Resumen: Desde hace una década el Programa Arqueológico Huanchaco viene investigando diversos sitios en la bahía de Huanchaco, Región La Libertad, costa norte del Perú, en los que han sido recuperados un centenar de objetos metálicos asociados a diversos periodos culturales. Para este estudio se tomó una muestra de cinco objetos de metal que fueron analizados por las técnicas de microscopía óptica, electrónica y radiografías digitales. Estas piezas estuvieron asociadas a contextos estratigráficos controlados con fechados AMS que los vinculan a rangos temporales absolutos entre el 400-200 AC y el 200-500 DC. Los resultados muestran que la técnica de cobre dorado por eliminación fue empleada por los orfebres entre el 400-200 AC, lo que indicaría que su utilización es más temprana de lo que se conocía a la fecha. En este mismo estudio se muestra cómo el uso de esta técnica es continuada por sociedades posteriores hasta el 450/500 DC. Luego, orfebres de la sociedad moche (450/500 - 800/850 DC) comienzan a introducir nuevas técnicas orfebres de dorado observables en algunos objetos utilizados en Huanchaco. En suma, las muestras analizadas son reducidas, pero por provenir de contextos controlados resultan de gran importancia.

Abstract: During the last ten years, the Huanchaco Archaeological Program has investigated many sites on the Huanchaco coast, La Libertad Region, North Coast of Peru, where a hundred metallic objects associated with various cultural periods have been recovered. For this paper, we have chosen five metal artifacts associated with secure contexts and with AMS dates, which were analyzed using optical and electronic microscopy as well as digital X-rays. The absolute temporal frames for these artifacts are between 400 and 200 cal. BC (late Early Horizon) and AD 200-500. Our results indicate that between 400 and 200 cal. BC, the gilded depletion copper technique was in use, which according to our knowledge is the earliest reported for the Andean region. This study shows how the use of this technique is continued by later societies until AD 450/500. After this period, goldsmiths of the Moche society (AD 450/500 - 800/850) began to introduce new goldsmithing techniques, observable in some objects used in Huanchaco. In sum, the samples are scarce, but due to their origins from controlled contexts, they are of utmost importance.

Tucumã (Astrocaryum aculeatum) pulp presents a large number of secondary metabolites that can mediate the synthesis of metallic nanoparticles through a greener and more sustainable synthetic route than traditional ones. This study investigated the production of silver nanoparticles (AgNPs) mediated by aqueous extracts of tucumã pulp assessing different parameters, such as temperature, concentration of extract, and pH values of the reaction media. The alkaline reaction media produced the most intense and well-defined bands around 400 nm in the electronic spectra, indicating the formation of AgNPs in the three concentrations of tucumã pulp evaluated. The increase in the temperature of the reaction media also enhanced the surface plasmon resonance band of AgNPs but it increased the polydispersivity of produced nanoparticles according to the dynamic light scattering (DLS) and transmission electron microscopy (TEM) data. Zeta potential results indicated moderate stability of the AgNPs (close to -30 mV). Antimicrobial assessment of the colloidal metal particles indicated microbicide activity against the Gram-negative Escherichia coli bacterium.

ABSTRACT Wastewater treatment system by activated sludge, the purification of the organic matter by specific heterogeneous microorganisms, occurs in the presence of oxygen in aeration tanks. The analysis of the microfauna present in the sludge is an important indicator of the performance and efficiency of the activated sludge system. Considering this importance, the objective of this work was to identify the microorganisms which are part of the microfauna present in the aeration tank of the effluent treatment plant of a soybean processing industry in the state of Mato Grosso, evaluating the biological activity of the sludge and the efficiency of the process. Protozoa and bacteria were identified through electronic microscopy and physical-chemical analyses such as pH, dissolved oxygen, nitrogen, phosphorus, BOD, COD, suspended solids, and SVI. During the study, it was possible to identify bacteria related to flake formation, organic matter degradation, nitrification and denitrification, and also microorganisms such as thecamoebas, micrometazoa, fixed ciliates and ciliates free natantes, characterizing the process with good purification and the structure of the sludge flakes between ideal and filamentous bulking with a high sludge age. The identification of the microfauna present was efficient as a bioindicator of the treatment system condition with removal of BOD and COD of 59.75 and 67.09%, respectively.

