AIM: To investigate the effects of emodin on the treatment of non-alcoholic fatty liver in rats induced by high caloric laboratory chaw. METHODS: Non-alcoholic fatty liver model was successfully established by feeding...AIM: To investigate the effects of emodin on the treatment of non-alcoholic fatty liver in rats induced by high caloric laboratory chaw. METHODS: Non-alcoholic fatty liver model was successfully established by feeding with high caloric laboratory chaw for 12 wk. Then the model rats were randomly divided into 3 groups, namely model control group, emodin group and dietary treatment group. The rats in emodin group were given emodin at dose of 40 mg/(kg·d) while animals in other groups were given distilled water of the same volume. The rats in model control group were fed with high caloric laboratory chaw while animals in other groups were fed with normal diet. Four weeks later, liver index (liver/body weight ratio), serum activities of liver-associated enzymes, blood lipid, fasting blood glucose, fasting plasma insulin, HOMA insulin resistance index (HOMA-IR), hepatic triglyceride content and histology features of all groups were assayed. The expression of hepatic peroxisomal proliferator activated receptor (PPAR) gamma was determined by RT-PCR. RESULTS: The body weight, liver index, serum activities of alanine aminotransferase (ALT), blood lipid, hepatic triglyceride content of model control group were significantly elevated, with moderate to severe hepatocyte steatosis. The expression of hepatic PPAR gamma mRNA was obviously reduced in model control group. Compared with model control group, the body weight, liver index, serum activities of ALT, blood lipids and hepatic triglyceride of emodin group significantly decreased and hepatic histology display was also greatly improved. Meanwhile, the expression of hepatic PPAR gamma mRNA was elevated. However, high serum activities of ALT and hyperlipidemia were persisted in dietary treatment group although liver index was decreased and liver histology was somewhat improved. CONCLUSION: It is suggested that emodin might be effective in the treatment of non-alcoholic fatty liver in rats. Its therapeutic mechanism could be associated with increasing the expression of hepati展开更多
Hemiballism-hemichorea(HB-HC)is commonly used to describe the basal ganglion dysfunction in non-ketotic hyperglycemic elderly patients.Here we report two elderly female patients with acute onset of involuntary movemen...Hemiballism-hemichorea(HB-HC)is commonly used to describe the basal ganglion dysfunction in non-ketotic hyperglycemic elderly patients.Here we report two elderly female patients with acute onset of involuntary movements induced by hyperglycemia with positive urine ketones.We described the computed tomography and magnetic resonance imaging findings in these two patients,which is similar to that of non-ketotic hyperglycemic HB-HC patients.FDG-PET was performed and the glucose metabolism in the corresponding lesion in these two patients was contradictory with each other.We tried to clarify the underlying mechanisms of HB-HC and explain the contradictory neuroradiological findings in FDG-PET as being performed at different clinical stages.展开更多
Haploidentical stem cell transplantation(haplo-SCT)achieves superior or at least comparable clinical outcomes to HLA-matched sibling donor transplantation(MSDT)in treating hematological malignancies.To define the unde...Haploidentical stem cell transplantation(haplo-SCT)achieves superior or at least comparable clinical outcomes to HLA-matched sibling donor transplantation(MSDT)in treating hematological malignancies.To define the underlying regulatory dynamics,we analyzed time courses of leukemia burden and immune abundance of haplo-SCT or MSDT from multiple dimension.First,we employed two nonirradiated leukemia mouse models which carried human AML-ETO or MLL-AF9 fusion gene to establish haplo-identical and major histocompatibility(MHC)-matched transplantation models and investigated the immune cell dynamic response during leukemia development in vivo.We found that haplo-matching the MHCs of leukemia cells with recipient mouse T cells prolonged leukemic mice survival and reduced leukemia burden.The stronger graft-versus-leukemia activity in haplo-SCT group mainly induced by decreased apoptosis and increased cytotoxic cytokine secretion including tumor necrosis factor–α,interferon-γ,pore-forming proteins and CD107a secreted by T cells or natural killer cells.Furthermore,we conducted a prospective clinical trial which enrolled 135 patients with t(8;21)acute myeloid leukemia that displayed minimal residual disease before transplantation and underwent either haplo-SCT or MSDT.The results showed that the haplo-SCT slowed the kinetics of the leukemia burden in vivo and reduced the cumulative incidence of relapse compared with MSDT.Ex vivo experiments showed that,1 year after transplantation,cytotoxic T lymphocytes from the haplo-SCT group had higher cytotoxicity than those from the MSDT group during the same period.Our results unraveled the role of immune cells in superior antileukemia effects of haplo-SCT compared with MSDT.展开更多
AIM: Codon 72 exon 4 polymorphism (Arg72Pro) of the p53 gene has been implicated in cancer risk. Our objective was to investigate the possible association between p53Arg72Pro polymorphism and susceptibility to hepatoc...AIM: Codon 72 exon 4 polymorphism (Arg72Pro) of the p53 gene has been implicated in cancer risk. Our objective was to investigate the possible association between p53Arg72Pro polymorphism and susceptibility to hepatocellular carcinoma (HCC) among Chinese population.METHODS: The p53 Arg72Pro genotypes were determined by PCR-based restriction fragment length polymorphism (RFLP) analysis in 507 HCC cases and 541 controls. Odds ratios (ORs) for HCC and 95% confidence intervals (CIs)from unconditional logistic regression models were used to evaluate relative risks. Potential risk factors were included in the logistic regression models as covariates in the multivariate analyses on genotype and HCC.RESULTS: The frequencies for Pro and Arg alleles were 44.5%, 55.5% in HCC cases, and 40.3% and 59.7% in controls, respectively. The Pro allele was significantly associated with the presence of HCC (P = 0.05) and had a higher risk for HCC (OR = 1.19, 95% CI 1.00-1.41) as compared with the Arg allele. After adjusted for potential risk factors, Arg/Pro heterozygotes had an 1.21-fold increased risk (95% CI 0.82-1.78, P = 0.34) of HCC compared with Arg homozygotes, whereas the risk for Pro homozygotes was 1.79 (95% CI 1.06-3.01, P = 0.03) times higher than that for Arg homozygotes. Pro-allele carriers had a higher relative risk of HCC than the Arg-only carriers (adjusted OR = 1.33, 95% CI 0.92-1.92, P = 0.13), although the difference was not statistically significant.CONCLUSION: Homozygosity for Pro of p53 Arg72Pro is potentially one of the genetic risk factors for HCC in Chinese population. The p53 Arg72Pro polymorphism may be used as a stratification marker in screening individuals at a high risk of HCC.展开更多
Polyolefins(POs,i.e.,polyethylenes,ethylene/α-olefin copolymers,and polypropylenes)are the most ubiquitous synthetic macromolecular materials in modern life.Their widespread use and low recovery rate after extensive ...Polyolefins(POs,i.e.,polyethylenes,ethylene/α-olefin copolymers,and polypropylenes)are the most ubiquitous synthetic macromolecular materials in modern life.Their widespread use and low recovery rate after extensive usage have caused significant resource waste and environmental concerns.Chemical recycling of POs provides an efficient approach to unravelling the polymer chain to various chemicals.However,conventional chemical recycling methods,including pyrolysis,hydrocracking,and oxidation,require high-energy input(typically>500℃)and/or the use of environmentally unfriendly chemicals,leading to complex product distribution.In this minireview,based on recent representative works,we summarize and highlight catalytic strategies addressing these issues in PO recycling from two perspectives:(1)employing advanced catalysts or technique designs to overcome the challenges in conventional chemical deconstruction approaches;and(2)developing novel tandem/cascade catalytic systems for highly selective PO upcycling under relatively mild conditions.We hope that this minireview will help researchers better understand the state of the art of PO chemical recycling and inspire more innovative and efficient ideas for this fast-developing field.展开更多
