• 【圆柱和圆锥形谐振器中的高振幅非线性声波驱动的流场。】 复制标题 收藏 收藏
    DOI:10.1121/1.4807635 复制DOI
    作者列表:Antao DS,Farouk B
    BACKGROUND & AIMS: :A high fidelity computational fluid dynamic model is used to simulate the flow, pressure, and density fields generated in a cylindrical and a conical resonator by a vibrating end wall/piston producing high-amplitude standing waves. The waves in the conical resonator are found to be shock-less and can generate peak acoustic overpressures that exceed the initial undisturbed pressure by two to three times. A cylindrical (consonant) acoustic resonator has limitations to the output response observed at one end when the opposite end is acoustically excited. In the conical geometry (dissonant acoustic resonator) the linear acoustic input is converted to high energy un-shocked nonlinear acoustic output. The model is validated using past numerical results of standing waves in cylindrical resonators. The nonlinear nature of the harmonic response in the conical resonator system is further investigated for two different working fluids (carbon dioxide and argon) operating at various values of piston amplitude. The high amplitude nonlinear oscillations observed in the conical resonator can potentially enhance the performance of pulse tube thermoacoustic refrigerators and these conical resonators can be used as efficient mixers.
    背景与目标: :高保真计算流体动力学模型用于模拟由振动端壁/活塞产生高振幅驻波而在圆柱和圆锥形谐振器中产生的流场,压力和密度场。发现圆锥形谐振器中的波无冲击,并且可以产生峰值声学超压,其超过初始未扰动压力的2到3倍。当在另一端被声学激励时,圆柱形(辅音)声谐振器对在一端观察到的输出响应具有局限性。在圆锥形几何体(谐振声学谐振器)中,线性声学输入被转换为高能量,不受电击的非线性声学输出。使用过去在圆柱谐振器中驻波的数值结果验证了该模型。对于在活塞振幅的各种值下工作的两种不同的工作流体(二氧化碳和氩气),将进一步研究圆锥形谐振器系统中谐波响应的非线性特性。在圆锥形谐振器中观察到的高振幅非线性振荡可以潜在地增强脉冲管热声制冷机的性能,并且这些圆锥形谐振器可以用作有效的混频器。
  • 【麻醉领域的活跃研究领域:麻醉文献的文献共引分析。】 复制标题 收藏 收藏
    DOI:10.1213/ane.0b013e31816d18a1 复制DOI
    作者列表:Jankovic MP,Kaufmann M,Kindler CH
    BACKGROUND & AIMS: BACKGROUND:The expansion of science has resulted in an increased information flow and in an exponentially growing number of connections between knowledge in different research fields. In this study, we used methods of scientometric analysis to obtain a conceptual network that forms the structure of active scientific research fields in anesthesia. METHODS:We extracted from the Web of Science (Institute for Scientific Information) all original articles (n = 3275) including their references (n = 79,972) that appeared in 2003 in all 23 journals listed in the Institute for Scientific Information Journal Citation Reports under the subject heading "Anesthesiology." After identification of highly cited references (> or = 5), pairs of co-cited references were created and grouped into uniformly structured clusters of documents using a single linkage and variable level clustering method. In addition, for each such cluster of documents, we identified corresponding front papers published in 2003, each of which co-cited at least two documents of the cluster core. Active anesthetic research fields were then named by examining the titles of the documents in both the established clusters and in their corresponding front papers. These research fields were sorted according to the proportion of recent documents in their cluster core (immediacy index) and were further analyzed. RESULTS:Forty-six current anesthetic research fields were identified. The research field named "ProSeal laryngeal mask airway" showed the highest immediacy index (100%) whereas the research fields "Experimental models of neuropathic pain" and "Volatile anesthetic-induced cardioprotection" exhibited the highest level of co-citation strength (level 9). The research field with the largest cluster core, containing 12 homogeneous papers, was "Postoperative nausea and vomiting." The journal Anesthesia & Analgesia published most front papers while Anesthesiology published most of the fundamental documents used as references in the front papers. CONCLUSIONS:Using co-citation analysis, we identified distinct homogenous clusters of highly cited documents representing 46 active current anesthetic research fields and determined multiple nets of knowledge among them.
