Heat resistance

耐热性
  • 文章类型: Journal Article
    设计具有优异综合性能的耐热热固性塑料一直是一个长期的挑战。各种高性能热固性塑料的共固化是一种有效的策略,然而,传统的试错实验发现新材料的研究周期长。在这里,提出了一种两步机器学习(ML)辅助方法来设计由聚酰亚胺(PI)和含硅芳基乙炔(PSA)组成的耐热共固化树脂,也就是说,聚(硅-炔酰亚胺)(PSI)。首先,建立了两种ML预测模型来评估PI的加工性能及其与PSA的相容性。然后,开发了另外两个ML模型来预测共固化PSI树脂的热分解温度和弯曲强度。PSI树脂的最佳分子结构和组成是高通量筛选的。筛选的PSI树脂经过实验验证,具有增强的耐热性,韧性,和可加工性。在这项工作中建立的研究框架可以推广到其他先进的多组分聚合物材料的合理设计。
    Designing heat-resistant thermosets with excellent comprehensive performance has been a long-standing challenge. Co-curing of various high-performance thermosets is an effective strategy, however, the traditional trial-and-error experiments have long research cycles for discovering new materials. Herein, a two-step machine learning (ML) assisted approach is proposed to design heat-resistant co-cured resins composed of polyimide (PI) and silicon-containing arylacetylene (PSA), that is, poly(silicon-alkyne imide) (PSI). First, two ML prediction models are established to evaluate the processability of PIs and their compatibility with PSA. Then, another two ML models are developed to predict the thermal decomposition temperature and flexural strength of the co-cured PSI resins. The optimal molecular structures and compositions of PSI resins are high-throughput screened. The screened PSI resins are experimentally verified to exhibit enhanced heat resistance, toughness, and processability. The research framework established in this work can be generalized to the rational design of other advanced multi-component polymeric materials.
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  • 文章类型: Journal Article
    兼具高韧性和耐热性的聚合物纤维很难实现,which,然而,在航空航天和军事等苛刻的应用中拥有巨大的希望。由于具有刚性分子结构的传统耐热材料通常缺乏能量耗散机制,因此存在这种禁止性设计任务。芳纶纳米纤维作为高性能的纳米级建筑单元,由于其耐人寻味的机械和热性能而受到了极大的关注,但是它们独特的结构特征尚未被完全捕获。我们表明芳纶纳米纤维在去除水的过程中会形成纳米级的卷曲,主要存在于褶板的缺陷平面上,可以发生折叠的地方。这种结构松弛的精确控制可以通过在水凝胶纤维上施加轴向载荷来实现。这允许出现具有不同卷曲角度的芳族聚酰胺纤维。这些卷曲纤维具有高韧性和耐热性,由于具有刚性分子结构的聚(对苯二甲酰对苯二胺)的纳米级卷曲的可延伸性质,有希望作为稳定的可拉伸电子设备的模板。抗拉强度/模量(392-944MPa/11-29GPa),拉伸性(25-163%),和韧性(154-445MJ/cm3)根据卷曲程度来实现。有趣的是,在低于松弛温度(259°C)煅烧50小时后,可以保持约430MJ/m3的韧性。即使在300°C煅烧10小时后,保持310MJ/m3的韧性,优于现有的聚合物材料。我们基于含水芳族聚酰胺纳米纤维的多尺度设计策略为解决实现相互矛盾的特性组合的挑战提供了有效的途径。
    Polymer fibers that combine high toughness and heat resistance are hard to achieve, which, however, hold tremendous promise in demanding applications such as aerospace and military. This prohibitive design task exists due to the opposing property dependencies on chain dynamics because traditional heat-resistant materials with rigid molecular structures typically lack the mechanism of energy dissipation. Aramid nanofibers have received great attention as high-performance nanoscale building units due to their intriguing mechanical and thermal properties, but their distinct structural features are yet to be fully captured. We show that aramid nanofibers form nanoscale crimps during the removal of water, which primarily resides at the defect planes of pleated sheets, where the folding can occur. The precise control of such a structural relaxation can be realized by exerting axial loadings on hydrogel fibers, which allows the emergence of aramid fibers with varying angles of crimps. These crimped fibers integrate high toughness with heat resistance, thanks to the extensible nature of nanoscale crimps with rigid molecular structures of poly(p-phenylene terephthalamide), promising as a template for stable stretchable electronics. The tensile strength/modulus (392-944 MPa/11-29 GPa), stretchability (25-163%), and toughness (154-445 MJ/cm3) are achieved according to the degree of crimping. Intriguingly, a toughness of around 430 MJ/m3 can be maintained after calcination below the relaxation temperature (259 °C) for 50 h. Even after calcination at 300 °C for 10 h, a toughness of 310 MJ/m3 is kept, outperforming existing polymer materials. Our multiscale design strategy based on water-bearing aramid nanofibers provides a potent pathway for tackling the challenge for achieving conflicting property combinations.
