bluuebunny/crossref_metadata_2025 huggingface dataset:
Half‐Metallic Antiferromagnet as a Prospective Material for Spintronics
Authors: Hu Xiao
Published: September 2011

Spintronics is expected as the next‐generation technology based on the novel notch of spin degree of freedom of electrons. Half‐metals, a class of materials which behave as a metal in one spin direction and an insulator in the opposite spin direction, are ideal for spintronic applications. Half‐metallic antiferromagnets as a subclass of half‐metals are characterized further by totally compensated spin moments in a unit cell, and have the advantage of being able to generate fully spin‐polarized current while exhibiting zero macroscopic magnetization. Considerable efforts have been devoted to the search for this novel material, from which we may get useful insights for prospective material exploration.
Evaluation of nonconventional additives as fire retardants on polyamide 6,6: Phosphorous‐based master batch, α‐zirconium dihydrogen phosphate, and β‐cyclodextrin based nanosponges
Authors: Enescu Daniela , Alongi Jenny , Frache Alberto
Published: September 2011

The influence of new types of additives, such as halogen‐ and antimony‐free flame‐retardant master batches based on phosphorus, α‐zirconium dihydrogen phosphate, and β‐cyclodextrin nanosponges, on the flame retardancy of polyamide 6,6 (PA6,6) by means of cone calorimetry and limiting oxygen index (LOI) tests was investigated. A significant decrease of the heat release rate, depending by the type of additive used, was observed. Furthermore, with the consideration that the life safety during the fire could be improved by a decrease in the fire hazard, a decrease in the quantity of the smoke and its toxicity, depending also on the type of additive, was revealed. With regard to the LOI test, neat PA6,6 showed a slight increase in the LOI value in comparison with the PA6,6 composites. However, all of the PA6,6/composites showed a slower burning velocity and antidripping effects at oxygen concentrations corresponding to the LOI value. To understand the flame‐retardancy mechanism of these novel PA6,6 composites, we thoroughly investigated their thermal decomposition behavior and microstructure/elemental analysis by scanning electron microscopy/energy‐dispersive X‐ray spectroscopy. Furthermore, the combustion behavior of these novel PA6,6 composites was compared with that of conventional nanofillers (e.g., modified montmorillonite clay and carbon nanotubes). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Ferromagnetic versus Antiferromagnetic Exchange Interactions in Tetrathiafulvalene‐Based 3d/4f Heterobimetallic Complexes
Authors: Cosquer Goulven , Pointillart Fabrice , Le Gal Yann , Golhen Stéphane , Cador Olivier , Ouahab Lahcène
Published: September 2011

(TTF‐salphen)M compounds (TTF‐salphen2−=4,5‐bis(propylthio)tetrathiafulvalene‐N,N′‐phenylenebis(salicylideneimine) dianion; M=CuII and NiII) have been treated with Ln(hfac)3⋅2 H2O precursors (hfac−=1,1,1,5,5,5‐hexafluoroacetylacetonate anion; Ln=GdIII, TbIII, and DyIII) to elaborate unprecedented 3d/4f TTF‐based heterobimetallic complexes of formula [(TTF‐salphen)MLn(hfac)3]. All the structures of these compounds have been resolved by X‐ray diffraction on single crystals. The structures of these complexes are formed by a TTF‐salphen2− ligand coordinated to the 3d metal ions in the inert tetradentate N2O2 site. The Ln(hfac)3 fragment is coordinated to the (TTF‐salphen)M one through the two phenolate bridges. Even if the complexes are similar in both CuII and NiII families, the crystal packing is different. In the first case, dimers of TTF‐salphen2− donors constitute the organic network. In the other case, a reminiscent organic network is observed with S⋅⋅⋅S contacts. The photophysical properties of [(TTF‐salphen)CuDy(hfac)3] (3) in chloroform solution highlight the redshift of the TTF→salphen charge transfer (400 cm−1) relative to the analogue excitations in (TTF‐salphen)Cu, which attest to the stability of these structures in solution. Static magnetic measurements have allowed us to quantify the ferromagnetic interactions (J=+1.29 cm−1) between CuII and GdIII in the [(TTF‐salphen)CuGd(hfac)3] complex. Finally, an empirical method that consists of the comparisons of the magnetic properties of [(TTF‐salphen)CuTb(hfac)3] with [(TTF‐salphen)NiTb(hfac)3] and [(TTF‐salphen)CuDy(hfac)3] with [(TTF‐salphen)NiDy(hfac)3] has established that ferromagnetic interactions take place between CuII and TbIII ions, whereas unusual antiferromagnetic interactions have been identified between CuII and DyIII ions.
The Microbubble Flotation – an Energy Efficient Process for Paper Industry?
Authors: Voß Dennis , Schabel Samuel
Published: September 2011

Beim Recycling von graphischem Altpapier bilden Druckfarben einen wichtigen Anteil an den zu entfernenden Verunreinigungen. Vor allem die wasserbasierten Druckfarben stellen hier eine Herausforderung dar. Ziel dieser Untersuchung war die Entwicklung einer neuen Flotationstechnologie, die diese Druckfarben entfernen können. Es wurde untersucht, ob spezielle Schäume, die als Mikroblasen bezeichnet werden, zu nutzen sind. Die Mikroblasen wurden durch Rotation einer Scheibe in einem Gefäß mit speziellen Stromstörerstrukturen erzeugt. Dadurch wurden die optischen Eigenschaften von Prozesswässern deutlich verbessert und es konnten zwischen 60 – 90 % der enthaltenen Feststoffe abgetrennt werden.
Catalytic Membrane Reactors – Chemical Upgrading and Pollution Control
Authors: Czuprat Oliver , Jiang Heqing
Published: September 2011

