Objective:To observe the effects of pidotimod combined with ribavirin on inflammatory factors, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin in children with hand-foot-mouth disease.Methods:...Objective:To observe the effects of pidotimod combined with ribavirin on inflammatory factors, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin in children with hand-foot-mouth disease.Methods: A total of 108 children with foot-hand-and-mouth epidemic in our hospital from Jan. 2013-Dec. 2016 were divide into the observation group and the control group, each groups has 54 cases. Two groups of children were treated with isolation, the observation group was given pidotimod combined with ribavirin, and the control group was treated with ribavirin. 5 mL venous blood of two group patients were collected at admission and after 6 d treatment, respectively, to compare inflammatory factor, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin in two groups.Results: Before treatment, the levels of inflammatory factor, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin of two groups were not statistically significant. Compared with groups after treatment, the levels of CRP, IL-6, TNF-α were lower than that before treatment, CRP (2.23±0.37) mg/L, IL-6 (21.24±9.81) pg/mL and TNF-α (56.97±50.36) pg/mL levels in observation group after treatment were significantly lower than those in control group, the difference was statistically significant. After treatment, the levels of CD3, CD4, CD4/CD8, IgG, IgA and IgM in control group were significantly higher than that before treatment, the difference was statistically significant;After treatment, the levels of CD3 (51.26±10.27)%, CD4 (36.36±4.09)% and CD4/CD8 (1.60±0.47), IgG (10.24±1.82) mg/L, IgA (1.30±0.31) mg/L and IgM (1.48±0.30) mg/L in observation group were significantly higher than in control group, the difference was statistically significant. After treatment, the levels of lactate, D-dimer and procalcitonin in two groups were significantly lower than that before treatment, the difference was statistically significant;After treatment, the levels of lactate (1.19±0.20) mmol/L, D-dimer (150.23±27.21) ng/mL, and procalcitonin (0.08±0.02) ng/mL in observation group were significantly higher than in control group, the difference was statistically significant. Conclusion: Pidotimod combined with ribavirin has a pronounced effect on children with hand-foot-mouth disease, which can effectively reduce the body's inflammatory response, enhance immune function, improve clinical biochemical indicators, and should be widely recommended for clinical use.展开更多
BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following ...BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following the introduction of EV-A71 vaccines in China since 2016,the situation could change.CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China.However,the epidemiological characteristics of central China remain unknown.AIM To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City,central China,in recent years.METHODS The epidemiological,clinical,and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed.196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020.To detect and genotype enteroviruses,real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used.In Shiyan,168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes.Based on the logistic regression model,the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan.RESULTS From 2016 to 2020,35840 HFMD cases were reported in Shiyan.The number of cases decreased by 48.4%from 2016 to 2017.Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year,respectively.In 2020,a decrease of about 85.5%was reported when compared to 2019.The most common serotypes shifted from EV-A71 and CV-A16(about 60%-80%in 2016 and 2018)to others(more than 80.0%in 2017,2019,and 2020).EV-A71 lost its dominance in 2017 in Shiyan.Among 196 confirmed HFMD cases,85.7%tested positive for enterovirus,with CV-A6 being the most common serotype(121/168,72.0%).The positive rates for CV-A16 and CVA10 were 4.8%and 3.0%,respectively.There was no EV-A71 discovered.Infection with CV-A6 was linked to fever,myocardial damage,increased creatine kinase MB isoenzyme,and lactate dehydrogenase levels.CONCLUSION CV-A6 was the most common enterovirus serotype in Shiyan City,replacing EV-A71 and CV-A16 as the HFMD pathogen.Developing vaccines against CV-A6 or multiple pathogens,as well as rising CV-A6 surveillance,will help prevent HFMD in central China.展开更多
Understanding the mechanisms and spatial correlations of crystallographic symmetry breaking in ferroelectric materials is essential to tuning their functional properties.While optical second harmonic generation(SHG)ha...Understanding the mechanisms and spatial correlations of crystallographic symmetry breaking in ferroelectric materials is essential to tuning their functional properties.While optical second harmonic generation(SHG)has long been utilized in ferroelectric studies,its capability for probing complex polar materials has yet to be fully realized.Here,we develop a SHG spectral imaging method implemented on a home-designed laser-scanning SHG microscope,and demonstrate its application for a model system of(K,Na)NbO3 single crystals.Supervised model fitting analysis produces comprehensive information about the polarization vector orientations and relative fractions of constituent domain variants as well as their thermal evolution across the polymorphic phase transitions.Multiple domains and phases are clearly delineated at different temperatures,suggesting the phase competitions in(K,Na)NbO3.Besides,we show that unsupervised matrix decomposition analysis can quickly and faithfully reveal domain configurations without a priori knowledge about specific material systems.The SHG spectral imaging method can be readily extended to other ferroelectric materials with potentials to be further enhanced.展开更多
NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is no...NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is not conducive to energy storage applications.Our previous work found that incorporating CaHfO_(3) into NaNbO_(3) can stabilize its antiferroelectric phase by reducing the tolerance factor(t),as indicated by the appearance of characteristic double P-E loops.Furthermore,a small amount of MnO_(2) addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO_(3)-0.06CaHfO_(3)(0.94NN-0.06CH),which can further improve the stability of antiferroelectricity.The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO_(2).The antiferroelectric orthorhombic phase first increases and then decreases,while the t shows the reversed trend,thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm^(3) at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO_(2)(in mass fraction).With the increase of Mn content to 1.0%from 0.5%,the efficiency increases to 81% from 45%,although the energy storage density decreases to 1.31 J/cm^(3) due to both increased tolerance factor and non-polar phase.展开更多
There has been a surge of research interest in the promising lead-free potassium-sodium niobate(KNN)-based ceramics,applications of which could be significantly promoted by improving thermal stability of piezoelectric...There has been a surge of research interest in the promising lead-free potassium-sodium niobate(KNN)-based ceramics,applications of which could be significantly promoted by improving thermal stability of piezoelectricity.Besides,endowing the KNN-based ceramics with photoluminescence property by rare-earth-ion doping can make them more completive lead-free counterparts in potential applications such as novel multifunctional sensing devices.Herein,a novel KNN-based ceramic material doped with Eu was elaborately designed to simultaneously obtain enhanced temperaturestable piezoelectricity and good luminescence property.By the introduction of diffused phase transition and the modulation of unit cell distortion,a large piezoelectric strain coefficient(d^(*)_(33))with a small variation(590±59 pm/V)over a wide temperature range(from room temperature to 110℃)was realized.The optimal composition also exhibited a considerable piezoelectric coefficient(d_(33))with small fluctuation(330±33 pC/N)from 20 to 80℃.In addition to the enhanced temperature-stable piezoelectricity,the luminescence of these ceramics was slightly enhanced with the elevation of BaZrO_(3)(BZ)doping contents,which could be attributed to the increased compositional disorder and the decreased unit cell distortion of the matrix material.Moreover,an optical characteristic was more prominent at ultra-low temperatures.This work unprecedentedly provides a novel paradigm for the design of multifunctional KNN-based ceramics with enhanced temperature-stable piezoelectricity and good luminescence property,revealing the great potential of the rare-earth-element-doped KNN material for future applications in the novel multifunctional devices.展开更多
Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for ex...Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for example,resonators,filters,or phase shifters.However,it is dificult to simultaneously achieve these characteristics by traditional strategies,such as doping and strain modifying.Here,we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc_(1/2)Nb_(1/2))_(0.9)(Mg_(1/3)Nb_(2/3))_(0.O3)(PSNMN)thin film can be almost doubled from~47%to~80.0%(at 10kHz)at a low electric field(~530kV/cm),and the dielectric loss can be sharply reduced by more than an order of magnitude,from~0.50 to~0.037(at 1 kHz)when the thin flm was annealed in air at 650℃ for 15h under the help of an atmosphere-compensating-block(ACB)made from the proto-PSNMN gel.Moreover,the PSNMN thin flm annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range(>130 K),which could be attributed to the Maxwell-Wagner(MW)effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process.The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possibie MW efects,and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy.The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'_(1/2)B"_(1/2))O3 ferroelectric thin films with a B-site nanoscale-ordered structure,meanwhile it paves the way for ultraintergrated tunable thin-flm-devices with great phase shifter performance in practical applications.展开更多
Most widely used piezoelectric ceramics are based on Pb(Zr,Ti)O3(PZT)composition which has adverse environmental and health effects due to its high lead content.Environmental and safety concerns with respect to the ut...Most widely used piezoelectric ceramics are based on Pb(Zr,Ti)O3(PZT)composition which has adverse environmental and health effects due to its high lead content.Environmental and safety concerns with respect to the utilization,recycling,and disposal of lead-based piezoelectric ceramics have induced a new surge in developing lead-free piezoelectric ceramics.Among all the lead-free ceramics,(K,Na)NbO3(KNN)has drawn increasing attention because of its well-balanced piezoelectric properties and better environmental compatibility.On basis of the author’s work,this review summarizes the progress that has been made in recent years on development of KNN-based piezoelectric ceramics,including crystallographic structure and phase transition analysis,pressurized solid-state sintering as well as liquid-phase-assisted sintering process,and poling treatment for property enhancement.All in all,KNN is a promising lead-free system,but more research is still required both from academic and industrial interests.展开更多
CuWO4,as an n-type oxide semiconductor with a bandgap of 2.2 eV,has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations.However,rapid charge recombi...CuWO4,as an n-type oxide semiconductor with a bandgap of 2.2 eV,has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations.However,rapid charge recombination greatly hinders its practical applications.Herein,we present a cascaded electron transition pathway in a ternary heterostructure consisting of CdS quantum dots,carbon dots(CDs)and CuWO4 hollow spheres,which proves to greatly facilitate the photogenerated electron-hole separation,and eventually boosts the degradation efficiency of phenol and congo red by 100%and 46%compared to bare CuWO4.The enhanced performance of the CuWO4/CdS/CDs heterostructure mainly originates from the unidirectional electron migration from CdS to CuWO4 and then to the organics through CDs.This work elucidates the electron transfer kinetics in multi-phase system and provides a new design paradigm for optimizing the properties of CuWO4 based photocatalysts.展开更多
