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Diffusion tensor imaging-derived measures of fractional anisotropy across the pyramidal tract are influenced by the cerebral hemisphere but not by gender in young healthy volunteers： a split-plot factorial analysis of variance

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Chinese Medical Journal 2012年第12期125卷 2180-2187页

作者： Ernesto Roldan-Valadez Edgar Rios-Piedra Rafael Favila Sarael Alcauter Camilo Rios Magnetic Resonance Unit Medica Sur Clinical FoundationMexico CityMexico Tecnologico de Monterrey Health Sciences DivisionMexico City CampusMexico GE Healthcare Mexico CityMexico Imagenes Cerebrales Instituto Nacional de Psiquiatria Ramon dela Fuente Ciudad de MexicoMexico Department of Neurochemistry National Institute of Neurologyand NeurosurgeryMexico CityMexico

Background Diffusion tensor imaging （DTI） permits quantitative examination within the pyramidal tract （PT） by measuring fractional anisotropy （FA）. To the best of our knowledge, the inter-variability measures of FA along the PT remain unexplained. A clear understanding of these reference values would help radiologists and neuroscientists to understand normality as well as to detect early pathophysiologic changes of brain diseases. The aim of our study was to calculate the variability of the FA at eleven anatomical landmarks along the PT and the influences of gender and cerebral hemisphere in these measurements in a sample of young, healthy volunteers. Methods A retrospective, cross-sectional study was performed in twenty-three right-handed healthy volunteers who underwent magnetic resonance evaluation of the brain. Mean FA values from eleven anatomical landmarks across the PT （at centrum semiovale, corona radiata, posterior limb of internal capsule （PLIC）, mesencephalon, pons, and medulla oblongata） were evaluated using split-plot factorial analysis of variance （ANOVA）. Results We found a significant interaction effect between anatomical landmark and cerebral hemisphere （F （10, 32）=4.516, P=0.001; Wilks＇ Lambda 0.415, with a large effect size （partial η2=0.585））. The influence of gender and age was non-significant. On average, the midbrain and PLIC FA values were higher than pons and medulla oblongata values; centrum semiovale measurements were higher than those of the corona radiata but lower than PLIC. Conclusions There is a normal variability of FA measurements along PT in healthy individuals, which is influenced by regions of interest location （anatomical landmarks） and cerebral hemisphere. FA measurements should be reported for comparing same-side and same-landmark PT to help avoid comparisons with the contralateral PT; ideally, normative values should exist for a clinically significant age group. A standardized package of selected DTI processing tools would allow DTI processing to be routinely performed in

关键词： anisotropy diffusion tensor imaging magnetic resonance imaging multivariate analysis analysis of variance

ONE-WAY MULTIVARIATE REPEATED MEASUREMENTS analysis of variance MODEL

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Applied Mathematics(A Journal of Chinese Universities) 2004年第4期19卷 435-448页

作者： Abdul-Hussein Saber AL-MOUEL Dept. of Statist. East China Normal Univ. Shanghai 200062China

The one-way multivariate repeated measurements analysis of variance (1-way MRM ANOVA) model for complete data and the sphericity test are studied.

关键词： one-way multivariate repeated measurements analysis of variance likelihood ratio criterion sphericity test asymptotic expansion.

The default mode network is affected in the early stage of simian immunodeficiency virus infection:a longitudinal study

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Neural Regeneration Research 2023年第7期18卷 1542-1547页

作者： Zhen-Chao Tang Jiao-Jiao Liu Xue-Tong Ding Dan Liu Hong-Wei Qiao Xiao-Jie Huang Hui Zhang Jie Tian Hong-Jun Li Beijing Advanced Innovation Center for Big Data-Based Precision Medicine School of Engineering MedicineBeihang UniversityBeijingChina Key Laboratory of Big Data-Based Precision Medicine(Beihang University) Ministry of Industry and Information Technology of the People’s Republic of ChinaBeijingChina Key Laboratory of Molecular Imaging Institute of AutomationChinese Academy of SciencesBeijingChina Beijing Youan Hospital Capital Medical UniversityBeijingChina Renji Hospital Shanghai Jiao Tong University School of MedicineShanghaiChina Institute of Laboratory Animal Sciences Chinese Academy of Medical SciencesBeijingChina

