bluuebunny/crossref_metadata_2025 huggingface dataset:
Untersuchungen über die Beziehung zwischen Langperiode und Kettenlänge in Poly(äthylenoxyd)‐Kristallen
Authors: Calleja F. J. Baltá , Hosemann R. , Wilke W.
Published: September 2014

The study of annealed polyethylene oxide crystals grown from solution has been carried out in the molecular weight range where the transition from the extended chain conformation to the folded chain conformation was expected to occur. Both the variation of the long period with chain length and the chain orientation with respect to the vertical direction to the crystal lamellae plane have been investigated. The value of the long period for crystals grown in p‐xylene closely corresponds to that calculated for a 72 helix. During annealing no change of the long period takes place due to the effect of hydrogen bonds of the endgroups.
Influence de la Stereorégularite des Chaînes sur les Transitions du Polyméthacrylate de Méthyle
Authors: Wittmann J. C. , Kovacs A. J.
Published: September 2014

Dilatométric studies on five PMM samples of different tacticities show generally three transition ranges between −35 and 150°C. The main glass transition temperature depends on the relative proportion of the iso‐ or syndiotactic segments. The secondary transition, located around 60°C., seems to be related to the presence of heterotactic segments. The third transition range, common to all the five samples, located around 0°C., may be attributed tentatively to the freezing in of the ester side groups.
Organic semiconductors: Donor—acceptor complexes of conjugated bases with a repeating structural unit
Authors: Honzl J. , Ulbert K. , Hádek V. , Tlusťáková M. , Metalová M.
Published: September 2014

Iodine complexes of some mono‐ and diamino derivatives of diphenylamine, N,N′‐diphenyl‐p‐phenylenediamine and 4,4′‐bis(phenylamino)‐diphenylamine and their N‐methyl derivatives were prepared and their conductivity, thermoelectric power, activation energy of conductivity, and the spin concentration in the solid state were investigated. For complexes prepared from the bases with a repeating unit in the chain, the conductivity increased in most cases with the length of the chain. Complexes of bases with methylated nitrogens were more stable and had a smaller conductivity than analogous complexes prepared from nonmethylated bases. Conductivity and spin concentration in most of the substances investigated were reproducible in different batches of the same compound, and were only slightly influenced by aging and the presence of oxygen. The activation energy of conductivity and thermoelectric power exhibit larger variations. The most conductive compound had a specific conductivity of 2 × 10−1 Ω−1 cm.−1.
The effect of applied pressure in some solid state polymerizations
Authors: Fydelor P. J. , Charlesby A.
Published: September 2014

We report some preliminary observations on the influence of applied pressures up to 90,000 psi on some gamma‐initiated, solid state polymerizations. Four monomers have been studied: acrylamide and methacrylamide, both of which are believed to yield atactic polymer but show markedly different rates of reaction in the solid state, and some crystalline modifications of calcium acrylate and barium methacrylate, which can give rise to stereoregular polymer. The rate of polymerization of the former monomers is reduced by the application of pressure but this rate is substantially increased for the metal salts. These results are discussed with reference to the possible polymerization mechanisms.
Mechanisms of reinforcement of silicone rubbers crosslinked by radiation
Authors: Charlesby A. , Morris J. , Montague P.
Published: September 2014

The tensile strengths and elastic moduli of elastomers can be greatly influenced by the presence of fine particles such as carbon black or silica. This reinforcement can be due to either physical or chemical processes. The use of radiation to provide crosslinks in such systems permits the mechanism of this reinforcement to be studied. The results of some experiments on physical properties, gelation, and swelling behavior for a series of mixtures in dimethylsiloxane polymer are given. An extension to model compounds of low molecular weight allows the chemical bonding effects to be measured in the absence of geometrical inhibition arising from a network structure.
Structure of copolymers of polyacrylic acid grafted on ethylene propylene elastomers as determined by chemical/physical methods
Authors: Crugnola A. , Pegoraro M. , Severini F.
Published: September 2014

The raw product obtained from the emulsion polymerization of acrylic acid and ethylene–propylene copolymer is subjected to extraction to remove the polyacrylic acid homo‐polymer and the unreacted ethylene‐propylene copolymer. The residue is essentially the grafted copolymer. A determination of the force/temperature coefficient (∂f/∂T)I revealed that this material has the apparent properties of a vulcanized elastomer. We sought to single out the nature of the physical and chemical ties that are the cause of this behavior. We found that the material is heterophasic and that the intermolecular bonds are found in the phase constituted of polyacrylic acid; these bonds are of a physical nature (hydrogen bonding) and of a chemical nature. The latter are only present if the molding is carried out at sufficiently high temperatures. Intermolecular bonds have been recognized as resulting from a dehydration of the carboxyls with consequent formation of anhydride, and also from a complicated reaction involving a partial degradation of the polyacrylic acid.
Polyaddition and polycondensation. Substitution effects in polycondensation systems
Authors: Aldersley J. W. , Gordon M.
Published: September 2014

Deviations occur from the classical postulate that all pairs of functionalities in a condensation reaction have equal rates of engaging in bond formation or bond breakage. In so‐called first‐shell substitution effects, which can be treated most readily, the rates involving functionalities X and Y are influenced at most by the existence or absence of other links borne by the two units to which X and Y are directly attached. Quantitative analyses are made of data on melamine and urea‐formaldehyde systems in terms of first‐shell substitution effects.
The molecular conformation of isotactic poly (methyl methacrylate)
Authors: Coiro V. M. , De Santis P. , Liquori A. M. , Mazzarella L.
Published: September 2014

