Structure characteristics

  • 文章类型: Journal Article
    限速阶段是气化过程中的炭反应性,这可能受其物理化学结构特征的影响。在这项研究中,原料份额的影响,稻草(RS)和聚乙烯(PE),研究了焦炭的理化性质和气化反应性,并讨论了它们之间的关系。使用热分析仪通过等温实验研究了焦炭的气化反应性。结果表明,添加PE改善了从与PE共热解RS获得的焦炭的比表面积(SSA)和孔体积(Vp)。当PE含量为60wt%时,焦炭的SSA增加了1.31倍,与RSchar相比。共热解炭样品的有序度和气化反应性随着PE含量超过40wt%而增加。共气化早期的炭反应性主要取决于碳质和孔结构的有序度。后期的焦炭反应性受这两个因素的影响,二氧化硅含量会抑制焦炭的共气化反应性。
    The rate limiting stage is char reactivity during gasification that can be influenced by its physicochemical structural characteristics. In this study, the effects of feedstock share, rice straw (RS) and polyethylene (PE), on the physicochemical properties and gasification reactivity of chars were investigated and their relationships were discussed. The char gasification reactivity was investigated via isothermal experiments using a thermal analyzer. The results indicated that the PE addition improved the specific surface area (SSA) and pore volume (Vp) of the char obtained from co-pyrolysis RS with PE. The SSA of the char increased by 1.31 times when the PE content was 60 wt%, compared with that of RS char. The order degree and gasification reactivity of the co-pyrolysis char samples increased with increasing PE content beyond 40 wt%. The char reactivity in the early stage of co-gasification was primarily determined by the order degree of carbonaceous and pore structure. The char reactivity in the later stage was influenced by these two factors and the silicon dioxide content could inhibit the char co-gasification reactivity.
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  • 文章类型: Journal Article
    科技专员制度(SCS)是中国政府利用科学技术加强农业部门的探索性努力的结果。社会网络分析(SNA)和机器学习(ML)技术使得利用群体类型和结构特征等指标来评估中国SCS的服务绩效成为可能。在这项研究中,采用SNA和聚类算法对科技人员的服务组类型进行分类。通过比较不同分类算法预测聚类结果的准确性,最后选择LightGBM算法来确定科技委员的聚类特征,并建立可解释的ML模型。然后,利用SHAP算法分析影响服务性能的影响因素。结果表明,科技委员的服务形式是以群体为导向的,这种群体类型包括密切合作的年轻委员小组,更多的中青年委员,一小群中老年委员密切配合,以及极有影响力的委员的孤立点。此外,虽然组大小不是专员平均绩效的决定因素,发现群体结构和协调能力更为关键。此外,虽然不同类型的服务性能的差异是由各种因素引起的,但是良好的群体结构和广泛的社会联系对于高服务绩效至关重要。
    The Sci-Tech Commissioner System (SCS) is a result of exploratory efforts by the Chinese government to use science and technology to strengthen the agricultural sector. Social network analysis (SNA) and machine learning (ML) techniques make it feasible to assess the service performance in China\'s SCS by using indicators such as group types and structure features. In this study, SNA and a clustering algorithm were employed to categorize service group types of sci-tech commissioners. By comparing the accuracy of different classification algorithms in predicting the clustering results, LightGBM algorithm was finally select to determine the clustering features of sci-tech commissioners and establish an interpretable ML model. Then, the SHAP was used to algorithm to analyze influences affecting service performance. Results show that the service forms of sci-tech commissioners are group-oriented, and that group types include small groups of young commissioners with close cooperation, larger groups of young and middle-aged commissioners, small groups of middle-aged and old commissioners with close cooperation, and isolated points of highly-influential commissioners. Furthermore, while group size is not the determinant of a commissioner\'s average performance, group structure and coordination ability were found to be more critical. Moreover, while differences in distinct types of service performance are caused by various factors, but good group structures and extensive social contacts are essential for high service performance.
