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A Second Order Accurate in Time, Energy Stable Finite Element Scheme for the Flory-Huggins-Cahn-Hilliard Equation

Advances in Applied mathematics and mechanics 2022年第6期14卷 1477-1508页

作者： maoqin Yuan Wenbin Chen Cheng Wang steven m.Wise Zhengru Zhang School of Science&Arts China University of Petroleum-Beijing at KaramayKaramayXinjiang 834000China Shanghai Key Laboratory of mathematics for Nonlinear Sciences School of Mathematical SciencesFudan UniversityShanghai 200433China Department of mathematics The University of MassachusettsNorth DartmouthMA 02747USA Department of mathematics The University of TennesseeKnoxvilleTN 37996USA School of mathematical Sciences Beijing Normal University and Laboratory of Mathematics and Complex SystemsMinistry of EducationBeijing 100875China

In this paper, we propose and analyze a second order accurate in time, masslumped mixed finite element scheme for the Cahn-Hilliard equation with a logarithmic Flory-Huggins energy potential. The standard backward differentiation formula (BDF)stencil is applied in the temporal discretization. In the chemical potential approximation,both the logarithmic singular terms and the surface diffusion term are treatedimplicitly, while the expansive term is explicitly updated via a second-order Adams-Bashforth extrapolation formula, following the idea of the convex-concave decompositionof the energy functional. In addition, an artificial Douglas-Dupont regularizationterm is added to ensure the energy dissipativity. In the spatial discretization, the masslumped finite element method is adopted. We provide a theoretical justification of theunique solvability of the mass lumped finite element scheme, using a piecewise linearelement. In particular, the positivity is always preserved for the logarithmic argumentsin the sense that the phase variable is always located between -1 and 1. In fact, thesingular nature of the implicit terms and the mass lumped approach play an essentialrole in the positivity preservation in the discrete setting. Subsequently, an unconditionalenergy stability is proven for the proposed numerical scheme. In addition, theconvergence analysis and error estimate of the numerical scheme are also *** numerical experiments are carried out to verify the theoretical properties.

关键词： Cahn-Hilliard equations Flory Huggins energy potential mass lumped FEm convexconcave decomposition energy stability positivity preserving.

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A modified Crank-Nicolson Numerical Scheme for the Flory-Huggins Cahn-Hilliard model

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Communications in Computational Physics 2022年第1期31卷 60-93页

作者： Wenbin Chen Jianyu Jing Cheng Wang Xiaoming Wang steven m.Wise Shanghai Key Laboratory for Contemporary Applied mathematics Fudan UniversityShanghai 200433P.R.China School of mathematical Sciences Fudan UniversityShanghai 200433P.R.China mathematics Department University of MassachusettsNorth DartmouthMA 02747USA International Center for mathematics and Department of mathematics and Guangdong Provincial Key Laboratory of Computational Science and Material Designand National Center for Applied Mathematics ShenzhenSouthern University of Science and TechnologyShenzhen 518055P.R.China mathematics Department University of TennesseeKnoxvilleTN 37996USA

In this paper we propose and analyze a second order accurate numericalscheme for the Cahn-Hilliard equation with logarithmic Flory Huggins energy potential. A modified Crank-Nicolson approximation is applied to the logarithmic nonlinear term, while the expansive term is updated by an explicit second order AdamsBashforth extrapolation, and an alternate temporal stencil is used for the surface diffusion term. A nonlinear artificial regularization term is added in the numerical scheme,which ensures the positivity-preserving property, i.e., the numerical value of the phasevariable is always between -1 and 1 at a point-wise level. Furthermore, an unconditional energy stability of the numerical scheme is derived, leveraging the special formof the logarithmic approximation term. In addition, an optimal rate convergence estimate is provided for the proposed numerical scheme, with the help of linearizedstability analysis. A few numerical results, including both the constant-mobility andsolution-dependent mobility flows, are presented to validate the robustness of the proposed numerical scheme.

关键词： Cahn-Hilliard equation Flory Huggins energy potential positivity preserving energy stability second order accuracy optimal rate convergence estimate

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Achieving Better Educational Practices Through Research Evidence:A Critical Analysis and Case Illustration of Benefits and Challenges

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ECNU Review of Education 2021年第1期4卷 108-127页

作者： steven m.Ross Jennifer R.morrison Johns Hopkins University

Purpose:We examine considerations regarding the positive contributions of evidence accountability and challenges that frustrate educators in gaining access to the needed product ***/Approach/methods:We review the research literature on the multiple characteristics of evidence relative to consumer(practitioner)*** then examine,through a"case illustration"of an initiative in a large school district,a second challenge for evidence usage-conducting viable studies and interpreting outcomes from comprehensive interventions in complex educational ***:Despite attention being given to rigorous evidence,consumers report preferring peer recommendations and local pilot studies as *** our case illustration,we found that the availability of evidence from comprehensive formative evaluation studies was viewed by stakeholders as positively contributing to program implementation quality and sustainability over ***/Value:We use a real-world"case illustration"of a complex initiative in a large,diverse school district to illustrate how current policies and expectations regarding evidence support for educational programs is filtered through multiple agendas and personal needs of key ***,evaluators acquire nontraditional roles that go beyond routine execution of rigorous *** these factors,we offer recommendations for fostering more meaningful and objective interpretations and usage of evidence by local stakeholders.

