bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution and Local Species Diversity of Freshwater Ostracoda in Relation to Habitat in the Kahramanmaraş Province of Turkey
Authors: Külköylüoğlu Okan , Yavuzatmaca Mehmet , Akdemir Derya , Sari Necmettin
Published: July 2012

To understand the relationship between local (alpha) diversity of ostracods and their distribution, 95 different locations were randomly sampled from southern Kahramanmaraş (Turkey) between 7 June and 31 July, 2010. Total of 46 ostracods were encountered from 68 sites. Four alpha diversity indices (Shannon‐Wiener, Menhinick, Brillouin, Margalef) individually quantified higher species diversity and evenness for three types of habitats (limnocrene springs, ponds, stream). Diversity partitioning analyses revealed a significant and substantial beta‐diversity among the sites. First axis of CCA exhibited about 71% of the correlations between species and environmental variables. Water temperature, having either a negative or positive correlation with individual species, was the most influential factor affecting diversity. Altitude did not significantly affect the numbers of species identified from the elevation ranges of 400–600 m and 800–1000 m. At least nine cosmopolitan species from 56 sites had an important contribution to local diversity. Hence, suitability of aquatic (ecological) conditions and habitat types provide better explanations for ostracod diversity than do other abiotic factors such as altitude, pH and salinity. The results may support the Habitat Diversity Hypothesis but the study needs to be expanded to different regions and cannot be generalized at the moment. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Composition and Distribution of Recent Marine Ostracod Assemblages in the Bottom Sediments of Central Aegean Sea (SE Andros Island, Greece)
Authors: Tsourou Theodora
Published: July 2012

The present study provides a thorough analysis of the composition of recent marine ostracod populations from the bottom sediments of the central Aegean Sea, as well as their distribution patterns. In particular, a detailed qualitative and quantitative study of living ostracod assemblages was carried out in the marine environments of SE Andros Island. Sampling took place at Kastro and Korthi Gulf, both located at the southeastern coast of the Andros Island and from depth of 1.5 to 18 m, while additional samples were collected outside the gulfs at a depth of 120–180 m. Only ostracods considered to have been living at the time of collection were picked from the samples. A total of 51 species belonging to 34 genera were identified and four main ostracod assemblages, representing different biotopes, were distinguished. The results produced from the application of Q‐mode cluster analysis in the data set, the calculated assemblage structure indices for each sample, as well as the bathymetric and granulometric data are as follows: Hiltermannicythere rubra assemblage (occurs in substrates of sandy mud and at a water depth ranging from 40–60 m to the depth of 100 m or even more), Loxoconcha affinis, Xestoleberis sexmaculata assemblage (occurs in substrates of muddy very fine to fine sands and shallower environments), Semicytherura incogruens assemblage (occurs in very fine sands at a water depth from 10 to 28 m), Loculicytheretta pavonia and Neocytherideis fasciata, Pontocythere turbita assemblages (occurs mainly in fine sands and at a water depth between 3.5 and 15 m) and Urocythereis neapolitana assemblage (occurs in substrates of medium to coarse sand and at a water depth of less than 20 m). (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transition state theory thermal rate constants and RRKM‐based branching ratios for the N(2D) + CH4 reaction based on multi‐sState and multi‐reference Ab Initio calculations of interest for the titan's chemistry
Authors: Ouk Chanda‐Malis , Zvereva‐Loëte Natalia , Scribano Yohann , Bussery‐Honvault Béatrice
Published: July 2012

Multireference single and double configuration interaction (MRCI) calculations including Davidson (+Q) or Pople (+P) corrections have been conducted in this work for the reactants, products, and extrema of the doublet ground state potential energy surface involved in the N(2D) + CH4 reaction. Such highly correlated ab initio calculations are then compared with previous PMP4, CCSD(T), W1, and DFT/B3LYP studies. Large relative differences are observed in particular for the transition state in the entrance channel resolving the disagreement between previous ab initio calculations. We confirm the existence of a small but positive potential barrier (3.86 ± 0.84 kJ mol−1 (MR‐AQCC) and 3.89 kJ mol−1 (MRCI+P)) in the entrance channel of the title reaction. The correlation is seen to change significantly the energetic position of the two minima and five saddle points of this system together with the dissociation channels but not their relative order. The influence of the electronic correlation into the energetic of the system is clearly demonstrated by the thermal rate constant evaluation and it temperature dependance by means of the transition state theory. Indeed, only MRCI values are able to reproduce the experimental rate constant of the title reaction and its behavior with temperature. Similarly, product branching ratios, evaluated by means of unimolecular RRKM theory, confirm the NH production of Umemoto et al., whereas previous works based on less accurate ab initio calculations failed. We confirm the previous findings that the N(2D) + CH4 reaction proceeds via an insertion–dissociation mechanism and that the dominant product channels are CH2NH + H and CH3 + NH. © 2012 Wiley Periodicals, Inc.
Quantitative mapping of total choline in healthy human breast using proton echo planar spectroscopic imaging (PEPSI) at 3 Tesla
Authors: Zhao Chenguang , Bolan Patrick J. , Royce Melanie , Lakkadi Navneeth , Eberhardt Steven , Sillerud Laurel , Lee Sang‐Joon , Posse Stefan
Published: July 2012

Purpose:

To quantitatively measure tCho levels in healthy breasts using Proton‐Echo‐Planar‐Spectroscopic‐Imaging (PEPSI).

