Reduction Of Radius Research Articles

Bifurcation analysis of a model for atherosclerotic plaque evolution

We analyze two ordinary differential equation (ODE) models for atherosclerosis. The ODE models describe long time evolution of plaques in arteries. We show how the dynamics of the first atherosclerosis model (model A) can be understood using codimension-two bifurcation analysis. The Low-Density Lipoprotein (LDL) intake parameter (d) is the first control parameter and the second control parameter is either taken to be the conversion rate of macrophages (b) or the wall shear stress (σ). Our analysis reveals that in both cases a Bogdanov–Takens (BT) point acts as an organizing center. The bifurcation diagrams are calculated partly analytically and to a large extent numerically using AUTO07 and MATCONT. The bifurcation curves show that the concentration of LDL in the plaque as well as the monocyte and the macrophage concentrations exhibit oscillations for a certain range of values of the control parameters. Moreover, we find that there are threshold values for both the cholesterol intake rate dcrit and the conversion rate of the macrophages bcrit, which depend on the values of other parameters, above which the plaque volume increases with time. It is found that larger conversion rates of macrophages lower the threshold value of cholesterol intake and vice versa. We further argue that the dynamics for model A can still be discerned in the second model (model B) in which the slow evolution of the radius of the artery is coupled self-consistently to changes in the plaque volume. The very slow evolution of the radius of the artery compared to the other processes makes it possible to use a slow manifold approximation to study the dynamics in this case. We find that in this case the model predicts that the concentrations of the plaque constituents may go through a period of oscillations before the radius of the artery will start to decrease. These oscillations hence act as a precursor for the reduction of the artery radius by plaque growth.

Nanoparticles for Enhanced Oil Recovery: Phase Transition of Aluminum-Cross-Linked Partially Hydrolyzed Polyacrylamide under Low-Salinity Conditions by Rheology and Nuclear Magnetic Resonance

There is booming interest in the application of nanoparticles for enhanced oil recovery. In this work, a polymer nanoparticle that is generated by cross-linking a high-molecular weight partially hydrolyzed polyacrylamide with aluminum(III) and known as linked polymer solution (LPS) has been studied. The size and conformational state of LPS particles are influenced by the concentration of Al(III). To the best our knowledge, there is no current established method for determining the conformational state, i.e., single coiled particle, coil aggregates, or gel, for a polymer solution with a high molecular weight (>10 × 106 Da) and a low concentration (<1000 ppm). In this work, therefore, the phase transition of LPS is investigated by employing two-dimensional 1H–1H nuclear magnetic resonance (nuclear Overhauser effect spectroscopy and diffusion ordered spectroscopy), UV–visible spectroscopy, and oscillatory rheological methods. Each method is limited to determining the conformational state; however, the combined methods provided a consistent tool for mapping various interactions regarding the conformational changes of LPS as a function of Al(III) concentration. The results of our study revealed that the phase transition is a stepwise process; the transition from a random polymer coil to structured coils (intramolecular cross-linking) was observed by reduction of the hydrodynamic radius and an increase in the rate of diffusion, followed by coil aggregates as a function of Al3+ concentration. Ultimately, networked weak gels are formed by coil aggregates (intermolecular cross-linking) above the threshold concentration.

Golf Club Deflection Characteristics as a Function of the Swing Hub Path

This study investigated the relationships between golfer hub path trajectories and interaction kinetics, and club behavior. An equation of motion describing a flexible golf club system was derived and solved to yield time and club position deflection behavior during the downswing. This equation was applied to three diverse subjects whose kinematic and kinetic information was used to drive the simulation. It was determined that there is a relationship between the timing of the maximum interaction torque and the increase in normal force applied to the club and club head deflections. Also, it appears that there is a correlation between degree of radius reduction directly before impact and shaft deflection behavior. The timing of both torque and normal force are directly related to changes in hub path radius thus the effect of hub path geometry on club deflection behavior is secondary. Based upon these findings, a method for fitting shafts to specific swing characteristics was developed that optimized predicted carry distance. These results are based upon limited subjects.

