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Wound healing is a complex biological process. In this context, hyaluronic acid (HA) plays an important role in all phases of wound healing, from inflammation to the remodelling process. Nevertheless, its presence in adults decreases by 50% compared to newborns, which drastically reduces tissue regeneration. In this sense, this work presented a new method of extracting HA from chicken combs, as well as the development and in vivo evaluation of an ointment composed of vaseline, lanolin and HA 1% (w/w) for wound healing. The rheological analysis showed that the ointment containing HA has a viscoelastic behaviour. The in vivo test showed on the 7th day that the group treated with the ointment containing HA had a wound area of 0.07 cm2 against 0.09 cm2 of the ointment without HA (vaseline, and lanolin). On the other hand, the groups treated with the HA ointment had a higher mean percentage of collagen and better healing on the 14th day. The results of this paper indicate that the new method used to obtain HA is feasible, low-cost, and easy to obtain. Furthermore, the HA containing ointment improved wound healing. Therefore, the obtained ointment has great potential for use as an effective biomaterial in wound healing. [ABSTRACT FROM AUTHOR]

Two different sulfonating agents: sulfuric acid (S) and acetyl sulfate (AcS) were evaluated for chemical modification of poly (styrene-co-butyl acrylate) (StBuA) copolymer, as low-cost membranes. The reaction was carried out by direct sulfonation during 2–5 h of sulfonation time. FTIR confirmed sulfonation through the presence and widening of the several SO 3 H characteristic absorption bands. The molecular weight decreased after sulfonation, compared with pristine StBuA. TGA thermal analysis showed stability over 150 ᵒC with residues suggesting crosslinking and a glass transition (T g) enhanced. Even with higher T g values, sulfonated copolymers became flexible, as seen by their lower complex modulus (E∗). Ion exchange capacity (IEC) ranged from 0.91 to 1.53 meq g−1 and degree of sulfonation (DS) from 7 to 40%. The proton conductivity for sulfonated membranes exhibited similar or higher to Nafion membrane, particularly for S-4h membranes. A Grotthuss mechanism is envisaged for AcS and vehicular mechanism for S membranes. • Poly (styrene- co -butyl acrylate) sulfonation with sulfuric acid and acetyl sulfate. • Sulfonated copolymers have both good thermal stability and flexibility. • High proton conductivity for sulfonated styrene copolymer membranes. [ABSTRACT FROM AUTHOR]

Several studies evaluate the use of cutting fluids in the machining processes (turning and milling) of hardened steels. However, few studies evaluate the physical and chemical properties of vegetable oils and their formulations as possible cutting fluids in grinding AISI 4340 steel. Therefore, this work evaluated the use of vegetable oils (soybean and corn) and their formulations to replace the mineral cutting fluid in the grinding of AISI 4340 steel. The physicochemical analyses (acidity and refractive index, density, and viscosity) indicated that the vegetable oils and their formulations are stable and viable even after storage for 600 or 720 h; they present good physicochemical qualities. The infrared spectroscopy showed possible signs of oxidation of the fluids after storage, however, did not affect their performance. The TGA and DSC thermal analyses showed that the vegetable oils and their formulations have greater thermal stability than the mineral cutting fluid. The machining parameters (grinding wheel wear and roughness) showed that Mix-1 was superior to mineral cutting fluid by 17% and 10%, respectively. Besides, it showed that SN and CR-A5 are promising candidates to replace the mineral cutting fluid. Therefore, this study showed that vegetable oils (soybean and corn) and their formulations can be used in grinding AISI 4340 steel, because they are thermally stable, have good machining properties, are biodegradable, non-toxic, and low cost when compared to mineral cutting fluid widely used in industrial machining. [ABSTRACT FROM AUTHOR]

This paper aims to think about two main points: exploring the reflective contributions to teacher education and observing the didactic possibilities for teaching through Japanese comics (Mangá) titled Assassination Classroom, by Yusei Matsui. Thus, the intent of this research is to conceive the Mangá as a bridge to imagination: either to discuss the human condition in the adventure of teaching - about its responsibilities and its limitations, or to understand the value that lies in nurturing and developing affectiveknowledge relations with students, with the intention of welcoming and caring in order to better teach how to live and exist in society. [ABSTRACT FROM AUTHOR]

