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A mathematical model of circadian rhythms synchronization using fractional differential equations system of coupled van der Pol oscillators

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International journal of Biomathematics 2018年第1期11卷 313-336页

作者： j. E. Escalante-Martfnez j. F. Gomez-Aguilar C. Calderon-Ramon A. Aguilar-Melendez P. Padilla-Longoria Facultad de Ingenieria Mecdnica y Eldctrica Universidad Veracruzana Av. Venustiano Carranza S/N Col. Revolucidn C. P. 93390 Poza Riea Veracruz Mdxico CONACyT-TecnolSgico Nacional de Mexico/CENIDET Interior Internado Palmira S/N Col. Palmira C. P. 62490 Cuernavaca Morelos Mexico Facultad de Ingenier~a Mecdnica y Eldctrica Universidad Veracruzana Av. Venustiano Carranza S/ZN Col. Revolucidn C. P. 93390 Poza Rica Veracruz Mexico Facul$ad de Ingenierd Civil Universidad Veracruzana Av. Venustiano Carranza S/N Col. Revolucion C. P. 93390 Poza Rica Veracruz Mexico Instituto de Investigaciones en Matemdticas Aplicadas ySistemas (IIMAS) UNAM Circuito Escolar Cd. Universitaria Del. Coyoacan Mdxico D. F. C. P. 04510 Mexico

This paper presents an alternative representation of a system of differential equations qualitatively showing the behavior of the biological rhythm of a crayfish during their transition from juvenile to adult stages. The model focuses on the interaction of four cellular oscillators coupled by diffusion of a hormone, a parameter μ is used to simu- late the quality of communication among the oscillators, in biological terms, it mea- sures developmental maturity of the crayfish. Since some quorum-sensing mechanism is assumed to be responsible for the synchronization of the biological oscillators, it is nat- ural to investigate the possibility that the underlying diffusion process is not standard, i.e. it may be a so-called anomalous diffusion. In this case, it is well understood that diffusion equations with fractional derivatives describe these processes in a more realis- tic way. The alternative formulation of these equations contains fractional operators of Liouville-Caputo and Caputo-Fabrizio type. The numerical simulations of the equations reflect synchronization of ultradian rhythms leading to a circadian rhythm. The classical behavior is recovered when the order of the fractional derivative is V = 1. We discuss possible biological implications.

关键词： Circadian rhythm van der Pol oscillators Liouville-Caputo fractional oper-ator Caput^Fabrizio fractional operator Adams Bashforth Moulton method syn-chronicity.

High-Throughput Phenotyping of Dynamic Canopy Traits Associated with Stay-Green in Grain Sorghum

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Plant Phenomics 2020年第1期2卷 269-278页

作者： j.D.Liedtke C.H.Hunt B.George-jaeggli K.Laws j.Watson A.B.Potgieter A.Cruickshank D.R.jordan University of Hohenheim 70593 StuttgartGermany Agri-Science Queensland Department of Agriculture and FisheriesWarwickQLD 4370Australia Queensland Alliance for Agriculture and Food Innovation The University of QueenslandWarwickQLD 4370Australia Queensland Alliance for Agriculture and Food Innovation The University of QueenslandGatton CampusToowoomba QLD 4343Australia

Drought is a recurring phenomenon that puts crop yields at risk and threatens the livelihoods of many people around the ***-green is a drought adaption phenotype found in sorghum and other *** expressing this phenotype show less drought-induced senescence and maintain functional green leaves for longer when water limitation occurs during grain fill,conferring benefits in both yield per se and *** physiological causes of the phenotype are postulated to be water saving through mechanisms such as reduced canopy size or access to extra water through mechanisms such as deeper *** sorghum breeding programs,stay-green has traditionally been assessed by comparing visual scores of leaf senescence either by identifying final leaf senescence or by estimating rate of leaf *** this study,we compared measurements of canopy dynamics obtained from remote sensing on two sorghum breeding trials to stay-green values(breeding values)obtained from visual leaf senescence ratings in multienvironment breeding trials to determine which components of canopy development were most closely linked to the stay-green ***,canopy size as estimated using preflowering canopy parameters was weakly correlated with stay-green values for leaf senescence while postflowering canopy parameters showed a much stronger association with leaf *** study suggests that factors other than canopy size have an important role in the expression of a stay-green phenotype in grain sorghum and further that the use of UAVs with multispectral sensors provides an excellent way of measuring canopy traits of hundreds of plots grown in large field trials.

