The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Eff...The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.展开更多
Layered sodium trititanate(Na_(2)Ti_(3)O_(7),NTO)is a promising anode material for sodium-ion batteries(NIBs)for large-scale energy storage applications because of its relatively low charge potential and low cost.Howe...Layered sodium trititanate(Na_(2)Ti_(3)O_(7),NTO)is a promising anode material for sodium-ion batteries(NIBs)for large-scale energy storage applications because of its relatively low charge potential and low cost.However,NTO suffers from unsatisfactory structural stability against cycling and poor electron conductivity.Herein,an isovalent doping strategy using Sn^(4+)to partially replace Ti^(4+)is demonstrated for improving the cycling stability and rate capability of NTO.The isovalent doping of Sn^(4+)does not alter the valence state of Ti^(4+),thus maintaining the lattice integrality and structural stability.Moreover,the Sn^(4+)dopant creates more Na^(+)-preferable travel channels and expands the interlayer spacing,thus increasing Na^(+)diffusivity.As a result,a Sn^(4+)-doped Na_(2)Ti_(3)O_7(NSTO)electrode exhibits a reversible Na^(+)storage specific capacity of 176 mA h g^(-1)at 0.1C and an ultra-long cycling life with 80.2%capacity retention after5000 cycles at 1C,far outperforming the undoped and aliovalent-doping NTO electrodes reported in the literature.In addition,the NSTO electrode delivers a rate capability of 102 mA h g^(-1)at 5C,higher than that of the NTO electrode(62 mA h g^(-1)).In situ X-ray diffraction characterization results reveal that Na^(+)storage in NSTO undergoes a partial solid-solution reaction mechanism,which is completely different from the two-phase transition mechanism of NTO.Density functional theory calculation results demonstrate that Sn^(4+)doping strengthens the Ti-O bond,contributing to structural stability.This work provides a robust approach to significantly improving the electrochemical performance of NTO-based anode materials for developing long-life NIBs.展开更多
BACKGROUND Cholesterol stones affect a certain subpopulation of children.Concerns have been raised on the impact of gallbladder surgery on the growth of children and adolescents.AIM To study the population characteris...BACKGROUND Cholesterol stones affect a certain subpopulation of children.Concerns have been raised on the impact of gallbladder surgery on the growth of children and adolescents.AIM To study the population characteristics,clinical features,treatment,and prognosis of gallstones in children.METHODS The clinical data of 44 children with gallstones admitted to The First Affiliated Hospital of Naval Medical University from August 2009 to August 2021 were collected,the children were followed up by telephone to monitor their prognoses.The follow-up ended in August 2023.The shortest follow-up time was 2 years and 6 months,whereas the longest was 13 years and 11 months.The population characteristics,general clinical characteristics,and treatments were retrospectively analyzed.The children were divided according to whether they underwent surgical gallbladder removal into an operation group(n=28)and a non-operation group(n=16),The effects of surgical gallbladder resection on the growth and development of children were analyzed.RESULTS The male–female ratio in the population was 6:5 and 84.09%of the children had onset in adolescence.Furthermore,29.55%of the children were overweight or obese.The study identified 26 cases with metabolic abnormalities,9 with hemolytic anemia,and 4 with choledochal cyst.Of the population,68.18%had recurrent symptomatic cholecystolithiasis.Surgical treatment accounted for 63.64%,with laparoscopic cholecystectomy accounting for 71.43%of surgical treatment.No significant differences were observed in symptoms and complications between the surgery and non-surgery groups.Furthermore,no significant differences were found between the two groups in the attainment of genetic height target and the rightward shift of height curve during follow-up.CONCLUSION The sex characteristics of gallstones in children were not observed.Most gallstones occurred in adolescents and rarely in young children.A considerable proportion of children have inborn causes,which are often concurrent with metabolic abnormalities and hemolytic anemia.Most children had recurrent symptomatic gallstones.Surgical treatment,especially laparoscopic cholecystectomy,is still the main treatment for gallstones in children.Surgical treatment did not affect the growth and development of children who underwent gallstone removal.展开更多
Porous materials have attracted great attention in energy and environment applications,such as metal organic frameworks(MOFs),metal aerogels,carbon aerogels,porous metal oxides.These materials could be also hybridized...Porous materials have attracted great attention in energy and environment applications,such as metal organic frameworks(MOFs),metal aerogels,carbon aerogels,porous metal oxides.These materials could be also hybridized with other materials into functional composites with superior properties.The high specific area of porous materials offer them the advantage as hosts to conduct catalytic and electrochemical reactions.On one hand,catalytic reactions include photocatalytic,p ho toe lectrocatalytic and electrocatalytic reactions over some gases.On the other hand,they can be used as electrodes in various batteries,such as alkaline metal ion batteries and electrochemical capacitors.So far,both catalysis and batteries are extremely attractive topics.There are also many obstacles to overcome in the exploration of these porous materials.The research related to porous materials for energy and environment applications is at extremely active stage,and this has motivated us to contribute with a roadmap on ’porous materials for energy and environment applications’.展开更多
Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible ...Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible to oxidative injury, resulting in a propensity for neurodegeneration at later stages. In this study, embryonic neural stem cells obtained from human superoxide dis- mutase 1 mutant （SOD1G93A） and wild-type （SOD1wv） mouse models were exposed to H202. We assayed cell viability with mitochondrial succinic dehydrogenase colorimetric reagent, and measured cell apoptosis by flow cytometry. Moreover, we evaluated the expression of the adenos- ine monophosphate-activated protein kinase （AMPK） ct-subunit, paired box 3 （Pax3） protein, and p53 in western blot analyses. Compared with SOD1wr cells, SOD1~93A embryonic neural stem cells were more likely to undergo H202-induced apoptosis. Phosphorylation of AMPKct in SOD1G93A cells was higher than that in SOD1wr cells. Pax3 expression was inversely correlated with the phosphorylation levels of AMPKct. p53 protein levels were also correlated with AMPKct phosphorylation levels. Compound C, an inhibitor of AMPKa, attenuated the effects of H20~. These results suggest that embryonic neural stem cells from SOD1C93A mice are more susceptible to apoptosis in the presence of oxidative stress compared with those from wild-type controls, and the effects are mainly mediated by Pax3 and p53 in the AMPKa pathway.展开更多
Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public concern.Herein,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of ...Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public concern.Herein,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of 2015–2019 over NCP via 8 scenarios with WRF-Chem model.The simulated mean MDA8 O_(3) in urban areas of 13 major cities in NCP increased by 17.1%∼34.8%,which matched well with the observations(10.8%∼33.1%).Meanwhile,the model could faithfully reproduce the changes in aerosol loads,precursors,and meteorological conditions.A relatively-even O_(3) increase(+1.2%∼+3.9%for 24-h O_(3) and+1.0%∼+3.8%for MDA8 O_(3))was induced by PM_(2.5) dropping,which was consistent with the geographic distribution of regional PM_(2.5) reduction.Meanwhile,the NO_(2) reduction coupled with a nearconstant VOCs led to the elevated VOCs/NOx ratios,and then caused O_(3) rising in the areas under VOCs-limited regimes.Therein,the pronounced increases occurred in Handan,Xingtai,Shijiazhuang,Tangshan,and Langfang(+10.7%∼+13.6%for 24-h O_(3) and+10.2%∼+12.2%forMDA8 O_(3));while the increases in other citieswere 5.7%∼10.5%for 24-h O_(3) and 4.9%∼9.2%for MDA8 O_(3).Besides,the meteorological fluctuations brought about the more noticeable O_(3) increases in northern parts(+12.5%∼+13.5%for 24-h O_(3) and+11.2%∼+12.4%for MDA8 O_(3))than those in southern and central parts(+3.2%∼+9.3%for 24-h O_(3) and+3.7%∼+8.8%for MDA8 O_(3)).The sum of the impacts of the three drivers reached 16.7%∼21.9%,which were comparable to the changes of the observed O_(3).Therefore,exploring reasonable emissionsreduction strategies is essential for the ozone pollution mitigation over this region.展开更多
Gene co-expression analysis has been widely used for predicting gene functions because genes within modules of a co-expression network may be involved in similar biological processes and exhibit similar biological fun...Gene co-expression analysis has been widely used for predicting gene functions because genes within modules of a co-expression network may be involved in similar biological processes and exhibit similar biological functions.To detect gene relationships in the grapevine genome,we constructed a grapevine gene co-expression network(GGCN)by compiling a total of 374 publically available grapevine microarray datasets.The GGCN consisted of 557 modules containing a total of 3834 nodes with 13479 edges.The functions of the subnetwork modules were inferred by Gene ontology(GO)enrichment analysis.In 127 of the 557 modules containing two or more GO terms,38 modules exhibited the most significantly enriched GO terms,including‘protein catabolism process’,‘photosynthesis’,‘cell biosynthesis process’,‘biosynthesis of plant cell wall’,‘stress response’and other important biological processes.The‘response to heat’GO term was highly represented in module 17,which is composed of many heat shock proteins.To further determine the potential functions of genes in module 17,we performed a Pearson correlation coefficient test,analyzed orthologous relationships with Arabidopsis genes and established gene expression correlations with real-time quantitative reverse transcriptase PCR(qRT-PCR).Our results indicated that many genes in module 17 were upregulated during the heat shock and recovery processes and downregulated in response to low temperature.Furthermore,two putative genes,Vit_07s0185g00040 and Vit_02s0025g04060,were highly expressed in response to heat shock and recovery.This study provides insight into GGCN gene modules and offers important references for gene functions and the discovery of new genes at the module level.展开更多
AIM To investigate the abundance and potential functions of LAP^+CD4^+ T cells in colorectal cancer(CRC). METHODS Proportions of LAP^+CD4^+ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC ...AIM To investigate the abundance and potential functions of LAP^+CD4^+ T cells in colorectal cancer(CRC). METHODS Proportions of LAP^+CD4^+ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box(Fox)p3, cytotoxic T-lymphocyte-associated protein(CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP^-CD4^+ and LAP^+CD4^+ T cells were isolated using a magnetic cellsorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor(TGF)-β.RESULTS The proportion of LAP^+CD4^+ T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP^+CD4^+ T cells was significantly higher in tumor tissues(11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP^+CD4^+ T cells and TNM stage(P < 0.001), distant metastasis(P < 0.001) and serum level of carcinoembryonic antigen(P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP^+CD4^+ T cells (95.02% ± 2.87%), which was similar for LAP^-CD4^+ T cells(94.75% ± 2.76%). In contrast to LAP^-CD4^+ T cells, LAP^+CD4^+ T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5(P < 0.01). LAP^+CD4^+ T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAPCD4+ T cells.CONCLUSION LAP^+CD4^+ T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β.展开更多
