Second Data Release from the European Pulsar Timing Array: Challenging the Ultralight Dark Matter Paradigm.

Pulsar Timing Array experiments probe the presence of possible scalar or pseudoscalar ultralight dark matter particles through decade-long timing of an ensemble of galactic millisecond radio pulsars. With the second data release of the European Pulsar Timing Array, we focus on the most robust scenario, in which dark matter interacts only gravitationally with ordinary baryonic matter. Our results show that ultralight particles with masses 10^{-24.0} eV≲m≲10^{-23.3} eV cannot constitute 100% of the measured local dark matter density, but can have at most local density ρ≲0.3 GeV/cm^{3}.

A strong magnetic field around the supermassive black hole at the centre of the Galaxy.

Earth's nearest candidate supermassive black hole lies at the centre of the Milky Way. Its electromagnetic emission is thought to be powered by radiatively inefficient accretion of gas from its environment, which is a standard mode of energy supply for most galactic nuclei. X-ray measurements have already resolved a tenuous hot gas component from which the black hole can be fed. The magnetization of the gas, however, which is a crucial parameter determining the structure of the accretion flow, remains unknown. Strong magnetic fields can influence the dynamics of accretion, remove angular momentum from the infalling gas, expel matter through relativistic jets and lead to synchrotron emission such as that previously observed. Here we report multi-frequency radio measurements of a newly discovered pulsar close to the Galactic Centre and show that the pulsar's unusually large Faraday rotation (the rotation of the plane of polarization of the emission in the presence of an external magnetic field) indicates that there is a dynamically important magnetic field near the black hole. If this field is accreted down to the event horizon it provides enough magnetic flux to explain the observed emission--from radio to X-ray wavelengths--from the black hole.

Establishment of a clinical network for children with amelogenesis imperfecta and dentinogenesis imperfecta in the UK: 4-year experience.

BACKGROUND: Amelogenesis imperfecta (AI) and dentinogenesis imperfecta (DI) are two groups of genetically inherited conditions resulting in abnormal enamel and dentin formation, respectively. Children and young people may be adversely affected by these conditions, with significant reduction in oral health related quality of life. Dental management of children with AI and DI is often complex, which is exacerbated by the absence of clear referral pathways and scarce evidence-based guidelines. METHOD: The need for increased knowledge and peer support led to the development of a group of UK paediatric dentists with a special clinical interest in the management of children with AI and DI. PURPOSE: The aims of this paper are to describe the establishment of an AI/DI Clinical Excellence Network (AI/DI CEN) in paediatric dentistry including outputs and future plans, and to share our collective learning to help support others anywhere in the world advance the care of people with AI or DI.

Neutron star mass estimates from gamma-ray eclipses in spider millisecond pulsar binaries.

Reliable neutron star mass measurements are key to determining the equation of state of cold nuclear matter, but such measurements are rare. Black widows and redbacks are compact binaries consisting of millisecond pulsars and semi-degenerate companion stars. Spectroscopy of the optically bright companions can determine their radial velocities, providing inclination-dependent pulsar mass estimates. Although inclinations can be inferred from subtle features in optical light curves, such estimates may be systematically biased due to incomplete heating models and poorly understood variability. Using data from the Fermi Large Area Telescope, we have searched for gamma-ray eclipses from 49 spider systems, discovering significant eclipses in 7 systems, including the prototypical black widow PSR B1957+20. Gamma-ray eclipses require direct occultation of the pulsar by the companion, and so the detection, or significant exclusion, of a gamma-ray eclipse strictly limits the binary inclination angle, providing new robust, model-independent pulsar mass constraints. For PSR B1957+20, the eclipse implies a much lighter pulsar (1.81 ± 0.07 solar masses) than inferred from optical light curve modelling.

Transient radio bursts from rotating neutron stars.

The radio sky is relatively unexplored for transient signals, although the potential of radio-transient searches is high. This was demonstrated recently by the discovery of a previously unknown type of source, varying on timescales of minutes to hours. Here we report a search for radio sources that vary on much shorter timescales. We found eleven objects characterized by single, dispersed bursts having durations between 2 and 30 ms. The average time intervals between bursts range from 4 min to 3 h with radio emission typically detectable for <1 s per day. From an analysis of the burst arrival times, we have identified periodicities in the range 0.4-7 s for ten of the eleven sources, suggesting origins in rotating neutron stars. Despite the small number of sources detected at present, their ephemeral nature implies a total Galactic population significantly exceeding that of the regularly pulsing radio pulsars. Five of the ten sources have periods >4 s, and the rate of change of the pulse period has been measured for three of them; for one source, we have inferred a high magnetic field strength of 5 x 10(13) G. This suggests that the new population is related to other classes of isolated neutron stars observed at X-ray and gamma-ray wavelengths.

