Structural changes

结构变化
  • 文章类型: Journal Article
    背景:胆碱氧化酶,一种黄素蛋白,是一种催化将胆碱转化为甘氨酸甜菜碱的反应的酶。胆碱氧化酶始于1933年。然而,尽管其晶体结构具有悠久的历史和可用性,但尚未探索高温对其结构的影响。胆碱氧化酶及其产物,甘氨酸甜菜碱,拥有跨越多个行业的巨大应用。了解酶的3D结构如何随温度变化而变化,可以开辟新的途径,使其更稳定,更有用。
    方法:本研究论文介绍了在25°C至60°C的温度下,球形A胆碱氧化酶结构变化的计算机研究和分析。在图1中描绘了一个逐步的过程。1.
    结果:来自不同细菌的11个胆碱氧化酶序列与球形节杆菌胆碱氧化酶的多序列比对(MSA)表明,活性位点残基高度保守。对于分子动力学模拟,考虑了具有处于二聚体状态的辅因子黄素腺嘌呤二核苷酸(FAD)1(PDBID:4MJW)1的球形曲霉胆碱氧化酶的可用晶体结构。使用模拟退火选项将系统的温度从25°C逐渐增加到60°C。分析保守的残基,以及涉及黄素腺嘌呤二核苷酸(FAD)结合的残基,底物结合,子状态门控,二聚体形成完成。在高温下,Arg50和Glu63之间链间盐桥的形成是胆碱氧化酶活性位点附近的重要观察结果。
    结论:分子动力学研究表明,温度升高对延伸的黄素腺嘌呤二核苷酸(FAD)结合区具有显着影响。这些变化干扰底物进入酶的活性位点并使酶失活。
    BACKGROUND: Choline oxidase, a flavoprotein, is an enzyme that catalyzes the reaction which converts choline into glycine betaine. Choline oxidase started its journey way back in 1933. However, the impact of the high temperature on its structure has not been explored despite the long history and availability of its crystal structure. Both choline oxidase and its product, glycine betaine, have enormous applications spanning across multiple industries. Understanding how the 3D structure of the enzyme will change with the temperature change can open new ways to make it more stable and useful for industry.
    METHODS: This research paper presents the in-silico study and analysis of the structural changes of A. globiformis choline oxidase at temperatures from 25 °C to 60 °C. A step-wise process is depicted in Fig. 1.
    RESULTS: Multiple sequence alignment (MSA) of 11 choline oxidase sequences from different bacteria vs Arthrobacter globiformis choline oxidase showed that active site residues are highly conserved. The available crystal structure of A. globiformis choline oxidase with cofactor Flavin Adenine Dinucleotide (FAD) in the dimeric state (PDB ID: 4MJW)1 was considered for molecular dynamics simulations. A simulated annealing option was used to gradually increase the temperature of the system from 25 °C to 60 °C. Analysis of the conserved residues, as well as residues involved in Flavin Adenine Dinucleotide (FAD) binding, substrate binding, substate gating, and dimer formationwas done. At high temperatures, the formation of the inter-chain salt bridge between Arg50 and Glu63 was a significant observation near the active site of choline oxidase.
    CONCLUSIONS: Molecular dynamics studies suggest that an increase in temperature has a significant impact on the extended Flavin Adenine Dinucleotide (FAD) binding region. These changes interfere with the entry of substrate to the active site of the enzyme and make the enzyme inactive.