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  • 文章类型: Journal Article
    衰老和年龄相关疾病与氧化应激和炎症错综复杂。非甾体抗炎药(NSAIDs)已显示出在减轻与年龄有关的疾病和延长各种模式生物寿命方面的希望。然而,NSAIDs在老年个体中的疗效可能受到药物代谢和耐受性的年龄相关变化的影响。这可能导致年龄依赖性毒性。本研究旨在评估与常用NSAIDs(阿司匹林,布洛芬,对乙酰氨基酚,和吲哚美辛)的寿命,healthspan,和氧化应激水平在年轻和老年秀丽隐杆线虫。结果表明,阿司匹林和布洛芬能够通过抑制ROS的产生和增强抗氧化SOD基因的表达来延长幼龄蠕虫的寿命。相比之下,对乙酰氨基酚和吲哚美辛加速了老蠕虫的衰老过程,通过pmk-1/skn-1途径导致氧化应激损伤并降低对热应力的抵抗力。值得注意的是,当pmk-1(km25)菌株中pmk-1被敲除时,对乙酰氨基酚和吲哚美辛的有害作用得以减轻。这些结果强调了由于老年人对毒性的敏感性增加,对乙酰氨基酚和吲哚美辛可能缺乏益处。进一步的研究对于阐明驱动这些年龄依赖性反应的潜在机制以及评估与老年人群使用NSAID相关的潜在风险至关重要。
    Aging and age-related diseases are intricately associated with oxidative stress and inflammation. Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown their promise in mitigating age-related conditions and potentially extending lifespan in various model organisms. However, the efficacy of NSAIDs in older individuals may be influenced by age-related changes in drug metabolism and tolerance, which could result in age-dependent toxicities. This study aimed to evaluate the potential risks of toxicities associated with commonly used NSAIDs (aspirin, ibuprofen, acetaminophen, and indomethacin) on lifespan, healthspan, and oxidative stress levels in both young and old Caenorhabditis elegans. The results revealed that aspirin and ibuprofen were able to extend lifespan in both young and old worms by suppressing ROS generation and enhancing the expression of antioxidant SOD genes. In contrast, acetaminophen and indomeacin accelerated aging process in old worms, leading to oxidative stress damage and reduced resistance to heat stress through the pmk-1/skn-1 pathway. Notably, the harmful effects of acetaminophen and indomeacin were mitigated when pmk-1 was knocked out in the pmk-1(km25) strain. These results underscore the potential lack of benefit from acetaminophen and indomeacin in elderly individuals due to their increased susceptibility to toxicity. Further research is essential to elucidate the underlying mechanisms driving these age-dependent responses and to evaluate the potential risks associated with NSAID use in the elderly population.
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  • 文章类型: Journal Article
    近年来,交联技术已被发现并广泛应用于食品中,纺织品,Pharmaceutical,生物工程等领域。交联是两个或两个以上分子相互键合形成稳定的三维网络结构以提高强度的反应,物质的耐热性和其他性质。研究人员发现,交联技术对提高胶体传递系统的热稳定性有显著作用。在本文中,综述了可用于提高胶体递送系统热稳定性的交联技术,包括酶-,离子-,chemical-,和组合交联。最初,综述了这些交联技术的基本机理。然后,讨论了交联对胶体给药系统热稳定性的影响。最后,交联递送系统在改善益生菌热稳定性中的应用,多酚,颜料,介绍了食品和食品包装材料中的营养成分。蛋白质和多糖形成热稳定的胶体递送系统的能力可以通过交联来提高。然而,需要更多的研究来确定不同交联对更广泛的不同递送系统的热稳定性的影响,以及确保其安全性和有效性。
    In recent years, crosslinking technology has been found and widely used in food, textile, pharmaceutical, bioengineering and other fields. Crosslinking is a reaction in which two or more molecules bond to each other to form a stable three-dimensional network structure to improve the strength, heat resistance and other properties of substances. The researchers found that the cross-linking technology has a significant effect on improving the thermal stability of the colloidal delivery system. In this paper, crosslinking techniques that can be used to improve the thermal stability of colloidal delivery systems are reviewed, including enzyme-, ion-, chemical-, and combined cross-linking. Initially, the underlying mechanisms of these crosslinking technologies is reviewed. Then, the impacts of crosslinking on the heat-stability of colloidal delivery systems are discussed. Finally, the application of crosslinked delivery systems in improving the thermal stability of probiotics, polyphenols, pigments, and nutrients in foods and food packaging materials is introduced. The ability of proteins and polysaccharides to form heat-stable colloidal delivery systems can be improved by crosslinking. Nevertheless, more research is required to establish the impact of different crosslinking on the thermal stability of a broader range of different delivery systems, as well as to ensure their safety and efficacy.