The molecular conformation of isotactic poly(methyl methacrylate) (PMMA) has been investigated without considering the mode of molecular packing in the crystal lattice. The analysis has been carried out on the basis of the interpretation of the x‐ray fiber diagram with the aid of the Fourier transform method. The molecular conformation is helical, with a monomer repeat on the fiber axis equal to 2.11 A. The best agreement between the experimental x‐ray diffraction pattern and the cylindrically averaged optical Fourier transform was obtained for a helix with five monomeric units per turn.
Carhorane polymers
Authors: Gregor V. , Plešek J. , Heřmánek S.
Published: September 2014

Monomers were prepared of substituted methacryloyloxymethyl earboranes and submitted to radical polymerization. From derivatives bearing other substituents than hydrogen on the carbon atoms in the carborane skeleton, linear polymers were obtained. Crosslinked polymers always result from carboranes, substituted on one carbon atom only. Obviously, crosslinking is the result of an interaction of the CH bond in the carborane skeleton with the growing chain of methacrylate groups.
Infrared spectra of polycarbohydrates and their model systems
Authors: Zhbankov R. G.
Published: September 2014

The relationship of the infrared spectra of polycarbohydrates with their specific structural properties investigated with various model systems, for example, mono‐, di‐saccharides, etc., is discussed.

Obtaining the carbohydrate spectra at the temperature of liquid nitrogen has allowed to split the OR group band into distinct components and to find out peculiarities of their low‐temperature shift, and to study the relationship of OR group hydrogen bond with the configuration of certain hydroxyls more thoroughly. Due to the considerable difference in the low‐temperature shift of OR group bands in the probable frequency ranges of intra‐ and intermolecular R bonds have been established as 3350‐3560 cm.−1 and 3100‐3450 cm.−1, respectively. The frequencies and intensities of OR group bands inserted in the H bond are observed to depend strongly upon the configuration of separate hydroxyl groups, suggesting a considerable interaction between the hydroxyls of the pyranose unit. The obtained results furnish ample grounds to conclude that the frequency of OR groups inserted in the hydrogen bond is detennined not only by the energy of the R bond but by the interaction ring, depending on the configuration of separate OR groups.

The establishment of a relationship between the mutual spatial arrangement of CR groups and the spectrum in the 800–950 cm.−1 region allowed us to determine the frequency intervals specific for the combinations of axial (A) and equatorial (E) CR groups EA for 810–855 cm.−1; AE for 860–855 cm,−1; AA for 885–920 cm.−1. This allows us to predict the appearance of possible frequencies in the considered region in the process of conformation transitions of the pyranose ring.

The investigation of mono‐, di‐, and polysaccharide spectra in the region of CH2 group deformation vibrations and calculation of the potential function of CR2OH group inner rotations permitted us to base the essential possibility of the existence of CR2OH group rotation isomers in carbohydrates and their polymers. The investigation of the spectral feature of crystalline cellulose triesters and triethers has been carried out. It is shown that their spectra are characterized by: an intensity increase of all or the majority of the absorption bands; the selective intensity increase of separate bands; and the appearance of new absorption bands. The intensity increase for many absorption bands is explained by the prevalence of certain types of rotation isomers and the appearance of new bands by the intermolecular interaction in crystals.
Fractionation of polypropylene glycols in the molecular weight range of 1200–2400 using a novel apparatus
Authors: Frank W. A. , Kutsche H. D.
Published: September 2014

Compounds of polypropylene glycols are used for testing the distillability of thermally very unstable substances. By means of these compounds it is demonstrated that it is possible to design molecular distilling apparatus which allows the distillation of substances that are by far more sensitive than hitherto. This was made possible by a rotation principle, which not only fulfills the other requirements of high‐vacuum distillation but also avoids catalytic effects during the distilling process.
Polymerization of ethylene glycol monomethacrylate in the presence of solvents
Authors: Wichterle O. , Chromeček R.
Published: September 2014

Hydrophilic gels have been prepared by polymerization of glycol methacrylate monoesters in the range of very low diester concentrations. The monomer mixture has been diluted with various solvents and the range has been investigated, in which swelling is independent of the dilution of the monomer mixture on polymerization. The quality of the gel is independent of the concentration and character of the solvent used in polymerization in a very broad range.
Modulating Potential of L‐Sulforaphane in the Expression of Cytochrome P450 to Identify Potential Targets for Breast Cancer Chemoprevention and Therapy Using Breast Cell Lines
Authors: Licznerska Barbara , Szaefer Hanna , Matuszak Iwona , Murias Marek , Baer‐Dubowska Wanda
Published: September 2014

