bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene variants of the renin–angiotensin system and hypertension: from a trough of disillusionment to a welcome phase of enlightenment?
Authors: Norton Gavin R. , Brooksbank Richard , Woodiwiss Angela J.
Published: January 2010

There is substantial evidence to suggest that BP (blood pressure) is an inherited trait. The introduction of gene technologies in the late 1980s generated a sharp phase of over-inflated prospects for polygenic traits such as hypertension. Not unexpectedly, the identification of the responsible loci in human populations has nevertheless proved to be a considerable challenge. Common variants of the RAS (renin–angiotensin system) genes, including of ACE (angiotensin-converting enzyme) and AGT (angiotensinogen) were some of the first shown to be associated with BP. Presently, ACE and AGT are the only gene variants with functional relevance, where linkage studies showing relationships with hypertension have been reproduced in some studies and where large population-based and prospective studies have demonstrated these genes to be predictors of hypertension or BP. Nevertheless, a lack of reproducibility in other linkage and association studies has generated scepticism that only a concerted effort to attempt to explain will rectify. Without these explanations, it is unlikely that this knowledge will translate into the clinical arena. In the present review, we show that many of the previous concerns in the field have been addressed, but we also argue that a considerable amount of careful thought is still required to achieve enlightenment with respect to the role of RAS genes in hypertension. We discuss whether the previously identified problems of poor study design have been completely addressed with regards to the impact of ACE and AGT genes on BP. In the context of RAS genes, we also question whether the significance of ‘incomplete penetrance’ through associated environmental, phenotypic or physiological effects has been duly accounted for; whether appropriate consideration has been given to epistatic interactions between genes; and whether future RAS gene studies should consider variation across the gene by evaluating ‘haplotypes’.
Broadband 308 nm vibrational Raman spectroscopy of gaseous species using a potassium hydrogen phthalate liquid filter and polarization fluorescence suppression
Authors: Saunders J. E. A. , Davy M. H.
Published: January 2010

Broadband XeCl excimer lasers operating at 308 nm are not currently used in the field of gas phase vibrational Raman spectroscopy (VRS). An explanation as to why alternative wavelengths, and in particular tuneable, narrowband lasers are currently preferred for gas phase VRS is presented in addition to demonstrating a setup which makes the XeCl laser a viable alternative when considering excitation sources for VRS. A solution of potassium hydrogen phthalate is shown to be a practical low-pass liquid filter and to reduce substantially the effects of Rayleigh scattering on collected Raman spectra. The use of a commercial beam polarizer is also shown to be effective in suppressing background fluorescence that otherwise necessitates the use of expensive tuneable, narrowband lasers when performing VRS with sources of background fluorescence. Finally, an unconventional excitation beam arrangement is shown to produce viable Raman spectra from which species concentrations and distributions can be determined.
Note: Anodic bonding with cooling of heat-sensitive areas
Authors: Vesborg Peter C. K. , Olsen Jakob L. , Henriksen Toke R. , Chorkendorff Ib , Hansen Ole
Published: January 2010

Anodic bonding of silicon to glass always involves heating the glass and device to high temperatures so that cations become mobile in the electric field. We present a simple way of bonding thin silicon samples to borosilicate glass by means of heating from the glass side while locally cooling heat-sensitive areas from the silicon side. Despite the high thermal conductivity of silicon, this method allows a strong anodic bond to form just millimeters away from areas essentially at room temperature.
Absolute response of Fuji imaging plate detectors to picosecond-electron bunches
Authors: Zeil K. , Kraft S. D. , Jochmann A. , Kroll F. , Jahr W. , Schramm U. , Karsch L. , Pawelke J. , Hidding B. , Pretzler G.
Published: January 2010

The characterization of the absolute number of electrons generated by laser wakefield acceleration often relies on absolutely calibrated FUJI imaging plates (IP), although their validity in the regime of extreme peak currents is untested. Here, we present an extensive study on the dependence of the sensitivity of BAS-SR and BAS-MS IP to picosecond electron bunches of varying charge of up to 60 pC, performed at the electron accelerator ELBE, making use of about three orders of magnitude of higher peak intensity than in prior studies. We demonstrate that the response of the IPs shows no saturation effect and that the BAS-SR IP sensitivity of 0.0081 photostimulated luminescence per electron number confirms surprisingly well data from previous works. However, the use of the identical readout system and handling procedures turned out to be crucial and, if unnoticed, may be an important error source.
Simultaneous mid-range power transfer to multiple devices
Authors: Kurs André , Moffatt Robert , Soljačić Marin
Published: January 2010

Electromagnetic resonators strongly coupled through their near-fields [A. Karalis, J. D. Joannopoulos, and M. Soljačić, Ann. Phys. 323, 34 (2008); A. Kurs, A. Karalis, R. Moffatt, J. D. Joannopoulos, P. Fisher, and M. Soljačić, Science 317, 83 (2007)] are able to achieve efficient wireless power transfer from a source to a device separated by distances multiple times larger than the characteristic sizes of the resonators. This midrange approach is therefore suitable for remotely powering several devices from a single source. We explore the effect of adding multiple devices on the tuning and overall efficiency of the power transfer, and demonstrate this scheme experimentally for the case of coupling objects of different sizes: a large source (1 m2 in area) powering two smaller devices (each ≃0.07 m2 in area).
Understanding the role of tunneling barriers in organic spin valves by hard x-ray photoelectron spectroscopy
Authors: Borgatti F. , Bergenti I. , Bona F. , Dediu V. , Fondacaro A. , Huotari S. , Monaco G. , MacLaren D. A. , Chapman J. N. , Panaccione G.
Published: January 2010