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  • 文章类型: Journal Article
    本研究的目的是全面分析Xe23重离子辐照的不同通量对结构变化的影响,光学,和AlN陶瓷的强度性能,并在结构变形与陶瓷的光学和机械性能变化之间建立联系。X射线衍射,紫外-可见和拉曼光谱,采用压痕和单压缩方法作为研究方法。在研究期间,事实证明,在低辐照通量下,在AlN陶瓷的性质变化的主要作用是由相关的影响,在其光学性质的变化和基本的吸收边移,表征陶瓷电子特性的变化(电子密度分布的变化)。对所检查样品的光学特性相对于辐照通量的变化的研究表明,当通量超过5×1011离子/cm2时,光谱外吸收带出现在3.38-3.40eV的范围内。该条带对于在受损层的结构内产生空位ON-VAl络合物是独特的。这些复合物的存在表示结构变形和受损层内缺陷夹杂物的积累。对晶格参数变化的分析表明,受损层中的结构变形是由于拉伸残余机械应力的累积所致,浓度的增加导致受损层的膨胀和破坏。陶瓷的机械性能与辐照通量之间的某些相关性表明,陶瓷对辐射引起的脆性和弱化具有显着的抵抗力。只有当结构损伤累积时,这些影响才会变得明显,导致晶格的溶胀超过2.5-3%。
    The purpose of this study is to comprehensively analyze the influence of different fluences of irradiation with Xe23+ heavy ions on alterations in the structural, optical, and strength properties of AlN ceramics and to establish a connection between structural distortions and alterations in the optical and mechanical properties of the ceramics. X-ray diffraction, UV-Vis and Raman spectroscopy, and indentation and single-compression methods were used as research methods. During the study, it was demonstrated that at low irradiation fluences, the main role in the changes in the properties of the AlN ceramics is played by effects related to changes in their optical properties and a fundamental absorption edge shift, which characterizes changes in the electronic properties of the ceramics (changes in the distribution of electron density). A study of the variations in the optical properties of the examined samples in relation to the irradiation fluence showed that when the fluence surpasses 5 × 1011 ion/cm2, an extra-spectral absorption band emerges within the range of 3.38-3.40 eV. This band is distinctive for the creation of vacancy ON-VAl complexes within the damaged layer\'s structure. The presence of these complexes signifies structural deformations and the accumulation of defective inclusions within the damaged layer. An analysis of changes in the parameters of the crystal lattice showed that structural distortions in the damaged layer are due to the accumulation of tensile residual mechanical stresses, an increase in the concentration of which leads to the swelling and destruction of the damaged layer. Some correlations between the mechanical properties of ceramics and the irradiation fluence indicate the ceramics\' remarkable resistance to radiation-induced brittleness and weakening. These effects become apparent only when structural damage accumulates, resulting in the swelling of the crystal lattice exceeding 2.5-3%.
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  • 文章类型: Journal Article
    在本文中,在不同的总固体浓度(1-4%TS)下评估了几种织物的嗜温生化甲烷潜力。应用物理化学技术探讨了厌氧消化过程中纤维的结构变化。此外,使用改进的Gompertz模型来评估和比较织物的AD性能。在纤维素基纤维中,由于乙酸盐的容易溶解,沼气的产生得到了提高,它是在纤维素键部分断裂时产生的。植物纤维的结晶度从第19天开始显著降低。在最低TS浓度下,丝绸和羊毛织物的甲烷产率最高。检测到丝纤蛋白和角蛋白的构象变化。在具有较低固体浓度的固体样品中观察到最高程度的降解。因此,在以较低TS操作的反应器中报告了最大甲烷产率。
    In this paper, the mesophilic Biochemical Methane Potential of several fabrics was assessed at different Total Solid concentrations (1-4%TS). Physico-chemical techniques were applied to explore the arising structural changes on fibers during the anaerobic digestion process. Additionally, the modified Gompertz model was used to assess and compare the AD performance of the fabrics. In cellulose-based fibers the production of biogas was enhanced thanks to the easy solubilization of acetate, which is generated upon partial breakage of cellulose bonds. The crystallinity of vegetal fibers decreased significantly from day 19. The highest methane yields were attained for silk and wool fabrics at the lowest TS concentrations. Conformational changes in fibroin and keratin were detected. The highest degrees of degradation were observed in solid samples with lower solid concentrations. Accordingly, the maximum methane yields were reported in the reactors operating with lower TS.