Materials and Methods:

The two‐dimensional mapping of tCho at 3 Tesla across an entire breast slice using PEPSI and a hybrid spectral quantification method based on LCModel fitting and integration of tCho using the fitted spectrum were developed. This method was validated in 19 healthy females and compared with single voxel spectroscopy (SVS) and with PRESS prelocalized conventional Magnetic Resonance Spectroscopic Imaging (MRSI) using identical voxel size (8 cc) and similar scan times (∼7 min).

Results:

A tCho peak with a signal to noise ratio larger than 2 was detected in 10 subjects using both PEPSI and SVS. The average tCho concentration in these subjects was 0.45 ± 0.2 mmol/kg using PEPSI and 0.48 ± 0.3 mmol/kg using SVS. Comparable results were obtained in two subjects using conventional MRSI. High lipid content in the spectra of nine tCho negative subjects was associated with spectral line broadening of more than 26 Hz, which made tCho detection impossible. Conventional MRSI with PRESS prelocalization in glandular tissue in two of these subjects yielded tCho concentrations comparable to PEPSI.

Conclusion:

The detection sensitivity of PEPSI is comparable to SVS and conventional PRESS‐MRSI. PEPSI can be potentially used in the evaluation of tCho in breast cancer. A tCho threshold concentration value of ∼0.7 mmol/kg might be used to differentiate between cancerous and healthy (or benign) breast tissues based on this work and previous studies. J. Magn. Reson. Imaging 2012;36:1113–1123. © 2012 Wiley Periodicals, Inc.
Measuring bone mineral density with fat–water MRI: comparison with computed tomography
Authors: Ho Kai‐Yu , Hu Houchun H. , Keyak Joyce H. , Colletti Patrick M. , Powers Christopher M.
Published: July 2012

Purpose:

To develop a method for measuring bone mineral density (BMD) with MRI, and to validate this method against quantitative computed tomography (QCT).

Materials and Methods:

A mathematical relationship between signal intensities from proton‐density‐weighted in‐phase images generated by multi‐fat‐peak T‐IDEAL MRI and BMD was derived using a set of calibration standards constructed from various concentrations of hydroxyapatite in water. Using these standards, the relationship between hydroxyapatite concentration and MRI signal intensity was examined. A T‐IDEAL protocol was performed on the patella of 5 volunteers and the signal model was used to compute BMD of all voxels of the patella. The BMD data were validated by obtaining QCT scans of the same patella, computing QCT BMD of all voxels, and comparing the MRI and QCT BMD data by performing linear regression analysis on a voxel‐by‐voxel basis.

Results:

A strong linear correlation between hydroxyapatite concentration of the calibration standards and MRI signal intensities was observed (r = 0.98; P < 0.01). In the patella, BMD measurements (N = 28796 voxels) from the MRI signal model were significantly correlated with those from QCT (r = 0.82; P < 0.001; slope = 1.02; and intercept = −0.26).

Conclusion:

A standardized phantom consisting of hydroxyapatite and water can be used to accurately quantify BMD in vivo using MRI. J. Magn. Reson. Imaging 2013;37:237–242. © 2012 Wiley Periodicals, Inc.
Combined hepatocellular carcinoma‐cholangiocarcinoma: Report of MR appearance in eleven patients
Authors: de Campos Rafael O.P. , Semelka Richard C. , Azevedo Rafael M. , Ramalho Miguel , Heredia Vasco , Armao Diane M. , Woosley John T.
Published: July 2012

Purpose:

To describe the magnetic resonance imaging (MRI) appearance of hepatic combined hepatocellular‐cholangiocarcinoma (cHCC‐CC) in 11 patients.

Materials and Methods:

The database of the Department of Pathology was cross‐referenced with the MRI database to identify patients with confirmed cHCC‐CC who had undergone MRI. Eleven consecutive patients were included (seven female, mean age 57.6 years). All patients were Caucasian. Five of 11 had a clinical history of chronic liver disease. Two radiologists retrospectively analyzed the images in consensus.

Results:

cHCC‐CC was a single mass in 10/11 patients. Margins were well‐defined in 6/11. All tumors showed heterogeneous hyperintensity on T2. On postcontrast imaging, 6/11 showed early ring‐enhancement (four noncirrhotic), with progressive enhancement in central portions, and 5/11 patients showed a diffuse heterogeneous early enhancement. Three of these five were cirrhotic and displayed partial washout with portions of contrast retention on later phases. Other findings included: late capsule enhancement (two patients), biliary dilatation (one), venous invasion (three), lymphadenopathy (six), and findings of cirrhosis (five).

Conclusion:

cHCC‐CC presents most commonly as a single mass. Five of 11 had MR findings of cirrhosis. Clues to the diagnosis were moderately high signal on T2, portions of tumor that show progressive enhancement/contrast retention, and frequent lack of capsule. Early enhancement patterns included early ring‐enhancement and diffuse heterogeneous enhancement. J. Magn. Reson. Imaging 2012;36:1139–1147. © 2012 Wiley Periodicals, Inc.
Semidiscrete Galerkin method for equations of motion arising in Kelvin‐Voigt model of viscoelastic fluid flow
Authors: Bajpai Saumya , Nataraj Neela , Pani Amiya K. , Damazio Pedro , Yuan Jin Yun
Published: July 2012

Finite element Galerkin method is applied to equations of motion arising in the Kelvin–Voigt model of viscoelastic fluids for spatial discretization. Some new a priori bounds which reflect the exponential decay property are obtained for the exact solution. For optimal L∞(L2) estimate in the velocity, a new auxiliary operator which is based on a modification of the Stokes operator is introduced and analyzed. Finally, optimal error bounds for the velocity in L∞(L2) as well as in L∞(H)‐norms and the pressure in L∞(L2)‐norm are derived which again preserves the exponential decay property. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
An approximation of incompressible miscible displacement in porous media by mixed finite elements and symmetric finite volume element method of characteristics
Authors: Yin Zhe , Rui Hongxing , Xu Qiang
Published: July 2012

