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101.
Compression creep tests were performed on the ternary 91.84Sn-3.33Ag-4.83Bi (wt.%, abbreviated Sn-Ag-Bi) Pb-free alloy. The test temperatures were: −25 °C, 25 °C, 75 °C, 125 °C, and 160 °C (± 0.5 °C). Four loads were used at the two lowest temperatures and five at the higher temperatures. The specimens were tested in the as-fabricated condition or after having been subjected to one of two air aging conditions: 24 hours at either 125 °C or 150 °C. The strain-time curves exhibited frequent occurrences of negative creep and small-scale fluctuations, particularly at the slower strain rates, that were indicative of dynamic recrystallization (DRX) activity. The source of tertiary creep behavior at faster strain rates was likely to also be DRX rather than a damage accumulation mechanism. Overall, the strain-time curves did not display a consistent trend that could be directly attributed to the aging condition. The sinh law equation satisfactorily represented the minimum strain rate as a function of stress and temperature so as to investigate the deformation rate kinetics: dε/dtmin = Asinhn (ασ) exp (−ΔH/RT). The values of α, n, and ΔH were in the following ranges (±95% confidence interval): α, 0.010–0.015 (±0.005 1/MPa); n, 2.2–3.1 (±0.5); and ΔH, 54–66 (±8 kJ/mol). The rate kinetics analysis indicated that short-circuit diffusion was a contributing mechanism to dislocation motion during creep. The rate kinetics analysis also determined that a minimum creep rate trend could not be developed between the as-fabricated versus aged conditions. This study showed that the elevated temperature aging treatments introduced multiple changes to the Sn-Ag-Bi microstructure that did not result in a simple loss (“softening”) of its mechanical strength. 相似文献
102.
Janice L. Y. Mong Maggie C. Y. Ng Georgia S. Guldan Claudia H. T. Tam Heung Man Lee Ronald C. W. Ma Wing Yee So Gary W. K. Wong Alice P. S. Kong Juliana C. N. Chan Mary M. Y. Waye 《Clinical endocrinology》2010,73(3):313-322
Objective: To explore the genetic effect of the GH receptor (GHR) on obesity and related metabolic parameters in Hong Kong Chinese adolescents. Context: Obesity is a growing global epidemic. Increasing evidence suggests that the GH‐IGF‐I axis plays an important role in regulating adiposity and insulin sensitivity. Design: We examined the associations of genetic variants of GHR with serum IGF‐I and IGFBP‐3 levels as well as obesity‐related metabolic traits in Hong Kong Chinese adolescents. Patients: Nine hundred and eighty‐one randomly selected Hong Kong Chinese adolescents from 14 schools. Measurements: We genotyped 17 single nucleotide polymorphisms (SNP) at GHR and measured serum IGF‐I and IGFBP‐3 levels as well as obesity‐related metabolic traits including fasting plasma glucose, insulin and lipid levels. Results: There were significant associations between rs4410646 and the body composition (P = 0·0044) and blood pressure factor scores (P = 0·00017). Carriers of the CC genotype had lower body mass index, percentage body fat, waist and hip circumferences than AC and AA genotype carriers (P = 0·00030–0·0094). There was also association between rs7703713 and the IGF‐I activity factor score (P = 0·0033). The GA and AA carriers of rs7703713 had higher serum IGF‐I, higher serum IGFBP‐3 and higher IGF‐I/IGFBP‐3 molar ratio (P = 0·00069–0·025). Haplotype analysis did not increase the significance of associations. Conclusion: Our results support the role of GHR gene polymorphisms in modulating adiposity and IGF‐I activity in adolescents. Examination of interactions of these SNPs with lifestyle, environmental and perinatal factors may provide further insights into their long‐term effects on obesity and metabolic risks. 相似文献
