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Current developments in pediatric liver transplantation

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World Journal of Hepatology 2015年第11期7卷 1509-1520页

作者： Christina Hackl Hans J Schlitt martin loss Birgit Knoppke Michael Melter Department of Surgery University Hospital Regensburg KUNO-Children’s University Hospital Regensburg

In 1953, the pioneer of human orthotopic liver transplantation(LT), Thomas E Starzl, was the first to attempt an orthotopic liver transplant into a 3 years old patient suffering from biliary atresia. Thus, the first LT in humans was attempted in a disease, which, up until today, remains the main indication for pediatric LT(p LT). During the last sixty years, refinements in diagnostics and surgical technique, the introduction of new immunosuppressive medications and improvements in perioperative pediatric care have established LT as routine procedure for childhood acute and chronic liver failure as well as inherited liver diseases. In contrast to adult recipients, p LT differs greatly in indications for LT, allocation practice, surgical technique, immunosuppression and postoperative life-long aftercare. Many aspects are focus of ongoing preclinical and clinical research. The present review gives an overview of current developments and the clinical outcome of p LT, with a focus on alternatives to full-size deceased-donor organ transplantation.

关键词： Pediatric liver transplantation Deceasedorgan donation Living donor liver transplantation Splitliver transplantation Biliary atresia

Turbulence model performance for ventilation components pressure losses

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Building Simulation 2022年第3期15卷 389-399页

作者： Karsten Tawackolian martin Kriegel Hermann-Rietschel-Institut EnergyComfort&Health in BuildingsTU BerlinGermany

This study looks to find a suitable turbulence model for calculating pressure losses of ventilation *** building ventilation,the most relevant Reynolds number range is between 3×10^(4) and 6×10^(5),depending on the duct dimensions and airflow *** loss coefficients can increase considerably for some components at Reynolds numbers below 2×10^(5).An initial survey of popular turbulence models was conducted for a selected test case of a bend with such a strong Reynolds number *** of the turbulence models failed in reproducing this dependence and predicted curve progressions that were too flat and only applicable for higher Reynolds *** effects near walls played an important role in the present *** turbulence modelling,near-wall damping functions are used to account for this influence.A model that implements near-wall modelling is the lag elliptic blending k-ε*** model gave reasonable predictions for pressure loss coefficients at lower Reynolds *** example is the low Reynolds number k-εturbulence model of Wilcox(LRN).The modification uses damping functions and was initially developed for simulating profiles such as aircraft *** has not been widely used for internal flows such as air duct *** on selected reference cases,the three closure coefficients of the LRN model were adapted in this work to simulate ventilation *** predictions were obtained with new coefficients(LRNM model).This underlined that low Reynolds number effects are relevant in ventilation ductworks and give first insights for suitable turbulence models for this *** the lag elliptic blending model and the modified LRNM model predicted the pressure losses relatively well for the test case where the other tested models failed.

关键词： HVAC ductwork CFD simulation turbulence model model calibration

Xerotolerant foliar endophytic fungi of Populus euphratica from the Tarim River basin,Central China are conspecific to endophytic ITS phylotypes of Populus tremula from temperate Europe

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Fungal Diversity 2012年第3期54卷 133-142页

作者： martin Unterseher Anne Petzold martin Schnittler Institute of Botany and Landscape Ecology Department of Systematic BotanyErnst-Moritz-Arndt UniversityGrimmer Str.8817487 GreifswaldGermany

Fungal research on non-lichenized taxa in xeric and other unusual habitats for fungi is comparatively scarce but constantly reveal an enormous ecological and functional adaptiveness of these organisms to *** holds true in the topmost forest canopies as well as in marine,arctic,antarctic or desert *** the present study dried leaves of Populus euphratica from a continental desert area in Central China were investigated for endophytic fungi 6 weeks after sampling by cultivation of small leaf ***-five species,many of them well-known from extreme environments,were delimitated from as few as 58 isolates by a combined analysis of morphotypes,micromorphology and ITS ***-analyses revealed pronounced conspecificity to endophytes from Populus tremula leaves,but significant differences to foliar endophytic assemblages in Pinus monticola and Fagus *** deduced high similarity of endophytic communities on both Populus species compared with that on Pinus and Fagus suggests that many fungal phyllosphere species show a well-pronounced host preference,at least for their endophytic *** addition,it demonstrates that leaving leaves as a microhabitat might provide similar conditions such as constantly high relative humidity,regardless of the surrounding climatic *** evolution of extremotolerance might be of particular importance for retaining competitiveness of foliar endophytes in deciduous host trees after loss of pathogenicity.

