• 【具有集成光腔的类LED器件中的光泵浦胶体量子点激光。】 复制标题 收藏 收藏
    DOI:10.1038/s41467-019-14014-3 复制DOI
    作者列表:Roh J,Park YS,Lim J,Klimov VI
    BACKGROUND & AIMS: :Realization of electrically pumped lasing with solution processable materials will have a revolutionary impact on many disciplines including photonics, chemical sensing, and medical diagnostics. Due to readily tunable, size-controlled emission wavelengths, colloidal semiconductor quantum dots (QDs) are attractive materials for attaining this goal. Here we use specially engineered QDs to demonstrate devices that operate as both a light emitting diode (LED) and an optically pumped laser. These structures feature a distributed feedback resonator integrated into a bottom LED electrode. By carefully engineering a refractive-index profile across the device, we are able to obtain good confinement of a waveguided mode within the QD medium, which allows for demonstrating low-threshold lasing even with an ultrathin (about three QD monolayers) active layer. These devices also exhibit strong electroluminescence (EL) under electrical pumping. The conducted studies suggest that the demonstrated dual-function (lasing/EL) structures represent a promising device platform for realizing colloidal QD laser diodes.
    背景与目标: :用溶液可处理材料实现电泵浦激光技术将对包括光子学,化学传感和医学诊断在内的许多学科产生革命性的影响。由于易于调节尺寸,控制发射波长,胶体半导体量子点(QD)是实现此目标的有吸引力的材料。在这里,我们使用经过特殊设计的QD来演示既可以用作发光二极管(LED)也可以用作光泵浦激光器的设备。这些结构的特征是集成在底部LED电极中的分布式反馈谐振器。通过仔细设计整个设备的折射率分布,我们能够在QD介质中很好地限制波导模式,即使在超薄(约三个QD单层)有源层的情况下,也可以演示低阈值激光发射。这些器件在电泵浦下还具有很强的电致发光(EL)性能。进行的研究表明,已证明的双功能(激光/ EL)结构代表了实现胶体QD激光二极管的有前途的设备平台。
  • 【基于双硫th封端的ZnS量子点的灵敏荧光探针,用于生物样品中槲皮素的测定。】 复制标题 收藏 收藏
    DOI:10.1002/bio.3903 复制DOI
    作者列表:Sadeghi S,Hosseinpour-Zaryabi M
    BACKGROUND & AIMS: :A simple turn on/off fluorescence approach based on dithizone-capped ZnS quantum dots (ZnS@DZ QDs) with the help of lead ions as a fluorescent probe for the quantitative determination of quercetin is reported. The interaction of lead ions with dithizone led to the formation of a rigid structure on the surface of ZnS@DZ QDs and turned on the fluorescence intensity of the QDs. After addition of quercetin to this probe and interaction with lead ions, the fluorescence emission turned off. Concerning the quenching fluorescence intensity of ZnS@DZ QDs/Pb2+ QDs probe induced by the target, under the optimum conditions, the probe enabled detection of quercetin in the concentration range from 0.54 μM to 21.7 μM with a correlation coefficient of 0.993 and detection limit of 0.25 μM. The present probe was applied successfully to the determine quercetin as a nutritional biomarker in human serum and 24-h urine samples.
    背景与目标: :报道了一种基于双硫zone封端的ZnS量子点(ZnS @ DZ QDs)的简单打开/关闭荧光方法,该方法借助铅离子作为荧光探针来定量测定槲皮素。铅离子与双硫zone的相互作用导致在ZnS @ DZ量子点表面形成刚性结构,并开启了量子点的荧光强度。向该探针添加槲皮素并与铅离子相互作用后,荧光发射关闭。关于目标诱导的ZnS @ DZ QDs / Pb2 QDs探针的猝灭荧光强度,在最佳条件下,该探针能够检测浓度为0.54μM至21.7μM的槲皮素,相关系数为0.993,检测极限为0.25微米本探针已成功地应用于测定槲皮素作为人体血清和24小时尿液样品中的营养生物标志物。
  • 【具有离散调制的子载波连续可变量子密钥分配:数学模型和有限密钥分析。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-020-66948-0 复制DOI
    作者列表:Samsonov E,Goncharov R,Gaidash A,Kozubov A,Egorov V,Gleim A
    BACKGROUND & AIMS: :In this paper we report a continuous-variable quantum key distribution protocol using multimode coherent states generated on subcarrier frequencies of the optical spectrum. We propose a coherent detection scheme where power from a carrier wave is used as a local oscillator. We compose a mathematical model of the proposed scheme and perform its security analysis in the finite-size regime using fully quantum asymptotic equipartition property technique. We calculate a lower bound on the secret key rate for the system under the assumption that the quantum channel noise is negligible compared to detector dark counts, and an eavesdropper is restricted to collective attacks. Our calculation shows that the current realistic system implementation would allow distributing secret keys over channels with losses up to 9 dB.
