bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computing Pre‐University: Secondary Level Computing Curricula
Authors: Ragonis Noa 
Published: March 2009

AbstractThis article reviews the teaching of computing in high schools throughout the world. Many approaches exist to teaching computing topics to high‐school students, which range from the use of basic computer applications, such as word processors and presentation software, and through the use of advanced applications, such as spread sheets, databases and the construction of basic websites, to some highly advanced computing programs that approach academic curricula.Various agencies and countries have invested great efforts over the years in the updating of curricula following rapid developments in the domain. Deliberations are many and they are manifested in the different names given to the curricula, in the diversity of their targets and contents, and in the wide range of guidelines offered vis‐á‐vis teaching approaches. The common denominator of all such curricula emphasizes the need to prepare students for the world of tomorrow, in all that pertains to computerization. Such training must refer to principles rather than be based on mastering of one tool or programming language rather than another. The article first presents the different approaches that emerge with respect to computing curricula, and then it offers a detailed review of curricula from 19 countries worldwide. Finally, a summarizing comparison between the various curricula is presented in conclusion. It to be viewed that even in countries that have curricula in place, there is still lack in terms of the implementing it. Implementation vis‐á‐vis the general population is more extensive in the prevalent areas of information technology (IT) or information and communication technology (ICT), but it is significantly less extensive in the area of computer science. It seems that most countries are still a long way from achieving their education vision with respect to the domain of computing, and plenty of work still must be done.
Magnetic Multi‐Functional Nano Composites for Environmental Applications
Authors: Dong Jie , Xu Zhenghe , Kuznicki Steven M. 
Published: March 2009

AbstractA novel concept is proposed to synthesize a new class of composites featuring magnetic, molecular sieve and metallic nanoparticle properties. These multi‐functional materials have potential applications as recyclable catalysts, disinfectants and sorbents. The magnetic property enables effective separation of the spent composites from complex multiphase systems for regeneration and recycle, safe disposal of the waste and/or recovery of loaded valuable species. The zeolite molecular sieve provides a matrix which supports a remarkably new, simple, efficient and economical method to make stable, supported silver nanoparticles by silver ion exchange and controlled thermal reduction. The silver nanoparticles generated in this way have excellent properties such as high reactivity and good thermal stability without aggregation, which act as nano reactors for desired functionality in a wide range of applications. Magnetic component (Fe3O4), molecular sieve matrix (zeolite) and silver nanoparticles generated by ion exchange followed by controlled reduction, together form this unique novel composite with designed functions. It represents a practically operational, economical, sustainable and environmentally friendly new advanced functional material. This paper focuses on the novel synthesis and characterization of the composite, with an example of applications as sorbents for the removal of vapor‐phase mercury from the flue gas of coal‐fired power plants.
The Implications of Polymer Selection in Regenerative Medicine: A Comparison of Amorphous and Semi‐Crystalline Polymer for Tissue Regeneration
Authors: Kofron Michelle D. , Griswold Allison , Kumbar Sangamesh G. , Martin Kylie , Wen Xuejun , Laurencin Cato T. 
Published: March 2009

AbstractBiodegradable polymeric scaffolds are being investigated as scaffolding materials for use in regenerative medicine. While the in vivo evaluation of various three‐dimensional (3D), porous, biodegradable polymeric scaffolds has been reported, most studies are ≤3 months in duration, which is typically prior to bulk polymer degradation, a critical event that may initiate an inflammatory response and inhibit tissue formation. Here, a 6 month in vitro degradation and corresponding in vivo studies that characterized scaffold changes during complete degradation of an amorphous, 3D poly(lactide‐co‐glycolide)(3D‐PLAGA) scaffold and near‐complete degradation of a semi‐crystalline3D‐PLAGA scaffold are reported. Using sintered microsphere matrix technology, constructs were fabricated in a tubular shape, with the longitudinal axis void and a median pore size that mimicked the architecture of native bone. Long‐term quantitative measurements of molecular weight, mechanical properties, and porosity provided a basis for theorization of the scaffold degradation process. Following implantation in a critical size ulnar defect model, histological analysis and quantitative microCT indicated early solubilization of the semi‐crystalline polymer created an acidic microenvironment that inhibited mineralized tissue formation. Thus, the use of amorphous over semi‐crystalline PLAGA materials is advocated for applications in regenerative medicine.
Polypyrrole Nanotubes Conjugated with Human Olfactory Receptors: High‐Performance Transducers for FET‐Type Bioelectronic Noses
Authors: Yoon Hyeonseok , Lee Sang Hun , Kwon Oh Seok , Song Hyun Seok , Oh Eun Hae , Park Tai Hyun , Jang Jyongsik 
Published: March 2009

