LH responses to single doses of exogenous GnRH in the Cape mole rat (Georychus capensis): the pituitary potential for opportunistic breeding

The Cape mole rat Georychus capensis is a solitary mole rat that inhabits the winter rainfall region of the Western Cape Province of South Africa. Circulating basal concentrations of luteinizing hormone (LH) were found to be significantly higher in the breeding season in both sexes. During both the breeding and non-breeding season, administration of exogenous gonadotropin-releasing hormone (GnRH) increased circulatory LH levels. The magnitude of the LH response to an overdose of exogenous GnRH both in and out of the breeding season in males and females was not significantly different. Typically, seasonally breeding species exhibit a down-regulation of the pituitary and reproductive functions out of the breeding season. It appears that there is no down-regulation of GnRH receptors at the level of the pituitary out of the breeding season, because the pituitary responds to an exogenous GnRH challenge equally both in and out of the breeding period. The Cape mole rat exhibits the potential for opportunistic breeding out of the breeding period, provided that environmental factors are favourable. This finding questions whether this mole rat is actually a seasonal breeder or whether reproduction is hindered by the ecological constraint of the lack of opportunities to burrow and find mates at certain times of the year.     

An Investigation of Structural Stability and Internal Rotation in 3-Cyclopropenecarboxaldehyde and 3-Cyclopropenecarboxylic Acid Fluoride by ab initio Calculations

The structural stability and internal rotation in 3-cyclopropenecarboxaldehyde and 3-cyclo-propenecarboxylic acid fluoride were investigated by ab initio calculations with a 6-31G* atomic basis in the latter and a 6-311G* atomic basis set in the former case. For the sake of comparison also results obtained with a 3-21G basis are given in the paper. As expected, it turned out that this basis set is not large enough for three-membered rings. The calculations were carried out both at the Restricted Hartree-Fock (HF) and the second order Moller-Plesset (MP2) levels. The trans-form is predicted to be the lower energy conformer for both molecules. However, in case of the fluoride the two conformers have nearly the same energy. Full optimization was performed at the transition states and the asymmetric potential function for the CXO internal rotations was predicted for both molecules.     

Determination of lormetazepam and its main metabolite in serum using micellar electrokinetic capillary chromatography with direct injection and ultraviolet absorbance detection

The use of micellar electrokinetic chromatography for the determination of lormetazepam and its metabolite, lorazepam, in serum samples at a concentration range of therapeutic interest was investigated. The separation was carried out at 30 degrees C and 25 kV, using a 15 mM borate-phosphate buffer (pH 8) with 30 mM sodium dodecyl sulfate as the separation electrolyte and 15% methanol as organic modifier. The analyses were carried out in 20 min under these conditions. Detection limits of 0.5 mg l(-1) were achieved for both benzodiazepines in serum. This method was employed for the quantitative resolution of both drugs (at different concentration ratios) in serum with very good recoveries.     

Modeling and simulation of competition between two microorganisms for a single inhibitory substrate in a biofilm reactor

A simple biofilm model was developed to simulate the competition between two microorganisms for a common inhibitory substrate. The following assumptions were made for the simulations: (1) the biofilm has a uniform thickness and is composed of 5 segments, (2) growth of two microorganisms A and B which utilize the common substrate is expressed by the Haldane kinetics with a spatial limitation term and is independent of the other microorganism in the biofilm reactor, and (3) diffusion of the substrate, movement of the microorganisms, and continuous loss of the biomass by shearing are expressed by Fick's Law-type equations. The qualitative behavior of the biofilm reactor is characterized by five regions, I-V, depending on the operation conditions, the substrate concentration in feed, and the dilution rate. In region I, both microorganisms are washed out of the biofilm reactor. In region II, microorganism B is washed out, and in region III, microorganism A is washed out of the biofilm. In region IV, both microorganisms coexist with one another. In region V, both microorganisms coexist with a sustained oscillatory behavior. Convergence to regions I-V depends on the initial conditions. In regions II-V, washout of either or both microorganisms is also observed with initial conditions too far away.     

Phylogenetic conservatism and trait correlates of spring phenological responses to climate change in northeast China

Climate change has resulted in major changes in plant phenology across the globe that includes leaf‐out date and flowering time. The ability of species to respond to climate change, in part, depends on their response to climate as a phenological cue in general. Species that are not phenologically responsive may suffer in the face of continued climate change. Comparative studies of phenology have found phylogeny to be a reliable predictor of mean leaf‐out date and flowering time at both the local and global scales. This is less true for flowering time response (i.e., the correlation between phenological timing and climate factors), while no study to date has explored whether the response of leaf‐out date to climate factors exhibits phylogenetic signal. We used a 52‐year observational phenological dataset for 52 woody species from the Forest Botanical Garden of Heilongjiang Province, China, to test phylogenetic signal in leaf‐out date and flowering time, as well as, the response of these two phenological traits to both temperature and winter precipitation. Leaf‐out date and flowering time were significantly responsive to temperature for most species, advancing, on average, 3.11 and 2.87 day/°C, respectively. Both leaf‐out and flowering, and their responses to temperature exhibited significant phylogenetic signals. The response of leaf‐out date to precipitation exhibited no phylogenetic signal, while flowering time response to precipitation did. Native species tended to have a weaker flowering response to temperature than non‐native species. Earlier leaf‐out species tended to have a greater response to winter precipitation. This study is the first to assess phylogenetic signal of leaf‐out response to climate change, which suggests, that climate change has the potential to shape the plant communities, not only through flowering sensitivity, but also through leaf‐out sensitivity.     

