crosslink

Crosslink
  • 文章类型: Journal Article
    水可渗透的中空淀粉颗粒改变了其颗粒状悬浮液的流变行为。然而,它们薄薄的外壳会破裂限制应用。在这项研究中,我们使用a菜淀粉作为构建块(1μm)来制作交联的上部结构。Pickering乳液用作淀粉涂覆液滴的模板。在75°C下加热乳液以诱导聚合物的相互渗透,随后在乙醇中沉淀以引发胶体融合。然后通过三偏磷酸钠使颗粒交联;在通过己烷除去内部模板之后形成中空颗粒。当使用菜籽油时,颗粒在pH11.5时由于股线之间的排斥而破裂。相比之下,棕榈油,在50°C下乳化,冷却后形成刚性芯,将淀粉锁定在表面并保留结构。交联的胶体体较大(89μm),并表现出更高的粘度,和更强的稳定性。使用较高的模板体积产生较大的颗粒(>100μm)。温和离心以收获颗粒保持壳完整。中空结构表现出超过10w/w%的干扰转变,可以用作超增稠剂。这项工作表明,微体系结构在塑造材料功能方面起着关键作用。
    Water-permeable hollow starch particles alter the rheological behavior of their granular suspensions. However, their thin shells can rupture limiting applications. In this study, we used amaranth starch as building blocks (1 μm) to craft a crosslinked superstructure. Pickering emulsions were used as the templates where starch coated the droplets. Emulsions were heated at 75 °C to induce interpenetration of the polymers followed by precipitation in ethanol to trigger colloidal fusion. Particles were then crosslinked by sodium tri-metaphosphate; hollow particles formed after the interior template was removed by hexane. When canola oil was used, the particles ruptured at pH 11.5 due to the repulsion between the strands. In contrast, palm oil, emulsified at 50 °C, formed a rigid core after cooling, locked the starch at the surface and retained the structure. The crosslinked colloidosomes were larger (89 μm) and exhibited higher viscosity, and stronger stability. Larger particles (>100 μm) were produced using higher templating volume. Gentle centrifugation to harvest the particles kept the shells intact. The hollow structure exhibited jamming transition above 10 w/w%, which could serve as a super-thickener. This work demonstrates that microarchitecture plays a critical role in shaping material functionality.
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  • 文章类型: Journal Article
    该研究涉及使用5%-20%范围内的不同量的柠檬酸(CA)制备和表征交联羧甲基纤维素(CMC)膜。w/w,相对于CMC的干重。通过傅里叶变换红外光谱等技术,X射线光电子能谱,羰基含量分析,和凝胶分数测量,确认CMC和CA之间的成功交联。调查包括化学结构分析,物理和光学特性,溶胀行为,水蒸气透过率,水分含量,和表面形态。当与非交联CMC膜相比时,交联CMC膜的耐水性表现出显著的改善。研究结果表明,用10%CA交联的膜表现出作为可食用涂层应用的有利性质。这些透明膜,理想的包装,证明有效保存新鲜香蕉的质量和感官属性,包括颜色保持,最小化的重量损失,通过抑制淀粉体降解减缓成熟,并增强了储存期间的坚固性。
    The study involves the preparation and characterization of crosslinked-carboxymethyl cellulose (CMC) films using varying amounts of citric acid (CA) within the range 5 %-20 %, w/w, relative to the dry weight of CMC. Through techniques such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, carbonyl content analysis, and gel fraction measurements, the successful crosslinking between CMC and CA is confirmed. The investigation includes an analysis of chemical structure, physical and optical characteristics, swelling behavior, water vapor transmission rate, moisture content, and surface morphologies. The water resistance of the cross-linked CMC films exhibited a significant improvement when compared to the non-crosslinked CMC film. The findings indicated that films crosslinked with 10 % CA demonstrated favorable properties for application as edible coatings. These transparent films, ideal for packaging, prove effective in preserving the quality and sensory attributes of fresh bananas, including color retention, minimized weight loss, slowed ripening through inhibiting amyloplast degradation, and enhanced firmness during storage.
