The influence of competitor density on space use in juvenile striped plateau lizards (Sceloporus virgatus)

To investigate the role of competitor density in influencing space use patterns of juvenile striped plateau lizards (Sceloporus virgatus), a density manipulation experiment was conducted within large (800 m²) field enclosures treated with low (20) and high (60) densities of hatchlings. Enclosures were monitored for 10 months, after which the experiment was replicated. Home range and core area sizes after release of lizards and initial establishment in the fall were significantly reduced in the high-density treatments; fall home range shape, measured as the perimeter-to-area ratio, was significantly reduced in low-density treatments; no significant differences were detected between treatments in core area shape or overlap. During the spring/early summer activity season after the lizard's first winter, no significant differences between density treatments were detected for any of these variables, as enclosure densities had converged between treatments. Individuals in high-density enclosures had increased their space use as competitor density had declined. These results illustrate that competitor density has significant influence on space use by juvenile lizards.     

Suppression of antigen-specific lymphocyte activation in modeled microgravity

Various parameters of immune suppression are observed in lymphocytes from astronauts during and after a space flight. It is difficult to ascribe this suppression to microgravity effects on immune cells in crew specimens, due to the complex physiological response to space flight and the resultant effect on in vitro immune performance. Use of isolated immune cells in true and modeled microgravity in immune performance tests, suggests a direct effect of microgravity on in vitro cellular function. Specifically, polyclonal activation of T-cells is severely suppressed in true and modeled microgravity. These recent findings suggest a potential suppression of oligoclonal antigen-specific lymphocyte activation in microgravity. We utilized rotating wall vessel (RWV) bioreactors as an analog of microgravity for cell cultures to analyze three models of antigen-specific activation. A mixed-lymphocyte reaction, as a model for a primary immune response, a tetanus toxoid response and a Borrelia burgdorferi response, as models of a secondary immune response, were all suppressed in the RWV bioreactor. Our findings confirm that the suppression of activation observed with polyclonal models also encompasses oligoclonal antigen-specific activation.     

Study on genotoxic effects of the space environment: a comparison between experienced cosmonauts and unexposed Russian twins

The molecular analysis of T-lymphocytes from experienced cosmonauts and seven pairs of unexposed twins was performed [M. Khaidakov, D. Young, H. Erfle, A. Mortimer, Y. Voronkov, B.W. Glickman, Molecular analysis of mutations in T-lymphocytes from experienced soviet cosmonauts, Environ. Mol. Mutagen, 30 (1997) 21–30; J. Curry, G. Bebb, J. Moffat, D. Young, M. Khaidakov, A. Mortimer, B.W. Glickman, Similar mutant frequencies observed between monozygotic twins, Human Mutation, 9 (1997) 445–451]. Hprt mutant frequencies (MF) in both datasets were considerably higher (38.0±14.6×10⁻⁶ in cosmonauts, and 18.5±8.9×10⁻⁶ in twins) than in the background Western control (8–12×10⁻⁶), [A.D. Tates, F.J. van Dam, H. van Mossel, H. Shoemaker, J.C.P. Thijssen, V.M. Woldring, A.H. Zwinderman, A.T. Natarajan, Use of the clonal assay for the measurement of frequencies of HPRT mutants in T-lymphocytes from five control populations, Mutation Res., 253 (1991) 199–213; R.F. Branda, L.M. Sullivan, J.P. O'Neill, M.T. Falta, J.A. Nicklas, B. Hirsch, P.M. Vacek, R.J. Albertini, Measurement of HPRT mutant frequencies in T-lymphocytes from healthy human populations, Mutation Res., 285 (1993) 267–279]. The distribution of mutations by class in the twin dataset was essentially similar to the background Western control, whereas cosmonaut samples demonstrated a significant excess of splice errors and complex mutations. The distribution of base substitutions showed similar trends in both the cosmonaut and twin samples, which are quite distinct compared to those seen in the Western control. The differences observed between cosmonaut and twin samples (a 2-fold higher MF and an excess of complex mutations in cosmonaut mutational spectra) could be an indication of possible effects of the space environment. However, these changes could also be age-related because the twin group was, on average, 17 years younger. Moreover, very similar patterns of base substitution distribution in both datasets suggest the involvement of certain region-specific factors reflected in mutational spectra. In order to discriminate between occupation and region-specific factors contributing to mutagenesis, an additional study involving trainees and cosmonauts with recent long-term flight experience is required.     

