549 research outputs found
Optical-electronic System and Software Complex for Research and Identification of Macro- and Micro-optical Elements of Security Holograms
The paper presents an automated optical-electronic software and hardware complex for carrying out activities to identify and control the authenticity of diffraction and holographic optical security elements. The developed complex makes it possible to significantly simplify the work of the expert in conducting forensic studies of objects marked with security holograms
Experimental Demonstration of Compensation of Beam-Beam Effects by Electron Lenses
We report the first experimental demonstration of compensation of beam-beam
interaction effects in high-energy particle collider by using space-charge
forces of a low-energy electron beam. In our experiments, an electron lens, a
novel instrument developed for the beam-beam compensation, was set on a 980-GeV
proton bunch in the Tevatron proton-antiproton collider. The proton bunch
losses due to its interaction with antiproton beam were reduced by a factor of
2 when the electron lens was operating. We describe the principle of electron
lens operation and present experimental results.Comment: submitted to Physical Review Letters, April 2, 2007. submitted to
Physical Review Letters, April 2, 200
Genesis and Prospects of Higher Insurance Education Development in Russia
The article discusses the history and stages of development of insurance education in Russia in comparison with the development of the insurance market in 1990–2020, determines the prospects and conditions for development of insurance education. The internal and external factors that influenced the direction and rate of the market of educational services development in the field of insurance are highlighted, the reasons for the creation and liquidation of specialized departments in Russian universities are analyzed. Based on the analysis of the Russian insurance market in 1990-2020, an understanding of the real and reported indicators of the insurance market is being formed, the differences in which caused at the first stage the creation of a significant number of insurance departments in Russian universities, not supported by a real need for specialists, and then the liquidation of the departments with the loss of the already established competencies for training insurance specialists. In the late 2010s, the modernization processes in the requirements for insurance organizations took place, the financial stability and solvency standards were being raised, mandatory actuarial valuation and new forms of financial reporting were being introduced that required specialized knowledge, basic and professional standards were being developed and adopted with the participation of self-regulatory organizations of insurers. All of that actualized the activities of specialized insurance departments based on the integration of professional requirements fixed in professional and basic standards, and educational standards, which should allow the implementation of economically successful undergraduate and master’s programs.The history of insurance departments in modern Russia may be of interest to researchers of the history of education in modern Russia, the origins and causes of the current state of the educational services market, periods of growth and decline in the number of active players. Based on the analysis of archival and current insurance development strategies, the article highlights the adopted basic and professional standards, prospects for the development of insurance departments, gives recommendations for interaction with professional participants of the insurance market. The revealed trends are also typical for other highly professional departments
Total spectrum of photon emission by an ultra-relativistic positron channeling in a periodically bent crystal
We present the results of numerical calculations of the channelling and
undulator radiation generated by an ultra-relativistic positron channelling
along a crystal plane, which is periodically bent. The bending might be due
either to the propagation of a transverse acoustic wave through the crystal, or
due to the static strain as it occurs in superlattices. The periodically bent
crystal serves as an undulator. We investigate the dependence of the
intensities of both the ordinary channelling and the undulator radiations on
the parameters of the periodically bent channel with simultaneous account for
the dechannelling effect of the positrons. We demonstrate that there is a range
of parameters in which the undulator radiation dominates over the channelling
one and the characteristic frequencies of both types of radiation are well
separated. This result is important, because the undulator radiation can be
used to create a tunable source of X-ray and gamma-radiation.Comment: published in J. Phys. G: Nucl. Part. Phys. 26 (2000) L87-L95,
http://www.iop.org ; 12 pages, 4 figures, LaTe
Composite implants coated with biodegradable polymers prevent stimulating tumor progression
In this experiment we studied oncologic safety of model implants created using the solution blow spinning method with the use of the PURASORB PL-38 polylactic acid polymer and organic mineral filler which was obtained via laser ablation of a solid target made of dibasic calcium phosphate dihydrate. For this purpose the implant was introduced into the area of Wistar rats’ iliums, and on day 17 after the surgery the Walker sarcoma was transplanted into the area of the implant. We evaluated the implant’s influence on the primary tumor growth, hematogenous and lymphogenous metastasis of the Walker sarcoma. In comparison with sham operated animals the implant group demonstrated significant inhibition of hematogenous metastasis on day 34 after the surgery. The metastasis inhibition index (MII) equaled 94% and the metastases growth inhibition index (MGII) equaled 83%. The metastasis frequency of the Walker sarcoma in para aortic lymph nodes in the implant group was not statistically different from the control frequency; there was also no influence of the implant on the primary tumor growth noted. In case of the Walker sarcoma transplantation into the calf and the palmar pad of the ipsilateral limb to the one with the implant in the ilium, we could not note any attraction of tumor cells to the implant area, i.e. stimulation of the Walker sarcoma relapse by the implant. Thus, the research concluded that the studied implant meets the requirements of oncologic safety
Composite implants coated with biodegradable polymers prevent stimulating tumor progression
