bluuebunny/crossref_metadata_2025 huggingface dataset:
Ordinal operations on graph representations of sets
Authors: Kirby Laurence
Published: December 2012

Any set x is uniquely specified by the graph of the membership relation on the set obtained by adjoining x to the transitive closure of x. Thus any operation on sets can be looked at as an operation on these graphs. We look at the operations of ordinal arithmetic of sets in this light. This turns out to be simplest for a modified ordinal arithmetic based on the Zermelo ordinals, instead of the usual von Neumann ordinals. In this arithmetic, addition of sets corresponds to concatenating graphs, and multiplication corresponds to replacing each edge of a graph by a copy of another graph. Characterizations for the von Neumann case are also given.
Nematic Liquid Crystalline Elastomer Grating and Microwire Fabricated by Micro‐Molding in Capillaries
Authors: Wei Renbo , He Yaning , Wang Xiaogong , Keller Patrick
Published: December 2012

A new approach is developed to fabricate highly oriented mono‐domain LCE nano/microstructures through micro‐molding in capillaries. Gratings and microwires as two typical examples are fabricated and characterized by polarizing optical microscopy, optical microscopy, and scanning electron microscopy. The gratings with precisely controlled sizes and smooth surface are obtained by filling the channels with a nematic monomer mixture followed by the photo‐crosslinking. After peeling off the gratings from the substrate, the free‐standing microwires are obtained. A uniform orientation of the mesogenic units is observed for the molds with channel width less than 20 μm. Reversible thermomechanical effect is demonstrated by using the microwires obtained through this approach.
Identification ofN‐acyl‐fumonisinB1 as new cytotoxic metabolites of fumonisin mycotoxins
Authors: Harrer Henning , Laviad Elad L. , Humpf Hans Ulrich , Futerman Anthony H.
Published: December 2012

Scope

Fumonisins are mycotoxins produced byFusariumspecies. The predominant derivative, fumonisinB1 (FB1), occurs in food and feed and is of health concern due to its hepatotoxic and carcinogenic effects. However, the role ofFB1 metabolites on the mechanism of the toxicity, the inhibition of the ceramide synthesis, is unknown. The aim of this study was to identify new fumonisin metabolites and to evaluate their cytotoxic potential.

Methods and results

MS, molecular biology, and in vitro enzyme assays were used to investigate fumonisin metabolism in mammalian cells overexpressing human ceramide synthase (CerS) genes.N‐acyl‐FB1 derivatives were detected as new metabolites in cultured cells at levels of up to 10 pmol/mg of protein. TheN‐acylation ofFB1 and hydrolyzedFB1 was analyzed in several cell lines, including cells overexpressingCerS. The acyl‐chain length of theN‐acyl fumonisins depends on theCerSisoform acylating them. TheN‐acyl fumonisins are more cytotoxic than the parent fumonisinB1.

Conclusion

The identification ofN‐acyl fumonisins with various acyl chain lengths together with the observed cytotoxicity of these compounds is a new aspect of fumonisin‐related toxicity. Therefore, these new metabolites might play an important role in the mode of action of fumonisins.
Dietary intake of green tea polyphenols regulates insulin sensitivity with an increase in AMP‐activated protein kinase α content and changes in mitochondrial respiratory complexes
Authors: Serrano José C. E. , Gonzalo‐Benito Hugo , Jové Mariona , Fourcade Stéphane , Cassanyé Anna , Boada Jordi , Delgado Marco A. , Espinel Alberto E. , Pamplona Reinald , Portero‐Otín Manuel
Published: December 2012

Scope

The intake of food rich in polyphenols is related to a lower incidence in almost all chronic degenerative diseases. However, relatively little is known about the molecular mechanisms involved in its antioxidant properties. The aim of this study was to determine whether the mechanism of action of polyphenols could be related to a modulation in energy uptake and metabolism, and further induced mitochondrial changes.

Methods and results

For this purpose, male C57BL6 mice were fed during 3 months with a tea‐based beverage rich in polyphenols. Insulin sensitivity, tissue oxidative damage biomarkers, as well as energy‐related signaling pathways were determined to evaluate its mechanism of action. As a result, a tissue‐ and protein‐specific subtle reduction in oxidative damage was observed. Skeletal muscle showed mitochondrial changes in respiratory complexes and an increase in AMP‐activated protein kinase α levels, suggesting reduced energy availability. These changes were also associated with adipose tissue cellular metabolism. This was confirmed by a decline in the potential of energy uptake, evidenced by a diminished intestinal and systemic absorption of carbohydrates together with an inhibition of insulin sensitivity.

Conclusions

Our results suggest that the mechanisms of action of green tea polyphenols may be related to their ability to modulate energy uptake leading to mitochondrial adaptations possibly responsible for the changes in protein oxidative damage.
Antitumor effects of dietary black and brown rice brans in tumor‐bearing mice: Relationship to composition
Authors: Choi Sun Phil , Kim Sung Phil , Nam Seok Hyun , Friedman Mendel
Published: December 2012

Scope

Feeding a diet supplemented with 10% (w/w) black and brown rice brans inhibited growth of transplanted tumors in mice.