This article presents an overview on oxygen permeation, oxidative activation of light hydrocarbons and splitting of various molecules (H2O, N2O, NOx) containing oxygen in a hollow fiber catalytic membrane reactor made of BaCoxFeyZrzO3–δ (BCFZ, x+y+z = 1) which is used to separate oxygen from oxygen containing gases. Innovative reactor concepts are introduced and performances for the various applications are discussed. A detailed view is also given on the thermodynamic and kinetic background with regard to the above mentioned reactions. The potentials in terms of product intensification and energy saving by usage of the BCFZ hollow fibers as reaction vessels are evaluated. However, there are still technological challenges that prevent the described processes from being practiced on commercial scale by now.
Wildfire extent and severity correlated with annual streamflow distribution and timing in the Pacific Northwest, USA (1984–2005)
Authors: Holden Zachary A. , Luce Charles H. , Crimmins Michael A. , Morgan Penelope
Published: September 2011

Climate change effects on wildfire occurrence have been attributed primarily to increases in temperatures causing earlier snowpack ablation and longer fire seasons. Variability in precipitation is also an important control on snowpack accumulation and, therefore, on timing of meltwater inputs. We evaluate the correlation of total area burned and area burned severely to snowmelt‐induced streamflow timing and total annual streamflow metrics across the Pacific Northwest region from 1984–2005. Principal component scores on total annual water year flow and date of 50th percentile flow (PC1T) in the Pacific Northwest were used as predictors of satellite‐inferred area burned and area burned severely in forested settings. Both annual area burned and burned severely are significantly correlated with mean annual flow and streamflow timing. PC1T alone explains 24% of the variability in annual area burned. Path analysis suggests that a substantial amount of the variability in annual area burned, previously attributed solely to temperature effects on melt timing, may be primarily driven by trends in precipitation and total annual streamflow. Principal component analysis scores on mean annual streamflow explain as much as 46% of the variability in annual area burned from 1984–2005. Thus, although streamflow timing may be a better single correlate of annual wildfire activity, timing is, in turn, strongly dependent on precipitation. These results suggest that recent fire activity in forests of this region are influenced more by precipitation variability than temperature‐induced shifts in snowmelt timing, with significant implications for our ability to predict wildfire activity in the future. Published 2011. This article is a U.S. Government work and is in the public domain in the USA.
Phosphite‐Mediated Synthesis of Benzimidazoles: A One‐Pot Four‐Component Approach from Nitrophenols
Authors: El Kaïm Laurent , Grimaud Laurence , Purumandla Srinivas Reddy
Published: September 2011

Benzimidazoles may be formed in high yield through the phosphite‐triggered reductive cyclization of o‐nitroaniline derivatives. This reaction was used for the one‐pot synthesis of benzimidazoles from o‐nitrophenols and isocyanides. The mechanism is discussed in relation with nitroso intermediates.
Synthesis of Perhydrofuro[2,3‐b]furans from Isopentenyl Alcohol through Carbonyl‐Ene and Wacker‐Type Reactions
Authors: Alonso Francisco , Rodríguez‐Fernández Mamen , Sánchez Daniel , Yus Miguel
Published: September 2011

A range of 2‐substituted perhydrofuro[2,3‐b]furans have been synthesized in a stereoselective manner through a sequence involving the Lewis‐acid catalyzed carbonyl‐ene reaction of a protected isopentenyl alcohol with a variety of enophiles, deprotection of the corresponding monoprotected diols, and palladium‐catalyzed intramolecular acetalization under Wacker‐type reaction conditions.
Bulk Heterojunction Solar Cells – Tuning of the HOMO and LUMO Energy Levels of Pyrrolic Squaraine Dyes (Eur. J. Org. Chem. 28/2011)
Authors: Beverina Luca , Drees Martin , Facchetti Antonio , Salamone Matteo , Ruffo Riccardo , Pagani Giorgio A.
Published: September 2011

The cover picture shows how the HOMO and LUMO energy levels of hydrazone end‐capped pyrrolic squaraine compounds for organic photovoltaic devices can be efficiently tuned by means of the substituent effect. The capability of tuning the LUMO position is of outmost importance to obtain efficient light‐induced charge transfer from the squaraine and the PC71BM acceptor. Moreover, the control of the HOMO energy enables the tuning of the device open circuit voltage. The squaraine general structure and synthetic access, along with their energy‐level diagram as a function of the substituent effect, are shown against a background of the sun aura atop the hills of the Joshua Tree desert in California. Details are discussed in the article by L. Beverina et al. on p. 5555 ff.
Free‐field rotations during earthquakes: Relevance on buildings
Authors: Castellani Alberto , Stupazzini Marco , Guidotti Roberto
Published: September 2011

Soil rotations around horizontal axes, during an earthquake, are studied through records collected by closely spaced arrays of strong motion accelerometers. The cross power spectrum of accelerations at nearby stations has been generally utilized to describe the spatial distribution of the motion. A number of cross spectra have been obtained during the training of these arrays. To take profit of these elaborations, a mathematical relation is established between the cross power spectrum and the power spectrum of the rotation.

Rotation data presented by Liu et al, concerning 52 earthquake records collected at a single station in Taiwan, are compared with rotation data computed according to our procedure. The two series of data are suitably normalized to the peak horizontal acceleration. The data are shown in function of the distance from epicentre. The same ratio, computed according to our procedure, is in good agreement with the average value of these data.

