Implanted neural probes can detect weak discharges of neurons in the brain by piercing soft brain tissue,thus as important tools for brain science research,as well as diagnosis and treatment of brain diseases.However,...Implanted neural probes can detect weak discharges of neurons in the brain by piercing soft brain tissue,thus as important tools for brain science research,as well as diagnosis and treatment of brain diseases.However,the rigid neural probes,such as Utah arrays,Michigan probes,and metal microfilament electrodes,are mechanically unmatched with brain tissue and are prone to rejection and glial scarring after implantation,which leads to a significant degradation in the signal quality with the implantation time.In recent years,flexible neural electrodes are rapidly developed with less damage to biological tissues,excellent biocompatibility,and mechanical compliance to alleviate scarring.Among them,the mechanical modeling is important for the optimization of the structure and the implantation process.In this review,the theoretical calculation of the flexible neural probes is firstly summarized with the processes of buckling,insertion,and relative interaction with soft brain tissue for flexible probes from outside to inside.Then,the corresponding mechanical simulation methods are organized considering multiple impact factors to realize minimally invasive implantation.Finally,the technical difficulties and future trends of mechanical modeling are discussed for the next-generation flexible neural probes,which is critical to realize low-invasiveness and long-term coexistence in vivo.展开更多
Rheumatoid arthritis(RA)is a systemic autoimmune disease that is primarily manifested as synovitis and polyarticular opacity and typically leads to serious joint damage and irreversible disability,thus adversely affec...Rheumatoid arthritis(RA)is a systemic autoimmune disease that is primarily manifested as synovitis and polyarticular opacity and typically leads to serious joint damage and irreversible disability,thus adversely affecting locomotion ability and life quality.Consequently,good prognosis heavily relies on the early diagnosis and effective therapeutic monitoring of RA.Activatable fluorescent probes play vital roles in the detection and imaging of biomarkers for disease diagnosis and in vivo imaging.Herein,we review the fluorescent probes developed for the detection and imaging of RA biomarkers,namely reactive oxygen/nitrogen species(hypochlorous acid,peroxynitrite,hydroxyl radical,nitroxyl),pH,and cysteine,and address the related challenges and prospects to inspire the design of novel fluorescent probes and the improvement of their performance in RA studies.展开更多
The MINimal emission FLUXes(MINFLUX)technique in optical microscopy,widely recognized as the next innovative fluorescence microscopy method,claims a spatial resolution of 1-3 nm in both dead and living cells.To make u...The MINimal emission FLUXes(MINFLUX)technique in optical microscopy,widely recognized as the next innovative fluorescence microscopy method,claims a spatial resolution of 1-3 nm in both dead and living cells.To make use of the full resolution of the MINFLUX microscope,it is important to select appropriate fluorescence probes and labeling strategies,especially in living-cell imaging.This paper mainly focuses on recent applications and developments of fluorescence probes and the relevant labeling strategy for MINFLUX microscopy.Moreover,we discuss the deficiencies that need to be addressed in the future and a plan for the possible progression of MINFLUX to help investigators who have been involved in or are just starting in the field of super-resolution imaging microscopy with theoretical support.展开更多
In this article,the effect of the finite conductive surface area of a satellite on the use of satellite-based Langmuir probes is reviewed in light of the basic theory of asymmetric double Langmuir probes(ADLPs).Recent...In this article,the effect of the finite conductive surface area of a satellite on the use of satellite-based Langmuir probes is reviewed in light of the basic theory of asymmetric double Langmuir probes(ADLPs).Recent theoretical and experimental studies have discussed electron sheath/presheath formation and the electron Bohm criterion along with their implications for satellite-based Langmuir probes.The effects predicted by the latest theory of the electron Bohm criterion were not experimentally observed and the experimental results remain supportive of a critical area ratio(A_(L)/A_(S))_(crit)=(m_(i)/(2.3m_(e)))^(1/2)between the probe area A_(S)and the satellite area A_L as conventionally believed.A satellite-based Langmuir probe must satisfy this criterion to physically act as a single Langmuir probe.However,experimental investigations also found that high-energy electrons adversely affect(A_(L)/A_(S))_(crit)and a Langmuir probe's signal quality by giving additional electron current to A_(L).Based on these results,a number of limitations of the maximum probe area are derived when designing satellite-based Langmuir probes,with consideration of both the aim of the satellite and the plasma where the satellite-based probe works.These proposed measures are expected to only partially alleviate the effect of the inadequate satellite surface area on the application of satellite-based Langmuir probes.Using a larger satellite to carry a Langmuir probe remains the most viable means to obtain precise space plasma parameters.展开更多