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  • 文章类型: Journal Article
    在一些研究中,中风被认为会增加痴呆的风险,但大脑结构改变与卒中后认知障碍(PSCI)之间的关系尚不清楚。
    在这项研究中,2周后23例PSCI基底神经节梗死患者和29例年龄匹配的对照者接受磁共振成像测量皮质厚度和体积变化,以及神经心理学测试。CI来源于正态分布得分的表现得分<1.5个标准差。我们比较了两组不同认知域的Z评分以及皮质厚度和体积。使用多元线性回归来研究皮质厚度与体积之间的关系以及神经心理学测试。
    大多数PSCI患者年龄在50多岁(55.19±8.52岁)。PSCI患者在多个领域表现出显著降低的Z评分,比如记忆,语言,视觉运动速度,和注意力/执行功能。后部中体的体积,中前call体,PSCI患者海马明显低于对照组。右侧颞下皮质和脑岛的厚度明显小于对照组。发现右海马减少与执行功能障碍有关。海马功能障碍可能与PSCI患者基底节梗死的语言障碍有关(p<0.05)。
    这些研究结果表明,缺血性卒中后大脑结构发生了改变,不同的灰质结构改变可能导致PSCI患者基底神经节梗死的特异性认知功能下降。右海马萎缩可能是PSCI早期执行功能的成像标记。
    UNASSIGNED: Stroke has been considered to raise the risk of dementia in several studies, but the relationship between brain structural changes and poststroke cognitive impairment (PSCI) is unclear.
    UNASSIGNED: In this study, 23 PSCI patients with basal ganglia infarcts after 2 weeks and 29 age-matched controls underwent magnetic resonance imaging measuring cortical thickness and volume changes, as well as neuropsychological tests. CI was derived from a performance score <1.5 standard deviations for normally distributed scores. We compared Z scores in different cognitive domains and cortical thickness and volumes in two groups. Multiple linear regressions were used to investigate the relationship between cortical thickness and volumes and neuropsychological tests.
    UNASSIGNED: A majority of PSCI patients were in their 50s (55.19±8.52 years). PSCI patients exhibited significantly decreased Z scores in multiple domains, such as memory, language, visuomotor speed, and attention/executive function. The volumes of the middle posterior corpus callosum, middle anterior corpus callosum, and hippocampus in PSCI patients were markedly lower than controls. The thickness of the right inferior temporal cortex and insula were significantly smaller than controls. It found that the reduced right hippocampus was related to executive dysfunction. Hippocampus dysfunction may be involved in language impairment (p<0.05) in PSCI patients with basal ganglia infarcts.
    UNASSIGNED: These findings demonstrated that brain structure changed after ischemic stroke, and different gray-matter structural changes could lead to specific cognitive decline in PSCI patients with basal ganglia infarcts. Atrophy of the right hippocampus potentially serves as an imaging marker of early executive function of PSCI.
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  • 文章类型: Journal Article
    The occurrence of sulfur in coal direct liquefaction residue affects its further high quality and high value utilization. Electrochemical desulfurization is characterized by mild reaction conditions, simple operation, easy separation of sulfur conversion products and little influence on the properties of the liquefied residue. An anodic electrolytic oxidation desulphurization experiment was carried out on the liquefaction residue of the by-product of a coal-to-liquid enterprise in the slurry state. An electrochemical test and material characterization of raw materials before and after electrolysis showed that electrolytic oxidation can desulfurize the liquefaction residue under an alkaline condition. Linear sweep voltammetry (LSV) was used for the electrolysis experiments to obtain the optimal slurry concentration of 60 g/L. On this basis, the reaction kinetics were calculated, and the minimum activation energy in the interval at 0.9 (V vs. Hg/HgO) was 19.71 kJ/mol. The relationship between the electrolytic desulfurization of the liquefied residue and energy consumption was studied by the potentiostatic method. The influence of anodic potential and electrolytic temperature on the current density, cell voltage, desulfurization rate and energy consumption was investigated. The experimental results showed that the desulfurization rate and total energy consumption increase positively with the increase in reaction temperature and electrolytic potential in a certain range. The influence of the reaction temperature on the desulfurization rate and total energy consumption is more prominent than that of electrolytic potential, but the energy consumption of sulfur removal per unit mass does not show a positive correlation. Therefore, with the energy consumption per unit mass of sulfur removal as the efficiency index, the optimal experimental results were obtained: under the conditions of 0.8 (V vs. Hg/HgO) anode potential, 50 °C electrolytic temperature, 60 g/L slurry concentration and 14,400 s electrolytic time, the desulfurization rate was 18.85%, and the power consumption per unit mass of sulfur removal was 5585.74 W·s/g. The results of XPS, SEM, BET and IC showed that both inorganic and organic sulfur were removed by electrolytic oxidation, and the morphology, pore structure and chemical bond of the liquefied residue were affected by electrolytic oxidation. The research method provides a new idea and reference for the efficiency evaluation of desulfurization and hydrogen production from coal liquefaction residue.
