Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are imp...Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are impeded by basic components aggregation and low stability.In this work,we fabricate single calcium atoms on graphene(denoted as Ca1/G)by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and stability.The precursor Ca(NO_(3))_(2)is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃results in the generation of Ca1/G with atomically dispersed Ca.Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination(Ca-C_(2)-N_(2))where N is in situ doped from Ca(NO_(3))_(2).The atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol.The turnover frequency value reaches 128.0 h^(-1)on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases(2.9-46.2 h^(-1)).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60%of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.展开更多
Background:Huoxue Tongjiang decoction(HXTJD)is an effective prescription for treating reflux esophagitis(RE).We investigated the effects of HXTJD on esophageal motility and mucosal inflammation in a rat RE model.Metho...Background:Huoxue Tongjiang decoction(HXTJD)is an effective prescription for treating reflux esophagitis(RE).We investigated the effects of HXTJD on esophageal motility and mucosal inflammation in a rat RE model.Methods:Chemical composition of HXTJD was analyzed by ultrahigh-performance liquid chromatography Q-Orbitrap mass spectrometry(MS).The change rates of mean contraction tension forces,mean amplitudes,and mean frequencies for the lower esophageal sphincter(LES)were recorded using the isolated tissue bath system,mechanical tension transducer,and PowerLab physiological recorder.After weighing the stomach,the phenol red labeling method was used to measure the gastric emptying rate.The LES ultrastructure was observed through transmission electron microscopy.Immunofluorescence and western blotting were used to detect the number of interstitial cells of Cajal(ICC)and the expression levels of c-kit protein,connexin43(Cx43),and stem cell factor(SCF).Flow cytometric analysis and enzyme-linked immunosorbent assay were conducted to detect the percentages of T helper 17(Th17)cells and regulatory T(Treg)cells and the serum concentrations of interleukin 6(IL-6),interleukin 17(IL-17),and interleukin 10(IL-10)in the rats.Results:We identified 28 chemical constituents in HXTJD.Regarding esophageal motility,we revealed that HXTJD increased the mean contraction tension forces,mean amplitudes,and mean frequency change rate of LES and the gastric emptying rate;decreased stomach weight;and improved the LES ultrastructure.Additionally,HXTJD increased the number of ICC-positive cells,and c-kit,Cx43,and SCF expression levels.Regarding esophageal inflammation,HXTJD significantly decreased the percentage of Th17 cells,and IL-6 and IL-17 concentrations,and increased the percentage of Treg cells and IL-10 concentration.Conclusion:HXTJD was found to be efficacious in the rat RE model.It may promote esophageal motility and alleviate the inflammatory response by activating the SCF/c-kit/ICC pathway and regulating the Th17/Treg cell balance.展开更多
The objective of this study was to investigate the mechanical characteristics of implant-abutment interface design in a dental implant system, using nonlinear finite element analysis (FEA) method. This finite elemen...The objective of this study was to investigate the mechanical characteristics of implant-abutment interface design in a dental implant system, using nonlinear finite element analysis (FEA) method. This finite element simulation study was applied on three commonly used commercial dental implant systems: model I, the reduced-diameter 3i implant system (West Palm Beach, FL, USA) with a hex and a 12-point double internal hexagonal connection; model II, the Semados implant system (Bego, Bremen, Germany) with combination of a conical (45° taper) and internal hexagonal connection; and model III, the Br,~nemark implant system (Nobel Biocare, Gothenburg, Sweden) with external hexagonal connection. In simulation, a force of 170 N with 45°oblique to the longitudinal axis of the implant was loaded to the top surface of the abutment. It has been found from the strength and stiffness analysis that the 3i implant system has the lowest maximum yon Mises stress, prirlcipal stress and displacement, while the Br^nemark implant system has the highest. It was concluded from our preliminary study using nonlinear FEA that the reduced-diameter 3i implant system with a hex and a 12-point double internal hexagonal connection had a better stress distribution, and produced a smaller displacement than the other two implant systems.展开更多
Hepatocellular carcinoma(HCC)is the fourth leading cause of cancer-related deaths worldwide.The prognosis of patients with HCC remains poor largely due to the late diagnosis and lack of effective treatments.Despite be...Hepatocellular carcinoma(HCC)is the fourth leading cause of cancer-related deaths worldwide.The prognosis of patients with HCC remains poor largely due to the late diagnosis and lack of effective treatments.Despite being widely used,alpha-fetoprotein serology and ultrasonography have limited diagnostic performance for early-stage HCC.The emergence of omics strategies has contributed to significant advances in the development of non-invasive biomarkers for the early diagnosis of HCC including proteins,metabolites,circulating tumor deoxyribonucleic acid,and circulating non-coding ribonucleic acid.Early diagnosis is beneficial to patients as it increases the proportion who can be treated with curative treatment,thus prolonging survival outcomes.Currently,multiple clinical trials involving locoregional,systemic therapies,and combinations of these modalities are changing therapeutic strategies for different stage HCC.Success in several preclinical trials that involve immunotherapeutic innovations has created the potential to complement and enforce other treatment strategies in the future.This review summarizes the most recent advances in noninvasive early molecular detection,current therapy strategies,and potential immunotherapeutic innovations of HCC.展开更多
In this work we report that after single-walled carbon nanotubes(SWNTs) are sheared with a pair of titanium scissors,the magnetization becomes larger than that of the corresponding pristine ones. The magnetization inc...In this work we report that after single-walled carbon nanotubes(SWNTs) are sheared with a pair of titanium scissors,the magnetization becomes larger than that of the corresponding pristine ones. The magnetization increases proportionally with the number of SWNTs with sheared ends, suggesting that there exist magnetic moments at the sheared ends of SWNTs.By using the coefficient of this linear relation, the average magnetic moment is estimated to be 41.5 ± 9.8 μB(Bohr magneton) per carbon atom in the edge state at temperature of 300.0 K, suggesting that ultrahigh magnetic fields can be produced. The dangling sigma and pi bonds of the carbon atoms at sheared ends play important roles in determining the unexpectedly high magnetic moments, which may have great potential applications.展开更多
Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (MOS-HEMTs) with post-etch surface treatment was studied in this paper. Diffusion-controlled interfa...Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (MOS-HEMTs) with post-etch surface treatment was studied in this paper. Diffusion-controlled interface oxidation treatment and wet etch process were adopted to improve the interface quality of MOS-HEMTs. With capacitance–voltage (C–V) measurement, the density of interface and border traps were calculated to be 1.13 × 10^12 cm^−2 and 6.35 × 10^12 cm^−2, effectively reduced by 27% and 14% compared to controlled devices, respectively. Furthermore, the state density distribution of border traps with large activation energy was analyzed using photo-assisted C–V measurement. It is found that irradiation of monochromatic light results in negative shift of C–V curves, which indicates the electron emission process from border traps. The experimental results reveals that the major border traps have an activation energy about 3.29 eV and the change of post-etch surface treatment process has little effect on this major activation energy.展开更多
BACKGROUND Neisseria mucosa is a gram negative diplococcus belonging to the genus Neisseria found commonly in the upper respiratory tract.It is typically a commensal organism when it is parasitic on oral and nasal muc...BACKGROUND Neisseria mucosa is a gram negative diplococcus belonging to the genus Neisseria found commonly in the upper respiratory tract.It is typically a commensal organism when it is parasitic on oral and nasal mucosa.To our knowledge,it does not cause disease in healthy individuals with normal immunity,but can be pathogenic in those with impaired immune function or change in bacterial colonization site.Neisseria mucosa has been reported to cause bacterial meningitis,conjunctivitis,pneumonia,endocarditis,peritonitis and urethritis.However,peritoneal dialysis-related peritonitis caused by Neisseria mucosa is extremely rare in clinical practice,which has not previously been reported in China.CASE SUMMARY A 55-year-old female presented to the nephrology clinic with upper abdominal pain without apparent cause,accompanied by nausea,vomiting and diarrhea for two days.The patient had a history of Stage 5 chronic kidney disease for five years,combined with renal hypertension and renal anemia,and was treated with peritoneal dialysis for renal replacement therapy.The patient was subsequently diagnosed with peritoneal dialysis-related peritonitis.Routine examination of peritoneal dialysis fluid showed abdominal infection,and the results of microbial culture of the peritoneal dialysis fluid confirmed Neisseria mucosa.Imi-penem/cilastatin 1.0 g q12h was added to peritoneal dialysis fluid for anti-infection treatment.After 24 d,the patient underwent upper extremity arteriovenous fistulation.One month later,the patient was discharged home in a clinically stable state.CONCLUSION Peritonitis caused by Neisseria mucosa is rare.Patients with home-based self-dialysis cannot guarantee good medical and health conditions,and require education on self-protection.展开更多
Objective To investigate the epidemiological features in children after the coronavirus disease 2019(COVID-19)pandemic.Methods This study collected throat swabs and serum samples from hospitalized pediatric patients o...Objective To investigate the epidemiological features in children after the coronavirus disease 2019(COVID-19)pandemic.Methods This study collected throat swabs and serum samples from hospitalized pediatric patients of Renmin Hospital of Wuhan University,Wuhan,Hubei province,China before and after the COVID-19 pandemic.Respiratory infected pathogens[adenovirus(ADV),influenza virus A/B(Flu A/B),parainfluenza virus 1/2/3(PIV1/2/3),respiratory syncytial virus(RSV),Mycoplasma pneumoniae(MP),and Chlamydia pneumoniae(CP)]were detected.The pathogens,age,and gender were used to analyze the epidemiological features in children after the COVID-19 pandemic.Results The pathogen detection rate was significantly higher in females than in males(P<0.05),and the infection of PIV1 and MP was mainly manifested.After the COVID-19 pandemic,PIV1,PIV3,RSV,and MP had statistically different detection rates among the age groups(P<0.05),and was mainly detected in patients aged 0–6 years,0–3 years,0–3 years,and 1–6 years,respectively.When comparing before the COVID-19 pandemic,the total detection rate of common respiratory pathogens was lower(P<0.05).Except for the increase in the detection rate of PIV1 and CP,the infection rate of other pathogens had almost decreased.Conclusion The prevention and control measures for the COVID-19 pandemic effectively changed the epidemiological features of common respiratory tract infectious diseases in pediatric children.展开更多
BACKGROUND Salmonella derby(S.derby)is a Gram-negative diplococcus that is common in the digestive tract.Infected patients generally experience symptoms such as fever and diarrhea.Mild cases are mostly self-healing ga...BACKGROUND Salmonella derby(S.derby)is a Gram-negative diplococcus that is common in the digestive tract.Infected patients generally experience symptoms such as fever and diarrhea.Mild cases are mostly self-healing gastroenteritis,and severe cases can cause fatal typhoid fever.Clinical cases are more common in children.The most common form of S.derby infection is self-healing gastroenteritis,in which,fever lasts for about 2 d and diarrhea for<7 d.S.derby can often cause bacterial conjunctivitis,pneumonia,endocarditis,peritonitis and urethritis.However,intracranial infections in infants caused by S.derby are rare in clinical practice and have not been reported before in China.CASE SUMMARY A 4-mo-old female infant had recurrent fever for 2 wk,with a maximum body temperature of around 39.4°C.Treatment for infectious fever in a local hospital was ineffective,and she was admitted to our hospital.Before admission,there was one sudden convulsion,characterized by unclear consciousness,limb twitching,gaze in both eyes,and slight cyanosis on the face.Cerebrospinal fluid(CSF)culture was positive for Gram-negative bacilli,which conformed to S.derby.After treatment with meropenem and ceftriaxone antibiotics,the patient was discharged home in a clinically stable state after 4 wk of treatment.CONCLUSION We reported a rare case of S.derby cultured in CSF.S.derby enters the CSF through the blood–brain barrier,causing purulent meningitis.If not treated timeously,it can lead to serious,life-threatening infection.展开更多
