The use of germicidal ultraviolet light, vaporised hydrogen peroxide and dry heat to decontaminate face masks and filtering respirators contaminated with a SARS-CoV-2 surrogate virus

peer reviewe

Standard Model with Partial Gauge Invariance

We argue that an exact gauge invariance may disable some generic features of the Standard Model which could otherwise manifest themselves at high energies. One of them might be related to the spontaneous Lorentz invariance violation (SLIV) which could provide an alternative dynamical approach to QED and Yang-Mills theories with photon and non-Abelian gauge fields appearing as massless Nambu-Goldstone bosons. To see some key features of the new physics expected we propose partial rather than exact gauge invariance in an extended SM framework. This principle applied, in some minimal form, to the weak hypercharge gauge field B_{mu} and its interactions leads to SLIV with B field components appearing as the massless Nambu-Goldstone modes, and provides a number of distinctive Lorentz beaking effects. Being naturally suppressed at low energies they may become detectable in high energy physics and astrophysics. Some of the most interesting SLIV processes are considered in significant detail.Comment: 32 pages, extended version, to appear in Eur.Phys.J.

Heterogeneous alkenylation of aromatics under oxygen

A novel heterogeneous Pd/polymer catalyst containing co-catalytic functional groups catalyses the direct alkenylation of anisole with ethyl trans-cinnamate under oxygen. The properties of the polymeric catalyst were compared to other immobilised catalysts. The activity of the polymeric catalyst typically increased with temperature and oxygen pressure exhibiting the optimal activity up to 100 TON at 383 K under 1.2 MPa of O-2. The most abundant product was 3-(p-methoxyphenyl)-3-phenylpropanoate (approximate to 45%). The reaction selectivity was practically independent of the conditions. Split-tests and AAS measurements confirm heterogeneous character of the catalyst

Handling Liveness Properties in (ω-)Regular Model Checking

peer reviewedSince the topic emerged several years ago, work on regular model checking has mostly been devoted to the verification of state reachability and safety properties. Though it was known that liveness properties could also be checked within this framework, little has been done about working out the corresponding details, and experimentally evaluating the approach. This paper addresses these issues in the context of regular model checking based on the encoding of states by finite or infinite words. It works out the exact constructions to be used in both cases, and solves the problem resulting from the fact that infinite computations of unbounded configurations might never contain the same configuration twice, thus making cycle detection problematic. Several experiments showing the applicability of the approach were successfully conducted

Uptake of Protic Electrolytes by Polybenzimidazole - Type Polymers - Adsorption Isotherm and Electrolyte/Polymer Interactions

Polybenzimidazole (PBI) membranes doped with phosphoric acid are used as proton-conducting membrane in high-temperature polymer electrolyte fuel cells. There is no general model for the thermodynamics of the absorption process over the whole accessible doping range for all published data. The interactions between H3PO4 and polymer chains, the polycondensation equilibria of H3PO4 and the implications on proton conductivity are still largely unknown. In this study, we demonstrate that the uptake of a protic electrolyte by a polymer with basic moieties, i.e. a PBI-type polymer, can be described satisfactorily with a BET-like absorption isotherm. The absorption equilibria of the uptake process are analysed using literature data on the H3PO4, H2SO4 and HClO4 uptake of non-crosslinked m-PBI and AB-PBI as well as using our own investigations on the H3PO4 uptake of a commercial crosslinked PBI derivative, Fumapem AM-55. In addition to the thermodynamic data of the absorption process, Raman data on m-PBI taken from the literature and our own Raman investigations on Fumapem AM-55 are taken into account. It is possible to correlate domains in the absorption isotherms with specific features in the Raman spectra. Two stages for the uptake of a protic electrolyte can be distinguished: (i) the protonation of the polymer chains and thus coulombic interactions with the electrolyte anions, (ii) the formation of H bonds directly with the chains and with electrolyte molecules that are still absorbed

