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Purpose In the USA, 22–40% of youth who have been accepted to college do not enroll. Researchers call this phenomenon summer melt, which disproportionately affects students from disadvantaged backgrounds. A major challenge is providing enough mentorship with the limited number of available college counselors. The purpose of this study is to present a case study of a design and user study of a chatbot (Lilo), designed to provide college advising interactions. Design/methodology/approach This study adopted four primary data sources to capture aspects of user experience: daily diary entries; in-depth, semi-structured interviews; user logs of interactions with the chatbot; and daily user surveys. User study was conducted with nine participants who represent a range of college experiences. Findings Participants illuminated the types of interactions designs that would be particularly impactful for chatbots for college advising including setting reminders, brokering social connections and prompting deeper introspection that build efficacy and identity toward college-going. Originality/value As a growing body of human-computer interaction research delves into the design of chatbots for different social interactions, this study illuminates key design needs for continued work in this domain. The study explores the implications for a specific domain to improve college enrollment: providing college advising to youth.

Inefficient imaging practices merit renewed attention in preparation for full implementation of the Appropriate Use Criteria Program. This study's purpose is to quantify changes in outpatient brain CT imaging efficiency from 2013 to 2018, including changes in relative efficiency by hospital category.Imaging efficiency data were obtained from the Medicare Hospital Compare website. Summary statistics were calculated for rates of unnecessarily combined brain and sinus CT scans from 2013 to 2018. Relative performance was compared by hospital Medicare payment structure, type of ownership, and affiliation with a radiology residency program. The predictive value of these hospital characteristics on brain CT efficiency was determined using linear regression analysis.From 2013 to 2018, the mean frequency of unnecessarily combined brain and sinus CT scans decreased by 1.82% (95% confidence interval, 1.74%-1.90%). Proprietary and physician-owned hospitals exhibited a higher mean frequency of combined scans than other hospitals in 2013 (P.001), and government-owned hospitals exhibited a lower mean frequency of combined scans than other hospitals in 2018 (P.001). Radiology residency-affiliated hospitals exhibited no significant difference in 2013 but exhibited a higher mean frequency in 2018 (difference: 0.45%; 95% confidence interval, 0.29%-0.61%). Critical access hospital status and nonaffiliation with a radiology residency program were the strongest predictors of brain CT efficiency in the regression model.Recent changes in hospitals' relative brain CT efficiency suggest category-specific differences in responsiveness to quality improvement efforts and may foreshadow similar trends under forthcoming initiatives.

Solid-phase peptide synthesis (SPPS) is the method of choice for the preparation of peptides in both laboratory scale and large production. Although the methodology has been improved during the last decades allowing the achievement of long peptides and challenging sequences in good yields and purities, the process was not revised from an environmental point of view. One of the main problems in this regard is the large amount of solvents used, and therefore the tons of generated waste. Moreover, the solvent of choice for the SPPS is N,N-dimethylformamide (DMF), which is considered as reprotoxic; thus, there is an urgent necessity to replace it with safer solvents. The DMF substitution by a green solvent is not a trivial task, because it should solubilize all the reagents and byproducts involved in the process, and, in addition to facilitating the coupling of the different amino acids, it should not favor the formation of side-reactions compared with DMF. Herein, it was demonstrated that the use of the green solvent N-butylpyrrolidinone (NBP) as a replacement of DMF was beneficial in two well-documented side reactions in peptide synthesis, racemization and aspartimide formation. The use of NBP rendered a lower or equal level of racemization in the amino acids more prone to this side reaction than DMF, whilst the aspartimide formation was clearly lower when NBP was used as solvent. Our findings demonstrate that the use of a green solvent does not hamper the synthetic process and could even improve it, making it environmentally friendlier and synthetically better., The work was funded in part by the following: the National Research Foundation (NRF) (# 105892 and Blue Sky's Research Programme # 120386) and the University of KwaZulu‐Natal (South Africa); and the Spanish Ministry of Science, Innovation, and Universities (RTI2018‐093831‐B‐100) and the Generalitat de Catalunya (2017 SGR 1439) (Spain).

