Dried Blood Spots as a Clinical Samples for Laboratory Diagnosis and Surveillance of Vaccine-Preventable Diseases in Bulgaria

In recent years the dried blood spots (DBS) had new and innovative applications in medicine, neonatology, virology and microbiology. This study aimed to evaluation of the frequency of detection of viral IgM/IgG markers in dried blood spots and introducing an easy-to-implement protocol for serum extraction in measles, mumps and rubella surveillance. The total 204 clinical samples (102 serum samples and 102 dried blood spots) collected from 102 patients were included. All specimens were tested for presence of specific viral markers (IgM and IgG antibodies) by a commercial indirect enzyme-linked immunosorbent assay (ELISA). Of all tested patients, three (3/102, 2.94%, 95% CI: 0 ÷ 6.22) were confirmed for acute measles infection and two (2/102, 1.96%, 95% CI: 0 ÷ 4.65) for mumps. Double positive ELISA-IgM results were found in their serum samples and DBS. No acute rubella infection and rubella IgM marker were detected in both clinical samples. By immunoassay analysis of all 102 patients, measles, mumps and rubella IgG were found in 83/102 (81%, 95% CI: 73.40 ÷ 88.60), 76/102 (75%, 95% CI: 66.60 ÷ 83.40) and 79/102 (77%, 95% CI: 68.83 ÷ 85.17) serum samples.  Comparative results were obtained in the adequately obtained DBS. Viral IgG seroprevalence in DBS were obtained in 79/102 (77%, 95% CI: 68.83 ÷ 85.17) for measles, 69/102 (68%, 95% CI: 58.67 ÷ 77.33) for mumps and 73/102 (72%, 95% CI: 63 ÷ 81) for rubella, respectively. Double negative results for each screened viral markers were proven in six tested patients.The study shown higher extinction value (Ratio and NovaTec units) in DBS compared to serum samples of same persons were calculated. Our studies show over 90% coincidence in combined ELISA assay of viral markers against measles, mumps, and rubella in serum samples and DBS. DBS clinical approach is non-aggressive and more acceptable to the public (including young children, pregnant women, etc.). It has a variety of new and innovative applications in medicine and in particular in the laboratory diagnosis of acute and past (presence of protective immunity) measles, mumps and rubella infection in the phase of elimination

A Review on Dried Blood Spots (DBS) as Alternative, Archival Material for Detection of Viral Agents (Measles, Mumps, Rubella, Hepatitis B Virus)

In recent years there appears a variety of new and innovative applications of the dried blood spots. The areas of their range of application are medicine, neonatology, virology, microbiology, toxicology and pharmacokinetics, metabolic exchange, therapeutic drug monitoring, toxicology, and control of environmental pollution. The advantages of DBS technology can be combined into four main groups: (1) compared to conventional venipuncture, requires less blood volume, which is especially important in pediatrics and neonatology; (2) the procedure for blood collection is easy, inexpensive and noninvasive; (3) the risk of bacterial contamination or hemolysis is minimal; and (4) DBS can be maintained for a long time with almost no impact on the quality of the analysis. In recent years is increasing the application of DBS as method for seroepidemiological survey with focus viral infections: measles, mumps, rubella and hepatitis B virus. The DBS technique is optimized as an alternative approach (non-invasive, inexpensive, not requiring trained staff and cold chain for transport and storage) of venipuncture collection of clinical material in virology.This method facilitates the scientific researches about the concentration of virus specific antibodies in peripheral blood taken from a finger or heel; determining the percentage susceptibility / protection of the studied group of patients againt vaccine-preventable infectious - measles, mumps, rubella and hepatitis B; social benefits - non-invasive technique for testing of small children and infants and applications in regions in the countries with not well developed logistics infrastructure

Investigation of Biological and Prooxidant Activity of Zinc Oxide Nanoclusters and Nanoparticles

Zinc oxide (ZnO) nanomaterials offer some promising antibacterial effects. In this study, a new form of ZnO is synthesized, named ZnO nanocluster bars (NCs). Herein, ZnO NCs, ZnO nanoparticles (NPs), ZnO coated with silica (ZnO-SiOA, ZnO-SiOB), and SiO2 NPs were prepared, characterized, and their antimicrobial and prooxidant activity were tested. The prooxidant activity of all nanomaterials was studied according to free-radical oxidation reactions (pH 7.4 and pH 8.5) in chemiluminescent model systems. Each form of new synthesized ZnO nanomaterials exhibited a unique behavior that varied from mild to strong prooxidant properties in the Fenton`s system. ZnO NPs and ZnO NCs showed strong antibacterial effects, ZnO-SiOA NPs did not show any antibacterial activity representing biocompatibility. All tested NMs also underwent oxidation by H2O2. ZnO NCs and ZnO NPs exhibited strong oxidation at pH 8.5 in the O2-. generating system. While, SiO2, ZnO-SiOA andZnO-SiOB possessed pronounced 60-80% antioxidant effects, SiO2 NPs acted as a definitive prooxidant which was not observed in other tests. ZnO NCs are strong oxidized, assuming that ZnO NCs provide a slower release of ZnO, which leads to having a stronger effect on bacterial strains.  Thus, ZnO NCs are an important antibacterial agent that could be an emergent replacement of traditional antibiotics

The European venture capital landscape: an EIF perspective. Volume V: The economic impact of VC investments supported by the EIF

