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1.
PLoS One ; 19(4): e0297476, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38635754

RESUMO

This paper mainly addressed the study of the transmission dynamics of infectious diseases and analysed the effect of two different types of viruses simultaneously that cause immunodeficiency in the host. The two infectious diseases that often spread in the populace are HIV and measles. The interaction between measles and HIV can cause severe illness and even fatal patient cases. The effects of the measles virus on the host with HIV infection are studied using a mathematical model and their dynamics. Analysing the dynamics of infectious diseases in communities requires the use of mathematical models. Decisions about public health policy are influenced by mathematical modeling, which sheds light on the efficacy of various control measures, immunization plans, and interventions. We build a mathematical model for disease spread through vertical and horizontal human population transmission, including six coupled nonlinear differential equations with logistic growth. The fundamental reproduction number is examined, which serves as a cutoff point for determining the degree to which a disease will persist or die. We look at the various disease equilibrium points and investigate the regional stability of the disease-free and endemic equilibrium points in the feasible region of the epidemic model. Concurrently, the global stability of the equilibrium points is investigated using the Lyapunov functional approach. Finally, the Runge-Kutta method is utilised for numerical simulation, and graphic illustrations are used to evaluate the impact of different factors on the spread of the illness. Critical factors that effect the dynamics of disease transmission and greatly affect the rate and range of the disease's spread in the population have been determined through a thorough analysis. These factors are crucial in determining the expansion of the disease.


Assuntos
Doenças Transmissíveis , Infecções por HIV , Sarampo , Humanos , Modelos Biológicos , Modelos Teóricos , Doenças Transmissíveis/epidemiologia , Sarampo/prevenção & controle
2.
Nanomaterials (Basel) ; 12(14)2022 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-35889729

RESUMO

In the present paper, the theoretical investigation of the device structure ITO/CeO2/SnS/Spiro-OMeTAD/Mo of SnS-based solar cell has been performed. The aim of this work is to examine how the Spiro-OMeTAD HTL affects the performance of SnS-based heterostructure solar cell. Using SCAPS-1D simulation software, various parameters of SnS-based solar cell such as work function, series and shunt resistance and working temperature have been investigated. With the help of Spiro-OMeTAD, the suggested cell's open-circuit voltage was increased to 344 mV. The use of Spiro-OMeTAD HTL in the SnS-based solar cell resulted in 14% efficiency increase, and the proposed heterojunction solar cell has 25.65% efficiency. The cell's performance is determined by the carrier density and width of the CeO2 ETL (electron transport layer), SnS absorber layer and Spiro-OMeTAD HTL (hole transport layer). These data reveal that the Spiro-OMeTAD solar cells could have been a good HTL (hole transport layer) in regards to producing SnS-based heterojunction solar cell with high efficiency and reduced cost.

3.
Nanomaterials (Basel) ; 12(13)2022 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-35808043

RESUMO

In the traditional surface plasmon resonance sensor, the sensitivity is calculated by the usage of angular interrogation. The proposed surface plasmon resonance (SPR) sensor uses a diamagnetic material (Al2O3), nickel (Ni), and two-dimensional (2D) BlueP/WS2 (blue phosphorous-tungsten di-sulfide). The Al2O3 sheet is sandwiched between silver (Ag) and nickel (Ni) films in the Kretschmann configuration. A mathematical simulation is performed to improve the sensitivity of an SPR sensor in the visible region at a frequency of 633 nm. The simulation results show that an upgraded sensitivity of 332°/RIU is achieved for the metallic arrangement consisting of 17 nm of Al2O3 and 4 nm of Ni in thickness for analyte refractive indices ranging from 1.330 to 1.335. The thickness variation of the layers plays a curial role in enhancing the performance of the SPR sensor. The thickness variation of the proposed configuration containing 20 nm of Al2O3 and 1 nm of Ni with a monolayer of 2D material BlueP/WS2 enhances the sensitivity to as high as 374°/RIU. Furthermore, it is found that the sensitivity can be altered and managed by means of altering the film portions of Ni and Al2O3.

