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排序方式: 共有184条查询结果,搜索用时 578 毫秒
31.
Christopher E. Denes Alexander J. Cole Yagiz Alp Aksoy Geng Li Graham Gregory Neely Daniel Hesselson 《International journal of molecular sciences》2021,22(16)
Modification of the human genome has immense potential for preventing or treating disease. Modern genome editing techniques based on CRISPR/Cas9 show great promise for altering disease-relevant genes. The efficacy of precision editing at CRISPR/Cas9-induced double-strand breaks is dependent on the relative activities of nuclear DNA repair pathways, including the homology-directed repair and error-prone non-homologous end-joining pathways. The competition between multiple DNA repair pathways generates mosaic and/or therapeutically undesirable editing outcomes. Importantly, genetic models have validated key DNA repair pathways as druggable targets for increasing editing efficacy. In this review, we highlight approaches that can be used to achieve the desired genome modification, including the latest progress using small molecule modulators and engineered CRISPR/Cas proteins to enhance precision editing. 相似文献
32.
Alp Manavbasi Kevin Bodily Taylor Clarke Keith Johnson Byron Estes 《Metal Finishing》2013,111(6):12-15
Corrosion resistance of anodized aluminum sealed with conventional and a new sealant was tested against the alkaline, acid and neutral chloride salt solutions. The results show that the conventional water based sealants have good acid and Neutral Salt Fog resistance; however, they do not possess the necessary alkaline corrosion resistance to be used for decorative and automotive exterior applications. A new anodic coating sealant was developed to provide the necessary alkaline corrosion resistance along with the acid and neutral salt attack resistance. Acid Dissolution Test (ADT) Rating, Alkaline Corrosion Resistance, Neutral Salt Fog, Heat Resistance and Alkaline Car Wash Detergent tests were done in accordance with General Motors Spec GMW 14665. Results revealed that this novel sealant is significantly capable of meeting the rigorous GMW 14665 specification and can be used for sealing the anodic coatings used in automotive exterior applications. 相似文献
33.
Mirac Alaf Mehmet Oguz Guler Deniz Gultekin Mehmet Uysal Ahmet Alp Hatem Akbulut 《Vacuum》2008,83(2):292-301
In this work, microstructural and physical properties were studied in the tin oxide films deposited by thermal evaporation of Sn films on stainless steel substrates followed by in situ D.C. plasma oxidation at 200 °C substrate temperature. The surface properties were studied by scanning electron microscopy, X-ray diffraction, atomic force microscopy and four-point probe electrical resistivity. The typical calculated grain size of the films deposited by thermal evaporation was between 28 nm and 66 nm and the texture structure was found to be dependent on the thermal deposition pressure. A cassiterite structure of SnO2 was produced by D.C. plasma oxidation with the main diffraction peaks of the (101), (200), (211), (310) and (221) planes at the 25% and 50% O2 partial pressure conditions. However, at 12.5% O2 partial pressure oxidation conditions, amorphous tin oxide structure and crystalline SnO phases were detected. Increasing thermal deposition pressure resulted in preferential texture formation at (211) and (310) planes. The surface structure investigation of the produced films by SEM and AFM studies showed large SnO2 islands with approximately 1.0 μm and 1.5 μm sized nodules, and they are called as grape-like structures. The grape-like grains possess nano grains, which are between 20 nm and 30 nm in diameter calculated by Scherer's formula. The grape-like grains were seen to be separated by large cavities and the size of these cavities and nano grains was seen to be larger when the O2 partial pressure is increased. The four-point probe resistivity of the films, grown at different oxidation temperatures, decreased with the increase in oxygen partial pressure. The values of resistivity for SnO2 phase were measured as low as 10−5 Ω-cm and observed to decrease with increasing thermal deposition pressure and oxygen partial pressure. 相似文献
34.
Effects of Er:YAG laser on bond strength of self‐etching adhesives to caries‐affected dentin
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Alp Erdin Koyuturk Bilal Ozmen Murat Cortcu Ugur Tokay Gul Tosun Mustafa Erhan Sari 《Microscopy research and technique》2014,77(4):282-288
The erbium:yttrium–aluminum–garnet (Er:YAG) laser may be effective the bond strength of adhesive systems on dentine surfaces, the chemical composition and aggressiveness of adhesive systems in clinical practice. The purpose of this study was to evaluate the effects of the Er:YAG laser system with the bonding ability of two different self‐etching adhesives to caries‐affected dentine in primary molars. Ninety mid‐coronal flat dentine surfaces obtained from sound and caries‐affected human primary dentine were treated with an Er:YAG laser or a bur. The prepared surfaces were restored with an adhesive system (Xeno V; Clearfil S3) and a compomer (Dyract Extra). The restored teeth were sectioned with a low‐speed saw and 162 samples were obtained. The bond strength of the adhesive systems was tested using the micro‐tensile test method. The data were statistically analyzed. A restored tooth in each group was processed for scanning electron microscopy evaluation. The values of the highest bond strength were obtained from the Clearfil S3‐Er:YAG laser‐sound dentine group in all groups. (24.57 ± 7.27 MPa) (P > 0.05). The values of the lowest bond strength were obtained from the Xeno V‐Er:YAG laser‐sound dentine group in all groups (11.01 ± 3.89 MPa). It was determined that the Clearfil S3 increased the bond strength on the surface applied with Er:YAG laser according to the Xeno V. Microsc. Res. Tech. 77:282–288, 2014. © 2014 Wiley Periodicals, Inc. 相似文献
35.
