bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of the aggregation structure on the thermal shrinkage of polyacrylonitrile fibers during the heat‐treatment process
Authors: Wang Bin , Zhao Chun , Xiao Shijie , Zhang Jing , Xu Lianghua
Published: February 2012

Secondary thermal shrinkage or chemical shrinkage involved in the thermal shrinkage of polyacrylonitrile (PAN) fibers was not only associated with the cyclization degree but also the thermal mobility of molecular chains in the aggregation structures during crosslinking. In this study, the cyclization process was monitored with differential scanning calorimetry and IR spectroscopy. The evolution of aggregation structures throughout cyclization and variations in the secondary shrinkage for the PAN fibers were characterized with wide‐angle X‐ray diffraction and thermal mechanical analysis, respectively. The results show that with increasing temperature, the cyclization degree increased; the cyclization occurred first in amorphous regions and then extended to the crystalline regions. Correspondingly, the secondary shrinkage also increased and could be separated into two stages: those of the amorphous and crystalline phases. The shrinkage of the crystalline regions was much bigger than that of the amorphous regions. For fibers with different aggregation structures, the crystallinity affected the cyclization degree in the amorphous and crystalline regions and resulted in the difference in total shrinkage. Furthermore, because the unoriented molecular chains in both the amorphous and crystalline regions shrank more after cyclization, the shrinkage of both regions was primarily decided by the level of orientated molecular chains participating in the cyclization. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synergy of magnesium and calcium oxides in intumescent flame‐retarded polypropylene
Authors: Ma Zhi‐Ling , Fan Cong‐Ran , Lu Guang‐Yu , Liu Xiu‐Ying , Zhang Hong
Published: February 2012

An intumescent flame retardant (IFR), pentaerytheritol phosphate ester melamine salt (PPEM) was synthesized and chemically modified by magnesium oxide (MgO) or/and calcium oxide (CaO), respectively. The fire retardant efficiency of MgO and CaO as synergistic agents in polypropylene (PP) was evaluated by normal fire testing methods. The results showed that MgO and CaO exhibited a synergistic effect on fire retardancy of PP. The addition of 0.2% of MgO or CaO into PP/PPEM composite could decrease the self‐extinguishing time and improve the limited oxygen index (LOI) obviously. The cone calorimeter (CONE) tests and the thermal analysis revealed that the introduction of MgO and CaO neutralized the acidity of PPEM, which leads to a thermal stabilization and a delay of the intumescent process of the system, and promote the formation of a high quality charred layer which can prevent PP from decomposing. Thus, a suitable amount of MgO and CaO acts as a synergistic agent in the flame‐retarded PP/PPEM system. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of corn starch content in thermoplastic starch/low‐density polyethylene blends on their mechanical and flow properties
Authors: Sabetzadeh Maryam , Bagheri Rouhollah , Masoomi Mahmood
Published: February 2012

The aim of this work is to prepare low‐density polyethylene (LDPE)/thermoplastic corn starch (TPCS) compounds containing the highest amount of starch for biodegradable applications. It is intended to increase concentration of corn starch into LDPE without affecting basic required mechanical properties of LDPE plastics for disposable products. LDPE/TPCS blends containing different contents of TPCS (0–40 wt %) and a constant amount of LDPE grafted maleic anhydride [PE‐g‐MA (3 wt %)] are prepared using a single‐screw extruder. The prepared blends are evaluated for their mechanical, flow, and water absorption properties. Scanning electron micrographs of the samples show improvement in dispersion of the starch particles in LDPE matrix in the presence of PE‐g‐MA as a compatibilizer. The Young's modulus and impact strength properties reduce by increasing corn starch content in TPCS. The ultimate tensile strength and elongation at break of the samples show that the blends with 25 wt % TPCS have the required mechanical properties to produce plastic packaging products, as evidenced by ASTM D 4976‐04. The results of rheological tests indicate that as shear rate increases, the apparent viscosity of the blends decreases (shear thinning). The addition of starch to LDPE also decreases the melt flow index values of the samples. The water absorption of the samples increases with increasing starch concentrations at a constant time of water immersion. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electrosynthesis and characterization of a new multielectrochromic copolymer of 1,4‐bis(2‐thienyl) benzene with 3,4‐ethylenedioxythiophene
Authors: Cui Chuansheng , Xu Lianyi , Zhao Jinsheng , He Qingpeng , Wang Bin
Published: February 2012

A copolymer based on 1,4‐bis(2‐thienyl) benzene (BTB) and 3,4‐ethylenedioxythiophene was electrochemically synthesized in acetonitrile containing sodium perchlorate (NaClO4). Cyclic voltammetry, ultraviolet–visible spectroscopy, and Fourier transform infrared analyses confirmed that the resulting polymer was a copolymer rather than a blend or a composite of the respective homopolymers. Poly(1,4‐bis(2‐thienyl) benzene) has only two colors; it switches between yellow in the neutral state and green in the oxidized state, whereas the poly[1,4‐bis(2‐thienyl) benzene‐co‐3,4‐ethylenedioxythiophene] (PBTBE) film exhibited five different colors (brown–red, orange–yellow, yellowish green, green, and blue). This revealed distinct electrochromic properties from that of the BTB homopolymer film. The maximum optical contrast (ΔT %) and response time of the copolymer film were measured to be 27.8% and 0.51 s, respectively, at 780 nm. An electrochromic device (ECD) based on PBTBE and poly(3,4‐ethylenedioxythiophene) was also constructed and characterized. This ECD showed a ΔT % value of 22.2% in the visible region with a response time of 0.43 s at 616 nm. The coloration efficiency of the device was calculated to be 129 cm2/C at 616 nm. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Solid‐phase extraction of S‐(‐)‐amlodipine from plasma with a uniformly sized molecularly imprinted polymer
Authors: Luo Kaixia , Liu Meng , Fu Qiang , Amut Elijan , Zeng Aiguo , Chang Chun
Published: February 2012