We present an ex situ, nondestructive chemical characterization of deeply buried organic-inorganic interfaces using hard x-ray photoelectron spectroscopy. Co/Alq3 and Co/AlOx/Alq3 interfaces were studied in order to determine the role of a thin (1–2 nm) AlOx interdiffusion barrier in organic spin valves. Interfacial Alq3, 15 nm below the surface, exhibits strong sensitivity to the electronic structure of the interfacial region and to the presence of the AlOx. In addition to reducing Co–Alq3 interdiffusion, we find that the barrier prevents charge donation from the Co to the interfacial Alq3, thus preventing the formation of Alq3 anions within the interface region.
Electric-pulse-induced resistance change in Ba0.5Sr0.5Co0.2Fe0.8O3 thin films
Authors: Xing Z. W. , Wu N. J. , Ignatiev A.
Published: January 2010

Five-component perovskite Ba0.5Sr0.5Co0.2Fe0.8O3 (BSCFO) thin films are reported to have polarized electrical-pulse-induced resistance (EPIR) change at room temperature. Such an EPIR change is attributed to a combined effect of the resistance change in the Schottky barrier and the oxygen ion/vacancy movement near the interface. In the BSCFO, the lower threshold voltage of the electric pulse that leads to nonvolatile resistive changes is closely related to its higher oxygen permeability.
Organic-inorganic heterojunction field-effect transistors
Authors: Wang Haibo , Liu Zengtao , Lo Ming Fai , Ng Tsz Wai , Lee Chun-Sing , Yan Donghang , Lee Shuit-Tong
Published: January 2010

Field-effect transistors with organic-inorganic heterojunctions of molybdenum trioxide (MoO3)/pentacene and MoO3/copper-phthalocyanine (CuPc) as active layers were prepared and analyzed. These transistors showed normally-on operation mode and a shift of threshold voltage comparing to the corresponding single-layer organic device. The interfacial electronic structures of MoO3/pentacene and MoO3/CuPc heterojunctions were investigated by ultraviolet photoemission spectroscopy. Significant electron energy level bending and space charge regions of high conductivity were observed at the heterojunction. Formation of the organic-inorganic heterojunctions and characteristics of the corresponding field-effect transistors were analyzed by considering charge exchange at heterojunction interfaces.
Threshold collision-induced dissociation of Sr2+(H2O)x complexes (x=1–6): An experimental and theoretical investigation of the complete inner shell hydration energies of Sr2+
Authors: Carl D. R. , Chatterjee B. K. , Armentrout P. B.
Published: January 2010

The sequential bond energies of Sr2+(H2O)x complexes, where x=1–6, are determined by threshold collision-induced dissociation using a guided ion beam tandem mass spectrometer equipped with an electrospray ionization source. The electrospray source produces an initial distribution of Sr2+(H2O)x complexes, where x=6–9. Smaller Sr2+(H2O)x complexes, where x=1–5, are accessed using a recently developed in-source fragmentation technique that takes place in the high pressure region of a rf-only hexapole ion guide. This work constitutes the first experimental study for the complete inner shell of any multiply charged ion. The kinetic energy dependent cross sections are determined over a wide energy range to monitor all possible dissociation products and are modeled to obtain 0 and 298 K binding energies for loss of a single water molecule. These binding energies decrease monotonically for the Sr2+(H2O) complex to Sr2+(H2O)6. Our experimental results agree well with previous literature results obtained by equilibrium and kinetic studies for x=5 and 6. Because there has been limited theory for the hydration of Sr2+, we also present an in-depth theoretical study on the energetics of the Sr2+(H2O)x systems by employing several levels of theory with multiple effective core potentials for Sr and different basis sets for the water molecules.
Superhydrophobic surfaces with nanofibers or nanorods based on thiophene derivatives
Authors: Jia Zhixin , Liu Mingxian , Liu Fang , Luo Yuanfang , Jia Demin , Guo Baochun
Published: January 2010

Fabricating superhydrophobic surfaces via self-assembly of organic conjugated small molecules is realized by spray-drying the thiophene derivates organic solutions. Formation of microsized pores and arrayed nanofibers or nanorods on the surfaces is responsible for the superhydrophobicity of the coatings. This technique can be applied for fabrication of large area superhydrophobic surfaces with conjugated molecules on different substrates.
Subwavelength plasmonic waveguides based on ZnO nanowires and nanotubes: A theoretical study of thermo-optical properties
Authors: Zhang Xiao-Yang , Hu A. , Zhang Tong , Xue Xiao-Jun , Wen J. Z. , Duley W. W.
Published: January 2010

We show theoretically that plasmonic waveguide structures in ZnO nanowires and nanotubes working at optical frequencies can achieve photonic waveguiding in a subdiffraction limit. The output intensity distribution, propagation length, and thermo-optical properties with different waveguide configurations are investigated. Our results show that these waveguides have the potential to develop either high performance thermally controlled nanoscale plasmonic devices or thermally insensitive waveguides by optimizing waveguide configurations.
Slow Debye-type peak observed in the dielectric response of polyalcohols
Authors: Bergman Rikard , Jansson Helén , Swenson Jan
Published: January 2010

