期刊文献+
共找到6,321篇文章
< 1 2 250 >
每页显示 20 50 100
Multi-Compartment SCFA Quantification in Human
1
作者 Jérémy Monteiro Antoine Lefèvre +6 位作者 Diane Dufour-Rainfray Adeline Oury Gabrielle Chicheri Laurent Galineau Hélène Blasco Lydie Nadal-Desbarats Patrick Emond 《American Journal of Analytical Chemistry》 CAS 2024年第6期177-200,共24页
Short-chain fatty acids (SCFA) play an important role in human biochemistry. They originate primarily from the digestive system through carbohydrates microbial fermentation. Most SCFA produced in the colon are absorbe... Short-chain fatty acids (SCFA) play an important role in human biochemistry. They originate primarily from the digestive system through carbohydrates microbial fermentation. Most SCFA produced in the colon are absorbed by the intestinal wall and enter the bloodstream to be distributed throughout the body for multiple purposes. At the intestinal level, SCFA play a role in controlling fat storage and fatty acid metabolism. The effects of these beneficial compounds therefore concern overall health. They facilitate energy expenditure and are valuable allies in the fight against obesity and diabetes. SCFA are also involved in the regulation of the levels of several neurotransmitters such as GABA (γ-aminobutyric acid), glutamate, serotonin, dopamine, and norepinephrine. Their role is also highlighted in many inflammatory and neurodegenerative diseases such as Alzheimer’s disease (AD) or Parkinson’s disease (PD). To have a realistic picture of the distribution of SCFA in different biological compartments of the human body, we propose to study SCFA simultaneously in five human biological samples: feces, saliva, serum, cerebrospinal fluid (CSF), and urine, as well as in Dried Blood Spot (DBS). To evaluate their concentration and repeatability, we used 10 aliquots from pooled samples, analyzed by 3-nitrophenylhydrazine (3-NPH) derivation and liquid chromatography coupled with high sensitivity mass spectrometry (LC-QqQ-MS). We also evaluated the SCFA assay on Dried Blood Spot (DBS). In this work, we adapted the pre-analytical parts for each sample to be able to use a common calibration curve, thus facilitating multi-assay quantification studies and so being less time-consuming. Moreover, we proposed new daughter ions from the same neutral loss (43 Da) to quantify SCFAs, thus improving the sensitivity. In conclusion, our methodology, based on a unique calibration curve for all samples for each SCFA, is well-suited to quantified them in a clinical context. 展开更多
关键词 LC-MS 3-Nitrophenylhydrazine Short-Chain Fatty Acids Human Biological Samples quantification
下载PDF
Investigation on mechanical properties regulation of rock-like specimens based on 3D printing and similarity quantification
2
作者 Duanyang Zhuang Zexu Ning +3 位作者 Yunmin Chen Jinlong Li Qingdong Li Wenjie Xu 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第5期573-585,共13页
3D printing is widely adopted to quickly produce rock mass models with complex structures in batches,improving the consistency and repeatability of physical modeling.It is necessary to regulate the mechanical properti... 3D printing is widely adopted to quickly produce rock mass models with complex structures in batches,improving the consistency and repeatability of physical modeling.It is necessary to regulate the mechanical properties of 3D-printed specimens to make them proportionally similar to natural rocks.This study investigates mechanical properties of 3D-printed rock analogues prepared by furan resin-bonded silica sand particles.The mechanical property regulation of 3D-printed specimens is realized through quantifying its similarity to sandstone,so that analogous deformation characteristics and failure mode are acquired.Considering similarity conversion,uniaxial compressive strength,cohesion and stress–strain relationship curve of 3D-printed specimen are similar to those of sandstone.In the study ranges,the strength of 3D-printed specimen is positively correlated with the additive content,negatively correlated with the sand particle size,and first increases then decreases with the increase of curing temperature.The regulation scheme with optimal similarity quantification index,that is the sand type of 70/140,additive content of 2.5‰and curing temperature of 81.6℃,is determined for preparing 3D-printed sandstone analogues and models.The effectiveness of mechanical property regulation is proved through uniaxial compression contrast tests.This study provides a reference for preparing rock-like specimens and engineering models using 3D printing technology. 展开更多
关键词 3D printing Mechanical property regulation Similarity quantification Rock analogue SANDSTONE
下载PDF
Uncertainty quantification of inverse analysis for geomaterials using probabilistic programming
3
作者 Hongbo Zhao Shaojun Li +3 位作者 Xiaoyu Zang Xinyi Liu Lin Zhang Jiaolong Ren 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第3期895-908,共14页
