P. J. Roberts

Publication List Details

Period

1980 - 2009

Number

106

Co-Authors

Light and gas confinement in hollow-core photonic crystal fibre based photonic microcells (2009)

Benabid, F, Roberts, P J, Couny, Francois, Light, Philip S

We review the recent progress on the understanding of optical guidance mechanisms in hollow-core photonic crystal fibres, and on the quantum and nonlinear optical applications of photonic microcells...

Double photonic bandgap hollow-core photonic crystal fiber (2009)

Light, P.S, Couny, F., Wang, Yingying, Wheeler, N.V, Roberts, P.J., Benabid, F.

We report on the design, fabrication and characterization of hollow-core photonic crystal fiber with two robust bandgaps that bridge the benchmark laser wavelengths of 1064nm and 1550nm. The...

Fourth-order dispersion mediated solitonic radiations in HC-PCF cladding (2008)

Benabid, F, Biancalana, E., Light, P. S., Couny, Francois, Luiten, A., Roberts, P. J., ...

We observe experimentally, for the first time to our knowledge, the simultaneous emission of two strong conjugate resonant dispersive waves by optical solitons. The effect is observed in a small...

Fourth-order dispersion mediated solitonic radiations in HC-PCF cladding (2008)

Benabid, F, Biancalana, F., Light, P. S., Couny, Francois, Luiten, A., Roberts, P. J., ...

We observe experimentally, for the first time to our knowledge, the simultaneous emission of two strong conjugate resonant dispersive waves by optical solitons. The effect is observed in a small...

Large Pitch Hollow Core Honeycomb Fiber (2008)

Beaudou, B., Couny, Francois, Benabid, F, Roberts, P. J.

A new kind of hollow core photonic crystal fiber (HC-PCF) for broadband guidance is introduced. Structural and optical properties of a fabricated example are detailed.

Generation of Multi-Octave Optical-Frequency Combs in a Kagome Lattice Hollow Core Photonic Crystal Fiber (2008)

Couny, Francois, Benabid, F, Roberts, P. J., Light, P. S., Raymer, M. G.

A 3-octave spectral comb is generated in a hydrogen-filled hollow-core photonic-crystal-fiber. The spectrum consists of up to 45 high-order Stokes and anti-Stokes lines generated by coherent...

Square-Lattice Large-Pitch Hollow-Core Photonic Crystal Fiber (2008)

Couny, Francois, Roberts, P. J., Benabid, F, Birks, T. A.

Large pitch square-lattice hollow core photonic crystal fibers have been fabricated. Measurements show that the fiber exhibits similar optical linear properties to the Kagome fiber.

Observation of anti-crossing events via mode-pattern rotation in HC-PCF (2008)

Light, P. S., Roberts, P. J., Mirault, P., Benabid, F

We observe the effects of anti-crossing events between core and core interface guided modes of a HC-PCF, by monitoring the output of the fiber as the coupled laser is scanned in wavelength.

Efficient optimization of hollow-core photonic crystal fiber design using the finite-element method (2006)

R. Holzlohner; European Southern Observatory (ESO), S. Burger; Zuse Institute Berlin (ZIB), P. J. Roberts; Department Of Communications, Optics And Materials, TU Of Denmark

We employ a finite-element (FE) solver with adaptive grid refinement to model hollow-core photonic crystal fibers (HC-PCFs) whose core is formed from 19 omitted cladding unit cells. We optimize the...

Achieving low loss and low nonlinearity in hollow core photonic crystal fibers (2005)

Roberts, P. J., Couny, F., Birks, T. A., Knight, J. C., St Russell, P. J., Mangan, B. J., ...

Loss and nonlinearity in hollow core photonic crystal fibers are shown to be simultaneously reduced by the incorporation of anti-resonant features within the boundary region between the core and the...

The fundamental limits to the attenuation of hollow-core photonic crystal fibres (2005)

Birks, T. A., Roberts, P. J., Couny, F., Sabert, H., Mangan, B. J., Williams, D. P., ...

