bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accurate determination of calcium stearate by atomic absorption spectrophotometric method in polymer
Authors: Farajzadeh Mir Ali , Ravandi Mahboobe Ghorbani , Ranji Ali , Feyz Elham 
Published: February 2008

AbstractIn this study, an atomic absorption spectrophotometric method is presented for the determination of calcium stearate in polymer samples after their pyrolysis. Samples of polymers were burned in an electrical furnace at 500°C. After thermal degradation of polymeric matrix, 1M HCl solution was added to dissolve the residue. Then the absorbance of solution was measured by an atomic absorption spectrophotometer at calcium atomic line. This method has an extent linear dynamic range (0.4–50 mg/L) with a limit of detection (LOD) 0.1 mg/L in solution. LOD of the proposed method in polymer sample using 0.5 g sample size is 15 ppm as calcium stearate. Some effective parameters such as time and temperature of pyrolysis and concentration of hydrochloric acid were studied. Finally, this method was successfully applied for the determination of calcium stearate content of standard and real polymers. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of N‐polyethereal polypyrroles and their application for the preconcentration of rare earth ions
Authors: Köksel Bahar , Cihaner Atilla , Kaya Murat , Volkan Mürvet , Önal Ahmet M. 
Published: February 2008

AbstractConducting polymers containing polyether pseudocages (PI, PII, PIII) have been synthesized via chemical oxidation of 1,5‐bis(1,1‐pyrrole)‐3‐oxabutane (MI), 1,8‐bis(1,1‐pyrrole)‐3,6‐dioxahexane (MII), and 1,11‐bis(1,1‐pyrrole)‐3,6,9‐trioxaundecane (MIII) using anhydrous FeCl3 in CHCl3. Because as obtained polymer resins did not give any response toward any cations, they were reduced (undoped) using chemical reducing agents. Tetrabutylammonium hydroxide was found to be more effective in undoping to obtain more reproducible and reusable polymer resins. The undoped polymer resins were tried in the extraction of rare earth metal ions from the aqueous medium. Among them, only PIII resin removes La(III), Eu(III) and Yb(III) and can be employed for the preconcentration of these metal ions. For batch extraction of La(III), Eu(III) and Yb(III) at neutral pH values, percent recoveries of 98.0 ± 1.0, 90.7 ± 1.4, 87.3 ± 4.0, respectively, has been obtained. The sorption capacity is found as 1.3 mg of La(III) per gram of PIII resin. The PIII resin could be reused at least five times without significant change in its sorption capacity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis, characterization, and self‐assembly of cationic coumarin side‐chain polymer
Authors: Zhang Chuanzhi , Liang Ruiyuan , Jiang Chunxia , Chen Deben , Zhong Anyong 
Published: February 2008

AbstractIn this study, the synthesis of a novel cationic coumarin‐containing polymer (C‐CPA) was presented. C‐CPA was examined optically using photoluminescence (PL) spectroscopy. The optical data suggested that they were promising blue‐emitting materials mainly due to the coumarin chromophore on the side chain. Moreover, the synthesized cationic polymer was suitable for layer‐by‐layer electrostatic self‐assembly thin film deposition from dilute polymer solution and multilayers were fully characterized by UV–vis spectroscopy, PL spectroscopy and atomic force microscope. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Effect of crystalline microstructure near the particle/matrix interface on the toughening of syndiotactic polystyrene/polyamide‐6 blends
Authors: Il Kang Byung , Nair Sobha V. , Yang Hoichang , Lim Ho Sun , Lee Dae Ho , Cho Kilwon 
Published: February 2008

