bluuebunny/crossref_metadata_2025 huggingface dataset:
Polysulfones with Phenylalanine Derivatives as Chiral Selectors – Membranes for Chiral Separation
Authors: Isezaki Jun , Yoshikawa Masakazu , Li Nanwen , Robertson Gilles P. , Guiver Michael D.
Published: October 2012

Polysulfone with a derivative of phenylalanyl residue as a chiral selector (PSf-Ac-D-Phe or PSf-Ac-L-Phe) were prepared by polymer reaction of benzylamine-modified polysulfones with N-a-acetyl-D-phenylalanine or N-a-acetyl-L-phenylalanine. Both polysulfones having a chiral selector gave durable self-standing membranes. The specific rotations of those polymers revealed that the chiral selectors were successfully introduced into the polysulfone. PSf-Ac-D-Phe membrane incorporated L-Glu in preference to D-Glu and vice versa. The chiral separation ability was studied by applying a concentration gradient as a driving force for membrane transport. Permselectivities for those two types of membrane reflected their adsorption selectivities. PSf-Ac-D-Phe membrane selectively transported L-Glu and vice versa. Predicted permselectivities by adopting membrane resistance coincided with the observed ones.
Preparation of a Modified Octadecyl Silica Membrane Disk for Solid Phase Extraction of Lead(II) Ions in Different Real Samples and their Determination with ICP-AES
Authors: Pourjavid Mohammad Reza , Sehat Ali Akbari
Published: October 2012

A solid phase extraction and inductively coupled plasma atomic emission spectrometry (ICP-AES) for the determination of lead(II) ions with octadecyl-bonded silica membrane disks modified by 4-methyl-N-{2-(4-methylbenzothioyl)aminoethyl}benzenecarbothioamide (MMAB) was studied. Extraction efficiency, and the effects of parameters such as flow rate, pH, type and the least amount of acid for stripping of lead(II) from the modified disks and break through volume were examined. The maximum capacity of the membrane disks modified by 4.0 mg of MMAB used was found to be 527 ± 4 µg of lead(II) ions. The preconcentration factor is 440 (for 2200 mL water sample and flow rate of 12 mL min-1) and detection limit of the proposed method is 85.4 ng mL-1. The developed method was successfully applied to the determination of lead(II) ions in blood, spinach, bean, hair, milk, pepper and various water samples.
Mathematical Modeling of CO2/CH4 Separation by Hollow Fiber Membrane Module Using Finite Difference Method
Authors: Shamsabadi Ahmad Arabi , Kargari Ali , Farshadpour Foroogh , Laki Saeed
Published: October 2012

Removal of CO2 in landfill gas recovery processes and fractured wells as well as its application in enhanced oil recovery and its environmental aspects are of interest. Also separation of CO2 from CH4 in Ethylene Oxide plant is an environmental policy of Marun Petrochemical Company. In the present work, a shell-fed hollow fiber module was modeled mathematically for CO2 separation from CH4. Finite difference method was used for solving the equations. Comparison between co-current and counter-current flow patterns showed that for all conditions, counter current pattern had better efficiency for CO2/CH4 separation. Influence of operating parameters such as feed pressure, permeate pressure, feed flow rate, fiber length and CO2 concentration of feed on separation efficiency of CO2/CH4 mixture was investigated. Also the effect of feed and permeate pressures on required membrane area showed that the membrane area increases by increasing permeate pressure and decreases by increasing feed pressure. The modeling offers valuable data about feasibility study and economical evaluation of a gas separation unit operation as a helpful unit in the industry.
Full-Factorial Experimental Design to Determine the Impacts of Influential Parameters on the Porosity and Mechanical Strength of LLDEP Microporous Membrane Fabricated via Thermally Induced Phase Separation Method
Authors: Shokri Elham , Yegani Reza
Published: October 2012

Membrane separation processes have a wide application in liquid and gas purification industries. They enjoy advantages such as convenient processibility, easy and lower production and operational costs. Thermally induced phase separation (TIPS) process, due to its wide advantages, has won special attention in recent decades. In this process, a homogenous solution of polymer-diluent at a temperature above the polymer melting point is formed and the solution is then cast in the favorite shape. In order to create a porous structure, the diluent is extracted. In this work, microporous LLDPE membrane is fabricated and full factorial experimental design is used to evaluate the individual as well as mutual impacts of polymer concentration, membrane thickness and cooling bath temperature on the porosity and mechanical strength of the membrane. The results obtained from the analysis of variance of membrane porosity and mechanical strength, showed that the impact of cooling bath temperature is much more important than polymer concentration and membrane thickness. Higher cooling bath temperature, lower polymer concentration and membrane thickness result in higher porosity.
Analyse des pratiques d’enseignement
Authors: Clanet Joël , Talbot Laurent
Published: October 2012

La présente contribution traite de la nécessité d’étudier les pratiques d’enseignement à partir du constat de ce qu’elles sont au-delà de ce qu’elles devraient être. Cette tâche dévolue aux chercheurs en sciences de l’éducation vise à mieux connaître les pratiques d’enseignement dans leurs relations aux apprentissages des élèves afin de constituer la base de données utiles aux formateurs d’enseignants et nécessaire à toute réflexivité des enseignants à propos de leur propre pratique. Les notions de compétence, de schème et d’instrument sont utiles à cette entreprise d’explication et de compréhension des pratiques. La proposition de cadrage théorique est illustrée par une mise en perspective des pratiques d’enseignement de professeurs des écoles et de collèges. Celles-ci se distinguent sur bien des aspects, ce qui réclame la mise à l’épreuve de nouvelles hypothèses explicatives.
L’efficacité des pratiques d’enseignement au travers des rapports d’inspection
Authors: Marcel Jean-François , Veyrac Hélène
Published: October 2012