To specifically extract S‐(‐)‐amlodipine from plasma, uniformly sized molecularly imprinted polymers (MIPs) for S‐(‐)‐amlodipine were prepared in an aqueous system by multistep swelling and polymerization with methacrylic acid as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, and toluene as a porogen. Scanning electron microscopy was used to identify the structural features of the obtained polymers. 1H‐NMR and high‐performance liquid chromatographic analysis were performed to explore the possible recognition mechanism. The results reveal that spherical polymer beads with uniform size and good monodispersity were obtained, and the MIPs showed specific recognition ability for the template molecule. The ionic hydrophobic and hydrogen‐bonding interactions were inferred to play an important role in the recognition mechanism. The results indicate that the MIPs could be used as a solid‐phase extraction sorbent for the concentration and purification of S‐(‐)‐amlodipine from plasma with a high efficiency. The linear range was 0.25–8.00 μg/mL with a correlation coefficient of 0.9948. The average recovery was 98.3% with relative standard deviation (RSD) less than 9.1%. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Enzyme‐catalyzed ring‐opening polymerization of cyclic esters in the presence of poly(ethylene glycol)
Authors: Sobczak Marcin
Published: February 2012

Low‐molecular‐weight polyesters were obtained by the ring‐opening homopolymerization and copolymerization reaction of ϵ‐caprolactone, rac‐ or L‐lactide, and glycolide in the presence of poly(ethylene glycol) with an enzyme catalyst, a lipase from Candida antarctica, Pseudomonas cepacia, or Pseudomonas fluorescens. The influence of several parameters, including time, temperature, and enzyme and monomer concentration, on the polymerization rate was studied. The resulting polymers were characterized by 1H‐NMR or 13C‐NMR, Fourier transform infrared spectroscopy, matrix‐assisted laser desorption/ionization–time of flight mass spectroscopy, and gel permeation chromatography. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Nanostructured membranes based on cellulose acetate obtained by electrospinning, part 1: Study of the best solvents and conditions by design of experiments
Authors: Nista Silvia V. Guerra , Peres Leila , D'Ávila Marcos A. , Schmidt Flávio L. , Innocentini Mei Lucia H.
Published: February 2012

The electrospinning of cellulose acetate (CA) was investigated to develop biodegradable nanostructured membranes for the controlled release of drugs used to treat skin wounds. CA nanofibers were successfully prepared via the electrospinning in the four mixed solvents acetic acid : water; acetone : water; DMAc : acetone; DMAc : acetone : water. Design of experiments (DOE) was applied to see what combinations of parameters could affect the production of electrospun microfibers and nanofibers to optimize the process. The results of this work indicated that both the processing parameters and the solvent mixtures were responsible for the fiber diameter and nanostructure membrane appearance. The optimized condition for each solvent mixture was obtained and compared with each one of the others. The best conditions achieved were dimethylacetamida (DMAc) : acetone with 17% of CA, which provided homogeneous and free bead fibers with an average diameter of 295 nm. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effects of kinetics coefficients on ternary phase separation during the wet spinning process
Authors: Han Yu , Wang Jun , Zhang Hongdong
Published: February 2012

A new Monte Carlo diffusion model is employed to simulate the phase separation of the ternary system during wet spinning process. Our results illustrate the thermodynamics parameters are the primary factors in morphology determination during the phase separation process. Meanwhile by varying kinetic parameters different fiber structures ranging from dust‐like, finger‐like to sponge‐like morphologies are obtained. The morphological patterns are discussed in relation to the rate of particle exchange and the phase diagram. On the basis of the systematical simulation experiments we propose how the competition between segment–solvent and solvent–nonsolvent exchange determines the ultimate fiber morphologies in spinning solution.© 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Study on the mechanism of the formation of polyhedral oligomeric silsesquioxanes by the 2D correlation infrared spectral
Authors: Qu Yanbin , Huang Guangsu , Wang Xiaoan , Li Jiali
Published: February 2012

Synthesis of polyhedral oligomeric silsesquioxanes (POSS) by the hydrolytic condensation reaction of trifunctional organosilanes [e.g., RSiCl3 or RSi(OR)3] may have achieved success. However, the exact formation mechanism of POSS, especially, an evolution process in the reaction still remains unclear. In this work, a real‐time FTIR was carried out to trace the synthesis process of POSS. It was found that linear siloxanes, cyclic siloxanes, and cage‐like polysiloxanes were formed during the reaction. With the help of generalized two‐dimensional (2D) correlation analysis, we obtained exact sequential change among the three siolxanes, with the linear silicons formed initially. Following this was the emergence of cyclic siloxanes, and finally the cage‐like polysiloxanes. Consequently, we not only proved the existence of the linear and cyclic siloxanes but also accurately detected the sequential change of the siloxanes in the process, which exhibited an intact and visual evolution process of POSS formation. Based on this, the reaction mechanism is presented. Finally, the chemical structure of cage‐like products was further characterized by 29Si‐NMR and GPC measurements. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Developing chromic dyeable PET nanocomposites: The dye absorption and complex formation mechanisms
Authors: Dastjerdi Roya , Mojtahedi M. R. M. , Heidari N.
Published: February 2012