Dielectric relaxation spectroscopy of glass forming liquids normally exhibits a relaxation scenario that seems to be surprisingly general. However, the relaxation dynamics is more complicated for hydrogen bonded liquids. For instance, the dielectric response of monoalcohols is dominated by a mysterious Debye-like process at lower frequencies than the structural α-relaxation that is normally dominating the spectra of glass formers. For polyalcohols this process has been thought to be absent or possibly obscured by a strong contribution from conductivity and polarization effects at low frequencies. We here show that the Debye-like process, although much less prominent, is also present in the response of polyalcohols. It can be observed in the derivative of the real part of the susceptibility or directly in the imaginary part if the conductivity contribution is reduced by covering the upper electrode with a thin Teflon layer. We report on results from broadband dielectric spectroscopy studies of several polyalcohols: glycerol, xylitol, and sorbitol. The findings are discussed in relation to other experimental observations of ultraslow (i.e., slower than the viscosity related α-relaxation) dynamics in glass formers.
Ternary logic implemented on a single dopant atom field effect silicon transistor
Authors: Klein M. , Mol J. A. , Verduijn J. , Lansbergen G. P. , Rogge S. , Levine R. D. , Remacle F.
Published: January 2010

We provide an experimental proof of principle for a ternary multiplier realized in terms of the charge state of a single dopant atom embedded in a fin field effect transistor (Fin-FET). Robust reading of the logic output is made possible by using two channels to measure the current flowing through the device and the transconductance. A read out procedure that allows for voltage gain is proposed. Long numbers can be multiplied by addressing a sequence of Fin-FET transistors in a row.
Finite element analysis of ring-shaped emission profile in plasma bullet
Authors: Sakiyama Yukinori , Graves David B. , Jarrige Julien , Laroussi Mounir
Published: January 2010

Using a one-way coupled model of neutral gas flow and plasma dynamics we report a mechanism to explain the ring-shaped emission pattern that has been observed experimentally in plasma bullets at atmospheric pressure. We solve a fluid model with the local field approximation in one-dimensional cylindrical coordinates, corresponding to a cross-section of a plasma bullet. Pulselike uniform electric field is assumed to be applied perpendicular to the simulation domain. Time and spatially resolved spectroscopic measurements support the simulation results.
Three-dimensional carbon nanowall field emission arrays
Authors: Stratakis E. , Giorgi R. , Barberoglou M. , Dikonimos Th. , Salernitano E. , Lisi N. , Kymakis E.
Published: January 2010

This letter reports on the fabrication of regular arrays of three dimensional graphitic structures, by growing carbon nanowalls on forests of conical Si microspikes. The high field enhancement achieved by this hierarchical growth process indicates a potential for electron emission applications. Experiments show that the field emission performance and long-term stability of the structures is by far superior to that of planar carbon nanowall mats and comparable to that reported for optimized carbon nanotube based emitters. The improved field emission properties of the fabricated arrays are attributed to the dual micro and nanomorphology of the emitters, involving a two-scale enhancement process.
Acoustic metamaterial panels for sound attenuation in the 50–1000 Hz regime
Authors: Yang Z. , Dai H. M. , Chan N. H. , Ma G. C. , Sheng Ping
Published: January 2010

We show experimentally that thin membrane-type acoustic metamaterials can serve as a total reflection nodal surface at certain frequencies. The small decay length of the evanescent waves at these frequencies implies that several membrane panels can be stacked to achieve broad-frequency effectiveness. We report the realization of acoustic metamaterial panels with thickness ≤15 mm and weight ≤3 kg/m2 demonstrating 19.5 dB of internal sound transmission loss (STL) at around 200 Hz, and stacked panels with thickness ≤60 mm and weight ≤15 kg/m2 demonstrating an average STL of >40 dB over a broad range from 50 to 1000 Hz.
High-resolution electron spectroscopy and structures of lithium-nucleobase (adenine, uracil, and thymine) complexes
Authors: Krasnokutski Serge A. , Lee Jung Sup , Yang Dong-Sheng
Published: January 2010

Li complexes of adenine, uracil, and thymine were produced by laser vaporization of rods made of Li and nucleobase powders in a metal-cluster beam source and studied by pulsed-field-ionization zero-electron-kinetic-energy (ZEKE) spectroscopy and density functional theory calculations. The ZEKE measurements determined the adiabatic ionization energies of the three neutral complexes and frequencies of several vibrational modes for the metal-adenine and -uracil ions. The measured spectra were compared with spectral simulations to determine the preferred metal binding sites. For adenine, the most stable structure is formed by Li/Li+ bidentately binding to both the N7 atom of the imidazole ring and the NH2 group of the pyrimidine ring. For uracil and thymine, the ideal site for Li/Li+ coordination is the O4 atom. Although it has only a small effect on the geometries of uracil and thymine, lithium coordination forces the rotation of the NH2 group out of the adenine plane. The adiabatic ionization energies of the three complexes follow the trend of uracil (33910±5 cm−1)>thymine(33386±5 cm−1)>adenine(32240±5 cm−1), whereas their metal-ligand bond dissociation energies are about the same, (92–97) ±6 kJ mol−1. For all three complexes, the neutral bond energies are smaller than those of the corresponding ions due to a weaker electrostatic interaction and stronger electron repulsion.
NMR and XAS reveal an inner-sphere metal binding site in the P4 helix of the metallo-ribozyme ribonuclease P
Authors: Koutmou Kristin S. , Casiano-Negroni Anette , Getz Melissa M. , Pazicni Samuel , Andrews Andrew J. , Penner-Hahn James E. , Al-Hashimi Hashim M. , Fierke Carol A.
Published: January 2010

