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1.
Deposition of amyloid β (Aβ) fibrils in the brain is a key pathologic hallmark of Alzheimer’s disease. A class of polyphenolic biflavonoids is known to have anti-amyloidogenic effects by inhibiting aggregation of Aβ and promoting disaggregation of Aβ fibrils. In the present study, we further sought to investigate the structural basis of the Aβ disaggregating activity of biflavonoids and their interactions at the atomic level. A thioflavin T (ThT) fluorescence assay revealed that amentoflavone-type biflavonoids promote disaggregation of Aβ fibrils with varying potency due to specific structural differences. The computational analysis herein provides the first atomistic details for the mechanism of Aβ disaggregation by biflavonoids. Molecular docking analysis showed that biflavonoids preferentially bind to the aromatic-rich, partially ordered N-termini of Aβ fibril via the π–π interactions. Moreover, docking scores correlate well with the ThT EC50 values. Molecular dynamic simulations revealed that biflavonoids decrease the content of β-sheet in Aβ fibril in a structure-dependent manner. Hydrogen bond analysis further supported that the substitution of hydroxyl groups capable of hydrogen bond formation at two positions on the biflavonoid scaffold leads to significantly disaggregation of Aβ fibrils. Taken together, our data indicate that biflavonoids promote disaggregation of Aβ fibrils due to their ability to disrupt the fibril structure, suggesting biflavonoids as a lead class of compounds to develop a therapeutic agent for Alzheimer’s disease.  相似文献   
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角接触球轴承在运行过程中的润滑状况至关重要,润滑油直接影响滚动轴承的接触状态。为分析角接触球轴承的润滑状况以及考虑润滑时轴承的机械特性,基于有限元和晶格玻尔兹曼方法,建立了双向流固耦合轴承仿真模型,对角接触球轴承进行动力学有限元仿真和润滑流体仿真,并与轴承拟静力学理论计算结果进行对比,验证模型的准确性。分析结果表明,保持架与滚珠接触并撞击,在轴承腔内油膜压力最大,滚珠与内圈、外圈滚道接触区分别为第二、第三大油膜压力区。润滑油受滚珠公转影响,沿着滚珠转动方向流动,实现对滚珠与内圈、外圈和保持架之间的润滑。滚珠运动和最大接触应力仿真结果与轴承拟静力学理论求解结果一致,即流固耦合仿真模型计算轴承机械特性具有较高的准确性。  相似文献   
4.
The Gli-B1-encoded γ-gliadins and non-coding γ-gliadin DNA sequences for 15 different alleles of common wheat have been compared using seven tests: electrophoretic mobility (EM) and molecular weight (MW) of the encoded major γ-gliadin, restriction fragment length polymorphism patterns (RFLPs) (three different markers), Gli-B1-γ-gliadin-pseudogene known SNP markers (Single nucleotide polymorphisms) and sequencing the pseudogene GAG56B. It was discovered that encoded γ-gliadins, with contrasting EM, had similar MWs. However, seven allelic variants (designated from I to VII) differed among them in the other six tests: I (alleles Gli-B1i, k, m, o), II (Gli-B1n, q, s), III (Gli-B1b), IV (Gli-B1e, f, g), V (Gli-B1h), VI (Gli-B1d) and VII (Gli-B1a). Allele Gli-B1c (variant VIII) was identical to the alleles from group IV in four of the tests. Some tests might show a fine difference between alleles belonging to the same variant. Our results attest in favor of the independent origin of at least seven variants at the Gli-B1 locus that might originate from deeply diverged genotypes of the donor(s) of the B genome in hexaploid wheat and therefore might be called “heteroallelic”. The donor’s particularities at the Gli-B1 locus might be conserved since that time and decisively contribute to the current high genetic diversity of common wheat.  相似文献   
5.
In this study, we investigate the immunomodulatory effects of a novel antimicrobial peptide, YD1, isolated from Kimchi, in both in vitro and in vivo models. We establish that YD1 exerts its anti-inflammatory effects via up-regulation of the Nrf2 pathway, resulting in the production of HO-1, which suppresses activation of the NF-κB pathway, including the subsequent proinflammatory cytokines IL-1β, IL-6, and TNF-α. We also found that YD1 robustly suppresses nitric oxide (NO) and prostaglandin E2 (PGE2) production by down-regulating the expression of the upstream genes, iNOS and COX-2, acting as a strong antioxidant. Collectively, YD1 exhibits vigorous anti-inflammatory and antioxidant activity, presenting it as an interesting potential therapeutic agent.  相似文献   
6.
