bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative description of the asymmetry in magnetization transfer effects around the water resonance in the human brain
Authors: Hua Jun , Jones Craig K. , Blakeley Jaishri , Smith Seth A. , van Zijl Peter C.M. , Zhou Jinyuan
Published: September 2007

Magnetization transfer (MT) imaging provides a unique method of tissue characterization by capitalizing on the interaction between solid‐like tissue components and bulk water. We used a continuous‐wave (CW) MT pulse sequence with low irradiation power to study healthy human brains in vivo at 3 T and quantified the asymmetry of the MT effects with respect to the water proton frequency. This asymmetry was found to be a difference of approximately a few percent from the water signal intensity, depending on both the RF irradiation power and the frequency offset. The experimental results could be quantitatively described by a modified two‐pool MT model extended with a shift contribution for the semisolid pool with respect to water. For white matter, this shift was fitted to be 2.34 ± 0.17 ppm (N = 5) upfield from the water signal. Magn Reson Med 58:786–793, 2007. © 2007 Wiley‐Liss, Inc.
TEM transmission line coil with double nuclear capability
Authors: Erickson Matthew G. , Kurpad Krishna N. , Holmes James H. , Fain Sean B.
Published: September 2007

MR imaging and spectroscopy requires RF fields of high homogeneity. Quadrature volume coils meeting this requirement include the birdcage coil and the TEM resonator. We describe here a quadrature volume coil designed around a modified coaxial transmission line in which multiple inner conductors are arrayed on a circular perimeter and surrounded by a common shield. Current antinodes are established at appropriate points on the inner conductors by series transmission line stubs, either open circuit or short circuit, which terminate the line. Quadrature phasing is generated by a novel circuit constructed from a pair of high‐performance current baluns and a commercial quadrature hybrid. The coil is a “pure” TEM coil as it is simply a resonant transmission line. There is no mode structure to consider. The construction of a prototype quadrature four‐element coil is described and preliminary test results from this coil in a 4.7T horizontal bore magnet are reported. A related double nuclear coil design for 3He and 1H in which two linear transmission line coils are arrayed on a circular perimeter and simultaneously tuned and matched to their respective frequencies is also described. Preliminary tests from this coil in a 1.5T clinical scanner are reported. Magn Reson Med 58:800–807, 2007. © 2007 Wiley‐Liss, Inc.
Functional contrast based on intermolecular double‐quantum coherences: Influence of the correlation distance
Authors: Schäfer Andreas , Möller Harald E.
Published: September 2007

A functional MRI (fMRI) study with visual stimulation of healthy subjects was performed at 3T exploiting intermolecular double‐quantum coherences. The correlation distance, dc, was varied between 60 and 300 μm for different evolution times, τ. Robust activation was obtained in all experiments with average signal changes (ΔS2) = 8.4 ± 0.7% and 9.4 ± 0.8% for τ = 15 and 20 ms, respectively) exceeding those normally associated with conventional blood oxygen level‐dependent (BOLD) fMRI. Relaxation‐rate changes (ΔR2 = 0.33 ± 0.36 s−1 and ΔR2* = 0.77 ± 0.54 s−1) were similar to those commonly obtained for the extravascular BOLD effect. The number of activated voxels increased with increasing dc until a plateau was reached at ≈120 μm. Similar trends were observed for the activation‐induced percent signal change and for the maximal Z‐scores. These effects were quantitatively explained by a reduced sensitivity at short dc due to increasing signal attenuation related to diffusion and an increasing amount of signal fluctuations in the fMRI time series due to imperfect suppression of unwanted coherence pathways. Consistent indications of a preferential selection of susceptibility changes in blood vessels of a particular size were not obtained. Magn Reson Med 58:696–704, 2007. © 2007 Wiley‐Liss, Inc.
Elimination of spatial interference in PRESS‐localized editing spectroscopy
Authors: Kaiser Lana G. , Young Karl , Matson Gerald B.
Published: September 2007

Unambiguous detection of γ‐amino butyric acid (GABA) in the human brain is hindered by low concentration and spectral overlap with other metabolites. The popular MEGA‐PRESS (PRESS: point‐resolved spectroscopic sequence) method allows spectral separation of GABA from other metabolites, but suffers from a significant signal‐to‐noise ratio (SNR) reduction due to the 4‐compartment artifact. An alternative PRESS localization technique (PRESS+4) was investigated and compared to MEGA‐PRESS using numerical simulations, phantom, and in vivo experiments. It was shown that while the MEGA‐PRESS method suffers significant signal loss (≈20% for the difference spectrum), GABA signal intensity in PRESS+4 is reduced by only 2% compared to the nonlocalized condition at 4T. The improved method retains important features of the popular MEGA‐PRESS such as additional water suppression and macromolecular elimination as demonstrated in human brain experiments. This method is not limited to GABA J‐difference editing, but can be applied in any PRESS‐based experiments. It should prove particularly useful at higher field, where the 4‐compartment artifact is especially detrimental. Magn Reson Med 58:813–818, 2007. © 2007 Wiley‐Liss, Inc.
A convex optimization procedure to compute ℋ︁2and ℋ︁∞norms for uncertain linear systems in polytopic domains
Authors: Oliveira Ricardo C. L. F. , Peres Pedro L. D.
Published: September 2007

