Search Results (351)

Direct current (DC) surface flashover on polystyrene (PS) remains a critical bottleneck that impedes its reliable application in high-voltage insulation apparatus. To circumvent the protracted processing durations and stringent film-forming conditions inherent in conventional surface modification techniques, this study proposes a novel “liquid-film-assisted in situ rapid plasma curing” strategy. By harnessing atmospheric-pressure dielectric barrier discharge (DBD) technology within an argon ambient, the rapid (<6 min) and efficient deposition of a fluorosilane (FAS-13) functional coating onto the substrate was achieved. Microscopic characterizations coupled with isothermal surface potential decay (SPD) measurements reveal that this coating substantially mitigates the detrapping and surface migration of charge carriers. Macroscopic DC flashover testing corroborates that, under the optimal modification ratio, the surface breakdown voltage of PS is elevated to 14.04 kV, yielding an insulation gain of 26.94%. To elucidate the underlying physical mechanisms, density functional theory (DFT) calculations were conducted, revealing that the energy band misalignment between the wide-bandgap fluorinated layer and the substrate facilitates the construction of a high-density deep trap network (with a depth of ~0.8 eV) at the coating–substrate interface. By robustly anchoring primary electrons and inducing the formation of a homopolar space charge shielding layer, these deep traps physically arrest the evolution of the secondary electron emission avalanche (SEEA). Consequently, this work not only establishes a viable engineering framework for the rapid, large-scale surface reinforcement of DC insulation equipment but also provides profound quantum chemical insights into interfacial trap regulation within all-organic dielectrics. Full article

Laser-induced breakdown in water-rich biological media results from the interplay between primary photoionization processes and avalanche amplification of free electrons. Understanding this competition is essential for predicting ablation thresholds under ultrashort-pulse irradiation. In this work, we develop an analytical rate-equation model for the buildup of electron density in water-like biological tissues. It combines photoionization and chromophore ionization into a single seed-generation term, while avalanche ionization is described through a cascade gain factor. This formulation provides a framework for describing cascade electron-impact ionization processes in liquid-like media under strong-field excitation. Our approach gives an analytical expression for the temporal evolution of electron density driven by a Gaussian laser pulse and makes it possible to separate the contributions of direct ionization of water and ionization of chromophore centers. The analytical results are compared with numerical simulations that include carrier diffusion, bimolecular recombination and trapping. The comparison clarifies the roles of seed formation and cascade amplification in the growth of the electron population. The predicted dependence of threshold fluence on pulse duration agrees well with experimental data reported for water-like tissues such as the corneal tissues at a wavelength of 800 nm. The model provides a simple analytical picture of ultrafast plasma formation and electron-driven energy deposition in water-like biological media. Full article

Background/Objectives: Anabolic resistance is thought to underlie muscle loss in sarcopenia. Here, we investigated the adjuvant role of beta-hydroxy-beta-methylbutyrate (HMB), a leucine metabolite, on the acute muscle anabolic response to oral protein supplementation in older adults. Methods: A total of 24 community-dwelling older adults (68.5 ± 0.6 years; 13 men, 11 women) were randomized in a cross-over double-blind design to 40 g whey protein (Control) or 40 g whey protein with 3 g calcium–HMB (HMB). Subjects received a primed constant infusion of ¹³C₆ phenylalanine to assess muscle protein synthesis (MPS, by tracer incorporation in myofibrils) and muscle protein breakdown (MPB, via arterio-venous dilution) at baseline and post supplementation. Fasted and 3 h fed-state plasma HMB, aminoacidemia, rates of MPS, MPB, limb and muscle blood flow were measured. Results: In all subjects, both interventions displayed significant increases in MPS in response to feeding [fasted to 3 h-fed change (mean ± SEM, standard error of the mean). Males: control, +0.032 ± 0.006%.h⁻¹; HMB, +0.023 ± 0.004%.h⁻¹; females: control, +0.023 ± 0.006%.h⁻¹; HMB, +0.038 ± 0.006%.h⁻¹, p < 0.05]. In older women, the addition of HMB further enhanced the MPS response (fasted to 3 h-fed change, p = 0.0495) and area under the curve (p = 0.0364) versus protein alone. During the late-fed period, MPB significantly decreased in HMB versus control (p = 0.0298), and this was also observed when subjects were separated by sex (p = 0.0012). Conclusions: High-dose protein bolus feeding increased MPS in older adults. Surprisingly, 40 g whey did not maximize the anabolic response in older women, and HMB further increased the MPS feeding response to protein. HMB further suppressed the MPB feeding response over a longer period of time. Further work is needed to understand the apparent sexual dimorphic MPS response to high protein. Full article

