A metallicity study of 1987A-like supernova host galaxies

The origin of the blue supergiant (BSG) progenitor of Supernova (SN) 1987A has long been debated, along with the role that its sub-solar metallicity played. We now have a sample of 1987A-like SNe that arise from the core collapse (CC) of BSGs. The metallicity of the explosion sites of the known BSG SNe is investigated, as well as their association to star-forming regions. Both indirect and direct metallicity measurements of 13 BSG SN host galaxies are presented, and compared to those of other CC SN types. Indirect measurements are based on the known luminosity-metallicity relation and on published metallicity gradients of spiral galaxies. To provide direct estimates based on strong line diagnostics, we obtained spectra of each BSG SN host both at the SN explosion site and at the positions of other HII regions. Continuum-subtracted Ha images allowed us to quantify the association between BSG SNe and star-forming regions. BSG SNe explode either in low-luminosity galaxies or at large distances from the nuclei of luminous hosts. Therefore, their indirectly measured metallicities are typically lower than those of SNe IIP and Ibc. This is confirmed by the direct estimates, which show slightly sub-solar values (12+log(O/H)=8.3-8.4 dex), similar to that of the Large Magellanic Cloud (LMC), where SN 1987A exploded. However, two SNe (1998A and 2004em) were found at near solar metallicity. SNe IIb have a metallicity distribution similar to that of BSG SNe. Finally, the association to star-forming regions is similar among BSG SNe, SNe IIP and IIn. Our results suggest that LMC metal abundances play a role in the formation of some 1987A-like SNe. This would naturally fit in a single star scenario for the progenitors. However, the existence of two events at nearly solar metallicity suggests that also other channels, e.g. binarity, contribute to produce BSG SNe.Comment: 28 pages, 17 figures; accepted for publication (Astronomy and Astrophysics); abstract abridged for arXiv submissio

The correlation of the severity of duodenum injuries and the mechanism of trauma in polytraumatism

Scopul lucrării. Politraumatismul constituie circa 15-20% din totalul leziunilor traumatice cu o mortalitate de 26-50% ,din cauza leziunilor grave în două sau mai multe regiuni sau organe cu risc vital major, fiind în strânsă și directă legătură cu mecanismul traumei. Scopul este analiza severității lezionale ale duodenului în raport cu mecanismul traumei. Materiale și metode. Studiul este bazat pe analiza a 44 pacienți tratați cu leziuni de duoden în perioada anilor 1999 - 2018. B-39, F-5, vârsta 18-70 ani. Mecanismul traumei: accident rutier 13 (29,54%), corpi străini 2(4,54%), sport 2(4,54%), catatrauma 7(15,9%), agresiune fizică 8(18,18%), strivire 1(2,27%), armă albă 7(15.9%), armă de foc 5(11,36), explozie 1(2,27%).Toți pacienții au fost supuși actului chirurgical după indicații. Volumul și metoda de corecție s-a stabilit individual în raport cu condițiile intraoperatoriipneumoperitoneum, peritonită, hematom sau flegmon retroperitoneal. Rezultate. Intraoperator a fost stabilit gradul de severitate a leziunilor duodenale și a celor asociate.Lezarea duodenului de gradul I-II a fost stabilita în 30(68%), decedați 13(29%), gradul III-IV 14(31%), decedați 9(20%). După mecanismul traumei au predominat accidentele rutiere, agresiunea fizică urmată de catatraumă și armă albă. Concluzii. Analiza corelației severității lezionale și mecanismul traumei nu relevă o diferență semnificativă în lotul de studiu.Mortalitatea a fost indusă de anemie severă, septicemie.Aim of study. Polytrauma constitutes about 15-20% of all traumatic injuries with a mortality of 26-50%, due to serious injuries in two or more regions or organs with major vital risk, being in close and direct connection with the trauma mechanism. The goal is analysis of duodenal lesion severity in relation to trauma mechanism. Materials and methods. The study is based on the analysis of 44 patients treated with duodenal lesions between 1999 and 2018. M -39, W-5, age 18-70 years. Trauma mechanism: Road accident – 13 (29.54%), foreign bodies 2(4.54%), sports 2(4.54%), catatrauma 7(15.9%), physical aggression 8(18.18%) ), crushing 1(2.27%), white weapon 7(15.9%), firearm 5(11.36), explosion 1(2.27%). All patients underwent surgery as indicated. The volume and method of correction was established individually in relation to the intraoperative conditions - pneumoperitoneum, peritonitis, hematoma or retroperitoneal phlegmon. Results. Intraoperatively, the degree of severity of the duodenal and associated injuries was established. Grade I-II duodenal injury was established in 30(68%), 13(29%) died, III-IV grade 14(31%), died 9(20%). After the mechanism of trauma, traffic accidents prevailed, physical aggression followed by catatrauma and white weapons. Conclusions. Correlation analysis of lesion severity and trauma mechanism does not reveal a significant difference in the study group. Mortality was induced by severe anemia, septicemia