In this paper, a convergent numerical procedure to compute ℋ︁2and ℋ︁∞norms of uncertain time‐invariant linear systems in polytopic domains is proposed. The norms are characterized by means of homogeneous polynomially parameter‐dependent Lyapunov functions of arbitrary degreegsolving parameter‐dependent linear matrix inequalities. Using an extension of Pólya's Theorem to the case of matrix‐valued polynomials, a sequence of linear matrix inequalities is constructed in terms of an integerdproviding a Lyapunov solution for a given degreegand guaranteed ℋ︁2and ℋ︁∞costs whenever such a solution exists. As the degree of the homogeneous polynomial matrices increases, the guaranteed costs tend to the worst‐case norm evaluations in the polytope. Both continuous‐ and discrete‐time uncertain systems are investigated, as illustrated by numerical examples that include comparisons with other techniques from the literature. Copyright © 2007 John Wiley & Sons, Ltd.
Use of benzodiazepines and benzodiazepine receptor agonists during pregnancy: neonatal outcome and congenital malformations
Authors: Wikner Birgitta Norstedt , Stiller Carl‐Olav , Bergman Ulf , Asker Charlotte , Källén Bengt
Published: September 2007

Background

Exposure to Benzodiazepines (BZD) during foetal life has been suggested to contribute to neonatal morbidity and some congenital malformations, for example, orofacial clefts. Here we aimed to study the neonatal outcome and congenital malformations in neonates whose mothers reported use of BZD and/or hypnotic benzodiazepine receptor agonists (HBRA) during pregnancy.

Methods

In the Swedish Medical Birth Register we identified 1979 infants whose mothers (n = 1944) reported use of BZD and/or HBRA in early pregnancy. An additional 401 infants were studied, born to 390 mothers who were prescribed such drugs during late pregnancy. Neonatal outcome including congenital malformations after exposure was compared with that of all births (n = 873 879).

Results

An increased risk for preterm birth and low birth weight was detected in the exposed population. The rate of relatively major congenital malformations was moderately increased among infants exposed in early pregnancy (adjusted OR = 1.24, 95%CI 1.00–1.55), not explained by known teratogenic maternal co‐medication. A higher than expected number of infants with pylorostenosis or alimentary tract atresia (especially small gut) was found. This was, however, based on only seven infants for each group of malformation without association to any specific BZD or HBRA. The earlier proposed increased risk for orofacial clefts was not confirmed in our study.

Conclusions

Maternal use of BZD and/or HBRA may increase the risk for preterm birth and low birth weight and cause neonatal symptoms, but does not appear to have a strong teratogenic potential. The tentative association with pylorostenosis and alimentary tract atresia needs confirmation. Copyright © 2007 John Wiley & Sons, Ltd.
From carbon nanotube coatings to high‐performance polymer nanocomposites
Authors: Bredeau Stéphane , Peeterbroeck Sophie , Bonduel Daniel , Alexandre Michaël , Dubois Philippe
Published: September 2007

Since their discovery at the beginning of the 1990s, carbon nanotubes (CNTs) have been the focus of considerable research by both academia and industry due to their remarkable and unique electronic and mechanical properties. Among numerous potential applications of CNTs, their use as reinforcing materials for polymers has recently received considerable attention since their exceptional mechanical properties, combined with their low density, offer tremendous opportunities for the development of fundamentally new material systems. However, the key challenge remains to reach a high level of nanoparticle dissociation (i.e. to break down the cohesion of aggregated CNTs) as well as a fine dispersion upon melt blending within the selected matrices. Therefore, this contribution aims at reviewing the exceptional efficiency of CNT coating by a thin layer of polymer as obtained by an in situ polymerization process catalysed directly from the nanofiller surface, known as the ‘polymerization‐filling technique’. This process allows for complete destructuring of the native filler aggregates. Interestingly enough, such surface‐coated carbon nanotubes can be added as ‘masterbatch’ in commercial polymeric matrices leading to the production of polymer nanocomposites displaying much better thermomechanical, flame retardant and electrical conductive properties even at very low filler loading. Copyright © 2007 Society of Chemical Industry
Sputum antibiotic concentrations: Implications for treatment of cystic fibrosis lung infection
Authors: Moriarty T.F. , McElnay J.C. , Elborn J.S. , Tunney M.M.
Published: September 2007

Background

The success of antibiotic therapy may be predicted based on the achievement of pharmacodynamic indices (PDIs), which are determined by the susceptibility of the infecting bacteria and the concentrations of antibiotics achieved at the site of infection. The aim of this study was to determine whether PDIs associated with clinical effectiveness for ceftazidime and tobramycin were achieved at the site of infection in the lungs of cystic fibrosis (CF) patients following intravenous administration during treatment of an acute exacerbation.

Methods

Serum and sputum samples were collected from 14 CF patients and the concentration of both antibiotics in the samples determined. The susceptibility of bacteria cultured from sputum samples to both antibiotics alone and in combination was also determined.

Results

A total of 22 Pseudomonas aeruginosa isolates and 4 Burkholderia cepacia complex isolates were cultured from sputum samples with 55% and 4% of isolates susceptible to ceftazidime and tobramycin, respectively. Target PDIs for ceftazidime and tobramycin, an AUC/MIC ratio of 100 and a Cmax/MIC ratio of 10, respectively, were not achieved in serum or sputum simultaneously or even individually for any patient. Although the combination of ceftazidime and tobramycin was synergistic against 20 of the 26 isolates cultured, the concentrations of both antibiotics required for synergy were achieved simultaneously in only 38% of serum and 14% of sputum samples.