Acquired immune deficiency syndrome infection can lead to cognitive dysfunction represented by changes in the default mode network.Most recent studies have been cross-sectional and thus have not revealed dynamic changes in the default mode network following acquired immune deficiency syndrome infection and antiretroviral therapy.Specifically,when brain imaging data at only one time point are analyzed,determining the duration at which the default mode network is the most effective following antiretroviral therapy after the occurrence of acquired immune deficiency syndrome.However,because infection times and other factors are often uncertain,longitudinal studies cannot be conducted directly in the clinic.Therefore,in this study,we performed a longitudinal study on the dynamic changes in the default mode network over time in a rhesus monkey model of simian immunodeficiency virus infection.We found marked changes in default mode network connectivity in 11 pairs of regions of interest at baseline and 10 days and 4 weeks after virus inoculation.Significant interactions between treatment and time were observed in the default mode network connectivity of regions of interest pairs area 31/V6.R and area 8/frontal eye field(FEF).L,area 8/FEF.L and caudal temporal parietal occipital area(TPOC).R,and area 31/V6.R and TPOC.L.ART administered 4 weeks after infection not only interrupted the progress of simian immunodeficiency virus infection but also preserved brain function to a large extent.These findings suggest that the default mode network is affected in the early stage of simian immunodeficiency virus infection and that it may serve as a potential biomarker for early changes in brain function and an objective indicator for making early clinical intervention decisions.

关键词： acquired immune deficiency syndrome analysis of variance antiretroviral therapy default mode network functional magnetic resonance imaging human immunodeficiency virus longitudinal study rhesus monkeys simian immunodeficiency virus SIV-mac239

Do model choice and sample ratios separately or simultaneously influence soil organic matter prediction?

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International Soil and Water Conservation Research 2022年第3期10卷 470-486页

作者： Kingsley John Yassine Bouslihim Kokei Ikpi Ofem Lahcen Hssaini Rachid Razouk Paul Bassey Okon Isong Abraham Isong Prince Chapman Agyeman Ndiye Michael Kebonye Chengzhi Qin Department of Soil Science and Soil Protection Faculty of AgrobiologyFoodand Natural ResourcesCzech University of Life SciencesKamýcka 12916500PragueCzech Republic National Institute of Agricultural Research Morocco Department of Soil Science Faculty of AgricultureForestry and Wildlife Resources ManagementUniversity of CalabarPMB 1115540004Etta Agbo RoadCalabarNigeria State Key Laboratory of Resources and Environmental Information System Institute of Geographical Sciences and Natural Resources ResearchCASBeijing100101China

This study was performed to examine the separate and simultaneous influence of predictive models’choice alongside sample ratios selection in soil organic matter(SOM).The research was carried out in northern Morocco,characterized by relatively cold weather and diverse geological conditions.The dataset herein used accounted for 1591 soil samples,which were randomly split into the following ratios:10%(∼150 sample ratio),20%(∼250 sample ratio),35%(∼450 sample ratio),50%(∼600 sample ratio)and 95%(∼1200 sample ratio).Models herein involved were ordinary kriging(OK),regression kriging(RK),multiple linear regression(MLR),random forest(RF),quantile regression forest(QRF),Gaussian process regression(GPR)and an ensemble model.The findings in the study showed that the accuracy of SOM prediction is sensitive to both predictive models and sample ratios.OK combined with 95%sample ratio performed equally to RF in conjunction with all the sample ratios,as the latter did not show much sensitivity to sample ratios.ANOVA results revealed that RF with a∼10%sample ratio could also be optimum for predicting SOM in the study area.In conclusion,the findings herein reported could be instrumental for producing cost-effective detailed and accurate spatial estimation of SOM in other sites.Furthermore,they could serve as a baseline study for future research in the region or elsewhere.Therefore,we recommend conducting series of simulation of all possible combinations between various predictive models and sample ratios as a preliminary step in soil organic matter prediction.

关键词： analysis of variance Agriculture Digital soil mapping Predictive mapping Mediterranean

Modeling and analysis of pelletization process based on a multi-hole pelletizing device

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International Journal of Agricultural and Biological Engineering 2019年第1期12卷 17-23页

作者： Qinghai Jiang Kai Wu Yu Sun School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094China

A multi-hole pelletizing device(MPD)was proposed to simulate the granular extrusion process of animal feed due to its cheap,fast,and controllable features.The compression mechanism was analyzed and discussed according to the compression force-time curve.This study applied response surface methodology(RSM)with a central composite design(CCD)to develop predictive models for the compression force Fout and the pellet properties which includes pellet densityρp,pellet moisture content Mcp,and pellet tensile strength Dp based on the MPD.The effects of feedstock moisture content Mcf(10%-18%w.b.),feedstock particle size Sf(8 meshes-24 meshes),die temperature Td(70°C-110°C)and compression speed Vc(5 mm/min to 25 mm/min)were investigated.Response surface models developed for the compression force and pellet properties have adequately described the pelleting process(R^(2)>0.95).The results showed the significant effects of all factors and most of the squared and interaction terms on the compression force and pellet physical properties.It can be concluded from the present study that moisture content and die temperature,followed by compression speed and feedstock particle size are the interacting process factors influencing compression force and pellet properties.

