A Damage Model of Concrete including Hysteretic Effect under Cyclic Loading

A novel damage model for concrete has been developed, which can reflect the complex hysteresis phenomena of concrete under cyclic loading, as well as other nonlinear behaviors such as stress softening, stiffness degradation, and irreversible deformation. The model cleverly transforms the complex multiaxial stress state into a uniaxial state by equivalent strain, with few computational parameters and simple mathematical expression. The uniaxial tensile and compressive stress–strain curves matching the actual characteristics are used to accommodate the high asymmetry of concrete in tension and compression, respectively. Meanwhile, an unloading path and a reloading path that can reflect the hysteresis effect under cyclic loading of concrete are established, in which the adopted expressions for the loading and unloading characteristic points do not depend on the shape of the curve. The proposed model has a concise form that can be easily implemented and also shows strong generality and flexibility. Finally, the reliability and correctness of the model are verified by comparing the numerical results with the three-point bending beam test, cyclic loading test, and a seismic damage simulation of the Koyna gravity dam.     

Recombinant Bovine Herpesvirus Type I Expressing the Bovine Viral Diarrhea Virus E2 Protein Could Effectively Prevent Infection by Two Viruses

Bovine respiratory disease complex (BRDC) is a comprehensive disease in cattle caused by various viral and bacterial infections. Among them, bovine herpesvirus type I (BoHV−1) and bovine viral diarrhea virus (BVDV) play important roles and have caused huge financial losses for the cattle industry worldwide. At present, vaccines against BRDC include trivalent attenuated BoHV−1, BVDV−1, and BVDV−2 live vaccines, BoHV−1 live attenuated vaccines, and BoHV−1/BVDV bivalent live attenuated vaccines, which have limitations in terms of their safety and efficacy. To solve these problems, we optimized the codon of the BVDV−1 E2 gene, added the signal peptide sequence of the BoHV−1 gD gene, expressed double BVDV−1 E2 glycoproteins in tandem at the BoHV−1 gE gene site, and constructed a BoHV−1 genetics-engineered vectored vaccine with gE gene deletion, named BoHV−1 gE/E2−Linker−E2⁺ and BoHV−1 ΔgE. This study compared the protective effects in BoHV−1, BoHV−1 ΔgE, BoHV−1 gE/E2−Linker−E2⁺, and BVDV−1 inactivated antigen immunized guinea pigs and calves. The results showed that BoHV−1 gE/E2−Linker−E2⁺ could successfully induce guinea pigs and calves to produce specific neutralizing antibodies against BVDV−1. In addition, after BoHV−1 and BVDV−1 challenges, BoHV−1 gE/E2−Linker−E2⁺ can produce a specific neutralizing antibody response against BoHV−1 and BVDV−1 infections. Calves immunized with this type of virus can be distinguished as either vaccinated animals (gE^-) or naturally infected animals (gE⁺). In summary, our data suggest that BoHV−1 gE/E2−Linker−E2⁺ and BoHV−1 ΔgE have great potential to prevent BVDV−1 or BoHV−1 infection.     

Establishment of an optimized CTC detection model consisting of EpCAM,MUC1 and WT1 in epithelial ovarian cancer and its correlation with clinical characteristics

Objective: Emerging studies have demonstrated the promising clinical value of circulating tumor cells(CTCs)for diagnosis, disease assessment, treatment monitoring and prognosis in epithelial ovarian cancer. However, the clinical application of CTC remains restricted due to diverse detection techniques with variable sensitivity and specificity and a lack of common standards.Methods: We enrolled 160 patients with epithelial ovarian cancer as the experimental group, and 90 patients including 50 pat...     

肺结节与肺癌全程智能管理云平台的构建及临床应用

目的 我国肺癌患病率、病死率稳居恶性肿瘤第一位。创建肺结节与肺癌全程管理模式,将肺结节纳入规范诊疗体系,以期实现肺癌早诊早治,提高患者复诊依从性。方法 构建肺结节与肺癌全程智能管理云平台,建立恶性肺结节队列、良性肺结节队列和未确诊肺结节规律随访队列。收集人口统计学、影像、病理、疗效等信息,通过全程管理后分析人群特征、诊治精准性与复诊率。结果 创建了基于重庆市肺结节管理工作室的肺结节与肺癌全程智能管理云平台。2019年1月至2021年12月期间,纳入全程管理的肺结节与肺癌患者共5 144例,确诊肺结节1 546例(30.05%),其中恶性1 194例,良性352例;Ia期肺癌占确诊肺癌的(80.80%);随访中肺结节3 598例(69.95%)。2019年进入平台登记管理后未确诊的肺结节,有≥1次复诊记录的患者652例(74.86%);2020年667例(65.67%);2021年245例(13.94%)。结论 建立肺结节与肺癌全程智能管理云平台有利于提高恶性肺结节早诊早治率与患者依从性,促进患者自我健康管理模式养成,改善肺癌预后,值得尝试。     

