SIM-OFE: Structure Information Mining and Object-aware Feature Enhancement for Fine-Grained Visual Categorization.

Fine-grained visual categorization (FGVC) aims to distinguish visual objects from multiple subcategories of the coarse-grained category. Subtle inter-class differences among various subcategories make the FGVC task more challenging. Existing methods primarily focus on learning salient visual patterns while ignoring how to capture the object's internal structure, causing difficulty in obtaining complete discriminative regions within the object to limit FGVC performance. To address the above issue, we propose a Structure Information Mining and Object-aware Feature Enhancement (SIM-OFE) method for fine-grained visual categorization, which explores the visual object's internal structure composition and appearance traits. Concretely, we first propose a simple yet effective hybrid perception attention module for locating visual objects based on global-scope and local-scope significance analyses. Then, a structure information mining module is proposed to model the distribution and context relation of critical regions within the object, highlighting the whole object and discriminative regions for distinguishing subtle differences. Finally, an object-aware feature enhancement module is proposed to combine global-scope and local-scope discriminative features in an attentive coupling way for powerful visual representations in fine-grained recognition. Extensive experiments on three FGVC benchmark datasets demonstrate that our proposed SIM-OFE method can achieve state-of-the-art performance.

Conformation-Confined Organic Butterfly-Molecule with High Photoluminescence Efficiency, Deep-Blue Amplified Spontaneous Emission, and Unique Piezochromic Luminescence.

Organic fluorophores with tunable π-conjugated paths have attracted considerable attention owing to their diverse properties and promising applications. Herein, we present a tailored butterfly like molecule, 2,2'-(2,5-bis (2,2-diphenylvinyl)-1,4-phenylene)dinaphtha-lene (BDVPN), which exhibits diverse photophysical features in its two polymorphs. The BP phase crystal, with its "aligned wings" conformation, possesses emissive characteristics that are nearly identical to those in dilute solutions. In contrast, the BN phase crystal, which adopts an "orthogonal wings" conformation, exhibits an unusual hypsochromic-shifted emission compared to its dilute solution counterparts. This intriguing hypsochromic-shifted emission originates from the reduction in the effective conjugated length of the molecular skeleton. Notably, BN phase crystals also exhibit exceptional optical performance, featuring high-efficiency emission (76.6%), low-loss optical waveguides (0.571 dB mm-1), deep-blue amplified spontaneous emission (ASE) with a narrow full width at half maximum (FWHM: 6.4 nm), and a unique 200 nm bathochromic shift of piezochromic luminescence.

Association between preoperative persistent hyperglycemia and postoperative delirium in geriatric hip fracture patients.

BACKGROUND: The management of preoperative blood glucose levels in reducing the incidence of postoperative delirium (POD) remains controversial. This study aims to investigate the impact of preoperative persistent hyperglycemia on POD in geriatric patients with hip fractures. METHODS: This retrospective cohort study analyzed medical records of patients who underwent hip fracture surgery at a tertiary medical institution between January 2013 and November 2023. Patients were categorized based on preoperative hyperglycemia (hyperglycemia defined as ≥ 6.1mmol/L), clinical classification of hyperglycemia, and percentile thresholds. Multivariate logistic regression and propensity score matching analysis (PSM) were employed to assess the association between different levels of preoperative glucose and POD. Subgroup analysis was conducted to explore potential interactions. RESULTS: A total of 1440 patients were included in this study, with an incidence rate of POD at 19.1% (275/1440). Utilizing multiple logistic analysis, we found that patients with hyperglycemia had a 1.65-fold increased risk of experiencing POD compared to those with normal preoperative glucose levels (95% CI: 1.17-2.32). Moreover, a significant upward trend was discerned in both the strength of association and the predicted probability of POD with higher preoperative glucose levels. PSM did not alter this trend, even after meticulous adjustments for potential confounding factors. Additionally, when treating preoperative glucose levels as a continuous variable, we observed a 6% increase in the risk of POD (95% CI: 1-12%) with each 1mmol/L elevation in preoperative glucose levels. CONCLUSIONS: There exists a clear linear dose-response relationship between preoperative blood glucose levels and the risk of POD. Higher preoperative hyperglycemia was associated with a greater risk of POD. CLINICAL TRIAL NUMBER: NCT06473324.

