bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review of Developments in Electrospinning Technology: New Opportunities for the Design of Artificial Tissue Structures
Authors: Szentivanyi Andreas L. , Zernetsch Holger , Menzel Henning , Glasmacher Birgit
Published: December 2011

Purpose

As a technology for the production of micro- and nano structured scaffold materials, electro-spinning has gained widespread acceptance in the medical research community over the last decade. The process generates a non-woven fiber mat consisting of one continuous filament with diameters ranging from the micron to the nanometer range. Because of its similarity to the filamentous microenvironment in native tissues, it is most often used as scaffold material in tissue engineering applications. This similarity promotes a more positive cell response to the generated fibers than to bulk material alone. However, because current electrospinning equipment does not yet fully utilize the potential of the process technology, the reproducibility of the scaffold structure is often limited. It is thus the goal of this review to describe the current state of electrospinning process technology with respect to the design of artificial tissue structures.

Method

This review is based on a comprehensive examination conducted in 2007 and 2008 of patents filed with the European Patent Organization and other scientific publications.

Results

It describes selected technical developments in electrospinning related to the production of non-woven fiber scaffolds and their implications in the design of artificial tissue structures. Specifically, it describes techniques for the production of aligned fiber structures, multilayered, multiscaled and multifiber scaffolds, fiber modification and functionalization, and useful advances in process control. It also presents technical sketches showing in detail how to implement the techniques presented into electrospinning equipment setups. Finally, it discusses remaining limitations that pertain to the design of scaffold materials.
An Overview on the Photocatalytic Activity of Nano-Doped-TiO2 in the Degradation of Organic Pollutants
Authors: Tan Yong Nian , Wong Chung Leng , Mohamed Abdul Rahman
Published: December 2011

This paper aims to review and summarize the recent works on the photocatalytic degradation of various organic pollutants in the presence of nano-doped-TiO2 photocatalysts. In this regard, three main aspects are examined: (a) the presence of various dopants (metal dopants, nonmetal dopants, halogen dopants, metalloid dopants, and codopants) in the formation of nano-doped-TiO2 photocatalysts, (b) the effect of the presence of dopants on the photocatalytic degradation of organic pollutants, and (c) the effects of various operating parameters on the photocatalytic degradation of organic pollutants in the presence of nano-doped-TiO2 photocatalysts. Reports resulted suggest that the formation of a high percentage of the anatase phase, small crystallite size, and high specific surface area of the nano-doped-TiO2 photocatalysts depends on the presence of various dopants in the photocatalysts. The majority of the dopants have the potential to improve the photocatalytic efficiency of nano-doped-TiO2 in the degradation of organic pollutants. The photocatalytic degradation of organic compounds depends on the calcination temperature of the prepared doped TiO2, initial reactant concentration, dosage of doped TiO2, and dopant doping concentration.
Risk Stratification by Cardiac Biomarkers following Emergency Gastrointestinal Surgery
Authors: Cahill T. J. , Bowes P. , Duncan E. , Drye E. , Sen S. , Miller C. , Reshamwalla S. , Andrew C. , Ward M. , Bakhai A.
Published: December 2011

Perioperative cardiac complications are a major cause of death following emergency gastrointestinal surgery. Early diagnosis of subclinical myocardial injury and infarction may be improved by screening with cardiac biomarkers. The aim of this study was to assess the predictive value of troponin I (TnI) and B-type natriuretic peptide (BNP) in the early postoperative period after emergency gastrointestinal surgery. We prospectively recruited 48 patients undergoing major emergency surgery for gastrointestinal or colorectal pathology in a single district general hospital. The primary endpoint was mortality at 90 days following surgery. Overall survival was 81.3% (39/48), with 9 postoperative deaths. Elevated TnI (≥0.03 ng ) was the best predictor of mortality, associated with an odds ratio of death by 90 days of 14.3 (95% CI 1.50–337, ). A postoperative BNP concentration >408.5 pg  was associated with an odds ratio of death by 90 days of 13.6 (95% CI 2.03–106, ). A single measurement of postoperative BNP and TnI is a powerful predictor of short- to medium-term mortality in patients after emergency gastrointestinal surgery. Further work is required to demonstrate that cardiac biomarkers have independent predictive power and that patient outcomes can be improved.
Oromandibular Reconstruction: The History, Operative Options and Strategies, and Our Experience
Authors: Lin Pao-Yuan , Lin Kevin C. , Jeng Seng-Feng
Published: December 2011

Oromandibular reconstruction resulting from resection of benign tumor, malignant cancer, osteomyelitic or osteoradionecrotic mandible remains a challenge for plastic surgeons today. At present, fibula osteocutaneous flap is the perhaps most commonly used technique for oromandibular reconstruction because of its potential for contouring, immediate dental implant placement, and favorable donor site morbidity. In this study, we review the history of oromandibular reconstruction, summarize the characteristics of different osteocutaneous flaps, offer surgical options of different osteocutaneous flaps, and provide reconstructive strategies for different locations of mandibular defects. Furthermore, we give a detailed description of various modifications in oromandibular reconstruction: (1) the myoosseous flap for lateral segmental defect repair may reduce donor site complication; (2) to improve the function of oral commissure in patients with obscure recipient vessels, we modify the fibula osteocutaneous flap with anterolateral thigh flap and combine the tensor fascia lata using one set of recipient vessel for composite oromandibular reconstruction; (3) to decrease the likelihood of neck infection and improve aesthetic result, we add the segmental soleus muscle to the fibula osteocutaneous flap to obliterate and augment submandibular dead space. Lastly, dental rehabilitation considerations associated with mandibular reconstruction have been given to help assist in surgical treatment planning.
Determination of Astaxanthin in Haematococcus pluvialis by First-Order Derivative Spectrophotometry
Authors: Liu Xiao Juan , Wu Ying Hua , Zhao Li Chao , Xiao Su Yao , Zhou Ai Mei , Liu Xin
Published: December 2011

