A general metrology of stress on crystalline silicon with random crystal plane by using micro-Raman spectroscopy

The requirement of stress analysis and measurement is increasing with the great development of heterogeneous structures and strain engineering in the field of semiconductors.Micro-Raman spectroscopy is an effective method for the measurement of intrinsic stress in semiconductor structures.However,most existing applications of Raman-stress measurement use the classical model established on the (001) crystal plane.A non-negligible error may be introduced when the Raman data are detected on surfaces/cross-sections of different crystal planes.Owing to crystal symmetry,the mechanical,physical and optical parameters of different crystal planes show obvious anisotropy,leading to the Raman-mechanical relationship dissimilarity on the different crystal planes.In this work,a general model of stress measurement on crystalline silicon with an arbitrary crystal plane was presented based on the elastic mechanics,the lattice dynamics and the Raman selection rule.The wavenumberstress factor that is determined by the proposed method is suitable for the measured crystal plane.Detailed examples for some specific crystal planes were provided and the theoretical results were verified by experiments.

Possible Risk Factors for Severe Complications Occurring after Primary Total Knee Arthroplasty

Objective Total knee arthroplasty is one of the most common orthopedic surgeries.Readmission due to severe complications after total knee arthroplasty is a grave concern to surgeons.In this study,we evaluated the risk factors for severe complications after primary total knee arthroplasty.Methods We retrospectively collected clinical data of 2,974 patients who underwent primary total knee arthroplasty from July 2013 to June 2019 in our hospital.Postoperative complication≥gradeⅢwas defined as severe complication according to Clavien-Dindo classification system.Binary logistic regression was used to identify the predictive risk factors for severe complications.Results The complication rate after primary total knee arthroplasty was 6.8%and severe complication rate was 2.5%.Male(OR=2.178,95%CI:1.324-3.585,P=0.002),individuals above 75 years old(OR=1.936,95%CI:1.155-3.244,P=0.012),arrhythmia(OR=2.913,95%CI:1.350-6.285,P=0.006)and cerebrovascular disease(OR=2.804,95%CI:1.432-5.489,P=0.003)were predictive risk factors for severe complications after primary total knee arthroplasty.Conclusion Advanced age,male,arrhythmia,and cerebrovascular disease might be patients-related risk factors for postoperative severe complications after primary total knee arthroplasty.Special attention should be paid to patients with risk factors.

TiO2纳米粉体的掺杂改性及光催化性能研究——伯苓班无机综合实验

南开大学化学学院伯苓班本科生的无机综合实验课程中,开展"TiO2纳米粉体的掺杂改性及光催化性能研究"实验,学生自主选择掺杂元素及含量,以溶胶-凝胶方法制备不同金属及非金属掺杂的TiO2纳米粉体,采用扫描电镜、透射电镜、X射线衍射、紫外漫反射等手段表征所得材料,以甲基橙溶液模拟有机废水,研究催化剂在紫外光下的催化降解活性,选取性能最佳催化剂,测试其在模拟日光下的光解水性能。通过开展贴近科研前沿的实验内容,对伯苓班学生进行系统的科研训练,培养他们的综合科研能力。

Recurrent Myocardial Infarction and Catecholamine-Induced Cardiomyopathy:A Case Report

Pheochromocytomas or paragangliomas are rare and the diagnosis remains a challenge for clinicians.We present a woman suffering from recurrent myocardial infarction and cardiomyopathy,who was finally diagnosed with paraganglioma.Pheochromocytomas or paraganglioma should be considered in the differential diagnosis of a patient with symptoms possibly referring to acute coronary syndrome and cardiomyopathy.

