bluuebunny/crossref_metadata_2025 huggingface dataset:
The virtual power principle in fluid mechanics
Authors: Yu Yongliang
Published: March 2014

A conceptual framework on analytical mechanics for continuous fluid medium, which connects the fluid motion and all of the (internal and external) forces with mechanical power, is proposed by using the virtual power and the virtual velocity. Based on this framework, it is found that the internal virtual power is equal to the external virtual power in fluid dynamics, which is called the virtual power principle. This framework is also proved to be equivalent to the vector dynamics (Cauchy’s equation or Navier–Stokes equation). Furthermore, based on the virtual power principle, a theorem is introduced for continuous fluid medium, which indicates the relationship between the force (or torque) acting on a body immersed in a fluid and the specified virtual power. Subsequently, according to Galilean invariance, the detailed relationship for Newtonian fluids in incompressible flows is derived and used to illustrate the mechanisms on instantaneous forces: the added inertial effects, the boundary energy flux and dissipation effects, the vortex contribution, and the explicit body force contribution. As an application of the principle, the advantage of the V formation flight of geese is preliminarily discussed in the view of aerodynamics. Specifically, the total drag of the flock is reduced by contrast with the simple sum of the drag in solo fight and the optimal angle of V ranges from$60^{\circ }$to$120^{\circ }$. The principle could be a useful approach to reveal the contributions of the flow structures and the moving or deforming boundaries to the force and torque acting on a body, especially in a multibody system.
Direct numerical simulation of turbulent scalar transport across a flat surface
Authors: Herlina H. , Wissink J. G.
Published: March 2014

To elucidate the physical mechanisms that play a role in the interfacial transfer of atmospheric gases into water, a series of direct numerical simulations of mass transfer across the air–water interface driven by isotropic turbulence diffusing from below has been carried out for various turbulent Reynolds numbers ($R_T=84,195,507$). To allow a direct (unbiased) comparison of the instantaneous effects of scalar diffusivity, in each of the DNS up to six scalar advection–diffusion equations with different Schmidt numbers were solved simultaneously. As far as the authors are aware this is the first simulation that is capable to accurately resolve the realistic Schmidt number, $\mathit{Sc}=500$, that is typical for the transport of atmospheric gases such as oxygen in water. For the range of turbulent Reynolds numbers and Schmidt numbers considered, the normalized transfer velocity $K_L$ was found to scale with $R_T^{-{1/2}}$ and $\mathit{Sc}^{-{1/2}}$, which indicates that the largest eddies present in the isotropic turbulent flow introduced at the bottom of the computational domain tend to determine the mass transfer. The $K_L$ results were also found to be in good agreement with the surface divergence model of McCready, Vassiliadou & Hanratty (AIChE J., vol. 32, 1986, pp. 1108–1115) when using a constant of proportionality of 0.525. Although close to the surface large eddies are responsible for the bulk of the gas transfer, it was also observed that for higher $R_T$ the influence of smaller eddies becomes more important.
Thermal transpiration flow through a single rectangular channel
Authors: Yamaguchi Hiroki , Rojas-Cárdenas Marcos , Perrier Pierre , Graur Irina , Niimi Tomohide
Published: March 2014

A thermal transpiration flow through a single rectangular micro-channel was studied experimentally for various gas species, including all rare gases, in order to investigate the influence of gas species on the flow properties. The final equilibrium flow characteristics and relaxation time of the pressure variation were evaluated as functions of the rarefaction parameter. The thermal molecular pressure difference was well fitted by the log-normal distribution function, and its magnitude was found to be strongly dependent on the gas species: a larger pressure difference was obtained for molecules of smaller diameter. However, for the thermal molecular pressure ratio and the thermal molecular pressure exponent, which are dimensionless quantities, the dependence on the gas species was negligible. The relaxation time of the pressure variation was well normalized by the characteristic time of the system. The influence of the geometry was evaluated by comparing the present results, obtained for the case of a rectangular channel, with already published data obtained for the case of a circular cross-section tube. The comparison showed that these two geometrical configurations influence the fluid flow in equal manner, if appropriate geometrical parameters are used for their representation.
Zircon geochronology of intrusive rocks from Cap de Creus, Eastern Pyrenees
Authors: DRUGUET ELENA , CASTRO ANTONIO , CHICHORRO MARTIM , PEREIRA M. FRANCISCO , FERNÁNDEZ CARLOS
Published: March 2014

New petrological and U–Pb zircon geochronological information has been obtained from intrusive plutonic rocks and migmatites from the Cap de Creus massif (Eastern Pyrenees) in order to constrain the timing of the thermal and tectonic evolution of this northeasternmost segment of Iberia during late Palaeozoic time. Zircons from a deformed syntectonic quartz diorite from the northern Cap de Creus Tudela migmatitic complex yield a mean age of 298.8±3.8 Ma. A syntectonic granodiorite from the Roses pluton in the southern area of lowest metamorphic grade of the massif has been dated at 290.8±2.9 Ma. All the analysed zircons from two samples of migmatitic rocks yield inherited ages from the Precambrian metasedimentary protolith (with two main age clusters at c. 730–542 Ma and c. 2.9–2.2 Ga). However, field structural relationships indicate that migmatization occurred synchronously with the emplacement of the quartz dioritic magmas at c. 299 Ma. Thus, the results of this study suggest that subduction-related calc-alkaline magmatic activity in the Cap de Creus was coeval and coupled with D2 dextral transpression involving NNW–SSE crustal shortening during Late Carboniferous – Early Permian time (c. 299–291 Ma). Since these age determinations are within the range of those obtained for undeformed (or slightly deformed) calc-alkaline igneous rocks from NE Iberia, it follows that the Cap de Creus massif would represent a zone of intense localization of D2 transpression and subsequent D3 ductile wrenching that extended into the Lower Permian during a transitional stage between the Variscan and Cimmerian cycles.
DEVELOPMENT AND VALIDATION OF A SHORT SCALE TO MEASURE HOW SOCIAL RELATIONSHIPS SUPPORT THE CONTINUOUS AND CONSCIOUS ENDEAVOUR TO LOSE WEIGHT
Authors: TAKADA AKEMI , TAKAHASHI YOSHIMITSU , NISHIMURA SHUZO , KOSUGI SHINJI
Published: March 2014

