bluuebunny/crossref_metadata_2025 huggingface dataset:
Fundamentals of stand‐off Raman scattering spectroscopy for explosive fingerprinting
Authors: Moros Javier , Lorenzo Juan Antonio , Novotný Karel , Laserna J. Javier
Published: November 2012

The fact that a Raman spectrum may be considered the fingerprint of an interrogated target by providing specific information on the particular chemical structures of the molecules present, has boosted the use of Raman spectroscopy for explosives detection in homeland and security applications. Also, the possibility of direct and distant access to suspect targets by stand‐off Raman measurements makes this analytical technique a valuable tool in operational scenarios for security forces. The modest detection power as a result of the well‐known, inherently low efficiency of the Raman scattering requires a careful evaluation of the experimental parameters governing the analytical response of this technique, particularly in respect to the amenable distance to target, the data acquisition speed, and the sources of uncertainty in any given measurement. The present paper highlights the importance of adequate instrumental parameters of the sensor according to the operational scenario when analyzing unknown targets. Raman fingerprints collected from a wide range of high explosives and associated compounds under different analysis conditions and operational scenarios have been evaluated in terms of signal strength, signal‐to‐noise ratio, analytical sensitivity, and signal stability. Copyright © 2012 John Wiley & Sons, Ltd.
Investigation of organelle‐specific intracellular water structures with Raman microspectroscopy
Authors: Tiwari Shraeddha , Ando Masahiro , Hamaguchi Hiro‐o
Published: November 2012

The study of intracellular water in living cells is a challenge of fundamental importance. While the critical roles of water in maintaining and propagating life have been widely recognized and accepted, our understanding of water/biomolecule interactions is surprisingly limited. Using Raman microspectroscopic imaging of a living yeast cell followed by a multivariate analysis in form of the nonnegative matrix factorization method, we successfully resolve organelle‐specific water structures. The intensities and the band profiles of the segregated water OH stretch spectra yield important and otherwise unobtainable information on the extensive effect of the water/biomolecule interactions in a given organelle on the hydrogen‐bonding network of water molecules. Copyright © 2012 John Wiley & Sons, Ltd.
Top‐emission AMOLED display driven by organic TFTs with semiconductor layer patterned by inkjet process
Authors: Okumoto Yuko , Ukeda Takaaki , Matsui Masafumi , Okumoto Kenji , Miyamoto Akihito , Morita Kiyoyuki
Published: November 2012

We have developed an inkjet process for laying down an organic semiconductor layer in organic thin‐film transistors (OTFTs). The organic semiconductor crystallinity was improved by adjusting the contact angles of the bank, the gate insulator, and the source/drain electrodes. The threshold voltage of the OTFT was controlled by means of several surface treatments of the silicon dioxide gate insulator. The OTFTs showed a high mobility of 2.5 cm2/Vs and uniform threshold voltages of −0.4 ± 0.7 V. We also fabricated a 4‐in., 80‐ppi active‐matrix organic light‐emitting diode on a glass substrate that showed good luminance uniformity and high moving picture quality.
Features of Double‐Spiral “Valley‐Hills” Surface Topography Formation in Photochromic Cholesteric Oligomer‐Based Films and Their Changes Under Polarized Light Action
Authors: Bobrovsky Alexey , Mochalov Konstantin , Chistyakov Anton , Oleinikov Vladimir , Shibaev Valery
Published: November 2012

Using a novel experimental method combining of polarizing optical microscopy (POM) and atomic force microscopy (AFM), the surface topography and optical properties of chiral‐ photochromic LC systems were studied. For this purpose, a mixture of cholesteric cyclosiloxanes with azobenzene‐containing dopant was prepared. Correlations between the features of surface topography of mixture films and POM images of planarly oriented texture were found. Polarized light action (532 nm) leads to the formation of partially aligned surface structure features. The observed photooptical effects are associated with E‐Z, Z‐E isomerization cycles of azobenzene groups, anisotropic cooperative photoinduced rotational diffusion and directional mass‐transport of chromophores and mesogens in the films.
Irregularity and the period determinant for irregular singular connections on surfaces
Authors: Hien M.
Published: November 2012

In [6], we constructed a period pairing for flat irregular singular conncetions on surfaces. We now extend these constructions to a perfect period pairing between the irregularity complex of the connection and the complex of relative rapid decay chains. As a consequence, the period determinant of the connection decomposes as a product of a topological period determinant on the open surface and a determinant coming from the irregularity of the connection. Additionally, we deduce a method to compute the irregularity sheaf up to local isomorphism in topological terms (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Association of Tef polymorphism with depression in Parkinson disease
Authors: Hua Ping , Liu Weiguo , Kuo Sheng‐Han , Zhao Yanyan , Chen Ling , Zhang Ning , Wang Chun , Guo Suwan , Wang Li , Xiao Hong , Kwan Justin Y. , Wu Tianxia
Published: November 2012

Background:

Circadian rhythm disturbance has been implicated in depression, and polymorphisms of circadian genes Cry1, Cry2, and Tef are associated with depression. However, the relationship between these genes and depression symptoms in Parkinson's disease (PD) has not been established.

