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Design multifunctional Mg–Zr coatings regulating Mg alloy bioabsorption

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Journal of Magnesium and Alloys 2024年第4期12卷 1461-1478页

作者： Zohra Benzarti Sandesh Itani JoséDavid Castro Sandra carvalho ana Sofia Ramos University of Coimbra CEMMPREARISEDepartment of Mechanical EngineeringRua Luís Reis Santos3030-788CoimbraPortugal Laboratory of Multifunctional Materials and Applications(LaMMA) Department of PhysicsFaculty of Sciences of SfaxUniversity of SfaxSoukra Road km 3.5B.P.1171Sfax3000Tunisia

Magnesium(Mg)alloys are widely used for temporary bone implants due to their favorable biodegradability,cytocompatibility,hemocompatibility,and close mechanical properties to ***,rapid degradation and inadequate strength limit their *** overcome this,the direct current magnetron sputtering technique is employed for surface coating in Mg-based alloys using various zirconium(Zr)*** approach presents a promising strategy for simultaneously improving corrosion resistance,maintaining biocompatibility,and enhancing strength without compromising *** leveraging Mg’s inherent biodegradability,it has the potential to minimize the need for secondary surgeries,thereby reducing costs and *** paper is a systematic study aimed at understanding the corrosion mechanisms of Mg–Zr coatings,denoted Mg-xZr(x=0–5 at.%).Zr-doped coatings exhibited columnar growth leading to denser and refined structures with increasing Zr *** analysis confirmed the presence of the Mg(00.2)basal plane,shifting towards higher angles(1.15°)with 5 at.%Zr doping due to lattice parameter changes(i.e.,decrease and increase of“c”and“a”lattice parameters,respectively).Mg–Zr coatings exhibited“liquidphilic”behavior,while Young’s modulus retained a steady value around 80 GPa across all ***,the hardness has significantly improved across all samples’coating,reaching the highest value of(2.2±0.3)GPa for 5 at.%*** testing in simulated body fluid(SBF)at 37℃ revealed a significant enhancement in corrosion resistance for Mg–Zr coatings containing 1.0–3.4 at.%*** with the 5 at.%Zr coating which exhibited a corrosion rate of 32 mm/year,these coatings displayed lower corrosion rates,ranging from 1 to 12 mm/*** synergistic enhancement in mechanical properties and corrosion resistance,achieved with 2.0–3.4 at.%Zr,suggests potential ability for reducing stress shielding and controlled degradation performance,and consequentl

关键词： Mg-Zr coatings Magnetron sputtering Nanoindentation Corrosion resistance Bone implants

Robotic Surgery: An Effective Treatment Option for Epiphrenic Diverticulum Associated with Nutcracker Esophagus

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Surgical Science 2024年第1期15卷 1-6页

作者： Augusto Tinoco Gilberto carvalho Leonardo Tinoco ana Paula Quintão Department of Digestive Surgery Hospital S&#227o Jos&#233 do Ava&#237 Itaperuna Brazil

Background: Epiphrenic Diverticulum is frequently associated with esophageal motility disorders, such as nutcrackers esophagus. The diagnosis is usually made using imaging studies such as a Barium esophagogram, and esophageal manometry. Surgical treatment options for epiphrenic diverticulum and EN include diverticulectomy and wide myotomy. Aim: The resection of three epiphrenic diverticula and extensive myotomy were performed by robotic thoracoscopy uneventfully. Case presentation: A 65-year-old female complaining of dysphagia for solid foods, Chest pain and regurgitation. Esophagogastroduodenoscopy (EDG) with difficulty in advancing the endoscope at 25 cm and demonstrating an ED, no hiatal hernia and normal stomach and duodenum. Barium Esophagogram showed multiple diverticula and tortuosity throughout the esophagus. Conclusion: With robotic surgery, surgeons can perform highly precise operations with enhanced 3D vision and control. Through this cutting-edge approach, the treatment of ED associated with EN can be drastically changed, promising better outcomes for patients.