A nonlinear system of two coupled partial differential equations models miscible displacement of one incompressible fluid by another in a porous medium. A sequential implicit time‐stepping procedure is defined, in which the pressure and Darcy velocity of the mixture are approximated by a mixed finite element method and the concentration is approximated by a combination of a modified symmetric finite volume element method and the method of characteristics. Optimal order convergence in H1 and in L2 are proved for full discrete schemes. Finally, some numerical experiments are presented. © 2012 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
control synthesis of switched discrete‐time fuzzy systems via hybrid approach
Authors: Xiang Weiming , Xiao Jian
Published: July 2012

Because switched system with nonlinear subsystems shows great difficulties in controller design by conventional methodologies, the fuzzy logic theory, which has been proven to be a practical and effective way to deal with the analysis and synthesis problems for complex nonlinear systems, is applied to design a class of hybrid fuzzy controller for switched discrete‐time fuzzy system in this paper. On a basis of one step prediction of switching signal, a hybrid parallel distributed compensation (PDC) control strategy is proposed, which includes two necessary parts: the state feedback controllers for subsystems and the update feedback controllers for switching instants. In both arbitrary and dwell‐time switching cases investigated, it is proved that the hybrid PDC controller contains less conservativeness than conventional switched PDC controller. Numerical examples are given to illustrate the effectiveness and advantages of the proposed approach. Copyright © 2012 John Wiley & Sons, Ltd.
Polymer electrolyte membranes composed of an electrospun poly(vinylidene fluoride) fibrous mat in a poly(4‐vinylpyridine) matrix
Authors: Nah Changwoon , Jeong Kwang‐Un , Lee Youn‐Sik , Lee Soo‐Hyoung , Kader Mohamed Mustafa Abdul , Lee Hong Ki , Ahn Jou‐Hyeon
Published: July 2012

Newly proposed polymer electrolyte membranes (PEMs) composed of an electrospun poly(vinylidene fluoride) (PVDF) fibrous mat embedded in a poly(4‐vinylpyridine) (P4VP) matrix were successfully fabricated in order to improve the mechanical and dimensional stabilities and ionic conductivity of membranes in lithium rechargeable batteries. Fourier transform infrared spectroscopic analysis showed that as a result of the use of a high voltage during electrospinning the crystalline structure of PVDF changed partially from α‐phase to β‐phase. Energy‐dispersive X‐ray spectroscopy confirmed the existence of crosslinked P4VP in the PVDF fibrous mat. The electrolyte uptakes of PVDF and PVDF/P4VP composite mats were higher than that of PVDF cast film. The tensile properties of PVDF/P4VP composite mat were considerably improved compared to those of the pristine PVDF fibrous mat under both dry and wet (soaked with electrolyte) conditions. In addition, the mechanical and dimensional stabilities of the PVDF/P4VP composite PEM were further enhanced due to crosslinking between the P4VP chains. Furthermore, the PVDF/P4VP composite PEM exhibited an ionic conductivity that was an order of magnitude higher than that of traditional PVDF film. © 2012 Society of Chemical Industry
Round‐robin measurement intercomparison of c‐Si PV modules among Asian testing laboratories
Authors: Hishikawa Yoshihiro , Liu Haitao , Hsieh Hsin‐Hsin , Inoue Takamitsu , Kim Kyung‐Soo , Limsakul Chamnan , Kim Seong‐Won , Ninae Ruengrit , Morita Kengo
Published: July 2012

Because of recent advances in the production and installation of photovoltaic (PV) systems, the international conformity of PV module performance measurement has become increasingly important. The increase in PV production sites is particularly significant in the Asian region. The present paper summarizes and discusses the results of a round‐robin intercomparison of crystalline silicon modules among national laboratories and certified testing laboratories in the Asian region conducted from 2009 to 2011. Most of the values of Pmax measured at the different laboratories were within a ±2% range, although some Pmax results showed differences of up to about 3%. This result is comparable to that obtained in the recent intercomparison among international laboratories. Possible sources of difference in the measured values of Isc, Voc, FF, and Pmax are discussed, for further improvement of international conformity in PV measurement technologies. Copyright © 2012 John Wiley & Sons, Ltd.
Rapid annealing of reactively sputtered precursors for Cu2ZnSnS4 solar cells
Authors: Scragg Jonathan J. , Ericson Tove , Fontané Xavier , Izquierdo‐Roca Victor , Pérez‐Rodríguez Alejandro , Kubart Tomas , Edoff Marika , Platzer‐Björkman Charlotte
Published: July 2012

Cu2ZnSnS4 (CZTS) is a promising thin‐film absorber material that presents some interesting challenges in fabrication when compared with Cu(In,Ga)Se2. We introduce a two‐step process for fabrication of CZTS films, involving reactive sputtering of a Cu‐Zn‐Sn‐S precursor followed by rapid annealing. X‐ray diffraction and Raman measurements of the sputtered precursor suggest that it is in a disordered, metastable CZTS phase, similar to the high‐temperature cubic modification reported for CZTS. A few minutes of annealing at 550 °C are sufficient to produce crystalline CZTS films with grain sizes in the micrometer range. The first reported device using this approach has an AM1.5 efficiency of 4.6%, with Jsc and Voc both appearing to be limited by interface recombination. Copyright © 2012 John Wiley & Sons, Ltd.
Recognition of aromatic amino acids and proteins withp‐sulfonatocalix[4]arene – A luminescence and theoretical approach
Authors: Muthu Mareeswaran Paulpandian , Prakash Muthuramalingam , Subramanian Venkatesan , Rajagopal Seenivasan
Published: July 2012

