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Germanium catalyzed vapor–liquid–solid growth and characterization of amorphous silicon oxide nanotubes: comparison to the growth of its nanowires
摘要： One-dimensional (1D) nanostructures were grown with a simple technique using continuous-wave laser vaporization of a Ge target containing 5 at.% Si in high-pressure (up to 0.9 MPa) Ar gas atmosphere. A maximum amount (~ 30% of all products) of 1D nanostructures was obtained at 0.9 MPa and these nanostructures were identified as amorphous silicon oxide (SiOx) nanotubes (NTs) and attached with crystalline Ge-rich NPs with elongated prolate-like or sphere-like shapes at their tips by transmission electron microscopy (TEM), high-angle annular dark-field-scanning TEM, and energy dispersive X-ray line scan spectrometry. As the Ar pressure decreased from 0.9 to 0.03 MPa, the average diameters, wall thicknesses, and lengths of the NTs decreased from 57.9 to 22.9 nm, 13.2 to 6.7 nm, and 2.1 to 0.2 μm, respectively, and the tip NP size decreased from 139.0 to 41.7 nm. There was a strong correlation among the diameters, wall thicknesses, and lengths of the NTs and tip Ge NP sizes, indicating the role of molten Ge NPs as catalyst seeds for the precipitation of SiOx in a vapor–liquid–solid growth mechanism at high temperature. The SiOx precipitation quantities from the seed NPs for the NTs were compared with those of amorphous SiOx nanowires (NWs) at 0.1–0.9 MPa to clarify the growth mechanism of the NTs. We argue that smaller precipitation quantities of SiOx than those for the NWs play a critical role in the formation of cap structures with different sizes and shapes from the molten Ge NPs and the growth of the NTs.
关键词： Laser vaporization,Germanium catalyst,Silicon oxide,Nanotube,Nanowire
更新于2025-09-23 15:23:52
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Local Vaporization at the Cut Front at High Laser Cutting Speeds
摘要： High-speed videos of the cut front and spectrometric measurements were applied to detect local vaporization on the cut front at high cutting speeds to show that with increasing feed rate, temporally short and intense flashes are generated by vaporization phenomena on the upper part of the cut front. The latter are accompanied by the emergence of an interrupted striation pattern on the surface of the cutting edge. The findings support the assumption that local vaporization at the cut front might be the cause for reduced quality of the cutting process at elevated cutting speeds. The observation of vaporization serves as a diagnostic method to anticipate a fail cut and the interrupted striation pattern.
关键词： Laser cutting,Vaporization,Interrupted striations,Camera observation,Spectral emission
更新于2025-09-23 15:21:01
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Luminescence of monoclinic Y2O3:Eu nanophosphor produced via laser vaporization
摘要： Europium doped Y2O3spherical nanoparticles with the diameter ~10 nmobtained via cw laser vaporization are shown to crystallize in monoclinic symmetry class (C2/m space group). The size of nanoparticles established via HRTEM coincides with coherent scattering region established by XRD. Luminescence spectrum in the vicinity of ultranarrow transition demonstrates three peaks consistent with three inequivalent positions of Eu3t ion in monoclinic Y2O3 lattice. Hypersensitive transition dominates in the spectrum, admitting the lack of inversion symmetry at Cs sites occupied by Eu3t. The spectrum of hypersensitive transition is expanded to the red part of spectrum due intense transitions terminating at higher-lying components of crystal-field-split 7F2 energy level. Obtaining chromaticity coordinates (0.669, 0.331)and absolute quantum yield (~21%) is possible using red phosphor based on monoclinic Y2O3:Eu3t.
关键词： Laser vaporization,Monoclinic Y2O3:Eu nanophosphor,Photoluminescence of Eu3t
更新于2025-09-23 15:21:01
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GREEN LIGHT PHOTOSELECTIVE VAPORIZATION OF THE PROSTATE: ONE LASER FOR DIFFERENT PROSTATE SIZES
摘要： INTRODUCTION GreenLight laser vaporization of the prostate (PVP) is a safe and effective procedure for Benign Prostatic Hyperplasia. Long term results and advantages of PVP in patients with large and symptomatic prostate are still under evaluation. MATERIALS AND METHODS In a multicenter experience, patients who underwent standard or anatomical PVP were retrospectively reviewed. Patients with follow-up >12 months were divided into two groups based on prostate volume (<100cc vs ≥100cc). Pre- and peri-operative data as well as post-operative results and complications were recorded after 3, 6, 12 months and then annually. RESULTS 1031 patients were eligible, 916 of these had a prostate volume of <100 cc and 115 ≥100 cc. Median follow-up period was 25.0 months (IQR 16.5-35.0) and 16.0 months (IQR 12.0-24.0) in ≥100 and <100 groups, respectively. No difference was found in terms of catheterization time, post-operative stay and post-operative acute urine retention. Patients with prostate ≥100 required longer operative time (75 versus 55 minutes), lasing time (41.7 versus 24.9 minutes), and higher energy used but lower energy density. Patients with prostate ≥100 had a higher incidence of early (50.4 versus 35.7%) and late complications (21.7 versus 12.8%) and early urge/incontinence symptoms (40.9 versus 29.3%). No statistically significant differences were found for the Qmax and IPSS results between the two groups. The re-intervention rate in ≥100 group was 3.5% versus 2.3% in <100. CONCLUSIONS In the midterm follow-up, Greenlight PVP guarantees the same results in different prostate volumes groups. Early and late complications are more frequent in large prostates.