Methods:

Four hundred eight subjects with PD participated in this study. Demographics, UPDRS, Mini–Mental Status Examination (MMSE), and Hamilton Rating Scale for Depression (HAMD) were obtained in all subjects. Frequency of polymorphisms of Cry1 rs2287161, Cry2 rs10838524, and Tef rs738499 was determined, and the association between genetic polymorphisms of circadian genes and HAMD scores in patients with PD was examined.

Results:

Tef, but not Cry1 or Cry2, is associated with HAMD scores in patients with PD in a linear regression model after adjusting for clinical variables (P = 0.004).

Conclusions:

The polymorphism of Tef rs738499 is associated with depression symptoms in PD. © 2012 Movement Disorder Society
Folate, alcohol, and liver disease
Authors: Medici Valentina , Halsted Charles H.
Published: November 2012

Alcoholic liver disease (ALD) is typically associated with folate deficiency, which is the result of reduced dietary folate intake, intestinal malabsorption, reduced liver uptake and storage, and increased urinary folate excretion. Folate deficiency favors the progression of liver disease through mechanisms that include its effects on methionine metabolism with consequences for DNA synthesis and stability and the epigenetic regulation of gene expression involved in pathways of liver injury. This paper reviews the pathogenesis of ALD with particular focus on ethanol‐induced alterations in methionine metabolism, which may act in synergy with folate deficiency to decrease antioxidant defense as well as DNA stability while regulating epigenetic mechanisms of relevant gene expressions. We also review the current evidence available on potential treatments of ALD based on correcting abnormalities in methionine metabolism and the methylation regulation of relevant gene expressions.
Architecture of healthy and dystrophic muscles detected by optical coherence tomography
Authors: Lovering Richard M. , Shah Sameer B. , Pratt Stephen J.P. , Gong Wei , Chen Yu
Published: November 2012

Introduction: The ability to view individual myofibers is possible with many histological techniques, but not yet with standard in vivo imaging. Optical coherence tomography (OCT) is an emerging technology that can generate high resolution 1–10 μm cross‐sectional imaging of tissue in vivo and in real time. Methods: We used OCT to determine architectural differences of tibialis anterior muscles in situ from healthy mice (wild‐type [WT], n = 4) and dystrophic mice (mdx, n = 4). After diffusion tensor imaging (DTI) and OCT, muscles were harvested, snap‐frozen, and sectioned for staining with wheat germ agglutinin. Results: DTI suggested differences in pennation and OCT was used to confirm this supposition. OCT indicated a shorter intramuscular tendon (WT/mdx ratio of 1.2) and an 18% higher degree of pennation in mdx. Staining confirmed these architectural changes. Conclusions: Architectural changes in mdx muscles, which could contribute to reduction of force, are detectable with OCT. Muscle Nerve, 2013
Physikalische Chemie 2007
Authors: Meijer Gerard , Küpper Jochen
Published: November 2012

Kalte Moleküle erlauben faszinierende Experimente: von der hochaufgelösten Spektroskopie bis zur Chemie, bei der Tunnelprozesse die Reaktionen dominieren. Kohlenstoffnanostrukturen bieten großes Anwendungspotenzial für die molekulare Elektronik. Mit Freie‐Elektronen‐Lasern verbindet sich die Hoffnung, chemische Reaktionen in Raum und Zeit mit atomarer Auflösung zu verfolgen.
Glucocorticoidhaltige Magistralrezepturen. Rationaler Einsatz in der Dermatologie
Authors: Högger Petra
Published: November 2012

Topisch angewandte Glucocorticoide spielen in der Therapie entzündlicher Hauterkrankungen eine zentrale Rolle. Eine hohe Konzentration am Wirkort und eine geringe Rate unerwünschter Wirkungen führen zu einer hohen Effektivität und Sicherheit der Behandlung. Kenntnisse der Wirkstoffkinetik und ‐dynamik, aber auch der Vehikeleinflüsse, sind die Grundlage für das Verständnis der erwünschten und unerwünschten Effekte und für eine erfolgreiche Therapie.
Spins unter Kontrolle
Authors: Kronast Florian
Published: November 2012

Die Spintronik verspricht kleinere, schnellere und energiesparendere Bauteile im Vergleich zu herkömmlicher Elektronik. Sie ist keine Zukunftsvision mehr; spintronische Bauteile halten mittlerweile Einzug in technische Dinge wie Festplatten und Sensoren (Phys. unserer Zeit 2008, 39 (6), 274). Vincent Garcia und seinen Kollegen von der Unité Mixte de Physique CNRS/Thales ist jüngst in einer internationalen Zusammenarbeit, an der auch unsere Gruppe vom Helmholtz‐Zentrum‐Berlin für Materialien und Energie beteiligt war, ein großer Fortschritt mit der ferroelektrischen Kontrolle der Spin‐Polarisation gelungen.
Quantitative proteomic analysis to decipher the differential apoptotic response of bortezomib‐treated APL cells before and after retinoic acid differentiation reveals involvement of protein toxicity mechanisms
Authors: Uttenweiler‐Joseph Sandrine , Bouyssié David , Calligaris David , Lutz Pierre G. , Monsarrat Bernard , Burlet‐Schiltz Odile
Published: November 2012

