Biography:

In the past R. Parker has collaborated on articles with C.A. McLaughlin and P.V. Desmond. One of their most recent publications is Moieties of mycobacterial mycolates required for inducing granulomatous reactions. Which was published in journal Cellular Immunology.

More information about R. Parker research including statistics on their citations can be found on their Copernicus Academic profile page.

R. Parker's Articles: (18)

Moieties of mycobacterial mycolates required for inducing granulomatous reactions

AbstractTrehalose dimycolates and monomycolates isolated from a variety of Mycobacteria species as well as synthetic trehalose mycolates and trehalose behenylbehenate produced granulomatous responses in the lungs of mice. Trehalose alone or mycolic acids or their methyl esters, however, did not. These data suggest that the sugar moiety of these defined fatty acid esters is required for the production of this cellular inflammatory reaction. When mice were challenged with virulent Mycobactorium tuberculosis they showed increased resistance against infection during the time when the granulomatous response was greatest.

Resonance effects in wake shedding from parallel plates: Some experimental observations

AbstractA series of tests with air flowing over a cascade of flat parallel plates has shown that pressure fluctuations occur with amplitudes of the same order of magnitude as the air stream dynamic head. The fluctuations form a sequence of resonances and are excited by wake shedding from the plate trailing edges.The resonances are caused almost entirely by acoustic effects and have little or no relation to the mechanical vibration of the plates.

Low frequency resonance effects in wake shedding from parallel plates

AbstractAn experimental investigation was made of resonances excited by the wakes shed from cascades of flat plates mounted between side walls in a low-speed wind tunnel. Attention was concentrated on the lower frequencies at which the nodal spacings were greater than the plate spacing. The resonances occur in sequences where the lowest frequency of each sequence corresponds to wave propagation at a velocity close to the velocity of sound and the velocity of propagation falls progressively as the wavelength decreases. The sequence ends with the mode where there is a node in the plane of each plate. Amplitudes as high as 145 dB (re: 00002 dyne/cm2) were recorded in several cases with relative air velocities less than 100 ft/sec.

Acoustic resonances in passages containing banks of heat exchanger tubes

AbstractIt is shown experimentally that the presence of the tubes in a heat exchanger reduces the effective speed of sound in planes normal to the axes of the tubes. The effective speeds are used to analyse the possible resonant acoustic modes of a rectangular duct containing a tube bank filling a section in the centre of the duct. Experimental results confirm the modes and the predicted frequencies.

An experimental investigation of the generation and consequences of acoustic waves in an axial flow compressor: Large axial spacings between blade rows

AbstractThe excitation of acoustic modes in the annulus of a single stage, low speed, axial flow compressor was investigated experimentally. The modes were excited by vortex shedding from the inlet guide vanes and each mode was found to be associated with a number of rotor blade vibration excitation frequencies.

Effect of Cimetidine and other antihistaminics on the elimination of aminopyrine, phenacetin and caffein

AbstractCimetidine is widely prescribed for the treatment of peptic ulcer disease and has recently been shown to inhibit the metabolism of warfarin, antipyrine and diazepam. To further examine this phenomenon we investigated the effect of various doses of cimetidine and other related drugs on 14C-aminopyrine, 14C-phenacetin and 14C-caffeine breath tests. Cimetidine caused a dose-related inhibition of the metabolism of aminopyrine and caffeine but had no effect on the phenacetin breath test. Metiamide, H1-antihistamines, phenothiazines and local anesthetics also inhibited the aminopyrine breath test. Cyproheptadine had no effect on either phenacetin or caffeine elimination. This study demonstrates a complex drug-drug interaction which may have widespread clinical implications.

ReportA survey of shoreline litter in Halifax Harbour 1989☆

AbstractThe problem of marine litter has gained increased public attention over the past decade and has spawned numerous efforts to deal with it. This study provided the first assessment of the type and probable sources of persistent marine litter in Halifax Harbour. The study determined that 62% of the total litter in the harbour originated from recreation and land-based sources. It was concluded that a cooperative effort involving a successful education programme and treatment of the sewage discharged into the harbour could reduce the total amount of marine litter by 82%.

