Search Results (1,211)

Organic optoelectronic devices receive appreciable attention due to their low cost, ecology, mechanical flexibility, band-gap engineering, brightness, and solution process ability over a broad area. In this study, we designed and studied organic light-emitting diodes (OLEDs) consisting of an assembly of natural dyes, extracted from noble fir leaves (evergreen) and blue hydrangea flowers mixed with poly-methyl methacrylate (PMMA) as light emitters. We experimentally demonstrate the effective conversion of blue light emitted by an inorganic laser/photodiode into longer-wavelength red and green tunable photoluminescence due to the excitation of natural dye–PMMA nanostructures. UV-visible absorption and photoluminescence spectroscopy, ellipsometry, and Fourier transform infrared methods, together with optical microscopy, were performed for confirming and characterizing the properties of light-emitting diodes based on natural dyes. We highlighted the optical and physical properties of two different natural dyes and demonstrated how such characteristics can be exploited to make efficient LED devices. A strong pure red emission with a narrow full-width at half maximum (FWHM) of 23 nm in the noble fir dye–PMMA layer and a green emission with a FWHM of 45 nm in blue hydrangea dye–PMMA layer were observed. It was revealed that adding monolayer MoS₂ to the nanostructures can significantly enhance the photoluminescence of the natural dye due to a strong correlation between the emission bands of the inorganic–organic emitters and back mirror reflection of the excitation blue light from the monolayer. Based on the investigation of two natural dyes, we demonstrated viable pathways for scalable manufacturing of efficient hybrid OLEDs consisting of assembly of natural-dye polymers through low-cost, purely ecological, and convenient processes. Full article

This review provides a comprehensive analysis of modern strategies for the synthesis, functionalization, and application of carbon nanotubes (CNTs) and graphene for the development of high-performance polymer composites in the field of strain sensing. The paper systematically organizes key synthesis methods for CNTs and graphene (chemical vapor deposition (CVD), such as arc discharge, laser ablation, microwave synthesis, and flame synthesis, as well as approaches to their chemical and physical modification aimed at enhancing dispersion within polymer matrices and strengthening interfacial adhesion. A detailed examination is presented on the structural features of the nanofillers, such as the CNT aspect ratio, graphene oxide modification, and the formation of hybrid 3D networks and processing techniques, which enable the targeted control of the nanocomposite’s electrical conductivity, mechanical strength, and flexibility. Central focus is placed on the fundamental mechanisms of the piezoresistive response, analyzing the role of percolation thresholds, quantum tunneling effects, and the reconfiguration of conductive networks under mechanical load. The review summarizes the latest advancements in flexible and stretchable sensors capable of detecting both micro- and macro-strains for structural health monitoring, highlighting the achieved improvements in sensitivity, operational range, and durability of the composites. Ultimately, this analysis clarifies the interrelationship between nanofiller structure (CNTs and graphene), processing conditions, and sensor functionality, highlighting key avenues for future innovation in smart materials and wearable devices. Full article

Outpatient neurosurgical oncology has expanded with advances in anesthesia, imaging, and minimally invasive techniques, enabling safe same-day discharge for selected patients undergoing procedures such as stereotactic biopsy and craniotomy. In this review, we find that across multiple international series, same-day discharge rates in several studies ranging from 85 to 95%, with low complication (3–6%) and readmission rates when structured pathways, including standardized selection criteria, enhanced recovery protocols, and routine 4-h postoperative CT imaging, are used. Studies on economic analyses demonstrate substantial cost savings driven by reduced inpatient bed utilization, with no increase in adverse events. Key challenges identified include medicolegal concerns amongst physicians, patient education, and limitations in organization adoption. Telemedicine and remote monitoring are increasingly incorporated to streamline preoperative evaluation and postoperative follow-up, improving access and continuity of care. Emerging technologies such as laser interstitial thermal therapy and focused ultrasound may further expand the outpatient neuro-oncology repertoire. Overall, current evidence supports outpatient neurosurgical oncology as a safe, efficient, and patient-centered model when applied with structured clinical pathways and patient selection. Full article

