bluuebunny/crossref_metadata_2025_split huggingface dataset:
New imaging method for assessing pelvic floor biomechanics
Authors: Thyer I. , Shek C. , Dietz H. P. 
Published: February 2008

AbstractObjectivesThe investigation of female pelvic floor biomechanics is attracting attention due to its importance in pelvic floor dysfunction and childbirth. To date, there are no established means of assessing pelvic floor elasticity. We propose the use of translabial ultrasound to estimate strain, one element of pubovisceral muscle elasticity.MethodsUltrasound datasets of 98 women seen at a tertiary urogynecology clinic were reviewed using proprietary software. Data were processed to estimate muscle fiber strain during Valsalva and contraction by measuring hiatal circumference and deducting bony arc length. Clinical assessment included levator palpation during maximal contraction (modified Oxford grading scale) and at rest, with tone recorded on a new six‐point scale. Analysis of imaging data was performed without knowledge of clinical data.ResultsMean age was 52.2 (range, 19–87) years and mean parity was 2.4 (range, 0–8). Mean (SD) hiatal area during contraction, rest and Valsalva was 15.4 (3.8) cm2, 18.9 (5.0) cm2 and 27.3 (8.9) cm2, respectively. There was a moderate association between strain during contraction and Oxford grade (r = 0.439, P < 0.0001), and a weak but significant association between strain during Valsalva and resting tone (r = − 0.224, P = 0.033).ConclusionsTranslabial ultrasound can be used to measure strain, a component of pubovisceral muscle elasticity, and we have validated the technique against clinical assessment. Pubovisceral strain during contraction correlates positively with Oxford grade. Pubovisceral strain during Valsalva correlates negatively with resting tone grade. This new non‐invasive ultrasound technique may be of value for assessing patients with pelvic floor dysfunction. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
First‐trimester uterine artery resistance and maternal serum concentration of asymmetric dimethylarginine
Authors: Prefumo F. , Thilaganathan B. , Whitley G. S. 
Published: February 2008

AbstractObjectiveMaternal serum levels of asymmetric dimethyl‐ arginine (ADMA), an endogenous inhibitor of endothelial nitric oxide synthase, are known to be increased in pregnant women with high‐resistance placental circulation in the second trimester. The aim of the present study was to investigate the relationship between uterine artery resistance and maternal serum ADMA concentrations in the first trimester.MethodsDoppler ultrasound examination of the maternal uterine arteries was performed at 10–14 weeks' gestation. High resistance was defined as bilateral uterine artery notches and a mean resistance index > 95th centile. Control cases were defined as those presenting with no notches and a mean resistance index < 95th centile. ADMA concentrations were measured in maternal serum.ResultsForty singleton pregnancies were examined, 21 with high uterine artery resistance and 19 controls. Three cases of pre‐eclampsia occurred, all in the high‐resistance group. The mean (SD) maternal serum ADMA concentration was 0.78 (44%) and 0.93 (56%) µmol/L in the high‐resistance and control groups, respectively (P = 0.17). There was no statistically significant correlation between maternal serum ADMA and uterine artery resistance index (ρ = − 0.15, P = 0.36).ConclusionsNo significant difference was found in maternal serum ADMA between pregnancies with first‐trimester high‐resistance uterine artery blood flow and controls. While second‐trimester circulating ADMA may have a direct link with maternal endothelial function, in the first trimester the effect of ADMA may be mainly evident at the placental level, without consequently affecting maternal circulating concentrations of the substance. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.
Identification and Functional Expression of a Δ9‐Fatty Acid Desaturase from Psychrobacter urativorans in Escherichia coli
Authors: Li Yan , Dietrich Matthias , Schmid Rolf D. , He Bingfang , Ouyang Pingkai , Urlacher Vlada B. 
Published: February 2008