This paper reports the development of a short scale (ten items) entitled ‘Social Relationships to Prevent Obesity’ (SRPO), which examines how social relationships support the continuous and conscious endeavour to lose weight. The construct and criterion validity of this scale were ascertained in this study. Factor structure and reliability were examined using data from a randomized controlled trial. A confirmatory factor analysis of the SRPO revealed three relevant factors. The results suggest that the SRPO has both validity and clinical utility and can thus be used as a screening tool in weight-loss interventions and to assess the degree of, and trends in, self-control for weight loss in individuals. The scale can also be used to examine the environmental and self-control problems faced by obese people – factors that should be considered when conducting weight-loss interventions.
Microsatellite variation of mussels (Mytilus galloprovincialis) in central and eastern Mediterranean: genetic panmixia in the Aegean and the Ionian Seas
Authors: Giantsis Ioannis A. , Mucci Nadia , Randi Ettore , Abatzopoulos Theodore J. , Apostolidis Apostolos P.
Published: March 2014

Genetic variation of musselsMytilus galloprovincialisin central–eastern Mediterranean Sea is investigated in this study. A total of 550 individuals sampled from two cultured and 11 wild populations from Italy, Croatia, Greece and Turkey were genotyped at 10 microsatellite loci. Significant deviations from Hardy–Weinberg expectations were observed in more than 75% of the tests performed. All populations showed extensive heterozygote deficits, which remained at significant levels even after correction for null alleles, providing evidence that null alleles were only partly responsible for deviations from Hardy–Weinberg equilibrium in these molluscs. Moreover, null alleles seem to have limited influence on the population genetic differentiation. Similar levels of multi-locus heterozygosity and allelic richness were observed in all populations, cultured and wild, implying the sustainability of the exploited populations. Lack of isolation by distance and markedly low genetic differentiation between the nine Greek sampling sites (shoreline >1000 km) was revealed by Mantel tests, FSTvalues, exact tests and analyses of molecular variance, indicating that mussels from these regions are either at or close to panmixia. Similarly, patterns of genetic homogeneity were also found between the two Italian samples, whereas the observed genetic differentiation of the populations from Turkey and Croatia probably reflects the specific topographic and oceanographic conditions of these regions.
Aggression, DRD1 polymorphism, and lesion location in penetrating traumatic brain injury
Authors: Pardini Matteo , Krueger Frank , Hodgkinson Colin A. , Raymont Vanessa , Strenziok Maren , Amore Mario , Wassermann Eric M. , Goldman David , Grafman Jordan H.
Published: March 2014

Objective

This study evaluated whether structural brain lesions modulate the relationship between pathological aggression and the dopaminergic system in traumatic brain injury (TBI). While converging evidence suggests that different areas of the prefrontal cortex modulate dopaminergic activity, to date no evidence exists of a modulation of endogenous dopaminergic tone by lesion localization in penetrating TBI (pTBI).

Methods

This study included 141 male Caucasian veterans who suffered penetrating pTBI during their service in Vietnam and 29 healthy male Caucasian Vietnam veterans. Participants were genotyped for 3 functional single nucleotide polymorphisms (SNPs): dopamine receptor D1 (DRD1) rs686, dopamine receptor D2 (DRD2) rs4648317, and catechol-O-methyltransferase (COMT) Val158Met. Patients underwent brain CT scans and were divided into medial prefrontal cortex, lateral prefrontal cortex, and posterior cortex lesion groups. Long-term aggression levels were evaluated with the agitation/aggression subscale of the Neuropsychiatric Inventory.

Results

Our data showed that carriers of more transcriptionally active DRD1 alleles compared to noncarriers demonstrated greater aggression levels due to medial prefrontal cortex lesions but reduced aggression levels due to lateral prefrontal cortex lesions independently of DRD2 rs4648317 or COMT Val158Met genotypes.

Conclusions

Our results suggest that the relationship between pTBI-related aggression and the dopaminergic system is modulated by lesion location. Potentially lesion location could represent an easy-to-use, widely available, para-clinical marker to help in the development of an individualized therapeutic approach to pTBI-related pathological aggression.
Immunometabolism: the interface of immune and metabolic responses in disease
Authors: Schertzer Jonathan D , Steinberg Gregory R
Published: March 2014

Metabolism and pathogen defense are essential requirements for survival. Mounting an immune response requires major changes to metabolic processes, and immune mediators (such as cytokines) also dictate changes in metabolism, including endocrine regulation of substrate utilization. The April 2014 issue contains a Special Feature on Immunometabolism: The interface of immune and metabolic responses in disease. Further background information on this important topic is available through the accompanying web focus which links to related articles from across Nature Publishing Group.
A New Carbon Allotrope with Six-Fold Helical Chains in all-sp2 Bonding Networks
Authors: Wang Jian-Tao , Chen Changfeng , Wang Enge , Kawazoe Yoshiyuki
Published: March 2014

