bluuebunny/crossref_metadata_2025 huggingface dataset:
Scale morphology and flexibility in the shortfin mako Isurus oxyrinchus and the blacktip shark Carcharhinus limbatus
Authors: Motta Philip , Habegger Maria Laura , Lang Amy , Hueter Robert , Davis Jessica
Published: June 2012

We quantified placoid scale morphology and flexibility in the shortfin mako Isurus oxyrinchus and the blacktip shark Carcharhinus limbatus. The shortfin mako shark has shorter scales than the blacktip shark. The majority of the shortfin mako shark scales have three longitudinal riblets with narrow spacing and shallow grooves. In comparison, the blacktip shark scales have five to seven longitudinal riblets with wider spacing and deeper grooves. Manual manipulation of the scales at 16 regions on the body and fins revealed a range of scale flexibility, from regions of nonerectable scales such as on the leading edge of the fins to highly erectable scales along the flank of the shortfin mako shark body. The flank scales of the shortfin mako shark can be erected to a greater angle than the flank scales of the blacktip shark. The shortfin mako shark has a region of highly flexible scales on the lateral flank that can be erected to at least 50°. The scales of the two species are anchored in the stratum laxum of the dermis. The attachment fibers of the scales in both species appear to be almost exclusively collagen, with elastin fibers visible in the stratum laxum of both species. The most erectable scales of the shortfin mako shark have long crowns and relatively short bases that are wider than long. The combination of a long crown length to short base length facilitates pivoting of the scales. Erection of flank scales and resulting drag reduction is hypothesized to be passively driven by localized flow patterns over the skin. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.
Scaling and adaptations of incisors and cheek teeth in caviomorph rodents (Rodentia, Hystricognathi)
Authors: Becerra Federico , Vassallo Aldo I. , Echeverría Alejandra I. , Casinos Adrià
Published: June 2012

The South American hystricognath rodents are one of the most diverse mammalian clades considering their occupied habitats, locomotor modes and body sizes. This might have been partly evolved by diversification of their masticatory apparatus' structure and its ecological commitment, for example, chisel‐tooth digging. In this phylogeny‐based comparative study, we test the relationship between ecological behavior and mechanical features of their incisors and molariforms. In 33 species of nine families of caviomorph rodents, we analyze incisor attributes related to structural stress resistance and molar features related with grinding capacity, for example, second moment of inertia and enamel index (EI) (enamel band length/occlusal surface area), respectively. Most of these variables scaled isometrically to body mass, with a strong phylogenetic effect. A principal component analysis discrimination on the EI clustered the species according to their geographic distribution. We presume that selective pressures in Andean–Patagonian regions, on particular feeding habits and chisel‐tooth digging behaviors, have modeled the morphological characteristics of the teeth. Subterranean/burrower ctenomyids, coruros, and plains viscachas showed the highest bending/torsion strength and anchorage values for incisors; a simplified enamel pattern in molariforms would be associated with a better grinding of the more abrasive vegetation present in more open and drier biomes. J. Morphol. 2012. © 2012 Wiley Periodicals, Inc.
Field shaping arrays: A means to address shading in high field breast MRI
Authors: Hancu Ileana , Lee Seung‐Kyun , Dixon W. Thomas , Sacolick Laura , Becerra Ricardo , Zhang Zhenghui , McKinnon Graeme , Alagappan Vijayanand
Published: June 2012

Purpose:

To develop a simple correction approach to mitigate shading in 3 Tesla (T) breast MRI.

Materials and Methods:

A slightly modified breast receive (Rx) array, which we termed field shaping array (FSA), was shown to mitigate breast shading at 3T. In this FSA, one Rx element was selectively unblocked and tuned off the Larmor frequency during the transmit (Tx) phase. The current flowing in this element during Tx created a secondary transmit field; the vector addition of this field and the one created directly by the body coil resulted in a more uniform excitation profile over the entire breast area. The receive Rx element was returned to its intended tuning during the Rx phase, ensuring unperturbed signal reception.

Results:

Using the FSA, improved Tx field uniformity, better fat suppression, increased image homogeneity and reduced power deposition was seen in all volunteers studied.

Conclusion:

A simple modification of a standard breast Rx array, converting it to a field shaping array, was shown to mitigate breast shading in all volunteers studied. J. Magn. Reson. Imaging 2012;36:865–872. © 2012 Wiley Periodicals, Inc.
Investigation of higher‐order cognitive functions during exposure to a high static magnetic field
Authors: Lepsien Jöran , Müller Karsten , von Cramon D. Yves , Möller Harald E.
Published: June 2012

Purpose:

To test for potential changes in higher‐order cognitive processes related to the exposure to a high static magnetic field.

Materials and Methods:

Twenty‐four healthy volunteers participated in two experimental sessions inside a 3 Tesla (T) magnetic resonance imaging (MRI) magnet. During one session the magnetic field was ramped down. The tasks consisted of six well‐established paradigms probing a variety of cognitive functions. Reaction times (RT) and accuracies (AC) were recorded for statistical analysis.

Results:

The overall performance was very similar in both sessions. Strong task‐specific effects (all P < 0.006) were consistent with previously published results. Direct comparisons of task‐specific effects between the two sessions (magnetic field on or off) remained insignificance for all paradigms (RT: all P > 0.196; AC: all P > 0.17; no corrections for multiple comparisons).

