Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate ...Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate and introduced a multiplex-feature analysis strategy based on the coffee ring effect.This substrate not only offers high Raman enhancement but also exhibits a high probability of detection(POD),enabling rapid and accurate identification of 50 nm polystyrene nanoplastics over a broad concentration range(1–10−10 wt%).Importantly,experimental results reveal a strong correlation between the coffee ring formation and the concentration of nanoplastic dispersion.By incorporating Raman signal intensity,coffee ring diameter,and POD as combined features,we established a machine learning-based mapping between nanoplastic concentration and coffee ring characteristics,allowing precise predictions of dispersion concentration.The mean squared error of these predictions is remarkably low,ranging from 0.21 to 0.54,representing a 19 fold improvement in accuracy compared to traditional linear regression-based methods.This strategy effectively integrates SERS with wettability modification techniques,ensuring high sensitivity and fingerprinting capabilities,while addressing the limitations of Raman signal intensity in accurately reflecting concentration changes at ultra-low levels,providing a new idea for precise SERS measurements of nanoplastics.展开更多
Infrared(IR)spectroscopy,a technique within the realm of molecular vibrational spectroscopy,furnishes distinctive chemical signatures pivotal for both structural analysis and compound identification.A notable challeng...Infrared(IR)spectroscopy,a technique within the realm of molecular vibrational spectroscopy,furnishes distinctive chemical signatures pivotal for both structural analysis and compound identification.A notable challenge emerges from the misalignment between the mid-IR light wavelength range and molecular dimensions,culminating in a constrained absorption cross-section and diminished vibrational absorption coefficients(Supplementary data).展开更多
[Objectives]This study was conducted to establish a rapid quantitative method for detecting antibody against Peste des Petits Ruminants Virus(PPR V)in sheep serum.[Methods]Soluble N protein and NH fusion protein were ...[Objectives]This study was conducted to establish a rapid quantitative method for detecting antibody against Peste des Petits Ruminants Virus(PPR V)in sheep serum.[Methods]Soluble N protein and NH fusion protein were obtained in Escherichia coli prokaryotic expression system by optimizing codons and expression conditions of E.coli.Furthermore,based on the purified soluble N protein and NH fusion protein,a high-sensitivity fluorescence immunoassay kit for detecting the antibody against PPR V was established.[Results]The method could quickly and quantitatively detect PPR V antibody in sheep serum,with high sensitivity and specificity,without any cross reaction to other related sheep pathogens.The intra-batch and inter-batch coefficients of variation were less than 10%and 15%,respectively,and the method had good repeatability.Through detection on 292 clinical serum samples,it was compared with the French IDVET competitive ELISA kit,and the coincidence rate of the two methods reached 93.84%.Compared with the serum neutralization test,the detected titer value of the high-sensitivity rapid fluorescence quantitative detection method was basically consistent with the tilter value obtained by the neutralization test on the standard positive serum(provided by the WOAH Brucellosis Reference Laboratory of France).[Conclusions]This method can realize rapid quantitative detection of PPR V antibody on site,and has high practical value and popularization value.展开更多
Objective Shellfish are recognized as important vehicles of norovirus-associated gastroenteritis. The present study aimed to monitor norovirus contamination in oysters along the farm-to-fork continuum in Guangxi, a ma...Objective Shellfish are recognized as important vehicles of norovirus-associated gastroenteritis. The present study aimed to monitor norovirus contamination in oysters along the farm-to-fork continuum in Guangxi, a major oyster production area in Southwestern China. Methods Oyster samples were collected monthly from farms, markets, and restaurants, from January to December 2016. Norovirus was detected and quantified by one-step reverse transcription-droplet digital polymerase chain reaction（RT-ddPCR）. Results A total of 480 oyster samples were collected and tested for norovirus genogroups I and II. Norovirus was detected in 20.7% of samples, with genogroup II predominating. No significant difference was observed in norovirus prevalence among different sampling sites. The norovirus levels varied widely, with a geometric mean of 19,300 copies/g in digestive glands. Both norovirus prevalence and viral loads showed obvious seasonality, with a strong winter bias. Conclusion This study provides a systematic analysis of norovirus contamination ‘from the farm to the fork＇ in Guangxi. RT-ddPCR can be a useful tool for detection and quantification of low amounts of norovirus in the presence of inhibitors found particularly in foodstuffs. This approach will contribute to the development of strategies for controlling and reducing the risk of human illness resulting from shellfish consumption.展开更多
AIM:To establish the more feasible and sensitive assessment approach to the detection of adefovir (ADV) resistance-associated hepatitis B virus (HBV) quasispecies.METHODS: Based on the characteristics of rtA181V/T and...AIM:To establish the more feasible and sensitive assessment approach to the detection of adefovir (ADV) resistance-associated hepatitis B virus (HBV) quasispecies.METHODS: Based on the characteristics of rtA181V/T and rtN236T mutations, a new approach based on real-time fluorescent quantitative polymerase chain reaction (RT-PCR) was established for the detection of ADV-resistant HBV quasispecies, total HBV DNA, rtA181 and rtN236 mutations in blood samples from 32 chronic hepatitis B (CHB) patients with unsatisfactory curative effect on ADV and compared with routine HBV DNA sequencing.RESULTS: Both the sensitivity and specificity of this new detection approach to ADV-resistant HBV quasispecies were 100%, which were much higher than those of direct HBV DNA sequencing. The approach was able to detect 0.1% of mutated strains in a total plasmid population. Among the 32 clinical patients, single rtA181 and rtN236T mutation and double rtA181T and rtN236T mutations were detected in 20 and 8, respectively, while ADV-resistant mutations in 6 (including, rtA181V/T mutation alone in 5 patients) and no associated mutations in 26.CONCLUSION: This new approach is more feasible and efficient to detect ADV-resistant mutants of HBV and ADV-resistant mutations before and during ADV treatment with a specificity of 100% and a sensitivity of 100%.展开更多
