Direct searches for cold dark matter in DarkSide-20k

The DarkSide scientific program concentrated on the dark matter search using low-radioactivity argon proposes the new generation DarkSide20k detector as a next step. For this purpose, the Global Argon Dark Matter Collaboration was formed by joining together main current argon-based experiments. The DarkSide-20k detector is designed as a 20 tons fiducial mass liquid argon Time Projection Chamber capable of identifying nuclear recoils from WIMP over the course of a very large exposure. It will be using custom-designed large area cryogenic silicon photo-multiplier’s arrays as a light detection system. Additionally, a huge effort to limit the radioactivity sources in construction materials and procedures is undertaken to fulfill the ‘background free’ operation goal. The construction is about to start in the INFN-LNGS underground laboratory in Italy. Due to its unique light emission properties and pulse shape discrimination abilities, liquid argon can provide excellent sensitivity for WIMP collisions and strong background suppression. The proposed experiment will reach the cross section versus mass range in the search for dark matter of 6.3 $\times$ 10$^{-48}$ cm$^{2}$ for the 90% C.L. exclusion significance for a 1 TeV / c$^{2}$ WIMP after a 200 t yr exposure. This will allow DarkSide-20k to discover, confirm, or exclude the WIMP dark matter hypothesis down the so-called neutrino floor barrier

Influence of obstructive sleep apnea on right heart structure and function

Introduction: Obstructive sleep apnea syndrome (OSAS) is a highly prevalent sleep disorder associated with increased cardiovascular morbidity and mortality. This study aimed to investigate heart structure and function and their correlation with the degree of OSAS and sleep indexes in patients diagnosed with OSAS. Materials and methods: A cohort of 77patients (48 males, aged 58.1 ± 11.0 years, body mass index [BMI] = 32.4 ± 6.2) admitted to the hospital due to suspected OSAS was examined using echocardiography and polysomnography. Results: Patients with moderate-to-severe OSAS compared to patients without diagnosed OSAS or with mild OSAS had greater right ventricular outflow tract (RVOT) dimensions (32.6 ± 3.6 vs 30.9 ± 2.4 mm; p < 0.05), larger right atrial area (RAA; 21.1 ± 4.8 vs 17.2 ± 3.2 mm; p = 0.002), greater right ventricular mid-cavity diameter (RVD; 35.5 ± 7.0 vs 32.2 ± 4.7 mm; p = 0.02), and diminished tricuspid annular plane systolic excursion (TAPSE, 21.9 ± 4.5 vs 25.8 ± 4.4 mm; p = 0.04), while there were no significant differences in tissue doppler imaging (TDI) parameters (S’ and E’) and in valvular regurgitation gradient for both groups. Moreover, significantly greater RVOT dimensions (31.6 ± 2.6 vs 30.9 ± 3.0 mm, p = 0.04), RVD (39.3 ± 7.0 vs 32.7 ± 5.2 mm, p = 0.003), and RAA (21.4 ± 4.4 vs 18.1 ± 4.2 mm, p = 0.02) as well as reduction in TAPSE (20.9 ± 5.3 vs 25.0 ± 4.3 mm, p = 0.01) were observed in patients having ≥ 10 episodes of obstructive apnea (OA) per hour. Conclusions: In moderate-to-severe OSAS patients, right ventricular (RV) enlargement was observed together with RV dysfunction as measured by TAPSE. Examination using TDI is not superior to standard echocardiography for the detection of heart pathology in OSAS patients. Right heart pathology is present predominantly in patients with obstructive apnea

Lead shielding efficiency from the gamma background measurements in the salt cavern of the Polkowice–Sieroszowice copper mine

The studies of lead shielding efficiency from the gamma background measurements were performed in the salt cavern of the copper mine - a site considered for an underground laboratory. Within the energy range of 50–2700 keV, the measured gamma-ray count rates normalized to the mass of the high-purity detectors germanium crystal are 5.93 and 6.32 s−1kg−1 for the used low-background and portable spectrometers, respectively. The gamma-ray flux of 0.124 (2) cm−2s−1 connected with the natural radioisotopes was observed by the portable HPGe, including 0.026 (1) cm−2s−1 contribution of radon decay products, whereas the photon flux at the spectrum continuum was 0.18 (5) cm−2s−1

