Conventional superconducting nanowire single-photon detectors(SNSPDs)have been typically limited in their applications due to their size,weight,and power consumption,which confine their use to laboratory settings.Howe...Conventional superconducting nanowire single-photon detectors(SNSPDs)have been typically limited in their applications due to their size,weight,and power consumption,which confine their use to laboratory settings.However,with the rapid development of remote imaging,sensing technologies,and long-range quantum communication with fewer topographical constraints,the demand for high-efficiency single-photon detectors integrated with avionic platforms is rapidly growing.We herein designed and manufactured the first drone-based SNSPD system with a system detection efficiency(SDE)as high as 91.8%.This drone-based system incorporates high-performance NbTiN SNSPDs,a self-developed miniature liquid helium dewar,and custom-built integrated electrical setups,making it capable of being launched in complex topographical conditions.Such a drone-based SNSPD system may open the use of SNSPDs for applications that demand high SDE in complex environments.展开更多
A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillaryelectrophoresis with high frequency conductivity detection (contactless conductivity detection) wasdescribed. The CSF sample was...A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillaryelectrophoresis with high frequency conductivity detection (contactless conductivity detection) wasdescribed. The CSF sample was pretreated with silver cation resin to remove high concentration ofCl- ions in CSF. The separation was achieved in the buffer solution of 10 mmol/L Tris and 8mmol/L boric acid at the separation voltage of 20.0 kV. Glu showed linear response in the range of5.0×10-6 to 6.0×10-3 mol/L, the limit of detection was 1.0×10-6 mol/L. The method was used foranalysis Glu in CSF satisfactorily with a recovery of 97.8-98.8%.展开更多
A novel analytical method was developed for determining morpholinium cations lacking ultraviolet absorption groups.This determination was carried out by high performance liquid chromatographyindirect ultraviolet（HPLC...A novel analytical method was developed for determining morpholinium cations lacking ultraviolet absorption groups.This determination was carried out by high performance liquid chromatographyindirect ultraviolet（HPLC-1UV） detection using imidazolium ionic liquid as background absorption reagents,and imidazolium ionic liquid aq.soln.-organic solvent as mobile phase by a reversed-phase C18 column.The background ultraviolet absorption reagents,imidazolium ionic liquids and organic solvents were investigated.The imidazolium ionic liquid in the mobile phase is not only the background ultraviolet absorption reagent for IUV,but also an active component to improve the separation of morpholinium cations.It was found that morpholinium cations could be adequately determined when0.5 mmol/L 1-ethyl-3-methylimidazolium tetrafluoroborate aq.soln./methanol（80：20,v/v） was used as mobile phase with an IUV detection wavelength of 210 nm.In this study,the baseline separation of Nmethyl,ethylmorpholinium cations（MEMo） and N-methyl.propylmorpholinium cations（MPMo） was successfully achieved in 8.5 min.The detection limits（S/N = 3） for MEMo and MPMo were 0.15 and0.29 mg/L,respectively.This simple and practical method has been successfully applied to the determination of two morpholinium ionic liquids synthesized by the chemistry laboratory.展开更多
Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for...Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.展开更多
As one of the most important tumor-associated antigens of colorectal adenocarcinoma, the carcinoembryonic antigen （CEA） threatens human health seriously ali over the globe. Fast electrical and highly sensitive detec...As one of the most important tumor-associated antigens of colorectal adenocarcinoma, the carcinoembryonic antigen （CEA） threatens human health seriously ali over the globe. Fast electrical and highly sensitive detection of the CEA with A1GaN/GaN high electron mobility transistor is demonstrated experimentally. To achieve a low detection limit, the Au-gated sensing area of the sensor is functionalized with a CEA aptamer instead of the corresponding antibody. The proposed aptasensor has successfully detected different concentrations （ranging from 50picogram/milliliter （pg/ml） to 50 nanogram/milliliter （ng/ml）） of CEA and achieved a detection limit as low as 50pg/ml at Vas = 0.5 V. The drain-source current shows a c/ear increase of 11.5μA under this bias.展开更多
Radioactive iodine gas detection has significant applications in the nuclear industry,particularly in nuclear accident scenarios and nuclear fuel reprocessing facilities.Herein,chemically stable metal-organic framewor...Radioactive iodine gas detection has significant applications in the nuclear industry,particularly in nuclear accident scenarios and nuclear fuel reprocessing facilities.Herein,chemically stable metal-organic frameworks(MOFs)with good affinity for iodine(including Zn(1,3-BDP),UiO-66,UiO-66-NH2,etc.)were computationally screened and drop-casted upon interdigitated electrodes(IDEs).These MOFs were used to develop advanced iodine sensors to achieve the direct electrical detection of I2 gas via impedance spectroscopy measurements.Upon exposure to I2 gas,a similar electrical response change has occurred for all the IDE sensors,despite in the different impedance ratio.In particular,UiO-66-coated sensors exhibited an impedance ratio>103 times,while the modification of amino groups(-NH2)enhanced the sensitivity,exceeding 104 times for UiO-66-NH2,and was accompanied by a better iodine uptake.Notably,the sensors fabricated from Zn(1,3-BDP),which also contained nitrogen atoms,exhibited excellent comprehensive sensing performance,including high sensitivity(with impedance ratio achieving 1.4×106 times),good recyclability,rapid response speed(with impedance change ratio of 250 times within 3 min),low detection limit(about 29 times under 300 ppm I2 vapor at 25°C),and high anti-interference ability.Our theoretical calculations revealed that the underlying I2 sensing mechanism could be attributed to a decreased band gap and enhanced electrical conductivity due to the new electronic states introduced by the adsorbed I2.This work proposes a novel and feasible method for investigating sensing materials and strategies to fabricate high-performance iodine gas sensors,providing a basis for developing nuclear radioactivity monitoring technology and emergency security safeguard equipment.展开更多