Direct measurements and the present approach have lead to evaluations of rotation higher than those predicted by mathematical investigations on the basis of the wave propagation theory, for comparable circumstances.

The relevance of this input motion for relatively tall structures is examined, with reference to the structural effects that the horizontal motion concurrently provides. Meaningful will be ranked those effects of the order of magnitude of 20% or higher than those implied by the horizontal excitation.

For understanding the relevance on building structures, the procedure has two areas of concern: 1) the coherence implicit in the cross power spectra, which depends on the interpolation process of the original records, collected in the arrays of instruments, and 2) the relative importance of the vertical to the horizontal input motion.

As to the second item, the relevance of the rotation component on structures largely depends on the relative importance of the vertical to the horizontal input motion. When the records in an area a few km from the epicenter are considered, the response spectrum of vertical motion is comparable and in some records even higher, than that of horizontal motion, over the entire range of frequencies. This has been observed as well for the 2009 earthquake event of L'Aquila, Italy, and that at the Christchurch (New Zealand) 2011. When the response spectrum of vertical motion is comparable to that of horizontal motion, the effects of rotational motions on most engineering structures can be meaningful. Copyright © 2011 John Wiley & Sons, Ltd.
Continental evaporites and the search for evidence of life on Mars
Authors: Barbieri Roberto , Stivaletta Nunzia
Published: September 2011

Continental evaporites are deposits that originate from the evaporation of saline waters in the low areas of saline lakes from all continents, except Europe, and mainly consist of chloride, sulphate and potash minerals. In recent years, the discovery on the Martian surface of hydrated salt minerals, including sulphates and chlorides, interpreted as deriving from the desiccation of preexisting large bodies of water, such as lakes, has provided further convincing evidence of liquid water activity on the surface of Mars and, consequently, it has reinforced the plausibility of finding life. Because evaporites require short‐term aqueous processes for their formation, they can trap and preserve over geologic times a biological record made up of halophilic extremophiles—such as microalgae, bacteria, and their remains—that recent research on Earth has shown to be characterized by unexpectedly high biodiversity. This record may consist of varying types of fossils, including morphological fossils, chemofossils and biominerals. As a consequence, continental evaporite environments and their saline deposits are now a primary target for the near future astrobiology missions devoted to the search for fossil Martian life. Lacustrine evaporite deposits and minerals have, therefore, been identified as primary targets for the NASA–ESA joint programme of the Mars sample return, planned for the end of the current decade. Copyright © 2011 John Wiley & Sons, Ltd.
Dynamically changing effects of corticosteroids on human hippocampal and prefrontal processing
Authors: Henckens Marloes J.A.G. , Pu Zhenwei , Hermans Erno J. , van Wingen Guido A. , Joëls Marian , Fernández Guillén
Published: September 2011

Stress has a powerful impact on memory. Corticosteroids, released in response to stress, are thought to mediate, at least in part, these effects by affecting neuronal plasticity in brain regions involved in memory formation, including the hippocampus and prefrontal cortex. Animal studies have delineated aspects of the underlying physiological mechanisms, revealing rapid, nongenomic effects facilitating synaptic plasticity, followed several hours later by a gene‐mediated suppression of this plasticity. Here, we tested the hypothesis that corticosteroids would also rapidly upregulate and slowly downregulate brain regions critical for episodic memory formation in humans. To target rapid and slow effects of corticosteroids on neural processing associated with memory formation, we investigated 18 young, healthy men who received 20 mg hydrocortisone either 30 or 180 min before a memory encoding task in a double‐blind, placebo‐controlled, counter‐balanced, crossover design. We used functional MRI to measure neural responses during these memory encoding sessions, which were separated by a month. Results revealed that corticosteroids' slow effects reduced both prefrontal and hippocampal responses, while no significant rapid actions of corticosteroids were observed. Thereby, this study provides initial evidence for dynamically changing corticosteroid effects on brain regions involved in memory formation in humans. Hum Brain Mapp, 2012. © 2011 Wiley Periodicals, Inc.
In vivo imaging of nuclear‐cytoplasmic deformation and partition during cancer cell death due to immune rejection
Authors: Amoh Yasuyuki , Hamada Yuko , Katsuoka Kensei , Hoffman Robert M.
Published: September 2011

In this report, we investigated the in vivo cell biology of cancer cells during immune rejection. The use of nestin‐driven green fluorescent protein (ND‐GFP) transgenic mice as hosts, in which nascent blood vessels express GFP, and implanted dual‐color mouse mammary tumor 060562 (MMT) cells, in which the cytoplasm expresses red fluorescent protein (RFP) and the nuclei express GFP, allowed very important novel observations of angiogenesis and subcellular death pathways during immune rejection of a tumor. Nascent blood vessels did not form in the initially‐growing mouse mammary tumor in ND‐GFP immunocompetent mice. In contrast, in ND‐GFP immunodeficient nude mice, numerous GFP‐expressing nascent blood vessels grew into the tumor. The results suggest that insufficient nascent tumor angiogenesis was important in tumor rejection. During immune rejection, the cancer cells deformed their cytoplasm and nuclei, which were readily imaged by RFP and GFP, respectively. The nuclear membrane of the cancer cells ruptured, and chromatin extruded during partition of cytoplasm and nuclei. T lymphocytes infiltrated into the initially‐growing tumor in the nestin‐GFP transgenic immunocompetent mice. The cytotoxic role of the sensitized T lymphocytes was confirmed in vitro when they were co‐cultured with MMT cells. The CD8a‐positive lymphocytes attached to the cancer cells and caused nuclear condensation, deformation, and partition from their cytoplasm, similar to what occurred in vivo. The color‐coded subcellular fluorescence‐imaging model of immune rejection of cancer cells can provide a comprehensive system for further testing of immune‐based treatment for cancer. J. Cell. Biochem. 113: 465–472, 2012. © 2011 Wiley Periodicals, Inc.
Oct‐3/4 promotes migration and invasion of glioblastoma cells
Authors: Kobayashi Kana , Takahashi Hisaaki , Inoue Akihiro , Harada Hironobu , Toshimori Shinichi , Kobayashi Yukako , Goto Katsuhiro , Sugimoto Kana , Yano Hajime , Ohnishi Takanori , Tanaka Junya
Published: September 2011