Conclusion

Key PDIs associated with clinical effectiveness for ceftazidime and tobramycin were not achieved at the site of infection in the lungs of CF patients. 2007;42:1008–1017. © 2007 Wiley‐Liss, Inc.
Alterations in cGMP, soluble guanylate cyclase, phosphodiesterase 5, and B‐type natriuretic peptide induced by chronic increased pulmonary blood flow in lambs
Authors: Oishi Peter , Sharma Shruti , Grobe Albert , Azakie Anthony , Harmon Cynthia , Johengen Michael J. , Hsu Jong‐Hau , Fratz Sohrab , Black Stephen M. , Fineman Jeffrey R.
Published: September 2007

Objective

The objective of the study was to determine alterations in cGMP, soluble guanylate cyclase (sGC), phosphodiesterase type 5 (PDE5), and B‐type natriuretic peptide (BNP), in an animal model of a congenital cardiac defect with increased pulmonary blood flow.

Design

Prospective, comparative, experimental study.

Subjects

Lambs, from birth until 8 weeks of age.

Methodology

Late gestation fetal lambs underwent in utero placement of an 8 mm aortopulmonary vascular graft (shunt). In shunted and normal age‐matched control lambs, at 2, 4, and 8 weeks of age, cGMP and BNP levels were measured, and sGC subunit and PDE5 protein expression were determined by Western blot analysis and immunohistochemistry.

Results

In shunted lambs, tissue and plasma cGMP levels were greater than normal throughout the 8‐week study period (P < 0.05). sGCα protein was greater at 2 and 4 weeks (P < 0.05), and sGCβ and PDE5 protein were greater at 4 weeks in shunted lambs (P < 0.05). Plasma BNP levels did not change in normal lambs but increased in shunted lambs by 8 weeks of age (P < 0.05). BNP levels were greater in shunted lambs than normal at 4 and 8 weeks (P < 0.05).

Conclusions

Alterations in sGC subunit protein expression during the first post‐natal month, and increased BNP levels during the second post‐natal month contribute to elevations in plasma and lung tissue cGMP in lambs with increased pulmonary blood flow. 2007;42:1057–1071. © 2007 Wiley‐Liss, Inc.
Partnership working within the new ABPI code of practice
Authors: Rao Shailen
Published: September 2007

The new ABPI code of practice was published last year. Here the author describes the key changes and their effect on joint initiatives with the pharmaceutical industry. Copyright © 2007 Wiley Interface Ltd
Psoriasis: not just a skin disease
Authors: Freeman Keith
Published: September 2007

Psoriasis is commonly treated in general practice, but many GPs fail to address the systemic and psychosocial aspects of having a chronic, incurable skin disease. Here the author highlights the problems that accompany psoriasis and comments on how management can be improved. Copyright © 2007 Wiley Interface Ltd
Choosing an appropriate dressing for chronic wounds
Authors: Bell Denise , Hyam Dot
Published: September 2007

Chronic wounds are non‐healing with a sometimes complex aetiology, and dressing such wounds can be difficult and time con‐suming. Here the authors describe how to select the appropriate wound dressing according to wound charac‐teristics. Copyright © 2007 Wiley Interface Ltd
Defect formation in GaN grown on vicinal 4H‐SiC (0001) substrates
Authors: Rudziński M. , Jezierska E. , Weyher J. L. , Macht L. , Hageman P. R. , Borysiuk J. , Rödle T. C. , Jos H. F. F. , Larsen P. K.
Published: September 2007

We report a comparative study of wurtzite GaN epilayers prepared by Metal Organic Chemical Vapor Deposition on 4H‐SiC substrates of orientation vicinal to the (0001) (misorientation 0°, 3.4°, and 8°). Structural analysis using X‐ray diffraction, defect‐selective etching methods, and (High Resolution‐) Transmission Electron Microscopy provides direct evidence for a higher number of defects in GaN epilayers grown on the 8° misoriented substrate compared to the 3.4° and 0° misoriented substrates. We found strong differences in morphology of the GaN epilayers and in type and density of the defects formed during growth on both vicinal and nominally exact oriented SiC substrates. The formation of clusters of defects and the non‐uniform distribution of strain, resulting in preferential cracking of the GaN films along the [11$ \bar 2 $0] direction, are both results of growth on misoriented substrates. Based on experimental results, the growth mechanism is discussed and a model explaining the defect formation is proposed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ammoniated solvation of excess electrons on molecular surfaces
Authors: Jalbout Abraham F.
Published: September 2007

As previously asserted, we have proposed a set of hypothetical molecular surfaces that possessed an extended hydrogen‐bonded network on one of the sides and hydrogen atoms on the opposite side. The uneven distribution of the OH groups (which increases the total dipole moment of the system) coupled to the partial positive charge of the hydrogen atoms creates charge pockets capable of trapping excess electrons. In this work we consider the ability of ammonia (NH3) in solvating excess electrons in charge pockets on molecular surfaces. The anions are stable with respect to vertical electron detachment, and serve as another example by which electrons can be solvated on molecular surfaces. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Trapping excess electrons in charge pockets on molecular surfaces in an argon matrix
Authors: Jalbout Abraham F.
Published: September 2007

Recently, we have proposed a series of hydrocarbon molecular surfaces (A.F. Jalbout, L. Adamowicz, Mol Phys 2006, 19, 3101), which had a hydrogen bonded network of OH groups on one side of the surface and hydrogen atoms on the opposite side. The addition of these OH groups increases the dipole moment of the system allowing for excess electrons to attach to the surface in dipole‐bound (DB) anion states. We have used this principle to study the interaction of the DB anions formed from the surfaces and an argon atom. The resulting anions are shown to be stable with respect to electron detachment. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Formation of simple organic molecules in the interstellar medium
Authors: Jalbout Abraham F. , Contreras‐Torres Flavio F. , De Leon Aned
Published: September 2007