Developing high-efficiency materials with earth-abundant and low-toxicity elements has become a popular trend in the field of thermoelectrics.Among these compounds,oxides and sulfides,the lighter,cheaper and green ana...Developing high-efficiency materials with earth-abundant and low-toxicity elements has become a popular trend in the field of thermoelectrics.Among these compounds,oxides and sulfides,the lighter,cheaper and green analogies of tellurides,have been extensively investigated and summarized as well defined classes.Nonetheless,the vast family of selenides with better electrical performance,lower thermal conductivity and higher thermoelectric efficiency have not been specially discussed.Here in this review,we present recent advances in binary and multinary selenide thermoelectric materials,covering traditional PbSe,liquid-like Cu_(2)Se,layered SnSe,diamond-like and disordered multinary compounds.The features of selenides are discussed based on both environmental concerns and from the perspective of chemical bonding,transport properties and performance.Emphasis is put on the“compositionstructure-processing-performance”relationship,and some interesting issues are addressed.Finally,challenges for thermoelectric selenides are discussed,and possible optimization strategies are also suggested.展开更多
Polarization switching in lead-free(K0.40Na0.60)NbO3(KNN)single crystals was studied by switching spectroscopy piezoresponse force microscopy(SS-PFM).Acquisition of multiple hysteresis loops on a closely spaced square...Polarization switching in lead-free(K0.40Na0.60)NbO3(KNN)single crystals was studied by switching spectroscopy piezoresponse force microscopy(SS-PFM).Acquisition of multiple hysteresis loops on a closely spaced square grid enables polarization switching parameters to be mapped in real space.Piezoresponse amplitude and phase hysteresis loops show collective symmetric/asymmetric characteristics,affording information regarding the switching behavior of different domains.As such,the out-of-plane polarization states of the domains,including amplitudes and phases can be determined.Our results could contribute to a further understanding of the relationships between polarization switching and polarization vectors at the nanoscale,and provide a feasible method to correlate the polarization hysteresis loops in a domain under an electric field with the polarization vector states.展开更多
Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracte...Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals;in particular,a higher out-of-plane ZT value could be achieved in ntype SnSe due to its 3D charge and 2D phonon transports.In this work,the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural microstructure.The textures were fabricated using mechanical alloying and repeated spark plasma sintering(SPS),as a kind of hot pressing,aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline SnSe.Results show that the lowest thermal conductivity of 0.36 Wm^(-1) K^(-1) was obtained at 783 K in perpendicular to texture direction.Interestingly,the electrical transport properties are less anisotropic and even nearly isotropic,and the power factors reach 681.3μWm^(-1) K^(-2) at 783 K along both parallel and perpendicular directions.The combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 K.The high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe,and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.展开更多
Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so fa...Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS polycrystals.This work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier mobility.As a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S sample.Interestingly,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS sample.Moreover,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.展开更多
BiFeO_(3),a room-temperature multiferroic material,has recently been increasingly applied as a potential lead-free piezoelectric material due to its large piezoelectricity achieved by doping.In this work,12%Smdoped Bi...BiFeO_(3),a room-temperature multiferroic material,has recently been increasingly applied as a potential lead-free piezoelectric material due to its large piezoelectricity achieved by doping.In this work,12%Smdoped BiFeO_(3)epitaxial thin films were fabricated on Nb-doped SrTiO_(3)(001)single crystal substrates via sol-gel method.The epitaxy was verified by reciprocal space mapping(RSM)and transmission electron microscope(TEM).The TEM results indicated the coexistence of R3c and Pbam phases in the film.The domains and piezoelectric properties from room temperature to 200℃were characterized by piezoresponse force microscopy(PFM).Domains became active from 110℃to 170℃,and domain configurations changed obviously.A partially fading piezoresponse indicated the emergence of antiferroelectric Pbam.The in-situ domain analysis suggested that the phase transition was accompanied by domain wall motion.Switching spectroscopy PFM(SS-PFM)was further conducted to investigate the piezoresponse during the phase transition.Anomalous responses were found in both ON and OFF states at 170℃,and the film exhibits typical antiferroelectric behavior at 200℃,implying that the completion of phase transition and structure turned to the Pbam phase.This work revealed the origin of the high piezoresponse of Sm-doped BiFeO_(3)thin films at the morphotropic phase boundary(MPB).展开更多
Isobaric specific heat capacity(Cp)is an important parameter not only in physics but also for most materials.Its accurate measurement is particularly critical for performance evaluation of thermoelectric materials,but...Isobaric specific heat capacity(Cp)is an important parameter not only in physics but also for most materials.Its accurate measurement is particularly critical for performance evaluation of thermoelectric materials,but the experiments by differential scanning calorimetry(DSC)often lead to large uncertainties in the measurements,especially at elevated temperatures.In this study,we propose a simple method to determine Cp by measuring the sound velocity(υ)based on lattice vibration and expansion theory.The relative standard error of theυis smaller than 1%,showing good accuracy and repeatability.The calculated Cp at elevated temperature(>300 K)increases slightly with increasing temperature due to the lattice expansion,which is more reasonable than the Dulong–Petit value.展开更多
