42 research outputs found

    Ethyne Reducing Metal-Organic Frameworks to Control Fabrications of Core/shell Nanoparticles as Catalysts

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    An approach using cobalt metal-organic frameworks (Co-MOF) as precursors is established for the fabrication of cobalt nanoparticles in porous carbon shells (core/shell Co@C). Chemical vapor deposition of ethyne is used for controlling the reduction of cobalt nanoclusters in the MOF and the spontaneous formation of the porous carbon shells. The metallic cobalt cores formed are up to 4 - 6 nm with the crystal phase varying between hexagonally-close-packed (hcp) and face-centre-packed (fcc). The porous carbon shells change from amorphous to graphene with the ethyne deposition temperature increasing from 400 to 600 oC. The core/shell Co@C nanoparticles exhibit high catalytic activity in selectively converting syngas (CTY: 254.1 - 312.1 ΌmolCO·gCo-1·s-1) into hydrocarbons (4.0 - 5.2 gHC·g-cat-1·h-1) at 260 oC. As well as the crystal size and phase, the coordination numbers of the cobalt to oxygen and to other cobalt atoms on the surface of the cobalt nanoparticles, and the permeability of the porous carbon shell have been related to the catalytic performance in FTS reactions

    Size effect of CoS2 cocatalyst on photocatalytic hydrogen evolution performance of g-C3N4

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    The main goal of researchers is to obtain cheap cocatalysts that can promote the photocatalytic activity of catalysts. In this work, a series of CoS2/g-C3N4 (denoted as CoS2/CN) composite photocatalysts were synthesized by photodepositing CoS2 on g-C3N4 surface. The size of CoS2 species could be tuned from single-atom to nanometer scale, which had effect on photocatalysis. The 5CoS2/CN sample with proper nano size of CoS2 cocatalyst had the best photocatalytic performance (1707.19 ÎŒmol g−1h−1) in producing H2 under visible light irradiation (λ > 420 nm). Its photocatalytic activity was about 1434.6 times higher than that of pure g-C3N4 and almost equal with that of Pt/CN catalyst (1799.54 ÎŒmol g−1h−1). The Density Functional Theory (DFT) calculation results further suggested that the ability of accumulating the electrons of the cocatalyst was based on the size effect of CoS2, and the proper size of the cocatalyst efficiently promoted the separation of photogenerated electron-hole pairs.This work was supported by the National Natural Science Foundation of China (21976111) and Shandong Provincial Natural Science Foundation (ZR2019MB052). TEM studies were performed in the Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza (Spain). R.A. acknowledges funding from the Spanish MICIN (PID2019-104739GB-100/AEI/10.13039/501100011033).Peer reviewe

    Comparative Study on the Influence of Different Forms of New Tubular Roof Method Construction on Railway Tracks

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    Through the research on the effect of underpass construction using the New Tubular Roof Method on the overlying strata and railway tracks, the characteristics and pros/cons of three forms of the New Tubular Roof Method are analyzed. Based on the geological conditions and structural dimensions of the Taiyuan Yingze Street Underpass Project, by analogy to the structural sections of Shenyang Metro Xinle Ruins Station and Seoul Metro Lot 923 Station, three research cases were designed: “Taiyuan method”, “Shenyang method” and “Seoul method”. The numerical models are established, and the construction process of three cases are simulated. The results show that the three forms of the New Tubular Roof Method have different characteristics. The impact of construction on the rail is mainly reflected in the absolute settlement, while the offset of the rail and the relative displacement between the rails are small, which are not enough to pose a threat to the driving safety. “Taiyuan method” has the best control effect on the deformation of the rails in general, but there is a complex superimposed interference effect during tube jacking, and the settlement in the tube jacking stage accounts for a large proportion. “Taiyuan method” and “Shenyang method” adopt the integrated inner-connecting tube roof structure to cover the entire excavation area, which have excellent effect of isolating excavation disturbance. However, “Shenyang method” has the problem of excessive settlement during the stage of steel tube incision. The settlement caused by the construction of “Seoul method” in the tube jacking stage is relatively small, and there is no need to perform the complicated and dangerous tube incision. However, the excavation disturbance of “Seoul method” will partially escape from the side of the structure, and the excavation influence range is significantly larger than other methods

    A systematic review and meta-analysis of cross-reactivity of antibodies induced by H7 influenza vaccine