Monte Carlo mixture model of lifetime cancer incidence risk from radiation exposure on shuttle and international space station

Estimating uncertainty in lifetime cancer risk for human exposure to space radiation is a unique challenge. Conventional risk assessment with low-linear-energy-transfer (LET)-based risk from Japanese atomic bomb survivor studies may be inappropriate for relativistic protons and nuclei in space due to track structure effects. This paper develops a Monte Carlo mixture model (MCMM) for transferring additive, National Institutes of Health multiplicative, and multiplicative excess cancer incidence risks based on Japanese atomic bomb survivor data to determine excess incidence risk for various US astronaut exposure profiles. The MCMM serves as an anchor point for future risk projection methods involving biophysical models of DNA damage from space radiation. Lifetime incidence risks of radiation-induced cancer for the MCMM based on low-LET Japanese data for nonleukemia (all cancers except leukemia) were 2.77 (90% confidence limit, 0.75-11.34) for males exposed to 1 Sv at age 45 and 2.20 (90% confidence limit, 0.59-10.12) for males exposed at age 55. For females, mixture model risks for nonleukemia exposed separately to 1 Sv at ages of 45 and 55 were 2.98 (90% confidence limit, 0.90-11.70) and 2.44 (90% confidence limit, 0.70-10.30), respectively. Risks for high-LET 200 MeV protons (LET=0.45 keV/micrometer), 1 MeV alpha-particles (LET=100 keV/micrometer), and 600 MeV iron particles (LET=180 keV/micrometer) were scored on a per particle basis by determining the particle fluence required for an average of one particle per cell nucleus of area 100 micrometer(2). Lifetime risk per proton was 2.68x10(-2)% (90% confidence limit, 0.79x10(-3)%-0. 514x10(-2)%). For alpha-particles, lifetime risk was 14.2% (90% confidence limit, 2.5%-31.2%). Conversely, lifetime risk per iron particle was 23.7% (90% confidence limit, 4.5%-53.0%). Uncertainty in the DDREF for high-LET particles may be less than that for low-LET radiation because typically there is very little dose-rate dependence. Probability density functions for high-LET radiation quality and dose-rate may be preferable to conventional risk assessment approaches. Nuclear reactions and track structure effects in tissue may not be properly estimated by existing data using in vitro models for estimating RBEs. The method used here is being extended to estimate uncertainty in spacecraft shielding effectiveness in various space radiation environments.     

Application of real-time radiation dosimetry using a new silicon LET sensor

A new type of real-time radiation monitoring device, RRMD-III, consisting of three double-sided silicon strip detectors (DSSDs), has been developed and tested on-board the Space Shuttle mission STS-84. The test succeeded in measuring the linear energy transfer (LET) distribution over the range of 0.2 keV/micrometer to 600 keV/micrometer for 178 h. The Shuttle cruised at an altitude of 300 to 400 km and an inclination angle of 51.6 degrees for 221.3 h, which is equivalent to the International Space Station orbit. The LET distribution obtained for particles was investigated by separating it into galactic cosmic ray (GCR) particles and trapped particles in the South Atlantic Anomaly (SAA) region. The result shows that the contribution in dose-equivalent due to GCR particles is almost equal to that from trapped particles. The total absorbed dose rate during the mission was 0.611 mGy/day; the effective quality factor, 1.64; and the dose equivalent rate, 0.998 mSv/day. The average absorbed dose rates are 0.158 mGy/min for GCR particles and 3.67 mGy/min for trapped particles. The effective quality factors are 2.48 for GCR particles and 1.19 for trapped particles. The absorbed doses obtained by the RRMD-III and a conventional method using TLD (Mg(2)SiO(4)), which was placed around the RRMD-III were compared. It was found that the TLDs showed a lower efficiency, just 58% of absorbed dose registered by the RRMD-III.     

Characterization of early deaths of non-Saccharomyces yeasts in mixed cultures with Saccharomyces cerevisiae

The survival of Kluyveromyces thermotolerans and Torulaspora delbrueckii in mixed cultures with Saccharomyces cerevisiae was examined at low oxygen availability in a defined grape juice medium. In these fermentations, K. thermotolerans and T. delbrueckii died off earlier than S. cerevisiae, and K. thermotolerans and T. delbrueckii exhibited parabolic death kinetics. Furthermore, the early deaths seemed to be non-apoptotic in nature. In order to understand the mechanism causing the early deaths, various single- and mixed-culture fermentations were carried out. The early deaths could not be explained by nutrient depletion or the presence of toxic compounds. Rather, they seemed to be mediated by a cell-to-cell contact mechanism at high cell densities of S. cerevisiae, and to a lesser ability of K. thermotolerans and T. delbrueckii to compete for space, as compared to S. cerevisiae. These results contribute to an increased understanding of why K. thermotolerans and T. delbrueckii die off before S. cerevisiae in wine fermentations.     