We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectroly...We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectrolyte (PE) multilayers,for which Au@Ag-NRs were controlled by adjusting the silver layer thickness.The effect of silver layer thickness of Au@Ag-NRs on the SERS performance of the fiber probe was investigated.The SERS fiber probe shows the best performance when the silver layer thickness is controlled at 8.57 nm.Under the condition of optimizing silver layer thickness,the fiber probe exhibits ultra-high sensitivity (i e,10^(-10) M crystalline violet,CV),good reproducibility (i e,RSD of 3.5%) and stability.Besides,electromagnetic field distribution of the SERS fiber probe was also investigated.The strongest enhancement is found within the core of fiber,whereas a weakened electromagnetic field exists in the fiber cladding layer.The SERS fiber probe can be a good candidate in ultra-trace detection for biomedical and environmental areas.展开更多
Haynaldia villosa is a wild relative of wheat and a valuable gene resource for wheat improvement.Owing to the limited number of probes available for fluorescence in situ hybridization(FISH),the resolution at which the...Haynaldia villosa is a wild relative of wheat and a valuable gene resource for wheat improvement.Owing to the limited number of probes available for fluorescence in situ hybridization(FISH),the resolution at which the karyotype of H.villosa can be characterized is poor,hampering accurate characterization of small segmental alien introgressions.We designed ten oligonucleotide probes using tandem repeats in DNA sequences derived from the short arm of H.villosa chromosome 6 V(6 VS).FISH with seven of them resulted in clear signals on H.villosa chromosomes.Using these,we constructed FISH karyotypes for H.villosa using oligo-6 VS-1 and oligo-6 VS-35 oligonucleotides and characterized the distribution of the two probes in five different H.villosa accessions.The new FISH probes can efficiently characterize H.villosa introgressions into wheat.展开更多
Highly sensitive methods are important for monitoring the concentration of metal ions in industrial wastewater.Here,we developed a new probe for the determination of metal ions by fluorescence quenching.The probe cons...Highly sensitive methods are important for monitoring the concentration of metal ions in industrial wastewater.Here,we developed a new probe for the determination of metal ions by fluorescence quenching.The probe consists of hydroxylated graphene quantum dots(H-GQDs),prepared from GQDs by electrochemical method followed by surface hydroxylation.It is a non-reactive indicator with high sensitivity and detection limits of 0.01μM for Cu2+,0.005μM for Al3+,0.04μM for Fe3+,and 0.02μM for Cr3+.In addition,the low biotoxicity and excellent solubility of H-GQDs make them promising for application in wastewater metal ion detection.展开更多
Using wave measurements from the EMFISIS instrument onboard Van Allen Probes,we investigate statistically the spatial distributions of the intensity of plasmaspheric hiss waves.To reproduce these empirical results,we ...Using wave measurements from the EMFISIS instrument onboard Van Allen Probes,we investigate statistically the spatial distributions of the intensity of plasmaspheric hiss waves.To reproduce these empirical results,we establish a fitting model that is a thirdorder polynomial function of L-shell,magnetic local time(MLT),magnetic latitude(MLAT),and AE*.Quantitative comparisons indicate that the model’s fitting functions can reflect favorably the major empirical features of the global distribution of hiss wave intensity,including substorm dependence and the MLT asymmetry.Our results therefore provide a useful analytic model that can be readily employed in future simulations of global radiation belt electron dynamics under the impact of plasmaspheric hiss waves in geospace.展开更多
We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting n...We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting nanoparticles (NPs) were characterized in terms of UV, fluorescence and FT-IR spectroscopy and TEM. The results show that the new NPs display more intense fluorescence intensity and are more stable than its precursors of the type SiO2/CdTe. Under the optimum, the novel NPs exhibit a higher selectivity and ultrasensitive fluorescence probes for the determination of gly-phosate over other pesticides, the fluorescence intensity increase with the concentration of glyphosate in the range from 1.0 to 25.0 nmol/L and the detection limit is low to 0.0725 nmol/L. A mechanism is suggested to explain the inclusion process by a Langmuir binding isotherm.展开更多
Parameters of hydrogen plasma in a miniature Penning discharge ion source, including the electron temperature and the electron density, were measured by using double probes. The results indicate that the electron dens...Parameters of hydrogen plasma in a miniature Penning discharge ion source, including the electron temperature and the electron density, were measured by using double probes. The results indicate that the electron density increases and the electron temperature decreases with the increase in gas pressure and the discharge current. The electron temperature is about 5 - 9 eV and the electron density is 6.0× 10^13 ~ 1.2 × 10^14 m^-3 while the discharge current is in a range of 50 - 120 μA.展开更多