The L‐sulforaphane (SFN) component of broccoli sprout showed anticancer activity in several preclinical studies including breast cancer. Estrogens are considered major risk factors in breast carcinogenesis. The aim of this study was to evaluate the effect of SFN on the expression of cytochrome P450 involved in the estrogen metabolism in breast cancer cell lines MCF7 and MDA‐MB‐231 and in non‐tumorigenic MCF10A cell line. The expression of CYP19, CYP1A1, 1A2, 1B1 was determined at the transcript and protein levels. There were found some remarkable differences in the effect of SFN at a dose of 5 µmol/L on CYP19 expression: in ER(+) MCF7 significant reduction, in ER(−) MDA‐MB‐231 an increased expression and unchanged expression in MCF10A cell line. The effect of SFN on CYPs (1A1, 1A2, 1B1) involved in estrogen catabolism was to a lesser extent dependent on breast cell line. The slightly reduced CYP1A1 protein level was observed in all cell lines tested. An increased level of CYP1A2 and decreased level of CYP1B1 expression were found in MCF10A. These results indicate that the naturally occurring L isomer of SFN may affect the expression of P450s involved in estrogen metabolism. This effect may contribute to the anticancer activity of SFN in breast tissue. Copyright © 2014 John Wiley & Sons, Ltd.
Atmospheric circulation evolution related to desert‐dust episodes over the Mediterranean
Authors: Gkikas A. , Houssos E. E. , Lolis C. J. , Bartzokas A. , Mihalopoulos N. , Hatzianastassiou N.
Published: September 2014

Cases of atmospheric circulation evolution favouring the occurrence of desert aerosol episodes (DAEs) over the broader Mediterranean region were investigated using an objective and dynamic algorithm, with daily satellite data for the period 2000–2013. After identifying strong and extreme DAEs, at a 1°×1°
geographical‐cell level, 255 dust aerosol episode days (DAEDs) and 148 cases of consecutive DAEDs, namely desert aerosol episode cases (DAECs), are defined. For each DAEC, the evolution of the lower tropospheric circulation 1 and 2 days before, during the initiation and after the cessation of the DAEC, is considered. S‐mode factor analysis and k‐means cluster analysis are applied on mean sea‐level pressure and 700 hPa geopotential height fields obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) Reanalysis Project, classifying the 148 cases of atmospheric‐circulation evolution into six homogeneous and discrete clusters. The mean intra‐annual variation of the DAECs reveals a primary maximum in May (18.9%), and their mean annual number is equal to 11.4 DAECs. On a seasonal basis, the highest percentage of the DAECs is found in spring (51.4%). Maximum duration of the DAECs is 7 days, with 58.8% lasting 1 day. Annually, the mean monthly number of the DAEs varies from 35.8 (September) to 58.0 (April). The western parts of the Mediterranean are affected by the DAEs when cyclonic conditions prevail in the western Mediterranean and northwestern Africa. In contrast, the central and eastern parts of the study region are affected by dust storms when a low‐pressure system in the central Mediterranean or central Europe and an anticyclone in the eastern Mediterranean prevail. As to the mean regional intensity (aerosol optical depth at 550 nm) the strong DAEs vary from 0.67 to 0.77, while the extremes vary from 1.14 to 2.06. Generally, strong DAEs are more frequent than extremes (in five out of six clusters).
Simple approach to derivatization of alcohols and phenols for the analysis by matrix(surface)‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Borisov Roman S. , Zhilyaev Dmitrii I. , Polovkov Nikolai Yu. , Zaikin Vladimir G.
Published: September 2014

RATIONALE

Direct analysis of hydroxyl‐containing compounds by matrix‐assisted laser desorption/ionization (MALDI) mass spectrometry (MS) methods is not always possible due to the neutral character of analytes. The suggested fixed‐charge derivatization may increase the ionization efficiency for various alcohols and phenols in specific matrix‐ and surface‐activated LDI conditions.

METHODS

Aliphatic and steroid alcohols, as well as chlorophenols, were converted into various ammonioacetyl derivatives, containing a covalently bonded charged group, by reaction with bromoacetyl chloride and amine‐type compounds such as triethylamine, pyridine or quinoline. The derivatives are suitable for MALDI‐time‐of‐flight (TOF)MS analysis.

RESULTS

Triethylammoniumacetyl, pyridyliumacetyl and quinoliniumacetyl derivatives were prepared from aliphatic alcohols, some sterols and chlorinated phenols in one stage with quantitative yields. The derivatives produced characteristic MALDI and SALDI mass spectra.

CONCLUSIONS

The suggested derivatization approach for the modification of alcohols is simple and does not require any expensive reagents. The derivatives include a fixed charge and produce intense signals in MALDI (preferentially non‐acidic matrices) and matrix‐free SALDI (nanostructured target) conditions. Corresponding mass spectra are suitable for the determination of molecular mass and profiling of alcohols. Copyright © 2014 John Wiley & Sons, Ltd.
Ambient analysis of leachable compounds from single‐use bioreactors with desorption electrospray ionization time‐of‐flight mass spectrometry
Authors: Liu Jian , Kennedy Joseph H. , Ronk Michael , Marghitoiu Liliana , Lee Hans , Nashed‐Samuel Yasser
Published: September 2014

RATIONALE

Trace levels of bis(2,4‐di‐tert‐butylphenyl)phosphate (BdtbPP) leaching from single‐use bioreactors (SUBs) were recently found to be highly detrimental to mammalian cell growth. The traditional approach to detect the leachable requires time‐consuming solvent extraction of SUBs. To assist the qualification of SUBs and/or their manufacturing raw materials in biopharmaceutical development and manufacturing, it is essential to develop a rapid and sensitive analytical approach for detecting this leachable and related compounds, which is described in this study.

METHODS

Native films from several commercially available SUBs were directly examined by desorption electrospray ionization (DESI) time‐of‐flight mass spectrometry (TOFMS) without sample preparation. As a comparison, the same SUBs were also analyzed by high‐performance liquid chromatography (HPLC)/ultraviolet (UV) following the solvent extraction.

