对金融危机中卫星领域发展前景的分析

“如果这些投资项目不能获得资金，这些边际业务案例中的一些不能进行下去，我认为这将是件好事。我大体上是一个乐观主义者，我认为信贷市场将重归正常并完全起作用。”     

Isolation of a cytokinin gene, ZOG1, encoding zeatin O-glucosyltransferase from Phaseolus lunatus

University students who were skilled or less-skilled readers were compared on tests of auditory information processing and immediate serial recall of auditory and visual digits. Reading skill was defined by performance on a pseudoword reading task. The good readers exhibited typical modality effects with higher recall of auditory than visual items from the last 3 serial positions. On the terminal list item, the less-skilled readers showed a modality effect comparable with that of the skilled readers, but on other list items the modality effect reversed and a visual superiority was obtained. Results were discussed in terms of C. G. Penney's (1989) separate-streams model of short-term verbal memory.     

Identification of a calcium binding site in Staphylococcus hyicus lipase: generation of calcium-independent variants

OBJECTIVES: To evaluate the effectiveness and morbidity of salvage brachytherapy for locally recurrent or persistent prostate cancer after radiotherapy failure. METHODS: In this retrospective study, 49 patients of median age 73.3 years (range 52.9 to 86.9) with biopsy-proven localized prostate cancer underwent interactive transperineal fluoroscopic-guided and biplane ultrasound-guided brachytherapy with either iodine 125 or palladium 103 after prior radiotherapy failure. Post-treatment follow-up was conducted for a median of 64.1 months (range 26.6 to 96.8) and included clinical assessment of disease status, assays of serum prostate-specific antigen (PSA) levels, and documentation of treatment-related symptoms and complications. Determination of biochemical treatment failure was based on two successive rising PSA values above the post-treatment PSA nadir value. RESULTS: The actuarial rate of local prostate cancer control was 98% (95% confidence interval [CI] 94% to 99%). Actuarial disease-specific survival at 3 and 5 years was 89% (95% CI 73% to 96%) and 79% (95% CI 58% to 91%), respectively. At 3 and 5 years, actuarial biochemical disease-free survival was 48% (95% CI 32% to 63%) and 34% (95% CI 17% to 51%), respectively. Post-treatment PSA nadir was found to be a significant predictor of biochemical disease-free survival. Actuarial biochemical disease-free survival of patients who achieved a PSA nadir less than 0.5 ng/mL was 77% (95% CI 53% to 90%) and 56% (95% CI 25% to 78%) at 3 and 5 years, respectively. Of 49 patients, 23 (47%) achieved a post-treatment PSA nadir less than 0.5 ng/mL. The incidence of serious complications after salvage brachytherapy, such as incontinence and rectal complications, was lower than that reported after other types of salvage procedures. CONCLUSIONS: Interactive transperineal fluoroscopic-guided and biplane ultrasound-guided brachytherapy is a novel, potentially curative salvage modality for patients in whom prior radiotherapy failed. In a population of patients with poor prognosis, this modality was associated with a high rate of local prostate cancer control and a 34% actuarial rate of biochemical disease-free survival at 5 years. The incidence of major complications after salvage brachytherapy appears to be lower than that after other potentially curative salvage procedures, such as radical prostatectomy and cryoablation. Salvage brachytherapy warrants further investigation.     

Development of discrete nanopores. II. Comparison between layered films and blends of polyolefins

Discrete nanopores develop in the interfacial regions of polyolefin blends and layered films under tension. They originate from crazelike structures in the early development stage, which later undergo disruption processes with an increase in strain. The disruption processes appear to be triggered by the existence of adjacent ductile polyolefins and their micromechanical deformations. The degree of nanopore development significantly varies among blends and layered systems, depending on several material parameters, such as the interfacial strength. Discrete nanopores are observed more often in metallocene systems and blends than in Ziegler–Natta systems and layered films. Macroscopically, with the development of discrete nanopores, metallocene systems show higher strain to break and significant shear yielding under tension. The disruption mechanism can be used to prepare nanoporous materials or to improve the mechanical performances of polyolefins. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 708–718, 2005     

Recognition of analogous and homologous protein folds--assessment of prediction success and associated alignment accuracy using empirical substitution matrices

Fold recognition methods aim to use the information in the known protein structures (the targets) to identify that the sequence of a protein of unknown structure (the probe) will adopt a known fold. This paper highlights that the structural similarities sought by these methods can be divided into two types: remote homologues and analogues. Homologues are the result of divergent evolution and often share a common function. We define remote homologues as those that are not easily detectable by sequence comparison methods alone. Analogues do not have a common ancestor and generally do not have a common function. Several sets of empirical matrices for residue substitution, secondary structure conservation and residue accessibility conservation have previously been derived from aligned pairs of remote homologues and analogues (Russell et al., J. Mol. Biol., 1997, 269, 423-439). Here a method for fold recognition, FOLDFIT, is introduced that uses these matrices to match the sequences, secondary structures and residue accessibilities of the probe and target. The approach is evaluated on distinct datasets of analogous and remotely homologous folds. The accuracy of FOLDFIT with the different matrices on the two datasets is contrasted to results from another fold recognition method (THREADER) and to searches using mutation matrices in the absence of any structural information. FOLDFIT identifies at top rank 12 out of 18 remotely homologous folds and five out of nine analogous folds. The average alignment accuracies for residue and secondary structure equivalencing are much higher for homologous folds (residue approximately 42%, secondary structure approximately 78%) than for analogues folds (approximately 12%, approximately 47%). Sequence searches alone can be successful for several homologues in the testing sets but nearly always fail for the analogues. These results suggest that the recognition of analogous and remotely homologous folds should be assessed separately. This study has implications for the development and comparative evaluation of fold recognition algorithms.