关键词： Frost-drought tolerance Extremophile Alternaria Cladosporium Penicillium Evolution of endophytism

Empirical Model for the Quantitative Prediction of losses of Radial Fans based on CFD Calculations

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Journal of Thermal Science 2013年第4期22卷 304-310页

作者： Heiko Ratter Saban Caglar martin Gabi Institute of Fluid Machinery Karlsruhe Institute of Technology Kaiserstrasse 1276131 Karlsruhe Germany

In a classical layout process of a fan the quantity of losses is estimated as a sum and expressed in the overall efficiency rote However the characteristic of the pressure rise, the losses and the efficiency rate beside the design point is not known. Against this background a numerical model was developed to calculate quantitative values of occurring losses at radial fan impellers at an early stage in the design process. It allows to estimate the pressure rise and efficiency rate of a given fan geometry at and beside the design point. The physics of losses are described in literature, but obtaining quantitative values is still a challenge. As common in hydraulic theory the losses are calculated with analytic formulas supported by coefficients and efficiency rates, which have to be determined empirically. This paper shows the method how to determine the coefficients for a given radial fan. Therefore a representative radial fan with backward curved blades was designed in reference to classical design guidelines. Performance measuring was done conform to ISO 5801. The flow was calculated at 8 different operation points using CFD methods. The RANS equations are solved by using the SST-k-omega turbulence model. The flow do- main consists of one blade section including inlet channel and outflow chamber. Spatial discretization is done by a block-structured mesh of approx. 1.8 million cells. Performance data show a very good agreement between measurement and calculation.

关键词： loss model radial fan CFD RANS

Influence of individual tree characteristics,spatial structure and logging history on tree-related microhabitat occurrence in North American hardwood forests

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Forest Ecosystems 2021年第2期8卷 357-372页

作者： Maxence martin Patricia Raymond Yan Boucher Département des Sciences fondamentales Université du Québec à Chicoutimi555boul.de l’UniversitéChicoutimiQuébec G7H 2B1Canada Institut de la recherche sur les forêts Université du Québec en Abitibi-Témiscamingue445boul.de l’UniversitéRouyn-NorandaQuébec J9X 5E4Canada Centre d'étude de la forêt Université du Québec à MontréalP.O.Box 8888Centre-ville StationMontréalQuébec H3C 3P8Canada Direction de la recherche forestière Ministère des Forêtsde la Faune et des Parcs(MFFP)2700rue EinsteinQuébecQuébec G1P 3W8Canada

Background:Tree-related microhabitats(hereafter,"TreMs")are key components of forest biodiversity but they are still poorly known in North American hardwood *** spatial patterns of living trees bearing TreMs(hereafter,"TreM-trees")also remain to be *** logging practices can lead to a loss of TreM-trees and of their associated biodiversity,it is essential to identify the factors explaining TreM occurrence to better integrate them into forest *** therefore inventoried TreMs in 40.5-ha survey strips in northern hardwood forests in Quebec,Canada,while recording the spatial location of each *** strips were located in unmanaged oldgrowth forests,and 2 were in forests managed under selection *** 4 stands were dominated by sugar maple(Acer saccharum Marsh.)and American beech(Fagus grandifolia Ehrn.).Beech bark disease,an exotic pathology,was observed in all the ***:Large diameter at breast height and low tree vigor were the main characteristics explaining the presence of TreMs at the tree ***-trees presented slight spatial aggregation *** aggregates,however,were not well-defined and were generally constituted by a large number of trees bearing few different types of *** TreM classes(broken branch or top and woodpecker lodge)also presented a spatial *** practices had no significant effect on TreM *** bark disease increased the frequency of senescent *** impact of this pathology on TreMs was however mitigated by the small size of infected trees and probably by the short time elapsed since its ***:The factors explaining the presence and abundance of TreMs on trees has so far been little studied in North American hardwood *** results highlight that TreM-tree characteristics in the surveyed forests are consistent with those of previous studies conducted in other forest types and regions(e.g.,Europe or Northwestern America).To our knowledge,th

关键词： Habitat trees Wildlife habitat Northern hardwoods Old-growth forest Selection cutting Ecosystembased management Biodiversity indicators Conservation Forest management

Strength, deformability and permeability of kakiritic rocks from the Gotthard base tunnel

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2224-2237页

作者： martin Vogelhuber Erich Pimentel Georgios Anagnostou ETH Zurich ZurichSwitzerland

The 57-km long,new Gotthard Base Tunnel(GBT)crosses over a 1.1-km long stretch containing kakirites,*** rocks which,depending on the degree of tectonisation,may exhibit severe squeezing behaviour upon tunnel *** tunnel stretch was already identified as a key problem in the early planning phase,necessitating intensive geological exploration and laboratory investigations over a 14-year period,including research and development in experimental *** laboratory investigations for the GBT provided not only a considerable amount of data about the geotechnical parameters of the kakirites,but also valuable information about their basic behaviour and the adequacy of various testing techniques for this type of ***,by using specially designed testing equipment and procedures,it was shown that,(1)conventional rock mechanics triaxial tests cannot provide reliable results for kakirites;(2)the kakirites obey the principle of effective stress in Terzaghi’s classical form and consequently it is indispensable to measure the pore pressure during triaxial testing,analogously to the consolidated drained(CD)and consolidated undrained(CU)tests in soil mechanics;(3)the effects of a possible loss of water and desaturation during sampling,transport,storage and preparation of specimens can be successfully mitigated by subjecting the specimens to flow-through before the actual triaxial testing;and,(4)CD tests on partially saturated specimens that are obtained by means of flow-through can provide reliable and reproducible *** saves a significant amount of time,allows a greater number of tests to be performed,and allows results to be obtained more quickly,which is particularly important for decision-making during tunnel advance.