We propose that the transmission of hollow-core photonic crystal fibres is ultimately limited by scattering from roughness due to frozen-in surface capillary waves. This is confirmed by measurements...

A video geo-location and image enhancement tool for small unmanned air vehicles (UAVs) (2004)

Gibbins, Danny, Roberts, P. J., Swierkowski, L.

This paper describes recent work conducted in collaboration with DSTO Australia and Aerosonde to develop video-based geolocation (targeting) and real-time enhancement of ground features observed from...

A video geo-location and image enhancement tool for small unmanned air vehicles (UAVs) (2004)

Gibbins, Danny, Roberts, P. J., Swierkowski, L.

This paper describes recent work conducted in collaboration with DSTO Australia and Aerosonde to develop video-based geolocation (targeting) and real-time enhancement of ground features observed from...

Low loss (1.7 dB/km) hollow core photonic bandgap fiber (2004)

Mangan, B. J., Farr, L., Langford, A., Roberts, P. J., Williams, D. P., Couny, F., ...

We report a silica hollow core photonic bandgap fiber with a minimum attenuation of 1.72 dB/km at 1565 nm wavelength and discuss the scaling of attenuation with wavelength and the minimum loss...

Does the type of flooring affect the risk of hip fracture? (2004)

Lamb, S., Roberts, P. J., Gardner, T. N., Evans, J. Grimley

Background: the number of hip fractures occurring worldwide in 1990 was estimated at 1.7 million and is predicted to rise to 6.3 million by 2050. The vast majority occur as a result of simple falls...

National Patient Dose Measurement Protocols: An Investigation on Behalf of ICRU (1995)

Roberts, P.J.

Countries that measure radiation exposure of patients during diagnostic radiology generally adopt more than one measurement system. The common methods require the measurement of the primary beam air...

The effect of inhibition of leukotriene synthesis on the activity of interleukin-8 and granulocyte-macrophage colony-stimulating factor (1993)

P. J. Roberts, A. R. Pizzey, D. C. Linch

The cytokines interleukin-8 (IL-8) and granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced the extracellular release of arachidonate metabolites from ionophore-stimulated neutrophils...

International Intercomparisons and Accreditation Programmes for Personal Radiation Protection Dosimetry Within the European Community (1992)

Ambrosi, P., Buchholz, G., Marshall, T.O., Roberts, P.J., Thompson, I.M.G.

The numerous intercomparison programmes of personal dosemeters and dosimetry services organised by the Commission of the European Communities (CEC) are described. Recent changes to the CEC Technical...

Radiation Dose in Relation to Compressed Breast Thickness for Screening Mammography (1992)

Whall, M.A., Roberts, P.J.

Quality assurance system guidelines for breast screening mammography have been implemented throughout the UK, in order to minimise the effects of radiation while retaining maximum radiological...

Occupational Exposure in UK Hospitals (1991)

Roberts, P.J., Temperton, D.H.

The Regional Radiation Physics and Protection Service (RRPPS) of the Medical Physics Department at Birmingham monitors the radiation dose of almost 10,000 hospital staff working in the West Midlands...

John Henry ('Halek') Nicholson :--a biography. (1970)

Roberts, P. J.

Thesis (B.A.(Hons.)) - University of Queensland.

Expression of laminin in benign and malignant sclerosing lesions of extrahepatic bile ducts.

Haglund, C, Roberts, P J, Nordling, S

The distribution of laminin, a basement membrane glycoprotein, was studied by an immunohistochemical technique in six samples of benign sclerosing lesions of extrahepatic bile ducts and in 11...

Reported satisfaction among women receiving hormone replacement therapy in a dedicated general practice clinic and in a normal consultation.

Roberts, P J

BACKGROUND. A general practice-based hormone replacement therapy clinic was set up in one practice following the introduction of the 1990 contract for general practitioners. The funding for this...

