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Electrostatic Mechanism for Depolymerization-Based Poleward Force Generation at Kinetochores 基于解聚的着丝点极性力产生的静电机制
Pub Date : 2019-05-20 DOI: 10.4236/OJBIPHY.2019.93014
L. J. Gagliardi, D. Shain
Experiments implicating bound volume positive charge at kinetochores interacting with negative charge at microtubule free ends have prompted our calculation of the force at kinetochores for chromosome poleward motility during mitosis. We present here a corroborating force calculation between positively charged Hec1 tails in kinetochores and negatively charged C-termini at microtubule free ends. Based on experimentally-known charge magnitudes on Hec1 tails and C-termini at microtubule free ends, an ab initio calculation of poleward (tension) force per microtubule that falls within the experimental range is demonstrated. Due to the locations of C-termini charges on concave sides of splaying microtubules, this attractive force between subsets of low curvature splaying microtubule protofilaments C-termini eventually fails for subsets of protofilaments with more pronounced curvature, thus generating poleward force as microtubules depolymerize in a dynamic coupling, as observed experimentally. The mechanism by which kinetochores establish and maintain a dynamic coupling to microtubules for force production during the complex motions of mitosis remains elusive, and force generation at kinetochores has emerged as a signature problem in chromosome motility. In agreement with experiment, two separate calculations show that attractive electrostatic interactions over nanometer distances account for poleward chromosome forces at kinetochores.
实验表明,着丝点上的结合体积正电荷与微管自由端的负电荷相互作用,促使我们计算有丝分裂过程中着丝点上的力对染色体极性运动的影响。我们在此提出了一个确证力计算在带正电的Hec1尾部和带负电的c末端在微管自由端。基于实验已知的Hec1尾部和微管自由端c末端的电荷量,证明了在实验范围内的每个微管的极性(张力)力的从头计算。实验观察到,由于c端电荷位于微管的凹侧,低曲率的微管原丝亚群之间的吸引力c端最终对曲率更大的微管原丝亚群失效,从而在微管动态耦合解聚过程中产生极性力。在有丝分裂的复杂运动中,着丝点如何建立并维持与微管的动态耦合以产生力的机制尚不清楚,而着丝点的力产生已成为染色体运动中的一个标志性问题。与实验一致,两个独立的计算表明,纳米距离上的吸引静电相互作用解释了着丝点上的染色体极性力。
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引用次数: 0
DNA Sequencing: Current State and Prospects of Development DNA测序:现状与发展前景
Pub Date : 2019-05-20 DOI: 10.4236/ojbiphy.2019.93013
L. Gasparyan, I. Mazo, V. Simonyan, F. Gasparyan
In this review, we collected and classified the stages of development of DNA sequencing methods and described its peculiarities. We pay attention mostly on solid-stead nanopore sequencing methods. Detailed discussion of the peculiarity and feasibility of the electrical methods of DNA sequencing is discussed. The detail analyses of the literature data, some critical considerations and the potential ways of optimization of DNA nanopore sequencing were presented.
