Faint Ring Research Articles

From traffic jams to roadblocks: The outer regions of TW Hya with ALMA Band 8

Current ALMA surveys often underestimate protoplanetary disk sizes as many disks have extended low surface-brightness regions that fall below ALMA's detection limits. To effectively capture faint millimeter continuum emission in these outer regions, increased sensitivity is required. In order to gain insights on the connection between disk structure and planet formation, we aim to uncover continuum emission in the outer regions of the disk around TW Hya. Additionally, we aim to investigate the evolution of this disk by studying its dust properties. We present Atacama Large Millimeter Array (ALMA) observations of TW Hya at 0.65 mm with sim 0.5 arcsecond angular resolution, together with high angular resolution archival observations at 0.87 mm, 1.3 mm, 2.1 mm and 3.1 mm. We constrain the outer disk emission with both image-plane retrieval, and visibility-plane modeling with non-parametric and parametric fitting tools. Our results confirm emission in the outer disk regions of TW Hya (60 au leq R leq 110 au) at 0.65 mm, 0.87 mm and 1.3 mm. With image-plane retrieval we resolve the new continuum gap and ring, namely D79 and B86, at 0.87 mm and 1.3 mm. With visibility-plane modeling we also detect this substructure at 0.65 mm in the form of a quasi-constant emission at the 1sigma level Furthermore, it has a high spectral index of 3.7, which may indicate dust grain sizes ll 1 mm. It may be a dust trap or a traffic jam, that has a flux density of sim 60 mJy and a mass (1.59 $M_ that accounts for up to 2<!PCT!> of the dust disk at 0.65 mm. We confirm the existence of a faint ring in the outer regions of TW Hya at multiple millimeter wavelengths. With visibility-plane modeling, we are able to set constrains that are 3 times better than the resolution of our Band 8 observations.

Beyond the rings: Polar ring galaxy NGC 4262 and its globular cluster system

ABSTRACT In the context of the hierarchical model of galaxy evolution, polar ring galaxies (PRGs) are considered the intermediate phase between ongoing mergers and quiescent galaxies. This study explores the globular cluster system (GCS) and its properties in the nearest PRG, NGC4262, serving as a pilot investigation to study GCS in nearby PRGs. We utilize wide and deep-field observations of the CFHT as part of the NGVS to investigate the GCS of NGC4262. We presented the first optical image of NGC4262 with an optically faint ring component. The photometric analysis of the GCS displays a distinct colour bimodality. We estimate the total number of GCs for NGC4262 to be 266 $\pm$ 16 GCs with a specific frequency of 4.2 $\pm$ 0.8 and a specific mass of 0.23 $\pm$ 0.01, which is relatively high compared to other galaxies of similar mass and environmental conditions. The spatial and azimuthal distributions of subpopulations reveal strong evidence of previous interactions within the host galaxy. The colour distribution of GCS in NGC4262 shows a gradient of –0.05 $\pm$ 0.01 within 5.5$^\prime$, supporting the notion of past interactions and evolutionary transitions. PRG NGC4262 conforms to the overall trend of the GCS mass with respect to the halo mass. Furthermore, our investigation of the global scaling relations between GCS and host galaxy parameters provides further support for the hypothesis that PRGs are an intermediate phase connecting ongoing mergers and quiescent galaxies.

Evaluation of linear dermatoses by reflectance confocal microscopy in children.

