bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface‐Grafted Semiconductor Layer Prepared by Surface Initiated Ring‐Opening Polymerization of L‐Lysine NCA Derivatives
Authors: Fu Wenxin , Sun Kai , Li Zhibo 
Published: April 2014

AbstractAsymmetric and symmetric L‐lysine N‐carboxylic anhydrides based on perylene bisimide derivatives were successfully synthesized and grafted onto silicon wafers via surface‐initiated ring‐opening polymerization. The grafted n‐type semiconductor film was flat and compact, and its thickness could be tuned by variation of the polymerization conditions.
Hierarchically Porous Nickel Oxide Nanosheets Grown on Nickel Foam Prepared by One‐Step In Situ Anodization for High‐Performance Supercapacitors
Authors: Yang Li , Qian Lei , Tian Xianqing , Li Jing , Dai Jianyuan , Guo Yong , Xiao Dan 
Published: April 2014

AbstractPorous NiO nanosheets are successfully grown on nickel foam substrate through an in situ anodization by using molten KOH as the electrolyte. High‐purity NiO is directly obtained by this one‐step method without any subsequent treatment. The obtained NiO supported on nickel foam is used as a binder‐free electrode for a supercapacitor and its pseudocapacitive behavior has been investigated by cyclic voltammetry and galvanostatic charge–discharge tests in a 6 M aqueous solution of KOH. Electrochemical data demonstrates that this binder‐free electrode possesses ultrahigh capacitance (4.74 F cm−2 at 4 mA cm−2), excellent rate capability, and cycling stability. After 1000 cycles, the areal capacitance value is 9.4 % lower than the initial value and maintains 85.4 % of the maximum capacitance value.
Regulation of mitochondrial morphology by lipids
Authors: Ha Elizabeth E.‐J. , Frohman Michael A. 
Published: April 2014

AbstractAlthough great progress has been made in identifying key protein factors that regulate mitochondrial morphology through mediating fission and fusion, signaling lipids are increasingly being recognized as important in the process as well. We review here roles that have been proposed for the signaling and bulk lipids cardiolipin, phosphatidic acid, lysophosphatidic acid, diacylglycerol, and phosphatidylethanolamine and the enzymes that generate or catabolize them in the regulation of mitochondrial morphology in yeast and mammals. Mutations in some of these enzymes are causal in a number of disease settings, highlighting the significance of controlling the lipid environment in this setting. © 2014 BioFactors, 40(4):419–424, 2014
Metabolic responses of CHO cells to limitation of key amino acids
Authors: Duarte Tiago M. , Carinhas Nuno , Barreiro Laura C. , Carrondo Manuel J. T. , Alves Paula M. , Teixeira Ana P. 
Published: April 2014

ABSTRACTChinese hamster ovary (CHO) cells are the predominant host for production of therapeutic glycoproteins. In particular, the glutamine‐synthetase (GS) expression system has been widely used in the biopharmaceutical industry for efficient selection of high‐yielding clones. However, much remains unclear on how metabolic wiring affects culture performance. For instance, asparagine and serine have been observed to be the largest nitrogen sources taken up by GS‐CHO cells, but their roles in biosynthesis and energy generation are poorly understood. In this work, a comprehensive profiling of extracellular metabolites coupled with an analysis of intracellular label distributions after 1‐13C‐pyruvate supplementation were used to trace metabolic rearrangements in different scenarios of asparagine and serine availability. The absence of asparagine in the medium caused growth arrest, and was associated with a dramatic increase in pyruvate uptake, a higher ratio of pyruvate carboxylation to dehydrogenation and an inability for de novo asparagine synthesis. The release of ammonia and amino acids such as aspartate, glutamate, and alanine were deeply impacted. This confirms asparagine to be essential for these GS‐CHO cells as the main source of intracellular nitrogen as well as having an important anaplerotic role in TCA cycle activity. In turn, serine unavailability also negatively affected culture growth while triggering its de novo synthesis, confirmed by label incorporation coming from pyruvate, and reduced glycine and formate secretion congruent with its role as a precursor in the metabolism of one‐carbon units. Overall, these results unfold important insights into GS‐CHO cells metabolism that lay a clearer basis for fine‐tuning bioprocess optimization. Biotechnol. Bioeng. 2014;111: 2095–2106. © 2014 Wiley Periodicals, Inc.
Addition of citrate to Acidithiobacillus ferrooxidans cultures enables precipitate‐free growth at elevated pH and reduces ferric inhibition
Authors: Li Xiaozheng , Mercado Roel , Kernan Timothy , West Alan C. , Banta Scott 
Published: April 2014

ABSTRACTAcidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that is important in biomining and other biotechnological operations. The cells are able to oxidize inorganic iron, but the insolubility and product inhibition by Fe3+ complicates characterization of these cultures. Here we explore the growth kinetics of A. ferrooxidans in iron‐based medium in a pH range from 1.6 to 2.2. It was found that as the pH was increased from 1.6 to 2.0, the maintenance coefficient decreased while both the growth kinetics and maximum cell yield increased in the precipitate‐free, low Fe2+ concentration medium. In higher iron media a similar trend was observed at low pH, but the formation of precipitates at higher pH (2.0) hampered cell growth and lowered the specific growth rate and maximum cell yield. In order to eliminate ferric precipitates, chelating agents were introduced into the medium. Citric acid was found to be relatively non‐toxic and did not appear to interfere with iron oxidation at a maximum concentration of 70 mM. Inclusion of citric acid prevented precipitation and A. ferrooxidans growth parameters resumed their trends as a function of pH. The addition of citrate also decreased the apparent substrate saturation constant (KS) indicating a reduction in the competitive inhibition of growth by ferric ions. These results indicate that continuous cultures of A. ferrooxidans in the presence of citrate at elevated pH will enable enhanced cell yields and productivities. This will be critical as these cells are used in the development of new biotechnological applications such as electrofuel production. Biotechnol. Bioeng. 2014;111: 1940–1948. © 2014 Wiley Periodicals, Inc.
NADPH‐dependent reductive biotransformation with Escherichia coli and its pfkA deletion mutant: Influence on global gene expression and role of oxygen supply
Authors: Siedler Solvej , Bringer Stephanie , Polen Tino , Bott Michael 
Published: April 2014

ABSTRACTAn Escherichia coli ΔpfkA mutant lacking the major phosphofructokinase possesses a partially cyclized pentose phosphate pathway leading to an increased NADPH per glucose ratio. This effect decreases the amount of glucose required for NADPH regeneration in reductive biotransformations, such as the conversion of methyl acetoacetate (MAA) to (R)‐methyl 3‐hydroxybutyrate (MHB) by an alcohol dehydrogenase from Lactobacillus brevis. Here, global transcriptional analyses were performed to study regulatory responses during reductive biotransformation. DNA microarray analysis revealed amongst other things increased expression of soxS, supporting previous results indicating that a high NADPH demand contributes to the activation of SoxR, the transcriptional activator of soxS. Furthermore, several target genes of the ArcAB two‐component system showed a lower mRNA level in the reference strain than in the ΔpfkA mutant, pointing to an increased QH2/Q ratio in the reference strain. This prompted us to analyze yields and productivities of MAA reduction to MHB under different oxygen regimes in a bioreactor. Under anaerobic conditions, the specific MHB production rates of both strains were comparable (7.4 ± 0.2 mmolMHB h−1 gcdw−1) and lower than under conditions of 15% dissolved oxygen, where those of the reference strain (12.8 mmol h−1 gcdw−1) and of the ΔpfkA mutant (11.0 mmol h−1 gcdw−1) were 73% and 49% higher. While the oxygen transfer rate (OTR) of the reference strain increased after the addition of MAA, presumably due to the oxidation of the acetate accumulated before MAA addition, the OTR of the ΔpfkA strain strongly decreased, indicating a very low respiration rate despite sufficient oxygen supply. The latter effect can likely be attributed to a restricted conversion of NADPH into NADH via the soluble transhydrogenase SthA, as the enzyme is outcompeted in the presence of MAA by the recombinant NADPH‐dependent alcohol dehydrogenase. The differences in respiration rates can explain the suggested higher ArcAB activity in the reference strain. Biotechnol. Bioeng. 2014;111: 2067–2075. © 2014 Wiley Periodicals, Inc.
Computer AIDS for chemical engineering education: An assessment of CACHE—1971–1992
Authors: Seider Warren D. 
Published: April 2014