Hormone replacement therapy: the views of general practitioners and practice nurses.

Roberts, P J, Sibbald, B

The knowledge and attitudes of primary healthcare professionals have been cited as barriers to appropriate uptake of hormone replacement therapy (HRT). This questionnaire survey of general...

The menopause and hormone replacement therapy: views of women in general practice receiving hormone replacement therapy.

Roberts, P J

Women's views on the menopause and hormone replacement therapy were explored using a questionnaire given to women attending one general practice who were having hormone replacement therapy under the...

Expression of laminin in benign and malignant sclerosing lesions of extrahepatic bile ducts.

Haglund, C, Roberts, P J, Nordling, S

The distribution of laminin, a basement membrane glycoprotein, was studied by an immunohistochemical technique in six samples of benign sclerosing lesions of extrahepatic bile ducts and in 11...

Reported satisfaction among women receiving hormone replacement therapy in a dedicated general practice clinic and in a normal consultation.

Roberts, P J

BACKGROUND. A general practice-based hormone replacement therapy clinic was set up in one practice following the introduction of the 1990 contract for general practitioners. The funding for this...

Hormone replacement therapy: the views of general practitioners and practice nurses.

Roberts, P J, Sibbald, B

The knowledge and attitudes of primary healthcare professionals have been cited as barriers to appropriate uptake of hormone replacement therapy (HRT). This questionnaire survey of general...

The menopause and hormone replacement therapy: views of women in general practice receiving hormone replacement therapy.

Roberts, P J

Women's views on the menopause and hormone replacement therapy were explored using a questionnaire given to women attending one general practice who were having hormone replacement therapy under the...

Activation of monocytic cells by monoclonal antibodies to the CD11a/18 (LFA-1) complex: mediation by Fc receptor.

Macintyre, E A, Roberts, P J, Abdul-Gaffar, R, Morgan, J, Linch, D C

IgG1 antibodies reacting with several monocytic antigens form a bridge between the specific antigen and the Fc receptors also expressed on these cells. This results in calcium mobilization and...

The digestion of bacterial macromolecules by phagocytic cells: the effect of mepacrine and ethanol.

Roberts, P J, Segal, A W

The digestion of radiolabelled DNA, RNA and protein from two species of bacteria was measured after their ingestion by neutrophils and monocytes. The Escherichia coli (W3110T-) strain was more...

Defective degradation of bacterial DNA by phagocytes from patients with systemic and discoid lupus erythematosus.

Roberts, P J, Isenberg, D A, Segal, A W

The digestion of bacterial DNA by peripheral blood monocytes was impaired both in patients with systemic lupus erythematosus (SLE) and discoid lupus erythematosus (DLE). The monocytes of these...

The uptake and release of [3-H]-2-amino-6,7-dihydroxy-1,2,3,4-tetrahydronaphthlane (ADTN) by striatal nerve terminals.

Davis, A, Roberts, P J, Woodruff, G N

A study has been made of the uptake and release of [G-3H]-2-amino 6,7-dihydroxy-1,2,3,4-tetrahydronaphthalene (ADTN) by crude striatal synaptosomes of the rat. 2 Uptake was rapid,...

2-chloroadenosine attenuates kainic acid-induced toxicity within the rat straitum: relationship to release of glutamate and Ca2+ influx.

Arvin, B., Neville, L. F., Pan, J., Roberts, P. J.

1. The mechanism by which 2-chloroadenosine (2-chloroado) exerts a neuroprotective action against the excitotoxic effect of kainic acid (KA) when injected into the rat striatum was investigated. 2....

(S)-homoquisqualate: a potent agonist at the glutamate metabotropic receptor.

Porter, R. H., Roberts, P. J., Jane, D. E., Watkins, J. C.

The synthetic quisqualate analogue, (S)-homoquisqualate was examined for activity at the glutamate metabotropic receptor, in relation to its ability to stimulate phosphoinositide hydrolysis in rat...