RESULTS

With a suitable spray solvent selected in this study, DESI‐TOFMS enabled rapid and sensitive detection of leachable compounds directly from SUBs. Accurate mass measurement from TOFMS allowed ready identification of BdtbPP, its parent analog compound, and other polymer components in the SUBs from their protonated surrogates. The relative abundances of BdtbPP in different SUBs measured by DESI‐TOFMS exhibited good correlation with those from the traditional extraction‐based approach with HPLC/UV.

CONCLUSIONS

A rapid and sensitive approach was developed for direct detection of BdtbPP and other leachables from SUBs using DESI‐TOFMS. The results are in high accordance with those from conventional approaches, which indicates the usefulness of the proposed method as a qualification tool for SUBs in biopharmaceutical development and also its great potential in the analysis of extractables/leachables in a wide variety of materials, process components, devices and containers used in the pharmaceutical industry. Copyright © 2014 John Wiley & Sons, Ltd.
GUMBOS matrices of variable hydrophobicity for matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Al Ghafly Hashim , Siraj Noureen , Das Susmita , Regmi Bishnu P. , Magut Paul K. S. , Galpothdeniya Waduge Indika S. , Murray Kermit K. , Warner Isiah M.
Published: September 2014

RATIONALE

Detection of hydrophobic peptides remains a major obstacle for matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). This stems from the fact that most matrices for MALDI are hydrophilic and therefore have low affinities for hydrophobic peptides. Herein, 1‐aminopyrene (AP) and AP‐derived group of uniform materials based on organic salts (GUMBOS) as novel matrices for MALDI‐MS analyses of peptides were investigated for hydrophobic and hydrophilic peptides.

METHODS

A number of solid‐phase AP‐based GUMBOS are synthesized with variable hydrophobicity simply by changing the counterions. Structures were confirmed by use of 1H NMR and electrospray ionization mass spectrometry (ESI‐MS). 1‐Octanol/water partition coefficients (Ko/w) were used to measure the hydrophobicity of the matrices. A dried‐droplet method was used for sample preparation. All spectra were obtained using a MALDI‐TOF mass spectrometer in positive ion reflectron mode.

RESULTS

A series of AP‐based GUMBOS was synthesized including [AP][chloride] ([AP][Cl]), [AP][ascorbate] ([AP][Asc]) and [AP][bis(trifluoromethane)sulfonimide] ([AP][NTf2]). The relative hydrophobicities of these compounds and α‐cyano‐4‐hydroxycinnamic acid (CHCA, a common MALDI matrix) indicated that AP‐based GUMBOS can be tuned to be much more hydrophobic than CHCA. A clear trend is observed between the signal intensities of hydrophobic peptides and hydrophobicity of the matrix.

CONCLUSIONS

MALDI matrices of GUMBOS with tunable hydrophobicities are easily obtained simply by varying the counterion. We have found that hydrophobic matrix materials are very effective for MALDI determination of hydrophobic peptides and, similarly, the more hydrophilic peptides displayed greater intensity in the more hydrophilic matrix. Copyright © 2014 John Wiley & Sons, Ltd.
A Situationally Aware Voice‐commandable Robotic Forklift Working Alongside People in Unstructured Outdoor Environments
Authors: Walter Matthew R. , Antone Matthew , Chuangsuwanich Ekapol , Correa Andrew , Davis Randall , Fletcher Luke , Frazzoli Emilio , Friedman Yuli , Glass James , How Jonathan P. , Jeon Jeong hwan , Karaman Sertac , Luders Brandon , Roy Nicholas , Tellex Stefanie , Teller Seth
Published: September 2014

One long‐standing challenge in robotics is the realization of mobile autonomous robots able to operate safely in human workplaces, and be accepted by the human occupants. We describe the development of a multiton robotic forklift intended to operate alongside people and vehicles, handling palletized materials within existing, active outdoor storage facilities. The system has four novel characteristics. The first is a multimodal interface that allows users to efficiently convey task‐level commands to the robot using a combination of pen‐based gestures and natural language speech. These tasks include the manipulation, transport, and placement of palletized cargo within dynamic, human‐occupied warehouses. The second is the robot's ability to learn the visual identity of an object from a single user‐provided example and use the learned model to reliably and persistently detect objects despite significant spatial and temporal excursions. The third is a reliance on local sensing that allows the robot to handle variable palletized cargo and navigate within dynamic, minimally prepared environments without a global positioning system. The fourth concerns the robot's operation in close proximity to people, including its human supervisor, pedestrians who may cross or block its path, moving vehicles, and forklift operators who may climb inside the robot and operate it manually. This is made possible by interaction mechanisms that facilitate safe, effective operation around people. This paper provides a comprehensive description of the system's architecture and implementation, indicating how real‐world operational requirements motivated key design choices. We offer qualitative and quantitative analyses of the robot operating in real settings and discuss the lessons learned from our effort.
Efficient gene editing in adult mouse livers via adenoviral delivery of CRISPR/Cas9
Authors: Cheng Ranran , Peng Jin , Yan Yonghong , Cao Peili , Wang Jiewei , Qiu Chen , Tang Lichun , Liu Di , Tang Li , Jin Jianping , Huang Xingxu , He Fuchu , Zhang Pumin
Published: September 2014

