Radiologic prognostic factors of curve progression in early degenerative lumbar scoliosis

OBJECTIVESeveral radiological parameters related to the aging spine have been reported as progression factors of early degenerative lumbar scoliosis (DLS). However, it has not been determined which factors are the most important. In this study the authors aimed to determine the risk factors associated with curve progression in early DLS.METHODSFifty-one patients with early DLS and Cobb angles of 5°–15° were investigated. In total, 7 men and 44 women (mean age 61.6 years) were observed for a mean period of 13.7 years. The subjects were divided into two groups according to Cobb angle progression (≥ 15° or < 15°) at the final follow-up, and radiological parameters were compared. The direction of scoliosis, apical vertebral level and rotational grade, lateral subluxation, disc space difference, osteophyte difference, upper and lower disc wedging angles, and relationship between the intercrest line and L5 vertebra were evaluated.RESULTSDuring the follow-up period, the mean curve progression increased from 8.8° ± 3.2° to 19.4° ± 8.9°. The Cobb angle had progressed by ≥ 15° in 17 patients (33.3%) at the final follow-up. In these patients the mean Cobb angle increased from 9.4° ± 3.4° to 28.8° ± 7.5°, and in the 34 remaining patients it increased from 8.5° ± 3.1° to 14.7° ± 4.8°. The baseline lateral subluxation, disc space difference, and upper and lower disc wedging angles significantly differed between the groups. In multivariate logistic regression analysis, only the upper and lower disc wedging angles were significantly correlated with curve progression (OR 1.55, p = 0.035, and OR 1.89, p = 0.004, respectively).CONCLUSIONSAsymmetrical degenerative change in the lower apical vertebral disc, which leads to upper and lower disc wedging angles, is the most substantial factor in predicting early DLS progression.

Bulge formation through disc instability

We use simulations to study the growth of a pseudobulge in an isolated thin exponential stellar disc embedded in a static spherical halo. We observe a transition from later to earlier morphological types and an increase in bar prominence for higher disc-to-halo mass ratios, for lower disc-to-halo size ratios, and for lower halo concentrations. We compute bulge-to-total stellar mass ratios B/T by fitting a two-component Sérsic-exponential surface-density distribution. The final B/T is strongly related to the disc’s fractional contribution fd to the total gravitational acceleration at the optical radius. The formula B/T = 0.5 fd1.8 fits the simulations to an accuracy of 30%, is consistent with observational measurements of B/T and fd as a function of luminosity, and reproduces the observed relation between B/T and stellar mass when incorporated into the GALICS 2.0 semi-analytic model of galaxy formation.

Effect of rGO@Fe3O4 on the tribological behavior of biodiesel soot-contaminated polyalphaolefin

The biodiesel soot interacts with engine oil and causes the wear of engine parts. In this study, we present the effects of rGO@Fe3O4 on the tribological behavior of the biodiesel soot-contaminated lubricating oil using a UMT-2 multifunction friction tester to ensure active control with respect to the role of biodiesel soot in engine oil. Three-dimensional laser scanning microscopy, field-emission scanning electron microscopy, and Raman spectroscopy were used to analyze the worn surfaces of the lower disc. rGO@Fe3O4 reduced the wear of the GCr15 steel specimens as an additive in the polyalphaolefin-6 base oil containing biodiesel soot. The tribological mechanism can be attributed to the formation of a protecting layer in the presence of rGO@Fe3O4 and the ability of the exfoliated Fe3O4 particles to repair the friction surfaces, enhancing the anti-wear property of polyalphaolefin-6 containing biodiesel soot.

Escargot is involved in labial and antennal imaginal disc development through two different developmental pathways

In insects, imaginal discs form the adult structures. Imaginal discs are formed by two epithelial layers, the lower disc proper columnar epithelium and the upper peripodial squamous epithelium (also known as peripodial membrane). During morphogenesis and metamorphosis there is a complex crosstalk between these two epithelia that defines the final size and form of the adult organs. In this work we found that in the antennal disc, the dosage of the transcriptional factor Escargot (Esg) regulates the extension of the peripodial epithelium. A reduction in Esg expands the peripodial domain at the expense of the antennal disc proper causing a distortion of the anteroposterior compartments resulting in malformations or duplications of antennae and maxillary palps. In the labial disc, a different morphogenetic pathway controls its development, and loss of esg produces a complete loss of the proboscis through a pathway that involves dpp.Summary statementThe gene escargot regulates proboscis, maxillary palps and antennae development in Drosophila melanogaster through two different developmental pathways: one involving cell adhesion protein DE-cadherin and another through the signaling molecule decapentaplegic.

