bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation and transport of oxidized reactive nitrogen, ozone, and secondary organic aerosol in Tokyo
Authors: Kondo Y. , Morino Y. , Fukuda M. , Kanaya Y. , Miyazaki Y. , Takegawa N. , Tanimoto H. , McKenzie R. , Johnston P. , Blake D. R. , Murayama T. , Koike M.
Published: November 2008

Measurements of the major reactive nitrogen species (NOy)i (NOx, peroxyacyl nitrates, HNO3, and particulate nitrate (NO3−)), total reactive nitrogen (NOy), volatile organic compounds, OH and HO2, and organic aerosol were made near the urban center of Tokyo in different seasons of 2003–2004 to study the processes involving oxidized forms of reactive nitrogen and O3. Generally, NOx constituted the dominant fraction of NOy throughout the seasons. The NOx/NOy and HNO3/NOy ratios were lowest and highest, respectively, in summer, owing to the seasonally high OH concentration. The fraction of NOy that remained in the atmosphere after emission (RNOy) decreased with the decrease in the NOx/NOy ratio in summer and fall. It is likely that the median seasonal‐diurnal variations of Ox = O3 + NO2 were controlled by those of the background O3 levels, photochemical O3 formation, and vertical transport. Ox showed large increases during midday under stagnant conditions in mid‐August 2004. Their in situ production rates calculated by a box model were too slow to explain the observed increases. The high Ox was likely due to the accumulation of Ox from previous days in the upper part of the boundary layer (BL) followed by transport down to near the surface by mixing after sunrise. Considering the tight correlation between Ox and secondary organic aerosol (SOA), it is likely that SOA also accumulated during the course of sea‐land breeze circulation in the BL.
Isolation of Peptide Transport System-6 from Brain Endothelial Cells: Therapeutic Effects with Antisense Inhibition in Alzheimer and Stroke Models
Authors: Dogrukol-Ak Dilek , Kumar Vijaya B , Ryerse Jan S , Farr Susan A , Verma Sulekha , Nonaka Naoko , Nakamachi Tomoya , Ohtaki Hirokazu , Niehoff Michael L , Edwards John C , Shioda Seiji , Morley John E , Banks William A
Published: November 2008

By isolating for the first time ever a peptide transporter from the blood—brain barrier (BBB) and developing an antisense that selectively targets the brain-to-blood efflux component, we were able to deliver a therapeutic concentration of the neurotrophic peptide pituitary adenylate cyclase-activating polypeptide (PACAP) 27 to brain in animal models of Alzheimer's and stroke. Efflux pumps at the BBB are major causes of BBB impermeability to peptides. PACAP is neuroprotective in vitro in femtomole amounts, but brain uptake of PACAP27 is limited by an efflux component of peptide transport system-6 (PTS-6). Here, we characterized, isolated, and sequenced this component of PTS-6, identifying it as β-F1 ATPase, and colocalized it with PACAP27 on BBB endothelial cells. Antisenses targeting the BBB inhibited PACAP27 efflux, thus increasing brain uptake of PACAP27. Treatment with antisense +PACAP27 improved cognition in a mouse model of Alzheimer's disease and reduced infarct size after cerebral ischemia. This represents the first isolation from BBB tissue of a peptide transporter and shows that inhibition of peptide efflux pumps is a potential strategy for drug delivery to brain.
Development of antibody fragments for immunotherapy of prion diseases
Authors: Campana Vincenza , Zentilin Lorena , Mirabile Ilaria , Kranjc Agata , Casanova Philippe , Giacca Mauro , Prusiner Stanley B. , Legname Giuseppe , Zurzolo Chiara
Published: November 2008

Prions are infectious proteins responsible for a group of fatal neurodegenerative diseases called TSEs (transmissible spongiform encephalopathies) or prion diseases. In mammals, prions reproduce themselves by recruiting the normal cellular protein PrPC and inducing its conversion into the disease-causing isoform denominated PrPSc. Recently, anti-prion antibodies have been shown to permanently cure prion-infected cells. However, the inability of full-length antibodies and proteins to cross the BBB (blood-brain barrier) hampers their use in the therapy of TSEs in vivo. Alternatively, brain delivery of prion-specific scFv (single-chain variable fragment) by AAV (adeno-associated virus) transfer delays the onset of the disease in infected mice, although protection is not complete. We investigated the anti-prion effects of a recombinant anti-PrP (D18) scFv by direct addition to scrapie-infected cell cultures or by infection with both lentivirus and AAV-transducing vectors. We show that recombinant anti-PrP scFv is able to reduce proteinase K-resistant PrP content in infected cells. In addition, we demonstrate that lentiviruses are more efficient than AAV in gene transfer of the anti-PrP scFv gene and in reducing PrPSc content in infected neuronal cell lines. Finally, we have used a bioinformatic approach to construct a structural model of the D18scFv–PrPC complex. Interestingly, according to the docking results, ArgPrP151 (Arg151 from prion protein) is the key residue for the interactions with D18scFv, anchoring the PrPC to the cavity of the antibody. Taken together, these results indicate that combined passive and active immunotherapy targeting PrP might be promising strategies for therapeutic intervention in prion diseases.
Adiponectin: no longer the lone soul in the fight against insulin resistance?
Authors: Davis Kathryn E. , Scherer Philipp E.
Published: November 2008