Uncertainty is an essentially challenging for safe construction and long-term stability of geotechnical engineering.The inverse analysis is commonly utilized to determine the physico-mechanical parameters.However,conv... Uncertainty is an essentially challenging for safe construction and long-term stability of geotechnical engineering.The inverse analysis is commonly utilized to determine the physico-mechanical parameters.However,conventional inverse analysis cannot deal with uncertainty in geotechnical and geological systems.In this study,a framework was developed to evaluate and quantify uncertainty in inverse analysis based on the reduced-order model(ROM)and probabilistic programming.The ROM was utilized to capture the mechanical and deformation properties of surrounding rock mass in geomechanical problems.Probabilistic programming was employed to evaluate uncertainty during construction in geotechnical engineering.A circular tunnel was then used to illustrate the proposed framework using analytical and numerical solution.The results show that the geomechanical parameters and associated uncertainty can be properly obtained and the proposed framework can capture the mechanical behaviors under uncertainty.Then,a slope case was employed to demonstrate the performance of the developed framework.The results prove that the proposed framework provides a scientific,feasible,and effective tool to characterize the properties and physical mechanism of geomaterials under uncertainty in geotechnical engineering problems. 展开更多
关键词 Geological engineering Geotechnical engineering Inverse analysis Uncertainty quantification Probabilistic programming
下载PDF
High-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer based on probability density evolution method
4
作者 Mingming Wang Linfang Qian +3 位作者 Guangsong Chen Tong Lin Junfei Shi Shijie Zhou 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期209-221,共13页
This paper proposed an efficient research method for high-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer.Firstly,the dynamic model of projectile motion is establi... This paper proposed an efficient research method for high-dimensional uncertainty quantification of projectile motion in the barrel of a truck-mounted howitzer.Firstly,the dynamic model of projectile motion is established considering the flexible deformation of the barrel and the interaction between the projectile and the barrel.Subsequently,the accuracy of the dynamic model is verified based on the external ballistic projectile attitude test platform.Furthermore,the probability density evolution method(PDEM)is developed to high-dimensional uncertainty quantification of projectile motion.The engineering example highlights the results of the proposed method are consistent with the results obtained by the Monte Carlo Simulation(MCS).Finally,the influence of parameter uncertainty on the projectile disturbance at muzzle under different working conditions is analyzed.The results show that the disturbance of the pitch angular,pitch angular velocity and pitch angular of velocity decreases with the increase of launching angle,and the random parameter ranges of both the projectile and coupling model have similar influence on the disturbance of projectile angular motion at muzzle. 展开更多
关键词 Truck-mounted howitzer Projectile motion Uncertainty quantification Probability density evolution method
下载PDF
Uncertainty quantification of mechanism motion based on coupled mechanism—motor dynamic model for ammunition delivery system
5
作者 Jinsong Tang Linfang Qian +3 位作者 Longmiao Chen Guangsong Chen Mingming Wang Guangzu Zhou 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期125-133,共9页
In this paper,a dynamic modeling method of motor driven electromechanical system is presented,and the uncertainty quantification of mechanism motion is investigated based on this method.The main contribution is to pro... In this paper,a dynamic modeling method of motor driven electromechanical system is presented,and the uncertainty quantification of mechanism motion is investigated based on this method.The main contribution is to propose a novel mechanism-motor coupling dynamic modeling method,in which the relationship between mechanism motion and motor rotation is established according to the geometric coordination of the system.The advantages of this include establishing intuitive coupling between the mechanism and motor,facilitating the discussion for the influence of both mechanical and electrical parameters on the mechanism,and enabling dynamic simulation with controller to take the randomness of the electric load into account.Dynamic simulation considering feedback control of ammunition delivery system is carried out,and the feasibility of the model is verified experimentally.Based on probability density evolution theory,we comprehensively discuss the effects of system parameters on mechanism motion from the perspective of uncertainty quantization.Our work can not only provide guidance for engineering design of ammunition delivery mechanism,but also provide theoretical support for modeling and uncertainty quantification research of mechatronics system. 展开更多
关键词 Ammunition delivery system Electromechanical coupling dynamics Uncertainty quantification Generalized probability density evolution
下载PDF
Quantification of the concrete freeze–thaw environment across the Qinghai–Tibet Plateau based on machine learning algorithms
6
作者 QIN Yanhui MA Haoyuan +3 位作者 ZHANG Lele YIN Jinshuai ZHENG Xionghui LI Shuo 《Journal of Mountain Science》 SCIE CSCD 2024年第1期322-334,共13页
