Pretreatment of cotton spinning residues for optimal enzymatic hydrolysis: a case study using green solvents

ABSTRACT: The effectiveness of imidazole and ionic liquid pretreatments for the conversion of cotton spinning residues (dirty cotton residue - DCR and cotton filter powder - CFP) into soluble sugars was investigated. DCR was pretreated with imidazole using temperatures and reaction times that were arranged in a 2(2) factorial design and pretreatment performance was evaluated by enzymatic hydrolysis. High glucan to glucose and xylan to xylose yields (78.0 and 94.9 mol %) were obtained from the solids produced at 140 degrees C and 2h (center point), which provided delignification levels of 45.5% (w.v(-1)). The same pretreatment condition was applied to CFP yielding only 16.0% (w.v(-1)) of delignification, but 75.8 mol % of glucan and 95.7 mol % of xylan were converted as their corresponding monomeric sugars after enzymatic hydrolysis. Both pretreated materials were subjected to a central composite design to find the best enzymatic hydrolysis conditions regarding substrate total solids (TS) and enzyme loading. More than 40 g.L-1 glucose was obtained from both pretreated materials at 13.7% w.w(-1) TS and 20 FPU.g(-1) glucan after 96 h of hydrolysis. Ionic liquid pretreatment of the same cotton spinning residues showed moderate delignification levels, accompanied by a change in biomass crystallinity from cellulose 1 beta to cellulose II. This turned to be very important to improve enzymatic hydrolysis yields. Therefore, biomass delignification and crystallinity confirmed to be key factors governing the enzymatic saccharification of cotton spinning residues.info:eu-repo/semantics/publishedVersio

Coordinate noncommutativity in strong non-uniform magnetic fields

Noncommuting spatial coordinates are studied in the context of a charged particle moving in a strong non-uniform magnetic field. We derive a relation involving the commutators of the coordinates, which generalizes the one realized in a strong constant magnetic field. As an application, we discuss the noncommutativity in the magnetic field present in a magnetic mirror.Comment: 4 page

THE SOUTH ATLANTIC OCEAN IN THE DISCOURSES AT THE UN: A CONTENT ANALYSIS ON THE REGIONAL NATURE OF THE OCEANIC SPACE (1986-2015)

This research is related to studies about the building of regions, understood here as cognitive constructions linked to political projects and manifested through speeches. Studies in this same theoretical line have already been developed about the South Atlantic Ocean in the past, but always limited to the perspective of Brazilian foreign policy as a potential region-building agent of the South Atlantic region, ignoring the response of other states to the project. Seeking to remedy this gap, the research applied the method of quantitative content analysis to 106 speeches containing citations to the South Atlantic, issued at the General Assembly of the United Nations by states bordered by the South Atlantic. The content of the texts was categorized into five analytical dimensions: (1) geographical delimitation; (2) international or transnational political relations in the territory in question that are described by their actors as regional dynamics; (3) identity factors; (4) nominal citation to other actors and; (5) specific issues treated as relevant to the space in question. The results suggest that ZOPACAS is, in fact, a region-building project for the South Atlantic Ocean, whose period of greatest strength took place between 1986 and 1994, losing steam until 1998 and falling into ostracism since then. Although the revival of the initiative in 2007 signaled a potential renaissance of a South-Atlantic region-building project, it seems that the common oceanic space continues to be mostly interpreted as a mere area of interaction between the regions of South America and West Africa.Keywords: South Atlantic; ZOPACAS; Region-BuildingA presente pesquisa se insere junto a estudos sobre construção de regiões, entendidas aqui como construções cognitivas atreladas a projetos políticos e manifestadas por meio de discursos. Trabalhos nessa mesma linha teórica já foram desenvolvidos sobre o Atlântico Sul no passado, mas sempre limitados à perspectiva da política externa brasileira enquanto potencial agente construtor da região sul-atlântica, ignorando a resposta dos demais Estados ao projeto. Procurando sanar essa lacuna, a pesquisa aplicou o método da análise de conteúdo quantitativa a 106 discursos que contivessem citações ao Atlântico Sul, proferidos na Assembleia Geral das Nações Unidas por Estados banhados pelo oceano em questão. O conteúdo dos textos foi categorizado dentro de cinco dimensões de análise: (1) delimitação geográfica; (2) relações políticas internacionais ou transnacionais no território em questão que sejam descritas por seus atores como dinâmicas regionais; (3) fatores identitários; (4) citação nominal a outros atores e; (5) questões pontuais tratadas como relevantes para o espaço em questão. Os resultados sugerem que a ZOPACAS de fato se trata de um projeto de construção regional para o Atlântico Sul, cujo período de maior força se deu entre 1986 e 1994, perdendo fôlego até 1998 e caindo no ostracismo desde então. Embora a retomada da iniciativa em 2007 tenha sinalizado um potencial renascimento de um projeto de construção regional sul-atlântico, tudo indica que o espaço oceânico comum continua sendo interpretado majoritariamente como um mero espaço de interação entre as regiões da América do Sul e da África Ocidental

