ABSTRACT Objective : To evaluate the remineralizing effect of synthetic saliva on eroded bovine dental enamel. Materials and methods : 50 enamel blocks were prepared from bovine teeth. The specimens were divided into 5 study groups according to treatment: group A (Colgate Total®, toothpaste containing fluoride), group B (MI Paste Plus®, toothpaste containing casein phosphopeptide, amorphous calcium phosphate [CPP-ACP] with fluoride), group C (Salival® Solution, synthetic saliva), group D (distilled water) and group E (no treatment). All specimens in groups A, B, C and D received 0.5% citric acid attacks for 2 minutes at 0, 8, 24 and 32 hours. After each acid attack, toothpastes corresponding to each treatment group were applied. The degree of mineralization was then evaluated by Raman microscopy and surface microhardness by Vickers microhardness. Results : Regarding the degree of mineralization and surface hardness, no significant differences (p > 0.05) were found in the eroded bovine tooth enamel treated with Colgate Total®, Mi Paste Plus® and Salival® Solution in comparison with the healthy enamel samples. But all presented a significantly higher degree of mineralization and surface hardness than the eroded bovine tooth enamel samples preserved in distilled water (p < 0.05). Conclusion : This in vitro study shows that the synthetic saliva Salival® Solution has a remineralizing potential on eroded bovine enamel.

RESUMEN Objetivo : Evaluar el efecto remineralizante de una saliva sintética en el esmalte dental bovino erosionado. Materiales y métodos : Se prepararon 50 bloques de esmalte de dientes de bovino. Las muestras fueron divididas en 5 grupos de estudio según el tratamiento: grupo A (Colgate Total®, pasta de dientes que contiene fluoruro), grupo B (MI Paste Plus®, pasta de dientes que contiene fosfopéptido de caseína-fosfato de calcio amorfo [CPP-ACP] con fluoruro), grupo C (Salival® Solución, saliva sintética), grupo D (agua destilada) y grupo E (sin tratamiento). Todos los especímenes de los grupos A, B, C y D recibieron ataques con ácido cítrico al 0,5 % durante 2 minutos a las 0, 8, 24 y 32 horas. Después de cada ataque ácido, se aplicaron las pastas de dientes correspondientes a cada grupo de tratamiento. Luego se procedió a evaluar el grado de mineralización mediante microscopía Raman y la microdureza superficial mediante microdureza Vickers. Resultados : Respecto al grado de mineralización y la dureza superficial, no se encontraron diferencias significativas (p > 0,05) en el esmalte dental bovino erosionado tratado con Colgate Total®, MI Paste Plus® y Salival® Solución en comparación con las muestras de esmalte sano; sin embargo, todas presentaron un grado de mineralización y dureza superficial significativamente mayor que las muestras de esmalte de dientes bovinos erosionados conservados en agua destilada (p < 0,05). Conclusión : Este estudio in vitro muestra que la saliva sintética Salival® Solución tiene un potencial remineralizante en el esmalte bovino erosionado.

RESUMO Objetivo : Avaliar o efeito remineralizante de uma saliva sintética no esmalte dentário bovino erodido. Materiais e métodos : Foram preparados 50 blocos de esmalte de dentes de bovinos. As amostras foram divididas em 5 grupos de estudo de acordo com o tratamento: grupo A (Colgate Total®, pasta dentífrica contendo flúor), grupo B (MI Paste Plus®, pasta dentífrica contendo fosfopeptídeo de caseína, fosfato de cálcio amorfo [CPP-ACP] com flúor), grupo C (Salival® Solution, saliva sintética), grupo D (água destilada) e grupo E (sem tratamento). Todos os espécimes dos grupos A, B, C e D receberam um ataque ácido cítrico a 0,5% durante 2 minutos às 0, 8, 24 e 32 horas. Após cada ataque ácido, foram aplicadas as pastas dentífricas correspondentes a cada grupo de tratamento. O grau de mineralização foi então avaliado por microscopia Raman e a microdureza superficial por microdureza Vickers. Resultados : Relativamente ao grau de mineralização e à dureza da superfície, não foram encontradas diferenças significativas (p > 0,05) no esmalte dentário bovino erodido tratado com Colgate Total®, Mi Paste Plus® e Salival® Solution em comparação com as amostras de esmalte saudável. Mas todos mostraram um grau significativamente mais elevado de mineralização e dureza superficial do que as amostras de esmalte de dentes de bovinos erodidos preservados em água destilada (p < 0,05). Conclusão : Este estudo in vitro mostra que a saliva sintética Salival® Solution tem um potencial remineralizante no esmalte bovino erodido.