Dear Editor,Severe Acute Respiratory Syndrome Coronavirus Type 2(SARS-CoV-2) is the pathogen of the coronavirus disease 2019(COVID-19), which has spread worldwide.SARS-CoV-2 is an enveloped virus belongs to the family...Dear Editor,Severe Acute Respiratory Syndrome Coronavirus Type 2(SARS-CoV-2) is the pathogen of the coronavirus disease 2019(COVID-19), which has spread worldwide.SARS-CoV-2 is an enveloped virus belongs to the family of β-coronavirus(Xu et al., 2020). Its genome is a linear single-stranded positive-sense RNA about 30,000 nucleotides packed inside a virion with a diameter of 100 nm and a volume of about 10^(6)nm^(3)(Bar-On et al., 2020).展开更多
Room-temperature thermoelectric materials provide promising solutions for energy harvesting from the environment,and deliver a maintenance-free power supply for the internet-of-things(IoTs).The currently available Bi_...Room-temperature thermoelectric materials provide promising solutions for energy harvesting from the environment,and deliver a maintenance-free power supply for the internet-of-things(IoTs).The currently available Bi_(2)Te_(3) family discovered in the 1950s,still dominates industrial applications,however,it has serious disadvantages of brittleness and the resource shortage of tellurium(1×10^(-3) ppm in the earth's crust).The novel Mg_(3)Sb_(2) family has received increasing attention as a promising alternative for room-temperature thermoelectric materials.In this review,the development timeline and fabrication strategies of the Mg 3 Sb 2 family are depicted.Moreover,an insightful comparison between the crystal-linity and band structures of Mg_(3)Sb_(2) and Bi_(2)Te_(3) is drawn.An outlook is presented to discuss challenges and new paradigms in designing room-temperature thermoelectric materials.展开更多
(K,Na)NbO_(3)(KNN)-based lead-free piezoceramics have been the spotlight in search for practically viable candidates to replace the hazardous but dominating lead-containing counterparts.In this work,BaTiO_(3)(BT)modif...(K,Na)NbO_(3)(KNN)-based lead-free piezoceramics have been the spotlight in search for practically viable candidates to replace the hazardous but dominating lead-containing counterparts.In this work,BaTiO_(3)(BT)modified KNN ceramics were fabricated by spark plasma sintering(SPS)and the influence of BT content as well as sintering temperature on the phase structure,microstructure,and electrical properties were investigated.It was found that the 0.96(Na_(0.5)K_(0.5))NbO_(3)-0.04BaTiO_(3)(BT4)ceramics sintered at 1000℃have the optimal performance.Additionally,in-depth analysis of the electrical hysteresis revealed that the internal bias field originating from accumulation of space charges at grain boundaries is responsible for the asymmetry in the hysteresis loops.展开更多
Extremely low lattice thermal conductivity is always the pursuit of thermoelectric materials research.In this work,we reported an exceptional effect of Ag2S addition in MnTe,an emerging promising midtemperature thermo...Extremely low lattice thermal conductivity is always the pursuit of thermoelectric materials research.In this work,we reported an exceptional effect of Ag2S addition in MnTe,an emerging promising midtemperature thermoelectric material,to enable the realization of minimum lattice thermal conductivity,namely-0.4 Wm^(-1) K^(-1).Such a low lattice thermal conductivity is guaranteed by the incorporation of in-situ formed Ag rich phase(Ag2Te)with ultralow lattice thermal conductivity and further scattering of phonons from the partial doping effects induced point defects and boundaries between various phases.Apart from the dramatically decreased lattice thermal conductivity,the partial doping of Ag and S simultaneously enhance the electrical conductivity,further contributing to enhanced thermoelectric performance.Meanwhile,an inverse sign of Seebeck and Hall coefficient was observed and rationalized by the influence of highly electron-conductive Ag_(2)Te phase.Thanks to the synergetic modulation of electrical and thermal transport properties by in-situ formed composite,a high ZT value of 1.1 was achieved in MnTe based thermoelectric materials,which also demonstrates the importance of compositing approaches to design state-of-the-art thermoelectric materials.展开更多
文摘Objective:To observe the effects of pidotimod combined with ribavirin on inflammatory factors, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin in children with hand-foot-mouth disease.Methods: A total of 108 children with foot-hand-and-mouth epidemic in our hospital from Jan. 2013-Dec. 2016 were divide into the observation group and the control group, each groups has 54 cases. Two groups of children were treated with isolation, the observation group was given pidotimod combined with ribavirin, and the control group was treated with ribavirin. 5 mL venous blood of two group patients were collected at admission and after 6 d treatment, respectively, to compare inflammatory factor, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin in two groups.Results: Before treatment, the levels of inflammatory factor, T lymphocyte subsets, immunoglobulin, lactate, D-dimer and procalcitonin of two groups were not statistically significant. Compared with groups after treatment, the levels of CRP, IL-6, TNF-α were lower than that before treatment, CRP (2.23±0.37) mg/L, IL-6 (21.24±9.81) pg/mL and TNF-α (56.97±50.36) pg/mL levels in observation group after treatment were significantly lower than those in control group, the difference was statistically significant. After treatment, the levels of CD3, CD4, CD4/CD8, IgG, IgA and IgM in control group were significantly higher than that before treatment, the difference was statistically significant;After treatment, the levels of CD3 (51.26±10.27)%, CD4 (36.36±4.09)% and CD4/CD8 (1.60±0.47), IgG (10.24±1.82) mg/L, IgA (1.30±0.31) mg/L and IgM (1.48±0.30) mg/L in observation group were significantly higher than in control group, the difference was statistically significant. After treatment, the levels of lactate, D-dimer and procalcitonin in two groups were significantly lower than that before treatment, the difference was statistically significant;After treatment, the levels of lactate (1.19±0.20) mmol/L, D-dimer (150.23±27.21) ng/mL, and procalcitonin (0.08±0.02) ng/mL in observation group were significantly higher than in control group, the difference was statistically significant. Conclusion: Pidotimod combined with ribavirin has a pronounced effect on children with hand-foot-mouth disease, which can effectively reduce the body's inflammatory response, enhance immune function, improve clinical biochemical indicators, and should be widely recommended for clinical use.
