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Quasi-Static, Poiseuille Flow of Analgesics from an Elastomeric Pump: Theoretical Determination of Infusion Times and Toxicity conditions

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Journal of Biosciences and Medicines 2024年第9期12卷 251-265页

作者： clare B. Lipscombe Trevor c. Lipscombe don S. Lemons Division of General Surgery Vanderbilt University Medical Center Nashville TN USA catholic University of America Press Washington DC USA Department of Physics Bethel College North Newton KS USA

Background: Elastomeric pumps (elastic balls into which analgesics or antibiotics can be inserted) push medicines through a catheter to a nerve or blood vessel. Since elastomeric pumps are small and need no power source, they fit easily into a pocket during infusion, allowing patient mobility. Elastomeric pumps are widely used and widely studied experimentally, but they have well-known problems, such as maintaining reliable flow rates and avoiding toxicity or other peak-and-trough effects. Objectives: Our research objective is to develop a realistic theoretical model of an elastomeric pump, analyze its flow rates, determine its toxicity conditions, and otherwise improve its operation. We believe this is the first such theoretical model of an elastomeric pump consisting of an elastic, medicine-filled ball attached to a horizontal catheter. Method: Our method is to model the system as a quasi-Poiseuille flow driven by the pressure drop generated by the elastic sphere. We construct an engineering model of the pressure exerted by an elastic sphere and match it to a solution of the one-dimensional radial Navier-Stokes equation that describes flow through a horizontal, cylindrical tube. Results: Our results are that the model accurately reproduces flow rates obtained in clinical studies. We also discover that the flow rate has an unavoidable maximum, which we call the “toxicity bump”, when the radius of the sphere approaches its terminal, unstretched value—an effect that has been observed experimentally. conclusions: We conclude that by choosing the properties of an elastomeric pump, the toxicity bump can be restricted to less than 10% of the earlier, relatively constant flow rate. Our model also produces a relation between the length of time that the analgesic fluid infuses and the physical properties of the fluid, of the elastomeric sphere and the tube, and of the blood vessel into which the analgesic infuses. From these, we conclude that elastomeric pumps can be design

关键词： Elastomeric Pump Infusion Therapy Bio-Fluids Medical Devices Antibiotic Delivery Analgesic Delivery

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Endoscopic ultrasound-guided portal pressure gradient identifies patients with previously undiagnosed clinically significant portal hypertension

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Portal Hypertension & cirrhosis 2024年第2期3卷 67-74页

作者： Jerome c.Edelson Scott F.D.Edelson John G.Quiles cyrus V.Edelson Eric M.Montminy christian L.Horn John P.Magulick don c.roc.ey Department of Gastroenterology and Hepatology Brooke Army Medical CenterFort Sam HoustonTexasUSA Department of Medicine Uniformed Services University of the Health SciencesBethesdaMarylandUSA Department of Medicine Brooke Army Medical CenterFort Sam HoustonTexasUSA John H.Stroger Jr.Hospital of cook county ChicagoIllinoisUSA Digestive Disease Research center Medical University of South CarolinaCharlestonSouth CarolinaUSA

Aims:Portal hypertension(PH)is a complication of cirrhosis that leads to hepatic *** the portal pressure gradient(PPG)provides valuable information for disease assessment,staging,and *** this study,we aimed to report the utilization of endoscopic ultrasound(EUS)-guided PPG(EUS-PPG)measurements in a real-world ***:This retrospective analysis included patients at a tertiary care center who underwent EUS-PPG between February 2021 and May *** most common indication was to establish or exclude the diagnosis of cirrhosis,followed by an assessment of surgical risk in the setting of suspected *** demographic and clinical data were collected,and statistical analysis was performed using the Student's t ***:Eighteen patients underwent *** success was achieved in 17 of the 18 *** complications were *** mean scores of child-Pugh,Model for End-Stage Liver Disease-Sodium,and Fibrosis-4 scores were 5.1±0.5,9.0±3.0,and 3.7±4.5,*** the 18 patients,two presented with esophageal varices and six with portal hypertensive *** mean PPG was 5.8±4.5 mmHg,and five patients exhibited clinically significant PH(cSPH).Of the 18 patients,15 underwent concurrent EUS-liver biopsy,which was 100%successful and provided diagnostic histology for all *** PPG data led to changes in the clinical management of 17 ***:EUS-PPG is safe and technically *** child-Pugh score did not correlate well with the presence of cSPH;however,PPG measurements resulted in changes in the management of almost all *** studies correlating EUS-PPG with other assessments of liver diseases are required.