Using a recently developed approach to constructing covalent network structures from linear carbyne, we identify by ab initio calculations a new carbon allotrope in "Equation missing" ("Equation missing") symmetry that comprises six-fold helical chains with alternating sp2-type single and double bonds along the chains that are connected via zigzag benzene rings. This 6-fold carbene is characterized as a three-dimensional three-connected chiral crystalline modification of graphite. Phonon and electronic band calculations indicate that this new structure is dynamically stable and is a semiconductor with a band gap of 0.47 eV, in contrast to the semimetallic nature of graphite. Simulated x-ray diffraction patterns of the 6-fold carbene provide an excellent match to the previously unexplained distinct diffraction peak of a new carbon allotrope found in recent detonation experiments. These results establish a new carbon phase and offer insights into its outstanding structural and electronic properties.
B-doped carbon quantum dots as a sensitive fluorescence probe for hydrogen peroxide and glucose detection
Authors: Shan Xiaoyue , Chai Lujing , Ma Juanjuan , Qian Zhaosheng , Chen Jianrong , Feng Hui
Published: March 2014

Fluorescent B-doped carbon quantum dots (BCQDs) were used as a novel fluorescence sensing system for hydrogen peroxide and glucose detection.
Synthesis of a series of coordination polymers based on mixed ligands to tune the structural dimension
Authors: Cao Xinyu , Mu Bao , Huang Rudan
Published: March 2014

Schematic illustrating the 2D network of complex 1. Color code: yellow, Mn; cob2− ligand, red.
The thermodynamic characteristics of organic crystal growth by physical vapor transport: towards high-quality and color-tunable crystal preparation
Authors: Wang Huan , Zhao Yang , Xie Zengqi , Wang Huaiyuan , Wang Baohui , Ma Yuguang
Published: March 2014

Organic crystals grown at lower temperature have tighter molecular stacking, sharper diffraction peaks and higher quality.
Dynamics of actinyl ions in water: a molecular dynamics simulation study
Authors: Tiwari Surya Prakash , Rai Neeraj , Maginn Edward J.
Published: March 2014

The dynamics of actinyl ions (AnO2n+) in aqueous solutions is important not only for the design of advanced separation processes but also for understanding the fate of actinides in the environment.
Red electroluminescence of ruthenium sensitizer functionalized by sulfonate anchoring groups
Authors: Shahroosvand Hashem , Abbasi Parisa , Mohajerani Ezeddin , Janghouri Mohammad
Published: March 2014

We have synthesized five novel Ru(ii) phenanthroline complexes with an additional aryl sulfonate ligating substituent at the 5-position, as both photosensitizers for oxide semiconductor solar cells (DSSCs) and light emitting diodes (LEDs).
Fixation and recycling of nitrogen monoxide through carbonitrosation reactions
Authors: de Salas Cristina , Heinrich Markus R.
Published: March 2014

Nitrogen monoxide from oxygen-containing gas streams has been used for a variant of the Meerwein arylation to give oximes.
Reduced graphene oxides: the thinnest and most lightweight materials with highly efficient microwave attenuation performances of the carbon world
Authors: Wen B. , Wang X. X. , Cao W. Q. , Shi H. L. , Lu M. M. , Wang G. , Jin H. B. , Wang W. Z. , Yuan J. , Cao M. S.
Published: March 2014

r-GOs, as the thinnest and most lightweight materials of the carbon world, exhibit highly efficient microwave attenuation performances.
Dissociation of oxygen on pristine and nitrogen-doped carbon nanotubes: a spin-polarized density functional study
Authors: Srivastava Divya , Susi Toma , Borghei Maryam , Kari Laasonen
Published: March 2014

The oxygen adsorption energies for pristine and N-doped single-walled carbon nanotubes of different diameters.
Iodoarene-catalyzed fluorination and aminofluorination by an Ar-I/HF·pyridine/mCPBA system
Authors: Suzuki Satoru , Kamo Tomohiro , Fukushi Kazunobu , Hiramatsu Takaaki , Tokunaga Etsuko , Dohi Toshifumi , Kita Yasuyuki , Shibata Norio
Published: March 2014

We have developed the iodoarene-catalyzed fluorination of carbonyl compounds and intramolecular aminofluorination of ω-amino-alkenes using HF/mCPBA.
A CO2-stable reduction-tolerant Nd-containing dual phase membrane for oxyfuel CO2capture
Authors: Luo Huixia , Klande Tobias , Cao Zhengwen , Liang Fangyi , Wang Haihui , Caro Jürgen
Published: March 2014

We report a novel CO2-stable reduction-tolerant dual-phase oxygen transport membrane 40 wt% Nd0.6Sr0.4FeO3−δ–60 wt% Ce0.9Nd0.1O2−δ. This membrane material shows good reversibility of the oxygen permeation fluxes, good stability in a CO2atmosphere and under the harsh conditions of partial oxidation of methane to synthesis gas up to 950 °C.
A protein-based electrochemical biosensor for detection of tau protein, a neurodegenerative disease biomarker
Authors: Esteves-Villanueva Jose O. , Trzeciakiewicz Hanna , Martic Sanela
Published: March 2014

Tau–tau binding induced electrostatic and conformational changes on the surface modulating the charge transfer resistance.
Disposable solid-phase microextraction fiber coupled with gas chromatography-mass spectrometry for complex matrix analysis
Authors: Xu Jianqiao , He Shuming , Jiang Ruifen , Zhu Fang , Ruan Jingwen , Liu Hong , Luan Tiangang , Ouyang Gangfeng
Published: March 2014

A low-cost SPME fiber was prepared by mounting commercially available polydimethylsiloxane tubing on stainless steel wire with epoxy glue.
Three-component vesicle aggregation driven by adhesion interactions between Au nanoparticles and polydopamine-coated nanotubes
Authors: Jin Haibao , Zhou Yongfeng , Huang Wei , Zheng Yongli , Zhu Xinyuan , Yan Deyue
Published: March 2014