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    Inoculation with vaccine is the major intervention currently used to prevent influenza infections. However, it will be a challenge to produce and implement a new vaccine when a novel highly pathogenic influenza virus emerges in humans as significant infections. H7 subtype influenza viruses have similar epitopes on hemagglutinin, which can induce cross-reactive antibodies. In this study, a meta-analysis of the cross-reactivity of antibodies induced by one H7 subtype influenza vaccine against other H7 subtypes was performed. Database search was conducted in PubMed, Cochrane Library, EMBASE, MEDLINE, Chinese Biological Medicine Database (CBM), and Wanfang. A total of 9 articles comprising 811 human subjects were included in this meta-analysis. All assessed H7 influenza vaccines induced vaccine strain-specific protective antibodies [seroconversion rate (SCR) = 0.74, 95% CI (0.65, 0.82); seroprotection rate (SPR) = 0.81, 95% CI (0.78, 0.83)]. All H7 influenza virus monovalent vaccines exhibited cross-reactivity tested by hemagglutinin inhibition test (HI), microneutralization test (MN) and immunosorbent assay (ELISA) to other H7 subtype viruses. H7N1, H7N3, H7N7, and H7N9 vaccines elicited cross-reactive antibodies against other H7 subtype influenza viruses [SCR = 0.66, 95% CI (0.50, 0.82); SPR = 0.79, 95% CI (0.67, 0.91)]. The pooled SCR (95%CI) of cross-reactivity of H7N1 and H7N3 vaccines were 0.88 (0.85, 0.91) and 0.40 (0.26, 0.54), respectively. The consolidated SPR (95%CI) of H7N1 and H7N7 vaccines were 0.89 (0.86, 0.92) and 0.93 (0.81, 1.06). All H7 vaccines induced cross-reactive antibodies against H7N9 viruses [SCR = 0.69, 95% CI (0.52, 0.86); SPR = 0.85, 95% CI (0.76, 0.94)]. H7 vaccines can be used to limit influenza infection when a new highly pathogenic H7 virus appears

    Immunogenicity of H5N1 influenza vaccines in elderly adults: a systematic review and meta-analysis

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    Several different vaccines have been produced for human use to prevent the highly pathogenic H5N1 influenza. Some studies reported that the clinical effectiveness of influenza vaccines in older adults may be lower than in younger adults. In this study, a meta-analysis of the immunogenicity of H5N1 influenza vaccines in elderly adults was performed. Database search was conducted in EMBASE, PubMed, the Cochrane Library, Chinese VIP, Wanfang and CBM. A total of 3951 elderly adults from 10 articles were included in the meta-analysis. Compared to a single dose, two doses of H5N1 vaccines resulted in the higher seroconversion and seroprotection. For all groups treated with adjuvanted vaccines, there were significant increases (1.55- to 2.16-fold) in the seroconversion rates (SCRs) and seroprotection rates (SPRs) after two immunizations. Oil-in-water emulsion (OE)-adjuvanted 7.5 Όg vaccine caused higher antibody responses than 3.75 Όg of vaccine (SCR: risk ratio (RR) = 1.26 (1.19, 1.33); SPR: RR = 1.25 (1.14, 1.36)). Elderly adults exhibited slightly lower antibody responses only when given 7.5 Όg of OE-adjuvanted vaccine (SCR: RR = 1.06 (1.01, 1.11)) than younger adults. After treatment with the 7.5 Όg of OE-adjuvanted vaccines, the most commonly reported adverse events were injection site pain, swelling and erythema, with the incidence of 32%, 3% and 2%, respectively, and no serious adverse events were found. These data demonstrate that two doses of 7.5 ”g of OE-adjuvanted H5N1 vaccine are well tolerated and induce a robust antibody response in elderly adults

    Strontium-90 brachytherapy following intralesional triamcinolone and 5-fluorouracil injections for keloid treatment: A randomized controlled trial.

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    BackgroundKeloid disease is hard to fully eradicate. Recurrence and other unsatisfactory results were found in many patients. No current therapeutic modality has been determined to be most effective for treating keloid scars. Intralesional corticosteroid injections is most commonly recommended for primary management of small and young keloids as well as hypertrophic scars. However, it's difficult for patients to adhere to long-term triamcinolone acetonide injection therapy because of the pain, inconvenience or complications including hormonal imbalance or irregular menstruation.ObjectiveWe aimed to determine whether and how Strontium-90 brachytherapy as an adjuvant radiation could affect keloid recurrence after intralesional triamcinolone and 5-fluorouracil injections.MethodsWe included keloid patients from March 2019 to September 2019 and randomly allocated them to two groups after 3 intralesional triamcinolone and 5-fluorouracil injections at 3 weeks interval. The experimental group received Strontium-90 brachytherapy at a total dose of 15-20Gy, while the control group didn't receive any adjuvant treatment. We performed both Vancouver Scar Scale scoring and Color Doppler ultrasound examination to monitor and evaluate lesions regularly. A one-year follow-up was completed for each patient.Results31 patients who had 42 keloids in total were recruited. We found intralesional triamcinolone and 5-fluorouracil injections could effectively reduce the thickness and modify the hardness of small and young keloids. Strontium-90 brachytherapy reduced the one-year recurrence rate from 85.7 percent to 44.4 percent after 3 intralesional triamcinolone and 5-fluorouracil injections. The lesions' thickness or elasticity was not affected by Strontium-90 brachytherapy.ConclusionStrontium-90 brachytherapy as an adjuvant radiation could effectively reduce small sized keloids recurrence after intralesional triamcinolone and 5-fluorouracil injections. It worked by enhancing the lesions' stability post-injection.Trial registrationThe clinical trial registration number: ChiCTR2000030141. Name of trial registry: Chinese Clinical Trial Registry (http://www.chictr.org.cn/)

