Thermal rectification in novel two-dimensional hybrid graphene/BCN sheets: A molecular dynamics simulation.

The graphene-like monolayer of carbon, boron and nitrogen that maintains the native hexagonal atomic lattice (BCN), is a novel semiconductor with special thermal properties. Herein, with the aid of a non-equilibrium molecular dynamics approach (NEMD), we study phonon thermal rectification in a hybrid system of pure graphene and BCN (G-BCN) in various configurations under a series of positive and negative temperature gradients. We begin by investigating the relation of thermal rectification to sample's mean temperature, T, and the imposed temperature difference, ΔT, between the two heat baths at its ends. We then move to explore the effect of varying strain levels of our sample on thermal rectification, followed by Kapitza resistance calculations at the G-BCN interface, which shed light on the interface effects on thermal rectification. Our simulation results reveal a BCN-configuration-dependent behavior of thermal rectification. Finally, the underlying mechanism leading to a preferred direction for phonons is studied using phonon density of states (DOS) on both sides of the G-BCN interface.

Thermal conductivity and structural behavior of confined H2from molecular dynamics simulation.

In this work, we perform equilibrium molecular dynamics simulation to study the thermal conductivity of hydrogen molecules (H2) under extreme confinement within graphene nanochannel. We analyze the structural behavior of H2molecules inside the nanochannel and also examine the effect of nanochannel height, the number of H2molecules, and temperature of the system on the thermal conductivity. Our results reveal that H2molecules exhibit a strong propensity for absorption onto the nanochannel wall, consequently forming a dense packed layer in close to the wall. This phenomenon significantly impacts the thermal conductivity of the confined system. We made a significant discovery, revealing a strong correlation between the mass density near the nanochannel wall and the thermal conductivity. This finding highlights the crucial role played by the density near the wall in determining the thermal conductivity behavior. Surprisingly, the average thermal conductivity for nanochannels with a height (h) less than 27 Å exhibited an astonishing increase of over 12 times when compared to the bulk. Moreover, we observe that increasing the nanochannel height, while the number of H2molecules fixed, leads to a notable decrease in thermal conductivity. Furthermore, we investigate the influence of temperature on thermal conductivity. Our simulations demonstrate that higher temperature enhance the thermal conductivity due to increased phonon activity and energy states, facilitating more efficient heat transfer and higher thermal conductivity. To gain deeper insights into the factors affecting thermal conductivity, we explored the phonon density of states. Studying the behavior of hydrogen in confined environments can offer valuable insights into its transport properties and its potential for industrial applications.

Exploring a targeted approach for public health capacity restrictions during COVID-19 using a new computational model.

This work introduces the Queen's University Agent-Based Outbreak Outcome Model (QUABOOM). This tool is an agent-based Monte Carlo simulation for modelling epidemics and informing public health policy. We illustrate the use of the model by examining capacity restrictions during a lockdown. We find that public health measures should focus on the few locations where many people interact, such as grocery stores, rather than the many locations where few people interact, such as small businesses. We also discuss a case where the results of the simulation can be scaled to larger population sizes, thereby improving computational efficiency.

Molybdenum oxide nanotube caps decorated with ultrafine Ag nanoparticles: Synthesis and antimicrobial activity.

In the contemporary era, microorganisms, spanning bacteria and viruses, are increasingly acknowledged as emerging contaminants in the environment, presenting significant risks to public health. Nevertheless, conventional methods for disinfecting these microorganisms are often ineffective. Additionally, they come with disadvantages such as high energy usage, negative environmental consequences, increased expenses, and the generation of harmful byproducts. The development of next-generation antifungal and antibacterial agents is dependent on newly synthesized nanomaterials with inherent antimicrobial behavior. In this study, we report an arc-discharge method to synthesize MoOx nanosheets and microbelts, followed by decorating them with ultrafine Ag nanoparticles (NPs). Scanning and transmission electron microscopies show that Ag NPs formation on the Molybdenum oxide nanostructures rolls them into nanotube caps (NTCs), revealing inner and outer diameters of approximately 19.8 nm and 105.5 nm, respectively. Additionally, the Ag NPs are ultrafine, with sizes in the range of 5-8 nm. Results show that the prepared NTCs exhibit dose-dependent sensitivity to both planktonic and biofilm cells of Escherichia coli and Candida albicans. The anti-biofilm activity in terms of biofilm inhibition ranged from 19.7 to 77.2% and 11.3-82.3%, while removal of more than 70% and 90% of preformed biofilms was achieved for E. coli and C. albicans, respectively, showing good potential for antimicrobial coating. Initial MoOx exhibits positive potential, while Ag-decorated Molybdenum oxide NTCs show dual potential effects (positive for Molybdenum oxide NTCs and negative for Ag NPs. Molybdenum oxide NTCs, with their strong positive potential, efficiently attract microbes due to their negatively charged cell surfaces, facilitating the antimicrobial effect of Ag NPs, leading to cell damage and death. These findings suggest that the synthesized NPs could serve as a suitable coating for biomedical applications.

