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Shielding AZ91D-1%Ca from corrosion through ultrasound melt treatment:A study for stent design

Journal of Magnesium and Alloys 2023年第8期11卷 2901-2915页

作者： I.V.Gomes M.Pacheco M.Nienaber S.C.Neves D.Mei a.barros R.L.Reis J.L.Alves H.Puga CMEMS–UMinho University of MinhoGuimarãesPortugal LABBELS–Associate Laboratory BragaGuimarãesPortugal B's Research Group-Research Institute on Biomaterials Biodegradables and BiomimeticsUniversity of MinhoHeadquarters of the European Institute of Excellence on Tissue Engineering and Regenerative MedicineAvepark-Parque de Ciência e TecnologiaBarco GuimarãesPortugal ICVS/3B's-PT Government Associate Laboratory BragaGuimarãesPortugal Institute of Material and Process Design Helmholtz-Zentrum HereonGeesthacht 21502Germany School of Materials Science and Engineering&Henan Key Laboratory of Advanced Magnesium Alloy Zhengzhou UniversityZhengzhou 450001China

Magnesium-based materials show great potential for producing biodegradable stents,but their high corrosion rates are a *** study investigates whether ultrasound melt treatment can change the corrosion response of an extruded AZ91D-1.0%Ca(wt.%)in Earle's Balanced Salt Solution by tailoring the intermetallics'morphology in the as-extruded *** results showed that the wires from ultrasound-treated ingots corroded faster than non-treated ones in immersion for up to 6 *** trend shifted for longer periods,and ultrasound-treated material showed lower corrosion rates and uniform corrosion,while the non-treated material displayed localized corrosion *** testing of the wires demonstrated that immersion in EBSS lowered the tensile strength and elongation at fracture due to material degradation,regardless of the processing ***,this decline was sharper in the non-treated *** findings suggest that ultrasound melt processing can be a promising method for improving the corrosion resistance of magnesium-based materials,paving the way for their use in manufacturing biodegradable stents.

关键词： Magnesium Ultrasound treatment Stent Corrosion Mechanical properties

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Understanding the corrosion of Mg alloys in in vitro urinary tract conditions: A step forward towards a biodegradable metallic ureteral stent

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Journal of Magnesium and Alloys 2023年第11期11卷 4301-4324页

作者： Margarida Pacheco Ivo M.Aroso Joana M.Silva Sviatlana V.Lamaka Jan Bohlen Maria Nienaber Dietmar Letzig Estêvão Lima Alexandre a.barros Rui L.Reis 3B’s Research Group-Research Institute on Biomaterials Biodegradables and BiomimeticsUniversity of MinhoGuimarãesPortugal ICVS/3B’s-PT Government Associate Laboratory Braga/GuimarãesPortugal Institute of Surface Science Helmholtz-Zentrum hereon GmbHGermany Institute of Material and Process Design Helmholtz-Zentrum hereon GmbHGermany School of Health Sciences Life and Health Sciences Research Institute(ICVS)University of MinhoBragaPortugal

Ureteral stents play a fundamental role in modern time urology. However, following the deployment, stent-related symptoms are frequent and affect patient health and quality of life. Using biodegradable metals as ureteral stent materials have emerged as a promising strategy, mainly due to the improved radial force and slower degradation rate expected. Therefore, this study aimed to characterize different biodegradable metals in urinary tract environment to understand their propensity for future utilization as base materials for ureteral stents. The corrosion of 5 Mg alloys - AZ31, Mg-1Zn, Mg-1Y, pure Mg, and Mg-4Ag - under simulated urinary tract conditions was accessed. The corrosion layer of the different alloys presented common elements, such as Mg(OH)_(2), MgO, and phosphate-containing products, but slight variations in their chemical compositions were detected. The corrosion rate of the different metals varied, which was expected given the differences in the corrosion layers. On top of this, the findings of this study highlighted the significant differences in the samples' corrosion and corrosion layers when in stagnant and flowing conditions. With the results of this study, we concluded that Mg-1Zn and Mg-4Ag presented a higher propensity for localized corrosion, probably due to a less protective corrosion layer;Mg-4Ag corroded faster than all the other four alloys,and Mg-1Y stood out due to its distinct corrosion pattern, that showed to be more homogeneous than all the other four samples, making this one more attractive for the future studies on biodegradable metals.