The ubiquitin‐proteasome system allows the targeted degradation of proteins and plays a critical role in the regulation of many cellular processes. Proteasome inhibition is a recent antitumor therapeutic strategy and bortezomib was the first proteasome inhibitor approved for clinical use. In this study, we used the NB4 cell line to investigate the effects of bortezomib toward acute promyelocytic leukemia cells before and after retinoic acid‐induced differentiation. We showed that apoptosis level after bortezomib treatment is higher in NB4 cells than in differentiated NB4 cells. To compare early protein variations upon bortezomib treatment in both NB4 cell populations, we performed a quantitative proteomic analysis based on iTRAQ peptide labeling followed by data analysis with in‐house developed scripts. This strategy revealed the regulation of 14 proteins principally involved in protein stress response and apoptosis in NB4 cells after proteasome inhibition. Altogether, our results suggest that the differential level of apoptosis induced by bortezomib treatment in both NB4 cell populations could result from distinct protein toxicity level.
Ring‐opening polymerization of lactides catalyzed by magnesium complexes coordinated with NNO‐tridentate pyrazolonate ligands
Authors: Chuang Hui‐Ju , Chen Hsiao‐Li , Ye Jian‐Li , Chen Zn‐Yun , Huang Pei‐Ling , Liao Tzu‐Ting , Tsai Tsung‐En , Lin Chu‐Chieh
Published: November 2012

A series of magnesium benzylalkoxide complexes, [LnMg(μ‐OBn)]2 (1–14) supported by NNO‐tridentate pyrazolonate ligands with various electron withdrawing‐donating subsituents have been synthesized and characterized. X‐ray crystal structural studies revealed that Complexes 1–3, 5, 7, 9, and 10 are dinuclear bridging through benzylalkoxy oxygen atoms with penta‐coordinated metal centers. All of these complexes acted as efficient initiators for the ring‐opening polymerization of L‐lactide and rac‐lactide. Based on kinetic studies, the activity of these metal complexes is significantly influenced by the electronic effect of the ancillary ligands with the electron‐donating substituents at the phenyl rings enhancing the polymerization rate. In addition, the “living” and “immortal” character of 6 has paved a way to synthesize as much as 40‐fold polymer chains of polylactides with a very narrow polydispersity index in the presence of a small amount of initiator. Among all of magnesium complexes, Complex 6 exhibits the highest stereoselectivity toward ring‐opening polymerization of rac‐lactide with Pr up to 88% in THF at 0 °C. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Synthesis and characterization of Y‐type polymers for second‐order nonlinear optical applications
Authors: Kolli Balakrishna , Mishra Sarada P. , Palai Akshaya K. , Kanai Tapan , Joshi M. P. , Mohan S. Raj , Dhami T. S. , Kukreja L. M. , Samui A. B.
Published: November 2012

A series of dicyanomethylene‐substituted polymers having Y‐type molecular architecture were synthesized by Knoevenagel condensation reaction. The polymers were found to be soluble in organic solvents like tetrahydrofuran and chloroform. From gel permeation chromatography, the molecular weights of the polymers were found to be in the range of 15,300–33,800 g/mol. Thermal analysis showed that the polymers were stable up to 350 °C with glass transition temperature (Tg) in the range of 129–212 °C. These polymers were found to form good optical quality films. The order parameter was calculated to be in the range of 0.01–0.48. Atomic force microscopy indicated prominent morphology changes due to alignment of dipoles after poling. By using Nd:YAG laser of 1064 nm, angular dependence and temperature dependence of second‐harmonic generation intensity were investigated. The geometry optimization, shape of polymers, and restricted torsion angle between acceptor and donor substituents (push–pull system) were calculated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
Multiple binding modes for palmitate to barley lipid transfer protein facilitated by the presence of proline 12
Authors: Smith Lorna J. , Gunsteren Wilfred F. Van , Allison Jane R.
Published: November 2012

Molecular dynamics simulations have been used to characterise the binding of the fatty acid ligand palmitate in the barley lipid transfer protein 1 (LTP) internal cavity. Two different palmitate binding modes (1 and 2), with similar protein–ligand interaction energies, have been identified using a variety of simulation strategies. These strategies include applying experimental protein–ligand atom–atom distance restraints during the simulation, or protonating the palmitate ligand, or using the vacuum GROMOS 54B7 force‐field parameter set for the ligand during the initial stages of the simulations. In both the binding modes identified the palmitate carboxylate head group hydrogen bonds with main chain amide groups in helix A, residues 4 to 19, of the protein. In binding mode 1 the hydrogen bonds are to Lys 11, Cys 13, and Leu 14 and in binding mode 2 to Thr 15, Tyr 16, Val 17, Ser 24 and also to the OH of Thr 15. In both cases palmitate binding exploits irregularity of the intrahelical hydrogen‐bonding pattern in helix A of barley LTP due to the presence of Pro 12. Simulations of two variants of barley LTP, namely the single mutant Pro12Val and the double mutant Pro12Val Pro70Val, show that Pro 12 is required for persistent palmitate binding in the LTP cavity. Overall, the work identifies key MD simulation approaches for characterizing the details of protein–ligand interactions in complexes where NMR data provide insufficient restraints.
A comparison of successful and failed protein interface designs highlights the challenges of designing buried hydrogen bonds
Authors: Stranges P. Benjamin , Kuhlman Brian
Published: November 2012