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  • 文章类型: Journal Article
    在太平洋鳕鱼骨中发现了钙螯合肽,但它们的结合结构和性质尚未阐明。通过羟基磷灰石亲和色谱(HAC)分离新型钙结合肽,并通过等温滴定量热法(ITC)研究了它们的结合结构和性能,多光谱技术,和质谱。基于多重净化,太平洋鳕鱼骨肽(PBPs)的钙结合能力(CBC)从1.71±0.15μg/mg增加到7.94±1.56μg/mg。分子量为1-2kDa的肽与CBC密切相关。与钙结合后,肽的二级结构从无规卷曲过渡到β折叠,导致松散和多孔的微观结构。氢键,静电相互作用,和疏水相互作用有助于肽-钙复合物的形成。F21含有42个肽,带有重复的“GE”图案。差异结构分析为靶向制备高CBC多肽提供了理论依据。
    Calcium-chelating peptides were found in Pacific cod bone, but their binding structure and properties have not been elucidated. Novel calcium-binding peptides were isolated by hydroxyapatite affinity chromatography (HAC), and their binding structure and properties were investigated by isothermal titration calorimetry (ITC), multispectral techniques, and mass spectrometry. Based on multiple purifications, the calcium binding capacity (CBC) of Pacific cod bone peptides (PBPs) was increased from 1.71 ± 0.15 μg/mg to 7.94 ± 1.56 μg/mg. Peptides with a molecular weight of 1-2 kDa are closely correlated with CBC. After binding to calcium, the secondary structure of peptides transitioned from random coil to β-sheet, resulting in a loose and porous microstructure. Hydrogen bonds, electrostatic interaction, and hydrophobic interaction contribute to the formation of peptide‑calcium complexes. The F21 contained 42 peptides, with repeated \"GE\" motif. Differential structure analysis provides a theoretical basis for the targeted preparation of high CBC peptides.
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  • 文章类型: Journal Article
    片剂制造过程中的穿孔粘附是制药工业遇到的许多活性药物成分(API)的普遍问题。富马酸替诺福韦阿米非胺(TMF),一种治疗乙型肝炎的重量级药物,由于其在片剂压缩过程中容易打孔粘附而被选择为模型。在这项研究中,通过调查水晶习性来探索粘附的原因,赋形剂和结构特征。通过对粉末样品的直接压缩实验和晶体表面的分析,可以直观地表示三种晶体习性的粘附差异。赋形剂在降低粘连的可能性中起直接作用,粘附的程度可以通过测量片剂的拉伸强度来评估。此外,利用可塑性指数从理论上分析了四种赋形剂的潜在增强作用.这些实验结果表明,块状晶体具有优异的抗粘附能力,合适的赋形剂可以显着改善TMF的粘附情况。最终,通过计算计算,对冲头粘连现象进行了额外的检查,重点研究了TMF分子的力学特性和分子间的相互作用。实验和模拟计算相结合的策略对研究药物生产具有更广泛的意义。
    Punch sticking during tablet manufacturing is a prevalent issue for many active pharmaceutical ingredients (APIs) encountered by the pharmaceutical industry. Tenofovir amibufenamide fumarate (TMF), a heavyweight drug for the treatment of hepatitis B, was selected as a model drug due to its tendency to punch sticking during tablet compression. In this study, the cause of sticking was explored by investigating crystal habits, excipients and structure characteristics. The difference in sticking of three crystal habits can be visually represented through direct compression experiments on powdered samples and analysis of crystal surfaces. The excipients play a direct role in decreasing the probability of sticking, and the extent of sticking can be assessed by measuring the tensile strength of the tablet. Additionally, the plasticity index was utilized to theoretically analyze the potential enhancements of four excipients. These experimental results indicate that the block-shaped crystals have superior ability of anti-sticking and that suitable excipients can significantly improve the sticking situation of TMF. Ultimately, the phenomenon of punch sticking was additionally examined through computational calculations, focusing on the mechanical characteristics of TMF molecules and intermolecular interactions. The strategy of combining experiments and simulation calculations has broader significance for the study of drug production.
