bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvement of compatibility of poly(ethylene terephthalate) and poly(ethylene octene) blends by γ‐irradiation
Authors: Yin Yuan , Liu Meihua , Zheng Xiaowei , Shen Shirley Zhiqi , Deng Pengyang
Published: May 2012

Blends of poly(ethylene terephthalate) (PET) and poly(ethylene octene) (POE) were prepared by melt blending with various amounts of trimethylolpropane triacylate (TMPTA). The mechanical properties, phase morphologies, and gel fractions at various absorbed doses of γ‐irradiation have been investigated. It was found that the toughness of blends was enhanced effectively after irradiation as well as the tensile properties. The elongation at break for all studied PET/POE blends (POE being up to 15 wt %) with 2 wt % TMPTA reached 250–400% at most absorbed doses of γ‐irradiation, approximately 50–80 times of those of untreated PET/POE blends. The impact strength of PET/POE (85/15 wt/wt) blends with 2 wt % TMPTA irradiated with as little as 30 kGy absorbed dose exceeded 17 kJ/m2, being approximately 3.4 times of those of untreated blends. The improvement of the mechanical properties was supported by the morphology changes. Scanning electron microscope images of fracture surfaces showed a smaller dispersed phase and more indistinct inter‐phase boundaries in the irradiated blends. This indicates increased compatibility of PET and POE in the PET/POE blends. The changes of the morphologies and the enhancement of the mechanical properties were ascribed to the enhanced inter‐phase boundaries by the formation of complex graft structures confirmed by the results of the gelation extraction and Fourier Transform Infrared analyses. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of fiber treatment on the water absorption and mechanical properties of hemp fiber/polyethylene composites
Authors: Fang Haixia , Zhang Yaolin , Deng James , Rodrigue Denis
Published: May 2012

The hemp fiber/polyethylene (PE) composites were prepared by varying the fiber shape (hemp flour and hemp fiber from thermomechanical refining), coupling agent (maleic anhydride grafted and copolymerized onto PE), coupling agent loading method (during fiber treating process in the thermomechanical refiner and compositing process in twin screw extruder), and compositing method (twin screw extruding and batch mixing). The paper firstly measured the moisture absorption properties of the treated fibers. The introduction of coupling agent during fiber treating process decreased effectively the moisture uptake. Then, the water absorption and mechanical properties were investigated on the hemp/PE composites. The loading of coupling agent during fiber treating process decreased the water uptake but also decreased the flexural yield strength, consequently resulted in lower flexural yield strength after water exposure. The composites prepared by batch mixing method were better than by twin screw extruding for the water resistance and mechanical properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Kinetic study of the dehydrogenation reaction in polyacrylonitrile‐based carbon fiber precursors during thermal stabilization
Authors: Xue Yan , Liu Jie , Liang Jieying
Published: May 2012

The kinetics of dehydrogenation reaction and the structural evolution in polyacrylonitrile precursor fibers during thermal stabilization in air have been studied by Fourier transform infrared spectroscopy. The results indicate that, with the progress of dehydrogenation, the absorbance of methylene groups (CH2) gradually decreases, whereas that of methine groups (CH) gradually increases. The dehydrogenation reaction in the fibers is basically completed after 20‐min stabilization above 255°C. According to the Beer–Lambert law, the values of the absorbance for both CH2 groups and the resulting CH groups have been calculated and converted into the concentration fractions of CH2 groups via the Lorentzian multipeak fitting. According to the principles of chemical kinetics, the dehydrogenation reaction has been determined as a pseudo‐second‐order reaction with an activation energy of 107.6 kJ mol−1. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Spectroscopic and thermal characterization of the swelling behavior of nafion membranes in mixtures of water and methanol
Authors: Martinez‐Felipe A. , Imrie C. T. , Ribes‐Greus A.
Published: May 2012

The spectroscopic and thermal properties of swollen Nafion membranes in methanol aqueous mixtures were investigated to understand the behavior of commercial electrolytes in the presence of polar solvents. Several differences were observed in the absorption processes depending on the composition of the solvent. Deconvolution methods were applied to study specific contributions of solvents and polymer groups based on Fourier transform infrared spectroscopy and thermogravimetric analysis. The results evidence compositional effects on the interactions between solvents and Nafion. A major influence of the nonpolar domains (hydrophobic regions) in the absorption of methanol together with a reduction of the interactions with sulfonate groups was observed. Such changes are accompanied by a modification of the cluster morphology of the equilibrated membranes evaluated by differential scanning calorimetry. These findings can be useful to improve the knowledge on Nafion's microstructure in the presence of polar solvents. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and gas transport properties of novel hyperbranched polyimide–silica hybrid membranes
Authors: Suzuki Tomoyuki , Yamada Yasuharu
Published: May 2012

