西安市学龄儿童年轻恒牙外伤就诊及预后的现况调查

目的了解西安市学龄儿童年轻恒牙外伤后的就诊及预后状况,探索牙外伤预后相关因素。方法采用多阶段整群随机抽样的方法,抽取西安市九区四县的小学生4 013人,对其及家长进行问卷调查,筛选有年轻恒牙外伤史的儿童作为调查对象,进行外伤情况的单独提问及口腔检查牙外伤的类型及预后,对数据进行统计分析。结果有效问卷3 641份。西安市学龄儿童年轻恒牙的外伤就诊率为38.2%,与牙外伤就诊相关的因素为性别与外伤类型,不良预后的发生率为29.7%,未就诊外伤牙的不良预后发生率(35.4%)高于就诊外伤牙(20.6%)。结论西安市学龄儿童年轻恒牙外伤就诊率较低,不良预后发生率较高。

西安市学龄儿童年轻恒牙外伤的现况调查

目的探讨西安市学龄儿童年轻恒牙外伤的患病情况、分布特征及外伤原因,为卫生行政部门的决策提供科学依据。方法采用简单随机抽样及整群抽样的方法,抽取西安市九区四县在校小学生4013人,对学生及其家长进行问卷调查,并对有年轻恒牙外伤史的学生做口腔检查,记录外伤牙的数目与牙位。结果西安市学龄儿童年轻恒牙外伤患病率为10.5%,各区县患病率无统计学差异(P>0.05);儿童年轻恒牙外伤发病高峰期是7~9岁,8岁最为多见(31.5%);最常见的牙外伤原因是跌倒(50.9%),其次是碰撞(36.0%);最常见的外伤牙是上颌中切牙(75.4%)。结论西安市儿童年轻恒牙的外伤患病率处于中位水平,对处于牙外伤年龄高发阶段的儿童应该做相应的牙外伤预防措施,以降低牙外伤的发生。

西安市学龄儿童家长牙外伤知识调查

目的:了解西安市学龄儿童家长对儿童牙外伤的认知程度,为口腔健康知识宣传教育提供参考依据。方法:采用单纯随机抽样及整群抽样的方法,抽取西安市9区4县的6~12岁在校小学生4 013人,对其家长进行问卷调查,对3 641份有效问卷进行统计分析。结果:西安市学龄儿童家长随着受教育程度的提高,认为牙外伤后需要就诊的人数比例有上升趋势;有全脱位恒牙再植意识的人群比例较低(10.1%),而对于全脱位牙齿选择较合适保存媒介的人群为48.2%。结论:西安市学龄儿童家长对牙外伤的认知程度不高,需要加强公众牙外伤知识的宣教。

大学新生社交焦虑状况与父母养育方式、人格的相关性研究

目的探讨大学新生的社交焦虑状况与父母养育方式、人格的关系。方法对240名大学新生施测交往焦虑量表、父母养育方式评价量表及艾森克人格问卷。结果大学新生的社交焦虑与父母养育方式评价量表中的父母亲的情感温暖与理解关心、EPQ中内外向呈负相关,与父母亲的拒绝和否认、父母亲的惩罚、严厉、母亲过度干涉、保护、人格中的精神质呈正相关;且父亲的拒绝和否认、母亲的情感温暖与理解关心及EPQ中的神经质和内外向进入回归方程,决定系数分别为0.08和0.19。结论父母养育方式和人格因素对大学新生的社交焦虑均有影响,但影响程度较低。

Modeling and characterization on electroplastic effect during dynamic deformation of 5182-O aluminum alloy

The coupling effects of electrical pulse,temperature,strain rate,and strain on the flow behavior and plasticity of 5182-O aluminum alloy were investigated and characterized.The isothermal tensile test and electrically-assisted isothermal tensile test were performed at the same temperature,and three typical models were further embedded in ABAQUS/Explicit for numerical simulation to illustrate the electroplastic effect.The results show that electric pulse reduces the deformation resistance but enhances the elongation greatly.The calibration accuracy of the proposed modified Lim−Huh model for highly nonlinear and coupled dynamic hardening behavior is not much improved compared to the modified Kocks−Mecking model.Moreover,the artificial neural network model is very suitable to describe the macromechenical response of materials under the coupling effect of different variables.