Adiponectin is one of the most effective adipokines in the context of correcting obesity-induced insulin resistance. However, adiponectin-deficient animal models show a relatively modest phenotype unless metabolically challenged. This suggests that potent compensatory mechanisms are in place. In this issue of the Biochemical Journal, Wong et al. characterize new members of the CTRPs [C1q-TNFα (tumour necrosis factor α)-related proteins]. They establish that some CTRPs are produced primarily in the stromal vascular fraction of adipose tissue, and that expression of CRTP1, in particular (like adiponectin), is induced by PPARγ (peroxisome-proliferator-activated receptor γ) agonists. Moreover, injection of recombinant CTRP1 displays glucose-lowering effects. These observations suggest that CTRP1 may have partially overlapping functions and, along with other paralogues, may effectively compensate for the chronic loss of adiponectin function.
Effect of acute variations of insulin and glucose on plasma concentrations of asymmetric dimethylarginine in young people with Type 1 diabetes
Authors: Marcovecchio M. Loredana , Widmer Barry , Dunger David B. , Dalton R. Neil
Published: November 2008

ADMA (asymmetric dimethylarginine), an endogenous inhibitor of nitric oxide synthase, is considered a major risk factor for cardiovascular disease and progression of renal disease. In the present study we aim to investigate the effect of acute variations in plasma glucose and insulin on plasma ADMA levels in young people with T1D (Type 1 diabetes). Fifteen young patients (ten males) with T1D, median age 18.3 (13.2–24.4) years, HbA1c (glycated haemoglobin) 9% (6.4–13.6%), underwent an overnight (18:00–08:00 hours) variable insulin infusion for euglycaemia, followed by a hyperinsulinaemic–euglycaemic clamp (08:00–12:00 hours). Blood samples were collected every 15 min for determination of ADMA, SDMA (symmetric dimethylarginine), valine, phenylalanine, arginine, creatinine and glucose. Insulin levels were assessed every 30 min. During the overnight period, glucose levels increased following the evening meal. In response to the protein intake there was a significant increase in ADMA, arginine, valine, phenylalanine and creatinine. For the remaining part of the night, glucose levels progressively decreased reaching 5 mmol/l by 04:00 hours. ADMA and SDMA did not change significantly. During the hyperinsulinaemic clamp, a significant fall in ADMA was observed, from 0.468±0.056 to 0.364±0.050 μmol/l (P<0.001). A significant fall was also found in SDMA, valine, phenylalanine, arginine and the ADMA/SDMA ratio (all P<0.001), but not in creatinine levels. No correlation was found between insulin sensitivity and ADMA. We conclude that acute changes in glycaemia do not significantly affect plasma ADMA levels whereas infusion of insulin significantly reduces ADMA, suggesting an important role for insulin in the regulation of this cardiovascular risk factor.
Epitaxial lateral overgrowth of InP on Si from nano-openings: Theoretical and experimental indication for defect filtering throughout the grown layer
Authors: Olsson F. , Xie M. , Lourdudoss S. , Prieto I. , Postigo P. A.
Published: November 2008

We present a model for the filtration of dislocations inside the seed window in epitaxial lateral overgrowth (ELO). We found that, when the additive effects of image and gliding forces exceed the defect line tension force, filtering can occur even in the openings. The model is applied to ELO of InP on Si where the opening size and the thermal stress arising due to the mask and the grown material are taken into account and analyzed. Further, we have also designed the mask patterns in net structures, where the tilting angles of the openings in the nets are chosen in order to take advantage of the filtering in the openings more effectively, and to minimize new defects due to coalescence in the ELO. Photoluminescence intensities of ELO InP on Si and on InP are compared and found to be in qualitative agreement with the model.
Correlation between the dipole moment induced at the Slater transition state and the optical dielectric constant of Si and Al compounds
Authors: Hirose K. , Kobayashi D. , Suzuki H. , Nohira H.
Published: November 2008

We calculate the difference between the valence charges of the ground state and the Slater transition state for several types of Si compounds and Al compounds. We assume the dipole moment induced by core-hole generation at the Slater transition state to be the product of the valence charge difference and the bond length of the compounds. We find that the calculated dipole moment has a strong linear correlation well with (ε−1)/(ε+2), which is deduced from experimental values of the optical dielectric constant ε.
Pinning synchronization of delayed neural networks
Authors: Zhou Jin , Wu Xiaoqun , Yu Wenwu , Small Michael , Lu Jun-an
Published: November 2008

This paper investigates adaptive pinning synchronization of a general weighted neural network with coupling delay. Unlike recent works on pinning synchronization which proposed the possibility that synchronization can be reached by controlling only a small fraction of neurons, this paper aims to answer the following question: Which neurons should be controlled to synchronize a neural network? By using Schur complement and Lyapunov function methods, it is proved that under a mild topology-based condition, some simple adaptive feedback controllers are sufficient to globally synchronize a general delayed neural network. Moreover, for a concrete neurobiological network consisting of identical Hindmarsh–Rose neurons, a specific pinning control technique is introduced and some numerical examples are presented to verify our theoretical results.
The solvation of NaCl in model water with different hydrogen bond strength
Authors: Gu B. , Zhang F. S. , Wang Z. P. , Zhou H. Y.
Published: November 2008