Ari E Kaya Y Demir H Cebi A Alp HH Bakan E Odabasi D Keskin S 《Hemodialysis international. International Symposium on Home Hemodialysis》2011,15(4):453-459
Oxidative stress is accepted as a nonclassical cardiovascular risk factor in chronic renal failure patients. The aim of this study was to evaluate the relation between oxidative DNA damage (8‐hydroxy‐2′‐deoxyguanosine/deoxyguanosine [8‐OHdG/dG] ratio), oxidative stress biomarkers, antioxidant enzymes, and carotid artery intima‐media thickness (CIMT) in hemodialysis (HD) patients. Forty chronic HD patients without known atherosclerotic disease and 48 age‐ and sex‐matched healthy individuals were included in the study. Plasma malondialdehyde (MDA) levels and 8‐OHdG/dG ratio were determined as oxidative stress markers. Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured as antioxidants. CIMT was assessed by carotid artery ultrasonography. 8‐OHdG/dG ratios and MDA levels were higher; SOD and GPx activities were lower in HD patients compared to controls. HD patients had significantly higher CIMT compared to controls (0.61 ± 0.08 vs. 0.42 ± 0.05, p < 0.001). There was a significant positive correlation between CIMT and 8‐OHdG/dG ratio (r = 0.57, p < 0.01) and MDA levels (r = 0.41, p < 0.01), while there was a significant negative correlation between CIMT and SOD (r = ?0.47, p < 0.01) and GPx levels (r = ?0.62, p < 0.01). It is firstly demonstrated that CIMT is positively correlated with oxidative DNA damage in HD patients without known atherosclerotic disease. 相似文献
36.
Agar BU Akonur A Cheung AK Leypoldt JK 《Hemodialysis international. International Symposium on Home Hemodialysis》2011,15(Z1):S9-S14
We have recently developed a pseudo one-compartment model to describe intradialytic and postdialytic rebound kinetics of plasma phosphorus. In this model, individual patient differences in phosphorus kinetics were characterized by a single parameter; the phosphorus mobilization clearance (K(M) ). In this work, we propose a simple method to estimate K(M) from predialytic and postdialytic plasma phosphorus concentrations. Clinical data were collected from 22 chronic hemodialysis patients that underwent a 4-hour treatment session. A simple algebraic equation was derived from the pseudo one-compartment model to determine K(M) from predialytic and postdialytic plasma phosphorus concentrations. K(M) values computed using this equation were compared with values obtained from nonlinear regression of the full kinetic model to frequent intradialytic and postdialytic measurements of plasma phosphorus concentrations. There was good agreement between K(M) values (concordance correlation coefficient of 0.94) obtained from the simple method (105?±?52?mL/min, mean?±?SD) and from the full model (99?±?47?mL/min). The 95% confidence interval for the difference between estimated K(M) values was -26 to 36?mL/min. The proposed simple method requires the use of only predialytic and postdialytic blood samples to estimate patient specific K(M) ; this approach may allow easy clinical evaluation of phosphorus kinetics in hemodialysis patients. 相似文献
37.
Alp H. Alidedeoglu Kevin Davis Rhonda Robertson Crystal Smith James W. Rawlins Sarah E. Morgan 《Journal of Coatings Technology and Research》2011,8(1):45-52
Environmental regulations are forcing the reformulation of many decorative and protective coatings systems. In particular,
air-drying solventborne alkyd paints need to meet increasingly stringent emission limits and often must be reformulated with
suitable exempt solvents or reactive diluents to achieve volatile organic compound (VOC) reduction. In the research summarized
in this article, a new reactive diluent, tetra(2,7-octadienyl) titanate, was synthesized and evaluated in alkyd formulations
for VOC reduction and property enhancement. A soy-based long-oil alkyd resin; a soy-based high-solids, long-oil alkyd resin;
and a linseed-based, high-solids long-oil alkyd resin were evaluated in combination with the new reactive diluent at weight
percentages ranging from 10% to 50%. Characterization included measuring viscosity, film dry times, and film performance of
the reactive diluent formulations in comparison to neat alkyd resins used as control. The tetra(2,7-octadienyl) titanate formulations
consistently exhibited reduced viscosities and dry times as a function of concentration. The resulting films were harder and
more thoroughly cured than the control systems. 相似文献
38.
In this study, optimization of some parameters of stirred mill on ultra-fine grinding of refractory Au/Ag ores was performed. A three-level Box-Behnken design combining a response surface methodology (RSM) with quadratic programming (QP) was employed for modelling and optimization of some operating parameters in ultra-fine grinding. Grinding tests were carried out in a laboratory scale pin-type vertical stirred mill. The relationship between the response, i.e. d80 size, and four grinding parameters, i.e. ball diameter, grinding time, ball charge ratio and stirrer revolution was presented as empirical model equations. Analysis of variance showed a high coefficient of determination value (R2 = 0.9698), thus ensuring a satisfactory of the second-order regression model with the experimental data.The model equations were then optimized using the quadratic programming method to minimize for d80 size within the experimental range studied. The optimum conditions were found to be 1.61 mm for ball diameter, 11.50 min for grinding time, 80% for ball charge ratio and 745 rpm for stirrer revolution for this grinding process.In order to verify the improvement of grinding performance using the optimal level of control factors three verification experiments were conducted, and the results for d80 was 3.37 μm, which were smaller than those obtained in the initial tests. 相似文献
39.
Extraction of Ti(IV) from its aqueous hydrochloric acid solutions into organic Alamine 336-m-xylene systems was investigated. Extraction experiments were conducted with three different initial metal concentrations of 1, 3, and 6 mg/mL, each at three acidic molarities of 1, 5, and 10 M. It was observed that the extractability of Ti(IV) increases with increasing acidic molarities. Alamine 336 diluted with m-xylene was found to be a suitable extractant for Ti(IV) across this acidic range. In parallel, a mathematical model was developed to correlate metal extractability and Alamine 336 volume content. Optimal Alamine 336 contents were estimated for single-stage extraction. 相似文献
40.