Functionally critical metals interact with RNA through complex coordination schemes that are currently difficult to visualize at the atomic level under solution conditions. Here, we report a new approach that combines NMR and XAS to resolve and characterize metal binding in the most highly conserved P4 helix of ribonuclease P (RNase P), the ribonucleoprotein that catalyzes the divalent metal ion-dependent maturation of the 5′ end of precursor tRNA. Extended X-ray absorption fine structure (EXAFS) spectroscopy reveals that the Zn
2+
bound to a P4 helix mimic is six-coordinate, with an average Zn-O/N bond distance of 2.08 Å. The EXAFS data also show intense outer-shell scattering indicating that the zinc ion has inner-shell interactions with one or more RNA ligands. NMR Mn
2+
paramagnetic line broadening experiments reveal strong metal localization at residues corresponding to G378 and G379 in
B. subtilis
RNase P. A new “metal cocktail” chemical shift perturbation strategy involving titrations with

, Zn
2+
, and

confirm an inner-sphere metal interaction with residues G378 and G379. These studies present a unique picture of how metals coordinate to the putative RNase P active site in solution, and shed light on the environment of an essential metal ion in RNase P. Our experimental approach presents a general method for identifying and characterizing inner-sphere metal ion binding sites in RNA in solution.
Modeling the emergence of universality in color naming patterns
Authors: Baronchelli Andrea , Gong Tao , Puglisi Andrea , Loreto Vittorio
Published: January 2010

The empirical evidence that human color categorization exhibits some universal patterns beyond superficial discrepancies across different cultures is a major breakthrough in cognitive science. As observed in the World Color Survey (WCS), indeed, any two groups of individuals develop quite different categorization patterns, but some universal properties can be identified by a statistical analysis over a large number of populations. Here, we reproduce the WCS in a numerical model in which different populations develop independently their own categorization systems by playing elementary language games. We find that a simple perceptual constraint shared by all humans, namely the human Just Noticeable Difference (JND), is sufficient to trigger the emergence of universal patterns that unconstrained cultural interaction fails to produce. We test the results of our experiment against real data by performing the same statistical analysis proposed to quantify the universal tendencies shown in the WCS [Kay P & Regier T. (2003)Proc. Natl. Acad. Sci. USA100: 9085-9089], and obtain an excellent quantitative agreement. This work confirms that synthetic modeling has nowadays reached the maturity to contribute significantly to the ongoing debate in cognitive science.
Rescue of paclitaxel sensitivity by repression of Prohibitin1 in drug-resistant cancer cells
Authors: Patel Nish , Chatterjee Sabarni K. , Vrbanac Vladimir , Chung Ivy , Mu Chunyao Jenny , Olsen Rachelle R. , Waghorne Carol , Zetter Bruce R.
Published: January 2010

Paclitaxel has emerged as a front line treatment for aggressive malignancies of the breast, lung, and ovary. Successful therapy of cancer is frequently undermined by the development of paclitaxel resistance. There is a growing need to find other therapeutic targets to facilitate treatment of drug-resistant cancers. Using a proteomics approach, elevated levels of Prohibitin1 (PHB1) and GSTπ were found associated with paclitaxel resistance in discrete subcellular fractions of two drug-resistant sublines relative to their sensitive sublines. Immunofluorescence staining and fractionation studies revealed increased levels of PHB1 on the surface of resistant cell lines. Transiently silencing either PHB1 or GSTπ gene expression using siRNA in the paclitaxel-resistant cancer cell sublines partially sensitized these cells toward paclitaxel. Intriguingly, silencing PHB1 but not GSTπ resulted in activation of the intrinsic apoptosis pathway in response to paclitaxel. Similarly, stably silencing either PHB1 or GSTπ significantly improved paclitaxel sensitivity in A549TR cells both in vitro and in vivo. Our results indicate that PHB1 is a mediator of paclitaxel resistance and that this resistance may depend on the cellular localization of the protein. We suggest PHB1 as a potential target for therapeutic strategies for the treatment of drug-resistant tumors.
Flow enhances photosynthesis in marine benthic autotrophs by increasing the efflux of oxygen from the organism to the water
Authors: Mass Tali , Genin Amatzia , Shavit Uri , Grinstein Mor , Tchernov Dan
Published: January 2010

Worldwide, many marine coastal habitats are facing rapid deterioration due in part to human-driven changes in habitat characteristics, including changes in flow patterns, a factor known to greatly affect primary production in corals, algae, and seagrasses. The effect of flow traditionally is attributed to enhanced influx of nutrients and dissolved inorganic carbon (DIC) across the benthic boundary layer from the water to the organism however, here we report that the organism’s photosynthetic response to changes in the flow is nearly instantaneous, and that neither nutrients nor DIC limits this rapid response. Using microelectrodes, dual-pulse amplitude-modulated fluorometry, particle image velocimetry, and real time mass-spectrometry with the common scleractinian coralFavia veroni, the algaGracilaria cornea, and the seagrassHalophila stipulacea, we show that this augmented photosynthesis is due to flow-driven enhancement of oxygen efflux from the organism to the water, which increases the affinity of the RuBisCO to CO2. No augmentation of photosynthesis was found in the absence of flow or when flow occurred, but the ambient concentration of oxygen was artificially elevated. We suggest that water motion should be considered a fundamental factor, equivalent to light and nutrients, in determining photosynthesis rates in marine benthic autotrophs.
A role for FKBP52 in Tau protein function
Authors: Chambraud Béatrice , Sardin Elodie , Giustiniani Julien , Dounane Omar , Schumacher Michael , Goedert Michel , Baulieu Etienne-Emile
Published: January 2010

