Radial Orientation Research Articles

Anatomically correct assessment of the orientation of the cardiomyocytes using diffusion tensor imaging.

Diffusion tensor imaging has been used for assessing the orientation of cardiac myocytes for decades. Striking methodological differences exist between studies when quantifying these orientations. This limits the comparability between studies, and impedes collaboration and the drawing of appropriate physiological conclusions. We have sought to elucidate these differences, permitting us to propose a standardised "tool set" that might better establish consensus in future studies. We fixed hearts from seven 25kg pigs in formalin, and scanned them using diffusion tensor imaging. Using various angle definitions as found in literature, we assessed the orientations of cardiomyocytes, comparing them in terms of helical and intrusion angles, along with the orientation of their aggregations. The difference between assessment of the helical angle with and without relation to the epicardial curvature was 25.2° (SD: 7.9) at the base, 5.8° (1.9) at the equatorial level, and 28.0° (7.0) at the apex, ANOVA P=0.001. In comparable fashion, the intrusion angle differed by 25.9° (12.9), 7.6° (0.98) and 17.5° (4.7), P=0.01, and the angle of the aggregates (E3-angle) differed by 25.0° (13.5) at the base, 9.4° (1.7) at the equator, and 23.1° (6.2) apically, P=0.003. When assessing 14 definitions used in literature to calculate the orientation of aggregates, only 4 rendered identical results. The findings show that any attempt to use projection of eigenvectors introduces considerable bias. The epicardial curvature of the ventricular cone needs to be taken into account when seeking to provide accurate quantification of the orientation of the aggregated cardiomyocytes, especially in the apical and basal regions. This means that projection of eigenvectors should be avoided prior to quantifying myocyte orientation, especially when assessing radial orientation. Based on our results, we suggest appropriate methods for valid assessment of myocyte orientation using diffusion tensor imaging.

Trilayered tissue structure with leaflet-like orientations developed through in vivo tissue engineering

A tissue-engineered heart valve can be an alternative to current mechanical or bioprosthetic valves that face limitations, especially in pediatric patients. However, it remains challenging to produce a functional tissue-engineered heart valve with three leaflets mimicking the trilayered, oriented structure of a native valve leaflet. In our previous study, a flat, trilayered nanofibrous substrate mimicking the orientations of three layers in a native leaflet—circumferential, random and radial orientations in fibrosa, spongiosa and ventricularis layers, respectively, was developed through electrospinning. In this study, we sought to develop a trilayered tissue structure mimicking the orientations of a native valve leaflet through in vivo tissue engineering, a practical regenerative medicine technology that can be used to develop an autologous heart valve. Thus, the nanofibrous substrate was placed inside the closed trileaflet-shaped cavity of a mold and implanted subcutaneously in a rat model for in vivo tissue engineering. After two months, the explanted tissue construct had a trilayered structure mimicking the orientations of a native valve leaflet. The infiltrated cells and their deposited collagen fibrils were oriented along the nanofibers in each layer of the substrate. Besides collagen, presence of glycosaminoglycans and elastin in the construct was observed.

Soft Ring-Shaped Cellu-Robots with Simultaneous Locomotion in Batches.

Untethered mini-robots can move single cells or aggregates to build complex constructs in confined spaces and may enable various biomedical applications such as regenerative repair in medicine and biosensing in bioengineering. However, a significant challenge is the ability to control multiple microrobots simultaneously in the same space to operate toward a common goal in a distributed operation. A locomotion strategy that can simultaneously guide the formation and operation of multiple robots in response to a common acoustic stimulus is developed. The scaffold-free cellu-robots comprise only highly packed cells and eliminate the influence of supportive materials, making them less cumbersome during locomotion. The ring shape of the cellu-robot contributes to anisotropic cellular interactions which induce radial cellular orientation. Under a single stimulus, several cellu-robots form predetermined complex structures such as bracelet-like ring-chains which transform into a single new living entity through cell-cell interactions, migration or cellular extensions between cellu-robots.

