Search Results - (Author, Cooperation:C. Stanton)

2018-03-06

Hindawi

0962-9351

1466-1861

Medicine

2012-10-09

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; DNA-Binding Proteins/metabolism ; Directed Molecular Evolution ; Escherichia coli/*cytology/*genetics ; *Gene Expression Regulation, Bacterial ; Genomic Islands/genetics ; *Logic ; *Models, Genetic ; Molecular Chaperones/metabolism ; Molecular Sequence Data ; Promoter Regions, Genetic/genetics ; Pseudomonas/genetics ; Salmonella/genetics ; Shigella/genetics ; Single-Cell Analysis ; Synthetic Biology ; Transcription Factors/metabolism ; Transcription, Genetic

2012-07-17

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aged ; Aged, 80 and over ; Aging/*physiology ; Cohort Studies ; Diet/*statistics & numerical data ; Diet Surveys ; Feces/*microbiology ; Fruit ; Geriatric Assessment ; Health ; *Health Status ; Health Surveys ; Homes for the Aged ; Hospitals, Community ; Humans ; Intestines/*microbiology ; Meat ; Metagenome/*physiology ; Rehabilitation Centers ; Surveys and Questionnaires ; Vegetables

1476-4687

Nature Archives 1869 - 2009

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

[Auszug] THE leading article entitled “Ottawa and After”, in NATURE of October 8, 1932, concludes with an interesting comment on higher education in the Dominions. I can speak with first-hand knowledge of conditions in New Zealand and Australia, and feel that there is a greater fundamental difficulty ...

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

We have measured the rate constant for the reaction of BO with H2 between 690 and 1030 K. The results are compared to transition-state-theory calculations consistent with a revised value for the heat of formation of the product HBO. By scaling the frequency of the doubly degenerate bend of the HHBO transition state in analogy with the isoelectronic HHCN transition state and lowering the calculated barrier from 9.5 to 8.5 kcal/mol, we are able to bring the theoretical and experimental rate constants into excellent agreement. Over the temperature range 300–3000 K, the theoretical rate constant is well represented by k(T)=7.49×10−23 cm3 s−1 T3.53 exp(−1590/T).

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We present an analysis of several of the factors that contribute to experimentally measured pump-probe spectra. We point out that for a correct description of the carrier generation, a full quantum mechanical description is essential. In addition, we discuss the regimes where the quantum mechanical description based on the Bloch equations can be replaced by a simplified semiclassical approach. We also demonstrate that the detection of nonequilibrium carrier distributions with the probe pulse is a nontrivial process due to quantum effects, and derive expressions for the detected signal for different experimental schemes. © 1996 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The measurement of quantum-size behavior in semiconductor crystals has been examined through an analysis of the size dependence of the semiconductor's absorption edge. In past studies, there appeared to be little agreement between theory and experiment for very small crystals. In this paper, the effects of crystal-size distribution and tunneling of the carrier wave functions into the quantum well barrier are considered. An analysis of the microstructure size and absorption edge of CdTe clusters in a glass matrix is conducted with samples ranging from 0.16 to 0.8 times the exciton Bohr diameter at the Γ point and from 1 to 5 times the exciton Bohr diameter at the L point. Results show fully coupled exciton behavior at the L point and a more complex process at the Γ point. In the latter, the band-gap energy increase with decreasing cluster size is significantly smaller than that calculated using a model in which the photoexcited carriers are assumed to be confined to a monosize set of clusters bounded by an infinite potential well. Analysis presented here shows that this discrepancy can be explained in part by inhomogeneous broadening of the absorptive transition and by carrier penetration into the insulator. The quantum-size behavior of CdTe crystals at the Γ point is subsequently found to follow fully decoupled carrier behavior modeled by Efros and Efros [Sov. Phys. Semicond. 16, 772 (1982)] when the inhomogeneous broadening and tunneling effects are taken into account.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Nonequilibrium electron and hole carrier dynamics are calculated for femtosecond photoexcitation in Ge using an ensemble Monte Carlo method. From the carrier distributions and k⋅p band-structure calculations, the time-dependent differential optical transmission that corresponds to pump-probe experiments is determined. It is found that electrons quickly scatter out of the optically coupled region and that the primary electron relaxation channel is from the Γ valley to the X valleys, then to the L valleys. Holes dominate the nonlinear absorption spectra in Ge. It is also found that light holes make a substantial contribution to the initial transient of the differential transmission, particularly for high-energy photoexcitation. © 1995 American Institute of Physics.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

We present results of ensemble Monte Carlo simulations of the room-temperature relaxation of nonthermal photoexcited electrons in GaAs quantum-well structures. Electrons are excited at a mean energy of 20 meV above the band edge, similar to the experiments of Knox et al. [Phys. Rev. Lett. 56, 1191 (1986)] and Oudar et al. [Phys. Rev. Lett. 55, 2075 (1985)]. Since this energy is less than the optical-phonon emission threshold, energy relaxation occurs primarily via carrier-carrier scatterings. We find that the excited electrons thermalize with the background electrons within 200 fs, in agreement with experiment.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

We model time-resolved photoluminescence in GaAs using an ensemble Monte Carlo method coupled with a k⋅p calculation of the band structure. We show that on a picosecond scale, carrier diffusion perpendicular to the layer significantly reduces the density at the surface and consequently has a first-order effect on luminescence measurements. To illustrate this we compare the calculated luminescence, with and without diffusion, to experimental data.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

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

Process Engineering, Biotechnology, Nutrition Technology

The influence of animal feed quality on lipid and cholesterol oxidation in whole milk powder was investigated. Powders from a herd receiving a ‘supplemented’ diet showed reduced PV (p 〈 0.01) and TBARS (p 〈 0.09) compared to a ‘restricted’ herd, after storage in both vacuum and sachet-packs and less (p 〈 0.003) cholesterol oxidation products (COPs). High pre-heating temperatures resulted in higher levels of PV, TBARS and COPs in fresh whole milk powders than low pre-heat temperatures, but after storage the reverse occurred. Superior animal feed quality and proper control of processing and storage conditions enhanced oxidative stability of whole milk powder. Lipid and cholesterol oxidation were positively correlated (p 〈 0.001).