AbstractSince its inception in 1971, the Computer Aids for Chemical Engineering Education (CACHE) Corporation has concentrated on promoting cooperation among universities, industry, and government in the development and distribution of computer‐related and/or technology‐based educational aids for the chemical engineering profession. This article assesses the success of several projects designed to provide aids for individual courses, as well as for a broader segment of the curriculum. The projects include: (1) the provision of 125 computer assignments for the core courses; (2) the preparation of teaching materials for, and the distribution of, Monsanto's FLOWTRAN program for use in the design courses; (3) the preparation of PC modules for many courses, leading to the Michigan project on the Development of Innovative Engineers, the Washington project on Graphical Computer Aids for fluid flow and reaction in the design of chemical reactors, and the Purdue project on Laboratory Modules; and (4) the development of the MICROCACHE courseware delivery system. Also considered are the CACHE recommendations concerning the minimum requirements for computing in the undergraduate curriculum, presented to the AIChE Education and Accreditation Committee. The CACHE Corporation has facilitated several research conferences, the impact of which is assessed.
Simulation of electromagnetic radiation and scattering using a finite difference‐time domain technique
Authors: Li K. , Tassoudji M. A. , Shin R. T. , Kong J. A. 
Published: April 2014

AbstractThe finite difference‐time domain (FD‐TD) technique is applied to the solution of Maxwell's equations. A computer program, which can be used to simulate and study numerous electromagnetic phenomena, is developed and implemented on an IBM 386 compatible personal computer. The FD‐TD technique is a useful tool for students in electromagnetics. The technique is flexible and can be applied to many basic EM scattering and radiation problems. Because field solutions are found as a function of time, visualization of the propagation of the EM fields is possible. The FD‐TD technique is implemented for a two‐dimensional rectangular grid in conjunction with a second‐order absorbing boundary condition. Both E‐ and H‐field polarizations are analyzed. Finite objects consisting of dielectric, magnetic and conducting materials, and perfectly conducting infinite ground planes are modeled. Plane wave and line current sources are implemented. In addition to the capability of animating the propagation of the EM fields, radiation and scattering patterns can be generated.
Discretization of partial differential equations for computer evaluation
Authors: Fazarinc Zvonko 
Published: April 2014

AbstractPhysics described by partial differential equations is difficult to visualize. Computer solutions of such equations supported with dynamic graphic displays are therefore of high interest to educators and scientists [1]. Translation of partial differential equations into formats understood by computers is beset with complexity and pitfalls. This article explores a direct method for deriving the relevant algorithms from physics itself and illustrates the approach with examples in propagation and diffusion. The resulting algorithms are cast into C‐language.
Computer software for structural engineering education: FATPAK II—student edition
Authors: Fleming John F. 
Published: April 2014

AbstractFATPAK II—Student Edition is a general purpose computer package for the linear elastic analysis of two‐ and three‐dimensional frames and trusses. It will run on an IBM PC or compatible system. It was developed for student use in structural analysis and design courses. The primary purpose for its development was to permit students to investigate the response of structural systems under a variety of conditions. The results of the analysis can be expressed in both printed and graphical form.
Object‐oriented animation system for seismic response of multistory structures
Authors: Ho Hsing‐Hua , Adeli Hojjat 
Published: April 2014