The microstructures and corrosion behaviors of the Al−6.5Si−0.45Mg casting alloys with the addition of Sc were investigated by using scanning electron microscopy,X-ray diffraction,electrochemical measurement technique...The microstructures and corrosion behaviors of the Al−6.5Si−0.45Mg casting alloys with the addition of Sc were investigated by using scanning electron microscopy,X-ray diffraction,electrochemical measurement techniques and immersion corrosion tests and compared with those of Sr-modified alloy.The results show that Sc has evident refining and modifying effects on the primaryα(Al)and the eutectic Si phase of the alloy,and the effects can be enhanced with the increase of Sc content.When the Sc content is increased to 0.58 wt.%,its modifying effect on the eutectic Si is almost same as that of Sr.Sc can improve the corrosion resistance of the test alloy in NaCl solution when compared with Sr,but the excessively high Sc content cannot further increase the corrosion resistance of the alloy.The corrosion of the alloys mainly occurs in the eutectic region of the alloy,and mostly the eutecticα(Al)is dissolved.This confirms that Si phase is more noble thanα(Al)phase,and the galvanic couplings can be formed between the eutectic Si andα(Al)phases.展开更多
A new crosslinked polymer,called P65,with appropriate photo-electrochemical,opto-electronic,and thermal properties,has been designed and synthesized as an efficient,dopant-free,hole-transport material(HTM)for n-i-p ty...A new crosslinked polymer,called P65,with appropriate photo-electrochemical,opto-electronic,and thermal properties,has been designed and synthesized as an efficient,dopant-free,hole-transport material(HTM)for n-i-p type planar perovskite solar cells(PSCs).P65 is obtained from a low-cost and easily synthesized spiro[fluorene-9,90-xanthene]-30,60-diol(SFX-OH)-based monomer X65 through a freeradical polymerization reaction.The combination of a three-dimensional(3 D)SFX core unit,holetransport methoxydiphenylamine group,and crosslinked polyvinyl network provides P65 with good solubility and excellent film-forming properties.By employing P65 as a dopant-free hole-transport layer in conventional n-i-p type PSCs,a power conversion efficiency(PCE)of up to 17.7%is achieved.To the best of our knowledge,this is the first time a 3 D,crosslinked,polymeric dopant-free HTM has been reported for use in conventional n-i-p type PSCs.This study provides a new strategy for the future development of a 3 D crosslinked polymeric dopant-free HTM with a simple synthetic route and low-cost for commercial,large-scale applications in future PSCs.展开更多
In recent years the photovoltaic community has witnessed the unprecedented development of perovskite solar cells（PSCs） as they have taken the lead in emergent photovoltaic technologies. The power conversion efficien...In recent years the photovoltaic community has witnessed the unprecedented development of perovskite solar cells（PSCs） as they have taken the lead in emergent photovoltaic technologies. The power conversion efficiency of this new class of solar cells has been increased to a point where they are beginning to compete with more established technologies. Although PSCs have evolved a variety of structures, the use of hole-transporting materials（HTMs） remains indispensable. Here, an overview of the various types of available HTMs is presented. This includes organic and inorganic HTMs and is presented alongside recent progress in associated aspects of PSCs, including device architectures and fabrication techniques to produce high-quality perovskite films. The structure, electrochemistry, and physical properties of a variety of HTMs are discussed, highlighting considerations for those designing new HTMs. Finally, an outlook is presented to provide more concrete direction for the development and optimization of HTMs for highefficiency PSCs.展开更多
Two novel fluorene-based hole transporting materials (HTMs) were synthesized to be used in perovskite solar cells (PSCs). C102 was designed based on C101 by simply linking the two carb on-carbon single bonds to compos...Two novel fluorene-based hole transporting materials (HTMs) were synthesized to be used in perovskite solar cells (PSCs). C102 was designed based on C101 by simply linking the two carb on-carbon single bonds to compose a "dispiro" structure. Their typically similar structures cause them sharing almost the same energy levels. However, their photovoltaic performances are quite different due to the small variations. The PSC that contained the "dispiro" structure, C102, reached a power conversion efficiency (PCE) of 17.4%, while the device contained C101, obtained a lower PCE of 15.5%. Electrochemical properties and Photovoltaic characterization of the two materials have been investigated to explain the result. It is shown that C102 has a stronger ability to transport holes and resist the charge recombination. Thus, the dispiro structure should be more appropriate being used as HTM in PSCs.展开更多
As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in...As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in multi-path fading channel. However, when there are frequency offsets during the signal transmission, the inter-carrier interference （ICI） is introduced, which significantly degrades the performance. The existing ICI self-cancellation schemes such as PCC-OFDM are not optimum to minimize the interference considering both noise and ICI. In this paper, a new metric named S1NR （signal-to-interference- and-noise ratio） is proposed. We discuss the optimization issue when a constant frequency offset exists and in time-varying channels. The optimum weighting-coefficient-pair （OWCP） is obtained, which maximizes SINR theoretically through the alternant iteration algorithm. Simulations show that the performance of OWCP-OFDM is better than that of PCC-OFDM, especially when the frequency offset is large. Although the ICI self-cancellation scheme suffers bandwidth inefficiency, from the simulation results we can also see that the performance of OWCP-OFDM is much better than that of the standard OFDM systems with the same bandwidth efficiency when a frequency offset exists. Moreover, since the redundant modulation provides the capability to suppress ICI as well as a receiving SNR gain, it can be considered as exchanging the bandwidth for SNR.展开更多
