The accurate and efficient measurement of small molecule disease markers for clinical diagnosis is of great importance.In this study,a quadrupole-linear ion trap(Q-LIT)tandem mass spectrometer was designed and built i...The accurate and efficient measurement of small molecule disease markers for clinical diagnosis is of great importance.In this study,a quadrupole-linear ion trap(Q-LIT)tandem mass spectrometer was designed and built in our laboratory.Target precursor ions were first selected in the quadrupole,and then injected,trapped,and fragmented simultaneously in the linear ion trap(LIT)to reduce the space charge effect,enrich the target product ions,and promote sensitivity.The targeted analytes were measured with selected reaction monitoring using a positive scan mode with electrospray ionization(ESI).Ions with a mass-to-charge ratio(m/z)ranging from 195 to 2022 were demonstrated.When scanning at 1218amu.s^(-1),unit resolution and an accuracy of higher than m/z 0.28 was obtained for m/z up to 2000.The dimensionless Mathieu parameter(q)value used in this study was 0.40 for collision-induced dissociation(CID),which was activated by resonance excitation.And an overall CID efficiency of 64%was achieved(activation time,50 ms).Guanidinoacetic acid(GAA)and creatine(CRE)were used as model compounds for small molecule clinical biomarkers.The limits of quantification were 1.0 and 0.2 nmol.L^(-1)for GAA and CRE,respectively.A total of 77 actual samples were successfully analyzed by the home-built ESI-Q-LIT tandem mass spectrometry system.The developed method can reduce matrix interference,minimize space charge effects,and avoid the chromatographic separation of complex samples to simplify the pretreatment process.This novel Q-LIT system is expected to be a good candidate for the determination of biomarkers in clinical diagnosis and therapeutics.展开更多
Regulating interlayer distance is a crucial factor in the development of two‐dimensional(2D)nanomaterials.A 2D metal‐free photocatalyst,such as graphitic carbon nitride(g‐C3N4),exhibits morphology‐and microstruct...Regulating interlayer distance is a crucial factor in the development of two‐dimensional(2D)nanomaterials.A 2D metal‐free photocatalyst,such as graphitic carbon nitride(g‐C3N4),exhibits morphology‐and microstructure‐dependent photocatalytic activity.Herein,we report a straightforward and facile route for the preparation of unique lamellar g‐C3N4,by co‐firing melamine and ammonium chloride via microwave‐assisted heating.Through the decomposition of NH4Cl,the evaporation of NH3 gas can effectively overcome van der Waals forces,expanding the interlayer distance of g‐C3N4,thereby creating a lamellar structure consisting of nanosheets.Compared with bulk g‐C3N4,the NH3‐derived lamellar g‐C3N4 exhibits a larger specific surface area and enhanced optical absorption capability,which increase photocatalytic hydrogen production because of the highly active structure,excellent utilization efficiency of photon energy,and low recombination efficiency of photogenerated charge carriers.This study provides a simple strategy for the regulation of the g‐C3N4 microstructure toward highly efficient photocatalytic applications.展开更多
We present a coherent population trapping clock system based on laser-cooled^(87)Rb atoms.The clock consists of a frequency-stabilized CPT interrogation laser and a cooling laser as well as a compact magneto-optical t...We present a coherent population trapping clock system based on laser-cooled^(87)Rb atoms.The clock consists of a frequency-stabilized CPT interrogation laser and a cooling laser as well as a compact magneto-optical trap,a highperformance microwave synthesizer,and a signal detection system.The resonance signal in the continuous wave regime exhibits an absorption contrast of~50%.In the Ramsey interrogation method,the linewidth of the central fringe is31.25 Hz.The system achieves fractional frequency stability of 2.4×10^(-11)/(√τ),which goes down to 1.8×10^(-13)at 20000 s.The results validate that cold atom interrogation can improve the long-term frequency stability of coherent population trapping clocks and holds the potential for developing compact/miniature cold atoms clocks.展开更多
Alternaria mycotoxins are of concern due to its adverse health effect, they affect various cereal crops and grain-based food along with modified forms that contribute to overall exposure. This study aimed to determine...Alternaria mycotoxins are of concern due to its adverse health effect, they affect various cereal crops and grain-based food along with modified forms that contribute to overall exposure. This study aimed to determine the frequency and level of exposure to Alternaria mycotoxins(tenuazonic acid, TeA;alternariol, AOH;alternariol monomethyl ether, AME;tentoxin, TEN;and altenuene, ALT) in human urine from Beijing adults. A total of 2212 urine samples were collected and analyzed for five mycotoxins using LC–ESI–MS/MS. More than98% of the samples had at least one Alternaria mycotoxin detected. Among the mycotoxins,AME had the highest detection rate(96.0%), followed by TeA(70.5%). The calculated average daily intake values of AME(12.5 ng/kg b.w.) was 5 times the TTC value(2.5 ng/kg b.w.) set by the EFSA, indicating the potential health risks associated with mycotoxins. Immediate attention and subsequent actions should be taken to identify the sources of mycotoxins and the corresponding exposure pathways to humans in the investigated regions.展开更多
Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and diffe...Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is challenging.We intended to quantitatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge heterogeneity.The CIs of antibodies were fractionated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three levels.First,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation status.Second,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were identified.Peptide mapping showed nonuniform deamidation and glycoform distribution among CIs.In total,10 N-glycoforms were detected by peptide mapping.Finally,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched glycopeptides.Qualitative and quantitative analyses demonstrated the dynamics of 24 N-glycoforms.The results revealed that sialic acid modification is a critical factor accounting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight analyses.This study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.展开更多
Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB magnets.In this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB ma...Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB magnets.In this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB magnets and the fracture mode were investigated.Results show that the bending strength of magnets is reduced by pickling and heat treatment and greatly recove rs after heavy rare earth element(Tb)grain boundary diffusion.The pickling and the heat treatment cause a slight decrease in microhardness.Compared with the recovery of the bending strength,the hardness decreases after the GBDP.The fracture mode of bended magnets changes from intergranular to transgranular.This study helps in further improving the mechanical and magnetic properties of sintered NdFeB magnets.展开更多
Atomic Doppler broadening thermometry（DBT） is potentially an accurate and practical approach for thermodynamic temperature measurement. However, previous reported atomic DBT had a long acquisition time and had only ...Atomic Doppler broadening thermometry（DBT） is potentially an accurate and practical approach for thermodynamic temperature measurement. However, previous reported atomic DBT had a long acquisition time and had only been proved at the triple point of water, 0°C, for the purpose of determination of the Boltzmann constant. This research implemented the cesium atomic DBT for fast room temperature measurement. The Cs133 D1(6 S1/2→ 6 p1/2 transition) line was measured by direct laser absorption spectroscopy, and the quantity of thermal-induced linewidth broadening was precisely retrieved by the Voigt profile fitting algorithm. The preliminary results showed the proposed approach had a 4 min single-scan acquisition time and 0.2% reproducibility. It is expected that the atomic DBT could be used as an accurate, chip-scale, and calibration-free temperature sensor and standard.展开更多
The strength of microwave(MW)electric field can be observed with high precision by using the standard electromagnetically induced transparency and Aulter–Towns(EIT-AT)technique,when its frequency is resonant or nearl...The strength of microwave(MW)electric field can be observed with high precision by using the standard electromagnetically induced transparency and Aulter–Towns(EIT-AT)technique,when its frequency is resonant or nearly-resonant with the Rydberg transition frequency.As the detuning of MW field increases,one of the transmission peaks(single peak)is easier to measure due to its increased amplitude.It can be found that the central symmetry point of the two transmission peaks f_(1/2)is only related to the detuning of MW field△_(MW)and central symmetry point f_(0)of resonant MW field,satisfying the relation f_(1/2)=△_(MW)/2+f_(0).Thus,we demonstrate a single transmission peak method that the MW E-field can be determined by interval between the position of single peak and f_(1/2).We use this method to measure continuous frequencies in a band from-200 MHz to 200 MHz of the MW field.The experimental results and theoretical analysis are presented to describe the effectiveness of this method.For 50 MHz<△_(MW)<200 MHz,this method solves the problem that the AT splitting cannot be measured by using the standard EIT-AT techniques or multiple atomic-level Rydberg atom schemes.展开更多
Si lattice-based linewidth,as the most used calibrator in the semiconductor industry,failed to meet the nanoscale demands of critical dimensions(CD).In 2018,the Si(220)lattice spacing was recommended as a secondary re...Si lattice-based linewidth,as the most used calibrator in the semiconductor industry,failed to meet the nanoscale demands of critical dimensions(CD).In 2018,the Si(220)lattice spacing was recommended as a secondary realization of the meter definition,however,Si lattices as nanoscale rulers can only be used in ultra-high vacuum(UHV)environments.For the first time,we designed two-dimensional(2D)supramolecular self-assembly monolayers(SAMs)as a new generation of nanoscale rulers using scanning tunneling microscopy(STM)technology in atmospheric environment.Three SAMs nanoscale rulers were selected among seven types of SAMs based on their self-assembly behaviors and thermodynamic stability.One of these SAMs nanoscale rulers was used to calibrate the sTM images through lattice perspective transformation method,and directly determine the lattice length along the nanoscale rulers'lattice direction without calibration,proving the feasibility of SAMs nanoscale rulers in nanometrology.The construction of SAMs nanoscale rulers was straightforward and manageable in the atmosphere,significantly lowering the complexity of producing nano precise measurement tools.Identifying the ideal SAMs for use as nanoscale rulers holds immense potential to significantly reduce the cost of calibration in chip industries.展开更多
Antiferroelectric materials with double hysteresis loops are attractive for energy storage applications,which are becoming increasingly important for power electronics nowadays.Among them,AgNbO_(3) based lead-free cer...Antiferroelectric materials with double hysteresis loops are attractive for energy storage applications,which are becoming increasingly important for power electronics nowadays.Among them,AgNbO_(3) based lead-free ceramics have attracted intensive interest as one of promising environmental-friendly candidates.However,most of the AgNbO_(3) based ceramics suffers from low dielectric breakdown strength(Eb).The limitation of low Eb is broken to some extent in this work.Here,AgNbO_(3) epitaxial films were fabricated by pulsed laser deposition,which possess high Eb of 624 kV/cm.The(001)AgNbO_(3) epitaxial film reveals typical antiferroelectric hysteresis loops when the applied electric fields are over 300 kV/cm.A recoverable energy density of 5.8 J/cm^(3) and an energy efficiency of 55.8%are obtained at 600 kV/cm,which demonstrates the great promise of the AgNbO_(3) film for energy storage applications.展开更多
Surface functionalization of piezoelectric greatly determines its piezo-catalytic activity and selectivity in that functional group affect specific reactants’surface adsorption and activation abilities.Herein,we prop...Surface functionalization of piezoelectric greatly determines its piezo-catalytic activity and selectivity in that functional group affect specific reactants’surface adsorption and activation abilities.Herein,we propose chemical functionalization on the surface of nano-scaled BaTiO_(3)piezoelectric via a one-pot hydrothermal process using polyethylene glycol as surfactant,and evaluate its piezo-catalytic activity and selectivity by degrading model antibiotic and dye reactants under ultrasonic vibrations.Acetate or/and oxalic unidentate ligands on the surface of BaTiO_(3)nanobelts can be formed by controlling precursor and hydrothermal parameters.Particularly,oxalic acid functionalized BaTiO_(3)nanobelts presented a high piezo-catalytic rate constant of 0.068 min^(-1)for Rhodamine B solution and maintained>87%degradation efficiency within 30 min under the condition of ultrasonic bath with 40 kHz and 100 W,which was mainly ascribed to piezo-sensitization effect.This work provides references for the preparation of chemical functionalized catalysts and also contributes to the development of novel catalysts for special applications.展开更多
