bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of 2,5‐Dihydrobenzo[b]oxepines and 5,6‐Dihydro‐2H‐benzo[b]oxocines Based on a “[3 + 3] Cyclization‐Olefin‐Metathesis” Strategy.
Authors: Nguyen Van Thi Hong , Bellur Esen , Langer Peter
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
A Concise Method for Synthesis of Diaryl Aryl‐ or Alkylphosphonates.
Authors: Yao Qiang , Levchik Sergei
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Sequential Cycloaddition Approach to the Tricyclic Core of Vibsanin E. Total Synthesis of (.+‐.)‐5‐epi‐10‐epi‐Vibsanin E.
Authors: Davies Huw M. L. , Loe Oeystein , Stafford Douglas G.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of the Cyclic Isomer of the Vitamin K1 Dihydro Derivative (Naphthotocopherol) and Its Analogues with the Shortened, and ω‐Functionalized Side Chain.
Authors: Spivak A. Yu. , Knyshenko O. V. , Mallyabaeva M. I. , Odinokov V. N.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Toward a Total Synthesis of the Novel Polyketide Natural Product Spiculoic Acid A.
Authors: Mehta Goverdhan , Kundu Uday Kumar
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Synthesis of the Novel Series of Bispyridinium Compounds Bearing (E)‐But‐2‐ene Linker and Evaluation of Their Reactivation Activity Against Chlorpyrifos‐Inhibited Acetylcholinesterase.
Authors: Musilek Kamil , Kuca Kamil , Jun Daniel , Dohnal Vlastimil , Dolezal Martin
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Polymeric Sensor Materials: Toward an Alliance of Combinatorial and Rational Design Tools?
Authors: Potyrailo Radislav A.
Published: April 2006

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
System identification of a concrete arch dam and calibration of its finite element model
Authors: Alves S. W. , Hall J. F.
Published: April 2006

A magnitude 4.3 earthquake occurred near Pacoima Dam on 13 January 2001. An accelerometer array that had been upgraded after the Northridge earthquake recorded the motion with 17 channels on the dam and the dam–foundation interface. Using this data, properties of the first two modes are found from a system identification study. Modal properties are also determined from a forced vibration experiment performed in 2002 and indicate a significantly stiffer system than is estimated from the 2001 earthquake records. The 2001 earthquake, although small, must have induced temporary nonlinearity. This has implications for structural health monitoring. The source of the nonlinear behaviour is believed to be loss of stiffness in the foundation rock. A finite element model of Pacoima Dam is constructed and calibrated to match modal properties determined from the system identification study. A dynamic simulation of the 2001 earthquake response produces computed motions that agree fairly well with the recorded ones. Copyright © 2006 John Wiley & Sons, Ltd.
Mutational Analysis of the APC Gene in Cribriform‐Morula Variant of Papillary Thyroid Carcinoma
Authors: Uchino Shinya , Noguchi Shiro , Yamashita Hiroto , Yamashita Hiroyuki , Watanabe Shin , Ogawa Takahiro , Tsuno Akiko , Murakami Akiko , Miyauchi Akira
Published: April 2006

Introduction

Familial adenomatous polyposis (FAP) is an inherited autosomal dominant syndrome caused by germline mutations in the adenomatous polyposis coli (APC) gene. Papillary thyroid cancer is one of the extracolonic manifestations of FAP. A characteristic histologic feature of this type of thyroid tumor is the cribriform‐morula variant of papillary thyroid carcinoma (CMVPTC).

Methods

To investigate roles of the APC and β‐catenin genes in the development of CMVPTC, we examined germline and somatic mutations of these genes in a female patient with CMVPTC and FAP. The patient had undergone total colectomy at the age of 19 years and total thyroidectomy at age 25 years.

Results

Numerous tumors were disseminated in both lobes of the thyroid gland, and histopathologic examination revealed typical CMVPTC. DNA was extracted from peripheral blood leukocytes and 12 CMVPTC tumors, and exons 1–15 of the APC gene and exon 3 of the β‐catenin gene were examined. A germline mutation was detected in exon 13 of the APC gene, and this mutation generated a premature stop codon. Six somatic mutations (922delC, 1602delA, 1821delT, 1920delG, 2706del20, 2804insA) were found in the CMVPTC specimens. All mutations were truncating mutations in the N‐terminus of the APC protein. Loss of heterozygosity was not observed in the remaining tumor tissues without somatic APC mutations. There were no mutations of the β‐catenin gene in peripheral blood leukocytes or 12 CMVPTC specimens.