Lichen striatus (LS), linear psoriasis (LPs), linear cutaneous lupus erythematosus (LCLE) and linear lichen planus (LLP) often have similar clinical manifestations, which makes clinical diagnosis with the naked eye difficult; therefore, they are easily misdiagnosed. The purpose of this study was to determine whether reflectance confocal microscopy (RCM) is helpful in differentiating between these four linear dermatoses in children. This retrospective study included 14 patients with LS, nine with LPs, eight with LCLE and 12 with LLP. All patients were analysed using RCM, and biopsies were collected from lesions previously imaged by RCM. For LS, the dermal papillary rings were partially absent, but when present, manifested with small, homogeneously round, bright cells and occasionally highly refractive plump cellular structures, aggregated in clusters. LPs exhibited dark cyst-like structures with small, bright, round cells aggregated at the epidermal level; at the dermal-epidermal junction, homogeneously distributed, enlarged, faint dermal papillary rings and numerous enlarged low-refractive canalicular structures were observed in the superficial dermis. LCLE and LLP exhibited similar manifestations, including epidermal disarray, almost total absence of dermal papillary rings, and various sized refractive structures densely distributed in the dermis. The key distinguishing features of LCLE were the different sized structures mainly clustered around hair follicles, while LLP demonstrated dense structures with a scattered distribution. RCM may be used to distinguish between the key features of LS, LPs, LCLE and LLP in children.

First Report of Colletotrichum siamense Causing Anthracnose on Dioscorea alata in China.

Dioscorea alata is an annual or perennial dicotyledonous plant which is a vegetatively propagated tuberous food crop (Mondo et al. 2021). In 2021, symptoms of leaf anthracnose occurred on D. alata plants at a plantation in Changsha, the Hunan Province of China (28°18' N; 113°08'E). Symptoms initially showed as small, brown water-soaked spots on the leaf surface or margins, and enlarged to irregular, dark brown or black, necrotic lesions, with a lighter center and darker edge. At latter, lesions extended to most of the leaf surface causing leaf scorch or wilting. Almost 40% of the plants surveyed were infected. Symptomatic leaf samples were collected, and small pieces were taken at their disease-healthy junction, sterilized with 70% ethanol for 10 s, 0.1% HgCl2 for 40 s, rinsed three times with sterile distilled water, and then placed on potato dextrose agar (PDA) for incubation at 26 °C for 5 days in the dark. Fungal colonies with similar morphology were observed and, in total, 10 isolates were obtained from 10 plants. On PDA, colonies were initially white with fluffy hyphae, and later became light to dark gray, showing faint concentric rings. Conidia were hyaline, aseptate, cylindrical, and rounded at both ends, measuring 11.36 to 17.67 × 3.45 to 5.9 μm (n = 50). Appressoria were dark brown, ovate, globose, measuring 6.37 to 7.55 × 10.11 to 12.3 µm. These morphological characteristics were typical of Colletotrichum gloeosporioides species complex (Weir et al. 2012). For molecular identification, the internal transcribed spacer (ITS) region of rDNA, and partial sequences of actin (ACT), chitin synthase (CHS-1), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes of a representative isolate Cs-8-5-1 were amplified and sequenced using the primer pairs ITS1/ITS4, ACT-512F/ACT-783R, CHS-79F/CHS-354R, and GDF/GDR as described previously (Weir et al. 2012). These sequences were deposited in GenBank (accession nos. OM439575 for ITS, OM459820 for ACT, OM459821 for CHS-1, and OM459822 for GAPDH). BLASTn analysis showed 99.59 to 100 % identity to the corresponding sequences of C. siamense strains. A Maximum likelihood phylogenetic tree based on the concatenated ITS, ACT, CHS-1 and GAPDH sequences was generated by MEGA 6. It revealed that the Cs-8-5-1 was clustered with the C. siamense strain CBS 132456 with 98% bootstrap support. For pathogenicity test, conidia suspension (105 spores/ml) was prepared by harvesting conidia from 7-day-old cultures growing on PDA, and 10 uL was dropped onto leaves of potted D. alata plants (8 droplets per leaf). Leaves treated with sterile water were served as controls. All the inoculated plants were placed in humid chambers (with 90% humidity) at 26°C with a photoperiod of 12 h. The pathogenicity tests were performed twice, with each had three replicated plants. Seven days after inoculation, the inoculated leaves showed symptoms of brown necrosis resembling that observed in fields, however, the control leaves remained symptomless. The fungus was specifically re-isolated and identified by morphological and molecular methods, thus fulfilling Koch's postulates. To our knowledge, this is the first report of C. siamense causing anthracnose on D. alata in China. Since this disease might seriously affect the photosynthesis of the plants, which can influence the yield, prevention and management strategies should be adopted to control this new disease. Identification of this pathogen will provide a foundation for the diagnosis and control of this disease.