Large-scale and robust vesicle aggregates were obtained through three-component molecular recognition among cell-sized polymer vesicles, carbon nanotubes and Au nanoparticles driven by adhesion interactions between Au and polydopamine.
Bio-inspired synthesis of rare and unnatural carbohydrates and cyclitols through strain driven epimerization
Authors: Mohanrao Raja , Asokan Aromal , Sureshan Kana M.
Published: March 2014

Bio-inspired isomerization of carbohydrates and cyclitols to their rare and unnatural isomers, through strain-driven epimerization of trans-ketals to cis-ketals, is introduced.
Aminosilanetrithiol RSi(SH)3: an experimental and quantum-chemical study
Authors: Li Yan , Zhu Hongping , Andrada Diego M. , Frenking Gernot , Roesky Herbert W.
Published: March 2014

An aminosilanetrithiol is experimentally and quantum-chemically studied, which is the first example of a stable molecule containing three SH groups attached to one element.
Multimodal luminescent-magnetic boron nitride nanotubes@NaGdF4:Eu structures for cancer therapy
Authors: Li Xia , Hanagata Nobutaka , Wang Xuebin , Yamaguchi Maho , Yi Wei , Bando Yoshio , Golberg Dmitri
Published: March 2014

Boron nitride nanotubes@NaGdF4:Eu composites with core@shell structures were fabricated to trace and manipulate BNNTsin vitro.
Highly emissive water-soluble tetraazaperopyrenes as fluorescent markers
Authors: Hahn Lena , Öz Simin , Wadepohl Hubert , Gade Lutz H.
Published: March 2014

Synthesis of highly fluorescent water-soluble tetraazaperopyrene (TAPP) derivatives is reported; these act as fluorescent markers for cell nuclei.
A structurally-characterized NbCl5–NHC adduct
Authors: Bortoluzzi Marco , Ferretti Eleonora , Marchetti Fabio , Pampaloni Guido , Zacchini Stefano
Published: March 2014

The X-ray structure of 2a is the first one reported for a monodentate NHC–niobium compound and bears the highest oxidation state ever found for a metal centre in a transition metal halide–NHC adduct.
Modulating the solubility of sulfacetamide by means of cocrystals
Authors: Rajesh Goud N. , Khan Ronaq Ali , Nangia Ashwini
Published: March 2014

The antibacterial drug sulfacetamide was screened with pharmaceutically acceptable coformers to discover solid forms with low solubility. Cocrystals with INIC and CAF exhibited 0.64 and 0.68 times the IDR of the parent drug. SACT–CAF cocrystal with lower solubility and good stability is a potential candidate to increase the drug residence time at the site of action for improved therapeutic efficacy.
Positions of amino groups on ammonium salts tunes the conformations of crown ethers: crystal structures, Hirshfeld surfaces and spectroscopic studies
Authors: Luo Yang-Hui , Wu Dong-En , Song Wen-Tao , Ge Shu-Wang , Sun Bai-Wang
Published: March 2014

The position of the amino group on the ammonium salt plays a key role in the supramolecular structure and conformation of the crown ether.
Liquid-assisted vortex grinding supports the single-step solid-state construction of a [2.2]paracyclophane
Authors: Stojaković Jelena , Farris Brian S. , MacGillivray Leonard R.
Published: March 2014

We employ vortex grinding to generate a [2.2]paracyclophane in the organic solid state. The vortex grinding is aided with the addition of a small amount of liquid phase to facilitate topochemical [2 + 2] photodimerizations that generate the cyclophane stereoselectively and in up to quantitative yield. The use of the liquid phase increases the scope of the vortex method.
Origami paper-based fluidic batteries for portable electrophoretic devices
Authors: Chen Sung-Sheng , Hu Chih-Wei , Yu I-Fan , Liao Ying-Chih , Yang Jing-Tang
Published: March 2014

A manufacturing approach for paper-based fluidic batteries was developed based on the origami principle (three-dimension paper folding).
Total synthesis of lycorine-type alkaloids by cyclopropyl ring-opening rearrangement
Authors: Liu Dandan , Ai Long , Li Fan , Zhao Annan , Chen Jingbo , Zhang Hongbin , Liu Jianping
Published: March 2014

Anhydrocaranine, γ-lycorane and putative amarbellisine were synthesized based on a series reactions including a novel cyclopropyl ring-opening rearrangement.
“Click and go”: simple and fast folic acid conjugation
Authors: Trindade Alexandre F. , Frade Raquel F. M. , Maçôas Ermelinda M. S. , Graça Cátia , Rodrigues Catarina A. B. , Martinho José M. G. , Afonso Carlos A. M.
Published: March 2014

A novel approach for conjugation of folic acid is presented allowing for its quantitative conjugation with several types of molecules (fluorescent probes) and materials (polymers and silica) based on strain-promoted alkyne–azide cycloaddition, without the need for expensive chromatographic purifcation.
Improved hemicryptophane hosts for the stereoselective recognition of glucopyranosides
Authors: Schmitt Aline , Perraud Olivier , Payet Elina , Chatelet Bastien , Bousquet Benjamin , Valls Marion , Padula Daniele , Di Bari Lorenzo , Dutasta Jean-Pierre , Martinez Alexandre
Published: March 2014

Slight changes in the chiral environment of enantiopure hemicryptophanes improve the stereoselective recognition of α and β anomers of glucopyranosides.
The diene-transmissive hetero-Diels–Alder reaction of 2-vinyl α,β-unsaturated aldimines: stereoselective synthesis of hexahydroquinazolin-2-ones
Authors: Kobayashi Satoru , Kudo Kenji , Ito Ai , Hirama Satoru , Otani Takashi , Saito Takao
Published: March 2014