Health risk communication and infodemic management in Iran: development and validation of a conceptual framework.

OBJECTIVE: The COVID-19 pandemic exposed significant gaps in Iran's and other health systems' risk communication. The accompanying infodemic undermined policy responses, amplified distrust in government and reduced adherence to public health recommendations among the Iranian population. This study aimed to develop a conceptual framework for health risk communication and infodemic management (RCIM) during epidemics and health emergencies in Iran that could have potential applications in other contexts. DESIGN: This study was designed in two phases. Phase 1 involved semistructured qualitative interviews with key informants to explore effective RCIM strategies across public health settings in Iran and to develop a conceptual framework. Phase 2 involved revising the framework based on feedback from an online expert panel regarding its comprehensiveness and validity. SETTING: Provincial/national public health settings in Iran. PARTICIPANTS: Twenty key informants from provincial and national public health authorities who contributed to COVID-19 response programmes participated in interviews. Nine experts from diverse academic disciplines, provincial and national settings, and geographical locations participated in an online expert panel. RESULTS: The conceptual model was created based on qualitative interviews and expert panel discussions and was structured according to six pillars of the WHO health system framework: leadership and governance, information, health workforce and financial resources, along with media and community. Leadership and governance, including trustworthy leaders, were recommended as the foundation for developing RCIM in Iran. Developing an official strategy with information infrastructures, including high-quality surveillance systems, identified personnel and training for specialists among the health workforce, financial resources, communication channels and community engagement were recognised as other dimensions for developing health risk communication in Iran. CONCLUSION: The proposed framework represents a step toward establishing a national RCIM strategy in Iran. Further validation of the conceptual framework and experiments on how it could potentially influence policy and practice is recommended. This model has the potential to be applied in other contexts in its current form or as the foundation for customised local versions.

Performance of a convolutional autoencoder designed to remove electronic noise from p-type point contact germanium detector signals.

We present a convolutional autoencoder to denoise pulses from a p-type point contact high-purity germanium detector similar to those used in several rare event searches. While we focus on training procedures that rely on detailed detector physics simulations, we also present implementations requiring only noisy detector pulses to train the model. We validate our autoencoder on both simulated data and calibration data from an 241 Am source, the latter of which is used to show that the denoised pulses are statistically compatible with data pulses. We demonstrate that our denoising method is able to preserve the underlying shapes of the pulses well, offering improvement over traditional denoising methods. We also show that the shaping time used to calculate energy with a trapezoidal filter can be significantly reduced while maintaining a comparable energy resolution. Under certain circumstances, our denoising method can improve the overall energy resolution. The methods we developed to remove electronic noise are straightforward to extend to other detector technologies. Furthermore, the latent representation from the encoder is also of use in quantifying shape-based characteristics of the signals. Our work has great potential to be used in particle physics experiments and beyond.

Study of two-layer tapered depth of interaction PET detector.

