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Taxifolin stability: In silico prediction and in vitro degradation with HpLC-UV/UpLCe ESI-MS monitoring

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Journal of pharmaceutical Analysis 2021年第2期11卷 232-240页

作者： Fernanda Cristina Stenger Moura Carmem Lúciados Santos Machado Favero Reisdorfer paula Angelica Garcia Couto Maurizio Ricci Valdir Cechinel-Filho Tiago J.Bonomini louis p.sandjo Tania Mari Belle Bresolin pharmaceutical Sciences Graduate program School of Health SciencesCourse of PharmacyUniversidade do Vale do ItajaíItajaíSC88302-202Brazil Laboratory of Research and Development of Drugs Pharmaceutical Sciences Graduate ProgramSchool of Health SciencesCourse of PharmacyUniversidade Federal do PampaUruguaianaRS97500-970Brazil Department of pharmaceutical Science Universita degli Studi di PerugiaPerugiaPG06123Italy Chemistry Department Universidade Federal de Santa CatarinaTrindadeFlorian opolisSC88040-900Brazil

Taxifolin has a plethora of therapeutic activities and is currently isolated from the stem bark of the tree Larix gmelinni(Dahurian larch). It is a flavonoid of high commercial interest for its use in supplements or in antioxidant-rich functional foods. However, its poor stability and low bioavailability hinder the use of flavonoid in nutritional or pharmaceutical formulations. In this work, taxifolin isolated from the seeds of Mimusops balata, was evaluated by in silico stability prediction studies and in vitro forced degradation studies(acid and alkaline hydrolysis, oxidation, visible/UV radiation, dry/humid heating) monitored by high performance liquid chromatography with ultraviolet detection(HpLC-UV) and ultrahigh performance liquid chromatography-electrospray ionization-mass spectrometry(UpLC-ESI-MS). The in silico stability prediction studies indicated the most susceptible regions in the molecule to nucleophilic and electrophilic attacks, as well as the sites susceptible to oxidation. The in vitro forced degradation tests were in agreement with the in silico stability prediction, indicating that taxifolin is extremely unstable(class 1) under alkaline hydrolysis. In addition, taxifolin thermal degradation was increased by *** the other hand, with respect to photosensitivity, taxifolin can be classified as class 4(stable).Moreover, the alkaline degradation products were characterized by UpLC-ESI-MS/MS as dimers of taxifolin. These results enabled an understanding of the intrinsic lability of taxifolin, contributing to the development of stability-indicating methods, and of appropriate drug release systems, with the aims of preserving its stability and improving its bioavailability.

关键词： Dihydroquercetin In silico stability prediction Forced degradation

Developing biophilic intermediate spaces for Arctic housing:Optimizing the thermal,visual,and energy performance

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Building Simulation 2024年第6期17卷 857-875页

作者： Tarlan Abazari Andrépotvin louis Gosselin Claude MH Demers GRAp(Groupe de recherche en ambiance physiques) School of ArchitectureLaval UniversityQuébecCanada Department of Mechanical Engineering Faculty of Science and EngineeringLaval UniversityQuébecCanada

Connecting occupants to the outdoor environment and incorporating biophilic design principles are challenging in extreme Arctic climatic *** Arctic housing models do not provide efficient thermal and daylight transitions which are essential for the well-being and cultural needs of their *** address these challenges,this research develops free-running biophilic intermediate spaces,integrated into an existing Arctic housing *** simulation methods are employed to optimize the primary and secondary architectural design variables for 26 case studies of intermediate *** variables include volume,transparency ratio,and *** variables include materials and physical ***,Daylight Factor/Autonomy,and Energy Use are evaluated as performance *** reveal that free-running intermediate spaces with 6 meters depth and a transparency ratio above 50%provide efficient indoor–outdoor transitions regarding thermal,visual,and energy *** architectural configurations contribute to an approximately 5%reduction in energy consumption within the housing unit compared to the *** side windows prevents the risk of overheating during the summer by reducing the average indoor temperature of intermediate spaces by 7°C but increases the overall energy *** a potential alternative to double-glazing,polycarbonate sheets enable efficient thermal performance by increasing the average indoor temperature of intermediate spaces by approximately 15°C during the cold Arctic *** polycarbonate sheets results in a 16.6%reduction in energy consumption compared to using double-glazing material in intermediate space,and a 26%reduction from the *** outcomes contribute to efficient indoor–outdoor connections and energy efficiency in Arctic housing.

