Browse Articles

Enhanced early skin cancer detection through fusion of vision transformer and CNN features using hybrid attention of EViT-Dens169

Abstract Early diagnosis of skin cancer remains a pressing challenge in dermatological and oncological practice. AI-driven learning models have emerged as powerful tools for automating the classification of skin lesions by using dermoscopic images. This study introduces a novel hybrid deep learning model, Enhanced Vision Transformer (EViT) with Dens169, for the accurate classification of dermoscopic skin lesion images. The proposed architecture integrates EViT with DenseNet169 to leverage both global context and fine-grained local features. The EViT Encoder component includes six attention-based encoder blocks empowered by a multihead self-attention (MHSA) mechanism and Layer Normalization, enabling efficient global spatial understanding. To preserve the local spatial continuity lost during patch segmentation, we introduced a Spatial Detail Enhancement Block (SDEB) comprising three parallel convolutional layers, followed by a fusion layer. These layers reconstruct the edge, boundary, and texture details, which are critical for lesion detection. The DenseNet169 backbone, modified to suit dermoscopic data, extracts local features that complement global attention features. The outputs from EViT and DenseNet169 were flattened and fused via element-wise addition, followed by a Multilayer Perceptron (MLP) and a softmax layer for final classification across seven skin lesion categories. The results on the ISIC 2018 dataset demonstrate that the proposed hybrid model achieves superior performance, with an accuracy of 97.1%, a sensitivity of 90.8%, a specificity of 99.29%, and an AUC of 95.17%, outperforming existing state-of-the-art models. The hybrid EViT-Dens169 model provides a robust solution for early skin cancer detection by efficiently fusing the global and local features.

Community’s perceptions of the police during COVID-19 in Harlem, New York, a predominantly Black community: Social and geographical dimensions

Introduction Numerous demonstrations protesting policing practices towards the Black community have sprung up across the U.S. in recent years, especially during COVID-19. We examined the community’s perception of police and its association with social (e.g., a history of discrimination and community safety) and geographical (e.g., housing type and district community) factors in New York City. Methods An online survey of 393 adults in Harlem was conducted between April and September 2021. A 10-item questionnaire asked about police responsiveness, safety, and racism, with higher scores indicating more positive perception of the police. Multivariable linear regression examined the association of social and geographical factors with community perceptions of the police. Results The mean score of community’s perception of the police was 10.33 (SD = 3.73) out of 25, indicating a generally negative view. Notably, 39% doubted police’s capacity to handle mental health issues, 36% felt police were disrespectful to demonstrators, and 35% perceived police behavior as racist. In the adjusted model, younger age groups (18−29 years old: β = −2.45, 95%CI: −3.61, −1.28; 30−39 years old: β = −1.80, 95%CI: −2.82, −0.77 vs. 40−81 years old) showed significantly less favorable perceptions of the police. Higher education (associate’s or college degree: β = −0.83, 95%CI: −1.77, −0.10; bachelor’s or graduate degree: β = −2.10, 95%CI: −3.15, −1.05 vs. high school or less) and being employed (β = −2.15, 95%CI: −3.32, −0.99 vs. unemployed) were also associated with more negative perceptions. Those living in low-income housing (β = −0.87, 95%CI: −1.62, −0.12) rather than market-rate housing and facing discrimination (β = −1.94, 95%CI: −2.72, −1.16), had more negative perceptions of the police. Interestingly, community safety during COVID-19 (β = −0.63, 95%CI: −1.05, −0.20) was negatively associated with community’s perceptions of the police. No association was observed for gender and race/ethnicity. Conclusion A large proportion of Harlem residents have negative perceptions of the police, which are influenced by social and geographical factors. Implementing targeted community programs to build trust and partnerships with law enforcement may be particularly beneficial for economically disadvantaged communities exposed to violence.