关键词： breeding drought hundreds

Numerical　Solution　of　Flow　Field　Diagnosis　Problem　in　Multistage　Axial　Compressors

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journal of Thermal Science 1995年第2期4卷 96-99页

作者： Z.C.Zhang j.Liu 等 DepartmentofThermalEngineering TsinghuaUniversityBeijing100084China DepartmentofThermalEngineering

A mathematical model is developed for the flow field diagnosis problem in multistage axial compressors. In view of the ill-posedness of the diagnostic problem, an effective measure is adopted to transfer the diagnostic problem into a variational problem which is solved by a regularization method. Two numerical results demonstrate the rationality of the flow field diagnosis Problem and the effectiveness of the computational method.

关键词： compressor flow field diagnosis posedness.

Establishment of Withania somnifera Hairy Root Cultures for the Production of Withanolide A

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journal of Integrative Plant Biology 2008年第8期50卷 975-981页

作者： Hosakatte N. Murthy Camelia Dijkstra Paul Anthony Daniel A. White Mike R. Davey j. Brian Power Eun j. Hahn Kee Y. Paek Plant Sciences Division School of Biosciences University of Nottingham Sutton Bonington Campus Loughborough LE12 5RD UK Department of Botany Karnatak University Dharwad 580 003 India Research Center for the Development of Advanced Horticultural Technology Chungbuk National University Cheongju 361-763 Korea Department of Botany Karnatak University Dharwad 580 003 India Food Sciences Division School of Biosciences University of Nottingham Sutton Bonington Campus Loughborough LE12 5RD UK Research Center for the Development of Advanced Horticultural Technology Chungbuk National University Cheongju 361-763 Korea

Withania sominifera （Indian ginseng） was transformed by Agrobacterium rhizogenes. Explants from seedling roots, stems, hypocotyls, cotyledonary nodal segments, cotyledons and young leaves were inoculated with A. rhizogenes strain R1601. Hairy （transformed） roots were induced from cotyledons and leaf explants. The transgenic status of hairy roots was confirmed by polymerase chain reaction using nptll and rolB specific primers and, subsequently, by Southern analysis for the presence of nptll and rolB genes in the genomes of transformed roots. Four clones of hairy roots were established; these differed in their morphology. The doubling time of faster growing cultures was 8-14 d with a fivefold increase in biomass after 28 d compared with cultured, non-transformed seedling roots. MS-based liquid medium was superior for the growth of transformed roots compared with other culture media evaluated （SH, LS and N6）, with MS-based medium supplemented with 40 g/L sucrose being optimal for biomass production. Cultured hairy roots synthesized withanolide A, a steroidal lactone of medicinal and therapeutic value. The concentration of withanolide A in transformed roots （157.4 μg/g dry weight） was 2.7-fold more than in non-transformed cultured roots （57.9 μg/g dry weight）.

关键词： Agrobacterium rhizogenes hairy (transformed) roots Indian ginseng transformation withanolide A

Analysis of inhibition of concrete steel-rebar corrosion by Na_2Cr_2O_7 concentrations:Implications for conflicting reports on inhibitor effectiveness

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journal of Central South University 2013年第12期20卷 3697-3714页

作者： j.O.Okeniyi I.O.Oladele I.j.Ambrose S.O.Okpala O.M.Omoniyi C.A.Loto A.P.I.Popoola Mechanical Engineering Department Covenant University Chemical Metallurgical and Materials Engineering Department Tshwane University of Technology