A highly selective, convenient, and precise method, first-order derivative spectrophotometry, was applied for the determination of astaxanthin in Haematococcus pluvialis. Ethyl acetate and ethanol (1:1, v/v) were found to be the best extraction solvent tested due to their high efficiency and low toxicity compared with nine other organic solvents. Astaxanthin coexisting with chlorophyll and β-carotene was analyzed by first-order derivative spectrophotometry in order to optimize the conditions for the determination of astaxanthin. The results show that when detected at 432 nm, the interfering substances could be eliminated. The dynamic linear range was 2.0–8.0 μg/mL, with a correlation coefficient of 0.9916. The detection threshold was 0.41 μg/mL. The RSD for the determination of astaxanthin was in the range of 0.01–0.06%; the results of recovery test were 98.1–108.0%. The statistical analysis between first-order derivative spectrophotometry and HPLC by T-testing did not exceed their critical values, revealing no significant differences between these two methods. It was proved that first-order derivative spectrophotometry is a rapid and convenient method for the determination of astaxanthin in H. pluvialis that can eliminate the negative effect resulting from the coexistence of astaxanthin with chlorophyll and β-carotene.
High-Performance Column Liquid Chromatographic Method for the Simultaneous Determination of Buclizine, Tryptophan, Pyridoxine, and Cyanocobalamin in Tablets and Oral Suspension
Authors: Kuminek Gislaine , Stulzer Hellen K , Tagliari Monika P , Oliveira Paulo R , Bernardi Larissa S , Rauber Gabriela S , Cardoso Simone G
Published: December 2011

An HPLC method was developed and validated for the simultaneous determination of buclizine, tryptophan, pyridoxine, and cyanocobalamin in pharmaceutical formulations. The chromatographic separation was carried out on an RP-C18 column using a mobile phase gradient of methanol, 0.015 M phosphate buffer (pH 3.0), and 0.03 M phosphoric acid at a flow rate of 1.0 mL/min and UV detection at 230, 280, and 360 nm, respectively, for buclizine, tryptophan, pyridoxine, and cyanocobalamin. The method validation yielded good results with respect to linearity (r > 0.999), specificity, precision, accuracy, and robustness. The RSD values for intraday and interday precision were below 1.82 and 0.63%, respectively, and recoveries ranged from 98.11 to 101.95%. The method was successfully applied for the QC analysis of buclizine, tryptophan, pyridoxine, and cyanocobalamin in tablets and oral suspension.
Sensitive Detection of Soy (Glycine max) by Real-Time Polymerase Chain Reaction Targeting the Mitochondrial atpA Gene
Authors: Bauer Tobias , Kirschbaum Katja , Panter Silvia , Kenk Marion , Bergemann Jörg
Published: December 2011

Detection of trace amounts of allergens is essential for correct labeling of food products by the food industry. PCR-based detection methods currently used for this purpose are targeting sequences of DNA present in the cell nucleus. In addition to nuclear DNA, a substantial amount of mitochondrial DNA (mtDNA) copies are present in the cytoplasm of eukaryotic cells. The nuclear DNA usually consists of a set of DNA molecules present in two copies per cell, whereas mitochondrial DNA is present in a few hundred copies per cell. Thus, an increase in sensitivity can be expected when mtDNA is used as the target. In this study, we present a reporter probe-based real-time PCR method amplifying the mitochondrial gene of the alpha chain of adenosine triphosphate synthetase from soy. Increase in sensitivity was examined by determining the minimal amount of soy DNA detectable by mtDNA and nuclear DNA (nDNA) amplification. Additionally, the LOD of soy in a food matrix was determined for mtDNA amplification and compared to the LOD determined by nDNA amplification. As food matrix, a model spice spiked with soy flour was used. Sensitivity of PCR-based soy detection can be increased by using mtDNA as the target.
Differentiation Between Sulfoaildenafil and Its Analogs
Authors: Moriyasu Takako , Minowa Keiko , Sakamoto Miho , Kishimoto Kiyoko , Kadoi Hideo , Nakajima Jun'ichi , Mori Ken'ichiro , Ogino shuzo , Fukaya Haruhiko , Shida Yasuo
Published: December 2011

