细胞角蛋白20在膀胱癌中的研究进展

膀胱肿瘤是最常见的泌尿系统肿瘤,其中上皮性肿瘤占95％以上,绝大多数为尿路移行上皮细胞癌。膀胱癌的早期症状不明显,复发率较高,早期诊断和治疗对提高其疗效非常重要。近年来,诊断膀胱肿瘤的新方法不断出现,显著提高了膀胱肿瘤诊断及预后预测水平。其中,膀胱肿瘤标记物检测已成为膀胱肿瘤的诊断新方法,具有十分重要的临床意义。研究发现,细胞角蛋白20fcytokeratin20,CK20）是中间纤维家族成员之一,在正常膀胱组织中特异性表达于伞细胞,在膀胱癌中特异性表达于膀胱移行细胞癌,其诊断膀胱肿瘤的特异性和灵敏性均较高,且与膀胱肿瘤的临床分级、病理分期和转移均密切相关,因此可作为辅助诊断膀胱肿瘤的检测标志物及治疗和预后评估指标。本文将就其在膀胱癌中的研究进展综述如下。     

番茄花药培养研究进展及展望

在番茄育种中,利用花药培养产生单倍体植株,可以比常规育种方案较短时期固定和分析杂种优势的新遗传组合,建立纯合番茄品系,本文综述了国内外番茄花药培养研究概况及进展,并提供了展望。     

生态系统服务供需评估方法研究进展

生态系统服务供需评估可为识别地区均衡状况、生态权衡、生态管理、生态补偿提供依据,是生态系统服务研究的热点之一。本文收集与梳理国内外生态系统服务评估方法,将其归纳为生态模型法、价值法、参与法和经验统计模型法四大类,从供需评估角度、适用尺度范围和数据要求等方面,比较了各类方法在生态服务评估中的应用情况及优缺点。四类方法应用以评估服务供给为主,而在需求评估中的应用较少。生态模型法与价值法适用尺度范围广,涵盖从局地尺度到全球尺度,参与法与经验统计模型法则多用于中小尺度。生态模型法所需数据种类多,对数据要求高,评估精度也相对较高,在方法适用尺度、数据获取、推广应用等方面更具优势。未来生态系统服务供需评估方法研究需重点考虑以下三个方面:构建多样、标准供需指标体系,加强生态系统服务评估精确性研究,加强模型集成与开发。     

A Contact-Network-Based Formulation of a Preferential Mixing Model

Heterogeneity in the number of potentially infectious contacts and connectivity correlations (“like attaches to like” i.e., assortatively mixed or “opposites attract” i.e., disassortatively mixed) have important implications for the value of the basic reproduction ratio R ₀ and final epidemic size. In this paper, we present a contact-network-based derivation of a simple differential equation model that accounts for preferential mixing based on the number of contacts. We show that results based on this model are in good qualitative agreement with results obtained from preferential mixing models used in the context of sexually transmitted diseases (STDs). This simple model can accommodate any mixing pattern ranging from completely disassortative to completely assortative and allows the derivation of a series of analytical results.     

A new approach for designing disease intervention strategies in metapopulation models

We describe a new approach for investigating the control strategies of compartmental disease transmission models. The method rests on the construction of various alternative next-generation matrices, and makes use of the type reproduction number and the target reproduction number. A general metapopulation SIRS (susceptible–infected–recovered–susceptible) model is given to illustrate the application of the method. Such model is useful to study a wide variety of diseases where the population is distributed over geographically separated regions. Considering various control measures such as vaccination, social distancing, and travel restrictions, the procedure allows us to precisely describe in terms of the model parameters, how control methods should be implemented in the SIRS model to ensure disease elimination. In particular, we characterize cases where changing only the travel rates between the regions is sufficient to prevent an outbreak.     