Insight into the high-pressure CO2 pre-treatment of sugarcane bagasse for a delivery of upgradable sugars

ABSTRACT: This work provides an insight into sugarcane bagasse pre-treatment carried out with greener and more sustainable CO2/H2O system. Temperatures and residence times at a fixed initial CO2 pressure were studied to verify their effects on pre-treatment efficiency with regard to the chemical composition of both water-soluble and water-insoluble fractions as well as to the susceptibility of the latter to enzymatic hydrolysis at high total solids. Also, trends in enzymatic hydrolysis were analysed in function of biomass crystallinity. This work provides an integrated approach in the analysis of upgradable sugars that are released as a result of pre-treatment and enzymatic hydrolysis. At optimal pre-treatment conditions, 17.2 g.L-1 sugars were released in the water-soluble fraction mainly as pentoses in monomeric and oligomeric forms. The enzymatic hydrolysis of solids produced at these pre-treatment conditions gave 76.8 g.L-1 glucose in the substrate hydrolysate. The overall sugar yield delivered in both pre-treatment and enzymatic hydrolysis was 73,9 mol%. These results were compared to the chemical effect of hydrothermal and/or physico-chemical effects of N-2-aided hydrothermal processes and showed that the greener processing of biomass pre-treatment with CO2 is advantageous for the integrated valorisation of industrial residues and delivery of upgradable sugars within the biorefinery concept.info:eu-repo/semantics/publishedVersio

Rhodolith bed structure along a depth gradient on the northern coast of bahia state, brazil

O objetivo deste estudo foi determinar a estrutura de um banco de rodolitos ao longo de um gradiente de profundidade na plataforma em frente à cidade de Salvador, nordeste brasileiro. Foram analisadas as dimensões, a forma e composição das algas calcárias dos rodolitos, bem como a vitalidade, densidade e flora associada ao banco, em três profundidades: 5, 15 e 25 m. As amostras foram obtidas por meio de mergulho autônomo no verão de 2007. Cinco espécies de algas calcárias formadoras de rodolito foram identificadas: Sporolithon episporum, Lithothamnion brasiliense, Lithothamnion superpositum, Mesophyllum erubescens e Lithophyllum sp. A forma de crescimento incrustante e a forma esférica foram predominantes em todas as profundidades. Houve uma redução da dimensão e vitalidade dos rodolitos e um aumento da densidade com a profundidade. Cinqüenta e seis espécies de macroalgas foram encontradas como flora associada aos rodolitos. A profundidade mais rasa apresentou os maiores valores de biomassa e número de espécies de macroalgas. Esses resultados, associados com outras descrições recentes de bancos de rodolitos, indicam que o padrão estrutural desses bancos no Brasil, ao longo de gradientes de profundidade, pode estar relacionado a uma combinação da extensão e da inclinação da plataforma continental.The aim of this study was to determine the structure of a rhodolith bed along a depth gradient of 5 to 25 m in the shelf in front of Salvador City, a region of northeastern Brazil. The dimensions, morphology and coralline algae composition of the rhodoliths were analyzed, as well as the vitality, density, and associated flora of the bed at three depths: 5, 15 and 25 m. Samples were obtained by SCUBA divers in summer 2007. Five rhodolith-forming taxa were identified: Sporolithon episporum, Lithothamnion brasiliense, Lithothamnion superpositum, Mesophyllum erubescens, and Lithophyllum sp. The encrusting growth form and the spherical shape were predominant at all depths. Rhodolith dimensions and vitality decreased and the density increased from the shallow to the deepest zones. Fifty-six macroalgal species were found as rhodolith-associated flora. The shallower depth presented higher values for macroalgal biomass and number of species. These results associated with other recent rhodolith bed descriptions indicate that the pattern of Brazilian rhodolith bed structure along depth gradients may be related to a combination of the extent and slope of the continental shelf

Exploring the Elastic Properties and Fracture Patterns of Me-Graphene Monolayers and Nanotubes through Reactive Molecular Dynamics Simulations

