Search Results - (Author, Cooperation:W. Kennedy)

2018-06-23

The American Society for Biochemistry and Molecular Biology (ASBMB)

0021-9258

1083-351X

Biology

Chemistry and Pharmacology

2015-12-04

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Animals ; Breast Neoplasms/genetics/*physiopathology ; Carcinoma, Ductal, Breast/genetics/*physiopathology ; Cell Lineage/genetics ; *Cell Transformation, Neoplastic ; Cells, Cultured ; DNA Barcoding, Taxonomic ; Female ; Gene Expression Profiling ; Heterografts ; Humans ; Lentivirus/genetics ; Mammary Glands, Human/cytology/*physiopathology ; Mice ; Mice, Inbred Strains ; Mice, SCID ; Proto-Oncogene Proteins/genetics ; Time Factors ; Transduction, Genetic ; ras Proteins/genetics

2018-03-07

Nature Publishing Group (NPG)

2041-1723

Biology

Chemistry and Pharmacology

Natural Sciences in General

Physics

1432-0800

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Medicine

Electronic Resource

2018-01-20

Institute of Physics Publishing (IOP)

1748-0221

Physics

1077-3118

AIP Digital Archive

Physics

We report the successful fabrication and characterization of a high Tc superconducting microwave cavity. The cavity made of bulk Y1Ba2Cu3Oy (Tc=93 K) and dielectrically loaded with sapphire was resonant at 8.00 GHz in the TE011 mode. At 77 K the Q was 104, which represents an improvement of a factor of 11 from the normal state. At 4.2 K the Q was nearly 105. The temperature dependence of the Q correlates extremely well with the microwave surface resistance of a test sample measured independently, clearly showing that the Q was limited by the intrinsic materials preparation and not by extraneous factors.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report the fabrication and high-frequency characterization of single crystals of Y1Ba2Cu3O7 with extremely sharp microwave transitions. The 10 GHz surface resistance Rs is less than 400 μΩ, at temperatures 4 K below the transition temperature. The electrodynamic characteristics of these crystals were examined via several measurements, and we demonstrate that high quality crystals which show very low Rs also possess small penetration depths λ(0)=1600 A(ring) and small magnetic field effects on the penetration depth characterized by k(0)≡(dλ/dB2)T→0=10−3 A(ring)/G2. In polycrystals, and even in poor single crystals, the presence of Josephson junctions of typical effective area ∼4 μm2 leads to poor microwave properties, with electrodynamic parameters orders of magnitude larger.

Electronic Resource

1089-7623

AIP Digital Archive

Physics

Electrical Engineering, Measurement and Control Technology

We have devised and implemented a novel technique that has the required sensitivity to enable measurements of the complex surface impedance (Zs) of high Tc superconducting materials between 4.2 K and at least 200 K. The essential ideal is to employ a superconducting high-Q cavity resonator operated at an ambient temperature of 4.2 K. The sample, mounted on a sapphire rod, is placed inside the cavity at a high magnetic field location, and is thermally insulated from the cavity walls, enabling external control of the sample temperature between 4.2 and 200 K. The cavity characteristics are dominated by the sample properties—the Pb walls maintained at 4.2 K contribute negligibly. Measurement of the cavity Q and resonant frequency enables the measurement of Zs as a function of the sample temperature. The technique is applicable to both bulk and thin-film materials. We have used this technique with success to measure Zs, at 9.58 GHz, for bulk Y1Ba2Cu3Oy and La1.85Sr0.15CuO4 over a temperature range from 4.2 to 100 K.

Electronic Resource

1467-9248

Blackwell Publishing Journal Backfiles 1879-2005

Political Science

Electronic Resource

1365-2427

Blackwell Publishing Journal Backfiles 1879-2005

Biology

SUMMARY. A massive population of the common dinoflagellate Ceratium hirundinella developed in Heart Lake. Ontario, Canada during the summer of 1976 and its sudden collapse and subsequent decomposition depleted dissolved oxygen and resulted in a fish-kill in the lake. The lake was being artificially mixed at the time by supplying compressed air to the bottom waters and the limnological events contributing to the development of the Ceratium population and its collapse appear to be closely related to the artificial destratification process. Artificial destratification during 1976 precluded the development of blue-green algue. The process also led to an increase in the density of herbivorous zooplankters which controlled the development of smaller planktonic algae. Ceratium flourished in Heart Lake because there was little competition for nutrients from other algae and because Ceratium cells are too large to be grazed by the zooplankton. The maximum size of the Ceratium population (53 mm3 1−1) is apparently the highest biomass reported in the literature and its collapse may have been related to a depletion of inorganic nitrogen. There is apparently no previously published record of a Ceratium-induced fish-kill in a freshwater lake.

