bluuebunny/crossref_metadata_2025 huggingface dataset:
A new configuration of multi-wavelength Brillouin fiber laser
Authors: Harun S W , Shirazi M R , Ahmad H
Published: July 2007

A multi-wavelength laser is demonstrated using stimulated Brillouin scattering in a single-mode fiber with a feedback loop using two couplers and an optical circulator. This Brillouin fiber laser can operate at any wavelength depending on the Brillouin pump (BP) wavelength used. With a BP of 14 dBm, approximately 8 to 10 BFL lines are obtained in both forward and backward directions respectively with a line spacing of 0.16 nm. The use of the 99/1 coupler and 50/50 coupler gives the highest power and number of lines for the forward and backward outputs respectively. The maximum Stokes power obtained is approximately 8.0 dBm. The anti-Stokes lines are also obtained due to four wave mixing and bidirectional operation. The combination of forward and backward output can generate a larger number of lines with channel spacing of 0.08 nm.
Stereocomplex formation between enantiomeric poly(α‐methyl‐α‐ethyl‐β‐propiolactones): Effect of molecular weight
Authors: Fraschini Carole , Pennors Anne , Prud'homme Robert E.
Published: July 2007

Optically pure S(−) and R(+)‐poly(α‐methyl‐α‐ethyl‐β‐propiolactones) (PMEPLs) of controlled low molecular weights were synthesized by anionic polymerization of the corresponding optically active monomers, and characterized using gel permeation chromatography, Maldi‐TOF mass spectrometry, and NMR spectroscopy. Blends of PMEPLs of opposite configurations and different molecular weights were investigated. All blends lead to the formation of a stereocomplex and its crystallization prevails over a wide range of mixing ratios. The stereocomplex melts 30–40 °C above that of the corresponding pure polymers, depending on the molecular weight; pairs of polymers having similar molecular weights exhibit the highest melting temperatures and enthalpies of fusion. Finally, when the stereocomplex is dispersed in a PMEPL matrix, it acts as a very effective nucleation agent for the crystallization of the polymer in excess. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2380–2389, 2007
Case for diagnosis: 4‐month‐old infant with increasing cough, hemoptysis, and anemia
Authors: Snijders D. , Stenghele C. , Monciotti C. , Piccolo R. Lo , Alaggio R. , Zanon G.F. , Barbato A.
Published: July 2007

A 4‐month‐old caucasian infant presented non‐productive cough, fever associated with hemoptysis, and increasing anemia. He had mild tachypnoea; routine lab tests were normal. The thoracic HRCT scan showed a very large mass in the right lung adherent to the thorax wall, well defined and limiting the medium and upper lobe; the mass was well vascularized, and with central hypodensic areas. Fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) cytology were normal. The definitive histology of the mass showed the presence of inflammatory cells admixed with fibroblasts and rare Touton giant cells in the lesion suggestive of a juvenile xanthogranuloma (JXG) of the lung. Pediatr Pulmonol. 2007; 42:844–846. © 2007 Wiley‐Liss, Inc.
Approach to eradication of initial Pseudomonas aeruginosa infection in children with cystic fibrosis
Authors: Treggiari Miriam M. , Rosenfeld Margaret , Retsch‐Bogart George , Gibson Ron , Ramsey Bonnie
Published: July 2007

The primary cause of morbidity and mortality in children with cystic fibrosis (CF) is the progression of obstructive lung disease secondary to chronic endobronchial infection, mainly caused by Pseudomonas aeruginosa (Pa). Initial Pa isolates are typically non‐mucoid, usually susceptible to most anti‐pseudomonal antibiotics, and potentially amenable to eradication. Preliminary studies of early intervention suggest a “window of opportunity” with anti‐pseudomonal antibiotics to eradicate Pa from upper and lower airways. Several large trials in young children with CF are currently ongoing with the goals of (1) investigating if early intervention at the time of initial Pa acquisition is effective and safe and (2) identifying the least invasive and safest treatment regimen to achieve both microbiologic and clinical benefits. Pediatr Pulmonol. 2007; 42:751–756. © 2007 Wiley‐Liss, Inc.
Achieving Quality and Outcome Framework glycaemia targets
Authors: Farooqi Azhar
Published: July 2007

Glycosylated haemoglobin levels are a key monitoring tool for diabetes control and the basis for targets in the QOF for diabetes. The first article in this occasional series discusses how the targets are best achieved in various patient groups. Copyright © 2007 Wiley Interface Ltd
Radiative transition probabilities of CO2+
Authors: Šedivcová‐Uhlíková Tereza , Kaprálová‐Žďánská Petra R. , Špirko Vladimír
Published: July 2007

Radiative transition probabilities (Einstein A coefficients), Franck‐Condon factors, and radiative lifetimes have been determined for the X3Π, 3Σ−, a1Σ+, 1Π, c1 Δ, and A3Σ+ states of the CO2+ dication using ab initio potential energy, spin‐orbit coupling, electric dipole and electronic transition moment functions, and the standard complex‐scaling method. The calculated radiative lifetimes of the upper electronic states of the spin‐allowed A3Σ+–X3Π and b1Π–a1Σ+ transitions are generally longer than their predissociating lifetimes, explaining thus the failure of the attempts made so far to observe CO2+ in the optical spectral region in a convincing fashion. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Analysis of 25 underivatized amino acids in human plasma using ion‐pairing reversed‐phase liquid chromatography/time‐of‐flight mass spectrometry
Authors: Armstrong Michael , Jonscher Karen , Reisdorph Nichole A.
Published: July 2007