    Effects of 200 Gy 60Co-Îł Radiation on the Regulation of Antioxidant Enzymes, Hsp70 Genes, and Serum Molecules of Plutella xylostella (Linnaeus)

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    The diamondback moth, Plutella xylostella (Linnaeus), is one of the notorious pests causing substantial loses to many cruciferous vegetables across the nations. The effects of 60Co-γ radiation on physiology of P. xylostella were investigated and the results displayed that 200 Gy irradiation significantly alters the antioxidant enzyme regulation in six-day-old male pupae of P. xylostella. First, in our research, we detected Oxidase system and stress response mechanism of irradiated pupae, the results displayed that 200 Gy irradiation significantly alters the antioxidant enzyme regulation in six-day-old male pupae of P. xylostella. The levels of superoxide dismutase (SOD) and catalase (CAT) were increased significantly in contrast the level of peroxidase (POD) and glutathione S-transferase (GST) were decreased in 12–24 h post-treatment. The heat shock proteins (Hsps) gene expression level was significant increasing, maximum > 2-folds upregulation of genes were observed in peak. However, they also had a trend of gradual recovery with development. Second, we detected the testis lactate dehydrogenase (LDH) and acid phosphatase (ACP) activity found that in male adults testis they increased significantly than control during its development. Thus the present research investigation highlights that the 60Co-γ radiation treatments alters the physiological development of diamondback moth. The results showed that 200 Gy dosage resulted in stress damage to the body and reproductive system of the diamondback moth

    Antimicrobial Resistance Profile of mcr-1 Positive Clinical Isolates of Escherichia coli in China From 2013 to 2016

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    Multidrug-resistant (MDR) Escherichia coli poses a great challenge for public health in recent decades. Polymyxins have been reconsidered as a valuable therapeutic option for the treatment of infections caused by MDR E. coll. A plasmid-encoded colistin resistance gene mcr-1 encoding phosphoethanolamine transferase has been recently described in Enterobacteriaceae. In this study, a total of 123 E. coli isolates obtained from patients with diarrheal diseases in China were used for the genetic analysis of colistin resistance in clinical isolates. Antimicrobial resistance profile of polymyxin B (PB) and 11 commonly used antimicrobial agents were determined. Among the 123 E. coli isolates, 9 isolates (7.3%) were resistant to PB and PCR screening showed that seven (5.7%) isolates carried the mcr-1 gene. A hybrid sequencing analysis using singlemolecule, real-time (SMRT) sequencing and Illumina sequencing was then performed to resolve the genomes of the seven mcr-1 positive isolates. These seven isolates harbored multiple plasmids and are MDR, with six isolates carrying one mcr-1 positive plasmid and one isolate (14EC033) carrying two mcr-1 positive plasmids. These eight mcr-1 positive plasmids belonged to the IncX4, Inc12, and IncP1 types. In addition, the mcr-1 gene was the solo antibiotic resistance gene identified in the mcr-1 positive plasmids, while the rest of the antibiotic resistance genes were mostly clustered into one or two plasmids. Interestingly, one mcr-1 positive isolate (14EC047) was susceptible to PB, and we showed that the activity of MCR-1-mediated colistin resistance was not phenotypically expressed in 14EC047 host strain. Furthermore, three isolates exhibited resistance to PB but did not carry previously reported mcr-related genes. Multilocus sequence typing (MAST) showed that these mcr-1 positive E. coil isolates belonged to five different STs, and three isolates belonged to ST301 which carried multiple virulence factors related to diarrhea. Additionally, the mcr-1 positive isolates were all susceptible to imipenem (IMP), suggesting that IMP could be used to treat infection caused by mcr-1 positive E. coli isolates. Collectively, this study showed a high occurrence of mcr1 positive plasmids in patients with diarrheal diseases of Guangzhou in China and the abolishment of the MCR-1 mediated colistin resistance in one E. coli isolate
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