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排序方式: 共有235条查询结果,搜索用时 31 毫秒
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R B Singh M A Niaz R Beegom G S Wander A S Thakur H S Rissam 《Journal of the American College of Nutrition》1999,18(3):268-273
OBJECTIVE: To determine the association between body fat percent and prevalence of coronary artery disease (CAD) and coronary risk factors in subjects with low rates of obesity. SUBJECTS AND METHODS: We randomly selected 850 men, aged 25 to 64 years. The survey methods were questionnaire and bioelectrical impedance analysis for body composition. Subjects were divided into high-fat (n = 357), over-fat (n = 230), normal-fat (n = 200) and under-fat (n = 63) based on criteria of body-fat percent analysis. RESULTS: The prevalence of CAD and the coronary-risk factors hypercholesterolemia, hypertension, diabetes, mellitus and sedentary lifestyle were significantly associated with high and moderate body fat percent despite low body-mass index (23.6+/-4.1 kg/m2). Mean total cholesterol, triglycerides and blood pressure were significantly associated with high and moderate body fat percent. The prevalence of smoking was weakly but inversely associated with high body-fat percent. Mean HDL cholesterol was positively associated with high body-fat percent. Body mass index was positively associated with high body-fat percent. CONCLUSIONS: High and moderate body-fat-percent subjects were associated with high prevalence of CAD and the coronary-risk factors hypertension, diabetes mellitus, higher body-mass index and sedentary lifestyle. 相似文献
3.
Zhang Xu Jung-Hyun Choi David L. Dai Jun Luo Reese Jalal Ladak Qian Li Yimeng Wang Christine Zhang Shane Wiebe Alex C. H. Liu Xiaozhuo Ran Jiaqi Yang Parisa Naeli Aitor Garzia Lele Zhou Niaz Mahmood Qiyun Deng Mohamed Elaish Rongtuan Lin Lara K. Mahal Tom C. Hobman Jerry Pelletier Tommy Alain Silvia M. Vidal Thomas Duchaine Mohammad T. Mazhab-Jafari Xiaojuan Mao Seyed Mehdi Jafarnejad Nahum Sonenberg 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(32)
4.
Ali K. Shargh Aude Picard Rostislav Hrubiak Dongzhou Zhang Russell J. Hemley Shanti Deemyad Niaz Abdolrahim Saveez Saffarian 《Proceedings of the National Academy of Sciences of the United States of America》2022,119(27)
Formation of vitreous ice during rapid compression of water at room temperature is important for biology and the study of biological systems. Here, we show that Raman spectra of rapidly compressed water at greater than 1 GPa at room temperature exhibits the signature of high-density amorphous ice, whereas the X-ray diffraction (XRD) pattern is dominated by crystalline ice VI. To resolve this apparent contradiction, we used molecular dynamics simulations to calculate full vibrational spectra and diffraction patterns of mixtures of vitreous ice and ice VI, including embedded interfaces between the two phases. We show quantitatively that Raman spectra, which probe the local polarizability with respect to atomic displacements, are dominated by the vitreous phase, whereas a small amount of the crystalline component is readily apparent by XRD. The results of our combined experimental and theoretical studies have implications for detecting vitreous phases of water, survival of biological systems under extreme conditions, and biological imaging. The results provide additional insight into the stable and metastable phases of H2O as a function of pressure and temperature, as well as of other materials undergoing pressure-induced amorphization and other metastable transitions.Life as we know it on Earth depends on water. However, water also poses a critical challenge to life when it freezes at atmospheric pressure and low temperatures. The crystallization of H2O to form hexagonal ice () under these conditions is accompanied by its well-known expansion, which has a dramatic impact on the structure and function of living cells. This crystallization of H2O disrupts biological membranes and intracellular organization in living organisms and also displaces and concentrates salts and nutrients in the space between crystals (1). Like many liquids, however, rapid cooling of H2O at ambient pressure to below its glass-transition temperature results