    背景与目标: :在本文中,我们报告了一种连续可变量子密钥分配协议,该协议使用在光谱的子载波频率上生成的多模相干态。我们提出了一种相干检测方案,其中将来自载波的功率用作本地振荡器。我们组成了该方案的数学模型,并使用完全量子渐近等分性质技术在有限大小的方案中进行了安全性分析。我们假设量子信道噪声与检测器暗计数相比可忽略不计,并且窃听者仅限于集体攻击,从而计算出系统的秘密密钥率的下限。我们的计算表明,当前现实的系统实现方式将允许在损耗高达9 dB的信道上分配秘密密钥。
  • 【饱和潜水至2.5 MPa后,在减压期间间歇性地减少Po2时,肺功能无变化。】 复制标题 收藏 收藏
    DOI:10.1007/s00421-006-0276-8 复制DOI
    作者列表:Thorsen E,Segadal K,Stuhr LE,Troland K,Grønning M,Marstein S,Hope A
    BACKGROUND & AIMS: :Decompression stress and exposure to hyperoxia may cause a reduction in transfer factor of the lung for carbon monoxide and in maximal aerobic capacity after deep saturation dives. In this study lung function and exercise capacity were assessed before and after a helium-oxygen saturation dive to a pressure of 2.5 MPa where the decompression rate was reduced compared with previous deep dives, and the hyperoxic exposure was reduced by administering oxygen intermittently at pressures of 50 and 30 kPa during decompression. Eight experienced divers of median age 41 years (range 29-48) participated in the dive. The incidence of venous gas microemboli was low compared with previous deep dives. Except for one subject having treatment for decompression sickness, no changes in lung function or angiotensin converting enzyme, a marker of pulmonary endothelial cell damage, were demonstrated. The modified diving procedures with respect to decompression rate and hyperoxic exposure may have contributed to the lack of changes in lung function in this dive compared with previous deep saturation dives.
    背景与目标: :减压应力和高氧暴露可能导致一氧化碳的肺转移因子减少,并导致深度饱和潜水后最大有氧运动能力降低。在这项研究中,在氦氧饱和度潜水至2.5 MPa的压力之前和之后评估了肺功能和运动能力,与以前的深潜相比,减压率降低了,而在200℃的压力下间歇地给氧减少了高氧暴露减压期间为50和30 kPa。八名经验丰富的潜水员,中位数年龄为41岁(29-48岁),参加了此次潜水。与以前的深潜相比,静脉气体微栓塞的发生率低。除一名接受减压病治疗的受试者外,未证明肺功能或血管紧张素转换酶(肺内皮细胞损伤的标志物)发生变化。与以前的深度饱和潜水相比,在减压和高氧暴露方面经过改进的潜水程序可能导致该肺功能缺乏变化。
  • 【对行为改变的混乱看法:促进健康的巨大飞跃。】 复制标题 收藏 收藏
    DOI:10.1186/1479-5868-3-25 复制DOI
    作者列表:Resnicow K,Vaughan R
    BACKGROUND & AIMS: BACKGROUND:The study of health behavior change, including nutrition and physical activity behaviors, has been rooted in a cognitive-rational paradigm. Change is conceptualized as a linear, deterministic process where individuals weigh pros and cons, and at the point at which the benefits outweigh the cost change occurs. Consistent with this paradigm, the associated statistical models have almost exclusively assumed a linear relationship between psychosocial predictors and behavior. Such a perspective however, fails to account for non-linear, quantum influences on human thought and action. Consider why after years of false starts and failed attempts, a person succeeds at increasing their physical activity, eating healthier or losing weight. Or, why after years of success a person relapses. This paper discusses a competing view of health behavior change that was presented at the 2006 annual ISBNPA meeting in Boston. DISCUSSION:Rather than viewing behavior change from a linear perspective it can be viewed as a quantum event that can be understood through the lens of Chaos Theory and Complex Dynamic Systems. Key principles of Chaos Theory and Complex Dynamic Systems relevant to understanding health behavior change include: 1) Chaotic systems can be mathematically modeled but are nearly impossible to predict; 2) Chaotic systems are sensitive to initial conditions; 3) Complex Systems involve multiple component parts that interact in a nonlinear fashion; and 4) The results of Complex Systems are often greater than the sum of their parts. Accordingly, small changes in knowledge, attitude, efficacy, etc may dramatically alter motivation and behavioral outcomes. And the interaction of such variables can yield almost infinite potential patterns of motivation and behavior change. In the linear paradigm unaccounted for variance is generally relegated to the catch all "error" term, when in fact such "error" may represent the chaotic component of the process. The linear and chaotic paradigms are however, not mutually exclusive, as behavior change may include both chaotic and cognitive processes. Studies of addiction suggest that many decisions to change are quantum rather than planned events; motivation arrives as opposed to being planned. Moreover, changes made through quantum processes appear more enduring than those that involve more rational, planned processes. How such processes may apply to nutrition and physical activity behavior and related interventions merits examination.