The accurate design of new protein–protein interactions is a longstanding goal of computational protein design. However, most computationally designed interfaces fail to form experimentally. This investigation compares five previously described successful de novo interface designs with 158 failures. Both sets of proteins were designed with the molecular modeling program Rosetta. Designs were considered a success if a high‐resolution crystal structure of the complex closely matched the design model and the equilibrium dissociation constant for binding was less than 10 μM. The successes and failures represent a wide variety of interface types and design goals including heterodimers, homodimers, peptide‐protein interactions, one‐sided designs (i.e., where only one of the proteins was mutated) and two‐sided designs. The most striking feature of the successful designs is that they have fewer polar atoms at their interfaces than many of the failed designs. Designs that attempted to create extensive sets of interface‐spanning hydrogen bonds resulted in no detectable binding. In contrast, polar atoms make up more than 40% of the interface area of many natural dimers, and native interfaces often contain extensive hydrogen bonding networks. These results suggest that Rosetta may not be accurately balancing hydrogen bonding and electrostatic energies against desolvation penalties and that design processes may not include sufficient sampling to identify side chains in preordered conformations that can fully satisfy the hydrogen bonding potential of the interface.
Antibacterial and membrane‐damaging activities of β‐bungarotoxin B chain
Authors: Wen Yi‐Lin , Wu Bao‐Jueng , Kao Pei‐Hsiu , Fu Yaw‐Syan , Chang Long‐Sen
Published: November 2012

This study investigates whether the B chain of β‐bungarotoxin exerted antibacterial activity against Escherichia coli (Gram‐negative bacteria) and Staphylococcus aureus (Gram‐positive bacteria) via its membrane‐damaging activity. The B chain exhibited a growth inhibition effect on E. coli but did not show a bactericidal effect on S. aureus. The B‐chain bactericidal action on E. coli positively correlated with an increase in membrane permeability in the bacterial cells. Lipopolysaccharide (LPS) layer destabilization and lipoteichoic acid (LTA) biosynthesis inhibition in the cell wall increased the B‐chain bactericidal effect on E. coli and S. aureus. The B chain induced leakage and fusion in E. coli and S. aureus membrane‐mimicking liposomes. Compared with LPS, LTA notably suppressed the membrane‐damaging activity and fusogenicity of the B chain. The B chain showed similar binding affinity with LPS and LTA, whereas LPS and LTA binding differently induced B‐chain conformational change as evidenced by the circular dichroism spectra. Taken together, our data indicate that the antibacterial action of the B chain is related to its ability to induce membrane permeability and suggest that the LPS‐induced and LTA‐induced B‐chain conformational change differently affects the bactericidal action of the B chain. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd.
On the Performance of Auxiliary‐based Control Charting under Normality and Nonnormality with Estimation Effects
Authors: Riaz Muhammad , Mehmood Rashid , Ahmad Shabbir , Abbasi Saddam Akber
Published: November 2012

Process monitoring through control charts is a quite popular practice in statistical process control. From a statistical point of view, a superior control chart is the one which has an efficient design structure, for the case of both known and unknown parameters. There are auxiliary information–based location charts for an improved monitoring of process mean level. These charting structures have some limitations like assuming normality, the parameters to be known and focusing mainly on phase I monitoring. In many practical situations, nonnormal process behaviors are more frequent. Information about process parameters is not available, and we have to rely on the limited data available from the process to establish the limits in phase I and then use them in phase II monitoring. To have a compromise between the statistical and the practical purposes, a natural desire is to have a control chart that can serve both the concerns efficiently. This study is planned for the same objective focusing the auxiliary‐based Shewhart's control charts for location parameter. We have investigated the properties of the design structures of different location charts based on some already used and some new estimators with known and unknown parameters for normal and nonnormally distributed processes. By evaluating the performance of different charting structures in terms of power and run length properties in phase I and phase II, we have identified those more capable of making a good compromise between the abovementioned purposes in terms of statistical efficiency and practical desires. Copyright © 2012 John Wiley & Sons, Ltd.
Probing the dynamic reversibility and generation of dynamic combinatorial libraries in the presence of bacterial model oligopeptides as templating guests of tetra‐carbohydrazide macrocycles using electrospray mass spectrometry
Authors: Nour Hany F. , Islam Tuhidul , Fernández‐Lahore Marcelo , Kuhnert Nikolai
Published: November 2012

RATIONALE

Over the past few decades, bacterial resistance to antibiotics has emerged as a real threat to human health. Accordingly, there is an urgent demand for the development of innovative strategies for discovering new antibiotics. We present the first use of tetra‐carbohydrazide cyclophane macrocycles in dynamic combinatorial chemistry (DCC) and molecular recognition as chiral hosts binding oligopeptides, which mimic bacterial cell wall. This study introduces an innovative application of electrospray ionisation time‐of‐flight mass spectrometry (ESI‐TOF MS) to oligopeptides recognition using DCC.

METHODS

A small dynamic library composed of eight functionalised macrocycles has been generated in solution and all members were characterised by ESI‐TOF MS. We also probed the dynamic reversibility and mechanism of formation of tetra‐carbohydrazide cyclophanes in real‐time using ESI‐TOF MS.

RESULTS

Dynamic reversibility of tetra‐carbohydrazide cyclophanes is favored under thermodynamic control. The mechanism of formation of tetra‐carbohydrazide cyclophanes involves key dialdehyde intermediates, which have been detected and assigned according to their high‐resolution m/z values. Three members of the dynamic library bind efficiently in the gas phase to a selection of oligopeptides, unique to bacteria, allowing observation of host/guest complex ions in the gas phase.