Methods and results

Black and brown rice brans from Oryza sativa LK1–3‐6–12‐1 and Chuchung cultivars each contained 21 compounds characterized by GC/MS. Mice fed diets with added rice brans for 2 weeks were intracutaneously inoculated with CT‐26 mouse cancer cells and fed the same diet for two additional weeks. Tumor mass was 35 and 19% lower in the black and brown bran‐fed groups, respectively. Tumor inhibition was associated with increases in cytolytic activity of splenic natural killer (NK) cells; partial restoration of nitric oxide production and phagocytosis in peritoneal macrophages; increases in released tumor necrosis factor‐α, IL‐1β, and IL‐6 from macrophages; increases in infiltration of leukocyte into the tumor; and reduction in angiogenesis inside the tumor. Proangiogenic biomarkers vascular endothelial growth factor, cyclooxygenase‐2 (COX‐2), and 5‐lipoxygenase (5‐LOX) were also reduced in mRNA and protein expression. ELISA of tumor cells confirmed reduced expression of COX‐2 and 5‐LOX. Reduced COX‐2 and 5‐LOX expression downregulated vascular endothelial growth factor and inhibited neoangiogenesis inside the tumors.

Conclusion

Induction of NK activity and macrophages and inhibition of angiogenesis seem to contribute to tumor regression.
CMOS quadrature VCO using a passive coupling device
Authors: Jang Sheng‐Lyang , Hsieh Hsuan‐Yu , Chang Chia‐Wei , Hsue Ching‐Wen
Published: December 2012

This article presents a new fully‐integrated quadrature voltage‐controlled oscillator (QVCO), which consists of two differential VCOs coupled via an inductor‐ring. The proposed CMOS QVCO has been implemented with the TSMC 0.18‐μm CMOS technology and the die area is 0.693 × 0.976 mm2. At the supply voltage of 0.7 V, the total power consumption is 2.58 mW. The free‐running frequency of the QVCO is tunable from 5.15 to 5.55 GHz as the tuning voltage is varied from 0 to 0.7 V. The measured phase noise at 1 MHz frequency offset is −120.88 dBc/Hz at the oscillation frequency of 5.28 GHz and the figure of merit of the proposed QVCO is −191.21 dBc/Hz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:310–313, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27283
An injection‐locked frequency quadrupler in 90 nm CMOS technology
Authors: Chang Chia‐Wei , Jang Sheng‐Lyang
Published: December 2012

On‐chip high‐frequency frequency sources suffer from quality (Q)‐factor degradation of varactors.Injection‐locked frequency multipliers allow the design of oscillators running at a frequency lower than required to take the advantage of higher Q‐factor varactor. This article proposes a fully integrated CMOS LC‐tank injection‐locked frequency quadrupler fabricated in the TSMC 90 nm RF‐CMOS process and describes the circuit design, operation principle, and measurement results of the quadrupler. The injection‐locked frequency quadrupler comprises a first‐harmonic injection‐locked oscillator with dual‐injection ports, two frequency doublers and a transformer balun. At the supply voltage of 0.7 V, the dc power consumption is 9.1 mW. At the incident power of 0 dBm, the injection‐locked frequency quadrupler can provide an output signal with the frequency from 24 to 29.6 GHz, while the frequency of the injection signal varies from 6 to 7.4 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:266–269, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27291
Design of a compact broadband circularly‐polarized slot antenna for wireless applications
Authors: Rezaeieh Sasan Ahdi , Şimşek Serkan , Pourahmadazar Javad
Published: December 2012

This article presents design of a compact broadband circularly‐polarized square slot antenna with a coplanar waveguide feed.A circular polarization bandwidth larger than 64.7% (3172–6211 MHz) obtained with the proposed antenna by embedding two inverted‐L grounded strips and a 45° bended strip around corners, whereas the impedance bandwidth can be greatly improved through the tuning stubs. 3 dB axial ratio bandwidth of the proposed CP antenna is large as 64.7% in a frequency band of 3172–6211 MHz. The CP antenna operates in a frequency range from 2.25 to 6.75 GHz and 8.25 to 10.25 GHz with VSWR < 2 impedance bandwidth. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:413–418, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27303
High‐performance metamaterial patch antenna
Authors: Kumar Anand , Kumar V. Dinesh
Published: December 2012

A highly directional patch antenna with a novel fishnet metamaterial as cover has been presented at 92.4 GHz frequency. Partial substrate removal technique is used to suppress the surface wave losses. Result shows 14.91 dB improvements in gain and directionality has been improved to 3.5° as compare to 78.3° in conventional patch antenna. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:409–413, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27304
Phase noise analysis for a mm‐wave VCO configuration
Authors: George Deepa , Sinha Saurabh
Published: December 2012

The letter highlights the importance of modeling the phase noise of an oscillator using the impulse sensitivity function. A Colpitts oscillator in the common collector configuration is analyzed to obtain an expression for its phase noise. The oscillator design is thus optimized for phase noise with respect to process and design parameters. The fabricated voltage‐controlled oscillator at an oscillating frequency of 52.8 GHz has a measured phase noise of −98.9° dBc/Hz at 1 MHz offset. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:290–295, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27320
Design of compact and high selectivity TRI‐band wideband microstrip BPF
Authors: Deng Hong‐wei , Zhao Yong‐jiu , Zhou Xiao‐jun , Fu Yong , Liu Yan‐yun
Published: December 2012