关键词： complications,photoselective vaporization of the prostate,prostate volume,benign prostatic hyperplasia,GreenLight laser
更新于2025-09-23 15:19:57
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Optimising patient outcomes with photoselective vaporization of the prostate (PVP): a review
摘要： Benign prostatic hyperplasia (BPH) is a common pathology causing lower urinary tract symptoms (LUTS) and may significantly impact quality of life. While transurethral resection of the prostate (TURP) remains the gold standard treatment, there are many evolving technologies that are gaining popularity. Photoselective vaporization of the prostate (PVP) is one such therapy which has been shown to be non-inferior to TURP. We aimed to review the literature and discuss factors to optimise patient outcomes in the setting of PVP for BPH. A comprehensive search of the electronic databases, including MEDLINE, Embase, Web of Science and The Cochrane Library was performed on articles published after the year 2000. After exclusion, a total of 38 papers were included for review. The evolution of higher powered device has enabled men with larger prostates and those on oral anticoagulation to undergo safely and successfully PVP. Despite continued oral anticoagulation in patients undergoing PVP, the risk of bleeding may be minimised with 5-Alpha Reductase Inhibitor (5-ARI) therapy however further studies are required. Pre-treatment with 5-ARI’s does not hinder the procedure however more studies are required to demonstrate a reliable benefit. Current data suggests that success and complication rate is largely influenced by the experience of the operator. Post-operative erectile dysfunction is reported in patients with previously normal function following PVP, however those with a degree of erectile dysfunction pre-operatively may see improvement with alleviation of LUTS.
关键词： sexual function,outcomes,urinary function,Benign prostatic hyperplasia (BPH),prostate,photoselective vaporization of the prostate (PVP)
更新于2025-09-19 17:15:36
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Comparison of photoselective green light laser vaporisation versus traditional transurethral resection for benign prostate hyperplasia: an updated systematic review and meta-analysis of randomised controlled trials and prospective studies
摘要： Objective To assess the efficacy and safety of green-light laser photoselective vaporisation of the prostate (PVP) compared with transurethral resection of the prostate (TURP) for lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH). Design Systematic review and meta-analysis, conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement. Data sources PubMed, EMBASE, the Cochrane Library until October 2018. Eligibility criteria Randomised controlled trials and prospective studies comparing the safety and efficacy of PVP versus TURP for LUTS manifesting through BPH. Data extraction and synthesis Perioperative parameters, complications rates and functional outcomes including treatment-related adverse events such as International Prostate Symptom Score (IPSS), maximum flow rate (Qmax), postvoid residual (PVR), quality of life (QoL) and International Index of Erectile Function (IIEF). results 22 publications consisting of 2665 patients were analysed. Pooled analysis revealed PVP is associated with reduced blood loss, transfusion, clot retention, TUR syndrome, capsular perforation, catheterisation time and hospitalisation, but also with a higher reintervention rate and longer intervention duration (all p<0.05). No significant difference in IPSS, Qmax, QoL, PVR or IIEF at 3, 24, 36 or 60 months was identified. There was a significant difference in QoL at 6 months (MD=?0.08; 95% CI ?0.13 to ?0.02; p=0.007), and IPSS (MD = ?0.10; 95% CI ?0.15 to ?0.05; p<0.0001) and Qmax (MD=0.62; 95% CI 0.06 to 1.19; p=0.03) at 12 months, although these differences were not clinically relevant. Conclusion PVP is an effective alternative, holding additional safety benefits. PVP has equivalent long-term IPSS, Qmax, QoL, PVR, IIEF efficacy and fewer complications. The main drawbacks are dysuria and reintervention, although both can be managed with non-invasive techniques. The additional shortcoming is that PVP does not acquire histological tissue examination which removes an opportunity to identify prostate cancer.