AbstractReingeschnuppert: Polypyrrol‐Nanoröhren, die mit dem menschlichen olfaktorischen Rezeptor (hOR) konjugiert waren, wurden in Feldeffekttransistoren integriert, um leistungsfähige bioelektronische Nasen herzustellen (siehe Bild; S=Source, D=Drain). Das Gerät kann hOR‐Geruchsstoff‐Wechselwirkungen in ein messbares Signal übertragen und zeigte hochempfindliche und spezifische Reaktionen auf einen ausgewählten Geruchsstoff.magnified image
Effects of radio frequency magnetic fields on iron release from cage proteins
Authors: Céspedes Oscar , Ueno Shoogo 
Published: March 2009

AbstractFerritin, the iron cage protein, contains a superparamagnetic ferrihydrite nanoparticle formed from the oxidation and absorption of Fe2+ ions. This nanoparticle increases its internal energy when exposed to alternating magnetic fields due to magnetization lag. The energy is then dissipated to the surrounding proteic cage, affecting its functioning. In this article we show that the rates of iron chelation with ferrozine, an optical marker, are reduced by up to a factor of 3 in proteins previously exposed to radio frequency magnetic fields of 1 MHz and 30 µT for several hours. The effect is non‐thermal and depends on the frequency‐amplitude product of the magnetic field. Bioelectromagnetics 30:336–342, 2009. © 2009 Wiley‐Liss, Inc.
Chaperoning stem cells: a role for heat shock proteins in the modulation of stem cell self‐renewal and differentiation?
Authors: Prinsloo Earl , Setati Mokgadi M. , Longshaw Victoria M. , Blatch Gregory L. 
Published: March 2009

AbstractSelf‐renewal and differentiation of stem cells are tightly regulated processes subject to intrinsic and extrinsic signals. Molecular chaperones and co‐chaperones, especially heat shock proteins (Hsp), are ubiquitous molecules involved in the modulation of protein conformational and complexation states. The function of Hsp, which are typically associated with stress response and tolerance, is well characterized in differentiated cells, while their role in stem cells remains unclear. It appears that embryonic stem cells exhibit increased stress tolerance and concomitant high levels of chaperone expression. This review critically evaluates stem cell research from a molecular chaperone perspective. Furthermore, we propose a model of chaperone‐modulated self‐renewal in mouse embryonic stem cells.
Ligand‐induced activation of the insulin receptor: a multi‐step process involving structural changes in both the ligand and the receptor
Authors: Ward Colin W. , Lawrence Michael C. 
Published: March 2009

AbstractCurrent models of insulin binding to the insulin receptor (IR) propose (i) that there are two binding sites on the surface of insulin which engage with two binding sites on the receptor and (ii) that ligand binding involves structural changes in both the ligand and the receptor. Many of the features of insulin binding to its receptor, namely B‐chain helix interactions with the leucine‐rich repeat domain and A‐chain residue interactions with peptide loops from another part of the receptor, are also seen in models of relaxin and insulin‐like peptide 3 binding to their receptors. We show that these principles can likely be extended to the group of mimetic peptides described by Schäffer and coworkers, which are reported to have no sequence identity with insulin. This review summarizes our current understanding of ligand‐induced activation of the IR and highlights the key issues that remain to be addressed.
Structural analysis of the human cannabinoid receptor one carboxyl‐terminus identifies two amphipathic helices
Authors: Ahn Kwang H. , Pellegrini Maria , Tsomaia Natia , Yatawara Achani K. , Kendall Debra A. , Mierke Dale F. 
Published: March 2009