    背景与目标: 背景:对健康行为变化(包括营养和身体活动行为)的研究已扎根于认知理性范式。变革在概念上是线性的,确定性的过程,在此过程中,个人权衡利弊,并在收益大于成本的情况下发生变化。与此范例相一致,相关的统计模型几乎完全假定了心理社会预测因素与行为之间的线性关系。然而,这样的观点未能说明非线性的,量子的对人类思想和行为的影响。考虑为什么在经过多年的错误开始和失败尝试之后,一个人成功地增加了自己的体育锻炼,饮食健康或减肥。或者,为什么一个人在多年成功之后会复发。本文讨论了在波士顿举行的2006年度ISBNPA年会上提出的有关健康行为改变的竞争观点。
    讨论:不是从线性的角度观察行为的变化,它可以被看作是一个量子事件,可以通过混沌理论和复杂动力系统的角度来理解。与理解健康行为变化相关的混沌理论和复杂动力系统的关键原理包括:1)混沌系统可以进行数学建模,但几乎无法预测; 2)混沌系统对初始条件敏感; 3)复杂系统包含以非线性方式交互的多个组成部分;和4)复杂系统的结果通常大于其各个部分的总和。因此,知识,态度,功效等方面的细微变化可能会极大地改变动机和行为结果。这些变量的相互作用可以产生几乎无限的潜在动机和行为改变模式。在线性范式中,未解释方差通常归结为“所有错误”一词,而实际上这种“错误”可能代表过程的混乱成分。然而,线性和混沌范式并不是相互排斥的,因为行为改变可能包括混沌和认知过程。对成瘾的研究表明,许多改变决定是量子的,而不是计划的事件。动机到来而不是被计划。而且,通过量子过程进行的变化看起来比那些涉及更合理,计划的过程的变化更持久。这些过程如何适用于营养和身体活动行为以及相关干预措施,值得研究。
  • 【能量转移对具有CdSe / ZnS量子点的表面钝化钙钛矿薄膜光学性能的影响。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-019-54860-1 复制DOI
    作者列表:Cho IW,Ryu MY
    BACKGROUND & AIMS: :Surface passivation is an effective method to protect the surfaces and improve the luminescence properties of perovskite (PS) films. CdSe/ZnS core-shell quantum dots (QDs) have been employed for surface passivation of PS films because of their size-dependent tunable bandgaps. Herein, the energy transfer (ET) behavior of CH3NH3PbI2Br PS films covered with CdSe/ZnS QDs (QD/PS hybrid structures) is characterized by using photoluminescence (PL) and time-resolved PL spectroscopy. The PL decay time and the integrated PL intensity of the QD/PS hybrid structure increase compared with those of the bare PS films, owing to ET from the QDs to the PS and reduced charge traps. The ET efficiency increases from ~7% to 63% for the QD/PS hybrid structure when the core diameter of the QDs decreases from 6.5 to 2.7 nm, respectively. This can be explained by the charge transfer rate enhancement due to the control of energy level alignment of QDs. These results allow us to understand fundamental mechanisms such as ET from QDs to PS films as a function of the size of the QD.
    背景与目标: :表面钝化是保护表面并改善钙钛矿(PS)膜发光性能的有效方法。 CdSe / ZnS核-壳量子点(QDs)已被用于PS膜的表面钝化,因为它们的尺寸取决于可调带隙。在此,通过使用光致发光(PL)和时间分辨PL光谱来表征覆盖有CdSe / ZnS QDs(QD / PS杂化结构)的CH3NH3PbI2Br PS薄膜的能量转移(ET)行为。与裸PS膜相比,QD / PS杂化结构的PL衰减时间和积分PL强度增加,这是由于从QD到PS的ET以及电荷陷阱的减少。当QDs的芯径分别从6.5nm减小到2.7nm时,QD / PS混合结构的ET效率从7%增至63%。这可以通过控制QD的能级对齐来提高电荷传输速率来解释。这些结果使我们能够了解基本机制,例如从QD到PS薄膜的ET,它们是QD尺寸的函数。
  • 【色素-蛋白质复合物中长寿命量子相干性和激发动力学的起源。】 复制标题 收藏 收藏
    DOI:10.1038/srep37629 复制DOI
    作者列表:Zhang Z,Wang J
    BACKGROUND & AIMS: :We explore the mechanism for the long-lived quantum coherence by considering the discrete phonon modes: these vibrational modes effectively weaken the exciton-environment interaction, due to the new composite (polaron) formed by excitons and vibrons. This subsequently demonstrates the role of vibrational coherence which greatly contributes to long-lived feature of the excitonic coherence that has been observed in femtosecond experiments. The estimation of the timescale of coherence elongated by vibrational modes is given in an analytical manner. To test the validity of our theory, we study the pigment-protein complex in detail by exploring the energy transfer and coherence dynamics. The ground-state vibrational coherence generated by incoherent radiations is shown to be long-survived and is demonstrated to be significant in promoting the excitation energy transfer. This is attributed to the nonequilibriumness of the system caused by the detailed-balance-breaking, which funnels the downhill migration of excitons.