    背景与目标: 背景:科学的发展导致信息流增加,不同研究领域的知识之间的联系呈指数增长。在这项研究中,我们使用了科学计量分析的方法来获得一个概念网络,该网络形成了麻醉领域活跃的科研领域的结构。
    方法:我们从Web of Science(科学信息研究所)中提取了所有原始文章(n = 3275),包括其参考文献(n = 79,972),这些文章出现在2003年在《科学信息研究所期刊引文报告》下列出的所有23种期刊中主题为“麻醉学”。在识别出高引用的参考文献(>或= 5)之后,使用单链接和可变级别聚类方法创建成对的同被引用参考文献,并将其分组为结构统一的文档簇。另外,对于每个这样的文档集群,我们确定了2003年发布的相应的前文,其中每篇都共同引用了该集群核心的至少两个文档。然后,通过检查已建立的集群及其相应的前文中文件的标题来命名活跃的麻醉研究领域。这些研究领域根据其集群核心中的最新文献的比例(即时指数)进行分类,并进行了进一步分析。
    结果:目前已确定了46种麻醉药研究领域。名为“ ProSeal喉罩气道”的研究领域具有最高的即时指数(100%),而“神经病理性疼痛的实验模型”和“挥发性麻醉药诱导的心脏保护”研究领域表现出最高的共被引强度(9级) )。簇状核最大的研究领域是“术后恶心和呕吐”,其中包含12篇同类论文。 《麻醉与镇痛》杂志发表了大多数前期论文,而《麻醉学》则发表了用作前篇论文参考的大多数基本文献。
    结论:使用共引分析法,我们鉴定了代表46个活跃的当前麻醉研究领域的,被高度引用的文献的不同同质簇,并在其中确定了多个知识网络。
  • 【使用随机血与单采血血小板浓缩液。】 复制标题 收藏 收藏
    DOI:10.1016/j.tracli.2008.01.004 复制DOI
    作者列表:Andreu G,Vasse J,Sandid I,Tardivel R,Semana G
    BACKGROUND & AIMS: :The respective use of random (RPC) and apheresis (APC) platelet concentrates is highly heterogeneous among countries, ranging from 10 to 98% RPC in countries supposed to provide a similar transfusion service to patients. Moreover, when considering each country in the past 10 years, one can observe that some have changed their policy, switching from a majority of APC to RPC or vice versa. This presentation intends to analyse which factors may impact such decisions. For many years, the only available platelet component was a RPC obtained from whole blood donation by a two centrifugation steps process, the "platelet rich plasma" or PRP method. Since the beginning of the 1970s, APCs became available, with in fact many different techniques leading to many APCs that may not be equivalent. Since the end of the 1980s, a new method of RPC preparation was developed, using the buffy-coat (BC-PC), providing a blood component with highly preserved platelet functions as compared to RPCs prepared by the PRP technique. Finally, the use of each of these components either native, or leuco-reduced, or suspended in a storage solution, or processed with a pathogen inactivation technique adds new layers of complexity to compare them. Innumerable references can be found in the literature describing in vitro functional parameters of platelet concentrates. Although it is clear that BC-RPC retain much more their in vitro functions than PRP-RPC, indicating that no one should use the latter any more, it is much more difficult to distinguish differences between other PCs. Conversely, only a very few studies have been published related to a comparison of clinical efficacy of RPC versus APC, the endpoints being mainly CCI. Similarly to the in vitro studies, although RPC prepared with the PRP method show the lowest CCIs, no clear difference exists between "modern" RPC and APC. Another factor that may impact policy decision is the occurrence of adverse reactions in recipients. When considering only comparable data, for example leuco-reduced RPC versus leuco-reduced APC, there is now evidence that the latter is more associated with adverse reactions in recipients: data from hemovigilance in France show that, although no difference is noted for febrile non haemolytic transfusion reactions, nor for bacteria contamination, the incidence of allergic adverse reactions is about four times higher with APC as compared with RPC. Other aspects may impact the decision: the fact that using APC in place of RPC reduces the total donor exposure of patients was considered critical in some countries to reduce the risk of transmission of blood transmissible disease. Finally, the cost of the components, much higher for APC may be considered.
    背景与目标: :随机(RPC)和单采血液(APC)血小板浓缩液的使用在各国之间是高度异质的,在应该向患者提供类似输血服务的国家中,RPC的使用范围从10%到98%不等。此外,在过去10年中考虑每个国家时,可以观察到一些国家改变了其政策,从大多数APC转换为RPC,反之亦然。本演示文稿旨在分析哪些因素可能影响此类决策。多年来,唯一可用的血小板成分是通过两个离心步骤过程(“富含血小板的血浆”或PRP方法)从全血中获得的RPC。自1970年代初以来,APC便已问世,实际上有许多不同的技术导致许多APC可能不等效。自1980年代末以来,使用血沉棕黄层(BC-PC)开发了一种新的RPC制备方法,与通过PRP技术制备的RPC相比,该血液组分具有高度保留的血小板功能。最后,使用这些天然成分或无色成分减少的成分,或悬浮在存储溶液中或使用病原体灭活技术处理的成分,都增加了新的复杂度来比较它们。在描述血小板浓缩物的体外功能参数的文献中可以找到无数的参考文献。尽管很明显BC-RPC比PRP-RPC保留了更多的体外功能,这表明没有人可以再使用PRP-RPC,但是要区分其他PC之间的差异要困难得多。相反,只有很少的研究发表过与RPC和APC的临床疗效比较相关的研究,其终点主要是CCI。与体外研究相似,尽管用PRP方法制备的RPC显示出最低的CCI,但“现代” RPC和APC之间没有明显的区别。可能影响政策决策的另一个因素是受助者中发生的不良反应。当仅考虑可比较的数据时,例如白细胞减少的RPC与白细胞减少的APC,现在有证据表明后者与接受者的不良反应相关:法国的血液警惕性数据表明,尽管对于发热性非酒精性脂肪性肝炎没有观察到差异。与RPC相比,APC的溶血性输血反应或细菌污染的变态反应性不良反应的发生率大约高四倍。其他方面可能会影响该决策:在某些国家,使用APC代替RPC可以减少患者的总供体暴露这一事实对于减少血液传播疾病的传播风险至关重要。最后,可以考虑组件的成本,对于APC而言,成本要高得多。
