bluuebunny/crossref_metadata_2025_split huggingface dataset:
Plant sterols lower LDL cholesterol without improving endothelial function in prepubertal children with familial hypercholesterolaemia
Authors: De Jongh S. , Vissers M. N. , Rol P. , Bakker H. D. , Kastelein J. J. P. , Stroes E. S. G. 
Published: September 2003

AbstractIn adults with familial hypercholesterolaemia (FH), cholesterol lowering with statins has been shown to improve the endothelial function, a hallmark of early atherogenesis. Currently, therapeutic options for treating high cholesterol levels in FH children are limited. Plant sterols safely and effectively reduce serum cholesterol concentrations by inhibiting cholesterol absorption. Therefore, we evaluated the effect of plant sterols on cholesterol and vascular function in prepubertal children with FH. We included 41 children (5–12 years old) with FH in a double‐blind crossover trial using spreads containing 2.3 g of plant sterols (mainly sitosterol and campesterol) per 15 g spread and a placebo spread for a 4‐week period, separated by a 6‐week washout period. Lipid levels and endothelial function were assessed after both 4‐week treatment periods. Endothelial function was assessed as flow‐mediated dilation (FMD) of the brachial artery using a wall tracking system. Data were compared to those of 20 healthy controls. Intake of 2.3 g plant sterols per day decreased total cholesterol (‐11%) and low‐density cholesterol (‐14%) as compared to placebo spread in FH children. FH children treated with placebo spread were characterized by an impaired FMD compared to healthy control children (7.2 %± 3.4% versus 10.1%±4.2%, p < 0.005). However, the reduction of LDL in FH children did not improve FMD (placebo: 7.2% ± 3.4% versus plant sterols: 7.7% ± 4.1%). In conclusion, the present study shows a clear reduction of LDL cholesterol by plant sterol treatment. However, short‐term plant sterol treatment does not improve the endothelial function in FH children.
Effect of skeletal muscle decorin on collagen fibrillogenesis in vitro
Authors: NISHIMURA Takanori , TANEICHI Ayaka , WAKAMATSU Jun‐ichi , HATTORI Akihito 
Published: September 2003

ABSTRACTThe effect of skeletal muscle decorin on collagen fibrillogenesis was investigated, in order to provide background for understanding the functions of decorin in skeletal muscle. The self‐assembly of type I and III collagen with the addition of decorin or the core protein of decorin from bovine neonatal skeletal muscle was monitored using a spectrophotmeter. Time course changes in the absorbance of collagen solutions showed typical sigmoidal curves composed of three phases. The time of the initial phase was not different between the collagen solution with decorin and that without decorin. The increase rate of the absorbance in the second phase decreased with concentration of decorin added in collagen solutions. Similar effects on fibrillogenesis of type I and III collagens were observed when the core protein of decorin was added in collagen solutions. These results suggest that regulation of collagen fibrillogenesis by decorin depends on its core protein. The networks of reconstructed collagen fibrils with decorin were looser than those without decorin. Bovine skeletal muscle decorin could participate in the regulation of collagen fibrillogenesis and in the arrangement of collagen fibrils in the intramuscular connective tissue.
Hydrothermal and resedimented origins of the precursor sediments to banded iron formation: sedimentological evidence from the Early Palaeoproterozoic Brockman Supersequence of Western Australia
Authors: Krapež Bryan , Barley Mark E. , Pickard April L. 
Published: September 2003