Terahertz flexible multiplexing chip enabled by synthetic topological phase transitions.

Flexible multiplexing chips that permit reconfigurable multidimensional channel utilization are indispensable for revolutionary 6G terahertz communications, but the insufficient manipulation capability of terahertz waves prevents their practical implementation. Herein, we propose the first experimental demonstration of a flexible multiplexing chip for terahertz communication by revealing the unique mechanism of topological phase (TP) transition and perseveration in a heterogeneously coupled bilayer valley Hall topological photonic system. The synthetic and individual TPs operated in the coupled and decoupled states enable controllable on-chip modular TP transitions and subchannel switching. Two time-frequency interleaved subchannels support 10- and 12-Gbit/s QAM-16 high-speed data streams along corresponding paths over carriers of 120 and 130 GHz with 2.5- and 3-GHz bandwidths, respectively. This work unlocks interlayer heterogeneous TPs for inspiring ingenious on-chip terahertz-wave regulation, allowing functionality-reconfigurable, compactly integrated and CMOS-compatible chips.

Tunable single emitter-cavity coupling strength through waveguide-assisted energy quantum transfer.

The emitter-cavity strong coupling manifests crucial significance for exploiting quantum technology, especially in the scale of individual emitters. However, due to the small light-matter interaction cross-section, the single emitter-cavity strong coupling has been limited by its harsh requirement on the quality factor of the cavity and the local density of optical states. Herein, we present a strategy termed waveguide-assisted energy quantum transfer (WEQT) to improve the single emitter-cavity coupling strength by extending the interaction cross-section. Multiple ancillary emitters are optically linked by a waveguide, providing an indirect coupling channel to transfer the energy quantum between target emitter and cavity. An enhancement factor of coupling strength g ̃ / g > 10 can be easily achieved, which dramatically release the rigorous design of cavity. As an extension of concept, we further show that the ancillae can be used as controlling bits for a photon gate, opening up new degrees of freedom in quantum manipulation.

Optofluidic crystallithography for directed growth of single-crystalline halide perovskites.

Crystallization is a fundamental phenomenon which describes how the atomic building blocks such as atoms and molecules are arranged into ordered or quasi-ordered structure and form solid-state materials. While numerous studies have focused on the nucleation behavior, the precise and spatiotemporal control of growth kinetics, which dictates the defect density, the micromorphology, as well as the properties of the grown materials, remains elusive so far. Herein, we propose an optical strategy, termed optofluidic crystallithography (OCL), to solve this fundamental problem. Taking halide perovskites as an example, we use a laser beam to manipulate the molecular motion in the native precursor environment and create inhomogeneous spatial distribution of the molecular species. Harnessing the coordinated effect of laser-controlled local supersaturation and interfacial energy, we precisely steer the ionic reaction at the growth interface and directly print arbitrary single crystals of halide perovskites of high surface quality, crystallinity, and uniformity at a high printing speed of 102 µm s-1. The OCL technique can be potentially extended to the fabrication of single-crystal structures beyond halide perovskites, once crystallization can be triggered under the laser-directed local supersaturation.

Solid-Liquid Phase Equilibria of a Quaternary Sulfate-Type System Containing Lithium, Rubidium, and Magnesium at 298.2 K.