The host–guest interaction ofp‐sulfonatocalix[4]arene (p‐SC4) with aromatic amino acids (AAs) and two proteins has been studied using UV–Vis absorption, fluorescence, and theoretical methods. Spectral studies supported by binding constant and calculated binding energy (BE) values show thatp‐SC4 binds more strongly with tyrosine compared with other AAs. The application of Bader's theory of atoms in molecule shows the involvement of various types of noncovalent interactions in the formation of the host–guest complexes. Both tyrosine and histidine have strong electrostatic interaction with the sulfonato group and other two AAs have dominant π−π interaction with the aromatic rings of calixarene. In addition, the role of C−H···O, C−H···π and lone pair···π (lp···π) interactions in the stabilization ofp‐SC4‐AA complexes has also been realized from the atoms in molecule analysis. The electron density at the bond critical points varies with the calculated BEs and trend in BEs is in good agreement with the experimental binding constant values. The work has been extended to the binding ofp‐SC4 with proteins, bovine serum albumin and ovalbumin. Ovalbumin exhibits stronger binding withp‐SC4 than bovine serum albumin. Copyright © 2012 John Wiley & Sons, Ltd.
Genetic counseling does not fulfill the counselees' need for certainty in hereditary breast/ovarian cancer families: an explorative assessment
Authors: Vos Joël , Menko Fred H. , Oosterwijk Jan C. , van Asperen Christi J. , Stiggelbout Anne M. , Tibben Aad
Published: July 2012

Background

Many cancer‐patients undergo DNA testing in the BRCA1/2 genes to receive information about the likelihood that cancer is heritable. Previous nonsystematic studies suggested that DNA testing often does not fulfill the counselees' needs for certainty. We explored the balance between the counselees' need for certainty and perceived certainty (NfC‐PC, i.e., level of fulfillment of NfC) regarding the specific domains of DNA test result, heredity and cancer. We also examined relationships of NfC‐PC with coping styles and distress.

Method

Before disclosure of BRCA1/2 test results for hereditary breast/ovarian cancer (T1), questionnaires were filled in by 467 cancer‐patients. Another questionnaire (T2) was filled in after disclosure of pathogenic mutation results (n = 30), uninformative results (n = 202) or unclassified‐variants (n = 16).

Results

Before and after DNA test result disclosure, overall 58–94% of all counselees experienced unfulfilled NfC regarding the DNA test result, heredity and cancer. Compared with T1, the communication of pathogenic mutations (T2) caused more fulfillment of the NfC about the DNA test result, but less about cancer and heredity (p < .01). Compared with T1, unclassified variants (T2) did not significantly change the extent of fulfillment of all counselees' needs for certainty (NfC > PC). Compared with T1, uninformative results (T2) caused more fulfillments of all needs than before disclosure (p < 0.01). Counselees differentiated NfC and PC between the domains of DNA‐test result, heredity and cancer ( p < 0.01). The unfulfilled needs for certainty (NfC‐PC) were uncorrelated with cognitive understanding of the DNA test result.

Conclusion

The counselees' NfC needs more attention in research and practice, for example, when the potential uncertainties of testing are discussed. The counselees' NfC may be assessed and used in tailored, mutual communication of DNA test results. Copyright © 2012 John Wiley & Sons, Ltd.
Interleukin‐6 promoter variants, prostate cancer risk, and survival
Authors: Tindall Elizabeth A. , Severi Gianluca , Hoang Hoa N. , Southey Melissa C. , English Dallas R. , Hopper John L. , Giles Graham G. , Hayes Vanessa M. ,   Australian Prostate Cancer BioResource
Published: July 2012

BACKGROUND

Inflammation has been implicated in prostate cancer (PCa) pathogenesis. Promoter DNA variants responsible for differential expression of key cytokines may therefore influence susceptibility to PCa.

METHODS

Two interleukin‐6 (IL‐6) promoter variants, −174G>C and −6331T>C, were genotyped for association with PCa risk and survival using the Risk Factors for Prostate Cancer Study (RFPCS, 825 cases and 732 controls) and the Melbourne Collaborative Cohort Study (MCCS, 818 cases and 1,745 controls). Impact of genotypes on IL‐6 transcriptional activity was measured using Low Density Arrays.

RESULTS

A significant increase in IL‐6 transcriptional activity in malignant compared to benign prostate tissue supports a role for IL‐6 in PCa. The −174G>C variant showed no association with PCa risk, overall survival, or IL‐6 transcriptional activity. The −6331 C‐allele was significantly associated with an increased risk in the RFPCS (OR = 1.29, 95% CI = 1.08–1.54), but not in the MCCS. In the MCCS however, cases presenting with a CC genotype conferred a higher risk of mortality (HR = 2.27, 95% CI = 1.34–3.85), which was maintained although reduced overall in the pooled analysis with RFPCS (HR = 1.68, 95% CI = 1.10–2.54). Furthermore, we associate the minor C‐allele with a significant decrease in IL‐6 transcriptional activity.