AbstractVisualizing the dynamic behavior of structures under earthquake loading is a challenge for students taking structural dynamics and earthquake engineering courses. A prototype animation system was developed for visualizing the dynamic response of multistory structures subjected to earthquake excitations, using the object‐oriented programming paradigm and implemented in Microsoft Windows and Borland C++ on a 33 MHz 80486‐based personal computer. At present, the animation system is limited to two‐dimensional multistory frames with rigid floors. The input can be any accelerogram (ground acceleration record) due to any real or artificial earthquake. The user of the system can change the input parameters of the structure or select the ground acceleration record and view their effect on the dynamic behavior of the structure. This object‐oriented animation model is an effective courseware or interactive computer tool that may be used in teaching structural dynamics and earthquake engineering courses.
TEACON—a simulator for computer‐aided teaching of process control
Authors: de Azevedo S. Feyo , Oliveira F. , Cardoso A. Capelo 
Published: April 2014

Abstract“TEACON—TEAching CONtrol” is a PC‐based package for computer‐aided teaching of digital control of Single Input‐Single Output (SISO) systems. A large variety of processes and control actions is possible. The program simulates systems in “real time” or faster than “real time.” Process and control parameters can be changed on‐line during runs. Set‐point and process load can also vary according to predefined functions. The program computes the ISE, IAE, and ITAE indexes, allowing studies of controller tuning and performance. Other characteristics which enhance the simulation of real systems are the saturation of sensors and controller at 0 and 100%, the ability to superimpose noises on the measurements, and the possibility of defining dead‐times associated with the measurements and with the process.
ARRAY: Educational software for antenna patterns and synthesis
Authors: Romeu Jordi , Pous Rafael , Pujol Ramon 
Published: April 2014

AbstractThis article describes the main features of an educational program developed as a teaching aid for an undergraduate antenna course. The key feature of this software with regard to existing antenna array software (1–4) is the importance given to graphic presentation of the results. Aside from a detailed description of the program, a general overview of the curriculum and certain experiences with the use of the program are presented.
Introduction to multigrid using matlab
Authors: Haupt Randy L. , Haupt Sue Ellen 
Published: April 2014

AbstractMultigrid is a powerful numerical tool for solving a variety of engineering problems. We motivate the use of the technique, introduce its theoretical basis, provide a step‐by‐step procedure for its use, and present examples. We include a tutorial MATLAB program, which allows the user to experiment with the technique for a typical problem.
Interactive beam analysis program for engineering education
Authors: Gramoll Kurt C. 
Published: April 2014

AbstractThis article describes an interactive graphic beam analysis program for undergraduate engineering education that has been used at the Georgia Institute of Technology. The program is fully mouse‐ and menu‐driven, and the results, moment, shear, and deflection diagrams, are graphically displayed. The development objectives of the program and how the program has been used effectively to increase the learning and understanding of indeterminate beam structures are discussed. Practical experience with the program in two elementary structures courses is also reviewed. The article shows how graphically oriented programs can be beneficial to the education of first‐year engineering students by allowing them to perform “what‐if” design scenarios. The program is structured to minimize the time the instructor needs to spend on demonstration in the classroom. The program is free to all educational institutions.
Three‐phase induction motor simulation for teaching purposes
Authors: Faiz Jawad , Sharifian M. B. B. 
Published: April 2014

AbstractSpecially developed computer software for a three‐phase induction motor simulation for an undergraduate course is presented. The computation time of the simulation method used is reasonably short: about 29% of the CPU time required by the ordinary fifth‐order model. Using the software tools developed, students can effectively perform analysis of induction motors at various modes of operation. The software is viewed on the color display of a personal computer, and each part of the program may be activated by means of a user‐friendly graphics editor.
Interactive visualizations of electromagnetic fields inside waveguides and cavities using the WGC program
Authors: Elsherbeni Atef Z. , Taylor Clayborne D. 
Published: April 2014