The reasonable quantification of the concrete freezing environment on the Qinghai–Tibet Plateau(QTP) is the primary issue in frost resistant concrete design, which is one of the challenges that the QTP engineering ma... The reasonable quantification of the concrete freezing environment on the Qinghai–Tibet Plateau(QTP) is the primary issue in frost resistant concrete design, which is one of the challenges that the QTP engineering managers should take into account. In this paper, we propose a more realistic method to calculate the number of concrete freeze–thaw cycles(NFTCs) on the QTP. The calculated results show that the NFTCs increase as the altitude of the meteorological station increases with the average NFTCs being 208.7. Four machine learning methods, i.e., the random forest(RF) model, generalized boosting method(GBM), generalized linear model(GLM), and generalized additive model(GAM), are used to fit the NFTCs. The root mean square error(RMSE) values of the RF, GBM, GLM, and GAM are 32.3, 4.3, 247.9, and 161.3, respectively. The R^(2) values of the RF, GBM, GLM, and GAM are 0.93, 0.99, 0.48, and 0.66, respectively. The GBM method performs the best compared to the other three methods, which was shown by the results of RMSE and R^(2) values. The quantitative results from the GBM method indicate that the lowest, medium, and highest NFTC values are distributed in the northern, central, and southern parts of the QTP, respectively. The annual NFTCs in the QTP region are mainly concentrated at 160 and above, and the average NFTCs is 200 across the QTP. Our results can provide scientific guidance and a theoretical basis for the freezing resistance design of concrete in various projects on the QTP. 展开更多
关键词 Freeze–thaw cycles quantification Machine learning algorithms Qinghai–Tibet Plateau CONCRETE
下载PDF
Revolutionizing disease diagnosis and management:Open-access magnetic resonance imaging datasets a challenge for artificial intelligence driven liver iron quantification
7
作者 Jaber H Jaradat Abdulqadir J Nashwan 《World Journal of Clinical Cases》 SCIE 2024年第17期2921-2924,共4页
Artificial intelligence(AI),particularly machine learning(ML)and deep learning(DL)techniques,such as convolutional neural networks(CNNs),have emerged as transformative technologies with vast potential in healthcare.Bo... Artificial intelligence(AI),particularly machine learning(ML)and deep learning(DL)techniques,such as convolutional neural networks(CNNs),have emerged as transformative technologies with vast potential in healthcare.Body iron load is usually assessed using slightly invasive blood tests(serum ferritin,serum iron,and serum transferrin).Serum ferritin is widely used to assess body iron and drive medical management;however,it is an acute phase reactant protein offering wrong interpretation in the setting of inflammation and distressed patients.Magnetic resonance imaging is a non-invasive technique that can be used to assess liver iron.The ML and DL algorithms can be used to enhance the detection of minor changes.However,a lack of open-access datasets may delay the advancement of medical research in this field.In this letter,we highlight the importance of standardized datasets for advancing AI and CNNs in medical imaging.Despite the current limitations,embracing AI and CNNs holds promise in revolutionizing disease diagnosis and treatment. 展开更多
关键词 Liver diseases Magnetic resonance imaging Iron quantification Machine learning Deep learning
下载PDF
Progress and prediction of multicomponent quantification in complex systems with practical LC-UV methods 被引量:1
8
作者 Xi Chen Zhao Yang +4 位作者 Yang Xu Zhe Liu Yanfang Liu Yuntao Dai Shilin Chen 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2023年第2期142-155,共14页
Complex systems exist widely,including medicines from natural products,functional foods,and biological samples.The biological activity of complex systems is often the result of the synergistic effect of multiple compo... Complex systems exist widely,including medicines from natural products,functional foods,and biological samples.The biological activity of complex systems is often the result of the synergistic effect of multiple components.In the quality evaluation of complex samples,multicomponent quantitative analysis(MCQA)is usually needed.To overcome the difficulty in obtaining standard products,scholars have proposed achieving MCQA through the“single standard to determine multiple components(SSDMC)”approach.This method has been used in the determination of multicomponent content in natural source drugs and the analysis of impurities in chemical drugs and has been included in the Chinese Pharmacopoeia.Depending on a convenient(ultra)high-performance liquid chromatography method,how can the repeatability and robustness of the MCQA method be improved?How can the chromatography conditions be optimized to improve the number of quantitative components?How can computer software technology be introduced to improve the efficiency of multicomponent analysis(MCA)?These are the key problems that remain to be solved in practical MCQA.First,this review article summarizes the calculation methods of relative correction factors in the SSDMC approach in the past five years,as well as the method robustness and accuracy evaluation.Second,it also summarizes methods to improve peak capacity and quantitative accuracy in MCA,including column selection and twodimensional chromatographic analysis technology.Finally,computer software technologies for predicting chromatographic conditions and analytical parameters are introduced,which provides an idea for intelligent method development in MCA.This paper aims to provide methodological ideas for the improvement of complex system analysis,especially MCQA. 展开更多