Les inspections pédagogiques sont ici un moyen d’approcher « l’efficacité institutionnelle » des dispositifs d’enseignement-apprentissage. L’analyse de 38 rapports d’inspection d’enseignants en lycées agricoles français met en évidence les dimensions des pratiques enseignantes qui y sont convoquées. L’analyse de treize rapports d’inspection défavorables au maintien de l’enseignant dans le métier contribue à expliciter le référent des pratiques lors d’évaluation. Ces analyses aboutissent à une modélisation des pratiques d’enseignement. Elles montrent que les évaluations portent davantage sur les pratiques d’enseignement que sur l’apprentissage des élèves, davantage sur les moyens mis en oeuvre pour enseigner que sur le processus d’enseignement-apprentissage.
Le discours identitaire d’enseignants du secondaire : entre la crise et la nécessité de donner du sens à l’expérience
Authors: Martineau Stéphane , Presseau Annie
Published: October 2012

Cet article présente les résultats d’une recherche menée auprès d’enseignants du niveau secondaire au Québec, plus spécifiquement dans la région de la Mauricie. Les auteurs proposent une réflexion sur la construction de l’identité professionnelle dans un contexte de crise des institutions. Ils soutiennent que dans ce contexte l’enseignant ne peut compter sur des cadres sociaux stables et solides pour se constituer une identité professionnelle et que c’est l’expérience au travail qui devient le matériau primordial à partir duquel s’élabore cette identité. Par conséquent, l’enseignant a à construire son identité à partir d’une mise en récit rationnelle de son expérience de la pratique professionnelle.
Les compétences professionnelles des enseignants : étude d’un référentiel officiel et conséquences pour l’étude des pratiques enseignantes
Authors: Rey Bernard
Published: October 2012

Afin de contribuer à préciser la notion de « pratique enseignante », le présent article analyse un référentiel de compétences professionnelles de l’enseignant. Il examine ensuite la manière dont deux groupes de formateurs d’enseignants tentent d’utiliser ce référentiel pour évaluer deux séances d’enseignement (une au secondaire et une autre au primaire). Les analyses révèlent la difficulté à évaluer une séance à partir d’éléments déterminés a priori dans une liste de compétences. L’évaluation d’une séance d’enseignement semble requérir la prise en compte de sa totalité organique.
Lashing Out after Stewing over Public Insults: The Effects of Public Provocation, Provocation Intensity, and Rumination on Triggered Displaced Aggression
Authors: Vasquez Eduardo A. , Pedersen William C. , Bushman Brad J. , Kelley Nicholas J. , Demeestere Philippine , Miller Norman
Published: October 2012

Four studies present the first evidence showing that public (vs. private) provocation augments triggered displaced aggression by increasing the perceived intensity of the provocation. This effect is shown to be independent of face‐saving motivation. Following a public or private provocation, Study 1 participants were induced to ruminate or were distracted for 20 min. They then had an opportunity to aggress against another person who either acted in a neutral or mildly annoying fashion (viz. triggering event). As expected, the magnitude of the greater displaced aggression of those who ruminated before the triggering event compared with those distracted was greater under public than private provocation. Study 2 replicated the findings of Study 1 and confirmed that public provocations are experienced as more intense. Studies 3 and 4 both manipulated provocation intensity directly to show that it mediated the moderating effect of public/private provocation found in Study 1. The greater intensity of a public provocation increases reactivity to a subsequent trigger, which in turn, augments triggered displaced aggression. Aggr. Behav. 39:13‐29, 2013. © 2012 Wiley Periodicals, Inc.
Steric Effects on the Stereochemistry of Old Yellow Enzyme‐Mediated Reductions of Unsaturated Diesters: Flipping of the Substrate within the Enzyme Active Site Induced by Structural Modifications
Authors: Brenna Elisabetta , Gatti Francesco G. , Manfredi Alessia , Monti Daniela , Parmeggiani Fabio
Published: October 2012

The ene‐reductase‐mediated reduction of the carbon‐carbon double bond of some alkyl 2‐substituted butenedioates was investigated. The stereochemical outcome of the reaction was found to be influenced by steric effects. Ethyl and butyl citraconates were converted into the corresponding alkyl (R)‐2‐methylsuccinates with excellent enantioselectivity, whereas ethyl and butyl mesaconates were completely unreactive. Methyl 2‐substituted fumarates were reduced to enantiomerically enriched methyl (S)‐2‐substituted succinates, whereas the (Z)‐stereoisomers were left unreacted by ene‐reductases. Labelling experiments were performed to investigate the mechanism of these bioreductions and explain their stereochemical outcome.
Neuropeptide Y‐immunoreactive Neurons in the Cerebral Cortex of Humans and Other Haplorrhine Primates
Authors: RAGHANTI MARY ANN , CONLEY TIFFINI , SUDDUTH JESSICA , ERWIN JOSEPH M. , STIMPSON CHERYL D. , HOF PATRICK R. , SHERWOOD CHET C.
Published: October 2012

