Influence of Different Luting Agents on the Stress Distributions of Implant-supported All-ceramic Single Crown

The purpose of this study was to investigate the influence of different luting agents on the stress distribution within the crown, abutment and peri-implant bone of implant-supported all-ceramic single crown. A three-dimensional finite element model of an implant-supported single crown for the first premolar of mandible was created by COSMOS 2.85. Resin-modified glass ionomer and two different resin adhesives were used to cement the crown and abutment. Vertical 600 N and horizontal 225 N loads were applied to stimulate the condition of chewing. The stress distributions within the all-ceramic crown, abutment and peri-implant bone were analyzed. The experimental results show that the stress distributions of all-ceramic crown, abutment, implant and peri-implant bone were similar when different luting agents were used. The result of present study indicated that luting agents had no influence on the stress distributions of implant-supported all-ceramic single crown.

Injectable Biological Bulking Agent to Treat Stress Urinary Incontinence in Women: A Feasibility Pilot Study

Background: Urinary incontinence mainly affects women regardless of age and, as it affects their quality of life, influences work, sex life and independence for activities of daily living. The treatment of stress urinary incontinence including urethral volume injection therapy can provide an intermediate option over non-surgical and surgical therapies. One of the mechanisms for stress continence depends on the effective coaptation of the urethra during the increase in intra-abdominal pressure. The bulking agents can be injected transurethral or periurethral retrogradely, using direct vision from a cystoscope. Purpose: To evaluate the feasibility and preliminary outcome performance of the bacterial polysaccharide gel used as biological bulking agent applied in female patients with stress urinary incontinence. Methods: A prospective clinical pilot study was performed, in a single institution, including female patients who were admitted to the urologic outpatient clinic with Stress Urinary Incontinence (SUI) without previous treatments and they were selected and underwent bulking agent procedure. The evaluation was performed at the time of enrollment and 6 months after treatment. The primary outcome was Quality of Life (QOL) using the ICIQ-SF Questionnaire. The amount of urine leakage measured by the 1-HOUR PAD-TEST was the second outcome. Results: Fifteen women (with an average age of 53 years) were submitted to the application of bacterial cellulose gel and she was analyzed. Only two patients presented unchanged incontinence. The study considered as primary outcome the improvement or disappearance of symptoms after six months of intervention. Post-intervention Quality of Life (QOL) questionnaire indicated that all of these patients related a better quality of life (62.5%). Through the PAD-test it was possible to observe a decrease in urinary leak of 85% comparing the results pre and post-intervention (BCA—Bacterial Cellulose Application) with p-value equal to 0.000009. Conclusions: The results of this pilot study suggest that the use of biological bulking agent is a promising approach to treat stress urinary incontinence in female patients. Trial registration: Registration number and date of registration should be instated in this section.

人工草地种植策略下的草原生态变化仿真

人工草地种植是实现草地生态环境保护和牧户生活质量改善的重要途径,也是草业生产和环境治理中的重要内容之一。为了研究人工草地种植是否能达到预期的生态调节效果,该文以锡林郭勒草原的镶黄旗作为研究区域构建APG-ABM模型,模拟了五种情景下未来30年的草地发展状况,分析了牧民收入以及生态压力等指标的变化趋势。实验结果表明,未种植人工草地的情况下,牧民分别以经济效益或生态效益优先时,牧民人均收入分别在35 000元及20 000元左右,前者压力指数在[0.8,1]区间内,后者压力指数稳定在0.5以下。种植人工草地后,牧民人均收入分别达到70 000元及55 000元左右,压力指数前者在[0.7,0.9]内波动,后者稳定在0.2左右。将50%的草地资源保护后,牧民人均收入处于45 000~50 000元,生态压力处于0.5以下的正常水平。因此,人工草地的广泛种植能够使生态压力得到明显缓解,并且牧民人均收入显著提高,有利于加强中国草地生态建设。

Programmed cell death, antioxidant response and oxidative stress in wheat f lag leaves induced by chemical hybridization agent SQ-1

