bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diffusivities of dichloromethane in poly(lactide‐co‐glycolide)
Authors: Foss Willard R. , Anderl Jeffrey N. , Clausi Amber L. , Burke Paul A. 
Published: February 2009

AbstractDiffusion of dichloromethane in poly(lactide‐co‐glycolide) (PLGA), the rate‐limiting step in the later stages of drying of microparticles formed in common encapsulation processes, was studied by the step‐change sorption technique in a dynamic vapor sorption apparatus. Methods were developed to create films of polymer with the appropriate thicknesses for accurate diffusion determination over a wide range of solvent composition. Mutual diffusivities were measured at 5, 25, and 35°C from 10 to 70 wt % solvent. Values range from 2 × 10−10 m2/s at high solvent compositions to as low as 1 × 10−13 m2/s at solvent compositions just above the glass transition of the mixture. Equilibrium sorption isotherms were measured in the same apparatus and agreed favorably with Flory‐Huggins theory using a value of χ = 0.31. The glass transition temperatures of the system were measured over the range of 0–11 wt % solvent content by modulated differential scanning calorimetry. The composition dependence was fit to the Fox equation, which estimated values of the pure polymer and the solvent Tg to be 39.3 and −131°C, respectively. These values, along with the diffusivity data, were used to deduce the free‐volume parameters specific to PLGA. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of isomery in drug release from poly(butyl monoitaconate‐co‐acrylamide) hydrogels
Authors: Katime Issa , Canjura O. , Cesteros L. C. , Mendizábal E. , Mendizábal Adriana P. 
Published: February 2009

AbstractIn this work, we report the synthesis and characterization of poly(butyl monoitaconate‐co‐acrylamide) hydrogels to be used as drug release agents. Four isomers of butanol were used to synthesize the hydrogels. The influence of butyl monoitaconate isomery on swelling behavior, Young's and compression moduli, cross‐linking density and molar mass between cross‐links are reported. It was found that by increasing butyl ramification, equilibrium degree of swelling, and the time for reaching swelling equilibrium decreases. Cross‐linking density, Young's and compression moduli increases as butyl ramification increases. The release of theophylline and aminophylline drugs used in therapy for respiratory diseases were studied and it was found that theophylline was released faster than aminophylline © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Evaluation of molecular orientation in injection molded parts with microscale features by Raman spectroscopy
Authors: Murakami Osamu , Yamada Kazushi , Kotaki Masaya , Hamada Hiroyuki 
Published: February 2009

AbstractMolecular orientation of polycarbonate (PC) in injection‐molded parts with microscale features was characterized by means of polarized Raman spectroscopy, and the relationship between microstructure and replication was discussed. The microscale feature size of continuous v‐groove was 20 μm in depth and 50 μm in width. PC injection‐molded parts were molded with various molding conditions. The molecular orientation distribution along flow direction on the cross‐section of molding parts were evaluated by the intensity ratio of the bands at 635 to 703 cm−1 (I635/I703) in the Raman spectra. Molecular orientation along the flow direction inside the v‐groove was higher than that of the core and the opposite surface region. In particular, the highest molecular orientation was at the surface of the v‐groove. Among the injection molding conditions, the mold temperature showed significant effect on the molecular orientation and replication. Higher mold temperature caused high replication and low molecular orientation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The relative influence of advice from human experts and statistical methods on forecast adjustments
Authors: Önkal Dilek , Goodwin Paul , Thomson Mary , Gönül Sinan , Pollock Andrew 
Published: February 2009

AbstractDecision makers and forecasters often receive advice from different sources including human experts and statistical methods. This research examines, in the context of stock price forecasting, how the apparent source of the advice affects the attention that is paid to it when the mode of delivery of the advice is identical for both sources. In Study 1, two groups of participants were given the same advised point and interval forecasts. One group was told that these were the advice of a human expert and the other that they were generated by a statistical forecasting method. The participants were then asked to adjust forecasts they had previously made in light of this advice. While in both cases the advice led to improved point forecast accuracy and better calibration of the prediction intervals, the advice which apparently emanated from a statistical method was discounted much more severely. In Study 2, participants were provided with advice from two sources. When the participants were told that both sources were either human experts or both were statistical methods, the apparent statistical‐based advice had the same influence on the adjusted estimates as the advice that appeared to come from a human expert. However when the apparent sources of advice were different, much greater attention was paid to the advice that apparently came from a human expert. Theories of advice utilization are used to identify why the advice of a human expert is likely to be preferred to advice from a statistical method. Copyright © 2009 John Wiley & Sons, Ltd.
Effect of 100 mT homogeneous static magnetic field on [Ca2+]c response to ATP in HL‐60 cells following GSH depletion
Authors: Belton Michelle , Prato Frank S. , Rozanski Camilla , Carson Jeffrey J.L. 
Published: February 2009

