Search Results - (Author, Cooperation:J. D. Robinson)

2015-08-22

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—(1) A microsomal preparation from rat brain accumulated calcium by an ATP-dependent process during incubation in a hypotonie medium. Accumulation was reduced in media containing 100 mm-NaCl, 100 mm-KCl or 100 mm-choline chloride or 200 mm-sucrose. During prolonged incubations NaCl further decreased calcium content unlike the other ions; this suggests a release of accumulated calcium by NaCl.(2) Microsomes that had accumulated calcium during a prior incubation (‘preloaded microsomes’) lost calcium during a subsequent incubation. NaCl specifically increased the rate of loss of calcium. Ouabain had no effect on the NaCl-induced efflux.(3) Loss of calcium from preloaded microsomes, both with and without NaCl, had a high temperature coefficient. Measurements of monovalent cation content showed no correlation of either the uptake or loss with a simple ion-exchange process and the accumulated calcium did not exchange with calcium in the medium.(4) ATP specifically reduced the efflux of calcium from preloaded microsomes. Although the diminished loss of calcium could be attributed in part to reaccumulation, this was not the only mechanism since ATP also reduced the loss from continuously perfused microsomes preloaded with calcium.(5) A series of neurotropic drugs had little effect on the efflux of calcium. Low concentrations of chlorpromazine decreased calcium retention less than 20 per cent.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

〈list xml:id="l1" style="custom"〉1A microsomal preparation from rat brain accumulated 45Ca in the presence of ATP. The uptake of calcium was associated with a corresponding uptake of 32P from [γ-32P]ATP, with a 32P:45Ca molar ratio of about 0·65.2Microsomes that were first loaded with 46Ca lost radioactivity during a subsequent incubation in the absence of ATP; efflux of previously accumulated 32P (from ATP) corresponded with the calcium efflux. By contrast, the uptake of 14C from [8-14C]ATP was far less than of 32P, and the efflux did not follow calcium efflux. Thus the movement of 32P probably represented the phosphate anion in association with calcium. Calcium efflux diminished with increasing pH up to 8·6.3Sodium specifically increased the rate of efflux of previously accumulated calcium. This sodium-induced efflux was associated with a corresponding efflux of 32P (from ATP) and had a pH optimum near 7·8. It was not accompanied by a change in the amount of retained adenine nucleotides nor in the pattern of ATP metabolites, and was unaffected by ouabain or oligomycin.4Low concentrations of certain sulphydryl inhibitors blocked the sodium-stimulated efflux with little effect either on efflux in the absence of sodium or on 45Ca accumulation.5Higher concentrations of these inhibitors, associated with an increase binding of the reagent, caused a generalized efflux of 45Ca and an inhibition of accumulation. The lipid solubility of a series of mercurial reagents corresponded with efficacy in promoting efflux; this suggested that this second class of reactive sites lay within a lipoidal permeability barrier.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

We re-examine the ionization-detected ultraviolet absorption spectrum of the 3pπ 2Π←X 2A′ transition in HCO and DCO using a high-power visible laser to enhance the observation of first-photon resonant features. This technique, which we term here, assisted REMPI, significantly improves the signal-to-noise ratio of the spectrum, making many weak vibronic sub-bands visible for the first time. A comprehensive fit to the structure evident in a progression of bending levels from (000) to (040) refines the assignment of Song and Cool [X. M. Song and T. A. Cool, J. Chem. Phys. 96, 8664 (1992)] to yield a set of rotational constants that vary with K in relation to v2, together with a higher-order contribution to the Renner–Teller splitting in HCO, which is mirrored in DCO for all levels but (040). The (040) band falls at a frequency that is commensurate with that of CD stretch, and Fermi resonance between 3pπ 2Π(1000)Π and the higher-energy (040) K=1(Π) component gives rise to an added splitting that increases the energy of this (040) component and causes an apparent increase in the Renner parameter. © 2002 American Institute of Physics.