This research aimed to investigate the possibility of enhancement of polyethylene terephthalate (PET) dyeability using nanotechnology. Different kinds of disperse, acidic, and chromic dyes were used for dyeing of produced PET/silver nanocomposite fine multifilament yarns produced at the take up speeds of 3000 m min−1 and their prepared fabrics. Dyeability improved by using acidic dyes. However, the more promotion effect was achieved by chromic dyes. No effect on absorption of disperse dyes revealed that no physical effect can be considered for dye absorption. The electrostatic interaction between silver and acidic dye molecules and forming the coordinative bonds with chromic dye molecules on nanocomposite yarns and fabrics were concluded and thoroughly discussed. Applying chromic dye with the more potential of creating coordinative bonds intensified the improvement of dyeability. Optimized silver ratio for the dyeability enhancement was affected by the mechanisms of dye absorptions discussed and proven by investigating dye concentrations in the effluent baths after the dyeing processes. It has been found that the steric hindrance is the key factor for absorption of chromic dyes; however, it is different in the case of acidic dyes, well discussed according to the dye absorptions mechanisms. The results can be also considered as evidence to prove forming the coordinative bonds with chromic dye molecules. This has also been confirmed by appearing a bathochromic shift in the absorption peaks by increasing dyeability using chromic dye. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
The influence of low‐ and high‐linear energy transfers on some physical properties of poly(methyl‐methacrylate) samples
Authors: Eissa Mostafa F. , Kaid Maysa A. , Kamel Nasser A.
Published: February 2012

Clear poly(methyl‐methacrylate)—PMMA—dosimeter is widely used in food irradiations. Positron annihilation lifetime spectroscopy (PALS) is one of the unique tools used for studying free‐volumes and open‐volume type defects in solid media. The Vicker's microhardness measurements offer a simple and nondestructive tool for investigating the mechanical behavior of polymer materials. PALS as well as microhardness measurements were carried out for PMMA samples, irradiated with low‐ and high‐linear energy transfers (LET). The low‐LET irradiations were provided at lethal doses of gamma radiations for vegetative bacteria. Such irradiations showed a chain scission in the PMMA samples. High‐LET irradiations showed behavior different from the low‐LET ones. The observed behavior depends on the alpha particle fluence. The microhardness testing was carried out for virgin and irradiated PMMA samples at high‐LET. A negative correlation was found between PALS measurements and microhardness results. The optical characteristics and structural studies for the virgin and irradiated PMMA samples were in agreement with the PALS and microhardness measurements. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Electrocatalytic performance of Pt supported on polyaniline‐poly(styrene sulfonate) hydrogel
Authors: Jia Yujie , Jiang Jianchun , Sun Kang , Dai Tingyang
Published: February 2012

A new type of polyaniline‐poly (styrene sulfonate) (PAn‐PSS) hydrogel was fabricated with high concentrations of aniline (An) and PSS via supramolecular self‐assembly. Then 30 segments of cyclic voltammograms from −0.2 to 0.8 V were conducted to deposit the Pt particles on the surface of the hydrogel. For comparison, PAn‐PSS colloid was synthesized with the ordinary method. The morphology and composition of the PAn‐PSS hydrogel–Pt and PAn‐PSS colloid–Pt were investigated by the TEM and EDX measurements. Furthermore, the shift of the feature bands in FTIR and UV–vis spectra confirms that the PAn‐PSS hydrogel has interactions with Pt. So the Pt particles are dispersed and the electrons are shuttled more freely, which is beneficial for the electrochemical performance. The cyclic voltammograms and chronoamperometric measurements show that Pt supported on the PAn‐PSS hydrogel has preferable electrocatalytic performance toward the oxidation of methanol than the one on PAn‐PSS colloid. Hence, PAn‐PSS hydrogel–Pt can be a promising catalyst for methanol in fuel cells. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Hydroxyalkyl derivatives of phenyldiamine as modifiers for unsaturated polyester resins. II. derivatives of phenyl‐1,3‐diamine
Authors: Duliban Jerzy
Published: February 2012

The results are presented on the synthesis of new modifiers and on functioning of these modifiers in unsaturated polyester (UP) resins. The modifiers were obtained by reacting ethylene oxide or propylene oxide with phenyl‐1,3‐diamine. The effect of the modifiers and cobalt accelerator on the reactivity of resins was studied. When used in the amount of up to 1.50 wt %, the amines substantially (several times) reduced the gelation time of modified UPs. The reactivity of resins, however, improved in expense of their stability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Progressive Anatomical Closure of Foramen Ovale in Normal Neonatal Mouse Hearts
Authors: Cole‐Jeffrey Colleen T. , Terada Ryota , Neth Matthew R. , Wessels Andy , Kasahara Hideko
Published: February 2012

