Optimization of low temperature RF-magnetron sputtering of indium tin oxide films for solar cell applications

In this work we have studied the influence of argon working pressure, substrate temperature, low power plasma irradiation and partial pressure of hydrogen in the RF-magnetron sputtering of indium tin oxide (ITO) thin films on glass substrates. This work aims at identifying the best conditions to achieve good quality ITO films at low temperature for deposition on heat-sensitive substrates. Four sets of samples were prepared which were characterized by X-ray diffraction (XRD), Van der Pauw and transmittance measurements. It was found that structural, electrical and optical properties of the films depend strongly on the deposition parameters. ITO films with a thickness of ~300 nm, displaying a sheet resistance of 68 Ω/sq and average transmittance, in the visible range, of about 90% were produced performing the deposition at low pressure and at room temperature. However, further improvements in the sheet resistance up to a factor of 3 were obtained by decreasing a little more the argon working pressure or applying a low power plasma irradiation or adding a partial pressure of hydrogen to the working gas. Films produced at low working pressures are crystalline and have [222] preferential orientation. The conductivity and transmittance of these films are higher than those of films deposited at high pressures. The electrical resistivity of the ITO thin films decreased sharply either with low power plasma irradiation or the addition of a partial pressure of H2 to the working gas. All the films showed an average transmittance of over 80% in the visible range. Therefore, as a result of this work we established that the addition of a small partial pressure of H2 to the working gas during growth allowed us to achieve the main aim of depositing low resistivity ITO films at low substrate temperature suitable for the envisaged applications. At the same time, we concluded that this approach leads to a drastic reduction in the amount of target surface conditioning required every time a new target was installed because it turns the properties of the ITO films more independent of the target surface properties.publishe

Annealing of RF-magnetron sputtered SnS2 precursors as a new route for single phase SnS thin films

Tin sulphide thin films have been grown on soda-lime glass substrates through the annealing of RF-magnetron sputtered SnS2 precursors. Three different approaches to the annealing were compared and the resulting films thoroughly studied. One series of precursors was annealed in a tubular furnace directly exposed to a flux of sulphur vapour plus forming gas, N2 + 5%H2, and at a constant pressure of 500 mbar. The other two series of identical precursors were annealed in the same furnace but inside a graphite box with and without elemental sulphur evaporation again in the presence of N2 + 5%H2 and at the same pressure as for the sulphur flux experiments. Different maximum annealing temperatures for each set of samples, in the range of 300–570 C, were tested to study their effects on the properties of the final films. The resulting phases were structurally investigated by X-Ray Diffraction (XRD) and Raman spectroscopy. Annealing of SnS2 precursors in sulphur flux produced films where SnS2 was dominant for temperatures up to 480 C. Increasing the temperature to 530 C and 570 C led to films where the dominant phase became Sn2S3. Annealing of SnS2 precursors in a graphite box with sulphur vapour at temperatures in the range between 300 C and 480 C the films are multi-phase, containing Sn2S3, SnS2 and SnS. For high annealing temperatures of 530 C and 570 C the films have SnS as the dominant phase. Annealing of SnS2 precursors in a graphite box without sulphur vapour at 300 C and 360 C the films are essentially amorphous, at 420 C SnS2 is the dominant phase. For temperatures of 480 C and 530 C SnS is the dominant phase but also same residual SnS2 and Sn2S3 phases are observed. For annealing at 570 C, according to the XRD results the films appear to be single phase SnS. The composition was studied using energy dispersive spectroscopy being then correlated with the annealing temperature. Scanning electron microscopy studies revealed that the SnS films exhibit small grain structure and the film surface is rough. Optical measurements were performed, from which the band gap energies were estimated. These studies show that the direct absorption transitions of SnS are at 1.68 eV and 1.41 eV for annealing in graphite box with and without elemental sulphur evaporation, respectively. For the indirect transition the values varied from 1.49 eV to 1.37 eV. The results of this work show that the third approach is better suited to produce single phase SnS films. However, a finer tunning of the duration of the high temperature plateau of the annealing profile is required in order to eliminate the b-Sn top layer.info:eu-repo/semantics/publishedVersio

Enriquecimiento nutricional de aceites vegetales con ácidos grasos n-3 de cadena larga mediante interesterificación enzimática con una nueva lipasa vegetal