In this article, a novel tri‐band wideband microstrip bandpass filter (BPF) with compact size and high selectivity is proposed using three sets of resonators, that is, λ/4 resonators, short‐stub loaded resonator, and λ/2 resonators.Each of the resonators can not only separately generate one passband, but also mainly control the passband performance. Due to the extended feed lines, parasitic coupling and intrinsic characteristics of the resonators, multiple transmission zeros can be created to improve the selectivity. A tri‐band wideband microstrip BPF centered at 2.0, 3.6, and 5.5 GHz is designed, and the predicted results are confirmed experimentally. The size is only 0.156 × 0.303 λg in which λg is the guided wavelength at 2.0 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:258–261, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27334
Preparation and characterization of novel polyimide‐silica hybrids
Authors: Akhter Toheed , Saeed Shaukat , Siddiqi Humaira Masood , Ok Park O.
Published: December 2012

Polyimide‐silica (PI‐SiO2) hybrids were prepared from a novel polyimide (PI), derived from pyromellitic dianhydride (PMDA), 1,6‐bis(4‐aminophenoxy)hexane (synthesized) and 4,4′‐oxydianiline. SiO2 networks (5–30 wt%) were generated through sol–gel process using either tetraethylorthosilicate (TEOS) or a mixture of 3‐aminopropyltriethoxysilane‐PMDA‐based coupling oligomers (APA) and TEOS. Thin, free standing hybrid films were obtained from the respective mixtures by casting and curing processes. The hybrid films were characterized using Fourier transform infrared, 29Si nuclear magnetic resonance (NMR), field emission scanning electron microscopy (FE‐SEM), energy dispersive X‐ray spectrometry and atomic force microscopy (AFM) techniques. 29Si NMR results provide information about formation of organically modified silicate structures that were further substantiated by FE‐SEM and AFM micrographs. Contact angle measurements and thermogravimetric thermograms reveal that the addition of APA profoundly influences surface energy, interfacial tension, thermal stability and the residual char yield of modified hybrids in comparison to those obtained by mixing only TEOS. It was found that reduced particle size, efficient dispersion and improved interphase interactions were responsible for the eventual property enhancement. Copyright © 2012 John Wiley & Sons, Ltd.
First normal stress difference in capillary extrusion flow of nanometer calcium carbonate‐filled PLLA biocomposites
Authors: Liang Ji‐Zhao
Published: December 2012

The nanometer calcium carbonate (nano‐CaCO3)‐filled poly‐L‐lactide (PLLA) biocomposites were prepared using a twin‐screw extruder. The first normal stress difference of the composites were measured by means of a capillary rheometer under experimental conditions with temperatures ranging from 170 to 200°C and shear rates varying from 50 to 103 s−1. The first normal stress difference (N1) increased roughly linearly with increasing shear stress (τw). The sensitivity of the N1 to τw increased with an increase of the die length–‐diameter ratio, and the N1 value varied slightly with the filler weight fraction (ϕf) as test temperature was constant. When the shear stress was fixed, the N1 reached a minimum value for ϕf = 1%. The values of the N1 of the composite melts decreased roughly linearly with a rise of temperature when the shear rate was constant. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
Effect of EPDM‐g‐MAH on the morphology and properties of PA6/EPDM/HDPE ternary blends
Authors: Zhou Yan , Wang Wei , Dou Rui , Li Lan‐peng , Yin Bo , Yang Ming‐bo
Published: December 2012

The formation of core‐shell morphology within the dispersed phase was studied for composite droplet polymer‐blend systems comprising a polyamide‐6 matrix, ethylene‐propylene‐diene terpolymer (EPDM) shell and high density polyethylene (HDPE) core. In this article, the effect of EPDM with different molecular weights on the morphology and properties of the blends were studied. To improve the compatibility of the ternary blends, EPDM was modified by grafting with maleic anhydride (EPDM‐g‐MAH). It was found that core‐shell morphology with EPDM‐g‐MAH as shell and HDPE as core and separated dispersion morphology of EPDM‐g‐MAH and HDPE phase were obtained separately in PA6 matrix with different molecular weights of EPDM‐g‐MAH in the blends. DSC measurement indicated that there may be some co‐crystals in the blends due to the formation of core‐shell structure. Mechanical tests showed that PA6/EPDM‐g‐MAH/HDPE ternary blends with the core‐shell morphology exhibited a remarkable rise in the elongation at break. With more perfect core‐shell composite droplets and co‐crystals, the impact strength of the ternary blends could be greatly increased to 51.38 kJ m−2, almost 10 times higher than that of pure PA6 (5.50 kJ m−2). POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers
New degradable polyesters from deoxycholic acid and oligo(ethylene glycol)s
Authors: Stanciu Magdalena C , Nichifor Marieta
Published: December 2012

A new class of polyesters was prepared by polycondensation of a bile acid, deoxycholic acid, and an oligo(ethylene glycol) (OEG) with molar mass ranging from 100 to 1500. The chemical structure and composition of the polyesters were confirmed by 1H‐NMR, Fourier transform infrared spectroscopy and HPLC analysis. Polyester molar masses measured by gel permeation chromatography were between 5000 and 20 000. Thermal stability and glass transition temperature decreased with increasing length of OEG. Hydrolytic degradation was also enhanced by the presence of longer chain OEG. Polyesters obtained from OEG with molar mass ≥ 1000 were water soluble, semicrystalline and thermosensitive. As a function of the OEG length used for their preparation, the new polyesters can be useful for biomedical or industrial applications. © 2012 Society of Chemical Industry
Proteomic approach toward personalized sarcoma treatment: Lessons from prognostic biomarker discovery in gastrointestinal stromal tumor
Authors: Kondo Tadashi , Suehara Yoshiyuki , Kikuta Kazutaka , Kubota Daisuke , Tajima Takashi , Mukaihara Kenta , Ichikawa Hiroshi , Kawai Akira
Published: December 2012

