IA-CCF: Individual accountability for permissioned ledgers

Permissioned ledger systems allow a consortium of members that do not trust one another to execute transactions safely on a set of replicas. Such systems typically use Byzantine fault tolerance (BFT) protocols to distribute trust, which only ensures safety when fewer than 1/3 of the replicas misbehave. Providing guarantees beyond this threshold is a challenge: current systems assume that the ledger is corrupt and fail to identify misbehaving replicas or hold the members that operate them accountable—instead all members share the blame. We describe IA-CCF, a new permissioned ledger system that provides individual accountability. It can assign blame to the individual members that operate misbehaving replicas regardless of the number of misbehaving replicas or members. IA-CCF achieves this by signing and logging BFT protocol messages in the ledger, and by using Merkle trees to provide clients with succinct, universally-verifiable receipts as evidence of successful transaction execution. Anyone can audit the ledger against a set of receipts to discover inconsistencies and identify replicas that signed contradictory statements. IACCF also supports changes to consortium membership and replicas by tracking signing keys using a sub-ledger of governance transactions. IA-CCF provides strong disincentives to misbehavior with low overhead: it executes 47,000 tx/s while providing clients with receipts in two network round trips

Properties of an alkali-thermo stable xylanase from Geobacillus thermodenitrificans A333 and applicability in xylooligosaccharides generation

An extracellular thermo-alkali-stable and cellulase-free xylanase from Geobacillus thermodenitrificans A333 was purified to homogeneity by ion exchange and size exclusion chromatography. Its molecular mass was 44 kDa as estimated in native and denaturing conditions by gel filtration and SDS-PAGE analysis, respectively. The xylanase (GtXyn) exhibited maximum activity at 70 °C and pH 7.5. It was stable over broad ranges of temperature and pH retaining 88 % of activity at 60 °C and up to 97 % in the pH range 7.5–10.0 after 24 h. Moreover, the enzyme was active up to 3.0 M sodium chloride concentration, exhibiting at that value 70 % residual activity after 1 h. The presence of other metal ions did not affect the activity with the sole exceptions of K+ that showed a stimulating effect, and Fe2+, Co2+ and Hg2+, which inhibited the enzyme. The xylanase was activated by non-ionic surfactants and was stable in organic solvents remaining fully active over 24 h of incubation in 40 % ethanol at 25 °C. Furthermore, the enzyme was resistant to most of the neutral and alkaline proteases tested. The enzyme was active only on xylan, showing no marked preference towards xylans from different origins. The hydrolysis of beechwood xylan and agriculture-based biomass materials yielded xylooligosaccharides with a polymerization degree ranging from 2 to 6 units and xylobiose and xylotriose as main products. These properties indicate G. thermodenitrificans A333 xylanase as a promising candidate for several biotechnological applications, such as xylooligosaccharides preparation

Interfacial Reaction During High Energy Ball Milling Dispersion of Carbon Nanotubes into Ti6Al4V

The unique thermal and mechanical properties of carbon nanotubes (CNTs) have made them choice reinforcements for metal matrix composites (MMCs). However, there still remains a critical challenge in achieving homogeneous dispersion of CNTs in metallic matrices. Although high energy ball milling (HEBM) has been reported as an effective method of dispersing CNTs into metal matrices, a careful selection of the milling parameters is important not to compromise the structural integrity of CNTs which may cause interfacial reactions with the matrix. In this study, multi-walled carbon nanotubes (MWCNTs) were purified by annealing in argon and vacuum atmospheres at 1000 and 1800 °C, respectively, for 5 h to remove possible metallic catalyst impurities. Subsequently, 1, 2 and 3 wt.% MWCNTs were dispersed by adapted HEBM into Ti6Al4V alloy metal matrix. Raman spectroscopy (RS), x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectrometry and transmission electron microscopy techniques were used to characterize the as-received and annealed MWCNTs, as well as the admixed MWCNT/Ti6Al4V nanocomposite powders. The experimental results showed that vacuum annealing successfully eliminated retained nickel (Ni) catalysts from MWCNTs, while the adapted HEBM method achieved a relative homogeneous dispersion of MWCNTs into the Ti6Al4V matrix and helped to control interfacial reactions between defective MWCNTs and the metal matrix

Comparison of sleep quality and quality of life indexes with sociodemographic characteristics in patients with chronic kidney disease