Tau is a microtubule-associated protein, which is widely expressed in the central nervous system, predominantly in neurons, where it regulates microtubule dynamics, axonal transport, and neurite outgrowth. The aberrant assembly of Tau is the hallmark of several human neurodegenerative diseases, collectively known as tauopathies. They include Alzheimer’s disease, Pick’s disease, progressive supranuclear palsy, and frontotemporal dementia and parkinsonism linked to chromosome 17. Several abnormalities in Tau, such as hyperphosphorylation and aggregation, alter its function and are central to the pathogenic process. Here, we describe biochemical and functional interactions between FKBP52 and Tau. FKBP52 is a member of the FKBP (FK506-binding protein) family that comprises intracellular protein effectors of immunosuppressive drugs (such as FK506 and rapamycin). We found that FKBP52, which is abundant in brain, binds directly and specifically to Tau, especially in its hyperphosphorylated form. The relevance of this observation was confirmed by the colocalization of both proteins in the distal part of the axons of cortical neurons and by the antagonistic effect of FKBP52 on the ability of Tau to promote microtubule assembly. Overexpression of FKBP52 in differentiated PC12 cells prevented the accumulation of Tau and resulted in reduced neurite length. Taken together, these findings indicate a role for FKBP52 in Tau function and may help to decipher and modulate the events involved in Tau-induced neurodegeneration.
Two physically, functionally, and developmentally distinct peritoneal macrophage subsets
Authors: Ghosn Eliver Eid Bou , Cassado Alexandra A. , Govoni Gregory R. , Fukuhara Takeshi , Yang Yang , Monack Denise M. , Bortoluci Karina R. , Almeida Sandro R. , Herzenberg Leonard A. , Herzenberg Leonore A.
Published: January 2010

The peritoneal cavity (PerC) is a unique compartment within which a variety of immune cells reside, and from which macrophages (MØ) are commonly drawn for functional studies. Here we define two MØ subsets that coexist in PerC in adult mice. One, provisionally called the large peritoneal MØ (LPM), contains approximately 90% of the PerC MØ in unstimulated animals but disappears rapidly from PerC following lipopolysaccharide (LPS) or thioglycolate stimulation. These cells express high levels of the canonical MØ surface markers, CD11b and F4/80. The second subset, referred to as small peritoneal MØ (SPM), expresses substantially lower levels of CD11b and F4/80 but expresses high levels of MHC-II, which is not expressed on LPM. SPM, which predominates in PerC after LPS or thioglycolate stimulation, does not derive from LPM. Instead, it derives from blood monocytes that rapidly enter the PerC after stimulation and differentiate to mature SPM within 2 to 4 d. Both subsets show clear phagocytic activity and both produce nitric oxide (NO) in response to LPS stimulation in vivo. However, their responses to LPS show key differences: in vitro, LPS stimulates LPM, but not SPM, to produce NO; in vivo, LPS stimulates both subsets to produce NO, albeit with different response patterns. These findings extend current models of MØ heterogeneity and shed new light on PerC MØ diversity, development, and function. Thus, they introduce a new context for interpreting (and reinterpreting) data from ex vivo studies with PerC MØ.
Attracting AID to targets of somatic hypermutation
Authors: Tanaka Atsushi , Shen Hong Ming , Ratnam Sarayu , Kodgire Prashant , Storb Ursula
Published: January 2010

The process of somatic hypermutation (SHM) of immunoglobulin (Ig) genes requires activation-induced cytidine deaminase (AID). Although mistargeting of AID is detrimental to genome integrity, the mechanism and the cis-elements responsible for targeting of AID are largely unknown. We show that three CAGGTG cis-elements in the context of Ig enhancers are sufficient to target SHM to a nearby transcribed gene. The CAGGTG motif binds E47 in nuclear extracts of the mutating cells. Replacing CAGGTG with AAGGTG in the construct without any other E47 binding site eliminates SHM. The CA versus AA effect requires AID. CAGGTG does not enhance transcription, chromatin acetylation, or overall target gene activity. The other cis-elements of Ig enhancers alone cannot attract the SHM machinery. Collectively with other recent findings, we postulate that AID targets all genes expressed in mutating B cells that are associated with CAGGTG motifs in the appropriate context. Ig genes are the most highly mutated genes, presumably because of multiple CAGGTG motifs within the Ig genes, high transcription activity, and the presence of other cooperating elements in Ig enhancers.
Different patterns of high-energy and low-energy electrons in an atmospheric-pressure microplasma generated by a hairpin resonator
Authors: Tian Wei , Zhu Xi-Ming , Pu Yi-Kang
Published: January 2010

A newly developed device, a hairpin resonator, is used to generate an atmospheric-pressure microplasma with a 1.8 GHz power supply in argon. The two-dimensional distributions of emission lines in such a microplasma are obtained by a spatially resolved optical system. For the first time, it is found that the distributions of high-energy and low-energy electrons have different patterns. The density distribution of the high-energy electrons (with energy higher than that of argon 2p levels) is obtained from the line intensity, while the density of the low-energy ones (approximately equal to the total electron density) is deduced from the emission line ratios. The difference in distribution between the two groups of electrons is related to the different energy-loss characteristic lengths.
Room-temperature magnetoelectric coupling in Bi4(Ti1Fe2)O12−δ system
Authors: Chen X Q , Yang F J , Cao W Q , Wang D Y , Chen K
Published: January 2010