The aim of the present work was to produce vegetable oils enriched with long-chain n-3 fatty acids of nutraceutical interest, through an enzyme-catalyzed interesterification with a new lipase, from physic nut (Jatropha curcas L.). The Vegetable Lipase Powder (biocatalyst) called VLP, which has never been applied in functional foods, was obtained from the physic nut seed, and efficiently hydrolyzed the 95% of waste fish oil in 24 h. Urea precipitation was used to concentrate polyunsaturated fatty acids (PUFA) and was further interesterified with oils of different sources by means of enzymatic catalysis. After the interesterification reaction, which was also catalyzed by the VLP, the PUFA content in coconut oil increased almost ten-fold from 1.8% to 17.7%. In palm oil, the PUFA content increased two-fold from 10.5% to 21.8%, while in olive oil the level of PUFA increased from 8.6% to 21.3%. The mixture of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (3.7% to 3.9%) was incorporated into the triacylglycerol fraction of each of the coconut, palm and olive oils. Through the hydroesterification (hydrolysis followed by interesterification) all the interesterified vegetable oils tested presented sufficient EPA and DHA levels to satisfy the levels recommended for intake by human adults in one tablespoon.El objetivo del presente trabajo fue producir aceites vegetales enriquecidos con ácidos grasos n-3 de cadena larga de interés nutraceutico, por interesterificación catalizada mediante una nueva lipasa, una enzima de semilla de Jatropha curcas L. La lipasa vegetal en polvo (biocatalizador) llamada VLP, nunca ha sido aplicada en alimentos funcionales, se obtuvo mediante procedimientos físicos con semillas de nueces, e hidrolizó eficientemente el 95% de aceites de residuos de pescado en 24 h. La precipitación con urea se utilizó para concentrar los ácidos grasos poliinsaturados (PUFA) que fueron posteriormente interesterificados con aceites de diferentes fuentes mediante catálisis enzimática. Tras la reacción de interesterificación, que también fue catalizada por la VLP, el contenido de PUFA en el aceite de coco aumentó casi diez veces de 1,8% a 17,7%. En el aceite de palma, el contenido de PUFA aumentó dos veces desde 10,5% a 21,8%, mientras que en el aceite de oliva el nivel de PUFA incrementó de 8,6% a 21,3%. La mezcla de ácido eicosapentaenoico (EPA) y ácido docosahexaenoico (DHA) (3,7% a 3,9%) fué incorporada a la fracción de triacilgliceroles de cada uno de los aceites, coco, palma y oliva. Mediante hidroesterificación (hidrólisis seguido de interesterificación) todos los aceites vegetales interesterificados ensayados contienen en una cucharada suficientes niveles de EPA y DHA para cubrir los niveles recomendados de ingesta de humanos adultos

The antecedents of export performance of Brazilian small and medium-sized enterprises (SMEs): The non-linear effects of customer orientation

This article examines the determinants of customer orientation and the quadratic effects of customer orientation on export performance. The relationship between customer orientation and export performance has been assumed to have a linear relationship, neglecting the possibility of non-linear relationships. While most studies have been conducted in developed countries, we test our model in Brazil, an emerging market economy. The findings suggest that technology intensity and competitive intensity are key determinants in explaining success in an export market. Our findings also indicate that the relationship between customer orientation and export performance is quadratic (U-shaped) rather than linear. The implications of these findings are discussed

Desigualdades de renda na saúde bucal e no acesso aos serviços odontológicos na população Brasileira : pesquisa nacional de saúde, 2013

Despite the improvement in oral health conditions observed in the Brazilian population, there are still high social inequalities that must be monitored. To evaluate income inequality in oral hygiene practices, oral health status and the use of dental services in the adult and senior Brazilian population. Data from the National Health Survey conducted in 2013 (Pesquisa Nacional de Saúde – PNS 2013) were used for the population aged 18 years old or older. Inequalities were found among the income strata in most of the oral health indicators evaluated. The greatest inequalities were observed in the use of dental floss, in hygiene practices (PR = 2.85 in adults and PR = 2.45 in seniors), and in total tooth loss (PR = 6.74 in adults and PR = 2.24 in seniors) and difficulty in chewing (PR = 4.49 in adults and PR = 2.67 in seniors) among oral condition indicators. The magnitude of inequalities was high in both groups in most oral condition indicators. Income was a factor that persisted in limiting access to dental services, and even the lower income segments had high percentages that paid for dental consultations. Based on data from the first PNS, the findings of this study enabled the identification of oral health and dental care aspects more compromised by income differentials, thus, contributing to the planning of dental care in Brazil and to stimulate the monitoring of these disparities with data from future surveys222CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ817122/2015Apesar da melhora das condições de saúde bucal constatada na população brasileira, persistem elevadas desigualdades sociais que precisam ser monitoradas. Avaliar a desigualdade de renda nas práticas de higiene bucal, nas condições bucais e no uso de serviços odontológicos na população brasileira de adultos e idosos. Foram utilizados dados da Pesquisa Nacional de Saúde realizada em 2013 (PNS 2013) referentes à população de 18 anos ou mais. Detectaram-se desigualdades entre os estratos de renda na maioria dos indicadores de saúde bucal avaliados. As desigualdades de maior magnitude foram verificadas no uso de fio dental, nas práticas de higiene (RP = 2,85 nos adultos e RP = 2,45 nos idosos), e na perda de todos os dentes (RP = 6,74 nos adultos e RP = 2,24 nos idosos) e dificuldade de mastigar (RP = 4,49 nos adultos e RP = 2,67 nos idosos) entre os indicadores de condições bucais. Na maioria dos indicadores de condições bucais a magnitude das desigualdades foi elevada em ambos os grupos. A renda mostrou-se um fator que persiste limitando o acesso aos serviços odontológicos e, mesmo os segmentos de menor renda apresentaram elevados percentuais que pagam por consulta odontológica. Por meio dos dados da primeira PNS, os achados do estudo permitiram identificar aspectos de saúde e de atenção bucais mais comprometidos pelos diferenciais de renda, podendo, nesse sentido, contribuir para o planejamento da assistência odontológica no país e para estimular o monitoramento destas disparidades com dados das próximas pesquisa