Insights into Reduction of CO_(2)to CO Catalyzed by Pyramidal-4Ni Clusters Supported on Doped CeO_(2)

Converting CO_(2)into valuable chemicals has become a widely used research method for CO_(2)conversion.In this work,the catalytic performance of pyramidal-4Ni catalysts supported on rare earth metal-doped CeO_(2)towardCO_(2)reductionreaction(CO_(2)RR)was investigated by using density-functional theorycalculations.For rare earth metal-doped CeO_(2),2Ce is substituted by 2 trivalent cations and at the same time one oxygen vacancy is created to make charge compensation.We investigated the oxygen vacancy nearest(Vo,N)and next-nearest(Vo,NN)to 4Ni,and found releasing CO and CO_(2)dissociation are the rate-determining steps,respectively,via the path of Vo,N and Vo,NN.Among the studied dopants(Ga,Sb,Lu,Gd,Pr,La,Bi),Gd is identified as the best dopant for catalyzing the reduction of CO_(2)at 823 K,with the turn-over frequency(TOF)of 104 times as large as that over 4Ni supported on pure CeO_(2).This exploration provides theoretical support and guidance for the research and application of rare earth metaldoped CeO_(2)-loaded Ni catalysts in the field of CO_(2)reduction.

Chalcogen heteroatoms doped nickel-nitrogen-carbon single-atom catalysts with asymmetric coordination for efficient electrochemical CO_(2) reduction

The electronic configuration of central metal atoms in single-atom catalysts(SACs)is pivotal in electrochemical CO_(2) reduction reaction(eCO_(2)RR).Herein,chalcogen heteroatoms(e.g.,S,Se,and Te)were incorporated into the symmetric nickel-nitrogen-carbon(Ni-N_(4)-C)configuration to obtain Ni-X-N_(3)-C(X:S,Se,and Te)SACs with asymmetric coordination presented for central Ni atoms.Among these obtained Ni-X-N_(3)-C(X:S,Se,and Te)SACs,Ni-Se-N_(3)-C exhibited superior eCO_(2)RR activity,with CO selectivity reaching~98% at-0.70 V versus reversible hydrogen electrode(RHE).The Zn-CO_(2) battery integrated with Ni-Se-N_(3)-C as cathode and Zn foil as anode achieved a peak power density of 1.82 mW cm^(-2) and maintained remarkable rechargeable stability over 20 h.In-situ spectral investigations and theoretical calculations demonstrated that the chalcogen heteroatoms doped into the Ni-N_(4)-C configuration would break coordination symmetry and trigger charge redistribution,and then regulate the intermediate behaviors and thermodynamic reaction pathways for eCO_(2)RR.Especially,for Ni-Se-N_(3)-C,the introduced Se atoms could significantly raise the d-band center of central Ni atoms and thus remarkably lower the energy barrier for the rate-determining step of ^(*)COOH formation,contributing to the promising eCO_(2)RR performance for high selectivity CO production by competing with hydrogen evolution reaction.

Microstructural evolution and mechanical properties of duplex-phase Ti6242 alloy treated by laser shock peening

The effects of laser shock peening(LSP)on the microstructural evolution and mechanical properties of the Ti6242 alloy,including the residual stress,surface roughness,Vickers microhardness,tensile mechanical response,and high-cycle fatigue properties,were studied.The results showed that the LSP induced residual compressive stresses on the surface and near surface of the material.The maximum surface residual compressive stress was−661 MPa,and the compressive-stress-affected depth was greater than 1000μm.The roughness and Vickers micro-hardness increased with the number of shocks,and the maximum hardness-affected depth was about 700μm after three LSP treatments.LSP enhanced the fraction of low-angle grain boundaries,changed the grain preferred orientations,and notably increased the pole density ofαphase on the near surface from 2.41 to 3.46.The surface hardness values of the LSP samples increased with the increase of the number of shocks due to work hardening,while the LSP had a limited effect on the tensile properties.The high-cycle fatigue life of the LSP-treated sample was significantly enhanced by more than 20%compared with that of the untreated sample,which was caused by the suppression of the initiation and propagation of fatigue cracks.

Research progress on the correlation between aqueous humor components and pathogenesis and postoperative complications in patients with different types of cataracts