Conclusion:

The results did not indicate any apparent safety concerns with respect to cognitive performance in a static magnetic field of a typical whole‐body magnet. In addition, comparisons of cognitive effects from testing situations with and without exposure to high static magnetic fields can be considered valid. J. Magn. Reson. Imaging 2012;36:835–840. © 2012 Wiley Periodicals, Inc.
Differentiating combined hepatocellular and cholangiocarcinoma from mass‐forming intrahepatic cholangiocarcinoma using gadoxetic acid‐enhanced MRI
Authors: Hwang Jiyoung , Kim Young Kon , Park Min Jung , Lee Mi Hee , Kim Seong Hyun , Lee Won Jae , Rhim Hyun Chul
Published: June 2012

Purpose:

To examine the differential features of combined hepatocellular and cholangiocarcinoma (HCC‐CC) from mass‐forming intrahepatic cholangiocarcinoma (ICC) on gadoxetic acid‐enhanced MRI.

Materials and Methods:

Forty patients with pathologically proven combined HCC‐CC (n = 20) and ICCs (n = 20) who had undergone gadoxetic acid‐enhanced MRI were enrolled in this study. MR images were analyzed for the shape of lesions, hypo‐ or hyperintense areas on the T2‐weighted image (T2WI), rim enhancement during early dynamic phases, and central enhancement with hypointense rim (target appearance) on the 10‐min and 20‐min hepatobiliary phase (HBP). The significance of these findings was determined by the χ2 test.

Results:

Irregular shape and strong rim enhancement during early dynamic phases, and absence of target appearance on HBP favored combined HCC‐CCs (P < 0.05). Lobulated shape, weak peripheral rim enhancement, and the presence of complete target appearance on the 10‐min and 20‐min HBP favored ICCs (P < 0.05). However, 10 CC‐predominant type of combined HCC‐CC showed complete or partial target appearance on 10‐min HBP.

Conclusion:

The shape of tumors, degree of rim enhancement during early dynamic phases, and target appearance on HBP were valuable for differentiating between combined HCC‐CC and mass‐forming ICC on gadoxetic acid‐enhanced MRI. J. Magn. Reson. Imaging 2012;36:881–889. © 2012 Wiley Periodicals, Inc.
CPTSD is a distinct entity: Comment on Resick et al. (2012)
Authors: Herman Judith
Published: June 2012

The concept of complex posttraumatic stress disorder (CPTSD) is both conceptually and clinically useful. This distinct entity is highly prevalent, across different cultures, in survivors of prolonged, repeated trauma. Recognition of this entity as part of the spectrum of traumatic disorders would promote development of effective treatment.
A critical evaluation of the complex PTSD literature: Implications for DSM‐5
Authors: Resick Patricia A. , Bovin Michelle J. , Calloway Amber L. , Dick Alexandra M. , King Matthew W. , Mitchell Karen S. , Suvak Michael K. , Wells Stephanie Y. , Stirman Shannon Wiltsey , Wolf Erika J.
Published: June 2012

Complex posttraumatic stress disorder (CPTSD) has been proposed as a diagnosis for capturing the diverse clusters of symptoms observed in survivors of prolonged trauma that are outside the current definition of PTSD. Introducing a new diagnosis requires a high standard of evidence, including a clear definition of the disorder, reliable and valid assessment measures, support for convergent and discriminant validity, and incremental validity with respect to implications for treatment planning and outcome. In this article, the extant literature on CPTSD is reviewed within the framework of construct validity to evaluate the proposed diagnosis on these criteria. Although the efforts in support of CPTSD have brought much needed attention to limitations in the trauma literature, we conclude that available evidence does not support a new diagnostic category at this time. Some directions for future research are suggested.
Advocacy through science: Reply to comments on Resick et al. (2012)
Authors: Resick Patricia A. , Wolf Erika J. , Stirman Shannon Wiltsey , Wells Stephanie Y. , Suvak Michael K. , Mitchell Karen S. , King Matthew W. , Bovin Michelle J.
Published: June 2012

The 4 comments on the review by Resick et al. (2012) of the complex posttraumatic stress disorder (CPTSD) literature highlight important theoretical and conceptual questions about the nature and utility of CPTSD and echo the very questions that motivated the review. We discuss the points raised in the comments, particularly with respect to the definition of CPTSD, its relationship to PTSD, and treatment implications. We suggest that setting high scientific standards for CPTSD research is an optimal way to advance the conceptualization of the construct and the treatment of this population.
Association between posttraumatic stress, depression, and functional impairments in adolescents 24 months after traumatic brain injury
Authors: O'Connor Stephen S. , Zatzick Douglas F. , Wang Jin , Temkin Nancy , Koepsell Thomas D. , Jaffe Kenneth M. , Durbin Dennis , Vavilala Monica S. , Dorsch Andrea , Rivara Frederick P.
Published: June 2012

The degree to which postinjury posttraumatic stress disorder (PTSD) and/or depressive symptoms in adolescents are associated with cognitive and functional impairments at 12 and 24 months after traumatic brain injury (TBI) is not yet known. The current study used a prospective cohort design, with baseline assessment and 3‐, 12‐, and 24‐month followup, and recruited a cohort of 228 adolescents ages 14–17 years who sustained either a TBI (n = 189) or an isolated arm injury (n = 39). Linear mixed‐effects regression was used to assess differences in depressive and PTSD symptoms between TBI and arm‐injured patients and to assess the association between 3‐month PTSD and depressive symptoms and cognitive and functional outcomes. Results indicated that patients who sustained a mild TBI without intracranial hemorrhage reported significantly worse PTSD (Hedges g = 0.49, p = .01; Model R2 = .38) symptoms across time as compared to the arm injured control group. Greater levels of PTSD symptoms were associated with poorer school (η2 = .07, p = .03; Model R2 = .36) and physical (η2 = .11, p = .01; Model R2 = .23) functioning, whereas greater depressive symptoms were associated with poorer school (η2 = .06, p = .05; Model R2 = .39) functioning.
Colony connectivity of Pacific Coast double‐crested cormorants based on post‐breeding dispersal from the region's largest colony
Authors: Courtot Karen N. , Roby Daniel D. , Adkins Jessica Y. , Lyons Donald E. , King D. Tommy , Larsen R. Scott
Published: June 2012