Conclusions

These results suggest that APC mutations play an important role in the development of CMVPTC and occur predominantly in the 5′ side of the APC gene between codons 308 and 935.
Progress in determining southern blue whiting (Micromesistius australis) target strength: results of swimbladder modelling
Authors: Dunford Adam J. , Macaulay Gavin J.
Published: April 2006

Southern blue whiting target strength (TS) results from Kirchhoff modelling of swimbladder casts scanned using a hand-held 3D laser scanner are presented. The data are compared with the relationship between TS and fish length used for New Zealand stock-assessment surveys; TS = 21.8 log10(fork length) − 72.8, at 38 kHz. This relationship has its origins in the relationship used for blue whiting (Micromesistius poutassou) in the northern hemisphere, and is based on measurements on juvenile cod (Gadus morhua). The results indicate that the blue whiting relationship is not appropriate for southern blue whiting, and suggest a much steeper slope, with TS = 38 log10(fork length) − 97, at 38 kHz. Sensitivity analyses indicate that further investigations of swimbladder tilt-angle distribution and swimbladder volume are unlikely to provide evidence to support the use of the blue whiting relationship for southern blue whiting.
Expression and Automated Purification of Acetoacetyl CoA Thiolase from Sunflower Cotyledon
Authors: Dyer James H. , Becker James , Geraldo Victor , Giron Mario
Published: April 2006

In the sunflower (Helianthus annuus L.) cotyledons, two distinguishable thiolase activities have been identified: acetoacetyl CoA thiolase (AACT), specifically active during oxidation of short chain acetoacetyl CoA, and 3-oxoacyl CoA thiolase (OACT), active towards short, medium, and long-chain acyl CoAs. The purpose of this research was to optimize the purification of the AACT expressed in bacteria. Escherischia coli (E. coli) with the full-length sunflower AACT cDNA cloned into the expression vector pBAD-His B was induced for production of the AACT using 0.2% arabinose. Optimizing the conditions for protein purification is often an extremely empirical process requiring several iterations of a basic protocol each with specific changes. This iterative process was simplified using the programmable Äkta chromatography system from Amersham Pharmacia (now GE Healthcare). Programming this system for automatic sample injection and variation of elution conditions allows for optimization of the protein purification protocol to be achieved overnight as opposed to taking a day for each iteration done manually. Once optimized, soluble AACT was purified from E. coli bacteria in one step using a His HiTrap HP column containing Ni-Sepharose resin in conjunction with the Äkta chromatography system. AACT activity was detected in the induced bacteria, whereas no activity was observed with the uninduced control.
Gendered Strategies for Success in the Early Nineteenth-Century Literary Marketplace: Mary Carr and the Ladies' Tea Tray
Authors: BRANSON SUSAN
Published: April 2006

In April 1815 Mary Clarke Carr submitted an insolvency petition to the Philadelphia Court of Common Pleas. The petition described how Carr had failed to take in the subscription monies owed for her magazine, The Intellectual Regale, or Ladies' Tea Tray, “and lost thereby at least $200 … the receipts not being sufficient for the support of herself and family.” As a consequence of her debts, Carr was forced to sell the rights to the magazine, along with “printing press types, printing apparatus, paper and all … & every other thing &c pertaining to the said ‘establishment.’” After collecting $256 from printer Thomas Smith in exchange for her property, Carr continued to struggle with her magazine for more than a year.
A model for the decay of a wall shock in a large abrupt area change
Authors: Sloan S. A. , Nettleton M. A.
Published: April 2006

A series of initially planar shock waves was allowed to expand from a shock tube into a near half-space. The strength of the wall shock was measured at two positions on the slightly concave front wall. These measurements are compared with shock strengths predicted by a shock-dynamic model based on the cylindrical expansion of a critical shock. Chisnell's (1957) theory is used to account for the effect of the increasing surface area of the expanding wall shock, and Whitham's (1957) treatment to correct for the curvature of the wall. The critical shock strength is obtained from Skews’ (1967) experimental measurements of the Mach number of the self-similar wall shock following two-dimensional diffraction at a 90° edge.

The model predicts the relatively small degree of attenuation observed between the measuring stations, but overestimates the absolute shock strength. The most likely cause is that, in the early stages of expansion, the wall shock experiences further attenuation owing to its interaction with the expanding flow. These effects are shown to be short range and of negligible importance at the first measuring station, 1·86 tube diameters from the axis. Thus, using the experimental results at this station as the starting point, the model predicts accurately the shock strength at 3·76 diameters. It is concluded that Chisnell's theory can be applied to the weakening of the wall shock in ducts with large abrupt changes in cross-section only when the wall shock is some distance from the entrance to the area change.
Convection fluid dynamics in a model of a fault zone in the earth's crust
Authors: Kassoy D. R. , Zebib A.
Published: April 2006

Faulted regions associated with geothermal areas are assumed to be composed of rock which has been heavily fractured within the fault zone by continuous tectonic activity. The fractured zone is modelled as a vertical, slender, two-dimensional channel of saturated porous material with impermeable walls on which the temperature increases linearly with depth. The development of an isothermal slug flow entering the fault at a large depth is examined. An entry solution and the subsequent approach to the fully developed configuration are obtained for large Rayleigh number flow. The former is characterized by growing thermal boundary layers adjacent to the walls and a slightly accelerated isothermal core flow. Further downstream the development is described by a parabolic system. It is shown that a class of fully developed solutions is not spatially stable.
Mechanism of determination of the shedding frequency of vortices behind a cylinder at low Reynolds numbers
Authors: Nishioka Michio , Sato Hiroshi
Published: April 2006