In this work we present a methodology for the synthesis of simple molecules from basic formaldehyde (H2CO) precursors. We have approached this challenging problem by considering a basic dimerization scheme that eventually leads to diose and methyl formate, using an HCO+ proton source. This species was chosen due to its ample abundance in the atmosphere. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Correction
Authors: Shinomoto Shigeru , Koyama Shinkuke
Published: September 2007

‘A solution to the controversy between rate and temporal coding’ by Shigeru Shinomoto and Shinsuke Koyama (Statistics in Medicine, this issue. DOI: 10.1002/SIM.2932). The authors would like to correct Figure 1, for which the wrong rasters were put in (a), (b) and (c), and present here the corrected figure.

1. Corrected figure.

magnified image

1. Corrected figure.
Pelvic arterial pseudoaneurysm—a rare complication of Cesarean section: diagnosis and novel treatment
Authors: Kovo M. , Behar D. J. , Friedman V. , Malinger G.
Published: September 2007

An uncommon cause of delayed postpartum hemorrhage is a pseudoaneurysm of the uterine artery. Pelvic arterial pseudoaneurysm is generally treated by laparotomy and hemostatic sutures or by uterine artery embolization. We describe two cases of late postpartum hemorrhage following Cesarean section, attributed to pelvic arterial pseudoaneurysm, that were successfully treated by direct thrombin injection under ultrasound guidance. Percutaneous or transvaginal ultrasound‐guided direct thrombin injection is a simple procedure that does not require any sophisticated surgical or radiological equipment. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Uterine artery Doppler at 11 + 0 to 13 + 6 weeks in the prediction of pre‐eclampsia
Authors: Plasencia W. , Maiz N. , Bonino S. , Kaihura C. , Nicolaides K. H.
Published: September 2007

Objective

To determine the performance of screening for pre‐eclampsia (PET) by maternal characteristics and uterine artery pulsatility index (PI) at 11 + 0 to 13 + 6 weeks' gestation.

Methods

In women with singleton pregnancies attending for routine care at 11 + 0 to 13 + 6 weeks' gestation we recorded maternal variables and measured the uterine artery PI. We identified 107 cases that subsequently developed PET and 5041 that were unaffected by PET, gestational hypertension or delivery of newborns with birth weight below the 10th centile. A multivariate Gaussian model was fitted to the distribution of log multiples of the median (MoM) PI in the PET and unaffected groups. Likelihood ratios for log MoM PI were computed and used together with maternal variables to produce patient‐specific risks for each case. Predicted detection rates (DR) and false‐positive rates (FPR) were calculated by taking the proportions with risks above a given risk threshold.

Results

In the unaffected group log MoM PI was influenced by maternal ethnic origin, body mass index, previous history of PET and fetal crown–rump length. In the prediction of PET significant contributions were provided by log MoM PI, ethnic origin, body mass index and previous and family history of PET. For an FPR of 10% the DRs of all PET and PET leading to delivery before 34 weeks' gestation by log MoM PI and maternal variables were 61.7% and 81.8%, respectively.

Conclusion

Maternal variables together with uterine artery PI at 11 + 0 to 13 + 6 weeks' gestation provide sensitive prediction of the development of PET, especially of severe early‐onset PET. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Studies of the refractive indices of binary wax mixtures
Authors: Concetta Waller Sister M. , Angelice Seibert Sister M.
Published: September 2007

The greatest deviations in refractive index from ideal behavior of the binary wax mixtures are obtained with mixtures of vegetable waxes. These are waxes with higher unsaturation, waxes containing a higher percentage of hydroxy esters, and waxes containing glycerides or combinations of these.

Melting points and refractive indices at the melting points can be determined simultaneously with the Abbe‐56 refractometer.
The Bilhaut-Cloquet Procedure for Wassel Types III, IV and VII Thumb Duplication
Authors: TONKIN M. A. , BULSTRODE N. W.
Published: September 2007

Five cases of Wassel types III, IV and VII thumb duplication underwent a Bilhaut-Cloquet procedure. A stable and mobile metacarpophalangeal joint was achieved in all cases. Interphalangeal joint motion was limited but this joint was stable in all cases. The nail ridge in these thumbs was minimal. A strong, stable thumb of normal size and good appearance can result from the Bilhaut-Cloquet procedure. When one nail is 70% of normal width, a modified procedure using the whole of one nail will avoid the nail ridge, but the nail will still differ from normal.
Large euenantiornithine birds from the Cretaceous of southern France, North America and Argentina
Authors: WALKER C. A. , BUFFETAUT E. , DYKE G. J.
Published: September 2007

We review historical approaches to the systematics of Enantiornithes, the dominant birds of the second half of the Mesozoic, and describe the forelimb remains of a new Cretaceous euenantiornithine. This taxon is known on the basis of fossil specimens collected from southern France, Argentina and the United States; such a wide geographical distribution is uncharacteristic for Enantiornithes as most taxa are known from single localities. Fossils from the Massecaps locality close to the village of Cruzy (Hérault, southern France), in combination with elements from New Mexico (USA) and from the Argentine locality of El Brete (Salta Province) testify to the global distribution of large flighted euenantiornithine birds in the Late Cretaceous. We discuss the systematics and taxonomy of additional isolated bones of Enantiornithes that were collected from the Argentine El Brete locality in the 1970s; the presence of these flying birds in Cretaceous rocks on both sides of the equator, in both northern and southern hemispheres, further demonstrates the ubiquity of this avian lineage by the latter stages of the Mesozoic.
Is it worth learning differential geometric methods for modeling and control of mechanical systems?
Authors: Lewis Andrew D.
Published: September 2007

Evidence is presented to indicate that the answer is, “Yes, sometimes.”
Changes in neighbourhood food store environment, food behaviour and body mass index, 1981–1990
Authors: Wang May C , Cubbin Catherine , Ahn Dave , Winkleby Marilyn A
Published: September 2007

Objective

This paper examines trends in the neighbourhood food store environment (defined by the number and geographic density of food stores of each type in a neighbourhood), and in food consumption behaviour and overweight risk of 5779 men and women.