The aim of this study is to analyze the discursive positions about human rights in statements discourses present on the web, in order to investigate which relations of knowledge and power and will of truth go through these positions. To this end, we analyzed two materialities available on the web (a post from BG's blog and a text from the website Justifying, besides six online comments, three of each materiality). The theoretical framework that guides the present work rests within the scope of Foucault's discursive studies. From a methodological point of view, this research follows a descriptive-interpretative character, of a qualitative nature. The analyzes denote the existence of discursive shocks in the construction of wills of truth about human rights, which, on the one hand, defend that these rights are directed at a specific portion of the population and, on the other hand, attest to the collective character of these guarantees [ABSTRACT FROM AUTHOR]

Styrene-butyl acrylate (St-BuA) copolymers were obtained by mass free radical copolymerization reactions, using BPO as initiator. A 70:30 (St-BuA) comonomer composition was selected. Three different molar concentrations of sulfonating agent (50, 100 and 150%) were considered to obtain the sulfonated copolymer (sSt-BuA) and membranes were casted from sSt-BuA copolymers. Copolymers were characterized with FTIR, TGA and NMR 1H and mechanically by TMA. The sSt-BuA sulfonation degree (SD) effect on the ion-exchange capacity (IEC) was evaluated by titration and water uptake (WU) by gravimetry. Microstructure was also observed using scanning electron microscopy (SEM), and its electrochemical properties were evaluated by electrochemical impedance spectroscopy (EIS). The chemical composition of St-BuA copolymer was confirmed by proton nuclear magnetic resonance (NMR 1H) spectroscopy. Fourier transformed infrared spectroscopy (FT-IR) and thermal gravimetric analysis (TGA) analysis also confirmed the existence of both comonomers and a successful sulfonation up to an actual 30% level, as well as a good thermal stability over 300 °C for the molecular structure and over 150 °C for sulfonated membranes. TMA indicate an increase in flexure modulus along degree of sulfonation. SEM images show a highly dense material with low pore size for the sulfonated copolymer. The IEC values obtained varied from 0.83 to 1.18 meq g−1, depending on sulfonation degree. The proton conductivity for St-BuA 50% membrane (9.77 × 10−5 S cm−1) was a two order of magnitude lower than the commercial Nafion membrane (4.53 × 10−3 S cm−1). Thermal, mechanical and electrochemical results demonstrate that these sSt:BuA copolymers are promising materials to be used as membranes in fuel cells applications. • Styrene-butyl acrylate copolymers were synthetized and sulfonated. • The resulting membrane present good thermal and electrochemical properties. • The flexure modulus increase along degree of sulfonation. • Increasing sulfonation level increases proton conductivity. [ABSTRACT FROM AUTHOR]

Electrospinning is a versatile technique for fabricating polymeric fibers with diameters ranging from micro- to nanoscale, exhibiting multiple morphologies and arrangements. By combining silk fibroin (SF) with synthetic and/or natural polymers, electrospun materials with outstanding biological, chemical, electrical, physical, mechanical, and optical properties can be achieved, fulfilling the evolving biomedical demands. This review highlights the remarkable versatility of SF-derived electrospun materials, specifically focusing on their application in tissue regeneration (including cartilage, cornea, nerves, blood vessels, bones, and skin), disease treatment (such as cancer and diabetes), and the development of controlled drug delivery systems. Additionally, we explore the potential future trends in utilizing these nanofibrous materials for creating intelligent biomaterials, incorporating biosensors and wearable sensors for monitoring human health, and also discuss the bottlenecks for its widespread use. This comprehensive overview illuminates the significant impact and exciting prospects of SF-derived electrospun materials in advancing biomedical research and applications. [Display omitted] • A critical review of silk fibroin (SF) electrospun materials is presented. • Applications include tissue regeneration and drug delivery systems. • Applications in smart materials and wearable sensors are also discussed. • We also highlight the potential future trends and commercialization prospects. [ABSTRACT FROM AUTHOR]

