The purpose of the research is to increase the efficiency of underground mining of flat coal-bearing seams with powered longwalls in the areas characterized by complex hypsometry and high water ...inflows. The modern global trend to increase the size of extraction panel (the length of longwall and the length of column) during the development of flat coal-bearing seams is shown. The results of the development of a three-dimensional model of the array are presented, which allows building profiles of the earth surface and the developed seams in the areas with complex hypsometry. The applicability of the use of such models to determine the rational place for the formation of dismantling chamber is shown. The interrelation between the length of longwall and the length of extraction panel during the mining thick coal-bearing seams is shown. The assessment of the additional costs and damages caused by the division of the extraction panels into two parts is carried out to ensure an upward order of mining reserves under the conditions of increased water inflows. The field of rational application of the division of extraction panel into two parts for the conditions of the mine site named after V.D.Yalevsky is determined.
The paper presents results of 3-D numerical modeling by a finite element method of the stress condition of the rock massif when undermining the flat thick coal seam. As a result of the executed ...research, the authors establish influences of the pillars left between longwall panels in previously mined top seam 70 on distribution of stress in the current mining seam 69. The need for application of 3-D numerical models to take a note of imposing the bearing pressure of a longwall and the increased stress from the pillar is shown. Recommendations on the location of entries of the longwall panel when undermining the coal seam are made.
The paper presents results of numerical modeling of the longwall gateroad floor heave in the Taldinskaya-Zapadnaya-2 mine. The research is conducted using the finite element method. The research has ...shown that the floor heave can be reduced when using the relieve slots which are cut in two areas. The reasons and the mechanism of a floor heave of entries are considered. Influence of the major geological and mining factors is revealed. Recommendations about decrease in heave in entries of coal mines are made.
This study aims to evaluate the left ventricle (LV) systolic and diastolic function in patients with idiopathic pulmonary arterial hypertension (IPAH) and its correlation with systemic arterial ...stiffness assessed by cardio-ankle vascular index (CAVI).
We included 37 patients with IPAH and 20 healthy people matched by age. All patients were assessed: vital signs, 6-minute walk test, NT-proBNP level, the CAVI, the right ventricular (RV) and LV function parameters, including ejection time (ET), tissue speckle-tracking values - global longitudinal strain (GLS) and strain rate (SR).
The groups were matched by age, gender, BMI, office SBP and DBP. Patients with IPAH had higher heart rate, NT-proBNP level and lower ferritin level, GFR (CKD-EPI), SaO
than healthy people. The mean CAVI
was higher in IPAH patients than in the control group- 8.7±1.1 vs 7.5±0.9, P=0.007. Healthy people had significantly less E/e' and lower IVRT. LVET and RVET were shorter in IPAH patients. Patients with IPAH had mean LVGLS -(-17.6±4.8%) and 35.1% of them were with LVGLS ≤16% compared to healthy people -(-21.8±1.4%) and 0%, respectively. LVSR was significant less in IPAH patients, but in the normal range. We found significant correlations of CAVI with age, history of syncope, bilirubin, uric acid, total cholesterol, cardiac output, cardiac index, RVET, LVET and E/A. Multiple linear regression confirmed the independent significance for age (β=0.083±0.023, CI 0.033-0.133) and RVET (β=-0.018±0.005, CI -0.029 to -0.008) only. The risk to have CAVI ≥8 increased in 5.8 times in IPAH patients with RVET <248 ms (P=0.046). CAVI did not correlate with LVGLS and LVSR.
Significant worse systolic and diastolic LV functions were stated in pulmonary hypertensive patients compared to the control group. No LV GLS, no LV SR had significant associations with arterial stiffness evaluated by CAVI.
Novel chiral hybrid perovskites are highly demanded for various advanced applications such as spintronics, optoelectronics, photovoltaics etc . However, the scope of these new materials is still ...limited. Herein, we present new 2D hybrid perovskites based upon chiral α-amino acid l -histidine. The generalized formula of these new compounds can be denoted as ( l -HisH) 2 PbBr x I 4− x (where l -His = l -histidine; x = 4, 3, 2, 1, 0.4 and 0). All perovskites are characterized by a very similar structural motif that consists of corner-sharing lead halide octahedra arranged in one-layer thin inorganic slabs interleaved by organic layers established by l -histidinium(1+) cations. l -Histidine provides a breaking of spatial parity of these perovskites that results in their non-centrosymmetric crystal structures. These compounds show a multiband absorption up to 590 nm for iodide perovskite. In addition, new compounds display pronounced single-peak photoluminescence, which finely blue shifts upon the gradual substitution of iodine by bromine. New perovskites exhibit excellent thermal stability up to 490 K and 445 K for bromide and iodide compounds, respectively. These results show the ability of l -histidine to produce novel and highly demanded chiral hybrid perovskites.