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  • 文章类型: Journal Article
    桔梗(P.grandiflorus),一种既用于医药又用于食品的传统中草药,有治疗呼吸道感染的悠久历史,支气管炎,肺炎,和其他肺部相关疾病。的治疗效果是由于其化学成分,包括多糖。在这些组件中,桔梗多糖(PGP)是公认的最重要和最丰富的活性成分之一,表现出各种生物活性,如益生元,抗氧化剂,抗病毒,抗癌,抗血管生成,和免疫调节特性。结合中医原理,承运人概念,和现代靶向药物递送技术,PGP可以影响其他药物的靶位点和治疗效果,同时也可以作为靶向和精确治疗的药物载体。因此,必须对提取进行全面审查,分离,净化,物理化学性质,PGP的生物学活性。在未来,通过整合新概念,技术,和过程,可为PGP的全面发展提供参考和指导。这将有助于P.grandiflorus在各个领域的进步,如制药,健康产品,和食物。
    Platycodon grandiflorus (P. grandiflorus), a traditional Chinese medicinal herb used for both medicine and food, has a long history of treating respiratory infections, bronchitis, pneumonia, and other lung-related diseases. The therapeutic effects of P. grandiflorus are attributed to its chemical components, including polysaccharides. Among these components, Platycodon grandiflorus polysaccharides (PGP) are recognized as one of the most important and abundant active ingredients, exhibiting various biological activities such as prebiotic, antioxidant, antiviral, anticancer, antiangiogenic, and immune regulatory properties. Incorporating the principles of traditional Chinese medicine, carrier concepts, and modern targeted drug delivery technologies, PGP can influence the target sites and therapeutic effects of other drugs while also serving as a drug carrier for targeted and precise treatments. Therefore, it is essential to provide a comprehensive review of the extraction, separation, purification, physicochemical properties, and biological activities of PGP. In the future, by integrating new concepts, technologies, and processes, further references and guidance can be provided for the comprehensive development of PGP. This will contribute to the advancement of P. grandiflorus in various fields such as pharmaceuticals, health products, and food.
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  • 文章类型: Journal Article
    背景:花椒种子,作为一种低成本且易于获取的植物蛋白资源,在食品工业中具有良好的潜力。但花椒籽蛋白质及其水解产物的研究较少,未得到充分利用。本研究旨在研究其结构,花椒籽蛋白(ZSP)水解产物的理化和生物活性,alcalase,中和酶,胰蛋白酶和胃蛋白酶,分别。
    结果:五种酶的水解降低了ZSP的平均粒径和分子量,但增加了随机线圈。由胃蛋白酶制备的ZSP水解物水解度最高(24.07%),分子量最小(<13kDa),平均粒径(129.80nm),溶解度最高(98.9%)。虽然Alcalase制备的ZSP水解物具有最高的表面疏水性,发泡能力(88.89%),以及最低的泡沫稳定性(45.00%)。此外,Alcalase制备的ZSP水解物表现出最佳的羟自由基清除活性(IC501.94mgmL-1)和Fe2螯合活性(IC500.61mgmL-1)。此外,胃蛋白酶制备的ZSP水解物显示出最高的血管紧张素转换酶(ACE)抑制活性,IC50为0.54mgmL-1。
    结论:这些数据表明酶水解改善了ZSP的理化性质,ZSP酶解产物表现出显著的生物活性。这些结果为ZSP酶水解产物在食品或医药工业中作为抗氧化剂和抗高血压剂的应用提供了验证。本文受版权保护。保留所有权利。
    BACKGROUND: Zanthoxylum seed, as a low-cost and easily accessible plant protein resource, has good potential in the food industry. But protein and its hydrolysates from Zanthoxylum seed are underutilized due to the dearth of studies on them. This study aimed to investigate the structure and physicochemical and biological activities of Zanthoxylum seed protein (ZSP) hydrolysates prepared using Protamex®, Alcalase®, Neutrase®, trypsin, or pepsin.
    RESULTS: Hydrolysis using each of the five enzymes diminished average particle size and molecular weight of ZSP but increased random coil content. ZSP hydrolysate prepared using pepsin had the highest degree of hydrolysis (24.07%) and the smallest molecular weight (<13 kDa) and average particle size (129.80 nm) with the highest solubility (98.9%). In contrast, ZSP hydrolysate prepared using Alcalase had the highest surface hydrophobicity and foaming capacity (88.89%), as well as the lowest foam stability (45.00%). Moreover, ZSP hydrolysate prepared using Alcalase exhibited the best hydroxyl-radical scavenging (half maximal inhibitory concentration (IC50 ) 1.94 mg mL-1 ) and ferrous-ion chelating (IC50 0.61 mg mL-1 ) activities. Additionally, ZSP hydrolysate prepared using pepsin displayed the highest angiotensin-converting enzyme inhibition activity (IC50 0.54 mg mL-1 ).