A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT）...A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT） to that of the control line （Ac） was used to effectively minimize interference among strips and sample variations. The linear range for the quantitative detection of RAC was 0.2 ng/mL to 3.5 ng/mL with a median inhibitory concentration （IC50） of 0.59＋0.06 ng/mL. The limit of detection （LOD） of the LFIA was 0.13 ng/mL. The intra-assay recovery rates were 92.97%, 97.25%, and 107.41%, whereas the inter-assay rates were 80.07%, 108.17%, and 93.7%, respectively.展开更多
Objective To research a protein chip method which can simultaneously quantitative detect β-Lactoglobulin （β-L） and Lactoferrin （Lf） at one time. Methods Protein chip printer was used to print both anti-β-L anti...Objective To research a protein chip method which can simultaneously quantitative detect β-Lactoglobulin （β-L） and Lactoferrin （Lf） at one time. Methods Protein chip printer was used to print both anti-β-L antibodies and anti-Lf antibodies on each block of protein chip. And then an improved sandwich detection method was applied while the other two detecting antibodies for the two antigens were added in the block after they were mixed. The detection conditions of the quantitative detection for simultaneous measurement of β-L and Lf with protein chip were optimized and evaluated. Based on these detected conditions, two standard curves of the two proteins were simultaneously established on one protein chip. Finally, the new detection method was evaluated by using the analysis of precision and accuracy. Results By comparison experiment, mouse monoclonal antibodies of the two antigens were chosen as the printing probe. The concentrations of β-L and Lf probes were 0.5 mg/mL and 0.5 mg/mL, respectively, while the titers of detection antibodies both of β-L and Lf were 1：2,000. Intra- and inter-assay variability was between 4.88% and 38.33% for all tests. The regression coefficients of protein chip comparing with ELISA for β-L and Lf were better than 0.734, and both of the two regression coefficients were statistically significant （r = 0.734, t = 2.644, P = 0.038; and r = 0.774, t = 2.998, P = 0.024）. Conclusion A protein chip method of simultaneously quantitative detection for β-L and Lf has been established and this method is worthy in further application.展开更多
At present,many researchers focused on the point-of-care testing（POCT）,a method of disease markers detection without large-scale instruments and specialized persons.However,most POCT diagnostic methods were suffered...At present,many researchers focused on the point-of-care testing（POCT）,a method of disease markers detection without large-scale instruments and specialized persons.However,most POCT diagnostic methods were suffered from poor detection sensitivity or inefficiency in quantitative detection.Herein,we developed a newly QD-immune fluorescence test strips（QD-IFTS） based on quantum dots（QDs） as the fluorescence nanocarrier to prepare the immune fluorescence probes in the classical immunochromatography detection system for sensing carcino-embryonic antigen（CEA）,a kind of glycoprotein produced by intestinal tissue and a broad spectrum of tumor marker for cancer diagnosis.And we designed a homemade strips fluorescence reader for detection of fluorescence intensity of QDs on the QD-IFTS.Under the optimized reaction conditions,chromatographic time of the newly QD-IFTS was only25 min,sample volume of the newly QD-IFTS was only 40 m L and the LOD of the newly QD-IFTS was 0.72 ng/m L.In addition,the efficiency and robustness of the newly QD-IFTS were confirmed by successfully application in 300 clinical serum samples,and the results revealed great potential in clinical POCT of other biomarkers.展开更多
Objective To establish a method for quantitative detection of the sulfate glycosaminoglycans ( GAG) content in extracellular matrix of in vitro cultured chondrocytes so as to evaluate the biological characteristics of...Objective To establish a method for quantitative detection of the sulfate glycosaminoglycans ( GAG) content in extracellular matrix of in vitro cultured chondrocytes so as to evaluate the biological characteristics of epiphyseal, articular and rib chondrocytes. Methods Sulfate GAG content in extracellular matrix of three chondrocytes was measured by the modified dimethylmethylene blue (DMB) method. The changes of the toluidine blue (TB) stain of chondrocytes were observed by light microscope. Results Primary chondrocytes had the highest content of sulfate GAG in the extracellular matrix, ie, epiphyseal chondrocytes reached ( 70. 12 ± 7. 72 )μg/cm2, articular chondrocytes (92.00 ± 10.15) μg/cm2 and rib chondrocytes (80.61 ± 11. 40) μg/cm2, respectively. On the third pasage chondrocytes, epiphyceal chondrocytes decreased to (53.27 ± 9. 50 ) μg/cm2, articular chondrocytes to (63.88 ± 11.92) μg/cm2 and rib chondrocytes to (58.94 ±8.21) μg/cm2, respectively. The change of TB in every passage展开更多
Planetary gear set is the critical component in helicopter transmission train, and an important problem in condition monitoring and health management of planetary gear set is quantitative damage detection. In order to...Planetary gear set is the critical component in helicopter transmission train, and an important problem in condition monitoring and health management of planetary gear set is quantitative damage detection. In order to resolve this problem, an approach based on physical models is presented to detect damage quantitatively in planetary gear set. A particular emphasis is put on a feature generation and selection method, which is used for sun gear tooth breakage damage detection quantitatively in planetary gear box of helicopter transmission system. In this feature generation procedure, the pure torsional dynamical models of 2K-H planetary gear set is established for healthy case and sun gear tooth-breakage case. Then, a feature based on the spectrum of simulation signals of the dynamical models is generated. Aiming at selecting the best feature suitable for quantitative damage detection, a two-sample Z-test procedure is used to analyze the performance of features on damage evolution tracing. A feature named SR, which had better performance in tracking damage, is proposed to detect damage in planetary gear set. Meanwhile, the sun gear tooth-chipped seeded experiments with different severity are designed to validate the method above, and then the test vibration signal is picked up and used for damage detection. With the results of several experiments for quantitative damage detection, the feasibility and the effect of this approach are verified. The proposed method can supply an effective tool for degradation state identification in condition monitoring and health management of helicopter transmission system.展开更多
