Search Results - (Author, Cooperation:J. McCullough)

2015-12-05

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Biopolymers/chemistry ; Cell Membrane/chemistry/ultrastructure ; Cryoelectron Microscopy ; Endosomal Sorting Complexes Required for Transport/*chemistry ; Humans ; Oncogene Proteins/*chemistry ; Protein Structure, Secondary ; Protein Structure, Tertiary

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] "DETER FREUCHEN, speaking from his long -*- experience in the Arctic, has said recently that "only when modern times came in did the exploration of the Polar regions begin to amount to anything real. The invention of the Primus stove did more than anything else. After that came the dog sledge." ...

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The kinetics of the production and dark-decay of index gratings in chromium-doped bismuth germanium oxide Bi12GeO20 (BGO) and undoped BGO were investigated as a function of temperature from room temperature to about 500 K. During the write process in undoped BGO the gratings show a fast leading edge peak, which drops quickly to a steady saturated value. The leading-edge peak does not change significantly at the higher temperatures. Grating production was much slower in the BGO:Cr samples and the gratings grew monotonically throughout the 0.5 s write interval. At room temperature the gratings in BGO:Cr are highly persistent. A grating written at room temperature retains 70% of its initial strength after 24 h when it was read only once an hour. Optical erasure plays a major role in the decay of such gratings; reading the grating every 6 min reduced its strength to 48% of its initial value after 24 h. The grating written at room temperature and monitored as the sample was heated decayed within the same 10 K temperature range as the photochromic absorption bands. As expected, undoped BGO shows a rapid dark decay at room temperature that becomes faster at higher temperatures. © 2001 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The kinetics of production and dark decay of index gratings in Bismuth Silicon Oxide was investigated as a function of write-beam intensity at 300 K and of temperature over the 20–300 K temperature range. At 300 K and an intensity of about 200 mW/cm2 the gratings show a fast leading-edge peak which drops to a steady saturated value. At lower intensities the peak slows and broaden, but the grating strength at saturation remains the same. As the temperature is lowered the gratings grow more slowly, and the peak disappears at about 200 K. The slowing and disappearance of the peak are probably related to the large decrease in electron mobility in this temperature range. Below 225 K the grating strength at the end of the 500 ms write time grows significantly and reaches a maximum in the 125–150 K temperature region. The dark decays disappear quickly for temperatures down to about 180 K. At lower temperatures the decays become much slower and become persistent below 60 K. The largest change appears between 150 and 123 K. A persistent grating was written at 20 K, and its strength was measured as the sample warmed. The persistent grating annealed out between 110 and 150 K. The slowing of the dark decays and the anneal of the persistent grating correlate with the reported recovery of Fe3+. © 2001 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Phosphorus is one of several dopants that electronically compensate the native deep donor responsible for the yellow coloration observed in bismuth silicon oxide (BSO). Low-temperature optical absorption measurements of a series of Czochralski-grown P-doped BSO crystals show that ∼0.1–0.15 at. % P is needed in the sample to fully remove the yellow coloration. The absorption cutoff in the fully compensated P-doped sample was at 3.2 eV while compensated Al- and Ga-doped samples cutoff at 3.35 eV. Excitation at 10–15 K with near band-edge light produces photochromic absorption bands. In the lightly-doped (partially bleached) samples these bands were identical to those observed in undoped BSO. In the fully bleached sample a new spectrum was observed. Its major contribution was a band centered near 1.8 eV with a weaker absorption in the blue-green. By comparison with the spectra observed in undoped and in Al-doped material before and after photoexcitation it is believed that the 1.8 eV band is due to the [PO4]− center and that the broad 2.45 eV band observed in Al- and Ga-doped BSO is due to the [BiO4]0 center. © 1995 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Doping the photorefractive material bismuth germanium oxide Bi12GeO20(BGO) with chromium significantly affects its optical properties. An absorption spectrum taken at 300 K shows that the introduction of chromium produces a strong unresolved band which overlaps the absorption cutoff of BGO and a series of smaller overlapping bands between 650 and 1100 nm. Cooling BGO:Cr to 10 K sharpens the small bands and resolves the strong band into a peak near 510 nm. This peak is responsible for the reddish-brown color of BGO:Cr. Excitation at room temperature with visible light increases the bands in the 650–1100 nm range. The production of this additional room temperature photochromic absorption is most efficient with excitation near 490 nm but extends throughout the visible. Chromium occupies the tetrahedral germanium site in BGO; and the observed spectra are consistent with a Cr4+ tetrahedral state. During crystal growth some of the chromium gives up an electron to the antisite bismuth native defect and becomes Cr5+. Exposing the sample to light returns the electron to the chromium and increases the Cr4+ absorption. The photoinduced absorption is thermally stable for temperatures up to about 425 K. This stability suggests that doping BGO with Cr should lead to room temperature persistent photorefractive gratings. © 2001 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We report a treatment that enhances and stabilizes the photoluminescence (PL) from porous Si films. Films prepared by anodization in a 50% HF/ethanol solution were annealed at 450 °C in vacuum, exposed to air, and then exposed to a remote-hydrogen plasma. Infrared absorption spectroscopy revealed that the concentration of oxygen, rather than hydrogen, was increased by the processing steps, and that silicon dihydride species had been eliminated from the surface. The PL from a treated film was initially ∼30 times more intense than from the as-etched films. The PL intensity increased with illumination time in air until a steady-state intensity was reached.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1399-3038