关键词 Multicomponent quantification analysis Single standard to determine multiple components Predictive software
下载PDF
Molecular diagnosis and direct quantification of cereal cyst nematode(Heterodera filipjevi) from field soil using TaqMan real-time PCR
9
作者 JIAN Jin-zhuo HUANG Wen-kun +4 位作者 KONG Ling-an JIAN Heng Sulaiman ABDULSALAM PENG De-liang PENG Huan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第8期2591-2601,共11页
Heterodera filipjevi continues to be a major threat to wheat production worldwide.Rapid detection and quantification of cyst nematodes are essential for more effective control against this nematode disease.In the pres... Heterodera filipjevi continues to be a major threat to wheat production worldwide.Rapid detection and quantification of cyst nematodes are essential for more effective control against this nematode disease.In the present study,a TaqManminor groove binder(TaqMan-MGB)probe-based fluorescence quantitative real-time PCR(qPCR)was successfully developed and used for quantifying H.filipjevi from DNA extracts of soil.The primers and probe designed from the obtained RAPD-SCAR marker fragments of H.filipjevi showed high specificity to H.filipjevi using DNA from isolatesconfirmed species of 23 Heterodera spp.,1 Globodera spp.and 3 Pratylenchus spp.The qPCR assay is highly sensitive and provides improved H.filipjevi detection sensitivity of as low as 4^(-3) single second-stage juvenile(J2)DNAs,10^(-3) female DNAs,and 0.01μgμL^(-1) genomic DNAs.A standard curve relating to the threshold cycle and log values of nematode numbers was generated and validated from artificially infested soils and was used to quantify H.filipjevi in naturally infested field soils.There was a high correlation between the H.filipjevi numbers estimated from 32 naturally infested field soils by both conventional methods and the numbers quantified using the qPCR assay.qPCR potentially provides a useful platform for the efficient detection and quantification of H.filipjevi directly from field soils and to quantify this species directly from DNA extracts of field soils. 展开更多
关键词 cereal cyst nematode Heterodera filipjevi molecular diagnosis quantification TaqMan real-time PCR
下载PDF
Uncertainty quantification of predicting stable structures for high-entropy alloys using Bayesian neural networks
10
作者 Yonghui Zhou Bo Yang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第6期118-124,I0005,共8页
High entropy alloys(HEAs)have excellent application prospects in catalysis because of their rich components and configuration space.In this work,we develop a Bayesian neural network(BNN)based on energies calculated wi... High entropy alloys(HEAs)have excellent application prospects in catalysis because of their rich components and configuration space.In this work,we develop a Bayesian neural network(BNN)based on energies calculated with density functional theory to search the configuration space of the CoNiRhRu HEA system.The BNN model was developed by considering six independent features of Co-Ni,Co-Rh,CoRu,Ni-Rh,Ni-Ru,and Rh-Ru in different shells and energies of structures as the labels.The root mean squared error of the energy predicted by BNN is 1.37 me V/atom.Moreover,the influence of feature periodicity on the energy of HEA in theoretical calculations is discussed.We found that when the neural network is optimized to a certain extent,only using the accuracy indicator of root mean square error to evaluate model performance is no longer accurate in some scenarios.More importantly,we reveal the importance of uncertainty quantification for neural networks to predict new structures of HEAs with proper confidence based on BNN. 展开更多
关键词 Uncertainty quantification High-entropy alloys Bayesian neural networks Energy prediction Structure screening
下载PDF
Host cell protein quantification workflow using optimized standards combined with data-independent acquisition mass spectrometry
11
作者 Steve Hessmann Cyrille Chery +2 位作者 Anne-Sophie Sikora Annick Gervais Christine Carapito 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2023年第5期494-502,共9页
Monitoring of host cell proteins(HCPs)during the manufacturing of monoclonal antibodies(mAb)has become a critical requirement to provide effective and safe drug products.Enzyme-linked immunosorbent assays are still th... Monitoring of host cell proteins(HCPs)during the manufacturing of monoclonal antibodies(mAb)has become a critical requirement to provide effective and safe drug products.Enzyme-linked immunosorbent assays are still the gold standard methods for the quantification of protein impurities.However,this technique has several limitations and does,among others,not enable the precise identification of proteins.In this context,mass spectrometry(MS)became an alternative and orthogonal method that delivers qualitative and quantitative information on all identified HCPs.However,in order to be routinely implemented in biopharmaceutical companies,liquid chromatography-MS based methods still need to be standardized to provide highest sensitivity and robust and accurate quantification.Here,we present a promising MS-based analytical workflow coupling the use of an innovative quantification standard,the HCP Profiler solution,with a spectral library-based data-independent acquisition(DIA)method and strict data validation criteria.The performances of the HCP Profiler solution were compared to more conventional standard protein spikes and the DIA approach was benchmarked against a classical datadependent acquisition on a series of samples produced at various stages of the manufacturing process.While we also explored spectral library-free DIA interpretation,the spectral library-based approach still showed highest accuracy and reproducibility(coefficients of variation<10%)with a sensitivity down to the sub-ng/mg mAb level.Thus,this workflow is today mature to be used as a robust and straightforward method to support mAb manufacturing process developments and drug products quality control. 