Based on hybrid water models, we design a series of solvent environments with different hydrogen bond strength and study the solvation of NaCl in them. The microstructures and dynamical behaviors of solvents and ion solutes are presented in detail to trace the correlations between the hydrogen bond strength of water and the solvation mechanism of the ions. In the process of the solvation of NaCl, the balance of the competition between breaking original solvent structures and formation of hydration shells around ions is sensitive to the hydrogen bonding ability of water. The results indicate that NaCl is most ideally dissolved in natural water with the strongest hydration effects around both cations and anions. In solvents with both reduced and enhanced hydrogen bond strength, the ions are more inclined to be in contact or aggregate into clusters of different sizes. These phenomena show that appropriate hydrogen bond strength is crucial for water’s natural dissolving capacity.
Electrical characteristics of metal-oxide-semiconductor capacitors on p-GaAs using atomic layer deposition of ultrathin HfAlO gate dielectric
Authors: Suri Rahul , Lee Bongmook , Lichtenwalner Daniel J. , Biswas Nivedita , Misra Veena
Published: November 2008

Properties of ultrathin HfAlO gate dielectrics on sulfur-passivated p-GaAs were investigated using capacitance-voltage and current-voltage measurement techniques and angle-resolved x-ray photoelectron spectroscopy. By optimizing the individual layer thickness of atomic-layer deposited Al2O3 and HfO2 and the postdeposition anneal (PDA) conditions, a low equivalent oxide thickness of 1.6 nm, low gate leakage of 2.6×10−3 A/cm2 at Vg=Vfb−1 V, and excellent frequency dispersion characteristics were obtained. No interfacial As–O bonding and only a small amount of Ga–O bonding were detected after PDA at 500 °C. These results reveal a good quality dielectric interface on GaAs without an additional interface passivation layer.
Theoretical prediction of HRgCO+ ion (Rg=He, Ne, Ar, Kr, and Xe)
Authors: Jayasekharan T. , Ghanty T. K.
Published: November 2008

Ab initio quantum chemical methods have been employed to investigate the structure, stability, charge redistribution, and harmonic vibrational frequencies of rare gas (Rg=He, Ne, Ar, Kr, and Xe) containing HRgCO+ ion. The Rg atoms are inserted in between the H and C atoms of HCO+ ion and the geometries are optimized for minima as well as transition state using second order Møller–Plesset perturbation theory, density functional theory, and coupled-cluster theory [CCSD(T)] methods. The HRgCO+ ions are found to be metastable and exhibit a linear structure at the minima position and show a nonlinear structure at the transition state. The predicted ion is unstable with respect to the two-body dissociation channel leading to the global minima (HCO++Rg) on the singlet potential surface. The binding energies corresponding to this channel are −406.4, −669.3, −192.3, −115.4, and −52.2 kJ mol−1 for HHeCO+, HNeCO+, HArCO+, HKrCO+, and HXeCO+ ions, respectively, at CCSD(T) method. However, with respect to other two-body dissociation channel, HRg++CO, the ions are found to be stable and have positive energies except for HNeCO+ at the same level of theory. The computed binding energies for this channel are 15.0, 28.8, 29.5, and 29.1 kJ mol−1 for HHeCO+, HArCO+, HKrCO+, and HXeCO+ ions, respectively. Very high positive three-body dissociation energies are found for H+Rg+CO+ and H++Rg+CO dissociation channels. It indicates the existence of a very strong bonding between Rg and H atoms in HRgCO+ ions. The predicted ions dissociate into global minima, HCO++Rg, via a transition state involving H–Rg–C bending mode. The barrier heights for the transition states are 22.7, 10.1, 13.1, and 15.0 kJ mol−1 for He, Ar, Kr, and Xe containing ions, respectively. The computed two-body dissociation energies are comparable to that of the experimentally observed mixed cations such as ArHKr+, ArHXe+, and KrHXe+ in an electron bombardment matrix isolation technique. Thus HRgCO+ cations may also be possible to prepare and characterize similar to the mixed cations (RgHRg′)+ in low temperature matrix isolation technique.
Lineshapes for resonant impulsive stimulated Raman scattering with chirped pump and supercontinuum probe pulses
Authors: Dobryakov A. L. , Ernsting N. P.
Published: November 2008

Molecular vibrational coherence from impulsive stimulated Raman (SR) scattering, as observed by broadband transient absorption spectroscopy, is treated within the well-known third-order perturbation formalism. Shaped femtosecond optical pulses are used for the pump and supercontinuum probe fields. Dephasing is assumed to be homogeneous in the Bloch approximation. A key step requires threefold time integration over response functions and electric fields. For well-separated pulses the triple integral can be solved analytically, resulting in lineshape functions. These allow to describe the SR signal through absorption/emission/dispersion profiles which are associated with the inherent contributions. A clear physical interpretation of the amplitude and phase of the oscillatory signal is thereby obtained, and a direct connection with the vibronic structure of the molecular system is provided. Calculations for model molecular systems illustrate the spectral dependence of the vibrational coherence seen, for example, with perylene in cyclohexane. The nonoscillatory and oscillatory parts of the transient absorption spectra are compared to each other. Observed mode beatings are explained.
Studies on adsorption of mono- and multi-chromophoric hemicyanine dyes on silver nanoparticles by surface-enhanced resonance raman and theoretical calculations
Authors: Biswas Nandita , Thomas Susy , Kapoor Sudhir , Mishra Amaresh , Wategaonkar Sanjay , Mukherjee Tulsi
Published: November 2008