在这篇综述中,我们收集和分类了DNA测序方法的发展阶段,并描述了其特点。我们主要关注固体纳米孔测序方法。详细讨论了DNA电测序方法的特点和可行性。对文献数据进行了详细的分析,并提出了一些关键问题和优化DNA纳米孔测序的潜在途径。
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引用次数: 7
Non-Invasive Vibration-Stress of the Cirrhotic Liver of Patients Waiting for Transplantation Induces of Circulating CD133+ Stem Lymphocytes Committed Phenotypically toward the Liver 等待移植的肝硬化患者肝脏的无创振动应激诱导循环CD133+干细胞表型向肝转移
Pub Date : 2019-05-20 DOI: 10.4236/OJBIPHY.2019.93012
A. N. Shoutko, O. Gerasimova, V. Fedorov, F. K. Zherebtsov
Background: Numerous studies of tissues’ regeneration have confessed the recovery of damaged liver by hematopoietic stem cells. The cells act not only by cell replacement in the target organ but also by delivering trophic factors that support endogenous liver regeneration. A little is known of how organ-derived signals recruit such committed cells into circulation. Objective: We investigated the roles of noninvasive mechanical percutaneous stress of cirrhotic human liver in numbers fluctuation of trophic, liver-specific alpha-fetoprotein-positive fraction of CD133-positive hematopoietic stem cells in lymphocytes of patients waiting for liver transplantation. Methods: To promote in blood the number of the alpha-fetoprotein-positive fraction of CD133-positive hematopoietic stem cells, committed to liver’ tissue, we activated mechanically the cirrhotic liver of patient by transcutaneous micro vibration received from skin-contacted electro-magnetic vibraphones generated mechanical pulses with amplitude 10 μm and smoothly changing frequency from 0.03 kHz to 18 kHz and back forth during one cycle duration 1 minute. The number of the alpha-fetoprotein-positive fraction of CD133-positive hematopoietic stem cells in lymphocytes of potential recipients was controlled by flow cytometry before and during daily sonication of skin area, which corresponds to liver projection on it. The 15 minutes cyclic sonication of the liver area performed daily for three weeks. Results: The sonication increased significantly averaged number of liver-specific alpha-fetoprotein-positive CD133-positive blood lymphocytes in 2 - 3 times compared to a base lane. The second similar sonication, the same zone after three weeks break showed differences with baseline, but it was statistically insignificant. The result was specifically related to the liver as it showed the control sonication of the backbone’s projection on the skin of a separate group of patients with cirrhotic liver from the waiting list. Conclusion: The stem cells committed to the liver recruit from the bone marrow into circulation, when organ mechanically stresses and secretes specific humoral signals to provoke of lymphopoiesis on host liver repair.
背景:大量关于组织再生的研究表明,造血干细胞可以修复受损的肝脏。细胞不仅通过靶器官中的细胞置换发挥作用,还通过输送支持内源性肝脏再生的营养因子发挥作用。关于器官来源的信号是如何将这些承诺的细胞募集到循环中的,目前知之甚少。目的:探讨肝硬化患者肝脏无创机械经皮应力在等待肝移植患者淋巴细胞中CD133阳性造血干细胞的肝脏特异性甲胎蛋白阳性部分数量波动中的作用。方法:为了提高血中CD133阳性造血干细胞中甲胎蛋白阳性部分的数量,我们通过从皮肤接触的电磁振子接收经皮微振动来机械激活患者的肝硬化。电磁振子产生振幅为10μm、频率从0.03kHz平滑变化到18kHz的机械脉冲,并在一个周期内来回变化1分钟。在每天对皮肤区域进行超声处理之前和期间,通过流式细胞术控制潜在受体淋巴细胞中CD133阳性造血干细胞的甲胎蛋白阳性部分的数量,这与肝脏在皮肤区域上的投影相对应。每天对肝脏区域进行15分钟的循环超声处理,持续三周。结果:与基线相比,超声处理显著增加了肝特异性甲胎蛋白阳性CD133阳性血淋巴细胞的平均数量2-3倍。第二次类似的超声处理,在休息三周后的同一区域显示出与基线的差异,但在统计学上不显著。这一结果与肝脏特别相关,因为它显示了一组来自等待名单的肝硬化患者的脊椎投影在皮肤上的对照超声处理。结论:当器官机械应激并分泌特异性体液信号以刺激宿主肝脏修复中的淋巴生成时,肝脏干细胞从骨髓中募集到循环中。
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引用次数: 2
Evaluation of the Knowledge of CT Scan Prescribers on Patients’ Radioprotection in Senegal 塞内加尔CT扫描医生对患者放射防护知识的评估
Pub Date : 2019-05-20 DOI: 10.4236/OJBIPHY.2019.93015
S. M. Badiane, Pape Ibrahima Sane, C. Ndiaye, K. Gueye, O. Ndoye, K. M. Amoussou-Guénou, M. Mbodji
Medical imaging has enabled major improvements in the medical care of the patient. However, some of these tests have the disadvantage of using ionizing radiation at low doses. Although the CT scan is a powerful diagnostic tool, it remains a highly radiant imaging modality. In addition, the risk of radiation-induced cancer associated with low X-ray doses is established by the American Phase 2 study BEIR VII, and preventive measures require a good level of knowledge on radioprotection by imaging test prescribers. In our study, we evaluated the knowledge of CT scan prescribers in Senegal regarding patient radioprotection. These prescribers consisted of physicians and surgeons without distinction of specialty. Our objective was to have the required data for optimizing CT prescriptions in compliance with the principles of radioprotection. Our work focused on a descriptive analytical study of 107 doctors who prescribed CT scan in public health institutions in Senegal. Our results revealed poor knowledge of doctors prescribing CT scan on induced radio risks, even though the majority of them stated that they took those risks into account. Our data were not isolated, they were applicable to similar studies conducted outside Senegal. In summary, our study led on the one hand to recommendations on initial and continuing training and on the other hand on organizational and regulatory considerations.