Backgroud:The electroacupuncture of auricular concha area(EA-ACR)proved to have a good regulatory effect on insomnia and the release of melatonin,which is most closely related to sleep.However,there is little research...Backgroud:The electroacupuncture of auricular concha area(EA-ACR)proved to have a good regulatory effect on insomnia and the release of melatonin,which is most closely related to sleep.However,there is little research to demonstrate the relationship between EA-ACR and melatonin.The objective of present study is to observe the effects of EA-ACR on the circadian rhythm of melatonin secretion in p-chlorophenylalanine(PCPA)-induced insomnia rats.Methods:The study divided 36 male Sprague-Dawley rats randomly into three groups:12 in blank group,12 in model group,and 12 in EA-ACR group.By using PCPA intraperitoneal injection for 2 days,insomnia model was established.EA-ACR group was treated for 28 days.We observed the effects of EA-ACR on the rats'behavioral changes,open-field test and weight during the experiment.After the experiment,the rat tail and heart blood were collected,and the melatonin was detected by enzyme-linked immunosorbent assay.Results:Compared with the blank group,28–30 hours after PCPA intraperitoneal injection,the circadian rhythm of sleep and the total sleep time of model rats decreased.Compared with the model group,electrical stimulation in the ear concha region could effectively reverse the behavioral changes of rats,and increase the trend of weight growth(P=0.010),the crossing score(P=0.014),vertical motion score(P=0.015)and the level of plasma melatonin secretion(P=0.020)with the trend showing a rhythmic pattern(0–60 minutes upward,60–120 minutes downward,120–150 minutes upward).Conclusion:EA-ACR can improve the quality of life(weight),ameliorate exploring irritable and anxiety behaviors in PCPA-induced insomnia rats.The underlying effects of EA-ACR may be excited on the circadian rhythm of melatonin secretion in PCPA-induced insomnia rats.展开更多
Background:Current surveillance strategies for hepatocellular carcinoma(HCC)among patients with non-alcoholic fatty liver disease(NAFLD)are insufficient.This study aimed to investigate the diagnostic perfor-mance of a...Background:Current surveillance strategies for hepatocellular carcinoma(HCC)among patients with non-alcoholic fatty liver disease(NAFLD)are insufficient.This study aimed to investigate the diagnostic perfor-mance of alpha-fetoprotein(AFP),protein induced by vitamin K absence or antagonist-Ⅱ(PIVKA-Ⅱ),lens culinaris agglutinin-reactive fraction of AFP(AFP-L3),and their combinations in HCC underlying NAFLD patients.Methods:Serologic AFP,AFP-L3,and PIVKA-Ⅱ levels in NAFLD patients with and without HCC were mea-sured.By receiver operating characteristic(ROC)analyses,the area under the curve(AUC),sensitivity,and specificity were obtained to evaluate the diagnostic accuracy of each biomarker and their combinations.Results:This study was conducted on 139 patients with NAFLD-HCC and 345 NAFLD controls.The eleva-tion of these three biomarkers was observed in patients with NAFLD-HCC compared to those in NAFLD controls(all P<0.001).When they were analyzed individually,PIVKA-Ⅱ showed the best performance in diagnosing any-stage HCC with an AUC of 0.869,followed by AFP(0.763;vs.PIVKA-Ⅱ,P<0.001)and AFP-L3(0.689;vs.PIVKA-II,P<0.001).When they were analyzed in combination,AFP+PIVKA-Ⅱ yielded the highest AUC(0.906),followed by AFP+PIVKA-II+AFP-L3(0.904;vs.AFP+PIVKA-Ⅱ,P=0.086),PIVKA-Ⅱ+AFP-L3(0.881;vs.AFP+PIVKA-II,P<0.001),and AFP+AFP-L3(0.759;vs.AFP+PIVKA-II,P<0.001).Similar findings were obtained in the subgroup with early-stage NAFLD-HCC,as well as the non-cirrhotic subgroup.Conclusions:These data validated the better diagnostic ability of PIVKA-II than AFP or AFP-L3 alone for diagnosing any-stage HCC among patients with NAFLD,and the combination of AFP+PIVKA-II signifi-cantly improved the diagnostic accuracy of NAFLD-HCC.展开更多
The Tian-ma Radio Telescope(TMRT) applies an Active Surface System(ASFS), which corrects for large-scale deformations due to gravity and thermal on the primary reflector. The centralized and automated management of th...The Tian-ma Radio Telescope(TMRT) applies an Active Surface System(ASFS), which corrects for large-scale deformations due to gravity and thermal on the primary reflector. The centralized and automated management of the ASFS using software has become a challenge, for which we have developed the TMRT Active Surface System Control Software(TASCS). This paper describes the design and implementation of TASCS for device control,status monitoring, human-computer interaction, and data management functionalities. TASCS adopts the opensource Tango Controls framework and distributes middleware technology to realize real-time automated adjustment of the primary reflector through remote centralized control of a large number of actuators. At present, it has been successfully deployed on the TMRT and has played an important role in Event Horizon Telescope observations.展开更多
This paper reports a low-damage interface treatment process for Al N/Ga N high electron mobility transistor(HEMT)and demonstrates the excellent power characteristics of radio-frequency(RF) enhancementmode(E-mode) Al N...This paper reports a low-damage interface treatment process for Al N/Ga N high electron mobility transistor(HEMT)and demonstrates the excellent power characteristics of radio-frequency(RF) enhancementmode(E-mode) Al N/Ga N HEMT. An RF E-mode device with 2.9-nm-thick Al N barrier layer fabricated by remote plasma oxidation(RPO) treatment at 300℃. The device with a gate length of 0.12-μm has a threshold voltage(Vth) of 0.5 V, a maximum saturation current of 1.16 A/mm, a high Ion/Ioff ratio of 1×108, and a 440-m S/mm peak transconductance. During continuous wave(CW) power testing, the device demonstrates that at 3.6 GHz, a power added efficiency is 61.9% and a power density is 1.38 W/mm, and at 30 GHz, a power added efficiency is 41.6% and a power density is 0.85 W/mm. Furthermore, the RPO treatment improves the mobility of RF E-mode Al N/Ga N HEMT. All results show that the RPO processing method has good applicability to scaling ultrathin barrier E-mode Al N/Ga N HEMT for 5G compliable frequency ranging from sub-6 GHz to Ka-band.展开更多