Proximate composition, fatty acids, cholesterol, minerals in frozen red porgy

The proximate composition of frozen red porgy (Pagrus pagrus) was determined. The moisture, ash, protein and total lipids (45.5+/-1.4% PL of which 90.4+/-2.0% PhL) were found to be 71.7+/-1.0%, 1.73+/-0.12%, 21.5+/-0.8% and 0.81+/-0.09% of the wet muscle tissue, respectively. 16:0 and 18:0 were the main SFA, 18:1 (omega-9 and omega-7) the main MUFA while DHA, EPA and arachidonic acid were the main polyunsaturated fatty acids (PUFA). The SFA/PUFA ratio was 1.5 and the omega-3/omega-6 ratio was 3.02. The cholesterol content was found to be 8.18+/-0.34 mg/100 g of the wet muscle tissue. Ni, Cr, Mn, Cu, Zn, Fe and Mg were determined in the muscles, skin, hepatopancreas and head of the fish. The covering percentage of the recommended daily allowance/intake (RDA/RDI) for each mineral, in the muscle tissue, has been calculated to 14.2% (males) and 7.89% (females) for Fe, 2.87% for Cu, 4.07% for Zn 0.4% for Mn, 13.9% for Ni, 20.2% for Cr and 10.4% for Mg.     

繁殖-育幼期雌性大熊猫的空间利用与活动模式特征

繁殖期间的空间利用与活动模式特征是野生动物长期适应环境的具体表现,研究野生动物繁殖期间行为特征与策略是动物生态学研究中最重要的基础问题之一。2010年3月至2012年3月,我们利用内置记录活动水平传感器的GPS项圈记录了1只受孕、产仔并育幼的野生大熊猫（Ailuropoda melanoleuca）的活动位点和活动水平。研究了该大熊猫各繁殖阶段（交配后期、产仔期和育幼期）的空间利用与活动模式特征。结果表明：在交配后期（2010年春季,即4-6月）,雌性大熊猫活动空间范围较大为3.49 km²,其日平均活动距离较大,活动水平也相对较强;在产仔期前后（2010年夏秋季,即7-10月）,雌性大熊猫的活动范围明显缩小为0.42 km²,日平均活动距离和活动水平都明显减低;自2010年冬季（2010年11月至2011年3月）开始雌性大熊猫带仔生活,其家域面积逐渐增大,且趋向稳定 （0.84~1.19 km²）,日平均活动距离和活动水平都开始逐渐增大。雌性大熊猫在求偶交配、受孕、产仔和育幼过程中的空间利用与活动模式特征反映了大熊猫在繁殖期间的行为策略。本研究结果可为繁殖期间大熊猫及栖息地的保护管理政策制定提供科学依据。     

463例口腔颌面部间隙感染临床病例的回顾性研究

目的:分析口腔颌面部间隙感染的临床特点、诊治要点、病原菌的分布情况以及抗生素使用时长的影响因素。方法:回顾性研究四川大学华西口腔医院2009年至2013年收治的463例颌面部间隙感染患者的临床资料,对性别、入院年龄、体温、入院白细胞数、感染来源、是否进行细菌培养、住院时长等数据进行统计学分析。结果:463例患者的年龄为1~82岁,平均年龄47岁;男性265人(57.24%),女性198人(42.76%);大多数患者平均入院体温、入院时白细胞数、入院中性粒细胞百分数均高于正常值。进行分泌物细菌学培养的患者206人(44.49%),在送检的206份标本中,细菌培养结果阳性的有127例,阴性的79例,感染细菌大部分为链球菌属。抗生素使用时长与患者的年龄、抗生素使用种类、细菌培养结果、是否伴有基础疾病等因素均有显著相关性(P0.05)。结论:患者入院体温、白细胞数、中性粒细胞百分比仍为临床诊治感染的重要指征。及时行脓肿切开引流对控制间隙感染有重要意义;积极进行分泌物细菌培养,对选择正确的抗生素及减少抗生素的使用时长具有指导价值。     

A Simple Method for Searching Intracellular Space Structures in Plant Tissues

After being fixed, plant leaves were embedded in polyethylene glycol (PEG, molecular weight 4000) and sectioned 5–10μm in thickness. PEG in the slices was dissolved during the routine process and the slices were observed under Hitachi S-450 scanning electron microscope By using this method, it is easy to study the space structures of organelles such as chloroplasts, mitochondria, nucleus, nucleolus, etc. as well as their space inter relations.