Physical and gas transport properties of hyperbranched polyimide (HBPI)—silica hybrid membranes prepared with a dianhydride monomer, 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and triamine monomers, 1,3,5‐tris(4‐aminophenoxy)triazine (TAPOTZ), and 1,3,5‐tris(4‐aminophenyl)benzene (TAPB), were investigated and compared with those of 6FDA‐TAPOB HBPI system synthesized from 6FDA and 1,3,5‐tris(4‐aminophenoxy)benzene (TAPOB). Glass transition and 5% weight‐loss temperatures of the 6FDA‐based HBPI–silica hybrid membranes were increased with increasing silica content. 6FDA‐TAPOTZ HBPI system, however, showed relatively low 5% weight‐loss temperatures, suggesting thermal instability of triazine‐ring in the TAPOTZ moiety. CO2/CH4 permselectivity of the HBPI–silica hybrid membranes were increased with increasing silica content, tending to exceed the upper bound for CO2/CH4 separation. This result indicated that free volume elements effective for CO2/CH4 separation were created by the incorporation of silica for the HBPI–silica hybrid systems. Especially, 6FDA‐TAPB HBPI system had high gas permeabilities and CO2/CH4 separation ability, arising from high fractional free volume and characteristic size and distribution of free volume elements. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Aliphatic polycarbonate‐based polyurethane elastomers and nanocomposites. II. Mechanical, thermal, and gas transport properties
Authors: Poręba Rafał , Špírková Milena , Brožová Libuše , Lazić Nada , Pavličević Jelena , Strachota Adam
Published: May 2012

Thermal, thermomechanical, tensile and gas transport properties of aliphatic polycarbonate‐based polyurethanes (PC‐PUs) and their nanocomposites with bentonite for organic systems were studied. Hard segments are formed from hexamethylene diisocyanate and butane‐1,4‐diol. All PC‐PUs and their nanocomposites feature high degree of the phase separation. Three phase transitions were detected by temperature‐modulated differential scanning calorimetry (TMDSC) and dynamic mechanical thermal analysis. TMDSC revealed the filler affinity both to soft and hard segments, even though the affinity to hard segments is much stronger. Elongation‐at‐break at ambient temperatures is mostly over 700%, which leads together with high tensile strength (in some cases) to very high toughness values (over 200 mJ/mm3). The addition of 1 wt % of bentonite does not practically affect mechanical properties implying its very good incorporation into the PU matrix. Permeabilities and other gas transport properties depend on regularity of PC‐diol and on hard segment content, but the variations are insignificant. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of all para‐position polysulfonamide fiber
Authors: Li Humin , Zhu Yin , Xu Bing , Wu Chengxun , Zhao Jiongxin , Dai Mingxin
Published: May 2012

Poly(4,4′‐diphenylsulfone terephthalamide) referred to as all para‐position polysulfonamide (all para‐position PSA) is a special kind of PSAs, copolymers of 3,3′‐diaminodiphenylsulfone, 4,4′‐diaminodiphenylsulfone, and terephthaloyl chloride. However, with the increasing para‐structure content in the PSAs, the PSA shows very poor solubility in common amide‐type polar aprotic solvents and cannot be used for wet spinning. In this article, it was found that all para‐position PSA can be easily dissolved in N,N‐Dimethylacetamide (DMAc)/LiCl system, and then the all para‐position PSA fiber was prepared for the first time by wet spinning. The properties of all para‐position PSA pulps and fibers were investigated via Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), scanning electron microscopy, thermal gravimetric analysis, dynamical mechanical analysis, X‐ray diffraction (XRD), and tensile strength testing. The tensile strength, elongation at break, and crystallinity of the resulting fiber were 4.4 cN/dtex, 15.9%, and 33.53%, respectively. The results indicated that all para‐position PSA fiber was a high‐temperature resistance fiber with better mechanical properties than common PSA fiber. The improved tensile strength of the fiber will expand its applications and may take place of Nomex in certain fields and become a new generation of flame retardant and high‐temperature resistant material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Recycling of PET waste using 3‐amino‐1‐propanol by conventional or microwave irradiation and synthesis of bis‐oxazin there from
Authors: Shah Rikhil V. , Borude Vasant S. , Shukla Sanjeev R.
Published: May 2012

There is a growing interest in recycling of post‐consumer poly(ethylene terephthalate) (PET) waste for both environmental and economic reasons. PET in the form of disposable soft drink bottle waste was subjected to depolymerization via aminolysis using excess of 3‐amino‐1‐propanol under soxhlet by conventional heating as well as microwave irradiation using catalyst sodium acetate or potassium sulfate. The product obtained was characterized after purification by using melting point, IR spectroscopy, nuclear magnetic resonance, and differential scanning calorimeter and was found to be bis‐(3‐hydroxy propyl) terephthalamide (BHPTA). The BHPTA thus obtained was subjected to cyclization reaction using thionyl chloride to obtain bis‐oxazin under conditions of ambient temperature. Bis‐oxazin has applications in polymer synthesis as a chain extender or a cross linking agent. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Robust superhydrophilic coatings by electropolymerization of sulfonated pyrrole
Authors: Canterbury Daniel P. , Huang Kun , Xie Tao , Rzayev Javid
Published: May 2012

Superhydrophilic coatings were prepared by electropolymerization of sufonated pyrrole from aqueous solutions. The monomer was prepared in one step from commercially available reagents. Electropolymerized polymer films exhibited significant surface roughness and porosity as evidenced by scanning electron microscopy analysis. Advancing water contact angles of the pristine coatings were as low as 12°, while receding angles were 0° for almost all samples. Soaking the films in hot water resulted in decrease in the advanced contact angles to as low as 0°. The produced coatings retained their extreme wetting characteristics even when treated in harsh environments, such as dry heat for a week. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2012
Singapore's anatomical future: Quo Vadis?
Authors: Ang Eng‐Tat , Sugand Kapil , Hartman Mikael , Seow Choon‐Sheong , Bay Boon‐Huat , Abrahams Peter
Published: May 2012