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Spatio-temporal development of brown rot (Monilinia fructigena) on apple and pear was monitored in an apple (cv. Cox) orchard and a pear orchard of several cultivars over several years. Disease on individual trees was recorded weekly from July to harvest, individual fruits with brown rot were tagged but not removed and rot-origin identified. On apple cv. Cox and pear (cvs Conference and Comice), all primary rot arose from infection via wounds caused by insects, birds and growth cracks. Birds were the most important wounding agents on pear in the field. Secondary (fruit-to-fruit contact) rot was considerably less than primary rot, especially for pear. Incidence of disease (percentage of fruits with brown rot) increased gradually from late July up to harvest; the final disease incidence varied with seasons and cultivars, ranging from 1 to 11%. For pear, Comice had greater incidence than Conference. Significant aggregation of diseased fruits among trees was detected for assessment dates when the overall incidence of disease was greater than 0·5%. On Cox and Conference, significant correlation of disease incidence between adjacent trees or trees separated by one or more trees (i.e. spatial lag measured as units of distance between adjacent trees) was detected, but there was no clear relationship between the correlation, the distance or time. For Comice, there was consistent and significant positive correlation of brown rot incidence over 3 years. It is speculated that behavioural characteristics of wounding agents may have played an important role in influencing the spatio-temporal dynamics of brown rot on apple and pear.

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Experiments were conducted to investigate the effects of temperature and relative humidity (RH) on the in vitro germination and viability of conidia of the apple brown rot fungus (Monilinia fructigena), and on colonization and sporulation on detached fruits by M. fructigena. Conidia only germinated under near-saturation humidity (≥ 97% RH) and the rate of germination initially increased with temperature to a maximum at ≈ 23–25°C and then decreased. Conidia germinated rapidly – more than 70% of viable conidia had germinated within 2 h at 20 and 25°C. The rate of colonization on detached fruits increased log-linearly with increasing temperature. Sporulation on detached fruits was not observed at 5 or 25°C; sporulation appeared to be unaffected by either temperature (10–20°C) or RH (45–98%) once infection was established. Detached conidia remained viable for a long period of time, up to 20 days, the longest assessment time in this study, depending on storage temperature (10 or 20°C) and RH (45 or 85%). Temperature appeared to be more important than RH in affecting conidial viability. Low temperature and high RH resulted in reduced loss of conidial viability. Storage at 10°C and 85% RH for up to 20 days appeared not to affect conidial viability. These results indicate that environmental conditions during the main UK growing seasons are unlikely to be limiting factors for the development of brown rot on apple.

Electronic Resource

1365-3059

Blackwell Publishing Journal Backfiles 1879-2005

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

The effects of temperature on the length of the incubation and latent periods of hawthorn powdery mildew, caused by Podosphaera clandestina, were studied. At constant temperatures over the range 10–28°C, the incubation period ranged from 5 to 14 days and the latent period from 5 to 16 days; no visible colonies had developed at 30°C after 15 days. The relationships between temperature and the rates of fungus development within the incubation and latent periods were well described by a nonlinear model. The resulting curves were asymmetrically bell-shaped with an optimum temperature of approximately 23°C. The lengths of the incubation and latent periods under fluctuating temperatures were also determined, and were used to evaluate the models developed from constant temperature experiments for their accuracy of prediction. The incubation and latent periods under fluctuating temperature regimes were predicted using a rate-summation scheme with a time step of 24 min, by integrating the respective incubation and latent rate functions obtained under constant temperatures. The predicted incubation or latent periods agreed well with the observed values. Under constant temperature the interval between the times when symptoms and sporulation on the same leaflet were first observed was very short, on average 〈1 day, and was not significantly correlated with temperature. However, this interval was negatively correlated with mean temperature under fluctuating regimes.

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Failure of the material to act on the stored2 or anoxic3 ileum (Table 1), and the sensitivity of the activity to atropine suggested that the substance may act by releasing acetylcholine from the nerve plexus in the wall of the ileum. This inference was strengthened by investigations with a ...

Electronic Resource

1432-0800

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Medicine

Electronic Resource

1432-0800

Springer Online Journal Archives 1860-2000

Energy, Environment Protection, Nuclear Power Engineering

Medicine

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Resealed ghosts were prepared from fresh, human red blood cells, following the procedure of Bodemann and Passow2 and Bodemann and Hoffman3. Cells, washed three times in 160 mM choline chloride-10 mM Tris-HCl (pH 7.4), were suspended at 50% haematocrit in isotonic Tris-HCl (166 mM, pH 7.4) at 0 C, ...

Electronic Resource

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] Male rats (300-350 g) were injected intraperitoneally with (2-14C)histamine (18 c/mmole) or uniformly labelled (14C)-L-histidine (240 c./μmole) and decapitated after specified intervals. Organs were homogenized in 5 per cent trichloroacetic acid (TCA), centrifuged, and the supernatant solution ...

