Data on the duration of detectable Zika virus-specific IgM in infected persons are limited. Neutralizing antibody cross-reactivity occurs between Zika virus and related flaviviruses, but the degree ...to which this confounds diagnosis is uncertain. We tested serum specimens collected 12-19 months after illness onset from patients with confirmed Zika virus disease for Zika virus IgM and Zika virus and dengue virus neutralizing antibodies. Among 62 participants, 45 (73%) had detectable Zika virus IgM and 12 (19%) had an equivocal result. Although all patients tested had Zika virus neutralizing antibodies, 39 (63%) also had neutralizing antibodies against dengue virus; of those, 12 (19%) had <4-fold difference between Zika virus and dengue virus titers, and 5 (8%) had dengue virus titer >4-fold higher than Zika virus titer. Prolonged detection of IgM and neutralizing antibody cross-reactivity make it difficult to determine the timing of Zika virus infection and differentiate between related flaviviruses.
The impact of the manufacturing process on the radiation-induced degradation effects observed in CMOS image sensors (CISs) at the MGy total ionizing dose (TID) levels is investigated. Moreover, the ...vulnerability of the partially pinned PHDs at moderate-to-high TIDs is evaluated for the first time to our knowledge (PHD stands for "photodiode"). It is shown that the 3T-standard partially pinned PHD has the lowest dark current before irradiation, but its dark current increases to ~1 pA at 10 kGy(SiO 2 ). Beyond 10 kGy(SiO 2 ), the pixel functionality is lost. The comparison between several CIS technologies points out that the manufacturing process impacts the two main radiation-induced degradations: the threshold voltage shift of the readout chain MOSFETs and the dark current increase. For all the tested technologies, 1.8-V MOSFETs exhibit the lower threshold voltage shift, and the nMOSFETs are the most radiation tolerant. Among all the tested devices, 1.8-V sensors achieve the best dark current performance. Several radiation-hardening-by-design solutions are evaluated at the MGy level to improve further the understanding of CIS radiation hardening at extreme TID.
The potential of discrete and distributed fiber-based sensors exploiting the Rayleigh scattering signature of doped amorphous silica is investigated for the real time monitoring of molecular hydrogen ...(H2) detection. We showed that the impact of the refractive index changes induced by the H2 diffusion into the silica host matrix can be used to detect and quantify this gas presence through two approaches: first via the related fiber length variation and second through the observed spectral shift. Comparing the obtained results with H2 diffusion calculations, we can estimate the sensor sensitivity thresholds to be ∼1016 nmolecule cm−3 for the distributed measurements (spatial resolution better than 1 mm) and below ∼1019 nmolecule cm−3 for the discrete-one. The presented architecture of the sensor is well adapted to the monitoring of slowly evolving H2 concentrations such as the ones expected in nuclear waste repositories as the time response of the sensor remains limited by the diffusion of the gas within the optical fiber. These threshold values and time responses can be easily improved by optimizing the length, the composition and/or the geometry of the sensing fiber.
The difficulties encountered in the implementation of a temperature or strain sensor based on fiber Bragg grating (FBG) in a harsh radiative environment are introduced. We present the choices made to ...select both a radiation-resistant fiber in terms of transmission and also the grating inscription conditions necessary to write radiation tolerant FBGs in such fibers with a femtosecond laser. The radiation response of these gratings was also studied under radiation at dose up to 1 MGy. The comparison between Ge-free and Ge-doped fibers was highlighted.
We assessed IgM detection in Zika patients from the 2016 outbreak in Miami-Dade County, Florida, USA. Of those with positive or equivocal IgM after 12-19 months, 87% (26/30) had IgM 6 months later. ...In a survival analysis, ≈76% had IgM at 25 months. Zika virus IgM persists for years, complicating serologic diagnosis.
