转小鼠金属硫蛋白(MT)基因烟草不同器官中金属离子铅和锌的分布

转金属硫蛋白(MT)基因植物具有清除重金属污染的能力,但是金属离子在植物体内的分布研究较少。文章以多代培育纯合的转MT烟草为材料,研究了转MT基因烟草积累铅和锌以及铅和锌在不同器官的分布情况。结果表明转基因植株的老叶、茎部和根部铅和锌积累量显著高于普通烟草植株,整株的铅和锌含量分别提高了21.8%和27.2%。铅和锌在植物体内的分布也发生了变化,转基因植株老叶和根中的铅含量分别高出普通烟草同位置的30.2%和47.8%,锌在转基因植株老叶、茎和根中的含量分别高出普通烟草同位置的44.7%,29.2%和21.6%,说明铅更容易在转基因植株老叶和根中积累,而锌更容易在转基因植株的老叶和茎中积累。     

‘Phase transitions’ in bacteria – From structural transitions in free living bacteria to phenotypic transitions in bacteria within biofilms

Phase transitions are common in inanimate systems and have been studied extensively in natural sciences. Less explored are the rich transitions that take place at the micro- and nano-scales in biological systems. In conventional phase transitions, large-scale properties of the media change discontinuously in response to continuous changes in external conditions. Such changes play a significant role in the dynamic behaviours of organisms. In this review, we focus on some transitions in both free-living and biofilms of bacteria. Particular attention is paid to the transitions in the flagellar motors and filaments of free-living bacteria, in cellular gene expression during the biofilm growth, in the biofilm morphology transitions during biofilm expansion, and in the cell motion pattern transitions during the biofilm formation. We analyse the dynamic characteristics and biophysical mechanisms of these phase transition phenomena and point out the parallels between these transitions and conventional phase transitions. We also discuss the applications of some theoretical and numerical methods, established for conventional phase transitions in inanimate systems, in bacterial biofilms.     

ICP-AES测定云南楚雄糖尿病患者发样微量元素的研究

探讨微量元素与糖尿病间的关联性及临床意义。采用ICP-AES等离子体发射光谱仪测定了楚雄地区糖尿病患者人发中11种元素,采用2,3-二氨基萘荧光法测定发样中的硒元素。选取糖尿病患者120例,对照组35例。糖尿病组发样中常量元素Ca、Mg低于对照组,P高于对照组;除Cd、Cr、Fe外,微量元素Zn、Se、Ni、Mn、Cu等5种元素低于对照组,并有显著差异(P0.01)。糖尿病组间性别比较数据显示男性除发Ni、Mn、P外,其余元素含量均低于女性,其中发锌远低于女性。3个不同年龄段糖尿病人群的微量元素含量变化显示Fe、P2种元素随年龄增加含量增高;Mg、Cd2种元素随年龄增加含量减少;其余各元素变化情况为Fe、P元素在老年组中较高,Cu、Cd、Mg较低;Mn、Cr、Cu元素含量在中年组中较高,而Zn、Se略低;Zn、Se在青年组较高,而Mn、Cr低。城市人群发中Zn、Cd、Cu、Mg、Ca含量比农村人群高;Se元素含量二者间差别也不大,其余元素含量均低于农村人群。楚雄地区糖尿病患者发中Zn、Se、Mg、Mn4种元素水平低,楚雄地区糖尿病患者致病原因可能与地区属低Se水平和患者体内硒水平低有关。     

Sex differences in human cardiovascular responses to external excitation

Summary The purpose of this study was to investigate the sex particularities in human cardiovascular responses to different external influences using the traditional physiological approach and non-traditional methods of dynamical systems theory. Measurements were taken in 21 healthy women and 15 men exposed to noise stress, passive coping, and in 35 women and 25 men exposed to double mental arithmetic stress, active coping. Results showed that, firstly, cardiovascular reactivity in men and women was determined by the type of stress. Thus, in a majority of humans heart rate did not change during noise but increased during mental stress, blood pressure decreased during noise but increased during mental stress. Secondly, results demonstrated the significant sex differences in the basal and stress cardiovascular activity. So, the women showing the greater basal and stress heart rate displayed the hypotensive responses to passive coping more often and the hypertensive responses to active coping less often than men. Thirdly, the changes in normalized entropy of the electrocardiogram signal, reflecting the changes in heart physiological variability, also depended on the sex of subjects and the nature of stress. During noise normalized entropy increased in a majority of women but decreased in a majority of men. Mental stress caused both decreases and increases in normalized entropy in men and women. But the increases in normalized entropy during stress and especially during recovery were greater in women than in men. Normalized entropy was demonstrated to be a more sensitive marker of sex and individual differences in cardiovascular responses to stress than heart rate and blood pressure. Results suggest that the lower blood pressure reactions and the greater increases in normalized entropy,i.e. in physiological heart variability, may partly result in higher cardiovascular stress resistance in women relative to men. Paper presented at the International Workshop ?Fluctuations in Physics and Biology: Stochastic Resonance, Signal Processing and Related Phenomena?, Elba, 5–10 June 1994.     