Rehabilitation strategies after traumatic spinal cord injury aim to maximize functional recovery by applying principles of neuroplasticity via task-specific, repetitive training. Rehabilitation of patients with traumatic spinal cord injury poses unique challenges, including bilateral limb involvement, autonomic dysfunction, loss of proprioception, and potentially spinal precautions/bracing. The purpose of this retrospective case series was to determine whether use of dynamic body weight support would yield greater improvement in functional recovery compared with standard of care in adults with traumatic spinal cord injury. Data were collected from patients with traumatic spinal cord injury who completed inpatient rehabilitation incorporating dynamic body weight support (n = 5) and who completed inpatient rehabilitation without dynamic body weight support (n = 5). The primary outcome measure was the change in Functional Independence Measures. The dynamic body weight support group had a significantly greater improvement in Total Functional Independence Measures and in Functional Independence Measures motor subscale compared with the standard of care group (P = 0.023 and P = 0.033, respectively). This study presents initial evidence that dynamic body weight support therapy during inpatient rehabilitation has the potential to improve functional independence compared with standard of care in patients with traumatic spinal cord injury. Larger prospective randomized studies need to be conducted to expand on these findings.

We report on high aspect ratio and high-speed glass drilling with femtosecond GHz-bursts. The drilling process dynamics of deep and high-quality holes in different glasses and sapphire is monitored by in-situ microscopy and thermal imaging.

Peptides are the basis of many drugs currently on the market and of more in advanced studies. Most peptides are synthesized using solid-phase peptide synthesis (SPPS). A characteristic of this strategy is that synthetic intermediates are not isolated. In this context, the development of a real-time monitoring method would assure an optimal synthetic process. The refractive index (RI) of a liquid provides key information about its physical properties and the composition of any solution. Here, we provide the first demonstration that the RI is a process analytical tool (PAT) suitable for the real-time monitoring of SPPS. This strategy comprises three steps: coupling, deprotection, and washes, which can be monitored online by refractometry. Given that monitoring capacity helps in the determination of the endpoint of the reactions and the optimization of all synthetic steps, it has a direct impact on the consumption of reagents, solvents, and time, thereby contributing to greener SPPS., The work was financially supported in part by the National Research Foundation (NRF) (Blue Sky Research Programme Nos.105892 and 110960) and the University of KwaZulu-Natal (South Africa).

In the present work, we investigate the benefits and the drawbacks in using on dual-wavelength double fs-pulse laser irradiation for fused silica processing. Our purpose of this pump-pump experiment is to tune the electron dynamics in order to optimize energy deposition and then to improve ablated volume. We use green wavelength (515 nm) for the first pulse to enhance photo-ionization and near-infrared (1030 nm) for the second pulse to maximize electron heating and impact ionization. The investigated parameters are pulse-to-pulse delay (up to 20 ps), second pulse duration (1 and 10 ps) and total fluence (up to 20 J/cm²). The results will be discussed in terms of ablated volume and optical transmission. We demonstrate that (i) there is an optimum delay and (ii) the ablation behavior is intermediate between green and near-infrared single pulse irradiation. Our results are supported by a numerical model taking into account electron dynamics and absorbed energy density.

The protection of side-chain arginine in solid-phase peptide synthesis requires attention since current protecting groups have several drawbacks. Herein, the NO2 group, which is scarcely used, has been revisited. This work shows that it prevents the formation of δ-lactam, the most severe side-reaction during the incorporation of Arg. Moreover, it is stable in solution for long periods and can be removed in an easy-to-understand manner. Thus, this protecting group can be removed while the protected peptide is still anchored to the resin, with SnCl2 as reducing agent in mild acid conditions using 2-MeTHF as solvent at 55 °C. Furthermore, we demonstrate that sonochemistry can facilitate the removal of NO2 from multiple Arg-containing peptides.

The modern electrophysiology (EP) Laboratory caters to two general categories of diagnostic and interventional procedures. They can be classified as either ablation or device related. Ablation procedures are more involved and may require more equipment and time than device-related procedures. The EP Lab should be constructed following the Facility Guidelines Institute. The typical EP laboratory design may use the Cath Lab design settings but there needs to be a separate distinction due to the fact that the EP Laboratory houses more equipment and is sensitive to a different need that concentrates in the matter of interpreting clean electrical signals as opposed to pressures and hemodynamics. As technology advances, procedural considerations and need dynamically evolve and should be expected. The equipment needed for cardiac implantable electrical devices implantation include X-Ray System; EP Recording System, Device Specific Programmer & Signal Analyzer; and Emergency Equipment (Defibrillator, Temporary Pacemakers, Open Chest, and Emergency Carts).

