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1.
Zhenzhen Hao Xiaolu Wang Haomeng Yang Tao Tu Jie Zhang Huiying Luo Huoqing Huang Xiaoyun Su 《International journal of molecular sciences》2021,22(6)
Plant cell wall polysaccharides (PCWP) are abundantly present in the food of humans and feed of livestock. Mammalians by themselves cannot degrade PCWP but rather depend on microbes resident in the gut intestine for deconstruction. The dominant Bacteroidetes in the gut microbial community are such bacteria with PCWP-degrading ability. The polysaccharide utilization systems (PUL) responsible for PCWP degradation and utilization are a prominent feature of Bacteroidetes. In recent years, there have been tremendous efforts in elucidating how PULs assist Bacteroidetes to assimilate carbon and acquire energy from PCWP. Here, we will review the PUL-mediated plant cell wall polysaccharides utilization in the gut Bacteroidetes focusing on cellulose, xylan, mannan, and pectin utilization and discuss how the mechanisms can be exploited to modulate the gut microbiota. 相似文献
2.
《Ceramics International》2021,47(19):26891-26897
KLS-1 Lunar regolith simulant was microwave sintered to explore its potential applicability in future lunar construction. The effects of sintering temperature on linear shrinkage, density, porosity, and microstructural, mechanical, and thermal properties were investigated. As the sintering temperature increased, linear shrinkage and density increased and porosity decreased. Structural evolution in the sintered samples was characterized by scanning electron microscopy and X-ray diffraction. Unconfined compressive strength testing showed that mechanical strength increased significantly with increasing sintering temperature, with 1120 °C giving the highest strength of 37.0 ± 4.8 MPa. The sintered samples exhibited a coefficient of thermal expansion of approximately 5 × 10−6 °C−1, which was well-maintained even after cyclic temperature stress between −100 and 200 °C. Therefore, this microwave processing appears promising for the fabrication of building material with sufficient mechanical strength and thermal durability for lunar construction. 相似文献
3.
Gabriel Falzone Iman Mehdipour Narayanan Neithalath Mathieu Bauchy Dante Simonetti Gaurav Sant 《American Institute of Chemical Engineers》2021,67(5):e17160
Portlandite (Ca(OH)2; also known as calcium hydroxide or hydrated lime), an archetypal alkaline solid, interacts with carbon dioxide (CO2) via a classic acid–base “carbonation” reaction to produce a salt (calcium carbonate: CaCO3) that functions as a low-carbon cementation agent, and water. Herein, we revisit the effects of reaction temperature, relative humidity (RH), and CO2 concentration on the carbonation of portlandite in the form of finely divided particulates and compacted monoliths. Special focus is paid to uncover the influences of the moisture state (i.e., the presence of adsorbed and/or liquid water), moisture content and the surface area-to-volume ratio (sa/v, mm−1) of reactants on the extent of carbonation. In general, increasing RH more significantly impacts the rate and thermodynamics of carbonation reactions, leading to high(er) conversion regardless of prior exposure history. This mitigated the effects (if any) of allegedly denser, less porous carbonate surface layers formed at lower RH. In monolithic compacts, microstructural (i.e., mass-transfer) constraints particularly hindered the progress of carbonation due to pore blocking by liquid water in compacts with limited surface area to volume ratios. These mechanistic insights into portlandite's carbonation inform processing routes for the production of cementation agents that seek to utilize CO2 borne in dilute (≤30 mol%) post-combustion flue gas streams. 相似文献
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乡村产业中的化石能源设备逐渐被电能技术替代,引起了乡村负荷波动增大、部分时段产生集中高负荷的问题。为了解决以上问题,将低品位清洁能源应用至乡村的茶叶生产中,针对烘茶全过程的工艺要求提出了跨临界CO2热泵烘茶技术;并以某茶叶生产乡村为对象,对其代表台区的全年日用电量及产茶日负荷进行了分析,得出采用CO2热泵烘茶后其负荷得到大幅度削减,整体可降低至原负荷的39.6%~46.8%,峰值负荷与平时负荷的比值由原本的13.6降至5.4~6.2。跨临界CO2热泵应用至农产品生产中可有效缓解乡村供电压力。 相似文献
7.
Roselle Barretto Rania Marie Buenavista Jared Lou Rivera Shuyu Wang P.V. Vara Prasad Kaliramesh Siliveru 《International Journal of Food Science & Technology》2021,56(7):3125-3137
The demand for food production has been constantly increasing due to rising population. In developed countries, for example, the emergence of regional production of old grains that are rarely utilized, along with the production of commonly consumed grains, has gained importance in recent years. These grains, known collectively as ancient or heirloom grains, have offered both farmers and consumers novel ways of cultivation and products with interesting taste, characteristics and nutritional value. Among the 30 000 plant species known, only five cereals currently provide more than 50% of the world's energy intake – bread wheat (Triticum aestivum), rice (Oryza sativa), sorghum (Sorghum bicolor), millets (Panicum sp.) and maize (Zea mays). The excessive utilization of these selected species has a great potential to cause genetic losses and difficulty in bridging future agricultural demands. Teff (Eragrostis tef), an ancient grain extensively cultivated in countries like Eritrea and Ethiopia, provides promising alternatives for new food uses since its nutritional value is significantly higher than most others cereal grains. The absence of gluten allows flexibility in food utilization since it can be directly substituted to gluten-containing products. The grain also offers an excellent balance of essential amino acids and minerals, which can fulfil the recommended daily intake and eliminates the need for fortification and enrichment. This review provides a general overview of the physical properties and nutritional composition of teff grains related to processing and applications in the food and feed industries. The current status of teff utilization, as well as the challenges in production and commercialization, and future opportunities is presented and discussed. 相似文献
8.
星地一体化网络是卫星网络和地面网络互联,实现卫星网络和地面网络优势互补的一体化网络。随着无线通信的快速发展,卫星网络和地面网络的同频复用技术可有效提升资源利用效率,满足日益增长的无线数据业务需求。但由于无线数据业务类型的多样化和频谱资源的稀缺性,如何实现用户数据服务的服务体验质量(Quality of experience, QoE)和公平性提升也成为星地一体化网络亟待解决的关键问题。本文综合考虑信道时变性、服务体验多样性和服务公平性,提出了一种基于QoE感知的星地一体化网络资源分配策略。为此,将目标问题描述为基于时间平均的服务体验质量的网络公平效用最大化,并利用李雅普诺夫优化理论,将复杂的动态原始优化问题进一步转化并分解为3个瞬时优化子问题,每个子问题可以在每个时隙独立求解。同时,由于无线资源分配为典型的非凹混合组合优化问题,推导了一个低复杂度的两步算法来求解第三个资源分配子问题。仿真结果揭示了在不同的公平性参数下用户的长时QoE与公平性之间的折衷情况。 相似文献
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本文使用Prophet人工智能算法研究与预测移动通信网络“潮汐效应”现象,探索网络“潮汐效应”在优化网络资源配置实现网络降本增效的作用。Prophet人工智能算法是一种简单、有效,且易于实现的人工智能算法。通过facebook的人工智能开源框架fbprophet,研究4G网络PRB利用率等网络资源指标的“潮汐效应”,并预测这些网络资源指标在未来的变化趋势,用来指导当前4G网络减容、扩容和4/5G节电节能等,实现优化网络资源配置达到降本增效的目的。 相似文献