Amino acids in biological fluids have previously been shown to be detectable using liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) with perfluorinated acids as ion‐pairing agents. To date, these studies have used precursor mass, retention time and tandem mass spectrometry (MS/MS) to identify and quantify amino acids. While this is a potentially powerful technique, we sought to adapt the method to time‐of‐flight (TOF)MS. A new application of a recently described liquid chromatographic separation method was coupled with TOFMS to employ accurate mass for qualitative identification; resulting in additional qualitative data not available with standard single quadrupole data. In the current study, we evaluated 25 physiological amino acids and one dipeptide that are routinely quantified in human plasma. Accuracy and precision of the method was evaluated by spiking human plasma with a mix of the 25 amino acids; in addition, the inclusion of a cation‐exchange cleanup step was evaluated. The calibration curves were linear over a range from 1.56 to 400 µM. The dynamic range was found to be within physiological levels for all amino acids analyzed. Accuracy and precision for most of the amino acids was between 80–120% spike recovery and <10% relative standard deviation (RSD). The LC/MS technique described in this study relies on mass accuracy and is suitable for the quantitation of free amino acids in plasma. Copyright © 2007 John Wiley & Sons, Ltd.
Three‐dimensional transperineal sonographic characteristics of the anal sphincter complex in nulliparous women
Authors: Huang W.‐C. , Yang S.‐H. , Yang J.‐M.
Published: July 2007

Objective

To explore the morphological characteristics and normal biometry of the anal sphincter complex in nulliparous Chinese women using three‐dimensional (3D) transperineal ultrasound.

Methods

3D sonographic data from 55 nulliparous Chinese women (aged 19–38 years) who had no pelvic organ prolapse and no symptoms of pelvic floor dysfunction were retrieved from an image dataset and analyzed by offline post‐processing. The morphological characteristics of the external and internal anal sphincters, puborectalis muscle and perineal body were assessed in the sagittal, coronal and axial views.

Results

The external anal sphincter had three sonographic components: the circular main body, a subcutaneous part and an extension portion. It was significantly thinner at 12 o'clock than at the 3, 6 and 9 o'clock positions. The internal anal sphincter was seen as dark echolucent strips of equal thickness. In the mid‐sagittal view, it started from the anal verge and ended at the anorectal junction. The perineal body was an ovoid structure covering the upper margin of the external sphincter, while the puborectalis muscle was banana‐shaped in the sagittal view and was located behind the anorectal junction, extending downward along the inferior margin of the posterior external sphincter extension. Sonographic characteristics of the anal sphincter complex did not vary with age, weight, height or body mass index.

Conclusions

3D transperineal ultrasound clearly demonstrates the spatial relationships of each component of the anal sphincter complex. This should allow standardized measurement of the complex for investigations of its function. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Seed dispersal of Korean pine Pinus koraiensis labeled by two different tags in a northern temperate forest, northeast China
Authors: Yi Xianfeng , Xiao Zhishu , Zhang Zhibin
Published: July 2007

Two types of tagging methods, i.e., a 1 × 3‐cm tin tag attached to seed with a 10‐ to 12‐cm metal wire (total weight 0.32 g) and a 2 × 4‐cm white plastic tag fastened to seed with an identical metal wire (total weight 0.57 g) were used to study their effects on seed dispersal of Korean pine by small rodents. A total of 600 seeds were released to assess four main points: (1) difference in seed survival rates, (2) difference in caching behaviors of small rodents, (3) difference in dispersal distances, and (4) proportion of seed missing. The results demonstrated that seed removal for wire‐plastic‐tagged seeds was faster than that for wire‐tin‐tagged seeds. There was no apparent difference in the proportion of seeds eaten in situ (42% and 52% for wire‐plastic‐tagged seeds and wire‐tin‐tagged seeds, respectively). We found 41% and 1% of seeds were moved and hoarded for wire‐plastic‐tagged seeds and wire‐tin‐tagged seeds, respectively. However, 2.33% and 14% of seeds were missing, and their ultimate fates were not known for wire‐plastic‐tagged seeds and wire‐tin‐tagged seeds, respectively. We found the wire‐plastic‐tagged seeds easier to track than the wire‐tin‐tagged seeds due to the fact that the white plastic tags were more salient than the tin tags in field environments. The average dispersal distances were 4.11 ± 2.40 m and 3.01 ± 2.06 m for wire‐plastic‐tagged seeds and wire‐tin‐tagged seeds, respectively, and showed great difference. Despite most being eaten in situ or after removal, 41% of seeds were cached for wire‐plastic‐tagged seeds, much more than for wire‐tin‐tagged seeds. A total of 71 primary caches (123 seeds) were found for wire‐plastic‐tagged seeds, with the average and maximum cache sizes being 1.73 and 6, respectively. However, only three caches were found, and cache size was equal to one for wire‐tin‐tagged seeds. The above data suggests there is some uncertainty in different tagging methods to used track seed fates. Despite their effectiveness in helping to trace seed dispersal or movement by seed‐dispersing rodents, different tagging methods—including size, color, and mass—need to be fully understand in enclosure experiments

.
Effects of Dietary Cholesterol on Tissue Ceramides and Oxidation Products of Apolipoprotein B‐100 in ApoE‐Deficient Mice
Authors: Ichi Ikuyo , Takashima Yuka , Adachi Noriko , Nakahara Kayoko , Kamikawa Chiaki , Harada‐Shiba Mariko , Kojo Shosuke
Published: July 2007

