Justification of binder material selection for carbon particles incorporation into fibrous electromagnetic radiation absorber

The paper presents justification of a binder material for incorporating carbon particles into the interfiber space of electromagnetic radiation absorber. A method for carbon particles incorporation into a fibrous material has been developed. It is based on applying a carbon-containing nanocomposite to the fibrous material’s surface. Previously, the research of carbon particles incorporation into a synthetic material by using an aqueous solution were carried out, which ensured a uniform distribution of carbon particles in the material structure. However, the properties of the material have changed significantly upon mechanical deformation. Therefore, the carbon particles incorporation process was investigated using various nanocomposites obtained on the basis of mixtures of vinyl acetate polymer, or epoxy polymer, or surface-active substance with carbon black. Based on the results of electron microscopic analysis and the reflection and transmission coefficients frequency dependences in the frequency range 0.7–17 GHz, the efficiency of using a nanocomposite based on a mixture of surface-active substance and carbon black to create electromagnetic radiation absorbers was justified. Such electromagnetic radiation absorbers have the transmission coefficient value about –18 dB and reflection coefficient value about –12 dB in the frequency range 7–13 GHz. Carbon-containing electromagnetic radiation absorbers based on fibrous material have thickness less than 3 mm, properties of flexibility and resistance to mechanical deformation. It can be used in various fields, in particular for hiding objects from radio frequency reconnaissance or protecting equipment from external interference.The paper presents justification of a binder material for incorporating carbon particles into the interfiber space of electromagnetic radiation absorber. A method for carbon particles incorporation into a fibrous material has been developed. It is based on applying a carbon-containing nanocomposite to the fibrous material’s surface. Previously, the research of carbon particles incorporation into a synthetic material by using an aqueous solution were carried out, which ensured a uniform distribution of carbon particles in the material structure. However, the properties of the material have changed significantly upon mechanical deformation. Therefore, the carbon particles incorporation process was investigated using various nanocomposites obtained on the basis of mixtures of vinyl acetate polymer, or epoxy polymer, or surface-active substance with carbon black. Based on the results of electron microscopic analysis and the reflection and transmission coefficients frequency dependences in the frequency range 0.7–17 GHz, the efficiency of using a nanocomposite based on a mixture of surface-active substance and carbon black to create electromagnetic radiation absorbers was justified. Such electromagnetic radiation absorbers have the transmission coefficient value about –18 dB and reflection coefficient value about –12 dB in the frequency range 7–13 GHz. Carbon-containing electromagnetic radiation absorbers based on fibrous material have thickness less than 3 mm, properties of flexibility and resistance to mechanical deformation. It can be used in various fields, in particular for hiding objects from radio frequency reconnaissance or protecting equipment from external interference

A situational picture of HIV/AIDS and injection drug use in Vinnitsya, Ukraine

BACKGROUND: New and explosive HIV epidemics are being witnessed in certain countries of Eastern Europe, including Ukraine, as well as a rapid and dramatic increase in the supply, use, and negative public health consequences of illicit drugs. A majority of registered HIV cases in Ukraine occur among injection drug users (IDUs), large numbers of whom report HIV risk behaviors such as needle sharing. The purpose of this study was to apply the World Health Organization's Rapid Assessment and Response on Injection Drug Use (IDU-RAR) guide to create a situational picture in the Vinnitsya Oblast, Ukraine, a region with very scarce information about the HIV/AIDS and injection drug use (IDU) epidemics. METHODS: The IDU-RAR uses a combination of qualitative data collection techniques commonly employed in social science and evaluation research to quickly depict the extent and nature of the given health problem and propose locally relevant recommendations for improvement. The investigators focused their assessment on the contextual factors, drug use, and intervention and policy components of the IDU-RAR. A combination of network and block sampling techniques was used. Data collection methods included direct observation, review of existing data, structured and unstructured interviews, and focus group discussions. Key informants and locations were visited until no new information was being generated. RESULTS: The number of registered HIV cases in Vinnitsya has increased from 3 (1987–1995) to 860 (1999–10/2004), 57 of whom have already died. Ten percent of annual admissions to the area's Regional Narcological Dispensary were for opiate disorders, and the number of registered IDUs rose by 20% from 1999 to 2000. The level of HIV/AIDS awareness is generally poor among the general population but high among high-risk populations. Both HIV/AIDS and injection drug use carry a strong stigma in the community, even among medical professionals. There was very little evidence of primary HIV/AIDS prevention efforts, and IDU prevention efforts focused on promotion of anti-drug messages in the schools. CONCLUSION: Given that Ukraine has sparse resources to be devoted to this problem, action recommendations should be prioritized, realistic, and initially targeted to persons in greatest need. The following action recommendations are prioritized by the following categories: First priority: Voluntary Counseling and Testing; Second Priority: Prevention and Education; and Third Priority: Harm Reduction and Treatment. They are provided in this sequence based on what response can realistically be implemented first with limited additional resources and can make the greatest immediate impact. The persons at greatest risk, HIV positive persons and IDUs, should be attended to first