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  • 文章类型: Journal Article
    阿魏酸(FA),一种集中在麦麸中的植物化学物质,阿拉伯木聚糖(AX)的结构特征和小麦面团的流变特性。这项研究调查了FA和二阿魏酸的动态变化,与AX分子量密切相关,在面包制作过程中。FA主要以紧密结合的状态存在于阿拉伯木聚糖基质中,在初始发酵阶段观察到游离FA含量大幅增加。此外,这项研究确定了四种特定的小麦衍生的二阿魏酸:8-5'-DFA,5-5'-DFA,8-O-4\'-DFA,和8-5'-DFA(苯并呋喃形式),在整个面包制作过程中跟踪它们的变化。在早期发酵阶段二阿魏酸水平的显著上升表明阿魏酸部分的裂解可能不是促成AX分子量降低的主要因素。未来对FA和二阿魏酸对阿拉伯木聚糖和小麦面团特性的影响的研究有望增强对面包制作过程复杂性的了解。
    Ferulic acid (FA), a phytochemical concentrated in wheat bran, influences structural characteristics of arabinoxylan (AX) and rheological properties of wheat dough. This study investigates the dynamic changes in FA and diferulic acids, closely associated with AX molecular weight, during the breadmaking process. FA predominantly exists in a tightly bound state within the arabinoxylan matrix, with a substantial increase in free FA content observed during the initial fermentation phase. Furthermore, this research identified four specific wheat-derived diferulic acids: 8-5\'-DFA, 5-5\'-DFA, 8-O-4\'-DFA, and 8-5\'-DFA (benzofuran form), tracking their variations throughout breadmaking. The notable upsurge in diferulic acid levels in the early fermentation stages suggests that the cleavage of ferulic acid moieties may not be the primary factor contributing to the reduction in AX molecular weight. Future investigations into the effects of FA and diferulic acids on arabinoxylan and wheat dough properties promise to enhance understanding of the intricacies of the breadmaking process.
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  • 文章类型: Journal Article
    壳聚糖,源自几丁质的脱乙酰化,是地球上丰富的天然生物聚合物。壳聚糖及其衍生物因其独特的分子结构和优异的生物活性而成为有前途的生物材料。壳聚糖的反应性官能团如氨基和羟基在促进三维水凝胶的合成中起着至关重要的作用。壳聚糖基水凝胶已广泛应用于医疗领域,Pharmaceutical,和环境领域多年。如今,壳聚糖基水凝胶已在食品工业中广泛的应用,如食品传感器,染料吸附剂和营养载体。在这次审查中,给出了最近开发的壳聚糖基水凝胶的制备方法,系统地介绍了壳聚糖基水凝胶的生物活性。此外,食物传感器的最新进展,包装,染料吸附剂,并对营养载体进行了讨论。最后,讨论了壳聚糖基水凝胶未来发展面临的挑战和前景。
    Chitosan, derived from the deacetylation of chitin, is an abundant natural biopolymer on earth. Chitosan and its derivatives have become promising biological materials because of their unique molecular structure and excellent biological activities. The reactive functional groups of chitosan such as the amino and hydroxyl groups play a crucial role in facilitating the synthesis of three-dimensional hydrogel. Chitosan-based hydrogels have been widely used in medical, pharmaceutical, and environmental fields for years. Nowadays, chitosan-based hydrogels have been found in a wide range of applications in the food industry such as food sensors, dye adsorbents and nutrient carriers. In this review, recently developed methods for the preparation of chitosan-based hydrogels were given, and the biological activities of chitosan-based hydrogels were systematically introduced. Additionally, the recent progress in food sensors, packaging, dye adsorbents, and nutrient carriers was discussed. Finally, the challenges and prospects for the future development of chitosan-based hydrogels were discussed.