Considering the most varied discourses, currently constructed about romantic relationships that emerge by means of electronic devices, particularly flirting applications, the present text aims, from the analysis of some discursive materialities that circulated in digital media, to investigate the production of subjectivity in discourses about virtual love. For this purpose, we analyzed three media discursive materialities (two reports and a section of a magazine column). Methodologically, the present study follows a descriptive-interpretative bias, with a qualitative approach. The analysis, based on the theoretical perspective of Michel Foucault, demonstrated that, given the specificities of each studied materiality, there is the constant subjectivity production of the digital technologies user with regard specifically to the mutations in the construction of virtual love as a discourse object. [ABSTRACT FROM AUTHOR]

The idea of virility compared to current modes of reframing attitudes, practices and behaviors historically linked to a virile culture is discussed. The object of analysis comprises discourses on the lumbersexual person in the social media to problematize the discursive frenzy as a reconfiguration symptom of virility, engendered in/by history and, therefore, susceptible to changes and rearrangements. [ABSTRACT FROM AUTHOR]

Topics that constitute the enunciation of Humanizing Networks in the various visibility areas of the WEB are discursively analyzed. Current analysis is foregrounded on Foucault's theories on discourse of knowledge and biopower / biopolitics. Through the enunciation series, certain directions that point towards the functioning of biopolitical strategies are investigated so that the focused movement disseminates respect and solves the issues on human rights and on the subjects' life. [ABSTRACT FROM AUTHOR]

We have been living in a historical period in which digital technologies have occupied a relevant position. Human communication is now related to the immense utilization of these technologies. In this sense, the school cannot be absent from proposing educational positions concerning the diversity of genres that comes from the digital sphere, in a way that enables the students to be engaged satisfactorily in various literacy practices. The digital genres are predominantly hybrid and hypermediatic and are characterized as relatively stable forms that denote the multiliteracy phenomenon, which has been discussed in the educational settings. Due to our interest in these issues, we proposed an analysis on the treatment of the digital genres in textbooks of the Portuguese Language (PL) in Ensino Médio (High School). For doing so, we concentrated our investigative focus on three PL's textbooks which are part of a collection approved by The National Program of Educational Book for Ensino Médio in Brazil. In this qualitative descriptive-interpretive research, we noticed that: (i) the analyzed textbooks explore mainly genres considered prototypical of the digital sphere (email and blog) and do not explore the diversity of genres of this sphere; (ii) in some points of the analysis, it was possible to notice a treatment that does not consider the fact that many students, or teachers, are not still properly prepared for a more consistent work with these genres. [ABSTRACT FROM AUTHOR]

In this work, we analyze some statements that have circulated in the media, specifi cally in Brazilian weekly magazines, such as Veja, Istoé and Época, which discusses a kind of alert to internet users about the danger originating from social networks, of the effects of wild exposure in the web, of spells that probe the cyberspace and indicate the facets of a society marked greatly by vigilance. In general lines, a discourse of risk, according to which all can potentially suffer the harmful consequences brought about by digital. Following a slant largely foucaultian, we try to trace the conditions of possibility that bring out the eruption of this discourse of caution related to the web, taking into account the ways in which the media takes on an educational role, in the sense to direct the behaviors of the users of digital technologies in their forays into cyberspace. [ABSTRACT FROM AUTHOR]

The media has mad in recent years, a sophisticated device that pushes the subjects to talk/write about themselves. Taking into account this observation, we propose in this article, from the analysis of the discourse of materialities media, investigating the formation of a writing itself (FOUCAULT, 1992) contemporany, supported with an ongoing exhibition of aspects that were once restricted to private life. [ABSTRACT FROM AUTHOR]

