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21.
Lisong Ai Lequan Zhang Wangde Dai Changhong Hu K. Kirk Shung Tzung K. Hsiai 《Journal of biomechanics》2010,43(14):2678-2683
Plaque rupture is the leading cause of acute coronary syndromes and stroke. Plaque formation, otherwise known as stenosis, preferentially occurs in the regions of arterial bifurcation or curvatures. To date, real-time assessment of stenosis-induced flow reversal remains a clinical challenge. By interfacing microelectromechanical system (MEMS) thermal sensors with the high frequency pulsed wave (PW) Doppler ultrasound, we proposed to assess flow reversal in the presence of an eccentric stenosis. We developed a 3-D stenotic model (inner diameter of 6 mm, an eccentric stenosis with a height of 2.75 mm, and width of 21 mm) simulating a superficial arterial vessel. We demonstrated that heat transfer from the sensing element (2×80 μm2) to the flow field peaked as a function of flow rates at the throat of the stenosis along the center/midline of arterial model, and dropped downstream from the stenosis, where flow reversal was detected by the high frequency ultrasound device at 45 MHz. Computational fluid dynamics (CFD) codes are in agreement with the ultrasound-acquired flow profiles upstream, downstream, and at the throat of the stenosis. Hence, we characterized regions of eccentric stenosis in terms of changes in heat transfer along the midline of vessel and identified points of flow reversal with high spatial and temporal resolution. 相似文献
22.
Amphiphilic block copolymers were synthesized by transesterification of hydrophilic methoxy poly(ethylene glycol) (mPEG) and hydrophobic poly(propylene fumarate) (PPF) and characterized. Four block copolymers were synthesized with a 2:1 mPEG:PPF molar ratio and mPEGs of molecular weights 570, 800, 1960, and 5190 and PPF of molecular weight 1570 as determined by NMR. The copolymers synthesized with mPEG of molecular weights 570 and 800 had 1.9 and 1.8 mPEG blocks per copolymer, respectively, as measured by NMR, representing an ABA-type block copolymer. The number of mPEG blocks of the copolymer decreased with increasing mPEG block length to as low as 1.5 mPEG blocks for copolymer synthesized with mPEG of molecular weight 5190. At a concentration range of 5-25 wt % in phosphate-buffered saline, copolymers synthesized with mPEG molecular weights of 570 and 800 possessed lower critical solution temperatures (LCST) between 40 and 45 degrees C and between 55 and 60 degrees C, respectively. Aqueous solutions of copolymer synthesized with mPEG 570 and 800 also experienced thermoreversible gelation. The sol-gel transition temperature was dependent on the sodium chloride concentration as well as the mPEG block length. The copolymer synthesized from mPEG 570 had a transition temperature between 40 and 20 degrees C with salt concentrations between 1 and 10 wt %, while the sol-gel transition temperatures of the copolymer synthesized from mPEG molecular weight 800 were higher in the range 75-30 degrees C with salt concentrations between 1 and 15 wt %. These novel thermoreversible copolymers are the first biodegradable copolymers with unsaturated double bonds along their macromolecular chain that can undergo both physical and chemical gelation and hold great promise for drug delivery and tissue engineering applications. 相似文献
23.
Twenty-five of 37Cryptococcus neoformans strains of known serotype produced the basidiomycetousFilobasidiella state either alone or when paired with a strain of compatible mating-type. Sixteen strains were mating-type, four strains were a mating-type, and five strains were self-fertile.F. neoformans serotypes A and D were interfertile with compatible mating-types ofF. bacillispora serotypes B and C.C. neoformans var.gattii was interfertile with compatible mating-types ofF. neoformans andF. bacillispora. F. bacillispora strains, which utilized creatinine andl-malic acid, were interfertile with compatible mating-types ofF. neoformans, which did not utilize creatinine andl-malic acid. The interfertility between serotypes and biotypes eliminates the need for recognizing the names ofC. neoformans var.gattii, C. bacillisporus, andF. bacillispora. It is proposed thatC. neoformans var.gattii andC. bacillisporus be regarded as later, facultative synonyms ofC. neoformans and thatF. bacillispora be regarded as a later, facultative synonym ofF. neoformans. 相似文献
24.