    背景与目标: :我们通过考虑离散声子模式来探索长寿命量子相干的机制:由于激子和振动子形成了新的复合物(极化子),这些振动模式有效地削弱了激子与环境的相互作用。随后证明了振动相干的作用,这极大地促进了在飞秒实验中观察到的激子相干的长寿命特征。通过分析方式给出了由振动模态拉长的相干时间尺度的估计。为了验证我们理论的正确性,我们通过探索能量转移和相干动力学来详细研究色素-蛋白质复合物。由非相干辐射产生的基态振动相干被证明可以长期存在,并被证明在促进激发能传递方面具有重要意义。这归因于详细平衡的破坏导致系统的不平衡,这使激子的下坡迁移成为可能。
  • 【在具有量子点接触的双层纳米线中,子带间自旋轨道耦合产生的自旋滤波效应。】 复制标题 收藏 收藏
    DOI:10.1038/srep45346 复制DOI
    作者列表:Wójcik P,Adamowski J
    BACKGROUND & AIMS: :The spin filtering effect in the bilayer nanowire with quantum point contact is investigated theoretically. We demonstrate the new mechanism of the spin filtering based on the lateral inter-subband spin-orbit coupling, which for the bilayer nanowires has been reported to be strong. The proposed spin filtering effect is explained as the joint effect of the Landau-Zener intersubband transitions caused by the hybridization of states with opposite spin (due to the lateral Rashba SO interaction) and the confinement of carriers in the quantum point contact region.
    背景与目标: :从理论上研究了量子点接触双层纳米线中的自旋滤波效应。我们展示了基于横向子带间自旋轨道耦合的自旋滤波的新机制,据报道,该机制对于双层纳米线很强。提出的自旋滤波效应被解释为Landau-Zener子带间跃迁的联合效应,这是由于具有相反自旋的态(由于横向Rashba SO相互作用)和载流子限制在量子点接触区域中所引起的。
  • 【固有的无限维量子相关性。】 复制标题 收藏 收藏
    DOI:10.1038/s41467-020-17077-9 复制DOI
    作者列表:Coladangelo A,Stark J
    BACKGROUND & AIMS: :Bell's theorem, a landmark result in the foundations of physics, establishes that quantum mechanics is a non-local theory. It asserts, in particular, that two spatially separated, but entangled, quantum systems can be correlated in a way that cannot be mimicked by classical systems. A direct operational consequence of Bell's theorem is the existence of statistical tests which can detect the presence of entanglement. Remarkably, certain correlations not only witness entanglement, but they give quantitative bounds on the minimum dimension of quantum systems attaining them. In this work, we show that there exists a correlation which is not attainable by quantum systems of any arbitrary finite dimension, but is attained exclusively by infinite-dimensional quantum systems (such as infinite-level systems arising from quantum harmonic oscillators). This answers the long-standing open question about the existence of a finite correlation witnessing infinite entanglement.