Diabetic patients often exhibit delayed or incomplete progress in the healing of acute wounds,owing to poor blood perfusion.Platelet-rich plasma(PRP)has attracted much attention as a means to improve wound healing,bec...Diabetic patients often exhibit delayed or incomplete progress in the healing of acute wounds,owing to poor blood perfusion.Platelet-rich plasma(PRP)has attracted much attention as a means to improve wound healing,because it contains high growth factor concentrations.However,the burst-like release of PRP growth factors results in a short halflife of these therapeutic proteins,thus greatly limiting the therapeutic effect.In this study,we prepared PRP from human umbilical cord blood and developed an in situ photocrosslinkable PRP hydrogel glue(HNPRP)by adding a photoresponsive hyaluronic acid(HA-NB)into PRP.The HNPRP hydrogel allowed for controlled release of plateletderived growth factor-BB(PDGF-BB)and transforming growth factor-β(TGF-β)for up to 28 days.In vitro cell culture showed that HNPRP promoted migration of fibroblasts and keratinocytes as well as PRP and did not reveal the advantages of HNPRP.However,in a diabetic rat skin wound model,HNPRP treatment promoted faster wound closure.Furthermore,the HNPRP group,compared with the control,PRP and hydrogel only groups,showed significantly greater re-epithelialization and numbers of both newly formed and mature blood vessels.The HNPRP group also displayed higher collagen formation than did the control group.In conclusion,HNPRP enhances angiogenesis and skin regeneration and consequently achieves faster wound healing,thus extending its potential for clinical applications to treat diabetic skin wounds.展开更多
OBJECTIVE To study the gene expression profiles of human endometrial cancers at various differentia0ted grade levels and to identify the genes related to differentiation of the endometrial cancers. METHODS cDNA microa...OBJECTIVE To study the gene expression profiles of human endometrial cancers at various differentia0ted grade levels and to identify the genes related to differentiation of the endometrial cancers. METHODS cDNA microarray technology was used to analyze the differentially-expressed genes among different differentiated grades of 32 cases of endometrial cancer. Hierarchical cluster analysis （HCA） for the gene expression profiles of the cases was employed. RESULTS The tissue samples were grouped based on the various differentiated tumor grades with 33 differentiation-related genes identified out （P〈0.001）. Based on the results from the HCA, the conformity rate was 91% among the 33 differentially-expressed genes, and the analysis of pathological classification.CONCLUSION Genes related to the differentiation of endometrial cancer can be identified by using gene chips to analyze the expression profiles of endometrial cancers at various differentiated grades; HCA of the gene expression profiles can be helpful for distinguishing high-risk endometrial cancers before surgery.展开更多
There is a close relationship between crassulacean acid metabolism and drought tolerance,and a great number of landscape plants which consume less water are necessary to build economic garden.In order to provide the b...There is a close relationship between crassulacean acid metabolism and drought tolerance,and a great number of landscape plants which consume less water are necessary to build economic garden.In order to provide the basis for selecting drought-tolerant landscape plants,five species of plants were employed,including Dendrobium chrysotoxum,D.nobile,D.primulinum,Kalanchoblossfeldiana and K.daigremontiana.Exposed to different intensities of light,various samples were collected.The slices were prepared via different techniques.Stomatal movements and stomatal complex structures were observed by scanning electronic microscope and confocal laser scanning microscope.The results indicated that the slices made rapidly from fresh leaves were conductive to inspecting actual stomatal movements and stomatal complex structures as soon as possible.It was found that the stomatal movement of K.daigremontiana,K.blossfeldiana and D.primulinum displayed typical characteristics of crassulacean acid metabolism,while that of D.chrysotoxum and D.nobile did not exhibited obvious characteristics of crassulacean acid metabolism.展开更多
The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear pow...The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear power more objectively.This paper aims to explore the impact of nuclear events on NPD pathway planning.The influence of nuclear events is quantified as a monetary risk component,and an optimization model that incorporates the NER in the objective function is proposed.To optimize the pathway of NPD in the lowcarbon transition course of power supply structure evolution,a simulation model is built to deduce alternative NPD pathways and corresponding power supply evolution scenarios under the constraint of an exogenously assigned carbon emission pathway(CEP);moreover,a method is proposed to describe the CEP by superimposing the maximum carbon emission space and each carbon emission reduction(CER)component,and various CER components are clustered considering the emission reduction characteristics and resource endowments of different power generation technologies.A case study is conducted to explore the impact of NER and its risk valuation uncertainty on NPD pathway planning.The method presented in this paper allows the impact of nuclear events on NPD pathway planning to be quantified and improves the level of coordinated optimization of benefits and risks.展开更多
基金supported by the National Natural Science Foundation of China(22179034,22279030)the Natural Science Foundation of Heilongjiang Province(ZD2023B002).
文摘The susceptibility of Pt catalyst surfaces to carbon monoxide(CO)poisoning in anodic hydrogen oxidation reaction(HOR)has been a critical constraint on the development of proton exchange membrane fuel cells(PEMFCs).Effectively regulating the electronic structure of Pt to enhance CO resistance is crucial for developing high-performance catalysts with robust anti-poisoning capabilities.Herein,the Pt/W@NCNF featured by Pt nanoparticles and atomical dispersed tungsten(W)sites on N-doped carbon nanofibers is developed for CO tolerance HOR catalyst.The presence of W enables the electron transfer from Pt,which promotes electron rearrangement in the Pt-5d orbitals.It not only optimizes the adsorption of H^(*) and CO^(*)on Pt,but also the OH^(*) intermediates adsorbed on the W sites oxidize the CO*adsorbed on Pt,thereby retaining more active sites for H_(2) adsorption and oxidation.The HOR exchange current density of Pt/W@NCNF reaches 1.35 times that of commercial Pt/C,and the limiting current density decreases by only 3.4%after introducing 1000 ppm CO in H_(2).Notably,the Pt/W@NCNF-based PEMFCs deliver markedly superior performance across a range of CO concentrations.The present study demonstrates that electronic modulation of Pt is an effective strategy for simultaneously achieving resistance to CO and promoted HOR activity.
