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排序方式: 共有678条查询结果,搜索用时 15 毫秒
1.
Inam Ridha Ali Basiri Sudhakar Godeshala Md Zubair Ebne Rafique Deepanjan Ghosh Jason Williams Nikhilesh Chawla Jung Keun Lee Jacquelyn Kilbourne Yu Yao Kaushal Rege 《Advanced functional materials》2021,31(6):2007811
Poor strength, infection, leakage, long procedure times, and inflammation limit the efficacy of common tissue sealing devices in surgeries and trauma. Light-activated sealing is attractive for tissue sealing and repair, and can be facilitated by the generation of local heat following absorption of nonionizing laser energy by chromophores. Here, the inherent ability of biomaterials is exploited to absorb nonionizing, mid-infrared (midIR) light in order to engender rapid photothermal sealing and repair of soft tissue wounds. In this approach, the biomaterial simultaneously acts as a photothermal convertor as well as a biosealant, which dispenses the need for exogeneous light-absorbing nanoparticles or dyes. Biomechanical recovery, mathematical modeling, histopathology analyses, tissue strain mapping using digital imaging correlation, and visualization of the biosealant-tissue interface using hyperspectral imaging indicate superior performance of midIR sealing in live mice compared to conventional sutures and glue. The midIR-biosealant approach demonstrates rapid sealing of soft tissues, improves cosmesis, lowers potential for scarring, obviates safety concerns because of the nonionizing light used, and allows adoption of a wide diversity of biomaterials. Taken together, the studies demonstrate a novel advance both in biomaterials for surgical sealing along with the use of nonionizing midIR light, with high potential for clinical translation. 相似文献
2.
Measurements in the CROCUS reactor at EPFL, Lausanne, are reported for the critical water level and the inverse reactor period for several different sets of delayed supercritical conditions. The experimental configurations were also calculated by four different calculation methods. For each of the supercritical configurations, the absolute reactivity value has been determined in two different ways, viz.: (i) through direct comparison of the multiplication factor obtained employing a given calculation method with the corresponding value for the critical case (calculated reactivity: ρcalc); (ii) by application of the inhour equation using the kinetic parameters obtained for the critical configuration and the measured inverse reactor period (measured reactivity: ρmeas). The calculated multiplication factors for the reference critical configuration, as well as ρcalc for the supercritical cases, are found to be in good agreement. However, the values of ρmeas produced by two of the applied calculation methods differ appreciably from the corresponding ρcalc values, clearly indicating deficiencies in the kinetic parameters obtained from these methods. 相似文献
3.
4.
Many of the targeted applications for powder-metallurgy materials, particularly in the automotive industry, undergo cyclic
loading. It is, therefore, essential to examine the fatigue mechanisms in these materials. The mechanisms of fatigue-crack
initiation and propagation in ferrous powder-metallurgy components have been investigated. The fatigue mechanisms are controlled
primarily by the inherent porosity present in these materials. Since most, if not all, fatigue cracks initiate and propagate
at the specimen surface, surface replication was used to determine the role of surface porosity in relation to fatigue behavior.
Surface replication provides detailed information on both initiation sites and on the propagation path of fatigue cracks.
The effect of microstructural features such as pore size and pore shape, as well as the heterogeneous microstructure on crack
deflection, was examined and is discussed. Fracture surfaces were examined to elucidate a mechanistic understanding of fatigue
processes in these materials. 相似文献
5.
We have isolated a mutant which exhibits partial constitutivity for a -specific gene expression in α cells. The wild-type gene was cloned and demonstrated to be allelic to the STE13 gene, which encodes the dipeptidyl aminopeptidase involved in processing of the α-factor prepropheromone. Thus, the mating defect of the ste13 mutations in α cells may result both from the production of incompletely processed α-factor and from the increased expression of a -specific genes. The STE13 open reading frame of 931 amino acids contains a putative membrane-spanning segment near its amino terminus and is 31% identical to a second yeast dipeptidyl aminopeptidase (DAP2). A null mutant of STE13 has been constructed: it is viable and sporulation-proficient. The sequence has been deposited in the GenBank data library under Accession Number L21944. 相似文献
6.