This study demonstrates the application of Laser-Induced Breakdown Spectroscopy (LIBS) for the elemental analysis of agricultural soils in South Punjab, Pakistan. Soil degradation due to intensive farming, imbalanced fertilizer use, and declining organic matter has reduced crop productivity in the region. To address this, rapid and accurate soil diagnostics are essential. LIBS, coupled with Calibration-Free analysis (CF-LIBS), was employed to quantitatively determine the concentrations of major and trace elements—including calcium, silicon, iron, aluminum, magnesium, titanium, potassium, sodium, lithium, and barium—without requiring chemical standards. Plasma characterization was performed using the Boltzmann plot method, yielding temperatures between 7750 and 9000 K, and electron number densities were derived from Stark-broadened spectral profiles. The results reveal significant spatial variability in elemental composition, reflecting differences in land use and irrigation sources. This work confirms LIBS as a versatile, efficient, and reliable tool for soil health assessment, offering a practical solution for monitoring soil nutrients and supporting sustainable agricultural management in resource-limited settings. Full article

X-band copper resonating cavities are key components of future pulsed GHz normal-conductive multi-TeV accelerators. High electric field gradients are required for emerging applications; however, as gradients increase, components’ lifetime decreases, primarily due to radiofrequency (RF) breakdown. Coating technologies are being investigated in several laboratories to improve RF structure, performance and lifetime. To this end, we investigated the feasibility of fabricating nanometer-periodic Cu/Mo metallic multilayers on three-dimensional (3D) aluminum mandrels designed to replicate X-band copper resonating cavities. These nanometer-period multilayers are proposed to mitigate surface degradation due to electric breakdown at high accelerating gradients by stabilizing inner cavity surfaces against dislocation evolution and roughening caused by thermo-mechanical fatigue. High-Power Impulse Magnetron Sputtering (HiPIMS) in a bias-controlled dual closed-field magnetron configuration was employed to deposit alternating Mo and Cu nano-layers onto the 3D geometries. Given the complexity of HiPIMS technology, plasma pulse evolution was studied by combining time-resolved optical emission spectroscopy with electrical measurements of the pulse discharge. The influence of the process parameters, particularly the applied DC bias, on film growth was studied using non-destructive microprobe α-particle elastic backscattering spectrometry (µEBS) and scanning transmission electron microscopy (STEM). STEM and µEBS analyses confirmed that Mo layers with thicknesses of approximately 5–35 nm were successfully deposited repeatedly on thicker Cu layers (30–150 nm), preserving individual layer properties with minimal interdiffusion and alloying. The layers were deposited inside trenches with an aspect ratio of 5:1 representative of X-band irises. This technology, coupled with the replica process, could be applied to highly engineered nanostructured coatings for X-band cavity treatment in compact particle accelerator prototypes, as it may improve electrical breakdown lifetime under high accelerating fields, at least for degradation processes driven by the high mobility of copper dislocations. Full article