We examined the distribution of neurons immunoreactive for neuropeptide Y (NPY) in the posterior part of the superior temporal cortex (Brodmann's area 22 or area Tpt) of humans and nonhuman haplorrhine primates. NPY has been implicated in learning and memory and the density of NPY‐expressing cortical neurons and axons is reduced in depression, bipolar disorder, schizophrenia, and Alzheimer's disease. Due to the role that NPY plays in both cognition and neurodegenerative diseases, we tested the hypothesis that the density of cortical and interstitial neurons expressing NPY was increased in humans relative to other primate species. The study sample included great apes (chimpanzee and gorilla), Old World monkeys (pigtailed macaque, moor macaque, and baboon) and New World monkeys (squirrel monkey and capuchin). Stereologic methods were used to estimate the density of NPY‐immunoreactive (‐ir) neurons in layers I‐VI of area Tpt and the subjacent white matter. Adjacent Nissl‐stained sections were used to calculate local densities of all neurons. The ratio of NPY‐ir neurons to total neurons within area Tpt and the total density of NPY‐ir neurons within the white matter were compared among species. Overall, NPY‐ir neurons represented only an average of 0.006% of the total neuron population. While there were significant differences among species, phylogenetic trends in NPY‐ir neuron distributions were not observed and humans did not differ from other primates. However, variation among species warrants further investigation into the distribution of this neuromodulator system. Am. J. Primatol. 75:415‐424, 2013. © 2012 Wiley Periodicals, Inc.
The Species Concept as a Cognitive Tool for Biological Anthropology
Authors: BRUNER EMILIANO
Published: October 2012

Taxonomy is caught between the search for the “perfect” theory and an elusive biological variability. The lack of major advances in issues related to how “species” and other taxonomic categories are defined suggests that perhaps we should avoid excessively rigid formalism in this regard. The risk is a separation between elegant but useless theories and confusing applications of the taxonomic tools. Communication is one of the main functions of taxonomy, and stability one of the main parameters that taxonomy users should be sensitive to. An excess of stability may generate anachronistic consequences while continuous revisions may make the tool of taxonomy scarcely practical. The current tendency pushes toward more and more fragmentation of biologically valid taxa. While taxonomy specialists enjoy such challenges, many taxonomy users feel a bit nervous and discouraged when trying to use a tool that is constantly changing. Debates over taxonomy would seem particularly unrewarding for fields with limited samples and scarce biological diversity, such as palaeoanthropology. In this context, where the information available is rarely sufficient to supply consistent taxonomical evidence, there are frequently excessive efforts to create debate on species separations. The risk is that we maintain the debate on a purely theoretical level, or else we distrust a reliable use of taxonomy. A compromise (and recommended) choice between these two extremes would be to rely on shared and reasonable interpretations of homogeneous evolutionary units, without diving into fine‐grained issues that will remain, however, unresolved. Taxonomy should be a tool, not the goal, of the evolutionary biologist. Our mind needs discrete and recognizable objects to structure our perception of reality. There is no reason to expect that nature works the same way. Am. J. Primatol. 75:10‐15, 2013. © 2012 Wiley Periodicals, Inc.
A Chemodosimetric Probe Based on a Conjugated Oxidized Bis‐Indolyl System for Selective Naked‐Eye Sensing of Cyanide Ions in Water
Authors: Kumari Namita , Jha Satadru , Bhattacharya Santanu
Published: October 2012

A new bis‐indolyl‐based colorimetric probe has been synthesized. This allows a Michael‐type adduct formation for the detection of cyanide ions. The probe shows a remarkable color change from red to colorless upon addition of the cyanide ions in pure water. The cyanide ion reacts with the probe and removes the conjugation of the bis‐indolyl moiety of the probe with that of the 4‐substituted aromatic ring. This renders the probe colorless. The mechanism of the reaction of the probe with the cyanide ion was established by using 1H and 13C NMR spectroscopy, mass spectrometry, and kinetic studies.
Advances in the Cross‐Linguistic Study of Ideophones
Authors: Dingemanse Mark
Published: October 2012

Ideophones are marked words that depict sensory imagery found in many of the world’s languages. They are noted for their special forms, distinct grammatical behaviour, rich sensory meanings, and interactional uses related to experience and evidentiality. This review surveys recent developments in ideophone research. Work on the semiotics of ideophones helps explain why they are marked and how they realise the depictive potential of speech. A true semantic typology of ideophone systems is coming within reach through a combination of language‐internal analyses and language‐independent elicitation tools. Documentation of ideophones in a wide variety of genres as well as sequential analysis of ideophone use in natural discourse leads to new insights about their interactional uses and about their relation to other linguistic devices like reported speech and grammatical evidentials. As the study of ideophones is coming of age, it sheds new light on what is possible and probable in human language.
Vector Space Models of Word Meaning and Phrase Meaning: A Survey
Authors: Erk Katrin
Published: October 2012

