The selective hydrogenation of CO
to value-added chemicals is attractive but still challenged by the high-performance catalyst. In this work, we report that gallium nitride (GaN) catalyzes the direct ...hydrogenation of CO
to dimethyl ether (DME) with a CO-free selectivity of about 80%. The activity of GaN for the hydrogenation of CO
is much higher than that for the hydrogenation of CO although the product distribution is very similar. The steady-state and transient experimental results, spectroscopic studies, and density functional theory calculations rigorously reveal that DME is produced as the primary product via the methyl and formate intermediates, which are formed over different planes of GaN with similar activation energies. This essentially differs from the traditional DME synthesis via the methanol intermediate over a hybrid catalyst. The present work offers a different catalyst capable of the direct hydrogenation of CO
to DME and thus enriches the chemistry for CO
transformations.
Biomimetic assembly of high-quality nanosheets into nacre-like structures can produce macroscopic films with favorable mechanical and optical performances due to the intrinsic properties and high ...level of ordering of the nanoscale building blocks. Natural ground mica is abundant and exhibits great application potential. However, large size and low aspect ratio greatly limit its biomimetic assembly. Moreover, exfoliation of ground mica into high-quality nanosheets remains a significant challenge. Here, we report that large-scale exfoliation of ground mica into mono- or few-layered mica nanosheets with a production rate of ~1.0 g h
can be successfully achieved. The mica nanosheets are then assembled into strong biomimetic polymeric mica film that inherits the high electric insulation, excellent visible transmittance, and unique ultraviolet-shielding properties of natural mica. Its overall performance is superior to that of natural sheet mica and other biomimetic films, making the polymeric mica film a suitable substrate for flexible and transparent devices.
An in situ forming hydrogel has emerged as a promising wound dressing recently. As physically cross-linked hydrogels are normally unstable, most in situ forming hydrogels are chemically cross-linked. ...However, big concerns have remained regarding the slow gelation and the potential toxicity of residual functional groups from cross-linkers or the polymer matrix. Herein, we report a sprayable in situ forming hydrogel composed of poly(N-isopropylacrylamide166-co-n-butyl acrylate9)-poly(ethylene glycol)-poly(N-isopropylacrylamide166-co-n-butyl acrylate9) copolymer (P(NIPAM166-co-nBA9)-PEG-P(NIPAM166-co-nBA9), denoted as PEP) and silver-nanoparticles-decorated reduced graphene oxide nanosheets (Ag@rGO, denoted as AG) in response to skin temperature. This thermoresponsive hydrogel exhibits intriguing sol–gel irreversibility at low temperatures for the stable dressing of a wound, which is attributed to the inorganic/polymeric dual network and abundant coordination interactions between Ag@rGO nanosheets and PNIPAM. The biocompatibility and antibacterial ability against methicillin-resistant Staphylococcus aureus (MRSA) of this PEP-AG hydrogel wound dressing are confirmed in vitro and in vivo, which could transparently promote the healing of a MRSA-infected skin defect.
Lithium (Li) metal batteries (LMBs) face huge challenges to achieve long cycling life at wide temperature range owing to the severe dendrite growth at subambient temperature and the intense side ...reactions with electrolyte at high temperature. Herein, an ultrathin LiBO2 layer with an extremely high Young's modulus of 8.0 GPa is constructed on Li anode via an in situ reaction between Li metal and 4,4,5,5‐tetramethyl‐1,3,2‐dioxa‐borolane (TDB) to form LiBO2@Li anode, which presents two times higher exchange current density than pristine Li anode. The LiBO2 layer presents a strong absorption to Li ions and greatly improves the interfacial dynamics of Li‐ion migration, which induces homogenous lithium nucleation and deposition to form a dense lithium layer. Consequently, the Li dendrite growth during cycling at subambient temperature and the side reactions with electrolyte at high temperature are simultaneously suppressed. The LiBO2@Li/LiNi0.8Co0.1Mn0.1O2 (NCM811) full batteries with limited Li capacity and high cathode mass loading of 9.9 mg cm–2 can steadily cycle for 300 cycles with a capacity retention of 86.6%. The LiBO2@Li/NCM811 full batteries and LiBO2@Li/LiBO2@Li symmetric batteries also present excellent cycling performance at both −20 and 60 °C. This work develops a strategy to achieve outstanding performance of LMBs at wide working temperature‐range.