Oxidized LDL (oxLDL) has been shown to activate the sphingomyelinase pathway producing ceramide in vascular smooth muscle cells. Therefore ceramide, which is a biologically active lipid causing apoptosis in a variety of cells, may be involved in the apoptotic action of oxLDL. In this study, we examined whether cholesterol enriched diets affected ceramide metabolism and oxidation product of LDL, represented by degradation of apolipoprotein B‐100 (apoB) in apoE‐deficient (apoE−/−) mice. ApoE−/− and wild type mice were fed a standard (AIN‐76) diet or 1% cholesterol‐enriched diet for 8 weeks. Tissue ceramide levels were analyzed using electrospray tandem mass spectrometry (LC‐MS/MS). Ceramide levels in the plasma and the liver of apoE−/− mice were intrinsically higher than those of the wild type. In apoE−/− mice, dietary cholesterol significantly increased several ceramides and degradation products of apoB in plasma compared to those fed the control diet. Dietary cholesterol did not affect tissue ceramide levels in the wild type mice. Based on these results, plasma ceramides possibly correlate with the increase in LDL oxidation and are a risk factor for atherosclerosis.
Dietary Counseling and Probiotic Supplementation During Pregnancy Modify Placental Phospholipid Fatty Acids
Authors: Kaplas Niina , Isolauri Erika , Lampi Anna‐Maija , Ojala Tiina , Laitinen Kirsi
Published: July 2007

It has previously been shown that maternal nutrition affects the fetal environment, with consequences for the infant's health. From early pregnancy onwards participants here received a combination of dietary counseling and probiotics (Lactobacillus GG and Bifidobacterium lactis Bb12; n = 10), dietary counseling with placebo (n = 12), or placebo alone (n = 8). The major differences in placental fatty acids were attributable to a higher concentration of n‐3 polyunsaturated fatty acids in both intervention arms than in controls. Further, dietary counseling with probiotics resulted in higher concentrations of linoleic (18:2n‐6) and dihomo‐γ‐linolenic acids (20:3n‐6) compared with dietary counseling with placebo or controls.
Morse index properties of colliding solutions to the N-body problem
Authors: Secchi Simone , Barutello Vivina
Published: July 2007

We study a singular Hamiltonian system with an

α

-homogeneous potential that contains, as a particular case, the classical

N

-body problem. We introduce a variational Morse-like index for a class of collision solutions and, using the asymptotic estimates near collisions, we prove the non-minimality of some special classes of colliding trajectories under suitable spectral conditions provided

α

is sufficiently away from zero. We then prove some minimality results for small values of the parameter

α

.

Nous étudions un système dynamique de type hamiltonien avec un potentiel

α

-omogène et singulier. Nous introduisons un indice variationnel de type Morse pour une classe de solutions avec collision et, à l'aide de certaines estimations asymptotiques dans un entourage des collisions, nous prouvons des resultats de non-minimalité lorsque

α

ne devient pas trop petit, sous des hypothèses spectrales. Enfin, nous prouvons aussi un résultat de minimalité lorsque

\alpha \rightarrow 0

.
Where do animal α‐amylases come from? An interkingdom trip
Authors: Da Lage Jean-Luc , Danchin Etienne G.J. , Casane Didier
Published: July 2007

Alpha‐amylases are widely found in eukaryotes and prokaryotes. Few amino acids are conserved among these organisms, but at an intra‐kingdom level, conserved protein domains exist. In animals, numerous conserved stretches are considered as typical of animal α‐amylases. Searching databases, we found no animal‐type α‐amylases outside the Bilateria. Instead, we found in the sponge Reniera sp. and in the sea anemone Nematostella vectensis, α‐amylases whose most similar cognate was that of the amoeba Dictyostelium discoideum. We found that this “Dictyo‐type” α‐amylase was shared not only by these non‐Bilaterian animals, but also by other Amoebozoa, Choanoflagellates, and Fungi. This suggested that the Dictyo‐type α‐amylase was present in the last common ancestor of Unikonts. The additional presence of the Dictyo‐type in some Ciliates and Excavates, suggests that horizontal gene transfers may have occurred among Eukaryotes. We have also detected putative interkingdom transfers of amylase genes, which obscured the historical reconstitution. Several alternative scenarii are discussed.
Do mitochondria act as “cargo boats” in the journey of GD3 to the nucleus during apoptosis?
Authors: Garofalo Tina , Tinari Antonella , Matarrese Paola , Giammarioli Anna Maria , Manganelli Valeria , Ciarlo Laura , Misasi Roberta , Sorice Maurizio , Malorni Walter
Published: July 2007

Plasma membrane lipid rafts have been considered as a sort of “chamber”, where several subcellular activities, including CD95/Fas‐mediated pro‐apoptotic signaling, can take place. Recently, we demonstrated that, after CD95/Fas triggering, raft‐like microdomains could be detected in mitochondrial membranes. The mitochondrion appears as a dynamic and subcompartmentalized organelle in which microdomains might act as controllers of apoptosis‐associated fission that results in the release of apoptogenic factors. Here, we hypothesize that some “small” mitochondria, possibly derived from their fission process, can reach the nuclear envelope and strictly interact with this. Mitochondria could act as a signaling “device” contributing to molecular trafficking of molecules, including raft‐like components, during apoptosis.
Upper mantle lateral inhomogeneity estimated using global MVS
Authors: Plotkin V.V. , Belinskaya A.Yu. , Gavrysh P.A.
Published: July 2007