Objective:Systematically compared the effects of moxibustion and lipid-lowering drugs on hyperlipemia.Methods:Randomized controlled trials(RCTs)published before December 2018 were all aggregated,focusing on evaluation...Objective:Systematically compared the effects of moxibustion and lipid-lowering drugs on hyperlipemia.Methods:Randomized controlled trials(RCTs)published before December 2018 were all aggregated,focusing on evaluation of moxibustion and lipid-lowering drugs for hyperlipemia from PubMed,EMbase,the Cochrane Library,Web of Science,CNKI,CBM,WANFANG database and VIP databases.The quality of the included studies was assessed basing on Cochrane handbook 5.1.0,and the available data were analyzed with RevMan software(version 5.3).Results:Totally 8 RCTs were included with 561 patients.Compared with statins,moxibustion had a better effect to reduce the total cholesterol(TC)(MD=-0.19,95%CI:-0.24,0.13,P<0.001).Moxibustion also had a better effect to reduce low density lipoprotein cholesterol(LDL-C)in compared with statins and fibrates(MD=0.20,95%CI:0.15,-0.25,P<0.001),but there were no significant differences between statins,fibrates and moxibustion in lowering triglyceride(TG)(MD=-0.02,95%CI:-0.09,0.05,P=0.61)and High-density lipoprotein cholesterol(HDL-C)(MD=0.03,95%CI:0.06,0.13,P=0.51).While,compared with the Chinese patent medicine,there was no significant difference in the efficacy of lowering TC(MD=0.05,95%CI:0.17,0.27,P=0.67),TG(MD=-0.08,95%CI:0.41,0.24,P=0.61),LDL-C(MD=-0.14,95%CI:0.38,0.11,P=0.28)and HDL-C(MD=0.11,95%CI:0.01,0.22,P=0.06).Conclusion:Compared with statins and fibrates,moxibustion had advantages in lowering TC and LDL-C,but there was no robust evidence that moxibustion was superior to Chinese patent medicine in improving the blood lipid indexes of patients with hyperlipidemia.展开更多
The cause of asthenozoospermia(AZS)is not well understood because of its complexity and heterogeneity.Although some gene mutations have been identified as contributing factors,they are only responsible for a small num...The cause of asthenozoospermia(AZS)is not well understood because of its complexity and heterogeneity.Although some gene mutations have been identified as contributing factors,they are only responsible for a small number of cases.Radial spokes(RSs)are critical for adenosine triphosphate-driven flagellar beating and axoneme stability,which is essential for flagellum motility.In this study,we found novel compound heterozygous mutations in leucine-rich repeat-containing protein 23(LRRC23;c.1018C>T:p.Q340X and c.881_897 Del:p.R295Gfs*32)in a proband from a nonconsanguineous family with AZS and male infertility.Diff-Quik staining and scanning electron microscopy revealed no abnormal sperm morphology.Western blotting and immunofluorescence staining showed that these mutations suppressed LRRC23 expression in sperm flagella.Additionally,transmission electron microscopy showed the absence of RS3 in sperm flagella,which disrupts stability of the radial spoke complex and impairs motility.Following in vitro fertilization and embryo transfer,the proband’s spouse achieved successful pregnancy and delivered a healthy baby.In conclusion,our study indicates that two novel mutations in LRRC23 are associated with AZS,but successful fertility outcomes can be achieved by in vitro fertilization-embryo transfer techniques.展开更多
Monoclonal antibodies have become a part of daily preparation technologies in many laboratories. Attempts have been made to apply monoclonal antibodies to open a new train of thought for clinical treatments of autoimm...Monoclonal antibodies have become a part of daily preparation technologies in many laboratories. Attempts have been made to apply monoclonal antibodies to open a new train of thought for clinical treatments of autoimmune diseases, inflammatory diseases, cancer, and other immune-associated diseases. This paper is a prospective review to anticipate that monoclonal antibody application in the treatment of myocarditis, an inflammatory disease of the heart, could be a novel approach in the future. In order to better understand the current state of the art in monoclonal antibody techniques and advance applications in myocarditis, we, through a significant amount of literature research both domestic and abroad, developed a systematic elaboration of monoclonal antibodies, pathogenesis of myocarditis, and application of monoclonal antibodies in myocarditis. This paper presents review of the literature of some therapeutic aspects of monoclonal antibodies in myocarditis and dilated cardiomyopathy to demonstrate the advance of monoclonal antibody application in myocarditis and a strong anticipation that monoclonal antibody application may supply an effective therapeutic approach to relieve the severity of myocarditis in the future. Under conventional therapy, myocarditis is typically associated with congestive heart failure as a progressive outcome, indicating the need for alternative therapeutic strategies to improve long-term results. Reviewing some therapeutic aspects of monoclonal antibodies in myocarditis, we recently found that monoclonal antibodies with high purity and strong specificity can accurately act on target and achieve definite progress in the treatment of viral myocarditis in rat model and may meet the need above. However, several issues remain. The technology on how to make a higher homologous and weak immunogenic humanized or human source antibody and the treatment mechanism of monoclonal antibodies may provide solutions for these open issues. If we are to further stimulate progress in the area of clinical decision support, we must continue to develop and refine our understanding and use of monoclonal antibodies in myocarditis.展开更多
Doping electrochemically inert elements in Li-rich layered oxide cathodes usually stabilizes the structure to improve electrochemical performance at the expense of available capacity.Here,we use an element segregation...Doping electrochemically inert elements in Li-rich layered oxide cathodes usually stabilizes the structure to improve electrochemical performance at the expense of available capacity.Here,we use an element segregation principle to realize a uniform surface doping without capacity sacrifice.On the basis of Hume-Rothery rule,element yttrium is chosen as a candidate dopant to spontaneously segregate at particle surface due to mismatched ionic size.Combined with X-ray photoelectron spectroscopy and electron energy loss spectroscopy mapping,yttrium is demonstrated uniformly distributed on particle surface.More importantly,a significant alleviation of oxygen release after surface doping is detected by operando differential electrochemical mass spectrometry.As a result,the modified sample exhibits improved reversibility of oxygen redox with 82.1%coulombic efficiency and excellent cycle performances with 84.15%capacity retention after 140 cycles.Postmortem analysis by transmission electron microscopy,Raman spectroscopy and X-ray diffraction reveal that the modified sample maintains the layered structure without a significant structure transformation after long cycles.This work provides an effective strategy with a series of elements to meet the industrial application.展开更多
基金supported by the National Science Fund for Distinguished Young Scholars(22125804)the National Natural Science Foundation of China(22078155 and 22178163)the National Students'platform for innovation and entrepreneurship training program(20210291013Z).