This study employs an N-carboxyanhydride ring-opening polymerization(NCA ROP)signal amplification strategy to construct a novel sensing system for the simple and rapid detection of tobacco mosaic virus RNA(tRNA).In th...This study employs an N-carboxyanhydride ring-opening polymerization(NCA ROP)signal amplification strategy to construct a novel sensing system for the simple and rapid detection of tobacco mosaic virus RNA(tRNA).In the developed fluorescent biosensor,carboxylated biomagnetic beads serve as carriers for target capture based on the complementary pairing of the aptamer bases.Subsequently,NCA ROP fluorescent peptides are utilized as highly biocompatible signal carriers to achieve sensitive detection of the target.Under the optimal conditions,the biosensor exhibits a broad linear detection range from 1 pM to 10 nM,with a detection limit as low as 0.085 pM.Furthermore,the fluorescent aptamer biosensor demonstrates robust affinity and reliability in recovery experiments involving healthy R ehmannia glutinosa leaf total RNA.This work establishes a robust platform for tRNA analysis,facilitating real-time and early diagnosis of various plant viruses.展开更多
With the significant progress of high-energy physics,nuclear science,and technology,the demand for high-performance scintillators is growing rapidly.Among solid-state scintillators,glass scintillators would play a vit...With the significant progress of high-energy physics,nuclear science,and technology,the demand for high-performance scintillators is growing rapidly.Among solid-state scintillators,glass scintillators would play a vital role in the field of high-energy radiation detections because of their merits including low cost,batch production,and arbitrariness in shape.In this review article,the research and development of glass scintillators is introduced with respect to the following key parameters including:density,light yield,scintillation decay time,and radiation hardness.The scintillation mechanisms,preparation methods particularly for Ce^(3+)-activated glasses,standard testing methods,scintillation performance,and applications of glass scintillators are comprehensively reviewed and critically discussed.Finally,the problems existing in the research field are presented and the future development directions of glass scintillators for performance improvement are suggested.展开更多
The precise neural mechanisms by which general anesthetics induce unconsciousness remain undetermined,with ongoing debate over whether they primarily affect the cortex directly or act predominantly on the sleep–wake ...The precise neural mechanisms by which general anesthetics induce unconsciousness remain undetermined,with ongoing debate over whether they primarily affect the cortex directly or act predominantly on the sleep–wake brain regions.There is an urgent need for high-precision methodologies to detect and analyze neural information across cortical and subcortical regions.In this study,we designed and fabricated the microelectrode arrays to detect electrophysiological signals from nine brain regions,ranging from the secondary motor cortex to the preoptic area in mice under different concentrations of isoflurane anesthesia.The results demonstrate that isoflurane induces a synchronous inhibitory effect on neural activity in both cortical and subcortical regions of mice during the maintenance phase of anesthesia,which intensifies with increasing anesthesia concentration.Moreover,cortical neurons exhibit a more pronounced inhibitory response to isoflurane,as reflected by significant reductions in local field potential power and spike firing rates compared to subcortical neurons during the suppression phase.These findings suggest that isoflurane during the maintenance phase of anesthesia is more likely to align with the“top-down”paradigm by directly inhibiting cortical regions to maintain unconsciousness.In summary,these discoveries could further refine the study of the neural mechanisms of isoflurane-induced unconsciousness.展开更多
Tauopathies describe a group of neurodegenerative diseases in which the protein tau,encoded by the gene MAPT,is aberrantly misfolded,leading to tau aggregation,neural dysfunction,and cell death（Spillantini and Goeder...Tauopathies describe a group of neurodegenerative diseases in which the protein tau,encoded by the gene MAPT,is aberrantly misfolded,leading to tau aggregation,neural dysfunction,and cell death（Spillantini and Goedert,2013）.In Alzheimer＇s disease（AD）,tau forms the characteristic intracellular neurofibrillary tangles（NFTs）,which are thought to be the major cause of neurodegeneration（Bloom,2014）.In other tauopathies,including frontotemporal dementia with Parkinsonism linked to chromo- some 17 （FTDP-17T）, corticobasal degeneration and progressive supranuclear palsy, there are specific forms of tau aggregates and filaments without any amyloid pathology, demonstrating tau＇s po- tent disease-causing potential （Spillantini and Goedert, 2013）. Tau is a microtubule （MT） binding protein, which becomes abnormally hyperphosphorylated on several residues prior/during the process of aggregation, thereby causing loss of its MT binding activity （Mandelkow and Mandelkow, 2012）.展开更多
