bluuebunny/crossref_metadata_2025 huggingface dataset:
Initial stages of GaP heteroepitaxy on nanoscopically roughened (001)Si
Authors: Liu X. , Kim I. K. , Aspnes D. E.
Published: August 2007

The authors report real-time spectroscopic-polarimetric determinations of the initial phase of GaP heteroepitaxy by organometallic chemical vapor deposition on nanoscopically roughened (NR) (001)Si substrates, where polarimetry measurements are also used to quantify roughness. The authors compare the results with analogous data for GaP homoepitaxy and the initial phase of GaP heteroepitaxy on (001)GaAs. The large density of nucleation sites on NRSi significantly improves film continuity relative to nonroughened vicinal (001)Si substrates, but conditions that are typically used to grow GaP on (001)III-V surfaces generate metallic Ga, indicating that NRSi is more efficient at decomposing trimethylgallium than either GaP or GaAs.
Growth of carbon nanotubes with resist-assisted patterning process
Authors: Park Kyu Chang , Ryu Je Hwang , Kim Ki Seo , Yu Yi Yin , Jang Jin
Published: August 2007

The authors developed a growth method for carbon nanotubes (CNTs) by using a resist-assisted patterning process. The CNTs can be grown directly on the patterned catalyst surface without a diffusion barrier. The growth-site patterns were fabricated on a nickel/silicon (Ni∕Si) substrate by a conventional lithography method using a photopatternable resist. The growth mechanism of the CNTs without diffusion barrier was confirmed by Raman spectroscopy and transmission-electron microscope measurement. The carbon-network formation during forming the process is a key parameter for CNT growth. The technique will be applicable to a low-cost fabrication process of electron-emitter arrays.
Role of subsurface defects in metal-ZnO(0001¯) Schottky barrier formation
Authors: Mosbacker H. L. , El Hage S. , Gonzalez M. , Ringel S. A. , Hetzer M. , Look D. C. , Cantwell G. , Zhang J. , Song J. J. , Brillson L. J.
Published: August 2007

The authors fabricated diodes of Au, Al, Ni, Pt, Pd, Mo, Ta, and Ir on single crystal ZnO(0001¯) surfaces from different vendors and measured their Schottky barriers, idealities, and reverse currents on as-received and remote oxygen (20% O2∕80%He) plasma-treated surfaces. Using low temperature nanoscale depth-resolved cathodoluminescence spectroscopy (DRCLS) under the metal, the authors identified the presence of defect transitions at 2.1, 2.5, and 3.0eV that change dramatically depending on the process steps and choice of metal. I-V measurements exhibited transitions from Ohmic to Schottky and lower idealities for Pt, Au, Ir, and Pd with plasma treatment. ZnO with low defect densities yield lower idealities and reverse currents. Deep level optical and transient spectroscopies correlated bulk and surface defects, showing deep levels at 2.54 and 0.53eV, while DRCLS shows that these densities can increase by >100 times at the surface. The magnitude of the metal’s influence correlates directly to the relative defect concentrations near the surface and in the bulk. These results show that metals can induce defect states at the metal-semiconductor interface and impact device performance.
Highly selective isotropic dry etch based nanofabrication
Authors: Hussain Muhammad Mustafa , Gebara Gabriel , Sassman Barry , Lanee Sidi , Larson Larry
Published: August 2007

Metallic nanowires have significant importance in microelectronic circuits [N. A. Melosh et al., Science 300, 112 (2003)], memory cells, optics [X. Wu et al., Nature (London) 430, 61 (2004)], liquid crystal displays [C. Lapointe et al., Science 303, 652 (2004)], and sensors [R. C. Walter et al., Surf. Interface Anal. 34, 409 (2002)]. There are various methods for fabricating patterned nanostructures such as nanowires, but high cost, low throughput, and uniformity are still their major issues [M. Hernandez-Velez, Thin Solid Films 495, 51 (2006)]. Therefore, a simple nanofabrication technique that uses existing microfabrication tool sets and methods to fabricate nanostructures such as nanowires with accuracy and flexibility is required. Here, the authors show use of a historically well-known method [Z. Yu et al., J. Vac. Sci. Technol. B 21, 2089 (2003)] based on overetch triggered undercutting to fabricate thin film nanowires on a silicon wafer. For the first time, batch-fabricated metallic nanowire—titanium nitride (TiN)—on 200mm silicon wafers using highly selective, timed, isotropic dry etch is being reported. Use of conventional microfabrication in the author’s demonstrated technique indicates the simplicity and economy of fabricating nanowires.
Observation of fringelike electron-emission pattern in field emission from Pt field emitter fabricated by electron-beam-induced deposition
Authors: Murakami K. , Wakaya F. , Takai M.
Published: August 2007

A Pt field emitter with two adjacent emission sites of a gap size of less than 10nm was fabricated using electron-beam-induced deposition followed by annealing. The emission patterns of electrons from the two adjacent sites were observed by field-emission microscopy at room temperature and 100K. The striped emission patterns, corresponding to the interference fringes by electron waves in field emission, were observed for the first time. The fringelike electron-emission patterns in this experiment were found to be in a good agreement with those of the Young’s interference from the two emission sites.
Fabrication of complementary metal-oxide-semiconductor compatible semiconducting yttrium barium copper oxide uncooled infrared microbolometer arrays
Authors: Kumar Sandeep , Chitteboyina Murali M. , Butler Donald P.
Published: August 2007