展开更多
关键词 Host cell proteins Absolute quantification standards Data-independent acquisition
下载PDF
Detection and quantification of Pb and Cr in oysters using laser-induced breakdown spectroscopy
12
作者 闫清霞 田野 +7 位作者 李颖 林洪 贾自文 卢渊 俞进 孙琛 白雪石 Vincent DETALLE 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第4期195-203,共9页
The quantitative determination of heavy metals in aquatic products is of great importance for food security issues.Laser-induced breakdown spectroscopy(LIBS)has been used in a variety of foodstuff analysis,but is stil... The quantitative determination of heavy metals in aquatic products is of great importance for food security issues.Laser-induced breakdown spectroscopy(LIBS)has been used in a variety of foodstuff analysis,but is still limited by its low sensitivity when targeting trace heavy metals.In this work,we compare three sample enrichment methods,namely drying,carbonization,and ashing,for increasing detection sensitivity by LIBS analysis for Pb and Cr in oyster samples.The results demonstrate that carbonization can remove a significant amount of the contributions of organic elements C,H,N and O;meanwhile,the signals of the metallic elements such as Cu,Pb,Sr,Ca,Cr and Mg are enhanced by3–6 times after carbonization,and further enhanced by 5–9 times after ashing.Such enhancement is not only due to the more concentrated metallic elements in the sample compared to the dried ones,but also the unifying of the matter in carbonized and ashed samples from which higher plasma temperature and electron density are observed.This condition favors the detection of trace elements.According to the calibration curves with univariate and multivariate analysis,the ashing method is considered to be the best choice.The limits of detection of the ashing method are 0.52 mg kg-1 for Pb and0.08 mg kg-1 for Cr,which can detect the presence of heavy metals in the oysters exceeding the maximum limits of Pb and Cr required by the Chinese national standard.This method provides a promising application for the heavy metal contamination monitoring in the aquatic product industry. 展开更多
关键词 laser-induced breakdown spectroscopy(LIBS) heavy metal detection signal enhancement sample preparation method quantification OYSTERS
下载PDF
Two-point Dixon and six-point Dixon magnetic resonance techniques in the detection,quantification and grading of hepatic steatosis
13
作者 Mohamed Elfaal Alanna Supersad +6 位作者 Craig Ferguson Stephanie Locas Florin Manolea Mitchell P Wilson Medica Sam Wendy Tu Gavin Low 《World Journal of Radiology》 2023年第10期293-303,共11页
BACKGROUND Hepatic steatosis is a very common problem worldwide.AIM To assess the performance of two-and six-point Dixon magnetic resonance(MR)techniques in the detection,quantification and grading of hepatic steatosi... BACKGROUND Hepatic steatosis is a very common problem worldwide.AIM To assess the performance of two-and six-point Dixon magnetic resonance(MR)techniques in the detection,quantification and grading of hepatic steatosis.METHODS A single-center retrospective study was performed in 62 patients with suspected parenchymal liver disease.MR sequences included two-point Dixon,six-point Dixon,MR spectroscopy(MRS)and MR elastography.Fat fraction(FF)estimates on the Dixon techniques were compared to the MRS-proton density FF(PDFF).Statistical tests used included Pearson’s correlation and receiver operating characteristic.RESULTS FF estimates on the Dixon techniques showed excellent correlation(≥0.95)with MRS-PDFF,and excellent accuracy[area under the receiver operating characteristic(AUROC)≥0.95]in:(1)Detecting steatosis;and(2)Grading severe steatosis,(P<0.001).In iron overload,two-point Dixon was not evaluable due to confounding T2*effects.FF estimates on six-point Dixon vs MRS-PDFF showed a moderate correlation(0.82)in iron overload vs an excellent correlation(0.97)without iron overload,(P<0.03).The accuracy of six-point Dixon in grading mild steatosis improved(AUROC:0.59 to 0.99)when iron overload cases were excluded.The excellent correlation(>0.9)between the Dixon techniques vs MRSPDFF did not change in the presence of liver fibrosis(P<0.01).CONCLUSION Dixon techniques performed satisfactorily for the evaluation of hepatic steatosis but with exceptions. 展开更多
关键词 Chemical shift encoded Dixon magnetic resonance techniques Hepatic steatosis Liver fat quantification Magnetic resonance spectroscopy Proton density fat fraction ULTRASOUND
下载PDF
Hepatic MR imaging using IDEAL-IQ sequence:Will Gd-EOB-DTPA interfere with reproductivity of fat fraction quantification?
