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Prediction of thermodynamic properties oflanthanide/transition metal alloys by deep learning 通过深度学习预测镧系元素/过渡金属合金的热力学性质
Pub Date : 2024-07-16 DOI: 10.31276/vjst.2024.0006
Tien Lam Pham, Tien-Cuong Nguyen, Van Quyen Nguyen
The utilization of machine learning, especially deep learning, in solving materials science issues bring an opportunity to accelerate the development process of new materials and draw the attention of researchers all over the world. In this work, we present our study on applying deep neural networks to represent and predict thermodynamic quantities including formation energy, convex hull distance, and to recognize potential thermodynamical stabile materials. We employ our novel material descriptor, named orbital field matrix (OFM), to determine the feature vectors for materials. The OFM descriptors were developed based on the information of valence electron configuration and the Voronoi analysis of the atomic structures of materials. Our experiments show that deep neural networks can accurately predict formation energyand convex hull distancewith the mean absolute error around 0,124eV/atom and 0,105 eV/atom, respectively. In addition,the classification neural network can yield an accuracy of 92% in distinguishing the stable and unstable materials.
利用机器学习,尤其是深度学习来解决材料科学问题,为加速新材料的开发进程带来了机遇,并引起了全世界研究人员的关注。在这项工作中,我们介绍了应用深度神经网络表示和预测热力学量(包括形成能、凸壳距离)以及识别潜在热力学稳定材料的研究。我们采用名为轨道场矩阵(OFM)的新型材料描述符来确定材料的特征向量。轨道场矩阵描述符是基于价电子构型信息和材料原子结构的沃罗诺分析而开发的。实验结果表明,深度神经网络可以准确预测形成能和凸壳距离,平均绝对误差分别约为 0,124eV/atom 和 0,105 eV/atom。此外,分类神经网络在区分稳定和不稳定材料方面的准确率高达 92%。
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引用次数: 0
Study on the effect of freezing pretreatment and endogenous fermentation on the quality and processing time of black shallots using moist heat treatment method 利用湿热处理法研究冷冻预处理和内源发酵对黑香葱品质和加工时间的影响
Pub Date : 2024-07-03 DOI: 10.31276/vjst.2024.0005
Phuong Chi Tran, Thi Le Hang Hoang, Dinh Thang Tran
Black shallots are new products made by processing fresh shallots (Allium ascolanicumL.) under controlled temperature and humidity conditions without the use of additives. The purpose of this study was to determine suitable freezing pretreatment and endogenous fermentation conditions (treatment temperature, treatment time) to break down the cell structure in raw materials, to promote reactions caused by enzyme (hydrolysis reaction of polysaccharides, proteins, reaction of converting polyphenol compounds in bound form to free form...), improving the content of nutritional ingredients and active ingredients in black shallotproducts and shorten fermentation time. The results have determined that the suitable freezing pretreatment condition at a temperature of -20oC for 30 hours and the suitable endogenous fermentation condition at a temperature of 45oC for 2 days. Under these conditions, the black shallotproducts achieved good quality, corresponding to the total fermentation time shortened to 17 days compared to the control which was 24 days. This research initially gave feasibility for black shallotproduction on an industrial scale.
