Search

Revived interest in proton-boron fusion has been fuelled by new laser matter interaction schemes with several possible applications. The authors report on a tabletop laser experiment that observes proton-boron fusion with an emphasis on the secondary cross-section peak around 150 keV.

An experimental platform for laser-driven ion (sub-MeV) acceleration and potential applications was commissioned at the HiLASE laser facility. The auxiliary beam of the Bivoj laser system operating at a GW level peak power (~10 J in 5–10 ns) and 1–10 Hz repetition rate enabled a stable production of high-current ion beams of multiple species (Al, Ti, Fe, Si, Cu, and Sn). The produced laser–plasma ion sources were fully characterized against the laser intensity on the target (1013–1015 W/cm2) by varying the laser energy, focal spot size, and pulse duration. The versatility and tuneability of such high-repetition-rate laser–plasma ion sources are of potential interest for user applications. Such a statistically accurate study was facilitated by the large amount of data acquired at the high repetition rate (1–10 Hz) provided by the Bivoj laser system.

The placement of a feeding jejunostomy can be indicated in malnourished patients with gastric and oesophagogastric junction cancer to allow for enteral nutritional support. In these patients, the jejunostomy tube can be suitably placed at the time of staging laparoscopy. Several techniques of laparoscopic jejunostomy (LJ) have been described, yet the Witzel approach remains neglected, due to the perceived difficulty of suturing the bowel around the tube and securing them to the abdominal wall. Here, we describe a novel technique for LJ, using a single barbed suture for securing the bowel and tunnelling the jejunostomy catheter according to the Witzel approach.

Abstract Background Acute calculus cholecystitis (ACC) has a high incidence in the general population. The presence of several areas of uncertainty, along with the availability of new evidence, prompted the current update of the 2016 WSES (World Society of Emergency Surgery) Guidelines on ACC. Materials and methods The WSES president appointed four members as a scientific secretariat, four members as an organization committee and four members as a scientific committee, choosing them from the expert affiliates of WSES. Relevant key questions were constructed, and the task force produced drafts of each section based on the best scientific evidence from PubMed and EMBASE Library; recommendations were developed in order to answer these key questions. The quality of evidence and strength of recommendations were reviewed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria (see https://www.gradeworkinggroup.org/ ). All the statements were presented, discussed and voted upon during the Consensus Conference at the 6th World Congress of the World Society of Emergency Surgery held in Nijmegen (NL) in May 2019. A revised version of the statements was voted upon via an online questionnaire until consensus was reached. Results The pivotal role of surgery is confirmed, including in high-risk patients. When compared with the WSES 2016 guidelines, the role of gallbladder drainage is reduced, despite the considerable technical improvements available. Early laparoscopic cholecystectomy (ELC) should be the standard of care whenever possible, even in subgroups of patients who are considered fragile, such as the elderly; those with cardiac disease, renal disease and cirrhosis; or those who are generally at high risk for surgery. Subtotal cholecystectomy is safe and represents a valuable option in cases of difficult gallbladder removal. Conclusions, knowledge gaps and research recommendations ELC has a central role in the management of patients with ACC. The value of surgical treatment for high-risk patients should lead to a distinction between high-risk patients and patients who are not suitable for surgery. Further evidence on the role of clinical judgement and the use of clinical scores as adjunctive tools to guide treatment of high-risk patients and patients who are not suitable for surgery is required. The development of local policies for safe laparoscopic cholecystectomy is recommended.

Abstract Background Treatment of esophageal perforations and postoperative anastomotic leaks of the upper gastrointestinal tract remains a challenge. Endoluminal vacuum-assisted closure (E-Vac) therapy has positively contributed, in recent years, to the management of upper gastrointestinal tract perforations by using the same principle of vacuum-assisted closure therapy of external wounds. The aim is to provide continuous wound drainage and to promote tissue granulation, decreasing the needed time to heal with a high rate of leakage closure. Cases presentation A series of two different cases with clinical and radiological diagnosis of esophageal fistulas, recorded from 2018 to 2019 period at our institution, is presented. The first one is a case of anastomotic leak after esophagectomy for cancer complicated by pleuro-mediastinal abscess, while the second one is a leak of an esophageal suture, few days after resection of a bronchogenic cyst perforated into the esophageal lumen. Both cases were successfully treated with E-Vac therapy. Conclusion Our experience shows the usefulness of E-Vac therapy in the management of anastomotic and non-anastomotic esophageal fistulas. Further research is needed to better define its indications, to compare it to traditional treatments and to evaluate its long-term efficacy.

