Saponin 15%~20% content in the seed cake of Camellia oleifera Abel, from which Camellia oil is squeezed, is a natural nonionic surface active agent and is extensively applied to emulsification, ...humectation, foaming, medicine, pesticide, and so on. In this paper, the extraction process of saponin was researched through a combining method of alkali solution and acid isolation. A quantitative method for saponin was established by ultraviolet spectrophotometer. The influence of extraction factors was investigated by a single-factor test and a response surface methodology. The results indicated that the optimal extraction conditions of saponin were extraction temperature 68°C, alkali solution pH 9.1, acid isolation pH 4.1, and liquid-solid ratio 15.9 : 1. The extraction rate of saponin was 76.12% at the optimal extraction conditions.
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•A superior phosphate scavenger was designed deriving from La-MOF.•The adsorbent has a hierarchical structure of microsphere-nanorod-nanoparticle.•A high adsorption capacity and a ...high P/La ratio were obtained concurrently.•The adsorbent exhibits a much higher adsorption capacity of over 170mgP/g.
Excessive phosphate in water can cause severe water quality problems owing to its somatotrophic effect on microorganisms. Herein, a superstructural phosphate scavenger, La-MOF-500, composed of La2O2CO3, is rationally designed by derivation from lanthanum metal organic frameworks (La(1,3,5-BTC)(H2O)6) by calcination. La-MOF-500 has a hierarchical micro/nano structure of microsphere-nanorod-nanoparticle: urchin-like microsphere is comprised of many nanorods and the individual nanorod was formed by piling up plentiful thin nanoparticles. The hierarchical micro/nano structure provides La-MOF-500 with an intriguing phosphate capture capacity of 173.8mgP/g and a high utilization of lanthanum active sites, simultaneously, which was a challenge in previous research. Moreover, La-MOF-500 exhibits a good tolerance of foreign species. Even in the water from Songhua River (China), La-MOF-500 can remove phosphate to be less than 10μgP/L. This development is expected to be meaningful for practical water purification.
Free cooling of data centers: A review Zhang, Hainan; Shao, Shuangquan; Xu, Hongbo ...
Renewable & sustainable energy reviews,
07/2014, Letnik:
35
Journal Article
Recenzirano
The growing demand for electricity and the increasing size of the carbon footprint of data centers worldwide bring a severe challenge to sustainable development of human civilization. The cooling ...energy consumption takes up around 30–50% of the total consumption of data centers due to the inefficient cooling system. Free cooling is an effective solution for reducing the power consumption of cooling systems. This paper reviews the advancements of data center free cooling mainly focusing on configuration features and performances. Three kinds of free cooling methods, airside free cooling, waterside free cooling and heat pipe free cooling are discussed and performance characteristics of each are analyzed. Further, the criteria of performance evaluation for free cooling of data centers are summarized, and an overview of free cooling systems based on these criteria is demonstrated in order to help researchers acquire the latest developments in this area.
Precise optical and thermal regulatory systems are found in nature, specifically in the microstructures on organisms’ surfaces. In fact, the interaction between light and matter through these ...microstructures is of great significance to the evolution and survival of organisms. Furthermore, the optical regulation by these biological microstructures is engineered owing to natural selection. Herein, the role that microstructures play in enhancing optical performance or creating new optical properties in nature is summarized, with a focus on the regulation mechanisms of the solar and infrared spectra emanating from the microstructures and their role in the field of thermal radiation. The causes of the unique optical phenomena are discussed, focusing on prevailing characteristics such as high absorption, high transmission, adjustable reflection, adjustable absorption, and dynamic infrared radiative design. On this basis, the comprehensive control performance of light and heat integrated by this bioinspired microstructure is introduced in detail and a solution strategy for the development of low‐energy, environmentally friendly, intelligent thermal control instruments is discussed. In order to develop such an instrument, a microstructural design foundation is provided.
Precise optical and thermal regulatory systems are found in nature, specifically in the microstructures on organisms’ surfaces. The comprehensive control performance of light and heat integrated by these bioinspired microstructures is introduced and a solution strategy for the development of low‐energy, environmentally friendly, intelligent thermal control instruments is provided.
Fluorescent graphene quantum dots (GQDs) have attracted tremendous attention because of their unique 2D layered structure, large surface area, good water solubility, tunable fluorescence, high ...photostability, excellent biocompatibility and low toxicity, which make them promising candidates for applications in various fields. In this review, we summarize the latest progress in research on GQDs, focusing on their preparation
via
both top-down and bottom-up routes and application in fluorescence sensing of inorganic ions, organic molecules and biomaterials. This review provides insight into GQDs to inspire their further development, including their controllable preparation and use in a wider range of sensing applications, by the large community of researchers focusing on graphene.
This paper reviews recent activities in the preparation and fluorescence sensing applications of graphene quantum dots.
Background and Aims
Itaconate, a metabolite of the tricarboxylic acid cycle, plays anti‐inflammatory roles in macrophages during endotoxemia. The mechanisms underlying its anti‐inflammatory roles ...have been shown to be mediated by the modulation of oxidative stress, an important mechanism of hepatic ischemia–reperfusion (I/R) injury. However, the role of itaconate in liver I/R injury is unknown.