AbstractThe Δ9‐fatty acid desaturase is a key enzyme in the synthesis of unsaturated fatty acids. The fatty acid composition of membrane phospholipids in Psychrobacter urativorans is characterized by a high degree of desaturation at Δ9 position. Based on CODEHOP‐mediated PCR strategy, a novel gene designated as PuFAD9, putatively encoding a Δ9‐fatty acid desaturase (PuFAD9), was isolated from P. urativorans. The gene consists of 1,455 bp and codes for 484 amino acids. Analysis of the amino acid sequence reveals three histidine clusters and a hydropathy profile, typical for membrane‐bound desaturases. Activity of the PuFAD9 protein, recombinantly expressed in Escherichia coli was confirmed by GC‐MS analysis of the cellular fatty acid composition. It was found that the ratio between palmitoleic and palmitic acid in E. coli cells heterologously expressing the PuFAD9 gene was significantly affected by IPTG induction and the growth temperature.
1,2‐Isopropylidene Glycerol Carbonate: Preparation, Characterization, and Hydrolysis
Authors: Kenar James A. , Knothe Gerhard 
Published: February 2008

AbstractUtilization of excess glycerol supplies derived from the burgeoning biodiesel industry is of major importance to the oleochemical industry as the economic viability of the biodiesel and oleochemical industries are closely linked to glycerol prices. Carbonates based on glycerol, such as glycerol carbonate, are gaining prominence due their simple preparation, interesting properties and chemistry. Herein, the synthesis, physical properties, and chemistry of an interesting glycerol‐based carbonate (4, bis[(2,2‐dimethyl‐1,3‐dioxolan‐4‐yl)methyl] carbonate; 1,2‐isopropylidene glycerol carbonate or solketal carbonate) is reported. Carbonate interchange reaction between solketal (isopropylidene glycerol) and diethyl carbonate in the presence of sodium methoxide catalyst gave solketal carbonate, 4, in 65–70% isolated yields. Carbonate 4 was characterized using Fourier transform infrared spectroscopy (FTIR), 1H and 13C nuclear magnetic resonance spectroscopy (NMR), and gas chromatography–mass spectrometry (GC/MS). The kinematic viscosity at 40 °C, refractive index, and melting point of 4 were determined to be 26.7 mm2/s, 1.4460, and below −50 °C, respectively. Using a high frequency reciprocating rig (HFRR) testing apparatus neat 4 was shown to have lubricity properties similar to fatty acid esters. Hydrolysis of the isopropylidene groups converted carbonate 4 into polyol 6, bis(2,3‐dihydroxypropyl) carbonate in good yields (84%). Carbonate polyol 6 was characterized by 1H and 13C NMR and represents a potentially novel polyol component that may be useful in the syntheses of interesting carbonate containing esters and polymers.
Factors related to the durability of a homograft monocusp valve inserted during repair of tetralogy of Fallot as based on the mid- to long-term outcomes
Authors: Yang Ji-Hyuk , Jun Tae-Gook , Park Pyo W. , Sung Kiick , Kim Wook S. , Lee Young T. , Huh June , Kang I-Seok , Lee Heung J. 
Published: February 2008

AbstractObjectivesTo maintain pulmonary valvar function subsequent to repair of tetralogy of Fallot, we have inserted a homograft monocusp when a transjunctional patch was required. In this study, we have evaluated the mid- to long-term outcomes, aiming to determine the durability of the homograft.MethodsAmong 218 repairs performed for tetralogy of Fallot between July, 1996, and June, 2005, we inserted homograft monocusps in 54 patients, 4 of whom had associated absent pulmonary valve syndrome, 3 had pulmonary valvar atresia, and 1 had an atrioventricular septal defect with common atrioventricular junction. The median body weight at surgery was 7.8 kilograms, with a range from 3.9 to 42 kilograms. The function of the monocusp valve was assessed by regular echocardiography, using the Kaplan-Meier method and the Cox regression model for statistical analyses.ResultsThere were 2 early deaths (3.7%), associated with respiratory infection. No late deaths were observed during the follow-up, which ranged from 0.3 to 120 months, with a median of 64.3 months. Freedom from valvar dysfunction was 67.2 ± 6.7% at 1 year, 37.1 ± 7.3% at 3 years, 23.8 ± 6.7% at 5 years, and 21.2 ± 6.4% at 7 years. We needed to replace the valve in 1 patient during follow-up. We found that ABO blood group incompatibility, stenosis of the pulmonary arteries, and associated absent pulmonary valve syndrome all adversely affected the function of the monocusp.ConclusionOur experiences show that insertion of a homograft monocusp can prevent pulmonary regurgitation in the early period after repair of tetralogy of Fallot, but the effects are limited in duration as degeneration progressed. We still need to determine whether this finding can improve the longer-term function of the right ventricle.
The solar and equatorial QBO influences on the stratospheric circulation during the early northern‐hemisphere winter
Authors: Kodera Kunihiko 
Published: February 2008