Design

The study used data gathered by the Stanford Heart Disease Prevention Program in four cross-sectional surveys conducted from 1981 to 1990.

Setting

Four mid-sized cities in agricultural regions of California.

Subjects

In total, 3154 women and 2625 men, aged 25–74 years.

Results

From 1981 to 1990, there were large increases in the number and density of neighbourhood stores selling sweets, pizza stores, small grocery stores and fast-food restaurants. During this period, the percentage of women and men who adopted healthy food behaviours increased but so did the percentage who adopted less healthy food behaviours. The percentage who were obese increased by 28% in women and 24% in men.

Conclusion

Findings point to increases in neighbourhood food stores that generally offer mostly unhealthy foods, and also to the importance of examining other food pattern changes that may have a substantial impact on obesity, such as large increases in portion sizes during the 1980s.
Muskelschmerzen
Authors: Tanneberger  , Stöckli  , Zimmerli
Published: September 2007

Eine 62-jährige Patientin stellt sich mit Myalgien, Dysphagie und Tagesmüdigkeit vor. Die initiale klinische Untersuchung ist unauffällig. Laborchemisch zeigen sich eine Hyperthyreose und eine deutlich erhöhte Blutsenkungsgeschwindigkeit. In der Folge kann aufgrund von Klinik und Bildgebung eine Thyreoiditis De Quervain diagnostiziert werden. Im weiteren Verlauf kommt es zu einer Normalisierung der Schilddrüsenparameter und die Patientin ist unter symptomatischer Therapie mit NSAR beschwerdefrei.
Thermochronology constraints for the propagation sequence of the south Pyrenean basement thrust system (France‐Spain)
Authors: Jolivet Marc , Labaume Pierre , Monié Patrick , Brunel Maurice , Arnaud Nicolas , Campani Marion
Published: September 2007

In this work we combined apatite fission track and biotite/K‐feldspar 40Ar/39Ar ages with tectonic data in the west central part of the Axial Zone of the Pyrenees. We discuss the exhumation ages and rates of the Néouvielle, Bordère‐Louron, and Bielsa Variscan granites and their relationships with the timing and sequence of south vergent basement thrusting within the Pyrenean orogenic prism. The 40Ar/39Ar ages on K‐feldspars from the Néouvielle massif (sample NV7) seem to indicate tectonic movements on the Eaux‐Chaudes thrust during the early middle Eocene. Fission track results suggest that the exhumation of the Néouvielle massif occurred around 35 Ma and exhumation of the Bordère‐Louron massif around 32 Ma in relation to thrusting on the Gavarnie thrust. The Bielsa massif was exhumed from around 19 Ma by out‐of‐sequence movements on the Bielsa thrust. We thus show that whereas most of the Pyrenean basement thrust faults (here the Eaux‐Chaudes, Gavarnie, and Guarga thrusts) were active in sequence toward the southern foreland from the early Eocene to the earliest Miocene, some of them (here the Bielsa thrust) were activated out of sequence in the hinterland, later than the generally accepted Aquitanian age for the end of the Pyrenean compression. Finally, the apatite fission track modeling indicate a last cooling episode starting around 5 Ma which is most certainly related to the Pliocene reexcavation of the southern and northern flanks of the Pyrenees.
Spatiotemporal topological kriging of runoff time series
Authors: Skøien Jon Olav , Blöschl Günter
Published: September 2007

This paper proposes a geostatistical method for estimating runoff time series in ungauged catchments. The method conceptualizes catchments as space‐time filters and exploits the space‐time correlations of runoff along the stream network topology. We hence term the method topological kriging or top kriging. It accounts for hydrodynamic and geomorphologic dispersion as well as routing and estimates runoff as a weighted average of the observed runoff in neighboring catchments. Top kriging is tested by cross validation on 10 years of hourly runoff data from 376 catchments in Austria and separately for a subset of these data, the Innviertel region. The median Nash‐Sutcliffe efficiency of hourly runoff in the Innviertel region is 0.87 but decreases to 0.75 for the entire data set. For a subset of 208 catchments, the median efficiency of daily runoff estimated by top kriging is 0.87 as compared to 0.67 for estimates of a deterministic runoff model that uses regionalized model parameters. The much better performance of top kriging is because it avoids rainfall data errors and avoids the parameter identifiability issues of traditional runoff models. The analyses indicate that the kriging variance can be used for identifying catchments with potentially poor estimates. The Innviertel region is used to examine the kriging weights for nested and nonnested catchments and to compare various variants of top kriging. The spatial kriging variant generally performs better than the more complex spatiotemporal kriging and spatiotemporal cokriging variants. It is argued that top kriging may be preferable to deterministic runoff models for estimating runoff time series in ungauged catchments, provided stream gauge density is high and there is no need to account for causal rainfall‐runoff processes. Potential applications include the estimation of flow duration curves in a region and near–real time mapping of runoff.
Spin‐period effects in magnetospheres with no axial tilt
Authors: Carbary J. F. , Mitchell D. G. , Krimigis S. M. , Hamilton D. C. , Krupp N.
Published: September 2007

