BACKGROUND & AIMS: :The magnitude of inbreeding depression in small populations may depend on the effectiveness with which natural selection purges deleterious recessive alleles from populations during inbreeding. The effectiveness of this purging process, however, may be influenced by the rate of inbreeding and the environment in which inbreeding occurs. Although some experimental studies have examined these factors individually, no study has examined their joint effect or potential interaction. In the present study, therefore, we performed an experiment in which 180 lineages of Drosophila melanogaster were inbred at slow and fast inbreeding rates within each of three inbreeding environments (benign, high temperature, and competitive). The fitness of all lineages was then measured in a common benign environment. Although slow inbreeding reduced inbreeding depression in lineages inbred under high temperature stress, a similar reduction was not observed with respect to the benign or competitive treatments. Overall, therefore, the effect of inbreeding rate was nonsignificant. The inbreeding environment, in contrast, had a larger and more consistent effect on inbreeding depression. Under both slow and fast rates of inbreeding, inbreeding depression was significantly reduced in lineages inbred in the presence of a competitor D. melanogaster strain. A similar reduction of inbreeding depression occurred in lineages inbred under high temperature stress at a slow inbreeding rate. Overall, our findings show that inbreeding depression is reduced when inbreeding takes place in a stressful environment, possibly due to more effective purging under such conditions.

背景与目标： ：小种群中近交抑郁的严重程度可能取决于自然选择在近交过程中清除种群中有害的隐性等位基因的有效性。然而，该吹扫过程的有效性可能受到近交率和近交发生环境的影响。尽管一些实验研究单独检查了这些因素，但没有研究检查它们的联合作用或潜在的相互作用。因此，在本研究中，我们进行了一项实验，其中在三个近交环境（良性，高温和竞争性）中，分别以慢速和快速近交率近交了180个果蝇果蝇。然后在一个普通的良性环境中测量所有血统的适应性。尽管缓慢的近交减少了在高温胁迫下近交的血统的近交衰退，但在良性或竞争性处理方面未观察到类似的减少。因此，总的来说，近交率的影响不显着。相反，近交环境对近交抑郁症具有更大和更一致的影响。在近交速度和近交速度下，在存在竞争性D. melanogaster毒株的情况下，近交沮丧感在自交系谱系中均显着降低。在高温胁迫下以近交速率缓慢繁殖的近亲谱系发生了近交抑制的相似减少。总体而言，我们的研究结果表明，在压力环境中进行近亲繁殖时，近亲凹陷减少了，这可能是由于在这种条件下进行更有效的清除所致。

BACKGROUND & AIMS: :The objective of this study was to examine the psychometric properties of the Invalidating Childhood Environment Scale (ICES; Mountford, Corstorphine, Tomlinson, & Waller, 2004), a measure designed to retrospectively assess exposure to parental invalidation. The ICES was administered to a sample of female college students along with measures of parental bonding and borderline personality disorder (BPD) symptomatology. In contrast with previous findings, the ICES demonstrated excellent internal consistency within a nonclinical sample. It also correlated in the predicted directions with measures of parental bonding and BPD symptomatology. Taken together, these findings suggest that the ICES is a promising retrospective measure of parental invalidation. They also provide some support for the hypothesized link between parental invalidation and BPD symptomatology and suggest that additional research with clinical samples is needed.

背景与目标： ：这项研究的目的是检验儿童期无效环境量表（ICES； Mountford，Corstorphine，Tomlinson和Waller，2004年）的心理计量学特性，该措施旨在回顾性评估父母对父母的无效性的暴露程度。将ICES应用于女大学生样本，并测量父母亲和性和边缘性人格障碍（BPD）症状的测量结果。与以前的发现相反，ICES在非临床样品中显示出优异的内部一致性。它还在预测的方向上与父母亲结合和BPD症状的测量相关。综上所述，这些发现表明，ICES是一种有前途的回顾性父母无效检查方法。他们还为父母无效与BPD症状之间的假设联系提供了一些支持，并建议需要对临床样本进行更多研究。

BACKGROUND & AIMS: The moment-to-moment processing of information by the nervous system involves the propagation and interaction of electrical and chemical signals that are distributed in space and time. Biologically realistic modeling is needed to test hypotheses about the mechanisms that govern these signals and how nervous system function emerges from the operation of these mechanisms. The NEURON simulation program provides a powerful and flexible environment for implementing such models of individual neurons and small networks of neurons. It is particularly useful when membrane potential is nonuniform and membrane currents are complex. We present the basic ideas that would help informed users make the most efficient use of NEURON.