As a result of increased glioblastoma migration and invasion into normal brain parenchyma, treatment of local tumor recurrence following initial treatment in glioblastoma patients remains challenging. Recent studies have demonstrated increased Oct‐3/4 expression, a self‐renewal regulator in stem cells, in glioblastomas. However, little is known regarding the influence of Oct‐3/4 in glioblastoma cell invasiveness. The present study established Oct‐3/4‐overexpressing glioblastoma cells, which were prepared from human glioblastoma patients, to assess migration, invasion, and mRNA expression profiles of integrins and matrix metalloproteinases (MMPs). Compared with control cells, Oct‐3/4 expressing‐glioblastoma cells exhibited increased migration and invasion in wound healing and Matrigel invasion assays. Oct‐3/4 overexpression resulted in upregulated FAK and c‐Src expression, which mediate integrin signals. Vinculin accumulated along the leading edges of Oct‐3/4 expressing‐glioblastoma cells and associated with membrane ruffles during cell migration. Oct‐3/4 expressing‐cells exhibited increased MMP‐13 mRNA expression and MMP‐13 knockdown by shRNA suppressed cell invasion into Matrigel and organotypic brain slices. These results suggested that Oct‐3/4 enhanced degradation of surrounding extracellular matrix by increasing MMP‐13 expression and altering integrin signaling. Therefore, Oct‐3/4 might contribute to tumor promoting activity in glioblastomas. J. Cell. Biochem. 113: 508–517, 2012. © 2011 Wiley Periodicals, Inc.
A sequence‐based computational model for the prediction of the solvent accessible surface area for α‐helix and β‐barrel transmembrane residues
Authors: Wang Chengqi , Xi Lili , Li Shuyan , Liu Huanxiang , Yao Xiaojun
Published: September 2011

Predicting the solvent accessible surface area (ASA) of transmembrane (TM) residues is of great importance for experimental researchers to elucidate diverse physiological processes. TM residues fall into two major structural classes (α‐helix membrane protein and β‐barrel membrane protein). The reported solvent ASA prediction models were developed for these two types of TM residues respectively. However, this prevents the general use of these methods because one cannot determine which model is suitable for a given TM residue without information of its type. To conquer this limitation, we developed a new computational model that can be used for predicting the ASA of both TM α‐helix and β‐barrel residues. The model was developed from 78 α‐helix membrane protein chains and 24 β‐barrel membrane protein. Its prediction ability was evaluated by cross validation method and its prediction result on an independent test set of 20 membrane protein chains. The results show that our model performs well for both types of TM residues and outperforms other prediction model which was developed for the specific type of TM residues. The prediction results also proved that the random forest model incorporating conservation score is an effective sequence‐based computational approach for predicting the solvent ASA of TM residues. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011
Initiation of BMP2 signaling in domains on the plasma membrane
Authors: Bonor Jeremy , Adams Elizabeth L. , Bragdon Beth , Moseychuk Oleksandra , Czymmek Kirk J. , Nohe Anja
Published: September 2011

Bone morphogenetic protein 2 (BMP2) is a potent growth factor crucial for cell fate determination. It directs the differentiation of mesenchymal stem cells into osteoblasts, chondrocytes, adipocytes, and myocytes. Initiation of BMP2 signaling pathways occurs at the cell surface through type I and type II serine/threonine kinases housed in specific membrane domains such as caveolae enriched in the caveolin‐1 beta isoform (CAV1β, caveolae) and clathrin‐coated pits (CCPs). In order for BMP2 to initiate Smad signaling it must bind to its receptors on the plasma membrane resulting in the phosphorylation of the BMP type Ia receptor (BMPRIa) followed by activation of Smad signaling. The current model suggests that the canonical BMP signaling pathway, Smad, occurs in CCPs. However, several recent studies suggested Smad signaling may occur outside of CCPs. Here, we determined; (i) The location of BMP2 binding to receptors localized in caveolae, CCPs, or outside of these domains using AFM and confocal microscopy. (ii) The location of phosphorylation of BMPRIa on the plasma membrane using membrane fractionation, and (iii) the effect of down regulation of caveolae on Smad signaling. Our data indicate that BMP2 binds with highest force to BMP receptors (BMPRs) localized in caveolae. BMPRIa is phosphorylated in caveolae and the disruption of caveolae‐inhibited Smad signaling in the presence of BMP2. This suggests caveolae are necessary for the initiation of Smad signaling. We propose an extension of the current model of BMP2 signaling, in which the initiation of Smad signaling is mediated by BMPRs in caveolae. J. Cell. Physiol. 227: 2880–2888, 2012. © 2011 Wiley Periodicals, Inc.
Engineered endothelial progenitor cells that overexpress prostacyclin protect vascular cells
Authors: Liu Qi , Xi Yutao , Terry Toya , So Shui‐Ping , Mohite Anita , Zhang Jia , Wu Geru , Liu Xiaobing , Cheng Jie , Ruan Ke‐He , Willerson James T. , Dixon Richard A.F.
Published: September 2011

