Improved results on an extended dissipative analysis of neural networks with additive time-varying delays using auxiliary function-based integral inequalities

The issue of extended dissipative analysis for neural networks (NNs) with additive time-varying delays (ATVDs) is examined in this research. Some less conservative sufficient conditions are obtained to ensure the NNs are asymptotically stable and extended dissipative by building the agumented Lyapunov-Krasovskii functional, which is achieved by utilizing some mathematical techniques with improved integral inequalities like auxiliary function-based integral inequalities (gives a tighter upper bound). The present study aims to solve the $H_{\infty}, L_2-L_{\infty}$, passivity and $(Q, S, R)$-$\gamma$-dissipativity performance in a unified framework based on the extended dissipativity concept. Following this, the condition for the solvability of the designed NNs with ATVDs is presented in the form of linear matrix inequalities. Finally, the practicality and effectiveness of this approach were demonstrated through four numerical examples

Effect of COD: SO42- Ratio, HRT and Linoleic Acid Concentration on Mesophilic Sulfate Reduction: Reactor Performance and Microbial Population Dynamics

Biological sulfate (SO42-) reduction was examined in anaerobic sequential batch reactors (ASBRs) operated under different hydraulic retention times (HRTs) ranging from 12 to 36 h and COD (Chemical Oxygen Demand)/SO42- ratios of 2.4, 1.6 and 0.8. Competition between SO42- reducing bacteria (SRBs), methane producing archaea (MPAs) and homoacetogens (HACs) was examined in controls and cultures treated with linoleic acid (LA). The ASBR performance was influenced by the COD/SO42- ratio in control cultures with a SO42- reduction of 87% at a COD/SO42- ratio of 0.8. At a 12 h HRT, in both control and LA treated cultures, greater than 75% SO42- removal was observed under all the conditions examined. In control reactors operating at a 36 h HRT, high levels of MPAs belonging to Methanobacteriales and Methanosarcinales were detected; however, in comparison, under low COD/SO42- ratio and with decreasing HRT conditions, a relative increase in SRBs belonging to Desulfovibrio and Desulfatibacillum was observed. Adding 0.5 gL(-1) LA suppressed Methanobacteriales, while increasing the LA concentration to 1 gL(-1) completely suppressed MPAs with a relative increase in SRBs. HACs belonging to Bacteroidetes were observed in the control and in cultures operated at 12 h HRT with a COD/SO42- ratio of 1.6 and fed 0.5 gL(-1) LA; however, with all other LA levels (0.5 and 1.0 gL(-1)) and HRTs (12, 24 and 36 h), HACs were not detected

Statistical optimization of conditions for minimum H-2 consumption in mixed anaerobic cultures: Effect on homoacetogenesis and methanogenesis

Hydrogen (H-2) production using mixed anaerobic cultures often suffers severe yield reduction due to the syntrophic association between H-2 consumers (methanogens and homoacetogens) and H-2 producers (acidogens). The objective of this study was to uncouple the syntrophic association between H-2 producers and consumers by optimizing conditions for minimum H-2 consumption using a Box-Behnken design approach. The factors investigated in this study include temperature, pH and linoleic acid (LA) concentration. A quadratic response surface model was developed to predict the H-2 consumed by mixed anaerobic cultures and the optimum conditions for minimum H-2 consumption were 38 degrees C, pH 5.5 and 2 g L-1 LA. Methanogenesis was inhibited in cultures fed 2 g L-1 LA and maintained at pH 6.0 and 53 degrees C. In comparison, both methanogenesis and homoacetogenesis were inhibited in cultures fed 1-2 g L-1 LA and maintained at a pH of 4.5 (Fig. 2B and 2E and Table 2 Expt. # 1, 2 and 11). Microbial diversity analysis revealed that LA fed cultures was dominated by spore forming Clostridium sp. in addition to Syntrophus aciditrophus. In comparison, control cultures were dominated by Eubacterium sp., Methanocalculus halotolerans and Methanococcoides alaskense. This study described an approach for regulating H-2 consumption in mixed cultures by optimizing process and environmental factors. Understanding the effects of these individual factors and their interaction is important in the full-scale operation of H-2 production facilities. Copyright (C) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Effect of inhibitors on hydrogen consumption and microbial population dynamics in mixed anaerobic cultures

The impact of different chemical microbial stressors (2-bromoethanesulfonate (BES), furfural, fish oil, lauric acid (LUA) and linoleic acid (LA)) on the inhibition of mesophilic hydrogen (H-2) consumption was examined in this study. Hydrogen consumption half-life values were used to compare the extent of inhibition by the different microbial stressing agents. A statistical analysis of the percent H-2 consumed using Tukey\u27s analysis revealed the following trend: Control \u3e fish oil = linoleic acid (LA (C18:2)) = furfural \u3e BES \u3e lauric acid (LUA (C12:0). The terminal restriction fragment length polymorphism (T-RLFP) results indicated that aceticlastic methanogens (Methanosaeta sp., Methanosarcina sp.) and hydrogenotrophic methanogens (Methanococcus sp.) were inhibited by the different chemical stressing agents. Cultures fed LUA and LA had a high abundance of Clostridium sp., Clostridium propionicum and Propionibacterium acnes. In comparison, BES and furfural fed cultures contained large fractions of Clostridium sp., Eubacteria sp. and Bacteroides sp. while in the fish oil fed cultures, the dominant organism detected was Eubacteria sp. This study indicated that H-2 consumption was affected by the chemical stressing agent concentration. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Isolation, purification and biochemical characterization of conotoxin from <i style="">Conus figulinus </i>Linnaeus (1758)