We developed an adenovirus‐based CRISPR/Cas9 system for gene editing in vivo. In the liver, we demonstrated that the system could reach the level of tissue‐specific gene knockout, resulting in phenotypic changes. Given the wide spectrum of cell types susceptible to adenoviral infection, and the fact that adenoviral genome rarely integrates into its host cell genome, we believe the adenovirus‐based CRISPR/Cas9 system will find applications in a variety of experimental settings.
Differential contribution of the Fanconi anemia‐related proteins to repair of several types of DNA damage in cultured silkworm cells
Authors: Sugahara Ryohei , Mon Hiroaki , Lee Jae Man , Shiotsuki Takahiro , Kusakabe Takahiro
Published: September 2014

The silkworm Fanconi anemia (FA) pathway is required for normal cellular resistance to mitomycin C (MMC) in silkworms, but little is known about the requirement for repair of other types of DNA damage. Here we report that silkworm cells deficient for FA proteins FancD2 and FancM exhibit normal sensitivities to hydroxyurea (HU) and camptothecin (CPT), although FancM‐dependent FancD2 monoubiquitination is induced upon these treatments. Similar results were observed in cells depleted for Rmi1 and Mhf1, which interact with the FancM protein. We also found that Rad51‐knockdown cells exhibited normal sensitivity to HU despite induction of double‐strand breaks by HU treatment.
Light‐induced switching of HAMP domain conformation and dynamics revealed by time‐resolved EPR spectroscopy
Authors: Klose Daniel , Voskoboynikova Natalia , Orban-Glass Ioan , Rickert Christian , Engelhard Martin , Klare Johann P. , Steinhoff Heinz-Jürgen
Published: September 2014

HAMP domains are widely abundant signaling modules. The putative mechanism of their function comprises switching between two distinct states. To unravel these conformational transitions, we apply site‐directed spin labeling and time‐resolved EPR spectroscopy to the phototactic receptor/transducer complex NpSRII/NpHtrII. We characterize the kinetic coupling of NpHtrII to NpSRII along with the activation period of the transducer and follow the transient conformational signal. The observed transient shift towards a more compact state of the HAMP domain upon light‐activation agrees with structure‐based calculations. It thereby validates the two modeled signaling states and integrates the domain's dynamics into the current model.
Chaperone‐mediated reversible inhibition of the sarcomeric myosin power stroke
Authors: Nicholls Paul , Bujalowski Paul J. , Epstein Henry F. , Boehning Darren F. , Barral José M. , Oberhauser Andres F.
Published: September 2014

Molecular chaperones are required for successful folding and assembly of sarcomeric myosin in skeletal and cardiac muscle. Here, we show that the chaperone UNC‐45B inhibits the actin translocation function of myosin. Further, we show that Hsp90, another chaperone involved in sarcomere development, allows the myosin to resume actin translocation. These previously unknown activities may play a key role in sarcomere development, preventing untimely myosin powerstrokes from disrupting the precise alignment of the sarcomere until it has formed completely.
An inviscid modal interpretation of the ‘lift-up’ effect
Authors: Roy Anubhab , Subramanian Ganesh
Published: September 2014

In this paper, we give a modal interpretation of the lift-up effect, one of two well-known mechanisms that lead to an algebraic instability in parallel shearing flows, the other being the Orr mechanism. To this end, we first obtain the two families of continuous spectrum modes that make up the complete spectrum for a non-inflectional velocity profile. One of these families consists of modified versions of the vortex-sheet eigenmodes originally found by Case (Phys. Fluids, vol. 3, 1960, pp. 143–148) for plane Couette flow, while the second family consists of singular jet modes first found by Sazonov (Izv. Acad. Nauk SSSR Atmos. Ocean. Phys., vol. 32, 1996, pp. 21–28), again for Couette flow. The two families are used to construct the modal superposition for an arbitrary three-dimensional distribution of vorticity at the initial instant. The so-called non-modal growth that underlies the lift-up effect is associated with an initial condition consisting of rolls, aligned with the streamwise direction, and with a spanwise modulation (that is, a modulation along the vorticity direction of the base-state shearing flow). This growth is shown to arise from an appropriate superposition of the aforementioned continuous spectrum mode families. The modal superposition is then generalized to an inflectional velocity profile by including additional discrete modes associated with the inflection points. Finally, the non-trivial connection between an inviscid eigenmode and the viscous eigenmodes for large but finite Reynolds number, and the relation between the corresponding modal superpositions, is highlighted.
Weak turbulence theory for rotating magnetohydrodynamics and planetary flows
Authors: Galtier Sébastien
Published: September 2014

