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Rheological and stability analysis of cement pastes incorporating silica-based wastes

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Particuology 2024年第6期89卷 144-152页

作者： Julia da Rosa martins Janaíde Cavalcante Rocha Dachamir Hotza Luciano Senff Graduate Program in Materials Science and engineering(PPGMAT) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Graduate Program in Civil engineering(PPGeC) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Graduate Program in Chemical engineering(POSeNQ) Federal University of Santa Catarina(UFSC)Florianópolis88040-900SCBrazil Department of Mobility engineering Federal University of Santa Catarina(UFSC)Joinville89219-600SCBrazil

This study investigates the influence of waste characteristics,especially zeta potential,on the properties of cement pastes and *** focus is to evaluate the impact of the zeta potential of cement particles and waste materials on the sedimentation speed,rheology,and hardening time of stabilized cement *** Cement II F 40,retarder additive,silica,and fly ash were used in the *** pastes were prepared,and during the stabilization period,their rheological properties and pH were *** zeta potential and sedimentation speed of the cement and waste particles were measured at the pH that the pastes presented during the entire stabilization *** the stabilization period,the pastes were subjected to the hardening time *** zeta potential analyses revealed diverse values for the different powder types,with the cement particles exhibiting a zeta potential of−3.0 mV,the silica particles exhibiting−10.5 mV,and the fly ash particles exhibiting−20.3 *** influence of the high zeta potential modulus was observed on the sedimentation speed,with the solution containing fly ash exhibiting a speed of 40.01μm/s,whereas the solution containing only cement exhibited a speed of 99.38μm/*** the pastes,the results indicate that the presence of fly ash particles with a significantly negative zeta potential led to a 16%reduction in hardening time compared to particles with a lower modulus of zeta *** tests showed that the inclusion of fly ash particles prevented the formation of *** the zeta potential influenced agglomerate formation and hardening time,it was found to have no effect on yield stress or viscosity.

关键词： Wastes Zeta potential Setting time Rheometry

A new approach to pedestal differentiation for soil loss estimation-a case study from a burnt area in north-central Portugal

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Journal of Forestry Research 2024年第3期35卷 45-54页

作者： Frank G.A.Verheijen Martinho A.S.martins Sergio A.Prats Jan J.Keizer Centre for environmental and Marine Studies(CeSAM) Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal Mediterranean Institute for Agriculture Environment and Development(MED-CHANGE)Institute for Advanced Studies and ResearchUniversity of EvoraPolo da MitraAp.947006-554 EvoraPortugal GeoBiociencias Geotecnologias E Geoengenharias(GEOBIOTEC)Department Environment and PlanningUniversity of Aveiro3810-193 AveiroPortugal

Soil pedestals have long been used as qualitative indicators of soil splash *** rangelands,plant-capped pedestals,generally grass tussocks,have also been used to quantitatively estimate soil loss since the first half of the twentieth *** agricultural lands,forests,and bad-lands,stone-capped pedestals have been used as qualitative and semi-quantitative indicators of active,'extreme'*** work has been reported on using capstone pedestal data for quantifying soil *** postulate that three distinct capstone pedestal types may be present in any given location and that a detailed analysis of a pedestal height histogram may be used to recognize their *** analysis can subsequently inform if soil loss can be reliably estimated and if so,which of the existing methods using pedestal height data will provide more accurate *** three proposed capstone pedestal types are:(1)neo-pedestals formed underneath surface stones exposed by(partial)removal of the soil surface cover;(2)endo-pedestals formed underneath stones that were buried in the soil but have been exposed by erosion;and(3)phoenix-pedestals formed underneath stones from collapsed *** the pedestal height histogram of any given location,a skew to smaller heights may indicate the existence of endo-and/or phoenix-pedestals,which may be revealed as a bi-(or tri)modal distribution when using a smaller bin *** concept was applied to a case study where soil loss had been monitored for control plots and mulched plots during a 5-year period following wildfire in a eucalypt *** measured pedestal heights and used methods to quantitatively assess soil loss from soil pedestal data in the available *** pedestal data at the end of the 5-year period under or overestimated soil loss in the control treatment,with results ranging from 60 to 115%of measured soil loss,depending on the *** is postulated that phoenix-and endo-pedestals may be a driving fact

关键词： Soil pedestals Mulch Wildfire Soil erosion Char

Columnar joints in the Patino Formation sandstones, eastern Paraguay： a dynamic interaction between dyke intrusion, quartz dissolution and cooling-induced fractures

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episodes 2008年第3期31卷 302-308页

作者： Victor Fernandez Velazquez Paulo Cesar Fonseca Giannini Claudio Riccomini alethea ernandes martins sallun Jorge Hachiro Celso de Barros Gomes eseola de Artes Ciencias e Humanidades Universidade de Sao Paulo Rua Arlindo Betio 1000 03828-080 Sao Paulo Brasil Instituto de Geociencias Universidade de Sao Paulo Rua do Lago 562 05508-080 Sao Paulo Brasil Insfituto Geolegico Secretaria do Meio Ambiente Av. Miguel Estefano 3900 04301-903 Sao Paulo Brasil.