Corrosion test data were measured using non-destructive electrochemical techniques and analysed for studying inhibition effectiveness by different concentrations of NazCr207 on the corrosion of concrete steel-rehar in NaC1 and in H2SO4 media. For these, specifications of ASTM G16-95 R04 were combined with the normal and the Gumbel probability density functions as model analytical methods for addressing issues of conflicting reports of inhibitor effectiveness that had generated concerns. Results show that reinforced concrete samples admixed with concentrations having 4 g （0.012 7 tool）, 8 g （0.025 4 mol） and 6 g （0.019 l tool） NaaCr207 exhibited, in that order, high inhibition effectiveness, with respective efficiency, r/, of （90.46±1.30）%, （88.41＋2.24）% and （84.87±4.74）%, in the NaC1 medium. These exhibit good agreements within replicates and statistical methods for the samples. Also, optimal inhibition effectiveness model in the H2SO4 medium was exhibited by 8 g （0.025 4 mol） Na2Cr207 concentration having r/=（78.44±1.10）%. These bear implications for addressing conflicting test data in the study of effective inhibitors for mitigating steel-rebar corrosion in aggressive environments.

关键词： corrosion inhibitor effectiveness saline/marine and industrial/microbial environments concrete steel-rebar normal andGumbel probability distribution functions Kolmogorov-Smirnov statistics tests of significance

Contribution to the understanding of the performance differences between commercial current collectors in Li–S batteries

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journal of Energy Chemistry 2021年第11期30卷 295-306,I0007页

作者： A.Benitez F.Luna-Lama ACaballero E.Rodriguez-Castellon j.Morales Dpto.Química Inorgánica e Ingeniería Química Instituto Universitario de Nanoquímica(IUNAN)Universidad de Córdoba14071 CórdobaSpain Dpto.de Química Inorgánica Cristalografía y MineralogíaFacultad de CienciasUniversidad de Málaga29071 MálagaSpain

Lithium–sulfur batteries have been recognised as highly promising next-generation batteries, due to their low cost and high theoretical energy density. Despite numerous advances in this technology over the last decade, its commercialisation is still a challenge that has not yet been achieved. Many efforts have been made to improve the problems that these batteries present, mainly by investigating different cathode manufacturing strategies, testing novel Li anodes, new additives in the electrolytes, and modified separators or interlayers. However, the characteristics of the current collectors used in the preparation of the electrodes have been rarely addressed. Three commercial collectors are commonly used in basic research on Li–S batteries: Al foil, carbon coated Al foil (Al-C), and carbon paper (gas diffusion layer, GDL). In this work, a detailed study of the electrochemical response of these commercial collectors has been carried out. The tests were carried out on two S composites formed by carbons of a different natures, commercial carbon black and synthetic N-doped graphene. In addition, the S impregnation method was different, using either melt diffusion at 155 ℃ or ethylenediamine as S solvent, respectively. In both systems, the results were similar – the electrodes supported on GDL delivered higher specific capacities than those supported on Al and Al-C, with minimal differences between the two. Of the different collector properties examined to explain this behaviour, namely Al corrosion, electrical conductivities, surface-level composition, and surface texture, only the latter had a significant effect in the performance of GDL-based electrodes. SEM images revealed a rough and cracked surface formed by the agglomerated carbon particles that give rise to a complex pore system, predominantly consisting of macropores. All of these features are beneficial for a better anchoring of the active material on the collector surface, in addition to enhancing the wettabi

关键词： Current collector Carbon paper Aluminum foil Lithium–sulfur battery

High yield reproducible rat model recapitulating human Barrett's carcinogenesis

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World journal of Gastroenterology 2017年第33期23卷 6077-6087页

作者： Daisuke Matsui Ashten N Omstead juliann E Kosovec Yoshihiro Komatsu Emily j Lloyd Hailey Raphael Ronan j Kelly Ali H Zaidi Blair A jobe Esophageal and Lung Institute Allegheny Health Network Department of Gastroenterological Surgery Kanazawa University Hospital Department of Oncology Sidney Kimmel Comprehensive Cancer CenterJohns Hopkins Hospital