Prostacyclin (PGI2) is a potent vasodilator and important mediator of vascular homeostasis; however, its clinical use is limited because of its short (<2‐min) half‐life. Thus, we hypothesize that the use of engineered endothelial progenitor cells (EPCs) that constitutively secrete high levels of PGI2 may overcome this limitation of PGI2 therapy. A cDNA encoding COX‐1‐10aa‐PGIS, which links human cyclooxygenase‐1 (COX‐1) to prostacyclin synthase (PGIS), was delivered via nucleofection into outgrowth EPCs derived from rat bone marrow mononuclear cells. PGI2‐secreting strains (PGI2‐EPCs) were established by continuous subculturing of transfected cells under G418 selection. Genomic PCR, RT‐PCR, and Western blot analyses confirmed the overexpression of COX‐1‐10aa‐PGIS in PGI2‐EPCs. PGI2‐EPCs secreted significantly higher levels of PGI2 in vitro than native EPCs (P < 0.05) and showed higher intrinsic angiogenic capability; conditioned medium (CM) from PGI2‐EPCs promoted better tube formation than CM from native EPCs (P < 0.05). Cell‐ and paracrine‐mediated in vitro angiogenesis was attenuated when COX‐1‐10aa‐PGIS protein expression was knocked down. Whole‐cell patch‐clamp studies showed that 4‐aminopyridine‐sensitive K+ current density was increased significantly in rat smooth muscle cells (rSMCs) cocultured under hypoxia with PGI2‐EPCs (7.50 ± 1.59 pA/pF; P < 0.05) compared with rSMCs cocultured with native EPCs (3.99 ± 1.26 pA/pF). In conclusion, we successfully created EPC strains that overexpress an active novel enzyme resulting in consistent secretion of PGI2. PGI2‐EPCs showed enhanced intrinsic proangiogenic properties and provided favorable paracrine‐mediated cellular protections, including promoting in vitro angiogenesis of native EPCs and hyperpolarization of SMCs under hypoxia. J. Cell. Physiol. 227: 2907–2916, 2012. © 2011 Wiley Periodicals, Inc.
Transplacental fetal therapy for junctional ectopic tachycardia
Authors: Ishikawa Kaori , Kikuchi Akihiko , Matsui Hikoro , Tamaru Shunsuke , Imada Shinya , Horikoshi Tsuguhiro , Takagi Kimiyo
Published: September 2011

Junctional ectopic tachycardia (JET) is a rare type of tachyarrhythmia. A 39‐year‐old woman was transferred to our hospital for fetal tachyarrhythmia at 32 weeks' gestation. Fetal cardiac sonography revealed atrial and ventricular rates of 120–130 and 175–230 bpm, respectively, without 1:1 atrioventricular relationship. As ventricular tachycardia was considered to be the most probable diagnosis, transplacental therapy with digoxin and sotalol was done with partial response. Diagnosis of JET was made after birth. Although fetal JET is rare and prenatal diagnosis and treatment of this condition is still a challenge, differential diagnosis of fetal tachyarrhythmia should include this disorder. © 2011 Wiley Periodicals, Inc. J Clin Ultrasound 40:119–123, 2012
Selectivity of some basic solutes on a poly(methyltetradecylsiloxane)‐silica stationary phase
Authors: Borges Endler M. , Collins Carol H.
Published: September 2011

Complex analyses of polar compounds, especially basic ones, require more selective stationary phases. The present paper describes a stationary phase prepared by thermal immobilization of poly(methyltetradecylsiloxane) onto chromatographic silica (PMTDS‐SiO2). This stationary phase presents hydrophobic and ion‐exchange interactions that confer both high retention and unique selectivities for basic solutes. The influence of ion‐exchange interactions is confirmed by the increase in retention factors of basic solutes when the mobile‐phase pH changes from acidic to neutral and by the decrease in retention factors when the mobile‐phase pH changes from neutral to alkaline. The ion‐exchange properties of the stationary phase are enriched in neutral mobile phase (pH 7–7.5) using soft Lewis bases such as tricine and tris as buffers but are suppressed in both acidic (pH 2.5–6) and highly alkaline mobile phases (pH≤10). Increasing both temperature and flow rate permits more rapid separations while maintaining the selectivity. The stability of the stationary phase is evaluated with acid, neutral and alkaline mobile phases.
Practical comparison of LC columns packed with different superficially porous particles for the separation of small molecules and medium size natural products
Authors: Yang Peilin , McCabe Terry , Pursch Matthias
Published: September 2011

