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Neonatal colon perforation due to anorectal malformations: Can it be avoided?

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World Journal of Gastroenterology 2013年第25期19卷 3915-3917页

作者： Wei-dong Tong Kirk A ludwig Gastric and Colorectal division Department of Surgery Daping Hospital Third Military Medical University division of Colorectal Surgery Department of Surgery Medical College of Wisconsin

Anorectal malformations (ArM) are common anomalies in neonates. diagnostic and therapeutic delays in the management of ArM may lead to colonic perforation, and even death. Physical examination of the perineum is often sufficient to diagnose ArM in neonates. Notwithstanding, delayed diagnosis of ArM has become increasingly familiar to surgeons, as evidenced by the number of recent publications on this topic in the literature. In this commentary, we discuss spontaneous colonic perforation due to delayed diagnosis of ArM in neonates, and highlight the importance of early diagnosis in assuring good outcomes with surgical management. At this point, a thorough examination of the perineum during the initial newborn assessment is mandatory, particularly in those patients presenting with abdominal signs or symptoms.

关键词： Anorectal malformation Imperforate anus Bowel perforation Colon

Analysis of synthetic parameters for coating aluminum powders with phenyltriethoxysilane coupling agent and their effects on powder flow behavior

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Particuology 2024年第7期90卷 412-417页

作者： Lillian M.Mawby Bellamarie ludwig Benjamin J.Lear department of Chemistry The Pennsylvania State UniversityUniversity ParkPA16802USA Applied research Laboratory The Pennsylvania State UniversityUniversity ParkPA16802USA

Though silanization of aluminum powder is currently used to improve its flow properties,for use as an alternative fuel source,there are a wide range of experimental parameters for the process and not all of them have been thoroughly *** this is complete,it is unknown if the process is optimized in terms of time,efficiency,and ***,we report on a study into the effects of changes in humidity,degree of agitation,reaction temperature,and curing time upon the deposition of phenyl triethoxysilane into 20μm(d50)aluminum *** confirm the deposition of the coating via diffuse reflectance infrared spectroscopy and x-ray photoelectron *** then characterize the coated particles using apparent density measurements and Carney flow *** analysis of variance,we find that,of the parameters explored,only changes in cure time and reaction temperature provide meaningful changes to the apparent density,while none of our parameters produced statistically significant changes in Carney flow ***,we conclude that,when optimizing silanization of aluminum particles,environmental control of humidity is unneeded and that the reaction can be run with minimal *** ability to largely ignore these parameters is a benefit to large-scale processing.

关键词： Aluminum powder Silane Fluidization Apparent density Carney flow

Oligodendroglial heterogeneity in health,disease,and recovery:deeper insights into myelin dynamics

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Neural regeneration research 2025年第11期20卷 3179-3192页

作者： Pieter-Jan Serneels Julie d.de Schutter Lies de Groef Lieve Moons Steven Bergmans KU Leuven Leuven Brain InstituteDepartment of BiologyAnimal Physiology and Neurobiology DivisionNeural Circuit Development&Regeneration Research GroupLeuvenBelgium KU Leuven Leuven Brain InstituteDepartment of BiologyAnimal Physiology and Neurobiology DivisionCellular Communication&Neurodegeneration Research GroupLeuvenBelgium

decades of research asserted that the oligodendroglial lineage comprises two cell types:oligodendrocyte precursor cells and ***,recent studies employing single-cell rNA sequencing techniques have uncovered novel cell states,prompting a revision of the existing *** forward,the oligodendroglial lineage should be delineated into five distinct cell states:oligodendrocyte precursor cells,committed oligodendrocyte precursor cells,newly formed oligodendrocytes,myelin-forming oligodendrocytes,and mature *** new classification system enables a deeper understanding of the oligodendroglia in both physiological and pathological *** this uniform terminology will facilitate comparison and integration of data across ***,including the consolidation of findings from various demyelinating models,is essential to better understand the pathogenesis of demyelinating ***,comparing injury models across species with varying regenerative capacities can provide insights that may lead to new therapeutic strategies to overcome remyelination ***,by standardizing terminology and synthesizing data from diverse studies across different animal models,we can enhance our understanding of myelin pathology in central nervous system disorders such as multiple sclerosis,Alzheimer's disease,and amyotrophic lateral sclerosis,all of which involve oligodendroglial and myelin dysfunction.