266-271 Cone snails are remarkable for the extent and diversity of gene-encoded peptide neurotoxins that are expressed in their venom apparatus. The protein content of the crude toxin extract of Conus figulinus Linneaus was found to be 1900 μg/mL. The crude extract (dilution up to 10-5) expressed hemolytic activity. The crude extract subjected to gel filtration chromatography yielded 60 fractions; the fractions 7, 12 and 55 showed significant peaks at 280 nm. The fractionated toxin was then characterized by performing SDS-PAGE having the lower peptides ranging from 10 to 43 kDa; two lower peptides below 14 kDa have been identified. The total RNA and purified mRNA were characterized by Agarose gel electrophoresis and for total RNA two prominent bands of 18s and 28s were obtained of which 28s showed double intensity than the other. For mRNA a single band of 6000 base pairs was obtained. </smarttagtype

Studies on isolation and partial purification of lysozyme from egg white of the lovebird (Agapornis species)

Lysozyme was extracted from the egg white of the eggs of lovebird (Agapornis sp.) and partially purified using the dialysis membrane. The amount of lysozyme extracted was determined through absorbanceassays using Micrococcus lysodeikticus cell walls as substrate. The total protein content in the crude (0.5 mg/ml) and partially purified (0.01 mg/ml) enzyme extract was estimated. The presence of lysozyme enzyme in the egg white was confirmed and its molecular weight (14.3 kDa) was  determined through SDS-PAGE

Isolation, characterization and molecular weight determination of collagen from marine sponge Spirastrella inconstans (Dendy)

Collagen is a major structural protein of connective tissues. It can be used as a prosthetic biomaterial applicable to artificial skin, tendon ligaments and development collagen implants. In the present study, an attempt was made to isolate and characterize collagen from the marine sponge, Spirastrella inconstans. The total protein content of sponge collagen was relatively high (32%). While determining the molecular weight of crude and purified collagen through sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), the crude showed three bands (80, 60 and 59 kDa molecular weight) and purified showed only a single band (58 kDa). The structural properties were analyzed by using fourier transform infra red (FT-IR) spectrum and the stability of collagen was also given the single transition peak in differential scanning calorimetry (DSC). The microstructure of sponge collagen showed highly porous and interconnected scaffolds in scanning electron microscopic (SEM) analysis.Keywords: Collagen, Spirastrella inconstans, SDS-PAGE, Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM)African Journal of Biotechnology Vol. 12(5), pp. 504-51

Using a food and paper-cardboard waste blend as a novel feedstock for hydrogen production: Influence of key process parameters on microbial diversity

In this study, fermentation of a thermally treated simulated organic solid waste into hydrogen (H-2) was examined using a pretreated anaerobic mixed culture. The culture was fed a steam exploded food waste plus paper-cardboard waste blend liquor with and without linoleic acid (LA). The individual and interaction effects of the initial pH, LA concentration and the initial chemical oxygen demand (COD) concentration on H-2 and methane (CH4) production was assessed using a Box-Behnken design (BBD). The BBD model predicted a maximum H-2 yield of 87 mL g(-1) COD or 98 mL H-2 g(-1) VS with 1.6 g L-1 LA, an initial pH of 5.93 and an initial COD of 9.34 g COD L-1. The major microbial populations detected in cultures at pH 5.5 with and without LA included Clostridium sp., Enterococcus asini, Enterococcus faecalis, and Lactobacillus gallinarum. The dendrogram for the 16S rRNA gene T-RFs profiles showed four major groups with a similarity index of 72-75% for Clade III. The major H-2-producing populations were grouped in Cade I with a similarity index range of 55-75%. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved

Pretreating mixed anaerobic communities from different sources : correlating the hydrogen yield with hydrogenase activity and microbial diversity

In this study, granular and \ufb02occulated anaerobic mixed cultures were pretreated using heat, shock loading, acid, alkali, linoleic acid (LA) and 2-bromoethane sulphonic acid (BESA). Under mesophilic conditions (37\ub0C) and an initial pH value of 6.0, higher H\u2082 yields were observed for the \ufb02occulated cultures when compared to the granular cultures. The maximum yield for granular cultures treated acid, BESA or LA were statistically the same. Butyric acid fermentation was dominant in a majority of the treated cultures. The maximum hydrogenase evolution speci\ufb01c activity (ESA) (124 \ub1 8 Ue mg VSS\u207b\ub9) at 37\ub0C correlated with the maximum H\u2082 yield for the LA treated \ufb02occulated cultures (1.69 \ub1 0.18 mol mol\u207b\ub9 glucose). The microbial diversity data clearly showed that the low H\u2082 yield in the granular cultures was due to the lower proportion of H\u2082 producers. A principle component analysis (PCA) revealed that the LA treated \ufb02occulated and granular cultures were grouped together and showed more diversity in comparison to other pretreatment methods.Peer reviewed: YesNRC publication: Ye