ABSTRACT Autoclaved Aerated Concrete (AAC) developed with Coconut Shell Charcoal (CSC) powder is a newly developed concrete with reasonable compressive strength and durability properties. The main idea of this study is to find out the applicability of CSC powder as partial replacement for fine aggregate in AAC, and the role of CSC in obtaining the strength and durability of AAC are discussed. In this study, material selection is done with reference to ASTM C1693-11 and CSC was used as a replacement material for river sand. CSC is an agricultural waste. Since the SiO2 content of CSC is very low, Silica Fume (SF) is also used as fine aggregate replacement in addition to CSC to enhance the SiO2 content. The specimens were made combining CSC and SF powders; CSC at 0%, 5%, 10%, 15% and 20% and SF at 0%, 1%, 2%, 3% and 4% by weight, and are coded as B0, B5, B10, B15 and B20 respectively. The developed AAC was analysed by conducting compressive strength, bulk density, thermal conductivity, scanning electron microscope (SEM) and X-ray diffraction (XRD) analyses. Additionally, water absorption, porosity, ultrasonic pulse velocity and acid attack tests were performed to determine the durability. XRD analysis showed the traces of C-S-H (Calcium Silicate Hydrate) gel and tobermorite peaks in B5 specimen, which produced enhanced compressive strength of 3.12 N/mm2. Thermal conductivity of the specimen with CSC replacement was between 0.218 to 0.186 W/m-K; it could be remarked from the results that the developed AAC is good in thermal insulation. Even though the porosity level reduced to 2% in B20 replacement, the specimens were light in weight, compared to B0. From the results obtained, it could be drawn the inference that CSC is a potential replacement for fine aggregate in AAC. (AAC (CSC properties discussed C169311 C C1693 11 C1693-1 sand waste SiO low (SF powders 0 0% 5 5% 10 10% 15 20 1 1% 2 3 4 weight B0 B B10 B1 B2 respectively density SEM (SEM Xray X ray (XRD analyses Additionally absorption CSH S H Calcium Hydrate 312 12 3.1 Nmm2 Nmm N mm2 mm N/mm2 0218 218 0.21 0186 186 0.18 W/mK WmK W/m K W m W/m-K insulation obtained C16931 C169 C1693- 31 3. N/mm 021 21 0.2 018 18 0.1 mK Wm C16 02 0. 01 C1

Abstract Migraine is one of the most prevalent and disabling diseases in the world. Migraine attack treatments and prophylactic treatments of this disease are essential to lessen its individual, social, and economic impact. This is a narrative review of the main drugs used for treating migraine, as well as the experimental models and the theoretical frameworks that led to their development. Ergot derivatives, triptans, non-steroid anti-inflammatory drugs, tricyclic antidepressants, beta-blockers, flunarizine, valproic acid, topiramate, onabotulinumtoxin A, ditans, monoclonal antibodies against CGRP and its receptor, and gepants are discussed. Possible therapeutic targets for the development of new drugs that are under development are also addressed. Many of the drugs currently in use for treating migraine were developed for the treatment of other diseases, but have proven effective for the treatment of migraine, expanding knowledge about the disease. With a better understanding of the pathophysiology of migraine, new drugs have been and continue to be developed specifically for the treatment of this disease. world individual social impact derivatives triptans nonsteroid non steroid antiinflammatory anti inflammatory antidepressants betablockers, betablockers beta blockers, blockers beta-blockers flunarizine acid topiramate A ditans receptor discussed addressed

Resumo A migrânea é uma das doenças mais prevalentes e incapacitantes do mundo. O tratamento da crise de migrânea e o tratamento profilático da doença são essenciais para diminuir o seu impacto individual, social e econômico. Este é um artigo de revisão narrativa. Revisamos as principais drogas usadas para a migrânea e os modelos experimentais e referenciais teóricos que levaram ao seu desenvolvimento. Foram abordados os derivados do ergot, triptanas, anti-inflamatórios não hormonais, antidepressivos tricíclicos, betabloqueadores, flunarizina, ácido valproico, topiramato, toxina onabotulínica do tipo A, os ditans, anticorpos monoclonais contra o CGRP e seu receptor e os gepants. Também foram abordados possíveis alvos terapêuticos para o desenvolvimento de novas drogas e drogas que estão em desenvolvimento para o tratamento da migrânea. Muitas das drogas usadas atualmente foram desenvolvidas para o tratamento de outras doenças e se mostraram efetivas para o tratamento da migrânea. Essas ajudaram a ampliar o conhecimento sobre a doença. Com o melhor entendimento da fisiopatologia da migrânea, novas drogas foram e estão sendo desenvolvidas especificamente para o tratamento dessa doença. mundo individual econômico narrativa ergot triptanas antiinflamatórios anti inflamatórios hormonais tricíclicos betabloqueadores flunarizina valproico topiramato ditans gepants

Increasingly high levels of multidrug-resistant (MDR) pathogens have necessitated the discovery of novel bioactive compounds. For this reason, two actinomycetes strains, Streptomyces griseorubens and Streptomyces rochei, were isolated for the first time from the black sand shores of Kafr El Sheikh in Egypt, which is home to several large fish farms. Isolates were identified via phenotypic, biochemical and 16S rRNA sequence protocols. Both strains exhibited powerful antimicrobial activity against three serious MDR pathogens: Bacillus subtilis, Salmonella enteritidis and Pseudomonas aeruginosa. The bioactive compounds of isolates' filtrates were identified using gas chromatography-mass spectroscopy (GC-MS). For S. griseorubens, the detectable antibacterial compounds were hexanoic acid, 2-ethyl-, 2-ethylhexyl ester, n-Decane, hexadecanoic acid methyl ester, benzene acetic acid, ricinolic acid, and ethylparaben, while S. rochei secretes heptadecane, 2,6-dimethyl-, benzene acetic acid, dibutyl phthalate, octacosane, hexacosane, and vitamin A aldehyde. These results strongly encourage the use of these eco-friendly isolates as a biocontrol against MDR pathogens that attack fish farms. SIGNIFICANCE: Streptomyces spp. act as strong weapons for fighting multidrug resistance in pathogenic bacteria - one of the most important current threats to public health. They are additionally regarded as eco-friendly organisms that can be used as a biocontrol agent against infections that endanger fish farms