背景与目标： 神经系统对信息的从瞬间到瞬间的处理涉及在空间和时间上分布的电信号和化学信号的传播和相互作用。需要生物学上逼真的建模来检验关于控制这些信号的机制以及这些机制的运作如何产生神经系统功能的假设。 NEURON仿真程序为实施单个神经元和小型神经元网络的模型提供了强大而灵活的环境。当膜电位不均匀且膜电流复杂时，此功能特别有用。我们提出了一些基本思路，可以帮助有经验的用户最有效地使用NEURON。

BACKGROUND & AIMS: PURPOSE:The purpose of this study was twofold: (a) to assess predictors of the turnover intention, burnout, and perceived quality of care among nurses working in Oman, and (b) to examine the potential moderating role of job satisfaction on the relationship between work environment and nurse turnover intention. DESIGN:A cross-sectional design was used to collect data from a sample of 207 nurses working in a public hospital in Muscat, Oman. METHODS:An electronic survey was used to assess nurses' perceptions of work environment, burnout, job satisfaction, turnover intention, and quality of care. FINDINGS:Participation in hospital affairs, a foundation for quality of care, and staffing adequacy were predictors of burnout among nurses and perceived quality of care. Logistic regression analysis revealed that working in a favorable environment was associated with less turnover intention, but only when job satisfaction was high. CONCLUSIONS:Improving nurse job satisfaction is a mechanism through which future interventions could enhance working conditions and promote better nurse retention. CLINICAL RELEVANCE:Organizational strategies are needed to increase nurse job satisfaction by empowering nurses to take more active roles in hospital affairs as a strategy to reduce turnover intention and enhance the quality of patient care.

背景与目标： 目的：本研究的目的是双重的：（a）评估在阿曼工作的护士的离职意向，倦怠和感知的护理质量的预测因子，以及（b）检验工作满意度对这种关系的潜在调节作用工作环境和护士离职意图之间的关系。
设计：采用横断面设计从阿曼马斯喀特一家公立医院工作的207名护士的样本中收集数据。
方法：采用电子调查来评估护士对工作环境，职业倦怠，工作满意度，离职意向和护理质量的看法。
结果：参与医院事务，护理质量的基础和人员配备充足是护士倦怠和感知护理质量的预测指标。 Logistic回归分析显示，在有利的环境中工作与离职意愿降低有关，但只有在工作满意度高的情况下才可以。
结论：提高护士的工作满意度是一种机制，通过该机制，未来的干预措施可以改善工作条件并促进更好的护士留任率。
临床相关性：需要组织战略来增强护士的工作满意度，使护士能够在医院事务中发挥更积极的作用，以此作为减少离职意向和提高患者护理质量的战略。

BACKGROUND & AIMS: :Primary liver cancer, consisting predominantly of hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), remains one of the most lethal malignancies worldwide. This high malignancy is related to the complex and dynamic interactions between tumour cells, stromal cells and the extracellular environment. Novel in vitro models that can recapitulate the tumour are essential in increasing our understanding of liver cancer. Herein, primary liver cancer-derived organoids have opened up new avenues due to their patient-specificity, self-organizing ability and potential recapitulation of many of the tumour properties. Organoids are solely of epithelial origin, but incorporation into co-culture models can enable the investigation of the cellular component of the tumour microenvironment. However, the extracellular component also plays a vital role in cancer progression and representation is lacking within current in vitro models. In this review, organoid technology is discussed in the context of liver cancer models through comparisons to other cell culture systems. In addition, the role of the tumour extracellular environment in primary liver cancer will be highlighted with an emphasis on its importance in in vitro modelling. Converging novel organoid-based models with models incorporating the native tumour microenvironment could lead to experimental models that can better recapitulate liver tumours in vivo.

背景与目标： 原发性肝癌主要由肝细胞癌（HCC）和胆管癌（CCA）组成，仍然是全球最致命的恶性肿瘤之一。这种高恶性与肿瘤细胞，基质细胞和细胞外环境之间复杂而动态的相互作用有关。可以概括肿瘤的新型体外模型对于增进我们对肝癌的了解至关重要。在本文中，原发性肝癌衍生的类器官由于其患者特异性，自组织能力和许多肿瘤特性的潜在概括而开辟了新途径。类器官仅是上皮来源的，但是掺入共培养模型可以研究肿瘤微环境的细胞成分。但是，细胞外成分在癌症进展中也起着至关重要的作用，目前的体外模型中缺乏这种表现形式。在这篇综述中，通过与其他细胞培养系统进行比较，在肝癌模型的背景下讨论类器官技术。另外，将强调肿瘤细胞外环境在原发性肝癌中的作用，并强调其在体外建模中的重要性。将基于类器官的新型模型与结合了天然肿瘤微环境的模型进行融合，可以产生能够更好地在体内概括肝肿瘤的实验模型。

