glass transition

玻璃化转变
  • 文章类型: Journal Article
    传统的固体口服剂型开发通常不会受到依赖无定形药物作为药物产品中的直接成分的挑战。因为这可能会导致工艺设计和放大带来的产品开发障碍,物理质量属性的控制,药品的加工性能和稳定性。这里,我们介绍化学,无定形药物成功商业化背后的制造和控制发展历程,Elagolix钠,一流的,口服活性促性腺激素释放激素拮抗剂。通过分子动力学(MD)在分子和分子间水平上评估了缺乏结晶状态的原因,揭示了由于分子内氢键普遍存在而导致的成核障碍,API分子之间的排斥相互作用和强溶剂化效应。为API制造工艺的设计提供基础依据,我们通过MD对溶剂诱导的塑化行为进行了实验和计算建模,以了解分子迁移率。此外,我们应用材料科学四面体概念将API孔隙率与药物产品片剂可压缩性联系起来。最后,我们设计了API隔离流程,将计算流体动力学模型纳入撞击射流混合器的设计中,用于滤饼洗涤中的沉淀和溶剂依赖性玻璃化转变关系,排放和干燥过程,为了实现多孔材料的一致制造,非烧结无定形API粉末,适用于强大的药物产品制造。
    Conventional solid oral dosage form development is not typically challenged by reliance on an amorphous drug substance as a direct ingredient in the drug product, as this may result in product development hurdles arising from process design and scale-up, control of physical quality attributes, drug product processability and stability. Here, we present the Chemistry, Manufacturing and Controls development journey behind the successful commercialization of an amorphous drug substance, Elagolix Sodium, a first-in-class, orally active gonadotropin-releasing hormone antagonist. The reason behind the lack of crystalline state was assessed via Molecular Dynamics (MD) at the molecular and inter-molecular level, revealing barriers for nucleation due to prevalence of intra-molecular hydrogen bond, repulsive interactions between API molecules and strong solvation effects. To provide a foundational basis for the design of the API manufacturing process, we modeled the solvent-induced plasticization behavior experimentally and computationally via MD for insights into molecular mobility. In addition, we applied material science tetrahedron concepts to link API porosity to drug product tablet compressibility. Finally, we designed the API isolation process, incorporating computational fluid dynamics modeling in the design of an impinging jet mixer for precipitation and solvent-dependent glass transition relationships in the cake wash, blow-down and drying process, to enable the consistent manufacture of a porous, non-sintered amorphous API powder that is suitable for robust drug product manufacturing.
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  • 文章类型: Journal Article
    纤维素,自然界中丰富的生物聚合物,作为植物细胞壁的结构成分,具有天然的半结晶结构,其中无定形结晶域的排列控制着其关键特性,例如机械和物理化学特性。材料在不同情况下的性能由分子迁移率决定,这影响了诸如机械性能之类的属性,化学反应性,和吸水。然而,通过实验研究富纤维素材料的结构和动态性能是很困难的。玻璃化转变尤其如此,影响其质量和性能。该实验挑战显著地由整个文献中的数据的相当大的可变性证明。这项研究的目的是提供一个全面的多尺度的动态探索在富含纤维素的材料,强调有关纤维素玻璃化转变和分子弛豫的文献数据,并提供对表征其物理状态的方法的见解,并强调水-纤维素相互作用对这些系统中分子迁移率的影响。使用多种方法获得的有希望的结果显示出结合方法的重要性,以实现对纤维素材料中复杂的热转变的更准确和详细的理解。特别是在考虑水对其热动力学和性能的影响时。
    Cellulose, an abundant biopolymer in nature as a structural component of plant cell walls, has a native semi-crystalline structure in which the arrangement of amorphous-crystalline domains governs its key properties such as mechanical and physico-chemical properties. The performance of the material in different situations is shaped by molecular mobility, which affects attributes such as mechanical properties, chemical reactivity, and water absorption. Nevertheless, it is difficult to investigate experimentally the structural and dynamic properties of cellulose-rich materials. This is especially the case for the glass transition, which impacts its quality and properties. This experimental challenge is notably evidenced by the considerable variability in data across the literature. The purpose of this study is to offer a comprehensive multi-scale exploration of dynamics within cellulose-rich materials, emphasizing literature data on cellulose glass transition and molecular relaxations, and providing insights into methods for characterizing their physical state and underscoring the impact of water-cellulose interactions on molecular mobility in these systems. The promising results obtained using multiple approaches bring out the importance of combining methods to achieve a more accurate and detailed understanding of the complex thermal transition in cellulose materials, particularly when considering the influence of water on their thermal dynamics and properties.