    背景与目标: :贝尔定理是物理学基础上的一个里程碑式的结果,它确立了量子力学是一种非局部理论。它特别指出,两个空间上分离但纠缠的量子系统可以以经典系统无法模仿的方式相互关联。贝尔定理的直接运算结果是统计检验的存在,该检验可以检测到纠缠的存在。值得注意的是,某些关联不仅证明了纠缠,而且还给出了达到它们的量子系统的最小维度的定量界限。在这项工作中,我们表明存在一个相关性,这是任何任意有限维的量子系统都无法实现的,而只能通过无限维的量子系统(例如由量子谐波振荡器产生的无限级系统)才能实现。这回答了关于存在无限纠缠的有限相关性的长期存在的开放性问题。
  • 【钙钛矿中量子点固体的场发射。】 复制标题 收藏 收藏
    DOI:10.1038/ncomms14757 复制DOI
    作者列表:García de Arquer FP,Gong X,Sabatini RP,Liu M,Kim GH,Sutherland BR,Voznyy O,Xu J,Pang Y,Hoogland S,Sinton D,Sargent E
    BACKGROUND & AIMS: :Quantum dot and well architectures are attractive for infrared optoelectronics, and have led to the realization of compelling light sensors. However, they require well-defined passivated interfaces and rapid charge transport, and this has restricted their efficient implementation to costly vacuum-epitaxially grown semiconductors. Here we report solution-processed, sensitive infrared field-emission photodetectors. Using quantum-dots-in-perovskite, we demonstrate the extraction of photocarriers via field emission, followed by the recirculation of photogenerated carriers. We use in operando ultrafast transient spectroscopy to sense bias-dependent photoemission and recapture in field-emission devices. The resultant photodiodes exploit the superior electronic transport properties of organometal halide perovskites, the quantum-size-tuned absorption of the colloidal quantum dots and their matched interface. These field-emission quantum-dot-in-perovskite photodiodes extend the perovskite response into the short-wavelength infrared and achieve measured specific detectivities that exceed 1012 Jones. The results pave the way towards novel functional photonic devices with applications in photovoltaics and light emission.
    背景与目标: :量子点和阱结构对红外光电器件很有吸引力,并导致了引人注目的光传感器的实现。然而,它们需要良好定义的钝化界面和快速的电荷传输,这将它们的有效实施限制在昂贵的真空外延生长的半导体上。在这里,我们报告解决方案处理,敏感的红外场发射光电探测器。我们使用钙钛矿中的量子点,通过场发射演示了光载流子的提取,然后是光生载流子的再循环。我们在操作超快瞬态光谱学中使用以感测偏置相关的光发射和场发射器件中的捕获。所得的光电二极管利用了有机金属卤化物钙钛矿的优异电子传输性能,胶体量子点的量子尺寸调谐吸收及其匹配的界面。这些场发射型钙钛矿中的量子点光电二极管将钙钛矿响应扩展到短波长红外中,并实现了超过1012 Jones的测量比探测率。结果为在光伏和光发射中应用的新型功能性光子器件铺平了道路。
  • 【半导体中多体过程和基本量子力学现象的超快动力学。】 复制标题 收藏 收藏
    DOI:10.1073/pnas.97.6.2437 复制DOI
    作者列表:Chemla DS,Shah J
    BACKGROUND & AIMS: :The large dielectric constant and small effective mass in a semiconductor allows a description of its electronic states in terms of envelope wavefunctions whose energy, time, and length scales are mesoscopic, i.e., halfway between those of atomic and those of condensed matter systems. This property makes it possible to demonstrate and investigate many quantum mechanical, many-body, and quantum kinetic phenomena with tabletop experiments that would be nearly impossible in other systems. This, along with the ability to custom-design semiconductor nanostructures, makes semiconductors an ideal laboratory for experimental investigations. We present an overview of some of the most exciting results obtained in semiconductors in recent years using the technique of ultrafast nonlinear optical spectrocopy. These results show that Coulomb correlation plays a major role in semiconductors and makes them behave more like a strongly interacting system than like an atomic system. The results provide insights into the physics of strongly interacting systems that are relevant to other condensed matter systems, but not easily accessible in other materials.