An analog of aildenafil, which is a potent and highly selective inhibitor of phosphodiesterase 5, was found in a dietary supplement marketed for enhancement of sexual function. The compound was isolated by silica gel column chromatography, and its structure was identified by means of 13C-NMR spectrometry, 1H-NMR spectrometry, high-resolution MS, and X-ray structure determination. The compound was identified to be sulfoaildenafil (other names: thioaildenafil, dimethyl sildenafil thione, and thiomethisosildenafil). Sulfoaildenafil is very similar to the compound thiohomosildenafil. As it is difficult to distinguish between them by LC-photodiode array detector analysis, ultra-performance LC (UPLC)/MS, ion trap LC/MS/MS (LC/IT-MS/MS), and GC/MS were performed. The mass spectra of thiohomosildenafil by UPLC/MS and LC/IT-MS/MS showed mass fragments of m/z 58, 72, and 355, and the mass spectrum by GC/MS showed mass fragments of m/z 56, 72, and 420. Some of these fragments had low intensities, but they were useful for distinguishing between the two compounds. The relationship between aildenafil (other names: dimethylsildenafil and methisosildenafil) and homosildenafil is similar to that between sulfoaildenafil and thiohomosildenafil. Therefore, these were also examined.
Evaluation of VIDAS®Salmonella (SLM) Easy Salmonella Method for the Detection of Salmonella in a Variety of Foods: Collaborative Study
Authors: Crowley Erin , Bird Patrick , Fisher Kiel , Goetz Katherine , Benzinger M Joseph , Agin James , Goins David , Johnson Ronald L ,   Collaborators:, Andrews H , Brown M , Calimlim P , Cohen A , Colón-Reveles J , Dwivedi H , Fedio W , Glover J , Hanson P , Hernandez J , Hu J , Kelly M , Kim S , Mangione K , Manner K , McDonough M , Mills J , Murphy M , Nogle J , Okolo C , Olsen P , Pickett M , Sauders B , Sciulli R , Segarra M , Simpson S , Stevens C , Zapata R
Published: December 2011

The VIDAS®Salmonella (SLM) Easy Salmonella method is a specific enzyme-linked fluorescent immunoassay performed in the automated VIDAS instrument. The VIDAS Easy Salmonella method is a simple 2-step enrichment procedure, using pre-enrichment followed by selective enrichment in a newly formulated broth, SX2 broth. This new method was compared in a multilaboratory collaborative study to the U.S. Food and Drug Administration's Bacteriological Analytical Manual, Chapter 5 method for five food matrixes (liquid egg, vanilla ice cream, spinach, raw shrimp, and peanut butter) and the U.S. Department of Agriculture's Microbiology Laboratory Guidebook 4.04 method for deli turkey. Each food type was artificially contaminated with Salmonella at three inoculation levels. A total of 15 laboratories representing government, academia, and industry, throughout the United States, participated. In this study, 1583 samples were analyzed, of which 792 were paired replicates and 791 were unpaired replicates. Of the 792 paired replicates, 285 were positive by both the VIDAS and reference methods. Of the 791 unpaired replicates, 341 were positive by the VIDAS method and 325 were positive by the cultural reference method. A Chi-square analysis of each of the six food types was performed at the three inoculation levels tested. For all foods evaluated, the VIDAS Easy SLM method demonstrated results comparable to those of the reference methods for the detection of Salmonella.
Evaluation of Relevant Time-of-Flight-MS Parameters Used in HPLC/MS Full-Scan Screening Methods for Pesticide Residues
Authors: Mezcua Milagros , Malato Octavio , Martinez-Uroz Maria Angeles , Lozano Ana , Agüera Ana , Fernández-Alba Andamadeo R
Published: December 2011

An automatic screening method based on HPLC/time-of-flight (TOF)-MS (full scan) was used for the analysis of 103 non-European fruit and vegetable samples after extraction by the quick, easy, cheap, effective, rugged, and safe method. The screening method uses a database that includes 300 pesticides, their fragments, and isotopical signals (910 ions) that identified 210 pesticides in 78 positive samples, with the highest number of detection being nine pesticides/sample. The concentrations of 97 pesticides were <10 μg/kg, 53 were between 10 and 100 μg/kg, and 60 were at a concentration of >100 μg/kg. Several parameters of the automatic screening method were carefully studied to avoid false positives and negatives in the studied samples; these included peak filter (number of chromatographic peak counts) and search criteria (retention time and error window). These parameters were affected by differences in mass accuracy and sensitivity of the two HPLC/TOF-MS systems used with different resolution powers (15 000 and 7500), the capabilities of which for resolving the ions included in the database from the matrix ions were studied in four matrixes, viz., pepper, rice, garlic, and cauliflower. Both of these mass resolutions were found to be satisfactory to resolve interferences from the signals of interest in the studied matrixes.
Copper‐Catalyzed Azide–Alkyne Click Chemistry for Bioconjugation
Authors: Presolski Stanislav I. , Hong Vu Phong , Finn M.G.
Published: December 2011

The copper‐catalyzed azide‐alkyne cycloaddition reaction is widely used for the connection of molecular entities of all sizes. A protocol is provided here for the process with biomolecules. Ascorbate is used as reducing agent to maintain the required cuprous oxidation state. Since these convenient conditions produce reactive oxygen species, five equivalents of a copper‐binding ligand are used with respect to metal. The ligand both accelerates the reaction and serves as a sacrificial reductant, protecting the biomolecules from oxidation. A procedure is also described for testing the efficiency of the reaction under desired conditions for purposes of optimization, before expensive biological reagents are used. Curr. Protoc. Chem. Biol. 3:153‐162 © 2011 by John Wiley & Sons, Inc.
Analyzing In Vivo Metabolite‐Protein Interactions by Large‐Scale Systematic Analyses
Authors: Li Xiyan , Snyder Michael
Published: December 2011