AbstractToughening behavior of semicrystalline polymers was investigated using syndiotactic polystyrene (sPS)/polyamide 6(PA‐6) blends compatibilized with maleic‐anhydride functionalized poly (styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene) SEBS‐MA triblock copolymer. The effect of interparticle distance and crystal microstructure near the particle/matrix interface of the blends were studied. The morphology studies revealed that the size and interparticle distance of the dispersed PA‐6 particles decreased with increasing SEBS‐MA concentration. sPS/PA‐6 blends exhibited sharp brittle‐ductile transitions at a critical interparticle distance of 0.25 μm. With the increase of the compatibilizer concentration beyond a certain level, it was observed that the further addition resulted in decreased impact strength. This could be attributed to the formation of a separate phase in the matrix by the additional SEBS added. The TEM studies showed that when the interparticle distance is below 0.25 μm, the matrix ligaments between the inclusions will be filled with well‐oriented crystalline material of reduced plastic resistance. From DSC and X‐ray diffraction studies of model thin films, it was found that the fraction of small and imperfect crystallites near the particle/matrix interface increased with decreasing interparticle distance. This resulted in decreased yield stress of the whole matrix with increasing concentration of SEBS‐MA accompanied by changes in the fracture mode from brittle to tough. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Tuning the particle size and charge density of the crosslinked polystyrene particles
Authors: Arunbabu Dhamodaran , Sannigrahi Arindam , Jana Tushar 
Published: February 2008

AbstractWe report the synthesis of charged spherical colloidal particles of poly [styrene‐(co‐2‐propene sulfonic acid)] crosslinked with divinylbenzene by emulsion polymerization. The effects of concentration of both the emulsifier and initiator on the polymerization, particle size, and charge density are studied. The particle size is found to be dependent on both the emulsifier and initiator concentration and their power dependencies are different. Below critical micelle concentration (CMC), the particle size varies significantly within a small range of emulsifier concentration. In contrast, particle size decrease is not very pronounced at the heterogeneous (micellar) particle nucleation regime where the emulsifier concentration is well above of the CMC. The power dependencies of the number of particles on surfactant concentration are explained in the light of conversion–time profile of the polymerization. The surface charge density of the colloidal particles also varies with both the emulsifier and initiator concentration. Both the particle size and charge density show an inverse relation with the molecular weight of the polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Degradation behavior of linear low‐density polyethylene films containing prooxidants under accelerated test conditions
Authors: Roy P. K. , Surekha P. , Rajagopal C. , Choudhary V. 
Published: February 2008

AbstractThis article reports the results of studies on the photooxidative and thermooxidative degradation of linear low‐density polyethylene (LLDPE) in the presence of cobalt stearate. Various amounts of cobalt stearate (0.1–0.9% w/w) blended with LLDPE and films of 70 ± 5 μ thickness were prepared by a film‐blowing technique. The films were subjected to xenon arc weathering and air‐oven aging tests (at 70°C) for extended time periods. We followed the chemical and physical changes induced as a result of aging by monitoring changes in the mechanical properties (tensile strength and elongation at break), carbonyl index, morphology (scanning electron microscopy), melt flow index, and differential scanning calorimetry crystallinity. Cobalt stearate was highly effective in accelerating the photodegradation of LLDPE films at concentrations greater than 0.2% w/w. The kinetic parameters of degradation, as determined by nonisothermal thermogravimetric analysis, were estimated with the Flynn–Wall–Ozawa isoconversion technique, which was subsequently used to determine the effect of cobalt stearate on the theoretical lifetime of LLDPE. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Melatonin is as Effective as Testosterone in the Prevention of Soleus Muscle Atrophy Induced by Castration in Rats
Authors: Öner Jale , Öner Hakan , Sahin Zeliha , Demir Ramazan , Üstünel İsmail 
Published: February 2008

