Characterization of bright betatron radiation generated by direct laser acceleration of electrons in plasma of near critical density

Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the process of direct laser acceleration (DLA) of electrons in a relativisticlaser channel when the electrons undergo transverse betatron oscillations in self-generated quasi-static electric and magnetic fields. In anexperiment at the PHELIX laser system, high-current directed beams of DLA electrons with a mean energy ten times higher than the ponderomotive potential and maximum energy up to 100 MeV were measured at 10^(19) W/cm^(2)laser intensity. The spectrum of directed x-raysin the range of 5–60 keV was evaluated using two sets of Ross filters placed at 0°and 10°to the laser pulse propagation axis. The differential x-ray absorption method allowed for absolute measurements of the angular-dependent photon fluence. We report 10^(13) photons/sr withenergies >5 keV measured at 0°to the laser axis and a brilliance of 10^(21) photons s^(−1) mm^(−2) mrad−2(0.1%BW)−1. The angular distributionof the emission has an FWHM of 14°–16°. Thanks to the ultra-high photon fluence, point-like radiation source, and ultra-short emissiontime, DLA-based keV backlighters are promising for various applications in high-energy-density research with kilojoule petawatt-class laserfacilities.

Graphene-calcium carbonate coating to improve the degradation resistance and mechanical integrity of a biodegradable implant

Biodegradable implants are critical for regenerative orthopaedic procedures,but they may suffer from too fast corrosion in human-body environment.This necessitates the synthesis of a suitable coating that may improve the corrosion resistance of these implants without compromising their mechanical integrity.In this study,an AZ91 magnesium alloy,as a representative for a biodegradable Mg implant material,was modified with a thin reduced graphene oxide(RGO)-calcium carbonate(CaCO_(3))composite coating.Detailed analytical and in-vitro electrochemical characterization reveals that this coating significantly improves the corrosion resistance and mechanical integrity,and thus has the potential to greatly extend the related application field.

A digital microfluidic single-cell manipulation systemoptimized by extending-depth-of-field device

Microfuidic systems have been widely utilized in high-throughput biology analysis,but thedificulties in iquid manipulation and cell cultivation limit its application.This work has developed a new digital microfluidic(DMF)system for on-demand droplet control.By adopting anextending-depth-of-field(EDoF)phase modulator to the optical system,the entire depth of themicrofluidic channel can be covered in one image without any refocusing process,ensuring that 95%of the particles in the droplet are captured within three shots together with shaking pro-cesses.With this system,suspension droplets are generated and droplets containing only oneyeast cll can be recognized,then each single cell is cultured in the array of the chip.Byobservingtheir growth in cell numbers and the green fluorescence protein(GFP)production via fluorescence imaging,the single cell with the highest production can be identified.The results haveproved the heterogeneity of yeast cells,and showed that the combined system can be applied forrapid single-cell sorting,cultivation,and analysis.

塔里木盆地寒武纪—奥陶纪优质烃源岩沉积与古环境变化的关系:碳氧同位素新证据

对塔里木盆地东部塔东2井上震旦统和寒武系—奥陶系样品进行TOC和碳、氧同位素及微量元素分析,发现该井稳定碳、氧同位素值在寒武系—中奥陶统发生明显变化,该层还赋存高有机质丰度烃源岩,其TOC值的高低可反映当时的生物产率和埋藏率。碳和氧同位素值在寒武系/上震旦统分界处正向漂移,说明正好在进入寒武纪前气候明显变冷,海平面下降。接着,下寒武统底部以碳和氧同位素值的快速负向漂移为标志,表明古气候迅速变暖和海平面大幅度上升,烃源岩TOC值也达到全井柱最高值。古气候显著波动、海平面最高及其频繁变化和沉积物高TOC是早寒武世的显著特征;而晚寒武世—早奥陶世,同位素正向漂移,暗示海平面下降,沉积物TOC也随之下降并降至最低;到了早奥陶世末,即早、中奥陶世的过渡时期,同位素又开始负向漂移,TOC又开始升高;中奥陶世,同位素强烈负向漂移,TOC又升至新高。稳定碳、氧同位素值的变化及其所指示的古气候与海平面变化,以及与TOC的响应关系,指示冰期、冰后期之交,古气候迅速变暖和海平面大幅度上升有利于烃源岩发育;同时暗示,δ13C、δ18O与生烃母质生物的有机生产率、有机埋藏率之间存在某种内在联系。即高TOC含量反映高的有机生产率和高的有机埋藏率;而与其同步反方向变化的δ13C、δ18O则暗示海平面较高,沉积环境属远陆海域,表层水中生烃母质生物的光合作用很强。而有机质的高产率和高埋藏率,导致海水中δ12C和δ16O被大量地固定在沉积物中。这样,就使海水中相对富集13C和18O重同位素而使海水变“重”;而这种“重”海水,又导致了同时期浅水区碳酸盐沉积物的δ13C和δ18O值明显增高。