Metabolites interact with proteins in vivo in various ways other than enzymatic reactions. Profiling of such interactions may help disclose unknown molecular mechanisms that regulate protein functions, and provide potential targets for disease treatment. Here a procedure is described for systematic analyses of metabolite‐protein interactions in vivo. This procedure couples protein affinity purification and mass spectrometry to identify metabolite‐protein interactions. The primary effort can be completed within 1 day and scaled to process hundreds of samples in a batch. Originally developed in yeast, the same principles and protocol can be adapted to other organisms. Curr. Protoc. Chem. Biol. 3:181‐196 © 2011 by John Wiley & Sons, Inc.
Americans with disabilities act as amended: Principles and practice
Authors: Bowman Lorenzo
Published: December 2011

As a result of the amendments to the Americans with Disabilities Act and its parallel revisions to Section 504 of the Rehabilitation Act of 1973, plaintiffs are more likely to clear the disability hurdle; therefore, we can expect to see much more litigation in the future focused on complex ADA issues regarding reasonable accommodations and undue hardship.
Moving forward: Two paradigms and takeaways
Authors: Rocco Tonette S.
Published: December 2011

Oppression of people with disabilities is subtle and often has a paternalistic subtext: Able‐bodied people know what is best for the person with a disability.
Improving Listening Skills in English as a Foreign Language by Reading Rather than Listening: A Cognitive Load Perspective
Authors: Moussa‐Inaty Jase , Ayres Paul , Sweller John
Published: December 2011

This study investigated the consequences of simultaneously reading and listening to the same materials when learning English as a foreign language. During acquisition, native Arabic‐speaking university students were asked to learn some English words and sentences either by reading them or by simultaneously reading and listening to the same spoken material. Following acquisition students were given reading, writing, and listening tests. The findings from the three experiments indicated that participants exposed to reading alone performed better on listening tests than participants exposed to a reading and listening condition. No differences were found on the reading and writing tests. The results, discussed within a cognitive load theory framework, suggest that at least some categories of learners will enhance their listening skills more by reading the materials only rather than simultaneously reading and listening. Copyright © 2011 John Wiley & Sons, Ltd.
Pregnancy in women diagnosed with Antineutrophil cytoplasmic antibody–associated vasculitis: Outcome for the mother and the child
Authors: Tuin J. , Sanders J. S. F. , de Joode A. A. E. , Stegeman C. A.
Published: December 2011

Objective

Antineutrophil cytoplasmic antibody–associated vasculitis (AAV) is infrequently seen in women of childbearing age. Only a limited number of pregnancies in women with AAV have been reported, and often they were associated with complications.

Methods

This was a single‐center retrospective observational study. All pregnancies in women with granulomatosis with polyangiitis (Wegener's) (n = 13) and microscopic polyangiitis (n = 1) were included. Women of childbearing age were counseled to abstain from pregnancy during or shortly after disease activity or <1 year after cyclophosphamide treatment.

Results

We described 22 pregnancies in 14 women with AAV (median age at diagnosis was 25 years [range 19–36 years]) diagnosed between 1982–2008. The ear, nose, and throat region (71%) and kidneys (50%) were predominantly involved. All women were in remission at conception and cyclophosphamide had been administered to 9 women (15 pregnancies). The median gestational age was 39+4 weeks, including 2 preterm deliveries. The median birth weight was 3,400 gm (1,860–3,890 gm). Hypothyroidism occurred in 1 newborn and a cleft palate in 1 newborn of a twin pregnancy. Otherwise, the fetal outcome was excellent. Preeclampsia was diagnosed in 2 pregnancies. A caesarean section was performed in 2 patients. The median followup after the last conception was 98 months (range 11–307 months). Eight women experienced a relapse 21 months (range 7–62 months) after conception, 1 during pregnancy, and 7 after delivery.

Conclusion

In this study, the pregnancy outcome in patients with AAV in remission was excellent. Pregnancy in women with AAV in remission does not seem to be associated with increased risk of relapse. Counseling, careful management, and close followup are essential in pregnant women with AAV.
“They didn't tell us, they made us work it out ourselves”: Patient perspectives of a cognitive–behavioral program for rheumatoid arthritis fatigue
Authors: Dures E. , Kitchen K. , Almeida C. , Ambler N. , Cliss A. , Hammond A. , Knops B. , Morris M. , Swinkels A. , Hewlett S.
Published: December 2011

Objective

Fatigue is an overwhelming rheumatoid arthritis (RA) symptom caused by interacting clinical and psychosocial factors. Cognitive–behavioral therapy (CBT) addresses links between thoughts, feelings, and behaviors and uses cognitive restructuring to facilitate behavior changes. In a randomized controlled trial, a group CBT program for RA fatigue improved fatigue impact, severity, and perceived coping, as well as mood and quality of life. The aim of this study was to explore the patient perspective of the program and the impact of behavior changes.

Methods

Ten exit focus groups were held (38 patients). Transcripts were analyzed by an independent researcher using a hybrid thematic approach, with a subset analyzed by a team member and patient partner.

Results

Three overarching themes were identified. In “they made us work it out ourselves” (program factors facilitating changes), patients spontaneously identified elements of group CBT as pivotal, including guided discovery, the impact of metaphors, and working as a group. In “feeling much better about yourself and coping much better” (the nature of changes), patients described cognitive changes, including enhanced self‐efficacy and problem solving, and emotional changes, including being less volatile and fearful of fatigue. In “my life has changed so much it's unbelievable” (benefits beyond fatigue), patients reengaged in previously abandoned activities, were more active, and enjoyed greater social participation.