The disciplines of anatomy and surgery are not dichotomous since one is dependent on the other. Traditionally, surgeons predominantly taught gross and clinical anatomy. In this review, we examine the context of how human anatomy is taught nowadays. In essence, we discovered that there are certain discernable trends consistently observable between the American and British systems. In Singapore, the British Russell Group first influenced its education landscape but now more so by the American Ivy League. Singapore now has three medical schools all offering differing anatomy curricula, which serves as an opportune time for it to consider if there is a best approach given that the practice of surgery is also evolving in parallel. This review discusses the various pedagogies and issues involved, and will serve as a forum and stimulus for discussion. By tweaking the curriculum correctly and the lessons learnt, future doctors and surgeons in training will receive a better anatomical education, not just in Singapore but the world in general. Key recommendations include the use of body painting, clay, plasticine to facilitate the learning of anatomy, and the implementation of a body donation program. Furthermore, strategic mergers with key stakeholders will also ensure the survival of the discipline. Anat Sci Educ. © 2012 American Association of Anatomists.
To what problem is distributed information retrieval the solution?
Authors: Thomas Paul
Published: May 2012

Distributed information retrieval (DIR), where a single broker coordinates retrieval from many independent search services, has been extensively studied but typically without any particular application and sometimes even without any explicit motivation. There have been a handful of arguments given for DIR—coverage, effectiveness, and ease of use, for example—but these are not borne out by experience.

Are there uses for DIR? There are, but generally for organizational not technical reasons, and they have not been well studied.
Graphene‐amplified electrogenerated chemiluminescence of CdTe quantum dots for H2O2 sensing
Authors: Wang Zhonghui , Song Hongjie , Zhao Huihui , Lv Yi
Published: May 2012

Electrogenerated chemiluminescence (ECL) of thiol‐capped CdTe quantum dots (QDs) in aqueous solution was greatly enhanced by PDDA‐protected graphene (P‐GR) film that were used for the sensitive detection of H2O2. When the potential was cycled between 0 and −2.3 V, two ECL peaks were observed at −1.1 (ECL‐1) and −1.4 V (ECL‐2) in pH 11.0, 0.1 M phosphate buffer solution (PBS), respectively. The electron‐transfer reaction between individual electrochemically‐reduced CdTe nanocrystal species and oxidant coreactants (H2O2 or reduced dissolved oxygen) led to the production of ECL‐1. While mass nanocrystals packed densely in the film were reduced electrochemically, assembly of reduced nanocrystal species reacted with coreactants to produce an ECL‐2 signal. ECL‐1 showed higher sensitivity for the detection of H2O2 concentrations than that of ECL‐2. Further, P‐GR film not only enhanced ECL intensity of CdTe QDs but also decreased its onset potential. Thus, a novel CdTe QDs ECL sensor was developed for sensing H2O2. Light intensity was linearly proportional to the concentration of H2O2 between 1.0 × 10−5 and 2.0 x 10‐7 mol L−1 with a detection limit of 9.8 x 10−8 mol L−1. The P‐GR thin‐film modified glassy carbon electrode (GCE) displayed acceptable reproducibility and long‐term stability. Copyright © 2012 John Wiley & Sons, Ltd.
Severe intraprosthetic regurgitation and valve embolization after transcatheter aortic valve implantation
Authors: Ben‐Dor Itsik , Satler Lowell F. , Pichard Augusto D. , Waksman Ron
Published: May 2012

Transcatheter aortic valve implantation is a novel therapeutic approach for high‐risk patients with severe symptomatic aortic stenosis. The success rate of this new procedure is high; however, procedural complications can occur and may result in devastating outcomes. Here, we report a case of transfemoral catheter aortic valve implantation using the Edwards SAPIEN valve complicated by severe intravalvular leak due to immobile cusp associated with shock. We treated with a second valve that embolized and deployed in the descending aorta. A third valve was then deployed within the first with elimination of aortic regurgitation and immediate hemodynamic improvement. © 2012 Wiley Periodicals, Inc.
Local delivery of sirolimus nanoparticles for the treatment of in‐stent restenosis
Authors: Zago Alexandre C. , Raudales José C. , Attizzani Guilherme , Matte Bruno S. , Yamamoto German I. , Balvedi Julise A. , Nascimento Ludmila , Kosachenco Beatriz G. , Centeno Paulo R. , Zago Alcides J.
Published: May 2012

Objectives

To test the local delivery of sirolimus nanoparticles following percutaneous transluminal coronary angioplasty (PTCA) to treat in‐stent restenosis (ISR) in a swine model.

Background

Coronary bare‐metal stent (BMS) implantation reduces major adverse cardiac events when compared with PTCA; however, ISR rates remain high.

Methods

Eighteen swine underwent BMS deployment guided by intravascular ultrasound (IVUS). Of these, 16 developed ISR (1 stent/swine) and underwent angioplasty with a noncompliant balloon (PTCA‐NC). The animals were then randomized into four groups for local infusion of sirolimus nanoparticles through a porous balloon catheter, as follows: (1) PTCA‐NC alone (control); (2) PTCA‐NC + (polylactic acid)‐based nanoparticle formulation (anionic 1); (3) PTCA‐NC + (polylactic‐co‐glycolic acid)‐based nanoparticle formulation (anionic 2); and (4) PTCA‐NC + Eudragit RS nanoparticle formulation (cationic). Coronary angiography and IVUS follow‐up were performed 28 days after ISR treatment.

