cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.14321832.v1
title: Elaboration of high temperature sintered hydroxyapatite for odontological applications

description: ABSTRACT Stoichiometric hydroxyapatite is a bioreabsorbable material and has been used for bone repair and shot blasting of titanium implants. However, the stoichiometric hydroxyapatite is not stable above 1130 oC to 1200 oC, limiting the heat treatment performed on the biomaterial to increase the mechanical strength of the granules obtained from the synthesis process at room temperature. Therefore, the aim of this work was the elaboration of calcium phosphate with Ca/P molar ratio of 1.7. With this Ca/P molar ratio, the formation of stable hydroxyapatite is possible up to approximately 1360 oC, according to the CaO-P2O5 equilibrium diagram. Calcium phosphate was prepared by the wet method of synthesis using calcium carbonate and phosphoric acid as raw materials. The material obtained from the synthesis consists of agglomerated particles with a size between 20 nm and 70 nm, while the size of the agglomerates varied from a few microns to approximately 200 µm. The results of the thermal analysis and X-ray diffraction showed that the hydroxyapatite is stable between 750 oC and 1350 oC. The heat treatment performed at 1300 oC confirmed that there is no transformation of hydroxyapatite into tricalcium phosphate above 1130 oC to 1200 oC as it happens for stoichiometric hydroxyapatite. In the heat treatment carried out at 1300 oC for 1 hour, hydroxyapatite was obtained with 67 % of porosity whereas in the treatment of 4 hours at the same temperature the porosity was 17 %. Hydroxyapatite with high porosity has applications in bone repair whereas the more compact hydroxyapatite can be used in the blasting of titanium implants. These applications are discussed in the work.
DOI: 10.6084/m9.figshare.14321836
title: Adsorption in Jar-Test system: a study of the physico-chemical interactions of the chitosan biopolymer with the textile dye DO 2GL

description: ABSTRACT The incorrect disposal of contaminated effluents from textile industries is a major contribution to their environmental impact. We aimed to use the chitosan biopolymer from industrial sources as a potential adsorbent agent. The experiments were performed in Jar-Test simulating an industrial scale treatment. Both pH and mass variations were analyzed. Our UV spectra results showed that all datasets fitted to the Langmuir model, indicating the formation of monolayers. Kinetics studies confirmed that adsorption follows a pseudo-second order model, in addition to a chemisorption pattern during adsorption. Kinetics studies also demonstrated intraparticle diffusion, which confirmed a strong adsorbate/adsorbent interaction with the dye. The Jar-Test proved to be an efficient system to simulate treatment of effluents on an industrial scale, thus ranking chitosan powder as a good adsorbent and eligible to future large-scale applications.
DOI: 10.6084/m9.figshare.14321836.v1
title: Adsorption in Jar-Test system: a study of the physico-chemical interactions of the chitosan biopolymer with the textile dye DO 2GL

description: ABSTRACT The incorrect disposal of contaminated effluents from textile industries is a major contribution to their environmental impact. We aimed to use the chitosan biopolymer from industrial sources as a potential adsorbent agent. The experiments were performed in Jar-Test simulating an industrial scale treatment. Both pH and mass variations were analyzed. Our UV spectra results showed that all datasets fitted to the Langmuir model, indicating the formation of monolayers. Kinetics studies confirmed that adsorption follows a pseudo-second order model, in addition to a chemisorption pattern during adsorption. Kinetics studies also demonstrated intraparticle diffusion, which confirmed a strong adsorbate/adsorbent interaction with the dye. The Jar-Test proved to be an efficient system to simulate treatment of effluents on an industrial scale, thus ranking chitosan powder as a good adsorbent and eligible to future large-scale applications.
DOI: 10.6084/m9.figshare.14321838
title: Production and characterization of cellulose by Glucanoacetobacter hansenii in medium containing glucose or mannitol