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  • 文章类型: Journal Article
    海洋热浪(MHW)对潮间带双壳类动物及其维持的生态系统产生重大影响,造成生物原始栖息地的破坏。Saccostreamordax主要居住在赤道周围的潮间带,表现出对高温的潜在耐受性,可能是适合栖息地恢复的物种。然而,关于S.mordax对高温的耐受机制的理解尚不清楚。还不清楚S.mordax可以容忍强度和频率不断增加的重复热浪的程度。这里,我们模拟了MHW的两种情况的影响,并测量了S.mordax的生理生化反应和基因表达谱。预测的响应在热浪中变化很大,并且没有热浪对S.mordax的生存产生重大影响。具体来说,在反复的热浪中,牡蛎的标准代谢率和酶活性没有统计学上的显着变化。暴露于高强度热浪的S.mordax可提高其标准代谢率,以促进基本的生理维持,并增加SOD的活性和HSP70/90的表达。这些策略大概是以牺牲与免疫和生长有关的功能为代价的,最好的例子是酶活性的显著降低(NaK,CaMg,T-ATP,和AKP)和基因的表达水平(Rab,eEF-2,HMGR,Rac1,SGK,Rab8等).S.mordax的性能状态倾向于通过在重新暴露于热浪时在生物组织的各个层面上实施一套能耗较低的补偿机制来改善。S.mordax显示的适应能力表明,它们可以在热带海洋牡蛎礁的恢复中发挥关键作用。
    Marine heatwaves (MHWs) have a significant impact on intertidal bivalves and the ecosystems they sustain, causing the destruction of organisms\' original habitats. Saccostrea mordax mainly inhabits the intertidal zone around the equator, exhibiting potential tolerance to high temperatures and maybe a species suitable for habitat restoration. However, an understanding about the tolerance mechanism of S. mordax to high temperatures is unclear. It is also unknown the extent to which S. mordax can tolerate repeated heatwaves of increasing intensity and frequency. Here, we simulated the effects of two scenarios of MHWs and measured the physiological and biochemical responses and gene expression spectrum of S. mordax. The predicted responses varied greatly across heatwaves, and no heatwave had a significant impact on the survival of S. mordax. Specifically, there were no statistically significant changes apparent in the standard metabolic rate and the activities of enzymes of the oyster during repeated heatwaves. S. mordax exposed to high-intensity heatwaves enhanced their standard metabolic rate to fuel essential physiological maintenance and increasing activity of SOD and expression of HSP70/90. These strategies are presumably at the expense of functions related to immunity and growth, as best exemplified by significant depressions in activities of enzymes (NaK, CaMg, T-ATP, and AKP) and expression levels of genes (Rab, eEF-2, HMGR, Rac1, SGK, Rab8, etc.). The performance status of S. mordax tends to improve by implementing a suite of less energy-costly compensatory mechanisms at various levels of biological organization when re-exposed to heatwaves. The adaptive abilities shown by S. mordax indicate that they can play a crucial role in the restoration of oyster reefs in tropical seas.
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  • 文章类型: Journal Article
    激光照明装置,包括紫外(UV)激光器芯片和磷光体材料,已经成为产生高亮度光源的高效方法。然而,激光激发的高功率密度可能会加剧传统多晶或非晶磷光体的热猝灭,导致发光饱和和设备的最终故障。这里,第一次,考虑到没有分散电子和声子的晶界,我们提出了一种用于激光照明的单晶(SC)材料,实现高热导率(0.81Wm-1K-1)和耐热性(575°C)。SCs产品具有高光致发光量子产率(89%)以及对高功率激光器(>12.41kW/cm2)的优异稳定性,优于所有以前报道的无定形或多晶基质。最后,激光照明装置是通过将SC与UV激光芯片(50mW)组装而成的,即使连续运行4小时,该器件也能保持其性能。掺杂有Yb3+/Er3+的双钙钛矿单晶在355和980nm激光的照射下表现出多峰发光,分别。此特性对于光谱可调激光照明和多模态防伪应用具有重要意义。
    Laser lighting devices, comprising an ultraviolet (UV) laser chip and a phosphor material, have emerged as a highly efficient approach for generating high-brightness light sources. However, the high power density of laser excitation may exacerbate thermal quenching in conventional polycrystalline or amorphous phosphors, leading to luminous saturation and the eventual failure of the device. Here, for the first time, we raise a single-crystal (SCs) material for laser lighting considering the absence of grain boundaries that scatter electrons and phonons, achieving high thermal conductivity (0.81 W m-1 K-1) and heat-resistance (575 °C). The SCs products exhibit a high photoluminescence quantum yield (89%) as well as excellent stability toward high-power lasers (>12.41 kW/cm2), superior to all previously reported amorphous or polycrystalline matrices. Finally, the laser lighting device was fabricated by assembling the SC with a UV laser chip (50 mW), and the device can maintain its performance even after continuous operation for 4 h. Double perovskite single crystals doped with Yb3+/Er3+ demonstrated multimodal luminescence with the irradiation of 355 and 980 nm lasers, respectively. This characteristic holds significant promise for applications in spectrally tunable laser lighting and multimodal anticounterfeiting.
