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This page shows you the most recent publications within this specialty of the MedWorm directory.

Valorization of agroindustrial solid residues and residues from biofuel production chains by thermochemical conversion: a review, citing Brazil as a case study
Besides high industrial development, Brazil is also an agribusiness country. Each year about 330 million metrics tons (Mg) of biomass residues are generated, requiring tremendous effort to develop biomass systems in which production, conversion and utilization of bio-based products are carried out efficiently and under environmentally sustainable conditions. For the production of biofuels, organic chemicals and materials, it is envisaged to follow a biorefinery model which includes modern and proven green chemical technologies such as bioprocessing, pyrolysis, gasification, Fischer-Tropsch synthesis and other catalytic pro...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Optimization of the precipitation of clavulanic acid from fermented broth using t-octylamine as intermediate
This work describes the use of clavulanic acid (CA) precipitation as the final step in the process of purification of CA from fermentation broth as an alternative to conventional methods employed traditionally. The purpose of this study was to use a stable intermediate (t-octylamine) between the conversion of CA to its salt form (potassium clavulanate), thereby enabling the resulting intermediate (amine salt of clavulanic acid) to improve the purification process and maintain the stability of the resulting potassium clavulanate. To this end, response surface methodology was employed to optimize the precipitation step. For ...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Recombinant Erwinia carotovora l-asparaginase II production in Escherichia coli fed-batch cultures
Asparaginases are the cornerstone therapy of many successful combination regimens for the treatment of acute lymphoblastic leukemia (ALL), the most common malignancy in children and adolescents. The aim of this work was to produce recombinant Erwinia carotovora L-asparaginase II in Escherichia coli fed-batch cultures. Using a robust fed-batch technique with pre-determined exponential feeding rates, our bioreactor culture system yielded 30.7 grams of dry cell weight and 0.9 grams of soluble rErAII protein per liter of culture broth. The homogeneous rErAII activity was determined by isothermal titration calorimetry (ITC). Th...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Production of clavulanic acid and cephamycin C by Streptomyces clavuligerus under different fed-batch conditions
The effect of carbon source and feeding conditions on the production of clavulanic acid (CA) and cephamycin C (CephC) by Streptomyces clavuligerus was investigated. In fed-batch experiments performed with glycerol feeding, production of CA exceeded that of CephC, and reached 1022 mg.L-1. Highest CephC production (566.5 mg.L-1) was obtained in fed-batch cultivation with glycerol feeding. In fed-batch experiments performed with starch feeding, the production of CephC was in general higher than that of CA. A dissociation index (DI) was used to identify feeding conditions that favored production of CephC relative to CA. In all...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Immobilized Lactobacillus acidophilus produced from whey and alginate
An analysis was made of the use of whey fermentation by Lactobacillus acidophilus LA-5 for encapsulated probiotic bacteria cell production. Fermentation was done in a 2-liter Biostat B Fermentor at 28±1 ºC without air supply and agitation maintained at 200 rpm. Different processing conditions were studied using Center Composite Design applied to Surface Response Methodology. Maximum cell yield (2.7 x10(10) NMP/mL for 36 hours) was achieved with 30.85 g/L of lactose, a pH value of 6.45 and 1.04 g/L of inoculum. Cell growth was evaluated using reconstituted and fresh whey after 144 hours of fermentation in pre-optimized co...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Spirulina sp. LEB-18 culture using effluent from the anaerobic digestion
The carbon source is the most expensive nutrient for Spirulina production; effluents from anaerobic digestion contain this nutrient in the form of HCO3-. The aim of this study was to assess the growth kinetics, composition and fatty acid profile of Spirulina sp. LEB-18 grown in standard Zarrouk medium (NaHCO3 16.8 g L-1) and in Zarrouk medium replaced with 20% (v/v) effluent with reduced concentrations of NaHCO3 (5.3 and 2.8 g L-1). The use of effluent and lower concentrations of HCO3 was found to be an alternative to reduce the costs of Spirulina production, because there were no significant differences in growth paramete...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Evaluation of wavelength selection methods for 2D fluorescence spectra applied to bioprocesses characterization
In biotechnological processes, the productivity and costs depend strongly on the control of the operating conditions. For this reason, sensors that allow the monitoring of variables of interest become quite important. 2D fluorescence spectroscopy is one promising option among those that are being applied for this purpose. In the present work, three methods were evaluated to select the best excitation/emission wavelength pairs of 2D fluorescence spectra to infer product, substrate and cellular concentrations throughout a fermentation using a multiple linear chemometric model: Exhaustive Search (ES), Stepwise Regression and ...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