Engineering of defects in semiconductors provides an effective protocol for improving photocatalytic N_(2) conversion efficiency.This review focuses on the state-of-the-art progress in defect engineering of photocatal...Engineering of defects in semiconductors provides an effective protocol for improving photocatalytic N_(2) conversion efficiency.This review focuses on the state-of-the-art progress in defect engineering of photocatalysts for the N_(2) reduction toward ammonia.The basic principles and mechanisms of thermal catalyzed and photon-induced N_(2) reduction are first concisely recapped,including relevant properties of the N_(2) molecule,reaction pathways,and NH3 quantification methods.Subsequently,defect classification,synthesis strategies,and identification techniques are compendiously summarized.Advances of in situ characterization techniques for monitoring defect state during the N_(2) reduction process are also described.Especially,various surface defect strategies and their critical roles in improving the N_(2) photoreduction performance are highlighted,including surface vacancies(i.e.,anionic vacancies and cationic vacancies),heteroatom doping(i.e.,metal element doping and nonmetal element doping),and atomically defined surface sites.Finally,future opportunities and challenges as well as perspectives on further development of defect-engineered photocatalysts for the nitrogen reduction to ammonia are presented.It is expected that this review can provide a profound guidance for more specialized design of defect-engineered catalysts with high activity and stability for nitrogen photochemical fixation.展开更多
Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear memory.Cylindromatosis(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-...Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear memory.Cylindromatosis(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-B pathway.CYLD is well studied in non-neuronal cells,yet underinvestigated in the brain,where it is highly expressed.Emerging studies have shown involvement of CYLD in the remodeling of glutamatergic synapses,neuroinflammation,fear memory,and anxiety-and autism-like behaviors.However,the precise role of CYLD in glutamatergic neurons is largely unknown.Here,we first proposed involvement of CYLD in cued fear expression.We next constructed transgenic model mice with specific deletion of Cyld from glutamatergic neurons.Our results show that glutamatergic CYLD deficiency exaggerated the expression of cued fear in only male mice.Further,loss of CYLD in glutamatergic neurons resulted in enhanced neuronal activation,impaired excitatory synaptic transmission,and altered levels of glutamate receptors accompanied by over-activation of microglia in the basolateral amygdala of male mice.Altogether,our study suggests a critical role of glutamatergic CYLD in maintaining normal neuronal,synaptic,and microglial activation.This may contribute,at least in part,to cued fear expression.展开更多
A new experiment-library least-squares(experiment-LLs) method used in the neutron inelastic-scattering and thermal-capture analysis(NITA) technique for on-line coal analysis was developed,which has significantly decre...A new experiment-library least-squares(experiment-LLs) method used in the neutron inelastic-scattering and thermal-capture analysis(NITA) technique for on-line coal analysis was developed,which has significantly decreased the non-linear radiation effects.In this method,sixty samples with preset elemental contents were made,from whose experimental spectra twenty single-element spectrum libraries corresponding to twenty kinds of coal were built using the least-squares method.The spectrum of the unknown sample was analyzed based on these twenty libraries to estimate its element contents.With the initial estimated result,the procedure of developing library and analysis was iterated to build a new library with the closest element contents to the unknown sample.Hence the experiment-LLs method can reduce non-linear radiation effects.The experiment-LLs method was performed on an improved coal analysis system which was equipped with a long-life 14 MeV pulsed-neutron generator,a bulk BGO detector with a temperature controller,a moisture meter and coal-smoothing device.The precisions of this system for ash content,water content,volatile content and calorific value have reached 1.0wt%,0.5wt%,1.0wt%,350 kJ/kg,respectively.展开更多
Cu/ZrO2 catalysts for methanol synthesis from CO2/H2 were respectively prepared by deposition coprecipitation （DP） and solid state reaction （SR） methods. There is an intimate interaction between copper and zirconi...Cu/ZrO2 catalysts for methanol synthesis from CO2/H2 were respectively prepared by deposition coprecipitation （DP） and solid state reaction （SR） methods. There is an intimate interaction between copper and zirconia, which strongly affects the reduction property and catalytic performance of the catalysts. The stronger the interaction, the lower the reduction temperature and the better the performance of the catalysts. Surface area, pore structure and crystal structure of the catalysts are mainly controlled by preparation methods and alkalinity of synthesis system. The conversion of CO2 and selectivity of methanol are higher for DP catalysts than for SP catalysts.展开更多
To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were de...To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were deposited onto Si(100) and cemented carbide substrates using TiSi targets with different Si content by cathodic arc ion plating. The influences of Si on the microstructure and mechanical properties were studied. Nano-amorphous composite structure appeared in the Ti1-xSixN coatings when Si content in TiSi target was higher than 5 at%. However, further increase of Si content in TiSi target exhibited a negligible effect on the microstructure of Ti1-xSixN coatings. Hardness and deformation resistance were correlated to the content of Si in TiSi targets. Maximum hardness was obtained as the Si content in target increased up to 20 at%. Friction coefficient and wear rate significantly decreased with addition of Si in TiN coating, and then dually increased with the increase of Si content in targets.展开更多
Photocatalytic O_(2)activation to generate reactive oxygen species is crucially important for purifying organic pollutants,yet remains a challenge due to poor adsorption of O_(2)and low efficiency of electron transfer...Photocatalytic O_(2)activation to generate reactive oxygen species is crucially important for purifying organic pollutants,yet remains a challenge due to poor adsorption of O_(2)and low efficiency of electron transfer.Herein,we demonstrate that ultrafine MoO_(x)clusters anchored on graphitic carbon nitride(g-C_(3)N_(4))with dual nitrogen/oxygen defects promote the photocatalytic activation of O_(2)to generate·O_(2)−for the degradation of tetracycline hydrochloride(TCH).A range of characterization techniques and density functional theory(DFT)calculations reveal that the introduction of the nitrogen/oxygen dual defects and MoO_(x)clusters enhances the O_(2)adsorption energy from−2.77 to−2.94 eV.We find that MoO_(x)clusters with oxygen vacancies(Ov)and surface Ov-mediated Moδ+(3≥δ≥2)possess unpaired localized electrons,which act as electron capture centers to transfer electrons to the MoO_(x)clusters.These electrons can then transfer to the surface adsorbed O_(2),thus promoting the photocatalytic conversion of O_(2)to·O_(2)−and,simultaneously,realizing the efficient separation of photogenerated electron–hole pairs.Our fully-optimized MoO_(x)/g-C_(3)N_(4)catalyst with dual nitrogen/oxygen defects manifests outstanding photoactivities,achieving 79%degradation efficiency toward TCH within 120 min under visible light irradiation,representing nearly 7 times higher activity than pristine g-C_(3)N_(4).Finally,based on the results of liquid chromatograph mass spectrometry and DFT calculations,the possible photocatalytic degradation pathways of TCH were proposed.展开更多