BACKGROUND & AIMS: :The number of primordial germ cells (PGC) in albino tadpoles of Xenopus is significantly decreased as compared with that of the wild-type. Whether the decreased number of PGC is caused by the presumptive PGC (pPGC) themselves or the micro-environment surrounding those cells in the albino, or both was investigated in the present study. [3H]thymidine-labeled pPGC of wild-type and albino were implanted into unlabeled, host neurulae of wild-type or albino and wild-type, respectively. Labeled PGC in the genital ridges of experimental tadpoles were examined by autoradiography. There were no significant differences in the proportion of tadpoles with labeled PGC and in the average number of those PGC between the albino and wild-type tadpoles, into which wild-type pPGC had been implanted. The proportion in wild-type tadpoles with albino pPGC was much lower than that in wild-type tadpoles with wild-type pPGC. These results suggest that the pPGC of the albino and not the micro-environment are responsible for the decreased number of PGC.

背景与目标： ：与野生型相比，非洲爪蟾的白化t中原始生殖细胞（PGC）的数量明显减少。在本研究中，研究了PGC数量减少是由推测的PGC（pPGC）本身还是由白化病中那些细胞周围的微环境引起，还是两者都有。 [3 H]胸苷标记的野生型和白化病的pPGC分别植入未标记的，野生型或白化病和野生型的宿主神经元中。通过放射自显影检查实验t生殖脊中的标记PGC。植入了野生型pPGC的白化病和野生型between之间，带有标记的PGC的t比例和平均PGC数无显着差异。白化病pPGC的野生型ad的比例远低于白化病pPGC的野生型proportion的比例。这些结果表明，白化病的pPGC而不是微环境是造成PGC数量减少的原因。

BACKGROUND & AIMS: :Radiocaesium-bearing microparticles (CsMPs), which are substantially silicate glass, were formed inside the damaged reactor and released to the environment by the Fukushima Dai-ichi Nuclear Power Plant accident in March 2011. The present study reports several valuable findings regarding their composition and structure using advanced microanalytical techniques. X-ray absorption near-edge structure of Fe L3-absorption indicated that the oxidation state of the iron dissolved in the glass matrix of the CsMPs was originally nearly divalent, suggesting that the atmosphere in which the CsMPs were formed during the accident was considerably reductive. Another major finding is that sodium, which has not been recognised as a constituent element of CsMPs thus far, is among the major elements in the glass matrix. The atomic percent of Na is higher than that of other alkali elements such as K and Cs. Furthermore, halite (NaCl) was found as an inclusion inside a CsMP. The existence of Na in CsMPs infers that seawater injected for cooling might reach the inside of the reactor before or during the formation of the CsMPs. These results are valuable to infer the environment inside the reactor during the accident and the debris materials to be removed during the decommissioning processes.

背景与目标： ：含放射性铯的微粒（CsMP），基本上是硅酸盐玻璃，在受损的反应堆内形成，并于2011年3月的福岛第一核电站事故释放到环境中。本研究报告了有关其成分的一些有价值的发现和结构使用先进的微观分析技术。 X射线吸收的Fe L3吸收的近边缘结构表明，溶解在CsMPs玻璃基质中的铁的氧化态原本几乎是二价的，这表明事故期间形成CsMPs的气氛具有相当大的还原性。 。另一个主要发现是，钠（迄今为止尚未被认为是CsMPs的组成元素）是玻璃基质中的主要元素。 Na的原子百分比高于其他碱性元素（例如K和Cs）的原子百分比。此外，发现盐酸盐（NaCl）作为CsMP中的夹杂物。 CsMPs中Na的存在推断为冷却而注入的海水可能在CsMPs形成之前或期间到达反应器内部。这些结果对于推断事故期间反应堆内部的环境以及在退役过程中要清除的碎屑材料很有用。

BACKGROUND & AIMS: :While the nephrology nursing shortage persists despite the continued growth of the population of individuals with Stage 5 chronic kidney disease, there is a paucity of empirical data regarding nephrology nurses' perceptions of their work environments. Moreover, there are no studies that have examined the relationship of work environment attributes to patient and nurse outcomes in dialysis settings. The purpose of this study was to examine the relationships between staff nurses' perceptions of dialysis work environments, nurses' intentions to leave their current jobs, nurse turnover, patient satisfaction, and patient hospitalization rates. A descriptive, correlational design was used. Nurse level and facility level data were obtained. The sample for nurse-level data consisted of 199 registered nurses in staff nurse roles in 56 dialysis facilities of a national dialysis company. The sample for facility-level analysis consisted of 46 dialysis facilities, and nurse-level data were aggregated for facility-level analysis. The Practice Environment Scale-Nursing Work Index (PES-NWI) was used to measure nurses' perceptions of the dialysis work environment. Nurses' intention to leave their jobs and facility-level turnover rates were the nurse outcomes examined in this study. Facility-level patient satisfaction and hospitalization rates were the patient outcomes examined. Correlation coefficients were computed to measure the relationships between study variables, and independent t-tests were performed to examine subgroup differences in work environment perceptions. Overall, nurses rated the work environment somewhat favorably. Nurses who expressed intention to leave their jobs rated the work environment more negatively compared to nurses who intended to stay. Significant correlations were found between nurses' perceptions of the dialysis work environment, nurses' intention to leave their jobs, nurse turnover rates, and patient hospitalizations. Study findings suggest that nurses' perceptions of the dialysis work environment are important for nurse and patient outcomes in dialysis settings. Further research is needed to explore the predictive ability of the work environment for nurse and patient outcomes in hemodialysis units.