Phrenic Nerve Injury Is a Differential Diagnosis of Hypoxemia after Video-Assisted Thoracoscopic Thymectomy:2 Cases Report and Literature Review

Hypoxemia after general anesthesia is not uncommon.For patients after thoracotomy,the differential diagnosis is usually difficult.Surgical,anesthetic,and patient-associated factors may contribute to postoperative hypoxemia.We described two patients who underwent videassisted thoracoscopic thymectomy and developed hypoxemia immediately after extubation.Phrenic nerve injury was suspected in both patients.One case recovered spontaneously without intervention.The second case who had been demonstrated as bilateral phrenic nerve injury after the operation was continuously on ventilator after physical therapy and respiratory training for 2 months.

An Analysis of the Role of Higher Education Opportunity Expansion in Social Stratification

With higher education entering the public’s vision,the expansion of higher education opportunities has gradually become a hot topic.The lower class is eager to achieve class mobility through this opportunity,while the upper class firmly grasps the few high-quality places in higher education.What role will the expansion of higher education opportunities plays in the overall social stratification?This paper discusses the impact of the expansion of higher education opportunities on social stratification from the upper class and the lower class.

Practice and Exploration of Online Education and Teaching during the Epidemic Situation——Taking Qingdao Teaching as an Example

The COVID-19 in now has disrupted the normal teaching schedule,but it did not stop the pace of education.Under the national call of“school suspension without suspension”.Qingdao primary school as an example,started a new learning mode of“home-schooling”,to minimum the impact of epidemic prevention and control on the teaching order.Qingdao City set the city’s famous teachers,build diacritical marks teams,create quality courses.Each school undertakes the heavy responsibility,does not show the weakness,the teacher advances the battle,displays the teacher style,discusses the new mode of online education and teaching together.

The 2-axis stress component decoupling of {100} c-Si by using oblique backscattering micro-Raman spectroscopy

With the application of strain engineering in microelectronics,complex stress states are introduced into advanced semiconductor devices.However,there is still a lack of effective metrology for the decoupling analysis of the complex stress states in semiconductor materials.This paper presents an investigation on the 2-axis stress component decoupling of{100}monocrystalline silicon(c-Si)by using oblique backscattering micro-Raman spectroscopy.A spectral-mechanical model was established,and two practicable methods for actual stress decoupling analyses were proposed.The verification experiments demonstrated the correctness and applicability of the methods proposed in this paper.

Perioperative management for parturients with pulmonary hypertension:experience with 30 consecutive cases

Pregnancy with pulmonary hypertension is considered to be associated with increased maternal and neonatal mortality.We retrospectively reviewed all parturients with pulmonary hypertension who registered at our hospital between 1999 and December 2008.We collected information about patient characteristics,including maternal age,gravida and para,pulmonary hypertension category,New York Heart Association(NYHA)functional class,pulmonary artery pressure,mode of delivery and type of anesthesia,use of anticoagulation and advanced therapy(nitric oxide,prostacyclin analogus,bosentan or sildenafil).The overall maternal mortality was 16.7%in puerperium,and there were four fetal/neonatal deaths(13%).Logistic regression could not identify any factors,including modes of anesthesia,mode of delivery,and categories and severity of pulmonary hypertension,that were significant predictors of mortality.Maternal mortality in parturients with pulmonary hypertension is high and women with pulmonary hypertension who become pregnant warrant a multidisciplinary approach.

基于角度分辨倾斜背散射拉曼光谱的单晶硅应力分量解耦分析

对于应变工程而言,应力是控制半导体器件光电性能的关键.显微拉曼光谱是一种有效的半导体材料应力无损分析技术.然而,使用传统拉曼方法得到的结果通常是特定晶体/特定晶面的面内等效应力或主应力和.本文提出了一种基于角度分辨倾斜背散射显微拉曼光谱的应力分析方法.通过在样品坐标系中求解晶格动力学方程,在特征向量坐标系中进行拉曼选择,提出了一种通用的物理力学模型.利用该模型,考虑折射率、转偏和数值孔径影响等因素,建立了任意应力状态下任意晶面(以单晶硅{100}面为例)上偏振拉曼频移与各应力分量的解析关系.验证实验表明,应力分量的分析结果与施加的应力状态非常吻合.证明了基于角度分辨倾斜背散射显微拉曼光谱的方法、模型和仪器,能够解决单晶硅特别是{100}晶面上的应力分量不能通过拉曼测量解耦的普遍问题.