Ultrafast laser glass processing is highly interesting for microelectronics and consumer electronics industries. Indeed, ultrafast laser technology has the unique capacity to produce a high-quality surface or bulk modification in dielectric transparent materials thank to nonlinear absorption. However, there is a need to improve both processing quality and throughput in order to meet the industry requirements. Beam shaping, performed by tuning spatial or temporal intensity profile, polarization, fluence, or any other laser parameters, is a smart and flexible technique to achieve this goal. This work is dealing with double fs-pulse laser irradiation of fused silica. Our purpose is to investigate the benefits and the drawbacks in using single and dual-wavelength double fs-pulse laser irradiation of fused silica. The influence of pulse-to-pulse delay (0 to 5 ps), pulse duration of the second pulse (1 ps to 25 ns) and fluence on both removal rate and optical transmission will be discussed.

Debugging is an important skill for novice programmers to master, but many students struggle to learn how to debug due in part to difficulty with program syntax. Block-based environments provide an alternative to traditional textual programming that reduces syntax errors, and recently hybrid block-based/textual environments have become more common. This poster presents preliminary research to understand how novice debugging strategies differ between block- based and hybrid environments. We assigned seven participants to debug four programs within one of the two environments and conducted interviews about their debugging approaches. Thematic analysis of interview responses suggest that students adjusted their strategies based on their prior experience with textual environments. By understanding novice programmers' strategies in these environments, the field can move toward more effectively support- ing productive strategies.

NBP has proved an excellent alternative solvent to the hazardous DMF for SPPS. Here we studied the incorporation of Fmoc-Arg(Pbf)-OH, one of the most problematic amino acids, into a growing peptide chain. The poor performance of this amino acid is attributed to the formation of a fully inactive δ-lactam, which causes a reduction in yield and very often the concomitant formation of the corresponding des-Arg peptides. This problem is exacerbated when NBP is used as solvent, presumably because of its high viscosity, which impairs the penetration of the coupling cocktail into the resin. To tackle this issue, we propose the following strategy for the safe introduction of Fmoc-Arg(Pbf)-OH in SPPS at 45 °C, keeping excesses to a minimum: 1.75 equiv. of the protected amino acids, 1.8 equiv. of DIC, and 1.5 equiv. of OxymaPure. The cornerstone of the strategy is to carry out in situ activation. In this regard, Fmoc-Arg(Pbf)-OH and OxymaPure dissolved in NBP were added to peptidyl-resin, allowed to reach the 45 °C, then half the DIC was added and left for 30 min, followed by the other half and some extra Fmoc-Arg(Pbf)-OH. During the entire process, the temperature was kept at 45 °C, with the double purpose of reducing the viscosity of NBP, thus facilitating the penetration of the coupling cocktail into the resin, and speeding up the coupling itself. It is envisaged that this strategy could be widely used to improve the performance of SPPS, including the industrial preparation of peptides using this approach., The work was funded in part by the following: the National Research Foundation (NRF) (# 105892 and Blue Sky’s Research Programme # 110960) and the University of KwaZulu-Natal (South Africa); and the Spanish Ministry of Science, Innovation, and Universities (CTQ2015-67870-P) and the Generalitat de Catalunya (2017 SGR 1439) (Spain).

By means of a systematic approach, several green solvent candidates were tested for their feasibility to replace the reprotoxic dimethylformamide (DMF) as a solvent used in solid-phase peptide synthesis (SPPS). According to the results presented in this paper, it is clear that N-butylpyrrolidinone (NBP) is the best green solvent candidate to replace DMF in SPPS.

Background The extent of coronary disease affects clinical outcomes and may predict the effectiveness of coronary revascularization with either coronary artery bypass graft (CABG) surgery or percutaneous coronary intervention (PCI). The SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score quantifies the extent of coronary disease. Objectives This study sought to determine whether SYNTAX scores predicted outcomes and the effectiveness of coronary revascularization compared with medical therapy in the BARI-2D (Bypass Angioplasty Revascularization Investigation 2 Diabetes) trial. Methods Baseline SYNTAX scores were retrospectively calculated for BARI-2D patients without prior revascularization (N = 1,550) by angiographic laboratory investigators masked to patient characteristics and outcomes. The primary outcome was major cardiovascular events (a composite of death, myocardial infarction, and stroke) over 5 years. Results A mid/high SYNTAX score (≥23) was associated with a higher risk of major cardiovascular events (hazard ratio: 1.36, confidence interval: 1.07 to 1.75, p = 0.01). Patients in the CABG stratum had significantly higher SYNTAX scores: 36% had mid/high SYNTAX scores compared with 13% in the PCI stratum (p Conclusions Among patients with diabetes and stable ischemic heart disease, higher SYNTAX scores predict higher rates of major cardiovascular events and were associated with more favorable outcomes of revascularization compared with medical therapy among patients suitable for CABG. (Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes; NCT00006305)