Male sterility induced by a chemical hybridization agent （CHA） is an important tool for utilizing crop heterosis. Leaves, especially the flag leaves, as CHA initial recipients play a decisive role in inducing male sterility. To investigate effects of different treatment times of CHA-SQ-1 used, morphological, biochemical and physiological responses of wheat flag leaves were detected in thistudy. CHA induced programmed cell death （PCD） as shown in terminal deoxynucleotidyl transferase-mediated dUTP nick end-labelling （TUNEL） and DNA laddering analysis. In the early phase, CHA-SQ-1 trig- gered organelle changes arid PCD in wheat leaves accompanied by excess production of reactive oxygen species （O2- and H202） and down-regulation of the activities of superoxide dismutase （SOD）, catalase （CAT） and guaiacol peroxidase （POD）. Meanwhile, leaf cell DNAs showed ladder-like patterns on agarose gel, indicating that CHA-SQ-1 led to the activation of the responsible endonuclease. The oxidative stress assays showed that lipid peroxidation was strongly activated and photosynthesis was obviously inhibited in SQ-l-induced leaves. However, CHA contents in wheat leaves gradually reduced along with the time CHA-SQ-1 applied. Young flags returned to an oxidative/antioxidative balance and ultimately developed into mature green leaves. These results provide explanation of the relations between PCD and anther abortion and practical application of CHA for hybrid breeding.

β成核剂对PPH拉伸双屈服行为的影响

均聚聚丙烯(PPH)广泛应用于制备餐盒和编织袋,加入β成核剂后,改善了PPH的韧性,但是,关于β成核剂对其拉伸双屈服行为影响的研究仍较少。因此,将β成核剂加入PPH熔体中,制备β⁃PPH粒料,再进行注射成型,得到样条测试其性能。将β成核剂加入PPH后,熔融曲线中出现了明显的β晶型熔融峰,随着其结晶峰值温度的升高,PPH的结晶能力得到提高,当β成核剂的含量为0.2%时,PPH中β晶型的相对含量达到最大值,其值为49.8%,断裂伸长率达到最佳;当β成核剂的添加量大于0.2%时,PPH中β晶型的相对含量逐渐降低,断裂伸长率下降。采用50 mm/min的速率进行拉伸,PPH发生高应力的双屈服行为,其第二次屈服应力值为35.53 MPa。而β⁃PPH的2次屈服应力值均较低,与β⁃PPH的第一次屈服应力值相比,其第二次屈服应力值更低,第一个屈服阶段,β⁃PPH产生应力发白现象且温度无明显变化;第二个屈服阶段,β⁃PPH产生局部颈缩且有明显温升现象。随着β成核剂含量的增大,β⁃PPH的第一次屈服应变值、第一次屈服应力值及第二次屈服应力值均减小,第二次屈服应变值增大。

水泥固化土固化机理及抗冲刷特性

为了完善水泥固化土抗冲刷性能方面的研究,使水泥固化土在水下结构防护中得到应用,在砂土和黏土中分别掺入水泥和与液体固化剂,采用土体冲刷函数测定仪(EFA)对水泥固化土开展了抗冲刷性能试验。在分析砂土和黏土的固化作用机理基础上,研究了固化剂和固化时间对水泥固化土抗冲刷性能的影响。研究结果表明:水泥固化土的强度随固化时间的增长而增大,黏土的强度快速增长阶段要早于砂土;固化剂可以有效提高土体的起动切应力,同时可以大幅减小土体的冲刷速率,明显提高了土体的抗冲刷强度;起动切应力的增长速率随固化时间增长逐渐减缓,存在临界最大值。根据起动切应力的变化特征提出了水泥固化土起动切应力预测模型,经试验数据对比,该模型可以较好地预测水泥固化土的起动切应力随固化时间的变化规律。

复合型抗盐剂对NaCl胁迫下小麦种子萌发和生长的影响

将KNO_(3)、CaCl_(2)、DA-6、KH_(2) PO_(4)、FeSO_(4)·7H_(2) O、MgSO_(4)·7H_(2) O和蔗糖7种物质组合配制复合型抗盐剂,以‘济麦22’为研究材料,采用水培法,探讨了不同浓度(0.2%、0.4%和0.6%)盐(NaCl)胁迫下,施加不同浓度(10%、20%和30%)抗盐剂对种子萌发及后续幼苗生长的影响,并提出了适合小麦的抗盐剂配方。结果表明:(1)30%、20%、10%抗盐剂分别对0.2%、0.4%、0.6%NaCl胁迫下小麦种子萌发的促进效果最好,发芽率分别提高了6.4%、12.0%、26.5%。(2)0.6%NaCl胁迫下添加抗盐剂,根干质量显著增加了29.7%~35.9%;在抗盐剂作用下,光合速率分别提高了67.5%~90.0%(0.2%NaCl胁迫)、13.3%~51.5%(0.4%NaCl胁迫)和0.4%~25.5%(0.6%NaCl胁迫),且30%抗盐剂显著增强了0.2%NaCl胁迫下小麦的光合作用,增幅达90.0%。添加抗盐剂使小麦的光合色素含量升高,其中叶绿素a在0.2%和0.4%NaCl胁迫下分别升高了22.5%~39.0%和41.7%~43.2%,叶绿素b分别升高了22.1%~31.0%和14.7%~22.5%,类胡萝卜素分别升高了12.2%~28.6%和24.4%~32.3%。此外,其他各项生理指标也有相应改善。(3)主成分分析结果显示,盐胁迫下30%抗盐剂处理后小麦的得分均为最高,为最适浓度配比。