Patient-reported outcome measures for children and adolescents having dental bleaching in the UK.

PURPOSE: Dental bleaching in paediatric patients can be used to address discolouration of teeth due to trauma, endodontic treatment, or enamel and dentine defects. Despite being a minimally invasive and successful treatment, the use of bleaching products in children and young people remains controversial. This evaluation was designed to provide insight into the child's perspective on dental bleaching and the influence that this treatment has upon their life. METHOD: A dental bleaching patient reported outcome measure (PROM) was developed and piloted in 2019. Data were collected from 3 UK units (January-March 2020). Children attending these units for bleaching reviews were invited to complete the PROM. RESULTS: Twenty seven PROM questionnaires were completed including 19 courses of external bleaching and 8 courses of internal/external bleaching. The average age was 14 years old (9-17 years). The common indications for bleaching were Amelogenesis Imperfecta, dental trauma and Molar Incisor Hypomineralisation. Patients reported improvements in their appearance (89%) and self-confidence (81%). Sensitivity was the most common side effect, reported in 63% of cases. CONCLUSION: This PROM supports the use of dental bleaching in children and young people when treating dental disease that causes discolouration. Bleaching not only improved the appearance of teeth, but also patients' self-confidence. Sensitivity is a common side effect and clinicians should discuss this common risk and its management with patients and their families.

Non-sterile examination gloves and sterile surgical gloves: which are more sustainable?

BACKGROUND: Healthcare professionals should consider environmental sustainability when using personal protective equipment (PPE). One of the most frequently used items of PPE in medical settings are gloves. AIM: This study aims to quantify the environmental impact of sterile versus non-sterile gloves using the life cycle assessment (LCA) methodology. METHODS: This study used three glove types: non-sterile gloves and sterile gloves (latex and latex-free). Sixteen different environmental impact categories were used to demonstrate the impact of each glove type. FINDINGS: Non-sterile gloves had the least environmental impact in all categories. The two types of sterile gloves, non-latex (synthetic rubber) and latex (natural rubber), performed similarly, although the non-latex gloves had a greater impact on ozone depletion, mineral use and ionizing radiation. For climate change impact, sterile latex gloves were 11.6 times higher than non-sterile gloves. This study found that for both sterile type gloves (latex and non-latex), the manufacture of the gloves contributes to the most considerable environmental impact, with an average of 64.37% for sterile latex gloves and 60.48% for non-latex sterile gloves. CONCLUSION: Using the LCA methodology, this study quantitatively demonstrated the environmental impact of sterile versus non-sterile gloves.

An increased estimate of the merger rate of double neutron stars from observations of a highly relativistic system.

The merger of close binary systems containing two neutron stars should produce a burst of gravitational waves, as predicted by the theory of general relativity. A reliable estimate of the double-neutron-star merger rate in the Galaxy is crucial in order to predict whether current gravity wave detectors will be successful in detecting such bursts. Present estimates of this rate are rather low, because we know of only a few double-neutron-star binaries with merger times less than the age of the Universe. Here we report the discovery of a 22-ms pulsar, PSR J0737-3039, which is a member of a highly relativistic double-neutron-star binary with an orbital period of 2.4 hours. This system will merge in about 85 Myr, a time much shorter than for any other known neutron-star binary. Together with the relatively low radio luminosity of PSR J0737-3039, this timescale implies an order-of-magnitude increase in the predicted merger rate for double-neutron-star systems in our Galaxy (and in the rest of the Universe).

Reaction times of children having nitrous oxide inhalation sedation for dental procedures.

BACKGROUND: Inhalation sedation (IHS), using nitrous oxide and oxygen, is a commonly used form of pharmacological behaviour management in paediatric dentistry. Previous studies suggest that IHS causes a delay in reaction time, which recovers to baseline within 10 min. AIM: To observe the reaction times (RT) of children before and after undergoing IHS for dental treatment. DESIGN: Sixty children from clinics at St Thomas' Hospital (London, UK) participated in this observational study. RT was measured using an eight-point choice reaction time system (MOART computer panel, Lafayette Instruments). RT was measured twice: before (prior to patient entering clinic for treatment) and after (immediately after discharge from the clinic). A paired-samples t test was used to analyse data. RESULTS: Fifty-two patients completed the study. There was a statistically significant delay in RT after treatment (p = 0.022). There was no significant correlation between RT and concentration of nitrous oxide, or length of the recovery period. CONCLUSION: Children may have a small impairment in reaction times following recovery from IHS in the clinical setting, regardless of the strength of nitrous oxide given, or the length of the recovery period. The child's escort should be aware of the need to supervise the child following discharge.