基金Supported by the Hubei Province Health and Family Planning A Scientific Research Project,No.WJ2017M220the Wuhan Health Bureau Scientific Research Fund,No.WX19C11+2 种基金the Joint Precision Medical Research Fund From Taihe Hospital,No.2016JZ10the Shiyan COVID-19 Pilot Emergency Scientific Research Project,No.20Y19the Wuhan Children's Hospital Research Project,No.2017FE007.
文摘BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following the introduction of EV-A71 vaccines in China since 2016,the situation could change.CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China.However,the epidemiological characteristics of central China remain unknown.AIM To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City,central China,in recent years.METHODS The epidemiological,clinical,and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed.196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020.To detect and genotype enteroviruses,real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used.In Shiyan,168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes.Based on the logistic regression model,the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan.RESULTS From 2016 to 2020,35840 HFMD cases were reported in Shiyan.The number of cases decreased by 48.4%from 2016 to 2017.Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year,respectively.In 2020,a decrease of about 85.5%was reported when compared to 2019.The most common serotypes shifted from EV-A71 and CV-A16(about 60%-80%in 2016 and 2018)to others(more than 80.0%in 2017,2019,and 2020).EV-A71 lost its dominance in 2017 in Shiyan.Among 196 confirmed HFMD cases,85.7%tested positive for enterovirus,with CV-A6 being the most common serotype(121/168,72.0%).The positive rates for CV-A16 and CVA10 were 4.8%and 3.0%,respectively.There was no EV-A71 discovered.Infection with CV-A6 was linked to fever,myocardial damage,increased creatine kinase MB isoenzyme,and lactate dehydrogenase levels.CONCLUSION CV-A6 was the most common enterovirus serotype in Shiyan City,replacing EV-A71 and CV-A16 as the HFMD pathogen.Developing vaccines against CV-A6 or multiple pathogens,as well as rising CV-A6 surveillance,will help prevent HFMD in central China.
基金supported by National Natural Science Foundation of China(NSFC)under Grants No.52073155 and No.52150092the National Key Basic Research Program of China under Grant No.2020YFA0309100,and by the Project for Introduced Innovation Team in Jinan(2020GXRC037).
文摘Understanding the mechanisms and spatial correlations of crystallographic symmetry breaking in ferroelectric materials is essential to tuning their functional properties.While optical second harmonic generation(SHG)has long been utilized in ferroelectric studies,its capability for probing complex polar materials has yet to be fully realized.Here,we develop a SHG spectral imaging method implemented on a home-designed laser-scanning SHG microscope,and demonstrate its application for a model system of(K,Na)NbO3 single crystals.Supervised model fitting analysis produces comprehensive information about the polarization vector orientations and relative fractions of constituent domain variants as well as their thermal evolution across the polymorphic phase transitions.Multiple domains and phases are clearly delineated at different temperatures,suggesting the phase competitions in(K,Na)NbO3.Besides,we show that unsupervised matrix decomposition analysis can quickly and faithfully reveal domain configurations without a priori knowledge about specific material systems.The SHG spectral imaging method can be readily extended to other ferroelectric materials with potentials to be further enhanced.
基金This work was supported by the National Natural Science Foundation of China(52072028 and 52032007).
文摘NaNbO_(3)-based ceramics usually show ferroelectric-like P-E loops at room temperature due to the irreversible transformation of the antiferroelectric orthorhombic phase to ferroelectric orthorhombic phase,which is not conducive to energy storage applications.Our previous work found that incorporating CaHfO_(3) into NaNbO_(3) can stabilize its antiferroelectric phase by reducing the tolerance factor(t),as indicated by the appearance of characteristic double P-E loops.Furthermore,a small amount of MnO_(2) addition effectively regulate the phase structure and tolerance factor of 0.94NaNbO_(3)-0.06CaHfO_(3)(0.94NN-0.06CH),which can further improve the stability of antiferroelectricity.The XRD and XPS results reveal that the Mn ions preferentially replace A-sites and then B-sites as increasing MnO_(2).The antiferroelectric orthorhombic phase first increases and then decreases,while the t shows the reversed trend,thus an enhanced antiferroelectricity and the energy storage density Wrec of 1.69 J/cm^(3) at 240 kV/cm are obtained for 0.94NN-0.06CH-0.5%MnO_(2)(in mass fraction).With the increase of Mn content to 1.0%from 0.5%,the efficiency increases to 81% from 45%,although the energy storage density decreases to 1.31 J/cm^(3) due to both increased tolerance factor and non-polar phase.
基金supported by the National Natural Science Foundation of China (Nos.52002051 and 62074025)the Fundamental Research Funds for the Central Universities (No.ZYGX2020J009)the Applied Basic Research Program of Sichuan Province (No.2021JDGD0026).
