In a long-lasting major disease outbreak such as that of COVID-19, the challenge for public health authorities is to keep people motivated and keen on following safety guidelines. In this study, a ...compartmental model with a heterogeneous transmission rate (based on awareness) is utilized to hypothesize about the public adoption of preventive guidelines. Three subsequent outbreaks in South Korea, Pakistan, and Japan were analyzed as case studies. The transmission, behavior change, and behavioral change ease rates of the disease were measured in these countries. The parameters were estimated using the maximum likelihood method with an additional identifiability analysis performed to determine the uniqueness of the estimated parameters for quantitatively comparing them during the first three waves of COVID-19. The mathematical analysis and simulation results show that individual responses had a significant effect on the outbreak. Individuals declining to follow the public health guidelines in Korea and Japan between the second and third waves contributed to making the third peak the highest of the three peaks. In Pakistan, however, individual responses to following public health guidelines were maintained between the second and third waves, resulting in the third peak being lower than the first, rather than being associated with the highest transmission rate. Thus, maintaining a high level of awareness is critical for containing the spread. Improvised public health campaigns are recommended to sustain individual attention and maintain a high level of awareness.
Celotno besedilo
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In Bangladesh, community-based and peer-led prevention interventions for human immunodeficiency virus infection are provided to key populations (KPs) by drop-in centers (DICs), which are primarily ...supported by external donors. This intervention approach was adopted because public healthcare facilities were reportedly insensitive to the needs and culture of KPs, particularly with regard to the provision of sexually transmitted infection (STI) services. Nonetheless, in the absence of external funding, STI services need to be integrated into public healthcare systems.
A qualitative study was conducted in 2017 to understand the willingness of KPs to uptake the STI services of public healthcare facilities. Data were collected based on 34 in-depth interviews, 11 focus group discussions, and 9 key informant interviews. The social-ecological theoretical framework was used to analyze the data thematically and contextually.
Most participants were either resistant or reluctant to uptake STI services from public healthcare facilities because of their previous firsthand experiences (e.g., disrespectful and judgmental attitudes and behaviors), perceived discrimination, anticipatory fear, and a lack of privacy. Very few participants who had visited these facilities to receive STI services were motivated to revisit them. Nevertheless, they emphasized their comfort in DICs over public healthcare facilities. Thus, it appears that KPs can be situated along a care-seeking continuum (i.e., resistance to complete willingness). Unless policymakers understand the context and reasons that underlie their movement along this continuum, it would be difficult to encourage KPs to access STI services from public healthcare facilities.
KPs' willingness to uptake the STI services of public healthcare facilities depends not only on individual and community experiences but also on the nexus between socio-structural factors and health inequalities. Community mobilization and training about the needs and culture of KPs for healthcare professionals are essential. Therefore, addressal of a wide range of structural factors is required to motivate KPs into seeking STI services from public healthcare facilities.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Carbon Nanotubes (CNTs) are potential additives to polymeric materials as they can enhance the mechanical, structural, and electronic properties of the resulting polymeric composite. However, the ...improvement of different properties is not always guaranteed and the results usually depend on the specific polymer used, along with the quality and quantity of CNTs used in the polymer composite. In this work, a reactive force field (ReaxFF) is applied to perform molecular dynamics (MD) simulation to determine the change in mechanical properties of single-walled carbon nanotube (SWCNT)-reinforced Polyoxymethylene (POM) composite. We have varied the diameter of CNTs from 0.542 to 1.08 nm keeping the temperature constant at room temperature (300 K) and observed a significant change in the resulting mechanical property. Volume fraction of CNT and temperature are also varied and the results are presented through a stress-strain plot. After that, our Molecular Dynamics (MD) simulation result of CNT is compared with existing literature for code validation. Dependence of mechanical property on the interaction energy, fracture mechanism, and reasons behind it are discussed elaborately. It is clear from the results that the use of SWCNT in the polymer matrix of POM significantly improves the mechanical property of SWCNT-reinforced POM composite.