To reduce conflicts with fish resources, other colonial waterbirds, and damage to habitats, double‐crested cormorants (Phalacrocorax auritus) are currently controlled (lethally and non‐lethally) throughout much of their range. Concerns are growing over the Pacific Coast's largest double‐crested cormorant colony at East Sand Island (ESI), Oregon near the mouth of the Columbia River, where cormorants forage on juvenile salmonids, many of which are listed under the United States Endangered Species Act. Management of this colony is currently under consideration and may call for a redistribution of a portion of this colony numbering more than 12,000 breeding pairs in 2009. We investigated regional and site‐specific connectivity of ESI cormorants using satellite‐telemetry to track post‐breeding dispersal. Cormorants dispersed widely west of the Cascade‐Sierra Nevada Mountains from British Columbia, Canada to northern Mexico. Tracking data demonstrated direct connectivity between the double‐crested cormorant colony at ESI and nesting sites throughout the dispersal area. Results of this study indicate that some cormorants from ESI could disperse to prospect for nesting sites throughout much of the western portion of the range of the Western Population; however, regional variation in connectivity with the ESI population, distance from ESI, and site‐specific nesting history will likely result in variable prospecting rates among regions and sub‐regions. Management efforts aimed at redistributing ESI cormorants across western North America (e.g., social attraction or dissuasion techniques) might be best allocated to areas or sites known to be used by tagged cormorants, particularly those sites with an established nesting history. © 2012 The Wildlife Society.
The Level of Concern aboutFengShui in House Purchasing: The Impacts of Self‐efficacy, Superstition, and theBigFive Personality Traits
Authors: Peng Yu‐Shu , Hsiung Hsin‐Hua , Chen Ke‐Hung
Published: June 2012

FengShui has significant and widespread influences inChinese society, but modernChinese people hold different perspectives on its validity. By using house purchasing as the research context, this study proposes a theoretical model that examines the psychological process linking theBigFive personality traits, personal beliefs (superstition and self‐efficacy), and the concern ofFengShui. This model was tested in a sample of 246 residents living in the capital ofTaiwan. Empirical results reveal that superstition has a positive influence on an individual's level of concern aboutFengShui, whereas self‐efficacy has a negative influence. The results also show that three personality traits are related to superstition, and four personality traits are related to self‐efficacy. In other words, personality traits can indirectly influence an individual's level of concern aboutFengShui through the mediation effects of superstition and self‐efficacy.
Advanced Luminescent Materials Based on Organoboron Polymers
Authors: Tanaka Kazuo , Chujo Yoshiki
Published: June 2012

Our work on the characteristics of organoboron‐containing polymers is reviewed. The electronic interaction and correlation involving organoboron complexes are responsible for the optical and electric properties of the polymers. To understand the origins of these properties and apply them to the next generation of new materials, we have gathered not only fundamental knowledge on the electronic states and behaviors of each organoboron complex in the polymers but also on the functions of the polymers in devices. In this article, we introduce our findings obtained from a series of studies on polymers involving cyclodiborazane, quinolate, diketonate, dipyrromethene, pyrazabole, and carborane complexes. In particular, there is a focus on results from recent work.
Energy and entropy of crystals, melts and glasses or what is wrong in Kauzmann's paradox?
Authors: Hoffmann H.‐J.
Published: June 2012

In order to understand the thermodynamic properties of solids and melts one has to consider simultaneously their entropy and energy as a function of temperature. Therefore, the molar entropy, S, and enthalpy (energy), H, of crystals, glasses and melts of the same one‐component systems have been suitably depicted including the transformation from the melt into a solid, i. e. a glass or crystal. S and H of glasses correspond to a simple continuation of these functions from the molten state to lower temperatures. Since crystallisation occurs spontaneously such a process necessarily produces entropy causing the temperature to increase. Thus, the glassy and the crystalline state are not connected by an isothermal process, which is in contrast to the assumption in the classical nucleation and crystallisation theory as well as in the arguments causing Kauzmann's paradox. For the temperature T → 0K the enthalpy and entropy of the glass are larger by ΔH0 and ΔS0 as compared to the stable crystal. The calculations are illustrated using experimental data for quartz and silica glass from P. Richet, Y. Bottinga, L. Deniélou, J. P. Petitet and C. Téqui.
The point‐wise convergence of general rational Fourier series
Authors: Tan Lihui , Zhou Chaoying
Published: June 2012

Let be a sequence included in a compact subset of the unit disk ; we consider the rational Fourier series that are obtained by orthogonalization of the Blaschke product sequence {B0(eix) = 1,B1(eix), ⋯  ,Bn(eix), ⋯  }, where
urn:x-wiley:01704214:media:mma2636:mma2636-math-0004