In the prenatal heart, right‐to‐left atrial shunting of blood through the foramen ovale is essential for proper circulation. After birth, as the pulmonary circulation is established, the foramen ovale functionally closes as a result of changes in the relative pressure of the two atrial chambers, ensuring the separation of oxygen depleted venous blood in the right atrium from the oxygenated blood entering the left atrium. Little is known regarding the process of anatomical closure of the foramen ovale in the postnatal heart. Genetically engineered mouse models are powerful tools to study heart development and to reveal mechanisms underlying cardiac anomalies, including defects in atrioventricular septation. Using three‐dimensional reconstructions of serial sectioned hearts at early postnatal Days 2–7, we show a progressive reduction in the size of the interatrial communication throughout this period and complete closure by postnatal Day 7. Furthermore we demonstrate that fusion of the septum primum and septum secundum occurs between 4 weeks and 3 months of age. This study provides a standard timeline for morphological closure of the right–left atrial communication and fusion between the atrial septa in normal mouse hearts. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.
Genome‐wide association analysis of juvenile idiopathic arthritis identifies a new susceptibility locus at chromosomal region 3q13
Authors: Thompson Susan D. , Marion Miranda C. , Sudman Marc , Ryan Mary , Tsoras Monica , Howard Timothy D. , Barnes Michael G. , Ramos Paula S. , Thomson Wendy , Hinks Anne , Haas Johannes‐Peter , Prahalad Sampath , Bohnsack John F. , Wise Carol A. , Punaro Marilynn , Rosé Carlos D. , Pajewski Nicholas M. , Spigarelli Michael , Keddache Mehdi , Wagner Michael , Langefeld Carl D. , Glass David N.
Published: February 2012

Objective

In a genome‐wide association study of Caucasian patients with juvenile idiopathic arthritis (JIA), we have previously described findings limited to autoimmunity loci shared by JIA and other diseases. The present study was undertaken to identify novel JIA‐predisposing loci using genome‐wide approaches.

Methods

The discovery cohort consisted of Caucasian JIA cases (n = 814) and local controls (n = 658) genotyped on the Affymetrix Genome‐Wide SNP 6.0 Array, along with 2,400 out‐of‐study controls. In a replication study, we genotyped 10 single‐nucleotide polymorphisms (SNPs) in 1,744 cases and 7,010 controls from the US and Europe.

Results

Analysis within the discovery cohort provided evidence of associations at 3q13 within C3orf1 and near CD80 (rs4688011) (odds ratio [OR] 1.37, P = 1.88 × 10−6) and at 10q21 near JMJD1C (rs647989 [OR 1.59, P = 6.1 × 10−8], rs12411988 [OR 1.57, P = 1.16 × 10−7], and rs10995450 [OR 1.31, P = 6.74 × 10−5]). Meta‐analysis provided further evidence of association for these 4 SNPs (P = 3.6 × 10−7 for rs4688011, P = 4.33 × 10−5 for rs6479891, P = 2.71 × 10−5 for rs12411988, and P = 5.39 × 10−5 for rs10995450). Gene expression data on 68 JIA cases and 23 local controls showed cis expression quantitative trait locus associations for C3orf1 SNP rs4688011 (P = 0.024 or P = 0.034, depending on the probe set) and JMJD1C SNPs rs6479891 and rs12411988 (P = 0.01 or P = 0.04, depending on the probe set and P = 0.008, respectively). Using a variance component liability model, it was estimated that common SNP variation accounts for approximately one‐third of JIA susceptibility.

Conclusion

Genetic association results and correlated gene expression findings provide evidence of JIA association at 3q13 and suggest novel genes as plausible candidates in disease pathology.
Brief Report: Induction of sustained remission in recurrent catastrophic antiphospholipid syndrome via inhibition of terminal complement with eculizumab
Authors: Shapira Iuliana , Andrade Danieli , Allen Steven L. , Salmon Jane E.
Published: February 2012

Objective

Catastrophic antiphospholipid syndrome (CAPS) is characterized by histopathologic evidence of small vessel thrombosis, dysfunction of multiple organs occurring over a short period of time, and laboratory confirmation of the presence of antiphospholipid antibodies (aPL). Treatment of CAPS focuses on anticoagulation therapy and on removal of aPL that promote thrombosis by activating endothelial cells, monocytes, and platelets. Studies in animal models support the hypothesis that a more targeted intervention, such as complement inhibition, may be an effective means to prevent aPL‐induced thrombosis. Herein we describe use of an inhibitor of complement activation to treat CAPS that was refractory to conventional therapy.

Methods

Our patient was a young man who had recurrent CAPS characterized by multiple arterial thromboses in large and small vessels despite maximal anticoagulation, immunosuppression, and plasma exchange therapy. We treated him with eculizumab, an anti‐C5 monoclonal antibody that blocks activation of terminal complement.

Results

Administration of eculizumab, at doses that blocked complement activity, aborted acute progressive thrombotic events, reversed thrombocytopenia, and was associated with no further clinical episodes of thrombosis during >3 years of therapy.