Abstract. In the present research work, the corrosion inhibition capacity of a liquid extract based on Citrus X-Latifolia leaves was evaluated as a green inhibitor that complies with a natural, economical, and environmentally friendly option. The tests were carried out on a carbon steel AISI 1045 exposed to an acid corrosive medium of 10 mL H2SO4 (0.5 M) to which various concentrations of the extract were dosed as follows: 40, 80, 120, 160, 200, 240, 280, 320, 360 and 400 ppm under standard conditions. Characterization by FT-IR was carried out to detect functional groups of the extract. The inhibitory behavior was recorded by electrochemical techniques (Tafel polarization and EIS). Finally, optical microscopy was used to evaluate the corrosion morphology. The results reveal that the adsorption of the extract molecules on steel follows the behavior of a Langmuir isotherm, reaching a maximum efficiency of 89 % with a concentration of 400 ppm. Finally, an evident change in the surface morphology of the steel sample is observed, thus reducing the pitting corrosion attack on AISI 1045 steel.

Resumen. En el presente trabajo de investigación se evaluó la capacidad de inhibición de la corrosión de un extracto líquido a base de hojas de Citrus X-Latifolia como inhibidor verde que cumpla como una opción natural, económica y amigable con el medio ambiente. Los ensayos se realizaron sobre un acero al carbono AISI 1045 expuesto a un medio ácido corrosivo de 10 mL de H2SO4 (0,5 M) al que se dosificaron diversas concentraciones del extracto: 40, 80, 120, 160, 200, 240, 280, 320, 360 y 400 ppm en condiciones estándar. Se realizó una caracterización por FT-IR para detectar los grupos funcionales del extracto. El comportamiento inhibitorio se registró mediante técnicas electroquímicas (polarización de de Tafel y EIS). Finalmente, se utilizó microscopía óptica para evaluar la morfología de la corrosión. Los resultados revelan que la adsorción de las moléculas del extracto sobre el acero sigue el comportamiento de una isoterma de Langmuir, alcanzando una eficiencia máxima del 89 % con una concentración de 400 ppm. Finalmente, se observa un cambio evidente en la morfología superficial de la muestra de acero, reduciéndose así el ataque de corrosión por picaduras en el acero al carbono 1045.

A theoretical investigation of the 1,2-additon and 1,4-addition reactions of benzylamine to crotonaldehyde in toluene solution is reported in this study, including the effect of trace amounts of acetic acid (AcOH) and methanesulfonic acid (CH3SO2OH). We have determined the reaction free energy profile and performed a detailed microkinetic analysis. Our results point out that this reaction system needs catalysis to take place and it was found that CH3SO2OH is a powerful catalyst, outperforming AcOH in lowering the free energy barrier for the 1,2-addition reaction, which leads to the formation of α,β-unsaturated imine. On the other hand, the 1,4-addition reaction has the direct nucleophilic attack of benzylamine to the β-carbon of s-cis conformation of crotonaldehyde as the rate-determining step, corresponding to slow kinetics. Our results suggest that the experimentally observed formation of the imine can be explained by the presence of hidden acid catalysts present in the reaction medium. 1,2additon 12additon additon 1,2 1 2 1,4addition 14addition addition 1,4 4 study (AcOH CH3SO2OH. CHSOOH . CH SO OH (CH3SO2OH) analysis catalyst 1,2addition 12addition α,βunsaturated αβunsaturated α,β unsaturated α β hand βcarbon carbon scis s cis ratedetermining rate determining step kinetics medium 2additon 12 1, 4addition 14 (CH3SO2OH 2addition βunsaturated αβ

Abstract Introduction The importance of roughness for osseointegration is due to the configuration of proteins with the surface of the implant, and adsorption. Different methods are used in surface treatments, in which parts of the surface layer are removed, such as acid attack. Objective To analyze changes in roughness on the surface of osseointegrated implants treated by double acid etching with single-use and up to 4 reuses of serums at a magnification of 500x, 1000x, 2000x, and 4000x in the scanning microscope (SEM). Method Samples of adherent implants (SINGULAR Implants ®) of lever alloy (n=10) were subdivided into 5 groups: control, treatment 1, 2, 3, and 4, according to the reuses. For the surface topography of the samples, SEM was used, followed by analysis by ImageJ software. Using the ANOVA test and Turkeys post-test, Ra and Rq values were statistically analyzed. Result The data obtained both by the images captured in the SEM and by the Ra and Rq numbers acquired by the ImageJ illustrate that the treatment with the double acid attack with 5 uses of the same ones served, was positive for the surface treatment of the alloy implant of independent. Conclusion It can be concluded that up to four reuses of food do not statistically interfere with roughness values. More studies are needed regarding the reuse of acids, certainly to reduce costs to manufacturers, increasing sustainability while maintaining product quality. adsorption treatments removed singleuse single use 500x x 1000x 2000x SEM. . (SEM) SINGULAR ® n=10 n10 n 10 (n=10 groups control 1 2 3 samples software posttest, posttest post test, post-test analyzed served independent acids manufacturers quality (SEM n=1 n1 (n=1 n= (n= (n

