Mapping the present-day chemical abundance structure of the Solar neighbourhood: O & Si

Context. Large scale chemical abundance gradients in the Galactic disks, small-scale abundance structures, and the mean chemical abundance values in the Solar vicinity, are important constraints to Galactic chemo-dynamical formation and evolution models. The formation and evolution of stars, and interstellar gas and dust depends on the distribution and evolution of matter in the Galaxy. Therefore, metallicity structures within the Milky Way can be mapped from the abundance analysis of its gas and stars. Data. A sample of 379 mostly spectral type B main sequence stars within 1.5 kpc radius from the Sun, was observed with the MIKE high-resolution spectrograph on the Magellan 6.5-m telescope on Las Campanas in Chile in 2007. Projected rotational velocities and photometric effective temperatures were determined for these stars by Bragança et al. (2012). B-stars are good indicators for present-day cosmic abundances due to their short lifetimes. They preserve the interstellar medium abundances, which they were born from, in the photosphere, and they do not migrate far from their birth environment. Aims. The purpose of this Master’s project was to start mapping the present-day silicon and oxygen abundance structure of the Solar neighbourhood, by determining the stellar atmospheric parameters, and Si and O abundances, for the low-rotating (< 22 km/s ) subsample. The thesis at hand is part of an international study aimed to determine the elemental abundances of B-type main sequence stars near the Solar vicinity and in the outer Galactic disk (Bragança et al. 2012, 2015; Garmany et al. 2015, Bragança et al. in prep.). Methods. Line-profile fitting of Si, O and Balmer lines, with full NLTE synthetic spectra, and an iterative analysis methodology, was used to constrain stellar atmospheric parameters and elemental abundances at high accuracy and precision. Results & Conclusions. With this Master’s thesis, an extensive mapping the Solar neighbourhood has begun: stellar parameters, and Si and O abundances were established for 17 stars. The mean elemental abundance of the Solar neighbourhood of a 1.25 kpc radius, was found to be 7.42±0.13 dex for silicon and 8.73±0.06 dex for oxygen. The results are consistent with the cosmic abundance standard from Nieva & Przybilla (2012) within error-bars, and provide reliable present-day anchor points for Galactic chemical evolution models. However, the stars in our sample have on average smaller abundance values and the Solar neighbourhood seems to be more heterogeneous, than determined by Nieva & Przybilla (2012) study. Small scale abundance structures were not discovered, due to yet small sample size. In the future, other low-rotating stars in the observed stellar sample will be analysed, up to a v sin i = 80 km/s limit. This would amount to about 100 stars. Combined with Gaia DR2 positions, and chemical abundances for the fast rotating B-type stars in the Solar vicinity (Cazorla et al. 2017), would provide an unprecedented view of the present-day Solar neighbourhood.Vår galax, Vintergatan, innehåller bortåt 200 miljarder stjärnor av varierande åldrar och storlekar. Under en mörk och klar natt kan man se ungefär 2000 med blotta ögat. Detta är en liten del av det stora hela, men tillräckligt för att stimulera människors nyfikenhet. Vad är de gjorda av, och varför är de där de är? Enkla frågor, som har väldigt komplexa svar. Genom att kartlägga strukturen och den kemiska sammansättningen hos den unga nuvarande stjärnpopulationen i solens närhet avser detta arbete att besvara den första frågan och ge ytterligare ledtrådar till den andra. Vintergatans ursprung och utveckling finns bevarat i form av den kemiska sammansättningen och kinematiska egenskaperna hos dess stjärnor och gas, så genom att bestämma stjärnors kemiska sammansättning kan man få information om den miljö som de bildades från. Detta arbete har använt sig av massiva (2–16 Solmassa) huvudseriestjärnor för att bestämma den nutida ymnigheten av syre och kisel i solens närhet. Massiva stjärnor är utmärkta indikatorer för Vintergatans nutida kemiska sammansättning, av flera anledningar. För det första så har massiva stjärnor korta livstider, några miljoner till några tiotals miljoner år, att jämföras med Vintergatans ålder som är runt 13 miljarder år. För det andra så befinner de sig fortfarande på den plats de bildades, detta på grund av att de inte hunnit migrera nämnvärt på de få miljoner år de levt. För det tredje så är de väldigt luminösa, och således lätta att observera, vilket beror på att de har så höga temperaturer (10000–30000 K). Ymnigheten av olika grundämnen i atmosfärerna hos dessa stjärnor representerar den kemiska sammansättning som det interstellära mediet hade när de bildades. Den nutida sammansättningen av olika grundämnen i solens närhet utgör viktiga randvillkor för galaktiska kemisk-dynamiska utvecklingsmodeller eftersom de man vill att de skall resultera i realistiska Vintergatsmodeller. Riktmärket för Vintergatan är solens närhet som är det område som kan studeras med största noggrannhet och precision, eftersom stjärnorna är näraliggande och enkla att observera. Mer än 370 näraliggande (inom en radie av 1.5 kpc) massiva stjärnor observerades för detta projekt år 2007. Grova uppskattningar för stjärnornas rotationshastigheter och effektiva temperaturer gjordes av Bragança et al. (2012). Denna Masteruppsats har som mål att bestämma stjärnparametrar (effektiv temperature, ytgravitation, projicerad rotationsgahstighet, mikro- och makroturbulenshastigheter) och grundämneshalter på ett konsekvent sätt för de stjärnor som har låga rotationshastigheter. De observerade spektrumen jämfördes med syntetiskt spektrum, som genererats med hjälp av modellatmosfärer och atommodeller, för att analysera formerna på spektrallinjer. En linje-för-linje-baserad anpassningsmetod för kisel, syre, och vätelinjer användes, och statistiska metoder för att bestämma stjärnparametrar och grundämneshalter. Denna metod är väldigt tidskrävande - att analysera en stjärna tar några dagar upp till en vecka - men berikande. I detta Masterprojekt har 17 stjärnor i solens närhet analyserats för att kartlägga kisel- och syrehalter i solens närhet. Vi fann att solens närhet verkar vara aningen mindre homogen än vad som tidigare rapporterats. Dock så överensstämmer medelhalterna för solens närhet med tidigare liknande studier, samt med dessa grundämnens halter i solen. På grund av den kemiska utvecklingen i Vintergatan så borde yngre stjärnor generellt sett ha högre grundämneshalter än solen som är äldre. Dessa resultat antyder att solen bildades i de inre delarna av Vintergatan, som är mer berikade, och sedan migrerade till dess nuvarande position 8 kpc från Vintergatans centrum. Några småskaliga ymnighetsvariantioner kunde inte detekteras, antagligen beroende på det ännu begränsade antal stjärnor som analyserats.Framtida planer innefattar att analysera alla stjärnor i samplet, upp mot 100 stjärnor. Med denna Mastersuppsats har det detaljerade kartläggandet av solens närhet börjat

