CAST: Recent results & future outlook

Çetin, Serkant Ali (Dogus Author) -- Ezer, Cemile (Dogus Author) -- Yıldız, Süleyman Cenk (Dogus Author) -- Conference full title: 6th Patras Workshop on Axions, WIMPs and WISPs, PATRAS 2010; Zurich; Switzerland; 5 July 2010 through 9 July 2010.The CAST (CERN Axion Solar Telescope) experiment is searching for solar axions by their conversion into photons inside the magnet pipes of an LHC dipole. The analysis of data taken so far has shown no signal above the background, thus implying an upper limit to the axion-photon coupling of ga < 0.85 × 10-10GeV -1 at 95% CL for ma < 0.02 eV/c2. Ongoing measurements, with the magnet bores filled with a buffer gas (3He), are improving the sensitivity of the experiment for higher axion masses towards 1 eV/c2. Recent results, new ideas for Axion-Like Particle (WISPs) searches with CAST in the near future and the prospects of a new generation Helioscope are presented here

CAST constraints on the axion-electron coupling

In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axiorecombination, the "BCA processes." Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling gae and axion-photon interaction strength ga using the CAST phase-I data (vacuum phase). For ma <~ 10 meV/c2 we find ga gae < 8.1 × 10−23 GeV−1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivity into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission

Charged particle timing at sub-25 picosecond precision : The PICOSEC detection concept

The PICOSEC detection concept consists in a “two-stage” Micromegas detector coupled to a Cherenkov radiator and equipped with a photocathode. A proof of concept has already been tested: a single-photoelectron response of 76 ps has been measured with a femtosecond UV laser at CEA/IRAMIS, while a time resolution of 24 ps with a mean yield of 10.4 photoelectrons has been measured for 150 GeV muons at the CERN SPS H4 secondary line. This work will present the main results of this prototype and the performance of the different detector configurations tested in 2016-18 beam campaigns: readouts (bulk, resistive, multipad) and photocathodes (metallic+CsI, pure metallic, diamond). Finally, the prospects for building a demonstrator based on PICOSEC detection concept for future experiments will be discussed. In particular, the scaling strategies for a large area coverage with a multichannel readout plane, the R&D on solid converters for building a robust photocathode and the different resistive configurations for a robust readout.Peer reviewe

Towards understanding global patterns of antimicrobial use and resistance in neonatal sepsis: insights from the NeoAMR network.

OBJECTIVE: To gain an understanding of the variation in available resources and clinical practices between neonatal units (NNUs) in the low-income and middle-income country (LMIC) setting to inform the design of an observational study on the burden of unit-level antimicrobial resistance (AMR). DESIGN: A web-based survey using a REDCap database was circulated to NNUs participating in the Neonatal AMR research network. The survey included questions about NNU funding structure, size, admission rates, access to supportive therapies, empirical antimicrobial guidelines and period prevalence of neonatal blood culture isolates and their resistance patterns. SETTING: 39 NNUs from 12 countries. PATIENTS: Any neonate admitted to one of the participating NNUs. INTERVENTIONS: This was an observational cohort study. RESULTS: The number of live births per unit ranged from 513 to 27 700 over the 12-month study period, with the number of neonatal cots ranging from 12 to 110. The proportion of preterm admissions <32 weeks ranged from 0% to 19%, and the majority of units (26/39, 66%) use Essential Medicines List 'Access' antimicrobials as their first-line treatment in neonatal sepsis. Cephalosporin resistance rates in Gram-negative isolates ranged from 26% to 84%, and carbapenem resistance rates ranged from 0% to 81%. Glycopeptide resistance rates among Gram-positive isolates ranged from 0% to 45%. CONCLUSION: AMR is already a significant issue in NNUs worldwide. The apparent burden of AMR in a given NNU in the LMIC setting can be influenced by a range of factors which will vary substantially between NNUs. These variations must be considered when designing interventions to improve neonatal mortality globally

Vertical transmission of hepatitis C virus in a hospital in southern Brazil Transmissão vertical do vírus da hepatite C em um hospital do sul do Brasil