The excellent adsorption and rapid separation capabilities of magnetic MOFs make them desirable pretreatment materials for solid substrates.In this study,magnetic ZIF-8(mZIF-8)was synthesized in situ by a one-step met...The excellent adsorption and rapid separation capabilities of magnetic MOFs make them desirable pretreatment materials for solid substrates.In this study,magnetic ZIF-8(mZIF-8)was synthesized in situ by a one-step method in the aqueous solution of magnetic beads.Isothermal adsorption verified that the maximum adsorption capacity of(011)crystal-exposed rhombic dodecahedral ZIF-8 for chloramphenicol was up to 128.31 mg/g(mZIF-8=67.18 mg/g).Kinetic adsorption revealed that the type of ZIF-8/mZIF-8 adsorption on chloramphenicol belongs to the pseudo-secondary adsorption kinetics of chemical monomolecular layers.Characterization by FTIR,XPS,and XRD revealed that mZIF-8 interacts with chloramphenicol mainly byπ-πelectron stacking,electrostatic attraction,and hydrogen bonding interaction.ELISA confirmed that chloramphenicol remained antigenically active after adsorption by mZIF-8.The adsorption and separation of chloramphenicol residues in chicken and egg were completed by mZIF-8 within 20 min.mZIF-8 can be used directly for elution-free ELISA after the adsorption of chloramphenicol.The limits of detection(IC10)of the mZIF-8+ELISA in chicken and eggs were 1.18 ng/mL and 0.64 ng/mL,respectively.mZIF-8 is expected to be used as a magnetic solid-phase extraction material for the rapid pretreatment of antibiotic residues in other complex solid matrices.展开更多
The site-specific N-glycosylation changes of human plasma immunoglobulin gamma molecules(IgGs)have been shown to modulate the immune response and could serve as potential biomarkers for the accurate diagnosis of vario...The site-specific N-glycosylation changes of human plasma immunoglobulin gamma molecules(IgGs)have been shown to modulate the immune response and could serve as potential biomarkers for the accurate diagnosis of various diseases.However,quantifying intact N-glycopeptides accurately in large-scale clinical samples remains a challenge,and the quantitative N-glycosylation of plasma IgGs in patients with chronic kidney diseases(CKDs)has not yet been studied.In this study,we present a novel integrated intact N-glycopeptide quantitative pipeline(termed GlycoQuant),which combines our recently developed mass spectrometry fragmentation method(EThcD-sceHCD)and an intact N-glycopeptide batch quantification software tool(the upgraded PANDA v.1.2.5).We purified and digested human plasma IgGs from 58 healthy controls(HCs),48 patients with membranous nephropathy(MN),and 35 patients with IgA nephropathy(IgAN)within an hour.Then,we analyzed the digested peptides without enrichment using EThcD-sceHCD-MS/MS,which provided higher spectral quality and greater identified depth.Using upgraded PANDA,we performed site-specific N-glycosylation quantification of IgGs.Several quantified intact N-glycopeptides not only distinguished CKDs from HCs,but also different types of CKD(MN and IgAN)and may serve as accurate diagnostic tools for renal tubular function.In addition,we proved the applicability of this pipeline to complex samples by reanalyzing the intact N-glycopeptides from cell,urine,plasma,and tissue samples that we had previously identified.We believe that this pipeline can be applied to large-scale clinical N-glycoproteomic studies,facilitating the discovery of novel glycosylated biomarkers.展开更多
Protein glycosylation is a critical post-translational modification that influences protein folding,localization,stability,and functional interactions by attaching glycans to specific sites.This process is crucial for...Protein glycosylation is a critical post-translational modification that influences protein folding,localization,stability,and functional interactions by attaching glycans to specific sites.This process is crucial for biological functions of glycoproteins,and aberrant glycosylation can lead to genetic disorders,immune system issues,and multi-organ pathologies.Recent advancements in glycoproteomic technologies have made the study of protein glycosylation a key focus for understanding the pathogenesis of kidney diseases.This review provides a comprehensive overview of protein glycosylation mechanisms,its biological roles,molecular pathways,and significant functions in renal physiology and pathology.It specifically highlights the dynamic changes and regulatory networks associated with aberrant glycosylation in kidney diseases such as immunoglobulin A nephropathy,diabetic kidney disease,autosomal dominant polycystic kidney disease,renal cell carcinoma,and acute kidney injury.It also evaluates the clinical applications of related technologies and biomarkers.Additionally,it discusses the challenges in developing glycosylation-targeted therapeutic strategies.Future research should focus on clarifying cell-specific glycosylation regulatory networks in the kidney,integrating glycobiology with multi-omics approaches,and improving precision diagnostics and treatment for kidney diseases.展开更多
Whispering gallery mode resonators(WGMRs)have proven their advantages in terms of sensitivity and precision in various sensing applications.However,when high precision is pursued,the WGMR demands a high-quality factor...Whispering gallery mode resonators(WGMRs)have proven their advantages in terms of sensitivity and precision in various sensing applications.However,when high precision is pursued,the WGMR demands a high-quality factor usually at the cost of its free spectral range(FSR)and corresponding measurement range.In this article,we propose a high-resolution and wide-range temperature sensor based on chip-scale WGMRs,which utilizes a Si_(3)N_(4)ring resonator as the sensing element and a Mg F_(2)-based microcomb as a broadband frequency reference.By measuring the beatnote signal of the WGM and microcomb,the ultra-high resolution of 58 micro-Kelvin(μK)was obtained.To ensure high resolution and broad range simultaneously,we propose an ambiguity-resolving method based on the gradient of feedback voltage and combine it with a frequency-locking technique.In a proof-of-concept experiment,a wide measurement range of 45 K was demonstrated.Our soliton comb-assisted temperature measurement method offers high-resolution and wide-range capabilities,with promising advancements in various sensing applications.展开更多