Distributional models represent a word through the contexts in which it has been observed. They can be used to predict similarity in meaning, based on the distributional hypothesis, which states that two words that occur in similar contexts tend to have similar meanings. Distributional approaches are often implemented in vector space models. They represent a word as a point in high‐dimensional space, where each dimension stands for a context item, and a word's coordinates represent its context counts. Occurrence in similar contexts then means proximity in space. In this survey we look at the use of vector space models to describe the meaning of words and phrases: the phenomena that vector space models address, and the techniques that they use to do so. Many word meaning phenomena can be described in terms of semantic similarity: synonymy, priming, categorization, and the typicality of a predicate's arguments. But vector space models can do more than just predict semantic similarity. They are a very flexible tool, because they can make use of all of linear algebra, with all its data structures and operations. The dimensions of a vector space can stand for many things: context words, or non‐linguistic context like images, or properties of a concept. And vector space models can use matrices or higher‐order arrays instead of vectors for representing more complex relationships. Polysemy is a tough problem for distributional approaches, as a representation that is learned from all of a word's contexts will conflate the different senses of the word. It can be addressed, using either clustering or vector combination techniques. Finally, we look at vector space models for phrases, which are usually constructed by combining word vectors. Vector space models for phrases can predict phrase similarity, and some argue that they can form the basis for a general‐purpose representation framework for natural language semantics.
Human Elastin‐Based Recombinant Biopolymers Improve Mesenchymal Stem Cell Differentiation
Authors: Çelebi Betül , Cloutier Maxime , Balloni Rodrigo , Mantovani Diego , Bandiera Antonella
Published: October 2012

Elastin‐based polypeptides are a class of smart biopolymers representing an important model in the design of biomaterials. The combination of biomimetic materials with cells that have great plasticity provides a promising strategy for the realization of highly engineered cell‐based constructs for regenerative medicine and tissue repair applications. Two recombinant biopolymers inspired by human elastin are assessed as coating agents to prepare biomimetic surfaces for cell culture. These substrates are assayed for hBM MSC culture. The coated surfaces are also characterized with AFM to evaluate the topographical features of the deposited biopolymers. The results suggest that the elastin‐derived biomimetic surfaces play a stimulatory role on osteogenic differentiation of MSCs.

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Comb‐Shaped Glycopolymer/Peptide Bioconjugates by Combination of RAFT Polymerization and Thiol‐Ene “Click” Chemistry
Authors: Wang Xiaobei , Liu Li , Luo Yan , Shi Haiting , Li Jingyi , Zhao Hanying
Published: October 2012

Comb‐shaped glycopolymer/peptide bioconjugates are constructed by grafting reduced glutathione (GSH) onto acrylate‐functional block glycocopolymers via thiol‐ene click chemistry. In aqueous solution, the glycopolymer/GSH bioconjugate self‐assembles to sugar‐installed spherical micelles. The size of micelles decreases with increasing pH, demonstrating pH‐responsive character. The isoelectric point (IEP) of the PMAGlc/GSH bioconjugate is estimated to be 3.43. The micelles show a specific interaction with the protein Concanavalin A. At endosomal pH, the PMAGlc/GSH bioconjugate can gradually degrade. These pH‐responsive glycopolymer/peptide micelles with biological recognition and degradation can be used as multifunctional nanocarriers for targeted drug delivery.

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Thermoplastic Poly(urethane urea)s From Novel, Bio‐based Amorphous Polyester Diols
Authors: Tang Donglin , Noordover Bart A. J. , Sablong Rafael J. , Koning C. E.
Published: October 2012

In this study, two novel, bio‐based, amorphous polyester diols, namely poly(1,2‐dimethylethylene adipate) (PDMEA) and poly(1,2‐dimethylethylene succinate) (PDMES) are used to prepare thermoplastic poly(urethane urea)s (TPUUs). Interestingly, the TPUUs based on PDMEA show similar thermal and mechanical properties as their counterparts based on poly(1,2‐propylene glycol). By decreasing the hard segment length, the flow temperature (Tfl) of the TPUUs decreases. The Tfl values of the 3U series are around 170 °C, which is below their degradation temperatures. The methyl groups adjacent to the ester groups in PDMEA and PDMES may hinder the hydrolysis of the polyester soft segments in the TPUUs.
3D isotropic high‐resolution diffusion‐weighted MRI of the whole brain with a motion‐corrected steady‐state free precession sequence
Authors: O'Halloran R. L. , Aksoy M. , Van A. T. , Bammer R.
Published: October 2012

The main obstacle to high‐resolution (<1.5 mm isotropic) 3D diffusion‐weighted MRI is the differential motion‐induced phase error from shot‐to‐shot. In this work, the phase error is addressed with a hybrid 3D navigator approach that corrects motion‐induced phase in two ways. In the first, rigid‐body motion is corrected for every shot. In the second, repeatable nonrigid‐body pulsation is corrected for each portion of the cardiac cycle. These phase error corrections were implemented with a 3D diffusion‐weighted steady‐ state free precession pulse sequence and were shown to mitigate signal dropouts caused by shot‐to‐shot phase inconsistencies compared to a standard gridding reconstruction in healthy volunteers. The proposed approach resulted in diffusion contrast more similar to the contrast observed in the reference echo‐planer imaging scans than reconstruction of the same data without correction. Fractional anisotropy and Color fractional anisotropy maps generated with phase‐corrected data were also shown to be more similar to echo‐planer imaging reference scans than those generated without phase correction. Magn Reson Med 70:466–478, 2013. © 2012 Wiley Periodicals, Inc.
Efficient energy transfer between amphiphilic dendrimers with oligo(p‐phenylenevinylene) core branches and oligo(ethylene oxide) termini in micelles
Authors: Wook Chang Dong , Bae Seo‐Yoon , Dai Liming , Baek Jong‐Beom
Published: October 2012