    CONCLUSIONS: These data showed that enzyme hydrolysis improved the physicochemical properties of ZSP, and enzymatic hydrolysates of ZSP exhibited significant biological activity. These results provided validation for application of ZSP enzymatic hydrolysates as antioxidants and antihypertensive agents in the food or medicinal industries. © 2023 Society of Chemical Industry.
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  • 文章类型: Journal Article
    尽管原肌球蛋白已被确定为南极磷虾的主要过敏原,南极磷虾原肌球蛋白的消化命运及其与致敏性的关系尚不清楚。在这项研究中,通过灌胃和腹腔注射对BALB/c小鼠施用南极磷虾原肌球蛋白,以探讨其致敏和诱导能力。并分析其消化产物的结构变化和耐消化线性表位。用原肌球蛋白灌胃的小鼠表现出更低水平的特异性IgE和IgG1,肥大细胞脱颗粒,血管通透性,和过敏反应症状优于腹腔注射组。这可能是由于大分子聚集体的破坏,三级结构的松散膨胀,α-螺旋完全消失,和原肌球蛋白消化时分子力的显著变化。然而,南极磷虾原肌球蛋白的胃内给药仍然引发强烈的过敏反应,这归因于存在七个消化抗性线性表位(Glu26-His44,Thr111-Arg125,Glu157-Glu164,Glu177-Gly186,Val209-Ile225,Arg244-Arg255和Val261-Ile270)。
    Although tropomyosin has been identified as a major allergen in Antarctic krill, the digestive fate of Antarctic krill tropomyosin and its relationship with allergenicity are unknown. In this study, Antarctic krill tropomyosin was administered to BALB/c mice via both gavage and intraperitoneal injection to explore its sensitizing and eliciting capacity, and its digestion products were analyzed for structural changes and digestion-resistant linear epitopes. Mice gavaged with tropomyosin exhibited lower levels of specific IgE and IgG1, mast cell degranulation, vascular permeability, and anaphylaxis symptoms than those in the intraperitoneal injection group. This may be due to the destruction of macromolecular aggregates, loose expansion of the tertiary structure, complete disappearance of α-helix, and significant changes in molecular force upon the digestion of tropomyosin. Nevertheless, the intragastric administration of Antarctic krill tropomyosin still triggered strong allergic reactions, which was attributed to the existence of seven digestion-resistant linear epitopes (Glu26-His44, Thr111-Arg125, Glu157-Glu164, Glu177-Gly186, Val209-Ile225, Arg244-Arg255, and Val261-Ile270).
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  • 文章类型: Journal Article
    在自然界的低共熔溶剂(NADES)中,通过超声美拉德反应(MR)成功地将中国大葱皮肤胶原蛋白(CGSSC)与葡萄糖(Glu)/木糖(Xy)缀合。超声和还原糖类型对MR产品(MRP)的程度接枝(DG)的影响,以及DG对MRPs结构和功能性质的影响进行了研究。结果表明,超声辅助可以显着增强CGSSC的MR。低分子量还原糖在MR中更具反应性。超声MR显着改变了微观结构,CGSSC的二级和三级结构。此外,MRP的游离巯基含量增加,从而增强表面疏水性,乳化性能和抗氧化活性,与DG呈正相关。这些发现为超声辅助和不同糖类型对MR诱导的胶原蛋白功能特性的影响提供了理论见解。
    Chinese giant salamander skin collagen (CGSSC) was successfully conjugated with glucose (Glu)/xylose (Xy) by ultrasound Maillard reaction (MR) in nature deep eutectic solvents (NADES). The effects of ultrasound and reducing sugar types on the degree graft (DG) of MR products (MRPs), as well as the influence of DG on the structure and functional properties of MRPs were investigated. The results indicated that the ultrasound assisted could markedly enhance the MR of CGSSC, and low molecular weight reducing sugars were more reactive in MR. The ultrasound MR significantly changed the microstructure, secondary and tertiary structures of CGSSC. Moreover, the free sulfhydryl content of MRPs were increased, thus enhancing the surface hydrophobicity, emulsifying properties and antioxidant activity, which were positively correlated with DG. These findings provided theoretical insights into the effects of ultrasound assisted and different sugar types on the functional properties of collagen induced by MR.
