Current production by bacterial communities in microbial fuel cells enriched from wastewater sludge with different electron donors

Electricity production by bacterial communities enriched from wastewater sludge with lactate, succinate, N-acetyl-D-glucosamine (NAG), acetate, formate, and uridine were monitored in dual-chamber microbial fuel cells (MFCs). Stable electricity production was observed after 300 h for communities enriched from lactate, acetate, and formate, while communities enriched with succinate, NAG, and uridine stabilized only after 700 h. The average peak current densities and maximum power densities generated from bacterial consortia were significantly higher than those generated from pure cultures of Shewanella oneidensis MR-1. Microbial assemblages were analyzed by DGGE, and planktonic and anode-attached bacterial communities varied as a function of electron donors: Firmicutes, β-Proteobacteria, and Bacteroidetes dominated the planktonic bacterial communities while anode-attached communities consisted mainly of δ-Proteobacteria, β-Proteobacteria, and Firmicutes. Similar bacterial populations were enriched in MFCs fed with lactate, NAG, and uridine and with succinate, acetate, and formate. Cross-feeding experiments with different fuels indicated that enriched microbial consortia were able to utilize a variety of fuel sources and displayed considerable stability, efficiency, and robustness of power generation in comparison to pure cultures. In addition, characterizations of cultivated Shewanella strains suggested that DGGE analysis likely missed active members of exoelectrogenic populations.     

Preparation and nanoencapsulation of l-asparaginase II in chitosan-tripolyphosphate nanoparticles and in vitro release study

This paper describes the production, purification, and immobilization of l-asparaginase II (ASNase II) in chitosan nanoparticles (CSNPs). ASNase II is an effective antineoplastic agent, used in the acute lymphoblastic leukemia chemotherapy. Cloned ASNase II gene (ansB) in pAED4 plasmid was transformed into Escherichia coli BL21pLysS (DE3) competent cells and expressed under optimal conditions. The lyophilized enzyme was loaded into CSNPs by ionotropic gelation method. In order to get optimal entrapment efficiency, CSNP preparation, chitosan/tripolyphosphate (CS/TPP) ratio, and protein loading were investigated. ASNase II loading into CSNPs was confirmed by Fourier transform infrared (FTIR) spectroscopy, and morphological observation was carried out by transmission electron microscopy. Three absolute CS/TPP ratios were studied. Entrapment efficiency and loading capacity increased with increasing CS and TPP concentration. The best ratio was applied for obtaining optimal ASNase II-loaded CSNPs with the highest entrapment efficiency. Size, zeta potential, entrapment efficiency, and loading capacity of the optimal ASNase II-CSNPs were 340 ± 12 nm, 21.2 ± 3 mV, 76.2% and 47.6%, respectively. The immobilized enzyme showed an increased in vitro half-life in comparison with the free enzyme. The pH and thermostability of the immobilized enzyme was comparable with the free enzyme. This study leads to a better understanding of how to prepare CSNPs, how to achieve high encapsulation efficiency for a high molecular weight protein, and how to prolong the release of protein from CSNPs. A conceptual understanding of biological responses to ASNase II-loaded CSNPs is needed for the development of novel methods of drug delivery.     

OIL SOURCE ROCK POTENTIAL OF THE LACUSTRINE JURASSIC SIM UUJU FORMATION, WEST KOREA BAY BASIN: Part I: Oil source rock correlation and environment of deposition

The offshore West Korea Bay (WKB) Basin is one of several NE-SW rift basins which formed over thin continental crust in Korea and eastern China during the Late Mesozoic and Early Cenozoic, and is characterised by a two-layered structure, with a Cenozoic basin superposed on a pre-Tertiary basin. Paraffinic oils recovered from Mesozoic and Tertiary sandstone intervals are thought to have been generated from different source beak. The Sim Uuju Formation consists mainly of fluvially-derived shales and sandstones deposited in a large, open, fresh-water, deep, tectonic lake. which occupied wide sub-basins formed by normal faults under a semi-humid climate, as a result of initial rifting during the Upper Jurassic. A probable source bed (400– to 500–m thick) has been geochemically located in the basinal offshore area of the Sim Uuju sequence penetrated by Well 606. The Jurassic bed could be considered as a potential source for the Mesozoic oil, provided that it contains the right type and amount of organic matter which has reached the stage of oil generation .     

Aneurysms related to cerebral arteriovenous malformations: superselective angiographic assessment in 58 patients

PURPOSE: To report the comprehensive superselective angiographic characteristics of aneurysms associated with cerebral arteriovenous malformations. METHOD: One hundred consecutive patients referred for cerebral arteriovenous malformation embolization underwent preembolization superselective angiography. Superselective angiograms were obtained after microcatheterization of arteriovenous malformation pedicles, and assessed for number and location of aneurysms related to the malformation. A chi 2 test was conducted to correlate these parameters with the onset of intracranial hemorrhage. RESULTS: Aneurysms were demonstrated in 58 of 100 patients. Single aneurysms were found in 24 patients and multiple aneurysms in 34. Presence and number of aneurysms were found to correlate significantly with a clinical presentation of hemorrhage. CONCLUSION: Superselective angiography was found to be of paramount importance in elucidating the precise and detailed angioarchitecture of brain arteriovenous malformations.     