Two kinds of experiment were made in the wake of a cylinder at Reynolds numbers ranging between 20 and 150. One was a close look at the structure of the vortex street with a stationary cylinder at Reynolds numbers greater than 48. The other experiment was made at lower Reynolds numbers with a cylinder vibrating normal to the flow direction. In this case an artificially induced small-amplitude fluctuation grows exponentially with the rate predicted by the stability theory. Because of the similarity between the two kinds of wake, we postulate that the shedding of the vortex at low Reynolds numbers is initiated by the linear growth, namely, the fluctuation with the frequency of maximum linear growth rate develops into vortex streets. By using the measured width of the wake at the stagnation point in the wake and the result of the stability theory, we could calculate the Strouhal number for Reynolds numbers ranging from 48 to 120. The predicted Strouhal numbers agree well with the values from direct measurements.
On wave-action and its relatives
Authors: Andrews D. G. , Mcintyre M. E.
Published: April 2006

Conservable quantities measuring ‘wave activity’ are discussed. The equation for the most fundamental such quantity, wave-action, is derived in a simple but very general form which does not depend on the approximations of slow amplitude modulation, linearization, or conservative motion. The derivation is elementary, in the sense that a variational formulation of the equations of fluid motion is not used. The result depends, however, on a description of the disturbance in terms of particle displacements rather than velocities. A corollary is an elementary but general derivation of the approximate form of the wave-action equation found by Bretherton & Garrett (1968) for slowlyvarying, linear waves.

The sense in which the general wave-action equation follows from the classical ‘energy-momentum-tensor’ formalism is discussed, bringing in the concepts of pseudomomentum and pseudoenergy, which in turn are related to special cases such as Blokhintsev's conservation law in acoustics. Wave-action, pseudomomentum and pseudoenergy are the appropriate conservable measures of wave activity when ‘waves’ are defined respectively as departures from ensemble-, space- and time-averaged flows.

The relationship between the wave drag on a moving boundary and the fluxes of momentum and pseudomomentum is discussed.
The spectral broadening of sound by turbulent shear layers. Part 2. The spectral broadening of sound and aircraft noise
Authors: Campos L. M. B. C.
Published: April 2006

It has been observed experimentally by Candel, Julienne & Julliand (1975) that a monochromatic test tone generated by a source inside a jet is received outside as a broad frequency band of definite shape. This phenomenon of spectral broadening occurs during transmission through the shear layer, which generally has a randomly irregular and unsteady shape, contains in addition distributed turbulence, and separates the jet and the ambient medium. We show in the first place that, in the audible range of frequencies, neither the approximation which treats the shear layer as a scattering interface with a convected undulating shape nor the opposite, high frequency limit obtained by means of asymptotic estimation of integrals derived for the diffraction of rays in turbulence is sufficient to provide a satisfactory theory of the observations. The refraction integrals obtained in part 1 have to be evaluated exactly in order to account for the phenomenon of spectral broadening, the methods used possibly being of interest in other branches of wave theory. The formation of the transmitted spectrum from an incident tone can be illustrated by representing a simple shear layer as an array of elements each re-radiating energy received from the source with its own characteristic attenuation and frequency shift. A computer program is used to obtain spectra under conditions corresponding to the experiments of Candel, Guédel & Julienne (1975) and gives encouraging agreement with their measurements, which were made with high frequency sources immersed in low speed jets. The theory can also be applied to the prediction of spectra received at various angles to the axis of high subsonic jets, but depends on extrapolation when supersonic exhausts are considered. We conclude with an example of the possible relevance of spectral broadening as a means of reducing the noise disturbance from current jet-powered aircraft, such as Concorde.
Magnetohydrodynamic flows and turbulence: a report on the Second Bat-Sheva Seminar
Authors: Branover H. , Hunt J. C. R. , Proctor M. R. E. , Pierson E. S.
Published: April 2006

This paper is a summary of the Second Bat-Sheva Seminar on magnetohydrodynamic (MHD) Flows and turbulence. It was held in the University of the Negev, Israel, on 28-31 March 1978, with 64 participants from 7 countries. Reviews and research papers were presented on the general theory of MHD, MHD duct flows (with emphasis on novel aspects such as non-uniform fields and fluid properties, bends, free-surface effects and longitudinal diffusion), two-phase flows (especially those likely to occur in a liquid-metal generator), turbulence and instabilities, and electrically driven flows (with new results presented for the theory of laminar and turbulent flows in induction furnaces, and for the theory of thermo-electrically driven flows in transverse magnetic fields). One day of the conference was devoted to turbulence, mainly without magnetic fields, with reviews and new results presented on the theory and measurements of coherent structures, intermittency at high Reynolds number, methods of calculating shear flows, and measurement techniques. The seminar was a strange mixture of people and topics, which produced some interesting papers and some useful discussion.
A numerical comparison of velocity-based and strain-based Lagrangian-history turbulence approximations
Authors: Herring Jackson R. , Kraichnan Robert H.
Published: April 2006