  • 【单次和随机供血者血小板供血5天储存期间的血小板功能测试。】 复制标题 收藏 收藏
    DOI:10.1016/j.transci.2007.03.008 复制DOI
    作者列表:Akay OM,Gündüz E,Başyiğit H,Gulbas Z
    BACKGROUND & AIMS: :Platelet concentrates are routinely manufactured from whole blood by differential centrifugation (random donor platelets-RDP) or by plateletpheresis (single donor platelets-SDP). These platelet concentrates have a storage period of 5 days and many different approaches exist to measure the condition of platelets during their storage. In this study, platelet aggregation testing using adenosine diphosphate (ADP) and collagen and flow cytometric platelet activation analysis using CD41 FITC and CD62 PE before and after ADP was performed on days 1, 3 and 5 of storage of platelet preparations. Thirty three RDPs, stored in Baxter and Kansuk blood bags and 18 SDPs stored in Fresenius blood bags were evaluated. In RDPs and in SDPs; ADP and collagen induced PA responses were decreased significantly on the 3rd and 5th days compared to 1st day. CD62 positive platelet percentage after ADP were decreased significantly on the 3rd and 5th days compared to the 1st day in Kansuk bags. Flow cytometric analysis revealed minor changes in CD41 expression after ADP on the 3rd day compared to 1st day and on the 5th day compared to 3rd day. Differences in CD62 positive platelet percentage were not significant between the RDPs and SDPs. Our results suggest that: (1) ADP and collagen induced PA responses decrease both in RDPs and SDPs during storage. (2) Flow cytometric analysis does not show major significant changes in platelet activation after ADP during storage. (3) Continous shaking on the agitator does not cause a significant change in CD62 positive platelet percentage during storage. (4) Platelet aggregation responses in RDPs stored in Baxter and Kansuk blood bags do not differ during storage.
    背景与目标: 血小板浓缩物通常通过全血通过差速离心(随机供体血小板-RDP)或血小板分离(单供体血小板-SDP)制成。这些血小板浓缩物的储存期为5天,并且存在许多不同的方法来测量血小板在储存过程中的状况。在这项研究中,在血小板制品储存的第1、3和5天进行了使用二磷酸腺苷(ADP)和胶原蛋白进行的血小板聚集测试,以及在使用ADP之前和之后使用CD41 FITC和CD62 PE进行的流式细胞术血小板活化分析。对存储在Baxter和Kansuk血袋中的33个RDP和存储在费森尤斯血袋中的18个SDP进行了评估。在RDP和SDP中;与第一天相比,第三天和第五天ADP和胶原蛋白诱导的PA反应显着降低。与Kansuk袋中的第1天相比,ADP后第3天和第5天的CD62阳性血小板百分比显着下降。流式细胞仪分析显示,与第一天相比,ADP后第3天和第3天与第5天相比,CD41的表达有轻微变化。 RDP和SDP之间CD62阳性血小板百分比的差异不显着。我们的结果表明:(1)在储存过程中,ADP和胶原诱导的PA反应在RDP和SDP中均降低。 (2)流式细胞仪分析未显示ADP储存后血小板活化的主要显着变化。 (3)在储存过程中,在搅拌器上连续摇动不会引起CD62阳性血小板百分比的显着变化。 (4)储存在Baxter和Kansuk血袋中的RDP中的血小板聚集反应没有差异。
  • 【酪氨酸欧文氏菌tyrR基因的克隆和随机诱变,用于酪氨酸酚裂解酶的高水平表达。】 复制标题 收藏 收藏
    DOI:10.1128/aem.66.11.4764-4771.2000 复制DOI
    作者列表:Katayama T,Suzuki H,Koyanagi T,Kumagai H
    BACKGROUND & AIMS: :Tyrosine phenol-lyase (Tpl), which can synthesize 3, 4-dihydroxyphenylalanine from pyruvate, ammonia, and catechol, is a tyrosine-inducible enzyme. Previous studies demonstrated that the tpl promoter of Erwinia herbicola is activated by the TyrR protein of Escherichia coli. In an attempt to create a high-Tpl-expressing strain, we cloned the tyrR gene of E. herbicola and then randomly mutagenized it. Mutant TyrR proteins with enhanced ability to activate tpl were screened for by use of the lac reporter system in E. coli. The most increased transcription of tpl was observed for the strain with the mutant tyrR allele involving amino acid substitutions of alanine, cysteine, and glycine for valine-67, tyrosine-72, and glutamate-201, respectively. A tyrR-deficient derivative of E. herbicola was constructed and transformed with a plasmid carrying the mutant tyrR allele (V67A Y72C E201G substitutions). The resultant strain expressed Tpl without the addition of tyrosine to the medium and produced as much of it as was produced by the wild-type strain grown under tyrosine-induced conditions. The regulatory properties of the mutant TyrR(V67A), TyrR(Y72C), TyrR(E201G), and TyrR(V67A Y72C E201G) proteins were examined in vivo. Interestingly, as opposed to the wild-type TyrR protein, the mutant TyrR(V67A) protein had a repressive effect on the tyrP promoter in the presence of phenylalanine as the coeffector.