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  • 文章类型: Journal Article
    UNASSIGNED:这项研究的目的是调查与全膝关节置换术(TKA)发生最密切相关的骨关节炎危险因素随时间的变化。我们假设纵向病例对照研究的稳健性将提供有关TKA之前不同时间范围内各种临床和结构参数变化之间关联的新信息。
    未经评估:病例(195;进入队列后的TKA)和对照(468)年龄匹配,性别,收入,WOMAC疼痛,Kellgren-Lawrence分级和随访时间来自骨关节炎倡议队列。社会人口变化之间的关联,临床,使用条件logistic回归分析对发生TKA的影像学和骨关节炎治疗进行了分析.
    UNASSIGNED:WOMAC分数的恶化(cOR1.02-1.20,第0.012页),KOOS(1.02-1.04,第0.014页),膝关节损伤持续30~40年(女性2.70,p=0.034)和外翻对齐(1.10,p=0.052)与TKA的发生相关.同样与TKA相关的是外侧软骨体积损失(总体1.76,p=0.025;女性1.93,p=0.047)和内侧隔室(10%,总体1.54,p=0.027;男性2.34,p=0.008),发生内侧半月板脱出(总体1.77,p=0.046;男性2.86,p=0.028),女性的骨髓病变(BMLs)增加(1.09,p=0.048)。当WOMAC疼痛增加和软骨体积损失(1.85,p=0.001)相结合时,危险因素与TKA的关联得到加强。止痛药的使用,主要是麻醉剂和关节内类固醇注射(IASI),也与TKA有关,对软骨损失或结构的变化没有影响。
    UNASSIGNED:这项研究提供了有关与TKA发生相关的危险因素的性别差异的新信息。外翻对准恶化,外侧隔室软骨体积损失,BMLs和老年损伤是女性的重要危险因素,而男性的内侧间室软骨丢失和半月板挤压。止痛药和IASI的使用尽管与TKA无关,但与TKA无关。
    UNASSIGNED: The aim of this study was to investigate changes over time in osteoarthritis risk factors most closely associated with the occurrence of total knee arthroplasty (TKA). We hypothesize that the robustness of a longitudinal case-control study will provide new information on the association between changes in various clinical and structural parameters in different time frames before TKA.
    UNASSIGNED: Cases (195; TKA after cohort entry) and controls (468) matched for age, gender, income, WOMAC pain, Kellgren-Lawrence grade and follow-up duration were from the Osteoarthritis Initiative cohort. Associations between changes in sociodemographic, clinical, imaging and osteoarthritis therapies with the occurrence of TKA were performed using conditional logistic regression analyses.
    UNASSIGNED: Worsening of WOMAC scores (cOR 1.02-1.20, p ⩽ 0.012), KOOS (1.02-1.04, p ⩽ 0.014), knee injuries sustained in the previous 30-40 years (women 2.70, p = 0.034) and valgus alignment (1.10, p = 0.052) were associated with the occurrence of TKA. Also associated with TKA was cartilage volume loss in the lateral (overall 1.76, p = 0.025; women 1.93, p = 0.047) and medial compartments (⩾10%, overall 1.54, p = 0.027; men 2.34, p = 0.008), occurrence of medial meniscal extrusion (overall 1.77, p = 0.046; men 2.86, p = 0.028), and increase in bone marrow lesions (BMLs) for women (1.09, p = 0.048). The association of risk factors with TKA was reinforced when both an increase in WOMAC pain and cartilage volume loss (1.85, p = 0.001) were combined. Pain medication usage, mainly narcotics and intra-articular steroid injections (IASI), was also associated with TKA, with no impact on changes in cartilage loss or structure.