Fundus autofluorescence, optical coherence tomography and electroretinography abnormalities in a patient with digoxin retinopathy that resemble those in KCNV2-associated retinopathy.

Digoxin related retinal toxicity causes blurred vision, photophobia, central scotoma, color vision abnormality, and electroretinography (ERG) abnormalities. Here, we report a case with transient abnormalities in vison, in which fundus autofluorescence (FAF), optical coherence tomography (OCT), and ERG findings resembled those in KCNV2 (potassium voltage-gated channel modifier subfamily V member 2)-associated retinopathy. An 89-year-old woman presented with complaints of acute blurred vision, nyctalopia, photophobia, and color vision abnormality. She received digoxin for tachycardia induced by atrial fibrillation for a month. The fundi showed a faint white ring at the fovea, which showed hyperfluorescence in FAF. OCT showed a thickened EZ in the macula. A dark-adapted (DA)-30 ERG showed a reduced and "squaring (trough-flattened)" a-wave, and a delayed, supernormal b-wave, resulting in a high b/a-wave amplitude ratio. The digoxin dose was reduced following an elevation in serum levels. Five weeks later, her visual acuities improved, and abnormal hyperfluorescence on FAF disappeared. After 6months, no visual symptoms were reported. The ellipsoid-zone thickening in OCT improved; however, the b/a-wave amplitude ratio on DA-30 ERG remained high. The b-wave in LA-long-flash ERG was initially reduced, which improved after correction of serum level of digoxin. The patient's clinical findings resembled those of patients with KCNV2-associated retinopathy or temporal hyperkalemia. These disorders appear to have a common pathogenesis, which may be related to abnormal extracellular potassium levels in the retina. The on-bipolar cells seemed to be more affected than the off-bipolar cells in digoxin related retinal toxicity.

Validation of otolith daily ring deposition and hatch date estimations in larval and juvenile Japanese flounder Paralichthys olivaceus

The early life history traits of Japanese flounder Paralichthys olivaceus, a commercially important species, have been well studied; however, daily ring formation in otoliths (lapilli and sagittae) of this species has not been investigated in detail. We examined the daily periodicity of ring deposition in otoliths using hatchery-reared Japanese flounder larvae and juveniles. In both lapilli and sagittae, a check corresponding to the radius at hatching (ca. 6 µm) was discernible throughout the pelagic larval and settled juvenile periods. The otolith rings were faint in the preflexion larval period and distinct in the flexion larval and later periods. Regression analyses for the number of rings by age in days showed that ring deposition occurred daily in lapilli but not in sagittae. Double marking of juveniles with alizarin complexone confirmed the daily ring periodicity in lapilli. However, the first faint ring was observed in the innermost areas in lapilli at 3–16 d post-hatching, and the faint rings were often unrecognisable, even under a scanning electron microscope, which interfered with daily age estimation. To estimate the number of days corresponding to the obscure zone with unrecognisable rings in lapilli, we developed the estimation method using logarithmic functions derived from the relationship between the radius (restricted to <20 µm) of lapilli and the ring counts for individual data. The error for the estimated days was − 0.05 ± 2.13 (n = 26, mean ± SD), indicating that this method is useful for hatch date estimation. Thus, the present study provides a novel method for analysis of otolith daily increments with unclear narrow rings in the innermost part of the otoliths.