Rapid and simple detections of two kinds of prohibited fish drugs, crystal violet （CV） and malachite green （MG）, were accomplished by surface-enhanced Raman scattering （SERS）. Based on the optimized Au/cicada wi...Rapid and simple detections of two kinds of prohibited fish drugs, crystal violet （CV） and malachite green （MG）, were accomplished by surface-enhanced Raman scattering （SERS）. Based on the optimized Au/cicada wing, the detectable concentration of CV/MG can reach 10-7 M, and the linear logarithmic quantitative relationship curves between log/and logC allows for the determination of the unknown concentration of CV/MG solution. The detection of these two analytes in real environment was also achieved, demonstrating the application potential of SERS in the fast screening of the prohibited fish drugs, which is of great benefit for food safety and environmental monitoring.展开更多
Norfloxacin is a kind of quinolone bactericide which is widely used in food industry,livestock feed and medicine area.At present,how to develop a rapid,convenient and accurate technique for qualitative and quantitativ...Norfloxacin is a kind of quinolone bactericide which is widely used in food industry,livestock feed and medicine area.At present,how to develop a rapid,convenient and accurate technique for qualitative and quantitative detection of norfloxacin is still a challenge.In this study,Terahertz Time-domain Spectroscopy technology(THz-TDS)was used to explore qualitative and quantitative analysis of norfloxacin.Forty-five norfloxacin samples with different levels were prepared.The pure norfloxacin powder was mixed with polyethylene(PE)powder together and made into tablets by tablet-making machine.The minimum detection concentration was 10%and the maximum detection concentration evaluated in the paper was 90%.Then,terahertz(THz)spectra of each sample were measured on K15 THz-TDS equipment.The multiple linear regressions and the partial least squares regression algorithms were used to establish a model to make quantitative analysis.From the results,two typical fingerprint peaks of norfloxacin in terahertz band were observed at 0.944 THz and 1.206 THz,and the correlation coefficient and the root mean square error of the established model reached 0.9908 and 0.0481,respectively,which showed that the model performed well for the prediction.This preliminary study indicates that THz spectroscopy has great potential for future screening applications to detect the presence of norfloxacin residues in food,livestock feed and medicine industries.展开更多
The technique of SYBR Green-based quantitative real-time reverse transcription polymerase chain reaction(real-time RT-PCR)was applied to quantitative detect a 764 bp nucleotide sequence containing total coat protein(c...The technique of SYBR Green-based quantitative real-time reverse transcription polymerase chain reaction(real-time RT-PCR)was applied to quantitative detect a 764 bp nucleotide sequence containing total coat protein(cp)gene of Cymbidium mosaic virus(CyMV).The plasmid containing the target sequence was constructed to prepare the standard curve and detect the sensitivity.The standard curve was drawn based on the linear relationship between the logarithm(base 10)of the quantity of target sequence and cycle threshold[C(T)].While the concentration of plasmid DNA falling within the range of 2.6×10^(7)to 2.6×10^(2)copies per tube established a regression equation,y=-0.3583x+10.32,and related coefficient:r^(2)=0.995.The real-time RT-PCR assay for CyMV had a minimum detectable quantity of two copies per tube.The naturally infected samples of Phalaenopsis sp.and the artificially inoculated samples of Arachnis sp.with trace CyMV were quantitatively detected using this method.CyMVin the positive samples of Phalaenopsis sp.and Arachnis sp.was confirmed by DNA sequencing and cp gene homeology blast.The results showed that CyMV extracted from the leaves of orchid in Hangzhou,Zhejiang Province,China,could be derived from Kunming city(KM),Yunnan Province,China.This method characterized by high sensitivity,specificity,and precision is suitable for early diagnosis and quantitative detection of CyMV.展开更多
γ-Polyglutamic acid(γ-PGA)is a kind of polymer material with good biocompatibility and degradability,which is widely used in food,medicine,environmental protection,cosmetics and agriculture.Asγ-PGA is produced by m...γ-Polyglutamic acid(γ-PGA)is a kind of polymer material with good biocompatibility and degradability,which is widely used in food,medicine,environmental protection,cosmetics and agriculture.Asγ-PGA is produced by microbial fermentation,its separation,purification and quantitative detection are very important.In this study,the separation methods such as organic solvent precipitation,copper salt precipitation and membrane separation precipitation were mainly discussed,and the quantitative determination methods such as spectrophotometer,enzyme method and viscosity method ofγ-PGA were discussed and compared.Furthermore,Molecular imprinting as a new method for the separation ofγ-PGA has also been analyzed and discussed in order to provide a reference for the separation and purification ofγ-PGA.展开更多
In the present study, dot-blot hybridization, serial dilution analysis and densitomctric scanning were used to detect amplification of proto- oncogenes including c-erbB2, c-myc, int-2 and c-Ha-ras in 104 paraffin-embe...In the present study, dot-blot hybridization, serial dilution analysis and densitomctric scanning were used to detect amplification of proto- oncogenes including c-erbB2, c-myc, int-2 and c-Ha-ras in 104 paraffin-embedded breast cancers. Expression of c-erbB2 was also examined by immunohistochemistry. Amplification of c-erbB2. c-myc and int-2 genes was found in 34.7%, 17.8% and 11.9% of breast cancers respectively. However amplification of c-Ha-ras was not detected in all cases. In 11.9% of cases co-amplification of two or more oncogenes was observed. Positive immunostain-ing of c-erbB2 was seen in 23.8% of the cases and it was significantly associated, but not always corresponding to the amplification of the gene. There was no difference between primary and metastatic breast cancer in the alterations of proto-oncogenes examined in this study, which suggested that the amplification and overexpression of these proto-oncogenes occured prior to and maintained in the process of metastasis of breast cancer. Statistical analysis showed that high-scale of immunopositive staining of c-erbB2 and high-fold co-amplification of proto-oncogenes were significantly correlated with large size of the tumour and the number of involved lymph nodes. Our results indicate that the alterations of multiple oncogenes are involved in the development of breats cancer and some of them may have prognostic importance for breast cancer patients.展开更多