The Patiho Formation sandstones, which crop out in Aregud neighborhood in eastern Paraguay and show columnar joints near the contact zone with a nephelinite dyke, have as their main characteristics the high pro- portion of syntaxial quartz overgrowth and a porosity originated from different processes, initially by dissolu- tion and later by partial filling and fracturing. Features like the presence of floating grains in the syntaxial cement, the transitional interpenetrative contact between the silica-rich cement and grains as well as the intense fracture porosity are strong indications that the cement has been formed by dissolution and reprecipita- tion of quartz from the framework under the effect of thermal expansion followed by rapid contraction. The increase of the silica-rich cement towards the dyke in association with the orthogonal disposition of the columns relative to dyke walls are indicative that the igneous body may represent the main heat source for the interstitial aqueous solutions previously existing in the sediments. At macroscopic scale, the increasing of inter- nal tensions in the sandstones is responsible for the nucleation of polygons, leading to the individualization of prisms, which are interconnected by a system of joints, formed firstly on isotherm surfaces of low tem- perature and later on successive adjacent planes towards the dyke heat source.

关键词：柱状连接砂岩巴拉圭南美洲动力学

A single session of strength training changed plasma levels of resistin,but not leptin in overweight and obese men

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Sports Medicine and Health Science 2024年第4期6卷 324-330页

作者： Yago martins Fortes Antonio Felipe Souza-Gomes Alessandro Roberto Silveira Moreira Leo Nogueira Campos Samara Silva de Moura Lucelia Scarabeli Silva Barroso Marcelo Henrique Salviano de Faria Heliana de Barros Fernandes Aline Silva de Miranda Hugo Cesar martins-Costa Ana Cristina Simoes e Silva Janaina Matos Moreira Albena Nunes-Silva Laboratory of Inflammation and exercise Immunology Department of Physical EducationSchool of Physical EducationFederal University of Ouro PretoOuro PretoMGBrazil Postgraduate Program in Health and Nutrition Nutrition SchoolFederal University of Ouro PretoOuro PretoMGBrazil Interdisciplinary Medical Research Laboratory Faculty of MedicineFederal University of Minas GeraisBelo HorizonteMGBrazil Neurobiology Laboratory Institute of Biological SciencesFederal University of Minas GeraisBelo HorizonteMGBrazil Department of Physical education Pontifical Catholic University of Minas GeraisBrazil Department of Pediatrics Faculty of MedicineFederal University of Minas Gerais(UFMG)Belo HorizonteMGBrazil

Obesity has a complex multifactorial etiology and is characterized by excessive accumulation of adipose *** adipose tissue has deleterious effects on health because it secretes large amounts of inflammatory *** calorie restriction associated with strength training may be useful in managing chronic systemic *** study aimed to evaluate the acute effect of a single strength-training session on plasma adipokine levels in sedentary,overweight,and obese young *** study included twelve men(Age:[34.95±9.77]years;Height:[174.16±3.66]centimeter[cm];Weight:[97.83±12.87]kilogram(kg);body mass index[BMI]:[32.30±4.51]kg/m2),who performed a single strength training *** strength training protocol consisted of 4 sets of 12 repetitions in the following six exercises,45°leg press,bench press,leg extension,machine row,leg curl,and shoulder *** samples were collected before,immediately after,and 1-h subsequent after strength *** plasma levels of resistin and leptin were measured.A significant decrease in resistin levels were found 1 h after the strength training session if compared to levels before the training session(pre-[before][2390±1199]picograms per milliliter[pg/mL]vs post-1 h[1-h subsequent][1523±798],6 pg/mL,p=0.0028).The plasma leptin levels did not differ at any time *** conclusion,a very well controlled single session of strength training significantly decreased the plasma levels of resistin without altering the concentration of leptin in overweight and obese *** effect,at least in part,supports the benefits of exercise by reducing the low grade inflammation and insulin resistance in obesity.