基金supported by the Natural Science Foundation of Shandong Province(ZR2022QB025 and ZR2021QF070)the Start-up Foundation of Qingdao University(DC2000005025)。
文摘Layered sodium trititanate(Na_(2)Ti_(3)O_(7),NTO)is a promising anode material for sodium-ion batteries(NIBs)for large-scale energy storage applications because of its relatively low charge potential and low cost.However,NTO suffers from unsatisfactory structural stability against cycling and poor electron conductivity.Herein,an isovalent doping strategy using Sn^(4+)to partially replace Ti^(4+)is demonstrated for improving the cycling stability and rate capability of NTO.The isovalent doping of Sn^(4+)does not alter the valence state of Ti^(4+),thus maintaining the lattice integrality and structural stability.Moreover,the Sn^(4+)dopant creates more Na^(+)-preferable travel channels and expands the interlayer spacing,thus increasing Na^(+)diffusivity.As a result,a Sn^(4+)-doped Na_(2)Ti_(3)O_7(NSTO)electrode exhibits a reversible Na^(+)storage specific capacity of 176 mA h g^(-1)at 0.1C and an ultra-long cycling life with 80.2%capacity retention after5000 cycles at 1C,far outperforming the undoped and aliovalent-doping NTO electrodes reported in the literature.In addition,the NSTO electrode delivers a rate capability of 102 mA h g^(-1)at 5C,higher than that of the NTO electrode(62 mA h g^(-1)).In situ X-ray diffraction characterization results reveal that Na^(+)storage in NSTO undergoes a partial solid-solution reaction mechanism,which is completely different from the two-phase transition mechanism of NTO.Density functional theory calculation results demonstrate that Sn^(4+)doping strengthens the Ti-O bond,contributing to structural stability.This work provides a robust approach to significantly improving the electrochemical performance of NTO-based anode materials for developing long-life NIBs.
文摘BACKGROUND Cholesterol stones affect a certain subpopulation of children.Concerns have been raised on the impact of gallbladder surgery on the growth of children and adolescents.AIM To study the population characteristics,clinical features,treatment,and prognosis of gallstones in children.METHODS The clinical data of 44 children with gallstones admitted to The First Affiliated Hospital of Naval Medical University from August 2009 to August 2021 were collected,the children were followed up by telephone to monitor their prognoses.The follow-up ended in August 2023.The shortest follow-up time was 2 years and 6 months,whereas the longest was 13 years and 11 months.The population characteristics,general clinical characteristics,and treatments were retrospectively analyzed.The children were divided according to whether they underwent surgical gallbladder removal into an operation group(n=28)and a non-operation group(n=16),The effects of surgical gallbladder resection on the growth and development of children were analyzed.RESULTS The male–female ratio in the population was 6:5 and 84.09%of the children had onset in adolescence.Furthermore,29.55%of the children were overweight or obese.The study identified 26 cases with metabolic abnormalities,9 with hemolytic anemia,and 4 with choledochal cyst.Of the population,68.18%had recurrent symptomatic cholecystolithiasis.Surgical treatment accounted for 63.64%,with laparoscopic cholecystectomy accounting for 71.43%of surgical treatment.No significant differences were observed in symptoms and complications between the surgery and non-surgery groups.Furthermore,no significant differences were found between the two groups in the attainment of genetic height target and the rightward shift of height curve during follow-up.CONCLUSION The sex characteristics of gallstones in children were not observed.Most gallstones occurred in adolescents and rarely in young children.A considerable proportion of children have inborn causes,which are often concurrent with metabolic abnormalities and hemolytic anemia.Most children had recurrent symptomatic gallstones.Surgical treatment,especially laparoscopic cholecystectomy,is still the main treatment for gallstones in children.Surgical treatment did not affect the growth and development of children who underwent gallstone removal.
基金financially support by an Australian Research Council (ARC) Discovery Project (No. DP200100965)a Griffith University Postdoctoral Fellowship
文摘Porous materials have attracted great attention in energy and environment applications,such as metal organic frameworks(MOFs),metal aerogels,carbon aerogels,porous metal oxides.These materials could be also hybridized with other materials into functional composites with superior properties.The high specific area of porous materials offer them the advantage as hosts to conduct catalytic and electrochemical reactions.On one hand,catalytic reactions include photocatalytic,p ho toe lectrocatalytic and electrocatalytic reactions over some gases.On the other hand,they can be used as electrodes in various batteries,such as alkaline metal ion batteries and electrochemical capacitors.So far,both catalysis and batteries are extremely attractive topics.There are also many obstacles to overcome in the exploration of these porous materials.The research related to porous materials for energy and environment applications is at extremely active stage,and this has motivated us to contribute with a roadmap on ’porous materials for energy and environment applications’.