Teaching NeuroImages: Frontal lobe Streptococcus abscess

A 21-year-old woman presented with a generalized tonic-clonic seizure, followed by 2 days of worsening headache. She was afebrile with normal serology and normal funduscopic and neurologic examination. CT head showed a frontal mass with surrounding edema concerning for primary brain tumor, demyelination, metastases, or infection. MRI brain revealed a ring-enhancing lesion characteristic for brain abscess.1 CSF cultures grew Streptococcus intermedius and the source was presumed to be from dental cleaning 2 weeks prior.2 Review of original scans revealed a faint hyperdense ring (figure, B), highlighting this pertinent radiologic finding and importance of considering abscess in patients with frontal lobe lesion, even in the absence of infectious findings.

ALMA Detection of Dust Trapping around Lagrangian Points in the LkCa 15 Disk

We present deep high-resolution (∼50 mas, 8 au) Atacama Large Millimeter/submillimeter Array (ALMA) 0.88 and 1.3 mm continuum observations of the LkCa 15 disk. The emission morphology shows an inner cavity and three dust rings at both wavelengths, but with slightly narrower rings at the longer wavelength. Along a faint ring at 42 au, we identify two excess emission features at ∼10σ significance at both wavelengths: one as an unresolved clump and the other as an extended arc, separated by roughly 120° in azimuth. The clump is unlikely to be a circumplanetary disk (CPD) as the emission peak shifts between the two wavelengths even after accounting for orbital motion. Instead, the morphology of the 42 au ring strongly resembles the characteristic horseshoe orbit produced in planet–disk interaction models, where the clump and the arc trace dust accumulation around Lagrangian points L 4 and L 5, respectively. The shape of the 42 au ring, dust trapping in the outer adjacent ring, and the coincidence of the horseshoe ring location with a gap in near-IR scattered light, are all consistent with the scenario of planet sculpting, with the planet likely having a mass between those of Neptune and Saturn. We do not detect pointlike emission associated with a CPD around the putative planet location (0.″27 in projected separation from the central star at a position angle of ∼60°), with upper limits of 70 and 33 μJy at 0.88 and 1.3 mm, respectively, corresponding to dust mass upper limits of 0.02–0.03 M ⊕.

Distributions of gas and small and large grains in the LkHα 330 disk trace a young planetary system,

Planets that are forming around young stars are expected to leave clear imprints in the distribution of the gas and dust of their parental protoplanetary disks. In this paper, we present new scattered light and millimeter observations of the protoplanetary disk around LkHα 330, using SPHERE/VLT and ALMA, respectively. The scattered-light SPHERE observations reveal an asymmetric ring at around 45 au from the star in addition to two spiral arms with similar radial launching points at around 90 au. The millimeter observations from ALMA (resolution of 0.06″ × 0.04″) mainly show an asymmetric ring located at 110 au from the star. In addition to this asymmetry, there are two faint symmetric rings at 60 au and 200 au. The 12CO, 13CO, and C18O lines seem to be less abundant in the inner disk (these observations have a resolution of 0.16″ × 0.11″). The 13CO peaks at a location similar to the inner ring observed with SPHERE, suggesting that this line is optically thick and traces variations of disk temperature instead of gas surface-density variations, while the C18O peaks slightly further away at around 60 au. We compare our observations with hydrodynamical simulations that include gas and dust evolution, and conclude that a 10 MJup mass planet at 60 au and in an eccentric orbit (e = 0.1) can qualitatively explain most of the observed structures. A planet in a circular orbit leads to a much narrower concentration in the millimeter emission, while a planet in a more eccentric orbit leads to a very eccentric cavity as well. In addition, the outer spiral arm launched by the planet changes its pitch angle along the spiral due to the eccentricity and when it interacts with the vortex, potentially appearing in observations as two distinct spirals. Our observations and models show that LkHα 330 is an interesting target to search for (eccentric-) planets while they are still embedded in their parental disk, making it an excellent candidate for studies on planet-disk interaction.