关键词： Strength training Adipose tissue Obesity Chronicinflammation Resistin Leptin

Combined grafts and flaps in urethral stricture repair

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Plastic and Aesthetic Research 2022年第1期9卷 213-224页

作者： Francisco Dávila Tiago Rosito Borko Stojanovic Francisco e.martins Department of Urology Hospital de Clínicas de Porto AlegreUFRGSPorto Alegre 90035-903Brazil Department of Urology Belgrade Center for Urogenital Reconstructive SurgerySchool of MedicineUniversity of BelgradeBelgrade 11000Serbia Department of Urology School of MedicineUniversity of LisbonCHULNLisbon 1649-028Portugal

Although urethral strictures have been known since antiquity,the surgical management of urethral strictures has undergone a great(re)evolution over the last six decades,both in the perception of the disease and in the surgical repair techniques,always presenting itself as a challenge for the surgeon and *** of urethral stricture disease involving a combination of grafts and flaps consists of a group of complex procedures with specific clinical *** knowledge of these procedures by reconstructive urologists is both necessary and relevant.A thorough understanding of the anatomy,including blood supply,is a crucial proviso for the correct evaluation and successful management of urethral stricture *** discuss the main techniques and indications in combined graft and flap urethroplasties.

关键词： Urethral stricture urethral stenosis genital flap penile flap reconstructive urology combined urethral surgery

Quaternary： “Quo Vadis”？

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episodes 2005年第3期28卷 197-200页

作者： Kenitiro Suguio Alethéea ernandes martins sallun emilio A. A. Soares Centro de Pós-Graduacāo Pesquisa e Extensāo （CEPPE） Universidade Guarulhos （UnG） Praca Tereza Cristina 01-Guarulhos-SP-Brazil-07023-070 Programa de Pós-Graduacāo em Geologia Sedimentar-Instituto de Geociencias Universidade de Sāo Paulo Rua do Lago 562-Sāo Paulo-SP-Brazil-05508-080 Departamento de Geociencias Universidade Federal do Amazonas Av. Gal. Rodrigo O.J. Ramos 3000 Manaus-AM-Brazil-69077-000

The Quaternary, like the long-abandoned terms Primary, Secondary and Tertiary, is a very ambiguous word, whose chronological meaning is not very well defined. Its usage spread very quickly, perhaps due to its more-or-less close relationship with the human history and with the latest glaciations. However, the oldest of human fossil record, according to recent discoveries in Africa （Djourab Desert in Tchad）, is about 7 million years old, rather than 2 million years as suggested by fossils at OlduvaL Moreover, for some time now, it has been known that the first Quaternary-type glaciations occurred in several regions of the earth between 2.5 and 3 million years ago, that is prior to the Pliocene-Pleistocene limit at 1.81 million years ago, as determined by the GSSP. These facts have led some researchers, mostly from the International Union of Geological Sciences （lUGS）, and from the International Association for Quaternary Research （INQUA）, to suggest changes in the subdivision of the Neocenozoic. Certainly, discussions on this subject will be raised at many scientific meetings in the near future until almost unanimous agreement can be attained. Some additional suggestions are presented here, as a contribution to resolution of these nomenclatorial issues.

关键词：冰河作用化石非洲更新世上新世冰川

Antioxidants enzymes Activities and NO Levels in Hemodialysis and Continuous Ambulatory Peritoneal Dialysis—A Comparative Study

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Journal of Biosciences and Medicines 2024年第2期12卷 50-59页

作者： Natalia Cristina Aparecida Ribeiro e Ribeiro Anderson martins Tavares Jaslana Hainfellner da Silva João Paulo Lima Daher Salim Kanaan Luciene de Carvalho Cardoso-Weide Laboratory of Neuroplasticity Neurobiology Department Biology Institute Federal Fluminense University Rio de Janeiro Brazil Postgraduate Program in Medical Sciences School of Medicine Federal Fluminense University Rio de Janeiro Brazil School of Biology UNIVERSO—Salgado de Oliveira University Rio de Janeiro Brazil Department of Pathology Faculty of Medicine Federal Fluminense University Rio de Janeiro Brazil

It consists of a retrospective study with twenty-two individuals diagnosed with DRC: fourteen HD and eight CAPD, followed up in the dialysis center of Antonio Pedro University Hospital (HUAP) of Fluminense Federal University (UFF), between 2015 and 2017. Fifteen healthy control (HC) subjects were included, without diagnosed CKD. Patients with HIV positive, hepatitis A, B, and C, pregnant, cancer, smokers, alcoholics and those exposed to X-rays in the last 3 months, were excluded. Objectives: As oxidative stress and endothelial dysfunction may be linked to the higher prevalence of CVD in CKD patients, we measured the activities of the antioxidants enzymes: SOD and GPx and total NO levels in the plasma and serum of end-stage CKD patients undergoing dialysis therapy, comparing with the HC group. Methods: Quantification of NO levels was performed by fluorometric kit, while activities of SOD and GPx were determined using kinetic methods. Results: We found higher plasma SOD activity in HD (8.58 U/ml) and CAPD (10.14 U/ml), compared to C (3.73 U/ml) group, while GPx activity was decreased in HD (115.38 nmol/h/ml) and CAPD (122.76 nmol/h/ml) groups compared to HC group (275.83 nmol/h/ml). Total serum NO concentration was decreased in HD (14.09 pmol/μl) and CAPD (10.26 pmol/μl), compared to non-CKD patients (49.65 pmol/μl). Conclusion: Decreased total serum NO and GPx activities may lead to endothelial dysfunction and consequently a higher prevalence of CVD in CKD patients.