Sarcomas range from curable tumors to those causing death via metastasis and recurrence. Thus, there is an urgent need for biomarker identification in order to assess the degree of malignancy, predict prognosis, and evaluate possible therapies. Various proteomic approaches and different clinical materials have been used to this end, and candidate biomarkers have been reported for the different types of sarcomas. However, the sample size used in these biomarker studies was generally insufficient, and thus far, no biomarker has been proved useful in clinics. Given that sarcomas are rare, biomarker validation in this setting is more challenging than in other malignancies. In gastrointestinal stromal tumor, adjuvant therapy has proven to be effective. However, only 40% patients experience metastasis after curative surgery alone, and the rest of the patients may not need adjuvant therapy. Using a proteomic approach, we identified pfetin (potassium channel tetramerization domain containing 12, KCTD 12) as a novel prognostic biomarker for sarcoma, and immunohistochemically confirmed its clinical usefulness by a multiinstitutional validation study. Here, we describe our experience and discuss the critical points in the discovery of this biomarker.
Nanophosphor GdOBr:Ce via combustion synthesis: luminescence results
Authors: Blair Michael W. , Fasoli Mauro , Tornga Stephanie C. , Vedda Anna , Smith Nickolaus A. , Bennett Bryan L. , Hehlen Markus P. , Muenchausen Ross E.
Published: December 2012

We used combustion synthesis to produce phase pure GdOBr:Ce with varying Ce concentration. Several combinations of NH4Br and fuel concentration were tested before phase pure GdOBr:Ce was produced by using a 50% excess of NH4Br and a 50% lean concentration of fuel. In addition to the expected emissions from Ce and Gd, we also detected emissions from Eu3+ and Tb3+. Further research indicated that these extra rare earth emissions were due to impurities in the Gd2O3 starting material. While not the desired effect, we were able to monitor both Eu and Ce intensities as a function of Ce concentration in GdOBr. The Ce emission is seen to reach a maximum between 0.1 and 0.5 mol%. At higher Ce content, the Ce luminescence is quenched because of the concentration quenching effect and the higher concentration of O‐H and N‐H groups as revealed by IR spectra. Eu emission progressively decreases as Ce content increases from a combination of competition with Ce for charge capture in the RL process and the effect of OH and NH groups. As Ce concentration increases the RL intensity ratio of the bands of the Ce doublet changes even though the energy difference between the two bands (0.24 ± 0.1 eV) is compatible with the spin‐orbit splitting of the ground level of Ce3+ (0.25 eV). Fitting results indicate that this relative change is not due to changes in self‐absorption, and the effect may be due to changes in local symmetry of the Ce ion. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Substrate impact on the growth of InN nanostructures by droplet epitaxy
Authors: Kumar Mahesh , Roul Basanta , Bhat Thirumaleshwara N. , Rajpalke Mohana K. , Krupanidhi S. B.
Published: December 2012

The substrate effect on InN nanostructures grown by droplet epitaxy has been studied. InN nanostructures were fabricated on Si(111), silicon nitride/Si(111), AlN/Si(111) and Ge(100) substrates by droplet epitaxy using an RF plasma nitrogen source. The morphologies of InN nanostructures were investigated by field emission scanning electron microscopy (FESEM). The chemical bonding configurations of InN nanostructures were examined by x‐ray photoelectron spectroscopy (XPS). Photoluminescence spectrum slightly blue shifted compared to the bulk InN, indicating a strong Burstein–Moss effect due to the presence of high electron concentration in the InN dots (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Selectively‐sensitive metal‐semiconductor‐metal photodetectors based on AlGaN/AlN and ZnCdS/GaP heterostructures
Authors: Averin S. , Kuznetzov P. , Zhitov V. , Zakharov L. , Alkeev N. , Gladisheva N.
Published: December 2012

We report on the growth, fabrication and characterization of metal‐semiconductor‐metal (MSM) photodetectors based on AlGaN/AlN/Al2O3 and ZnCdS/ZnS/GaP heterostructures. The structures were grown by MOVPE at the temperatures 1050 ºC and 415 ºC respectively. Interdigital Au/Ni Schottky barrier contacts forming MSM‐diode structures were deposited on the surfaces of AlGaN and ZnCdS. The finger width and gap were 3 µm and active diode area 100x100 µm2 thus suggesting short transittimes of photogenerated carriers, low capacitance of the diode structure and high‐speed operation of the detectors. The spectral response of AlGaN MSM‐diodes demonstrates the ability of detectors for true solar‐blind response with maximum current responsivity ∼0.1 A/W at 230 nm under illumination from substrate. The I‐V curves displayed dark currents of ∼50 pA at 40 V bias. The dark current of the ZnCdS diode is much lower (∼2 pA at 40 V), which confirms the high crystalline quality of the ZnCdS‐layer (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature dependence of a‐plane GaN low angle incidence microchannel epitaxy by ammonia‐based metal‐organic molecular beam epitaxy
Authors: Naritsuka Shigeya , Lin Chia‐Hung , Uchiyama Shota , Maruyama Takahiro
Published: December 2012