文摘There has been a surge of research interest in the promising lead-free potassium-sodium niobate(KNN)-based ceramics,applications of which could be significantly promoted by improving thermal stability of piezoelectricity.Besides,endowing the KNN-based ceramics with photoluminescence property by rare-earth-ion doping can make them more completive lead-free counterparts in potential applications such as novel multifunctional sensing devices.Herein,a novel KNN-based ceramic material doped with Eu was elaborately designed to simultaneously obtain enhanced temperaturestable piezoelectricity and good luminescence property.By the introduction of diffused phase transition and the modulation of unit cell distortion,a large piezoelectric strain coefficient(d^(*)_(33))with a small variation(590±59 pm/V)over a wide temperature range(from room temperature to 110℃)was realized.The optimal composition also exhibited a considerable piezoelectric coefficient(d_(33))with small fluctuation(330±33 pC/N)from 20 to 80℃.In addition to the enhanced temperature-stable piezoelectricity,the luminescence of these ceramics was slightly enhanced with the elevation of BaZrO_(3)(BZ)doping contents,which could be attributed to the increased compositional disorder and the decreased unit cell distortion of the matrix material.Moreover,an optical characteristic was more prominent at ultra-low temperatures.This work unprecedentedly provides a novel paradigm for the design of multifunctional KNN-based ceramics with enhanced temperature-stable piezoelectricity and good luminescence property,revealing the great potential of the rare-earth-element-doped KNN material for future applications in the novel multifunctional devices.
基金supported by the National Natural Science Foundation of China(51402196,52072218,52192613)the National Key Research and Development Program of China(2021YFB3601504)the Natural Science Foundation of Shandong Province(ZR2022YQ43).
文摘Tunable devices constructed by ferroelectric thin flms are often desired to possess a low dielectric loss while maintainging a high dielectric tunability over a broad operating temperature range in applications,for example,resonators,filters,or phase shifters.However,it is dificult to simultaneously achieve these characteristics by traditional strategies,such as doping and strain modifying.Here,we demonstrate that the dielectric tunability of the sol-gel-prepared Pb(Sc_(1/2)Nb_(1/2))_(0.9)(Mg_(1/3)Nb_(2/3))_(0.O3)(PSNMN)thin film can be almost doubled from~47%to~80.0%(at 10kHz)at a low electric field(~530kV/cm),and the dielectric loss can be sharply reduced by more than an order of magnitude,from~0.50 to~0.037(at 1 kHz)when the thin flm was annealed in air at 650℃ for 15h under the help of an atmosphere-compensating-block(ACB)made from the proto-PSNMN gel.Moreover,the PSNMN thin flm annealed with ACB also exhibited an extremely high thermally-stable dielectric tunability in an ultrabroad temperature range(>130 K),which could be attributed to the Maxwell-Wagner(MW)effect generated by the interface between the PSNMN disordered matrix and the B-site nanoscale-ordered structure formed during the long-term annealing process.The reduced dielectric loss is mainly benefited from the reduced concentration of oxygen vacancy and the possibie MW efects,and the enhanced dielectric tunability could be ascribed to the weaker domain-pinning effect by oxygen vacancy.The breakthrough provides a new universal strategy to achieve utrahigh tunable performance in A(B'_(1/2)B"_(1/2))O3 ferroelectric thin films with a B-site nanoscale-ordered structure,meanwhile it paves the way for ultraintergrated tunable thin-flm-devices with great phase shifter performance in practical applications.
基金Tsinghua University Initiative Scientific Research Program and National Nature Science Foundation of China(Grant Nos.50921061 and 51028202).
文摘Most widely used piezoelectric ceramics are based on Pb(Zr,Ti)O3(PZT)composition which has adverse environmental and health effects due to its high lead content.Environmental and safety concerns with respect to the utilization,recycling,and disposal of lead-based piezoelectric ceramics have induced a new surge in developing lead-free piezoelectric ceramics.Among all the lead-free ceramics,(K,Na)NbO3(KNN)has drawn increasing attention because of its well-balanced piezoelectric properties and better environmental compatibility.On basis of the author’s work,this review summarizes the progress that has been made in recent years on development of KNN-based piezoelectric ceramics,including crystallographic structure and phase transition analysis,pressurized solid-state sintering as well as liquid-phase-assisted sintering process,and poling treatment for property enhancement.All in all,KNN is a promising lead-free system,but more research is still required both from academic and industrial interests.
基金supported by the National Natural Science Foundation of China(No.21875048)Guangdong Natural ScienceFoundation(No.2017A030313255)+3 种基金Major Scientific Project of Guangdong University(No.2017KZDXM059)Yangcheng Scholars Research Project of Guangzhou(No.201831820)Science and Technology Research Project of Guangzhou(No.201804010047)Guangzhou University’s 2017 Training Program for Young TopNotch Personnel(No.BJ201704)。
文摘CuWO4,as an n-type oxide semiconductor with a bandgap of 2.2 eV,has stimulated enormous interest as a potential broad-spectrum-active photocatalyst for environmental pollution remediations.However,rapid charge recombination greatly hinders its practical applications.Herein,we present a cascaded electron transition pathway in a ternary heterostructure consisting of CdS quantum dots,carbon dots(CDs)and CuWO4 hollow spheres,which proves to greatly facilitate the photogenerated electron-hole separation,and eventually boosts the degradation efficiency of phenol and congo red by 100%and 46%compared to bare CuWO4.The enhanced performance of the CuWO4/CdS/CDs heterostructure mainly originates from the unidirectional electron migration from CdS to CuWO4 and then to the organics through CDs.This work elucidates the electron transfer kinetics in multi-phase system and provides a new design paradigm for optimizing the properties of CuWO4 based photocatalysts.