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  • 文章类型: Journal Article
    玻璃混合金属卤化物由于其高结构可调性和低熔点,近年来已成为有前途的材料,提供独特的优点,克服了晶体和多晶对应物以及其他常规非晶半导体的局限性。这篇综述文章全面探讨了其结构特征,电子性质,和混合金属卤化物的化学配位,强调它们在从结晶相到非晶相的玻璃化转变中的作用。我们研究了非晶相内促进光传输的内在无序,并通过优化玻璃混合金属卤化物的电荷传输来讨论器件体系结构和界面工程的最新进展,以实现高质量的应用。具有充分的理论认识和合理的结构设计,在显示器中的潜在应用,信息存储,X射线成像,和感应被突出显示,强调玻璃态混合金属卤化物在材料科学和信息科学领域的变革性影响。
    Glassy hybrid metal halides have emerged as promising materials in recent years due to their high structural adjustability and low melting points, offering unique merits that overcome the limitations of their crystalline and polycrystalline counterparts as well as other conventional amorphous semiconductors. This review article comprehensively explores the structural characteristics, electronic properties, and chemical coordination of hybrid metal halides, emphasizing their role in the glass transition from the crystalline phase to the amorphous phase. We examine the intrinsic disorder within the amorphous phase that facilitates light transmission and discuss recent advances in device architecture and interface engineering by optimizing the charge transport of glassy hybrid metal halides for high-quality applications. With full theoretical understanding and rational structural design, potential applications in displays, information storage, X-ray imaging, and sensing are highlighted, underscoring the transformative impact of glassy hybrid metal halides in the fields of materials science and information science.
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  • 文章类型: Journal Article
    古代DNA的分析通常涉及对存活的短寡核苷酸进行测序,并与相关的基因组装配进行比对,现代物种这里,我们报告说,在52,000年前死亡的雌性羊毛猛犸象的皮肤保留了其古老的基因组结构。我们使用PaleoHi-C绘制染色质接触图并组装其基因组,产生28个染色体长度的支架。染色体区域,隔室,循环,巴尔的尸体,和不活跃的X染色体(Xi)超域持续存在。猛犸象皮肤中活跃和不活跃的基因组区室比其他大象组织更像亚洲象皮肤。我们的分析揭示了新的生物学。区室化的差异揭示了猛犸象与猛犸象的转录可能发生改变的基因。大象。MammothXi有一个传统的建筑,而不是像人类和老鼠那样的两股。我们假设,这只猛犸象死后不久,样品在西伯利亚寒冷中自发冻干,导致玻璃化转变,在纳米尺度上保存了古代染色体的亚化石。
    Analyses of ancient DNA typically involve sequencing the surviving short oligonucleotides and aligning to genome assemblies from related, modern species. Here, we report that skin from a female woolly mammoth (†Mammuthus primigenius) that died 52,000 years ago retained its ancient genome architecture. We use PaleoHi-C to map chromatin contacts and assemble its genome, yielding 28 chromosome-length scaffolds. Chromosome territories, compartments, loops, Barr bodies, and inactive X chromosome (Xi) superdomains persist. The active and inactive genome compartments in mammoth skin more closely resemble Asian elephant skin than other elephant tissues. Our analyses uncover new biology. Differences in compartmentalization reveal genes whose transcription was potentially altered in mammoths vs. elephants. Mammoth Xi has a tetradic architecture, not bipartite like human and mouse. We hypothesize that, shortly after this mammoth\'s death, the sample spontaneously freeze-dried in the Siberian cold, leading to a glass transition that preserved subfossils of ancient chromosomes at nanometer scale.