The formation of nickel ferrite

AbstractThe preparation of nickel ferrite in the solid state reaction NiO + Fe2O3 → Ni Fe2O4 is preceeded by the formation of an intermediate oxygen deficient material. Although X-ray powder photographs have not revealed a separate phase, neither the magnetic properties nor the oxygen affinity of the material corresponds to that of the initial materials or the finial product.

Vortex shedding from flat plates under the influence of an acoustic field

AbstractExperimental data obtained with two flat plates in tandem in a wind tunnel are presented. Attention is concentrated on the phase of the vortex shedding from the upstream plate relative to the acoustic field when a resonance is excited. At some plate spacings a resonance was excited over two ranges of flow velocity, at the lower velocities the relationship between phase and velocity was found to be similar to that with a single plate but, at the higher velocities, it was quite different. The implications regarding resonances in axial-flow compressors are discussed.

Positron Emission Tomography — A New Technique for Observing Fluid Behaviour in Engineering Systems

ABSTRACTEngineers often need to know the flow patterns of fluids within their machinery. Positron emission tomography promises to become a powerful new technique for flow tracing and measurement within metal structures in general and operating engines in particular. The principles involved are outlined, and a mobile positron camera system being developed jointly by Rolls-Royce, Castrol, the University of Birmingham and the Rutherford-Appleton Laboratory of the SERC is described. Finally, illustrative examples of the camera's capability are presented drawn from its use to study lubricating fluid flow in the bearings of a Viper gas turbine engine on test up to 100% full power.

On the use of fast fourier transforms when high frequency resolution is required

The paper gives a method of obtaining high frequency resolution of spectral peaks when time series data is transformed to the frequency domain by means of a simple Fast Fourier Transform.

ReviewChandrayaan-1 X-ray Spectrometer (C1XS)—Instrument design and technical details

AbstractThe UK-built Chandrayaan-1 X-ray Spectrometer (C1XS) is flying as an ESA instrument on India's Chandrayaan-1 mission to the Moon. The Chandrayaan-1 mission launched on the 22nd October 2008 and entered a 100 km polar lunar orbit on the 12th November 2008. C1XS builds on experience gained with the earlier D-CIXS instrument on SMART-1, but will be a technically much more capable instrument. Here we describe the instrument design.

Global satellite observations of column-averaged carbon dioxide and methane: The GHG-CCI XCO2 and XCH4 CRDP3 data set

Highlights•State-of-the-art satellite-derived data sets of atmospheric CO2 and CH4•Comparisons with TCCON ground-based observations•Critical GCOS requirements are met (with some exceptions).•Detailed comparisons with state-of-the art global CO2 assimilation systems•Overall, reasonable agreement between all CO2 data sets

Mycobacteria and allograft heart valve banking: an international survey

SummarySince the 1970s many tissue banks have been testing allograft heart valves (HVs) for Mycobacterium tuberculosis (MTB). Donor selection for low risk of tuberculosis (TB) was introduced in the 1980s and appears to have reduced the risk of TB transmission. Regulatory guidance does not specify testing for TB, but does exclude donors with a recent history of TB. This survey of HV international bank practices revealed variations in donor selection, testing and processing of valves. Participant banks (from Europe and the USA) reported that over a period of 15 years, HV tissues from 38 413 donors were banked and 32 289 donors were tested for TB, none being positive. HV-associated tissue from 27 840 donors was stained and underwent microscopy; none of these were positive for acid-fast bacilli (AFB). Non-tuberculosis mycobacteria (NTBM) were detected by culture on 24 HVs. It is recommended that HV banks employ donor selection to exclude donors at risk of TB, to culture material for mycobacteria, and to investigate potential sources when clusters of NTBM are found to facilitate corrective and preventative actions.