Polyelectrolytic membranes, such as the well-known commercial grade Nafion™, suffer mechanical failure and chemical decomposition after many hours of operation into a fuel cell. Mechanically due to expansion–contraction phenomena during water management and chemically due to the hydrogen peroxide and radicals produced from the H2/O2 redox electrochemical reactions. Considering that such behavior exists for the most used and reliable Nafion™ membranes, it is also expected similar properties depletion for alternative membrane copolymers. In this work, we examined the performance of sulfonated Styrene/butyl acrylate (S-St-BuA) copolymers during proton exchange activity through redox electrochemical reactions and their interactions with Fenton's reagent (H2O2/FeCl2), compared with Nafion™. In situ, FTIR is a simultaneous analysis that evaluates the spectroscopic characteristics while the proton exchange into membranes is also measured. The in situ FTIR analysis showed chemical stability in the structure of the alternative membranes of S-St/BuA, compared with Nafion™ when both were exposed to Fenton's reagent. [ABSTRACT FROM AUTHOR]

In this study we prepared annatto-loaded cellulose acetate nanofiber scaffolds and evaluated both in vitro cytotoxicity and potential for wound healing in a rat model. Annatto extract, which has been used to accelerate wound healing, was added to cellulose acetate polymer and the resulting material was used to produce nanofiber scaffolds via electrospinning. Physicochemical, and thermal evaluation of the resulting nanofiber mats showed that incorporating annatto did not significantly affect the thermal or chemical stability of the polymer. Annatto extract did not demonstrate cytotoxicity in the HET-CAM assay or MTT assay for fibroblast culture. Scanning electron microscopy of the fibroblasts confirmed that cells spread and penetrated into the nanofiber. In vivo experiments confirmed that cellulose acetate retained its biocompatibility when associated with crude annatto extract, and suggested that dose/response modulation occurs between the annatto-functionalized nanofibers and mast cells, indicating the potential of this material for wound healing applications. • Crude annatto extract loaded cellulose acetate nanofibers with properties ideal for potential wound healing applications; • Annatto loaded cellulose acetate nanofibers have promoted fibroblast cellular proliferation; • The fibroblasts cells attached, spread, and penetrate into the nanofibers scaffolds after 48 hours, • The bioactive molecules present in the nanofibers seem to modulate the inflammatory process in vivo. [ABSTRACT FROM AUTHOR]

The accelerated growth of the industrial sector has resulted in the consumption of large amounts of non-renewable resources. Accordingly, this study evaluated the tribological behaviour of polymeric matrix composites the ultra-high molecular weight polyethylene incorporated with waste from the grinding process. The results obtained showed that these materials can be produced easily. The presence of the residue favoured an increase in the degree of crystallinity estimated at 32–45%, as well as the reduction of the friction coefficient. The tensile test showed that the presence of the metallic microparticles affects the behaviour mechanical of the composites. The micrographs evidenced the abrasion and adhesion wear mechanisms and the rolled-up wear particles phenomenon. On the other hand, the roughness affected the behaviour of the wear mechanisms in a nonlinear way. Therefore, this work showed the ease of obtaining environmentally friendly composites presenting a viable alternative to waste machining disposal. [ABSTRACT FROM AUTHOR]

In this work, N-alkylated tetrazole copolymers were prepared to produce the solid polymeric electrolytes StVTz-82, StVTz-82:4C, StVTz-82:6C, StVTz-82:8C and StVTz-82:sultone. The chemical structure was confirmed by FTIR, H NMR, C NMR and GPC. GPC thermal analysis showed that the membranes are thermally stable up to 160 °C. DSC was used to evaluate the structural effect on the Tg value. Water absorption (WU) and ion exchange capacity (IEC) were conducted for all electrolytes. We observed a decrease in the elastic modulus with the introduction of side alkyl chains linked to the tetrazole heterocycle. The ionic conductivity of these materials was studied by electrochemical impedance spectroscopy. We observed that the StVTz-82 and StVTz-82:sultone copolymers, in hydrated conditions and at room temperature, are the ones that present the best conductivity values 2.09 and 9.78 mS. cm, respectively. Relating to the hydration number (λ), the StVTz-82:sultone electrolyte has a higher λ value. It also has sulfonic acid group, which has a lower pKa value (~ 1.9) then tetrazole (~ 4.50). From the point of view of mechanical properties, the StVTz-82:sultone electrolyte has a rigidity modulus intermediate to that of StVTz-82, which is more rigid, and StVTz-82:8C, which is the most flexible. These characteristics provide suitable properties for use of StVTz-82:sultone as a solid electrolyte for power generation devices such as fuel cells and batteries. [ABSTRACT FROM AUTHOR]