The tandem Diels–Alder methodology of cross-conjugated 1-azatrienes for synthesis of crossed bis-cycloadducts with high chemo-, regio- and stereoselectivities is described.
Water-promoted ortho-selective monohydroxymethylation of phenols in the NaBO2 system
Authors: Li Hui-Jing , Wu Ying-Ying , Wu Qin-Xi , Wang Rui , Dai Chun-Yang , Shen Zhi-Lun , Xie Cheng-Long , Wu Yan-Chao
Published: March 2014

Water-promoted ortho-selective monohydroxymethylation of phenols in the NaBO2 system generates salicyl alcohols in excellent yields.
Synthesis and evaluation of monophosphoryl lipid A derivatives as fully synthetic self-adjuvanting glycoconjugate cancer vaccine carriers
Authors: Zhou Zhifang , Mondal Mohabul , Liao Guochao , Guo Zhongwu
Published: March 2014

Monophosphoryl lipid A derivatives were used as both carrier molecules and built-in adjuvants to create fully synthetic self-adjuvanting glycoconjugate cancer vaccines.
Electronic transport behaviours of lead chalcogenide (PbE)n (E = S and Se) nanocluster junctions by ab initio simulation
Authors: Li Rong , Zhang Jianbing , Xu Yuanlan , Miao Xiangshui , Zhang Daoli
Published: March 2014

All investigated (PbS)n and (PbSe)n nanocluster-based molecular junctions show metallic behavior at low biases (−2 V, 2 V) while negative differential resistance (NDR) appears at a certain high bias range.
Acid-induced formation of hydrogen-bonded double helix based on chiral polyphenyl-bridged bis(2,2′-bipyridine) ligands
Authors: Sham Kiu-Chor , Yee Chi-Chung , Pan Yi , Lau Kai-Chung , Yiu Shek-Man , Kwong Hoi-Lun
Published: March 2014

Chiral polyphenyl-bridged bis(2,2′-bipyridine) ligands L2–4 give intense CD signals when protonated with tetrachloroferric acid or perchloric acid. X-ray crystal structure of [(L2)2H2](FeCl4)2 shows that a double-stranded helix stabilized by both interior and exterior hydrogen bonding is formed. Theoretical DFT calculations show that such stabilization exists in solution.
Solvothermal synthesis of magnetic copper nitride nanocubes with highly electrocatalytic reduction properties
Authors: Xi Pinxian , Xu Zhihong , Gao Daqiang , Chen Fengjuan , Xue Desheng , Tao Chun-Lan , Chen Zhong-Ning
Published: March 2014

Copper nitride (Cu3N) nanocubes prepared by an organic solvothermal approach exhibit excellent electrocatalytic activity toward the oxygen reduction reaction (ORR) and nitrobenzene reduction (NBR).
Chemical bonding in amorphous Si-coated carbon nanotubes as anodes for Li ion batteries: a XANES study
Authors: Zhou Jigang , Hu Yongfeng , Li Xiaolin , Wang Chongmin , Zuin Lucia
Published: March 2014

The Si–O–C bonding and its evolution upon electrochemical cycling in a Si-coated carbon nanotube anode are unveiled by X-ray absorption spectroscopy studies.
Ferroelectric domain morphology and temperature-dependent piezoelectricity of (K,Na,Li)(Nb,Ta,Sb)O3 lead-free piezoceramics
Authors: Yao Fang-Zhou , Yu Qi , Wang Ke , Li Qi , Li Jing-Feng
Published: March 2014

TEM and PFM studies revealed the intriguing domain morphology of (K,Na,Li)(Nb,Ta,Sb)O3 lead-free piezoelectric polycrystals. Temperature-dependent electrical properties in terms of piezoelectric coefficient d33 and normalized strain d33* were also investigated.
Facile hydrothermal synthesis of crystalline Ta2O5 nanorods, MTaO3 (M = H, Na, K, Rb) nanoparticles, and their photocatalytic behaviour
Authors: Gömpel Dorothea , Tahir Muhammad Nawaz , Panthöfer Martin , Mugnaioli Enrico , Brandscheid Robert , Kolb Ute , Tremel Wolfgang
Published: March 2014

Alkali metal tantalates are of interest for applications in photocatalysis as well as in high temperature resistance or capacitor dielectric materials.
Anodic electrodeposition of a porous nickel oxide–hydroxide film on passivated nickel foam for supercapacitors
Authors: Gu Lin , Wang Yewu , Lu Ren , Guan Liao , Peng Xinsheng , Sha Jian
Published: March 2014

A porous nickel oxide–hydroxide film is deposited on passivated 3D nickel foam by anodic electrodeposition for a high performance supercapacitor electrode.
Synthesis of water well-dispersed PEGylated iron oxide nanoparticles for MR/optical lymph node imaging
Authors: Yang Kyung Mo , Cho Hong-Il , Choi Hyuck Jae , Piao Yuanzhe
Published: March 2014

We reported the synthesis of highly water-stable iron oxide nanoparticles by a simple one-pot reaction.
Rare earth nanoprobes for functional biomolecular imaging and theranostics
Authors: Naczynski Dominik J. , Tan Mei Chee , Riman Richard E. , Moghe Prabhas V.
Published: March 2014

Schematic of our first-in-class system based on rare earth nanoprobes for real-time and multi-spectralin vivooptical SWIR imaging of tumors, organs, and vasculature.
The formation mechanism, improved photoluminescence and LED applications of red phosphor K2SiF6:Mn4+
Authors: Lv Lifen , Jiang Xianyu , Huang Shaoming , Chen Xi'an , Pan Yuexiao
Published: March 2014