Conclusion

This first report of the use and clinical efficacy of eculizumab, an inhibitor of complement activation, in the treatment of CAPS demonstrates both the importance of complement (specifically, terminal complement components) in the pathogenesis of CAPS and the therapeutic benefit of complement inactivation.
A new screening method for flunitrazepam in vodka and tequila by fluorescence spectroscopy
Authors: Leesakul Nararak , Pongampai Sirintip , Kanatharana Proespichaya , Sudkeaw Pravit , Tantirungrotechai Yuthana , Buranachai Chittanon
Published: February 2012

A new screening method for flunitrazepam in colourless alcoholic beverages based on a spectroscopic technique is proposed. Absorption and steady‐state fluorescence of flunitrazepam and its protonated form with various acids were investigated. The redshift of the wavelength of maximum absorption was distinctively observed in protonated flunitrazepam. An emissive fluorescence at 472 nm was detected in colourless spirits (vodka and tequila) at room temperature. 2‐M perchloric acid was the most appropriated proton source. By using electron ionization mass spectrometry and time‐dependent density functional theory calculations, the possible structure of protonated flunitrazepam was identified to be 2‐nitro‐N‐methylacridone, an acridone derivative as opposed to 2‐methylamino‐5‐nitro‐2′‐fluorobenzophenone, a benzophenone derivative. Copyright © 2012 John Wiley & Sons, Ltd.
DFTr Studies of Five‐ and Six‐Residue Cyclic‐β(1→4) Cellulosic Molecules
Authors: Momany Frank A. , Schnupf Udo
Published: February 2012

Density functional (DFT) conformational in vacuo studies of cellobiose have shown that ϕH‐anti conformations are low in energy relative to the syn forms, while the ψH‐anti forms are higher in energy. Further, as the cellulosic fragments became larger than a disaccharide and new hydrogen bonding interactions between multiple residues become available, stable low energy ϕH‐anti, and ψH‐anti cellulosic structures became possible. To test the stability of cyclic anti‐conformations, a number of β‐linked five‐ and six‐residue molecules were created and then energy optimized in solvent (water, n‐heptane) using the implicit solvation method COSMO at the B3LYP level of theory. The created symmetric cyclic structures were without distortion. Upon optimization some cyclic conformations were found to be of low energy when compared with linear five‐ and six‐residue chains, after correcting the energy for the exclusion of a water molecule upon cyclization. It was also obvious from the hydrogen bonding network formed above and below the plane of the cyclic structure that these structures could exhibit strong synergistic tendencies. The conformational energy preferences for clockwise “c” and counter‐clockwise “r” hydroxyl groups and preference for the hydroxymethyl rotamers is described. Because these structures contain energetically unfavorable flipped conformations in water, that is, dihedral angles of ∼180°/0° or ∼0°/180° in ϕH/ψH, it is clear that the synthesis of these compounds will be challenging. © 2012 Wiley Periodicals, Inc. Biopolymers 97:568–576, 2012.
Effects of phosphorous, nitrogen, and carbon limitation on biomass composition in batch and continuous flow cultures of the heterotrophic dinoflagellate Crypthecodinium cohnii
Authors: Pleissner Daniel , Eriksen Niels T.
Published: February 2012

We have used phosphate, nitrogen, or carbon limited batch and continuous flow cultures to study how growth and biochemical composition of the dinoflagellate Crypthecodinium cohnii CCMP 316 is affected by nutrient limitation. Specific contents of phosphorous, proteins, and starch were differently affected by nutrient limitation. The specific phosphorous content in C. cohnii varied 10–20 times depending on phosphate availability in the medium. When phosphate was available it was taken up in excess and stored to be re‐utilized during phosphate limitation. The specific protein content varied twofold. At most conditions, proteins made up 12–15% of the biomass dry weight but when cells were nitrogen limited, the specific protein content was only half this value. Floridean starch was the major cell constituent of C. cohnii accounting for 40–50% of the biomass dry weight. Only during carbon limitation did the specific starch content decrease. In contrast was the specific lipid content almost unaffected by nutrient availability and lipids accounted for 12–15% of the biomass dry weight irrespectively of which nutrient that was limiting. Lipid production does therefore not depend on nutrient limitation in C. cohnii and lipids are produced even by carbon limited cells. Cultures grown under phosphate limitation resulted in formation of cells with maximal specific contents of all the three major cell constituents; starch, lipid, and protein. Biotechnol. Bioeng. 2012; 109:2005–2016. © 2012 Wiley Periodicals, Inc.
Leukocyte counting from a small amount of whole blood using a size‐controlled microcavity array
Authors: Hosokawa Masahito , Asami Marie , Nakamura Seita , Yoshino Tomoko , Tsujimura Noriyuki , Takahashi Masayuki , Nakasono Satoshi , Tanaka Tsuyoshi , Matsunaga Tadashi
Published: February 2012

Absolute counting of total leukocytes or specific subsets within small amounts of whole blood is difficult due to a lack of techniques that enable separation of all leukocytes from limited amounts of whole blood. In this study, a microfluidic device equipped with a size‐controlled microcavity array for highly efficient separation of leukocytes from submicroliters of whole blood was developed. The microcavity array can separate leukocytes from whole blood based on differences in the size and deformability between leukocytes and other blood cells. Leukocytes recovered on aligned microcavities were continuously processed for image‐based immunophenotypic analysis. Our device successfully recovered over 90% of leukocytes in 1 µL of whole blood without pretreatment such as density gradient centrifugation or erythrocyte lysis. In addition, the proposed system successfully performed absolute enumeration of human CD4+ and CD8+ leukocytes from 1 µL of whole blood, and the obtained data showed good correlation with conventional flow cytometric analysis. Our microfluidic device has great potential as a tool for a point‐of‐care leukocyte analysis system. Biotechnol. Bioeng. 2012; 109:2017–2024. © 2012 Wiley Periodicals, Inc.
Differential effects of nitrogen and sulfur deprivation on growth and biodiesel feedstock production of Chlamydomonas reinhardtii
Authors: Cakmak Turgay , Angun Pinar , Demiray Yunus Emre , Ozkan Alper Devrim , Elibol Zeynep , Tekinay Turgay
Published: February 2012

