电感耦合等离子体质谱法测定高纯镉中的杂质元素

采用电感耦合等离子体质谱法测定高纯镉中的杂质元素。讨论了镉基体的谱线干扰，比较了镉基体产生的多原子离子的干扰程度，该干扰按Cdh、CdO、CdO2、CdAr、CdOH和CdOH2顺序递减。研究了不同浓度镉基体对分析物信号的抑制或增强效应，镉的浓度大于0.25·L-1时，对质量数小于100的分析物的信号强度产生抑制，而对质量数大于150的分析物的信号强度产生增强，采用89Y和209Bi作内标分别克服基体的抑制和增强效应。测定了高纯镉的As、Be、Co、Cu、Ga、Ge、Mn、Mo、Pb、Ni、Sr、Au、Tl、Th、V和U等16个杂质元素，方法的检测限0.005～0.052μｇ·L-1，标准加入回收率82%～108%。

牙鲆生长相关性状遗传力估计

遗传力是数量遗传学的重要参数，对鱼类良种选育具有重要意义。可靠的遗传力估计值可以为合理制定育种计划提供宝贵信息，同时可以预测选择反应。本文按照10×3因子设计方法，10尾雄鱼与3尾雌鱼两两授精，产生10个父系半同胞、3个母系半同胞及30个全同胞家系，以微卫星分子标记为家系鉴定手段，对40日龄牙鲆生长相关性状遗传力进行了估计；同时，初步探讨了因子交配设计及人工控制条件下，亲本对子代遗传贡献率差异及有效群体大小。主要结论包括：1.初步筛选的14个微卫星位点中，有9个（Po91、Po1、Po56、Po20、Poli23、Po89、Poli121、Po42、Po13）在亲本中呈现中、高度多态性：平均等位基因9.4个；平均亲本特异性等位基因4个。用5个位点（Po91、Po1、Po56、Po20、Poli23）为346个子代中的227个个体找到所属家系；继续用另外4个位点（Po89、Poli121、Po42、Po13）分型，成功鉴定72个个体。鉴定率约86%，其中，亲本特异性等位基因的存在使鉴定效率大大提高。以上9个位点可为该群体良种选育工作提供技术支持。2. 发生降解的DNA与完整的DNA，在相同引物、相同PCR体系、相同模板浓度下扩增的带型一致。该结果证实了微卫星分型对降解的DNA同样稳定。3. 亲本对子代的遗传贡献率存在差异。雄亲的贡献率为5.8—14.3%，除3号、9号子代数较少，5号、6号子代数较多外，其它父本基本一致；母本对子代的贡献率差异较大（18.5%—50.6%），这与人工授精前雌亲发育状况、卵子质量检测结果基本一致，在一定程度上说明，母本尤其是卵子质量对鱼类早期存活具有较大影响。4. 家系内子代数目的不平衡导致实际有效群体大小下降。Ne=7.44，比理论有效群体大小（9.23）下降约19%。但与自然交配相比（有效群体下降可达75%），人工控制下的交配在一定程度上可有效限制遗传多样性的下降。5. 基于父本方差组分，40日龄生长相关性状遗传力估计值（h2s±S.E.）为（0.157±0.052）－（0.440±0.137）。加性遗传方差在表型方差中所占的比例，在一定程度上表明该牙鲆群体生长性状具有一定的选择力度。

海北高寒草甸生态系统定位站辐射气候特征

以2000—03到2001—02的辐射观测资料，分析了海北高寒草甸生态系统定位站地区辐射及各分光辐射的变化特征．将为高寒草甸生态系统的物质循环、能量流动、草地生产力形成机制等问题的研究提供科学依据。结果表明：海北站区Eg、Er、UV、PAR、NIR和En具有明显的日、年变化，年内其总量分别达6278．867MJ／m^2、1515．139MJ／m^2、311．242MJ／m^2、2576．777MJ／m^2、3397．404MJ／m^2和2542．950MJ／m^2，其中在植物生长期的5—9月分别为3181．215MJ／m^2、698．021MJ／m^2、165．955MJ／m^2、1133．965MJ／m^2、1673．871MJ／m^2和1668．805MJ／m^2。年内Er、UV、PAR、NIR和Eh占Eg的比例分别为0．242、0．048、0．410、0．540和0．410，在植物生长期分别为0．219、0．052、0．413、0.528和0．527。对Eg和PAR提出了下列形式的模拟求算式．Eg=Eg0（0．089．7＋0．9768S／S0）和PAR=-3.8044＋0.4177％，模拟效果较好，可利用有关常规气象观测资料进行估算。