Improving detection efficiency in small animal PET scanners without degrading spatial resolution is one of the main problems of these scanners. Commercial small animal PET scanners use different methods to achieve desirable levels of sensitivity and spatial resolution. GE Healthcare eXplore VISTA PET scanner uses double layer (LYSO-GSO) depth-of-interaction (DOI) capable cuboid detector modules. In this work, the design of GE Healthcare eXplore VISTA PET scanner is improved using tapered detector geometry instead of cuboid geometry. Using tapered detector geometry, the gaps between adjacent modules are filled and the sensitive volume has increased about 11.5%. The new designed PET scanner sensitivity and spatial resolution are studied for different crystal layer configurations (LYSO-GSO and GSO-LYSO with different thicknesses). As expected, average sensitivity over FOV is improved. Spatial resolution is slightly degraded but it is still uniform over FOV.

A long-lasting emerging epidemic of anthroponotic cutaneous leishmaniasis in southeastern Iran: population movement and peri-urban settlements as a major risk factor.

BACKGROUND: Epidemics of cutaneous leishmaniasis (CL) are occurring more frequently and spreading faster and farther than before in many areas of the world. The present study aimed to assess a long-lasting emerging epidemic (2005-2019) of 5532 cases with anthroponotic CL (ACL) in peri-urban areas of Kerman city in southeastern Iran. METHODS: This descriptive-analytical study was carried out for 15 years in Kerman province, southeastern Iran. The data were passively obtained through the health surveillance system and the Kerman Leishmaniasis Research Center. Every subject was diagnosed using direct smear microscopy. The representative causative agent was further examined by ITS1-PCR, PCR-RFLP, 7SL RNA gene sequencing and phylogenetic analyses. For each subject, a case report form designating demographic and clinical data was recorded. RESULTS: A different pattern of ACL incidence was found in peri-urban areas compared to that in the city of Kerman. The incidence rate of ACL cases has significantly increased (P < 0.001) from 2005 to 2016 in new settlements with a gradual decline after that. The overall average risk of contracting the disease was 7.6 times higher in peri-urban areas compared to Kerman city, an old endemic focus. All isolates consisting of six variants were confirmed to be Leishmania tropica. The overall pattern of the ACL infection indicates that the etiological agent of ACL is propagated and transmitted by the bite of female Phlebotomus sergenti sandflies from person to person from dissimilar clones as reflected by the complexity of the migrants' backgrounds in the province. CONCLUSIONS: The movement of populations and establishment of new settlements in peri-urban areas close to endemic areas are major risk factors for and are directly linked to CL. The underlying factors of this emerging ACL epidemic caused by L. tropica were disasters and droughts, among others. A robust commitment to a multilateral approach is crucial to make improvements in this area. This will require decisive coordinated actions through all governmental factions and non-governmental organizations. Furthermore, active and passive case detection strategies, early diagnosis, and effective treatment could help control the disease.

Stereochemistry and spectroscopic analysis of bis-Betti base derivatives of 2,3-dihydroxynaphthalene.

Density functional theory (DFT) was used to study the stereochemistry, thermodynamic stability, and spectra of recently synthesized bis-Betti base derivatives of 2,3-dihydroxynaphthalene obtained through multicomponent reactions of 2,3-dihydroxynaphthalene with aminoisoxazole and benzaldehyde derivatives. The stereochemistry of the products was investigated by theoretically calculating the infrared (IR) and proton nuclear magnetic resonance ((1)H NMR) spectra of the diastereomers and comparing them to the corresponding experimental data. The thermochemical properties of the reactions, including the enthalpy, internal energy, entropy, and Gibbs free energy, were also calculated. The diastereoselectivity of the reactions was estimated from the equilibrium distribution of diastereomers. According to the results, the synthesis of bis-Betti bases is exothermic and accompanied by a decrease in entropy. The energy difference between the diastereomers is quite small, but the Gibbs free energy change for the equilibrium syn <−> anti favors the anti over syn configuration. These results are in good agreement with experimental observations.

Synthesis of trans-1,3-diaryl-2-(5-methylisoxazol-3-yl)-2,3-dihydro-1H-naphtho[1,2-e][1,3]oxazines via bismuth(III)-catalyzed one-pot pseudo-four component reaction.

An expeditious, straightforward and efficient synthesis of diversely naphtho[1,2-e][1,3]oxazines via one-pot condensation reaction of ß- naphthol, 3-amino-5-methylisoxazole and arylaldehydes catalyzed by bismuth(III) trifluoromethanesulfonate is described. The reaction preferentially afforded 1,3-trans oxazines.