RESUMO No sistema de tratamento de efluentes por lodo ativado ocorre a depuração da matéria orgânica por microrganismos heterogêneos específicos, em presença de oxigênio nos tanques de aeração. A análise da microfauna presente no lodo é um importante indicador do desempenho e da eficiência do sistema de lodos ativados. Diante disso, o objetivo do trabalho foi identificar os microrganismos que compõem a microfauna do tanque de aeração da estação de tratamento de efluentes de uma indústria alimentícia processadora de soja do estado de Mato Grosso, avaliando a atividade biológica do lodo e a eficiência do processo. Foi realizada a identificação dos protozoários e das bactérias pela microscopia eletrônica, e fizeram-se as análises físico-químicas de pH, oxigênio dissolvido, nitrogênio, fósforo, demanda bioquímica de oxigênio, demanda química de oxigênio, sólidos suspensos e índice volumétrico de lodo. Durante o estudo, foi possível observar as bactérias relacionadas na formação do floco, na degradação da matéria orgânica, na nitrificação e na desnitrificação, e também microrganismos como as tecamebas, micrometazoários, ciliados fixos e ciliados livres natantes, que caracterizam o processo com alta idade de lodo, boa depuração e alta concentração de oxigênio dissolvido. A identificação da microfauna presente mostrou-se eficiente como bioindicadora da condição do sistema de tratamento, observando-se que o sistema da indústria se apresentou com boa depuração e com remoção de demanda bioquímica de oxigênio e demanda química de oxigênio, de 59,75 e 67,09%, respectivamente.

ABSTRACT Currently, the presence of spurious microwave radiation is increasing in the environment, which has caused concern due to possible health problems in living beings and electromagnetic interference in electronic systems. To control this problem, studies in the materials area are taking place, aiming to attenuate the spurious radiation and meet requirements of good performance in broadband, low cost and low weight. The present work aimed to study Cu and Ni nanometric films with thicknesses of 65 and 200 nm, deposited on polyethylene terephthalate substrate by magnetron sputtering. Scanning electron microscopy with a field emission gun (FEG-SEM) showed that the films produced have different morphological textures, due to the parameters used in the sputtering process and also the free energy of metals. Impedance spectroscopy measurements showed that the films have low conductivity values, due to the metallic oxides formed on the film surfaces, confirmed by X-ray diffraction, and also to the presence of defects. Electromagnetic characterization (8.2 – 12.4 GHz) showed that the Cu and Ni thin films had low performance, except the Ni_200 nm film, which showed a total shielding efficiency of about 30% in broadband. This result is promising considering the nanometric thickness of the Ni film.

The experimental activities for undergraduate chemistry students play an important role to develop skills and expertise in that science thus, the practice-experimental classes are so important to achieve this purpose. This work deals with a demonstrative experience for dye separation from food coloring sample using liquid column chromatography. Beyond the experimental practice and the facility in visualizing the separation, this demonstration shows how a simple experiment involving alternative and easy access materials can promote a meaningful learning once it is possible to handle the acquired data, trace and analyze the results themselves, thus developing skills rather than the operational procedure. This proposal could be implemented in initial chemistry classes in Brazilian universities. Sea and river sands were used as stationary phases and aqueous ethanolic solutions were used as mobile phases. A food coloring (a mixture of 3 dyes) was chosen as sample to be studied. Chromatographic separation was followed by spectrophotometric measurements. A set of analyses were carried out to discuss the solubility of the food coloring, granulometric studies of the stationary phases used and electronic microscopy images of the sands studied here. As alternative materials were used in this work, a chromatographic column was also constructed with low-cost materials.