In order to improve the standardized technical system of quantitative analyses for genetically modified organisms( GMOs) and protect China's bio-safety and reduce ecological risk,we establish a quantitative detect...In order to improve the standardized technical system of quantitative analyses for genetically modified organisms( GMOs) and protect China's bio-safety and reduce ecological risk,we establish a quantitative detection method for the genetically modified( GM) maize MON88017 using real-time fluorescent quantitative PCR. Meanwhile,the method is evaluated by several methodological indicators such as specificity,sensitivity,accuracy and uncertainty of measurement. The results show that the method has strong specificity in analysis of genetically modified maize MON88017. The mean value(1. 54%) repeatedly measured for 29 times with the relative deviation of 2. 7% was close to the real value(1. 50%) and the variation coefficient of the measured value was 0. 1. The tested recovery rate is 100% and the uncertainty of measurement is 0. 096. 5 copies of the MON88017 molecular fragment can be detected at 97. 5% confidence level. Consequently,the quantitative detection method established in this paper for the GM maize MON88017 has fairly high specificity,accuracy and sensitivity and this technology established in this paper can provide good technical support for the safety supervision of genetically modified organisms in China.展开更多
Aluminum alloy is widely applied to the aerospace field.However,the inspection of thin plates using Time-of-Flight Diffraction(TOFD)technique is restricted by the near-surface dead zone because of the coupling between...Aluminum alloy is widely applied to the aerospace field.However,the inspection of thin plates using Time-of-Flight Diffraction(TOFD)technique is restricted by the near-surface dead zone because of the coupling between diffracted longitudinal wave and lateral wave.The halfskip mode-converted wave is introduced to decrease dead zone and detect defects in aluminum alloy thin plates by increasing ray path and propagation time.The quantitative correlation for the diffracted shear wave from longitudinal back-wall wave is deduced in combination with the acoustic path,realizing the accurate location of shallow subsurface defects.Simulated and experimental results indicate that the dead zone is decreased by 38% by the half-skip mode-converted wave,and the location errors are within 5% for the aluminum alloy plate with a thickness of 7.0 mm.Compared to other alternative TOFD techniques,half-skip mode-converted wave has better response amplitude and positioning accuracy,demonstrating strong applicability in TOFD inspection of thin plates.展开更多
Dear Editor,Influenza A viruses(IAVs)are single-stranded,negative sense RNA viruses.IAV subtype is determined on the basis of the viral surface glycoproteins,hemagglutinin(HA),and neuraminidase(NA).To date,18 HA and 1...Dear Editor,Influenza A viruses(IAVs)are single-stranded,negative sense RNA viruses.IAV subtype is determined on the basis of the viral surface glycoproteins,hemagglutinin(HA),and neuraminidase(NA).To date,18 HA and 11NA subtypes have been reported(Tong et al.,2012).展开更多
Butyrylcholinesterase(BChE)is a pivotal enzyme that degrades the neurotransmitter acetylcholine,which is related to learning and memory,into choline and acetic acid.BChE activity is strongly associated with various di...Butyrylcholinesterase(BChE)is a pivotal enzyme that degrades the neurotransmitter acetylcholine,which is related to learning and memory,into choline and acetic acid.BChE activity is strongly associated with various diseases,including Alzheimer’s disease,multiple sclerosis,diabetes,and lipid metabolism disorders.It also possesses pharmacological properties for combating cocaine addiction and detoxifying organophosphate poisoning.Given the significant importance of BChE in the biological and medical fields,detecting its activity and understanding its expression in the body are crucial for advancing related research.Herein,a brief review of recently reported specific fluorescence or chemiluminescence probes for quantifying and real-time monitoring BChE is provided.By utilizing unique recognition groups,these probes achieve highly selective identification of BChE and effectively resist interference from other biological factors.Probes demonstrate excellent performance in measuring BChE activity,screening BChE inhibitors,and locating BChE in cells and mice.These also offer strong technical support for early diagnosis,precise intervention,and effective treatment of diseases with pathological changes in BChE.展开更多
During the past decade, great efforts have been made to boost the land use trans- formation in the Loess Plateau, especially for reducing soil erosion by vegetation restoration measures. The Grain-for-Green project （...During the past decade, great efforts have been made to boost the land use trans- formation in the Loess Plateau, especially for reducing soil erosion by vegetation restoration measures. The Grain-for-Green project （GFG） is the largest ecological rehabilitation program in China, which has a positive impact on the vegetation restoration and sustainable devel- opment for the ecologically fragile region of west China. Based on the Landsat TM/ETM im- ages for three time periods （2000, 2005 and 2010）, this study applied the GIS technology and a hill-slope analytical model to reveal the spatio-temporal evolutional patterns of returning slope farmland to grassland or woodland in Baota District, Yan＇an city of Shaanxi province. Results showed that： （1） from 2000 to 2010, the area of farmland decreased by approximately 35,030 ha, which is the greatest decrease among all the land-use types, whereas grassland, woodland and construction land increased, of which grassland expanded rapidly by 26,380 ha （2） The annual variation rate of land-use dynamics was 1.98% during the period 2000-2010, of which the rate was 1.05% for the 2000-2005 period and 2.92% for the 2005-2010 period, respectively. Over the past decade, returning farmland to woodland or pastures was the main source of increased grassland and woodland, and the reduction of farmland contributed to the increase in grassland and woodland by 97.39% and 85.28%, respectively. （3） As the terrain slope increases, farmland decreased and woodland and grassland increased significantly. Areas with a slope ranging from 15° to 25° and less than 15° were the focus of the GFG project, accounting for 85% of the total area of farmland reduction. Meanwhile, the reduction in farmland was significant and spatially correlated with the increase in woodland and grass- land. （4） Between 2000 and 2010, the area of destruction of grass and trees in grasslands and woodlands for the reclamation of farmland was approximately 4596 ha. The area subject to the GFG policy was 4456 ha with a slope greater than 25° over the decade, but the area of farmland was still 10,357 ha in 2010. Our results indicate that there has still a great potential for returning the steep-slope farmlands to woodlands or grasslands in the Loess Plateau.展开更多
基金the National Natural Science Foundation of China(No.12174229 and 22375117)Natural Science Foundation of Shandong Province(No.ZR2022YQ02 and ZR2023MB149)Taishan Scholars Program of Shandong Province(No.tsqn202306152)for financial support.