Gas-filled internal crack might appear in thermoset materials like epoxy resin during the equipment manufacturing,which would become a vulnerable local region to initiate the electrical tree,thus prone to cause insula...Gas-filled internal crack might appear in thermoset materials like epoxy resin during the equipment manufacturing,which would become a vulnerable local region to initiate the electrical tree,thus prone to cause insulation failure.The withstand voltage test was carried on epoxy samples with artificial cracks based on a rod-plane electrode arrange-ment.Simultaneously,surface state variation and tree evolution with crack were observed by an optical microscope in conjunction with a charge-coupled device camera.The changes in morphology and chemical status of the crack surface were characterized by scanning electron microscopy,laser Raman spectrometer and energy dispersive spec-trometer,respectively.It was found that the erosion and tree started from the borderline of crack under a relatively low electric field strength;however,the area near the electrode had relatively little damage.The breaking of epoxy molecular chains coarsens the crack surface and further forms deep channels on a micro-level,which is the forerunner of the electrical tree inception.Based on these,the initiation mechanisms of the crack-induced electrical tree and the reasons for the erosion near the borderline have been revealed.This study provides a train thought for the polymer degradation opening up into the initial tree channel during tree evolution processes.展开更多
In Australia,the proportion of forest area that burns in a typical fire season is less than for other vegetation types.However,the 2019-2020 austral spring-summer was an exception,with over four times the previous max...In Australia,the proportion of forest area that burns in a typical fire season is less than for other vegetation types.However,the 2019-2020 austral spring-summer was an exception,with over four times the previous maximum area burnt in southeast Australian temperate forests.Temperate forest fires have extensive socio-economic,human health,greenhouse gas emissions,and biodiversity impacts due to high fire intensities.A robust model that identifies driving factors of forest fires and relates impact thresholds to fire activity at regional scales would help land managers and fire-fighting agencies prepare for potentially hazardous fire in Australia.Here,we developed a machine-learning diagnostic model to quantify nonlinear relationships between monthly burnt area and biophysical factors in southeast Australian forests for 2001-2020 on a 0.25°grid based on several biophysical parameters,notably fire weather and vegetation productivity.Our model explained over 80%of the variation in the burnt area.We identified that burnt area dynamics in southeast Australian forest were primarily controlled by extreme fire weather,which mainly linked to fluctuations in the Southern Annular Mode(SAM)and Indian Ocean Dipole(IOD),with a relatively smaller contribution from the central Pacific El Niño Southern Oscillation(ENSO).Our fire diagnostic model and the non-linear relationships between burnt area and environmental covariates can provide useful guidance to decision-makers who manage preparations for an upcoming fire season,and model developers working on improved early warning systems for forest fires.展开更多
Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes w...Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes was designed to generate Dean flow,which was used to enhance the liquid-liquid micromixing performance.The Villermaux-Dushman probe reaction was employed to characterize the micromixing performance in different curved capillary microreactors.The effects of experiment parameters such as liquid flow rate,inner diameter,tube length,and curve diameter on micromixing performance were systematically investigated.Under the optimal conditions,the minimum value of the segmentation factor XS was 0.008.It was worth noting that at the low Reynolds number(Re<30),the change of curved shape on the capillary microreactor can significantly improve the micromixing performance with XS reduced by 37.5%.Further,the correlations of segment index XS with dimensionless factor such as Reynolds number or Dean number were developed,which can be used to predict the liquid-liquid micromixing performance in capillary microreactors.展开更多
The research of rolling mill vibration theory has always been a scientific problem in the field of rolling forming,which is very important to the quality of sheet metal and the stable operation of equipment.The essenc...The research of rolling mill vibration theory has always been a scientific problem in the field of rolling forming,which is very important to the quality of sheet metal and the stable operation of equipment.The essence of rolling mill vibration is the transfer of energy,which is generated from inside and outside.Based on particle damping technology,a dynamic vibration absorber(DVA)is proposed to control the vertical vibration of roll in the rolling process from the point of energy transfer and dissipation.A nonlinear vibration equation for the DVA-roller system is solved by the incremental harmonic balance method.Based on the obtained solutions,the effects of the basic parameters of the DVA on the properties of vibration transmission are investigated by using the power flow method,which provides theoretical guidance for the selection of the basic parameters of the DVA.Furthermore,the influence of the parameters of the particles on the overall dissipation of energy of the particle group is analyzed in a more systematic way,which provides a reference for the selection of the material and diameter and other parameters of the particles in the practical application of the DVA.The effect of particle parameters on roll amplitude inhibition is studied by experiments.The experimental results agree with the theoretical analysis,which proves the correctness of the theoretical analysis and the feasibility of the particle damping absorber.This research proposes a particle damping absorber to absorb and dissipate the energy transfer in rolling process,which provides a new idea for nonlinear dynamic analysis and stability control of rolling mills,and has important guiding significance for practical production.展开更多
Nanoscale hierarchically porous metal-organic frameworks(NH-MOFs)synergistically combine the advantages of nanoscale MOFs and hierarchically porous MOFs,resulting in remarkable characteristics such as increased specif...Nanoscale hierarchically porous metal-organic frameworks(NH-MOFs)synergistically combine the advantages of nanoscale MOFs and hierarchically porous MOFs,resulting in remarkable characteristics such as increased specific surface area,greater porosity,and enhanced exposure of active sites.Herein,nanoscale hierarchically porous UIO-66(UIO-66_X)was synthesized using a defect-induced strategy that employed ethylene diamine tetraacetic acid(EDTA)as a modulator.The introduced EDTA occupies the coordination sites of organic ligands,promoting the formation and growth of UIO-66 crystal nuclei and inducing defects during synthesis.The as-synthesized UIO-66_X crystals exhibit a uniform distribution with an average size of approximately 100 nm.In addition,the total pore volume attains a remarkable value of 0.95 cm^(3)g^(-1),with mesopores constituting 36.8% of the structure.Furthermore,the porosities of UIO-66_X can be easily tuned by controlling the molar ratio of EDTA/Zr^(4+).In addition,the as-synthesized UIO-66_X exhibits excellent adsorption capacities for n-hexane(344 mg g^(-1))and pxylene(218 mg g^(-1)),which are 44.5% and 27.5% higher than those of conventional UIO-66,respectively.Finally,the adsorption behavior of n-hexane and p-xylene molecules in UIO-66_X was investigated using density functional theory simulations.展开更多
