A Constraint on the Amount of Hydrogen from the CO Chemistry in Debris Disks

The faint CO gases in debris disks are easily dissolved into C by UV irradiation, while CO can be reformed via reactions with hydrogen. The abundance ratio of C/CO could thus be a probe of the amount of hydrogen in the debris disks. We conduct radiative transfer calculations with chemical reactions for debris disks. For a typical dust-to-gas mass ratio of debris disks, CO formation proceeds without the involvement of H$_2$ because a small amount of dust grains makes H$_2$ formation inefficient. We find that the CO to C number density ratio depends on a combination of $n_\mathrm{H}Z^{0.4}\chi^{-1.1}$, where $n_\mathrm{H}$ is the hydrogen nucleus number density, $Z$ is the metallicity, and $\chi$ is the FUV flux normalized by the Habing flux. Using an analytic formula for the CO number density, we give constraints on the amount of hydrogen and metallicity for debris disks. CO formation is accelerated by excited H$_2$ either when the dust-to-gas mass ratio is increased or the energy barrier of chemisorption of hydrogen on the dust surface is decreased. This acceleration of CO formation occurs only when the shielding effects of CO are insignificant. In shielded regions, the CO fractions are almost independent of the parameters of dust grains.Comment: 29pages, 13figures, accepted for Ap

Vertical Structure of the Transition Zone from Infalling Rotating Envelope to Disk in the Class 0 Protostar, IRAS04368+2557

We have resolved for the first time the radial and vertical structure of the almost edge-on envelope/disk system of the low-mass Class 0 protostar L1527. For that, we have used ALMA observations with a spatial resolution of 0.25$^{\prime\prime}$$\times$0.13$^{\prime\prime}$ and 0.37$^{\prime\prime}$$\times$0.23$^{\prime\prime}$ at 0.8 mm and 1.2 mm, respectively. The L1527 dust continuum emission has a deconvolved size of 78 au $\times$ 21 au, and shows a flared disk-like structure. A thin infalling-rotating envelope is seen in the CCH emission outward of about 150 au, and its thickness is increased by a factor of 2 inward of it. This radius lies between the centrifugal radius (200 au) and the centrifugal barrier of the infalling-rotating envelope (100 au). The gas stagnates in front of the centrifugal barrier and moves toward vertical directions. SO emission is concentrated around and inside the centrifugal barrier. The rotation speed of the SO emitting gas is found to be decelerated around the centrifugal barrier. A part of the angular momentum could be extracted by the gas which moves away from the mid-plane around the centrifugal barrier. If this is the case, the centrifugal barrier would be related to the launching mechanism of low velocity outflows, such as disk winds

Primordial or Secondary? Testing models of debris disk gas with ALMA

The origin and evolution of gas in debris disks is still not well understood. Secondary gas production from cometary material or a primordial origin have been proposed. So far, observations have mostly concentrated on CO, with only few C observations available. We create an overview of the C and CO content of debris disk gas and use it test state-of-the-art models. We use new and archival ALMA observations of CO and CI emission, complemented by CII data from Herschel, for a sample of 14 debris disks. This expands the number of disks with ALMA measurements of both CO and CI by ten disks. We present new detections of CI emission towards three disks: HD 21997, HD 121191 and HD 121617. We use a simple disk model to derive gas masses and column densities. We find that current state-of-the-art models of secondary gas production overpredict the neutral carbon content of debris disk gas. This does not rule out a secondary origin, but might indicate that the models require an additional C removal process. Alternatively, the gas might be produced in transient events rather than a steady-state collisional cascade. We also test a primordial gas origin by comparing our results to a simplified thermo-chemical model. This yields promising results, but more detailed work is required before a conclusion can be reached. Our work demonstrates that the combination of C and CO data is a powerful tool to advance our understanding of debris disk gas.Comment: 90 pages, 60 figures. Accepted for publication in ApJ. version 2: additional acknowledgement. versions 3, 4: minor edit

Manifestações Dermatológicas como Único Sintoma em Paciente com COVID-19/Dermatological Disorders as the Only Symptom in Patient with COVID-19