description: ABSTRACT The cellulose, polysaccharide of vegetable origin, is an abundant biopolymer found in nature and, therefore, a valuable tool for the science of materials applications in the medical, cosmetic, refinery, and other areas. As an alternative to traditional cellulose production, we have the microbial path, which results in a nanometric fiber with good mechanical properties. Among the several microorganisms that produce bacterial cellulose (BC), the one that presents very satisfactory results is the strictly aerobic and Gram-negative bacteria known as Gluconacetobacter hansenii (ATCC - 23769). This biopolymer presents enormous application potential due to its thermal, mechanical and biocompatibility properties. Many researches are being developed to optimize the productive processes of BC, resulting in greater conversions with a lower production cost. This work aimed to produce the cellulose membranes obtained in mannitol (C-MM) or Hestrin and Schramm (HS) (C-MH) medium and to characterize them through infrared spectroscopy (IR), thermogravimetric (TGA) and X-ray diffraction (XRD) analyses. The celluloses produced presented similar morphological images, but the mannitol medium had a higher yield (2.09 g. L-1) in the BC production when compared to the Hestrin and Schramm medium (HS) (1.15 g. L-1). In addition, the bacterial cellulose produced in medium containing mannitol presented higher crystallinity (78%) than that produced in Hestrin e Schramm (HS) (65%). Through the IR analysis, it was possible to confirm the functional groups present in the bacterial cellulose without any contaminants from the production process. Regarding the thermogravimetric analysis, the polymer formed from the mannitol medium presented higher thermal stability. Finally, the biofilms produced in the different medium had different properties, revealing that the polymeric characteristics change according to the bacterial growth medium.
DOI: 10.6084/m9.figshare.14321838.v1
title: Production and characterization of cellulose by Glucanoacetobacter hansenii in medium containing glucose or mannitol

description: ABSTRACT The cellulose, polysaccharide of vegetable origin, is an abundant biopolymer found in nature and, therefore, a valuable tool for the science of materials applications in the medical, cosmetic, refinery, and other areas. As an alternative to traditional cellulose production, we have the microbial path, which results in a nanometric fiber with good mechanical properties. Among the several microorganisms that produce bacterial cellulose (BC), the one that presents very satisfactory results is the strictly aerobic and Gram-negative bacteria known as Gluconacetobacter hansenii (ATCC - 23769). This biopolymer presents enormous application potential due to its thermal, mechanical and biocompatibility properties. Many researches are being developed to optimize the productive processes of BC, resulting in greater conversions with a lower production cost. This work aimed to produce the cellulose membranes obtained in mannitol (C-MM) or Hestrin and Schramm (HS) (C-MH) medium and to characterize them through infrared spectroscopy (IR), thermogravimetric (TGA) and X-ray diffraction (XRD) analyses. The celluloses produced presented similar morphological images, but the mannitol medium had a higher yield (2.09 g. L-1) in the BC production when compared to the Hestrin and Schramm medium (HS) (1.15 g. L-1). In addition, the bacterial cellulose produced in medium containing mannitol presented higher crystallinity (78%) than that produced in Hestrin e Schramm (HS) (65%). Through the IR analysis, it was possible to confirm the functional groups present in the bacterial cellulose without any contaminants from the production process. Regarding the thermogravimetric analysis, the polymer formed from the mannitol medium presented higher thermal stability. Finally, the biofilms produced in the different medium had different properties, revealing that the polymeric characteristics change according to the bacterial growth medium.
DOI: 10.6084/m9.figshare.14321839
title: pH effect on the synthesis of different size silver nanoparticles evaluated by DLS and their size-dependent antimicrobial activity

description: ABSTRACT This paper reports citrate-stabilized silver nanoparticles (AgNPs) synthesized by nitrate ion chemical reduction with sodium borohydride, at different pHs (2–9). The AgNPs synthesized by this method exhibited size distribution from 5 to 249 nm, depending on pH, as determined by dynamic light scattering, and morphology spherical, as determined by transmission electron microscopy. In pH range 3–7 occurred aggregation of the nanoparticles. The size distribution depending on pH was determined by dynamic light scattering. The zeta potential was determined, and the colloidal stability was correlated with nanoparticles aggregation at different pHs. The size-dependent antimicrobial activity was evaluated for two solutions, wherein both samples exhibited antimicrobial activity, although the smallest AgNPs without agglomeration have enhanced antimicrobial properties.
DOI: 10.6084/m9.figshare.14321839.v1
title: pH effect on the synthesis of different size silver nanoparticles evaluated by DLS and their size-dependent antimicrobial activity