Managing on-chip inductive effects

With process technology and functional integration advancing steadily, chips are continuing to grow in area while critical dimensions are shrinking. This has led to the emergence of on-chip inductance to be a factor whose effect on performance and on signal integrity has to be managed by chip designers and has to be sometimes traded off against other performance parameters. In this paper, we cover several techniques to reduce on-chip inductance which in turn improve timing predictability and reduce signal delay and crosstalk noise. We present experimental results obtained from simulations of a typical high performance bus structure and a clock tree structure to examine the effectiveness of some of the different inductance reduction techniques.     

II. Yeast sequencing reports. A putative P-type Cu2+-transporting ATPase gene on chromosome II of Saccharomyces cerevisiae

We have sequenced a gene on the right arm near the telomere of chromosome II of Saccharomyces cerevisiae which codes for a putative P-type cation-transporting ATPase (PCA1). The gene codes for a 1216 amino acids protein. The PCA1 gene expresses a 3·5 kb message in both haploid and diploid cells when grown in glucose-based rich medium YPD. The gene product is most similar at the C-terminal region to a human copper-transporting ATPase and Enterococcus hirae copper-transporting ATPases and also an N-terminal dithiol region that was proposed to be a ‘metal-binding motif’. Cells lacking PCA1 display no obvious phenotype when tested under standard conditions; whereas they cease growth much earlier than the isogenic wild-type cells in a minimal medium with high copper concentration. Overexpression of PCA1 under GAL1/10 promoter in yeast cells causes poor growth. We also show that yeast strains carrying PCA1 in multiple copies grow slower than isogenic wild-type strains in a minimal synthetic medium containing 0·3 mM-CuSO₄. The sequence has been deposited in the EMBL data library under Accession Number Z29332.     

Coded and Scalar Prefix Trees: Prefix Matching Using the Novel Idea of Double Relation Chains

In this paper, a model is introduced named double relation chains (DRC) based on ordered sets. It is proved that using DRC and special relationships among the members of an alphabet, vectors of this alphabet can be stored and searched in a tree. This idea is general; however, one special application of DRC is the longest prefix matching (LPM) problem in an IP network. Applying the idea of DRC to the LPM problem makes the prefixes comparable like numbers using a pair of w‐bit vectors to store at least one and at most w prefixes, where w is the IP address length. This leads to good compression performance. Based on this, two recently introduced structures called coded prefix trees and scalar prefix trees are shown to be specific applications of DRC. They are implementable on balanced trees which cause the node access complexity for prefix search and update procedures to be O(log n) where n is the number of prefixes. As another advantage, the number of node accesses for these procedures does not depend on w. Additionally, they need fewer number of node accesses compared to recent range‐based solutions. These structures are applicable on both IPv4 and IPv6, and can be implemented in software or hardware.     

A wide range,high yield and good performance pHEMT switch for MMIC phase shifter

A low-cost method with high yield and good performance is presented by pHEMTs (pseudomorphic high electron mobility transistors) to be used in phase shifter switches. In this method, the capacitor in “off” mode (C_off) of transistor is reduced, without variation of the transistor structure. The transistor structure in switch mode can be optimised. This method increases the transistor isolation in turn “off” mode, while there is no change in resistance of the transistor in “on” mode (R_on). Transistor dimension is determined in turn “off” mode (V_g = ?4.5 V) and standard form of 4 × 75 μm. So, in this method, insertion loss will be reduced without a perceptible change in transistor dimension. Thus, design and fabrication capability of some circuits such as phase shifters, antenna switches, SPDT (single port double throw) – without any change in technology – are increasing. In this paper, post layout and measurement result for a sample block of phase shifter are shown.     

Springback Analysis of Two-Layer Strips in Clad Cold Bimetal Bending

Recently, multi-layer metallic materials are increasingly being employed in a wide variety of industrial applications in order to create materials with combined functions and higher performances. Based on a nonlinear finite element analysis, the present study aims to develop a model for investigating the effects of sheet thickness and position on the springback of a stainless-steel clad aluminum sheet. It addresses three different types of strain hardening models, namely isotropic, cyclic, and Johnson–Cook (JC). A purely empirical approach, JC considers strain, strain rate, and temperature in elastic–plastic deformation. Good agreements are seen between the obtained results and the experimental verification data, therefore it is concluded that the bending behavior of a bi-layer metallic sheet/strip can be accurately predicted by the proposed model.     

High-power,high-voltage IGBT applications: series connection of IGBTs or multilevel converters?

In this paper a detailed quantitative comparison between two competing high-voltage converter technologies is performed, namely series connection of semiconductor power devices versus multilevel converters. The comparison is based on converter losses (conduction and switching), total harmonic distortion, and distortion factor for the output phase and line voltages at different modulation frequency ratios. A new method is presented for calculating the conduction loss of cascaded-type multilevel converters which use carrier-based pulse width modulation.