Results of research on development of an intellectual information system of bankruptcy risk assessment of the enterprise

The article represents research results about the knowledge base development for the intellectual information system for the bankruptcy risk assessment of the enterprise. It is described the process analysis of the knowledge base development; the main process stages, some problems and their solutions are given. The article introduces the connectionist model for the bankruptcy risk assessment based on the analysis of industrial enterprise financial accounting. The basis for this connectionist model is a three-layer perceptron with the back propagation of error algorithm. The knowledge base for the intellectual information system consists of processed information and the processing operation method represented as the connectionist model. The article represents the structure of the intellectual information system, the knowledge base, and the information processing algorithm for neural network training. The paper shows mean values of 10 indexes for industrial enterprises; with the help of them it is possible to carry out a financial analysis of industrial enterprises and identify correctly the current situation for well-timed managerial decisions. Results are given about neural network testing on the data of both bankrupt and financially strong enterprises, which were not included into training and test sets

Results of research on development of an intellectual information system of bankruptcy risk assessment of the enterprise

The article represents research results about the knowledge base development for the intellectual information system for the bankruptcy risk assessment of the enterprise. It is described the process analysis of the knowledge base development; the main process stages, some problems and their solutions are given. The article introduces the connectionist model for the bankruptcy risk assessment based on the analysis of industrial enterprise financial accounting. The basis for this connectionist model is a three-layer perceptron with the back propagation of error algorithm. The knowledge base for the intellectual information system consists of processed information and the processing operation method represented as the connectionist model. The article represents the structure of the intellectual information system, the knowledge base, and the information processing algorithm for neural network training. The paper shows mean values of 10 indexes for industrial enterprises; with the help of them it is possible to carry out a financial analysis of industrial enterprises and identify correctly the current situation for well-timed managerial decisions. Results are given about neural network testing on the data of both bankrupt and financially strong enterprises, which were not included into training and test sets

The Commission on mental health in Ukraine: areas for development

peer reviewe

Patterns of daily oral HIV PrEP adherence among people who inject drugs in Ukraine: An analysis of biomarkers

Introduction: Daily oral HIV pre-exposure prophylaxis (PrEP) with tenofovir/emtricitabine (TDF/FTC) is recommended for people who inject drugs (PWID) but coverage is low. The real-life effectiveness of PrEP among PWID is unknown as previous studies were conducted in controlled settings and mainly relied on self-report. Analysis of PrEP metabolites-tenofovir diphosphate (TFVdp) and emtricitabine triphosphate (FTCtp)-offers an objective measure of adherence. Methods: To analyse longitudinal patterns of PrEP adherence among PWID in Ukraine, we used data from a community-based implementation trial conducted in Kyiv between July 2020 and March 2021 to test the efficacy of SMS reminders to improve adherence. Among 199 enrolled participants, 156 (78.4%) were retained through 6 months. Based on TFVdp/FTCtp levels assessed at 3 and 6 months, we identified groups with various adherence patterns (adherent at ≥2 doses/week, improved, worsened, non-adherent). Correlates of adherence were analysed using multinomial logistic regression. Results: Most participants (53.8%, n = 84/156) had no detectable metabolites at both assessments; 7.1% (n = 11/156) were consistently taking ≥2 doses/week; 1.3% (n = 2/156) were consistently taking ≥4 doses/week; 13.5% (n = 21/156) exhibited improved and 21.8% (n = 34/156) had worsened adherence at 6 compared to 3 months. "White coat compliance" (increased dosing prior to assessment) was common. Consistent adherence was associated with SMS reminders, younger age, employment, lower income, longer injection drug use duration, recent high-risk injecting (receptive syringe sharing, using pre-filled syringe, back- or front-loading, container sharing), absence of overdose in the past 6 months, perceived HIV risk through sexual intercourse and higher PrEP self-efficacy. Alcohol consumption was associated with inconsistent PrEP use. Groups with improved and worsened adherence did not differ. Conclusions: Daily oral PrEP may not achieve the desired effectiveness among PWID as a standalone intervention, calling for testing of alternative PrEP formulations and innovative integrated risk reduction strategies, especially in the context of HIV epidemics associated with injection drug use in eastern Europe and central Asia and the public health crisis in Ukraine caused by the war with Russia. SMS reminders may be effective among PWID who prioritize PrEP. Our findings offer practical guidance in identifying PWID who are likely to benefit from PrEP and those who need additional support.</p