Microanatomy and growth of the mesosaurs <i>Stereosternum tumidum</i> and <i>Brazilosaurus sanpauloensis</i> (Reptilia, Parareptilia)

Abstract. Histology and microanatomy of vertebrae, ribs, haemal arch, and humeri and femora of 10 individuals of Stereosternum and two dorsal ribs of 1 individual of Brazilosaurus were studied. All individuals had achieved a body length of 50 cm (equal to 65 % of the maximum known body length) or larger. All sampled bones are highly osteosclerotic due to the reduction of medullary cavities and the filling of medullary regions by endosteal bone. Calcified cartilage occurs – if at all – only locally in small clusters in the medullary regions of midshaft and in higher amounts only in non-midshaft sections of long bones and towards the medio-distal rib shaft, respectively. The primary bone tissue consists of highly organized parallel-fibred tissue and/or lamellar tissue, which is in most samples relatively lightly vascularized or even avascular. If present, vascular canals are mainly longitudinally oriented; some show a radial orientation. Simple vascular canals as well as primary osteons occur. Some of the latter are secondarily altered, i.e. widened. Remodelling of the periosteal cortex is only documented by few scattered erosion cavities and secondary osteons. The tissue is regularly stratified by lines of arrested growth (LAGs), which usually appear as double or multiple rest lines, indicating strong dependence on exogenous and endogenous factors. Because of the inhibition of periosteal remodelling the growth record is complete and no inner cycles are lost. Individuals of Stereosternum show a poor correlation of body size and number of growth marks, which might be the result of developmental plasticity. Brazilosaurus shows a highly organized, avascular lamellar tissue and a high number of regularly deposited rest lines throughout the cortex of the ribs. The medullary region in the ribs of Brazilosaurus is distinctly larger when compared to ribs of Stereosternum. However, strong osteosclerosis is obvious in both taxa, pointing to a high degree of aquatic adaption. Ribs of Stereosternum, Brazilosaurus, and Mesosaurus are clearly distinguishable from each other by the distribution of the periosteal and endosteal territory. Furthermore, Brazilosaurus differs in its growth pattern (i.e. spacing of rest lines) when compared to Stereosternum and Mesosaurus.

Experimental study of the contact forces and deformations of mortise-and-tenon joints considering the fits and grain orientations of the tenon

A method to measure the contact forces and deformations of mortise and tenon joints based on previous theoretical studies was proposed. The influence of the tenon fits and grain orientations on the contact forces and deformations of the mortises and tenons were studied using this method. The testing method and equations were all introduced in detail. The results showed that the contact force between the mortise and tenon with the tenon in the radial grain orientation was larger than that for the tenon in the tangential grain orientation with the same tenon fit. An exponential relationship between the contact force and tenon fit was found. Also, the deformation of the mortise was 3.6 times smaller than the tenon with a tangential grain orientation and 2.2 times smaller than the tenon with a radial grain orientation.

Organization of the subumbrellar musculature in the ephyra, juvenile, and adult stages of Aurelia aurita Medusae

AbstractWe used fluorescently labeled phalloidin to examine the subumbrellar musculature of the scyphozoan jellyfish Aurelia aurita in a developmental series from ephyra to adult medusa. In the ephyra, the swim musculature includes a disc‐like sheet of circular muscle, in addition to two radial bands of muscle in each of the eight ephyral arms. The radial muscle bands join with the circular muscle, and both circular and radial muscle act together during each swim contraction. As the ephyra grows into a juvenile medusa, arms tissue is resorbed as the bell tissue grows outward, so eventually, the ephyral arms disappear. During this process, the circular muscle disc also grows outward and the radial muscle bands of the arms also disappear. At this time, a marginal gap appears at the bell margin, which is devoid of circular muscle cells, but has a loose arrangement of radial muscle fibers. This marginal gap is preserved as the medusa grows, and contributes to the floppy nature of the bell margin. Radial distortions in the circular muscle layer involve muscle fibers that run in random directions, with a primarily radial orientation. These are believed to be remnants of the radial muscle of the ephyral arms, and the distortions decrease in number and extent as the medusa grows. Since the mechanics of swimming changes from drag‐based paddling in the ephyra to marginal rowing in the adult medusa, the development of the marginal gap and the presence of radial distortions should be considered in terms of this mechanical transition.