BACKGROUND: There still are controversies concerning the vertical transmission of hepatitis C virus. AIM: To evaluate the prevalence of antibodies against hepatitis C virus in pregnant women, as well as the rate of vertical transmission of this virus. PATIENTS AND METHODS: Between August 1998 and November 1999, 1,090 consecutive pregnant women were screened for anti-hepatitis C virus; positive results were confirmed by the polymerase chain reaction assay. Patient's viral load was evaluated by the branched deoxyribonucleic acid assay. Hepatitis C virus genotype was identified by direct sequencing of the polymerase chain reaction amplification products. The same tests were performed in the children born from infected mothers at the 1st and 6th month of life. RESULTS: Of the 1,090 mothers surveyed, 29 were positive for anti-hepatitis C virus (prevalence of 2.66%). Twenty-five patients presented with hepatitis C virus RNA, with a median hepatitis C virus viral load of 3.132 ± 5.891 MEq/mL. Twenty-two patients (six human immunodeficiency virus-coinfected) were followed and gave birth to 23 children; 18 of them had blood samples tested at the 1st month of life, and 22, at the 6th month. Vertical transmission rate was 5.56%; it affected a girl who had hepatitis C virus RNA detectable only in the 1st month sample (41.570 MEq/mL). The mother who transmitted hepatitis C virus was coinfected with human immunodeficiency virus and presented with an hepatitis C virus viral load of 3.765 MEq/mL, with 100% homology with her daughter's hepatitis C virus genotype. CONCLUSION: These results suggest that the prevalence of hepatitis C virus infection in pregnant women should not be neglected, and early diagnosis of vertical transmission and the follow up of infected children should be emphasized.<br>RACIONAL: Ainda existem controvérsias em relação à transmissão vertical do vírus da hepatite C (VHC). OBJETIVO: Avaliar a prevalência dos anticorpos contra o VHC (anti-VHC) em mulheres grávidas, bem como a percentagem de transmissão vertical observada. PACIENTES E MÉTODOS: Entre agosto de 1998 e novembro de 1999, 1.090 mulheres grávidas consecutivas realizaram a determinação do anti-VHC. A confirmação do teste foi feita pela reação em cadeia da polimerase. A carga viral foi determinada pelo b-DNA e o genótipo por seqüenciamento. Os mesmos testes foram realizados no 1º e 6º mês de vida, nas crianças nascidas de mães infectadas. RESULTADOS: Das 1.090 mães estudadas, 29 apresentaram positividade para o anti-VHC (prevalência de 2,66%). Em 25 pacientes foi demonstrado o RNA do VHC, sendo que a carga viral média foi de 3,132 ± 5,891 MEq/mL. Vinte e duas pacientes (6 co-infectadas com o vírus da imunodeficiência humana) foram seguidas e deram à luz a 23 crianças, das quais 18 tiveram seu sangue testado no 1º mês e 22 no 6º mês. Foi observada transmissão vertical em 5,56% dos casos. Assim, em uma criança do sexo feminino foi detectado o RNA do VHC (41,570 MEq/mL). A mãe desta criança estava co-infectada pelo vírus da imunodeficiência humana e apresentava carga viral de 3,765 MEq/mL, com 100% de homologia no genótipo viral. CONCLUSÃO: Estes resultados sugerem que a prevalência da infecção pelo VHC em gestantes não deve ser negligenciada e que um diagnóstico precoce e o seguimento das crianças infectadas deve ser preconizado

Towards understanding global patterns of antimicrobial use and resistance in neonatal sepsis: Insights from the NeoAMR network

Objective To gain an understanding of the variation in available resources and clinical practices between neonatal units (NNUs) in the low-income and middle-income country (LMIC) setting to inform the design of an observational study on the burden of unit-level antimicrobial resistance (AMR). Design A web-based survey using a REDCap database was circulated to NNUs participating in the Neonatal AMR research network. The survey included questions about NNU funding structure, size, admission rates, access to supportive therapies, empirical antimicrobial guidelines and period prevalence of neonatal blood culture isolates and their resistance patterns. Setting 39 NNUs from 12 countries. Patients Any neonate admitted to one of the participating NNUs. Interventions This was an observational cohort study. Results The number of live births per unit ranged from 513 to 27 700 over the 12-month study period, with the number of neonatal cots ranging from 12 to 110. The proportion of preterm admissions &lt;32 weeks ranged from 0% to 19%, and the majority of units (26/39, 66%) use Essential Medicines List &apos;Access&apos; antimicrobials as their first-line treatment in neonatal sepsis. Cephalosporin resistance rates in Gram-negative isolates ranged from 26% to 84%, and carbapenem resistance rates ranged from 0% to 81%. Glycopeptide resistance rates among Gram-positive isolates ranged from 0% to 45%. Conclusion AMR is already a significant issue in NNUs worldwide. The apparent burden of AMR in a given NNU in the LMIC setting can be influenced by a range of factors which will vary substantially between NNUs. These variations must be considered when designing interventions to improve neonatal mortality globally. © Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