The abridged Langrangian-history direct-interaction (ALHDI) approximation (Kraichnan 1966) and the strain-based abridged Lagrangian-history direct-interaction (SBALHDI) approximation (Kraichnan & Herring 1978) are integrated numerically for isotropic turbulence in two and three dimensions and compared with data. At moderate Reynolds numbers in three dimensions, comparison with the computer simulations by Orszag & Patterson (1972) shows that the ALHDI gives numerically excessive energy transfer in the dissipation range while the SBALHDI approximation displays satisfactory accuracy in all ranges. In two dimensions, both approximations are in reasonable agreement with the simulations of Herring et al. (1974), the ALHDI approximation showing the better accuracy of the two at low wavenumbers. At high wavenumbers the SBALHDI approximation again transfers less energy than the ALHDI approximation but the effect is less marked than in three dimensions and the two curves straddle the data. High Reynolds number integrations of both approximations in three dimensions agree well with the tidal-channel inertial- and dissipationrange data of Grant, Stewart & Moilliet (1962), the SBALHDI approximation yielding a somewhat larger value of Kolmogorov's constant than the ALHDI approximation. The origin of the difference in straining efficiency between the two approximations at high wavenumbers and of the dependence of this difference on dimensionality is exhibited by application to the stretching of small scales of a convected passive scalar field. In three dimensions the SBALHDI approximation gives markedly larger values of the constant in Batchelor's (1959) k−1 spectrum range than the ALHDI approximation and is in better agreement with experiment. The SBALHDI values of Batchelor's constant satisfy Gibson's (1968) lower bound while the ALHDI values do not.
Scattering and distortion of the unsteady motion on transversely sheared mean flows
Authors: Goldstein M. E.
Published: April 2006

It is shown that the pressure and velocity fluctuations of the unsteady motion on a transversely sheared mean flow can be expressed entirely in terms of the derivatives of two potential functions. One of these is a convected quantity (i.e. it is frozen in the flow) that can be specified as a boundary condition and is related to a transverse component of the upstream velocity field. The other can be determined by solving an inhomogeneous wave equation whose source term is also a convected quantity that can be specified as a boundary condition in any given problem. The latter is related to the curl of the upstream vorticity field. The results are used to obtain an explicit representation of the three-dimensional gust-like or hydrodynamic motion on a transversely sheared mean flow. It is thereby shown that this motion is ‘driven’ entirely by the two convected quantities alluded to above.

The general theory is used to study the interaction of an unsteady flow with a scmi-infinite plate embedded in a shear layer. The acoustic field produced by this interaction is calculated in the limits of low and high frequency. The results are compared with experimental one-third octave sound pressure level radiation patterns. The agreement is found to be excellent, especially in the low frequency range, where the mean-flow and convective effects are shown to have a strong influence on the directivity of the sound.
A modelling of large eddies in an axisymmetric jet
Authors: Acton E.
Published: April 2006

Crow & Champagne (1971), Bechert & Pfizenmaier (1975) and Moore (1977) have observed that the growth, mixing and noise production of jet flows are sensitive to harmonic forcing. This paper describes an attempt to model numerically certain features of these flows. The model flow is restricted to be axisymmetric and is consequently unrepresentative of the detailed structure in a real jet. Nonetheless, it is found that reasonable qualitative agreement exists between the results of the model and experiments as far as the large eddies are concerned. This suggests that a substantial part of the large-scale structure in a jet is essentially axisymmetric. Harmonic excitation is also applied to the model jet and the changes in frequency and amplitude of the excitation cause distinct changes in the wavelengths of the jet eddies. This resulting large-eddy behaviour is consistent with many features of the nonlinear behaviour observed experimentally in forced jets.
Fluid flow in a hemispherical container induced by a distributed source of current and a superimposed uniform magnetic field
Authors: Craine R. E. , Weatherill N. P.
Published: April 2006

In arc welding electromagnetic forces are thought to be the major cause of motion in the weldpool, and it has recently been found by experimentalists that the application to the workpiece of a uniform magnetic field normal to the weldpool surface appears to stabilize the welding process. In this paper we investigate motion in a hemisphere due to a stationary distributed current source with a superimposed uniform magnetic field applied parallel to the axis of symmetry. When inertial effects are ignored and a simple source-sink model of the current source is introduced, we obtain an analytic solution for the fluid flow valid for low currents and low applied fields. A numerical scheme is then developed to solve the full nonlinear-flow problem and results are obtained for the source-sink model of the current source and for a more realistic numerically constructed distributed current source. For values of the externally applied magnetic field and the current flowing through the hemisphere typical of those occurring in practical welding situations we discover that the flow in an axial section through the pool is radially outwards on the free surface. This is in the opposite direction to that generally predicted by the theory when there is no superimposed magnetic field.
Energetics of a linear array of hollow vortices of finite cross-section
Authors: Baker Gregory R.
Published: April 2006

