bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced reduction of single‐wall carbon nanotube cytotoxicity in vitro: Applying a novel method of arginine functionalization
Authors: Charbgoo Fahimeh , Behmanesh Mehrdad , Nikkhah Maryam 
Published: October 2014

AbstractBiomedical applications of carbon nanotubes (CNTs) have attracted a lot of attention in recent years. However, the applications of CNTs in these fields of research are challenged by some properties such as their insolubility and cytotoxicity. To improve their solubility in physiological solutions or to reduce cytotoxicity, a variety of engineered biologically active molecules through functionalization processes are being designed. Application of appropriate biomolecules has become an interesting research area these days from both fundamental and application standpoints. In the present report, arginine amino acids were used for single‐wall carbon nanotubes (SWCNTs) functionalization because of their bulky and polar side chain. The efficiency of SWCNTs conjugation with arginine was demonstrated by Fourier transform infrared and Raman spectroscopies and Sakaguchi assay. Cytotoxicity of functionalized CNTs was investigated by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay on three different cell lines. Results indicated that functionalization of SWCNTs with arginine reduced their cytotoxicity extremely and hence make them more appropriate for biomedical applications. Moreover, it was concluded that sensitivity to CNT cytotoxicity depends on the type of tissue and cell line. Here, an impressive and novel method for biological functionalization of CNTs has been introduced.
Examination of alternate codon bias solutions for expression and purification of recombinant mechano‐growth factor in Escherichia coli
Authors: Feng Jianguo , Wan Rongxue , Yi Qian , He Ling , Yang Li , Tang Liling 
Published: October 2014

AbstractMechano‐growth factor (MGF), an alternative splicing variant of insulin‐like growth factor‐1 (IGF‐1) gene, promotes cell proliferation and inhibits cell differentiation. It also plays an important role in tumor development. It is important to optimize the production process and achieve MGF protein because there is no commercial MGF protein available. In this study, the human MGF gene is cloned into pGEX‐4T‐1 and the recombinant human MGF (rhMGF) protein could be expressed in Rosetta (DE3) by isopropyl β‐d‐1‐thiogalactopyranoside induction but not in BL21 (DE3). Mutation from rare codons to Escherichia coli preferred ones is performed. We obtain MGF(Mut54–56) and MGF(Mut‐total) fragments through site‐directed mutagenesis and overlapping PCR. Both pGEX‐4T‐1/MGF(Mut54–56)‐ and pGEX‐4T‐1/MGF(Mut‐total)‐transformed BL21 (DE3) can be induced to express rhMGF protein. To optimize the production technology, expression and purification of rhMGF are analyzed and compared in Rosetta (DE3) and BL21 (DE3). Results indicate that rhMGF expression in BL21 (DE3) is significantly higher than that in Rosetta (DE3). The protein yield of pGEX‐4T‐1/MGF(Mut‐total) in BL21 (DE3) is higher than that of pGEX‐4T‐1/MGF(Mut54–56). We test the biological activity of MGF protein purified by affinity chromatography in C2C12 cell line and find that rhMGF promotes cell proliferation significantly. In conclusion, we establish a method to produce rhMGF economically with high biological activity in BL21 (DE3).
Interactive Hangman teaches amino acid structures and abbreviations
Authors: Pennington Britney O. , Sears Duane , Clegg Dennis O. 
Published: October 2014

AbstractWe developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one‐letter abbreviations by modifying the familiar game of “Hangman.” Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying structures, hints to the answers were written in “amino acid sentences” for the students to translate. Students were required to draw the structure of the corresponding letter they wished to guess on a whiteboard. Each student received a reference sheet of the structures and abbreviations, but was required to draw from memory when guessing a letter. Preassessments and postassessments revealed a drastic improvement in the students' ability to recognize and draw structures from memory. This activity provides a fun, educational game to play in biochemistry discussion sections or during long incubations in biochemistry laboratories. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(6):495–500, 2014.
Learning about being a scientist from the vitamin B12 structure collaboration
Authors: White Susan A. 
Published: October 2014