祁连山海北高寒草甸地区紫外辐射特征及其对植物生理作用的探讨

利用祁连山海北高寒草甸地区2000年植物生长期内的太阳辐射观测资料，分析了该地区太阳紫外辐射(UV)在植物生长期内的日、季节变化特征，以及在太阳总辐射(E_g)中所占的比例(η)。结果表明：海北站地区UV较强，瞬时极大值可达77 W·m~(-2)，日总量最大达1.8 MJ·m~(-2)以上；实际天气状况下月总量最大可达41.620 MJ·m~(-2) (5月)，植物生长期内的4月到10月总量达218.651 MJ·m~(-2)。UV有明显的日、季节变化规律。日间UV所表现的单峰式曲线变化过程，与总辐射变化有关。在晴天状况下，η的变化下午高于上午，日平均约为0.048；阴天状况下在13:00～14:00较高，早晚低，且随云层厚薄而发生显著的变化。同时表明，阴天状况下的η值(0.053)高于晴天。就生长期实际情况来看，η值在植物生长的前期较高，植物生长后期较低，植物生长期内平均约为0.052。受强UV的影响，高寒草甸几种主要植物，其植物根、茎、叶的可溶性糖含量、淀粉含量、非结构性碳水化合物均较高，且表现出日出后迅速增加，植物根茎粗壮等，植物的生理适应性及其植物体的结构发生改变，致使高寒草甸植物具有明显的抗寒性功能机制和形态结构。

河西走廊棘豆毒草中的硒及其与牲畜中毒关系研究

河西走廊地区草原生态环境,棘豆等毒草泛滥成灾,导致大量牲畜中毒死亡。棘豆毒草导致的牲畜中毒症状与历史上马可波罗记载的古代肃州牲畜毒草中毒症状及其相似。为了确定马可波罗所记载的肃州牲畜毒草中毒是否与硒有关,本项研究对河西走廊地区主要草原畜牧区肃南县草原发育的棘豆属植物及其土壤中的硒进行了测定,测定结果表明:土壤硒含量平均值为0.205±0.173mg/kg,与世界平均土壤硒含量相近。棘豆属植物小花棘豆根、茎叶的硒平均含量分别为0.112±0.038mg/kg(0.052～0.174mg/kg),0.102±0.027mg/kg(0.066～0.158 mg/kg);黄花棘豆全株硒平均含量为0.066±0.009mg/kg(0.058～0.078mg/kg),种子硒:0.107mg/kg。可见该区棘豆属毒草硒含量远低于能导致一般动物中毒的3mg/kg植物硒含量。根据肃南县棘豆毒草发育的地理位置、牲畜中毒症状调查及其硒含量测定的结果,本文认为马可波罗所记载的中国西部肃州牲畜毒草中毒是棘豆属毒草中毒,其主要毒素成分不是硒。