背景与目标： ：尽管尽管患有5期慢性肾脏病的人数不断增长，但肾脏科护士短缺仍然存在，但是关于肾脏科护士对其工作环境的看法的经验数据很少。此外，尚无研究检查透析环境中工作环境属性与患者和护士结局之间的关系。这项研究的目的是检验护士对透析工作环境的看法，护士离开当前工作的意图，护士离职率，患者满意度和患者住院率之间的关系。使用了描述性的相关设计。获得了护士级别和设施级别的数据。护士级别数据的样本包括在一家国家透析公司的56个透析设施中担任工作护士角色的199名注册护士。用于设施级分析的样本包括46个透析设施，并且汇总了护士级数据以进行设施级分析。实践环境量表-护理工作指数（PES-NWI）用于衡量护士对透析工作环境的看法。护士离开工作的意图和机构级别的离职率是本研究中检查的护士结局。设施水平的患者满意度和住院率是检查的患者结局。计算相关系数以衡量研究变量之间的关系，并进行独立的t检验以检验工作环境感知中的亚组差异。总体而言，护士对工作环境的评价较高。与打算留下来的护士相比，打算离开工作的护士对工作环境的评价更为负面。在护士对透析工作环境的看法，护士离开工作的意愿，护士离职率和患者住院之间，发现了显着的相关性。研究结果表明，护士对透析工作环境的理解对于透析环境中的护士和患者结局非常重要。需要进一步的研究来探索工作环境对血液透析部门护士和患者结果的预测能力。

BACKGROUND & AIMS: BACKGROUND:Perceived neighborhood characteristics, including satisfaction with one's neighborhood as a place to live, are associated with lower obesity rates and more favorable cardiovascular risk factor profiles. Yet, few studies have evaluated whether changes in perceived neighborhood characteristics over time may be associated with cardiometabolic health indicators. METHODS:Changes in perception of one's neighborhood (2013-2016) were determined from a cohort of residents who lived in one of two low-income urban neighborhoods. Changes were categorized into the following: improvement vs. no change or worsening over the three-year time-period. Multivariable linear regression was used to measure the association between perceived improvement in each of the neighborhood characteristics with cardiometabolic outcomes (BMI, SBP, DBP, HbA1c, HDL-c) that were assessed in 2016, and compared with those who perceived no change or worsening of neighborhood characteristics. Models were adjusted for age, sex, income, education, marital status, physical function, neighborhood, and years spent in neighborhood. To examine potential sex differences, follow-up models were conducted and stratified by sex. RESULTS:Among the 622 individuals who remained in the same neighborhood during the time period, 93% were African American, 80% were female, and the mean age was 58 years. In covariate-adjusted models, those who perceived improvement in their neighborhood safety over the time period had a significantly higher BMI (kg/m2) than those who perceived no improvement or worsening (β = 1.5, p = 0.0162); however, perceived improvement in safety was also significantly associated with lower SBP (mmHg) (β = - 3.8, p = 0.0361). When results were stratified by sex, the relationship between improved perceived neighborhood safety and BMI was only evident in females. CONCLUSIONS:These findings suggest that perceived neighborhood characteristics may impact cardiometabolic outcomes (BMI, SBP), but through differing pathways. This highlights the complexity of the associations between neighborhood characteristics and underscores the need for more longitudinal studies to confirm the associations with cardiometabolic health in African American populations.