A case study was conducted to investigate the mechanism of how the solar cycle and the equatorial quasi‐biennial oscillation (QBO) influence the stratospheric circulation during the Northern‐Hemisphere winter.It was found that the solar and QBO influences on the stratospheric jet exist rather independently in the upper stratosphere during December. The mean‐zonal wind anomalies produced in early winter persist by deformation until late winter through wave‐mean flow interactions with planetary waves. The modulation effect of the solar influence by the QBO [Labitzke, 1987] takes place during this process.
A new approach to laser heating in high pressure mineral physics
Authors: Boehler R. , Chopelas A. 
Published: February 2008

Single crystals of olivine, forsterite, and enstatite were heated to over 2000 K between 100 and 250 kbar with a 120 W CO2‐laser in a diamond anvil cell using a hydrostatic, inert gas pressure medium. The conversion to some of their high pressure polymorphs, β‐phase, γ‐phase, perovskite, majorite, ilmenite, and clinoenstatite yielded single crystals large enough to obtain high quality Raman spectra, thus providing a quick, economic, and precise method to measure phase diagrams without pressure quenching.The phase boundaries between olivine or forsterite and β‐phase and between γ‐phase and perovskite were accurately bracketed. Our preliminary results on the latter transition are within the P‐T uncertainties of previous measurements using multi‐anvil devices [Ito and Takahashi, 1989], constraining the temperature at 670 km depth to 1900±100 K which is about 300 K higher than using their best estimate of the phase boundary.The unquenchable phase of MgSiO3‐clinopyroxene was synthesized at ∼170 kbar; Raman spectra show that this phase is of C2/c symmetry. Its stability field is between 50 and ∼165 kbar at ambient temperature.MgSiO3 perovskite was synthesized above 230 kbar and ∼2000 K. Raman spectra were measured from 75 to 470 kbar. Above 370 kbar, two modes disappear and two others change slope with pressure, suggesting a change in symmetry from Pbnm at room temperature.
The role of the equatorial electrojet in the evening ionosphere
Authors: Haerendel G. , Eccles J. V. 
Published: February 2008

This paper focuses on the role of the equatorial E region in the electrodynamics of the evening ionosphere. The influence and reaction of the electrojet current on the equatorial ionosphere at sunset is investigated using a field line integrated, one‐dimensional, electrodynamic model. The one‐dimensional, time‐varying model predicts the divergence of the horizontal current of the equatorial electrojet for a given time variation of the horizontal electric field. The negative divergence of the horizontal current during the evening hours provides a net upward current out of the equatorial E region into the integrated ionosphere of higher equatorial altitudes (and equivalent latitudes). This upward current affects the vertical electric field magnitudes and subsequent horizontal plasma drifts of the overlying ionosphere. The model allows for chemical recombination and dynamic redistribution of ionization within the electrojet region under the assumption that the profile of the ionization density along a field line is proportional to the chemical equilibrium profile. The eastward horizontal electric field and the net upward current during the 2 hours after sunset combine to lift the ionization out of the E region resulting in ionization densities less than the equilibrium values. As the ionization densities (conductivities) are reduced, the electrodynamics of the equatorial ionosphere is altered. This model of the equatorial electrojet current divergence can be used as a lower boundary to global, two‐dimensional models of the equatorial electric fields.Finally, it is proposed that the equatorial electrojet current near sunset has a significant role in the determination of the postsunset enhancement of the horizontal electric field. The electrojet region provides the best avenue for current to be channeled from the dayside to meet the vertical current demands of the F region neutral wind dynamo after sunset. The conductivity reduction in the E region due to the recombination of ionization and the plasma uplift enhances the horizontal (eastward) electric field and thereby increases the speed of the uplift. Thus the dynamic adjustment of ionization has an unstable, feedback relationship with the electric fields which may explain the night to night variability of the horizontal electric field enhancement.
Introduction to Special Section on EDGE and Related Seismic Projects, Onshore‐Offshore California
Authors: Mooney Walter D. 
Published: February 2008