AbstractRecent research has implicated the C‐terminus of G‐protein coupled receptors in key events such as receptor activation and subsequent intracellular sorting, yet obtaining structural information of the entire C‐tail has proven a formidable task. Here, a peptide corresponding to the full‐length C‐tail of the human CB1 receptor (residues 400–472) was expressed inE.coliand purified in a soluble form. Circular dichroism (CD) spectroscopy revealed that the peptide adopts an α‐helical conformation in negatively charged and zwitterionic detergents (48–51% and 36–38%, respectively), whereas it exhibited the CD signature of unordered structure at low concentration in aqueous solution. Interestingly, 27% helicity was displayed at high peptide concentration suggesting that self‐association induces helix formation in the absence of a membrane mimetic. NMR spectroscopy of the doubly labeled (15N‐ and13C‐) C‐terminus in dodecylphosphocholine (DPC) identified two amphipathic α‐helical domains. The first domain, S401‐F412, corresponds to the helix 8 common to G protein‐coupled receptors while the second domain, A440‐M461, is a newly identified structural motif in the distal region of the carboxyl‐terminus of the receptor. Molecular modeling of the C‐tail in DPC indicates that both helices lie parallel to the plane of the membrane with their hydrophobic and hydrophilic faces poised for critical interactions. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 565–573, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Biophysical characterization and unfolding of LEF4 factor of RNA polymerase from AcNPV
Authors: Rasheedi Sheeba , Suragani Madhuri , Haq Soghra K. , Ghosh Sudip , Ehtesham Nasreen Z. , Hasnain Seyed E. 
Published: March 2009

AbstractLate expression factor 4 (LEF4) is one of the four subunits of Autographa californica nuclear polyhedrosis virus (AcNPV) RNA polymerase. LEF4 was overexpressed in Escherichia coli and recombinant protein was subjected to structural characterization. Chemical induced unfolding of LEF4 was investigated using intrinsic fluorescence, hydrophobic dye binding, fluorescence quenching, and circular dichroism (CD) techniques. The unfolding of LEF4 was found to be a non‐two state, biphasic transition. Intermediate states of LEF4 at 2M GnHCl and 4M urea shared some common structural features and hence may lie on the same pathway of protein folding. Steady‐state fluorescence and far‐UV CD showed that while there was considerable shift in the wavelength of emission maximum (λmax), the secondary structure of LEF4 intermediates at 2M GnHCl and 4M urea remained intact. Further, temperature induced denaturation of LEF4 was monitored using far‐UV CD. This study points to the structural stability of LEF4 under the influence of denaturants like urea and temperature. Although LEF4 is an interesting model protein to study protein folding intermediates, in terms of functional significance the robust nature of this protein might reflect one of the several strategies adapted by the virus to survive under very adverse environmental and physiological conditions. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 574–582, 2009.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Hydrophobic interaction chromatography in dual salt system increases protein binding capacity
Authors: Senczuk Anna M. , Klinke Ralph , Arakawa Tsutomu , Vedantham Ganesh , Yigzaw Yinges 
Published: March 2009

AbstractHydrophobic interaction chromatography (HIC) uses weakly hydrophobic resins and requires a salting‐out salt to promote protein–resin interaction. The salting‐out effects increase with protein and salt concentration. Dynamic binding capacity (DBC) is dependent on the binding constant, as well as on the flow characteristics during sample loading. DBC increases with the salt concentration but decreases with increasing flow rate. Dynamic and operational binding capacity have a major raw material cost/processing time impact on commercial scale production of monoclonal antibodies. In order to maximize DBC the highest salt concentration without causing precipitation is used. We report here a novel method to maintain protein solubility while increasing the DBC by using a combination of two salting‐out salts (referred to as dual salt). In a series of experiments, we explored the dynamic capacity of a HIC resin (TosoBioscience Butyl 650M) with combinations of salts. Using a model antibody, we developed a system allowing us to increase the dynamic capacity up to twofold using the dual salt system over traditional, single salt system. We also investigated the application of this novel approach to several other proteins and salt combinations, and noted a similar protein solubility and DBC increase. The observed increase in DBC in the dual salt system was maintained at different linear flow rates and did not impact selectivity. Biotechnol. Bioeng. 2009;103: 930–935. © 2009 Wiley Periodicals, Inc.
Novel method for fabrication of skeletal muscle construct from the C2C12 myoblast cell line using serum‐free medium AIM‐V
Authors: Fujita Hideaki , Shimizu Kazunori , Nagamori Eiji 
Published: March 2009