We processed synchronous observatory MVS data at periods from 1.2 to 6 days to estimate lateral conductivity variations in the upper mantle. The inverse problem for depth-dependent conductivity distribution was solved using correlation of the measured surface components of the geomagnetic field. We applied spherical harmonic expansion of the complex amplitudes of time harmonics and multiple averaging of the amplitudes obtained for different SH sets. The chosen approximation approach was tested by comparing the EM field simulated for a smoothly inhomogeneous Earth with the exact forward solution. The SHA-analyzed observatory data for fifteen magnetic storms were used to map global apparent conductivity variations.
Relationship of the seismic activity of the Tuvinian and adjacent Mongolian areas with the fractal dimensionality of a fault system
Authors: Ayunova O.D. , Kalush Yu.A. , Loginov V.M.
Published: July 2007

Using GIS technologies, we carried out a complex spatial analysis of the seismic activity and fractal dimensionality of fault fields in the Tuvinian and adjacent Mongolian areas. Results obtained showed that seismic activity is intrinsic to zones with the low fractal dimensionalities (1.2–1.4) of fault systems.
Inverse solution to the wave equation using the Laguerre transform
Authors: Mastryukov A.F. , Mikhailenko B.G.
Published: July 2007

An inverse solution to the 1D wave equation is obtained using the spectral Laguerre transform to find the distribution of wave velocities at some point of the medium. The problem is solved as optimization in which the function of Laguerre harmonics is minimized by the conjugate gradient or Newton’s algorithms.

Reported are velocities of a wave defined by a stepwise constant function. The accuracy of the inverse solution for the Laguerre harmonics is investigated against the approximation accuracy in the boundary problem. The accuracy and efficiency of the Laguerre method are compared to those in the Fourier method.
Late Cenozoic fault pattern and stress fields in the Barguzin rift (Baikal region)
Authors: Lunina O.V. , Gladkov A.S.
Published: July 2007

New structural and tectonophysical data, combined with the published geophysical and seismological evidence, were used to map the Late Cenozoic fault pattern and crustal stress in the Barguzin rift. Faults striking in the NE direction are the most abundant elements of the rift structure. A special part in the Late Cenozoic patterns of faults and stresses belongs to an over 400 km long N-S lineament which shows up as a system of separate fault segments between 110° and 110°30′ E. The Late Cenozoic evolution of the rift has been controlled mainly by extension punctuated with local shear stresses derived from the regional extension stress and accommodated by strike slip, combined with the dominant normal motion, along NE or N-NE faults and/or along their cross faults. Extension was of a relatively stable NW-SE direction, almost rift-orthogonal. The obtained fault pattern and stress maps can be used for reference in mapping seismic hazard associated with ongoing faulting in an active and changeable stress field.
Gravity effects caused by moderate earthquakes: role of local fault pattern
Authors: Lunina O.V. , Radziminovich Ya.B. , Gladkov A.S.
Published: July 2007

A rockfall was discovered on the left bank of the Verkhnyaya Angara River, 25 km away from the northwestern doorway of the North Muya tunnel of the Baikal-Amur Railway. We investigate the tectonic position of the rockfall and its linkage to a moderate earthquake using structural data and show that earthquakes of this intensity can produce notable ground failure if the local fault pattern is favorable for passage of seismic waves.
Prehistoric earthquakes and fault scarps in the Barguzin fault zone (Baikal Rift system)
Authors: Chipizubov A.V. , Arzhannikov S.G. , Semenov R.M. , Smekalin O.P.
Published: July 2007

We studied fault scarps produced by prehistoric earthquakes in the Barguzin fault zone and estimated the ages and the magnitudes of the scarp-forming events in each scarp segment from their structure, morphology, and scarp parameters. Morphological and structural data reveal two to four surface-rupturing events with displacement up to 5–9.5 m, and two events showed 14C ages of 4.5 and 9 kyr. The area of the Barguzin Fault may have experienced six 7.5 ≤ M < 8.0 earthquakes and two M ≥ 8.0 (8.0–8.2) events for the past 10–12 kyr.
Nature and origin of a Pleistocene-age massive ground-ice body exposed in the Chapman Lake moraine Complex, central Yukon Territory, Canada
Authors: Lacelle Denis , Lauriol Bernard , Clark Ian D. , Cardyn Raphaelle , Zdanowicz Christian
Published: July 2007

A massive ground-ice body was found exposed in the headwall of a thaw flow developed within the Chapman Lake terminal moraine complex on the Blackstone Plateau (Ogilvie Mountains, central Yukon Territory), which is contemporaneous to the Reid glaciation. Based on visible cryostructures in the 4-m-high headwall, two units were identified: massive ground ice, overlain sharply by 2 m of icy diamicton. The nature and origin of the Chapman Lake massive ground ice was determined using cryostratigraphy, petrography, stable O–H isotopes and the molar concentration of occluded gases (CO2, O2, N2 and Ar) entrapped in the ice, a new technique in the field of periglacial geomorphology that allows to distinguish between glacial and non-glacial intrasedimental ice. Collectively, the results indicate that the Chapman Lake massive ground ice formed by firn densification with limited melting–refreezing and underwent deformation near its margin. Given that the massive ground-ice body consists of relict glacier ice, it suggests that permafrost persisted, at least locally, on plateau areas in the central Yukon Territory since the middle Pleistocene. In addition, the d value of Chapman Lake relict glacier ice suggests that the ice covering the area during the Reid glaciation originated from a local alpine glaciation in the Ogilvie Mountains.
Submarine hydrothermal activity along the mid‐Kermadec Arc, New Zealand: Large‐scale effects on venting
Authors: de Ronde C. E. J. , Baker E. T. , Massoth G. J. , Lupton J. E. , Wright I. C. , Sparks R. J. , Bannister S. C. , Reyners M. E. , Walker S. L. , Greene R. R. , Ishibashi J. , Faure K. , Resing J. A. , Lebon G. T.
Published: July 2007