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  • 文章类型: Journal Article
    聚乙烯(PE)的交联行为决定了其出色的性能和应用。在这项研究中,通过模型模拟和流变方法研究了不同PE树脂的交联行为。具体来说,建立了PE树脂“S”模型的数学方程。根据这个等式,发现高密度聚乙烯(HDPE)的最佳最大凝胶含量约为85%。此外,不同PE树脂的最大交联度在很大程度上取决于其密度和分子量。PE树脂中交联前的熔体粘度受熔体指数的高度影响。较高的熔融指数导致较低的储能模量,在加工过程中改善熔融加工性。此外,聚乙烯树脂的交联速率受过氧化物浓度的强烈影响,独立的PE树脂结构。对于高分子量和低密度PE树脂,它们表现出降低的ti值,增加A0值,并降低k6值。然而,在不同的PE树脂中,k2和phi的值没有明显的变化。所有模拟建模结果均与实验流变数据显着一致。这些发现对PE树脂的工业制造具有重要意义。
    The crosslinking behavior of polyethylene (PE) determines its exceptional performance and application. In this study, we investigated the crosslinking behaviors of different PE resins through model simulation and rheological methods. Specifically, the mathematical equation of \"S\" model was established for PE resin. According to this equation, the optimal maximum gel content for high-density polyethylene (HDPE) was found to be around 85%. Moreover, the maximum crosslinking degrees for different PE resins depended largely on their density and molecular weight. The melt viscosities before crosslinking in PE resins were highly influenced by their melt index. The higher melt indexes resulted in the lower storage moduli, improving melt processability during processing. In addition, the crosslinking rates of PE resins were strongly influenced by peroxide concentration, independent of PE resin structures. For high molecular weight and low-density PE resins, they exhibited decreased ti values, increased A0 values, and decreased k6 values. However, there were no noticeable variations in the values of k2 and phi among different PE resins. All simulated modeling outcomes showed remarkable consistency with the experimental rheological data. These findings are of strong significance in the industrial manufacture of PE resin.
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  • 文章类型: Journal Article
    我们研究了在全软骨切除术中PLIF增强交联的临床作用。我们回顾性分析了在2017年1月至2022年3月期间接受单或两段PLIF单侧或双侧全软骨切除术的376例患者。根据是否使用了交联,将患者分为两组。放射学结果测量包括术后12个月计算机断层扫描的融合状态和植入物失败率。患者报告的结果指标包括腰背痛的数字评定量表,Oswestry残疾指数,和简短形式-12物理组件汇总分数,在术前和术后12个月进行评估。手术相关并发症包括手术部位感染,有症状的植入物失败,和硬膜外血肿.在校正混杂因素后,进行倾向评分匹配以比较两组,包括基线和手术程序特征。共有200例纳入倾向得分计算,进行了一对一的匹配,导致56对有和没有交联。融合状态(88.7%vs.85.5%),螺钉松动(14.3%vs.14.3%),网箱沉降(17.9%vs.16.1%),和笼子移位(5.4%与0%)显示有和没有交联的那些之间没有显着差异,分别。两组患者报告的结果或与手术相关的并发症发生率没有显着差异。不建议在PLIF进行全关节切除术期间进行交联增强,因为它不提供任何放射学或临床益处,并且与可避免的费用有关。
    We investigated the clinical role of crosslink augmentation during PLIF with total facetectomy. We retrospectively reviewed 376 patients who underwent one- or two-segment PLIF with unilateral or bilateral total facetectomy between January 2017 and March 2022. The patients were categorized into two groups based on whether a crosslink was instrumented or not. Radiological outcome measurements included fusion status and implant failure rates on 12-month postoperative computed tomography. Patient-reported outcome measures included the Numerical Rating Scale for lower back pain, Oswestry Disability Index, and Short Form-12 Physical Component Summary scores, which were assessed preoperatively and at 12 months postoperatively. Surgery-related complications included surgical site infection, symptomatic implant failure, and epidural hematoma. Propensity score matching was performed to compare both groups after adjusting for confounding factors, including baseline and surgical procedural characteristics. A total of 200 cases were included in the propensity score calculation, and one-to-one matching was performed, resulting in 56 pairs with and without a crosslink. The fusion status (88.7 % vs. 85.5 %), screw loosening (14.3 % vs. 14.3 %), cage subsidence (17.9 % vs. 16.1 %), and cage dislodgement (5.4 % vs. 0 %) showed no significant difference between those with and without a crosslink, respectively. No significant differences were observed in the patient-reported outcomes or surgery-related complication rates between the groups. Crosslink augmentation during PLIF with total facetectomy is not recommended because it does not provide any radiological or clinical benefit and is associated with avoidable expenses.
