CERN-based experiments and Monte-Carlo studies on focused dose delivery with very high energy electron (VHEE) beams for radiotherapy applications.

Very High Energy Electron (VHEE) beams are a promising alternative to conventional radiotherapy due to their highly penetrating nature and their applicability as a modality for FLASH (ultra-high dose-rate) radiotherapy. The dose distributions due to VHEE need to be optimised; one option is through the use of quadrupole magnets to focus the beam, reducing the dose to healthy tissue and allowing for targeted dose delivery at conventional or FLASH dose-rates. This paper presents an in depth exploration of the focusing achievable at the current CLEAR (CERN Linear Electron Accelerator for Research) facility, for beam energies >200 MeV. A shorter, more optimal quadrupole setup was also investigated using the TOPAS code in Monte Carlo simulations, with dimensions and beam parameters more appropriate to a clinical situation. This work provides insight into how a focused VHEE radiotherapy beam delivery system might be achieved.

Evaluating very high energy electron RBE from nanodosimetric pBR322 plasmid DNA damage.

This paper presents the first plasmid DNA irradiations carried out with Very High Energy Electrons (VHEE) over 100-200 MeV at the CLEAR user facility at CERN to determine the Relative Biological Effectiveness (RBE) of VHEE. DNA damage yields were measured in dry and aqueous environments to determine that ~ 99% of total DNA breaks were caused by indirect effects, consistent with other published measurements for protons and photons. Double-Strand Break (DSB) yield was used as the biological endpoint for RBE calculation, with values found to be consistent with established radiotherapy modalities. Similarities in physical damage between VHEE and conventional modalities gives confidence that biological effects of VHEE will also be similar-key for clinical implementation. Damage yields were used as a baseline for track structure simulations of VHEE plasmid irradiation using GEANT4-DNA. Current models for DSB yield have shown reasonable agreement with experimental values. The growing interest in FLASH radiotherapy motivated a study into DSB yield variation with dose rate following VHEE irradiation. No significant variations were observed between conventional and FLASH dose rate irradiations, indicating that no FLASH effect is seen under these conditions.

Erratum: Emittance Preservation in an Aberration-Free Active Plasma Lens [Phys. Rev. Lett. 121, 194801 (2018)].

This corrects the article DOI: 10.1103/PhysRevLett.121.194801.

Emittance Preservation in an Aberration-Free Active Plasma Lens.

Active plasma lensing is a compact technology for strong focusing of charged particle beams, which has gained considerable interest for use in novel accelerator schemes. While providing kT/m focusing gradients, active plasma lenses can have aberrations caused by a radially nonuniform plasma temperature profile, leading to degradation of the beam quality. We present the first direct measurement of this aberration, consistent with theory, and show that it can be fully suppressed by changing from a light gas species (helium) to a heavier gas species (argon). Based on this result, we demonstrate emittance preservation for an electron beam focused by an argon-filled active plasma lens.

Ultra-dense WDM-PON 6.25 GHz spaced 8×1 Gb/s based on a simplified coherent-detection scheme.

We demonstrate experimentally a novel type of coherent low cost Gigabit-to-the-User Ultra-Dense-Wavelength Division Multiplexing (UD-WDM) PON, featuring 6.25 GHz channel spacing and long reach. Polarization-independent coherent detection is achieved by exploiting a novel scheme which requires only a 3 × 3 coupler, three photodiodes, basic analogue processing and a common DFB as local oscillator (LO). This avoids the conventional polarization diversity approach. The DFB LO is free running, i.e. not locked in frequency, and is tuned to detect any of the eight channels by simply changing its temperature in a range of 2° C. We achieve 70 km long-reach transmission plus 30 dB attenuation, for a total of > 45 dB optical distribution network loss. This indicates that this solution could be effectively exploited to overlay existing PON infrastructures by UD-WDM.