In order to study the point‐wise convergence of this rational Fourier series, let the partial sums of f ∈ L1[ − π,π] be defined as
urn:x-wiley:01704214:media:mma2636:mma2636-math-0005

where for . In this paper, we will show that the conditions for the point‐wise convergence of f(x) − Sn(f)(x) is the same as that of the Fourier series. More precisely, one is the Dirichlet–Dini criterion, and the other is the Jordan test. Copyright © 2012 John Wiley & Sons, Ltd.
Geodesic finite elements on simplicial grids
Authors: Sander Oliver
Published: June 2012

We introduce geodesic finite elements as a conforming way to discretize partial differential equations for functionsv: Ω → M, where Ω is an open subset ofandMis a Riemannian manifold. These geodesic finite elements naturally generalize standard first‐order finite elements for Euclidean spaces. They also generalize the geodesic finite elements proposed ford = 1 in a previous publication of the author. Our formulation is equivariant under isometries ofMand, hence, preserves objectivity of continuous problem formulations. We concentrate on partial differential equations that can be formulated as minimization problems. Discretization leads to algebraic minimization problems on product manifoldsMn. These can be solved efficiently using a Riemannian trust‐region method. We propose a monotone multigrid method to solve the constrained inner problems with linear multigrid speed. As an example, we numerically compute harmonic maps from a domain intoS2. Copyright © 2012 John Wiley & Sons, Ltd.
Surface properties and thermal stability of a novel low‐surface‐energy polybenzoxazine/clay nanocomposites
Authors: Dong Huijie , Xin Zhong , Lu Xin , Qu Li
Published: June 2012

A novel type of polybenzoxazine (PB‐m)/clay nanocomposites were prepared from 2‐bis (3‐methyl‐3,4‐dihydro‐2H‐1,3‐benzoxazinyl) propane (B‐m) and di‐methyl, di‐octadecyl ammonium chloride (DODMAC)‐modified clay. Surface properties and thermal stability of the PB‐m/clay nanocomposites were characterized by contact angle measurement and thermogravimetry (TGA), respectively. It was found that the PB‐m/clay nanocomposites possess the lowest surface free energy (15.27 mJ/m2) after 8 h curing at 210°C, which is even lower than that of poly (tetrafluoroethylene) (21.0 mJ/m2), and the presence of the clay in the B‐m PB‐m matrix enhances the stability of the surface energy at 210°C. FTIR results show that the intercalated structures of PB‐m/clay nanocomposites have no influence on the hydrogen‐bonding network of the PB‐m during curing. Combining with the results of atomic force microscope, it can be concluded that the stability of surface energies of the PB‐m/clay nanocomposites is mainly affected by the migration and masking of clay. Also, TGA results show that the addition of clay improves the thermal stability of PB‐m. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Effect of solution pH on crack initiation and propagation in glass‐polyester pipes subjected to impact
Authors: Stamenović M. , Putić S. , Medjo B. , Rakin M. , Zrilić M.
Published: June 2012

The objective of this study was the determination of the influence of alkaline and acidic solutions on the impact properties of glass‐polyester composite pipes. First, the impact test was performed on virgin samples (without the influence of any liquid) to obtain knowledge about the original material properties. Subsequently, the specimens were soaked in water and in alkaline and acidic solutions: sodium hydroxide, ammonium hydroxide, phosphoric acid, and nitric acid. The specimens were left in each liquid for 3, 10, 30, and 60 days at room temperature. The impact toughness and the crack initiation and propagation energies were recorded for all samples. A comparison of the results was made based on the pH values of the aggressive media, as well as based on the original impact properties and number of days of treatment. This way, the service life of pipes for transport of theexamined solutions could be predicted. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Effect of maleic anhydride grafted polypropylene compatibilizer on the morphology and properties of polypropylene/multiwalled carbon nanotube composite
Authors: Ezat G. S. , Kelly A. L. , Mitchell S. C. , Youseffi M. , Coates P. D.
Published: June 2012

The effect of maleic anhydride grafted polypropylene (MA‐g‐PP) compatibilizer on the mechanical and electrical properties of a polypropylene‐carbon nanotube composite is presented. Commercially available grades of polypropylene homopolymer (PP) and multiwalled CNT (MCNT) were used to prepare composites (PP/MCNT) by melt compounding. The effects of maleic anhydride graft level and loading on material properties were investigated. The addition of MCNT without compatibilizer enhanced the mechanical properties of PP, whereas addition of both grades of MA‐g‐PP alone had a detrimental effect. When MA‐g‐PP was added as a compatiblizer to the PP/MCNT composite, flexural and tensile moduli increased, indicating that enhanced levels of MCNT dispersion within PP had been achieved. Strength of the nanocomposite decreased with the addition of both grades of MA‐g‐PP, possibly due to the deterioration of the mechanical properties of the polymer in the presence of lower molecular weight MA‐g‐PP. Electrical resistivity improved with both grades of MA‐g‐PP, with higher maleic anhydride graft levels having the most significant effect. Scanning electron microscopy analysis confirmed that the optimum state of dispersion was for the nanocomposite prepared with MA‐g‐PP with highest grafting level. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Investigation of the nanoscale mechanical properties of carbon fiber/epoxy resin interphase. I. analysis of fiber‐stiffening effect during the nanoindentation process based on numerical simulation
Authors: Li Yanxia , Li Min , Gu Yizhuo , Zhang Zuoguang , Guan Peiqiang
Published: June 2012