Electric energy metering cabinets serve as critical nodes in power grid operations, providing essential protection for key components in distribution networks. Under environmental stressors, the non-metallic casings of electric energy metering cabinets are susceptible to aging-induced performance degradation, which may result in electrical safety hazards. However, rapid and precise methods for evaluating the performance of these non-metallic casings are still lacking. Laser-Induced Breakdown Spectroscopy (LIBS), capable of rapid multi-element detection with non-contact analytical advantages, was employed in this study. Thermal aging experiments were conducted to investigate the performance degradation mechanisms of sheet molding compound (SMC)—a representative non-metallic cabinet material. The research analyzed time-dependent trends in material performance and microstructural evolution during aging. By integrating LIBS with multi-analytical techniques, this study further explored the feasibility of quantitatively evaluating the bending strength of thermally aged SMC, which has rarely been reported in previous studies. Based on LIBS spectral data, bending strength characterization revealed its attenuation patterns with aging duration. The relationships between bending strength and plasma temperature, as well as the characteristic line intensity ratios of K, Al, and Ca, were systematically examined. A multivariate linear regression model incorporating these key variables was subsequently developed, yielding a high coefficient of determination (R² = 0.9657) between the predicted and measured bending strength values. This model represents a promising initial step, but further validation with a larger dataset is necessary to enhance its reliability and generalizability. Full article

The non-thermal plasma (NTP) process is a promising advanced oxidation process (AOP) for removing non-biodegradable organics from wastewater, owing to the efficient formation of reactive chemicals. Despite its effective oxidizing capability, the decomposition mechanism of organic pollutants is not well understood. This study evaluates NTP for two representative sulfonamides (SMZ and STZ) and reports on (i) time-resolved removal to the method detection limit, (ii) transformation mapping using LC-ESI/MS/MS, which confirmed previously proposed hydroxylation and bond-cleavage pathways and further identified additional hydroxylated intermediates formed on the thiazole and benzene rings under NTP conditions, and (iii) energy evaluation through energy per order (EEO) within a single, reproducible operating window. The EEO values for SMZ and STZ degradation via NTP were calculated at 22.4 and 7.5 kWh/m³/order, respectively. These values are up to 37- and 118-fold lower than those reported for comparable AOPs, quantitatively confirming that the proposed NTP process achieves superior energy efficiency for sulfonamide degradation. Degradation is primarily attributed to reactive oxygen species (ROS) generated by plasma, which initiate the breakdown of the antibiotic structure. Overall, this study demonstrates that NTP is a highly effective AOP for driving the rapid primary degradation and intermediate structural transformation of recalcitrant sulfonamide antibiotics. Full article

At the end of its last experimental campaign, in December 2023, the Joint European Torus (JET) became available for testing a compact and lightweight Laser-Induced Breakdown Spectroscopy (LIBS) system to be mounted on its robotic arm. The purpose of the test was the in situ chemical characterization of its internal walls and plasma-facing components (PFCs). Among the areas measured, special attention was devoted to the PFCs of the divertor, as this area is most affected by the re-deposition of material eroded from the first wall and unburned nuclear fuel (deuterium and tritium). In this article, we present the results of the LIBS characterization of a PFC of the High Field Gap Closure (HFGC), highly subjected to these phenomena. The in-depth distribution of several ITER-relevant chemical species is discussed through in-depth and correlation analyses, and the interpretation of the results is explained in terms of erosion and re-deposition of materials from the first wall. The study allowed us to estimate the thickness of the ablated layers by each laser shot, which is on the order of a few tens of nanometers, and to outline a mapping of the thickness of the re-deposited material. Full article

Thoracoabdominal aortic aneurysms (TAAAs) are uncommon and usually silent until rupture, causing a substantial burden to the health care system. Aneurysm growth and rupture prediction is mainly based on aneurysm diameter measurement by imaging modalities, meaning that the biology of aneurysm growth is not part of a potentially more adequate surveillance of aortic aneurysm patients. Alternatives or complementary options for aortic aneurysm surveillance are an ongoing, non-addressed open issue of vascular medicine. The application of different biomarkers has been discussed, yet so far, an adequate candidate for aortic aneurysm surveillance, if it comes to the thoracic or thoracoabdominal aorta, preferably without radiation exposure, has not been named. Elastin breakdown, as a component of aortic wall degeneration primarily driven by matrix metalloproteinases (MMPs), is a core element of aneurysm development. Desmosine is an elastin-specific cross-link increasingly studied as a circulating or urinary biomarker of compromised aortic wall integrity and disease activity. Accordingly, this review investigated whether plasma desmosine (pDES), a highly specific marker of elastin degradation, could be used as a non-invasive biomarker for detecting aortic aneurysms and assessing their risk profile. The existing literature of desmosine in fields of aortic pathologies in the acute and chronic setting will be assessed based on the current literature; furthermore, future perspectives of desmosine as a biomarker of aortic pathologies, such as aortic aneurysm dynamics, will be discussed. Full article

