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•Selective catalytic reduction of NOx with NH3 over Cu/SSZ-13.•Catalysts are prepared by one-pot synthesis method with different Si/Al ratios.•Cu/SSZ-13-6.5 shows the best NH3-SCR ...performance and hydrothermal stability.•Increasing Si/Al deteriorates physical-chemical properties of aged catalysts.•Increasing Si/Al decreases active sites, nitrate species, acidity of aged catalysts.
This study focuses on investigating the influence of Si/Al ratio on the performance of hydrothermally aged Cu/SSZ-13 catalysts prepared by in situ hydrothermal synthesis method. It was found that NH3-SCR performance and hydrothermal stability of Cu/SSZ-13 decreased with increasing Si/Al ratio. Fresh and hydrothermally aged Cu/SSZ-13 with Si/Al ratio of 6.5 showed the best SCR activity and N2 selectivity in a broad temperature of 200–500 °C, in which more than 90% NOx was reduced with superior N2 selectivity above 95%. The effect of Si/Al ratio on the properties of the physicochemical structure, the change of acidity intensity, and Cu species migration or transformation of the fresh and aged Cu/SSZ-13 catalysts were comprehensively characterized by NH3-TPO, NH3-TPD, H2-TPR, N2 physisorption, XRD, ICP-AES, and XPS. The increase of the surface CuO species, the decrease of the amount of Cu2+ in active sites, the chemisorption NH3 species, the specific surface area, the total pore volume, and the increase of average pore diameter, may be the main reasons for performance deterioration over high-Si/Al-ratio catalysts after hydrothermal aging. Furthermore, in situ DRIFTS indicate that, with the increasing Si/Al ratio, the zeolitic structure was easy to collapse, and that the surface acid sites, the active copper species, as well as the adsorbed surface nitrate, decreased after hydrothermally aged. After hydrothermal aging, the amount of isolated Cu2+ decreased, and more CuO species were aggregated, mainly coming from the conversion of the unstable isolated Cu2+ species in D6R or CHA cages. The decrease of isolated Cu2+ and CuO species aggregation were significant in Cu/SSZ-13 with high Si/Al ratios. The CuO leaded to the instability of the SSZ-13 skeleton structure and NH3 oxidation promotion, resulting in catalysts deactivation.
Enzyme induced carbonate precipitation (EICP) is an emerging soil improvement method using free urease enzyme for urea hydrolysis. This method has advantages over the commonly used microbially ...induced carbonate precipitation (MICP) process as it does not involve issues related to bio-safety. However, in terms of efficiency of calcium carbonate production, EICP is considered lower than that of MICP. In this paper, a high efficiency EICP method is proposed. The key of this new method is to adopt a one-phase injection of low pH solution strategy. In this so-called one-phase-low-pH method, EICP solution consisting of a mixture of urease solution of pH = 6.5, urea and calcium chloride is injected into soil. The test results have shown that the one-phase-low-pH method can improve significantly the calcium conversion efficiency and the uniformity of calcium carbonate distribution in the sand samples as compared with the conventional two-phase EICP method. Furthermore, the unconfined compressive strength of sand treated using the one-phase-low-pH method is much higher than that using the two-phase method and the one-phase-low-pH method is also simpler and more efficient as it involves less number of injections.
A photothermal nanoconfinement reactor (PNCR) system is proposed and demonstrated by using hollow carbon nanospheres (HCNs) to enhance the performance of the chemical reaction. Under light ...irradiation, the local temperature of the HCN inner void space was much higher than the bulk solution temperature because the confined space concentrates heat and inhibits heat loss. Using the temperature‐sensitive model reaction, peroxydisulfate (PDS) activation to oxidize micropollutant, it is shown that the degradation rate of sulfamethoxazole in the PNCR system is 7.1 times of that without nanoconfinement. It is further discovered that the high‐quality local heat inside the nanoconfined space shifted the model reaction from an otherwise non‐radical pathway to a radical‐based pathway. This work provides an interesting strategy to produce a locally high temperature, which has a wide range of applications to energy and environmental fields.
A photothermal nanoconfinement reactor (PNCR) comprised of hollow carbon nanospheres boosts the overall chemical reaction rate of an otherwise large reaction volume during peroxydisulfate‐mediated oxidation of micropollutants. The reaction pathway, which would ordinarily involve radical species, is directed through a non‐radical pathway because of the local heat in the nanoconfined space.