The continental margins hold a special interest to Earth scientists because they mark the complex transition from oceanic to continental crust. This transition often involves a number of interacting processes, including subduction, accretion, and deformation of the oceanic lithosphere and growth and modification of the continental lithosphere, particularly the crust. The past decade has seen a great deal of progress in geophysical studies of continental margins, in large part due to the successful application of marine multi channel seismic (MCS) surveys that have provided unprecedented details on the deep structure.An opportunity arose in 1986 to augment, at a relatively modest cost, an MCS survey commissioned by the Pacific Gas and Electric Company (PG) across the central California margin. At the initiative of the Houston Area Research Center (HARC) and Rice University, funds were provided to the M CS contractor to record several additional MCS profries, and land seismographs were deployed to record the marine air gun shots and land shots prepared by the U.S. Geological Survey. Ocean bottom seismographs were deployed on two of the profiles by Oregon State University. This study constitutes the first of many profiles of opportunity completed or planned by EDGE, a National Science Foundation and industry funded consortium of institutions committed to geophysical studies of continental margins.
Thermal and barometric constraints on the intrusive and unroofing history of the Black Mountains: Implications for timing, initial dip, and kinematics of detachment faulting in the Death Valley Region, California
Authors: Holm Daniel K. , Snow J. Kent , Lux Daniel R. 
Published: February 2008

Unroofing of the Black Mountains, Death Valley, California, has resulted in the exposure of 1.7 Ga crystalline basement, late Precambrian amphibolite facies metasedimentary rocks, and a Tertiary magmatic complex. The 40Ar/39Ar cooling ages, obtained from samples collected across the entire length of the range (>55 km), combined with geobarometric results from synextensional intrusions, provide time‐depth constraints on the Miocene intrusive history and extensional unroofing of the Black Mountains. Data from the southeastern Black Mountains and adjacent Greenwater Range suggest unroofing from shallow depths between 9 and 10 Ma. To the northwest in the crystalline core of the range, biotite plateau ages from ∼13 to 6.8 Ma from rocks making up the Death Valley turtlebacks indicate a midcrustal residence (with temperatures >300°C) prior to extensional unroofing. Biotite 40Ar/39Ar ages from both Precambrian basement and Tertiary plutons reveal a diachronous cooling pattern of decreasing ages toward the northwest, subparallel to the regional extension direction. Diachronous cooling was accompanied by dike intrusion which also decreases in age toward the northwest. The cooling age pattern and geobarometric constraints in crystalline rocks of the Black Mountains suggest denudation of 10–15 km along a northwest directed detachment system, consistent with regional reconstructions of Tertiary extension and with unroofing of a northwest deepening crustal section. Mica cooling ages that deviate from the northwest younging trend are consistent with northwestward transport of rocks initially at shallower crustal levels onto deeper levels along splays of the detachment. The well‐known Amargosa chaos and perhaps the Badwater turtleback are examples of this “splaying” process.Considering the current distance of the structurally deepest samples away from moderately to steeply east tilted Tertiary strata in the southeastern Black Mountains, these data indicate an average initial dip of the detachment system of the order of 20°, similar to that determined for detachment faults in west central Arizona and southeastern California. Beginning with an initially listric geometry, a pattern of footwall unroofing accompanied by dike intrusion progresses northwestward. This pattern may be explained by a model where migration of footwall flexures occur below a scoop‐shaped hanging wall block. One consequence of this model is that gently dipping ductile fabrics developed in the middle crust steepen in the upper crust during unloading. This process resolves the low initial dips obtained here with mapping which suggests transport of the upper plate on moderately to steeply dipping surfaces in the middle and upper crust.
Compositions of synthetic augite and hypersthene coexisting at 810°C: Application to pyroxenes from lunar highlands rocks
Authors: Lindsley D. H. , King H. E. , Turnock A. C. 
Published: February 2008