The formation mechanism of red phosphor K2SiF6:Mn4+ free of manganese oxides has been discussed based on detailed experimental results. Significant improvements in the luminescence efficiency make it a good candidate for applications in “warm” white LEDs.
Bent-rod liquid crystal dimers: synthesis and mesomorphic properties
Authors: Sebastián Nerea , Gimeno Nélida , Vergara Jorge , López David O. , Serrano José Luis , Folcia César L. , de la Fuente M. Rosario , Ros M. Blanca
Published: March 2014

The mesomorphism of bent-rod dimers with a very long flexible linker strongly depends on the structure of the spacer and the rod-core.
Nitric oxide production by monocytes in children with OSA and endothelial dysfunction
Authors: Kheirandish-Gozal Leila , Wang Yang , Duggan Ryan C. , Harshan Vardhan Sindhuja , Tan Hui-Leng , Molero Ramirez Helena , Khalyfa Abdelnaby , Bhattacharjee Rakesh , Bandla Hari P.R. , Gozal David
Published: March 2014

OSA (obstructive sleep apnoea) is associated with a higher risk for alterations in post-occlusive hyperaemia, an eNOS (endothelial NO synthase)-dependent endothelial response. However, since not all children manifest endothelial dysfunction, we hypothesized that differences in circulating monocyte subsets and NO production may underlie the vascular phenotype in paediatric OSA. Matched pre-pubertal children with OSA with abnormal endothelial function (OSAab) and with normal endothelial function (OSAn), and controls (CO) were recruited. Peripheral blood mononuclear cells were subtyped into CD14+ and CD16+ cells, and NO production was assessed using flow cytometry. Endothelial dysfunction was defined as Tmax (time to reach maximal reperfusion) >45 s by laser Doppler flowmetry. A total of 11 OSAab, 12 OSAn and 12 CO-matched children completed the study. The OSAab group had increased CD16+ and decreased CD14+ cell numbers. They also had increased CX3CR1 (CX3C chemokine receptor 1) expression in CD16+ monocytes (P<0.01). Furthermore, monocytes from the OSAab group exhibited overall reduced NO production (787±71 compared with 1226±229 and 1089±116 median fluorescence intensity in the OSAn group and CO children respectively; P<0.01). Significant bivariate associations emerged between NO production, monocyte subsets, CX3CR1 in CD16+ monocytes, the CD14+/CD16+ ratio and Tmax. Thus OSA in children is associated with increased numbers of pro-inflammatory monocytes and reduced NO production in circulating monocytes that are closely associated with endothelial function.
Fish oil omega-3 fatty acids partially prevent lipid-induced insulin resistance in human skeletal muscle without limiting acylcarnitine accumulation
Authors: Stephens Francis B. , Mendis Buddhike , Shannon Chris E. , Cooper Scott , Ortori Catharine A. , Barrett David A. , Mansell Peter , Tsintzas Kostas
Published: March 2014

Acylcarnitine accumulation in skeletal muscle and plasma has been observed in numerous models of mitochondrial lipid overload and insulin resistance. Fish oil n3PUFA (omega-3 polyunsaturated fatty acids) are thought to protect against lipid-induced insulin resistance. The present study tested the hypothesis that the addition of n3PUFA to an intravenous lipid emulsion would limit muscle acylcarnitine accumulation and reduce the inhibitory effect of lipid overload on insulin action. On three occasions, six healthy young men underwent a 6-h euglycaemic–hyperinsulinaemic clamp accompanied by intravenous infusion of saline (Control), 10% Intralipid® [n6PUFA (omega-6 polyunsaturated fatty acids)] or 10% Intralipid®+10% Omegaven® (2:1; n3PUFA). The decline in insulin-stimulated whole-body glucose infusion rate, muscle PDCa (pyruvate dehydrogenase complex activation) and glycogen storage associated with n6PUFA compared with Control was prevented with n3PUFA. Muscle acetyl-CoA accumulation was greater following n6PUFA compared with Control and n3PUFA, suggesting that mitochondrial lipid overload was responsible for the lower insulin action observed. Despite these favourable metabolic effects of n3PUFA, accumulation of total muscle acylcarnitine was not attenuated when compared with n6PUFA. These findings demonstrate that n3PUFA exert beneficial effects on insulin-stimulated skeletal muscle glucose storage and oxidation independently of total acylcarnitine accumulation, which does not always reflect mitochondrial lipid overload.
Speech Sound Production in 2-Year-Olds Who Are Hard of Hearing
Authors: Ambrose Sophie E. , Unflat Berry Lauren M. , Walker Elizabeth A. , Harrison Melody , Oleson Jacob , Moeller Mary Pat
Published: March 2014

Purpose

The purpose of the study was to (a) compare the speech sound production abilities of 2-year-old children who are hard of hearing (HH) to children with normal hearing (NH), (b) identify sources of risk for individual children who are HH, and (c) determine whether speech sound production skills at age 2 were predictive of speech sound production skills at age 3.

Method

Seventy children with bilateral, mild-to-severe hearing loss who use hearing aids and 37 age- and socioeconomic status–matched children with NH participated. Children's speech sound production abilities were assessed at 2 and 3 years of age.

Results

At age 2, the HH group demonstrated vowel production abilities on par with their NH peers but weaker consonant production abilities. Within the HH group, better outcomes were associated with hearing aid fittings by 6 months of age, hearing loss of less than 45 dB HL, stronger vocabulary scores, and being female. Positive relationships existed between children's speech sound production abilities at 2 and 3 years of age.