Plague has caused the death of hundreds of millions of people throughout the human history.Today this disease is again re-emerging and hence is again becoming an increasing threat to human health in several parts of t...Plague has caused the death of hundreds of millions of people throughout the human history.Today this disease is again re-emerging and hence is again becoming an increasing threat to human health in several parts of the world.However,impacts of global climate variation(e.g.El Nino and Southern Oscillation[ENSO])and global warming on plagues are largely unknown.Using cross-spectral analysis and cross-wavelet analysis,we have analyzed the relationship between increase rate of human plague in China during 1871–2003 and the following climate factors(as measured by the Southern Oscillation Index[SOI],Sea Surface Temperature of east Pacific equator[SST]and air Temperature of the Northern Hemisphere[NHT]).We found in the frequency domain that increase rate of human plague was closely associated with SOI and SST.Cross-spectral analysis reveals that significant coherencies between increase rate of human plague and ENSO were found over short periods(2–3 years),medium periods(6–7 years)and long periods(11–12 years,30–40 years).Cross-wavelet analysis reveals that increase rate of human plague oscillates in phase with SOI,but in anti-phase with SST over periods of 2–4 years and approximately 8 years(6–10 years).These results indicate that ENSO-driven climate variation may be important for occurrences of human plague in China.However,there is a need for a further analysis of the underlying mechanism between human plague in China and ENSO.展开更多
Wide-bandgap mixed-halide perovskite solar cells(WBG-PSCs)are promising top cells for efficient tandem photovoltaics to achieve high power conversion efficiency(PCE)at low cost.However,the open-circuit voltage(V_(OC))...Wide-bandgap mixed-halide perovskite solar cells(WBG-PSCs)are promising top cells for efficient tandem photovoltaics to achieve high power conversion efficiency(PCE)at low cost.However,the open-circuit voltage(V_(OC))of WBG-PSCs is still unsatisfactory as the V_(OC)-deficit is generally larger than 0.45 V.Herein,we report a buried interface engineering strategy that substantially improves the V_(OC)of WBG-PSCs by inserting amphiphilic molecular hole-selective materials featuring with a cyanovinyl phosphonic acid(CPA)anchoring group between the perovskite and substrate.The assembly and redistribution of CPA-based amphiphilic molecules at the perovskite-substrate buried interface not only promotes the growth of a low-defect crystalline perovskite thin film,but also suppresses the photo-induced halide phase separation.The energy level alignment between wide-bandgap perovskite and the hole-selective layer is further improved by modulating the substituents on the triphenylamine donor moiety(methoxyls for MPA-CPA,methyls for Me PA-CPA,and bare TPA-CPA).Using a 1.68 e V bandgap perovskite,the Me PA-CPA-based devices achieved an unprecedentedly high V_(OC)of 1.29 V and PCE of 22.3%under standard AM 1.5 sunlight.The V_(OC)-deficit(<0.40 V)is the lowest value reported for WBG-PSCs.This work not only provides an effective approach to decreasing the V_(OC)-deficit of WBG-PSCs,but also confirms the importance of energy level alignment at the charge-selective layers in PSCs.展开更多
In this study,a sulfur–phosphorus co-doped nanocarbon(SPC)catalyst was syn-thesized using a straightforward one-step colloidal carbonization method and demonstrated high performance in the metal-free direct oxidation...In this study,a sulfur–phosphorus co-doped nanocarbon(SPC)catalyst was syn-thesized using a straightforward one-step colloidal carbonization method and demonstrated high performance in the metal-free direct oxidation of alcohols to aldehydes.This metal-free SPC catalyst showed exceptional efficiency,achiev-ing a conversion rate of 90%for benzyl alcohol and a selectivity of 94%toward benzaldehyde within only 1 h at 130◦C.Moreover,it displays exceptional cycle stability and a high turnover frequency(17.1×10-3 mol g-1 h-1).Theoretical analysis suggested that the catalyst’s superior performance is attributed to the presence of unsaturated edge defects and S-P-moieties,which increase the density of states at the Fermi level,lower the band gap energy,and promote electron localization.Additionally,the doping introduces cooperative co-active S-P-C sites,facilitating a synergistic multisite catalytic effect that lowers the energy barriers.These findings represent a significant advancement in the field of metal-free direct alcohol oxidation.展开更多
基金Supported by Key Research Projects of Hubei Province, No.2002AA302B13
文摘AIM: To investigate the effects of emodin on the treatment of non-alcoholic fatty liver in rats induced by high caloric laboratory chaw. METHODS: Non-alcoholic fatty liver model was successfully established by feeding with high caloric laboratory chaw for 12 wk. Then the model rats were randomly divided into 3 groups, namely model control group, emodin group and dietary treatment group. The rats in emodin group were given emodin at dose of 40 mg/(kg·d) while animals in other groups were given distilled water of the same volume. The rats in model control group were fed with high caloric laboratory chaw while animals in other groups were fed with normal diet. Four weeks later, liver index (liver/body weight ratio), serum activities of liver-associated enzymes, blood lipid, fasting blood glucose, fasting plasma insulin, HOMA insulin resistance index (HOMA-IR), hepatic triglyceride content and histology features of all groups were assayed. The expression of hepatic peroxisomal proliferator activated receptor (PPAR) gamma was determined by RT-PCR. RESULTS: The body weight, liver index, serum activities of alanine aminotransferase (ALT), blood lipid, hepatic triglyceride content of model control group were significantly elevated, with moderate to severe hepatocyte steatosis. The expression of hepatic PPAR gamma mRNA was obviously reduced in model control group. Compared with model control group, the body weight, liver index, serum activities of ALT, blood lipids and hepatic triglyceride of emodin group significantly decreased and hepatic histology display was also greatly improved. Meanwhile, the expression of hepatic PPAR gamma mRNA was elevated. However, high serum activities of ALT and hyperlipidemia were persisted in dietary treatment group although liver index was decreased and liver histology was somewhat improved. CONCLUSION: It is suggested that emodin might be effective in the treatment of non-alcoholic fatty liver in rats. Its therapeutic mechanism could be associated with increasing the expression of hepati
文摘Hemiballism-hemichorea(HB-HC)is commonly used to describe the basal ganglion dysfunction in non-ketotic hyperglycemic elderly patients.Here we report two elderly female patients with acute onset of involuntary movements induced by hyperglycemia with positive urine ketones.We described the computed tomography and magnetic resonance imaging findings in these two patients,which is similar to that of non-ketotic hyperglycemic HB-HC patients.FDG-PET was performed and the glucose metabolism in the corresponding lesion in these two patients was contradictory with each other.We tried to clarify the underlying mechanisms of HB-HC and explain the contradictory neuroradiological findings in FDG-PET as being performed at different clinical stages.