Conclusion

Patients highlighted that CBT elements were key to making behavior changes and that these had far‐reaching impacts on their lives. This suggests it could be beneficial in clinical practice to incorporate cognitive–behavioral approaches into patient education programs that aim to enhance self‐management.
A Facile and General Method for the Encapsulation of Different Types of Imaging Contrast Agents Within Micrometer‐Sized Polymer Beads
Authors: Bai Meng‐Yi , Moran Christine H. , Zhang Lei , Liu Changjun , Zhang Yu , Wang Lihong V. , Xia Younan
Published: December 2011

Polystyrene (PS) hollow beads with holes on the surfaces are employed as containers for quick loading and encapsulation of a variety of contrast enhancement agents: saline solutions for thermoacoustic tomography, iodinated organic compounds for micro‐computed tomography, and perfluorooctane for magnetic resonance. Because of the hole on the surface of the PS hollow bead, the contrast agent to be encapsulated could quickly enter the hollow interior via direct flow rather than slow diffusion through the wall. After loading, the hole on the surface is conveniently sealed by annealing the sample at a temperature (e.g., 95 °C) slightly above the glass‐transition temperature of PS. In vitro methods are also used to investigate the effectiveness of encapsulation by quantifying the contrast enhancement enabled by the contrast agents.
Aqueous nitrate removal by D417 resin: thermodynamic, kinetic and response surface methodology studies
Authors: Ma Jinxing , Wang Zhiwei , Wu Zhichao , Wei Tianye , Dong Ying
Published: December 2011

In this study, D417 resin was characterized using scanning electron microscopy, Fourier transform infrared spectrometry and thermogravimetric analysis (TGA). Batchwise experiments were carried out to evaluate the thermodynamic and kinetic behaviors of the aqueous nitrate adsorption onto D417 resin. Response surface methodology (RSM) with Box–Behnken design (BBD) was employed to analyze the competition disturbance and matrix effects in terms of pH, organic matter concentration, contact time (CT) and salinity. Test results revealed that the resin was composed of the quaternary ammonium functional group and exhibited a considerable adsorption capacity of 23.46 to 22.81 mg·g−1 at the temperature ranging from 293.15 to 313.15 K. Mean free energy of adsorption calculated from the Dubinin–Radushkevich model showed that the adsorption was realized through ion‐exchange pathway. Gibbs free energy change, enthalpy change and entropy change illustrated that the aqueous nitrate sorption was feasible and spontaneous. It was also found that the pseudo‐second‐order model could well describe the adsorption kinetics, and the intraparticle diffusion was the main rate‐limiting step. RSM with BBD showed that CT and salinity had significant effects on aqueous nitrate adsorption, whereas the impacts of pH and dissolved organic matter were negligible. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
A physical model for a quality control concept in injection molding
Authors: Lucyshyn Thomas , Kipperer Michael , Kukla Christian , Langecker Günter Rüdiger , Holzer Clemens
Published: December 2011

In this work, a model is presented, which is the basis of a quality control concept for the injection molding process. Contrary to statistical methods, this model uses physical dependencies of two quality parameters on four influencing parameters. The influences of holding pressure, holding time, melt temperature, and mold temperature on part mass and dimensions are described based on the fundamental material behavior such as pvT‐data or energy equation. Furthermore, the influence of viscosity changes is indirectly taken into account using the injection work. Assuming only small deviations of the influencing parameters around an optimized operating point, the four parameters are treated as being independent from each other. With this assumption, a product ansatz was chosen with different functions for each influencing factor. Applying basic algebra, the starting equation was transformed into a form that describes either the change in part mass or characteristic part dimensions as a function of the influencing factors. The final equation for the part mass contains six model parameters, whereas nine model parameters are necessary for the equation for the part length. To obtain those model parameters some systematic experiments are required. Once the parameters are known, the model is able to calculate the change of the target values when the influencing factors vary around the operating point. The model was tested experimentally with focus on dimensions using a plastic cover made of an acrylonitrile butadiene styrene (ABS) grade. For the investigated part geometry and material grade, the process behavior was described well by the model. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polyindene/organo‐montmorillonite conducting nanocomposites. II. electrorheological properties
Authors: Guzel Serkan , Erol Ozlem , Unal H. Ibrahim
Published: December 2011

In this study, polyindene (PIn) and three PIn/organo‐montmorillonite (O‐MMT) nanocomposites namely K1: [PIn(94.5%)/O‐MMT(5.5%)], K2: [PIn(92.8%)/O‐MMT(7.2%)], and K3: [PIn(87.9%)/O‐MMT(12.1%)] were used to investigate the electrorheological (ER), creep‐recovery, and vibration damping characteristics. A volume fraction series (φ = 5–25%) of suspensions were prepared from the samples in silicone oil (SO). First, zeta (ζ)‐potentials and antisedimentation stabilities; second, ER properties of these nanocomposite/SO suspension systems were determined under externally applied electric field strengths. Besides, the effects of dispersed phase volume fraction, shear rate, electric field strength, and temperature onto ER performance of these suspensions were investigated and non‐Newtonian rheological behaviors were observed. The vibration damping capabilities of the suspensions were investigated using various rheological parameters on the electrorheometer and on an automobile shock absorber and a 66% vibration damping capacity were determined under an applied electric field strength, which is an important property from industrial point of view. Furthermore, the materials were subjected to creep and creep‐recovery tests and reversible viscoelastic deformations were determined. From the experiments carried out, the nanocomposites were classified as smart materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Determination of optimal production parameters for polyacrylonitrile nanofibers
Authors: Kirecci Ali , Özkoç Ümran , İçoğlu H. İbrahim
Published: December 2011

