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61.
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
62.
63.
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
64.
F Bispinck J Fischer R Lüllmann-Rauch MW Ziegenhagen 《Canadian Metallurgical Quarterly》1998,50(4-6):411-415
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
65.
W. Fischer 《Progress in Organic Coatings》1993,22(1-4):181-193
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
66.
B Rehberg R Rüschner M Fischer BJ Ebeling A Hoeft 《Canadian Metallurgical Quarterly》1998,33(7):425-429
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
67.
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
68.
D. E. Spahr K. Friedrich J. M. Schultz R. S. Bailey 《Journal of Materials Science》1990,25(10):4427-4439
Microstructure and fracture mechanical behaviour of injection-moulded, longer glass fibrereinforced polypropylene (Verton* aspect ratio 320) were studied as a function of fibre volume fraction and compared to that of shorter fibre-filled polypropylene (aspect ratio 70). Toughness was measured using instrumented notched lzod and falling weight impact tests, as well as compact tension specimens. It was found that the addition of longer fibres generally increased the toughness of the material, although more significant increases were seen in the impact tests than were seen in the compact tension test. For the latter results, a correlation between toughness improvement and microstructural details was performed on the basis of the microstructural efficiency concept, a semi-empirical approach of the formK
c,C = (a* +nR)K
c,M, where,K
c,C andK
c,M are the fracture toughnesses of the composite and the matrix, respectively,a* is a matrix stress correction factor,n is a scaling parameter andR is a fibre reinforcement effectiveness factor. The latter corrects for differences in the composite microstructures, and incorporates effective fibre orientation factors, layering of injection moulded parts, and fibre volumes in the different layers.Nomenclature
a
crack length
-
a
*
matrix toughness correction factor
-
A
cross-sectional area
-
B
thickness of the sample plaques
-
C
thickness of the composite core regions
-
E
peak
energy adsorbed up to the maximum force in the impact load-displacement curve
-
E
t
tensile modulus
-
F
max
maximum force in impact force-displacement curves
-
f
p
fibre orientation factor
-
f
pe
effective orientation factor
-
f
pe,C
effective orientation parameter, core region
-
f
pe, s
effective orientation parameter, surface region
-
F
critical load in the tensile test load-displacement curves
-
K
c
critical stress intensity factor/fracture toughness
-
K
L
fracture toughness of the composite materials
-
K
d
dynamic fracture toughness
-
K
L
fracture toughness of the matrix
-
L
test with crack parallel to the mould filling direction
-
M
microstructural efficiency factor
-
n
scaling parameter for reinforcement effectiveness factor (energy absorbtion ratio)
-
R
reinforcement effectiveness factor
-
S
thickness of the composite surface regions
- T
test with crack perpendicular to the mould filling direction
-
V
f
fibre volume fraction
-
V
m
matrix volume fraction (= 1 —V
f)
-
W
specimen width
-
W
f
fibre weight fraction
-
W
m
matrix weight fraction (= 1 —W
f)
-
X
n
number average fibre length
-
X
v
volume average fibre length
-
Y(a/ W)
polynomial correction for compact tension specimens
-
variable in effective orientation factor formula
-
variable in effective orientation factor formula
- B
strain to break
- c
density of the composite
- f
fibre density
- m
matrix density
- F
fracture strength
-
fibre angle with respect to a reference direction 相似文献
69.
Friedrich Otto 《Theory of Computing Systems》1987,20(1):253-260
WhenC is a concurrency relation on alphabet , then */=
C
is a free partially commutative monoid. Here we show that it is decidable in polynomial time whether or not there exists a finite canonical rewriting systemR on such that the congruences
R
*
generated byR and =
C
induced byC coincide. Further, in case such a systemR exists, one such system can be determined in polynomial time. 相似文献
70.
Emerging scanning technologies currently capture diverse data that includes geometrical and physical properties (i.e. normals, material and color). Yet, existing inspection computational methods do not satisfy industry demands. This paper proposes a new approach for inherently handling diverse data and utilizing the synergy between inspection technologies and digital processing methods. Two methods were developed: a Hierarchical Space Decomposition Model (HSDM), which sorts the sampled data, and a 3D Geometrical Bilateral Filter (3D GBF) that utilizes the diverse data. These methods provide efficient data reduction while preserving sharp features. The feasibility of this approach is demonstrated on the diverse data. 相似文献