The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly effici...The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.展开更多
Microorganisms actively participate in biogeochemical cycling processes and play a crucial role in maintaining the dynamic balance of hot spring ecosystems.However,the distribution of microbial functional genes and th...Microorganisms actively participate in biogeochemical cycling processes and play a crucial role in maintaining the dynamic balance of hot spring ecosystems.However,the distribution of microbial functional genes and their influencing factors in hot springs remain largely unclear.Therefore,this study investigated the microbial functional genes and their potential for controlling biogeochemical cycles(C,N,S,and P) in the hot Springs of Tengchong,China,using the Geochip method,a functional gene microarray technology.The examined hot springs have very different microbial functional genes.A total of 22 736 gene probe signals were identified,belonging to 567 functional genes and associated with 15 ecological functions,mainly involving stress response,carbon cycle,nitrogen cycle,sulfur cycle,phosphorus cycle and energy processes.The amyA,narG,dsrA and ppx genes were most abundant in carbon,nitrogen,sulfur and phosphorus cycles,respectively,and were significantly correlated with pH,temperature and SO_(4)^(2-).The diversity and abundance of detected gene probes were negatively correlated with temperature.The α-diversity(i.e.,Shannon index) was high at low temperature and low pH.Molecular functional interactions revealed by the gene connectivity levels were negatively correlated with temperature,pH and SO_(4)^(2-).These results suggested that the abundance,diversity and interactions of microbial functional genes were significantly influenced by geochemical parameters.-In addition,some genera possessed functional genes related to carbon,nitrogen,sulfur,and phosphorus cycles and can synergistically control the biogeochemical cycles of carbon,nitrogen,sulfur and phosphorus.These findings provide new insights into the functional potentials of microorganisms to participate in biogeochemical cycles and their responses to environmental factors in hot springs.展开更多
BACKGROUND： Bone marrow stromal cells （BMSCs） or Schwann cells （SCs） transplantation alone can treat spinal cord injury. However, the transplantation either cell-type alone has disadvantages. The co-transplantati...BACKGROUND： Bone marrow stromal cells （BMSCs） or Schwann cells （SCs） transplantation alone can treat spinal cord injury. However, the transplantation either cell-type alone has disadvantages. The co-transplantation of both cells may benefit structural reconstruction and functional recovery of spinal nerves. OBJECTIVE： To verify spinal cord repair and related mechanisms after co-transplantation of BMSCs and SCs in a rat model of hemisected spinal cord injury. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Department of Histology and Embryology, Mudanjiang Medical College from January 2008 to May 2009. MATERIALS： Rabbit anti-S-100, glial fibrillary acidic protein, neuron specific enolase and neurofilament-200 monoclonal antibodies were purchased from Sigma, USA. METHODS： A total of 100 Wistar rats were used in a model of hemisected spinal cord injury. The rats were randomly assigned to vehicle control, SCs transplantation, BMSCs transplantation, and co-transplantation groups; 25 rats per group. At 1 week after modeling, SCs or BMSCs cultured in vitro were labeled and injected separately into the hemisected spinal segment of SCs and BMSCs transplantation groups through three injection points [5 μL （1 x 107 cells/mL）] cell suspension in each point）. In addition, a 15 μL 1 × 10^7 cells/mL SCs suspension and a 15 μL 1 × 10^7 cells/mL BMSC suspension were injected into co-transplantation group by the above method. MAIN OUTCOME MEASURES： The Basso-Beattie-Bresnahan （BBB） locomotor rating scale and somatosensory evoked potential （SEP） tests were used to assess the functional recovery of rat hind limbs following operation. Structural repair of injured nerve tissue was observed by light microscopy, electron microscopy, immunohistochemistry, and magnetic resonance imaging （MRI）. In vivo differentiation, survival and migration of BMSCs were evaluated by immunofluorescence. RESULTS： BBB scores were significantly greater in all three transplantation groups compared with vehicle control group 8 weeks after transplantation. In particular, the co-transplantation group displayed the highest scores among the groups （P 〈 0.05）. Moreover, recovery of SEP latency and amplitude was observed in all the transplantation groups, particularly after 8 weeks. Again, the co-transplantation group exhibited the greatest improvement （P 〈 0.05）. In the co-transplantation group, imaging showed a smooth surface and intact inner structure at the injury site, with no scar formation, and a large number of orderly cells at the injured site. Axonal regeneration, new myelination, and a large amount of cell division were detected in the co-transplantation group by electron microscopy. Neuron specific enolase （NSE）- and glial fibriilary acidic protein （GFAP）-positive cells were observed in the spinal cord sections 1 week following co-transplantation by immunofluorescence staining. CONCLUSION： Co-transplantation of SCs and BMSCs effectively promoted functional recovery of injured spinal cord in rats compared with SCs or BMSCs transplantation alone. This repair effect is probably achieved because of neuronal-like cells derived from BMSCs to supplement dead neurons in vivo.展开更多
The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clos...The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.展开更多