The behaviour of an anaerobic baffled reactor (ABR) as the first stage in the biological treatment of hog farming effluents
This present paper reports a study of the efficiency of an anaerobic Baffled Reactor (ABR) composed of three chambers working as the first stage of a biological treatment system for swine wastewater, over a period of 116 days. The average value of the volumetric organic loading rate (VOLR) was 17.8 kgCODtotal m-3 d-1, the biological organic loading rates (BOLR) based on total and filtered COD influents of 14381 mg L-1 and 3610 mg L-1, respectively, were: 1.3 kgCODtotal kgTVS d-1 and 0.98 kgCODfiltered kgTVS d-1, respectively, and the hydraulic loading rate (HLR) was about 1.4 m³ m-3 d-1. The average removal efficiency for...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Heat transfer to immiscible liquid mixtures in a spiral plate heat exchanger
This work presents new predictive correlations for heat transfer to immiscible liquid-liquid mixtures in a spiral plate heat exchanger. Liquid-liquid heat transfer studies were carried out in spiral plate heat exchangers for the water-octane, water-kerosene, and water-dodecane systems. For each composition of the mixture, the mass flow rate of the cold fluid was varied, keeping that of the hot fluid and the fluid inlet temperatures constant. Two-phase cold flow rates were in the laminar range, while the hot fluid flow was turbulent. Calculations of the LMTD (log mean temperature difference) correction factor showed that th...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Verification and validation in CFD for a free-surface gas-liquid flow in channels
This work deals with experimental and numerical studies of a 3-D transient free-surface two-phase flow in a bench-scale channel flow. The aim was to determine how well the homogeneous model can predict the fluid dynamics behavior and to validate the model. The model was validated with experimental data acquired for two hydrodynamic situations. The mathematical model was based on the mass conservation equations for liquid and gas phases and on the momentum conservation equation for the mixture, assuming interpenetrating, continuum and homogeneous hypotheses. Turbulence has been considered for the mixture through the standar...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Effect of drying temperature on the nutritional and antioxidant qualities of cumari peppers from Pará (Capsicum chinense Jacqui)
This study evaluated the proximate components, concentration of total polyphenols, antioxidant activity, and capsaicin and dihydrocapsaicin in the Cumari chili pepper from Pará, Brazil (Capsicum chinense Jacqui) both fresh and after subjected to three different drying temperatures. The results showed that the contents of ash and vitamin C for the dried pepper differed significantly (P
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Modification of PSf membrane nanostructure using different fabrication parameters and investigation of the CO2 separation properties of PDMS-coated PSf composite membranes
The effects of preparation parameters on the performance and morphology of polydimethylsiloxane/ polysulfone (PDMS/PSf) membranes were investigated. The PDMS layer is mainly used for sealing the defects of the PSf selective layer. The membrane morphologies were characterized by using scanning electron microscopy (SEM). The CO2/CH4 separation performance of membranes was studied by a pure gas permeation experimental set up. According to the SEM results, decreasing the water/N,N-dimethylacetamide (DMAc) ratio as the coagulation medium from pure water to mixture of 90 vol.% DMAc and 10 vol.% water resulted in complete disappe...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Parametric study of hydrogen production from ethanol steam reforming in a membrane microreactor
Microreactors are miniaturized chemical reaction systems, which contain reaction channels with characteristic dimensions in the range of 10-500 µm. One possible application for microreactors is the conversion of ethanol to hydrogen used in fuel cells to generate electricity. In this paper a rigorous isothermal, steady-state two-dimensional model was developed to simulate the behavior of a membrane microreactor based on the hydrogen yield from ethanol steam reforming. Furthermore, this membrane microreactor is compared to a membraneless microreactor. A potential advantage of the membrane microreactor is the fact that both ...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) nanoparticles prepared by a miniemulsion/solvent evaporation technique: effect of phbv molar mass and concentration
Miniemulsification and emulsion/solvent evaporation techniques were combined to produce poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanoparticles. Those nanoparticles were prepared with different PHBV molar masses and PHBV concentrations to verify their effect on the final particle size. Nanoparticles with an average diameter of 133 nm were obtained when a low molar mass (Mw = 44,350 g/mol) polymer was used. On the other hand, when high molar mass PHBV (Mw = 369,900 g/mol) was used under the same operational conditions, nanoparticles with a 300 nm average diameter and a broader particle size distribution were forme...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Synthesis and properties of collagen-g-poly(sodium acrylate-co-2-hydroxyethylacrylate) superabsorbent hydrogels
Novel biopolymer-based superabsorbent hydrogels were prepared by grafting crosslinked poly(acrylic acid-co-2-hydroxyethyl acrylate) (PAA-co-PHEA) chains onto collagen backbones through a free radical polymerization method. The graft copolymerization reaction was carried out in a homogeneous medium and in the presence of ammonium persulfate (APS) as initiator and N,N '-methylene bisacrylamide (MBA) as crosslinker. A proposed mechanism for collagen-g-(PAA-co-PHEA) formation was suggested and the hydrogel structure was confirmed using FTIR spectroscopy and TGA thermal analysis. Moreover, the morphology of the samples was exam...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Up-gradation of MoO3 and separation of copper, iron, zinc from roasted molybdenum ore by a leaching process
The present research paper deals with the oxidation process of molybdenum ore. The main target of the present study is the up-gradation of MoO3 from roasted molybdenum ore by a leaching process without waste generation. The most important application of hydrometallurgical processing is the leaching process of the ore and it is the primary process to make pure metal from ore. The present investigations optimize the following experimental parameters to improve the concentration of MoO3 as well as the separation of copper, iron and zinc in roasted molybdenum ore: effect of acid concentration, temperature, pulp density and lea...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