基于Multi-agent的非常规突发事件下个体应激演化模型

为深入研究非常规突发事件下个体应激反应,为突发事件应急管理提供理论依据,基于复杂系统理论(CAS)和多主体建模方法(ABMS),构建了应激演化模型;利用NetLogo仿真平台,并根据个体所处的社会环境,动态模拟了非常规突发事件、群体、个体行为间的相互制约关系。研究表明:公众应激反应演化系统是一种复杂的自适应系统;非常规突发事件应激反应在三个不同阶段呈现出不同的特征。因此,在非常规突发事件的应急管理中,要根据个体在每个阶段不同的特征采取与之相适应的措施。

改性石墨高强调驱剂的制备及其矿场应用

采用两步改性法对石墨进行氧化改性及活性基团接枝,制备了新型改性石墨高强度调驱剂。室内实验结果表明,改性活性纳米石墨颗粒粒径在50~200 nm,具有自润滑性、易于注入、水溶分散等特点,室温稳定期可达1 a,聚结膨胀能力达常规膨胀剂的3~10倍。矿场实验表明,当质量分数为0.15%,注入量为1 PV时,综合效益最佳,且调堵、洗油性能较好,投入产出比可达1∶1.8。

预防性护理结合心理干预在行CT增强扫描患者中的应用效果

目的探讨预防性护理结合心理干预在行CT增强扫描患者中的应用效果。方法自2022年1月至2023年7月,以于南京医科大学附属苏州医院行CT增强扫描的140例患者为研究对象,按随机数字表法将其分为对照组(常规护理)和观察组(预防性护理+心理干预),各70例,比较2组的干预情况。结果检查前15 min和检查后15 min,2组的心率(HR)均快于检查前30 min,收缩压(SBP)和舒张压(DBP)均高于检查前30 min;而观察组的HR均慢于同期对照组,SBP和DBP均低于同期对照组;检查后15 min,2组的上述指标均优于检查前15 min,结果均有统计学差异(P均<0.05)。检查前30 min和检查后1 h,观察组的焦虑自评量表(SAS)评分均低于同期对照组,简化舒适状况量表(GCQ)评分均高于同期对照组,且2组均优于检查前1 d;检查后1 h,2组的上述评分均优于检查前30 min,结果均有统计学差异(P均<0.05)。观察组的造影剂外渗和不良反应总发生率均低于对照组,护理满意度评分高于对照组(P均<0.05)。结论预防性护理结合心理干预能提升行CT增强扫描患者的舒适度和护理满意度,缓解其生理应激反应和焦虑情绪,减少造影剂外渗及不良反应的发生。

考虑黏接工艺对云纹干涉钻孔法标定系数基本机理的影响

云纹干涉法与钻孔法相结合的增量钻孔技术被公认为是一种测量内部残余应力的有效方法。该技术中使用的黏接剂在试验过程中起着将应变从结构表面传递到光栅层的关键作用。然而,在求解标定系数时,往往没有考虑黏接剂的影响。基于有限元软件,从黏接剂的材料性质、粘接层的形状和尺寸、粘接层的厚度、钻孔的增量和应变测量方法5个方面考察了黏接剂对标定系数的影响。通过比较有无黏接剂时的标定系数误差,说明了黏接剂的影响。结果表明,忽略黏接剂的影响会显著影响标定系数的精度,将黏接剂从有限元模型中剔除会导致低估标定系数,标定系数的误差超过2.5%,并且与钻孔增量和测量方法有很大关系。此外,黏接剂对薄壁构件的影响比对较厚的试件更显著。

种衣剂添加黑曲霉对盐胁迫下玉米苗期生长的影响

为探究种衣剂添加黑曲霉在盐胁迫下对玉米苗期生长的影响,试验设置对照组(CK)、盐胁迫对照组(NCK)、盐胁迫施用种衣剂(NHQ)、无盐胁迫施用种衣剂(HQ)、盐胁迫施用种衣剂并添加黑曲霉(NHQ-A)、无盐胁迫施用种衣剂并添加黑曲霉(HQ-A)6个处理,结果表明,NHQ-A、HQ-A组相较NHQ、HQ组,根长分别增长16.07%和30.06%,叶宽分别增长11.08%和6.88%,叶绿素SPAD值、超氧化物歧化酶(SOD)活性、过氧化物酶(POD)活性和过氧化氢酶(CAT)活性有明显增加,丙二醛(MDA)含量下降。因此,种衣剂添加黑曲霉对玉米幼苗苗期生长具有一定的促生作用,能够缓解盐胁迫对玉米带来的一部分危害。