The aim of this study was to obtain the relationship between ion interactions and the crystallization patterns of salt species in the lithium-rubidium-magnesium sulfate system at 298.2 K. The phase equilibria of the aqueous quaternary system Li+, Rb+, Mg2+//SO42--H2O were studied by the isothermal dissolution method at T = 298.2 K and p = 94.77 kPa. The density, refractive index, and composition of equilibrium solution were determined, on the basis of which solid-liquid phase diagrams and density/refractive index vs composition diagrams were drawn. The phase diagram consists of four quaternary invariant points and six crystallization regions, corresponding to the crystallization areas of single salts Rb2SO4, Li2SO4·H2O, and MgSO4·7H2O, as well as double salts 3Li2SO4·Rb2SO4·2H2O, Li2SO4·Rb2SO4, and Rb2SO4·MgSO4·6H2O. Notably, rubidium-containing double salts occupy more than 50% of the entire phase diagram area. The results indicate that the interactions between Li+ and Rb+ with coexisting Mg2+ and SO42- are complex, leading to the formation and precipitation of various lithium- and rubidium-bearing double salts, which hinder the effective concentrations of lithium and rubidium during the solar evaporation process in salt pans. Additionally, a multitemperature comparison of the solid-liquid phase diagrams at 273.2, 298.2, and 308.2 K reveals that temperature is also a significant factor influencing the solid-phase types and crystallization areas. For instance, the crystallization form of the double salt 3Li2SO4·Rb2SO4·2H2O changes to 3Li2SO4·Rb2SO4 at 308.2 K and the crystallization area of Li2SO4·Rb2SO4 gradually decreases, while the crystallization area of Rb2SO4·MgSO4·6H2O generally exhibits an increasing trend.

Combined effects of high-intensity ultrasound treatment and hydrogen peroxide addition on the thermal stabilities of myofibrillar protein emulsions at low ionic strengths.

In this study, the effects of high-intensity ultrasound (HIU) treatment combined with hydrogen peroxide (H2O2) addition on the thermal stability of myofibrillar protein (MP)-stabilized emulsions in low-salt conditions were investigated. Results showed that compared to using either HIU or H2O2 treatment alone, HIU treatment combined with H2O2 was most effective in enhancing the physical stability of emulsions. Moreover, the emulsion stabilized by MPs co-treated with HIU and H2O2 exhibited the most uniform distribution, highest absolute zeta potential, and optimal rheological properties upon heating. This combination effect during heating was caused by the inhibition of disulfide bond cross-linking of myosin heads by H2O2 and the dissociation of filamentous myosin structures using the HIU treatment. In addition, the results of oxidative stability analysis indicated that the addition of H2O2 increased the content of oxidation products; however, the overall influence on the oxidative stability of emulsions was not significant. In conclusion, the combination of HIU and H2O2 treatment is a promising approach to suppress heat-induced MP aggregation and improve the thermal stability of corresponding emulsions.

Risk factors for urinary tract infection in geriatric hip fracture patients: a systematic review and meta-analysis.

Background: Urinary tract infection (UTI) is a prevalent and consequential complication in hip fracture patients, leading to significant disability and heightened healthcare expenditures. Consequently, there is a critical need for a comprehensive systematic review to identify risk factors and establish early and effective preventive measures. Methods: A comprehensive search was performed across the PubMed, Cochrane, Embase, Web of Science, and Scopus databases (up to August 31, 2023). Article screening, data extraction, and quality assessment were independently completed by two reviewers. Results: Forty-four studies were eligible for inclusion, yielding an overall incidence rate of 11% (95% CI: 8%-14%). Our pooled analysis revealed 18 significant risk factors, including being female (OR = 2.23, 95% CI: 1.89-2.63), advanced age (MD = 1.35, 95% CI: 0.04-2.66), obesity (OR = 1.21, 95% CI: 1.11-1.31), catheterization (OR = 3.8, 95% CI: 2.29-6.32), blood transfusion (OR = 1.39, 95% CI: 1.21-1.58), American Society of Anesthesiologists ≥III (OR = 1.28, 95% CI: 1.18-1.40), general anesthesia (OR = 1.26, 95% CI: 1.11-1.43), intertrochanteric fracture (OR = 1.25, 95% CI: 1.01-1.54), hemiarthroplasty (OR = 1.43, 95% CI: 1.19-1.69), prolonged length of hospital stay (MD = 1.44, 95% CI: 0.66-2.23), delirium (OR = 2.66, 95% CI: 2.05-3.47), dementia (OR = 1.82, 95% CI: 1.62-2.06), Parkinson's disease (OR = 1.53, 95% CI: 1.46-1.61), diabetes (OR = 1.27, 95% CI: 1.13-1.43), hypertension (OR = 1.14, 95% CI: 1.03-1.26), congestive heart failure (OR = 1.35, 95% CI: 1.10-1.66), history of sepsis (OR = 7.13, 95% CI: 5.51-9.22), and chronic steroid use (OR = 1.29, 95% CI: 1.06-1.57). Conclusion: Our study identifies numerous risk factors strongly associated with UTI, offering compelling evidence and actionable strategies for improving clinical prediction, enabling early intervention, and facilitating targeted UTI management. Systematic review registration: identifier [CRD42023459600], https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=459600.