Damping the phase segregation in mixed halide perovskites: Influence of X-site anion

It has been observed that presence of chlorine in perovskite nanocrystals (NCs), incorporates stability whereas bromine content enhances radiative lifetime that makes mixed halides competitive candidates for both higher stabilities and longer radiative lifetimes as compared to pristine cesium lead halides. In this study, we demonstrate an important, yet least explored phenomenon observed in mixed halides perovskites of photo-induced phase segregation, which unfortunately limits the practical utility of mixed halide perovskites. This study reveals that phase segregation becomes more prominent on decreasing bromine content in mixed halide CsPbBr3-xClx perovskites, when bromine content is 50% or less, it shows no phase segregation. Triple halide perovskite ABX3-y-zYyZz NCs have been synthesized to mitigate the phase segregation. The grain size of the synthesized NCs exists in the range of 20–25 nm. The selected area electron diffraction exhibits the faint rings of the CsPbBr1.5Cl1.5 indicating the presence of defects in NCs and the X-rays diffraction analysis confirms the NCs exist in monoclinic crystal structure. Mixed halides perovskites have same crystal structure but exhibit a slight shift in 2θ values. The trend in stability follows the order as, CsPbBr3-xClx > CsPbCl3 > CsPbBr3 that is estimated by the values of octahedral factor (μ) and tolerance factor (t). The UV–Vis and steady-state photoluminescence (PL) analysis depict a blue-shift in the spectra by substituting bromine with chlorine in CsPbBr3. The PL kinetics analysis predicts the CsPbBr2.5Cl0.5 exhibits the longest average PL lifetime amongst all other CsPbBr3-xClx perovskites NCs. Our study provides insights in designing stable mixed halides perovskites by suppressing the phase segregation.

Constraining the properties of the potential embedded planets in the disk around HD 100546

Context. The protoplanetary disk around the star HD 100546 displays prominent substructures in the form of two concentric rings. Recent observations with the Atacama Large Millimeter/sub-millimeter Array (ALMA) have revealed these features with high angular resolution and have resolved the faint outer ring well. This allows us to study the nature of the system further. Aims. Our aim is to constrain some of the properties of potential planets embedded in the disk, assuming that they induce the observed rings and gaps. Methods. We present the self-calibrated 0.9 mm ALMA observations of the dust continuum emission from the circumstellar disk around HD 100546. These observations reveal substructures in the disk that are consistent with two rings, the outer ring being much fainter than the inner one. We reproduced this appearance closely with a numerical model that assumes two embedded planets. We varied planet and disk parameters in the framework of the planet-disk interaction code FARGO3D and used the outputs for the gas and dust distribution to generate synthetic observations with the code RADMC-3D. Results. From this comparison, we find that an inner planet located at r1 = 13 au with a mass M1 = 8 MJup and an outer planet located at r2 = 143 au with a mass M2 = 3 MJup leads to the best agreement between synthetic and ALMA observations (deviation less than 3σ for the normalized radial profiles). To match the very low brightness of the outer structure relative to the inner ring, the initial disk gas surface density profile needs to follow an exponentially tapered power law (self-similar solution), rather than a simple power-law profile.

ALMA 870 μm continuum observations of HD 100546

This paper reports on a new analysis of archival ALMA 870 μm dust continuum observations. Along with the previously observed bright inner ring (r ~ 20–40 au), two addition substructures are evident in the new continuum image: a wide dust gap, r ~ 40–150 au, and a faint outer ring ranging from r ~ 150 au to r ~ 250 au and whose presence was formerly postulated in low-angular-resolution ALMA cycle 0 observations but never before observed. Notably, the dust emission of the outer ring is not homogeneous, and it shows two prominent azimuthal asymmetries that resemble an eccentric ring with eccentricity e = 0.07. The characteristic double-ring dust structure of HD 100546 is likely produced by the interaction of the disk with multiple giant protoplanets. This paper includes new smoothed-particle-hydrodynamic simulations with two giant protoplanets, one inside of the inner dust cavity and one in the dust gap. The simulations qualitatively reproduce the observations, and the final masses and orbital distances of the two planets in the simulations are 3.1 MJ at 15 au and 8.5 MJ at 110 au, respectively. The massive outer protoplanet substantially perturbs the disk surface density distribution and gas dynamics, producing multiple spiral arms both inward and outward of its orbit. This can explain the observed perturbed gas dynamics inward of 100 au as revealed by ALMA observations of CO. Finally, the reduced dust surface density in the ~40–150 au dust gap can nicely clarify the origin of the previously detected H2O gas and ice emission.