    背景与目标: 酪氨酸酚裂解酶(Tpl)可以从酪氨酸,氨水和邻苯二酚合成3,4-二羟基苯丙氨酸,是一种酪氨酸诱导酶。先前的研究表明,草食欧文氏菌的tpl启动子被大肠杆菌的TyrR蛋白激活。为了创建高表达Tpl的菌株,我们克隆了E. herbicola的tyrR基因,然后对其进行了随机诱变。通过使用大肠杆菌中的lac报告系统筛选具有增强的tpl激活能力的突变TyrR蛋白。对于具有突变tyrR等位基因的菌株,观察到tpl的转录增加最多,所述突变体分别涉及丙氨酸,半胱氨酸和甘氨酸的氨基酸取代缬氨酸67,酪氨酸72和谷氨酸201。构建了E. herbicola的tyrR缺陷型衍生物,并用携带突变型tyrR等位基因(V67A Y72C E201G替代)的质粒转化。所得菌株在不向培养基中添加酪氨酸的情况下表达Tpl,并产生与在酪氨酸诱导的条件下生长的野生型菌株所产生的一样多的菌株。在体内检查了突变体TyrR(V67A),TyrR(Y72C),TyrR(E201G)和TyrR(V67A Y72C E201G)蛋白的调控特性。有趣的是,与野生型TyrR蛋白相反,突变型TyrR(V67A)蛋白在存在苯丙氨酸作为协同增效剂的情况下对tyrP启动子具有抑制作用。
  • 【通过对运动调制和不进行动态多叶准直仪跟踪而进行的体积调制电弧治疗场的运动编码来进行时间分辨剂量重建。】 复制标题 收藏 收藏
    DOI:10.3109/0284186X.2013.818248 复制DOI
    作者列表:Ravkilde T,Keall PJ,Grau C,Høyer M,Poulsen PR
    BACKGROUND & AIMS: BACKGROUND:Organ motion during treatment delivery in radiotherapy (RT) may lead to deterioration of the planned dose, but can be mitigated by dynamic multi-leaf collimator (DMLC) tracking. The purpose of this study was to implement and experimentally validate a method for time-resolved motion including dose reconstruction for volumetric modulated arc therapy (VMAT) treatments delivered with and without DMLC tracking. MATERIAL AND METHODS:Tracking experiments were carried out on a linear accelerator (Trilogy, Varian) with a prototype DMLC tracking system. A motion stage carrying a biplanar dosimeter phantom (Delta4PT, Scandidos) reproduced eight representative clinical tumor trajectories (four lung, four prostate). For each trajectory, two single-arc 6 MV VMAT treatments with low and high modulation were delivered to the moving phantom with and without DMLC tracking. An existing in-house developed program that adds target motion to treatment plans was extended with the ability to split an arc plan into any number of sub-arcs, allowing the calculated dose for different parts of the treatment to be examined individually. For each VMAT sub-arc, reconstructed and measured doses were compared using dose differences and 3%/3 mm γ-tests. RESULTS:For VMAT sub-arcs the reconstructed dose distributions had a mean root-mean-square (rms) dose difference of 2.1% and mean γ failure rate of 2.0% when compared with the measured doses. For final accumulated doses the mean rms dose difference was 1.6% and the γ failure rate was 0.7%. CONCLUSION:The time-resolved motion including dose reconstruction was experimentally validated for complex tracking and non-tracking treatments with patient-measured tumor motion trajectories. The reconstructed dose will be of high value for evaluation of treatment plan robustness facing organ motion and adaptive RT.
    背景与目标: 背景:放射治疗(RT)进行治疗期间的器官运动可能会导致计划剂量的恶化,但可以通过动态多叶准直仪(DMLC)跟踪来缓解。这项研究的目的是实施并通过实验验证一种用于时间分辨运动的方法,包括采用和不采用DMLC跟踪进行体积调制电弧治疗(VMAT)治疗的剂量重建。
    材料与方法:跟踪实验是在具有原型DMLC跟踪系统的线性加速器(Trilogy,Varian)上进行的。携带双平面剂量计体模(Delta4PT,Scandidos)的运动台可再现八种代表性的临床肿瘤轨迹(四肺,四前列腺)。对于每个轨迹,在有和没有DMLC跟踪的情况下,将具有低调制和高调制的两种单弧6 MV VMAT处理传递给运动体模。现有的内部开发程序可以将目标运动添加到治疗计划中,并且可以将电弧计划划分为任意数量的子弧线,从而可以单独检查治疗不同部分的计算出的剂量,从而扩展了功能。对于每个VMAT子电弧,使用剂量差异和3%/ 3 mmγ测试比较重建和测量的剂量。
    结果:对于VMAT亚弧,与测量剂量相比,重建的剂量分布的平均均方根(rms)剂量差异为2.1%,平均γ失效率为2.0%。对于最终累积剂量,平均均方根剂量差异为1.6%,γ失效率为0.7%。
    结论:包括剂量重建在内的时间分辨运动已通过实验验证,可用于采用患者测量的肿瘤运动轨迹进行复杂的跟踪和非跟踪治疗。重建的剂量对于评估面向器官运动和适应性RT的治疗计划的鲁棒性将具有很高的价值。
  • 【长期暴露于0.5 T静磁场对GH3细胞生长和大小的影响。】 复制标题 收藏 收藏
    DOI:10.1002/bem.20452 复制DOI
    作者列表:Rosen AD,Chastney EE
    BACKGROUND & AIMS: :Brief exposure to moderate intensity static magnetic fields has been shown to produce a transient alteration in physiological function in a variety of biological systems, primarily those related to changes in intracellular Ca(2+). In the present study GH3 cells were cultured during continuous exposure to a 0.5 T field, for periods of up to 5 weeks. Following a 1-week exposure, cell growth declined by 22% and returned to control levels in 1 week. This was not statistically significant but, with a 4-week exposure, a statistically significant decline in growth of 51% was observed and return to control levels did not occur for 4 weeks. Cell diameter, on the other hand, significantly increased following 3 weeks of exposure and did not return to control levels for 3 weeks after termination of exposure. Ca(2+)-dependent changes in the dynamic reorganization of the actin cytoskeleton are suggested as the probable explanation for these observations.
