• 【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。
  • 【磁场,导线代码和儿童白血病的汇总分析。儿童白血病-EMF研究小组。】 复制标题 收藏 收藏
    DOI:10.1097/00001648-200011000-00003 复制DOI
    作者列表:Greenland S,Sheppard AR,Kaune WT,Poole C,Kelsh MA
    BACKGROUND & AIMS: :We obtained original individual data from 15 studies of magnetic fields or wire codes and childhood leukemia, and we estimated magnetic field exposure for subjects with sufficient data to do so. Summary estimates from 12 studies that supplied magnetic field measures exhibited little or no association of magnetic fields with leukemia when comparing 0.1-0.2 and 0.2-0.3 microtesla (microT) categories with the 0-0.1 microT category, but the Mantel-Haenszel summary odds ratio comparing >0.3 microT to 0-0.1 microT was 1.7 (95% confidence limits = 1.2, 2.3). Similar results were obtained using covariate adjustment and spline regression. The study-specific relations appeared consistent despite the numerous methodologic differences among the studies. The association of wire codes with leukemia varied considerably across studies, with odds ratio estimates for very high current vs low current configurations ranging from 0.7 to 3.0 (homogeneity P = 0.005). Based on a survey of household magnetic fields, an estimate of the U.S. population attributable fraction of childhood leukemia associated with residential exposure is 3% (95% confidence limits = -2%, 8%). Our results contradict the idea that the magnetic field association with leukemia is less consistent than the wire code association with leukemia, although analysis of the four studies with both measures indicates that the wire code association is not explained by measured fields. The results also suggest that appreciable magnetic field effects, if any, may be concentrated among relatively high and uncommon exposures, and that studies of highly exposed populations would be needed to clarify the relation of magnetic fields to childhood leukemia.
    背景与目标: :我们从15项磁场或电码和儿童白血病研究中获得了原始的个人数据,并估计了具有足够数据的受试者的磁场暴露量。比较提供0.1-0.2和0.2-0.3 microtesla(microT)类别与0-0.1 microT类别时,提供磁场测量的12项研究的汇总估计显示磁场与白血病几乎没有关联,但Mantel-Haenszel汇总优势比是将> 0.3 microT与0-0.1 microT进行比较为1.7(95%置信限= 1.2、2.3)。使用协变量调整和样条回归获得相似的结果。尽管研究之间在方法上存在许多差异,但特定于研究的关系似乎是一致的。在不同的研究中,导线代码与白血病之间的关联差异很大,极高电流与低电流配置的比值比估计值范围为0.7至3.0(均匀度P = 0.005)。根据对家庭磁场的调查,估计美国居民归因于居民暴露的儿童白血病的比例为3%(95%置信度= -2%,8%)。我们的结果与磁场与白血病的关联性不如电线编码与白血病的关联性相矛盾,尽管对这两种措施的四项研究的分析表明,电线编码的关联性并未由实测场解释。结果还表明,如果有的话,可能会有明显的磁场效应集中在相对较高和不常见的接触中,因此需要对高度接触的人群进行研究,以阐明磁场与儿童白血病的关系。
  • 【关于“直流和交流磁场对大分子离子运动的联合作用”的几点评论。】 复制标题 收藏 收藏
    DOI:10.1002/bem.20314 复制DOI
    作者列表:Binhi VN
    BACKGROUND & AIMS: :Zhadin and Barnes [2005:26:323-330] concluded that they solved the differential equation describing combined action of DC and AC magnetic fields on thermal motion of ions in a biological macromolecule and, as a result, a diversity of biological phenomena could be explained. It is shown here that biological phenomena cannot be explained based on this model. Adair [2006:27:332-334] gave several arguments for the statement that the interaction of weak magnetic fields with ions trapped in protein cavities cannot produce detectable biological effects through changing the character of the ion orbits. The arguments are analyzed here and some are shown to be questionable or unjustified. We stress the difference between the conclusion made by Adair and that stated in this article.