蒙其古尔铀矿床砂岩型铀矿生物成矿作用探讨

蒙其古尔铀矿床是伊犁盆地南缘铀资源量最大的砂岩型铀矿床,关于该矿床的成因机理,也一直是铀矿地质学界关注的焦点。通过对该矿床含矿地层的地球化学特征、黏土矿物特征进行分析研究,以及对黄铁矿硫同位素的分析测试,认为在铀成矿过程中有还原物质的参与,而且该还原物质与生物作用有一定关系。生物作用参与成矿可能是蒙其古尔铀矿床矿体品位较高的重要原因。

家族性肌萎缩侧索硬化症转基因鼠的繁殖和鉴定

目的建立家族性肌萎缩侧索硬化症(FALS)转基因模型鼠的繁育方法,并对其子代鼠进行基因鉴定。方法(1)以6只B6SJL SOD1G93A/+半合子雄鼠与6只B6SJLF1/J+/+雌鼠(1∶1)交配;(2)由鼠尾血提取基因组DNA,PCR扩增hmSOD1基因的片段,电泳后观察结果;(3)对PCR产物进行纯化测序,并通过BLAST验证。结果6对种鼠交配产鼠仔53只,存活率为98%(52/53);G93A hmSOD1阳性鼠约占44.2%(23/52);PCR扩增产物分别为内对照(IL-2):324 bp;Tg(hmSOD1):236 bp;测序证实PCR产物的基因序列和hmSOD1基因片段中的序列一致,并存在G93A突变。结论B6SJL-Tg(SOD1-G93A)1Gur/J雄鼠与B6SJLF1/J雌鼠配种能成功繁育出Tg(hmSOD1)阳性的ALS半合子子代鼠;本实验的PCR法能准确鉴定hmSOD1基因阳性鼠,并证实该转入的基因按近似孟德尔方式遗传,为ALS实验研究奠定了基础。

人类鼻咽癌细胞株CNE2的转化基因Tx的一个Eco RI片段的核苷酸序列分析

本文运用定点克隆法并结合鸟枪法,对人类鼻咽癌细胞抹CNE2转化基因Tx中一个与转化作用有关的Eco RI片段,进行了核苷酸序列分析。此种克隆方法的运用,大大减少了DNA模板的数量,并加快了测序的进展。将序列分析结果输入美国NCI的CRAY-2型超级电子计算机作进一步分析,以寻找基因库中的同源序列,酶切位点,开放阅读框架(ORF)。在人类DNA基因数据库中没有找到同源序列,从而证实Tx基因是一种新的人类转化基因。计算机的分析还得出了一系列有价值的结论,为进一步深入探讨这个基因在人类鼻咽癌发病学中的作用,提供了重要的资料。这是首次报道的Tx基因核苷酸序列分析结果。

水井反冲洗地层三维弹塑性固结分析

注水井反冲洗工艺是抽油机井维持正常生产的重要措施之一,反冲洗压力是决定反冲洗效率的主要因素。反冲洗过程涉及到地层与套管在水压作用下的相互耦合作用,鉴于目前对洗井压力的制定以套管抗挤压强度为依据,运用ABAQUS-6.5软件,对油藏岩石-套管进行了三维弹塑性固结有限元分析,建立了流-固耦合数学模型,研究了注水井反冲洗过程中套管、地层和流体的瞬态响应,实现了套管、地层和流体间的耦合作用,得到了套管应力随洗井时间的变化规律。计算结果表明,洗井地层的地应力分布状态和地层性质对洗井压力影响较大,主要受到地层弹性模量、渗透性能和地层水平地应力的影响。洗井压力的制定应综合考虑套管和地层状况,与单纯考虑套管的承载能力相比,其研究结果可为洗井工艺的制定提供更为准确的理论基础。