VLA Resolves Unexpected Radio Structures in the Perseus Cluster of Galaxies

Abstract We present new deep, high-resolution, 1.5 GHz observations of the prototypical nearby Perseus galaxy cluster from the Karl G. Jansky Very Large Array. We isolate for the first time the complete tail of radio emission of the bent-jet radio galaxy NGC 1272, which had been previously mistaken to be part of the radio mini-halo. The possibility that diffuse radio galaxy emission contributes to mini-halo emission may be a general phenomenon in relaxed cool-core clusters, and should be explored. The collimated jets of NGC 1272 initially bend to the west, and then transition eastward into faint, 60 kpc long extensions with eddy-like structures and filaments. We suggest interpretations for these structures that involve bulk motions of intracluster gas, the galaxy’s orbit in the cluster including projection effects, and the passage of the galaxy through a sloshing cold front. Instabilities and turbulence created at the surface of this cold front and in the turbulent wake of the infalling host galaxy most likely play a role in the formation of the observed structures. We also discover a series of faint rings, southeast of NGC 1272, which are a type of structure that has never been seen before in galaxy clusters.

ALMA Observation of the Protoplanetary Disk around WW Cha: Faint Double-peaked Ring and Asymmetric Structure

Abstract We present Atacama Large Millimeter/submillimeter Array (ALMA) Band 6 observations of dust continuum emission of the disk around WW Cha. The dust continuum image shows a smooth disk structure with a faint (low-contrast) dust ring, extending from ∼40 au to ∼70 au, not accompanied by any gap. We constructed the simple model to fit the visibility of the observed data by using the Markov Chain Monte Carlo (MCMC) method and found that the bump (we call the ring without the gap the bump) has two peaks at 40 au and 70 au. The residual map between the model and observation indicates asymmetric structures at the center and the outer region of the disk. These asymmetric structures are also confirmed by model-independent analysis of the imaginary part of the visibility. The asymmetric structure at the outer region is consistent with a spiral observed by SPHERE. To constrain physical quantities of the disk (dust density and temperature), we carried out radiative transfer simulations. We found that the midplane temperature around the outer peak is close to the freezing temperature of CO on water ice (∼30 K). The temperature around the inner peak is about 50 K, which is close to the freezing temperature of H2S and also close to the sintering temperature of several species. We also discuss the size distribution of the dust grains using the spectral index map obtained within the Band 6 data.

Annular substructures in the transition disks around LkCa 15 and J1610

We present high-resolution millimeter continuum ALMA observations of the disks around the T Tauri stars LkCa 15 and 2MASS J16100501-2132318 (hereafter, J1610). These transition disks host dust-depleted inner regions, which have possibly been carved by massive planets, and they are of prime interest to the study of the imprints of planet-disk interactions. While at moderate angular resolution, they appear as a broad ring surrounding a cavity, the continuum emission resolves into multiple rings at a resolution of ~60 × 40 mas (~7.5 au for LkCa 15, ~6 au for J1610) and ~7μJy beam−1rms at 1.3 mm. In addition to a broad extended component, LkCa 15 and J1610 host three and two narrow rings, respectively, with two bright rings in LkCa 15 being radially resolved. LkCa 15 possibly hosts another faint ring close to the outer edge of the mm emission. The rings look marginally optically thick, with peak optical depths of ~0.5 (neglecting scattering), in agreement with high angular resolution observations of full disks. We performed hydrodynamical simulations with an embedded, sub-Jovian-mass planet and show that the observed multi-ringed substructure can be qualitatively explained as the outcome of the planet-disk interaction. We note, however, that the choice of the disk cooling timescale alone can significantly impact the resulting gas and dust distributions around the planet, leading to different numbers of rings and gaps and different spacings between them. We propose that the massive outer disk regions of transition disks are favorable places for planetesimals, and possibly second-generation planet formation of objects with a lower mass than the planets carving the inner cavity (typically fewMJup), and that the annular substructures observed in LkCa 15 and J1610 may be indicative of planetary core formation within dust-rich pressure traps. Current observations are compatible with other mechanisms contributing to the origin of the observed substructures, in particular with regard to narrow rings generated (or facilitated) at the edge of the CO and N2snowlines.