Resumo Introdução A importância da rugosidade para a osseointegração se dá pela correlação das interações das proteínas com a superfície do implante, a adsorção. Diferentes métodos são utilizados nos tratamentos de superfície, em que ocorre a remoção de partes da camada superficial, como o ataque ácido. Objetivo Analisar as alterações de rugosidade na superfície dos implantes osseointegrados tratadas por duplo ataque ácido com uso único e até quatro reutilizações dos ácidos. Material e método As amostras de implantes dentários de liga de titânio (SINGULAR Implants ®) (n = 10) foram subdividas em cinco grupos: controle, tratamento 1, 2, 3 e 4, conforme as reutilizações dos ácidos. As capturas dos implantes no aumento de 500x, 1000x, 2000x e 4000x foram realizadas no microscópio eletrônico de varredura, para posterior análise de rugosidade pelo software ImageJ. Os valores de Ra e Rq foram analisados estatisticamente pelo teste ANOVA e o pós-teste de Tukey. Resultado Os dados obtidos pelas imagens capturadas e pelos números de Ra e Rq adquiridos pelo ImageJ demonstraram que o tratamento com o duplo ataque ácido com cinco utilizações dos mesmos ácidos foi positivo para o tratamento de superfície do implante de liga de titânio. Conclusão Pode-se concluir que até quatro reutilizações dos ácidos não interferiu estatisticamente nos valores de rugosidade em diferentes aumentos. São necessários mais estudos referentes à reutilização dos ácidos, contribuindo para a diminuição dos custos aos fabricantes, aumentando a sustentabilidade e mantendo-se a qualidade do produto. adsorção superficial SINGULAR ® n 10 grupos controle 1 2 4 500x x 1000x varredura pósteste pós Tukey Podese Pode aumentos fabricantes mantendose mantendo produto

Abstract Introduction Different methodologies were used for histological evaluation of osseointegration, leading to different results. Objective The objective is to compare different methodologies for histomorphometric analysis of the osseointegration of implants with different surfaces, installed in rat tibias. Material and method Twenty-four rats were randomly divided into 3 groups (n=8) for implant installation. These groups were divided according to the type of implant that will be installed in the tibia: Hydrophilic Group (installation of an implant with a surface modified by oxide blasting and acid attack and maintained in a sodium chloride solution), Hydrophobic Group (installation of an implant with surface modified by oxide blasting and acid attack) and Machined Group (implant installation with machined surface). Within 45 days after the surgical procedures to install the implants, the animals were euthanized and the tibias were removed, and histological processing was carried out for non-decalcified samples. After obtaining the slides, histomorphometric analysis was performed to evaluate the percentages of bone-implant contact (%BIC) and the bone area between the turns (%BBT). Measurements were carried out in two different regions: 1) the implant threads in the cortical bone region and 2) all implant threads inserted into the bone (cortical and medullary). Statistical analysis was performed using One-Way ANOVA followed by Tukey's test for inferential data analysis. Result The BIC and BBT were analyzed independently in the cortical and trabecular/total regions, a difference was observed in the histological behavior of the implants according to the surface treatment. HFL implants showed trabecular BIC (%) 16.85% higher (p=0.02) than HFB implants and 26.12% higher (p≤0.0001) than machined implants. However, the cortical region of all groups showed significantly higher cortical BIC values around the implants, regardless of the surface. Conclusion the results obtained demonstrated that peri-implant bone formation was superior in analyzes carried out only on cortical bone, compared to the values obtained in the total measurement (cortical bone plus medullary bone). It was also possible to observe that, even within the same surface, the BIC(%) values were higher in cortical bone. Within the limitations of the study, it can be concluded that different methodologies for histometric analysis of osseointegration around different surfaces of implants installed in rat tibias can interfere with the results of osseointegration regardless of the surface analyzed. Twentyfour Twenty four n=8 n8 n 8 (n=8 tibia solution, solution , solution) . surface) 4 removed nondecalcified non decalcified samples slides boneimplant %BIC (%BIC %BBT. %BBT (%BBT) regions 1 2 medullary. medullary) OneWay One Way Tukeys Tukey s trabeculartotal treatment % (% 1685 16 85 16.85 p=0.02 p002 p 0 02 (p=0.02 2612 26 12 26.12 p≤0.0001 p00001 0001 (p≤0.0001 However periimplant peri bone) BIC% BIC(% study n= (n= (%BBT ( 168 16.8 p=0.0 p00 (p=0.0 261 26.1 p≤0.000 p0000 000 (p≤0.000 BIC( (n 16. p=0. p0 (p=0. 26. p≤0.00 p000 00 (p≤0.00 p=0 (p=0 p≤0.0 (p≤0.0 p= (p= p≤0. (p≤0. (p p≤0 (p≤0 p≤ (p≤