Spin-resolved atomic orbital model refinement for combined charge and spin density analysis: application to the perovskite

A new crystallographic method is proposed in order to refine a spin-resolved atomic orbital model against X-ray and polarized neutron diffraction data. This atomic orbital model is applied to the YTiO3 perovskite crystal, where orbital ordering has previously been observed by several techniques: X-ray diffraction, polarized neutron diffraction and nuclear magnetic resonance. This method gives the radial extension, orientation and population of outer atomic orbitals for each atom. The interaction term between Ti3+, Y3+ cations and O2− ligands has been estimated. The refinement statistics obtained by means of the orbital method are compared with those obtained by the multipole model previously published.

Finite Element Simulation to Determine Tree Safety Factor Using Geoelectrical Mapping as an Input

The distribution of stress and strain of the root in the ground can be used to determine the stability of a tree. The distribution itself is affected by the root architectural factor, the shear and tensile strength of ground and tree, and the geometry. The root architectures are mapped using geoelectrical method. In this method we use dipole-dipole configuration. Geophysical data acquisition was carried out with 6 lines of 3 m length, 25 cm electrode spacing and radial orientation around the target tree to map the distribution of the secondary root, an also a line of 15 m length, 1 m spacing and east-west orientation to map the maximum depth of the primary root. This research is conducted in Lapangan Sipil of Institut Teknologi Bandung. Geophysical data inversion is done to get the root architecture. The geoelectric data processing is done using RES2DINV software. We obtain the shear and tensile strength of the ground from literature study. The inversion result and literature data are used as input to do finite element situation to get the distribution of stress and strain of the tree and the ground. Finally, the result of the simulation can be used to determine the safety factor of the tree in certain weather.

Model predictive control of induction motor based on amplitude–phase motion equation

Tedious adjustment of the weighting factor restricts the wide application of conventional model predictive torque control (MPTC) for induction motors (IMs) in practice. To solve this problem, this study introduces a new variable R (reactive torque) to control the flux of IM, which is the dual of torque T , with radial orientation and in relation to reactive power. Then, a novel MPTC strategy based on variable R and torque T is proposed and named RT-MPC. Compared with conventional MPTC, RT-MPC uses a pair of variables with the same dimensions and time scales instead of the torque and flux amplitude in MPTC. This approach eliminates the weighting factor of the cost function, unifies the time scales of control variables, and avoids prediction of rotor flux at the ( k + 2) instant. Simulation and experimental results show that RT-MPC can avoid the weighting factor, reduce switching frequency, and reduce control complexity. RT-MPC can also maintain excellent dynamic and steady-state performance similar to conventional MPTC. Hence, the proposed method is expected to be more practical.

Functional disuse initiates medullary endosteal micro-architectural impairment in cortical bone characterized by nanoindentation.

In this study, we evaluated the effect of functional disuse-induced bone remodeling on its mechanical properties, individually at periosteum and medullary endosteum regions of the cortical bone. Left middle tibiae were obtained from 5-month-old female Sprague-Dawley rats for the baseline control as well as hindlimb suspended (disuse) groups. Micro-nano-mechanical elastic moduli (at lateral region) was evaluated along axial (Z), circumferential (C) and radial (R) orientations using nanoindentation. Results indicated an anisotropic microstructure with axial orientation having the highest and radial orientation with the lowest moduli at periosteum and medullary endosteum for both baseline control as well as disuse groups. Between the groups: at periosteum, an insignificant difference was evaluated for each of the orientations (p > 0.05) and at endosteum, a significant decrease of elastic moduli in the radial (p < 0.0001), circumferential (p < 0.001) and statistically insignificant difference in axial (p > 0.05) orientation. For the moduli ratios between groups: at periosteum, only significant difference in the Z/R (p < 0.05) anisotropy ratio, whereas at endosteum, a statistically significant difference in Z/C (p < 0.001), andZ/R (p < 0.001), as well as C/R (p < 0.05) anisotropy ratios, was evaluated. The results suggested initial bone remodeling impaired bone micro-architecture predominantly at the medullary endosteum with possible alterations in the geometric orientations of collagen and mineral phases inside the bone. The findings could be significant for studying the mechanotransduction pathways involved in maintaining the bone micro-architecture and possibly have high clinical significance for drug use against impairment from functional disuse.