Commercial C18 columns packed with superficially porous particles of different sizes and shell thicknesses (Ascentis Express, Kinetex, and Poroshell 120) or sub‐2‐μm totally porous particles (Acquity BEH) were systematically compared using a small molecule mixture and a complex natural product mixture as text probes. Significant efficiency loss was observed on 2.1‐mm id columns even with a low dispersion ultra‐high pressure liquid chromatography system. The Kinetex 4.6‐mm id column packed with 2.6‐μm particles exhibited the best overall efficiency for small molecule separations and the Poroshell 120 column showed better performance for mid‐size natural product analytes. The Kinetex 2.1‐mm id column packed with 1.7‐μm particles did not deliver the expected performance and the possible reasons besides extra column effect have been proved to be frictional heating effect and poor column packing quality. Different column retentivities and selectivities have been observed on the four C18 columns of different brands for the natural product separation. Column batch‐to‐batch variability that has been previously observed on the Ascentis Express column was also observed on the Kinetex and Poroshell 120 column.
Resveratrol derivative‐rich melinjo (Gnetum gnemon L.) seed extract suppresses multiple angiogenesis‐related endothelial cell functions and tumor angiogenesis
Authors: Kunimasa Kazuhiro , Ohta Toshiro , Tani Hiroko , Kato Eishin , Eguchi Ryoji , Kaji Kazuhiko , Ikeda Katsumi , Mori Hideki , Mori Mari , Tatefuji Tomoki , Yamori Yukio
Published: September 2011

Angiogenesis is a promising target for cancer prevention and treatment. This study aimed to determine the antiangiogenic effects of melinjo (Gnetum gnemon L.) seed extract and its resveratrol derivative components, such as gnetin C (GC), gnetin L (GL), gnemonoside A (GMA), gnemonoside C (GMC), and gnemonoside D (GMD). An ethanol extract of melinjo seeds (EEMS) and the two gnetins markedly inhibited the proliferation and tube formation of human umbilical vein endothelial cells (HUVEC) stimulated with vascular endothelial growth factor and basic fibroblast growth factor. The inhibitory effects of GC and GL were much stronger than those of resveratrol. GMC and GMD inhibited only proliferation, whereas GMA had almost no effect on the two endothelial cell functions. The EEMS and GC also reduced the cell viability of tube‐forming HUVEC, with accompanying ERK1/2 inactivation, and suppressed the migration of HUVEC. Furthermore, dietary intake of EEMS significantly inhibited tumor angiogenesis in a mouse dorsal air sac assay. In conclusion, we found that the EEMS and its resveratrol derivatives, particularly GC, suppress multiple angiogenesis‐related endothelial cell functions and/or tumor angiogenesis, indicating that the melinjo seeds and the natural resveratrol derivatives may be useful for cancer prevention and treatment.
Analysis of industrial c‐Si solar cell's front metallization by advanced numerical simulation
Authors: Yang Yang , Altermatt Pietro P. , Zhu Weihua , Liang Xueqin , Shen Hui
Published: September 2011

The influence of the front metallization on the performance of industrially fabricated c‐Si solar cells is quantified by means of a combination of optical, semiconductor, and circuit modeling. Special attention is given to the front metallization of conventionally processed emitters. First, we verify our model by reproducing the measured I–V curves of industrially fabricated cells. Based on this, the potential changes in performance are predicted by variations in finger spacing, finger resistivity, busbar numbers, and contact resistivity. We also assess the benefits derived from the higher aspect ratios of the fingers: if the fingers are 120 (or 60 µm) wide, increasing the finger height from 15 to 25 µm increases their efficiency by 0.06% (or 0.7%) absolute if a conventional emitter is used. This implies that, if the fingers cannot be made as narrow as 60 µm in industrial mass production, the economic gains from higher aspect ratios may be rather limited, because there is a trade‐off between improved cell efficiency and the increasing cost of silver. Simulations show that, for the light‐induced plating approach, the seed layer must be made as narrow as 50 µm in order to achieve an efficiency gain of 1% absolute with a plating of 10 µm silver. Copyright © 2011 John Wiley & Sons, Ltd.
On the purification of CVD grown boron doped single‐walled carbon nanotubes
Authors: Ruiz‐Soria G. , Ayala P. , Puchegger S. , Kataura H. , Yanagi K. , Pichler T.
Published: September 2011

In this paper, we report a facile purification method of boron‐doped single‐walled carbon nanotubes (SWCNTs) produced by high vacuum chemical vapor deposition (HV‐CVD). The raw material was doped in situ during growth, with a B content below 0.5 at.%, estimated by means of X‐ray photoelectron spectroscopy (XPS). Using ultracentrifugation combined with a mild acid solution pH neutralization, we have proved it is feasible to purify this material, which originally contains synthesis byproducts that differ from the typical catalytic remaining in pristine carbon nanotube samples produced with a similar method. The diameter size and distribution – previous and after purification – have been monitored by multi‐frequency Raman spectroscopy.
USE OF HYDRAULIC MODELLING TO ASSESS PASSAGE FLOW CONNECTIVITY FOR SALMON IN STREAMS
Authors: Grantham T. E.
Published: September 2011

The maintenance of hydrologic connectivity in river networks has become an important principle for guiding management and conservation planning for threatened salmon populations, yet our understanding of how fish movement is impaired by spatial and temporal variation in connectivity remains limited. In this study, a two‐dimensional hydraulic modelling approach is presented to evaluate flow connectivity in relation to passage requirements of adult steelhead trout (Oncorhynchus mykiss) in coastal California streams. High‐resolution topographic data of stream reaches with distinct channel morphology were collected using terrestrial light detection and ranging surveys and linked with water surface measurements to calibrate hydraulic model simulations. Quantitative metrics of longitudinal flow connectivity were developed to assess fish passage suitability in relation to stream discharge. Measured flow data from the 2008–2009 winter season and simulated long‐term records indicated that suitable passage flows occur with relatively low frequency and duration at all sites, suggesting that instream flow protections for fish passage are warranted. Results from the hydraulic modelling simulations were then compared with two alternative methods for assessing passage flows. A regional formula used by the State of California to identify minimum instream flow needs provided conservative estimates of passage flow requirements, whereas an approach based on riffle crest water depths underestimated flow needs. The hydraulic modelling approach appears well suited for simulating flows for fish passage studies and may be particularly useful for testing alternative environmental flow assessment methods and evaluating habitat–flow relationships in stream reaches of importance, such as critical habitat for threatened fish species. Copyright © 2011 John Wiley & Sons, Ltd.
Secured hierarchical secret sharing using ECC based signcryption
Authors: Basu Atanu , Sengupta Indranil , Sing Jamuna Kanta
Published: September 2011

