bluuebunny/crossref_metadata_2025_split huggingface dataset:
Non‐allosteric enzyme switches possess larger effector‐induced changes in thermodynamic stability than their non‐switch analogs
Authors: Choi Jay H. , San Angela , Ostermeier Marc 
Published: February 2013

AbstractThe ability to regulate cellular protein activity offers a broad range of biotechnological and biomedical applications. Such protein regulation can be achieved by modulating the specific protein activity or through processes that regulate the amount of protein in the cell. We have previously demonstrated that the nonhomologous recombination of the genes encoding maltose binding protein (MBP) and TEM1 β‐lactamase (BLA) can result in genes that confer maltose‐dependent resistance to β‐lactam antibiotics even though the encoded proteins are not allosteric enzymes. We showed that these phenotypic switches—named based on their conferral of a switching phenotype to cells—resulted from a specific interaction with maltose in the cell that increased the switches cellular accumulation. Since phenotypic switches represent an important class of engineered proteins for basic science and biotechnological applications in vivo, we sought to elucidate the phenomena behind the increased accumulation and switching properties. Here, we demonstrate the key role for the linker region between the two proteins. Experimental evidence supports the hypothesis that in the absence of their effector, some phenotypic switches possess an increased rate of unfolding, decreased conformational stability, and increased protease susceptibility. These factors alone or in combination serve to decrease cellular accumulation. The effector functions to increase cellular accumulation by alleviating one or more of these defects. This perspective on the mechanism for phenotypic switching will aid the development of design rules for switch construction for applications and inform the study of the regulatory mechanisms of natural cellular proteins.
Gas chromatography combined with mass spectrometry, flame ionization detection and elemental analyzer/isotope ratio mass spectrometry for characterizing and detecting the authenticity of commercial essential oils of Rosa damascena Mill.
Authors: Pellati Federica , Orlandini Giulia , van Leeuwen Katryna A. , Anesin Giulia , Bertelli Davide , Paolini Mauro , Benvenuti Stefania , Camin Federica 
Published: February 2013

RATIONALEThe essential oil of Rosa damascena Mill. is known for its fine perfumery application, use in cosmetic preparations and for several pharmacological activities. Due to its high value, it can be easily adulterated with flavors or cheaper oils. This study is aimed at a detailed phytochemical characterization of commercial samples of R. damascena essential oil and at their authenticity assessment.METHODSNineteen commercial samples of R. damascena essential oil of different geographic origin and an additional authentic one, directly extracted by hydro‐distillation from fresh flowers, were considered. GC/MS and GC/FID techniques were applied for the phytochemical analysis of the samples. EA/IRMS (Elemental Analyzer/Isotope Ratio Mass Spectrometry) and GC/C (Combustion)/IRMS were used to determine the δ13C composition of bulk samples and of some specific components.RESULTSCitronellol (28.7–55.3%), geraniol (13.5–27.3%) and nonadecane (2.6–18.9%) were the main constituents of Bulgarian and Turkish essential oils, while those from Iran were characterized by a high level of aliphatic hydrocarbons (nonadecane: 3.7–23.2%). The δ13C values of bulk samples were between −28.1 and −26.9‰, typical for C3 plants. The δ13C values of specific components were in the usual range for natural aromatic substances from C3 plants, except for geranyl acetate, which displayed higher values (up to −18‰). These unusual δ13C values were explained by the addition of a natural cheaper oil from a C4 plant (Cymbopogon martinii, palmarosa), which was found to occur in most of the essential oils.CONCLUSIONGC/C/IRMS, in combination with GC/MS and GC/FID, can be considered as an effective and reliable tool for the authenticity control of R. damascena essential oil. Copyright © 2013 John Wiley & Sons, Ltd.
Preservice Elementary Teachers and Explanation Construction: Knowledge‐for‐Practice and Knowledge‐in‐Practice
Authors: ZANGORI LAURA , FORBES CORY T. 
Published: February 2013