文摘Solid strong base catalysts are highly attractive for diverse reactions owing to their advantages of neglectable corrosion,facile separation,and environmental friendliness.However,their widespread applications are impeded by basic components aggregation and low stability.In this work,we fabricate single calcium atoms on graphene(denoted as Ca1/G)by use of a redox strategy for the first time,producing solid strong base catalyst with high activity and stability.The precursor Ca(NO_(3))_(2)is first reduced to CaO at 400℃ by the support graphene,forming CaO/G with conventional basic sites,and the subsequent reduction at 850℃results in the generation of Ca1/G with atomically dispersed Ca.Various characterizations reveal that Ca single atoms are anchored on graphene in tetra-coordination(Ca-C_(2)-N_(2))where N is in situ doped from Ca(NO_(3))_(2).The atomically dispersed Ca,along with their anchoring on the support,endow Ca1/G with high activity and stability toward the transesterification reaction of ethylene carbonate with methanol.The turnover frequency value reaches 128.0 h^(-1)on Ca1/G,which is much higher than the traditional counterpart CaO/G and various reported solid strong bases(2.9-46.2 h^(-1)).Moreover,the activity of Ca1/G is well maintained during 5 cycles,while 60%of activity is lost for the conventional analogue CaO/G due to the leaching of Ca.
基金supported by the National Natural Science Foundation of China(No.81573737 and 82074213)the science foundation of Tianjin Municipal Health Bureau(No.2023169 and 2021045)the Tianjin Municipal Health Commission Science and Technology Project(No.TJWJ2022QN057).
文摘Background:Huoxue Tongjiang decoction(HXTJD)is an effective prescription for treating reflux esophagitis(RE).We investigated the effects of HXTJD on esophageal motility and mucosal inflammation in a rat RE model.Methods:Chemical composition of HXTJD was analyzed by ultrahigh-performance liquid chromatography Q-Orbitrap mass spectrometry(MS).The change rates of mean contraction tension forces,mean amplitudes,and mean frequencies for the lower esophageal sphincter(LES)were recorded using the isolated tissue bath system,mechanical tension transducer,and PowerLab physiological recorder.After weighing the stomach,the phenol red labeling method was used to measure the gastric emptying rate.The LES ultrastructure was observed through transmission electron microscopy.Immunofluorescence and western blotting were used to detect the number of interstitial cells of Cajal(ICC)and the expression levels of c-kit protein,connexin43(Cx43),and stem cell factor(SCF).Flow cytometric analysis and enzyme-linked immunosorbent assay were conducted to detect the percentages of T helper 17(Th17)cells and regulatory T(Treg)cells and the serum concentrations of interleukin 6(IL-6),interleukin 17(IL-17),and interleukin 10(IL-10)in the rats.Results:We identified 28 chemical constituents in HXTJD.Regarding esophageal motility,we revealed that HXTJD increased the mean contraction tension forces,mean amplitudes,and mean frequency change rate of LES and the gastric emptying rate;decreased stomach weight;and improved the LES ultrastructure.Additionally,HXTJD increased the number of ICC-positive cells,and c-kit,Cx43,and SCF expression levels.Regarding esophageal inflammation,HXTJD significantly decreased the percentage of Th17 cells,and IL-6 and IL-17 concentrations,and increased the percentage of Treg cells and IL-10 concentration.Conclusion:HXTJD was found to be efficacious in the rat RE model.It may promote esophageal motility and alleviate the inflammatory response by activating the SCF/c-kit/ICC pathway and regulating the Th17/Treg cell balance.
基金supported by Medical Science Foundation of Health Department (under contract No. H201034)Six Talent Summit Foundation of Jiangsu Province, China (under contract No. 2010-WS081)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘The objective of this study was to investigate the mechanical characteristics of implant-abutment interface design in a dental implant system, using nonlinear finite element analysis (FEA) method. This finite element simulation study was applied on three commonly used commercial dental implant systems: model I, the reduced-diameter 3i implant system (West Palm Beach, FL, USA) with a hex and a 12-point double internal hexagonal connection; model II, the Semados implant system (Bego, Bremen, Germany) with combination of a conical (45° taper) and internal hexagonal connection; and model III, the Br,~nemark implant system (Nobel Biocare, Gothenburg, Sweden) with external hexagonal connection. In simulation, a force of 170 N with 45°oblique to the longitudinal axis of the implant was loaded to the top surface of the abutment. It has been found from the strength and stiffness analysis that the 3i implant system has the lowest maximum yon Mises stress, prirlcipal stress and displacement, while the Br^nemark implant system has the highest. It was concluded from our preliminary study using nonlinear FEA that the reduced-diameter 3i implant system with a hex and a 12-point double internal hexagonal connection had a better stress distribution, and produced a smaller displacement than the other two implant systems.
基金Supported by the National Natural Science Foundation of China(General Program),No.81972726.
文摘Hepatocellular carcinoma(HCC)is the fourth leading cause of cancer-related deaths worldwide.The prognosis of patients with HCC remains poor largely due to the late diagnosis and lack of effective treatments.Despite being widely used,alpha-fetoprotein serology and ultrasonography have limited diagnostic performance for early-stage HCC.The emergence of omics strategies has contributed to significant advances in the development of non-invasive biomarkers for the early diagnosis of HCC including proteins,metabolites,circulating tumor deoxyribonucleic acid,and circulating non-coding ribonucleic acid.Early diagnosis is beneficial to patients as it increases the proportion who can be treated with curative treatment,thus prolonging survival outcomes.Currently,multiple clinical trials involving locoregional,systemic therapies,and combinations of these modalities are changing therapeutic strategies for different stage HCC.Success in several preclinical trials that involve immunotherapeutic innovations has created the potential to complement and enforce other treatment strategies in the future.This review summarizes the most recent advances in noninvasive early molecular detection,current therapy strategies,and potential immunotherapeutic innovations of HCC.
基金Project supported by the National Key Research and Development Program of China(Grant Nos.2018YFA0208403 and 2016YFA0200403)the National Natural Science Foundation of China(Grant Nos.51472057,11874129,91323304,and 11674387)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA09040101)the Baotou Rare Earth Research and Development Centre,Chinese Academy of Sciences(Grant No.GZR 2018001)
文摘In this work we report that after single-walled carbon nanotubes(SWNTs) are sheared with a pair of titanium scissors,the magnetization becomes larger than that of the corresponding pristine ones. The magnetization increases proportionally with the number of SWNTs with sheared ends, suggesting that there exist magnetic moments at the sheared ends of SWNTs.By using the coefficient of this linear relation, the average magnetic moment is estimated to be 41.5 ± 9.8 μB(Bohr magneton) per carbon atom in the edge state at temperature of 300.0 K, suggesting that ultrahigh magnetic fields can be produced. The dangling sigma and pi bonds of the carbon atoms at sheared ends play important roles in determining the unexpectedly high magnetic moments, which may have great potential applications.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 61704124, 11690042, and 61634005).