AbstractThe Early Palaeoproterozoic Brockman Supersequence comprises banded iron formation (BIF), bedded chert, limestone, mudrock, sandstone, breccia, tuffaceous mudstone, ashfall tuff and, in sections not reported here, basalt and rhyolite. Density current rhythms are preserved in sandstones, mudrocks, tuffaceous mudstones and limestones. Relics of similar rhythms in BIF imply that its precursor sediments were also deposited by density currents. Hemipelagic deposits are siliciclastic or mixed siliciclastic–volcaniclastic mudstones. Bedded chert, chert nodules and the chert matrix of BIF preserve evidence for formation by diagenetic replacement. For bedded chert (and chert nodules), silica replacement occurred before compaction close to or at the sediment–water interface, indicating that it is siliceous hardground. The chert matrix of BIF formed during compaction but before burial metamorphism. Original sediments were resedimented from two sources: (1) limestone, mudrock, sandstone, breccia and tuffaceous mudstone from a shelf; and (2) BIF from within the basin realm. Shelf sediments were resedimented to basin‐floor fans during third‐order lowstands. The precursor sediments to BIF are interpreted to have been granular hydrothermal muds, composed of iron‐rich smectite and particles of iron oxyhydroxide and siderite that were deposited on the flanks of submarine volcanoes and resedimented by density currents. Resedimentation occurred by either bottom currents or gravity‐driven turbidity currents, and the resulting sediment bodies may have been contourite drifts. The concept that BIF records high‐frequency alternating precipitation from ambient sea water of iron minerals and silica is negated by this study. Instead, it is postulated that the precursor sediments to BIF originated in much the same way as modern Red Sea hydrothermal iron oxide deposits, implying that at least the particles of iron oxyhydroxide originated from the oxidation of vent fluids by sea water. Several orders of cyclicity in basin filling establish a relationship between rising to high sea levels, episodic sea‐floor hydrothermal activity and BIF that is reminiscent of the link between eustacy and spreading‐ridge pulses.
Inter- and Intraclonal Diversity of the
Pseudomonas aeruginosa
Proteome Manifests within the Secretome
Authors: Wehmhöner Dirk , Häussler Susanne , Tümmler Burkhard , Jänsch Lothar , Bredenbruch Florian , Wehland Jürgen , Steinmetz Ivo 
Published: September 2003

ABSTRACT

The proteomes of cultured
Pseudomonas aeruginosa
isolates from chronically infected cystic fibrosis (CF) lungs were compared by using genetically divergent clones and isogenic morphotypes of one strain. Cellular extracts gave very similar protein patterns in two-dimensional gels, suggesting that the conserved species-specific core genome encodes proteins that are expressed under standard culture conditions in vitro. In contrast, the protein profiles of extracts of culture supernatants were dependent on the growth phase, and there were significant differences between clones. The profiles also varied within clonally related morphotypes from one CF patient, including a hyperpiliated small-colony variant. Mass spectrometry revealed that this variant overexpressed proteins secreted by the type I secretion system (including proteins involved in iron acquisition) and by the type III secretion system. Furthermore, the proteins in the supernatant extracts from the small-colony variant which were recognized by sera from different CF patients varied greatly. We concluded that the secretome expression is a sensitive measure of
P. aeruginosa
strain variation.
A Novel Outer Membrane Protein, Wzi, Is Involved in Surface Assembly of theEscherichia coliK30 Group 1 Capsule
Authors: Rahn Andrea , Beis Kostantinos , Naismith James H. , Whitfield Chris 
Published: September 2003

ABSTRACTEscherichia coligroup 1 K antigens form a tightly associated capsule structure on the cell surface. Although the general features of the early steps in capsular polysaccharide biosynthesis have been described, little is known about the later stages that culminate in assembly of a capsular structure on the cell surface. Group 1 capsule biosynthesis gene clusters (cps) inE. coliandKlebsiella pneumoniaeinclude a conserved open reading frame,wzi. Thewzigene is the first of a block of four conserved genes (wzi-wza-wzb-wzc) found in all group 1 K-antigen serotypes. Unlikewza,wzb, andwzchomologs that are found in gene clusters responsible for production of exopolysaccharides (i.e., predominantly cell-free polymer) in a range of bacteria,wziis found only in systems that assemble capsular polysaccharides. The predicted Wzi protein shows no similarity to any other known proteins in the databases, but computer analysis of Wzi predicted a cleavable signal sequence. Wzi was expressed with a C-terminal hexahistidine tag, purified, and used for the production of specific antibodies that facilitated localization of Wzi to the outer membrane. Circular dichroism spectroscopy indicates that Wzi consists primarily of a β-barrel structure, and dynamic light scattering studies established that the protein behaves as a monomer in solution. A nonpolarwzichromosomal mutant retained a mucoid phenotype and remained sensitive to lysis by a K30-specific bacteriophage. However, the mutant showed a significant reduction in cell-bound polymer, with a corresponding increase in cell-free material. Furthermore, examination of the mutant by electron microscopy showed that it lacked a coherent capsule structure. It is proposed that the Wzi protein plays a late role in capsule assembly, perhaps in the process that links high-molecular-weight capsule to the cell surface.
L (X-ray) cross sections of heavy elements excited by 15.20 keV photons
Authors: Saad M 
Published: September 2003