The Alcator C-Mod lower hybrid current drive experiment transmitter

AbstractAlcator C-Mod, is a high-field high-density, diverted, compact tokamak, which, in its present form uses inductive current drive and is heated with 5 MW of ICRF auxiliary power. C-Mod is in the process of being upgraded with a 4.6 GHz lower hybrid heating and current drive (LHCD) system. The purpose of the experiment is to develop and explore the potential of “Advanced Tokamak Regimes” under quasi-steady-state conditions. In this paper, an overview of the RF transmitter and the controls and protection systems for the Lower Hybrid Project is given. The transmitter will use 12 250 kW klystrons operating simultaneously which will result in a total nominal power at the klystrons of nearly 3 MW for a planned pulse width of 5 s. Active control system vector modulators provide phase and amplitude drive for each klystron, and I-Q detectors are used to monitor phase and amplitude. These feedback signals are used in digital controllers for closed-loop control of klystron phase and amplitude to preset values. An expected upgrade of four additional klystrons will result in a total nominal power of 4 MW. The transmitters have been tested to full power, and installation of the lower hybrid current drive experiment on the C-Mod Tokamak is expected in 2004/2005.

ITER breeding blanket design for the enhanced performance phase

AbstractThe International Thermonuclear Experimental Reactor (ITER) breeding blanket is designed to breed the necessary tritium for ITER operation during the enhanced performance phase by replacing the shielding blanket of the basic performance phase. Similar to the shielding blanket, it has to remove the majority of the fusion power generated by the plasma and to protect the vacuum vessel and the toroidal field coils from excessive nuclear heating and radiation damage. It has to produce a net tritium breeding ratio of more than 0.8 to satisfy the technical objectives of the enhanced performance phase. For compatibility with the ITER design and to satisfy the blanket functional requirements, a water-cooled modular solid breeder blanket with a beryllium neutron multiplier has been selected. Lithium zirconate is the reference breeder material based on the current database. Enriched lithium is used to enhance the tritium breeding capability, to reduce the radial blanket thickness, to decrease the breeder material volume, to lower the breeder thermal stresses, and to enhance the shielding capability. Similar to the shielding blanket, the breeding blanket uses Type 316LN-IG austenitic steel structural material. Both forms of beryllium material, porous and pebbles, are used at different blanket locations based on design requirements. This paper is concerned with the design analyses and design selections, including beryllium form, breeder material, tritium breeding, and heat transfer across the beryllium–steel interface. Also, the required research and development tasks for the ITER breeding blanket are summarized.

Chapter IX Neuropeptide Y, peptide YY and pancreatic polypeptide receptor proteins and mRNAs in mammalian brains

Publisher SummaryStudies in rodents and primates suggest that neuropeptide Y (NPY) and peptide YY (PYY), as well as their receptors could have a direct implication in some pathological disorders including obesity, depression and epilepsy. Obesity is one of the major health issues in industrialized countries and most recent studies suggest that NPY could be one of the key peptides in feeding behavior. It is thus not surprising that this peptide has generated much interest in pharmaceutical and academic laboratories. This chapter reviews the distribution and biological effects of NPY and related peptides in the brain, focusing on the characterization and distribution of the NPY Y1, Y2, Y4 and Y5 receptor protein and their mRNA in the rat brain. Additionally, the chapter presents a comparative distribution of the various NPY receptor subtypes in other species, including man. The chapter discusses the possible physiological and pathophysiological implications of NPY and its receptors.

Research paperThe aggregative stability of β-lactoglobulin in glassy mixtures with sucrose, trehalose and dextran

AbstractThe aim of this study was to investigate the effect of the addition of different carbohydrates on the thermally induced aggregation of a model globular protein, β-lactoglobulin (BLG), in the glass state. Amorphous mixtures of BLG with trehalose, sucrose and dextran were prepared by freeze-drying, their glass behaviour was characterised using calorimetry and thermally induced aggregation was measured using size exclusion chromatography. Pure BLG shows increasing levels of aggregation when heated in the temperature range 70–100 °C for 48–144 h. The addition of the disaccharides sucrose and trehalose both resulted in a decrease in aggregation rate which approached negligible rates at 50 wt.% carbohydrate. The effect of dextran addition was similar to that of the disaccharides when preparations containing 9 wt.% carbohydrate were heated at 70 °C for 2 days. However, when the concentration exceeded 23 wt.%, the reaction temperature was 70 °C or above or the reaction time was longer than 48 h, the addition of the polysaccharide did not protect the protein from thermally induced aggregation, suggesting that protein–polymer phase separation could have occurred during freeze-drying. Overall the results support the proposal that one aspect of carbohydrate additive functionality is as a diluent with the added condition that the carbohydrate remains miscible with the protein during processing.

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