医学成像使病人的医疗护理有了重大改进。然而,其中一些测试的缺点是使用低剂量的电离辐射。尽管CT扫描是一种强大的诊断工具,但它仍然是一种高度辐射的成像方式。此外,美国2期研究BEIR VII确定了与低X射线剂量相关的辐射诱发癌症的风险,预防措施需要成像测试处方医生具备良好的辐射防护知识。在我们的研究中,我们评估了塞内加尔CT扫描处方医生对患者辐射防护的了解。这些处方医生由医生和外科医生组成,没有专业区别。我们的目标是根据放射防护原则,获得优化CT处方所需的数据。我们的工作重点是对塞内加尔公共卫生机构107名开具CT扫描处方的医生进行描述性分析研究。我们的研究结果显示,尽管大多数医生表示他们已经考虑到了这些风险,但他们对医生开具的诱发放射性风险CT扫描处方知之甚少。我们的数据并非孤立的,它们适用于塞内加尔以外进行的类似研究。总之,我们的研究一方面提出了关于初始培训和继续培训的建议,另一方面也提出了关于组织和监管方面的考虑。
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引用次数: 0
Aging Leads to Over-Expression of Na+/K+ Pump Units in Liver and Na+/Ca2+ Exchangers in Brain Cortex 衰老导致肝脏中Na+/K+泵单位和脑皮质中Na+/Ca2+交换器的过度表达
Pub Date : 2019-05-20 DOI: 10.4236/OJBIPHY.2019.93016
A. Nikoghosyan, Armenuhi Heqimyan, S. Ayrapetyan
The metabolic controlling of tissue hydration is the fundamental parameter determining cell functional activity and its dysfunction is the common consequence of any cell pathology, including aging. The aim of the present study is to reveal the differences of age-dependent metabolic controlling of cell hydration of excitable tissue such as brain cortex and non-excitable tissues such as liver and spleen. For this purpose, the age-dependent sensitivity of cell hydration in excitable and non-excitablet issues is studied through depressing metabolic activity by cooling and its activation by supplying animals with distilled water, by inactivation of Na+/K+ pump and activation of Na+/Ca2+ exchange in the reverse mode. The obtained data bring us to the conclusion that the metabolic regulation of cell hydration in excitable tissue is realized by the activation of electrogenic Na+/K+ pump and Na+/Ca2+ exchange in the cell membrane and the formation of endogen water by mitochondrial activity, while the regulation of cell hydration in non-excitable tissue is carried out only by the activity of mitochondrial function. Aging leads to an over-expression of Na+/K+ pump units in liver and Na+/Ca2+ exchanger in brain cortex of rats.
组织水合作用的代谢控制是决定细胞功能活性的基本参数,其功能障碍是包括衰老在内的任何细胞病理学的常见后果。本研究的目的是揭示大脑皮层等易兴奋组织与肝脏和脾脏等非易兴奋组织细胞水合作用的年龄依赖性代谢控制的差异。为此,通过冷却抑制代谢活性和向动物供应蒸馏水激活代谢活性,通过Na+/K+泵失活和反向激活Na+/Ca2+交换,研究了细胞水合作用在兴奋性和非兴奋性问题中的年龄依赖性敏感性。所获得的数据使我们得出结论,可兴奋组织中细胞水合作用的代谢调节是通过激活细胞膜中的生电Na+/K+泵和Na+/Ca2+交换以及线粒体活性形成内源性水来实现的,而非兴奋性组织中细胞水合作用的调节仅通过线粒体功能的活性来进行。衰老导致大鼠肝脏中Na+/K+泵单元和大脑皮层中Na+/Ca2+交换器的过度表达。
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引用次数: 1
Spectroscopic Characterization of the Interaction between Dopamine and Human Serum Albumin 多巴胺与人血清白蛋白相互作用的光谱表征
Pub Date : 2019-02-27 DOI: 10.4236/OJBIPHY.2019.92009
I. M. Khalid, S. Sharkh, Husain Samamarh, Rania Alfaqeeh, M. Abuteir, Saqer M Darwish
The interactions of HSA with DA have received great attention nowadays due to its significant effect in the biomedical field and overall health. The main aim of this work is to examine the interaction between DA and HSA at physiological conditions. Upon addition of DA to HSA, the fluorescence emission was quenched with quenching constant Kq = 1.32 × 109 L⋅mol−1⋅s−1 and the binding constant of DA with HSA is found to be K = 4.4 × 102 mainly indicating dynamic quenching. The HSA conformation was altered upon binding of DA to HSA with an increase in α-helix and a decrease in β-sheets suggesting unfolding of HSA secondary structure due to weak intermolecular interaction with HSA. In view of the evidence presented, it is important to understand the details of the interactions of HSA with DA which will be crucial in the design of new DA-inspired drugs and help revealing vital details to better understand the HSA’s role as a transporter for many drugs.