Width and length dependent SERS performance of core-shell Au@Ag nanorod self-assembled monolayers

An efficient and facile strategy for producing core-shell Au@Ag nanorods (NRs) with controllable width and length as excellent surface enhanced Raman scattering (SERS) substrate was proposed. Au nanodipyramids (NDPs) of three various widths were prepared by overgrowth along the radial orientation, and together with Au NDPs as seed, silver was deposited in the axial orientation to successfully obtain core-shell Au@Ag NRs with diverse length (73 nm–157 nm) and width (25 nm–43 nm). The morphology, optical properties and SERS performance of the as-synthesized Au@Ag NRs were investigated systematically. The broadly tunable UV-Vis absorption range for Au@Ag NRs as far as the near-infrared (NR) region was able to be obtained. Furthermore, the SERS property of Au@Ag NRs two-dimensional monolayer was explored by using crystal violet (CV) as Raman probe. The optimal SERS enhancement effect with enhancement factor (EF) as high as 6.13✕105 could be achieved for Au@Ag NRs with wider width and longer length, which was confirmed by the simulation results of electromagnetic (EM) field distribution by FDTD method. Our novel approach provides some facinating insights into adjusting the width of Au@Ag NRs, which also significantly influences the SERS behaviors of the Au@Ag NRs. It allows to fabricating SERS substrate with superior SERS performance compared to previously reported Au@Ag NRs only with tunable length via direct overgrowth. Besides, this as-compounded Au@Ag NRs are expected to have promising application and significant value in other fields.

Numerical modeling of high efficiency multistage plasma thrusters for space applications

The high efficiency multistage plasma-thruster (HEMP-T) represents an ion thruster technology that was developed by Thales Deutschland GmbH beginning in the early 2000s. It features a dielectric-coated discharge channel with an anode at the channel bottom. A magnetic field is applied by periodic permanent magnets (PPMs) that is mostly axially oriented in most channel regions, with radial orientation only at spatially confined magnetic cusps resulting in low particle fluxes towards the dielectric wall. The typical length scales in the description of the HEMP-T plasma range from microscopic over mesoscopic to macroscopic. Microscopic effects are introduced, e.g., by atomic interactions and surface interactions. Mesoscopic scales appear by the gyro radius of particles in the magnetic field and the formation of a transition zone between plasmas and walls on the length scale of some Debye lengths, respectively. Large-scale macroscopic length scales are introduced, e.g., by the plume expansion and interaction with test vessel walls. For a correct description of both thruster and plume plasma, one has to solve a kinetic problem for the whole region of interest, including all significant physical processes. This review offers an overview of modeling strategies and their results for the HEMP thruster. The axisymmetric 2D3v Particle-in-Cell (PIC) simulation method is used to identify the basic physics of the acceleration channel and the near-field plume region. Direct comparison with the observed plasma radiation and angular ion energy distributions, both for stationary and dynamic modes, is also presented. While good qualitative agreement with experimental data is achieved, even better agreement with experiments is necessary to predict thruster performance via numerical models in the future. The limited size of the simulation domain restricts the study of the coupled thruster-plume dynamics, which is an important aspect for the interaction of ion thruster and carrier spacecraft. Improvements in computer technology, the use of hierarchical models and the multigrid method discussed in this review can help overcome these limits and improve the quality of predictive thruster modeling.

A Morphodynamic Modeling Study on the Formation of the Large‐Scale Radial Sand Ridges in the Southern Yellow Sea