Abstract: During the last ten years, the Huanchaco Archaeological Program has investigated many sites on the Huanchaco coast, La Libertad Region, North Coast of Peru, where a hundred metallic objects associated with various cultural periods have been recovered. For this paper, we have chosen five metal artifacts associated with secure contexts and with AMS dates, which were analyzed using optical and electronic microscopy as well as digital X-rays. The absolute temporal frames for these artifacts are between 400 and 200 cal. BC (late Early Horizon) and AD 200-500. Our results indicate that between 400 and 200 cal. BC, the gilded depletion copper technique was in use, which according to our knowledge is the earliest reported for the Andean region. This study shows how the use of this technique is continued by later societies until AD 450/500. After this period, goldsmiths of the Moche society (AD 450/500 - 800/850) began to introduce new goldsmithing techniques, observable in some objects used in Huanchaco. In sum, the samples are scarce, but due to their origins from controlled contexts, they are of utmost importance.

Resumen: Desde hace una década el Programa Arqueológico Huanchaco viene investigando diversos sitios en la bahía de Huanchaco, Región La Libertad, costa norte del Perú, en los que han sido recuperados un centenar de objetos metálicos asociados a diversos periodos culturales. Para este estudio se tomó una muestra de cinco objetos de metal que fueron analizados por las técnicas de microscopía óptica, electrónica y radiografías digitales. Estas piezas estuvieron asociadas a contextos estratigráficos controlados con fechados AMS que los vinculan a rangos temporales absolutos entre el 400-200 AC y el 200-500 DC. Los resultados muestran que la técnica de cobre dorado por eliminación fue empleada por los orfebres entre el 400-200 AC, lo que indicaría que su utilización es más temprana de lo que se conocía a la fecha. En este mismo estudio se muestra cómo el uso de esta técnica es continuada por sociedades posteriores hasta el 450/500 DC. Luego, orfebres de la sociedad moche (450/500 - 800/850 DC) comienzan a introducir nuevas técnicas orfebres de dorado observables en algunos objetos utilizados en Huanchaco. En suma, las muestras analizadas son reducidas, pero por provenir de contextos controlados resultan de gran importancia.

We investigate the structural, optical, thermal-optical, and electronic properties of TiNx thin films utilizing a variety of experimental techniques, including spectroscopic ellipsometry, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, thermal lens spectroscopy, and UV-VIS spectroscopy. Our experimental results indicate a remarkable metallic character in the TiNx thin films deposited under lower N2 flow during treatment, as well as an increase in reflectance in the infrared region and thermal diffusivity as the partial N2 flow is reduced, which is consistent with previous experimental studies. The microscopic origin of these trends is explained in terms of the atomic structure of the system, where Ti atoms contribute free carriers that interact with IR radiation and N atoms create imperfections in the lattice, causing greater scattering of phonons, respectively. The experimental results also indicate that the roughness of the films produced with a lower N2 partial flow was lower than that of the films with a higher N2 partial flow. To explain the deviation of optical properties from the ideal case, surface oxidation is also investigated. This facilitates the coating of smarting windows with TiNx thin films. structural thermaloptical, thermaloptical thermal-optical techniques ellipsometry spectroscopy microscopy UVVIS UV VIS treatment reduced studies system lattice phonons respectively case investigated

With increasing life expectancy, revision surgeries have become more frequent in implanted people. This is due to the biological and biomechanical incompatibility that generates, among others, problems such as stress shielding. This works aims to analyze the influence of the hot rolling process (HR sample) on the microstructure and, consequently, the properties of β-Ti multiprincipal alloys: Ti-27Nb-39Zr (39Zr), Ti-30Nb-50Zr (50Zr), and Ti-20Nb-30Zr-13Ta (30Zr) (wt. %.) (equimassic and with high content of β-stabilizer elements). All samples were subjected to characterization through X-ray diffraction (XRD) to determine the phases present, and optical microscopy (OM) and scanning electronic microscopy (SEM) were realized to characterize the microstructure and confirm the phases obtained through XRD. Before hot rolling, only the β phase was identified, but in the HR condition, the α and β phases were identified. Consequently, it did not observe significant changes in microhardness for all alloys, while the elastic modulus was observed with a reduction of 23% for 39Zr, 46% for 40Zr, and 13% for 30Zr. The hot rolling processing was confirmed to be a helpful route to reduce the elastic modulus for β Ti multiprincipal alloys opening perspectives for applying such alloys as metallic implant materials.