Results

There was one episode of acute coronary occlusion with the cationic formulation. Late area loss was similar in all groups at 28 days according to IVUS. However, luminal volume loss (control = 20.7%, anionic 1 = 4.0%, anionic 2 = 6.7%, cationic = 9.6%; P = 0.01) and neointimal volume gain (control = 68.7%, anionic 1 = 17.4%, anionic 2 = 29.5%, cationic = 31.2%; P = 0.019) were significantly reduced in all treatment groups, especially in anionic 1.

Conclusions

PTCA‐NC followed by local infusion of sirolimus nanoparticles was safe and efficacious to reduce neointima in this model, and this strategy may be a promising treatment for BMS ISR. Further studies are required to validate this method in humans. © 2012 Wiley Periodicals, Inc.
Improvements to multivariate data analysis and monitoring of batch processes by multilevel methods
Authors: de Noord Onno E.
Published: May 2012

Batch process data contain between‐run and within‐run sources of variation, which complicates data analysis and process monitoring. Multilevel methods, such as multilevel simultaneous component analysis, greatly enhance the interpretation of large sets of batch process data by separating the between‐run and within‐run variation. Using a multilevel approach in batch process monitoring greatly reduces the occurrence of false alarms that are caused by trivial variations and process changes that were made on purpose. This also reduces the need for model updating, which often is a large effort and causes downtime of the monitoring system. Furthermore, relevant phenomena that are masked by larger but uninteresting sources of variation when standard batch process monitoring methods are applied can often be detected if the multilevel approach is used. Chemical batch process data are used to illustrate the methods. Copyright © 2012 John Wiley & Sons, Ltd.
Rest and exercise electrocardiograms and radionuclides in patients presenting for cardiac rehabilitation
Authors: Froelicher V. F. , Sebrechts C. , Streitwiesser D. , Battler A. , McKirnan M. D. , Ashburn W.
Published: May 2012

The rest and exercise ECG, 201thallium myocardial scintigram (201T1), and radionuclide ventriculography are noninvasive procedures which can be used to evaluate myocardial damage and ischemia. To compare these procedures and to obtain baseline information, 85 male patients with coronary heart disease were evaluated prior to beginning an exercise program. Findings at rest included Q waves or bundle branch block in 54%; 47% had 201T1 redistribution defects and 33% an abnormal ejection fraction (EF). Of the 39 patients with normal ECGs, 31 had no 201T1 defects and only 1 of these 31 (3%) had an abnormal EF. Abnormal EF or 201T1 redistribution defects did not occur in patients without a history of myocardial infarction. Abnormal resting EF occurred in 63% of patients with abnormal versus 7% of those with normal 201T1 redistribution scans. Exercise test results included an abnormal ST‐segment response in 80%, an abnormal EF response in 65%, and a 201T1 ischemic defect in 37%. Twenty patients had exercise‐induced ST elevation, and this phenomenon was more related to ventricular aneurysms than to ischemia. 201Thallium imaging, radionuclide ventriculography, and the ECG provide results regarding myocardial damage that agree by more than chance, while the exercise‐induced ST‐segment changes did not agree with the radionuclide indications of exercise‐induced ischemia.
Analysis of multiple noninvasive test procedures for the diagnosis of coronary artery disease
Authors: Charuzi Y. , Diamond G. A. , Pichler M. , Waxman A. , Vas R. , Silverberg R. A. , Berman D. S. , Forrester J. S.
Published: May 2012

All noninvasive tests used for the diagnosis of coronary artery disease are imperfect, both in sensitivity and in specificity. Accordingly, we evaluated the accuracy of four different diagnostic tests in various combinations in a population of 43 patients undergoing coronary angiography to determine if accuracy could be improved by multiple testing. These tests included stress electrocardiography for evaluation of exercise‐induced ST‐segment depression, stress cardio‐kymography (CKG) for detection of exercise‐induced precordial regional left ventricular dysfunction, stress 201thallium scintigraphy for assessment of exercise‐induced regional myocardial hypoperfusion, and cardiac fluoroscopy for detection of coronary artery calcification. A total of 46 (27%) of the 172 test responses observed were incorrect relative to angiography. These “false” responses were uniformly distributed over the four test procedures (12 ECG, 11 CKG, 10 201thallium, 13 fluoroscopy). Thus, a single test had a limited predictive accuracy for the detection or exclusion of coronary artery disease. The greater the number of abnormal responses observed in a given patient the greater the predictive accuracy for disease, especially multi‐vessel disease. Analysis of various combinations of these procedures revealed substantial differences both in cost of testing and net diagnostic yield. These data suggest that the four procedures employed are functionally independent and highly accurate relative to the diagnosis of coronary artery disease when used in combination. Cost‐effectiveness of diagnostic testing might be improved with the use of combinations of the less expensive and more accurate of these tests.
The Bezold—Jarisch reflex: Possible role in limiting myocardial ischemia
Authors: Robertson R. M. , Robertson D.
Published: May 2012