Topographic synthesis of arbitrary surfaces with vortex Jinc functions.

When a circular aperture is uniformly illuminated, it is possible to observe in the far field an image of a bright circle surrounded by faint rings known as the Airy pattern or Airy disk. This pattern is described by the first-order Bessel function of the first type divided by its argument expressed in circular coordinates. We introduce the higher-order Bessel functions with a vortex azimuthal factor to propose a family of functions to generalize the function defining the Airy pattern. These functions, which we call vortex Jinc functions, happen to form an orthogonal set. We use this property to investigate their usefulness in fitting various surfaces in a circular domain, with applications in precision optical manufacturing, wavefront optics, and visual optics, among others. We compare them with other well-known sets of orthogonal functions, and our findings show that they are suitable for these tasks and can pose an advantage when dealing with surfaces that concentrate a considerable amount of their information near the center of a circular domain, making them suitable applications in visual optics or analysis of aberrations of optical systems, for instance, to analyze the point spread function.

The Detection of Dust Gap-ring Structure in the Outer Region of the CR Cha Protoplanetary Disk

Abstract We observe the dust continuum at 225 GHz and CO isotopologue (12CO, 13CO, and C18O) J = 2–1 emission lines toward the CR Cha protoplanetary disk using the Atacama Large Millimeter/submillimeter Array. The dust continuum image shows a dust gap-ring structure in the outer region of the dust disk. A faint dust ring is also detected around 120 au beyond the dust gap. The CO isotopologue lines indicate that the gas disk is more extended than the dust disk. The peak brightness temperature of the 13CO line shows a small bump around 130 au, while 12CO lines do not. We investigate two possible mechanisms for reproducing the observed dust gap-ring structure and a gas temperature bump. First, the observed gap structure can be opened by a Jupiter-mass planet using the relation between the planet mass and the gap depth and width. Meanwhile, the radiative transfer calculations based on the observed dust surface density profile show that the observed dust ring could be formed by dust accumulation at the gas temperature bump, that is, the gas pressure bump produced beyond the outer edge of the dust disk.

Amorphous iron formation following occupancy of iron atoms in vacant sites of epsilon-iron that transformed from alpha-iron during rubbing in a low vacuum

The main purpose of this paper is to present two TEM diffraction patterns taken from a layer (more than 100 μm thick) of piled-up adhered wear debris on a rubbed surface. The unidirectional rubbing was made in a low vacuum, regularly separating the slider from the specimen. The specimen and the slider were α-iron. One of the diffraction patterns consists of large spots and halo rings and the other consists of small faint spots and halo rings. The latter seems to be the state just before the perfect amorphization. All the spots in the diffraction patterns correspond to the structure formed due to the occupancy of iron atoms in O and T sites of ε-iron. Neither this way of amorphization nor the occupied structure mentioned above has not been reported. Both the amorphous state and the occupied structure remain at ambient conditions. The mechanism of high-pressure generation that transformed α-iron to ε-iron and the generation of high tensile stress that breaks the atomic bonds in wear debris are presented. The latter is considered to have enabled the occupancy.

