bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inactivation of the Gastrokine 1 gene in gastric adenomas and carcinomas
Authors: Yoon Jung Hwan , Song Jae Hwi , Zhang Cao , Jin Meishan , Kang Young Hwi , Nam Suk Woo , Lee Jung Young , Park Won Sang 
Published: December 2010

AbstractGastrokine 1 (GKN1) plays a role in the gastric mucosal defence mechanism and may be a gastric tumour suppressor. We have investigated whether inactivation of the GKN1 gene is involved in the development and/or progression of gastric cancers. GKN1 protein expression was examined in gastric adenomas and cancer and we also analysed GKN1 mutation and epigenetic alteration, DNA copy number change and mRNA transcript expression. The effect of GKN1 on cell proliferation and death was examined in wild‐type GKN1‐transfected AGS gastric cancer cells. Reduced or loss of GKN1 expression was detected in 36 (90%) and 170 (89.5%) of 40 adenomas and 190 gastric cancers, respectively. Statistically, there was no significant relationship between altered expression of GKN1 protein and clinicopathological parameters, including depth of invasion, location and lymph node metastasis (χ2 test, p > 0.05). In western blot analysis, absence or reduced expression was found in 21 (84.0%) of 25 gastric carcinomas. No mutation was detected in gastric tumours, and hypermethylation of GKN1 gene was found in two tumours. DNA copy number and mRNA transcript of GKN1 were significantly decreased in gastric cancers. In functional analysis, AGS gastric cancer cells transfected with GKN1 wild‐type showed marked inhibition of cell proliferation and induction of cell death. These data suggest that inactivation of the GKN1 gene may play an important role in the development of sporadic gastric cancers, as an early event. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Self‐reported prevalence of hypersensitivity reactions against drugs among medical students: does awareness cause any difference?
Authors: Bavbek Sevim , Erkekol Ferda Öner , Çelik Gülfem Elif , Gönüllü İpek , Mısırlıgil Zeynep 
Published: December 2010

AbstractPurposeTrue epidemiologic data on hypersensitivity reactions to drugs are scarce. More accurate data may be obtained in more specific clinical settings. Considering their educational background, medical students may be an appropriate target audience for evaluating prevalence of drug hypersensitivity. This study is designed to determine the prevalence of self‐reported drug hypersensitivity alongside related factors among young adults.MethodsA structured questionnaire was administered to the students.ResultsA total of 1267 students (mean age: 21.71 + 1.90 years, F/M: 648/619) from all grades responded to the survey. The mean prevalence of self‐reported drug hypersensitivity was 4.7% (60/1267). The most frequently involved drugs were beta‐lactam antibiotics (55%) followed by non‐steroidal anti‐inflammatory drugs (28%). The most commonly reported clinical presentations were cutaneous (43.3%), followed by systemic (36.8%), cardiovascular (8.3%) and respiratory (8.3%) symptoms. Factors related with reported reactions were higher grades (p = 0.015, OR: 2.09), female gender (p = 0.006, OR: 2.13), personal history of allergic diseases (p = 0.001, OR: 2.64), and family history of drug hypersensitivity (p < 0.001, OR: 5.78). Half of the students sought medical help during the acute stage of their reaction. Only 3.2% of the cases have been referred to an allergist for further evaluation.ConclusionThis study, the first of its kind in Turkey, with medical students showed that self‐reported hypersensitivity reactions to drugs is highly prevalent and its prevalence seems to be affected by awareness of the individuals in addition to previously reported risk factors. The education of both patients and physicians on the management of drug hypersensitivity seems to be necessary. Copyright © 2010 John Wiley & Sons, Ltd.
Development of ultra‐thin tunneling oxides and Si/SiO2 nanostructures for the application in silicon solar cells
Authors: Malguth Enno , Roczen Maurizio , Gref Orman , Schoepke Andreas , Schmidt Manfred 
Published: December 2010