Puente adhesivo en paciente con labio leporino y fisura velopalatina: una solución temporal con compromiso estético / Adhesive bridge in a patient with cleft lip and palate: a temporary solution with esthetic commitment

En la actualidad el aumento de la demanda estética y la necesidad de procedimientos mínimamente invasivos ha llevado a un aumento de la técnica adhesiva. Ribbond® es una marca de fibra de polietileno que permite un eficiente traspaso de fuerzas, es virtualmente plegable y se adapta fácilmente a la morfología dentaria y al contorno del arco dentario. Dentro de sus principales características podemos encontrar: Biocompatibilidad, inerte, translúcido y durable. Dentro de la odontología se le han dado distintos usos para esta fibra, ya sea como mantenedor de espacio, puente adhesivo, poste y núcleo endodóntico, ferulización, restauraciones tipo inlay y estabilización postortodóncica. En el caso de los pacientes fisurados se ha hecho relevante el uso de Ribbond® como puente adhesivo ya que permite mejorar la estética y rehabilitar temporalmente los espacios desdentados causados por la ausencia de un incisivo, principalmente una vez terminado el tratamiento de ortodoncia y en espera de una rehabilitación definitiva, aún más cuando el paciente no ha terminado su crecimiento y desarrollo. En este artículo se presenta un caso clínico de un paciente con labio leporino y fisura velopalatina operado demostrativo de la técnica de rehabilitación con Ribbond®.

Today the increasing demand of aesthetic and minimally invasive procedures has led to a boom of the adhesive technique. Ribbond® is a polyethylene fiber that allows an efficient transfer of forces, is virtually foldable and is easily adapted to tooth morphology and dental arch contour. Among its main features we can find: Biocompatibility, inert, translucent and durable. In dentistry, different uses have been given to this fiber, whether as space maintainer, adhesive bridge, endodontic post and core, splinting, inlay type restorations and postorthodontic stabilization. In the case of cleft lip and palate patients the use of Ribbond® as an adhesive bridge has become relevant, as it improves aesthetics and temporarily rehabilitates the edentulous spaces caused by the absence of an incisor. It is used especially after completion of the orthodontic treatment and waiting for a final rehabilitation, even when the patient has not completed their growth and development. This article presents a clinical case of a patient with lip and cleft palate operated with the rehabilitation technique using Ribbond®.

3.4 Gbit/s visible optical wireless transmission based on RGB LED.

In this paper, we experimentally realized a gigabit-class indoor visible light communication system using commercially available RGB White LED and exploiting an optimized DMT modulation. We achieved data rate of 1.5 Gbit/s with single channel and 3.4 Gbit/s by implementing WDM transmission at standard illumination levels. In both experiments, the resulting bit error ratios were below the FEC limit. To the best of our knowledge, these values are the highest ever achieved in VLC systems.

Enhanced 10 Gb/s operations of directly modulated reflective semiconductor optical amplifiers without electronic equalization.

We report enhanced 10 Gb/s operation of directly modulated bandwidth-limited reflective semiconductor optical amplifiers. By using a single suitable arrayed waveguide grating we achieve simultaneously WDM demultiplexing and optical equalization. Compared to previous approaches, the proposed system results significantly more tolerant to seeding wavelength drifts. This removes the need for wavelength lockers, additional electronic equalization or complex digital signal processing. Uniform C-band operations are obtained experimentally with < 2 dB power penalty within a wavelength drift of 10 GHz (which doubles the ITU-T standard recommendations).

Emittance growth during bunch compression in the CTF-II

Measurements of the beam emittance during bunch compression in the CLIC Test Facility (CTF-II) are described. The measurements were made with different beam charges and different energy correlations versus the bunch compressor settings which were varied from no compression through the point of full compression and to overcompression. Significant increases in the beam emittance were observed with the maximum emittance occurring near the point of full (maximal) compression. Finally, evaluation of possible emittance dilution mechanisms indicates that coherent synchrotron radiation was the most likely cause.