Bean-Shaped Spherical Tokamak Equilibrium With Ergodic Limiter

Equilibrium simulations of a spherical tokamak (ST) with a bean-shaped plasma in rail limiter geometry are presented for the first time. Preliminary results in a not fully self-consistent scenario show this equilibrium is possible and, compared with the more usual ST rail limiter D-shaped geometry, retain consistently the same kinetic storage energy. The related parameters such as volume-averaged beta increase by 17% due to pure geometric effects, i.e., the increase of plasma major radius (10%), which then increases the aspect ratio (1.4-1.6) due to the simultaneous reduction of plasma minor radius (9%), while the elongation increases (1.2-1.3). The plasma volume is virtually the same but the plasma triangularity increases substantially (0.32-0.45) thus favoring beta limits because of shaping. These results have been obtained after a careful pressure tailoring by fixing the plasma outboard within a 3% error. This unique bean-shaped equilibrium can be attained simultaneously (but independently) setting an edge localized ergodization as observed via a Poincaré mapping, using a low level of nonresonant perturbation to the plasma current ( ~ 2%). This combination can theoretically lead to a higher beta limit ST plasma with different thermal power loads distribution, which is an interesting area of study for larger devices.

Pressure‐Induced Intersite BiM (M=Ru, Ir) Valence Transitions in Hexagonal Perovskites

Pressure-induced charge transfer from Bi to Ir/Ru is observed in the hexagonal perovskites Ba(3+n)BiM(2+n)O(9+3n) (n=0,1; M=Ir,Ru). These compounds show first-order, circa 1% volume contractions at room temperature above 5 GPa, which are due to the large reduction in the effective ionic radius of Bi when the 6s shell is emptied on oxidation, compared to the relatively negligible effect of reduction on the radii of Ir or Ru. They are the first such transitions involving 4d and 5d compounds, and they double the total number of cases known. Ab initio calculations suggest that magnetic interactions through very short (ca. 2.6 Å) M-M bonds contribute to the finely balanced nature of their electronic states.

A new AMBER-compatible force field parameter set for alkanes

We present a new force field parameter set for simulating alkanes. Its functional form and parameters are chosen to make it directly compatible with the AMBER94/99/12 family of force fields implemented in the available software. The proposed parameterization enables universal description of both the conformational and thermodynamic properties of linear, branched, and cyclic alkanes. Such unification is achieved by using two essential principles: (1) reduction of the Lennard-Jones radius for all sp3 carbons to 1.75Å; (2) separate optimization of Lennard-Jones well depths for carbons with different degree of substitution. The new parameter set may prove to be optimal for description of alkyl residues in a broad range of biomolecules, from amino acids to lipids with their extended linear tails.

Optimization of speeded-up robust feature algorithm for hardware implementation

Speeded-Up Robust Feature (SURF) is a widely-used robust local gradient feature detection and description algorithm. The algorithm itself can be implemented easily on general-purpose processors. However, the software implementation of SURF cannot achieve a performance high enough to meet the practical real-time requirements. And what is more, the huge data storage and the floating point operation of SURF algorithm make it hard and onerous to design and verify corresponding hardware implementation. This paper customized a SURF algorithm for hardware implementation, which combined several optimization methods in previous literature and three approaches (named Word Length Reduction (WLR), Low Bits Abandon(LBA), and Sampling Radius Reduction (SRR)). The computation operations of the simplified and optimized SURF (P-SURF) were reduced by 50% compared with the original SURF. At the same time, the Recall and Precision of the SURF feature descriptor are only dropped by 0.31 on average in the typical testing set, which are within an acceptable accuracy range. P-SURF has been implemented on hardware using TSMC 65 nm process, and the architecture of the whole system mainly contains four modules, including Integral Image Generator, IPoint Detector, IPoint Orientation Assigner, and IPoint Feature Vector Extractor. The chip size is 3.4 × 4 mm2. The power usage is less than 220mW according to the Synopsys Prime time while extracting IPoints in a video input of VGA (640 × 480) 172 fps operating at 200 MHz. The performance is better than the results reported in literature.