AbstractThe radial sand ridges (denoted as “RSRs” hereafter) in the Southern Yellow Sea, China, are morphologically striking because of the remarkable size and radial planar orientation, standing out as a unique coastal geomorphology among the worldwide sand ridge systems. The formation of this giant fan‐shaped geomorphic feature requires delicate conditions and awaits in‐depth investigation. Using an idealized morphodynamic model, this study unravels the governing factors for the formation of the unique large‐scale RSRs, in comparison with other types of sand ridge systems over the world. The effects of the M2 tidal constituent, the Coriolis forcing, the bed resistance, and the initial water depths on the morphodynamic behavior of the RSRs are explored. Numerical results indicate that the tidal regime, characterized by rotational and progressive current action associated with the tidal bulge, is dependent on the eastern coastline of China as well as latitudinal effects. Through the comparison between the simulated and the measured morphology, this tidal regime is demonstrated to be the key driver in forming and maintaining the present‐day RSRs. The runs with different parameters further suggest that the asymmetric pattern of the RSRs, which shows larger northern sand ridges than the southern ones, results from both the asymmetric distribution of current activity caused by the tidal bulge and unequal sediment supply. Overall, this study highlights the delicate condition, predominantly represented by the particular currents set up by the tidal wave system and the sediment supply, required to shape the striking large‐scale RSRs in the Southern Yellow Sea.

Experimental and Monte-Carlo characterization of the novel compact ionization chamber PTW 31023 for reference and relative dosimetry in high energy photon beams

IntroductionThe aim of the present work is to perform dosimetric characterization of a novel vented PinPoint ionization chamber (PTW 31023, PTW-Freiburg, Germany). This chamber replaces the previous model (PTW 31014), where the diameter of the central electrode has been increased from 0.3 to 0.6mm and the guard ring has been redesigned. Correction factors for reference and non-reference measurement conditions were examined. Materials and methodsMeasurements and calculations of the correction factors were performed according to the DIN 6800-2. The shifts of the effective point of measurement (EPOM) from the chamber's reference point were determined by comparison of the measured PDD with the reference curve obtained with a Roos chamber. Its lateral dose response functions, which act according to a mathematical convolution model as the convolution kernel transforming the dose profile D(x) to the measured signal M(x), have been approximated by Gaussian functions with standard deviation σ. Additionally, the saturation correction factors kS have been determined using different dose-per-pulse (DPP) values. The polarity effect correction factors kP were measured for field sizes from 5cm×5cm to 40cm×40cm. The influence of the diameter of the central electrode and the new guard ring on the beam quality correction factors kQ was studied by Monte-Carlo simulations. The non-reference condition correction factors kNR have been computed for 6MV photo beam by varying the field size and measurement depth. Comparisons on these aspects have been made to the previous model. ResultsThe shifts of the EPOM from the reference point, Δz, are found to be −0.55 (6MV) and −0.56 (10MV) in the radial orientation and −0.97mm (6MV) and −0.91mm (10MV) in the axial orientation. All values of Δz have an uncertainty of 0.1mm. The σ values are 0.80mm (axial), 0.75mm (radial lateral) and 1.76mm (radial longitudinal) for 6MV photon beam and are 0.85mm (axial), 0.75mm (radial lateral) and 1.82mm (radial longitudinal) for 15MV photon beam. All σ values have an uncertainty of 0.05mm. The correction factor kS was found to be 1.0034±0.0009 for the PTW 31014 chamber and 1.0024±0.0007 for the PTW 31023 chamber at the highest DPP (0.827mGy) investigated in this study. Under reference conditions, the polarity effect correction factor kP of the PTW 31014 chamber is 1.0094 and 1.0116 for 6 and 10MV respectively, while the kP of the PTW 31023 chamber is 1.0005 and 1.0013 for 6 and 10MV respectively, all values have an uncertainty of 0.002. The kP of the new chamber also exhibits a weaker field size dependence. The kQ values of the PTW 31023 chamber are closer to unity than those of the PTW 31014 chamber due to the thicker central electrode and the new guard ring design. The kNR values of the PTW 31023 chamber for 6MV photon beam deviate by not more than 1% from unity for the conditions investigated. DiscussionsCorrection factors associated with the new chamber required to perform reference and relative dose measurements have been determined according to the DIN-protocol. The correction factor kS of the new chamber is 0.1% smaller than that of the PTW 31014 at the highest DPP investigated. Under reference conditions, the correction factor kP of the PTW 31023 chamber is approximately 1% smaller than that of the PTW 31014 chamber for both energies used. The dosimetric characteristics of the new chamber investigated in this work have been demonstrated to fulfil the requirements of the TG-51 addendum for reference-class dosimeters at reference conditions.

Parametric effects on the evaluation of threshold chromaticity differences using red printed samples.