Hydrothermal experiments on synthetic Ca‐Mg.‐Fe pyroxenes at 810°C and Pfluid = Ptotal = 15 kbar show that augites coexisting with orthopyroxene range in CaSiO3 content from 43 ± 1 mole percent (Fe/Fe+Mg = 0.18) to 38±1 mole percent (Fe/Fe+Mg = 0.75). Experimentally determined distribution coefficients KD = (XMgHyp · XFeAug)/(XFeHyp · XMgAug) are compatible with a constant value 0.690, but probably increase with increasing bulk Fe/Fe+Mg.If the CaSiO3 content of augites is insensitive to total pressure, these data may be used to estimate temperatures of equilibration for coexisting natural pyroxenes that are low in “non‐quadrilateral” components such as Al, Ti, Mn, and Cr. In particular, many lunar metamorphic rocks appear to have equilibrated to temperatures of 800°C and lower. These results support the view that there has been profound thermal metamorphism of the lunar crust in the interval 4.6 to approximately 4.0 G.y.
The chemical form of cosmogenic radioactive 38Cl and 39Cl in the lower stratosphere
Authors: Rowland F. S. 
Published: February 2008

The cosmogenic radioisotopes 38Cl (t ½ = 37.3 min.) and 39Cl (t ½ = 55.5 min.) are formed in the stratosphere in detectable quantities, and participate in the stratospheric chlorine cycles. The predominant expected chemical forms for these radioisotopes are ClO and/or ClONO 2 throughout most of the stratosphere. The rates for formation of HCl are sufficiently slow that most 38Cl and 39Cl atoms undergo radioactive decay before ever reacting to form HCl.The measurement of the fraction of 38Cl and 39Cl in the forms ClO and ClONO 2 , with a concurrent NO 2 measurement, can be used to measure in situ the stratospheric formation rate for ClONO 2 . Such experiments could be conducted at altitudes accessible to aircraft experiments.
Sensitivity of selected geomagnetic properties to truncation level of spherical harmonic expansions
Authors: Benton Edward R. , Estes Ronald H. , Langel Robert A. , Muth Lorant A. 
Published: February 2008

A two day selection of MAGSAT data is fit by spherical harmonic series truncated at increasing levels NF in the range 2<NF<14 to determine the extent to which the geomagnetic Gauss coefficients depend upon truncation level of the fit. The dependence is found to be concentrated in the range n<NF≲n+4 decreasing rapidly in magnitude to a few nanotesla as n increases to about 6.Several geomagnetic properties are then examined by evaluating them at various truncation levels N with NF fixed and N<NF. The spectrum of magnetic energy (outside the core and outside the earth) as determined by the NF=23 MAGSAT model MGST 1/81 is evaluated. It suggests that the crustal anomaly contribution to magnetic energy outside the core will not exceed 0.1%, when the expansion is truncated at N=8. The positions of certain contours of the geomagnetic elements on the core‐mantle boundary and their intersections needed for magnetic determination of the core motions, are examined and found to be relatively stable when N changes from 7 to 8, but to exhibit greater sensitivity for both larger and smaller values of N.This article contains supplementary material.
Pole‐strength of the Earth from MAGSAT and magnetic determination of the core radius
Authors: Voorhies Coerte V. , Benton Edward R. 
Published: February 2008

The unsigned magnetic flux linking earth's surface is evaluated numerically from a model of two days of MAGSAT data and found to be 16.054 GWb. Comparison with values calculated from earlier geomagnetic field models dating back to 1930 reveals a smooth, monotonic and recently accelerating decrease in earth's pole‐strenth at a fifty year average rate of 8.3 MWb/year or 0.052% per year.Hide's magnetic technique for finding the radius of earth's electrically conducting core is tested in two ways. Main field models for 1960 and 1965 are first extrapolated downward through the nearly insulating mantle and then separately compared to equivalent extrapolated models of MAGSAT data. For each of these two earlier epochs, the unsigned flux is found to equal the MAGSAT value at a unique radius which is within 2% of the seismic core radius.Main field models at the earlier epochs 1950, 1940, and 1930 are then derived from the 1960 main field, secular variation and secular acceleration coefficients of the GSFC 12/66 model. Truncation at degree N=8 and comparison with an equivalent MAGSAT model again yields magnetic values of the core radius within 2% of the seismic value. These results support the customary geophysical approximations that the mantle is nearly a perfect insulator and the core a perfect conductor on the decade time scale.