| 1. |
- Bastard, P, et al.
(författare)
-
Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs
- 2022
-
Ingår i: Science immunology. - : American Association for the Advancement of Science (AAAS). - 2470-9468. ; 78:7490, s. eabp8966-
-
Tidskriftsartikel (refereegranskat)abstract
- Life-threatening ‘breakthrough’ cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS-CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals (age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto-Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-α2 and IFN-ω, while two neutralized IFN-ω only. No patient neutralized IFN-β. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population.
|
|
| 2. |
|
|
| 3. |
- Apponi, A., et al.
(författare)
-
Heisenberg's uncertainty principle in the PTOLEMY project : A theory update
- 2022
-
Ingår i: Physical Review D. - : American Physical Society. - 2470-0010 .- 2470-0029. ; 106:5
-
Tidskriftsartikel (refereegranskat)abstract
- We discuss the consequences of the quantum uncertainty on the spectrum of the electron emitted by the beta-processes of a tritium atom bound to a graphene sheet. We analyze quantitatively the issue recently raised by Cheipesh, Cheianov, and Boyarsky [Phys. Rev. D 104, 116004 (2021)], and discuss the relevant timescales and the degrees of freedom that can contribute to the intrinsic spread in the electron energy. We perform careful calculations of the potential between tritium and graphene with different coverages and geometries. With this at hand, we propose possible avenues to mitigate the effect of the quantum uncertainty.
|
|
| 4. |
- Apponi, A., et al.
(författare)
-
Implementation and optimization of the PTOLEMY transverse drift electromagnetic filter
- 2022
-
Ingår i: Journal of Instrumentation. - : IOP Publishing Ltd. - 1748-0221. ; 17:5
-
Tidskriftsartikel (refereegranskat)abstract
- The PTOLEMY transverse drift filter is a new concept to enable precision analysis of the energy spectrum of electrons near the tritium beta-decay endpoint. This paper details the implementation and optimization methods for successful operation of the filter for electrons with a known pitch angle. We present the first demonstrator that produces the required magnetic field properties with an iron return-flux magnet. Two methods for the setting of filter electrode voltages are detailed. The challenges of low-energy electron transport in cases of low field are discussed, such as the growth of the cyclotron radius with decreasing magnetic field, which puts a ceiling on filter performance relative to fixed filter dimensions. Additionally, low pitch angle trajectories are dominated by motion parallel to the magnetic field lines and introduce non-adiabatic conditions and curvature drift. To minimize these effects and maximize electron acceptance into the filter, we present a three-potential-well design to simultaneously drain the parallel and transverse kinetic energies throughout the length of the filter. These optimizations are shown, in simulation, to achieve low-energy electron transport from a 1 T iron core (or 3 T superconducting) starting field with initial kinetic energy of 18.6 keV drained to < 10 eV (< 1 eV) in about 80 cm. This result for low field operation paves the way for the first demonstrator of the PTOLEMY spectrometer for measurement of electrons near the tritium endpoint to be constructed at the Gran Sasso National Laboratory (LNGS) in Italy.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Mineo Bianchi, F, et al.