Bi4(Ti1Fe2)O12−δ ceramics were prepared by the conventional solid state reaction method. The sample exhibited ferroelectricity and magnetism simultaneously at room temperature, which was demonstrated by the ferroelectric (2P
r = 4.1 µC cm−2, 2E
c = 42 kV cm−1 at applied electric field 31 kV cm−1) and ferromagnetic (M
r = 3 × 10−3 emu g−1, H
c = 218 Oe) hysteresis loops. Changes of 19.7% and 17.1% in, respectively, remanent polarization and magnetization after poling the sample in magnetic and dc electric for fields 10 min were evidence of magnetoelectric coupling between the electric dipoles and magnetic dipoles at room temperature.
CVD synthesis of polycrystalline magnetite thin films: structural, magnetic and magnetotransport properties
Authors: Mantovan R , Lamperti A , Georgieva M , Tallarida G , Fanciulli M
Published: January 2010

Magnetite (Fe3O4) is predicted to be half metallic at room temperature (RT) and it shows the highest Curie temperature among oxides. The use of Fe3O4 thin films is therefore promising for spintronic devices such as magnetic tunnel junctions (MTJs) and magnetoresistive sensors. The structural, magnetic and magnetotransport properties of magnetite are reported to be strongly dependent on the growth conditions. We have developed a very simple deposition chamber for growing thin magnetite films via a chemical vapour deposition (CVD) process based on the Fe3(CO)12 carbonyl precursor. The structural, morphological, and magnetic properties of the as deposited Fe3O4 films have been investigated by means of time of flight secondary ion mass spectrometry, grazing incidence x-ray diffraction, x-ray reflectivity, atomic force microscopy, conversion electron Mössbauer spectroscopy and superconducting quantum interference device magnetometry. Magnetotransport measurements show magnetoresistance up to −2.4% at RT at the maximum applied field of 1.1 T. Resistivity measurements in the 100–300 K temperature range reveal that the magnetotransport properties of the Fe3O4 films are governed by inter-granular tunnelling of the spin-polarized electrons. The spin polarization is estimated to be around −16%. A possible route for increasing the spin-polarized performances of our magnetite films is proposed. We have also deposited Fe3O4/MgO/Co stacks by using a combined CVD and atomic layer-deposition process. The trilayer's hysteresis curve evidences the presence of two distinct switching fields making it promising for magnetite-based MTJ applications.
Spark cross size in a sliding submicrosecond discharge of opposite polarities in rare gases: experiment and application of ionization wave front propagation theory to analysis
Authors: Trusov K K
Published: January 2010

The results from an experimental measurement of the spark channel radius in a sliding multichannel discharge of opposite polarities in Ne, Ar and Xe are presented and discussed. The experiments were performed at submicrosecond discharge pulse duration (90–190 ns current pulse FWHM) and gas pressures of 30 and 100 kPa, with alumina ceramics as the dielectric substrate. The data showed the optical radius of the negative polarity spark channels to exceed 1.27–1.6 times those of the positive channels, depending on the gas type and its pressure. The earlier theoretical study by U Ebert, W van Saarloos and C Caroly on the propagation of opposite polarity ionization wave fronts was applied to the analysis of experimental results. From the two approaches of theory, only the ‘non-localized initial conditions’ one, which in addition to the gas impact ionization, drift and diffusion of electrons also takes into account the free initial electrons in the gas ahead of the ionization wave front, is capable of explaining concurrently the experimental observations on positive and negative channel radii, their ratios and the dependence on gas type and pressure. Numerical solutions of the channel expansion equation specified that the expansion speed is governed by both the drift electrons and free electrons generated by a short-range source in a narrow layer around the channel lateral surface. The depth of the latter layer was estimated to be comparable to the expansion wave front depth and, thus, much less than the channel radius.
Ion irradiation stability of multilayered AlN/TiN nanocomposites
Authors: Milosavljević Momir , Peruško Davor , Milinović Velimir , Stojanović Zoran , Zalar Anton , Kovač Janez , Jeynes Chris
Published: January 2010

Structural changes in multilayered AlN/TiN nanocomposites upon Ar+ ion irradiation were investigated. Reactive sputtering was used to deposit (AlN/TiN) × 5 multilayers on Si(1 0 0), to a total thickness of ∼270 nm. Argon was implanted at 200 keV, to 5 × 1015–4 × 1016 ions cm−2. The as-deposited multilayers had a very fine columnar nanocrystalline structure, the width of individual grains was up to ∼10 nm. It was found that this immiscible system exhibits a high ion radiation stability, the AlN and TiN layers remaining well separated, with sharp interfaces. Ion irradiation induced small local density changes and only a slight increase in individual grains, in the region where most damage was deposited by the impact ions. For the highest irradiation fluence there was also some migration of Ti into AlN in this region, which was assigned to excess nitrogen within the AlN layers. Due to these small structural changes, ion irradiation enhanced the mechanical strength of the multilayered nanocomposites.
GaSb quantum dot morphology for different growth temperatures and the dissolution effect of the GaAs capping layer
Authors: Kamarudin M Ahmad , Hayne M , Zhuang Q D , Kolosov O , Nuytten T , Moshchalkov V V , Dinelli F
Published: January 2010

We compare the characteristics of GaSb quantum dots (QDs) grown by molecular beam epitaxy on GaAs at temperatures from 400 to 490 °C. The dot morphology, in terms of size, shape and density, as determined by atomic force microscopy (AFM) on uncapped QDs, was found to be highly sensitive to the growth temperature. Photoluminescence (PL) spectra of capped QDs are also strongly dependent on growth temperature, but for samples with the highest dot density, where the QD luminescence would be expected to be the most intense, it is absent. We attribute this to dissolution of the dots by the capping layer. This explanation is confirmed by AFM of a sample that is thinly capped at 490 °C. Deposition of the capping layer at low temperature resolves this problem, resulting in strong QD PL from a sample with a high dot density.
Trace‐element compositions of single fluid inclusions in the Kofu granite, Japan: Implications for compositions of granite‐derived fluids
Authors: Kurosawa Masanori , Ishii Satoshi , Sasa Kimikazu
Published: January 2010