A weak turbulence theory is derived for magnetohydrodynamics (MHD) under rapid rotation and in the presence of a uniform large-scale magnetic field which is associated with a constant Alfvén velocity $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}{\boldsymbol {b}}_{{0}}$. The angular velocity ${\boldsymbol{\Omega}}_{{0}}$ is assumed to be uniform and parallel to ${\boldsymbol {b}}_{{0}}$. Such a system exhibits left and right circularly polarized waves which can be obtained by introducing the magneto-inertial length $d \equiv b_0/\varOmega _0$. In the large-scale limit ($kd \to 0$, with $k$ being the wavenumber) the left- and right-handed waves tend to the inertial and magnetostrophic waves, respectively, whereas in the small-scale limit ($kd \to + \infty $) pure Alfvén waves are recovered. By using a complex helicity decomposition, the asymptotic weak turbulence equations are derived which describe the long-time behaviour of weakly dispersive interacting waves via three-wave interaction processes. It is shown that the nonlinear dynamics is mainly anisotropic, with a stronger transfer perpendicular than parallel to the rotation axis. The general theory may converge to pure weak inertial/magnetostrophic or Alfvén wave turbulence when the large- or small-scale limits are taken, respectively. Inertial wave turbulence is asymptotically dominated by the kinetic energy/helicity, whereas the magnetostrophic wave turbulence is dominated by the magnetic energy/helicity. For both regimes, families of exact solutions are found for the spectra, which do not correspond necessarily to a maximal helicity state. It is shown that the hybrid helicity exhibits a cascade whose direction may vary according to the scale $k_f$ at which the helicity flux is injected, with an inverse cascade if $k_fd < 1$ and a direct cascade otherwise. The theory is relevant to the magnetostrophic dynamo, whose main applications are the Earth and the giant planets, such as Jupiter and Saturn, for which a small (${\sim }10^{-6}$) Rossby number is expected.
Spectral analogues of the law of the wall, the defect law and the log law
Authors: Zúñiga Zamalloa Carlo , Ng Henry Chi-Hin , Chakraborty Pinaki , Gioia Gustavo
Published: September 2014

Unlike the classical scaling relations for the mean-velocity profiles of wall-bounded uniform turbulent flows (the law of the wall, the defect law and the log law), which are predicated solely on dimensional analysis and similarity assumptions, scaling relations for the turbulent-energy spectra have been informed by specific models of wall turbulence, notably the attached-eddy hypothesis. In this paper, we use dimensional analysis and similarity assumptions to derive three scaling relations for the turbulent-energy spectra, namely the spectral analogues of the law of the wall, the defect law and the log law. By design, each spectral analogue applies in the same spatial domain as the attendant scaling relation for the mean-velocity profiles: the spectral analogue of the law of the wall in the inner layer, the spectral analogue of the defect law in the outer layer and the spectral analogue of the log law in the overlap layer. In addition, as we are able to show without invoking any model of wall turbulence, each spectral analogue applies in a specific spectral domain (the spectral analogue of the law of the wall in the high-wavenumber spectral domain, where viscosity is active, the spectral analogue of the defect law in the low-wavenumber spectral domain, where viscosity is negligible, and the spectral analogue of the log law in a transitional intermediate-wavenumber spectral domain, which may become sizable only at ultra-high$\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}\mathit{Re}_{\tau }$), with the implication that there exist model-independent one-to-one links between the spatial domains and the spectral domains. We test the spectral analogues using experimental and computational data on pipe flow and channel flow.
Pressure forces on sediment particles in turbulent open-channel flow: a laboratory study
Authors: Amir Mohammad , Nikora Vladimir I. , Stewart Mark T.
Published: September 2014

An experimental investigation into the fluctuating pressure acting on sediment particles on the bed of an open-channel flow was carried out in a large laboratory flume for a range of flow depths and bed slopes. The pressure measurements were made using 23 spherical particles instrumented with differential pressure sensors. These measurements were complemented with simultaneous measurements of the velocity field using high-resolution stereoscopic particle image velocimetry. The pressure statistics show that the standard deviations of the drag and lift fluctuations vary from 2.0 to 2.6 and from 2.5 to 3.4 times the wall shear stress, respectively, and are dependent on relative submergence and flow Reynolds number. The skewness is positive for the drag fluctuations and negative for the lift fluctuations. The kurtosis values of both drag and lift fluctuations increase with particle submergence. The two-particle correlation between drag and lift fluctuations is found to be relatively weak compared to the two-point drag–drag and lift–lift correlations. The pressure cross-correlations between particles separated in the longitudinal direction exhibit maxima at certain time delays corresponding to the convection velocities varying from 0.64 to 0.72 times the bulk flow velocity, being very close to the near-bed eddy convection velocities. The temporal autocorrelation of drag fluctuations decays much faster than that for the lift fluctuations; as a result, the temporal scales of lift fluctuations are 3–6 times that of drag fluctuations. The spatial and temporal scales of both drag and lift fluctuations show dependence on flow depth and bed slope. The spectral behaviour of both drag and lift fluctuations is also assessed. A $\def \xmlpi #1{}\def \mathsfbi #1{\boldsymbol {\mathsf {#1}}}\let \le =\leqslant \let \leq =\leqslant \let \ge =\geqslant \let \geq =\geqslant \def \Pr {\mathit {Pr}}\def \Fr {\mathit {Fr}}\def \Rey {\mathit {Re}}f^{-11/3}$ slope is observed for the spectra of the drag fluctuations over the majority of the frequency range, whereas the lift spectra suggest two scaling ranges, following a $f^{-11/3}$ slope at high frequencies and $f^{-5/3}$ behaviour at lower frequencies.
Parametric subharmonic instability of internal waves: locally confined beams versus monochromatic wavetrains
Authors: Karimi Hussain H. , Akylas T. R.
Published: September 2014