AbstractCalcium is an important molecule in a number of biological systems. Often these systems are signal transduction cascades involving molecules such as ATP. ATP activates second messengers which can interact with ion channels on the endoplasmic/sarcoplasmic reticulum resulting in the emptying of the intracellular calcium stores and an increase in cytosolic free calcium concentration ([Ca2+]c). Changes in [Ca2+]c can be influenced by external factors such as a static magnetic field (SMF). One hypothesis suggests that a SMF affects the cells through the radical pair mechanism. By reducing the number of antioxidant molecules like glutathione (GSH), the proportion of free radicals in the cells is increased and may lead to a greater probability of a biological response to a SMF. The purpose of this study was to determine if the [Ca2+]c response to ATP was affected by depletion of GSH by diethylmaleate (DEM) and the absence or presence of a 100 mT homogeneous SMF. Undifferentiated HL‐60 cells were loaded with fura‐2 AM. [Ca2+]c was measured in real time using a ratiometric fluorescence spectroscopy system. Various (DEM) ranging from 1 to 15 mM were added to deplete GSH. Cells were either exposed to sham or magnetic field (100 mT) for 13 min (780 s) and challenged with 1 µM ATP. The data show that [Ca2+]c was elevated following treatment with DEM with greater [Ca2+]c at higher [DEM]. The [Ca2+]c response to ATP was decreased as the DEM concentration increased. However, there was no effect of a 100 mT SMF on the average [Ca2+]c peak following ATP activation or the full width at half maximum (FWHM) of the [Ca2+]c response and recovery after ATP activation. Bioelectromagnetics 30:322–329, 2009 © 2009 Wiley‐Liss, Inc.
Shadows of complexity: what biological networks reveal about epistasis and pleiotropy
Authors: Tyler Anna L. , Asselbergs Folkert W. , Williams Scott M. , Moore Jason H. 
Published: February 2009

AbstractPleiotropy, in which one mutation causes multiple phenotypes, has traditionally been seen as a deviation from the conventional observation in which one gene affects one phenotype. Epistasis, or gene–gene interaction, has also been treated as an exception to the Mendelian one gene–one phenotype paradigm. This simplified perspective belies the pervasive complexity of biology and hinders progress toward a deeper understanding of biological systems. We assert that epistasis and pleiotropy are not isolated occurrences, but ubiquitous and inherent properties of biomolecular networks. These phenomena should not be treated as exceptions, but rather as fundamental components of genetic analyses. A systems level understanding of epistasis and pleiotropy is, therefore, critical to furthering our understanding of human genetics and its contribution to common human disease. Finally, graph theory offers an intuitive and powerful set of tools with which to study the network bases of these important genetic phenomena.
The ‘kinetochore maintenance loop’—The mark of regulation?
Authors: Brown William R. A. , Xu Zheng‐yao 
Published: February 2009

AbstractKinetochores can form and be maintained on DNA sequences that are normally non‐centromeric. The existence of these so‐called neo‐centromeres has posed the problem as to the nature of the epigenetic mechanisms that maintain the centromere. Here we highlight results that indicate that the amount of CENP‐A at human centromeres is tightly regulated. It is also known that kinetochore assembly requires sister chromatid cohesion at mitosis. We therefore suggest that separation or stretching between the sister chromatids at metaphase reciprocally determines the amount of centromere assembly in the subsequent interphase. This reciprocal relationship forms the basis of a negative feedback loop that could precisely control the amount of CENP‐A and faithfully maintain the presence of a kinetochore over many cell divisions. We describe how the feedback loop would work, propose how it could be tested experimentally and suggest possible components of its mechanism.
Dinoflagellate mitochondrial genomes: stretching the rules of molecular biology
Authors: Waller Ross F. , Jackson Christopher J. 
Published: February 2009