A 1:50,000 hydrogeological map of the Pale di San Martino Mountains (Northern Italy) was created. The map presents the merge of various pre-existing data with new field data collected between the years 2014 and 2016. Through the use of symbols and specific colours, the map shows various groundwater-related data such as the hydrogeological complexes, the location and size of the main springs, the extension of the recharge areas, the hydrogeological boundaries, as well as information on groundwater usage. Given the absence of hydrogeological maps in the entire mountain range of the Dolomites, the approach followed in this study could be used as a guide for future representations in this alpine region. At the local scale, the map could serve as a conceptual base for future research involving groundwater and for water management planning.

O minimilho é o nome dado às inflorescências femininas da planta de milho, colhidas antes da fertilização, sendo seu cultivo uma alternativa rentável para pequenas propriedades. Objetivou-se avaliar diferentes espaçamentos (0,5; 0,6; 0,7; 0,8 e 0,9 m) entrelinhas e densidades de semeadura (13, 15 e 17 plantas por metro) de minimilho. O estudo foi conduzido na Universidade Estadual do Norte do Paraná, Campus Luiz Meneghel, com delineamento experimental em blocos ao acaso em esquema fatorial 5 x 3 (espaçamento; densidade) com quatro repetições. As parcelas experimentais compreendiam cinco metros de comprimento por seis metros e meio de largura, o cultivar escolhido de milho híbrido foi o AG1051. As características avaliadas da cultura foram diâmetro do caule, comprimento da espiga com e sem palha, diâmetro da espiga com e sem palha, índice de formato da espiga, produtividade com palha, produtividade sem palha e produtividade padrão indústria. O diâmetro do colmo e o tamanho de espigas apresentaram característica quadrática para o espaçamento. As espigas não apresentaram formato perfeitamente cilíndrico. A produtividade do minimilho não foi afetada pelos espaçamentos e densidades.

O projeto ARANDU tem como principal objetivo aproximar os alunos da rede pública, do 9º ano do ensino fundamental e do ensino médio, ao ambiente de engenharia. Para tanto, a metodologia adotada foi confeccionar um curso no qual são ministradas aulas básicas de diversas áreas da engenharia, e que tem como produto final a construção de um pico-satélite denominado “CanSat”. As aulas ocorrem no dueto “teoria x prática”. O aprendizado desenvolvido é fundamental, pois promove o raciocínio lógico, comunicação, trabalho em equipe e criatividade, além do conhecimento básico necessário para a criação do CanSat. Além disto, como objetivo secundário, incentivar ingresso na faculdade/universidade ou no mercado de trabalho. Neste trabalho, serão expostas as atividades do projeto ARANDU 2018. Serão descritas as estruturas adotadas, as aplicações das aulas e os resultados obtidos. E, por fim, a avaliação do projeto na perspectiva do aluno. Os resultados mostram que projetos com esta abordagem, “movimento Maker”, acrescentam benefícios relevantes aos alunos em relação aos conhecimentos acadêmicos.

Extreme precipitation events are expected to increase in intensity in Alpine regions due to climate change. While many studies have analyzed the impact of these phenomena on flooding risk, very few deal with their effect on groundwater. This work analyzes the hydrograph response of three springs to an extreme storm, which occurred in Northern Italy in October 2018. We observed that the newly infiltrated storm water contributed to feeding the winter baseflow, increasing its volume up to 85 % compared to normal conditions. It was also found that the response of groundwater to heavy precipitation seems to be influenced by the type of media. A high-altitude spring belonging to the fractured carbonate aquifer shows a quick response to the storm input, while springs outflowing at the base of the mountain slopes (mixed fractured carbonate and porous deposits) exhibit a delayed response. Results are important when analyzing future water availability and to better understand the impact of extreme events on groundwater flow.

