In this study, for the first time, we present a systematic study of the critical current density
J
c
at two magnetic field orientations
and
in a single crystal of the superconducting pnictide EuCsFe
...4
As
4
, which shows a magnetic ordering below
T
c
and belongs to the 1144 family. The anisotropy of
J
c
and its temperature dependence are determined. The exponents
of the
dependences from 0.1 to 1 T are in a good agreement with the theoretical predictions for strong Abrikosov vortex pinning, which is also confirmed by the values of the pinning strength estimated using the Dew-Hughes model.
EuCsFe
4
As
4
pnictide (1144 family) single crystals with a critical temperature of
T
c
≈ 36.8 K and optimal superconducting properties in the stoichiometric composition are grown. Multiple-gap ...superconductivity determined by bulk order parameters
,
, and
with characteristic ratios
,
, and
, respectively, is found for the first time below
T
c
using incoherent multiple Andreev reflection effect spectroscopy. It is shown that the gap structure of EuCsFe
4
As
4
is similar to that of BaFe
2 –
x
Ni
x
As
2
superconducting pnictides of the sister 122 family.
—
The magnetic superconductors Dy
0.8
Er
0.2
Rh
3.8
Ru
0.2
B
4
(
T
c
~ 5.1 K) and Dy
0.6
Er
0.4
Rh
3.8
Ru
0.2
B
4
(
T
c
~ 5.8 K) have been prepared by partially substituting Er for Dy in DyRh
3.8
Ru
...0.2
B
4
, and their χ(
Т
),
М
(
B
), and
(
Т
) have been studied in detail. The materials have been shown to undergo an antiferromagnetic transition (at ~3 K) similar to that of the magnetic superconductor DyRh
3.8
Ru
0.2
B
4
. Using magnetic moment vs. magnetic field,
M
(
B
), measurements for Dy
0.8
Er
0.2
Rh
3.8
Ru
0.2
B
4
and Dy
0.6
Er
0.4
Rh
3.8
Ru
0.2
B
4
samples and the Bean model, we have obtained the critical current density as a function of field,
j
c
(
B
), and the reduced pinning force as a function of reduced field,
F
p
(
h
), for the Er-containing materials. The superconductors with antiferromagnetic order in their magnetic subsystem (Dy
0.8
Er
0.2
Rh
3.8
Ru
0.2
B
4
and Dy
0.6
Er
0.4
Rh
3.8
Ru
0.2
B
4
) have been shown to exhibit the largest deviation from the scaling law for
h
> 0.4.
The year 2016 marked the 50th anniversary of the discovery by S. Osaki who first showed that ceruloplasmin (CP, ferro:O
2
-oxidoreductase or ferroxidase) is capable of oxidizing Fe(II) to Fe(III) and ...favors the incorporation of the latter into transferrin (TF). However, much debate remains in the literature concerning the existence of a complex between the enzyme oxidizing iron and the protein facilitating its transport in plasma. We studied CP in exocrine fluids and demonstrated its high-affinity interaction with transferrin found in breast milk and in lacrimal fluid, i.e. with lactoferrin (LF). Here we present data obtained by comparing the interaction of CP with LF and TF using surface plasmon resonance and Hummel–Dreyer chromatography. Binding of apo-LF within the range of concentrations 1.6-51.3 μM with CP immobilized on a CM5-chip is characterized by
K
D
= 1.07 μM. Under similar conditions, the
K
D
for apo-TF was measured and appeared to be higher than 51.3 μM. Hummel–Dreyer chromatography of CP with 51 μM apo-LF/apo-TF in the effluent demonstrated the absence of interaction between apo-TF and CP in solution, contrary to efficient interaction between apoLF and CP. In contrast to LF, the interaction of apo-TF with CP is probably not stable within the physiological range of concentrations of TF.
Novel Iron-Based Superconductor Ca0.5Sm0.5FeAsF Pervakov, K. S.; Kulikova, L. F.; Tsvetkov, A. Yu ...