贵阳市大气总悬浮颗粒物(TSP)的化学特征及其影响因素研究

气溶胶对气候和人类的健康都有重要影响。因此，研究大气总悬浮颗粒物（TSP）的化学组成和物理特性对更深入地了解气溶胶对气候和人类健康的影响具有重要意义。贵阳是中国受燃煤污染比较严重的城市之一，大气中高含量的SO2是其最明显的特征。尽管最近几年空气质量有所改善，但是该区的大气污染问题还比较严重，空气质量仍然不容乐观。我们于2005年1月1日到2005年12月31日在中科院地球化学研究所内全年采集总悬浮颗粒物（TSP）样品，分析测试了其主要无机离子（F-、Cl-、SO42-、NO3-、NH4+、K+、Na+、Ca2+和Mg2+）的化学性质，并结合当地的气象参数（温度，风速，降雨量和相对湿度）系统地研究了TSP及其水溶性无机离子的季节变化特征。本论文的主要结论有： 1. TSP的浓度变化范围为36.91～313.44µg/m3，年均值106.60µg/m3；各离子摩尔浓度的大小顺序为：SO42-> NH4+> Ca2+ > NO3-> K+ > Na+ > Cl- > Mg2+ > F-；SO42- (23.04±12.16µg/m3)和NH4+(3.05±2.23µg/m3)是最主要的离子，分别占总离子摩尔数的37％和30％。TSP及其组分都有明显的季节变化，TSP、Cl-、SO42-、NO3-、NH4+、K+、Na+、Ca2+和Mg2+浓度的冬/夏比值分别为:1.29、5.23、1.35、2.37、1.73、1.22、1.84、1.23和1.02。 2. 温度对TSP及其水溶性无机组分的影响呈现一定的季节变化模式，冬天随温度的升高TSP及其水溶无机组分的浓度也升高，夏天随温度的升高TSP及其水溶性无机组分的浓度降低。但是从全年来看，温度与TSP及其水溶性无机组分之间有弱的负相关性，即随温度的升高，TSP及其水溶性无机组分的浓度有不同程度的下降。相对湿度与TSP及其水溶性无机组分之间存在明显的负相关关系，即随大气相对湿度的增加，TSP及其水溶性无机组分的浓度下降。在相对湿度与TSP及其水溶性无机组分浓度的日变化图中表现为相对湿度的波谷与TSP及其水溶无机组分的浓度的波峰相对应。风速与TSP及其水溶无机组分的浓度之间呈现弱的负相关性。在贵阳，风速对TSP及其水溶无机组分的影响主要表现为扩散作用和稀释作用，由风速导致的尘土再悬浮作用并不明显。雨量对TSP及其水溶性无机组分的影响主要是湿清除作用，具体表现为无雨天TSP及其水溶性无机组分的浓度较雨天高。影响TSP、Ca2+、Mg2+和F-的主要气象参数是相对湿度(RH)和风速，影响SO42-、NO3-、NH4+和Cl-的主要气象参数是温度。 3. 贵阳大气总悬浮颗粒物（TSP）总体偏酸性，TSP水溶液pH值的年均值为6.27±0.41，与总阴离子与总阳离子的当量比Q的年平均值为0.82一致；TSP中高含量的SO42-是贵阳的TSP显酸性的主要原因。 4. NH4+与SO42-和NO3-的相关系数（R）分别为0.85和0.65，NH4+与SO42-的摩尔比值为0.8，说明贵阳TSP中的NH4+主要以(NH4)2SO4的形式存在。Ca2+和Mg2+有较好的相关性（R=0.72）和相似的变化特征，说明二者可能有共同的来源。 5. 2005年贵阳TSP中SO42-/ Ca2+的平均值为13.64，几乎是干净大陆SO42-/ Ca2+的本底值的20倍，说明贵阳的大气污染主要是人为因素所致。NO3-/SO42-的平均值为0.15，说明固定源对贵阳气溶胶的贡献比移动源（通常指交通工具所排放的尾气）对气溶胶的贡献大；

Volume-Time Curve: An Alternative for Endotracheal Tube Cuff Management

BACKGROUND: Despite numerous studies on endotracheal tube cuff pressure (CP) management, the literature has yet to establish a technique capable of adequately tilling the cuff with an appropriate volume of air while generating low CP in a less subjective way. the purpose of this prospective study was to evaluate and compare the CP levels and air volume required to fill the endotracheal tubes cuff using 2 different techniques (volume-time curve versus minimal occlusive volume) in the immediate postoperative period after coronary artery bypass grafting. METHODS: A total of 267 subjects were analyzed. After the surgery, the lungs were ventilated using pressure controlled continuous mandatory ventilation, and the same ventilatory parameters were adjusted. Upon arrival in the ICU, the cuff was completely deflated and re-inflated, and at this point the volume of air to fill the cuff was adjusted using one of 2 randomly selected techniques: volume-time curve and minimal occlusive volume. We measured the volume of air injected into the cuff, the CP, and the expired tidal volume of the mechanical ventilation after the application of each technique. RESULTS: the volume-time curve technique demonstrated a significantly lower CP and a lower volume of air injected into the cuff, compared to the minimal occlusive volume technique (P < .001). No significant difference was observed in the expired tidal volume between the 2 techniques (P = .052). However, when the subjects were submitted to the minimal occlusive volume technique, 17% (n = 47) experienced air leakage as observed by the volume-time graph. CONCLUSIONS: the volume-time curve technique was associated with a lower CP and a lower volume of air injected into the cuff, when compared to the minimal occlusive volume technique in the immediate postoperative period after coronary artery bypass grafting. Therefore, the volume-time curve may be a more reliable alternative for endotracheal tube cuff management.