The growth temperature dependence of a‐plane GaN produced by low angle incidence microchannel epitaxy using NH3‐based metal‐organic molecular beam epitaxy was studied. It was found that the width of the laterally grown region increased with temperature. This was because at low temperatures, {10‐12} side facets were formed, which suppressed the lateral growth process by giving rise to inter‐surface diffusion of Ga adatoms from the side to the top of the growing layer. These facets also caused the lateral growth front to assume a zigzag shape. The formation mechanism of the facets can be understood in terms of the Mullin‐Sekerka instability, by which minute periodic undulations gradually increase with growth time when their period is larger than a certain critical value, which increases with growth temperature. Defects in the epitaxial layers were also studied using transmission electron microscopy. Although the defect density was found to be very low in the laterally grown layer itself, a very large number of dislocations and stacking faults were observed both in the template layer and in the epitaxial regions above the openings. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extended defect system as a main source of non‐radiative recombination in InGaN/GaN LEDs
Authors: Shabunina Evgeniia , Averkiev Nikita , Chernyakov Anton , Levinshtein Michael , Petrov Pavel , Shmidt Natalia
Published: December 2012

The results of low‐frequency noise study of three sets of LEDs classified for their low voltage leakage current (LC) values are reported. The LC values at 1‐2.5 V integrally characterize electrical properties of extended defect system (EDS) that is typical for InGaN/GaN structures. The lower LC value, the smaller concentration of extended defects is. It has been shown that low‐frequency noise peculiarities such as the shape of current dependences of the noise spectral density (SI) and increase in SI with an LC values growth are caused by EDS presence. The point defects (PD) contribution to non‐radiative recombination processes is observed in current density region 10‐2 – 10 A/cm2 where radiative recombination prevails. The non‐radiative caused by EDS at j < 10‐2 A/cm2 and at j > 10 A/cm2. The complicated behavior of EDS with an injection current change has been observed (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Convective boundary layer wind dynamics and inertial oscillations: the influence of surface stress
Authors: Schröter Joel S. , Moene Arnold F. , Holtslag Albert A. M.
Published: December 2012

Investigating the influence of surface friction on the inertial oscillation (IO) of an extratropical, non‐growing, convective boundary layer (CBL), we paid particular attention to the stability‐dependent interactive coupling of shear‐induced turbulence and turbulent friction, which leads to a nonlinear relationship between friction and velocity. We showed that in contrast to common perception, IO damping is controlled not only by friction but also by the dependence of friction on velocity. Furthermore, we found that surface friction not only causes damping but also modifies the restoring force. Using these basic principles, we studied the oscillatory properties (equilibrium, periodicity and damping) of the CBL by means of a model based on Monin–Obukhov surface‐layer similarity (MOS) and the mixed‐layer approximation. We found that the model complies with a quadratic surface stress–velocity relationship (QS) in the neutral limit, and a linear surface stress–velocity relationship (LS) in the proximity of the free‐convective limit. Dynamically, the LS leads to a harmonic oscillation with a constant periodicity and exponential damping of the IO. However, the QS displays rather complex anharmonic behaviour; in comparison with the LS it produces a 50% stronger overall damping and a 100% larger contribution to the restoring force. Considering CBLs of arbitrary stability, we found that the MOS stress–velocity relation can be very well approximated by a much simpler linear combination of the LS and the QS which, respectively, represent the convective and the shear‐induced contributions to friction. This enabled us to link the set of the external parameters (surface roughness, surface buoyancy flux and boundary layer depth) to a set of three effective parameters: the equilibrium velocity, the convective friction constant and the neutral friction constant. Together with the Coriolis coefficient, these parameters completely determine the IO.
Neurophonetics
Authors: Hertrich Ingo , Ackermann Hermann
Published: December 2012

Neurophonetics aims at the elucidation of the brain mechanisms underlying speech communication in our species. Clinical observations in patients with speech impairments following cerebral disorders provided the initial vantage point of this research area and indicated distinct functional‐neuroanatomic systems to support human speaking and listening. Subsequent approaches—considering speech production a motor skill—investigated vocal tract movements associated with spoken language by means of kinematic and electromyographic techniques—allowing, among other things, for the evaluation of computational models suggesting elementary phonological gestures or a mental syllabary as basic units of speech motor control. As concerns speech perception, the working characteristics of auditory processing were first investigated based upon psychoacoustic techniques such as dichotic listening and categorical perception designs. More recently, functional hemodynamic neuroimaging and electrophysiological methods opened the door to the delineation of multiple stages of central auditory processing related to signal detection, classification, sensory memory processes, and, finally, lexical access. Beyond the control mechanisms in a stricter sense, both speech articulation and auditory processing represent examples of ‘grounded cognition’. For example, both domains cannot be restricted to text‐to‐speech translation processes, but are intimately interwoven with neuropsychological aspects of speech prosody, including the vocal expression of affects and the actual performance of speech acts, transforming propositional messages to ‘real’ utterances. Furthermore, during language acquisition, the periphery of language—i.e., hearing and speaking behavior—plays a dominant role for the construction of a language‐specific mental lexicon as well as language‐specific action plans for the production of a speech message.WIREs Cogn Sci2013, 4:191–200. doi: 10.1002/wcs.1211