Internal gravity wavetrains in continuously stratified fluids are generally unstable as a result of resonant triad interactions which, in the inviscid limit, amplify short-scale perturbations with frequency equal to one half of that of the underlying wave. This so-called parametric subharmonic instability (PSI) has been studied extensively for spatially and temporally monochromatic waves. Here, an asymptotic analysis of PSI for time-harmonic plane waves with locally confined spatial profile is made, in an effort to understand how such wave beams differ, in regard to PSI, from monochromatic plane waves. The discussion centres upon a system of coupled evolution equations that govern the interaction of a small-amplitude wave beam with short-scale subharmonic wavepackets in a nearly inviscid uniformly stratified Boussinesq fluid. For beams with general localized profile, it is found that triad interactions are not strong enough to bring about instability in the limited time that subharmonic perturbations overlap with the beam. On the other hand, for quasi-monochromatic wave beams whose profile comprises a sinusoidal carrier modulated by a locally confined envelope, PSI is possible if the beam is wide enough. In this instance, a stability criterion is proposed which, under given flow conditions, provides the minimum number of carrier wavelengths a beam of small amplitude must comprise for instability to arise.
Finger millet bran supplementation alleviates obesity-induced oxidative stress, inflammation and gut microbial derangements in high-fat diet-fed mice
Authors: Murtaza Nida , Baboota Ritesh K. , Jagtap Sneha , Singh Dhirendra P. , Khare Pragyanshu , Sarma Siddhartha M. , Podili Koteswaraiah , Alagesan Subramanian , Chandra T. S. , Bhutani K. K. , Boparai Ravneet K. , Bishnoi Mahendra , Kondepudi Kanthi Kiran
Published: September 2014

Several epidemiological studies have shown that the consumption of finger millet (FM) alleviates diabetes-related complications. In the present study, the effect of finger millet whole grain (FM-WG) and bran (FM-BR) supplementation was evaluated in high-fat diet-fed LACA mice for 12 weeks. Mice were divided into four groups: control group fed a normal diet (10 % fat as energy); a group fed a high-fat diet; a group fed the same high-fat diet supplemented with FM-BR; a group fed the same high-fat diet supplemented with FM-WG. The inclusion of FM-BR at 10 % (w/w) in a high-fat diet had more beneficial effects than that of FM-WG. FM-BR supplementation prevented body weight gain, improved lipid profile and anti-inflammatory status, alleviated oxidative stress, regulated the expression levels of several obesity-related genes, increased the abundance of beneficial gut bacteria (Lactobacillus, Bifidobacteria and Roseburia) and suppressed the abundance of Enterobacter in caecal contents (P≤ 0·05). In conclusion, FM-BR supplementation could be an effective strategy for preventing high-fat diet-induced changes and developing FM-BR-enriched functional foods.
Endolymphatic hydrops and Ménière's disease: a lesion meta-analysis
Authors: Pender D J
Published: September 2014

Objective:

To determine whether the distribution of membrane lesions associated with Ménière's disease is random, as might be expected from a pervasive process such as hydrops, or orderly, as might be expected if membrane resistance is graded.

Method:

A meta-analysis of temporal bone reports on 184 specimens demonstrating endolymphatic hydrops was undertaken to determine membrane lesion evolution and distribution.

Results:

Lesion distribution was found to be orderly and cochleocentric. No random scattershot lesions were reported in any study. Disease always started in the cochlear apex, even in non-symptomatic cases, and then involved the saccule, utricle, ampullae and canal system in that precise sequence as the disease progressed.

Conclusion:

The orderly lesion progression in the otopathology associated with Ménière's disease suggests that the hydropic process has a graded non-random effect on the labyrinth. These findings suggest a pathological staging system that may be useful in temporal bone evaluation.
Attentional bias to food-related visual cues: is there a role in obesity?
Authors: Doolan K. J. , Breslin G. , Hanna D. , Gallagher A. M.
Published: September 2014

The incentive sensitisation model of obesity suggests that modification of the dopaminergic associated reward systems in the brain may result in increased awareness of food-related visual cues present in the current food environment. Having a heightened awareness of these visual food cues may impact on food choices and eating behaviours with those being most aware of or demonstrating greater attention to food-related stimuli potentially being at greater risk of overeating and subsequent weight gain. To date, research related to attentional responses to visual food cues has been both limited and conflicting. Such inconsistent findings may in part be explained by the use of different methodological approaches to measure attentional bias and the impact of other factors such as hunger levels, energy density of visual food cues and individual eating style traits that may influence visual attention to food-related cues outside of weight status alone. This review examines the various methodologies employed to measure attentional bias with a particular focus on the role that attentional processing of food-related visual cues may have in obesity. Based on the findings of this review, it appears that it may be too early to clarify the role visual attention to food-related cues may have in obesity. Results however highlight the importance of considering the most appropriate methodology to use when measuring attentional bias and the characteristics of the study populations targeted while interpreting results to date and in designing future studies.
Assessment and Management of Suicide Risk in Primary Care
Authors: Saini Pooja , While David , Chantler Khatidja , Windfuhr Kirsten , Kapur Navneet
Published: September 2014

Background: Risk assessment and management of suicidal patients is emphasized as a key component of care in specialist mental health services, but these issues are relatively unexplored in primary care services. Aims: To examine risk assessment and management in primary and secondary care in a clinical sample of individuals who were in contact with mental health services and died by suicide. Method: Data collection from clinical proformas, case records, and semistructured face-to-face interviews with general practitioners. Results: Primary and secondary care data were available for 198 of the 336 cases (59%). The overall agreement in the rating of risk between services was poor (overall κ = .127, p = .10). Depression, care setting (after discharge), suicidal ideation at last contact, and a history of self-harm were associated with a rating of higher risk. Suicide prevention policies were available in 25% of primary care practices, and 33% of staff received training in suicide risk assessments. Conclusion: Risk is difficult to predict, but the variation in risk assessment between professional groups may reflect poor communication. Further research is required to understand this. There appears to be a relative lack of suicide risk assessment training in primary care.
Additional modes in a waveguide system of zero-index-metamaterials with defects
Authors: Fu Yangyang , Xu Yadong , Chen Huanyang
Published: September 2014