Introdução: Descrito pela primeira vez em 2019, o novo coronavírus SARS-CoV-2 se tornou responsável pelo estado de pandemia global desde 11 de março de 2020. Sua rápida disseminação pelas fronteiras geográficas fez com que COVID-19 fosse diagnosticado em mais de 36 milhões de pessoas em todo o mundo até a presente data. Relato de caso: Paciente 14 anos, previamente hígida, iniciou quadro de petéquias em membros inferiores, sem quaisquer sintomas associados, com piora progressiva e surgimento de novas lesões desde então, que se disseminaram pelo tegumento, com acometimento inclusive de mãos, pés e cavidade oral. Aventadas hipóteses de coxsackiose e COVID-19. Realizado RT-PCR que resultou positivo para SARS-CoV-2, concluindo o diagnóstico. Discussão: O entendimento das manifestações cutâneas do COVID-19 iniciou com Recalcati em maio de 2020 e continua até hoje, sendo importante ferramenta no diagnóstico dos pacientes oligossintomático e na interrupção da cadeia de transmissão precocemente

About the rumination of negative and positive event in the university students : From the comparison of the content of the event, the timecourse and the mental occupation levels

\u22Rumination\u22 can be defined as \u22thinking repeatedly\u22 about a certain event. This study was examined from the aspect of the content of the event, time course, and mental occupation level about the phenomenon of \u22rumination\u22. The difference in the rumination on negative events and positive events, and the difference in the ruminationover the time course were examined in study_1. The relation to the frequency of rumination and the mental occupation level were examined study_2. The results showed that at the time teh event occured, it was easier to ruminate on a negative event and to be preoccupied eith it than to do the same with a positive event. However, as time passes, it is easier to ruminate on a positive event than on a negative one ; moreover, this change is also more sensitive

Alternating Current (AC) Iontophoretic Transport across Human Epidermal Membrane: Effects of AC Frequency and Amplitude

Purpose As a continuing effort to understand the mechanisms of alternating current (AC) transdermal iontophoresis and the iontophoretic transport pathways in the stratum corneum (SC), the objectives of the present study were to determine the interplay of AC frequency, AC voltage, and iontophoretic transport of ionic and neutral permeants across human epidermal membrane (HEM) and use AC as a means to characterize the transport pathways. Materials and Methods Constant AC voltage iontophoresis experiments were conducted with HEM in 0.10 M tetraethyl ammonium pivalate (TEAP). AC frequencies ranging from 0.0001 to 25 Hz and AC applied voltages of 0.5 and 2.5 V were investigated. Tetraethyl ammonium (TEA) and arabinose (ARA) were the ionic and neutral model permeants, respectively. In data analysis, the logarithm of the permeability coefficients of HEM for the model permeants was plotted against the logarithm of the HEM electrical resistance for each AC condition. Results As expected, linear correlations between the logarithms of permeability coefficients and the logarithms of resistances of HEM were observed, and the permeability data were first normalized and then compared at the same HEM electrical resistance using these correlations. Transport enhancement of the ionic permeant was significantly larger than that of the neutral permeant during AC iontophoresis. The fluxes of the ionic permeant during AC iontophoresis of 2.5 V in the frequency range from 5 to 1,000 Hz were relatively constant and were approximately 4 times over those of passive transport. When the AC frequency decreased from 5 to 0.001 Hz at 2.5 V, flux enhancement increased to around 50 times over passive transport. Conclusion While the AC frequency for achieving the full effect of iontophoretic enhancement at low AC frequency was lower than anticipated, the frequency for approaching passive diffusion transport at high frequency was higher than expected from the HEM morphology. These observations are consistent with a transport model of multiple barriers in series and the previous hypothesis that the iontophoresis pathways across HEM under AC behave like a series of reservoirs interconnected by short pore pathways

Histopathological evaluation of cesarean scar defect in women with cesarean scar syndrome

Abstract Purpose To explore the histopathological findings of cesarean scar defect (CSD) and the immunological component in women with cesarean scar syndrome (CSS). Methods This retrospective study was conducted in a university hospital and a public hospital. A total of 63 patients with secondary infertility due to CSS who underwent laparoscopic resection of the CSD lesion were enrolled (CSS group), and 21 patients who underwent hysterectomy with a history of cesarean section were enrolled as control (non‐CSS group). We compared the differences in histopathological findings of CSD lesions by hematoxylin and eosin staining and immunohistochemistry for CD3, CD20, CD56, CD68, CD138, myeloperoxidase, and tryptase between the two groups. Results The frequency of presence of endometrium on the CSD surface was significantly lower (p = 0.0023) and that of adenomyosis was significantly higher (p = 0.0195) in the CSS group than in the non‐CSS group. The number of CD3‐, CD20‐, CD68‐, and tryptase‐positive cells was significantly lower in the CSS group than in the non‐CSS group; however, the number of CD138‐positive cells was significantly higher in the CSS group (p = 0.0042). Conclusions This study suggested that the absence of endometrium, presence of adenomyosis, and chronic inflammation in CSD contributes to secondary infertility due to CSS