We sought to compare outcomes with radial vs femoral approach in female patients undergoing coronary angiography.Women undergoing cardiac procedures have increased risk of bleeding and vascular complications, but are under-represented in randomized clinical trials (RCTs) involving coronary angiography.We performed a meta-analysis of RCTs comparing outcomes in women undergoing angiography with radial vs femoral approaches. The primary outcome was non-coronary artery bypass graft (CABG) related bleeding at 30 days. Secondary outcomes included major adverse cardiovascular or cerebrovascular events (MACCE; a composite of death, stroke or myocardial infarction), vascular complications, procedure duration, and access-site crossover.Four studies (n = 6041 female patients) met the inclusion criteria. In female patients undergoing coronary angiography, radial access decreased non-CABG related bleeding (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.44-0.72; P.001), MACCE (OR, 0.73; 95% CI, 0.58-0.93; P=.01), vascular complications (OR, 0.49; 95% CI, 0.32-0.75; P.001) with no significant difference in procedure time (mean difference, 0.04; 95% CI, -0.97 to 0.89; P=.93). There was an increase in access-site crossover using the radial approach (OR, 2.86; 95% CI, 2.24-3.63; P.001). Patients undergoing radial approach were more likely to prefer radial access for the next procedure (OR, 6.96; 95% CI, 5.70-8.50; P.001).In female patients undergoing coronary angiography or intervention, the radial approach is associated with decreased bleeding, MACCE, and vascular complications. These data suggest that radial access should be the preferred approach for women.

We present a high-power femtosecond GHz burst laser with nonlinear frequency conversion to the ultraviolet spectral region. An average power as high as 20-W at 343nm wavelength has been obtained after third harmonic generation of a 100-W, 480-fs GHz burst mode femtosecond laser at 1030nm. This is to our knowledge the first demonstration of a high-power ultraviolet femtosecond laser with GHz bursts. GHz femtosecond lasers have recently revealed significant interest for micro-machining applications, in particular by showing substantially increased ablation efficiencies on different materials [1, 2]. Frequency conversion to the ultraviolet spectral region is highly interesting for spatial and chemical selectivity in multi-material or multi-layer material processing, especially for materials containing organic components. Our high-power UV femtosecond GHz burst laser is therefore promising for high efficiency and high-quality laser processing of polymer-based materials with low heat affected zones.

We report on silicon ablation with a 20 W GHz amplified femtosecond laser source. This novel laser delivers burst energies up to 400 μJ, providing flexible intra-pulse repetition rates of 0.88 or 3.52 GHz, up to 200 pulses with ∼350 fs pulse duration. High-efficiency, high-quality ablation can be achieved through optimally determining the number of pulses, intra-pulse repetition, and average pulse energy within a burst. Due to such optimization, we demonstrate a specific ablation rate of 2.5 mm3/min/W with a burst containing 200 pulses at 0.88 GHz, which is the highest one reported so far for fs laser ablation, to the best of our knowledge. GHz ablation is sensitive to the selection of laser parameters. We conceptually discuss the contributions of the pulses within a burst to heat-accumulation-based incubation and material ablation.

Laser surface texturing is an established way to introduce surface functionalities on solid surfaces. By means of femtosecond laser sources, it’s possible to texture a variety of solids such as metals, semiconductors and transparent materials, introducing features of different symmetry and size. Fabrication of laser induced periodic surface structure (LIPSS) which typically range in the near-submicron length scale can lead to strong modifications of surface wetting, tribological and optical properties. Controlling LIPSS morphology could enable us to mimic functional textures found in nature, introducing functionalities such as antireflectivity and bactericidity. Several works demonstrate the impact of polarization control and double-pulse irradiation on determining texture symmetry and size. Here we present a comprehensive study on controlling laser induced structures by double femtosecond pulse irradiation. The effect of pulse polarization and interpulse delay is elucidated and the generation of novel 2D surface morphologies is reported. A plausible interpretation of the structure formation mechanism is proposed in the frame of non-linear convection flow. A high average power industrial femtosecond laser source with a pulse duration of 350 fs operating at high repetition rate was employed for the experiments. Large areas were processed by combining different 2D morphologies generating a holographic pattern. We believe that our results provide a novel insight in controlling laser induced submicron morphology. Moreover, the presented surface texturing process is scalable in terms of processed area and cycle time and fully compatible with high repetition rates, demonstrating for the first time the feasibility to introduce double-pulse processing in an industrial environment.