4.
Sci Rep ; 12(1): 1894, 2022 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115646

RESUMO

Nanoelectromechanical systems (NEMS) have received great interest from researchers around the world since the advent of nanotechnology and nanoengineering. This can be attributed due to the unique characteristics of NEMS devices and their wide range of applications. Among these applications, nanobeams and nanotubes now have an important role in the design of a variety of NEMS engineering devices. In the current research, the thermoelastic vibration analysis of Euler-Bernoulli nanobeams has been investigated using the theory of non-local elasticity proposed by Eringen. Also to study the effect of temperature change, the generalized thermoelastic model with dual phase-lag (DPL) is applied. The studied nanobeam is subjected to an axial thermal excitation load and surrounded by a magnetic field of constant strength. The Laplace transform technique has been used to solve the system differential equations and to find an approximate analytical solution for the different physical fields of the nanobeam. The numerical results obtained for the studied variables have been graphically clarified and discussed analytically. The effects of various influencing factors such as magnetic field strength, temperature change, non-local parameter as well as ramp type parameter have been examined and studied in detail.

5.
Saudi Med J ; 40(10): 1032-1039, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31588483

RESUMO

OBJECTIVES: To assess the mass casualty incident (MCI) preparedness of pre-hospital care providers in Saudi Arabia and to identify and highlight their strengths and weaknesses when responding to MCIs.  Methods: This cross-sectional descriptive quantitative analysis was conducted between January 2017 and 2018 and included all Saudi Red Crescent Authority (SRCA) general administration branches in 13 regions in Saudi Arabia. The modified version of the emergency medical specialists (EMS) incident response and readiness assessment (EIRRA) tool was used in this study. Results: The Makkah region has the largest number of ambulances and medics vehicles, followed by Riyadh. Makkah and Al Madinah Al Munawarah obtained a median score of 4 and showed substantial preparedness for MCIs. However, Al Madinah Al Munawarah showed higher level of MCI preparedness than Makkah, and a significant difference was found (p=0.019). By contrast, Riyadh and the Eastern region showed limited MCI preparedness. In addition, a moderate positive correlation was observed between the overall median scores and the number of physicians (r=0.656 and p=0.015). Conclusion: The SRCA showed substantial preparedness in Makkah and Al Madinah Al Munawarah. The SRCA were highly prepared to face MCIs.


Assuntos
Planejamento em Desastres , Serviços Médicos de Emergência , Incidentes com Feridos em Massa , Ambulâncias/estatística & dados numéricos , Estudos Transversais , Planejamento em Desastres/organização & administração , Planejamento em Desastres/estatística & dados numéricos , Serviços Médicos de Emergência/organização & administração , Serviços Médicos de Emergência/estatística & dados numéricos , Humanos , Arábia Saudita
6.
Appl Opt ; 57(14): 3756-3760, 2018 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-29791338

RESUMO

We describe experiments where Fourier ptychographic microscopy (FPM) and dual-space microscopy (DSM) are implemented for imaging photonic crystals using a hemispherical digital condenser (HDC). Phase-recovery imaging simulations show that both techniques should be able to image photonic crystals with a period below the Rayleigh resolution limit. However, after processing the experimental images using both phase-recovery algorithms, we found that DSM can, but FPM cannot, image periodic structures with a period below the diffraction limit. We studied the origin of this apparent contradiction between simulations and experiments, and we concluded that the occurrence of unwanted reflections in the HDC is the source of the apparent failure of FPM. We thereafter solved the problem of reflections by using a single-directional illumination source and showed that FPM can image photonic crystals with a period below the Rayleigh resolution limit.

7.
Appl Opt ; 56(14): 4052-4057, 2017 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-29047535

RESUMO

Simulations were conducted to explore a broader collection of possible illumination patterns realizable using a white-light-emitting hemispherical digital condenser. Several simple, but practical, illumination patterns were selected and used in experiments where a sample was illuminated simultaneously from different directions. The illumination-direction multiplexing (IDM) Fourier ptychographic microscopy (FPM) method was successfully used for imaging and phase recovery. This study suggests that IDM-FPM can be used for imaging photonic crystals with subwavelength periods using traditional microscope condensers with variable numerical aperture.

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