CONCLUSIONS

While our study refutes a role for IL‐6 −174G>C, it is the first to implicate −6331T>C with PCa risk and poor survival. Our observation that −6331T>C has a significant impact on IL‐6 transcriptional activity, calls for further investigations into the role of this variant as a novel PCa biomarker. Prostate 72:1701–1707, 2012. © 2012 Wiley Periodicals, Inc.
Influence of microstructure on the cross‐plane oxygen ion conductivity of yttria stabilized zirconia thin films
Authors: Schlupp Meike V. F. , Scherrer Barbara , Ma Huan , Grolig Jan G. , Martynczuk Julia , Prestat Michel , Gauckler Ludwig J.
Published: July 2012

The electrical cross‐plane conductivity of 8 mol% yttria stabilized zirconia (YSZ) thin films prepared by different deposition techniques, namely aerosol assisted chemical vapor deposition, wet spray pyrolysis (SP), and pulsed laser deposition (PLD), is correlated with their microstructure. Depending on deposition technique and process conditions, microstructures ranging from amorphous to randomly oriented nanocrystalline or columnar with preferred (111) orientation are obtained. Cross‐plane AC impedance measurements of these thin films show that the oxygen ion conductivity of randomly oriented nanocrystalline samples is determined by the grain boundaries, which show significantly lower transport properties than the grain interior. In columnar microstructures, the conductivity is determined by ionic transport through the grains only. The same conduction behavior is found for amorphous and randomly oriented microstructures with grain sizes between 3 nm and 9 nm, indicating that no true size effects occur in 8 mol% YSZ.

magnified image

Grain and grain boundary conductivity determined for nanocrystalline 8 mol% yttria stabilized zirconia thin films of different microstructures.
Direct fabrication of microelectrodes on a polymer substrate using selective ultrashort pulsed laser ablation of inkjet‐printed Ag lines
Authors: Lee S. H. , Lee D. J. , Lee C. K. , Lee Y. H. , Wereley S. T. , Oh J. H.
Published: July 2012

An inkjet‐based ultrashort pulsed laser patterning on a polymer substrate is presented with high‐laser scanning speeds. The effects of the laser processing parameters on the ablation characteristics were studied to accomplish damage‐free laser ablation. Laser ablation characteristics depend on input energy, scanning speed, and number of scans. Final width of microelectrodes can be flexibly controlled by multiple selective ablations. Well‐defined, uniform microelectrodes without damaging their microstructure, and the underlying polymer substrate are demonstrated via a direct pattering process combining inkjet printing with ultrashort pulsed laser ablation. These microelectrodes exhibit little influence of thermal effect of laser ablation, resulting in little variation in their electrical performances.

magnified image
Reconstructing interference fringes in slit experiments by complex quantum trajectories
Authors: Yang Ciann‐Dong , Su Kuan‐Chang
Published: July 2012

There are external and internal representations for a quantum state Ψ. External representation is commonly adopted in the standard quantum mechanics by exploiting probability density function Ψ*Ψ to explain the observed interference fringes in slit experiments. On the other hand, in quantum Hamilton mechanics, the quantum state Ψ has a dynamical representation that reveals the internal mechanism underlying the externally observed interference fringes. The internal representation of Ψ is described by a set of Hamilton equations of motion, by which quantum trajectories of a particle moving in Ψ can be solved. In this article, millions of complex quantum trajectory connecting slits to a screen are solved from the Hamilton equations, and the statistical distribution of their arrivals on the screen is shown to reproduce the observed interference fringes. This appears to be the first quantitative verification of the equivalence between the trajectory‐based statistics and the wavefunction‐based statistics on slit experiments. © 2012 Wiley Periodicals, Inc.
Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry combined with multidimensional scaling, binary hierarchical cluster tree and selected diagnostic masses improves species identification of Neolithic keratin sequences from furs of the Tyrolean Iceman Oetzi
Authors: Hollemeyer Klaus , Altmeyer Wolfgang , Heinzle Elmar , Pitra Christian
Published: July 2012

The identification of fur origins from the 5300‐year‐old Tyrolean Iceman's accoutrement is not yet complete, although definite identification is essential for the socio‐cultural context of his epoch. Neither have all potential samples been identified so far, nor there has a consensus been reached on the species identified using the classical methods. Archaeological hair often lacks analyzable hair scale patterns in microscopic analyses and polymer chain reaction (PCR)‐based techniques are often inapplicable due to the lack of amplifiable ancient DNA. To overcome these drawbacks, a matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) method was used exclusively based on hair keratins. Thirteen fur specimens from his accoutrement were analyzed after tryptic digest of native hair. Peptide mass fingerprints (pmfs) from ancient samples and from reference species mostly occurring in the Alpine surroundings at his lifetime were compared to each other using multidimensional scaling and binary hierarchical cluster tree analysis. Both statistical methods highly reflect spectral similarities among pmfs as close zoological relationships. While multidimensional scaling was useful to discriminate specimens on the zoological order level, binary hierarchical cluster tree reached the family or subfamily level. Additionally, the presence and/or absence of order, family and/or species‐specific diagnostic masses in their pmfs allowed the identification of mammals mostly down to single species level. Red deer was found in his shoe vamp, goat in the leggings, cattle in his shoe sole and at his quiver's closing flap as well as sheep and chamois in his coat. Canid species, like grey wolf, domestic dog or European red fox, were discovered in his leggings for the first time, but could not be differentiated to species level. This is widening the spectrum of processed fur‐bearing species to at least one member of the Canidae family. His fur cap was allocated to a carnivore species, but differentiation between brown bear and a canid species could not be made with certainty. Copyright © 2012 John Wiley & Sons, Ltd.
In vivo metabolic investigation of moxifloxacin using liquid chromatography/electrospray ionization tandem mass spectrometry in combination with online hydrogen/deuterium exchange experiments
Authors: Raju B. , Ramesh M. , Borkar Roshan M. , Srinivas R. , Padiya Raju , Banerjee Sanjay K.
Published: July 2012

RATIONALE

Tuberculosis is a leading cause of death from an infectious disease and moxifloxacin is an effective drug as compared to other fluoroquinolones. To date only two metabolites of the drug are known. Therefore, the present study on characterization of hitherto unknown in vivo metabolites of moxifloxacin using liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS) is undertaken.