    背景与目标: :Zhadin and Barnes [2005:26:323-330]得出的结论是,他们解决了描述直流和交流磁场对离子在生物大分子中热运动的联合作用的微分方程,因此,多种生物现象可以被解释。在此表明,不能基于该模型来解释生物现象。 Adair [2006:27:332-334]提出了以下论点:弱磁场与蛋白质腔中捕获的离子的相互作用无法通过改变离子轨道的特性而产生可检测的生物学效应。本文对这些论点进行了分析,其中一些论点显示有问题或不合理。我们强调Adair得出的结论与本文所述结论之间的区别。
  • 【[通过加热或高强度脉冲电场(HIPEF)保存的基于橙汁和乳清粉的饮料的可接受性和营养品质]。】 复制标题 收藏 收藏
    DOI: 复制DOI
    作者列表:Mónico Pifarré A,Martín O,de Portela ML,Langini SH,Weisstaub AR,Greco C,de Ferrer PR
    BACKGROUND & AIMS: :Orange juice may be a nutrient vehicle that helps to improve diet quality. The addition of whey allows the incorporation of high quality proteins. However, a good acceptability is necessary. The aims of the present study were: a) to assess the acceptability of a beverage prepared with orange juice (J) and whey powder (WP) at 7 g/100 g (J+WP7) or at 13 g/100 g (J+WP13); b) to measure available lysine content and ascorbic acid retention of the more accepted formulation, comparing the effect of HIPEF treatment (29 kV/cm, t(acum): 59 micros) with a conventional heat treatment at 75 degrees C, for 15 minutes (HT). The beverages were subjected to sensory evaluation (Friedman test). Available lysine was assessed by the Carpenter method, modified by Booth, and vitamin C by HPLC; minerals Na and K, by flame photometry; Ca, Mg and Zn by atomic absorption spectrometry. There were no significant differences between the acceptance of J and J+WP7. J+WP13 was significantly less accepted (p < 0.01), so it was discarded. Available lysine (mg/g protein) in untreated J+WP7 was 60.2 +/- 0.15; after treatments: 50.0 +/- 2.8 (HT) and 51.0 +/- 3.4 (HIPEF). The HIPEF treated J and (J+WP7) retained 100% and 98% of their vitamin C initial content and the HT treated, 91% and 88%, respectively. The amount of whey powder added to the orange juice conditioned the acceptability. The juice containing 7% of whey powder was well accepted, and after treatment by HIPEF, it retained a good nutritional quality, regarding available lysine, vitamin C retention and provision of mineral nutrients.
    背景与目标: :橙汁可能是有助于改善饮食质量的营养载体。乳清的加入允许掺入高质量的蛋白质。但是,必须具有良好的可接受性。本研究的目的是:a)评估以7 g / 100 g(J WP7)或13 g / 100 g(J WP13)的橙汁(J)和乳清粉(WP)制备的饮料的可接受性); b)测量更可接受的配方中可用的赖氨酸含量和抗坏血酸保留率,将HIPEF处理(29 kV / cm,t(acum):59 micros)与传统的75°C热处理15分钟的效果进行比较(H T)。对饮料进行感官评估(弗里德曼测试)。可用赖氨酸通过Carpenter方法进行评估,经Booth修改,并通过HPLC评估维生素C;火焰光度法测定Na和K矿物;钙,镁和锌的原子吸收光谱法。 J和J WP7的接受之间没有显着差异。 J WP13的接受程度明显较低(p <0.01),因此将其丢弃。未经处理的J WP7中的可用赖氨酸(mg / g蛋白)为60.2 /-0.15;治疗后:50.0 /-2.8(HT)和51.0 /-3.4(HIPEF)。经HIPEF处理的J和(J WP7)保留了其维生素C初始含量的100%和98%,而经HT处理的J和(WP7)分别保留了91%和88%。添加到橙汁中的乳清粉的数量决定了可接受性。含有7%乳清粉的果汁被广泛接受,经过HIPEF处理后,就赖氨酸,维生素C的保留和矿物质营养的提供而言,它保持了良好的营养品质。
  • 【在随机环境中检测规律性。】 复制标题 收藏 收藏
    DOI:10.1177/1747021820941356 复制DOI
    作者列表:Rey A,Bogaerts L,Tosatto L,Bonafos G,Franco A,Favre B
    BACKGROUND & AIMS: :Regularity detection, or statistical learning, is regarded as a fundamental component of our cognitive system. To test the ability of human participants to detect regularity in a more ecological situation (i.e., mixed with random information), we used a simple letter-naming paradigm in which participants were instructed to name single letters presented one at a time on a computer screen. The regularity consisted of a triplet of letters that were systematically presented in that order. Participants were not told about the presence of this regularity. A variable number of random letters were presented between two repetitions of the regular triplet, making this paradigm similar to a Hebb repetition task. Hence, in this Hebb-naming task, we predicted that if any learning of the triplet occurred, naming times for the predictable letters in the triplet would decrease as the number of triplet repetitions increased. Surprisingly, across four experiments, detection of the regularity only occurred under very specific experimental conditions and was far from a trivial task. Our study provides new evidence regarding the limits of statistical learning and the critical role of contextual information in the detection (or not) of repeated patterns.