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  • 文章类型: Journal Article
    密集包装,能动细菌可以采取传统上没有的集体状态,被动材料。这些国家在许多方面仍然神秘,和它们的物理特性可以帮助我们理解自然细菌菌落和生物膜以及一般材料。这里,我们克服了与产生均匀生长相关的挑战,大,通过基于膜的微流体装置进行准二维细菌组装,并报道了大肠杆菌二维悬浮液中玻璃态的出现。随着细胞生长的增加,数量密度增加,活动细菌种群过渡到玻璃态,细胞被塞满而无法移动。这分两步进行,第一种仅抑制定向模式,第二种完全玻璃化运动。通过对细菌个体运动的统计分析和调查来表征每个阶段,我们不仅发现玻璃的特征,如快速减速,动态异质性,和笼子效应,还有一些与热玻璃不同的特性。这些独特的特性包括具有集体运动的对齐细胞的微域的自发形成,动态磁化率中异常信号的出现,以及热系统通常禁止密度依赖的动态减速。我们的结果有望捕捉到这种活性棒玻璃的一般特征,这可能是致密细菌聚集体的物理机制。
    Densely packed, motile bacteria can adopt collective states not seen in conventional, passive materials. These states remain in many ways mysterious, and their physical characterization can aid our understanding of natural bacterial colonies and biofilms as well as materials in general. Here, we overcome challenges associated with generating uniformly growing, large, quasi-two-dimensional bacterial assemblies by a membrane-based microfluidic device and report the emergence of glassy states in two-dimensional suspension of Escherichia coli. As the number density increases by cell growth, populations of motile bacteria transition to a glassy state, where cells are packed and unable to move. This takes place in two steps, the first one suppressing only the orientational modes and the second one vitrifying the motion completely. Characterizing each phase through statistical analyses and investigations of individual motion of bacteria, we find not only characteristic features of glass such as rapid slowdown, dynamic heterogeneity, and cage effects, but also a few properties distinguished from those of thermal glass. These distinctive properties include the spontaneous formation of micro-domains of aligned cells with collective motion, the appearance of an unusual signal in the dynamic susceptibility, and the dynamic slowdown with a density dependence generally forbidden for thermal systems. Our results are expected to capture general characteristics of such active rod glass, which may serve as a physical mechanism underlying dense bacterial aggregates.
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  • 文章类型: Journal Article
    保存从传统奶酪制作过程中获得的微生物生态系统对于保护微生物奶酪群落的生物多样性至关重要,从而确保保持传统奶酪的高风味品质。很少有人提出用于长期储存微生物聚生体的方案。这项工作旨在开发保存方法,以稳定涂抹成熟奶酪中的整个微生物群落,而无需繁殖或分离。一个简化的微生物群落,能够再现奶酪成熟的代谢模式,在三个独立的奶酪生产中使用。在成熟步骤之前和之后采集奶酪样品,与麦芽糊精或盐溶液混合,并经受不同的稳定条件,包括冷冻和冷冻干燥,然后储存1个月。使用菌落形成单位测定法定量微生物存活。使用差示扫描量热法将样品内发生的物理事件与微生物储存稳定性相关联。在-80°C下冷冻导致最低的可培养性损失(<0.8对数单位),然后在-20°C下冷冻并冷冻干燥。成熟细菌似乎是群落中最敏感的微生物。此外,使用最稳定的群落成功的奶酪生产表明,可以保存和重新使用整个感兴趣的微生物群落。
    Preserving microbial ecosystems obtained from traditional cheese-making processes is crucial to safeguarding the biodiversity of microbial cheese communities and thus ensuring that the high flavor quality of traditional cheeses is maintained. Few protocols have been proposed for the long-term storage of microbial consortia. This work aimed to develop preservation methods to stabilize the entire microbial community in smear-ripened cheese without multiplication or isolation. A simplified microbial community, capable of reproducing the metabolic pattern of cheese maturation, was used in three independent cheese productions. Cheese samples were taken before and after the ripening step, mixed with maltodextrin or saline solution, and subjected to different stabilization conditions including freezing and freeze-drying, followed by 1 month of storage. Microbial survival was quantified using the colony-forming unit assay. Differential scanning calorimetry was used to relate the physical events occurring within the samples to the microbial storage stability. Freezing at -80 °C resulted in the lowest loss of culturability (<0.8 log unit), followed by freezing at -20 °C and freeze-drying. The ripening bacteria appeared as the most sensitive microorganisms within the community. Moreover, a successful cheese production using the best-stabilized community showed the possibility of preserving and re-using an entire microbial community of interest.