碳化钽粉末的爆炸成形方法

碳化钽熔点为3880℃,是地球上第二高熔点的物质.其抗腐蚀性能优越,在航空领域有广阔的应用空间.但是传统的材料加工方法,比如热压或者热等静压,会导致晶粒快速长大而得到低的断裂韧性.本文利用爆破方法来克服晶粒长大问题,得到强度和断裂韧性高的碳化钽.碳化钽颗粒直径小于3μm,组成晶粒为0.5～1μm,填充到双层钢管进行爆炸处理.在钢管的底部发现碳化钽试样几乎达到理论密度,但是该区域裂纹较多,硬度测得为15 GPa,和文献报道的碳化钽理论硬度相同.在钢管的中部的试样密度为理论密度的85%,这个区域没有发现裂纹.之后的旨在提高试样密度热处理中,发现了其烧结特征发生改善.经分析是因为爆炸使碳化钽粉末的颗粒内部产生内应力,而使其扩散激活能降低的结果.

微波处理玄武岩强度的SPH-FEM耦合算法模拟

微波预处理弱化岩体强度,进而降低机械破岩过程中的钻头/刀具磨损、提升凿岩效率已经成为一项极具前景的技术。为探究数值模拟参数对岩石静强度模拟结果的影响,并为后续钻凿或岩石切割模拟确定合理的微波处理玄武岩数值力学参数,采用光滑粒子流体动力学与有限元耦合算法(SPH-FEM)构建岩石单轴压缩与巴西拉伸数值模型。为减小微波损伤对岩石强度测试误差的影响,采用线性莫尔-库仑理论对相同微波参数下微波处理玄武岩试样的黏聚力和内摩擦角进行标定。在单轴抗压与巴西拉伸模拟过程中开展SPH关键控制参数的敏感性分析,并根据同一组校核后的黏聚力和内摩擦角数据,在数值实验中同时捕获目标抗压强度与巴西拉伸强度,单轴抗压强度数值模拟结果与试验结果吻合较好。此外,结合数值模拟结果评估微波辐照参数对玄武岩力学行为的影响。

大豆体细胞胚系培养及其微卫星DNA稳定性研究(简报)

植物离体培养是植物基因操作中的重要一环．也是植物个体发育研究中基因表达研究的有益参考体系。在继代培养过程中发生的遗传变异有时会使再生植株丧失优良的性状而需加以控制和避免。为此，首先需要了解培养过程中的遗传变异情况。

Predictive value of multi-detector computed tomography for accurate diagnosis of serous cystadenoma:Radiologic-pathologic correlation

AIM:To identify multi-detector computed tomography(MDCT) features most predictive of serous cystadenomas(SCAs),correlating with histopathology,and to study the impact of cyst size and MDCT technique on reader performance.METHODS:The MDCT scans of 164 patients with surgically verified pancreatic cystic lesions were reviewed by two readers to study the predictive value of various morphological features for establishing a diagnosis of SCAs.Accuracy in lesion characterization and reader conf idence were correlated with lesion size(≤3cm or≥3cm) and scanning protocols(dedicated vs routine).RESULTS:28/164 cysts(mean size,39 mm;range,8-92mm) were diagnosed as SCA on pathology.The MDCT features predictive of diagnosis of SCA were microcystic appearance(22/28,78.6%),surface lobulations(25/28,89.3%) and central scar(9/28,32.4%).Stepwise logistic regression analysis showed that only microcystic appearance was signifi cant for CT diagnosis of SCA(P=0.0001).The sensitivity,specificity and PPV of central scar and of combined microcystic appearance and lobulations were 32.4%/100%/100% and 68%/100%/100%,respectively.The reader confidence was higher for lesions>3cm(P=0.02) and for MDCT scans performed using thin collimation(1.25-2.5mm) compared to routine 5 mm collimation exams(P>0.05).CONCLUSION:Central scar on MDCT is diagnostic of SCA but is seen in only one third of SCAs.Microcystic morphology is the most significant CT feature in diagnosis of SCA.A combination of microcystic appearance and surface lobulations offers accuracy comparable to central scar with higher sensitivity.