AbstractThe synthesis of Si/SiO2 nanostructures for the application as hetero‐emitter and passivation layer in high‐efficiency solar cells is explored with the long‐term perspective of exploiting quantum size effects for next‐generation photovoltaics. Ultra‐thin oxides are developed by means of oxidizing crystalline silicon using neutral oxygen atoms supplied by a RF plasma source. These oxides are characterized by an abrupt Si/SiO2 junction and good passivation of Si dangling bonds at the interface, a precondition for the implementation of Si/SiO2 nanostructures in photovoltaic devices. Another decisive issue is carrier transport across the SiO2 barrier which is demonstrated in form of a tunneling current in I–V measurements. Such tunneling oxides on Si(111) wafers are used as substrates for the subsequent deposition of Si nanodots. Nanodot synthesis is accomplished by first depositing a few nanometer thick layer of amorphous Si. During a subsequent recrystallization step at T > 600 °C, the surface tension between c‐Si and SiO2 causes a dewetting and, thus, the formation of crystalline Si nanodots, the size of which can be controlled by the thickness of the initial amorphous Si layer. Finally the dots are cladded with a shell of tunneling oxide. A close‐packing of spheres with dots stacked on top of each other is approximated by a repetition of this process.
Anomalous effects in the domain‐wall dynamics in magnetic microwires
Authors: Varga Rastislav , Infante German , Richter Kornel , Vazquez Manuel 
Published: December 2010

AbstractIn the present contribution, we deal with two anomalous effects that have been found in magnetic microwires during the domain‐wall dynamics study. First, there is a negative critical propagation field H0. Its frequency and temperature dependence is dealt in terms of two domain‐wall potential minima separated by the energy barrier. Secondly, it is a negative domain‐wall mobility S that appears as a result of stabilization of the domain structure through the structural relaxation. The domain‐wall mobility can be tuned from negative to positive values by properly setting measuring condition (frequency of applied magnetic field, temperature). This gives us also the possibility to obtain the domain‐wall dynamics that is not sensitive to the applied magnetic field H.
Heavy Si doping: The key in heteroepitaxial growth of a‐plane GaN without basal plane stacking faults?
Authors: Wieneke Matthias , Noltemeyer Martin , Bastek Barbara , Rohrbeck Antje , Witte Hartmut , Veit Peter , Bläsing Jürgen , Dadgar Armin , Christen Jürgen , Krost Alois 
Published: December 2010

AbstractIn this paper, we compare the effectiveness of two different methods regarding the reduction of defect densities in heteroepitaxially grown a‐plane GaN by heavy Si doping. The insertion of well‐established in situ SixNy nanomasks leads to locally heavy Si δ‐doped GaN. By increasing the SixNy deposition time in the range from 0 to 300 s the full width at half maxima (FWHM) of the X‐ray diffraction ω‐scans at in‐plane GaN(1${\bar {1}}$00) and GaN(0002) Bragg reflections decreases from 0.55° to 0.24° and from 0.45° to 0.16°, respectively. When growing without any SixNy interlayer but instead with continuously heavy Si‐doping, these values are further decreased to 0.13° and 0.15°, respectively. By measuring several higher order reflections and detailed evaluation of the ω‐scan broadening in Williamson–Hall‐plots (WHPs) a considerable reduction in defect densities and no hint of basal plane stacking faults (BSFs) were found for the heavy Si doped a‐plane GaN sample. To verify this result the micro‐structural properties of this sample were additionally investigated by transmission electron microscopy and cathodoluminescence (CL).
Theoretical study on photon–phonon coupling at (001)‐(2 × 1) surfaces of Ge and α‐Sn
Authors: Pérez‐Sánchez F. L. , Pérez‐Rodríguez F. 
Published: December 2010

AbstractWe present a study of the far‐infrared reflectance anisotropy spectra for (001) surfaces of Ge and α‐Sn in the (2 × 1) asymmetric dimer geometry, which exhibit a resonance structure associated with the excitation of surface phonon modes. We have employed a theoretical formalism, based on the adiabatic bond‐charge model (ABCM), for computing the far‐infrared reflectance anisotropy spectra. In comparison with previous theoretical results for silicon and diamond surfaces, the resonance structure in the reflectance anisotropy spectrum for Ge(001)‐(2 × 1) turns out to be similar to that observed in the spectrum for the Si(001)‐(2 × 1) surface, whereas the spectrum for α‐Sn(001)‐(2 × 1) surface is noticeably different from the others. We have established a trend of far‐infrared reflectance anisotropy spectra for IV(001) surfaces: the weaker dimer strength, the stronger resonances of low‐frequency surface phonons.
Addition of sulfur radicals to fullerenes
Authors: Denis Pablo A. , Iribarne Federico 
Published: December 2010