An ultra‐thin LiBO2 layer with high Young's modulus of 8.0 GPa is constructed on lithium anode via the reaction between lithium metal and 4,4,5,5‐tetramethyl‐1,3,2‐dioxa‐borolane. The LiBO2 layer presents a strong absorption to lithium ions, which greatly accelerates the interfacial dynamics, induces the formation of integrated solid electrolyte interphase and thus allows the steady operation of Li/LiNi0.8Co0.1Mn0.1O2 batteries over a wide temperature range.
Introducing heating function to oil sorbents opens up a new pathway to the fast cleanup of viscous crude oil spills
in situ
. The oil sorption speed increases with the rise of the temperature, thus ...oil sorbents with high heating temperature are desirable. Besides, the oil sorbents also need to be produced environment-friendly. Here we present carbonized melamine-formaldehyde sponges (CMSs) that exhibited superior heating performance and the CMSs could be massively fabricated through a non-polluting pyrolysis process. The conductive CMSs could be heated over 300 °C with a low applied voltage of 6.9 V and keep above 250 °C for 30 min in the air without obvious damage. Such high heating performance enabled heating up the oil spills with a high rate of 2.65 °C·s
−1
and 14% improvement of oil sorption coefficient compared with the state-of-the-art value. We demonstrated that one joule-heated CMS could continuously and selectively collect viscous oil spills (9,010 mPa·s) 690 times its own weight in one hour. The CMSs will be a highly competitive sorbent material for the fast remediation of future crude oil spills.
Recent studies have demonstrated that commercially available lipid‐lowering drugs cause various side effects; therefore, searching for anti‐hyperlipidaemic compounds with lower toxicity is a research ...hotspot. This study was designed to investigate whether the marine‐derived compound, 5‐hydroxy‐3‐methoxy‐5‐methyl‐4‐butylfuran‐2(5H)‐one, has an anti‐hyperlipidaemic activity, and the potential underlying mechanism in vitro. Results showed that the furanone had weaker cytotoxicity compared to positive control drugs. In RAW 264.7 cells, the furanone significantly lowered ox‐LDL‐induced lipid accumulation (~50%), and its triglyceride (TG)‐lowering effect was greater than that of liver X receptor (LXR) agonist T0901317. In addition, it significantly elevated the protein levels of peroxisome proliferator‐activated receptors (PPARα) and ATP‐binding cassette (ABC) transporters, which could be partially inhibited by LXR antagonists, GSK2033 and SR9243. In HepG2 cells, it significantly decreased oleic acid‐induced lipid accumulation, enhanced the protein levels of low‐density lipoprotein receptor (LDLR), ABCG5, ABCG8 and PPARα, and reduced the expression of sterol regulatory element‐binding protein 2 (~32%). PPARα antagonists, GW6471 and MK886, could significantly inhibit the furanone‐induced lipid‐lowering effect. Furthermore, the furanone showed a significantly lower activity on the activation of the expression of lipogenic genes compared to T0901317. Taken together, the furanone exhibited a weak cytotoxicity but had powerful TC‐ and TG‐lowering effects most likely through targeting LXRα and PPARα, respectively. These findings indicate that the furanone has a potential application for the treatment of dyslipidaemia.
Growing concerns surround the mid Guangdong coasts, one of China’s fastest and developing economical regions. To study the environmental impacts of economic and industrial development, we measured ...ten metallic elements (Hg, Pb, Cu, Zn, Fe, Al, Ni, Sr, Li, and Co) in surface sediments from nineteen stations in three bays. All these metals showed concentrations substantially higher than their background values, suggesting possible anthropogenic pollution. Highest metal levels were close to the nuclear power plants likely as a result of nuclear waste discharges. Results revealed that Hg, Pb, and Sr largely originated from human activities, while Cu, Ni, Co, Al, and Fe mainly from natural rock weathering. Two types of anthropogenic sources were identified through a principal component analysis, one from shipping industry, port transport service and nuclear power plants, and the other from municipal sewage and coal power plant.
► Ten metallic elements in surface sediments from mid Guangdong coasts were measured. ► High metal levels occurred close to the nuclear power plants. ► Hg, Pb and Sr mainly originated from human activities. ► Two types of anthropogenic metallic sources were identified in this region.
