Factorization of Joint Probability Mass Functions into Parity Check Interactions

We show that any joint probability mass function (PMF) can be expressed as a product of parity check factors and factors of degree one with the help of some auxiliary variables, if the alphabet size is appropriate for defining a parity check equation. In other words, marginalization of a joint PMF is equivalent to a soft decoding task as long as a finite field can be constructed over the alphabet of the PMF. In factor graph terminology this claim means that a factor graph representing such a joint PMF always has an equivalent Tanner graph. We provide a systematic method based on the Hilbert space of PMFs and orthogonal projections for obtaining this factorization.Comment: 5 pages, 1 figures, appeared in the proceedings of ISIT 2009; Changed content, more recent version than as appeared in the proceeding

Biosorption of phenol and 2-chlorophenol by Funalia trogii pellets

Cataloged from PDF version of article.The removal of phenol (Ph) and 2-chlorophenol (2-CPh) from aqueous solution by native and heat inactivated fungus Funalia trogii pellets were investigated. The effects of contact time, solid/liquid ratio, optimum pH and temperature on the phenols removal capacity by the pellets were established. The removal efficiency of phenols increased significantly with increasing biomass dose. The optimum pH was detected to be 8.0. The second-order equations are described and evaluated on the basis of a comparative estimation of the corresponding coefficients. The phenol removal equilibrium isotherm was modeled by the Langmuir equations. The enthalpy change values were obtained between -7.62 and -10.64 kJ/mol. This indicated that the uptake of phenols either on native or heat inactivated fungal pellets was based on a physical adsorption process. © 2008 Elsevier Ltd. All rights reserved

Poly (hydroxyethyl methacrylate-glycidyl methacrylate) films modified with different functional groups: In vitro interactions with platelets and rat stem cells

Cataloged from PDF version of article.Copolymerization of 2-hydroxyethylmethactylate (HEMA) with glycidylmethacrylate (GMA) in the presence of alpha-alpha'-azoisobisbutyronitrile (AIBN) resulted in the formation of hydrogel films carrying reactive epoxy groups. Thirteen kinds of different molecules with pendant -NH2 group were used for modifications of the p(HEMA-GMA) films. The -NH2 group served as anchor binding site for immobilization of functional groups on the hydrogel film via direct epoxy ring opening reaction. The modified hydrogel films were characterized by FTIR, and contact angle studies. In addition, mechanical properties of the hydrogel films were studied, and modified hydrogel films showed improved mechanical properties compared with the non-modified film, but they are less elastic than the non-modified film. The biological activities of these films such as platelet adhesion, red blood cells hemolysis, and swelling behavior were studied. The effect of modified hydrogel films, including -NH2, (using different aliphatic -CH2 chain lengths) -CH3, -SO3H, aromatic groups with substituted -OH and -COOH groups, and amino acids were also investigated on the adhesion, morphology and survival of rat mesenchymal stem cells (MSCs). The MTT colorimetric assay reveals that the p(HEMA-GMA)-GA-AB, p(HEMA-GMA)-GA-Phe, p(HEMA-GMA)-GA-Trp, p(HEMA-GMA)-GA-Glu formulations have an excellent biocompatibility to promote the cell adhesion and growth. We anticipate that the fabricated p(HEMA-GMA) based hydrogel films with controllable surface chemistry and good stable swelling ratio may find extensive applications in future development of tissue engineering scaffold materials, and in various biotechnological areas. (c) 2012 Elsevier B.V. All rights reserved

Coeliac trunk and common hepatic artery variations in children: an analysis with computed tomography angiography

Background: Understanding the coeliac trunk (CeT) and hepatic artery anatomy is important not only in preventing iatrogenic injuries but also in planning surgical procedures in children. Therefore, the aim of this study is to analyse the prevalence of CeT and common hepatic artery (CHA) variations in the paediatric population.   Materials and methods: One hundred and seventy-four children who underwent abdominal multidetector computed tomography (MDCT) angiography, either because of trauma or liver transplantation, were analysed retrospectively. The patterns of CeT, CHA and their variant branches were revealed and compared with previous studies involving adults.   Results: A total of 157 (90.2%) of the 174 patients had normal CeT anatomy, whereas 17 (9.8%) had variations. Five types of CeT variations were identified according to Song’s classification in which ‘hepatosplenic trunk + left gastric artery + superior mesenteric artery’ was the most prevalent. One hundred-twelve (64.4%) of the 174 patients had normal CHA anatomy; however, 62 (35.6%) had variations. Six types of CHA variations were identified according to Michel’s and Hiatt’s classification. The most common was ‘replaced left hepatic artery originating from left gastric artery’.   Conclusions: The prevalences of CeT and hepatic artery variations are high in children, as they are in older patients. Awareness of these variations is important in terms of avoiding iatrogenic injury and in promoting surgical procedure planning for liver transplantation or abdominal tumour surgery

Immobilization of laccase on itaconic acid grafted and Cu(II) ion chelated chitosan membrane for bioremediation of hazardous materials