The activity and stability of Cu nanostructures strongly depend on their sizes,morphology and structures.Here we report the preparation of two-dimensional(2 D)Cu@Cu-BTC core-shell nanosheets(NSs).The thickness of the ...The activity and stability of Cu nanostructures strongly depend on their sizes,morphology and structures.Here we report the preparation of two-dimensional(2 D)Cu@Cu-BTC core-shell nanosheets(NSs).The thickness of the Cu NSs could be tuned to sub-10 nm through a mild etching process,in which the Cu-BTC in situ grow along with the oxidation on the surface of the Cu NSs.This unique strategy can also be extended to synthesize one-dimensional(1 D)Cu@Cu-BTC nanowires(NWs).Furthermore,the obtained Cu@Cu-BTC NSs could be applied as an effective material to the memory device with the write-onceread-many times(WORM)behavior and the high ION/I(OFF)ratio(>2.7×103).展开更多
An ensemble-based method for the observation system simulation experiment(OSSE)is employed to design optimal observation stations and assess the present observation stations in the northeastern South China Sea(SCS).We...An ensemble-based method for the observation system simulation experiment(OSSE)is employed to design optimal observation stations and assess the present observation stations in the northeastern South China Sea(SCS).We employed the 20-year(1992-2012)sea surface height(SSH)data to design an array to monitor the intraseasonal to interannual variability.The results show that the most key region was found located at the northwest of Luzon Island(LI)where the energetic Luzon cyclonic gyre(LCG)occurs;other key regions include the edge of the LCG,the northwest of the Luzon Strait(LS),and the southwest of Taiwan,China.By contrast,we found that the present observation stations might oversample at the northwest of the LS and undersample at the northwest of LI.In addition,the optimal stations perform better in a larger area than the present stations.In vertical direction,the key layer is located within the upper 200-m depth,of which the surface and subsurface layers are most valuable to the observing system.展开更多
There are two main opposing views in the wireless industry on the feasibility of developing 5th generation(5G) cellular networks in mm-Wave bands. The optimistic view is based on the fact that the path loss in mm Wave...There are two main opposing views in the wireless industry on the feasibility of developing 5th generation(5G) cellular networks in mm-Wave bands. The optimistic view is based on the fact that the path loss in mm Wave bands is not significantly worse than that in cellular bands when beamforming gain is also considered. The cautious view points out the significant blockage issues due to the lack of diffraction and adequate penetration in mm Wave bands. The implementation of 5G mm Wave cellular networks also faces major challenges due to the high link budget needed for long- range communication and the strong dependency on beamforming technology. This paper addresses some of these fundamental technology issues, from mm Wave channel characters and channel modeling to the implications on system and network architecture design.Although we believe that mm Wave can be used for 5G networks, we show that the air interface, device and network design will be very different from existing cellular design.展开更多
Coordinatively unsaturated metal sites(CUS)located at tetrahedral(T_(d))in spinel structure are highly effective for activating peroxymonosulfate(PMS)in Fenton-like catalysis.However,the conventional T_(d)-octahedral(...Coordinatively unsaturated metal sites(CUS)located at tetrahedral(T_(d))in spinel structure are highly effective for activating peroxymonosulfate(PMS)in Fenton-like catalysis.However,the conventional T_(d)-octahedral(Oh)connectivity in spinel structures restricts internal electron transfer,limiting the regeneration of low-valent metals and creating a trade-off between catalytic activity and long-term stability.Herein,we address this challenge by engineering a novel T_(d)-T_(d) connectivity in amorphous CoFeO_(x) nanosheets(a-CoFeO_(x) NSs).Soft X-ray absorption spectroscopy(sXAS)measurements reveal that in a-CoFeO_(x) nanosheets,the ligand field symmetry around Co atoms is dominated by a T_(d) coordination,in contrast to the O_(h) coordination in the crystalline state,which introduces T_(d)-T_(d) connection.Density functional theory(DFT)calculations confirm that the T_(d)-T_(d) connection in a-CoFeO_(x) structure significantly strengthens electron transfer to activate PMS,which exhibited a first-order kinetic constant(k_(obs))of 0.27 min^(-1) for sulfamethoxazole(SMX)removal with high stability.This study reveals that the phase-engineered CUS can further enhance catalytic activity and provides a simple and scalable strategy for optimizing spinel-type catalysts.展开更多
Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispe...Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH＋4 Faradaic efficiency of 11.1 % achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH＋4 yield rate of 1,305 μg h-1 mg-1Au has been reached, which is roughly 22.5 times as high as that by sup- ported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH＋4 can be electro- chemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ-1. Our study provides a possibility of replacing the Haber-Bosch process with environmentally benign and energy-efficient electrochemical strategies.展开更多