黑香葱是在不使用添加剂的情况下,在可控温度和湿度条件下加工新鲜香葱(Allium ascolanicumL.)而制成的新产品。本研究的目的是确定合适的冷冻预处理和内源发酵条件(处理温度、处理时间),以破坏原料中的细胞结构,促进酶引起的反应(多糖、蛋白质的水解反应,多酚化合物以结合态转化为游离态的反应......),提高黑葱产品中营养成分和活性成分的含量,并缩短发酵时间。研究结果表明,适宜的冷冻预处理条件是在零下 20 摄氏度的条件下持续 30 小时,适宜的内源发酵条件是在 45 摄氏度的条件下持续 2 天。在这些条件下,黑香葱产品获得了良好的品质,与对照组的 24 天相比,总发酵时间缩短到 17 天。这项研究初步提出了工业化生产黑香葱的可行性。
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引用次数: 0
Comprehensive analysis of cement-stabilised dredged marine soil: Evaluating physical, microstructural, and mechanical characteristics 全面分析水泥稳定疏浚海洋土壤:评估物理、微观结构和机械特性
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).52-60
Bhim Kumar Dahal, Jun Jie Zheng
This study evaluates the index, microstructural, and mechanical behaviour of cement-stabilised soft soil. The marine soil dredged from Hangzhou is taken for the study. Different percentages of ordinary Portland cement (OPC)by dry mass were added to the soils during reconstitution, i.e., 5, 10, 15, and 20%. The reconstituted samples were analysed in the laboratory to determine basic properties such as moisture content, void ratio, density, specific gravity, consistency limits, and particle size distribution. The microstructures of the reconstituted samples were also evaluated through scanning electron microscopy. Results inferred a significant impact on the physical properties of the soil. An increase in cement content increases the consistency limits. Additionally, the specific gravity, plasticity index, and density of the treated soil initially decreased but increased upon further addition of cement content. The microstructure of the soil transformed from a dispersed to a flocculated structure, with larger and denser particles. The change in microstructure was also evident in the particle size distribution, with an increase in cement content leading to larger size particles. Finally, the unconfined compression test conducted on the reconstituted soil indicates a substantial enhancement in strength with higher cement content and prolonged curing periods.
本研究评估了水泥稳定软土的指标、微观结构和力学性能。研究采用的是杭州疏浚的海洋土壤。在重组过程中,向土壤中添加了不同比例的普通硅酸盐水泥(OPC),即 5%、10%、15% 和 20%。重组后的样品在实验室进行分析,以确定其基本属性,如含水量、空隙率、密度、比重、稠度极限和粒径分布。还通过扫描电子显微镜对重组样品的微观结构进行了评估。结果表明,水泥对土壤的物理性质有重大影响。水泥含量的增加会提高稠度极限。此外,经过处理的土壤的比重、塑性指数和密度最初都有所下降,但随着水泥含量的进一步增加,其比重、塑性指数和密度都有所上升。土壤的微观结构从分散结构转变为絮凝结构,颗粒更大、更致密。微观结构的变化在粒径分布上也很明显,水泥含量的增加导致粒径变大。最后,对重组土壤进行的无约束压缩测试表明,随着水泥含量的增加和固化时间的延长,土壤的强度会大幅提高。
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引用次数: 0
Stochastic modelling of material variability in structural dynamics: A threefold comparison of Monte Carlo, polynomial chaos, and random sampling techniques 结构动力学中材料可变性的随机建模:蒙特卡罗、多项式混沌和随机抽样技术的三重比较
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).33-51
Rakesh Kumar
This article investigates the influence of random elastic modulus on beam eigenfrequencies using multiple simulation techniques: Monte Carlo simulations (employing Cholesky decomposition (MCS-CD) and Kosambi-Karhunen-Loève expansion (MCS-KKL)), Polynomial Chaos expansion (PCE), and a proposed Random Sampling method (RSM). Anomalies in Monte Carlo simulations, where normally distributed elastic modulus led to negative values and imaginary eigenfrequencies, were effectively addressed by adopting a log-normal distribution. Comparative analyses focused on covariance variation of the first three eigenfrequencies with correlation length and standard deviation of the random field, highlighting nuanced differences between normal and log-normal distributions. PCE exhibited distinct responses, showcasing variations in covariance with different distributions. The study culminates in eigenfrequency estimation using the proposed RSM, wherein the beam is discretised into n elements with randomly assigned elastic moduli. The mean and variance of eigenfrequencies are compared with existing methods, which represent an alternative method for achieving similar outcomes.These comparative studies provide a comprehensive understanding of how different statistical treatments and simulation methods impact the reliability and accuracy of eigenfrequency predictions in beams with random elastic properties, thus contributing valuable insights for structural analysis and design under uncertainty.
