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Surgical management of peritonitis secondary to acute superior mesenteric artery occlusion

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World Journal of Gastroenterology 2014年第29期20卷 9936-9941页

作者： stefan Acosta Vascular Centre Malm?Sk?ne University Hospital

Diagnosis of acute arterial mesenteric ischemia in the early stages is now possible using modern computed tomography with intravenous contrast enhancement and imaging in the arterial and/or portal *** patients have acute superior mesenteric artery(SMA)occlusion,and a large proportion of these patients will develop peritonitis prior to mesenteric revascularization,and explorative laparotomy will therefore be necessary to evaluate the extent and severity of intestinal ischemia,and to perform bowel *** establishment of a hybrid operating room in vascular units in hospitals is most important to be able to perform successful intestinal *** review outlines current frontline surgical strategies to improve survival and minimize bowel morbidity in patients with peritonitis secondary to acute SMA *** laparotomy needs to be performed *** treatment is based upon intestinal revascularization followed by bowel *** no vascular imaging has been carried out,SMA angiography is *** case of embolic occlusion of the SMA,open embolectomy is performed followed by *** case of thrombotic occlusion,the occlusive lesion can be recanalized retrograde from an exposed SMA,the guidewire snared from either the femoral or brachial artery,and stented with standard devices from these access *** resections and sometimes gall bladder removal due to transmural infarctions are performed at initial laparotomy,leaving definitive bowel reconstructions to a planned second look laparotomy,according to the principles of damage control *** with peritonitis secondary to acute SMA occlusion should be managed by both the general and vascular surgeon,and a hybrid revascularization approach is of utmost importance to improve outcomes.

关键词： Acute mesenteric ischemia Peritonitis Explorative laparotomy Endovascular treatment Hybrid revascularization Superior mesenteric artery occlusion

Neutron diffraction studies on ‘‘simple'' iron oxides under pressure: Fe_3O_4, a-Fe_2O_3, and FeO

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Chinese Science Bulletin 2014年第36期59卷 5241-5250页

作者： stefan Klotz IMPMC CNRS UMR 7590 Universite' Pierre & Marie Curie75252 Paris France

Fe3O4(magnetite), a-Fe2O3(hematite), and Fe O(wu¨ stite) are the three major iron oxides and some of the most fundamental solids in nature. Interest in these systems is due to their abundance as minerals in the Earth and other telluric planets as well as their interesting electronic and magnetic properties which have been studied for decades. In this article, we review high-pressure studies on these three systems using neutron powder diffraction in the0–14 GPa range with a particular focus on the behavior of magnetism under pressure. Unpublished data on the pressure dependence of the Ne′el temperature in Fe O are presented. This review will give at the same time an introduction into technical aspects and illustrate the potential of high-pressure neutron scattering in the future.

关键词：四氧化三铁 α-氧化铁中子衍射 α-Fe2O3 磁压力 FeO 中子散射磁铁矿

Galerkin Spectral Method Applied to the Chemical Master Equation

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Communications in Computational Physics 2009年第5期5卷 871-896页

作者： stefan Engblom Department of Information Technology Uppsala UniversityP.O.Box 337SE-75105 UppsalaSweden

stochastic well-stirred chemically reacting systems can be accurately modeled by a continuous-time *** corresponding master equation evolves the system’s probability density function in time but can only rarely be explicitly *** investigate a numerical solution strategy in the form of a spectral method with an inherent natural adaptivity and a very favorable choice of basis *** results related to convergence have been developed previously and are briefly summarized while implementation issues,including how to adapt the basis functions to follow the solution they represent,are covered in more detail *** method is first applied to a model problem where the convergence can easily be *** we take on two more realistic systems from molecular biology where stochastic descriptions are often necessary to explain experimental *** conclusion is that,for sufficient accuracy demands and not too high dimensionality,the method indeed provides an alternative to other methods.