Over 40% of the coronavirus disease 2019(COVID-19)COVID-19 patients were asymptomatically infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and the immune responses of these asymptomatic individ...Over 40% of the coronavirus disease 2019(COVID-19)COVID-19 patients were asymptomatically infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and the immune responses of these asymptomatic individuals is a critical factor for developing the strategy to contain the COVID-19 pandemic.Here,we determined the viral dynamics and antibody responses among 143 asymptomatic individuals identified in a massive screening of more than 5 million people in eight districts of Wuhan in May 2020.Asymptomatic individuals were admitted to the government-designated centralized sites in accordance with policy.The incidence rate of asymptomatic infection is〜2.92/100,000.These individuals had low viral copy numbers(peaked at 315 copies/mL)and short-lived antibody responses with the estimated diminish time of 69 days.The antibody responses in individuals with persistent SARS-CoV-2 infection is much longer with the estimated diminish time of 257 days.These results imply that the immune responses in the asymptomatic individuals are not potent enough for preventing SARS-CoV-2 re-infection,which has recently been reported in recovered COVID-19 patients.This casts doubt on the efficacy of forming"herd-immunity"through natural SARS-CoV-2 infection and urges for the development of safe and effective vaccines.展开更多
The SARS-CoV-2 infection causes severe immune disruption.However,it is unclear if disrupted immune regulation still exists and pertains in recovered COVID-19 patients.In our study,we have characterized the immunephe n...The SARS-CoV-2 infection causes severe immune disruption.However,it is unclear if disrupted immune regulation still exists and pertains in recovered COVID-19 patients.In our study,we have characterized the immunephe no type of B cells from 15 recovered COVID-19 patients,and found that healthy controls and recovered patients had similar B-cell populations before and after BCR stimulation,but the frequencies of PBC in patients were significantly increased when compared to healthy controls before stimulation.However,the percentage of unswitched memory B cells was decreased in recovered patients but not changed in healthy controls upon BCR stimulation.Interestingly,we found that CD19 expression was significantly reduced in almost all the B-cell subsets in recovered patients.Moreover,the BCR signaling and early B-cell response were disrupted upon BCR stimulation.Mechanistically,we found that the reduced CD19 expression was caused by the dysregulation of cell metabolism.In conclusion,we found that SARS-CoV-2 infection causes immunodeficiency in recovered patients by downregulating CD19 expression in B cells via enhandng B-cell metabolism,which may provide a new intervention target to cure COVID-19.展开更多
AgNbO_(3) is an antiferroelectric (AFE) material with double hysteresis loop. Both the antiferroelectricityand ferroelectricity can be enhanced by doping. Herein, the ferroelectricity of AgNbO_(3) ceramics wasenhanced...AgNbO_(3) is an antiferroelectric (AFE) material with double hysteresis loop. Both the antiferroelectricityand ferroelectricity can be enhanced by doping. Herein, the ferroelectricity of AgNbO_(3) ceramics wasenhanced via K-doping and the phase diagram of the (Ag_(1-x)K_(x))NbO_(3) ceramics was upgraded. In details,(Ag_(1-x)K_(x))NbO_(3) ceramics are ferrielectric (FIE) M1 phase as x=5.00-5.50 mol% and ferroelectric (FE) Ophase as x=5.75-6.00 mol% before poling, and FE O phase as x=5.00-6.00 mol% after poling at roomtemperature. With increasing temperature, (Ag_(1-x)K_(x))NbO_(3) ceramics show the phase evolutions from FIEM1, AFE M2 to paraelectric (PE) T phase at x=5.00-5.50 mol% and from FE O, FE T to PE T phase at x=5.75-6.00 mol% before poling, and from FE O, FE T to PE T phase at x=5.00-6.00 mol% after poling.High d33 values of 180 pC/N and 285 pC/N are obtained at the FE O-FE T and FE T-PE T phase boundaries.This work sheds light on a novel and promising lead-free piezoelectric system.展开更多
基金financially supported by the National Key R&D Program of China(2018YFF0212503,2019YFF0216303,and 2016YFF0200502)the National Natural Science Foundation of China(21927812)the Research Project of the National Institute of Metrology(AKY1934)。
文摘The accurate and efficient measurement of small molecule disease markers for clinical diagnosis is of great importance.In this study,a quadrupole-linear ion trap(Q-LIT)tandem mass spectrometer was designed and built in our laboratory.Target precursor ions were first selected in the quadrupole,and then injected,trapped,and fragmented simultaneously in the linear ion trap(LIT)to reduce the space charge effect,enrich the target product ions,and promote sensitivity.The targeted analytes were measured with selected reaction monitoring using a positive scan mode with electrospray ionization(ESI).Ions with a mass-to-charge ratio(m/z)ranging from 195 to 2022 were demonstrated.When scanning at 1218amu.s^(-1),unit resolution and an accuracy of higher than m/z 0.28 was obtained for m/z up to 2000.The dimensionless Mathieu parameter(q)value used in this study was 0.40 for collision-induced dissociation(CID),which was activated by resonance excitation.And an overall CID efficiency of 64%was achieved(activation time,50 ms).Guanidinoacetic acid(GAA)and creatine(CRE)were used as model compounds for small molecule clinical biomarkers.The limits of quantification were 1.0 and 0.2 nmol.L^(-1)for GAA and CRE,respectively.A total of 77 actual samples were successfully analyzed by the home-built ESI-Q-LIT tandem mass spectrometry system.The developed method can reduce matrix interference,minimize space charge effects,and avoid the chromatographic separation of complex samples to simplify the pretreatment process.This novel Q-LIT system is expected to be a good candidate for the determination of biomarkers in clinical diagnosis and therapeutics.