Structural and vibrational properties of mono- and multichromophoric hemicyanine (HC) dyes in solution and adsorbed on silver-coated films have been investigated using optical absorption and resonance Raman scattering techniques, with interpretations aided by theoretical calculations. This is the first report on the Raman spectroscopic studies of multichromophoric HC derivatives. The structure of the monomer, N-propyl-4-(p-N,N-dimethylamino styryl)pyridinium bromide (HC3), and its charged and neutral silver complexes (HC3-Ag) in the ground electronic (S0) state were optimized using density functional calculations with the B3LYP method using the 6-31G* and LANL2DZ basis sets. The ground state structure of N-hexyl-4-(p-N,N-dimethylamino styryl)pyridinium bromide (HC6) and multichromophoric HC dyes were computed using the HF∕6-31G* method. The negligible shift or broadening observed in the electronic absorption and resonance Raman spectra in solution with increasing size of the HC chromophore suggests that the excitations are localized within individual monomer units in bis and tetra chromophores. However, in the tris chromophore, considerable redshift and broadening were observed, indicating a significant electronic interaction between the nonbonded electrons of the N atom and the aromatic π-system that is supported by the calculated excitation energies using the time-dependent density functional theory method. The effect of HC dye concentration on the electronic absorption spectra of the silver-coated film showed significant broadening, which was attributed to the formation of H- and J-aggregates in addition to the formation of a metal-molecule complex. A considerable redshift along various vibrations observed in the surface-enhanced resonance Raman scattering (SERRS) spectra of the HC derivatives indicates that adsorption on the silver surface leads to a considerable interaction of the electron rich moiety of HC derivatives with the silver surface. The enhancement of various in-plane and out-of-plane vibrations, along with slight broadening and redshifts observed in the SERRS spectra, suggests that binding of the HC dyes to the silver surface occurs through the aromatic π-system attached to the electron rich dimethylamino group, with the ring lying almost parallel to the silver surface. Theoretical results have further indicated adsorption via chemisorption for the charged HC3-Ag complexes and by physisorption for the neutral HC3-Ag complexes.
Polarity inversion of N-face GaN by plasma-assisted molecular beam epitaxy
Authors: Wong Man Hoi , Wu Feng , Mates Thomas E. , Speck James S. , Mishra Umesh K.
Published: November 2008

The polarity of GaN grown by plasma-assisted molecular beam epitaxy was inverted from N-face to Ga-face by simultaneously exposing the surface to Mg and activated N fluxes during a growth interruption at a reduced substrate temperature. Growth studies suggested that a MgxNy compound was responsible for inverting the crystal. The change in polarity was verified in situ by reflection high energy electron diffraction via GaN surface reconstructions, and ex situ by convergent beam electron diffraction and KOH etch studies. The surface of the inverted material showed smooth step flow features. Ga-face high electron mobility transistors with good dc and small signal performance were fabricated on the inverted epilayers. A drain-source current of 0.84 A/mm was measured at a gate-source voltage of +1 V. Current-gain cutoff and maximum oscillation frequencies of 22 and 53 GHz, respectively, were measured in these devices. The device performance is similar to that of Ga-face transistors with comparable dimensions.
A Monte Carlo simulation of nanoscale magnetic particle morphology and magnetization
Authors: Di Ziyun , Zhang Dongchen , Chen Xianfeng
Published: November 2008

A model based on Monte Carlo technique is applied to investigating the superparamagnetic magnetite (Fe3O4) colloidal nanocrystal clusters (CNCs) proposed by Ge et al. [Nano Lett. 7, 3203 (2007)]. In other words, the model investigates the following three aspects of CNCS: the morphology of magnetic particles, the formation of field-induced chainlike patterns, and the induced evolution of the magnetization processes. It is shown that the parameters such as diameter, surfactant molecules per unit, and volume concentration of the magnetic fluid are significant factors that enable one to efficiently manipulate the morphology and magnetization process, which eventually leads to the efficient control of the fabrication and multiple applications. The experiment results also evidenced the presence of this self-assembled chain structures.
Softening of the first-order magnetic phase transition and magnetotransport properties of Sm0.55Sr0.45MnO3 manganite
Authors: Egilmez M. , Salman Z. , Mansour A. I. , Chow K. H. , Jung J.
Published: November 2008

We have investigated the changes in the magnetotransport properties of Sm0.55Sr0.45MnO3 manganites caused by the disorder-induced softening of the first-order magnetic phase transition into a second-order one. We analyzed the low field magnetization, magnetotransport, and specific heat in the presence of the first-order and the second-order magnetic phase transitions.
Evaluation of the sensitivity and fading characteristics of an image plate system for x-ray diagnostics
Authors: Meadowcroft A. L. , Bentley C. D. , Stott E. N.
Published: November 2008

Image plates (IPs) are a reusable recording media capable of detecting ionizing radiation, used to diagnose x-ray emission from laser-plasma experiments. Due to their superior performance characteristics in x-ray applications [C. C. Bradford, W. W. Peppler, and J. T. Dobbins III, Med. Phys. 26, 27 (1999) and J. Digit. Imaging. 12, 54 (1999)], the Fuji Biological Analysis System (BAS) IPs are fielded on x-ray diagnostics for the HELEN laser by the Plasma Physics Department at AWE. The sensitivities of the Fuji BAS IPs have been absolutely calibrated for absolute measurements of x-ray intensity in the energy range of 0–100 keV. In addition, the Fuji BAS IP fading as a function of time was investigated. We report on the characterization of three Fuji BAS IP responses to x-rays using a radioactive source, and discrete x-ray line energies generated by the Excalibur soft x-ray facility and the Defense Radiological Standards Centre filter-fluorescer hard x-ray system at AWE.
A metal-wire/quantum-dot composite metamaterial with negative ε and compensated optical loss
Authors: Bratkovsky Alexander , Ponizovskaya Ekaterina , Wang Shih-Yuan , Holmström Petter , Thylén Lars , Fu Ying , Ågren Hans
Published: November 2008

