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Perforated jejunal ulcer associated with gastric mucosa in a jejunal diverticulum

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World Journal of Clinical Cases 2014年第6期2卷 209-210页

作者： john bunni Helen L Barrett Tim A Cook Department of Surgery Gloucester-shire Royal Hospital Department of Pathology Gloucestershire Royal Hospital

Jejunal diverticula are rare and subsequent complications even more so. The usual small bowel diverticulum encountered by general surgeons is a Meckel's. These are embryological remnants of the vitello-intestinal duct and are on the anti-mesenteric surface of the terminal ileum. They may contain heterotopic gastric or pancreatic mucosa. Herein we explore the case of a young girl who presented with features of peritonitis secondary to a complication from a jejunal diverticulum. The case, pathology, complications and treatment of jejunal diverticulosis and heterotopic gastric mucosa in the jejunum are explored.

关键词： Jejunum Perforation Heterotopic gastric mucosa Meckel’s gastrointestinal diverticulum

Dielectric confinement on exciton binding energy and nonlinear optical properties in a strained Zn_(1-x_(in))Mg_(x(in))Se/Zn_(1-x(out))Mg_(x(out))Se quantum well

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Journal of Semiconductors 2012年第9期33卷 1-7页

作者： J.Abraham Hudson mark A.john Peter Department of Physics NPR Arts&Science CollegeNathamDindigul-624401India Department of Physics Government Arts CollegeMelur-625106MaduraiIndia

The band offsets for a Zn1-xin Mgxin Se/Zn1-xout Mgxout Se quantum well heterostructure are determined using the model solid theory. The heavy hole exciton binding energies are investigated with various Mg alloy contents. The effect of mismatch between the dielectric constants between the well and the barrier is taken into account. The dependence of the excitonic transition energies on the geometrical confinement and the Mg alloy is discussed. Non-linear optical properties are determined using the compact density matrix approach. The linear, third order non-linear optical absorption coefficient values and the refractive index changes of the exciton are calculated for different concentrations of magnesium. The results show that the occurred blue shifts of the resonant peak due to the Mg incorporation give the information about the variation of two energy levels in the quantum well width.

关键词： interband emission energy exciton binding energy quantum well

Development of high damage threshold laser-machined apodizers and gain filters for laser applications

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High Power Laser Science and Engineering 2016年第3期4卷 113-119页

作者： Patrick Rambo Jens Schwarz mark Kimmel john L.Porter Sandia National Laboratories

We have developed high damage threshold filters to modify the spatial profile of a high energy laser beam. The filters are formed by laser ablation of a transmissive window. The ablation sites constitute scattering centers which can be filtered in a subsequent spatial filter. By creating the filters in dielectric materials, we see an increased laser-induced damage threshold from previous filters created using ‘metal on glass' lithography.

关键词： apodization laser beam shaping laser micro-machining spatial filtering

Alternative expressions for stand diameter in complex forests

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Forest Ecosystems 2023年第3期10卷 328-336页

作者： mark J.Ducey john A.Kershaw Jr. Department of Natural Resources and the Environment University of New HampshireDurhamNHUSA Faculty of Forestry and Environmental Management University of New BrunswickFrederictonNBCanada

Quadratic mean diameter is the most frequently reported descriptor of the diameter distribution of *** such,it is often used as an indicator of forest stand structure,developmental stage,and ecological and economic ***,quadratic mean diameter can be heavily influenced by the presence or absence of large numbers of small stems in lower canopy strata,and it is also sensitive to left-truncation of the diameter distribution,making its interpretation across inventories with different protocols ***,we examine three alternative expressions of stand diameter:the arithmetic and quadratic mean diameter of the thickest 100 trees per hectare,and the basal area-weighted mean *** data from the United States Forest Inventory and Analysis program for New York and New England,these alternative expressions showed closer correlation with multiple stand structural variables than did quadratic mean diameter,including merchantable cubic and board foot volume per hectare,aboveground live tree carbon per hectare,and total number of live and dead standing trees greater than 40 cm diameter at breast height per hectare(previously proposed as an index of old-growth structure).Arithmetic and quadratic mean diameter of the thickest 100 trees per hectare showed nearly identical performance,and the strongest correlations across the *** develop closed-form expressions for these variables when the diameter distribution is a Weibull,and illustrate their behavior relative to quadratic mean diameter for that *** the reasons for prevalence of quadratic mean diameter as an indicator remain valid,we suggest that these alternative measures should be more widely reported and analyzed to give a more informative depiction of stand structure and development in complex forests.

