Soluble‐eggshell‐membrane‐protein‐modified porous silk fibroin scaffolds with enhanced cell adhesion and proliferation properties

In this study, a porous silk fibroin (SF) scaffold was modified with soluble eggshell membrane protein (SEP) with the aim of improving the cell affinity properties of the scaffold for tissue regeneration. The pore size and porosity of the prepared scaffold were in the ranges 200–300 μm and 85–90%, respectively. The existence of SEP on the scaffold surface and the structural and thermal stability were confirmed by energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The cell culture study indicated a significant improvement in the cell adhesion and proliferation of mesenchymal stem cells (MSCs) on the SF scaffold modified with SEP. The cytocompatibility of the SEP‐conjugated SF scaffold was confirmed by a 3‐(4,5‐dimethyltriazol‐2‐y1)‐2,5‐diphenyl tetrazolium assay. Thus, this study demonstrated that the biomimic properties of the scaffold could be enhanced by surface modification with SEP. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40138.     

Evaluation of Robustness of the Biosurfactant Derived from Balanites aegyptiaca (L.) Del.

Balanites aegyptiaca (L.) Del. is a widely distributed xerophytic multipurpose tree. The mesocarp of the fruit of B. aegyptiaca has detergent properties due to the presence of saponins. The stability potential of this biosurfactant at varying pH, temperature, and salinity has not been explored so far. In the present study, the relative surface tensions of five different concentrations of the biosurfactant were studied at different temperatures, salinity, and under pH conditions. This study reveals that this biosurfactant retains its activity over a wide range of pH (3–11) and at high salinity (7% NaCl). It is a thermostable cationic surfactant; surfactant activity was recorded even at 100 °C with the lowest relative surface tension of 0.47. High oil displacement (18.00 mm) was observed when studied with petrol. This biosurfactant was found to have a high emulsification index (E₂₄) of 70% with mustard oil. These results indicate that biosurfactant derived from B. aegyptiaca may find use in a wide range of sectors such as textile, food, cosmetics, oil recovery, and healthcare under a wide range of physical and chemical conditions. It offers an efficient, economically viable, and plant-derived alternative to synthetic detergents and adds a way to maintain a sustainable environment.     

The study of lithium ion de-insertion/insertion in LiMn2O4 and determination of kinetic parameters in aqueous Li2SO4 solution using electrochemical impedance spectroscopy

In this work, we report a basic study on the mechanism of lithium ion de-insertion/insertion process from/into LiMn₂O₄ cathode material in aqueous Li₂SO₄ solution using electrochemical impedance spectroscopy (EIS). An equivalent circuit distinguishing the kinetic parameters of lithium ion de-insertion/insertion is used to simulate the experimental impedance data. The fitting results are in good agreement with the experimental results and the parameters of the kinetic process of Li⁺ de-insertion and insertion in LiMn₂O₄ at different potentials during charge and discharge are obtained using the same circuit. The results indicate that the de-insertion/insertion behavior of lithium ions at LiMn₂O₄ cathode in Li₂SO₄ aqueous solution is similar to that reported in the organic electrolytes. The charge transfer resistance (R_ct), warburg resistance, double layer capacitance and chemical diffusion coefficient (DLi+) vary with potentials during de-insertion/insertion processes. R_ct is lowest at the CV peak potentials and the important kinetic parameter, DLi+ exhibits two distinct minima at potentials corresponding to CV peaks during de-insertion–insertion and it was found to be between 10⁻⁸ and 10⁻¹⁰ cm² s⁻¹during lithium de-insertion/insertion processes.     

Optimization of Aspergillus niger Fermentation for the Production of Glucose Oxidase

A number of nutritional factors influencing glucose oxidase (EC 1.1.3.4) production by Aspergillus niger NCIM 545 were studied. The synthesis of glucose oxidase by A. niger was investigated in two steps using submerged fermentation at 30 ± 2 °C and 180 rpm for 96 h. Primarily, nutritional components were selected by one-factor-at-a-time method, and the significance of each component with respect to glucose oxidase production was identified by Plackett–Burman design (seven variables including six nutritional viz. sucrose, sodium nitrate, peptone, calcium carbonate, magnesium sulfate, and potassium dihydrogen phosphate, and one dummy or unassigned variable were studied with eight experiments). In the second step, concentration of most significant factors and their interaction were studied with response surface methodology (central composite design). Each variable in the design was studied at five different levels, with all variables taken at a central coded value of zero. Considerable amount of glucose oxidase was produced from A. niger species with sucrose as the carbon source, sodium nitrate as the inorganic nitrogen source, and peptone as the organic nitrogen source. Glucose oxidase activity increased remarkably by 28.93 fold (from 0.00993 to 0.29 U ml⁻¹) with CaCO₃-supplemented media. The outcome of Plackett–Burman design showed CaCO₃, peptone, and MgSO₄ as significant parameters. Further optimization using a three-factor central composite design with 20 experiments increased yield of glucose oxidase from 0.29 to 2.05 U ml⁻¹ (sevenfold) with a decrease in cultivation time from 96 to 72 h.     