The efficient fluorescence resonance energy transfer (FRET) between amphiphilic dendrimers with oligo(p‐phenylenevinylene) core branches and oligo(ethylene oxide) termini have been observed in micelles. All dendrimers show the critical micelle concentration and lower critical solution temperature as well as fluorescent emission. Tailoring electronic structures of the conjugated amphiphiles for FRET have been conveniently achieved by varying the branch number and/or the conjugated core structure. The Stern‐Volmer constants (KSV) for FRET were found to be 4.51 × 10−5 and 8.78 × 10−5 M for Den 30–40 and Den 50–40, respectively. The effects external stimuli such as solvent and temperature on FRET have been also investigated. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013
On modifying properties of polymeric melts by nanoscopic particles
Authors: Atilgan Canan , Inanc Ibrahim , Rana Atilgan Ali
Published: October 2012

We study geometric and energetic factors that partake in modifying properties of polymeric melts via inserting well‐dispersed nanoscopic particles (NP). Model systems are cis‐1,4‐polybutadiene melts including a single atomic clusters of size varied in the range 10–150 atoms (3–7 Å in radius; 0.1–1.5% v/v). We modify the interactions between the chains and the particle by tuning attractive van der Waals interactions. Using molecular dynamics, we study equilibrium fluctuations and dynamical properties at the interface. The NPs move in the polymer matrix in two different regimes corresponding to trapped and free diffusion, depending on the NP size. Furthermore, degree of crowding around the NP by the polymer chains is quantified. Effect of NP size and interaction strength both on volume and volumetric fluctuations is manifested in mechanical properties, quantified here by bulk modulus, K. Tuning NP size and nonbonded interactions results in ∼15% enhancement in K by addition of a maximum of 1.5% v/v NP. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Enhancing fire risk evaluations of plant structures using finite element analysis
Authors: Reed Morgan , Peterson Eric
Published: October 2012

Advanced software can be used to enhance risk evaluations with fire and explosion simulations concerning the survivability of offshore drilling structures as well as major plant structures. This article focuses on simulated heat loads from fires showing structural responses due to thermal radiation fluxes, associated applied mechanical loads, and different fire protection features.

Early simulation of fires (fires and their actual region of impact) allow for effective fire safety measures to be incorporated into the structure, for example, adding better passive fire protection measures where needed or substituting heavy steel with lighter alloys where local fire consequences are less severe.

This article shows how three computer programs are utilized for optimizing the engineering design of structures, for example, offshore platforms, floating storage and offloading vessels, office buildings. This type of evaluation can produce significant cost savings by simulating realistic fire scenarios based on fundamental engineering principles and local conditions. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012
What risk reduction measures should be credited in process hazard analysis?
Authors: Baybutt Paul
Published: October 2012

Process hazard analysis (PHA) identifies existing risk reduction measures so that their contribution to reducing risk can be determined in order to decide if the risk of hazard scenarios is tolerable. Unfortunately, PHA practitioners do not follow consistent practices in crediting risk reduction measures as there are no generally accepted standards or guidelines for doing so. This situation leads to inconsistent studies and possibly erroneous results. The meaning of risk reduction measures and their relationship to process safeguards are discussed in this article, and risk reduction measures that could be credited in PHA are identified. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012.
An Investigation of Working Memory Effects on Oral Grammatical Accuracy and Fluency in Producing Questions in English
Authors: Wright Clare
Published: October 2012

This article addresses the question of how far working memory may affect second language (L2) learners' improvement in spoken language during a period of immersion. Research is presented testing the hypothesis that individual differences in working memory (WM) capacity are associated with individual variation in improvements in oral production of questions in English. Thirty‐two Chinese adult speakers of English were tested, before and after a year's postgraduate study in the United Kingdom, to measure grammatical accuracy and fluency using a question elicitation task, and to measure WM using a battery of first language (L1) and L2 WM tests. Story recall in L1 (Mandarin) was significantly associated with individuals' improvement in oral grammatical measures (p < .05). However, there was no significant mean improvement across the cohort in grammatical accuracy, although there was for fluency. The findings suggest that WM may aid certain aspects of individuals' L2 oral proficiency during academic immersion through postgraduate study. They also indicate that academic immersion in itself can lead to improvements in oral proficiency, independent of WM capacity, but there is no general guarantee of significant grammatical change. Further research to clarify the opportunities for input and interaction available in academic immersion settings is called for.
Enzymatic Interesterification Between Pine Seed Oil and a Hydrogenated Fat to Prepare Semi‐Solid Fats Rich in Pinolenic Acid and Other Polyunsaturated Fatty Acids
Authors: Otero Cristina , Márquez Pablo , Criado Manuel , Hernández‐Martín Estela
Published: October 2012

