Search Results - (Author, Cooperation:D. Lambert)

2018-03-06

The Society of Nuclear Medicine (SNM)

0022-3123

Medicine

2018-08-07

Institute of Physics Publishing (IOP)

1748-0221

Physics

2012-12-01

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Alligators and Crocodiles/*anatomy & histology/embryology/*growth & development ; Animals ; Head ; Jaw/anatomy & histology/embryology ; Keratins ; *Mechanical Processes ; Skin/*anatomy & histology/embryology/*growth & development

2014-11-08

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

DNA/*genetics/history ; Europe ; European Continental Ancestry Group/*genetics/history ; Fossils ; Genome, Human/*genetics ; Genomics ; History, Ancient ; Humans ; Male ; Siberia

2018-10-26

American Society of Hematology (ASH)

0006-4971

1528-0020

Biology

Medicine

Thrombocytopenia, Platelets and Thrombopoiesis, Clinical Trials and Observations

2018-12-15

The American Association for Cancer Research (AACR)

1078-0432

1557-3265

Medicine

2018-03-23

BMJ Publishing Group

0022-2593

1468-6244

Medicine

2018-07-06

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Anthropology, Genetics

2018-12-20

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

1089-7550

AIP Digital Archive

Physics

The optical properties of undoped and modulation-doped AlGaN/GaN single heterostructures (SHs) grown by metalorganic chemical vapor deposition are investigated at low temperature using photoluminescence measurements. The formation of a two-dimensional electron gas at the heterojunction is verified by temperature-dependent Hall mobility and 300 K capacitance-voltage measurements. Radiative recombination is observed between the electrons in two-dimensional quantum states at the heterointerface and the holes in the flat-band region or bound to residual acceptors both in undoped and modulation-doped AlGaN/GaN SHs. These peaks disappear when the top AlGaN layer is removed by reactive ion etching. In addition, the photoluminescence results under different laser excitation intensity and lattice temperature are also described for undoped and modulation-doped AlGaN/GaN SHs with various Al compositions and growth interrupt times. © 2001 American Institute of Physics.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: δ-Opioids mobilize Ca2+ from intracellular stores in undifferentiated NG108-15 cells, but the mechanism involved remains unclear. Therefore, we examined the effect of [d-Pen2,5]enkephalin on inositol 1,4,5-trisphosphate formation in these cells. [d-Pen2,5]enkephalin caused a dose-dependent (EC50 = 3.1 nM) increase in inositol 1,4,5-trisphosphate formation (measured using a specific radioreceptor mass assay), which peaked (25.7 ± 1.2 pmol/mg of protein with 1 µM, n = 9) at 30 s and returned to basal levels (10.6 ± 0.9 pmol/mg of protein, n = 9) within 4–5 min. This response was fully naloxone (1 µM) reversible and pertussis toxin (100 ng/ml for 24 h) sensitive. Preincubation with Ni2+ (2.5 mM) or nifedipine (1 µM) had no effect on the [d-Pen2,5]enkephalin (1 µM)-induced inositol 1,4,5-trisphosphate response, and K+ (80 mM) was unable to stimulate inositol 1,4,5-trisphosphate formation, indicating Ca2+ influx-induced activation of phospholipase C is not involved. Preincubation with the protein kinase C inhibitor Ro 31-8220 (1 µM) enhanced, whereas acute exposure to phorbol 12,13-dibutyrate (1 µM) abolished, the [d-Pen2,5]enkephalin (0.1 µM)-induced inositol 1,4,5-trisphosphate response, suggesting protein kinase C exerts an autoinhibitory feedback action. [d-Pen2,5]Enkephalin also dose-dependently (EC50 = 2.8 nM) increased the intracellular [Ca2+], which was maximal (24 nM increase with 1 µM, n = 5) at 30 s. This close temporal and dose-response relationship strongly suggests that δ-opioid receptor-mediated increases in intracellular [Ca2+] results from inositol 1,4,5-trisphosphate-induced Ca2+ release from intracellular stores, in undifferentiated NG108-15 cells.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: The cellular mechanisms underlying opioid action remain to be fully determined, although there is now growing indirect evidence that some opioid receptors may be coupled to phospholipase C. Using SH-SY5Y human neuroblastoma cells (expressing both μ-and δ-opioid receptors), we demonstrated that fentanyl, a μ-preferring opioid, caused a dose-dependent (EC50= 16 nM) monophasic increase in inositol (1,4,5)trisphosphate mass formation that peaked at 15 s and returned to basal within 1–2 min. This response was of similar magnitude (25.4 ± 0.8 pmol/mg of protein for 0.1 μM fentanyl) to that found in the plateau phase (5 min) following stimulation with 1 mM carbachol (18.3 ± 1.4 pmol/mg of protein), and was naloxone-, but not naltrindole-(a δ antagonist), reversible. Further studies using [d-Ala2, MePhe4, Gly(ol)5]enkephalin and [d-Pen2,5]enkephalin confirmed that the response was specific for the μ receptor. Incubation with Ni2+ (2.5 mM) or in Ca2+-free buffer abolished the response, as did pretreatment (100 ng/ml for 24 h) with pertussis toxin (control plus 0.1 μM fentanyl, 26.9 ± 1.5 pmol/mg of protein; pertussis-treated plus 0.1 μM fentanyl, 5.1 ± 1.3 pmol/mg of protein). In summary, we have demonstrated a μ-opioid receptor-mediated activation of phospholipase C, via a pertussis toxin-sensitive G protein, that is Ca2+-dependent. This stimulatory effect of opioids on phospholipase C, and the potential inositol (1,4,5)trisphosphate-mediated rises in intracellular Ca2+, could play a part in the cellular mechanisms of opioid action.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