温度和寄主对柑桔大实蝇化蛹进度的影响

本文在室内恒温和室外自然条件下研究了柑桔大实蝇Bactrocera minax（Enderlein）的化蛹进度,结果表明, 在恒温条件下，柑桔大实蝇的化蛹进度随饲养温度的降低而加快，低温能促进柑桔大实蝇幼虫的发育和化蛹，但相对高温饲养条件能提高蛹的质量；在自然条件下，柑桔大实蝇的化蛹进度与寄主品种（种）关系密切，早熟温州蜜柑蛆果内幼虫的化蛹进度最快，中熟温州蜜柑蛆果内幼虫次之，而纽荷尔橙蛆果内幼虫的化蛹进度最慢，但寄主品种（种）对幼虫的平均化蛹率无明显影响。      

Spatiotemporal Dynamics of Zucchini Squash Lethal Chlorosis and its Relationship with the Frankliniella zucchini Population

Lethal chlorosis of cucurbits, caused by the tospovirus Zucchini lethal chlorosis virus (ZLCV), is an important disease in the Brazilian zucchini squash crop. The virus is transmitted by the thrips Frankliniella zucchini. Progress of the disease in time and space was studied in zucchini squash experimental fields to better understand disease epidemiology. Nine independent experiments were carried out between December 2006 and September 2010. The effects of the disease were assessed every 2–7 days, depending on the experiment. The thrips population was monitored in five of these experiments. For disease progress over time, four models (exponential, monomolecular, logistic and Gompertz) were tested. Disease progress in space analysis included both the index of dispersion and Taylor's power law. The monomolecular model was the best fit to the disease incidence data, and spatial analysis indicated aggregated diseased plants at the end of the season in most experiments. A correlation was detected between the number of collected thrips and the incidence of zucchini squash lethal chlorosis. The results indicate that the thrips population significantly contributed to the primary spread of disease incidence. We propose that disease management should focus mainly on the elimination of the source of the inoculum.     

Tooth germ initiation patterns in a developing dentition: An in vivo study of Xenopus laevis tadpoles

The transparency of soft tissue in Xenopus laevis tadpoles and the anterior‐posterior orientation of their developing tooth germs in the upper jaw offer a unique opportunity for the in vivo charting of the first 15–20 days of the developing dentition. Twenty‐two X. laevis tadpoles were anesthetized daily and their mouths opened to record the first appearance, position, and development of tooth germs in the upper jaw. The initiation patterns revealed considerable variability between animals, and even between the jaw quadrants in the same animal. This variability appears within a structural boundary and the results are consistent with the presence of an odontogenic band. The final length of dental rows far exceeded the jaw growth for each quadrant during the recording period. This in vivo investigation underlines the limits of cross‐sectional studies, and in particular the assumption that tooth germs initiate at the same position in the dental row. The tooth germ initiation patterns in this study did not align with the predictions of standard models for the development of the dentition—Zahnreihen, Clone, and New Progress Zone theories.     

The asymptotic speed of propagation of the deterministic non-reducible n-type epidemic

A model has been formulated in [7] to describe the spatial spread of an epidemic involving n types of individuals, when triggered by the introduction of infectives from outside. Wave solutions for such a model have been investigated in [5] and [8] and have been shown only to exist at certain speeds. This paper establishes that the asymptotic speed of propagation, as denned in Aronson and Weinberger [1, 2], of such an epidemic is in fact c₀, the minimum speed at which wave solutions exist. This extends the known result for the one-type and host-vector epidemics.     

A sequential test for assessing the effectiveness of response strategies during an emerging epidemic

In epidemiology, the fatality rate is an important indicator of disease severity and has been used to evaluate the effects of new treatments. During an emerging epidemic with limited resources, monitoring the changes in fatality rate can also provide signals on the evaluation of government policies and healthcare quality, which helps to guide public health decision. A statistical test is developed in this paper to detect changes in fatality rate over time during the course of an emerging infectious disease. A major advantage of the proposed test is that it only requires the regularly reported numbers of deaths and recoveries, which meets the actual need as detailed surveillance data are hard to collect during the course of an emerging epidemic especially the deadly infectious diseases with large magnitude. In addition, with the sequential testing procedure, the effective measures can be detected at the earliest possible time to provide guidance to policymakers for swift action. Simulation studies showed that the proposed test performs well and is sensitive in picking up changes in the fatality rate. The test is applied to the 2014–2016 Ebola outbreak in Sierra Leone for illustration.