Numerical simulations of a binary mixture of quantum dots exhibiting gain with silver nanorods are performed, showing the feasibility of lossless negative ε operation for realistic material structures and parameters.
Influence of interlayer trapping and detrapping mechanisms on the electrical characterization of hafnium oxide/silicon nitride stacks on silicon
Authors: García H. , Dueñas S. , Castán H. , Gómez A. , Bailón L. , Toledano-Luque M. , del Prado A. , Mártil I. , González-Díaz G.
Published: November 2008

Al / HfO 2 / SiN x : H / n -Si metal-insulator-semiconductor capacitors have been studied by electrical characterization. Films of silicon nitride were directly grown on n-type silicon substrates by electron cyclotron resonance assisted chemical vapor deposition. Silicon nitride thickness was varied from 3 to 6.6 nm. Afterwards, 12 nm thick hafnium oxide films were deposited by the high-pressure sputtering approach. Interface quality was determined by using current-voltage, capacitance-voltage, deep-level transient spectroscopy (DLTS), conductance transients, and flatband voltage transient techniques. Leakage currents followed the Poole–Frenkel emission model in all cases. According to the simultaneous measurement of the high and low frequency capacitance voltage curves, the interface trap density obtained for all the samples is in the 1011 cm−2 eV−1 range. However, a significant increase in this density of about two orders of magnitude was obtained by DLTS for the thinnest silicon nitride interfacial layers. In this work we probe that this increase is an artifact that must be attributed to traps existing at the HfO2/SiNx:H intralayer interface. These traps are more easily charged or discharged as this interface comes near to the substrate, that is, as thinner the SiNx:H interface layer is. The trapping/detrapping mechanism increases the capacitance transient and, in consequence, the DLTS measurements have contributions not only from the insulator/substrate interface but also from the HfO2/SiNx:H intralayer interface.
Containment of fluid samples in the hydrothermal diamond-anvil cell without the use of metal gaskets: Performance and advantages for in situ analysis
Authors: Chou I-Ming , Bassett William A. , Anderson Alan J. , Mayanovic Robert A. , Shang Linbo
Published: November 2008

Metal gaskets (Re, Ir, Inconel, or stainless steel) normally used to contain fluid samples in the hydrothermal diamond-anvil cell (HDAC) are sometimes undesirable due to possible contamination and to gasket deformation at high pressures and temperatures resulting in nonisochoric behavior. Furthermore, in x-ray spectroscopic experiments, metal gaskets may attenuate the incident x-ray beam and emitted fluorescence x-rays, and the interaction of scattered radiation with the gasket may produce fluorescence that interferes with the x-ray spectrum of the sample. New arrangements and procedures were tested for the operation of the HDAC without using the metal gaskets. Distilled, de-ionized water was loaded into the sample chamber, a laser-milled recess 300 μm in diameter and ∼50 μm deep centered in the 1.0 mm face of the lower diamond anvil, and sealed by pressing the top diamond anvil face directly against the lower one without a metal gasket in between. A maximum sample pressure of 202 MPa at 617 °C was maintained for a duration of 10 min without evidence of leakage. A small change in fluid density was observed in one experiment where the sample was held at 266 MPa at 708 °C for 10 min. The gasketless HDAC was also employed in x-ray absorption spectroscopy experiments, where, in addition to the sample chamber in the lower diamond, two grooves were milled at a 90° angle to each other around the sample chamber to minimize the attenuation of incident and fluorescent x rays. With a minimum distance between the sample chamber and the grooves of 80 μm, a pressure of 76 MPa at 500 °C was maintained for 2 h with no change in the original fluid density.
The functional integral with unconditional Wiener measure for anharmonic oscillator
Authors: Boháčik J. , Prešnajder P.
Published: November 2008

In this article we propose the calculation of the unconditional Wiener measure functional integral with a term of the fourth order in the exponent by an alternative method as in the conventional perturbative approach. In contrast to the conventional perturbation theory, we expand into power series the term linear in the integration variable in the exponent. In such a case we can profit from the representation of the integral in question by the parabolic cylinder functions. We show that in such a case the series expansions are uniformly convergent and we find recurrence relations for the Wiener functional integral in the N-dimensional approximation. In continuum limit we find that the generalized Gelfand–Yaglom differential equation with solution yields the desired functional integral (similarly as the standard Gelfand–Yaglom differential equation yields the functional integral for linear harmonic oscillator).
Activated boron and its concentration profiles in heavily doped Si studied by soft x-ray photoelectron spectroscopy and Hall measurements
Authors: Tsutsui Kazuo , Matsuda Toru , Watanabe Masamitsu , Jin Cheng-Guo , Sasaki Yuichiro , Mizuno Bunji , Ikenaga Eiji , Kakushima Kuniyuki , Ahmet Parhat , Maruizumi Takuya , Nohira Hiroshi , Hattori Takeo , Iwai Hiroshi
Published: November 2008