Osteoarthritis (OA) represents a degenerative joint disease which advances through cartilage breakdown, synovial inflammation, and subchondral bone transformation until it causes persistent pain and mobility loss. The scientific community lacks complete knowledge about OA disease mechanisms and post-operative healing processes despite arthroplasty surgery providing effective symptom relief. This study investigated plasma proteomic changes in OA patients before and after arthroplasty. The cohort included eight OA patients undergoing knee or hip arthroplasty and ten age-, sex-, and body mass index-matched healthy controls. Plasma proteins were analyzed using liquid chromatography–tandem mass spectrometry following enzymatic digestion and depletion of high-abundance components. The bioinformatic analysis together with quantitative methods showed that OA patients experienced changes in inflammatory pathways, extracellular matrix remodeling, immune system regulation and coagulation processes. A total of 93 proteins were differentially abundant in the pre-operative comparison. Among these, 63 proteins were consistently up-regulated and 23 were consistently down-regulated across both pre- and post-operative time points. In addition, 20 proteins exhibited post-operative-specific changes. These findings highlight both persistent disease-associated alterations and transient proteomic shifts linked to post-operative recovery. Overall, this study identifies candidate plasma proteomic signatures associated with OA and surgical intervention, providing exploratory insights into disease monitoring and potential personalized therapeutic strategies. Full article

Background: Deep vein thrombosis (DVT) is one of the most common cardiovascular diseases and is especially prevalent in areas with environmental pollution. Bioaccumulation of toxic heavy metals may lead to deterioration of homeostasis with cellular change, endothelial dysfunction, DNA impairment and cellular signaling. The reason for this is usually the accumulation of thrombogenic toxins in the body as a result of long-term exposure or a lack of regulatory gene expression. In this study, we aimed to measure the minerals that potentially accumulate in the nail. The measurement method was laser-induced breakdown spectroscopy (LIBS), which is a form of atomic emission spectroscopy. It uses a highly energetic laser source to form a plasma of excited atoms emitting light of characteristic wavelengths. It provides accurate quantification and reveals the relationship between tissue accumulation of toxic heavy metals and DVT formation. Methods: Between January 2020 and December 2021, 100 patients diagnosed with lower-extremity deep vein thrombosis were screened in a single tertiary healthcare center. Among them, 50 patients who met the eligibility criteria and consented to participate were included in the study. An additional 50 age-matched healthy volunteers were enrolled as controls. Demographic and clinical characteristics were recorded. Nail samples were obtained from each participant, and elemental emission intensities were quantitatively analyzed using laser-induced breakdown spectroscopy (LIBS). Results: No difference in clinical characteristics was detected between the groups. While iron, calcium and silicon were found to be high in DVT patients, magnesium was found to be low. Regarding the magnesium emission, ROC analysis showed 76–90% specificity and 69–82% sensitivity, respectively. Conclusions: LIBS is a useful method because it is easy to use and can be used with a small sample. According to the results of our study, information about the pathogenesis of DVT was obtained through nail analysis. Therefore, we believe that LIBS analysis is a method that may be useful in determining the causes and predisposing factors for DVT. Full article

