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The role of L-arginine metabolism in neurocritical care patients

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Neural Regeneration Research 2022年第7期17卷 1446-1453页

作者： Marius marc-Daniel Mader Patrick Czorlich Department of Neurosurgery University Medical Center Hamburg-EppendorfHamburgGermany Institute for Stem Cell Biology and Regenerative Medicine Stanford University School of MedicineStanfordCAUSA

Nitric oxide is an important mediator of vascular autoregulation and is involved in pathophysiological changes after acute neurological *** oxide is generated by nitric oxide synthases from the amino acid L-arginine.L-arginine can also serve as a substrate for arginases or lead to the generation of dimethylarginines,asymmetric dimethylarginine,and symmetric dimethylarginine,by *** dimethylarginine is an endogenous inhibitor of nitric oxide synthase and can lead to endothelial *** review discusses the role of L-arginine metabolism in patients suffering from acute and critical neurological disorders often requiring neuro-intensive care *** addressed in this review include intracerebral hemorrhage,aneurysmal subarachnoid hemorrhage,and traumatic brain *** therapeutic advances in the field are described including current randomized controlled trials for traumatic brain injuries and hemorrhagic stroke.

关键词： arginine brain injuries,traumatic cerebral hemorrhage dimethylarginine nitric oxide stroke subarachnoid hemorrhage

PERMEABILITY COMPUTATION ON A REPRESENTATIVE VOLUME ELEMENT （RVE） OF. UNIDIRECTIONAL DISORDERED FIBER ARRAYS

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Journal of Computational Mathematics 2016年第3期34卷 223-239页

作者： Karim Hitti Stephanie Feghali marc Bernacki Department of Mathematics Faculty of Sciences University of Balamand Lebanon Notre Dame University-Louaize Faculty of Natural and Applied Sciences Department of Mathematics and Statistics Lebanon Lebanese University Faculty of Sciences II Mathematics Department P.O. Box 90656 Fanar-Matn Lebanon Mines-ParisTech PSL-Research University CEMEF- Centre de mise en forme des matdriaux CNRS UMR 7635 CS 10207 rue Claude Daunesse 06904 Sophia Antipolis Cedex France

An efficient method to compute the permeability of disordered fibrous arrays is pro- posed. A stabilized mixed finite element method is used with an immersed domain ap- proach to represent the porous material at its microscopic scale. Therefore, the Stokes e- quations are solved in the whole domain （including solid part） using a penalization method. The accuracy is controlled by refining the mesh around the fluid-solid interface defined by a level-set function. Using homogenization techniques, the permeability of an RVE is obtained. Furthermore, a new method to generate disordered fibers in function of the porosity, Ф, and other microstructural parameters is proposed and a study of the effect of inter-fiber spacing on K：, the permeability tensor, is performed using parallel computation and over 460 simulations were carried RVEs consisting of over 555 fibers. This task was achieved out in two-dimensional

关键词： Permeability Fibrous Media Finite Element Method Level-set.

Geometry optimization of a barrel silicon pixelated tracker

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Chinese Physics C 2017年第8期41卷 118-124页

作者：刘清源王萌 marc Winter School of Physics and Key Laboratory of Particle Physics and Particle Irradiation(MOE) Shandong UniversityJinan 250100China Universite de Strasbourg IPHC-CNRS23 rue du Loess67037 StrasbourgFrance

We have studied optimization of the design of a barrel-shaped pixelated tracker for given spatial boundaries. The optimization includes choice of number of layers and layer spacing. Focusing on tracking performance only,momentum resolution is chosen as the figure of merit. The layer spacing is studied based on Gluckstern＇s method and a numerical geometry scan of all possible tracker layouts. A formula to give the optimal geometry for curvature measurement is derived in the case of negligible multiple scattering to deal with trajectories of very high momentum particles. The result is validated by a numerical scan method, which could also be implemented with any track fitting algorithm involving material effects, to search for the optimal layer spacing and to determine the total number of layers for the momentum range of interest under the same magnetic field. The geometry optimization of an inner silicon pixel tracker proposed for BESIII is also studied by using a numerical scan and these results are compared with Geant4-based simulations.

