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31.
BACKGROUND AND STUDY AIMS: It has recently been reported that in developed countries gastric outlet obstruction now predicts gastric malignancy. The aim of this study was to find out if this is the case in a developing country like India. PATIENTS AND METHODS: Seventy-four patients with gastric outlet obstruction underwent upper gastrointestinal endoscopy and biopsy specimens were obtained from any suspicious looking lesions or from the most distal point at which the endoscope could be positioned. RESULTS: In 56 patients (76%) the cause of the gastric outlet obstruction was malignant. On clinical and endoscopic appearance three patients were wrongly diagnosed as having malignancy when the cause, on endoscopic biopsy, was benign (tuberculosis n = 2, and immunoproliferative small intestinal disease n = 1). Twelve of the 18 patients with benign gastric outlet obstruction were managed conservatively with drugs and endoscopic balloon dilatation. CONCLUSION: Even in a developing country like India, malignancy is the commonest cause of gastric outlet obstruction and endoscopic biopsy specimens should be obtained in all patients with gastric outlet obstruction because the occasional benign lesions can be managed conservatively.  相似文献   
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33.
The influence of extra-cellular polymeric substances in microbiologically influenced corrosion Unexpected pitting failures in copper potable water installations have occurred in some countries (Germany, Sweden, Scotland, South-West England, Saudi-Arabia) in the mid-eighties. These failures could not be expected in a single case based on the chemical composition of the potable water. Further typical manifestation characteristics of this microbiologically influenced corrosion have been i.) an uptake of dissolved and undissolved copper species in an obsolete, non regular fashion, ii.) black layers of copper(II)-oxide on the inner tube surface, accompanied by posniakite and malachite in the pitting areas, and, iii.) the detection of extracellular polymeric substances (EPS). These EPS consist partly of polysaccharides. They could either be produced by microorganisms within the potable water installation or be transported in a dissolved or undissolved state into the installation. Consequently, they sediment on the inner surfaces of the copper tubes. The physico-chemical properties of some kinds of EPS, especially their membrane properties and their cation selectivity, play a key role in this corrosion process. This is shown exemplarily performing diffusion potential measurements and contact corrosion experiments.  相似文献   
34.
Dicationic amphiphilic drugs such as the immunomodulator tilorone [2,7-bis-[2-(diethylamino)ethoxy]fluoren-9-one] are accumulated in lysosomes and disturb the degradation of sulphated glycosaminoglycans (GAGs) thus leading to generalized lysosomal GAG storage (mainly dermatan sulphate) in vivo and in cultured cells. In the present study, the time course of the tilorone-induced GAG storage was determined in cultured bovine corneal fibroblasts by a radiochemical approach and by morphological examination. In contrast to the rapid lysosomal accumulation of the drug as reported previously, it took approximately 42 h to reach 50% of the GAG storage obtained after 96 h. This is thought to be due to the fact that the temporal development of storage of undigested GAGs depends on the natural delivery of GAGs towards the lysosomal apparatus.  相似文献   
35.
Corrosion protection of organic coated steel is determined by free corrosion potential measurements and impedance spectroscopy. The results are classified by means of very basic considerations and evaluation figures are developed. These electrochemical data are correlated with the extent of the corrosion for each coating system. The evaluation figures are used for ranking coating systems and this ranking is correlated with the ranking with reference to the results of standardized and exposure tests.  相似文献   
36.
Despite improvement in early diagnosis, surgical techniques, and general patient care, most deaths of cancer patients result from metastases. Recent studies have revealed that cytokines produced by cancer cells or by stromal cells play an important role into development the cancer metastasis. The formation of a cancer metastasis involves several major steps: 1) extensive vascularization; 2) local invasion; 3) adherence either to capillary endothelial cells or to subendothelial basement membrane; 4) extravasation; and 5) proliferation. In colon cancer, several cytokines such as growth factors, inflammatory cytokines, and angiogenic factors have been confirmed to be involved in each step of metastasis. This paper summarizes the involvement of cytokines in the development of invasion and metastasis in colon cancer.  相似文献   
37.
A lattice-based vector quantizer (VQ) and noiseless code are proposed for transform and subband image coding. The quantization is simple to implement, and no vector codebooks need to be stored. The noiseless code enumerates lattice codevectors based on their (weighted) l(1) norm. A software implementation is able to handle lattice codebooks of size 2(256). The image coding performance is shown to be comparable or superior to the best encoding methods reported in the literature.  相似文献   
38.
The concept of smoothing noisy data using appropriate polynomials turns out to be equivalent to the application of suitable nonrecursive digital filters having the following properties: They process the data in such a way that the moments are conserved up to a desired order while the energy of their impulse response is minimum. Flatness constraints of their frequency response at =0 are equivalent to the moment condition. By using orthogonal polynomials, an explicit solution is known from the literature. A second approach which uses a special decomposition also yields closed form solutions. The realization is simplified, especially in the case where a large number of moments is supposed to be conserved.  相似文献   
39.
We report the characterization of amphiphilic aminoglycoside conjugates containing luminophores with aggregation-induced emission properties as transfection reagents. These inherently luminescent transfection vectors are capable of binding plasmid DNA through electrostatic interactions; this binding results in an emission “on” signal due to restriction of intramolecular motion of the luminophore core. The luminescent cationic amphiphiles effectively transferred plasmid DNA into mammalian cells (HeLa, HEK 293T), as proven by expression of a red fluorescent protein marker. The morphologies of the aggregates were investigated by microscopy as well as ζ-potential and dynamic light-scattering measurements. The transfection efficiencies using luminescent cationic amphiphiles were similar to that of the gold-standard transfection reagent Lipofectamine® 2000.  相似文献   
40.
In this paper, a novel concept of a thermo-mechanical MEMS actuator using aluminum thin-film heaters on a thermal oxide for electrical insulation is presented. The actuator is part of an universal tensile testing platform for thermo-mechanical material characterization of one dimensional materials on a micro- and nano-scopic scale under different environmental conditions, as varying temperatures, pressure, moisture or even vacuum and is realised in BDRIE technology. It is shown, that the actuator concept fulfills the requirements for the use in a tensile loading stage along with heterogeneously integrated nanofunctional elements, following a specimen centered approach in line with bottom-up self-assembly processes. Simulation and experiment agree very well in the thermal and mechanical domain and allow subsequent optimisation of the actuator performance.  相似文献   
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