Study of electron transmission through a metallic capillary

In this work we study the transmission of charged particles through a single cylindrically shaped metallic capillary of microscopic dimensions with a large aspect ratio. We used electrons as projectiles. Our results suggest the existence of guiding of the electron beam by a metallic capillary.29th International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC), Jul 22-28, 2015, Toledo, Spai

Contextualising adverse events of special interest to characterise the baseline incidence rates in 24 million patients with COVID-19 across 26 databases: a multinational retrospective cohort study

BACKGROUND: Adverse events of special interest (AESIs) were pre-specified to be monitored for the COVID-19 vaccines. Some AESIs are not only associated with the vaccines, but with COVID-19. Our aim was to characterise the incidence rates of AESIs following SARS-CoV-2 infection in patients and compare these to historical rates in the general population. METHODS: A multi-national cohort study with data from primary care, electronic health records, and insurance claims mapped to a common data model. This study's evidence was collected between Jan 1, 2017 and the conclusion of each database (which ranged from Jul 2020 to May 2022). The 16 pre-specified prevalent AESIs were: acute myocardial infarction, anaphylaxis, appendicitis, Bell's palsy, deep vein thrombosis, disseminated intravascular coagulation, encephalomyelitis, Guillain- Barré syndrome, haemorrhagic stroke, non-haemorrhagic stroke, immune thrombocytopenia, myocarditis/pericarditis, narcolepsy, pulmonary embolism, transverse myelitis, and thrombosis with thrombocytopenia. Age-sex standardised incidence rate ratios (SIR) were estimated to compare post-COVID-19 to pre-pandemic rates in each of the databases. FINDINGS: Substantial heterogeneity by age was seen for AESI rates, with some clearly increasing with age but others following the opposite trend. Similarly, differences were also observed across databases for same health outcome and age-sex strata. All studied AESIs appeared consistently more common in the post-COVID-19 compared to the historical cohorts, with related meta-analytic SIRs ranging from 1.32 (1.05 to 1.66) for narcolepsy to 11.70 (10.10 to 13.70) for pulmonary embolism. INTERPRETATION: Our findings suggest all AESIs are more common after COVID-19 than in the general population. Thromboembolic events were particularly common, and over 10-fold more so. More research is needed to contextualise post-COVID-19 complications in the longer term. FUNDING: None

Absolute cross sections for elastic electron scattering from 3-hydroxytetrahydrofuran

The results of measurements and calculations of absolute cross sections for elastic electron scattering from the 3-hydroxytetrahydrofuran (3hTHF) (C 4H8O2) molecule are reported. The measurements were performed using a crossed beam experimental setup, for an incident electron energy range of 40-300eV and an overall scattering angle range of 10°-110°. Relative differential cross sections (DCSs) were measured both as a function of the angle and the incident energy and the absolute DCSs were determined using the relative flow technique. The calculations of molecular cross sections are based on a corrected form of the independent-atom method, known as the screen corrected additivity rule (SCAR) procedure and using an improved quasifree absorption model. Additional calculations are also done to investigate the influence of rotational excitations and low-angular behavior of SCAR DCSs. The calculated dataset includes differential, integral and total cross sections in the energy range from 5eV to 10000eV. The present results are discussed regarding the most recent low-energy elastic DCSs for 3hTHF (Vizcaino et al 2008 New J. Phys. 10 053002), as well as the recent DCSs for molecules of similar structure (tetrahydrofuran and tetrahydrofurfuryl alcohol). © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.This work has been partially supported by the Ministry of Science and Technological Development of Republic of Serbia under project 141011 and the Spanish Ministerio de Educacion y Ciencia (project BFM2003-04648/FISI) and motivated by research within COST Actions P9 ‘Radiation Damage in Biomolecular Systems’ and CM0601 ‘Electron Controlled Chemical Lithography (ECCL)’Peer Reviewe

Optical and Electron Spectrometry of Molecules of Biological Interest

Optical absorption and emission spectroscopy together with low energy electron interaction (elastic scattering, excitation, ionization, resonances) with biologically relevant molecules (nitrogen, oxygen, water, alcohols, tetrahydrofuran, tetrahydrofurfuril alcohol, 3-hydroxytetrahydrofuran, pyrimidine, glycine, alanine) are studied in order to understand radiation damage and to investigate the presence of pollutants in the atmosphere. Versatile high resolution electron spectrometers are used in the present study of electron-molecule interactions. Energy loss spectra were recorded for these molecules in order to identify electronic transitions from ground state to both allowed and optically forbidden states. Optical emission spectra have been recorded from gas discharge processes by low resolution optical spectrometer (Ocean Optics 2000). Also, electronic spectra were compared with high resolution synchrotron photoabsorption spectra where these spectra had been available. Experimental methods of absorption-based laser spectroscopy were reviewed being of the most widely used analytical tools for detection of a specific molecule and quantitative measurements, based on the Beer-Lambert absorption law

Optical and Electron Spectrometry of Molecules of Biological Interest

Optical absorption and emission spectroscopy together with low energy electron interaction (elastic scattering, excitation, ionization, resonances) with biologically relevant molecules (nitrogen, oxygen, water, alcohols, tetrahydrofuran, tetrahydrofurfuril alcohol, 3-hydroxytetrahydrofuran, pyrimidine, glycine, alanine) are studied in order to understand radiation damage and to investigate the presence of pollutants in the atmosphere. Versatile high resolution electron spectrometers are used in the present study of electron-molecule interactions. Energy loss spectra were recorded for these molecules in order to identify electronic transitions from ground state to both allowed and optically forbidden states. Optical emission spectra have been recorded from gas discharge processes by low resolution optical spectrometer (Ocean Optics 2000). Also, electronic spectra were compared with high resolution synchrotron photoabsorption spectra where these spectra had been available. Experimental methods of absorption-based laser spectroscopy were reviewed being of the most widely used analytical tools for detection of a specific molecule and quantitative measurements, based on the Beer-Lambert absorption law

Study of electron transmission through a platinum tube

We have measured 200 eV electron transmission through a single platinum tube of a diameter of 3.3 mm. We find that the transmission of electrons can be detected even at large tilt angles, where the tube is not transparent geometrically. The transmission drops down exponentially with increasing the tilt angle. The energy spectrum of detected electrons behind the tube contain contributions at lower energies due to both inelastic scattering and secondary electron emission. The spectrum is qualitatively in good agreement with the calculations performed for the flat Pt surface in order to understand and model the electron interaction processes that define the transmission and the energy spectrum at the exit. (C) 2014 Elsevier B.V. All rights reserved

Electron impact excitation of methane: determination of appearance energies for dissociation products

In this work, we present an experimental study of dissociative excitation of CH₄ utilizing a crossed electron molecular beam experiment. Methane was excited by nearly monochromatic electrons generated by a trochoidal electron monochromator. The dissociative products were identified on the basis of the emission spectra in the ultraviolet–visible (UV/VIS) spectral range. The excitation functions were recorded as the function of the electron energy for different emission bands of the fragments (Balmer series for H: n = 3,4...9→2, and moreover, CH: A²Δ→X²Π, CH: B²Σ⁻→ X²Π, CH: C²Σ⁺→ X²Π, CH⁺: B¹Δ→ A¹Π, and CI: 2p3s ¹Po₁→2p² ¹S₀). From the experimental data we have determined the threshold energies for excitation of particular fragments. Present experimental results indicate that the threshold energies for some dissociative excitation channels could be lower by ~1–2 eV in comparison to earlier studies and indicate that different dissociative processes may be operative at the threshold than assumed in the former studies