Long-term efficacy of a hepatitis E vaccine Zhang, Jun; Zhang, Xue-Feng; Huang, Shou-Jie ...
New England journal of medicine/The New England journal of medicine,
2015-Mar-05, Letnik:
372, Številka:
10
Journal Article
Recenzirano
Odprti dostop
Hepatitis E virus (HEV) is a leading cause of acute hepatitis. The long-term efficacy of a hepatitis E vaccine needs to be determined.
In an initial efficacy study, we randomly assigned healthy ...adults 16 to 65 years of age to receive three doses of either a hepatitis E vaccine (vaccine group; 56,302 participants) or a hepatitis B vaccine (control group; 56,302 participants). The vaccines were administered at 0, 1, and 6 months, and the participants were followed for 19 months. In this extended follow-up study, the treatment assignments of all participants remained double-blinded, and follow-up assessments of efficacy, immunogenicity, and safety were continued for up to 4.5 years.
During the 4.5-year study period, 60 cases of hepatitis E were identified; 7 cases were confirmed in the vaccine group (0.3 cases per 10,000 person-years), and 53 cases in the control group (2.1 cases per 10,000 person-years), representing a vaccine efficacy of 86.8% (95% confidence interval, 71 to 94) in the modified intention-to-treat analysis, rather than (95% confidence interval, 71 to 84) corrected. Of the participants who were assessed for immunogenicity and were seronegative at baseline, 87% of those who received three doses of the hepatitis E vaccine maintained antibodies against HEV for at least 4.5 years; HEV antibody titers developed in 9% in the control group. The rate of adverse events was similar in the two groups.
Immunization with this hepatitis E vaccine induced antibodies against HEV and provided protection against hepatitis E for up to 4.5 years. (Funded by the Chinese Ministry of Science and Technology and others; ClinicalTrials.gov number, NCT01014845.).
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Creeping bentgrass (Agrostis soionifera) is a perennial grass of Gramineae, belonging to cold season turfgrass, but has poor disease resistance. Up to now, little is known about the induced systemic ...resistance (ISR) mechanism, especially the relevant functional proteins, which is important to disease resistance of turfgrass. Achieving more information of proteins of infected creeping bentgrass is helpful to understand the ISR mechanism.
With BDO treatment, creeping bentgrass seedlings were grown, and the ISR response was induced by infecting Rhizoctonia solani. High-quality protein sequences of creeping bentgrass seedlings were obtained. Some of protein sequences were functionally annotated according to the database alignment while a large part of the obtained protein sequences was left non-annotated. To treat the non-annotated sequences, a prediction model based on convolutional neural network was established with the dataset from Uniport database in three domains to acquire good performance, especially the higher false positive control rate. With established model, the non-annotated protein sequences of creeping bentgrass were analyzed to annotate proteins relevant to disease-resistance response and signal transduction.
The prediction model based on convolutional neural network was successfully applied to select good candidates of the proteins with functions relevant to the ISR mechanism from the protein sequences which cannot be annotated by database alignment. The waste of sequence data can be avoided, and research time and labor will be saved in further research of protein of creeping bentgrass by molecular biology technology. It also provides reference for other sequence analysis of turfgrass disease-resistance research.
Abstract The aim of the current study was to investigate the effects of ingesting different dosages of caffeine (CAF) prior to plyometric jump training (PJT) on sport-related performance and ...physiological parameters in male basketball players. Twenty-four young athletes were randomly divided into 3 groups and performed 6 weeks of PJT while consuming 3 mg·kg –1 of body mass caffeine (CAF3, n = 8), 6 mg·kg –1 body mass caffeine (CAF6, n = 8) or placebo (PL; n = 8) one hour prior to each training session. Before and after the 6-week PJT, the players were evaluated for field-based basketball-specific performance measures (vertical jump, 20-m sprint, Illinois change of direction speed CODS, and maximal strength) and lab-based physiological (aerobic capacity and anaerobic power) parameters. CAF3, CAF6, and PL groups demonstrated significant improvements in vertical jump (ES = 1.07, 1.45, and 1.1, respectively), 20-m sprint (ES = – 0.50, – 0.61, and – 0.36), change of direction performance (ES = – 1.22, – 1.26, and – 1.09), maximal strength (ES = 1.68, 2.29, and 1.17), maximum oxygen uptake (V̇O 2max ) (ES = 1.09, 1.59, and 0.92), and peak (ES = 1.82, 1.85, and 0.82) and average power output (ES = 1.39, 1.32, and 1.07) after 6 weeks of training. Comparative analysis of individual adaptive responses to training indicated that the CAF6 led to insignificantly greater effects in vertical jump (ES = 1.45), maximal strength (ES = 2.29), and V̇O 2max (ES = 1.59) with lower residuals in individual changes and lower coefficient of variations (CV) in mean group changes. Regarding sprint and CODS performance, both experimental groups indicated similar changes, residuals in individual changes, and CVs in mean group changes. Overall, consuming 6 mg·kg –1 body mass caffeine induces superior adaptations in aerobic fitness, anaerobic power, and sport-specific performance measures, with lower inter-individual variability in the adaptations and more homogenized changes over the training period.
