Pneumomediastinum as a predictor of negative prognosis in patients with coronavirus pneumonia

Aim of the study was to analyze the course of coronavirus pneumonia in patients with pneumomediastinum. Material and methods. The study included 139 patients, 71 of whom developed spontaneous pneumomediastinum against the background of coronavirus pneumonia. Laboratory, clinical and radiological data were analyzed and compared. Results. The relationship between the severity of viral pneumonia (3rd–4th degree of severity according to MSCT) and pneumomediastinum was revealed. It was found that spontaneous mediastinal emphysema in patients with COVID-19 signifcantly more often leads to the development of acute respiratory distress syndrome, multiple organ failure and can be a predictor of negative prognosis of the disease outcome. Conclusions. Pneumomediastinum in patients with viral pneumonia caused by a new coronavirus infection is a predictor of severe disease and poor prognosis. With an increase in spontaneous mediastinal emphysema without pneumothorax, it is recommended to perform mediastinotomy according to Razumovsky’s indications, and in case of clinically signifcant concomitant pneumothorax – drainage and revision of the mediastinum

Results from the Soviet-American gallium experiment

A radiochemical 71Ga-71Ge experiment to determine the primary flux of neutrinos from the Sun began measurements of the solar neutrino flux at the Baksan Neutrino Observatory in 1990. The number of 71Ge atoms extracted from 30 tons of gallium in 1990 and 57 tons in 1991 was measured in twelve runs during the period of January 1990 to December 1991. For the 1990 data, we observed the capture rate to be 20 + 15 -20 (stat) ± 32 (syst) SNU, resulting in a limit of less than 79 SNU (90% CL). This is to be compared with 132 SNU predicted by the Standard Solar Model. The 1991 data, taken with 57 tons of gallium, shows a non zero 71Ge signal. A final result from the 1990 and 1991 data is still pending completion of studies of possible systematic effects. © 1993

Preliminary results from the Russian-American Gallium Experiment Cr-neutrino source measurement

The Russian-American Gallium Experiment has been collecting solar neutrino data since early 1990. The flux measurement of solar neutrinos is well below that expected from solar models. We discuss the initial results of a measurement of experimental efficiencies by exposing the gallium target to neutrinos from an artificial source. The capture rate of neutrinos from this source is very close to that which is expected. The result can be expressed as a ratio of the measured capture rate to the anticipated rate from the source activity. This ratio is 0.93 + 0.15, - 0.17 where the systematic and statistical errors have been combined. To first order the experimental efficiencies are in agreement with those determined during solar neutrino measurements and in previous auxiliary measurements. One must conclude that the discrepancy between the measured solar neutrino flux and that predicted by the solar models can not arise from an experimental artifact

First results from the Soviet-American gallium experiment

The Soviet-American Gallium Experiment is the first experiment able to measure the dominant flux of low energy p-p solar neutrinos. Four extractions made during January to May 1990 from 30 tons of gallium have been counted and indicate that the flux is consistent with 0 SNU and is less than 72 SNU (68% CL) and less than 138 SNU (95% CL). This is to be compared with the flux of 132 SNU predicted by the Standard Solar Model. © 1991

The Baksan gallium solar neutrino experiment

A radiochemical 71Ga-71Ge experiment to determine the integral flux of neutrinos from the sun has been constructed at the Baksan Neutrino Observatory in the USSR. Measurements have begun with 30 tonnes of gallium. An additional 30 tonnes of gallium are being installed so as to perform the full experiment with a 60-tonne target. The motivation, experiment procedures, and present status of this experiment are described. © 1990