This article is categorized under:

Linguistics > Language in Mind and Brain
Early recognition of speech
Authors: Remez Robert E. , Thomas Emily F.
Published: December 2012

Classic research on the perception of speech sought to identify minimal acoustic correlates of each consonant and vowel. In explaining perception, this view designated momentary components of an acoustic spectrum as cues to the recognition of elementary phonemes. This conceptualization of speech perception is untenable given the findings of phonetic sensitivity to modulation independent of the acoustic and auditory form of the carrier. The empirical key is provided by studies of the perceptual organization of speech, a low‐level integrative function that finds and follows the sensory effects of speech amid concurrent events. These projects have shown that the perceptual organization of speech is keyed to modulation; fast; unlearned; nonsymbolic; indifferent to short‐term auditory properties; and organization requires attention. The ineluctably multisensory nature of speech perception also imposes conditions that distinguish language among cognitive systems.WIREs Cogn Sci2013, 4:213–223. doi: 10.1002/wcs.1213

This article is categorized under:

Psychology > Language
The basal ganglia
Authors: Braunlich Kurt , Seger Carol
Published: December 2012

Through its connections with widespread cortical areas and with dopaminergic midbrain areas, the basal ganglia are well situated to integrate patterns of cortical input with the dopaminergic reward signal originating in the midbrain. In this review, we consider the functions of the basal ganglia in relation to its gross and cellular anatomy, and discuss how these mechanisms subserve the thresholding and selection of motor and cognitive processes. We also discuss how the dopaminergic reward signal enables flexible task learning through modulation of striatal plasticity, and how reinforcement learning models have been used to account for various aspects of basal ganglia activity. Specifically, we will discuss the important role of the basal ganglia in instrumental learning, cognitive control, sequence learning, and categorization tasks. Finally, we will discuss the neurobiological and cognitive characteristics of Parkinson's disease, Huntington's disease and addiction to illustrate the relationship between the basal ganglia and cognitive function. WIREs Cogn Sci 2013, 4:135–148. doi: 10.1002/wcs.1217

This article is categorized under:

Neuroscience > Anatomy
Synthesis, Structures, and Properties of New Discrete Hetero‐tetranuclear Metallocycle Complexes Based on Macrocyclic Oxamide Metalloligands
Authors: Shi Xiao‐Ming , Li Xiao‐Zeng , Ding Bei‐Bei , Zhu Li‐Na
Published: December 2012

Two new discrete hetero‐tetranuclear metallocycle complexes based on metalloligands, {[Zn2(NiL1)2(H2O)6]·4H2O}n (1) and {[Ca2(NiL2)2(CH3OH)0.5(H2O)7]·CH3OH·2H2O}n (2) were synthesized under self‐assembly conditions and structurally determined. X‐ray diffraction analyses revealed that the two compounds involve the discrete metallocyclic units, which serve as building blocks to further expand to three‐dimensional supramolecular frameworks through second interactions such as hydrogen bonds and π···π stacking interactions. The central ZnII and CaII ions of the compounds 1 and 2 are bridged by macrocyclic oxamido metalloligands fusing the metallocycle with “head‐to‐tail” arrangement. The metallocycles have Zn···Zn distances of 9.48 Å in 1 and Ca···Ca distances of 9.90 Å in 2. Further, compounds 1 and 2 were investigated by thermogravimetric analysis.
Expanding the reach of youth mentoring: Partnering with youth for personal growth and social change
Authors: Liang Belle , Spencer Renée , West Jennifer , Rappaport Nancy
Published: December 2012

The goals of youth mentoring have broadened from redressing youth problems to promoting positive youth development. Yet, many of the principles associated with contemporary conceptualizations of development found in the positive youth development (PYD) and community psychology (CP) literature have yet to be fully integrated into mentoring research and practice. These approaches place greater emphasis on youth as assets to their communities and the promotion of positive development through the cultivation of these assets, often by fostering collaborative partnerships between youth and adults to effect social change. In this paper, we examine how bringing these systemic, asset‐oriented approaches more fully to bear on the youth mentoring process creates opportunities that may both extend the reach and deepen the impact of youth mentoring through the promotion of community, social, and individual change.
Correlates of long‐term participation in a physical activity‐based positive youth development program for low‐income youth: Sustained involvement and psychosocial outcomes
Authors: Ullrich‐French Sarah , McDonough Meghan H.
Published: December 2012

This study examined correlates of long‐term participation in a positive youth development (PYD) program. Low‐income youth (N = 215) age 8–13 of diverse ethnicity participating in a summer physical activity‐based PYD program completed questionnaires at the beginning and end of the program (year 1) and at the beginning of year 2. Those with lower BMI and higher attendance and leader support perceptions were more likely to return to the program the following year. Self‐worth and leader support perceptions at time 2 were higher for returners compared to non‐returners. Among returners, hope increased from year 1 to year 2 and increases in global self‐worth across the first year were maintained over one year. Social support is linked to continued PYD participation. Returners had increased and/or sustained positive perceptions of self‐worth and hope. Programs are encouraged to foster staff–participant relationships and self‐worth, and minimize barriers associated with weight status.
Laser Safety in the Perioperative Setting
Authors: Davis Kathy
Published: December 2012

Laser Safety in the Perioperative Setting, AORN, Inc, Ciné‐Med, producer, 2011, DVD and CD‐ROM, http://cine‐med.com/index.php?nav=aorn&id=1953
Clinical Issues
Authors: Maxwell‐Downing Denise
Published: December 2012

This Month

Patient safety during the transition from paper to electronic health records

Key words: electronic health record (EHR), documentation, paper documentation, electronic documentation, patient safety.