背景与目标： 背景：感知到的邻里特征，包括对一个邻里作为居住地的满意度，与较低的肥胖率和更有利的心血管危险因素有关。然而，很少有研究评估随时间变化的感知邻里特征是否可能与心脏代谢健康指标相关。
方法：根据一组居住在两个低收入城市社区之一中的居民来确定自己对邻居的感知变化（2013-2016）。变化可分为以下几类：在三年的时间内，改进与无变化或恶化之间的关系。多变量线性回归用于衡量在2016年评估的每个邻里特征的感知改善与心脏代谢结果（BMI，SBP，DBP，HbA1c，HDL-c）之间的关联，并将其与未发现变化或恶化的患者进行比较邻里特征。模型针对年龄，性别，收入，教育程度，婚姻状况，身体机能，邻里关系以及在邻里生活的时间进行了调整。为了检查潜在的性别差异，进行了随访模型并按性别进行了分层。
结果：在此期间留在同一社区的622个人中，非裔美国人为93％，女性为80％，平均年龄为58岁。在协变量调整模型中，那些在一段时间内感知到邻里安全性改善的人的BMI（kg / m2）明显高于那些没有改善或恶化的人的BMI（βhigher = 1.5，p = 0.0162）；但是，人们认为安全性的改善也与较低的SBP（mmHg）显着相关（β==-3.8，p == 0.0361）。如果按性别对结果进行分层，则仅在女性中，改善的邻里安全感与BMI之间的关系才明显。
结论：这些发现表明，感知的邻里特征可能会影响心脏代谢的结果（BMI，SBP），但会通过不同的途径。这突显了邻里特征之间关联的复杂性，并强调了需要进行更多纵向研究，以确认非裔美国人人群中与心脏代谢健康的关联。

BACKGROUND & AIMS: :The brain is composed of multiple memory systems that mediate distinct types of navigation. The hippocampus is important for encoding and retrieving allocentric spatial cognitive maps, while the dorsal striatum mediates procedural memories based on stimulus-response (S-R) associations. These memory systems are differentially affected by emotional arousal. In particular, rodent studies show that stress typically impairs hippocampal spatial memory while it spares or sometimes enhances striatal S-R memory. The influence of emotional arousal on these separate navigational memory systems has received less attention in human subjects. We investigated the effect of dynamic changes in anticipatory anxiety on hippocampal spatial and dorsal striatal S-R memory systems while participants attempted to solve a virtual eight-arm radial maze. In Experiment 1, participants completed a hippocampus-dependent spatial version of the eight-arm radial maze that required allocentric spatial memory to successfully navigate the environment. In Experiment 2, participants completed a dorsal striatal S-R version of the maze where no allocentric spatial cues were present, requiring the use of S-R navigation. Anticipatory anxiety was modulated via threat of receiving an unpleasant electrical shock to the wrist during memory retrieval. Results showed that threat of shock was associated with more errors and increased use of non-spatial navigational strategies in the hippocampal spatial task, but did not influence memory performance in the striatal S-R task. Findings indicate a dissociation regarding the influence of anticipatory anxiety on memory systems that has implications for understanding how fear and anxiety contribute to memory-related symptoms in human psychopathologies.

背景与目标： ：大脑由多个记忆系统组成，这些记忆系统介导不同类型的导航。海马对编码和检索同心轴空间认知图非常重要，而背侧纹状体则基于刺激-反应（S-R）关联来介导程序记忆。这些记忆系统受情感唤醒的影响不同。特别是，啮齿动物研究表明，压力通常会损害海马的空间记忆，而多余或有时会增强纹状体S-R记忆。情绪唤醒对这些独立的导航记忆系统的影响在人类受试者中受到的关注较少。当参与者试图解决虚拟的八臂radial骨迷宫时，我们调查了预期焦虑的动态变化对海马空间和背侧纹状体S-R记忆系统的影响。在实验1中，参与者完成了八臂放射状迷宫的海马依赖性空间版本，该空间版本需要同心轴空间记忆才能成功地导航环境。在实验2中，参与者完成了迷宫背纹状体S-R版本，其中不存在任何同心轴空间提示，因此需要使用S-R导航。通过记忆检索过程中腕部受到不愉快的电击的威胁，调节了预期的焦虑。结果表明，休克的威胁与更多的错误以及海马空间任务中非空间导航策略的使用增加有关，但并不影响纹状体S-R任务的记忆表现。研究结果表明，预期性焦虑对记忆系统的影响与人格分离，有助于理解恐惧和焦虑如何导致人类心理病理学中与记忆有关的症状。

BACKGROUND & AIMS: :The effects of supplementary ultraviolet-A (UV-A) and ultraviolet-B+A (UV-B+A) in the natural environment on the growth and morphology of various ecotypes of Arabidopsis thaliana were investigated. The ecotypes investigated were Columbia (Col-4), Landsberg erecta (Ler-0), Cvi-0, Wassilewskija, Enkheim-D, Aa-0 and Di-1. The mutant hy-4 was also used. Results varied with the radiation treatment, ecotype and parameter measured. Plants subjected to elevated UV-A were both insensitive (all parameters Cvi-0 and Col-4) and sensitive. When responses to UV-A occurred they were mostly inhibitory (all significant responses of Di-1 and Enkheim-D, most parameters of Wassilewskija, and some parameters of hy-4), however, promotive affects were observed for some parameters of Aa-0 and Ler-0. Supplementary UV-B+A inhibited all parameters of Di-1 and Enkheim-D and most parameters of Col-4, Ler-0 and hy-4, but Wassilewskija, Aa-0 and Cvi-0 were mostly insensitive. The magnitude of the UV-B+A response varied with ecotype (compare Di-1 with Ler-0). Some ecotypes were sensitive to UV-A but not UV-B+A (Aa-0), whereas others (Ler-0, Col-4) show the opposite sensitivities. A linear relationship is reported between the degree of UV-B+A inhibition of each ecotype and growth rate. The higher the growth rate the more susceptible the ecotype is to UV-B+A inhibition. This relationship holds for the majority of growth parameters measured.