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Rate constants have been measured for the reactions of boron atoms with a series of halomethanes. The experiments were performed in a linear flow tube apparatus at 300 K. The measured rate constants in units of cm3 molecule−1 s−1 are CCl4:9.5×10−11; CCl3H:4.8×10−11; CCl2H2:6.2×10−11; CClH3:1.4×10−11; CCl3F:3.1×10−11; CCl2F2:5.5×10−12; CClF3:1.7×10−13; CF4:〈3×10−14; CF3H:〈2×10−14. The reaction of boron with all the chloromethanes is facile. The chlorofluoromethanes present a more complex pattern. Noteworthy is the low reactivity of the channel to produce BF, furthermore, the presence of fluorine in the halomethanes reduces the reactivity at the chlorine site. Semiempirical MNDO calculations were performed on the reacting systems. These calculations suggest possible explanations for the observed results.

Electronic Resource

1750-3841

Blackwell Publishing Journal Backfiles 1879-2005

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

Process Engineering, Biotechnology, Nutrition Technology

The effects of grass dry matter (DM) allowance and dietary supplements of full fat rapeseeds on levels of cis-9,trans-11 octadecadienoic (CLA) acid in bovine milk were investigated. Grass allowance of 16 kg/(cow*day) resulted in reduced (p〈0.05) milk fat CLA levels (3.91 mg CLA/g fat) compared to 20 kg/(cow*day) after 19 wk treatment. CLA levels increased in milk fat from cows on a high-rapeseed-supplemented diet (p〈0.001) (1650 g/(cow*day) full fat rapeseed) compared to the control (pasture) and low rapeseed (p〈0.01) (825 g/(cow*day) full fat rapeseed) supplemented diets. The variation in milk fat CLA levels among individual cows over both trials was 1.5–16 mg/g.

Electronic Resource

0309-1740

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

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

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

0309-1740

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

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

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

0309-1740

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

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

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

0309-1740

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

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

Process Engineering, Biotechnology, Nutrition Technology

Electronic Resource

1438-2385

Key words Wheat ; Dough ; Bread ; Sodium caseinate ; Casein hydrolysate

Springer Online Journal Archives 1860-2000

Process Engineering, Biotechnology, Nutrition Technology

Abstract  Dairy ingredients are used in breadmaking for their nutritional benefits and functional properties. The effects of the traditionally-used whole and skimmed milk powder, sodium caseinate, casein hydrolysate and three whey protein concentrates on dough rheology and bread quality were studied. Whole and skimmed milk powders improved sensory characteristics. Sodium caseinate and hydrolysed casein displayed beneficial functional properties in breadmaking including low proof time, high volume and low firmness. Both ingredients increased dough height measured with the rheofermentometer. Bread with 2% or 4% sodium caseinate added was rated highly in sensory evaluation. Incorporation of whey protein concentrates generally increased proof time, decreased loaf volume and decreased dough height measured with the rheofermentometer.

Electronic Resource

1476-5535

Sterilization ; Bioreactor ; Computer ; F 0 ; Voice synthesizer ; Thermal input

Springer Online Journal Archives 1860-2000

Biology

Process Engineering, Biotechnology, Nutrition Technology

Summary Industrial fermentation media are normally sterilized with steam to destroy the indigenous microbial population prior to inoculation with a specific microorganism. Because biological validation of each sterilization cycle is impractical, an ‘overkill’ approach is commonly employed on the basis that alteration of heat-sensitive nutrients is less detrimental than survival of indigenous microbes. However, the heat destruction of microbes is known to be a probability function amenable to calculation. A computer has been programmed to calculate the on-line heat input asF 0 values during sterilization of media in stirred bioreactors. The accumulation ofF 0 values is then announced verbally to bioreactor operators by a communications controller with voice synthesizer.

Electronic Resource

0392-6737

Optical transient phenomena (including quantum beats, dephasings and revivals, photon echoes, free induction decay, and optical mutation) ; Excitons and related phenomena (including electron-hole drops) ; Electron states in low-dimensional structures (including quantum wells, superlattices, layer structures, and intercalation compounds) ; Weak localization effects (e.g., quantized states) ; Conference proceedings

Springer Online Journal Archives 1860-2000

Physics

Summary The optical properties of multiple quantum wells in the transition from isolated wells to a superlattice are investigated theoretically and experimentally. For superlattices with a miniband width similar to the binding energy of the 2s exciton of the isolated quantum well we find an exciton state energetically between the 1s exciton state and the onset of the miniband absorption. We find this state to be an interwell exciton, with the electron confined to one well and the hole to the neighboring well. The interwell exciton resembles the first Wannier-Stark localized exciton of a biased superlattice. However, the localization in the present case is mediated by the Coulomb interaction of the electron and hole. The state has considerable oscillator strength and is observed experimentally in linear and nonlinear experiments.

Electronic Resource