乳突后小骨窗开颅骨片复位显微手术切除大型桥小脑角肿瘤

目的 探讨大型桥小脑角肿瘤经乳突后小骨窗开颅、骨片复位的手术方法 及其治疗效果.方法 18例大型桥小脑角肿瘤(听神经鞘瘤13例,脑膜瘤3例,胆脂瘤2例)均采用单侧乳突后小骨窗开颅,应用显微神经外科技术进行肿瘤切除,必要时磨开内听道,术中行脑干听觉诱发电位(BAEP)、体感诱发电位(SEP)和面神经功能监测,肿瘤切除后严密缝合硬脑膜,骨片复位.结果 肿瘤全切除17例、次全切除1例.全组患者的面神经均得到了解剖保留.无手术死亡.术后复查MRI示17例肿瘤全切除者未见有肿瘤残留,1例听神经鞘瘤行次全切除者于内听道内可见少许肿瘤组织残留,术后3个月行伽玛刀治疗.术后有10例遗留轻度面瘫(口角稍有歪斜,眼睑闭合良好),均为大型听神经鞘瘤患者,余患者无脑神经功能障碍,恢复良好.结论乳突后小骨窗开颅术适用于不同大小的桥小脑角肿瘤,严格按显微神经外科技术操作,结合术中BAEP,SEP和面神经功能监测,均可做到肿瘤全切除,并能有效地保护肿瘤周围的重要神经结构及其功能.严密缝合硬脑膜和骨片复位可消除局部皮下积液.     

Biofluid Biomarkers of Alzheimer’s Disease: Progress,Problems, and Perspectives

Since the establishment of the biomarker-based A-T-N (Amyloid/Tau/Neurodegeneration) framework in Alzheimer’s disease (AD), the diagnosis of AD has become more precise, and cerebrospinal fluid tests and positron emission tomography examinations based on this framework have become widely accepted. However, the A-T-N framework does not encompass the whole spectrum of AD pathologies, and problems with invasiveness and high cost limit the application of the above diagnostic methods aimed at the central nervous system. Therefore, we suggest the addition of an “X” to the A-T-N framework and a focus on peripheral biomarkers in the diagnosis of AD. In this review, we retrospectively describe the recent progress in biomarkers based on the A-T-N-X framework, analyze the problems, and present our perspectives on the diagnosis of AD.     

补体C3a受体1与低级别胶质瘤预后及免疫细胞浸润的关系

目的 借助癌症基因组图谱(TCGA)数据库研究低级别胶质瘤(LGG)组织中补体C3a受体1(C3AR1)的表达水平及其与LGG患者预后及肿瘤免疫细胞浸润的关系.方法 从TCGA数据库下载514例LGG患者的基因表达谱数据和临床信息.比较C3AR1基因在LGG组织和正常组织中的表达水平,分析不同WHO分级LGG组织样本中...     

Reimagining Undergraduate Medical Education in a Post-COVID-19 Landscape

Online education due to the COVID-19 pandemic caused many medical schools to increasingly employ asynchronous and virtual learning that favored student independence and flexibility. At the same time, the COVID-19 pandemic highlighted existing shortcomings of the healthcare field in providing for marginalized and underserved communities. This perspective piece details the authors’ opinions as medical students and medical educators on how to leverage the aspects of pandemic medical education to train physicians who can better address these needs.KEY WORDS: undergraduate medical education, social determinants of health, virtual learning

“American medical education needed a revolution,” writes Professor Jon M. Barry in The Great Influenza: The Story of the Deadliest Pandemic in History¹. He described a different era of medical education, a time in the late 1800s when medical students graduated without having ever touched a patient. The revolution began at Johns Hopkins Hospital with William Osler’s teaching hospital model for postgraduate training, a model that spread across the nation and has formed the foundation for modern medical education². A few decades later, the Flexner Report commissioned by the American Medical Association codified recommendations for standardized curriculum based on Osler’s program at Hopkins, giving rise to the biomedical model of medical education^{3, 4}. In the same decade, the 1918 influenza pandemic, one of the deadliest pandemics in the history of humankind, infected approximately one-third of the world’s population, causing an estimated 50 million deaths⁵. Clearly, as Barry describes, it was a time of great crisis, ripe for great change.The Flexner Report and 1918 pandemic thus led to many medical schools adopting the biomedical model and overhauling their curricula. Since then, shortcomings of the Flexner Report, such as limiting the opportunities of Black physicians and excluding social determinants of health from the medical model^{4, 6}, have been acknowledged and medical education has increasingly prioritized diversity and inclusion and public health education to better serve the diverse health needs of society^7–9. The biopsychosocial model of medicine has largely supplanted the biomedical model^{7, 8}, and many medical schools have modified their biomedical curricula to incorporate systems-based learning and social determinants of health.Yet healthcare is far from perfect today, with issues of cost, access, and systemic inequality still plaguing patients. As medical students and medical educators, we strive for a medical education that will better prepare the next generation of physicians to address these failures of the profession. We also have experienced how the current COVID-19 pandemic, similar to the 1918 influenza pandemic, has caused great crises in healthcare and changes in medical education^10–12. As vaccines have made a post-COVID era more tangible, we believe the medical field is once again ripe for revolution. In this perspective piece, we detail how we can leverage the current flux in medical education, capitalizing on asynchronous and virtual learning with a focus on social determinants and disparities, to better train physicians who will be prepared to serve the public health in a post-COVID era.