背景与目标： ：研究了自然环境中补充紫外线-A（UV-A）和紫外线-BA（UV-BA）对拟南芥各种生态型生长和形态的影响。调查的生态型为哥伦比亚（Col-4），直立兰德斯堡（Ler-0），Cvi-0，Wassilewskija，Enkheim-D，Aa-0和Di-1。还使用了突变体hy-4。结果随辐射处理，生态类型和测得的参数而变化。经受升高的UV-A的植物既不敏感（所有参数Cvi-0和Col-4）又敏感。当发生对UV-A的反应时，它们大部分是抑制性的（Di-1和Enkheim-D的所有显着反应，Wassilewskija的大多数参数以及hy-4的某些参数），但是，对Aa- 0和Ler-0。补充的UV-BA抑制了Di-1和Enkheim-D的所有参数以及Col-4，Ler-0和hy-4的大多数参数，但是Wassilewskija，Aa-0和Cvi-0大多不敏感。 UV-BA反应的强度随生态型而变化（将Di-1与Ler-0进行比较）。一些生态型对UV-A敏感，但对UV-BA不敏感（Aa-0），而其他生态型（Ler-0，Col-4）显示出相反的敏感性。据报道，每种生态型对UV-BA的抑制程度与生长速率之间存在线性关系。生长速率越高，生态型就更容易受到UV-BA的抑制。这种关系适用于大多数测得的生长参数。

BACKGROUND & AIMS: :Salinity is one of the most important abiotic factors in various natural habitats of microbes. Cyanobacteria are the most widely distributed family of photosynthetic microorganisms in environments with fluctuating salinity. In response to salt stress, many cyanobacteria de novo synthesize compatible solutes to maintain osmotic balance in the cell. However, the regulation of intracellular accumulation of these compounds is still not well understood. The freshwater cyanobacterium Synechococcus elongatus PCC 7942 (Syn7942) exclusively accumulates sucrose as a compatible solute upon salt stress and is thus an ideal model microorganism for studying the metabolism of compatible solute dynamics. Here, we focused on elucidating the regulatory mechanisms involved in salt-induced sucrose accumulation in Syn7942. Using a series of physiological and biochemical experiments, we showed that the ionic effect of salt stress plays an important role in inducing sucrose synthesis, whereby elevated ion concentration directly activates the sucrose-synthesizing enzyme sucrose-phosphate synthase and simultaneously inhibits the sucrose-degrading enzyme invertase, resulting in a rapid sucrose accumulation. Thus, we propose a novel mechanism for cyanobacterial adaption to salt stress and fluctuating salinity, i.e., the ion-induced synergistic modulation of the enzymes synthesizing and degrading compatible solutes. These findings greatly enhance our current understanding of microbial adaptation to salt.IMPORTANCE Most microbes de novo synthesize compatible solutes for adaptation to salt stress or fluctuating salinity environments. However, to date, one of the core questions involved in these physiological processes, i.e., the regulation of salt-induced compatible solute biosynthesis, is still not well understood. Here, this issue was systematically investigated by employing the model freshwater cyanobacterium Synechococcus elongatus PCC 7942. A novel mechanism for cyanobacterial adaption to salt stress and fluctuating salinity, i.e., the ion-induced synergistic modulation of key synthesizing and degrading enzymes of compatible solutes, is proposed. Because the ion-induced activation/inhibition of enzymes is a fast and efficient process, it may represent a common strategy of microbes for adaptation to environments with fluctuating salinity.

