64 research outputs found

    Investigation of ultrafast laser photonic material interactions: challenges for directly written glass photonics

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    Currently, direct-write waveguide fabrication is probably the most widely studied application of femtosecond laser micromachining in transparent dielectrics. Devices such as buried waveguides, power splitters, couplers, gratings and optical amplifiers have all been demonstrated. Waveguide properties depend critically on the sample material properties and writing laser characteristics. In this paper we discuss the challenges facing researchers using the femtosecond laser direct-write technique with specific emphasis being placed on the suitability of fused silica and phosphate glass as device hosts for different applications.Comment: 11 pages, 87 references, 11 figures. Article in revie

    Exceptional Askey-Wilson type polynomials through Darboux-Crum transformations

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    An alternative derivation is presented of the infinitely many exceptional Wilson and Askey-Wilson polynomials, which were introduced by the present authors in 2009. Darboux-Crum transformations intertwining the discrete quantum mechanical systems of the original and the exceptional polynomials play an important role. Infinitely many continuous Hahn polynomials are derived in the same manner. The present method provides a simple proof of the shape invariance of these systems as in the corresponding cases of the exceptional Laguerre and Jacobi polynomials.Comment: 24 pages. Comments and references added. To appear in J.Phys.

    Estimated Inpatient Hospital Stay in Individual Wards: Guidelines on Radiation Safety after Radioiodine Therapy

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    Radionuclide therapy safety requirements are regulated by the Russian Radiation Safety Standards (RRSS), which state the maximum allowed radionuclide activity in the body and the equivalent dose rate (EDR) of gamma radiation. Therefore, it is necessary to estimate the time of an inpatient hospital stay in specially designed radionuclide therapy wards. The article presents the findings of individual 131I biokinetics studies in 64 patients admitted to radioiodine therapy of thyrotoxicosis and differentiated thyroid cancer. We developed a method to calculate the time interval to reach the EDR of 20μSv/h and the recommended EDR of 3 and 0.3μSv/h for adults and children, respectively. It is based on the measurement of the 131I excretion constant. Keywords: Radioiodine therapy, Radiation safety, Guidelin

    A conjecture on Exceptional Orthogonal Polynomials

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    Exceptional orthogonal polynomial systems (X-OPS) arise as eigenfunctions of Sturm-Liouville problems and generalize in this sense the classical families of Hermite, Laguerre and Jacobi. They also generalize the family of CPRS orthogonal polynomials. We formulate the following conjecture: every exceptional orthogonal polynomial system is related to a classical system by a Darboux-Crum transformation. We give a proof of this conjecture for codimension 2 exceptional orthogonal polynomials (X2-OPs). As a by-product of this analysis, we prove a Bochner-type theorem classifying all possible X2-OPS. The classification includes all cases known to date plus some new examples of X2-Laguerre and X2-Jacobi polynomials

    Lanthanoid-doped quaternary garnets as phosphors for high brightness cathodoluminescence-based light sources

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    Gadolinium-yttrium- aluminum-gallium garnets (GYAGG) doped and codoped with Eu, Tb, and Ce were manufactured as ceramics to develop long-wavelength phosphors for high-brightness white light sources based on cathodoluminescence (CL). The CL light yield (LY) of Tb-doped ceramics at high-intensity electron beam excitation is shown to be more than twice as high as that of the conventional phosphor YAG:Ce, whereas codoping with Eu to redshift the chromaticity results in reducing the LY approximately to the level of YAG:Ce. The LY might be substantially improved by using a mix of Tb- and Eu-doped GYGAG powders instead of a single codoped GYGAG to produce ceramic phosphor. The high LY is explained by favorable contribution of Gd sublattice in excitation transfer to activator ions. Chromaticity of phosphors GYGAG:Tb, Eu can be tuned in a wide range by varying the ratio of Tb to Eu concentration. They are radiation resistant and stabile in the temperature range from 300 to 450 K. © 2022 The Author(s)Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-11-2021-070, 075-15-2021-1353, FEUZ-2020-0060This work was supported by the Ministry of Science and Higher Education of the Russian Federation (FEUZ-2020-0060, No. 075-15-2021-1353 & 075-11-2021-070)

    Перспективы адсорбирующей повязки на основе наноструктурированного графита на рынке перевязочных средств России

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    The marketing research has been made to find out the outlooks for commercial activities and market entry for the graphitebased adsorbent dressing. The bandage market increase is caused by the wide application, growing requirement and low price. Domestic cheap ineffective bulky dressings prevail on the market but last years the tendency to the gain in sales of innovative, expensive and effective in treatment import bandages is being observed. The new graphite-based adsorbent dressing has good market prospects in connection with the segment increase, low business competition and high demand of modern effective bandages with adsorbent, wound healing and atraumatic properties.Проведено маркетинговое исследование по перспективности коммерциализации и вывода на отечественный рынок перевязочных средств изделия медицинского назначения «Повязка адсорбирующая» на основе наноструктурированного графита. Рост рынка перевязочных материалов обусловлен широким применением, растущей потребностью и невысокой ценой. Рынок характеризуется высокой долей отечественных дешевых, но малоэффективных перевязочных средств. В последние годы наблюдается тенденция к увеличению продаж инновационных, дорогих и эффективных импортных перевязочных средств. Разработанное коллективом авторов новое перевязочное средство имеет хорошие рыночные перспективы в связи с отмечающимся ростом доли сегмента, низкой конкуренцией и высокой востребованностью современных эффективных перевязочных средств, обладающих адсорбирующими, ранозаживляющими и атравматическими свойствами

    Recent developments in genetics and medically assisted reproduction : from research to clinical applications

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    Two leading European professional societies, the European Society of Human Genetics and the European Society for Human Reproduction and Embryology, have worked together since 2004 to evaluate the impact of fast research advances at the interface of assisted reproduction and genetics, including their application into clinical practice. In September 2016, the expert panel met for the third time. The topics discussed highlighted important issues covering the impacts of expanded carrier screening, direct-to-consumer genetic testing, voiding of the presumed anonymity of gamete donors by advanced genetic testing, advances in the research of genetic causes underlying male and female infertility, utilisation of massively parallel sequencing in preimplantation genetic testing and non-invasive prenatal screening, mitochondrial replacement in human oocytes, and additionally, issues related to cross-generational epigenetic inheritance following IVF and germline genome editing. The resulting paper represents a consensus of both professional societies involved.Peer reviewe
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