The interphase in fiber reinforced polymer composites is a narrow region around the fiber with the thickness in nanoscale, and its properties have a significant effect on the composite mechanical properties. Nanoindentation method was widely accepted for the measurement of the interphase properites. Different from the homogenous material, the modulus diffence between fiber and matrix is very obvious, it is difficult to get the intrinsic properties of the interphase just depending on the experimental data due to the fiber‐stiffening effect. A numerical method is developed to simulate the nanoindentation process, to understand the fiber‐stiffening effect during the nanoindentation process in the carbon fiber/epoxy composites. The predicted results reveal that the fiber impacts the indentation response in the vicinity region of the fiber. When the indent contacts the fiber, there will be a mutation in the load–displacement curve, and the fiber‐stiffening effect is obvious, which is less affected by the thickness and modulus of the interphase and the resin matrix modulus. If the interphase thickness is smaller than the distance of indent contacting the fiber, it is nearly impossible to get the intrinsic modulus of the interphase due to the effect of fiber. On the other hand, if the interphase thickness is larger than that, in the near region about 100 nm away the indent contacting the fiber, the indentation response can reflect the difference of the interphase modulus. The gradient of the curve, that is, the indentation force varying with the distance from the fiber surface, decreases with the increase in the interphase modulus. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
An Inkblot for the Implicit Assessment of Personality: The Semantic Misattribution Procedure
Authors: Sava Florin A. , MaricuΤoiu LaurenΤiu P. , Rusu Silvia , Macsinga Irina , Vîrgă Delia , Cheng Clara Michelle , Payne B. Keith
Published: June 2012

Misattributions people make about their own reaction to ambiguous stimuli can be used to measure personality self–concepts implicitly. On the basis of a semantic misattribution priming paradigm [semantic misattribution procedure (SMP)], we assessed the implicit personality self–concept related to three dimensions included in the Big–Five model: conscientiousness, neuroticism, and extraversion. Across three studies (N1 = 98, N2 = 140, and N3 = 135), the SMP was robustly related, in the expected direction, to individual differences in self–reported personality questionnaires and managed to predict both self–reported and objectively measured behaviours. The main advantage of SMP over classical explicit measures of personality is its higher resistance to social desirability tendencies, although its psychometric properties are somewhat lower than those pertaining to explicit measures of personality. Finally, comparisons of our results with studies that used other implicit measures of personality self–concept indicate that the SMP has higher criterion validity. Copyright © 2012 John Wiley & Sons, Ltd.
Synthesis of novel high oil‐absorption resins of poly(methyl methacrylate–butyl methacrylate) by surface‐initiated atom transfer radical polymerization using activators regenerated by electron transfer for efficient removal of oil
Authors: Ji Naiyi , Chen Hou , Zong Guangxi , Wang Dongju
Published: June 2012

Oil‐absorption resins are considered one of the effective materials to separate organic chemical compounds from oily water. In this work, well‐defined high oil‐absorption resins of poly(methyl methacrylate–butyl methacrylate) grafted onto silica gel were prepared by surface‐initiated atom transfer radical polymerization using activators regenerated by electron transfer mediated by FeCl3/iminodiacetic acid. The grafted polymers were grown in a controlled manner. By considering the effect of different polymerization conditions, we prepared novel high oil‐absorption resins. The chemical structures of the resins were determined by Fourier transform IR spectroscopy. SEM and TGA were also used to characterize the resins. It was found that the resins had good heat‐resistant quality, higher oil absorbency and better oil retention and regeneration properties. The resins can absorb 31.2 g g−1 for tricholoromethane and 23.3 g g−1 for toluene. Copyright © 2012 Society of Chemical Industry
Immobilization of catalases on amidoxime polyacrylonitrile nanofibrous membranes
Authors: Feng Quan , Wang Qingqing , Tang Bin , Wei Anfang , Wang Xueqian , Wei Qufu , Huang Fenglin , Cai Yibing , Hou Dayin , Bi Songmei
Published: June 2012

Amidoxime polyacrylonitrile (AOPAN) nanofibrous membranes were generated by the reaction between electrospun polyacrylonitrile nanofibrous membranes and hydroxylamine hydrochloride. AOPAN nanofibrous membranes were further modified by Fe(III) chelation for immobilizing catalases with coordination bonds. The surface morphologies of the nanofibrous membranes and immobilized catalases were observed by field emission scanning electron microscopy. Chelation of Fe(III) onto AOPAN nanofibrous membranes was studied by the Langmuir isothermal adsorption model. It was found that the maximum amount of coordinated Fe(III) (qm) was 4.5045 mmol g−1 (dry nanofibrous membranes) and the binding constant (Kl) was 0.0698 L mmol−1. The amounts of immobilized enzymes were determined by the method of Bradford. Kinetic parameters were analyzed for both immobilized and free catalases. The value of Vmax (7122.6 µmol mg−1 min−1) for the immobilized catalases was smaller than that for the free catalases (9203.2 µmol mg−1 min−1), and the Km for the immobilized catalases was larger. The immobilized catalases showed better resistance to pH and temperature change than the free catalases, and the storage stability of immobilized catalases was higher than that of free catalases. As for reusability, the immobilized catalases retained 71% of their activity after eight repeated uses. © 2012 Society of Chemical Industry
Photodegradation of azo‐dyes in aqueous solution by polyacrylonitrile nanofiber mat‐supported metalloporphyrins
Authors: Shao Linjun , Xing Guiying , Lv Weixi , Yu Huijun , Qiu Mingxi , Zhang Xian‐Man , Qi Chenze
Published: June 2012