关键词： Biodegradable metals Magnesium alloys Localized corrosion Biodegradable metallic ureteral stent

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Ultrastructural features of the hypopharyngeal glands in the social wasp Polistes versicolor （Hymenoptera： Vespidae）

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Insect Science 2008年第3期15卷 277-284页

作者： Fabio barros Britto Flavio Henrique Caetano Universidade Estadual Paulista Julio de Mesquita Filho Instituto de Bioci~ncias de Rio Claro - Depto. de Biologia Rio Claro SP Brazil

The wasps of the genus Polistes have been considered the key to understanding the evolution of social behavior in Hymenoptera. Several studies have shown that the development of organized insect societies was accompanied by the evolution of structures like exocrine glands, which became specialized to perform specific functions. This article investigates the ultrastructural and cytochemical features of the hypopharyngeal glands of Polistes versicolor. These glands have been studied in depth in social bees, where they occur only in nurses and produce the royal jelly. Our results＇ revealed that these glands basically did not vary among individuals or between sexes. They are constituted by spherical cells, each with a large nucleus and well-developed rough endoplasmic reticulum. Secretion vesicles are abundant, but lipid droplets were not observed, indicating that these glands may not have a role in pheromone synthesis. Acid phosphatase was detected in lysosomes, and also flee in the cytosol, but did not seem to be related with cell death. Thus, our results suggest that the hypopharyngeal glands ofP. versicolor may not have a specialized social role, but could produce digestive enzymes.

关键词： cellular cycle cytochemistry hypopharyngeal glands morphology Polistes,wasps

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Assessment of alterability of basalt used for riprap by petrographic examination

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 208-213页

作者： Maria Heloisa.barros de Oliveira Frascá MHB Geological Services

All engineering projects consist of several steps, and one of the main tasks is to identify and characterize the most important features of rock types that will be excavated, crushed, or mined for any particular usage purpose, from a single residential building to major works of infrastructure. Laboratory investigation on engineering geology is thus conducted in order to determine the most relevant rock properties when designing structures such as mining shafts, tunnels, buildings, or reservoir dams to be built in sites associated with rocks. A wide range of laboratory tests is available, making the correct choice of test methods greatly relevant to determine the key property for the planned use of the rock. This paper is an illustrative case of laboratory testing of basaltic rocks to be used as riprap in a reservoir dam. It shows the important role of the petrographic study carried out to analyze the distribution pattern of smectite clay minerals. Test results are explained for the assessment of rock alterability, an essential aspect for the selection of the most suitable basalt variety for the envisaged conditions of use.

关键词： Rock properties Laboratory testing Test methods Petrographic analysis Smectite clay minerals Basaltic rocks Accelerated weathering tests Alterability

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A hybrid Monte Carlo study of bond-stretching electron–phonon interactions and charge order in BaBiO_(3)

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npj Computational Materials 2023年第1期9卷 1950-1958页

作者： Benjamin Cohen-Stead Kipton barros Richard Scalettar Steven Johnston Department of Physics and Astronomy The University of TennesseeKnoxvilleTN 37996USA Institute for Advanced Materials and Manufacturing The University of TennesseeKnoxvilleTN 37996USA Theoretical Division and CNLS Los Alamos National LaboratoryLos AlamosNM 87545USA Department of Physics and Astronomy University of CaliforniaDavisCA 95616USA

The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains *** address this question using nonperturbative hybrid Monte Carlo calculations for the parent compound BaBiO_(3).Our model includes the Bi 6s and O 2pσorbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping *** simulate three-dimensional clusters of up to 4000 orbitals,with input model parameters taken from ab initio electronic structure calculations and a phonon energyℏΩ0=60 *** results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system,despite a relatively small dimensionless *** also find that the transition deviates from the weak-coupling Peierls’*** work demonstrates that off-diagonal e-ph interactions in orbital space are vital in establishing the bismuthate phase diagram.

关键词： stretching phonon charge

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Major regulatory mechanisms involved in sperm motility

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Asian Journal of Andrology 2017年第1期19卷 5-14页

作者： Rute Pereira Rosalia Sa Alberto barros Mario Sousa Department of Microscopy Laboratory of Cell Biology Institute of Biomedical Sciences Abel Salazar University of Porto (ICBAS-UP) Rua Jorge Viterbo Ferreira 2284050-313 Porto Portugal and Multidisciplinary Unit for Biomedical Research-UMIB ICBAS-UP Centre for Reproductive Genetics Alberto barros Av. do Bessa 2401° Dto. Frente 4100-012 Porto Portugal Department of Genetics Faculty of Medicine University of Porto. Alameda Prof. Hernani Monteiro 4200-319 Porto Portugal and Institute of Health Research an Innovation (13S) University of Porto Portugal.

The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies.

关键词： antioxidants calcium membrane channels protein kinases sperm genetic abnormalities sperm motility

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Integrated operational planning of hydrothermal power and natural gas systems with large scale storages

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Journal of Modern Power Systems and Clean Energy 2017年第3期5卷 299-313页

作者： Diego Mauricio OJEDA-ESTEYBAR Ricardo German RUBIO-barros Alberto VARGAS Instituto de Energı´a Ele´ctrica(IEE) Universidad Nacional de San Juan(UNSJ)Consejo Nacional de Investigaciones Cientı´ficas y Tecnolo´gicas(CONICET)Av.Libertador Gral.San Martı´n West 11095400 San JuanArgentina

The growing installation of natural gas fired power plants has increased the integration of natural gas and electricity sectors. This has driven the need investigate the interactions among them and to optimize energy resources management from a centralized planning perspective. Thus, a combined modeling of the reservoirs involved in electric power and gas systems and their locations on both networks are essential features to be considered in the operational planning of energy *** paper presents a modeling and optimization approach to the operational planning of electric power and natural gas systems, taking into account different energy storage facilities, such as water reservoirs, natural gas storages and line packs of pipelines. The proposed model takes advantage of captures both energy systems synergy and their associated networks. This approach identifies the interactions between the energy storage facilities and their economic impact over their optimal scheduling. The results show the benefits of an integrated operational planning of electric power and natural gas systems, the close interdependency between the energy resources stored in both systems, and the effects of a combined scheduling.