关键词： Robotic Surgery Myotomy Nutcracker Esophagus Epiphrenic Diverticulum

Robotic Surgery: An Effective Treatment Option for Epiphrenic Diverticulum Associated with Nutcracker Esophagus

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Natural Mg silicates with different structures and morphologies: Reaction with K to produce K2MgSiO4 catalyst for biodiesel production

Surgical Science（外科学） 2024年第1期

作者： Augusto Tinoco Gilberto carvalho Leonardo Tinoco ana Paula Quintão

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International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 46-54页

作者： Fabiane carvalho Ballotin Mayra Nascimento Sara Silveira Vieira Alexandre carvalho Bertoli Ottávio Carmignano ana Paula de carvalho Teixeira Rochel Montero Lago Departamento de Química Universidade Federal de Minas GeraisBelo HorizonteBrasil Doutorado Inovação/Mineradora Pedras Congonhas Universidade Federal de Minas Gerais31270-901 Belo Horizonte-MGBrazil

In this work, different magnesium silicate mineral samples based on antigorite, lizardite, chrysotile(which have the same general formula Mg3Si2O5(OH)4), and talc(Mg3Si4O10(OH)2) were reacted with KOH to prepare catalysts for biodiesel production. Simple impregnation with 20 wt% K and treatment at 700–900°C led to a solid-state reaction to mainly form the K2MgSiO4 phase in all samples. These results indicate that the K ion can diffuse into the different Mg silicate structures and textures, likely through intercalation in the interlayer space of the different mineral samples followed by dehydroxylation and K2MgSiO4 formation. All the materials showed catalytic activity for the transesterification of soybean oil(1:6 of oil : methanol molar ratio, 5 wt% of catalyst, 60°C). However, the best results were obtained for the antigorite and chrysotile precursors, which are discussed in terms of mineral structure and the more efficient formation of the active phase K2MgSiO4.

关键词： silicate serpentinite lizardite antigorite talc chrysotile biodiesel

Thermal and Mechanical Properties of Thermoplastic Starch and Poly(Vinyl Alcohol-Co-Ethylene)Blends

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Journal of Renewable Materials 2019年第3期7卷 245-252页

作者： ana clara Lancarovici Alves Rafael Grande Antonio José Felix carvalho Department of Materials Engineering Sao Carlos School of EngineeringUniversity of Sao PauloAv.Joao Dagnone110013563-120Sao Carlos-SP-Brazil

The interest in thermoplastic starch(TPS)as a substitute material to replace conventional thermoplastics continues especially due its biodegradability,availability,low cost and because it is obtained from renewable ***,its poor mechanical properties and its high sensitivity to humidity have limited its use in several ***,the copolymer poly(ethylene-co-vinyl alcohol)(EVOH),with two different ethylene contents,27 and 44 mol%were blended with TPS by extrusion in order to overcome these *** obtained blends were characterized by thermogravimetric analysis(TGA),differential scanning calorimetry(DSC),mechanical tensile testing,Scanning Electron Microscopy(SEM)and moisture absorption *** addition of EVOH copolymer did not significantly changed the thermal stability of TPS,however it increased the tensile strength in 65%when compared to *** morphology of the blends did not showed two distinct phases,an indication of miscibility or partial miscibility of the components.A decrease of moisture absorption was obtained by the addition of EVOH and is more pronounced for the EVOH with 44% of ethylene.

关键词： Thermoplastic starch EVOH polymer blends thermal properties of polymers mechanical properties of polymers

Degradation of duloxetine: Identification of transformation products by UHPLC-ESI(+)-HRMS/MS,in silico toxicity and wastewater analysis

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Journal of Environmental Sciences 2019年第8期31卷 113-123页

作者： Rodrigo A.Osawa ana P.carvalho Olinda C.Monteiro M.Conceicao Oliveira M.Helena Florêncio Centro de Química e Bioquímica Faculdade de Ciências Universidade de Lisboa Laboratório de FTICR e Espectrometria de Massa Estrutural Faculdade de Ciências Universidade de Lisboa Centro de Química Estrutural Instituto Superior Técnico Universidade de Lisboa