Time-domain Fourier optics for polarization-mode dispersion compensation.

We report on a novel technique to compensate for all-order polarization-mode dispersion. By means of this technique, based on a suitable combination of phase modulation and group-velocity dispersion, we compensated for as much as 60 ps of differential group delay that affected a 10-Gbit/s return-to-zero data stream.

REM sleep behaviour disorder differentiates pure autonomic failure from multiple system atrophy with autonomic failure.

Ten patients with primary autonomic failure, followed up in a prospective clinical and laboratory study, were finally diagnosed as pure autonomic failure or multiple system atrophy with autonomic failure. Polysomnographic studies were performed in all patients. Whereas all four patients with multiple system atrophy complained of sleep related episodes suggesting REM sleep behaviour disorder (RBD) confirmed by polysomnography, RBD remained absent in the remaining six patients with pure autonomic failure. The data indicate that RBD is an important clinical feature, often heralding multiple system atrophy, but which is absent throughout the course of pure autonomic failure; its recognition can thus be useful in the prognostic evaluation of early primary autonomic failure syndromes.

Maturation of phagosomes is accompanied by changes in their fusion properties and size-selective acquisition of solute materials from endosomes.

Maturation of phagosomes is characterized by changes in their polypeptides, phosphorylated proteins and phospholipid composition. Kinetic analyses have shown that a variety of proteins associate and dissociate from latex-containing phagosomes at precise intervals during phagolysosome biogenesis. In an attempt to link these temporal biochemical modifications to functional changes, we have examined the in vivo fusion properties of aging endosomes and phagosomes. Using an in vivo fusion assay at the electron microscope, we measured the rate of exchange of bovine serum albumin-gold (5 and 16 nm particles) between endosomes and latex-bead-containing phagosomes. The results obtained indicate that the maturation of phagosomes is accompanied by changes of their fusion properties. Early phagosomes were shown to fuse preferentially with early endocytic organelles and to gradually acquire the ability to fuse with late endocytic organelles. Furthermore, the transfer of bovine serum albumin-gold from endosomes to phagosomes is size-dependent, a process also modulated by the maturation of these organelles, in agreement with the concept that transient fusion events occur between endosomes and phagosomes. Biochemical analysis showed variations in the levels of rab proteins associated with phagosomes during maturation while other 'fusion' proteins, including synaptobrevin1 and synaptobrevin2, remained constant.

REM sleep behavior disorders in multiple system atrophy.

We report the results of clinical and polysomnographic investigations on 39 consecutive multiple system atrophy (MSA) patients. Twenty-seven patients (69%) reported nocturnal motor paroxysmal episodes related to dreams, suggesting the clinical diagnosis of REM sleep behavior disorder (RBD). In 12 of them (44%), RBD preceded the clinical onset of the disease by more than 1 year. In seven (26%), the RBD onset was concomitant with and in eight (30%) was at least 2 years after the appearance of motor or autonomic symptoms. On polysomnographic recordings, 35 of 39 MSA patients (90%) had RBD. Other polysomnographic findings included nonclinical obstructive sleep apnea in 6 patients, laryngeal stridor in 8 patients, and periodic limb movements during sleep in 10 patients. Our data show that RBD represents the most common clinical sleep manifestation and polysomnographic finding in patients with MSA. RBD can frequently herald the appearance of other MSA symptoms by years. Extended polysomnographic montages are recommended in MSA sleep studies.

Harmonically mode-locked Ti:Er:LiNbO(3) waveguide laser.

Active mode locking of an Er-diffusion-doped Ti:LiNbO(3) waveguide laser by intracavity phase modulation to as high as the fourth harmonic (5.12 GHz) of the axial-mode frequency spacing is reported. The diode-pumped, pigtailed, and fully packaged laser with a monolithically integrated intracavity phase modulator has a threshold of 9 mW (incident pump power E(p) || c) and emits transform-limited pulses of >/=3.8-ps width and