This article presents the fabrication of complementary metal-oxide-semiconductor (CMOS) compatible micromachined semiconducting yttrium barium copper oxide (YBCO) microbolometer arrays. YBCO in the semiconducting phase at room temperature is used as an uncooled IR microbolometer. It possesses a relatively high temperature coefficient of resistance, a relatively low 1∕f noise, and the ease of fabrication by rf magnetron sputtering at ambient temperature. In this work, YBCO microbolometers are integrated with CMOS readout circuits using capacitive transimpedance amplifier and constant current buffered direct injection design techniques in AMI 1.5μm double-poly-double-metal n-well 2.5V CMOS technology. The self-supporting micromachined YBCO exhibits low thermal mass and hence provides low thermal time constant for the same degree of thermal isolation. The thermal isolation of the microbolometers is varied by designing two different electrode arm geometries. The first geometry is designed to obtain a relatively fast 200Hz frame rate while maintaining a moderate detectivity that provides the potential for a faster frame rate imaging that is advantageous in a variety of applications where the camera or objects in the scene are in motion, and the second arm geometry is designed to achieve a traditional 30Hz frame rate with high detectivity microbolometers.
Microstructuring by microcontact printing and selective surface dewetting
Authors: Benor Amare , Wagner Veit , Knipp Dietmar
Published: August 2007

A universal microstructuring approach was developed for patterning surfaces by microcontact printing in combination with selective surface dewetting. Self-assembled monolayers such as octadecyltrichlorosilane [CH3(CH2)17SiCl3] were printed on glass or silicon substrates by microcontact printing. The octadecyltrichlorosilane-coated regions became hydrophobic, whereas the uncoated regions remained hydrophilic. Such functionalized substrates facilitate selective wetting/dewetting of surfaces by polymers or resists. Resists such as poly(methyl methacrylate) were selectively deposited on the hydrophilic regions of the substrate, whereas the hydrophobic regions remained uncoated. The approach allows for patterning of resist on substrates without using photolithography. In this study, the resist was used to lift off metallic microstructures such as microcoils for radio-frequency identification tags and source-drain electrodes for organic field-effect transistors.
High aspect ratio Bosch etching of sub-0.25μm trenches for hyperintegration applications
Authors: Wang Xiaodong , Zeng Wanxue , Lu Guoping , Russo Onofrio L. , Eisenbraun Eric
Published: August 2007

The ability to predict and optimize the effects of the process parameters during silicon dry etching is vital for the fabrication of emerging hyperintegration technologies, as well as many microelectromechanical systems and integrated circuit devices. This article outlines the establishment of reactive ion etching protocols for fabrication of high aspect ratio trenches with minimum scalloping and undercut, employing the Bosch process. High aspect ratio submicron trench array patterns were transferred into silicon substrates using a Unaxis Versalock deep reactive ion etch tool equipped with a time multiplexed plasma etch/passivation cycle scheme which uses an inductively coupled plasma etcher. Through careful optimization of Bosch etch process conditions, successful etching of high aspect ratio (20:1) 170nm trench features was achieved.
Fabrication and characterization of Si nanocrystals in SiC matrix produced by magnetron cosputtering
Authors: Song Dengyuan , Cho Eun-Chel , Conibeer Gavin , Cho Young-Hyun , Huang Yidan , Huang Shujuan , Flynn Chris , Green Martin A.
Published: August 2007

Si-rich amorphous silicon carbide thin films were prepared by magnetron cosputtering and were subsequently annealed to form Si nanocrystals embedded in a SiC matrix. A sputter target consisted of a patterned Si wafer on top of a carbon target. The ratio of carbon to silicon in deposited films was adjusted by means of a different silicon wafer open area. X-ray photoelectron spectroscopy spectra show that various compositions were obtained by changing the sputtered area ratio of carbon to silicon target. Analysis of atomic force microscopy shows that surface roughness increases significantly after annealing. Transmission electron microscopy reveals that Si nanocrystals do not form at temperatures less than 800°C, while they are clearly established, with sizes ranging from 3to7nm, as the temperature is at 1100°C. IR spectra show that increase in annealing temperature for the Si-rich Si1−xCx (x<0.5) films favors the formation of Si–C bonds and increase of the short-range order. Optical studies show a blueshift of the optical absorption edge in transmission spectra and increase in the optical band gap with increasing annealing temperature. Optical band gaps upon annealing were correlated with increasing Si–C bond density and ordering in the SiC matrix due to structural relaxation of the films.
Analytic description of scanning capacitance microscopy
Authors: Murray Hugues , Germanicus Rosine , Doukkali Aziz , Martin Patrick , Domenges Bernadette , Descamps Philippe
Published: August 2007

Scanning capacitance microscopy (SCM) is a doping profile extraction using a nanometric probe as a gate of a metal-oxide-semiconductor (MOS) structure and measuring the differential capacitance. Thanks to the complete MOS equations, the authors propose in this article a description of the differential capacitance calculation. This analytic presentation is based on the solution of the Poisson-Boltzmann equation in the unidimensional mode in silicon and a decomposition of the probe in elementary rings giving capacitance from the surface probe and silicon. As [dC(Vg)∕dVg]α(dΨs∕dVg), this presentation yields to the importance of the surface band bending Ψs at the oxide-semiconductor interface. The dC(Vg)∕dVg calculation shows that the contact of the probe with the sample has its main contribution over a few nanometers. Results are discussed to obtain a calibration of a SCM probe available in a large range of doping and voltage and to assess the dC(Vg)∕dVg signal after erosion of the probe by successive scans.
Precise patterning of SiO2-based glass by low-temperature nanoimprint lithography assisted by UV irradiation on both faces using Glasia® as a precursor
Authors: Okinaka Motoki , Tsushima Hiroshi , Ichinose Yoshifumi , Watanabe Emi , Yanagisawa Keiichi , Tsukagoshi Kazuhito , Aoyagi Yoshinobu
Published: August 2007