The high-redshift gamma-ray burst GRB140515A

High-redshift gamma-ray bursts have several advantages for the study of the distant universe, providing unique information about the structure and properties of the galaxies in which they exploded. Spectroscopic identification with large ground-based telescopes has improved our knowledge of the class of such distant events. We present the multi-wavelength analysis of the high-$z$ Swift gamma-ray burst GRB140515A ($z = 6.327$). The best estimate of the neutral hydrogen fraction of the intergalactic medium (IGM) towards the burst is $x_{HI} \leq 0.002$. The spectral absorption lines detected for this event are the weakest lines ever observed in gamma-ray burst afterglows, suggesting that GRB140515A exploded in a very low density environment. Its circum-burst medium is characterised by an average extinction (A$_{\rm V} \sim 0.1$) that seems to be typical of $z \ge 6$ events. The observed multi-band light curves are explained either with a very flat injected spectrum ($p = 1.7$) or with a multi-component emission ($p = 2.1$). In the second case a long-lasting central engine activity is needed in order to explain the late time X-ray emission. The possible origin of GRB140515A from a Pop III (or from a Pop II stars with local environment enriched by Pop III) massive star is unlikely.Comment: 10 pages, 8 figures, 5 tables, submitted to Astronomy & Astrophysic

Абдоминосакральная резекция в хирургическом лечении рака прямой кишки

Surgery is the only potentially radical treatment option for locally advanced and recurrent rectal tumors invading the sacral vertebrae. However, the choice of tactics for this patient category remains a difficult task. In spite of the fact that chemoradiation therapy yields good results, it is very difficult to differentiate postradiation changes and residual tumor; the immediate results of combined surgical interventions accompanied by sacral resection remain unsatisfactory, which restricts their use in routine practice and the frequency of unradical operations and local recurrences remains high. Optimization of the results of abdominosacral resection in patients with rectal cancer requires that the definite principles should be adhered to. The chief task of treatment (radical surgery) is fulfilled via resection of the sacrum and, if indicated, other organs even to the extent of performing total pelvic evisceration. In the present view, radiotherapy is a compulsory component of combined treatment that enhances surgical radicalism. However, its impact on the results of this intervention type has been inadequately studied so far. Careful selection of patients to undergo abdominosacral resection determines high requirements for preoperative tumor imaging techniques. Due to their technical complicacy, it is recommended that this operation should be made only by specialized cancer centers having capacities for performing combined treatment for colorectal cancer. Единственным потенциально радикальным методом лечения местно-распространенных и рецидивных опухолей прямой кишки, инвазирующих в крестцовые позвонки, является хирургический. Однако выбор лечебной тактики в отношении данной категории больных остается трудной задачей. Несмотря на то, что химиолучевая терапия приносит хорошие результаты, дифференцировать постлучевые изменения и резидуальную опухоль чрезвычайно сложно; непосредственные результаты комбинированных хирургических вмешательств, сопровождающихся резекцией крестца, остаются неудовлетворительными, что ограничивает их применение в рутинной практике, а количество нерадикальных операций и частота развития местных рецидивов по-прежнему высоки. Оптимизация результатов абдоминосакральной резекции (АСР) у больных раком прямой кишки требует соблюдения определенных принципов. Главная задача лечения – выполнение радикальной операции – решается путем резекции крестца, а также (по показаниям) других органов, вплоть до тотальной эвисцерации таза. Согласно современным представлениям, лучевая терапия является обязательным компонентом комбинированного лечения, повышающим радикализм операции. Однако ее влияние на результаты АСР пока недостаточно изучено. Тщательный отбор пациентов, подлежащих хирургическому вмешательству, обусловливает высокие требования к методам предоперационной визуализации опухоли. В связи с технической сложностью выполнять данную операцию рекомендуется только в специализированных онкологических центрах, располагающих возможностями комбинированного лечения колоректального рака.