基金supported by grants from the National Key Research and Development Program of China(2017YFA0104500)the Beijing Municipal Science and Technology Commission(Z181100009618032)+2 种基金the National Natural Science Foundation of China(Grant No.81621001,81530046,81770189,81670186,81870141 and 82070185)CAMS Innovation Fund for Medical Sciences(CIFMS)(grant number:2019-I2M-5-034)the Peking University Clinical Scientist Program(BMU2019LCKXJ003).
文摘Haploidentical stem cell transplantation(haplo-SCT)achieves superior or at least comparable clinical outcomes to HLA-matched sibling donor transplantation(MSDT)in treating hematological malignancies.To define the underlying regulatory dynamics,we analyzed time courses of leukemia burden and immune abundance of haplo-SCT or MSDT from multiple dimension.First,we employed two nonirradiated leukemia mouse models which carried human AML-ETO or MLL-AF9 fusion gene to establish haplo-identical and major histocompatibility(MHC)-matched transplantation models and investigated the immune cell dynamic response during leukemia development in vivo.We found that haplo-matching the MHCs of leukemia cells with recipient mouse T cells prolonged leukemic mice survival and reduced leukemia burden.The stronger graft-versus-leukemia activity in haplo-SCT group mainly induced by decreased apoptosis and increased cytotoxic cytokine secretion including tumor necrosis factor–α,interferon-γ,pore-forming proteins and CD107a secreted by T cells or natural killer cells.Furthermore,we conducted a prospective clinical trial which enrolled 135 patients with t(8;21)acute myeloid leukemia that displayed minimal residual disease before transplantation and underwent either haplo-SCT or MSDT.The results showed that the haplo-SCT slowed the kinetics of the leukemia burden in vivo and reduced the cumulative incidence of relapse compared with MSDT.Ex vivo experiments showed that,1 year after transplantation,cytotoxic T lymphocytes from the haplo-SCT group had higher cytotoxicity than those from the MSDT group during the same period.Our results unraveled the role of immune cells in superior antileukemia effects of haplo-SCT compared with MSDT.
基金Supported by the National Natural Science Foundation of China,No. 30370645, by the Hundred Leading Scientists Program of the Public Health Sector of Shanghai, No, 98BR007
文摘AIM: Codon 72 exon 4 polymorphism (Arg72Pro) of the p53 gene has been implicated in cancer risk. Our objective was to investigate the possible association between p53Arg72Pro polymorphism and susceptibility to hepatocellular carcinoma (HCC) among Chinese population.METHODS: The p53 Arg72Pro genotypes were determined by PCR-based restriction fragment length polymorphism (RFLP) analysis in 507 HCC cases and 541 controls. Odds ratios (ORs) for HCC and 95% confidence intervals (CIs)from unconditional logistic regression models were used to evaluate relative risks. Potential risk factors were included in the logistic regression models as covariates in the multivariate analyses on genotype and HCC.RESULTS: The frequencies for Pro and Arg alleles were 44.5%, 55.5% in HCC cases, and 40.3% and 59.7% in controls, respectively. The Pro allele was significantly associated with the presence of HCC (P = 0.05) and had a higher risk for HCC (OR = 1.19, 95% CI 1.00-1.41) as compared with the Arg allele. After adjusted for potential risk factors, Arg/Pro heterozygotes had an 1.21-fold increased risk (95% CI 0.82-1.78, P = 0.34) of HCC compared with Arg homozygotes, whereas the risk for Pro homozygotes was 1.79 (95% CI 1.06-3.01, P = 0.03) times higher than that for Arg homozygotes. Pro-allele carriers had a higher relative risk of HCC than the Arg-only carriers (adjusted OR = 1.33, 95% CI 0.92-1.92, P = 0.13), although the difference was not statistically significant.CONCLUSION: Homozygosity for Pro of p53 Arg72Pro is potentially one of the genetic risk factors for HCC in Chinese population. The p53 Arg72Pro polymorphism may be used as a stratification marker in screening individuals at a high risk of HCC.
基金support for this research by the National Key R&D Program of China(grant no.2021YFA1501700)the National Natural Science Foundation of China(grant nos.21825109,21821002,22072178,22293013,and 22272114)+1 种基金the CAS Youth Interdisciplinary Team(grant no.JCTD-2021-11)the Fundamental Research Funds from Sichuan University(grant no.2022SCUNL103)is gratefully acknowledged.
文摘Polyolefins(POs,i.e.,polyethylenes,ethylene/α-olefin copolymers,and polypropylenes)are the most ubiquitous synthetic macromolecular materials in modern life.Their widespread use and low recovery rate after extensive usage have caused significant resource waste and environmental concerns.Chemical recycling of POs provides an efficient approach to unravelling the polymer chain to various chemicals.However,conventional chemical recycling methods,including pyrolysis,hydrocracking,and oxidation,require high-energy input(typically>500℃)and/or the use of environmentally unfriendly chemicals,leading to complex product distribution.In this minireview,based on recent representative works,we summarize and highlight catalytic strategies addressing these issues in PO recycling from two perspectives:(1)employing advanced catalysts or technique designs to overcome the challenges in conventional chemical deconstruction approaches;and(2)developing novel tandem/cascade catalytic systems for highly selective PO upcycling under relatively mild conditions.We hope that this minireview will help researchers better understand the state of the art of PO chemical recycling and inspire more innovative and efficient ideas for this fast-developing field.