METHODS

In vivo metabolites of moxifloxacin have been identified and characterized by using LC/ESI‐MS/MS in combination with an online hydrogen/deuterium (H/D) exchange technique. To identify in vivo metabolites, blood, urine and faeces samples were collected after oral administration of moxifloxacin to Sprague–Dawley rats. The samples were prepared using an optimized sample preparation approach involving protein precipitation, liquid‐liquid extraction followed by solid‐phase extraction and LC/MS/MS analysis.

RESULTS

A total of nine phase I and ten phase II metabolites of moxifloxacin have been identified in urine samples including N‐sulphated, glucuronide and hydroxylated metabolites which are also observed in plasma samples. In faeces samples, only the N‐sulphated metabolite is observed. The structures of metabolites have been elucidated based on fragmentation patterns, accurate mass measurements and online H/D exchange LC/MS/MS experiments. Online H/D exchange experiments are used to support the identification and structural characterization of drug metabolites.

CONCLUSIONS

A total of 19 in vivo metabolites of moxifloxacin have been characterized using LC/ESI‐MS/MS in combination with accurate mass measurements and online H/D exchange experiments. The main phase I metabolites of moxifloxacin are hydroxylated, decarbonylated, desmethylated and desmethylhydroxylated metabolites which undergo subsequent phase II glucuronidation pathways. Copyright © 2012 John Wiley & Sons, Ltd.
Studies in search of selective detection of isomeric biogenic hexen‐1‐ols and hexanal by flowing afterglow tandem mass spectrometry using [H3O]+ and [NO]+ reagent ions
Authors: Dhooghe Frederik , Vansintjan Robbe , Schoon Niels , Amelynck Crist
Published: July 2012

RATIONALE

Plants emit a blend of oxygenated volatile C6 compounds, known as green leaf volatiles (GLVs), in response to leaf tissue damage related to stress conditions. On‐line chemical ionization mass spectrometry (CI‐MS) techniques have often been used to study the dynamics of these emissions but they fail to selectively detect some important GLV compounds.

METHODS

A flowing afterglow tandem mass spectrometer (FA‐TMS) was used to investigate the feasibility of selective on‐line detection of isomeric hexen‐1‐ols and hexanal. Product ions at m/z 101 and 83 from chemical ionization (CI) of these compounds by [H3O]+, and product ions at m/z 100, 99, 83, 82 and 72 from CI by [NO]+, have been subjected to collision‐induced dissociation (CID) in the collision cell of the TMS at center‐of‐mass energies ranging between 0 and 9 eV.

RESULTS

CID of product ions at m/z 101 and 83 from CI of GLVs with [H3O]+ and of product ions at m/z 83, 82 and 72 from CI of GLVs with [NO]+ resulted in identical fragmentation patterns for all measured compounds, ruling out any selectivity. However, CID of product ions at m/z 100 and 99 from CI by [NO]+ led to CID product ions with abundances differing largely between the compounds, allowing the fast selective detection of 2‐hexen‐1‐ols, 3‐hexen‐1‐ols and hexanal with a chosen accuracy within a well‐defined range of relative concentrations.

CONCLUSIONS

This research illustrates that, in contrast to common CI‐MS techniques, FA‐TMS allows the selective detection of hexanal in a mixture of hexanal and hexen‐1‐ols with a chosen accuracy for a well‐defined range of relative concentrations and represents a step forward in the search for selective detection of GLVs in CI‐TMS. Copyright © 2012 John Wiley & Sons, Ltd.
Backbone fragmentations of [M–H]– anions from peptides. Reinvestigation of the mechanism of the beta prime cleavage
Authors: Wang Tianfang , Tran T. T. Nha , Calabrese Antonio N. , Bowie John H.
Published: July 2012

RATIONALE

An experimental study has shown that the structure of a β' ion proposed earlier is incorrect. Backbone cleavage β' anions have structures R(NH–) from systems [[RNHCH(X)CONHCH(Y)CO2H (or C‐terminal CONH2) – H]– (where R is the rest of the peptide molecule and X and Y represent the α side chains of the individual amino acid residues).

METHODS

Ab initio calculations were carried out at the CAM‐B3LYP/6‐311++g(d,p) level of theory.

CONCLUSIONS

The calculations suggest that RNH– ions are formed by SNi cyclisation processes involving either (i) the C‐terminal CO2– or C‐terminal [CONH]– as appropriate, or (ii) an enolate ion [‐NHC–(Y)‐] cyclising at the backbone CH of the ‐CH(X)‐ group. Concomitant C–N bond cleavage then liberates an RNH– ion, processes which can occur along the peptide backbone. Copyright © 2012 John Wiley & Sons, Ltd.
Platinum vapor deposition surface‐assisted laser desorption/ionization for imaging mass spectrometry of small molecules
Authors: Kawasaki Hideya , Ozawa Tomoyuki , Hisatomi Hirotaka , Arakawa Ryuichi
Published: July 2012

RATIONALE

Matrix‐assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) allows for the simultaneous detection and imaging of several molecules in a sample. However, when using an organic matrix in the MALDI‐IMS of small molecules, inhomogeneous matrix crystallization may yield poorly reproducible peaks in the mass spectra. We describe a solvent‐free approach that employs a homogeneously deposited metal nanoparticle layer (or film) for small‐molecule detection.