CONCLUSIONS

We probed the mechanism of the [2+2]‐cyclocondensation reaction forming library members, proved dynamic reversibility of tetra‐carbohydrazide cyclophanes and showed that complex ions formed between library members and hosts can be observed in the gas phase, allowing the solution of an important problem of biological interest. Copyright © 2012 John Wiley & Sons, Ltd.
Confident identification of isomeric N‐glycan structures by combined ion mobility mass spectrometry and hydrophilic interaction liquid chromatography
Authors: Yamaguchi Yoshiki , Nishima Wataru , Re Suyong , Sugita Yuji
Published: November 2012

RATIONALE

A central issue in glycan mass analysis is the ambiguity of structural assignments due to the heterogeneity and complexity of glycan structures. Ion mobility mass spectrometry (IM‐MS) has the potential to separate isomeric glycans depending on their unique collisional cross section especially when coupled with hydrophilic interaction liquid chromatography (HILIC).

METHODS

Ten pyridylaminated biantennary N‐glycans including isomeric structures were measured by electrospray ionization quadrupole‐time‐of‐flight mass spectrometry with an ion mobility phase. We investigated which adduct ions would be suitable for good separation in the ion mobility phase. The differences in observed drift time of isomeric glycans were assessed by molecular dynamics (MD) simulations in vacuum. Connecting an HILIC system with IM‐MS provided another, augmented separation mode.

RESULTS

By selecting doubly protonated precursor ion species, we succeeded in separating a pair of isomeric glycans in the ion mobility phase with reasonable resolution. MD simulations of monogalactosylated glycan isomers indicate that the galactosylated Man α1‐3 branch preferentially folds back to the core chitobiose portion to form a compact structure. IM‐MS combined with HILIC resulted in even clearer separation of isomeric glycans within 15 min.

CONCLUSIONS

A combination of IM‐MS with an HILIC system is eminently suitable for the confident and rapid distinction of glycan structures within a defined mixture. Copyright © 2012 John Wiley & Sons, Ltd.
Metal cation detection in positive ion mode electrospray ionization mass spectrometry using a tetracationic salt as a gas‐phase ion‐pairing agent: Evaluation of the effect of chelating agents on detection sensitivity
Authors: Xu Chengdong , Dodbiba Edra , Padivitage Nilusha L. T. , Breitbach Zachary S. , Armstrong Daniel W.
Published: November 2012

RATIONALE

The detection of metal cations continues to be essential in many scientific and industrial areas of interest. The most common electrospray ionization mass spectrometry (ESI‐MS) approach involves chelating the metal ions and detecting the organometallic complex in the negative ion mode. However, it is well known that negative ion mode ESI‐MS is generally less sensitive than the positive ion mode. To achieve greater sensitivity, it is necessary to examine the feasibility of detecting the chelated metal cations in positive ion mode ESI‐MS.

METHODS

Since highly solvated native metal cations have relatively low ionization efficiency in ESI‐MS, and can be difficult to detect in the positive ion mode, a tetracationic ion‐pairing agent was added to form a complex with the negatively charged metal chelate. The use of the ion‐pairing agent leads to the generation of an overall positively charged complex, which can be detected at higher m/z values in the positive ion mode by electrospray ionization linear quadrupole ion trap mass spectrometry.

RESULTS

Thirteen chelating agents with diverse structures were evaluated in this study. The nature of the chelating agent played as important a role as was previously determined for cationic pairing agents. The detection limits of six metal cations reached sub‐picogram levels and significant improvements were observed when compared to negative ion mode detection where the metal‐chelates were monitored without adding the ion‐pairing reagent (IPR). Also, selective reaction monitoring (SRM) analyses were performed on the ternary complexes, which improved detection limits by one to three orders of magnitude.

CONCLUSIONS

With this method it was possible to analyze the metal cations in the positive ion mode ESI‐MS with the advantage of speed, sensitivity and selectivity. The optimum solution pH for this type of analysis is 5–7. Tandem mass spectrometry (MS/MS) further increases the sensitivity. Speciation is straightforward making this a broadly useful approach for the analysis of metal ions. Copyright © 2012 John Wiley & Sons, Ltd.
Component‐based security system (COMSEC) with QoS for wireless sensor networks
Authors: Kifayat Kashif , Merabti Madjid , Shi Qi , Abbas Sohail
Published: November 2012

In the last decade, many security solutions have been proposed to fulfil the security requirements of wireless sensor networks (WSNs). However, these solutions are specifically designed for particular security issues, based on different assumptions, and limited to certain WSNs applications. Can these security solutions work together to handle multiple problems at the same time? It is an interesting and difficult question. We believe good solutions in various security areas do not mean they can work together and deliver similar results, i.e. occurrence of any security weakness or attack in a particular security solution could expose the vulnerabilities of other solutions. Using these solutions together might also degrade WSN quality of service. To deal with the aforementioned issues, we therefore propose a novel component‐based security system (COMSEC) based on proactive and reactive components. Each component looks after a particular security issue and is integrated with others. The proposed system provides better secure communication, Sybil attack detection, secure data aggregation and resilience against node capture attacks and replication attacks. COMSEC has been evaluated and compared against existing schemes. Evaluation results show a significant improvement in resilience against node capture attacks, Sybil attack detection data confidentiality, privacy, memory overhead and connectivity. Copyright © 2012 John Wiley & Sons, Ltd.
Nitric Oxide Donors for Cardiovascular Implant Applications
Authors: Naghavi Noora , de Mel Achala , Alavijeh Omid Sadeghi , Cousins Brian G. , Seifalian Alexander M.
Published: November 2012