文摘Trapping effect in normally-off Al2O3/AlGaN/GaN metal–oxide–semiconductor (MOS) high-electron-mobility transistors (MOS-HEMTs) with post-etch surface treatment was studied in this paper. Diffusion-controlled interface oxidation treatment and wet etch process were adopted to improve the interface quality of MOS-HEMTs. With capacitance–voltage (C–V) measurement, the density of interface and border traps were calculated to be 1.13 × 10^12 cm^−2 and 6.35 × 10^12 cm^−2, effectively reduced by 27% and 14% compared to controlled devices, respectively. Furthermore, the state density distribution of border traps with large activation energy was analyzed using photo-assisted C–V measurement. It is found that irradiation of monochromatic light results in negative shift of C–V curves, which indicates the electron emission process from border traps. The experimental results reveals that the major border traps have an activation energy about 3.29 eV and the change of post-etch surface treatment process has little effect on this major activation energy.
文摘BACKGROUND Neisseria mucosa is a gram negative diplococcus belonging to the genus Neisseria found commonly in the upper respiratory tract.It is typically a commensal organism when it is parasitic on oral and nasal mucosa.To our knowledge,it does not cause disease in healthy individuals with normal immunity,but can be pathogenic in those with impaired immune function or change in bacterial colonization site.Neisseria mucosa has been reported to cause bacterial meningitis,conjunctivitis,pneumonia,endocarditis,peritonitis and urethritis.However,peritoneal dialysis-related peritonitis caused by Neisseria mucosa is extremely rare in clinical practice,which has not previously been reported in China.CASE SUMMARY A 55-year-old female presented to the nephrology clinic with upper abdominal pain without apparent cause,accompanied by nausea,vomiting and diarrhea for two days.The patient had a history of Stage 5 chronic kidney disease for five years,combined with renal hypertension and renal anemia,and was treated with peritoneal dialysis for renal replacement therapy.The patient was subsequently diagnosed with peritoneal dialysis-related peritonitis.Routine examination of peritoneal dialysis fluid showed abdominal infection,and the results of microbial culture of the peritoneal dialysis fluid confirmed Neisseria mucosa.Imi-penem/cilastatin 1.0 g q12h was added to peritoneal dialysis fluid for anti-infection treatment.After 24 d,the patient underwent upper extremity arteriovenous fistulation.One month later,the patient was discharged home in a clinically stable state.CONCLUSION Peritonitis caused by Neisseria mucosa is rare.Patients with home-based self-dialysis cannot guarantee good medical and health conditions,and require education on self-protection.
基金supported by grants from the Fundamental Research Funds for the Central Universities(No.2042022kf1215)the Special Funds for Innovation in Scientific Research Program of Zhongshan(No.2020AG024)+4 种基金Chinese Foundation for Hepatitis Prevention and Control:TianQing Liver Disease Research Fund Subject(No.TGQB20210109)the Open Funds of Key Laboratory of Diagnosis and Treatment of Digestive System Tumors of Zhejiang Province(No.KFJJ-202005 and No.KFJJ-201907)the Open Research Program of the State Key Laboratory of Virology of China(No.2021KF002 and No.2021KF006)the Natural Science Foundation of Hubei Province(No.2020CFB619)Wuhan Municipal Health Research Foundation(No.WX21Z36).
文摘Objective To investigate the epidemiological features in children after the coronavirus disease 2019(COVID-19)pandemic.Methods This study collected throat swabs and serum samples from hospitalized pediatric patients of Renmin Hospital of Wuhan University,Wuhan,Hubei province,China before and after the COVID-19 pandemic.Respiratory infected pathogens[adenovirus(ADV),influenza virus A/B(Flu A/B),parainfluenza virus 1/2/3(PIV1/2/3),respiratory syncytial virus(RSV),Mycoplasma pneumoniae(MP),and Chlamydia pneumoniae(CP)]were detected.The pathogens,age,and gender were used to analyze the epidemiological features in children after the COVID-19 pandemic.Results The pathogen detection rate was significantly higher in females than in males(P<0.05),and the infection of PIV1 and MP was mainly manifested.After the COVID-19 pandemic,PIV1,PIV3,RSV,and MP had statistically different detection rates among the age groups(P<0.05),and was mainly detected in patients aged 0–6 years,0–3 years,0–3 years,and 1–6 years,respectively.When comparing before the COVID-19 pandemic,the total detection rate of common respiratory pathogens was lower(P<0.05).Except for the increase in the detection rate of PIV1 and CP,the infection rate of other pathogens had almost decreased.Conclusion The prevention and control measures for the COVID-19 pandemic effectively changed the epidemiological features of common respiratory tract infectious diseases in pediatric children.
文摘BACKGROUND Salmonella derby(S.derby)is a Gram-negative diplococcus that is common in the digestive tract.Infected patients generally experience symptoms such as fever and diarrhea.Mild cases are mostly self-healing gastroenteritis,and severe cases can cause fatal typhoid fever.Clinical cases are more common in children.The most common form of S.derby infection is self-healing gastroenteritis,in which,fever lasts for about 2 d and diarrhea for<7 d.S.derby can often cause bacterial conjunctivitis,pneumonia,endocarditis,peritonitis and urethritis.However,intracranial infections in infants caused by S.derby are rare in clinical practice and have not been reported before in China.CASE SUMMARY A 4-mo-old female infant had recurrent fever for 2 wk,with a maximum body temperature of around 39.4°C.Treatment for infectious fever in a local hospital was ineffective,and she was admitted to our hospital.Before admission,there was one sudden convulsion,characterized by unclear consciousness,limb twitching,gaze in both eyes,and slight cyanosis on the face.Cerebrospinal fluid(CSF)culture was positive for Gram-negative bacilli,which conformed to S.derby.After treatment with meropenem and ceftriaxone antibiotics,the patient was discharged home in a clinically stable state after 4 wk of treatment.CONCLUSION We reported a rare case of S.derby cultured in CSF.S.derby enters the CSF through the blood–brain barrier,causing purulent meningitis.If not treated timeously,it can lead to serious,life-threatening infection.
基金supported by the Independent Topic Project of China Academy of Chinese Medical Sciences(No.ZZ12007)the National Natural Science Foundation of China(No.81473780).