ABSTRACT ABS resins have wide application in the market, mainly in the manufacture of household appliances, telephones, automotive industry and others, and need to be processed by extrusion for the manufacture of products. The variables used in the process of extrusion of polymers have a direct influence on their mechanical properties. The objective of this study was to evaluate the different speeds of the extruder screw (15, 30, 45 and 60 rpm) on the mechanical properties of raw ABS after the extrusion process. Izod impact resistance and tensile tests, were also performed. The fractures of the samples tested by Izod impact were observed via optical microscopy, scanning electronic microscopy (SEM), and roughness was measured. Calorimetric tests (DSC) and thermogravimetry (TGA), as well as melt flow index (MFI), were also performed. The most significant results were observed for the extruder screw speed of 60 rpm. For the impact test, a reduction in impact energy of approximately 3% was observed, with the same result for tensile resistance. However, an increase in the value of the elastic modulus and the MFI was observed due to the increase in the degree of crystallinity, which was caused by the higher shear of the polymer mass in the screw of the extrusion equipment. Additionally, an atypical case occurred for the ABS polymer in the highest rotation, since it was the polymer that suffered the greatest shear in the polymer chains due to the degradation of the butadiene phase.

Abstract Background Fibroblast-like synoviocytes (FLS) play a prominent role in rheumatoid synovitis and degradation of the extracellular matrix through the production of inflammatory cytokines and metalloproteinases (MMPs). Since animal models are frequently used for elucidating the disease mechanism and therapeutic development, it is relevant to study the ultrastructural characteristics and functional responses in human and mouse FLS. The objective of the study was to analyze ultrastructural characteristics, Interleukin-6 (IL-6) and Metalloproteinase-3 (MMP-3) production and the activation of intracellular pathways in Fibroblast like synoviocytes (FLS) cultures obtained from patients with rheumatoid arthritis (RA) and from mice with collagen-induced arthritis (CIA). Methods FLSs were obtained from RA patients (RA-FLSs) (n = 8) and mice with CIA (CIA-FLSs) (n = 4). Morphology was assessed by transmission and scanning electron microscopy. IL-6 and MMP-3 production was measured by ELISA, and activation of intracellular signaling pathways (NF-κB and MAPK: p-ERK1/2, p-P38 and p-JNK) was measured by Western blotting in cultures of RA-FLSs and CIA-FLSs stimulated with tumor necrosis factor-alpha (TNF-α) and IL-1β. Results RA-FLS and CIA-FLS cultures exhibited rich cytoplasm, rough endoplasmic reticula and prominent and well- developed Golgi complexes. Transmission electron microscopy demonstrated the presence of lamellar bodies, which are cytoplasmic structures related to surfactant production, in FLSs from both sources. Increased levels of pinocytosis and numbers of pinocytotic vesicles were observed in RA-FLSs (p < 0.05). Basal production of MMP-3 and IL-6 was present in RA-FLSs and CIA-FLSs. Regarding the production of MMP-3 and IL-6 and the activation of signaling pathways, the present study demonstrated a lower response to IL-1β by CIA-FLSs than by RA-FLSs. Conclusion This study provides a comprehensive understanding of the biology of RA-FLS and CIA-FLS. The differences and similarities in ultrastructural morphology and important inflammatory cytokines shown, contribute to future in vitro studies using RA-FLS and CIA-FLS, in addition, they indicate that the adoption of CIA-FLS for studies should take careful and be well designed, since they do not completely resemble human diseases.