The development of new cutting tool materials favors the hardened steel turning process, which has in some cases replaced the grinding process. Thus, this study evaluates the machined surface of hardened AISI 4340 steel via turning and grinding operations. The turning process evaluated the effects of the cutting tools (material, grade, and coating) and the process parameters (cutting speed and cooling condition). In the grinding process, the effects of the plunge rates and volumes of removed material Zw were evaluated. The machined surface was evaluated by amplitude roughness (Ra, Rt, Rp, and Rz), functional (Kp, Rk, Rpk, and Rvk), and statistical parameters (Rsk and Rku) and by the type and magnitude of induced residual stress (compression and tensile). In general, the turning process displayed the best results in the roughness parameters by promoting a better surface finish, mainly when the parts were machined at a cutting speed of 300 m/min. The increased cutting speed provided better surface integrity. The ceramic tool CC6050 presented the best performance, followed by the polycrystalline boron nitride (PCBN) and ceramic CC650 tools under cooling and dry cutting conditions. With respect to the residual stress, the grinding process induced compressive residual stresses in all tested conditions. On the other hand, turning-induced tensile stresses when using ceramic cutting tools (class CC650 and CC6050) and compressive stresses when using a PCBN cutting tool (class CB7115) were examined. In general, the use of cutting fluid in turning process did not provide a better performance in relation to the dry cutting condition. Based on the obtained results, the turning of hardened materials is a viable alternative to the grinding process. [ABSTRACT FROM AUTHOR]

Titanium and its alloys are associated with low density and excellent strength/weight ratio, biocompatibility in surgical implants, high mechanical strength at high temperatures and excellent corrosion resistance. The Ti6Al4V alloy is applied in the aerospace, biomedical, chemical, naval and petrochemical industries. However, these alloys present problems during machining and are therefore considered materials of difficult machinability at high cutting speeds. This paper aims to analyse the wear mechanisms in cutting tools using cemented carbide (H13A) and synthetic polycrystalline diamond (PCD) in the high-speed turning of Ti6Al4V alloy, under the following cooling conditions: dry, jet and minimum quantity lubricant (MQL). To measure wear, a microscope was used to measure flank wear in the tools. Next, the images of these tools were obtained using scanning electron microscopy for the identification of the wear mechanisms. According to the results, the variation in the cutting parameters (cutting speed and feed rate), type of tool material, as well as the cooling conditions significantly affects the behaviour of the wear mechanisms. The wear mechanisms presented in the cutting tools are not the result of one single mechanism, but a combination of many mechanisms. Overall, the primary type of wear is flank wear and the mechanisms are abrasion, adhesion and attrition (adherence and drag). [ABSTRACT FROM AUTHOR]

In the grinding process, high temperatures occur due to the removal of materials and the residual stresses that are generated on the machined surface, thus affecting the mechanical behaviour of the material. The performance of this process depends largely on conditions of cooling to prevent overheat of the parts, which can interfere in surface integrity of the pieces. Residual stress is a key factor that influences the reliability, precision and life useful of final products. As such, 3D parameters are important in tribological studies, with many of them showing a strong correlation with surface operational performance. Therefore, this work aims to study, through the 3D surface parameter and residual stress, the surface behaviour of AISI 4340 hardened steel after plunge grinding, while using different cutting fluids (mix—50% based mineral oil and 50% soybean oil; synthetic cutting fluid and integral fluid—mineral oil-based lubricant), as well as the use of minimum quantity lubricant (MQL) technique. All the residual stresses found for in the grinding samples under all cooling conditions were compressive stresses, which are beneficial to machined components. The synthetic fluid had lower compressive stresses. In relation to the 3D parameters, integral and mixing fluids also obtained a better performance because these fluids allowed greater lubrication in comparison to other fluids used. The results showed that the type of cutting fluid influenced the surface integrity of the ground pieces. It was concluded that the results showed the use of the mix and MQL fluids as an alternative to the use of the integral and synthetic cutting fluids, thus contributing to an ecologically correct and sustainable manufacture. [ABSTRACT FROM AUTHOR]