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  • 文章类型: Journal Article
    本研究研究了从未成熟柿子(PP-1)和成熟柿子(PP-2)中提取的两种不同分子量柿子果胶的结构和功能特性。对于由葡萄糖组成的PP-1和PP-2,分子量确定为117.8kDa和61.3kDa。鼠李糖,甘露糖,半乳糖,和木糖.AFM结果表明PP-1具有许多线性链,和短链,而短链,分支点,在PP-2中发现了异质团块。乳液表征和储存稳定性实验表明,PP-1比PP-2和市售柑橘果胶具有更稳定的乳化性能。通过肠道菌群对PP-1和PP-2的体外发酵表明,在发酵48h后,PP-1和PP-2组的总SCFA产量高于菊粉组。本研究为柿子果胶的高值化利用提供了有益的信息。
    This study investigated the structural and functional characteristics of two different molecular weight persimmon pectin extracted from unripe persimmon (PP-1) and ripe persimmon (PP-2). The molecular weight was determined as 117.8 kDa and 61.3 kDa for PP-1 and PP-2, which consisting of glucose, rhamnose, mannose, galactose, and xylose. AFM results indicated PP-1 with many linear chains, and short chains in while short chains, branching points, and heterogeneous clumps were found in PP-2.Emulsion characterization and storage stability experiments revealed that PP-1 with more stable emulsifying properties than PP-2 and commercial citrus pectin. In vitro fermentation of PP-1 and PP-2 by gut microbiota indicated that PP-1 and PP-2 groups were higher than inulin group in total SCFAs production after 48 h of fermentation. This study provided useful information for high value utilization of persimmon pectin.
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  • 文章类型: Journal Article
    pH处理显著增强了卵清蛋白(EWP)的功能特性,但对EWP的pH处理与体外消化之间的关系知之甚少。在本文中,我们使用消化动力学和肽组学方法探索了pH处理(pH2,pH2-7,pH12和pH12-7)对卵清蛋白和肽谱的消化率的影响,分开。结果表明,所有的pH处理降低蛋白质在胃期的消化率,而碱性pH(pH12和pH12-7)显示出更高的消化水平和更多的胃肽,更重要的是,比酸处理样品产生更大量的潜在生物活性肽。此外,在pH2下获得的潜在生物活性肽的数量最少,但这可以通过将pH2调回到7来改善。值得注意的是,pH诱导的独特生物活性肽主要与DPPIV抑制剂有关。消化率和肽谱的差异可能归因于蛋白质结构的变化和熔融球的形成。改变消化酶的切割位点。这项工作将为pH诱导的EWP的消化和营养特性提供启发性的见解,以扩大其在食品和医疗保健领域的应用。
    The pH treatment significantly enhanced the functional properties of egg white protein (EWP), but little is known about the relationship between pH treatment and in vitro digestion of EWP. In this paper, we explored the effect of pH treatment (pH 2, pH 2-7, pH 12 and pH 12-7) on the digestibility of egg white protein and peptide profiling using the digestion kinetics and peptidomics methods, separately. The results implied that all pH treatment reduced the protein digestibility in gastric phase, while alkaline pH (pH 12 and pH 12-7) showed greater digestion level and more gastric peptides, and more importantly, produced a greater amount of potentially bioactive peptides than acid treated samples. Besides, the least number of potentially bioactive peptides was obtained at pH 2, but this could be improved by adjusting pH 2 back to 7. Notably, the unique bioactive peptides induced by pH were mainly relevant to DPP IV inhibitor. These differences of digestibility and peptide profiling might be attributed to the change of protein structure and the formation of molten sphere, altering cleavage sites of digestive enzymes. This work would give an enlightening insight into the digestive and nutritional characteristics of the pH-induced EWP to expand their application in the field of food and healthcare.
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