ВЛИЯНИЕ ЗАДЕРЖКИ ДИАГНОСТИКИ НА ДОГОСПИТАЛЬНОМ ЭТАПЕ НА РЕЗУЛЬТАТЫ ЛЕЧЕНИЯ БОЛЬНЫХ С ГЕРМИНОГЕННЫМИ ОПУХОЛЯМИ ЯИЧКА В САНКТ-ПЕТЕРБУРГЕ

Over the past quarter-century germ cell tumors are one of the few cancers for which highly effective treatment is found. However there is a lack of awareness of young men and general practitioners about germ cell tumors which is often cause of late medical aid appealability and potential diagnostic errors. Reducing the time between patient's medical aid appealability and final diagnosis may contribute to the diagnostics of germ cell tumors in the early stages, reducing the amount of treatment and improving survival rates.За последние четверть века герминогенные опухоли (ГО) стали одним из немногих онкологических заболеваний, при которых возможно высокоэффективное лечение. Однако сохраняется недостаточная осведомленность молодых мужчин и врачей общей практики о герминогенных опухолях, что часто является причиной поздней обращаемости и возможных диагностических ошибок. Сокращение времени от обращения пациента до окончательной постановки диагноза может способствовать диагностике ГО яичка на ранних стадиях, уменьшению объема необходимых лечебных мероприятий и улучшению показателей выживаемости больных

ИЗУЧЕНИЕ МЕХАНИЗМОВ ФОТОИНДУЦИРОВАННОЙ ГИБЕЛИ НА МОДЕЛИ КЛЕТОК МЕЛАНОМЫ КОЖИ

The results of the experimental study of immune response of human skin malignant melanoma cells Mel 226 on photodynamic exposure are represented in the article. Photoinduced apoptosis of skin malignant melanoma was studied in vitro. The study showed that irradiation with the agent fotoditazin at dose of 0.5–2.5 µg/ml (6 and 10 min exposure 30 min before irradiation; irradiation parameters: wavelength of 662 nm, total light dose from 40 to 60 J/cm2) induced early apoptosis. The increase of the time of laser irradiation significantly accelerates the conversion of photosensitized tumor cells from early to late apoptosis.В статье представлены результаты экспериментального исследования иммунного ответа клеток меланомы кожи человека Mel 226 на фотодинамическое воздействие. Изучен фотоиндуцированный апоптоз клеток меланомы кожи in vitro. Исследования показали, что облучение с препаратом фотодитазин в концентрациях 0,5-2,5 мкг/мл (экспозиция в течение 6 и 10 мин за 30 мин до облучения; параметры облучения: длина волны 662 нм, суммарная доза облучения от 40 до 60 Дж/см2) индуцирует ранний апоптоз. Увеличение времени лазерного облучения достоверно ускоряет переход фотосенсибилизированных опухолевых клеток из ранней фазы апоп-тоза в позднюю

Primary Black Hole Spin in OJ 287 as Determined by the General Relativity Centenary Flare

OJ 287 is a quasi-periodic quasar with roughly 12 year optical cycles. It displays prominent outbursts that are predictable in a binary black hole model. The model predicted a major optical outburst in 2015 December. We found that the outburst did occur within the expected time range, peaking on 2015 December 5 at magnitude 12.9 in the optical R -band. Based on Swift /XRT satellite measurements and optical polarization data, we find that it included a major thermal component. Its timing provides an accurate estimate for the spin of the primary black hole, ##IMG## [http://ej.iop.org/images/2041-8205/819/2/L37/apjl523055ieqn1.gif] $i =0.313pm 0.01$ . The present outburst also confirms the established general relativistic properties of the system such as the loss of orbital energy to gravitational radiation at the 2% accuracy level, and it opens up the possibility of testing the black hole no-hair theorem with 10% accuracy during the present decade.Peer reviewe