Inductively coupled plasma mass spectrometry hyphenated to capillary gas chromatography as a detection system for the speciation analysis of organolead compounds in environmental water

The application of an inductively coupled plasma mass spectrometry detection system to the speciation of organolead compounds in environmental waters is described. Derivatization was carried out by propylation with a Grignard reagent after extraction of the organolead compounds into hexane as their diethyldithiocarbamate complexes. This was followed by separation and detection with capillary gas chromatography and inductively coupled plasma mass spectrometry. Detection limits ranging from 10 fg (0.05 ng l(-1)) (as Pb) for trimethyllead to 16 fg (0.08 ng l(-1)) (as Ph) for diethyllead were achieved. The accuracy of the method was confirmed by additional analysis of the water samples with capillary gas chromatography coupled to microwave-induced plasma atomic emission spectrometry and by the analysis of a reference material from the Standards, Measurements & Testing Programme of the European Union

Inductively coupled plasma mass spectrometry hyphenated to capillary gas chromatography as a detection system for the speciation analysis of organolead compounds in environmental waters

The application of an inductively coupled plasma mass spectrometry detection system to the speciation of organolead compounds in environmental waters is described. Derivatization was carried out by propylation with a Grignard reagent after extraction of the organolead compounds into hexane as their diethyldithiocarbamate complexes. This was followed by separation and detection with capillary gas chromatography and inductively coupled plasma mass spectrometry. Detection limits ranging from 10 fg (0.05 ng l(-1)) (as Pb) for trimethyllead to 16 fg (0.08 ng l(-1)) (as Ph) for diethyllead were achieved. The accuracy of the method was confirmed by additional analysis of the water samples with capillary gas chromatography coupled to microwave-induced plasma atomic emission spectrometry and by the analysis of a reference material from the Standards, Measurements & Testing Programme of the European Union

"Don, doff, discard" to "don, doff, decontaminate"-FFR and mask integrity and inactivation of a SARS-CoV-2 surrogate and a norovirus following multiple vaporised hydrogen peroxide-, ultraviolet germicidal irradiation-, and dry heat decontaminations.

BackgroundAs the SARS-CoV-2 pandemic accelerates, the supply of personal protective equipment remains under strain. To combat shortages, re-use of surgical masks and filtering facepiece respirators has been recommended. Prior decontamination is paramount to the re-use of these typically single-use only items and, without compromising their integrity, must guarantee inactivation of SARS-CoV-2 and other contaminating pathogens.AimWe provide information on the effect of time-dependent passive decontamination (infectivity loss over time during room temperature storage in a breathable bag) and evaluate inactivation of a SARS-CoV-2 surrogate and a non-enveloped model virus as well as mask and respirator integrity following active multiple-cycle vaporised hydrogen peroxide (VHP), ultraviolet germicidal irradiation (UVGI), and dry heat (DH) decontamination.MethodsMasks and respirators, inoculated with infectious porcine respiratory coronavirus or murine norovirus, were submitted to passive decontamination or single or multiple active decontamination cycles; viruses were recovered from sample materials and viral titres were measured via TCID50 assay. In parallel, filtration efficiency tests and breathability tests were performed according to EN standard 14683 and NIOSH regulations.Results and discussionInfectious porcine respiratory coronavirus and murine norovirus remained detectable on masks and respirators up to five and seven days of passive decontamination. Single and multiple cycles of VHP-, UVGI-, and DH were shown to not adversely affect bacterial filtration efficiency of masks. Single- and multiple UVGI did not adversely affect respirator filtration efficiency, while VHP and DH induced a decrease in filtration efficiency after one or three decontamination cycles. Multiple cycles of VHP-, UVGI-, and DH slightly decreased airflow resistance of masks but did not adversely affect respirator breathability. VHP and UVGI efficiently inactivated both viruses after five, DH after three, decontamination cycles, permitting demonstration of a loss of infectivity by more than three orders of magnitude. This multi-disciplinal approach provides important information on how often a given PPE item may be safely reused