Search Results (134)

Polyvinyl alcohol/carboxymethyl cellulose (PVA/CMC) blend nanocomposites reinforced with plasma-assisted synthesized zinc oxide–gold (ZnO–Au) nanoparticles were prepared via casting at varying nanoparticle concentrations. Structural and interfacial modifications were analyzed using XRD, FTIR, Raman spectroscopy, and XPS. XRD analysis confirmed the nanocomposite crystallinity, showing an average crystallite size of 24.48 nm and a lattice strain of 4.32 × 10⁻³ for the 0.15 wt% ZnO–Au composite. FTIR and Raman spectra revealed band shifts and broadening, indicating strong interactions between ZnO–AuNPs and the polymer matrix. XPS analysis further verified Zn and Au incorporation and changes in C 1s and O 1s intensities, reflecting modified surface chemistry. Optical analysis revealed a reduction in the band gap from 4.60 eV (pure PVA/CMC) to 3.52 eV for the 0.15 wt% ZnO–Au nanocomposite, accompanied by an increase in refractive index from 2.058 to 2.244, along with enhanced UV-shielding the performance due to reduced UV transmittance and increased film opacity. Thermogravimetric analysis demonstrated enhanced thermal stability, while antibacterial tests against E. coli and S. aureus confirmed strong antimicrobial activity. These findings demonstrate that PVA/CMC/ZnO–Au nanocomposites are a promising candidate for antibacterial, UV-blocking, food packaging, and optoelectronic applications. Full article

Combined pulse laser systems combining continuous-wave (CW) lasers and nanosecond pulsed lasers have shown clear advantages in metal ablation and surface modification. However, the plasma shielding effect induced by nanosecond pulses and the associated shock-wave phenomena in hybrid laser systems remain insufficiently investigated, particularly regarding their influence on CW laser energy coupling. In this study, the ablation behavior of metal targets under the combined irradiation of a 500 W CW laser and nanosecond pulsed lasers with pulse energies ranging from 0.4 J to 1.0 J was investigated. High-speed plasma imaging was employed to analyze laser–material interaction characteristics, including absorption behavior and molten material ejection, while high-speed infrared thermography was used to monitor transient temperature evolution during combined pulse laser processing. Macroscopic and microscopic analyses were conducted to characterize damage morphology, and a three-dimensional surface profilometer was used to quantitatively evaluate ablation efficiency. The results show that, under combined pulse laser irradiation, the removed volume increased from 0.05 mm³ to 0.618 mm³ and the ablation depth increased from 0.136 mm to 0.776 mm. Compared with CW laser processing alone, the ablation efficiency was markedly enhanced. This improvement is attributed to the combined effects of optimized energy deposition, thermal distribution, and material response. In addition, the plasma shielding effect was observed to vary with nanosecond pulse energy, indicating that precise energy control is critical for performance enhancement. This study demonstrates the potential of combined pulse laser technology for high-efficiency and high-precision metal surface processing and micro–nano fabrication. Full article

To address poor wear resistance of surface metal grids for optical windows and low efficiency and poor uniformity of traditional embedded technologies, this study fabricates ultra-wear-resistant embedded metal grids on 180 mm × 180 mm × 8 mm sapphire via photolithography and large-area plasma etching. Etching grooves (depth about 300 nm) and depositing 135 nm silver (Ag) + 170 nm alumina (Al₂O₃) films, the grids exhibit transmittance 80.2%~80.9% (2~5 μm), wear resistance without damage, and reliable EMI shielding (Electromagnetic Interference Shielding) (3~18 GHz), offering a scalable solution for harsh-environment optoelectronic windows. The embedded structure integrates high transmittance, ultra-wear resistance, and reliable EMI shielding, addressing the core demands of optoelectronic windows in aerospace, outdoor monitoring, and other harsh environments where durability and stability are critical. The key innovation lies in the optimized integration of large-area plasma etching and low-temperature electron beam deposition, achieving precise control of groove depth uniformity (<4%) and transmittance uniformity (<1%) on high-hardness sapphire substrates, which overcomes the trade-off between efficiency and uniformity in traditional embedded technologies. Future applications include high-performance optical windows for airborne surveillance systems, space-borne optoelectronic devices, and harsh-environment industrial monitoring equipment, with potential extension to other high-hardness dielectric substrates. Full article

Debye shielding in an electron–ion plasma with regularized kappa distribution is examined. An unmagnetized collisionless plasma sheath with regularized kappa distributed electrons is investigated and the modified Bohm criterion is derived. It is found that the variation of the electrostatic potential depends significantly on the superthermal index κ and cutoff parameter α. If κ < 3/2, a plasma sheath with a regularized kappa distribution exists. Our present work may be useful in understanding plasma processing and plasma sheaths in related plasma regions (i.e., Earth’s inner magnetosphere). Full article