基金This work was supported by the National Natural Science Foundation of China(No.21972010)Beijing Natural Science Foundation(No.2192039)+1 种基金the Foundation of Key Laboratory of Low-Carbon Conversion Science&Engineering,Shanghai Advanced Research Institute,the Chinese Academy of Sciences(No.KLLCCSE-201901,SARI,CAS)Beijing University of Chemical Technology(XK180301,XK1804-2).
文摘Engineering of defects in semiconductors provides an effective protocol for improving photocatalytic N_(2) conversion efficiency.This review focuses on the state-of-the-art progress in defect engineering of photocatalysts for the N_(2) reduction toward ammonia.The basic principles and mechanisms of thermal catalyzed and photon-induced N_(2) reduction are first concisely recapped,including relevant properties of the N_(2) molecule,reaction pathways,and NH3 quantification methods.Subsequently,defect classification,synthesis strategies,and identification techniques are compendiously summarized.Advances of in situ characterization techniques for monitoring defect state during the N_(2) reduction process are also described.Especially,various surface defect strategies and their critical roles in improving the N_(2) photoreduction performance are highlighted,including surface vacancies(i.e.,anionic vacancies and cationic vacancies),heteroatom doping(i.e.,metal element doping and nonmetal element doping),and atomically defined surface sites.Finally,future opportunities and challenges as well as perspectives on further development of defect-engineered photocatalysts for the nitrogen reduction to ammonia are presented.It is expected that this review can provide a profound guidance for more specialized design of defect-engineered catalysts with high activity and stability for nitrogen photochemical fixation.
基金supported by the National Natural Science Foundation of China,Nos.32371065(to CL)and 32170950(to LY)the Natural Science Foundation of the Guangdong Province,No.2023A1515010899(to CL)the Science and Technology Projects in Guangzhou,Nos.2023A4J0578 and 2024A03J0180(to CW)。
文摘Neuronal activity,synaptic transmission,and molecular changes in the basolateral amygdala play critical roles in fear memory.Cylindromatosis(CYLD)is a deubiquitinase that negatively regulates the nuclear factor kappa-B pathway.CYLD is well studied in non-neuronal cells,yet underinvestigated in the brain,where it is highly expressed.Emerging studies have shown involvement of CYLD in the remodeling of glutamatergic synapses,neuroinflammation,fear memory,and anxiety-and autism-like behaviors.However,the precise role of CYLD in glutamatergic neurons is largely unknown.Here,we first proposed involvement of CYLD in cued fear expression.We next constructed transgenic model mice with specific deletion of Cyld from glutamatergic neurons.Our results show that glutamatergic CYLD deficiency exaggerated the expression of cued fear in only male mice.Further,loss of CYLD in glutamatergic neurons resulted in enhanced neuronal activation,impaired excitatory synaptic transmission,and altered levels of glutamate receptors accompanied by over-activation of microglia in the basolateral amygdala of male mice.Altogether,our study suggests a critical role of glutamatergic CYLD in maintaining normal neuronal,synaptic,and microglial activation.This may contribute,at least in part,to cued fear expression.
基金supported by the National Basic Research Program of China (Grant No. 2007CB815005)the National Natural Science Foundation of China (Grant No. 11075064)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No.20050183008)
文摘A new experiment-library least-squares(experiment-LLs) method used in the neutron inelastic-scattering and thermal-capture analysis(NITA) technique for on-line coal analysis was developed,which has significantly decreased the non-linear radiation effects.In this method,sixty samples with preset elemental contents were made,from whose experimental spectra twenty single-element spectrum libraries corresponding to twenty kinds of coal were built using the least-squares method.The spectrum of the unknown sample was analyzed based on these twenty libraries to estimate its element contents.With the initial estimated result,the procedure of developing library and analysis was iterated to build a new library with the closest element contents to the unknown sample.Hence the experiment-LLs method can reduce non-linear radiation effects.The experiment-LLs method was performed on an improved coal analysis system which was equipped with a long-life 14 MeV pulsed-neutron generator,a bulk BGO detector with a temperature controller,a moisture meter and coal-smoothing device.The precisions of this system for ash content,water content,volatile content and calorific value have reached 1.0wt%,0.5wt%,1.0wt%,350 kJ/kg,respectively.
文摘Cu/ZrO2 catalysts for methanol synthesis from CO2/H2 were respectively prepared by deposition coprecipitation （DP） and solid state reaction （SR） methods. There is an intimate interaction between copper and zirconia, which strongly affects the reduction property and catalytic performance of the catalysts. The stronger the interaction, the lower the reduction temperature and the better the performance of the catalysts. Surface area, pore structure and crystal structure of the catalysts are mainly controlled by preparation methods and alkalinity of synthesis system. The conversion of CO2 and selectivity of methanol are higher for DP catalysts than for SP catalysts.
基金Funded by the National Natural Science Foundation of China(U1832127)
文摘To investigate the evolution of microstructure and wear behavior of TiSiN coatings with the variation of Si in targets and lays the foundation for its controllable mass production, Ti1-xSixN composite coatings were deposited onto Si(100) and cemented carbide substrates using TiSi targets with different Si content by cathodic arc ion plating. The influences of Si on the microstructure and mechanical properties were studied. Nano-amorphous composite structure appeared in the Ti1-xSixN coatings when Si content in TiSi target was higher than 5 at%. However, further increase of Si content in TiSi target exhibited a negligible effect on the microstructure of Ti1-xSixN coatings. Hardness and deformation resistance were correlated to the content of Si in TiSi targets. Maximum hardness was obtained as the Si content in target increased up to 20 at%. Friction coefficient and wear rate significantly decreased with addition of Si in TiN coating, and then dually increased with the increase of Si content in targets.
基金supported by the National Natural Science Foundation of China(No.21972010)the National Key Research and Development Program of China(No.2022YFC2105900).