Physical Properties of the Nova Remnant Nova Persei 1901

http://www.ester.ee/record=b448451

Papillomavirus Infection and Prevention: How Much Does the Sicilian Population Know? An Observational Study

Human papillomavirus is a sexually transmitted virus that is responsible not only for uterine cervical cancer, but also for the oral and oropharyngeal cancers. In this latter case, the virus indiscriminately affects both sexes at any age. Vaccination plays a key role in preventing infection and its possible consequences. Therefore, this study aimed to assess the degree of awareness of papillomavirus infection and its possible prevention in the Sicilian population. A prospective observational study was carried out on the Sicilian population through a self-administered questionnaire, consisting of 10 multiple-choice questions. The survey lasted from June 2021 to December 2021. A total of 844 respondents were included: 60.90% were female and 53.55% were aged between 21 and 30 years. Most of the surveyed population knew about the virus and the existence of the vaccine, however, many of them did not know about virus's effects on the oral and oropharyngeal sites (49.17%), or about the indication for vaccination for males (39.69%). Oral and oropharyngeal papillomavirus-related cancers are an increasingly frequent finding, especially in young adults. Therefore, it is necessary and quite mandatory to educate the population about the risks that certain voluptuous habits may cause, with the help of general practitioners, schools, social media, and social networks

Sulcus Vocalis and Benign Vocal Cord Lesions: Is There Any Relationship?

Background: Sulcus vocalis (SV) is a longitudinal groove in the free edge of the true vocal cord. It may impair phonation with incomplete glottic closure, phonasthenia and hoarseness. This study aims to detect a correlation between benign vocal cord lesions and the incidence of the SV. Methods: A retrospective study was carried out on patients who underwent transoral surgery due to benign vocal fold lesions and were selected according to strict criteria. Patients were divided into a group with sulcus vocalis (Group wSV) and a group without sulcus vocalis (Group w/oSV). The possible correlations between variables were assessed by the Pearson chi-square test (p &lt; 0.05). Results: The study included 232 vocal cord lesions in 229 patients: 62.88% were females whose mean age was 46.61 ± 14.04. The most frequent diseases were polyps (37.94%), nodules (18.53%) and Reinke's edema (21.12%). Statistically significant relationships were found between age and SV (p-value 0.0005) and between mild dysplasia and SV (p-value 0.03). Conclusions: This study did not detect a cause-effect relationship between SV and benign vocal fold lesions. SV within vocal fold lesions is more common in younger patients, suggesting a congenital nature of SV. In conclusion, in the case of a benign vocal fold lesion, a possible SV should be considered and researched to provide the patient the best healthcare

Positive Delphian node in laryngeal cancer: Predictive of thyroid gland metastasis?