In an era of increased cardiovascular disease burden in the ageing population, there is great demand for devices that come in to contact with the blood such as heart valves, stents, and bypass grafts that offer life saving treatments. Nitric oxide (NO) elution from healthy endothelial tissue that lines the vessels maintains haemostasis throughout the vasculature. Surgical devices that release NO are desirable treatment options andN‐diazeniumdiolates andS‐nitrosothiols are recognized as preferred donor molecules. There is a keen interest to investigate newer methods by which NO donors can be retained within biomaterials so that their release and kinetic profiles can be optimized. A range of polymeric scaffolds incorporating microparticles and nanomaterials are presenting solutions to current challenges, and have been investigated in a range of clinical applications. This review outlines the application of NO donors for cardiovascular therapy using biomaterials that release NO locally to prevent thrombosis and intimal hyperplasia (IH) and enhance endothelialization in the fabrication of next generation cardiovascular device technology.
Development of a Continuous Desiliconization Process in the Hot Metal Runner of a Blast Furnace
Authors: Nakasuga Takamitsu , Kimura Sei , Mimura Tsuyoshi , Tadai Rikizo , Ito Kenji , Ono Reiji
Published: November 2012

An efficient continuous desiliconization process equipped with a mechanical stirrer in a hot metal runner was newly developed. The facility was installed during the revamping of No.3 blast furnace at Kobe Works, and the commercial operation started up successfully in January 2008. Before the installation of the commercial facility, the reaction behaviour was investigated under various experimental conditions for the application of a mechanical stirring method to continuous desiliconization treatment in the hot metal runner. Hot metal experiments at laboratory scale showed that the stirring intensity was an important factor for the process performance, and the mechanical stirring method was available for the improvement of reaction efficiency. As a result of plant tests, it was confirmed that a higher oxygen efficiency of desiliconization was achieved by the combination of runner arrangement and mechanical stirrer compared with the conventional injection of the desiliconizing agent. According to the reaction analysis of continuous desiliconization in the hot metal runner using the semi‐batch reaction model, it was estimated that the average slag‐metal residence time in the reaction region is improved due to an increased entrainment of foamed slag into the stirred metal bath in the mechanical stirring method, and therefore, it leads to a high desiliconization efficiency. Based on the experimental results, the equipment specifications and the runner design for this process were determined.
Functional random effect time‐varying coefficient model for longitudinal data
Authors: Chiou Jeng‐Min , Ma Yanyuan , Tsai Chih‐Ling
Published: November 2012

We propose a functional random effect time‐varying coefficient model to establish the dynamic relationship between the response and predictor variables in longitudinal data. This model allows us not only to interpret time‐varying covariate effects, but also to depict random effects via time‐varying profiles that are characterized by functional principal components. We develop the functional profiling‐backfitting method to estimate model components, which includes the profiling and backfitting procedures via a set of least squares type estimating equations. Asymptotic properties of the resulting estimator are obtained. Furthermore, we investigate the finite sample performance of the proposed method through simulation studies and present an application to primary biliary cirrhosis data. Copyright © 2012 John Wiley & Sons, Ltd.
MicroRNA-302 Increases Reprogramming Efficiency via Repression of NR2F2
Authors: Hu Shijun , Wilson Kitchener D. , Ghosh Zhumur , Han Leng , Wang Yongming , Lan Feng , Ransohoff Katherine J. , Burridge Paul , Wu Joseph C.
Published: November 2012

MicroRNAs (miRNAs) have emerged as critical regulators of gene expression through translational inhibition and RNA decay and have been implicated in the regulation of cellular differentiation, proliferation, angiogenesis, and apoptosis. In this study, we analyzed global miRNA and mRNA microarrays to predict novel miRNA-mRNA interactions in human embryonic stem cells and induced pluripotent stem cells (iPSCs). In particular, we demonstrate a regulatory feedback loop between the miR-302 cluster and two transcription factors, NR2F2 and OCT4. Our data show high expression of miR-302 and OCT4 in pluripotent cells, while NR2F2 is expressed exclusively in differentiated cells. Target analysis predicts that NR2F2 is a direct target of miR-302, which we experimentally confirm by reporter luciferase assays and real-time polymerase chain reaction. We also demonstrate that NR2F2 directly inhibits the activity of the OCT4 promoter and thus diminishes the positive feedback loop between OCT4 and miR-302. Importantly, higher reprogramming efficiencies were obtained when we reprogrammed human adipose-derived stem cells into iPSCs using four factors (KLF4, C-MYC, OCT4, and SOX2) plus miR-302 (this reprogramming cocktail is hereafter referred to as “KMOS3”) when compared to using four factors (“KMOS”). Furthermore, shRNA knockdown of NR2F2 mimics the over-expression of miR-302 by also enhancing reprogramming efficiency. Interestingly, we were unable to generate iPSCs from miR-302a/b/c/d alone, which is in contrast to previous publications that have reported that miR-302 by itself can reprogram human skin cancer cells and human hair follicle cells. Taken together, these findings demonstrate that miR-302 inhibits NR2F2 and promotes pluripotency through indirect positive regulation of OCT4. This feedback loop represents an important new mechanism for understanding and inducing pluripotency in somatic cells.
Multiplying the Effect of Professional Development: Teachers Training Teachers
Authors: Hansen‐Thomas Holly , Casey Patricia (Pat) J. , Grosso Liliana
Published: November 2012