智能代理在油藏建模中的应用

利用人工智能和机器学习技术,采用人工神经网络开发并验证了用于油藏模拟历史拟合、敏感性分析和不确定性评估的智能代理模型,将其应用于油藏模拟的两个案例中。第1个案例研究了代理模型在油藏模型历史拟合中的应用,输出结果预测了井的产量;第2个案例研究了基于人工神经网络的代理模型在CO2提高采收率油藏快速建模中的应用,目标为预测油藏压力和相饱和度在注入期间以及注入后的分布,预测效果均良好。相比基础数值模拟模型,智能代理模型运行单次模拟只需几秒钟,总节省98.9%的运算时间。智能代理模型在运算速度、消耗时间以及成本等方面都有巨大的优势。此外,智能代理模型与基础油藏模型模拟结果非常接近。

镍钼杂多酸制备NiMo/γ-Al_2O_3催化剂及硼、钴或镍改性氧化铝的影响(英文)

A hydrotreating NiMo/γ-Al2O3 catalyst(12 wt% Mo and 1.1 wt% Ni) was prepared by impregnation of the support with the Anderson-type heteropolyoxomolybdate(NH4)4Ni(OH)6Mo6O18.Before impregnation of the support,it was modified with an aqueous solution of H3BO3,Co(NO3)2,or Ni(NO3)2.The catalysts were investigated using N2 adsorption,O2 chemisorption,X-ray diffraction,UV-Vis spectroscopy,Fourier transform infrared spectroscopy,temperature-programmed reduction,temperature-programmed desorption,and X-ray photoelectron spectroscopy.The addition of Co,Ni,or B influenced the Al2O3 phase composition and gave increased catalytic activity for 1-benzothiophene hydrodesulfurization(HDS).X-ray photoelectron spectroscopy confirmed that the prior loading of Ni,Co or B increased the degree of sulfidation of the NiMo/γ-Al2O3 catalysts.The highest HDS activity was observed with the NiMo/γ-Al2O3 catalyst with prior loaded Ni.

In situ tumor vaccination with adenovirus vectors encoding measles virus fusogenic membrane proteins and cytokines

AIM: To evaluate whether intratumoral expression of measles virus fusogenic membrane glycoproteins H and F (MV-FMG), encoded by an adenovirus vector Ad.MV-H/ F, alone or in combination with local coexpression of cytokines (IL-2, IL-12, IL-18, IL-21 or GM-CSF), can serve as a platform for inducing tumor-specifi c immune responses in colon cancer. METHODS: We used confocal laser scanning microscopy and flow cytometry to analyze cell-cell fusion after expression of MV-FMG by dye colocalization. In a syngeneic bilateral subcutaneous MC38 and Colon26 colon cancer model in C57BL/6 and BALB/c mice, we assessed the effect on both the directly vector-treated tumor as well as the contralateral, not directly vector- treated tumor. We assessed the induction of a tumor- specific cytotoxic T lymphocyte (CTL) response with a lactate dehydrogenase (LDH) release assay. RESULTS: We demonstrated in vitro that transduction of MC38 and Colon26 cells with Ad.MV-H/F resulted in dye colocalization, indicative of cell-cell fusion. In addition, in the syngeneic bilateral tumor model we demonstrated a signifi cant regression of the directly vector-inoculated tumor upon intratumoral expression of MV-FMG alone or in combination with the tested cytokines. We observed the highest anti-neoplastic efficacy with MV-FMG and IL-21 coexpression. The degree of tumor regression of the not directly vector-treated tumor correlated with the anti-neoplastic response of the directly vector-treated tumor. This regression was mediated by a tumor-specifi c CTL response. CONCLUSION: Our data indicate that intratumoral expression of measles virus fusogenic membraneglycoproteins is a promising tool both for direct tumor treatment as well as for tumor vaccination approaches that can be further enhanced by cytokine coexpression.