Introduction: Laryngeal carcinoma represents the 22nd most common cancer worldwide. Thyroid metastasis from laryngeal cancer is extremely rare. Overall, thyroid gland involvement by metastatic carcinoma represents about 1.1-2.1 % among thyroid malignant diseases.Presentation of case: A male in his 70s came to our Otolaryngology Unit with a laryngeal squamous cell carcinoma (cT3). Total laryngectomy , bilateral neck dissection were performed. Histological examination revealed a pT3 carcinoma with sub-massive metastasis of the Delphian node. The patient underwent close follow-up. After eight months, neck examination revealed a suspected nodule in the right thyroid lobe. A right thyroid lobectomy was performed , histological assessment revealed a nodule with squamous carcinoma metastasis in the superior pole of the thyroid lobe. The remaining thyroid tissue was affected by multinodular macrofollicular goitre. The patient underwent adjuvant therapy. One year after the second surgery, he showed no signs of recurrence. Discussion: Thyroid gland metastasis from laryngeal carcinoma is a very rare occurrence. In literature, we found only three articles that describes thyroid metastasis in overall 7 patients affected by laryngeal squamous cell carcinoma. Positive Delphian lymph node is usually related to poor prognosis: in 2007 a study reported tumour recurrence in 15 out of 25 patients with metastatic Delphian lymph node within the first two years of surgery.Conclusion: Thyroid gland metastasis from laryngeal carcinoma is rare; so close follow-up of oncologic patients is mandatory and, most of all, the positive Delphian node should not be underestimated for its predictive value

NBI and Laryngeal Papillomatosis: A Diagnostic Challenge: A Systematic Review

Narrow-band imaging (NBI) represents a valid aid in laryngeal squamous cell carcinoma (LSCC) diagnosis for detecting vascular changes. However, LSCC and laryngeal papillomatosis (LP) show similar vascular patterns that may lead to misdiagnosis and improper treatment. This review aims to deepen this NBI limit in order to stress a careful preoperative evaluation of laryngeal lesions. The research was carried out on PubMed, Web of Science and Scopus databases using specific keywords. The topic of research was assessed by these parameters: accuracy, sensitivity, specificity, and positive and negative predictive values. This review included only five articles: they demonstrated that NBI is better than white-light endoscopy in detecting LSCC and LP. They also reported that LP is frequently mistaken for LSCC, resulting in high rates of false positives using NBI. This is the first review that emphasized this NBI limitation in distinguishing between LP and LSCC in cases of a type V pattern of intraepithelial papillary capillary loop. Although NBI application increased the rate of early cancer detection, LP reduces NBI accuracy. This drawback may lead to misdiagnosis and improper treatment. Our advice is to be careful in cases of type V pattern on NBI and to research LP epithelial and clinical features because it could be a pitfall

The immunohistochemical expression of leptin in lymph node metastasis from laryngeal squamous cell carcinoma (SCC)

Introduction: Leptin is a proteohormone produced predominantly by white adipocytes and primarily known for its key role in the control of food intake and sense of satiety. From its discover leptin has been found in different body districts, involved in always new functions and processes. In the last years numerous relationships between leptin and cancer has been found. The aim of this study is to test the leptin positivity in human primitive laryngeal squamous cell carcinoma (SCC) and in its lymph node metastasis. Materials and methods: Leptin positivity was detected by immunohistochemical analysis on pathological samples from 18 patients subjected to laryngectomy and neck dissection for SCC. Results: During the study we pointed out a statistically significant relationship (p &lt; 0.05) between leptin positivity levels and tumor differentiation grade, in particular we observed that a decrease in tumor leptin production correlates with higher level of cancer histological dedifferentiation. Conclusion: Our research on leptin expression in laryngeal squamous neoplastic pathology is aimed to the attempt of establishing a more precise patient risk stratification thanks to a new marker able to give a contribution to the identification of patient with poor prognosis and at risk of failure of actual standard therapy