Precise patterning of glass has been achieved by low-temperature nanoimprint lithography using Glasia® as a precursor. The main constitute of the Glasia® is polysilane polymer. The polysilane with a simple structure enables the rapid patterning of line and space structures ranging from 50nmto25μm and air-hole structures with a high aspect ratio of 5 at temperatures lower than 80°C. UV irradiation on both faces transforms the polysilane into SiO2-based glass and improves the properties of glass through photo-oxidation. The patterned structure baked at 250°C shows no shrinkage. It is suggested that the incorporation of the oxygen into the patterned film during heat treatment minimizes the shrink due to the evaporation of organic side chains. The patterned SiO2-based glass material withstands ultrasonication in acetone, and has about twice the Vickers hardness of poly(methylmethacrylate) (PMMA).
COSMOLOGICAL SYMMETRY BREAKING, PSEUDO-SCALE INVARIANCE, DARK ENERGY AND THE STANDARD MODEL
Authors: JAIN PANKAJ , MITRA SUBHADIP
Published: August 2007

The energy density of the universe today may be dominated by the vacuum energy of a slowly rolling scalar field. Making a quantum expansion around such a time-dependent solution breaks fundamental symmetries of quantum field theory. We call this mechanism cosmological symmetry breaking and argue that it is different from the standard phenomenon of spontaneous symmetry breaking. We illustrate this with a toy scalar field theory, whose action displays a U(1) symmetry. We identify a symmetry, called pseudo-scale invariance, which sets the cosmological constant exactly equal to zero, both in classical and quantum theories. This symmetry is also broken cosmologically and leads to a nonzero vacuum or dark energy. The slow-roll condition along with the observed value of dark energy leads to a value of the background scalar field of the order of Planck mass. We also consider a U(1) gauge symmetry model. Cosmological symmetry breaking, in this case, leads to a nonzero mass for the vector field. We also show that a cosmologically broken pseudo-scale invariance can generate a wide range of masses.
A NOTE ON KLEIN–GORDON EQUATION IN A GENERALIZED KALUZA–KLEIN MONOPOLE BACKGROUND
Authors: RADU EUGEN , VISINESCU MIHAI
Published: August 2007

We investigate solutions to the Klein–Gordon equation in a class of five-dimensional geometries presenting the same symmetries and asymptotic structure as the Gross–Perry–Sorkin monopole solution. Apart from globally regular metrics, we consider also squashed Kaluza–Klein black holes backgrounds.
PLASMA INDUCED FERMION SPIN–FLIP CONVERSION fL → fR + γ
Authors: KUZNETSOV A. V. , MIKHEEV N. V.
Published: August 2007

The fermion spin–flip conversion fL → fR + γ is considered, caused by the difference of the additional energies of the electroweak origin, acquired by left- and right-handed fermions (neutrino, electron) in medium. An accurate analysis of the fermion and photon dispersion in medium is performed. It is shown that the threshold arises in the process, caused by the photon (plasmon) effective mass. This threshold leaves no room for the so-called "spin light of neutrino" and "spin light of electron" in the real astrophysical situations.
MODELING THE MULTIWAVELENGTH SPECTRA AND VARIABILITY OF 3C 66A IN 2003–2004
Authors: JOSHI M. , BÖTTCHER M.
Published: August 2007

The BL Lac object 3C 66A was the target of an intensive multiwavelength monitoring campaign organized in 2003–2004. During the campaign, its spectral energy distribution (SED) was measured and flux measurements from radio to X-ray frequencies as well as upper limits in the very high energy (VHE) γ-ray regime were obtained. Here, we reproduce the SED and optical spectral variability pattern observed during our multiwavelength campaign using a time-dependent leptonic jet model. Our model could successfully simulate the observed SED and optical light curves and predict an intrinsic cutoff value for the VHE γ-ray emission at ~4 GeV implying the effect of the optical depth due to the intergalactic infrared background radiation (IIBR) to be negligible. Also, the contribution of external Comptonization (EIC), due to the presence of a broad-line region (BLR), in the emission of γ-ray photons could be significant early-on when the emission region is very close to the central engine but as it travels farther out, the production mechanism of hard X-ray and γ-ray photons becomes dominated by synchrotron self-Compton mechanism (SSC).
Siberian trap magmatism on the New Siberian Islands: constraints for Arctic Mesozoic plate tectonic reconstructions
Authors: Kuzmichev Alexander B. , Pease Victoria L.
Published: August 2007

It is widely held that a large composite terrane including the East Siberian shelf, Northern Chukotka and Arctic Alaska moved to its current location from the other side of the Mesozoic ocean in the course of the Amerasia basin opening. The western boundary of this terrane is critical for tectonic models of the Mesozoic Arctic. Consequently, the New Siberian Islands, which lie in the centre of this critical region, should help to define the position of this boundary. We have studied subvolcanic gabbroic intrusions on Bel'kov Island, the westernmost island in the New Siberian Archipelago. Their age is 252 ± 2 Ma (U–Pb zircon, secondary ion microprobe technique) and they represent mantle-derived tholeiitic magma modified by continental crust contamination. Their age and petrographic and geochemical features are identical to those of the Siberian traps, suggesting that in Early Mesozoic time the western New Siberian Islands were adjacent to northern Siberia (modern coordinates). This indicates that the large composite terrane that includes the western New Siberian Islands is not exotic to Siberia as is currently implied in some Arctic Mesozoic tectonic reconstructions.
A composite stratigraphy for the Neoproterozoic Huqf Supergroup of Oman: integrating new litho-, chemo- and chronostratigraphic data of the Mirbat area, southern Oman
Authors: RIEU RUBEN , ALLEN PHILIP A. , COZZI ANDREA , KOSLER JAN , BUSSY FRANCOIS
Published: August 2007

