Acceleration and focusing of relativistic electron beams in a compact plasma device.

Plasma wakefield acceleration represented a breakthrough in the field of particle accelerators by pushing beams to gigaelectronvolt energies within centimeter distances. The large electric fields excited by a driver pulse in the plasma can efficiently accelerate a trailing witness bunch paving the way toward the realization of laboratory-scale applications like free-electron lasers. However, while the accelerator size is tremendously reduced, upstream and downstream of it the beams are still handled with conventional magnetic optics with sizable footprints and rather long focal lengths. Here we show the operation of a compact device that integrates two active-plasma lenses with short focal lengths to assist the plasma accelerator stage. We demonstrate the focusing and energy gain of a witness bunch whose phase space is completely characterized in terms of energy and emittance. These results represent an important step toward the accelerator miniaturization and the development of next-generation table-top machines.

Guiding of Charged Particle Beams in Curved Plasma-Discharge Capillaries.

We present a new approach that demonstrates the deflection and guiding of relativistic electron beams over curved paths by means of the magnetic field generated in a plasma-discharge capillary. We experimentally prove that the guiding is much less affected by the beam chromatic dispersion with respect to a conventional bending magnet and, with the support of numerical simulations, we show that it can even be made dispersionless by employing larger discharge currents. This proof-of-principle experiment extends the use of plasma-based devices, that revolutionized the field of particle accelerators enabling the generation of GeV beams in few centimeters. Compared to state-of-the-art technology based on conventional bending magnets and quadrupole lenses, these results provide a compact and affordable solution for the development of next-generation tabletop facilities.

Effect of different therapeutic strategies on olfactory outcomes in patients with chronic rhinosinusitis with nasal polyps: a systematic review.

INTRODUCTION: Olfactory impairment is one of the cardinal symptoms of chronic rhinosinusitis with nasal polyps (CRSwNP), yet the effect of the currently available therapeutic options on the recovery of the sense of smell is not well defined. The aim of this systematic review was to compile the evidence on the impact of medical, surgical, and biological therapies on the olfactory outcomes in patients with CRSwNP. METHODS: This review was conducted by two reviewers, according to the Preferred Reporting Items for Systematic Reviews and meta-Analyses (PRISMA) guidelines. The quality of evidence of all studies included in the qualitative synthesis was evaluated using the Critical Appraisal Skills Programme (CASP). RESULTS: Forty-four studies were included in the qualitative synthesis (assessing sinonasal surgery [n = 23], biologics [n =15], and conventional medical treatment [n = 6]); most had moderate-to-high methodological quality. Overall, significant improvements in the sense of smell were detected with all analyzed interventions measured by either an objective or a subjective tool (or both). However, most studies used different outcome measurements, hindering comparisons between interventions, and data on clinically relevant changes were missing. CONCLUSION: Oral corticosteroids, biologics and sinonasal surgery improve olfactory impairment associated with CRSwNP, but the high variability among existing studies does not allow accurate comparisons.

Stable Operation of a Free-Electron Laser Driven by a Plasma Accelerator.

The breakthrough provided by plasma-based accelerators enabled unprecedented accelerating fields by boosting electron beams to gigaelectronvolt energies within a few centimeters [1-4]. This, in turn, allows the realization of ultracompact light sources based on free-electron lasers (FELs) [5], as demonstrated by two pioneering experiments that reported the observation of self-amplified spontaneous emission (SASE) driven by plasma-accelerated beams [6,7]. However, the lack of stability and reproducibility due to the intrinsic nature of the SASE process (whose amplification starts from the shot noise of the electron beam) may hinder their effective implementation for user purposes. Here, we report a proof-of-principle experiment using plasma-accelerated beams to generate stable and reproducible FEL light seeded by an external laser. FEL radiation is emitted in the infrared range, showing the typical exponential growth of its energy over six consecutive undulators. Compared to SASE, the seeded FEL pulses have energies 2 orders of magnitude larger and stability that is 3 times higher.

Free-electron lasing with compact beam-driven plasma wakefield accelerator.

The possibility to accelerate electron beams to ultra-relativistic velocities over short distances by using plasma-based technology holds the potential for a revolution in the field of particle accelerators1-4. The compact nature of plasma-based accelerators would allow the realization of table-top machines capable of driving a free-electron laser (FEL)5, a formidable tool to investigate matter at the sub-atomic level by generating coherent light pulses with sub-ångström wavelengths and sub-femtosecond durations6,7. So far, however, the high-energy electron beams required to operate FELs had to be obtained through the use of conventional large-size radio-frequency (RF) accelerators, bound to a sizeable footprint as a result of their limited accelerating fields. Here we report the experimental evidence of FEL lasing by a compact (3-cm) particle-beam-driven plasma accelerator. The accelerated beams are completely characterized in the six-dimensional phase space and have high quality, comparable with state-of-the-art accelerators8. This allowed the observation of narrow-band amplified radiation in the infrared range with typical exponential growth of its intensity over six consecutive undulators. This proof-of-principle experiment represents a fundamental milestone in the use of plasma-based accelerators, contributing to the development of next-generation compact facilities for user-oriented applications9.