关键词： Energy storage Hydrothermal scheduling Integrated operational planning Integrated energy systems Natural gas

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Perianal disease in inflammatory bowel disease:Broadening treatment and surveillance strategies for anal cancer

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World Journal of Gastroenterology 2024年第28期30卷 3373-3385页

作者： Tatiana Pacheco Sara Monteiro Luísa.barros Jorge Silva Department of Gastroenterology Centro Hospitalar do Tamega e SousaPenafiel 4560-136Portugal

The perianal disease affects up to one-third of individuals with Crohn's disease(CD),causing disabling symptoms and significant impairment in quality of life,particularly for those with perianal fistulising CD(PFCD).The collaborative effort between gastroenterologists and surgeons is essential for addressing PFCD to achieve fistula closure and promote luminal *** fistula healing rates with conventional therapies have prompted the emergence of new biological agents,endoscopic procedures and surgical techniques that show promising *** these,mesenchymal stem cells injection is a particularly hopeful *** addition to the burden of fistulas,individuals with perianal CD may face an increased risk of developing anal *** underscores the importance of surveillance programmes and timely interventions to prevent late diagnoses and poor ***,there is no established formal anal screening *** this review,we provide an overview of the current state of the art in managing PFCD,including novel medical,endoscopic and surgical *** discussion also focuses on the relevance of establishing an anal cancer screening programme in CD,intending to propose a risk-based surveillance *** validation of this surveillance programme would be a significant step forward in improving patient care and outcomes.

关键词： Inflammatory bowel disease Crohn's disease Perianal Fistula Anus diseases Management Anal cancer Screening

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Gastrointestinal motility and absorptive disorders in patients with inflammatory bowel diseases: Prevalence, diagnosis and treatment

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World Journal of Gastroenterology 2019年第31期25卷 4414-4426页

作者： Luísa Leite barros Alberto Queiroz Farias Ali Rezaie Department of Gastroenterology University of Sao Paulo School of MedicineSao Paulo 05403-000Brazil Division of Gastroenterology Department of MedicineCedars Sinai Medical CenterLos AngelesCA 90048United States

Inflammatory bowel diseases(IBD),Crohns disease and ulcerative colitis,are chronic conditions associated with high morbidity and healthcare *** natural history of IBD is variable and marked by alternating periods of flare and *** though the use of newer therapeutic targets has been associated with higher rates of mucosal healing,a great proportion of IBD patients remain symptomatic despite effective control of *** symptoms may include but not limited to abdominal pain,dyspepsia,diarrhea,urgency,fecal incontinence,constipation or *** this setting,commonly there is an overlap with gastrointestinal(GI)motility and absorptive *** recognition of these conditions greatly improves patient care and may decrease the risk of ***,in this review we describe the prevalence,diagnosis and treatment of GI motility and absorptive disorders that commonly affect patients with IBD.

关键词： Inflammatory bowel diseases Crohn’s disease Ulcerative colitis Gastrointestinal motility and absorptive disorders Irritable bowel syndrome Small intestinal bacterial overgrowth Small intestinal fungal overgrowth Dyssynergic defecation Fecal incontinence Chronic intestinal pseudo-obstruction

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Super-low friction of ta-C coating in presence of oleic acid

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Friction 2014年第2期2卷 156-163页

作者： Makoto KANO Jean Michel MARTIN Kentaro YOSHIDA Maria Isabel DE barros BOUCHET Division of Mechanical&Material Engineering Kanagawa Industrial Technology Center705-1 Shimo-ImaizumiEbinaKanagawaJapan LTDS Ecole Centrale de Lyon 69380EcullyFrance

Friction tests have been carried out on bearing steel friction pairs coated with a-C:H and ta-C under lubricated conditions with 1-hexadecene and pure oleic acid,*** results show that ta-C leads to the super-low regime with oleic acid(friction coefficient below 0.01)and that a-C:H is quite well lubricated by *** analyses by coupling X-ray photoelectron spectroscopy(XPS)and secondary ion mass spectrometry(SIMS)have been carried out in the case of oleic acid with ta-C and a-C:H *** show that tribochemical reactions have *** groups terminate the ta-C surface whereas a-C:H is covered by a thin tribofilm and is terminated by oleic acid *** superlow regime in the case of ta-C is mainly attributed to the presence of the OH-termination.

关键词： epoxy composite short carbon fiber friction wear

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