The chemical bonding states of boron (B) in shallow P+/N junctions on Si substrates were studied by soft x-ray photoelectron spectroscopy (SXPES). This study revealed three chemical bonding states of B embedded in bulk Si. The concentration profiles of B were successfully determined by combining SXPES with step-by-step etching of Si substrates. The concentration profiles of B thus determined were in good agreement with those determined by secondary ion mass spectroscopy. The concentration profiles of holes were also determined by combining Hall measurements with the step-by-step etching of Si substrates. The concentration profiles of B having the lowest binding energy were found to agree well with the concentration profiles of holes. Therefore, B with the lowest binding energy can be assigned as activated B and those having the middle and highest binding energies can be attributed to deactivated B having chemical bonding states different from that of activated B.
Large-scale patterning of indium tin oxide electrodes for guided mode extraction from organic light-emitting diodes
Authors: Geyer Ulf , Hauss Julian , Riedel Boris , Gleiss Sebastian , Lemmer Uli , Gerken Martina
Published: November 2008

We describe a cost-efficient and large area scalable production process of organic light-emitting diodes (OLEDs) with photonic crystals (PCs) as extraction elements for guided modes. Using laser interference lithography and physical plasma etching, we texture the indium tin oxide (ITO) electrode layer of an OLED with one- and two-dimensional PC gratings. By optical transmission measurements, the resonant mode of the grating is shown to have a drift of only 0.4% over the 5mm length of the ITO grating. By changing the lattice constant between 300 and 600nm, the OLED emission angle of enhanced light outcoupling is tailored from −24.25° to 37°. At these angles, the TE emission is enhanced up to a factor of 2.14.
Characterization of amorphous and crystalline silicon nanoclusters in ultra thin silica layers
Authors: Thogersen Annett , Mayandi Jeyanthinath , Finstad Terje G. , Olsen Arne , Christensen Jens Sherman , Mitome Masanori , Bando Yoshio
Published: November 2008

The nucleation and structure of silicon nanocrystals formed by different preparation conditions and silicon concentrations (28–70 area %) have been studied using transmission electron microscopy (TEM), energy filtered TEM, and secondary ion mass spectroscopy. The nanocrystals were formed after heat treatment at high temperature of a sputtered 10 nm thick silicon rich oxide on 3 nm SiO2 layer made by rapid thermal oxidation (RTO) of silicon. Nanocrystals precipitate when the excess silicon concentration exceeds 50 area %. Below this percentage amorphous silicon nanoclusters were found. In situ heat treatment of the samples in the TEM showed that the crystallization requires a temperature above 800 °C. The nanocrystals precipitate in a 4 nm band, 5 nm from the Si substrate, and 4 nm from the SiO2 sample surface. The silicon nucleates where the excess Si concentration is the highest. The top surface has less excess Si due to reaction with oxygen from the ambient during annealing. The SiO2-RTO layer is more Si rich due to Si diffusion from the SiO2–Si layer into RTO. Twinning and stacking faults were found in nanocrystals with 4–10 nm in diameter. These types of defects may have large effects on the usability of the material in electronic devices. Both single and double twin boundaries have been found in the nanocrystals by high resolution TEM. Image simulations were carried out in order to obtain more information about the defects and nanocrystals. The stacking faults are extrinsic and located in the twin boundaries.
Defect passivation and homogenization of amorphous oxide thin-film transistor by wet O2 annealing
Authors: Nomura Kenji , Kamiya Toshio , Ohta Hiromichi , Hirano Masahiro , Hosono Hideo
Published: November 2008

Roles of H2O addition to an annealing atmosphere were investigated for amorphous In–Ga–Zn–O thin-film transistors fabricated at room temperature. Although dry O2 annealing improved saturation mobility (μsat) and subthreshold voltage swings (S), wet O2 annealing further improved them to μsat∼12cm2(Vs)−1 and S<0.12Vdecade−1 along with improvement of their uniformity. Desorption of OH-related species caused conductivity increase during thermal annealing at <310°C. Zn–O components started to desorb at ∼300°C for the unannealed and the dry O2 annealed films, while these were suppressed remarkably by the wet O2 annealing.
Effects of background oxygen pressure on dielectric and ferroelectric properties of epitaxial (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.10,Sb0.06)O3 thin films on SrTiO3
Authors: Abazari M. , Akdoğan E. K. , Safari A.
Published: November 2008

Oxygen partial pressure (PO2) in pulsed laser deposition significantly influences the composition, microstructure, and electrical properties of epitaxial misfit strain-relieved 450nm ⟨001⟩ oriented epitaxial (K0.44,Na0.52,Li0.04)(Nb0.84,Ta0.10,Sb0.06)O3 thin films on SrRuO3 coated SrTiO3. Films deposited at 400mTorr exhibit high remnant and saturated polarization of 7.5 and 16.5μC∕cm2, respectively, which is ∼100% increase over the ones grown at 100mTorr. The dielectric constant linearly increases from 220 to 450 with increasing PO2. The observed changes in surface morphology of the films and their properties are shown to be due to the suppression of volatile A-site cation loss.
Observation of long range correlation dynamics in BaTiO3 near TC by photon correlation spectroscopy
Authors: Yan Rui , Guo Zhi , Tai Renzhong , Xu Hongjie , Zhao Xiangyong , Lin Di , Li Xiaobing , Luo Haosu
Published: November 2008

Long range correlation dynamics of polarization clusters in BaTiO3 have been observed directly near the Curie temperature (TC) by photon correlation spectroscopy. A correlation length on the order of 200nm was found to be dynamic near TC with a characteristic relaxation time of several microseconds. This relaxation time decreased with an increase in temperature, but exhibited an anomaly at TC, indicating the dominating contribution to the dielectric permittivity by these polarization clusters near TC.
High performance germanium N+∕P and P+∕N junction diodes formed at low Temperature (⩽380°C) using metal-induced dopant activation
Authors: Park Jin-Hong , Kuzum Duygu , Tada Munehiro , Saraswat Krishna C.
Published: November 2008

