稻田生物群落的能流参数

为了从能流动态来研究稻田生物群落,本文用田间调查和实验室测定等方法,取得了晚稻田生物群落的物种数量、生物量、热值、呼吸量、生产力、同化效率、摄食量等数据。据此,进一步估算了晚稻田生物群落的能量流动参数。根据其能量收支,用能量金字塔总结了晚稻田生物群落各类种群间的能量关系。     

On evaluation of infection probabilities for different age groups

It is well known that evaluation of parameters for any mathematical model is always very important and often a very difficult problem. This is especially true for agents-based models because as a rule the evaluation of an agent's parameters can be made only based on available information from the higher levels of a complex system. Such problems can be ill-posed or even have a non-unique solution. That is why there is no general algorithm for solving these problems and a researcher has to search for it for every specific model type.     

Structural changes in a binary mixed phospholipid bilayer of DOPG and DOPS upon saposin C interaction at acidic pH utilizing P and H solid-state NMR spectroscopy

Saposin C (Sap C) is known to stimulate the catalytic activity of the lysosomal enzyme glucosylceramidase (GCase) that facilitates the hydrolysis of glucosylceramide to ceramide and glucose. Both Sap C and acidic phospholipids are required for full activity of GCase. In order to better understand this interaction, mixed bilayer samples prepared from dioleoylphosphatidylglycerol (DOPG) and dioleoylphosphatidylserine (DOPS) (5:3 ratio) and Sap C were investigated using ²H and ³¹P solid-state NMR spectroscopy at temperatures ranging from 25 to 50 °C at pH 4.7. The Sap C concentrations used to carry out these experiments were 0 mol%, 1 mol% and 3 mol% with respect to the phospholipids. The molecular order parameters (S_CD) were calculated from the dePaked ²H solid-state NMR spectra of Distearoyl-d70-phosphatidylglycerol (DSPG-d70) incorporated with DOPG and DOPS binary mixed bilayers. The S_CD profiles indicate that the addition of Sap C to the negatively charged phospholipids is concentration dependent. S_CD profiles of 1 mol% of the Sap C protein show only a very slight decrease in the acyl chain order. However, the S_CD profiles of the 3 mol% of Sap C protein indicate that the interaction is predominantly increasing the disorder in the first half of the acyl chain near the head group (C1-C8) indicating that the amino and the carboxyl termini of Sap C are not inserting deep into the DOPG and DOPS mixed bilayers. The ³¹P solid-state NMR spectra show that the chemical shift anisotropy (CSA) for both phospholipids decrease and the spectral broadening increases upon addition of Sap C to the mixed bilayers. The data indicate that Sap C interacts similarly with the head groups of both acidic phospholipids and that Sap C has no preference to DOPS over DOPG. Moreover, our solid-state NMR spectroscopic data agree with the structural model previously proposed in the literature [X. Qi, G.A. Grabowski, Differential membrane interactions of saposins A and C. Implication for the functional specificity, J. Biol. Chem. 276 (2001) 27010-27017] [1].     

Causal inference in biomolecular pathways using a Bayesian network approach and an Implicit method

We introduce here the concept of Implicit networks which provide, like Bayesian networks, a graphical modelling framework that encodes the joint probability distribution for a set of random variables within a directed acyclic graph. We show that Implicit networks, when used in conjunction with appropriate statistical techniques, are very attractive for their ability to understand and analyze biological data. Particularly, we consider here the use of Implicit networks for causal inference in biomolecular pathways. In such pathways, an Implicit network encodes dependencies among variables (proteins, genes), can be trained to learn causal relationships (regulation, interaction) between them and then used to predict the biological response given the status of some key proteins or genes in the network. We show that Implicit networks offer efficient methodologies for learning from observations without prior knowledge and thus provide a good alternative to classical inference in Bayesian networks when priors are missing. We illustrate our approach by an application to simulated data for a simplified signal transduction pathway of the epidermal growth factor receptor (EGFR) protein.     

松毛虫狭颊寄蝇实验种群生态学研究

松毛虫狭颊寄蝇(Carcelia matsukarehae)是松毛虫重要的寄生天敌之一,在控制松毛虫自然种群增长中起重要的作用.本文在15℃、18℃、22℃、25℃、29℃、32℃6个恒温,相对湿度为70%～85%,光照为12:12(L:D)的条件下研究了松毛虫狭颊寄蝇的生态学特性.结果表明,松毛虫狭颊寄蝇的世代发育起点温度是5.23℃,积温为523.73日·度,成虫寿命在没有补充营养的条件下为1.3～8.06d,喂以30%蜜糖水,寿命可以从9.63d延长到36.42d,成虫产卵的最适温度为23.6℃,每雌最大产量为86粒.种群增长最适温度22～25℃.以近似方法计算22℃和25℃下实验种群繁殖特征生命表参数,在22℃,R₀、T₀、r_c和λ值分别为24.89、37.33、0.086和1.089,在25℃时分别为20.01、32.38、0.09和1.10.22℃时种群最大L_xM_x出现在成虫羽化后第33～38天,25℃时的LxMx最大值出现在成虫羽化后第29～34天.     