The 2,500‐km Kermadec‐Tonga arc is the longest submarine arc on the planet. Here, we report on the second of a series of cruises designed to investigate large‐scale controls on active hydrothermal venting on this arc. The 2002 NZAPLUME II cruise surveyed 12 submarine volcanic centers along ∼580 km of the middle Kermadec arc (MKA), extending a 1999 cruise that surveyed 260 km of the southern Kermadec arc (SKA). Average spacing between volcanic centers increases northward from 30 km on backarc crust along the SKA, to 45 km on backarc crust along the southern MKA, to 58 km where the MKA joins the Kermadec Ridge. Volcanic cones dominate in the backarc, and calderas dominate the Kermadec Ridge. The incidence of venting is higher along the MKA (83%, 10 of 12 volcanic centers) than the SKA (67%, 8 of 12), but the relative intensity of venting, as given by plume thickness, areal extent, and concentration of dissolved gases and ionic species, is generally weaker in the MKA. This pattern may reflect subduction of the ∼17‐km‐thick oceanic Hikurangi Plateau beneath the SKA. Subduction of this basaltic mass should greatly increase fluid loss from the downgoing slab, initiating extensive melting in the upper mantle wedge and invigorating the hydrothermal systems of the SKA. Conversely, volcanic centers in the southern MKA are starved of magma replenishment and so their hydrothermal systems are waning. Farther north, where the MKA centers merge with the Kermadec Ridge, fewer but larger magma bodies accumulate in the thicker (older) crust, ensuring more widely separated, caldera‐dominated volcanic centers.
Observations of plasma depletions in 557.7‐nm images over Kavalur
Authors: Rajesh P. K. , Liu J. Y. , Sinha H. S. S. , Banerjee S. B. , Misra R. N. , Dutt N. , Dadhania M. B.
Published: July 2007

An all sky imaging system was operated at Kavalur (12.56°N, 78.8°E, 4.6°N, geomagnetic), India, during February‐April 2002. We observed plasma depletions in the 557.7‐ and 630.0‐nm images in several nights and found that in most of the nights, the 557.7‐nm depletions appeared around midnight and became very pronounced in the postmidnight hours. A simulation is carried out to understand the important physical parameters that influence the emissions of the 557.7 nm in various local times and solar activities, and that result in the appearance of depletions in the integrated images.
Why some alluvial rivers develop an anabranching pattern
Authors: Huang He Qing , Nanson Gerald C.
Published: July 2007

Anabranching rivers have been identified globally, but a widely accepted and convincing theoretical explanation for their occurrence has remained elusive. Using basic flow and sediment transport relations, this study analyzes the mechanisms whereby self‐adjusting alluvial channels can anabranch to alter their flow efficiency (sediment transport capacity per unit of stream power). It shows that without adjusting channel slope, an increase in the number of channels can produce a proportional decrease in flow efficiency, a finding particularly relevant to understanding energy consumption in some braided rivers. However, anabranching efficiency can be significantly increased by a reduction in channel width, as occurs when vegetated alluvial islands or between‐channel ridges form. The counteracting effects of width reduction and an increasing number of channels can cause, with no adjustment to slope, an otherwise unstable system (underloaded or overloaded) to achieve stability. As with other river patterns, anabranching can be characterized by stable equilibrium or accreting disequilibrium examples.
Accounting for lateral variations of the upper mantle gradient in Pn tomography studies
Authors: Phillips W. S. , Begnaud M. L. , Rowe C. A. , Steck L. K. , Myers S. C. , Pasyanos M. E. , Ballard S.
Published: July 2007

The effect of an upper mantle velocity gradient on regional arrival times has been approximated by a cubic distance term, which can be extended to two dimensions for use in tomographic studies. To demonstrate this, we add a laterally varying upper mantle gradient to the standard Pn time‐term tomography technique, and apply to a data set from Asia compiled using ground truth, event location criteria. We observe strong lateral variations in the gradient, ranging from −0.001 to 0.003 s−1, with high gradients associated with the Tethys convergence zone. The gradient patterns may reflect lateral variations in the thermal gradient of the mantle lid. Variance reduction is 63% with respect to Pn tomography without gradients. Adding gradients allows the use of longer path lengths, improving velocity image definition in high‐gradient regions with sparse station distribution, such as Tibet.
Longitudinal structure of the vertical E × B drift and ion density seen from ROCSAT‐1
Authors: Kil Hyosub , Oh S.‐J. , Kelley M. C. , Paxton L. J. , England S. L. , Talaat E. , Min K.‐W. , Su S.‐Y.
Published: July 2007