Arthrogryposis multiplex congenita： classification, diagnosis, perioperative care, and anesthesia

Arthrogryposis multiplex congenita （AMC） is a rare disorder characterized by non-progressive, multiple contractures. In addition to affected extremities, patients may also present microstomia, decreased temporomandibular joint mobility. Although the etiology of AMC is unclear, any factor that decreases fetal movement is responsible for AMC. Thus, accurate diagnosis and classification are crucial to the appropriate treatment of AMC. The development of ultrasound technology has enabled prenatal diagnosis. Very early treatment is favorable, and multidisciplinary treatment is necessary to improve the function of AMC patients. Most patients require surgery to release contracture and reconstruct joints. However, perioperative care is challenging, and difficult airway is the first concern of anesthesiologists. Postoperative pulmonary complications are common and regional anesthesia is recommended for postoperative analgesia. This review on AMC is intended for anesthesiologists. Thus, we discuss the treatment and perioperative management of patients undergoing surgery, as well as the diagnosis and classification of AMC.

Concurrent adsorption and reduction of chromium(Ⅵ)to chromium(Ⅲ)using nitrogen-doped porous carbon adsorbent derived from loofah sponge

To develop highly effective adsorbents for chromium removal,a nitrogen-doped biomass-derived carbon(NHPC)was synthesized via direct carbonation of loofah sponge followed by alkali activation and doping modification.NHPC possessed a hierarchical micro-/mesoporous lamellar structure with nitrogen-containing functional groups(1.33 at%),specific surface area(1792.47 m2/g),and pore volume(1.18 cm^(3)/g).NHPC exhibited a higher Cr(Ⅵ)adsorption affinity than the HPC(without nitrogen doping)or the pristine loofah sponge carbon(LSC)did.The influence of process parameters,including pH,dosage,time,temperature,and Cr(Ⅵ)concentration,on Cr(Ⅵ)adsorption by NHPC were evaluated.The Cr(Ⅵ)adsorption kinetics matched with the pseudo-second-order model(R^(2)≥0.9983).The Cr(Ⅵ)adsorption isotherm was fitted with the Langmuir isotherm model,which indicated the maximum Cr(Ⅵ)adsorption capacities:227.27,238.10,and 285.71 mg/g at 298K,308K,and 318K,respectively.The model analysis also indicated that adsorption of Cr(Ⅵ)on NHPC was a spontaneous,endothermal,and entropy-increasing process.The Cr(Ⅵ)adsorption process potentially involved mixed reductive and adsorbed mechanism.Furthermore,computational chemistry calculations revealed that the adsorption energy between NHPC and Cr(VI)(-0.84 eV)was lower than that of HPC(-0.51 eV),suggesting that nitrogen doping could greatly enhance the interaction between NHPC and Cr(VI).

Individualized red-cell transfusion strategy for non-cardiac surgery in adults:a randomized controlled trial