To improve the physical and chemical properties of styrene-derived polymers, new polystyrene- co -acrylonitrile-co-butyl acrylate terpolymers were synthesized and subsequently sulfonated. Six terpolymer compositions were prepared under mass radical polymerization conditions and further sulfonated to promote proton conductivity. The terpolymers were characterized by Fourier Transformed Infrared Spectroscopy (FTIR), proton and carbon nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), Gel Permeation Chromatography (GPC), Thermomechanical Analysis (TMA), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Electrochemical Impedance Spectroscopy (EIS). All synthesized terpolymers have molecular weights over 160,000 g/mol and solubility on several organic solvents. Terpolymers also showed high thermal stability by TGA and comonomers reduced Tg transitions and complex moduli along BuA content; the complex moduli clearly increased with ACN content. Intermediate aliquots taken during the sulfonation reaction were characterized indicate that incorporation of the sulfonic group decreases the thermal stability from over 350 °C in terpolymers down to 150 °C after sulfonation. The degree of sulfonation analyzed by TGA ranged between 11.2 and 15.9% leading to a proton conductivity interval from 2.9 to 4.0 mS/cm. The results suggest a lateral crosslinking reaction through sulfone groups. The proton ion conductivity values obtained are similar to those of commercially available membranes described in the literature. • New composition of polystyrene-co-acrylonitrile-co-butyl acrylate terpolymers were prepared. • Sulfonated terpolymers were prepared and characterized. • Sulfonated terpolymers exhibits considerable thermic stability, a high hydration level and considerable ionic conductivity. • A strong tendency towards sulfone-type crosslinking reactions was identified during the sulfonation process. [ABSTRACT FROM AUTHOR]

The present study was designed to evaluate how environmental factors in a dry-summer subtropical climate in Terceira- Azores (situated in the North Atlantic Ocean: 38° 43' N 27° 12' W) can affect dairy cow (Holstein) fertility, as well as seasonal influence on in vitro oocytes maturation and embryos development. Impact of heat shock (HS) effects on in vitro oocyte's maturation and further embryo development after in vitro fertilization (IVF) was also evaluated. For such purpose the result of the first artificial insemination (AI) performed 60 to 90 days after calving of 6,300 cows were recorded for one year. In parallel, climatic data was obtained at different elevation points (n = 5) from 0 to 1,000 m and grazing points from 0 to 500 m, in Terceira island, and the temperature humidity index (THI) was calculated. For in vitro experiments, oocytes (n = 706) were collected weekly during all year, for meiotic maturation and IVF. Further, to evaluate HS effect, 891 oocytes were collected in the cold moths (December, January, February and March) and divided in three groups treated to HS for 24 h during in vitro maturation at: C (Control = 38.5°C), HS1 (39.5#176;C) and HS2 (40.5#176;C). Oocytes from each group were used for meiotic assessment and IVF. Cleavage, morula and blastocyst development were evaluated respectively on day 2, 6, and 9 after IVF. A negative correlation between cow's conception rate (CR) and THI in grazing points (-91.3%; p<0.001) was observed. Mean THI in warmer months (June, July, August and September) was 71.7±0.7 and the CR (40.2±1.5%) while in cold months THI was 62.8±0.2 and CR was 63.8±0.4%. A similar impact was obtained with in vitro results in which nuclear maturation rate (NMR) ranged from 78.4% (±8.0) to 44.3% (±8.1), while embryos development ranged from 53.8% (±5.8) to 36.3% (±3.3) in cold and warmer months respectively. In vitro HS results showed a significant decline (p<0.05) on NMR of oocytes for every 1#176;C rising temperature (78.4±8.0, 21.7±3.1 and 8.9±2.2, respectively for C, HS1, and HS2). Similar results were observed in cleavage rate and embryo development, showing a clear correlation (96.9 p<0.05) between NMR and embryo development with respect to temperatures. Results clearly demonstrated that, up to a THI of 70.6, a decrease in the CR occurs in first AI after calving; this impairment was confirmed with in vitro results. [ABSTRACT FROM AUTHOR]