关键词： tracker geometry optimization optimal spacing numerical scan least squares kalman filter initialization BESIII silicon pixel tracker

Enhancing the performance of porous silicon biosensors:the interplay of nanostructure design and microfluidic integration

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Microsystems & Nanoengineering 2024年第4期10卷 211-224页

作者： Kayan Awawdeh marc AButtkewitz Janina Bahnemann Ester Segal Faculty of Biotechnology and Food Engineering Technion—Israel Institute of Technology320003 HaifaIsrael Institute of Technical Chemistry Leibniz Universität Hannover30167 HannoverGermany Institute of Physics University of Augsburg86159 AugsburgGermany Centre for Advanced Analytics and Predictive Sciences(CAAPS) University of Augsburg86159 AugsburgGermany

This work presents the development and design of aptasensor employing porous silicon(PSi)Fabry‒Pérot thin films that are suitable for use as optical transducers for the detection of lactoferrin(LF),which is a protein biomarker secreted at elevated levels during gastrointestinal(GI)inflammatory disorders such as inflammatory bowel disease and chronic *** overcome the primary limitation associated with PSi biosensors—namely,their relatively poor sensitivity due to issues related to complex mass transfer phenomena and reaction kinetics—we employed two strategic approaches:First,we sought to optimize the porous nanostructure with respect to factors including layer thickness,pore diameter,and capture probe ***,we leveraged convection properties by integrating the resulting biosensor into a 3D-printed microfluidic system that also had one of two different micromixer architectures(i.e.,staggered herringbone micromixers or microimpellers)*** demonstrated that tailoring the PSi aptasensor significantly improved its performance,achieving a limit of detection(LOD)of 50 nM—which is>1 order of magnitude lower than that achieved using previously-developed biosensors of this ***,integration into microfluidic systems that incorporated passive and active micromixers further enhanced the aptasensor’s sensitivity,achieving an additional reduction in the LOD by yet another order of *** advancements demonstrate the potential of combining PSi-based optical transducers with microfluidic technology to create sensitive label-free biosensing platforms for the detection of GI inflammatory biomarkers.

关键词： porous integration fluid

Optimal flow conditions of a tracheobronchial model to reengineer lung structures

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Acta Mechanica Sinica 2017年第2期33卷 284-294页

作者： Stefano Casarin Federico Aletti Giuseppe Baselli marc Garbey LASIE UMR CNTS Univeristy of La Rochelle La Rochelle France Houston Methodist Hospital Research Institute Houston TX USA Dipartimento di Elettronica Informazione e Bioingegneria Politecnico di Milano Milan Italy

The high demand for lung transplants cannot be matched by an adequate number of lungs from donors. Since fully ex-novo lungs are far from being feasible, tissue engineering is actively considering implantation of engineered lungs where the devitalized structure of a donor is used as scaffold to be repopulated by stem cells of the receiving patient. A decellularized donated lung is treated inside a bioreactor where transport through the tracheobronchial tree (TBT) will allow for both deposition of stem cells and nourishment for their subsequent growth, thus developing new lung tissue. The key concern is to set optimally the boundary conditions to utilize in the bioreactor. We propose a predictive model of slow liquid ventilation, which combines a one-dimensional (1-D) mathematical model of the TBT and a solute deposition model strongly dependent on fluid velocity across the tree. With it, we were able to track and drive the concentration of a generic solute across the airways, looking for its optimal distribution. This was given by properly adjusting the pumps’ regime serving the bioreactor. A feedback system, created by coupling the two models, allowed us to derive the optimal pattern. The TBT model can be easily invertible, thus yielding a straightforward flow/pressure law at the inlet to optimize the efficiency of the bioreactor.