In this work Lα and Lβ X-ray fluorescence cross sections and their relative intensities ILβ  / ILα were measured for the elements La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb, and Lu using a photon energy of 15.20 keV. Reasonable agreement is obtained between the present experimental results and the theoretically calculated values of L X-ray cross sections and their relative intensities. PACS Nos.: 32.30.Rj, 32.50.td
Heat transfer over a stretching surface with internal heat generation
Authors: Elbashbeshy E MA , Bazid M AA 
Published: September 2003

Heat transfer over a stretching surface with internal heat generation or absorption is examined. The surface is moving with a power-law velocity distribution. The effect of various governing parameters, such as the Prandtl number, the velocity exponent, and the heat-source/sink parameter on the velocity profiles, temperature profiles, and rate of heat transfer are analyzed. PACS No.: 44.20.tb
Natural-frequency concept utilized in remote probing of the earth
Authors: Bishay S T , Abo-Seida O M , Sami G M 
Published: September 2003

The complete time-domain fields due to a vertical magnetic dipole on the surface of a two-layered earth model are derived in an analytical form using the natural-frequency concept. In these expressions, the displacement currents in the earth's layers are taken into consideration. The step responses of the induced voltage in a horizontal receiving loop is found to have definite diagnostic features for the ground beneath. These features are demonstrated by numerical results and shown by figures. The clear distinction between the step response of the homogeneous and the two-layered ground suggests that this response can be used for the detection of the stratification. PACS Nos.: 41.20.Jb, 42.25.Bs, 42.25.Gy, 44.05.+e
Dynamical quantization and classical limit
Authors: Bolivar A O 
Published: September 2003

We have worked out a quantization method directly from classical dynamics without using Hamiltonian and Lagrangian functions; we call it dynamical quantization. The present article compares such a method with the Dirac and Feynman quantization procedures and also verifies the logical consistence of the dynamical quantization calculating the classical limit of a Brownian particle, for example. PACS Nos.: 03.65.w, 05.30.d, 05.40.+j, 52.65.Ff
Electromagnetic scattering by a lossy dielectric-coated elliptic cylinder
Authors: Hamid A -K , Hussein M I 
Published: September 2003

The problem of electromagnetic wave scattering by a lossy dielectric-coated elliptic cylinder is analyzed using elliptic waves expressed in terms of complex Mathieu functions. Numerical results are obtained for the scattered field in the far zone for different axial ratios, lossy dielectric constants, and angles of incidence. The numerical results show a significant change in backscattering echo due to the lossy dielectric coating. PACS No.: 42.25.Fx
The effect of an axial electric field on the nonlinear stability between two uniform stream flows of finitely conducting cylinders
Authors: Elhefnawy Abdel Raouf F , Moatimid Galal M , Khalil Elcoot Abd Elmonem 
Published: September 2003

Weakly nonlinear streaming instability of two conducting fluids with an interface is presented for cylinders of circular cross section. The two fluids are subjected to a uniform axial electric field. Gravitational effects are neglected. The method of multiple scale perturbation is used to obtain a dispersion relation for the first-order problem and two nonlinear Schrödinger equations for the higher orders. The nonlinear Schrödinger equation, generally, describes the competition between nonlinearity and a linear dispersion relation. One of these equations is used to determine the nonlinear cutoff electric field separating stable and unstable disturbances, while the other is used to analyze the stability of the system. The stability criterion is expressed theoretically in terms of various parameters of the problem. Stability diagrams are obtained for different sets of physical parameters. New instability regions in the parameter space, which appear due to nonlinear effects, are indicated. PACS Nos.: 47.20, 47.55.C, 47.65
Forced gravity waves in two-layered fluids with the upper fluid having a free surface
Authors: Sherief H H , Faltas M S , Saad E I 
Published: September 2003

