Electromagnetic interference shielding and radiation absorption in thin polypyrrole films

Results of permittivity measurements, electromagnetic interference shielding effectiveness, and heat generation due to microwave absorption in conducting polymer coated textiles are reported and discussed. The intrinsically conducting polymer, polypyrrole, doped with anthraquinone-2-sulfonic acid (AQSA) or para-toluene-2-sulfonic acid (pTSA) was applied on textile substrates and the resulting materials were investigated in the frequency range 1&ndash;18 GHz. The 0.54 mm thick conducting textile/polypyrrole composites absorbed up to 49.5% of the incident 30&ndash;35 W microwave radiation. A thermography station was used to monitor the temperature of these composites during the irradiation process, where absorption was confirmed via visible heat losses. Samples with lower conductivity showed larger temperature increases caused by microwave absorption compared to samples with higher conductivity. A sample with an average sheet resistivity of 150 &Omega;/sq. showed a maximum temperature increase of 5.27 &deg;C, whilst a sample with a lower resistivity (105 &Omega;/sq.) rose by 3.85 &deg;C.<br /

Electromagnetic shielding properties of polypyrrole/polyester composites in the 1–18 GHz frequency range

The dielectric characteristics of conducting polymer-coated textiles in the frequency range 1&ndash;18 GHz were investigated using a non-contact, non-destructive free space technique. Polypyrrole coatings were applied by solution polymerization on fabric substrates using a range of concentrations of para-toluene-2-sulfonic acid (pTSA) as dopant and ferric chloride as oxidant. The conducting polymer coatings exhibited dispersive permittivity behaviour with a decrease in real and imaginary components of complex permittivity as frequency increased in the range tested. Both the permittivity and the loss factor were affected by the polymerization time of the conductive coating. It was found that the total shielding efficiency of these conductive fabrics is significant at short polymerization times and increases to values exceeding 80% with longer polymerization times. The reflection contribution to electromagnetic shielding also increases with polymerization time.<br /

Dielectric characterization of conducting textiles using free space transmission measurements: accuracy and methods for improvement

The dielectric behaviour of in-situ polymerized thin polypyrrole (PPy) films on synthetic textile substrates were obtained in the 1&ndash;18 GHz region using free space transmission and reflection methods. The PPy/para-toluene-2-sulphonic acid (pTSA) coated fabrics exhibited an absorption dominated total shielding effectiveness (SE) of up to &minus;7.34 dB, which corresponds to more than 80% of incident radiation. The permittivity response is significantly influenced by the changes in ambient conditions, sample size and diffraction around the sample. Mathematical diffraction removal, time-gating tools and high gain horns were utilized to improve the permittivity response. A narrow time-gate of 0.15 ns produced accurate response for frequencies above 6.7 GHz and the high gain horns further improved the response in the 7.5&ndash;18 GHz range. Errors between calculated and measured values of reflection were most commonly within 2%, indicating good accuracy of the method.<br /

Minimal Informationally Complete Measurements for Pure States

We consider measurements, described by a positive-operator-valued measure (POVM), whose outcome probabilities determine an arbitrary pure state of a D-dimensional quantum system. We call such a measurement a pure-state informationally complete (PSI-complete) POVM. We show that a measurement with 2D-1 outcomes cannot be PSI-complete, and then we construct a POVM with 2D outcomes that suffices, thus showing that a minimal PSI-complete POVM has 2D outcomes. We also consider PSI-complete POVMs that have only rank-one POVM elements and construct an example with 3D-2 outcomes, which is a generalization of the tetrahedral measurement for a qubit. The question of the minimal number of elements in a rank-one PSI-complete POVM is left open.Comment: 2 figures, submitted for the Asher Peres festschrif

Novel method for combined linkage and genome-wide association analysis finds evidence of distinct genetic architecture for two subtypes of autism