文摘Backgroud:The electroacupuncture of auricular concha area(EA-ACR)proved to have a good regulatory effect on insomnia and the release of melatonin,which is most closely related to sleep.However,there is little research to demonstrate the relationship between EA-ACR and melatonin.The objective of present study is to observe the effects of EA-ACR on the circadian rhythm of melatonin secretion in p-chlorophenylalanine(PCPA)-induced insomnia rats.Methods:The study divided 36 male Sprague-Dawley rats randomly into three groups:12 in blank group,12 in model group,and 12 in EA-ACR group.By using PCPA intraperitoneal injection for 2 days,insomnia model was established.EA-ACR group was treated for 28 days.We observed the effects of EA-ACR on the rats'behavioral changes,open-field test and weight during the experiment.After the experiment,the rat tail and heart blood were collected,and the melatonin was detected by enzyme-linked immunosorbent assay.Results:Compared with the blank group,28–30 hours after PCPA intraperitoneal injection,the circadian rhythm of sleep and the total sleep time of model rats decreased.Compared with the model group,electrical stimulation in the ear concha region could effectively reverse the behavioral changes of rats,and increase the trend of weight growth(P=0.010),the crossing score(P=0.014),vertical motion score(P=0.015)and the level of plasma melatonin secretion(P=0.020)with the trend showing a rhythmic pattern(0–60 minutes upward,60–120 minutes downward,120–150 minutes upward).Conclusion:EA-ACR can improve the quality of life(weight),ameliorate exploring irritable and anxiety behaviors in PCPA-induced insomnia rats.The underlying effects of EA-ACR may be excited on the circadian rhythm of melatonin secretion in PCPA-induced insomnia rats.
基金the National Natural Science Foundation of China(81972726,81871949 and 82171834)Jiangsu Six Talent Peaks Project(WSN-102).
文摘Background:Current surveillance strategies for hepatocellular carcinoma(HCC)among patients with non-alcoholic fatty liver disease(NAFLD)are insufficient.This study aimed to investigate the diagnostic perfor-mance of alpha-fetoprotein(AFP),protein induced by vitamin K absence or antagonist-Ⅱ(PIVKA-Ⅱ),lens culinaris agglutinin-reactive fraction of AFP(AFP-L3),and their combinations in HCC underlying NAFLD patients.Methods:Serologic AFP,AFP-L3,and PIVKA-Ⅱ levels in NAFLD patients with and without HCC were mea-sured.By receiver operating characteristic(ROC)analyses,the area under the curve(AUC),sensitivity,and specificity were obtained to evaluate the diagnostic accuracy of each biomarker and their combinations.Results:This study was conducted on 139 patients with NAFLD-HCC and 345 NAFLD controls.The eleva-tion of these three biomarkers was observed in patients with NAFLD-HCC compared to those in NAFLD controls(all P<0.001).When they were analyzed individually,PIVKA-Ⅱ showed the best performance in diagnosing any-stage HCC with an AUC of 0.869,followed by AFP(0.763;vs.PIVKA-Ⅱ,P<0.001)and AFP-L3(0.689;vs.PIVKA-II,P<0.001).When they were analyzed in combination,AFP+PIVKA-Ⅱ yielded the highest AUC(0.906),followed by AFP+PIVKA-II+AFP-L3(0.904;vs.AFP+PIVKA-Ⅱ,P=0.086),PIVKA-Ⅱ+AFP-L3(0.881;vs.AFP+PIVKA-II,P<0.001),and AFP+AFP-L3(0.759;vs.AFP+PIVKA-II,P<0.001).Similar findings were obtained in the subgroup with early-stage NAFLD-HCC,as well as the non-cirrhotic subgroup.Conclusions:These data validated the better diagnostic ability of PIVKA-II than AFP or AFP-L3 alone for diagnosing any-stage HCC among patients with NAFLD,and the combination of AFP+PIVKA-II signifi-cantly improved the diagnostic accuracy of NAFLD-HCC.
基金supported by the National SKA Program of China,No. 2020SKA0120104the Natural Science Foundation of Shanghai,No. 20ZR1467600。
文摘The Tian-ma Radio Telescope(TMRT) applies an Active Surface System(ASFS), which corrects for large-scale deformations due to gravity and thermal on the primary reflector. The centralized and automated management of the ASFS using software has become a challenge, for which we have developed the TMRT Active Surface System Control Software(TASCS). This paper describes the design and implementation of TASCS for device control,status monitoring, human-computer interaction, and data management functionalities. TASCS adopts the opensource Tango Controls framework and distributes middleware technology to realize real-time automated adjustment of the primary reflector through remote centralized control of a large number of actuators. At present, it has been successfully deployed on the TMRT and has played an important role in Event Horizon Telescope observations.
基金Project supported by the Fundamental Research Funds for the National Key Research and Development Program, China (Grant No. 2020YFB1807403)the National Natural Science Foundation of China (Grant Nos. 62174125, 62188102, and 62131014)。
文摘This paper reports a low-damage interface treatment process for Al N/Ga N high electron mobility transistor(HEMT)and demonstrates the excellent power characteristics of radio-frequency(RF) enhancementmode(E-mode) Al N/Ga N HEMT. An RF E-mode device with 2.9-nm-thick Al N barrier layer fabricated by remote plasma oxidation(RPO) treatment at 300℃. The device with a gate length of 0.12-μm has a threshold voltage(Vth) of 0.5 V, a maximum saturation current of 1.16 A/mm, a high Ion/Ioff ratio of 1×108, and a 440-m S/mm peak transconductance. During continuous wave(CW) power testing, the device demonstrates that at 3.6 GHz, a power added efficiency is 61.9% and a power density is 1.38 W/mm, and at 30 GHz, a power added efficiency is 41.6% and a power density is 0.85 W/mm. Furthermore, the RPO treatment improves the mobility of RF E-mode Al N/Ga N HEMT. All results show that the RPO processing method has good applicability to scaling ultrathin barrier E-mode Al N/Ga N HEMT for 5G compliable frequency ranging from sub-6 GHz to Ka-band.