Results from different authors showed deviations of radial orientation in the a*-b* plane (tilt) for the major axes of chromaticity-discrimination ellipses centered around the International Commission on Illumination (CIE) red color center [Color Res. Appl.3, 149 (1978)CREADU0361-2317], which are not considered by most of the current advanced color-difference formulas (e.g., CIEDE2000). We performed a visual experiment using red printed samples in order to test the influence of the separation between samples (gap) on the mentioned tilt. Our results confirm a counterclockwise tilt of fitted a*-b* ellipses with a magnitude of approximately 36° for samples with no separation, which is similar to that detected by other authors, and a reduction of the mentioned tilt owing to the separation of the samples. We detected a tilt of approximately 22° for samples with a black gap of 0.5mm and a tilt of approximately 25° for samples with a white gap of 3mm. Notably, the uncertainty of previous values given by the corresponding credibility intervals of 95% posterior probability is approximately ±8° of the mean values. Finally, we study the performance of the most widely used color-difference formulas in the graphic arts sector using our current experimental results, and conclude that the performance of the CAM02-SCD and CAM02-UCS color-difference formulas is significantly better than that of the CIEDE2000 formula.

Low frequency acoustical scattering from dynamic schools of swim bladder fish

A time-domain computational model is used to describe the dynamic evolutions of fish schools. The individual and ensemble fish behaviors are governed by three radial parameters, representing attraction, orientation, and repulsion zones between fishes. Different combinations of these radii cause the schools to evolve into various discoid, swarming, parallelized, or toroidal geometric forms. A previously developed model [J. Acoust. Soc. Am. 99, 196–208 (1996)] is applied to study the variations in ensemble scattering from these school types for ensonification frequencies in the swim bladder resonance region, as a function of frequency and time, and predicts distinct characteristic features for the different school geometries. In particular, this work focuses on scattering from disk-shaped schools, by examining the computed resonance response for different school dimensions, packing density, and orientation, in order to identify specific features that are determinative for this type of arrangement. The ultimate goal of this work is to achieve a better understanding of the physical basis for variations in fish school scattering levels and to obtain a detailed statistical description of these objects. [Work supported by ONRG.]

An Induction System for Clustered Stomata by Sugar Solution Immersion Treatment in Arabidopsis thaliana Seedlings.

Stomatal movement mediates plant gas exchange, which is essential for photosynthesis and transpiration. Stomatal opening and closing are accomplished by a significant increase and decrease in guard cell volume, respectively. Because shuttle transport of ions and water occurs between guard cells and larger neighboring epidermal cells during stomatal movement, the spaced distribution of plant stomata is considered an optimal distribution for stomatal movement. Experimental systems for perturbing the spaced pattern of stomata are useful to examine the spacing pattern's significance. Several key genes associated with the spaced stomatal distribution have been identified, and clustered stomata can be experimentally induced by altering these genes. Alternatively, clustered stomata can be also induced by exogenous treatments without genetic modification. In this article, we describe a simple induction system for clustered stomata in Arabidopsis thaliana seedlings by immersion treatment with a sucrose-containing medium solution. Our method is easy and directly applicable to transgenic or mutant lines. Larger chloroplasts are presented as a cell biological hallmark of sucrose-induced clustered guard cells. In addition, a representative confocal microscopic image of cortical microtubules is shown as an example of intracellular observation of clustered guard cells. The radial orientation of cortical microtubules is maintained in clustered guard cells as in spaced guard cells in control conditions.

Endoscopic identification of endoluminal esophageal landmarks for radial and longitudinal orientation and lesion location