FoF1-ATPase is an active rotary motor,and generates three-ATP for each rotation.At saturated substrate concentration,the motor can achieve about 103 r.p.m,which means one motor can generate about 105 ATP molecules dur...FoF1-ATPase is an active rotary motor,and generates three-ATP for each rotation.At saturated substrate concentration,the motor can achieve about 103 r.p.m,which means one motor can generate about 105 ATP molecules during 30 min.Here,we constituted a novel nanodevice with a molecular rotary motor and a“battery”,FoF1-ATPase and chromatophore,and presented a novel method of sandwich type rotary biosensor based on εsubunit with one target-to-one motor,in which one target corresponds 105 ATP molecules as detection signals during 30 min.The target such as NT-proBNP detection demonstrated that this novel nanodevice has potential to be developed into an ultrasensitive biosensor to detect low expressed targets.展开更多
BACKGROUND Klebsiella pneumoniae(K.pneumoniae)is an infective microorganism of worldwide concern because of its varied manifestations and life-threatening potential.Genetic analyses have revealed that subspecies of K....BACKGROUND Klebsiella pneumoniae(K.pneumoniae)is an infective microorganism of worldwide concern because of its varied manifestations and life-threatening potential.Genetic analyses have revealed that subspecies of K.pneumoniae exhibit higher virulence and mortality.However,infections with Klebsiella subspecies are often misdiagnosed and underestimated in the clinic because of difficulties in distinguishing K.pneumoniae from its subspecies using routine tests.This case study reports the rapid and fatal effects of K.pneumoniae subspecies.CASE SUMMARY A 52-year-old male patient was febrile and admitted to hospital.Examinations excluded viral and fungal causes along with mycoplasma/chlamydia and parasitic infections.Bacterial cultures revealed blood-borne K.pneumoniae sensitive to carbapenem antibiotics,although corresponding treatment failed to improve the patient’s symptoms.His condition worsened and death occurred within 72 h of symptom onset from sepsis shock.Application of the PMseq-DNA Pro high throughput gene detection assay was implemented with results obtained after death showing a mixed infection of K.pneumoniae and Klebsiella variicola(K.variicola).Clinical evidence suggested that K.variicola rather than K.pneumoniae contributed to the patient’s poor prognosis.CONCLUSION This is the first case report to show patient death from Klebsiella subspecies infection within a short period of time.This case provides a timely reminder of the clinical hazards posed by Klebsiella subspecies and highlights the limitations of classical laboratory methods in guiding anti-infective therapies for complex cases.Moreover,this report serves as reference for physicians diagnosing similar diseases and provides a recommendation to employ early genetic detection to aid patient diagnosis and management.展开更多
Fuzzy logic detection has been applied to the signal enhancement of ultrasonic flaw echoes from the structure noise due to nonflaw related scattering of ultrasound in highly scattering materials. Cross-correlation, ph...Fuzzy logic detection has been applied to the signal enhancement of ultrasonic flaw echoes from the structure noise due to nonflaw related scattering of ultrasound in highly scattering materials. Cross-correlation, phase difference and fractal dimension are used as signal characteristics in fuzzy logic detection. Experimental results show that this new method has better performance than the commonly used correlation detection.展开更多
The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI...The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.展开更多
Single-cell RNA-seq (scRNA-seq) allows the analysis of gene expression in each cell, which enables the detection of highly variable genes (HVG) that contribute to cell-to-cell variation within a homogeneous cell popul...Single-cell RNA-seq (scRNA-seq) allows the analysis of gene expression in each cell, which enables the detection of highly variable genes (HVG) that contribute to cell-to-cell variation within a homogeneous cell population. HVG detection is necessary for clustering analysis to improve the clustering result. scRNA-seq includes some genes that are expressed with a certain probability in all cells which make the cells indistinguishable. These genes are referred to as background noise. To remove the background noise and select the informative genes for clustering analysis, in this paper, we propose an effective HVG detection method based on principal component analysis (PCA). The proposed method utilizes PCA to evaluate the genes (features) on the sample space. The distortion-free principal components are selected to calculate the distance from the origin to gene as the weight of each gene. The genes that have the greatest distances to the origin are selected for clustering analysis. Experimental results on both synthetic and gene expression datasets show that the proposed method not only removes the background noise to select the informative genes for clustering analysis, but also outperforms the existing HVG detection methods.展开更多
A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the det...A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the detectors can be transmitted to diagnosing systems kilometers away with high fidelity. It can adapt to interference and a hostile detecting environment by using the intelligent functions of this system. The feasibility and reliability of this system is verified by system evaluation tests.展开更多