    背景与目标: 半导体中的大介电常数和小的有效质量可以用包络波函数描述其电子状态,包络波函数的能量,时间和长度尺度是介观的,即介于原子和凝聚态系统之间。这种特性使通过桌面实验来证明和研究许多量子力学,多体和量子动力学现象成为可能,而在其他系统中这几乎是不可能的。加上定制设计半导体纳米结构的能力,使得半导体成为进行实验研究的理想实验室。我们概述了近年来使用超快速非线性光学光谱技术在半导体领域获得的最令人兴奋的结果。这些结果表明,库仑相关性在半导体中起主要作用,并使它们的行为更像是一个强相互作用的系统,而不是原子系统。结果提供了对与其他凝聚态系统相关但在其他材料中不易访问的强相互作用系统的物理学的见解。
  • 【印度德里实习生中关于结核病和斑点的知识,态度和做法。】 复制标题 收藏 收藏
    DOI:08.2007/JCPSP.457461 复制DOI
    作者列表:Rajpal S,Mittal A,Dhingra VK,Malhotra R,Gupta R,Malhotra C,Taneja DK
    BACKGROUND & AIMS: OBJECTIVE:To assess the knowledge, attitude and practices regarding tuberculosis (TB) and DOTS among young medical graduates (interns). DESIGN:Cross-sectional study. PLACE AND DURATION OF STUDY:Lady Hardinge Medical College and Maulana Azad Medical College, New Delhi, India, during November and December 2002, simultaneously. SUBJECTS AND METHODS:A pre-tested semi-structured questionnaire consisting of 30 items was administered to the young medical graduates/interns posted in different departments. The questions covered mode of transmission, symptoms of pulmonary TB, investigations, short course chemotherapy including DOTS as well as conventional anti-tubercular treatment, special situations, health education and chemoprophylaxis. RESULTS:A total of 287 interns were surveyed. Majority of the study subjects (92.7%) ranked DOTS strategy as more successful for treating tuberculosis in comparison to self-administered therapy. However, a mere 4.2% study subjects were aware of all modes of transmission. One hundred and eighty-nine (65.9%) correctly chose sputum examination for acid fast bacilli as the single most confirmatory test for diagnosing pulmonary TB. The rest either gave incorrect responses (including ELISA-17.0%, PCR-9.8%, X-ray chest-4.2%, ESR-1.7%) or did not respond (1.4%). Only 2.1% marked pyrazinamide and rifampicin as the agents to be avoided in patients with liver disease. One hundred and forty-one different treatment regimens were mentioned in the responses received and of those only 11(7.8%) were scientifically acceptable. CONCLUSION:TB is a major health problem in South-East Asian countries. There is a need for appropriate changes to be made in the undergraduate medical teaching/training curriculum in the concerned countries with regard to TB.
    背景与目标: 目的:评估年轻医学毕业生(实习生)关于结核病(TB)和DOTS的知识,态度和做法。
    设计:横断面研究。
    研究的地点和时间:2002年11月至2002年12月,印度新德里哈丁夫人医学院和毛拉纳·阿扎德医学院。
    研究对象和方法:对张贴在不同部门的年轻医学毕业生/实习生进行了预先测试的,由30个项目组成的半结构化问卷。问题包括传播方式,肺结核的症状,研究,包括DOTS在内的短期化疗以及常规抗结核治疗,特殊情况,健康教育和化学预防。
    结果:共对287名实习生进行了调查。大多数研究对象(92.7%)将DOTS策略评为比自我治疗更成功的治疗结核病。但是,仅有4.2%的研究对象知道所有传播方式。一百八十九(65.9%)正确地选择了痰液检查来检查耐酸性细菌,这是诊断肺结核的最有力的方法。其余的患者反应不正确(包括ELISA-17.0%,PCR-9.8%,X射线胸腔仪4.2%,ESR-1.7%)或没有反应(1.4%)。仅有2.1%的患者将吡嗪酰胺和利福平标记为肝病患者应避免的药物。在收到的答复中提到了一百四十一种不同的治疗方案,其中只有11种(7.8%)在科学上是可以接受的。
    结论:结核病是东南亚国家的主要健康问题。在有关结核病的有关国家中,有必要对本科医学教学/培训课程进行适当的修改。
  • 【以抗原和抗体的免疫复合物为桥的两个量子点之间的荧光共振能量转移。】 复制标题 收藏 收藏
    DOI:10.1002/bio.927 复制DOI
    作者列表:Li Y,Ma Q,Wang X,Su X
    BACKGROUND & AIMS: :In this study, 573 nm quantum dots (QDs)-rabbit IgG-goat anti-rabbit IgG-638 nm QDs immunocomplexes were prepared, utilizing antigen-antibody interaction. 573 nm-emitting QDs were conjugated to antigen (rabbit IgG) and 638 nm-emitting QDs were conjugated to antibody (goat anti-rabbit IgG) via electrostatic/hydrophilic self-assembly, respectively. The mutual affinity of the antigen and antibody brought two kinds of QDs close enough to result in fluorescence resonance energy transfer (FRET) between them; the luminescence emission of 573 nm QDs was quenched, while that of 638 nm QDs was enhanced. The luminescence emission of 573 nm QDs could be recovered when the immunocomplexes were exposed to the unlabelled rabbit IgG antigen. The FRET efficiency (E) and the distance between the donor and the acceptor were calculated.