description: ABSTRACT This paper reports citrate-stabilized silver nanoparticles (AgNPs) synthesized by nitrate ion chemical reduction with sodium borohydride, at different pHs (2–9). The AgNPs synthesized by this method exhibited size distribution from 5 to 249 nm, depending on pH, as determined by dynamic light scattering, and morphology spherical, as determined by transmission electron microscopy. In pH range 3–7 occurred aggregation of the nanoparticles. The size distribution depending on pH was determined by dynamic light scattering. The zeta potential was determined, and the colloidal stability was correlated with nanoparticles aggregation at different pHs. The size-dependent antimicrobial activity was evaluated for two solutions, wherein both samples exhibited antimicrobial activity, although the smallest AgNPs without agglomeration have enhanced antimicrobial properties.
DOI: 10.6084/m9.figshare.14321841
title: Effect of chemical and thermochemical treatments on the surface properties of commercially pure titanium

description: ABSTRACT Chemical and physical methods have been generally used for modifying the surface of titanium implants with the aim of achieving better osseointegration. In this work, an evaluation of the effect of different chemicals and thermochemical treatments on the surface modification of titanium was carried out. Plates of commercially pure titanium were polished and treated with four different methods. Scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, X-ray diffraction and drop shape analysis were used to characterize the modified titanium surface. Our results showed that the AEPTTT surface exhibited the highest Ra values followed by AEAT, AEPT, polished Ti and AE samples. In addition, the AEAT and AEPTTT treatments developed the largest surface area, while the AE treatment produced the lowest surface area. Furthermore, the AEAT treatment created the most hydrophilic surface, which is known to positively affect the osseointegration rate of dental implants.
DOI: 10.6084/m9.figshare.14321841.v1
title: Effect of chemical and thermochemical treatments on the surface properties of commercially pure titanium

description: ABSTRACT Chemical and physical methods have been generally used for modifying the surface of titanium implants with the aim of achieving better osseointegration. In this work, an evaluation of the effect of different chemicals and thermochemical treatments on the surface modification of titanium was carried out. Plates of commercially pure titanium were polished and treated with four different methods. Scanning electron microscopy, atomic force microscopy, energy-dispersive X-ray spectroscopy, infrared spectroscopy, X-ray diffraction and drop shape analysis were used to characterize the modified titanium surface. Our results showed that the AEPTTT surface exhibited the highest Ra values followed by AEAT, AEPT, polished Ti and AE samples. In addition, the AEAT and AEPTTT treatments developed the largest surface area, while the AE treatment produced the lowest surface area. Furthermore, the AEAT treatment created the most hydrophilic surface, which is known to positively affect the osseointegration rate of dental implants.
DOI: 10.6084/m9.figshare.14321842.v1
title: Ultrasonication effect of silica fume and colloidal nanosilica on cement pastes

description: ABSTRACT The high performance cementitious materials can be produced using silica fume (SF) and nanosilica (NS). Due to the small size of their particles, these materials became agglomerate, reducing their reactivity potentials. Some researchers have studied methods of dispersing these particles as ultrasonicators and rotational mixers, but studies on these materials are still needed, especially on the effect of colloidal nanosilica ultrasonication. Thus, this article aimed to evaluate the effect of ultrasonication (use of high energy ultrasound) of silica fume and colloidal nanosilica on cement pastes. Five pastes were investigated, a reference with 100% Portland cement CP V-ARI, and other four replacing 2% and 10% of the Portland cement by colloidal nanosilica and silica fume, respectively, in their natural state and after ultrasonication. The tests of compressive strength, thermogravimetry analysis (TGA), infrared spectroscopy and mercury intrusion porosimetry (MIP) were performed on pastes. The results showed that the use of colloidal NS in substitution of Portland cement increased C-S-H production, pore refinement and compressive strength of the pastes, however the use of SF in its natural state increased the pore size and decreased the mechanical performance of the pastes due to the agglomeration of its particles. By ultrasonication of SF, there was higher C-S-H production, pore refinement and compressive strength when compared to SF paste without the ultrasonication process, proving the effectiveness of this method for the dispersion of these particles. Nevertheless, ultrasonication of colloidal nanosilica did not result in significant differences in the microstructure and mechanical performance of the pastes.
DOI: 10.6084/m9.figshare.14321844.v1
title: Study of the effect of solvent on acetylate cashew gum-based nanoparticles properties and antimicrobial activity