Biodiesel production from microalgae is a promising approach for energy production; however, high cost of its process limits the use of microalgal biodiesel. Increasing the levels of triacylglycerol (TAG) levels, which is used as a biodiesel feedstock, in microalgae has been achieved mainly by nitrogen starvation. In this study, we compared effects of sulfur (S) and nitrogen (N) starvation on TAG accumulation and related parameters in wild‐type Chlamydomonas reinhardtii CC‐124 mt(−) and CC‐125 mt(+) strains. Cell division was interrupted, protein and chlorophyll levels rapidly declined while cell volume, total neutral lipid, carotenoid, and carbohydrate content increased in response to nutrient starvation. Cytosolic lipid droplets in microalgae under nutrient starvation were monitored by three‐dimensional confocal laser imaging of live cells. Infrared spectroscopy results showed that relative TAG, oligosaccharide and polysaccharide levels increased rapidly in response to nutrient starvation, especially S starvation. Both strains exhibited similar levels of regulation responses under mineral deficiency, however, the degree of their responses were significantly different, which emphasizes the importance of mating type on the physiological response of algae. Neutral lipid, TAG, and carbohydrate levels reached their peak values following 4 days of N or S starvation. Therefore, 4 days of N or S starvation provides an excellent way of increasing TAG content. Although increase in these parameters was followed by a subsequent decline in N‐starved strains after 4 days, this decline was not observed in S‐starved ones, which shows that S starvation is a better way of increasing TAG production of C. reinhardtii than N starvation. Biotechnol. Bioeng. 2012; 109:1947–1957. © 2012 Wiley Periodicals, Inc.
Utilization and evaluation of CHO‐specific sequence databases for mass spectrometry based proteomics
Authors: Meleady Paula , Hoffrogge Raimund , Henry Michael , Rupp Oliver , Bort Juan Hernandez , Clarke Colin , Brinkrolf Karina , Kelly Shane , Müller Benjamin , Doolan Padraig , Hackl Matthias , Beckmann Tim Frederik , Noll Thomas , Grillari Johannes , Barron Niall , Pühler Alf , Clynes Martin , Borth Nicole
Published: February 2012

Recently released sequence information on Chinese hamster ovary (CHO) cells promises to not only facilitate our understanding of these industrially important cell factories through direct analysis of the sequence, but also to enhance existing methodologies and allow new tools to be developed. In this article we demonstrate the utilization of CHO specific sequence information to improve mass spectrometry (MS) based proteomic identification. The use of various CHO specific databases enabled the identification of 282 additional proteins, thus increasing the total number of identified proteins by 40–50%, depending on the sample source and methods used. In addition, a considerable portion of those proteins that were identified previously based on inter‐species sequence homology were now identified by a larger number of peptides matched, thus increasing the confidence of identification. The new sequence information offers improved interpretation of proteomic analyses and will, in the years to come, prove vital to unraveling the CHO proteome. Biotechnol. Bioeng. 2012; 109:1386–1394. © 2012 Wiley Periodicals, Inc.
Quantification of fexofenadine in biological matrices: a review of bioanalytical methods
Authors: Yao Ming , Srinivas Nuggehally R.
Published: February 2012

Fexofenadine (FEX) has been extensively used for therapeutic benefits after the market withdrawal of terfenadine. Recently, the popularity of FEX has emerged owing to its unique disposition via drug transporters and, hence, it has been used as a model probe for both in vitro and in vivo investigations to understand mechanistic aspects of drug–drug interactions (DDI). Going hand in hand with the increased use of FEX in therapy and research, numerous bioanalytical methods for FEX have been published. The various published bioanalytical methods for FEX are collated in this review to provide a comprehensive information on extraction methodology, assay conditions, chromatography and detection systems. Generally, the published methods have been adequately validated and can be readily used to support the use of FEX in pharmcokinetic, DDI and mechanistic investigations. Copyright © 2012 John Wiley & Sons, Ltd.
PD and fuzzy logic control for earthquake resilient structures
Authors: Alvarez Pedro , McElwain Brittany , Thesing Laura , Edalath Sanooj , Kukreti Anant , Cohen Kelly
Published: February 2012

This research was conducted within the framework of a National Science Foundation sponsored summer Research Experience for Undergraduate (REU) students. This research considers small‐scale and mathematical models of simple one‐story structures that are subjected to free and base‐motion excitations and installed with and without passive damping devices to gain an understanding of their dynamic behavior while reviewing active and semi‐active damping means being applied and researched today. Using computer programming and numerical methods, the goal is to understand and counteract catastrophic disasters to structures caused by earthquakes. The research is broken down into a number of MATLAB simulations and experiments in order to understand basic dynamic and control features required to design earthquake resilient buildings. These experiments include free vibration experiments to test for the stiffness of columns for different heights and to test for the natural frequency and damping ratio of a one‐story structure under different mass loads. Active PD control was then applied to an experimental system experiencing accelerations attributed to the Northridge 1994, Kobe 1995, El Centro 1940, and Mendocino 1992 earthquakes. Robustness comparisons were made between (1) P control; (2) D control; and (3) PD control for the above earthquake inputs to the shaker. A fuzzy logic controller was developed to effectively control transient vibrations. The uniqueness of this control concept is that the fuzzy control continuously varies the damping characteristics of a semi‐active tuned mass damper (TMD). It was concluded that a fuzzy logic based TMD was more effective than a regular passive TMD, by providing half the settling times. © 2012 Wiley Periodicals, Inc. Comput Appl Eng Educ 22: 142–152, 2014
Wiki learning system patterns for academic courses
Authors: Nejkovic Valentina , Tosic Milorad
Published: February 2012