Bulletin of the Lebedev Physics Institute,
08/2022, Letnik:
49, Številka:
8
Journal Article
Recenzirano
Polycrystalline samples of a novel iron-based 1111-type superconductor Ca
0.5
Sm
0.5
FeAsF are synthesized in an argon atmosphere at a pressure of 50 kbar. This superconducting compound was obtained ...for the first time. The superconducting transition onset temperature of synthesized samples is 54.2 K, which brings the novel compound in line with the highest-temperature ones among all known iron-based superconductors SmFeAs(F,O), GdFeAs(F,O).
A modification of the method of automated validity verification used in debugging parallel programs for computers with distributed memory is proposed. A feature of the proposed approach is the use of ...text erratic behavior templates that make it possible to control the checks performed during the analysis of a running parallel application. A tool implementing the proposed approach to detecting logical errors in parallel programs using the Message Passing Interface is described.
Aim
. To analyze and compare the clinical, echocardiographic characteristics and serum N-terminal pro-brain natriuretic peptide (NT-proBNP) levels depending on the central cardiometabolic risk ...factors, with a focus on obesity, in patients with heart failure (HF) with mid-range ejection fraction (HFmrEF).
Material and methods
. The study included 111 patients with old myocardial infarction and HFmrEF (men, 100%; mean age, 60 years) predominantly of NYHA class II. Echocardiography and blood sampling for NT-proBNP were performed with sinus rhythm. Left atrial volume (LAV) and left ventricular mass (LVM) were indexed to body surface area (BSA) and height raised to a power.
Results
. Type 2 diabetes, overweight and obesity were diagnosed in 25%, 19%, 38% of cases, respectively, and were associated with greater changes in the morphologic and functional left ventricular parameters. There were no intergroup differences among patients with and without obesity in the LAV and LVM indexed to BSA. However, in patients with a body mass index (BMI) ≥30 kg/m
2
, the LAV indexed to height squared and LVM indexed to height
2,7
were higher (p<0,05 for all). In 11% of obese patients, there were no changes in the criterion LAV or LVM values indexed to BSA, but the values indexed to height raised to a power exceeded the standard values. In 20% of patients with clinical manifestations of stable HFmrEF and structural and functional echocardiographic criteria, NT-proBNP were ≤125 pg/ml. An inverse correlation was found between NT-proBNP and BMI (r=-0,29; p=0,008), and lower values of myocardial stress marker were observed in obese patients (p=0,048).
Conclusion
. Considering the high incidence of obesity in patients with HFmrEF and its ability to reduce NT-proBNP, an algorithm modification is required for diagnosing HFmrEF as follows: focus on clinical and personalized echocardiography data, taking into account the obesity and, possibly, indexing the threshold natriuretic peptide values in patients with BMI ≥30 kg/m
2
. The issues of indexation of echocardiographic parameters depending on morphometric parameters in obese patients today remain open, predetermining the limitations in diagnosis of heart failure with left ventricular ejection fraction >40%. This requires the search for optimal standardization and the development of a unified methodological approach.
Magnetic resonances in EuSn2As2 single crystal Golovchanskiy, I.A.; Maltsev, E.I.; Shchetinin, I.V. ...
Journal of magnetism and magnetic materials,
11/2022, Letnik:
562
Journal Article
Recenzirano
Odprti dostop
In this work, we report the broad-band ferromagnetic resonance spectroscopy of EuSn2As2 single crystals at different temperatures in combination with magnetization measurements and structural ...characterization. We observe conventional collective acoustic resonance mode of the A-type antiferromagnetic canted state in the Eu sub-lattice, and its transition to the paramagnetic resonance above the ordering temperature. Furthermore, we observe reproducibly additional well-defined spectral line. The origin of the additional line remains unclear. However, its temperature dependence associates it with the magnetism in the Eu sub-lattice.
•High-quality EuSn2As2 single crystal magnetic bulk topological insulator is grown.•Magnetic resonance spectroscopy of EuSn2As2 is performed.•Antiferromagnetic resonance of the A-type antiferromagnetic Eu sub-lattice is observed.•Additional spectral line of unknown nature is revealed associates with the Eu sub-lattice.
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