The energetics of a linear array of hollow or stagnant-cored vortices of finite cross-section in an ideal fluid is studied in this paper. The results are useful in a discussion of the amalgamation of vortex structures in a turbulent mixing layer.
Nonlinear evolution and breakdown in unstable boundary layers
Authors: Craik A. D. D.
Published: April 2006

The nonlinear evolution and breakdown of laminar flow in the boundary layer on a flat plate is examined with the aim of making a closer comparison of theory and experiment than has been attempted previously. The importance of three-dimensionality is emphasized. It is concluded that many features of the nonlinear instability are consistent with existing linear and weakly nonlinear theories even as breakdown is approached. The development of the secondary instability, or ‘spike’, is also considered and suggestions for an improved theory of its growth are made.
Numerical analysis of the nonlinear propagation of plane periodic waves in a relaxing gas
Authors: Southern I. S. , Johannesen N. H.
Published: April 2006

The waves propagating from an oscillating plane piston into a vibrationally relaxing gas are calculated by an exact numerical method ignoring viscosity and heat conduction. Secondary effects due to the starting of the piston from rest and to acoustic streaming can be eliminated from the calculated flows, leaving a truly periodic progressive wave which can be analysed and compared with approximate solutions. It is found that for moderate amplitude waves nonlinearity is only important as a convective effect which produces higher harmonics, whereas dissipation is adequately described by linear theory.
Flow separation on a β-plane
Authors: Merkine Lee-Or
Published: April 2006

Boundary-layer structure of prograde and retrograde rotating flows past a cylinder on a β-plane is investigated. It is found that β inhibits boundary-layer separation for prograde flows but it exerts no influence on the boundary-layer structure for retrograde flows. The results agree with the few available experimental observations.
Mixing across a density interface produced by grid turbulence
Authors: Linden P. F.
Published: April 2006

The mixing produced by dropping a horizontal grid through a sharp density interface is examined experimentally. The fraction of the available kinetic energy used to mix the fluid, the flux Richardson number Rf, is measured as a function of the overall Richardson number Ri0. It is found that Rf increases from zero as Ri0 does, reaches a maximum, and then decreases with further increase in Ri0. The final interface thickness is found to be a decreasing function of Ri0, and the equivalent vertical diffusion coefficient is calculated. Qualitative observations of the flow show that the final stages of the decay of motion in the interface are characterized by pancake-shaped modes with large horizontal and small vertical scales.
The containment of an oil slick by a boom placed across a uniform stream
Authors: Pietro N. D. Di , Cox R. G.
Published: April 2006

A small region (called the surface tension region) where pressure differences across the oil–water and oil–air interfaces are important is shown to exist between the gravity viscous and monolayer regions in a spreading oil slick (Di Pietro, Huh & Cox 1978). The importance of this new region is that (i) it is necessary in order to connect the gravity–viscous and monolayer regions and (ii) it is a region where slopes of interfaces are large. This idea is used to find the thickness profile of an oil layer contained upstream of a barrier (an oil boom) placed across a channel in which water is flowing at a constant velocity. The assumption is also made that the velocity difference across the oil layer is small compared with the water velocity. The general conditions for the validity of the results are then discussed together with the modifications to the theory which are necessary if the boundary layer in the water below the oil should be turbulent rather than laminar. Good agreement is found to exist between experimental results for unsteady spreading on quiescent water in a channel and the results of the theory applied to this situation assuming quasi-steady spreading.
Decadal variability of the Indian Ocean cross‐equatorial exchange in SODA
Authors: Schoenefeldt Rena , Schott Friedrich A.
Published: April 2006

The mean meridional circulation across the equator in the Indian Ocean is characterized by the shallow Cross‐Equatorial Cell (CEC). At the western boundary, the Somali Current transports thermocline waters northward which then upwell, mostly off Northeast Africa. The upwelled waters are taking up heat and then exported back southward by southward near‐surface Ekman and Sverdrup transports. The CEC is closed by subduction in the southeastern subtropics and includes contributions from the Indonesian Throughflow. In an analysis of output from the SODA assimilation, a decadal slowdown of the different branches of the CEC is demonstrated here.
Our favourite alternative splice site
Authors: Lerivray Hubert , Méreau Agnès , Osborne H. Beverley
Published: April 2006

Alternative splicing is a widespread mechanism in mammals that generates several mRNAs from one gene, thereby creating genetic diversity of the genome. Variant splice patterns are often specific to different stages of development or particular tissues, and alternative splicing defects are being more frequently detected in genetic diseases and cancers. The increasingly important role of alternative splicing in the function and the regulation of cellular process makes it critical to have an easy‐to‐use data repository for the biological and medical research communities. We have compared web resources that give access to information on alternatively spliced genes, and the FAST DB (Friendly Alternative Splicing and Transcripts DataBase) site came out as our favourite.
Strain rate sensitivity of face-centered-cubic nanocrystalline materials based on dislocation deformation
Authors: Lian Jianshe , Gu Changdong , Jiang Qing , Jiang Zhonghao
Published: April 2006