Iatrogenic atrial septal defect does not affect acute hemodynamic modifications after transcatheter edge-to-edge repair in patients with functional mitral regurgitation.

OBJECTIVE: The correction of functional mitral regurgitation (FMR) with transcatheter edge-to-edge repair (TEER) can favorably affect patients' hemodynamic profile. However, the procedure requires inter-atrial trans-septal access and the hemodynamic relevance of the residual iatrogenic atrium septal defect (iASD) is still debated. This study aimed at investigating the hemodynamic modifications during TEER with MitraClip, before and after the iASD creation, in patients with heart failure with reduced ejection fraction (HFrEF) and severe FMR. METHODS: Thirty-nine HFrEF patients with 3+ or 4+/4+ FMR were included. Right heart catheterization was performed at baseline after general anesthesia induction and at the end of TEER, both before and after removing the device guiding catheter. RESULTS: Compared with baseline, MitraClip positioning was followed by a significant immediate improvement in cardiac output (respectively: 3.36 vs 5.05 ml/min), pulmonary artery wedge pressure (23.7 vs 18.2 mmHg), mean pulmonary artery pressure (34.4 vs 27.7 mmHg) and pulmonary vascular resistance (3.6 vs 2.2 Wood Units) (all p < 0.001). No further significant modifications occurred after removing the device guiding catheter. CONCLUSIONS: Our data suggest that the acute hemodynamic modifications after TEER are not influenced by the induction of iASD in patients with FMR.

Anti-SARS-CoV-2 antibody levels and kinetics of vaccine response: potential role for unresolved inflammation following recovery from SARS-CoV-2 infection.

The immune response after SARS-CoV-2 vaccine administration appears to be characterized by high inter-individual variation, even in SARS-CoV-2 positive subjects, who could have experienced different post-infection, unresolved conditions. We monitored anti-SARS-CoV-2 IgG levels and kinetics along with circulating biomarkers in a cohort of 175 healthcare workers during early immunization with COVID-19 mRNA-LNP BNT162b2 vaccine, to identify the associated factors. Subjects with a previous SARS-CoV-2 infection were characterized by higher BMI and CRP levels and lower neutrophil count with respect to naïve subjects. Baseline IgG levels resulted associated with CRP independently on BMI and inflammatory diseases. Among 137 subjects undergoing vaccination and monitored after the first and the second dose, three kinetic patterns were identified. The pattern showing a rapid growth was characterized by higher IgG levels at baseline and higher CRP and MCHC levels than negative subjects. Subjects previously exposed to SARS-CoV-2 showed higher levels of CRP, suggesting persistence of unresolved inflammation. These levels are the main determinant of IgG levels at baseline and characterized subjects belonging to the best performing, post-vaccine antibody kinetic pattern.

Time-resolved study of nonlinear photoemission in radio-frequency photoinjectors.

Photoemission is one of the fundamental processes that describes the generation of charged particles from materials irradiated by photons. The continuous progress in the development of ultrashort lasers allows investigation into the dynamics of the process at the femtosecond timescale. Here we report about experimental measurements using two ultrashort ultraviolet laser pulses to temporally probe the electrons release from a copper cathode in a radio-frequency photoinjector. By changing their relative delay, we studied how the release mechanism is affected by two-photon photoemission when tens of GW/cm2 intensities are employed. We evaluated the limits it poses on the achievable beam brightness and analyzed the resulting emission yield in terms of the electronic temperature by modeling the cathode as a two-temperature system.

Accurate spectra for high energy ions by advanced time-of-flight diamond-detector schemes in experiments with high energy and intensity lasers.

Time-Of-Flight (TOF) methods are very effective to detect particles accelerated in laser-plasma interactions, but they show significant limitations when used in experiments with high energy and intensity lasers, where both high-energy ions and remarkable levels of ElectroMagnetic Pulses (EMPs) in the radiofrequency-microwave range are generated. Here we describe a novel advanced diagnostic method for the characterization of protons accelerated by intense matter interactions with high-energy and high-intensity ultra-short laser pulses up to the femtosecond and even future attosecond range. The method employs a stacked diamond detector structure and the TOF technique, featuring high sensitivity, high resolution, high radiation hardness and high signal-to-noise ratio in environments heavily affected by remarkable EMP fields. A detailed study on the use, the optimization and the properties of a single module of the stack is here described for an experiment where a fast diamond detector is employed in an highly EMP-polluted environment. Accurate calibrated spectra of accelerated protons are presented from an experiment with the femtosecond Flame laser (beyond 100 TW power and ~ 1019 W/cm2 intensity) interacting with thin foil targets. The results can be readily applied to the case of complex stack configurations and to more general experimental conditions.