Resumen Nanocellulose (NC) was obtained from palm oil rachis by combination of a chemical explosion method and mechanical rupture, which was functionalized with cholic acid (AC) and trietoxy(octyl)silane (TEOS) as functionalizing agents for determining the As3+ ion adsorption capacity from water. The nanocellulose functionalized it was characterized by infrared spectroscopy, thermal gravimetric analysis, scanning electronic microscopy and transmission electronic microscopy. Arsenic was measured by visible absorption according to molybdenum blue method. Nanofiber of cellulose was obtained with size than 19 – 24 nm, with which a functionalization of 25,96 % was achieved for NCAC and 20,50 % for NC-TEOS. The adsorption tests showed a 63,6 % removal of As3+ ion from the water using NC-AC and 22,6 % using NC-TEOS as adsorbents respectively, with which NC-AC showed a potential adsorption capacity material for ion As3+ from water.

Abstract The purpose of this article is to present the results of using the video to promote peer and self – assessment in the first two oral English courses at University of Costa Rica, Paraiso Campus, Bachelor in English Teaching. In 2017 and 2018 students recorded three videos for each course in which they talked about some of the topics that were suggested by the instructor and were closely related to the course contents. In class, as group work, they used a guideline prepared by the instructor to review their peers’ videos. They focused on the presenter’s delivery, grammar, and pronunciation as well as in the content of the recording. During the peer evaluation activity, learners received written as well as oral responses from their partners. In the self – evaluation stage of the activity, they answered a questionnaire in which they indicated the number of times they recorded their videos before handing them to the instructor as well as their perception of their own performance as well as what they considered they needed to improve about it. The idea behind asking them to write the number of times they had to record the video was to know if they had self – evaluated. The fourth video in each course asked pupils to value how their language competence had evolved, during the first semester and during the whole year respectively. Results show that incorporating the video in the language class was an effective strategy to promote peer and self-assessment.

Resumen Se obtuvo nanocelulosa de raquis de palma africana (NC) por medio de la combinación del método químico de explosión y ruptura mecánica. La NC fue funcionalizada con ácido cólico (NC-AC) y con trietoxi(octil)silano (NC-TEOS) para determinar su capacidad de adsorción de iones As3+ del agua. Las nanocelulosas funcionalizadas fueron caracterizadas por espectroscopia infrarroja, análisis termogravimétrico, microscopía electrónica de barrido y microscopía electrónica de transmisión. El arsénico fue medido por absorción visible por el método de azul de molibdeno.[1] La NC obtenida fue fibrilar con un tamaño de 19 – 24 nm con la cual se consiguió una funcionalización de 25,96 % para la NC-AC y de 20,50 % para la NC-TEOS. Las pruebas de adsorción mostraron una remoción del 63,6 % de los iones As3+ del agua utilizando NC-AC y de 22,6 % utilizando NC-TEOS como adsorbentes respectivamente, colocando la NC-AC como un potencial material de adsorción de iones As3+ del agua

Abstract Nanocellulose (NC) was obtained from palm oil rachis by combination of a chemical explosion method and mechanical rupture, which was functionalized with cholic acid (AC) and trietoxy(octyl)silane (TEOS) as functionalizing agents for determining the As3+ ion adsorption capacity from water. The nanocellulose functionalized it was characterized by infrared spectroscopy, thermal gravimetric analysis, scanning electronic microscopy and transmission electronic microscopy. Arsenic was measured by visible absorption according to molybdenum blue method. Nanofiber of cellulose was obtained with size than 19 – 24 nm, with which a functionalization of 25,96 % was achieved for NCAC and 20,50 % for NC-TEOS. The adsorption tests showed a 63,6 % removal of As3+ ion from the water using NC-AC and 22,6 % using NC-TEOS as adsorbents respectively, with which NC-AC showed a potential adsorption capacity material for ion As3+ from water.