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  • 文章类型: Journal Article
    这项研究调查了马铃薯和啤酒花花粉的热特性,用于冷冻保存和随后的杂交育种。使用差示扫描量热计(DSC)测量选定花粉样品中的相变和冷冻水含量。不像啤酒花花粉,马铃薯花粉在热特性和水分含量方面表现出很高的变异性。通过DSC在马铃薯中区分了三种特定类型的花粉样品,这些花粉样品基于其热特性和水含量:(1)玻璃状,含水量低于每克干物质0.21克水;(2)“瞬态”,含水量在每克干物质0.27至0.34克水之间;(3)“冷冻”,水含量高于每克干物质0.34克水。只有含水量低的“玻璃状”花粉样品显示出适合在马铃薯和啤酒花中冷冻保存的长期储存特性。花粉的冷冻保存并没有显着降低其活力,冷冻保存的花粉已成功用于生产马铃薯和啤酒花杂种。结果表明,冷冻保存是在育种过程中对这些作物花粉进行保存和利用的可行技术。
    This study investigated the thermal properties of potato and hop pollen for cryopreservation and subsequent cross-breeding. Phase transitions and frozen water content in selected pollen samples were measured using a differential scanning calorimeter (DSC). Unlike hop pollen, potato pollen showed high variability in thermal properties and water content. Three specific types of pollen samples based on their thermal characteristics and water content were distinguished by DSC in potato: (1) \'glassy\', with a water content lower than 0.21 g water per g dry matter; (2) \'transient\', with a water content between 0.27 and 0.34 g of water per g of dry matter; (3) \'frozen\', with a water content higher than 0.34 g of water per g of dry matter. Only the \'glassy\' pollen samples with a low water content showed suitable properties for its long-term storage using cryopreservation in potato and hops. Cryopreservation of pollen did not significantly reduce its viability, and cryopreserved pollen was successfully used to produce both potato and hop hybrids. The results indicate that cryopreservation is a feasible technique for the preservation and utilization of pollen of these crops in the breeding process.
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  • 文章类型: Journal Article
    这项工作的目的是研究整个油炸过程中的小麦面筋蛋白网络结构,并评估其对油炸诱导的微观和宏观结构发育的贡献。面筋聚合,面筋-水相互作用,对于不同水合水平(40-60%水分含量)的面筋-水模型系统,评估了分子迁移率与油炸时间(0-180s)的关系。结果表明,深层油炸(5s)后,面筋蛋白的可提取性大大降低,这主要是由于二硫化物共价交联导致的面筋蛋白聚合。更强的麦醇溶蛋白和谷蛋白蛋白-蛋白相互作用归因于共价键的形成和与蛋白质链相互作用的水的蒸发。长时间的油炸(>60s)导致蛋白质可提取性逐渐降低,主要是由于麦醇溶蛋白可提取性的损失,通过巯基-二硫化物交换反应与麦醇溶蛋白与谷蛋白共聚合有关。面筋聚合物的迁移率在油炸过程中显著降低(基于代表面筋非交换质子的质子部分的较低T2弛豫时间),面筋蛋白逐渐从橡胶态转变为玻璃态(基于所述质子的面积增加)。油炸过程中的样品体积与谷蛋白非交换质子的蛋白质可提取性降低(r=-0.792,p<0.001)和T2弛豫时间密切相关(r=-0.866,p<0.001),因此证明油炸导致的谷蛋白结构扩展程度取决于蛋白质的聚合及其分子迁移率的降低。
    The aim of this work was to investigate wheat gluten protein network structure throughout the deep-frying process and evaluate its contribution to frying-induced micro- and macrostructure development. Gluten polymerization, gluten-water interactions, and molecular mobility were assessed as a function of the deep-frying time (0 - 180 s) for gluten-water model systems of differing hydration levels (40 - 60 % moisture content). Results showed that gluten protein extractability decreased considerably upon deep frying (5 s) mainly due to glutenin polymerization by disulfide covalent cross-linking. Stronger gliadin and glutenin protein-protein interactions were attributed to the formation of covalent linkages and evaporation of water interacting with protein chains. Longer deep-frying (> 60 s) resulted in progressively lower protein extractabilities, mainly due to the loss in gliadin protein extractability, which was associated with gliadin co-polymerization with glutenin by thiol-disulfide exchange reactions. The mobility of gluten polymers was substantially reduced during deep-frying (based on the lower T2 relaxation time of the proton fraction representing the non-exchanging protons of gluten) and gluten proteins gradually transitioned from the rubbery to the glassy state (based on the increased area of said protons). The sample volume during deep-frying was strongly correlated to the reduced protein extractability (r = -0.792, p < 0.001) and T2 relaxation time of non-exchanging protons of gluten proteins (r = -0.866, p < 0.001) thus demonstrating that the extent of gluten structural expansion as a result of deep-frying is dictated both by the polymerization of proteins and the reduction in their molecular mobility.