A patient with a 5‐year history of nonexertional episodic chest discomfort terminating in nausea presented with recurrent periods of marked ST elevations. Each observed episode terminated in the triad of bradycardia, hypotension, and nausea. ST Elevation normalized almost immediately when this triad supervened. It is hypothesized that this represented activation of the Bezold–Jarisch reflex. Resolution may have been due to reflexly mediated parasympathetic coronary vasodilation. An episode of ST elevation occurred 24 h after admission which did not result in activation of the Bezold–Jarisch reflex. Following this latter episode, Q waves and enzymatic evidence of myocardial infarction were documented.
Demonstration of multiple antegrade and retrograde atrioventricular pathways
Authors: Gmeiner R. , Ng C. K.
Published: May 2012

A patient with paroxysmal supraventricular tachycardia had discontinuous antegrade (A1‐A2, H1‐H2) and retrograde (V1‐V2, A1‐A2) conduction curves suggesting dual A‐V nodal pathways in both directions. Atrial echoes occurred with premature atrial pacing only at short A1‐A2 coupling intervals after long antegrade (A2‐H2) and retrograde (H2‐Ae) conduction intervals. Premature ventricular stimulation revealed ventricular echoes simultaneously with a sudden increase in the V2‐A2 interval. The echo zone coincided with the slow pathway curve. Following atropine the echo zone was extended over the slow and fast pathway curves. Slow pathway conduction was observed at long and short V1‐V2 coupling intervals, fast pathway conduction at intermediate V1‐V2 coupling intervals. Following isoproterenol premature ventricular stimulation initiated two cycles of ventricular echoes with relatively long retrograde (V2‐A2, Ve‐Ae) and short antegrade (A2‐He, Ac‐He) conduction times, the earliest atrial activation being observed in the low right atrium before the left atrium and the high right atrium.

Antegrade fast and slow pathway as well as retrograde fast pathway conduction appeared to be confined to the A‐V node. Retrograde slow pathway conduction may progress through a slow or fast A‐V nodal pathway slowed by antegrade concealed conduction. However, an accessory pathway with long conduction times located near the septum cannot be ruled out entirely.
A Kinetic Code System to Study Impurity Deposition and Fuel Retention in Gaps Between Divertor Tiles
Authors: Dai S. , Sang C. , Sun J. , Wang D.
Published: May 2012

For the purpose of investigating impurity deposition and fuel retention in gaps between divertor tiles, we combine a three‐dimensional Monte Carlo impurity transport code ITCD with a Particle‐In‐Cell Monte Carlo collision code plus a plasma‐surface interaction (PSI) code. The simulation results show that a potential hill formed near the entrance of the gap can prevent the ionized eroded carbon species from entering the gap. It is found that carbon sources for the co‐deposition in gaps are mainly located at the plasma‐closest edges of the gap, and this finding indicates that special measures associated with the engineering issues should be taken to minimize fuel retention in gaps. The smaller scale of carbon sources inside the gap and the existence of the potential hill near the entrance of the gap are the reasons why the eroded carbon species spatial density is lower inside the gap than outside the gap. Through the study on several scenarios with different substrate and plasma temperatures, the simulation with the combined code can deepen the understanding of fuel retention in the codeposited layers in gaps (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Classical Binary and Triplet Distribution Functions for Two Component Plasma
Authors: Eisa D. A.
Published: May 2012

The equilibrium properties of a multi‐component plasma of charged particles that interact through the coulomb and short‐range potentials are investigated. In particular, this article presents density expansions of the reduced distribution functions for more particles, our calculations are based on the Bogoliubov‐Born‐Green‐Kirkwood‐Yvon (BBGKY) hierarchy, we used the results to calculate the binary and triplet distribution functions. We obtained the analytical form of the classical triplet distribution functions for two component plasma; one of them is based on the Kirkwood superposition approximation (KSA) which is consisting of the assumption that the potential in a set of three particles is the sum of the three pair potentials, this is equivalent to assuming that the triplet distribution function is the product of the three radial distribution functions, and the other form is calculated by integration the triplet distribution function (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Paschen Curve and Film Growth in Low Pressure Capacitively Coupled Magnetron Plasma Polymerization
Authors: Ledernez L. , Olcaytug F. , Urban G.
Published: May 2012

The deposition of dielectric nanofilms by magnetron AF plasma polymerization between two planar electrodes shows a number of advantages over the standard RF method without magnetron enhancement. Because it is powered at 15 kHz, it works as a DC discharge swapping side every half cycle. We investigated here the effect of the magnetron on the breakdown voltage in our system taking Paschen curves with a DC power source. Subsequently, we related the Paschen curves with the deposition rate of the coating, showing that the Paschen minimum corresponds to the maximum growth rate as far as the pressure and the inter‐electrode distance are concerned. This result can be used to quickly determine the maximum growth rate in a given configuration via the measurement of a Paschen curve (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical Conductivity of Noble Gas Plasmas in the Warm Dense Matter Regime
Authors: Fu Z.J. , Chen Q.F. , Chen X.R.
Published: May 2012