AbstractThe purpose of this experiment was to compare the weight, insulin‐like growth factor‐I (IGF‐I) expression, and ultrastructure of the soleus muscle in growing castrated rats treated with testosterone or melatonin. In this study, adult male Wistar albino rats were used. The groups were arranged as sham, castrated, and testosterone‐ or melatonin‐injected groups after castration. The soleus muscle samples were fixed in Bouin's solution for immunohistochemistry, and in 2.5% gluteraldehyde in 0.1 M phosphate buffer (pH 7.4). Whereas castration reduced the soleus weight and fiber diameter, testosterone and melatonin administration increased them. IGF‐I immunostaining observed in the satellite cells and periphery of the myofibers was least intense in the castrated group. Strong staining of IGF‐I was observed in the testosterone‐ and melatonin‐administered groups. The ultrastructure of the soleus muscle in castrated animals showed the important ultrastructural modifications related to degeneration. In these groups, degenerative mitochondria, glycogen clusters under the sarcolemma, irregular Z lines, and loss of lamina externa were observed. The ultrastructure of myofibrils in the testosterone‐ and melatonin‐injected groups was similar to that in sham groups in view of structure. In conclusion, we suggest that melatonin is as effective as testosterone in the prevention of atrophy induced by castration through the IGF‐I axis. Anat Rec, 291:448–455, 2008. © 2008 Wiley‐Liss, Inc.
Information quality work organization in wikipedia
Authors: Stvilia Besiki , Twidale Michael B. , Smith Linda C. , Gasser Les 
Published: February 2008

AbstractThe classic problem within the information quality (IQ) research and practice community has been the problem of defining IQ. It has been found repeatedly that IQ is context sensitive and cannot be described, measured, and assured with a single model. There is a need for empirical case studies of IQ work in different systems to develop a systematic knowledge that can then inform and guide the construction of context‐specific IQ models. This article analyzes the organization of IQ assurance work in a large‐scale, open, collaborative encyclopedia—Wikipedia. What is special about Wikipedia as a resource is that the quality discussions and processes are strongly connected to the data itself and are accessible to the general public. This openness makes it particularly easy for researchers to study a particular kind of collaborative work that is highly distributed and that has a particularly substantial focus, not just on error detection but also on error correction. We believe that the study of those evolving debates and processes and of the IQ assurance model as a whole has useful implications for the improvement of quality in other more conventional databases.
Construction of Chemical‐Responsive Supramolecular Hydrogels from Guest‐Modified Cyclodextrins
Authors: Deng Wei , Yamaguchi Hiroyasu , Takashima Yoshinori , Harada Akira 
Published: February 2008

AbstractA methodology for preparing supramolecular hydrogels from guest‐modified cyclodextrins (CDs) based on the host–guest and hydrogen‐bonding interactions of CDs is presented. Four types of modified CDs were synthesized to understand better the gelation mechanism. The 2D ROESY NMR spectrum of β‐CD‐AmTNB (Am=amino, TNB=trinitrobenzene) reveals that the TNB group was included in the β‐CD cavity. Pulsed field gradient NMR (PFG NMR) spectroscopy and AFM show that β‐CD‐AmTNB formed a supramolecular polymer in aqueous solution through head‐to‐tail stacking. Although β‐CD‐AmTNB did not produce a hydrogel due to insufficient growth of supramolecular polymers, β‐CD‐CiAmTNB (Ci=cinnamoyl) formed supramolecular fibrils through host–guest interactions. Hydrogen bonds between the cross‐linked fibrils resulted in the hydrogel, which displayed excellent chemical‐responsive properties. Gel‐to‐sol transitions occurred by adding 1‐adamantane carboxylic acid (AdCA) or urea. 1H NMR and induced circular dichroism (ICD) spectra reveal that AdCA released the guest parts from the CD cavity and that urea acts as a denaturing agent to break the hydrogen bonds between CDs. The hydrogel was also destroyed by adding β‐CD, which acts as the competitive host to reduce the fibrils. Furthermore, the gel changed to a sol by adding methyl orange (MO) as a guest compound, but the gel reappeared upon addition of α‐CD, which is a stronger host for MO.
Major congenital malformations following prenatal exposure to serotonin reuptake inhibitors and benzodiazepines using population‐based health data
Authors: Oberlander Tim F. , Warburton William , Misri Shaila , Riggs Wayne , Aghajanian Jaafar , Hertzman Clyde 
Published: February 2008

