Resonant third harmonic generation of KrF laser in Ar gas

Investigations of emission of harmonics from argon gas jet irradiated by 700 fs, 5 mJ pulses from a KrF laser are presented. Harmonics conversion was optimized by varying the experimental geometry and the nozzle size. For the collection of the harmonic radiation silicon and solar-blind diamond semiconductor detectors equipped with charge preamplifiers were applied. The possibility of using a single-crystal CVD diamond detector for separate measurement of the 3rd harmonic in the presence of a strong pumping radiation was explored. Our experiments show that the earlier suggested 0.7% conversion efficiency can really be obtained, but only in the case when phase matching is optimized with an elongated gas target length corresponding to the length of coherence

A quantum model of charge capture and release onto/from deep traps

The rapid development of optical technologies and applications revealed the critical role of point defects affecting device performance. One of the powerful tools to study influence of defects on charge capture and recombination processes is thermoluminescence. The popular models behind thermoluminescence and carrier capture processes are semi-classic though. They offer good qualitative description, but implicitly exclude quantum nature of the accompanying parameters, such as frequency factors and capture cross sections. As a consequence, results obtained for a specific host material cannot be successfully extrapolated to other materials. Thus, the main purpose of our work is to introduce a reliable analytical model that describes non-radiative capture and release of electrons from/to the conduction band (CB). The proposed model is governed by Bose-Einstein statistics (for phonon occupation) and Fermi's golden rule (for resonant charge transfer between the trap and the CB). The constructed model offers a physical interpretation of the capture coefficients and frequency factors, and seamlessly includes the Coulomb neutral/attractive nature of traps. It connects the frequency factor to the overlap of wavefunctions of the delocalized CB and trap states, and suggests a strong dependence on the density of charge distribution, i.e. the ionicity/covalency of the chemical bonds within the host. Separation of the resonance condition from the accumulation/dissipation of phonons on the site leads to the conclusion that the capture cross-section does not necessarily depend on the trap depth. The model is verified by comparison to reported experimental data, showing good agreement. As such, the model generates reliable information about trap states whose exact nature is not completely understood and allows to do materials research in a more systematic way

Spotlight on luminescence thermometry: basics, challenges, and cutting-edge applications

No abstract available

Sterilizálási lehetőségek a fogászatban. Rugalmas anyagok csírátlanításának korlátai egy eset kapcsán = Sterilization in dentistry Limitations of elastic materials: a case presentation

Absztrakt: A mindennapi fogászati praxisban igen fontos a sterilitás. Az egyes eszközök és anyagok csírátlanítása azonban eltérő módszereket igényel. A hőérzékeny és rugalmas, elasztikus anyagok esetén a legelterjedtebb sterilizálási módok azért nem használhatók, mert alacsonyabb hőmérsékletű sterilizálás szükséges, hogy ne veszítsék el eredeti fizikai tulajdonságaikat. Ezen anyagok közé tartozik a kofferdam lepedő is, mely rugalmasságától megfosztva alkalmatlanná válik izolálási feladatának ellátására a fogmegtartó kezelések során. Gumilepedő csírátlanítására ritkán kerül sor, bizonyos esetek megoldása azonban megkívánhatja azt. Ilyen szituációban a fogorvosnak viszonylag limitált, sokszor nehezen elérhető eszköztárból kell választania. Közleményünk sorra veszi a sterilizálóeljárásokat, különös figyelmet szentelve a plazmasterilizálásnak, illetve a hidrogén-peroxid-gázt használó eljárásoknak. Esetbemutatásunkban egy kiterjedt, a fog koronai és gyökéri területét is érintő ínyszél alá terjedő fraktúra ellátása során az adhezív technika alkalmazhatóságát hidrogén-peroxid-gázt használó készülékben sterilizált kofferdam lepedő felhelyezésével biztosítottuk. Orv Hetil. 2020; 161(3): 110–115. | Abstract: In everyday dental practice, sterility is essential. Sterilizing different materials can require different methods. In the case of heat sensitive and elastic materials, most common techniques are not suitable because they need to be treated on lower temperature, not to lose their physical properties. For instance, if rubber dam is divested of elasticity, it is useless in restorative dentistry thereafter. Sterilizing rubber dam sheets is not a frequent process, but in certain cases it can be necessary. In such a situation, dentists have to choose between rare and hard-to-reach options. In our referral, we summarize the possibilities of sterilization, focusing on plasma sterilization and hydrogen-peroxide vapor sterilization. During the treatment of our presented case with a deep subgingival fracture line, affecting the crown and the root surface as well, we applied a rubber dam sheet, sterilized with hydrogen-peroxide vapor in order to use adhesive technique. Orv Hetil. 2020; 161(3): 110–115

Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study

Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality

Progress on lead-free metal halide perovskites for photovoltaic applications: a review

ABSTRACT: Metal halide perovskites have revolutionized the field of solution-processable photovoltaics. Within just a few years, the power conversion efficiencies of perovskite-based solar cells have been improved significantly to over 20%, which makes them now already comparably efficient to silicon-based photovoltaics. This breakthrough in solution-based photovoltaics, however, has the drawback that these high efficiencies can only be obtained with lead-based perovskites and this will arguably be a substantial hurdle for various applications of perovskite-based photovoltaics and their acceptance in society, even though the amounts of lead in the solar cells are low. This fact opened up a new research field on lead-free metal halide perovskites, which is currently remarkably vivid. We took this as incentive to review this emerging research field and discuss possible alternative elements to replace lead in metal halide perovskites and the properties of the corresponding perovskite materials based on recent theoretical and experimental studies. Up to now, tin-based perovskites turned out to be most promising in terms of power conversion efficiency; however, also the toxicity of these tin-based perovskites is argued. In the focus of the research community are other elements as well including germanium, copper, antimony, or bismuth, and the corresponding perovskite compounds are already showing promising properties. GRAPHICAL ABSTRACT: [Image: see text

Neural processing of natural sounds

Natural sounds include animal vocalizations, environmental sounds such as wind, water and fire noises and non-vocal sounds made by animals and humans for communication. These natural sounds have characteristic statistical properties that make them perceptually salient and that drive auditory neurons in optimal regimes for information transmission.Recent advances in statistics and computer sciences have allowed neuro-physiologists to extract the stimulus-response function of complex auditory neurons from responses to natural sounds. These studies have shown a hierarchical processing that leads to the neural detection of progressively more complex natural sound features and have demonstrated the importance of the acoustical and behavioral contexts for the neural responses.High-level auditory neurons have shown to be exquisitely selective for conspecific calls. This fine selectivity could play an important role for species recognition, for vocal learning in songbirds and, in the case of the bats, for the processing of the sounds used in echolocation. Research that investigates how communication sounds are categorized into behaviorally meaningful groups (e.g. call types in animals, words in human speech) remains in its infancy.Animals and humans also excel at separating communication sounds from each other and from background noise. Neurons that detect communication calls in noise have been found but the neural computations involved in sound source separation and natural auditory scene analysis remain overall poorly understood. Thus, future auditory research will have to focus not only on how natural sounds are processed by the auditory system but also on the computations that allow for this processing to occur in natural listening situations.The complexity of the computations needed in the natural hearing task might require a high-dimensional representation provided by ensemble of neurons and the use of natural sounds might be the best solution for understanding the ensemble neural code

Sterilizálási lehetőségek a fogászatban. Rugalmas anyagok csírátlanításának korlátai egy eset kapcsán

Absztrakt: A mindennapi fogászati praxisban igen fontos a sterilitás. Az egyes eszközök és anyagok csírátlanítása azonban eltérő módszereket igényel. A hőérzékeny és rugalmas, elasztikus anyagok esetén a legelterjedtebb sterilizálási módok azért nem használhatók, mert alacsonyabb hőmérsékletű sterilizálás szükséges, hogy ne veszítsék el eredeti fizikai tulajdonságaikat. Ezen anyagok közé tartozik a kofferdam lepedő is, mely rugalmasságától megfosztva alkalmatlanná válik izolálási feladatának ellátására a fogmegtartó kezelések során. Gumilepedő csírátlanítására ritkán kerül sor, bizonyos esetek megoldása azonban megkívánhatja azt. Ilyen szituációban a fogorvosnak viszonylag limitált, sokszor nehezen elérhető eszköztárból kell választania. Közleményünk sorra veszi a sterilizálóeljárásokat, különös figyelmet szentelve a plazmasterilizálásnak, illetve a hidrogén-peroxid-gázt használó eljárásoknak. Esetbemutatásunkban egy kiterjedt, a fog koronai és gyökéri területét is érintő ínyszél alá terjedő fraktúra ellátása során az adhezív technika alkalmazhatóságát hidrogén-peroxid-gázt használó készülékben sterilizált kofferdam lepedő felhelyezésével biztosítottuk. Orv Hetil. 2020; 161(3): 110–115.</jats:p