We demonstrate high performance Ge N+∕P and P+∕N junction diodes at sub-380°C. Very low resistivity (2.2×10−4Ωcm) and shallow (92nm) junction with high degree of dopant activation are achieved especially in N+∕P junction formed at 360°C on Ge epitaxially grown on Si using complementary metal-oxide semiconductor process compatible-metal (Co) induced dopant activation technique. Excellent diode characteristics having ∼2×104 on/off ratio and high forward current density (221A∕cm2 for N+∕P and 135A∕cm2 for P+∕N at ∣VF∣=2V) are obtained in N+∕P and P+∕N junction diodes fabricated at 380°C on bulk Ge with a surface passivated layer [GeO2+low temperature chemical vopor deposition SiO2 (LTO)] isolation.
Improvement of magnetic properties of an Fe-6.5 wt. % Si alloy by directional recrystallization
Authors: Zhang Z. W. , Chen G. , Bei H. , Ye F. , Chen G. L. , Liu C. T.
Published: November 2008

We report that magnetic properties of an Fe-6.5 wt. % Si alloy can be improved through texture control by using directional recrystallization. Columnar grain structures with column sizes of ∼0.38×1.2 mm2 were developed during directional recrystallization. It was found that there are low energy boundaries between columns and main textures of the specimen were {110}⟨111⟩ and {111}⟨110⟩. As a result, the coercivity of a directionally recrystallized specimen is reduced by a factor of 5 when measured along 60° away from the growth direction, as compared to a specimen consisting of ∼77 μm equiaxed grains.
ATR kinase is required for global genomic nucleotide excision repair exclusively during S phase in human cells
Authors: Auclair Yannick , Rouget Raphael , Affar El Bachir , Drobetsky Elliot A.
Published: November 2008

Global-genomic nucleotide excision repair (GG-NER) is the only pathway available to humans for removal, from the genome overall, of highly genotoxic helix-distorting DNA adducts generated by many environmental mutagens and certain chemotherapeutic agents, e.g., UV-induced 6–4 photoproducts (6–4PPs) and cyclobutane pyrimidine dimers (CPDs). The ataxia telangiectasia and rad-3-related kinase (ATR) is rapidly activated in response to UV-induced replication stress and proceeds to phosphorylate a plethora of downstream effectors that modulate primarily cell cycle checkpoints but also apoptosis and DNA repair. To investigate whether this critical kinase might participate in the regulation of GG-NER, we developed a novel flow cytometry-based DNA repair assay that allows precise evaluation of GG-NER kinetics as a function of cell cycle. Remarkably, inhibition of ATR signaling in primary human lung fibroblasts by treatment with caffeine, or with siRNA specifically targeting ATR, resulted in total inhibition of 6–4PP removal during S phase, whereas cells repaired normally during either G

0
/G
1

or G

2

/M. Similarly striking S-phase-specific defects in GG-NER of both 6–4PPs and CPDs were documented in ATR-deficient Seckel syndrome skin fibroblasts. Finally, among six diverse model human tumor strains investigated, three manifested complete abrogation of 6–4PP repair exclusively in S-phase populations. Our data reveal a highly novel role for ATR in the regulation of GG-NER uniquely during S phase of the cell cycle, and indicate that many human cancers may be characterized by a defect in this regulation.
Horizontal gene transfer of the algal nuclear gene
psbO
to the photosynthetic sea slug
Elysia chlorotica
Authors: Rumpho Mary E. , Worful Jared M. , Lee Jungho , Kannan Krishna , Tyler Mary S. , Bhattacharya Debashish , Moustafa Ahmed , Manhart James R.
Published: November 2008

The sea slug
Elysia chlorotica
acquires plastids by ingestion of its algal food source
Vaucheria litorea
. Organelles are sequestered in the mollusc's digestive epithelium, where they photosynthesize for months in the absence of algal nucleocytoplasm. This is perplexing because plastid metabolism depends on the nuclear genome for >90% of the needed proteins. Two possible explanations for the persistence of photosynthesis in the sea slug are (
i
) the ability of
V. litorea
plastids to retain genetic autonomy and/or (
ii
) more likely, the mollusc provides the essential plastid proteins. Under the latter scenario, genes supporting photosynthesis have been acquired by the animal via horizontal gene transfer and the encoded proteins are retargeted to the plastid. We sequenced the plastid genome and confirmed that it lacks the full complement of genes required for photosynthesis. In support of the second scenario, we demonstrated that a nuclear gene of oxygenic photosynthesis,
psbO
, is expressed in the sea slug and has integrated into the germline. The source of
psbO
in the sea slug is
V. litorea
because this sequence is identical from the predator and prey genomes. Evidence that the transferred gene has integrated into sea slug nuclear DNA comes from the finding of a highly diverged
psbO
3′ flanking sequence in the algal and mollusc nuclear homologues and gene absence from the mitochondrial genome of
E. chlorotica
. We demonstrate that foreign organelle retention generates metabolic novelty (“green animals”) and is explained by anastomosis of distinct branches of the tree of life driven by predation and horizontal gene transfer.
BCR-ABL-transformed GMP as myeloid leukemic stem cells
Authors: Minami Yosuke , Stuart Scott A. , Ikawa Tomokatsu , Jiang Yong , Banno Asoka , Hunton Irina C. , Young Dennis J. , Naoe Tomoki , Murre Cornelis , Jamieson Catriona H. M. , Wang Jean Y. J.
Published: November 2008