We investigate the longitudinal distribution of the vertical E × B drift velocity and ion density in the low‐latitude ionosphere using the first Republic of China Satellite (ROCSAT‐1) data acquired during 1999–2004. The ROCSAT‐1 observations during daytime demonstrate the presence of the longitudinally periodic patterns of the vertical E × B drift and plasma density on the topside F region (600 km). The four longitude sectors where the peaks in the plasma density are found are coincident with the peaks in the E × B drift. This observation may indicate the association of the large‐scale longitudinal density structure with the daytime E‐region dynamo electric field. The density structure exists before the occurrence of the pre‐reversal enhancement (PRE) and therefore the PRE is not directly related to this phenomenon.
Advanced lipid peroxidation end products in oxidative damage to proteins. Potential role in diseases and therapeutic prospects for the inhibitors
Authors: Negre‐Salvayre A , Coatrieux C , Ingueneau C , Salvayre R
Published: July 2007

Reactive carbonyl compounds (RCCs) formed during lipid peroxidation and sugar glycoxidation, namely Advanced lipid peroxidation end products (ALEs) and Advanced Glycation end products (AGEs), accumulate with ageing and oxidative stress‐related diseases, such as atherosclerosis, diabetes or neurodegenerative diseases. RCCs induce the ‘carbonyl stress’ characterized by the formation of adducts and cross‐links on proteins, which progressively leads to impaired protein function and damages in all tissues, and pathological consequences including cell dysfunction, inflammatory response and apoptosis. The prevention of carbonyl stress involves the use of free radical scavengers and antioxidants that prevent the generation of lipid peroxidation products, but are inefficient on pre‐formed RCCs. Conversely, carbonyl scavengers prevent carbonyl stress by inhibiting the formation of protein cross‐links. While a large variety of AGE inhibitors has been developed, only few carbonyl scavengers have been tested on ALE‐mediated effects. This review summarizes the signalling properties of ALEs and ALE‐precursors, their role in the pathogenesis of oxidative stress‐associated diseases, and the different agents efficient in neutralizing ALEs effectsin vitroandin vivo. The generation of drugs sharing both antioxidant and carbonyl scavenger properties represents a new therapeutic challenge in the treatment of carbonyl stress‐associated diseases.

British Journal of Pharmacology(2008)153, 6–20; doi:10.1038/sj.bjp.0707395; published online 23 July 2007
Fractal concepts and their applications to gels
Authors: COURTENS E.
Published: July 2007

Recent progress in the theory of fractal excitations, in the simulation of these excitations, and in experiments on fractal aerogels are reviewed. The paper is an extended abstract intended as a guide to the current literature.
Thin films and architectural glass
Authors: BUFFAT B.
Published: July 2007

The use of thin films in the flat glass industry is growing steadily. In this paper, after a brief description of the pyrolytic and magnetron sputtering deposition techniques, a survey is presented of the essential film designs which have been developped by glass manufacturers to improve their products in the field of architectural glazings.
Effet de formateur mixte sur la conductivité ionique des verres du système Ag2O-B2O3-TeO2
Authors: COPPO D. , DUCLOT M. J. , SOUQUET J. L.
Published: July 2007

The so-called mixed anion effect is a non linear enhancement for ionic conductivity with the composition. It is observed for alkali or silver conducting glasses when two different network formers are associated. We have synthetised glasses in the system 0.3 Ag2O-0.7 [x B2O3 (1-x) Te2O4] with [MATH]. From optical, X Ray, electronic microscopy observations, Tg and electrical conductivity measurements, these glasses seem homogeneous. Isothermal conductivity curves define two maxima near x = 0.25 and x = 0.75. The conductivity enhancement may reach one order of magnitude compared to a additive behavior. A thermodynamic approach is proposed and the two maxima for conductivity measurements are qualitatively explained by an enhancement of the partial free energy for the limiting compositions due to an endothermic mixture.
Vibrational dynamics and structural relaxation in aqueous electrolyte solutions in the liquid, undercooled liquid and glassy states
Authors: DUPUY J. , JAL J. F. , PRÉVEL B. , AOUIZERAT-ELARBY A. , CHIEUX P. , DIANOUX A. J. , LEGRAND J. F.
Published: July 2007

In very concentrated aqueous electrolyte solutions, the competition between dipolar and ionic forces and most of the system properties, are finely monitored by the concentration. For LiCl, RH2O (R being the number of water moles per mole of salt) two domains of concentration exist around even hydration numbers R = 6 and R = 4, which can be reversibly undercooled from the liquid to the glassy state. At other concentrations, for [MATH], metastability is achieved only in a restricted temperature range. The collective behaviour as well as individual atomic motions, have been studied by neutron inelastic scattering in the metastable state of LiCl, 6H2O and LiCl, 4H2O down to the glass transition. The study of the structural relaxation by neutron spin echo (NSE) allows us to show that the temperature dependence of the response of the system follows a scaling relation with a cross-over at a phase transition present in the liquid phase.
Influence of substrate doping and point defects on Al and Ga interdiffusion in AlSb/GaSb superlattice structures
Authors: Slotte J. , Gonzalez-Debs M. , Kuech T. F. , Cederberg J. G.
Published: July 2007

Positron annihilation spectroscopy has been used to investigate the role of vacancies in the interdiffusion of Al and Ga in AlSb/GaSb superlattices. The samples were grown by metalorganic vapor-phase epitaxy on undoped and Te doped GaSb and consisted of ten periods of GaSb quantum wells (thickness 13 nm) and AlSb barriers (thickness 2–3 nm) and an approximately 50 nm thick capping layer of GaSb. The superlattices were annealed at 908 K for up to 250 s, resulting in interdiffusion of Al and Ga between well and barrier. A secondary ion mass spectrometry study showed that the Te dopant diffused from the substrate through the superlattice structure in the annealing process. In the positron annihilation study we observe that the vacancy concentration clearly decreases with annealing for the samples grown on undoped substrates, whereas the samples grown on Te doped substrates show a different annealing behavior.
Extraction of configurational entropy from molecular simulations via an expansion approximation
Authors: Killian Benjamin J. , Yundenfreund Kravitz Joslyn , Gilson Michael K.
Published: July 2007