Full field reservoir modeling of shale assets using advanced data-driven analytics

Hydrocarbon production from shale has attracted much attention in the recent years. When applied to this prolific and hydrocarbon rich resource plays, our understanding of the complexities of the flow mechanism（sorption process and flow behavior in complex fracture systems- induced or natural） leaves much to be desired. In this paper, we present and discuss a novel approach to modeling, history matching of hydrocarbon production from a Marcellus shale asset in southwestern Pennsylvania using advanced data mining, pattern recognition and machine learning technologies. In this new approach instead of imposing our understanding of the flow mechanism, the impact of multi-stage hydraulic fractures, and the production process on the reservoir model, we allow the production history, well log, completion and hydraulic fracturing data to guide our model and determine its behavior. The uniqueness of this technology is that it incorporates the so-called ＂hard data＂ directly into the reservoir model, so that the model can be used to optimize the hydraulic fracture process. The ＂hard data＂ refers to field measurements during the hydraulic fracturing process such as fluid and proppant type and amount, injection pressure and rate as well as proppant concentration. This novel approach contrasts with the current industry focus on the use of ＂soft data＂（non-measured, interpretive data such as frac length, width,height and conductivity） in the reservoir models. The study focuses on a Marcellus shale asset that includes 135 wells with multiple pads, different landing targets, well length and reservoir properties. The full field history matching process was successfully completed using this data driven approach thus capturing the production behavior with acceptable accuracy for individual wells and for the entire asset.

Identification of the varietal origin of processed loose-leaf tea based on analysis of a single leaf by SNP nanofluidic array

Tea is an important cash crop, representing a $40 billion-a-year global market. Differentiation of the tea market has resulted in increasing demand for tea products that are sustainably and responsibly produced. Tea authentication is important because of growing concerns about fraud involving premium tea products. Analytical technologies are needed for protection and value enhancement of high-quality brands. For loose-leaf teas, the challenge is that the authentication needs to be established on the basis of a single leaf, so that the products can be traced back to the original varieties. A new generation of molecular markers offers an ideal solution for authentication of processed agricultural products. Using a nanofluidic array to identify variant SNP sequences, we tested genetic identities using DNA extracted from single leaves of 14 processed commercial tea products. Based on the profiles of 60 SNP markers, the genetic identity of each tea sample was unambiguously identified by multilocus matching and ordination analysis. Results for repeated samples of multiple tea leaves from the same products(using three independent DNA extractions) showed 100% concordance, showing that the nanofluidic system is a reliable platform for generating tea DNA fingerprints with high accuracy. The method worked well on green, oolong, and black teas, and can handle a large number of samples in a short period of time. It is robust and cost-effective, thus showing high potential for practical application in the value chain of the tea industry.

3.0 T高空间分辨力MR下肢血管成像对比剂剂量的对照性研究

目的明确在3．0T设备上行下肢高空间分辨力MR血管成像时，是否可在对比剂剂量减少的情况下仍保持较好的影像质量。方法45例病人（男27例，女18例；平均年龄64岁）在3．0T设备上行下肢增强MR血管成像检查。本研究经学院伦理委员会批准可免除知情同意书。16例采用高剂量（约0．3mmol／kg），15例采用中等剂量（约0．2mmol／kg），14例采用低剂量（约0．1mmol／kg）的马根维显溶液进行3站双相注射检查。将动脉系统从腹腔干到跖动脉分成34个节段评定积分。

生物人类学和人体组成学的渊源关系

随着人体组成学中文版的发行和人体组成测量培训班在中国的举行,中国生物人类学家对人体组成测量方法在科研中的运用有了更大的兴趣。该文对人类学家,如Jind ich Matiegka和Stanley MarionGarn在人体组成学发展中的历史贡献做了基本的介绍。此外,作者还以Garn博士的工作为例,去激励中国生物人类学家开展人体组成学的研究工作。文章讨论了人体组成成分的测量方法在生物人类学中的用途,并介绍了人体组成学的基本理论和概念及近年来人体组成学的变化:如影像技术的发展,影像技术作为"金标准"对评估其他人体组成测量方法的用途,双能量x线吸收法的优势,生物电阻分析法的广泛运用,和多种人体组成测量方法相辅相成的现象。作者对常用的人体组成测量方法的优缺点做了比较,并指出人体组成成分测量是人体测量方法的自然延续,人体组成学和生物人类学的关系渊源已久;因此中国人类学家应当更多地利用人体组成测量方法对人体差异做更深入的研究,并注重人体差异同健康疾病和生物医学的关系,以便让生物人类学更好地为当今社会服务。

Effect of fire severity on physical and biochemical soil properties in Zagros oak(Quercus brantii Lindl.)forests in Iran

Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity： low （LS）, high （HS） and medium severity （MS）, and unburned （UB）, which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide, and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchange capacity, accessible phosphorus, accessible potassium, bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physicalchemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned.