Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy

The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg alloy.The AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg alloy.Refining elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-Al.At a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and net-shrinkage.With an increase in slow shot speed,the size and number of ESCs and porosities significantly reduce.In addition,the distribution of ESCs is more dispersed and the net-shrinkage disappears.The tensile property is greatly improved by adopting a higher slow shot speed.The ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%).

C-reactive protein as a predictor of malignant ventricular arrhythmias in non-ST elevation myocardial infarction

Objective To investigate whether C-reactive protein (CRP) is a biomarker of malignant ventricular arrhythmias (MVA) occurring in non-ST elevation myocardial infarction (NSTEMI) patients with Global Registry of Acute Coronary events (GRACE) scores < 140. Methods A total of 1450 NSTEMI patients were included in this study. Hs-CRP blood levels were measured via a turbidimetric immunoassay after confirming the diagnosis of NSTEMI with GRACE scores < 140. Results Consistent with prior studies, the MVA occurrence rate in our cohort was 6.7%, and patients with MVA exhibited a reduced left ventricular ejection fraction (46.1%± 6.9% vs. 61.5%± 8.7%, P = 0.032), a higher incidence of Killip classification > 1 (34.1% vs. 24.2%, P < 0.001), an increased surgical revascularization rate (34.1% vs. 9.7%, P < 0.001), and increased mortality (16.5% vs. 5.8%, P < 0.001). Serum hs-CRP levels were higher (P = 0.003) in NSTEMI patients with MVA, and this increase appeared unrelated to other clinical parameters. The C-statistic to discriminate MVA was 0.82 (95% CI: 0.74–0.89). Using receiver operating characteristics analysis, we optimized a cutoff point of 16 mL/L, and the sensitivity and specificity were 95% and 61%, respectively;the positive predictive value was 20% and the negative predictive value was 99%. Conclusions An hs-CRP assay is a potential MVA biomarker in low-risk NSTEMI patients with GRACE scores < 140. If validated in prospective studies, hs-CRP may offer a low-cost supplementary strategy for risk stratification for NSTEMI patients.

Combination and distribution of reservoir space in complex carbonate rocks

This paper discusses the reservoir space in carbonate rocks in terms of types,combination features,distribution regularity,and controlling factors,based on core observations and tests of the North Truva Oilfield,Caspian Basin.According to the reservoir space combinations,carbonate reservoirs can be divided into four types,i.e.,pore,fracture-pore,pore-cavity-fracture,and pore-cavity.Formation and distribution of these reservoirs is strongly controlled by deposition,diagenesis,and tectonism.In evaporated platform and restricted platform facies,the reservoirs are predominately affected by meteoric fresh water leaching in the supergene-para-syngenetic period and by uplifting and erosion in the late stage,making both platform facies contain all the above-mentioned four types of reservoirs,with various pores,such as dissolved cavities and dissolved fractures,or structural fractures occasionally in favorable structural locations.In open platform facies,the reservoirs deposited continuously in deeper water,in an environment of alternative high-energy shoals（where pore-fracture-type reservoirs are dominant） and low-energy shoals（where pore reservoirs are dominant）.

Acute- and Long-term Outcomes of Rotational Atherectomy followed by Cutting Balloon versus Plain Balloon before Drug-Eluting Stent Implantation for Calcified Coronary Lesions

Background： Coronary calcification is a major determinant ofstent underexpansion and subsequent adverse events. This study aimed to evaluate the acute- and long-term outcomes of rotational atherectomy （RA） followed by cutting balloon （CB） versus plain balloon before drug-eluting stent implantation for calcified coronary lesions. Methods： From June April 2013 to March 2016, a total of 127 patients with moderately or severely calcified coronary lesions were treated with RA. Patients were divided into two groups according to the balloon type after RA： RA＋CB group （n = 75） and RA＋plain balloon group （n = 52）. Minimal lumen diameter and acute lumen gain were analyzed by quantitative coronary angiography. In-hospital and long-term （〉1 year） outcomes were recorded. Multivariate Cox regression analysis was performed to determine the independent predictors of in-stent restenosis.Results： The mean age of the patients was 65.5 years, and 76.4% were men. Total lesion length and minimal lumen diameter at baseline were similar in the two groups. After RA and balloon dilation, the lumen diameter was significantly larger in the RA＋CB group than in the RA＋plain balloon group （1.57 ±0.46 mm vs. 1.10 ± 0.40 mm, t = 4.123, P 〈 0.001）. The final lumen diameter was also larger in the RA＋CB group compared to that in the RA group （2.81± 0.41 mm vs. 2.60± 0.25 ram, t = 2.111, P = 0.039）. Moreover, patients receiving RA and CB tended to have larger final lumen gain （2.15 - 0.48 mm vs. 1.95 ± 0.47 mm, t = 1.542, P = 0.132）. Multivariate Cox regression analysis indicated that the strategy of RA＋CB was a significant protective factor against long-term （〉1 year） in-stent restenosis （hazard ratio： 0.136, 95% confidence interval： 0.020-0.936, P = 0.043）. Conclusions： In patients with moderately or severely calcified lesions, a strategy of RA followed by CB before stent implantation can increase lumen diameter and acute lumen gain. This strategy is safe with lower risk of long-term in-stent restenosis.