Pringe array is proposed as the cooperated target in the precise torsion angle detection. The target fringe array image is generated according to the structure of the optical system, and the torsion angle detection al...Pringe array is proposed as the cooperated target in the precise torsion angle detection. The target fringe array image is generated according to the structure of the optical system, and the torsion angle detection algorithm is analyzed in response to the gray distribution of the image. The factors affecting the detection precision of the fringe torsion angle are analyzed theoretically and numerically. It indicates that the detection precision of the torsion angle is 1 angular second or even less, carefully selecting the detector array. Significantly, experiments are performed to demonstrate the precision and the results match well with the simulations.展开更多
A hollow-core metal-cladding waveguide（HCMW） optofluidic resonator that works based on a free-space coupling technique is designed. An HCMW can excite ultra-high-order modes（UOMs） at the coupled angle, which can b...A hollow-core metal-cladding waveguide（HCMW） optofluidic resonator that works based on a free-space coupling technique is designed. An HCMW can excite ultra-high-order modes（UOMs） at the coupled angle, which can be used as an optofluidic resonator to detect alterations of the epidermal growth factor receptor（EGFR）concentration. Theoretical analysis shows that the UOMs excited in the HCMW have a highly sensitive response to the refractive index（RI） variation of the guiding layer. An EGFR solution with a 0.2 ng/mL alteration is detected, and the RI variation caused by the concentration alteration is about 2.5 × 10^（-3）.展开更多
Low Earth Orbit(LEO)satellites,with their wide coverage and large number,have gradually become a crucial platform and means for navigation and positioning services.Compared to other LEO constellations,Starlink has ove...Low Earth Orbit(LEO)satellites,with their wide coverage and large number,have gradually become a crucial platform and means for navigation and positioning services.Compared to other LEO constellations,Starlink has over 6000 satellites in orbit,and its signals contain synchronous sequences usable for pseudo-range positioning.Thus,it has a potential serve as an alternative to Global Navigation Satellite System(GNSS)for providing Positioning,Navigation,and Timing(PNT)services.Compared to parabolic antennas and electronically scanned phased array antennas for receiving Starlink signals,wide-beam antennas(such as Low-Noise Block(LNB)downconverters)can be used to achieve low-cost multi-satellite tracking.However,it also encounters the issues of distinguishing between multiple satellite signals and low received signal power,which requires high-sensitivity detection.Moreover,there are some other issues such as unknown signal transmission time and real-time satellite orbits,thereby causing failure to navigation.Accordingly,this study focuses on LEO constellations represented by Starlink,proposes a joint pseudo-range and Doppler positioning method for Starlink satellite Signals of Opportunity(SOP)based on the comprehensive utilization of signals and information from LEO satellites.Moreover,this study analyzes the signal detection capability and satellite isolation method,examines the algorithm’s orbital error suppression performance,and establishes the concept of Equivalent Position Dilution of Precision(EPDOP)S_(EPDOP)for joint pseudo-range and Doppler positioning.In the experiment because Starlink satellite signals are not available in China,we take the advantage of Iridium NEXT satellites’global seamless coverage,utilize an algorithm to get pseudo-range observations with the Iridium NEXT signals,and then combine them with Starlink Doppler observations to achieve the joint pseudo-range and Doppler positioning of LEO satellites’SOPs.The experiment results demonstrate that when relying on Starlink Doppler observations for positioning,the proposed method achieves Two-Dimensional(2D)positioning accuracy of 3.6 m and Three-Dimensional(3D)positioning accuracy of 6.2 m.Compared to existing Starlink positioning algorithms based on parabolic antennas and electronically scanned phased array antennas,this method improves the accuracy by at least 35.7%.Additionally,Iridium NEXT signals are used to validate the performance of the proposed algorithm for joint pseudo-range and Doppler positioning.In a 40 km long-baseline scenario,the algorithm achieved a 2D positioning accuracy of 24 m and a 3D positioning accuracy of 41 m with Iridium NEXT satellite pseudo-range and Doppler measurements.展开更多
基金the Innovation Program for Quantum Science and Technology(Grant No.2023ZD0300100)the National Key Research and Development Program of China(Grant Nos.2023YFB3809600 and 2023YFC3007801)+1 种基金the National Natural Science Foundation of China(Grant Nos.62301543 and U24A20320)the Shanghai Sailing Program(Grant No.21YF1455700).
文摘Conventional superconducting nanowire single-photon detectors(SNSPDs)have been typically limited in their applications due to their size,weight,and power consumption,which confine their use to laboratory settings.However,with the rapid development of remote imaging,sensing technologies,and long-range quantum communication with fewer topographical constraints,the demand for high-efficiency single-photon detectors integrated with avionic platforms is rapidly growing.We herein designed and manufactured the first drone-based SNSPD system with a system detection efficiency(SDE)as high as 91.8%.This drone-based system incorporates high-performance NbTiN SNSPDs,a self-developed miniature liquid helium dewar,and custom-built integrated electrical setups,making it capable of being launched in complex topographical conditions.Such a drone-based SNSPD system may open the use of SNSPDs for applications that demand high SDE in complex environments.