14
作者 Yuan Tian Peng-Fei Liu +2 位作者 Jia-Yu Li Ya-Nan Li Peng Sun 《World Journal of Clinical Cases》 SCIE 2023年第25期5887-5896,共10页
BACKGROUND Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence(IDEAL-IQ)is based on chemical shift-based water and fat separation technique to get proton d... BACKGROUND Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence(IDEAL-IQ)is based on chemical shift-based water and fat separation technique to get proton density fat fraction.Multiple studies have shown that using IDEAL-IQ to test the stability and repeatability of liver fat is acceptable and has high accuracy.AIM To explore whether Gadoxetate Disodium(Gd-EOB-DTPA)interferes with the measurement of the hepatic fat content quantified with the IDEAL-IQ and to evaluate the robustness of this technique.METHODS IDEAL-IQ was used to quantify the liver fat content at 3.0T in 65 patients injected with Gd-EOB-DTPA contrast.After injection,IDEAL-IQ was estimated four times,and the fat fraction(FF)and R2* were measured at the following time points:Precontrast,between the portal phase(70 s)and the late phase(180 s),the delayed phase(5 min)and the hepatobiliary phase(20 min).One-way repeated-measures analysis was conducted to evaluate the difference in the FFs between the four time points.Bland-Altman plots were adopted to assess the FF changes before and after injection of the contrast agent.P<0.05 was considered statistically significant.RESULTS The assessment of the FF at the four time points in the liver,spleen and spine showed no significant differences,and the measurements of hepatic FF yielded good consistency between T1 and T2[95%confidence interval:-0.6768%,0.6658%],T1 and T3(-0.3900%,0.3178%),and T1 and T4(-0.3750%,0.2825%).R2* of the liver,spleen and spine increased significantly after injection(P<0.0001).CONCLUSION Using the IDEAL-IQ sequence to measure the FF,we can obtain results that will not be affected by Gd-EOB-DTPA.The high reproducibility of the IDEAL-IQ sequence makes it available in the scanning interval to save time during multiphase examinations. 展开更多
关键词 Gadoxetate Disodium Iterative decomposition of water and fat with echo asymmetry and least squares estimation quantification sequence Fat fraction Enhanced-Magnetic resonance imaging R2*
下载PDF
运用Real-time quantification PCR方法建立副溶血性弧菌在即食虾中的生长预测模型 被引量:5
15
作者 彭织云 王敬敬 +2 位作者 唐晓阳 潘迎捷 赵勇 《食品工业科技》 CAS CSCD 北大核心 2013年第8期108-110,共3页
运用Real-time quantification PCR(real-time qPCR)方法建立副溶血性弧菌在即食虾中生长预测模型。首先构建质粒标准品,梯度稀释后建立标准曲线,然后用Real-time qPCR方法检测虾中副溶血性弧菌的数量,最后建立37℃下即食虾中副溶血性... 运用Real-time quantification PCR(real-time qPCR)方法建立副溶血性弧菌在即食虾中生长预测模型。首先构建质粒标准品,梯度稀释后建立标准曲线,然后用Real-time qPCR方法检测虾中副溶血性弧菌的数量,最后建立37℃下即食虾中副溶血性弧菌生长预测模型,并与传统涂布计数方法进行比较。结果表明,Real-time qPCR方法和传统计数方法均可建立Gmopertz模型、Logistic模型和Richards模型,模型拟合的相关系数R2均在0.9以上。基于Real-timeqPCR方法省时省力、特异性好等优点,用Real-time qPCR方法建立微生物预测模型是未来预测微生物学领域的一种发展趋势。 展开更多
关键词 REAL-TIME quantification PCR 副溶血性弧菌 生长预测模型
下载PDF
Real-Time PCR Technique and Its Application in Quantification of Plant Nucleic Acid Molecules 被引量:8
16
作者 刘进元 《Acta Botanica Sinica》 CSCD 2003年第6期631-637,共7页
Real-time PCR is a closed DNA amplification system that skillfully integrates biochemical, photoelectric and computer techniques. Fluorescence data acquired once per cycle provides rapid absolute quantification of ini... Real-time PCR is a closed DNA amplification system that skillfully integrates biochemical, photoelectric and computer techniques. Fluorescence data acquired once per cycle provides rapid absolute quantification of initial template copy numbers as PCR products are generated. This technique significantly simplifies and accelerates the process of producing reproducible quantification of nucleic acid molecules. It not only is a sensitive, accurate and rapid quantitative method, but it also provides an easier way to calculate the absolute starting copy number of nucleic acid molecules to be tested. Together with molecular bio-techniques, like microarray, real-time PCR will play a very important role in many aspects of molecular life science such as functional gene analysis and disease molecular diagnostics. This review introduces the detailed principles and application of the real-time PCR technique, describes a recently developed system for exact quantification of AUX/IAA genes In Arabidopsis, and discusses the problems with the real-time PCR process. 展开更多
关键词 real-time PCR technique quantification of plant nucleic acid molecules gene expression molecular medicine
