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•The Sr1−3xBi2xФxMoO4 (0.025 ≤ x ≤ 0.15) showed a tetragonal defect scheelite structure.•The Sr1−3xBi2xФxMoO4 (0.15 < x ≤ 0.225) showed a supercell with asup ≈ √5a, csup ≈ c.•Raman ...spectroscopy showed a strong distortion of MoO4 polyhedra.•Calculated and experimental values of energy gap of Sr1−3xBi2xФxMoO4 decreased with x.•The conductivity of Sr1−3xBi2xФxMoO4 increases x.
The electronic and crystal structures of the Sr1−3xBi2xФxMoO4 series (0.025 ≤ x ≤ 0.30, where Ф represents cation vacancies) were studied. The 0.025 ≤ x ≤ 0.15 compositions showed a defect scheelite structure. Powder X-ray and neutron diffraction patterns for compositions with 0.15 < x ≤ 0.225 exhibited a tetragonal supercell with asup ≈ √5a, csup ≈ c where a and c are the tetragonal scheelite cell parameters. Strong distortion of MoO4 polyhedra was shown by Raman spectroscopy and described by the calculated phonon spectra of “virtual crystals” of Bi2+MoO4 and Ф2+MoO4. The electronic structures were calculated for both types of structure. The decrease of the calculated energy gap is consistent with experimental data from Kubelka-Munk measurements. The electroconductive properties were measured by A.C. impedance spectroscopy. For Sr1−3xBi2xФxMoO4 compositions conductivity increases with increasing x-value, with maximum values of conductivity at 948 K of 2.82 × 10−5S cm−1 for the x = 0.20 composition.
The study provides novel insights into the crystal–chemical and optical characteristics of frankamenite. Frankamenite belongs to a special group (canasite group) of the complex alkaline Ca-(K)-(Na) ...silicates, and it was found in charoitites from the only known location, Murun Massif, Eastern Siberia, Russia. The crystal–chemical, vibrational, and optical properties of frankamenite were investigated by combining electron probe microanalysis (EPMA), single-crystal X-ray diffraction (SCXRD), infrared (IR) absorption, Raman, UV-Visible absorption, and electron spin resonance (ESR) spectroscopy. The behavior of the peaks in the IR spectra was also studied using ab initio calculations. Detailed characteristics of the internal composition and structure of the mineral species were described, and vibrational and optical properties based on these peculiarities were interpreted. The thermally stimulated reorientation of the H2O molecules and OH− groups was studied by thermo-Raman spectroscopy. Octahedral cationic positions can be readily doped with transition metal and lanthanide ions that provide a promising opportunity to adjust the Ce3+ luminescence. Hence, frankamenite is a potential material for ion exchange, novel phosphors, and luminophores.
Introduction: Fluid overload plays an important role in the development of pulmonary edema in critically ill patients. ...the goal-directed fluid management serves as a key component in the therapy ...of acute respiratory distress syndrome (ARDS). The aim of our study was to compare the dehydration therapy (DT) in ARDS guided by global end-diastolic volume index (GEDVI) and extravascular lung water index (EVLWI).
Protective perioperative ventilation has been shown to improve outcomes and reduce the incidence of postoperative pulmonary complications. The goal of this study was to assess the effects of ...ventilation with low tidal volume (V
) either alone or in a combination with moderate permissive hypercapnia in major pancreatoduodenal interventions.
Sixty adult patients scheduled for elective pancreatoduodenal surgery with duration >2 h were enrolled into a prospective single-center study. All patients were randomized to three groups receiving high V
10 mL/kg of predicted body weight (PBW), the HVT group,
= 20, low V
(6 mL/kg PBW, the LVT group,
= 20), and low V
combined with a moderate hypercapnia and hypercapnic acidosis (6 mL/kg PBW, PaCO
45-60 mm Hg, the LVT + HC group,
= 20). Cardiopulmonary parameters and the incidence of complications were registered during surgery and postoperatively.
The values of V
were 610 (563-712), 370 (321-400), and 340 (312-430) mL/kg for the HVT, the LVT, and the LVT + HC groups, respectively (
< 0.001). Compared to the HVT group, PaO
/FiO
ratio was increased in the LVT group by 15%: 333 (301-381) vs. 382 (349-423) mm Hg at 24 h postoperatively (
< 0.05). The HVT group had significantly higher incidence of atelectases (
= 6), despite lower incidence of smoking compared with the LVT (
= 1) group (
= 0.017) and demonstrated longer length of hospital stay. The patients of the LVT + HC group had lower arterial lactate and bicarbonate excess values by the end of surgery.
In major pancreatoduodenal interventions, preventively protective V
improves postoperative oxygenation, reduces the incidence of atelectases, and shortens length of hospital stay. The combination of low V
and permissive hypercapnia results in hypercapnic acidosis decreasing the lactate concentration but adding no additional benefits and warrants further investigations.
Advanced mathematical and static methods of processing of the results of experimental studies, comparison of the obtained data with the works of authors investigating traffic safety, analysis, ...reconstruction and investigation of road traffic accidents, as well as expert analysis helped to identify the most relevant parameters of the vehicle condition and the road environment necessary for automobile technical expert evaluation (e.g. the friction coefficient, vehicle braking performance under different loads on all categories of roads with different types of road surface, roughness, wheel tracking, hydraulic roughness) and to obtain their actual values that are important for expert studies; and that was proved by experiments. The developed method of reconstruction and investigation of accidents implies calculation of state parameters of the vehicle and the road environment on the basis of the type of the investigated accident and geometric characteristics of the accident place.
Presently used conventional Russian pavements including macadam base asphalt covering loses its advantages under the current conditions of heavy and high traffic. In this regard, for the development ...of the country's economy and transport infrastructure, a rational pavement design is developed, which is presented in rigid fragmented asphalt bedding course. It provides high homogeneity and uniform strength of coating with low variation factors resulting in increase of the pavement life time and service life. The rational pavement design with a fragmented base layer compared to the conventional one has a higher resistance to formation of ruts and cracks that improves safety and reduces the risk of an accident.
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