During blast crisis of chronic myelogenous leukemia (CML), abnormal granulocyte macrophage progenitors (GMP) with nuclear β-catenin acquire self-renewal potential and may function as leukemic stem cells (Jamieson
et al. N Engl J Med
, 2004). To develop a mouse model for CML-initiating GMP, we expressed p210
BCR-ABL
in an established line of
E2A
-knockout mouse BM cells that retain pluripotency in ex vivo culture. Expression of BCR-ABL in these cells reproducibly stimulated myeloid expansion in culture and generated leukemia-initiating cells specifically in the GMP compartment. The leukemogenic GMP displayed higher levels of β-catenin activity than either the nontransformed GMP or the transformed nonGMP, both in culture and in transplanted mouse BM. Although
E2A
-deficiency may have contributed to the formation of leukemogenic GMP, restoration of E2A-function did not reverse BCR-ABL-induced transformation. These results provide further evidence that BCR-ABL-transformed GMP with abnormal β-catenin activity can function as leukemic stem cells.
Brain mast cells link the immune system to anxiety-like behavior
Authors: Nautiyal Katherine M. , Ribeiro Ana C. , Pfaff Donald W. , Silver Rae
Published: November 2008

Mast cells are resident in the brain and contain numerous mediators, including neurotransmitters, cytokines, and chemokines, that are released in response to a variety of natural and pharmacological triggers. The number of mast cells in the brain fluctuates with stress and various behavioral and endocrine states. These properties suggest that mast cells are poised to influence neural systems underlying behavior. Using genetic and pharmacological loss-of-function models we performed a behavioral screen for arousal responses including emotionality, locomotor, and sensory components. We found that mast cell deficient Kit
W−sh/W−sh
(sash
−/−
) mice had a greater anxiety-like phenotype than WT and heterozygote littermate control animals in the open field arena and elevated plus maze. Second, we show that blockade of brain, but not peripheral, mast cell activation increased anxiety-like behavior. Taken together, the data implicate brain mast cells in the modulation of anxiety-like behavior and provide evidence for the behavioral importance of neuroimmune links.
Protein evolution with an expanded genetic code
Authors: Liu Chang C. , Mack Antha V. , Tsao Meng-Lin , Mills Jeremy H. , Lee Hyun Soo , Choe Hyeryun , Farzan Michael , Schultz Peter G. , Smider Vaughn V.
Published: November 2008

We have devised a phage display system in which an expanded genetic code is available for directed evolution. This system allows selection to yield proteins containing unnatural amino acids should such sequences functionally outperform ones containing only the 20 canonical amino acids. We have optimized this system for use with several unnatural amino acids and provide a demonstration of its utility through the selection of anti-gp120 antibodies. One such phage-displayed antibody, selected from a naïve germline scFv antibody library in which six residues in V
H
CDR3 were randomized, contains sulfotyrosine and binds gp120 more effectively than a similarly displayed known sulfated antibody isolated from human serum. These experiments suggest that an expanded “synthetic” genetic code can confer a selective advantage in the directed evolution of proteins with specific properties.
Discursive illusions in the American National Strategy for Combating Terrorism
Authors: Bhatia Aditi
Published: November 2008

Social realities are often negotiated and determined by elite groups of society, including political and religious leaders, the mass media, and even professional experts, who give meaning to complex, multifaceted constructs such as terrorism consistent with their individual socio-political agendas. The Bush Administrations National Strategy for Combating Terrorism (NSCT) (2003) defines what we the public and media understand by the term terrorism; who are terrorists; what constitutes terrorism; how we can fight terrorism, etc. In order to convince audiences that the version of reality that the NSCT is representing is the objective truth, particular themes such as the construction of religion, Weapons of Mass Destruction (WMDs), orientalism, and attack vs. self-defence, typically realised through the use of rhetorical resources such as category work, appeals to historicity, negative other-presentation, and the use of metaphor, are utilised. Metaphors are used to construct new and alternate realities. They allow a subjective conceptualisation of reality to appear more convincing through the invocation of emotions and ideologies. Drawing on a detailed analysis of NSCT, the paper investigates how metaphors are combined with other features of language and rhetoric to achieve the themes mentioned above enabling the discourse of illusion to take effect.
Security for All? Politics, Economy & the Growth of Private Security in Swaziland
Authors: Simelane Hamilton
                      Sipho
Published: November 2008

Like many other African countries, Swaziland has in recent years experienced a rapid growth of various private security initiatives. In urban areas, security privatisation manifests itself in the form of a mushrooming of formal private security companies, while in rural areas, where the majority of people live, informal Community Police groups operating outside the control and recognition of the public police provide protection against crime. This article argues that the growth of private security initiatives in Swaziland cannot be understood only with reference to the ‘weak’ African state, but must also be analysed in the context of the country's unequal political economy and the utilisation of public security forces for regime security.
Biological Codes and Topological Causation
Authors: Jantzen Benjamin , Danks David
Published: November 2008

Various causal details of the genetic process of translation have been singled out to account for its privileged status as a ‘code’. We explicate the biological uses of coding talk by characterizing a class of special causal processes in which topological properties are the causally relevant ones. This class contains both the process of translation and communication theoretic coding processes as special cases. We propose a formalism in terms of graphs for expressing our theory of biological codes and discuss its utility in understanding biological systems.