背景与目标： 盐度是微生物各种自然生境中最重要的非生物因素之一。蓝细菌是盐度波动的环境中分布最广泛的光合微生物家族。响应盐胁迫，许多从头开始的蓝细菌可以合成兼容的溶质，以维持细胞内的渗透平衡。然而，对这些化合物的细胞内积累的调节仍不十分了解。淡水蓝藻延长线蓝藻PCC 7942（Syn7942）在盐胁迫下专门积累蔗糖作为相容性溶质，因此是研究相容性溶质动力学代谢的理想模型微生物。在这里，我们集中于阐明参与盐诱导的Syn7942中蔗糖积累的调控机制。通过一系列生理和生化实验，我们表明盐胁迫的离子效应在诱导蔗糖合成中起着重要作用，其中升高的离子浓度直接激活了蔗糖合成酶蔗糖磷酸合成酶，同时抑制了蔗糖降解酶。蔗糖转化酶，导致蔗糖迅速积累。因此，我们提出了一种蓝藻适应盐胁迫和波动盐度的新机制，即离子诱导的酶的协同调节，以合成和降解相容的溶质。这些发现极大地增强了我们目前对微生物对盐的适应性的认识。重要提示从头开始，大多数微生物会合成兼容的溶质，以适应盐胁迫或盐度波动的环境。然而，迄今为止，仍未很好地理解这些生理过程涉及的核心问题之一，即盐诱导的相容性溶质生物合成的调节。在这里，我们通过使用模型淡水蓝藻延长线PCC 7942对这一问题进行了系统地研究。一种新的蓝藻适应盐胁迫和波动盐度的机制，即离子诱导的关键性合成和降解兼容溶质酶的协同调节。建议的。因为离子诱导的酶的激活/抑制是一个快速而有效的过程，所以它可能代表了微生物适应盐度波动环境的常见策略。

BACKGROUND & AIMS: :In today's continually changing health care environment, there is serious concern that medical students are not being adequately prepared to provide optimal health care in the system where they will eventually practice. To address this problem, the Health Resources and Services Administration (HRSA) developed a $7.6 million national demonstration project, Undergraduate Medical Education for the 21st Century (UME-21). This project funded 18 U.S. medical schools, both public and private, for a three-year period (1998-2001) to implement innovative educational strategies. To accomplish their goals, the 18 UME-21 schools worked with more than 50 organizations external to the medical school (e.g., managed care organizations, integrated health systems, Area Health Education Centers, community health centers). The authors describe the major curricular changes that have been implemented through the UME-21 project, discuss the challenges that occurred in carrying out those changes, and outline the strategies for evaluating the project. The participating schools have developed curricular changes that focus on the core primary care clinical clerkships, take place in ambulatory settings, include learning objectives and competencies identified as important to providing care in the future health care system, and have faculty development and internal evaluation components. Curricular changes implemented at the 18 schools include having students work directly with managed care organizations, as well as special demonstration projects to teach students the knowledge, skills, and attitudes necessary for successfully managing care. It is already clear that the UME-21 project has catalyzed important curricular changes within 12.5% of U.S. medical schools. The ongoing national evaluation of this project, which will be completed in 2002, will provide further information about the project's impact and effectiveness.

背景与目标： ：在当今不断变化的医疗保健环境中，人们非常担心医学生没有充分准备好在他们最终将要练习的系统中提供最佳医疗保健。为了解决这个问题，美国卫生资源与服务管理局（HRSA）制定了一项耗资760万美元的国家示范项目，即面向21世纪的本科医学教育（UME-21）。该项目在三年期间（1998-2001年）为18所美国公立和私立医学院校提供了资金，以实施创新的教育策略。为了实现其目标，这18所UME-21学校与医学院校外部的50多个组织（例如，管理式护理组织，综合卫生系统，区域健康教育中心，社区卫生中心）合作。作者描述了通过UME-21项目实施的主要课程变更，讨论了进行这些变更时遇到的挑战，并概述了评估项目的策略。参与的学校已经制定了课程改革，重点是在门诊环境中进行的核心初级保健临床业务，包括被认为对将来的医疗体系提供医疗服务至关重要的学习目标和能力，并且具有教师发展和内部评估的组成部分。在这18所学校中实施的课程改革包括让学生直接与托管式护理组织合作，以及特殊的示范项目，以向学生传授成功管理护理所必需的知识，技能和态度。已经很明显，UME-21项目在美国医学院的12.5％范围内催化了重要的课程变化。正在进行的国家对该项目的评估将在2002年完成，它将提供有关该项目的影响和效力的进一步信息。