Resumo Introdução Diferentes metodologias tem sido utilizadas para avaliação histológica da osseointegração, levando a diferentes resultados. Objetivo O objetivo é comparar diferentes metodologias de análise histomorfométrica da osseointegração de implantes com diferentes superfícies, instalados em tíbias de ratos. Material e método 24 ratos foram aleatoriamente divididos em 3 grupos (n = 8) para a instalação dos implantes. Esses grupos foram divididos de acordo com o tipo de implante instalado na tíbia: Grupo Hidrofílico - HFL (instalação de implante com superfície modificada por jateamento de óxidos e ataque ácido e mantida em solução de cloreto de sódio), Grupo Hidrofóbico - HFB (instalação de implante com superfície modificada por jateamento de óxidos e ataque ácido) e Grupo Usinado - U (instalação de implante com superfície usinada). No período de 45 dias após os procedimentos cirúrgicos de instalação dos implantes, os animais foram submetidos à eutanásia, e as tíbias foram removidas, sendo realizado o processamento histológico para amostras não descalcificadas. Após a obtenção das lâminas, foi realizada a análise histomorfométrica para avaliar as porcentagens de contato osso-implante (% BIC) e da área óssea entre as espiras (% BBT). As mensurações foram realizadas em duas diferentes regiões: 1) as roscas do implante na região do osso cortical e 2) todas as roscas do implante inseridas no osso (cortical e medular). A análise estatística foi feita por meio de ANOVA One-Way, seguida pelo teste de Tukey para análise inferencial dos dados. Resultado Quando o BIC e o BBT foram analisados de forma independente nas regiões cortical e trabecular/total, observou-se uma diferença no comportamento histológico dos implantes de acordo com o tratamento de superfície. Os implantes HFL apresentaram BIC (%) trabecular 16,85% maior (p = 0,02) do que os implantes HFB e 26,12% maior (p ≤ 0,0001) do que os implantes usinados. Contudo, a região cortical de todos os grupos apresentou valores de BIC cortical significativamente maiores ao redor dos implantes, independentemente da superfície. Conclusão Os resultados obtidos demonstraram que a formação óssea peri-implantar foi superior nas análises realizadas apenas em osso cortical, se comparados aos valores obtidos na mensuração total (osso cortical somado ao medular). Também foi possível observar que, dentro da mesma superfície, os valores de BIC (%) foram superiores em osso cortical. Em relação às limitações do estudo, pode-se concluir que diferentes metodologias de análise histométrica da osseointegração ao redor de diferentes superfícies de implantes instalados em tíbias de ratos podem interferir nos resultados de osseointegração, independentemente da superfície analisada. 2 n 8 tíbia sódio, sódio , sódio) usinada. usinada . usinada) 4 eutanásia removidas descalcificadas lâminas ossoimplante % ( BBT. BBT) 1 medular. medular medular) OneWay, OneWay One Way, Way One-Way dados trabeculartotal trabecular/total observouse observou 1685 16 85 16,85 p 0,02 002 0 02 2612 26 12 26,12 0,0001 00001 0001 usinados Contudo periimplantar peri implantar estudo podese pode analisada 168 16,8 0,0 00 261 26,1 0,000 0000 000 16, 0, 26, 0,00

Abstract: This study investigated the frost resistance of concrete exposed to sulfate and acid attacks after two years. The cement content was selected as 300 kg/m3, 350 kg/m3, 400 kg/m3, 450 kg/m3, and 500 kg/m3 in this study. 100 mm cubic specimens were prepared for experiments. After the specimens were cured in the water at 20 ± 2 °C for 28 days, they were kept in the laboratory conditions at 20 ± 2 °C for 23 months+2 days. Then, these samples were subjected to freeze-thaw cycles after being exposed to 5% sodium sulfate, 5% magnesium sulfate, 1% sulfuric acid, and 2% sulfuric acid for four days. Thus, the samples were exposed to the four different combined attacks. Lastly, the mechanical properties, weight change, and relative dynamic modulus of elasticity of these specimens were determined. Furthermore, the SEM and EDS analyses were carried out on samples. This study found that the highest compressive strength, the highest ultrasonic pulse velocity, and the lowest weight loss were the samples with 500 kg/m3 cement content subjected to combined freeze-thaw and 1% acid attack.