Abstract Nanoparticles are materials that measure from 1 to 100 nm of length. Currently, the antimicrobial property of silver nanoparticles is used by industries for the manufacture of beauty products and medicines. Nanoparticles can be synthesized from plants, algae or microorganisms, and they can also be obtained from combustion products. In this study, extracts of rosemary leaves (Rosmarinus officinalis L.) were used for the synthesis of silver nanoparticles (NPs-Ag) in order to produce an antimicrobial compound to be used as a fruit preservative. NPs-Ag were characterized qualitatively and quantitatively by phytochemical analysis and UV-VIS spectroscopy, showing an absorption in the range of 389-418 nm, which corresponds to their surface plasmon resonance. Furthermore, Scanning Electronic Microscopy was used to determine the size and morphology of the NPs-Ag, observing a spherical shape of 10 nm of diameter. Two bacterial strains were used in the antimicrobial tests, the Gram-negative (Escherichia coli) and the Gram-positive (Staphylococcus aureus) to verify the antimicrobial activity of the NPs-Ag. For E. coli, a better antibacterial activity was obtained with an inhibition halo of 3.21 mm. Subsequently, the NPs-Ag were used in apples to determine their use as a preservative, using beeswax smeared on the surface of the fruit as control, observing that synthesized NPs-Ag prolonged the maturation time of the fruits.

Resumen Las nanopartículas son materiales que pueden llegar a medir entre 1 a 100 nm de longitud, y en la actualidad la propiedad antimicrobiana de las nanopartículas de plata es aprovechada por las industrias para la fabricación de productos de belleza y medicamentos. Las nanopartículas pueden ser sintetizadas a partir de plantas, algas o microorganismos, y también pueden ser obtenidas como productos de combustión. En este estudio se utilizaron extractos de las hojas de romero (Rosmarinus officinalis L.) para la síntesis de nanopartículas de plata (NPs-Ag) con la finalidad de producir un compuesto antimicrobiano para usarse como conservante de frutas. Las NPs-Ag se caracterizaron cualitativa y cuantitativamente mediante análisis fitoquímicos y espectroscopia UV-VIS, presentando una absorción en el rango de 389-418 nm, que corresponde a la resonancia de su plasmón superficial. Además, se empleó la microscopía electrónica de barrido para determinar el tamaño y morfología de las NPs-Ag, observándose una forma esférica de 10 nm de diámetro. Se emplearon dos cepas bacterianas en los ensayos antimicrobianos realizados, la gramnegativa (Escherichia coli) y la grampositiva (Staphylococcus aureus) para comprobar la actividad antimicrobiana de las NPs-Ag. Para E. coli se obtuvo una mejor actividad antibacteriana con un halo de inhibición de 3,21 mm. Posteriormente se usaron las NPs-Ag en manzanas para determinar su uso como conservante, usando la cera de abeja como control untada en la superficie de las frutas, observándose que las nanopartículas sintetizadas alargaron el tiempo de maduración de las frutas.

High-yield ZnO spheroidal nanoparticles with an average diameter around 23 nm (≈ 25% frequency) and 30 nm (≈ 28% frequency) were obtained by controlled semicontinuous precipitation at low temperatures. This synthesis was obtained from hydrozincite (Zn5(CO3)2(OH)6) as primary nanoparticles. The Zn5(CO3)2(OH)6 nanoparticles were synthesized by hydrolysis of Zn(NO3)2 in aqueous solution of (NH4)2CO3 and later, the precipitation becomes. Two temperatures of 60 and 70 °C in combination with three times of reaction were tested; followed by calcination of the precipitate at 400 °C. This range of sizes of nanoparticles is comparable with those obtained by other methods reported in the literature, such as microemulsions, however, here the advantage was not using solvents or surfactants. The ZnO nanoparticles were characterized by energy dispersive X-ray spectroscopy coupled to a scanning electron microscopy (SEM-EDS), transmission electronic microscopy (TEM), and X-ray diffraction. The antibacterial activity of the films against Gram-positive (S. aureus) and Gram-negative (E. coli.) bacteria was investigated using the disc diffusion method. The best results were found in the inhibition zone for Gram-positive bacteria, when the concentration of ZnO NPs incorporated was 3 mg disc-1.