The HIV epidemic in Bangladesh is largely being driven by people who inject drugs (PWID) and mainly concentrated in Dhaka city. Intregrated biological and behavioural survey (IBBS) data of 2016 ...showed that a considerable percentage of the HIV positive PWID had unsafe sex with their female sex partners. Prevalence of HIV, risk behaviorus and vulnerabilities among the female sex partners of the PWID still remain unexplored.
To measure HIV prevalence, risk behaviours (drugs/injection/sexual) and vulnerabilities (treatment of and knowledge of sexually transmitted infections (STIs) and HIV/uptake of the routine HIV testing and HIV prevention services/physical and sexual violence), a quantitative survey was conducted among 227 female sex partners of the HIV positive PWID in Dhaka city in 2019 by adopting a take-all sampling technique.
The median age of participants was 34.0 years. Prevalence of HIV was 16.7% (95% CI: 12.4-22.2). Only 6.8% to 18.7% of the participants used condoms consistently with different male sex partners; only 6.8%cto 18.7% during last year. Seventy five percent (95% CI: 69.2-80.8) had no knowledge on STI symptoms. Self-reported symptoms of STIs were reported by 26% (95% CI: 20.7-32.1) and half sought treatment during last year. Nineteen percent (95% CI: 14.7-25.1) had comprehensive knowledge of HIV. As part of the routine HIV prevention services by the PWID drop-in-centres (DICs), 42.7% (95% CI: 36.4-49.3) of the participants were tested for HIV and knew their result within the last year. One-third never received HIV prevention services. During the last one year preceding the survey, 46% (95% CI: 39.3-52.6) reported been beaten and 20.2% (95% CI: 15.3-26.1) been raped.
It is urgently necessary to consider the high-risk behaviours and vulnerabilities in designing or to strengthen targeted interventions for female sex partners of the HIV positive PWID in Dhaka city to ensure equality in accessing and utilization of services.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A long-standing practice in the treatment of cancer is that of hitting hard with the maximum tolerated dose to eradicate tumors. This continuous therapy, however, selects for resistant cells, leading ...to the failure of the treatment. A different type of treatment strategy, adaptive therapy, has recently been shown to have a degree of success in both preclinical xenograft experiments and clinical trials. Adaptive therapy is used to maintain a tumor's volume by exploiting the competition between drug-sensitive and drug-resistant cells with minimum effective drug doses or timed drug holidays. To further understand the role of competition in the outcomes of adaptive therapy, we developed a 2D on-lattice agent-based model. Our simulations show that the superiority of the adaptive strategy over continuous therapy depends on the local competition shaped by the spatial distribution of resistant cells. Intratumor competition can also be affected by fibroblasts, which produce microenvironmental factors that promote cancer cell growth. To this end, we simulated the impact of different fibroblast distributions on treatment outcomes. As a proof of principle, we focused on five types of distribution of fibroblasts characterized by different locations, shapes, and orientations of the fibroblast region with respect to the resistant cells. Our simulation shows that the spatial architecture of fibroblasts modulates tumor progression in both continuous and adaptive therapy. Finally, as a proof of concept, we simulated the outcomes of adaptive therapy of a virtual patient with four metastatic sites composed of different spatial distributions of fibroblasts and drug-resistant cell populations. Our simulation highlights the importance of undetected metastatic lesions on adaptive therapy outcomes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
COVID-19 is caused by the SARS-CoV-2 virus, which is mainly transmitted directly between humans. However, it is observed that this disease can also be transmitted through an indirect route via ...environmental fomites. The development of appropriate and effective vaccines has allowed us to target and anticipate herd immunity. Understanding of the transmission dynamics and the persistence of the virus on environmental fomites and their resistive role on indirect transmission of the virus is an important scientific and public health challenge because it is essential to consider all possible transmission routes and route specific transmission strength to accurately quantify the herd immunity threshold. In this paper, we present a mathematical model that considers both direct and indirect transmission modes. Our analysis focuses on establishing the disease invasion threshold, investigating its sensitivity to both transmission routes and isolate route-specific transmission rate. Using the tau-leap algorithm, we perform a stochastic model simulation to address the invasion potential of both transmission routes. Our analysis shows that direct transmission has a higher invasion potential than that of the indirect transmission. As a proof of this concept, we fitted our model with early epidemic data from several countries to uniquely estimate the reproduction numbers associated with direct and indirect transmission upon confirming the identifiability of the parameters. As the indirect transmission possess lower invasion potential than direct transmission, proper estimation and necessary steps toward mitigating it would help reduce vaccination requirement.