Most of the existing hierarchical secret‐sharing schemes are unconditionally (non‐cryptographically) secured, and they cannot survive from various types of attacks especially when the participants use resource‐constrained wireless mobile devices. In our proposed secured hierarchical secret‐sharing scheme, the participants are partitioned into different levels according to their ranks in any organization. In this hierarchy‐based secret‐sharing scheme, the trusted dealer distributes the delegated secret keys as shares to the participants through our proposed signcryption scheme that reduces computational cost and communication overhead. Again, the participants submit the signcrypted shares to the trusted dealer for reconstruction of the secret key. The proposed scheme distinguishes each level of hierarchy qualitatively, and any type of active or passive adversary or colluding participants cannot reconstruct the secret key. The novelty of our scheme is that it is conditionally (cryptographically) as well as unconditionally secured, and the participants may use resource‐constrained wireless mobile devices. The access structure chosen for our scheme increases the resilience of our scheme. Our proposed scheme is perfect and ideal. Copyright © 2011 John Wiley & Sons, Ltd.
VeriEST: verification via primary user emulation signal‐based test for secure distributed spectrum sensing in cognitive radio networks
Authors: Kim Mihui , Chung Min Young , Choo Hyunseung
Published: September 2011

Secure distributed spectrum sensing (DSS) schemes in cognitive radio networks (CRNs) have been proposed to reliably detect the signals of the primary users (PUs) even when compromised nodes generate forged sensing reports. However, they have limited sensing accuracy for PU signals because of the absence of exact signal patterns of PUs. This is caused by Federal Communications Commission restriction on (no modification of) PUs, and thus, the CRNs cannot communicate with the PUs to obtain such patterns. We propose a verification framework utilizing primary user emulation signals that can be applied to existing DSS schemes to address this challenge. This will reinforce the robustness against forged sensing values. We then develop a concrete verification scheme based on this framework and an existing secure DSS scheme. We evaluate our approach via in‐depth simulation and analysis compared with the existing scheme. Results show that our approach improves sensing accuracy and fusion speed in the cases of attack. Copyright © 2011 John Wiley & Sons, Ltd.
α‐Amylase immobilization on functionalized nano CaCO3 by covalent attachment
Authors: Demir Serap , Gök Sevda Burcu , Kahraman Memet Vezir
Published: September 2011

In this study, α‐amylase was immobilized on glutaraldehyde activated silanized calcium carbonate nanoparticles by a using covalent binding method. The surface modified nano calcium carbonate (CaCO3) were characterized using FTIR and SEM. Immobilization yield was found as 199.43 mg/g of calcium carbonate nanoparticles. The maximum activity was observed at pH 6.5. The immobilized enzyme had a higher activity at elevated temperature (50–90°C) than the free one. Reuse studies demonstrated that the immobilized enzyme could reuse 25 times while retaining 18.2% of its activity. Free enzyme lost its activity completely within 15 days. Vmax values for the free and immobilized enzymes were calculated as 10 and 0.35 mg/mL/min, respectively.
Characterisation of normal corn starch using asymmetrical flow field‐flow fractionation
Authors: Juna Shazia , Huber Anton
Published: September 2011

The apparent average molar masses (Mw,app), apparent average radii of gyration (Rg,app), diffusion co‐efficients (DT), and hydrodynamic radii (Rh) of normal corn (maize) starch and fractions were determined using asymmetrical flow field‐flow fractionation coupled with multi‐angle light scattering and refractive index detectors (AF4/MALS/RI). AM‐type (Fraction A) and AP‐type (Fraction B) were chemically separated from normal corn starch. Normal corn starch and Fractions (A–B) were dissolved in 1 M KSCN using a high pressure microwave vessel. The effect of varying cross flow rates at a fixed channel flow rate upon the Mw,app and Rg,app distributions of normal corn starch and Fractions (A–B) were investigated. The average Mw,app of normal corn starch, Fractions (A) and Fraction (B) were 41 × 106, 1.4 × 106 and 39 × 106 g/mol, respectively, with Rg,app values of 129, 60 and 129 nm, respectively.
Evaluating cost‐efficiency and accuracy of hunter harvest survey designs
Authors: Lukacs Paul M. , Gude Justin A. , Russell Robin E. , Ackerman Bruce B.
Published: September 2011