in the formation of an amorphous phase known as low-density amorphous ice. Amorphous solid H2O provides a chance for biological functions to survive where life otherwise cannot exist. Low-density amorphous ice is not the only amorphous form of H2O. Ice Ih transforms to high-density amorphous (HDA) ice by application of ∼1 GPa of pressure at temperatures below 130 K (2, 3). In addition, a distinct, very-high-density amorphous state (vHDA) can form by isobaric heating and cooling of the HDA (4). low-density amorphous, high-density amorphous, and very-high-density amorphous state ice thus represent the three dominant, solid amorphous forms of H2O at low temperatures.Solid amorphous phases of H2O are broadly important in biology and biological applications. That amorphous H2O which can exist over a broad range of temperatures, from cryogenic conditions to room temperature, is particularly interesting in the context of biological systems. Managing ice crystals is vital for extremophiles to survive damaging effects of H2O crystallization. These organisms inhibit the growth of ice crystals and regulate the size and shape of the crystals using special antifreeze proteins (5, 6). Additionally, amorphous phases of H2O are important in preserving biological samples in cryotomography applications. In cryotomography, the amorphous H2O at low temperature is utilized routinely for sample preparation (7, 8), and significant efforts have been devoted to increase information obtained from cryotomography techniques. The low-temperature regime of amorphous H2O routinely accessed in cryotomography creates challenges for light microscopy due to freezing of index-matching medium and objectives, which result in lowering the resolution of light microscopy in these applications. Room-temperature amorphous phases of H2O are, therefore, advantageous for light microscopy applications and further development of techniques such as correlative light and electron microscopy (9–11).While formation of amorphous phases of H2O below 200 K has been reported in many studies (2, 3, 12–16), a particularly interesting result is the observation of the Raman signature of HDA ice during fast compression of water at room temperature and moderate pressures (17). On the other hand, independent X-ray diffraction (XRD) measurements of H2O on fast compression could not verify the formation of amorphous H2O above 200 K (18). Here, we report high-resolution micro-Raman and synchrotron XRD measurements conducted in parallel in rapidly compressed samples of water in diamond anvil cells (DACs). Our findings, that are supported by molecular dynamics simulations, shed light on the nature of the HDA ice at room temperature and reconciled conflicting previous reports. 相似文献
5.
In this study, an artificial intelligence tool called gene expression programming (GEP) has been successfully applied to develop an empirical model that can predict the shear strength of steel fiber reinforced concrete beams. The proposed genetic model incorporates all the influencing parameters such as the geometric properties of the beam, the concrete compressive strength, the shear span-to-depth ratio, and the mechanical and material properties of steel fiber. Existing empirical models ignore the tensile strength of steel fibers, which exercise a strong influence on the crack propagation of concrete matrix, thereby affecting the beam shear strength. To overcome this limitation, an improved and robust empirical model is proposed herein that incorporates the fiber tensile strength along with the other influencing factors. For this purpose, an extensive experimental database subjected to four-point loading is constructed comprising results of 488 tests drawn from the literature. The data are divided based on different shapes (hooked or straight fiber) and the tensile strength of steel fiber. The empirical model is developed using this experimental database and statistically compared with previously established empirical equations. This comparison indicates that the proposed model shows significant improvement in predicting the shear strength of steel fiber reinforced concrete beams, thus substantiating the important role of fiber tensile strength. 相似文献
6.