Me-graphene (MeG) is a novel two-dimensional (2D) carbon allotrope. Due to its attractive electronic and structural properties, it is important to study the mechanical behavior of MeG in its monolayer and nanotube topologies. In this work, we conducted fully atomistic reactive molecular dynamics simulations using the Tersoff force field to investigate their mechanical properties and fracture patterns. Our results indicate that Young's modulus of MeG monolayers is about 414 GPa and in the range of 421-483 GPa for the nanotubes investigated here. MeG monolayers and MeGNTs directly undergo from elastic to complete fracture under critical strain without a plastic regime.Comment: 10 pages, 01 table, and 05 figure

Preventing Farnesylation of the Dynein Adaptor Spindly Contributes to the Mitotic Defects Caused by Farnesyltransferase Inhibitors

The clinical interest in farnesyltransferase inhibitors (FTIs) makes it important to understand how these compounds affect cellular processes involving farnesylated proteins. Mitotic abnormalities observed after treatment with FTIs have so far been attributed to defects in the farnesylation of the outer kinetochore proteins CENP-E and CENP-F, which are involved in chromosome congression and spindle assembly checkpoint signaling. Here we identify the cytoplasmic dynein adaptor Spindly as an additional component of the outer kinetochore that is modified by farnesyltransferase (FTase). We show that farnesylation of Spindly is essential for its localization, and thus for the proper localization of dynein and its cofactor dynactin, to prometaphase kinetochores and that Spindly kinetochore recruitment is more severely affected by FTase inhibition than kinetochore recruitment of CENP-E and CENP-F. Molecular replacement experiments show that both Spindly and CENP-E farnesylation are required for efficient chromosome congression. The identification of Spindly as a new mitotic substrate of FTase provides insight into the causes of the mitotic phenotypes observed with FTase inhibitors

Whole-genome enrichment provides deep insights into Vibrio cholerae metagenome from an African river

The detection and typing of Vibrio cholerae in natural aquatic environments encounter major methodological challenges related to the fact that the bacterium is often present in environmental matrices at very low abundance in nonculturable state. This study applied, for the first time to our knowledge, a whole-genome enrichment (WGE) and next generation sequencing (NGS) approach for direct genotyping and metagenomic analysis of low abundant V. cholerae DNA (<50 genome unit/L) from natural water collected in the Morogoro river (Tanzania). The protocol is based on the use of biotinylated RNA baits for target enrichment of V. cholerae metagenomic DNA via hybridization. An enriched V. cholerae metagenome library was generated and sequenced on a Illumina MiSeq platform. Up to 1.8X107 bp (4.5x mean read depth) were found to map against V. cholerae reference genome sequences representing an increase of about 2500 times in target DNA coverage compared to theoretical calculations of performance for shotgun metagenomics. Analysis of metagenomic data revealed the presence of several V. cholerae virulence and virulence associated genes in river water including major virulence regions (e.g. CTX prophage and Vibrio pathogenicity island-1) and genetic markers of epidemic strains (e.g. O1-antigen biosynthesis gene cluster) that were not detectable by standard culture and molecular techniques. Overall, besides providing a powerful tool for direct genotyping of V. cholerae in complex environmental matrices this study provides a \u201cproof of concept\u201d on the methodological gap that might currently preclude a more comprehensive understanding of toxigenic V. cholerae emergence from natural aquatic environments

Inhibitory action of Lippia gracilis Schauer essential oil on pathogenic bacteria and its effects as a growth promoter on quail

Aim of the study: To examine the in vitro sensitivity of Salmonella sp. and Escherichia coli strains to the microbial activity of Lippia gracilis Schauer essential oil (LGSEO) and to determine the optimal level of LGSEO as a growth promoter in diets for Japanese quail up to 35 days of age.Area of study: São Cristovão, Sergipe, Brazil.Material and methods: A total of 504 female Japanese quails (Coturnix coturnix japonica) at an initial average body weights of 6.80±0.10 g was allotted to one of six treatments (0, 100, 200, 300, 400 mg/kg of LGSEO and a diet containing 500 mg/kg of bacitracin methylene disalicylate) in 7 replicates, using 12 birds per experimental unit.Main results: In the age period of 21 to 35 days, feed intake declined linearly (p=0.04) and feed efficiency improved (p<0.01), whereas no changes were observed in production performance (p>0.05). The estimated (p=0.01) maximum relative weights of proventriculus and pancreas were obtained at the LGSEO inclusion levels of 196.5 and 251 mg/kg, respectively. Inclusion of 100 to 300 mg/kg of LGSEO in the diet reduced the total Salmonella sp. bacterial count.Research highlights: The use of 196.5 mg/kg of LGSEO in the diet of Japanese quail improved production performance and organ development and demonstrated potential antimicrobial capacity against Salmonella sp. bacteria. Due its pharmacological composition, LGSEO can potentially substitute to antimicrobials, because contains thymol and carvacrol as main active constituents