膨胀剂和后浇带对超长环形底板混凝土防裂的影响研究

世界上亮度最高的第四代高能同步辐射光源的超长环形底板周长约1494 m、厚1 m,如何保证底板混凝土施工质量防止裂缝产生是工程的难点。建立有限元三维数值分析模型,按照实际施工过程仿真底板混凝土的跳仓浇筑过程,模拟分析底板混凝土温度及温度应力变化情况,同时将计算温度结果与实测温度结果进行对比,验证热学参数的合理性和准确性。在反演分析基础上,研究膨胀剂和后浇带的温控防裂效果。研究结果表明:早膨胀型自变(Ⅰ型)对混凝土早龄期应力的影响是有利的,但晚膨胀型自变(Ⅲ型)的延迟膨胀性补偿由于混凝土收缩和温降引起的应力,有利于减小底板冬季最大拉应力;设置后浇带能减小底板混凝土分缝分块长度,削减混凝土最大拉应力,削减幅度为6.65%。

基于空间对抗的多智能体编队控制方法

针对3维空间对抗环境下,具有非线性二阶积分器动力学模型的多智能体系统(multi-agents system,MAS)时变编队机动与队形变换控制问题,提出一种可抑制外部干扰的MAS时变编队机动与队形变换策略。首先,根据空间对抗环境分析常见编队队形的效用,设计一种基于应力矩阵和领导跟随策略的24机编队立体构型,通过灵活地仿射变换队形,提高MAS编队空间对抗效率。其次,基于一致性理论、滑模理论和鲁棒性控制,利用时变编队应力矩阵,设计了一种鲁棒一致性跟踪控制器,以在外部未知扰动条件下,确保MAS时变编队在机动与仿射变换时跟随者对领导者的精确协同跟踪。然后,通过构造Lyapunov函数证明了外界未知扰动下3维MAS时变编队连续机动和队形变换的稳定性。最后,通过仿真实验验证了所提出的控制器能够使时变编队在机动和队形变换过程中实现精确协同跟踪。

型钢轧制动态链式模型及其智能Agent变形分析研究

冷弯型钢和焊管是广泛应用的型材,但其成型机理较难描述。针对实际冷弯成型轧制过程,为了更精准地进行应力应变分析,提出了轧制过程的动态链式模型,在样条有限条法的基础上,利用该模型研究实际轧制过程中结点与链的变形分析方法,给出链式结构结点的孔型应力应变数学描述式,并在此基础上给出了结点的智能结构。对每个结点和链建立对应的Agent,建立各Agent的知识规则,实现利用链式模型分析冷弯成型轧制过程的新方法。为建立新的复杂断面孔型设计算法提供理论基础。

Effect and Mechanism of Cold Tolerant Seed-Coating Agents on the Cold Tolerance of Early Indica Rice Seedlings

To better understand the effect and mechanism of cold tolerant seed-coating agents on the cold tolerance of rice seedlings, the physiological and biochemical effects of four cold tolerant seed-coating agents （HET, YKJ, YKZYJ, and the ABA seed coating agents） on two early indica rice varieties were studied under chilling stress. The results showed that the rice seedlings treated with cold tolerant seed-coating agents under chilling stress maintained dramatically higher root vigor, POD, CAT and SOD activities, and chlorophyll content, had lower MDA content and electrolyte leakage, and accumulated more soluble sugar and free proline, when compared with the control without the treatment, and finally showed lower plant injury rate. It was indicated that the cold tolerant seed coating agent improved the ability of rice seedlings in resisting to chilling stress. YKZYJ was ranked the first in terms of the efficiency in cold tolerance among the four cold tolerant seed-coating agents tested.