Recent years have seen the design and implementation of many optical activatable smart probes.These probes are activatable because they change their optical properties and are smart because they can identify specific ...Recent years have seen the design and implementation of many optical activatable smart probes.These probes are activatable because they change their optical properties and are smart because they can identify specific targets.This broad class of detection agents has allowed previously unperformed visualizations,facilitating the study of diverse biomolecules including enzymes,nucleic acids,ions and reactive oxygen species.Designed to be robust in an in vivo environment,these probes have been used in tissue culture cells and in live small animals.An emerging class of smart probes has been designed to harness the potency of singlet oxygen generating photosensitizers.Combining the discrimination of activatable agents with the toxicity of photosensitizers represents a new and powerful approach to disease treatment.This review highlights some applications of activatable smart probes with a focus on developments of the past decade.展开更多
Gold(Au) nanoparticle HBV DNA or HCV cDNA gene probes were prepared and were used to detect HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection directly by transmission electro...Gold(Au) nanoparticle HBV DNA or HCV cDNA gene probes were prepared and were used to detect HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection directly by transmission electron microscopy (TEM). PCR identifying HBV and HCV in serum of patients with HBV and HCV coinfection was established. Alkanethiol-modified oligonucleotide was bound with self-made Au nanoparticles to form nanoparticle HBV DNA or HCV cDNA gene probes through covalent binding of Au-S. HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection was added to the detection system composed of nanoparticle HBV DNA and(or) HCV cDNA gene probes, The results showed that HBV DNA and HCV RNA could be specifically amplified by PCR. The zones of DNA amplification appeared in 431 bp and 323 bp respectively. When HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection were added to the detection system, TEM displayed the nanoparticles self-assembled into large network aggregates. It was concluded that the detection of HBV and HCV coinfection by TEM was convenient and efficient with high specificity and sensitivity.展开更多
The plasma shape and other paremeters such as /3P, li is important for the tokamak deveice where the plasma has a non-circular cross-section of sufficient elongation. The measuered signals of magnetic probes and flux ...The plasma shape and other paremeters such as /3P, li is important for the tokamak deveice where the plasma has a non-circular cross-section of sufficient elongation. The measuered signals of magnetic probes and flux loops are used to reconstruct the plasma shape and the current profile in device operation and plasma shape feed back control system. So the number and positions of magnetic probes and flux loops provides the basis of the plasma reconstruction. This paper instroduce how to use EFIT code (equilibrium fitting code) to determine the number and positions of the magnetic probes and flux loops. The simulation result is given also.展开更多
OBJECTIVE To describe a highly sensitive LC-ESI MSnmethod that was developed to simultaneously detect six CYP isoform-specific probes and their metabolites in rat plasma for microdosing cocktail study.METHODS After ad...OBJECTIVE To describe a highly sensitive LC-ESI MSnmethod that was developed to simultaneously detect six CYP isoform-specific probes and their metabolites in rat plasma for microdosing cocktail study.METHODS After administration of a mixture of six probes(i.e.,a cocktail approach with caffeine 100μg·kg-1,tolbutamide100μg·kg-1,omeprazole 500μg·kg-1,dextromethorphan 500μg·kg-1,chlorzoxazone 50μg·kg-1and midazolam 100μg·kg-1)to SD rats.The plasma samples were extracted using ethyl acetate with diazepam and gliclazide as the IS.The assay was performed on an Agilent Eclipse Plus C18 column(2.1×50 mm,3.5μm).The mobile phase consisted of 0.01%formic acid(1 mmol·L-1ammonium formate)and acetonitrile.The flow rate was0.3 m L·min-1.The samples were analyzed by LC-20A&5500Qtrap ESI MSnin MRM mode.The MS/MS reaction selected 181.2/124.0 m/z ions for caffeine,195.2/138.2m/z for paraxanthine,269.1/170.0 m/z for tolbutamide,285.1/186.0 m/z for 4-hydroxytolbutamide,346.1/198.1m/z for omeprazole,362.2/214.2 m/z for 5-hydroxyomeprazole,272.3/147.1 m/z for dextromethorphan,258.2/157.0 m/z for dextrorphan,168.1/132.1 m/z for chlorzoxazone,326.1/291.2 m/z for midazolam,and 342.1/324.2m/z for 1′-hydroxymidazolam.RESULTS The datashowed that the method was with good linearity in the range of 0.2-200 ng·m L-1for caffeine,0.1-25 ng·m L-1for paraxanthine,0.05-100 ng·m L-1for omeprazole,0.01-25 ng·mL-1for 5-hydroxyomeprazole,0.1-200 ng·mL-1for dextromethorphan,0.05-12.5 ng·mL-1for dextrophan,0.2-200 ng·mL-1for midazolam,and 0.2-25 ng·mL-1for 1′-hydroxymidazolam,respectively.The stability%RSD for al probes was less than 15%and matrix effects in plasma on the ionization were negligible.CONCLUSION This highly sensitive and quantitative method allowed a pharmacokinetic study in subjects receiving doses 10-100 times lower than typical therapeutic doses.The established LCMS/MS method was suitable for pharmacokinetic study of this mixture cocktail probe group and could be applied deeply to CYP isoforms(1A2,2C9,2C19,2D6,2E1and 3A)research.展开更多