    背景与目标: :短暂暴露于中等强度的静磁场已显示在多种生物系统中,主要是与细胞内Ca(2)的变化有关的生理功能中,产生暂时性的生理变化。在本研究中,在连续暴露于0.5 T场的过程中培养GH3细胞长达5周。暴露1周后,细胞生长下降了22%,并在1周内恢复到对照水平。这在统计学上不显着,但是在暴露4周后,观察到生长增长在统计学上显着下降51%,并且在4周内未出现恢复到对照水平的情况。另一方面,细胞直径在接触3周后显着增加,并且在接触终止后3周未恢复到对照水平。 Ca(2)依赖变化的肌动蛋白细胞骨架的动态重组被建议为这些观察结果的解释。
  • 【使用非均匀马尔可夫链和神经网络预测灵长类动物的剪接位点。】 复制标题 收藏 收藏
    DOI:10.1089/dna.2007.0583 复制DOI
    作者列表:Liu L,Ho YK,Yau S
    BACKGROUND & AIMS: :The inhomogeneous Markov chain model is used to discriminate acceptor and donor sites in genomic DNA sequences. It outperforms statistical methods such as homogeneous Markov chain model, higher order Markov chain and interpolated Markov chain models, and machine-learning methods such as k-nearest neighbor and support vector machine as well. Besides its high accuracy, another advantage of inhomogeneous Markov chain model is its simplicity in computation. In the three states system (acceptor, donor, and neither), the inhomogeneous Markov chain model is combined with a three-layer feed forward neural network. Using this combined system 3175 primate splice-junction gene sequences have been tested, with a prediction accuracy of greater than 98%.
    背景与目标: :非均匀马尔可夫链模型用于区分基因组DNA序列中的受体和供体位点。它优于统计方法,例如齐次马尔可夫链模型,高阶马尔可夫链和插值马尔可夫链模型,以及k-最近邻和支持向量机等机器学习方法。非均质马尔可夫链模型除了具有很高的准确性外,它的另一个优点是计算简单。在三态系统(受体,供体和两者都不是)中,不均匀的马尔可夫链模型与三层前馈神经网络结合在一起。使用该组合系统,已经测试了3175个灵长类动物剪接连接基因序列,其预测精度大于98%。
  • 【暴露于随机定位机的人多药耐药性Jurkat / A4细胞的细胞间粘附分子3表面表达的变化,凋亡的诱导和细胞周期进程的抑制。】 复制标题 收藏 收藏
    DOI:10.3390/ijms21030855 复制DOI
    作者列表:Sokolovskaya A,Korneeva E,Zaichenko D,Virus E,Kolesov D,Moskovtsev A,Kubatiev A
    BACKGROUND & AIMS: :Experiments from flight- and ground-based model systems suggest that unexpected alterations of the human lymphoblastoid cell line Jurkat, as well as effects on cell growth, metabolism, and apoptosis, can occur in altered gravity conditions. Using a desktop random positioning machine (RPM), we investigated the effects of simulated microgravity on Jurkat cells and their multidrug-resistant subline, Jurkat/A4 cells. The viability of Jurkat/A4 cells decreased after simulated microgravity in contrast with the Jurkat cells. At the same time, the viability between the experimental Jurkat cells and control Jurkat cells was not significantly different. Of note, Jurkat cells appeared as less susceptible to apoptosis than their multidrug-resistant clone Jurkat/A4 cells, whereas cell-cycle analysis showed that the percentage of Jurkat/A4 cells in the S-phase was increased after 72 and 96 h of RPM-simulated microgravity relative to their static counterparts. The differences in Jurkat cells at all phases between static and simulated microgravity were not significant. The surface expression of the intercellular adhesion molecule 3 (ICAM-3)-also known as cluster of differentiation (CD)50-protein was changed for Jurkat/A4 cells following exposure to the RPM. Changes in cell morphology were observed in the Jurkat/A4 cells after 96 h of RPM-simulated microgravity. Thus, we concluded that Jurkat/A4 cells are more sensitive to RPM-simulated microgravity as compared with the parental Jurkat cell line. We also suggest that intercellular adhesion molecule 3 may be an important adhesion molecule involved in the induction of leukocyte apoptosis. The Jurkat/A4 cells with an acquired multidrug resistance phenotype could be a useful model for studying the effects of simulated microgravity and testing anticancer drugs.