This article describes the effects of participation and collaboration in an in‐service professional development project for secondary content area teachers referred to as turnaround training. The participating teachers were experienced, skilled practitioners in their content areas (math, science, social studies, or English language arts) who were challenged with meeting the needs of students who were learning English as well as course content. The goal of the professional development project was to improve student performance by enhancing the skills of the secondary teachers. The authors found that the training project enhanced the technical skills of participants for working with English language learners. Furthermore, these newly minted English as a second language (ESL) “experts” negotiated their professional identities as they translated what they learned about multicultural competence, second language acquisition, and teaching ESL into turnaround training sessions for their colleagues.
Intensive English Programs in the United States: An Overview of Structure and Mentoring
Authors: Thompson Amy S.
Published: November 2012

Although English as a second language (ESL) programs are common in the United States, there is surprisingly little research documenting the existing structures and mentoring strategies they use. This lack of research could be partly due to ESL programs' widely varying internal structures (Larson, 1990) and the fact that they are often marginalized by the university academic system (see, e.g., Carkin, 1997; Case, 1998; Kaplan, 1997; Vandrick, 1994), which leaves many programs “homeless” and without the support of university‐wide mentoring systems. This article is an overview of the structures and mentoring strategies found in ESL programs throughout the United States. A questionnaire was distributed electronically to the 67 accredited university ESL programs found on the University and College Intensive English Programs website, with 20 of the questionnaires returned. One surprising result was the relatively low number of teaching assistants employed by ESL programs. Although all of the programs surveyed offered some sort of professional development, there was a dearth of a formal mentoring structure within most of the ESL programs.
Ethics and geoengineering: reviewing the moral issues raised by solar radiation management and carbon dioxide removal
Authors: Preston Christopher J.
Published: November 2012

After two decades of failure by the international community to respond adequately to the threat of global climate change, discussions of the possibility of geoengineering a cooler climate have recently proliferated. Alongside the considerable optimism that these technologies have generated, there has also been wide acknowledgement of significant ethical concerns. Ethicists, social scientists, and experts in governance have begun the work of addressing these concerns. The plethora of ethical issues raised by geoengineering creates challenges for those who wish to survey them. The issues are here separated out according to the temporal spaces in which they first arise. Some crop up when merely contemplating the prospect of geoengineering. Others appear as research gets underway. Another set of issues attend the actual implementation of the technologies. A further set occurs when planning for the cessation of climate engineering. Two cautions about this organizational schema are in order. First, even if the issues first arise in the temporal spaces identified, they do not stay completely contained within them. A good reason to object to the prospect of geoengineering, for example, will likely remain a good reason to object to its implementation. Second, the ethical concerns intensify or weaken depending on the technology under consideration. The wide range of geoengineering technologies currently being discussed makes it prudent that each technique should be evaluated individually for its ethical merit. WIREs Clim Change 2013, 4:23–37. doi: 10.1002/wcc.198

This article is categorized under:

Climate, Nature, and Ethics > Ethics and Climate Change
Representing climate change in museum space and places
Authors: Cameron Fiona , Hodge Bob , Salazar Juan Francisco
Published: November 2012

Museums and science centers hold a unique position in the media and political landscape as trusted information sources and are emerging as key players in climate change debates. The modes of engagement with audiences, visitors, and publics allow museums to provide sensorial and affective experiences though the agency of objects and immersive environments, which facilitate an active role on the part of audiences in cocreating narratives around climate change. This article draws on the research findings of an Australian Research Council Linkage project, Hot Science, Global Citizens: the agency of the museum sector in climate change interventions. Hot Science was an international, interdisciplinary project that interrogated the roles of museums and science centers in climate change as places to provide information, activate and broker discussions, and decisions around climate change issues, locally and transnationally. We put forward nine propositions, distilled from the project research findings and the sector‐wide views presented during a symposium held in 2011. We use these propositions to look critically at the ways in which climate change challenges the established concepts and practices of museums and science centers as places of influence, relevance, and certainty in an uncertain world. This includes, for example, the way science is produced, represented, and communicated. Recognizing the complexity and multiscalar nature of climate change entails building more effective responses that translate into action. The big task of the museum sector is not only to inform publics on the science of climate change but also to equip citizens with tactical knowledges that enable participation in actions and debates on climate change that affect their futures. WIREs Clim Change 2013, 4:9–21. doi: 10.1002/wcc.200

This article is categorized under:

Perceptions, Behavior, and Communication of Climate Change > Communication

Social Status of Climate Change Knowledge > Knowledge and Practice

Trans‐Disciplinary Perspectives > Humanities and the Creative Arts
Epigenetic mechanisms in learning and memory
Authors: Blaze Jennifer , Roth Tania L.
Published: November 2012

