41 research outputs found
Three-cell traveling wave superconducting test structure
Use of a superconducting traveling wave accelerating (STWA) structure with a
small phase advance per cell rather than a standing wave structure may provide
a significant increase of the accelerating gradient in the ILC linac. For the
same surface electric and magnetic fields the STWA achieves an accelerating
gradient 1.2 larger than TESLA-like standing wave cavities. The STWA allows
also longer acceleration cavities, reducing the number of gaps between them.
However, the STWA structure requires a SC feedback waveguide to return the few
hundreds of MW of circulating RF power from the structure output to the
structure input. A test single-cell cavity with feedback was designed,
manufactured and successfully tested demonstrating the possibility of a proper
processing to achieve a high accelerating gradient. These results open way to
take the next step of the TW SC cavity development: to build and test a
traveling-wave three-cell cavity with a feedback waveguide. The latest results
of the single-cell cavity tests are discussed as well as the design of the test
3-cell TW cavity.Comment: 3 pp. Particle Accelerator, 24th Conference (PAC'11) 28 Mar - 1 Apr
2011: New York, US
Millikelvin measurements of permittivity and loss tangent of lithium niobate
Lithium Niobate is an electro-optic material with many applications in
microwave signal processing, communication, quantum sensing, and quantum
computing. In this letter, we present findings on evaluating the complex
electromagnetic permittivity of lithium niobate at millikelvin temperatures.
Measurements are carried out using a resonant-type method with a
superconducting radio-frequency (SRF) cavity operating at 7 GHz and designed to
characterize anisotropic dielectrics. The relative permittivity tensor and loss
tangent are measured at 50 mK with unprecedented accuracy.Comment: 5 pages, 4 figure
Development of polyresistance in microorganisms during antibiotic therapy in a multidisciplinary hospital during a pandemic COVID-19
Background. Irrational and excessive use of antimicrobials drugs (AMD) creates conditions for the development of a global crisis of health systems around the world associated with antibiotic resistance.
Aim. To conduct a retrospective study of the impact of the use of AMD on the change in the microbiological landscape and the sensitivity of microorganisms in the conditions of pandemic of the new coronavirus infection (COVID-19) in 2020–2021 in intensive care departments (ICD) of a multidisciplinary hospital.
Materials and methods. In the course of the work, strains of microorganisms isolated from patients and from the surfaces of the hospital environment and changes in their sensitivity to significant groups of AMD in ICD for somatic and infectious patients with COVID-19 were compared. The sensitivity of the isolates was evaluated in accordance with the criteria of requirements of European Committee on Antimicrobial Susceptibility Testing – EUCAST, version 10.0, 2020.
Results. A total of 1,394 isolates were studied, including 1,379 clinical and 15 isolates from the surfaces of the hospital environment. It was found that in all ICD in 2020–2021, gram-negative microorganisms prevailed in infectious loci in 70% of cases or more. In 2021, in the ICD in infectious patients with COVID-19, the persistent dominance of the Acinetobacter baumannii microorganism was revealed with an increase in the number of poly- and pan-resistant strains – 48.7%. While in the ICD for somatic patients Klebsiella Pneumoniae prevailed among gram-negative microorganisms – 37.5% in 2020 and 43.7% in 2021. It has been shown that in one department or in adjacent departments of the same medical institution, various nosocomial microorganisms with an unequal set of resistance genes and sensitivity to AMD may appear over time.
Conclusion. The necessity of conducting constant microbiological monitoring and a passport of the medical department with mandatory registration of not only isolated strains of microorganisms, but also resistance genes in order to optimize the appointment of timely adequate empirical antimicrobial therapy is substantiated. The period of the latter should be as short as possible, and confirmed by convincing clinical signs of bacterial infection, and subsequently by the isolation of nosocomial flora from the biomaterial of critical loci from patients
The Dressing Factor and Crossing Equations
We utilize the DHM integral representation for the BES dressing factor of the
world-sheet S-matrix of the AdS_5xS^5 light-cone string theory, and the
crossing equations to fix the principal branch of the dressing factor on the
rapidity torus. The results obtained are further used, in conjunction with the
fusion procedure, to determine the bound state dressing factor of the mirror
theory. We convincingly demonstrate that the mirror bound state S-matrix found
in this way does not depend on the internal structure of a bound state solution
employed in the fusion procedure. This welcome feature is in perfect parallel
to string theory, where the corresponding bound state S-matrix has no bearing
on bound state constituent particles as well. The mirror bound state S-matrix
we found provides the final missing piece in setting up the TBA equations for
the AdS_5xS^5 mirror theory.Comment: LaTex, 48 pages, 10 figures; v2: a new section added where the
dressing factor of the mirror theory is found; v3: formula (6.12) is
corrected, a new figure is added, accepted for publication in J.Phys.