Chimera metasurface for multiterrain invisibility.

Invisibility, a fascinating ability of hiding objects within environments, has attracted broad interest for a long time. However, current invisibility technologies are still restricted to stationary environments and narrow band. Here, we experimentally demonstrate a Chimera metasurface for multiterrain invisibility by synthesizing the natural camouflage traits of various poikilotherms. The metasurface achieves chameleon-like broadband in situ tunable microwave reflection mimicry of realistic water surface, shoal, beach/desert, grassland, and frozen ground from 8 to 12 GHz freely via the circuit-topology-transited mode evolution, while remaining optically transparent as an invisible glass frog. Additionally, the mechanic-driven Chimera metasurface without active electrothermal effect, owning a bearded dragon-like thermal acclimation, can decrease the maximum thermal imaging difference to 3.1 °C in tested realistic terrains, which cannot be recognized by human eyes. Our work transitions camouflage technologies from the constrained scenario to ever-changing terrains and constitutes a big advance toward the new-generation reconfigurable electromagnetics with circuit-topology dynamics.

Laser manufacturing of spatial resolution approaching quantum limit.

Atomic and close-to-atom scale manufacturing is a promising avenue toward single-photon emitters, single-electron transistors, single-atom memory, and quantum-bit devices for future communication, computation, and sensing applications. Laser manufacturing is outstanding to this end for ease of beam manipulation, batch production, and no requirement for photomasks. It is, however, suffering from optical diffraction limits. Herein, we report a spatial resolution improved to the quantum limit by exploiting a threshold tracing and lock-in method, whereby the two-order gap between atomic point defect complexes and optical diffraction limit is surpassed, and a feature size of <5 nm is realized. The underlying physics is that the uncertainty of local atom thermal motion dominates electron excitation, rather than the power density slope of the incident laser. We show that the colour centre yield in hexagonal boron nitride is transformed from stochastic to deterministic, and the emission from individual sites becomes polychromatic to monochromatic. As a result, single colour centres in the regular array are deterministically created with a unity yield and high positional accuracy, serving as a step forward for integrated quantum technological applications.

Super-Resolution Exciton Imaging of Nanobubbles in 2D Semiconductors with Near-Field Nanophotoluminescence Microscopy.

Two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, have emerged as important candidate materials for next-generation chip-scale optoelectronic devices with the development of large-scale production techniques, such as chemical vapor deposition (CVD). However, 2D materials need to be transferred to other target substrates after growth, during which various micro- and nanoscale defects, such as nanobubbles, are inevitably generated. These nanodefects not only influence the uniformity of 2D semiconductors but also may significantly alter the local optoelectronic properties of the composed devices. Hence, super-resolution discrimination and characterization of nanodefects are highly demanded. Here, we report a near-field nanophotoluminescence (nano-PL) microscope that can quickly screen nanobubbles and investigate their impact on local excitonic properties of 2D semiconductors by directly visualize the PL emission distribution with a very high spatial resolution of ∼10 nm, far below the optical diffraction limit, and a high speed of 10 ms/point under ambient conditions. By using nano-PL microscopy to map the exciton and trion emission intensity distributions in transferred CVD-grown monolayer tungsten disulfide (1L-WS2) flakes, it is found that the PL intensity decreases by 13.4% as the height of the nanobubble increases by every nanometer, which is mainly caused by the suppression of trion emission due to the strong doping effect from the substrate. In addition to the nanobubbles, other types of nanodefects, such as cracks, stacks, and grain boundaries, can also be characterized. The nano-PL method is proven to be a powerful tool for the nondestructive quality inspection of nanodefects as well as the super-resolution exploration of local optoelectronic properties of 2D materials.