关键词： animal models demyelination fish mammals multiple sclerosis myelin neurodegeneration oligodendrocytes oligodendroglial lineage remyelination

Numerical microstructure prediction for an aluminium casting and its experimental validation

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China Foundry 2011年第3期8卷 331-336页

作者： Unterreiter Guenter ludwig Andreas Wu Menghuai Materials Center Leoben Forschung GmbH Leoben Austria Chair for Simulation and Modelling of Metallurgical Processes Department of Metallurgy University of Leoben Leoben Austria

Virtual manufacturing based on through-process modelling becomes an evolving research area which aims at integrating diverse simulation tools to realize computer-aided design, analysis, prototyping and manufacturing. Numerical prediction of the as-cast microstructure is an initial and critical step in the whole through- process modelling chain for engineering components. A commercial software package with the capability of calculating important microstructure features for aluminium alloys is used to simulate a G-AISi7MgCu0.5 laboratory casting. The simulated microstructure, namely grain size, secondary dendrite arm spacing and diverse phase fractions are verified experimentally. Correspondence and discrepancies are reported and discussed.

关键词： numerical microstructure prediction aluminium casting through-process modelling

F）remature melt solidification during mold filling and its nfluence on the as-cast structure

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Frontiers of Mechanical Engineering 2018年第1期13卷 53-65页

作者： M. WU M. AHMAdEIN A. ludwig Chair for Simulation and Modeling of Metallurgical Processes University of Leoben Leoben A-8700 Austria Christian-doppler Laboratory for Advanced Process Simulation ofSolidification and Melting Department of Metallurgy University ofLeoben Leoben A-8700 Austria Production Engineering and Mechanical design department Faculty ofEngineering Tanta University Tanta 31111 Egypt

Premature melt solidification is the solidifica- tion of a melt during mold filling. In this study, a numerical model is used to analyze the influence of the pouring process on the premature solidification. The numerical model considers three phases, namely, air, melt, and equiaxed crystals. The crystals are assumed to have originated from the heterogeneous nucleation in the undercooled melt resulting from the first contact of the melt with the cold mold during pouring. The transport of the crystals by the melt flow, in accordance with the so- called ＂big bang＂ theory, is considered. The crystals are assumed globular in morphology and capable of growing according to the local constitutional undercooling. These crystals can also be remelted by mixing with the super- heated melt. As the modeling results, the evolutionary trends of the number density of the crystals and the volume fraction of the solid crystals in the melt during pouring are presented. The calculated number density of the crystals and the volume fraction of the solid crystals in the melt at the end of pouring are used as the initial conditions for the subsequent solidification simulation of the evolution of the as-cast structure. A five-phase volume-average model for mixed columnar-equiaxed solidification is used for the solidification simulation. An improved agreement between the simulation and experimental results is achieved by considering the effect of premature melt solidification during mold filling. Finally, the influences of pouring parameters, namely, pouring temperature, initial mold temperature, and pouring rate, on the premature melt solidification are discussed.

关键词： premature solidification mold filling as-caststructure modeling

development and characterization of stainless steel fiber-based copper-free brake liner formulation:A positive solution for steel fiber replacement

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Friction 2020年第2期8卷 396-420页

作者： Vijay r d.Lenin SINGArAVELU r.JAYAGANTHAN department of Production Engineering National Institute of TechnologyTiruchirappalli 620015Tamil NaduIndia department of Engineering design Indian Institute of Technology MadrasChennai 600036Tamil NaduIndia

This study deals with the development of drum brake liner for a multi-utility vehicle possessing a hydraulic brake system by varying 7 weight%of steel fiber and stainless steel fiber each,in friction composite *** developed friction composites were tested for physical,chemical,corrosion,mechanical,thermal properties,and tribological characteristics,under near-actual conditions using an inertia dynamometer as per industrial *** element analysis software(ANSYS)analysis was performed to show the thermal stress distribution of the developed friction composites at the maximum temperature rise due to heat generated during brake stops,and an extensive evaluation method was used to rank the *** study concludes that the brake factor of the stainless steel fiber-based friction composite produces stable performance in all conditions with a lower liner temperature rise of 340°C and lower thermal stress at 4.255294 ***,the steel fiber-based composites produced high performance at the beginning but deteriorated after a certain period due to higher levels of corrosion and a high temperature rise of 361°C resulting in a negative fade(-0.84%)and more thermal stress(5.619102 MPa).The primary plateau,secondary plateau,back transfer of drum wear debris,and the distribution of constituents on the worn surface of the developed composites in a resin matrix were identified and studied using a scanning electron microscope(SEM)equipped with energy-dispersive spectroscopy.