文摘Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate and introduced a multiplex-feature analysis strategy based on the coffee ring effect.This substrate not only offers high Raman enhancement but also exhibits a high probability of detection(POD),enabling rapid and accurate identification of 50 nm polystyrene nanoplastics over a broad concentration range(1–10−10 wt%).Importantly,experimental results reveal a strong correlation between the coffee ring formation and the concentration of nanoplastic dispersion.By incorporating Raman signal intensity,coffee ring diameter,and POD as combined features,we established a machine learning-based mapping between nanoplastic concentration and coffee ring characteristics,allowing precise predictions of dispersion concentration.The mean squared error of these predictions is remarkably low,ranging from 0.21 to 0.54,representing a 19 fold improvement in accuracy compared to traditional linear regression-based methods.This strategy effectively integrates SERS with wettability modification techniques,ensuring high sensitivity and fingerprinting capabilities,while addressing the limitations of Raman signal intensity in accurately reflecting concentration changes at ultra-low levels,providing a new idea for precise SERS measurements of nanoplastics.
基金supported by National Natural Science Foundation of China(Grant No.:32301161)the Natural Scientific Foundation of Hunan Province,China(Grant No.:2023JJ60052)+3 种基金the Scientific Research Project of Hunan Provincial Health Commission,China(Grant No.:202112062218,20190161)the Scientific Research Project of Hunan Provincial Department of Education,China(Grant No.:22B0455)the Clinical“4310”Project of the University of South China,China(Grant No.:20224310NHYCG02)the Doctoral Scientific Research Foundation of University of South China,China(Grant No.:200XQD042).
文摘Infrared(IR)spectroscopy,a technique within the realm of molecular vibrational spectroscopy,furnishes distinctive chemical signatures pivotal for both structural analysis and compound identification.A notable challenge emerges from the misalignment between the mid-IR light wavelength range and molecular dimensions,culminating in a constrained absorption cross-section and diminished vibrational absorption coefficients(Supplementary data).
基金Supported by The National Project for the Prevention and Control of Major Exotic Animal Diseases(2022YFD1800500)National Mutton Sheep Industrial Technology System(CARS39).
文摘[Objectives]This study was conducted to establish a rapid quantitative method for detecting antibody against Peste des Petits Ruminants Virus(PPR V)in sheep serum.[Methods]Soluble N protein and NH fusion protein were obtained in Escherichia coli prokaryotic expression system by optimizing codons and expression conditions of E.coli.Furthermore,based on the purified soluble N protein and NH fusion protein,a high-sensitivity fluorescence immunoassay kit for detecting the antibody against PPR V was established.[Results]The method could quickly and quantitatively detect PPR V antibody in sheep serum,with high sensitivity and specificity,without any cross reaction to other related sheep pathogens.The intra-batch and inter-batch coefficients of variation were less than 10%and 15%,respectively,and the method had good repeatability.Through detection on 292 clinical serum samples,it was compared with the French IDVET competitive ELISA kit,and the coincidence rate of the two methods reached 93.84%.Compared with the serum neutralization test,the detected titer value of the high-sensitivity rapid fluorescence quantitative detection method was basically consistent with the tilter value obtained by the neutralization test on the standard positive serum(provided by the WOAH Brucellosis Reference Laboratory of France).[Conclusions]This method can realize rapid quantitative detection of PPR V antibody on site,and has high practical value and popularization value.
文摘Objective Shellfish are recognized as important vehicles of norovirus-associated gastroenteritis. The present study aimed to monitor norovirus contamination in oysters along the farm-to-fork continuum in Guangxi, a major oyster production area in Southwestern China. Methods Oyster samples were collected monthly from farms, markets, and restaurants, from January to December 2016. Norovirus was detected and quantified by one-step reverse transcription-droplet digital polymerase chain reaction（RT-ddPCR）. Results A total of 480 oyster samples were collected and tested for norovirus genogroups I and II. Norovirus was detected in 20.7% of samples, with genogroup II predominating. No significant difference was observed in norovirus prevalence among different sampling sites. The norovirus levels varied widely, with a geometric mean of 19,300 copies/g in digestive glands. Both norovirus prevalence and viral loads showed obvious seasonality, with a strong winter bias. Conclusion This study provides a systematic analysis of norovirus contamination ‘from the farm to the fork＇ in Guangxi. RT-ddPCR can be a useful tool for detection and quantification of low amounts of norovirus in the presence of inhibitors found particularly in foodstuffs. This approach will contribute to the development of strategies for controlling and reducing the risk of human illness resulting from shellfish consumption.
基金Supported by The fund from Health Project of Jiangsu Province,No.H200711the AIDS,Hepatitis B and Other Infectious Diseases Prevention Program,No.2009ZX10004-712
文摘AIM:To establish the more feasible and sensitive assessment approach to the detection of adefovir (ADV) resistance-associated hepatitis B virus (HBV) quasispecies.METHODS: Based on the characteristics of rtA181V/T and rtN236T mutations, a new approach based on real-time fluorescent quantitative polymerase chain reaction (RT-PCR) was established for the detection of ADV-resistant HBV quasispecies, total HBV DNA, rtA181 and rtN236 mutations in blood samples from 32 chronic hepatitis B (CHB) patients with unsatisfactory curative effect on ADV and compared with routine HBV DNA sequencing.RESULTS: Both the sensitivity and specificity of this new detection approach to ADV-resistant HBV quasispecies were 100%, which were much higher than those of direct HBV DNA sequencing. The approach was able to detect 0.1% of mutated strains in a total plasmid population. Among the 32 clinical patients, single rtA181 and rtN236T mutation and double rtA181T and rtN236T mutations were detected in 20 and 8, respectively, while ADV-resistant mutations in 6 (including, rtA181V/T mutation alone in 5 patients) and no associated mutations in 26.CONCLUSION: This new approach is more feasible and efficient to detect ADV-resistant mutants of HBV and ADV-resistant mutations before and during ADV treatment with a specificity of 100% and a sensitivity of 100%.