关键词： EUS portal hypertension portal pressure gradient

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Process development for the direct solvent extraction of nickel and cobalt from nitrate solution:aluminum,cobalt,and nickel separation using cyanex 272

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International Journal of Minerals,Metallurgy and Materials 2017年第1期24卷 37-46页

作者： Zela T.Ichlas don c.lbana Leaching and Separation Technologies Group Department of Mining Engineering and Metallurgical EngineeringWA School of MinesCurtin UniversityKalgoorlieWA 6430Australia

A direct solvent extraction（DSX） process for purifying nickel and cobalt from the nitric acid leach solution of nickel laterite ores was conceived and experimentally probed. The proposed process consists of two solvent extraction（SX） steps but with only one extractant - bis（2,4,4-trimethylpentyl）phosphinic acid（cyanex？ 272） - used in both steps. The first extraction step involved the removal of aluminum and zinc, whereas the second extraction step involved the separation of cobalt along with manganese from nickel. The experimental results showed essentially quantitative removal of aluminum（〉97%） and zinc（〉99%） in a single extraction stage using 20vol% cyanex 272 at pH 2.1. Some cobalt（32%） and manganese（55%） were co-extracted but were easily scrubbed out completely from the loaded organic phase using dilute sulfuric acid at pH ≤ 1.38. cobalt and manganese in the first extraction raffinate were extracted completely in four extraction stages at staggered pH values of 4.0, 4.4, 4.5, and 4.0 in the first, second, third, and fourth stages, respectively, using also 20vol% cyanex 272. A small amount of nickel（up to 6.6%） was co-extracted but was easily scrubbed out completely with dilute sulfuric acid at pH 2.0. A flow diagram showing the input and output conditions and the metals separated under the deduced optimum conditions is presented.

关键词： solvent extraction aluminum cobalt nickel nickel laterite ores

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Hg and As Minerals in Fluid Inclusions from the Williams Mine, Hemlo, and Their Genetic Implications

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chinese Journal Of Geochemistry 2002年第1期21卷 1-18页

作者：卢焕章 JAYANTA.GUHA don.c.HARRIS Sciences de la Terre Universite du Quebec a chicoutimi chicoutimi Quebec Canada G7H 2B 1 Geological Survey of canada 601 Booth Street Ottawa Ont. Canada K1A 0E8

The Hemlo mineralization is enigmatic compared to general Archean lode gold deposits based on the fact that it is characterized by an exotic mineralogy containing elements such as As, Hg, Sb, Ba, V and Mo. The genetic concepts range from syngenetic to epigenetic types of mineralization. This reconnaissance study was designed to examine the relationship of Hg-As minerals with respect to fluid inclusions in the Williams mine (formerly known as the Page Williams mine) covering the A and c ore zones.

关键词：流体包裹体含汞矿物含砷矿物矿化作用金矿床

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The cellular microenvironment and cytoskeletal actin dynamics in liver fibrogenesis

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BIOcELL 2022年第9期46卷 2003-2007页

作者： NOUR HIJAZI don c.roc.ey ZENGDUN SHI Medical University of South carolina Charleston29425USA

Hepatic stellate cells(HScs)are the primary effector cells in liver *** the normal liver,HScs serve as the primary vitamin A storage cells in the body and retain a“quiescent”***,after liver injury,they transdifferentiate to an“activated”myofibroblast-like phenotype,which is associated with dramatic upregulation of smooth muscle specific actin and extracellular matrix *** result is a fibrotic,stiff,and dysfunctional ***,understanding the molecular mechanisms that govern HSc function is essential for the development of anti-fibrotic *** actin cytoskeleton has emerged as a key component of the fibrogenic response in wound *** data indicate that the cytoskeleton receives signals from the cellular microenvironment and translates them to cellular function—in particular,increased type I collagen *** in nature,the actin cytoskeleton continuously polymerizes and depolymerizes in response to changes in the cellular *** this viewpoint,we discuss the recent developments underlying cytoskeletal actin dynamics in liver fibrosis,including how the cellular microenvironment affects HSc function and the molecular mechanisms that regulate the actininduced increase in collagen expression typical of activated HScs.

关键词： Extracellular matrix Actin dynamics Transcriptional regulation Signaling

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Predisposing factors’effects on mortality of oak (Quercus) and hickory (carya) species in mature forests undergoing mesophication in Appalachian Ohio

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Forest Ecosystems 2021年第1期8卷 81-94页

作者： don c.Radcliffe David M.Hix Stephen N.Matthews School of Environment and Natural Resources The Ohio State University2021 Coffey RoadColumbus OH 43210USA School of Environmental and Forest Sciences University of WashingtonBox 352100Seattle WA 98195-2100USA

Background:Mature oak(Quercus spp.)and hickory(carya spp.)trees are gradually being replaced by more shadetolerant tree species across the eastern U.S.,likely due to fire suppression and increased *** and hickories are highly valuable to wildlife;therefore,studying their mortality patterns can provide information on the longevity of habitat quality for many animal *** mortality has most often been studied following large oak decline events,but background mortality rates in forests with aging oak and hickory canopies warrant equal attention,especially in the context of widespread oak and hickory regeneration ***:We studied background mortality rates of five oak and one hickory species over a 23–25 year time period(1993–1995 to 2018),using 821/20th hectare permanent plots on the Marietta Unit of the Wayne National Forest in southeastern *** calculated mortality rates based on remeasurement of individual trees for white oak(Quercus alba),chestnut oak(Quercus montana),northern red oak(Quercus rubra),black oak(Quercus velutina),scarlet oak(Quercus coccinea),and pignut hickory(carya glabra).For each of these species other than scarlet oak,we also modeled the relationships of mortality probability with a priori topographic,soil,stand structural,and individual tree covariates,using a mixed-effects logistic regression ***:The species with the highest mortality rate was scarlet oak(61.3%),followed by northern red oak(41.4%),black oak(26.7%),pignut hickory(23.9%),white oak(23.4%),and chestnut oak(19.1%).In our models,northern red oak mortality was associated with more mesic slope positions,shallower solums,more acidic soils,and older stand *** hickory and chestnut oak mortality rates were associated with higher basal areas on the plot,while white oak mortality showed the opposite ***:Our data suggest that red oak subgenus trees in mature forests of our area will become increasingly uncommon relative t

