1,920 research outputs found
Lyman alpha line shapes from electron impact H2 dissociative processes in the Jovian auroral zone
Over the past two years several Lyman alpha line profile spectra of Jupiter were obtained using the International Ultraviolet Explorer (IUE) telescope. Several different regions of the planet were observed including the auroral zone, the low and mid latitudes, and the equatorial region which includes the Lyman alpha bulge region. These results have presented a very interesting picture of atomic hydrogen on Jupiter with explanations that range from ion outflow in the auroral zone to large thermospheric winds at low and mid latitudes. New data are needed to address the outstanding questions. Almost certainly, high resolution spectra from the Hubble Space Telescope will play a role in new observations. Better data also require better models, and better models require new laboratory data as inputs. The purpose of this program is two-fold: (1) to introduce a method by which new laboratory electron impact measurements of H2 dissociation can be used to calculate both the slow and fast H(S-2) and H(P-2) fragments in an H2 atmosphere; and (2) to determine the predicted Lyman alpha line shape that would result from electron impact production of these dissociative fragments in the Jovian auroral zone
Adenocarcinoma of the Ethmoid Sinus Presenting with Epiphora
Abstract: Low-grade non-intestinal type adenocarcinomas are rare tumors that arise from the surface epithelium of the sinonasal tract. They frequently involve the ethmoid sinus, the nasal cavity, and the maxillary sinus. These tumors present at a mean age range of 37-53 years with various non-specific symptoms including nasal obstruction and epistaxis. We report the first case of a low-grade non-intestinal type sinonasal-adenocarcinoma of the ethmoid sinus presenting with persistent unilateral epiphora.
Case Presentation: A 67-year-old man presented with complaints of bloody tearing and right medial canthus swelling for several months. Examination of the area revealed a small bump beneath the skin which burst with a green mucopurulent discharge on gentle palpation. Computed tomography (CT) scans revealed a large growth in the ethmoid sinus invading into the right medial orbit and extending into the maxilla. Histopathology (H&E) demonstrated a cribriform pattern, moderately graded nuclei, and eosinophilia consistent with non-intestinal type sinonasal adenocarcinoma. The patient underwent orbital exenteration and large sinus resection.
Discussion: Cancers of the paranasal sinuses are extremely uncommon and account for just 1% of all human cancers. Low-grade non-intestinal type adenocarcinoma is an extremely rare subtype that has only been reported a handful of times. Synonyms in the literature include terminal tubulus adenocarcinoma, sinonasal tubulopapillary low-grade adenocarcinoma, and sinonasal seromucinous adenocarcinoma. Microscopic analysis is key for differentiation of this tumor type from other similar sinonasal malignancies as well as for prognostication purposes. Histologically, non-ITAC is recognized by its trabecular, cribaform, or papillary growth pattern and the single layer of uniform columnar or cuboidal cells that line its glands. Pleomorphic nuclei and mitotic figures are rarely seen in this subtype. Immunohistochemically, non-ITAC is characterized by positive CK7 staining and/or negative CDX-2 and CK-20 staining. Differential diagnoses to consider include intestinal type adenocarcinoma (ITAC), acinic cell carcinoma, and oncocytic Schneiderian papilloma. ITAC is an aggressive malignancy that is differentiated from non-ITAC on the basis of its resemblance to the mucosa found in the small and large intestine, its high-grade histologic appearance, and cellular expression of CDX-2. Distinguishing the two tumors types is of crucial clinical importance given that low-grade non-ITAC has not, to date, displayed metastatic behavior while several instances of low-grade ITAC metastases have been reported. Rarely, non-intestinal type adenocarcinoma may be confused with oncocytic Schneiderian papillomas. However, the epithelium of oncocytic Schneiderian papillomas are multilayered and lack glandular lumina. The presenting clinical symptoms of non-ITAC vary, however the most common reported symptoms are nasal obstruction and epistaxis. In our case, the patient presented with persistent unilateral epiphora which has not, to date, been reported in association with this tumor subtype. The mainstay in treatment of low-grade non-ITAC includes surgery followed by radiation therapy. Overall, the prognosis of patients with non-ITAC is good and rarely does death occur due to the disease.https://scholarlycommons.henryford.com/merf2020caserpt/1125/thumbnail.jp
Processes of equatorial thermal structure at Jupiter: An analysis of the Galileo temperature profile with a three‐dimensional model
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/94956/1/jgre1925.pd
Ultraviolet observations of the Saturnian north aurora and polar haze distribution with the HST-FOC
Near simultaneous observations of the Saturnian H2 north ultraviolet aurora and the polar haze were made at 153 nm and 210 nm respectively with the Faint Object Camera on board the Hubble Space Telescope. The auroral observations cover a complete rotation of the planet and, when co-added, reveal the presence of an auroral emission near 80 deg N with a peak brightness of about 150 kR of total H2 emission. The maximum optical depth of the polar haze layer is found to be located approximately 5 deg equatorward of the auroral emission zone. The haze particles are presumably formed by hydrocarbon aerosols initiated by H2+ auroral production. In this case, the observed haze optical depth requires an efficiency of aerosol formation of about 6 percent, indicating that auroral production of hydrocarbon aerosols is a viable source of high-latitude haze
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