Introduction: Pulmonary embolism (PE) is associated with significant acute morbidity, mortality, and long term functional limitations. There is paucity of data on acute and short term functional assessment after acute PE. Hypothesis: Functional capacity will improve from baseline to follow up among patients with acute PE. Methods: We prospectively analyzed patients who underwent evaluation by the pulmonary embolism response team (PERT) at Loyola University Medical Center between 2016 and 2018. We included patients with acute PE who underwent six-minute walk test (6MWT) at discharge and during outpatient follow up (50±72 days post discharge). We collected demographic and clinical characteristics. We used paired sampled t-test to compare continuous variables. Results: Among the 204 patients evaluated by PERT, 38 patients (18.6%) underwent 6MWT at baseline and follow up. Patients were classified as low risk (6 patients), submassive (29 patients), and massive (3 patients). Mean age was 61.3±14.2, 50% were female, 60.5% were white, 26.3% were black, 29% had cancer, and 68.4% had concomitant DVT, mean BMI 36.4±10.3, and mean PESI score was 96.8+44.4. Overall the mean 6MWT distance increased significantly from a baseline of 726.9±73.7 feet to 1042±72.8 feet at follow up (p Conclusions: Functional capacity as measured by 6MWT significantly improved during follow up after acute PE. Future studies are needed to determine predictors of favorable functional outcome and best treatment strategies.

We report on crater formation, line scribing and cavity milling experiments on Silicon, Copper, Aluminum and stainless steel with GHz bursts of femtosecond pulses. The intra-burst repetition rate has been varied between 0.88 and 3.52 GHz, the number of pulses per burst between 50 and 3200, the burst fluence between 8 and 80 J/cm2. For these experiments, a 100-W femtosecond GHz-burst laser has been developed on an industrial laser basis, delivering a total burst energy up to 1 mJ at 100 kHz, with an adjustable number of pulses per burst. The results highlight the conditions to obtain high-ablation efficiency, show how to optimize the machining quality and point out the burst duration as the relevant parameter for femtosecond GHz machining.

The protection of side-chain arginine in solid-phase peptide synthesis requires attention since current protecting groups have several drawbacks. Herein, the NO2 group, which is scarcely used, has been revisited. This work shows that it prevents the formation of δ-lactam, the most severe side-reaction during the incorporation of Arg. Moreover, it is stable in solution for long periods and can be removed in an easy-to-understand manner. Thus, this protecting group can be removed while the protected peptide is still anchored to the resin, with SnCl2 as reducing agent in mild acid conditions using 2-MeTHF as solvent at 55 °C. Furthermore, we demonstrate that sonochemistry can facilitate the removal of NO2 from multiple Arg-containing peptides., The work was funded in part by the following: the National Research Foundation (NRF) (# 105892 and Blue Sky’s Research Programme # 120386) and the University of KwaZulu-Natal (South Africa); the Spanish Ministry of Science, Innovation, and Universities (RTI2018-093831-B-100), and the Generalitat de Catalunya (2017 SGR 1439) (Spain). We thank to Dr. Peter White and Millipore-Sigma-Aldrich for supporting part of this research. We thank Dr. Jonathan A. Collins (CEM) for facilitating the use of the microwave instrument.

