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Stereotactic laser interstitial thermal therapy for brainstem cavernous malformations: two preliminary cases
摘要： Brainstem cavernous malformations (CMs) often have high hemorrhage rates and significant posthemorrhage morbidity. The authors present two cases in which magnetic resonance thermography-guided laser interstitial therapy was used for treatment of pontine CMs after recurrent hemorrhage. Both patients showed significant symptomatic improvement and were hemorrhage-free at 12- and 6-month follow-up, respectively. Each had radiographic evidence of lesion involution on serial follow-up imaging. These early results demonstrate this treatment modality may be technically safe; however, larger case numbers and longer follow-up are needed to demonstrate efficacy.
关键词： Cavernous malformation,Cavernoma,Magnetic resonance imaging,Thermometry,Brainstem,Laser interstitial thermal therapy,Minimally invasive,Stereotactic laser ablation
更新于2025-09-23 15:21:01
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Gas-Phase Formation of Highly Luminescent 2D GaSe Nanoparticle Ensembles in a Nonequilibrium Laser Ablation Process
摘要： Interest in layered two-dimensional (2D) materials has been escalating rapidly over the past few decades due to their promising optoelectronic and photonic properties emerging from their atomically thin 2D structural confinements. When these 2D materials are further confined in lateral dimensions toward zero-dimensional (0D) structures, 2D nanoparticles and quantum dots with new properties can be formed. Here, we report a nonequilibrium gas-phase synthesis method for the stoichiometric formation of gallium selenide (GaSe) nanoparticles ensembles that can potentially serve as quantum dots. We show that the laser ablation of a target in an argon background gas condenses the laser-generated plume, resulting in the formation of metastable nanoparticles in the gas phase. The deposition of these nanoparticles onto the substrate results in the formation of nanoparticle ensembles, which are then post-processed to crystallize or sinter the nanoparticles. The effects of background gas pressures, in addition to crystallization/sintering temperatures, are systematically studied. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectroscopy, and time-correlated single-photon counting (TCSPC) measurements are used to study the correlations between growth parameters, morphology, and optical properties of the fabricated 2D nanoparticle ensembles.
关键词： laser-based synthesis,2D materials,2D quantum dots,2D nanoparticles,laser ablation
更新于2025-09-23 15:21:01
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Comparison Between Minimal Fluoroscopy and Conventional Approaches for Visually Guided Laser Balloon Pulmonary Vein Isolation Ablation
摘要： Introduction: Although balloon-based techniques such as the laser balloon (LB) ablation have simplified pulmonary vein isolation (PVI), procedural fluoroscopy usage remains higher in comparison to radiofrequency PVI approaches due to limited 3-dimensional mapping system integration. Methods: In this prospective study, 50 consecutive patients were randomly assigned in alternating fashion to a low fluoroscopy group (LFG, n=25) or conventional fluoroscopy group (CFG, n=25) and underwent de novo PVI procedures using visually guided LB technique. Results: There was no statistical difference in baseline characteristics or cross-overs between treatment groups. Acute PVI was accomplished in all patients. Mean follow up was 318 ± 69 days. Clinical recurrence of AF after PVI was similar between groups (CFG: 19% vs LFG: 15%; p=0.72). Total fluoroscopy time was significantly lower in the LFG than the CFG (1.7 ± 1.4 min vs. 16.9 ± 5.9 min; p < 0.001) despite similar total procedure duration (143 ± 22 min vs. 148 ± 22 min; p= 0.42) and mean LA dwell time (63 ± 15 min vs. 59 ± 10 min; p=0.28). Mean DAP was significantly lower in the LFG (181 ± 125 μGym2 vs. 1980 ± 750 μGym2; p < 0.001). Fluoroscopy usage after transseptal access was substantially lower in the LFG (0.63 ± 0.43 min vs. 11.70 ± 4.32 min; p < 0.001). Complications rates were similar between both groups (4% vs. 2%; p=0.57). Conclusions: This study demonstrates that LB PVI can be safely achieved using a novel low fluoroscopy protocol while also substantially reducing fluoroscopy usage and radiation exposure in comparison to conventional approaches for LB ablation.