关键词： Forest structure Diameter at breast height Weibull distribution

Strength and Toughness of Steel Fibre Reinforced Reactive Powder Concrete Under Blast Loading

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Transactions of Tianjin University 2006年第B09期12卷 70-74页

作者： KUZNETSOV Valerian A REBENTROST mark WASCHL john Weapons Systems Division DSTOEdinburgh SA 5111Australia VSL Australia Noble Park VIC 3174Australia

The blast resistance of structures used in buildings needs to be investigated due to the increased threat of a terrorist attack. The damage done by Composition B or Powergel to steel fibre reinforced reactive powder concrete （SFRPC） panels and ordinary reinforced concrete （RC） panels of equivalent static flexural strength is compared. A 0. 5 kg charge was detonated at a distance of 0. 1 m from the 1. 3 m × 1. 0 m × 0. 1 m （thick） panels, which were simply supported and spaning 1.3 m. Dynamic displacement measurements, high-speed video recording and visual examination of the panels for spall and breach were undertaken. The SFRPC panels withstood the bare charge blast better than the reinforced ordinary concrete panels. Neither type of panel was breached using a O. 5 kg charge, The RC panel exhibited more spalling when Composition B was used. Under successive Composition B loading conditions, the RC panel was breached. In comparison the SFRPC panel was not breached. Exposure to fragmenting charge loading conditions confirmed these performance differences between the SFRPC panel and the reinforced ordinary concrete panel.

关键词： steel fibre reinforced reactive powder concrete blast loading spalling explosive blast loading

Metrological framework for selecting morphological characters to identify species and estimate developmental maturity of forensically significant insect specimens

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Forensic Sciences Research 2021年第1期6卷 75-83页

作者： john mark Midgley Martin Herrer Villet Southern African Forensic Entomology Research Laboratory Department of Zoology and EntomologyRhodes UniversityMakhandaSouth Africa Department of Natural Sciences KwaZulu-Natal MuseumPietermaritzburgSouth Africa

Accurate age estimates of immature necrophagous insects associated with a human or animal body can provide evidence of how long the body has been *** estimates are based on species-specific details of the insects’aging processes,and therefore require accurate species identification and developmental stage *** professionals who produce or use identified organisms as forensic evidence have little training in taxonomy or metrology,and appreciate the availability of formalized principles and standards for biological *** identifications are usually most readily and economically made using categorical and qualitative morphological characters,but it may be necessary to use less convenient and potentially more ambiguous characters that are continuous and quantitative if two candidate species are closely related,or if identifying developmental stages within a *** should be selected by criteria such as taxonomic specificity and metrological repeatability and relative *** propose such a hierarchical framework,critique various measurements of immature insects,and suggest some standard approaches to determine the reliability of organismal identifications and measurements in estimating postmortem *** criteria for good characters include high repeatability(including low scope for ambiguity or parallax effects),pronounced discreteness,and small relative error in *** same principles apply to individuation of unique objects in general.

