Diagnostic du Covid-19 en milieu ambulatoire [COVID-19 Diagnosis]

The need to curb the circulation of SARS-CoV-2 virus in the community and to diagnose those at risk of developing complications implies that an appropriate test should be chosen according to the epidemiological and clinical context. Rapid antigen tests, either nasopharyngeal or nasal, have the advantage of reflecting contagiousness better than PCR and giving an immediate result, reason why they are used as first-line for community diagnosis and screening. A rapid test allows immediate management of outpatients and does not falsely attribute the current acute episode to a previous SARS-CoV-2 infection. PCR, whether nasopharyngeal or buccosalivary, is useful for epidemiological surveillance, including that of new variants, as well as identification of severe COVID in the post-infectious phase

Dépistage de l’infection à SARS-CoV-2 chez les voyageurs - Quelle approche pour évaluer le risque de transmis [SARS-CoV-2 screening in travelers: what approach to assess transmission risk ?]

Before a trip, a screening for SARS-CoV-2 infection by RT-PCR is often required and raises the problem of detection of residual viral RNA at distance from the acute infection (post-Covid). At the University Hospital of Geneva, we developed an expertise to distinguish acute from post-Covid infections. Between October and December 2020, 30% of the people tested positive were able to travel because the result corresponded to post-Covid and 65% were put in isolation because of an acute infection with a risk of transmission. To overcome the detection of residual viral RNA by RT-PCR, a rapid antigenic test would be an interesting and less expensive alternative. It could also be performed a few hours before departure

HIGH RESOLUTION MULTICHANNEL XUV SPECTROMETER WITH A 3-PICOSECOND TIME-RESOLUTION FOR LASER-PRODUCED PLASMAS DIAGNOSTICS

Nous décrivons la réalisation d'un nouveau spectrographe XUV à résolution temporelle dont les performances espérées sont une résolution spectrale de 0.1 Å et temporelle de 3 ps . Cet instrument est constitué d'un spectromètre Schwob-Fraenkel modifié, couplé à une nouvelle caméra électronique à balayage de fente ultra-rapide.A new XUV spectrometer designed to have a time-resolution of 3 ps and a spectral resolution of 0.1 Å is described. It is basically a modified version of a Schwob-Fraenkel spectrometer, which is coupled to a new ultrafast electronic streak camera

Performance of RT-PCR on Saliva Specimens Compared With Nasopharyngeal Swabs for the Detection of SARS-CoV-2 in Children: A Prospective Comparative Clinical Trial.

Saliva reverse transcriptase-Polymerase chain reaction (RT-PCR) is an attractive alternative for the detection of severe acute respiratory syndrome coronavirus 2 in adults with less known in children. Children with coronavirus disease 2019 symptoms were prospectively enrolled in a 1-month comparative clinical trial of saliva and nasopharyngeal (NP) RT-PCR. Detection rates and sensitivities of saliva and NP RT-PCR were compared as well as discordant NP and saliva RT-PCR findings including viral loads (VLs). Of 405 patients enrolled, 397 patients had 2 tests performed. Mean age was 12.7 years (range, 1.2-17.9). Sensitivity of saliva was 85.2% (95% confidence interval: 78.2%-92.1%) when using NP as the standard; sensitivity of NP was 94.5% (89.8%-99.2%) when saliva was considered as the standard. For a NP RT-PCR VL threshold of ≥103 and ≥104 copies/mL, sensitivity of saliva increases to 88.7% and 95.2%, respectively. Sensitivity of saliva and NP swabs was, respectively, 89.5% and 95.3% in patient with symptoms less than 4 days (P = 0.249) and 70.0% and 95.0% in those with symptoms ≥4-7 days (P = 0.096). The 15 patients who had an isolated positive NP RT-PCR were younger (P = 0.034), had lower NP VL (median 5.6 × 103 vs. 3.9 × 107, P < 0.001), and could not drool saliva at the end of the sampling (P = 0.002). VLs were lower with saliva than with NP RT-PCR (median 8.7 cp/mL × 104; interquartile range 1.2 × 104-5.2 × 105; vs. median 4.0 × 107 cp/mL; interquartile range, 8.6 × 105-1 × 108; P < 0.001). While RT-PCR testing on saliva performed more poorly in younger children and likely after longer duration of symptoms, saliva remains an attractive alternative to NP swabs in children

Crescimento, parâmetros biofísicos e aspectos anatômicos de plantas jovens de seringueira inoculadas com fungo micorrízico arbuscular Glomus clarum Growth, biophysical parameters and anatomical aspects of young rubber tree plants inoculated with arbuscular mycorrhizal fungi Glomus clarum

Fungos micorrízicos são reconhecidamente benéficos quando em associação às plantas por favorecerem seu crescimento e desenvolvimento. Apesar de pouco comum para a seringueira, a inoculação artificial de fungos micorrízicos arbusculares (FMAs) tem se mostrado uma alternativa para a redução no uso de fertilizantes e pesticidas nas culturas, bem como para a formação de mudas, visando obtenção de porta-enxertos precoces e bem nutridos. O estudo objetivou avaliar o efeito da inoculação do FMA Glomus clarum no crescimento e características biofísicas e anatômicas de plantas jovens de seringueira. Os tratamentos consistiram de plantas inoculadas com o fungo Glomus clarum adubadas com 50 ppm de fósforo (mic+50P), plantas não inoculadas adubadas com 50 ppm de fósforo (s/mic+50P) e plantas não inoculadas adubadas com 500 ppm de fósforo (s/mic+500P). Constatou-se que as plantas micorrizadas apresentaram altura e diâmetro dos caules, matéria seca da parte aérea, densidade estomática e área foliar, semelhantes às plantas s/mic+500P. Maior acúmulo de matéria seca de raiz, maior taxa de transpiração, menor resistência estomática e menor temperatura foliar foram observadas para as plantas micorrizadas. As análises anatômicas das raízes evidenciam a ocorrência de alterações no tecido vascular, com aumento no número de pólos de xilema das raízes das plantas micorrizadas.<br>Mycorrhizal fungi are beneficial when associated with plants because they favor growth and develop. Although infrequent, artificial inoculation of arbuscular mycorrhizal fungi (AMF) has become an alternative to reduce the use of fertilizers and pesticides in crops, as well as for the formation of seedlings, to obtain precocious and well fed rootstocks. The objective of the study was to evaluate the effect of inoculation of AMF Glomus clarum on growth and biophysical and anatomical characteristics of young rubber trees. The treatments consist of plants inoculated with the fungus Glomus clarum and fertilized with 50 ppm of phosphorus (mic+50P), non-inoculated plants fertilized with 50 ppm of phosphorus (s/mic+50P) and non-inoculated plants fertilized with 500 ppm of phosphorus (s/mic+500P). The mycorrhizal plants showed height and stem diameter, dry matter accumulation of the aerial part, stomatal density and leaf area similar to the plants s/mic+500P. Greater accumulation of dry matter in the roots, higher transpiration rate, less stomatal resistance and lower leaf temperature were reported for the mycorrhizal plants. The anatomical analyses of the roots showed alterations in the vascular tissue, with increase in the number of xylem poles in the mycorrhizal plant roots