基金supported by a grant from the National Natural Sciences Foundation of China,No.81030019
文摘Alterations in embryonic neural stem cells play crucial roles in the pathogenesis of amyotrophic lateral sclerosis. We hypothesized that embryonic neural stem cells from SOD1G93A individuals might be more susceptible to oxidative injury, resulting in a propensity for neurodegeneration at later stages. In this study, embryonic neural stem cells obtained from human superoxide dis- mutase 1 mutant （SOD1G93A） and wild-type （SOD1wv） mouse models were exposed to H202. We assayed cell viability with mitochondrial succinic dehydrogenase colorimetric reagent, and measured cell apoptosis by flow cytometry. Moreover, we evaluated the expression of the adenos- ine monophosphate-activated protein kinase （AMPK） ct-subunit, paired box 3 （Pax3） protein, and p53 in western blot analyses. Compared with SOD1wr cells, SOD1~93A embryonic neural stem cells were more likely to undergo H202-induced apoptosis. Phosphorylation of AMPKct in SOD1G93A cells was higher than that in SOD1wr cells. Pax3 expression was inversely correlated with the phosphorylation levels of AMPKct. p53 protein levels were also correlated with AMPKct phosphorylation levels. Compound C, an inhibitor of AMPKa, attenuated the effects of H20~. These results suggest that embryonic neural stem cells from SOD1C93A mice are more susceptible to apoptosis in the presence of oxidative stress compared with those from wild-type controls, and the effects are mainly mediated by Pax3 and p53 in the AMPKa pathway.
基金supported by the National Natural Science Foundation of China(Nos.51978010,52022005).
文摘Continuous aggravated surface O_(3) over North China Plain(NCP)has attracted widely public concern.Herein,we evaluated the effects of changes in aerosols,precursor emissions,and meteorology on O_(3) in summer(June)of 2015–2019 over NCP via 8 scenarios with WRF-Chem model.The simulated mean MDA8 O_(3) in urban areas of 13 major cities in NCP increased by 17.1%∼34.8%,which matched well with the observations(10.8%∼33.1%).Meanwhile,the model could faithfully reproduce the changes in aerosol loads,precursors,and meteorological conditions.A relatively-even O_(3) increase(+1.2%∼+3.9%for 24-h O_(3) and+1.0%∼+3.8%for MDA8 O_(3))was induced by PM_(2.5) dropping,which was consistent with the geographic distribution of regional PM_(2.5) reduction.Meanwhile,the NO_(2) reduction coupled with a nearconstant VOCs led to the elevated VOCs/NOx ratios,and then caused O_(3) rising in the areas under VOCs-limited regimes.Therein,the pronounced increases occurred in Handan,Xingtai,Shijiazhuang,Tangshan,and Langfang(+10.7%∼+13.6%for 24-h O_(3) and+10.2%∼+12.2%forMDA8 O_(3));while the increases in other citieswere 5.7%∼10.5%for 24-h O_(3) and 4.9%∼9.2%for MDA8 O_(3).Besides,the meteorological fluctuations brought about the more noticeable O_(3) increases in northern parts(+12.5%∼+13.5%for 24-h O_(3) and+11.2%∼+12.4%for MDA8 O_(3))than those in southern and central parts(+3.2%∼+9.3%for 24-h O_(3) and+3.7%∼+8.8%for MDA8 O_(3)).The sum of the impacts of the three drivers reached 16.7%∼21.9%,which were comparable to the changes of the observed O_(3).Therefore,exploring reasonable emissionsreduction strategies is essential for the ozone pollution mitigation over this region.
基金This research was supported by the Chinese National Natural Science Foundation Project#31201607.
文摘Gene co-expression analysis has been widely used for predicting gene functions because genes within modules of a co-expression network may be involved in similar biological processes and exhibit similar biological functions.To detect gene relationships in the grapevine genome,we constructed a grapevine gene co-expression network(GGCN)by compiling a total of 374 publically available grapevine microarray datasets.The GGCN consisted of 557 modules containing a total of 3834 nodes with 13479 edges.The functions of the subnetwork modules were inferred by Gene ontology(GO)enrichment analysis.In 127 of the 557 modules containing two or more GO terms,38 modules exhibited the most significantly enriched GO terms,including‘protein catabolism process’,‘photosynthesis’,‘cell biosynthesis process’,‘biosynthesis of plant cell wall’,‘stress response’and other important biological processes.The‘response to heat’GO term was highly represented in module 17,which is composed of many heat shock proteins.To further determine the potential functions of genes in module 17,we performed a Pearson correlation coefficient test,analyzed orthologous relationships with Arabidopsis genes and established gene expression correlations with real-time quantitative reverse transcriptase PCR(qRT-PCR).Our results indicated that many genes in module 17 were upregulated during the heat shock and recovery processes and downregulated in response to low temperature.Furthermore,two putative genes,Vit_07s0185g00040 and Vit_02s0025g04060,were highly expressed in response to heat shock and recovery.This study provides insight into GGCN gene modules and offers important references for gene functions and the discovery of new genes at the module level.
基金Supported by the National Natural Science Foundation of China,No.81260316
文摘AIM To investigate the abundance and potential functions of LAP^+CD4^+ T cells in colorectal cancer(CRC). METHODS Proportions of LAP^+CD4^+ T cells were examined in peripheral blood and tumor/paratumor tissues of CRC patients and healthy controls using flow cytometry. Expression of phenotypic markers such as forkhead box(Fox)p3, cytotoxic T-lymphocyte-associated protein(CTLA)-4, chemokine CC receptor (CCR)4 and CCR5 was measured using flow cytometry. LAP^-CD4^+ and LAP^+CD4^+ T cells were isolated using a magnetic cellsorting system and cell purity was analyzed by flow cytometry. Real-time quantitative polymerase chain reaction was used to measure expression of cytokines interleukin (IL)-10 and transforming growth factor(TGF)-β.RESULTS The proportion of LAP^+CD4^+ T cells was significantly higher in peripheral blood from patients (9.44% ± 3.18%) than healthy controls (1.49% ± 1.00%, P < 0.001). Among patients, the proportion of LAP^+CD4^+ T cells was significantly higher in tumor tissues(11.76% ± 3.74%) compared with paratumor tissues (3.87% ± 1.64%, P < 0.001). We also observed positive correlations between the proportion of LAP^+CD4^+ T cells and TNM stage(P < 0.001), distant metastasis(P < 0.001) and serum level of carcinoembryonic antigen(P < 0.05). Magnetic-activated cell sorting gave an overall enrichment of LAP^+CD4^+ T cells (95.02% ± 2.87%), which was similar for LAP^-CD4^+ T cells(94.75% ± 2.76%). In contrast to LAP^-CD4^+ T cells, LAP^+CD4^+ T cells showed lower Foxp3 expression but significantly higher levels of CTLA-4, CCR4 and CCR5(P < 0.01). LAP^+CD4^+ T cells expressed significantly larger amounts of IL-10 and TGF-β but lower levels of IL-2, IL-4, IL-17 and interferon-γ, compared with LAPCD4+ T cells.CONCLUSION LAP^+CD4^+ T cells accumulated in the tumor microenvironment of CRC patients and were involved in immune evasion mediated by IL-10 and TGF-β.