Metabolite profiling: from diagnostics to systems biology

The concept of metabolite profiling has been around for several decades, but only recent technical innovations have allowed metabolite profiling to be carried out on a large scale - with respect to both the number of metabolites measured and the number of experiments carried out. As a result, the power of metabolite profiling as a technology platform for diagnostics, and the research areas of gene-function analysis and systems biology, is now beginning to be fully realized.     

Evaluation of a patient-specific cost function to predict the influence of foot path on the knee adduction torque during gait

A large external knee adduction torque during gait has been correlated with the progression of knee osteoarthritis (OA). Though foot path changes (e.g. toeing out) can reduce the adduction torque, no method currently exists to predict whether an optimal foot path exists for a specific patient. This study evaluates a patient-specific optimization cost function to predict how foot path changes influence both adduction torque peaks. Video motion and ground reaction data were collected from a patient with knee OA performing normal, toe out, and wide stance gait. Joint and inertial parameters in a dynamic, 27 degree-of-freedom, full-body gait model were calibrated to the patient's normal gait data. The model was then used in gait optimizations that predicted how the patient's adduction torque peaks would change due to changes in foot path. The cost function tracked the patient's normal gait data using weight factors calibrated to toe out gait and tested using wide stance gait. For both gait motions, the same cost function weights predicted the change in both adduction torque peaks to within 7% error. With further development, this approach may eventually permit the design of patient-specific rehabilitation procedures such as an optimal foot path for patients with knee OA.     

Chromosome and cytome analysis of the somatic cells of nuclear-chemical production workers with incorporated 239Pu

The analysis of plutonium production factors has been carried out by using two methodical approaches: assessment of chromosomal aberrations level in routine and G-banded metaphases and molecular-cytogenetic investigation of aneugenic/clastogenic damages in cytokinesis-block binuclear lymphocytes by FISH with centromere specific DNA probes. The obtaining data point out for the first time about both aneugenic and clastogenic influences of incorporated 239Pu with activity range from 0.37 to 6.95 kBq. Correlation analysis of chromosome aberrations with cytome abnormalities allowed finding significant connection between number parameters of metaphase and interphase approaches. The results of this study support the suggestion that aberrant chromosomes are involved preferable in aneugenic events. The FISH technique in binucleated cytokinesis-blocked lymphocytes allows extending of detecting spectrum of chromosome damages and glance of aneugenic mechanisms. Correlations between metaphase and interphase-FISH results point out a high sensitivity of FISH cytome assay, which could be used as an independent test for detection both clastogenic and aneugenic environment influences.     

Determination of aluminum by neutron activation analysis in human lung tissue and in chemicals for dialysis of uremic patients

Aluminum (Al) determination in human lung tissue, in chemicals for dialysis fluids, and in commercially available dialysis solutions is carried out using both Instrumental and Radiochemical Neutron Activation Analysis (INAA and RNAA). For some matrices, pre-and post-irradiation Al separations are tested. Chelex 100 resin and HDEHP, this latter adsorbed both on teflon and polyurethane foam, are employed for the pre-irradiation Al separations. The postirradiation procedures are performed using roughly the same schemes; the conventional Al precipitation as hydroxide is also carried out. Al values found in lungs of workers exposed to Al containing dust appear to be much higher than those found for unexposed people. Chemicals analyzed seem pure enough to give suitable dialysis solutions; for commercially available dialysis fluids, a 10-fold reduction of Al content should be convenient.     

Activity of the climbing fiber innervating various Purkinje cells

Low-amplitude potentials (10-130 microV) related to the action of a distant branch of the climbing fiber, which elicits complex spikes of the reference Purkinje cell were revealed by means of potential averaging synchronously with complex spikes of Purkinje cells in 10 out of 255 paired records of cerebellar Purkinje cells activity and extracellular field potentials at interelectrode distances of 200-1500 microns. These potential waves had a stable form in independent sets of data. In 3 out of 10 cases, the low-amplitude potentials included a slow (about 100 ms in duration) component. In one case, both test and reference electrodes recorded both simple and complex spikes of different Purkinje cells so that complex spikes of both cells were practically synchronous (conditional probability of complex spikes p = 0.97, onset time difference 0.54 ms). Thus for the first time in cerebellar physiology both simple and complex spikes activity of two Purkinje cells controlled by the same climbing fiber was recorded.     

