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2.
Nat Commun ; 14(1): 2516, 2023 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-37130885

RESUMO

In the quest of new materials that can withstand severe irradiation and mechanical extremes for advanced applications (e.g. fission & fusion reactors, space applications, etc.), design, prediction and control of advanced materials beyond current material designs become paramount. Here, through a combined experimental and simulation methodology, we design a nanocrystalline refractory high entropy alloy (RHEA) system. Compositions assessed under extreme environments and in situ electron-microscopy reveal both high thermal stability and radiation resistance. We observe grain refinement under heavy ion irradiation and resistance to dual-beam irradiation and helium implantation in the form of low defect generation and evolution, as well as no detectable grain growth. The experimental and modeling results-showing a good agreement-can be applied to design and rapidly assess other alloys subjected to extreme environmental conditions.

3.
Sci Rep ; 9(1): 4759, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30886191

RESUMO

This study investigates the microstructural evolution and mechanical response of sputter-deposited amorphous silicon oxycarbide (SiOC)/crystalline Fe nanolaminates, a single layer SiOC film, and a single layer Fe film subjected to ion implantation at room temperature to obtain a maximum He concentration of 5 at. %. X-ray diffraction and transmission electron microscopy indicated no evidence of implantation-induced phase transformation or layer breakdown in the nanolaminates. Implantation resulted in the formation of He bubbles and an increase in the average size of the Fe grains in the individual Fe layers of the nanolaminates and the single layer Fe film, but the bubble density and grain size were found to be smaller in the former. By reducing the thicknesses of individual layers in the nanolaminates, bubble density and grain size were further decreased. No He bubbles were observed in the SiOC layers of the nanolaminates and the single layer SiOC film. Nanoindentation and scanning probe microscopy revealed an increase in the hardness of both single layer SiOC and Fe films after implantation. For the nanolaminates, changes in hardness were found to depend on the thicknesses of the individual layers, where reducing the layer thickness to 14 nm resulted in mitigation of implantation-induced hardening.

4.
J Anim Sci ; 93(10): 4977-83, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26523590

RESUMO

This study investigated effects of stocking rate on cattle performance, quality and quantity of corn residue, and impact of residue removal on grain yield for 5 yr at the University of Nebraska - Lincoln West Central Water Resources Field Laboratory near Brule, NE. Four removal treatments-1) no removal (control), 2) grazing at 2.5 animal unit month (AUM)/ha, 3) grazing at 5.0 AUM/ha, and 4) baling-were applied to a center pivot-irrigated corn field (53 ha). The field was divided into eight 6.6-ha paddocks to which replicated treatments were assigned. Samples of residue were collected in October and March (before and after residue removal) using ten 0.5-m quadrats per treatment replication. Residue was separated into 5 plant parts-stem, cob, leaf, husk, and grain-and analyzed for nutrient content. Esophageally fistulated cattle were used to measure diet quality. Cattle assigned to the 2.5 AUM/ha stocking rate treatment gained more BW ( < 0.01) and BCS ( < 0.01) than cattle assigned to the 5.0 AUM/ha treatment. Leaf contained the most ( < 0.01) CP and husk had the greatest ( < 0.01) in vitro OM disappearance (IVOMD) but the CP and IVOMD of individual plant parts did not differ ( > 0.69) between sampling dates. Amount of total residue was reduced ( < 0.05) by baling and both grazing treatments between October and March but was not different ( > 0.05) in control paddocks between sampling dates. As a proportion of the total residue, stem increased ( < 0.01) and husk decreased ( < 0.01) between October and March. Diet CP content was similar ( = 0.10) between sampling dates for the 2 grazing treatments but IVOMD was greater after grazing in the 2.5 AUM/ha grazing treatment ( = 0.04). Subsequent grain yields were not different ( = 0.16) across all 4 residue removal treatments. At the proper stocking rate, corn residue grazing results in acceptable animal performance without negatively impacting subsequent corn grain production.


Assuntos
Agricultura/métodos , Ração Animal/análise , Bovinos/fisiologia , Dieta/veterinária , Zea mays , Fenômenos Fisiológicos da Nutrição Animal , Animais
5.
J Urol ; 145(6): 1256-60, 1991 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2033706

RESUMO

The characteristics of eosinophilic ureteritis and idiopathic segmental ureteritis are sufficiently overlapping and so uncommonly reported as to raise a nosological issue. In an attempt to address that question, we compared 2 new cases and 8 previous reports of eosinophilic ureteritis with a series of 21 idiopathic segmental ureteritis patients. One of our patients also had renal pelvic involvement, while 1 is the youngest (3 years old) patient reported and the first instance of bilateral eosinophilic ureteritis. Our review found that eosinophilic ureteritis largely occurs in atopic or hypereosinophilic syndromes, often with a traumatic history. Eosinophilic and idiopathic segmental ureteritis causes ureteral obstruction due to mural involvement. However, eosinophilic ureteritis never forms an intraluminal mass and is not associated with mucosal ulceration. In addition, we found no case reported with features that bridge the 2 conditions. We conclude that the clinical and pathological features of eosinophilic and idiopathic segmental ureteritis are sufficiently distinct to separate the 2 conditions.


Assuntos
Eosinofilia/complicações , Doenças Ureterais/etiologia , Adulto , Pré-Escolar , Eosinofilia/patologia , Feminino , Humanos , Masculino , Doenças Ureterais/patologia
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