ALBERT

Notes: More than 50 feedstuffs used or of potential use in diets for rainbow trout Oncorhyndus mykiss were compared through metabolism chamber trials. Testing included determination of apparent digestibility and metabolic energy for a wide variety of ingredients, including fish and animal meals, vegetable proteins, and single cell protein products. Testing involved feeding individual 200–300-g fish contained in replicate chambers, from which feces, urine, and gill excreta were collected seg arately and analyzed for residual nitrogen and energy. For comparison, several products previously tested at this or other laboratories were re-evaluated at dietary concentrations of 25, 50, or 100%.

Notes: We establish a new approach to calculating spectral statistics in disordered conductors, by considering how energy levels move in response to changes in the impurity potential. We use this fictitious dynamics to calculate the spectral form factor in two ways. First, describing the dynamics using a Fokker–Planck equation, we make a physically motivated decoupling, obtaining the spectral correlations in terms of the quantum return probability. Second, from an identity which we derive between two- and three-particle correlation functions, we make a mathematically controlled decoupling to obtain the same result. We also calculate weak localization corrections to this result, and show for two dimensional systems (which are of most interest) that corrections vanish to three-loop order. © 1996 American Institute of Physics.

Notes: Abstract Posttranslational modification of proteins by phosphorylation is a universal mechanism for regulating diverse biological functions. Recognition that many cellular proteins are reversibly phosphorylated in response to external stimuli or intracellular signals has generated an ongoing interest in identifying and characterizing plant protein kinases and protein phosphatases that modulate the phosphorylation status of proteins. This review discusses recent advances in our understanding of the structure, regulation, and function of plant protein phosphatases. Three major classes of enzymes have been reported in plants that are homologues of the mammalian type-1, -2A, and -2C protein serine/threonine phosphatases. Molecular genetic and biochemical studies reveal a role for some of these enzymes in signal transduction, cell cycle progression, and hormonal regulation. Studies also point to the presence of additional phosphatases in plants that are unrelated to these major classes.

Notes: [Auszug] Besides chemotaxis, C-X-C and C- C chemokines function as mediators in T-cell activation and in many lymphocyte biological responses. Detailed information about downstream signalling pathways is necessary to understand the role of chemokines in normal physiology and inflammation. We have built a ...

Notes: Pseudotsuga menziesii (Mirb.) Franco] plantation growing with volunteer red alder (Alnus rubra Bong.). Ten years earlier, the preceding mature conifer stand was clearcut and nearly all logging slash and forest floor were consumed by slash fire. Forest floor mass in the 9-yr-old plantation averaged 9.86 Mg ha-1, with 3.71 Mg C, 98.0 kg N, 10.6 kg P, and 8.4 kg S ha-1. Mineral soils to 1-m depth averaged 176 Mg C, 8330 kg N, 3340 kg P, and 605 kg S ha-1 in the 〈2-mm fraction. The 2- to 〈6-mm soils fraction averaged an additional 100 Mg C, 4480 kg N, and 1700 kg P ha-1. Net mineralizable N as NH4 (anaerobic N mineralization index) totaled 99 kg N ha-1 in the top 45 cm of the mineral soil and 62 kg N ha-1 in the 45- to 100-cm depth. Density fractionation showed that the light fraction (〈1.65 Mg m-3 ) was only 13.4% of the fine soil mass of the 0- to 15- cm depth, yet contained about 40% of the total C and N capital in the 〈2-mm size fraction. The substantial amounts of C and nutrients in this low-bulk density soil (〈2-mm fraction, 0.30 Mg m-3) indicate a fertile soil despite large previous losses of organic matter and N from the site.

Notes: [Auszug] Of the five known forms of mammalian FMO12, FMO3 represents the major hepatic FMO in humans9,10 and displays a distinct substrate preference for tertiary amines11. As TMA is cleared substantially by hepatic first-pass metabolism13, FMO3 is thus likely to catalyze most TMA N-oxidation in vivo. The ...