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  • 文章类型: Journal Article
    肌动球蛋白细胞骨架网络负责各种基本的细胞过程。肌动蛋白网络的组装和维持涉及一系列相关的聚合调节蛋白,分支,交联和收缩驱动的自组织。在这项研究中,我们在体外意外发现肌球蛋白VI和肌球蛋白X,专门用于囊泡运输和丝足病形成的马达蛋白,在不存在其他肌动蛋白相关蛋白的情况下,能够将肌动蛋白交联并自组织成高阶收缩结构。此外,肌球蛋白VI可以单独启动肌动蛋白伸长和分支,并从交联的肌动蛋白聚合物组装分支的力产生网络。肌动蛋白交联蛋白α-肌动蛋白和fascin提供了额外的结构控制。我们的数据确定了网络发展中张力介导的连通性的关键阶段,并为进一步探索肌动球蛋白自组织的非平衡力学提供了模型系统。
    The actomyosin cytoskeletal network is responsible for a variety of fundamental cellular processes. Assembly and maintenance of actin networks involve an array of associated regulatory proteins for polymerization, branching, crosslinking and contractility-driven self-organization. In this study, we make the unexpected discovery in vitro that myosin VI and myosin X, motor proteins specialized in vesicle transport and filopodia formation, are capable of crosslinking and self-organizing actin into higher-order contractile structures in the absence of other actin-associated proteins. Moreover, myosin VI alone can initiate actin elongation and branching, and assemble branched force-generating networks from crosslinked actin polymers. Additional architectural control is provided by the actin crosslinking proteins α-actinin and fascin. Our data identify critical stages of tension-mediated connectivity in network development and provide a model system for further exploration of the nonequilibrium mechanics of actomyosin self-organization.
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  • 文章类型: Journal Article
    肽聚糖是细菌细胞包膜的基本组分,其含有被短肽茎取代的聚糖链。肽茎由D聚合,D-转肽酶,在供体茎4位的氨基酸和受体茎的第三个残基之间形成键(4-3个交联)。一些细菌肽聚糖还含有3-3个交联,这些交联是由另一类称为L,含有YkuD催化结构域的D-转肽酶。在这项工作中,我们研究了不寻常的细菌1-3肽聚糖交联的形成。我们描述了PGFinder软件的一个版本,该软件可以识别1-3个交联,并报告了氧化葡糖杆菌(乙酰杆菌科的模型生物)的高分辨率肽聚糖结构。我们揭示了氧化酵母肽聚糖含有由单个丙氨酸组成的肽茎以及在其C末端具有不寻常氨基酸的几个二肽茎。使用生物信息学方法,我们从转座子文库中鉴定出2个氧化黑曲霉突变体,其中1-3个交联显著减少。通过在异源宿主中的氧化黑曲霉和重组蛋白生产的互补实验,我们识别一个L,D-转肽酶,其结构域与负责这些非规范反应的YkuD结构域远近相关。这项工作重新审视了L,D-转肽酶,一个在细菌肽聚糖重塑中起关键作用的多功能酶家族。
    Peptidoglycan is an essential component of the bacterial cell envelope that contains glycan chains substituted by short peptide stems. Peptide stems are polymerized by D,D-transpeptidases, which make bonds between the amino acid in position four of a donor stem and the third residue of an acceptor stem (4-3 cross-links). Some bacterial peptidoglycans also contain 3-3 cross-links that are formed by another class of enzymes called L,D-transpeptidases which contain a YkuD catalytic domain. In this work, we investigate the formation of unusual bacterial 1-3 peptidoglycan cross-links. We describe a version of the PGFinder software that can identify 1-3 cross-links and report the high-resolution peptidoglycan structure of Gluconobacter oxydans (a model organism within the Acetobacteraceae family). We reveal that G. oxydans peptidoglycan contains peptide stems made of a single alanine as well as several dipeptide stems with unusual amino acids at their C-terminus. Using a bioinformatics approach, we identified a G. oxydans mutant from a transposon library with a drastic reduction in 1-3 cross-links. Through complementation experiments in G. oxydans and recombinant protein production in a heterologous host, we identify an L,D-transpeptidase enzyme with a domain distantly related to the YkuD domain responsible for these non-canonical reactions. This work revisits the enzymatic capabilities of L,D-transpeptidases, a versatile family of enzymes that play a key role in bacterial peptidoglycan remodelling.