Background and Objectives: Secondary bacterial infection drives poor outcomes in older adults with COVID-19, but age-specific microbiology and its interaction with severity scores are not well defined. We characterized respiratory and pleural pathogens, resistance profiles, and their impact on day-5 SOFA/APACHE II in octogenarians versus younger adults. Methods: We performed a retrospective cohort study of adults with RT-PCR-confirmed coronavirus disease 2019 (COVID-19) at a tertiary infectious diseases center (≥80 years, n = 152; <65 years, n = 327). Respiratory and pleural samples were processed according to EUCAST standards. Identification employed matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Pathogen distributions, susceptibilities, and rates of superimposed pneumonia, empyema, and bacteremia were compared by age, and associations between secondary pneumonia, day-5 SOFA/APACHE II, and 28-day mortality were analyzed. Results: Sputum was obtained in 67.1% of older and 65.7% of younger adults, with numerically higher culture positivity in older patients (73.5% vs. 65.1%). Pathogen spectra were similar, dominated by Streptococcus pneumoniae (24.0% vs. 24.3%), methicillin-susceptible Staphylococcus aureus (MSSA) (18.7% vs. 20.7%), methicillin-resistant Staphylococcus aureus (MRSA) (9.3% vs. 6.4%), and Klebsiella pneumoniae, including extended-spectrum β-lactamase (ESBL)-producing strains. Empyema was more frequent in octogenarians (7.9% vs. 3.1%), and pleural cultures were usually positive. Meropenem retained 100% activity against ESBL-producing K. pneumoniae and Pseudomonas in both strata. In ≥80-year-olds, superimposed pneumonia was associated with higher day-5 SOFA (6.6 vs. 5.5) and APACHE II (24.3 vs. 21.0) scores and markedly increased 28-day mortality (37.5% vs. 9.8%). Conclusions: In octogenarians with COVID-19, secondary bacterial pneumonia and empyema are frequent, microbiologically similar to younger adults, and strongly amplify organ dysfunction and mortality even with largely preserved carbapenem susceptibility. Full article

Background: While intravenous administration of nanoparticles (NPs) is effective for targeting the lungs and liver, directing them to other organs and tissues remains challenging. Methods: Here, we report alternative administration routes that improve organ-specific accumulation of poly (lactic-co-glycolic acid) (PLGA) NPs (100 nm, negatively charged) loaded with the near-infrared dye Cyanine 7 (Cy7). NP cytotoxicity was evaluated in HEK293, mMSCs, C2C12, L929, and RAW264.7 cells. Hemocompatibility was assessed using WBCs and RBCs. NPs were administered via the tail vein, carotid, renal, and femoral arteries in BALB/c mice. Administration safety was evaluated by laser speckle contrast imaging and histological analysis. NP biodistribution and accumulation were assessed using in vivo and ex vivo fluorescence tomography and confocal microscopy of cryosections. Results: PLGA-Cy7 NPs demonstrate low cytotoxicity even at high doses and exhibit good hemocompatibility. Administration of NPs through the mouse carotid, renal, and femoral arteries significantly increases accumulation in the target ipsilateral brain hemisphere (31.7-fold) and salivary glands (28.3-fold), kidney (13.7-fold), and hind paw (3.6-fold), respectively, compared to intravenous administration. Injection of NPs through arteries supplying the target organs and tissues does not result in significant changes in blood flow, morphological alterations, or irreversible embolization of vessels, provided the procedure is performed correctly and the optimal dosage is used. Conclusions: These results highlight the potential of intra-arterial delivery of NPs for organ-specific drug targeting, underscoring the synergistic impact of advances in materials science, minimally invasive endovascular surgery, and nanomedicine. Full article