Notes: Abstract This paper uses a laboratory experimental setting to make observations about the iteration process in engineering design. Iteration is an important and ubiquitous feature of engineering design. Previous research has constructed prescriptive mathematical models of the iteration process in an attempt to aid the design manager. In this paper, experimental observations are made about design iteration in a group setting, and those observations are compared with the existing models of the iteration process. Some correspondence with existing models is noted, although there are also significant differences. These differences could be used to improve the mathematical models of the iteration process.

Notes: Abstract Objective. Our objective was to determine if rebreathing would reduce the gradient between arterial and end-tidal CO2 tension during positive-pressure ventilation.Methods. Design: Experimental investigation.Setting: Anesthesiology laboratory.Subjects: A total of 10 dogs of either sex.Interventions: Anesthesia (sodium pentobarbital) and muscle relaxation (pancuronium) were induced and animals were tracheally intubated and ventilated with a standard anesthesia ventilator and breathing circuit with CO2 absorber and then with a Mapleson D circuit with a fresh gas flow rate ( $$\dot V$$ f) equal to alveolar ventilation plus the sampling flow rate of two capnometers. Rebreathing was varied by adjusting the respiratory rate (RR) so that minute ventilation ( $$\dot V$$ e) to $$\dot V$$ f ratio was 1:1, 2:1, 3:1, and 4:1.Results. CO2 production (ATPD) was determined as the product of expired concentration of CO2 and $$\dot V$$ e (BTPS). Alveolar ventilation ( $$\dot V$$ a) was calculated by dividing the product of CO2 production and barometric pressure corrected for ambient temperature and water vapor pressure at body temperature by PaCO 2. Tidal volume, RR, airway gas temperature, concentration of CO2 in gas at the tracheal tube and inlet/outlet of the mechanical ventilator, body temperature, arterial gas tensions and pH, heart rate, arterial blood pressure, and cardiac output were measured. Minute ventilation, mean arterial blood pressure and end-expiratory CO2 tension (Péco 2)(BTPS) were calculated. During positive-pressure ventilation, concentration of inspired CO2 was zero with standard circuitry, and significantly increased with Mapleson D when $$\dot V$$ e: $$\dot V$$ f ratio was 1:1 (0.56±0.19%), 2:1 (1.97±1.30%), 3:1 (2.56±1.05%), and 4:1 (3.01±1.45%) (p〈0.05).Péco 2 was 34.8±3.2 mm Hg during ventilation with the standard circuit, and significantly increased during ventilation with Mapleson D when $$\dot V$$ e: $$\dot V$$ f ratio was increased from 1:1 (35.4±2.5 mm Hg) to 2:1 (40.2±3.6 mm Hg) and was not further increased at a $$\dot V$$ e: $$\dot V$$ f ratio of 3:1 (41.8±2.7 mm Hg) or 4:1 (41.3±2.4 mm Hg). The selected fresh gas flow rate was appropriate, because PaCO 2 remained unchanged regardless of $$\dot V$$ e: $$\dot V$$ f ratio, indicating PaCO 2 was dependent on $$\dot V$$ f, not on $$\dot V$$ e. The gradient between PaCO 2 andPéco 2 during ventilation with the standard circuit was 6.6±3.0 mm Hg; during ventilation with Mapleson D, it decreased significantly when $$\dot V$$ e: $$\dot V$$ f ratio was increased from 1:1 (6.5±3.6 mm Hg) to 2:1 (2.9±1.5 mm Hg), but was not significantly reduced further at 3:1 (1.7±1.1 mm Hg) or 4:1 (1.8±0.5 mm Hg) (p〈0.05).Conclusions. Rebreathing with a Mapleson D circuit and a $$\dot V$$ f equal to $$\dot V$$ a permitted normal CO2 elimination. ArterialPCO 2 toPéco 2 gradient decreased significantly during rebreathing, thus improving the reliability of capnography for estimating arterialPCO 2. Consideration should be given to using the Mapleson D as a rebreathing circuit.