Aqueous humor provides the necessary nutrition for the lens and transports the metabolites in the eye.It was a liquid that can directly reflect the microenvironment in the eye'and it can be easily obtained during the operation.This review intended to analyze the components of aqueous humor in patients with different types of cataracts'so as to reflect the pathogenesis and development of the disease'evaluate the incidence of postoperative complications and provide reference value for the surgical design of sequential cataract surgery.The aqueous humor components of different types of cataracts showed different degrees of inflammation'oxidative stress and extracellular matrix remodeling.The biomarker of early neuropathy in diabetic cataract was neural cell adhesion molecule-1(NCAM1).Transforming growth factor-β(TGF-β)was the evaluation factor of disease development in patients with pseudoexfoliation syndrome.The relationships between postoperative complications of different types of cataracts and aqueous humor components were as follows:Macular edema after diabetic cataract surgery was associated with tumor necrosis factor-alpha;capsular contraction after high myopic cataract surgery was related to monocyte chemoattractant protein-1(MCP-1)and TGF-β2;Klotho and glutathione S-transferase P 1(GSTP1)were associated with high intraocular pressure after primary open-angle glaucoma complicated by cataract surgery;capsular contraction after retinitis pigmentosa complicated by cataract surgery was associated with matrix metalloproteinases;pro-inflammatory cytokines and fibroblast growth factor 4 in the aqueous humor of congenital cataracts were associated with posterior capsular opacification after surgery.Granulocyte colony stimulating factor 3 and MCP-1 were the main cytokines mediating the pain of the second eye in the binocular sequential cataract surgery short interval(1 wk)'while MCP-1 mediated pain in the long interval(6 wk).The second eye after binocular sequential cataract surgery had a higher level of proinflammatory factors.The components of aqueous humor in patients with different types of cataracts were related to the pathogenesis and postoperative complications of the disease.Monitoring the components of the aqueous humor could help better understand the intraocular microenvironment of different types of cataracts and provide a reference for predicting the development of the disease and implementing relevant targeted therapy.

Chest CT quantitative parameters in patients with acute exacerbation of chronic obstructive pulmonary disease:Correlations with blood eosinophil level

Objective To observe the correlations of chest CT quantitative parameters in patients with acute exacerbation of chronic obstructive pulmonary disease(AECOPD)with blood eosinophil(EOS)level.Methods Chest CT data of 162 AECOPD patients with elevated eosinophils were retrospectively analyzed.The patients were divided into low EOS group(n=105)and high EOS group(n=57)according to the absolute counting of blood EOS.The quantitative CT parameters,including the number of whole lung bronchi and the volume of blood vessels,low-attenuation area percentage(LAA%)of whole lung,of left/right lung and each lobe of lung,as well as the luminal diameter(LD),wall thickness(WT),wall area(WA)and WA percentage of total bronchial cross-section(WA%)of grade 3 to 8 bronchi were compared between groups.Spearman correlations were performed to analyze the correlations of quantitative CT parameters with blood EOS level.Results LAA%of the whole lung,of the left/right lung and each lobe of lung,as well as of the upper lobe of right lung LD grade 4,middle lobe of right lung WT grade 5,upper lobe of right lung WA grade 4,middle lobe of right lung WA grade 5 and lower lobe of left lung WA grade 3 in low EOS group were all higher than those in high EOS group(all P<0.05).Except for the upper lobe of right lung LD grade 4,the above quantitative CT indexes being significant different between groups were all weakly and negatively correlated with blood EOS level(r=-0.335 to-0.164,all P<0.05).Conclusion Chest CT quantitative parameters of AECOPD patients were correlated with blood EOS level,among which LAA%,a part of WT and WA were all weakly negatively correlated with blood EOS level.

Research and development on mechanism of removal of indoor volatile organic compounds by plants

