Global disparities in SARS-CoV-2 genomic surveillance (preprint)

Genomic sequencing provides critical information to track the evolution and spread of SARS-CoV-2, optimize molecular tests, treatments and vaccines, and guide public health responses. To investigate the spatiotemporal heterogeneity in the global SARS-CoV-2 genomic surveillance, we estimated the impact of sequencing intensity and turnaround times (TAT) on variant detection in 167 countries. Most countries submit genomes >21 days after sample collection, and 77% of low and middle income countries sequenced <0.5% of their cases. We found that sequencing at least 0.5% of the cases, with a TAT <21 days, could be a benchmark for SARS-CoV-2 genomic surveillance efforts. Socioeconomic inequalities substantially impact our ability to quickly detect SARS-CoV-2 variants, and undermine the global pandemic preparedness. One-Sentence SummarySocioeconomic inequalities impacted the SARS-CoV-2 genomic surveillance, and undermined the global pandemic preparedness.

Travel Behaviour after the Pandemic: The Case of Bulgaria (preprint)

The paper analyses the travel intentions of tourists in the post-pandemic world. The sample includes 974 respondents from Bulgaria. The findings show that most of the respondents are ready to travel within two months after travel is allowed in the country. For their first trip, respondents will travel in the country, by their car and with their family. Hygiene, disinfection and reliable health system in a destination will be the leading factors in travellers’ decisions, according to the findings. Women and older respondents have higher health and safety preferences than do men and younger respondents.

Adaptation of the Main Actions in the National Employment Action Plan to COVID-19 (preprint)

This paper is the part of an extensive study which analyzes and examines the processes on the Bulgarian market that unfold in the emergency situation resulting from the COVID-19 pandemics. The focus is on the state of the labour market before the pandemic crisis and the subsequent changes in the current national employment plan in view of the challenges of the situation caused by COVID-19. It proposes measures and supports actions for restructuring the financial resource for adaptation of the plan to the new challenge to the labour market in Bulgaria.

uPTI: uniaxial permittivity tensor imaging of intrinsic density and anisotropy (preprint)

Biological architecture is intrinsically tensorial. The permittivity tensor (PT) of biological material reports the density, angular anisotropy, symmetry, and 3D orientation of biomolecules. High-resolution measurement of PT can enable quantitative and label-free analysis of organelle, cell, and tissue architecture, but remains challenging. We report uniaxial permittivity tensor imaging (uPTI), a label-free computational imaging method for volumetric measurement of PT with diffraction-limited resolution. uPTI encodes the components of PT into intensity modulations using oblique illumination and polarization-resolved imaging. The high-dimensional data is decoded with a vectorial image formation model and a multi-channel convex optimization, assuming that the molecular distribution in each voxel has uniaxial symmetry. We describe a modular implementation of uPTI that can be multiplexed with complementary imaging modalities. We report volumes of uPT in mouse brain tissue, SARS-CoV-2 infected cardiomyocytes, RSV infected A549 cells, H&E stained tissue sections, isotropic beads, and anisotropic glass targets. uPTI enabled volumetric imaging of the 3D orientation and symmetry of organelles, cells, and tissue components with higher spatio-angular resolution than current vectorial tomography, ptychography, and light-field microscopy methods. We provide an open source implementation of the image formation model and reconstruction algorithms.

The National Employment Plan in Bulgaria - Analysis and Opportunities for Change (preprint)

This paper is the part of an extensive study which analyzes and examines the processes on the Bulgarian market that unfold in the emergency situation resulting from the COVID-19 pandemics. The focus is on the state of the labour market before the pandemic crisis and the subsequent changes in the current national employment plan in view of the challenges of the situation caused by COVID-19. It proposes measures and supports actions for restructuring the financial resource for adaptation of the plan to the new challenge to the labour market in Bulgaria.

Heparin as an Anti-Inflammatory Agent (preprint)

ABSTRACT Timely control of the cytokine release syndrome (CRS) at the severe stage of COVID-19 is key to improving the treatment success and reducing the mortality rate. The inhibition of the activity of the two key cytokines, IFNγ and IL-6, can significantly reduce or even reverse the development of the cytokine storm. The objective of our investigations is to reveal the anti-inflammatory potential of heparin for prevention and suppression of the development of CRS in acute COVID-19 patients. The effect of low-molecular-weight heparin (LMWH) on IFNγ signalling inside the stimulated WISH cells was investigated by measuring its antiproliferative activity and the translocation of phosphorylated STAT1 in the nucleus. The mechanism of heparin binding to IFNγ and IL-6 and therefore inhibition of their activity was studied by means of extensive molecular-dynamics simulations. We find that LMWH binds with high affinity to IFNγ and is able to inhibit fully the interaction with its cellular receptor. It also influences the biological activity of IL-6 by binding to either IL-6 or IL-6/IL-6Rα thus preventing the formation of the IL-6/IL-6Rα/gp130 signaling complex. Our conclusion is that heparin is a potent anti-inflammatory agent that can be used in acute inflammatory conditions, due to its potential to inhibit both IFN γ and IL-6 signalling pathways. Based on our results and available clinical observations, we suggest the administration of LMWH to COVID-19 patients in the initial stages of the acute phase. The beginning of the treatment and the dosage should be based on a careful follow-up of the platelet count and the D-dimer, IL-6, IFN, T-cells, and B-cells levels.