下载PDF
规划设计学中的调查分析法14—数量化Ⅰ类(Quantification Theory Type Ⅰ) 被引量:1
17
作者 章俊华 《中国园林》 2003年第9期47-50,共4页
回归及重回归分析和预测,被广泛地应用于各个行业中。但是,有些相当于回归分析中的说明变数,不是数量数据,而是非数量数据,例如:影响入园人数的因素有星期(平日、休日)、天气状况(晴天、阴天、雨雪天等)、季节(春、夏、秋、冬)等。这些... 回归及重回归分析和预测,被广泛地应用于各个行业中。但是,有些相当于回归分析中的说明变数,不是数量数据,而是非数量数据,例如:影响入园人数的因素有星期(平日、休日)、天气状况(晴天、阴天、雨雪天等)、季节(春、夏、秋、冬)等。这些因素因为不是“量”的数据,所以不能用回归或重回归等方法进行分析和预测,但这种情况在规划设计的调查中经常出现,所以数量化Ⅰ类,可以帮助人们进行与回归分析和预测相同的分析,这是十分有效的一种分析方法。 展开更多
关键词 风景园林 规划设计学 调查 数量化I类
下载PDF
Precore/basal core promoter mutants quantification throughout phases of hepatitis B virus infection by Simpleprobe 被引量:8
18
作者 Wen-Hui Tu Ying Lv +8 位作者 Yong-Mei Zhang Wei Hou Jin-Yu Wang Yi-Jun Zhang Hong-Yan Liu Hao-Xiang Zhu Yan-Li Qin Ri-Cheng Mao Ji-Ming Zhang 《World Journal of Gastroenterology》 SCIE CAS 2015年第21期6639-6648,共10页
AIM:To investigate precore/basal core promoter(PC/BCP) mutants throughout hepatitis B virus(HBV) infection and to determine their relationship to hepatitis B early antigen(HBeA g) titers.METHODS:We enrolled 191 patien... AIM:To investigate precore/basal core promoter(PC/BCP) mutants throughout hepatitis B virus(HBV) infection and to determine their relationship to hepatitis B early antigen(HBeA g) titers.METHODS:We enrolled 191 patients in various stages of HBV infection at the Huashan Hospital and the Taizhou Municipal Hospital from 2010 to 2012.None of the patients received antiviral therapy.HBV DNA from serum,was quantified by real-time PCR.The HBV genotype was determined by direct sequencing of the S gene.We used the Simpleprobe ultrasensitivequantitative method to detect PC/BCP mutants in each patient.We compared the strain number,percentage,and the changes in PC/BCP mutants in different phases,and analyzed the relationship between PC/BCP mutants and HBe Ag by multiple linear regression and logistic regression.RESULTS:Patients with HBV infection(n = 191) were assigned to groups by phase:Immune tolerance(IT) = 55,Immune clearance(IC) = 67,Low-replicative(LR) = 49,and HBeA g-negative hepatitis(ENH) = 20.Of the patients(male,112; female,79) enrolled,122 were HBe Ag-positive and 69 were HBe Ag-negative.The median age was 33 years(range:18-78 years).PC and BCP mutation detection rates were 84.82%(162/191) and 96.86%(185/191),respectively.In five HBe Ag-negative cases,we detected double mutation G1896A/G1899 A.The logarithm value of PC mutant quantities(log10 PC) significantly differed in IT,IC,and LR phases,as well as in the ENH phase(F = 49.350,P < 0.001).The logarithm value of BCP mutant quantities(log10 BCP) also differed during the four phases(F = 25.530,P < 0.001).Log10 PC and log10 BCP values were high in the IT and IC phases,decreased in the LR phase,and increased in the ENH phase,although the absolute value at this point remained lower than that in the IT and IC phases.PC mutant quantity per total viral load(PC%) and BCP mutant quantity per total viral load(BCP%) differed between phases(F = 20.040,P < 0.001; F = 10.830,P < 0.001),with PC% and BCP% gradually increasing in successive phases.HBeA g titers negatively correlated with PC%(Spearman's rho =-0.354,P < 0.001) and BCP%(Spearman's rho =-0.395,P < 0.001).The negative correlation between PC% and HBeA g status was significant(B =-5.281,P = 0.001),but there was no such correlation between BCP% and HBeA g status(B =-0.523,P = 0.552).CONCLUSION:PC/BCP mutants become predominant in a dynamic and continuous process.Log10 PC,log10 BCP,PC% and BCP% might be combined to evaluate disease progression.PC% determines HBeA g status. 展开更多
关键词 PRECORE mutant BASAL core promotermutant HEPATITIS B virus quantification HEPATITIS Bearly ANTIGEN titers
下载PDF
Quantificational indexes for design and evaluation of copper staves for blast furnaces 被引量:6
19
作者 Liang Qian Susen Cheng Hongbo Zhao 《Journal of University of Science and Technology Beijing》 CSCD 2008年第1期10-16,共7页