The Autism Genome Project has assembled two large datasets originally designed for linkage analysis and genome-wide association analysis, respectively: 1,069 multiplex families genotyped on the Affymetrix 10 K platform, and 1,129 autism trios genotyped on the Illumina 1 M platform. We set out to exploit this unique pair of resources by analyzing the combined data with a novel statistical method, based on the PPL statistical framework, simultaneously searching for linkage and association to loci involved in autism spectrum disorders (ASD). Our analysis also allowed for potential differences in genetic architecture for ASD in the presence or absence of lower IQ, an important clinical indicator of ASD subtypes. We found strong evidence of multiple linked loci; however, association evidence implicating specific genes was low even under the linkage peaks. Distinct loci were found in the lower IQ families, and these families showed stronger and more numerous linkage peaks, while the normal IQ group yielded the strongest association evidence. It appears that presence/absence of lower IQ (LIQ) demarcates more genetically homogeneous subgroups of ASD patients, with not just different sets of loci acting in the two groups, but possibly distinct genetic architecture between them, such that the LIQ group involves more major gene effects (amenable to linkage mapping), while the normal IQ group potentially involves more common alleles with lower penetrances. The possibility of distinct genetic architecture across subtypes of ASD has implications for further research and perhaps for research approaches to other complex disorders as well

Free space permittivity and permeability measurements at microwave frequencies

Abstract not availabl

The influence of polymerization time and dopant concentration on the absorption of microwave radiation in conducting polypyrrole coated textiles

Temperature changes in conducting polypyrrole/para-toluene-2-sulphonic acid (PPy/pTSA) coated nylon textiles due to microwave absorption in the 8&ndash;9 GHz and 15&ndash;16 GHz frequency ranges were obtained by a thermography station during simultaneous irradiation of the samples. The temperature values are compared and related to the amounts of reflection, transmission and absorption obtained with a non-contact free space transmission technique, indicating a relationship between microwave absorption and temperature increase. Non-conductive samples showed no temperature increase upon irradiation irrespective of frequency range. The maximum temperature difference of around 4 &deg;C in the conducting fabrics relative to ambient temperature was observed in samples having 48% absorption and 26.5 &plusmn; 4% reflection. Samples polymerized for 60 or 120 min with a dopant concentration of 0.018 mol/l or polymerized for 180 min with a dopant concentration of 0.009 mol/l yielded optimum absorption levels. As the surface resistivity decreased and the reflection levels increased, the temperature increase upon irradiation reduced.<br /

Cardiac assessment and inflammatory markers in children with paediatric inflammatory multisystem syndrome temporally associated with SARS-CoV2 (PIMS-TS) treated with methylprednisolone versus intravenous immunoglobulins: 6-month follow-up outcomes of the randomised controlled Swissped RECOVERY trialResearch in context

Summary: Background: Previous findings from the Swissped RECOVERY trial showed that patients with Pediatric Inflammatory Multisystem Syndrome–Temporally Associated with SARS-CoV-2 (PIMS-TS) who were randomly assigned to intravenous immunoglobulins or methylprednisolone have a comparable length of hospital stay. Here, we report the 6-month follow-up outcomes of cardiac pathologies and normalisation of clinical or laboratory signs of inflammation from this study population. Methods: This pre-planned follow-up of patients with PIMS-TS included the Swissped RECOVERY Trial reports on the 6-month outcomes of the cohort after randomisation, with a focus on cardiac, haematological, and biochemical findings. The trial was an investigator-initiated randomised multicentre open-label two-arm trial in children and adolescents hospitalised with PIMS-TS at ten hospitals in Switzerland. Cardiological assessments and laboratory analyses were prospectively collected in the intention-to-treat analysis on pre-defined intervals after hospital discharge. Differences between randomised arms were investigated using Chi-square test for categorical and Wilcoxon test for continuous variables. The trial is registered with the Swiss National Clinical Trials Portal (SNCTP000004720) and ClinicalTrials.gov (NCT04826588). Findings: Between May 21, 2021 and April 15, 2022, 75 patients with a median age of 9.1 years (IQR 6.2–12.2) were included in the intention-to-treat population (37 in the methylprednisolone group and 38 in the intravenous immunoglobulin group). During follow-up, the incidence of abnormal left ventricular systolic function, coronary artery aneurysms (CAA), and other signs of inflammation were comparable in both groups. However, we detected cardiac abnormalities with low incidence and a mild degree grade of pathology. CAAs were observed in 2/38 children (5.3%) in the IVIG group and 1/37 children (2.7%) in the methylprednisolone group at 6-month follow-up (difference proportion 0.75; 95% confidence interval (CI) −0.05 to 1.0; p = 0.39). Interpretation: Methylprednisolone alone may be an acceptable first-line treatment as left ventricular systolic dysfunction and clinical/laboratory evidence for inflammation quickly resolved in all children. However, our findings need further confirmation through larger studies as our sample size is likely to be of insufficient power to address rare clinically relevant adverse outcomes. Funding: NOMIS, Vontobel, and Gaydoul Foundation