The increasing importance of lignocellulosic biomass as a renewable energy source has led to an acute need for reliable and detailed information on its assessment, consumption and supply. With the ...passage of China’s legislative targets for renewable portfolio standards, agricultural residue resources have the potential for an increasing role in meeting liquid fuels demand in China. An assessment of current and near future agricultural residue resources (including agricultural crop residues and secondary agricultural processing residues) in China at national scale was conducted. This paper gave the theoretical quantity, collectable quantity, usable quantity and potential quantity for liquid biofuel production of agricultural residues in China. The spatial and seasonal distributions of crop residues were analyzed. The theoretical output of crop residues in China at national scale in the near future were forecasted by means of an artificial neural network (ANN) model. The availability of agricultural residues in China was presented, as a result, the potential of liquid biofuels from agricultural residues was discussed. The ANN predicted results have shown that the theoretical output of crop residues in China at national scale will be up to 930.8 million tons in 2015. About 44 million tons per year of bioethanol or 131 million tons per year of bio-oil would have been produced, if the total usable output of agricultural crop residues were used to produce bioethanol through biochemical conversion process or bio-oil through fast pyrolysis, which could replace 26.9 million tons of gasoline or 58.2 million tons of diesel at national scale in 2015, respectively. The above results will be helpful for commercialization of bioenergy industry and their market-oriented development strategy, so as to accelerate the development of industrialization of biofuel technologies.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Vibration of fluid-conveying pipes is isolated by quasi-zero stiffness systems.•Nonlinear solution is obtained via Galerkin method and the finite difference.•The fluid flow can deteriorate the ...performance of vibration isolation.
Fluid-conveying pipes are always subjected to various excitations to cause unwanted vibrations. A quasi-zero stiffness system consisting of three linear springs is adopted as the nonlinear isolator to attenuate the transverse vibrations of fluid-conveying pipes induced by foundation excitations. A dynamic model of nonlinear forced vibration of the fluid-conveying pipe coupled with two nonlinear isolators is established for the nonlinear continuous system and validated by using two methods, Galerkin method and the finite difference method. The influence of the quasi-zero stiffness isolators on the vibration characteristics and vibration transmission of the pipe is investigated by analyzing the natural frequency, vibration mode, and nonlinear vibration response. The effects of flow speed of the fluid and the system parameters of the isolator are studied to evaluate the isolation performance. It is found that the quasi-zero stiffness isolator and fluid flow can shift several natural frequencies of vibration of the pipeline to the low-frequency region. When the linear stiffness of the vibration isolation is zero in the vertical direction, the first two modes of the bending vibration of the fluid-conveying pipe tend to become rigid mode. While achieving high-efficiency vibration isolation in the high-frequency region, the vibration in the low-frequency region is complicated. The flow speed of the fluid can deteriorate the performance of vibration isolation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Wuhan was the first epicentre of COVID-19 in the world, accounting for 80% of cases in China during the first wave. We aimed to assess household transmissibility of severe acute respiratory syndrome ...coronavirus 2 (SARS-CoV-2) and risk factors associated with infectivity and susceptibility to infection in Wuhan.
This retrospective cohort study included the households of all laboratory-confirmed or clinically confirmed COVID-19 cases and laboratory-confirmed asymptomatic SARS-CoV-2 infections identified by the Wuhan Center for Disease Control and Prevention between Dec 2, 2019, and April 18, 2020. We defined households as groups of family members and close relatives who did not necessarily live at the same address and considered households that shared common contacts as epidemiologically linked. We used a statistical transmission model to estimate household secondary attack rates and to quantify risk factors associated with infectivity and susceptibility to infection, accounting for individual-level exposure history. We assessed how intervention policies affected the household reproductive number, defined as the mean number of household contacts a case can infect.