Background,aim,and scope Owing to the rapid development of modernisation and urbanisation,living standards have gradually improved.However,the widespread use of high-energy-consuming indoor appliances and furniture has made indoor environments a primary environmental problem affecting human health.Sick building syndrome(SBS)and building-related illness(BRI)have occurred,and indoor air conditions have been extensively studied.Common indoor pollutants include CO,CO_(2),volatile organic compounds(VOCs)(such as the formaldehyde and benzene series),NOx(NO and NO_(2)),and polycyclic aromatic hydrocarbons(PAHs).VOCs have replaced SO_(2)as the“The Fourteenth Five-Year Plan”urban air quality assessment new indicators.Indoor VOCs can cause diseases such as cataract,asthma,and lung cancer.To protect human health,researchers have proposed several indoor air purification technologies,including adsorption,filtration,electrostatic dust removal,ozonation,and plant purification.However,each technology has drawbacks,such as high operating costs,high energy consumption,and the generation of secondary waste or toxic substances.Plant degradation of VOCs as a bioremediation technology has the characteristics of low cost,high efficiency,and sustainability,thereby becoming a potential green solution for improving indoor air quality.This study introduces the research status and mechanism of plant removal of indoor VOCs and provides an experimental basis and scientific guidance for analysing the mechanism of plant degradation of pollutants.Materials and methods This study reviews studies on the harm caused by indoor pollutants to human health and related sources,mainly investigating the degradation of indoor formaldehyde,BTEX(benzene,toluene,ethylbenzene,and xylene)plant mechanisms,and research results.Results Plants can remove VOCs via stomatal and non-stomatal adsorption,interfoliar microbial,rhizosphere microbial,and growth media.Benzene,toluene,and xylene(BTX)are adsorbed by pores,hydroxylated into fumaric acid,and then removed into CO_(2) and H_(2)O by TCA.Formaldehyde enters plant leaves through the stomata and epidermal waxy substances and is adsorbed.After the two steps of enzymatic oxidation,formic acid and CO_(2) are generated.Finally,it enters the Calvin cycle and removes glucose and other nontoxic compounds.Discussion The non-stomatal degradation of VOCs can be divided into adsorption by cuticular wax and active adsorption by plant surface microorganisms.The leaf epidermal waxy matter content and the lipid composition of the epidermal membrane covering the plant surface play important roles in the non-stomatal adsorption of indoor air pollutants.The leaf margin of a plant is an ecological environment containing various microbial communities.The endophytic and inoculated microbiota in plant buds and leaves can remove VOCs(formaldehyde and BTEX).Formaldehyde can be directly absorbed by plant leaves and converted into organic acids,sugars,CO_(2) and H_(2)O by microbes.Bioremediation of indoor VOCs is usually inefficient,leading to plant toxicity or residual chemical substance volatilisation through leaves,followed by secondary pollution.Therefore,plants must be inoculated with microorganisms to improve the efficiency of plant degradation of VOCs.However,the effectiveness of interfoliar microbial removal remains largely unknown and several microorganisms are not culturable.Therefore,methods for collecting,identifying,and culturing microorganisms must be developed.As the leaf space is a relatively unstable environment,the degradation of VOCs by rhizosphere microorganisms is equally important,and formaldehyde is absorbed more by rhizosphere microorganisms at night.The inoculation of bacteria into the rhizosphere improves the efficiency of plants in degrading VOCs.However,most of these studies were conducted in simulation chambers.To ensure the authenticity of these conclusions,the ability of plants to remove indoor air pollutants must be further verified in real situations.Conclusions Plant purification is an economical,environment-friendly,and sustainable remediation technology.This review summarises the mechanisms of VOC plant degradation and presents its limitations.Simultaneously,it briefly puts forward a plant selection scheme according to different temperatures,light,and specific VOCs that can be absorbed to choose the appropriate plant species.However,some studies have denied the purification effect of plants and proposed that numerous plants are required to achieve indoor ventilation effects.Therefore,determining the ability of plants to remove indoor VOCs requires a combination of realistic and simulated scenarios.Recommendations and perspectives Plants and related microorganisms play an important role in improving indoor air quality,therefore,the effect of plants and the related microorganisms on improving indoor air quality must be studied further and the effect of plants on indoor VOCs will be the focus of future research.

干法压裂技术在实施中的经济分析

干法压裂采用了无水无伤害性液体CO2作为挟砂剂,避免了对地层渗透率的负面影响,无需担心对地层的潜在伤害。其中CO2在泵入过程中为液态,可以携带砂子,而在返排的过程中完全气化,不会在地层中造成水或其它化学有害物质的遗留,所以干法压裂特别适合于低渗水敏储层的开发,但是由于干法压裂过程中的费用较大,而且所用二氧化碳量大,其压裂投资大于氮气压裂和氮气泡沫压裂工艺。文章对干法压裂、氮气压裂和氮气泡沫压裂三者之间在开发低渗水敏气层时的净现值进行了比较,研究结果表明,虽然干法压裂初期投资较大,但由于干法压裂可提高通流能力,产量高,且井维护费用较低,使干法压裂比另外两者的经济性更高。从压裂完成后5年内的产量可以看出,实施干法压裂的井累积产量依然是最高的,分别为N2气压裂、N2泡沫压裂累积产量的2倍和4倍。

RS/6000机群系统中分子动力学并行算法的研究

在IBM RS/6000工作站组成的机群系统和PVM（并行虚拟机）并行环境中,用消息传递机制方式和C++语言实现了微正则系综（NVE）的分子动力学并行计算程序,并对不同分子数（256～108000）组成的Lennard-jones理想流体进行了模拟研究。结果表明,在小型机群系统中,原子分解法具有理想的加速比,考虑到区域分解法的适用范围有限且实现困难,困此认为原子分解法是小型机群系统进行分子动力学并行模拟计算的理想选择。