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  • 文章类型: Journal Article
    已知离子的迁移与各种有害现象有关,包括电流密度-电压滞后,相偏析,等。,这极大地限制了钙钛矿太阳能电池的稳定性和性能,阻碍他们向商业应用的进展。为了应对这些挑战,我们建议加入可聚合的有机小分子单体,N-氨基甲酰基-2-丙-2-基戊-4-烯酰胺(丙烯酸),通过热交联形成交联聚合物(P-Apronal)。Apronal中的羰基和氨基与浅层缺陷有效地相互作用,如不配位的Pb2+和碘空位,导致形成具有增强的结晶度和降低的晶格应变的高质量薄膜。此外,P-Apronal的引入改善了能级对准,并促进电荷载流子的提取和传输,导致25.09%的冠军效率。重要的是,P-Apronal能有效抑制离子的迁移,提高器件的长期稳定性。本策略提出了在钙钛矿太阳能电池中获得长期稳定性和增强效率的途径。
    The migration of ions is known to be associated with various detrimental phenomena, including current density-voltage hysteresis, phase segregation, etc., which significantly limit the stability and performance of perovskite solar cells, impeding their progress toward commercial applications. To address these challenges, we propose incorporating a polymerizable organic small molecule monomer, N-carbamoyl-2-propan-2-ylpent-4-enamide (Apronal), into the perovskite film to form a crosslinked polymer (P-Apronal) through thermal crosslinking. The carbonyl and amino groups in Apronal effectively interact with shallow defects, such as uncoordinated Pb2+ and iodide vacancies, leading to the formation of high-quality films with enhanced crystallinity and reduced lattice strain. Furthermore, the introduction of P-Apronal improves energy level alignment, and facilitates charge carrier extraction and transport, resulting in a champion efficiency of 25.09 %. Importantly, P-Apronal can effectively suppress the migration of I- ions and improve the long-term stability of the devices. The present strategy sets forth a path to attain long-term stability and enhanced efficiency in perovskite solar cells.
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  • 文章类型: Journal Article
    交联在胶原基组织中起重要作用,因为它影响机械行为和组织代谢。衰老和糖尿病影响交联的类型和密度,有效改变组织性质。然而,大多数研究集中在大压力下的这些影响,而不是日常活动。我们关注整合素结合位点的变形机制和结构变化,蛋白聚糖,和胶原酶在胶原纤维中使用完全原子模型。我们证明了高连接酶交联(我们的“HC”模型,代表正常组织)和晚期糖基化终产物(我们的“葡萄糖”模型,糖尿病的增加)导致日常活动下的均匀变形,但是低连接酶交联(我们的“LC”模型,代表老化的组织)不。特别是,HC模型显示更多的滑动,这可以解释健康组织吸收更多应变能的能力。相比之下,AGEs诱导结合位点附近结构的不稳定性,这将影响胶原蛋白分子的组织代谢。我们的结果为胶原蛋白的分子机制提供了重要的见解,并为交联在日常活动中的组织中的作用提供了可能的解释。
    Crosslinking plays an important role in collagen-based tissues since it affects mechanical behavior and tissue metabolism. Aging and diabetes affect the type and density of crosslinking, effectively altering tissue properties. However, most studies focus on these effects under large stress rather than daily activities. We focus on the deformation mechanisms and structural change at the binding sites for integrins, proteoglycans, and collagenase in collagen fibrils using a fully atomistic model. We show that high-connectivity enzymatic crosslinking (our \"HC\" model, representing normal tissues) and advanced-glycation end-products (our \"Glucosepane\" model, which increase in diabetes) result in uniform deformation under daily activity, but low-connectivity enzymatic crosslinking (our \"LC\" model, representing aging tissues) does not. In particular, the HC model displays more sliding, which may explain the ability of healthy tissues to absorb more strain energy. In contrast, AGEs induce instability in the structures near the binding sites, which would affect the tissue metabolism of the collagen molecule. Our results provide important insights into the molecular mechanisms of collagen and a possible explanation for the role of crosslinking in tissues undergoing daily activity.
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