Owing to the prohibition of cosmetic animal testing, various attempts have recently been made using skin-on-a-chip (SOC) technology as a replacement for animal testing. Previously, we reported the development of a pumpless SOC capable of drug testing with a simple drive using the principle that the medium flows along the channel by gravity when the chip is tilted using a microfluidic channel. In this study, using pumpless SOC, instead of drug testing at the single-cell level, we evaluated the efficacy of α-lipoic acid (ALA), which is known as an anti-aging substance in skin equivalents, for skin tissue and epidermal structure formation. The expression of proteins and changes in genotyping were compared and evaluated. Hematoxylin and eosin staining for histological analysis showed a difference in the activity of fibroblasts in the dermis layer with respect to the presence or absence of ALA. We observed that the epidermis layer became increasingly prominent as the culture period was extended by treatment with 10 μM ALA. The expression of epidermal structural proteins of filaggrin, involucrin, keratin 10, and collagen IV increased because of the effect of ALA. Changes in the epidermis layer were noticeable after the ALA treatment. As a result of aging, damage to the skin-barrier function and structural integrity is reduced, indicating that ALA has an anti-aging effect. We performed a gene analysis of filaggrin, involucrin, keratin 10, integrin, and collagen I genes in ALA-treated human skin equivalents, which indicated an increase in filaggrin gene expression after ALA treatment. These results indicate that pumpless SOC can be used as an in vitro skin model similar to human skin, protein and gene expression can be analyzed, and it can be used for functional drug tests of cosmetic materials in the future. This technology is expected to contribute to the development of skin disease models.  相似文献   
7.
张弛  李浩  胡海涛  朱翀  张玉莹  南国鹏  舒悦 《化工学报》2021,72(Z1):430-436
针对飞行器轴承信号单一且噪声多、需要针对性特征以及需要高可解释性的问题,开发了涵盖具有自适应噪声的完全集合经验模态分解(CEEMDAN)、自动特征工程以及随机森林的故障诊断模型,模型核心为自动进行特征生成以及提取的特征工程。通过该特征工程能够根据不同对象的信号差异,自动提取出不同对象的有效特征,具备对象间的通用性,且该特征工程可根据样本量的不同调整有效特征的数量,丰富特征空间,具备灵活的可扩展性。验证表明,该涵盖自动特征工程的模型的故障分类准确率为95.32%,可较好地在大样本量下区分压缩机轴承上的不同故障。  相似文献   
8.
刘璐  庞杰 《粮油食品科技》2021,29(2):129-134
凝胶是一种性质介于固体和液体之间的特殊分散体系,魔芋葡甘聚糖(KGM)凝胶稳定性差、强度低,物理共混能方便、快捷地改善其凝胶性质。主要综述KGM复合凝胶的网络结构变化,并介绍不同复合凝胶在食品、医药、材料工程等领域的应用。分析表明,KGM复合凝胶网络能通过氢键、席夫碱反应、形成多重网络结构和填充的方式改善其凝胶特性。  相似文献   
9.
碳达峰、碳中和目标是党中央国务院审时度势提出的重大战略决策,是我国能源行业革命性的变革,将对全球能源供需格局产生深远影响,为我国能源矿产未来发展指明了方向。我国作为世界最大的能源生产国和消费国,煤炭资源丰富,石油、天然气、铀等能源矿产自主供应能力不足,未来较长时间内能源矿产在我国一次能源消费中仍居主导地位。受资源禀赋、工业化发展阶段和以煤为主的能源消费结构等因素影响,我国承诺实现碳中和的目标和发达国家相比面临的挑战更加艰巨。本文通过梳理我国能源矿产发展现状,碳达峰、碳中和目标背景下初步预测2030年前我国化石能源消费将达到峰值45亿t标准煤左右,2060年非化石能源消费将占我国一次能源消费的85%左右。通过展望煤炭、石油、天然气等能源矿产的发展方向,从三个方面提出了相关政策建议:一是加强国内能源矿产发展利用的顶层设计;二是大力提升国内油气资源自主供应能力;三是处理好碳达峰、碳中和目标约束与能源安全保障的关系。  相似文献   
10.
为延长带鱼鱼丸保质期,以带鱼鱼丸为原料,分别在250、300、350 MPa压力下处理5 min,以冷藏期间鱼丸菌落总数、总挥发性盐基氮(total volatile base nitrogen,TVB-N)含量、pH值为指标,并结合感官评价、色值、凝胶强度及质地剖面分析,探究超高压处理对冷藏带鱼鱼丸保鲜效果的影响。结果表明:超高压处理可显著降低贮藏期内鱼丸菌落总数、TVB-N含量,延缓pH值的增加;超高压处理对鱼丸色泽无负面影响,同时能较好保持鱼丸冷藏期间感官特性、色值、凝胶强度、硬度及弹性。对照组和超高压组鱼丸的菌落总数分别在冷藏的第21天和第56天超出105 CFU/g;随冷藏时间延长,对照组鱼丸感官评分明显下降,贮藏14 d后产生异味,第21天时感官已不可接受;超高压组鱼丸感官评分在贮藏35 d内均无明显变化,其中300 MPa处理5 min组在冷藏49 d后感官评分仍在5 分以上,但第56天时感官不可接受。综合考虑,对带鱼鱼丸进行300 MPa超高压处理5 min,可延长其冷藏货架期约35 d。该结果可以为超高压技术在鱼糜制品保鲜中的应用提供依据。  相似文献   
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