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  • 文章类型: Journal Article
    我们报道了在形成含有长春西汀和苹果酸的新多组分结晶固体时,对映选择性的一个有趣例子。几个实验数据集证实,多组分体系在固态和溶液中都表现出明显的对映特异性结晶行为:只有由长春西汀和L-苹果酸组成的体系才能产生由新晶形组成的自由流动固体,而使用D-苹果酸的实验产生了无定形且经常潮解的材料。新的长春西汀-L-苹果酸系统在P21的单斜空间群中以1:1M的比例结晶,其中两个分子通过不对称单元中的分子间氢键连接。长春西汀-DL-苹果酸体系是部分结晶的(也有痕量的未反应的长春西汀),其衍射峰对应于长春西汀-L-苹果酸的衍射峰。固态NMR实验表明,在所有三个系统中都有很强的离子相互作用。然而,长春西汀-L-苹果酸体系是纯的结晶相,在另外两个系统中,总是检测到存在未反应的长春西汀。这导致长春西汀-L-苹果酸纯结晶盐的溶出曲线显著恶化,其溶解动力学表现优越。
    We report an intriguing example of enantioselectivity in the formation of new multicomponent crystalline solid containing vinpocetine and malic acid. Several experimental data sets confirmed that the multicomponent system presents a clear enantiospecific crystallisation behaviour both in the solid-state and in solution: only the system consisting of vinpocetine and L-malic acid produces a free-flowing solid consisting of a new crystalline form, while the experiments with D-malic acid produced an amorphous and often deliquescent material. The new vinpocetine-L-malic system crystallizes in the monoclinic space group of P21 and in a 1:1 molar ratio, where the two molecules are linked through intermolecular hydrogen bonds in the asymmetric unit. The vinpocetine-DL-malic system was partially crystalline (with also traces of unreacted vinpocetine) with diffraction peaks corresponding to those of vinpocetine-L-malic acid. Solid-state NMR experiments revealed strong ionic interactions in all the three systems. However, while vinpocetine-L-malic acid system was a pure and crystalline phase, the other two systems persistently showed the presence of unreacted vinpocetine. This resulted in a significant worsening of the dissolution profile with respect to the pure vinpocetine-L-malic crystalline salt, whose dissolution kinetics appeared superior.
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  • 文章类型: Journal Article
    水溶性碳水化合物通常以无定形状态存在于食品中,并在玻璃化转变温度(Tg)下经历玻璃化-橡胶转变(玻璃化转变)。临界水含量(Wc)和临界水活度(awc)是在298K(典型环境温度)下发生玻璃化转变的水含量和水活度(aw),分别。对于无定形水溶性碳水化合物,Wc可以使用先前报道的方程式从无水固体(Tgs)的Tg预测。然而,仍然缺乏预测awc的方法。本研究旨在建立基于Tgs的无定形水溶性碳水化合物的awc预测方法。首先,研究了四种氢化淀粉水解产物的吸水率等温线,并使用古根海姆-安德森-德布尔(GAB)模型对结果进行分析。第二,Tgs对GAB参数的影响(C,K,和Wm)使用以前文献中报道的Tgs值进行评估。C和Wm呈对数减少和增加,分别,随着1/Tgs的增加。K固定为1(常数),因为它几乎没有变化。这些结果使得能够从Tgs预测GAB参数。然后,GAB模型可以从Wc预测awc,这是使用先前建立的方程式确定的。预测的awc值与实验确定的awc非常吻合。此外,我们证明了这种awc预测方法也适用于无定形水溶性电解质和部分水不溶性碳水化合物。因此,该方法可用于无定形水溶性碳水化合物和碳水化合物食品的质量控制。
    Water-soluble carbohydrates commonly exist in an amorphous state in foods and undergo glass-rubber transition (glass transition) at the glass transition temperature (Tg). The critical water content (Wc) and critical water activity (awc) are the water content and water activity (aw) at which the glass transition occurs at 298 K (typical ambient temperature), respectively. For amorphous water-soluble carbohydrates, Wc can be predicted from the Tg of anhydrous solid (Tgs) using previously reported equations. However, an approach for predicting awc is still lacking. This study aimed to establish an awc-predictive approach for amorphous water-soluble carbohydrates based on Tgs. First, the water sorption isotherms of four hydrogenated starch hydrolysates were investigated, and the results were analyzed using the Guggenheim-Anderson-de Boer (GAB) model. Second, the effect of Tgs on the GAB parameters (C, K, and Wm) was evaluated using the Tgs values reported in previous literatures. C and Wm decreased and increased logarithmically, respectively, with increasing 1/Tgs. K was fixed to 1 (constant), as it showed little variation. These results enabled the prediction of the GAB parameters from Tgs. The GAB model could then predict awc from Wc, which was determined using the previously established equations. The predicted awc values were in good agreement with the experimentally determined awc. Additionally, we demonstrated that this awc-prediction approach is also applicable to amorphous water-soluble electrolytes and partially water-insoluble carbohydrates. Thus, this approach can be used for the quality control of amorphous water-soluble carbohydrates and carbohydrate-based foods.
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