The object of this work is to determine the most suitable values of process and solution parameters for electrospinning of polyacrylonitrile (PAN) nanofibers including solution concentration, applied voltage, and working distance between the needle tip and the collector plate. To investigate the effects of those parameters on the fiber morphology, nanofiber mat samples were produced by changing the value of parameters systematically. The scanning electron microscope images of these samples were analyzed to realize the effects of these parameters on the nanofiber morphology. Our results demonstrate that the diameter of the fibers increases with increasing concentration. However, the diameter reduces as the applied voltage and working distance between needle tip and the collector increase up to a certain value. In addition to this, viscosity and applied voltage have a strong effect on the uniformity and morphology of the nanofibers. Moreover, a relationship between spinning distance, voltage supplied, solution concentration, charge density, bead formation, and the diameter of the electrospun PAN nanofiber were established in the study. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Melt characteristics, mechanical, and thermal properties of blown film from modified blends of poly(butylene adipate‐co‐terephthalate) and poly(lactide)
Authors: Sirisinha Kalyanee , Somboon Wanchana
Published: December 2011

Blown films from poly(butylene adipate‐co‐terephthalate) and poly(lactide) (PLA) blends were investigated. The blends were prepared in a twin‐screw extruder, in the presence of small amounts of dicumyl peroxide (DCP). The influence of DCP concentration on film blowing, rheological, mechanical, and thermal properties of the blends is reported in this article. Rheological results showed a marked increase in polymer melt strength and elasticity with the addition of DCP. As a consequence, the film homogeneity and the stability of the bubble were improved. The modified blend films, compared with the unmodified blend, showed an improvement in tensile strength and modulus with a slight loss in elongation. Fourier transform infrared and gel results revealed that chain scission and branching were more significant than crosslinking when the DCP loadings in the blends were not higher than 0.7%. A reduction in melt temperatures of PLA was observed due to difficulty in chain crystallization. The concentrations of DCP strongly affected the melting temperatures but had an insignificant effect on the decomposition behavior of the blends. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Optimized process for the inclusion of carbon nanotubes in elastomers with improved thermal and mechanical properties
Authors: Cadambi Rahul M. , Ghassemieh Elaheh
Published: December 2011

The effects of addition of reinforcing carbon nanotubes (CNTs) into hydrogenated nitrile–butadiene rubber (HNBR) matrix on the mechanical, dynamic viscoelastic, and permeability properties were studied in this investigation. Different techniques of incorporating nanotubes in HNBR were investigated in this research. The techniques considered were more suitable for industrial preparation of rubber composites. The nanotubes were modified with different surfactants and dispersion agents to improve the compatibility and adhesion of nanotubes on the HNBR matrix. The effects of the surface modification of the nanotubes on various properties were examined in detail. The amount of CNTs was varied from 2.5 to 10 phr in different formulations prepared to identify the optimum CNT levels. A detailed analysis was made to investigate the morphological structure and mechanical behavior at room temperature. The viscoelastic behavior of the nanotube filler elastomer was studied by dynamic mechanical thermal analysis (DMTA). Morphological analysis indicated a very good dispersion of the CNTs for a low nanotube loading of 3.5 phr. A significant improvement in the mechanical properties was observed with the addition of nanotubes. DMTA studies revealed an increase in the storage modulus and a reduction in the glass‐transition temperature after the incorporation of the nanotubes. Further, the HNBR/CNT nanocomposites were subjected to permeability studies. The studies showed a significant reduction in the permeability of nitrogen gas. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
A polymer–drug conjugate for doxorubicin: Synthesis and biological evaluation of pluronic F127‐doxorubicin amide conjugates
Authors: Gao Qihe , Han Xuelian , Zhu Jin , Chen Renjie , Sun Baiwang
Published: December 2011

Higher molecular weight of the polymer carrier is the basis for enhanced accumulation of the pro‐drug in a solid tumor tissue due to a tumor‐related phenomenon described as the enhanced permeability and retention (EPR) effect. The anticancer drug doxorubicin was covalently bound to F127 through amide group susceptible to lysosomal hydrolysis. The in vitro and in vivo properties of F127‐DOX amide conjugates were studied. F127‐DOX amide conjugates (Mw: 13,400) were stable in neutral circumstance and showed the potency and mechanism of action of the released drug. In the in vivo experiment, results showed that F127‐DOX amide conjugates prolonged blood circulation and lowered in vivo toxicity than corresponding DOX, which illustrated the importance of molecular weight. The results demonstrated that F127‐DOX amide conjugates may be very promising and clinically suitable candidates for anticancer therapy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Salinity effects on the degree of hydrophobicity and longevity for superhydrophobic fibrous coatings
Authors: Ochanda Fredrick O. , Samaha Mohamed A. , Tafreshi Hooman Vahedi , Tepper Gary C. , Gad‐el‐Hak Mohamed
Published: December 2011