Enzyme catalyzed interesterification (EIE) of pine seed oil (PSO) and a fully hydrogenated soybean oil (FHSBO) were studied in batch reactors in solvent‐free media to prepare different semisolid fats rich in polyunsaturated fatty acids (PUFA). Optimal operation conditions found were: 10 % (w/w) enzyme loading, 75 °C and magnetic agitation at 300 rpm. Quasi‐equilibrium conditions were reached after 2, 3 and 6 h, when immobilized lipases from Thermomyces lanuginosus (Lipozyme® TL IM),Candida antarctica B. (Novozym® 435) and Rhizomucor miehei (Lipozyme® RM IM) from Novozymes A/S (Bagsvaerd, Denmark) were employed, respectively. Similar distributions of unsaturated to saturated fatty acid (UFA/SFA) residues along the glycerol backbone of the fat products were obtained with both non‐selective and sn‐1(3) regioselective lipases due to significant spontaneous acyl migration during the reaction. The products had higher UFA/SFA ratios at the sn‐2 position (2.4–2.5, 1.4–1.7, and 0.5–0.8 for the trials involving 20, 40 and 70 % FHSBO, w/w, respectively) than the corresponding physical blends (0.8, 0.4 and 0.5, respectively). Fat products containing 3.1–11.6 % (w/w) pinolenic acid (Pn) and 16.1–35.7 % (w/w) linoleic acid (L) at the sn‐2 position were prepared. The free acid contents of EIE products prepared with Lipozyme® TL IM and Novozym® 435 were 6.1–6.4 and 2.5–2.6, respectively. Residual activities of Lipozyme® TL IM and Novozym® 435 diminish by ca. 20 % after 9 reaction cycles.
State Control over Private Military and Security Companies in Armed Conflict
Authors: Tonkin Hannah
Published: October 2012

The past two decades have witnessed the rapid proliferation of private military and security companies (PMSCs) in armed conflicts around the world, with PMSCs participating in, for example, offensive combat, prisoner interrogation and the provision of advice and training. The extensive outsourcing of military and security activities has challenged conventional conceptions of the state as the primary holder of coercive power and raised concerns about the reduction in state control over the use of violence. Hannah Tonkin critically analyses the international obligations on three key states - the hiring state, the home state and the host state of a PMSC - and identifies the circumstances in which PMSC misconduct may give rise to state responsibility. This analysis will facilitate the assessment of state responsibility in cases of PMSC misconduct and set standards to guide states in developing their domestic laws and policies on private security.
Direct numerical simulation of a spatially developing compressible plane mixing layer: flow structures and mean flow properties
Authors: Zhou Qiang , He Feng , Shen M. Y.
Published: October 2012

The spatially developing compressible plane mixing layer with a convective Mach number of 0.7 is investigated by direct numerical simulation. A pair of equal and opposite oblique instability waves is introduced to perturb the mixing layer at the inlet. The full evolution process of instability, including formation of $ \mrm{\Lambda} $-vortices and hairpin vortices, breakdown of large structures and establishment of self-similar turbulence, is presented clearly in the simulation. In the transition process, the flow fields are populated sequentially by $ \mrm{\Lambda} $-vortices, hairpin vortices and ‘flower’ structures. This is the first direct evidence showing the dominance of these structures in the spatially developing mixing layer. Hairpin vortices are found to play an important role in the breakdown of the flow. The legs of hairpin vortices first evolve into sheaths with intense vorticity then break up into small slender vortices. The later flower structures are produced by the instability of the heads of the hairpin vortices. They prevail for a long distance in the mixing layer until the flow starts to settle down into its self-similar state. The preponderance of slender inclined streamwise vortices is observed in the transversal middle zone of the transition region after the breakup of the hairpin legs. This predominance of streamwise vortices also persists in the self-similar turbulent region, though the vortices there are found to be relatively very weak. The evolution of both the mean streamwise velocity profile and the Reynolds stresses is found to have close connection to the behaviour of the large vortex structures. High growth rates of the momentum and vorticity thicknesses are observed in the transition region of the flow. The growth rates in the self-similar turbulence region decay to a value that agrees well with previous experimental and numerical studies. Shocklets occur in the simulation, and their formation mechanisms are elaborated and categorized. This is the first three-dimensional simulation that captures shocklets at this low convective Mach number.
Investigating the transition from central peak to peak‐ring basins using central feature volume measurements from the Global Lunar DTM 100 m
Authors: Bray Veronica J. , Atwood‐Stone Corwin , McEwen Alfred M.
Published: October 2012

Several theories have been suggested to explain the transition from peak to peak‐ring crater morphology. In order to explore the transition and assess the currently advocated peak‐ring formation theories, we have collected measurements of central feature volumes and heights for relatively fresh lunar impact craters. We employed the Global Lunar DTM 100 m, which has the vertical precision and spatial coverage necessary to accurately measure peak and peak‐ring volumes in more craters than previously possible. The similarity in both trend and magnitude of peak and peak‐ring volumes suggests that peak‐ring formation is closely related to the development of central peaks as crater size increases. Our data thus lends support to those peak‐ring formation theories involving peak collapse.
Whistler waves associated with weak interplanetary shocks
Authors: Ramírez Vélez J. C. , Blanco‐Cano X. , Aguilar‐Rodriguez E. , Russell C. T. , Kajdič P. , Jian L. K. , Luhmann J. G.
Published: October 2012