Sanjay Pandanaboyana Devender Mittapalli Ahsan Rao Raj Prasad Niaz Ahmad 《The surgeon》2014,12(2):87-93
BackgroundThis metaanalysis was designed to systematically analyse all published randomized controlled trials comparing self-gripping mesh (ProGrip) and sutured mesh to analyse early and long term outcomes for open inguinal hernia repair.MethodsA literature search was performed using the Cochrane Colorectal Cancer Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials in the Cochrane Library, MEDLINE, Embase and Science Citation Index Expanded. Randomized trials comparing self-gripping mesh with sutured mesh were included. Statistical analysis was performed using Review Manager Version 5.2 software. The primary outcome measures were hernia recurrence and chronic pain after operation. Secondary outcome measures included surgical time, wound complications and perioperative complications.ResultsFive randomized trials were identified as suitable, including 1170 patients. There was no significant difference between the two types of mesh repairs in perioperative complications, wound haematoma, chronic groin pain and hernia recurrence. Wound infection was lower in self gripping mesh group compared to sutured mesh but this was not statistically significant (risk ratio (RR) 0.57, 95% confidence interval 0.30–1.06, P = 0.08). The duration of operation was significantly shorter with self-gripping mesh compared to sutured mesh with a mean difference of ?5.48 min [?9.31, ?1.64] Z = 2.80 (P = 0.005).ConclusionSelf-gripping mesh was associated with shorter operative time compared to sutured mesh. Both types of mesh repairs have comparable perioperative and long term outcomes. 相似文献
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8.
Ureteric reconstruction for the management of transplant ureteric stricture: a decade of experience from a single centre
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Thomas W. Pike Sanjay Pandanaboyana Thea Hope‐Johnson Lutz Hostert Niaz Ahmad 《Transplant international》2015,28(5):529-534
This study was conducted to review the outcomes of patients who had undergone surgical repair of a ureteric stricture following renal transplantation. All patients who developed a ureteric stricture and underwent ureteric reconstruction following renal transplantation, between December 2003 and November 2013, were reviewed. One thousand five hundred and sixty renal transplants were performed during the study period. Forty patients required surgical repair of a ureteric stricture (2.5%, 25 male, median age 48 [14–78]). The median time to stricture was 3 [1–149] months. 19 patients were reconstructed by reimplantation to the bladder, 18 utilized a Boari flap, two were a pre‐existing ileal conduit and one was an anastomosis to a native ureter. In one patient, reconstruction was impossible and consequently an extra‐anatomic stent was used. Two patients required re‐operation for restricture and kinking. Median serum creatinine at 12 months following surgery was 148 [84–508] μmol/l. There was no 90‐day mortality. Eleven grafts were lost at the time of this study, a median time of 11 [1–103] months after reconstruction. The incidence of ureteric stricture following renal transplant is low. Surgical reconstruction of the transplant ureter is the optimal treatment and is successful in the majority of patients. 相似文献
9.
Non‐HLA‐matched 3rd party vascular allograft in renal transplant may lead to sensitization against donor HLA
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Henry Watson Rupaly Pande Shahid Farid Clare Ecuyer Richard Baker Brendan Clarke Niaz Ahmad 《Clinical transplantation》2016,30(11):1508-1512
3rd party donor vessels are often used for vascular reconstruction in organ transplantation. While current practice ensures that 3rd party vessels are blood group matched, HLA matching to the non‐intended recipient is not performed. This practice potentially sensitizes the recipient and may reduce their future chance of renal transplant from a larger pool of donors. We examined our cohort of renal transplant recipients who received non‐HLA‐matched 3rd party vessels for the de‐novo development of donor‐specific HLA antibodies. Our institution's Human Tissue Authority (HTA) blood vessel registers were examined to identify stored donor vessels and their non‐intended recipients. Donor vessel HLA status was cross‐referenced with the recipient HLA status. Between 2004 and 2014, five patients were identified that received 3rd party non‐HLA‐matched vessels for vascular reconstruction during renal transplantation. Three patients (60%) subsequently developed donor‐specific HLA antibodies. These data provide evidence that use of non‐HLA‐matched stored 3rd party vascular grafts may lead to sensitization in the recipient. Where time permits, HLA matching should be performed to avoid this allogeneic response. Laboratories monitoring DSA should be aware of any patient receiving a non‐HLA‐matched 3rd party vascular graft, and recipients may benefit from increased post‐transplant immunological vigilance. 相似文献
10.
Niaz Al-Somai Mohammed Al-Muhur Osama Quteimat Nashaat Hamzah 《Saudi Pharmaceutical Journal》2014,22(6):516-521