Nursing students' experiences of workplace violence based on the perspective of gender differences: a phenomenological study.

BACKGROUND: Workplace violence is a worldwide concern, and particularly affects nursing students. It has a seriously negative impact on nursing students' clinical learning experience and their physical and mental health. This study explored whether there are differences in psychological responses and coping styles among different gender nursing students after exposure to workplace violence, and investigated the causes for these differences. METHODS: We enrolled 22 nursing undergraduates from Guangzhou Medical University and Zunyi Medical University, China. Phenomenological qualitative research and online semi-structured interviews were conducted. The data were analyzed by the Colaizzi seven-step content analysis method. RESULTS: Two categories were collated: psychological experience and coping styles. Three themes of the former were extracted: negative emotional experience, low level of professional identity, and negative effect on self-efficacy. Two themes of the latter: responses to violence and adjustment after violence. In addition, fourteen subthemes were extracted. CONCLUSIONS: Different gender nursing students have different psychological experience and coping styles in the face of workplace violence. The causes of the differences are likely related to sociocultural factors and psychological gender status.

3D printing of inorganic nanomaterials by photochemically bonding colloidal nanocrystals.

3D printing of inorganic materials with nanoscale resolution offers a different materials processing pathway to explore devices with emergent functionalities. However, existing technologies typically involve photocurable resins that reduce material purity and degrade properties. We develop a general strategy for laser direct printing of inorganic nanomaterials, as exemplified by more than 10 semiconductors, metal oxides, metals, and their mixtures. Colloidal nanocrystals are used as building blocks and photochemically bonded through their native ligands. Without resins, this bonding process produces arbitrary three-dimensional (3D) structures with a large inorganic mass fraction (~90%) and high mechanical strength. The printed materials preserve the intrinsic properties of constituent nanocrystals and create structure-dictated functionalities, such as the broadband chiroptical responses with an anisotropic factor of ~0.24 for semiconducting cadmium chalcogenide nanohelical arrays.

High-sensitivity fiber optic temperature sensor based on CTFBG-FPI and Vernier effect.

A novel high-sensitivity temperature sensor based on a chirped thin-core fiber Bragg grating Fabry-Perot interferometer (CTFBG-FPI) and the Vernier effect is proposed and demonstrated. With femtosecond laser direct writing technology, two CTFBG-FPIs with different interferometric cavity lengths are inscribed inside a thin-core fiber to form a Vernier effect system. The two FPIs consist of two pairs of CTFBGs with a full width at half maximum (FWHM) of 66.5 nm staggered in parallel. The interferometric cavity lengths of the two FPIs were designed to be 2 mm and 1.98 mm as the reference arm and sensing arm of the sensor, respectively. The temperature sensitivity of this sensor was measured to be -1.084 nm/°C in a range of 40-90°C. This sensor is expected to play a crucial role in precision temperature measurement applications.

Coffee Silverskin Cellulose-Based Composite Film with Natural Pigments for Food Packaging: Physicochemical and Sensory Abilities.