Direct measurement of dipole potential in biological membranes has been impossible and 3-hydroxyflavones(3HFs) have allowed detection of changes in dipole potential in biological systems.In the present study,sixteen d...Direct measurement of dipole potential in biological membranes has been impossible and 3-hydroxyflavones(3HFs) have allowed detection of changes in dipole potential in biological systems.In the present study,sixteen derivatives of 3HF with aliphatic hydrocarbon chains of different lengths at 4′-position and 6-position were synthesized.The basic fluorescence properties of 3HFs are maintained in all the probes in terms of strong blue shift in maximum fluorescence emission wavelength and>100 fold increase in quantum yield in organic solvents and in dioleoylphosphatidylcholine(DOPC) small unilamellar vesicles(SUV) in comparison to in aqueous Hepes buffer(15 mmol/L,pH 7.4).More importantly,the ability of the new compounds to report dipole potential changes in biological systems are also maintained,since all the new probes showed spectrum properties that are similar to yet different from that of F4N1,which potentially may allow more sensitive measurement of the dipole potential change in membranes.展开更多
Tumor vaccination using tumor-associated antigenprimed dendritic cells(DCs)is in clinical trials.Investigators are using patients’own immune systems to activate T-cells against recurrent or metastatic tumors.Followin...Tumor vaccination using tumor-associated antigenprimed dendritic cells(DCs)is in clinical trials.Investigators are using patients’own immune systems to activate T-cells against recurrent or metastatic tumors.Following vaccination of DCs or attenuated tumor cells,clinical as well as radiological improvements have been noted due to migration and accumulation of cytotoxic T-cells(CTLs).CTLs mediated tumor cell killing resulted in extended survival in clinical trails and in preclinical models.Besides administration of primed DCs or attenuated or killed tumors cells to initiate the generation of CTLs,investigators have started making genetically altered T-cells(CTLs)to target specific tumors and showed in vivo migration and accumulation in the implanted or recurrent tumors using different imaging modalities.Our groups have also showed the utilization of both in vivo and in vitro techniques to make CTLs against glioma and used them as imaging probes to determine the sites of tumors.In this short review,the current status of vaccination therapy against glioma and utilization of CTLs as in vivo imaging probes to determine the sites of tumors and differentiate recurrent glioma from radiation necrosis will be discussed.展开更多
Fluorescent molecules - p-dimethylaminobenzonitrile (DMABN) and trans-stilbene (TSB ) - were used as probes to investigate the inner structure of the nanotubular cavities contained in a new polyorganosiloxane (POS) wh...Fluorescent molecules - p-dimethylaminobenzonitrile (DMABN) and trans-stilbene (TSB ) - were used as probes to investigate the inner structure of the nanotubular cavities contained in a new polyorganosiloxane (POS) which was prepared by the hydrosilylation coupling reaction of cis-isotactic ladderlike polyvinylsilsesquioxane (Vi-T) with 1,1,3,3-tetramethyldisiloxane (H-MM) as coupling agent in the presence of catalyst dicyclopentadienyldichloroplatinum (Cp2PtCl2). The results from FTIR spectra and fluorescence spectra in combination with molecular simulation reveal that the cross-section of the nanotubular cavity is nearly rectangular in shape, and is about 0.62 nm in width and about 0.38 nm in height. This work gains in-depth knowledge into the inner structure of the nanotubular cavities of POS and furthermore provides a guide to the selection of proper guest molecules in constructing functional supramolecular clathrate based upon POS.展开更多
During the past several decades,positron emission tomography(PET) has been one of the rapidly growing areas of medical imaging;particularly,its applications in routine oncological practice have been widely recognize...During the past several decades,positron emission tomography(PET) has been one of the rapidly growing areas of medical imaging;particularly,its applications in routine oncological practice have been widely recognized.At present,^18F-fluorodeoxyglucose(^18F-FDG) is the most broadly used PET probe.However,^18F-FDG also suffers many limitations.Thus,scientists and clinicians are greatly interested in exploring and developing new PET imaging probes with high affinity and specificity.In this review,we briefly summarize the representative PET probes beyond ^18F-FDG that are available for patients imaging in three major clinical areas(oncology,neurology and cardiology),and we also discuss the feasibility and trends in developing new PET probes for personalized medicine.展开更多
We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH_3NH_3PbI_3 perovskite, the hole transfer from CH_3NH_3PbI_3 into the organic hole-transporting material(HTM...We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH_3NH_3PbI_3 perovskite, the hole transfer from CH_3NH_3PbI_3 into the organic hole-transporting material(HTM)Spiro-OMe TAD occurs on a sub-picosecond timescale. Second-order recombination is the dominant decay pathway at higher photo-excitation fluences as observed in neat CH_3NH_3PbI_3 films. In contrast, under similar experimental conditions, second-order recombination weakly contributes the relatively slow recombination between the electrons in the perovskite and the injected holes in HTM, as a loss mechanism at the CH_3NH_3PbI_3/Spiro-OMe TAD interface. Our results offer insights into the intrinsic photophysics of CH_3NH_3PbI_3-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.展开更多
基金support received from the National Natural Science Foundation of China(GrantNos.62204204 and 52175148)Science and Technology Innovation 2030-Major Project(Grant No.2022ZD0208601)+1 种基金Shanghai Sailing Program(Grant No.21YF1451000)Presidential Foundation of CAEP(Grant No.YZJJZQ2022001).