Fluid inclusions in quartz from miarolitic cavities, pegmatites, and quartz veins in Miocene biotite‐granite plutons, Kofu, Japan, were analyzed by particle‐induced X‐ray emission to examine chemistries and behaviors of granite‐derived fluids in island‐arc granite. Most inclusions are aqueous two‐phase inclusions, and halite‐bearing polyphase inclusions are also observed in quartz veins in the upper part of the plutons. From element contents of fluid inclusions in the miarolitic cavities, the original fluid released from the granite plutons during solidification is inferred to have concentrations of Mn, Fe, Cu, Zn, Ge, Br, Rb, Pb, and Ba of several tens to hundreds of parts per million by weight (ppm) and a salinity of about 10 wt% NaCl equivalent. We estimated the formation conditions of the fluid to have been at about 1.3–1.9 kb and 530–600°C on the basis of the homogenization temperatures of the inclusions and the solidification conditions of the plutons. The polyphase inclusions probably originated from hypersaline fluid by boiling of part of the released fluid during its ascent in the plutons. The polyphase inclusions contain several hundreds to tens of thousands of ppm of Fe and Mn, and tens to several hundreds of ppm of Cu, Zn, Br, Rb, and Pb. The salinities are about 35 wt% NaCl equivalent. Compositional variations in two‐phase inclusions from the miarolitic cavities and quartz veins are primarily explained by mineral precipitation with dilution by surface water exerting a secondary influence. Thus, chemistries and behaviors of the granite‐derived fluids in the plutons can be explained by mineral precipitation, boiling, and dilution of the originally released fluid.
Perianal abscess and fistula‐in‐ano in children: Aetiology, management and outcome
Authors: Ezer Semire Serin , Oğuzkurt Pelin , Ince Emine , Hiçsönmez Akgün
Published: January 2010

Aim:  We aimed to assess our experience in treatment and outcome of perianal abscess and/or fistula‐in‐ano in children.

Method:  The patients who were treated for perianal abscess and/or fistula‐in‐ano from January 2000 to December 2005 were included. Age, sex, duration of symptoms, number and site of the perianal abscess and/or fistula‐in‐ano, treatment modality and recurrences were recorded.

Results:  The study consisted of 39 patients (36 boys) with a mean age of 29 ± 49.1 months. At first examination the diagnosis was perianal abscess in 20 patients, perianal abscess with fistula in five patients and fistula‐in‐ano in 14 patients. No patients had an underlying illness. The primary local treatment of perianal abscess with or without fistula was incision and drainage (with or without antibiotic therapy) in 21 patients, and local care with antibiotic therapy was given to four patients. Of 20 patients with perianal abscess, 17 developed fistula‐in‐ano and three healed. One patient in the perianal abscess group who developed fistula‐in‐ano and two patients in the fistula group were lost to follow‐up. Thirty‐three patients with fistula‐in‐ano underwent surgical treatment either through a fistulotomy or through a fistulectomy. Five (15.1%) patients who experienced recurrent fistula‐in‐ano underwent fistulotomy were completely cured after the second operation.

Conclusion:  Treatment of a perianal abscess either through incision and drainage with antibiotics or through antibiotics alone resulted in a high rate (85%) of fistula formation. Fistula‐in‐ano can be treated either by fistulotomy or by fistulectomy, both of which are associated with a reasonable chance of recurrence of fistula‐in‐ano formation. We obtained good results in our patients through surgical approach (fistulotomy or fistulectomy), for fistula‐in‐ano formed following treatment of perianal abscess.
Does a standardised scoring system of clinical signs reduce variability between doctors' assessments of the potentially dehydrated child?
Authors: Roland Damian , Clarke Colin , Borland Meredith L , Pascoe Elaine M
Published: January 2010

Aims:  Clinical assessment of dehydration in children is often inaccurate. We aimed to determine if a scoring system based on standardised clinical signs would reduce the variability between doctors' assessment of dehydration.

Methods:  A clinical scoring system was developed using seven physiological variables based on previously published research. Estimated percentage dehydration and severity scores were recorded for 100 children presenting to a Paediatric Emergency Department with symptoms of gastroenteritis and dehydration by three doctors of different seniority (resident medical officer, registrar and consultant). Agreement was measured using intra‐class correlation coefficient (ICC) for percentage ratings and total clinical scores and kappa for individual characteristics.

Results:  Estimated percentage dehydration ranged from 0–9%, mean 2.96%, across the three groups. Total clinical scores from 0–10, mean 2.20. There was moderate agreement amongst clinicians for the percentage dehydration (ICC 0.40). The level of agreement on the clinical scoring system was identical (ICC 0.40). Consultants gave statistically lower scores than the other two groups (Consultant (Con) vs. Resident P = 0.001, Con vs. Registrar P = 0.013). There was a marked difference in agreement across characteristics comprising the scoring system, from kappa 0.02 for capillary refill time to 0.42 for neurological status.