关键词： Hemodialysis CAPD SOD GPx NO

Impact Containment Barriers with Geotextile Tubes

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Journal of Geoscience and environment Protection 2024年第5期12卷 325-344页

作者： Flávio da Silva Ornelas Luís Fernando martins Ribeiro Rafael Cerqueira Silva Instituto Federal de educaç &#227o Ci&#234ncia e Tecnologia&#8212IFTO Palmas Brasil Departamento de engenharia Civil e Ambiental Programa de p&#243s gradua&#231&#227o em Geotecnia Universidade de Bras&#237lia&#8212UnB/Campus Universit&#225rio Darcy Ribeiro Bras&#237lia Brasil

Recently, tragic tailings dam collapses in Brazil have caused deaths and major destruction and the need to develop technologies capable of preventing damage to people and the environment. Brazilian tailings dams are in a situation of uncertainty due to new legislation that even requires decommissioning, an activity that involves many problems and where the risk of failure is the main one. An impact containment structure downstream of these dams can be effective and geotextile tubes, in a new approach, have emerged as an option with advantages in terms of execution, costs and safety. The technology is versatile and can bring many benefits such as the reuse of tailings or filling with low-energy or reused materials. In this research, geotextile tubes were tested as free containment barriers, experiencing impacts in reduced models. The safety factor for the stability of the structure was constructed using an equation which is the ratio between the self-weight of the barrier structure and its coefficient of static friction and the impact pressure, where the data showed an adequate correlation which suggests the viability of mitigating risks.

关键词： Geotextile Tube Debris Flow Barriers Impact Mining

An oxygenating colloidal bioink for the engineering of biomimetic tissue constructs

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Bio-Design and Manufacturing 2024年第3期7卷 240-261页

作者： Seol-Ha Jeong Jarno Hiemstra Patrick V.Blokzijl Rebeca Damian-Ferrara Danilo martins dos Santos Jéssica H.L.da Fonseca Min-Ho Kang Jihyun Kim Dilara Yilmaz-Aykut Mei L.L.Cham-Pérez Jeroen Leijten Su Ryon Shin Division of engineering in Medicine Department of MedicineBrigham and Women’s HospitalHarvard Medical SchoolBostonMA 02139USA Leijten Lab Department of Developmental BioEngineeringFaculty of Science and TechnologyTechnical Medical CentreUniversity of TwenteDrienerlolaan 57522 NB EnschedeThe Netherlands Nanotechnology National Laboratory for Agriculture(LNNA) Embrapa InstrumentaçãoSao CarlosSao Paulo 13560-970Brazil Department of Biomedical-Chemical engineering The Catholic University of Korea43 Jibong-roBucheon-siGyeonggi-do 14662Republic of Korea Department of Biotechnology The Catholic University of Korea43 Jibong-roBucheon-siGyeonggi-do 14662Republic of Korea

ensuring a sufficient oxygen supply is pivotal for the success of bioprinting applications since it fosters tissue integration and natural *** in oxygen concentration among diverse tissues necessitates the precise recreation of tissue-specific oxygen levels in imprinted constructs to support the survival of targeted *** oxygen-releasing biomaterials,such as oxygen-generating microparticles(OMPs),have shown promise for enhancing the oxygen supply of microenvironments in injured tissues,whether this approach is scalable for large tissues and whether tissue-specific bioinks with varying OMP concentrations remain printable remain *** study addresses this critical gap by introducing an innovative class of engineered oxygenated bioinks that combine colloidal-based microgels with *** report that incorporating nanosized calcium peroxide(nCaO_(2))and manganese oxide nanosheets(nMnO_(2))into hydrophobic polymeric microparticles enables precise modulation of oxygen release while controlling hydrogen peroxide ***,the fabrication of oxygenating and cytocompatible colloidal gels is achieved using an aqueous two-phase *** study thoroughly evaluates the fundamental characteristics of the resulting bioink,including its rheological behaviors,printability,shape fidelity,mechanical properties,and oxygen release ***,this study demonstrates the macroscopic scalability and cytocompatibility of printed constructs produced via cell-laden oxygenating colloidal *** showcasing the effectiveness of extrusion-based bioprinting,this study underscores how it can be used to fabricate biomimetic tissues,indicating its potential for new *** findings presented here advance the bioprinting field by achieving scalability with both high cell viability and the possibility of mimicking specifically oxygenated *** work thereby offers a promising avenue for the development of functional tissues with e

关键词： 3D bioprinting Bioink Colloidal gels extrusion printing Oxygen-generating microparticle