文摘Implanted neural probes can detect weak discharges of neurons in the brain by piercing soft brain tissue,thus as important tools for brain science research,as well as diagnosis and treatment of brain diseases.However,the rigid neural probes,such as Utah arrays,Michigan probes,and metal microfilament electrodes,are mechanically unmatched with brain tissue and are prone to rejection and glial scarring after implantation,which leads to a significant degradation in the signal quality with the implantation time.In recent years,flexible neural electrodes are rapidly developed with less damage to biological tissues,excellent biocompatibility,and mechanical compliance to alleviate scarring.Among them,the mechanical modeling is important for the optimization of the structure and the implantation process.In this review,the theoretical calculation of the flexible neural probes is firstly summarized with the processes of buckling,insertion,and relative interaction with soft brain tissue for flexible probes from outside to inside.Then,the corresponding mechanical simulation methods are organized considering multiple impact factors to realize minimally invasive implantation.Finally,the technical difficulties and future trends of mechanical modeling are discussed for the next-generation flexible neural probes,which is critical to realize low-invasiveness and long-term coexistence in vivo.
基金supported by the National Natural Science Foundation of China(82072432)the China-Japan Friendship Hospital Horizontal Project/Spontaneous Research Funding(2022-HX-JC-7)+1 种基金the National High Level Hospital Clinical Research Funding(2022-NHLHCRF-PY-20)the Elite Medical Professionals project of China-Japan Friendship Hospital(ZRJY2021-GG12).
文摘Rheumatoid arthritis(RA)is a systemic autoimmune disease that is primarily manifested as synovitis and polyarticular opacity and typically leads to serious joint damage and irreversible disability,thus adversely affecting locomotion ability and life quality.Consequently,good prognosis heavily relies on the early diagnosis and effective therapeutic monitoring of RA.Activatable fluorescent probes play vital roles in the detection and imaging of biomarkers for disease diagnosis and in vivo imaging.Herein,we review the fluorescent probes developed for the detection and imaging of RA biomarkers,namely reactive oxygen/nitrogen species(hypochlorous acid,peroxynitrite,hydroxyl radical,nitroxyl),pH,and cysteine,and address the related challenges and prospects to inspire the design of novel fluorescent probes and the improvement of their performance in RA studies.
基金supported by the Science and Technology Commission of Shanghai Municipality (21DZ1100500)the Shanghai Municipal Science and Technology Major Project+1 种基金the Shanghai Frontiers Science Center Program (2021-2025 No.20)Shanghai Hong Kong,Macao,and Taiwan Cooperation Project (No.19490760900).
文摘The MINimal emission FLUXes(MINFLUX)technique in optical microscopy,widely recognized as the next innovative fluorescence microscopy method,claims a spatial resolution of 1-3 nm in both dead and living cells.To make use of the full resolution of the MINFLUX microscope,it is important to select appropriate fluorescence probes and labeling strategies,especially in living-cell imaging.This paper mainly focuses on recent applications and developments of fluorescence probes and the relevant labeling strategy for MINFLUX microscopy.Moreover,we discuss the deficiencies that need to be addressed in the future and a plan for the possible progression of MINFLUX to help investigators who have been involved in or are just starting in the field of super-resolution imaging microscopy with theoretical support.
基金supported by National Natural Science Foundation of China(Nos.12275305 and 12205334)the Chinese Academy of Science Hundred Youth Talent Program+1 种基金China Postdoctoral Science Foundation(No.2022M713188)the Director’s Fund of Hefei Institutes of Physical Science,Chinese Academy of Sciences(No.YZJJ2022QN19)。
文摘In this article,the effect of the finite conductive surface area of a satellite on the use of satellite-based Langmuir probes is reviewed in light of the basic theory of asymmetric double Langmuir probes(ADLPs).Recent theoretical and experimental studies have discussed electron sheath/presheath formation and the electron Bohm criterion along with their implications for satellite-based Langmuir probes.The effects predicted by the latest theory of the electron Bohm criterion were not experimentally observed and the experimental results remain supportive of a critical area ratio(A_(L)/A_(S))_(crit)=(m_(i)/(2.3m_(e)))^(1/2)between the probe area A_(S)and the satellite area A_L as conventionally believed.A satellite-based Langmuir probe must satisfy this criterion to physically act as a single Langmuir probe.However,experimental investigations also found that high-energy electrons adversely affect(A_(L)/A_(S))_(crit)and a Langmuir probe's signal quality by giving additional electron current to A_(L).Based on these results,a number of limitations of the maximum probe area are derived when designing satellite-based Langmuir probes,with consideration of both the aim of the satellite and the plasma where the satellite-based probe works.These proposed measures are expected to only partially alleviate the effect of the inadequate satellite surface area on the application of satellite-based Langmuir probes.Using a larger satellite to carry a Langmuir probe remains the most viable means to obtain precise space plasma parameters.
