On-chip mid-infrared supercontinuum sources are fundamentally constrained by limited spectral bandwidth, insufficient dispersion control, and long interaction lengths that restrict scalable photonic integration. Current silicon nitride and hybrid waveguide platforms cannot simultaneously deliver octave-spanning mid-infrared coverage and millimeter-scale device footprints when pumped at telecommunication wavelengths. In this work, we overcome these limitations by introducing a dispersion-engineered hybrid dual-core waveguide that couples a high-index Si3N4 core with a lower-index Al2O3 core, enabling strong modal coupling and broadband supermode anti-crossing. The resulting dispersion profile provides wide anomalous group-velocity dispersion from the near-infrared to the mid-infrared, which is inaccessible in conventional single-core designs. Using a 50 fs pump pulse at 1550 nm with a peak power of 10 kW, the selected waveguide geometry produces a calculated supercontinuum spanning 0.81–6.71 μm, within a propagation length of only 2 mm, corresponding to more than three octaves of spectral broadening. Compared with state-of-the-art Si3N4-based and hybrid waveguides, this approach combines multi-octave numerical bandwidth with a 2 mm interaction length. These results establish the proposed Si3N4–Al2O3 dual-core platform as a CMOS-compatible solution for ultra-compact broadband mid-infrared light sources, enabling scalable on-chip spectroscopy, sensing, and integrated nonlinear photonic systems.
Homeless populations face multiple and intersecting vulnerabilities in rapidly urbanizing cities; however, the lived experiences of individuals residing beneath flyovers in Dhaka remain underexplored. This study explores their lived experiences, with particular attention to shelter, food security, safety, and personal identity, and challenges related to food, income, housing, safety risks, extreme weather, and sexual violence. By employing a qualitative design, data collection was conducted with 20 in-depth interviews (IDIs) using purposive sampling. The study used Interpretative Phenomenological Analysis (IPA) to facilitate an in-depth exploration of participants' lived experiences of homelessness. Themes were developed inductively from the raw data and subsequently interpreted within the study's theoretical framework. Data were analyzed using Braun and Clarke's six-stage thematic approach and NVivo 15 to facilitate systematic data coding. The findings reveal that people residing under flyovers face informal housing, food shortages, unstable informal incomes, exposure to harsh weather, dependence on begging, security risks, and experiences of sexual violence. Future large-scale mixed-methods research involving women, children, and people with disabilities is needed to provide a more comprehensive understanding of homelessness and vulnerability in urban Bangladesh. The findings provide evidence to inform more inclusive urban policies that integrate temporary shelter, accessible healthcare, livelihood support, and community safety for people experiencing homelessness beneath flyovers in Dhaka, Bangladesh.
On-chip mid-infrared supercontinuum sources are fundamentally constrained by limited spectral bandwidth, insufficient dispersion control, and long interaction lengths that restrict scalable photonic integration. Current silicon nitride and hybrid waveguide platforms cannot simultaneously deliver octave-spanning mid-infrared coverage and millimeter-scale device footprints when pumped at telecommunication wavelengths. In this work, we overcome these limitations by introducing a dispersion-engineered hybrid dual-core waveguide that couples a high-index Si 3 N 4 core with a lower-index Al 2 O 3 core, enabling strong modal coupling and broadband supermode anti-crossing. The resulting dispersion profile provides wide anomalous group-velocity dispersion from the near-infrared to the mid-infrared, which is inaccessible in conventional single-core designs. Using a 50 fs pump pulse at 1550 nm with a peak power of 10 kW, the selected waveguide geometry produces a calculated supercontinuum spanning 0.81–6.71 μ m, within a propagation length of only 2 mm, corresponding to more than three octaves of spectral broadening. Compared with state-of-the-art Si 3 N 4 -based and hybrid waveguides, this approach combines multi-octave numerical bandwidth with a 2 mm interaction length. These results establish the proposed Si 3 N 4 –Al 2 O 3 dual-core platform as a CMOS-compatible solution for ultra-compact broadband mid-infrared light sources, enabling scalable on-chip spectroscopy, sensing, and integrated nonlinear photonic systems.
Oral health is a critical yet often overlooked component of global health, with low- and middle-income countries and marginalized communities facing the greatest disparities in access and outcomes of oral health care. This narrative review synthesizes evidence from policy frameworks, program evaluations, and peer-reviewed literature from 2014 onward to explore effective strategies for bridging the global oral health gap. A narrative review was conducted for articles published between 2014 and 2025. Evidence was drawn from global initiatives, policy frameworks, and documented interventions addressing oral health, with a focus on sustainable and community-centered approaches. Global initiatives have advanced oral health policies, but top-down approaches alone are insufficient. Lasting improvement depends on community-centered, context-specific interventions, including evidence-based strategies like school programs, mid-level providers, and digital health tools. Integrating oral health into primary care and universal health coverage is essential, yet challenges such as funding gaps, service fragmentation, inequities, and weak political commitment remain. Public–private and intersectoral partnerships are key to overcoming these barriers and scaling effective solutions. This review emphasizes the need for robust monitoring systems, workforce development, and localized policy implementation guided by strong governance and advocacy. Future directions include leveraging artificial intelligence and tele-dentistry, addressing social determinants, and integrating oral health into broader health and development agendas. Achieving equitable global oral health requires a coordinated, evidence-driven, and community-engaged strategy supported by inclusive governance and sustained investment.
Alzheimer's disease (AD) is the most common cause of dementia and cognitive impairment; yet, there is currently no treatment. A buildup of Aβ, tau protein phosphorylation, oxidative stress, and inflammation in AD is pathogenic. The accumulation of amyloid-beta (Aβ) peptides in these neurocognitive areas is a significant characteristic of the disease. Therefore, inhibiting Aβ peptide aggregation has been proposed as the critical therapeutic approach for AD treatment. Resveratrol has been demonstrated in multiple studies to have a neuroprotective, anti-inflammatory, and antioxidant characteristic and the ability to minimize Aβ peptides aggregation and toxicity in the hippocampus of Alzheimer's patients, stimulating neurogenesis and inhibiting hippocampal degeneration. Furthermore, resveratrol's antioxidant effect promotes neuronal development by activating the silent information regulator-1 (SIRT1), which can protect against the detrimental effects of oxidative stress. Resveratrol-induced SIRT1 activation is becoming more crucial in developing novel therapeutic options for AD and other diseases that have neurodegenerative characteristics. This review highlighted a better knowledge of resveratrol's mechanism of action and its promising therapeutic efficacy in treating AD. We also highlighted the therapeutic potential of resveratrol as an AD therapeutic agent, which is effective against neurodegenerative disorders.