To promote a circular economy, the use of agricultural by-products as food packaging material has steadily increased. However, designing food packaging films that meet consumers' preferences and requirements is still a challenge. In this work, cellulose extracted from coffee silverskin (a by-product of coffee roasting) and chitosan were combined with different natural pigments (curcumin, phycocyanin, and lycopene) to generate a variety of composite films with different colors for food packaging. The physicochemical and sensory properties of the films were evaluated. The cellulose/chitosan film showed favorable mechanical properties and water sensitivity. Addition of natural pigments resulted in different film colors, and significantly affected the optical properties and improved the UV-barrier, swelling degree, and water vapor permeability (WVP), but there were also slight decreases in the mechanical properties. The various colored films can influence the perceived features and evoke different emotions from consumers, resulting in films receiving different attraction and liking scores. This work provides a comprehensive evaluation strategy for coffee silverskin cellulose-based composite films with incorporated pigments, and a new perspective on the consideration of the hedonic ratings of consumers regarding bio-based films when designing food packaging.

Efficient second- and higher-order harmonic generation from LiNbO3 metasurfaces.

Lithium niobate (LiNbO3) is a material that has drawn great interest in nonlinear optics because of its large nonlinear susceptibility and wide transparency window. However, for complex nonlinear processes such as high-harmonic generation (HHG), which involves frequency conversion over a wide frequency range, it can be extremely challenging for a bulk LiNbO3 crystal to fulfill the phase-matching conditions. LiNbO3 metasurfaces with resonantly enhanced nonlinear light-matter interaction at the nanoscale may circumvent such an issue. Here, we experimentally demonstrate efficient second-harmonic generation (SHG) and HHG from a LiNbO3 metasurface enhanced by guided-mode resonance. We observe a high normalized SHG efficiency of 5.1 × 10-5 cm2 GW-1. Moreover, with the alleviated above-gap absorption of the material, we demonstrate HHG up to the 7th order with the shortest generated wavelength of 226 nm. This work may provide a pathway towards compact coherent white-light sources with frequency spanning into the deep ultraviolet region for applications in spectroscopy and imaging.

Polarization-Orthogonal Nondegenerate Plasmonic Higher-Order Topological States.

Photonic topological states, providing light-manipulation approaches in robust manners, have attracted intense attention. Connecting photonic topological states with far-field degrees of freedom (d.o.f.) has given rise to fruitful phenomena. Recently emerged higher-order topological insulators (HOTIs), hosting boundary states two or more dimensions lower than those of bulk, offer new paradigms to localize or transport light topologically in extended dimensionalities. However, photonic HOTIs have not been related to d.o.f. of radiation fields yet. Here, we report the observation of polarization-orthogonal second-order topological corner states at different frequencies on a designer-plasmonic kagome metasurface in the far field. Such phenomenon stands on two mechanisms, i.e., projecting the far-field polarizations to the intrinsic parity d.o.f. of lattice modes and the parity splitting of the plasmonic corner states in spectra. We theoretically and numerically show that the parity splitting originates from the underlying interorbital coupling. Both near-field and far-field experiments verify the polarization-orthogonal nondegenerate second-order topological corner states. These results promise applications in robust optical single photon emitters and multiplexed photonic devices.

High-Resolution Patterning of Perovskite Quantum Dots via Femtosecond Laser-Induced Forward Transfer.

High-resolution patterning of perovskite quantum dots (PQDs) is of significant importance for satisfying various practical applications, including high-resolution displays and image sensing. However, due to the limitation of the instability of PQDs, the existing patterning strategy always involves chemical reagent treatment or mask contact that is not suitable for PQDs. Therefore, it is still a challenge to fabricate high-resolution full-color PQD arrays. Here, we present a femtosecond laser-induced forward transfer (FsLIFT) technology, which enables the programmable fabrication of high-resolution full-color PQD arrays and arbitrary micropatterns. The FsLIFT process integrates transfer, deposition, patterning, and alignment in one step without involving a mask and chemical reagent treatment, guaranteeing the preservation of the photophysical properties of PQDs. A full-color PQD array with a high resolution of 2 µm has been successfully achieved. We anticipate that our facile and flexible FsLIFT technology can facilitate the development of diverse practical applications based on patterned PQDs.