AbstractThis historical note reviews the work that resulted in the publication of the structure of Vitamin B12. The collaborations and resulting friendships that developed during this time made a strong impression on the author and encouraged her to pursue a scientific career. 2014 by The International Union of Biochemistry and Molecular Biology, 42(6):507–509, 2014.
Planning approaches to constraint‐aware navigation in dynamic environments
Authors: Ninomiya Kai , Kapadia Mubbasir , Shoulson Alexander , Garcia Francisco , Badler Norman 
Published: October 2014

AbstractPath planning is a fundamental problem in many areas, ranging from robotics and artificial intelligence to computer graphics and animation. Although there is extensive literature for computing optimal, collision‐free paths, there is relatively little work that explores the satisfaction of spatial constraints between objects and agents at the global navigation layer. This paper presents a planning framework that satisfies multiple spatial constraints imposed on the path. The type of constraints specified can include staying behind a building, walking along walls, or avoiding the line of sight of patrolling agents. We introduce two hybrid environment representations that balance computational efficiency and search space density to provide a minimal, yet sufficient, discretization of the search graph for constraint‐aware navigation. An extended anytime dynamic planner is used to compute constraint‐aware paths, while efficiently repairing solutions to account for varying dynamic constraints or an updating world model. We demonstrate the benefits of our method on challenging navigation problems in complex environments for dynamic agents using combinations of hard and soft, attracting and repelling constraints, defined by both static obstacles and moving obstacles. Copyright © 2014 John Wiley & Sons, Ltd.
Solvent‐Free Syntheses of Hierarchically Porous Aluminophosphate‐Based Zeolites with AEL and AFI Structures
Authors: Jin Yinying , Chen Xian , Sun Qi , Sheng Na , Liu Yan , Bian Chaoqun , Chen Fang , Meng Xiangju , Xiao Feng‐Shou 
Published: October 2014

AbstractDevelopment of sustainable routes for synthesizing aluminophosphate‐based zeolites are very important because of their wide applications. As a typical sustainable route, solvent‐free synthesis of zeolites not only decreases polluted wastes but also increases product yields. Systematic solvent‐free syntheses of hierarchically porous aluminophosphate‐based zeolites with AEL and AFI structures is presented. XRD patterns and SEM images show that these samples have high crystallinity. N2 sorption isotherm tests show that these samples are hierarchically porous, and their surface areas are comparable with those of corresponding zeolites from hydrothermal route. Chosen as an example, catalytic oxidation of ethylbenzene with O2 shows that cobalt substituted APO‐11 from the solvent‐free route (S‐CoAPO‐11) is more active than conventional CoAPO‐11 from hydrothermal route owing to the sample hierarchical porosity.
Disassembly‐Driven Fluorescence Turn‐on of Polymerized Micelles by Reductive Stimuli in Living Cells
Authors: Niko Yosuke , Arntz Youri , Mely Yves , Konishi Gen‐ichi , Klymchenko Andrey S. 
Published: October 2014

AbstractStimuli‐response nanoparticles have emerged as powerful tools for imaging and therapeutic applications. Ideally, they should be assembled from biodegradable materials featuring small size and cooperative response to biological stimuli that trigger particle disassembly and release of an active molecule that could be readily monitored in situ. A concept is developed that consists of organic nanoparticles, assembled from fluorescent amphiphiles and polymerized with a redox‐cleavable cross‐linker. We obtained 20 nm nanoparticles bearing self‐quenched Nile Red dye residues, which can disassemble in living cells into highly fluorescent molecular units owing to an external or internal reductive stimulus. The obtained results pave the way to new stimuli‐responsive nanomaterials for applications in background‐free imaging as well as in drug delivery, as the concept can be further extended to other active molecules including drugs and to cross‐linkers cleavable by other biological stimuli.
Host–Guest Interactions in ExBox4+
Authors: Das Ranjita , Chattaraj Pratim Kumar 
Published: October 2014

AbstractThe host–guest interaction between poly aromatic hydrocarbon/azine and the newly synthesized ExBox4+ complex is studied with the help of density functional theory. The solvent‐phase interaction energy is found to decrease with gradual substitution of methine groups (CH) from the six‐membered ring of guest molecules with N atoms in the resultant azine@ExBox4+ complex. The nature of the binding interaction is studied with the help of newly developed noncovalent interaction (NCI) plot program package along with energy decomposition analysis and charge decomposition analysis. The interactions are mostly π‐type van der Waals interactions.
Diameter Selection of Carbon Nanotubes in Polymer/SWCNT Nanowire Arrays Fabricated by Template Wetting
Authors: Domingo Concepción , García‐Gutiérrez Mari‐Cruz 
Published: October 2014