基金supported by the national science and technology support program in the 12th Five Year Plan(2011BAK10B04 and 2011BAK10B01)the national natural science foundation of China(Grant No.31160323)the research program of the state key laboratory of food science and technology,Nanchang University(SKLF-ZZB-201306)
文摘A strip reader based lateral flow immunoassay （LFIA） was established for the rapid and quantitative detection of ractopamine （RAC） in swine urine. The ratio of the optical densities （ODs） of the test line （AT） to that of the control line （Ac） was used to effectively minimize interference among strips and sample variations. The linear range for the quantitative detection of RAC was 0.2 ng/mL to 3.5 ng/mL with a median inhibitory concentration （IC50） of 0.59＋0.06 ng/mL. The limit of detection （LOD） of the LFIA was 0.13 ng/mL. The intra-assay recovery rates were 92.97%, 97.25%, and 107.41%, whereas the inter-assay rates were 80.07%, 108.17%, and 93.7%, respectively.
基金Sponsored by the Young Scholar Scientific Research Foundation of China CDC[2015A202]:The establishment of testing platform of quantitatively detecting main protein of cow milk by using protein chip technique
文摘Objective To research a protein chip method which can simultaneously quantitative detect β-Lactoglobulin （β-L） and Lactoferrin （Lf） at one time. Methods Protein chip printer was used to print both anti-β-L antibodies and anti-Lf antibodies on each block of protein chip. And then an improved sandwich detection method was applied while the other two detecting antibodies for the two antigens were added in the block after they were mixed. The detection conditions of the quantitative detection for simultaneous measurement of β-L and Lf with protein chip were optimized and evaluated. Based on these detected conditions, two standard curves of the two proteins were simultaneously established on one protein chip. Finally, the new detection method was evaluated by using the analysis of precision and accuracy. Results By comparison experiment, mouse monoclonal antibodies of the two antigens were chosen as the printing probe. The concentrations of β-L and Lf probes were 0.5 mg/mL and 0.5 mg/mL, respectively, while the titers of detection antibodies both of β-L and Lf were 1：2,000. Intra- and inter-assay variability was between 4.88% and 38.33% for all tests. The regression coefficients of protein chip comparing with ELISA for β-L and Lf were better than 0.734, and both of the two regression coefficients were statistically significant （r = 0.734, t = 2.644, P = 0.038; and r = 0.774, t = 2.998, P = 0.024）. Conclusion A protein chip method of simultaneously quantitative detection for β-L and Lf has been established and this method is worthy in further application.
基金financially supported by the National Natural Science Foundation of China(Nos.51373117,51303126 and 31600800)Tianjin Natural Science and Technology Foundation(No.16ZXMJSY00010)
文摘At present,many researchers focused on the point-of-care testing（POCT）,a method of disease markers detection without large-scale instruments and specialized persons.However,most POCT diagnostic methods were suffered from poor detection sensitivity or inefficiency in quantitative detection.Herein,we developed a newly QD-immune fluorescence test strips（QD-IFTS） based on quantum dots（QDs） as the fluorescence nanocarrier to prepare the immune fluorescence probes in the classical immunochromatography detection system for sensing carcino-embryonic antigen（CEA）,a kind of glycoprotein produced by intestinal tissue and a broad spectrum of tumor marker for cancer diagnosis.And we designed a homemade strips fluorescence reader for detection of fluorescence intensity of QDs on the QD-IFTS.Under the optimized reaction conditions,chromatographic time of the newly QD-IFTS was only25 min,sample volume of the newly QD-IFTS was only 40 m L and the LOD of the newly QD-IFTS was 0.72 ng/m L.In addition,the efficiency and robustness of the newly QD-IFTS were confirmed by successfully application in 300 clinical serum samples,and the results revealed great potential in clinical POCT of other biomarkers.
文摘Objective To establish a method for quantitative detection of the sulfate glycosaminoglycans ( GAG) content in extracellular matrix of in vitro cultured chondrocytes so as to evaluate the biological characteristics of epiphyseal, articular and rib chondrocytes. Methods Sulfate GAG content in extracellular matrix of three chondrocytes was measured by the modified dimethylmethylene blue (DMB) method. The changes of the toluidine blue (TB) stain of chondrocytes were observed by light microscope. Results Primary chondrocytes had the highest content of sulfate GAG in the extracellular matrix, ie, epiphyseal chondrocytes reached ( 70. 12 ± 7. 72 )μg/cm2, articular chondrocytes (92.00 ± 10.15) μg/cm2 and rib chondrocytes (80.61 ± 11. 40) μg/cm2, respectively. On the third pasage chondrocytes, epiphyceal chondrocytes decreased to (53.27 ± 9. 50 ) μg/cm2, articular chondrocytes to (63.88 ± 11.92) μg/cm2 and rib chondrocytes to (58.94 ±8.21) μg/cm2, respectively. The change of TB in every passage
基金supported by National Natural Science Foundation of China (Grant No. 50905183)
文摘Planetary gear set is the critical component in helicopter transmission train, and an important problem in condition monitoring and health management of planetary gear set is quantitative damage detection. In order to resolve this problem, an approach based on physical models is presented to detect damage quantitatively in planetary gear set. A particular emphasis is put on a feature generation and selection method, which is used for sun gear tooth breakage damage detection quantitatively in planetary gear box of helicopter transmission system. In this feature generation procedure, the pure torsional dynamical models of 2K-H planetary gear set is established for healthy case and sun gear tooth-breakage case. Then, a feature based on the spectrum of simulation signals of the dynamical models is generated. Aiming at selecting the best feature suitable for quantitative damage detection, a two-sample Z-test procedure is used to analyze the performance of features on damage evolution tracing. A feature named SR, which had better performance in tracking damage, is proposed to detect damage in planetary gear set. Meanwhile, the sun gear tooth-chipped seeded experiments with different severity are designed to validate the method above, and then the test vibration signal is picked up and used for damage detection. With the results of several experiments for quantitative damage detection, the feasibility and the effect of this approach are verified. The proposed method can supply an effective tool for degradation state identification in condition monitoring and health management of helicopter transmission system.