Conclusion

Assessment of early speech sound production abilities in combination with demographic, audiologic, and linguistic variables may be useful in identifying HH children who are at risk for delays in speech sound production.
Current Opinions on Surgical Treatment of Fractures of the Condylar Head
Authors: Boffano Paolo , Benech Rodolfo , Gallesio Cesare , Arcuri Francesco , Benech Arnaldo
Published: March 2014

Treatment of mandibular condyle fractures is still controversial, with surgical treatment slowly becoming the preferred option. However, fractures of the condylar head (diacapitular fractures) are still treated conservatively at many institutions. Recently, more and more surgeons have begun to perform open treatment for diacapitular fractures because it allows to restore the anatomical position of the fragments and disc, it allows an immediate functional movement of the jaw, and avoid the ankylosis of the temporomandibular joint induced by the trauma. Several techniques have been proposed to reduce and fix fractures of the condylar head, such as standard bone screws, resorbable screws, resorbable pins, and cannulated lag screws. Therefore, the aim of this article is to review the literature about the surgical treatment of fractures of the condylar head to resume the current knowledge about open treatment of such fractures.
Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution
Authors: Wang Jinyang , Zhong Haimin , Feng Huajie , Qiu Wenda , Chen Liuping
Published: March 2014

The binary infinite dilute diffusion coefficients, $D_{12}^\infty$D12∞, of some alkylbenzenes (Ph-Cn, from Ph-H to Ph-C12) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO2) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-Cn/CO2 fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-Cn in scCO2 is significantly influenced by the structure of Ph-Cn solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-Cn in scCO2. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-Cn is the result of internal rotation of C-C single bond (σc-c) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-Cn with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ≥ 5) and long-chain Ph-Cn (n ≥ 4) in scCO2 are different.
A model study of sequential enzyme reactions and electrostatic channeling
Authors: Eun Changsun , Kekenes-Huskey Peter M. , Metzger Vincent T. , McCammon J. Andrew
Published: March 2014

We study models of two sequential enzyme-catalyzed reactions as a basic functional building block for coupled biochemical networks. We investigate the influence of enzyme distributions and long-range molecular interactions on reaction kinetics, which have been exploited in biological systems to maximize metabolic efficiency and signaling effects. Specifically, we examine how the maximal rate of product generation in a series of sequential reactions is dependent on the enzyme distribution and the electrostatic composition of its participant enzymes and substrates. We find that close proximity between enzymes does not guarantee optimal reaction rates, as the benefit of decreasing enzyme separation is countered by the volume excluded by adjacent enzymes. We further quantify the extent to which the electrostatic potential increases the efficiency of transferring substrate between enzymes, which supports the existence of electrostatic channeling in nature. Here, a major finding is that the role of attractive electrostatic interactions in confining intermediate substrates in the vicinity of the enzymes can contribute more to net reactive throughput than the directional properties of the electrostatic fields. These findings shed light on the interplay of long-range interactions and enzyme distributions in coupled enzyme-catalyzed reactions, and their influence on signaling in biological systems.
Electron correlations and two-photon states in polycyclic aromatic hydrocarbon molecules: A peculiar role of geometry
Authors: Aryanpour Karan , Shukla Alok , Mazumdar Sumit
Published: March 2014

We present numerical studies of one- and two-photon excited states ordering in a number of polycyclic aromatic hydrocarbon molecules: coronene, hexa-peri-hexabenzocoronene, and circumcoronene, all possessing D6h point group symmetry versus ovalene with D2h symmetry, within the Pariser-Parr-Pople model of interacting π-electrons. The calculated energies of the two-photon states as well as their relative two-photon absorption cross-sections within the interacting model are qualitatively different from single-particle descriptions. More remarkably, a peculiar role of molecular geometry is found. The consequence of electron correlations is far stronger for ovalene, where the lowest spin-singlet two-photon state is a quantum superposition of pairs of lowest spin triplet states, as in the linear polyenes. The same is not true for D6h group hydrocarbons. Our work indicates significant covalent character, in valence bond language, of the ground state, the lowest spin triplet state and a few of the lowest two-photon states in D2h ovalene but not in those with D6h symmetry.
Diffusion and spectroscopy of water and lipids in fully hydrated dimyristoylphosphatidylcholine bilayer membranes
Authors: Yang J. , Calero C. , Martí J.
Published: March 2014

Microscopic structure and dynamics of water and lipids in a fully hydrated dimyristoylphosphatidylcholine phospholipid lipid bilayer membrane in the liquid-crystalline phase have been analyzed with all-atom molecular dynamics simulations based on the recently parameterized CHARMM36 force field. The diffusive dynamics of the membrane lipids and of its hydration water, their reorientational motions as well as their corresponding spectral densities, related to the absorption of radiation, have been considered for the first time using the present force field. In addition, structural properties such as density and pressure profiles, a deuterium-order parameter, surface tension, and the extent of water penetration in the membrane have been analyzed. Molecular self-diffusion, reorientational motions, and spectral densities of atomic species reveal a variety of time scales playing a role in membrane dynamics. The mechanisms of lipid motion strongly depend on the time scale considered, from fast ballistic translation at the scale of picoseconds (effective diffusion coefficients of the order of 10−5 cm2/s) to diffusive flow of a few lipids forming nanodomains at the scale of hundreds of nanoseconds (diffusion coefficients of the order of 10−8 cm2/s). In the intermediate regime of sub-diffusion, collisions with nearest neighbors prevent the lipids to achieve full diffusion. Lipid reorientations along selected directions agree well with reported nuclear magnetic resonance data and indicate two different time scales, one about 1 ns and a second one in the range of 2–8 ns. We associated the two time scales of reorientational motions with angular distributions of selected vectors. Calculated spectral densities corresponding to lipid and water reveal an overall good qualitative agreement with Fourier transform infrared spectroscopy experiments. Our simulations indicate a blue-shift of the low frequency spectral bands of hydration water as a result of its interaction with lipids. We have thoroughly analyzed the physical meaning of all spectral features from lipid atomic sites and correlated them with experimental data. Our findings include a “wagging of the tails” frequency around 30 cm−1, which essentially corresponds to motions of the tail-group along the instantaneous plane formed by the two lipid tails, i.e., in-plane oscillations are clearly of bigger importance than those along the normal-to-the plane direction.
Defect-mediated relaxation in the random tiling phase of a binary mixture: Birth, death and mobility of an atomic zipper
Authors: Tondl Elisabeth , Ramsay Malcolm , Harrowell Peter , Widmer-Cooper Asaph
Published: March 2014