关键词： Atrial fibrillation,laser balloon,low fluoroscopy,fluoroless,pulmonary vein isolation,laser ablation
更新于2025-09-23 15:21:01
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Multipulse laser ablation of BiSn eutectic: Noncongruent element transfer and morphology analysis
摘要： The surface of a eutectic BiSn target was ablated by several series of pulses at different spots using an excimer laser with a wavelength of 351 nm and a pulse duration of 20 ns. Morphology of ablation craters formed under a different number of pulses was analyzed with a scanning electron microscope, an optical profilometer, and an energy dispersion spectroscope (EDS). Laser-induced breakdown spectroscopy (LIBS) measurements were taken for each crater with the last pulse in the series of pulses. The ratio of peak intensities (Bi I peak at 472.25 nm and Sn I 563.16 nm) of LIBS spectra for craters formed by different series of pulses decreased from maximum at a single pulse to a stable magnitude after a series of 70 pulses. EDS mapping of crater areas for different series of pulses shows a decrease in Bi atoms abundance, in correlation with the decrease in normalized intensity of Bi peak LIBS spectra. The change of the chemical composition in the ablation area is explained based on the Knudsen evaporation model. For the first time, pronounced hydrodynamic effects resulting in the formation of 50 μm-high rims were observed. The unusual morphology of the ablated area is explained on the basis of hydrodynamic effects and recoil pressure.
关键词： LIBS,BiSn eutectic,laser ablation,EDS,SEM
更新于2025-09-23 15:21:01
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Pulsed laser ablation route assisted copper oxide nanoparticles doped in Polyethylene Oxide/Polyvinyl pyrrolidone blend for enhancement the electrical conductivity
摘要： Polyethylene Oxide/Polyvinyl pyrrolidone blend was doped by Copper Oxide Nanoparticles (CuONPs) prepared by laser ablation process. Synthesized Copper oxide nanoparticles were prepared by ablating pure copper plate immersed in DDW by nanosecond Nd:YAG laser in different times. PEO/PVP/CuONPs nanocomposites have been synthesized via casting technique. Effect of CuONPs doping on enhancing PEO/PVP have been obtained. The influence of various times of laser ablation on the properties of the synthesized nanocomposite films was analyzed via several techniques. SEM and XRD proved the interaction between PEO/PVP blend and CuONPs. The presence of the distinctive absorption peak at UV-Vis range at 277 nm was due to copper oxide surface plasmon resonance (SPR). The direct and indirect optical band gap values illustrate a decrease following doping of copper oxide inside PEO/PVP matrix. Dielectric constant and dielectric loss activity gradually diminished as the frequency rises. AC conductivity were increased as laser time increased.
关键词： Copper oxide nanoparticles,Pulsed laser ablation,Ac conductivity,PEO/PVP
更新于2025-09-23 15:21:01
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Preparation and Characterization of Metal-Organic Frameworks and its Composites Eu <sub/>2</sub> O <sub/>3</sub> @[Zn <sub/>2</sub> (bdc) <sub/>2</sub> dabco] (ZBDh) via Pulsed Laser Ablation in Flow Liquid
摘要： This work reports the compounds of [Zn2(bdc)2dabco] (ZBDh) and [Zn2(bdc)2dabco] (ZBDt) and the composite Eu2O3@[Zn2(bdc)2dabco](ZBDh) synthesized by pulsed laser ablation in flowing liquid. At an appropriate reactants concentration of reactants, the phase ZDBh transforms into phase ZDBt by an increase of the irradiation time from 4 to 40 mins. The results show that the Eu2O3 nanoparticles with an average size of 3.17 nm are uniformly distributed among the crystal and the BET specific surface area of the composite Eu2O3@[Zn2(bdc)2dabco] (ZBDh) is 1621 m2/g, which is larger than that of compound [Zn2(bdc)2dabco] (ZBDh). Moreover, the composite Eu2O3@[Zn2(bdc)2dabco](ZBDh) can emit very intense characteristic fluorescence at 613 nm of Eu3+ ion under ultraviolet radiation and can be used for detecting of methanol molecules in fluorescence sensing because of its fluorescence intensity at 613 nm is sensitive to the content of methanol in solvent.