Measuring the 14C content in liquid scintillators

We are going to perform a series of measurements where the 14C/12C ratio will be measured from several liquid scintillator samples with a dedicated setup. The setup is designed with the aim of measuring ratios smaller than 10−18. Measurements take place in two underground laboratories: in the Baksan Neutrino Observatory, Russia and in the Pyh¨asalmi mine, Finland. In Baksan the measurements started in 2015 and in Pyh¨asalmi they start in the beginning of 2015. In order to fully understand the operation of the setup and its background contributions a development of simulation packages has also been started. Low-energy neutrino detection with a liquid scintillator requires that the intrinsic 14C content in the liquid is extremely low. In the Borexino CTF detector at Gran Sasso, Italy the 14C/12C ratio of 2 × 10−18 has been achieved being the lowest 14C concentration ever measured. In principle, the older the oil or gas source that the liquid scintillator is derived of and the deeper it situates, the smaller the 14C/12C ratio is supposed to be. This, however, is not generally the case, and the ratio is probably determined by the U and Th content of the local environment.peerReviewe

Towards 14C-free liquid scintillator

A series of measurements has been started where the 14C concentration is determined from several liquid scintillator samples. A dedicated setup has been designed and constructed with the aim of measuring concentrations smaller than 10−18. Measurements take place in two underground laboratories: in the Baksan Neutrino Observatory, Russia, and in the new Callio Lab in the Pyhäsalmi mine, Finland. Low-energy neutrino detection with a liquid scintillator requires that the intrinsic 14C concentration in the liquid is extremely low. In the Borexino CTF detector the concentration of 2 × 10−18 has been achieved being the lowest value ever measured. In principle, the older the oil or gas source that the liquid scintillator is derived from and the deeper it situates, the smaller the 14C concentration is supposed to be. This, however, is not generally the case and the concentration is probably due to the U and Th content of the local environment.peerReviewe

Towards ¹⁴C-free liquid scintillator

Abstract A series of measurements has been started where the ¹⁴C concentration is determined from several liquid scintillator samples. A dedicated setup has been designed and constructed with the aim of measuring concentrations smaller than 10−18. Measurements take place in two underground laboratories: in the Baksan Neutrino Observatory, Russia, and in the new Callio Lab in the Pyhäsalmi mine, Finland. Low-energy neutrino detection with a liquid scintillator requires that the intrinsic ¹⁴C concentration in the liquid is extremely low. In the Borexino CTF detector the concentration of 2 × 10−18 has been achieved being the lowest value ever measured. In principle, the older the oil or gas source that the liquid scintillator is derived from and the deeper it situates, the smaller the ¹⁴C concentration is supposed to be. This, however, is not generally the case and the concentration is probably due to the U and Th content of the local environment

Concentration of ¹⁴C in liquid scintillator

Abstract The main background hindering low-energy (≲ 200 keV) neutrino measurements with liquid scintillators comes from the minute remanence of the cosmogenic ¹⁴C (T₁/₂ ≃ 5700 a) present in the organic oil constituting the bulk of the scintillator. The β-decay endpoint energy of ¹⁴C is quite low, Q = 156 keV, and the counting rate from ¹⁴C is often reduced by threshold settings. However, too high concentration of ¹⁴C may results in pile-up pulses. For example, in the Borexino detector at Gran Sasso, Italy, being the most sensitive neutrino detector, the trigger rate is largely dominated by the ¹⁴C isotope [1] with the concentration of 2 × 10⁻¹⁸ [2] It is the lowest ¹⁴C concentration value ever measured. There are only a few results available on the ¹⁴C concentration. In addition to the one in Ref. [2] there are three other measurements reported in Refs. [3, 4, 5]. Obviously ¹⁴C cannot be removed from liquid scintillators by chemical methods, or by other methods in large quantities (liters). In principle, the older is the oil or gas source that the liquid scintillator is made of and the deeper it situates, the smaller the ¹⁴C concentration should be. This, however, is not generally the case and it is believed that the ratio depends on the activity (U and Th content) in the environment of the source. We are performing a series of measurements where the ¹⁴C concentration will be measured from several liquid scintillator samples. They need low-background environment and are taking place in two deep underground laboratories: in the new CallioLab laboratory in the Pyhäsalmi mine, Finland, and at the Baksan Neutrino Observatory, Russia, in order to reduce and better understand the systematical uncertainties. Preliminary results will be presented