This paper describes the mechanism of defect-mediated relaxation in a dodecagonal square-triangle random tiling phase exhibited by a simulated binary mixture of soft discs in 2D. We examine the internal transitions within the elementary mobile defect (christened the “zipper”) that allow it to move, as well as the mechanisms by which the zipper is created and annihilated. The structural relaxation of the random tiling phase is quantified and we show that this relaxation is well described by a model based on the distribution of waiting times for each atom to be visited by the diffusing zipper. This system, representing one of the few instances where a well defined mobile defect is capable of structural relaxation, can provide a valuable test case for general theories of relaxation in complex and disordered materials.
Hydrogenation of O and OH on Pt(111): A comparison between the reaction rates of the first and the second hydrogen addition steps
Authors: Näslund L.-Å.
Published: March 2014

The formation of water through hydrogenation of oxygen on platinum occurs at a surprisingly low reaction rate. The reaction rate limited process for this catalytic reaction is, however, yet to be settled. In the present work, the reaction rates of the first and the second hydrogen addition steps are compared when hydrogen is obtained through intense synchrotron radiation that induces proton production in a water overlayer on top of the adsorbed oxygen species. A substantial amount of the produced hydrogen diffuses to the platinum surface and promotes water formation at the two starting conditions O/Pt(111) and (H2O+OH)/Pt(111). The comparison shows no significant difference in the reaction rate between the first and the second hydrogen addition steps, which indicates that the rate determining process of the water formation from oxygen on Pt(111) is neither the first nor the second H addition step or, alternatively, that both H addition steps exert rate control.
Optimization of magneto-resistive response of ion-irradiated exchange biased films through zigzag arrangement of magnetization
Authors: Trützschler Julia , Sentosun Kadir , Langer Manuel , Mönch Ingolf , Mattheis Roland , Fassbender Jürgen , McCord Jeffrey
Published: March 2014

Exchange coupled ferromagnetic-antiferromagnetic Ni81Fe19/Ir23Mn77 films with a zigzag alignment of magnetization are prepared by local ion irradiation. The anisotropic magneto-resistive behavior of the magnetic thin film structures is correlated to the magnetic structure and modeled. A unique uniaxial field sensitivity along the net magnetization alignment is obtained through the orthogonally modulated and magnetic domain wall stabilized magnetic ground state. Controlling local thin film magnetization distributions and, thus, the overall magnetization response opens unique ways to tailor the magneto-resistive sensitivity of functional magnetic thin film devices.
Intracellular performance of tailored nanoparticle tracers in magnetic particle imaging
Authors: Arami Hamed , Krishnan Kannan M.
Published: March 2014

Magnetic Particle Imaging (MPI) is a quantitative mass-sensitive, tracer-based imaging technique, with potential applications in various cellular imaging applications. The spatial resolution of MPI, in the first approximation, improves by decreasing the full width at half maximum (FWHM) of the field-derivative of the magnetization, dm/dH of the nanoparticle (NP) tracers. The FWHM of dm/dH depends critically on NPs’ size, size distribution, and their environment. However, there is limited information on the MPI performance of the NPs after their internalization into cells. In this work, 30 to 150 μg of the iron oxide NPs were incubated in a lysosome-like acidic buffer (0.2 ml, 20 mM citric acid, pH 4.7) and investigated by vibrating sample magnetometry, magnetic particle spectroscopy, transmission electron microscopy, and dynamic light scattering (DLS). The FWHM of the dm/dH curves of the NPs increased with incubation time and buffer to NPs ratio, consistent with a decrease in the median core size of the NPs from ∼20.1 ± 0.98 to ∼18.5 ± 3.15 nm. Further, these smaller degraded NPs formed aggregates that responded to the applied field by hysteretic reversal at higher field values and increased the FWHM. The rate of core size decrease and aggregation were inversely proportional to the concentration of the incubated NPs, due to their slower biodegradation kinetics. The results of this model experiment show that the MPI performance of the NPs in the acidic environments of the intracellular organelles (i.e., lysosomes and endosomes) can be highly dependent on their rate of internalization, residence time, and degradation.
Electric field controlled reversible magnetic anisotropy switching studied by spin rectification
Authors: Zhou Hengan , Fan Xiaolong , Wang Fenglong , Jiang Changjun , Rao Jinwei , Zhao Xiaobing , Gui Y. S. , Hu C.-M. , Xue Desheng
Published: March 2014

In this letter, spin rectification was used to study the electric field controlled dynamic magnetic properties of the multiferroic composite which is a Co stripe with induced in-plane anisotropy deposited onto a Pb(Mg1∕3Nb2∕3)O3-PbTiO3 substrate. Due to the coupling between piezoelectric and magnetoelastic effects, a reversible in-plane anisotropy switching has been realized by varying the history of the applied electric field. This merit results from the electric hysteresis of the polarization in the nonlinear piezoelectric regime, which has been proved by a butterfly type electric field dependence of the in-plane anisotropy field. Moreover, the electric field dependent effective demagnetization field and linewidth have been observed at the same time.