RESUMEN
Corona virus disease 2019 (COVID-19) has been documented to have a spectrum of neuro-ophthalmic manifestations. However, bilateral non-arteritic anterior ischemic optic neuropathy (NAION) post-COVID-19 has not been reported in the literature. We studied the case of a 45-year-old male who presented to our outpatient department (OPD) with bilateral blurring of vision following an episode of COVID-19, 1 month back. Examination and investigations were conclusive of a bilateral NAION. The patient was given a trial of oral steroids. However, the vision loss could not be recovered. Thus, through this case report, we would like to highlight the importance of a close follow-up of patients following COVID-19 infection to detect any sequelae.
Asunto(s)
COVID-19 , Neuropatía Óptica Isquémica , Humanos , Masculino , Persona de Mediana Edad , Nervio Óptico , Neuropatía Óptica Isquémica/diagnóstico , Neuropatía Óptica Isquémica/etiología , SARS-CoV-2 , Trastornos de la VisiónRESUMEN
The advent of Accelerator Mass Spectrometer (AMS) enhanced the application of meteoric 10Be (half-life of 1.39 Ma) as a tracer for understanding earth surface processes on thousand to million-year time scales. However, for the majority of applications, an adequate understanding of the 10Be depositional flux is a prerequisite. A number of efforts have been made to understand both spatial and temporal variation of 10Be depositional flux. Yet, due to the limited globally distributed dataset and modulation of the 10Be signal by local processes, a significant offset is observed between model-derived and measured deposition rates of 10Be. In this study, an attempt has been made to determine the 10Be depositional flux from a marine sediment core from the central Indian Ocean chronologically constrained with the AMS radiocarbon dating and 10Be concentration measured with AMS. The 10Be depositional flux estimates using weak leaching method are found to be nearly 44% lower compared to the strong leaching method. The calculated 10Be depositional flux during the Holocene varies between 9.63 and 13.01 × 105 atoms/cm2/yr, which is 2-28% lower compared to the modeled depositional flux for the region. The difference observed in 10Be depositional flux could be due to the local processes (such as boundary scavenging, changing rate of sediment deposition at the location) affecting 10Be deposition into the sediment column or offset associated with the model estimations. The changes in 10Be depositional flux and the 10Be/9Be ratio have been reconstructed up to 43 ka. An increase in the 10Be/9Be ratio during 28 to 43 ka is observed due to the lower geomagnetic field intensity during the period. A high-resolution 10Be/9Be ratio reconstruction shows a peak at 41.2 ka, which can be attributed to the Laschamp event.
Asunto(s)
Sedimentos Geológicos , Océano ÍndicoRESUMEN
The first measurement of meteoric beryllium-10 (10Be) using Accelerator Mass Spectrometer (AMS) is reported from PRL-AURiS (Physical Research Laboratory-Accelerator Unit for Radioisotope Studies). Strategically, the meteoric 10Be dating method can date events as old as 10 Myr, and its accuracy while dating marine sediment cores has been well tested with magnetic methods. An attempt is made for a comparative study between radiocarbon (14C) and meteoric 10Be dating methods from a 6 m long sediment core collected from the equatorial Indian Ocean. The core was dated using both radiocarbon and meteoric 10Be and results showed remarkable similarity for both methods in terms of the sedimentation rate. A continuous age offset observed within 50 kyr could be due to a continuous influx of sediment with low 10Be content and that may have caused the meteoric 10Be ages to be younger. The sedimentation rate calculated by changing the 10Be depositional flux rate from 1.5 to 2.5 × 10-2 atoms.cm-2.s-1 shows large variation, indicating the choice of appropriate 10Be depositional flux rate for the region. Additionally, being the first meteoric beryllium-10 measurements using AURiS, we have also discussed and reported the laboratory protocols and efficiency based on repeat standard and blank measurements.
Asunto(s)
Monitoreo de Radiación , Contaminantes Radiactivos del Agua , Sedimentos Geológicos , Océano Índico , Contaminantes Radiactivos del Agua/análisisRESUMEN
PURPOSE: The purpose of this study was to report the analysis of reverse transcriptase polymerase chain reaction (RT-PCR) of nasopharyngeal (NP) samples of cornea donors dying because of causes unrelated to severe acute respiratory coronavirus (SARS-CoV-2). METHODS: A retrospective analysis of all cornea donors dying from causes other than SARS-CoV-2 between August 2020 and December 2020 was performed. Informed consent was obtained from the next of kin of the deceased for RT-PCR testing from NP swabs. Rapid antigen testing from all the deceased was performed before in situ cornea excision. In addition, NP samples in viral transport media for RT-PCR were also collected for SARS-CoV-2 analysis. Corneas were released from the eye bank only after a negative RT-PCR report. RESULT: One hundred eighteen corneas from 59 donors were obtained by the eye bank. Eleven donors (18.64%) were positive for SARS-CoV-2 on RT-PCR testing. Six of these 11 donors had a Ct value of E gene less than 25. CONCLUSIONS: NP samples of cornea donors dying due to causes other than coronavirus disease-19 were positive for SARS-CoV-2 on RT-PCR. This implicates that donors could be having asymptomatic/undetected coronavirus disease infection. We recommend adding the routine testing of NP samples of all cornea donors in the eye banking protocol in this ongoing SARS-CoV-2 pandemic.