    UNASSIGNED: This study provides new information about gender differences in risk factors associated with the occurrence of TKA. Worsening of valgus alignment, cartilage volume loss in the lateral compartment, BMLs and older injuries are important risk factors in women, while medial compartment cartilage loss and meniscal extrusion are in men. The use of pain medication and IASI although associated was found not causal with TKA.
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  • 文章类型: Journal Article
    目的:热休克蛋白90(Hsp90)是一种调节免疫反应的分子伴侣。我们旨在评估全身性Hsp90作为脊柱关节炎(SpA)的生物标志物。材料和方法:包括总共80例轴向SpA(axSpA)和22例银屑病关节炎患者以及相应数量的年龄和性别匹配的健康对照(HC)。通过ELISA测量血浆Hsp90水平。结果:与HC相比,axSpA患者的Hsp90显着增加(四分位距中位数:15.7[10.5-19.8]vs8.3[6.6-11.8]ng/ml,p<0.001)。此外,Hsp90在区分axSpA(以及放射学axSpA[r-axSpA]和非放射学axSpA)与HC方面优于C反应蛋白。r-axSpA患者Hsp90水平与骶髂关节骨髓水肿相关(r=0.594,p=0.019)。结论:Hsp90可能成为r-axSpA活动性炎症的生物标志物,与C反应蛋白相比,可以更好地区分axSpA患者与健康受试者。
    Aim: Heat shock protein 90 (Hsp90) is a molecular chaperone regulating immune response. We aimed to assess systemic Hsp90 as a biomarker for spondyloarthritis (SpA). Materials & methods: Total of 80 axial SpA (axSpA) and 22 psoriatic arthritis patients and a corresponding number of age- and sex-matched healthy controls (HC) were included. Plasma Hsp90 levels were measured by ELISA. Results: Hsp90 was significantly increased in axSpA patients compared with HC (median interquartile range: 15.7 [10.5-19.8] vs 8.3 [6.6-11.8] ng/ml, p < 0.001). Moreover, Hsp90 was superior to C-reactive protein in differentiating axSpA (and both radiographic axSpA [r-axSpA] and nonradiographic-axSpA) from HC. Hsp90 levels correlated with bone marrow edema of sacroiliac joints in r-axSpA patients (r = 0.594, p = 0.019). Conclusion: Hsp90 could become a biomarker for active inflammation in r-axSpA, and can better distinguish axSpA patients from healthy subjects than C-reactive protein.
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    文章类型: Journal Article
    Malignant tumors of the eye and its adnexa (C69) are rare malignancies. To date state statistics in Russia (Form No. 7) have data only for estimating the incidence of the population. These data, at our proposal, were included in Form No. 7 only since 2011. In 2018 for the first time we were able to have data on the incidence of the population by age separately for men and women but only in Russia as a whole. The estimation of rates of a 1- and 5-year patient survival for this pathology is carried out only by us in the North-West Federal Region of Russia, where, in February 2019, we have formed the first Population-based Cancer Registry (PCR) in Russia at the Federal Region\'s level with a total database of more than 1 million cases. Previously similar work was conducted on the materials of the Population-based Cancer Registry of Saint-Petersburg. For the first time this work presents the features of data on changes in the structure of oncological pathology of the eye and its adnexa (C69) and estimations of a 5-year survival by age. Unfortunately the Office of the Federal State Statistics Service classifies the pathology of the eye (C69) as a group of «other malignant tumors» and does not publish mortality data. At the same time, using the PCR database, it must be borne in mind that index accuracy (the ratio of a number of deaths to a number of sick for the first time in life) according to malignant tumors of the eye (C69) is about 0,50% and is constantly decreasing.