Nitrite-dependent anaerobic methane-oxidiz- ing （n-damo） bacteria and anaerobic ammonia oxidizing （anammox） bacteria are two groups of microorganisms involved in global carbon and nitrogen cycling. In order to tes...Nitrite-dependent anaerobic methane-oxidiz- ing （n-damo） bacteria and anaerobic ammonia oxidizing （anammox） bacteria are two groups of microorganisms involved in global carbon and nitrogen cycling. In order to test whether the n-damo and anammox bacteria co-occur in natural saline environments, the DNA and cDNA samples obtained from the surficial sediments of two saline lakes （with salinity of 32 and 84 g/L, respectively） on the Tibetan Plateau were PCR-amplified with the use of anammox- and n-damo-specific primer sets, followed by clone library construction and phylogenetic analysis. DNA and cDNA- based clones affiliated with n-damo and anammox bacteria were successfully retrieved from the two samples, indicating that these two groups of bacteria can co-occur in natural saline environments with salinity as high as 84g/L. Our finding has great implications for our understanding of the global carbon and nitrogen cycle in nature.展开更多
With the recent ongoing autumn/winter 2022 COVID-19 wave and the adjustment of public health control measures,there have been widespread SARS-CoV-2 infections in Chinese mainland.Here we have analyzed 369 viral genome...With the recent ongoing autumn/winter 2022 COVID-19 wave and the adjustment of public health control measures,there have been widespread SARS-CoV-2 infections in Chinese mainland.Here we have analyzed 369 viral genomes from recently diagnosed COVID-19 patients in Shanghai,identifying a large number of sublineages of the SARS-CoV-2 Omicron family.Phylogenetic analysis,coupled with contact history tracing,revealed simultaneous community transmission of two Omicron sublineages dominating the infections in some areas of China(BA.5.2 mainly in Guangzhou and Shanghai,and BF.7 mainly in Beijing)and two highly infectious sublineages recently imported from abroad(XBB and BQ.1).Publicly available data from August 31 to November 29,2022 indicated an overall severe/critical case rate of 0.035%nationwide,while analysis of 5706 symptomatic patients treated at the Shanghai Public Health Center between September 1 and December 26,2022 showed that 20 cases(0.35%)without comorbidities progressed into severe/critical conditions and 153 cases(2.68%)with COVID-19-exacerbated comorbidities progressed into severe/critical conditions.These observations shall alert healthcare providers to place more resources for the treatment of severe/critical cases.Furthermore,mathematical modeling predicts this autumn/winter wave might pass through major cities in China by the end of the year,whereas some middle and western provinces and rural areas would be hit by the upcoming infection wave in mid-to-late January 2023,and the duration and magnitude of upcoming outbreak could be dramatically enhanced by the extensive travels during the Spring Festival(January 21,2023).Altogether,these preliminary data highlight the needs to allocate resources to early diagnosis and effective treatment of severe cases and the protection of vulnerable population,especially in the rural areas,to ensure the country’s smooth exit from the ongoing pandemic and accelerate socio-economic recovery.展开更多
The electrochemical CO_(2) reduction reaction(CO_(2)RR)holds significant promise in advancing carbon neutrality.Developing catalysts for the electrochemical CO_(2)RR to multi-carbon(C_(2+))products(e.g.,C_(2)H_(4))und...The electrochemical CO_(2) reduction reaction(CO_(2)RR)holds significant promise in advancing carbon neutrality.Developing catalysts for the electrochemical CO_(2)RR to multi-carbon(C_(2+))products(e.g.,C_(2)H_(4))under industrial-level current density is urgently needed and pivotal.Herein,we report the Cu_(2)O nanoparticles doped with interstitial carbon atoms(denoted as C-Cu_(2)O NPs)for the conversion of CO_(2) to C_(2+)products.The interstitial carbon promotes the C-Cu_(2)O NPs to possess abundant unsaturated Cu–O bonds,leading to a high-density Cu^(δ+)(0<δ<1)species.The obtained C-Cu_(2)O NPs exhibited significant Faradic efficiency(FE)of C_(2+) products approaching 76.9%and a partial current density reaching 615.2 mA·cm^(–2)under an industrial-level current density of 800 mA·cm^(–2).Furthermore,the efficient electrosynthesis of C_(2)H_(4) achieved an FE of 57.4%with a partial current density of 459.2 mA·cm^(–2).In situ electrochemical attenuated total reflection Fourier transform infrared spectroscopy and in situ Raman spectroscopy analyses revealed that C-Cu_(2)O NPs stabilized the intermediate*CO and facilitated C–C coupling,leading to increased selectivity towards C_(2+) products.展开更多
Manipulating the oxidation state of Cu catalysts can significantly affect the selectivity and activity of electrocatalytic carbon dioxide reduction(CO_(2)RR).However,the thermodynamically favorable cathodic reduction ...Manipulating the oxidation state of Cu catalysts can significantly affect the selectivity and activity of electrocatalytic carbon dioxide reduction(CO_(2)RR).However,the thermodynamically favorable cathodic reduction to metallic states typically leads to catalytic deactivation.Herein,a defect construction strategy is employed to prepare crystalline/amorphous Cu_(2+1)O/CuO_(x)heterostructures(c/a-CuO_(x))with abundant Cu0 and Cuδ+(0<δ<1)sites for CO_(2)RR.The C^(2+)Faradaic efficiency of the heterostructured Cu catalyst is up to 81.3%,with partial current densities of 406.7 mA·cm−2.Significantly,real-time monitoring of the Cu oxidation state evolution by in-situ Raman spectroscopy confirms the stability of Cuδ+species under long-term high current density operation.Density functional theory(DFT)calculations further reveal that the adjacent Cu0 and Cuδ+sites in heterostructured c/a-CuO_(x)can efficiently reduce the energy barrier of CO coupling for C^(2+)products.展开更多