本文采用多种模拟技术研究了随机弹性模量对梁特征频率的影响:蒙特卡罗模拟(采用 Cholesky 分解 (MCS-CD) 和 Kosambi-Karhunen-Loève 扩展 (MCS-KKL))、多项式混沌扩展 (PCE) 和拟议的随机抽样方法 (RSM)。在蒙特卡罗模拟中,正态分布的弹性模量会导致负值和虚特征频率,而采用对数正态分布则能有效解决这一问题。比较分析侧重于前三个特征频率与随机场的相关长度和标准偏差的协方差变化,突出了正态分布和对数正态分布之间的细微差别。PCE 表现出不同的反应,展示了不同分布的协方差变化。研究的高潮是使用所提出的 RSM 估算特征频率,其中梁被离散为 n 个随机分配弹性模量的元素。这些比较研究让人们全面了解了不同的统计处理和模拟方法如何影响具有随机弹性特性的梁的特征频率预测的可靠性和准确性,从而为不确定条件下的结构分析和设计提供了宝贵的见解。
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引用次数: 0
GPR investigation of the cause of persistent failure of a university road 对一条大学路持续塌方原因的 GPR 勘察
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).114-120
Muslim Babatunde Aminu, Femi Ologunaye
We present the results of a multi-frequency ground-penetrating radar (GPR) survey over a university road in south-western Nigeria that has experienced persistent failures. The goal was to evaluate causes of failure to aid remediation efforts. Data was collected concurrently at 250, 500, and 1000 MHz using a UTSI electronic trivue system. Data were processed and interpreted using Reflex-Win. Visual observations of major features apparent on the road surface including failed sections were noted. Imaged features included possible bases of the surface course, base course and sub-base, subsurface projections of an outcropping and buried basement rocks, three deeply cut and back-filled sections that lie beneath sections of the road that have experienced persistent failure, and the ringing effects and rebar-associated reflection hyperbolae of two reinforced concrete drains. Indications of preferential wetting of the shallow subsurface beneath much of the failed sections suggest that failure is due to excessive moisture content in these sections. These failed sections generally correspond to regions of deep cut and backfill, and regions cut and filled for the construction of reinforced concrete drains. Apparently, the backfills at these locations have failed to prevent water influx into the subsurface and more effective remediation measures need to be deployed.
我们介绍了对尼日利亚西南部的一条大学路进行多频率探地雷达(GPR)勘测的结果,这条大学路一直存在故障。目的是评估故障原因,以帮助修复工作。使用 UTSI 电子测量系统,以 250、500 和 1000 MHz 频率同时采集数据。数据使用 Reflex-Win 进行处理和解释。对路面上明显的主要特征(包括塌陷路段)进行了目测观察。图像特征包括可能的表层路面、基层和底层路面的基底,露头和埋藏的基底岩石的地表下凸起,位于经历过持续塌方的路段下方的三个深度切割和回填路段,以及两个钢筋混凝土排水沟的环形效应和与钢筋相关的反射双曲线。大部分塌陷路段下方的浅层地表有优先湿润的迹象,这表明塌陷是由于这些路段的含水量过高造成的。这些坍塌地段一般都位于深挖回填区域,以及为修建钢筋混凝土排水沟而切割和填埋的区域。显然,这些地方的回填土未能防止水流入地下,需要采取更有效的补救措施。
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引用次数: 0
Convective heat transfer by nanofluid jet impingement cooling on automobile radiator with nozzle plate spacing 汽车散热器上纳米流体射流撞击冷却的对流传热(喷嘴板间距
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).10-18
M. Peeraiah, K. N. Rao, B. Balakrishna
Nanofluids are a type of emerging heat transfer fluid with great promise for thermal engineering due to its high heat transfer coefficients. Improving heat transmission remains an ongoing task in engineering fields as diverse as semiconductor technology and high-performance vehicles. This paper investigates and compares the jet impact heat transfer coefficient, thermal conductivity, and viscosity of nanofluids with those of a base fluid in an automobile radiator with nozzle plate spacing. Aluminium oxide (Al2O3) and deionised water were selected as the working fluids, and they were used in varying quantities ranging from 0 to 1 volume percent. The nanofluids were prepared using a two-step method with the aid of an ultrasonic homogeniser. The results reveal that the heat transfer coefficient increased by 11.68% at a nanofluid concentration of 1% when nanoparticles were suspended in the base fluid. Furthermore, a 45-49% improvement in the heat transfer coefficient was recorded using a nanoparticle volume concentration of 1% compared to the base fluid.