The steady-gravity wave motion is considered for two immiscible layers of incompressible and nonviscous fluids in the presence of a porous wave maker immersed vertically in the two fluids, the upper fluid having a free surface and the lower fluid is of infinite depth. The boundary value problem for the velocity potentials is solved using Taylor's assumption on the wave maker. Also the scattering of a harmonic wave incident normally to the wave maker is considered and the reflection and transmission coefficients are obtained. The case when the lower fluid is of finite depth is also considered. The results are plotted for different values of porosity and different values of the density ratio. PACS Nos.: 47.35.+i, 47.55.Hd, 47.55.Mh
The effect of thermal relaxation time on a electrohydrodynamic viscoelastic fluid layer heated from below
Authors: Othman M IA , Zaki S A 
Published: September 2003

The problem of the onset of stability in a horizontal layer of a viscoelastic dielectric liquid with one relaxation time heated from below under the action of a vertical ac electric field is analyzed. Linear stability theory is used to derive an eigenvalue system of order eight and an exact eigenvalue equation for a neutral instability is obtained. Under somewhat artificial boundary conditions, this equation can be solved exactly to yield the required eigenvalue relationship from which various critical values are determined in detail. The critical Rayleigh number and wave number for the onset of instability are presented graphically as functions of the Grashof number for various values of the Prandtl number and one relaxation time. A comparison is made with the results obtained in the absence of an electric field. PACS No.: 47.27.T
A high-speed-modulated retro-reflector for lasers using an acousto-optic modulator
Authors: Spirou G , Yavin I , Weel M , Vorozcovs A , Kumarakrishnan A , Battle P R , Swanson R C 
Published: September 2003

We have used an acousto-optic modulator (AOM) to impose a frequency-modulated signal on an incident laser beam. The incident laser beam is focussed into the AOM where it undergoes Bragg diffraction and is then retro-reflected. The diffracted beam is also retro-reflected so that it is diffracted again by the AOM and overlaps the incident beam. The overlapped beams are frequency shifted with respect to each other. These features allow us to detect the frequency-modulated signal with high signal-to-noise ratio using heterodyne detection. Since the optical setup is simple and can be made very compact, this device may be ideal for certain forms of high-speed, free-space optical communication. We demonstrate a 1 MHz data transmission rate in the Bragg regime. We measured the acceptance angle of the device and find that it is limited only by the divergence of the focussed laser beam and the divergence of the acoustic waves in the AOM crystal. We have also studied the range of acoustic frequencies and drive power of the AOM, for which the retro-reflected beam can be detected with adequate signal to noise. PACS Nos.: 42.60.V, 42.62.Cf, 42.62.Fi, 42.79.Sz, 42.79.Hp
Calculation of the transfer efficiency between dual magneto-optical traps and simulation of a Ioffe trap for BoseEinstein condensation
Authors: Yavin I , Mikaelian T , Kumarakrishnan A 
Published: September 2003

We consider the problem of transferring a cold atomic cloud from a low-vacuum chamber to an ultra-high-vacuum (UHV) chamber, where it can be recaptured and cooled to the transition temperature for BoseEinstein condensation (BEC). Our calculation assumes an initial MaxwellBoltzmann velocity distribution for the thermal cloud and a Gaussian spatial density distribution that is characteristic of magneto-optical traps (MOTs). Using a coordinate transformation we find the density of the recaptured atomic cloud as a function of time. This allows us to investigate the effect of experimental parameters on the transfer efficiency. These parameters include the distance of separation between the two chambers, the duration of the initial on-resonant laser used to push the thermal cloud, and the initial cloud temperature. We also present numerical simulations of the magnetic field due to a simplified IoffePritchard (IP) trap that has recently been used to obtain BEC using laser-cooling techniques. This trap converts a quadrupole magnetic field into an IP configuration using the magnetic field of a conical solenoid placed orthogonally to the axis of symmetry of a pair of quadrupole coils. Our results are suitable for small experimental groups interested in achieving BEC. PACS No.: 03.75
A high-speed retro-reflector for free-space communication based on electro-optic phase modulation
Authors: Mikaelian T , Weel M , Kumarakrishnan A , Battle P R , Swanson R C 
Published: September 2003