Observation of excess polar magneto-optical Kerr effect signals in asymmetric Co/Tb-multilayers

We study the magneto-optical properties of asymmetric Co/Tb-multilayers that are designed to exhibit considerable Dzyaloshinskii–Moriya interaction (DMI) and low levels of effective perpendicular magnetic anisotropy. Accordingly, non-uniform magnetization states can occur in these films at intermediate magnetic field strengths, which cause a corresponding net magnetization reduction. Simultaneously, we observe an excess polar magneto-optical Kerr effect (MOKE) signal that increases beyond its value at saturation and is fully anticorrelated with the magnetization in its field dependency. We also find a very strong wavelength dependence of this excess polar MOKE signal that is very different from the MOKE behavior at saturation. All experimental data can be quantitatively explained by an additional polar MOKE mechanism that is associated with magnetic non-uniformities, such as, for instance, skyrmions, which have already been demonstrated to generate topological MOKE in certain compounds.

Machine learning models to identify significant factors of panic buying situation

Unpacking how teacher support enhances learning engagement in physical education: A serial mediation model of academic self-efficacy and task orientation among Chinese college students

Background Despite the Chinese government’s focus on student physical education, low student participation in physical activities persists, necessitating efforts to improve engagement. Purpose This study explores the relationship between teacher support and university students’ engagement in physical education, focusing on the mediating roles of academic self-efficacy and sport task orientation, Methods A quantitative analysis was conducted to investigate the mediation effects among 2,625 students from various regions and school types. Results The study demonstrated significant correlations between teacher support, academic self-efficacy, sport task orientation, and PELE. Teacher support was found to positively influence physical education learning engagement (PELE) both directly and through academic self-efficacy and sport task orientation. The model fit indices suggested a good fit, Conclusion The findings highlight the critical roles of teacher support, academic self-efficacy, and sport task orientation in enhancing students’ engagement in physical education, offering valuable insights for improving physical education practices.

Observation of anti-Stokes-fluorescence cooling in commercial Yb-doped silica fibers

Optical cooling of Yb-doped silica fibers using anti-Stokes fluorescence (ASF) has emerged as a powerful technique to produce fiber lasers and amplifiers that generate no heat. This paradigm offers an unprecedented opportunity to engineer a new generation of devices with greater power and frequency stability, smaller size, weight, and power consumption, and greater ease of power scaling. While cooling in silica has been demonstrated so far only in custom compositions, here we show that commercial Yb-doped silica fibers can also be cooled by ASF. The best of seven tested fibers cooled by −85 mK from ambient. This is, however, significantly less than the current record (−250 mK) held by a custom aluminophosphosilicate fiber with a similar core area. We show that the commercial fibers do not cool as well because of a lower Yb concentration, higher quenching, and/or higher background absorption. This work establishes that commercial fibers can be used to carry out valuable research on ASF cooling and athermal lasers. It also quantifies the significant improvements in Yb concentration, quenching suppression, and background-absorption reduction achieved in these custom silica compositions. These fibers are expected to have a major impact on fiber lasers and amplifiers, whose performance also depends critically on these three metrics.

Highly Flexible Porous Aromatic Frameworks with Exceptional Adsorption Capacity Toward Volatile Organic Compounds

AbstractIn this work we report a novel strategy to enhance the adsorption capacity of conventional porous materials by engineering intrinsic framework flexibility into porous aromatic frameworks (PAFs). Through Yamamoto‐type copolymerization of a rigid tetrahedral monomer (tetrakis(4‐bromophenyl)methane) and a flexible counterpart (tetrakis[(4‐bromophenoxy)methyl]methane), we synthesized a series of flexible PAFs (FPAF‐x, x = 0–2) with tunable flexibility. FPAF‐0.5 with moderate flexibility and surface area (854 m2 g−1) achieves exceptionally high volatile organic compound (VOC) adsorption capacities for various VOCs (e.g., 410.7 wt% for THF and 339.4 wt% for 3‐methylthiophene), outperforming many other porous materials reported to date. Both thermodynamic equilibrium and dynamics VOC vapor adsorption studies reveal that optimal flexibility enables guest‐adaptive structural transformation, allowing pore expansion to accommodate additional VOC molecules after initial pore filling. Moreover, polar and aromatic VOCs induce greater framework expansion than nonpolar analogues, which can also enhance the VOC uptake capacity in FPAFs. This work establishes flexibility engineering as a design principle for next‐generation adsorbents, improving the efficiency of VOC adsorption.