Conformational study of angiotensin II

Conformational free energy calculations using an empirical potential ECEPP/3 (Empirical Conformational Energy Program for Peptides, Version 3) were carried out on angiotensin II (AII) of sequence Asp-Arg-Val-Tyr-Ile-His-Pro-Phe to find the stable conformations of the free state in the unhydrated and the hydrated states. A conformational analysis of the unhydrated state was carried out using the buildup procedure. The free energy calculation using the hydration shell model was also carried out to obtain the stable conformation of the hydrated state. The calculated stable conformations of AII in both states have a partially right-handed α-helical structure stabilized by short- and medium-range interactions. The similarity between the lowest free energy conformations of the unhydrated and hydrated states suggests that the hydration might not be important to stabilize the overall conformation of AII in a free state. The absence of any intramolecular interaction of the Tyr side chain suggests the possible interaction of this residue with the receptor. In this study, we found that the low free energy conformations contain both the parallel-plate and the perpendicular-plate geometries of the His and Phe rings, suggesting the coexistence of both conformations. © 1996 John Wiley & Sons, Inc.     

A Taxonomy of Business Process Modeling and Information Systems Modeling Techniques

Modeling always has been at the core of both organizational design and information systems (IS) development. Models enable decision makers to filter out the irrelevant complexities of the real world, so that efforts can be directed toward the most important parts of the system under study. However, both business analysts and IS professionals may find it difficult to navigate through a maze of theoretical paradigms, methodological approaches, and representational formalisms that have been proposed for both business process modeling (BPM) and information systems modeling (ISM). This paper sets out to put an order to this chaos by proposing an evaluation framework and a novel taxonomy of BPM and ISM techniques. These findings, coupled with a detailed review of BPM and ISM techniques, can assist decision makers in comparatively evaluating and selecting suitable modeling techniques, depending on the characteristics and requirements of individual projects.     

用于胚胎干细胞分离培养的滋养层细胞株的建立

具有发育全能性的胚干细胞在分离培养时必须依赖滋养层细胞~［１］,本研究旨在建议一个可供使用的滋养层细胞株。将小鼠胎仔去头、内脏、四肢后用胰酶消化,用作成纤维细胞的初代培养,２～３６后继代培养,并开始进行选择和株化,获得的继代培养的成纤维细胞可用于制备胚干细胞培养所需滋养层,亦可冷冻保存备用。本实验所建立的小鼠成纤维细胞系,已成功地用于胚干细胞的分离培养,证明可作为分离培养胚干细胞时所需的滋养层细胞来源。     

四川平武白马藏族外眼形态学特征

本文对四川省平武县白马藏族212人和绵阳地区汉族251人进行了外眼共九个项目形态学调查。对各项分别进行了生长发育趋势的探讨及性别间、族别间的差异显著性检验。     

Eco(nomics/logy)

This note discusses the analytic tools available for studying the interrelations between the economy and the ecological system. It points out the importance of the concept of cooperative games as an addition to the emphasis on non-cooperative games in both economics and ecology. The relation between both concepts of the games and the market system is discussed.     

两种群相互竞争的SIRS传染病模型的稳定性

研究了一类两种群相互竞争的SIRS传染病模型,得到了一些平衡点稳定与否的阈值条件。揭示了两种群共存时,交叉传染对疾病传播的本质影响,即在无交叉传染疾病绝灭的情况下（一定条件时）,若引入交叉传染,在相同的条件下,疾病就可能流行起来。     

Polymorphism of microsatellite DNA and study of maize genetic resources

Microsatellite loci PCR-analysis of 80 maize lines and hybrids from two regions of Ukraine has been carried out. Allelic sets individual for each maize genotype have been revealed and discrimination potential of applied marker system has been determined. Comparative analysis of frequencies of alleles and genotypes occurrence in both samples has been carried out and possible participation of the investigated SSR-loci in formation of maize adaptability system has been shown.     

Evaluation of an indirect fluorescent antibody test (IFAT) for demonstration of antibodies to Toxoplasma gondii in the sea otter (Enhydra lutris)

An indirect fluorescent antibody test (IFAT) for detection of Toxoplasma gondii infection was validated using serum from 77 necropsied southern sea otters (Enhydra lutris nereis) whose T. gondii infection status was determined through immunohistochemistry and parasite isolation in cell culture. Twenty-eight otters (36%) were positive for T. gondii by immunohistochemistry or parasite isolation or both, whereas 49 (64%) were negative by both tests. At a cutoff of 1:320, combined values for IFAT sensitivity and specificity were maximized at 96.4 and 67.3%, respectively. The area under the receiver-operating characteristic curve for the IFAT was 0.84. A titer of 1:320 was used as cutoff when screening serum collected from live-sampled sea otters from California (n = 80), Washington (n = 21), and Alaska (n = 65) for T. gondii infection. Thirty-six percent (29 out of 80) of California sea otters (E. lutris nereis) and 38% (8 out of 21) of Washington sea otters (E. lutris kenyoni) were seropositive for T. gondii, compared with 0% (0 out of 65) of Alaskan sea otters (E. lutris kenyoni).