Electronic Resource

1432-198X

Springer Online Journal Archives 1860-2000

Medicine

Electronic Resource

1432-1041

chlordiazepoxide ; alcoholic liver disease ; pharmacokinetics

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Medicine

Summary The clearance of chlordiazepoxide from the systemic circulation was studied in 20 subjects which included 15 patients with alcoholic hepatitis and 5 normal volunteers. The half-life for the appearance of the drug in the systemic circulation was found to increase exponentially with age (r=0.73, P〈0.0005) and was independent of the presence of alcoholic hepatitis. The metabolic clearance of chlordiazepoxide was significantly lower in the patients than in the normal subjects (7.6 compared to 13.8 ml/kg-h, P〈0.005). Linear regression analysis revealed a significant correlation between clearance and albumin (r=0.77, P〈0.00005). However, the predictive value of this relationship was shown to be minimal. Multiple regression analysis produced only a slight improvement in the correlation when both albumin and lactate dehydrogenase were used as variables (r=0.83, P〈0.00005). In six of the patients, a second clearance study was conducted three weeks following their initial one. All repeat subjects showed improvement both clinically and as reflected by their laboratory tests for liver injury, but there was not a significant change in their clearance of chlordiazepoxide. Multiple regression analysis of the clearance data on the initial and repeat subjects showed a significant correlation between clearance and the variables age, albumin, and lactate dehydrogenase (r=0.91, P〈0.0025). This relationship suggests that over a short period of time (where age can be considered constant) changes in albumin and lactate dehydrogenase could be potentially useful in predicting clearance changes in a single individual.

Electronic Resource

1435-1536

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Zusammenfassung Betrachtet man ein 3-Phasen-System, in welchem ein Tropfen der Phase 1 sich der Grenzfläche zwischen Phase 2 und Phase 3 nähert, so sieht man, daß, falls die Dichte der Phasen verschieden ist, der unter dem Tropfen abfließende Film nicht kugelförmig ist. Die Dimensionen des Tropfens wurden theoretisch vorausgesagt, indem der Tropfen in einen oberen und einen hängenden Teil aufgeteilt wurde. Diese Dimensionen stimmen sowohl mit den in einem System experimentell erhaltenen Werten überein als auch für den Fall, daß ein oberflächenaktiver Stoff im abfließenden Film vorhanden ist, unter der Annahme, daß die Grenzflächenspannung ihren minimalen Gleichgewichtswert erreicht. Reißt der aus Phase 2 bestehende abfließende Film, so kann der Tropfen an der Grenzfläche verweilen oder direkt durch sie hindurchtreten, je nach Größe des Auftriebs und der Grenzflächenkräfte. Tritt der Tropfen direkt durch die Grenzfläche in die Phase 3, so wird er gänzlich durch einen Film der Phase 2 umgeben. Reißt dieser Film, so kehrt ein kleiner Tropfen der Phase 2 zur Grenzfläche zurück.

Summary In a three phase system the shape of the draining film beneath a liquid drop of phase 1 approaching a deformable liquid-liquid interface between phases 2 and 3 is not spherical when the densities of the phases differ. The drop dimensions have been predicted theoretically by splitting the drop into a sessile part and a pendant part. These dimensions agree with those experimentally obtained for a pure system and also when surface active agent is present in the draining film if the interfacial tension is assumed to approach its minimum equilibrium value. After rupture of the draining film of phase 2 the drop may remain at the interface or pass through it depending on the magnitude of the bouyancy and interfacial forces. Alternatively the drop may pass straight through the interface into phase 3 and become completely enveloped by a film of phase 2; when this finally ruptures a small drop of phase 2 returns to the interface.

Electronic Resource

1052-9306

Chemistry ; Analytical Chemistry and Spectroscopy

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

The characterization of two abnormal human haemoglobins by fast atom bombardment (FAB) mapping is presented. The first variant, called ‘R’, exhibits a tryptic FAB map identical to that of normal haemoglobin. However, using Staphylococcus protease V8, a peptide containing the carboxyl end of the β-chain exhibits a mass shift down to 300 mass units. This clearly indicates the deletion of the two last amino acids of the β-chain. The second variant, called ‘Grenoble’, is due to two different modifications of the β-chain. The location of the Pro → Ser exchange on peptide T5 is achieved by the collisionally activated dissociation mass analyzed ion kinetic energy spectra of the corresponding [MH]+ ion. The m/z value of that peptide indicated a supplementary acid → amide modification, which was located by amino acid sequencing using chemical methods. This work concludes with the necessity of using complementary methods for achieving rapid determinations of abnormal proteins with minute amounts.

4 Ill.

Electronic Resource