Performance of triangular fin device coated with (SiC–Co3O4)/diathermic nanolubricant inspired by convective and radiation conduction using AI driven approach

First-principles prediction of symmetry-enforced multifold fermionic and bosonic degeneracies in M3Sn (M <b>=</b> V, Nb) compounds

Topological quantum materials featuring multifold band crossings have opened unprecedented pathways in the exploration of exotic matter phases. These multifold crossings with three-, six-, and eightfold degeneracies hold exceptional significance, as they are ruled out in high-energy frameworks by Poincaré symmetry, making their realization in solids highly nontrivial. Notably, the coexistence of higher-fold fermionic (eightfold) and bosonic (sixfold) degeneracies in a single material is scarcely observed in literature. In this regard, we conducted a detailed investigation into the symmetry-protected topological characteristics of experimentally synthesized A15-type M3Sn (M = V, Nb) compounds using first-principles calculations. Our scrutiny unveils sixfold degeneracies in M3Sn compounds, which corresponds to the maximum allowed in bosonic systems along with threefold nodal points, while an eightfold and fourfold fermionic degeneracy are identified in V3Sn compound at the R-high-symmetry point protected by nonsymmorphic crystalline symmetry. The phonon and electronic surface states calculated from a tight-binding model further validate the multifold degeneracies and also represent complementary Dirac surface states at the Γ-point. The phononic Weyl nodal line along the Γ–R path exhibits nontrivial topology with ±π Berry phase. The synthesized compounds have been confirmed to theoretically exhibit both dynamic and thermal stabilities. Our findings offer a promising platform to explore exotic excitations within a single material, paving the way for deeper insights into complex quasiparticle behavior in these potential superconductors.

The relationship between the spatial and temporal patterns of urban noise dispersion and social perceptions

Hydrogen-assisted removal of oxygen vacancies in β-Ga2O3

Oxygen vacancies (VO) are intrinsic defects in β-Ga2O3 that significantly impact its device performance. These vacancies can donate electrons to the conduction band, leading to unintentional n-type conductivity in as-grown β-Ga2O3. In addition, VO associated localized states can act as electron traps, scatter free carriers, and consequently degrade carrier mobility and overall device performance. Therefore, removing VO is crucial for improving material properties, promoting the development of p-type β-Ga2O3 and optimizing device performance. Currently, traditional methods for VO treatment, such as oxygen plasma treatment and thermal annealing, are effective but have high energy consumption, which is detrimental to carbon neutrality goals. This study presents a method for enhancing the removal of VO via hydrogen doping. β-Ga2O3 thin films were grown under low-oxygen conditions using metal-organic chemical vapor deposition, followed by hydrogen pre-annealing. X-ray photoelectron spectroscopy and cathodoluminescence characterizations of films treated under different annealing conditions confirmed the effectiveness of hydrogen doping in promoting VO elimination. Furthermore, ultraviolet photodetectors were fabricated using these films, and the analysis of their dark-state decay times provided additional evidence for reduced VO concentrations. Theoretical calculations based on density functional theory using a revised PBE functional and the climbing image nudged elastic band method reveal that hydrogen incorporation induces charge redistribution, facilitating VO migration, thus enhancing defect control.

Assessment of extreme climate trends using temperature, rainfall, and cyclones in the West Bengal coastal region

Mid-infrared GaSb-based SAM APD with hole-initiated multiplication

The III–V-Sb separate absorption and multiplication (SAM) avalanche photodiode (APD) devices optimized for hole-initiated impact ionization have been developed. The hole-initiated process was selected to benefit from minimal valence band offset between InAsSb absorber and AlGaAsSb multiplier sections. The heterostructure design of the device facilitated shallow mesa fabrication, thereby minimizing etched sidewall leakage current. We tested devices with varying widths of the multiplier sections, with the most effective performance observed in SAM APDs featuring a 300 nm-thick multiplier section. The devices had cutoff wavelength of ∼3.9 μm at 80 K and operated in a background limited regime up to ∼200 K. The avalanche breakdown voltage was approximately −17.7 V at 80 K, increasing with temperature at a rate of 9.7 mV/K. An efficient hole-initiated impact ionization process resulted in multiplication gain values nearing one thousand, leading to peak values of current responsivity exceeding 50 A/W. It was observed that extensive tunneling occurs within the bias range between punch-through and avalanche breakdown, presumably due to the penetration of the electric field into the narrow bandgap absorber.