Previous studies on submerged superhydrophobic surfaces focused on performance variables such as drag reduction and longevity. However, to use such surfaces for practical applications, environmental factors such as water salinity must be investigated and understood. In this work, experiments were carried out to investigate the impact of salt (sodium chloride, NaCl) concentrations in aqueous solutions on the hydrophobicity and longevity of polystyrene (PS) fibrous coatings. Rheological studies using salt water as a test fluid were performed to determine the effect of salt concentration on drag reduction. Contact‐angle measurements were used to validate the results from the rheometer. In situ noninvasive optical reflection was used to measure the longevity of the coating—time‐dependent loss of entrapped air within the coating—as a function of salinity. The superhydrophobic coating used herein consisted of PS fibers that were deposited using DC‐biased AC‐electrospinning. Electrospinning is scalable and far less expensive than conventional methods (e.g., microfabrication), bringing the technology closer to large‐scale submerged bodies such as submarines and ships. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Toughness enhancement of poly(lactic acid) by melt blending with natural rubber
Authors: Jaratrotkamjorn Ruedee , Khaokong Chuanpit , Tanrattanakul Varaporn
Published: December 2011

Rubber toughened poly(lactic acid) (PLA) was prepared by blending with natural rubber (NR)‐based polymers. The blends contained 10 wt % of rubber and melt blended with a twin screw extruder. Enhancement of impact strength of PLA was primarily concernced. This study was focused on the effect of rubber polarity, rubber viscosity and molecular weight on mechanical properties of the blends. Three types of rubbers were used: NR, epoxidized natural rubber (ENR25 and ENR50), and natural rubber grafted with poly(methyl methacrylate) (NR‐g‐PMMA). Effect of viscosity and molecular weight of NR, rubber mastication with a two‐roll mill was investigated. It was found that all blends showed higher impact strength than PLA and NR became the best toughening agent. Viscosity and molecular weight of NR decreased with increasing number of mastication. Impact strength of PLA/NR blends increased after applying NR mastication due to appropriate particle size. DMTA and DSC characterization were determined as well. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thiolated chitosans: In vitro comparison of mucoadhesive properties
Authors: Mueller Christiane , Verroken Andrea , Iqbal Javed , Bernkop‐Schnuerch Andreas
Published: December 2011

The aim of this study was to compare the mucoadhesive properties of thiolated chitosans with regard to their molecular mass and type of immobilized thiol ligand. Mediated by a carbodiimide, aromatic‐ and aliphatic‐thiol‐bearing compounds were covalently attached to low‐ and medium‐molecular‐mass chitosan. All synthesized conjugates displayed on average 320 ± 50 μmol of immobilized free thiol groups per gram of polymer. The rheological synergy was observed by the mixture of equal volumes of polymer with mucin solution. Because of the increase in viscosity of the conjugate/mucin mixture, the self‐crosslinking properties and the interaction of thiomers with the mucus layer could be confirmed. Further mucoadhesion of the chitosan conjugates was evaluated in vitro with the rotating cylinder method and tensile studies on excised porcine intestinal mucosa. The results show a significantly enhanced residence time (p < 0.05) on the mucosa of all thiolated chitosans compared to the unmodified polymer. Among all of the conjugates tested, the following rank order of mucoadhesion could be determined: Chitosan–thiobutylamidine > Chitosan–4‐mercaptobenzoic acid > Chitosan–glutathione > Chitosan–6‐mercaptonicotinic acid > Chitosan–N‐acetyl cysteine > Chitosan–thioglycolic acid > Unmodified chitosan. The charge, pKa, and reactivity of the attached compounds were found to be important factors influencing the mucoadhesive potential of the polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Vulcanization behavior and mechanical properties of organoclay fluoroelastomer nanocomposites
Authors: Lakshminarayanan Sriram , Gelves Genaro A. , Sundararaj Uttandaraman
Published: December 2011

The vulcanization behavior and mechanical properties of clay/fluoroelastomer nanocomposites produced by melt‐mixing of Dyneon FPO 3741 (a terpolymer of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene) with 10 phr of unmodified montmorillonite (CloisiteNA) or di(hydrogenated tallow‐alkyl) dimethyl ammonium‐modified montmorillonites (Cloisite15A and Cloisite20A) were studied. The properties of clay/FKM nanocomposites were compared with composites prepared using 10 and 30 phr of carbon black. The effects of clay surfactant and surfactant concentration on the vulcanization behavior, mechanical, and dynamical properties of peroxide cured composites were studied. XRD results of cured composites showed a decrease in d‐spacing and indicated deintercalation of the clays after the vulcanization process. It was also found that organoclays retard the FKM peroxide vulcanization process. Significantly, higher maximum torque on vulcanization was obtained with organoclays versus unmodified clay and carbon black. Although the morphologies of organoclay/FKM nanocomposites studied by XRD and TEM suggest similar intercalated/exfoliated structures, the organoclay with the lowest concentration of surfactant (95 meq/100 g clay) resulted in the highest increase in torque, modulus, hardness, and tear strength in the clay/FKM nanocomposites. It was also found that organoclays can increase both the hydrodynamic reinforcement and hysteresis loss of FKM nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Poly(N‐isopropylacrylamide) hydrogel: Effect of hydrophilicity on controlled release of ibuprofen at different pH
Authors: Francis Raju , Baby Deepa K. , Kumar D. Sakthi
Published: December 2011