Background: Chitosan membranes were formed through a phase inversion technique and then cross-linked with epichlorohydrin (CHX). Heterogeneous graft copolymerization of itaconic acid (IA) onto membrane was carried out with different monomer concentrations (CHX-g-p(IA)). The membrane properties such as equilibrium swelling ratio, porosity, and contact angle were measured, together with analysis by scanning electron microscopy (SEM), energy dispersive analysis of X-rays (EDAX), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy. Results: The Cu(II) ion incorporated membranes (i.e. CHX-g-p(IA)-Cu(II)) were used for reversible immobilization of laccase using CHX-g-p(IA) membrane as a control system. Maximum laccase adsorption capacities of the CHX-g-p(IA) and CHX-g-p(IA)-Cu(II) membranes (with 9.7% grafting yield) were found to be 6.3 and 17.6 mg mL -1 membrane at pH 4.0 and 6.0, respectively. The K m value for immobilized laccase on CHX-g-p(IA)-Cu(II) (4.16 × 10 -2 mmol L -1) was 2.11-fold higher than that of free enzyme (1.97 × 10 -2 mmol L -1). Finally, the immobilized laccase was used in a batch system for degradation of three different dyes (Reactive Black 5, RB5; Cibacron Blue F3GA, CB; and Methyl Orange, MO). The immobilized laccase on CHX-g-p(IA)-Cu(II) membrane was more effective for removal of MO dye than removal of CB and RB5 dyes. CONCLUSION: Flexibility of the enzyme immobilized grafted polymer chains is expected to provide easy reaction conditions without diffusion limitation for substrate dye molecules and their products. The support described, prepared from green chemicals, can be used for the immobilization of industrially important enzymes. © 2012 Society of Chemical Industry

Matematičko modeliranje u svrhu predviđanja i optimiranja zavarivačke kupke kod TIG zavarivanja

In this work, nonlinear and multi-objective mathematical models were developed to determine the process parameters corresponding to optimum weld pool geometry. The objectives of the developed mathematical models are to maximize tensile load (TL), penetration (P), area of penetration (AP) and/or minimize heat affected zone (HAZ), upper width (UW) and upper height (UH) depending upon the requirements.Razvijeni su nelinearni i multi-objektni matematički modeli da bi odredili parametre s optimalnom geometrijom zavarivačke kupke. Cilj razvijanja matematičkih modela je postići maksimalna vlačna čvrstoća, penetracija, područje pretaljivanja i/ili minimalna zona utjecaja topline, širina i nadvišenje zavara ovisno o postavljenim zahtjevima

Biosorption of Cr(VI) by free and immobilized Pediastrum boryanum biomass: equilibrium, kinetic, and thermodynamic studies

15th International Symposium on Toxicity Assessment (ISTA) -- JUL 03-08, 2011 -- City Univ Hong Kong, Hong Kong, PEOPLES R CHINAWOS: 000306790200053PubMed ID: 22374187The biosorption of Cr(VI) from aqueous solution has been studied using free and immobilized Pediastrum boryanum cells in a batch system. The algal cells were immobilized in alginate and alginate-gelatin beads via entrapment, and their algal cell free counterparts were used as control systems during biosorption studies of Cr(VI). The changes in the functional groups of the biosorbents formulations were confirmed by Fourier transform infrared spectra. The effect of pH, equilibrium time, initial concentration of metal ions, and temperature on the biosorption of Cr(VI) ion was investigated. The maximum Cr(VI) biosorption capacities were found to be 17.3, 6.73, 14.0, 23.8, and 29.6 mg/g for the free algal cells, and alginate, alginate-gelatin, alginate-cells, and alginate-gelatin-cells at pH 2.0, which are corresponding to an initial Cr(VI) concentration of 400 mg/L. The biosorption of Cr(VI) on all the tested biosorbents (P. boryanum cells, alginate, alginate-gelatin, and alginate-cells, alginate-gelatin-cells) followed Langmuir adsorption isotherm model. The thermodynamic studies indicated that the biosorption process was spontaneous and endothermic in nature under studied conditions. For all the tested biosorbents, biosorption kinetic was best described by the pseudo-second-order model.PROCORE-France/Hong Kong Joint Res Scheme, Croucher Fdn, KC Wong Educ Fd

In situ functionalization of a cellulosic-based activated carbon with magnetic iron oxides for the removal of carbamazepine from wastewater

The main goal of this work was to produce an easily recoverable waste-based magnetic activated carbon (MAC) for an efficient removal of the antiepileptic pharmaceutical carbamazepine (CBZ) from wastewater. For this purpose, the synthesis procedure was optimized and a material (MAC4) providing immediate recuperation from solution, remarkable adsorptive performance and relevant properties (specific surface area of 551 m2 g-1 and saturation magnetization of 39.84 emu g-1) was selected for further CBZ kinetic and equilibrium adsorption studies. MAC4 presented fast CBZ adsorption rates and short equilibrium times (< 30-45 min) in both ultrapure water and wastewater. Equilibrium studies showed that MAC4 attained maximum adsorption capacities (qm) of 68 ± 4 mg g-1 in ultrapure water and 60 ± 3 mg g-1 in wastewater, suggesting no significant interference of the aqueous matrix in the adsorption process. Overall, this work provides evidence of potential application of a waste-based MAC in the tertiary treatment of wastewaters.publishe