We analyze the properties of 98 weak interplanetary shocks measured by the dual STEREO spacecraft over approximately 3 years during the past solar minimum. We study the occurrence of whistler waves associated with these shocks, which on average are high beta shocks (0.2 < β< 10). We have compared the waves properties upstream and downstream of the shocks. In the upstream region the waves are mainly circularly polarized, and in most of the cases (∼75%) they propagate almost parallel to the ambient magnetic field (<30°). In contrast, the propagation angle with respect to the shock normal varies in a broad range of values (20° to 90°), suggesting that they are not phase standing. We find that the whistler waves can extend up to 100,000 km in the upstream region but in most cases (88%) are contained in a distance within 30,000 km from the shock. This corresponds to a larger region with upstream whistlers associated with IP shocks than previously reported in the literature. The maximum amplitudes of the waves are observed next to the shock interface, and they decrease as the distance to the shock increases. In most cases the wave propagation direction becomes more aligned with the magnetic field as the distance to the shock increases. These two facts suggest that most of the waves in the upstream region are Landau damping as they move away from the shock. From the analysis we also conclude that it is likely that the generation mechanism of the upstream whistler waves is taking place at the shock interface. In the downstream region, the waves are irregularly polarized, and the fluctuations are very compressive; that is, the compressive component of the wave clearly dominates over the transverse one. The majority of waves in the downstream region (95%) propagate at oblique angles with respect to the ambient magnetic field (>60°). The wave propagation with respect to the shock‐normal direction has no preferred direction and varies similarly to the upstream case. It is possible that downstream fluctuations are generated by ion relaxation as suggested in previous hybrid simulation shocks.
Forecasting the number of extreme daily events out to a decade ahead
Authors: Eade Rosie , Hamilton Emily , Smith Doug M. , Graham Richard J. , Scaife Adam A.
Published: October 2012

The predictability of daily temperature and precipitation extremes is assessed out to a decade ahead using the Met Office Decadal Prediction System. Extremes are defined using a simple percentile based counting method applied to daily gridded observation data sets and corresponding model forecasts. We investigate moderate extremes, with a 10% probability of occurrence, ensuring they are frequent enough for robust skill analysis while having sizable impacts. We quantify the predictability of extremes, assess the impact of initialization, and compare with the predictability of the mean climate. We find modest but significant skill for seasonal predictions of temperature extremes in most regions (global area‐average correlation of 0.3) and for precipitation extremes over the USA (area‐average correlation of 0.2). The skill of both temperature and European rainfall extremes improves for multiyear forecast periods, as longer averaging periods reduce the impact of unpredictable short‐term variations, capitalizing on predictable trends from external forcings. For 5 year periods out to a decade ahead, root‐mean square temperature errors are reduced by 20% compared to use of climatology in most regions, apart from the southeastern USA. Initialization improves forecast skill for temperature and precipitation extremes on seasonal timescales in most regions. However, there is little improvement beyond the first year suggesting that skill then arises largely from external forcings. The skill for extremes is generally similar to, but slightly lower than, that for the mean. However, extremes can be more skillful than the mean, for example, USA cold nights, where trends in extremes are greater than for the mean.
Formation of high-molecular-weight angiotensinogen during pregnancy is a result of competing redox reactions with the proform of eosinophil major basic protein
Authors: Kløverpris Søren , Skov Louise L. , Glerup Simon , Pihl Kasper , Christiansen Michael , Oxvig Claus
Published: October 2012

The plasma concentration of the placentally derived proMBP (proform of eosinophil major basic protein) increases in pregnancy, and three different complexes containing proMBP have been isolated from pregnancy plasma and serum: a 2:2 complex with the metalloproteinase, PAPP-A (pregnancy-associated plasma protein-A), a 2:2 complex with AGT (angiotensinogen) and a 2:2:2 complex with AGT and complement C3dg. In the present study we show that during human pregnancy, all of the circulating proMBP exists in covalent complexes, bound to either PAPP-A or AGT. We also show that the proMBP–AGT complex constitutes the major fraction of circulating HMW (high-molecular weight) AGT in late pregnancy, and that this complex is able to further associate with complement C3 derivatives post-sampling. Clearance experiments in mice suggest that complement C3-based complexes are removed faster from the circulation compared to monomeric AGT and the proMBP–AGT complex. Furthermore, we have used recombinant proteins to analyse the formation of the proMBP–PAPP-A and the proMBP–AGT complexes, and we demonstrate that they are competing reactions, depending on the same cysteine residue of proMBP, but differentially on the redox potential, potentially important for the relative amounts of the complexes in vivo. These findings may be important physiologically, since the biochemical properties of the proteins change as a consequence of complex formation.
Current Status of Adult Spinal Deformity
Authors: Youssef J. A. , Orndorff D. O. , Patty C. A. , Scott M. A. , Price H. L. , Hamlin L. F. , Williams T. L. , Uribe J. S. , Deviren V.
Published: October 2012

Purpose

To review the current literature for the nonoperative and operative treatment for adult spinal deformity.

Recent Findings

With more than 11 million baby boomers joining the population of over 60 years of age in the United States, the incidence of lumbar deformity is greatly increasing. Recent literature suggests that a lack of evidence exists to support the effectiveness of nonoperative treatment for adult scoliosis. In regards to operative treatment, current literature reports a varying range of improved clinical outcomes, curve correction, and complication rates. The extension of fusion to S1 compared with L5 and lower thoracic levels compared with L1 remains a highly controversial topic among literature.