Documentation needed for transitions from paper to electronic health records

Key words: electronic health record (EHR), paper documentation, documentation.

The meaning of electronic health record interoperability

Key words: standardized nursing language, interoperability, Perioperative Nursing Data Set (PNDS).
Using Dynamic Maneuvers in the Computed Tomography/Magnetic Resonance Assessment of Lesions of the Head and Neck
Authors: Çelebi İrfan , Öz Aysel , Sasani Mehdi , Bayındır Petek , Sözen Esra , Vural Çetin , Başak Muzaffer
Published: December 2012

Despite advances in technology, the radiologic assessment of certain head and neck lesions may still pose difficulties because of the complex anatomy of this region, the small and mobile structures that this region harbors, and the apposition of mucosal surfaces in the neutral position. Certain maneuvers have been described in the literature to overcome these difficulties. We review the use of the Valsalva and the modified Valsalva maneuver, the puffed-cheek technique, phonation, and inspiration, with possible applications in head and neck imaging.
Perception of Radiation Exposure and Risk among Patients, Medical Students, and Referring Physicians at a Tertiary Care Community Hospital
Authors: Ricketts Michelle L. , Baerlocher Mark O. , Asch Murray R. , Myers Andy
Published: December 2012

Background

It is important for physicians to be aware of the radiation doses as well as the risks associated with diagnostic imaging procedures that they are ordering.

Methods

A survey was administered to patients, medical students, and referring physicians from a number of specialties to determine background knowledge regarding radiation exposure and risk associated with commonly ordered medical imaging tests.

Results

A total of 127 patients, 32 referring physicians, and 30 medical students completed the survey. The majority of patients (92%) were not informed of the radiation risks associated with tests that they were scheduled to receive and had false perceptions about the use of radiation and its associated risks. Physicians and medical students had misconceptions about the use of ionizing radiation in a number of radiologic examinations; for example, 25% and 43% of physicians and medical students, respectively, were unaware that interventional procedures used ionizing radiation, and 28% of physicians were unaware that mammography used ionizing radiation. Computed tomographies and barium studies were thought to be associated with the least ionizing radiation among physicians.

Conclusion

There is a need for educating the public, medical students, and referring physicians about radiation exposure and associated risk so that (1) patients receiving multiple medical imaging tests are aware of the radiation that they are receiving and (2) physicians and future physicians will make informed decisions when ordering such tests to limit the amount of radiation that patients receive and to promote informed consent among patients.
Extrapulmonary Tuberculosis: Imaging Features beyond the Chest
Authors: MacLean Kelly A. , Becker Annalisa K. , Chang Silvia D. , Harris Alison C.
Published: December 2012

The purpose of this pictorial review is to illustrate the various imaging findings of extrapulmonary tuberculosis. Manifestations of cardiac, central nervous system, head and neck, musculoskeletal, abdominal, genitourinary, and breast tuberculosis will be discussed. Extrapulmonary tuberculosis presents a difficult diagnostic challenge for the radiologist and requires a high index of suspicion, particularly in high-risk populations.
The Usefulness of Gadolinium-Enhanced Images on a Follow-up Magnetic Resonance Image in Suspected Multiple Sclerosis
Authors: Moore Fraser G.A. , Levental Mark
Published: December 2012

Purpose

Multiple sclerosis diagnostic criteria include the presence of gadolinium-enhancing lesions when determining dissemination in space and time. Gadolinium is expensive, increases scan time and patient discomfort, and can, rarely, cause serious adverse effects. Our objective was to determine the usefulness of including gadolinium-enhanced images as part of a follow-up brain magnetic resonance imaging (MRI) in patients with a clinically isolated syndrome.

Methods

Consecutive patients seen between 2008 and 2010 with a clinically isolated syndrome suggestive of multiple sclerosis were prospectively enrolled, had a non–gadolinium-enhanced brain MRI, and consented to a follow-up gadolinium-enhanced brain MRI. The primary outcome was a comparison of the number of patients diagnosed with multiple sclerosis compared with the number who would have been diagnosed without the gadolinium-enhanced images.

Results

Twenty-one patients enrolled, and 2 withdrew. Follow-up MRIs were performed a median of 241 days after the initial MRI. Eleven patients met the primary outcome and were diagnosed with multiple sclerosis: 6 as a result of a second clinical attack and 5 by using imaging criteria for dissemination in space and time. If the gadolinium-enhanced images had not been obtained, then there would have been no change in the primary outcome.