关键词： Evidence of effectiveness program evaluation technology integration

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Loss of Hox5 function results in myofibroblast mislocalization and distal lung matrix defects during postnatal development

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Science China(Life Sciences) 2018年第9期61卷 1030-1038页

作者： steven m.Hrycaj Leilani marty-Santos ANDrew J.Rasky Nicholas W.Lukacs Deneen m.Wellik Department of Internal medicine Division of Molecular Medicine and Genetics University of Michigan Department of Pathology University of Michigan Department of Cell and Developmental Biology University of Michigan

Alveologenesis is the final stage of lung development and is responsible for the formation of the principle gas exchange units called alveoli. The lung mesenchyme, in particular the alveolar myofibroblasts, are drivers of alveolar development, however,few key regulators that govern the proper distribution and behavior of these cells in the distal lung during alveologenesis have been identified. While Hox5 triple mutants(Hox5 aabbcc) exhibit neonatal lethality, four-allele, compound mutant mice(Hox5 AabbCc) are born in mendelian ratios and are phenotypically normal at birth. However, they exhibit defects in alveologenesis characterized by a BPD-like phenotype by early postnatal stages that becomes more pronounced at adult stages. Invasive pulmonary functional analyses demonstrate significant increases in total lung volume and compliance and a decrease in elastance in Hox5 compound mutants. SmA+ myofibroblasts in the distal lung are distributed abnormally during peak stages of alveologenesis and aggregate, resulting in the formation of a disrupted elastin network. Examination of other key components of the distal lung ECm, as well as other epithelial cells and lipofibroblasts reveal no differences in distribution. Collectively, these data indicate that Hox5 genes play a critical role in alveolar development by governing the proper cellular behavior of myofibroblasts during alveologenesis.

关键词： Hox5 alveologenesis alveolar myofibroblasts lung ECm postnatal lung development

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AAV6 as an effective gene delivery vector for prolonged transgene expression in intervertebral disc cells in vivo

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Genes & Diseases 2022年第4期9卷 1074-1085页

作者： Chi Heon Kim Colleen Oliver Hamid Dar Hicham Drissi steven m.Presciutti Department of Orthopaedics Emory University School of MedicineAtlantaGA 30329USA Atlanta Veteran Affairs medical Center DecaturGA 30030USA

Intervertebral disc degeneration is the main contributor to low back pain,now the leading cause of disability *** transfer,either in a therapeutic attempt or in basic research to understand the mechanisms of disc degeneration,is a fascinating and promising tool to manipulate the complex physiology of the *** vectors based on the adeno-associated virus(AAV)have emerged as powerful transgene delivery vehicles yet a systematic investigation into their respective tropism,transduction efficiency,and relative toxicity have not yet been performed in the disc in ***,we used in vivo bioluminescence imaging to systematically compare multiple AAV serotypes,injection volumes,titers,promoters,and luciferase reporters to determine which result in high transduction efficiency of murine nucleus pulposus(NP)cells in *** find that AAV6 using a CAG promoter to drive transgene expression,delivered into the NP of murine caudal discs at a titer of 1011 GC/mL,provides excellent transduction efficiency/kinetics and low toxicity in *** also show,for the first time,that the transduction of NP cells can be significantly boosted in vivo by the use of small cell permeabilization ***,to our knowledge,we are the first to demonstrate the use of optical tissue clearing and three-dimensional lightsheet microscopy in the disc,which was used to visualize fine details of tissue and cell architecture in whole intact discs following AAV6 *** together,these data will contribute to the success of using AAV-mediated gene delivery for basic and translational studies of the IVD.