The relationship between strain rate sensitivity and activation volume for face-centered-cubic metals is proposed based on the bow-out model of single dislocation from its source, which gives reasonable prediction of the enhanced strain rate sensitivity that occurs in nanostructured and ultrafine grained Ni and Cu.
Numerical study of turnstile operation in random-multidot-channel field-effect transistor
Authors: Ikeda Hiroya , Tabe Michiharu
Published: April 2006

We have numerically studied the single-charge transfer operation in two-dimensional (2D) random-multidot-channel field-effect transistors (FETs) using orthodox theory of the Coulomb blockade phenomenon. The randomness of the multidot structure is reflected in the gate capacitance (Cg) in the equivalent circuit, embodying the dot-size disorder of the realistic devices developed in our laboratory. It was found that “turnstile operation” meaning that individual electron is transferred one by one from the source to the drain with a cycle of an alternating gate voltage can be performed in both random and homogeneous 2D multidot-channel FETs, although their equivalent circuits are significantly different from the ordinary four-junction turnstile device. By increasing the Cg randomness, some devices show that the average gate and drain bias condition (Vg0,Vd) which allows the turnstile operation is more relaxed. Consequently, the random-multidot-channel FET can work as a single-electron turnstile device.
Normal modes and birefringent magnetophotonic crystals
Authors: Levy Miguel
Published: April 2006

A theoretical model for single-defect one-dimensional magnetic photonic crystals with combined linear and circular birefringences is presented. The model elucidates the polarization response of waveguide magnetophotonic crystals and predicts a spectrally asymmetric transmittance detuning from the Bragg frequency. The key components of the model are (a) the presence of two orthogonal elliptically polarized normal modes propagating at different speeds and (b) resonant transmission of these modes through the photonic crystal. Analytical expressions for the normal mode vector field amplitudes and their transmittance through the photonic crystal are obtained. The model predicts a significant nonreciprocal rotation in the presence of linear birefringence levels that would normally suppress the Faraday rotation in ordinary optical channels. Agreement is found with transfer matrix simulation predictions.
New model for ultracompact coaxial Marx pulse generator simulations
Authors: Martin Benoît , Raymond Pierre , Wey Joseph
Published: April 2006

This article describes a new simulation model developed with PSPICE in order to improve the ultra compact Marx generators designed at the French-German Research Institute of Saint-Louis (ISL). The proposed model is based on a Marx elementary unit and is an equivalent electric circuit that matches the actual configuration of the generator. It consists of a structural description of the elementary stage of a Marx generator including stray components. It also includes a behavioral model of the spark gap switches based on the Vlastos formula determining the arc resistance value. The prebreakdown delay is also taken into account. Experimental data have been used to validate the results of the simulations. An original indirect measurement, allowing the estimation of the spark gap resistance, is also proposed.
Dielectric SiO2∕ZrO2 distributed Bragg reflectors for ZnO microcavities prepared by the reactive helicon-wave-excited-plasma sputtering method
Authors: Chichibu S. F. , Ohmori T. , Shibata N. , Koyama T.
Published: April 2006

Reactive helicon-wave-excited-plasma sputtering method is shown to be a suitable technique for the fabrication of high reflectivity (R) distributed Bragg reflectors (DBRs), in particular, operating at the resonance wavelength of B excitons in ZnO (366.5nm), utilizing quarter-wavelength multilayers of SiO2 and ZrO2 dielectric films. According to the surface-damage-free nature and proper stoichiometry controllability of the method, dense dielectric films exhibiting ideal refractive indices (1.46 for SiO2 and 2.10 for ZrO2 at 633nm) and small root-mean-square values for the surface roughness (0.20nm for SiO2 and 0.53nm for ZrO2) were deposited using Si and Zr targets and O2 gas at room temperature. Optical reflectance spectra of the SiO2∕ZrO2 DBRs agreed with those calculated using the optical multilayer film theory, and eight-pair DBR exhibited R higher than 99.5% at 366.5nm and 82nm stop bandwidth (R⩾95%). The results indicate that the DBR can be used for the realization of polariton lasers using ZnO microcavities.
A case of Henoch–Schonlein purpura temporarily improved by hemodialysis
Authors: TSUBOI Hiromi , TAKEMURA Tosiyuki , KATSUOKA Kensei
Published: April 2006

We report a case of Henoch–Schonlein purpura that occurred in an adult patient with end‐stage renal disease on continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD). The patient's skin lesions clearly decreased in number during HD, but not during CAPD. This finding has not been previously reported.
Sporothrix schenckii type 3D (mtDNA‐RFLP): Report of an osteoarticular case
Authors: CAMPOS‐MACÍAS Pablo , ARENAS Roberto , VEGA‐MEMIJE ME , KAWASAKI Masako
Published: April 2006