基金This project was supported by the Guangdong Provincial Foundation of Natural Science(021808)
文摘A rapid method to determine glutamic acid (Glu) in cerebrospinal fluid (CSF) by capillaryelectrophoresis with high frequency conductivity detection (contactless conductivity detection) wasdescribed. The CSF sample was pretreated with silver cation resin to remove high concentration ofCl- ions in CSF. The separation was achieved in the buffer solution of 10 mmol/L Tris and 8mmol/L boric acid at the separation voltage of 20.0 kV. Glu showed linear response in the range of5.0×10-6 to 6.0×10-3 mol/L, the limit of detection was 1.0×10-6 mol/L. The method was used foranalysis Glu in CSF satisfactorily with a recovery of 97.8-98.8%.
基金supported by the Natural Science Foundation of Heilongjiang Province(No.B201307)the Ministry of Education of Heilongjiang Province(No.12531192)the Program for Scientific and Technological Innovation Team Construction in Universities of Heilongjiang Province(No.2011TD010)
文摘A novel analytical method was developed for determining morpholinium cations lacking ultraviolet absorption groups.This determination was carried out by high performance liquid chromatographyindirect ultraviolet（HPLC-1UV） detection using imidazolium ionic liquid as background absorption reagents,and imidazolium ionic liquid aq.soln.-organic solvent as mobile phase by a reversed-phase C18 column.The background ultraviolet absorption reagents,imidazolium ionic liquids and organic solvents were investigated.The imidazolium ionic liquid in the mobile phase is not only the background ultraviolet absorption reagent for IUV,but also an active component to improve the separation of morpholinium cations.It was found that morpholinium cations could be adequately determined when0.5 mmol/L 1-ethyl-3-methylimidazolium tetrafluoroborate aq.soln./methanol（80：20,v/v） was used as mobile phase with an IUV detection wavelength of 210 nm.In this study,the baseline separation of Nmethyl,ethylmorpholinium cations（MEMo） and N-methyl.propylmorpholinium cations（MPMo） was successfully achieved in 8.5 min.The detection limits（S/N = 3） for MEMo and MPMo were 0.15 and0.29 mg/L,respectively.This simple and practical method has been successfully applied to the determination of two morpholinium ionic liquids synthesized by the chemistry laboratory.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0400104 and2016YFB0400301the National Natural Sciences Foundation of China under Grant No 61334002the National Science and Technology Major Project
文摘Gallium nitride- （GaN） based high electron mobility transistors （HEMTs） provide a good platform for biological detection. In this work, both Au-gated AlInN/GaN HEMT and AlGaN/GaN HEMT biosensors are fabricated for the detection of deoxyribonucleic acid （DNA） hybridization. The Au-gated AIInN/GaN HEMT biosensor exhibits higher sensitivity in comparison with the AlGaN/GaN HEMT biosensor. For the former, the drain-source current （VDS = 0.5 V） shows a clear decrease of 69μA upon the introduction of 1μmolL^-1 （μM） complimentary DNA to the probe DNA at the sensor area, while for the latter it is only 38 μA. This current reduction is a notable indication of the hybridization. The high sensitivity can be attributed to the thinner barrier of the AlInN/GaN heterostructure, which makes the two-dimensional electron gas channel more susceptible to a slight change of the surface charge.
基金Supported by the National Key Research and Development Program of China under Grant Nos 2016YFB0400104 and 2016YFB0400301the National Natural Science Foundation of China under Grant No 61334002the National Science and Technology Major Project
文摘As one of the most important tumor-associated antigens of colorectal adenocarcinoma, the carcinoembryonic antigen （CEA） threatens human health seriously ali over the globe. Fast electrical and highly sensitive detection of the CEA with A1GaN/GaN high electron mobility transistor is demonstrated experimentally. To achieve a low detection limit, the Au-gated sensing area of the sensor is functionalized with a CEA aptamer instead of the corresponding antibody. The proposed aptasensor has successfully detected different concentrations （ranging from 50picogram/milliliter （pg/ml） to 50 nanogram/milliliter （ng/ml）） of CEA and achieved a detection limit as low as 50pg/ml at Vas = 0.5 V. The drain-source current shows a c/ear increase of 11.5μA under this bias.
基金supported by the National Key R&D Program of China(No.2016YFC1402504).
文摘Radioactive iodine gas detection has significant applications in the nuclear industry,particularly in nuclear accident scenarios and nuclear fuel reprocessing facilities.Herein,chemically stable metal-organic frameworks(MOFs)with good affinity for iodine(including Zn(1,3-BDP),UiO-66,UiO-66-NH2,etc.)were computationally screened and drop-casted upon interdigitated electrodes(IDEs).These MOFs were used to develop advanced iodine sensors to achieve the direct electrical detection of I2 gas via impedance spectroscopy measurements.Upon exposure to I2 gas,a similar electrical response change has occurred for all the IDE sensors,despite in the different impedance ratio.In particular,UiO-66-coated sensors exhibited an impedance ratio>103 times,while the modification of amino groups(-NH2)enhanced the sensitivity,exceeding 104 times for UiO-66-NH2,and was accompanied by a better iodine uptake.Notably,the sensors fabricated from Zn(1,3-BDP),which also contained nitrogen atoms,exhibited excellent comprehensive sensing performance,including high sensitivity(with impedance ratio achieving 1.4×106 times),good recyclability,rapid response speed(with impedance change ratio of 250 times within 3 min),low detection limit(about 29 times under 300 ppm I2 vapor at 25°C),and high anti-interference ability.Our theoretical calculations revealed that the underlying I2 sensing mechanism could be attributed to a decreased band gap and enhanced electrical conductivity due to the new electronic states introduced by the adsorbed I2.This work proposes a novel and feasible method for investigating sensing materials and strategies to fabricate high-performance iodine gas sensors,providing a basis for developing nuclear radioactivity monitoring technology and emergency security safeguard equipment.
