devices using liquid-phase materials could prove essential for some envisaged applications, such as large-area flexible displays. Recent research in this area has largely been focused on organic semiconductors, some of which have mobilities comparable to that of amorphous silicon (a-Si); but issues of reliability remain. Solution processing of metal chalcogenide semiconductors to fabricate stable and high-performance transistors has also been reported. This class of materials is being explored as a possible substitute for silicon, given the complex and expensive manufacturing processes required to fabricate devices from the latter. However, if high-quality silicon films could be prepared by a solution process, this situation might change drastically. Here we demonstrate the solution processing of silicon thin-film transistors (TFTs) using a silane-based liquid precursor. Using this precursor, we have prepared polycrystalline silicon (poly-Si) films by both spin-coating and ink-jet printing, from which we fabricate TFTs with mobilities of 108 cm2 V(-1) s(-1) and 6.5 cm2 V(-1) s(-1), respectively. Although the processing conditions have yet to be optimized, these mobilities are already greater than those that have been achieved in solution-processed organic TFTs, and they exceed those of a-Si TFTs (< or = 1 cm2 V(-1) s(-1)).     

Rheological and functional impairments in cholesterol-loaded human erythrocytes

Summary Decreased deformability, slightly increased suspension viscosity and retarded oxygen egress were observed in cholesterol-loaded, human erythrocytes. These functional changes resulted from the decreased membrane fluidity induced by cholesterol.