文摘Regulating interlayer distance is a crucial factor in the development of two‐dimensional(2D)nanomaterials.A 2D metal‐free photocatalyst,such as graphitic carbon nitride(g‐C3N4),exhibits morphology‐and microstructure‐dependent photocatalytic activity.Herein,we report a straightforward and facile route for the preparation of unique lamellar g‐C3N4,by co‐firing melamine and ammonium chloride via microwave‐assisted heating.Through the decomposition of NH4Cl,the evaporation of NH3 gas can effectively overcome van der Waals forces,expanding the interlayer distance of g‐C3N4,thereby creating a lamellar structure consisting of nanosheets.Compared with bulk g‐C3N4,the NH3‐derived lamellar g‐C3N4 exhibits a larger specific surface area and enhanced optical absorption capability,which increase photocatalytic hydrogen production because of the highly active structure,excellent utilization efficiency of photon energy,and low recombination efficiency of photogenerated charge carriers.This study provides a simple strategy for the regulation of the g‐C3N4 microstructure toward highly efficient photocatalytic applications.
基金supported by the National Natural Science Foundation of China(Grant No.61975194)。
文摘We present a coherent population trapping clock system based on laser-cooled^(87)Rb atoms.The clock consists of a frequency-stabilized CPT interrogation laser and a cooling laser as well as a compact magneto-optical trap,a highperformance microwave synthesizer,and a signal detection system.The resonance signal in the continuous wave regime exhibits an absorption contrast of~50%.In the Ramsey interrogation method,the linewidth of the central fringe is31.25 Hz.The system achieves fractional frequency stability of 2.4×10^(-11)/(√τ),which goes down to 1.8×10^(-13)at 20000 s.The results validate that cold atom interrogation can improve the long-term frequency stability of coherent population trapping clocks and holds the potential for developing compact/miniature cold atoms clocks.
基金supported by the National Key Research and Development Program of China (Nos. 2017YFC1600500, 2019YFF0216303)the Research Special Found for Municipal Medical Public Welfare institute (No. 2017-BJYJ-15)the Research Project of the National Institute of Metrology (Nos. AKY1934, 31-AKYZZ2039)。
文摘Alternaria mycotoxins are of concern due to its adverse health effect, they affect various cereal crops and grain-based food along with modified forms that contribute to overall exposure. This study aimed to determine the frequency and level of exposure to Alternaria mycotoxins(tenuazonic acid, TeA;alternariol, AOH;alternariol monomethyl ether, AME;tentoxin, TEN;and altenuene, ALT) in human urine from Beijing adults. A total of 2212 urine samples were collected and analyzed for five mycotoxins using LC–ESI–MS/MS. More than98% of the samples had at least one Alternaria mycotoxin detected. Among the mycotoxins,AME had the highest detection rate(96.0%), followed by TeA(70.5%). The calculated average daily intake values of AME(12.5 ng/kg b.w.) was 5 times the TTC value(2.5 ng/kg b.w.) set by the EFSA, indicating the potential health risks associated with mycotoxins. Immediate attention and subsequent actions should be taken to identify the sources of mycotoxins and the corresponding exposure pathways to humans in the investigated regions.
基金the financial support from the National Key Program for Basic Research of China(Grant Nos.:2018YFC0910302 and 2017YFF0205400)the National Natural Science Foundation of China(Grant No.:81530021)Innovation Foundation of Medicine(Grant Nos.:BWS14J052 and 16CXZ027)
文摘Posttranslational modifications of antibody products affect their stability,charge distribution,and drug activity and are thus a critical quality attribute.The comprehensive mapping of antibody modifications and different charge isomers(CIs)is of utmost importance,but is challenging.We intended to quantitatively characterize the posttranslational modification status of CIs of antibody drugs and explore the impact of posttranslational modifications on charge heterogeneity.The CIs of antibodies were fractionated by strong cation exchange chromatography and verified by capillary isoelectric focusing-whole column imaging detection,followed by stepwise structural characterization at three levels.First,the differences between CIs were explored at the intact protein level using a top-down mass spectrometry approach;this showed differences in glycoforms and deamidation status.Second,at the peptide level,common modifications of oxidation,deamidation,and glycosylation were identified.Peptide mapping showed nonuniform deamidation and glycoform distribution among CIs.In total,10 N-glycoforms were detected by peptide mapping.Finally,an in-depth analysis of glycan variants of CIs was performed through the detection of enriched glycopeptides.Qualitative and quantitative analyses demonstrated the dynamics of 24 N-glycoforms.The results revealed that sialic acid modification is a critical factor accounting for charge heterogeneity,which is otherwise missed in peptide mapping and intact molecular weight analyses.This study demonstrated the importance of the comprehensive analyses of antibody CIs and provides a reference method for the quality control of biopharmaceutical analysis.