Background: Submacular hemorrhage (SMH) is a vision-threatening condition most associated with neovascular age-related macular degeneration (nAMD), although it may also arise from polypoidal choroidal vasculopathy, pathological myopia, retinal vascular diseases, trauma, and systemic factors. Rapid management is essential because subretinal blood induces photoreceptor toxicity, clot organization, and fibroglial scarring, leading to irreversible visual loss. The choice and urgency of treatment depend on hemorrhage size, duration, and underlying pathology, and the patient’s surgical risk category, which can influence the invasiveness of the selected procedure. This review aims to provide an updated synthesis of recent advances in the surgical and pharmacological management of SMH, focusing on evidence from the past five years and comparing outcomes across major interventional approaches. Methods: A narrative review of 27 recent clinical and multicentre studies was conducted. The included literature evaluated pneumatic displacement (PD), pars plana vitrectomy (PPV), subretinal or intravitreal recombinant tissue plasminogen activator (rtPA), anti-VEGF therapy, and hybrid techniques. Studies were analyzed about indications, surgical methods, timing of intervention, anatomical and functional outcomes, and complication and patient risk stratification. Results: Outcomes varied depending on the size and duration of hemorrhage, as well as the activity of underlying macular neovascularization. PD with intravitreal rtPA was reported as effective for small and recent SMH. PPV combined with subretinal rtPA, filtered air, and anti-VEGF therapy demonstrated favorable displacement and visual outcomes in medium to large hemorrhages or those associated with active nAMD. Hybrid techniques further improved clot mobilization in selected cases. Across studies, delayed intervention beyond 14 days correlated with reduced visual recovery due to blood organization and photoreceptor loss. Potential risks, including recurrent bleeding and rtPA-associated toxicity, were reported but varied across studies. Conclusions: Management should be individualized, considering hemorrhage characteristics and surgical risk. Laser therapy, including PDT, may serve as an adjunct in the perioperative or postoperative period, particularly in PCV patients. Early, tailored intervention typically yields the best functional outcomes. Full article

Diabetic cataract (DC) is a major complication of diabetes, with human lens epithelial cells (HLECs) playing a central role in its pathogenesis. Gigantol, a natural compound, has demonstrated protective effects against HLEC damage, yet its underlying mechanisms, particularly concerning cellular biophysical properties, remain poorly understood. This study investigated the protective role of gigantol against high-glucose-induced damage in HLECs, with a specific focus on alterations in cellular biophysical properties. Using a multi-technique approach including transmission electron microscopy (TEM), atomic force microscopy, laser scanning confocal microscopy, and Raman spectroscopy, we analyzed changes in ultrastructure, morphology, stiffness, roughness, membrane fluidity, and cytoskeletal organization. Treatment with gigantol effectively restored cellular ultrastructure, mitigated cytoskeletal disruption, and normalized key biomechanical properties: it reduced cell stiffness and roughness by approximately one-fourth, increased cell height by nearly onefold, and enhanced membrane fluidity by one-fifth. Raman spectroscopy indicated that gigantol improved membrane fluidity by modulating lipid bilayer structure, specifically through alterations in –CH₂– bending and –C=C– stretching modes. These findings demonstrate that gigantol protects HLECs from high-glucose-induced damage not only by biochemical means but also by restoring cellular biophysical homeostasis. This study provides novel biophysical–pathological insights into the anti-cataract mechanism of gigantol, highlighting its potential as a therapeutic agent that targets both biochemical and biophysical aspects of DC. Full article

Background/Objectives: Alveolitis, or “dry socket,” is a common complication after tooth extraction, associated with pain, inflammation and delayed healing. Standard surgical treatments are often invasive and insufficient. Laser therapy offers antimicrobial, anti-inflammatory and regenerative effects. This study aimed to compare the efficacy of 980 nm monolaser therapy and 980 nm and 1550 nm dual-wavelength therapy on alveolar socket healing in a rabbit model. Methods: In vitro tests evaluated bactericidal effects of 980 nm laser exposure. Eighteen adult male chinchilla rabbits underwent the extraction of the first incisors with the prevention of clot formation to model alveolar socket healing. On day 3, animals were randomized to three groups: mechanical curettage and antiseptic irrigation, 980 nm diode laser therapy, or combined 980 nm + 1550 nm therapy. Clinical parameters (hyperemia, edema, pain, socket closure) were assessed up to day 7. Histological and microbiological analyses were performed on days 7 and 12. Results: Laser therapy showed superior outcomes compared to mechanical treatment. In vitro, 980 nm exposure eradicated microorganisms after 3 s. By day 7, hyperemia decreased to 0.7 ± 0.6 points in the dual-laser group, versus 2.0 ± 0.0 (980 nm) and 3.0 ± 0.0 (mechanical). Complete socket closure occurred in 33% with mechanical treatment and in 67% of sites in the dual-laser group. Pain was fully resolved only after dual-laser therapy. Histology confirmed more organized granulation tissue and angiogenesis in the dual-laser group. Conclusions: Dual-wavelength laser therapy demonstrated superior anti-inflammatory, antimicrobial and regenerative effects compared with diode monotherapy and mechanical treatment. These findings highlight its promise as a minimally invasive approach for managing alveolitis, warranting further clinical evaluation. Full article

