Charging control using pulsed scanning electron microscopy

This paper describes a novel method to observe highly charging specimens at high-beam voltages without specimen preparation. It is found that the technique greatly reduces charging artifacts such as image shift, astigmatism, and defocussing without sacrificing image quality. Images obtained of uncoated specimens are found to be comparable to gold-coated specimens and without exhibiting charging effects. The technique also allows the study of charge distribution effects in specimen charging of which very little understanding exists, particularly as far as the spatial and time-dependent properties of charging are concerned.     

A novel low-cost RCD snubber for bifilar-wound motors

A low-cost inverter capable of operating bifilar-wound AC or brushless DC motors up to several kilowatts is proposed. It incorporates an innovative snubber circuit which allows smaller and cheaper components to be used relative to a conventional RCD snubber. The circuit has been tested and its full operation, design, and test results are presented in this paper     

Anti-atrial fibrillation effects of cyclovirobuxine-D and its electrophysiological mechanism studied on guinea pig atria

Cyclovirobuxine-D (CVB-D) was shown to produce significant and dose-dependent protective effects against atrial fibrillation induced by CaCl2-Ach in mice. On atrial fibrillation induced by aconitine, ouabain or adrenaline in isolated guinea pig atria, the effects of CVB-D were similar to those of amiodarone. CVB-D 0.3-100 mumol.L-1 was shown to depress the automaticity of the isolated guinea pig right atria. In isolated left atria, CVB-D 0.3 mumol.L-1 was found to inhibit the abnormal automaticity elicited by adrenaline, to prolong the duration of action potential and effective refractory period and to reduce excitability. At high concentration (30 mumol.L-1), CVB-D was also found to decrease the maximal velocity of depolarization (Vmax) and to elongate the conduction time of initiation. Amiodarone 0.3-30 mumol.L-1 was shown to closely resemble CVB-D in electrophysiology without effect on Vmax.     

Nuclear microscopy study of fish scales

Fish scales are useful to ichthyologists for purposes of classification, identification, age determination and history study. So far, all studies of fish scales, for whatsoever purposes, have relied on the use of optical or electron microscopes to study their form and structure. Employing the NUS nuclear microscope, we measured the concentrations of Sr, Zn, Fe, Mn, Ni, Cu, Cr, As, Se, Br and Pb in the scales of 17 fish species. The objective was to test the hypotheses that the trace elements in scales could be used for species differentiation, and that the fish scale could potentially be used as a monitor for the environment. Our preliminary results gave positive indications.     

Identification of p90, a prominent tyrosine-phosphorylated protein in fibroblast growth factor-stimulated cells, as 80K-H

Tyrosine phosphorylation of cellular proteins occurs rapidly upon treatment of fibroblasts with acidic or basic fibroblast growth factors (aFGF, bFGF), suggesting a role for protein phosphorylation in the FGF signaling pathway. Stimulation of Swiss 3T3 cells and MRC-5 fibroblasts with bFGF results in the tyrosine phosphorylation of several proteins, of which the most prominent has been designated as p90. The phosphorylation of p90 is observed within 30 s of treating the cells with FGF but not with other growth factors. Microsequencing of p90 resolved on two-dimensional polyacrylamide gel electrophoresis indicated an N-terminal amino acid sequence which corresponded to a protein previously named as 80K-H. Polyclonal antibodies raised against the predicted C terminus of 80K-H recognized p90 on all Western blots. p90 was found to bind specifically to GRB-2-glutathione S-transferase fusion protein and to be immunoreactive with 80K-H antibody. In addition, anti-phosphotyrosine antibodies immunoprecipitated 80K-H from cell lysates of FGF-stimulated but not from control fibroblasts. The biological function of 80K-H is yet unknown. However, from this study and a previous observation of the obligatory dependence of p90 phosphorylation on FGF receptor occupation, it appears that 80K-H is involved in FGF signaling.     

Polymerase chain reaction-single-strand conformation polymorphism analysis for the VHL gene in chemically induced kidney tumors of rats using intron-derived primers

In patients with insulin-dependent diabetes mellitus (IDDM), albuminuria reflects widespread vascular dysfunction. Albuminuria has been associated to defects of heparan sulfate proteoglycan (HSPG) within the extracellular matrix. Our hypothesis is that loss of HSPG in vascular walls reduces the HSPG-bound lipoprotein-lipase activity (LPLA), thereby causing elevated levels of plasma triglyceride (TG) seen in IDDM patients with albuminuria. The aim of the present study was to evaluate whether LPLA in muscle capillaries could be related to TG in IDDM patients with and without albuminuria. This is a cross-sectional study including ten healthy control subjects (group C), nine patients with IDDM and urinary albumin excretion rate (AER) of 30 mg/24 h or less (group D0) and 20 patients with IDDM and AER greater than 30 mg/24 h (group DA). Muscle LPLA, plasma TG, total cholesterol, high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), and very-low-density lipoprotein cholesterol (VLDL) were measured. Between groups no difference in total cholesterol, TG, VLDL, and LDL was found. In patients with albuminuria, LPLA was reduced compared to controls, however, the difference between the groups was not statistically significant [median (range)] 35.9 mU/g (20.4-103) versus 44.6 mU/g (28.2-57.2) and 40.9 mU/g (21.7-53.5) in group DA, C, and D0, respectively, p = 0.76. AER was not correlated to LPLA. An overall negative correlation between TG and LPLA was found; r = -0.33, p = 0.04, supported by an overall significant positive correlation between LPLA and HDL; r = 0.32, p = 0.045. We conclude that, in insulin-dependent diabetes mellitus, skeletal muscle lipoprotein-lipase activity is associated with plasma triglyceride, while an association between lipoprotein-lipase activity and urinary albumin excretion is questionable.     

Approaches to reduce the effects of OOV queries on indexed spoken audio

We present several novel approaches to the Out of Vocabulary (OOV) query problem for spoken audio: indexing based on syllable-like units called particles and query expansion according to acoustic confusability for a word index. We also examine linear and OOV-based combination of indexing schemes. We experiment on 75 h of broadcast news, comparing our techniques to a word index, a phoneme index and a phoneme index queried with phoneme sequences. Our results show that our approaches are superior to both a word index and a phoneme index for OOV words, and have comparable performance to the sequence of phonemes scheme. The particle system has worse performance than the acoustic query expansion scheme. The best system uses word queries for in-vocabulary words and a linear combination of the phoneme sequence scheme and acoustic query expansion for OOV words. Using the best possible weights for linear combination, this system improves the average precision from 0.35 for a word index to 0.40, a result only obtainable if the weights could be learnt on a development query set. The next best system used a word index for in-vocabulary words and the phoneme sequence system otherwise and had average precision of 0.39.