Modes of HIV transmission among young women and their sexual partners in Ukraine

Background: Ukraine has the second-largest HIV epidemic in Europe, with most new cases officially attributed to heterosexual transmission. Indirect evidence suggested substantial HIV transmission from people who inject drugs (PWID) to their sexual partners. This study examined the extent of heterosexual HIV transmission between PWID and non-drug-using adolescent girls and young women (AGYW). Methods: A cross-sectional survey recruited AGYW diagnosed with heterosexually-acquired HIV between 2016 and 2019 in nine regions of Ukraine. AGYW were asked to identify and refer their sexual partners (‘Partners’), who subsequently underwent HIV testing, and, if positive, HCV testing. Both AGYW and Partners completed an interview assessing HIV risk behaviors prior to AGYW’s HIV diagnosis. Results: In August-December 2020, we enrolled 321 AGYW and 64 Partners. Among the Partners, 42% either self-reported IDU or were HCV-positive, indicating an IDU-related mode of HIV transmission. PWID Partners were more likely to report sexually transmitted infections (STI) and had lower educational levels. Of the 62 women who recruited at least one Partner, 40% had a PWID Partner. Within this subgroup, there was a higher prevalence of STIs (52% vs. 24%) and intimate partner violence (36% vs. 3%). Condom use was less common (52% vs. 38% reporting never use), and frequent alcohol or substance use before sex was higher (48% vs 30%) among AGYW with PWID Partner, although this difference did not reach statistical significance. Notably, 52% of women were aware of their Partners’ IDU. Conclusion: At least 40% of heterosexual transmission among AGYW in Ukraine can be linked to PWID partners. Intensified, targeted HIV prevention efforts are essential for key and bridge populations (PWID and their sexual partners), addressing the biological and structural determinants of transmission between key and bridge populations, such as IDU- and HIV status disclosure, STIs, IPV, and stigma.</p

HIV and hepatitis C virus infections among hanka injection drug users in central Ukraine: a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>Ukraine has experienced an increase in injection drug use since the 1990s. An increase in HIV and hepatitis C virus infections has followed, but not measures of prevalence and risk factors. The purposes of this study are to estimate the prevalence of HIV, HCV, and co-infection among injection drug users (IDUs) in central Ukraine and to describe risk factors for HIV and HCV.</p> <p>Methods</p> <p>A sample of 315 IDUs was recruited using snowball sampling for a structured risk interview and HIV/HCV testing (81.9% male, 42% single, average age 28.9 years [range = 18 to 55]).</p> <p>Results</p> <p>HIV and HCV antibodies were detected in 14.0% and 73.0%, respectively, and 12.1% were seropositive for both infections. The most commonly used drug was hanka, home-made from poppy straw and often mixed with other substances including dimedrol, diazepines, and hypnotics. The average period of injecting was 8.5 years; 62.5% reported past-year sharing needles or injection equipment, and 8.0% shared with a known HIV-positive person. More than half (51.1%) reported multiple sexual partners, 12.9% buying or selling sex, and 10.5% exchanging sex and drugs in the past year. Those who shared with HIV positive partners were 3.4 times more likely to be HIV positive than those who did not. Those who front- or back-loaded were 4 times more likely to be HCV positive than those who did not.</p> <p>Conclusion</p> <p>Harm reduction, addiction treatment and HIV prevention programs should address risk factors to stop further spread of both HIV and HCV among IDUs and to the general population in central Ukraine.</p