Infection-age structured epidemic models with behavior change or treatment

We formulate infection-age structured susceptible-infective-removed (SIR) models with behavior change or treatment of infections. Individuals change their behavior or have treatment after they are infected. Using infection age as a continuous variable, and dividing infectives into discrete groups with different infection stages, respectively, we formulate a partial differential equation model and an ordinary differential equation model with behavior change or treatment. We derive explicit formulas for the reproductive number by linear stability analysis of the infection-free equilibrium, and explicit formulas for the unique endemic equilibrium, when it exists, for both models. These formulas provide mathematical theoretical frameworks for analysis of impact of behavior change or treatment of infection to the transmission dynamics of infectious diseases. We study several special cases and provide sensitivity analysis for the reproductive numbers with respect to model parameters based on those formulas.     

Ecological application of wavelet analysis in the scaling of spatial distribution patterns of Ceratoides ewersmanniana

Ecological experiments are usually conducted on small scales, but the ecological and environmental issues are usually on large scales. Hence, there is a clear need of scaling. Namely, when we deal with patterns and processes on larger scales, a special connection needs to be established on the small scales that we are familiar with. Here we presented a wavelet analysis method that could build relationships between spatial distribution patterns on different scales. With this method, we also studied how spatial heterogeneity and distribution patterns changed with the scale. We investigated the distribution and the habitat of C. ewersmanniana in two plots (200 m × 200 m; the distance between these two plots is 15 km) at Mosuowan desert. The results demonstrated that spatial heterogeneity and distribution patterns were incorporated into larger scales when the wavelet scale varied from one (5 m) to four (20 m). However, if the wavelet scale was above five (25 m), the spatial distribution patterns varied placidly, the oscillation frequency of landforms stabilized at 110 m, and the dynamic quantity period of C. ewersmanniana stabilized at 115–125 m. We also identified signal mutation points with wavelet analysis and verified the heterogeneity degree of local space with position variance. We found that position variance decomposed the distribution patterns on large scales into small sampling plots, and the position with the largest variance also had the strongest heterogeneity. In a word, the wavelet analysis method could scale-up spatial distribution patterns and habitat heterogeneity. With this method and other methods derived from this one, such as wavelet scale, wavelet variance, position variance and extremely direct-viewing graphs, wavelet analysis could be widely applied in solving the scaling problem in ecological and environmental studies.     

Availability and contributions of soil phosphorus to forage production of seeded alfalfa in semiarid Loess Plateau

The availability of soil phosphorus was studied in response to the forage production of seeded alfalfa (Medicago sativa L.), established by the ridge and furrow water-harvesting technique in the semiarid Loess Plateau of China. The following 5 treatments were set up in this study: (1) conventional cultivation in a flat plot without mulch (CK); (2) plastic mulched ridge with 30 cm width of ridge and furrow (M30); (3) plastic mulched ridge with 60 cm width of ridge and furrow (M60); (4) bare ridge with 30 cm width of ridge and furrow (B30); (5) bare ridge with 60 cm width of ridge and furrow (B60). The forage yield, evapotranspiration (ET), soil organic carbon (SOC), total phosphorus, available phosphorus and the ratio of soil organic C to available P (C/P) were measured in the experiment. Results showed that the positive correlation occurred between the decrease in soil available P and the total forage yield of alfalfa after three-year alfalfa stand. M30 and M60 were higher than those of conventional flat cultivation (CK) by 10.7% and 40.3%, respectively, whereas the yield of two bare treatments (B30 and B60) was lower than that of CK by 14.2% and 28.3%, respectively. After a 3-year alfalfa stand, the trend of the decrease in soil available P was in the order of M60 (55.5%) > M30 (51.5%) > CK (34.6%) > B30 (23.4%) > B60 (17.5%). Moreover, after 3-year alfalfa growth, the C/P ratio increased significantly in all of the treatments by comparing with that before sowing. The C/P ratios of M30 (1165.1) and M60 (1326.1) were significantly higher than those of the other treatments. More interesting finding was that the increase in SOC in dry years promoted the accumulation of soil available P. However, in wet years, the increase of SOC limited the accumulation of soil available P. Therefore, to further increase the forage yield of alfalfa, the effective technique must be developed to increase the soil available P.     

Identification of the gene imds-60 in mouse epididymis

Sperm maturation, including the acquisition of motility and the full ability to fertilize oocyte, occurs during its transit through the dynamic environment of the epididymis. However, the roles of many genes involved in the process of sperm maturation still remain to be found. Based on an expressed sequence tag named imds-60, which was first found in uterus but is highly expressed in epididymis, the full-length cDNA sequence of imds-60 with a complete open reading frame was obtained in mouse epididymis by GenBank searching, polymerase chain reaction-based procedures, and 5＇- and 3＇-rapid amplification of cDNA ends. This protein was predicted to have an N-terminal signal peptide and a C-terminal DNase I-like domain with nine transmembrane motifs in the middle part of the protein. Northern blot analysis showed that the mRNA of imds-60 was highly expressed in epididymis but at a rather lower level in uterus, seminal vesicle gland, and stomach. Further study revealed that the mRNA of imds-60 is only expressed in corpus and cauda regions of epididymis, not in caput. It is regulated partially by androgen and peaked in male mice aged from 3 weeks to adult. The imds-60 protein might play an important role in cell communication during sperm maturation.     