The orthodontic-oral surgery interface. Part two: diagnosis and management of anomalies in eruption and transpositions.

The orthodontic-oral surgery interface is important for the multidisciplinary management of patients presenting with complex dental anomalies. This article provides an overview of anomalies of eruption and transpositions, their diagnosis, aetiology, presenting features and the different management options. It also highlights the role of the general dental practitioner (GDP) in identifying such anomalies and the importance of timely referral to specialist care.

MMX Multi Matrix System mesalazine for the induction of remission in patients with mild-to-moderate ulcerative colitis: a combined analysis of two randomized, double-blind, placebo-controlled trials.

BACKGROUND: MMX mesalazine [LIALDA (US), MEZAVANT XL (UK and Ireland) MEZAVANT (elsewhere)] utilizes MMX Multi Matrix System (MMX) technology which delivers mesalazine throughout the colon. Two phase III studies have already evaluated MMX mesalazine in patients with active, mild-to-moderate ulcerative colitis. Aim To provide more precise estimates of the efficacy of MMX mesalazine over placebo by combining the patient populations from the two phase III studies. Methods Combined data from two 8-week, double-blind, placebo-controlled trials were analyzed. Patients randomized to MMX mesalazine 2.4 g/day (once daily or 1.2 g twice daily), 4.8 g/day (once daily) or placebo were reviewed. The primary end point was clinical and endoscopic remission (modified Ulcerative Colitis-Disease Activity Index of /=1-point reduction in sigmoidoscopy score from week 0). Results Data from 517 patients were analysed. 8-week remission rates were 37.2% and 35.1% in the MMX mesalazine 2.4 g/day and 4.8 g/day groups, vs. 17.5% on placebo (P < 0.001, both comparisons). 8-week complete mucosal healing rates were 32% in both MMX mesalazine groups compared with 16% on placebo. Adverse event frequency was similar in all groups. Conclusion MMX mesalazine is effective and generally well tolerated for inducing clinical and endoscopic remission of active, mild-to-moderate ulcerative colitis.

Corneal sensation in scleritis and episcleritis.

A series of 59 patients were examined for loss of corneal sensitivity. Thirty-five of them suffered from scleritis and 24 suffered from episcleritis. There was a difference between the 2 conditions in that significantly more patients with scleritis were affected than patients with episcleritis. It was also found that among the scleritis patients there was a close relationship between the number of quadrants affected and decrease in sensitivity. Five patients had necrotising scleritis, and they all showed marked loss of sensitivity. Sensitivity returned to normal when the scleritis resolved except when a large area of scleral ectasia resulted. The test is of importance because it is one of the easiest methods of detecting the onset of necrotising scleritis in its earliest stages.

A disposable cannula for the aspiration of soft lens matter.

A double cannula is described suitable for the aspiration of soft lens matter. The cannula is a modification of a double irrigation needle already marketed and will be available in a presterilised disposable pack for use with disposable syringes.

EMSA: a SAAM service for the estimation of population parameters based on model fits to identically replicated experiments.

This paper presents a new technique for the aggregation of models to produce population parameter estimates based on a set of identically replicated experiments. After describing the theoretical basis for the technique we discuss tactical and strategic issues associated with its implementation in the SAAM software. Finally, we demonstrate its utility in the aggregation of models fitted to four simulated experiments.

Transformation of a star into a planet in a millisecond pulsar binary.

Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitary, and their origin is therefore mysterious. PSR J1719-1438, a 5.7-millisecond pulsar, was detected in a recent survey with the Parkes 64-meter radio telescope. We show that this pulsar is in a binary system with an orbital period of 2.2 hours. The mass of its companion is near that of Jupiter, but its minimum density of 23 grams per cubic centimeter suggests that it may be an ultralow-mass carbon white dwarf. This system may thus have once been an ultracompact low-mass x-ray binary, where the companion narrowly avoided complete destruction.

Pulsar discovery by global volunteer computing.

Einstein@Home aggregates the computer power of hundreds of thousands of volunteers from 192 countries to mine large data sets. It has now found a 40.8-hertz isolated pulsar in radio survey data from the Arecibo Observatory taken in February 2007. Additional timing observations indicate that this pulsar is likely a disrupted recycled pulsar. PSR J2007+2722's pulse profile is remarkably wide with emission over almost the entire spin period; the pulsar likely has closely aligned magnetic and spin axes. The massive computing power provided by volunteers should enable many more such discoveries.