关键词： animal feed pelletization modeling compression force response surface methodology analysis of variance

AN　analysis　OF　AMULTIVARIATE　TWO－WAY　MODEL　WITH　INTERACTION　AND　NO　REPLICATION

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Acta Mathematicae Applicatae Sinica 1994年第4期10卷 387-400页

作者：郭大伟 Department of Mathematics Anhui Normal University Wuhu China

In this paper, we consider the problem of testing the hypothesis of no interaction in the multivariate two-way classification model with one observation per cell. If the error covariance matrix is unknown, we suggest pseudo-maximum likelihood estimation (PMLE) of the parameters and give the invariant test for the hypothesis of no interaction. Further, we develop also some tests for the case of an unknown diagonal positive definite error covariance matrix.

关键词： analysis of variance interaction pseudo-maximum likelihood estimate maximal invariant, invariant test

A novel optimal design for an application-oriented synthetic jet actuator

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Chinese Journal of Aeronautics 2014年第3期27卷 514-520页

作者： Deng Xiong Xia Zhixun Luo Zhenbing Wang Lin Science and Technology on Scramjet Laboratory National University of Defense Technology

The evaluation indicator for the performance of a synthetic jet actuator （SJA） is well-defined because of its various applications, which require optimal design to improve its performance and extend its field of application. This paper presents a novel approach to the optimal design of an SJA applied to enhance fuel/air mixture. It optimizes the combination of an actuator＇s geometric parameters by selecting the strength of vortex pairs as the evaluation indicator, coupled with orthogonal experiments and analysis of variance （AOV）. The results indicate that slot width is the most notable factor influencing the strength of vortex pairs, followed by cavity height and slot depth. The optimal value of the strength of vortex pairs increases by 32.5%over the experimental data of the base case, and more than 8.4%compared with the simulation results of the orthogonal experiments. It is concluded that the optimal method can effectively improve the performance of an SJA applied in mixing enhancement, reducing the test numbers and the associated design cycle and cost.

关键词： analysis of variance Evaluation indicator Orthogonal experiment Strength of vortex pairs Synthetic jet

Wear Studies on Metal Matrix Composites: a Taguchi Approach

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Journal of Materials Science & Technology 2005年第6期21卷 845-850页

作者： S.Basavarajappa G.Chandramohan Department of Mechanical Engineering PSG College of Technology 641 004 Coimbatore India

An attempt has been made to study the influence of wear parameters like applied load, sliding speed, sliding distance and percentage of reinforcement on the dry sliding wear of the metal matrix composites. A plan of experiments, based on techniques of Taguchi, was performed to acquire data in controlled way. An orthogonal array and the analysis of variance were employed to investigate the influence of process parameters on the wear of composites. The objective is to establish a correlation between dry sliding wear of composites and wear parameters. These correlations were obtained by multiple regressions. Finally, confirmation tests were conducted to verify the experimental results foreseen from the mentioned correlations.

关键词： Metal matrix composites Wear Orthogonal array analysis of variance Taguchi method

Systematic Study of Nanocrystalline Plasma Electrolytic Nitrocarburising of 316L Austenitic Stainless Steel for Corrosion Protection

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Journal of Materials Science & Technology 2007年第5期23卷 665-671页

作者： M.Aliofkhazraei P.Taheri A.Sabour Rouhaghdam Ch.Dehghanian Materials Engineering Department Faculty of EngineeringTarbiat Modares UniversityTehranIran Materials Engineering Department Faculty of EngineeringTehran UniversityTehranIran

A number of studies have been reported on the use of nanocrystalline plasma electrolytic nitrocarburising technology for surface hardening of stainless steels for higher corrosion resistance resulted from this technique. However, very few studies have focused on the optimization of the nanocrystalline plasma electrolytic nitrocarburising process parameters. In this study, a design of experiment （DOE） technique, the Taguchi method, has been used to optimize the nanocrystalline plasma electrolytic nitrocarburising not only for surface hardening but also for the corrosion protection of 316L austenitic stainless steel by controlling the coating processes factors. The experimental design consisted of four factors （Urea concentration, electrical conductivity of electrolyte, voltage and duration of process）, each containing three levels. Potentiodynamic polarization measurements were carried out to determine the corrosion resistance of the coated samples. The results were analyzed with related software. An analysis of the mean of signal-to-noise （S/N） ratio indicated that the corrosion resistance of nanocrystalline plasma electrolytic nitrocarburised 316L stainless steel was influenced significantly by the levels in the Taguchi orthogonal array. The optimized coating parameters for corrosion resistance are 1150 g/L for urea concentration, 360 mS/cm for electrical conductivity of electrolyte, 260 V for applied voltage, 6 min for treatment time. The percentage of contribution for each factor was determined by the analysis of variance （ANOVA）. The results showed that the applied voltage is the most significant factor affecting the corrosion resistance of the coatings.

关键词： Nanocrystalline plasma electrolytic nitrocarburising 316L austenitic stainlesssteel Corrosion resistance Potentiodynamic polarization analysis of variance