纳米流体是一种新兴的传热流体,因其传热系数高而在热能工程领域大有可为。在半导体技术和高性能汽车等各种工程领域,改善热传递仍然是一项持续的任务。本文研究并比较了具有喷嘴板间距的汽车散热器中纳米流体与基础流体的喷射冲击传热系数、热导率和粘度。工作流体选择了氧化铝(Al2O3)和去离子水,使用量从 0 到 1 体积百分比不等。纳米流体的制备采用超声波匀浆器辅助的两步法。结果表明,当纳米颗粒悬浮在基础流体中的纳米流体浓度为 1%时,传热系数提高了 11.68%。此外,与基础流体相比,纳米颗粒体积浓度为 1%时,传热系数提高了 45-49%。
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引用次数: 0
Chemical constituents, antioxidant and antifungal activities of the essential oil from Vietnamese Ocimum tenuiflorum L.leaves 越南天竺葵叶精油的化学成分、抗氧化和抗真菌活性
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).69-75
Thi-Hoan Luong, Huu-Khanh-Tan Tran, Woo-Jin Jung, Van-Viet Nguyen, Dang-Minh-Chanh Nguyen
In this study, the authors aim to determine the chemical compositions of the essential oil from Ocimum tenuiflorumleaves and to evaluate its antioxidant and antifungal activities. The essential oil used in this research, extracted by hydrodistillation, was chemically profiled using gas chromatography/mass spectrometry (GC/MS) analysis. Methyl eugenol (46.07%), caryophyllene (15.65%), eugenol (11.83%), β-elemene (4.33%), β-copaene (4.18%), caryophyllene oxide (3.18%), and α-copaene (1.95%) were identified as major components of the essential oil. The results indicated that the essential oil of O. tenuiflorum leaves possessed relatively high 2,2-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging activities with IC50 values of 53.5 and 55.1 μg/ml, respectively, compared with 67.2 and 63.2 μg/ml, respectively, for the positive control. The reducing powers of O. tenuiflorum essential oil and butylated hydroxytoluene (BHT) at a concentration of 200 μg/ml were 0.95 and 0.73, respectively. Additionally, the essential oil of O. tenuiflorum at a concentration of 200 μg/ml strongly inhibited the mycelial growth of Rhizoctonia solani.
在这项研究中,作者旨在确定从欧加木(Ocimum tenuiflorum)叶中提取的精油的化学成分,并评估其抗氧化和抗真菌活性。本研究中使用的精油是通过水蒸馏法提取的,使用气相色谱/质谱(GC/MS)分析法对其进行了化学分析。经鉴定,甲基丁香酚(46.07%)、叶黄素(15.65%)、丁香酚(11.83%)、β-榄香烯(4.33%)、β-罂粟烯(4.18%)、氧化叶黄素(3.18%)和α-罂粟烯(1.95%)是精油的主要成分。结果表明,O. tenuiflorum 叶精油具有较高的 2,2-二苯基-2-苦基肼(DPPH)和 2,2'-偶氮二-(3-乙基苯并噻唑啉-6-磺酸)(ABTS)自由基清除活性,IC50 值分别为 53.5 和 55.1 μg/ml,而阳性对照的 IC50 值分别为 67.2 和 63.2 μg/ml。在浓度为 200 μg/ml 时,O. tenuiflorum 精油和丁基羟基甲苯(BHT)的还原力分别为 0.95 和 0.73。此外,浓度为 200 μg/ml 的O. tenuiflorum 精油能强烈抑制根瘤菌(Rhizoctonia solani)的菌丝生长。
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引用次数: 0
Physico-chemical analysis in ternary organic mixtures at various temperatures with an acoustical approach 用声学方法对不同温度下的三元有机混合物进行物理化学分析
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).03-09
S. Nithiyanantham, V. Vanathi, S. Mullainathan, S. Mahalakshmi, L. Palaniappan
Thermo-dynamical analyses of organic mixtures are essential across industries. Ultrasonic sound velocity (U) measurements in the ternary organic mixtures of Toluene, Chloroform, and Cyclohexane have been conducted between 303.15, 308.15 and 313.15 K. The experimental/derived data were utilised to compute deviations for their excess values such as adiabatic compressibility (βE), free length (LfE), free volume (VfE), impedance (ZE), internal pressure (πiE) and enthalpy (HE) to investigate and confirm the types of interactions. Using these derived parameters, excess parameters were calculated to further reaffirm the type, strength, magnitude, and potential interactions such as complex formation, dipole-dipole, and dispersive types. Moreover, both ideal and non-ideal behaviours were analysed. The ultrasonic velocity data were validated against some contemporary and well-known models like Namoto’s relation (NR), Ideal mixture relation (IMR), Impedance dependence relation (IDR), Collision factor theory (CFT) and Nutch-Kunkies (NK) theorem. From the IMR and IDR are gives well approach to experimental one. And a comparative study of these models was conducted to ascertain the possible types of interactions within the mixtures through their molecular interaction parameter, percentage deviation, standard percentage error deviation.