The increasing threat posed by micrometeoroids and orbital debris to in-orbit spacecraft necessitates the development of lightweight and deformable shielding systems capable of withstanding hypervelocity impacts. Ultra-high-molecular-weight polyethylene (UHMWPE) films, owing to their high specific strength and energy-absorption capacity, present a promising candidate for such applications. However, the hypervelocity impact response of thin, highly oriented UHMWPE films—distinct from bulk plates or composites—remains poorly understood, particularly for micron-scale particles at velocities relevant to space debris (≥8 km/s). In this study, we systematically investigate the impact resistance of 0.1 mm UHMWPE films using a plasma-driven microparticle accelerator and a hypervelocity dust gun to simulate impacts by micron-sized Al₂O₃ and Fe particles at velocities up to ~8.5 km/s. Through detailed analysis of crater morphology via scanning electron microscopy, we identify three distinct damage modes: plastic-dominated craters (Type I), fracture-melting craters (Type II), and perforations (Type III). These modes are correlated with impact energy and particle size, revealing the material’s transition from large-scale plastic deformation to localized thermal softening and eventual penetration. Crucially, we provide quantitative penetration thresholds (e.g., 2.25 μm Al₂O₃ at 8.5 km/s) and establish a microstructure-informed damage classification that advances the fundamental understanding of UHMWPE film behavior under extreme strain rates. Our findings not only elucidate the energy-dissipation mechanisms in oriented polymer films but also offer practical guidelines for the design of next-generation, flexible spacecraft shielding systems. Full article

Ultra-precision single-point diamond turning (SPDT) remains the core process for fabricating optical-grade surfaces with nanometric roughness and sub-micrometer form accuracy. However, machining hard-to-cut or brittle materials such as high-entropy alloys, metals, ceramics, and semiconductors is limited by severe tool wear, high cutting forces, and brittle fracture. To overcome these challenges, a new generation of non-conventional assisted and hybrid SPDT platforms has emerged, integrating multiple physical fields, including mechanical, thermal, magnetic, chemical, or cryogenic methods, into the cutting zone. This review comprehensively summarizes recent advances in hybrid non-conventional assisted SPDT platforms that combine two or more assistive techniques such as ultrasonic vibration, laser heating, magnetic fields, plasma or gas shielding, ion implantation, and cryogenic cooling. The synergistic effects of these dual-field platforms markedly enhance machinability, suppress tool wear, and extend ductile-mode cutting windows, enabling direct ultra-precision machining of previously intractable materials. Recent key case studies are analyzed in terms of material response, surface integrity, tool life, and implementation complexity. Comparative analysis shows that hybrid SPDT can significantly reduce surface roughness, extend diamond tool life, and yield optical-quality finishes on hard-to-cut materials, including ferrous alloys, composites, and crystals. This review concludes by identifying major technical challenges and outlining future directions toward optimal hybrid SPDT platforms for next-generation ultra-precision manufacturing. Full article

Intracellular targeting is the missing dimension in contemporary oncology, and nanosecond pulsed electric fields (nsPEFs) uniquely aim to deliver it. By charging membranes on sub-microsecond timescales, nsPEF bypasses plasma-membrane shielding to porate organelles, collapse mitochondrial potential, perturb ER calcium, and transiently open the nuclear envelope. This mechanism reprograms malignant fate while preserving tissue architecture. This review synthesizes the most recent evidence to frame nsPEF as a programmable intracellular therapy, mapping mechanistic design rules that link pulse width, amplitude, repetition, and rise time to specific organelle responses. We outline therapeutic applications, including the induction of apoptosis in resistant tumors, immunogenic cell death with systemic memory, and synergy with checkpoint blockade. We also survey integrations with nanoparticles, calcium, and chemotherapeutic drugs for improved outcomes. We critically appraise safety, selectivity, and scalability, distill translational bottlenecks in dosimetry and standardization, and propose an actionable roadmap to accelerate clinical adoption. Viewed through this lens, nsPEF is not merely another ablation tool but a platform for precision intracellular oncotherapy, capable of drug-sparing efficacy and immune convergence when engineered with rigor. Full article

Laser-induced breakdown spectroscopy (LIBS), limited by matrix effects, self-absorption in complex samples, and ambient atmospheric influences, still requires further improvement in detection sensitivity and signal stability. In this work, the excitation beam of LIBS is modulated into an optical vortex by an optical phase element, and optical vortex-induced LIBS is used to detect and analyze coal samples. Building on the uniform annular intensity distribution and orbital angular momentum (OAM) carried by the optical vortex, it is anticipated that spectral signal intensity can be enhanced by improving plasma ablation efficiency, reducing shielding effects, and increasing electron collision frequency, thereby reducing signal uncertainty and enhancing LIBS analytical performance. For the first time, a classification model combining principal component analysis (PCA) and support vector machine (SVM) is developed, integrating optical vortex-induced LIBS technology with machine learning. Using the PCA-SVM model, optical vortex-based LIBS attained a coal classification accuracy of 95%, significantly higher than the 88% achieved with Gaussian beams, thereby markedly improving classification performance for complex matrix samples. These results demonstrate that optical vortex-induced LIBS possesses strong potential for efficient detection of samples with complex matrices. Full article