AbstractBACKGROUND: To determine a population‐based incidence of congenital anomalies following prenatal exposure to serotonin reuptake inhibitor (SRI) antidepressants used alone and in combination with a benzodiazepines (BZ). METHODS: Population health data, maternal health, and prenatal prescription records were linked to neonatal records, representing all live births (British Columbia, Canada, N=119,547) during a 39‐month period (1998–2001). The incidence and risk differences (RD) for major congenital anomalies (CA) and congenital heart disease (CHD), including ventricular and atrial septal defects (VSD, ASD), from infants of mothers treated with an SRI alone, a benzodiazepine (BZ) alone, or SRI+BZ in combinationcompared to outcomesno exposure. RESULTS: Risk for a CA or CHD did increase following combined SRI+BZ exposure compared with no exposure. However, using a weighted regression model, controlling for maternal illness characteristics, combination therapy risk remained significantly associated only with CHD. The risk for an ASD was higher following SRI monotherapy compared with no exposure, after adjustment for maternal covariates. Dose/day was not associated with increased risk. CONCLUSIONS: Infants exposed to prenatal SRIs in combination with BZs had a higher a incidence of CHD compared to no exposure, even after controlling for maternal illness characteristics. SRI monotherapy was not associated with an increased risk for major CA, but was associated with an increased incidence of ASD. Risk was not associated with first trimester medication dose/day. Birth Defects Research (Part B) 83:68–76, 2008. © 2008 Wiley‐Liss, Inc.
Towards an integrated understanding of the structure and mechanics of the cell nucleus
Authors: Rowat Amy C. , Lammerding Jan , Herrmann Harald , Aebi Ueli 
Published: February 2008

AbstractChanges in the shape and structural organization of the cell nucleus occur during many fundamental processes including development, differentiation and aging. In many of these processes, the cell responds to physical forces by altering gene expression within the nucleus. How the nucleus itself senses and responds to such mechanical cues is not well understood. In addition to these external forces, epigenetic modifications of chromatin structure inside the nucleus could also alter its physical properties. To achieve a better understanding, we need to elucidate the relationship between nuclear structure and material properties. Recently, new approaches have been developed to systematically investigate nuclear mechanical properties. These experiments provide important new insights into the disease mechanism of a growing class of tissue‐specific disorders termed ‘nuclear envelopathies’. Here we review our current understanding of what determines the shape and mechanical properties of the cell nucleus. BioEssays 30:226–236, 2008. © 2008 Wiley Periodicals, Inc.
Insight into initiator–DNA interactions: a lesson from the archaeal ORC
Authors: Tada Shusuke , Kundu Lena R. , Enomoto Takemi 
Published: February 2008

AbstractAlthough initiation of DNA replication is considered to be highly coordinated through multiple protein–DNA and protein–protein interactions, it is poorly understood how particular locations within the eukaryotic chromosome are selected as origins of DNA replication. Here, we discuss recent reports that present structural information on the interaction characteristics of the archaeal orthologues of the eukaryotic origin recognition complex with their cognate binding sequences.1,2 Since the archaeal replication system is postulated as a simplified version of the one in eukaryotes, by analogy, these works provide insights into the functions of the eukaryotic initiator proteins. BioEssays 30:208–211, 2008. © 2008 Wiley Periodicals, Inc.
Gene expression studies on bio‐electrosprayed primary cardiac myocytes
Authors: Barry Seán P. , Jayasinghe Suwan N. , Pericleous Charis , Hubank Mike , Latchman David S. , Stephanou Anastasis 
Published: February 2008

AbstractCardiovascular pathology accounts for the greatest number of mortalities in the western world and thus the development of ex vivo cardiac tissue has vast potential in cardiac therapy. Bio‐electrosprays (BES), a recently discovered direct cell engineering protocol, has demonstrated tremendous applicability for regenerative and therapeutic medicine. For bio‐electrospraying to be carried forward as a novel method of cardiac tissue engineering, it is important that the process does not adversely affect cellular physiology. Our previous work has shown that bio‐electrospraying does not induce cell death, activate intracellular stress pathways or induce DNA damage in primary cardiac myocytes. Here we show for the first time using genome‐wide microarray analysis, that bio‐electrospraying has no negative effects on global gene expression in cardiac myocytes. Moreover, we show that bio‐electrospraying does not lead to endothelial cell activation. These data suggest that BES has minimal effect upon the physiology of cardiac myocytes and endothelial cells and thus paves the way for the development of BES in cardiac tissue engineering.
Challenges and opportunities for training the next generation of biophysicists: Perspectives of the directors of the Molecular Biophysics Training Program at Northwestern University
Authors: Neuhaus Francis , Widom Jonathan , MacDonald Robert , Jardetzky Theodore , Radhakrishnan Ishwar 
Published: February 2008