description: ABSTRACT The aim of this work was to investigate the influence of acetone and dimethyl sulfoxide (DMSO) on acetylated cashew gun (aCG) nanoparticles parameters and to assess their antimicrobial activity. C1 nanoparticles presented smaller size (81.3 nm) than compared to C2 (115.7 nm). Although, acetone formed particles with lower PDI value. Both C1 and C2 presented negative zeta potential (-39.8 and -31.7 respectively). Particle tracking analysis showed that C1 was slightly more concentrated than C2. No statistical differences (p &lt; 0.05) between the same samples after 5 months were found. Both samples did not exert inhibitory effect on E. coli, on the contrary S. aureus, in which both C1 (36.9%) and C2 (19.9%) provided important inhibitory effect. C1 presented a more pronounced antifungal effect (81.2%), compared to C2 (18.8%), indicating a promising platform to be used in several biomedical application.
DOI: 10.6084/m9.figshare.14321844
title: Study of the effect of solvent on acetylate cashew gum-based nanoparticles properties and antimicrobial activity

description: ABSTRACT The aim of this work was to investigate the influence of acetone and dimethyl sulfoxide (DMSO) on acetylated cashew gun (aCG) nanoparticles parameters and to assess their antimicrobial activity. C1 nanoparticles presented smaller size (81.3 nm) than compared to C2 (115.7 nm). Although, acetone formed particles with lower PDI value. Both C1 and C2 presented negative zeta potential (-39.8 and -31.7 respectively). Particle tracking analysis showed that C1 was slightly more concentrated than C2. No statistical differences (p &lt; 0.05) between the same samples after 5 months were found. Both samples did not exert inhibitory effect on E. coli, on the contrary S. aureus, in which both C1 (36.9%) and C2 (19.9%) provided important inhibitory effect. C1 presented a more pronounced antifungal effect (81.2%), compared to C2 (18.8%), indicating a promising platform to be used in several biomedical application.
DOI: 10.6084/m9.figshare.14321842
title: Ultrasonication effect of silica fume and colloidal nanosilica on cement pastes

description: ABSTRACT The high performance cementitious materials can be produced using silica fume (SF) and nanosilica (NS). Due to the small size of their particles, these materials became agglomerate, reducing their reactivity potentials. Some researchers have studied methods of dispersing these particles as ultrasonicators and rotational mixers, but studies on these materials are still needed, especially on the effect of colloidal nanosilica ultrasonication. Thus, this article aimed to evaluate the effect of ultrasonication (use of high energy ultrasound) of silica fume and colloidal nanosilica on cement pastes. Five pastes were investigated, a reference with 100% Portland cement CP V-ARI, and other four replacing 2% and 10% of the Portland cement by colloidal nanosilica and silica fume, respectively, in their natural state and after ultrasonication. The tests of compressive strength, thermogravimetry analysis (TGA), infrared spectroscopy and mercury intrusion porosimetry (MIP) were performed on pastes. The results showed that the use of colloidal NS in substitution of Portland cement increased C-S-H production, pore refinement and compressive strength of the pastes, however the use of SF in its natural state increased the pore size and decreased the mechanical performance of the pastes due to the agglomeration of its particles. By ultrasonication of SF, there was higher C-S-H production, pore refinement and compressive strength when compared to SF paste without the ultrasonication process, proving the effectiveness of this method for the dispersion of these particles. Nevertheless, ultrasonication of colloidal nanosilica did not result in significant differences in the microstructure and mechanical performance of the pastes.
DOI: 10.6084/m9.figshare.14321847.v1
title: Soybean and babassu biodiesel production: a laboratory scale study and an exergy analysis approach