Electrospinning has been employed to fabricate uniform polyacrylonitrile and polyacrylonitrile copolymer nanofiber mats supporting metalloporphyrins (MTPP; M: Zn(II), Cu(II), Ni(II), Co(II), Fe(III) and Pd(II); TPP: meso‐tetraphenylporphyrin). The nanofiber mat‐supported metalloporphyrins are shown as efficient photocatalysts for the degradation of various azo‐dyes in aqueous solutions under visible light irradiation. The effect of transition metals on azo‐dye photodegradation has been examined. The nanofiber mat‐supported copper–porphyrin and iron–porphyrin complexes are among the most effective photocatalysts for azo‐dye degradation. Immobilization of the metalloporphyrins onto the nanofiber mats greatly facilitates the recovery and reuse of the expensive and toxic photocatalysts. Most interestingly, there are no significant degradations of the photocatalytic activities of the recycled photocatalysts. © 2012 Society of Chemical Industry
Wide bandgap Cu(In,Ga)Se2 solar cells with improved energy conversion efficiency
Authors: Contreras Miguel A. , Mansfield Lorelle M. , Egaas Brian , Li Jian , Romero Manuel , Noufi Rommel , Rudiger‐Voigt Eveline , Mannstadt Wolfgang
Published: June 2012

We report on improvements to the energy conversion efficiency of wide bandgap (Eg > 1.2 eV) solar cells on the basis of CuIn1−xGaxSe2. Historically, attaining high efficiency (>16%) from these types of compound semiconductor thin films has been difficult. Nevertheless, by using (a) the alkaline‐containing high‐temperature EtaMax glass substrates from Schott AG, (b) elevated substrate temperatures of 600–650 °C, and (c) high vacuum evaporation from elemental sources following National Renewable Energy Laboratory's three‐stage process, we have been able to improve the performance of wider bandgap solar cells with 1.2 < Eg < 1.45 eV. The current density–voltage (J–V) data we present includes efficiencies >18% for absorber bandgaps of ~1.30 eV and efficiencies of ~16% for bandgaps up to ~1.45 eV. In comparing J–V parameters in similar materials, we establish gains in the open‐circuit voltage and, to a lesser degree, the fill factor value, as the reason for the improved performance. The higher voltages seen in these wide gap materials grown at high substrate temperatures are due to reduced recombination. We establish the existence of random and discrete grains within the CIGS absorbers that yield limited or no generation/collection of minority carriers. We also show that interfacial recombination is the main mechanism limiting additional enhancements to open‐circuit voltage and therefore performance. Solar cell results, absorber materials characterization, and experimental details and discussion are presented. Copyright © 2012 John Wiley & Sons, Ltd.
Fabrication of grid type dye sensitized solar modules with 7% conversion efficiency by utilizing commercially available materials
Authors: Wei Tzu‐Chien , Lan Jo‐Lin , Wan Chi‐Chao , Hsu Wen‐Chi , Chang Ya‐Huei
Published: June 2012

A process to fabricate a parallel connection dye‐sensitized solar cell (DSSC) module has been developed using commercially available materials and screen printed silver grid. The process is not only simple but also easy to manipulate and therefore facilitates researchers in evaluating new materials in a module platform. By changing the design of the silver grid pattern, it was found that the performance of DSSC modules can be controlled. With the silver grid, DSSC modules have shown that a 7% conversion efficiency can be reached. Modules fabricated by this process, but with a non‐volatile electrolyte system, passed a 60 °C, 1000 h thermal aging test. Copyright © 2012 John Wiley & Sons, Ltd.
Ag‐doped TiO2 enhanced photocatalytic oxidation of 1,2‐cyclohexanediol
Authors: Abdel‐Wahab Aboel‐Magd A. , Mohamed Omima S. , Ahmed Saleh A. , Mostafa Mostafa F.
Published: June 2012

The superiority of silver‐doped titania for photocatalytic oxidation (PCO) of organic compounds inspired us to investigate PCO of 1,2‐cyclohexanediol. Ag/TiO2 was prepared, characterized (nanosize 19–24 nm) and used for oxidation of 1,2‐cyclohexanediol (1) in acetonitrile. The photolysate was analyzed using GC and GC/MS techniques. The PCO products are 2‐hydroxylcyclohexanone (2), 1,2‐cyclohexandione (3), 2‐cyclohexenone(4), cyclohexanone (5), and adipic acid (6).The formation of electron–hole pair at the surface of the catalyst followed by oxidation reactions was the suggested mechanism. Kinetic studies revealed first‐order mechanism for PCO of 1 and rate constant (k) = −0.145 h–1. Copyright © 2012 John Wiley & Sons, Ltd.
Highly Skilled Migration: What Differentiates the ‘Brains’ Who Are Drained from Those Who Return in the Case of Greece?
Authors: Labrianidis Lois , Vogiatzis Nikos
Published: June 2012