The crystal structure of the title salt, bis(3-carboxy-1-methylpyridinium) octabromide, 2C
7
H
8
NO
2
+
·Br
8
2−
, consists of 3-carboxy-1-methylpyridinium (
N
-methylnicotinic acid) cations, which ...are stacked between relatively rare Br
8
2–
anions. The polybromide Br
8
2–
anion has point group symmetry \overline{1} and can be described as being composed of two Br
3
−
anions connected with a Br
2
molecule in a
Z
-shaped manner. Contacts between neighboring octabromide anions ensure the creation of pseudo-polymeric chains propagating along 111. The organic cations are located between anionic chains and are connected to each other through O—H...O hydrogen bonds and to the Br
8
2–
anions through π...Br interactions that induce the creation of a supramolecular tri-periodic network. In addition, the presence of weak C—H...Br contacts leads to the creation of layers, which align parallel to (11\overline{2}).
A mononuclear square-planar Cu
II
complex of (5-methyl-1
H
-pyrazol-3-yl)carbamate, Cu(C
5
H
6
N
3
O
2
)
2
·4H
2
O, was synthesized using a one-pot reaction from 5-methyl-3-pyrazolamine and ...copper(II) acetate in water under ambient conditions. The adsorption of carbon dioxide from air was facilitated by the addition of diethanolamine to the reaction mixture. While diethanolamine is not a component of the final product, it plays a pivotal role in the reaction by creating an alkaline environment, thereby enabling the adsorption of atmospheric carbon dioxide. The central copper(II) atom is in an (N
2
O
2
) square-planar coordination environment formed by two N atoms and two O atoms of two equivalent (5-methyl-1
H
-pyrazol-3-yl)carbamate ligands. Additionally, there are co-crystallized water molecules within the crystal structure of this compound. These co-crystallized water molecules are linked to the Cu
II
mononuclear complex by O—H...O hydrogen bonds. According to Hirshfeld surface analysis, the most frequently observed weak intermolecular interactions are H...O/O...H (33.6%), H...C/C...H (11.3%) and H...N/N...H (9.0%) contacts.
The aim of this study was to compare the antihypertensive efficacy of losartan 100 mg + hydrochlorothiazide (HCTZ) 25 mg versus bisoprolol 10 mg + HCTZ 25 mg and their influence on arterial stiffness ...and central blood pressure (BP).
Of 60 patients with a mean BP of 173.3 ± 1.7/98.4 ± 1.2 mmHg, 59 were randomized to losartan + HCTZ (n = 32) or bisoprolol + HCTZ (n = 27). Amlodipine was added if target BP was not achieved at 1 month, and doxazosin was added if target BP was not achieved after 3 months. Body mass index, office and 24-hour ambulatory BP, pulse wave velocity (carotid-femoral PWVE and radial PWVM), noninvasive central systolic BP, augmentation index (AIx), laboratory investigations, and electrocardiography were done at baseline and after 6 months of treatment.
Losartan + HCTZ was as effective as bisoprolol + HCTZ, with target office BP achieved in 96.9% and 92.6% of patients and target 24-hour BP in 75% and 66.7% of patients, respectively, after 6 months. Effective treatment of BP led to significant lowering of central systolic BP, but this was decreased to a significantly (P < 0.05) greater extent by losartan + HCTZ (-23.0 ± 2.3 mmHg) than by bisoprolol + HCTZ (-15.4 ± 2.9 mmHg) despite equal lowering of brachial BP. Factors correlated with central systolic BP and its lowering differed between the treatment groups. Losartan + HCTZ did not alter arterial stiffness patterns significantly, but bisoprolol + HCTZ significantly increased AIx. We noted differences in ΔPWVE, ΔPWVM, and ΔAIx between the groups in favor of losartan + HCTZ. Decreased heart rate was associated with higher central systolic BP and AIx in the bisoprolol + HCTZ group, but was not associated with increased AIx in the losartan + HCTZ group.
Although both treatments decreased both office and 24-hour BP, losartan + HCTZ significantly decreased central systolic BP and had a more positive influence on pulse wave velocity, with a less negative effect of decreased heart rate on AIx and central systolic BP.
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