BACKGROUND & AIMS: BACKGROUND:Students' perceptions of their academic learning environment have been found to be related to their approaches to learning and learning outcomes. Educational environment is just beginning to be researched in nursing education with the vast majority of studies focusing on the clinical educational environment. Accelerated Bachelor of Science in Nursing (ABSN) programs for students who have obtained a bachelor degree are a popular nursing pedagogue. These programs are instituted on the belief that degreed students have the ability to be successful in a demanding program, are older, are adult learners and tend to be more motivated than their traditional counterparts. There is a paucity of research exploring the differences in student perceptions of the educational environment between the traditional and accelerated programs. OBJECTIVE:Explore students' perceptions of the educational environment in the traditional and ABSN programs within an institution and determine any differences. DESIGN:Comparative descriptive study. SETTING:Private school of Nursing in the Southwest. PARTICIPANTS:Convenience sample of 24 ABSN and 38 traditional graduating senior students. METHODS:Invited students completed the Dundee Ready Education Environment Measure through the online survey application Qualtrics. An independent t-test was used to compare the scores. RESULTS:A total of 62 students completed the survey for an overall response rate of 57%. No statistical difference was found in students' perceptions of academic environment between the two groups on the total score. However, there was a statistically significant difference on the sub-domain pertaining to atmosphere and there were significant differences on 6 out of 50 individual items. CONCLUSIONS:The results of this study indicate that, taken in its entirety, there was no significant difference in student perception of educational environment between the traditional and accelerated cohorts at this institution as measured by the DREEM tool. However, there was a significant difference between the two cohorts within the student perception of Atmosphere sub-domain and on seven individual items. The DREEM tool was found to be a reliable instrument to determine students' perceptions of educational environment.

背景与目标： 背景：已经发现学生对其学术学习环境的看法与其学习方法和学习成果有关。在护理教育中，教育环境的研究才刚刚开始，绝大多数研究都集中在临床教育环境上。面向获得学士学位的学生的加速护理学学士（ABSN）计划是一种流行的护理教育家。这些课程的建立是基于以下信念：有学位的学生有能力在要求苛刻的课程中取得成功，年龄更大，是成年学习者，并且比传统的学习者更有动力。很少有研究探讨传统课程和加速课程之间学生对教育环境的看法的差异。
目的：在机构内的传统课程和ABSN课程中探索学生对教育环境的看法，并确定是否存在差异。
设计：比较描述性研究。
地点：西南私立护理学校。
参与者：24名ABSN和38名传统即将毕业的高年级学生的便利样本。
方法：受邀学生通过在线调查应用Qualtrics完成了Dundee准备教育环境评估。使用独立的t检验比较得分。
结果：共有62名学生完成了调查，总体答复率为57％。两组之间在学生对学术环境的看法上没有发现统计学差异。但是，与大气有关的子域在统计上存在显着差异，并且在50个单独项目中有6个存在显着差异。
结论：这项研究的结果表明，从整体上看，通过DREEM工具测量，该机构的传统人群和加速人群在教育环境方面的学生认知没有显着差异。但是，在学生对“大气”子域的理解以及在七个单独项目上，这两个队列之间存在显着差异。发现DREEM工具是确定学生对教育环境的看法的可靠工具。

BACKGROUND & AIMS: OBJECTIVE:Intraoperative MRI is considered the gold standard among all intraoperative imaging technologies currently available. Its main indication is in the intraoperative detection of residual disease during tumour resections. We present our initial experience with the first intraoperative low-field MRI in a Spanish hospital of the public healthcare system. We evaluate its usefulness and accuracy to detect residual tumours and compare its intraoperative results with images obtained postoperatively using conventional high-field devices. MATERIAL AND METHODS:We retrospectively reviewed the first 21 patients operated on the aid of this technology. Maximal safe resection was the surgical goal in all cases. Surgeries were performed using conventional instrumentation and the required assistance in each case. RESULTS:The mean number of intraoperative studies was 2.3 per procedure (range: 2 to 4). Intraoperative studies proved that the surgical goal had been achieved in 15 patients (71.4%), and detected residual tumour in 6 cases (28.5%). After comparing the last intraoperative image and the postoperative study, 2 cases (9.5%) were considered as "false negatives". CONCLUSIONS:Intraoperative MRI is a safe, reliable and useful tool for guided resection of brain tumours. Low-field devices provide images of sufficient quality at a lower cost; therefore their universalisation seems feasible.

背景与目标： 目的：术中MRI被认为是目前所有术中成像技术中的黄金标准。它的主要指征是在肿瘤切除术中对残留疾病的术中检测。我们介绍了我们在西班牙第一家公共医疗系统医院进行的术中低场MRI的初步经验。我们评估其有效性和准确性，以检测残留的肿瘤，并将其术中结果与术后使用常规高场设备获得的图像进行比较。
材料与方法：我们回顾性地回顾了首例采用该技术手术的21例患者。在所有情况下，最大的安全切除是手术的目标。手术均使用常规仪器进行，并在每种情况下均需要所需的协助。
结果：术中平均研究次数为每项手术2.3次（范围：2到4）。术中研究证明，有15例患者（71.4％）达到了手术目标，有6例（28.5％）检出了残留肿瘤。比较最后的术中影像和术后研究后，有2例（9.5％）被认为是“假阴性”。
结论：术中MRI是一种安全，可靠和有用的工具，可用于脑肿瘤的指导性切除。低场设备以较低的成本提供了足够质量的图像；因此，将它们普遍化似乎是可行的。