Conclusions

In Canadian centers with similar MRI waiting times to those in our study, the routine use of gadolinium as part of a follow-up MRI in patients with suspected multiple sclerosis may not be clinically useful. Gadolinium-enhanced images could still be obtained on an as-needed basis for specific clinical indications.
My Journey to DNA Repair
Authors: Lindahl Tomas
Published: December 2012

I completed my medical studies at the Karolinska Institute in Stockholm but have always been devoted to basic research. My longstanding interest is to understand fundamental DNA repair mechanisms in the fields of cancer therapy, inherited human genetic disorders and ancient DNA. I initially measured DNA decay, including rates of base loss and cytosine deamination. I have discovered several important DNA repair proteins and determined their mechanisms of action. The discovery of uracil-DNA glycosylase defined a new category of repair enzymes with each specialized for different types of DNA damage. The base excision repair pathway was first reconstituted with human proteins in my group. Cell-free analysis for mammalian nucleotide excision repair of DNA was also developed in my laboratory. I found multiple distinct DNA ligases in mammalian cells, and led the first genetic and biochemical work on DNA ligases I, III and IV. I discovered the mammalian exonucleases DNase III (TREX1) and IV (FEN1). Interestingly, expression of TREX1 was altered in some human autoimmune diseases. I also showed that the mutagenic DNA adduct O6-methylguanine (O6mG) is repaired without removing the guanine from DNA, identifying a surprising mechanism by which the methyl group is transferred to a residue in the repair protein itself. A further novel process of DNA repair discovered by my research group is the action of AlkB as an iron-dependent enzyme carrying out oxidative demethylation.
Time Use in Mothers of Children with Cerebral Palsy: A Comparison Study
Authors: Rassafiani Mehdi , Kahjoogh Mina Ahmadi , Hosseini Ali , Sahaf Robab
Published: December 2012

Objectives

The main goal of this study was to measure time spent in different activities by mothers who have children with cerebral palsy (CP), in comparison to mothers of healthy children.

Methods

This study features a descriptive, cross-sectional and matched case control design. Sixty-seven mothers aged between 25 and 50 years based on inclusion and exclusion criteria were selected. The prototype of the Farsi translation of the Mothers’ Time Use Questionnaire was used to measure the time allocations for different activities in both groups.

Results

Mothers of children with CP spent more time in childcare activities and had a lower level of “satisfaction” in comparison with mothers who have healthy children (p < .05). There were no significant differences in other subtype activities between both groups, namely, paid work, leisure, household chores, and sleeping/resting (p > .05).

Conclusion

There was an imbalance over time use between childcare activities and other subtype activities in mothers who have children with CP as compared to mothers with healthy children. Mothers with children who have CP require more attention, support, and special assistance from the government to meet their specific roles as mothers.
Advancing obstetric anesthesia practices in Georgia through clinical education and quality improvement methodologies
Authors: Ninidze Nino , Bodin Sarah , Ivester Thomas , Councilman Lisa , Clyne Brittany , Owen Medge
Published: December 2012

Objective

To determine whether an integrated program of clinical education and improvement methods regarding the safe use of regional anesthesia for obstetrics would result in improved and sustained practice change in Georgia.

Methods

Between 2006 and 2009, intervention teams undertook several visits to 5 Georgian hospitals. Rates of regional anesthesia for labor and cesarean delivery prior to and following the intervention were collected from participating and non‐participating hospitals. There were multifaceted educational activities and quality improvement activities at intervention sites, including protocol development, social marketing, and supply chain logistics. Host hospitals evaluated the program via a questionnaire.

Results

The use of general anesthesia for cesarean delivery decreased significantly (P < 0.001) and the use of epidural analgesia for labor increased significantly (P < 0.001); there was no change in non‐participating hospitals. Over the course of the program, medication and supply availability improved. Program evaluations were uniformly positive.

Conclusion

A structured program of education and quality improvement led to an increase in the use of regional anesthesia for vaginal and cesarean deliveries. Achievements were sustained during periods of economic and political turmoil.
Are prophylactic antibiotics necessary for urodynamic study?
Authors: Gürbüz Cenk , Güner Bayram , Atış Gökhan , Canat Lütfi , Caşkurlu Turhan
Published: December 2012

The aim of this study was to assess the efficacy of prophylactic fosfomycin tromethamine (FT) and ciprofloxacin in preventing bacteriuria caused by urodynamic studies (UDS). A total of 426 adult patients presenting for UDS were enrolled the study. A midstream urine sample was taken 72 hours before and 5 days after the procedure. All patients underwent a standard UDS. The 411 patients who had sterile urine before intervention were included in the study. Patients were randomized into three groups. Group1 received no prophylaxis (n = 133), Group 2 (n = 141) received oral ciprofloxacin (500 mg) 1 hour before the procedure, and Group 3 (n = 137) received a single dose of FT approximately 12 hours before the procedure. Bacteriuria was evaluated for each group. Bacteriuria was detected in 3 (2.3%), 6 (4.3%) and 3 patients (1.6%) in Group 1, Group 2, and Group 3, respectively. The most common identified microorganism was Escherichia coli (E coli) in 6 patients (50%). Among the E coli group, extended spectrum beta‐lactamase producing E coli was seen in 2 patients (33.3%). Univariate analysis demonstrated that a history of urogenital operation (p < 0.01) and female gender (p < 0.01) were significant risk factors for bacteriuria. On multiple logistic regression analysis, the past urogenital operation history was the only significant independent risk factor for significant bacteriuria after UDS (OR = 14, 95% CI = 1.82–23.8, p = 0.01). The prevalence of bacteriuria after UDS was relatively low in the current study population. Therefore, for most patients, it may be unnecessary to use preventive prophylactic antibiotics. However, our results suggest that in patients with a previous history of urologic surgery, the risk for significant bacteriuria is increased and the use of prophylaxis should be considered.