Polarisation Patterns and Vectorial Defects in Type II Optical Parametric Oscillators

Previous studies of lasers and nonlinear resonators have revealed that the polarisation degree of freedom allows for the formation of polarisation patterns and novel localized structures, such as vectorial defects. Type II optical parametric oscillators are characterised by the fact that the down-converted beams are emitted in orthogonal polarisations. In this paper we show the results of the study of pattern and defect formation and dynamics in a Type II degenerate optical parametric oscillator for which the pump field is not resonated in the cavity. We find that traveling waves are the predominant solutions and that the defects are vectorial dislocations which appear at the boundaries of the regions where traveling waves of different phase or wave-vector orientation are formed. A dislocation is defined by two topological charges, one associated with the phase and another with the wave-vector orientation. We also show how to stabilize a single defect in a realistic experimental situation. The effects of phase mismatch of nonlinear interaction are finally considered.Comment: 38 pages, including 15 figures, LATeX. Related material, including movies, can be obtained from http://www.imedea.uib.es/Nonlinear/research_topics/OPO

Effect of rehabilitation worker input on visual function outcomes in individuals with low vision: study protocol for a randomised controlled trial

BACKGROUND: Visual Rehabilitation Officers help people with a visual impairment maintain their independence. This intervention adopts a flexible, goal-centred approach, which may include training in mobility, use of optical and non-optical aids, and performance of activities of daily living. Although Visual Rehabilitation Officers are an integral part of the low vision service in the United Kingdom, evidence that they are effective is lacking. The purpose of this exploratory trial is to estimate the impact of a Visual Rehabilitation Officer on self-reported visual function, psychosocial and quality-of-life outcomes in individuals with low vision. METHODS/DESIGN: In this exploratory, assessor-masked, parallel group, randomised controlled trial, participants will be allocated either to receive home visits from a Visual Rehabilitation Officer (n = 30) or to a waiting list control group (n = 30) in a 1:1 ratio. Adult volunteers with a visual impairment, who have been identified as needing rehabilitation officer input by a social worker, will take part. Those with an urgent need for a Visual Rehabilitation Officer or who have a cognitive impairment will be excluded. The primary outcome measure will be self-reported visual function (48-item Veterans Affairs Low Vision Visual Functioning Questionnaire). Secondary outcome measures will include psychological and quality-of-life metrics: the Patient Health Questionnaire (PHQ-9), the Warwick-Edinburgh Mental Well-being Scale (WEMWBS), the Adjustment to Age-related Visual Loss Scale (AVL-12), the Standardised Health-related Quality of Life Questionnaire (EQ-5D) and the UCLA Loneliness Scale. The interviewer collecting the outcomes will be masked to the group allocations. The analysis will be undertaken on a complete case and intention-to-treat basis. Analysis of covariance (ANCOVA) will be applied to follow-up questionnaire scores, with the baseline score as a covariate. DISCUSSION: This trial is expected to provide robust effect size estimates of the intervention effect. The data will be used to design a large-scale randomised controlled trial to evaluate fully the Visual Rehabilitation Officer intervention. A rigorous evaluation of Rehabilitation Officer input is vital to direct a future low vision rehabilitation strategy and to help direct government resources. TRIAL REGISTRATION: The trial was registered with ( ISRCTN44807874 ) on 9 March 2015

Monoaminergic and histaminergic strategies and treatments in brain diseases

The monoaminergic systems are the target of several drugs for the treatment of mood, motor and cognitive disorders as well as neurological conditions. In most cases, advances have occurred through serendipity, except for Parkinson's disease where the pathophysiology led almost immediately to the introduction of dopamine restoring agents. Extensive neuropharmacological studies first showed that the primary target of antipsychotics, antidepressants, and anxiolytic drugs were specific components of the monoaminergic systems. Later, some dramatic side effects associated with older medicines were shown to disappear with new chemical compounds targeting the origin of the therapeutic benefit more specifically. The increased knowledge regarding the function and interaction of the monoaminergic systems in the brain resulting from in vivo neurochemical and neurophysiological studies indicated new monoaminergic targets that could achieve the efficacy of the older medicines with fewer side-effects. Yet, this accumulated knowledge regarding monoamines did not produce valuable strategies for diseases where no monoaminergic drug has been shown to be effective. Here, we emphasize the new therapeutic and monoaminergic-based strategies for the treatment of psychiatric diseases. We will consider three main groups of diseases, based on the evidence of monoamines involvement (schizophrenia, depression, obesity), the identification of monoamines in the diseases processes (Parkinson's disease, addiction) and the prospect of the involvement of monoaminergic mechanisms (epilepsy, Alzheimer's disease, stroke). In most cases, the clinically available monoaminergic drugs induce widespread modifications of amine tone or excitability through neurobiological networks and exemplify the overlap between therapeutic approaches to psychiatric and neurological conditions. More recent developments that have resulted in improved drug specificity and responses will be discussed in this review.peer-reviewe