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  • 文章类型: Journal Article
    本研究通过大气和室温等离子体(ARTP)突变优化了羊肚菌(Mel-7)菌丝体的诱变过程,并探讨了突变菌株的热适应性和生理反应。这项研究证明了ARTP诱变暴露持续时间和致死率之间的明确关系,表明40s的暴露时间导致诱导突变的最佳平衡,而不会导致过度死亡。此外,本研究将43°C作为鉴定耐热性增强的突变菌株的理想筛选温度,因为这个温度显着挑战菌丝体,同时允许耐热菌株是可区分的。在筛选的突变体中,菌株L21、L23、L44和L47表现出优异的生长和高温耐受性,在30°C时具有显著的弹性,突出了它们对高于最佳温度的适应性。此外,这项研究深入研究了生化反应,包括脂质过氧化和非酶抗氧化剂含量,突出多样化的机制,如增强的抗脂质过氧化能力和增加的抗氧化剂含量,被突变菌株用来适应温度波动。抗氧化酶的活性,包括过氧化物酶(POD)和超氧化物歧化酶(SOD),被证明受温度升高的影响很大,说明了它们在突变菌株的热适应中的关键作用。这些发现揭示了在开发具有潜在应用于各种行业的耐热性真菌菌株中考虑突变持续时间和温度筛选的重要性。本研究的突破在于全面了解了Mel-7菌丝体的热适应性,为学术和工业目的提供有价值的见解。
    This study focuses on optimizing the mutagenesis process for Morchella eximia (Mel-7) mycelia through atmospheric and room temperature plasma (ARTP) mutation and explores the resultant thermal adaptability and physiological responses of mutant strains. This research demonstrated a clear relationship between ARTP mutagenesis exposure duration and lethality rate, indicating that an exposure time of 40 s resulted in the optimal balance of inducing mutations without causing excessive mortality. Additionally, this study established 43 °C as the ideal screening temperature for identifying mutant strains with enhanced heat resistance, as this temperature significantly challenges the mycelia while allowing thermotolerant strains to be distinguishable. Among the screened mutants, strains L21, L23, L44, and L47 exhibited superior growth and high-temperature tolerance, with notable resilience at 30 °C, highlighting their enhanced adaptability to above-optimal temperatures. Furthermore, this research delved into biochemical responses, including lipid peroxidation and non-enzymatic antioxidant content, highlighting the diverse mechanisms, such as enhanced lipid peroxidation resistance and increased antioxidant content, employed by mutant strains to adapt to temperature fluctuations. The activities of antioxidant enzymes, including peroxidase (POD) and superoxide dismutase (SOD), were shown to be significantly influenced by temperature elevations, illustrating their critical roles in the thermal adaptation of mutant strains. These findings shed light on the importance of considering mutation duration and temperature screening in the development of thermotolerant fungal strains with potential applications in various industries. This study\'s breakthrough lies in its comprehensive understanding of the thermal adaptability of Mel-7 mycelia and the identification of promising mutant strains, offering valuable insights for both academic and industrial purposes.