Abstract: In this research, chemical durability performances of the alkali-activated slag (AAS), 50% ground granulated blast furnace slag and 50% fly ash (AFS), ordinary Portland cement (OPC), and geopolymer (GPC) concretes were investigated thoroughly under 5% sulfuric acid attack. All alkali-activated concrete specimens were produced considering the minimum binder content of 360 kg/m3 and the maximum alkali activator to binder ratio of 0.45 according to the XA3 environment given in EN 206-1 standard for OPC concrete. The visual inspection, weight change and compressive strength tests were performed to understand the influence of sulfuric acid attack on the resulting performances. Also, scanning electron microscope (SEM) and energy dispersive X-ray spectrometry (EDS) analyses were performed to examine the morphological variations in micro-scale. The mechanical performances and durability of alkali-activated concretes were also compared to the OPC concrete for structural utilization. The results revealed that AFS specimens showed the best durability, while GPC specimens exhibited the poorest durability. SEM/EDS results pointed out that AFS specimens exhibited denser and less porous microstructure, and the reductions in Al/Si and Ca/Si atomic ratios were observed under 5% sulfuric acid attack. In contrast, GPC specimens showed less dense and porous microstructure, and high aluminum leaching was observed. In addition, the wider interconnected macro cracks and high calcium leaching were observed in the AAS samples under 5% sulfuric acid attack. Finally, the AAS and AFS specimens can be utilized in structural applications, while GPC specimens should not be used with a minimum binder content proposed by EN 206-1 standard.

ABSTRACT Fly ash is used partially as a replacement to cement to make the concrete. Fly ash contains SiO2 and Al2O3, which contribute to increase the strength of concrete. In the current investigation, fly ash has been replaced with varying percentages of nanosize in concrete, and the strength of the resulting hardened concrete has been evaluated. The production of nanosized fly ash has been made by the ball milling process and the analyses has been completed using scanning electron microscope (SEM) and X-ray diffraction (XRD), in order to determine the chemical and physical composition of the nanoparticles of fly ash. The nano fly ash concrete (NFAC) have been undergone for the durability tests of acid, sulphate and chloride attack. The concrete with 23% of nano fly ash replaced with cement performs well against these adverse conditions. The comparison has been made between the conventional (CC), raw fly ash (RFAC) and NFAC. Nano fly ash makes concrete much denser and more resistant to cracking. So the durability behaviour of NFAC is much better than CC and RFAC. The percentage of reduction in strength after durability aspects is varies from 0.03% to 10.75% for the NFAC. SiO Al2O3 AlO Al O investigation evaluated SEM (SEM Xray X ray XRD, XRD , (XRD) (NFAC acid attack 23 conditions CC, (CC) RFAC (RFAC cracking 003 0 03 0.03 1075 10 75 10.75 Al2O (XRD 2 (CC 00 0.0 107 1 7 10.7 0. 10.

Resumo O objetivo deste foi o de avaliar o efeito de uma superfície modificada por jateamento e ataque ácido e mantida em solução isotônica em comparação a uma superfície lisa sobre a osseointegração de implantes em animais hiperglicêmicos. No estudo foram utilizados 64 ratos, que foram divididos em 4 grupos com 16 animais em cada, e que foram avaliados em dois períodos experimentais (15 e 45 dias), com 8 animais em cada grupo. Os grupos foram divididos de acordo com o tipo de implante que foi instalado na tíbia dos animais e a condição sistêmica dos mesmos: Grupo CM - Implantes maquinados instalados em animais saudáveis; Grupo CH - Implantes maquinados instalados em animais com hiperglicemia; Grupo HM - Implantes hidrofílicos instalados em animais saudáveis, Grupo HH- Implantes hidrofílicos instalados em animais com hiperglicemia. Foram realizadas análises: biomecânicas (contra torque de remoção dos implantes), histométricas (avaliação do contato do osso com os implantes e da área de formação óssea entre as roscas) e microtomográfica (avaliação da área óssea ao redor dos implantes). Foi verificado que os implantes com superfície hidrofílica apresentaram maiores torques de remoção, quantidade de osso ao redor dos implantes e maiores valores de %BIC e %BBT em animais normo e hiperglicêmicos. Conclui-se que a superfície hidrofílica acelera o processo de osseointegração (~15% de %BIC/%BBT aos 15 dias), especialmente em animais com hiperglicêmicos. A superfície hidrofílica igualou a osseointegração entre animais normo- e hiperglicêmicos, revertendo o potencial negativo da hiperglicemia no processo de osseointegração.

Abstract The purpose of this study was to evaluate the effect of a surface modified by blasting and acid attack and maintained in an isotonic solution compared to a machined surface on osseointegration in normo- and hyperglycaemic animals. Sixty-four animals were allocated into 4 groups with 16 animals each, and they were subdivided into two experimental periods (15 and 45 days), with 8 animals in each group. The groups were divided according to the type of implant that was installed in the animals' tibia and the animals’ systemic condition: CM - Machined implants placed in Healthy animals; CH - Hydrophilic implants placed in Healthy animals, HM - Machined implants placed in animals with hyperglycaemia; HH- Hydrophilic implants installed in animals with hyperglycaemia. The following analyses were performed: biomechanical (removal torque), microtomographic (evaluation of the bone volume around the implants- BV/TV), and histomorphometric (evaluation of bone-implant contact BIC% and of the bone formation area between the threads BBT%). It was found that the implants with hydrophilic surfaces presented higher removal torques and quantities of BV/TV% and higher BIC% and BBT% values in normo- and hyperglycaemic animals. The results of this study indicated that the hydrophilic surface accelerates the osseointegration process (~ 15% BIC/BBT at 15-day period), especially in animals with hyperglycaemia. The hydrophilic surface equaled the osseointegration between normo- and hyperglycaemic animals, reversing the negative potential of hyperglycaemia on the osseointegration process.

