489 research outputs found
USE OF BETA BLOCKERS IN ACUTE CORONARY SYNDROME IN SERBIA IN THE PERIOD 2000 – 2005
The approaches in prevention and therapy of acute coronary syndrome (ACS) are different ways of conservative and invasive procedures which have contributed to reduction of mortality of ischemic heart disease (IHD) by 20 %, approximately, in many parts of the world in the recent 20 years. Beta blockers (BB) gave significant contribution to prevention and therapy of ACS, especially their use in ACS and in the first years of secondary prevention of IHD. The aim of the study was the estimation of patients with ACS in Serbia in the period 2000 – 2005, as well as the evaluation of use of BB in ACS and resolving dilemma concerning their prescription.The data about patients were obtained from the National Register for ACS in Serbia. Lately, there has been a marked increase in the number of coronary units (CU) and patients with ACS. In admission diagnoses, there was the largest number of patients with AMI or 69,7 %, with the highest total mortality of 11,7 %. In addition, higher rates of male patients than female ones, as well as an increase of male patients in the age group of 50-59 years, and increase of female patients in the age group of 70-79 years were reported. It is interesting that the rate of female patients is higher than presented in literature. It is noted that the rate of AMI with ST segment elevation (STEMI) is more frequent than AMI without ST elevation (NSTEMI). STEMI is more frequent in younger patients and male ones. Case-fatality of STEMI patients is significantly higher compared with NSTEMI patients (P<0,000). The percentage of patients with ACS treated with BB is still low and it has not been changed significantly in recent years
Mirror-Curves and Knot Mosaics
Inspired by the paper on quantum knots and knot mosaics [23] and grid
diagrams (or arc presentations), used extensively in the computations of
Heegaard-Floer knot homology [2,3,7,24], we construct the more concise
representation of knot mosaics and grid diagrams via mirror-curves. Tame knot
theory is equivalent to knot mosaics [23], mirror-curves, and grid diagrams
[3,7,22,24]. Hence, we introduce codes for mirror-curves treated as knot or
link diagrams placed in rectangular square grids, suitable for software
implementation. We provide tables of minimal mirror-curve codes for knots and
links obtained from rectangular grids of size 3x3 and px2 (p<5), and describe
an efficient algorithm for computing the Kauffman bracket and L-polynomials
[18,19,20] directly from mirror-curve representations
specific targeted integration of kanamycin resistance associated nonselectable dna in the genome of the yeast saccharomyces cerevisiae
ABSTRACT Sophisticated genome manipulation re-quires the possibility to modify any inter-genic or intragenic DNA sequence at will,without leaving large amounts of undesiredvector DNA at the site of alteration. To thisend, a series of vectors was developed froma previous gene knockout plasmid system tointegrate nonselectable foreign DNA at anydesired genomic location in yeast, with aminimum amount of residual plasmid DNA.These vectors have two mutated Flp recog-nition targets ( FRT ) sequences flanking the KanMX4 gene and multiple sites for sub-cloning the DNA fragment to be integrated.The selectable marker can be recycled byFlp site-specific excision between the iden-tical FRT s, thereby allowing the integrationof further DNA fragments. With this system,the NLS-tetR-GFP and DsRed genes weresuccessfully integrated at the thr1 locus,and the RVB1 gene was tagged at the C-terminus with the V5-epitope-6-histidinetag. This plasmid system provides for a newmolecular tool to integrate any DNA frag-ment at any genome location in
Observation of Weyl nodes in robust type-II Weyl semimetal WP2
Distinct to type-I Weyl semimetals (WSMs) that host quasiparticles described
by the Weyl equation, the energy dispersion of quasiparticles in type-II WSMs
violates Lorentz invariance and the Weyl cones in the momentum space are
tilted. Since it was proposed that type-II Weyl fermions could emerge from
(W,Mo)Te2 and (W,Mo)P2 families of materials, a large numbers of experiments
have been dedicated to unveil the possible manifestation of type-II WSM, e.g.
the surface-state Fermi arcs. However, the interpretations of the experimental
results are very controversial. Here, using angle-resolved photoemission
spectroscopy supported by the first-principles calculations, we probe the
tilted Weyl cone bands in the bulk electronic structure of WP2 directly, which
are at the origin of Fermi arcs at the surfaces and transport properties
related to the chiral anomaly in type-II WSMs. Our results ascertain that due
to the spin-orbit coupling the Weyl nodes originate from the splitting of
4-fold degenerate band-crossing points with Chern numbers C = 2 induced by
the crystal symmetries of WP2, which is unique among all the discovered WSMs.