The relatively narrow choice of magneto-active materials that could be used to construct Faraday devices (such as rotators or isolators) for the mid-infrared wavelengths arguably represents a pressing issue that is currently limiting the development of the mid-infrared lasers. Furthermore, the knowledge of the magneto-optical properties of the yet-reported mid-infrared magneto-active materials is usually restricted to a single wavelength only. To address this issue, we have dedicated this work to a comprehensive investigation of the magneto-optical properties of both the emerging (Dy2O3 ceramics and CeF3 crystal) and established (Y3Fe5O12 crystal) mid-infrared magneto-active materials. A broadband radiation source was used in a combination with an advanced polarization-stepping method, enabling an in-depth analysis of the wavelength dependence of the investigated materials’ Faraday rotation. We were able to derive approximate models for the examined dependence, which, as we believe, may be conveniently used for designing the needed mid-infrared Faraday devices for lasers with the emission wavelengths in the 2-μm spectral region. In the case of Y3Fe5O12 crystal, the derived model may be used as a rough approximation of the material’s saturated Faraday rotation even beyond the 2-μm wavelengths.

In this paper, we introduce a method to efficiently use a high-energy pulsed 1.7 ps HiLASE Perla laser system for two beam interference patterning. The newly developed method of large-beam interference patterning permits the production of micro and sub-micron sized features on a treated surface with increased processing throughputs by enlarging the interference area. The limits for beam enlarging are explained and calculated for the used laser source. The formation of a variety of surface micro and nanostructures and their combinations are reported on stainless steel, invar, and tungsten with the maximum fabrication speed of 206 cm2/min. The wettability of selected hierarchical structures combining interference patterns with 2.6 µm periodicity and the nanoscale surface structures on top were analyzed showing superhydrophobic behavior with contact angles of 164°, 156°, and 150° in the case of stainless steel, invar, and tungsten, respectively.

Springs play a key role in the hydrology of mountain catchments and their water supply has a considerable impact on regional livelihood, biodiversity, tourism, and power generation. However, there is still limited knowledge of how rain and snow contribute to the recharge of Alpine springs. This study presents a four-year investigation of stable isotopes in precipitation and spring water at the scale of a 240 km2 wide dolomitic massif (Dolomites, Italian Alps) with the aim of determining the proportions of snowmelt and rain in spring water and to provide insights on the variability of these contributions in space and time. Four precipitation sampling devices were installed along a strong elevation gradient (from 725 to 2660 m a.s.l.) and nine major springs were monitored seasonally. The monitoring period comprised three extreme weather conditions, i.e., an exceptional snowpack melting period following the highest snowfall in 30 years, an intense precipitation event (386.4 mm of rain in 48 h), and one of the driest periods ever observed in the region. Isotope-based mixing analysis revealed that rain and snowmelt contributions to spring water were noticeably variable, with two main recharge time windows: a late spring–summer snowmelt recharge period with an average snowmelt fraction in spring water up to 94 ± 9%, and a late autumn–early winter period with a rain fraction in spring water up to 68 ± 17%. Overall, during the monitoring period, snowmelt produced high-flow conditions and sustained baseflow more than rain. We argue that the seasonal variability of the snowmelt and rain fractions during the monitoring period reflects the relatively rapid and climate-dependent storage processes occurring in the aquifer. Our results also showed that snowmelt fractions in spring water vary in space around the mountain group as a function of the elevation of their recharge areas. High-altitude recharge areas, above 2500 m a.s.l., are characterized by a predominance of the snowmelt fraction (72% ± 29%) over the rain contribution. Recharge altitudes of approximately 2400 m a.s.l. also show a snow predominance (65 ± 31%), while springs recharged below 2000 m a.s.l. are recharged mostly from rain (snowmelt fraction of 46 ± 26%). Results from this study may be used to develop more accurate water management strategies in mountain catchments and to cope with future climate-change predictions that indicate a decline in the snow volume and duration in Alpine regions.