降雨对无线激光通信的影响

通过激光信号在雨介质中传输的实验发现,在大雨环境下,激光信号透射率要比在小雨或微雨的情况下大。这说明光信号在小雨时衰减较大,在大雨时衰减较小。这一现象与人们通常所认为的有所不同。针对降雨对激光信号的影响,根据Mie散射理论和Weibull雨滴尺寸分布模型,分析了不同尺寸的粒子对光的散射作用以及对衰减效率因子的影响,推导出单球粒子对光波的衰减公式,得到了衰减与降雨率的确定关系。通过数值计算发现,与小粒子相比大粒子的前向散射光强更大且更加集中;激光信号在雨介质中传输时,衰减系数在小雨时较大,中雨、大雨时较小,暴雨时不断增大。这一结果与实际情况较吻合,为激光在通信系统中的应用提供了一定的理论依据。     

Spatial unmasking of nearby pure-tone targets in a simulated anechoic environment

Detection thresholds were measured for different spatial configurations of 500- and 1000-Hz pure-tone targets and broadband maskers. Sources were simulated using individually measured head-related transfer functions (HRTFs) for source positions varying in both azimuth and distance. For the spatial configurations tested, thresholds ranged over 50 dB, primarily as a result of large changes in the target-to-masker ratio (TMR) with changes in target and masker locations. Intersubject differences in both HRTFs and in binaural sensitivity were large; however, the overall pattern of results was similar across subjects. As expected, detection thresholds were generally smaller when the target and masker were separated in azimuth than when they were at the same location. However, in some cases, azimuthal separation of target and masker yielded little change or even a small increase in detection threshold. Significant intersubject differences occurred as a result both of differences in monaural and binaural acoustic cues in the individualized HRTFs and of different binaural contributions to performance. Model predictions captured general trends in the pattern of spatial unmasking. However, subject-specific model predictions did not account for the observed individual differences in performance, even after taking into account individual differences in HRTF measurements and overall binaural sensitivity. These results suggest that individuals differ not only in their overall sensitivity to binaural cues, but also in how their binaural sensitivity varies with the spatial position of (and interaural differences in) the masker.     

绿豆酶解过程中Se的形态分布分析

采用AFS-230E 型原子荧光光度计对绿豆中Se的含量及绿豆分步酶解过程中Se的形态分布进行了分析。结果表明：（1）绿豆中Se含量为54.79 μg·g-1（干重） ;（2）通过酶解,绿豆中90%以上的Se被提取出来,而水煮对Se的提取率只有19.26%,其中淀粉酶、蛋白酶和纤维素酶酶解过程对Se的提取率分别是36.64%,55.96%和5.189%,可推断,绿豆中大部分Se被蛋白结合或络合;（3）总酶解产物中Se的有机态分布系数为59.87%,远大于绿豆汤中Se的有机态分布系数（3.64%）,其中淀粉酶解产物和蛋白酶解产物中Se的有机态分布系数分别为15.51%和44.36%,纤维素酶解产物中未检测到有机态Se,可见,Se在绿豆纤维素中主要以络合形式存在。回收实验表明,方法回收率为97.8%,RSD为1.1%（n=11 ）。     

Physics in Helsinki

I trace the origins of teaching and research in physics and astronomy during the 17th and 18th centuries at the Academy of Turku (Åbo), which was relocated to Helsinki in 1827 and renamed as the Imperial Alexander University of Finland, and which in turn in 1917 became the University of Helsinki. I discuss the growth of physics in Helsinki during the 19th century, which culminated in the opening of a large new Physical Institute in 1911, pointing out the individuals responsible for these developments and the sites associated with them. I also discuss related events, such as the founding of a new astronomical observatory and a new magnetic observatory and the development of technical education in Helsinki. I conclude by discussing the construction of an accelerator laboratory and other important developments in physics in Helsinki after 1945.     