Current Techniques and Practices for Myocardial Stress Testing—A Comparative Survey between Malta and International Nuclear Medicine Centres

Objectives: The study compared cardiac scintigraphy stress scanning practices applied in a National Maltese Nuclear Medicine centre and in international centres. This was achieved through the design of an online survey which investigated participant knowledge of stress testing, and current procedural practice. Methods: An online survey comprising 12 questions was prepared using Survey Monkey. Professional Nuclear Medicine groups such as the Medical-Physics-Engineering community and Virtual Radiopharmacy were targeted. Access to the survey remained open for eight months during which a periodic reminder was sent to optimise the response rate. Forty-three members responded from across Europe and Australasia. Chi-square tests and comparisons between multiple responses using IBM SPSS 20 were used to evaluate the results. Information related to Maltese practice was collated separately for review and comparative purposes. Results: The online survey participants comprised United Kingdom [72%], other European countries [18%] and Australasia [9%]. The majority of respondents [n = 39] reported pharmacological stress testing as being performed either alone or in conjunction with exercise stress testing as the preferred option. Most participants [60%] were aware of local stress test protocols but had limited knowledge in relation to guidelines designed for cases where patients were not suitable for pharmacological stress testing. Conclusion: The survey provided information about procedures within participating centres for scintigraphic cardiac stress scanning. Differences were identified with regards to the preferred radiopharmaceutical tracers and procedural protocols. Further investigation of examination techniques is warranted, with the aim of increasing standardisation of protocol compliance and the application of more suitable practice.

Neuroprotection by immunomodulatory agents in animal models of Parkinson's disease

Parkinson’s disease（PD） is an age-related neurodegenerative disease for which the characteristic motor symptoms emerge after an extensive loss of dopamine containing neurons.The cell bodies of these neurons are present in the substantia nigra,with the nerve terminals being in the striatum.Both innate and adaptive immune responses may contribute to dopaminergic neurodegeneration and disease progression is potentially linked to these.Studies in the last twenty years have indicated an important role for neuroinflammation in PD through degeneration of the nigrostriatal dopaminergic pathway.Characteristic of neuroinflammation is the activation of brain glial cells,principally microglia and astrocytes that release various soluble factors.Many of these factors are proinflammatory and neurotoxic and harmful to nigral dopaminergic neurons.Recent studies have identified several different agents with immunomodulatory properties that protected dopaminergic neurons from degeneration and death in animal models of PD.All of the agents were effective in reducing the motor deficit and alleviating dopaminergic neurotoxicity and,when measured,preventing the decrease of dopamine upon being administered therapeutically after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine,6-hydroxydopamine,rotenone-lesioning or delivery of adeno-associated virus-α-synuclein to the ventral midbrain of animals.Some of these agents were shown to exert an anti-inflammatory action,decrease oxidative stress,and reduce lipid peroxidation products.Activation of microglia and astrocytes was also decreased,as well as infiltration of T cells into the substantia nigra.Pretreatment with fingolimod,tanshinoine I,dimethyl fumarate,thalidomide,or cocaine-and amphetamine-regulated transcript peptide as a preventive strategy ameliorated motor deficits and nigral dopaminergic neurotoxicity in brain-lesioned animals.Immunomodulatory agents could be used to treat patients with early clinical signs of the disease or potentially even prior to disease onset in those identified as having pre-disposing risk,including genetic factors.

The effect of sunblock against oxidative stress in farmers：a pilot study

Farmers are frequently exposed to ultraviolet（UV） radiation which causes various diseases by inducing oxidative stress.This study aimed to assess the effects of sunblock on oxidative stress in the body.Eighty-seven farmers were divided into two groups：those who wore sunblock for five days and those who did not.The total antioxidant capacity（TAC） in urine,which is an antioxidant indicator,and 8-hydroxy-2-deoxyguanosine（8-OHdG） levels in urine,an oxidative stress indicator,were measured.The urinary TAC of sunblock users was significantly higher than that of non-users,but urinary 8-OHdG levels were not significantly different.Even after adjustment for potential confounders,urinary TAC was found to be markedly increased with sunblock usage.These results suggest that sunblock is effective in preventing oxidative stress among farmers.In addition,they show that urinary TAC can be used as a good effect marker of oxidative stress caused by UV exposure.

Injectable treatments for female stress urinary incontinence

The use of injectable agents for the treatment of stress urinary incontinence(SUI)is an option for female patients who are unwilling to undergo surgery,or have concurrent conditions or diseases that render surgical treatment unsuitable.To be effective for SUI,an injectable agent must be nonimmunogenic,hypoallergenic,biocompatible,permanent,nonerosive,nonmigratory and painless.It must also heal with minimal fibrosis,possess a long-term bulking effect,and be easily stored and handled.Glutaraldehyde cross-linked bovine collagen(Contigen),silicone polymers(Macroplastique),Durasphere,calcium hydroxyapatite(Coaptite),polyacrylamide hydrogel(Aquamid,Bulkamid),Permacol,and stem cell therapy have been used as injectable agents.Patients must be informed that treatment with injectable agents is not as effective as surgical treatment,and that such agents might necessitate additional and repeated administrations in order to achieve the desired therapeutic effect.