A magnetic axis that is tilted with respect to the spin axis causes waves that generate spin‐periodic effects in a planet's outer magnetosphere. Saturn's magnetic axis is aligned with its spin axis, and yet its outer magnetosphere exhibits spin‐periodicities in all species of charged particles, just as expected from a wavy magnetodisk. In a spin‐aligned geometry, however, a rotating anomaly (or “cam”) in the inner magnetosphere can also generate spin‐periodic waves by shaking the plasma sheet of the outer magnetosphere. Like a wobbling magnetodisk, this model predicts oscillations of the plasma sheet at distances beyond ∼20 RS (1 RS = 60268 km). When viewed from a moving spacecraft, these oscillations cause charged particle periodicities near the spin period of the planet. The phase and polarity of these periodicities should change systematically with local time, and spin‐periodic effects should appear along the magnetopause.
Tidally generated near‐resonant internal wave triads at a shelf break
Authors: Lamb K. G.
Published: September 2007

Numerical simulations of internal wave generation by tidal flow over a shelf break using a linear background stratification show the presence of near‐resonant internal wave triads with spatially modulated amplitudes propagating away from the shelf break. The near‐resonant triad is comprised of mode‐one and ‐three waves of tidal frequency, which are directly forced by the tide‐topography interaction, and a second harmonic, mode‐two wave generated by the nonlinear interaction of these waves. A theory for these near‐resonant triads is presented and compared with the numerical simulations.
Mars solar wind interaction: Formation of the Martian corona and atmospheric loss to space
Authors: Chaufray J. Y. , Modolo R. , Leblanc F. , Chanteur G. , Johnson R. E. , Luhmann J. G.
Published: September 2007

A three‐dimensional (3‐D) atomic oxygen corona of Mars is computed for periods of low and high solar activities. The thermal atomic oxygen corona is derived from a collisionless Chamberlain approach, whereas the nonthermal atomic oxygen corona is derived from Monte Carlo simulations. The two main sources of hot exospheric oxygen atoms at Mars are the dissociative recombination of O2+between 120 and 300 km and the sputtering of the Martian atmosphere by incident O+pickup ions. The reimpacting and escaping fluxes of pickup ions are derived from a 3‐D hybrid model describing the interaction of the solar wind with our computed Martian oxygen exosphere. In this work it is shown that the role of the sputtering crucially depends on an accurate description of the Martian corona as well as of its interaction with the solar wind. The sputtering contribution to the total oxygen escape is smaller by one order of magnitude than the contribution due to the dissociative recombination. The neutral escape is dominant at both solar activities (1 × 1025s−1for low solar activity and 4 × 1025s−1for high solar activity), and the ion escape flux is estimated to be equal to 2 × 1023s−1at low solar activity and to 3.4 × 1024s−1at high solar activity. This work illustrates one more time the strong dependency of these loss rates on solar conditions. It underlines the difficulty of extrapolating the present measured loss rates to the past solar conditions without a better theoretical and observational knowledge of this dependency.
Neuronal HIF-1α Protein and VEGFR-2 Immunoreactivity in Functionally Related Motor Areas following a Focal M1 Infarct
Authors: Stowe Ann M , Plautz Erik J , Nguyen Phuong , Frost Shawn B , Eisner-Janowicz Ines , Barbay Scott , Dancause Numa , Sensarma Anirban , Taylor Michael D , Zoubina Elena V , Nudo Randolph J
Published: September 2007

Clinical and experimental data support a role for the intact cortex in recovery of function after stroke, particularly ipsilesional areas interconnected to the infarct. There is, however, little understanding of molecular events in the intact cortex, as most studies focus on the infarct and peri-infarct regions. This study investigated neuronal immunoreactivity for hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2) in remote cortical areas 3 days after a focal ischemic infarct, as both HIF-1α and VEGFR-2 have been implicated in peri-infarct neuroprotection. For this study, intracortical microstimulation techniques defined primary motor (M1) and premotor areas in squirrel monkeys (genus Saimiri). An infarct was induced in the M1 hand representation, and immunohistochemical techniques identified neurons, HIF-1α and VEGFR-2. Stereologic techniques quantified the total neuronal populations and the neurons immunoreactive for HIF-1α or VEGFR-2. The results indicate that HIF-1α upregulation is confined to the infarct and peri-infarct regions. Increases in VEGFR-2 immunoreactivity occurred; however, in two remote regions: the ventral premotor hand representation and the M1 hindlimb representation. Neurons in these representations were previously shown to undergo significant increases in VEGF protein immunoreactivity, and comparison of the two data sets showed a significant correlation between levels of VEGF and VEGFR-2 immunoreactivity. Thus, while remote areas undergo a molecular response to the infarct, we hypothesize that there is a delay in the initiation of the response, which ultimately may increase the ‘window of opportunity’ for neuroprotective interventions in the intact cortex.
Study of the mode of action of a polygalacturonase from the phytopathogen Burkholderia cepacia
Authors: Massa Claudia , Clausen Mads H. , Stojan Jure , Lamba Doriano , Campa Cristiana
Published: September 2007