Three experiments are described, two with S215 meadow fescue and one with S37 cocksfoot, all grown for seed, during which all new tillers, soon after their appearance, were labelled at intervals of a month—a total of nearly 12,000 tillers. Whatever the first date of observation, the earliest tillers were always found to have contributed the largest proportion of the ears present at harvest. In one experiment applied nitrogen caused an increase in the number of tillers and ears, without however affecting the percentage contribution of the earliest tillers to the final crop of ears. The importance of the autumn period of tillering is stressed.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

An experiment is described in which timothy, grown for production of seed, was cut once annually on dates ranging from 23 October to 24 May. New tillers in selected plants were labelled at monthly intervals during autumn and winter for 2 years, to determine the pattern of production of tillers and to assess the reproductive development of categories of tillers. The majority of tillers were produced in autumn, but production was continuous throughout the winter. There was a big increase from the first to the second year in the total number of tillers produced, but neither the pattern nor amount of tiller production was affected by cutting. The % of fertile tillers was highest in the oldest tillers, and was affected little by the increase in the number of tillers from the first to the second year; cutting had little effect on the % fertility except where floral primordia were removed by the cut on 24 May. In all treatments at least 90% of the ears at harvest were produced by tillers initiated the previous autumn. The penetration of light to the base of the plants was increased considerably by cutting, but it is concluded that interception of light by the whole plant is more beneficial than an increase in the penetration of light into the plant and a concomitant reduction in the total interception of light by the plant.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

An experiment is described in which nitrogen was applied in relation to the physiological stage of development in cocksfoot grown for seed. All applications of N increased the yield of seed, but applying all the N during the phase of autumnal tillering was less effective than applying it at stages of development in spring (beginning of vernal growth, initiation of inflorescences, complete differentiation of inflorescences), or in autumn and spring, because of a decrease in the number of tillers which survived to flower in the following year. Differences due to the stage of development at which N was applied in spring were small. Primary effects of N were to increase the number of tillers and ears per plant, and to accelerate the rate of development of inflorescences; in addition, N advanced the date of initiation of inflorescences without similarly advancing the date of complete differentiation of inflorescences. It is concluded that a long period between the initiation and complete differentiation of the inflorescence is conducive to high yields of seed.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

An experiment is described in which cocksfoot, grown for production of seed, was cut annually for 3 years in either autumn, winter or spring. No significant increases in yield of seed/ac were obtained from any treatment compared with an uncut control, and a cut in late April in one year seriously reduced the yield of seed. Additional N applied after a defoliation in October did not increase the yield of seed compared with that from plots which were cut at the same time but not fertilized. The production of tillers was not affected by cutting on any date. The percentage fertility of tillers was increased by cutting in the first year, when the number of tillers was smallest; the fertility was less consistently affected in the second year, and was generally unaffected in the third year. The weight of seed produced per ear was usually reduced by the cutting treatments. In the third year of the experiment it was shown that the penetration of light to the base of the shoots was increased substantially by defoliation, but it is deduced that maximum interception of light by the whole plant is more important for the production of seed than increasing by cutting that proportion which penetrates to the base of the plant.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

An experiment to determine the effect of applying high levels of N on the seed yield of S37 cocksfoot is described. Increasing the rate of application in the range 174–1044 Ib N/ac/annum did not substantially increase yield, except where 1044 Ib N was applied in monthly lots in 1960–1; in some instances yield was significantly reduced by increased N application, apparently as a result of increased frost susceptibility. It is concluded that an application of about 174 lb N/ac/annum is the maximum desirable if there is a danger of frost.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

The dates of their first appearance and the dates of flowering were recorded monthly over three years from time of sowing for all tillers produced by S215 meadow fescue plants growing in simulated sward conditions in large concrete pots outdoors. The results are expressed and discussed in terms of the percentage contribution of inflorescences by tillers in relation to their chronological and ontogenetic age. The latter appeared the more important. The major contribution of inflorescences was made by primary tillers in the first harvest year, by secondary and tertiary tillers in the second year and by tertiary and quaternary tillers in the third year. The chronological age at which tillers could flower ranged from 3 to 33 mouths.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

In each of a series of sub-divided containers, two plants of cocksfoot (Dactylis glomerata) were planted in one of four arrangements to study the effects of: (a) no competition; (b) aerial competition, considered to be competition for light; (c) edaphic competition, considered to be competition for nitrogen; (d) full (aerial plus edaphic) competition, for light and N.The weight of seed produced per plant was reduced by aerial compeition, but not by edaphic competition, except where aerial competition also existed. With the exception of the seed, the weights of the components of the plants at harvest were reduced substantially by edaphic competition.The concentration of N in the various parts of the plant varied considerably, but only in the culms was it significantly affected by treatment so that the uptake of N was approximately proportional to the weight of the plant. Edaphic competiton gave most tillers per plant and full competition least. Aerial competition decreased the number of ears per plant.

Electronic Resource

1365-2494

Blackwell Publishing Journal Backfiles 1879-2005

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

Leaf-area index was increased by nitrogen application, but the increase was restricted by frequent cutting, which limited the incidence of high leaf-area indices. Timothy swards had higher leaf-area indices than meadow-fescue swards between April and mid-July, the period in which maximum values were recorded. N significantly increased the leaf area per g of leaf (leaf-area/leaf-weight ratio) at the beginning of the experiment, but not thereafter; the effect of cutting on this ratio varied with the date of cutting. Leaf areas per g of leaf were similar for the 2 species at the beginning and end of the experiment, but in mid-summer values for timothy increased whilst those for meadow fescue decreased. The relationship between leaf-area index and yield of dry matter is discussed.

Electronic Resource