AbstractArrays of polymer/SWCNT (single‐wall carbon nanotube) nanowires supported on a residual nanocomposite film are prepared by melt wetting using porous anodic aluminum oxide (AAO) as a template. The aggregation parameter of SWCNTs extracted from the analysis of their Raman radial breathing modes gives the highest value for native SWCNTs, indicating that they tend to organize into bundles giving rise to a high degree of aggregation. However, the lowest value achieved at the interface between the nanocomposite film and the nanoarray is explained considering that the forces acting during infiltration are able to disrupt the SWCNT bundles inducing nanotube dispersion. In addition, scanning the nanoarrays along the nanowires length by Raman microscopy has shown a diameter selection of SWCNTs by the AAO membrane. The results reported in this work reveal that it is possible to fabricate arrays of nanowires with homogeneous SWCNT distribution along tens of microns, optimizing nanotube dispersion.
Effect of Bromine Complexing Agents on the Performance of Cation Exchange Membranes in Second‐Generation Vanadium Bromide Battery
Authors: Winardi Suminto , Poon Grace , Ulaganathan Mani , Parasuraman Aishwarya , Yan Qingyu , Wai Nyunt , Lim Tuti Mariana , Skyllas–Kazacos Maria 
Published: October 2014

AbstractThe effect of bromine complexing agents, N‐ethyl‐N‐methyl‐morpholinium bromide (MEM) and N‐ethyl‐N‐methyl‐pyrrolidinium bromide (MEP) on the performance of different perfluorinated cation exchange membranes, ChiNaf and VF11, is assessed in the G2 vanadium bromide battery (V/Br). It is noted that in the absence of MEM and MEP, the thicker ChiNaf (50 μm) membrane shows a higher energy efficiency at a current density of 20 mA cm−2. A preliminary test of ChiNaf at two different concentration ratios of MEM and MEP evaluated at 4 mA cm−2 shows that a mixture of 0.19 M MEM and 0.56 M MEP provides a slightly higher cell efficiency than the other tested compositions. However, better cell performance is obtained with the VF11 (25 μm) membrane at 4 mA cm−2 using 0.19 M MEM and 0.56 M MEP. Further studies using VF11 with a mixture of 0.19 M MEM and 0.56 M MEP at 20 mA cm−2 provide direct evidence that the addition of MEM+MEP lowers the cell performance through a reduction in voltage efficiency. The increased membrane resistance after the introduction of MEM and MEP marks the formation of an organic layer after bromine reacts with MEM and MEP and is deposited onto the membrane.
A distributed interference alignment algorithm using min‐maxing strategy
Authors: El‐Absi M. , El‐Hadidy M. , Kaiser T. 
Published: October 2014

AbstractInterference alignment is a joint‐transmission strategy that significantly increases the sum rate of interference channels at high signal‐to‐noise ratios (SNRs). The recent iterative interference alignment approaches are incapable of guaranteeing the best sum‐rate performance with the increase of the SNR amongst different K‐user interference channels, especially at high SNR regime. In this paper, a new interference alignment algorithm is developed to improve the sum‐rate performance of K‐user multi‐input multi‐output (MIMO) and multi‐carrier interference channels by minimising the interference leakage and maximising the desired power concurrently, which is called by min‐maxing strategy. For a K‐user MIMO interference channel, we design transmit precoding matrices and receive decoding matrices through an efficient iterative algorithm based on min‐maxing strategy in a distributed way, in which each receiver maximises the desired signal power, whereas it preserves the minimum leakage interference as a constraint. This optimisation problem is reformulated and relaxed into a standard semidefinite programming form. The convergence of the proposed algorithm is proved as well. Furthermore, a simplified min‐maxing algorithm is proposed for rank‐deficient interference channels to achieve the targeted performance with less complexity. The numerical simulations show that the proposed algorithm proffers significant sum‐rate improvement in K‐user MIMO interference channels compared with the existing algorithms at high SNR regime. Moreover, the simplified algorithm matches the optimal performance in the systems of rank‐deficient channels. Finally, the developed min‐maxing algorithm has been extended to K‐user multi‐carrier interference channels, which outperform the previous approaches in terms of sum rate in several scenarios. Copyright © 2014 John Wiley & Sons, Ltd.
A Stochastic Dynamic Program for Valuing Options on Futures
Authors: Ayadi Mohamed A. , Ben‐Ameur Hatem , Kirillov Tymur , Welch Robert 
Published: October 2014