Meso-scale studies in fracture of concrete: A numerical simulation

The fracture behaviour of concrete is complex due to highly heterogeneous nature of the material. The heterogeneity of concrete manifests itself at various scales. At mesoscale, the presence of aggregates influences the strength of concrete by developing a zone of weakness in the form of aggregate–matrix interface. These lead to an increased distributed micro-cracking and enhances the energy absorption capacity of the material. The energy absorption capacity of structure is dependent not only on material properties but also on structural geometry and loading conditions. The present work attempts to identify the material and structural parameters that influence the overall behaviour, by using discrete numerical modelling of the material at mesoscale. Lattice modelling, a technique to model the heterogeneity using lattice elements is used to study the fracture behaviour of the material. Effect of aggregate volume fraction, specimen thickness and depth on the global behaviour is studied.     

Modeling Multithreaded Applications Using Petri Nets

Since most modern computing systems contain multiple processing elements, applications are relying on multithreaded programming techniques that allow a program to execute multiple tasks concurrently to take advantage of the processing capabilities. Multithreaded programs are more difficult to design and test because of the nondeterministic execution orders and synchronization among the threads. Different approaches can be used to test Multithreaded Applications. In our approach we use Petri nets to represent the key elements of interactions among threads to identify potential problems such as race conditions, lost signals, and deadlocks. A tool called C2Petri has been developed which converts C-Pthreads programs to the equivalent Petri net model. This tool helps verification of Pthread-based programs. At present the tool has limited capabilities and we hope to expand the capabilities of our tool in the near future.     

Hydrochloric acid leaching of nickel sulfide precipitates

Nickel sulfide precipitates produced by the AMAX Acid Leach Process for oxide nickel ores were leached in hydrochloric acid. The effects of process variables such as temperature, acid concentration, stoichiometric excess of HCl, gas sparging and heat treatment of feed were investigated. The nickel leachability was found to be in the 60–80% range. Chemical and mineralogical examination of the leach residues indicated the presence of NiS₂. This higher nickel sulfide is insoluble in hydrochloric acid, and its presence hinders the leaching of NiS. Several methods are suggested to reduce the sulfur content in order to attain complete dissolution. The thermodynamics and kinetics of nickel sulfide leaching are briefly discussed.     

Towards a generic distributed and collaborative digital manufacturing

A framework for distributed manufacturing is proposed to facilitate collaborative product development and production among geographically distributed functional agents using digitalized information. Considering the complexity of products created in a distributed manufacturing scenario, it often requires close collaborations among a number of facilities. In this research work, various functional agents, such as the manufacturability evaluation agent (MEA), manufacturing resource agent (MRA), process-planning agent (PPA), manufacturing scheduling agent (MSA), shop floor agent (SFA), fault diagnosis agent (FDA), etc., can interact coherently for distributed manufacturing. With specific agents having unique functionalities, a manufacturing managing agent (MMA) acts as the centre of this distributed manufacturing system. The MMA agent assists the specific agents’ to work seamlessly and also to collaborate closely with the participating agents. In this way, the production cycle of a part can be optimized from product design to final manufacturing since all the production procedures are considered logically and every procedure is correlated. The agent language based on the knowledge query manipulation language (KQML) includes many pre-defined performatives that ease the participating agents to carry out their tasks intelligently by interpreting commands from one another. Additionally, to ensure the adaptiveness and upgradeability of the system, the internal structure of each functional agent that is based on JATLite is modularized into several components, including a communication interface, central work engine, knowledge base pool, and input/output modifier for possible future methodology enhancements.     

Resolving the Micropayment Problem

Cryptography-based alternatives are the most appropriate long-term solution to the micropayment problem, especially compared to the business solution of restructuring transaction fees. We acknowledge that the business solution is easier to deploy in the short term. Cryptography-based solutions face tremendous deployment challenges: they need more market testing, they significantly change payment-ecosystem processes, their legal implications are unclear, and they require new kinds of devices and processes for merchants. Nonetheless, the long-term payoff of investing in such sound solutions are be tremendous     

A Novel Electroless Process for Embedding a Thin Film Resistor on the Benzocyclobutene Dielectric

To realize embedded resistors on multilayer benzocyclobutene (BCB) either on-chip or on-board, a low-cost large format electroless process for deposition of NiP and NiWP thin-film resistors using both low-temperature (25°C) and high-temperature (90°C) baths has been developed. The electroless process exhibits uniform resistor thickness in the submicron range and offers low profile and excellent adhesion to the BCB dielectric layer. The resistor films also act as a seed layer for direct electroplating of copper traces. The NiP alloys can also be tailored to a variable temperature coefficient of resistance (TCR) with different alloy compositions. The electroless process can be adopted in the PCB manufacturing industries with no additional investment. This article is the first report on electroless plated thin film resistors on low loss BCB dielectric.