文摘Objective:Systematically compared the effects of moxibustion and lipid-lowering drugs on hyperlipemia.Methods:Randomized controlled trials(RCTs)published before December 2018 were all aggregated,focusing on evaluation of moxibustion and lipid-lowering drugs for hyperlipemia from PubMed,EMbase,the Cochrane Library,Web of Science,CNKI,CBM,WANFANG database and VIP databases.The quality of the included studies was assessed basing on Cochrane handbook 5.1.0,and the available data were analyzed with RevMan software(version 5.3).Results:Totally 8 RCTs were included with 561 patients.Compared with statins,moxibustion had a better effect to reduce the total cholesterol(TC)(MD=-0.19,95%CI:-0.24,0.13,P<0.001).Moxibustion also had a better effect to reduce low density lipoprotein cholesterol(LDL-C)in compared with statins and fibrates(MD=0.20,95%CI:0.15,-0.25,P<0.001),but there were no significant differences between statins,fibrates and moxibustion in lowering triglyceride(TG)(MD=-0.02,95%CI:-0.09,0.05,P=0.61)and High-density lipoprotein cholesterol(HDL-C)(MD=0.03,95%CI:0.06,0.13,P=0.51).While,compared with the Chinese patent medicine,there was no significant difference in the efficacy of lowering TC(MD=0.05,95%CI:0.17,0.27,P=0.67),TG(MD=-0.08,95%CI:0.41,0.24,P=0.61),LDL-C(MD=-0.14,95%CI:0.38,0.11,P=0.28)and HDL-C(MD=0.11,95%CI:0.01,0.22,P=0.06).Conclusion:Compared with statins and fibrates,moxibustion had advantages in lowering TC and LDL-C,but there was no robust evidence that moxibustion was superior to Chinese patent medicine in improving the blood lipid indexes of patients with hyperlipidemia.
基金supported by the National Key Research and Development Program of China(No.2022YFC2702702)National Natural Science Foundation of China(No.32270899 and No.32070842)+2 种基金the Natural Science Foundation of Jiangsu Province(No.BK20230004)Young and Middle-Aged Key Personnel Training Project of the Fujian Provincial Health Commission(2019-ZQN-62)Fujian Provincial Finance Project(BPB-TSX2021).
文摘The cause of asthenozoospermia(AZS)is not well understood because of its complexity and heterogeneity.Although some gene mutations have been identified as contributing factors,they are only responsible for a small number of cases.Radial spokes(RSs)are critical for adenosine triphosphate-driven flagellar beating and axoneme stability,which is essential for flagellum motility.In this study,we found novel compound heterozygous mutations in leucine-rich repeat-containing protein 23(LRRC23;c.1018C>T:p.Q340X and c.881_897 Del:p.R295Gfs*32)in a proband from a nonconsanguineous family with AZS and male infertility.Diff-Quik staining and scanning electron microscopy revealed no abnormal sperm morphology.Western blotting and immunofluorescence staining showed that these mutations suppressed LRRC23 expression in sperm flagella.Additionally,transmission electron microscopy showed the absence of RS3 in sperm flagella,which disrupts stability of the radial spoke complex and impairs motility.Following in vitro fertilization and embryo transfer,the proband’s spouse achieved successful pregnancy and delivered a healthy baby.In conclusion,our study indicates that two novel mutations in LRRC23 are associated with AZS,but successful fertility outcomes can be achieved by in vitro fertilization-embryo transfer techniques.
基金Project supported by the Beijing Municipal Natural Science Foun-dation(No.7122168)the Beijing Nova Programme (No.2008B54),China
文摘Monoclonal antibodies have become a part of daily preparation technologies in many laboratories. Attempts have been made to apply monoclonal antibodies to open a new train of thought for clinical treatments of autoimmune diseases, inflammatory diseases, cancer, and other immune-associated diseases. This paper is a prospective review to anticipate that monoclonal antibody application in the treatment of myocarditis, an inflammatory disease of the heart, could be a novel approach in the future. In order to better understand the current state of the art in monoclonal antibody techniques and advance applications in myocarditis, we, through a significant amount of literature research both domestic and abroad, developed a systematic elaboration of monoclonal antibodies, pathogenesis of myocarditis, and application of monoclonal antibodies in myocarditis. This paper presents review of the literature of some therapeutic aspects of monoclonal antibodies in myocarditis and dilated cardiomyopathy to demonstrate the advance of monoclonal antibody application in myocarditis and a strong anticipation that monoclonal antibody application may supply an effective therapeutic approach to relieve the severity of myocarditis in the future. Under conventional therapy, myocarditis is typically associated with congestive heart failure as a progressive outcome, indicating the need for alternative therapeutic strategies to improve long-term results. Reviewing some therapeutic aspects of monoclonal antibodies in myocarditis, we recently found that monoclonal antibodies with high purity and strong specificity can accurately act on target and achieve definite progress in the treatment of viral myocarditis in rat model and may meet the need above. However, several issues remain. The technology on how to make a higher homologous and weak immunogenic humanized or human source antibody and the treatment mechanism of monoclonal antibodies may provide solutions for these open issues. If we are to further stimulate progress in the area of clinical decision support, we must continue to develop and refine our understanding and use of monoclonal antibodies in myocarditis.
基金This work was financially supported by S&T Innovation 2025 Major Special Programme of Ningbo(Grant No.2018B10081)"Lingyan"Research and Development Plan of Zhejiang Province(Grant No.2022C01071)+2 种基金the National Natural Science Foundation of China(Grant No.21773279)the Natural Science Foundation of Ningbo(Grant Nos.202003N4030,202003N4347)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2022299).
文摘Doping electrochemically inert elements in Li-rich layered oxide cathodes usually stabilizes the structure to improve electrochemical performance at the expense of available capacity.Here,we use an element segregation principle to realize a uniform surface doping without capacity sacrifice.On the basis of Hume-Rothery rule,element yttrium is chosen as a candidate dopant to spontaneously segregate at particle surface due to mismatched ionic size.Combined with X-ray photoelectron spectroscopy and electron energy loss spectroscopy mapping,yttrium is demonstrated uniformly distributed on particle surface.More importantly,a significant alleviation of oxygen release after surface doping is detected by operando differential electrochemical mass spectrometry.As a result,the modified sample exhibits improved reversibility of oxygen redox with 82.1%coulombic efficiency and excellent cycle performances with 84.15%capacity retention after 140 cycles.Postmortem analysis by transmission electron microscopy,Raman spectroscopy and X-ray diffraction reveal that the modified sample maintains the layered structure without a significant structure transformation after long cycles.This work provides an effective strategy with a series of elements to meet the industrial application.