The Huqf Supergroup in Oman contains an exceptionally well-preserved and complete sedimentary record of the Middle to Late Neoproterozoic Era. Outcrops of the Huqf Supergroup in northern and central Oman are now well documented, but their correlation with a key succession in the Mirbat area of southern Oman, containing a sedimentary record of two Neoproterozoic glaciations, is poorly understood. Integration of lithostratigraphic, chemostratigraphic and new U–Pb detrital zircon data suggests that the Mirbat Group is best placed within the Cryogenian (
c
. 850–635 Ma) part of the Huqf Supergroup. The
c
. 1 km thick marine deposits of the Arkahawl and Marsham Formations of the Mirbat Group are thought to represent a stratigraphic interval between older Cryogenian and younger Cryogenian glaciations that is not preserved elsewhere in Oman. The bulk of detrital zircons in the Huqf Supergroup originate from Neoproterozoic parent rocks. However, older Mesoproterozoic, Palaeoproterozoic and even Archaean zircons can be recognized in the detrital population from the upper Mahara Group (Fiq Formation) and Nafun Group, suggesting the tapping of exotic sources, probably from the Arabian–Nubian Shield.
The movement history and fault rock evolution of a reactivated crustal-scale strike-slip fault: the Walls Boundary Fault Zone, Shetland
Authors: Watts L.M. , Holdsworth R.E. , Sleight J.A. , Strachan R.A. , Smith S.A.F.
Published: August 2007

The Walls Boundary Fault Zone is a crustal-scale strike-slip fault that cuts Precambrian–Caledonian basement terranes in Shetland and has been interpreted as the northern continuation of the Great Glen Fault Zone in Scotland. This paper presents the first detailed account of the kinematic history and fault rock assemblages associated with the onshore evolution of the Walls Boundary Fault Zone. These observations suggest that it initiated as a major late Caledonian (Silurian–Devonian) sinistral strike-slip fault associated with the successive development of mylonites and cataclasites. These fault rocks are preserved only locally, and elsewhere are obscured by the effects of later brittle overprinting and dismemberment of the fault zone during dextral strike-slip reactivation, probably during late Carboniferous inversion of the Orcadian Basin. This led to the development of extensive cataclasite and fault gouge assemblages, which are widely preserved along the Walls Boundary Fault. Narrow zones of post-Triassic dip-slip, and finally sinistral strike-slip, reactivation are localized within earlier-formed gouge-filled fault cores. There are some similarities to the kinematic history of the Great Glen Fault Zone, most notably the recognition of late Caledonian sinistral shear and post-Devonian dextral reactivation, but the post-Triassic reactivation histories appear to differ significantly.
Linking crustal reworking to terrane accretion
Authors: Clark C. , Hand M. , Kelsey D.E. , Goscombe B.
Published: August 2007

The Strangways Metamorphic Complex in central Australia is a key terrane in models for the evolution of the Australian continent. The Arunta Complex preserves a long-lived (
c
. 1700–320 Ma) record of crustal reworking, the drivers of which are the subject of considerable debate. Pressure–temperature data and
in situ
monazite geochronology constrain the reworking to be coincident with the
c
.1645 Ma Liebig Orogeny. This suggests that reworking in the Strangways Metamorphic Complex is related to terrane accretion rather than other factors such as anomalous enrichment in high-heat-producing elements or within-plate processes.
Understanding K-feldspar
40
Ar/
39
Ar data: reconciling models, methods and microtextures
Authors: McLaren Sandra , Dunlap W.James , Powell Roger
Published: August 2007

Several descriptions of argon diffusion in K-feldspar have been developed, including the quantitative multiple-diffusion-domain (MDD) and multipath models and the qualitative ‘recrystallization’ model. These models remain contentious and the natural range in behaviour remains poorly understood. Feldspars from the Klokken syenite intrusion show a systematic relationship between
40
Ar/
39
Ar age and microtexture suggesting that the loss of argon from different feldspars operates via different mechanisms such that the existing models represent only end-member scenarios. The MDD model can yield reliable thermal history information only for feldspars with pristine microtexture, with this model best viewed as a cipher for the real (but unknown) domain structure in such samples.
Neoproterozoic glaciation in the Earth System
Authors: Fairchild Ian J. , Kennedy Martin J.
Published: August 2007

The Neoproterozoic contains severe glacial intervals (750–580 Ma) including two extending to low palaeomagnetic latitudes. Paucity of radiometric dates indicates the need for chronostratigraphic tools. Whereas the marine
87
Sr/
86
Sr signatures show a steady rise, δ
13
C fluctuates, the most reproducible variations being negative signatures in carbonate caps to glacial units, but more diagenetic work is needed. Four conceptual models for the icehouse conditions are contrasted: Zipper-Rift Earth (diachronous glaciation related to continental rift margins), High-tilt Earth (high-obliquity and preferential low-latitude glaciation), Snowball Earth (extreme glaciation related to runaway ice–albedo feedback) and Slushball Earth (coexistence of unfrozen oceans and sea-level glaciers in the tropics). Climate models readily simulate runaway glaciation, but the Earth may not be able to recover from it. The Slushball state requires more extensive modelling. Biogeochemical models highlight the lack of CO
2
buffering in the Neoproterozoic and the likely transition from a methane- to a CO
2
-dominated climate system. Relevant processes include tropical weathering of volcanic provinces, and new land biotas stimulating both clay mineral formation and P delivery to the oceans, facilitating organic C burial. Hence a step change in the Earth System was probably both facilitated by organisms and responsible for moderating Phanerozoic climate.
The geochronology of large igneous provinces, terrestrial impact craters, and their relationship to mass extinctions on Earth
Authors: Kelley Simon
Published: August 2007