AbstractWe have fabricated muscle tissue from murine myoblast cell line C2C12 by modifying the previously reported method. Fabrication of skeletal muscle tissue has been performed in many ways including the use of a biodegradable scaffold, a collagen gel‐embedded culture, or cell sheet tissue engineering, but the extent of tension generation remains low. Recently, a new skeletal muscle tissue engineering technique involving self‐dissociation of a cell sheet from a laminin‐coated polydimethylsiloxane surface was reported which mostly involved a primary cell culture or co‐culture of C2C12 and 10T1/2 cells. In this study, we succeeded in fabricating muscle tissue using C2C12 cells alone by enhancing cell–cell attachment by the use of serum‐free medium AIM‐V. C2C12 cells were seeded on to a laminin‐coated PDMS surface in a 35 mm culture dish with two silk sutures of 5 mm in length each pinned at two places 18 mm apart. Then, cells were allowed to differentiate in AIM‐V, and the cells started to dissociate in a sheet‐like manner after 5–8 days of differentiation. The cells remained attached to the silk sutures, and tissue having a cylindrical morphology was fabricated. After the cylindrical morphology had been obtained, the medium was changed to DMEM supplemented with 2% horse serum, followed by culture for an additional 5–8 days for maturation. Tissue fabricated using this method was excitable with electric pulse stimulation and the generated active tension was approximately 1.4× greater than that reported previously for a co‐culture of C2C12 and 10T1/2 cells. Immuno‐fluorescence study revealed the presence of a sarcomere structure within the fabricated tissue, and Western blotting confirmed the expression of muscle specific‐proteins. The increased active tension generation compared to that with the previously reported method is probably attributable to the increased proportion of myogenic cells in the tissue. Myooid fabricated from mono‐culture of C2C12 will be useful in the muscle study, especially in the area where gene modification is needed. Biotechnol. Bioeng. 2009;103: 1034–1041. © 2009 Wiley Periodicals, Inc.
Intergenerational linkages in antisocial behaviour
Authors: Thornberry Terence P. , Freeman‐Gallant Adrienne , Lovegrove Peter J. 
Published: March 2009

AbstractBackground A life‐course perspective was used to examine whether a parent's adolescent antisocial behaviour increases the chances of his or her child being involved in antisocial behaviour and, if so, the extent to which different aspects of parenting mediate this relationship.Aim It was hypothesised that there will be significant levels of intergenerational continuity in antisocial behaviour when parents have ongoing contact with the child, and that stress from parenting and ineffective parenting styles will mediate this relationship.Method Longitudinal data from the Rochester Intergenerational Study were used to test these issues in structural equation models for fathers and for mothers.Results Parental antisocial behaviour is significantly related to child antisocial behaviour for mothers and for fathers who have frequent contact with the child, but not for fathers with infrequent contact. For mothers, the impact of adolescent antisocial behaviour on the child's antisocial behaviour is primarily mediated through parenting stress and effective parenting. For high‐contact fathers there are multiple mediating pathways that help explain the impact of their adolescent antisocial behaviour on their child's behaviour.Conclusions The roots of antisocial behaviour extend back at least to the parent's adolescence, and parenting interventions need to consider these long‐term processes. Copyright © 2009 John Wiley & Sons, Ltd.
Association of criminal convictions between family members: Effects of siblings, fathers and mothers
Authors: van de Rakt Marieke , Nieuwbeerta Paul , Apel Robert 
Published: March 2009