Stimuli‐sensitive drug delivery systems (DDSs) have attracted considerable attention in medical and pharmaceutical fields; thermo‐sensitive DDS dealing with poly(N‐isopropylacrylamide) (PNIPAM) have been widely studied. Hydrogels composed of temperature‐sensitive NIPAM and biocompatible and pH‐sensitive maleic acid (MAc) were synthesized by sedimentation polymerization. Experiments on drug release from the crosslinked NIPAM‐co‐MAc hydrogel loaded with ibuprofen into different pH buffer solutions were successfully carried out at temperature swing between 25 and 40°C. The in vitro release studies have showed that the release rate depended on acidity or basicity (polarity) of the medium and the gel and swelling ratio of the gel network as a function of the environmental pH and temperature. The SEM image of the dry bead gave more insight into the surface architecture and the thermal studies shine light on the decomposition pattern and glass transition temperature of the gel. The mechanism of the drug release was discussed in relation to the diffusion rate and the abrupt change in the pH of the medium. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Removal of pyridine from water by pervaporation using crosslinked and filled natural rubber membranes
Authors: Singha N. R. , Ray S. K.
Published: December 2011

Natural rubber (NR) of grade RSS4 was efficiently cured (crosslinked) by using sulfur: accelerator weight ratio of 1 : 4. This was further compounded with high abrasion grade carbon black filler (grade N330) with three different doses, that is, 5, 10, and 20 wt % of rubber to form three different filled and crosslinked membranes designated as NR5, NR10, and NR20, respectively. These filled rubber membranes and one unfilled but efficiently cured membrane, that is, NR0, were used for pervaporative removal of low concentration of pyridine from water. The filled membranes were found to show higher pyridine selectivity but lower flux than the unfilled membrane. All of these membranes showed reasonably good range of flux and pyridine selectivity. Among all of the used membranes, NR5‐filled membrane yielded high pyridine selectivity (122) with reasonable thickness normalized flux (2.2 kg m−2 h−1 mμ) at 40°C for 0.5 wt % of pyridine in water. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Association between systemic antipsoriatic drugs and cardiovascular risk in patients with psoriasis with or without psoriatic arthritis: A nationwide cohort study
Authors: Chen Yi‐Ju , Chang Yun‐Ting , Shen Jui‐Lung , Chen Tzu‐Ting , Wang Chang‐Bi , Chen Chuan‐Mu , Wu Chun‐Ying
Published: December 2011

Objective

Psoriasis is associated with ischemic heart disease (IHD). Results of prior studies have suggested that methotrexate (MTX) may improve vascular disease in patients with psoriasis and rheumatoid arthritis. The aim of this study was to assess the risk of new‐onset IHDs in psoriasis patients, comparing those taking MTX with those taking other nonbiologic antipsoriatic drugs.

Methods

In this retrospective cohort study, we utilized claims data from the National Health Insurance Research Database of Taiwan to identify 179,200 subjects who had received a diagnosis of psoriasis, with or without psoriatic arthritis, on at least 3 visits. The risk of hospitalization for new‐onset IHD was compared between psoriasis patients taking MTX monotherapy (n = 6,578; MTX case cohort) and psoriasis patients taking other nonbiologic antipsoriatic drugs (n = 5,471; reference control cohort) between January 1996 and December 2008. Additional adjustments were made for cardiovascular risk factors, number of hospital visits, Charlson comorbidity score, and use of other antiinflammatory drugs.

Results

The incidence rates of IHD were 666 cases per 100,000 person‐years in the MTX case cohort and 830 cases per 100,000 person‐years in the reference control cohort (unadjusted P = 0.027). Increasing age, male sex, presence of hypertension, presence of diabetes, Charlson comorbidity score, and use of phototherapies were independent risk factors for hospitalization related to a new IHD in the study cohorts. However, the multivariate‐adjusted hazard ratio for IHD‐related hospitalizations among patients receiving MTX, in comparison with those receiving other nonbiologic antipsoriatic drugs, was 0.97 (95% confidence interval 0.79–1.19), after adjustment for age, sex, comorbidity score, number of hospital visits, and other antiinflammatory treatments for psoriasis.

Conclusion

In patients with psoriasis with or without coexisting psoriatic arthritis, the adjusted risk of hospitalization for an IHD among individuals receiving MTX was comparable with that among individuals receiving other nonbiologic antipsoriatic drugs.
Magnetic chemically peculiar stars: Results of CCD magnetic field measurements with the 6‐m telescope
Authors: Romanyuk I.I.
Published: December 2011

We present a survey of observational data on the magnetic fields and physical parameters of chemically peculiar (CP) stars for the past 15–20 years. It appears that the traditional notions on chemically peculiar stars as very stable objects with frozen atmospheres are in need of revision. Analysis of new high‐precision observational data allows to detect such subtle phenomena as pulsations of brightness and radial velocities of stars, and the vertical stratification of chemical elements in their atmospheres. A relationship was found between weak anomalies in the energy distribution in the continuum and the magnetic field strength. An analysis of the Stokes Q and U parameter line profiles of some stars has shown that these observations can be described under the assumption of the field of complex topology, which can not be represented in the form of low‐order multipoles. We found large vertical gradients from lines formed at different optical depths in the stellar atmospheres. These facts indicate much more complex atmospheric structures in chemically peculiar stars than was considered only 20 years ago (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)