Background:Red-cell transfusion is critical for surgery during the peri-operative period;however,the transfusion threshold remains controversial mainly owing to the diversity among patients.The patient’s medical status should be evaluated before making a transfusion decision.Herein,we developed an individualized transfusion strategy using the West-China-Liu’s Score based on the physiology of oxygen delivery/consumption balance and designed an open-label,multicenter,randomized clinical trial to verify whether it reduced red cell requirement as compared with that associated with restrictive and liberal strategies safely and effectively,providing valid evidence for peri-operative transfusion.Methods:Patients aged>14 years undergoing elective non-cardiac surgery with estimated blood loss>1000 mL or 20%blood volume and hemoglobin concentration<10 g/dL were randomly assigned to an individualized strategy,a restrictive strategy following China’s guideline or a liberal strategy with a transfusion threshold of hemoglobin concentration<9.5 g/dL.We evaluated two primary outcomes:the proportion of patients who received red blood cells(superiority test)and a composite of in-hospital complications and all-cause mortality by day 30(non-inferiority test).Results:We enrolled 1182 patients:379,419,and 384 received individualized,restrictive,and liberal strategies,respectively.Approximately 30.6%(116/379)of patients in the individualized strategy received a red-cell transfusion,less than 62.5%(262/419)in the restrictive strategy(absolute risk difference,31.92%;97.5%confidence interval[CI]:24.42-39.42%;odds ratio,3.78%;97.5%CI:2.70-5.30%;P<0.001),and 89.8%(345/384)in the liberal strategy(absolute risk difference,59.24%;97.5%CI:52.91-65.57%;odds ratio,20.06;97.5%CI:12.74-31.57;P<0.001).No statistically significant differences were found in the composite of in-hospital complications and mortality by day 30 among the three strategies.Conclusion:The individualized red-cell transfusion strategy using the West-China-Liu’s Score reduced red-cell transfusion without increasing in-hospital complications and mortality by day 30 when compared with restrictive and liberal strategies in elective non-cardiac surgeries.Trial registration:ClinicalTrials.gov,NCT01597232.

A critical review of on-site inorganic arsenic screening methods

Approximately 94 to 220 million people worldwide are at risk of drinking well water containing arsenic > 10 μg/L, the WHO guideline value. To identify non-compliant domestic wells, assess health risks and reduce exposure, accurate and rapid on-site inorganic arsenic screening methods are desirable because all domestic wells worldwide need to be tested.Here, the principles, advantages and limitations of commonly used colorimetry, electrochemistry, and biosensing methods are critically reviewed, with the performance compared with laboratory-based benchmark methods. Most commercial kits are based on the classic Gutzeit reaction. Despite being semi-quantitative, the more recent and more expensive products display improved and acceptable accuracy and shorter testing time (~10 min). Carried out by trained professionals, electrochemical methods are also feasible for on-site analysis, although miniaturization is desirable yet challenging. Biosensing using whole bacterial cells or bio-engineered materials such as aptamers is promising, if incorporated with function specific nanomaterials and biomaterials. Since arsenic is frequently found as arsenite in reducing groundwater and subject to oxidation during sampling, transportation and storage, on-site separation and sample preservation are feasible but the specific methods should be chosen based on sample matrix and tested before use. To eliminate arsenic exposure among hundreds of millions of mostly rural residents worldwide, we call for concerted efforts in research community and regulatory authority to develop accurate, rapid, and affordable tests for on-site screening and monitoring of arsenic in drinking water. Access to affordable testing will benefit people who are socioeconomically disadvantaged.

Influence of soy protein isolate on the gel properties of walnut protein isolate-κ-carrageenan treated with NaCl

The demand for plant protein is increasing significantly due to the shortage of protein resources.Walnut protein,the main by-product of preparing walnut oil,has limited application in the food industry due to its poor solubility.It was found that the soy protein isolate(SPI)concentration had significant effects on the gel properties of the walnut protein isolate(WNPI)-κ-Carrageenan(KC)composite system treated with 15 mmol/L NaCl.The results showed that the gel strength of the composite system increased first and then decreased with the increased concentration of SPI from 0 to 2.5%.The best rheological properties,texture properties,water holding capacity((92.03±1.05)%),swelling ratio((2.04±0.19)%),freeze-thaw stability and thermal stability(85.53°C)of the composite gel were found at an SPI concentration of 1%.In the meantime,the secondary structure of protein had the least α-helix content of 10.17% and the highest β-sheet content of 39.64%,the fluorescence intensity and free sulfhydryl content reached the highest value.1% SPI could also act as a filler for WNPI to enhance the intermolecular forces such as hydrophobic interaction between the two substances,thus forming a stable gel network structure.This study can provide technical support for improving the gel properties of walnut protein and producing new plant protein gel products.