This paper examines the impact of venture capital (VC) investments supported by the EIF on the financial growth and performance of young and innovative firms. Using a novel dataset covering European start-ups supported by VC in the years 2007 to 2014, we generate a counterfactual group of non-VCbacked firms through a combination of exact and propensity score matching. To offset the relatively limited set of observables allowed by our data, we estimate treatment propensity using a series of innovative measures based on machine learning, network theory, and satellite imagery analysis. Our results document the positive effects of EIF-supported VC investments on start-up performance, as measured through various financial indicators (e.g. assets, revenue, employment). We find that VC financing enables start-ups to prioritise long-term growth, trading off short- to medium-term profitability if necessary. Overall, our work provides meaningful evidence towards the positive effects of EIF-supported VC investment on the financial growth of young and innovative businesses in Europe

Female access to finance: A survey of literature

This working paper examines the current academic literature on access to finance for female entrepreneurs and female-led enterprises. It covers two main financing markets: credit and venture capital (VC). The paper finds wide consensus in the academic field that gender-related credit and VC gaps exist in Europe. It also collects some of the most prominent empirical findings with respect to the gender imbalance in the European credit and VC markets during the last decade. This suggests an important role for gender-smart policy interventions at EU-level through the use of both equity and debt financing instruments

The European venture capital landscape: An EIF perspective. Volume VI: The impact of VC on the exit and innovation outcomes of EIF-backed start-ups

We use competing risks methods to investigate the causal link between venture capital (VC) investments supported by the EIF and the exit prospects and patenting activity of young and innovative firms. Using a novel dataset covering European start-ups receiving VC financing in the years 2007 to 2014, we generate a counterfactual group of non-VC-backed young and innovative firms via a combination of exact and propensity score matching. To offset the limited set of observables allowed by our data, we introduce novel measures based on machine learning, network theory, and satellite imagery analysis to estimate treatment propensity. Our estimates indicate that start-ups receiving EIF VC experienced a significant threefold increase in their likelihood to exit via M&A. We find a similarly large effect in the case of IPO, albeit only weakly significant. Moreover, we find that EIF VC contributed to a 13 percentage points higher incidence in patenting activity during the five years following the investment date. Overall, our work provides meaningful evidence towards the positive effects of EIF's VC activity on the exit prospects and innovative capacity of young and innovative businesses in Europe

Corrosion cast model and histological examination of the vascular system of the common stingray (Dasyatıs pastinaca) from the Black Sea

Published data in scientific literature on the anatomy and biology of common stingray (Dasyatis pastinaca) in the Black Sea are limited. The aim of the present study was to describe the most common variations in the main blood vessels that are important for respiration and reproduction of this species. For this purpose, 6 stingrays (3 males and 3 females) with an average body weight of 2533±174 g were obtained from a sea pound trap near the town of Varna, Bulgaria. After that, fish were sacrificed and the blood vessels were filled through the heart with self-curing castable resin Duracryl® Plus O. In addition, materials from blood vessels for histopathology examination were taken and fixed in 10% neutral formalin solution. Based on the corrosion cast and histological techniques, we described the structure and the interrelationships of the vascular pathways. It can be concluded that this study contributes to a description of the cardiovascular system of common stingray, which could be used to extend the existing information and contribute to the needs in the various field of biomedical engineerin

The market sentiment in European private equity and venture capital: Impact of COVID-19

This paper provides unique insights into the impact of the COVID-19 crisis on the European private equity (PE) and venture capital (VC) ecosystem. It achieves this purpose in two ways. By exploiting the recent survey wave of EIF's signature BA/VC/PE MM survey series, which was launched just prior to the COVID-19 outbreak in Europe, we are able to gauge how the pandemic changed the sentiment among European fund managers. This qualitative exercise is complemented by the results from a simple time series model that simulates the potential impact of the COVID-19 pandemic on the European PE and VC markets. Our analysis provides evidence that the European PE/VC ecosystem faces unprecedented challenges in the aftermath of the COVID-19 pandemic. A strong policy response in support of the PE/VC markets is imperative, to which EIF will be an indispensable contributor

Sol–Gel Synthesis of Silica–Poly (Vinylpyrrolidone) Hybrids with Prooxidant Activity and Antibacterial Properties

The present work deals with the sol–gel synthesis of silica–poly (vinylpyrrolidone) hybrid materials. The nanohybrids (Si-PVP) have been prepared using an acidic catalyst at ambient temperature. Tetramethyl ortosilane (TMOS) was used as a silica precursor. Poly (vinylpyrrolidone) (PVP) was introduced into the reaction mixture as a solution in ethanol with a concentration of 20%. The XRD established that the as-prepared material is amorphous. The IR and 29Si MAS NMR spectra proved the formation of a polymerized silica network as well as the hydrogen bonding interactions between the silica matrix and OH hydrogens of the silanol groups. The TEM showed spherical particle formation along with increased agglomeration tendency. The efficacy of SiO2/PVP nanoparticles as a potential antimicrobial agent against a wide range of bacteria was evaluated as bacteriostatic, using agar diffusion and spot tests. Combined effects of hybrid nanomaterial and antibiotics could significantly reduce the bactericidal concentrations of both the antibiotic and the particles, and they could also eliminate the antibiotic resistance of the pathogen. The registered prooxidant activity of the newly synthesized material was confirmative and explicatory for the antibacterial properties of the tested substance and its synergetic combination with antibiotics. The effect of new hybrid material on Crustacea Daphnia magna was also estimated as harmless under concentration of 0.1 mg/mL