Academic courses have started to feature an expanding variety of innovative ways in using different technologies in order to improve effectiveness of teaching and learning process. Among these technologies Wikis are getting important role among teachers, academics, and educators in general as teaching as well as collaboration tool. This article presents overview and systematization of Wiki Learning System in a form of educational Wiki patterns with a goal to support easier and more coherent integration of collaboration and interaction in teaching and learning activities. Results of several consecutive years of using Wiki Learning System and Wiki‐based methodological teaching approaches based on Wiki patterns are presented regarding final exams' outcomes of university students. The outcomes' evaluation is based on data collected from faculty archive as well as using survey–questionnaire‐based method.© 2012 Wiley Periodicals, Inc. Comput Appl Eng Educ 22:678–685, 2014; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21559
Towards a quantitative approach for comparing crowds
Authors: Musse Soraia R. , Cassol Vinicius J. , Jung Cláudio R.
Published: February 2012

In this paper, we propose a new model to quantitatively compare global flow characteristics of two crowds. The proposed approach explores a 4‐D histogram that contains information on the local velocity (speed and orientation) of each spatial position, and the comparison is made using histogram distances. The 4‐D histogram also allows the comparison of specific characteristics, such as distribution of orientations only, speed only, relative spatial occupancy only, and combinations of such features. Experimental results indicate that the proposed quantitative metric correlates with visual inspection. Copyright © 2012 John Wiley & Sons, Ltd.
A review of models of fluctuating protrusion and retraction patterns at the leading edge of motile cells
Authors: Ryan Gillian L. , Watanabe Naoki , Vavylonis Dimitrios
Published: February 2012

A characteristic feature of motile cells as they undergo a change in motile behavior is the development of fluctuating exploratory motions of the leading edge, driven by actin polymerization. We review quantitative models of these protrusion and retraction phenomena. Theoretical studies have been motivated by advances in experimental and computational methods that allow controlled perturbations, single molecule imaging, and analysis of spatiotemporal correlations in microscopic images. To explain oscillations and waves of the leading edge, most theoretical models propose nonlinear interactions and feedback mechanisms among different components of the actin cytoskeleton system. These mechanisms include curvature‐sensing membrane proteins, myosin contraction, and autocatalytic biochemical reaction kinetics. We discuss how the combination of experimental studies with modeling promises to quantify the relative importance of these biochemical and biophysical processes at the leading edge and to evaluate their generality across cell types and extracellular environments. © 2012 Wiley Periodicals, Inc.
Correlation of drug‐induced apoptosis assay results with oncologist treatment decisions and patient response and survival
Authors: Bosserman Linda D. , Rajurkar Swapnil P. , Rogers Karl , Davidson Dirk C. , Chernick Michael , Hallquist Allan , Malouf Debbee , Presant Cary A.
Published: February 2012

BACKGROUND:

An observational prospective nonblinded clinical trial was performed to determine the effect of a drug‐induced apoptosis assay results on treatments planned by oncologists.

METHODS:

Purified cancer cells from patient biopsies were placed into the MiCK (Microculture Kinetic) assay, a short‐term culture, which determined the effects of single drugs or combinations of drugs on tumor cell apoptosis. An oncologist received the assay results before finalizing the treatment plan. Use of the MiCK assay was evaluated and correlated with patient outcomes.

RESULTS:

Forty‐four patients with successful MiCK assays from breast cancer (n = 16), nonsmall cell lung cancer (n = 6), non‐Hodgkin lymphoma (n = 4), and others were evaluated. Four patients received adjuvant chemotherapy after MiCK, and 40 received palliative chemotherapy with a median line of therapy of 2. Oncologists used the MiCK assay to determine chemotherapy (users) in 28 (64%) and did not (nonusers) in 16 patients (36%). In users receiving palliative chemotherapy, complete plus partial response rate was 44%, compared with 6.7% in nonusers (P < .02). The median overall survival was 10.1 months in users versus 4.1 months in nonusers (P = .02). Relapse‐free interval was 8.6 months in users versus 4.0 months in nonusers (P < .01).