关键词： Adeno-associated virus Bioluminescence imaging Cell permeabilization peptide Intervertebral disc Lightsheet microscopy Nucleus pulposus transduction Tissue clearing

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Luminescence of Er^(3+) in Oxyfluoride Transparent Glass-Ceramics

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Journal of Rare Earths 2006年第6期24卷 699-705页

作者： Akira Ueda steven H morgan Richard mu Department of Physics Fisk University NashvilleTN 37208 USA

Erbium doped silicate, germanate, and tellurium-germanate oxyfluoride glasses were prepared in a bulk form. Through appropriate heat treatment of the as-prepared glasses, transparent glass-ceramics （TGCs） were obtained with the formation of β-PbF2：Er^3＋ nanocrystals in the glass matrix were confirmed by X-ray ***-defined diffraction peaks were observed in the samples after heat-treatment. The average crystal diameter of these precipitated crystals from full-width at half-maximum （FWHm） of the diffraction peak was estimated to be between 8 and 13 nm. Optical absorption, photoluminescence, and upconversion luminescence were measured on as-prepared glass and glass-ceramics. Luminescence spectra in the TGC samples revealed well-resolved, sharp stark-splitting peaks, which indicates that a majority of Er^3＋ ions has been incorporated into the crystalline phase of the nanocrystals. The intensity of the visible and near infrared luminescence mostly increases in TSG compared to that in the as-prepared glass. In 1.53 μm absorption and emission bands, the maximum absorption peak is blue-shifted from 1531 to 1507 nm, whereas the maximum emission peak is redshifted from 1535 to 1543 nm in TGC, as compared with that in glass. The bandwidth at half-maximum （BWHm） of the emission band is significantly broader in TGC than in glass, which is beneficial to the erbium-doped fiber amplifier （EDFA）. Upconversion luminescence was measured using 800 nm near-infrared light excitation. Drastically increased upconversion 1 was observed from the TGC as compared to that from their corresponding as-prepared glasses. In addition to a strong green emission centered at 545 nm because of ^4S3/2→^4I15/2 transition and a weaker red emission centered at 662 nm because of ^4F9/2→^4I15/2 transition, generally seen from the Er^3＋ doped glasses, two violet emissions centered at 410 nm because of ^2H9/2→^4I15/2 transition and centered at 379 nm because of ^4G11/2→^4I15/2 transition were also o

关键词： luminescence transparent glass-ceramics rare earths

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Estimates of voluntary activation in individuals with anterior cruciate ligament reconstruction:Effects of type of stimulator,number of stimuli,and quantification technique

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Journal of Sport and Health Science 2022年第1期11卷 85-93页

作者： steven A.Garcia Kazandra m.Rodriguez Scott R.Brown Riann m.Palmieri-Smith Chandramouli Krishnan School of Kinesiology University of MichiganAnn ArborMI 48109USA Neuromuscular and Rehabilitation Robotics Laboratory(NeuRRo Lab) Department of Physical Medicine and RehabilitationUniversity of MichiganAnn ArborMI 48108USA Department of Orthopaedic Surgery Michigan MedicineUniversity of MichiganAnn ArborMI 48109USA Robotics Institute University of MichiganAnn ArborMI 48109USA

Background:Accurate quantification of voluntary activation is important for understanding the extent of quadriceps dysfunction in individuals with anterior cruciate ligament reconstruction(ACLR).Voluntary activation has been quantified using both percent activation derived from the interpolated twitch technique and central activation ratio(CAR)derived from the burst superimposition technique,as well as by using different types of electrical stimulators and pulse train ***,it is unclear how these parameters affect voluntary activation estimates in individuals with *** study was performed to fill this important knowledge gap in the anterior cruciate ligament ***:Quadriceps strength and voluntary activation were examined in 18 ACLR participants(12 quadriceps/patellartendon graft,6 hamstring tendon graft;time since ACLR:1.06±0.82 years,mean±SD)at 90°of knee flexion using 2 stimulators(Digitimer and Grass)and pulse train conditions(3-pulse and 10-pulse).Voluntary activation was quantified by calculating both CAR and percent ***:Results indicated that voluntary activation was significantly overestimated by CAR when compared with percent activation(pmates were not affected by pulse train conditions when using percent activation;however,3-pulse stimuli resulted in greater overestimation than 10-pulse stimuli when using CAR(p=0.003).Voluntary activation did not differ between stimulators(p>0.05);however,the Digitimer evoked greater torque at rest than the Grass(pm the interpolated twitch technique provides superior estimates of voluntary activation than CAR derived from burst superimposition and is less affected by pulse train conditions or stimulators in individuals with ACLR.

关键词： Anterior cruciate ligament Central activation Inhibition Knee strength Triplet Twitch interpolation

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Contemporary indications for and outcomes of hepatic resection for neuroendocrine liver metastases

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World Journal of Gastrointestinal Surgery 2020年第4期12卷 159-170页

作者： steven D Scoville Dimitrios Xourafas Aslam m Ejaz Allan Tsung Timothy Pawlik Jordan m Cloyd Department of Surgery Division of Surgical Oncology at The Ohio State UniversityJames Cancer CenterColumbusOH 43210United States The Arthur G James Comprehensive Cancer Center and Solove Research Institute The Ohio State UniversityColumbusOH 43210United States Department of Surgery Harvard Medical SchoolDepartment of SurgeryBrigham and Women's HospitalHarvard Medical SchoolBostonMA 02215United States Department of Surgery The Ohio State UniversityColumbusOH 43210United States Department of Surgery The Ohio State University Wexner Medical CenterColumbusOH 43210United States Department of Surgery Division of Surgical OncologyThe Ohio State University Wexner Medical CenterColumbusOH 43210United States