夏秋两季洱海、太湖表层混合层的深度变化特征及其机理分析

湖泊表层混合层深度的变化不仅影响湖泊水生生态系统的演变, 而且影响流域的局地气候、降水量的时空格局等. 基于2008年夏秋两季洱海(高原湖泊)和太湖(平原湖泊)的气象与水温廓线观测资料, 分析探讨了两湖表层混合层深度的变化特征及其机制. 结果表明: 夏季洱海能维持持续的分层现象, 秋季有明显的日分层现象, 而在相应的两季中, 太湖仅可能存在日分层现象; 洱海表层混合层深度较同期太湖更浅; 太湖两季的表层混合层深度变化较洱海频繁, 即太湖水体混合与分层的交替过程对气象条件的响应较洱海更为迅速. 太湖这类浅水湖泊, 水深是抑制其存在稳定、持续分层的关键因素, 在合适的辐射条件下, 可形成日分层现象; 而洱海这类深度的湖泊, 净热量通量是影响其是否存在持续、稳定分层的主要因子. 该研究为进一步探讨湖泊与大气两种湍流运动的耦合机制及水生生态环境演替规律等提供了有力的参考.     

Seasonal variations of cytosolic antioxidant enzyme activities in the liver and white muscle of thinlip gray mullet (Liza ramada Risso) from the Adriatic Sea

The activity of cytosolic antioxidative defence enzymes in the liver and white muscle of thinlip gray mullet (Liza ramada Risso) were compared in winter and spring in the Adriatic Sea. Activity of antioxidative enzymes is functionally organized due to metabolic demands: analyses of variance and correlation analysis revealed tissue- and seasonal- specific organization of antioxidative enzymes. In winter GST activity increased in both tissues compared with spring. At the same time decreased GSH-Px and GR activities were observed and this effect was more pronounced in liver then in white muscle. From correlation analyses it is concluded that the antioxidative components correlate, but the composition of the antioxidative defence system is different in respect to season and tissue. This means that the antioxidative defence system reorganizes its structure due to oxidative demands and to protect the tissues against reactive oxygen species and to establish homeostasis. Discriminant analyses separated groups according to the complete organization of individual components of the system very well and identified individual components (CAT, GST and GR) which contribute most to the differences. Statistical differences were observed between enzyme activities in tissues (liver and muscle) in both winter and spring, and between seasons (winter and spring) for liver tissue only. Since environmental parameters, such as temperature and oxygen concentration in the sea differ with season, we conclude that in this species the tissues examined expressed their antioxidative defence systems in different ways in respect of external/environmental conditions. We propose that tissue- and seasonal- specific levels of antioxidant enzyme activities should be considered in the interpretation of data from future biomonitoring field studies, especially in relation to low temperature.     

利用原子吸收光谱法分析盐胁迫对野生披碱草矿质元素吸收和积累的影响

应用原子吸收光谱法测定了两份耐盐性不同的野生披碱草种质材料在不同盐浓度胁迫条件下根组织和叶组织中的大量元素(Na,K,Ca,Mg)和微量元素(Cu,Fe,Mn,Zn)含量,并对野生披碱草种质材料矿质元素吸收和积累的选择性与耐盐性的关系进行了分析,结果表明：随着盐胁迫浓度的升高,野生披碱草种质材料叶和根组织中Na含量不断增加,耐盐材料HS叶组织中的Na含量显著低于敏盐材料LS(P<0.05);而K和Ca含量呈下降的趋势,在高浓度盐胁迫下,耐盐材料HS中两种元素的含量显著高于敏盐材料LS(P<0.05);微量元素Fe和Zn在野生披碱草材料根、叶组织中的含量升高,Cu在根组织中的含量没有变化,但是在叶组织中升高,而Mn在根、叶组织中的含量都呈下降的趋势,耐盐材料HS叶组织和根组织中Zn和Fe含量低于敏盐材料LS,Mn含量显著高于敏盐材料LS(P<0.05)。     

火焰原子吸收光谱法测定鸭粪中铜和锌的含量

采用火焰原子吸收光谱法测定白洋淀生态养鸭场中饲料及鸭粪中的铜和锌含量,测定结果为饲料中的铜含量范围在9.7-61.55mg/kg,锌含量范围在63.14-149.07mg/kg,在禽类饲料中铜、锌含量属于较低的类型;鸭粪中铜含量范围在13.71-94.74mg/kg,锌含量范围在156.98-346.31mg/kg,参...     