The rational fabrication of highly efficient electrocatalysts with low cost toward oxygen evolution reaction(OER)is greatly desired but remains a formidable challenge.In this work,we present a facile and straightforwa...The rational fabrication of highly efficient electrocatalysts with low cost toward oxygen evolution reaction(OER)is greatly desired but remains a formidable challenge.In this work,we present a facile and straightforward method of incorporating NiCo-layered double hydroxide(NiCo-LDH)into GO-dispersed CNTs(GO-CNTs)with interconnected configuration.X-ray absorption spectroscopy(XAS)reveals the strong electron interaction between NiCo-LDH and the underlying GO-CNTs substrate,which is supposed to facilitate charge transfer and accelerate the kinetics for OER.By tuning the amount of CNTs,the optimized NiCo-LDH/GO-CNTs composite can achieve a low overpotential of 290 mV at 10 mA·cm^(−2) current density,a small Tafel slope of 66.8 mV·dec^(−1) and robust stability,superior to the pure NiCo-LDH and commercial RuO_(2) in alkaline media.The preeminent oxygen evolution performance is attributed to the synergistic effect stemming from the merits and the intimate electron interaction between LDH and GO-CNTs.This allows NiCo-LDH/GO-CNTs to be potentially applied in an industrial non-noble metal-based water electrolyzer as the anodic catalysts.展开更多
To unveil the nature of amorphous states,single-element amorphous metals have been the perfect research subject due to the simplest composition.However,the extreme crystal nucleation and growth rate in single-element ...To unveil the nature of amorphous states,single-element amorphous metals have been the perfect research subject due to the simplest composition.However,the extreme crystal nucleation and growth rate in single-element metal make the synthesis of single-element amorphous metals seemingly impossible in the past.Fortunately,benefited by several delicate synthetic strategies developed recently,the single-element amorphous metals have been successfully demonstrated.This review aims to provide a systematic overview of the synthesis of single-element amorphous metals covering the challenges in physics and recent achieve-ments.In addition,current understanding of the atomic and electronic structures of single-element amorphous metal has also been included.Finally,the challenges that worth further investigation are discussed.By identifying the potential avenues for further exploration,this review aims to contribute valuable insights that will propel the cognition of single-element amorphous metals.展开更多
基金supported by the National Key R&D Program of China(2018YFA0702001)National Natural Science Foundation of China(22371268,22301287)+3 种基金Fundamental Research Funds for the Central Universities(WK2060000016)Anhui Provincial Natural Science Foundation(2208085J09,2208085QB33)Collaborative Innovation Program of Hefei Science Center,CAS(2022HSC-CIP020)Youth Innovation Promotion Association of the Chinese Academy of Science(2018494)and USTC Tang Scholar.
文摘The hydrazine oxidation reaction(HzOR)has garnered significant attention as a feasible approach to replace sluggish anodic reactions to save energy.Nevertheless,there are still difficulties in developing highly efficient catalysts for the HzOR.Herein,we report amorphous ruthenium nanosheets(a-Ru NSs)with a thickness of approximately 9.6 nm.As a superior bifunctional electrocatalyst,a-Ru NSs exhibited enhanced electrocatalytic performance toward both the HzOR and hydrogen evolution reaction(HER),outperforming benchmark Pt/C catalysts,where the a-Ru NSs achieved a work-ing potential of merely-76 mV and a low overpotential of only 17 mV to attain a current density of 10 mA·cm^(-2) for the HzOR and HER,respectively.Furthermore,a-Ru NSs displayed a low cell voltage of 28 mV at 10 mA·cm^(-2) for overall hy-drazine splitting in a two-electrode electrolyzer.In situ Raman spectra revealed that the a-Ru NSs can efficiently promote N‒N bond cleavage,thereby producing more*NH_(2)and accelerating the progress of the reaction.
基金supported by grants from the National Natural Science Foundation of China(Nos.42172339,91951205)。
文摘Microorganisms actively participate in biogeochemical cycling processes and play a crucial role in maintaining the dynamic balance of hot spring ecosystems.However,the distribution of microbial functional genes and their influencing factors in hot springs remain largely unclear.Therefore,this study investigated the microbial functional genes and their potential for controlling biogeochemical cycles(C,N,S,and P) in the hot Springs of Tengchong,China,using the Geochip method,a functional gene microarray technology.The examined hot springs have very different microbial functional genes.A total of 22 736 gene probe signals were identified,belonging to 567 functional genes and associated with 15 ecological functions,mainly involving stress response,carbon cycle,nitrogen cycle,sulfur cycle,phosphorus cycle and energy processes.The amyA,narG,dsrA and ppx genes were most abundant in carbon,nitrogen,sulfur and phosphorus cycles,respectively,and were significantly correlated with pH,temperature and SO_(4)^(2-).The diversity and abundance of detected gene probes were negatively correlated with temperature.The α-diversity(i.e.,Shannon index) was high at low temperature and low pH.Molecular functional interactions revealed by the gene connectivity levels were negatively correlated with temperature,pH and SO_(4)^(2-).These results suggested that the abundance,diversity and interactions of microbial functional genes were significantly influenced by geochemical parameters.-In addition,some genera possessed functional genes related to carbon,nitrogen,sulfur,and phosphorus cycles and can synergistically control the biogeochemical cycles of carbon,nitrogen,sulfur and phosphorus.These findings provide new insights into the functional potentials of microorganisms to participate in biogeochemical cycles and their responses to environmental factors in hot springs.