We have recently isolated and heterologously expressed BcPeh28A, an endopolygalacturonase from the phytopathogenic Gram-negative bacterium Burkholderia cepacia. Endopolygalacturonases belong to glycoside hydrolase family 28 and are responsible for the hydrolysis of the non-esterified regions of pectins. The mode of action of BcPeh28A on different substrates has been investigated and its enzymatic mechanism elucidated. The hydrolysis of polygalacturonate indicates that BcPeh28A is a non-processive enzyme that releases oligomers with chain lengths ranging from two to eight. By inspection of product progression curves, a kinetic model has been generated and extensively tested. It has been used to derive the kinetic parameters that describe the time course of the formation of six predominant products. Moreover, an investigation of the enzymatic activity on shorter substrates that differ in their overall length and methylation patterns sheds light on the architecture of the BcPeh28A active site. Specifically the tolerance of individual sites towards methylated saccharide units was rationalized on the basis of the hydrolysis of hexagalacturonides with different methylation patterns.
Protein phosphatase-1 is a novel regulator of the interaction between IRBIT and the inositol 1,4,5-trisphosphate receptor
Authors: Devogelaere Benoit , Beullens Monique , Sammels Eva , Derua Rita , Waelkens Etienne , van Lint Johan , Parys Jan B. , Missiaen Ludwig , Bollen Mathieu , De Smedt Humbert
Published: September 2007

IRBIT is an IP3R [IP3 (inositol 1,4,5-trisphosphate) receptor]-binding protein that competes with IP3 for binding to the IP3R. Phosphorylation of IRBIT is essential for the interaction with the IP3R. The unique N-terminal region of IRBIT, residues 1–104 for mouse IRBIT, contains a PEST (Pro-Glu-Ser-Thr) domain with many putative phosphorylation sites. In the present study, we have identified a well-conserved PP1 (protein phosphatase-1)-binding site preceeding this PEST domain which enabled the binding of PP1 to IRBIT both in vitro and in vivo. IRBIT emerged as a mediator of its own dephosphorylation by associated PP1 and, hence, as a novel substrate specifier for PP1. Moreover, IRBIT-associated PP1 specifically dephosphorylated Ser68 of IRBIT. Phosphorylation of Ser68 was required for subsequent phosphorylation of Ser71 and Ser74, but the latter two sites were not targeted by PP1. We found that phosphorylation of Ser71 and Ser74 were sufficient to enable inhibition of IP3 binding to the IP3R by IRBIT. Finally, we have shown that mutational inactivation of the docking site for PP1 on IRBIT increased the affinity of IRBIT for the IP3R. This pinpoints PP1 as a key player in the regulation of IP3R-controlled Ca2+ signals.
Cytochrome c impaled: investigation of the extended lipid anchorage of a soluble protein to mitochondrial membrane models
Authors: Kalanxhi Erta , Wallace Carmichael J. A.
Published: September 2007

Cyt c (cytochrome c) has been traditionally envisioned as rapidly diffusing in two dimensions at the surface of the mitochondrial inner membrane when not engaged in redox reactions with physiological partners. However, the discovery of the extended lipid anchorage (insertion of an acyl chain of a bilayer phospholipid into the protein interior) suggests that this may not be exclusively the case. The physical and structural factors underlying the conformational changes that occur upon interaction of ferrous cyt c with phospholipid membrane models have been investigated by monitoring the extent of the spin state change that result from this interaction. Once transiently linked by electrostatic forces between basic side chains and phosphate groups, the acyl chain entry may occur between two parallel hydrophobic polypeptide stretches that are surrounded by positively charged residues. Alteration of these charges, as in the case of non-trimethylated (TML72K) yeast cyt c and Arg91Nle horse cyt c (where Nle is norleucine), led to a decline in the binding affinity for the phospholipid liposomes. The electrostatic association was sensitive to ionic strength, polyanions and pH, whereas the hydrophobic interactions were enhanced by conformational changes that contributed to the loosening of the tertiary structure of cyt c. In addition to proposing a mechanistic model for the extended lipid anchorage of cyt c, we consider what, if any, might be the physiological relevance of the phenomenon.
Regulation of multisite phosphorylation and 14-3-3 binding of AS160 in response to IGF-1, EGF, PMA and AICAR
Authors: Geraghty Kathryn M. , Chen Shuai , Harthill Jean E. , Ibrahim Adel F. , Toth Rachel , Morrice Nick A. , Vandermoere Franck , Moorhead Greg B. , Hardie D. Grahame , MacKintosh Carol
Published: September 2007