    背景与目标: :在这项研究中,利用抗原-抗体相互作用制备了573 nm量子点(QDs)-兔IgG-山羊抗兔IgG-638 nm QDs免疫复合物。分别通过静电/亲水自组装将573 nm发射的QD与抗原(兔IgG)偶联,将638 nm发射的QD与抗体(山羊抗兔IgG)偶联。抗原和抗体的相互亲和力使两种QD足够接近,从而导致它们之间的荧光共振能量转移(FRET)。 573 nm QD的发光被淬灭,而638 nm QD的发光被增强。当免疫复合物暴露于未标记的兔IgG抗原时,可以回收573 nm QD的发光。计算出FRET效率(E)和供体与受体之间的距离。
  • 【针对一般攻击的连续变量独立于源设备的量子密钥分配。】 复制标题 收藏 收藏
    DOI:10.1038/s41598-020-63024-5 复制DOI
    作者列表:Zhang Y,Chen Z,Weedbrook C,Yu S,Guo H
    BACKGROUND & AIMS: :The continuous-variable quantum key distribution with entanglement in the middle, a semi-device-independent protocol, places the source at the untrusted third party between Alice and Bob, and thus has the advantage of high levels of security with the purpose of eliminating the assumptions about the source device. However, previous works considered the collective-attack analysis, which inevitably assumes that the states of the source has an identical and independently distributed (i.i.d) structure, and limits the application of the protocol. To solve this problem, we modify the original protocol by exploiting an energy test to monitor the potential high energy attacks an adversary may use. Our analysis removes the assumptions of the light source and the modified protocol can therefore be called source-device-independent protocol. Moreover, we analyze the security of the continuous-variable source-device-independent quantum key distribution protocol with a homodyne-homodyne structure against general coherent attacks by adapting a state-independent entropic uncertainty relation. The simulation results indicate that, in the universal composable security framework, the protocol can still achieve high key rates against coherent attacks under the condition of achievable block lengths.
    背景与目标: :中间纠缠的连续变量量子密钥分布(一种与半设备无关的协议)将源放置在Alice和Bob之间的不受信任的第三方处,因此具有高安全级别的优点,从而消除了关于源设备的假设。但是,先前的工作考虑了集体攻击分析,该分析不可避免地假设源的状态具有相同且独立分布的(i.i.d)结构,并限制了协议的应用。为了解决此问题,我们通过利用能量测试来监视对手可能使用的潜在高能量攻击,来修改原始协议。我们的分析消除了光源的假设,因此修改后的协议可以称为独立于源设备的协议。此外,我们通过适应独立于状态的熵不确定性关系,分析了具有零差-homodyne结构的连续变量与源设备无关的量子密钥分发协议针对一般相干攻击的安全性。仿真结果表明,在通用的可组合安全框架下,该协议在块长度可达到的情况下,仍然可以实现较高的密钥速率来抵御相干攻击。
  • 【电荷对KcsA通道门控的量子力学计算。】 复制标题 收藏 收藏
    DOI:10.1016/j.bbamem.2007.01.021 复制DOI
    作者列表:Kariev AM,Znamenskiy VS,Green ME
    BACKGROUND & AIMS: :A series of ab initio (density functional) calculations were carried out on side chains of a set of amino acids, plus water, from the (intracellular) gating region of the KcsA K(+) channel. Their atomic coordinates, except hydrogen, are known from X-ray structures [D.A. Doyle, J.M. Cabral, R.A. Pfuetzner, A. Kuo, J.M. Gulbis, S.L. Cohen, B.T. Chait, R. MacKinnon, The structure of the potassium channel: molecular basis of K(+) conduction and selectivity, Science 280 (1998) 69-77; R. MacKinnon, S.L. Cohen, A. Kuo, A. Lee, B.T. Chait, Structural conservation in prokaryotic and eukaryotic potassium channels, Science 280 (1998) 106-109; Y. Jiang, A. Lee, J. Chen, M. Cadene, B.T. Chait, R. MacKinnon, The open pore conformation of potassium channels. Nature 417 (2001) 523-526], as are the coordinates of some water oxygen atoms. The 1k4c structure is used for the starting coordinates. Quantum mechanical optimization, in spite of the starting configuration, places the atoms in positions much closer to the 1j95, more tightly closed, configuration. This state shows four water molecules forming a "basket" under the Q119 side chains, blocking the channel. When a hydrated K(+) approaches this "basket", the optimized system shows a strong set of hydrogen bonds with the K(+) at defined positions, preventing further approach of the K(+) to the basket. This optimized structure with hydrated K(+) added shows an ice-like 12 molecule nanocrystal of water. If the water molecules exchange, unless they do it as a group, the channel will remain blocked. The "basket" itself appears to be very stable, although it is possible that the K(+) with its hydrating water molecules may be more mobile, capable of withdrawing from the gate. It is also not surprising that water essentially freezes, or forms a kind of glue, in a nanometer space; this agrees with experimental results on a rather different, but similarly sized (nm dimensions) system [K.B. Jinesh, J.W.M. Frenken, Capillary condensation in atomic scale friction: how water acts like a glue, Phys. Rev. Lett. 96 (2006) 166103/1-4]. It also agrees qualitatively with simulations on channels [A. Anishkin, S. Sukharev, Water dynamics and dewetting transitions in the small mechanosensitive channel MscS, Biophys. J. 86 (2004) 2883-2895; O. Beckstein, M.S.P. Sansom, Liquid-vapor oscillations of water in hydrophobic nanopores, Proc. Natl Acad. Sci. U. S. A. 100 (2003) 7063-7068] and on featureless channel-like systems [J. Lu, M.E. Green, Simulation of water in a pore with charges: application to a gating mechanism for ion channels, Prog. Colloid Polym. Sci. 103 (1997) 121-129], in that it forms a boundary on water that is not obvious from the liquid state. The idea that a structure is stable, even if individual molecules exchange, is well known, for example from the hydration shell of ions. We show that when charges are added in the form of protons to the domains (one proton per domain), the optimized structure is open. No stable water hydrogen bonds hold it together; an opening of 11.0 A appears, measured diagonally between non-neighboring domains as glutamine 119 carbonyl O-O distance. This is comparable to the opening in the MthK potassium channel structure that is generally agreed to be open. The appearance of the opening is in rather good agreement with that found by Perozo and coworkers. In contrast, in the uncharged structure this diagonal distance is 6.5 A, and the water "basket" constricts the uncharged opening still further, with the ice-like structure that couples the K(+) ion to the gating region freezing the entrance to the channel. Comparison with our earlier model for voltage gated channels suggests that a similar mechanism may apply in those channels.