基金Funded by National Natural Science Foundation of China (Nos.51372179, 51772224)the Open Projects Foundation of Yangtze Optical Fiber and Cable Joint Stock Limited Company (YOFC)(No.SKLD1705)。
文摘We demonstrated a chemical process in the fabrication of a SERS fiber probe with an ultrahigh sensitivity.The synthesis was carried out by preparing Au@Ag core-shell nanorods (Au@Ag-NRs) selfassembled on polyelectrolyte (PE) multilayers,for which Au@Ag-NRs were controlled by adjusting the silver layer thickness.The effect of silver layer thickness of Au@Ag-NRs on the SERS performance of the fiber probe was investigated.The SERS fiber probe shows the best performance when the silver layer thickness is controlled at 8.57 nm.Under the condition of optimizing silver layer thickness,the fiber probe exhibits ultra-high sensitivity (i e,10^(-10) M crystalline violet,CV),good reproducibility (i e,RSD of 3.5%) and stability.Besides,electromagnetic field distribution of the SERS fiber probe was also investigated.The strongest enhancement is found within the core of fiber,whereas a weakened electromagnetic field exists in the fiber cladding layer.The SERS fiber probe can be a good candidate in ultra-trace detection for biomedical and environmental areas.
基金supported by the National Key Research and Development Program of China(2016YFD0102001)the National Natural Science Foundation of China(31571653,31771782,31201204,31501305)+3 种基金International Cooperation and Exchange Programme of the National Natural Science Foundation of China(31661143005)Introducing the Technique to Exploring the Genetic Germplasm Based on the Chromosome Sorting and Sequencing(2015-Z41)the Special Fund of Jiangsu Province for the Transformation of Scientific and Technological Achievements(BA2017138)supported by European Regional Development Fund Project“Plants as a Tool for Sustainable Global Development”(CZ.02.1.01/0.0/0.0/16_019/0000827)。
文摘Haynaldia villosa is a wild relative of wheat and a valuable gene resource for wheat improvement.Owing to the limited number of probes available for fluorescence in situ hybridization(FISH),the resolution at which the karyotype of H.villosa can be characterized is poor,hampering accurate characterization of small segmental alien introgressions.We designed ten oligonucleotide probes using tandem repeats in DNA sequences derived from the short arm of H.villosa chromosome 6 V(6 VS).FISH with seven of them resulted in clear signals on H.villosa chromosomes.Using these,we constructed FISH karyotypes for H.villosa using oligo-6 VS-1 and oligo-6 VS-35 oligonucleotides and characterized the distribution of the two probes in five different H.villosa accessions.The new FISH probes can efficiently characterize H.villosa introgressions into wheat.
基金financially supported by the National Natural Science Foundation of China (No. 21674011)Beijing Municipal Natural Science Foundation (No. 2172040)
文摘Highly sensitive methods are important for monitoring the concentration of metal ions in industrial wastewater.Here,we developed a new probe for the determination of metal ions by fluorescence quenching.The probe consists of hydroxylated graphene quantum dots(H-GQDs),prepared from GQDs by electrochemical method followed by surface hydroxylation.It is a non-reactive indicator with high sensitivity and detection limits of 0.01μM for Cu2+,0.005μM for Al3+,0.04μM for Fe3+,and 0.02μM for Cr3+.In addition,the low biotoxicity and excellent solubility of H-GQDs make them promising for application in wastewater metal ion detection.
基金supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB41000000)the NSFC grants 41674163, 41974186, 41704162, 41904144, and 41904143+1 种基金the pre-research projects on Civil Aerospace Technologies No. D020308, D020104 and D020303funded by China National Space Administration。
文摘Using wave measurements from the EMFISIS instrument onboard Van Allen Probes,we investigate statistically the spatial distributions of the intensity of plasmaspheric hiss waves.To reproduce these empirical results,we establish a fitting model that is a thirdorder polynomial function of L-shell,magnetic local time(MLT),magnetic latitude(MLAT),and AE*.Quantitative comparisons indicate that the model’s fitting functions can reflect favorably the major empirical features of the global distribution of hiss wave intensity,including substorm dependence and the MLT asymmetry.Our results therefore provide a useful analytic model that can be readily employed in future simulations of global radiation belt electron dynamics under the impact of plasmaspheric hiss waves in geospace.
文摘We have developed a simple method for the preparation of highly fluorescent and stable, water-soluble CdTe quantum dots in sol-gel-derived composite silica spheres which were coated with calix[6]arene. The resulting nanoparticles (NPs) were characterized in terms of UV, fluorescence and FT-IR spectroscopy and TEM. The results show that the new NPs display more intense fluorescence intensity and are more stable than its precursors of the type SiO2/CdTe. Under the optimum, the novel NPs exhibit a higher selectivity and ultrasensitive fluorescence probes for the determination of gly-phosate over other pesticides, the fluorescence intensity increase with the concentration of glyphosate in the range from 1.0 to 25.0 nmol/L and the detection limit is low to 0.0725 nmol/L. A mechanism is suggested to explain the inclusion process by a Langmuir binding isotherm.
文摘Parameters of hydrogen plasma in a miniature Penning discharge ion source, including the electron temperature and the electron density, were measured by using double probes. The results indicate that the electron density increases and the electron temperature decreases with the increase in gas pressure and the discharge current. The electron temperature is about 5 - 9 eV and the electron density is 6.0× 10^13 ~ 1.2 × 10^14 m^-3 while the discharge current is in a range of 50 - 120 μA.