We demonstrate that an electro-optic phase modulator (EOM) can be used as a constituent of a corner-cube-based modulated high-speed retro-reflector. We performed experiments to investigate the efficiency of the phase modulation produced by an EOM as a function of the angle of a laser beam incident on it. Our experiments demonstrate that the field of view of the EOM is determined by its dimensions and the diameter of the laser beam. This suggests that the device may be suitable for applications involving high-speed (GHz), free-space communication. In these applications, the retro-reflector can be mounted on a moving platform such as a satellite. We find that it is possible to detect the retro-reflected signal with an adequate signal-to-noise ratio using heterodyne detection. We also discuss some practical considerations necessary for the implementation of such a device. PACS Nos.: 42.60.V, 42.62.Cf, 42.62.Fi, 42.79.Sz, 42.79.Hp
Identification of semiclassical chaos in two-dimensional PT-symmetric systems
Authors: Nanayakkara Asiri , Abayaratne Chula 
Published: September 2003

Identification of regular and chaotic motions of two-dimensional PT-symmetric complex systems was investigated. New definitions have been introduced to study properties of trajectories in complex phase space. Projections of these trajectories on complex x- and y-planes, Lyapunov exponents, and surfaces of section have been used for identifying regular and irregular (chaotic) motions in complex phase space. Quantum level spacing distributions of these systems have also been calculated for finding out the connection between regular and irregular states with standard distributions such as Poisson and Wigner distributions. It has been found that the PT-symmetric complex systems behave in the same way as the real systems. PACS No.: 05.45.Ac
Unsteady flow of a dusty conducting non-Newtonian fluid through a pipe
Authors: Attia H A 
Published: September 2003

In this paper, the unsteady flow of a dusty viscous incompressible electrically conducting non-Newtonian power-law fluid through a circular pipe is investigated. A constant pressure gradient in the axial direction and a uniform magnetic field directed perpendicular to the flow direction are applied. The particle phase is assumed to behave as a viscous fluid. A numerical solution is obtained for the governing nonlinear momentum equations using finite differences. The effects of the magnetic-field parameter Ha, the non-Newtonian fluid characteristics (the flow index n), and the particle-phase viscosity β on the transient behavior of the velocity, volumetric flow rates, and skin friction coefficients of both fluid and particle phases are studied. It is found that all the flow parameters for both phases decrease as the magnetic field increases or the flow index decreases. On the other hand, increasing the particle-phase viscosity increases the skin friction of the particle phase, but decreases the other flow parameters. PACS No.: 47.50.+d
Comment on "A simple explanation of the nonappearance of physical gluons and quarks"
Authors: Aste Andreas 
Published: September 2003

In a recent paper by Johan Hansson it is claimed that the nonappearance of quarks and gluons as physical particles is an automatic result of the non-Abelian nature of the color interaction in quantum chromodynamics. It is shown that the arguments given by Hansson are insufficient to support his claim by giving simple counter arguments. PACS No.: 11.10.z
Analytical formulas for the Stark effect on intensity of hydrogen radiation lines
Authors: Kamenski A A , Ovsiannikov V D 
Published: September 2003

A regular method for deriving the consecutive terms of a series in powers of field strength F for the intensities of hydrogen radiation lines is presented both analytically and numerically. Specific modification of the perturbation theory for degenerate states and the Sturm-series expansion for the completely reduced CoulombGreen function in parabolic coordinates are used to derive simple analytical formulas for matrix elements and the intensities of the radiation transitions between circular states. Particular cases of transitions between the closest Rydberg levels are presented and discussed in detail. Analytical expressions are also derived for the quadrupole matrix elements, which may contribute to the probability of σ-transitions with the selection rule for the magnetic quantum number Δm = ±1 and determine the probability of the dipole-forbidden radiation transitions between Stark levels with Δm = ±2. PACS Nos.: 32.60.+i, 32.70.n, 32.70.Fw