AbstractThe addition of oxygen‐centered radicals to fullerenes has been intensively studied due to their role in cell protection against against hydrogen peroxide induced oxidative damage. However, the analogous reaction of sulfur‐centered radicals has been largely overlooked. Herein, we investigate the addition of S‐centered radicals to C50, C60, C70, and C100 fullerenes by means of DFT calculations. The radicals assayed were: S, SH, SCH3, SCH2CH3, SC6H5, SCH2C6H5, and the open‐disulfide SCH2CH2CH2CH2S. Sulfur, the most reactive species, prefers to be attached to a 66‐bond of C60 with a binding energy (Ebind) of 2.4 eV. For the SR radicals the electronic binding energies to C60 are 0.77, 0.74, 0.58, 0.67, and 0.35 eV for SH, SCH3, SCH2CH3, SCH2C6H5, and SC6H5, respectively. The reactivity of C60 toward SR radicals can be increased by lithium doping. For Li@C60, the Ebind is increased by 0.65 eV with respect to C60, but only by 0.33 eV for the exohedral doping. Fullerenes act like free radical sponges. Indeed, the C60‐SR Ebind can be duplicated if two radicals are added in ortho or para positions. The enhanced reactivity because of multiple additions is mostly a local effect, although the addition of one radical makes the whole cage more reactive. Therefore, as observed for hydroxylated fullerenes, they should protect cells from oxidative damage. However, the thiolated fullerenes have one advantage, they can be easily attached to gold nanoparticles. For the addition on pentagon junctions smaller fullerenes like C50 are more reactive than C60. Interestingly, C70 is as reactive as C60, even for the addition on the equatorial belt. For larger fullerenes like C100, reactivity decreases for the carbon atoms belonging to hexagon junctions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Excited state reactivity index theory application for small moieties
Authors: Chatterjee Abhijit 
Published: December 2010

AbstractThis study aims to use the concept of ground‐state reactivity index formalism within density functional theory (DFT) to predict the behavior of the excited state through the response function produced by weak electric field on chlorinated methanes and chlorinated benzenes. A comparison was made between the geometry of ground state and the excited state for those moieties through configuration interaction (CI) method with Austin Model 1 Hamiltonian over the optimized geometry of DFT at the ground state. Results obtained through these two methodologies suggested that in terms of polarizability and heat of formation, DFT can reproduce the excited state qualitatively. Again, those results can be further validated through UV spectral data, generated using CI method. The reactivity index proposition at ground state shows the potential of DFT to simulate excitation. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011
Theoretical investigation on the spectroscopic properties of cyclometallated iridium (III) complexes and the deprotonation influence on them in solution
Authors: Wang Jian , Xia Bao‐Hui , Bai Fu‐Quan , Sun Lei , Zhang Hong‐Xing 
Published: December 2010

AbstractElectronic structures and spectroscopic properties of mixed‐ligand cyclometallated iridium complexes with general formula [Ir(NˆC)2(NˆN)]+ (NˆC = 2‐phenylpyridine, NˆN = Hcmbpy = 4‐carboxyl‐4′‐methyl‐2,2′‐bipyridine, 1; H2dcbpy = 4,4′‐dicarboxyl‐2,2′‐bipyridine, 2) were studied theoretically. The geometries of the complexes in ground and excited state were optimized at B3LYP and CIS levels, respectively. The absorption and emission of the complexes in CH3CN solutions were calculated by time‐dependent density functional theory (TD‐DFT) with the PCM solvent model. The calculated absorptions and emissions of the complexes are in good agreement with the measured results. The deprotonation influence on the electronic structure and the optical properties of 2 was also investigated. The results indicate that the deprotonation which occurs on the COOH groups influences the geometries of the complexes in ground and excited state slightly but leads to significant blue‐shifts in low energy absorption and emission maximum. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Liquid chromatography/tandem mass spectrometry sensitivity enhancement via online sample dilution and trapping: applications in microdosing and dried blood spot (DBS) bioanalysis
Authors: Li Fumin , Zulkoski John P. , Ding Jie , Brown Wes , Addison Tom 
Published: December 2010