    背景与目标: :基于飞行和地面的模型系统的实验表明,人的淋巴母细胞样细胞系Jurkat发生意想不到的改变,以及对细胞生长,代谢和细胞凋亡的影响,都可能在重力条件改变的情况下发生。我们使用台式随机定位机(RPM),研究了模拟微重力对Jurkat细胞及其耐多药亚系Jurkat / A4细胞的影响。与Jurkat细胞相比,模拟微重力作用后Jurkat / A4细胞的活力降低。同时,实验Jurkat细胞和对照Jurkat细胞之间的生存力没有显着差异。值得注意的是,Jurkat细胞似乎比耐多药的克隆Jurkat / A4细胞更不容易凋亡,而细胞周期分析显示,RPM分别在72和96 h后,S期的Jurkat / A4细胞百分比增加了-模拟相对于其静态对应物的微重力。静态和模拟微重力之间所有阶段的Jurkat细胞差异均不显着。暴露于RPM后,Jurkat / A4细胞的细胞间粘附分子3(ICAM-3)(也称为分化簇(CD)50-蛋白)的表面表达发生了变化。 RPM模拟微重力96 h后,在Jurkat / A4细胞中观察到细胞形态的变化。因此,我们得出的结论是,与亲本Jurkat细胞系相比,Jurkat / A4细胞对RPM模拟的微重力更敏感。我们还建议细胞间粘附分子3可能是参与白细胞凋亡诱导的重要粘附分子。具有获得的多药耐药表型的Jurkat / A4细胞可能是研究模拟微重力作用和测试抗癌药物的有用模型。
  • 【三种随机效应方法的比较,以分析重复的有限结果得分,并将其应用于中风再验证研究中。】 复制标题 收藏 收藏
    DOI:10.1002/sim.3432 复制DOI
    作者列表:Molas M,Lesaffre E
    BACKGROUND & AIMS: :Discrete bounded outcome scores (BOS), i.e. discrete measurements that are restricted on a finite interval, often occur in practice. Examples are compliance measures, quality of life measures, etc. In this paper we examine three related random effects approaches to analyze longitudinal studies with a BOS as response: (1) a linear mixed effects (LM) model applied to a logistic transformed modified BOS; (2) a model assuming that the discrete BOS is a coarsened version of a latent random variable, which after a logistic-normal transformation, satisfies an LM model; and (3) a random effects probit model. We consider also the extension whereby the variability of the BOS is allowed to depend on covariates. The methods are contrasted using a simulation study and on a longitudinal project, which documents stroke rehabilitation in four European countries using measures of motor and functional recovery.
    背景与目标: :离散有界结果分数(BOS),即在有限的时间间隔内进行的离散测量,通常在实践中会出现。示例包括合规性措施,生活质量措施等。在本文中,我们研究了三种相关的随机效应方法,以BOS作为响应来分析纵向研究:(1)将线性混合效应(LM)模型应用于经逻辑转换的改良BOS ; (2)假设离散BOS是潜在随机变量的粗化版本的模型,在对数正态变换之后,该模型满足LM模型; (3)随机效应概率模型。我们还考虑了扩展,即BOS的可变性取决于协变量。通过模拟研究和一个纵向项目对这些方法进行了对比,该项目记录了四个欧洲国家中运动恢复和功能恢复的卒中康复情况。
  • 【交变电场阻止动物肿瘤模型和人脑肿瘤中的细胞增殖。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.0702916104 复制DOI
    作者列表:Kirson ED,Dbalý V,Tovarys F,Vymazal J,Soustiel JF,Itzhaki A,Mordechovich D,Steinberg-Shapira S,Gurvich Z,Schneiderman R,Wasserman Y,Salzberg M,Ryffel B,Goldsher D,Dekel E,Palti Y
    BACKGROUND & AIMS: :We have recently shown that low intensity, intermediate frequency, electric fields inhibit by an anti-microtubule mechanism of action, cancerous cell growth in vitro. Using implanted electrodes, these fields were also shown to inhibit the growth of dermal tumors in mice. The present study extends these findings to additional cell lines [human breast carcinoma; MDA-MB-231, and human non-small-cell lung carcinoma (H1299)] and to animal tumor models (intradermal B16F1 melanoma and intracranial F-98 glioma) using external insulated electrodes. These findings led to the initiation of a pilot clinical trial of the effects of TTFields in 10 patients with recurrent glioblastoma (GBM). Median time to disease progression in these patients was 26.1 weeks and median overall survival was 62.2 weeks. These time to disease progression and OS values are more than double the reported medians of historical control patients. No device-related serious adverse events were seen after >70 months of cumulative treatment in all of the patients. The only device-related side effect seen was a mild to moderate contact dermatitis beneath the field delivering electrodes. We conclude that TTFields are a safe and effective new treatment modality which effectively slows down tumor growth in vitro, in vivo and, as demonstrated here, in human cancer patients.