基金Project supported by the National Basic Research Program of China(Grant No.2014CB745100)the National Natural Science Foundation of China(Grant Nos.21390202 and 21676015)the Beijing Higher Education Young Elite Teacher Project
文摘Rapid and simple detections of two kinds of prohibited fish drugs, crystal violet （CV） and malachite green （MG）, were accomplished by surface-enhanced Raman scattering （SERS）. Based on the optimized Au/cicada wing, the detectable concentration of CV/MG can reach 10-7 M, and the linear logarithmic quantitative relationship curves between log/and logC allows for the determination of the unknown concentration of CV/MG solution. The detection of these two analytes in real environment was also achieved, demonstrating the application potential of SERS in the fast screening of the prohibited fish drugs, which is of great benefit for food safety and environmental monitoring.
基金supported by the“Thirteenth Five-Year”National Key Research and Development Program of China(No.2016YFD0702002)the International Cooperation Fund of Beijing Academy of Agriculture and Forestry Sciences(GJHZ2017-7).
文摘Norfloxacin is a kind of quinolone bactericide which is widely used in food industry,livestock feed and medicine area.At present,how to develop a rapid,convenient and accurate technique for qualitative and quantitative detection of norfloxacin is still a challenge.In this study,Terahertz Time-domain Spectroscopy technology(THz-TDS)was used to explore qualitative and quantitative analysis of norfloxacin.Forty-five norfloxacin samples with different levels were prepared.The pure norfloxacin powder was mixed with polyethylene(PE)powder together and made into tablets by tablet-making machine.The minimum detection concentration was 10%and the maximum detection concentration evaluated in the paper was 90%.Then,terahertz(THz)spectra of each sample were measured on K15 THz-TDS equipment.The multiple linear regressions and the partial least squares regression algorithms were used to establish a model to make quantitative analysis.From the results,two typical fingerprint peaks of norfloxacin in terahertz band were observed at 0.944 THz and 1.206 THz,and the correlation coefficient and the root mean square error of the established model reached 0.9908 and 0.0481,respectively,which showed that the model performed well for the prediction.This preliminary study indicates that THz spectroscopy has great potential for future screening applications to detect the presence of norfloxacin residues in food,livestock feed and medicine industries.
文摘The technique of SYBR Green-based quantitative real-time reverse transcription polymerase chain reaction(real-time RT-PCR)was applied to quantitative detect a 764 bp nucleotide sequence containing total coat protein(cp)gene of Cymbidium mosaic virus(CyMV).The plasmid containing the target sequence was constructed to prepare the standard curve and detect the sensitivity.The standard curve was drawn based on the linear relationship between the logarithm(base 10)of the quantity of target sequence and cycle threshold[C(T)].While the concentration of plasmid DNA falling within the range of 2.6×10^(7)to 2.6×10^(2)copies per tube established a regression equation,y=-0.3583x+10.32,and related coefficient:r^(2)=0.995.The real-time RT-PCR assay for CyMV had a minimum detectable quantity of two copies per tube.The naturally infected samples of Phalaenopsis sp.and the artificially inoculated samples of Arachnis sp.with trace CyMV were quantitatively detected using this method.CyMVin the positive samples of Phalaenopsis sp.and Arachnis sp.was confirmed by DNA sequencing and cp gene homeology blast.The results showed that CyMV extracted from the leaves of orchid in Hangzhou,Zhejiang Province,China,could be derived from Kunming city(KM),Yunnan Province,China.This method characterized by high sensitivity,specificity,and precision is suitable for early diagnosis and quantitative detection of CyMV.
文摘γ-Polyglutamic acid(γ-PGA)is a kind of polymer material with good biocompatibility and degradability,which is widely used in food,medicine,environmental protection,cosmetics and agriculture.Asγ-PGA is produced by microbial fermentation,its separation,purification and quantitative detection are very important.In this study,the separation methods such as organic solvent precipitation,copper salt precipitation and membrane separation precipitation were mainly discussed,and the quantitative determination methods such as spectrophotometer,enzyme method and viscosity method ofγ-PGA were discussed and compared.Furthermore,Molecular imprinting as a new method for the separation ofγ-PGA has also been analyzed and discussed in order to provide a reference for the separation and purification ofγ-PGA.
文摘In the present study, dot-blot hybridization, serial dilution analysis and densitomctric scanning were used to detect amplification of proto- oncogenes including c-erbB2, c-myc, int-2 and c-Ha-ras in 104 paraffin-embedded breast cancers. Expression of c-erbB2 was also examined by immunohistochemistry. Amplification of c-erbB2. c-myc and int-2 genes was found in 34.7%, 17.8% and 11.9% of breast cancers respectively. However amplification of c-Ha-ras was not detected in all cases. In 11.9% of cases co-amplification of two or more oncogenes was observed. Positive immunostain-ing of c-erbB2 was seen in 23.8% of the cases and it was significantly associated, but not always corresponding to the amplification of the gene. There was no difference between primary and metastatic breast cancer in the alterations of proto-oncogenes examined in this study, which suggested that the amplification and overexpression of these proto-oncogenes occured prior to and maintained in the process of metastasis of breast cancer. Statistical analysis showed that high-scale of immunopositive staining of c-erbB2 and high-fold co-amplification of proto-oncogenes were significantly correlated with large size of the tumour and the number of involved lymph nodes. Our results indicate that the alterations of multiple oncogenes are involved in the development of breats cancer and some of them may have prognostic importance for breast cancer patients.