HSA与DA的相互作用因其在生物医学领域和整体健康方面的重要作用而受到广泛关注。本研究的主要目的是研究生理条件下DA和HSA之间的相互作用。DA加入HSA后,荧光猝灭常数Kq = 1.32 × 109 L⋅mol−1⋅s−1,DA与HSA的结合常数K = 4.4 × 102,主要表现为动态猝灭。DA与HSA结合后,HSA的构象发生改变,α-螺旋增加,β-片减少,表明由于与HSA的分子间相互作用较弱,HSA二级结构展开。鉴于所提出的证据,了解HSA与DA相互作用的细节是很重要的,这将对设计新的DA启发药物至关重要,并有助于揭示重要细节,以更好地了解HSA作为许多药物的转运体的作用。
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引用次数: 5
Mimicking Bone Chemical Composition Using Economical Materials for X-Ray Imaging Quality Assurance and Educational Purposes 利用经济材料模拟骨骼化学成分,用于x射线成像质量保证和教育目的
Pub Date : 2019-02-25 DOI: 10.4236/OJBIPHY.2019.92006
Shyma M. Alkhateeb
Imaging different bone sites for medical education requires the formation of bone-equivalent materials that mimic bone density. We investigated an economic imaging composition that characterizes bone density in imaging for quality assurance and educational purposes. Four different compositions were tested to reveal the best composition in simulating bone density in X-ray imaging. Hydrated lime was discovered to be the most suitable because it is durable (stiff and does not crumble), easy to source and process, and attenuates imaging X-rays enough to resemble real bone. Hydrated lime provides a significantly better phantom than the other combinations used.
为医学教育成像不同的骨骼部位需要形成模拟骨密度的骨等效材料。我们研究了一种经济成像成分,其特征是骨密度成像的质量保证和教育目的。测试了四种不同的成分,以揭示在x射线成像中模拟骨密度的最佳成分。人们发现,水合石灰是最合适的材料,因为它经久耐用(坚硬且不易破碎),易于获取和加工,并且能充分衰减x射线成像,使其看起来像真正的骨头。水合石灰提供了一个明显更好的幻影比其他组合使用。
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引用次数: 1
The Intrinsic Self-Time of Biosystems 生物系统的内在自时
Pub Date : 2019-02-22 DOI: 10.4236/OJBIPHY.2019.92010
O. Szász, Peter Szigeti, A. Szász
In biological systems, self-time differs from the physical time scale. Biological self-time is the characteristic of individual biosystems and invariantly describes the various dynamic processes in organisms. This biological invariance is introduced by using 2 basic theorems: Allometric scaling and the Weibull psychometric function. Our objective was to precisely describe the timing phenomenon in biosystems and provide a framework to further develop this analogy for other fields.