Selective photoactivation of inert aryl halides is a fundamental challenge in organic synthesis. Specially, the long-wavelength red light is more desirable than the widely-applied blue light as the ...excitation source for photoredox catalysis, due to its superior penetration depth. However, the long-wavelength red light-driven photoactivation of inert aryl halides remains a challenge, mainly because of the low energy of the single long-wavelength red photon. Herein, we report the photoreduction of aryl bromides/chlorides with 656 nm LED via triplet-triplet annihilation (TTA) strategy. This method is based on our discovery that the commonly used chromophore of perylene can serve as an efficient and metal-free photocatalyst to enable the photoreduction of inert aryl halides without the conventional need for electronic sacrificial agents. By introducing a red light-absorbing photosensitizer to this perylene system, we accomplish the long-wavelength red light-driven photoreduction of aryl halides via sensitized TTA mechanism. Moreover, the performance of such a TTA-mediated photoreduction can be significantly enhanced when restricting the rotation freedom of phenyl moiety for perylene derivatives to suppress their triplet nonradiative transition, in both small and large-scale reaction settings.
Hepatocellular carcinoma (HCC) is the most common primary liver cancer and a major public health problem worldwide. Hepatocarcinogenesis is a complex multistep process at molecular, cellular, and ...histologic levels with key alterations that can be revealed by noninvasive imaging modalities. Therefore, imaging techniques play pivotal roles in the detection, characterization, staging, surveillance, and prognosis evaluation of HCC. Currently, ultrasound is the first-line imaging modality for screening and surveillance purposes. While based on conclusive enhancement patterns comprising arterial phase hyperenhancement and portal venous and/or delayed phase wash-out, contrast enhanced dynamic computed tomography and magnetic resonance imaging (MRI) are the diagnostic tools for HCC without requirements for histopathologic confirmation. Functional MRI techniques, including diffusion-weighted imaging, MRI with hepatobiliary contrast agents, perfusion imaging, and magnetic resonance elastography, show promise in providing further important information regarding tumor biological behaviors. In addition, evaluation of tumor imaging characteristics, including nodule size, margin, number, vascular invasion, and growth patterns, allows preoperative prediction of tumor microvascular invasion and patient prognosis. Therefore, the aim of this article is to review the current state-of-the-art and recent advances in the comprehensive noninvasive imaging evaluation of HCC. We also provide the basic key concepts of HCC development and an overview of the current practice guidelines.
Room‐temperature phosphorescence has received much attention owing to its potential applications in information encryption and bioelectronics. However, the preparation of full‐color ...single‐component‐derived phosphorescent materials remains a challenge. Herein, a facile in situ confining strategy is proposed to achieve full‐color phosphorescent carbon dots (CDs) through rapid microwave‐assisted carbonization of citric acid in NaOH. By tuning the mass ratio of citric acid and NaOH, the obtained CDs exhibit tunable phosphorescence wavelengths ranging from 483 to 635 nm and alterable lifetimes from 58 to 389 ms with a synthesis yield of up to 83.7% (>30 g per synthesis). Theoretical calculations and experimental results confirm that the formation of high‐density ionic bonds between cations and CDs leads to efficient afterglow emission via the dissociation of CD arrangement, and the evolution of the aggregation state of CDs results in redshifted phosphorescence. These findings provide a strategy for the synthesis of new insights into achieving and manipulating room‐temperature phosphorescent CDs, and prospect their applications in labeling and information encryption.
By confining isolated carbon dots (CDs) in ionic crystals, a facile in situ confining strategy has been proposed through rapidly microwave‐assisted carbonizing the only source of citric acid in ionic crystals, endowing the CDs with full‐color phosphoresce emission. There is a maximum productivity of 83.7% with a yield of more than 30 g, which can considerably decrease preparation costs.
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