    背景与目标: :规律性检测或统计学习被视为我们认知系统的基本组成部分。为了测试人类参与者在更生态的情况下(例如,与随机信息混合)检测规律性的能力,我们使用了一种简单的字母命名范例,其中指示参与者命名在计算机屏幕上一次显示的单个字母。规则性由按字母顺序排列的三联字母组成。没有告诉参与者这种规律性的存在。在常规三联体的两次重复之间出现了可变数量的随机字母,使这种范例类似于Hebb重复任务。因此,在此Hebb命名任务中,我们预测,如果对三联体进行了任何学习,则随着三联体重复次数的增加,三联体中可预测字母的命名时间将减少。出乎意料的是,在四个实验中,规律性的检测仅在非常特定的实验条件下进行,而这绝非易事。我们的研究提供了有关统计学习的局限性以及上下文信息在检测(或不检测)重复模式中的关键作用的新证据。
  • 【使用噬菌体fUSE5随机肽库鉴定HLA-DR9(DRB1 * 0901)结合肽基序。】 复制标题 收藏 收藏
    DOI:10.1016/0198-8859(95)00169-7 复制DOI
    作者列表:Fujisao S,Matsushita S,Nishi T,Nishimura Y
    BACKGROUND & AIMS: We identified HLA-DRB1*0901-binding peptides by affinity-based selection of a phage random peptide library using the biotinylated DR9 complex. Analogue peptides with single amino acid residue substitutions of a DR9 binder revealed that two major anchors (WxxS, where x is any amino acid) play an essential role in binding to DR9. Determination of the binding affinity of synthetic wild-type-based analogue peptides showed that substituting W to F or L, and S to A, V, or F allow high affinity binding with DR9. Collectively, DR9-binding peptide motifs identified in this study are characteristic in that (a) only two anchors of the NH2-terminal half of binding peptides play important roles in binding, and (b) small neutral hydrophilic Ser is allowed as the second anchor for high-affinity binding, unlike the other DR-binding motifs heretofore reported. The implications of our results are discussed in light of the HLA-DR9-associated susceptibility to juvenile-onset myasthenia gravis and systemic lupus erythematosus with antiphospholipid syndrome, in particular, T-cell responses to autoantigens.

    背景与目标: 我们通过使用生物素化的DR9复合物的噬菌体随机肽库的基于亲和力的选择,确定了HLA-DRB1 * 0901结合肽。具有DR9结合物的单个氨基酸残基取代的类似物肽显示,两个主要锚(WxxS,其中x是任何氨基酸)在结合DR9中起着至关重要的作用。合成的基于野生型的类似物肽的结合亲和力的测定表明,将W替换为F或L,将S替换为A,V或F,可实现与DR9的高亲和力结合。总体而言,这项研究中确定的DR9结合肽基序具有以下特征:(a)结合肽的NH2末端一半只有两个锚点在结合中起重要作用,并且(b)允许使用小的中性亲水性Ser作为第二个锚点与迄今报道的其他DR-结合基序不同,其用于高亲和力结合。鉴于HLA-DR9对青少年发作性重症肌无力和系统性红斑狼疮伴抗磷脂综合征的易感性,特别是T细胞对自身抗原的反应,讨论了我们的研究结果的含义。

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