The relationship between sudden catastrophic events and sudden mass extinctions on Earth has attracted a great deal of research effort, including measurements of the absolute and relative ages of these events. The result has been a rapid improvement in the precision and accuracy of radiometric dates for large igneous provinces (LIPs), for which there is now a consensus on the peak eruption times over the last 250 Ma. In parallel there has been a more gradual improvement in the radiometric dates for craters formed by hypervelocity impacts (HVIs) of asteroids and comets with Earth. The absolute ages of the largest craters are known to within a few million years but the ages of many smaller craters are poorly constrained. In addition, whereas relatively few LIPs have formed in the last 250 Ma, at least one HVI crater larger than 20 km diameter has formed on Earth every million years (only 25 such craters have been discovered), so coincidence between the ages of HVI crater formation and ages of mass extinctions is related as much to crater preservation as to coincidence of the events. The difference in quality of geochronology between HVIs and LIPs is the result of differing availability of samples: LIPs cover large areas and present an array of basalt samples suitable for dating, whereas HVI craters are often poorly preserved and present few datable samples. The radiometric data for preserved HVIs and LIPs are now sufficiently precise and accurate for us to be confident that there is no one-to-one correlation between either LIPs or HVIs and global mass extinctions of life on Earth. However, there is a close association between a significant number of LIPs and sudden environmental change, and a very close association between at least one massive HVI crater formation and a mass extinction. Further, there is no apparent correlation between HVIs and LIPs and thus no reason to suggest a causative relationship. Finally, the radiometric dating of HVI craters indicates several clusters in the geological record, but the correlation with sudden environmental change is no better than for large craters.
Tyrosinase from Rhizobium etli Is Involved in Nodulation Efficiency and Symbiosis-Associated Stress Resistance
Authors: Piñero Silvia , Rivera Javier , Romero David , Cevallos Miguel Angel , Martínez Alfredo , Bolívar Francisco , Gosset Guillermo
Published: August 2007

Tyrosinase (EC 1.14.18.1) is a monophenol oxidase responsible for the synthesis of the black pigment known as melanin. The tyrosinase gene (melA) is plasmid-encoded in many rhizobial species. In Rhizobium etli CFN42, the genetic location of melA in the symbiotic plasmid (p42d) and its RpoN-NifA regulation suggest an involvement in symbiosis. In this work, we analyzed the symbiotic phenotype of a streptomycin-resistant derivative of CFN42 (CE3), a melA mutant (SP2) and a complemented strain (SP66), demonstrating that melA inactivation reduced nodule formation rate and diminished total nodule number by 27% when compared to the CE3 strain. The nitrogen fixation capacity of the mutant strain was not affected. Also, in vitro assays were performed where the resistance of CE3, SP2 and SP66 strains to H2O2 was evaluated; the melA mutant strain was consistently less resistant to peroxide. In another series of experiments, Escherichia coli W3110 strain expressing R. etli melA displayed enhanced resistance to p-hydroxybenzoic, vanillinic and syringic acids, which are phenolic compounds frequently found in the soil. Our results are the first to demonstrate a specific role for tyrosinase in R. etli: this enzyme is required during early symbiosis, apparently providing resistance against reactive oxygen species and phenolic compounds generated as part of the plant protective responses.
UDP-Acetyl-Mannosamine Dehydrogenase Is an Endogenous Protein Substrate of Staphylococcus aureus Protein-Tyrosine Kinase Activity
Authors: Soulat D. , Grangeasse C. , Vaganay E. , Cozzone A.J. , Duclos B.
Published: August 2007

The in silico analysis of the amino acid sequences deduced from the complete genome sequence of Staphylococcus aureus suggested the presence of two protein tyrosine kinase activities, each split into two distinct polypeptides, respectively Cap5A1/Cap5B1 and Cap5A2/Cap5B2, like in some other Gram-positive bacteria. To check this prediction, the corresponding genes were cloned and overexpressed, and the four corresponding proteins were purified by affinity chromatography and assayed for phosphorylating activity in vitro. Individually, none of them was found to autophosphorylate. However, when Cap5B2 was incubated in the presence of Cap5A2 or, with a larger efficiency, in the presence of Cap5A1, this protein exhibited intensive autokinase activity, occurring selectively at tyrosine residues. On the other hand, whatever the protein combination assayed, Cap5B1 did not present any phosphorylating activity. In search of a possible role for the phosphorylation reaction mediated by Cap5B2, an endogenous substrate of this kinase was characterized. This substrate, termed Cap5O, is the enzyme UDP-acetyl-mannosamine dehydrogenase involved in the cascade of reactions leading to the synthesis of the bacterial capsule. It represents the first endogenous substrate for a tyrosine kinase activity so far identified in S. aureus. The analysis of its dehydrogenase activity showed that it was positively controlled by its phosphorylation at tyrosine.
Genetic Fingerprints of Parasites Causing Severe Malaria in a Setting of Low Transmission in Sudan
Authors: A-Elbasit Ishraga E. , A-Elgadir Thoraya M.E. , ElGhazali Gehad , Elbashir Mustafa I. , Giha Hayder A.
Published: August 2007