METHODS

Platinum vapor deposition surface‐assisted laser desorption/ionization imaging mass spectrometry (Pt vapor deposition SALDI‐IMS) of small molecules was performed as a solvent‐free and organic‐matrix‐free method. A commercially available magnetron sputtering device was used for Pt deposition. Vapor deposition of Pt produced a homogenous layer of nanoparticles over the surface of the target imaging sample.

RESULTS

The effectiveness of Pt vapor deposition SALDI‐IMS was demonstrated for the direct detection of small analytes of inkjet ink on printed paper as well as for various other analytes (saccharides, pigments, and drugs) separated by thin‐layer chromatography (TLC), without the need for extraction or concentration processes. The advantage of choosing Pt instead of Au in SALDI‐IMS was also shown.

CONCLUSIONS

A solvent‐free approach involving the direct deposition of Pt on samples (SALDI‐IMS) is effective for the analysis of inkjet‐printed papers and various analytes separated by TLC. This method would be useful in imaging analyses of various insulating materials such as polymers and biological materials. Copyright © 2012 John Wiley & Sons, Ltd.
Rapid differentiation of nucleotide phosphoramidate diastereomers by electrospray ionization tandem mass spectrometry
Authors: Bao Donghui , Reddy P. Ganapati , Ross Bruce S. , Sofia Michael J.
Published: July 2012

RATIONALE

Nucleotide phosphoramidates are prodrugs which effectively deliver the active nucleotide to target tissues. It was shown that the individual phosphoramidate diastereomers have different antiviral activity, although the active nucleotide is the same. Therefore, a fast and simple analytical method is needed to characterize the individual diastereomeric phosphoramidate prodrugs.

METHODS

Stock solutions of diastereomeric nucleotide phosphoramidate prodrugs, i.e., 5′‐phosphate derivatives of the β‐D‐2′‐deoxy‐2′‐α‐fluoro‐2′‐β‐C‐methyluridine nucleotide, were made in 25% acetonitrile to achieve a final concentration of 10 µg/mL. The samples were studied using high‐performance liquid chromatography (HPLC) coupled with electrospray ionization tandem mass spectrometry (ESI‐MS/MS).

RESULTS

The MS/MS spectra of diastereomeric pairs showed substantial differences in the relative abundances of a characteristic ion in negative mode, which is proposed to be a cyclic phosphoramidate ion. Results were confirmed by the MS/MS spectrum of an analog without the NH proton and deuterium exchange experiment. Furthermore, the diastereomer‐specific fragmentation behavior in negative ESI‐MS was used to characterize a series of nucleotide phosphoramidates with different amino acid and aromatic substituents.

CONCLUSIONS

An HPLC/MS/MS method was developed for the differentiation of the diastereomers of phosphoramidate prodrugs. In negative mode MS/MS spectra, the cyclic phosphoramidate ions yielded unambiguous distinction. This method presented a rapid and simple way for the characterization of nucleotide phosphoramidates. Copyright © 2012 John Wiley & Sons, Ltd.
Electrophoretic Build‐Up of Alternately Multilayered Films and Micropatterns Based on Graphene Sheets and Nanoparticles and their Applications in Flexible Supercapacitors
Authors: Niu Zhiqiang , Du Jianjun , Cao Xuebo , Sun Yinghui , Zhou Weiya , Hng Huey Hoon , Ma Jan , Chen Xiaodong , Xie Sishen
Published: July 2012

Graphene nanosheets and metal nanoparticles (NPs) have been used as nano‐building‐blocks for assembly into macroscale hybrid structures with promising performance in electrical devices. However, in most graphene and metal NP hybrid structures, the graphene sheets and metal NPs (e.g., AuNPs) do not enable control of the reaction process, orientation of building blocks, and organization at the nanoscale. Here, an electrophoretic layer‐by‐layer assembly for constructing multilayered reduced graphene oxide (RGO)/AuNP films and lateral micropatterns is presented. This assembly method allows easy control of the nano‐architecture of building blocks along the normal direction of the film, including the number and thickness of RGO and AuNP layers, in addition to control of the lateral orientation of the resultant multilayered structures. Conductivity of multilayered RGO/AuNP hybrid nano‐architecture shows great improvement caused by a bridging effect of the AuNPs along the out‐of‐plane direction between the upper and lower RGO layers. The results clearly show the potential of electrophoretic build‐up in the fabrication of graphene‐based alternately multilayered films and patterns. Finally, flexible supercapacitors based on multilayered RGO/AuNP hybrid films are fabricated, and excellent performance, such as high energy and power densities, are achieved.
Concise Review: Chromatin and Genome Organization in Reprogramming
Authors: Biran Alva , Meshorer Eran
Published: July 2012