ABSTRACTEffectively designed science learning environments revolve around students’ sensemaking through the use of evidence to ground explanations about natural phenomena. However, little research has been conducted to investigate elementary teachers’ learning to promote students’ sensemaking in elementary (K‐5) classrooms. The purpose of this multiple‐case study is to explore how preservice elementary teachers conceptualize and foster students’ construction of evidence‐based explanations. Our findings show that when the preservice teachers had difficulty conceptualizing their ideas about explanation construction, they were also challenged to support students’ explanations constructed in the classroom. They frequently accepted evidence as a complete explanation and afforded their students opportunities to describe evidence rather than formulate evidence‐based claims. Furthermore, each of the preservice teachers articulated rich and varied conceptions of ways to elicit students’ prior knowledge and scaffold new knowledge construction that were not evident in their enactments in the classroom. These findings, which complement and extend those of other studies focused on in‐service elementary teachers, suggest that a lack of emphasis on sensemaking components of scientific practice could be an endemic issue across the teacher professional continuum for which elementary teachers require ongoing and multifaceted forms of support. © 2013 Wiley Periodicals, Inc. Sci Ed 97:310–330, 2013
Alamut: a high‐performance network intrusion detection system in support of virtualized environments
Authors: Sharifi Mohsen , Salimi Hadi , Asadi Ebrahim 
Published: February 2013

ABSTRACTOne of the benefits of virtualization technology is the provision of secure and isolated computing environments on a single physical machine. However, the use of virtual machines for this purpose often degrades the overall system performance that is due to emulation costs, for example, packet filtering on every virtual machine. To allow virtual machines to be favorably used as before for the provision of secure environments but with comparably less performance degradation, we propose a new architecture called Alamut in this paper for restructuring any typical network intrusion detection system (NIDS) to run in a Xen‐based virtual execution environment. In the proposed architecture, primitive mechanisms for implementing the security concerns of typical NIDSs such as signature matching are placed at the kernel level of driver domain (dom0), whereas security policies and management modules are kept in user space of that domain. Separation of mechanisms from policies allows network packets to be verified at the kernel level first hand more efficiently without requiring costly context switches to push them to user space for validation. In addition, system administrators can easily define new policies at user level and determine on which virtual machines these policies should be enforced. A proof‐of‐concept implementation of Alamut has been prototyped on the Xen hypervisor using Bro open‐source NIDS. Experimental results show approximately 3.5‐fold increase in the overall system performance when our prototype is run compared with when Bro is run. Results also show 19% improvement in network throughput. The comparison of Alamut with Snort with the same set of signatures and attacks shows that our prototyped NIDS has lower processor utilization and has captured more packets in heavy network loads. Copyright © 2013 John Wiley & Sons, Ltd.
Content integrity and non‐repudiation preserving audio‐hiding scheme based on robust digital signature
Authors: Zhu Liehuang , Liu Dan , Yu Litao , Xie Yuzhou , Wang Mingzhong 
Published: February 2013

ABSTRACTCurrent secure communication schemes do not take together traffic security and data security (content integrity and non‐repudiation) of the secret message into consideration, making the content prone to blind tampering and compromised party cheating attacks. In this paper, we present a scheme that hides secret audio in cover audio on the basis of robust digital signature to preserve not only hidden communication but also content integrity and non‐repudiation of the secret audio. Furthermore, instead of traditional binary authentication that only outputs yes or no, the authentication of our scheme is flexibly measurable, and the measurement value is in correspondence with the sense of human hearing precisely. Experimental results show that the proposed scheme provides highly robust authentication against content‐preserving degradations with 99.03% of test audios having the strongest authenticity (1.00) and high level of distinct authentication between content‐destructive degradations with 95.01% of test audios having relatively weak authenticity (less than 0.15). As the authentication is flexibly measureable, there is no false alarm in the semantic aspect. Copyright © 2013 John Wiley & Sons, Ltd.
Preorogenic exhumation of the North Pyrenean Agly massif (Eastern Pyrenees‐France)
Authors: Vauchez Alain , Clerc Camille , Bestani Lucie , Lagabrielle Yves , Chauvet Alain , Lahfid Abdeltif , Mainprice David 
Published: February 2013

