The role of environmental factors and medium composition on bacteriocin production by an aquaculture probiotic Enterococcus faecium MC13 isolated from fish intestine

The aim of this study was to optimize medium composition for higher yield of total viable cells and bacteriocin by Enterococcus faecium MC13. The factors such as peptone, meat extract, yeast extract, lactose, glycerol, tween 80, triammonium citrate and K₂HPO₄ were selected based on the Lactobacillus MRS medium composition. Two level factorial designs (FD) and steepest ascent path were performed to identify vital factors among the variables. Through the 2^?8 FD, peptone, yeast extract and lactose were found to be significant factors involved in the enhanced production of viable cells and bacteriocin. Therefore, these three foremost factors were further optimized by central composite design to achieve efficient yield. The optimum MRS composition was found to be peptone (40.0 g/L), meat extract (30.0 g/L), yeast extract (40.0 g/L), lactose (24.0 g/L), glycerol (5.8 g/L), Tween 80 (3.0 g/L), triammonium citrate (1.0 g/L), K₂HPO₄ (2.5 g/L), MgSO₄·7H₂O (0.10 g/L), MnSO₄·7H₂O (0.05 g/L) and dipotassium PO₄ (2.0 g/L). The optimized growth medium allowed higher amount of bacteriocin activity (36,100 AUml^?1) and total viable cells (14.22 LogCFUml^?1) production which were two-times higher than the commercial MRS medium.     

Preparation of nano-CaO using thermal-decomposition method

CaO is an important inorganic material, which can be used as catalyst, toxic-waste remediation agent, adsorbent etc. In order to make use of CaO, nano-CaO was prepared by thermal-decomposition method using Ca(NO₃)₂.4H₂O as precursor, NaOH aqueous solution as precipitant, and ethylene glycol as medium in this paper. Characteristics of samples were measured by TGA, XRD, TEM et al techniques. The results showed that the size of nano-CaO about 14 nm could be obtained under the conditions (calcinations temperature 500 °C, calcinations time 1.5 h, heating rate of calcinations 5 °C/min). It is a very simple and effective method to prepare nano-CaO.     

Evaluation of connection flexibility in cold formed steel racks

Steel storage racks are three-dimensional framed structures fabricated from cold formed steel sections, wherein hook-in end connectors are used to make beam-column connections which are basically boltless and semi-rigid in nature. Different types of beam end connectors with different geometry of the connected members are available, making it impossible to develop a generalized analytical model. Only very few theoretical models are available to evaluate the performance of the joints for some typical connectors. More often experimental evaluation and numerical studies are needed to predict the behaviour of every different type of connectors. In the present study eighteen experiments were conducted on a commercially available pallet rack connection by varying the most influencing parameters such as thickness of the column, depth of the connector and the depth of the beam. The main objective of this work is to quantify the beam to column joint, flexibility of commonly used pallet rack frame and to develop a general Frye-Morris type/three parameter power model type moment versus relative rotation relationship. A companion finite element shell model that simulates the experimental behaviour closely is developed using ABAQUS finite element software, which is also used for further parametric studies. Using the three major variables as size parameters, a Frye-Morris type of equation has been proposed. Some calibration studies have also been carried out. Using the ultimate moment capacity, initial connection stiffness and the shape parameter obtained, a three parameter power model has also been proposed to represent the moment-rotation behaviour of the boltless connections.     

Environmental impacts of utilizing waste steel slag aggregates as recycled road construction materials

Slag is an industrial waste generated during the steelmaking process. Electric arc furnace slag (EAFS) and ladle furnace slag (LFS) are both produced at different stages of steelmaking process, respectively, in electric arc furnaces and refining ladle furnaces. As part of this research, an extensive suite of engineering and environmental tests were undertaken on steel slag aggregates to evaluate their potential usage as road construction materials. The engineering assessment included particle size distribution, hydrometer, organic content, flakiness index, Atterberg limits, particle density, water absorption, pH, minimum and maximum dry densities with a vibrating table, modified compaction, California bearing ratio (CBR) and Los Angeles abrasion tests. In addition, a suite of environmental tests comprising total and leachable heavy metal tests were undertaken on both types of steel slag aggregates. From an environmental perspective, EAFS and LFS were found to pose no environmental risks for use as aggregates in roadwork applications. The engineering properties of LFS aggregates with its satisfactory geotechnical and environmental results, particularly its high CBR values, indicated that the material was ideal for usage as a construction material in roadwork applications such as pavement base/subbases and engineering fills. EAFS, with its comparatively lower CBR value, was found to be only suitable to use as a construction material for pavement subbases and engineering fills. The usage of steel slag aggregates in roadwork applications would bring about a practical end-of-life alternative for their sustainable reuse and possibly divert large amount of these waste materials from landfills.     

Design and evaluation of Operation Grade Decay Heat Removal System of PFBR

The decay heat removal (DHR) system removes the decay heat generated (by radioactive decay of fission products) in the core after the reactor is shut down, thereby ensuring proper cooling of the core sub assemblies and limiting main vessel, internals and sodium temperature within safe limits. There are two diverse paths for removal of decay heat from the reactor, namely, Safety Grade Decay Heat Removal System (SGDHRS) and Operation Grade Decay Heat Removal System (OGDHRS). OGDHR circuit is used when at least one secondary sodium loop, DHR related steam water circuit and off site power supply is available and SGDHR circuit is used when OGDHR system is not available or when both the secondary loops are not available for DHR. This paper provides brief details of the design and evaluation of OGDHRS.     