CRISPR-Cas13d Induces Efficient mRNA Knockdown in Animal Embryos

Early embryonic development is driven exclusively by maternal gene products deposited into the oocyte. Although critical in establishing early developmental programs, maternal gene functions have remained elusive due to a paucity of techniques for their systematic disruption and assessment. CRISPR-Cas13 systems have recently been employed to degrade RNA in yeast, plants, and mammalian cell lines. However, no systematic study of the potential of Cas13 has been carried out in an animal system. Here, we show that CRISPR-RfxCas13d (CasRx) is an effective and precise system to deplete specific mRNA transcripts in zebrafish embryos. We demonstrate that zygotically expressed and maternally provided transcripts are efficiently targeted, resulting in a 76% average decrease in transcript levels and recapitulation of well-known embryonic phenotypes. Moreover, we show that this system can be used in medaka, killifish, and mouse embryos. Altogether, our results demonstrate that CRISPR-RfxCas13d is an efficient knockdown platform to interrogate gene function in animal embryos.This work was supported by Ramon y Cajal program (RyC-2017-23041) and grants PGC2018-097260-B-I00 and MDM-2016-0687 from Spanish Ministerio de Ciencia, Innovación y Universidades and the Springboard program from CABD (M.A.M.-M.) and the Stowers Institute for Medical Research (A.A.B.). M.A.M.-M. was the recipient of the Genome Engineer Innovation 2019 Grant from Synthego. A.A.B. was awarded with Pew Innovation Fund. J.R.M.-M. is supported by BFU2017-86339-P and MDM-2016-0687 grants (Spanish Ministerio de Ciencia, Innovación y Universidades). E.M.-T. and J.A.-N.d.P. are supported by INNOVATE PERÚ grant 168-PNICP-PIAP-2015 and FONDECYT travel grant 043-2019

Aspekty środowiskowego bezpieczeństwa wykorzystania systemów UHF RFID w szpitalach

Various applications of Radio Frequency IDentification (RFID) technology in the medical environment are characterised. The electromagnetic field (EMF) emitted by RFID handheld readers (RFID guns) is characterised and evaluated with respect to humans exposure metrics – the strength of the electric field affecting anyone present near various UHF (ultra-high frequency) RFID guns and the specific absorption rate (SAR) values in their body. UHF RFID systems are the most popular of such systems used in hospitals. The performed studies indicate that the EMF exposure level near the RFID gun antenna and SAR values (a measure of the thermal effects of EMF exposure) caused by exposure from the RFID reader may exceed the limits of the electric field and SAR issued by international guidelines or legislation. Potentially excessive exposure to EMF emitted by UHF RFID readers is not limited to the user of the device, but may also apply to patients or bystanders. Only UHF RFID guns with an EMF emission lower than 1 W may be considered as an insignificant source of human exposure. The use of readers with a radiated power exceeding 1 W requires the evaluation of the EMF level using measurements, and also the evaluation of SAR by numerical modelling in the case of their use in close proximity to humans. In all cases, insufficient electromagnetic immunity of electronic devices (including medical implants) should be considered near RFID guns at least up to half of the reading range away from the RFID reader. The electromagnetic hazards related to the use of RFID guns may be limited by relevant preventive measures, as shown in this paper, together with the principles of an in-situ evaluation of electromagnetic hazards near the UHF RFID guns.Scharakteryzowano różne zastosowania technologii identyfikacji radiowej (RFID) w środowisku medycznym. Pole elektromagnetyczne emitowane przez ręczne czytniki RFID (RFID guns) zostało scharakteryzowane i ocenione w odniesieniu do miar narażenia ludzi – natężenia pola elektrycznego oddziałującego na osoby znajdujące się w pobliżu różnych czytników RFID UHF (ultrawysokiej częstotliwości) i współczynnika SAR w ich ciele. System UHF RFID jest najpopularniejszym z systemów RFID użytkowanych m.in. w szpitalach. Przeprowadzone badania wskazują, że poziom ekspozycji na pole elektromagnetyczne w pobliżu anteny ręcznego czytnika RFID i wartości SAR (miara skutków termicznych oddziaływania pola elektromagnetycznego) spowodowane tą ekspozycją mogą przekraczać limity, opublikowane w zleceniach międzynarodowych lub przepisach. Nadmierna ekspozycja na pole elektromagnetyczne emitowane przez czytniki RFID UHF może dotyczyć nie tylko użytkownika urządzenia, ale również pacjenta lub osoby postronnej. Tylko ręczne czytniki RFID UHF o emisji pola elektromagnetycznego poniżej 1 W można uznać za nieistotne źródło narażenia ludzi. Korzystanie z czytników o mocy przekraczającej 1 W wymaga oceny poziomu pola elektromagnetycznego za pomocą pomiarów, a również oceny SAR za pomocą modelowania numerycznego w przypadku ich użycia w bezpośredniej bliskości ludzi. We wszystkich przypadkach niewystarczającą odporność elektromagnetyczną urządzeń elektronicznych (w tym implantów medycznych) należy rozważyć w pobliżu czytników RFID co najmniej do odległości od czytnika RFID równej połowie jego zasięgu odczytu. Zagrożenia elektromagnetyczne związane z używaniem ręcznych czytników RFID mogą być ograniczone przez odpowiednie środki ochronne, jak pokazano w tym artykule, wraz z zasadami oceny zagrożeń elektromagnetycznych in-situ w pobliżu ręcznych czytników UHF RFID