Al-W composites are lightweight, high-strength, structural–functional integrated materials with tailorable density and excellent X/γ-ray shielding performance, making them promising candidates for nuclear and aerospace applications. In this study, high-W-content 2024Al-W composites were successfully fabricated via spark plasma sintering (SPS) at a relatively low temperature of 440–500 °C. With increasing sintering temperature, the relative density of the composites increased from 99.6% to 99.9%. A ternary intermetallic compound, Al₁₈Mg₃W₂, was first detected at the Al/W interface at 460 °C. At 480 °C, submicrometre Al₁₈Mg₃W₂ phases formed and cooperated with nanoscale Al₂Cu precipitates, effectively enhancing interfacial bonding and optimizing mechanical properties—yielding an ultimate tensile strength of 266.9 MPa and an elongation of 6.2%. Among the strengthening mechanisms, coefficient of thermal expansion (CTE) mismatch strengthening contributed the most (~19.2 MPa), followed by load transfer (~4.27 MPa) and Orowan strengthening (~1.17 MPa). These findings provide valuable insights into the low-temperature preparation of high-W-content Al-W structural–functional materials via SPS. Full article

Therapeutics involving small interfering RNA (siRNA) have enormous potential for treating a number of diseases, but their effective delivery to target cells remains a major challenge. We studied the influence of the structure and combination of targeted (folate conjugated, F13) and shield lipoconjugates (P1500, diP1500) on the ability of cationic liposomal formulations based on the 2X3-DOPE system to deliver siRNA into cells in vitro and in vivo. The loop-structured PEG lipoconjugate equipped with two hydrophobic anchor groups (diP1500) demonstrated superior performance across multiple evaluation criteria. The F13/diP1500 composition maintained a compact particle size (126.0 ± 23.0 nm), while F13/P1500 with the same PEG chain equipped with one anchor group maintained an increased particle size of 241.8 ± 65.7 nm. Most critically, F13/diP1500 preserved substantial positive surface charges (21.6–30.5 mV) across all N/P ratios, demonstrating superior ability in avoid the “PEG dilemma”, whereas F13/P1500 suffered substantial charge neutralization (3.9–9.1 mV). Competitive inhibition with free folate confirmed receptor-mediated cellular accumulation of siRNA mediated by F13 containing liposomal compositions. In vivo biodistribution revealed statistically significant circulation advantages: DSPE-PEG2000/diP1500 achieved the highest plasma concentration at 15 min (1.84 ± 0.01 pmol/mL), representing the first direct in vivo comparison of compositions with PEG lipoconjugates of the same length, but formed different structures in the liposomes due to the presence of one or two anchor groups. Our findings provide critical insights for the rational design of targeted liposomal delivery systems, highlighting the importance of balanced optimization between folate targeting functionality and PEG shielding for effective siRNA delivery both in vitro and in vivo. Full article

Abiotic stresses severely impair plant growth and productivity. To counteract stress, plants have evolved intricate strategies, including the induction of stress-responsive proteins. The Arabidopsis thaliana Salt Tolerance-Related Protein (STRP) has recently emerged as a key player in abiotic stress tolerance. STRP is a small, hydrophilic, intrinsically disordered protein that exhibits the potential to adopt distinct conformations depending on the cellular context. STRP is localized in the cytosol and nucleus and is associated with the plasma membrane. Stress induces the subcellular redistribution of STRP, accompanied by a significant increase (up to ten-fold) in its levels due to reduced degradation by the 26S proteasome. Reverse genetics studies have demonstrated that STRP can mitigate the detrimental effects of oxidative stress and participate in modulating stress-related gene expression. Although the exact mechanism of STRP remains unclear, its physicochemical properties suggest a dual role as a molecular shield, interacting with macromolecules without a fixed conformation, and as a binder of specific defense-related client proteins, adopting a defined tertiary structure. This review provides a comprehensive overview of STRP and its emerging role as a multifunctional player in abiotic stress responses, also highlighting its potential for strengthening crop resilience and maintaining agricultural productivity under global climate challenges. Full article