Inductive logic programming for knowledge discovery from MRI data

Describes a tool for quantitatively discriminating between meningioma and astrocytoma tumors. One of the uses of magnetic resonance imaging (MRI) in clinical diagnosis is in-vivo discrimination between tumor and normal tissue and between tumor types in the brain. There is much interest in increasing the qualitative and quantitative information available from these images. This article presents a study that uses the inductive logic programming tool Progol on measurements of signal intensities in clinical scan images of 28 patients (18 with meningiomas and 10 with astrocytomas) to attempt to discover knowledge that quantitatively dissriminates between the two types of tumors     

Enhanced Active Queue Management for Multi-hop Networks

Wireless networks play a very important role in today’s modern world, convincingly surpassing the wired infrastructure in terms of popularity. Hence, it is important to ensure that services which access wired networks should also be accessible using a wireless network without any performance degradation. One of the most common variants in wireless communications is the Wireless Mesh Network (WMNs). WMNs exploit multi-hop wireless communications between wireless access points. Hence, the effective bandwidth decreases as the number of hops increases in a WMN, thus increasing latency and resulting in reduced performance. This may be due to spatial contention, multipath fading, interference or inefficient queuing mechanisms etc. Here we take queuing mechanisms into consideration and study the QMMN algorithm (Queue Management for Multi-hop Networks) which tends to improve throughput, fairness and reduce global synchronization problems. Based on our study, we implement a modified version of the QMMN algorithm, otherwise called the Enhanced QMMN (EQMMN) algorithm. EQMMN can be considered an effective algorithm which solves the problem of fairness between flows (either responsive or unresponsive) and eventually improves TCP throughput at wireless access points. Our experimental results prove that EQMMN algorithms have better performance characteristics such as throughput (TCP) and fairness index compared to QMMN algorithms.     

A Novel Synthesis,Structural, Morphological,and Opto-magnetic Characterizations of Magnetically Separable Spinel Co x Mn1−x Fe2O4 (0 ≤ x ≤ 1) Nano-catalysts

Spinel Co _x Mn_1?x Fe₂O₄ (0≤x≤1) nano- crystals were successfully synthesized by a simple microwave-assisted combustion method. High-resolution scanning electron microscopy (HR-SEM) and transmission electron microscopy (HR-TEM) analysis was used to study the morphological variations and found the particle-like nanocrystal morphologies. Energy dispersive X-ray (EDX) results showed that the composition of the elements were relevant as expected from the combustion synthesis. Powder X-ray diffraction (XRD) analysis showed that all composition was found to have cubic spinel-type structure. Average crystallite size of the samples was found to be in the range of 10.36–21.16 nm. The lattice parameter decreased from 8.478 to 8.432 Å with increasing Co²⁺ content. Fourier transform infrared (FT-IR) spectra showed two strong absorption peaks observed at lower frequency (～435 to ～800 cm^?1), which can be assigned to the M–O (Mn, Co, and Fe) bonds. UV-Visible diffuse reflectance spectroscopy (DRS) shows that the energy band gap of pure MnFe₂O₄ is 1.78 eV and with increase in the Co²⁺ ion, it increases from 1.87 to 2.33 eV. Addition of Co²⁺ in MnFe₂O₄ reduces the particle size, which can be confirmed by the blue shift in the photoluminescence (PL) spectra. Vibrating sample magnetometer (VSM) results that confirmed a weak ferromagnetic behavior for all composition with saturation magnetization values in the range of 50.05 ±04 to 67.09 °03 emu/g. All composition of spinel Co _x Mn_1?x Fe₂O₄ nano-crystals were successfully tested as catalyst for the oxidation of benzyl alcohol to benzaldehyde, which has resulted 87.32 and 94.28 % conversion efficiency of MnFe₂O₄ and Co_0.6Mn_0.4Fe₂O₄, respectively.     

Strong quantum confinement effect in nanocrystalline cerium oxide

Highly uniform and well-dispersed cerium oxide quantum dots were successfully synthesized by simple precipitation method by using cerium ammonium nitrate and ammonium hydroxide as precursor materials with suitable conditions. The X-ray diffraction pattern indicates the formation of cubic phase CeO₂. The average particle size of cerium oxide from high resolution transmission electron microscopy (HRTEM) was found to be 3 nm. The X-ray photoelectron (XPS) spectrum confirms the presence of Ce³⁺ in CeO₂. Optical studies by UV–vis spectroscopy for the synthesized CeO₂ nanoparticles exhibit a blue shift (E_g = 3.78 eV) with respect to the bulk material (E_g = 3.15 eV) due to quantum confined exciton absorption.     

As(V) removal using carbonized yeast cells containing silver nanoparticles

The present study involves the development of adsorbent containing silver nanoparticles for arsenate removal using silver reducing property of a novel yeast strain Saccharomyces cerevisiae BU-MBT-CY1 isolated from coconut cell sap. Biological reduction of silver by the isolate was deduced at various time intervals. The yeast cells after biological silver reduction were harvested and subjected to carbonization at 400 °C for 1 h and its properties were analyzed using Fourier Transform Infra-Red spectroscopy, X-ray diffraction, scanning electron microscope attached with energy dispersive spectroscopy and transmission electron microscope. The average size of the silver nanoparticles present on the surface of the carbonized silver containing yeast cells (CSY) was 19 ± 9 nm. The carbonized control yeast cells (CCY) did not contain any particles on its surface. As(V) adsorption efficiency of CCY and CSY was deduced in batch mode by varying parameters like contact time, initial concentration, and pH. Desorption studies were also carried out by varying the pH. The experimental data were fitted onto Langmuir and D-R Isotherms and Lagergren and pseudo second order kinetic models. The CSY was more efficient in arsenate removal when compared to CCY.