Modelling HIV immune response and validation with clinical data

A system of ordinary differential equations is formulated to describe the pathogenesis of HIV infection, wherein certain features that have been shown to be important by recent experimental research are incorporated in the model. These include the role of CD4+memory cells that serve as a major reservoir of latently infected cells, a critical role for T-helper cells in the generation of CD8 memory cells capable of efficient recall response, and stimulation by antigens other than HIV. A stability analysis illustrates the capability of this model in admitting multiple locally asymptotically stable (locally a.s.) off-treatment equilibria. We show that this more biologically detailed model can exhibit the phenomenon of transient viremia experienced by some patients on therapy with viral load levels suppressed below the detection limit. We also show that the loss of CD4+T-cell help in the generation of CD8+memory cells leads to larger peak values for the viral load during transient viremia. Censored clinical data is used to obtain parameter estimates. We demonstrate that using a reduced set of 16 free parameters, obtained by fixing some parameters at their population averages, the model provides reasonable fits to the patient data and, moreover, that it exhibits good predictive capability. We further show that parameter values obtained for most clinical patients do not admit multiple locally a.s off-treatment equilibria. This suggests that treatment to move from a high viral load equilibrium state to an equilibrium state with a lower (or zero) viral load is not possible for these patients.     

中国繁缕属的一些分类问题

研究了36种中国产繁缕属(Stellaria)植物,根据模式材料或仅根据原描述,将已合格发表的1组、1系、12种、4变种和1变型首次归并到有关各类,依次列举入异名录中,其中有1移属。讨论了各种错误鉴定,同时对于选择性状、设想进化过程和分布记录均有讨论。     

Numerical simulation of thermal bone necrosis during cementation of femoral prostheses

The implant of a femoral prosthesis is a critical process because of the relatively high temperature values reached at the bone/cement interface during the cementation of the infibulum. In fact, the cement is actually a polymer that polymerizes in situ generating heat. Moreover, the conversion of monomer into polymer is never 100%; this is dangerous because of the toxicity of the monomer. In this paper, we present a 3-D axisymmetric mathematical model capable of taking into account both the geometry of the implant and the chemical/physical properties of the cement. This model, together with its numerical simulation, thus represents a useful tool to set up the optimal conditions for the new materials developed in this orthopaedic field. The real complex geometry is assumed to be a bone/cement/metallic system having cylindrical symmetry, thus allowing the model to be reduced to two space variables. The cementation process is described by the Fourier heat equation coupled with a suitable polymerization kinetics. The numerical approximation is accomplished by semi-implicit finite differences in time and finite elements in space with numerical quadrature. The full discrete scheme amounts to solve linear positive definite symmetric systems preceded by an elementwise algebraic computation. We present various numerical simulations which confirm some critical aspects of this orthopaedic fixing technique such as thermal bone necrosis and the presence of unreacted residual monomer.This work was partially supported by MURST (Fondi per la Ricerca Scientifica 40%) and CNR (IAN, Contract 880032601, and Progetto Finalizzato Sistemi Informatici e Calcolo Parallelo, Sottoprogetto Calcolo Scientifico per Grandi Sistemi) of Italy     

Six things Popper would like biologists not to ignore: In memoriam, Karl Raimund Popper, 1902–1994

To honour the memory of Sir Karl Popper, I put forward six elements of his philosophy which might be of particular interest to biologists and to philosophers of biology and which I think Popper would like them not to ignore, even if they disagree with him. They are: the primacy of problems; the criticizability of metaphysics (and thus the dubiousness of materialism); how downward causation might be real; how norms should matter to scientists; why dogmatism should be avoided; how genuine science is recognizable. I preface these six things with a brief discussion of Popper's early (but later recanted) mistakes concerning biology.     

造礁石珊瑚群落结构研究的概况,问题和前景

造礁石珊瑚作为珊瑚礁生态系统中的关键生物类群,其群落结构是珊瑚礁系统研究中的一个重 要方面。本文回顾了20余年以来世界各国对造礁石珊瑚群落结构研究所取得的主要进展和认识,指出了目前研究中存在的问题并分析了不同空间范围研究结论之间的缺乏一致性和中等干扰假说的不足。 最后,结合珊瑚礁生态系统基础理论和应用发展的需求,本文探讨了造礁石珊瑚群落结构研究的前景。     

Social problems in geriatric dentistry: an overview

Many studies have reported on the dental status of elderly patients. The results demonstrate consistent differences between normative and perceived needs in addition to varying levels of awareness of dental education among carers. This review article attempts to integrate a range of social factors which must be considered if holistic and comprehensive care is to be delivered to elderly patients.     

