Search results for "ablation"
showing 10 items of 322 documents
TRATTAMENTO TERMOABLATIVO DEI NODULI BENIGNI TIRODEI: RFA vs LA
2018
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In-situ high spatial resolution LA-MC-ICPMS 230Th/U dating enables detection of small-scale age inversions in speleothems
2017
Abstract We present an in-situ method for Th and U isotope measurements by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICPMS) to determine possible age inversions of stalagmites, using a 213 nm Nd:YAG laser connected to an MC-ICPMS. Due to the low ion beam intensity of 230 Th (20–120 counts per second, cps), we carefully optimized the operating parameters to get highest possible ion beam intensities, i.e., laser fluence (25 J cm −2 ), spot size (110 μm), pulse repetition rate (20 Hz), scan speed (4 μm s −1 ), integration time (1000 s), and He and Ar gas flow (∼0.9 L min −1 and ∼0.6 L min −1 respectively). A precision (2 relative standard error, 2RSE) o…
X-ray microtomography and laser ablation in the analysis of ink distribution in coated paper
2015
A novel method was developed for studying the ink-paper interface and the structural variations of a deposited layer of ink. Combining high-resolution x-ray tomography with laser ablation, the depth profile of ink (toner), i.e., its varying thickness, could be determined in a paper substrate. X-ray tomography was used to produce the 3D structure of paper with about 1 μm spatial resolution. Laser ablation combined with optical imaging was used to produce the 3D structure of the printed layer of ink on top of that paper with about 70 nm depth resolution. Ablation depth was calibrated with an optical profilometer. It can be concluded that a toner layer on a light-weight-coated paper substrate …
Thyroid surgery and radioiodine ablation—the surgeon's role
2012
Total thyroidectomy and subsequent radioiodine ablation improve the outcome of patients with thyroid tumours measuring >1 cm. Best practice guidelines should serve as a basis for clinical decision making in stage I thyroid cancer; however, Haymart et al. report that soft factors, unrelated to clinical presentation, affect the rate of radioiodine ablation.
[Non-invasive trans-cranial magnetic resonance imaging-guided focused ultrasounds surgery to treat neurologic disorders]
2016
Negli anni passati le applicazioni non invasive degli ultrasuoni focalizzati guidati da risonanza magnetica per il trattamento dei disordini neurologici sono state osta- colate da limiti tecnici oggi finalmente superati. In Italia, nel corso del 2015, sono stati effettuati i primi trattamenti utilizzando per la prima volta al mondo un comune scanner di risonanza magnetica da 1.5T. I risultati a oggi ottenuti con questa nuova metodica e le sue future possibili appli- cazioni sono molto promettenti e aprono la strada verso nuove opzioni terapeutiche, sicure ed efficaci, un tempo impensabili. In past years non-invasive clinical applications of magnetic resonance-guided focused ultrasound for t…
Waiting-time and quality of care deserved to patients with early stage hepatocellular carcinoma undergoing RFA treatment
2017
Element variability in the coralline alga Lithophyllum yemenense as archive of past climate in the Gulf of Aden (NW Indian Ocean)
2017
This study presents the first algal thallus (skeleton) archive of Asian monsoon strength and Red Sea influence in the Gulf of Aden. Mg/Ca, Li/Ca, and Ba/Ca were measured in Lithophyllum yemenense from Balhaf (Gulf of Aden) using laser ablation inductively coupled plasma mass spectrometry, and Mg/Ca ratio oscillation was used to reconstruct the chronology (34 y). Oscillations of element rates corresponding to the algal growth between 1974 and 2008 were compared with recorded climate and oceanographic variability. During this period, sea surface temperatures (SST) in Balhaf recorded a warming trend of 0.55 degrees C, corresponding to an increase in Mg and Li content in the algal thallus of 2.…
Synthesis of Yb nanoparticles by laser ablation of ytterbium target in sodium bis(2-ethylhexyl)sulfosuccinate reverse micellar solution
2010
Abstract Surfactant-coated ytterbium nanoparticles were produced by Nd:YAG laser ablation of a Yb bulk target immersed in sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/ n -heptane micellar solution. In our experimental conditions, as highlighted by IR spectroscopy, AOT molecules are not decomposed by the intense laser pulses but play a pivotal role in the stabilisation of Yb nanoparticles. The formation of Yb nanoparticles in the liquid phase was monitored by UV–Vis spectroscopy whereas the Yb/AOT composites obtained by evaporation of the organic solvent were characterised by XPS and TEM. Data analysis consistently shows the presence of surfactant-coated, nearly spherical and non-interacting…
Short term adaptive response of symbiotic N2 fixation in pea to root pruning of half the root system, linked to the availability of carbon assimilates
2014
Symbiotic N fixation of legumes is very sensitive to environmental stresses, like pea pests damaging nodulated roots. However, the impact on their N uptake capacity and plant growth has not been studied so far.We analyzed the adaptive response symbiotic N2 fixation and plant growth of pea wild type Frisson and hypernodulating mutants P64, P118 and P121 mutated respectively on genes SYM28, SYM29 and NOD3 to root pruning of half the root system at the end of the vegetative stage. The adaptive responses of pea: cv. Frisson and 3 of its hypernodulating mutants were compared under varying carbon supplies from photosynthesis.At 380 ppm, mutant P118 showed the lowest decrease of the specific activ…
Deviation from threshold model in ultrafast laser ablation of graphene at sub-micron scale
2015
International audience; We investigate a method to measure ultrafast laser ablation threshold with respect to spot size. We use structured complex beams to generate a pattern of craters in CVD graphene with a single laser pulse. A direct comparison between beam profile and SEM characterization allows us to determine the dependence of ablation probability on spot-size, for crater diameters ranging between 700 nm and 2.5 μm. We report a drastic decrease of ablation probability when the crater diameter is below 1 μm which we interpret in terms of free-carrier diffusion.