A finite element procedure is proposed for wave propagation in elastic media. The method is based on an alternative formulation for the equations of motion that can systematically be constructed for ...linear evolutionary partial differential equations. A weak formulation—corresponding to convolutional variational principles—is then defined, which paves the way for introducing a particular type of time-wise shape functions. Next, some mathematical characteristics of the method are investigated, and upon those properties, a new solution procedure for elastodynamics problems is proposed. Subsequently, several numerical examples are considered, including a single degree of freedom mass-spring-damper system as the prototype of structural dynamics along with 1d and 2d elastodynamics problems for the case of the wave motion in elastic solids. The present method can be considered as an alternative approach for time integration and time-marching algorithms, e.g., Newmark’s algorithm, to solve time-domain problems in elastic media.
A maximum-tolerated dose (MTD) reduces the drug-sensitive cell population, though it may result in the competitive release of drug resistance. Alternative treatment strategies such as adaptive ...therapy (AT) or dose modulation aim to impose competitive stress on drug-resistant cell populations by maintaining a sufficient number of drug-sensitive cells. However, given the heterogeneous treatment response and tolerable tumor burden level of individual patients, determining an effective dose that can fine-tune competitive stress remains challenging. This study presents a mathematical model-driven approach that determines the plausible existence of an effective dose window (EDW) as a range of doses that conserve sufficient sensitive cells while maintaining the tumor volume below a threshold tolerable tumor volume (TTV). We use a mathematical model that explains intratumor cell competition. Analyzing the model, we derive an EDW determined by TTV and the competitive strength. By applying a fixed endpoint optimal control model, we determine the minimal dose to contain cancer at a TTV. As a proof of concept, we study the existence of EDW for a small cohort of melanoma patients by fitting the model to longitudinal tumor response data. We performed identifiability analysis, and for the patients with uniquely identifiable parameters, we deduced patient-specific EDW and minimal dose. The tumor volume for a patient could be theoretically contained at the TTV either using continuous dose or AT strategy with doses belonging to EDW. Further, we conclude that the lower bound of the EDW approximates the minimum effective dose (MED) for containing tumor volume at the TTV.
The COVID-19 pandemic has caused a global crisis with 47,209,305 confirmed cases and 1,209,505 confirmed deaths worldwide as of November 2, 2020. Forecasting confirmed cases and understanding the ...virus dynamics is necessary to provide valuable insights into the growth of the outbreak and facilitate policy-making regarding virus containment and utilization of medical resources. In this study, we applied a mathematical epidemic model (MEM), statistical model, and recurrent neural network (RNN) variants to forecast the cumulative confirmed cases. We proposed a reproducible framework for RNN variants that addressed the stochastic nature of RNN variants leveraging z-score outlier detection. We incorporated heterogeneity in susceptibility into the MEM considering lockdowns and the dynamic dependency of the transmission and identification rates which were estimated using Poisson likelihood fitting. While the experimental results demonstrated the superiority of RNN variants in forecasting accuracy, the MEM presented comprehensive insights into the virus spread and potential control strategies.
•Machine learning prediction helps public health resource management.•Mathematical modeling helps understand dynamic dependency of parameters on outbreak.•Analysis of mathematical epidemic model identify effective control strategies.
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