基金supported by the Project of tacking of key scientifi c and technical problems in Henan Province(192102310033)。
文摘This study employs an N-carboxyanhydride ring-opening polymerization(NCA ROP)signal amplification strategy to construct a novel sensing system for the simple and rapid detection of tobacco mosaic virus RNA(tRNA).In the developed fluorescent biosensor,carboxylated biomagnetic beads serve as carriers for target capture based on the complementary pairing of the aptamer bases.Subsequently,NCA ROP fluorescent peptides are utilized as highly biocompatible signal carriers to achieve sensitive detection of the target.Under the optimal conditions,the biosensor exhibits a broad linear detection range from 1 pM to 10 nM,with a detection limit as low as 0.085 pM.Furthermore,the fluorescent aptamer biosensor demonstrates robust affinity and reliability in recovery experiments involving healthy R ehmannia glutinosa leaf total RNA.This work establishes a robust platform for tRNA analysis,facilitating real-time and early diagnosis of various plant viruses.
基金support fromthe National Key Research and Development Program of China(2023YFF0721700)the National Natural Science Foundation of China(52372003)+2 种基金the Natural Science Foundation of Heilongjiang Province of China(ZD2023E004)the Science and Technology Plan Project of Ji’an City(20233-117685)Fundamental Research Funds for the Central Universities,and the State Key Laboratory of Particle Detection and Electronics(SKLPDE-KF-202414).
文摘With the significant progress of high-energy physics,nuclear science,and technology,the demand for high-performance scintillators is growing rapidly.Among solid-state scintillators,glass scintillators would play a vital role in the field of high-energy radiation detections because of their merits including low cost,batch production,and arbitrariness in shape.In this review article,the research and development of glass scintillators is introduced with respect to the following key parameters including:density,light yield,scintillation decay time,and radiation hardness.The scintillation mechanisms,preparation methods particularly for Ce^(3+)-activated glasses,standard testing methods,scintillation performance,and applications of glass scintillators are comprehensively reviewed and critically discussed.Finally,the problems existing in the research field are presented and the future development directions of glass scintillators for performance improvement are suggested.
文摘The precise neural mechanisms by which general anesthetics induce unconsciousness remain undetermined,with ongoing debate over whether they primarily affect the cortex directly or act predominantly on the sleep–wake brain regions.There is an urgent need for high-precision methodologies to detect and analyze neural information across cortical and subcortical regions.In this study,we designed and fabricated the microelectrode arrays to detect electrophysiological signals from nine brain regions,ranging from the secondary motor cortex to the preoptic area in mice under different concentrations of isoflurane anesthesia.The results demonstrate that isoflurane induces a synchronous inhibitory effect on neural activity in both cortical and subcortical regions of mice during the maintenance phase of anesthesia,which intensifies with increasing anesthesia concentration.Moreover,cortical neurons exhibit a more pronounced inhibitory response to isoflurane,as reflected by significant reductions in local field potential power and spike firing rates compared to subcortical neurons during the suppression phase.These findings suggest that isoflurane during the maintenance phase of anesthesia is more likely to align with the“top-down”paradigm by directly inhibiting cortical regions to maintain unconsciousness.In summary,these discoveries could further refine the study of the neural mechanisms of isoflurane-induced unconsciousness.
基金funded by grant NC/L000741/1 from the National Council of the 3Rs
文摘Tauopathies describe a group of neurodegenerative diseases in which the protein tau,encoded by the gene MAPT,is aberrantly misfolded,leading to tau aggregation,neural dysfunction,and cell death（Spillantini and Goedert,2013）.In Alzheimer＇s disease（AD）,tau forms the characteristic intracellular neurofibrillary tangles（NFTs）,which are thought to be the major cause of neurodegeneration（Bloom,2014）.In other tauopathies,including frontotemporal dementia with Parkinsonism linked to chromo- some 17 （FTDP-17T）, corticobasal degeneration and progressive supranuclear palsy, there are specific forms of tau aggregates and filaments without any amyloid pathology, demonstrating tau＇s po- tent disease-causing potential （Spillantini and Goedert, 2013）. Tau is a microtubule （MT） binding protein, which becomes abnormally hyperphosphorylated on several residues prior/during the process of aggregation, thereby causing loss of its MT binding activity （Mandelkow and Mandelkow, 2012）.