Conclusion:  The clinical scoring system used did not reduce the variability of assessment of dehydration compared to doctors' conventional methods. In order to reduce variability improving education may be more important than production of a scoring system as experience appears to be a key determinant in the assessment of a potentially dehydrated child.
Neurofibromatosis 2 with peripheral neuropathies: Electrophysiological, pathological and genetic studies of a Taiwanese family
Authors: Kuo Hung‐Chou , Chen Shyue‐Ru , Jung Shih‐Ming , Wu Chou Yah‐Huei , Huang Chin‐Chang , Chuang Wen‐Li , Wei Kuo‐Chen , Ro Long‐Sun
Published: January 2010

The objective of this study was to assess peripheral nerve involvement and DNA mutation of the neurofibromatosis type 2 (NF2) gene (NF2) in a Taiwanese family with classic NF2. Eleven members (six symptomatic and five asymptomatic) of a family carrying NF2 underwent clinical examination, neuroimaging, and electrophysiological analysis. Mutation and linkage analyses were conducted on DNA samples prepared from peripheral blood (all individuals), a sural nerve biopsy specimen (one symptomatic member), and a tumor specimen (another symptomatic member). Six of the 11 members were diagnosed with classic NF2. DNA sequencing of the tumor specimen demonstrated a frameshift mutation with 756delC on exon 8 of NF2. Three affected subjects showed clinical variability of the neuropathic disorders. Electrophysiological studies demonstrated variation in the disease pattern and severity of peripheral nerve involvement in five affected subjects. The morphometric assessment of the sural nerve biopsy specimen showed a marked reduction in both large myelinated and unmyelinated fibre density and increased density of non‐myelinating Schwann cell nuclei. Apart from numerous pathological nuclei of isolated Schwann cells, multiple profiles of non‐myelinating Schwann cell subunits were apparent in the endoneurium. Schwann cell proliferation in association with first‐hit mutation of the merlin gene might be responsible for the NF2‐associated neuropathy. Sural nerve biopsy showed a progressive neuropathy in the disease. Further, we suggest nonmyelinating Schwann cells are involved in NF2 neuropathy.
The role of nasal CPAP in obstructive sleep apnoea syndrome due to mandibular hypoplasia
Authors: MILLER Stanley D.W. , GLYNN Senan F. , KIELY John L. , McNICHOLAS Walter T.
Published: January 2010

Melnick Needles syndrome (MNS), Treacher Collins syndrome (TCS) and Pierre Robin syndrome (PRS) are congenital abnormalities with characteristic facial appearances that include micrognathia. A 20‐year‐old girl with MNS, a 16‐year‐old boy with TCS and a 12‐year‐old girl with PRS attended the sleep apnoea clinic at our institution at different times. Diagnostic sleep studies were initially performed on all three patients to confirm the diagnosis of obstructive sleep apnoea syndrome (OSAS). They subsequently commenced nasal CPAP (nCPAP) treatment and their progress was followed. A limited sleep study on the patient with MNS demonstrated moderate/severe OSAS with an AHI of 33 events/h. Commencement of nCPAP resulted in symptomatic improvement. Overnight oximetry in the patient with TCS showed repeated desaturation to SpO2 <90%. Subsequent treatment by nCPAP almost completely abolished the desaturation events. Overnight polysomnography in the patient with PRS demonstrated severe OSAS with an AHI of 49 events/h. After 3 years of nCPAP therapy, this patient requested discontinuation of treatment. Subsequent polysomnography without nCPAP revealed an AHI of <5 events/h. The use of nCPAP in the patients with MNS and TCS resulted in effective control of their sleep abnormalities. Mandibular growth and enlargement of the posterior airway space led to resolution of OSAS in the patient with PRS. There is a definite role for nCPAP therapy in patients with congenital micrognathia and OSAS. The use of nCPAP may obviate the need for more invasive corrective surgery for OSAS and is not necessarily a life‐long requirement.
Oxidative stress in non‐small cell lung cancer patients after chemotherapy: Association with treatment response
Authors: GUPTA Abhilasha , SRIVASTAVA Shruti , PRASAD Rajendra , NATU Shanker M. , MITTAL Balraj , NEGI Mahendra P.S. , SRIVASTAVA Anand N.
Published: January 2010

Background and objective:  The aim of this study was to assess the level of oxidative stress after chemotherapy in non‐small cell lung cancer patients, and its association with treatment response and survival.

Methods:  Two hundred and three previously untreated non‐small cell lung cancer patients and 150 healthy subjects were selected for the study. Patients received cisplatin + etoposide, and were followed for up to six cycles, for evaluation of oxidative stress. Blood levels of lipid peroxidation products (LPO), glutathione (GSH) and nitric oxide (NO), and superoxide dismutase (SOD) activity were measured at day 0 and after the third and sixth cycles of chemotherapy. Response and survival were measured at the end of follow up. Survival was estimated by the Kaplan–Meier method using the log–rank test.

Results:  In the patients, pretreatment levels of LPO and NO were low, while GSH and SOD levels were high compared with those after the third and sixth cycles of chemotherapy. Among the 203 patients, there were 51 deaths, 82 non‐responders and 70 responders at the end of the sixth cycle. Overall mean survival was higher among responders than non‐responders (24.6 vs 21.2 weeks, P < 0.01). The hazard ratio was 2.4 (95% CI: 1.3–3.77). Pretreatment levels of oxidative stress were similar among responders and non‐responders (P > 0.05). After the third and sixth cycles of chemotherapy, LPO and NO levels were low (P < 0.05 or P < 0.01) and GSH levels and SOD activity were high (P < 0.05 or P < 0.01) in responders as compared with non‐responders.

Conclusions:  In lung cancer patients, oxidative stress increased and anti‐oxidant enzymes decreased as the disease progressed. Chemotherapy may suppress oxidative stress and decreased anti‐oxidant enzyme activity in responders as compared with non‐responders. These effects may contribute to improved survival among responders.