The HD-OCT Study May Be Useful in Searching for Markers of Preclinical Stage of Diabetic Retinopathy in Patients with Type 1 Diabetes

The aim of the study was to analyze the thickness of individual retinal layers in patients with type 1 diabetes (T1D) in comparison to the control group and in relation to markers of diabetes metabolic control. The study group consisted of 111 patients with an average of 6-years of T1D duration. The control group included 36 gender- and age-matched individuals. In all patients optical coherence tomography (OCT) study was performed using HD-OCT Cirrus 5000 with evaluation of optic nerve head (ONH) parameters, thickness of retinal nerve fiber layer (RNFL) with its quadrants, macular full-thickness parameters, ganglion cells with inner plexus layer (GCIPL) and choroidal thickness (CT). Lower disc area value was observed in the study group as compared to controls (p = 0.0215). Negative correlations were found both between age at examination and rim area (R = −0.28, p = 0.0007) and between superior RNFL thickness and duration of diabetes (R = −0.20, p = 0.0336). Positive correlation between center thickness and SD for average glycemia (R = 0.30, p = 0.0071) was noted. Temporal CT correlated positively with age at examination (R = 0.21, p = 0.0127). The selected parameters the HD-OCT study may in the future serve as potential markers of preclinical phase of DR in patients with T1D.

Circumbinary discs with radiative cooling and embedded planets

Context. As of today, ten circumbinary planets orbiting solar type main sequence stars have been discovered. Nearly all orbit around the central binary very closely to the region of instability where it is difficult to form them in situ. Hence, it is assumed that they formed further out and then migrated to their observed position, which is determined by binary, disc and planet properties. Aims. We extend previous studies to a more realistic thermal disc structure and determine what parameter influence the final parking location of a planet around a binary star. Methods. We performed two-dimensional numerical simulations of viscous accretion discs around a central binary. These simulations include viscous heating and radiative cooling from the disc surfaces. We vary the binary eccentricity as well as disc viscosity and mass. Results. Concerning the disc evolution, we find that it can take well over 100 000 binary orbits until an equilibrium state is reached. As seen previously, we find that the central cavity opened by the binary becomes eccentric and precesses slowly in a prograde sense. Embedded planets migrate to the inner edge of the disc. In cases of lower disc viscosity they migrate further in maintaining a circular orbit, while for high viscosity they are parked further out on an eccentric orbit. Conclusions. Discs around binary stars are eccentric, and precess very slowly around the binary. The final location of an embedded planet is linked to its ability to open a gap in the disc. Gap-opening planets separate inner from outer disc, preventing eccentricity excitation in the latter and making it more circular. This allows embedded planets to migrate closer to the binary, in agreement with the observations. The necessary conditions for gap opening and the final planet position depend on the planet mass and disc viscosity.

Unsteady 360 Computational Fluid Dynamics Validation of a Turbine Stage Mainstream/Disc Cavity Interaction Using Lattice-Boltzmann Method

This paper is a continuation of a previous comparison dealing with URANS-based validation of the ASU-Honeywell turbine stage mainstream/disc-cavity interaction rig data. Here, the validation is with a CFD code named PowerFLOW which is based on the Lattice Boltzmann Method (or LBM). Transient LBM simulations were conducted across the previously published purge flows (Cw of 1540 to 6161), and at the higher mainstream flow condition of 2300 cfm (1.086m3/s). Sensitivity of convergence on results was investigated by increasing the number of revolutions, as well as by varying the passive scalar and temperature difference assumptions between mainstream and purge flow. Results indicate that at lower purge flow, LBM was able to significantly improve validation of sealing effectiveness measurements. For the intermediate purge flows, however, there is a departure from what the data shows. Finally, at the higher purge flow cases, LBM prediction improves at the outer radial location as compared to URANS. Moreover, on pressure validation, it has closed the gap in matching the measured steady pressures inside the lower disc cavity except at the highest purge flow. In the critical upper rim cavity, the gap between the two methods closes as purge flow increases. The outcome from this comparative tool validation study is that at the low critical purge flow case where ingestion is most critical as well as at the upper rim cavity location, sealing effectiveness predictions were significantly improved. The paper also discusses the current limitations of LBM.

Mixed convection flow of couple stress fluid between rotating discs with chemical reaction and double diffusion effects

The chemical reaction, Soret and Dufour effects on steady flow of a couple stress fluid between two rotating disks are studied. The lower disc is rotating with angular velocity

CFD Numerical Simulation of Biodiesel Synthesis in a Spinning Disc Reactor

In this paper a two-disc spinning disc reactor for intensified biodiesel synthesis is described and numerically simulated. The reactor consists of two flat discs, located coaxially and parallel to each other with a gap of 0.2 mm between the discs. The upper disc is located on a rotating shaft while the lower disc is stationary. The feed liquids, triglycerides (TG) and methanol are introduced coaxially along the centre line of rotating disc and stationary disc. Fluid hydrodynamics in the reactor for synthesis of biodiesel from TG and methanol in the presence of a sodium hydroxide catalyst are simulated, using convection-diffusion-reaction species transport model by the CFD software ANSYS©Fluent v. 13.0. The effect of the upper disc’s spinning speed is evaluated. The results show that the rotational speed increase causes an increase of TG conversion despite the fact that the residence time decreases. Compared to data obtained from adequate experiments, the model shows a satisfactory agreement.