关键词： orensic sciences forensic entomology identification individuation data types metrology measurement error repeatability

Carbon Supply and the Regulation of Cell Wa Synthesis

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Molecular Plant 2018年第1期11卷 75-94页

作者： Jana Verbancic john Edward Lunn mark Stitt Staffan Persson Max Planck Institute of Molecular Plant Physiology Am Muhlenberg 1 14476 Potsdam-Golm Germany School of Biosciences University of Melbourne Parkville VIC 3010 Australia

All plant cells are surrounded by a cell wall that determines the directionality of cell growth and protects the cell against its environment. Plant cell walls are comprised primarily of polysaccharides and represent the largest sink for photosynthetically fixed carbon, both for individual plants and in the terrestrial biosphere as a whole. Cell wall synthesis is a highly sophisticated process, involving multiple enzymes and metabolic intermediates, intracellular trafficking of proteins and cell wall precursors, assembly of cell wall polymers into the extracellular matrix, remodeling of polymers and their interactions, and recycling of cell wall sugars. In this review we discuss how newly fixed carbon, in the form of UDP-glucose and other nucleotide sugars, contributes to the synthesis of cell wall polysaccharides, and how cell wall synthesis is influenced by the carbon status of the plant, with a focus on the model species Arabidopsis （Arabidopsis thaliana）.

关键词： carbon availability cell walls nucleotide sugars sucrose synthase

Jejunal diverticulosis found in a patient with long-standing pneumoperitoneum and pseudo-obstruction on imaging:a case report

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Gastroenterology Report 2016年第4期4卷 337-340,I0003页

作者： Carolyn Hanna john Mullinax mark S Friedman Julian Sanchez USF Morsani College of Medicine TampaFLUSA Department of Surgical Oncology Moffitt Cancer CenterTampaFLUSA

Small bowel diverticulosis is a rare finding within the general population and jejunal diverticulosis,specifically,is even *** manifestations can range from post-prandial pain,constipation and malabsorption to serious complications,such as gastro-intestinal hemorrhage,perforation and acute intestinal *** we describe the case of an 81-yearold gentleman who presented with a three-year history of abdominal pain and weight *** unremarkable physical examination and laboratory tests,persistent pneumoperitoneum and dilated loops of small bowel were found on *** been given a diagnosis of small bowel bacterial overgrowth,the patient underwent capsule endoscopy study for further evaluation of his small *** capsule did not reach the colon and the patient never noted passing the capsule in his stool so,six months post-procedure,a computed tomography(CT)scan seemed to reveal the retained *** exploratory laparotomy revealed 200 cm of atonic,dilated jejunum with impressive diverticula along the antimesenteric *** case report is an example of an unusual set of presenting signs and symptoms of jejunal diverticulosis,including persistent pneumoperitoneum,pseudo-obstruction and small bowel bacterial overgrowth.A literature review has revealed that these signs have been present in other cases of jejunal diverticulosis,although the etiology and pathophysiology is not clearly understood.

关键词： Jejunal diverticulosis pneumoperitoneum pseudo-obstruction

Effect of Cooling Rate on the Room Temperature Microstructure Following the Intercritical Deformation of Steel S460

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Journal of Iron and Steel Research International 2011年第S1期18卷 500-505页

作者： Hinton john S Palmiere Eric J Rainforth W.mark IMMPETUS Dept.Of Materials Science and EngineeringThe University of SheffieldMappin StSheffieldSouth YorkshireS1 3JDUK

The effect of final hot rolling in the intercritical (α+γ) region on microstructure and properties is very specific to the individual processing conditions and the chemical composition of a steel.S460 is a plate steel processed in this *** reproduce at the laboratory scale,a multi-stage simulation was developed which included a high temperature austenite deformation and an isothermal *** effect of the applied cooling rate following intercritical deformation was *** 1K/s (typical industrial cooling) the microstructure was similar to the reference sample,but included an intragranular ferrite *** was due to differences in processing history,and considered to be linked to a larger prior austenite grain *** an accelerated cooling rate (15K/s),acicular ferrite formed on shear bands within the strained austenite *** scans have been completed to provide further information about the microstructures,with band contrast able to identify the pearlite phase at the slowest cooling *** is a starting point from which to focus on the ferrite morphologies.

关键词： intercritical deformation cooling rate laboratory simulation plate steel acicular ferrite