基金This work is supported by the National Basic Research Program of China(973 Program)under grant No.2013CB932804the National Natural Science Foundation of China under Grant No.11574329 and 11322543+2 种基金the Science and Technology Planning Project of General Administration of Quality Supervision,Inspection and Quarantine(AQSIQ)of PR China under Grant No.2015IK011AQSIQ industrial public service scientific research project of the Ministry of Science and Technology of P.R.China under Grant No.201410049The YS101 type high sensitive detector of chemiluminescence was manufactured by Yishang Innovation Technology Co.,Ltd.
文摘FoF1-ATPase is an active rotary motor,and generates three-ATP for each rotation.At saturated substrate concentration,the motor can achieve about 103 r.p.m,which means one motor can generate about 105 ATP molecules during 30 min.Here,we constituted a novel nanodevice with a molecular rotary motor and a“battery”,FoF1-ATPase and chromatophore,and presented a novel method of sandwich type rotary biosensor based on εsubunit with one target-to-one motor,in which one target corresponds 105 ATP molecules as detection signals during 30 min.The target such as NT-proBNP detection demonstrated that this novel nanodevice has potential to be developed into an ultrasensitive biosensor to detect low expressed targets.
基金Supported by Science and Technology Fund of Guizhou Provincial Health CommissionNo. gzwjkj2019-1-067+1 种基金Doctor Foundation of Guizhou Provincial People’s HospitalNo. GZSYBS[2019]04
文摘BACKGROUND Klebsiella pneumoniae(K.pneumoniae)is an infective microorganism of worldwide concern because of its varied manifestations and life-threatening potential.Genetic analyses have revealed that subspecies of K.pneumoniae exhibit higher virulence and mortality.However,infections with Klebsiella subspecies are often misdiagnosed and underestimated in the clinic because of difficulties in distinguishing K.pneumoniae from its subspecies using routine tests.This case study reports the rapid and fatal effects of K.pneumoniae subspecies.CASE SUMMARY A 52-year-old male patient was febrile and admitted to hospital.Examinations excluded viral and fungal causes along with mycoplasma/chlamydia and parasitic infections.Bacterial cultures revealed blood-borne K.pneumoniae sensitive to carbapenem antibiotics,although corresponding treatment failed to improve the patient’s symptoms.His condition worsened and death occurred within 72 h of symptom onset from sepsis shock.Application of the PMseq-DNA Pro high throughput gene detection assay was implemented with results obtained after death showing a mixed infection of K.pneumoniae and Klebsiella variicola(K.variicola).Clinical evidence suggested that K.variicola rather than K.pneumoniae contributed to the patient’s poor prognosis.CONCLUSION This is the first case report to show patient death from Klebsiella subspecies infection within a short period of time.This case provides a timely reminder of the clinical hazards posed by Klebsiella subspecies and highlights the limitations of classical laboratory methods in guiding anti-infective therapies for complex cases.Moreover,this report serves as reference for physicians diagnosing similar diseases and provides a recommendation to employ early genetic detection to aid patient diagnosis and management.
文摘Fuzzy logic detection has been applied to the signal enhancement of ultrasonic flaw echoes from the structure noise due to nonflaw related scattering of ultrasound in highly scattering materials. Cross-correlation, phase difference and fractal dimension are used as signal characteristics in fuzzy logic detection. Experimental results show that this new method has better performance than the commonly used correlation detection.
基金Supported by the National Natural Science Foundation of China （20906052）, the Science Foundation of Nantong City Municipality （K2007011, K2008023）, the Science Foundation of Nantong University （08R08） and the University Science Research Project of Jiangsu Province （09KJB530008）.
文摘The analysis of sucrose esters with long acyl chain by improved high performance liquid chromatographic method with evaporative light scattering detection （HPLC-ELSD） and electrospray ionization mass spectrum （ESI-MS） is investigated. The improved HPLC-ELSD method for the separation and quantitation of commercial and synthesized sucrose esters is described. Samples are analyzed by means of a reversed-phase （RP） HPLC using a Hypersil C8 column （250 mm× 4.6 mm, 5 μm particle size） with methanol-tetrahydrofuran （vo）ume ratio of 90 ： 10） and water under gradientcondition as the mobile phase, in which the flow rate is 1.0 ml·min^-1 and the column temperature is set at 40℃. This procedure provides a complete separation and determination ot monoester, diester, triester and higher esters with different acyl chain lengths in each fraction by a single run, in combination with the ESI-MS technology. With this method, it is possible to determine the approximate compositions of monoto polyesters in one analysis and quantitate pure positional isomers precisely using an external standard method. It is found that the method of ESI-MS coupling with HPLC system for the analysis of sucrose esters is straight forward, rapid and inexpensive, and can be readily applied in synthesis, purification and structure studies.
基金supported in part by the New Energy and Industrial Technology Development Organization (AJD30064) and JST COI-NEXT.