Sporotrichosis is a frequent subcutaneous mycosis in Mexico and lymphocutaneous cases are the most common type. Extracutaneous or disseminated forms are exceptional and are usually seen in immunosuppressed hosts. We report the case of a 74‐year‐old immunocompetent male with osteoarticular involvement. The isolated Sporothrix schenckii was classified as type 3D according to restriction fragment length polymorphism analysis of the mitochondrial DNA (mtDNA‐RFLP).
Determination of the Inflammatory Potential of Bioaerosols from a Duck‐Fattening Unit by Using a Limulus Amebocyte Lysate Assay and Human Whole Blood Cytokine Response
Authors: Zucker B.‐A. , Scharf P. , Kersten C.
Published: April 2006

Inhalation of bioaerosols from animal houses can induce acute inflammatory reactions in the respiratory tract. Determination of the concentration of airborne endotoxins is widely used to characterize this risk. In this study, the activity of bioaerosol samples from a duck‐fattening unit to induce interleukin‐1β (IL‐1β) in human blood and to react with Limulus Amebocyte Lysate (LAL) was investigated. The activity detected in the whole blood assay correlated well with the endotoxic activity found in the LAL assay (Spearmen's ρ = 0.902). However in all samples, the inflammation‐inducing potential was overestimated by the LAL assay. It is assumed that this overestimation could be, in part, a result of an overestimation of the inflammatory potential of endotoxins originating from Pseudomonadaceae by the LAL assay. Pseudomonadaceae were regularly isolated from the air of the duck‐fattening unit. The results presented here indicate that the whole blood assay can be used besides the LAL assay as an additional method to characterize the inflammation‐inducing potential of bioaerosols.
The white potato cyst nematode (Globodera pallida) – a critical analysis of the threat in Britain
Authors: TRUDGILL D L , ELLIOTT M J , EVANS K , PHILLIPS M S
Published: April 2006

Over the last 30 years, there has been an epidemic of the white potato cyst nematode (wPCN, Globodera pallida). It has progressively replaced the yellow species (yPCN, G. rostochiensis) throughout most of England and Wales and is now a widespread problem. As damaging populations of wPCN are enormous (>109 eggs ha−1), several crops of potato cultivars resistant only to yPCN were required to produce this change. The threat it poses is reflected in an increase in the numbers of soil samples being tested and in nematicide use, which has increased to > 25 000 ha of potatoes being treated annually. Computer modelling shows that current management of wPCN is mostly ineffective and populations will continue to increase. The multiplication rate of wPCN is inversely related to its population density at planting and, because of this, modelling shows that sufficient eggs are likely to survive to enable large populations of wPCN to “rebound” following nematicide treatment. This is supported by recent trial results showing that wPCN population increase was almost as great in nematicides‐treated plots as in the untreated. Modelling also showed that current rotations (typically potatoes once every 5 or 6 years) are too short to prevent wPCN populations from progressively increasing, even when used in conjunction with a nematicide. Similarly, except with avirulent populations, the partially resistant cultivars currently available will not prevent wPCN from increasing. However, as the effectiveness of partially resistant cultivars is independent of population density, they can be very effective when integrated with a nematicide. Unfortunately, only c. 8% of the potato area is planted with partially resistant cultivars, and much of that is in land not known to be infested with wPCN. Consequently, the current epidemic of wPCN is likely to become progressively more serious. However, many farmers are failing to recognise and respond to this threat until it is too late because of the slow rate of increase of wPCN, the difficulties of detecting small populations and the costs of nematicides. To respond to the current epidemic of wPCN, the greatest priority is to have available an increased number of commercially‐attractive partially resistant cultivars.
EXPLORING TWO INFLATIONARY REGIMES IN LATIN-AMERICAN ECONOMIES: A BINARY TIME SERIES ANALYSIS
Authors: BRIDA JUAN GABRIEL , GARRIDO NICOLAS
Published: April 2006

The aim of this paper is to apply the methods of Symbolic Time Series Analysis (STSA) to a series of inflation from a group of Latin-American economies. Starting with a partition of two inflation regimes, we use data symbolization for identifying temporal patterns. Afterwards the statistical information obtained from the patterns is used to estimate the parameters of a nonlinear model proposed by Brida (2000).1We compare the performance of the model against a naive benchmark predictor to verify its power to anticipate the qualitative behavior of the inflation time series. When the use of STSA is made through pure optimization criteria, the performance of the model is poor. However, when the partition of the space of states is made according to economics intuition, the performance of the model increases considerably.
PREDICTION IN HEALTH DOMAIN USING BAYESIAN NETWORKS OPTIMIZATION BASED ON INDUCTION LEARNING TECHNIQUES
Authors: FELGAER PABLO , BRITOS PAOLA , GARCÍA-MARTÍNEZ RAMÓN
Published: April 2006