基金the National Natural Science Foundation of China, No. C010602the Natural Science Foundation of Heilongjiang Province, No. D200559the Scientific Research Program of Educa-tion Department of Heilong-jiang Province, No. 11511428
文摘BACKGROUND： Bone marrow stromal cells （BMSCs） or Schwann cells （SCs） transplantation alone can treat spinal cord injury. However, the transplantation either cell-type alone has disadvantages. The co-transplantation of both cells may benefit structural reconstruction and functional recovery of spinal nerves. OBJECTIVE： To verify spinal cord repair and related mechanisms after co-transplantation of BMSCs and SCs in a rat model of hemisected spinal cord injury. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Department of Histology and Embryology, Mudanjiang Medical College from January 2008 to May 2009. MATERIALS： Rabbit anti-S-100, glial fibrillary acidic protein, neuron specific enolase and neurofilament-200 monoclonal antibodies were purchased from Sigma, USA. METHODS： A total of 100 Wistar rats were used in a model of hemisected spinal cord injury. The rats were randomly assigned to vehicle control, SCs transplantation, BMSCs transplantation, and co-transplantation groups; 25 rats per group. At 1 week after modeling, SCs or BMSCs cultured in vitro were labeled and injected separately into the hemisected spinal segment of SCs and BMSCs transplantation groups through three injection points [5 μL （1 x 107 cells/mL）] cell suspension in each point）. In addition, a 15 μL 1 × 10^7 cells/mL SCs suspension and a 15 μL 1 × 10^7 cells/mL BMSC suspension were injected into co-transplantation group by the above method. MAIN OUTCOME MEASURES： The Basso-Beattie-Bresnahan （BBB） locomotor rating scale and somatosensory evoked potential （SEP） tests were used to assess the functional recovery of rat hind limbs following operation. Structural repair of injured nerve tissue was observed by light microscopy, electron microscopy, immunohistochemistry, and magnetic resonance imaging （MRI）. In vivo differentiation, survival and migration of BMSCs were evaluated by immunofluorescence. RESULTS： BBB scores were significantly greater in all three transplantation groups compared with vehicle control group 8 weeks after transplantation. In particular, the co-transplantation group displayed the highest scores among the groups （P 〈 0.05）. Moreover, recovery of SEP latency and amplitude was observed in all the transplantation groups, particularly after 8 weeks. Again, the co-transplantation group exhibited the greatest improvement （P 〈 0.05）. In the co-transplantation group, imaging showed a smooth surface and intact inner structure at the injury site, with no scar formation, and a large number of orderly cells at the injured site. Axonal regeneration, new myelination, and a large amount of cell division were detected in the co-transplantation group by electron microscopy. Neuron specific enolase （NSE）- and glial fibriilary acidic protein （GFAP）-positive cells were observed in the spinal cord sections 1 week following co-transplantation by immunofluorescence staining. CONCLUSION： Co-transplantation of SCs and BMSCs effectively promoted functional recovery of injured spinal cord in rats compared with SCs or BMSCs transplantation alone. This repair effect is probably achieved because of neuronal-like cells derived from BMSCs to supplement dead neurons in vivo.
基金support from the National Key Research and Development Program of China (No.2020YFA0907300)the National Natural Science Foundation of China (No.22077069)+1 种基金the Natural Science Foundation of Tianjin (19JCZDJC33400)the Fundamental Research Funds for the Central Universities,Nankai University (63201111).
文摘The conversion of CO_(2) into fuels and valuable chemicals is one of the central topics to combat climate change and meet the growing demand for renewable energy.Herein,we show that the formate dehydrogenase from Clostridium ljungdahlii(ClFDH)adsorbed on electrodes displays clear characteristic voltammetric signals that can be assigned to the reduction and oxidation potential of the[4Fe-4S]^(2+/+)cluster under nonturnover conditions.Upon adding substrates,the signals transform into a specific redox center that engages in catalytic electron transport.ClFDH catalyzes rapid and efficient reversible interconversion between CO_(2) and formate in the presence of substrates.The turnover frequency of electrochemical CO_(2) reduction is determined as 1210 s^(-1) at 25℃ and pH 7.0,which can be further enhanced up to 1786 s^(-1) at 50℃.The Faradaic efficiency at−0.6 V(vs.standard hydrogen electrode)is recorded as 99.3%in a 2-h reaction.Inhibition experiments and theoretical modeling disclose interesting pathways for CO_(2) entry,formate exit,and OCN−competition,suggesting an oxidation-state-dependent binding mechanism of catalysis.Our results provide a different perspective for understanding the catalytic mechanism of FDH and original insights into the design of synthetic catalysts.
基金supported by the National Key R&D Program of China(No.2017YFA0700104)National Natural Science Foundation of China(Nos.21571169,21871238)+2 种基金Fundamental Research Funds for the Central Universities(No.WK2060190081)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2018494)Young Elite Scientists Sponsorship Program by CAST(No.2016QNRC001)
文摘The activity and stability of Cu nanostructures strongly depend on their sizes,morphology and structures.Here we report the preparation of two-dimensional(2 D)Cu@Cu-BTC core-shell nanosheets(NSs).The thickness of the Cu NSs could be tuned to sub-10 nm through a mild etching process,in which the Cu-BTC in situ grow along with the oxidation on the surface of the Cu NSs.This unique strategy can also be extended to synthesize one-dimensional(1 D)Cu@Cu-BTC nanowires(NWs).Furthermore,the obtained Cu@Cu-BTC NSs could be applied as an effective material to the memory device with the write-onceread-many times(WORM)behavior and the high ION/I(OFF)ratio(>2.7×103).
