Selective oxidation of bulky organic sulphides over layered titanosilicate catalysts

The authors acknowledge the Czech Science Foundation (P106/12/G015) for the financial support.Selective oxidation of sulphides is a straightforward method of preparation of organic sulphoxides and sulphones, which are important chemical intermediates and building blocks of pharmaceuticals and agrochemicals. Oxidation of methylphenyl sulphide (MPS), diphenyl sulphide (Ph2S), and dibenzothiophene (DBTH) over lamellar titanosilicate catalysts with the MFI and UTL-derived topology was investigated with hydrogen peroxide as the oxidant. Lamellar titanosilicates combine the advantages of crystalline zeolites and mesoporous molecular sieves due to accessible active sites located on the external surface of their layers. The selectivity of the MPS oxidation to methylphenyl sulphoxide is driven by the diffusion restrictions in the catalyst. A methylphenyl sulphoxide selectivity of 95% at 40% conversion was achieved using the Ti-IPC-1-PI catalyst together with an outstanding TONtot = 1418 after 30 min. The selectivity can be adjusted also by dosing of the oxidant to keep its concentration low during the reaction. The silica-titania pillared TS-1-PITi catalyst showed the highest potential of the tested catalysts in oxidative desulphuration, easily oxidising the DBTH to dibenzothiothene sulphone.PostprintPeer reviewe

Selective oxidation of bulky organic sulphides over layered titanosilicate catalysts

The authors acknowledge the Czech Science Foundation (P106/12/G015) for the financial support.Selective oxidation of sulphides is a straightforward method of preparation of organic sulphoxides and sulphones, which are important chemical intermediates and building blocks of pharmaceuticals and agrochemicals. Oxidation of methylphenyl sulphide (MPS), diphenyl sulphide (Ph2S), and dibenzothiophene (DBTH) over lamellar titanosilicate catalysts with the MFI and UTL-derived topology was investigated with hydrogen peroxide as the oxidant. Lamellar titanosilicates combine the advantages of crystalline zeolites and mesoporous molecular sieves due to accessible active sites located on the external surface of their layers. The selectivity of the MPS oxidation to methylphenyl sulphoxide is driven by the diffusion restrictions in the catalyst. A methylphenyl sulphoxide selectivity of 95% at 40% conversion was achieved using the Ti-IPC-1-PI catalyst together with an outstanding TONtot = 1418 after 30 min. The selectivity can be adjusted also by dosing of the oxidant to keep its concentration low during the reaction. The silica-titania pillared TS-1-PITi catalyst showed the highest potential of the tested catalysts in oxidative desulphuration, easily oxidising the DBTH to dibenzothiothene sulphone.PostprintPeer reviewe

Asymmetric Magnetosphere Deformation Driven by Hot Flow Anomaly(ies)

We present a case study of a large deformation of the magnetopause on November 26, 2008. The investigation is based on observations of five THEMIS spacecraft located at the dawn flank in the magnetosphere and magnetosheath, on Cluster measurements at the dusk magnetosheath, and is supported by ACE solar wind monitoring. The main revelation of our study is that the interaction of the IMF discontinuity with the bow shock creates either one very elongated hot flow anomaly (HFA) or a pair of them that is (are) simultaneously observed at both flanks. Whereas the dusk HFA is weak and does not cause observable deformation of the magnetopause, the pressure variations connected with the dawn HFA lead to a magnetopause displacement by approx. = 5 R(sub E) outward from its nominal position. This is followed by a rapid inward motion of the magnetopause approx. = 4 R(sub E) inward with respect to the model location. The surface deformation is so large that the outermost THEMIS spacecraft was in the magnetosphere, whereas the spacecraft located 9 R(sub E) inbound entered into the magnetosheath at the same time. The whole event lasted about 5 minutes

Nieoczekiwane zwolnienia rytmu w stymulatorach dwujamowych spowodowane obecnością arytmii nadkomorowych

W niektórych modelach stymulatorów dwujamowych firmy Biotronik, w obecności arytmii nadkomorowych, odstęp pomiędzy kolejnymi zdarzeniami w torze komorowym (odstęp RR) może sporadycznie być znacznie dłuższy niż odstęp wynikający z zaprogramowanej częstości podstawowej stymulatora. Opisujemy to nieoczekiwane zachowanie, które zaobserwowano u 3 pacjentów. Mechanizm ten należy uwzględnić podczas kontroli chorych jako możliwą przyczynę wydłużania się odstępów RR

Nieoczekiwane zwolnienia rytmu w stymulatorach dwujamowych spowodowane obecnością arytmii nadkomorowych

W niektórych modelach stymulatorów dwujamowych firmy Biotronik, w obecności arytmii nadkomorowych, odstęp pomiędzy kolejnymi zdarzeniami w torze komorowym (odstęp RR) może sporadycznie być znacznie dłuższy niż odstęp wynikający z zaprogramowanej częstości podstawowej stymulatora. Opisujemy to nieoczekiwane zachowanie, które zaobserwowano u 3 pacjentów. Mechanizm ten należy uwzględnić podczas kontroli chorych jako możliwą przyczynę wydłużania się odstępów RR

Ograniczenie górnej częstości synchronizacji przedsionkowo-komorowej u chorej ze stymulatorem DDD spowodowane rejestracją potencjałów komorowych przez tor przedsionkowy

Przedstawiono przypadek chorej z wszczepionym stymulatorem DDD (Biotronik Actros D), u której po włączeniu funkcji dual demand nastąpiło nieoczekiwane obniżenie górnej częstości synchroni-zacji przedsionkowo-komorowej. To niekorzystne zachowanie stymulatora zostało spowodowane od-biorem przez tor przedsionkowy sygnału depolaryzacji komór (sensing of far field QRS complex)

Overview of APEX Project Results

The APEX mother-daughter project (Active Plasma EXperiments) was launched into an elliptical polar orbit (440–3,080 km) in December 1991. It consisted of the main Russian Interkosmos–25 (IK–25) satellite and the Czech MAGION–3 subsatellite, both with international scientific payloads. The mission used intensive modulated electron beam emissions and xenon plasma or neutral releases from the main satellite for studies of dynamic processes in the magnetosphere and upper ionosphere. Its main scientific objectives were to simulate an artificial aurora and to study optical and radio emissions from the aurora region, and to investigate the dynamics and relaxation of modulated electron and plasma jets, artificially injected into the ionospheric plasma. The experiments studied the Critical Ionization Velocity phenomenon and a diamagnetic cavity formation during the xenon releases, local and distant effects of the electron beam injection, spacecraft charging and potential balance, and plasma-wave interactions during the artificial emissions. Attempts were performed to utilize the modulated electron beam as an active transmitting antenna in the space. The theory of ballistic wave propagation across plasma barrier was tested in a joint active experiment with the Dushanbe ionospheric heater facility. In the paper, we give a short overview of the IK–25/MAGION–3 scientific instrumentation and methodology of experiments with artificial beam injections and we provide a review of the main APEX active experiments results, many of which have been published only in the Russian language so far. From a historical 25-years-long perspective, we try to put the results of the APEX experiments into the context of other active experiments in the space plasma