Ultrafast electron and proton bunches correlation in laser-solid matter experiments.

The interaction of an ultra-intense laser with a solid state target allows the production of multi-MeV proton and ion beams. This process is explained by the target normal sheath acceleration (TNSA) model, predicting the creation of an electric field on the target rear side, due to an unbalanced positive charge. This process is related to the emission of relativistic ultrafast electrons, occurring at an earlier time. In this work, we highlight the correlations between the ultrafast electron component and the protons by their simultaneous detection by means of an electro-optical sampling and a time-of-flight diagnostics, respectively, supported by numerical simulations showing an excellent agreement.

Time-resolved characterization of ultrafast electrons in intense laser and metallic-dielectric target interaction.

High-intensity ultrashort laser pulses interacting with thin solid targets are able to produce energetic ion beams by means of extremely large accelerating fields set by the energetic ejected electrons. The characterization of such electrons is thus important in view of a complete understanding of the acceleration process. Here, we present a complete temporal-resolved characterization of the fastest escaping hot electron component for different target materials and thicknesses, using temporal diagnostics based on electro-optical sampling with 100 fs temporal resolution. Experimental evidence of scaling laws for ultrafast electron beam parameters have been retrieved with respect to the impinging laser energy (0.4-4 J range) and to the target material, and an empirical law determining the beam parameters as a function of the target thickness is presented.

Modeling and diagnostics for plasma discharge capillaries.

In this paper, we show how plasma discharge capillaries can be numerically modeled as resistors within an RLC-series discharge circuit, allowing for a simple description of these systems, while taking into account heat and radiation losses. An analytic radial model is also provided and compared to the numerical model for plasma discharge capillaries at thermal equilibrium, with corrections due to radiation losses. Finally, diagnostic techniques based on visible spectroscopy of plasma emission lines are discussed both for atomic and molecular gases, comparing experimental results with numerical simulations and theoretical calculations.

Longitudinal Phase-Space Manipulation with Beam-Driven Plasma Wakefields.

The development of compact accelerator facilities providing high-brightness beams is one of the most challenging tasks in the field of next-generation compact and cost affordable particle accelerators, to be used in many fields for industrial, medical, and research applications. The ability to shape the beam longitudinal phase space, in particular, plays a key role in achieving high-peak brightness. Here we present a new approach that allows us to tune the longitudinal phase space of a high-brightness beam by means of plasma wakefields. The electron beam passing through the plasma drives large wakefields that are used to manipulate the time-energy correlation of particles along the beam itself. We experimentally demonstrate that such a solution is highly tunable by simply adjusting the density of the plasma and can be used to imprint or remove any correlation onto the beam. This is a fundamental requirement when dealing with largely time-energy correlated beams coming from future plasma accelerators.

Focusing of High-Brightness Electron Beams with Active-Plasma Lenses.

Plasma-based technology promises a tremendous reduction in size of accelerators used for research, medical, and industrial applications, making it possible to develop tabletop machines accessible for a broader scientific community. By overcoming current limits of conventional accelerators and pushing particles to larger and larger energies, the availability of strong and tunable focusing optics is mandatory also because plasma-accelerated beams usually have large angular divergences. In this regard, active-plasma lenses represent a compact and affordable tool to generate radially symmetric magnetic fields several orders of magnitude larger than conventional quadrupoles and solenoids. However, it has been recently proved that the focusing can be highly nonlinear and induce a dramatic emittance growth. Here, we present experimental results showing how these nonlinearities can be minimized and lensing improved. These achievements represent a major breakthrough toward the miniaturization of next-generation focusing devices.

3D-printed capillary for hydrogen filled discharge for plasma based experiments in RF-based electron linac accelerator.

Plasma-based acceleration experiments require capillaries with a radius of a few hundred microns to confine plasma up to a centimeter scale capillary length. A long and controlled plasma channel allows to sustain high fields which may be used for manipulation of the electron beams or to accelerate electrons. The production of these capillaries is relatively complicated and expensive since they are usually made with hard materials whose manufacturing requires highly specialized industries. Fine variations of the capillary shape may significantly increase the cost and time needed to produce them. In this article, we demonstrate the possibility of using 3D printed polymeric capillaries to drive a hydrogen-filled plasma discharge up to 1 Hz of repetition rate in an RF based electron linac. The plasma density distribution has been measured after several shot intervals, showing the effect of the surface ablation on the plasma density distribution. This effect is almost invisible in the earlier stages of the discharge. After more than 55000 shots (corresponding to more than 16 h of working time), the effects of the ablation on the plasma density distribution are not evident and the capillary can still be used. The use of these capillaries will significantly reduce the cost and time for prototyping, allowing us to easily manipulate their geometry, laying another building block for future cheap and compact particle accelerators.