关键词： Mortality Quercus carya Mesophication Wildlife habitat

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Approximate equivalence in von Neumann algebras

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Science china Mathematics 2005年第2期48卷 239-247页

作者： DING Huiru don Hadwin Department of Mathematics University of New HampshireDurhamNH03824USA Department of MathematicsUniversity of New HampshireDurhamNH03824USA

One formulation of D. Voiculescu's theorem on approximate unitary equivalence is that two unital representations π and ρ of a separable c*-algebra are approximately unitarily equivalent if and only if rank οπ = rank ορ. We study the analog when the ranges of π and ρ are contained in a von Neumann algebra R, the unitaries inducing the approximate equivalence must come from R, and 'rank' is replaced with 'R -rank' (defined as the Murray-von Neumann equivalence of the range projection).

关键词： approximate equivalence, R-rank.

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What can computational modeling offer for studying the ca^(2+) dysregulation in Alzheimer's disease:current research and future directions

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Neural Regeneration Research 2018年第7期13卷 1156-1158页

作者： Jingyi Liang don Kulasiri centre for Advanced computational Solutions(c-fAcS) Lincoln University

ca^2＋ dysregulation is an early event observed in Alzheimer＇s disease（AD） patients preceding the presence of its clinical *** of neuronalca^2＋ will cause synaptic loss and neuronal death,eventually leading to memory impairments and cognitive *** targetingca^2＋ signaling pathways are potential therapeutic strategies against *** complicated interactions make it challenging and expensive to study the underlying mechanisms as to how ca^2＋ signaling contributes to the pathogenesis of *** modeling offers new opportunities to study the signaling pathway and test proposed *** this mini-review,we present some computational approaches that have been used to study ca^2＋ dysregulation of AD by simulating ca^2＋signaling at various *** also pointed out the future directions that computational modeling can be done in studying the ca^2＋ dysregulation in AD.

关键词： Alzheimer's disease amyloid-beta ca^2+ hypothesis ca^2+ dysregulation computational modeling computational neuroscience

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Universal c*-algebras Defined by completely Bounded Unital Homomorphisms

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Acta Mathematica Sinica,English Series 2015年第12期31卷 1825-1844页

作者： Wen Hua QIAN don HADWIN Department of Mathematics East China University of Science and Technology Department of Mathematics and Statistics University of New Hampshire

Suppose A is a unital c＊-algebra and r *** this paper,we define a unital c＊-algebra c（cb）＊（A,r） and a completely bounded unital homomorphism αr：A → c（cb）＊（A,r）with the property that c（cb）＊（A,r）=c＊（αr（A））and,for every unital c＊-algebra B and every unital completely bounded homomorphism φ：A→ B,there is a（unique）unital ＊-homomorphism π：c（cb）＊（A,r）→B such thatφ=πoα*** prove that,if A is generated by a normal set {tλ：λ∈Λ},then c（cb）＊（A,r）is generated by the set {αr（tλ）：λ∈Λ}.By proving an equation of the norms of elements in a dense subset of c（cb）＊（A,r）we obtain that,if Β is a unital c＊-algebra that can be embedded into A,then c（cb）＊（B,r）can be naturally embedded into c（cb）＊（A,r）.We give characterizations of c（cb）＊（A,r）for some special situations and we conclude that c（cb）＊（A,r）will be ＂nice＂ when dim（A）≤ 2 and ＂quite complicated＂ when dim（A）≥ *** give a characterization of the relation between K-groups of A and K-groups of c（cb）＊（A,r）.We also define and study some analogous of c（cb）＊（A,r）.

关键词： completely bounded unital homomorphisms universal c*-algebras K-groups

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A Bishop-Stone-Weierstrass Theorem for (M_2(c))~n

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Acta Mathematica Sinica,English Series 2013年第8期29卷 1515-1534页

作者： Qi Hui LI don HADWIN Department of Mathematics East China University of Science and Technology Department of Mathematics and Statistics University of New Hampshire

In this paper, we shall give an elementary proof of a Bishop–Stone–Weierstrass theorem for （M2（c））n with respect to its pure states. To be more precise, we shall show that the pure-state Bishop hull of a unital ... 详细信息

关键词： Bishop–Stone–Weierstrass theorem pure states c*-algebras

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