Hot spots of metallic elements were close to the nuclear power plants. Industrial and municipal discharges were the main anthropogenic metallic source.
To investigate the serotypes, antibiotic susceptibilities, and multi-locus sequence type (MLST) profiles of Streptococcus agalactiae (S. agalactiae) in Beijing to provide references for the ...prevention and treatment of S. agalactiae infections.
All isolates were identified using the CAMP test and the latex-agglutination assay and serotyped using a Strep-B-Latex kit, after which they were assessed for antibiotic susceptibility, macrolide-resistance genes, and MLST profiles.
In total, 56 S. agalactiae isolates were identified in 863 pregnant women (6.5%). Serotypes Ia, Ib, II, III, and V were identified, among which types III (32.1%), Ia (17.9%), Ib (16.1%), and V (14.3%) were the predominant serotypes. All isolates were susceptible to penicillin and ceftriaxone. The nonsusceptiblity rates measured for erythromycin, clarithromycin, azithromycin, telithromycin, clindamycin, tetracycline, and levofloxacin were 85.7%, 92.9%, 98.2%, 30.4%, 73.2%, 91%, and 39.3%, respectively. We identified 14 sequence types (STs) for the 56 isolates, among which ST19 (30.4%) was predominant. The rate of fluoroquinolone resistance was higher in serotype III than in the other serotypes. Among the 44 erythromycin-resistant isolates, 32 (72.7%) carried ermB.
S. agalactiae isolates of the serotypes Ia, Ib, III, and V are common in Beijing. Among the S. agalactiae isolates, the macrolide and clindamycin resistance rates are extremely high. Most of the erythromycin-resistant isolates carry ermB.
The paradigm of the Internet of Things (IoT) and edge computing brings a number of heterogeneous devices to the network edge for monitoring and controlling the environment. For reacting to events ...dynamically and automatically in the environment, rule-enabled IoT edge platforms operate the deployed service scenarios at the network edge, based on filtering events to perform control actions. However, due to the heterogeneity of the IoT edge networks, deploying a consistent rule context for operating a consistent rule scenario on multiple heterogeneous IoT edge platforms is difficult because of the difference in protocols and data formats. In this paper, we propose a transparent rule enablement, based on the commonization approach, for enabling a consistent rule scenario in heterogeneous IoT edge networks. The proposed IoT Edge Rule Agent Platform (IERAP) deploys device proxies to share consistent rules with IoT edge platforms without considering the difference in protocols and data formats. Therefore, each device proxy only considers the translation of the corresponding platform-specific and common formats. Also, the rules are deployed by the corresponding device proxy, which enables rules to be deployed to heterogeneous IoT edge platforms to perform the consistent rule scenario without considering the format and underlying protocols of the destination platform.
To analyse clinical characteristics, antibiotic susceptibility, and risk factors for mortality in paediatric invasive pneumococcal disease (IPD) in Beijing.
Paediatric IPD patients in our hospital ...were retrospectively collected from 2012 to 2017. Clinical manifestations, laboratory tests, antimicrobial susceptibility and serotype of isolates, and risk factors for mortality of IPD were analysed.
Overall, 186 IPD cases were enrolled. The major manifestations were meningitis (76), pneumonia with bacteraemia (60), bacteraemia without focus (21), and pneumonia with empyaema (22). Of 72 cases with underlying diseases, leukaemia (18.0%), congenital heart disease (15.3%), primary immunodeficiency disease (12.5%), nephrotic syndrome (12.5%), and cerebrospinal fluid leakage (12.5%) were most common. In total 96.9% of isolates would have been covered by the pneumococcal conjugate vaccine (PCV13), including 19F (32.8%), 19A (23.4%), 4 (17.2%), and 23F (9.4%). Nonsusceptibility rates of penicillin, cefotaxime, and cefepime among nonmeningitis patients increased between 2012 and 2017; The mortality rate was 21.5%. Meningitis, respiratory failure, multiple organ failure, and white blood cell count < 4000 cells/μL were independent risk factors for mortality.
Meningitis was the most common clinical manifestation of IPD, and was frequently associated with death. Strains in the PCV13 vaccine would cover most of the cases, and so wider use of PCV13 should be considered.
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