Purification of large volume of liquid argon for LEGEND-200

The design, construction and performance of the system capable of purifying 65m$^{3}$ of liquid argon to sub-ppm level designed for LEGEND–200 experiment is presented. The quality of the purified liquid argon is monitored in real-time during the purification process, by measuring the argon triplet state lifetime and simultaneous direct measurements of the concentrations of impurities such as water, oxygen, and nitrogen with a sensitivity of 0.1 ppm. The achieved argon triplet lifetime value measured inside the LEGEND cryostat, when filled in 70% of its capacity, was at the level of $\tau_{3}$ = 1.3 μs. If needed, the system may also be used later to purify liquid argon already filled into the LEGEND cryostat in the loop mode

Influence of obstructive sleep apnea on right heart structure and function

Introduction: Obstructive sleep apnea syndrome (OSAS) is a highly prevalent sleep disorder associated with increased cardiovascular morbidity and mortality. This study aimed to investigate heart structure and function and their correlation with the degree of OSAS and sleep indexes in patients diagnosed with OSAS. Materials and methods: A cohort of 77patients (48 males, aged 58.1 ± 11.0 years, body mass index [BMI] = 32.4 ± 6.2) admitted to the hospital due to suspected OSAS was examined using echocardiography and polysomnography. Results: Patients with moderate-to-severe OSAS compared to patients without diagnosed OSAS or with mild OSAS had greater right ventricular outflow tract (RVOT) dimensions (32.6 ± 3.6 vs. 30.9 ± 2.4 mm; p < 0.05), larger right atrial area (RAA; 21.1 ± 4.8 vs. 17.2 ± 3.2 mm; p = 0.002), greater right ventricular mid-cavity diameter (RVD; 35.5 ± 7.0 vs. 32.2 ± 4.7 mm; p = 0.02), and diminished tricuspid annular plane systolic excursion (TAPSE, 21.9 ± 4.5 vs. 25.8 ± 4.4 mm; p = 0.04), while there were no significant differences in tissue doppler imaging (TDI) parameters (S’ and E’) and in valvular regurgitation gradient for both groups. Moreover, significantly greater RVOT dimensions (31.6 ± 2.6 vs. 30.9 ± 3.0 mm, p = 0.04), RVD (39.3 ± 7.0 vs. 32.7 ± 5.2 mm, p = 0.003), and RAA (21.4 ± 4.4 vs. 18.1 ± 4.2 mm, p = 0.02) as well as reduction in TAPSE (20.9 ± 5.3 vs. 25.0 ± 4.3 mm, p = 0.01) were observed in patients having ≥ 10 episodes of obstructive apnea (OA) per hour. Conclusions: In moderate-to-severe OSAS patients, right ventricular (RV) enlargement was observed together with RV dysfunction as measured by TAPSE. Examination using TDI is not superior to standard echocardiography for the detection of heart pathology in OSAS patients. Right heart pathology is present predominantly in patients with obstructive apnea