基金the Basic Science Center Project of NSFC(Grant No.51788104)the National Natural Science Foundation(No.11474176)as well as the Shenzhen Science and Technology Plan Project(No.JCYJ20150827165038323).
文摘Developing high-efficiency materials with earth-abundant and low-toxicity elements has become a popular trend in the field of thermoelectrics.Among these compounds,oxides and sulfides,the lighter,cheaper and green analogies of tellurides,have been extensively investigated and summarized as well defined classes.Nonetheless,the vast family of selenides with better electrical performance,lower thermal conductivity and higher thermoelectric efficiency have not been specially discussed.Here in this review,we present recent advances in binary and multinary selenide thermoelectric materials,covering traditional PbSe,liquid-like Cu_(2)Se,layered SnSe,diamond-like and disordered multinary compounds.The features of selenides are discussed based on both environmental concerns and from the perspective of chemical bonding,transport properties and performance.Emphasis is put on the“compositionstructure-processing-performance”relationship,and some interesting issues are addressed.Finally,challenges for thermoelectric selenides are discussed,and possible optimization strategies are also suggested.
基金This work was supported by Science Challenge Project(No.TZ2018003)National Natural Science Foundation of China(Grant Nos.51822206 and 5171101344).
文摘Polarization switching in lead-free(K0.40Na0.60)NbO3(KNN)single crystals was studied by switching spectroscopy piezoresponse force microscopy(SS-PFM).Acquisition of multiple hysteresis loops on a closely spaced square grid enables polarization switching parameters to be mapped in real space.Piezoresponse amplitude and phase hysteresis loops show collective symmetric/asymmetric characteristics,affording information regarding the switching behavior of different domains.As such,the out-of-plane polarization states of the domains,including amplitudes and phases can be determined.Our results could contribute to a further understanding of the relationships between polarization switching and polarization vectors at the nanoscale,and provide a feasible method to correlate the polarization hysteresis loops in a domain under an electric field with the polarization vector states.
基金This work was supported by the Basic Science Center Project of NSFC under Grant No.51788104the National Key R&D Program of China(Grant No.2018YFB0703603).
文摘Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals;in particular,a higher out-of-plane ZT value could be achieved in ntype SnSe due to its 3D charge and 2D phonon transports.In this work,the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural microstructure.The textures were fabricated using mechanical alloying and repeated spark plasma sintering(SPS),as a kind of hot pressing,aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline SnSe.Results show that the lowest thermal conductivity of 0.36 Wm^(-1) K^(-1) was obtained at 783 K in perpendicular to texture direction.Interestingly,the electrical transport properties are less anisotropic and even nearly isotropic,and the power factors reach 681.3μWm^(-1) K^(-2) at 783 K along both parallel and perpendicular directions.The combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 K.The high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe,and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.
基金supported by the Basic Science Center Project of Natural Science Foundation of China(51788104)the National Key R&D Program of China(2018YFB0703603).
文摘Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric material.However,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS polycrystals.This work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier mobility.As a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S sample.Interestingly,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS sample.Moreover,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.
基金supported by the National Key R&D Program of China (2018YFB0703603)the Basic Science Center Project of National Natural Science Foundation of China (NSFC, 51788104)the NSFC (11474176)
基金Project supported by the National Key R&D Program of China(No.2017YFB0603701)the Key Program of the National Natural Science Foundation of China(No.51636007)partly supported by theèih China Aerodynamics Research and Development Center
基金This work was supported by the National Nature Science Foundation of China(Grants no.51332002,11374174,51390471,51527803 and 51221291)the Ministry of Science and Technology of China under Grant 2015CB654605,National 973 Project of China(2015CB654902)+1 种基金National key research and development program(2016YFB0700402)This work made use of the resources of the National Center for Electron Microscopy in Beijing and the BL14B1 beamline of the Shanghai Synchrotron Radiation Facility under project no.14SRBL14B10499.
文摘BiFeO_(3),a room-temperature multiferroic material,has recently been increasingly applied as a potential lead-free piezoelectric material due to its large piezoelectricity achieved by doping.In this work,12%Smdoped BiFeO_(3)epitaxial thin films were fabricated on Nb-doped SrTiO_(3)(001)single crystal substrates via sol-gel method.The epitaxy was verified by reciprocal space mapping(RSM)and transmission electron microscope(TEM).The TEM results indicated the coexistence of R3c and Pbam phases in the film.The domains and piezoelectric properties from room temperature to 200℃were characterized by piezoresponse force microscopy(PFM).Domains became active from 110℃to 170℃,and domain configurations changed obviously.A partially fading piezoresponse indicated the emergence of antiferroelectric Pbam.The in-situ domain analysis suggested that the phase transition was accompanied by domain wall motion.Switching spectroscopy PFM(SS-PFM)was further conducted to investigate the piezoresponse during the phase transition.Anomalous responses were found in both ON and OFF states at 170℃,and the film exhibits typical antiferroelectric behavior at 200℃,implying that the completion of phase transition and structure turned to the Pbam phase.This work revealed the origin of the high piezoresponse of Sm-doped BiFeO_(3)thin films at the morphotropic phase boundary(MPB).