The present study investigates the synthesis and dispersibility process of iron oxide nanoparticles using laser pyrolysis with isopropanol vapors as a sensitizer agent. Similar to previous experiments (iron oxide nanoparticles synthesized by laser pyrolysis using ethylene as sensitizer gas), iron pentacarbonyl (Fe(CO)₅) was employed as an iron precursor; however, instead of the classic ethylene, isopropanol was chosen as a sensitizer, which indicated beneficial features (especially enhanced dispersibility in water) in the as-synthesized nanoparticles. Structural and elemental analysis confirmed the size range of the nanoparticles (nanometric), with crystallite sizes under 10 nm. Both raw nanoparticles, as well as the oleic acid stabilized ones, exhibited excellent colloidal stability in both water and organic fluids (Toluene, Chloroform, and DMSO): around 100 nm hydrodynamic diameter and more than 40 mV for zeta potential. The study highlights the advantages of using isopropanol as a sensitizer in the production of high-purity iron oxide nanoparticles from laser pyrolysis, particles that showcase superior dispersibility and functionalization potential. Full article

Chemical oxygen demand (COD) serves as a critical indicator for assessing the extent of water pollution caused by organic matter. This study proposes an integrated COD detection methodology that combines laser absorption spectroscopy with laser-induced fluorescence spectroscopy, enabling accurate measurement of COD parameters across a wide concentration range. For high-concentration COD, conventional ultraviolet absorption spectrophotometry based on the Lambert–Beer law is employed. However, since laser absorption spectrophotometry exhibits substantial errors in detecting low-concentration COD, laser-induced fluorescence spectroscopy is adopted for the precise quantification of trace-level COD. By integrating these two laser-based approaches, a spectroscopic COD detection system has been developed that simultaneously records absorbance after the laser passes through the sample and quantifies fluorescence intensity perpendicular to the beam with an image sensor, thereby achieving comprehensive COD analysis. Laboratory validation using COD standard solutions demonstrated relative errors below 11% across the concentration range of 2–220 mg/L. Further application to natural water samples confirmed that the integrated laser absorption–fluorescence spectroscopy approach achieves wide-range COD measurement with high sensitivity, a compact configuration, and rapid response, demonstrating strong potential for real-time online water quality monitoring. Full article

The stimulated assembly/disassembly of particles is a technique allowing for precise spatial and temporal control over the resulting structures to be realized. The application of a photosensitive liquid crystal (LC) allows the use of a photo-initiated order–disorder transition for the ordering and redistribution of dispersed nanoparticles. The semiconductor quantum dots (QDs) among them are useful for the imaging of such redistribution through simple luminescent microscopy with excitation by laser radiation at a wavelength of 532 nm. Doping the LC matrix with azo-chromophore molecules allowed us to localize the light-driven phase transition of the LC from the organized to the isotropic phase inside the spot, illuminated by ultraviolet (UV) light through a slit. The phase transition leads to a redistribution of the QDs within the matrix, followed by QD-rich region formation. After the termination of UV illumination, the QDs were found to form droplets in the region where UV illumination resulted in a homogeneous distribution of the QDs. The translation of the sample through the UV-illuminated spot resulted in QD accumulation inside the isotropic phase at the borders of the isotropic phase. The results obtained provide a good agreement with the model calculations of nanoparticle diffusion at the LC phase–isotropic liquid interface. Full article

Conventional seed viability assessment methods are often destructive, time-consuming, and highly sensitive to environmental conditions, resulting in estimated annual global agricultural losses exceeding 12 billion USD, as reported by the Food and Agriculture Organization (FAO) of the United Nations. To overcome these limitations, this study proposes a non-destructive framework for evaluating the viability of multiple pea seed varieties—including Gancui-2, Jinwan No.6, Hongyun 211, Mawan No.1, and Wuxuwan No.2—using laser speckle imaging (LSI). A He–Ne laser combined with a CCD camera was employed to capture 512-frame dynamic speckle sequences from 3000 seeds. A weighted generalized difference (WGD) algorithm was developed to enhance feature extraction by emphasizing physiologically relevant temporal variations through frame weighting based on the global mean and standard deviation of inter-frame differences. The extracted features were classified using an improved Weighted Generalized Residual Network (ResNet-W), which integrates weighted average pooling and 1 × 1 convolution to enhance feature aggregation and classification efficiency. Experimental results demonstrated strong performance, achieving 91.32% accuracy, 90.78% precision, 92.04% recall, and a 91.38% F1-score. The proposed framework offers a cost-effective, high-accuracy, and fully non-destructive solution for seed viability assessment, with significant potential for real-time agricultural quality monitoring and intelligent seed sorting applications. Full article