Effects of gas types and models on optimized gas fuelling station reservoir's pressure
There are similar algorithms and infrastructure for storing gas fuels at CNG (Compressed Natural Gas) and CHG (Compressed Hydrogen Gas) fuelling stations. In these stations, the fuels are usually stored in the cascade storage system to utilize the stations more efficiently. The cascade storage system generally divides into three reservoirs, commonly termed low, medium and high-pressure reservoirs. The pressures within these reservoirs have huge effects on performance of the stations. In the current study, based on the laws of thermodynamics, conservation of mass and real/ideal gas assumptions, a theoretical analysis has be...
Source: Brazilian Journal of Chemical Engineering - May 16, 2013 Category: Chemistry Source Type: research

A finite-size scaling study of wedge filling transitions in the 3D Ising model
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50207D, PaperJose Manuel Romero-Enrique, Alvaro Rodriguez-Rivas, Luis F. Rull, Andrew O. ParryWe analyse theoretically and by computer simulations the finite-size scaling at the critical wedge filling transition for the 3D Ising model.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Jose Manuel Romero-Enrique Source Type: research

Polymers in 2-D confinement
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50644D, PaperHenrich Frielinghaus, Xiuli Frielinghaus, Nino Ruocco, Jurgen Allgaier, Wim Pyckhout-Hintzen, Dieter Richter2-D confined polymer chains were observed using small angle neutron scattering.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Henrich Frielinghaus Source Type: research

Growth of ring-shaped microtubule assemblies through stepwise active self-organisation
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50704A, PaperDaisuke Inoue, Arif Md. Rashedul Kabir, Hiroyuki Mayama, Jian Ping Gong, Kazuki Sada, Akira KakugoStepwise active self-organisation of microtubules offers a means to prolong the growth of the ring-shaped microtubule assemblies.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Daisuke Inoue Source Type: research

Submicron hybrid vesicles consisting of polymer-lipid and polymer-cholesterol blends
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50733E, PaperSvenja Winzen, Max Bernhardt, David Schaeffel, Amelie Koch, Michael Kappl, Kaloian Koynov, Katharina Landfester, Anja KroegerThe formation of hybrid polymer-lipid and polymer-cholesterol submicron unilamellar vesicles is investigated by a combination of analytical techniques with respect to membrane packing and nanomechanical properties.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Svenja Winzen Source Type: research

Yield stress, thixotropy and shear banding in a dilute aqueous suspension of few layer graphene oxide platelets
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50708D, PaperK. S. Vasu, Rema Krishnaswamy, S. Sampath, A. K. SoodWe demonstrate that percolated network of non-aggregating GO platelets (aspect ratio [similar] 5000) form a thixotropic yield stress fluid above the volume fraction ([curly or open phi]c) > 3.75 [times] 10-4.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: K. S. Vasu Source Type: research

Swelling of a hemi-ellipsoidal ionic hydrogel for determination of material properties of deposited thin polymer films: an inverse finite element approach
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50805F, PaperVictorien Prot, Hrafn Mar Sveinsson, Kamila Gawel, Ming Gao, Bjorn Skallerud, Bjorn Torger StokkeMechanical properties of selective deposited polymer films at the surface of an ionic hydrogel are deduced using finite element modeling of the constraining effect on the swelling.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Victorien Prot Source Type: research

Structures and pathways for clathrin self-assembly in the bulk and on membranes
We present a coarse-grained model of clathrin that is simple enough to be computationally tractable yet includes key observed qualitative features: a triskelion structure with excluded volume between legs; assembly of polymorphic cages in the bulk; formation of buds on a membrane.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Richard Matthews Source Type: research

Mechano-responsive calix[4]arene-based molecular gels: agitation induced gelation and hardening
Soft Matter, 2013, Advance ArticleDOI: 10.1039/C3SM50577D, PaperXiuqin Cai, Ying Wu, Liya Wang, Ni Yan, Jing Liu, Xiaohua Fang, Yu FangSonication or agitation promotes the gelation of the isopropanol solution of a specially designed and synthesized cholesteryl derivative of calix[4]arene at room temperature, and enhances the strength of the gel.To cite this article before page numbers are assigned, use the DOI form of citation above.The content of this RSS Feed (c) The Royal Society of Chemistry (Source: RSC - Soft Matter latest articles)
Source: RSC - Soft Matter latest articles - May 16, 2013 Category: Chemistry Authors: Xiuqin Cai Source Type: research