A method is presented for extracting the configurational entropy of solute molecules from molecular dynamics simulations, in which the entropy is computed as an expansion of multidimensional mutual information terms, which account for correlated motions among the various internal degrees of freedom of the molecule. The mutual information expansion is demonstrated to be equivalent to estimating the full-dimensional configurational probability density function (PDF) using the generalized Kirkwood superposition approximation (GKSA). While the mutual information expansion is derived to the full dimensionality of the molecule, the current application uses a truncated form of the expansion in which all fourth- and higher-order mutual information terms are neglected. Truncation of the mutual information expansion at the nth order is shown to be equivalent to approximating the full-dimensional PDF using joint PDFs with dimensionality of n or smaller by successive application of the GKSA. The expansion method is used to compute the absolute (classical) configurational entropy in a basis of bond-angle-torsion internal coordinates for several small molecules as well as the change in entropy upon binding for a small host-guest system. Convergence properties of the computed entropy values as a function of simulation time are investigated and comparisons are made with entropy values from the second generation Mining Minima software. These comparisons demonstrate a deviation in −TS of no more than about 2kcal∕mol for all cases in which convergence has been obtained.
Numerical study of screech generation in a planar supersonic jet
Authors: Berland Julien , Bogey Christophe , Bailly Christophe
Published: July 2007

The generation of screech tones in an underexpanded jet is investigated by means of compressible large eddy simulation (LES). A three-dimensional planar geometry is considered with the aim of studying screech radiation in a simple jet configuration, whose physics nevertheless remains similar to that of large-aspect-ratio rectangular jets encountered in experimental surveys. The jet operates at fully expanded Mach number Mj=1.55, with Reynolds number Reh=6×104. The LES strategy is based on explicit selective filtering with spectral-like resolution, and low-dispersion and low-dissipation numerical algorithms are implemented to allow the direct noise computation of the phenomenon. The numerical results are first set against experimental data to establish the consistency of the simulation. It is shown that the flow development and the shock-cell structure are in agreement with experiments of the literature. Furthermore, the upstream acoustic field exhibit harmonic tones that compare correctly to screech tones observed on rectangular jets in terms of frequency, amplitude, and phase shift on either side of the jet. The extrapolation of the LES near-field data to the far field demonstrates that the radiated noise includes the three characteristic noise sources of supersonic shock-containing jets: screech tones, shock-associated noise, and mixing noise, with frequencies and directivities in agreement with experimental observations. Flow visualization of shock/vortex interactions near the third shock-cell finally provides evidences that screech sound sources can be interpreted using the shock-leakage theory. It is shown in particular that the third compression shock within the jet can leak outside through regions of the shear layer with low level of vorticity and results in the production of upstream-propagating sound waves contributing to screech tone radiation.
Inelastic collisions of cold polar molecules in nonparallel electric and magnetic fields
Authors: Abrahamsson E. , Tscherbul T. V. , Krems R. V.
Published: July 2007

The authors present a detailed study of low-temperature collisions between CaD molecules and He atoms in superimposed electric and magnetic fields with arbitrary orientations. Electric fields do not interact with the electron spin of the molecules directly but modify their rotational structure and, consequently, the spin-rotation interactions. The authors examine molecular Stark and Zeeman energy levels as functions of the angle between the fields and show that rotating fields may induce and shift avoided crossings between the Zeeman levels of the rotationally ground and rotationally excited states of the molecule. The dynamics of molecular collisions are extremely sensitive to external fields near these avoided crossings and it is shown that molecular collisions may be controlled by varying both the strength and the relative orientation of the fields. The effects observed in this study are due to interactions of the isolated molecules with external fields so the conclusions should be relevant for collisions of molecules with other atoms or collisions of molecules with each other. This study demonstrates that electric fields may be used to enhance or suppress spin-rotation interactions in molecules. The spin-rotation interactions induce nonadiabatic couplings between states of different total spins in systems of two open-shell species and it is suggested that electric fields might be used for controlling nonadiabatic spin transitions and spin-forbidden chemical reactions of cold molecules in a magnetic trap.
Small-scale anisotropy in magnetohydrodynamic turbulence under a strong uniform magnetic field
Authors: Ishida Takaki , Kaneda Yukio
Published: July 2007

Small-scale statistics in magnetohydrodynamic turbulence under an externally applied strong stationary uniform magnetic field is studied theoretically and numerically. A simple expression for the velocity correlation spectrum is derived by applying the idea of the perturbation method by Ishihara et al. [Phys. Rev. Lett. 88 154501 (2002)]. It gives not only the scale dependence but also the angular dependence of the anisotropic velocity correlation spectrum at small scales. It is in good agreement with direct numerical simulation with 5123 grid points.
Nucleation of chemical waves at defects: A mirror electron microscopy study of catalytic CO oxidation on Pt(110)
Authors: Wei Han , Lilienkamp G. , Imbihl R.
Published: July 2007