关键词： Bioreactor Lung rehabilitation Network flow Tissue engineering Transport of solute

Fabrication of a three-dimensional micro/nanocarbon structure with sub-10 nm carbon fiber arrays based on the nanoforming and pyrolysis of polyacrylonitrile-based jet fibers

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Microsystems & Nanoengineering 2023年第5期9卷 333-343页

作者： Jufeng Deng Chong Liu Dian Song marc Madou Key Laboratory of Advanced Manufacturing Technology of the Ministry of Education Guizhou UniversityGuiyangChina School of Mechanical Engineering Dalian University of TechnologyDalianChina Chemical and Biomolecular Engineering University of CaliforniaIrvineUSA Mechanical and Aerospace Engineering University of CaliforniaIrvineUSA School of Engineering and Science Tecnologico de MonterreyMonterreyMexico

To produce a three-dimensional micro/nanocarbon structure,a manufacturing design technique for sub-10 nm carbon fiber arrays on three-dimensional carbon micropillars has been developed;the method involves initiating electrostatic jetting,forming submicron-to-nanoscale PAN-based fibers,and maximizing the shrinkage from polyacrylonitrile(PAN)-based fibers to carbon *** and nanodepositing methods for polyacrylonitrilebased jet fibers as precursors of carbon fibers are proposed for the processing design of electrostatic jet initiation and for the forming design of submicron-to-nanoscale PAN-based fibers by establishing and analyzing mathematical models that include the diameter and tensile stress values of jet fibers and the electric field intensity values on the surfaces of carbon *** accordance with these methods,an array of jet fibers with diameters of~80 nm is experimentally formed based on the thinning of the electrospinning fluid on top of a dispensing needle,the poking of drum into an electrospinning droplet,and the controlling of the needle–drum *** converting thin PANbased jet fibers to carbon fibers,a pyrolysis method consisting of the suspension of jet nanofibers between carbon micropillars,the bond between the fibers and the surface of the carbon micropillar,and the control of micropillar spacing,stabilization temperature,and carbonation rate is presented to maximize the shrinkage from PAN-based fibers to carbon fibers and to form sub-10 nm carbon fiber arrays between three-dimensional carbon *** manufacturing design of a three-dimensional micro/nanocarbon structure can produce thin PAN-based jet nanofibers and nanofiber arrays aligned on micropillar surfaces,obtain shrinkage levels reaching 96%and incorporate sub-10 nm carbon fibers into three-dimensional carbon micropillars;these actions provide new research opportunities for correlated three-dimensional micro/nanocarbon structures that have not previousl

关键词： fibers fiber carbon

Fabrication of crystalline submicro-to-nano carbon wire for achieving high current density and ultrastable current

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Microsystems & Nanoengineering 2022年第1期8卷 223-235页

作者： Jufeng Deng Chong Liu Dian song marc Madou School of Mechanical Engineering Dalian University of TechnologyDalian 116023China Mechanical and Aerospace Engineering University of CaliforniaIrvineCA 92617USA Chemical and Biomolecular Engineering University of CaliforniaIrvineCA 92517USA School of Engineering and Science Tecnologico de MonterreyMonterreyNM 64849Mexico

Crystalline carbon nanowire arrays were fabricated taking advantage of near-field electrospinning and stress decyanation.A novel fabrication method for carbon nanowires with radii ranging from~2.15μm down to~25 nm was developed based on implementing nitrogen pretreatment on the silica surface and then aligning polymer nanofibers during near-field electrospinning at an ultralow *** decyanation was implemented by subsequently pyrolyzing a polymer nanofiber array on the silica surface at 1000°C for 1 h in an N_(2)atmosphere,thus obtaining a crystalline carbon nanowire array with a nanostructured *** crystalline nanostructures were fabricated on the nanowire surface,and their electrochemical performance was evaluated by cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS).Crystalline carbon wires with diameters ranging from micrometers to submicrometers displayed carbon nanoelectrode-like behavior with their CV curve having a sigmoidal shape.A highly crystalline carbon nanowire array showed distinct behavior,having a monotonically increasing straight line as its CV curve and a semicircular EIS spectrum;these results demonstrated its ultrastable current,as determined by electron ***,nanocrystalline-structured carbon wires with diameters of~305 nm displayed at least a fourfold higher peak current density during CV(4000 mA/m2)than highly crystalline carbon nanowires with diameters of~100 nm and porous microwires with diameters of~4.3μm.