AbstractThe Pyrenees, north of the North Pyrenean fault, display a complex structure involving a succession of peridotite massifs, basement massifs, and mid‐Cretaceous to Late Cretaceous basins located in a narrow domain, which was affected by a mid‐Cretaceous, preorogenic, high‐temperature, low‐pressure metamorphism. The Late Cretaceous basins were interpreted either as pull‐apart basins formed during transcurrent motion of Iberia relative to Eurasia or as remnants of a larger extensional basin. Recent models support that peridotite massifs result from the exhumation of the mantle during this preorogenic event. The northern boundary of the Agly basement massif shows evidence of ductile deformation of the basal formations of the Agly sedimentary cover. Macroscopic and microscopic kinematics indicators consistent with asymmetry of crystallographic fabrics suggest normal sense of shear and thus suggest detachment, at least partial, of the Mesozoic cover from its basement. Triassic to Early Cretaceous limestones are mylonitic and consistently shows a foliation, a NS‐ to NE‐trending lineation, shear criteria suggesting top‐to‐the‐north shearing and locally boudinage. At the microscopic scale, mylonites are characterized by a very fine grain size, frequently <10 µm. They contain larger, partially recrystallized calcite parent grains and undeformed quartz grains with calcite fringes crystallized in pressure shadows. In these mylonites, calcite systematically shows a weak but well‐defined crystallographic‐preferred orientations, suggesting HT dislocation creep combined to diffusion creep and possibly grain boundary sliding in the finest fraction of the mylonites. Paleotemperatures determined using Raman spectrometry suggest synkinematic temperature conditions in the range 340–390°C, in good agreement with observed microstructures and calcite CPO. The mylonitic fabric in Mesozoic limestones is folded by EW‐trending Pyrenean folds north of the Agly basement massif, attesting that this fabric formed before the Pyrenean orogeny. These data consistently support preorogenic extension under medium‐temperature conditions of the northern Agly massif and likely of the massif itself. Since simultaneously (~100 Ma) a mid‐Cretaceous basin opened south of the basement massif, we suggest a model of preorogenic exhumation of the Agly massif in response to the regional extension associated to the rotation of Iberia. This model may explain the exhumation of the North Pyrenean massifs during a single preorogenic event that allowed the opening of extensional basins and the exhumation of the lithospheric mantle. All these structures being subsequently reworked during the Pyrenean orogeny.
Reduction of radar interference—stealth wind blade structure with carbon nanocomposite sheets
Authors: Kim Jinbong , Lim Dowan 
Published: February 2013

ABSTRACTWind turbines appear to be an ongoing threat to radar systems because of their large radar cross‐sections (RCS). In particular, the Doppler shift of the radar signal caused by blade rotation can confuse even modern Doppler radar systems. To reduce the radar interference problem, this study presents a stealth wind blade structure with a minimal weight increase compared with the conventional wind blade structure, while maintaining the same manufacturing process. The Salisbury screen‐type absorbing structure with a carbon nanocomposite sheet was adapted for the wind blade. The radar‐absorbing structure was integrated with the wind blade structure by sharing the spacer and ground of the absorbing structure with the wind blade structure. A ply of carbon fabric was used as the ground, for which the reflection was verified to be greater than − 0.078 dB over the whole range of X‐band frequencies. The radar‐absorbing structure was designed to have a reflection loss greater than − 40 dB at 10 GHz. The stealth wind blade structure was manufactured via the resin transfer process used for conventional wind blades. The RCS reduction performance of the stealth wind blade was measured in the compact range at 10 GHz, and an RCS reduction of nearly 20 dB was achieved in the angle range of the most severe RCS.Copyright © 2013 John Wiley & Sons, Ltd.
A Review on Nitrosyl Metal Halides and Mass Spectroscopic Support for the Dimeric Structure of [Ni(NO)I]2 and ­[Pd(NO)Cl]2. A Tribute to Walter Hieber (1895–1976) and Fritz Seel (1915–1987)
Authors: Beck Wolfgang , Fischer Gerd , Göbel Michael , Evers Jürgen , Klapötke Thomas M. 
Published: February 2013

AbstractNeutral halogenido nitrosyl metal complexes and their history are reviewed. The mass spectra indicate the dimeric nature of [(ON)Ni(μ‐I)2Ni(NO)] and of [(ON)Pd(μ‐Cl)Pd(NO)] whereas hitherto a tetramer was favored for nitrosyl nickel iodide.
Synthesis and Structural Characterization of Two New Non‐Centrosymmetric Tetrasulfidometalates
Authors: Srinivasan Bikshandarkoil R. , Dhuri Sunder N. , Naik Ashish R. , Näther Christian , Bensch Wolfgang 
Published: February 2013