有机混合物的热动力学分析对各行各业都至关重要。在 303.15、308.15 和 313.15 K 之间对甲苯、氯仿和环己烷三元有机混合物进行了超声波声速 (U) 测量。实验/推导数据被用来计算其超常值的偏差,如绝热可压缩性 (βE)、自由长度 (LfE)、自由体积 (VfE)、阻抗 (ZE)、内压 (πiE) 和焓 (HE),以研究和确认相互作用的类型。利用这些推导出的参数,还计算了多余参数,以进一步确认相互作用的类型、强度、大小和潜在的相互作用,如复合物形成、偶极子-偶极子和分散类型。此外,还分析了理想和非理想行为。超声波速度数据根据一些当代著名的模型进行了验证,如 Namoto 关系(NR)、理想混合物关系(IMR)、阻抗依赖关系(IDR)、碰撞因子理论(CFT)和 Nutch-Kunkies 理论(NK)。从 IMR 和 IDR 可以很好地接近实验模型。我们对这些模型进行了比较研究,通过它们的分子相互作用参数、百分比偏差、标准百分比误差偏差来确定混合物中可能存在的相互作用类型。
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引用次数: 0
Comparing the efficacy of online vs. offline methods in modulating emotional responses through mental stress tasks 比较在线和离线方法在通过心理压力任务调节情绪反应方面的功效
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).107-113
Luan Van Tran, Anh Phuc Hoang Le, Thao Mai Le, My Thi Tra Nguyen, Quang Lam Nguyen, Huong Thi Thanh Ha
Emotion regulation and stress represent two complex, intertwined processes. Yet, there is a paucity of studies examining the effect of stress on emotional regulation among Vietnamese students, specifically the influence of online and offline experimental conditions. This study investigates these dynamics by subjective assessment of the emotional responses of the subjects participating in this study. The research was structured in three primary phases: preliminary, online (conducted via the Internet), and offline (conducted in person) experiments. The preliminary phase (N=16) aimed to validate the appropriateness of the International Affective Picture System (IAPS) picture library and emotional stimulation videos from previous studies. Participants in the online (N=30) and offline (N=45) experiments were divided into control and stress groups, distinguished by the difficulty and urgency of the mental arithmetic task (MAT). Participants were then asked to view photos and videos and to rate their subjective feelings using the Self-assessment Manikin (SAM). The online experimental session revealed that subjects under acute stress exhibited heightened sensitivity, as indicated by increased valence scores in the positive and neutral groups, and decreased scores for negative imagery (Positive: MD=0.292, p=0.0113; Neutral: MD=0.245, p=0.001; Negative: MD=-0.435, p<0.0001). An increase in arousal scores in the stress group was also observed for positive (p<0.0001) and neutral sets (p<0.0001). However, these findings were not replicated in the offline experiment session. In conclusion, the IAPS pictures have proven suitable for emotional studies among Vietnamese students.