In this experiment we studied oncologic safety of model implants created using the solution blow spinning method with the use of the PURASORB PL-38 polylactic acid polymer and organic mineral filler which was obtained via laser ablation of a solid target made of dibasic calcium phosphate dihydrate. For this purpose the implant was introduced into the area of Wistar rats’ iliums, and on day 17 after the surgery the Walker sarcoma was transplanted into the area of the implant. We evaluated the implant’s influence on the primary tumor growth, hematogenous and lymphogenous metastasis of the Walker sarcoma. In comparison with sham operated animals the implant group demonstrated significant inhibition of hematogenous metastasis on day 34 after the surgery. The metastasis inhibition index (MII) equaled 94% and the metastases growth inhibition index (MGII) equaled 83%. The metastasis frequency of the Walker sarcoma in para aortic lymph nodes in the implant group was not statistically different from the control frequency; there was also no influence of the implant on the primary tumor growth noted. In case of the Walker sarcoma transplantation into the calf and the palmar pad of the ipsilateral limb to the one with the implant in the ilium, we could not note any attraction of tumor cells to the implant area, i.e. stimulation of the Walker sarcoma relapse by the implant. Thus, the research concluded that the studied implant meets the requirements of oncologic safety
HPV-associated cervical cancer: Current status and prospects
Every year, 570,000 new cases of cervical cancer (CC) are diagnosed in the world, and 311,000 people die from this disease. CC is the fourth most common type of cancer and therefore the fourth leading cause of cancer death in women worldwide. Numerous data on the occurrence and development of cervical cancer indicate an association in most cases (up to 90 %) with human papillomaviruses (HPV) of high carcinogenic risk (HCR).CC prevention strategies are based on screening, and deaths from this oncopathology can be prevented through vaccination and treatment with early detection of the disease.In this review, much attention is paid to current issues of detection and prevention of HPV-associated pathologies, and cervical cancer in particular, aiming to summarize and analyze the latest international literature data on this issue. As a result of this study, it was shown that for countries implementing the National program of vaccination against HPV of high carcinogenic risk, a decrease in the incidence of both cervical pathologies of varying severity and other cancers associated with the HPV carriage was registered.While effective implementation of actual experience and future advances in human papillomavirus vaccine prophylaxis may make it possible for all countries to move to the high levels of vaccination coverage required to eliminate HPV-associated pathologies, the results also suggest that the path to complete cervical cancer elimination as a global public health problem can be extremely difficult due to a number of existing limitations
Search for potential gastric cancer markers using miRNA databases and gene expression analysis
Aim: The aim of this study was to identify genes that are differentially expressed in gastric tumors and to analyze the association of their expression level with tumor clinicopathologic features. Methods: In the present research, we used bioinformatic-driven search to identify miRNA that are down-regulated in gastric tumors and to find their potential targets. Then, the expression levels of some of the target mRNAs were investigated using reverse transcription polymerase chain reaction (RT-PCR) analysis. Results: As a result of the bioinformatics analysis, fifteen genes were found to be potentially differentially expressed between the tumors and normal gastric tissue. Five of them were chosen for the further analysis (WNT4, FGF12, EFEMP1, CTGF, and HSPG2) due to their important role in cell proliferation and differentiation. Expression levels of these genes were evaluated in our collection of frozen tissue samples of gastric tumor and paired normal stomach epithelia. Increased FGF12 expression was observed in diffuse type of gastric cancer while WNT4 mRNA was found to be down-regulated in intestinal type of gastric cancer. Besides, CTGF gene overexpression was revealed in diffuse type of stomach cancer in comparison with that in intestinal type. Up-regulation of CTGF was also associated with lymph node metastasis. Conclusions: The findings show its expedient to perform further investigations in order to clarify diagnostic and prognostic value of CTGF, FGF12, and WNT4’s in stomach cancer as well as the role of these genes in carcinogenesis
The influence of the dechanneling process on the photon emission by an ultra-relativistc positron channeling in a periodically bent crystal
We investigate, both analytically and numerically, the influence of the
dechanneling process on the parameters of undulator radiation generated by
ultra-relativistic positron channelling along a crystal plane, which is
periodically bent. The bending might be due either to the propagation of a
transverse acoustic wave through the crystal, or due to the static strain as it
occurs in superlattices. In either case the periodically bent crystal serves as
an undulator which allows to generate X-ray and gamma-radiation.
We propose the scheme for accurate quantitative treatment of the radiation in
presence of the dechanneling. The scheme includes (i) the analytic expression
for spectral-angular distribution which contains, as a parameter, the
dechanneling length, (ii) the simulation procedure of the dechanneling process
of a positron in periodically bent crystals. Using these we calculate the
dechanneling lengths of 5 GeV positrons channeling in Si, Ge and W crystals,
and the spectral-angular and spectral distributions of the undulator over broad
ranges of the photons. The calculations are performed for various parameters of
the channel bending.Comment: published in J. Phys. G: Nucl. Part. Phys. 27 (2001) 95-125,
http://www.iop.or
One-dimensional Model of a Gamma Klystron
A new scheme for amplification of coherent gamma rays is proposed. The key
elements are crystalline undulators - single crystals with periodically bent
crystallographic planes exposed to a high energy beam of charged particles
undergoing channeling inside the crystals. The scheme consists of two such
crystals separated by a vacuum gap. The beam passes the crystals successively.
The particles perform undulator motion inside the crystals following the
periodic shape of the crystallographic planes. Gamma rays passing the crystals
parallel to the beam get amplified due to interaction with the particles inside
the crystals. The term `gamma klystron' is proposed for the scheme because its
operational principles are similar to those of the optical klystron. A more
simple one-crystal scheme is considered as well for the sake of comparison. It
is shown that the gamma ray amplification in the klystron scheme can be reached
at considerably lower particle densities than in the one-crystal scheme,
provided that the gap between the crystals is sufficiently large.Comment: RevTeX4, 22 pages, 4 figure
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