关键词： Arctic housing intermediate spaces biophilic design positive thermal transitions daylight availability energy efficiency

Scanning transmission electron microscopy and atom probe tomography analysis of non-stoichiometry long-period-stacking-ordered structures in Mg-Ni-Y/Sm alloys

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Journal of Magnesium and Alloys 2024年第3期12卷 954-965页

作者： Yimeng Chen Manuel Legrée Jean-louis Bobet Alexander Kvit CAMECA Instruments Inc MadisonWI 53711USA ICMCB Universitéde BordeauxPessacCEDEX 33608France NIAC&Materials Science Department University of WisconsinMadisonWI 53706USA

The long-period-stacking-ordered(LpSO)structure affects the mechanical,corrosion and hydrolysis properties of Mg *** current work employs high angle annular dark field-scanning transmission electron microscopy(HAADF-STEM)and atom probe tomography(ApT)to investigate the structural and local chemical information of LpSO phases formed in Mg-Ni-Y/Sm ternary alloys after extended isothermal *** on the alloying elements and their concentrations,Mg-Ni-Y/Sm develops a two-phase LpSO+α-Mg structure in which the LpSO phase contains defects,hybrid LpSO structure,and Mg ***-STEM and ApT indicate non-stoichiometric LpSO with incomplete Ni_(6)(Y/Sm)_(8) *** addition,the ApT quantitatively determines the local composition of LpSO and confirms the presence of Ni within the Mg bonding *** results provide insight into a better understanding of the structure and hydrolysis properties of LpSO-Mg alloys.

关键词： Magnesium alloys Long-range ordering Atom probe tomography(ApT) STEM HAADF Hydrolysis properties.

Nearest Neighbor Sampling of point Sets Using Rays

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Communications on Applied Mathematics and Computation 2024年第2期6卷 1131-1174页

作者： Liangchen Liu louis Ly Colin B.Macdonald Richard Tsai Department of Mathematics The University of Texas at Austin2515 SpeedwayAustinTX 78712USA Oden Institute for Computational Engineering and Sciences The University of Texas at Austin201 E24th StAustinTX 78712USA Department of Mathematics University of British Columbia1984 Mathematics RdVancouverBCV6T1Z2Canada

We propose a new framework for the sampling,compression,and analysis of distributions of point sets and other geometric objects embedded in Euclidean *** approach involves constructing a tensor called the RaySense sketch,which captures nearest neighbors from the underlying geometry of points along a set of *** explore various operations that can be performed on the RaySense sketch,leading to different properties and potential *** information about the data set can be extracted from the sketch,independent of the ray *** integrals on point sets can be efficiently computed using the *** also present several examples illustrating applications of the proposed strategy in practical scenarios.

关键词： point clouds Sampling Classification Registration Deep learning Voronoi cell analysis

Shear behavior and off-fault damage of saw-cut smooth and tension-induced rough joints in granite

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第4期16卷 1216-1230页

作者： Fanzhen Meng Feili Wang louis Ngai Yuen Wong Jie Song Muzi Li Chuanqing Zhang Liming Zhang College of Science Qingdao University of TechnologyQingdao266033China Department of Earth Sciences The University of Hong KongPokfulamHong KongChina State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China Cooperative Innovation Center of Engineering Construction and Safety Shandong peninsula Blue Economic Zone Qingdao266033China

The damage of rock joints or fractures upon shear includes the surface damage occurring at the contact asperities and the damage beneath the shear surface within the host *** latter is commonly known as off-fault damage and has been much less investigated than the surface *** main contribution of this study is to compare the results of direct shear tests conducted on saw-cut planar joints and tension-induced rough granite joints under normal stresses ranging from 1 Mpa to 50 *** shear-induced off-fault damages are quantified and compared with the optical microscope *** results clearly show that the planar joints slip stably under all the normal stresses except under 50 Mpa,where some local fractures and regular stick-slip occur towards the end of the *** post-peak stress drop and stick-slip occur for all the rough *** residual shear strength envelopes for the rough joints and the peak shear strength envelope for the planar joints almost *** root mean square(RMS)of asperity height for the rough joints decreases while it increases for the planar joint after shear,and a larger normal stress usually leads to a more significant decrease or increase in ***,the extent of off-fault damage(or damage zone)increases with normal stress for both planar and rough joints,and it is restricted to a very thin layer with limited micro-cracks beneath the planar joint *** comparison,the thickness of the damage zone for the rough joints is about an order of magnitude larger than that of the planar joints,and the coalesced micro-cracks are generally inclined to the shear direction with acute *** findings obtained in this study contribute to a better understanding on the frictional behavior and damage characteristics of rock joints or fractures with different roughness.

关键词： planar joint Rough joint Shear behavior Off-fault damage Micro-cracks

Simulation and Analysis of the Effects of pressure and Temperature on the Output Voltage of proton Exchange Membrane Fuel Cells

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Journal of power and Energy Engineering 2024年第2期12卷 1-16页

作者： Kashangabuye Bahufite louis School of Automation Wuhan University of Technology Wuhan China

proton exchange membrane fuel cell has advantages of high energy conversion efficiency, high reliability, no pollution, low operating temperature and rapid start-up. It has become an ideal method of hydrogen energy utilization and is also ideally suited to be used as the main source of energy for automobiles. Currently, it constitutes a research hot spot in the field of new energy vehicles. Based on the working mechanism of proton exchange membrane fuel cells and empirical models, a terminal voltage dynamic model, an open circuit voltage model and three voltage loss models are established. Matlab/Simulink software is utilized to simulate the model and perform analyses in response to the impact of operating temperature and pressure on its performance. To enhance the efficiency of the proton exchange membrane fuel cell, the operating temperature should be increased in the medium and low current density zones and the operating pressure should be increased in the high current density zone.