Our finding also provides a guiding line to observe the chiral anomaly which
could manifest in novel transport properties.Comment: 13 pages, 3 figure
Bulk electronic structure of superconducting LaRu2P2 single crystals measured by soft x-ray angle-resolved photoemission spectroscopy
We present a soft X-ray angle-resolved photoemission spectroscopy (SX-ARPES)
study of the stoichiometric pnictide superconductor LaRu2P2. The observed
electronic structure is in good agreement with density functional theory (DFT)
calculations. However, it is significantly different from its counterpart in
high-temperature superconducting Fe-pnictides. In particular the bandwidth
renormalization present in the Fe-pnictides (~2 - 3) is negligible in LaRu2P2
even though the mass enhancement is similar in both systems. Our results
suggest that the superconductivity in LaRu2P2 has a different origin with
respect to the iron pnictides. Finally we demonstrate that the increased
probing depth of SX-ARPES, compared to the widely used ultraviolet ARPES, is
essential in determining the bulk electronic structure in the experiment.Comment: 4 pages, 4 figures, 1 supplemental material. Accepted for publication
in Physical Review Letter
Interfacial and thickness effects in LaSrMnO/YBaCuO superlattices
Superlattices of correlated oxides have been used to explore interfacial
effects and to achieve additional control over the physical properties of
individual constituents. In this work, we present a first-principles
perspective of the strain and thickness effects in
LaSrMnO/YBaCuO (LSMO/YBCO) superlattices. Our
findings indicate that the presence of epitaxial strain and LSMO leads to a
reduction of buckling parameters of the interfacial CuO planes, as well as
the transfer of electrons from LSMO to YBCO. In addition, the change in Cu-3
valence is slightly dependent on the LSMO layer thickness. More interestingly,
the in-plane ferromagnetic ground state within the CuO planes near the
interface is induced due to the local moments centered at the copper atoms.
These local moments are decoupled from the charge transfer and, according to
our calculations, appear mainly due to the Mn -O -Cu hybridization
being restricted to the interfacial region. The induced net magnetic ordering
in interfacial copper atoms may have implications in the control of the
superconducting state in the LSMO/YBCO superlattices
Exotic Kondo crossover in a wide temperature region in the topological Kondo insulator SmB6 revealed by high-resolution ARPES
Temperature dependence of the electronic structure of SmB6 is studied by
high-resolution ARPES down to 1 K. We demonstrate that there is no essential
difference for the dispersions of the surface states below and above the
resistivity saturating anomaly (~ 3.5 K). Quantitative analyses of the surface
states indicate that the quasi-particle scattering rate increases linearly as a
function of temperature and binding energy, which differs from Fermi-Liquid
behavior. Most intriguingly, we observe that the hybridization between the d
and f states builds gradually over a wide temperature region (30 K < T < 110
K). The surface states appear when the hybridization starts to develop. Our
detailed temperature-dependence results give a complete interpretation of the
exotic resistivity result of SmB6, as well as the discrepancies among
experimental results concerning the temperature regions in which the
topological surface states emerge and the Kondo gap opens, and give new
insights into the exotic Kondo crossover and its relationship with the
topological surface states in the topological Kondo insulator SmB6.Comment: 8 pages, 5 figure
Trivial topological phase of CaAgP and the topological nodal-line transition in CaAg(P1-xAsx)
By performing angle-resolved photoemission spectroscopy and first-principles
calculations, we address the topological phase of CaAgP and investigate the
topological phase transition in CaAg(P1-xAsx). We reveal that in CaAgP, the
bulk band gap and surface states with a large bandwidth are topologically
trivial, in agreement with hybrid density functional theory calculations. The
calculations also indicate that application of "negative" hydrostatic pressure
can transform trivial semiconducting CaAgP into an ideal topological nodal-line
semimetal phase. The topological transition can be realized by partial
isovalent P/As substitution at x = 0.38.Comment: 20 pages, 4 figure
Ru layers electrodeposited onto highly stable Ti2AlC substrates as cathodes for hydrogen evolution in sulfuric acid solutions
In this work, the hydrogen evolution reaction (HER) was studied on Ru coated Ti2AlC electrodes in 1.0 mol dm(-3) H2SO4 at 25 degrees C. Ti2AlC was found to be a highly stable substrate in sulfuric acid solutions due to the formation of a passivating oxide layer on the surface, which was confirmed by the X-ray photoelectron spectroscopy (XPS) analysis of as-prepared and anodically treated Ti2AlC samples. Ru films were electrodeposited onto Ti2AlC substrates by cycling the potential of Ti2AlC in the solution containing 0.01 mol dm(-3) RuCl3 + 0.1 mol dm(-3) H2SO4 between -0.5 V and 0.4 V vs. a saturated calomel electrode (SCE) at the sweep rate of 20 mV s(-1). Four Ru/Ti2AlC samples were prepared, obtained at 5, 10, 15 and 20 cycles of Ru electrodeposition. Characterization of samples was performed by scanning electron microscopy (SEM) and cyclic voltammetry (CV), while the thickness of the electrodeposited Ru layers was determined by atomic force microscopy (AFM). It was found that the most compact sample with the thickness of about 0.42 mu m was obtained after 5 cycles. Electrochemical impedance spectroscopy (EIS) and steady-state polarization measurements showed that all Ru/Ti2AlC electrodes were exceptionally active for the HER. A Tafel slope of about -60 mV dec(-1) was observed on all polarization curves in the range of high cathodic current densities. Based on formal kinetics analysis, an appropriate mechanism for the HER on Ru/Ti2AlC was suggested.This is the peer-reviewed version of the article: Jovic, B. M., Jović, V. D., Lačnjevac, U., Stevanović, S., Kovac, J., Radovic, M.,& Krstajić, N. V. (2016). Ru layers electrodeposited onto highly stable Ti2AlC substrates as cathodes for hydrogen evolution in sulfuric acid solutions. Journal of Electroanalytical Chemistry, Elsevier, 766, 78-86. [https://doi.org/10.1016/j.jelechem.2016.01.038]The published version: [https://cer.ihtm.bg.ac.rs/handle/123456789/2012
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