AbstractMitochondrial genomes represent relict bacterial genomes derived from a progenitor α‐proteobacterium that gave rise to all mitochondria through an ancient endosymbiosis. Evolution has massively reduced these genomes, yet despite relative simplicity their organization and expression has developed considerable novelty throughout eukaryotic evolution. Few organisms have reengineered their mitochondrial genomes as thoroughly as the protist lineage of dinoflagellates. Recent work reveals dinoflagellate mitochondrial genomes as likely the most gene‐impoverished of any free‐living eukaryote, encoding only two to three proteins. The organization and expression of these genomes, however, is far from the simplicity their gene content would suggest. Gene duplication, fragmentation, and scrambling have resulted in an inflated and complex genome organization. Extensive RNA editing then recodes gene transcripts, and trans‐splicing is required to assemble full‐length transcripts for at least one fragmented gene. Even after these processes, messenger RNAs (mRNAs) lack canonical start codons and most transcripts have abandoned stop codons altogether.
Using embryonic stem cells to form a biological pacemaker via tissue engineering technology
Authors: Ou Dong‐Bo , Lang Hong‐Juan , Chen Rui , Liu Xiong‐Tao , Zheng Qiang‐Sun 
Published: February 2009

AbstractBiological pacemakers can be achieved by various gene‐based and cell‐based approaches. Embryonic stem cells (ESCs)‐derived pacemaker cells might be the most promising way to form biological pacemakers, but there are challenges as to how to control the differentiation of ESCs and to overcome the neoplasia, proarrhythmia, or immunogenicity resulting from the use of ESCs. As a potential approach to solve these difficult problems, tissue‐engineering techniques may provide a precise control on the different cell components of multicellular aggregates and the forming of a construct with‐defined architectures and functional properties. The combined interactions between ESC‐derived pacemaker cells, supporting cells, and matrices may completely reproduce pacemaker properties and result in a steady functional unit to induce rhythmic electrical and contractile activities. As ESCs have a high capability for self‐renewal, proliferation, and potential differentiation, we hypothesize that ESCs can be used as a source of pacemaker cells for tissue‐engineering applications and the ambitious goal of biological cardiac pacemakers may ultimately be achieved with ESCs via tissue‐engineering technology.
Development and characterization of a tissue engineered pancreatic substitute based on recombinant intestinal endocrine L‐cells
Authors: Bara Heather , Sambanis Athanassios 
Published: February 2009

AbstractA tissue engineered pancreatic substitute (TEPS) consisting of insulin‐producing cells appropriately designed and encapsulated to support cellular function and prevent interaction with the host may provide physiological blood glucose regulation for the treatment of insulin dependent diabetes (IDD). The performance of agarose‐based constructs which contained either a single cell suspension of GLUTag‐INS cells, a suspension of pre‐aggregated GLUTag‐INS spheroids, or GLUTag‐INS cells on small intestinal submucosa (SIS), was evaluated in vitro for total cell number, weekly glucose consumption and insulin secretion rates (GCR and ISR), and induced insulin secretion function. The three types of TEPS studied displayed similar number of cells, GCR, and ISR throughout 4 weeks of culture. However, the TEPS, which incorporated SIS as a substrate for the GLUTag‐INS cells, was the only type of TEPS tested which was able to retain the induced insulin secretion function of non‐encapsulated GLUTag‐INS cells. Though improvements in the expression level of GLUTag‐INS cells and/or the number of viable cells contained within the TEPS are needed for successful treatment of a murine model of IDD, this study has revealed a potential method for promoting proper cellular function of recombinant L‐cells upon incorporation into an implantable three‐dimensional TEPS. Biotechnol. Bioeng. 2009;103: 828–834. © 2009 Wiley Periodicals, Inc.
Scale‐up analysis for a CHO cell culture process in large‐scale bioreactors
Authors: Xing Zizhuo , Kenty Brian M. , Li Zheng Jian , Lee Steven S. 
Published: February 2009