关键词： PVP,transurethral resection of the prostate,benign prostatic hyperplasia,photoselective vaporization of the prostate,BPH,green-light laser,vaporization,TURP
更新于2025-09-19 17:13:59
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Randomized Trial Comparing Bipolar Transurethral Vaporization of the Prostate versus GreenLight Laser (XPS-180Watt) Photoselective Vaporization of the Prostate for Treatment of small to moderate Benign Prostatic Obstruction: Two-years Outcome
摘要： To test the non-inferiority of Bipolar (B.TUVP) compared to Greenlight laser (GL.PVP) vaporization of the prostate in reduction of BPH-related LUTS in randomized trial. Methods: Eligible patients with 30-80ml prostate were randomly allocated to GL.PVP/XPS? (58) and B.TUVP (61). Non-inferiority of symptoms score (IPSS) at 24 months was evaluated. All perioperative parameters were recorded and compared. Urinary (IPSS, Q.max and PVR) and sexual (IIEF-15) outcome measures were evaluated at 1, 4, 12 and 24 months. Need for retreatment and complications, change of PSA and health-resources related cost of both procedures were depicted and compared. Results: Baseline and perioperative parameters were comparable between the two groups. At 1, 4, 12 and 24 months; 117, 116, 99 and 96 patients were evaluable respectively. Regarding urinary outcome measures, there was no significant difference between both groups. Mean IPSS at one and two years was (7.1±3, 7.9±2.9) following GL.PVP and (6.3±3.1, 7.2±2.8) following B.TUVP (P=0.8, 0.31) respectively. At 24 months the mean difference in the IPSS was 0.7 (95%CI ?0.6-2.3, P=0.6). Median postoperative PSA reduction was 64.7% (25-99) and 65.9% (50-99) following GL.PVP and was 32.1% (28.6-89.7) and 39.3% (68.8- 90.5) following B.TUVP P= 0.006 and 0.005 at 1 and 2 years respectively. After 2 years, retreatment for recurrent BOO was reported in 8 (13.8%) and 10 (16.4%) following GL.PVP and B.TUVP groups respectively (P=0.8). The mean estimated cost per B.TUVP procedure was significantly lower than per GL.PVP procedure after 24 months (P=0.01) Conclusions: In terms of symptoms control, B.TUVP was not inferior to GL.PVP at 2 years. Durability of the outcome needs to be tracked. The cost issue of GL.PVP is a critical concern compared to B.TUVP.
关键词： BPH,prostatectomy,Greenlight,Laser,Bipolar,Prostate,vaporization
更新于2025-09-19 17:13:59
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Is Greenlight laser photoselective vaporization of the prostate a safe technique? Results from a wide monocentric series complications analysis, with a focus on postoperative fever and sepsis
摘要： GreenLight laser Photoselective Vaporization of the Prostate (PVP) is an effective surgical treatment for Benign Prostatic Hyperplasia (BPH). Moreover, its high coagulative power makes GreenLight reliable in high-risk patients (pts). Despite this, post-operative complications still represent a source of concern when surgery is performed in the most fragile pts. The aim of our study was to retrospectively review a large cohort of pts underwent GreenLight PVP and perform a complications analysis, with a focus on post-operative fever and sepsis.
关键词： sepsis,Benign Prostatic Hyperplasia,postoperative complications,Photoselective Vaporization of the Prostate,GreenLight laser,fever
更新于2025-09-19 17:13:59
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Plasmonic Bubble Nucleation in Binary Liquids
摘要： Metal nanoparticles under laser irradiation can produce enormous heat due to surface plasmon resonance. When submerged in a liquid this can lead to the nucleation of plasmonic bubbles. In the very early stage, the nucleation of a giant vapor bubble was observed with an ultrahigh-speed camera. In this study, the formation of this giant bubble on gold nanoparticles (GNPs) in six binary liquid combinations has been investigated. We find that the time delay between the beginning of the laser heating and the bubble nucleation is determined by the absolute amount of dissolved gas in the liquid. Moreover, the bubble volume mainly depends on the vaporization energy of the liquid, consisting of the latent heat of vaporization and the energy needed to reach the boiling temperature. Our results contribute to controlling the initial giant bubble nucleation and have strong bearings on applications of such bubbles.
关键词： binary liquids,Plasmonic bubbles,dissolved gas,vaporization energy,nucleation,gold nanoparticles
更新于2025-09-16 10:30:52
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Dynamics of nanosecond-laser-induced melting of tin in vacuum, air, and water
摘要： Tin with its low melting point and vapor pressure is a good model material to investigate laser ablation mechanisms under various ambient conditions. Here we measured the nanosecond-laser-induced damage thresholds of tin in vacuum, air, and water. The threshold fluence is found to be ~ 0.1 J/cm2 regardless of the environment unlike more refractory metals when threshold values in water are considerably higher than those in air. Analysis of the morphology and chemical composition of the irradiated surface as well as numerical simulations of tin laser heating demonstrate that the observed surface modification is due to melting but not oxidation. For the case of water environment, the conductive heat transfer to water is found to play only a minor role in tin heating and melting. The simulations show also that the formation of a water vapor layer near the tin surface occurs at a considerably higher fluence, above 0.15 J/cm2, and thus the surface damage is not affected by scattering of the incident laser light by the vapor–liquid interface, typical for more refractory metals. Peculiarities of laser ablation of low-melt materials in liquids and nanoparticle formation are discussed.
关键词： Nanosecond laser,Laser ablation,Water vaporization,Nanoparticle formation,Melting,Tin
更新于2025-09-16 10:30:52