大学课程论文教学中存在问题研究

在分析当前高校课程论文教学现状的基础上,指出其中普遍存在的问题及原因。近年来的教学改革实践表明:采取学生分组、分类指导、学生自评和教师评价相结合的方法可以有效地提高课程论文的教学效果。此外,还提出一些改进课程论文教学的合理化建议。     

铁线莲属研究随记(Ⅴ)

(1)描述了9新种,4新变种;做出了2新等级,1新组合和1新名称。(2)归并了以下拉丁学名： Clematis dioica L．ssp．virginiana(L．)Kuntze var．bahamica Kuntze,C．bahamica (Kuntze) Britton,C．orbic- ulata Correll,C．brasiliana DC．var．laxa St．Hilaire,C．perulata Kuntze,C．barranacae Jones,C．discolor Gardn., C．laxiflora Baker,C．bathiei Lévl．和C．mauritiana Lam．var．sulfurea Viguier &; Perrier。(3)对威灵仙C．chinensis Osbeck的5个变种进行了分类;特产日本的C．fujisanensis Hisauti &; Hara与C.chinensis 极为相近,主要区别在于具较大的花,但有时花与C.chinensis的花同样大,由于区别不大,在本文中被 降级作变种处理;与其近缘、具强烈退化花序、特产华东的C．anhweiensis M．C．Chang也随之被处理为 变种。(4)瑞典学者Johnson在最近出版的铁线莲属专著中将特产西印度群岛东部的C．Flukenetii DC． 归并于特产美国东南部的C．catesbyana Pursh;本文不同意他做出的归并,并列出了这两个种的明显区 别特征,确认后者是一个应该得到承认的独立的种。(5)根据墨西哥标本描述的C．acapulcensis Hook． &; Arn．原知分布于中美一带,而其在南美的居群和一小叶多毛的新变种(var．puberula)过去长期间被误 定为其近缘种C．affinis St．Hilaire;这个混乱在本文中得到澄清,同时,本文给出了这二近缘种的区别 特征。(6)Viguier和Perrier两位学者在上世纪四十年代末研究马达加斯加一带的黄花铁线莲组-怀特铁 线莲亚组(sect．Meclatis subsect．Wightianae)植物时做出了不少错误鉴定：(a)将特产马达加斯加的具三 出复叶的C．mauritiana Lam. var．mauritiana,var．coriacea和C．microcuspis Baker,以及具单叶的C．ac- tinostemmatifolia W．T．Wang均鉴定为分布于非洲大陆的C．simensis Fresen., 并将后者作为分布于亚洲和欧洲的C．orientalis L．的亚种处理;(b)将特产马达加斯加具三出复叶的C．laxiflora Baker和具一回羽状复叶的C．ibarensis Baker鉴定为特产印度南部的C．wightiana Wall.,也将后者作为C．orientalis的亚种处理;(c)将特产科摩罗(Comoros)具二回羽状复叶的C．comoresensis W．T. Wang鉴定为C．brachiata Thunb.,也将后者作为C．orientalis L．的亚种处理;(d)将C．ibarensis Baker(具一回羽状复叶和两性花)这一拉丁学名用在了另一特产马达加斯加具2～3回羽状复叶和单性花、应属于单性铁线莲组sect． Aspidanthera的种(C．rutoides W．T．Wang)之上;(e)将另一特产马达加斯加具一回羽状复叶和单性花、 也属于单性铁线莲组的C．edentata Baker(＝C．insidiosa Baill．)降级作为这两位学者曲解的C．ibarensis Baker的亚种处理;(f)将特产马达加斯加的C．dissecta Baker归并到属于茴芹叶铁线莲组(sect． Pseudanemone)的C．pimpindllifolia Hook．中。此次本文第五部分继去年第一、二部分之后对上述混乱情况做出了完全澄清,并给出了分布于马达加斯加及其邻近岛屿的怀特铁线莲亚组8种植物的检索表;由于C．ibarensis Baker的定义被上述两位学者严重误解,本文根据较多具花、果的标本写出了此种完整、正确的形态描述。     

基于潜意识理论的青少年网络成瘾研究

本文综述了青少年网络成瘾的预防和戒除方法,坚持了"习惯说",保留了对"疾病说"的看法。基于潜意识理论,将网络成瘾视为心理亚健康状态,分析了青少年网络成瘾的发生机理、提出了其预防和戒除原则。青少年网络成瘾的成因是心理上的缺失感,与青少年自我防护意识差、自我控制能力小、心理弹性弱,以及潜意识具有反复影响才可改变的特点有关。戒除网络成瘾的原则是淡化评判试测的标准、分散注意力、培养成就感、增强自信心、坚持以心治心等。     

The hybrid bacterial foraging algorithm based on many-objective optimizer

A new multi-objective optimized bacterial foraging algorithm - Hybrid Multi-Objective Optimized Bacterial Foraging Algorithm (HMOBFA) is presented in this article. The proposed algorithm combines the crossover-archives strategy and the life-cycle optimization strategy, look for the best method through research area. The crossover-archive strategy with an external archive and internal archive is assigned to different selection principles to focus on diversity and convergence separately. Additionally, according to the local landscape to satisfy population diversity and variability as well as avoiding redundant local searches, individuals can switch their states periodically throughout the colony lifecycle with the life-cycle optimization strategy. all of which may perform significantly well. The performance of the algorithm was examined with several standard criterion functions and compared with other classical multi-objective majorization methods. The examiner results show that the HMOBFA algorithm can achieve a significant enhancement in performance compare with other method and handles many-objective issues with solid complexity, convergence as well as diversity. The HMOBFA algorithm has been proven to be an excellent alternative to past methods for solving the improvement of many-objective problems.