基金Supported by the National Key Research&Development Plan of China(Nos.2016YFC1401703,2016YFC1401702,2018YFC0309803)the National Natural Science Foundation of China(Nos.41506002,41676010,41476011,41676015,41606026)+1 种基金the Institution of South China Sea Ecology and Environmental Engineering,Chinese Academy of Sciences(No.ISEE2019ZR0)the Guangzhou Science and Technology Foundation(No.201804010133)。
文摘An ensemble-based method for the observation system simulation experiment(OSSE)is employed to design optimal observation stations and assess the present observation stations in the northeastern South China Sea(SCS).We employed the 20-year(1992-2012)sea surface height(SSH)data to design an array to monitor the intraseasonal to interannual variability.The results show that the most key region was found located at the northwest of Luzon Island(LI)where the energetic Luzon cyclonic gyre(LCG)occurs;other key regions include the edge of the LCG,the northwest of the Luzon Strait(LS),and the southwest of Taiwan,China.By contrast,we found that the present observation stations might oversample at the northwest of the LS and undersample at the northwest of LI.In addition,the optimal stations perform better in a larger area than the present stations.In vertical direction,the key layer is located within the upper 200-m depth,of which the surface and subsurface layers are most valuable to the observing system.
文摘There are two main opposing views in the wireless industry on the feasibility of developing 5th generation(5G) cellular networks in mm-Wave bands. The optimistic view is based on the fact that the path loss in mm Wave bands is not significantly worse than that in cellular bands when beamforming gain is also considered. The cautious view points out the significant blockage issues due to the lack of diffraction and adequate penetration in mm Wave bands. The implementation of 5G mm Wave cellular networks also faces major challenges due to the high link budget needed for long- range communication and the strong dependency on beamforming technology. This paper addresses some of these fundamental technology issues, from mm Wave channel characters and channel modeling to the implications on system and network architecture design.Although we believe that mm Wave can be used for 5G networks, we show that the air interface, device and network design will be very different from existing cellular design.
基金supported by the National Natural Science Foundation of China(Nos.22371268,52025101,U23A20676,and 52400103)Fundamental Research Funds for the Central Universities(No.WK2060000016 and WK2060000069)+6 种基金Anhui Province for Outstanding Youth(No.2208085J09)Collaborative Innovation Program of Hefei Science Center,CAS(No.2022HSC-CIP020)Anhui Development and Reform Commission(No.AHZDCYCX-2SDT2023-07)Youth Innovation Promotion Association of the Chinese Academy of Science(No.2018494)USTC Tang Scholar,Suzhou Carbon Peaking and Carbon Neutrality Science and Technology Support Key Special Funding(No.ST202217)the China Postdoctoral Science Foundation(Nos.2023M743380 and 2024T170886)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation project(No.GZC20232544).
文摘Coordinatively unsaturated metal sites(CUS)located at tetrahedral(T_(d))in spinel structure are highly effective for activating peroxymonosulfate(PMS)in Fenton-like catalysis.However,the conventional T_(d)-octahedral(Oh)connectivity in spinel structures restricts internal electron transfer,limiting the regeneration of low-valent metals and creating a trade-off between catalytic activity and long-term stability.Herein,we address this challenge by engineering a novel T_(d)-T_(d) connectivity in amorphous CoFeO_(x) nanosheets(a-CoFeO_(x) NSs).Soft X-ray absorption spectroscopy(sXAS)measurements reveal that in a-CoFeO_(x) nanosheets,the ligand field symmetry around Co atoms is dominated by a T_(d) coordination,in contrast to the O_(h) coordination in the crystalline state,which introduces T_(d)-T_(d) connection.Density functional theory(DFT)calculations confirm that the T_(d)-T_(d) connection in a-CoFeO_(x) structure significantly strengthens electron transfer to activate PMS,which exhibited a first-order kinetic constant(k_(obs))of 0.27 min^(-1) for sulfamethoxazole(SMX)removal with high stability.This study reveals that the phase-engineered CUS can further enhance catalytic activity and provides a simple and scalable strategy for optimizing spinel-type catalysts.
基金supported by the National Key R&D Program of China (2017YFA0208300)the National Natural Science Foundation of China (21522107, 21671180, 21521091, 21390393, U1463202, and 21522305)
文摘Tremendous efforts have been devoted to explore energy-efficient strategies of ammonia synthesis to replace Haber-Bosch process which accounts for 1.4% of the annual energy consumption. In this study, atomically dispersed Au_1 catalyst is synthesized and applied in electrochemical synthesis of ammonia under ambient conditions. A high NH＋4 Faradaic efficiency of 11.1 % achieved by our Au_1 catalyst surpasses most of reported catalysts under comparable conditions. Benefiting from efficient atom utilization, an NH＋4 yield rate of 1,305 μg h-1 mg-1Au has been reached, which is roughly 22.5 times as high as that by sup- ported Au nanoparticles. We also demonstrate that by employing our Au_1 catalyst, NH＋4 can be electro- chemically produced directly from N_2 and H_2 with an energy utilization rate of 4.02 mmol kJ-1. Our study provides a possibility of replacing the Haber-Bosch process with environmentally benign and energy-efficient electrochemical strategies.