Objective: Resistance exercise can induce muscle damage that impairs sports performance and cellular repair. Myokines, particularly mitochondrial myokines, play an important role in regulating energy metabolism and muscle recovery. The ACTN3 R577X polymorphism, which alters the expression of α-actinin-3 in muscle fibers, may influence myokine responses by modulating exercise adaptation and recovery. Methods: Seventy-five amateur runners (30–55 years) from the São Paulo International Marathon were evaluated. Plasma levels of mitochondrial myokines (BDNF, FGF-21, FSTL, IL-6, apelin, IL-15, musclin, and myostatin) were measured before and after the race and correlated with ACTN3 R577X genotypes. Results: In this study, the genotypic frequencies of the ACTN3 R577X polymorphism were 36% (RR), 39% (RX), and 14% (XX). Plasma concentrations of BDNF, FSTL, FGF-21, and IL-6 increased immediately after running across all genotypes, with no significant differences observed between genotypes. In contrast, plasma levels of myostatin, musclin, IL-15, and apelin decreased during the recovery period only among runners carrying the R allele. Conclusions: Mitochondrial myokine responses to resistance exercise were not substantially different among genotypes of the ACTN3 R577X polymorphism. However, myokines associated with protein breakdown and bioenergetic adaptation were reduced during the recovery period in runners carrying the R allele, which may impact muscle repair and bioenergetic adaptation. Full article

Thoracoabdominal aortic aneurysms (TAAAs) are rare and often remain asymptomatic until rupture, leading to high morbidity and mortality. Elastin degradation, largely mediated by matrix metalloproteinases (MMPs), plays a central role in their pathogenesis. This study aimed to evaluate plasma desmosine (pDES), a specific biomarker of elastin breakdown, as a non-invasive tool for TAAA detection and risk stratification. In a prospective single-centre case–control study, 30 patients with TAAA and 30 age- and sex-matched controls were enrolled. Plasma pDES levels were quantified using liquid chromatography–tandem mass spectrometry (LC–MS/MS). Aortic wall samples from 12 patients were analysed for elastic fibre content and MMP expression by histology and western blotting. Statistical analyses included correlation testing, propensity score matching, and receiver operating characteristic (ROC) analysis. TAAA patients exhibited significantly higher pDES levels compared with controls (0.40 ± 0.31 vs. 0.22 ± 0.15 ng/mL; p < 0.001). pDES correlated positively with MMP-2 (ρ = 0.68, p = 0.02), TIMP-1 (ρ = 0.72, p = 0.01), and the proportion of elastic fibres in the aortic media (ρ = 0.61, p = 0.03). ROC analysis showed good diagnostic performance (AUC = 0.82), with a threshold of 0.27 ng/mL yielding 78.6% sensitivity and 76.7% specificity. Elevated pDES levels reflect aortic elastolytic activity and may serve as a promising biomarker for TAAA detection and risk assessment. Full article

This work demonstrates laser-induced breakdown spectroscopy (LIBS) applied to a stream of aerosolized salt from molten eutectic LiCl-KCl. We demonstrate analytical capabilities to track fission-product surrogates of Cs, Sr, Pr, and Nd simultaneously, with application to monitor salts in pyroprocessing schemes and molten salt reactors. This work demonstrates limits of detection using LIBS on the order of 100 $\mathsf{\mu }$g/g, which proves potentially applicable to monitoring fission-product concentrations in pyroprocessing applications. Additionally, this work explores fundamental aspects of plasma temperature and plasma electron density of the aerosolized species during LIBS with a specific focus on potential non-uniform plasma conditions in the aerosol. Full article

Laser-induced breakdown spectroscopy has become a promising method for rapid elemental analysis; however, application of LIBS directly to liquid solutions remains technically challenging due to plasma instability and matrix effects. In this study, a liquid-phase LIBS system featuring sample introduction via a nebulizer-based aerosol was evaluated for direct measurement of lithium in synthetic brine solutions. A synthetic brine sample matrix was prepared by saturating a 1% HNO₃ solution with sodium chloride. The brine was spiked with various analytes at concentrations expected in natural brine solutions of interest for modern industrial purposes, with a focus on Li. Lithium emission at 670.8 nm was clearly detected, with a detection limit of 0.3 mg L⁻¹. An evaluation of calibration strategies, including external calibration, internal standardization, and standard addition, showed that matrix effects significantly impact measurement accuracy, as expected of any analytical instrumentation setup. Incorporation of standard addition allowed for the liquid-phase LIBS system to successfully quantify lithium in synthetic brine solutions without additional sample preparation or dilution. These findings suggest that, with proper sample introduction and calibration, liquid-phase LIBS analysis can be a quick and portable alternative to traditional lab techniques for lithium detection and process monitoring in complex brines. Full article