The migration of highly educated population (brain drain) poses extremely significant impacts on origin countries' development, especially in cases in which, owing to their economic and social structures, these countries cannot promote the efficient allocation of their professionals. At the same time, the decision of those migrants to return home or remain abroad is affected by several factors. This paper aims to analyse this phenomenon by using primary data collected from Greece. Our findings indicate that it is not reasonable to expect that a large share of these people is likely to return, especially given the ongoing economic and social crises that further exacerbate the observed mismatch between supply and demand for a highly educated workforce in the country. These empirical results can assist the formulation of specific policy measures in order to reap the benefits of those individuals' presence abroad, which can undoubtedly enhance the developmental prospects of European countries. This study constitutes the first one on brain drain from Greece, while it is also the first study to compare highly skilled migrants who still work abroad to those who have returned. Copyright © 2012 John Wiley & Sons, Ltd.
The choice of the exchange‐correlation functional for the determination of the jahn–teller parameters by the density functional theory
Authors: Andjelković Ljubica , Gruden‐Pavlović Maja , Daul Claude , Zlatar Matija
Published: June 2012

The Jahn–Teller (JT) parameters for small, aromatic, organic radicals, CnHn (n = 4–7), bis(cyclopentadienyl)cobalt(II) (cobaltocene), a sodium cluster (Na3), a silver cluster (Ag3), the hexaflurocuprate(II) ion ([CuF6]4−), and tris(acetylacetonato)manganese(III) ([Mn(acac)3]) have been evaluated by the means of the multideterminantal density functional theory using the most common approximations, to clarify which type of exchange‐correlation functional should be used in analysis of the JT effect. The results are compared with available experimental and theoretical data. The choice of the functional strongly depends on the chemical system at hand, but to obtain fast and qualitatively reliable results, the local density approximation may be taken as satisfactory, regardless of the diversity of the systems prone to a JT distortion. © 2012 Wiley Periodicals, Inc.
Docking between natural peroxides and heme group by parametric method 6
Authors: Leite Franco Henrique Andrade , de Mesquita Carneiro José Walkimar , de Araujo Martha Teixeira , Comar Moacyr , Taranto Alex Gutterres
Published: June 2012

Artemisinin (Qinghaosu) is a sesquiterpene lactone with an endoperoxide function being currently used against strains of Plasmodium falciparum. These compounds are supposed to act on heme leading to reduction of the peroxide bond and production of radicals that can kill the parasite. The main goal of this study was the identification of new potential antimalarial drugs from natural sources as well as to find possible correlations between in silico parameters and experimental data. Thus, the interactions of 51 peroxides with heme were studied by molecular docking following refinement by conformational analysis and semiempirical parametric method 6. As a result, correlation between complex energy and dissociation constant (Kd) was found to be significant. The results indicate that compounds 5 and 24 are promising antimalarial agent. © 2012 Wiley Periodicals, Inc.
Proteomic analysis of salt‐responsive ubiquitin‐related proteins in rice roots
Authors: Liu Chih‐Wei , Hsu Yu‐Kai , Cheng Yu‐Hsiang , Yen Hung‐Chen , Wu Yung‐Pei , Wang Chang‐Sheng , Lai Chien‐Chen
Published: June 2012

RATIONALE

Ubiquitination of proteins plays an important role in regulating a myriad of physiological functions in plants such as xylogenesis, senescence, cell cycle control, and stress response. However, only a limited number of proteins in plants have been identified as being ubiquitinated in response to salt stress. The relationships between ubiquitination and salt‐stress responses in plants are not clear.

METHODS

Rice (Oryza sativa) seedlings from the same genetic background with various salt tolerances exposed to salt stress were studied. The proteins of roots were extracted then analyzed using western blotting against ubiquitin. Differentially expressed ubiquitinated proteins were identified by nanospray liquid chromatography/tandem mass spectrometry (nano‐LC/MS/MS) and quantified by label‐free methods based on the Exponentially Modified Protein Abundance Index (emPAI) and on the peak areas of XIC spectra derived from ubiquitinated peptides. In addition, we performed a gel‐based shotgun proteomic analysis to detect the ubiquitinated proteome that may be involved in response to salt stress.

RESULTS

The expressions of ubiquitination on pyruvate phosphate dikinase 1, heat shock protein 81–1, probable aldehyde oxidase 3, plasma membrane ATPase, cellulose synthase A catalytic subunit 4 [UDP‐forming] and cyclin‐C1‐1 were identified and compared before and after salt treatment. The functions of those ubiquitinated proteins were further discussed for defence against salt stress. In addition, a large number of ubiquitinated proteins were successfully identified as well in this study.

CONCLUSIONS

The ubiquitination of proteins affected the protective mechanisms in rice seedlings to resist the salt stress during the initial phase. The findings in the present study also demonstrate that the regulated mechanisms through protein ubiquitination are important for rice seedlings against salt stress. Copyright © 2012 John Wiley & Sons, Ltd.
Identification of the unknown transformation products derived from clarithromycin and carbamazepine using liquid chromatography/high‐resolution mass spectrometry
Authors: Calza P. , Medana C. , Padovano E. , Giancotti V. , Baiocchi C.
Published: June 2012

RATIONALE

A comprehensive study of the environmental fate of pollutants is more and more required, above all on new contaminants, i.e. pharmaceuticals. As high‐resolution mass spectrometry (HRMSn) may be a suitable analytical approach for characterization of unknown compounds, its performance was evaluated in this study.

METHODS

The analyses were carried out using liquid chromatography (LC) (electrospray ionization (ESI) in positive mode) coupled with a LTQ‐Orbitrap analyzer. High‐resolution mass spectrometry was employed to assess the evolution of the drug transformation processes over time; accurate masses of protonated molecular ions and sequential product ions were reported with an error below 5 millimass units, which guarantee the correct assignment of their molecular formula in all cases, while their MS2 and MS3 spectra showed several structurally diagnostic ions that allowed characterization of the different transformation products (TPs) and to distinguish the isobaric species.