Electronic Resource

1365-3091

Blackwell Publishing Journal Backfiles 1879-2005

Geosciences

A study of septarian concretions from late Cretaceous shale sequences of Texas and northern Mexico reveals complex burial-exhumation histories. First generation concretions and pre-fossilized moulds formed in silty clays before significant compaction occurred. Syneresis cracks developed and were filled by length slow fibrous calcite with a decrease in iron content toward the centre of each vein; in some cases this was succeeded by growth of equant or bladed calcite. Subsequent erosion of enclosing sediment caused collapse and break up of concretions, leaving fragments and some unbroken concretions exposed to encrustation and boring on the sea floor. These were subsequently buried and enclosed in a second generation of concretions, which also developed syneresis cracks. The calcite that filled these latter cracks was generally bladed (sometimes followed by equant calcite) and contains more iron toward the centre of the vein. Differences between the calcite filling first and second generation septarian veins indicates changing diagenetic regimes during burial in the marine environment, without a major shift in diagenetic conditions, such as the introduction of meteoric waters. These conclusions have significant implications to cementation in ancient limestones, which show textural and chemical sequences similar to those present in the septarian concretions described.

Electronic Resource

1365-3091

Blackwell Publishing Journal Backfiles 1879-2005

Geosciences

The Upper Cretaceous chalks of southern England are a thick sequence of rhythmically bedded, bioturbated coccolith micrites, deposited in an outer shelf environment in water depths which varied between 50 and 200–300 m.The products of sea floor cementation are widely represented in the sequence, and a series of stages of progressive lithification can be recognized. These began with a pause in sedimentation and the formation of an omission surface, followed by (a) growth of discrete nodules below the sediment-water interface to form a nodular chalk, erosion of which produced intraformational conglomerates. (b) Further growth and fusion of nodules into continuous or semicontinuous layers: incipient hardgrounds. (c) Scour, which exposed the layer as a true hardground. At this stage, the exposed lithified chalk bottom was subject to boring and encrustation by a variety of organisms, whilst calcium carbonate was frequently replaced by glauconite and phosphate to produce superficial mineralized zones. In many cases, the processes of sedimentation, cementation, exposure and mineralization were repeated several times, producing composite hardgrounds built up of a series of layers of cemented and mineralized chalk, indicating a long and complex diagenetic history.Petrographic study of early cemented chalks indicates lithification was the result of the precipitation of small crystals on and between coccoliths and coccolith fragments. By analogy with known occurrences of early lithification in Recent deeper water carbonates, the cement is believed to have been either high magnesian calcite or aragonite, and more probably the former. The vast scale of operations involved in the cementation process precludes carbonate in expelled pore fluids as the source of cement, whilst quantities of aragonite incorporated in sediment are also inadequate. This, plus the observed association of horizons of early lithification with pauses in sedimentation associated with omission surfaces suggests seawater as a source of cementing materials.Stratigraphic studies indicate that processes of early lithification leading to hardground formation proceeded to completion in intervals to be measured in tens or hundreds of years. Regional studies suggest that early lithification characterized relatively shallow water phases associated with regional regression over the whole of the area, whilst in detail, the distribution of mature mineralized hardground complexes is strongly correlated with sedimentary thinning and condensation over small areas and the buried flanks of massifs. Early cementation in more basinal areas is typically in the form of nodular developments and incipient hardgrounds, whilst day contents in excess of a few percent appear to have inhibited early lithification.The striking rhythmicity of hardgrounds and nodular chalks is no more than a particular expression of the overall rhythmicity of chalk sequences. The stage of early lithification reached in any instance is dependent on sediment type, the time interval represented by the associated omission surface and the degree of associated scour and erosion (if any).Chalk hardgrounds differ from most others described in the geological literature in their widespread distribution (individual hardgrounds may cover up to 1500 km2), the presence of striking glauconite and phosphate replacements of lithified carbonate matrices, their frequently sparse epifaunas, and boring infaunas dominated by clionid sponges. These differences reflect the deeper water shelf setting of the chalk, and the more open marine, oceanic circulatory system, both strikingly different from the setting of other, shallower water hardgrounds.Litho- and biostratigraphic variation in the chalk sequences of the area studied are summarized in an appendix.