Organ-on-a-chip (OoC) technology aims to replicate the functions of human organs and tissues. This study evaluates femtosecond laser micromachining (FLM) for producing PDMS membranes with controlled porosity as an alternative approach to conventional microfabrication for OoCs. Membranes of varying thicknesses were microdrilled, and the influence of laser parameters on microhole geometry was assessed, showing that pulse energy strongly affected hole diameter, whereas exposure time had a lesser impact. The heat-affected zone (HAZ) and taper angle, key indicators of microhole geometric quality, were also analyzed and found to be strongly dependent on membrane thickness. Prediction models were developed to guide parameter selection for future laser-based ablation processes. A numerical model that predicts plasma shielding effects provided further insight into the physics of PDMS laser ablation, revealing that higher pulse energies led to a marked increase in crater diameter. The fabricated membranes were integrated into an OoC device, onto which human mesenchymal stem cells were seeded. The results demonstrated strong cell adhesion, the rapid formation of a homogeneous monolayer, and no evidence of cytotoxicity. These findings confirm that FLM is a versatile and flexible technique for microdrilling PDMS membranes, enabling their effective integration into OoC. Full article

During the laser cladding process, the temperature, flow velocity, and element concentration of the molten pool will be affected by the plasma. Quantitative analysis of the mechanism by which the plasma affects heat and mass transfer during the laser cladding process is of great significance for improving the quality of the cladding layer. In this paper, a multi-field coupled numerical model of the laser cladding process of Fe60 using an ASTM 1045 disk laser was established. In the modeling, the interaction between the plasma cloud and the laser beam (the ionization process of metal vapor absorbing photon energy and the absorption and shielding effect of the plasma on laser energy), as well as the influence of surface tension, buoyancy, and shock waves generated by the expansion of the plasma cloud on the Marangoni flow of the liquid metal, was considered. A comparative analysis was performed on the transient evolution of the temperature field, flow field, and concentration field during the laser cladding process in the presence of the plasma cloud. The results show that the ionization process of metal vapor and the shielding effect of the plasma cloud cause a decrease in laser energy and the temperature of the cladding layer. The Marangoni flow is affected by the shock waves generated by the expansion of the plasma cloud, resulting in a decrease in the flow velocity of the melt. A slight decrease in the concentration of Fe, Cr, and Ni elements and a slight increase in the concentration of C element in the cladding layer are caused by melt evaporation. Full article

Disulfiram (DSF), a well-known anti-alcoholism drug, exhibits potent anticancer activity via its metabolite, diethyldithiocarbamate (DDC), which forms a cytotoxic copper complex that selectively targets cancer stem cells. However, its clinical utility is limited by poor solubility and rapid plasma metabolism. This study explores saccharide-linked DDCs as novel prodrugs designed to enhance stability, solubility, and tumour-selective activation. These compounds feature thioglycosidic bonds that shield the DDC moiety from premature degradation while retaining its metal-chelating function to form the active copper(II)bis(N,N-diethyldithiocarbamate) (Cu(DDC)₂) complex. The synthesised derivatives were characterised and evaluated for serum stability and in vitro cytotoxicity across several cancer cell lines, including colorectal, breast, lung, and brain cancers. Copper-complexed saccharide-DDC prodrugs demonstrated remarkable cytotoxicity, with improved biostability and solubility profiles. These findings highlight the potential of saccharide-linked DDCs as stable, copper-activated prodrugs for cancer therapy. Further in vivo studies are warranted to validate their pharmacokinetics and clinical relevance. Full article

Glass-based microfluidic devices are essential for applications such as diagnostics and drug discovery, which utilize their optical clarity and chemical stability. This review systematically analyzes pulsed laser micromachining as a transformative technique for fabricating glass-based microfluidic devices, addressing the limitations of conventional methods. By examining three pulse regimes—long (≥nanosecond), short (picosecond), and ultrashort (femtosecond)—this study evaluates how laser parameters (fluence, scanning speed, pulse duration, repetition rate, wavelength) and glass properties influence ablation efficiency and quality. A higher fluence improves the material ablation efficiency across all the regimes but poses risks of thermal damage or plasma shielding in ultrashort pulses. Optimizing the scanning speed balances the depth and the surface quality, with slower speeds enhancing the channel depth but requiring heat accumulation mitigation. Shorter pulses (femtosecond regime) achieve greater precision (feature resolution) and minimal heat-affected zones through nonlinear absorption, while long pulses enable rapid deep-channel fabrication but with increased thermal stress. Elevating the repetition rate improves the material ablation rates but reduces the surface quality. The influence of wavelength on efficiency and quality varies across the three pulse regimes. Material selection is critical to outcomes and potential applications: fused silica demonstrates a superior surface quality due to low thermal expansion, while soda–lime glass provides cost-effective prototyping. The review emphasizes the advantages of laser micromachining and the benefits of a wide range of applications. Future directions should focus on optimizing the process parameters to improve the efficiency and quality of the produced devices at a lower cost to expand their uses in biomedical, environmental, and quantum applications. Full article