普通高等学校医药类专业物理理论课教学现状调查

采用问卷调查的方式,调查了全国28省(市)69所普通高等学校医药专业(本科)物理理论课的教学情况．结果表明：经过多年的努力。医药院校的物理理论课教学取得了显著的成果;但由于学时数的削减,也有许多院校的物理理论课教学受到很大的限制．亟待出台适应新形势、有全国指导意义的医药类专业(本科)物理课程教学基本要求,以利于规范普通高等学校医药类专业(本科)物理课程教学．     

Fiber-optic sensor based on evanescent wave absorbance around 2.7 μm for determining water content in polar organic solvents

The feasibility of sapphire fiber-optic sensors based on evanescent wave absorption spectroscopy in the infrared range for quantitative determination of water content in polar organic solvents has been investigated. Evanescent wave absorption spectra of sapphire fiber-optic sensors in glycerol, ethanol, and glycol with different water concentrations obtained and analyzed, respectively. Evanescent absorbance of the sensors in those organic solvents has been utilized to implement for in situ monitoring water concentration in organic solvents. The evanescent absorbance of sensors in glycerol and glycol has been found to vary linearly with water content in the range 0–30 % and in ethanol in the range 0–10 %, respectively. The fiber-optic sensors based on evanescent absorbance for monitoring water concentrations in those organic solvents are acceptably accurate, cost-effective, and reliable. Some methods to improve the accuracy of predicated water content in those organic solvents are also suggested. Overall, the results demonstrate that the sapphire fiber-optic sensor based on evanescent absorption spectroscopy is a promising candidate for prediction of water content in polar organic solvents in on-line and remote situation.     

Strain-induced interaction of interstitials in IVA group hcp metals

Strain-induced (elastic) interactions of oxygen, nitrogen and carbon atoms in IVA group metals, α-Ti, Zr, and -Hf, are calculated in the framework of the microscopic Krivoglaz-Kanzaki-Khachaturyan theory. The experimental elastic constants, lattice spacing of the host metal, and concentration expansion coefficients are used as the input numerical parameters. The resulting interactions are stronger in α-Ti than in α-Zr and α-Hf. A comparative analysis of interactions in the hcp IVA group metals with those in bcc and fcc solid solutions reveals the crystal structure effect. In general, the strain-induced interactions of O, N, and C in hcp IVA group metals are weaker than in bcc solid solutions and are stronger than in fcc solid solutions.     

Relaxation enhancement using liposomes carrying paramagnetic species

Studies were performed to investigate the effects upon the relaxation times of mouse organs of intravenously administered Mn-DTPA entrapped in multilamellar liposomes, Mn-DTPA, 0.9% NaCl entrapped in liposomes, 0.9% NaCl. Manganese concentrations in injectates and tissues were assessed with 54Mn and atomic absorption. T1 and T2 of freshly excised tissues were measured in an NMR spectrometer at 20 MHz and 37% C with IR and CPMG sequences. Entrapment of Mn-DTPA in liposomes increased 54Mn accumulation in liver by 207% and in spleen 1208% and reduced 54Mn in heart by 20% and in kidney by 24% relative to free Mn-DTPA. Statistically significant increases in relaxation rates were produced. However, the increase in relaxation rate per unit concentration of Mn in tissue is reduced by 31% in liver and 62% in spleen when Mn is delivered inside liposomes. These observations have implications for the design of NMR contrast agents.     

In vivo and in vitro study of porcine oviductal epithelial cells, cumulus oocyte complexes and granulosa cells: a scanning electron microscopy and inverted microscopy study

The morphology and structure of porcine oviductal epithelial cells (POEC), cumulus-oocyte complexes (COCs) and granulosa cells (GC) were investigated in vivo and in vitro conditions using scanning electron microscopy (SEM) and inverted microscopy. The POEC contained columnar ciliated cells and spherical shaped non-ciliated cells. Both non- and ciliated cells appeared either in groups or distributing among each other. However, the isolation of cells was observed after culture for 48 h. A total of 921 oocytes from 20 ovaries was isolated resulting in an average of 46 oocytes per ovary. They were round in shape, surrounded by zona pellucida with layers of cumulus cells ranging between 89.16 and 144.68 μm in size. As for COCs, they were classified into 4 types; intact-, multi-, partial-cumulus cell layers and completely denuded oocyte. Interestingly, changes in morphology of COCs with intact and multi-cumulus cell layers were observed in the in vitro study. The GCs in the follicular fluid were also round in shape and found as clusters. After culturing in in vitro for 48 h, no change in morphology was observed. The GC appeared in smaller clusters or were present as single cells and their sizes ranged from 6 to 8 μm. The results obtained from this study allow us to have a better understanding of the morphology and nature of cells under both in vivo and in vitro conditions. This information is also important for the study of their secretions and biochemical compositions, which is of great importance to the use of cells as feeder cells in in vitro fertilization in current studies.     