    背景与目标: :从KcsA K()通道的(细胞内)门控区域对一组氨基酸加上水的侧链进行了一系列从头算(密度函数)计算。从氢射线结构可以知道它们的原子坐标(氢除外)[D.A。 Doyle,J.M. Cabral,R.A. Pfuetzner,A.Kou,J.M. Gulbis,S.L.英国科恩(Cohen) Chait,R.MacKinnon,钾通道的结构:K()传导和选择性的分子基础,Science 280(1998)69-77。麦金农(S.L.) Cohen,A.Kou,A.Lee,B.T. Chait,原核和真核钾通道中的结构保守性,Science 280(1998)106-109。江,李安,陈洁,M.Cadene,B.T。 Chait,R. MacKinnon,钾通道的开孔构象。 Nature 417(2001)523-526],以及一些水氧原子的坐标。 1k4c结构用于起始坐标。尽管采用了初始配置,但量子力学优化仍将原子放置在更接近1j95(更紧密闭合)的位置。此状态显示四个水分子在Q119侧链下方形成“篮子”,从而阻塞了通道。当水合的K()接近此“篮子”时,优化的系统会在K()的指定位置显示一组牢固的氢键,从而防止K()进一步接近篮子。添加水合K()的这种优化结构显示出水的冰状12分子纳米晶体。如果水分子交换,除非它们作为一个整体进行交换,否则通道将保持阻塞状态。 “篮子”本身似乎非常稳定,尽管带有水化水分子的K()可能更易移动,能够从闸门中撤出。同样,毫不奇怪的是,水在纳米空间中基本上会冻结或形成一种胶。这与在一个完全不同但大小相似(纳米尺寸)的系统上的实验结果相吻合[K.B. Jinesh,J.W.M. Frenken,毛细管缩合在原子尺度上的摩擦:水如何像胶一样起作用,物理学。莱特牧师96(2006)166103 / 1-4]。它在质量上也与通道模拟[A. Anishkin,S。Sukharev,小型机械敏感通道MscS中的水动力学和去湿转换,Biophys。 J.86(2004)2883-2895; O.贝克斯坦(M.S.P.) Sansom,疏水纳米孔中水的液-汽振荡,Proc.Natl.Acad.Sci.USA,88:1593-2404。纳特·阿卡德(Natl Acad)。科学U. S. A. 100(2003)7063-7068]和无特征的类通道系统[J. Lu,M.E. Green,带电荷的孔中水的模拟:应用于离子通道的门控机制,Prog。胶体Polym。科学103(1997)121-129],因为它在水上形成了边界,从液体状态看,边界并不明显。即使单个分子交换,结构也是稳定的想法是众所周知的,例如从离子的水合壳中。我们显示出,当电荷以质子的形式添加到域中(每个域一个质子)时,优化的结构是开放的。没有稳定的水氢键将其结合在一起。出现11.0 A的开口,对角线在非相邻域之间以谷氨酰胺119羰基O-O距离进行测量。这相当于通常被认为是开放的MthK钾通道结构中的开放。开口的外观与Perozo及其同事发现的外观非常吻合。相反,在不带电的结构中,对角线距离为6.5 A,水“篮”进一步限制了不带电的开口,而冰状结构将K()离子耦合到门控区域,从而冻结了通道​​的入口。 。与我们先前的电压门控通道模型进行比较表明,类似的机制可能适用于这些通道。

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