Redox mechanisms of conversion of Cr(VI) to Cr(III) by graphene oxide-polymer composite.

Alternative methods of aqueous chromium removal have been of great research interest in recent years as Cr (VI) is a highly toxic compound causing severe human health effects. To achieve better removal of Cr (VI), it is essential to understand the chemical reactions that lead to the successful removal of Cr species from the solution. Recent studies have demonstrated that graphene oxide (GO) based polymer beads cannot only adsorb Cr (VI) via electrostatic attractions but also reduce it to Cr (III), which is a much less toxic form of chromium. This conversion and the functional groups involved in this conversion, until now, were not elucidated. In the present study, we employed X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy to investigate the conversion pathway of Cr (VI) to Cr (III) in graphene-based polymer beads. The results showed that alcoholic groups are converted to carboxylic groups while reducing Cr (VI) to Cr (III). The inclusion of GO in the polymer beads dramatically increased the potential of Cr (VI) uptake and conversion to Cr (III), indicating polymers and nanomaterials containing alcohol groups can remove and convert chromium in water. Other functional groups present in the polymer bead play an important role in adsorption but are not involved in the conversion of Cr (VI) to Cr (III).

Polypropylene meshes coated with chitosan/polyethylene glycol for the reconstruction of the abdominal wall: an experimental study in rats / Telas de polipropileno revestidas com o filme de quitosana/polietilenoglicol para a reconstrução da parede abdominal: estudo experimental em ratos

The aim of this study was to characterize the tissue reactions triggered by the polypropylene mesh coated with chitosan and polyethylene glycol film, and if it's able to prevent the formation of peritoneal adhesions. Defects in the abdominal wall of rats were induced and polypropylene meshes coated with chitosan/polyethylene glycol (CPEG group, n= 12) and uncoated (PP control group, n= 12) were implanted. On the fourth and forty-fifth postoperative day the formation of adhesion and the tissue reaction to the biomaterial was evaluated through histological and histochemical analysis. The area (P= 0.01) and severity (P= 0.002) of the adhesion was significatively less in the CPEG group. On the fourth day the foreign body reaction was less intense in CPEG group (P= 0.018) and the production of collagen fibers was more intense in this group (P= 0.041). The tissue reactions caused by the biomaterials were similar on the 45th day, with the exception of the high organization of collagen fibers in the CPEG group. The CPEG meshes did not fully prevent the formation of adhesions, but minimized the severity of the process. The foreign body reaction promoted by polypropylene meshes coated with CPEG is less intense than that triggered by uncoated polypropylene meshes.(AU)

O objetivo deste estudo foi caracterizar as reações tissulares desencadeadas pela tela de polipropileno revestida com o filme de quitosana e polietilenoglicol e verificar se ela é capaz de prevenir a formação de aderências peritoneais. Um defeito na parede abdominal dos ratos foi realizado, e as telas de polipropileno revestidas com quitosana/polietilenoglicol (grupo CPEG, n= 12) e sem revestimento (grupo controle PP, n= 12) foram implantadas. No quarto e no 45º dia pós-operatório, avaliou-se a formação de aderências e a reação tecidual ao biomaterial por análise histológica e histoquímica. A área (P= 0,01) e a severidade (P= 0,002) da aderência peritoneal foram significativamente menores no grupo CPEG no 45º dia. No quarto dia, observou-se que a reação do corpo estranho foi menor no grupo CPEG (P= 0,018), e a produção de fibras de colágeno mais intensa (P= 0,041). As reações tissulares causadas pelos biomateriais implantados foram semelhantes no 45º dia, com exceção da melhor organização das fibras colágenas no grupo CPEG. As telas CPEG não impediram completamente a formação de aderências, porém minimizaram a gravidade do processo. A reação de corpo estranho promovida por telas de polipropileno revestidas com CPEG é menos intensa do que a desencadeada por telas de polipropileno não revestidas.(AU)

Molecular identification and microbiological evaluation of isolates from equipments and food contact surfaces in a hospital Food and Nutrition Unit / Avaliação microbiológica e identificação molecular de isolados de equipamentos e superfícies de contato com alimentos em um hospital Unidade de Alimentação e Nutrição

Abstract The hygienic and sanitary control in Food and Nutrition Units (FNU) is considered a standard procedure to produce adequate meals and reduce the risk of foodborne diseases and hospital infections. This study aimed to evaluate the isolation and identification of bacteria from equipment and food contact surfaces in a hospital FNU as well as to evaluate the sanitary condition. Likewise, it was analyzed the adhesion of the microorganisms on polyethylene cutting boards. The presence of aerobic mesophilic microorganisms, yeasts, molds, coagulase-positive staphylococci, coliform and fecal coliform, and Escherichia coli were analyzed on eating tables, countertop surfaces and cutting boards used for meat or vegetable handling, and equipment such as microwaves and refrigerators. The molecular identification it was done by 16S rRNA gene sequencing. The adhesion of the microorganisms (biofilm formation) on meat and vegetable cutting boards was also evaluated by scanning electron microscopy. The results showed high numbers of all microorganisms, except for E. coli , which was not observed in the samples. The molecular analysis identified species of the Enterobacteriaceae family and species of the Pseudomonadaceae family. Scanning electron microscopy analyses revealed bacterial adhesion on the cutting board surfaces. The results obtained in this study indicated that the hygienic conditions of surfaces like plastic cutting boards and equipment in this hospital FNU were inadequate. The achievement and application of standard operating procedures could positively help in the standardization of sanitary control, reducing the microbial contamination and providing a safe food to hospitalized patients.