Isotope variations in white-tailed kites from various habitats in California: possible limitations in assessing prey utilization and population dynamics

White-tailed kite (Elanus leucurus) populations in the 1930s were close to extirpation in the United States. But by the 1940s, an upward trend towards recovery was apparent and continued to their current stable population levels. These dramatic fluctuations in kite numbers may have been related to changes in rodent prey populations due to the conversion of native habitats to agriculture. To address this question, we evaluated the use of stable isotope analysis in determining if a shift in diet could be isotopically differentiated in current and historic kite populations. We first compared delta13C, delta15N, and delta34S values from present-day kite flight feathers and prey fur samples from four locations in California. The total ranges of isotope values for kite and their rodent prey were similar within each site. Carbon isotope values ranged from -27.1 to -22.2 per thousand in Arcata, -26.1 to -16.9 per thousand in Davis, -27.0 to -15.0 per thousand in Cosumnes, and -28.2 to -11.6 per thousand in Santa Barbara. Nitrogen isotope values ranged from 3.2 to 15.7 per thousand in Arcata, 2.8 to 12.7 per thousand in Davis, 4.0 to 15.7 per thousand in Cosumnes, and 1.7 to 20.0 per thousand in Santa Barbara. Sulfur isotope values ranged from -7.8 to 12.4 per thousand in Arcata, -1.1 to 9.2 per thousand in Davis, 0.7 to 10.9 per thousand in Cosumnes, and -8.6 to 15.6 per thousand in Santa Barbara. Carbon, nitrogen, and sulfur isotope values at each site reflect typical trophic enrichments due to physiological processes. At each site, delta13C and delta15N values reflected the influence of a predominantly C3 or a mixed C3/C4 plant community. Sulfur isotope values reflect the influence of predominant marine or terrestrial sulfur sources at each site. However, variability in isotope values may limit the usefulness of such analyses for addressing prey utilization and population dynamics.     

Fluorescence and Time-Resolved Delayed Luminescence of Porphyrins in Organic Solvents and Polymer Matrices

Porphyrin dyes fulfill an essential function in photosynthesis and are important in photodynamic therapy and in a range of electronic devices. Their spectroscopic characteristics may play a crucial role in these processes. The spectral properties of two porphyrin dyes: tetraphenylporphyrin and tetraphenysulfporphyrin in organic solvents (acetone, chloroform, methyl alcohol, and dimethyl-sulfoxide) and in polyvinyl alcohol and poly(methylmethacrylate) films have been investigated. Absorption, fluorescence, and microsecond time-resolved delayed luminescence spectra have been measured at room temperature. The existence of different aggregated dye forms in the ground and excited states has been demonstrated. The manifold of dye species depends on the solvent/polymer. In the case of the polymers, it also depends on the solvent used to coat the polymer film. Delayed luminescence spectra and decay times of the two porphyrins in the different solutions and in polymeric matrices suggest that different mechanisms of deexcitation of the singlet excited states may be responsible for their generation in these and other porphyrin dyes.     

COMPARISON OF COMMUNITY RESPONSE TO ROAD TRAFFIC NOISE IN JAPAN AND SWEDEN—PART I: OUTLINE OF SURVEYS AND DOSE-RESPONSE RELATIONSHIPS

To investigate cross-cultural differences in the community response to road traffic noise, social surveys were conducted in Gothenburg, Sweden, and Kumamoto and Sapporo, Japan, using the same questionnaire and noise measurement method. Typical residential areas with detached houses and apartments were selected as the target areas in each city. The questionnaire comprised 40 questions relating to environmental, housing and personal factors. The key questions concerned annoyance caused by road traffic noise. The total numbers of respondents were 1142 in Gothenburg, 837 in Kumamoto and 780 in Sapporo. The response rates were 68·8, 69·3 and 57·5% respectively. After the questionnaires were completed, noise measurements were made in each area. Community responses were compared on the basis of the dose-response relationships. There were no systematic differences between community responses in Sapporo and Kumamoto, which have the same culture. People living in detached houses in Gothenburg were more annoyed by the same road traffic noise than the people living in Japanese cities. There were no systematic differences among the three cities with regard to activity disturbances indoors, but significant disturbance of activities and resting in gardens or on balconies was noted in Gothenburg. The difference in activity disturbance was due to the differences between lifestyles in the two countries. People living in detached houses were more annoyed by the house vibration caused by road traffic than those living in apartments and people were annoyed by the exhaust from road traffic to the same extent as noise.