Psoriasis and the risk of acute coronary syndrome in the elderly.

BACKGROUND: Psoriasis has been associated with a higher prevalence of cardiovascular disease risk factors. However, there is inadequate quantification on the association between psoriasis and acute coronary syndrome (ACS), particularly in the elderly. Therefore, the aim of the present study was to assess the risk of ACS according to history of psoriasis in subjects aged 75 years and older. METHODS: We carried out a case control study based on 1455 cases and 1108 controls. Cases were all the patients admitted in the randomized Elderly ACS 2 trial. Controls were selected from subjects aged ≥75 years included in the Prevalence of Actinic Keratoses in the Italian Population Study (PraKtis), based on a representative sample of the general Italian population. Odds ratios (OR) of ACS according to history of psoriasis were obtained using a multiple logistic regression model including terms for age, sex and smoking. RESULTS: The prevalence of psoriasis was lower among cases (12/1455, 0.8%) than among controls (18/1108, 1.6%). The multivariate OR of ACS according to history of psoriasis was 0.51 (95% confidence interval: 0.23-1.09). CONCLUSIONS: Our data does not support an association between psoriasis and risk of ACS in the elderly.

Development and quality assessment of a turbid carrot-orange juice blend processed by UV-C light assisted by mild heat and addition of Yerba Mate (Ilex paraguariensis) extract.

Carrot-orange juice processed by UV-C (10.6 kJ/m2) assisted with mild heat (H, 50 °C) and yerba mate addition (E) was obtained. UV-C/H + E treated juice was examined for native flora, polyphenol content (PC), total antioxidant activity (TAA), colour, turbidity, °Brix and pH along storage (4 °C). Consumer profiling studies were performed. UV-C/H + E provoked 2.6-5.7 native flora log reductions, preventing from recovery during 24 day-storage. The UV-C/H + E juice exhibited a significant increase in PC (720.2 µg/mL) and TAA (5.5 mg/mL) compared to untreated (PC = 205.0 µg/mL/TAA = 0.7 mg/mL) and single treated juices (PC = 302.1-408.0 µg/mL/TAA = 0.7-2.4 mg/mL), remaining constant throughout storage. UV-C/H + E juice exhibited scarce changes in colour. Nevertheless, increases in °Brix and turbidity were observed compared to single treatments. A cluster sensory analysis revealed that one group showed a marked interest in UVC/H + E beverages with herbal taste and strong aroma. CATA question revealed that some improvements should be introduced in order to satisfy the consumers' ideally beverage.

Compact and tunable focusing device for plasma wakefield acceleration.

Plasma wakefield acceleration, either driven by ultra-short laser pulses or electron bunches, represents one of the most promising techniques able to overcome the limits of conventional RF technology and allows the development of compact accelerators. In the particle beam-driven scenario, ultra-short bunches with tiny spot sizes are required to enhance the accelerating gradient and preserve the emittance and energy spread of the accelerated bunch. To achieve such tight transverse beam sizes, a focusing system with short focal length is mandatory. Here we discuss the development of a compact and tunable system consisting of three small-bore permanent-magnet quadrupoles with 520 T/m field gradient. The device has been designed in view of the plasma acceleration experiments planned at the SPARC_LAB test-facility. Being the field gradient fixed, the focusing is adjusted by tuning the relative position of the three magnets with nanometer resolution. Details about its magnetic design, beam-dynamics simulations, and preliminary results are examined in the paper.

Ultrafast evolution of electric fields from high-intensity laser-matter interactions.

The interaction of high-power ultra-short lasers with materials offers fascinating wealth of transient phenomena which are in the core of novel scientific research. Deciphering its evolution is a complicated task that strongly depends on the details of the early phase of the interaction, which acts as complex initial conditions. The entire process, moreover, is difficult to probe since it develops close to target on the sub-picosecond timescale and ends after some picoseconds. Here we present experimental results related to the fields and charges generated by the interaction of an ultra-short high-intensity laser with metallic targets. The temporal evolution of the interaction is probed with a novel femtosecond resolution diagnostics that enables the differentiation of the contribution by the high-energy forerunner electrons and the radiated electromagnetic pulses generated by the currents of the remaining charges on the target surface. Our results provide a snapshot of huge pulses, up to 0.6 teravolt per meter, emitted with multi-megaelectronvolt electron bunches with sub-picosecond duration and are able to explore the processes involved in laser-matter interactions at the femtosecond timescale.