description: ABSTRACT The emission of gases from the fleet of vehicles is one of the main sources of the environmental impact of the planet. Reversing this scenario, environmental awareness and a search for alternative sources of energy has been growing exponentially in recent years. In this context, the production of biofuels presents itself as an alternative for the lowest environmental impact, energy, and economy, with emphasis on biodiesel. The scale of production of this biofuel, the options related to the raw materials and their conditions are intertwined with the energy and exergetic efficiencies of the process. Therefore, no work was constructed as an analysis of the biodiesel production processes of soybeans and babassu, in which they were conducted on a laboratory scale. According to the results, the production of soybean biodiesel arose in exergetic efficiency of 73.25% and the production of biodiesel from babassu of 74.72%.
DOI: 10.6084/m9.figshare.14321847
title: Soybean and babassu biodiesel production: a laboratory scale study and an exergy analysis approach

description: ABSTRACT The emission of gases from the fleet of vehicles is one of the main sources of the environmental impact of the planet. Reversing this scenario, environmental awareness and a search for alternative sources of energy has been growing exponentially in recent years. In this context, the production of biofuels presents itself as an alternative for the lowest environmental impact, energy, and economy, with emphasis on biodiesel. The scale of production of this biofuel, the options related to the raw materials and their conditions are intertwined with the energy and exergetic efficiencies of the process. Therefore, no work was constructed as an analysis of the biodiesel production processes of soybeans and babassu, in which they were conducted on a laboratory scale. According to the results, the production of soybean biodiesel arose in exergetic efficiency of 73.25% and the production of biodiesel from babassu of 74.72%.
DOI: 10.6084/m9.figshare.14321848
title: Production of biosurfactant by Lysinibacillus sp. and Bacillus sp. from different oils as carbon source

description: ABSTRACT Biosurfactants are multifunctional molecules produced by microorganisms and havea some advantages compared to synthetic surfactants, such as low toxicity, high biodegradability ,improved tensoactivity and chemical diversity. However, commercial scale production is not viable due to the high cost of the substrates used. Therefore, in the present work we evaluated the production of biosurfactants using different oils as carbon source, such as soybean oil, frying oil, diesel oil, new and used lubricating oil, from two genera of bacteria isolated from sludge cosmetics industry and soil contaminated with diesel oil, Lysinibacillus sp. and Bacillus sp. respectively. These were identified by sequencing the 16S rRNA gene fragment and kept under refrigeration at 4 ° C in test tubes with tryptone soy agar. The production was carried out under agitation at 200 rpm at 30 °C for 7 days. The biosurfactant production was analyzed by emulsifying activity, emulsification index and drop collapse. The bacteria used produced biosurfactant in all types of oils tested. Soybean oil was the best substrate for the production of biosurfactant from Lysinibacillus sp. and Bacillus sp. with an emulsification index of 50% and 46.63%, respectively.
DOI: 10.6084/m9.figshare.14321848.v1
title: Production of biosurfactant by Lysinibacillus sp. and Bacillus sp. from different oils as carbon source

description: ABSTRACT Biosurfactants are multifunctional molecules produced by microorganisms and havea some advantages compared to synthetic surfactants, such as low toxicity, high biodegradability ,improved tensoactivity and chemical diversity. However, commercial scale production is not viable due to the high cost of the substrates used. Therefore, in the present work we evaluated the production of biosurfactants using different oils as carbon source, such as soybean oil, frying oil, diesel oil, new and used lubricating oil, from two genera of bacteria isolated from sludge cosmetics industry and soil contaminated with diesel oil, Lysinibacillus sp. and Bacillus sp. respectively. These were identified by sequencing the 16S rRNA gene fragment and kept under refrigeration at 4 ° C in test tubes with tryptone soy agar. The production was carried out under agitation at 200 rpm at 30 °C for 7 days. The biosurfactant production was analyzed by emulsifying activity, emulsification index and drop collapse. The bacteria used produced biosurfactant in all types of oils tested. Soybean oil was the best substrate for the production of biosurfactant from Lysinibacillus sp. and Bacillus sp. with an emulsification index of 50% and 46.63%, respectively.
DOI: 10.5281/zenodo.4639947
title: Coseismic fault lubrication by viscous deformation

description: This dataset contain the mechanical data of experiments displayed in "Coseismic fault lubrication by viscous deformation". Files type is csv.
DOI: 10.5281/zenodo.4639946
title: Coseismic fault lubrication by viscous deformation

description: This dataset contain the mechanical data of experiments displayed in "Coseismic fault lubrication by viscous deformation". Files type is csv.