Insects rely on a variety of sensory cues for orientation, with antennae playing a central role in receiving and transmitting information about the environment. Philaenus spumarius (Hemiptera: Aphrophoridae), a spittlebug and vector of the bacterium Xylella fastidiosa, has a reduced number of antennal sensilla, yet demonstrates effective multimodal communication through olfactory and vibrational signals. This study aimed to investigate how the simplified sensory system of P. spumarius relates to the primary neuropils of the brain. We examined the ultrastructural organization of Johnston’s organ using scanning and transmission electron microscopy, complemented by previous data on antennal sensilla. Brain organization was investigated by Micro-CT and confocal laser scanning microscopy, which enabled us to identify the primary neuropiles. In addition, we conducted antennal and single sensillum backfills to trace sensory neurons to the brain. Our findings provide insight into the adaptation of a simplified sensory system for effective communication and orientation in P. spumarius. Full article

Rapid evaluation of water toxicity requires biological methods capable of detecting sub-lethal physiological changes without depending on chemical identification. Conventional microscopy-based bioassays are limited by low throughput and difficulties in observing small, transparent and fast-moving microorganisms. This study applies a laser-biospeckle, non-imaging microbioassay to assess the motility responses of Paramecium caudatum and Euglena gracilis exposed to two organic pollutants, trichloroacetic acid (TCAA) and acephate. Dynamic speckle patterns were recorded using a 638 nm laser diode (Thorlabs Inc., Tokyo, Japan) and a CCD camera (Gazo Co., Ltd., Tokyo, Japan) at 60 fps for 120 s. Correlation time, derived from temporal cross-correlation analysis, served as a quantitative indicator of motility. Exposure to TCAA (0.1–50 mg/L) produced strong concentration-dependent inhibition, with correlation time increasing up to 16-fold at 500× PL in P. caudatum (p < 0.01), whereas E. gracilis showed a delayed response, with significant inhibition only above 250× PL. In contrast, acephate exposure (0.036–3.6 mg/L) induced motility enhancement in both species, reflected by decreases in correlation time of up to 57% in P. caudatum and 40% in E. gracilis at 100× PL. Acute trends diminished after 24–48 h, indicating time-dependent physiological adaptation. These results demonstrate that biospeckled-derived correlation time sensitively captures both inhibitory and stimulatory behavioral responses, enabling real-time, high-throughput water toxicity screening without microscopic imaging. The method shows strong potential for integration into automated water-quality monitoring systems. Full article

By employing graded-interfaces modeling, ~10 μm-emitting quantum cascade lasers (QCLs) are designed with previously found conditions for record-high wall-plug efficiency (WPE) operation of mid-infrared QCLs: direct resonant-tunneling injection from a prior-stage low-energy state into the upper-laser level, photon-induced carrier transport, and carrier-leakage suppression via the step-taper active-region (STA) approach. For devices with interface-roughness (IFR) parameters characteristic of optimized molecular-beam-epitaxy (MBE) growth, a maximum front-facet pulsed WPE value of 19.6% is projected for 60-stages STA-type devices. This results from several factors: 19 mV voltage defect at threshold, 72% voltage efficiency at the maximum WPE point, and ~93% injection efficiency due to strong carrier-leakage suppression. 2.7 W peak front-facet power is projected. For devices with our metal–organic chemical vapor deposition (MOCVD)-growth IFR parameters, the projected maximum pulsed WPE value is 17.1%, i.e., 1.7 times higher than the highest reported front-facet WPE value from ~10 μm-emitting MOCVD-grown QCLs. Studies regarding the WPE value variation with the stage number, while employing waveguide designs having the same empty cavity loss, reveal that the maximum WPE value remains almost the same for 50–60 stages devices. In turn, there is potential for obtaining significantly higher CW powers than from conventional ~10 μm-emitting QCLs. Full article