Duloxetine(DUL), an antidepressant drug, has been detected in surface water and wastewater effluents, however, there is little information on the formation of its transformation products(TPs). In this work, hydrolysis, photodegradation(UV irradiation) and chlorination experiments were performed on spiked distillated water, under controlled experimental conditions to simulate abiotic processes that can occur in the environment and wastewater treatment plants(WWTPs). Eleven TPs, nine from reaction with UV light and two from chlorine contact, were formed and detected by ultra-high performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry, and nine of them had their chemical structures elucidated upon analyses of their fragmentation patterns in MS/MS spectra. The formation and degradation of the TPs were observed. The parent compound was completely degraded after30 min in photodegradation and after 24 hr in chlorination. Almost all TPs were completely degraded in the experiments. The ecotoxicity and mutagenicity of the TPs were predicted based on several in silico models and it was found that a few of these products presented more ecotoxicity than DUL itself and six TPs showed positive mutagenicity. Finally, wastewater samples were analyzed and DUL and one TP, possibly formed by chlorination process, were detected in the effluent, which showed that WWTP not only did not remove DUL, but also formed a TP.

关键词： High resolution mass spectrometry Duloxetine Degradation processes Transformation products Wastewater analysis In silico toxicity

Selective silencing of 2Cys and type-ⅡB Peroxiredoxins discloses their roles in cell redox state and stress signaling

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Journal of Integrative Plant Biology 2015年第6期57卷 591-601页

作者： Patrícia Vidigal ana Montserrat Martin-Hernandez Cèlia Guiu-Aragonés Sara Amncio Luísa carvalho Departamento de Recursos Naturais Ambiente e Território (DRAT)/Centro de Botanica Aplicada à Agricultura (CBAA)Institute of AgronomyUniversity of Lisbon Institut de Recercai Tecnologia Agroalimentàries (IRTA) Centre for Research in Agricultural Genomics (CSIC-IRTA-UAB-UB) Campus Universitat Autonoma de Barcelona (UAB)Edificio Center for Research in Agricultural Genomics (CRAG)

Peroxiredoxins （Prx） catalyse the reduction of hydrogen peroxide （H2O2） and, in association with catalases and other peroxidases, may participate in signal transduction by regulating intercel ular H2O2 concentration that in turn can control gene transcription and cel signaling. Using virus-induced-gene-silencing （VIGS）, 2-Cys Peroxiredoxin （2CysPrx） family and type-II Peroxiredoxin B （PrxI B） gene were silenced in Nicotiana benthamiana, to study the impact that the loss of function of each Prx would have in the antioxidant system under control （22℃） and severe heat stress conditions （48 ℃）. The results showed that both Prxs, although in different organel es, influence the regeneration of ascorbate to a significant extent, but with different purposes. 2CysPrx affects abscisic acid （ABA） biosynthesis through ascorbate, while PrxIIB does it probably;through the xanthophyl cycle. Moreover, 2CysPrx is key in H2O2 scavenging and in consequence in the regulation of ABA signal-ing downstream of reactive oxygen species and PrxIIB provides an important assistance for H2O2 peroxisome scavenges.

关键词： 2-Cys Peroxiredoxin abscisic acid ascorbate heat stress hydrogen peroxide peroxisome type-Ⅱ Peroxiredoxin B

Management of hepatitis C in patients with chronic kidney disease

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World Journal of Gastroenterology 2015年第2期21卷 408-422页

作者： Roberto J carvalho-Filho ana Cristina CA Feldner Antonio Eduardo B Silva Maria Lucia G Ferraz Division of Gastroenterology Hepatology SectionFederal University of Sao PauloSao PauloSP 04023-900Brazil