To fulfil the requirements for high-resolution organic light-emitting diode (OLED) displays, precise and high-quality micrometer-scale patterns have to be fabricated inside metal shadow masks. Invar has been selected for this application due to its unique properties, especially a low coefficient of thermal expansion. In this study, a novel cost-efficient method of multi-beam micromachining of invar will be introduced. The combination of a Meopta beam splitting, focusing and monitoring module with a galvanometer scanner and HiLASE high-energy pulse laser system emitting ultrashort pulses at 515 nm allows drilling and cutting of invar foil with 784 beams at once with high precision and almost no thermal effects and heat-affected zone, thus significantly improving the throughput and efficiency.

Generation of plasma-channels by interaction of gas targets with nanosecond laser beams was investigated experimentally. Such laser-generated plasma channels are very promising for subsequent guiding of high peak power femtosecond laser pulses, over several tens of centimeters, as required in laser wake field electron-acceleration (LWFA). The experimental setup was based on the use of a cylindrical lens (100 mm of focal length) with the aim of proposing a technical solution easy to be integrated into a compact experimental setup for acceleration of multi-GeV electron beams using high peak-power laser systems. A pilot experiment, showing production of asymmetric plasma channels over a length of several millimeters in N and Ar targets with initial neutral-gas atomic density around 5 × 1019 cm−3, is reported. Plasma effective threshold formation was estimated, along with future optimization of the optical setup for a symmetrization of such plasma channel. Scalability of this concept to several tens of centimeters is preliminarily discussed, along with the corresponding critical requirements for an optimal LWFA scheme.

An overview of the latest developments of kilowatt-level diode pumped solid state lasers for advanced applications at the HiLASE Centre is presented. An overview of subcontracted and in-house-developed laser beamlines is presented. The aim of development is to build kW-class beamlines delivering picosecond pulses between 1- and 100-kHz repetition rates and high-energy nanosecond pulses at 10 Hz. The picosecond beamlines are based on Yb:YAG thin-disk amplifiers and chirped pulse amplification. The current status of the beamlines’ performance is reported. The advantages of zero-phonon line and pulsed pumping are demonstrated with respect to efficiency, thin disk temperature and beam quality. New diagnostics methods supporting the high average power lasers’ development, such as the high-resolution spectroscopy of Yb-doped materials, in situ thin disk deformation measurements, single-shot M2 measurement, realization of wavefront correction by a deformable mirror and the laser performance of a new mixed garnet ceramics, are described. The energetic, thermal and fluid-mechanical numerical modeling for the optimization of the multi-slab amplifiers is also described.

We describe a compact Yb:YAG laser Q-switched by a graphene-based saturable absorber and pumped by a laser diode at 932 or 969 nm. The compact laser generates a maximum average output power value of 185 mW at 1032 nm with a slope efficiency value of 12%. The shortest duration of the Q-switched pulse achieved is 228 ns at a repetition frequency of 285 kHz. The maximum pulse energy amounts to 0.65 μJ.

We review the progress in the investigation of the Verdet constant of new magneto-active materials for the Faraday-effect-based devices used in high-power laser systems. A practical methodology for advanced characterization of the Verdet constant of these materials is presented, providing a useful tool for benchmarking the new materials. The experimental setup used for the characterization is a flexible and robust tool for evaluating the Faraday rotation angle induced in the magneto-active material, from which the Verdet constant is calculated based on the knowledge of the magnetic field and the material sample parameters. A general model for describing the measured Verdet constant data as a function of wavelength and temperature is given. In the final part of this review, we present a brief overview of several magneto-active materials, which have been to-date reported as promising candidates for utilization in the Faraday devices. This overview covers room-temperature investigations of the Verdet constant of several materials, which could be used for the ultraviolet, visible, near-infrared and mid-infrared wavelengths.