A Bayesian network is a directed acyclic graph in which each node represents a variable and each arc a probabilistic dependency; they are used to provide: a compact form to represent the knowledge and flexible methods of reasoning. Obtaining it from data is a learning process that is divided in two steps: structural learning and parametric learning. In this paper we define an automatic learning method that optimizes the Bayesian networks applied to classification, using a hybrid method of learning that combines the advantages of the induction techniques of the decision trees (TDIDT-C4.5) with those of the Bayesian networks. The resulting method is applied to prediction in health domain.
INVESTIGATION ON THE MICROSCOPIC STRUCTURE OF E′δ CENTER IN AMORPHOUS SILICON DIOXIDE BY ELECTRON PARAMAGNETIC RESONANCE SPECTROSCOPY
Authors: BUSCARINO G. , AGNELLO S. , GELARDI F. M.
Published: April 2006

The E′δ center is one of the most important paramagnetic point defects in amorphous silicon dioxide ( a-SiO 2) primarily for applications in the field of electronics. In fact, its appearance in the gate oxide of metal-oxide-semiconductor (MOS) structures seriously affects the proper work of many devices and, often, causes their definitive failure. In spite of its relevance, until now a definitive microscopic model of this point defect has not been established. In the present work we review our experimental investigation by electron paramagnetic resonance (EPR) on the E′δ center induced in γ-ray irradiated a-SiO 2. This study has driven us to the determination of the intensity ratio between the hyperfine doublet and the main resonance line of this point defect. On the basis of this estimation we have pointed out that the unpaired electron wave function of the E′δ center is actually delocalized over four nearly equivalent silicon atoms, shedding new light on the microscopic structure of this technologically relevant point defect.
Mesenchymal cells from adult kidney support angiogenesis and differentiate into multiple interstitial cell types including erythropoietin-producing fibroblasts
Authors: Plotkin Matthew D. , Goligorsky Michael S.
Published: April 2006

Mesenchymal cells have been isolated from embryos and multiple adult organs where they may differentiate into various connective tissue cell types and provide paracrine support for surrounding cells. With the use of a technique for culturing multipotent mesenchymal cells from adult tissues, a fibroblast-like cell clone (4E) was isolated from adult mouse kidney. 4E cells were able to differentiate along multiple mesodermal lineages including cell types located in the renal interstitium such as fibroblasts and pericytes. Coculture of 4E cells with ureteric bud and epithelial cell lines and analysis of resulting changes in gene expression revealed that these cells support angiogenesis and tubulogenesis and expressed genes characteristic of embryonic renal stromal cells. Following subcapsular injection after unilateral ischemia-reperfusion in adult mice, 4E cells migrated to a peritubular interstitial location and expressed interstitial cell markers, whereas cells injected in control kidneys remained stationary. Incubation in hypoxic or anoxic conditions resulted in erythropoietin expression in a small subset of ecto-5′-nucleotidase-positive cells and resulted in increased vascular endothelial growth factor expression in the same cell population. Our findings suggest that the adult kidney may contain interstitial mesenchymal cell progenitors with embryonic stromal cell characteristics that are able to provide paracrine support for surrounding vessels and tubular epithelial cells and differentiate into erythropoietin producing fibroblasts.
Synthesis and Thermolysis of Tetracoordinate 1,2-Oxaphosphetanes Stabilized by Steric Protection
Authors: Kawashima Takayuki , Takami Hiromichi , Okazaki Renji
Published: April 2006

The title compounds bearing a 2,4,6-triisopropylphenyl group stable in air at room temperature were synthesized in good yields by intramolecular dehydration of the corresponding β-hydroxy phosphinic acids. Thermolysis gave the corresponding olefin along with ring-opening products. Selectivity of olefin formation depends on additives.
Very Convenient and Efficient Purification Method for Fullerene (C60) with 5,11,17,23,29,35,41,47-Octa-tert-butylcalix[8]arene-49,50,51,52,53,54,55,56-octol
Authors: Suzuki Tsuyoshi , Nakashima Kazuaki , Shinkai Seiji
Published: April 2006

The gram-order of fullerene (C60) with 99.8 wt% purity was isolated from carbon soot by fractional precipitation with 5,11,17,23,29,35,41,47-octa-tert-butylcalix[8]arene-49,50,51,52,53,54,55,56-octol. This is a very convenient and efficient C60 purification method without any precious apparatus.
Extreme Weather Trends Vs. Dangerous Climate Change: A Need for Critical Reassessment
Authors: Khandekar Madhav L
Published: April 2006

The ongoing debate on global warming and increasing concentration of atmospheric greenhouse gases (CO2 in particular) highlights the possibility of increased incidences of extreme weather events world-wide, as the earth's mean temperature is expected to rise steadily in future. Several recent technical and scientific conferences have focused on the general theme of “dangerous climate change” and on avoiding or reducing this danger. However, a careful analysis of observed data on world-wide extreme weather events does not reveal any increasing trend in these events, thus suggesting a mismatch between reality and the hypothesis of dangerous climate change. There is a definite need to critically re-examine the hypothesis of dangerous climate change in the context of observed trend (or lack of it) in the extreme weather events worldwide.