Translational Supramolecular Thioorthoester Chemistry

AbstractSupramolecular chemistry promises that insights into contact between molecules will open up new directions to approach significant questions in science and society. In this spirit, Kraus et al. report the translation of fundamentally new dynamic covalent thioorthoester chemistry into metal‐scavenging porous network materials and sulfur‐rich, leakage‐free cathode composites in lithium batteries (https://doi.org/10.1002/anov.70000).

The virtual prism represents the decentration component of the first-order term in a Fourier series of the corneal refractive power

Disentanglement of physical mechanisms for driving and detection in piezoelectric nanoelectromechanical systems

Nanoelectromechanical systems based on (Al,Ga)As/GaAs heterostructures with a two-dimensional electron gas can rely on both piezoelectric and electrostatic driving and detection. While this multifunctionality may be beneficial, disentanglement of these two physical mechanisms is important. In a multi-mode nanoelectromechanical system, we experimentally discern the electrostatic and piezoelectric effects in various configurations. A well-controlled system relying entirely on the electrostatic effect is demonstrated, where a field-effect transistor reads out the oscillations of its cantilevered side gate. We show that, apart from the two mentioned mechanisms, an additional time-delayed driving force arises due to the generation of bulk acoustic waves in the entire chip.

Insights from terrain influence on gamma dose rate variability in lower Shivalik Himalayas

Abstract This study focused on assessing how natural background radiation levels vary due to spontaneous gamma emissions from the terrain of the Haridwar district. Gamma radiation levels are influenced by a mix of environmental and structural factors. Outdoor radiation is closely connected to soil composition and geology, while indoor radiation is affected by both external conditions and the characteristics of building materials. The range of observed indoor dose rates has been found from 0.07 to 0.31 µSv/h with an average value of 0.15 µSv/h, and outdoor dose rates from 0.06 to 0.28 µSv/h with an average of 0.13 µSv/h. The terrain of the administrative map of Haridwar district has been classified into two categories based on altitude, viz., Highland and Lowland. The results show that unexpectedly high radiation in certain areas and subtle variations between highlands and lowlands suggest unmodeled factors may be contributing to radiation exposure patterns. Indoor spaces showed higher gamma radiation compared to outdoors. Radiation exposure changes depending on age, with infants receiving the most. The interplay of potential outliers has been discussed in detail.

A postbuckling-based metamaterial for switching the propagation of surface acoustic waves

The use of periodic materials for wave control and signal processing has been a focus of intensive research over the past two decades and continues to garner significant attention. Common signal processing mechanisms like switches and rectifiers often depend on magnetic fields and/or logic gates for their activation. We propose a metamaterial that enables the control of mechanical waves—surface acoustic waves—through an ON–OFF mechanism that switches the propagation of the waves through a tunable platform of elastic beams. In the OFF configuration, the beams remain in their undeformed state and resonate at a specific frequency range, creating a bandgap that stops wave propagation. Conversely, in the ON configuration, the beams undergo buckling, redistributing the vibration energy across multiple modes and eliminating the bandgap, thus allowing wave propagation. Analytical and numerical findings demonstrate the significant potential of this mechanism for controlling wave propagation in nonlinear periodic materials. This switching mechanism relies purely on mechanical processes, thereby eliminating the need for external fields.

Investigation of the effects of variable process conditions on the production of Apple snacks by explosion puffing drying

Multichannel visible light communication and sensing system over a single optical path

GaN multiple-quantum well (MQW) diodes inherently exhibit overlapping emission and detection spectra, enabling them to function as both a transmitter and a receiver simultaneously. This dual functionality allows for bidirectional data transmission over a single communication channel via time-division multiplexing. In this work, we propose and experimentally demonstrate a multichannel visible light communication and sensing system over a single optical path, integrating blue and green MQW transmitter/receiver pairs with a micro-magnetic field sensor. Two blue MQW diodes, coated with distributed Bragg reflectors that reflect blue light while transmitting green light, are positioned between two green MQW diodes, thereby enabling multiple communication channels over a single optical path. All nodes are symmetric and decentralized, forming a fully bidirectional optical communication network. When the external magnetic field strength changes the refractive index of the magnetic fluids, the received light is thus modulated for realizing external magnetic field sensing. This work paves a feasible way to develop complete mapping all-light communication and sensing integrated networks for diverse applications.