In this study we intended to examine the extent of genetic diversity of Plasmodium falciparum parasites causing severe malaria (SM). For this purpose, 100 parasite isolates were obtained from patients with SM and uncomplicated malaria, from an area of low and unstable malaria transmission in Sudan. The diversity of infection (DOI) was estimated by relating the number of the different parasite genotypes that were detected to the total number of parasites that were genotyped (parasite population/subpopulation). We used different molecular markers individually (pfcrt-76, pfmr1-86, GLURP size and MSP2 family and size) and as a group to set a multilocus genetic profile for each parasite isolate. The DOI as estimated by MSP2 and GLURP was 0.553 and 0.435, respectively. However, combination of all four molecular markers (multilocus genetic profile) revealed a fingerprint pattern of genetic diversity with a DOI of 0.936, indicating that in SM infection, diversity is the rule and homogeny is the exception. Furthermore, our clinical data suggest that the virulence markers might also be more diverse than expected. In conclusion, the results are unexpected and overturn the assumption that parasites causing SM are a limited subpopulation of virulent parasites or of a clonal nature. However, it was more likely that there was a genetically unique parasite in each infection.
Molecular Characterization of a Novel Family VIII Esterase from Burkholderia multivorans UWC10
Authors: Rashamuse Konanani J. , Burton Stephanie G. , Stafford William H.L. , Cowan Don A.
Published: August 2007

An esterase producing Burkholderia multivorans UWC10 strain was isolated by culture enrichment. A shotgun library of B. multivorans UWC10 genomic DNA was screened for esterase activity and a recombinant clone conferring an esterolytic phenotype was identified. Full-length sequencing of the DNA insert showed that it consisted of a single open reading frame (ORF1) encoding a predicted protein of 398 amino acids. ORF1 (termed EstBL) had a high protein sequence identity to family VIII esterases. The EstBL primary structure showed two putative serine motifs, G-V-S149-D-G and S74-V-T-K. The estBL gene was successfully over-expressed in E. coli and the encoded protein purified by a combination of ammonium sulphate fractionation, hydrophobic interaction, ion exchange and size exclusion chromatographies. Biochemical assays confirmed EstBL esterase activity and revealed a preference for short-chain p-nitrophenyl and β-naphthyl esters (C2-C4) with no activity against β-lactam substrates. Secondary structure predictions indicated that EstBL adopts the α/β fold, which is common to all esterases.
Combined Brief Dynamic Therapy and Pharmacotherapy in the Treatment of Major Depressive Disorder: A Pilot Study
Authors: Maina Giuseppe , Rosso Gianluca , Crespi Chiara , Bogetto Filippo
Published: August 2007

Background: The relative efficacy of supplemental psychotherapy in the treatment of depression is still a matter of debate. Moreover, the superiority of brief dynamic therapy (BDT) over supportive psychotherapies is not well established. The aim of this study is to compare the efficacy of BDT added to medication with that of brief supportive psychotherapy (BSP) added to medication in the treatment of major depressive disorder. Method: A 12-month randomized clinical trial compared BDT (n = 18) with BSP (n = 17) combined with antidepressants in outpatients with major depressive disorder. Both psychotherapies were added during the first 6 months of the trial; all patients continued to be treated with only pharmacotherapy (paroxetine or citalopram) in the following 6-month continuation phase. Efficacy was assessed using the 17-item Hamilton Rating Scale for Depression (HAM-D), the Hamilton Rating Scale for Anxiety and the Clinical Global Impression (CGI). The data analysis was conducted on two samples: the per-protocol (PP) sample and the observed-cases (OC) sample. Results: Thirty-two patients completed the study. Although at the end of the combined therapies (T2) no differences emerged between the two treatment approaches, the group of patients treated with BDT showed a further clinical improvement at the end of the study (T3): a significant reduction in symptomatology emerged on the HAM-D (PP sample: F = 75.154, p = 0.03; OC sample: F = 67.149, p = 0.022) and on the CGI total scores (PP sample: F = 78.527, p = 0.016; OC sample: F = 74.104, p = 0.007). The difference in remission rates on the HAM-D (75 vs. 12.5% at T3) is statistically significant favoring BDT. Conclusions: BDT combined with antidepressants is preferable to supportive psychotherapy combined with medication in the treatment of outpatients with major depression.
Clinical Characteristics of Dementia Associated with Argyrophilic Grain Disease
Authors: Steuerwald Gertrud M. , Baumann Thomas P. , Taylor Kirsten I. , Mittag Michael , Adams Heiner , Tolnay Markus , Monsch Andreas U.
Published: August 2007

Background/Aims: We aimed at characterizing the clinical features of dementia associated with argyrophilic grain disease (AgD). Methods: Relatives or close friends of 24 individuals with autopsy-confirmed AgD and 29 patients with autopsy-confirmed Alzheimer’s disease (AD) were administered a novel Retrospective Dementia Inventory to assess the cognitive, behavioral and affective symptoms of the deceased patients. Results: AgD patients showed less severe impairments in memory, language, attention and executive function than AD patients.Conclusion: Compared to AD patients, individuals suffering from AgD appear to present with comparable deficits in behavior and affect but relatively spared cognitive functioning.
Desalted Deep Sea Water Increases Transformation and Homologous Recombination Efficiencies in Dictyostelium discoideum
Authors: Kuwayama Hidekazu , Nagasaki Akira
Published: August 2007

The life cycle of Dictyostelium discoideum consists of many cellular and developmental aspects. By virtue of its relatively high transformation efficiency and a small haploid genome, this organism has proven to be advantageous for characterizing gene functions. However, a much higher transformation efficiency is required as one of the prerequisites for unraveling gene function on a genome-wide scale. In this study, we describe the positive effect of desalted deep sea water, when used as a solvent medium, on the transformation and homologous recombination efficiencies in Dictyostelium. A standard Dictyostelium medium HL5 containing desalted deep sea water, HL5dsw, distinctly increased both the transformation and homologous recombination efficiencies by approximately 2- to 3-fold. Furthermore, we observed that the growth of cells in HL5dsw both before and after electroporation contributed to the increase in transformation efficiency. These results indicate that a simple modification of the solvent medium remarkably enhanced the isolation of transformants and gene-targeted clones, which had previously been difficult to isolate.
Why Is The Song of Moses in the Book of Deuteronomy?
Authors: Leuchter Mark
Published: August 2007