RESULTS

The simulation of phototransformation occurring in the aquatic environment and identification of biotic and abiotic transformation products of the two pharmaceuticals were carried out in heterogeneous photocatalysis using titanium dioxide, aimed to recreate conditions similar to those found in the environmental samples. Twenty‐eight main species were identified after carbamazepine transformation and twenty‐nine for clarithromycin.

CONCLUSIONS

This study demonstrates that HRMS, combined with LC, is a technique able to play a key role in the evaluation of the environmental fate of pollutants and allows elucidation of the transformation pathways followed by the two drugs. Copyright © 2012 John Wiley & Sons, Ltd.
Observation of ion coalescence in Orbitrap Fourier transform mass spectrometry
Authors: Gorshkov Mikhail V. , Fornelli Luca , Tsybin Yury O.
Published: June 2012

RATIONALE

Similar to other mass spectrometric technologies based on ion trapping in a spatially restricted area, the performance of Orbitrap Fourier transform mass spectrometry (FTMS) is affected by the interaction between the trapped ion clouds. One of the effects associated with Coulombic interaction inside the ion trap is the ion cloud coupling, known in ion cyclotron resonance (ICR) FTMS as coalescence, or a phase‐locking phenomenon. Nevertheless, the direct observation of ion coalescence has not been reported for Orbitrap FTMS yet.

METHODS

We have performed experiments on ion coalescence with a pair of isobaric peptides in the state‐of‐the‐art hybrid linear ion trap high‐field compact Orbitrap Elite FT mass spectrometer using both standard and advanced signal processing modes.

RESULTS

For the instrument configuration employed in this work we found that ion coalescence occurs when two singly charged peptides with the mass difference of 22 mDa and molecular weight of about 1060 Da have the total abundance of at least 7.5*104 charges.

CONCLUSIONS

We experimentally demonstrate the existence of the ion coalescence phenomenon in Orbitrap FTMS for peptides for a wide range of total trapped ion population. Using the applicable modeling of the phase‐locking threshold we estimate the effect of ion coalescence on the performance of Orbitrap FTMS. Copyright © 2012 John Wiley & Sons, Ltd.
Dynamic behavior of the discrete‐time double integrator with saturated locally stabilizing linear state feedback laws
Authors: Yang Tao , Stoorvogel Anton A. , Saberi Ali
Published: June 2012

The main contribution of this paper is to completely characterize the dynamic behavior of the discrete‐time double integrator with a saturated locally stabilizing linear state feedback law. In continuous‐time setting, any linear state feedback control law that locally stabilizes the double integrator also globally stabilizes the system in the presence of actuator saturation. In discrete‐time setting, the equivalent of the double integrator does not have the same property. In this paper, we completely characterize the global behavior of saturated locally stabilizing linear state feedback laws for the discrete‐time double integrator. Copyright © 2012 John Wiley & Sons, Ltd.
Computer simulation of layer‐by‐layer sputtering at grazing low‐energy ion‐surface interactions
Authors: Umarov Farid F. , Dzhurakhalov Abdiravuf A.
Published: June 2012

The peculiarities of sputtering processes at low‐energy Ne grazing ion bombardment of Si(001), SiC(001) and Cu3Au(001) surfaces and their possible application for the surface modification have been studied by computer simulation. Sputtering yields in the primary knock‐on recoil atoms regime versus the initial energy of incident ions (0.5–5 keV) and angle of incidence (0–30°) with respect to the target surface have been calculated. It was shown that in the case of grazing ion bombardment, the layer‐by‐layer sputtering is possible, and its optimum is observed within the small angular range of the glancing angles near the threshold sputtering angle. Comparative studies of layer‐by‐layer sputtering for Si(001) and SiC(001) surfaces versus the initial energy of incident ions as well as an effective sputtering and sputtering threshold are discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Adaptive extensions of a two‐stage group sequential procedure for testing primary and secondary endpoints (I): unknown correlation between the endpoints
Authors: Tamhane Ajit C. , Wu Yi , Mehta Cyrus R.
Published: June 2012

In a previous paper we studied a two‐stage group sequential procedure (GSP) for testing primary and secondary endpoints where the primary endpoint serves as a gatekeeper for the secondary endpoint. We assumed a simple setup of a bivariate normal distribution for the two endpoints with the correlation coefficient ρ between them being either an unknown nuisance parameter or a known constant. Under the former assumption, we used the least favorable value of ρ = 1 to compute the critical boundaries of a conservative GSP. Under the latter assumption, we computed the critical boundaries of an exact GSP. However, neither assumption is very practical. The ρ = 1 assumption is too conservative resulting in loss of power, whereas the known ρ assumption is never true in practice. In this part I of a two‐part paper on adaptive extensions of this two‐stage procedure (part II deals with sample size re‐estimation), we propose an intermediate approach that uses the sample correlation coefficient r from the first‐stage data to adaptively adjust the secondary boundary after accounting for the sampling error in r via an upper confidence limit on ρ by using a method due to Berger and Boos. We show via simulation that this approach achieves 5–11% absolute secondary power gain for ρ ≤0.5. The preferred boundary combination in terms of high primary as well as secondary power is that of O'Brien and Fleming for the primary and of Pocock for the secondary. The proposed approach using this boundary combination achieves 72–84% relative secondary power gain (with respect to the exact GSP that assumes known ρ). We give a clinical trial example to illustrate the proposed procedure. Copyright © 2012 John Wiley & Sons, Ltd.