文摘Single-cell RNA-seq (scRNA-seq) allows the analysis of gene expression in each cell, which enables the detection of highly variable genes (HVG) that contribute to cell-to-cell variation within a homogeneous cell population. HVG detection is necessary for clustering analysis to improve the clustering result. scRNA-seq includes some genes that are expressed with a certain probability in all cells which make the cells indistinguishable. These genes are referred to as background noise. To remove the background noise and select the informative genes for clustering analysis, in this paper, we propose an effective HVG detection method based on principal component analysis (PCA). The proposed method utilizes PCA to evaluate the genes (features) on the sample space. The distortion-free principal components are selected to calculate the distance from the origin to gene as the weight of each gene. The genes that have the greatest distances to the origin are selected for clustering analysis. Experimental results on both synthetic and gene expression datasets show that the proposed method not only removes the background noise to select the informative genes for clustering analysis, but also outperforms the existing HVG detection methods.
基金Supported by National High Technology Research and Development Program of China(2007AA01Z275 )
文摘A digital transmission system with 900 MHz bandwidth and over 40 dB linear dynamic range for high intensity pulsed radial detection is designed. The transient signals （with a subnanoseconds rising edge） from the detectors can be transmitted to diagnosing systems kilometers away with high fidelity. It can adapt to interference and a hostile detecting environment by using the intelligent functions of this system. The feasibility and reliability of this system is verified by system evaluation tests.
基金the National Natural Science Foundation of China under Grant No.61275002.
文摘Pringe array is proposed as the cooperated target in the precise torsion angle detection. The target fringe array image is generated according to the structure of the optical system, and the torsion angle detection algorithm is analyzed in response to the gray distribution of the image. The factors affecting the detection precision of the fringe torsion angle are analyzed theoretically and numerically. It indicates that the detection precision of the torsion angle is 1 angular second or even less, carefully selecting the detector array. Significantly, experiments are performed to demonstrate the precision and the results match well with the simulations.
基金supported by the National Natural Science Foundation of China(No.61235009)the National Basic Research Programmer of China(No.2013CBA01703)
文摘A hollow-core metal-cladding waveguide（HCMW） optofluidic resonator that works based on a free-space coupling technique is designed. An HCMW can excite ultra-high-order modes（UOMs） at the coupled angle, which can be used as an optofluidic resonator to detect alterations of the epidermal growth factor receptor（EGFR）concentration. Theoretical analysis shows that the UOMs excited in the HCMW have a highly sensitive response to the refractive index（RI） variation of the guiding layer. An EGFR solution with a 0.2 ng/mL alteration is detected, and the RI variation caused by the concentration alteration is about 2.5 × 10^（-3）.
基金support is received from the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA0350101)the Project(E2M4140306).
文摘Low Earth Orbit(LEO)satellites,with their wide coverage and large number,have gradually become a crucial platform and means for navigation and positioning services.Compared to other LEO constellations,Starlink has over 6000 satellites in orbit,and its signals contain synchronous sequences usable for pseudo-range positioning.Thus,it has a potential serve as an alternative to Global Navigation Satellite System(GNSS)for providing Positioning,Navigation,and Timing(PNT)services.Compared to parabolic antennas and electronically scanned phased array antennas for receiving Starlink signals,wide-beam antennas(such as Low-Noise Block(LNB)downconverters)can be used to achieve low-cost multi-satellite tracking.However,it also encounters the issues of distinguishing between multiple satellite signals and low received signal power,which requires high-sensitivity detection.Moreover,there are some other issues such as unknown signal transmission time and real-time satellite orbits,thereby causing failure to navigation.Accordingly,this study focuses on LEO constellations represented by Starlink,proposes a joint pseudo-range and Doppler positioning method for Starlink satellite Signals of Opportunity(SOP)based on the comprehensive utilization of signals and information from LEO satellites.Moreover,this study analyzes the signal detection capability and satellite isolation method,examines the algorithm’s orbital error suppression performance,and establishes the concept of Equivalent Position Dilution of Precision(EPDOP)S_(EPDOP)for joint pseudo-range and Doppler positioning.In the experiment because Starlink satellite signals are not available in China,we take the advantage of Iridium NEXT satellites’global seamless coverage,utilize an algorithm to get pseudo-range observations with the Iridium NEXT signals,and then combine them with Starlink Doppler observations to achieve the joint pseudo-range and Doppler positioning of LEO satellites’SOPs.The experiment results demonstrate that when relying on Starlink Doppler observations for positioning,the proposed method achieves Two-Dimensional(2D)positioning accuracy of 3.6 m and Three-Dimensional(3D)positioning accuracy of 6.2 m.Compared to existing Starlink positioning algorithms based on parabolic antennas and electronically scanned phased array antennas,this method improves the accuracy by at least 35.7%.Additionally,Iridium NEXT signals are used to validate the performance of the proposed algorithm for joint pseudo-range and Doppler positioning.In a 40 km long-baseline scenario,the algorithm achieved a 2D positioning accuracy of 24 m and a 3D positioning accuracy of 41 m with Iridium NEXT satellite pseudo-range and Doppler measurements.