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Several studies have evaluated the value of cord blood IgE concentrations for predicting the risk of allergic disease in children. In all of these studies it is necessary to exclude cord blood samples in which the IgE may be falsely elevated due to admixing of maternal and fetal blood during parturition. The most common method for detecting mixing of fetal and maternal blood is measurement of cord blood IgA concentrations. We have examined the theoretical basis of IgA measurements for detecting maternal blood contamination and reexamined our own data to evaluate IgA measurements. Our data suggest that the average IgA concentration of 28. 2 μg/ml used in previous studies may not adequately exclude contaminated cord blood sample. Failure to reject contaminated cord blood samples would reduce the positive predictive value of cord btood IgE measurements.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

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

Process Engineering, Biotechnology, Nutrition Technology

Pen-reared, pan-sized salmon and trout available locally were evaluated by a trained and a consumer panel. The trained panel determined differences of baked samples on odor, texture, moistness and flavor and visual differences for flesh color, fiber structure, and brownness along the lateral tine. Highly significant differences were detected among samples for texture, flavor, color and fiber structure. Consumer evaluation of two salmon samples and a trout sample indicated no significant differences in preference among the three samples. However, the results suggest that aquaculturists must pay more attention to the organoleptically desirable features of the fish they raise.

Electronic Resource

0029-2397

English, American Studies

History

0011-2240

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Medicine

Electronic Resource

0886-1633

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Sociology

Electronic Resource

0886-1633

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Sociology

Electronic Resource

0018-506X

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Biology

Electronic Resource

0378-4347

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Chemistry and Pharmacology

Electronic Resource

1600-051X

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract Systemic and topical administration of non-steroidal anti-inflammatory drugs (NSAIDs) has been shown to reduce periodontal disease progression in both animal models and human subjects. Our present research focuses on single enantiomers of these agents to examine whether enantiospecific therapy will be efficacious in slowing periodontitis. The purpose of this study was to evaluate the inhibitory effects of (S)-ketoprofen on experimentally induced alveolar bone loss in beagle dogs. 16, 18-month-old, female beagles were brought to optimal periodontal health over a 2-week pretreatment period. Experimental periodontitis was then induced by placing silk ligatures around premolar and molar teeth and by instituting a soft, plaque-promoting diet. At baseline, animals were randomized to 1 of 4 groups, consisting of 2x daily administration of (1) placebo dentifrice. (2) 0.3% (S)-ketoprofen dentifrice. (3) 3.0% (S)-ketoprofen dentifrice, or (4) 10.0 mg (S)-ketoprofen capsules (p.o.) over a 60 day treatment period. Standardized, periapical radiographs exposed at days 1 and 60 were analyzed by computer-assisted digital radiography in order to assess the rate of alveolar bone loss. Secondary outcomes included technetium 99m-tin-diphosphonate (99mTc-Sn-MDP) uptake and the gingival index. At baseline, no differences were observed among the groups for linear bone height or 99mTc-Sn-MDP uptake ratios. From days I to 60, cohorts differed significantly in terms of bone loss rates (p〈0.001). In particular, beagles treated with systemic or topical (S)-ketoprofen (0.3% or 3.0% dentifrices) exhibited significantly lower mean rates of bone loss compared to placebo treated beagles (p〈0.05). Group differences in mean radiopharmaceutical uptake ratio changes approached significance (ANOVA. p=0.07), where animals treated with topical 03% (S)-ketoprofen demonstrated a reduction and other groups demonstrated elevations over the 60-day dosing period. Treatment cohorts did differ significantly with respect to changes in mean gingival indices (p〈0.05). Animals treated with 0.3% or 3.0% (S)-ketoprofen dentifrice exhibited significantly reduced elevations in gingival index scores as compared to placebo treated animals. These data provide evidence that enantiospecific therapy with (S)-ketoprofen. topically or systemically delivered, may alter the progression of periodontal disease in the beagle dog model.

Electronic Resource

0017-789X

General, Interdisciplinary