27 101 households with 29 578 primary cases and 57 581 household contacts were identified. The secondary attack rate estimated with the transmission model was 15·6% (95% CI 15·2–16·0), assuming a mean incubation period of 5 days and a maximum infectious period of 22 days. Individuals aged 60 years or older were at a higher risk of infection with SARS-CoV-2 than all other age groups. Infants aged 0–1 years were significantly more likely to be infected than children aged 2–5 years (odds ratio OR 2·20, 95% CI 1·40–3·44) and children aged 6–12 years (1·53, 1·01–2·34). Given the same exposure time, children and adolescents younger than 20 years of age were more likely to infect others than were adults aged 60 years or older (1·58, 1·28–1·95). Asymptomatic individuals were much less likely to infect others than were symptomatic cases (0·21, 0·14–0·31). Symptomatic cases were more likely to infect others before symptom onset than after (1·42, 1·30–1·55). After mass isolation of cases, quarantine of household contacts, and restriction of movement policies were implemented, household reproductive numbers declined by 52% among primary cases (from 0·25 95% CI 0·24–0·26 to 0·12 0·10–0·13) and by 63% among secondary cases (from 0·17 0·16–0·18 to 0·063 0·057–0·070).
Within households, children and adolescents were less susceptible to SARS-CoV-2 infection but were more infectious than older individuals. Presymptomatic cases were more infectious and individuals with asymptomatic infection less infectious than symptomatic cases. These findings have implications for devising interventions for blocking household transmission of SARS-CoV-2, such as timely vaccination of eligible children once resources become available.
National Natural Science Foundation of China, Fundamental Research Funds for the Central Universities, US National Institutes of Health, and US National Science Foundation.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Understanding ecological niches of major tick species and prevalent tick-borne pathogens is crucial for efficient surveillance and control of tick-borne diseases. Here we provide an up-to-date review ...on the spatial distributions of ticks and tick-borne pathogens in China. We map at the county level 124 tick species, 103 tick-borne agents, and human cases infected with 29 species (subspecies) of tick-borne pathogens that were reported in China during 1950-2018. Haemaphysalis longicornis is found to harbor the highest variety of tick-borne agents, followed by Ixodes persulcatus, Dermacentor nutalli and Rhipicephalus microplus. Using a machine learning algorithm, we assess ecoclimatic and socioenvironmental drivers for the distributions of 19 predominant vector ticks and two tick-borne pathogens associated with the highest disease burden. The model-predicted suitable habitats for the 19 tick species are 14‒476% larger in size than the geographic areas where these species were detected, indicating severe under-detection. Tick species harboring pathogens of imminent threats to public health should be prioritized for more active field surveillance.
In solid propellants, aluminum plays a key role in energy performance enhancement, but it also induces combustion problems such as low combustion efficiency and agglomeration. Herein, we study the ...effects of Al on the combustion properties of low-signal composite-modified double-base (CMDB) propellants. Experiments were conducted to determine the heat of explosion, the burning rates, and the combustion wave structures. The flame structure, the burning surface phenomenon and the morphology of the extinguished surface layer were observed. In addition, distribution of Al particles was calculated. It was found that using small Al particles or lowering the Al content will reduce the burning rate. This result was mainly cause by the “thermal sink” effect of Al. The Al agglomeration and ignition behaviors in the dark zone and the flame zone were observed at 1 and 3 MPa. It was found that propellants containing more than 10 wt.% Al or using Al particles smaller than 5 µm tended to generate large Al agglomerates. The extinguished burning surface presented “metal skeleton” structure under low pressures. The Al particles smaller than the HMX would be locally concentrated, so that it was easier for them to form large agglomerates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Agricultural residues are readily available and inexpensive renewable resources in China and can be utilized for reducing China’s reliance on fossil fuels and CO
2
emissions. This study conducted a ...systematic study of energy production and consumption, CO
2
emissions, and agricultural residues available for energy and environmental benefits in China. The gap between the domestic production and consumption of energy in China was large. China’s energy consumption structure was dominated by coal over the past thirty years, which was strongly linked the increasing CO
2
emissions in China. China has abundant agricultural residues resource, most of which were utilized as soil amendments, animal feeds, substrates in mushroom cultivation, and industrial materials. The usable agricultural residues for energy were estimated to be about 226.9 million tons in 2020. If those usable agricultural residues would be converted into bio-oil and biochar through pyrolysis, it could not only replace about 102 million tons of crude oil, but also sequestrate about 209 million tons of CO
2
-equivalent. It is expected that the results from this study can promote the application of agricultural residues in potential of energy production and carbon sequestration.