AIMTo characterize esophageal endoluminal landmarks to permit radial and longitudinal esophageal orientation and accurate lesion location.METHODSDistance from the incisors and radial orientation were estimated for the main left bronchus and the left atrium landmarks in 207 consecutive patients using white light examination. A sub-study was also performed using white light followed by endoscopic ultrasound (EUS) in 25 consecutive patients to confirm the findings. The scope orientation throughout the exam was maintained at the natural axis, where the left esophageal quadrant corresponds to the area between 6 and 9 o’clock. When an anatomical landmark was identified, it was recorded with a photograph and its quadrant orientation and distance from the incisors were determined. The reference points to obtain the distances and radial orientation were as follows: the midpoint of the left main bronchus and the most intense pulsatile zone of the left atrium. With the video processor system set to moderate insufflation, measurements were obtained at the end of the patients’ air expiration.RESULTSThe left main bronchus and left atrium esophageal landmarks were identified using white light in 99% and 100% of subjects at a mean distance of 25.8 cm (SD 2.3), and 31.4 cm (SD 2.4) from the incisors, respectively. The left main bronchus landmark was found to be a tubular, concave, non-pulsatile, esophageal external compression, occupying approximately 1/4 of the circumference. The left atrium landmark was identified as a round, convex, pulsatile, esophageal external compression, occupying approximately 1/4 of the circumference. Both landmarks were identified using white light on the anterior esophageal quadrant. In the sub-study, the left main bronchus was identified in 24 (92%) patients at 25.4 cm (SD 2.1) and 26.7 cm (SD 1.9) from the incisors, by white light and EUS, respectively. The left atrium was recognized in all patients at 30.5 cm (SD 1.9), and 31.6 cm (SD 2.3) from the incisors, by both white light and EUS, respectively. EUS confirmed that the landmarks corresponded to these two structures, respectively, and that they were located on the anterior esophageal wall. The Bland-Altman plot demonstrated high agreement between the white light and EUS measurements.CONCLUSIONThis study provides an endoscopic characterization of esophageal landmarks corresponding to the left main bronchus and left atrium, to permit radial and longitudinal orientation and accurate lesion location.

Iris varix: 10-year experience with 28 eyes

Purpose:The purpose of this study is to describe the clinical characteristics, multimodality imaging findings, and clinical course of iris varices.Methods:Retrospective, noncomparative, observational case series of 28 eyes of 26 patients with iris varices, diagnosed between 2007 and 2017, has been used.Results:The mean (±SD) age was 58.3 ± 12.5 years (median 57.5, range 37–81). Patients were 57.7% male and 27% hypertensive. Varices were bilateral in two patients. The mean and median visual acuities were both 20/20 (range 20/16–20/40). Intraocular pressures were 16 mmHg (10–23 mmHg). Secondary glaucoma did not occur. The inferotemporal iris quadrant was affected in 75%. A single varix was seen in 64% and 36% appeared multiple. Varix orientation was radial in 57% and circumferential in 21%. Combined radial and circumferential varix orientation was noted in 18%. One had independent radial and circumferential varices in separate quadrants. A single episcleral sentinel blood vessel directed to the varix was present in 36%. Ultrasound biomicroscopy (UBM) showed a slightly increased mean iris thickness of 0.8 mm and multiple echolucent iris stromal vascular channels. Iris angiography showed no leakage of dye. Managed by observation over a mean follow-up of 37.7 months (range, 3–129), 96.4% eyes were stable and one (3.6%) regressed. No corectopia, ectropion uveae, hyphema, or metachronous anterior segment benign or malignant tumors occurred.Conclusion:Iris varix is primarily located in the inferotemporal quadrant and not associated with dysmorphic pupillary findings, progression, secondary glaucoma, or malignancy. Iris varices were benign vasculopathies with no associated ocular or vision-related morbidity.

Growth of regular micro-pillar arrays on steel by polarization-controlled laser interference patterning

Three-beam laser interference patterning, with the ability to control the polarization of each beam, is used to produce crater and pillar like periodic structures on steel surfaces. The experiments are performed using parallel and radial polarization vector orientations of the interfering beams. In case of parallel vector orientation, common intensity profiles consisting of intensity peaks distributed in triangle lattice geometry are formed. By changing the polarization to the radial set, the intensity distribution of the interference pattern could be inverted while the geometry also has a triangle lattice shape. The equations describing both intensity profiles are derived from the basic interference equation and the modeled interference intensity profiles are compared with measured intensity profiles. Two different types of structures containing periodically distributed craters and pillars are produced using these polarization sets. Using a detailed analysis of the scanning electron microscope images and confocal data, the mechanisms responsible of the formation of the pillar- and crater-like geometries are introduced.