The quantificational and normative design is the precondition of improving the design of copper staves for blast furnaces. Based on a 3-dimensional temperature field calculation model, from the view point of heat tran... The quantificational and normative design is the precondition of improving the design of copper staves for blast furnaces. Based on a 3-dimensional temperature field calculation model, from the view point of heat transfer and long campaigns note with the core of forming accretion, the forming-accretion-ability (FAA) and the rib hot surface maximum temperature difference (ATmax) as quantificational indexes to direct and evaluate the design of copper staves for blast furnaces were presented. The application of the two indexes in design essentially embodies the new long campaigns in the stage of design. With the application of the two indexes, good results can be obtained. Firstly, it was suggested that the rib height of a copper stave can be reduced to 15 mm, which is a new method and theory for the reduction of copper staves. Secondly, the influence of insert on FAA and ATmax, is decided by the volume of insert. According to this, the principle of design for the hot surface geometry of copper staves was put forward that the ratio of the rib hot surface to the copper stave hot surface (abbreviated as the ratio of rib to stave) must be maintained in the range of 45% to 55%; for the present copper stave with a 35-40 mm thick rib, the ratio of rib to stave in the range of 50% to 55% can optimize the design of copper staves; for the copper stave with a smaller rib thickness, for example 15 ram, the ratio of rib to stave in the range of 45% to 50% can optimize the design of copper staves. It can be summarized that the thicker the rib thickness, the larger is the ratio of rib to stave. 2008 University of Science and Technology Beijing. All rights reserved. 展开更多
关键词 blast furnace (BF) copper stave quantificational index forming-accretion-ability
下载PDF
Value of elastography point quantification in improving the diagnostic accuracy of early diabetic kidney disease 被引量:5
20
作者 Qiu-Yun Liu Qi Duan +3 位作者 Xiao-Hong Fu Li-Qian Fu Hong-Wei Xia Yong-Lin Wan 《World Journal of Clinical Cases》 SCIE 2019年第23期3945-3956,共12页
BACKGROUND Diabetic kidney disease(DKD)is a common complication of diabetes.The patient’s prognosis is poor once DKD progresses to advanced stage.Accurate diagnosis and timely treatment of early DKD are important for... BACKGROUND Diabetic kidney disease(DKD)is a common complication of diabetes.The patient’s prognosis is poor once DKD progresses to advanced stage.Accurate diagnosis and timely treatment of early DKD are important for improving patient’s prognosis and reducing mortality.AIM To explore the value of elastography point quantification(ElastPQ)in improving the accuracy of early DKD diagnosis.METHODS A total of 69 patients with type 2 diabetes were recruited from Naval Military Medical University Affiliated Gongli Hospital.Patients were divided into early DKD group and medium DKD group according to pathological results and urinary albumin excretion rate(UAER).Another 40 patients with simple diabetes were included as the diabetes group.The baseline data,laboratory diagnostic indicators,and ultrasound indicators for each patient were recorded.The differences of the indicators in the three groups were compared.Multivariate logistic regression was used to analyze the influencing factors of the development from simple diabetes into early DKD and from early DKD into medium DKD.Receiver operating characteristic analyses of potential indicators in identifying early DKD and medium DKD,and early DKD and simple diabetes were established.RESULTS Multivariate logistic regression analysis showed that UAER(P<0.001),renocortical Young's Modulus(YM)(P<0.001),and renal parenchymal thickness(P=0.013)were the independent influencing factors of the development from early DKD into medium DKD.Diabetes duration(P=0.041),UAER(P=0.034),and renocortical YM(P=0.017)were the independent influencing factors of the development from simple diabetes into early DKD.Receiver operating characteristic analysis indicated that UAER,renocortical YM,and renal parenchymal thickness were accurate in identifying early DKD and medium DKD[all area under curve(AUC)>0.9].The accuracy of UAER(AUC=0.744),diabetes duration(AUC=0.757),and renocortical YM(AUC=0.782)for the diagnosis of early DKD and simple diabetes were limited.However,the combined diagnosis of UAER,diabetes duration,and renocortical YM was accurate in identifying early DKD and simple diabetes(AUC=0.906),which was significantly higher than any of the three indicators(all P<0.05).CONCLUSION ElastPQ is of great value in the diagnosis of early DKD.When combined with the diabetes duration and UAER,it is expected to diagnose accurately early DKD. 展开更多
关键词 DIABETIC kidney disease ELASTOGRAPHY POINT quantification Young's Modulus URINARY ALBUMIN EXCRETION rate Combined diagnosis Diabetes
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部