Permanence of sown sward situated along the slopes of the central Balkan mountain

The state of mixed swards of red fescue, Kentucky bluegrass and bird's foot trefoil was studied. The experiment was situated along the slopes of the Central Balkan Mountain, during the period of the 1st to the 13th year of their creation. At a high degree of soil gleying, the low part of the slope, the dry matter yields were within the limits of 2.8 t/ha (1997, south-eastern exposure) up to 10.66 t/ha (1999, north-eastern exposure). At a low degree of soil gleying, high part of the slope, the dry matter yields were within the limits of 2.34 t/ha (1994, western exposure) up to 14.34 t/ha (1995, east exposure). The most prominent in productive terms for the period of the study are the variants at the east and south-eastern exposure, slightly gleyed soil. The participation of the sown species in the total forage yield is variable quantity. They reach (at their most) up to 96% in 1998, north exposure, slightly gleyed soils and up to 97% in 2000, north-east exposure, highly gleyed soils. Their share was small in 2004 (44%) and in 2006 (42%) on a western slope, highly eroded soils

Study of an Acrylamide-based Photopolymer for use as a Holographic Data Storage Medium

An acrylamide-based photopolymer formulated in the Centre for Industrial and Engineering Optics has been investigated with a view to further optimisation for holographic optical storage. Series of 15 to 30 gratings were angularly multiplexed in a volume of the photopolymer layers with different thickness at a spatial frequency of 1500 lines/mm. Since the photopolymer is a saturable material, an exposure scheduling method was used to exploit the entire dynamic range of the material and allow equal strength gratings to be recorded. From this investigation the photopolymer layer’s M/# was determined with regard to the recording geometry used. The temporal stability of photopolymer layers was studied in terms of diffraction efficiency and change of the reconstructed angle due to material shrinkage. In addition, the potential of the photopolymer as a holographic data storage medium was demonstrated by recording bit data-pages

Development of holographic optical elements for use in wound monitoring

Wounds that fail to heal impact the quality of life of 2.5 % of the total population. The costs of chronic wound care will reach $15–22 billion by 2024. These alarming statistics reveal the financial strain for both the medical industry and society. A solution can be found in compact and accessible sensors that offer real-time analysis of the wound site, facilitating continuous monitoring and immediate treatment, if required. Benefits of these sensors include reduction of cost and can extend the reach of healthcare to remote areas. The progression of a wound site can be closely monitored with holographic optical elements (HOEs) by real-time quantification of wound healing biomarkers, such as oxygen, temperature, pH and lactate. Fabrication of such wound monitoring sensors requires biocompatible, water-resistant photosensitive materials suitable for specific functionalisation with respect to wound analytes

Detection of Specific Antibodies to Arboviruses in Blood Sera of Persons Residing in Kindia Province, the Republic of Guinea

The aim of the work was to detect specific antibodies to West Nile, dengue, CCHF, and chikungunya viruses in blood sera of Guinean Kindia Province residents.Materials and methods. The obtained sera were analyzed in ELISA to discover IgG antibodies to abovementioned viruses.Results and conclusions. Detected were 267 (82 %) positive samples out of 326, containing immunoglobulins of G class to these arboviruses. The obtained data provide evidence for active circulation of dengue and West Nile fevers agents in this territory. Further studies of immune strata of the population, and possible carriers and vectors of arboviruses were demonstrated to be advisable for optimization of approaches to prophylactic (anti-epidemic) measures implementation

Detection of Crimean-Congo Hemorrhagic Fever Virus Markers in Samples of Ixodes Ticks Collected in the Territory of the Republic of Guinea

Objective of the study. This work was carried out to identify markers (antigen and RNA) of CrimeanCongo hemorrhagic fever (CCHF) virus in samples from ticks, collected in all landscape-geographical areas of Guinea: Lower, Middle, Upper and Forest, to obtain up-to-date data on the distribution of the pathogen in the country.Materials and methods. Total of 4276 specimens of 8 species of ticks collected in 2016–2019 in the territory of the Republic of Guinea were studied, which were compiled into 1406 samples. Ectoparasites were collected from livestock animals, dogs, and small mammals. Viral antigen was detected using enzyme immunoassay (ELISA). The presence of RNA of the CCHF virus was determined by reverse transcription polymerase chain reaction (RT-PCR).Results and discussion. As a result of the studies, the antigen of the CCHF virus was detected in 21 samples (1.5 %), and RNA – in 37 (2.6 %). All samples, in which the viral antigen was detected, contained RNA of the CCHF virus. Positive results were obtained in samples from all geographical areas of the country. The main vectors and reservoirs of the pathogen in Guinea are ticks of the species Rh. sanguineus, Rh. geigyi, Rh. annulatus and Am. variegatum. The data obtained confirm the previously available information on the possibility of the pathogen circulation in this region and determine the need for further study of the spread of the CCHF virus in the territory of the Republic of Guinea

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity.

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant

Genomic reconstruction of the SARS-CoV-2 epidemic in England.

The evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus leads to new variants that warrant timely epidemiological characterization. Here we use the dense genomic surveillance data generated by the COVID-19 Genomics UK Consortium to reconstruct the dynamics of 71 different lineages in each of 315 English local authorities between September 2020 and June 2021. This analysis reveals a series of subepidemics that peaked in early autumn 2020, followed by a jump in transmissibility of the B.1.1.7/Alpha lineage. The Alpha variant grew when other lineages declined during the second national lockdown and regionally tiered restrictions between November and December 2020. A third more stringent national lockdown suppressed the Alpha variant and eliminated nearly all other lineages in early 2021. Yet a series of variants (most of which contained the spike E484K mutation) defied these trends and persisted at moderately increasing proportions. However, by accounting for sustained introductions, we found that the transmissibility of these variants is unlikely to have exceeded the transmissibility of the Alpha variant. Finally, B.1.617.2/Delta was repeatedly introduced in England and grew rapidly in early summer 2021, constituting approximately 98% of sampled SARS-CoV-2 genomes on 26 June 2021

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Global dispersal and increasing frequency of the SARS-CoV-2 spike protein variant D614G are suggestive of a selective advantage but may also be due to a random founder effect. We investigate the hypothesis for positive selection of spike D614G in the United Kingdom using more than 25,000 whole genome SARS-CoV-2 sequences. Despite the availability of a large dataset, well represented by both spike 614 variants, not all approaches showed a conclusive signal of positive selection. Population genetic analysis indicates that 614G increases in frequency relative to 614D in a manner consistent with a selective advantage. We do not find any indication that patients infected with the spike 614G variant have higher COVID-19 mortality or clinical severity, but 614G is associated with higher viral load and younger age of patients. Significant differences in growth and size of 614G phylogenetic clusters indicate a need for continued study of this variant