Resumo Este trabalho apresenta o estudo realizado em uma Estação Elevatória de Esgoto após ser constatado severa degradação. O ataque por ácido sulfúrico biogênico em sistemas de esgoto sanitário é amplamente estudado na literatura, entretanto, dados em situações reais de obra ainda são bastante limitados. Foram realizadas análises da concentração de H 2 S no ar, profundidade de carbontação, ensaio de resistência à compressão, petrografia, MEV/EDS, DRX e determinações químicas em testemunhos de concreto extraídos acima do nível do efluente. Os produtos identificados na superfície foram Gipsita, Jarosita, Hidróxido Ferroso, Cloreto Ferroso e possivelmente Hisingerita. Os resultados demonstram a presença na superfície tanto de produtos oriundos da dissolução da pasta cimentícia quanto das barras de aço de 16 mm localizadas na região atacada.

Abstract This work presents the study carried out in a Sewage Pumping Station after severe degradation was observed. The attack by biogenic sulfuric acid in sanitary sewage systems is widely studied in the literature, however, data on real work situations are still quite limited. Analyzes of the concentration of H 𝟐 𝐒 in the air, carbonation depth, compressive strength, petrography, SEM/EDS, XRD and chemical determinations were carried out in concrete cores extracted above the effluent level. The products identified on the surface were Gypsum, Jarosite, Ferrous Hydroxide, Ferrous Chloride and possibly Hisingerite. The results demonstrate the presence of products on the surface, from the dissolution of cement paste as well as from the 16 mm steel bars located in the attacked region.

Resumen Este trabajo presenta el estudio realizado en una Estación de Bombeo de Aguas Residuales luego de que se observara una severa degradación. El ataque por ácido sulfúrico biogénico en los sistemas de alcantarillado sanitario es ampliamente estudiado en la literatura, sin embargo, los datos sobre situaciones reales de trabajo aún son bastante limitados. Se realizaron análisis de concentración de H 2 S en el aire, profundidad de carbonatación, prueba de resistencia a la compresión, petrografía, SEM/EDS, XRD y determinaciones químicas en núcleos de concreto extraídos por encima del nivel del efluente. Los productos identificados en la superficie fueron yeso, jarosita, hidróxido ferroso, cloruro ferroso y posiblemente hisingerita. Los resultados demuestran la presencia en la superficie de productos de la disolución de pasta de cemento y barras de acero de 16 mm ubicadas en la región atacada.

ABSTRACT Supplying sewerage systems in cities and factories has a high cost, both for design, execution, and maintenance. Reinforced concrete exposed to the aggressive acids produced by wastewater microorganisms receives high costly coatings to avoid corrosion and impairment of structural functions. Thus, this systematic review had two main goals: (1) to identify the supplementary cementitious materials (SCM) that improve concrete resistance to chemical sulfuric acid attack (H2SO4) and (2) to describe the performed tests to access concrete resistance to H2SO4 in laboratory conditions. After careful analysis of scientific references collected on indexed bases, the study showed that the test methods used to appraise samples resistance do not follow a standard protocol, hindering quantitative analysis between distinct studies results. In general, concrete resistance to H2SO4 is evaluated by immersing concrete samples in high concentrated acid solutions and assessing its compressive strength and mass change on a 28 or 30 days base sequence. Using SCMs improve resistance to sulfuric acid, and binders made with silica fume had the best results. This review may encourage the creation of test protocols to assess the resistance of concrete to H2SO4 that allow further statistical analysis of the research results. cost design execution maintenance functions Thus goals 1 (1 SCM (SCM HSO H SO (H2SO4 2 (2 H2SO conditions bases protocol results general 3 sequence ( (H2SO

RESUMO Prover esgotamento sanitário em cidades e fábricas possui custos elevados tanto de projeto, quanto de execução e de manutenção. O concreto armado exposto aos ácidos agressivos produzidos pelos microrganismos dos efluentes acabam recebendo revestimentos altamente custosos para evitar a corrosão e o comprometimento de suas funções estruturais. Assim, esta revisão sistemática teve dois objetivos principais: (1) identificar os materiais cimentícios suplementares (MCSs) que melhoram a resistência do concreto à corrosão por ácido sulfúrico de origem química (H2SO4) e (2) descrever as pesquisas laboratoriais realizadas para avaliar a resistência do concreto ao H2SO4. Após criteriosa análise das referências coletadas em bases indexadas, o estudo mostrou que os métodos utilizados para avaliar a resistência dos corpos de prova de concreto não seguem um protocolo padrão, o que dificulta a análise quantitativa dos resultados dos diferentes estudos. Em geral, a resistência do concreto ao H2SO4 é avaliada pela imersão dos corpos de prova em soluções com alta concentração de ácido e medição da resistência à compressão e da mudança de massa em períodos sequenciais de 28 ou 30 dias. O uso de MCSs aumenta a resistência ao ácido sulfúrico, sendo que os ligantes compostos por sílica ativa apresentam os resultados mais promissores. Espera-se que esta revisão encoraje a criação de protocolos de ensaio para avaliar a resistência do concreto ao H2SO4 que permitam uma análise estatística mais aprofundada dos resultados de diferentes pesquisas. projeto manutenção estruturais Assim principais 1 (1 (MCSs HSO H SO (H2SO4 2 (2 indexadas padrão estudos geral H2SO 3 dias promissores Esperase Espera se ( (H2SO