文摘The microstructures and corrosion behaviors of the Al−6.5Si−0.45Mg casting alloys with the addition of Sc were investigated by using scanning electron microscopy,X-ray diffraction,electrochemical measurement techniques and immersion corrosion tests and compared with those of Sr-modified alloy.The results show that Sc has evident refining and modifying effects on the primaryα(Al)and the eutectic Si phase of the alloy,and the effects can be enhanced with the increase of Sc content.When the Sc content is increased to 0.58 wt.%,its modifying effect on the eutectic Si is almost same as that of Sr.Sc can improve the corrosion resistance of the test alloy in NaCl solution when compared with Sr,but the excessively high Sc content cannot further increase the corrosion resistance of the alloy.The corrosion of the alloys mainly occurs in the eutectic region of the alloy,and mostly the eutecticα(Al)is dissolved.This confirms that Si phase is more noble thanα(Al)phase,and the galvanic couplings can be formed between the eutectic Si andα(Al)phases.
基金the support of the Swedish Energy Agency and Swedish Foundation for Strategic Research(SSF)for their financial supportthe China Scholarship Council(CSC)for its financial support。
文摘A new crosslinked polymer,called P65,with appropriate photo-electrochemical,opto-electronic,and thermal properties,has been designed and synthesized as an efficient,dopant-free,hole-transport material(HTM)for n-i-p type planar perovskite solar cells(PSCs).P65 is obtained from a low-cost and easily synthesized spiro[fluorene-9,90-xanthene]-30,60-diol(SFX-OH)-based monomer X65 through a freeradical polymerization reaction.The combination of a three-dimensional(3 D)SFX core unit,holetransport methoxydiphenylamine group,and crosslinked polyvinyl network provides P65 with good solubility and excellent film-forming properties.By employing P65 as a dopant-free hole-transport layer in conventional n-i-p type PSCs,a power conversion efficiency(PCE)of up to 17.7%is achieved.To the best of our knowledge,this is the first time a 3 D,crosslinked,polymeric dopant-free HTM has been reported for use in conventional n-i-p type PSCs.This study provides a new strategy for the future development of a 3 D crosslinked polymeric dopant-free HTM with a simple synthetic route and low-cost for commercial,large-scale applications in future PSCs.
基金financial support from the Natural Science Foundation of China (grant numbers: 51661135021, 21606039, 91233201, and 21276044)
文摘In recent years the photovoltaic community has witnessed the unprecedented development of perovskite solar cells（PSCs） as they have taken the lead in emergent photovoltaic technologies. The power conversion efficiency of this new class of solar cells has been increased to a point where they are beginning to compete with more established technologies. Although PSCs have evolved a variety of structures, the use of hole-transporting materials（HTMs） remains indispensable. Here, an overview of the various types of available HTMs is presented. This includes organic and inorganic HTMs and is presented alongside recent progress in associated aspects of PSCs, including device architectures and fabrication techniques to produce high-quality perovskite films. The structure, electrochemistry, and physical properties of a variety of HTMs are discussed, highlighting considerations for those designing new HTMs. Finally, an outlook is presented to provide more concrete direction for the development and optimization of HTMs for highefficiency PSCs.
基金the National Natural Science Foundation of China(Nos.51661135021,21606039,21507008,91233201,and 21276044)for financial support
文摘Two novel fluorene-based hole transporting materials (HTMs) were synthesized to be used in perovskite solar cells (PSCs). C102 was designed based on C101 by simply linking the two carb on-carbon single bonds to compose a "dispiro" structure. Their typically similar structures cause them sharing almost the same energy levels. However, their photovoltaic performances are quite different due to the small variations. The PSC that contained the "dispiro" structure, C102, reached a power conversion efficiency (PCE) of 17.4%, while the device contained C101, obtained a lower PCE of 15.5%. Electrochemical properties and Photovoltaic characterization of the two materials have been investigated to explain the result. It is shown that C102 has a stronger ability to transport holes and resist the charge recombination. Thus, the dispiro structure should be more appropriate being used as HTM in PSCs.
