Advanced components and sub-system solutions for 40 Gb/s transmission

With the commissioning of the latest 10-Gb/s systems, vendors are now in the process of developing architectures for their next-generation products. 40-Gb/s components and subsystems are currently in development to address the necessities of these next-generation systems. The top three challenges associated with 40-Gb/s transmission are optical signal-to-noise ratio, dispersion, and high-speed components. In order to realize 40-Gb/s transmission, new component and subsystem developments are crucial. This paper reviews the latest transmission technologies and dispersion compensation techniques developed to fulfill 40-Gb/s transmission system requirements.     

硫酸铁催化合成乙酸乙酯工艺研究

以硫酸铁为催化剂，合成乙酸乙酯，探讨影响酯化反应的各种因素，在最佳反应条件催化剂占物料总量6．5％，酸醇比为1：1．5，反应时间为30min时，乙酸的转化率可达98．1％，精酯收率达93．5％。     

Digital geological mapping with tablet PC and PDA: A comparison

Both the hardware and software available for digital geological mapping (DGM) have advanced considerably in recent years. Mobile computers have become cheaper, lighter, faster and more power efficient. Global Positioning Systems (GPS) have become cheaper, smaller and more accurate, and software specifically designed for geological mapping has become available. These advances have now reached a stage where it is effective to replace traditional paper-based mapping techniques with those employing DGM methodologies. This paper attempts to assess and evaluate two currently available DGM systems for geological outcrop mapping: one based on a Personal Digital Assistant (PDA) running ESRI “ArcPad”, and the second based on a Tablet PC running “Map IT” software. Evaluation was based on field assessment during mapping of a well-exposed coastal section of deformed Carboniferous and Permian rocks at N. Tynemouth in NE England. Prior to the field assessment, several key criteria were identified as essential attributes of an effective DGM system. These criteria were used as the basis for the assessment and evaluation process. Our findings suggest that the main concerns presented by sceptics opposed to DGM have largely been resolved.In general, DGM systems using a Tablet PC were found to be most suitable for a wide range of geological data collection tasks, including detailed outcrop mapping. In contrast, systems based on a PDA, due to small screen and limited processing power, were best suited for more basic mapping and simple data collection tasks. In addition, PDA-based systems can be particularly advantageous for mapping projects in remote regions, in situations where there is a limited power supply or where total weight of equipment is an important consideration.     

Fish mapping of YAC clones at human chromosomal band 7q31.2: identification of YACS spanning FRA7G within the common region of LOH in breast and prostate cancer

OBJECTIVES: The value of serum Ca 19-9 dosage for pancreatic carcinoma diagnosis has been studied in heterogeneous series. The effect of the complications of chronic pancreatitis and pancreatic carcinoma on serum Ca 19-9 value has not been assessed precisely. The aims of this study were to assess: a) the value of Ca 19-9 to differentiate benign from malignant pancreatic disease; b) the influence of complications (particularly, cholestasis). METHODS: The studied population included 179 patients: 126 with chronic pancreatitis (25 females, 101 males, 45 with cholestasis) and 53 with pancreatic carcinoma (27 females, 26 males, 37 with cholestasis). RESULTS: At 37 UI/mL threshold, the specificity and sensitivity of Ca 19-9 were 53 and 95%, respectively. Cholestasis was associated with a significant increase of Ca 19-9 in patients with chronic pancreatitis but not in those with pancreatic carcinoma. At 300 UI/mL threshold, the specificity and sensitivity of Ca 19-9 were 95 and 81% in patients without cholestasis and 87 and 81% in those with cholestasis, respectively. Diabetes mellitus was associated with a significant increase of Ca 19-9 only in patients with chronic pancreatitis without cholestasis. Pancreatic calcifications, pseudocysts, cirrhosis, pleural effusion or ascites were not associated with significant variation of Ca 19-9. CONCLUSION: In patients with pancreatic disease, 300 UI/mL threshold is the most accurate to differentiate benign from malignant disease, whatever the presence of cholestasis.     

Cognitive rehabilitation: how it is and how it might be

This paper suggests there are, at present, four main kinds of cognitive rehabilitation programs for brain injured people. The first attempts to rehabilitate cognitive deficits through drills and exercises. The second uses theoretical models from cognitive psychology to identify deficits in order to remediate them. The third is primarily a patient-driven approach that uses a combination of learning theory, cognitive psychology, and neuropsychology to identify and remediate cognitive difficulties. The fourth is the holistic approach that has, as its basic philosophy, a belief that cognitive functions cannot be divorced from emotion, motivation, or other noncognitive functions, and consequently all aspects of functioning should be addressed in rehabilitation programs. Despite some overlap between these approaches, there are major differences. The two main arguments offered in this paper are (1) that the first two approaches do not lead to good clinical rehabilitation practice; and (2) that a synthesis of the second two approaches would result in the best cognitive rehabilitation model.     

Lentiviral vectors for gene therapy of cystic fibrosis

A replication-defective vector based on human immunodeficiency virus (HIV) was evaluated for gene transfer directed to the lung. The tropism of this vector has been expanded through the incorporation of the vesticular stomatitis virus G protein into its envelope. The HIV vector effectively transduced nondividing airway epithelial cells in vitro whereas a murine-based retroviral vector did not. Experiments in a human bronchial xenograft model demonstrated high-level gene transduction with a cystic fibrosis transmembrane conductance regulator (CFTR) HIV vector into undifferentiated, cystic fibrosis (CF)-derived cells of the xenograft. CFTR expression was stable and capable of functional correction of the CF defect after the graft matured. The HIV vector did not effectively transduce cells of the xenograft when instilled after the epithelium had differentiated. This block to transduction appears to be at the level of entry, although post entry restrictions cannot be ruled out. Further development of this vector system for CF gene therapy should focus on a better understanding of potential entry and post entry blocks.     

Proprioceptive Perception of Phase Variability.

Previous work has established that judgments of relative phase variability of 2 visually presented oscillators covary with mean relative phase. Ninety degrees is judged to be more variable than 0° or 180°, independently of the actual level of phase variability. Judged levels of variability also increase at 180°. This pattern of judgments matches the pattern of movement coordination results. Here, participants judged the phase variability of their own finger movements, which they generated by actively tracking a manipulandum moving at 0°, 90°, or 180°, and with 1 of 4 levels of Phase Variability. Judgments covaried as an inverted U-shaped function of mean relative phase. With an increase in frequency, 180° was judged more variable whereas 0° was not. Higher frequency also reduced discrimination of the levels of Phase Variability. This matching of the proprioceptive and visual results, and of both to movement results, supports the hypothesized role of online perception in the coupling of limb movements. Differences in the 2 cases are discussed as due primarily to the different sensitivities of the systems to the information. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Phenomenological study and modelling of wick debinding

Wick debinding employs capillary suction (via a surrounding wicking powder) to remove the liquid binder phase from powder injection moulded parts (known as a compact). Experimental measurements of binder distribution within the compact during debinding highlight flaws in previous wick debinding models. The spatially uniform distribution of binder observed consistently during debinding indicates that it is removed in order of pore size regardless of location in the compact. A model is proposed which gives good agreement with 1-D experimental data of binder distribution. Key parameters of the model are the permeability of the wicking powder and the relationship between the capillary pressure, saturation and relative permeability of the compact.