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  • 文章类型: Journal Article
    利用牡丹在高温胁迫下成熟叶片的RNA-Seq和基因表达数据,探索牡丹耐热性的关键基因。采用加权基因共表达网络分析(WGCNA)方法构建网络,根据基因表达和模块功能富集分析结果筛选共表达的主要模块和核心基因。根据基因表达的相关性,网络分为19个模块。通过分析各模块基因的表达模式,蓝色,鲑鱼和黄是牡丹热响应相关功能的关键模块。对三个模块中的基因进行GO和KEGG功能富集分析,并构建网络图。基于此,挖掘了两个关键基因PsWRKY53(TRINITY_DN60998_c1_g2,TRINITY_DN71537_c0_g1)和PsHsfB2b(TRINITY_DN56794_c0_g1),这可能在牡丹的热休克反应中起关键作用。这3个共表达模块和2个关键基因有助于进一步阐明苦瓜的耐热机制。
    The RNA-Seq and gene expression data of mature leaves under high temperature stress of Paeonia suffruticosa \'Hu Hong\' were used to explore the key genes of heat tolerance of peony. The weighted gene co-expression network analysis (WGCNA) method was used to construct the network, and the main modules and core genes of co-expression were screened according to the results of gene expression and module function enrichment analysis. According to the correlation of gene expression, the network was divided into 19 modules. By analyzing the expression patterns of each module gene, Blue, Salmon and Yellow were identified as the key modules of peony heat response related functions. GO and KEGG functional enrichment analysis was performed on the genes in the three modules and a network diagram was constructed. Based on this, two key genes PsWRKY53 (TRINITY_DN60998_c1_g2, TRINITY_DN71537_c0_g1) and PsHsfB2b (TRINITY_DN56794_c0_g1) were excavated, which may play a key role in the heat shock response of peony. The three co-expression modules and two key genes were helpful to further elucidate the heat resistance mechanism of P. suffruticosa \'Hu Hong\'.
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  • 文章类型: Journal Article
    制备具有高力学性能和耐热性的生物基聚乳酸(PLA)泡沫材料对环境保护和绿色可持续发展具有重要意义。在本文中,首次将含有六个羟基的D-山梨醇(DS)引入聚(1-丙交酯)(PLLA)/聚(d-丙交酯)(PDLA)共混物中,以促进立体络合物(SC)晶体的形成,能改善聚乳酸泡沫塑料的发泡行为,提高其力学性能和耐热性。结果表明,DS可以通过增强对映体分子链之间的氢键作用来提高SC晶体的形成效率和结晶度。此外,与纯PLLA泡沫相比,PLLA/PDLA/DS共混泡沫的压缩模量和相互作用维卡软化温度增加了约854%和16%,分别。此外,当引入退火工艺时,PLA泡沫的压缩和耐热性进一步提高。该研究为制备具有优异的抗压和耐热性能的生物基和可生物降解PLA泡沫提供了可行的策略。
    The preparation of bio-based poly(lactic acid) (PLA) foams with high mechanical properties and heat resistance is of great significance for environmental protection and green sustainable development. In this paper, D-sorbitol (DS) containing six hydroxyl groups was introduced into poly(l-lactide) (PLLA)/poly(d-lactide) (PDLA) blends for first time to promote the formation of stereocomplex (SC) crystals, which could improve the foaming behavior and enhance mechanical properties and heat resistance of PLA foams. The results showed that DS could improve the formation efficiency and crystallinity of SC crystals by enhancing the hydrogen bonding between the enantiomeric molecular chains. Furthermore, the compression modulus and interactions Vicat softening temperature of the PLLA/PDLA/DS blend foam increased about 854% and 16% compared to the pure PLLA foam, respectively. Besides, when the annealing process was introduced, the compression and heat resistance of the PLA foams increased further. This study provided a feasible strategy for the preparation of bio-based and biodegradable PLA foams with outstanding compressive and heat resistance properties.
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  • 文章类型: Journal Article
    专用环氧树脂,能够实现室温深度固化和长时间暴露在高温环境中,作为包括航空航天在内的现代高端制造业的关键材料,船用设备制造,机械生产,和电子工业。在这里,硅杂化环氧树脂,适合室温固化,专为高温应用而设计,是使用溶胶-凝胶法合成的,硅酸酯和硅烷偶联剂作为硅源。树脂表征表明硅元素在获得的硅杂化环氧树脂中均匀分布。与非杂化环氧树脂相比,在室温固化性能方面观察到显著的改善,耐热性,和机械强度。
    Specialized epoxy resin, capable of achieving room-temperature profound curing and sustaining prolonged exposure to high-temperature environments, stands as a pivotal material in modern high-end manufacturing sectors including aerospace, marine equipment fabrication, machinery production, and the electronics industry. Herein, a silicon-hybridized epoxy resin, amenable to room-temperature curing and designed for high-temperature applications, was synthesized using a sol-gel methodology with silicate esters and silane coupling agents serving as silicon sources. Resin characterization indicates a uniform distribution of silicon elements in the obtained silicon hybrid epoxy resin. In comparison to the non-hybridized epoxy resin, notable improvements are observed in room-temperature curing performance, heat resistance, and mechanical strength.
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