AbstractWe propose a stochastic dynamic program (SDP) for valuing options on stock‐index futures. SDP accommodates European‐ as well as American‐style options, and price limits on the underlying futures contracts. Our numerical investigation shows convergence, robustness, and efficiency. SDP presents some advantages and disadvantages with respect to the binomial tree and finite differences, and stands as a viable alternative to these classic numerical methodologies for option valuation. Our empirical investigation, which focuses on American options on the S&P 500 futures contract, is almost perfect for implicit volatilities, but somewhat mitigated for historical volatilities. In volatile markets, we recommend short time windows for the volatility estimation step. © 2013 Wiley Periodicals, Inc. Jrl Fut Mark 34:1185–1201, 2014
Investigation of Icon Design and Touchable Area for Effective Smart Phone Controls
Authors: Im Youngjae , Kim Taeil , Jung Eui S. 
Published: October 2014

AbstractAs the full‐touch screen is being implemented in more smart phones, controllability of touch icons need to be considered. Previous research focused on recommendations for absolute key size. However, the size of tactual input on touch interface is not precisely equal to the icon size. This study aims to determine the suitable touchable area to improve touch accuracy. In addition, there was an investigation into the effect of layout (3 × 4, 4 × 5, 5 × 6, and 6 × 8) and icon ratio (0.5, 0.7, and 0.9). To achieve these goals, 40 participants performed a set of serial tasks on the smart phone. Results revealed that the layout and icon ratio were statistically significant on the user response: input offset, hit rate, task completion time, and preference. The 3 × 4 and 4 × 5 layouts were shown to have better performance. The icon ratio of 0.9 was shown to have greater preference. Furthermore, the hit rate (proportion of correct input) of touchable area was estimated through the bivariate normal distribution of input offset. The hit rate could vary, depending on the size of touchable area, which is a rectangle that yields a specific hit rate. A derivation procedure of the touchable area was proposed to guarantee the desirable hit rate. Meanwhile, the locations of the central region indicated a pattern of vertical touch and showed better performance. The users felt more difficulty when approaching the edge of the frame. The results of this study could be used in the design of touch interfaces for mobile devices.
Teaching, Learning, and Sharing Openly Online
Authors: Ian O'Byrne W. , Roberts Verena , LaBonte Randy , Graham Lee 
Published: October 2014

AbstractOpen learning is becoming a critical focus for K‐12 technology‐supported programs as the importance of digital literacy and digital freedoms for all learners grows. This article describes current open learning policy, open educational resources and potential implications for open practice and ends with suggestions for future research in open learning. The column situates this examination in the context of current opportunities and challenges that impact open learning in educational spaces.
Deletion of Connexin43 in Osteoblasts/Osteocytes Leads to Impaired Muscle Formation in Mice
Authors: Shen Hua , Grimston Susan , Civitelli Roberto , Thomopoulos Stavros 
Published: October 2014

ABSTRACT

It is well-established that muscle forces are necessary for bone development as well as proper bone modeling and remodeling. Recent work has also suggested that bone acts as an endocrine organ that can influence the development of other organs. Connexin43 (Cx43), a gap junction protein that transduces mechanical signals, is an important determinant of cortical bone modeling. Using an osteoblast/osteocyte–specific ablation of the Cx43 gene (Gja1) driven by the 2.3-kb Col1α1 promoter (cKO) in the mouse, in this study we confirmed reduced cortical bone thickness and density with expanded bone marrow cavity in the cKO humerus. Surprisingly, Gja1 deletion in bone cells also affected skeletal muscle development, resulting in lower fast muscle weight, grip strength, and maximum absolute and specific tetanic forces (60% to 80%, 85%, and 50%, respectively, of WT mice). The normally fast twitch extensor digitorum longus (EDL) muscle exhibited increased slow twitch fibers in cKO mice. These muscle defects were accompanied by a 40% to 60% reduction in mRNA abundance for genes encoding osteocalcin in the humerus, relative to WT mice. Accordingly, both carboxylated and undercarboxylated isoforms of osteocalcin were reduced by over 30% in the circulation of cKO mice. Moreover, the active, undercarboxylated isoform of osteocalcin (glu-OC) promoted myotube formation in C2C12 myoblast cultures, and glu-OC injections to cKO mice rescued EDL muscle cross-sectional area and grip strength in vivo. These findings demonstrate that Cx43 in osteoblasts/osteocytes indirectly modulates skeletal muscle growth and function, potentially via an endocrine effect of glu-OC. © 2014 American Society for Bone and Mineral Research.
Enhancement of the Effects of Exfoliated Carbon Nanofibers by Bone Morphogenetic Protein in a Rat Femoral Fracture Model
Authors: Miyazaki Masashi , Toyoda Masahiro , Yoshiiwa Toyomi , Kawano Masanori , Kaku Nobuhiro , Tsumura Hiroshi 
Published: October 2014