The electrical conductivity of noble gas plasmas is investigated by using the relaxation‐time approximation in the density range 10–5–10 g cm–3 and temperature range 104–105 K. The electrical conductivity calculated shows reasonable consistency with shock wave experiments and theoretical simulations at above 2 × 104 K where the Coulomb interaction dominates. A nonmetal to metal transition in helium plasma is predicted at 2.4 g cm–3 and shown reasonable agreement with the most recent shock wave experiment (above 1.9 g cm–3). Furthermore, the insulator‐metal transition densities of all the noble gas plasmas are predicted and compared with available results (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The effect of purging on sexually selected traits through antagonistic pleiotropy with survival
Authors: Bolstad Geir H. , Pélabon Christophe , Larsen Line‐K. , Fleming Ian A. , Viken Åslaug , Rosenqvist Gunilla
Published: May 2012

Sexually selected traits are expected to evolve to a point where their positive effect on reproductive success is counterbalanced by their negative effect on survival. At the genetic level, such a trade‐off implies antagonistic pleiotropy between survival and the expression of sexually selected traits. Yet, the consequences of such a genetic architecture have been largely overlooked in studies examining how inbreeding influences sexually selected traits. These studies have solely interpreted their results as an effect of increased homozygosity. An alternative, however, is that purging of recessive alleles deleterious for survival when inbreeding increases can negatively affect the expression of sexually selected traits through antagonistic pleiotropy. We tested this hypothesis by analyzing the effects of inbreeding on several male ornaments and life‐history traits across 20 captive populations of guppies (Poecilia reticulata) with varying levels of inbreeding. Only one ornament, orange area, decreased in its expression with an increasing level of inbreeding. This was most likely due to purging because we found no within‐population relationship between orange area and the inbreeding coefficient. We further tested this hypothesis by crossing unrelated individuals from the four most inbred populations, creating a group of individuals with purged genomes but restored heterozygosity. Restoration of heterozygosity only slightly increased orange area, confirming that the decrease in orange area in the inbred populations most likely resulted from purging. These results support previous studies suggesting the existence of antagonistic pleiotropy between ornament expression and survival.
Longitudinal trends in climate drive flowering time clines in North American Arabidopsis thaliana
Authors: Samis Karen E. , Murren Courtney J. , Bossdorf Oliver , Donohue Kathleen , Fenster Charles B. , Malmberg Russell L. , Purugganan Michael D. , Stinchcombe John R.
Published: May 2012

Introduced species frequently show geographic differentiation, and when differentiation mirrors the ancestral range, it is often taken as evidence of adaptive evolution. The mouse‐ear cress (Arabidopsis thaliana) was introduced to North America from Eurasia 150–200 years ago, providing an opportunity to study parallel adaptation in a genetic model organism. Here, we test for clinal variation in flowering time using 199 North American (NA) accessions of A. thaliana, and evaluate the contributions of major flowering time genes FRI, FLC, and PHYC as well as potential ecological mechanisms underlying differentiation. We find evidence for substantial within population genetic variation in quantitative traits and flowering time, and putatively adaptive longitudinal differentiation, despite low levels of variation at FRI, FLC, and PHYC and genome‐wide reductions in population structure relative to Eurasian (EA) samples. The observed longitudinal cline in flowering time in North America is parallel to an EA cline, robust to the effects of population structure, and associated with geographic variation in winter precipitation and temperature. We detected major effects of FRI on quantitative traits associated with reproductive fitness, although the haplotype associated with higher fitness remains rare in North America. Collectively, our results suggest the evolution of parallel flowering time clines through novel genetic mechanisms.
2‐Halogeno‐1,3,2‐diselenaphospholanes with an Annelated Dicarba‐closo‐dodecaborane(12) Unit: Synthesis, Molecular Structure and Reactivity
Authors: Wrackmeyer Bernd , Klimkina Elena V. , Milius Wolfgang
Published: May 2012

Exchange reactions of 2,2‐dimethyl‐4,5‐[1,2‐dicarba‐closo‐dodecaborano(12)]‐1,3‐diselena‐2‐silacyclopentane with phosphorus trihalides PX3(X = Cl, Br, I) led to the corresponding phospholanes in high yield. The solid‐state structure of the iodide was determined by X‐ray crystallography. Treatment of the bromide withnBu3SnH afforded the parent phosphane. The reaction of the iodide with LiAlH4in [D8]toluene proceeded very slowly and mainly gave the deuterated phosphane. All products were characterised in solution by multinuclear magnetic resonance methods (1H,13C,31P and77Se NMR). Molecular gas‐phase geometries were optimised at the B3LYP/6‐311+G(d,p) level of theory, and NMR parameters were calculated.
Reshaping Rubrene by Controlled Reduction with Alkali Metals
Authors: Zabula Alexander V. , Sumner Natalie J. , Filatov Alexander S. , Spisak Sarah N. , Grigoryants Vladimir M. , Petrukhina Marina A.
Published: May 2012

Mono‐, di‐ and tetraanions of rubrene, (C42H28, Rub0), were generated by the controlled reduction of neutral polyarene with various alkali metals in the appropriate solvent. The X‐ray diffraction studies of the resulting adducts of Rub1–, Rub2– and Rub4– with alkali‐metal ions revealed the distortion of the rubrene core upon the stepwise acquisition of electrons. Coordination of the Cs+ ion and a noticeable deformation of Rub1– are observed at the first reduction step. Two types of rubrene dianions showing an essentially different conformation and coordination environment for the central tetracene core have been seen in the cesium adduct of Rub2–. Various types of supramolecular assembly between the tetrareduced rubrene anion, Rub4–, and lithium or rubidium cations have been found in the corresponding products in the solid state. The structures of rubrene anions and their aggregation with alkali‐metal ions in solution have been studied by ESR and multinuclear NMR (1H, 13C, 7Li and 133Cs) spectroscopy.
Partial systematic adaptive cluster sampling
Authors: Dryver Arthur L. , Netharn Urairat , Smith David R.
Published: May 2012