Short-term Changes in Tear Volume After Blepharoptosis Repair

The aim was to evaluate tear volume change by using videomeniscometry before and after blepharoptosis surgery. Fifty-nine eyes of 36 patients with blepharoptosis without lacrimal duct obstruction or other eyelid diseases were examined. All the patients underwent levator advancement, and the tear volume was evaluated preoperatively and 1.5 months postoperatively. The margin reflex distance-1 was determined from photographs, and the tear volume was determined by the measurement of tear meniscus radius using videomeniscometry. The mean margin reflex distance-1 was significantly increased after performing a blepharoptosis surgery (0.13 ± 1.13 mm preoperatively vs. 3.18 ± 0.85 mm postoperatively, P < 0.001). The average tear meniscus radius was significantly decreased (0.31 ± 0.16 mm preoperatively vs. 0.23 ± 0.08 mm postoperatively, P < 0.001). A postoperative reduction in the tear meniscus radius was noted in 46 eyes (78%) of 31 patients, and no reduction was noted in 13 eyes (22%) of 12 patients. Preoperative higher tear meniscus radius values were more likely to be decreased (P < 0.01). The tear volume was decreased after the blepharoptosis surgery was performed, especially for an initially high tear volume.

Signal Coverage Estimation Model for Microcellular Network Propagation

This paper presents the signal coverage estimation for microcellular network propagation. Firstly, this work presents the techniques for eliminating or reducing the drawbacks like limited service capability, high blocking probabilities and inefficient frequency spectrum utilization that negatively affect the signal network coverage in land to mobile networks and macro cellular networks due to wider or larger cell radii. Secondly, the methodology of improving signal coverage under different morphological conditions is also presented, and this was achieved by creating a communication path between two remote base stations under different morphological conditions. The signal strength received in all the different morphologies are then estimated for different cell radii. Thirdly, the results of the estimated signal strength in all the morphologies are also presented in this paper. The results show that the signal strength received in urban morphology is the strongest because, the distance between the cell radii of the base stations are closer than sub-urban and rural morphologies. Lastly, this research also reveals the importance of using signal strength measurements, path loss and cell radius to determine signal coverage estimation for micro cellular network propagation. Finally,it shows that the reduction of the cell radius and path loss will automatically increase the received signal strength, which helps in achieving the accuracy of signal coverage prediction of microcellular network under different morphologies.

Heat and Mass Transfer of Droplet Vacuum Freezing Process Based on Dynamic Mesh

A numerical simulation using dynamic mesh method by COMSOL has been developed to model heat and mass transfer during vacuum freezing by evaporation of a single droplet. The initial droplet diameter, initial droplet temperature, and vacuum chamber pressure effect are studied. The surface and center temperature curve was predicted to show the effect. The mass transfer rate and radius displacement were also calculated. The results show the dynamic mesh shows well the freezing process with the radius reduction of droplet. The initial droplet diameter, initial droplet temperature, and vacuum pressure have obvious effect on freezing process. The total freezing time is about 200 s, 300 s, and 400 s for droplet diameter 7.5 mm, 10.5 mm, and 12.5 mm, respectively. The vacuum pressure less than 200 Pa is enough for the less time to freezing the droplet, that is, the key point in freezing time. The initial droplet temperature has obvious effect on freezing but little effect on freezing temperature.

Characterization of crystallite size, dislocation characteristics and stacking faults in nanostructured mechanically alloyed Cu–Fe system using an advanced X-ray diffraction analysis method

Developments in the synthesis of nanostructured materials have expanded the need for appropriate characterization methods. The aim of this work is to apply new X-ray diffraction analysis methods for simultaneous investigation of various microstructural characteristics. For this purpose, the structure of mechanically alloyed Cu–Fe system with three compositions of 30wt%, 50% and 70% of iron was studied. By applying the modified Williamson-Hall method, the type of dislocations in the FCC phase is distinguished. Afterwards by modification of previous XRD analysis methods, the proportion of edge/screw dislocations was characterized. Moreover, the outer cut-off radius, the density and energy of dislocations were calculated as a function of the composition and the milling time. On the other hand, using the extended convolutional multiple whole profile fitting procedure, the variations in the crystallite size and size distribution of FCC and BCC phases were studied. Finally, the stacking fault probability was calculated in different milled samples. It is revealed that smaller steady state crystallite size of samples with higher Fe content, is relevant to reduction of the outer cut-off radius of dislocation. On the other hand, the density of dislocations and stacking faults increased continuously up to 96h of milling.