(författare)
-
Posterior muscle-fascial reconstruction and knotless urethro-neo bladder anastomosis during robot-assisted radical cystectomy: Description of the technique and its impact on urinary continence
- 2019
-
Ingår i: Archivio italiano di urologia, andrologia : organo ufficiale [di] Societa italiana di ecografia urologica e nefrologica. - : PAGEPress Publications. - 2282-4197. ; 91:1, s. 5-10
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of our study is to describe the use of posterior muscle-fascial reconstruction during urethro-ileal anastomosis in bladder cancer (BC) patients submitted to robot-assisted radical cystectomy (RC) with orthotopic neobladder (ON) and its role in facilitating day- and night-time continence recovery during a 12-month follow up. Materials and methods: We prospectively collected data from 42 consecutive patients who underwent RARC with totally intracorporeal ON and extended pelvic lymph node dissection (PLND) at our Institution from June 2014 to October 2017. Prior to the urethro-neobladder anastomosis we reconstructed the Denonvilliers Fascia (DF) as previously described for radical prostatectomy using a bidirectional barbed suture. Day and night-time recovery rates were reported at 3, 6 and 12 months after surgery, with continent patients being those using either no urinary pads or 1 safety pads. Results: Median age at surgery was 63 yrs, 41 (97.6%) patients were male. 28 (66.7%) patients presented a clinical T2 disease. Median operative time and median ON reconstruction time were 450 minutes and 180 minutes respectively. 13 (31%) individuals had non-organ confined disease, with 11 (26.2%) patients with positive lymph nodes (median 3 positive lymph nodes) and 2 (4.8%) with non-urothelial cancer at final pathologic examination. Median hospital stay and median catheterization time were 7 (IQR 7-8) and 21 (IQR 19-22). During first 30 post-operative days we recorded 7 (16.7%) low-grade Clavien and 2 (4.8%) IIIa Clavien complications, whereas between 30 and 90 postoperative days we recorded 4 (9.5%) low-grade, 4 (9.5) IIIa and 1 (2.4%) IIIb complications. Day-time and night-time continence rates were 61.9% vs 52.4%, 73.8% vs 64.3% and 90.5% vs 73.8% at three, six and twelve months follow up. Day-time continence was significantly superior in the younger group (97% vs 57%, p 0.01); night-time continence rates were also superior among < 70 yrs patients, despite not reaching statistical significance (77% vs 57%, p 0.3). Conclusions: Posterior muscle-fascial reconstruction aids continence recovery in BC patients undergoing RARC with ON, with younger and fitter patients most benefitting from ON reconstruction.
|
|
| 8. |
- Quinn, K., et al.
(författare)
-
Weibel-Induced Filamentation during an Ultrafast Laser-Driven Plasma Expansion
- 2012
-
Ingår i: Physical Review Letters. - American Physical Society. - 0031-9007 .- 1079-7114. ; 108:13, s. 135001-
-
Tidskriftsartikel (refereegranskat)abstract
- The development of current instabilities behind the front of a cylindrically expanding plasma has been investigated experimentally via proton probing techniques. A multitude of tubelike filamentary structures is observed to form behind the front of a plasma created by irradiating solid-density wire targets with a high-intensity (I∼1019 W/cm2), picosecond-duration laser pulse. These filaments exhibit a remarkable degree of stability, persisting for several tens of picoseconds, and appear to be magnetized over a filament length corresponding to several filament radii. Particle-in-cell simulations indicate that their formation can be attributed to a Weibel instability driven by a thermal anisotropy of the electron population. We suggest that these results may have implications in astrophysical scenarios, particularly concerning the problem of the generation of strong, spatially extended and sustained magnetic fields in astrophysical jets.
|
|
| 9. |
- Sarri, Gianluca, et al.
(författare)
-
Dynamics of Self-Generated, Large Amplitude Magnetic Fields Following High-Intensity Laser Matter Interaction
- 2012
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 109:20, s. 205002-
-
Tidskriftsartikel (refereegranskat)abstract
- The dynamics of magnetic fields with an amplitude of several tens of megagauss, generated at both sides of a solid target irradiated with a high-intensity (∼1019 W/cm2) picosecond laser pulse, has been spatially and temporally resolved using a proton imaging technique. The amplitude of the magnetic fields is sufficiently large to have a constraining effect on the radial expansion of the plasma sheath at the target surfaces. These results, supported by numerical simulations and simple analytical modeling, may have implications for ion acceleration driven by the plasma sheath at the rear side of the target as well as for the laboratory study of self-collimated high-energy plasma jets.
|
|
| 10. |
- Warwick, J., et al.
(författare)
-
Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam
- 2017
-
Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 119:18
-
Tidskriftsartikel (refereegranskat)abstract
- We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (amp;gt;= 1 T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of epsilon(B) approximate to 10(-3) is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.
|
|
| 11. |
- Borghesi, M., et al.