Using mirror electron microscopy (MEM) as spatially resolving method the nucleation of chemical waves in catalytic CO oxidation on a Pt(110) surface was investigated in the 10−5mbar range. The waves nucleated at an electrically insulating impurity of approximately 15μm diameter (the “defect”) which most likely represents a diamond particle left over from the polishing process. Nucleation events are initiated by a dynamic process in a boundary layer of approximately 1μm width between the defect and the surrounding Pt(110) surface. Depending on the parameter choice the fronts/pulses do not escape from the vicinity of the defect and later on die out or, in a supercritical nucleation, propagate across the surface. Asymmetric nucleation leads to spiral waves which remain pinned to the defect. The defect has a kind of steering effect causing chemical waves to collide exactly at the defect. This steering effect is evidently due to a distortion of the substrate lattice in the vicinity of the defect.
Selective photodissociation of O–H and O–D bonds from ground vibrational state of HOD using simple UV pulses
Authors: Sarma Manabendra , Adhikari S. , Mishra Manoj K.
Published: July 2007

Selective cleaving of both O–H and O–D bonds in HOD is achieved using reasonably simple UV pulses to excite the HOD molecule in its ground vibrational state to the repulsive first excited Ã(B11) surface. Detailed theoretical analysis of population transfer and flux in theH+O–D∕H–O+D channels reveals an important preparatory role for the cross-talk between the participating levels and a possible role for the beat structure of the population transfer oscillations in facilitating selective dissociation. Excitation using a 50fs single color 67169cm−1 laserpulse achieves a branching ratio H+O–D∕H–O+D=5.64 with 82% flux in theH+O–D channel and 15% in the H–O+D channel. A two color 50fs laser pulse with frequencies of 54 920 and 52303cm−1 provides a branching ratio of H–O+D∕H+O–D=2.83 and 52% flux in the H–O+D channel and 18% in the H+O–D channel.
High friction interface with pseudoelastic NiTi
Authors: Chatterjee S. , Carman G. P.
Published: July 2007

The purpose of this letter is to introduce a mechanism that relies on a stress induced phase transformation to generate a large static friction coefficient (μf). Tribological principles were used to design a frictional interface with pseudoelastic nickel titanium (NiTi) and stainless steel with etched features. At loads large enough to form stress induced martensite increasing the applied load increased μf values. This indicates that mechanical friction instead of adhesive friction may be the dominant mechanism. Using a mechanical model combined with experimental mechanical data, the authors we estimate that μf=0.7 is achievable without substantial plastic deformation.
Pressure-induced amorphization of quasibinary GeTe–Sb2Te3: The role of vacancies
Authors: Kolobov A. V. , Haines J. , Pradel A. , Ribes M. , Fons P. , Tominaga J. , Steimer C. , Aquilanti G. , Pascarelli S.
Published: July 2007

The authors demonstrate that the cubic phase of quasibinary GeTe–Sb2Te3 alloys (GST), the material of choice in phase-change optical recording (such as digital versatile disk-random access memory) can be rendered amorphous by the application of hydrostatic pressure. The amorphization pressure depends on the GST composition. The pressure-induced amorphous phase possesses a local structure around Ge atoms similar to that of laser-amorphized GST. They argue that vacancies are crucial for the pressure-induced amorphization.
On the internal rotations in p-cresol in its ground and first electronically excited states
Authors: Hellweg Arnim , Hättig Christof
Published: July 2007

The overall rotation and internal rotation of p-cresol (4-methyl-phenol) has been studied by comparison of the microwave spectrum with accurate ab initio calculations using the principal axis method in the electronic ground state. Both internal rotations, the torsions of the methyl and the hydroxyl groups relative to the aromatic ring, have been investigated. The internal rotation of the hydroxyl group can be approximately described as the motion of a symmetrical rotor on an asymmetric frame. For the methyl group it has been found that the potential barrier hindering its internal rotation is very small with the first two nonvanishing Fourier coefficients of the potential V3 and V6 in the same order of magnitude. Different splittings of b-type transitions for the A and E species of the methyl torsion indicate a top-top interaction between both internal rotors through the benzene ring. An effective coupling potential for the top-top interaction could be estimated. The hindering barriers of the hydroxyl and methyl rotation have been calculated using second-order Møller-Plesset perturbation theory and the approximate coupled-cluster singles-and-doubles model (CC2) in the ground state and using CC2 and the algebraic diagrammatic construction through second order in the first electronically excited state. The results are in excellent agreement with the experimental values.
Measurement of the x-ray dose-dependent glass transition temperature of structured polymer films by x-ray diffraction
Authors: Keymeulen Heilke R. , Diaz Ana , Solak Harun H. , David Christian , Pfeiffer Franz , Patterson Bruce D. , van der Veen J. Friso , Stoykovich Mark P. , Nealey Paul F.
Published: July 2007

The glass transition temperature (Tg) of polymer nanostructures was measured using a technique based on synchrotron x-ray diffraction from periodic grating structures. Poly(methyl methacrylate) (PMMA) nanostructures consisting of 1:1 lines:spaces with a 100 nm period and 100 nm height were characterized to have a Tg of 118 °C, which is comparable to the Tg of PMMA in bulk systems. The Tg of the PMMA structures also was measured as a function of absorbed x-ray dose. Doses ranging from 0 to 2400 mJ/mm3 were delivered to the PMMA structures prior to the Tg measurements; the Tg of the structures was found to decrease from 118 °C to 95 °C, respectively. The dose dependence of the PMMA glass transition temperature can be attributed to changes in the polymer molecular weight under exposure to x rays.