AbstractThe synthesis and structural characterization of two new group VI tetrasulfidometalates (NH4)6[MS4]3·(hmt)4 [hmt = hexamethylenetetramine; M = W (1); M = Mo (2)] is reported. 1 and 2 are isostructural and crystallize in the non‐centrosymmetric trigonal space group R3c. The (NH4)+ cations, [MS4]2– anions, and hmt molecules are joined by hydrogen bonding to form a three‐dimensional network. In the crystal structure six NH4+ ions and six [MS4]2– anions are arranged to form channels running along [001] hosting a part of the hmt molecules. The channels are surrounded by the remaining hmt molecules. The presence of hmt in the structures of 1 or 2 results in a reduction of the decomposition temperature compared to that of (NH4)2[MS4] and formation of carbon contaminated metal sulfide residues.
MRI morphometric characterisation of the paediatric cervical spine and spinal cord in children with MPS IVA (Morquio‐Brailsford syndrome)
Authors: Solanki Guirish A. , Lo William B. , Hendriksz Christian J. 
Published: February 2013

AbstractNearly all children with MPS IVA develop skeletal deformities affecting the spine. At the atlanto‐axial spine, odontoid hypoplasia occurs. GAG deposition around the dens, leads to peri‐odontoid infiltration. Transverse/alar ligament incompetence causes instability. Atlanto‐axial instability is associated with cord compression and myelopathy, leading to major morbidity and mortality. Intervention is often required. Does the presence of widened bullet shaped vertebra in platyspondily encroach on the spinal canal and cause spinal stenosis in MPS IVA? So far, there have been no standardised morphometric measurements of the paediatric MPS IVA cervical spine to evaluate whether there is pre‐existing spinal stenosis predisposing to compressive myelopathy or whether this is purely an acquired process secondary to instability and compression. This study provides the first radiological quantitative analysis of the cervical spine and spinal cord in a series of affected children. MRI morphometry indicates that the MPS IVA spine is narrower at C1–2 level giving an inverted funnel shape. There is no evidence of a reduction in the Torg ratio (canal‐body ratio) in the cervical spine. The spinal canal does not exceed 11 mm at any level, significantly smaller than normal historical cohorts (14 mm). The sagittal diameter and axial surface area of both spinal canal and cord are reduced. C1–2 level cord compression was evident in the canal‐cord ratio but the Torg ratio was not predictive of cord compression. In MPS IVA the reduction in the space available for the cord (SAC) is multifactorial rather than due to congenital spinal stenosis.
Development of an attachment‐informed measure of sexual behavior in late adolescence
Authors: Szielasko Alicia L. , Symons Douglas K. , Lisa Price E. 
Published: February 2013

ABSTRACTThere is considerable interest in relations between sexual behavior and romantic attachment styles in adolescence as attachment needs are increasingly met through intimate partners rather than parents. The objectives of this research were to organize a measure of sexual behavior within an attachment theory framework, and then show that this new measure uniquely predicted sexual approach styles and invasive sexual experiences. 190 18‐ and 19‐year‐old university students in late adolescence completed sexual behavior items that were provided ambivalent (anxious) and avoidant dimensions. These were systematically related to the romantic attachment dimensions of the Experiences in Close Relationships – Revised. However, even after romantic relationship style, gender, and social desirability were controlled, avoidance in sexual relationships predicted lifetime sexual partner number and negatively predicted positive sexual strategies, and ambivalence in sexual relationships predicted invasive and coercive sexual behaviors. A measure specific to sexual relationships informs the attachment and romantic context of sex in late adolescence.
Cosmogenic nuclide constraints on late Quaternary glacial chronology on the Dalijia Shan, northeastern Tibetan Plateau
Authors: Wang Jie , Kassab Christine , Harbor Jonathan M. , Caffee Marc W. , Cui Hang , Zhang Guoliang 
Published: February 2013