基金Basic Science Center Project of NSFC,Grant/Award Number:51788104National Key R&D Program of China,Grant/Award Number:2018YFB0703603。
文摘Isobaric specific heat capacity(Cp)is an important parameter not only in physics but also for most materials.Its accurate measurement is particularly critical for performance evaluation of thermoelectric materials,but the experiments by differential scanning calorimetry(DSC)often lead to large uncertainties in the measurements,especially at elevated temperatures.In this study,we propose a simple method to determine Cp by measuring the sound velocity(υ)based on lattice vibration and expansion theory.The relative standard error of theυis smaller than 1%,showing good accuracy and repeatability.The calculated Cp at elevated temperature(>300 K)increases slightly with increasing temperature due to the lattice expansion,which is more reasonable than the Dulong–Petit value.
基金supported by grants from MOST(2018YFA0507201 to CL)from the National Natural Science Foundation of China(32070147 to CL)from Guangzhou Key Medical Discipline Construction Project
文摘Dear Editor,Severe Acute Respiratory Syndrome Coronavirus Type 2(SARS-CoV-2) is the pathogen of the coronavirus disease 2019(COVID-19), which has spread worldwide.SARS-CoV-2 is an enveloped virus belongs to the family of β-coronavirus(Xu et al., 2020). Its genome is a linear single-stranded positive-sense RNA about 30,000 nucleotides packed inside a virion with a diameter of 100 nm and a volume of about 10^(6)nm^(3)(Bar-On et al., 2020).
基金This work was supported by the Natural Science Foundation of China(grant number 51872133)National Key Research and Development Program of China(grant number 2019YFA0704900,2018YFB0703600)the Tencent Foundation through the XPLORER PRIZE and Shenzhen DRC project(grant number[2018]1433).
文摘Room-temperature thermoelectric materials provide promising solutions for energy harvesting from the environment,and deliver a maintenance-free power supply for the internet-of-things(IoTs).The currently available Bi_(2)Te_(3) family discovered in the 1950s,still dominates industrial applications,however,it has serious disadvantages of brittleness and the resource shortage of tellurium(1×10^(-3) ppm in the earth's crust).The novel Mg_(3)Sb_(2) family has received increasing attention as a promising alternative for room-temperature thermoelectric materials.In this review,the development timeline and fabrication strategies of the Mg 3 Sb 2 family are depicted.Moreover,an insightful comparison between the crystal-linity and band structures of Mg_(3)Sb_(2) and Bi_(2)Te_(3) is drawn.An outlook is presented to discuss challenges and new paradigms in designing room-temperature thermoelectric materials.
基金National Nature Science Foundation of China(Grants No.51572143,51302144,51332002)the Specialized Research Fund for the Doctoral Program of Higher Education(Grant No.20130002120031)the Tsinghua University Initiative Scientific Research Program(Grant No.20131089230).
文摘(K,Na)NbO_(3)(KNN)-based lead-free piezoceramics have been the spotlight in search for practically viable candidates to replace the hazardous but dominating lead-containing counterparts.In this work,BaTiO_(3)(BT)modified KNN ceramics were fabricated by spark plasma sintering(SPS)and the influence of BT content as well as sintering temperature on the phase structure,microstructure,and electrical properties were investigated.It was found that the 0.96(Na_(0.5)K_(0.5))NbO_(3)-0.04BaTiO_(3)(BT4)ceramics sintered at 1000℃have the optimal performance.Additionally,in-depth analysis of the electrical hysteresis revealed that the internal bias field originating from accumulation of space charges at grain boundaries is responsible for the asymmetry in the hysteresis loops.
基金supported by the National Key R&D Program of China(No.2018YFB0703603)。
文摘Extremely low lattice thermal conductivity is always the pursuit of thermoelectric materials research.In this work,we reported an exceptional effect of Ag2S addition in MnTe,an emerging promising midtemperature thermoelectric material,to enable the realization of minimum lattice thermal conductivity,namely-0.4 Wm^(-1) K^(-1).Such a low lattice thermal conductivity is guaranteed by the incorporation of in-situ formed Ag rich phase(Ag2Te)with ultralow lattice thermal conductivity and further scattering of phonons from the partial doping effects induced point defects and boundaries between various phases.Apart from the dramatically decreased lattice thermal conductivity,the partial doping of Ag and S simultaneously enhance the electrical conductivity,further contributing to enhanced thermoelectric performance.Meanwhile,an inverse sign of Seebeck and Hall coefficient was observed and rationalized by the influence of highly electron-conductive Ag_(2)Te phase.Thanks to the synergetic modulation of electrical and thermal transport properties by in-situ formed composite,a high ZT value of 1.1 was achieved in MnTe based thermoelectric materials,which also demonstrates the importance of compositing approaches to design state-of-the-art thermoelectric materials.