Approach and Results
We found that deletion of immune‐responsive gene 1 (IRG1), encoding for the enzyme producing itaconate, exacerbated liver injury and systemic inflammation. Furthermore, bone marrow adoptive transfer experiments indicated that deletion of IRG1 in both hematopoietic and nonhematopoietic compartments contributes to the protection mediated by IRG1 after I/R. Interestingly, the expression of IRG1 was up‐regulated in hepatocytes after I/R and hypoxia/reoxygenation‐induced oxidative stress. Modulation of the IRG1 expression levels in hepatocytes regulated hepatocyte cell death. Importantly, addition of 4‐octyl itaconate significantly improved liver injury and hepatocyte cell death after I/R. Furthermore, our data indicated that nuclear factor erythroid 2–related factor 2 (Nrf2) is required for the protective effect of IRG1 on mouse and human hepatocytes against oxidative stress–induced injury. Our studies document the important role of IRG1 in the acute setting of sterile injury induced by I/R. Specifically, we provide evidence that the IRG1/itaconate pathway activates Nrf2‐mediated antioxidative response in hepatocytes to protect liver from I/R injury.
Conclusions
Our data expand on the importance of IRG1/itaconate in nonimmune cells and identify itaconate as a potential therapeutic strategy for this unfavorable postsurgical complication.
Recently, metal-organic frameworks (MOFs) and their carbon derivates have been demonstrated as new electrode modifying materials for electrochemical sensing. In this work, the first example of the ...detection of heavy metal ions with a MOF-derived sensing platform was presented. The platform was based on a glassy carbon electrode (GCE) modified by Nafion-bismuth/nitrogen doped microporous carbon (NMC) composite, in which the NMC was derived from a zeolitic imidazolate framework-8 (ZIF-8). The good dispersibility, large specific surface area (941 m2g−1), high nitrogen content (25.0 at.%) and good electrical conductivity of the NMC materials, as well as the synergistic effects of Nafion and bismuth-film contributed to the enhanced signals of the electrode during the differential pulse anodic stripping voltammetry (DPASV) measurements for simultaneous detection of trace Cd(II) and Pb(II) in aqueous solution. The calibration curves for Cd(II) covered two linear ranges varying from 2 to 10μgL−1 and 10 to 100μgL−1. As for Pb(II), the linear calibration curves ranged from 0.5 to 10μgL−1 and 10 to 100μgL−1. The detection limits were estimated to be 1.5μgL−1 (S/N=3) for Cd(II) and 0.05μgL−1 (S/N=3) for Pb(II), which were 2 times and 200 times lower than the guideline values of drinking water given by the World Health Organization (WHO), for Cd(II) and Pb(II), respectively. In addition, the good reproducibility and stability of the modified electrode offered a promising perspective for the detection of trace metal ions in practice. Compared with other porous carbon modified electrodes that obtained by either drop-casting or screen-printing method, the proposed Nafion/Bi/NMC/GCE showed a much lower detection limit for Pb(II) and a lower or comparable detection limit for Cd(II). Moreover, the obtaining of uniformly ordered N-doped carbon polyhedron could shed light on the preparation of other heteroatom-doped electrode modifying materials for the detection of heavy metal ions.
In this letter, we consider a downlink non-orthogonal multiple access (NOMA) system where a base station (BS) simultaneously communicates with multiple users. These users are grouped on multiple ...unequal-bandwidth subchannels. The power and bandwidth allocation are jointly optimized in order to maximize the system energy efficiency (EE) under transmit power constraint at the BS and minimum rate constraints for individual users. The optimization problem is nonconvex because of the fractional objective function and the nonconvex constraints. To deal with the original problem, it is first converted into an equivalent DC (difference of two convex functions) program by introducing slack variables, and then an iterative algorithm based on the constrained concave-convex procedure is proposed to solve it. Our numerical results demonstrate that the proposed algorithm has better EE performance compared to the NOMA scheme with equal-bandwidth allocation and conventional orthogonal multiple access scheme.
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•Affected by natural and economic factors, there are differences in the value of ecosystem services and expanded built-up land in China between North and South.•The multi-regional ...input–output (MRIO) model is used to quantify virtual land transfer among regions.•Part of expanded built-up land serves external regions, with build-up land and ecological costs shifting from south to north.•Economically developed regions dominate regional trade, and regional inequities exist in a few regions.
During rapid economic development and urbanisation, land expansion in built-up areas is China's dominant land-use change type, resulting in the loss of ecosystem service value (ESV). Economic development is China's main driving force for built-up land expansion. Under the trend of the spatial separation of production and consumption, expanded built-up land embodied in trade flows between regions as a scarce land resource. Through trade, a region can indirectly use built-up land from outside areas, which may affect land use within the user and provider regions. Regional ESV loss may be affected by outer regions, although previous studies have seldom considered it. Accordingly, this study quantified ESV for the whole of China in high resolution and determined ESV loss caused by expanded built-up land for each province and ESV loss flows embodied in interregional interactions. The results found that China's total ESV of terrestrial ecosystems was 37.44 trillion yuan in 2015, and the expanded built-up land resulted in a loss of 13.7 billion yuan in ESV. Due to the north–south differences in natural and economic levels in China, there was significant spatial heterogeneity in ESV and ESV loss caused by built-up land expansion, with the high-value areas mainly in the southern coastal areas. With regional interaction, the leading regional flow direction of built-up land and ESV loss was from north to south, mainly from economically developing regions to economically developed regions. However, there was a discrepancy between the actual users of the built-up land and the ESV loss-bearers. Evident regional inequalities existed in several provinces with regional interactions. Overall, this study provides a reference for developing China's interregional economic and ecological harmony strategies in the context of sustainable development.
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