Xanthine oxidase pathway and muscle damage: Insights from McArdle disease

The intent of this review is to summarize current body of knowledge on the potential implication of the xanthine oxidase pathway (XO) on skeletal muscle damage. The possible involvement of the XO pathway in muscle damage is exemplified by the role of XO inhibitors (e.g., allopurinol) in attenuating muscle damage. Reliance on this pathway (as well as on the purine nucleotide cycle) could be exacerbated in conditions of low muscle glycogen availability. Thus, we also summarize current hypotheses on the etiology of both baseline and exertional muscle damage in McArdle disease, a condition caused by inherited deficiency of myophosphorylase. Because myophosphorylase catalyzes the first step of muscle glycogen breakdown, patients are unable to obtain energy from their muscle glycogen stores. Finally, we provide preliminary data from our laboratory on the potential implication of the XO pathway in the muscle damage that is commonly experienced by these patients.

Biological rationale for regular physical exercise as an effective intervention for the prevention and treatment of depressive disorders

Depression is a major medical and social problem. Here we review current body of knowledge on the benefits of exercise as an effective strategy for both the prevention and treatment of this condition. We also analyze the biological pathways involved in such potential benefits, which include changes in neurotrophic factors, oxidative stress and inflammation, telomere length, brain volume and microvessels, neurotransmitters or hormones. We also identify major caveats in this field of research: further studies are needed to identify which are the most appropriate types of exercise interventions (intensity, duration, or frequency) to treat and prevent depression.

Fusion ARTMAP: An Adaptive Fuzzy Network for Multi-Channel Classification

Fusion ARTMAP is a self-organizing neural network architecture for multi-channel, or multi-sensor, data fusion. Fusion ARTMAP generalizes the fuzzy ARTMAP architecture in order to adaptively classify multi-channel data. The network has a symmetric organization such that each channel can be dynamically configured to serve as either a data input or a teaching input to the system. An ART module forms a compressed recognition code within each channel. These codes, in turn, beco1ne inputs to a single ART system that organizes the global recognition code. When a predictive error occurs, a process called parallel match tracking simultaneously raises vigilances in multiple ART modules until reset is triggered in one of thmn. Parallel match tracking hereby resets only that portion of the recognition code with the poorest match, or minimum predictive confidence. This internally controlled selective reset process is a type of credit assignment that creates a parsimoniously connected learned network.

Comparative performance of multiview stereoscopic and mammographic display modalities for breast lesion detection.

PURPOSE: Mammography is known to be one of the most difficult radiographic exams to interpret. Mammography has important limitations, including the superposition of normal tissue that can obscure a mass, chance alignment of normal tissue to mimic a true lesion and the inability to derive volumetric information. It has been shown that stereomammography can overcome these deficiencies by showing that layers of normal tissue lay at different depths. If standard stereomammography (i.e., a single stereoscopic pair consisting of two projection images) can significantly improve lesion detection, how will multiview stereoscopy (MVS), where many projection images are used, compare to mammography? The aim of this study was to assess the relative performance of MVS compared to mammography for breast mass detection. METHODS: The MVS image sets consisted of the 25 raw projection images acquired over an arc of approximately 45 degrees using a Siemens prototype breast tomosynthesis system. The mammograms were acquired using a commercial Siemens FFDM system. The raw data were taken from both of these systems for 27 cases and realistic simulated mass lesions were added to duplicates of the 27 images at the same local contrast. The images with lesions (27 mammography and 27 MVS) and the images without lesions (27 mammography and 27 MVS) were then postprocessed to provide comparable and representative image appearance across the two modalities. All 108 image sets were shown to five full-time breast imaging radiologists in random order on a state-of-the-art stereoscopic display. The observers were asked to give a confidence rating for each image (0 for lesion definitely not present, 100 for lesion definitely present). The ratings were then compiled and processed using ROC and variance analysis. RESULTS: The mean AUC for the five observers was 0.614 +/- 0.055 for mammography and 0.778 +/- 0.052 for multiview stereoscopy. The difference of 0.164 +/- 0.065 was statistically significant with a p-value of 0.0148. CONCLUSIONS: The differences in the AUCs and the p-value suggest that multiview stereoscopy has a statistically significant advantage over mammography in the detection of simulated breast masses. This highlights the dominance of anatomical noise compared to quantum noise for breast mass detection. It also shows that significant lesion detection can be achieved with MVS without any of the artifacts associated with tomosynthesis.