关键词： Master equation spectral-Galerkin method high dimensional problem moving basis chemical reactions

Role of Omicron variant of SARS-CoV-2 in children in Germany

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World Journal of Pediatrics 2022年第4期18卷 283-284页

作者： stefan Bittmann Department of Pediatrics Medical and Finance Center EpePed Mind Institute(PMI)Hindenburgring 448599 GronauGermany

A new variant of SARS-CoV-2,B.1.1.529 was first reported by the South African Department of Health on Nov 24,*** new variant was named as B.1.1.529 Omicron and was classified as a variant of concern(VOC)by the World Health Organization(WHO)on Nov 26,2021[1-13],Phylogenetic studies showed that Omicron arose independently of the currently dominant delta *** has an unusually high number of approximately 30 changes of amino acids in the spike protein compared with the original SARS-CoV-2,including those with known phenotypic impact(increase in transmission,immune evasion,and transmissibility),but significances of many mutations are still unclear[4-7].

关键词： Omi Phylogenetic children

Current treatment options and response rates in children with chronic hepatitis C

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World Journal of Gastroenterology 2012年第2期18卷 99-104页

作者： stefan Wirth Helios Medical Centre Wuppertal Department of PediatricsWitten-Herdecke UniversityD-42283 WuppertalGermany

Vertical transmission has become the most common mode of transmission of hepatitis C virus (HCV) in *** rate of perinatal transmission from an HCVinfected mother to her child ranges from 2% to 5% and the prevalence of HCV in children in developed countries ranges between 0.1% and 0.4%.Spontaneous viral clearance seems to be dependent on the genotype and has been reported between 2.4%-25%.For chronically infected patients,treatment with recombinant polyethylene glycol (PEG)-interferon α-2b and daily ribavirin has now been approved as standard treatment for children 2-17 years of *** five large prospective studies,a total of 318 children and adolescents aged 3-17 years were treated either with subcutaneous PEG-interferon α-2b at a dose of 1-1.5 μg/kg or 60 μg/m2 once a week in combination with oral ribavirin (15 mg/kg per day) or PEG-interferon α-2a with *** with genotype 1 and 4 received the medication for 48 wk and individuals with genotype 2 and 3 mainly for 24 *** sustained viral response (SVR) was achieved in 193/318 (60.7%) of treated *** for genotype;120/234 (51%) with genotype 1,68/73 (93%) with genotype 2/3,and 6/11 (55%) with genotype 4 showed *** rate was between 7.7% and 17%.Overall,treatment was well tolerated;how-ever,notable side effects were present in approximately 20%.According to recent experiences in the treatment of chronic hepatitis C in children and adolescents,a combination of PEG-interferon α with ribavirin has been found to be well tolerated and highly efficacious,particularly in individuals with genotype 2/***,this treatment can be recommended as standard of care until more effective treatment options will become available for genotype 1 patients.

关键词： Chronic hepatitis C Treatment Children Polyethylene glycol-interferon and ribavirin Responserate

MP-PIC simulation of circulating fluidized beds using an EMMS based drag model for Geldart B particles

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Particuology 2021年第6期19卷 76-90页

作者： Timo Dymala Tom Wytrwat stefan Heinrich Hamburg University of Technology Institute of Solids Process Engineering and Particle TechnologyDenickestr.1521073 HamburgGermany

In this study the multiphase particle-in-cell(MP-PIC)method is used for the simulation of two pilot-scale circulating fluidized beds(CFBs)with quartz sand belonging to Geldart’s group B as bed *** simulations were performed using a homogeneous drag model as well as a structure dependent drag model based on the energy minimization multi-scale method(EMMS).The results are compared with experimental data from literature as well as *** simulations with the EMMS based drag model show a good agreement of the time-averaged axial solids concentration,circulation rate and riser pressure ***,a lower grid sensitivity is observed compared to the homogeneous drag *** contrast to the conventional drag model a dense bottom zone is predicted by the EMMS based drag *** overprediction of the solid concentration in the dense bottom zone is presumably due to an overprediction of the cluster diameter that is calculated using an empirical cluster diameter *** shows the necessity for a new meso-scale cluster correlation for the simulation of Geldart B ***,the results of the time-averaged radial solids concentration differ from the expectations of a core-annulus flow indicating that a mesh refinement at the walls is ***,the importance of using a realistic particle size distribution is identified.