Glass processing is a subject of high interest for many industrial fields such as optics manufacturing, smart electronics or medical devices. With respect to nanosecond technology, the use of femtosecond lasers allows to achieve high processing quality thanks to nonlinear absorption properties. Nevertheless, the throughput of femtosecond processing is still very low when compared to other laser technologies. Temporal and spatial pulse shaping is a smart and flexible solution to further increase the efficiency of femtosecond laser processing by driving efficiently both electron dynamics and absorption involved during laser irradiation. In the present work, the effect of temporal pulse shaping on fused silica ablation is investigated by single-wavelength (1030nm) double femtosecond pulses pump-pump experiment. Two sub-pulses are focused on the top surface of fused silica with two different polarization configurations: (i) orthogonally-crossed linear polarization or (ii) counter-rotating circular polarization. The investigated parameters are the pulse-to-pulse delay, set with a delay line, the total fluence and the polarization configuration. The results are discussed in term of optical transmission, modification and ablation thresholds, and ablated volume. A numerical model describing the electron dynamics and the absorbed energy density is also presented to support interpretation of experimental results. It is demonstrated that pulse-to-pulse delay has a major influence on ablated volume, modification and ablation threshold. Polarization state has also, to a lesser extent, a significant influence on ablated volume. Their cooperative effect on the ablation efficiency is discussed.

Femtosecond lasers have been proved to be an effective fabrication tool to process with high machining quality and negligible thermal effects a wide variety of materials. However, the system technology enabling fast and precise scanning on the workpiece, currently limits the average power of these laser sources to less than 10 Watts of average power in most industrial application. To overcome this limitation, a proportional up-scaling of both, the laser repetition rate and scan speed is needed, demanding for faster scanning technologies. Recently, rugged, femtosecond lasers delivering pulses with repetition rates of several MHz and pulse energy up to some hundreds of μJ have been introduced to the market. In parallel, the development and commercialization of novel galvanometric scanner heads, enabling scan speeds well above 10 m/s is ongoing. Here we explored the capabilities of a novel set-up consisting of an industrial femtosecond laser delivering 100 W with a repetition rate up to 13 MHz coupled with an innovative galvanometric scanner head enabling scan speeds up to 30 m·s-1. On stainless steel, we carried out engraving tests with both single line grooving and multiple surface raster scanning. By systematic variation of repetition rate and pules overlap we investigate how the machining quality and the ablation rate depend on the average laser power at different fluence levels. Heat accumulation effects are evaluated via Scanning Electron Microscope. Finally, we show how to scale-up the cutting of a 500 μm thick stainless-steel part varying the scan speed from 1 m·s-1 to 20 m·s-1.

We present a systematic study on the generation of 2D surface structures on stainless steel, using double, crosspolarized femtosecond pulses with variable interpulse delay. We demonstrate the combined effect of the interpulse delay and key process parameters in order to obtain periodic structures. The sets of double pulses were produced utilizing a modified Michelson interferometer with interpulse delay varying from -100 ps to +2 ns. The study was carried out with an industrial laser having pulse duration of 350 fs, emitting in the near infrared (λ = 1030 nm), operating at 100 kHz coupled with a Galvo scanner. We evaluate the obtained surface morphology and structure period using SEM characterization and Fourier analysis.

Nowadays the relevance and the robustness of ultrafast lasers are well established for many industrial applications. Indeed this laser technology combines the unique capacity to process any type of material with an outstanding processing precision and a minimal heat affected zone. The key issue is to combine high throughput, low residual thermal load and good processing quality. Thanks to high average power and high repetition rate it is possible to achieve high throughput providing that the operating parameters are precisely tuned to the application, otherwise heat accumulation and heat affected zone may appear, leading to detrimental effects such as burr, uncontrolled melting and metal oxidation. In this paper we report on high-throughput laser ablation of metals using a 100W- and 10MHz- ultrafast laser. Target materials were stainless steel, Copper, and Aluminum. Operating parameters such as fluence, repetition rate and scanning velocity have been considered. Results are discussed in terms of ablation efficiency, surface morphology, multipass and upscaling capabilities. Different behaviors between materials are also discussed. We observe that pulse-to-pulse pitch and delay are key parameters that must be taken into account in order to define relevant process windows for each material. The use of polygon scanner instead of galvo scanner enables us to reduce the thermal load along the laser trajectory. The point is not to avoid heat accumulation but to take advantage of this phenomenon as long as the target material can stand the thermal load without detrimental effects on the processing quality.

International audience; The formation and the interaction of multiple cavities, induced by tightly focused femtosecond laser pulses, are studied using a developed numerical tool, including the thermo-elasto-plastic material response. Simulations are performed in fused silica in cases of one, two, and four spots of laser energy deposition. The relaxation of the heated matter, launching shock waves in the surrounding cold material, leads to cavity formation and emergence of areas where cracks may be induced. Results show that the laser-induced structure shape depends on the energy deposition configuration and demonstrate the potential of the used numerical tool to obtain the desired designed structure or technological process.

Surface Texturing by USP laser