AIM To efficiently replicate the biology and pathogenesis of human esophageal adenocarcinoma(EAC) using the modified Levrat model of end-to-side esophagojejunostomy. METHODS End-to-side esophagojejunostomy was performed on rats to induce gastroduodenoesophageal reflux to develop EAC. Animals were randomly selected and serially euthanized at 10(n = 6),17(n = 8),24(n = 9),31(n = 6),38(n = 6),and 40(n = 6) wk postoperatively. The esophagi were harvested for downstream histopathology and gene expression. Histological evaluation wascompleted to determine respective rates of carcinogenic development. Quantitative reverse transcriptionpolymerase chain reaction was performed to determine gene expression levels of MUC2,CK19,and CK20,and results were compared to determine significant differences throughout disease progression *** The overall study mortality was 15%. Causes of mortality included anastomotic leak,gastrointestinal hemorrhage,stomach ulcer perforation,respiratory infection secondary to aspiration,and obstruction due to tumor or late anastomotic stricture. 10 wk following surgery,100% of animals presented with esophagitis. Barrett's esophagus(BE) was first observed at 10 wk,and was present in 100% of animals by 17 wk. Dysplasia was confirmed in 87.5% of animals at 17 wk,and increased to 100% by 31 wk. EAC was first observed in 44.4% of animals at 24 wk and increased to 100% by 40 wk. In addition,two animals at 38-40 wk post-surgery had confirmed macro-metastases in the lung/liver and small intestine,respectively. MUC2 gene expression was progressively down-regulated from BE to dysplasia to EAC. Both CK19 and CK20 gene expression significantly increased in a stepwise manner from esophagitis to EAC. CONCLUSION Esophagojejunostomy was successfully replicated in rats with low mortality and a high tumor burden,which may facilitate broader adoption to study EAC development,progression,and therapeutics.

关键词： Esophageal adenocarcinoma gastroeso phageal reflux disease Levrat Esophagojejunostomy Experimental rat model Mucin genes Cytokeratins

Error induced by the estimation of the corneal power and the effective lens position with a rotationally asymmetric refractive multifocal intraocular lens

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International journal of Ophthalmology(English edition) 2015年第3期8卷 501-507页

作者： David P.Piero Vicente j.Camps María L.Ramón Verónica Mateo Rafael j.Pérez-Cambrodí Grupo de óptica y Percepción Visual (GOPV).Department of Optics Pharmacology and Anatomy University of Alicante San Vicente del Raspeig Alicante 03690 Spain Department of Ophthalmology (Oftalmar) Vithas Medimar International Hospital Foundation for the Visual Quality (FUNCAVIS: Fundación para la Calidad Visual) Alicante 03016 Spain

AIM : To evaluate the prediction error in intraocular lens(IOL) power calculation for a rotationally asymmetric refractive multifocal IOL and the impact on this error of the optimization of the keratometric estimation of the corneal power and the prediction of the effective lens position(ELP).METHODS: Retrospective study including a total of 25 eyes of 13 patients(age, 50 to 83y) with previous cataract surgery with implantation of the Lentis Mplus LS-312 IOL(Oculentis Gmb H, Germany). In all cases, an adjusted IOL power(P IOLadj) was calculated based on Gaussian optics using a variable keratometric index value(n kadj) for the estimation of the corneal power(P kadj) and on a new value for ELP(ELP adj) obtained by multiple regression *** P IOLadj was compared with the IOL power implanted(P IOLReal) and the value proposed by three conventional formulas(Haigis, Hoffer Q and Holladay Ⅰ).RESULTS: P IOLReal was not significantly different than P IOLadj and Holladay IOL power(P >0.05). In the Bland and Altman analysis, P IOLadj showed lower mean difference(-0.07 D) and limits of agreement(of 1.47 and-1.61 D)when compared to P IOLReal than the IOL power value obtained with the Holladay formula. Furthermore, ELP adj was significantly lower than ELP calculated with other conventional formulas(P j. CONCLUSION: Refractive outcomes after cataract surgery with implantation of the multifocal IOL Lentis Mplus LS-312 can be optimized by minimizing thekeratometric error and by estimating ELP using a mathematical expression dependent on anatomical factors.

关键词： Mplus multifocalintraocularlens keratometry effective lens position intraocular lens power

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