Evidence for the production of Ar2∗−_2^{*-} metastable negative molecular ions in two-phase argon detectors for dark matter searches

The recent studies of electroluminescence (EL) properties in two-phase argon detectors for dark matter searches have revealed the presence of unusual delayed pulses in the EL signal in the form of two slow components with time constants of about 5 and 50 $\mu$s. These components were shown to be present in the charge signal itself, which clearly indicates that drifting electrons are temporarily trapped on two states of metastable negative argon ions which have never been observed before. In this work, using the pressure dependence of the ratio of slow component contributions measured in experiment, it is shown that these states are those of two types of metastable negative molecular ions, $\mathrm{Ar}_2^{*-}(b \ ^4\Sigma_u^-)$ and $\mathrm{Ar}_2^{*-}(a \ ^4\Sigma_g^+)$ for the higher and lower energy level respectively.Comment: 4 pages, 2 figure

New Indicators of Myocardial Work in Healthy Individuals

Aim. To study in healthy individuals the gender and age characteristics of left ventricular (LV) myocardial work indicators, their correlations with global LV deformity indicators and echocardiographic parameters characterizing LV systolic and diastolic functions.Materials and methods. 70 Healthy individuals (n=70; 34 men and 36 women; aged 39.3±8.9 years) were included in the study. The echocardiographic examination determined the standard parameters and indicators of myocardial work: global work efficiency (GWE), global constructive work (GCW), global wasted work (GWW), global myocardial work index (GWI); as well as the myocardium deformation characteristics: global longitudinal deformation (GLS), global radial deformation (GRS) and global circular deformation (GCS). Spearman's correlation coefficient was used to investigate the relationship between parameters. A correlation was considered weak at r≤0.3, moderate at 0.3<r<0.7, and strong at r≥0.7.Results. The average value of global work efficiency (GWE) in men was 97% (96; 98), in women – 98% (97; 98). Global constructive work (GCW) in men was 2343.8±350.4 mm Hg%, in women – 2362.2±343.8 mm Hg%. The average value of global wasted work (GWW) in men was 46 mm Hg% (27; 75), in women – 44 mm Hg% (33; 55.5). The global myocardial work index (GWI) in men was 2069.9±356.4 mm Hg%, in women – 2055.7±339.9 mm Hg%. No significant differences were found in the comparative analysis of performance indicators. The analysis of correlations found that the myocardial work indicators didn't have significant correlations with age. Ejection fraction was moderately correlated with GWI (r=0.45) and GCW (r=0.49). Global longitudinal strain was strongly correlated with GWI (r=0.77) and GCW (r=0.77). Global radial strain correlated moderately directly with GWI (r=0.4) and GCW (r=0.4). Global circular strain was moderately correlated with GCW (r=0.35). A strong negative correlation was found between the GWE indicator and the post systolic contraction index (PSI) (r=-0.85). At the same time, PSI and GWW had a strong positive correlation (r=0.85).Conclusion. Indicators of LV myocardial work in healthy individuals do not have gender differences. The efficiency of the work of the myocardium depends primarily on the deformation of the LV, while the constructive work is determined by the volume characteristics. The wasted work indicator depends on the number of segments that peak in the post-systolic period

Esophageal Hemorrhagic Syndromes

Esophageal  bleeding is  one of  the most  common medical emergencies. It takes  the  3rd place among  all digestive hemorrhages, and accounts for 14–16 % among all gastrointestinal bleeding. The most common cause of esophageal hemorrhages is Mallory – Weiss esophageal tear (10–12 %), less often – varicose veins of the esophagus in portal hypertension syndrome (up to 4 %) and, in some cases, is esophagitis of various etiologies (up to 1.6 %). The problem of  esophageal  bleeding  is  characterized  by  high  incidence,  high  mortality  rate  due  to  constant  increase  of  portal hyper tension cases, recurrences, difficulties in diagnosis, anatomical and physiological features of the esophagus, low efficiency of the main methods of hemostasis. There are various surgical and conservative methods of hemostasis, which show a variety of opinions in the solution to the problem of stopping esophageal bleeding. In Mallory – Weiss syndrome, endoscopic hemostasis is considered to be the preferred method of treatment. Management of portal hypertension is the most difficult task; a wide range of operations is used from the minimally invasive operations to the liver transplantation, as well as endoscopic hemostasis (ligation, sclerotherapy). In esophageal bleeding, due to reflux esophagitis, mainly conservative treatment is suggested, operations are performed with recurrences or complications. Each kind of esophageal hemorrhage is considered as a separate problem