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排序方式: 共有185条查询结果,搜索用时 9 毫秒
1.
The aim of this study was to determine the effect of a short-term ethinyl estradiol/levonorgestrel medication on blood flow in the uterine arteries in postmenopausal women in a prospective placebo-controlled double-blind study. Twenty-one healthy postmenopausal woman at least 2 years after menopause received 60 micrograms ethinyl estradiol (EE) for 14 days followed by 40 micrograms EE plus 125 micrograms levonorgestrel (LNG) for 12 days (total treatment period 26 days). Sonographically, uterine volume, endometrial thickness, and blood flow in the uterine arteries [as reflected by pulsatility (PI) and resistance indices (RI)] were measured. Uterine size increased from 44 to 80 mL (day 14, p < 0.001) and 87 mL (day 26, p = NS). Endometrium grew from 3 to 8 mm (day 14, p < 0.001) and 11 mm (day 26, p = NS). Uterine arterial PI fell from 2.76 to 1.37 (day 14, p < 0.001) and 1.34 (day 26, p = NS), whereas RI fell from 0.9 to 0.68 (day 14 and day 26, p < 0.001). In conclusion, short-term treatment with LNG does not antagonize the vascular effect of EE on the uterine arteries as reflected by PI and RI. This result might have clinical significance in the selection of the progestin used in hormonal replacement therapy. 相似文献
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Mun Fai Loke Indresh Yadav Teck Kwang Lim Johan R. C. van der Maarel Lok-To Sham Vincent T. Chow 《International journal of molecular sciences》2022,23(6)
The presence of co-infections or superinfections with bacterial pathogens in COVID-19 patients is associated with poor outcomes, including increased morbidity and mortality. We hypothesized that SARS-CoV-2 and its components interact with the biofilms generated by commensal bacteria, which may contribute to co-infections. This study employed crystal violet staining and particle-tracking microrheology to characterize the formation of biofilms by Streptococcus pneumoniae and Staphylococcus aureus that commonly cause secondary bacterial pneumonia. Microrheology analyses suggested that these biofilms were inhomogeneous soft solids, consistent with their dynamic characteristics. Biofilm formation by both bacteria was significantly inhibited by co-incubation with recombinant SARS-CoV-2 spike S1 subunit and both S1 + S2 subunits, but not with S2 extracellular domain nor nucleocapsid protein. Addition of spike S1 and S2 antibodies to spike protein could partially restore bacterial biofilm production. Furthermore, biofilm formation in vitro was also compromised by live murine hepatitis virus, a related beta-coronavirus. Supporting data from LC-MS-based proteomics of spike–biofilm interactions revealed differential expression of proteins involved in quorum sensing and biofilm maturation, such as the AI-2E family transporter and LuxS, a key enzyme for AI-2 biosynthesis. Our findings suggest that these opportunistic pathogens may egress from biofilms to resume a more virulent planktonic lifestyle during coronavirus infections. The dispersion of pathogens from biofilms may culminate in potentially severe secondary infections with poor prognosis. Further detailed investigations are warranted to establish bacterial biofilms as risk factors for secondary pneumonia in COVID-19 patients. 相似文献
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Developing Structural Integrated Stressor–Stress Models for Clients’ and Contractors’ Cost Engineers
Mei-yung Leung Yee-shan Chan Alice Chong Janet Fung-Chu Sham 《Canadian Metallurgical Quarterly》2008,134(8):635-643
Estimation is not a purely scientific task. It requires cost engineers equipped with a wide knowledge of construction and a professional ability to make judgments. However, stress will deaden their use of knowledge and influence their professional judgment in estimating. In the construction industry, cost engineers can generally be divided into two main groups: clients’ cost engineers in consultant firms or in a development company who serve clients; and contractors’ cost engineers in construction companies working for the contractors. This study investigates the causal relationships between the stressors and stress of clients’ and contractors’ cost engineers. Two stressor–stress integrated models were developed for these two cost engineer groups by using the structural equation model. The findings revealed some stressors that affected both clients’ and contractors’ cost engineers: (1) poor environment, role conflict and work underload affect their stress positively; (2) social support and Type A behavior affect their stress negatively; and (3) work underload induces stress via the role conflict among cost engineers, their supervisors, and the organization. On the other hand, some deviations between these two groups of cost engineers also occur: (1) social support acts as a source of stressors of clients’ cost engineers; (2) a private life stressor only affects the stress of contractors’ cost engineers; and (3) a closed interactive looping relationship among role conflict, Type A behavior, and work underload affects contractors’ cost engineers. Based on the results of this study, some recommendations are suggested to manage cost engineers’ stress well. 相似文献
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Iron‐Oxide‐Based Nanovector for Tumor Targeted siRNA Delivery in an Orthotopic Hepatocellular Carcinoma Xenograft Mouse Model 下载免费PDF全文
Kui Wang Forrest M. Kievit Jonathan G. Sham Mike Jeon Zachary R. Stephen Arvind Bakthavatsalam James O. Park Miqin Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(4):477-487
Hepatocellular carcinoma (HCC) is one of the deadliest cancers worldwide. Small interfering RNA (siRNA) holds promise as a new class of therapeutics for HCC, as it can achieve sequence‐specific gene knockdown with low cytotoxicity. However, the main challenge in the clinical application of siRNA lies in the lack of effective delivery approaches that need to be highly specific and thus incur low or no systemic toxicity. Here, a nonviral nanoparticle‐based gene carrier is presented that can specifically deliver siRNA to HCC. The nanovector (NP‐siRNA‐GPC3 Ab) is made of an iron oxide core coated with chitosan‐polyethylene glycol (PEG) grafted polyethyleneimine copolymer, which is further functionalized with siRNA and conjugated with a monoclonal antibody (Ab) against human glypican‐3 (GPC3) receptor highly expressed in HCC. A rat RH7777 HCC cell line that coexpresses human GPC3 and firefly luciferase (Luc) is established to evaluate the nanovector. The nanoparticle‐mediated delivery of siRNA against Luc effectively suppresses Luc expression in vitro without notable cytotoxicity. Significantly, NP‐siLuc‐GPC3 Ab administered intravenously in an orthotopic model of HCC is able to specifically bound to tumor and induce remarkable inhibition of Luc expression. The findings demonstrate the potential of using this nanovector for targeted delivery of therapeutic siRNA to HCC. 相似文献
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Shivendu Prashar Derick Engles Sham Sunder Malik 《Photonic Network Communications》2018,35(2):258-264
This article demonstrates the effect of waveguide and material parameters on thermal sensitivity trends adopted by different cladding modes based on long-period fiber grating. Three-layer fiber geometry-based mathematical model has been implemented to estimate cladding modes. It is observed that for a cladding mode, the sign and magnitude of thermal sensitivity slope depend upon the designed grating period closer to period at dispersion turn around point. The \(\hbox {LP}_{10}\) and \(\hbox {LP}_{11}\) cladding modes have shown blueshift and maximum thermal sensitivity above all other modes at designed grating periods of 225 and \(195\,\upmu \hbox {m}\), respectively. The material parameter of fiber (thermo-optic coefficient) has also resulted in increment in sensitivity with the increase in difference amid its values for core and cladding region. 相似文献
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