基金Project (No. 2006AA01Z273) supported by the Hi-Tech ResearchDevelopment Program (863) of China
文摘As one of the most important components of the wideband wireless access technique, orthogonal frequency division multiplexing （OFDM） has a high usage rate of spectrum and combats inter-symbol interference （ISI） in multi-path fading channel. However, when there are frequency offsets during the signal transmission, the inter-carrier interference （ICI） is introduced, which significantly degrades the performance. The existing ICI self-cancellation schemes such as PCC-OFDM are not optimum to minimize the interference considering both noise and ICI. In this paper, a new metric named S1NR （signal-to-interference- and-noise ratio） is proposed. We discuss the optimization issue when a constant frequency offset exists and in time-varying channels. The optimum weighting-coefficient-pair （OWCP） is obtained, which maximizes SINR theoretically through the alternant iteration algorithm. Simulations show that the performance of OWCP-OFDM is better than that of PCC-OFDM, especially when the frequency offset is large. Although the ICI self-cancellation scheme suffers bandwidth inefficiency, from the simulation results we can also see that the performance of OWCP-OFDM is much better than that of the standard OFDM systems with the same bandwidth efficiency when a frequency offset exists. Moreover, since the redundant modulation provides the capability to suppress ICI as well as a receiving SNR gain, it can be considered as exchanging the bandwidth for SNR.
文摘Diabetic patients often exhibit delayed or incomplete progress in the healing of acute wounds,owing to poor blood perfusion.Platelet-rich plasma(PRP)has attracted much attention as a means to improve wound healing,because it contains high growth factor concentrations.However,the burst-like release of PRP growth factors results in a short halflife of these therapeutic proteins,thus greatly limiting the therapeutic effect.In this study,we prepared PRP from human umbilical cord blood and developed an in situ photocrosslinkable PRP hydrogel glue(HNPRP)by adding a photoresponsive hyaluronic acid(HA-NB)into PRP.The HNPRP hydrogel allowed for controlled release of plateletderived growth factor-BB(PDGF-BB)and transforming growth factor-β(TGF-β)for up to 28 days.In vitro cell culture showed that HNPRP promoted migration of fibroblasts and keratinocytes as well as PRP and did not reveal the advantages of HNPRP.However,in a diabetic rat skin wound model,HNPRP treatment promoted faster wound closure.Furthermore,the HNPRP group,compared with the control,PRP and hydrogel only groups,showed significantly greater re-epithelialization and numbers of both newly formed and mature blood vessels.The HNPRP group also displayed higher collagen formation than did the control group.In conclusion,HNPRP enhances angiogenesis and skin regeneration and consequently achieves faster wound healing,thus extending its potential for clinical applications to treat diabetic skin wounds.
基金This work was supported by a grant from theNational Natural Science Foundation of China(No.30371481)the Natural Science Founda-tion of Shanghai(No.06ZR14053)theKey Project of the Shanghai Health Bureau(No.2005ZD002).
文摘OBJECTIVE To study the gene expression profiles of human endometrial cancers at various differentia0ted grade levels and to identify the genes related to differentiation of the endometrial cancers. METHODS cDNA microarray technology was used to analyze the differentially-expressed genes among different differentiated grades of 32 cases of endometrial cancer. Hierarchical cluster analysis （HCA） for the gene expression profiles of the cases was employed. RESULTS The tissue samples were grouped based on the various differentiated tumor grades with 33 differentiation-related genes identified out （P〈0.001）. Based on the results from the HCA, the conformity rate was 91% among the 33 differentially-expressed genes, and the analysis of pathological classification.CONCLUSION Genes related to the differentiation of endometrial cancer can be identified by using gene chips to analyze the expression profiles of endometrial cancers at various differentiated grades; HCA of the gene expression profiles can be helpful for distinguishing high-risk endometrial cancers before surgery.
基金Supported by Activity Plan of Scientific Research and Entrepreneurship for Beijing College Students(NO.S201410022035)
文摘There is a close relationship between crassulacean acid metabolism and drought tolerance,and a great number of landscape plants which consume less water are necessary to build economic garden.In order to provide the basis for selecting drought-tolerant landscape plants,five species of plants were employed,including Dendrobium chrysotoxum,D.nobile,D.primulinum,Kalanchoblossfeldiana and K.daigremontiana.Exposed to different intensities of light,various samples were collected.The slices were prepared via different techniques.Stomatal movements and stomatal complex structures were observed by scanning electronic microscope and confocal laser scanning microscope.The results indicated that the slices made rapidly from fresh leaves were conductive to inspecting actual stomatal movements and stomatal complex structures as soon as possible.It was found that the stomatal movement of K.daigremontiana,K.blossfeldiana and D.primulinum displayed typical characteristics of crassulacean acid metabolism,while that of D.chrysotoxum and D.nobile did not exhibited obvious characteristics of crassulacean acid metabolism.
基金supported in part by the NARI Group Corporation Science and Technology project“Research on Coordinated Development of Carbon Emission Reduction and Carbon Sink Enhancement”。
文摘The nuclear event risk(NER)is an important and disputed factor that should be reasonably considered when planning the pathway of nuclear power development(NPD)to assess the benefits and risks of developing nuclear power more objectively.This paper aims to explore the impact of nuclear events on NPD pathway planning.The influence of nuclear events is quantified as a monetary risk component,and an optimization model that incorporates the NER in the objective function is proposed.To optimize the pathway of NPD in the lowcarbon transition course of power supply structure evolution,a simulation model is built to deduce alternative NPD pathways and corresponding power supply evolution scenarios under the constraint of an exogenously assigned carbon emission pathway(CEP);moreover,a method is proposed to describe the CEP by superimposing the maximum carbon emission space and each carbon emission reduction(CER)component,and various CER components are clustered considering the emission reduction characteristics and resource endowments of different power generation technologies.A case study is conducted to explore the impact of NER and its risk valuation uncertainty on NPD pathway planning.The method presented in this paper allows the impact of nuclear events on NPD pathway planning to be quantified and improves the level of coordinated optimization of benefits and risks.