A main benefit from taking a systematic sample is the ease of implementation when field sampling. However, it is not uncommon for a researcher to sample only one primary sampling unit (PSU) but to assume that the secondary sampling units (SSUs) were selected by simple random sampling to obtain a variance estimate. To obtain an unbiased estimator of variance for conventional or adaptive systematic sampling, it is necessary to sample > 1 PSUs, and this can marginally increase cost and complicate implementation. We show that it is possible to obtain an unbiased estimate of variance if the researcher takes only a single PSU and one or more SSUs. Although this is no longer a true systematic sample, such a design retains much of the simplicity of sampling a single PSU and allows for a valid variance estimate.

This paper introduces three new sampling strategies stemming from systematic adaptive cluster sampling and the Raj estimator. The new sampling designs will be referred to as partial systematic adaptive cluster sampling. The sampling strategies are investigated in a simulation study that utilizes distance traveled as a measure of cost when comparing sampling strategies. When only a single PSU can be sampled because of cost or logistics concerns, we recommend also sampling one or more SSUs to obtain an unbiased estimate of variance. Copyright © 2012 John Wiley & Sons, Ltd.
‘I Know I Can Help You’: Parental Self‐efficacy Predicts Adolescent Outcomes in Family‐based Therapy for Eating Disorders
Authors: Robinson Adèle Lafrance , Strahan Erin , Girz Laura , Wilson Anne , Boachie Ahmed
Published: May 2012

Family‐based therapy is regarded as best practice for the treatment of eating disorders in adolescents. In family‐based therapy, parents play a vital role in bringing their child or adolescent to health; however, little is known about the parent‐related mechanisms of change throughout treatment. The present study examines parent and adolescent outcomes of family‐based therapy as well as the role of parental self‐efficacy in relation to adolescent eating disorder, depressed mood and anxiety symptoms. Forty‐nine adolescents and their parents completed a series of measures at assessment, at 3‐month post‐assessment and at 6‐month follow‐up. Results indicate that, throughout treatment, parents experienced an increase in self‐efficacy and adolescents experienced a reduction in symptoms. Maternal and paternal self‐efficacy scores also predicted adolescent outcomes throughout treatment. These results are consistent with the philosophy of the family‐based therapy model and add to the literature on possible mechanisms of change in the context of family‐based therapy. Copyright © 2012 John Wiley & Sons, Ltd and Eating Disorders Association.
DO HEALTHCARE REPORT CARDS CAUSE PROVIDERS TO SELECT PATIENTS AND RAISE QUALITY OF CARE?
Authors: Chen Yijuan , Meinecke Juergen
Published: May 2012

We exploit a brief period of asymmetric information during the implementation of Pennsylvania's ‘report card’ scheme for coronary artery bypass graft surgery to test for improvements in quality of care and selection of patients by healthcare providers. During the first 3 years of the 1990s, providers in Pennsylvania had an incentive to bias report cards by selecting patients strategically, with patients having no access to the report cards. This dichotomy enables us to separate providers' selection of patients from patients' selection of providers.

Using data from the Nationwide Inpatient Sample, we estimate a nonlinear difference‐in‐differences model and derive asymptotic standard errors. The mortality rate for bypass patient decreases by only 0.05 percentage points because of the report cards, which we interpret as evidence that quality of bypass surgery did not improve (at least in the short‐term) nor did patient selection by providers occur. Our timing, estimation, and asymptotics are readily applicable to many other report card schemes. Copyright © 2012 John Wiley & Sons, Ltd.
DOES DONOR ASSISTANCE FOR HIV RESPOND TO MEDIA PRESSURE?
Authors: Carmignani Fabrizio , Lordan Grace , Tang Kam Ki
Published: May 2012

HIV/AIDS is a heavily mediatised disease. In this article, we test whether media attention is affecting donors' disbursement of aid for HIV to African countries. We use information available on the number of articles and press documents on HIV issues and other health concerns published in donor countries to construct a proxy of media coverage. This proxy is then included as an explanatory variable in a regression of aid for HIV to Africa. After controlling for several donor characteristics, we find that greater media coverage increases aid disbursement. This may be good news for the HIV campaign but may result in displacement effects to the extent that other diseases that cause greater mortality and morbidity receive less media coverage than HIV and thus less health aid. Copyright © 2012 John Wiley & Sons, Ltd.
B cell homeostasis in chronic hepatitis C virus–related mixed cryoglobulinemia is maintained through naïve B cell apoptosis
Authors: Holz Lauren E. , Yoon Joo Chun , Raghuraman Sukanya , Moir Susan , Sneller Michael C. , Rehermann Barbara
Published: May 2012