基金Project supported by the National Key Research and Development Program of China(2021YFB3502902)the Key Research and Development Program of Ningbo(2021Z024)。
文摘Grain boundary diffusion process(GBDP)is a widely used method of increasing the coercivity of sintered NdFeB magnets.In this study,the effects of the GBDP on the bending strength and microhardness of sintered NdFeB magnets and the fracture mode were investigated.Results show that the bending strength of magnets is reduced by pickling and heat treatment and greatly recove rs after heavy rare earth element(Tb)grain boundary diffusion.The pickling and the heat treatment cause a slight decrease in microhardness.Compared with the recovery of the bending strength,the hardness decreases after the GBDP.The fracture mode of bended magnets changes from intergranular to transgranular.This study helps in further improving the mechanical and magnetic properties of sintered NdFeB magnets.
基金supported by the National Key R&D Program of China(No.2017YFF0206102)
文摘Atomic Doppler broadening thermometry（DBT） is potentially an accurate and practical approach for thermodynamic temperature measurement. However, previous reported atomic DBT had a long acquisition time and had only been proved at the triple point of water, 0°C, for the purpose of determination of the Boltzmann constant. This research implemented the cesium atomic DBT for fast room temperature measurement. The Cs133 D1(6 S1/2→ 6 p1/2 transition) line was measured by direct laser absorption spectroscopy, and the quantity of thermal-induced linewidth broadening was precisely retrieved by the Voigt profile fitting algorithm. The preliminary results showed the proposed approach had a 4 min single-scan acquisition time and 0.2% reproducibility. It is expected that the atomic DBT could be used as an accurate, chip-scale, and calibration-free temperature sensor and standard.
基金Project supported by the National Key Research and Development Program of China(Grant No.2021YFF0603704)the National Natural Science Foundation of China(Grant No.62071443)。
文摘The strength of microwave(MW)electric field can be observed with high precision by using the standard electromagnetically induced transparency and Aulter–Towns(EIT-AT)technique,when its frequency is resonant or nearly-resonant with the Rydberg transition frequency.As the detuning of MW field increases,one of the transmission peaks(single peak)is easier to measure due to its increased amplitude.It can be found that the central symmetry point of the two transmission peaks f_(1/2)is only related to the detuning of MW field△_(MW)and central symmetry point f_(0)of resonant MW field,satisfying the relation f_(1/2)=△_(MW)/2+f_(0).Thus,we demonstrate a single transmission peak method that the MW E-field can be determined by interval between the position of single peak and f_(1/2).We use this method to measure continuous frequencies in a band from-200 MHz to 200 MHz of the MW field.The experimental results and theoretical analysis are presented to describe the effectiveness of this method.For 50 MHz<△_(MW)<200 MHz,this method solves the problem that the AT splitting cannot be measured by using the standard EIT-AT techniques or multiple atomic-level Rydberg atom schemes.
基金This work was supported by the National Key Research and Development Program of China(No.2021YFA1202801)the National Natural Science Foundation of China(No.22272039)+2 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)the AKYCX2309 fund of National Institute of Metrology ChinaJilin Chinese Academy of Sciences-Yanshen Technology Co.Ltd.
文摘Si lattice-based linewidth,as the most used calibrator in the semiconductor industry,failed to meet the nanoscale demands of critical dimensions(CD).In 2018,the Si(220)lattice spacing was recommended as a secondary realization of the meter definition,however,Si lattices as nanoscale rulers can only be used in ultra-high vacuum(UHV)environments.For the first time,we designed two-dimensional(2D)supramolecular self-assembly monolayers(SAMs)as a new generation of nanoscale rulers using scanning tunneling microscopy(STM)technology in atmospheric environment.Three SAMs nanoscale rulers were selected among seven types of SAMs based on their self-assembly behaviors and thermodynamic stability.One of these SAMs nanoscale rulers was used to calibrate the sTM images through lattice perspective transformation method,and directly determine the lattice length along the nanoscale rulers'lattice direction without calibration,proving the feasibility of SAMs nanoscale rulers in nanometrology.The construction of SAMs nanoscale rulers was straightforward and manageable in the atmosphere,significantly lowering the complexity of producing nano precise measurement tools.Identifying the ideal SAMs for use as nanoscale rulers holds immense potential to significantly reduce the cost of calibration in chip industries.
基金supported by the National Natural Science Foundation of China(No.51802068 and No.52073144)Advanced Talents Incubation Program of the Hebei University,China(No.801260201180)+2 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK20201301)the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(No.KF202005)the Basic Scientific Research Program of National Institute of Metrology(No.AKY1949).
文摘Antiferroelectric materials with double hysteresis loops are attractive for energy storage applications,which are becoming increasingly important for power electronics nowadays.Among them,AgNbO_(3) based lead-free ceramics have attracted intensive interest as one of promising environmental-friendly candidates.However,most of the AgNbO_(3) based ceramics suffers from low dielectric breakdown strength(Eb).The limitation of low Eb is broken to some extent in this work.Here,AgNbO_(3) epitaxial films were fabricated by pulsed laser deposition,which possess high Eb of 624 kV/cm.The(001)AgNbO_(3) epitaxial film reveals typical antiferroelectric hysteresis loops when the applied electric fields are over 300 kV/cm.A recoverable energy density of 5.8 J/cm^(3) and an energy efficiency of 55.8%are obtained at 600 kV/cm,which demonstrates the great promise of the AgNbO_(3) film for energy storage applications.
基金The authors appreciate funding from National College Students Innovation and Entrepreneurship Training Program of China(No.201910356015).