BACKGROUND Although surgical resection is associated with the best long-term outcomes for neuroendocrine liver metastases(NELm),the current indications for and outcomes of surgery for NELm from a population perspective are not well *** To determine the current indications for and outcomes of liver resection(LR)for NELm using a population-based *** A retrospective review of the 2014-2017 American College of Surgeons National Surgical Quality Improvement Program and targeted hepatectomy databases was performed to identify patients who underwent LR for *** characteristics and 30-d morbidity and mortality were *** Among 669 patients who underwent LR for NELm,the median age was 60(interquartile range:51-67)and 51%were *** the number of metastases resected ranged from 1 to 9,the most common(45%)number of tumors resected was *** majority(68%)of patients had a largest tumor size ofmy(71%)while fewer underwent a right or left hepatectomy or *** majority of operations were open(82%)versus laparoscopic(17%)or robotic(1%).In addition,30%of patients underwent intraoperative ablation while 45%had another concomitant operation including cholecystectomy(28.8%),bowel resection(20.2%),or partial pancreatectomy(3.4%).Overall 30-d morbidity and mortality was 29%and 1.3%,*** multivariate analysis,American Society of Anesthesiologists class≥3[odds ratios(OR),OR=2.089,95%confidence intervals(CI):1.197-3.645],open approach(OR=1.867,95%CI:1.148-3.036),right hepatectomy(OR=1.618,95%CI:1.014-2.582),and prolonged operative time of>230 min(OR=1.731,95%CI:1.168-2.565)were associated with higher 30-d morbidity while intraoperative ablation and concomitant procedures were *** LR for NELm was performed with relatively low postoperative morbidity and *** procedures performed at the time of LR did not increase morbidity.

关键词： Carcinoid Neuroendocrine tumor Primary tumor resection Intraoperative ablation Cholecystectomy Small bowel resection

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Supercritical fluids:Clean solvents for green chemistry

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Chinese Journal of Chemistry 1999年第3期17卷 212-222,201页

作者： POLIAKOFF martyn GEORGE michael W. HOWDLE steven m. BAGRATASHVILI Viktor N. 韩布兴闫海科 LaserChem Scientific Centre for Technological Lasers of the Russian Academy of Sciences Troitzk (Moscow Region) Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China Department of Chemistry The University of Nottingham Nottingham NG7 2RD England

Supercritical fluids are becoming increasingly attractive as environmentally acceptable replacement for organic solvents in chemical reactions and material processing. This paper highlights some of the properties of supercritical fluids, especially supercritical CO2, which offer particular advantages for the handling of polymers, metal complexes and the environmentally more friendly synthesis and manufacture of chemicals. The paper includes same of the researches in University of Nottingham and a number of recent reviews which together provide a comprehensive introduction.

关键词： Green chemistry supercritical fluids chemical reaction water rapid expansion antisolvent

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Intrahepatic pancreatic pseudocyst:A review of the world literature

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World Journal of Hepatology 2016年第35期8卷 1576-1583页

作者： Andrew Demeusy motahar Hosseini Anne m Sill steven C Cunningham Department of Surgery Saint Agnes Hospital

AImTo investigate and summarize the literature regarding the diagnosis and management of intrahepatic pancreatic pseudocysts (IHPP). mETHODSA literature search was performed using Pubmed (mEDLINE) and Google Scholar databases, followed by a manual review of reference lists to ensure that no articles were missed. All articles, case reports, systematic reviews, letters to editors, and abstracts were analyzed and tabulated. Bivariate analyses were performed, with significance accepted at P RESULTSWe found 41 published articles describing 54 cases since the 1970s, with a fairly steady rate of publication. Patients were predominantly male, with a mean age of 49 years. In 42% of published cases, the IHPP was the only reported pseudocyst, but 58% also had concurrent pseudocysts in other extrapancreatic locations. Average IHPP size was 9.5 cm and they occurred most commonly (48%) in the left hemiliver. Nearly every reported case was managed with an intervention, most with a single intervention, but some required up to three interventions. Percutaneous treatment with either simple aspiration or with an indwelling drain were the most common interventions, frequently performed along with stenting of the pancreatic duct. The size of the IHPP correlated significantly with both the duration of treatment (P = 0.006) and with the number of interventions required (P = 0.031). The duration of therapy also correlated with the initial white blood cell (WBC) count (P = 0.048). CONCLUSIONDiagnosis of IHPP is difficult and often missed. Initial size and WBC are predictive of the treatment required. With appropriate intervention, most patients achieve resolution.

关键词： Pseudocyst Intrahepatic Percutaneous Pancreatic Drainage

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