关键词： pulsed laser ablation,metal-organic frameworks,Eu2O3 nanoparticles,fluorescence sensing,methanol detection
更新于2025-09-23 15:21:01
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Antibacterial activity of Fe-doped ZnO nanoparticles synthesised via pulsed laser ablation in liquid against <i>Staphylococcus Aureus</i>
摘要： Pulse laser ablation in liquid (PLAL) technique has been performed in pure water as the solution to produce ZnO and Fe-doped ZnO nanoparticles, by varying Fe ablation time 5, 10 and 15 min. The characterisation was carried out using UV–vis spectrometer, photoluminescence 325 spectrometer, X-Ray diffraction, and high resolution-transmission electron microscopy (HR-TEM). The band gap energy was found to be 3.18 eV for pure ZnO and it was decreased down to 2.86 eV for ZnO for the highest Fe concentration. The shape and size, which were obtained from TEM, showed no significant change of ZnO nanoparticles with and without Fe addition. All samples were tested to inactivate Staphylococcus aureus (S. aureus) growth, which shows promising antibacterial properties as they are able to inactivate bacteria under normal ambient laboratory light, especially Fe-doped ZnO which is able to reduce more bacteria than pure ZnO.
关键词： ZnO,antibacterial,Fe-ZnO,nanoparticles,laser ablation
更新于2025-09-23 15:21:01
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Comparison of quantitative analyses using SIMS, atom probe tomography, and femtosecond laser ablation inductively coupled plasma mass spectrometry with Si <sub/>1a??X</sub> Ge <sub/>X</sub> and Fe <sub/>1a??X</sub> Ni <sub/>X</sub> binary alloys
摘要： Due to their electrical and physical properties, Si1?XGeX materials are widely used in microelectronic devices. In particular, the Ge component found within Si1?XGeX compounds is important for enhancing carrier mobility and altering the lattice constant of metal-oxide-semiconductor field-effect transistors. In this study, magnetic sector secondary ion mass spectrometry (magnetic sector SIMS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used to determine the accurate concentrations of major compositions present within binary alloy samples. However, quantitative SIMS analysis is limited by the matrix effect, which influences the sputter yield of an element in a compound and alters the secondary ionization yields. Quantitative deviations that were due to the matrix effect were reduced by using Cs cluster ions (MCs+ and MCs2+) instead of elemental ions; the SIMS results using the elements were, therefore, compared with those using MCs+ and MCs2+ cluster ions. In the case of Fe1?XNiX alloys that have a less matrix effect compared to Si1?XGeX alloys, both the Cs primary ion beam (Cs+) and an oxygen primary ion beam (O2+) were used to measure the Fe1?XNiX compositions. The quantitative results from the two different primary ion beams were then compared to understand the ionization process. Deviations in the quantitative values gained with the O2+ beam were lower than those obtained using the Cs+ primary ions, meaning that using oxygen as the primary ion improves the accuracy in quantifying Fe1?XNiX compounds. Other reliable tools for analysis such as atom probe tomography and femtosecond laser ablation inductively coupled plasma mass spectrometry were also used in the quantitative analysis, with results that were consistent with the most accurate results obtained using magnetic sector SIMS and ToF-SIMS.
关键词： Si1?XGeX,femtosecond laser ablation inductively coupled plasma mass spectrometry,atom probe tomography,SIMS,Fe1?XNiX,binary alloys
更新于2025-09-23 15:21:01
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Laser Ablation of Stainless Steel in Water and Hexane: Characterization of Surface Modification and Nanoparticles for Various Applications
摘要： This work investigates the effect of a liquid medium on the roughness and the chemical composition of an ablated, stainless steel target, as well as on various properties of the laser-generated nanoparticles, such as absorption, hardness, and yield; in addition, some possible applications of laser ablation in both water and hexane are suggested. It is found that changing the liquid medium from hexane to distilled water not only changes the chemical composition of the target, but also reduces the mass ejected from the target by roughly 25%. Further, this change leads to a “smoother” ablation process and reduces the roughness of the target. Finally, mixed results were obtained when changing the liquid medium. Nanoparticle properties such as yield and absorption were found to be greatly affected, while mechanical properties, such as hardness, are not dependent on the liquid medium.
关键词： confined plasma,nanohardness,stainless steel,laser ablation in liquid,surface roughness
更新于2025-09-23 15:21:01
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Application Laser Transfer of Metal Nanoparticles to Bacterial Biofilms
摘要： The method of application laser transfer of silver and copper nanoparticles for the first time has been shown to be effective against biofilms formed on a solid substrate. It has been experimentally confirmed that this effect is not associated with the influence of the laser itself. The proposed method allows one to increase the locality, availability, and efficiency of biofilm destruction due to the bactericidal effect of metal nanoparticles with a slight direct laser effect on the biofilm.
关键词： metal nanoparticles,laser ablation,bacterial biofilms
更新于2025-09-23 15:21:01