    Злокачественные новообразования глаза и его придаточного аппарата (С69) относятся к редким опухолям. До настоящего времени государственная статистика в России (ф. № 7) «Сведения о злокачественных новообразованиях» располагает данными только для расчета заболеваемости населения. Эти данные были включены в ф. № 7 по нашему предложению только с 2011 г. В 2018 г. мы впервые смогли располагать данными о заболеваемости населения по возрасту отдельно для мужчин и женщин, но только в целом по России. Такая возможность имеется и у каждого территориального ракового регистра. Расчет показателей одно- и пятилетней выживаемости больных по этой патологии осуществляется только нами по 10 административным территориям Северо-Западного федерального округа, где в феврале 2019 г. был нами сформирован первый в России Популяционный раковый регистр (ПРР) на уровне федерального округа с общим объемом базы данных более 1 млн наблюдений. Ранее аналогичные работы осуществлялись только на материалах ПРР Санкт-Петербурга. В настоящей работе впервые представлены особенности изменения структуры онкологической патологии глаза и его придаточного аппарата (С69) и расчеты пятилетней выживаемости по возрасту. К сожалению, Управление Федеральной службы государственной статистики относит патологию глаза (С69) к группе «прочие ЗНО» и не публикует данные о смертности. Вместе с тем, используя базу данных ПРР, нужно иметь в виду, что индекс достоверности учета (отношение числа умерших к числу впервые в жизни заболевших) по ЗНО глаза (С69) составляет около 0,50% и постоянно снижается, а достоверность учета повышается.
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  • 文章类型: Journal Article
    Study of nanostructure-protein interaction for development of various types of nano-devices is very essential. Among carbon nanostructures, carbon nanotube (CNT) provides a suitable platform for functionalization by proteins. Previous studies have confirmed that the CNT induces changes in the protein structure.
    Molecular dynamics (MD) simulation study was employed to illustrate the changes occurring in the protein G (PGB) in the presence of a CNT. In order to predict the PGB surface patches for the CNT, Autodock tools were utilized.
    Docking results indicate the presence of two different surface patches with diverse amino acids: the dominant polar residues in the first (PGB-CNT1) and the aromatic residues in the second (PGB-CNT2) surface patch. Displacement of amino acids in the PGB-CNT2 complex occurred during the simulation and it caused an increase in its stability at the end of simulation. The amino acids\' displacements diminished the PGB α-helix structure by breakage of hydrogen bonds and generated more transient structures. Principal component analysis determined that the interaction of the CNT with the second surface patch of the PGB raised the extent and modes of the PGB motions. In contrast, insignificant structural changes induced in the PGB while the CNT bonded through the first surface patch.
    Even though neither of the PGB-CNT complexes could prevent structural changes in the PGB, development of the PGB-CNT1 complex induce slight structural changes in its fragment of crystallizable receptor (FCR). Dissimilar structural changes induced in the PGB-CNT complexes are possibly related to various characteristics of the PGB binding sites.
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  • 文章类型: Journal Article
    A recent study has shown that striatal silent infarction may occur secondary to the degeneration of dopaminergic neurons in the substantia nigra (SN) of mice. However, it is uncertain whether this phenomenon occurs in patients with early-stage Parkinson\'s disease (PD) and can be detected by diffusion kurtosis imaging (DKI). A total of 72 untreated patients with early-stage PD underwent conventional MRI and DKI. Participants were divided into control and striatal silent lacunar infarction (SSLI) groups. The differences in mean kurtosis (MK) values of the SN, Hoehn-Yahr (H-Y) staging, and Unified Parkinson\'s Disease Rating Scale (UPDRS) III score between groups, were analyzed. Linear regression analysis was used to correlate age, SSLI count, silent lacunar infarction count in other brain areas and age-related white matter change score with MK values of the SN. Spearman correlation coefficient analysis was used to correlate MK values of the SN and SSLI count with H-Y staging and UPDRS III score. There was no significant difference in the severity of disease between two groups; however, MK values of the SN with SSLI present were significantly higher than in SN without SSLI. In addition, SSLI count had linear correlation with MK values of the SN, which had positive correlation with H-Y-staging and UPDRS III score. SSLI is associated with structural changes to the SN in patients with early-stage PD, detectable by DKI, and may aggravate their motor impairments.
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