关键词： nanowires crystalline carbon

Effect of Bifidobacterium longum 35624 on disease severity and quality of life in patients with irritable bowel syndrome

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World Journal of Gastroenterology 2022年第7期28卷 732-744页

作者： Jean-marc Sabaté Franck Iglicki Department of Gastroenterology Hôpital AvicenneAP-HPSorbonne Paris NordBobigny 93000France INSERM U-987 Pathophysiology and Clinical Pharmacology of PainAmbroise ParéHospitalBoulogne-Billancourt 92100France allée Léon Gambetta Clichy 92110France

BACKGROUND Bifidobacterium longum 35624 has shown efficacy in improving irritable bowel syndrome(IBS)symptoms compared with placebo in double-blind randomized ***,few data are available from real-life clinical practice or from studies that used Rome IV criteria to diagnose *** To assess the effect of *** 35624 on IBS severity and quality of life in a reallife *** From November 2018 to January 2020,278 patients with IBS(according to Rome IV criteria)were enrolled in a prospective,open-label,multicenter observational study by private practice gastroenterologists to received one capsule of *** 35624(10^(9) colony-forming units)per day for 30 *** in the study was independently proposed to patients during spontaneous *** severity(assessed by the IBS severity scoring system)and patient quality of life(assessed by the IBS quality of life questionnaire)were compared between the inclusion visit(baseline)and the visit at the end of 30 d of *** characteristics of patients were described at *** variables comparisons between inclusion and end-of-treatment visits were performed using the t-test and Kruskal-Wallis *** variables comparisons were performed using theχ^(2) *** total of 233 patients,with a mean age of 51.4 years and composed of 71.2%women,were included in the *** these patients,48.1%had moderate IBS and 46.4%had severe *** a 30-d treatment period with one *** 35624 capsule per day,a significant decrease in IBS severity was observed compared to baseline(mean±SD,IBS severity scoring system scores:208±104 vs 303±81,P<0.001)and 57%of patients moved to lower severity categories or achieved *** quality of life of patients was also improved by the treatment(IBS Quality of Life questionnaire score:68.8±20.9 vs 60.2±20.5;P<0.001)and 63.8%of patients were satisfied with the *** Thirty days of treatment with *** 35624

关键词： Irritable bowel syndrome Probiotics Bifidobacterium longum Quality of life Severity of illness index Abdominal pain

Effect of slab width on choice of appropriate casting speed in steel production

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Journal of Iron and Steel Research International 2022年第1期29卷 71-79页

作者： Daniel Christopher Merten marc-Thorsten Hütt Yilmaz Uygun Department of Mathematics and Logistics Jacobs University BremenBremen 28759Germany Department of Life Sciences and Chemistry Jacobs University BremenBremen 28759Germany

In steel continuous casting(CC),the choice of the appropriate speed at which the slab is cast can be influenced by many different factors and *** the slab thickness seems to have the biggest impact,other features like the slab width have been consistently *** fact,the slab width practically limits the casting speed via the mass flow constraint which governs the input and output balance at the ***,we present a case study that aims at analyzing steel production data from the perspective of casting speed *** studying the speed fluctuations of an industrial CC machine,we identify a strategic regime change toward a stricter consideration of the mass flow *** regime change manifests itself in a significant increase in the correlation between the actual casting speed and the maximal speed associated with the mass flow *** the surface,taking greater account of the input and output balance at the tundish has reduced the productivity of the continuous caster;however,one can argue that the lessened yield is compensated by a diminished risk of eventual slab *** the perspective of this trade-off,we establish a visualization technique that enables us to pinpoint the boundary beyond which one strategic regime becomes economically more advantageous than the other.

关键词： Continuous casting Casting speed Slab width Slab thickness Mass flow constraint Machine length constraint