文摘Nitrite-dependent anaerobic methane-oxidiz- ing （n-damo） bacteria and anaerobic ammonia oxidizing （anammox） bacteria are two groups of microorganisms involved in global carbon and nitrogen cycling. In order to test whether the n-damo and anammox bacteria co-occur in natural saline environments, the DNA and cDNA samples obtained from the surficial sediments of two saline lakes （with salinity of 32 and 84 g/L, respectively） on the Tibetan Plateau were PCR-amplified with the use of anammox- and n-damo-specific primer sets, followed by clone library construction and phylogenetic analysis. DNA and cDNA- based clones affiliated with n-damo and anammox bacteria were successfully retrieved from the two samples, indicating that these two groups of bacteria can co-occur in natural saline environments with salinity as high as 84g/L. Our finding has great implications for our understanding of the global carbon and nitrogen cycle in nature.
基金supported by grants from the National Natural Science Foundation of China(Nos.82100158,81890994,81770143,81970130,and 81861148030)Double First-Class Project(No.WF510162602)from the Ministry of Education+8 种基金State Key Laboratory of Medical Genomics,Overseas Expertise Introduction Project for Discipline Innovation(111 Project,No.B17029)National Key R&D Program of China(Nos.2019YFA0905902 and 2018YFA0107802)Natural Science Foundation of Shanghai(Nos.20JC1410600,21ZR1480900,and 21YF1427900)Shanghai Clinical Research Center for Hematologic Disease(No.19MC1910700)Shanghai Major Project for Clinical Medicine(No.2017ZZ01002)Shanghai Shenkang Hospital Development Center(No.SHDC2020CR5002)Innovative Research Team of High-level Local Universities in Shanghai,Shanghai Collaborative Innovation Program on Regenerative Medicine and Stem Cell Research(No.2019CXJQ01)Shanghai Jiao Tong University(No.YG2021QN19)Shanghai Guangci Translational Medical Research Development Foundation.
文摘With the recent ongoing autumn/winter 2022 COVID-19 wave and the adjustment of public health control measures,there have been widespread SARS-CoV-2 infections in Chinese mainland.Here we have analyzed 369 viral genomes from recently diagnosed COVID-19 patients in Shanghai,identifying a large number of sublineages of the SARS-CoV-2 Omicron family.Phylogenetic analysis,coupled with contact history tracing,revealed simultaneous community transmission of two Omicron sublineages dominating the infections in some areas of China(BA.5.2 mainly in Guangzhou and Shanghai,and BF.7 mainly in Beijing)and two highly infectious sublineages recently imported from abroad(XBB and BQ.1).Publicly available data from August 31 to November 29,2022 indicated an overall severe/critical case rate of 0.035%nationwide,while analysis of 5706 symptomatic patients treated at the Shanghai Public Health Center between September 1 and December 26,2022 showed that 20 cases(0.35%)without comorbidities progressed into severe/critical conditions and 153 cases(2.68%)with COVID-19-exacerbated comorbidities progressed into severe/critical conditions.These observations shall alert healthcare providers to place more resources for the treatment of severe/critical cases.Furthermore,mathematical modeling predicts this autumn/winter wave might pass through major cities in China by the end of the year,whereas some middle and western provinces and rural areas would be hit by the upcoming infection wave in mid-to-late January 2023,and the duration and magnitude of upcoming outbreak could be dramatically enhanced by the extensive travels during the Spring Festival(January 21,2023).Altogether,these preliminary data highlight the needs to allocate resources to early diagnosis and effective treatment of severe cases and the protection of vulnerable population,especially in the rural areas,to ensure the country’s smooth exit from the ongoing pandemic and accelerate socio-economic recovery.
基金supported by the National Key R&D Program of China(No.2018YFA0702001)the National Natural Science Foundation of China(Nos.22371268 and 22301287)+4 种基金Fundamental Research Funds for the Central Universities(No.WK2060000016)Anhui Provincial Natural Science Foundation(Nos.2208085J09 and 2208085QB33)Collaborative Innovation Program of Hefei Science Center,CAS(No.2022HSC-CIP020)Youth Innovation Promotion Association of the Chinese Academy of Science(No.2018494)USTC Tang Scholar.
文摘The electrochemical CO_(2) reduction reaction(CO_(2)RR)holds significant promise in advancing carbon neutrality.Developing catalysts for the electrochemical CO_(2)RR to multi-carbon(C_(2+))products(e.g.,C_(2)H_(4))under industrial-level current density is urgently needed and pivotal.Herein,we report the Cu_(2)O nanoparticles doped with interstitial carbon atoms(denoted as C-Cu_(2)O NPs)for the conversion of CO_(2) to C_(2+)products.The interstitial carbon promotes the C-Cu_(2)O NPs to possess abundant unsaturated Cu–O bonds,leading to a high-density Cu^(δ+)(0<δ<1)species.The obtained C-Cu_(2)O NPs exhibited significant Faradic efficiency(FE)of C_(2+) products approaching 76.9%and a partial current density reaching 615.2 mA·cm^(–2)under an industrial-level current density of 800 mA·cm^(–2).Furthermore,the efficient electrosynthesis of C_(2)H_(4) achieved an FE of 57.4%with a partial current density of 459.2 mA·cm^(–2).In situ electrochemical attenuated total reflection Fourier transform infrared spectroscopy and in situ Raman spectroscopy analyses revealed that C-Cu_(2)O NPs stabilized the intermediate*CO and facilitated C–C coupling,leading to increased selectivity towards C_(2+) products.