Determining the compositional origins of The Song of Moses has long proved to be a difficult task, with some scholars favoring an early (pre-8th century) date and others looking to a date in the Josianic period or later. New light may be shed on this problem by asking not when the Song was composed but by determining its function within the Book of Deuteronomy. In order to do this, a date of the Song's redaction into Deuteronomy must be established. The present study suggests that this redaction is best seen as occurring during the reign of Josiah, bestowing upon the Song a hermeneutical purpose via its place in the overall structure of the Josianic edition of Deuteronomy. Viewed from this perspective, the Song can be seen as contributing to the northern Levitical interests of the Deuteronomists and serving propagandistic aims in relation to Josiah's ambitions in the north. ese observations are suggestive of the Song's compositional origins among northern Levites in the early days of the monarchic period.
Social Epistemology
Authors: Jacobson Nora
Published: August 2007

Knowledge transfer and exchange has become an increasingly important practice in the arena of publicly funded health and social research. Throughout its history, investigators have used a variety of borrowed theories to explore and explain the determinants, processes, and results of knowledge transfer. As the context in which knowledge transfer takes place has changed, so too has the theory used to explore and explain the process. This article reviews the role of theory in knowledge transfer and exchange research and proposes a novel source for potentially useful new theory in the current context: social epistemology.
Green Tea Solution Individually Solubilizes Single-walled Carbon Nanotubes
Authors: Nakamura Genki , Narimatsu Kaori , Niidome Yasuro , Nakashima Naotoshi
Published: August 2007

We describe the finding that green tea and catechins individually dissolve single-walled carbon nanotubes (SWNTs). UV–visible–near-IR absorption, photoluminescence, Raman spectroscopy, and atomic force microscopy were used to characterize the solubilized aqueous nanotube solutions.
Circular Arrangement of Mesogens Induced in Bragg-type Polarization Holograms of Thick Azobenzene Copolymer Films with a Tolane Moiety
Authors: Shishido Atsushi , Ishiguro Makoto , Ikeda Tomiki
Published: August 2007

Bragg-type polarization holograms were recorded in thick copolymer films with tolane and azobenzene moieties by interfering two orthogonal circularly polarized beams at 488 nm. Observation of the films with a polarizing optical microscope revealed that circular alignment of molecules was induced along a grating vector. An incident reading beam at 633 nm was efficiently diffracted, depending on its polarization state and incident direction.
Double Thienylation of Alkynes in the Platinum(II)-catalyzed Reaction of Thiophenes with Propiolic Acids
Authors: Keita Mory Laye , Mizuhara Tomohiro , Oyamada Juzo , Kitamura Tsugio
Published: August 2007

Platinum-catalyzed hydroarylation of alkynes was applied to thiophenes. Reaction of thiophenes with ethyl propiolate in trifluoroacetic acid in the presence of a K2PtCl4/AgOTf catalyst gave bis(substituted thienyl)propionates in good yields. The same Pt-catalyzed reaction with propiolic acid proceeded efficiently to provide bis(substituted thienyl)propionic acids in high yields.
Phenotype of a Calbindin-D9k Gene Knockout Is Compensated for by the Induction of Other Calcium Transporter Genes in a Mouse Model
Authors: Lee Geun-Shik , Lee Kun-Yeong , Choi Kyung-Chul , Ryu Young-Han , Paik Sang Gi , Oh Goo Taeg , Jeung Eui-Bae
Published: August 2007

CaBP-9k may be involved in the active calcium absorption and embryo implantation. Although we generated CaBP-9k KO mice to explore its function, no distinct phenotypes were observed in these KO mice. It can be hypothesized that TRPV5 and 6 and plasma membrane calcium ATPase 1b may play a role in the regulation of calcium transport to compensate CaBP-9k deficiency in its KO model.

Introduction: Active calcium transport in the duodenum and kidney is carried in three steps: calcium entry through epithelial Ca2+ channels (TRPV5 and TRPV6), buffering and/or transport by calbindin-D9k (CaBP-9k) and -D28k (CaBP-28k), and extrusion through the plasma membrane calcium ATPase 1b (PMCA1b) and sodium/calcium exchanger 1. Although the molecular mechanism of calcium absorption has been studied using knockouts (KOs) of the vitamin D receptor and CaBP-28k in animals, the process is not fully understood.

Materials and Methods: We generated CaBP-9k KO mice and assessed the phenotypic characterization and the molecular regulation of active calcium transporting genes when the mice were fed different calcium diets during growth.

Results: General phenotypes showed no distinct abnormalities. Thus, the active calcium transport of CaBP-9k–null mice proceeded normally in this study. Therefore, the compensatory molecular regulation of this mechanism was elucidated. Duodenal TRPV6 and CaBP-9k mRNA of wildtype (WT) mice increased gradually during preweaning. CaBP-9k is supposed to be an important factor in active calcium transport, but its role is probably compensated for by other calcium transporter genes (i.e., intestinal TRPV6 and PMCA1b) during preweaning and renal calcium transporters in adult mice.