652例女性生殖道分泌物实验室检查结果分析

女性阴道宫颈炎是性传播疾病的主要疾病之一,临床上确切依据主要来自实验室对分泌物病原学检查,病原菌的不同,引起的疾病不同。我们对652例阴道分泌物多、臭、带色和呈奶酪状的门诊就诊患者进行了检测,现报道如下:1材料和方法1.1临床资料652例患者均为我院就诊女性,取其阴道后穹隆、宫颈分泌物。患者有不同程度的外阴瘙痒、红肿、白带增多、分泌物有异味等症状。病程最短1月,最长3年。患者年龄最小2岁,最大72岁,平均年龄32.4岁。1.2标本采集用无菌干棉签将宫颈口周围过多的黏液清除,再用无菌棉签放入阴道后穹隆及宫颈口1~2cm,轻轻旋转停留约…     

玉米T型细胞质雄性不育系与相应保持系线粒体蛋白质组中的差异蛋白

利用固相pH3—10梯度双向凝胶电泳．对玉米T型细胞质雄性不育系（T—CMS）及其相应保持系叶片（苗期、拔节期、孕穗期）,胚轴,胚根和花药（花粉母细胞减数分裂期、花粉粒小孢子单-双核期）线粒体蛋白质组中的差异蛋白进行分析。PDQuest2D图像软件分析表明,苗期和拔节期叶片约有150个蛋白质斑点,胚轴和胚根中可识别出150个线粒体蛋白质斑点,花药中约有100个斑点。利用MALDI—TOF—MS方法．运用MASCOT软件于NCBI进行数据查询．对T—CMS与相应保持系中存在的差异蛋白进行归属鉴定,在T—CMS中存在,保持系中缺失的线粒体蛋白质有：r40cl protein（胚轴中）,mature anther—specific protein,DNA—directed RNA polymerase 23kD subunit．hexokinaseⅡ和T—CMS中缺失而在保持系中存在的有：glutathione S—transferase．putative protein。其中T—CMS与相应保持系间．线粒体蛋白质组呈现出差异的组织有胚轴、胚根和小孢子单-双核期的花药。叶片的不同发育时期线粒体蛋白质组呈现明显变化．但T—CMS与保持系间没有差异。在小孢子单-双核期（花粉败育期）的花药中,T—CMS与保持系间线粒体蛋白质组出现明显差异,线粒体蛋白质组出现变异的时期与花粉败育时期相一致。     

糖尿病性视网膜病变早期mfERG的研究

目的:探讨糖尿病患者糖尿病性视网膜病变早期多焦视网膜电图(multifocal electroretinogram,mfERG)的特点。方法:应用德国ROLAND公司RETIscan系统对24例40眼糖尿病患者,同时对27例40眼正常对照眼记录mfERG。按机器的默认值一阶反应进行记录。整个记录过程中可以分为12个时段,每个时段记录为时间47秒。结果:mERG测得的糖尿病患者组1～5环所在位置的P1波的振幅密度随离心度的增加而降低,P1波和N1波幅值降低和潜伏时延迟。各象限的P1、N1波振幅密度、波幅值降低,潜伏时延迟。结论:糖尿病性视网膜病变受累的区域多发生在黄斑部,功能上的改变早于形态学的变化;病变的早期功能改变最先出现于视网膜的后极偏颞上方;糖尿病患者在未出现眼底改变时各个象限视网膜的外层已经严重受累。     

农杆菌介导的转化芦荟的研究

芦荟（Aloe）是美容和医疗保健工业的重要植物资源,然而基因工程途径改良芦荟鲜有报道。本实验研究了次氯酸钠、升汞不同浓度和时间对芦荟外植体的灭菌效果,比较了芦荟不同部位（叶片、叶鞘和茎段）的再生能力,利用GUS基因瞬间表达技术（X-Gluc染色）探讨了不同农杆菌对不同芦荟外植体的侵染效果,确定了G418筛选剂在芦荟转化后的最适筛选浓度,摸索了适宜于农杆菌—芦荟共培养用培养基组成和共培养条件,通过转化、筛选和移栽共获得了67棵抗性再生植株,进一步对抗性再生植株进行了PCR、Southern blotting和ELISA检测。结果表明,芦荟外植体灭菌方法为20.0%次氯酸钠溶液浸泡25min,效果优于利用0.1%升汞灭菌处理,茎部切段的再生能力高于叶片切段和叶鞘切段,适宜的共培养条件为芦荟外植体浸泡在含有农杆菌的液体共培养基中半小时后,在无菌滤纸上、24℃、10h光照共培养3天;EHA105农杆菌菌系对芦荟茎部细胞的侵染能力明显强于C58C1,EHA105侵染后GUS基因瞬时表达率达到了80.0%左右,而C58C1侵染后GUS基因瞬时表达率只有30.0%左右。G418用于筛选抗性再生芽和抗性植株的适宜浓度为10.0～25.0mg/L。PCR和Southern blotting检测证实外源基因已成功整合到芦荟基因组中,转化效率为0.9%,单拷贝整合占80.0%,2～3拷贝整合占20.0%,ELISA检测证明外源基因已在转基因芦荟中稳定表达。综上所述,初步建立了农杆菌介导转化芦荟的技术体系,为利用基因工程途径改良芦荟奠定了基础。     

基于MATLAB 的花粉形态量化分析

利用数字照相技术和MATLAB软件测量了5种杨树、3种柏树各50粒花粉的面积、扁圆率、极轴长度、赤道轴长度, 计算了面积标准差和极轴长度/赤道轴长度。对8种花粉的面积作了方差分析。结果显示, 在99%置信水平上用面积能区分8种花粉。用5种杨树花粉的扁圆率平均值、极轴平均值、赤道轴平均值和P/E值作聚类分析, 聚类结果显示, 5种杨树可分成3组, 加拿大杨和小叶杨是一组, 毛白杨和山杨是一组, 青杨单独为一组。电镜观察纹饰特点与以上聚类结果一致。本研究为定量研究花粉形态提供了一种快速有效的方法及更多的有效数据, 比目测精确度提高了10倍。