AS160 (Akt substrate of 160 kDa) mediates insulin-stimulated GLUT4 (glucose transporter 4) translocation, but is widely expressed in insulin-insensitive tissues lacking GLUT4. Having isolated AS160 by 14-3-3-affinity chromatography, we found that binding of AS160 to 14-3-3 isoforms in HEK (human embryonic kidney)-293 cells was induced by IGF-1 (insulin-like growth factor-1), EGF (epidermal growth factor), PMA and, to a lesser extent, AICAR (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside). AS160-14-3-3 interactions were stabilized by chemical cross-linking and abolished by dephosphorylation. Eight residues on AS160 (Ser318, Ser341, Thr568, Ser570, Ser588, Thr642, Ser666 and Ser751) were differentially phosphorylated in response to IGF-1, EGF, PMA and AICAR. The binding of 14-3-3 proteins to HA–AS160 (where HA is haemagglutinin) was markedly decreased by mutation of Thr642 and abolished in a Thr642Ala/Ser341Ala double mutant. The AGC (protein kinase A/protein kinase G/protein kinase C-family) kinases RSK1 (p90 ribosomal S6 kinase 1), SGK1 (serum- and glucocorticoid-induced protein kinase 1) and PKB (protein kinase B) displayed distinct signatures of AS160 phosphorylation in vitro: all three kinases phosphorylated Ser318, Ser588 and Thr642; RSK1 also phosphorylated Ser341, Ser751 and to a lesser extent Thr568; and SGK1 phosphorylated Thr568 and Ser751. AMPK (AMP-activated protein kinase) preferentially phosphorylated Ser588, with less phosphorylation of other sites. In cells, the IGF-1-stimulated phosphorylations, and certain EGF-stimulated phosphorylations, were inhibited by PI3K (phosphoinositide 3-kinase) inhibitors, whereas the RSK inhibitor BI-D1870 inhibited the PMA-induced phosphorylations. The expression of LKB1 in HeLa cells and the use of AICAR in HEK-293 cells promoted phosphorylation of Ser588, but only weak Ser341 and Thr642 phosphorylations and binding to 14-3-3s. Paradoxically however, phenformin activated AMPK without promoting AS160 phosphorylation. The IGF-1-induced phosphorylation of the novel phosphorylated Ser666-Pro site was suppressed by AICAR, and by combined mutation of a TOS (mTOR signalling)-like sequence (FEMDI) and rapamycin. Thus, although AS160 is a common target of insulin, IGF-1, EGF, PMA and AICAR, these stimuli induce distinctive patterns of phosphorylation and 14-3-3 binding, mediated by at least four protein kinases.
Timed interactions between viral and cellular replication factors during the initiation of SV40 in vitro DNA replication
Authors: Taneja Poonam , Nasheuer Heinz-Peter , Hartmann Hella , Grosse Frank , Fanning Ellen , Weisshart Klaus
Published: September 2007

The initiation of SV40 (simian virus 40) DNA replication requires the co-operative interactions between the viral Tag (large T-antigen), RPA (replication protein A) and Pol (DNA polymerase α-primase) on the template DNA. Binding interfaces mapped on these enzymes and expressed as peptides competed with the mutual interactions of the native proteins. Prevention of the genuine interactions was accomplished only prior to the primer synthesis step and blocked the assembly of a productive initiation complex. Once the complex was engaged in the synthesis of an RNA primer and its extension, the interfering effects of the peptides ceased, suggesting a stable association of the replication factors during the initiation phase. Specific antibodies were still able to disrupt preformed interactions and inhibited primer synthesis and extension activities, underlining the crucial role of specific protein–protein contacts during the entire initiation process.
Astrocyte signaling in the presence of spatial inhomogeneities
Authors: Stamatakis Michail , Mantzaris Nikos V.
Published: September 2007

Astrocytes, a special type of glial cells, were considered to have just a supporting role in information processing in the brain. However, several recent studies have shown that they can be chemically stimulated by various neurotransmitters, such as ATP, and can generate Ca2+ and ATP waves, which can propagate over many cell lengths before being blocked. Although pathological conditions, such as spreading depression and epilepsy, have been linked to abnormal wave propagation in astrocytic cellular networks, a quantitative understanding of the underlying characteristics is still lacking. Astrocytic cellular networks are inhomogeneous, in the sense that the domain they occupy contains passive regions or gaps, which are unable to support wave propagation. Thus, this work focuses on understanding the complex interplay between single-cell signal transduction, domain inhomogeneity, and the characteristics of wave propagation and blocking in astrocytic cellular networks. The single-cell signal transduction model that was employed accounts for ATP-mediated IP3 production, the subsequent Ca2+ release from the ER, and ATP release into the extracellular space. The model is excitable and thus an infinite range of wave propagation is observed if the domain of propagation is homogeneous. This is not always the case for inhomogeneous domains. To model wave propagation in inhomogeneous astrocytic networks, a reaction-diffusion framework was developed and one-gap as well as multiple-gap cases were simulated using an efficient finite-element algorithm. The minimum gap length that blocks the wave was computed as a function of excitability levels and geometric characteristics of the inhomogeneous network, such as the length of the active regions (cells). Complex transient patterns, such as wave reflection, wave trapping, and generation of echo waves, were also predicted by the model, and their relationship to the geometric characteristics of the network was evaluated. Therefore, the proposed model can help in the formulation of testable hypotheses to explain the observed abnormal wave propagation in pathological situations.
Analyzing molecular properties calculated with two-component relativistic methods using spin-free natural bond orbitals: NMR spin-spin coupling constants
Authors: Autschbach Jochen
Published: September 2007

An analysis method for static linear response properties employing two-component (spin-orbit) relativistic density functional theory along with scalar relativistic “natural localized molecular orbitals” (NLMOs) and “natural bond orbitals” (NBOs) has been developed. The spin-orbit NLMO/NBO analysis has been applied to study the indirect spin-spin coupling (J-coupling) constants in Tl–I, PbH4, and a dinuclear Pt–Tl bonded complex with a very large Pt–Tl coupling constant (expt.: 146.8kHz). For Tl–I it is shown that the analysis scheme based on scalar relativistic NLMOs is applicable even if spin-orbit coupling is responsible for most of the coupling’s magnitude. For PbH4 it is shown that electron delocalization plays a much larger role for the Pb–H coupling than it is the case for the C–H coupling in methane. For the Pt–Tl complex the analysis clearly demonstrates the strong influence of the ligands on the Pt–Tl coupling constant and quantifies the effect of the delocalization of the Pt–Tl bond on the Pt–Tl coupling constant.