Multi-target analysis of cytostatics in hospital effluents over a 9-month period

The consumption of cytostatics, pharmaceuticals prescribed in chemotherapy, is increasing every year and worldwide, along with the incidence of cancer. The presence and the temporal evolution of cytostatics in wastewaters from a Portuguese hospital center was evaluated through a 9-month sampling campaign, comprising a total of one hundred and twenty-nine samples, collected from May 2019 to February 2020. Eleven cytostatics out of thirteen pharmaceuticals were studied, including flutamide, mycophenolate mofetil and mycophenolic acid, which have never been monitored before. Target analytes were extracted and quantified by solid-phase extraction coupled to liquid-chromatography-tandem mass spectrometry analysis; the method was fully validated. All pharmaceuticals were detected in at least one sample, bicalutamide being the one found with higher frequency (detected in all samples), followed by mycophenolic acid, which was also the compound detected at higher concentrations (up to 5340 ± 211 ng/L). Etoposide, classified as carcinogenic to humans, was detected in 60% of the samples at concentrations up to 142 ± 15 ng/L. The risk from exposure to cytostatics was estimated for aquatic organisms living in receiving bodies. Cyclophosphamide, doxorubicin, etoposide, flutamide, megestrol and mycophenolic acid are suspected to induce risk. Long-term and synergic effects should not be neglected, even for the cytostatics for which no risk was estimated

Pristine Multi-walled carbon nanotubes for a rapid and efficient plasmid DNA clarification

Therapeutic approaches based on nucleic acids to modulate cell activity have recently gained attention. These molecules arise from complex biotechnological processes, requiring effective manufacturing strategies, high purity, and precise quality control to be used as biopharmaceuticals. One of the most critical and time-consuming steps for nucleic acids-based biotherapeutics manufacturing is their purification, mainly due to the complexity of the extracts. In this study, a simple, efficient, and reliable method to isolate and clarify plasmid DNA (pDNA) from complex samples is described. The method is based on the selective capture of RNA and other impurities, using pristine carbon nanotubes (CNTs). Multi-walled CNTs (MWCNTs) with different diameters were studied to determine their adsorption capacity and to address their ability to interact and distinguish between nucleic acids. The results revealed that MWCNTs preferentially interact with RNA and that smaller MWCNTs present a higher adsorption capacity, as expected by the higher specific surface area. Overall, this study showed that MWCNTs significantly reduce the levels of impurities, namely RNA, gDNA, and proteins, by approximately 83.6 % compared to their initial level, enabling the recovery of clarified pDNA in solution while maintaining its stability throughout the recovery process. This method facilitates the pre-purification of pDNA for therapeutic applications.publishe

PACCE: Perl Algorithm to Compute Continuum and Equivalent Widths

We present Perl Algorithm to Compute continuum and Equivalent Widths (pacce). We describe the methods used in the computations and the requirements for its usage. We compare the measurements made with pacce and "manual" ones made using iraf splot task. These tests show that for SSP models the equivalent widths strengths are very similar (differences <0.2A) for both measurements. In real stellar spectra, the correlation between both values is still very good, but with differences of up to 0.5A. pacce is also able to determine mean continuum and continuum at line center values, which are helpful in stellar population studies. In addition, it is also able to compute the uncertainties in the equivalent widths using photon statistics. The code is made available for the community through the web at http://www.if.ufrgs.br/~riffel/software.html.Comment: 8 pages, 5 figures, accepted by Astrophysics and Space Scienc