文摘Surface functionalization of piezoelectric greatly determines its piezo-catalytic activity and selectivity in that functional group affect specific reactants’surface adsorption and activation abilities.Herein,we propose chemical functionalization on the surface of nano-scaled BaTiO_(3)piezoelectric via a one-pot hydrothermal process using polyethylene glycol as surfactant,and evaluate its piezo-catalytic activity and selectivity by degrading model antibiotic and dye reactants under ultrasonic vibrations.Acetate or/and oxalic unidentate ligands on the surface of BaTiO_(3)nanobelts can be formed by controlling precursor and hydrothermal parameters.Particularly,oxalic acid functionalized BaTiO_(3)nanobelts presented a high piezo-catalytic rate constant of 0.068 min^(-1)for Rhodamine B solution and maintained>87%degradation efficiency within 30 min under the condition of ultrasonic bath with 40 kHz and 100 W,which was mainly ascribed to piezo-sensitization effect.This work provides references for the preparation of chemical functionalized catalysts and also contributes to the development of novel catalysts for special applications.
基金supported by the National Key Research and Development Program of China(No.2020YFF01014605).
文摘The excellent adsorption and rapid separation capabilities of magnetic MOFs make them desirable pretreatment materials for solid substrates.In this study,magnetic ZIF-8(mZIF-8)was synthesized in situ by a one-step method in the aqueous solution of magnetic beads.Isothermal adsorption verified that the maximum adsorption capacity of(011)crystal-exposed rhombic dodecahedral ZIF-8 for chloramphenicol was up to 128.31 mg/g(mZIF-8=67.18 mg/g).Kinetic adsorption revealed that the type of ZIF-8/mZIF-8 adsorption on chloramphenicol belongs to the pseudo-secondary adsorption kinetics of chemical monomolecular layers.Characterization by FTIR,XPS,and XRD revealed that mZIF-8 interacts with chloramphenicol mainly byπ-πelectron stacking,electrostatic attraction,and hydrogen bonding interaction.ELISA confirmed that chloramphenicol remained antigenically active after adsorption by mZIF-8.The adsorption and separation of chloramphenicol residues in chicken and egg were completed by mZIF-8 within 20 min.mZIF-8 can be used directly for elution-free ELISA after the adsorption of chloramphenicol.The limits of detection(IC10)of the mZIF-8+ELISA in chicken and eggs were 1.18 ng/mL and 0.64 ng/mL,respectively.mZIF-8 is expected to be used as a magnetic solid-phase extraction material for the rapid pretreatment of antibiotic residues in other complex solid matrices.
基金funded by Grants from the National Key Research and Development Program of China(2022YFF0608401,2022YFF0608404)National Natural Science Foundation of China(Grant number 31901038)+2 种基金Department of Science and Technology of Sichuan Province(2021YJ0479)CAMS Innovation Fund for Medical Sciences(2019-I2M-5-063)Research Project of the National Institute of Metrology(AKYZD2111).
文摘The site-specific N-glycosylation changes of human plasma immunoglobulin gamma molecules(IgGs)have been shown to modulate the immune response and could serve as potential biomarkers for the accurate diagnosis of various diseases.However,quantifying intact N-glycopeptides accurately in large-scale clinical samples remains a challenge,and the quantitative N-glycosylation of plasma IgGs in patients with chronic kidney diseases(CKDs)has not yet been studied.In this study,we present a novel integrated intact N-glycopeptide quantitative pipeline(termed GlycoQuant),which combines our recently developed mass spectrometry fragmentation method(EThcD-sceHCD)and an intact N-glycopeptide batch quantification software tool(the upgraded PANDA v.1.2.5).We purified and digested human plasma IgGs from 58 healthy controls(HCs),48 patients with membranous nephropathy(MN),and 35 patients with IgA nephropathy(IgAN)within an hour.Then,we analyzed the digested peptides without enrichment using EThcD-sceHCD-MS/MS,which provided higher spectral quality and greater identified depth.Using upgraded PANDA,we performed site-specific N-glycosylation quantification of IgGs.Several quantified intact N-glycopeptides not only distinguished CKDs from HCs,but also different types of CKD(MN and IgAN)and may serve as accurate diagnostic tools for renal tubular function.In addition,we proved the applicability of this pipeline to complex samples by reanalyzing the intact N-glycopeptides from cell,urine,plasma,and tissue samples that we had previously identified.We believe that this pipeline can be applied to large-scale clinical N-glycoproteomic studies,facilitating the discovery of novel glycosylated biomarkers.
基金supported by the National Key Research and Development Program of China(grant Nos.2022YFF0608401,2022YFF0608404,2021YFF0702003-02)the National Natural Science Foundation of China(grant No.92478101).
文摘Protein glycosylation is a critical post-translational modification that influences protein folding,localization,stability,and functional interactions by attaching glycans to specific sites.This process is crucial for biological functions of glycoproteins,and aberrant glycosylation can lead to genetic disorders,immune system issues,and multi-organ pathologies.Recent advancements in glycoproteomic technologies have made the study of protein glycosylation a key focus for understanding the pathogenesis of kidney diseases.This review provides a comprehensive overview of protein glycosylation mechanisms,its biological roles,molecular pathways,and significant functions in renal physiology and pathology.It specifically highlights the dynamic changes and regulatory networks associated with aberrant glycosylation in kidney diseases such as immunoglobulin A nephropathy,diabetic kidney disease,autosomal dominant polycystic kidney disease,renal cell carcinoma,and acute kidney injury.It also evaluates the clinical applications of related technologies and biomarkers.Additionally,it discusses the challenges in developing glycosylation-targeted therapeutic strategies.Future research should focus on clarifying cell-specific glycosylation regulatory networks in the kidney,integrating glycobiology with multi-omics approaches,and improving precision diagnostics and treatment for kidney diseases.