Zero-index-metamaterials (ZIM) have drawn much attention due to their intriguing properties and novel applications. Particularly, in a parallel plated ZIM waveguide system with defects, total reflection or transmission of wave can be achieved by adjusting the properties of defects. This effect has been explored extensively in different types of ZIM (e.g., epsilon-near-zero metamaterials, matched impedance ZIM, or anisotropic ZIM). Almost all previous literatures showed that only monopole modes are excited inside the defects if they are in circular cylinder shapes. However, the underlying physics for excited modes inside defects is wrongly ignored. In this work, we uncover that additional modes could be excited by theoretical analysis, which is important as it will correct the current common perception. For the case of matched impedance zero-index metamaterials (MIZIM), the additional dipole modes can be excited inside the defects when total transmission occurs. Moreover, we also observe the same results in Dirac-cone-like photonic crystals which have been demonstrated theoretically and experimentally to function as MIZIM. For another case of epsilon-near-zero metamaterials (ENZ), we find that additional higher order modes (e.g., tri-pole) can be excited inside the defects when total transmission happens. Numerical simulations are performed to verify our finding regarding the additional modes.
Double Charge Ordering States and Spin Ordering State Observed in a RFe2O4 System
Authors: Sun Fei , Wang Rui , Aku-Leh C. , Yang H. X. , He Rui , Zhao Jimin
Published: September 2014

Charge, spin and lattice degrees of orderings are of great interest in the layered quantum material RFe2O4 (R = Y, Er, Yb, Tm and Lu) system. Recently many unique properties have been found using various experimental methods. However so far the nature of the two-dimensional (2D) charge ordering (CO) state is not clear and no observation of its fine structure in energy has been reported. Here we report unambiguous observation of double 2D CO states at relatively high temperature in a polycrystalline Er0.1Yb0.9Fe2O4 using Raman scattering. The energy gaps between the 3D and the double 2D states are 170 meV (41.2 THz) and 193 meV (46.6 THz), respectively. We also observed a spin ordering (SO) state at below 210 K with characteristic energy of 45 meV (10.7 THz). Our investigation experimentally identified new fine structures of quantum orders in the system, which also extends the capability of optical methods in investigating other layered quantum materials.
Proline-induced enantioselective heterogeneous catalytic hydrogenation of isophorone on basic polymer-supported Pd catalysts
Authors: Schäfer Christian , Mhadgut Shilpa C. , Kugyela Nándor , Török Marianna , Török Béla
Published: September 2014

Formation of excess (R)-dihydroisophorone was observed (50% ee) at the early stage of the reaction supporting the existence of asymmetric catalysis.
Multifunctional mesoporous silica-supported palladium nanoparticles for selective phenol hydrogenation in the aqueous phase
Authors: Zhang Fengwei , Yang Hengquan
Published: September 2014

A simple, highly efficient and recoverable multifunctional core–shell structured mesoporous silica catalyst has been developed for selective phenol hydrogenation.
Epoxidation of cyclic enones with hydrogen peroxide catalysed by alkylcarboxylate-intercalated Ni–Zn mixed basic salts
Authors: Hara Takayoshi , Kurihara Jun , Ichikuni Nobuyuki , Shimazu Shogo
Published: September 2014

The interlayer spacing of layered Ni–Zn mixed basic salts (NiZn) can be precisely controlled by the intercalation of various long alkyl chain carboxylate anions into the NiZn interlayer.
Adsorption and stability of chiral modifiers based on 1-(1-naphthyl)-ethylamine for Pt catalysed heterogeneous asymmetric hydrogenations
Authors: Meemken Fabian , Steiger Titian , Holland Mareike C. , Gilmour Ryan , Hungerbühler Konrad , Baiker Alfons
Published: September 2014

Catalytic and in situ ATR-IR spectroscopic investigations provide mechanistic insight relevant to heterogeneous asymmetric hydrogenation on Pt catalyst using naphthylethylamine-based modifiers.
Structural limitations for optimizing garnet-type solid electrolytes: a perspective
Authors: Zeier Wolfgang G.
Published: September 2014

Structural limitations in the family of lithium conducting garnets lead to optimum structural parameters and a maximum attainable conductivity.
Structural and magnetic variations in tetranuclear NiII clusters: the effect of the reaction solvent and ligand substitution on product identity
Authors: Perlepe Panagiota S. , Athanasopoulou Angeliki A. , Alexopoulou Konstantina I. , Raptopoulou Catherine P. , Psycharis Vassilis , Escuer Albert , Perlepes Spyros P. , Stamatatos Theocharis C.
Published: September 2014

Changes of the solvent and organic ligand substituents in a general reaction system have led to three NiII4 clusters with different topologies and magnetic responses.
Controlled synthesis and characterization of the elusive thiolated Ag55cluster
Authors: Chakraborty Indranath , Mahata Shrabani , Mitra Anuradha , De Goutam , Pradeep Thalappil
Published: September 2014

A stable, Ag55cluster protected with 4-(tert-butyl)benzyl mercaptan (BBSH) was synthesized through a solid state route.