关键词： Squeezing Pore pressure Triaxial testing

Biomaterials for spinal cord repair

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Neuroscience Bulletin 2013年第4期29卷 445-459页

作者： Agnes E. Haggerty martin oudega Departments of Bioengineering University of Pittsburgh Departments of the Center for the Neural Basis of Cognition University of Pittsburgh Departments of Physical Medicine and Rehabilitation University of Pittsburgh Departments of Neurobiology University of Pittsburgh

Spinal cord injury （SCI） results in permanent loss of function leading to often devastating personal, economic and social problems. A contributing factor to the permanence of SCI is that damaged axons do not regenerate, which prevents the re-establishment of axonal circuits involved in function. Many groups are working to develop treatments that address the lack of axon regeneration after SCI. The emergence of biomaterials for regeneration and increased collaboration between engineers, basic and translational scientists, and clinicians hold promise for the development of effective therapies for SCI. A plethora of biomaterials is available and has been tested in various models of SCI. Considering the clinical relevance of contusion injuries, we primarily focus on polymers that meet the specific criteria for addressing this type of injury. Biomaterials may provide structural support and/or serve as a delivery vehicle for factors to arrest growth inhibition and promote axonal growth. Designing materials to address the specific needs of the damaged central nervous system is crucial and possible with current technology. Here, we review the most prominent materials, their optimal characteristics, and their potential roles in repairing and regenerating damaged axons following SCI.

关键词： spinal cord injury axon regeneration biodegradable materials extracellular matrix proteins functionalrecovery growth factor guidance injury and repair spinal motor neuron

Pneumatic Measurements Downstream of a Radial Turbine Nozzle Cascade

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Journal of Thermal Science 2010年第1期19卷 42-46页

作者： martin LUXA Rudolf DVORAK David SIMURDA Jan VIMMR Department of Fluid Dynamics Institute of Thermomechanicsv.v.i.Academy of Science of the Czech RepublicPragueCzech Republic Department of Mechanics University of West Bohemia in PilsenPlzeňCzech Republic

This paper deals mainly with pneumatic measurements on a radial turbine nozzle cascade. The fill radial cascade guarantees the exit flow field periodicity downstream of it. A special traversing mechanism with a five - hole conical probe moving along a circular path behind the cascade was used for flow field investigation in this type of cascade with very low aspect ratio. The analyses of results of 2D and 3D pneumatic measurements including loss coefficient values are presented.

关键词： radial turbine cascade aspect ratio pneumatic measurement loss coefficient

Spontaneous Otoacoustic Emissions in Tinnitus Patients

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Journal of Otology 2006年第1期1卷 35-39页

作者： William martin Department of Otolaryngology Head & Neck Surgery Oregon Health & Science University3181 SW Sam Jackson Park Road Portland Oregon 97239 USA

Otoacoustic emissions (OAEs) are believed to be the products of active cochlear mechanics. They are generally associated with relatively intact outer hair cell function. OAEs usually decrease or become undetectable when hearing loss of cochlear origin exceeds 40-50 dB HL. Subjective tinnitus is a perception of sound without detectable corresponding source. It is most often seen in patients with hearing loss. It is also frequently seen in patients with head injuries. Studies have suggested that the prevalence of spontaneous otoacoustic emissions(SOAEs) is lower in patients with hearing loss and tinnitus than in normal population. There have also been reports on association between tinnitus and SOAEs of unusually high amplitudes, which can be controlled by aspirin administration. The current paper is a preliminary review of clinical data collected from a group of tinnitus patients in an attempt to elucidate on the relationship between SOAEs and tinnitus from a clinical point of view. Audiometric, tinnitus and SOAE data from 59 patients seen at the Oregon Health & Science University Tinnitus Clinic were retrospectively studied. Fifty-four of these 59 patients showed sensorineural hearing loss of various degrees at the time of evaluation, mostly affecting high frequencies. SOAEs were detected in 26 ears (22%) of 18 patients(30.5%). There was no difference in SOAE prevalence between male and female patients. SOAEs were recorded in four of the five patients whose pure tone thresholds were within normal limits up to 8000 Hz. SOAEs appeared to be recorded at a higher rate in patients whose tinnitus started following motor vehicle accidents or head injuries(5/10) than in other patients. Time course of tinnitus did not appear to affect SOAE detection rate. There were no correlations between SOAE frequency and matched tinnitus pitch or frequency of maximum hearing loss. Significance of these findings is discussed.

关键词： tinnitus otoacoustic emissions