Aims: Chronic kidney disease (CKD) is a serious health problem due to high mortality and morbidity, negative impact on the patients’ quality of life (QOL), high diagnostic and therapeutic cost, and the burden on society. Sleep, which is one of the main needs of the human body, is important regarding the health and QOL in all ages. The objective of our study was to plan the quality of sleep and life quality in adults with CKD.Materials and Methods: Total 240 cases (91 healthy volunteers, 75 predialysis patients, and 74 hemodialysis (HD) patients) were included in our study. Our study was designed as a prospective survey with a face‑to‑face interview method. The sleep quality was evaluated with Pittsburgh Sleep Quality Index (PSQI). The WHO Quality of Life‑short version (BREF) survey questions were used for QOL, and scoring was performed.Results: The analysis showed that the results of PSQI scores, QOL scores, and evaluation of the age variable were statistically significant (P = 0.001, P < 0.001, P < 0.001, respectively). Likewise, the PSQI scores were low in healthy volunteers but were the highest in predialysis patients. The scores of the HD patients were between the scores of predialysis and healthy volunteers. The score of the QOL increased with educational level. There was a positive correlation between Modification of Diet in Renal Disease (MDRD) level and QOL (P < 0.001; r = 0.260) and a negative correlation between MDRD level and PSQI score (P < 0.001, r = −0.202).Conclusion: Like in HD patients, close follow‑up of predialysis patients with CKD is critical considering the resolution of the encountered problems. We believe that the increase in QOL and sleep in patients with CKD may decrease the morbidity.Keywords: Chronic kidney disease, quality of life, sleep qualit

Performance and exhaust emissions of a biodiesel engine

ARCAKLIOGLU, Erol/0000-0001-8073-5207; ERDIL, AHMET/0000-0002-6659-1195WOS: 000236427000006In this study, the applicabilities of Artificial Neural Networks (ANNs) have been investigated for the performance and exhaust-emission values of a diesel engine fueled with biodiesels from different feedstocks and petroleum diesel fuels. The engine performance and emissions characteristics of two different petroleum diesel-fuels (No. I and No. 2), biodiesels (from soybean oil and yellow grease). and their 20% blends with No. 2 diesel fuel were used as experimental results. The fuels were tested at full load (100%) at 1400-rpm engine speed, where the engine torque was 257.6 Nm. To train the network, the average molecular weight, net heat of combustion, specific gravity, kinematic viscosity, C/H ratio and cetane number of each fuel are used as the input layer, while outputs are the brake specific fuel-consumption, exhaust temperature, and exhaust emissions. The back-propagation learning algorithm with three different variants, single layer, and logistic sigmoid transfer function were used in the network. By using weights in the network, formulations have been given for each output. The network has yielded R-2 values of 0.99 and the mean % errors are smaller than 4.2 for the training data, while the R-2 values are about 0.99 and the mean%, errors are smaller than 5.5 for the test data. The performance and exhaust emissions from a diesel engine, using biodiesel blends with No. 2 diesel fuel Lip to 20%,, have been predicted using the ANN model. (C) 2005 Elsevier Ltd. All rights reserved

Antimicrobial activity of Bacillus strains isolated from spring water and a novel bacteriocin: RS108

The aim of this research was to investigate the bacteriocins produced by Bacillus strains isolated from the spring water of Rize, in Turkey. Bacillus cereus RS108 was identified by both conventional and molecular methods, bacteriocin RS108 which was produced by RS108, was partially characterized. A broad range of indicator strains, including several species of bacteria and yeast like.fungi, was inhibited by a crude bacteriocin obtained from culture supernatant fluid. The best antimicrobial activity of RS108 was detected on S. pyogenes, L. monocytogenes, and another B. cereus strains-and at the late exponential growth phase. RS108 was stable at 90°C, but the activity was lost when the temperature reached 100 °C. It was inactivated by proteinase K. It was resistant 10% ration of some solvent (chloroform, ethanol etc.), but sensitive high concentration. Bacteriocin activity was observed in the pH range of 3.0-9.0. SDS-PAGE analysis of the partially purified bacteriocin shows that the molecular weight of bacteriocin RS108 is approximately 4 kDa

Hypercrosslinked polystyrene sulphonic acid catalysts for the esterification of free fatty acids in biodiesel synthesis

New sulphonic acid catalysts supported on hypercrosslinked polystyrene have been studied in the esterification of oleic acid with methanol and in the rearrangement of α-pinene to camphene and limonenes. The catalysts have been characterised in terms of specific surface areas and porosities, affinities for water and for cylcohexane vapours, and both concentrations and strengths of acid sites. They have been compared with conventional macroporous polystyrene sulphonic acids (Amberlysts 15 and 35) and SAC-13, a composite between Nafion and silica. The results show that the hypercrosslinked polystyrene sulphonic acids, despite exhibiting relatively low concentrations of acid sites and acid site strengths below those of Amberlysts 15 and 35, are very much more catalytically active than conventional resins in reactions such as the esterification in which high acid site strengths are not required. It is thought that this is due to the highly accessible acid sites throughout the catalyst particles. Reusability studies are reported and it appears that the temperature at which the catalyst is used is important in controlling and minimising catalyst deactivation