Endothelial dysfunction in obstructive sleep apnea patients

PURPOSE: Obstructive sleep apnea syndrome (OSAS) is an independent risk factor for cardiovascular diseases. The aim of the study was to assess the influence of OSAS on endothelial dysfunction and thrombosis biomarkers and to evaluate the effect of treatment with continuous positive airway pressure (CPAP) on biomarker levels. METHODS: NT-proBNP, sICAM-1, endothelin-1, von Willebrand factor, D-dimers, and thrombin-antithrombin complex (TAT) were measured in 50 patients diagnosed with moderate-to-severe OSAS. All patients underwent transthoracic echocardiography, and 38 months after the inclusion, 16 CPAP users and 22 non-CPAP users were reassessed. RESULTS: Sleep-related indices of apnea-hypopnea index (AHI) and mean SpO(2) were associated with higher sICAM-1 levels (AHI  37 mm: 1.96 ± 1.20 ng/ml, p = 0.04). Endothelin-1 levels were higher in patients with decreased right ventricular function (right ventricle TDI-derived S′ ≥ 12 cm/s: 11.5 ± 10.9 vs. < 12 cm/s: 26.0 ± 13.2 pg/ml, p = 0.04). An increase in NT-proBNP was related to impaired parameters of the right ventricular contractile function. There were no correlations between long-term CPAP therapy and the levels of biomarkers. CONCLUSION: Severe OSAS influences endothelial damage as manifested by an increase in sICAM-1 levels. Changes in right ventricular structure and function, observed mainly in patients with higher TAT and endothelin-1 levels, are also manifested by an increase in NT-proBNP levels. Long-term CPAP treatment does not seem to influence biomarkers in patients with moderate-to-severe OSAS, which may help to explain the lack of influence of CPAP on cardiovascular risk reduction

Maturation process of photosynthetic membranes observed by proton magnetic relaxation and sorption isotherm

Mild rehydration from the gaseous phase of the developing and mature lyophilized wheat photosynthetic membranes was investigated using hydration kinetics, adsorption isotherm and high power proton relaxometry. Hydration time courses are single exponential for all target air humidities; the hydration time $t^h$ equals to (11.9±3.6) h for the mature membranes, and (17.0±3.2) h for the developing membranes. The sorption isotherm is sigmoidal in form and well fitted using the Dent model; the mass of water saturating primary binding sites equals Δ M/$m_0$= 0.033±0.013 and 0.025±0.007 for the mature and for the developing membranes, respectively, where $m_0$ is the dry mass of the sample, and Δ M is mass of water taken up. Proton free induction decays distinguish: (i) an immobilized proton (Gaussian) component, $S_0$, originating from protons of solid matrix of lyophilizate; (ii) a Gaussian component, $S_1$, from water bound to the primary water binding sites and localized in proximity of paramagnetic ions; (iii) an exponentially decaying contribution, $L_1$, from water tightly bound to lyophilizate surface; and (iv) exponentially decaying loosely bound water pool, $L_2$. A significant contribution of water "sealed" in the structure of lyophilized membrane (from the fraction $S_1$ and $L_1$) is detected. The mass of "sealed" water fraction is Δ $M_{S}//m_0$ = 0.047±0.023 and 0.072±0.021 for the mature and for the developing membranes, respectively

Maturation Process of Photosynthetic Membranes Observed by Proton Magnetic Relaxation and Sorption Isotherm

Mild rehydration from the gaseous phase of the developing and mature lyophilized wheat photosynthetic membranes was investigated using hydration kinetics, adsorption isotherm and high power proton relaxometry. Hydration time courses are single exponential for all target air humidities; the hydration time $t^h$ equals to (11.9±3.6) h for the mature membranes, and (17.0±3.2) h for the developing membranes. The sorption isotherm is sigmoidal in form and well fitted using the Dent model; the mass of water saturating primary binding sites equals Δ M/$m_0$= 0.033±0.013 and 0.025±0.007 for the mature and for the developing membranes, respectively, where $m_0$ is the dry mass of the sample, and Δ M is mass of water taken up. Proton free induction decays distinguish: (i) an immobilized proton (Gaussian) component, $S_0$, originating from protons of solid matrix of lyophilizate; (ii) a Gaussian component, $S_1$, from water bound to the primary water binding sites and localized in proximity of paramagnetic ions; (iii) an exponentially decaying contribution, $L_1$, from water tightly bound to lyophilizate surface; and (iv) exponentially decaying loosely bound water pool, $L_2$. A significant contribution of water "sealed" in the structure of lyophilized membrane (from the fraction $S_1$ and $L_1$) is detected. The mass of "sealed" water fraction is Δ $M_{S}//m_0$ = 0.047±0.023 and 0.072±0.021 for the mature and for the developing membranes, respectively