A review is provided of the use of analytical models and two dimensional (2D) and three dimensional (3D) microstructure based
FEM models to accurately predict the properties of particle reinforced composite materials. It is shown that analytical models
do not account for the microstructural factors that influence the mechanical behavior of the material. 2D models do capture
the anisotropy in deformation behavior induced by anisotropy in particle orientation. The experimentally-observed dependence
of Young's modulus and tensile strength is confirmed by the 2D microstructure-based numerical model. However, because of the
2D stress state, a realistic comparison to actual experimental values is not possible. A serial sectioning process can be
used to reproduce and visualize the 3D microstructure of particle reinforced metal matrix composites. The 3D microstructure-based
FEM accurately represents the alignment, aspect ratio, and distribution of the particles. Comparison with single particle
and multiparticle models of simple shape (spherical and ellipsoidal) shows that the 3D microstructure-based approach is more
accurate in simulating and understanding material behavior. 相似文献
7.
8.
RK Dhiman AK Seth S Jain YK Chawla JB Dilawari 《Canadian Metallurgical Quarterly》1998,43(6):1311-1316
Results of eight multicenter, randomized, placebo-controlled, double-blind, parallel-group studies were pooled to assess the efficacy of the angiotensin II-receptor blocker irbesartan over the dose range of 1 to 900 mg. A total of 2955 adults with a seated diastolic blood pressure of 95 to 110 mm Hg were randomized to treatment with oral irbesartan once daily or placebo for 6 to 8 weeks. Office blood pressure was measured at trough (24+/-3 hours after the last dose) and peak (3+/-1 hours after the last dose) by mercury sphygmomanometry. Demographic characteristics (mean blood pressure; 151/101 mm Hg; mean age, 54 years; 63% male; and 82% white) were similar across all dose groups. After the groups were pooled, antihypertensive efficacy was assessed by therapeutic response (trough seated diastolic blood pressure <90 mm Hg or a reduction from baseline of > or = 10 mm Hg) and by modeling of the maximum reductions in trough and peak seated diastolic and systolic blood pressure. Antihypertensive effects increased with increasing doses and reached a plateau at > or = 300 mg. Irbesartan 150 mg provided placebo-subtracted reductions in trough seated systolic and diastolic blood pressure of approximately 8 and approximately 5 mm Hg, respectively, with 56% of patients displaying a favorable response. In conclusion, irbesartan provides clinically significant blood pressure lowering, with a clear relationship between (log) dose and antihypertensive effect. 相似文献
9.
Luis Carlos Ferreira Jr.Marcos A.S. Costa Pedro Ivo C. GuimarãesLuiz Claudio de Santa Maria 《Polymer》2002,43(14):3857-3862
Styrene polymerization was carried out with Ni(acac)2/MAO and Ni(acac)2/SiO2/MAO. The influence of reaction parameters (Al/Ni mole ratio, catalyst concentration, temperature and time polymerization) on styrene polymerization was evaluated. It was observed that both catalytic systems were affected by reaction parameters and that the heterogeneous catalyst presented higher activity than the homogeneous one. Polystyrenes with different molecular weight, stereoregularity and polydispersity were obtained. These results suggest that different active catalyst species could have been present. In addition, two types of methylaluminoxane (MAO) with different molecular weights were also evaluated as cocatalyst. As a result, the catalyst activity and stereospecificity were strongly affected by the MAO type. 相似文献
10.
M. A. Dudek R. S. Sidhu N. Chawla 《JOM Journal of the Minerals, Metals and Materials Society》2006,58(6):57-62
Severallead-free material systems are availableas replacements for traditional lead-based solders in microelectronic packaging,
including near-eutectic combinations oftin-rich alloys. Although these materials have superior mechanical properties as compared
to the Pb-Sn system, much work remains in developing these materials for electronic packaging. Small additions of rare-earth
elements have been shown to refine the microstructure of several lead-free solder systems, thus improving their mechanical
properties. This study investigated the effect of the addition of lanthanum on the melting behavior, microstructure, and shear
strength of an Sn-3.9Ag-0.7Cu alloy. The influence of LaSn3 intermetallics on microstructural refinement and damage evolution in these novel solders is discussed. 相似文献