Effective management of harvested wildlife often requires accurate estimates of the number of animals harvested annually by hunters. A variety of techniques exist to obtain harvest data, such as hunter surveys, check stations, mandatory reporting requirements, and voluntary reporting of harvest. Agencies responsible for managing harvested wildlife such as deer (Odocoileus spp.), elk (Cervus elaphus), and pronghorn (Antilocapra americana) are challenged with balancing the cost of data collection versus the value of the information obtained. We compared precision, bias, and relative cost of several common strategies, including hunter self‐reporting and random sampling, for estimating hunter harvest using a realistic set of simulations. Self‐reporting with a follow‐up survey of hunters who did not report produces the best estimate of harvest in terms of precision and bias, but it is also, by far, the most expensive technique. Self‐reporting with no follow‐up survey risks very large bias in harvest estimates, and the cost increases with increased response rate. Probability‐based sampling provides a substantial cost savings, though accuracy can be affected by nonresponse bias. We recommend stratified random sampling with a calibration estimator used to reweight the sample based on the proportions of hunters responding in each covariate category as the best option for balancing cost and accuracy. © 2011 The Wildlife Society.
Explaining Regional Differences in Black Earnings Discrimination among Full-time Working Men
Authors: Mar Don
Published: September 2011

Using data from the 2000 Census 1% PUMS, this paper analyzes the causes of regional differences in Black earnings discrimination. The methodology is a two stage process used to generate and analyze a cross section of earnings discrimination across cities. In the first stage, a city measure of discrimination is constructed using the Oaxaca decomposition method. The second stage then utilizes these estimated measures of discrimination as a dependent variable in OLS models to test various discrimination theories. While the second stage offers some evidence that increases in the size of both the Black labor force and immigrant labor force are positively related to greater discrimination, increasing overall income inequality is found to robustly increase Black earnings discrimination.
Quand les migrants se choisissent : qualification sociale et sélection des postulants à la migration au Maroc
Authors: El Miri Mustapha
Published: September 2011

Our study explores the various forms of social regulation imposed on candidates for emigration in a Moroccan town. This system of judgments, based on a preliminary qualification/disqualification of the candidates at the outset, gives preference to long-term migration by according such emigrants high social prestige in their home country. Thus, to counter the stereotype of a miserable, isolated, and passive migrant, we offer the image of a strategic migrant, who has been “qualified” by local social authorities and who is aligned with a project of collective mobility.
A Moving Target: Democracy
Authors: Markoff John
Published: September 2011

Achieving consensus on a definition of “democracy” has proven elusive. Institutions that have been taken to be essential to democracy have changed radically since the word “democrat” began to be widely used toward the end of the eighteenth century. Democratic ideas and democratic practice engender conflict that transforms institutions rather than just reproduces them. Its transformative character rests on a half-dozen key attributes of democracy: it is an actor’s concept, as well as an analyst’s; it can arouse strong feelings; it combines not always compatible ideas; it empowers dissent; it involves a dynamic mixture of inclusion and exclusion; and the democratic histories of national states have been intertwined with global domination. Two processes combine to generate much social dynamism. First, democracy’s stirring inclusionary claims have been contradicted by a complex structure of exclusions, including distinctions in rights of full participation among citizens, distinctions in rights between citizens and non-citizens, and distinctions in resources among legally equal citizens. And second, democratic practice has been fertile soil for the development of social movements. Taken together, democracy is an invitation for movements to try to shift the boundaries of inclusion and exclusion, and in so doing to expand or constrict democracy itself.
Treatment with oligonol, a low-molecular polyphenol derived from lychee fruit, attenuates diabetes-induced hepatic damage through regulation of oxidative stress and lipid metabolism
Authors: Noh Jeong Sook , Park Chan Hum , Yokozawa Takako
Published: September 2011

We have identified the effects of oligonol, a low-molecular polyphenol derived from lychee fruit, on oxidative stress and lipid metabolism in a type 2 diabetic model. Oligonol was orally administered at 10 or 20 mg per kg body weight per d for 8 weeks todb/dbmice, and its effects were compared with those of the vehicle indb/dbandm/mmice. Serum and hepatic biochemical factors, and protein and mRNA expression related to lipid metabolism were measured. In the oligonol-administered group, there were significant reductions of reactive oxygen species (ROS), lipid peroxidation, and the TAG and total cholesterol concentrations in both the serum and liver. Additionally, oligonol attenuated oxidative stress through the inhibition of advanced glycation endproduct formation and its receptor expression. Furthermore, augmented expressions of NF-κBp65 and inducible NO synthase were down-regulated to the levels ofm/mmice in the group treated with oligonol at 20 mg/kg. Regarding lipid metabolism, lower hepatic lipid resulted from the down-regulation of sterol regulatory element-binding protein-1 and its target gene of lipogenic enzymes in the liver ofdb/dbmice. The present results suggest that oligonol has protective effects against ROS-related inflammation and excess lipid deposition in the type 2 diabetic liver.
ASSESSING THE UTILIZATION OF MATERNAL AND CHILD HEALTH CARE AMONG MARRIED ADOLESCENT WOMEN: EVIDENCE FROM INDIA
Authors: SINGH LUCKY , RAI RAJESH KUMAR , SINGH PRASHANT KUMAR
Published: September 2011

This study explores the prevalence and factors associated with the utilization of maternal and child health care services among married adolescent women in India using the third round of the National Family Health Survey (2005–06). The findings suggest that the utilization of maternal and child health care services among adolescent women is far from satisfactory in India. A little over 10% of adolescent women utilized antenatal care, about 50% utilized safe delivery services and about 41% of the children of adolescent women received full immunization. Large differences by urban–rural residence, educational attainment, religion, economic status and region were evident. Both gross effect and fixed effect binary logit models yielded statistically significant socioeconomic and demographic factors. Women's education, wealth quintile and region are the most important determinants for the utilization of maternal and child health care services. Health care programmes should focus more on educating adolescents, providing financial support, creating awareness and counselling households with married adolescent women. Moreover, there should be substantial financial assistance for the provision of delivery and child care for married women below the age of 19 years.