Statement of Novelty
In this study, the energy production and consumption, CO
2
emissions, and pyrolysis conversion of agricultural residues resources for energy and environmental benefits in China were comprehensively investigated. The highlights are listed as follows: (1) Gap between energy production and consumption in China became larger and larger; (2) CO
2
emissions has significantly increased by three times during the past three decades; (3) Total collectable agricultural residues annually reached 0.96 billion tons; (4) Usable agricultural residues for energy annually reached 227 million tons; (5) Pyrolysis of agricultural residues is effective for energy and environmental benefits.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Nitrile hydratase (NHase), an excellent bio-catalyst for the synthesis of amide compounds, was composed of two heterologous subunits. A thermoalkaliphilic NHase NHCTA1 (Tm = 71.3°C) obtained by in ...silico screening in our study exhibited high flexibility of α-subunit but excellent thermostability, as opposed to previous examples. To gain a deeper structural insight into the thermostability of NHCTA1, comparative molecular dynamics simulation of NHCTA1 and reported NHases was carried out. By comparison, we speculated that β-subunit played a key role in adjusting the flexibility of α-subunit and the different conformations of linker in "α5-helix-coil ring" supersecondary structure of β-subunit can affect the interaction between β-subunit and α-subunit. Mutant NHCTA1-α
C with a random coil linker and mutant NHCTA1-αβγ with a truncated linker were therefore constructed to understand the impact on NHCTA1 thermostability by varying the supersecondary structure. The varied thermostability of NHCTA1-α
C and NHCTA1-αβγ (Tm
= 74.4°C, Tm
= 65.6°C) verified that the flexibility of α-subunit adjusted by β-subunit was relevant to the stability of NHCTA1. This study gained an insight into the NNHCTA1 thermostability by virtual dynamics comparison and experimental studies without crystallization, and this approach could be applied to other industrial-important enzymes.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The phosphorylation of STAT3 plays a critical physiological role in the proliferation of rectal cancer. Hence, inhibiting STAT3 phosphorylation is an effective anticancer approach. In this work, we ...designed a novel 5‐R'‐1‐naphthylmethylamide scaffold as a small molecule inhibitor of STAT3 phosphorylation. The results showed that 3D and 4D have exceptional inhibitory ability against three different colorectal cancer (CRC) cell lines, and can induce apoptosis of CRC cells by inhibiting STAT3 phosphorylation, while having no killing effect on normal human cells. 3D and 4D can inhibit STAT3 phosphorylation in a time‐ and concentration‐dependent manner, and also inhibit the nuclear translocation of interleukin (IL)‐6‐induced STAT3. In the in vivo tumor model research, 4D significantly reduced the tumor volume of mice and had no drug toxicity on other organ tissues. Furthermore, molecular docking studies revealed that 3D and 4D had greater binding free energy when interacting with the STAT3 SH2 structural domain, and could establish H–π interaction modes. Dynamic simulation studies indicated that both compounds were able to bind tightly to STAT3.
Based on the structures of nine existing STAT3 phosphorylation inhibitors, a novel small‐molecule compound with a simple structure was constructed. Derivative 4D exhibited good biological activity in colorectal cancer cell lines, induced apoptosis of tumor cells, and showed good bioactivity in vitro and in vivo, exerting its biological activity by inhibiting STAT3 phosphorylation. 4D also significantly reduced the tumor tissue in mouse tumor models.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Metal-organic framework Zr6O4(OH)4(BTC)2(HCOO)6 (MOF-808) nanoparticles were successfully synthesized with a household microwave oven in less than 5min of irradiation time. The obtained MOF-808 ...nanoparticles exhibited high superacidity, making them excellent adsorbent for arsenic removal. The adsorption capacity of the as-synthesized MOF-808 nanoparticles for arsenic was 24.83mg/g. Furthermore, the adsorbents still maintained 82.10% of the removal efficiency after five cycles, indicating that the MOF-808 nanoparticles can serve as a regenerable As(V) adsorbent.
MOF-808 nanocrystals have been rapidly fabricated by using microwave irradiation method, and the as-prepared MOF-808 nanocrystals exhibited high adsorption capacity for arsenic removal and excellent chemical stability and reusability. Display omitted
•MOF-808 nanocrystals were synthesized by using microwave irradiation method.•The obtained nanocrystals were employed as an adsorbent for arsenate removal.•MOF-808 nanocrystals exhibited high adsorption capability for arsenic removal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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