Recent discoveries have associated epigenetic mechanisms, including DNA methylation, histone modifications, and microRNA (miRNA) processing, with activity‐dependent changes in gene expression necessary to drive long‐term memory formation. Here, we discuss the current interpretation of epigenetic mechanisms in the context of memory and sustained behavioral change. One of the two emerging viewpoints is that epigenetic mechanisms subserve information storage in the central nervous system (CNS), a notion supported by rodent studies of fear, recognition and spatial memories, and stress. The second viewpoint is that epigenetics serves as a mechanism for passing on acquired information across generations, a provocative notion now supported by several lines of work using developing and adult rodents. Continued research on such mechanisms promises to advance our understanding of biological pathways linking experiences to long‐term and even multigenerational trajectories in neurobiology and behavior. WIREs Cogn Sci 2013, 4:105–115. doi: 10.1002/wcs.1205

This article is categorized under:

Neuroscience > Behavior
Fumarylacetoacetate inhibits the initial step of the base excision repair pathway: implication for the pathogenesis of tyrosinemia type I
Authors: Bliksrud Yngve T. , Ellingsen Amund , Bjørås Magnar
Published: November 2012

Hereditary tyrosinemia type I (HT1) is an autosomal recessive disease caused by a deficiency in human fumarylacetoacetate (FAA) hydrolase (FAH), which is the last enzyme in the catabolic pathway of tyrosine. Several reports suggest that intracellular accumulation of intermediates of tyrosine catabolism, such as FAA and succinylacetone (SA) is important for the pathogenesis in liver and kidney of HT1 patients. In this work, we examined the effect of FAA and SA on DNA glycosylases initiating base excision repair (BER), which is the most important pathway for removing mutagenic DNA base lesions. In vitro assays monitoring DNA glycosylase activities demonstrated that FAA but not SA inhibited base removal. In particular, the Neil1 and Neil2 DNA glycosylases were strongly inhibited, whereas inhibition of Nth1 and Ogg1 were less efficient. These DNA glycosylases initiate excision of a broad range of mutagenic oxidative base lesions. Further, FAA showed a modest inhibitory effect on the activity of the alkylbase DNA glycosylase Aag and no significant inhibition of the uracil DNA glycosylase Ung2. These data indicate that FAA inhibition of DNA glycosylases removing oxidative base lesions in HT1 patients may increase mutagenesis, suggesting an important mechanism for development of hepatocarcinoma and somatic mosaicism.
Characteristics of Emergency Department Transfers for Hand Surgery Consultation
Authors: Bauer Andrea S. , Blazar Philip E. , Earp Brandon E. , Louie Dexter L. , Pallin Daniel J.
Published: November 2012

Background

The purpose of this study was to establish the characteristics of patients who are transferred from referring emergency departments (EDs) to two receiving institutions for hand-related emergencies. Our primary hypothesis was that many transferred patients would not require emergent specialty intervention. Our secondary hypotheses were that treatment would differ by day of presentation and type of insurance coverage.

Methods

We searched ED records for all hand-related cases over 1 year. We reviewed charts for demographics and treatment details. The main outcome measures were whether patients were seen by a hand surgeon or underwent surgery within 24 h of transfer.

Results

The study group comprised 296 patients. Ninety-two percent saw a specialty resident, and 48 % saw a hand surgeon. Thirty-nine percent of patients were taken to the operating room within 24 h of presentation. Of patients transferred on the weekends, 48 % saw a hand surgeon versus 61 % of those transferred on weekdays. Similarly, 51 % of patients transferred on a weekday were taken to the OR within 24 h, while 38 % of patients transferred on a weekend were taken to the OR in the same time frame.

Conclusions

More than half of transfers for hand emergencies did not result in examination by a hand surgeon, and nearly two thirds did not require a visit to the OR within 24 h. Patients transferred on the weekend were less likely to see a hand surgeon than those transferred on weekdays. Alternative methods of consultation might allow avoidance of transfer.
Polyol‐Derived Alkoxide/Hydroxide Base Catalysts II: Transesterification Reactions
Authors: Gok Hwee Yoong Felicia , Emami Shahram , Shen Jianhneg , Reaney Martin J. T.
Published: November 2012

Biodiesel, fatty acid methyl ester (FAME), was produced by transesterification of canola oil with methanol in the presence of a series of alkoxide/hydroxide base catalysts produced from glycerol, 1,2‐propanediol, 1,3‐propanediol, xylitol, or sorbitol produced by dehydration reaction of sodium hydroxide in the presence of polyols. Transesterification reactions proceeded efficiently in the presence of sodium alkoxide catalysts prepared at three different mole ratios of sodium hydroxide to glycerol (1:1, 2:1, and 3:1). The production of methyl ester during the course of the reaction was determined repeatedly and the reaction progress was compared with that achieved in a reaction catalyzed by freshly prepared anhydrous sodium methoxide as a standard catalyst. Sodium alkoxide/hydroxide catalysts activity during the first 2 min of the reaction was in the order of: sorbitol < xylitol < sodium methoxide < 1,2‐propanediol < 1,3‐propanediol < glycerol regardless of the mole ratio of sodium hydroxide to glycerol. All catalysts showed a higher methyl ester accumulation at higher ratios of sodium hydroxide to polyol and had the following order 1:1 < 2:1 < 3:1 (sodium hydroxide:glycerol). Several of these catalysts were as powerful as sodium methoxide in catalyzing the transesterification reaction at the same mole concentration. All alkoxide/hydroxide catalysts resulted in a high FAME accumulation (>95 wt%) in a single transesterification batch reaction.