AbstractCosmogenic nuclide (CN) apparent exposure dating has become a widely used method for determining the age of glacial landforms on the Tibetan Plateau with > 1200 published ages. We present the first 10Be exposure ages from the Dalijia Shan, the most northeastern formerly glaciated mountain range on the Tibetan Plateau. The moraine groups identified from field and remote sensing imagery mapping record four glacial events at 37.07 ± 3.70 to 52.96 ± 4.70 ka (MIS 3), 20.17 ± 1.79 to 26.99 ± 2.47 ka (MIS 2), 16.92 ± 1.49 to 18.76 ± 1.88 ka (MIS 2), and 11.56 ± 1.03 to 11.89 ± 1.06 ka (Younger Dryas). These ages indicate that glaciation in the northeastern Tibetan Plateau is much younger than previously thought. In addition, this record is consistent with many other regions on the Tibetan Plateau, with a local last glacial maximum during MIS 3 asynchronous with Northern Hemisphere last glacial maximum during MIS 2. The Dalijia Shan might also include an event of Younger Dryas age, but this needs to be tested in future studies.
A 10-year single-centre experience in percutaneous interventions for multi-stage treatment of hypoplastic left heart syndrome
Authors: Moszura Tomasz , Dryzek Pawel , Goreczny Sebastian , Mazurek-Kula Anna , Moll Jacek J. , Sysa Andrzej , Bobkowski Waldemar , Moll Jadwiga A. , Qureshi Shakeel A. 
Published: February 2013

AbstractObjectivesThe purpose of this paper is to report our 10 years of experience of interventional treatment of patients with hypoplastic left heart syndrome and to focus on the frequency, type, and results of percutaneous interventions during all the stages of palliation, considering the different techniques, devices, and complications.BackgroundConstant progress in surgical treatment of congenital heart defects in the last decade has significantly improved the prognosis for children with hypoplastic left heart syndrome. However, morbidity and mortality remain relatively high. Modern interventional procedures complement or occasionally replace surgical treatment.MethodsBetween January, 2001 and December, 2010, 161 percutaneous interventions were performed in 88 patients with hypoplastic left heart syndrome. Patients were divided into four groups: (a) before the first surgical treatment including hybrid approach, (b) after first-stage Norwood operation, (c) after second-stage bidirectional Glenn operation, and (d) after third-stage Fontan operation.ResultsPercutaneous interventions resulted in statistically significant changes in pulmonary artery pressures, vessel diameters, and O2saturation. Complications occurred in 4.3% of interventions and were related mainly to stent implantation in stenosed pulmonary arteries.ConclusionsPercutaneous interventions may result in haemodynamic stability and reduction in the number of operations. They may result in significant changes in pulmonary artery pressures, vessel diameters, O2saturation, with a low rate of complications, which are mainly related to stent implantation in the pulmonary arteries.
Associations between knowledge of disease, depression and anxiety, social support, sense of coherence and optimism with health-related quality of life in an ambulatory sample of adolescents with heart disease
Authors: Wang QiFeng , Hay Margaret , Clarke David , Menahem Samuel 
Published: February 2013

AbstractIntroductionAdvances in overall management have led to an increasing number of adolescents with congenital heart disease reaching adulthood. This study aimed to evaluate the health-related quality of life in adolescents with heart disease, and examine its relationship with the adolescents’ knowledge and understanding of their congenital heart disease, its severity, and its relationship to the degree of anxiety and depression, feeling of optimism and sense of coherence experienced by the adolescents together with their social support.Methods and resultsAdolescents with heart disease were recruited from an ambulatory setting at a tertiary centre. Patients completed self-report questionnaires including the Paediatric Quality of Life Inventory 3.0-Cardiac Module, a questionnaire assessing the adolescents’ knowledge of their cardiac condition, the Hospital Anxiety and Depression Scale, Multidimensional Scale of Perceived Social Support, Life Orientation Test-Revised, and Sense of Coherence-13, supplemented by clinical information provided by the attending cardiologists. A total of 114 patients aged 12–20 years were recruited over 15 months. In all, 98% of patients were in New York Heart Association class I. Their health-related quality of life was found to positively correlate with a low level of anxiety and depression (Pearson correlation, r = −0.57, p < 0.001), a good knowledge of their cardiac condition (r = 0.31, p < 0.01), feelings of optimism (r = 0.39, p < 0.001), adequate social support (r = 0.27, p < 0.01), and a strong sense of coherence (r = 0.24, p < 0.01).ConclusionsAdolescents’ knowledge and understanding of their cardiac abnormality together with an improved sense of well-being had a positive influence on their health-related quality of life.