Electronic Resource

1365-3091

Blackwell Publishing Journal Backfiles 1879-2005

Geosciences

Large scale sedimentary structures present in the Upper Turonian to Santonian chalks of Haute Normandie (northern France) represent the remains of a carbonate bank complex which formerly extended over an area of at least 1500 km2. Cliff exposures along the Channel coast from St Valéry-en-Caux to Cauville and along the Seine from Sandouville to Lillebonne show sections of banks up to 50 m high and 1500 m across, their internal structures picked out by hardgrounds, nodular chalks and horizons of burrow flint.Associated with banks are slump sheets up to 20 m thick, slump scars, sedimentary breccias, injection phenomena and faults contemporaneous with sedimentation. Later diagenetic features include extensive dolomitization and silicification.These structures compare closely with the Waulsortian banks of the Palaeozoic, and bryozoan bioherms known from the Upper Cretaceous and Palaeocene of Denmark. Frame-building, sediment trapping and stabilizing organisms are absent, and bank development and stabilization was probably due to a plant covering, either algal or of marine angiosperms. Banks generated much of their own sediment, whilst a pelagic constituent (calcareous nannofossils and Foraminiferida) is also present.The distribution of the bank complex is related to a basement controlled swell area, whilst the life of the complex was limited to a relatively shallow water, regressive episode in the predominantly transgressive Upper Cretaceous history of the region.Les falaises littorales du Pays de Caux comprises entre Antifer et St Valèry-enCaux, et les affleurements de la basse vallée de la Seine permettent d'observer des formations du Turonien supérieur-Sénonien inférieur qui présentent des stratifications irrégulières soulignées par de nombreux hardgrounds, des horizons de craie noduleuse et des cordons de silex. Ces structures sont identifiées à des accumulations de calcilutite et calcarénite sous forme de bancs sous-marins dont la hauteur peut atteindre 50 m et qui couvrent une surface supérieure à 1500 km2; ils apparaissent au-dessus de hardgrounds subhorizontaux qui indiquent un haut-fond régional stable. Des glissements sous-marins sont associés à ces bancs et engendrent des niveaux avec des déformations souples atteignant 20 m d'épaisseur. Des brèches apparaissent localement et contiennent des blocs basculés de hardgrounds fragmentés lors du glissement; on y observe aussi de petites failles intrasédimentaires et des phénomènes d'injection. Aucun organisme constructeur ou capable de piéger et retenir le sédiment n'a été observé. La stabilisation de ces bancs serait due à une couverture végétale (algues ou angiospermes marines) dont on sait qu'elle peut disparâitre sans laisser de trace lors de la fossilisation. La croissance de ces bancs serait réalisée par un apport de sédiment comprenant une part de nourrissage autochtone comme cela existe pour les bancs récents en eau peu profonde, associée au dépôt d'une fraction pélagique.

Electronic Resource

0095-2583

Economics

0029-2397

English, American Studies

History

0029-2397

English, American Studies

History

0029-2397

English, American Studies

History

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background : Recent data suggest a role for high-dose oral proton pump inhibition in ulcer bleeding.Aim : To compare the cost-effectiveness of oral high-dose proton pump inhibition to both high-dose intravenous proton pump inhibition and placebo administration.Methods : The model adopted a 30-day time horizon, and focused on patients with ulcer haemorrhage initially treated endoscopically for high-risk stigmata. Re-bleeding rates were set a priori based on non-head-to-head data from the literature, and charges and lengths of stay from a national American database. Sensitivity analyses were carried across a broad range of clinically relevant assumptions.Results : Re-bleeding rates for patients receiving intravenous, oral, or placebo therapies were 5.9%, 11.8%, and 27%, respectively. The mean lengths of stay and costs for admitted patients with and without re-bleeding were 4.7 and 3 days; $11 802, and $7993, respectively. High-dose intravenous proton pump inhibition was more effective and less costly (dominant) than high-dose oral proton pump inhibition with incremental savings of $136.40 per patient treated. The oral high-dose strategy in turn dominated placebo administration. Results remained robust according to one- and two-way sensitivity analyses.Conclusion : In patients undergoing endoscopic haemostasis, subsequent high-dose intravenous proton pump inhibition is more cost-effective than high-dose oral proton pump inhibition, which in turn dominates placebo. The results from this exploratory-type cost analysis require confirmation by head-to-head prospective trials performed in Western populations.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Background : The efficacy of high-dose intravenous proton pump inhibition has recently been shown, yet its cost-effectiveness remains poorly studied.Aim : To assess the cost-effectiveness of this approach separately for American and Canadian health care settings.Methods : A validated decision model included patients with bleeding ulcers after successful endoscopic haemostasis. Probabilities were determined from the literature, and charges and lengths of stay from national databases. A third-party payer perspective was adopted over a 30-day time horizon.Results : Re-bleeding rates were 5.9% for patients who received high-dose intravenous proton pump inhibition and 22.9% for those who did not. Hospitalization costs for patients with and without re-bleeding were US$11 802 and US$7993, and CAN$5220 and CAN$2696, respectively. High-dose intravenous proton pump inhibition was more effective and less costly than the alternative of not administering it. The cost-effectiveness ratios for high-dose and no high-dose intravenous proton pump inhibition were US$9112 and US$11 819 (CAN$3293 and CAN$4284 for the Canadian case), respectively. Sensitivity and threshold analyses showed that the results were robust across a wide range of clinically relevant assumptions.Conclusion : In the USA and Canada, administering high-dose intravenous proton pump inhibition for 3 days is both more effective and less costly than not doing so for patients with bleeding ulcers after successful endoscopic haemostasis.

Electronic Resource

1365-2133

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary In this study the number and function of sweat glands on the dorsum of the hand and foot were evaluated using a silastic imprint method. Twenty patients. 11 females and nine males with either alopecia areata. alopecia totalis. or alopecia universalis were included in the study. Patients showed a significant decrease in activated sweat-gland number and function compared to matched controls (P〈0.001). There was no significant relationship between the degree of sweat-gland dysfunction and extent of hair loss, concurrent illnesses, or treatment. These findings suggest that eccrine sweat-gland function is compromised in patients with alopecia areata.

Electronic Resource