Manganese pigmented anodized copper as solar selective absorber

The study concerns the optical and structural properties of layers obtained by a new efficient surface treatment totally free of chromium species. The process is made up of an anodic oxidation of copper in an alkaline solution followed by an alkaline potassium permanganate dipping post-treatment. Coatings, obtained at the lab and pilot scales, are stable up to 220 °C in air and vacuum, present low emissivity (0.14 at 70 °C) and high solar absorptivity (0.96), i.e. a suitable thermal efficiency (0.84 at 70 °C)

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Estudio comparativo entre la deshidratación convencional y en microondas del kimbombó.

This study was conducted to evaluate different pre-treatments and dehydration methods on the quality of okra. No significant differences were found among pretreatments and dehydration methods for the chemical composition of dehydrated okra samples. Dipping in 0.1 % sodium metabisulphite solution at room temperature and immersion in 0.1 % sodium metabisulphite solution at 92-95 °C improved the retention of ascorbic acid of okra samples after dehydration by either conventional or microwave oven. Also, the reduced dehydration time required for microwave dehydration produced far less destruction of ascorbic acid. The highest rehydration ratio was found in unwashed okra sample and dehydrated by microwave after immersion in 0.1 % sodium metabisulphite solution at 92-95 °C. Dehydrated okra samples by sun drying and conventional oven had lower retention percentages of total chlorophyll and carotenoids than those of dehydrated okra samples by microwave oven. The general appearance and colour scores of dehydrated okra samples by microwave were significantly different from those of conventionally dehydrated or sun dried okra samples.Este estudio se ha realizado para evaluar los diferentes pretratamientos y métodos de deshidratación en la calidad del kimbombó. No se encontraron diferencias significativas entre ellos respecto a la composición química de las muestras de kimbombó deshidratadas. La inmersión en solución de metabisulfito sódico al 0.1 % a temperatura ambiente y la inmersión en solución de metabisulfito sódico al 0.1 % a 92-95 °C mejoraron la retención de ácido ascórbico de las muestras de kimbombó después de la deshidratación tanto utilizando el homo convencional como el horno microondas. Además el menor tiempo necesario para la deshidratación usando el horno microondas produjo menos destrucción de ácido ascórbico. La mayor relación de rehidratación fue encontrada en muestras de kimbombó no tratadas o deshidratadas usando horno microondas tras inmersión en metabisulfito sódico al 0.1 % y 92-95 °C. Las muestras de kimbombó deshidratadas por secado al sol y homo convencional tuvieron menores porcentajes de retención de clorofilas totales y carotenoides que las de muestras de kimbombó deshidratadas usando homo microondas. La apariencia general y la calidad del color de las muestras de kimbombó deshidratadas mediante horno microondas fueron significativamente diferentes de aquéllas deshidratadas mediante homo convencional o secadas al sol

Seaweeds agarophytes and associated epiphytic bacteria along Alexandria coastline, Egypt, with emphasis on the evaluation and extraction of agar and agarose

A survey of seaweeds along Alexandria coastline was carried out to choose a suitable agarophyte for extraction and evaluation of the agar and agarose substances, in addition to estimate and identify the epiphytic bacteria associated with these seaweeds which are capable of secreting package of hydrolytic enzymes and hence degrading algal cell walls successfully. A total of 13 algal samples were collected during spring 2012. There were 2 Rhodophytes species; Gelidium crinale and Pterocladiella capillacea, which can be exploited for agar and agarose production. Nine dominant bacterial isolates were associated with the different algal samples; they were identified at genus level as; Alcaligenes sp., Bordetella sp., Acinetobacter sp., Pseudomonas sp.1, Pseudomonas sp.2, Pseudomonas sp.3, Flavobacterium sp., Vibrio sp. and Vigribacillus sp. The most superior species able to secrete a package of degrading enzymes was Vigribacillus sp. that was isolated from P. capillacea harvested from Western Harbor. The total carbohydrate, lipid and protein contents were determined in both P. capillacea and its agar, and in Oxoid agar (a reference commercial material). Some metals (copper, cadmium, lead, zinc, nickel, chrome, ferrous, manganese and arsenic) were also estimated in the 3 mentioned samples. The gel strength, gelling temperature and melting temperature besides the clarity and viscosity of extracted and Oxoid agars showed different patterns. The sulphate content of the extracted agar was slightly higher than that of Oxoid agar, while the pyruvate content showed inverse pattern. The extracted agar FTIR spectrum indicated methylated group, which proved that the agar extracted from P. capillacea is a highly methylated polysaccharide resulting in high gellation.Se realizó un estudio de algas marinas en la costa de Alejandría para seleccionar una agarófita adecuada para la extracción y evaluación de las sustancias de agar y agarosa, además de estimar e identificar las bacterias epifitas asociadas con estas algas capaces de secretar paquetes de enzimas hidrolíticas degradantes de paredes celulares de algas. Un total de 13 muestras de algas se recolectaron durante primavera del 2012. Del total se obtuvieron 2 especies de Rhodophyta; Gelidium crinale y Pterocladiella capillacea, las cuales pueden ser explotadas para la producción de agar y agarosa. Se encontraron un total de 9 géneros de aislados bacterianos dominantes asociados con las diferentes muestras de algas. Estos fueron identificados como; Alcaligenes sp., Bordetella sp., Acinetobacter sp., Pseudomonas sp.1, Pseudomonas sp.2, Pseudomonas sp.3, Flavobacterium sp., Vibrio sp. y Vigribacillus sp. La especie con mayor capacidad de secretar un paquete de enzimas degradantes fue Vigribacillus sp. que fue aislada de P. capillacea cosechado en Western Harbor. Los hidratos de carbono, lípidos y proteínas totales se determinaron tanto en P. capillacea, como en el agar extraido, y agar Oxoid (material comercial de referencia). Además se estimaron algunos metales (cobre, cadmio, plomo, zinc, níquel, cromo, hierro, manganeso y arsénico) en las 3 muestras mencionadas. La resistencia de gel, temperatura de gelificación y fusión, además de la claridad y viscosidad de los extractos y agares Oxoid mostraron diferentes patrones. El contenido de sulfato del agar extraído fue ligeramente mayor que la de agar Oxoid, mientras que el contenido de piruvato mostró patrón inverso. El espectro FTIR del agar extraído indicó grupo metilado, lo que sugiere que el agar extraído de P. capillacea es un polisacárido altamente metilado por tanto de una alta gelificación