CONCLUSIONS:

MiCK assay results are frequently used by oncologists. Outcomes appear to be statistically superior when oncologists use chemotherapy based on MiCK assay results compared with when they do not use the assay results. When available to oncologists, MiCK assay results help to determine patient treatment plans. Cancer 2012. © 2012 American Cancer Society.
Application layer forward error correction for multicast streaming over LTE networks
Authors: Bouras Christos , Kanakis Nikolaos , Kokkinos Vasileios , Papazois Andreas
Published: February 2012

The next step beyond third generation mobile networks is the Third Generation Partnership Project standard, named Long Term Evolution. A key feature of Long Term Evolution is the enhancement of multimedia broadcast and multicast services (MBMS), where the same content is transmitted to multiple users located in a specific service area. To support efficient download and streaming delivery, the Third Generation Partnership Project included an application layer forward error correction (AL‐FEC) technique based on the systematic fountain Raptor code, in the MBMS standard. To achieve protection against packet losses, Raptor codes introduce redundant packets to the transmission, that is, the forward error correction overhead. In this work, we investigate the application of AL‐FEC over MBMS streaming services. We consider the benefits of AL‐FEC for a continuous multimedia stream transmission to multiple users and we examine how the amount of forward error correction redundancy can be adjusted under different packet loss conditions. For this purpose, we present a variety of realistic simulation scenarios for the application of AL‐FEC and furthermore we provide an in‐depth analysis of Raptor codes performance introducing valuable suggestions to achieve efficient use of Raptor codes. Copyright © 2012 John Wiley & Sons, Ltd.
Cytomorphologic diagnosis and HPV testing of metastatic and primary oropharyngeal squamous cell carcinomas: A review and summary of the literature
Authors: Jarboe Elke A. , Hunt Jason P. , Layfield Lester J.
Published: February 2012

A significant proportion of squamous cell carcinomas (SCC) of the oropharynx are associated with high‐risk human papillomavirus (HPV). These HPV‐related carcinomas are prognostically and therapeutically different from traditional SCC of the head and neck. Cervical metastases from head and neck primary SCC are frequently investigated by fine‐needle aspiration (FNA). HPV testing of cytologic samples from these lesions would potentially simplify diagnosis and therapeutic planning. This review summarizes current methodologies for HPV testing of FNA specimens and the role of HPV typing in diagnosis, prediction of prognosis, and selection of therapy. Diagn. Cytopathol. 2012;40:491–497. © 2012 Wiley Periodicals, Inc.
Diagnosis of gastrointestinal stromal tumors from minute specimens: Cytomorphology, immunohistochemistry, and molecular diagnostic findings
Authors: Layfield Lester J. , Wallander Michelle L.
Published: February 2012

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal neoplasm arising from the gastrointestinal tract. Workup of these lesions includes morphologic study and immunohistochemical and often molecular diagnostic analysis. Historically, these neoplasms had been included under a number of diagnostic categories including leiomyoma, leiomyosarcoma, schwannoma, and leiomyoblastoma. The lesions that were clearly sarcomatous were difficult to treat and therapeutically refractory to chemotherapeutic agents. Significant progress in our understanding of these neoplasms and our ability to successfully treat them occurred following the discovery that they were immunoreactive for KIT protein and harbored activating mutations in the KIT gene. Many are initially diagnosed by fine‐needle aspiration (FNA) but workup may include mutational analysis to help direct therapy. This review outlines a practical approach to the cytologic diagnosis of GISTs and their molecular workup on small specimens obtained by FNA or core biopsy. Diagn. Cytopathol. 2012;40:484–490. © 2012 Wiley Periodicals, Inc.
Modification of hippocampal circuitry by adult neurogenesis
Authors: Song Juan , M. Christian Kimberly , Ming Guo‐li , Song Hongjun
Published: February 2012

The adult hippocampus is one of the primary neural structures involved in memory formation. In addition to synapse‐specific modifications thought to encode information at the subcellular level, changes in the intrahippocampal neuro‐populational activity and dynamics at the circuit‐level may contribute substantively to the functional capacity of this region. Within the hippocampus, the dentate gyrus has the potential to make a preferential contribution to neural circuit modification owing to the continuous addition of new granule cell population. The integration of newborn neurons into pre‐existing circuitry is hypothesized to deliver a unique processing capacity, as opposed to merely replacing dying granule cells. Recent studies have begun to assess the impact of hippocampal neurogenesis by examining the extent to which adult‐born neurons participate in hippocampal networks, including when newborn neurons become engaged in ongoing network activity and how they modulate circuit dynamics via their unique intrinsic physiological properties. Understanding the contributions of adult neurogenesis to hippocampal function will provide new insight into the fundamental aspects of brain plasticity, which can be used to guide therapeutic interventions to replaceneural populations damaged by disease or injury. © 2012 Wiley Periodicals, Inc. Develop Neurobiol 72: 1032–1043, 2012
Dorsal–ventral patterning of the neural tube: A tale of three signals
Authors: Le Dréau Gwenvael , Martí Elisa
Published: February 2012

Development of the vertebrate nervous system begins with the acquisition of neural identity from the midline dorsal‐ectodermal cells of the gastrulating embryos. The subsequent progressive specification of the neural plate along its anterior–posterior and dorsal–ventral (DV) axes allows the generation of the tremendous variety of neuronal and glial cells that compose the vertebrate central nervous system (CNS). Studies on the development of the spinal cord, the anatomically simplest part of the CNS, have generated most of our current knowledge on the signaling events and the genetic networks that orchestrate the DV patterning of the neural plate. In this review, we discuss the recent advances in our understanding of these events and highlight unresolved questions. We focused our attention on the activity and the integration of the three main instructive cues: Sonic hedgehog, the Wnts and the Bone Morphogenetic Proteins, giving particular attention to the less well understood dorsal signaling events. © 2012 Wiley Periodicals, Inc. Develop Neurobiol, 2012