Resumo O controle higiênico e sanitário nas Unidades de Alimentação e Nutrição (UAN) é considerado um procedimento padrão para produzir refeições adequadas e reduzir o risco de doenças transmitidas pelos alimentos e infecções hospitalares. Este estudo teve como objetivo isolar e identificar bactérias de equipamentos e superfícies de contato com alimentos em uma UAN hospitalar, bem como avaliar a condição sanitária. Do mesmo modo, analisou-se a adesão dos micro-organismos em tábuas de corte de polietileno. A presença de micro-organismos aeróbios mesófilos, leveduras, fungos, Sthapylococcus coagulase-positivos, coliformes, coliformes fecais e Escherichia coli foi analisadas na superfície de mesas do refeitório, superfícies de bancada e tábuas de corte usadas para manuseio de carne ou vegetais e, em equipamentos como micro-ondas e refrigeradores. A identificação molecular foi feita pelo sequenciamento do gene 16S rRNA. A adesão dos micro-organismos (formação de biofilmes) em tábuas de corte de carne e de vegetais também foi avaliada por microscopia eletrônica de varredura. Os resultados mostraram elevada contagem para todos os micro-organismos analisados, exceto para E. coli, a qual não foi observada nas amostras. A análise molecular identificou espécies da família Enterobacteriaceae e Pseudomonadaceae. A análise de microscopia eletrônica de varredura revelaram adesão bacteriana nas superfícies das placsa de corte. Os resultados obtidos neste estudo indicaram que as condições higiênicas das superfícies e de equipamentos nesta UAN hospitalar estavam inadequadas. A aplicação de procedimentos operacionais padrão poderia auxiliar positivamente na padronização do controle higiênico-sanitário, reduzindo a contaminação microbiana e fornecendo um alimento seguro para pacientes hospitalizados.

Molecular identification and microbiological evaluation of isolates from equipments and food contact surfaces in a hospital Food and Nutrition Unit.

The hygienic and sanitary control in Food and Nutrition Units (FNU) is considered a standard procedure to produce adequate meals and reduce the risk of foodborne diseases and hospital infections. This study aimed to evaluate the isolation and identification of bacteria from equipment and food contact surfaces in a hospital FNU as well as to evaluate the sanitary condition. Likewise, it was analyzed the adhesion of the microorganisms on polyethylene cutting boards. The presence of aerobic mesophilic microorganisms, yeasts, molds, coagulase-positive staphylococci, coliform and fecal coliform, and Escherichia coli were analyzed on eating tables, countertop surfaces and cutting boards used for meat or vegetable handling, and equipment such as microwaves and refrigerators. The molecular identification it was done by 16S rRNA gene sequencing. The adhesion of the microorganisms (biofilm formation) on meat and vegetable cutting boards was also evaluated by scanning electron microscopy. The results showed high numbers of all microorganisms, except for E. coli , which was not observed in the samples. The molecular analysis identified species of the Enterobacteriaceae family and species of the Pseudomonadaceae family. Scanning electron microscopy analyses revealed bacterial adhesion on the cutting board surfaces. The results obtained in this study indicated that the hygienic conditions of surfaces like plastic cutting boards and equipment in this hospital FNU were inadequate. The achievement and application of standard operating procedures could positively help in the standardization of sanitary control, reducing the microbial contamination and providing a safe food to hospitalized patients.

Tratamento de feridas excisionais de coelhos com extrato de barbatimão associado a células mononucleares autólogas da medula óssea / Treatment of excisional wound in rabbits with barbatiman extracts associated with autologous bone marrow mononuclear cells