关键词： stainless steel fiber steel fiber brake liner friction composite

Mechanical and corrosion behaviour of hydroxyapatite reinforced Mg-Sn alloy composite by squeeze casting for biomedical applications

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Journal of Magnesium and Alloys 2020年第2期8卷 452-460页

作者： r radha d.Sreekanth School of Mechanical and Building Sciences Vellore Institute of TechnologyChennai 600127India

Magnesium alloys have gained increasing attention for biomedical applications due to their biocompatibility and the ***(HA)is known to be a highly bioactive because of its similar chemical and crystallographic structures to ***,HA is believed to be a potential ceramic material for the fabrication of Mg based composites,to combine the advantages of both Mg and ***,in general,the composites known to be more susceptible to corrosion attack than the matrix ***,in the present work,Sn is used as an alloying element to evaluate its effect on mechanical as well as corrosion properties of Mg/HA *** with 5 wt%HA and Mg-1 wt%Sn-5 wt%HA composites were prepared separately by stir assisted squeeze casting *** phase analysis and microstructure were characterized by X-ray diffraction(Xrd)and scanning electron microscope(SEM)coupled with energy dispersive spectroscopy(EdS)*** properties were evaluated by conducting the compression and micro hardness *** properties of as-cast composites were studied by linear polarization,Tafel and electrochemical impedance spectroscopy(EIS)*** results of both Xrd and SEM-EdS revealed that the main constitutional phases of as-cast Mg/HA composites were a-Mg and HA whereas,in Mg-Sn/HA composites,the phase Mg^Sn was observed along with fine distribution of HA *** both the cases,no interfacial reactions *** yield strength,ultimate compression strength and hardness were found to be increased with the addition of Sn in Mg/HA ***,the addition of Sn also played an important role in increasing the corrosion resistance of the Mg/HA composites which was attributed the refinement of grain size and the formation of Mg2Sn phase along the grain ***,it was concluded that the addition of Sn improves both mechanical and corrosion properties of Mg/HA composites.

关键词： Magnesium Composite Biomedical Corrosion Squeeze casting

Luminescence properties of Gd^(3+) containing glasses for ultra-violet(UV) light

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Journal of rare Earths 2014年第5期32卷 389-393页

作者： d.d.ramteke r.S.Gedam department of Applied Physics Visvesvaraya National Institute of Technology

Effect of Gd2O3 addition on optical properties of 27.5 Li2O-72.5 B2O3 glass systems was studied. density, differential thermal analysis （dTA）, optical absorption spectra and luminescence technique were used to characterize the prepared glasses. Emis- sion spectra showed two band 6p7/2→8S7/2 （311.5 nm） and 6p5/2→8S7/2 （305 nm） under the excitation of 274 nm. The intense emission at 311.5 nm suggested that these glasses could be useful as source of narrowband UV light.

关键词： glasses rare earths absorption band gap luminescence UV light

Electrical and optical properties of lithium borate glasses doped with Nd_2O_3

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Journal of rare Earths 2012年第8期30卷 785-789页

作者： r.S. Gedam d.d. ramteke department of Applied Physics Visvesvaraya National Institute of Technology

Glass series with general formula 25Li2O-（75-x）B2O3-xNd2O3 was prepared by conventional melt quench technique. Electrical and optical characterizations of these glasses were carried out. It was observed that conductivity of glasses decreased and activation energy in- creased with the addition of Nd2O3. The density and refractive index of the glasses increased while optical band gap and radiation length de- creased due to structural changes.

关键词： conductivity density refractive index optical absorption Tauc's plot rare earths