Non-magnetic impurities to induce magnetism in α-PbO crystal structure

A new route to d0 magnetism is established with the help of the first-principles methods. Non-magnetic elements in groups 13 and 14 of the periodic table are found to act as the magnetic centers upon embedding in polycrystalline α-PbO structure. Thus, the local magnetic moment is generated on the impurity site ( and for elements in groups 13 and 14, respectively) due to p orbitals partially filled with electrons whose on-site spin ordering is governed by the first Hund's rule. The magnetic interactions between impurities are controlled by occupation of the p orbitals so that antiferromagnetic (AFM) ordering occurs between impurities of while ferromagnetic (FM) ordering occurs between impurities possessing . With respect to the strength of the magnetic interactions, the atomic radius of impurity is found to be a key element to tune the wave function tails of localized electrons: with the reduction of the atomic radius, the on-site stability of the spin-polarized state grows while losing in the long-range order interactions. However, it has been shown that a suppression of the long-range order interactions can be compensated by higher impurity concentration that is allowed by the shift of the solubility limit to higher magnitude.

Intra‐Chain Photodimerization of Pendant Anthracene Units as an Efficient Route to Single‐Chain Nanoparticle Fabrication

An efficient route to architecturally defined, sub-20 nm soft nanoparticles fabricated from single polymer chains via intramolecular photodimerization of pendant anthracene units is presented. Photodimerization is confirmed by the disappearance of the characteristic anthracene π-π* absorption peak at ≈ 360 nm measured by UV-vis spectroscopy. Size exclusion chromatography (SEC) with UV, multi-angle light scattering (MALS), and viscometric detection confirms that as photodimers form, the chains fold to form nanoparticles, demonstrated by shifts in the SEC traces to longer retention times as a function of increased irradiation time. These shifts indicate a reduction in hydrodynamic radius, corroborated and quantified by viscometric data. MALS detector traces reveal the presence of a small amount of chain-chain coupling during this process, but confirm that this is primarily a single-chain phenomenon. Electron microscopy provides visual confirmation of nanoparticle formation.

Spiral surface plasmon modes on uniform and tapered metallic nanorods

Spiral surface plasmon (SSP) modes on uniform and tapered silver nanorods are explored by performing both simulations and theoretical analyses. On a uniform nanorod with a radius equal to 240&#xA0;nm, the SSP modes can be generated by linearly superposed higher-order HE1 and HE2 eigenmodes. Both the single- and triple-stranded SSP modes are produced by controlling the relative rotation direction of the two component modes. On a tapered nanorod, the spiral pitch of the SSP mode decreases with the reduction of nanorod radius. However, the field energy density along the nanorod axis increases to a maximum value and then falls.

Impact of Sectorization/Vehicular Traffic on Minimum Cell Size for Information Capacity Increase in Cellular Systems

In this paper results of mathematical analysis sup-ported by simulation are used to study the impact of sectorization/vehicular traffic on the theoretical limit for cell size radius reduction in cellular wireless communication systems. Information capacity approach is used for the analysis. Attention is given to the active co-channel interfering cells. Because at carrier frequencies greater than 2 GHz, co-channel interfering cells beyond the first tier becomes dominant as the cell size radius reduces. Results show that for sectorized cellular wireless communication system operating at carrier frequency greater than 2 GHz and having smaller cell size radius in a traffic environment the second tier co-channel interference still becomes active. This causes a decrease in the information capacity of the cellular wireless system. For example for a heavy vehicular traffic environment, at a carrier frequency fC = 15.75 GHz, basic path loss exponent α = 2 and cell radius R = 100, 300 and 500 m for a six sector cellular the decrease in information capacity, because of interference from the second tier was 5.47, 3.36 and 2.78%.

Free volumes studies in Thymoquinone and Carvone β-cyclodextrin nanoparticles by positron annihilation lifetime spectroscopy

Positron annihilation lifetime spectroscopy is used to study free volume in β-cyclodextrin with the encapsulation of thymoquinone and S-carvone, in samples covering the guest to host fraction range from 1:0.1 to 1:1. The results clearly indicate the presence of long lifetime components related to Ps-formation. Although the behavior of the two guests is different, in both cases the results indicate the formation of 1:1 cyclodextrin inclusion compounds. Data show that the addition of carvone to β-cyclodextrin results in a decrease of the o-Ps lifetime corresponding to a reduction of the average radius of cavities from 2.41 Å to 2.29 Å, whereas the addition of thymoquine decreases the radius from 2.57 Å to 2.35 Å. In turn, the intensity varied from 20.55 to 19.20% and from 20.83 to 0.41%, respectively.