    背景与目标: :我们最近发现,低强度,中频电场会通过抗微管作用机制抑制体外癌细胞的生长。使用植入的电极,还显示了这些电场可抑制小鼠皮肤肿瘤的生长。本研究将这些发现扩展到其他细胞系[人乳腺癌; MDA-MB-231和人非小细胞肺癌(H1299)]和动物肿瘤模型(皮内B16F1黑色素瘤和颅内F-98胶质瘤)使用外部绝缘电极。这些发现导致了TTFields在10例复发性胶质母细胞瘤(GBM)患者中的临床试验试验的启动。这些患者疾病进展的中位时间为26.1周,中位总生存期为62.2周。这些疾病进展时间和OS值是历史对照组患者报告中位数的两倍以上。在所有患者中,> 70个月的累积治疗后,均未发现与器械相关的严重不良事件。看到的唯一与设备相关的副作用是在电场传递电极下方的轻度至中度接触性皮炎。我们得出的结论是,TTFields是一种安全有效的新治疗方式,可有效减缓体外,体内以及人类癌症患者体内肿瘤的生长。
  • 【泰国腐霉临床分离株的随机扩增多态性DNA分型和系统发育。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Pannanusorn S,Chaiprasert A,Prariyachatigul C,Krajaejun T,Vanittanakom N,Chindamporn A,Wanachiwanawin W,Satapatayavong B
    BACKGROUND & AIMS: :Forty-three Pythium insidiosum clinical isolates recovered from human pythiosis cases in Thailand were characterized by random amplified polymorphic DNA (RAPD) analysis. Three random oligonucleotide primers, OPW11, OPW12 and OPX13 generated 39, 34 and 35 DNA patterns with high value of typeability (100%), reproducibility (98.5, 88.8 and 93.3%) and discriminatory power (0.83, 0.82 and 0.77), respectively. Using GelCompar software based on band similarity, the 43 clinical isolates of P. insidiosum could be arranged into 9, 13 and 11 clades using OPW11, OPW12 and OPX13, respectively and the combination of all three primers revealed 36 RAPD patterns. Members in each RAPD pattern varied in both clinical forms and/or geographical locations. RAPD pattern 15 was found in 6 isolates, half of which were found in central region of Thailand. Isolates MCC15 and MCC16 isolated from different patients exhibited identical pattern with all three primers. Our results revealed high genetic heterogeneity among Pythium insidiosum isolates in Thailand. RAPD method should be appropriate for future epidemiological studies of P. insidiosum strains from patients and from natural habitats.
    背景与目标: :通过随机扩增多态性DNA(RAPD)分析表征了从泰国的人化脓毒症病例中回收到的43株Pythium insidiosum临床分离株。三种随机寡核苷酸引物OPW11,OPW12和OPX13分别产生39、34和35个DNA模式,分别具有高的可打字性(100%),可重复性(98.5、88.8%和93.3%)和鉴别力(0.83、0.82和0.77)。使用基于条带相似性的GelCompar软件,可以使用OPW11,OPW12和OPX13将43种In.diodiosum临床分离株分别排列成9个,13个和11个进化枝,所有这三种引物的组合显示出36种RAPD模式。每种RAPD模式的成员在临床形式和/或地理位置方面都有所不同。在6个分离株中发现了RAPD模式15,其中一半在泰国中部地区发现。分离自不同患者的MCC15和MCC16的所有三种引物均显示出相同的模式。我们的结果表明泰国泰国腐霉分离株具有很高的遗传异质性。 RAPD方法应适合于来自患者和自然栖息地的印度隐杆线虫菌株的未来流行病学研究。
  • 【景观尺度的空间丰度分布将核心与北方湖泊浮游细菌的随机成分区分开来。】 复制标题 收藏 收藏
    DOI:10.1111/ele.12704 复制DOI
    作者列表:Niño-García JP,Ruiz-González C,Del Giorgio PA
    BACKGROUND & AIMS: :Aquatic bacterial communities harbour thousands of coexisting taxa. To meet the challenge of discriminating between a 'core' and a sporadically occurring 'random' component of these communities, we explored the spatial abundance distribution of individual bacterioplankton taxa across 198 boreal lakes and their associated fluvial networks (188 rivers). We found that all taxa could be grouped into four distinct categories based on model statistical distributions (normal like, bimodal, logistic and lognormal). The distribution patterns across lakes and their associated river networks showed that lake communities are composed of a core of taxa whose distribution appears to be linked to in-lake environmental sorting (normal-like and bimodal categories), and a large fraction of mostly rare bacteria (94% of all taxa) whose presence appears to be largely random and linked to downstream transport in aquatic networks (logistic and lognormal categories). These rare taxa are thus likely to reflect species sorting at upstream locations, providing a perspective of the conditions prevailing in entire aquatic networks rather than only in lakes.
