Advanced search    

Search: authors:"Thomas Barclay"

13 papers found.
Use AND, OR, NOT, +word, -word, "long phrase", (parentheses) to fine-tune your search.

Inulin - a versatile polysaccharide with multiple pharmaceutical and food chemical uses

alpha-D-glucopyranosyl-[beta-D-fructofuranosyl](n-1)-D-fructofuranoside, commonly referred to as inulin, is a natural plant-derived polysaccharide with a diverse range of food and pharmaceutical applications. It is used by the food industry as a soluble dietary fibre and fat or sugar replacement, and in the pharmaceutical industry as a stabiliser and excipient. It can also be...

The chemistry and sources of fructose and their effect on its utility and health implications

Fructose is a significant component in unprocessed food and has become one of the most commonly sweeteners used in food manufacturing. Fructose is also a useful pharmaceutical excipient and derivatives of fructose are exploited as renewable chemical building blocks. Fructose based polysaccharides have extensive pharmaceutical and dietary functions. We discuss here the chemistry...

Inulin - a versatile polysaccharide with multiple pharmaceutical and food chemical uses

alpha-D-glucopyranosyl-beta-D-fructofuranosyl-D-fructofuranoside, commonly referred to as inulin, is a natural plant-derived polysaccharide with a diverse range of food and pharmaceutical applications. It is used by the food industry as a soluble dietary fibre and fat or sugar replacement, and in the pharmaceutical industry as a stabiliser and excipient. It can also be used as a...

Suppression of X-rays during an optical outburst of the helium dwarf nova KL Dra

KL Dra is a helium-accreting AM CVn binary system with an orbital period close to 25 min. Approximately every 60 d there is a 4-mag optical outburst lasting ∼10 d. We present the most sensitive X-ray observations made of an AM CVn system during an outburst cycle. A series of eight observations were made using XMM–Newton which started shortly after the onset of an optical outburst...

Serendipitous Kepler observations of a background dwarf nova of SU UMa type

We have discovered a dwarf nova (DN) of type SU UMa in Kepler data which is 7.0 arcsec from the G-type exoplanet survey target KIC 4378554. The DN appears as a background source in the pixel aperture of the foreground G star. We extracted only the pixels where the DN is present and observed the source to undergo five outbursts – one a superoutburst – over a time span of 22 months...

New short-period stellar pulsators at large Galactocentric distances

We report the discovery of 31 blue, short-period, pulsators made using data taken as part of the Rapid Temporal Survey (RATS). We find that they have periods between 51 and 83 min and full amplitudes between 0.05 and 0.65 mag. Using the period–luminosity relationship for short-period pulsating stars, we determine their distance. Assuming that they are pulsating in either the...

2XMMi J225036.9+573154 – a new eclipsing AM Her binary discovered using XMM–Newton

We report the discovery of an eclipsing polar, 2XMMi J225036.9+573154, using XMM–Newton. It was discovered by searching the light curves in the 2XMMi catalogue for objects showing X-ray variability. Its X-ray light curve shows a total eclipse of the white dwarf by the secondary star every 174 min. An extended pre-eclipse absorption dip is observed in soft X-rays at φ= 0.8–0.9...

The long-term optical behaviour of helium-accreting AM CVn binaries

We present the results of a two and a half year optical photometric monitoring programme covering 16 AM CVn binaries using the Liverpool Telescope on La Palma. We detected outbursts in seven systems, one of which (SDSS J0129) was seen in outburst for the first time. Our study coupled with existing data shows that 1/3 of these helium-rich accreting compact binaries show outbursts...

Stellar variability on time-scales of minutes: results from the first 5 yr of the Rapid Temporal Survey*

The Rapid Temporal Survey (RATS) explores the faint, variable sky. Our observations search a parameter space which, until now, has never been exploited from the ground. Our strategy involves observing the sky close to the Galactic plane with wide-field CCD cameras. An exposure is obtained approximately every minute with the total observation of each field lasting around 2 h. In...

Multiwavelength observations of the helium dwarf nova KL Dra through its outburst cycle

We present multiwavelength observations of the helium-dominated accreting binary KL Dra which has an orbital period of 25 min. Our ground-based optical monitoring programme using the Liverpool Telescope has revealed KL Dra to show frequent outbursts. Although our coverage is not uniform, our observations are consistent with the outbursts recurring on a time-scale of ∼60 d...

RAT J1953+1859: a dwarf nova discovered through high amplitude QPOs in quiescence

We report the discovery of an accreting binary, RAT J1953+1859, made during the RApid Temporal Survey (RATS) on the Isaac Newton Telescope. It showed high amplitude (0.3 mag) quasi-periodic oscillations on a time-scale of ∼20 min. Further observations made using the Nordic Optical Telescope showed it to be ∼4 mag brighter than in the discovery images. These photometric...