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1.
Families in transition (FIT), a joint program between Beth Israel Medical Center (BIMC) and National Development and Research Institutes, Inc., uses indigenous neighborhood women, Compa?eras (companions), to conduct street outreach in a New York City neighborhood where HIV infection is rampant. The outreach workers inform people that, not only will they be assisted in talking about HIV and guardianship for their children, but that they will be provided information concerning access to food stamps, housing, health care, and other basic needs. Through community participation, the Compa?eras empower themselves through knowledge making and sharing and, in the process, create conditions in which other women can began to effect changes in their individual lives and families. The ultimate goal of the project is to support HIV-infected women in finding their voices so that they can talk with their children and plan for their futures. 相似文献
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Double exposure holographic interferometry (DEHI) is used to determine the strain energy release rate, craze opening displacement profile, and craze stress profile ofn-heptane and methanol crazes growing from cracks in polystyrene.n-heptane crazes have strain energy release rates (SERRs) close to those of cracks and their stress profile is almost crack-like in that the tensile stress across the craze falls almost to zero. On the other hand, the SERRs of methanol crazes are only 30 to 55% the SERR of a crack depending on stress intensity factorK
I of the precrack from which they are grown. The stress profile of the methanol craze shows it to be strongly load-bearing away from the craze tip, apparently as a result of the strain hardening of the craze fibrils. The stress concentration in front of the methanol craze tip is only 40% of that in front of then-heptane craze tip. The opening displacements of the methanol craze are almost as large as those of a crack very near its tip but are much less than those of a crack at large distances behind the tip. The Dugdale model of a strip yielding zone provides a poor representation of the craze opening displacements of the growing methanol craze. Dry (static) methanol crazes have larger opening displacements in response to an incremental tensile strain at moderate prestrains than at either low or high prestrains, suggesting that the craze fibrils undergo a yielding/strain-hardening process as the strain is increased similar to that observed in polycarbonate crazes by Kopp and Kambour. Dryn-heptane crazes do not show this response but rather open linearly with increasing prestrain. The opening displacement for long (dry)n-heptane crazes is almost crack-like whereas the largest opening of a dry methanol craze is only 20% of that of a crack. Dry methanol crazes break at aK
IC that is 40% of theK
IC of precracked but uncrazed specimens. The strongest (shortest) dryn-heptane crazes fail at only 7% ofK
IC of uncrazed specimens and theK
IC of the dryn-heptane crazes decreases markedly with increasing craze length. 相似文献
5.
Ekman Paul; Friesen Wallace V.; O'Sullivan Maureen; Chan Anthony; Diacoyanni-Tarlatzis Irene; Heider Karl; Krause Rainer; LeCompte William Ayhan; Pitcairn Tom; Ricci-Bitti Pio E.; Scherer Klaus; Tomita Masatoshi; Tzavaras Athanase 《Canadian Metallurgical Quarterly》1987,53(4):712
We present here new evidence of cross-cultural agreement in the judgment of facial expression. Subjects in 10 cultures performed a more complex judgment task than has been used in previous cross-cultural studies. Instead of limiting the subjects to selecting only one emotion term for each expression, this task allowed them to indicate that multiple emotions were evident and the intensity of each emotion. Agreement was very high across cultures about which emotion was the most intense. The 10 cultures also agreed about the second most intense emotion signaled by an expression and about the relative intensity among expressions of the same emotion. However, cultural differences were found in judgments of the absolute level of emotional intensity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
The use of phospholipid vesicles as reaction containers, as vehicles for pharmaceutical drug delivery, and as model systems for cells has prompted the development of new methods for analyzing the structure of vesicles and their contents. The pH of the interior of vesicles is of particular interest when analytes are encapsulated and concentrated with the use of a pH gradient. While the interior pH is generally measured for large populations of vesicles, we report the measurement of the interior pH of individual vesicles as their buffer contents are titrated by transfer of N-methylbutylamine (NMBA) into the vesicle by a pH gradient. The initially acidic buffer within the vesicles is titrated along with a small concentration of an encapsulated pH sensitive dye, 5,6-carboxy SNARF-1-dextran. Images of the indicator fluorescence from each vesicle and its dispersed fluorescence spectrum are recorded using epi-illumination spectral fluorescence microscopy. From a fit of the spectra to the respective acid and base forms of the fluorescent indicator, the interior pH of individual vesicles as a function of the concentration of the NMBA titrant in the external solution could be determined. 相似文献
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BACKGROUND: Invasive growth of epithelial tumor cells, a major cause of death from cancer in humans, involves loss of epithelial polarity and dedifferentiation. Transforming growth factor beta (TGFbeta) is regarded as a major tumor suppressor during early tumor development because it inhibits cell-cycle progression and tumor growth. Many dedifferentiated, late-stage tumors are resistant to growth inhibition by TGFbeta, however, and even secrete TGFbeta. In line with this, TGFbeta is involved in angiogenesis, wound healing and epithelial-mesenchymal transition (EMT) during development. Ha-Ras-transformed mammary epithelial cells (EpRas) undergo TGFbeta-induced EMT maintained via a TGFbeta autocrine loop. Thus, we have analyzed whether signal transduction by the TGFbeta receptor (TGFbetaR) is required for local tumor cell invasion and metastasis. RESULTS: A dominant-negative type II TGFbetaR (TGFbetaRII-dn) was expressed using retroviral vectors in EpRas cells and highly metastatic mesenchymal mouse colon carcinoma cells (CT26). In both cell types, TGFbetaRII-dn blocked TGFbetaR signaling and heavily delayed tumor formation. In EpRas cells, TGFbetaRII-dn prevented EMT. In the dedifferentiated mesenchymal CT26 cells, TGFbetaRII-dn caused mesenchymal-to-epithelial transition and inhibited their in vitro invasiveness in several assays. In addition, TGFbetaRII-dn completely abolished metastasis formation by CT26 cells. Furthermore, several human carcinoma lines lost in vitro invasiveness when treated with neutralizing TGFbeta antibodies or soluble receptor variants. Finally, human colon carcinoma cells (hnPCC) expressing a mutated, non-functional TGFbetaRII were non-invasive in vitro, a defect restored by re-expressing wild-type TGFbetaRII. CONCLUSIONS: Cell-autonomous TGFbeta signaling is required for both induction and maintenance of in vitro invasiveness and metastasis during late-stage tumorigenesis. TGFbetaRII therefore represents a potential target for therapeutical intervention in human tumorigenesis. 相似文献
8.