    背景与目标: :水生细菌群落包含成千上万个并存的类群。为了应对区分这些群落的“核心”和偶发性“随机”组成部分的挑战,我们探索了198个北方湖泊及其相关河流网络(188条河流)中单个浮游生物类群的空间丰度分布。我们发现,根据模型统计分布(正态,双峰,对数和对数正态),可以将所有分类单元分为四个不同的类别。湖泊及其相关河网之间的分布模式表明,湖泊群落由一个分类单元的核心组成,其分布似乎与湖内环境分类(类常态和双峰类)有关,并且大部分是稀有细菌(占所有分类单元的94%),其出现在很大程度上似乎是随机的,并且与水生网络(后勤和对数正态类别)中的下游运输有关。因此,这些稀有的分类单元很可能反映了上游地区的物种分类,从而提供了整个水生网络而不是仅湖泊中普遍存在的状况的视角。
  • 【使用深度变分自动编码器估算青光眼的进展速度并预测未来的视野。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-019-54653-6 复制DOI
    作者列表:Berchuck SI,Mukherjee S,Medeiros FA
    BACKGROUND & AIMS: :In this manuscript we develop a deep learning algorithm to improve estimation of rates of progression and prediction of future patterns of visual field loss in glaucoma. A generalized variational auto-encoder (VAE) was trained to learn a low-dimensional representation of standard automated perimetry (SAP) visual fields using 29,161 fields from 3,832 patients. The VAE was trained on a 90% sample of the data, with randomization at the patient level. Using the remaining 10%, rates of progression and predictions were generated, with comparisons to SAP mean deviation (MD) rates and point-wise (PW) regression predictions, respectively. The longitudinal rate of change through the VAE latent space (e.g., with eight dimensions) detected a significantly higher proportion of progression than MD at two (25% vs. 9%) and four (35% vs 15%) years from baseline. Early on, VAE improved prediction over PW, with significantly smaller mean absolute error in predicting the 4th, 6th and 8th visits from the first three (e.g., visit eight: VAE8: 5.14 dB vs. PW: 8.07 dB; P < 0.001). A deep VAE can be used for assessing both rates and trajectories of progression in glaucoma, with the additional benefit of being a generative technique capable of predicting future patterns of visual field damage.
    背景与目标: :在此手稿中,我们开发了一种深度学习算法,以改善青光眼的进展率估计和未来视野丧失模式的预测。训练了通用变分自动编码器(VAE),以使用来自3,832位患者的29,161个视野来学习标准自动视野(SAP)视野的低维表示。在90%的数据样本上对VAE进行了训练,并在患者水平上进行了随机分配。使用剩余的10%,生成进展和预测的速率,并分别与SAP平均偏差(MD)速率和逐点(PW)回归预测进行比较。在距基线两年(25%vs. 9%)和四年(35%vs 15%)的年份,通过VAE潜在空间的纵向变化率(例如,具有八个维度)检测到的进展比例明显高于MD。早期,VAE改进了PW的预测,从前三个中预测第4、6和8次访问时的平均绝对误差明显较小(例如,访问八次:VAE8:5.14 dB,而PW:8.07 dB; P <0.001)。深度VAE可用于评估青光眼的进展速度和轨迹,其另外的好处是能够预测未来视野损害模式的生成技术。
  • 【通过随机扩增多态性DNA分析法快速鉴定斑驳杆菌的遗传变异和致病型。】 复制标题 收藏 收藏
    DOI:10.1128/AEM.57.9.2482-2486.1991 复制DOI
    作者列表:Goodwin PH,Annis SL
    BACKGROUND & AIMS: :Canadian isolates of Leptosphaeria maculans, the causal agent of blackleg of crucifers, were examined for genetic relatedness by the random amplified polymorphic DNA assay. DNA polymorphisms amplified with random decamer primers were used to distinguish three groups of isolates. Group 1 contained all isolates of the virulent pathotype, group 2 contained isolates of the avirulent pathotype from western Canada, and group 3 contained avirulent pathotype isolates from Ontario. These results agreed with other reports which showed many genetic differences between pathotypes and were consistent with the hypothesis that the virulent pathotype was recently introduced into Canada and has diverged relatively little. In contrast, the avirulent pathotype has probably been present in Canada for a longer time and has diverged with geographic isolation. In addition to establishing genetic relationships, DNA fingerprints generated by the random amplified polymorphic DNA assay have potential applications in pathotype identification and blackleg disease management.
    背景与目标: :通过随机扩增多态性DNA分析法检测了十字花科黑脚病的致病病原体,加拿大黑斑病杆菌的分离株。用随机十聚体引物扩增的DNA多态性用于区分三类分离株。第1组包含所有毒力致病型的分离株,第2组包含来自加拿大西部的无毒致病型的分离株,第3组包含来自安大略省的无毒致病型的分离株。这些结果与其他报告一致,这些报告显示了致病型之间存在许多遗传差异,并且与强毒型最近被引入加拿大且差异相对较小的假说相符。相反,无毒病原体型可能在加拿大已经存在了较长时间,并且随着地理隔离而有所不同。除了建立遗传关系外,由随机扩增的多态性DNA分析产生的DNA指纹在病理类型识别和黑腿病管理中也有潜在的应用。

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