AbstractBioprocess scale‐up is a fundamental component of process development in the biotechnology industry. When scaling up a mammalian cell culture process, it is important to consider factors such as mixing time, oxygen transfer, and carbon dioxide removal. In this study, cell‐free mixing studies were performed in production scale 5,000‐L bioreactors to evaluate scale‐up issues. Using the current bioreactor configuration, the 5,000‐L bioreactor had a lower oxygen transfer coefficient, longer mixing time, and lower carbon dioxide removal rate than that was observed in bench scale 5‐ and 20‐L bioreactors. The oxygen transfer threshold analysis indicates that the current 5,000‐L configuration can only support a maximum viable cell density of 7 × 106 cells mL−1. Moreover, experiments using a dual probe technique demonstrated that pH and dissolved oxygen gradients may exist in 5,000‐L bioreactors using the current configuration. Empirical equations were developed to predict mixing time, oxygen transfer coefficient, and carbon dioxide removal rate under different mixing‐related engineering parameters in the 5,000‐L bioreactors. These equations indicate that increasing bottom air sparging rate is more efficient than increasing power input in improving oxygen transfer and carbon dioxide removal. Furthermore, as the liquid volume increases in a production bioreactor operated in fed‐batch mode, bulk mixing becomes a challenge. The mixing studies suggest that the engineering parameters related to bulk mixing and carbon dioxide removal in the 5,000‐L bioreactors may need optimizing to mitigate the risk of different performance upon process scale‐up. Biotechnol. Bioeng. 2009;103: 733–746. © 2009 Wiley Periodicals, Inc.
Teaching mobile and wireless information systems development in engineering courses
Authors: Licea Guillermo , Aguilar Leocundo , Juárez J. Reyes , Martínez Luis G. 
Published: February 2009

AbstractMADEE (Mobile Application Development and Execution Environment) is a platform that supports the development of small and middle size mobile and wireless information systems for handheld devices. MADEE allows a student to develop applications faster and easier than using conventional development tools. This study presents the results and experience obtained using MADEE to support the introduction of mobile and wireless information systems development concepts in the context of computer engineering courses. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 261–268, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20251
A high‐performance and well‐manageable distributed measurement laboratory with an object‐oriented approach
Authors: Lai Yuan‐Cheng , Lin Jian‐Wei 
Published: February 2009

AbstractThe distributed measurement laboratory (DML) can provide users with the capability of performing and practicing their experiments in a transparent manner on remote instruments located in different geographic areas and connected with a wide area network. In this article, we propose a high‐performance and well‐manageable DML, named HPWM, which is characterized by three main novel features: (1) using .NET Remoting to provide better network performance and having scalable and extendable architecture; (2) using Asynchronous JavaScript and XML (AJAX) to provide an efficient and lightweight Graphic User Interface (GUI) without browser plug‐ins; and (3) offering adequate management functionalities to well manage users and instruments and establishing their relationships. The software structure used for developing HPWM is also described. Finally, HPWM has been tested in the academic and industrial education and has shown its correctness and effectiveness. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 18: 344–355, 2010; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae.20265
Glucose deprivation increases nuclear DNA repair protein Ku and resistance to radiation induced oxidative stress in human cancer cells
Authors: Li Jie , Ayene Roashan , Ward Kathleen M. , Dayanandam Eswarkumar , Ayene Iraimoudi S. 
Published: February 2009

AbstractRecent studies have indicated that nutrient deprivation particularly glucose may play a major role in tumor cell tolerance to a generally oxidative stress environment in solid tumors. Here, we studied the impact of glucose deprivation on the response of human colon (HT29) and prostate (DU145) cancer cells to γ radiation. A significant decrease in intracellular glucose level was observed in glucose deprived cells as measured by bioreductive assay. The survival of HT29 and DU145 were increased by 30 and 100% respectively when these cells were exposed to γ radiation in the absence of glucose compared to that in the presence of glucose. In glucose depleted medium, glutathione (GSH), a free radical scavenger, content remained the same, and showed no correlation with the radiation resistance induced by glucose deprivation. Glucose regulated protein78 (GRP78), a stress response survival protein, was not significantly increased in cells deprived of glucose for 4 h compared to those cells in glucose. DNA repair protein Ku, which is known to play a major role in cellular resistance to radiation, was significantly increased in glucose deprived cancer cells that showed enhanced radiation resistance. These results have demonstrated, for the first time, that glucose deprivation mediated stress increased the expression of nuclear Ku and resistance to radiation induced oxidative stress in human cancer cells. The additional resistance caused by glucose deprivation in cancer cells has clinical significance since solid tumors are known to have low level of glucose due to diffusion limited blood supply and higher metabolic activity. Copyright © 2009 John Wiley & Sons, Ltd.
Successful embolization of a left ventricular pseudoaneurysm after perventricular ventricular septal defect device closure
Authors: Breinholt John P. , Rodefeld Mark D. , Hoyer Mark H. 
Published: February 2009