基金supported by Canadian Cancer Society Grant#018510 through the National Cancer Institute of Canada.
文摘Recent years have seen the design and implementation of many optical activatable smart probes.These probes are activatable because they change their optical properties and are smart because they can identify specific targets.This broad class of detection agents has allowed previously unperformed visualizations,facilitating the study of diverse biomolecules including enzymes,nucleic acids,ions and reactive oxygen species.Designed to be robust in an in vivo environment,these probes have been used in tissue culture cells and in live small animals.An emerging class of smart probes has been designed to harness the potency of singlet oxygen generating photosensitizers.Combining the discrimination of activatable agents with the toxicity of photosensitizers represents a new and powerful approach to disease treatment.This review highlights some applications of activatable smart probes with a focus on developments of the past decade.
基金This project was supported by National Key Basic Research Program of China (No 2007CB512900,2005CB 522901) National Science Foundation of China (No NSFC30571643)
文摘Gold(Au) nanoparticle HBV DNA or HCV cDNA gene probes were prepared and were used to detect HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection directly by transmission electron microscopy (TEM). PCR identifying HBV and HCV in serum of patients with HBV and HCV coinfection was established. Alkanethiol-modified oligonucleotide was bound with self-made Au nanoparticles to form nanoparticle HBV DNA or HCV cDNA gene probes through covalent binding of Au-S. HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection was added to the detection system composed of nanoparticle HBV DNA and(or) HCV cDNA gene probes, The results showed that HBV DNA and HCV RNA could be specifically amplified by PCR. The zones of DNA amplification appeared in 431 bp and 323 bp respectively. When HBV DNA and HCV RNA extracted from positive serum of patients with HBV and HCV coinfection were added to the detection system, TEM displayed the nanoparticles self-assembled into large network aggregates. It was concluded that the detection of HBV and HCV coinfection by TEM was convenient and efficient with high specificity and sensitivity.
基金The project supported by the National Meg-Science Engineering Project of the Chinese Government
文摘The plasma shape and other paremeters such as /3P, li is important for the tokamak deveice where the plasma has a non-circular cross-section of sufficient elongation. The measuered signals of magnetic probes and flux loops are used to reconstruct the plasma shape and the current profile in device operation and plasma shape feed back control system. So the number and positions of magnetic probes and flux loops provides the basis of the plasma reconstruction. This paper instroduce how to use EFIT code (equilibrium fitting code) to determine the number and positions of the magnetic probes and flux loops. The simulation result is given also.
基金The project supported by National Natural Science Foundation of China(81473579,81273654,81102879)the National Science and Technology Major Projects for"Major New Drugs Innovation and Development"(2013ZX09103002-022)
文摘OBJECTIVE To describe a highly sensitive LC-ESI MSnmethod that was developed to simultaneously detect six CYP isoform-specific probes and their metabolites in rat plasma for microdosing cocktail study.METHODS After administration of a mixture of six probes(i.e.,a cocktail approach with caffeine 100μg·kg-1,tolbutamide100μg·kg-1,omeprazole 500μg·kg-1,dextromethorphan 500μg·kg-1,chlorzoxazone 50μg·kg-1and midazolam 100μg·kg-1)to SD rats.The plasma samples were extracted using ethyl acetate with diazepam and gliclazide as the IS.The assay was performed on an Agilent Eclipse Plus C18 column(2.1×50 mm,3.5μm).The mobile phase consisted of 0.01%formic acid(1 mmol·L-1ammonium formate)and acetonitrile.The flow rate was0.3 m L·min-1.The samples were analyzed by LC-20A&5500Qtrap ESI MSnin MRM mode.The MS/MS reaction selected 181.2/124.0 m/z ions for caffeine,195.2/138.2m/z for paraxanthine,269.1/170.0 m/z for tolbutamide,285.1/186.0 m/z for 4-hydroxytolbutamide,346.1/198.1m/z for omeprazole,362.2/214.2 m/z for 5-hydroxyomeprazole,272.3/147.1 m/z for dextromethorphan,258.2/157.0 m/z for dextrorphan,168.1/132.1 m/z for chlorzoxazone,326.1/291.2 m/z for midazolam,and 342.1/324.2m/z for 1′-hydroxymidazolam.RESULTS The datashowed that the method was with good linearity in the range of 0.2-200 ng·m L-1for caffeine,0.1-25 ng·m L-1for paraxanthine,0.05-100 ng·m L-1for omeprazole,0.01-25 ng·mL-1for 5-hydroxyomeprazole,0.1-200 ng·mL-1for dextromethorphan,0.05-12.5 ng·mL-1for dextrophan,0.2-200 ng·mL-1for midazolam,and 0.2-25 ng·mL-1for 1′-hydroxymidazolam,respectively.The stability%RSD for al probes was less than 15%and matrix effects in plasma on the ionization were negligible.CONCLUSION This highly sensitive and quantitative method allowed a pharmacokinetic study in subjects receiving doses 10-100 times lower than typical therapeutic doses.The established LCMS/MS method was suitable for pharmacokinetic study of this mixture cocktail probe group and could be applied deeply to CYP isoforms(1A2,2C9,2C19,2D6,2E1and 3A)research.