Influence of Ca2+ doped on structural and optical properties of RPO4 (R = Ce3+, Nd3+ and Pr3+) compounds

This paper investigates the effect of doping by Ca2+ ions on the structural and optical properties of RPO4 (R=Ce3+, Nd3+ and Pr3+) compounds. A simple ceramic method in air at 900°C was used to prepare all compounds. The structural characterization of compounds was carried out by using X-ray powder diffraction (XRD) and IR spectroscopy. Optical properties were characterized by reflectance spectral data and by colorimeter. The results reveal a single monazite phase for x values up to 0.4. The lattice parameters of the synthesized samples decrease linearly with the reduction of ionic radius of the Ce3+. These rare earth phosphates based materials have a potential to be adopted for the eco-friendly colorants for paints and plastics.

Die topografische Beziehung des M. pronator quadratus zum Ansatz des M. brachioradialis - Implikationen für die Refixation nach palmarer Plattenosteosynthese distaler Radiusfrakturen

In open reduction and volar plate fixation of distal radius fractures, the pronator quadratus (PQ) muscle is usually detached at the radial edge of the distal radius. Repair of the muscle is reasonable for coverage of the plate and to maintain normal pronation of the forearm. However, repair of the muscle is not always satisfactory. In this study, the topographic relationship of both the PQ and the brachioradialis muscle (BR) insertions are investigated with regard to optimising the repair of the PQ in open reduction and volar plate fixation of distal radius fractures. Twelve forearm pairs fixed in formalin were examined. The muscular boundaries of the PQ and the insertion of the BR were dissected, photographs were taken and measured digitally. The average distance of the PQ insertion was 4.75 cm. Distally, a close topographic relationship exists between the insertions of both the PQ and BR. A fascial connection of both muscles was detected in all specimens. The average distance of the common insertion was 1.75 cm. After removal of the PQ fascia, 0.85 cm of common insertion remained. In 25 % a muscular connection between both the PQ and BR was detected after removal of the PQ fascia. Both the PQ and BR have a common connective tissue and partially a common muscular insertion. Detaching the PQ insertion with a part of the BR insertion in open reduction and volar plate fixation of distal radius fractures can presumably lead to a more stable repair of the PQ in contrast to a repair within the muscle.

Magnetic-field-induced delocalized to localized transformation in GaAs:N.

The use of a high magnetic field (57T) to study the formation and evolution of nitrogen (N) cluster and supercluster states in GaAs:N is demonstrated. A magnetic field is used to lift the conduction band edge and expose resonant N cluster states so that they can be directly experimentally investigated. The reduction of the exciton Bohr radius also results in the fragmentation of N supercluster states, enabling a magnetic field induced delocalized to localized transition. The application of very high magnetic fields thus presents a powerful way to probe percolation phenomena in semiconductors with bound and resonant isoelectronic cluster states.

Accuracy of Distal Radius Positioning Using an Anatomical Plate

Over the past decade, several anatomical plates have been introduced to improve the result of open reduction and internal fixation of the distal radius. Using 3-dimensional imaging techniques, the authors studied the accuracy and reproducibility of distal radius positioning using anatomical plates.Distal radius fractures and the correction of these fractures were simulated with plastic bone models of radii. The authors simulated a defect by removing an arbitrary wedge shape from the artificial radii. Two surgeons corrected these fractures by placing 2 anatomical plate types according to the plate manufacturers' instructions. The residual positioning errors of the distal segment in relation to the unaffected radii were determined using 3-dimensional imaging and were compared with naturally occurring bilateral radius differences in healthy individuals. In many cases, positioning does not agree with differences based on bilateral asymmetry in healthy patients.This study indicated the accuracy of anatomical plates. Positioning an anatomical plate may lead to considerable residual errors in individual patients. Volar distal radius plate shapes differ among plate manufacturers. Therefore, one plate may perform better than another in an individual.