Mixed cryoglobulinemia (MC) is the most common extrahepatic manifestation of chronic hepatitis C virus (HCV) infection. Although the formation of inflammation-triggering immune complexes is driven by clonal expansions of autoreactive B cells, we found total B cell numbers paradoxically reduced in HCV-infected patients with MC. HCV patients with MC (n = 17) also displayed a reduced number and a reduced frequency of naïve B cells compared with HCV-infected patients without MC (n = 19), hepatitis B virus–infected patients (n = 10), and uninfected controls (n = 50). This was due to an increased sensitivity of naïve B cells to apoptosis resulting in a reduction in the size of the naïve B cell subset. In addition, 4-fold expansion and skewing (lower T1/T2-ratio) of the immature B cell subset was noted in MC patients, suggesting that apoptosis of naïve B cells triggered the release of B cell precursors from bone marrow in an attempt to maintain normal B cell numbers. Following treatment of MC with the B cell–depleting antibody rituximab, the size of all B cell subsets, the T1/T2-ratio, and the cyroglobulin levels all normalized. Cryoglobulin levels correlated with

in vivo

proliferation of T2 B cells, suggesting a link between the skewing of the T1/T2 ratio and the formation of immune complexes.

Conclusion :

This study provides insight into the mechanisms maintaining B cell homeostasis in HCV-induced MC and the ability of rituximab therapy to restore normal B cell compartments.
Simple method for spectral evaluation of radiant energy emitted from far infrared heaters
Authors: Ogasawara Nagahisa , Kimura Yoshitaka
Published: May 2012

It is necessary to know the spectral emissivity of a heater to ensure efficient heating. This paper proposes a useful method for spectral evaluation of radiation energy emitted from far infrared heaters. The measurement device consists of one radiometer and two band‐pass filters. In order to confirm the experimental results, numerical simulations were also carried out with the spectral emissivity of the heaters and the respective spectral sensitivities of the radiometers. The results obtained by these methods show that the far infrared heater radiates high amounts of energy in the far infrared region even at high temperature. It means far infrared heaters can transmit power effectively to materials which exhibit high emissivity in the far infrared region. This method can classify a type of far remote infrared heaters with the near infrared/far infrared energy ratio. By using this data, the authors also proposed a simple identification method of spectral emissivity of far infrared heaters. This inverse method can obtain a rough value of the spectral emissivity of commercial heaters while maintaining the heating conditions. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.20396
Effects of diameter ratio of adiabatic circular cylinder and tilt angle on natural convection from a square open tilted cavity
Authors: Saha Sumon , Hussein Ahmed Kadhim , Khan Waqar Ahmed , Mohammed H.A. , Pakdee Watit , Hasanpour Arman
Published: May 2012

A numerical analysis is carried out to study the performance of natural convection inside a square open tilted cavity filled with air. An adiabatic circular solid cylinder is placed at the center of the cavity and the sidewall in front of the breathing space is heated by a constant heat flux. The top and bottom walls are kept at the ambient constant temperature. Two‐dimensional forms of Navier–Stokes equations along with the energy equations are solved using the Galerkin finite element method. Results are obtained for a range of Grashof numbers from 103 to 106 at Pr = 0.71 while the tilt angle varies from 0 to 45° and the diameter ratio of the cylinder is considered to be 0.2, 0.3, and 0.4 with constant physical properties. The parametric studies for a wide range of cylinder diameter ratios and cavity tilt angles show significant features of the present problem in terms of stream functions and temperature profiles. The computational results indicate that the heat transfer coefficient is strongly influenced by the above governing parameters. It is also found that the average Nusselt number decreases when the diameter ratio increases. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21001
Role of Prandtl number in the interaction phenomenon of surface radiation with an opposing mixed convection within a differential heated cavity
Authors: Mahapatra S.K. , Samantaray S. , Sarkar A.
Published: May 2012

A numerical analysis has been done for opposing mixed convection resulting due to wall movement and buoyancy induced by a clockwise fluid motion in a differentially heated cavity. The effect of Prandtl number (Pr) and wall surface emissivity (ϵ) has been investigated for different values of Richardson number. The net radiation method has been employed to simulate the effect of surface radiation. The energy equation along with its nonlinear boundary condition is treated with the Newton‐Raphson scheme. As momentum and energy equations are coupled with each other through their source terms, an iterative solution procedure is employed. A vorticity‐stream function formulation of the momentum equation has been adopted and solved by using an underrelaxation parameter of 0.45. The effect of Prandtl number with respect to the transformation of a multi‐cellular structure of streamline into a unicellular structure has been analyzed. For the same Richardson number (Ri) with an increase in Prandtl number, the flow and heat transfer phenomena changes from a buoyancy‐induced dominated flow to a shear‐induced dominated flow, which leads to some exciting results with respect to wall movement as well. Furthermore, the role of surface radiation in this respect has been emphasized. Nusselt number variation with the Prandtl number and surface emissivity has also been presented. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21003
Numerical study of ferrofluid flow and heat transfer in the presence of a non‐uniform magnetic field in rectangular microchannels
Authors: Mohammadpourfard M.
Published: May 2012

This paper presents a numerical investigation of the hydro‐thermal behavior of a ferrofluid in rectangular minichannels in the presence of a non‐uniform magnetic field using a two‐phase mixture model and control volume technique. Effects of increasing the diameter of nanoparticles, and channel aspect ratio have also been studied. It is concluded that the magnetic field with a negative gradient increases the Nusselt number and the rate of this increment depends on the channel aspect ratio. © 2012 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21004