AbstractA simple online sample dilution, enrichment, and cleanup technique was developed for sensitive microdosing and dried blood spot (DBS) liquid chromatography/tandem mass spectrometric (LC/MS/MS) bioanalysis. Samples are diluted online with water and enriched in a trap column which is subsequently switched inline with the analytical column. Excellent lansoprazole (in acetonitrile) peak shape is maintained even with an 80‐µL injection. In comparison, similar chromatographic peaks were observed only when a small volume of the same solution, i.e., 1 µL, was injected on a regular high‐performance liquid chromatography (HPLC) system, where an injection of 5 µL resulted in severe peak fronting. A substantial enhancement in sensitivity is realized in the trapping mode using large injection volumes. The trap column is washed at the beginning and at the end of each injection with aqueous and organic solvent respectively to remove matrix components. This ultimately leads to reduction of matrix effects and mass spectrometer noise, thus facilitating the utilization of protein precipitation as the sample preparation for plasma samples. A lower limit of quantitation (LLOQ) of 0.5 pg/mL was demonstrated for lansoprazole in human plasma with a signal‐to‐noise (S/N) ratio of 13 using a 100 µL injection. Excellent intra‐day precision and accuracy were established for lansoprazole in human plasma with good linearity (R2 > 0.999) from 0.5 to 500 pg/mL. This level of LLOQ makes LC/MS/MS a practical alternative for microdosing bioanalysis, where the dose is typically 100 times lower than the therapeutic dose. The same technique was applied to quantitate lansoprazole in human whole blood employing DBS technology. With a single 3‐mm punch, i.e. ∼2 µL of whole blood or ∼1 µL plasma, a LLOQ of 0.1 ng/mL showed sufficient S/N ratio (40) for lansoprazole when 75 µL of extract was injected. In all, the online sample dilution, cleanup, and enrichment technique demonstrated the practical utility of LC/MS/MS in microdosing and DBS bioanalysis. Copyright © 2010 John Wiley & Sons, Ltd.
Two tools for applying chromatographic retention data to the mass‐based identification of peptides during hydrogen/deuterium exchange experiments by nano‐liquid chromatography/matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Gershon P. D. 
Published: December 2010

AbstractTwo tools are described for integrating LC elution position with mass‐based data in hydrogen‐deuterium exchange (HDX) experiments by nano‐liquid chromatography/matrix‐assisted laser desorption/ionization mass spectrometry (nanoLC/MALDI‐MS, a novel approach to HDX‐MS). The first of these, ‘TOF2H‐Z Comparator’, highlights peptides in HDX experiments that are potentially misidentified on the basis of mass alone. The program first calculates normalized values for the organic solvent concentration responsible for the elution of ions in nanoLC/MALDI HDX experiments. It then allows the solvent gradients for the multiple experiments contributing to an MS/MS‐confirmed peptic peptide library to be brought into mutual alignment by iteratively re‐modeling variables among LC parameters such as gradient shape, solvent species, fraction duration and LC dead time. Finally, using the program, high‐probability chromatographic outliers can be flagged within HDX experimental data. The role of the second tool, ‘TOF2H‐XIC Comparator’, is to normalize the LC chromatograms corresponding to all deuteration timepoints of all HDX experiments of a project, to a common reference. Accurate normalization facilitates the verification of chromatographic consistency between all ions whose spectral segments contribute to particular deuterium uptake plots. Gradient normalization in this manner revealed chromatographic inconsistencies between ions whose masses were either indistinguishable or separated by precise isotopic increments. Copyright © 2010 John Wiley & Sons, Ltd.
Examination of the translocation of sulfonylurea herbicides in sunflower plants by matrix‐assisted laser desorption/ionisation mass spectrometry imaging
Authors: Anderson David M. G. , Carolan Vikki A. , Crosland Susan , Sharples Kate R. , Clench Malcolm R. 
Published: December 2010