Objetivou-se com este estudo avaliar o processo de cicatrização de feridas de coelhos tratadas com extrato de barbatimão (S. adstringens) associado a células mononucleares autólogas da medula óssea (CMMO). Utilizaram-se 20 coelhos, distribuídos em quatro grupos: B, extrato de barbatimão; CB, CMMO com extrato de barbatimão; CS, CMMO com solução fisiológica; S, solução fisiológica. Foi avaliada a presença de crosta, hiperemia, secreção, hemorragia, reepitelização, área da ferida e tempo de cicatrização. No terceiro, sétimo, 14º e 21º dias pós-operatório, realizou-se a biópsia das feridas e avaliaram-se os indicadores dos processos de inflamação e de reparo, com destaque para o colágeno, na coloração picrosírius, bem como de proliferação celular, na coloração AgNOR. Houve maior deposição de fibras colágenas nos grupos B e CB (P=0,00003) e formação de crostas mais espessas no sétimo dia, com fibras colágenas mais organizadas no 21º dia. Conclui-se que o barbatimão estimula a produção de fibras colágenas e promove a formação de crostas mais espessas sobre a ferida na fase inicial da cicatrização e, na fase de remodelação, favorece a orientação das fibras colágenas. Além disso, a associação desse fitoterápico com CMMO não estimula a cicatrização de feridas.(AU)

This study aimed to evaluate the healing process of wounds of rabbits in response to treatment with barbatiman extract (S. adstringens) associated with autologous mononuclear bone marrow cells (BM-MNC). We used 20 rabbits, divided into four groups: B, 10% barbatiman extract with 9.48% of total tannins; CB, BM-MNC with barbatiman extract; CS, BM-MNC with NaCl 0.9% solution; S, NaCl 0.9% solution. Clinical evaluation was performed by observing the presence of crust, redness, discharge, bleeding, re-epithelialization, the wound area and healing time in days. In the third, seventh, 14th and 21st postoperative days wounds were biopsied for microscopic evaluation of inflammation and repair process indicators, especially collagen, in picrosirius staining, and cell proliferation, in AgNOR staining. There was a greater deposition of collagen fibers in groups B and CB (p=0.00003) on the seventh day and formation of thicker crusts, and more organized collagen fibers on the 21st day in these groups. In conclusion, in the initial phase of healing, barbatiman extract stimulates the production of collagen fibers and promotes the formation of more exuberant crusts on the wounds and remodeling phase favors the orientation of collagen fibers, but when combined with BMMC does not stimulate wound healing in rabbits.(AU)

On the antibacterial mechanism of graphene oxide (GO) Langmuir-Blodgett films.

The Langmuir-Blodgett (LB) technique was used to immobilize flat graphene oxide (GO) sheets on a PET substrate to ascertain as to whether the edges of GO play an integral part in its antimicrobial mechanism. The observed antibacterial activity suggests that contact with the edges is not a fundamental part of the mechanism.

Diversity of hydrocarbon-degrading Klebsiella strains isolated from hydrocarbon-contaminated estuaries.

AIMS: To investigate the diversity and the catabolic capacity of oil-degrading Klebsiella strains isolated from hydrocarbon-contaminated sediments in Santos-São Vicente estuary systems in Brazil. METHODS AND RESULTS: Klebsiella strains obtained from the estuary were characterized using 16S rRNA gene sequencing and BOX-PCR patterns, testing their catabolic capacity to degrade toluene, xylene, naphthalene and nonane, and identifying the catabolic genes present in the oil-degrading strains. Results show that Klebsiella strains were widespread in the estuary. Twenty-one isolates from the Klebsiella genus were obtained; 14 had unique BOX patterns and were further investigated. Among four distinct catabolic genes tested (todC1, ndoB, xylE and alkB1), only the todC1 gene could be amplified in two Klebsiella strains. The biodegradation assay showed that most of the strains had the ability to degrade all of the tested hydrocarbons; however, the strains displayed different efficiencies. CONCLUSIONS: The oil-degrading Klebsiella isolates obtained from the estuary were closely related to Klebsiella pneumoniae and Klebsiella ornithinolytica. The isolates demonstrated a substantial degree of catabolic plasticity for hydrocarbon degradation. SIGNIFICANCE AND IMPACT OF THE STUDY: The results of this study show that several strains from the Klebsiella genus are able to degrade diverse hydrocarbon compounds. These findings indicate that Klebsiella spp. can be an important part of the oil-degrading microbial community in estuarine areas exposed to sewage.

Viability and sporulating capability of Coelomycetes preserved under a range of different storage regimes.

The viability and sporulating capability of 45 Coelomycetes strains were evaluated. Strain subcultures were maintained under mineral oil, in soil and on agar slant for different periods of time lasting as long as 50 years, 39 years and 2 years, respectively. Of the 34 strains preserved under mineral oil, 20 maintained their viability but lost the sporulating capability with exception of one strain of Pestalotiopsis guepinii. Of the 16 strains also preserved in soil only one was viable and it was not able to sporulate. All 12 endophytic strains, 11 preserved on agar slant and one under mineral oil remained viable; however, the strain preserved under mineral oil lost its sporulating capability, while the strains on agar slant were only able to sporulate after culturing on sterilized alfalfa twigs. The results demonstrate that routine monitoring, and the use of different preservation methods, specially with the addition of sterilized plant tissue on the culture media for promoting conidiomata formation, is necessary for the success of the Coelomycetes long-term preservation.