文摘Photocatalytic O_(2)activation to generate reactive oxygen species is crucially important for purifying organic pollutants,yet remains a challenge due to poor adsorption of O_(2)and low efficiency of electron transfer.Herein,we demonstrate that ultrafine MoO_(x)clusters anchored on graphitic carbon nitride(g-C_(3)N_(4))with dual nitrogen/oxygen defects promote the photocatalytic activation of O_(2)to generate·O_(2)−for the degradation of tetracycline hydrochloride(TCH).A range of characterization techniques and density functional theory(DFT)calculations reveal that the introduction of the nitrogen/oxygen dual defects and MoO_(x)clusters enhances the O_(2)adsorption energy from−2.77 to−2.94 eV.We find that MoO_(x)clusters with oxygen vacancies(Ov)and surface Ov-mediated Moδ+(3≥δ≥2)possess unpaired localized electrons,which act as electron capture centers to transfer electrons to the MoO_(x)clusters.These electrons can then transfer to the surface adsorbed O_(2),thus promoting the photocatalytic conversion of O_(2)to·O_(2)−and,simultaneously,realizing the efficient separation of photogenerated electron–hole pairs.Our fully-optimized MoO_(x)/g-C_(3)N_(4)catalyst with dual nitrogen/oxygen defects manifests outstanding photoactivities,achieving 79%degradation efficiency toward TCH within 120 min under visible light irradiation,representing nearly 7 times higher activity than pristine g-C_(3)N_(4).Finally,based on the results of liquid chromatograph mass spectrometry and DFT calculations,the possible photocatalytic degradation pathways of TCH were proposed.
基金the science and technology project of State Grid Corporation of China(SGLNDK00KJJS1900250)the Fundamental Research Funds for the Central Universities(xzy012019029).
文摘Gas-filled internal crack might appear in thermoset materials like epoxy resin during the equipment manufacturing,which would become a vulnerable local region to initiate the electrical tree,thus prone to cause insulation failure.The withstand voltage test was carried on epoxy samples with artificial cracks based on a rod-plane electrode arrange-ment.Simultaneously,surface state variation and tree evolution with crack were observed by an optical microscope in conjunction with a charge-coupled device camera.The changes in morphology and chemical status of the crack surface were characterized by scanning electron microscopy,laser Raman spectrometer and energy dispersive spec-trometer,respectively.It was found that the erosion and tree started from the borderline of crack under a relatively low electric field strength;however,the area near the electrode had relatively little damage.The breaking of epoxy molecular chains coarsens the crack surface and further forms deep channels on a micro-level,which is the forerunner of the electrical tree inception.Based on these,the initiation mechanisms of the crack-induced electrical tree and the reasons for the erosion near the borderline have been revealed.This study provides a train thought for the polymer degradation opening up into the initial tree channel during tree evolution processes.
基金supported by the National Natural Science Foundation of China(42088101 and 42030605)support from the research project:Towards an Operational Fire Early Warning System for Indonesia(TOFEWSI)+1 种基金The TOFEWSI project was funded from October 2017-October 2021 through the UK’s National Environment Research Council/Newton Fund on behalf of the UK Research&Innovation(NE/P014801/1)(UK Principal InvestigatorAllan Spessa)(https//tofewsi.github.io/)financial support from the Natural Science Foundation of Qinghai(2021-HZ-811)。
文摘In Australia,the proportion of forest area that burns in a typical fire season is less than for other vegetation types.However,the 2019-2020 austral spring-summer was an exception,with over four times the previous maximum area burnt in southeast Australian temperate forests.Temperate forest fires have extensive socio-economic,human health,greenhouse gas emissions,and biodiversity impacts due to high fire intensities.A robust model that identifies driving factors of forest fires and relates impact thresholds to fire activity at regional scales would help land managers and fire-fighting agencies prepare for potentially hazardous fire in Australia.Here,we developed a machine-learning diagnostic model to quantify nonlinear relationships between monthly burnt area and biophysical factors in southeast Australian forests for 2001-2020 on a 0.25°grid based on several biophysical parameters,notably fire weather and vegetation productivity.Our model explained over 80%of the variation in the burnt area.We identified that burnt area dynamics in southeast Australian forest were primarily controlled by extreme fire weather,which mainly linked to fluctuations in the Southern Annular Mode(SAM)and Indian Ocean Dipole(IOD),with a relatively smaller contribution from the central Pacific El Niño Southern Oscillation(ENSO).Our fire diagnostic model and the non-linear relationships between burnt area and environmental covariates can provide useful guidance to decision-makers who manage preparations for an upcoming fire season,and model developers working on improved early warning systems for forest fires.
基金supports of National Natural Science Foundation of China(22308057)Outstanding Talent Introduction Funds from Fuzhou University(0040-511175)Fuzhou University Testing Fund of precious apparatus(2023T003).
文摘Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes was designed to generate Dean flow,which was used to enhance the liquid-liquid micromixing performance.The Villermaux-Dushman probe reaction was employed to characterize the micromixing performance in different curved capillary microreactors.The effects of experiment parameters such as liquid flow rate,inner diameter,tube length,and curve diameter on micromixing performance were systematically investigated.Under the optimal conditions,the minimum value of the segmentation factor XS was 0.008.It was worth noting that at the low Reynolds number(Re<30),the change of curved shape on the capillary microreactor can significantly improve the micromixing performance with XS reduced by 37.5%.Further,the correlations of segment index XS with dimensionless factor such as Reynolds number or Dean number were developed,which can be used to predict the liquid-liquid micromixing performance in capillary microreactors.
基金Supported by National Natural Science Foundation of China(Grant No.52205404)National Key Research and Development Project(Grant No.2018YFA0707300)+2 种基金Fundamental Research Program of Shanxi Province(Grant Nos.202203021212293,202203021221054)Xinjiang Intelligent Equipment Research Institute Directed Commissioned Research Projects(Grant No.XJYJY2024012)Open Research Fund from the Hai’an&Taiyuan University of Technology Advanced Manufacturing and Intelligent Equipment Industrial Research Institute(Grant No.2023HA-TYUTKFYF004).
文摘The research of rolling mill vibration theory has always been a scientific problem in the field of rolling forming,which is very important to the quality of sheet metal and the stable operation of equipment.The essence of rolling mill vibration is the transfer of energy,which is generated from inside and outside.Based on particle damping technology,a dynamic vibration absorber(DVA)is proposed to control the vertical vibration of roll in the rolling process from the point of energy transfer and dissipation.A nonlinear vibration equation for the DVA-roller system is solved by the incremental harmonic balance method.Based on the obtained solutions,the effects of the basic parameters of the DVA on the properties of vibration transmission are investigated by using the power flow method,which provides theoretical guidance for the selection of the basic parameters of the DVA.Furthermore,the influence of the parameters of the particles on the overall dissipation of energy of the particle group is analyzed in a more systematic way,which provides a reference for the selection of the material and diameter and other parameters of the particles in the practical application of the DVA.The effect of particle parameters on roll amplitude inhibition is studied by experiments.The experimental results agree with the theoretical analysis,which proves the correctness of the theoretical analysis and the feasibility of the particle damping absorber.This research proposes a particle damping absorber to absorb and dissipate the energy transfer in rolling process,which provides a new idea for nonlinear dynamic analysis and stability control of rolling mills,and has important guiding significance for practical production.