基金supported by the National Key R&D Program of China(Nos.2017YFA0700104 and 2018YFA0702001)the National Natural Science Foundation of China(Nos.21871238 and 22175163)+1 种基金the Fundamental Research Funds for the Central Universities(No.WK2060000016)the Youth Innovation Promotion Association of the Chinese Academy of Science(No.2018494).
文摘Manipulating the oxidation state of Cu catalysts can significantly affect the selectivity and activity of electrocatalytic carbon dioxide reduction(CO_(2)RR).However,the thermodynamically favorable cathodic reduction to metallic states typically leads to catalytic deactivation.Herein,a defect construction strategy is employed to prepare crystalline/amorphous Cu_(2+1)O/CuO_(x)heterostructures(c/a-CuO_(x))with abundant Cu0 and Cuδ+(0<δ<1)sites for CO_(2)RR.The C^(2+)Faradaic efficiency of the heterostructured Cu catalyst is up to 81.3%,with partial current densities of 406.7 mA·cm−2.Significantly,real-time monitoring of the Cu oxidation state evolution by in-situ Raman spectroscopy confirms the stability of Cuδ+species under long-term high current density operation.Density functional theory(DFT)calculations further reveal that the adjacent Cu0 and Cuδ+sites in heterostructured c/a-CuO_(x)can efficiently reduce the energy barrier of CO coupling for C^(2+)products.
基金This work was supported by Science and Technology Key Project of Guangdong Province of China(No.2020B010188002)the National Major Science and Technology Program for Water Pollution Control and Treatment of China(No.2017ZX07202)。
文摘The rational fabrication of highly efficient electrocatalysts with low cost toward oxygen evolution reaction(OER)is greatly desired but remains a formidable challenge.In this work,we present a facile and straightforward method of incorporating NiCo-layered double hydroxide(NiCo-LDH)into GO-dispersed CNTs(GO-CNTs)with interconnected configuration.X-ray absorption spectroscopy(XAS)reveals the strong electron interaction between NiCo-LDH and the underlying GO-CNTs substrate,which is supposed to facilitate charge transfer and accelerate the kinetics for OER.By tuning the amount of CNTs,the optimized NiCo-LDH/GO-CNTs composite can achieve a low overpotential of 290 mV at 10 mA·cm^(−2) current density,a small Tafel slope of 66.8 mV·dec^(−1) and robust stability,superior to the pure NiCo-LDH and commercial RuO_(2) in alkaline media.The preeminent oxygen evolution performance is attributed to the synergistic effect stemming from the merits and the intimate electron interaction between LDH and GO-CNTs.This allows NiCo-LDH/GO-CNTs to be potentially applied in an industrial non-noble metal-based water electrolyzer as the anodic catalysts.
基金Anhui Province for Outstanding Youth,Grant/Award Number:2208085J09Anhui Development and Reform Commission,Grant/Award Number:AHZDCYCX-2SDT2023-07+7 种基金National Key R&D Program of China,Grant/Award Number:2018YFA0702001Postdoctoral Fellowship Program of CPSF,Grant/Award Number:GZC20232511USTC Tang ScholarYouth Innovation Promotion Association of the Chinese Academy of Science,Grant/Award Number:2018494Fundamental Research Funds for the Central Universities,Grant/Award Number:WK2060000016Collaborative Innovation Program of Hefei Science Center,CAS,Grant/Award Number:2022HSC-CIP020National Natural Science Foundation of China,Grant/Award Numbers:22301287,22371268China Postdoctoral Science Foundation,Grant/Award Number:2023M743348。
文摘To unveil the nature of amorphous states,single-element amorphous metals have been the perfect research subject due to the simplest composition.However,the extreme crystal nucleation and growth rate in single-element metal make the synthesis of single-element amorphous metals seemingly impossible in the past.Fortunately,benefited by several delicate synthetic strategies developed recently,the single-element amorphous metals have been successfully demonstrated.This review aims to provide a systematic overview of the synthesis of single-element amorphous metals covering the challenges in physics and recent achieve-ments.In addition,current understanding of the atomic and electronic structures of single-element amorphous metal has also been included.Finally,the challenges that worth further investigation are discussed.By identifying the potential avenues for further exploration,this review aims to contribute valuable insights that will propel the cognition of single-element amorphous metals.
基金supported by the National Key R&D Program of China(2017YFA0700104 and 2018YFA0702001)the National Natural Science Foundation of China(21871238)+2 种基金the Fundamental Research Funds for the Central Universities(WK2060000016)Natural Science Foundation of Anhui Province(2208085J09)USTC Tang Scholar。