在生物系统中,自时不同于物理时标。生物自时是个体生物系统的特征,它不变地描述了生物体内的各种动态过程。用异速缩放和威布尔心理测量函数两个基本定理来介绍这种生物不变性。我们的目标是精确地描述生物系统中的时序现象,并为进一步在其他领域发展这种类比提供一个框架。
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引用次数: 4
Bioelectromagnetic Paradigm of Cancer Treatment—Modulated Electro-Hyperthermia (mEHT) 癌症治疗的生物电磁范式——调制电热疗法(mEHT)
Pub Date : 2019-02-22 DOI: 10.4236/OJBIPHY.2019.92008
O. Szász
One of the most frequently applied bioelectromagnetic effects is the deep heating of the living species with EMF energy. Despite its long history, hyperthermia is a rarely applied oncotherapy. The reason is its controversial results and complicated control. One of the solutions is concentrating the electromagnetic energy nanoscopically on the parts of the malignant cells instead of heating up the complete tumor-mass. This approach is a kind of non-uniform energy absorption, providing energy liberation only in the selected regions. The energy-absorption of the malignant cells targets the membranes and creates a situation far from thermal equilibrium. The selection of the malignant cells is based on their decided differences from their healthy counterparts. The distinguishing parameters are the electromagnetic properties of the components of the malignant tissue which are the physiologic differences between the malignant cells and their healthy counterparts. The targets realize nano-range heating, using natural nanoclusters on the cell-membrane without artificially implementing them. This energy absorption generates consequent reactions, like programmed cell-death (apoptosis) continued by immunogenic cell-death involving extended immune reactions.  The applied radiofrequency current is amplitude modulated by time-fractal modulation pattern. The accurately matched impedance realizes the self-selective mechanisms which are promoted by stochastic resonances. This complex method is a new kind of hyperthermia, named mEHT. Our objective is to analyze the problems of the selective, non-equilibrium energy absorption, and present a solution by the electromagnetic mechanisms for an effective and controllable hyperthermia in oncology.
最常用的生物电磁效应之一是利用电动势能量对生物物种进行深度加热。尽管历史悠久,但热疗是一种很少应用的肿瘤治疗方法。究其原因,其结果有争议,控制复杂。其中一个解决方案是将电磁能量集中在纳米级的恶性细胞上,而不是加热整个肿瘤肿块。这种方法是一种非均匀的能量吸收,只在选定的区域提供能量释放。恶性细胞的能量吸收以细胞膜为目标,造成远离热平衡的情况。恶性细胞的选择是基于它们与健康细胞的明显差异。区分参数是恶性组织成分的电磁特性,即恶性细胞与健康细胞之间的生理差异。该靶标利用细胞膜上的天然纳米团簇实现纳米级加热,而无需人工实现。这种能量吸收产生相应的反应,如程序性细胞死亡(细胞凋亡),持续的免疫原性细胞死亡涉及延长的免疫反应。所施加的射频电流采用时间分形调制方式进行幅度调制。精确匹配的阻抗实现了随机共振促进的自选择机制。这种复杂的方法是一种新的热疗方法,被称为mEHT。我们的目的是分析选择性、非平衡能量吸收的问题,并提出一种有效的、可控的肿瘤热疗的电磁机制解决方案。
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引用次数: 10
Determination of the Optical Properties of Basal Cancer Using OCT System 利用OCT系统测定基底癌的光学性质
Pub Date : 2019-02-22 DOI: 10.4236/ojbiphy.2019.92007
S. S. Elwakeel, N. Almuslet, Yahia Badr Aldeen, K. M. Haroun
The objective of this work is to determinate the optical properties of basal cancer cells using an optical coherence tomography (OCT). OCT system with He-Ne & diode laser was used to make interference pattern for the basal cancer, then the output was displayed by optical detector, information of an electrical signal passed to the digital oscilloscope to give the object information after Fourier transform processing for that signal, then PC and CCD were used to display FFT signal. Finally many steps were done to determine the optical properties for the basal cancer. The intensity of the signals was plotted against scanning distance; the obtained graphs were used to determine the penetration depth and absorption coefficient.
这项工作的目的是利用光学相干断层扫描(OCT)确定基底癌细胞的光学特性。利用氦氖二极管激光器的OCT系统对基底癌进行干涉图样的制作,输出到光学探测器上显示,电信号经过傅里叶变换处理后传递给数字示波器给出目标信息,然后用PC机和CCD进行FFT信号的显示。最后进行了许多步骤来确定基底癌的光学性质。信号强度随扫描距离绘制;利用所得图确定了渗透深度和吸收系数。
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引用次数: 0
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生物物理学期刊(英文)
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