基金National Key Research and Development Program of China(2022YFF0608304)National Natural Science Foundation of China(62075206,62205324)。
文摘Whispering gallery mode resonators(WGMRs)have proven their advantages in terms of sensitivity and precision in various sensing applications.However,when high precision is pursued,the WGMR demands a high-quality factor usually at the cost of its free spectral range(FSR)and corresponding measurement range.In this article,we propose a high-resolution and wide-range temperature sensor based on chip-scale WGMRs,which utilizes a Si_(3)N_(4)ring resonator as the sensing element and a Mg F_(2)-based microcomb as a broadband frequency reference.By measuring the beatnote signal of the WGM and microcomb,the ultra-high resolution of 58 micro-Kelvin(μK)was obtained.To ensure high resolution and broad range simultaneously,we propose an ambiguity-resolving method based on the gradient of feedback voltage and combine it with a frequency-locking technique.In a proof-of-concept experiment,a wide measurement range of 45 K was demonstrated.Our soliton comb-assisted temperature measurement method offers high-resolution and wide-range capabilities,with promising advancements in various sensing applications.
基金supported by the National Science and Technology Major Project(No.2018ZX10101004001005)the National Key R&D Program of China(2018YFA0507201)+3 种基金the National Natural Science Foundation of China(No.31770188,32070179 and 31900144)Fundamental Research Funds for Central Public Welfare Scientific Research Institutes sponsored by National Institute of Metrology,P.R.China(grant no.31-ZYZJ2001 and grant no.AKYYJ2009)the Advanced Customer Cultivation Project of Wuhan National Biosafety Laboratory Chinese Academy of Sciences(No.2018ACCP-MS01)the Key Technology Development Program of Shenzhen(grant no.JSGG20200225153042494).
文摘Over 40% of the coronavirus disease 2019(COVID-19)COVID-19 patients were asymptomatically infected with severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)and the immune responses of these asymptomatic individuals is a critical factor for developing the strategy to contain the COVID-19 pandemic.Here,we determined the viral dynamics and antibody responses among 143 asymptomatic individuals identified in a massive screening of more than 5 million people in eight districts of Wuhan in May 2020.Asymptomatic individuals were admitted to the government-designated centralized sites in accordance with policy.The incidence rate of asymptomatic infection is〜2.92/100,000.These individuals had low viral copy numbers(peaked at 315 copies/mL)and short-lived antibody responses with the estimated diminish time of 69 days.The antibody responses in individuals with persistent SARS-CoV-2 infection is much longer with the estimated diminish time of 257 days.These results imply that the immune responses in the asymptomatic individuals are not potent enough for preventing SARS-CoV-2 re-infection,which has recently been reported in recovered COVID-19 patients.This casts doubt on the efficacy of forming"herd-immunity"through natural SARS-CoV-2 infection and urges for the development of safe and effective vaccines.
基金supported by the National Natural Science Foundation of China(31970839)the National Key R&D Program of China(1316203)+1 种基金Independent Innovation Research Fund of Huazhong University of Science and Technology(2020kfyXGYJ017)the HUST Academic Frontier Youth Team(2018QYTD10).
文摘The SARS-CoV-2 infection causes severe immune disruption.However,it is unclear if disrupted immune regulation still exists and pertains in recovered COVID-19 patients.In our study,we have characterized the immunephe no type of B cells from 15 recovered COVID-19 patients,and found that healthy controls and recovered patients had similar B-cell populations before and after BCR stimulation,but the frequencies of PBC in patients were significantly increased when compared to healthy controls before stimulation.However,the percentage of unswitched memory B cells was decreased in recovered patients but not changed in healthy controls upon BCR stimulation.Interestingly,we found that CD19 expression was significantly reduced in almost all the B-cell subsets in recovered patients.Moreover,the BCR signaling and early B-cell response were disrupted upon BCR stimulation.Mechanistically,we found that the reduced CD19 expression was caused by the dysregulation of cell metabolism.In conclusion,we found that SARS-CoV-2 infection causes immunodeficiency in recovered patients by downregulating CD19 expression in B cells via enhandng B-cell metabolism,which may provide a new intervention target to cure COVID-19.
基金This work was supported by the National Natural Science Foun-dation of China(No.51802068 and No.52073144)the Natural Sci-ence Foundation of Hebei Province,China(No.E2021201044)+4 种基金the Advanced Talents Incubation Program of the Hebei University,China(No.801260201180)the Natural Science Foundation of Jiangsu Province,China(No.BK20201301)the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(No.KF202005 and No.KF202114)China Postdoctoral Science Foun-dation(No.2021M692491)Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110251).
文摘AgNbO_(3) is an antiferroelectric (AFE) material with double hysteresis loop. Both the antiferroelectricityand ferroelectricity can be enhanced by doping. Herein, the ferroelectricity of AgNbO_(3) ceramics wasenhanced via K-doping and the phase diagram of the (Ag_(1-x)K_(x))NbO_(3) ceramics was upgraded. In details,(Ag_(1-x)K_(x))NbO_(3) ceramics are ferrielectric (FIE) M1 phase as x=5.00-5.50 mol% and ferroelectric (FE) Ophase as x=5.75-6.00 mol% before poling, and FE O phase as x=5.00-6.00 mol% after poling at roomtemperature. With increasing temperature, (Ag_(1-x)K_(x))NbO_(3) ceramics show the phase evolutions from FIEM1, AFE M2 to paraelectric (PE) T phase at x=5.00-5.50 mol% and from FE O, FE T to PE T phase at x=5.75-6.00 mol% before poling, and from FE O, FE T to PE T phase at x=5.00-6.00 mol% after poling.High d33 values of 180 pC/N and 285 pC/N are obtained at the FE O-FE T and FE T-PE T phase boundaries.This work sheds light on a novel and promising lead-free piezoelectric system.