Aberrant frenum attachment would cause plaque accumulation and malalignment of teeth. It can be managed by frenotomy or frenectomy methods, through a conventional surgical technique or laser technique. Therefore, it is of interest to compare frenectomy healing surgical and laser techniques. Data from 51 outpatients and post-operative healing of frenectomy was assessed by Landry’s healing score index using 3 weeks postoperative photographs followed by statistical analysis. Based on the healing score index, the laser technique showed better outcomes than the surgical technique. Moreover, the association between the management of high frenal attachment and the healing score index was found to be statistically significant. 相似文献
25.
Cher Hon Lau Songlin Liu Donald R. Paul Jianzhong Xia Yan‐Ching Jean Hongmin Chen Lu Shao Tai‐Shung Chung 《Liver Transplantation》2011,1(4):634-642
An effective separation of CO2 from H2 can be achieved using currently known polyethylene oxide (PEO)‐based membranes at low temperatures but the CO2 permeability is inadequate for commerical operations. For commercial‐scale CO2/H2 separation, CO2 permeability of these membranes must be significantly enhanced without compromising CO2/H2 selectivity. We report here exceptional CO2/H2 separation properties of a nanohybrid membrane comprising polyethylene glycol methacrylate (PEGMA) grafts on an organic‐inorganic membrane (OIM) consisting of a low molecular weight polypropylene oxide (PPO)‐PEO‐PPO diamine and 3‐glycidyloxypropyltrimethoxysilane (GOTMS), an alkoxysilane. The CO2 gas permeability of this nanohybrid membrane can reach 1990 Barrer with a CO2/H2 selectivity of 11 at 35 °C for a mixed gas mixture comprising 50% CO2 ‐ 50% H2 at 3.5 atm. The transformation of the inorganic silica phase from a well‐dispersed network of finely defined nanoparticles to rough porous clusters appears to be responsible for this OIM membrane exceeding the performance of other state‐of‐the‐art PEO‐based membranes. 相似文献
26.
Wang H Ruan Z Li JJ Simpkins LM Smirk RA Wu SC Hutchins RD Nirschl DS Van Kirk K Cooper CB Sutton JC Ma Z Golla R Seethala R Salyan ME Nayeem A Krystek SR Sheriff S Camac DM Morin PE Carpenter B Robl JA Zahler R Gordon DA Hamann LG 《Bioorganic & medicinal chemistry letters》2008,18(11):3168-3172
Several series of pyridine amides were identified as selective and potent 11beta-HSD1 inhibitors. The most potent inhibitors feature 2,6- or 3,5-disubstitution on the pyridine core. Various linkers (CH(2)SO(2), CH(2)S, CH(2)O, S, O, N, bond) between the distal aryl and central pyridyl groups are tolerated, and lipophilic amide groups are generally favored. On the distal aryl group, a number of substitutions are well tolerated. A crystal structure was obtained for a complex between 11beta-HSD1 and the most potent inhibitor in this series. 相似文献
27.
Five different concentrations (100, 250, 500, 1000 and 2000 μg/L of aflatoxin B1 were found to be inhibitory to seed germination and seedling growth (root and shoot lengths) of mustard seeds (variety Pusa
bold). These also lowered the levels of chlorophyll and carotenoids in the emerging leaves during seedling growth. The inhibitory
effect was correlated with the concentration of applied toxin. 相似文献
28.
29.
In thoroughly washed guinea pig fundic gastric mucosal membranes, NaCl markedly potentiates the maximal histamine-stimulated adenylate cyclase activity and increases the concentration of histamine required for half-maximal effect (EC50). The apparent dissociation constants for the antagonists cimetidine and metiamide are only slightly increased in the presence of NaCl. Potassium chloride does not change the histamine EC50 but does increase the maximal histamine-stimulated adenylate cyclase activity. These results suggest that Na and K ions may play an important role in the regulation of histamine-sensitive adenylate cyclase in gastric mucosa. The effect of the Na ion appears to be more specific for histamine H2 receptor agonists than for antagonists. 相似文献
30.
Shung -Chang Jong Jeannette M Birmingham 《World journal of microbiology & biotechnology》1989,5(4):411-450
Summary Fungal biotechnology has generated a voluminous amount of technical literature and scientific data. Patents probably contain the most complete and detailed information about the use of fungal cultures in biotechnology. This article contains a brief review of the United States patent system where microorganisms form an integral part of the disclosure and explains the role of the American Type Culture Collection (ATCC) as a patent culture depository. A list based on the application of the ATCC fungal strains which have been cited or used in US patents and the names of the inventors, the titles of the inventions, and their patent numbers are included. This provides resource material particularly for developing countries as they begin to establish their own biotechnology. 相似文献