A hydrogeological and hydrochemical monitoring was conducted in the Pale di San Martino mountain ridge (Trento and Belluno Provinces, Italy) to build a preliminary conceptual model of the groundwater system. The model derives from a combination of new fieldwork and preexisting data provided by various public authorities. New data include geological and hydrogeological surveys, such as in situ measurements of the physical and chemical parameters, geochemical sampling and streamflow measurements. The lithologies outcropping in the area were grouped into seven hydrogeological complexes, each playing a different role in groundwater circulation. The dolomitic body of the ridges forms the main aquifer complex and is located above a terrigenous and evaporitic aquiclude. Due to this geometrical relationship, the site can be considered an isolated hydrostructure with well-defined no-flow boundaries. The main springs outcome near the aquifer-aquiclude boundary and in particular where the elevation of the contact is low and the tectonic pattern favors the drainage. Most of them have a calciumbicarbonate water composition, low temperature and low electrical conductivity, supporting the hypothesis of a fast flowing circulation in carbonate rocks and a high-altitude recharge. Seasonal streamflow measurements allowed the identification of linear springs and provided the first cumulative discharge data at the scale of the entire mountain group. The resulting model highlights a great spatial and temporal variability of the groundwater resources. Considering the geometry of the aquifer and the great seasonal variability of the discharge, it is possible to infer the absence of significant groundwater reserves at a regional scale. Thus, the hydrostructure shows a great capacity to supply water resources (mean discharge of 6 m3/s), but a low selfregulation capacity. It is necessary to consider this aspect when planning a long-term exploitation of the water resources that are used in the area for drinking purposes and hydropower generation.

The newly developed so call multy-slab laser at premise of the research centre HiLASE is already recognized as a potential new source for efficient laser surface treatments. Once the system is in full operation the pulses of up to 100J with pulse duration of 2-10 ns will be delivered with repetition rate of 10 Hz. In this paper the status of this new laser system is presented. Additionally the design of a new experimental station for laser surface treatments is also discussed. According to preliminary plans the station will be ready for first experiments in 2016.

Web-based surveys have become a common mode of data collection for researchers in many fields, but there are many methodological questions that need to be answered. This article examines one such question—do the use of sliders to express numerical amounts and the use of the more traditional radio-button scales give the same, or different, measurements? First, we review the central debates surrounding the use of slider scales, including advantages and disadvantages. Second, we report findings from a controlled simple randomized design field experiment using a sample of business managers in Italy to compare the two response formats. Measures of topic sensitivity, topic interest, and likelihood of participation were obtained. No statistically significant differences were found between the response formats. The article concludes with suggestions for researchers who wish to use slider scales as a measurement device.

We introduce the Czech national R&D project HiLASE which focuses on strategic development of advanced high-repetition rate, diode pumped solid state laser (DPSSL) systems that may find use in research, high-tech industry and in the future European large-scale facilities such as HiPER and ELI. Within HiLASE we explore two major concepts: thin-disk and cryogenically cooled multislab amplifiers capable of delivering average output powers above 1 kW level in picosecond-to-nanosecond pulsed regime. In particular, we have started a programme of technology development to demonstrate the scalability of multislab concept up to the kJ level at repetition rate of 1–10 Hz.

We present a comparison of two alternative laser layouts for HiLASE and ELI Beamlines projects. The cryogenically cooled laser is 100 J class with 2 ns pulse length and operates at 10 Hz repetition rate. The laser beam is intended for industrial applications in HiLASE, for OPCPA pumping in ELI Beamlines and can serve as a test bed for large scale high repetition rate fusion lasers. First layout utilizes classical scheme with preamplifier and main amplifier, while the second layout utilizes single amplifier scheme with two amplifier heads. The comparison is based on the results obtained from homemade MATLAB code for evaluation of amplified spontaneous emission and stored energy and on a beam propagation simulated in MIRÓ code.

A major challenge the HiPER [1] project is facing is to derive laser architectures satisfying simultaneously all HiPER requirements; among them, high wall-plug efficiency (15 to 20%) and repetition rate (around 10 Hz) are the most challenging constraints. Several groups over the world are actively pursuing research in the field of High average power Diode Pumped Solid State Lasers (DPSSL) [2]. We propose a comprehensive solution for a 1 kJ DPSSL beamline as the unit brick of a 12 beams bundle.