Biological Rhythms of Biochemical Serum Parameters in a Brazilian Population: a Three‐Year Study

A marked decrease in analytical and post‐analytical variability has been achieved in clinical laboratories by the use of automated analytical systems. Current studies are now focused on the origin of pre‐analytical variability, such as that due to intra‐individual differences and biological rhythms. The objective of this work was to evaluate the occurrence of biological rhythms in several biochemical serum parameters in a Brazilian population. A retrospective study (1996 to 1998) was carried out to collect the test results within the reference intervals of adults, from 21 to 50 yr of age (average age of 36 yr) attending the outpatient clinics of the Teaching Hospital at the University of Campinas, São Paulo, Brazil. The reference sample was 52.9% male and 47.1% female and encompassed 15,036 calcium, 7,478 phosphorus, 53,641 urea, 58,315 creatinine and 6,433 uric acid determinations (140,903 in total). Significant annual rhythms were detected in serum calcium (p≤0.001), with maximum and minimum values in fall and spring, and in serum creatinine (p≤0.002), with maximum and minimum values in summer and winter. The other parameters did not present significant annual rhythmicity. The seasonal rhythms present in the serum concentrations of calcium and creatinine observed in this large population study, although of small amplitude, should be considered a component of the pre‐analytical variation of these clinical laboratory tests.     

Assessment of the functional response parameters of Coccinella septempunctata to varying densities of Acyrthosiphon pisum

The functional response of a predator describes the rate at which it kills its prey at different prey densities and is, therefore, an important tool to determine the efficiency of a predator in regulating the population dynamics of a prey. We investigated the functional response of Coccinella septempunctata L. (Coleoptera: Coccinellidae) to varying densities of Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae). The results revealed that the linear coefficient, P₁ in the reduced logistic model was found significantly negative for the 4^th instar larvae and adult male and female of C. septempunctata (?0.002, ?0.004 and???0.002, respectively) indicating a type II functional response. The parameter estimates of adult male, female and 4^thinstar larvae of C. septempunctata calculated through Holling's disc model revealed that the highest attack rate (a) (1.047?±?0.014), shortest handling time (T_h) (0.0984?±?0.024?h) and largest maximum capture rate (T/T_h) (243.902) was exhibited by female. Parameter estimates calculated through Rogers’s equation also showed the same sequence where maximum attack rate (a) of 0.00256?±?0.0003 was exhibited by female followed by 4^th instar larvae (0.00251?±?0.0005). The shortest handling time (T_h) (0.210?±?0.003?h) and highest maximum capture rate (T/T_h) (114.17) was also exhibited by female. Comparison of functional response curves of adult male, female and 4^th instar larvae revealed that maximum consumption of prey at all the densities offered was shown by female followed by 4^thinstar larvae. The study manifested that C. septempunctata could be an efficient biocontrol agent of pea aphid, A. pisum.     

Repolarization Parameters Are Associated With Mortality In Chagas Disease Patients In The United States

Objective

The goal of this study was to examine the association between ECG repolarization parameters and mortality in Chagas disease (CD) patients living in the United States.

Methods

CD patients with cardiomyopathy (CM) and bundle branch block (BBB) or BBB alone were compared to age- and sex-matched controls. QT interval, QT dispersion (QTd), T wave peak to T wave end duration (Tp-Te) and T wave peak to T wave end dispersion ((Tp-Te)d) were measured. Presence of fractionated QRS (fQRS) was also assessed. The main outcome measure was the association between ECG parameters and mortality or need for cardiac transplant.

Results

A total of 18 CM and 13 BBB CD patients were studied with 97% originating from Mexico or Central America. QTd (60.0±15.0 ms vs 43.5±9.8 ms, P=0.0002), Tp-Te (102.6±29.3 ms vs 77.1±11.0 ms, P=0.0002) and (Tp-Te)d (39.5±9.4 ms vs 22.7±7.6 ms, P<0.0001) were prolonged in CD CM patients compared to CM controls. Chagas CM patients had more fQRS then controls (84.2±0.10% vs 33.3±0.11%, p=0.0005). QTd (59.9±15.0 ms vs 29.5±6.9 ms, P=0.0001) and (Tp-Te)d (40.0±15.9 ms vs 18.5±5.4 ms, p<0.0001) were longer in the CD BBB group compared to BBB controls. Univariate analysis showed QTd (56.9±15.0 ms vs 46.5±17.3 ms, p=0.0412) and (Tp-Te)d (36.8±13.5 ms vs 28.5±13.3 ms, p=0.0395) were associated with death and/or need for cardiac transplant.

Conclusion

Our results indicate that P-max and PD are useful electrocardiographic markers for identifying the β-TM-high-risk patients for AF onset, even when the cardiac function is conserved.     

DTI定量参数对脑胶质瘤的诊断价值及其与血管内皮生长因子、细胞核增殖相关抗原的关系

目的:探讨扩散张量成像(DTI)定量参数对脑胶质瘤的诊断价值及其与血管内皮生长因子(VEGF)、细胞核增殖相关抗原(Ki-67)的关系。方法:选取2014年6月到2017年6月期间在我院接受治疗的90例脑胶质瘤患者,根据病理分级的不同分为中低级别组(n=46)和高级别组(n=44),比较两组患者表观扩散系数(ADC)值、各向异性分数(FA)值、相对表观扩散系数(rADC)值、相对各向异性分数(rFA)值、VEGF和Ki-67的阳性率,分析ADC值、FA值、rADC值、rFA值与VEGF、Ki-67表达的相关性。结果:高级别组的ADC值、FA值、rADC值和rFA值低于中低级别组(P0.05)。高级别组病理组织中VEGF、Ki-67的阳性表达率高于中低级别组(P0.05)。经Spearman相关分析显示,ADC值、FA值、rADC值和rFA值与VEGF、Ki-67的表达水平均呈负相关(P0.05)。结论:DTI定量参数与脑胶质瘤病理分级和VEGF、Ki-67的表达水平密切相关。     

螺旋对称病毒衣壳参数的研究

本文从数学角度分析和研究了螺旋对称病毒衣壳参数、整理出衣壳参数２０多个,对每一个参数的概念、含义等给予了明确的认定。提示了参数间的关系,推导出了一些计算参数值的公式。