Hepatitis C virus(HCV) infection is highly prevalent among chronic kidney disease(CKD) subjects under hemodialysis and in kidney transplantation(KT) recipients, being an important cause of morbidity and mortality in these patients. The vast majority of HCV chronic infections in the hemodialysis setting are currently attributable to nosocomial transmission. Acute and chronic hepatitis C exhibits distinct clinical and laboratorial features, which can impact on managementand treatment decisions. In hemodialysis subjects, acute infections are usually asymptomatic and anicteric; since spontaneous viral clearance is very uncommon in this context, acute infections should be treated as soon as possible. In KT recipients, the occurrence of acute hepatitis C can have a more severe course, with a rapid progression of liver fibrosis. In these patients, it is recommended to use pegylated interferon(PEG-IFN) in combination with ribavirin, with doses adjusted according to estimated glomerular filtration rate. There is no evidence suggesting that chronic hepatitis C exhibits a more aggressive course in CKD subjects under conservative management. In these subjects, indication of treatment with PEG-IFN plus ribavirin relies on the CKD stage, rate of progression of renal dysfunction and the possibility of a preemptive transplant. HCV infection has been associated with both liver disease-related deaths and cardiovascular mortality in hemodialysis patients. Among those individuals, low HCV viral loads and the phenomenon of intermittent HCV viremia are often observed, and sequential HCV RNA monitoring is needed. Despite the poor tolerability and suboptimal efficacy of antiviral therapy in CKD patients, many patients can achieve sustained virological response, which improve patient and graft outcomes. Hepatitis C eradication before KT theoretically improves survival and reduces the occurrence of chronic graft nephropathy, de novo glomerulonephritis and post-transplant diabetes mellitus.

关键词： Hepatitis C virus Chronic kidney disease End-stage

Appropriateness of the study of iron deficiency anemia prior to referral for small bowel evaluation at a tertiary center

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World Journal of Gastroenterology 2017年第24期23卷 4444-4453页

作者： Jaime Pereira Rodrigues Rolando Pinho Joana Silva ana Ponte Mafalda Sousa Joao Carlos Silva Joao carvalho Department of Gastroenterology Centro Hospitalar Vila Nova de Gaia/EspinhoRua Conceicao FernandesVila Nova de Gaia

To evaluate the adequacy of the study of iron deficiency anemia (IDA) in real life practice prior to referral to a gastroenterology department for small bowel evaluation. METHODSAll consecutive patients referred to a gastroenterology department for small bowel investigation due to iron deficiency anemia, between January 2013 and December 2015 were included. Both patients referred from general practitioners or directly from different hospital departments were selected. Relevant clinical information regarding prior anemia workup was retrospectively collected from medical records. An appropriate pre-referral study was considered the execution of esophagogastroduodenoscopy (EGD) with Helicobacter pylori (H. pylori) investigation, colonoscopy with quality standards (recent, total and with adequate preparation) and celiac disease (CD) screening (through serologic testing and/or histopathological investigation). RESULTSA total of 77 patients (58.4% female, mean age 67.1 ± 16.7 years) were included. Most (53.2%) patients were referred from general practitioners, 41.6% from other hospital specialties and 5.2% directly from the emergency department. The mean pre-referral hemoglobin concentration was 8.8 ± 2.0 g/dL and the majority of anemias had microcytic (71.4%) and hypochromic (72.7%) characteristics. 77.9% of patients presented with an incomplete pre-referral study: EGD in 97.4%, with H. pylori investigation in 58.3%, colonoscopy with quality criteria in 63.6%, and CD screening in 24.7%. Patients with an appropriate study at the time of referral were younger (48.7 ± 17.7 vs 72.3 ± 12.3 years, P < 0.001). Small bowel evaluation was ultimately undertaken in 72.7% of patients, with a more frequent evaluation in patients with a quality colonoscopy at referral (78.6% vs 23.8%); P < 0.001 (OR = 11.7, 95%CI: 3.6-38.6). The most common diagnosis regarded as the likely cause of IDA was small bowel angioectasia (18.2%) but additional causes were also found in the upper and lower ga

关键词： Iron deficiency anemia Colonoscopy Celiac disease Esophagogastroduodenoscopy Helicobacter pylori Small bowel