OBJECTIVE: To describe our experience with primary appendiceal tumours. DESIGN: Retrospective study. SETTING: University hospital, Israel. SUBJECTS: 2520 patients who had appendectomies during the 14 years, January 1982-December 1996. RESULTS: 22 patients 5 male and 17 female, mean age 56.2 years, had primary neoplasms; 14 were carcinoid tumours and villous adenomas and were treated by appendicectomy only. Adenocarcinoma was diagnosed in 8 patients (0.3%), 5 after appendicectomy (0.2%) which is twice the reported incidence. They were all treated by right hemicolectomy. Seven of the patients were classified as Dukes' B and one as Dukes' C. All patients were alive and disease-free after a mean follow-up period of 57.4 months. CONCLUSION: Right hemicolectomy is the treatment of choice for adenocarcinoma of the appendix. 相似文献
9.
The structure of crazes grown in polystyrene (PS) immersed inn-heptane and methanol at room temperature has been determined using refractive index measurements, transmission electron microscopy, and fractographic analysis of craze fracture surfaces.n-heptane crazes in thin films exhibit a low number density of thick, load-bearing fibrils whereas methanol crazes consist of a highly interconnected network of fibrils not unlike the craze structure found in crazes grown in air. A row of large voids at the centre line of the craze which is typical of the structure observed in air crazes is not found, however, in either methanol orn-heptane crazes, indicating a different growth mechanism for the solvent crazes. The craze structure found in thin films is in agreement with the void contents determined from refractive index measurements and with the results from scanning electron microscopy of fracture surfaces of bulk crazes grown with methanol andn-heptane. Glass transition temperature measurements of equilibrium swollen PS films giveT
g=91° C for methanol andT
g=6° C forn-heptane. The results suggest that the structure of crazes grown with slowly diffusing crazing agents (methanol andn-heptane) is strongly dependent on whether the growth temperature is above or belowT
g, the glass transition temperature of the plasticized region just ahead of, and in, the craze. IfT
g is below the growth temperature, weak crazes are formed with a large void content. During the growth, thin fibrils break by viscous flow leaving only a small number of load-bearing fibrils. The stress in the neighbourhood of the growing craze is strongly relieved favouring propagation of a single craze. IfT
g is above the growth te'mperature, strong crazes are formed with the fibrils strain-hardened during the growth process. There is hardly any change in stress next to the craze and therefore multiple crazing (craze bundles) is favoured over the propagation of a single craze. 相似文献
10.
B. Markicevic A. Nalla H.K. Navaz D. Heider S. Walsh S.G. Advani 《Polymer Composites》2010,31(8):1434-1441
The resin flow from multiple line injection into a fibrous porous medium is investigated analytically and experimentally. The flow in a rectangular porous medium is created by placing two inlets: a channel along one of the domain edges, and a manifold placed in the center of the domain perpendicular to the first inlet on the top surface of the porous medium. It is demonstrated that two distinct sub‐regions of the porous medium exist: inner sub‐region which is filled by the liquid from the manifold, and outer sub‐region that is filled by fluid from the channel. In the experiments, the following geometric parameters are varied: channel cross‐sectional area, mold width, and thickness to investigate how the processing parameters influence which part of the overall domain is filled by fluid from a specific inlet. Neither fluid nor porous medium are varied throughout the study. For nonconstrained flow, an analytical model is formulated to predict the interface between the two sub‐regions which is called the inner sub‐region thickness. Both, implicit and explicit solutions are found, where the explicit solution is represented as inverse Lambert function. The solution relies on one physical constant which is a function of the pressure gradients and the directional permeabilities of the fibrous preform. Comparisons between experimental and analytical results reveal an excellent agreement for various sets of geometric parameters. This research should prove useful in understanding the flow in composites manufacturing when resin is injected simultaneously from multiple gates and channels. POLYM. COMPOS., 31:1434–1441, 2010. © 2009 Society of Plastics Engineers 相似文献