文摘Direct measurement of dipole potential in biological membranes has been impossible and 3-hydroxyflavones(3HFs) have allowed detection of changes in dipole potential in biological systems.In the present study,sixteen derivatives of 3HF with aliphatic hydrocarbon chains of different lengths at 4′-position and 6-position were synthesized.The basic fluorescence properties of 3HFs are maintained in all the probes in terms of strong blue shift in maximum fluorescence emission wavelength and>100 fold increase in quantum yield in organic solvents and in dioleoylphosphatidylcholine(DOPC) small unilamellar vesicles(SUV) in comparison to in aqueous Hepes buffer(15 mmol/L,pH 7.4).More importantly,the ability of the new compounds to report dipole potential changes in biological systems are also maintained,since all the new probes showed spectrum properties that are similar to yet different from that of F4N1,which potentially may allow more sensitive measurement of the dipole potential change in membranes.
文摘Tumor vaccination using tumor-associated antigenprimed dendritic cells(DCs)is in clinical trials.Investigators are using patients’own immune systems to activate T-cells against recurrent or metastatic tumors.Following vaccination of DCs or attenuated tumor cells,clinical as well as radiological improvements have been noted due to migration and accumulation of cytotoxic T-cells(CTLs).CTLs mediated tumor cell killing resulted in extended survival in clinical trails and in preclinical models.Besides administration of primed DCs or attenuated or killed tumors cells to initiate the generation of CTLs,investigators have started making genetically altered T-cells(CTLs)to target specific tumors and showed in vivo migration and accumulation in the implanted or recurrent tumors using different imaging modalities.Our groups have also showed the utilization of both in vivo and in vitro techniques to make CTLs against glioma and used them as imaging probes to determine the sites of tumors.In this short review,the current status of vaccination therapy against glioma and utilization of CTLs as in vivo imaging probes to determine the sites of tumors and differentiate recurrent glioma from radiation necrosis will be discussed.
基金This project was co-funded by National Natural Science Foundation of China,Research Foundation of Molecular Science Centre and Director of Institute of Chemistry,Chinese Academy of Sciences and Foundation of Organic Solid Laboratory,Chinese Academy of Sc
文摘Fluorescent molecules - p-dimethylaminobenzonitrile (DMABN) and trans-stilbene (TSB ) - were used as probes to investigate the inner structure of the nanotubular cavities contained in a new polyorganosiloxane (POS) which was prepared by the hydrosilylation coupling reaction of cis-isotactic ladderlike polyvinylsilsesquioxane (Vi-T) with 1,1,3,3-tetramethyldisiloxane (H-MM) as coupling agent in the presence of catalyst dicyclopentadienyldichloroplatinum (Cp2PtCl2). The results from FTIR spectra and fluorescence spectra in combination with molecular simulation reveal that the cross-section of the nanotubular cavity is nearly rectangular in shape, and is about 0.62 nm in width and about 0.38 nm in height. This work gains in-depth knowledge into the inner structure of the nanotubular cavities of POS and furthermore provides a guide to the selection of proper guest molecules in constructing functional supramolecular clathrate based upon POS.
文摘During the past several decades,positron emission tomography(PET) has been one of the rapidly growing areas of medical imaging;particularly,its applications in routine oncological practice have been widely recognized.At present,^18F-fluorodeoxyglucose(^18F-FDG) is the most broadly used PET probe.However,^18F-FDG also suffers many limitations.Thus,scientists and clinicians are greatly interested in exploring and developing new PET imaging probes with high affinity and specificity.In this review,we briefly summarize the representative PET probes beyond ^18F-FDG that are available for patients imaging in three major clinical areas(oncology,neurology and cardiology),and we also discuss the feasibility and trends in developing new PET probes for personalized medicine.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11674213,11604202 and 61735010the Young Eastern Scholar at Shanghai Institutions of Higher Learning under Grant No QD2015020+1 种基金the Universities Young Teachers Training Funding Program under Grant No ZZSD15098the‘Chen Guang’Project of Shanghai Municipal Education Commission and Shanghai Education Development Foundation under Grant No 16CG45
文摘We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH_3NH_3PbI_3 perovskite, the hole transfer from CH_3NH_3PbI_3 into the organic hole-transporting material(HTM)Spiro-OMe TAD occurs on a sub-picosecond timescale. Second-order recombination is the dominant decay pathway at higher photo-excitation fluences as observed in neat CH_3NH_3PbI_3 films. In contrast, under similar experimental conditions, second-order recombination weakly contributes the relatively slow recombination between the electrons in the perovskite and the injected holes in HTM, as a loss mechanism at the CH_3NH_3PbI_3/Spiro-OMe TAD interface. Our results offer insights into the intrinsic photophysics of CH_3NH_3PbI_3-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.