AbstractPerventricular device closure has become an important management adjunct for ventricular septal defects deemed inoperable and difficult to address in the catheterization laboratory. Complications directly related to the procedure are rarely reported, and all have been manifest in the periprocedural period. We present the case of a 6‐week‐old boy who underwent perventricular closure of a muscular ventricular septal defect and had a left ventricle pseudoaneurysm identified 10 months later during catheterization to close residual septal defects. We describe the subsequent percutaneous coil embolization of the pseudoaneurysm and clinical follow‐up. © 2009 Wiley‐Liss, Inc.
Use of Selenium to Detect Mercury in Water and Cells: An Enhancement of the Sensitivity and Specificity of a Seleno Fluorescent Probe
Authors: Tang Bo , Ding Baiyu , Xu Kehua , Tong Lili 
Published: February 2009

AbstractSeleno fluorescent probe: An organoselenium fluorescent probe (FSe‐1) for mercury was designed based on the irreversible deselenation mechanism. FSe‐1 exhibits an ultrahigh selectivity and sensitivity for Hg2+ detection only for reactive selenium atom sites, due the strong affinity between Se and Hg. Furthermore, the new probe has been successfully used for imaging mercury ions in RAW 264.7 cells (a mouse macrophage cell line; see figure).magnified imageInspired by the antitoxic function of selenium towards heavy‐metal ions, we designed an organoselenium fluorescent probe (FSe‐1) for mercury. The reaction of FSe‐1 and Hg2+ is an irreversible deselenation mechanism based on the selenophilic character of mercury. FSe‐1 exhibits an ultrahigh selectivity and sensitivity for Hg2+ detection only for reactive selenium atom sites due to the strong affinity between Se and Hg. The experimental results proved that FSe‐1 was selective for Hg2+ ions over other relevant metal ions and bioanalytes, and also showed an enhancement in sensitivity of up to 1.0 nM, which is lower than the current Environmental Protection Agency standard for drinking water. Furthermore, the new probe has been successfully applied to the imaging of mercury ions in RAW 264.7 cells (a mouse macrophage cell line) with high sensitivity and selectivity.
Palladium‐Catalyzed Intramolecular Hydroamination of Allenes Coupled to Aerobic Alcohol Oxidation
Authors: Qiu Shuifa , Wei Yunyang , Liu Guosheng 
Published: February 2009

AbstractTaking the air! A PdII‐catalyzed intramolecular hydroamination of allenes coupled to alcohol oxidation has been developed. This reaction is performed by using a nitrogen‐based ligand under aerobic conditions, under which the molecular oxygen is used as the terminal oxidant for the reoxidation of Pd0 species to complete the catalytic cycle.magnified image
Cyclometalated Platinum(II) Complexes as Highly Sensitive Luminescent Switch‐On Probes for Practical Application in Protein Staining and Cell Imaging
Authors: Wu Peng , Wong Ella Lai‐Ming , Ma Dik‐Lung , Tong Glenna So‐Ming , Ng Kwan‐Ming , Che Chi‐Ming 
Published: February 2009

AbstractProtein‐staining platinum: The luminescent switch‐on characteristic of the platinum(II) complex can be utilized for staining a series of proteins in sodium dodecyl sulfate‐polyarcylamide gels, to give emissive gel images directly under UV light (see figure). The detection sensitivity for BSA protein is down to 6.0 ng, revealing potential practical applications of luminescent platinum(II) complexes in the luminescent signaling of biomolecules.magnified image