AbstractMolecular biophysics is a broad, diverse, and dynamic field that has presented a variety of unique challenges and opportunities for training future generations of investigators. Having been or currently being intimately associated with the Molecular Biophysics Training Program at Northwestern, we present our perspectives on various issues that we have encountered over the years. We propose no cookie‐cutter solutions, as there is no consensus on what constitutes the “ideal” program. However, there is uniformity in opinion on some key issues that might be useful to those interested in establishing a biophysics training program. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 253–255, 2008.
The Interdisciplinary Biophysics Graduate Program at the University of Michigan
Authors: Gafni Ari , Walter Nils G. 
Published: February 2008

AbstractThe Michigan Biophysics Graduate Program (MBGP) was established in 1949, making it one of the first such programs in the world. The intellectual base of the program was significantly broadened in the 1980 when faculty members from a number of other units on campus were invited to join. Currently over forty faculty members from a variety of disciplines participate as mentors for the Ph.D. students enrolled in the MBGP providing our students with rich opportunities for academic learning and research. The MBGP has two main objectives: 1) to provide graduate students with both the intellectual and technical training in modern biophysics, 2) to sensitize our students to the power and unique opportunities of interdisciplinary work and thinking so as to train them to conduct research that crosses the boundaries between the biological and physical sciences. The program offers students opportunities to conduct research in a variety of areas of contemporary biophysics including structural biology, single molecule spectroscopy, spectroscopy and its applications, computational biology, membrane biophysics, neurobiophysics and enzymology. The MBGP offers a balanced curriculum that aims to provide our students with a strong academic base and, at the same time, accommodate their different academic backgrounds. Judging its past performance through the success of its former students, the MBGP has been highly successful, and there is every reason to believe that strong training in the biophysical sciences, as provided by the MBGP, will become even more valuable in the future both in the academic and the industrial settings. in the academic and the industrial settings. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 256–261, 2008.
Surgical anatomy of the external branch of the superior laryngeal nerve and its clinical significance in head and neck surgery
Authors: Kochilas Xenophon , Bibas Athanasios , Xenellis John , Anagnostopoulou Sofia 
Published: February 2008

AbstractInjury of the external branch of the superior laryngeal nerve (EBSLN) increases the morbidity following a variety of neck procedures and can have catastrophic consequences in people who use their voice professionally. Identification and preservation of the EBSLN are thus important in thyroidectomy, parathyroidectomy, carotid endarterectomy, and anterior cervical spine procedures, where the nerve is at risk. There are large variations in the anatomical course of the EBSLN, which makes the intraoperative identification of the nerve challenging. The topographic relationship of the EBSLN to the superior thyroid artery and the upper pole of the thyroid gland are considered by many authors to be the key point for identifying the nerve during surgery of the neck. The classifications by Cernea et al. ([1992a] Head Neck 14:380–383; [1992b] Am. J. Surg. 164:634–639) and by Kierner et al. ([1998] Arch. Otolaryngol. Head Neck Surg. 124:301–303), as well as clinically important connections are discussed in detail. Along with sound anatomical knowledge, neuromonitoring is helpful in identifying the EBSLN during neck procedures. The clinical signs of EBSLN injury include hoarseness, decreased voice projection, decreased pitch range, and fatigue after extensive voice use. Videostroboscopy, electromyography, voice analysis, and electroglottography can provide crucial information on the function of the EBSLN following neck surgery. Clin. Anat. 21:99–105, 2008. © 2008 Wiley‐Liss, Inc.