Utilization of an In Vivo Reporter for High Throughput Identification of Branched Small Molecule Regulators of Hypoxic Adaptation
SummarySmall molecules inhibiting hypoxia inducible factor (HIF) prolyl hydroxylases (PHDs) are the focus of drug development efforts directed toward the treatment of ischemia and metabolic imbalance. A cell-based reporter produced by fusing HIF-1α oxygen degradable domain (ODD) to luciferase was shown to work as a capture assay monitoring stability of the overexpressed luciferase-labeled HIF PHD substrate under conditions more physiological than in vitro test tubes. High throughput screening identified novel catechol and oxyquinoline pharmacophores with a “branching motif” immediately adjacent to a Fe-binding motif that fits selectively into the HIF PHD active site in in silico models. In accord with their structure-activity relationship in the primary screen, the best “hits” stabilize HIF1α, upregulate known HIF target genes in a human neuronal line, and exert neuroprotective effects in established model of oxidative stress in cortical neurons
Foundations of the AdS_5 x S^5 Superstring. Part I
We review the recent advances towards finding the spectrum of the AdS_5 x S^5
superstring. We thoroughly explain the theoretical techniques which should be
useful for the ultimate solution of the spectral problem. In certain cases our
exposition is original and cannot be found in the existing literature. The
present Part I deals with foundations of classical string theory in AdS_5 x
S^5, light-cone perturbative quantization and derivation of the exact
light-cone world-sheet scattering matrix.Comment: 161 page
Uniform Light-Cone Gauge for Strings in AdS_5 x S^5: Solving su(1|1) Sector
We introduce a uniform light-cone gauge for strings propagating in AdS
space-time. We use the gauge to analyze strings from the su(1|1) sector, and
show that the reduced model is described by a quadratic action for two complex
fermions. Thus, the uniform light-cone gauge allows us to solve the model
exactly. We analyze the near BMN spectrum of states from the su(1|1) sector and
show that it correctly reproduces the 1/J corrections. We also compute the
spectrum in the strong coupling limit, and derive the famous \lambda^{1/4}
asymptotics. We then show that the same string spectrum can be also derived by
solving Bethe ansatz type equations, and discuss their relation to the quantum
string Bethe ansatz for the su(1|1) sector.Comment: 26 pages, Latex, v2: comparison to the strong coupling expansion of
the quantum string Bethe ansatz is added, discussion of the winding sector is
extended, references adde
Konishi operator at intermediate coupling
TBA equations for two-particle states from the sl(2) sector proposed by
Arutyunov, Suzuki and the author are solved numerically for the Konishi
operator descendent up to 't Hooft's coupling lambda ~ 2046. The data obtained
is used to analyze the properties of Y-functions and address the issue of the
existence of the critical values of the coupling. In addition we find a new
integral representation for the BES dressing phase which substantially reduces
the computational time.Comment: lots of figures, v2: improved numerics, c1=2, c2=0, c4 does not
vanis
Treatment of toxic hepatitis in COVID-19 patients
Background. The article reflects the clinical significance of the early diagnosis of toxic hepatitis in patients who have undergone a new coronavirus infection with the determination of clinical and laboratory predictors of the response to therapy. A dynamic analysis of the effectiveness of toxic hepatitis therapy in patients of three experimental groups and a control group is presented.
Aim. The aim of the present study is to increase the effectiveness of the treatment of toxic hepatitis in patients who have undergone COVID-19.
Materials and methods. On the basis of the newly created infection centers of the Central Clinical Hospital RZhD-Medicine and Vishnevsky 3-rd Central Military Clinical Hospital 996 patients with COVID-19, who had clinical and laboratory signs of toxic liver damage (cytolytic and/or cholestatic syndromes) against the background of COVID-19 therapy.
Results. On the 14th day from the start of therapy in group 3, there was a significant decrease in the clinical manifestations of jaundice in 163 (72.8%) patients, on the 21st day of treatment, this symptom was stopped in all patients. In groups 1 and 2, the decrease in clinical manifestations of jaundice was significantly lower 122 (55.2%) and 134 (58.8%); p0.05. At the end of therapy, no manifestations of jaundice were observed in all experimental groups, while in the control group, symptom reduction was achieved only in 47 (14.5%) patients.
Conclusion. The use of drugs with hepatoprotective effect in the form of monotherapy in groups 1 (UDCA) and 2 (ademethionine) showed a low therapeutic effect with positive dynamics of clinical and laboratory indicators of toxic hepatitis activity. The use of combined treatment in group 3 (UDCA and ademethionine) demonstrated the maximum therapeutic effect, pronounced positive dynamics in the form of normalization of clinical and laboratory indicators of toxic hepatitis activity
Structural And Optical Properties Of n-Type and p-Type GaAs(1−x)Bix Thin Films Grown By Molecular Beam Epitaxy On (311)B GaAs Substrates
In this paper, we report on the structural and optical properties of n-type Si-doped and p-type Be-doped GaAs(1−x)Bix thin films grown by molecular beam epitaxy on (311)B GaAs substrates with nominal Bi content x=5.4%. Similar samples without Bi were also grown for comparison purposes (n-type GaAs and p-type GaAs). X-ray diffraction, micro-Raman at room temperature, and photoluminescence (PL) measurements as a function of temperature and laser excitation power (PEXC) were performed to investigate their structural and optical properties. X-ray diffraction results revealed that the Bi incorporation in both n-type and p-type doped GaAsBi was similar, despite that the samples present remarkable differences in the number of Bi related defects, non-radiative centers and alloy disorder. Particularly, our results evidence that the Bi-related defects in n- and p-doped GaAsBi alloys have important impact on the differences of their optical properties