关键词： 3D-CFD simulation Circulating fluidized bed(CFB) Multiphase particle-in-cell method(MP-PIC) Energy minimizing multi-scale theory(EMMS) Validation study

A Design Concept and Kinematic Model for a Soft Aquatic Robot with Complex Bio-mimicking Motion

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Journal of Bionic Engineering 2022年第1期19卷 16-28页

作者： Shokoofeh Abbaszadeh Roberto Leidhold stefan Hoerner Institute of Electrical Power Systems Department of Electrical Engineering and Information TechnologyOtto-Von-Guericke University of MagdeburgUniversitätsplatz 239106MagdeburgGermany Institute of Fluid Dynamics and Thermodynamics Department of Process and Systems EngineeringOtto-Von-Guericke University of MagdeburgUniversitätsplatz 239106MagdeburgGermany

Fish mortality assessments for turbine passages are currently performed by live-animal testing with up to a hundred thousand fish per year in Germany.A propelled sensor device could act as a fish *** this context,the study presented here investigates the state of the art via a thorough literature review on propulsion systems for aquatic *** evaluation of propulsion performance,weight,size and complexity of the motion achievable allows for the selection of an optimal concept for such a fish mimicking device carrying the *** the second step,the design of a bioinspired soft robotic fish driven by an unconventional drive system is *** is based on piezoceramic actuators,which allow for motion with five degrees of freedom(DOF)and the creation of complex bio-mimicking body motions.A kinematic model for the motion’s characteristics is developed,to achieve accurate position feedback with the use of strain *** measurements validate the complex deformation of the body and deliver the basis for the calibration of the kinematic ***,it can be shown,that the calibrated model presented allows the tracking of the deformation of the entire body with an accuracy of 0.1 mm.

关键词： Unconventional drive system Biologically inspired robots Biomimetics Flexible robots

Urbanization between compactness and dispersion:designing a spatial model for measuring 2D binary settlement landscape configurations

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International Journal of Digital Earth 2019年第6期12卷 679-698页

作者： Hannes Taubenbock Michael Wurm Christian GeiB stefan Dech stefan Siedentop German Aerospace Center(DLR) German Remote Sensing Data Center(DFD)OberpfaffenhofenGermany ILS-Research Institute for Regional and Urban Development DortmundGermany

Measuring spatial patterns is a crucial task in spatial *** indicators have been developed to measure patterns in a quantitative ***,most comparative studies rely on relative comparisons,limiting their explanatory power to specific case *** by advancements in earth observation providing unprecedented resolutions of settlement patterns,this paper suggests a measurement technique for spatial patterns to overcome the limits of relative *** design a model spanning a feature space based on two metrics-largest patch index and number of *** feature space is defined as‘dispersion index’and covers the entire spectrum of possible two-dimensional binary(settlement)*** model configuration allows for an unambiguous ranking of each possible pattern with respect to spatial *** spatial resolutions of input data as well as selected areas of interest influence measurement results,we test dependencies within the ***,common other spatial metrics are selected for testing whether they allow unambiguous *** scenarios,we apply the model to artificially generated patterns representing all possible configurations as well as to real-world settlement classifications differing in growth dynamics and patterns.

关键词： Land cover spatial patterns landscape metrics dispersion index sensitivity analysis urban settlements remote sensing comparative spatial analysis

Predictions of the P1 approximation for radiative heat transfer in heterogeneous granular media

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Particuology 2023年第11期82卷 25-47页

作者： Jelena Macak Christoph Goniva stefan Radl DCS Computing GmbH 4020LinzAustria Graz University of Technology Institute of Process and Particle Engineering8010GrazAustria

The P1 approximation is a computationally efficient model for thermal ***,we present a P1 formulation in the context of the combined computational fluid dynamics and discrete element method(CFD-DEM),including closures for dependent scattering and *** available analytical and semi-analytical solutions,we find agreement for steady-state and transient quantities in sizedisperse *** flux is identified as the most sensitive quantity to predict,displaying unphysical spatial *** oscillations are due to a temperature slip at the locations of abrupt change in solid *** propose two techniques that mitigate this effect:smoothing of the radiative properties,and ***,using up to a million times enlarged particles,we demonstrate practically limitless compatibility with ***,we compare predictions made with our code to experimental data for a pebble bed under vacuum conditions,and in presence of *** find that a carefully calibrated simulation can replicate trends observed in experiments,with relative temperature error of less than 10%.

关键词： CFD-DEM Thermal radiation Coarse-graining P1 Pebble bed nuclear reactor