ABSTRACT Research in materials science and engineering has sought alternatives to improve the properties and characteristics of cementitious composites. Therefore, the use of nanoparticles, such as silica nanoparticles, has been a promising alternative in the nanocomposite segment, providing improvements in physical, chemical and durability properties, due to the change in the material’s microstructure. International studies have shown benefits with the incorporation of small amounts of nanosilica in concrete, cement pastes and mortar, however, there are divergences regarding the content and size of nanoparticles of incorporated silica, and their respective effects on the properties of the fresh and hardened state of the cement materials. Therefore, the present study aims to analyze the influence of the addition of silica nanoparticles in cementitious composites, from the verifications of mechanical strength, water absorption and exposure in aggressive environments, through an analysis between four cementitious composites, being a reference sample, and in the others, contents of 0.5%, 0.75% and 1.0% of nanosilica will be added in relation to the cement mass. The cementitious composites were analyzed using the compressive strength test at 3, 7 and 28 days, water absorption and acid etching, all at 28 days of curing. In view of the results obtained, it was verified that the addition of nanosilica promoted a greater densification of the cementitious matrix, therefore, it improved the compressive strength, reduced the water absorption and the acid attack in relation to the reference. Finally, among the mixtures evaluated, it is concluded that the composite with the addition of 0.5% of nanosilica presented the best contributions to the research, being an increase of 15.6% for compressive strength and a reduction of 4.9% for water absorption and 0.2% and 1.4% for acid attack by Miranda method and ASTM C-267-01, respectively. Therefore segment physical material s microstructure concrete mortar however environments sample others 05 0 5 075 75 0.75 10 1 1.0 mass 3 2 etching curing obtained matrix therefore Finally evaluated 0.5 research 156 15 6 15.6 49 4 9 4.9 02 0.2 14 1.4 C26701, C26701 C 267 01, 01 C-267-01 respectively 07 0.7 1. 0. 15. 4. C2670 26 C-267-0 C267 C-267- C26 C-267 C2 C-26 C-2 C-

RESUMO Pesquisas na área da ciência e engenharia dos materiais têm buscado alternativas para melhorar as propriedades e características dos compósitos cimentícios. Para tanto, o uso de nanopartículas, como as nanopartículas de sílica vem sendo uma alternativa promissora no segmento de nanocompósitos, proporcionando melhorias das propriedades físicas, químicas e na durabilidade, devido a alteração na microestrutura do material. Estudos internacionais têm demonstrado benefícios com a incorporação de pequenos teores de nanossílica em concretos, pastas de cimento e argamassa, entretanto, existem divergências quanto ao teor e ao tamanho de nanopartículas de sílica incorporada, e seus respectivos efeitos nas propriedades do estado fresco e endurecido dos materiais cimentícios. Diante disso, o presente estudo tem como objetivo analisar a influência da adição de nanopartículas de sílica em compósitos cimentícios, a partir das verificações da resistência mecânica, da absorção de água e da exposição em ambientes agressivos, através de uma análise entre quatro compósitos cimentícios, sendo uma amostra de referência, e nas demais serão adicionados teores de 0,5%, 0,75% e 1,0% de nanossílica em relação à massa de cimento. Os compósitos cimentícios foram analisados mediante o ensaio de resistência à compressão aos 3, 7 e 28 dias, absorção de água e ataque ácido, todos aos 28 dias de cura. Diante dos resultados obtidos verificou-se que a adição de nanossílica promoveu uma maior densificação da matriz cimentícia, logo, melhorou a resistência à compressão, diminuiu a absorção de água e o ataque ácido em relação à referência. Por fim, dentre as misturas avaliadas, conclui-se que o compósito com adição de 0,5% de nanossílica apresentou as melhores contribuições à pesquisa sendo, aumento de 15,6% para resistência à compressão e redução de 4,9% para absorção de água e 0,2% e 1,4% para o ataque ácido pelo método de Miranda e pela ASTM C-267-01, respectivamente. tanto nanocompósitos físicas durabilidade material concretos argamassa entretanto incorporada disso mecânica agressivos referência 05 0 5 075 75 0,75 10 1 1,0 3 2 cura verificouse verificou se cimentícia logo fim avaliadas concluise conclui 0,5 156 15 6 15,6 49 4 9 4,9 02 0,2 14 1,4 C26701, C26701 C 267 01, 01 C-267-01 respectivamente 07 0,7 1, 0, 15, 4, C2670 26 C-267-0 C267 C-267- C26 C-267 C2 C-26 C-2 C-