情绪调节和压力是两个复杂而又相互交织的过程。然而,很少有研究探讨压力对越南学生情绪调节的影响,特别是在线和离线实验条件的影响。本研究通过对参与本研究的受试者的情绪反应进行主观评估来研究这些动态变化。研究分为三个主要阶段:初步、在线(通过互联网进行)和离线(亲自进行)实验。初步阶段(N=16)旨在验证国际情感图片系统(IAPS)图片库和以往研究中的情感刺激视频是否合适。在线(30 人)和离线(45 人)实验的参与者被分为对照组和压力组,根据心算任务(MAT)的难度和紧迫性进行区分。然后,受试者被要求观看照片和视频,并使用自我评估人体模型(SAM)对自己的主观感受进行评分。在线实验显示,处于急性压力下的受试者表现出更高的敏感性,这表现在积极组和中性组的情绪分数增加,而消极意象的分数减少(积极组:MD=0.292,P=0.01):MD=0.292,p=0.0113;Neutral:MD=0.245,p=0.001;Negative:MD=-0.435,p<0.0001)。在积极组(p<0.0001)和中性组(p<0.0001),也观察到压力组的唤醒分数有所增加。然而,这些结果在离线实验环节中没有得到重复。总之,事实证明 IAPS 图片适用于越南学生的情绪研究。
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引用次数: 0
Molecular docking and molecular dynamics simulation revealed potential compounds in Salvia miltiorrhiza for inhibiting enzymes and receptors in Alzheimer’s disease 分子对接和分子动力学模拟揭示了丹参中抑制阿尔茨海默病酶和受体的潜在化合物
Pub Date : 2024-06-15 DOI: 10.31276/vjste.66(2).89-100
Tung Bui Thanh, Trang Vu Dai, Huong Le Thi
Alzheimer’s disease is an age-related neurodegenerative disorder that leads to cognitive and functional decline. Potential target proteins for managing Alzheimer’s disease include Acetylcholinesterase (AChE), Butyrylcholinesterase (BuChE), Beta-secretase cleavage enzyme (BACE1) and N-methyl-D-aspartate (NMDA) receptors. In this study, we conducted in silico evaluations of the inhibitory effects of Salvia miltiorrhiza’s compounds on AChE, BuChE, BACE1, and NMDA receptors. The Lipinski's rule of five was employed to compare phytochemicals with drug-like and non-drug-like properties. Based on previous publications, we compiled a list of 30 compounds from S.miltiorrhiza with potential for improving Alzheimer’s disease. Among these 30 compounds, six natural compounds exhibited potential inhibition of all four target proteins. Five of these six compounds, namely Tanshinone I, Tanshinone IIA, Isotanshinone I, Dihydroisotanshinone I, and Dihydroisotanshinone II, possessed drug-like properties, good absorption potential, and the ability to cross the blood-brain barrier. In conclusion, these five compounds show the highest potential as future drug candidates for the treatment of Alzheimer’s disease.
阿尔茨海默病是一种与年龄有关的神经退行性疾病,会导致认知和功能衰退。控制阿尔茨海默病的潜在靶蛋白包括乙酰胆碱酯酶(AChE)、丁酰胆碱酯酶(BuChE)、β-分泌酶裂解酶(BACE1)和 N-甲基-D-天冬氨酸(NMDA)受体。在本研究中,我们对丹参化合物对 AChE、BuChE、BACE1 和 NMDA 受体的抑制作用进行了硅学评估。我们采用利宾斯基五分法来比较具有类药物特性和非类药物特性的植物化学物质。根据之前发表的文章,我们从 S.miltiorrhiza 中整理出了 30 种具有改善阿尔茨海默病潜力的化合物。在这 30 种化合物中,有 6 种天然化合物具有抑制所有四种目标蛋白的潜力。这六个化合物中的五个,即丹参酮 I、丹参酮 IIA、异丹参酮 I、二氢异丹参酮 I 和二氢异丹酮 II,具有类似药物的性质、良好的吸收潜力和穿越血脑屏障的能力。总之,这五种化合物最有可能成为未来治疗阿尔茨海默病的候选药物。
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引用次数: 0
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Ministry of Science and Technology, Vietnam
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