Most adult deformity patients never seek nonoperative or operative treatment. Of the few that seek treatment, many can benefit from nonoperative treatment. However, in selected patients who have failed nonoperative treatment and who are candidates for surgical intervention, the literature reflects positive outcomes related to surgical intervention as compared with nonoperative treatment despite varying associated ranges in morbidity and mortality rates. If nonoperative therapy fails in addressing a patient's complaints, then an appropriate surgical procedure that relieves neural compression, corrects excessive sagittal or coronal imbalance, and results in a solidly fused, pain-free spine is warranted.
Interaction of phenol with xenon and nitrogen: Spectroscopic and computational characterization
Authors: Cao Qian , Andrijchenko Natalya , Ahola Anna-Elina , Domanskaya Alexandra , Räsänen Markku , Ermilov Alexander , Nemukhin Alexander , Khriachtchev Leonid
Published: October 2012

Intermolecular complexes of phenol with xenon and nitrogen are studied by infrared absorption spectroscopy in a neon matrix and by quantum chemistry calculations. The π complex is theoretically the most stable 1:1 phenol⋅⋅⋅Xe structure, but it has no characteristic shifts in the calculated vibrational spectrum, which complicates its experimental characterization. However, the formation of the π complex finds indirect but significant support from the experimental results. The calculated spectrum of the less stable H-bonded complex shows a number of characteristic absorptions, but they are not observed in the experiment, indicating the lack of its formation. For the phenol⋅⋅⋅Xen (n = 2–4) complexes, the calculations predict substantial changes in the vibrational spectra, and the corresponding bands are observed in the matrices with large concentrations of xenon. Our experiments show the high efficiency of the formation of large xenon clusters in a neon matrix that can accommodate a major part of phenol molecules. In contrast to the case of xenon, the H-bonded 1:1 phenol⋅⋅⋅N2 complex is found in a neon matrix, and the formation of large N2 clusters embedding phenol molecules is relatively inefficient.
Energy distribution measurement of narrow-band ultrashort x-ray beams via K-edge filters subtraction
Authors: Cardarelli Paolo , Di Domenico Giovanni , Marziani Michele , Muçollari Irena , Pupillo Gaia , Sisini Francesco , Taibi Angelo , Gambaccini Mauro
Published: October 2012

The characterization of novel x-ray sources includes the measurement of the photon flux and the energy distribution of the produced beam. The aim of BEATS2 experiment at the SPARC-LAB facility of the INFN National Laboratories of Frascati (Rome, Italy) is to investigate possible medical applications of an x-ray source based on Thomson relativistic back-scattering. This source is expected to produce a pulsed quasi-monochromatic x-ray beam with an instantaneous flux of 1020 ph/s in pulses 10 ps long and with an average energy of about 20 keV. A direct measurement of energy distribution of this beam is very difficult with traditional detectors because of the extremely high photon flux. In this paper, we present a method for the evaluation of the energy distribution of quasi-monochromatic x-ray beams based on beam filtration with K-edge absorbing foils in the energy range of interest (16–22 keV). The technique was tested measuring the energy distribution of an x-ray beam having a spectrum similar to the expected one (SPARC-LAB Thomson source) by using a tungsten anode x-ray tube properly filtered and powered. The energy distribution obtained has been compared with the one measured with a HPGe detector showing very good agreement.
Harmonic mode competition in a terahertz gyrotron backward-wave oscillator
Authors: Kao S. H. , Chiu C. C. , Chang P. C. , Wu K. L. , Chu K. R.
Published: October 2012

Electron cyclotron maser interactions at terahertz (THz) frequencies require a high-order-mode structure to reduce the wall loss to a tolerable level. To generate THz radiation, it is also essential to employ cyclotron harmonic resonances to reduce the required magnetic field strength to a value within the capability of the superconducting magnets. However, much weaker harmonic interactions in a high-order-mode structure lead to serious mode competition problems. The current paper addresses harmonic mode competition in the gyrotron backward wave oscillator (gyro-BWO). We begin with a comparative study of the mode formation and oscillation thresholds in the gyro-BWO and gyromonotron. Differences in linear features result in far fewer “windows” for harmonic operation of the gyro-BWO. Nonlinear consequences of these differences are examined in particle simulations of the multimode competition processes in the gyro-BWO, which shed light on the competition criteria between modes of different as well as the same cyclotron harmonic numbers. The viability of a harmonic gyro-BWO is assessed on the basis of the results obtained.
Analysis of the external and internal quantum efficiency of multi-emitter, white organic light emitting diodes
Authors: Furno Mauro , Rosenow Thomas C. , Gather Malte C. , Lüssem Björn , Leo Karl
Published: October 2012

We report on a theoretical framework for the efficiency analysis of complex, multi-emitter organic light emitting diodes (OLEDs). The calculation approach makes use of electromagnetic modeling to quantify the overall OLED photon outcoupling efficiency and a phenomenological description for electrical and excitonic processes. From the comparison of optical modeling results and measurements of the total external quantum efficiency, we obtain reliable estimates of internal quantum yield. As application of the model, we analyze high-efficiency stacked white OLEDs and comment on the various efficiency loss channels present in the devices.