Spin three gauge theory revisited

We study the problem of consistent interactions for spin-3 gauge fields in flat spacetime of arbitrary dimension 3$">n>3. Under the sole assumptions of Poincaré and parity invariance, local and perturbative deformation of the free theory, we determine all nontrivial consistent deformations of the abelian gauge algebra and classify the corresponding deformations of the quadratic action, at first order in the deformation parameter. We prove that all such vertices are cubic, contain a total of either three or five derivatives and are uniquely characterized by a rank-three constant tensor (an internal algebra structure constant). The covariant cubic vertex containing three derivatives is the vertex discovered by Berends, Burgers and van Dam, which however leads to inconsistencies at second order in the deformation parameter. In dimensions 4$">n>4 and for a completely antisymmetric structure constant tensor, another covariant cubic vertex exists, which contains five derivatives and passes the consistency test where the previous vertex failed. © SISSA 2006.

Expression of the Ets transcription factor Erm is regulated through a conventional PKC signaling pathway in the Molt4 lymphoblastic cell line.

Erm, a member of the PEA3 group within the Ets family of transcription factors, is expressed in murine and human lymphocytes. Here, we show that in the human Molt4 lymphoblastic cell line, the erm gene expression is regulated by the conventional PKC (cPKC) pathway. To better characterize the molecular mechanism by which cPKC regulates Erm transcription in Molt4 cells, we tested proximal promoter deletions of the human gene, and identified a specific cPKC-regulated region between positions -420 and -115 upstream of the first exon.

Creativity and entrepreneurial efforts in an emerging economy

While much research has focused on entrepreneurship and creativity in developed economies, the notions of both topics are still embryonic in many emerging economies. This paper focuses on entrepreneurs in one such economy, Vietnam, to understand the perceptions of entrepreneurs about the role that innovation and creativity may play in their own entrepreneurial ventures and success. This is important because before reaping benefits from entrepreneurship, entrepreneurs need to decide when and on what conditions they start based on their calculations of required resources and predictions of likely outcomes. The research also sought to understand how "creativity," broadly applied ("innovation" and "creative performance") affects the ways that entrepreneurs think about and anticipate their own success and decisions. In essence, the study suggests that the higher the entrepreur’s creativity is, the more likely she or he is to start a new business and believe success will result. Future research could examine whether history, industry and geographic location matter in entrepreneurs’ perceptions as well as whether transition/emerging economies like Vietnam may have different views altogether about the two key concepts.

The effects of cadence and power output upon physiological and biomechanical responses to incremental arm-crank ergometry

The aim of this study was to examine the effects of cadence and power output on physiological and biomechanical responses to incremental arm-crank ergometry (ACE). Ten male subjects (mean +/- SD age, 30.4 +/-5.4 y; height, 1.78 +/-0.07 m; mass, 86.1 +/-14.2 kg) undertook 3 incremental ACE protocols to determine peak oxygen uptake (VO2 peak; mean of 3 tests: 3.07 +/- 0.17 L.min-1) at randomly assigned cadences of 50, 70, or 90 r.min-1. Heart rate and expired air were continually monitored. Central (RPE-C) and local (RPE-L) ratings of perceived exertion were recorded at volitional exhaustion. Joint angles and trunk rotation were analysed during each exercise stage. During submaximal power outputs of 50, 70, and 90 W, oxygen consumption (VO2) was lowest for 50 r.min-1 and highest for 90 r.min-1 (p < 0.01). VO2 peak was lowest during 50 r.min-1 (2.79 +/-0.45 L.min-1; p < 0.05) when compared with both 70 r.min-1 and 90 r.min-1 (3.16 +/-0.58, 3.24 +/-0.49 L.min-1, respectively; p > 0.05). The difference between RPE-L and RPE-C at volitional exhaustion was greatest during 50 r.min-1 (2.9 +/- 1.6) when compared with 90 r.min-1 (0.9 +/- 1.9, p < 0.05). At VO2 peak, shoulder range of motion (ROM) and trunk rotation were greater for 50 and 70 r.min-1 when compared with 90 r.min-1 (p < 0.05). During submaximal power outputs, shoulder angle and trunk rotation were greatest at 50 r.min-1 when compared with 90 r.min-1 (p < 0.05). VO2 was inversely related to both trunk rotation and shoulder ROM during submaximal power outputs. The results of this study suggest that the greater forces required at lower cadences to produce a given power output resulted in greater joint angles and range of shoulder and trunk movement. Greater isometric contractions for torso stabilization and increased cost of breathing possibly from respiratory-locomotor coupling may have contributed increased oxygen consumption at higher cadences.