关键词： Hydrogen Energy New Energy Vehicles Empirical Models Voltage Dynamic Model

Temperature Control of proton Exchange Membrane Fuel Cell Based on Linear Active Disturbance Rejection Control

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Journal of power and Energy Engineering 2024年第5期12卷 1-23页

作者： Kashangabuye Bahufite louis School of Automation Wuhan University of Technology Wuhan China

The performance of proton exchange membrane fuel cells is very sensitive to temperature. The electrochemical reaction results directly in temperature variations in the proton exchange membrane fuel cell. Ensuring effective temperature control is crucial to ensure fuel cell reliability and durability. This paper uses active disturbance rejection control in the thermal management system to maintain the operating temperature and the stack inlet and outlet temperature difference at the set value. First, key cooling system modules such as expansion tanks, coolant circulation pumps and radiators based on Simulink were built. Then, physical modeling and simulation of the fuel cell cooling system was carried out. In order to ensure the effectiveness of the control strategy and reduce the parameter tuning workload, an active disturbance rejection control parameter optimization method using an elite genetic algorithm was proposed. When the optimized control strategy responds to input disturbances, the maximum overshoot of the system is only 1.23% and can reach stability again in 30 s, so the fuel cell temperature can be controlled effectively. Simulation results show that the optimized control strategy can effectively control the stack temperature and coolant temperature difference under the influence of stepped charging current without interference or with interference, and has strong robustness and anti-interference capability.

关键词： Active Disturbance Rejection Control Elite Genetic Algorithm Expansion Tanks Coolant Circulation pumps Radiators

Alexa,let's train now!——A systematic review and classification approach to digital and home-based physical training interventions aiming to support healthy cognitive aging

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Journal of Sport and Health Science 2024年第1期13卷 30-46页

作者： Fabian Herold paula Theobald Thomas Gronwald Navin Kaushal Liye Zou Eling D.de Bruin louis Bherer Notger GMüller Research Group Degenerative and Chronic Diseases MovementFaculty of Health Sciences BrandenburgUniversity of PotsdamPotsdam 14476Germany Body-Brain-Mind Laboratory Shenzhen UniversityShenzhen 518060China Institute of Interdisciplinary Exercise Science and Sports Medicine MSH Medical School HamburgHamburg 20457Germany Department of Health Sciences School of Health&Human SciencesIndiana UniversityIndianapolisIN 46202USA Department of Health Sciences and Technology Institute of Human Movement Sciences and SportETH ZurichZurich 8093Switzerland Department of Neurobiology Care Sciencesand SocietyKarolinska InstituteStockholm 17177Sweden Department of Health OST-Eastern Swiss University of Applied SciencesSt.Gallen 9001Switzerland Montreal Heart Institute MontrealQC H1T 1C8Canada Department of Medicine Universite de MontrealMontrealQC H3T 1J4Canada Centre de Recherche de l'Institut Universitaire de Geriatrie de Montreal MontrealQC H3W 1W5Canada

Background:There is mounting evidence that regular physical activity is an important prerequisite for healthy cognitive ***,the finding that almost one-third of the adult population does not reach the recommended level of regular physical activity calls for further public health *** this context,digital and home-based physical training interventions might be a promising alternative to center-based intervention ***,this systematic review aimed to summarize the current state of the literature on the effects of digital and home-based physical training interventions on adult cognitive ***:In this pre-registered systematic review(pROSpERO;ID:CRD42022320031),5 electronic databases(pubMed,Web of Science,psyclnfo,SpORTDiscus,and Cochrane Library)were searched by 2 independent researchers(FH and pT)to identify eligible studies investigating the effects of digital and home-based physical training interventions on cognitive performance in *** systematic literature search yielded 8258 records(extra17 records from other sources),of which 27 controlled trials were considered *** reviewers(FH and pT)independently extracted data and assessed the risk of bias using a modified version of the Tool for the assEssment of Study qualiTy and reporting in EXercise(TESTEX scale).Results:Of the 27 reviewed studies,15 reported positive effects on cognitive and motor-cognitive outcomes(i.e.,performance improvements in measures of executive functions,working memory,and choice stepping reaction test),and a considerable heterogeneity concerning study-related,population-related,and intervention-related characteristics was noticed.A more detailed analysis suggests that,in particular,interventions using online classes and technology-based exercise devices(i.e.,step-based exergames)can improve cognitive performance in healthy older *** one-half of the reviewed studies were rated as having a high risk of bias with respect

关键词： Brain Cognition Digital health Exercise-cognition physical activity

Non-Recursive Base Conversion Using a Deterministic Markov process

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Journal of Applied Mathematics and physics 2024年第6期12卷 2112-2118页

作者： louis M. Houston Department of Innovation and Research The University of Louisiana at Lafayette Lafayette LA USA

We prove that non-recursive base conversion can always be implemented by using a deterministic Markov process. Our paper discusses the pros and cons of recursive and non-recursive methods, in general. And we include a comparison between non-recursion and a deterministic Markov process, proving that the Markov process is twice as efficient.

关键词： Base Conversion Recursion Euclidean Division Geometric Series Markov process