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Type 1 and type 2 cytokine-producing CD4+ and CD8+ T cells in primary antiphospholipid syndrome 总被引:1,自引:0,他引:1
Karakantza M Theodorou GL Meimaris N Mouzaki A John E Andonopoulos AP Maniatis A 《Annals of hematology》2004,83(11):704-711
Antiphospholipid syndrome (APS) is an autoimmune condition characterized by thrombosis and/or recurrent fetal loss as well as the presence of autoantibodies against epitopes present on phospholipid-binding proteins. The role of cellular immunity in the pathogenesis of the syndrome remains unclear. We studied the cellular phenotype and the production of type 1 [interferon (IFN)-, interleukin (IL)-2] and type 2 (IL-4, IL-10) cytokines by CD4+ and CD8+ T-lymphocyte subsets in 13 patients with untreated primary APS (PAPS) and in 32 healthy controls. The production of cytokines was determined in T cells after a 5-h culture with or without mitogenic stimulation using a flow cytometric method of intracellular cytokine staining. In six of the patients these studies were repeated 6 months later. In PAPS patients we found a reduced percentage of circulating CD4+CD45RA+ and an increased percentage and absolute number of CD8+HLA-DR+ cells. A type 1 response was observed in the patients unstimulated cells, indicated by an increase in IFN--producing CD8+, IL-2-producing CD4+ T cells, and a decrease in IL-4-producing CD4+ and CD8+ T cells. Similar results were obtained in the patients at follow-up. Taken together, these results suggest a chronic in vivo stimulation of CD4+ and CD8+ T cells in PAPS patients exhibiting a type 1 polarization. Changes of cellular immunity may contribute to the pathogenesis of the clinical manifestations of the syndrome and might be proven to be useful targets for therapeutic interventions in the future. 相似文献
105.
Lacativa PG Donangelo I Wagman MB Sieiro Neto L Caldas CR Violante AH Lima RJ Vaisman M 《Arquivos brasileiros de endocrinologia e metabologia》2004,48(2):318-323
Opportunistic infections in endogenous Cushing's syndrome are associated with severe cortisol excess and carry a high mortality. Pulmonary cryptococcosis is one of these opportunistic infections and can mimic a lung neoplasm, therefore making its diagnosis difficult. We report a case of a young male with ACTH-dependent Cushing's syndrome and severe hypercortisolism. The patient achieved cure after the transfenoidal surgery, but developed a febrile state. A chest computed tomography showed a pulmonary nodule that did not change in serial chest radiographs. Diagnosis of tuberculosis, fungal and bacterial infections were inconclusive, so the hypothesis of lung neoplasm became more probable. The necropsy, however, disclosed a pseudotumoral cryptococcosis. Opportunistic infections, like Cryptococcus neoformans, should be considered in patients with Cushing's syndrome and a pulmonary infiltrate. 相似文献
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Sidney C Smith Ted E Feldman John W Hirshfeld Alice K Jacobs Morton J Kern Spencer B King Douglass A Morrison William W O'Neill Hartzell V Schaff Patrick L Whitlow David O Williams Elliott M Antman Sidney C Smith Cynthia D Adams Jeffrey L Anderson David P Faxon Valentin Fuster Jonathan L Halperin Loren F Hiratzka Sharon Ann Hunt Alice K Jacobs Rick Nishimura Joseph P Ornato Richard L Page Barbara Riegel 《Journal of the American College of Cardiology》2006,47(1):e1-121
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Stacy Schantz Wilkins PhD Rebecca J. Melrose PhD Katherine S. Hall PhD Erin Blanchard MS Steven C. Castle MD Teresa Kopp PT MBA Leslie I. Katzel MD PhD Alice Holder MHS PT Neil Alexander MD Michelle K.S. McDonald BA OT Arti Tayade MD CMD HMDC Daniel E. Forman MD Lauren M. Abbate MD PhD Rebekah Harris PT DPT PhDc Willy M. Valencia MD Miriam C. Morey PhD Cathy C. Lee MD 《Journal of the American Geriatrics Society》2021,69(4):1045-1050