Characterization of the pharmacology and regional distribution of (S)-[3H]-5-fluorowillardiine binding in rat brain.

Hawkins, L. M., Beaver, K. M., Jane, D. E., Taylor, P. M., Sunter, D. C., Roberts, P. J.

1. This study examined the binding of the new radioligand (S)-[3H]-5-fluorowillardiine to rat brain synaptic membranes. Specific binding represented greater than 80% of the total binding and was...

Structure-activity relationships for a series of phenylglycine derivatives acting at metabotropic glutamate receptors (mGluRs).

Bedingfield, J. S., Kemp, M. C., Jane, D. E., Tse, H. W., Roberts, P. J., Watkins, J. C.

1. The actions of a series of twelve phenylglycine derivatives at metabotropic glutamate receptors (mGluRs) linked to both phosphoinositide hydrolysis (PI) and cyclic AMP were investigated. 2. PI...

Characterization of metabotropic glutamate receptor-stimulated phosphoinositide hydrolysis in rat cultured cerebellar granule cells.

Toms, N. J., Jane, D. E., Tse, H. W., Roberts, P. J.

1. The pharmacology of excitatory amino acid (EAA)-stimulated phosphoinositide (PI) hydrolysis, monitored via [3H]-inositol monophosphate accumulation, was investigated in primary cultures of rat...

The effects of (RS)-alpha-cyclopropyl-4-phosphonophenylglycine ((RS)-CPPG), a potent and selective metabotropic glutamate receptor antagonist.

Toms, N. J., Jane, D. E., Kemp, M. C., Bedingfield, J. S., Roberts, P. J.

1. In this study we describe the potent antagonist activity of a novel metabotropic glutamate (mGlu) receptor antagonist (RS)-alpha-cyclopropyl-4-phosphonophenylglycine ((RS)-CPPG) which exhibits...

Presynaptic gamma-aminobutyric acid receptors in the rat anococcygeus muscle and their antagonism by 5-aminovaleric acid.

Muhyaddin, M., Roberts, P. J., Woodruff, G. N.

1 The effects of gamma-aminobutyric acid (GABA) and related drugs on the isolated anococcygeus muscle of the rat were determined. 2 GABA caused a dose-related inhibition of the electrically-evoked...

Characterization of the binding of DL-[3H]-2-amino-4-phosphonobutyrate to L-glutamate-sensitive sites on rat brain synaptic membranes.

Butcher, S. P., Collins, J. F., Roberts, P. J.

The binding of DL-[3,4-3H] 2-amino-4-phosphonobutyric acid DL[3H]-APB to rat whole brain synaptic membranes was investigated. Binding was linear with membrane protein concentration, and optimal at...

Stimulation of rat cerebellar guanosine 3',5'-cyclic monophosphate (cyclic GMP) levels: effects of amino acid antagonists.

Foster, G. A., Roberts, P. J.

1 The ability of glutamate, aspartate and related neuroexcitants to produce large calcium-dependent increases in the levels of guanosine 3',5'-cyclic monophosphate (cyclic GMP) in immature rat...

The effect of inhibition of leukotriene synthesis on the activity of interleukin-8 and granulocyte-macrophage colony-stimulating factor

Roberts, P. J., Pizzey, A. R., Linch, D. C.

The cytokines interleukin-8 (IL-8) and granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced the extracellular release of arachidonate metabolites from ionophore-stimulated neutrophils...

The prognostic value of preoperative serum levels of CA 19-9 and CEA in patients with pancreatic cancer.

Lundin, J., Roberts, P. J., Kuusela, P., Haglund, C.

The prognostic value of preoperative serum levels of CA 19-9 and CEA was evaluated in 160 patients with pancreatic cancer. The survival of patients whose tumour marker value was below a certain...

Difference in tissue expression of tumour markers CA 19-9 and CA 50 in hepatocellular carcinoma and cholangiocarcinoma.

Haglund, C., Lindgren, J., Roberts, P. J., Nordling, S.