1747 Rare Case of Esophagitis Dissecans Superficialis Mimicking Eosinophilic Esophagitis Treated With PPI

INTRODUCTION: Esophagitis dissecans superficialis (EDS) is a rare condition characterized classically by sloughing of the esophageal mucosa. EDS is a benign condition that usually resolves without lasting pathology. EDS can be associated with medications, chemical irritants, hot beverages, autoimmune diseases. Here we present a case of EDS which mimicked Eosinophilic esophagitis on endoscopy. CASE DESCRIPTION/METHODS: 76 y old male with PMH of CAD on ASA presented with chief complain of dysphagia to solid food underwent EGD that revealed mucosal friability, non-obstructing Schatzki ring, faint mucosal rings. The esophagus was dilated with 18 Fr savory dilator. Biopsies from mid and distal esophagus showed nonspecific inflammation with no intramucosal eosinophils. EGD was repeated 3 months later while he was taking PPI BID. Repeat EGD showed esophagus with circumferential rings, congestions, friability and a thin white membrane lifting from the mucosa. Biopsies from mid and distal esophagus showed splitting of squamous mucosa, focal lymphocytic infiltration and diffuse parakeratosis consistent with EDS. He was continued with PPI BID with the improvement of symptoms. DISCUSSION: Classical EDS has been characterized by stripped, whitish mucosa with or without bleeding, vertical fissures and circumferential cracks. EDS is associated with medications such as bisphosphonates or NSAIDs, chemical irritants, celiac disease, hot beverages, autoimmune bullous dermatoses or idiopathy. Commonly presents as dysphagia, anemia, pain, and heartburn. It is unclear if 81 mg ASA taken by our patient is a culprit, as he did not have any other known risk factor. Treatment includes PPI and discontinuing precipitating factors and medications. In this case, endoscopic findings initially mimicked EoE, however, repeat EGD with biopsies revealed underlying EDS.

Paecilomyces niveus: Pathogenicity in the Orchard and Sensitivity to Three Fungicides.

Paecilomyces rot of apples is a postharvest disease caused by the thermotolerant fungus Paecilomyces niveus (Byssochlamys nivea). The etiology of disease and the activity of fungicides against P. niveus are not yet well understood. This study evaluated the ability of P. niveus to infect 'Gala' apples growing in a conventionally managed orchard. In addition, the sensitivity of P. niveus isolates to postharvest fungicides difenoconazole, fludioxonil, and pyrimethanil was characterized for isolates from both agricultural and nonagricultural environments. Apples were wounded and mock-inoculated or inoculated with P. niveus in early July. At the time of harvest, 8 weeks after wounding, the inoculated apples had significantly larger lesions than mock-inoculated apples (P < 0.005). The average diameter of lesions on wound-inoculated apples was 11.17 mm ± 6.82 SD, while the average diameter of mock-inoculated lesions was 3.34 mm ± 1.85 SD. Disease symptoms in the orchard were similar to postharvest symptoms of Paecilomyces rot. Symptoms included a brown, flattened, circular lesion with faint concentric rings. The necrosis of mesocarp was firm and roughly U-shaped. Baseline isolates of P. niveus, from nonagricultural environments, were used to determine the effective fungicide dose at which growth was inhibited by 50% (EC50). Furthermore, fungicide sensitivity of P. niveus isolates was examined using relative growth assays at the mean baseline EC50 values to compare baseline isolates with isolates obtained from commercial apple orchards where they were likely exposed to fungicides. Among the exposed isolates, reduced sensitivity to all fungicides was observed, but significant differences between baseline and exposed isolates were only observed with fludioxonil (P < 0.0001). This is the first report demonstrating that P. niveus can infect apples that are wound-inoculated in the orchard and that isolates from agricultural environments are less sensitive to common fungicides, especially fludioxonil. This finding may have implications for the control of this postharvest diseases. Whether natural infections of apples by P. niveus is initiated in the orchard or during postharvest has yet to be determined.