基金financial support from the National Natural Science Foundation of China(22008032)the Guangdong Basic and Applied Basic Research Foundation(2023A1515011881,2020A1515110817,2022A1515011192,2023A1515010679,and 2020A1515110325)+1 种基金the Guangdong Provincial Key Laboratory of Intelligent Food Manufacturing(2022B1212010015,GPKLIFM-KF202206)the University Characteristic Innovation Foundation of Guangdong(2021KTSCX114 and 2022KTSCX122)。
文摘Nanoscale hierarchically porous metal-organic frameworks(NH-MOFs)synergistically combine the advantages of nanoscale MOFs and hierarchically porous MOFs,resulting in remarkable characteristics such as increased specific surface area,greater porosity,and enhanced exposure of active sites.Herein,nanoscale hierarchically porous UIO-66(UIO-66_X)was synthesized using a defect-induced strategy that employed ethylene diamine tetraacetic acid(EDTA)as a modulator.The introduced EDTA occupies the coordination sites of organic ligands,promoting the formation and growth of UIO-66 crystal nuclei and inducing defects during synthesis.The as-synthesized UIO-66_X crystals exhibit a uniform distribution with an average size of approximately 100 nm.In addition,the total pore volume attains a remarkable value of 0.95 cm^(3)g^(-1),with mesopores constituting 36.8% of the structure.Furthermore,the porosities of UIO-66_X can be easily tuned by controlling the molar ratio of EDTA/Zr^(4+).In addition,the as-synthesized UIO-66_X exhibits excellent adsorption capacities for n-hexane(344 mg g^(-1))and pxylene(218 mg g^(-1)),which are 44.5% and 27.5% higher than those of conventional UIO-66,respectively.Finally,the adsorption behavior of n-hexane and p-xylene molecules in UIO-66_X was investigated using density functional theory simulations.
基金an Albert Einstein Professorship to N.C.Stenseth,a cooperation grant(GJHZ0701-7)supported by the Chinese Academy of Sciences.
文摘Plague has caused the death of hundreds of millions of people throughout the human history.Today this disease is again re-emerging and hence is again becoming an increasing threat to human health in several parts of the world.However,impacts of global climate variation(e.g.El Nino and Southern Oscillation[ENSO])and global warming on plagues are largely unknown.Using cross-spectral analysis and cross-wavelet analysis,we have analyzed the relationship between increase rate of human plague in China during 1871–2003 and the following climate factors(as measured by the Southern Oscillation Index[SOI],Sea Surface Temperature of east Pacific equator[SST]and air Temperature of the Northern Hemisphere[NHT]).We found in the frequency domain that increase rate of human plague was closely associated with SOI and SST.Cross-spectral analysis reveals that significant coherencies between increase rate of human plague and ENSO were found over short periods(2–3 years),medium periods(6–7 years)and long periods(11–12 years,30–40 years).Cross-wavelet analysis reveals that increase rate of human plague oscillates in phase with SOI,but in anti-phase with SST over periods of 2–4 years and approximately 8 years(6–10 years).These results indicate that ENSO-driven climate variation may be important for occurrences of human plague in China.However,there is a need for a further analysis of the underlying mechanism between human plague in China and ENSO.
基金supported by the National Natural Science Foundation of China(22179037)Shanghai pilot program for Basic Research(22TQ1400100-1)+3 种基金Shanghai Municipal Science and Technology Major Project(2018SHZDZX03,21JC1401700)the Programmer of Introducing Talents of Discipline to Universities(B16017)the Fundamental Research Funds for the Central Universitiessupport from Royal Society of Chemistry(R23-0749928359)。
文摘Wide-bandgap mixed-halide perovskite solar cells(WBG-PSCs)are promising top cells for efficient tandem photovoltaics to achieve high power conversion efficiency(PCE)at low cost.However,the open-circuit voltage(V_(OC))of WBG-PSCs is still unsatisfactory as the V_(OC)-deficit is generally larger than 0.45 V.Herein,we report a buried interface engineering strategy that substantially improves the V_(OC)of WBG-PSCs by inserting amphiphilic molecular hole-selective materials featuring with a cyanovinyl phosphonic acid(CPA)anchoring group between the perovskite and substrate.The assembly and redistribution of CPA-based amphiphilic molecules at the perovskite-substrate buried interface not only promotes the growth of a low-defect crystalline perovskite thin film,but also suppresses the photo-induced halide phase separation.The energy level alignment between wide-bandgap perovskite and the hole-selective layer is further improved by modulating the substituents on the triphenylamine donor moiety(methoxyls for MPA-CPA,methyls for Me PA-CPA,and bare TPA-CPA).Using a 1.68 e V bandgap perovskite,the Me PA-CPA-based devices achieved an unprecedentedly high V_(OC)of 1.29 V and PCE of 22.3%under standard AM 1.5 sunlight.The V_(OC)-deficit(<0.40 V)is the lowest value reported for WBG-PSCs.This work not only provides an effective approach to decreasing the V_(OC)-deficit of WBG-PSCs,but also confirms the importance of energy level alignment at the charge-selective layers in PSCs.
基金National Natural Science Foundation of China,Grant/Award Numbers:31925028,32301541,22102019。
文摘In this study,a sulfur–phosphorus co-doped nanocarbon(SPC)catalyst was syn-thesized using a straightforward one-step colloidal carbonization method and demonstrated high performance in the metal-free direct oxidation of alcohols to aldehydes.This metal-free SPC catalyst showed exceptional efficiency,achiev-ing a conversion rate of 90%for benzyl alcohol and a selectivity of 94%toward benzaldehyde within only 1 h at 130◦C.Moreover,it displays exceptional cycle stability and a high turnover frequency(17.1×10-3 mol g-1 h-1).Theoretical analysis suggested that the catalyst’s superior performance is attributed to the presence of unsaturated edge defects and S-P-moieties,which increase the density of states at the Fermi level,lower the band gap energy,and promote electron localization.Additionally,the doping introduces cooperative co-active S-P-C sites,facilitating a synergistic multisite catalytic effect that lowers the energy barriers.These findings represent a significant advancement in the field of metal-free direct alcohol oxidation.