The expression of tumour markers CA 19-9 and CA 50, defined by the monoclonal antibodies 1116 NS 19-9 (19-9 antibody) and C 50, was studied by the immunoperoxidase technique in formalin-fixed,...

Comparison of a new tumour marker CA 242 with CA 19-9, CA 50 and carcinoembryonic antigen (CEA) in digestive tract diseases.

Kuusela, P., Haglund, C., Roberts, P. J.

The levels of CA 242, a new tumour marker of carbohydrate nature, were measured in sera of 185 patients with malignancies of the digestive tract and of 123 patients with benign digestive tract...

Gastrointestinal cancer-associated antigen CA 19-9 in histological specimens of pancreatic tumours and pancreatitis.

Haglund, C., Lindgren, J., Roberts, P. J., Nordling, S.

The expression of the gastrointestinal cancer associated antigen CA 19-9, defined by the monoclonal antibody 1116 NS 19-9, was studied by immunoperoxidase staining in routine formalin-fixed,...

Evaluation of CA 19-9 as a serum tumour marker in pancreatic cancer.

Haglund, C., Roberts, P. J., Kuusela, P., Scheinin, T. M., Mäkelä, O., Jalanko, H.

Serum concentrations of the CA 19-9 antigen were determined in 91 patients with pancreatic cancer and in 111 patients with benign pancreatic, biliary and hepatocellular diseases. The CA 19-9...

Tumour-associated trypsin inhibitor, TATI, in patients with pancreatic cancer, pancreatitis and benign biliary diseases.

Haglund, C., Huhtala, M. L., Halila, H., Nordling, S., Roberts, P. J., Scheinin, T. M., ...

The serum and urine concentrations of a tumour-associated trypsin inhibitor, TATI, were determined by radioimmunoassay in patients with pancreatic cancer and with benign pancreatic and biliary...

Comparison of CA-50, a new tumour marker, with carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) in patients with gastrointestinal diseases.

Kuusela, P., Haglund, C., Roberts, P. J., Jalanko, H.

Serum levels were determined in 434 patients with benign and malignant gastrointestinal diseases and compared with the serum concentrations of carcinoembryonic antigen (CEA) and alpha-fetoprotein...

CA 242, a new tumour marker for pancreatic cancer: a comparison with CA 19-9, CA 50 and CEA.

Haglund, C., Lundin, J., Kuusela, P., Roberts, P. J.

The serum expression of a novel tumour marker, CA 242, defined by monoclonal antibody C 242, was studied in 179 patients with pancreatic cancer. The results were compared with CA 19-9, CA 50 and CEA....

Preoperative serum levels of CEA and CA 242 in colorectal cancer.

Carpelan-Holmström, M., Haglund, C., Kuusela, P., Järvinen, H., Roberts, P. J.

Preoperative serum levels of CEA and CA 242 were determined in 260 patients with colorectal cancer and in 92 patients with benign colorectal diseases. The overall sensitivity of the CEA test was 43%...

Independent prognostic value of preoperative serum markers CA 242, specific tissue polypeptide antigen and human chorionic gonadotrophin beta, but not of carcinoembryonic antigen or tissue polypeptide antigen in colorectal cancer.

Carpelan-Holmström, M., Haglund, C., Lundin, J., Alfthan, H., Stenman, U. H., Roberts, P. J.

The prognostic value of preoperative serum concentrations of carcinoembryonic antigen (CEA), CA 242, tissue polypeptide antigen (TPA), specific tissue polypeptide antigen (TPS) and human chorionic...

Tissue expression of the tumour associated antigen CA242 in benign and malignant pancreatic lesions. A comparison with CA 50 and CA 19-9.

Haglund, C., Lindgren, J., Roberts, P. J., Kuusela, P., Nordling, S.

The expression of a novel tumour associated antigen CA 242, defined by the monoclonal antibody C 242, was studied by immunoperoxidase staining in formalin-fixed, paraffin-embedded tissue sections...