基金Supported by Standardization System Research Project of Sichuan Provincial Bureau of Quality Supervision(ZYBZ2013-39)
文摘In order to improve the standardized technical system of quantitative analyses for genetically modified organisms( GMOs) and protect China's bio-safety and reduce ecological risk,we establish a quantitative detection method for the genetically modified( GM) maize MON88017 using real-time fluorescent quantitative PCR. Meanwhile,the method is evaluated by several methodological indicators such as specificity,sensitivity,accuracy and uncertainty of measurement. The results show that the method has strong specificity in analysis of genetically modified maize MON88017. The mean value(1. 54%) repeatedly measured for 29 times with the relative deviation of 2. 7% was close to the real value(1. 50%) and the variation coefficient of the measured value was 0. 1. The tested recovery rate is 100% and the uncertainty of measurement is 0. 096. 5 copies of the MON88017 molecular fragment can be detected at 97. 5% confidence level. Consequently,the quantitative detection method established in this paper for the GM maize MON88017 has fairly high specificity,accuracy and sensitivity and this technology established in this paper can provide good technical support for the safety supervision of genetically modified organisms in China.
基金supported by the National Key Research and Development Program of China(No.2019YFA0709003)the National Natural Science Foundation of China(Nos.52275520 and 51775087).
文摘Aluminum alloy is widely applied to the aerospace field.However,the inspection of thin plates using Time-of-Flight Diffraction(TOFD)technique is restricted by the near-surface dead zone because of the coupling between diffracted longitudinal wave and lateral wave.The halfskip mode-converted wave is introduced to decrease dead zone and detect defects in aluminum alloy thin plates by increasing ray path and propagation time.The quantitative correlation for the diffracted shear wave from longitudinal back-wall wave is deduced in combination with the acoustic path,realizing the accurate location of shallow subsurface defects.Simulated and experimental results indicate that the dead zone is decreased by 38% by the half-skip mode-converted wave,and the location errors are within 5% for the aluminum alloy plate with a thickness of 7.0 mm.Compared to other alternative TOFD techniques,half-skip mode-converted wave has better response amplitude and positioning accuracy,demonstrating strong applicability in TOFD inspection of thin plates.
基金partially supported by the National Institutes of Health(grant no.P20GM103646)the United States Department of Agriculture Animal and Plant Health Inspection Service(agreement 14-7428-1041-CA)
文摘Dear Editor,Influenza A viruses(IAVs)are single-stranded,negative sense RNA viruses.IAV subtype is determined on the basis of the viral surface glycoproteins,hemagglutinin(HA),and neuraminidase(NA).To date,18 HA and 11NA subtypes have been reported(Tong et al.,2012).
基金financial support from the National Natural Science Foundation of China(Nos.82173652 and 81872728)the Natural Science Foundation of Jiangsu Province(No.BK20221522)+1 种基金Support from Jiangsu“333 High Level Talents Cultivation”Leading Talents(No.2022-3-16-203)the Qing Lan Project is also appreciated.
文摘Butyrylcholinesterase(BChE)is a pivotal enzyme that degrades the neurotransmitter acetylcholine,which is related to learning and memory,into choline and acetic acid.BChE activity is strongly associated with various diseases,including Alzheimer’s disease,multiple sclerosis,diabetes,and lipid metabolism disorders.It also possesses pharmacological properties for combating cocaine addiction and detoxifying organophosphate poisoning.Given the significant importance of BChE in the biological and medical fields,detecting its activity and understanding its expression in the body are crucial for advancing related research.Herein,a brief review of recently reported specific fluorescence or chemiluminescence probes for quantifying and real-time monitoring BChE is provided.By utilizing unique recognition groups,these probes achieve highly selective identification of BChE and effectively resist interference from other biological factors.Probes demonstrate excellent performance in measuring BChE activity,screening BChE inhibitors,and locating BChE in cells and mice.These also offer strong technical support for early diagnosis,precise intervention,and effective treatment of diseases with pathological changes in BChE.
基金Foundation： National Natural Science Foundation of China, No.41130748
文摘During the past decade, great efforts have been made to boost the land use trans- formation in the Loess Plateau, especially for reducing soil erosion by vegetation restoration measures. The Grain-for-Green project （GFG） is the largest ecological rehabilitation program in China, which has a positive impact on the vegetation restoration and sustainable devel- opment for the ecologically fragile region of west China. Based on the Landsat TM/ETM im- ages for three time periods （2000, 2005 and 2010）, this study applied the GIS technology and a hill-slope analytical model to reveal the spatio-temporal evolutional patterns of returning slope farmland to grassland or woodland in Baota District, Yan＇an city of Shaanxi province. Results showed that： （1） from 2000 to 2010, the area of farmland decreased by approximately 35,030 ha, which is the greatest decrease among all the land-use types, whereas grassland, woodland and construction land increased, of which grassland expanded rapidly by 26,380 ha （2） The annual variation rate of land-use dynamics was 1.98% during the period 2000-2010, of which the rate was 1.05% for the 2000-2005 period and 2.92% for the 2005-2010 period, respectively. Over the past decade, returning farmland to woodland or pastures was the main source of increased grassland and woodland, and the reduction of farmland contributed to the increase in grassland and woodland by 97.39% and 85.28%, respectively. （3） As the terrain slope increases, farmland decreased and woodland and grassland increased significantly. Areas with a slope ranging from 15° to 25° and less than 15° were the focus of the GFG project, accounting for 85% of the total area of farmland reduction. Meanwhile, the reduction in farmland was significant and spatially correlated with the increase in woodland and grass- land. （4） Between 2000 and 2010, the area of destruction of grass and trees in grasslands and woodlands for the reclamation of farmland was approximately 4596 ha. The area subject to the GFG policy was 4456 ha with a slope greater than 25° over the decade, but the area of farmland was still 10,357 ha in 2010. Our results indicate that there has still a great potential for returning the steep-slope farmlands to woodlands or grasslands in the Loess Plateau.