AbstractPesticides are widely used in agriculture to control weeds, pests and diseases. Successful control is dependent on the compound reaching the target site within the organism after spray or soil application. Conventional methods for determining uptake and movement of herbicides and pesticides include autoradiography, liquid scintillation and chromatographic techniques such as high‐performance liquid chromatography (HPLC). Autoradiography using radiolabelled compounds provides the best indication of a compound's movement within the plant system. Autoradiography is an established technique but it relies on the synthesis of radiolabelled compounds. The distribution of four sulfonylurea herbicides in sunflower plants has been studied 24 h after foliar application. The use of matrix‐assisted laser desorption/ionisation mass spectrometry imaging (MALDI‐MSI) images of protonated molecules and fragment ions (resulting from fragmentation at the urea bond within the sulfonylurea herbicides) has provided evidence for translocation above and below the application point. The translocation of nicosulfuron and azoxystrobin within the same plant system has also been demonstrated following their application to the plant stem. This study provides evidence that MALDI‐MSI has great potential as an analytical technique to detect and assess the foliar, root and stem uptake of agrochemicals, and to reveal their distribution through the plant once absorbed and translocated. Copyright © 2010 John Wiley & Sons, Ltd.
Atmospheric pressure‐electron capture dissociation of peptides using a modified PhotoSpray ion source
Authors: Robb Damon B. , Rogalski Jason C. , Kast Jürgen , Blades Michael W. 
Published: December 2010

AbstractAn improved in‐source atmospheric pressure‐electron capture dissociation (AP‐ECD) method is described. Building upon the early example of Laprévote's group, photoelectrons generated within a commercial PhotoSpray atmospheric pressure photoionization source are used to induce ECD of multiply charged peptide ions originating from an upstream heated nebulizer device. To attain high sensitivity, the method makes use of a novel electropneumatic‐heated nebulizer to assist in the creation and transmission of multiply charged ions from sample solutions. Here, we demonstrate that readily interpretable AP‐ECD spectra of infused peptides can be acquired from 100 fmol sample consumed, on a chromatographic time scale, using a conventional quadrupole time‐of‐flight (Q‐ToF) mass spectrometer otherwise incapable of ECD/ETD experiments. Though much work remains to be done to develop and characterize the method, the results indicate that AP‐ECD has the potential to be a practical new tool for the mass spectrometric analysis of peptides and proteins. Copyright © 2010 John Wiley & Sons, Ltd.
Charge‐state‐derivation ion detection using a super‐conducting nanostructure device for mass spectrometry
Authors: Suzuki K. , Ohkubo M. , Ukibe M. , Chiba‐Kamoshida K. , Shiki S. , Miki S. , Wang Z. 
Published: December 2010

AbstractMass spectrometry (MS) is a method of analyzing ions based on their mass/charge (m/z) ratios. The m/z peak identification requires speculation on the ionic unit‐charge states. This problem can be solved by using superconducting junction devices to measure the kinetic energies of single molecules. However, the kinetic energy measurement is followed by the dead time of 1–20 µs, which is fatally slow for modern high‐resolution time‐of‐flight (TOF) analyzers. In this paper, we demonstrate that a superconducting nano‐stripline detector (SSLD) composed of a 10‐nm‐thick and 800‐nm‐wide NbN strip realizes the charge‐state derivation, and furthermore satisfies the ideal MS detector specifications such as a nano‐second response, a short recovery time, a wide mass range, and no noise. Copyright © 2010 John Wiley & Sons, Ltd.
A comparison of the fragmentation pathways of [CuII(Ma)(Mb)]•2+ complexes where Ma and Mb are peptides containing either a tryptophan or a tyrosine residue
Authors: Ke Yuyong , Aribi Houssain El , Siu Chi‐Kit , Siu K.W. Michael , Hopkinson Alan C. 
Published: December 2010

Abstract[CuII(Ma)(Mb)]•2+ complexes, where Ma and Mb are dipeptides or tripeptides each containing either a tryptophan (W) or tyrosine (Y) residue, have been examined by means of electrospray tandem mass spectrometry. Collision‐induced dissociations (CIDs) of complexes containing identical peptides having a tryptophan residue generated abundant radical cations of the peptides; by contrast, for complexes containing peptides having a tyrosine residue, the main fragmentation channel is dissociative proton transfer to give [Ma + H]+ and [CuII(Mb – H)]•+. When there are two different peptides in the complex, each containing a tryptophan residue, radical cations are again the major products, with their relative abundances depending on the locations of the tryptophan residue in the peptides. In the CIDs of mixed complexes, where one peptide contains a tryptophan residue and the other a tyrosine residue, the main fragmentation channel is formation of the radical cation of the tryptophan‐containing peptide and not proton transfer from the tyrosine‐containing peptide to give a protonated peptide. Copyright © 2010 John Wiley & Sons, Ltd.