AbstractBackground Crime runs in families. Previous research has shown the existence of intergenerational transmission of criminal behaviour.Aim The aim of the present study was to investigate the extent to which variation in criminal convictions may be explained by the criminality of siblings and by the intergenerational transmission of criminal behaviour.Method Data from the Dutch Criminal Career and Life‐course Study (CCLS) were used to analyse cross‐tabulations and to conduct multi‐level logistic regression analyses.Results The results indicate that criminal convictions of other family members are indeed correlated with individual conviction risk. The criminal history of siblings is most strongly correlated with the convictions of focal respondents. Results furthermore show that parental convictions only account modestly for the association of criminal convictions between siblings.Conclusions These findings indicate that a direct influence between siblings is plausible, providing support for learning or imitation theories. Copyright © 2009 John Wiley & Sons, Ltd.
Family factors in the intergenerational transmission of offending
Authors: Farrington David P. , Coid Jeremy W. , Murray Joseph 
Published: March 2009

AbstractBackground Convicted parents tend to have convicted children, but there have been few previous studies of transmission between three generations, especially including both records and interviews for hundreds of people.Method In the Cambridge Study in Delinquent Development (CSDD), 411 south London males have been followed up from age 8 to age 48. These males (generation 2, G2) are compared with their fathers and mothers (generation 1, G1), and with their biological sons and daughters (generation 3, G3).Results There was significant intergenerational transmission of convictions from G1 males to G2 males, and from G2 males to G3 males. Convictions of fathers still predicted convictions of sons after controlling for risk factors, but the predictive efficiency was reduced. Transmission was less from G1 females to G2 males, and from G2 males to G3 females. There was little evidence of intergenerational transmission from G1 to G3, except from grandmothers to granddaughters.Conclusions The intergenerational transmission of offending may be mediated by family, socio‐economic and individual risk factors. Intervention to reduce intergenerational transmission could target these risk factors. Copyright © 2009 John Wiley & Sons, Ltd.
Carotid stent fracture: Diagnosis and management
Authors: Boehm Gernot , Gschwendtner Manfred , Schillinger Martin 
Published: March 2009

AbstractWith increasing numbers of carotid stent implantations, stent fractures likely will be detected in this vessel region. The authors report two cases of stent fracture: one balloon expandable and one self expandable stent fractured and caused symptoms. CT angiography identified the stent fractures. One partial stent fracture in the internal carotid artery caused a significant restenosis. One complete stent fracture in the common carotid artery caused neurological symptoms, but no significant restenosis. Computerized tomographic angiography (CTA) findings were confirmed by conventional angiography and treated by repeated stent implantation. In a 12‐month follow‐up period, both patients remained further neurologically asymptomatic and there was no restenosis in duplex sonography or CTA. © 2009 Wiley‐Liss, Inc.
Synthesis and Plasmon‐Induced Charge‐Transfer Properties of Monodisperse Gold‐Doped Titania Microspheres
Authors: Wang Ping , Xie Teng‐Feng , Li Hai‐Yan , Peng Liang , Zhang Yu , Wu Tong‐Shun , Pang Shan , Zhao Yun‐Feng , Wang De‐Jun 
Published: March 2009

AbstractFunctional spheres: Monodisperse gold‐doped titania spheres with tunable sizes under high concentration of titanium precursor have been synthesized by introducing trace amounts of chloroauric acid into the reaction system. Surface photovoltage, surface photocurrent, and transient photovoltage measurements (see figure) of annealed samples reveal that gold nanodots can act as both electron acceptors and donors under the illumination of different wavelengths of light.magnified imageMonodisperse gold‐doped titania microspheres have been synthesized under high concentration of a titanium precursor (9.34 mM) by introducing a trace amount of chloroauric acid (CA) into the reaction system; the size of the microspheres can be easily tuned (from ≈587 to ≈392 nm) by varying the amount of the CA added. The plausible formation mechanism has been discussed in detail. Chloroauric acid was found to act as the stabilizing agent to induce the formation of monodisperse colloidal spheres. Gold‐doped anatase titania spheres with ≈7 nm gold nanodots on the surface were synthesized by calcination. Interestingly, results from surface photocurrent, surface photovoltage, and transient photovoltage measurements indicate that the gold nanodots exhibit different electronic properties when the gold‐doped anatase titania spheres were illuminated by different wavelengths of light: one is an electron acceptor in the UV region, while the other is an electron donor in the visible region. Furthermore, the decay time of the injected plasmon‐induced electrons was found to be on the millisecond timescale and increased with increasing amounts of gold doped.