(författare)
-
Progress in proton radiography for diagnosis of ICF-relevant plasmas
- 2010
-
Ingår i: Laser and particle beams (Print). - 0263-0346 .- 1469-803X. ; 28:2, s. 277-284
-
Tidskriftsartikel (refereegranskat)abstract
- Proton radiography using laser-driven sources has been developed as a diagnostic since the beginning of the decade, and applied successfully to a range of experimental situations. Multi-MeV protons driven from thin foils via the Target Normal Sheath Acceleration mechanism, offer, under optimal conditions, the possibility of probing laser-plasma interactions, and detecting electric and magnetic fields as well as plasma density gradients with similar to ps temporal resolution and similar to 5-10 mu m spatial resolution. In view of these advantages, the use of proton radiography as a diagnostic in experiments of relevance to Inertial Confinement Fusion is currently considered in the main fusion laboratories. This paper will discuss recent advances in the application of laser-driven radiography to experiments of relevance to Inertial Confinement Fusion. In particular we will discuss radiography of hohlraum and gasbag targets following the interaction of intense ns pulses. These experiments were carried out at the HELEN laser facility at AWE (UK), and proved the suitability of this diagnostic for studying, with unprecedented detail, laser-plasma interaction mechanisms of high relevance to Inertial Confinement Fusion. Non-linear solitary structures of relevance to space physics, namely phase space electron holes, have also been highlighted by the measurements. These measurements are discussed and compared to existing models.
|
|
| 12. |
- Dieckmann, Mark E, et al.
(författare)
-
Electrostatic shock waves in the laboratory and astrophysics: similarities and differences
- 2018
-
Ingår i: Plasma Physics and Controlled Fusion. - : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 60:1
-
Tidskriftsartikel (refereegranskat)abstract
- Contemporary lasers allow us to create shocks in the laboratory that propagate at a speed that matches that of energetic astrophysical shocks like those that ensheath supernova blast shells. The rapid growth time of the shocks and the spatio-temporal resolution, with which they can be sampled, allow us to identify the processes that are involved in their formation and evolution. Some laser-generated unmagnetized shocks are mediated by collective electrostatic forces and effects caused by binary collisions between particles can be neglected. Hydrodynamic models, which are valid for many large-scale astrophysical shocks, assume that collisions enforce a local thermodynamic equilibrium in the medium; laser-generated shocks are thus not always representative for astrophysical shocks. Laboratory studies of shocks can improve the understanding of their astrophysical counterparts if we can identify processes that affect electrostatic shocks and hydrodynamic shocks alike. An example is the nonlinear thin-shell instability (NTSI). We show that the NTSI destabilises collisionless and collisional shocks by the same physical mechanism.
|
|
| 13. |
- Dieckmann, Mark E, et al.
(författare)
-
Thin-shell instability in collisionless plasma
- 2015
-
Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society. - 1539-3755 .- 1550-2376. ; 92:3, s. 031101-
-
Tidskriftsartikel (refereegranskat)abstract
- Thin-shell instability is one process which can generate entangled structures in astrophysical plasma on collisional (fluid) scales. It is driven by a spatially varying imbalance between the ram pressure of the inflowing upstream plasma and the downstreams thermal pressure at a nonplanar shock. Here we show by means of a particle-in-cell simulation that an analog process can destabilize a thin shell formed by two interpenetrating, unmagnetized, and collisionless plasma clouds. The amplitude of the shells spatial modulation grows and saturates after about ten inverse proton plasma frequencies, when the shell consists of connected piecewise linear patches.
|
|
| 14. |
- Sarri, G, et al.
(författare)
-
The application of laser-driven proton beams to the radiography of intense laser–hohlraum interactions
- 2010
-
Ingår i: New Journal of Physics. - : IOP Publishing Ltd. - 1367-2630. ; 12:4, s. 045006-
-
Tidskriftsartikel (refereegranskat)abstract
- Plasma expansion following the interaction of an intense laser beam with the inner surface of gold hohlraums, emulating conditions relevant to indirect drive inertial confinement fusion (ICF), has been investigated by a radiographic technique which employs a beam of laser-accelerated protons. This probing technique has made it possible to measure the electric field distribution associated with the plasma front and its propagation throughout the interior of the hohlraum with a temporal and spatial resolution of the order of a few ps and μm, respectively. The data indicate that the expanding plasma slows down approaching the opposite walls, possibly due to the interaction with x-ray heated plasma from the non-irradiated walls. The electric field at the plasma front shows a bipolar structure, suggesting the presence of ion-acoustic soliton-like structures cotraveling with the front. Data obtained using enclosed hohlraums suggest the feasibility of this type of diagnosis in gas-filled hohlraums, as currently employed in ICF experiments.
|
|