SIS镁合金可吸收胆管支架治疗恶性梗阻性黄疸疗效分析

目的分析SIS镁合金可吸收胆管支架治疗恶性梗阻性黄疸的临床疗效。方法选取67例接受胆道金属支架引流术(EBMSD)的恶性梗阻性黄疸患者,按照置入不同金属支架分为对照组和实验组,对照组患者置入普通镍钛合金支架,实验组患者置入SIS镁合金可吸收支架。检测两组患者术前1周及术后1周血清总胆红素(TBIL)、丙氨酸转氨酶(ALT)、碱性磷酸酶(ALP)、天门冬氨酸氨基转移酶(AST)、直接胆红素(DBIL)和间接胆红素(IBIL),观察两组患者术后并发症情况及两组患者6个月生存率和引流通畅率。结果对照组插管成功率为91.7%,实验组患者插管成功率为93.5%,两组对比无明显差异(P>0.05);两组患者术后1周肝功能指标(TBIL,ALT,ALP,AST,DBIL,IBIL)明显优于术前1周(P<0.05),但两组之间术后1周肝功能指标对比无明显差异(P>0.05);实验组患者术后并发症明显低于对照组患者(P<0.05);实验组患者6个月生存率为82.3%,引流通畅率为72.4%,明显优于对照组患者的66.7%和39.4%(P<0.05)。结论 SIS镁合金可吸收胆管支架能有效缓解患者恶性梗阻性黄疸症状,改善肝功能,延长患者生存期;术后并发症低于普通镍钛合金支架。

个性化重建板辅助游离腓骨重建上颌骨半侧缺损的优化设计

目的:利用CAD/CAM以及3D打印技术体外辅助游离腓骨瓣重建上颌骨半侧缺损。方法:利用CAD/CAM建立游离腓骨瓣重建上颌骨半侧缺损的三维模型,设计个性化重建板、截骨导板辅助重建完成,通过3D打印技术生成术前模型、截骨导板以及重建板,模型外科模拟手术。采用SPSS18.0软件包对数据进行统计学分析。结果:快速建立了3段式游离腓骨重建上颌骨缺损的数字化模型,并设计生成原发灶截骨导板和重建辅助个性化重建板。定点测量显示,模型外科模拟重建精度与计算机模拟无显著差异(P>0.05)。结论:优化设计的辅助措施和个性化重建板可以增加游离腓骨重建上颌骨缺损的准确性,有助于临床上精确外科重建。

采用离子电流法的甲醇发动机失火诊断

在一台由四缸柴油机改装而成的甲醇发动机上,采用以火花塞作为传感器的离子电流测量法在线获得了发动机正常燃烧和3种典型失火工况时的离子电流信号,分析了它们之间的异同,给出了3种典型失火工况的离子电流信号特征值,并利用离子电流的焰后区峰值幅值及峰值位置量化了试验用甲醇发动机发生失火的判定依据。结果表明:当发动机正常燃烧时,离子电流曲线只含有前锋区和焰后区;当火焰不能连续传播而引起失火时,离子电流信号在上止点附近出现若干尖峰;当断油引起失火时,离子电流只出现点火信号;当缓慢燃烧引起失火时,离子电流波形分别在前锋区和焰后区出现峰值。该结果可为离子电流法在点燃式甲醇发动机中的应用提供理论依据。

迟发性运动障碍的相关问题回顾

作者参阅国内外有关迟发性运动障碍 (简称 TD)的相关文献 ,重点阐述了 TD发病的危险因素、TD的发病机制以及

多媒体辅助的医患交流方式对口腔印模前信息交流效果的影响

目的:研究在制取口腔印模前,多媒体辅助的医患信息交流方式对患者理解程度的影响。方法:将符合纳入标准的120名患者随机分为对照组、视频组、图片组三组:对照组采用统一录制的音频资料向患者讲解口腔印模的相关知识;视频组和图片组在同样音频资料的基础上,分别采用视频或图片向患者传递口腔印模相关知识。利用问卷作答及印模制取过程中患者的行为评估得分对实验效果进行定量分析,并通过电话随访对患者的认可度进行调查。结果采用SPSS19.0软件对计量资料进行K-W检验,检验水准α=0.05。结果:视频和图片组中各有97.5%和87.5%的患者认为自己所接受的沟通方式良好,而对照组中只有42.5%的患者持同样看法。视频组的问卷及行为评估得分均显著高于其他两组(P<0.05),图片组的问卷得分优于对照组(P<0.05),但行为评估结果显示两组间差异无统计学意义(P>0.05)。结论:多媒体辅助的医患信息交流方式可促进患者对口腔印模的理解程度,增强信息传递的有效性,值得在临床工作中推广。

城市与农村中学生自我概念的比较研究

目的 比较城市与农村中学生自我概念的状况。方法 采用 Piers-Harris儿童自我概念量表 ,对 362名初一至高二的城市、农村中学生进行调查。结果 城市学生在智力、外貌、焦虑。