AbstractA personal computer program has been developed to provide an interactive procedure for visualizing the electromagnetic fields inside seven different types of cylindrical wave‐guides and cavities. In this program, both transverse and longitudinal field components are presented graphically, using a color contour map and/or vectors. The user can interactively observe the effect of changing any of the physical or electrical parameters on the resulting electric and magnetic field distribution in any specified plane cut. The mathematic expressions of the field components are derived from the classical solution of the wave equation using the separation of variables technique.
Spreadsheet solution to an initial value problem using the runge‐kutta‐fehlberg method
Authors: Kharab A. 
Published: April 2014

AbstractThe objective of this article is to demonstrate the computational capabilities of spreadsheets to solve an initial value problem for ordinary differential equations using the Runge‐Kutta‐Fehlberg method. Through user macros, the numeric solution is obtained with considerably less programming effort than high‐level programming languages such as Fortran. A macro program using Lotus 123 is developed, and numeric results are given.
Numerical experiments in fluid mechanics with a tank and draining pipe
Authors: Brauner Neima , Shacham Mordechai 
Published: April 2014

AbstractThis article emphasizes the use of interactive simulation packages as an integral part of the problem solution in both engineering education and practice. A homework problem in fluid mechanics is presented. Using numerical simulation of a tank and draining pipe arrangement, the students were required to find the effect of the viscosity of the fluid, draining pipe length, and initial fluid level in the tank on the initial draining velocity and the time required for complete draining of the tank. The results obtained were surprising and unexpected, encouraging the students to investigate further the model equations in order to find an explanation for the unexpected system behavior.
A software tool for electromagnetic analysis of power system elements using finite difference method
Authors: Faiz Jawad , Dadgari Ali 
Published: April 2014

AbstractThis article presents, in a simple manner, a mathematical basis of finite difference method and describes a sample computer program to support the teaching of electromagnetic fields in an undergraduate course. The program is used to demonstrate the flux contours of magnetic fields inside the cores with different configurations. This can help students in their first contact with electromagnetic field analysis problems and in power system elements, and can also help them develop their required software experience based on our procedure.
Graphical visualization of missile–target air‐to‐air engagements: An educational tool for designing and evaluating missile guidance and control systems
Authors: Rodriguez Armando A. , Aguilar Ricardo 
Published: April 2014

AbstractThis article describes a user‐friendly C/C++/Windows‐based program which simulates and graphically displays a Bank‐to‐Turn (BTT) missile in pursuit of an evading target. Traditionally, students and practicing engineers must conduct extensive simulations to develop insight about such a complex “system.” In this article, an educational PC graphics program which significantly expedites this process is described. The program is organized into three modules: (1) A program‐user interface provides interactive mouse‐keyboard‐driven pull‐down menus to adjust engagement parameters. (2) A simulation module generates engagement data from a system of nonlinear differential equations modeling the missile, the autopilot, various guidance laws, and target maneuvers. (3) A graphics module uses the data to update the encounter on the screen. The program can be linked with MATLAB macros for purposes of analysis. A help/instruct facility assists users with program features and concepts. Sample missile‐target engagements are presented to demonstrate the utility of the program as an educational tool and as a tool for the analysis, design, and evaluation of missile guidance and control systems. In short, the program has proven itself as a useful educational tool for students studying feedback and control systems and as an excellent vehicle for introducing students to modeling, simulation, and graphical visualization of dynamical systems.
Computer tool for minimizing logic functions
Authors: Kabalan Karim Y. , El‐Hajj Ali , Fakhreddine Souheir , Smari Waleed S. 
Published: April 2014

AbstractThis article presents a computer package that can be used in the minimization of logic functions. The package is a practical tool for teaching digital design and other related courses. The inputs to this program are the number of switching variables and the switching function to be minimized. The function is introduced in the form of minterms or in the form of a switching expression. The user may choose any of three methods to perform the minimization process: algebraic manipulation using theorems, the Karnaugh map, and the Quine—McCluskey methods. The program starts the minimization gradually until an optimal expression is reached. The user can visualize the steps of the procedure used in the particular minimization technique. Thus, the package provides several possibilities for minimizing certain functions and then selects the best approach among them which employs the minimum number of gates for the gate‐level drawing of the function.