The response of optical frequency-domain reflectometry-based temperature sensors is here investigated in harsh environments (high temperature, high radiation dose) focusing the attention on the ...impact of the fiber coating on the sensor performances in such conditions. Our results demonstrate that the various coating types evolve differently under thermal treatment and/or radiations, resulting in a small (<;5%) change in the temperature coefficient of the sensor. The identified procedure, consisting of a prethermal treatment of the fiber at its maximum coating operating temperature, is here verified up to 150 °C for high-temperature acrylate and up to 300 °C for polyamide coating. This method allows a stabilization of the temperature coefficients. Finally, we show that radiation does not affect scattering phenomenon, temperature coefficients (C T s) remain identical within 1% fluctuations up to 10 MGy dose, and that permanent radiation-induced attenuation reached values stands for the development of high-spatial resolved distributed temperature for harsh environment associated with high temperature (up to 300 °C) and ionizing radiation up to the MGy dose level.
In the context of the rising of Monte Carlo transport calculations for any kind of application, AREVA recently improved its suite of engineering tools in order to produce efficient Monte Carlo ...workflow. Monte Carlo codes, such as MCNP or TRIPOLI, are recognized as reference codes to deal with a large range of radiation transport problems. However the inherent drawbacks of theses codes - laboring input file creation and long computation time - contrast with the maturity of the treatment of the physical phenomena. The goals of the recent AREVA developments were to reach similar efficiency as other mature engineering sciences such as finite elements analyses (e.g. structural or fluid dynamics). Among the main objectives, the creation of a graphical user interface offering CAD tools for geometry creation and other graphical features dedicated to the radiation field (source definition, tally definition) has been reached. The computations times are drastically reduced compared to few years ago thanks to the use of massive parallel runs, and above all, the implementation of hybrid variance reduction technics. From now engineering teams are capable to deliver much more prompt support to any nuclear projects dealing with reactors or fuel cycle facilities from conceptual phase to decommissioning.
We report the study of a radiation resistant single mode optical fiber doped with fluorine exposed to mixed neutron and γ-radiation up to 10 17 n/cm 2 fluence and 2 MGy dose to evaluate its ...performances when used as the sensing element of a distributed Optical Frequency Domain Reflectometry (OFDR). The use of complementary spectroscopic techniques highlights some differences between the responses of solely γ-radiation (10 MGy) or mixed neutron and y (10 17 n/cm 2+ 2 MGy) irradiated samples. Those differences are linked to the defect generation rather than to structural changes of the α-SiO 2 host matrix. We show that a modification of the refractive index of ~ 10 -5 is induced at the highest investigated neutron fluence. However, the feasibility of distributed temperature measurements along the irradiated fiber is demonstrated with an accuracy of 0.1 °C over a sensing length up to ~ 130 m with the tested OBR4600 interrogator. These results are very promising for the integration of OFDR sensors in mixed neutron and gamma radiation environments.
The rapid spread of Zika virus represents a threat to public health and demands significant preparation from hospitals and health care systems. Establishment of procedures for the identification of ...cases of Zika virus infection is a fundamental aspect of response planning. We describe the steps taken in the development and implementation of a protocol for the diagnosis and management of suspected cases of Zika virus infection in a large academic medical center. (Disaster Med Public Health Preparedness. 2017;11:256-258).
Zika virus (ZIKV) is causing an unprecedented epidemic linked to severe congenital abnormalities. In July 2016, mosquito-borne ZIKV transmission was reported in the continental United States; since ...then, hundreds of locally acquired infections have been reported in Florida. To gain insights into the timing, source, and likely route(s) of ZIKV introduction, we tracked the virus from its first detection in Florida by sequencing ZIKV genomes from infected patients and Aedes aegypti mosquitoes. We show that at least 4 introductions, but potentially as many as 40, contributed to the outbreak in Florida and that local transmission is likely to have started in the spring of 2016-several months before its initial detection. By analysing surveillance and genetic data, we show that ZIKV moved among transmission zones in Miami. Our analyses show that most introductions were linked to the Caribbean, a finding corroborated by the high incidence rates and traffic volumes from the region into the Miami area. Our study provides an understanding of how ZIKV initiates transmission in new regions.
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