The ability to reprogram somatic cells to pluripotency is continuingly attracting increasing amounts of attention, providing both potential opportunities for regenerative medicine, as well as an intriguing model to study basic mechanisms of developmental reversal and epigenetic erasure. Currently, nuclear reprogramming is an inefficient process and a better understanding of its components and the underlying mechanisms will no doubt enable us to increase its robustness and to gain a deeper understanding of its regulation. Here we focus on the reprogramming process from the chromatin and genome organization perspective, describing the chromatin changes that occur both globally and locally. At the global level, chromatin decondenses toward the characteristic ‘open’ state, while locally, chromatin reorganization supports the silencing of lineage-specific genes and the activation of pluripotency-related genes. Importantly, the proteins that regulate this process are being identified, revealing different layers of chromatin regulation, including histone modifications, histone variants, chromatin remodeling and genomic DNA methylation. The emerging theme is that chromatin and genome organization are not only altered during the transition from a somatic to a pluripotent state, but also play active, regulatory roles during the reprogramming process.
Lysophosphatidic Acid Induces Migration of Human Lung-Resident Mesenchymal Stem Cells Through the β-Catenin Pathway
Authors: Badri Linda , Lama Vibha N.
Published: July 2012

Mesenchymal stem cells (MSCs) have been demonstrated to reside in human adult organs. However, mechanisms of migration of these endogenous MSCs within their tissue of origin are not well understood. Here, we investigate migration of human adult lung-resident (LR) mesenchymal progenitor cells. We demonstrate that bioactive lipid lysophosphatidic acid (LPA) plays a principal role in the migration of human LR-MSCs through a signaling pathway involving LPA1-induced β-catenin activation. LR-MSCs isolated from human lung allografts and lungs of patients with scleroderma demonstrated a robust migratory response to LPA in vitro. Furthermore, LPA levels correlated with LR-MSC numbers in bronchoalveolar lavage (BAL), providing demonstration of the in vivo activity of LPA in human adult lungs. Migration of LR-MSCs was mediated via LPA1 receptor ligation and LPA1 silencing significantly abrogated the migratory response of LR-MSCs to LPA as well as human BAL. LPA treatment of LR-MSCs induced protein kinase C-mediated glycogen synthase kinase-3β phosphorylation, with resulting cytoplasmic accumulation and nuclear translocation of β-catenin. TCF/LEF dual luciferase gene reporter assay demonstrated a significant increase in transcriptional activity after LPA treatment. LR-MSC migration and increase in reporter gene activity in the presence of LPA were abolished by transfection with β-catenin small interfering RNA demonstrating that β-catenin is critical in mediating LPA-induced LR-MSC migration. These data delineate a novel signaling pathway through which ligation of a G protein-coupled receptor by a biologically relevant lipid mediator induces migration of human tissue-resident mesenchymal progenitors.
Task transmission control with dynamic lightpath setup for constant processing delay in an optical grid
Authors: Nakamura Yukinori , Tachibana Takuji , Matsui Genki
Published: July 2012

This paper proposes a task transmission control with dynamic lightpath setup in an optical grid. In our proposed method, a job manager changes the number of tasks in a resource manager dynamically so as to maintain a constant processing delay. It leads to effective utilization of computing resource. I‐PD control is applied to maintain efficient network management. Furthermore, in order to avoid frequent lightpath setup process, multiple lightpaths are established simultaneously by our proposed algorithm. Numerical results show the effectiveness of the proposed task transmission method. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Tell Me About Fred's Fat Foot Again: Four Tips for SuccessfulPALessons
Authors: Murray Bruce A.
Published: July 2012

This teaching tip applies research on phoneme awareness (PA) to propose an instructional model for teachingPA. Research suggests children need to learn the identifying features of phonemes to recognize them in spoken words. In the model, teachers focus on one phoneme at a time; make it memorable to children through sound analogies supported by illustrations, hand gestures, and graphemes; provide engaging practice detecting the phoneme in “tongue ticklers” and in spoken words; and lead children to transfer their knowledge of phonemes to the task of learning to read words.
Determination of enthalpies (‘Heats’) of formation
Authors: Rogers Donald W. , Zavitsas Andreas A. , Matsunaga Nikita
Published: July 2012

Determination of enthalpies of formation, now well into its second century, continues to be an active research field. Classical combustion thermochemistry, known by Lavoisier, is carried out with precision in several laboratories, though usually on the microscale, as appropriate to the small quantities of rare or unstable species preparative chemists are able to win and purify. Nonclassical methods such as differential scanning calorimetry and proton emission techniques are practiced. Enthalpy estimation based on additivity has been brought to an improved level of accuracy, and its basis in molecular structure has been examined with the goal of achieving maximum simplicity. Discrepancies between experimental results and additive estimates due to ‘special effects’ have brought about a considerable amount of causative speculation in the literature. Quantum mechanical methods have enjoyed increased proliferation through new methods of finding enthalpies of formation and other thermochemical and molecular properties such as heat capacity and entropy. Powerful basis set and configuration interaction software is available within the Gaussian© suites of programs. New levels of accuracy, in the kilojoules per mole range, have been achieved by Wn methods, and wider generality is enjoyed by methods based on density functional theory. New tabulation methods have been introduced that use computer error estimation procedures to root out flawed experimental results and increase overall reliability of the data one selects from the compilation.

This article is categorized under:

Structure and Mechanism > Molecular Structures
A Copper‐Carboxylate Layer‐Framework with Pseudo‐­Kagomé Net
Authors: Wang Xiao‐Feng , Zhang Xiu‐Lian , Zhou Xin , Li Jun , Kuang Yun‐Fei , Chen Ji‐Hao
Published: July 2012

A two dimensional coordination polymer with pseudo‐Kagomé net [Cu3(btc)2(NH3)8(H2O)] was prepared from Cu(NO3)2·3H2O and 1, 3, 5‐benzenetricarboxylic acid (btc) in ammonia aqua solution and was structurally characterized by X‐ray diffraction. The magnetic susceptibility measurements, measured from 2 to 300 K, revealed a weak anti‐ferromagnetic interaction between the CuII ions via the btc ligands.