Conclusions: Depletion of the CaBP-9k gene in a KO mouse model had little phenotypic effect, suggesting that its depletion may be compensated for by calcium transporter genes in the intestine of young mice and in the kidney of adult mice.
Zur Strafwürdigkeit automatisierter Verhaltensweisen
Authors: Merkel Grischa
Published: August 2007

In der Literatur gilt die Strafwürdigkeit automatisierter Verhaltensweisen weiterhin als nicht abschließend geklärt. Obwohl sich nur Wenige dezidiert schon gegen die Handlungsqualität von Automatismen aussprechen, scheint der Mehrheit jedenfalls bewusst, dass die Bejahung des Handlungsmerkmals in den entsprechenden Fällen eine gewisse Dissonanz mit den überkommenen Handlungslehren des Strafrechts erzeugt. Dabei ist die Schwierigkeit einer Zuordnung der automatisierten Verhaltensweisen offenbar eine zweifache: Einerseits können sie sich, wie die Reflexe, die gemeinhin als sog. Nichthandlungen angesehen werden, in einer motorisch einfachen Reizantwort erschöpfen; sie können aber auch als komplexe Reaktionen auf unspezifische situative Ereignisse erfolgen, so dass ganz unterschiedliche Bewegungsabläufe möglich sind. Daher sind sie äußerlich von den für das Selbstbild des Menschen typischen „Wahlentscheidungen“ schwer abzugrenzen. Auf der anderen Seite widersetzen sie sich einer Einordnung in den Handlungsbegriff, da diese Bewegungen zwar im Wachzustand, aber, jedenfalls in den strafrechtlich relevanten Fällen, zumeist als unmittelbare Reaktion auf ein unvorhersehbares Ereignis derart spontan erfolgen, dass der jeweiligen Person keine Zeit zu einer überlegten Handlung bleibt und sie „einfach nur reagiert“. Dies sei, so wird gesagt, darauf zurückzuführen, dass ein vormals erlernter Vorgang nunmehr lediglich auf einen Reiz hin „abgerufen“ wird. Die mehrheitlich vertretenen Handlungsbegriffe setzen dagegen eine bewusst kontrollierte Steuerung bei strafrechtlich relevanten Bewegungen voraus. Eben dieses Merkmal scheint den automatisierten Verhaltensweisen aber gerade zu fehlen – daher deren Bezeichnung als „automatisiert“. Auch nach der Rechtsprechung soll eine Handlung jedenfalls dann nicht vorliegen, wenn der „natürliche Wille“, die „Beherrschbarkeit durch den Willen“, die „Willensbetätigung“, der „Willensakt“ oder „Willensentschluß“ nicht festgestellt werden kann; gleichwohl bejaht sie heute ebenfalls die Strafwürdigkeit automatisierter Verhaltensweisen.
Die Bedeutung der Entsprechungsklausel beim Betrug durch Schweigen
Authors: Kargl Walter
Published: August 2007

I. Einführung

1. Entwicklung in der Rechtsprechung

Das Institut des Betrugs durch Unterlassen blickt auf eine lange Rechtsprechungstradition zurück. Den Grundstein für die Bestrafung einer Täuschung durch Schweigen legte das Reichsgericht in einem Urteil vom 28. November 1889, in dem erstmalig auf die Möglichkeit einer Gleichstellung zwischen aktiver Täuschung und schlichtem Nichthandeln hingewiesen wurde. Bereits ein Jahr später wurde mit dem Hinweis Ernst gemacht. Am 3. Oktober 1890 erfolgte im Rahmen des § 263 StGB eine Verurteilung wegen „unredlichen“ Schweigens. Zur Begründung wurden die Grundsätze über Kommissivdelikte durch Unterlassen herangezogen, wonach eine Bestrafung des Angeklagten in Betracht komme, „wenn derselbe infolge vorausgegangenen Tuns oder kraft einer sonst bestehenden Rechtspflicht die in Frage stehende Tatsache mitteilen muss“. Fortan gehört die Anwendung der Leitsätze der unechten Unterlassungsdelikte auf den Betrug durch Schweigen zur gefestigten Rechtsprechung. Sofern auf den Wortlaut des § 263 StGB eingegangen wird, zählt die Verortung des Schweigens unter das Tatbestandsmerkmal der „Unterdrückung einer wahren Tatsache“ ebenfalls zum gesicherten Bestand der Judikatur.
Grundlagen des konstruktivistischen Unternehmensschuldbegriffes
Authors: Díez Carlos Gómez-Jara
Published: August 2007

I. Problemstellung

Soll das deutlichste Argument gegen eine Unternehmensstrafbarkeit benannt werden, so entscheidet sich der Dogmatiker wahrscheinlich rasch für die Schuldunfähigkeit des Unternehmens. Die Gründe dafür sind zahlreich und bekannt: Unmöglichkeit eines gegen das Unternehmen zu formulierenden sozial-ethischen Schuldvorwurfs; Untauglichkeit des Unternehmens als Normadressat; Mangel des Unternehmens an subjektbezogener Reflexionsfähigkeit; Koordinierungsschwierigkeiten zwischen Unternehmensschuldzurechung und Organsschuldzurechung, unter anderen. Es kann behauptet werden, dass die h. M. in der deutschen Strafrechtsdogmatik das Konzept einer echten Unternehmensschuld ablehnt. Ganz in die Gegenrichtung aber bewegen sich die Tendenzen in der Europäischen Union; dort gewinnt die strafrechtliche Verantwortlichkeit von Unternehmen an Boden, und dies mit zunehmender Geschwindigkeit. Die neuen Regelungen in der Schweiz, Polen, Spanien und der Europäischen Union stellen eine klare Bestätigung der europäischen Tendenz dar, Unternehmen als Strafrechtspersonen zu betrachten. Obwohl in Deutschland jüngste entsprechende Vorstöße, um eine solche Verantwortlichkeit einzuführen, keinen Erfolg gehabt haben, ist es wahrscheinlich eine Zeitfrage, dass neue legislatorische Vorschläge in naher Zukunft präsentiert werden – sei es aufgrund nationaler Bedürfnisse, sei es wegen europäischer Verpflichtungen.