2,304 research outputs found
Role of a decrease in body heat content in the thermoregulatory reaction of the concha auriculae vessels
At the constant ambient temperature 28-30 C the rabbit ear vessels were dilated and their temperature was 34.8/0.1 C. Administration of the 23-29 C water into the stomach entailed thermoregulatory construction of the ear vessels within 15-25 min. The response occurred at various combinations of temperature changes in different parts of the body. The heat content of the rabbit body, as calculated by the blood temperature in the aorta arc, reduced by 266.3 + or - 26.2 cal/kg at the beginning of the response. The decrease in the organism heat content seems to serve as a signal for occurrence of a corresponding thermoregulatory response
Gas Sensing with h-BN Capped MoS2 Heterostructure Thin Film Transistors
We have demonstrated selective gas sensing with molybdenum disulfide (MoS2)
thin films transistors capped with a thin layer of hexagonal boron nitride
(h-BN). The resistance change was used as a sensing parameter to detect
chemical vapors such as ethanol, acetonitrile, toluene, chloroform and
methanol. It was found that h-BN dielectric passivation layer does not prevent
gas detection via changes in the source-drain current in the active MoS2 thin
film channel. The use of h-BN cap layers (thickness H=10 nm) in the design of
MoS2 thin film gas sensors improves device stability and prevents device
degradation due to environmental and chemical exposure. The obtained results
are important for applications of van der Waals materials in chemical and
biological sensing.Comment: 3 pages; 4 figure
Low-noise top-gate graphene transistors
We report results of experimental investigation of the low-frequency noise in
the top-gate graphene transistors. The back-gate graphene devices were modified
via addition of the top gate separated by 20 nm of HfO2 from the single-layer
graphene channels. The measurements revealed low flicker noise levels with the
normalized noise spectral density close to 1/f (f is the frequency) and Hooge
parameter below 2 x 10^-3. The analysis of the noise spectral density
dependence on the top and bottom gate biases helped us to elucidate the noise
sources in these devices and develop a strategy for the electronic noise
reduction. The obtained results are important for all proposed graphene
applications in electronics and sensors.Comment: 9 pages, 4 figure
Influence of the photon - neutrino processes on magnetar cooling
The photon-neutrino processes ,
and are investigated
in the presence of a strongly magnetized and dense electron-positron plasma.
The amplitudes of the reactions and
are obtained. In the case of a cold degenerate
plasma contributions of the considering processes to neutrino emissivity are
calculated. It is shown that contribution of the process to neutrino emissivity is supressed in comparision with the
contributions of the processes and
. The constraint on the magnetic field strength in the
magnetar outer crust is obtained.Comment: 8 pages, LaTeX, 2 PS figures, based on the talk presented by D.A.
Rumyantsev at the XV International Seminar Quarks'2008, Sergiev Posad, Moscow
Region, May 23-29, 2008, to appear in the Proceeding
Development of oncology: from despair to hope...
Key words: oncology, chemotherapy, radiotherapy, surgery, target therapy, clinical trials, histor
Quantum coherence and interaction-free measurements
We investigate the extent to which ``interaction-free'' measurements perturb
the state of quantum systems. We show that the absence of energy exchange
during the measurement is not a sufficient criterion to preserve that state, as
the quantum system is subject to measurement dependent decoherence. While it is
possible in general to design interaction-free measurement schemes that do
preserve that state, the requirement of quantum coherence preservation rapidly
leads to a very low efficiency. Our results, which have a simple interpretation
in terms of ``which-way'' arguments, open up the way to novel quantum
non-demolition techniques.Comment: 4 pages incl. 2 PostScript figures (.eps), LaTeX using RevTeX,
submitted to Phys. Rev. A (Rapid Comm.
Observation of the "Memory Steps" in Graphene at Elevated Temperatures
We found that the current-voltage characteristics of the single-layer
graphene field-effect transistors exhibit an intriguing feature - an abrupt
change of the current near zero gate bias at elevated temperatures T > 500 K.
The strength of the effect - referred to as the "memory step" by analogy with
the "memory dips" - known phenomenon in electron glasses - depends on the rate
of the voltage sweep. The slower the sweep - the more pronounced is the step in
the current. Despite differences in examined graphene transistor
characteristics, the "memory step" always appears near zero gate bias. The
effect is reproducible and preserved after device aging. A similar feature has
been previously observed in electronic glasses albeit at cryogenic temperatures
and with opposite dependence on the rate of the voltage sweep. The observed
"memory step" can be related to the slow relaxation processes in graphene. This
new characteristic of electron transport in graphene can be used for
applications in high-temperature sensors and switches.Comment: 17 manuscript page
Results of a search for 2-decay of Xe with high-pressure copper proportional counters in Baksan Neutrino Observatory
The experiment for the 2-decay of Xe search with two
high-pressure copper proportional counters has been held in Baksan neutrino
observatory. The search for the process is based on comparison of spectra
measured with natural and enriched xenon. No evidence has been found for
2(2)- and 2(0)-decay. The decay half lifetime limit
based on data measured during 8000 h is Tyr for
2-mode and Tyr for 0-mode (90%C.L.).Comment: 9 pages, 8 figures; talk at the NANP'05 Conference; submitted to
Phys. At. Nuc
The current state of the problem of soft tissue defects replacement in the lower extremities in conditions of chronic osteomyelitis
Based on the data of scientific literature, the current state of the problem of soft tissue defects replacement in the lower extremities in conditions of chronic osteomyelitis has been analyzed. Taking into account certain requirements for the replacement of defects of this nature, the following reconstructive tasks have been indicated. First of all, for adequate restoration of the skin with simultaneous relief of the purulent-necrotic process, it is necessary to use blood-supplied tissue complexes, which, if possible, should be formed from tissues similar to those surrounding the defect. The predominant use of technically and economically beneficial interventions is of great importance. The most suitable are loco-regional flaps with axial blood supply, among which the most promising are perforant flaps. It is necessary to develop an algorithm for defects reconstruction using loco-regional perforant flaps, depending on the defect area. It is also necessary to conduct a comparative analysis of the anatomical advantages and effectiveness of using various perforant and insular flaps on the vascular pedicle. A one-stage orthoplastic approach will allow the most effective use of the achievements of reconstructive plastic surgery in orthopedics to restore limb function, which will improve the results of treatment of patients
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