ABSTRACTExfoliated carbon nanofibers (ExCNFs) are expected to serve as excellent scaffolds for promoting and guiding bone‐tissue regeneration. We aimed to enhance the effects of ExCNFs with bone morphogenetic proteins (BMPs) and examine their feasibility and safety in clinical applications using a rat femoral fracture model. Group I (n = 16) animals were implanted with control MedGEL. Group II (n = 17) animals were implanted with MedGEL containing ExCNFs. Group III (n = 15) animals were implanted with MedGEL containing 1 μg rhBMP‐2. Group IV (n = 15) animals were implanted with MedGEL containing 1 μg rhBMP‐2 and ExCNFs. The rats were euthanized after 6 weeks, and their fractured femurs were explanted and assessed by manual palpation, radiographs, and high‐resolution microcomputerized tomography (micro‐CT); the femurs were also subjected to biomechanical and histological analysis. The fusion rates in Group IV (73.3%) were considerably higher than those in Groups I (25.0%), II (52.9%), and III (46.7%). The results demonstrated the enhancement of the bone repair effects of ExCNFs by BMP in a rat femoral fracture model. Our results suggest that the enhancement of the effects of ExCNFs by BMP makes the combination a possible attractive therapy for various orthopedic surgeries. © 2014 Orthopaedic Research Society. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:185–192, 2015.
Combined effect of high hydrostatic pressure and mild heat treatments on pectin methylesterase (PME) inactivation in comminuted orange
Authors: Tejada‐Ortigoza Viridiana , Escobedo‐Avellaneda Zamantha , Valdez‐Fragoso Aurora , Mújica‐Paz Hugo , Welti‐Chanes Jorge 
Published: October 2014

AbstractBACKGROUNDComminuted orange, a product obtained by grinding the juice and peel and used to formulate beverages, has a high pectin methylesterase (PME) activity; thus the inactivation of this enzyme is necessary to avoid quality losses related to cloud loss. The use of high hydrostatic pressure (HHP) and mild temperature allows inactivation of enzymes with minimal quality changes. This work aimed to evaluate the effect of pressure, mild temperature and time of treatment, including come‐up and holding time, on the inactivation of PME in comminuted orange, and to apply kinetic and response surface models (RSM) to predict residual PME activity (A/A0).RESULTSDuring come‐up time in treatments at 68 °C, the higher the pressure, the lower was the A/A0 obtained. At 550 MPa/68 °C/10 min the lowest residual activity value was obtained (15.6%). A/A0 was well adjusted to the RSM, and a first‐order kinetic model was applied to describe the inactivation of PME. In general, the higher the pressure, the lower was the A/A0 reached, as the increasing values of k from 3.5 × 10−2 to 55.5 × 10−2 min−1 indicated. Activation volume (Va) values ranging from −9.2 to −17.7 cm3 mol−1, and activation energies (Ea) between 50.0 and 68.2 kJ mol−1 were calculated.CONCLUSION550 MPa/68 °C/10 min, 350 MPa/68 °C/10 min and 450 MPa/56 °C/10 min treatments were satisfactory (∼84% inactivation) to inactivate PME. A first‐order kinetic model was applied to describe PME inactivation, and the resulting A/A0 adjusted to the RSM. In addition, linearized Arrhenius and Eyring equations were well fitted in order to obtain Ea and Va, respectively. © 2014 Society of Chemical Industry