Author Keywords: Rabbit; thermoregulation; infra-red; higher critical temperature 相似文献
The technique has been employed in the evaluation of mixed enzyme induction using phenobarbitone and β-naphthoflavone (benzoflavone). as a safe substitute for Aroclor-1254. The post-mitochondrial preparations from rats induced with the combined inducers had a similar “metabolic competence” to those derived from Aroclor induced animals. Such a combination would therefore provide a useful alternative to Aroclor-1254 for routine screening.
It was found that the level of “S9” present in the metabolic system greatly affected the quantitative mutagenic response. This varied considerably from chemical to chemical and underlined the need for such preliminary investigations in routine screening. 相似文献
2. This effect is decreased under phosphorylating conditions (presence of ADP, Pi, Mg2+), and completely inhibited by the uncoupler of phosphorylation NH4Cl (5–10 mM), as well as the ionophores nigericin and gramicidin-D (both at 5 · 10−8 M). The MgCl2 concentration dependence of the anthroyl stearate enhancement effect is identical to that previously observed for cyclic photophosphorylation, as well as for the formation of a “high energy intermediate”. The anthroyl stearate fluorescence enhancement is inhibited by increasing concentrations of ionophores in parallel with the decrease in ATP synthesis, but is essentially unaffected by specific inhibitors (Dio-9 and phlorizin) of photophosphorylation; thus, it appears that anthroyl stearate monitors a component of the “high energy state” of the thylakoid membrane rather than a terminal phosphorylation step.
3. The light-induced anthroyl stearate fluorescence enhancement is suggested to monitor a proton gradient in the energized chloroplast because (a) similar enhancement can be produced by sudden injection of hydrogen ions in a solution of anthroyl stearate; (b) when the proton gradient is dissipated by gramicidin or nigericin light-induced anthroyl stearate fluorescence is eliminated; (c) when the proton gradient is dissipated by tetraphenylboron, light-induced anthroyl stearate fluorescence decreases, and (d) light-induced anthroyl stearate fluorescence change as a function of pH is qualitatively similar to that observed with other probes for a proton gradient (e.g. 9-aminoacridine). Furthermore, anthroyl stearate does not monitor H+ uptake per se because (a) the pH dependence of H+ transport is different from that of the anthroyl stearate fluorescence change, and (b) tetraphenylboron, which does not inhibit H+ uptake, reduces anthroyl stearate fluorescence.
Thus, anthroyl stearate appears to be a useful probe of a proton gradient supported by phenazine methosulfate or Diquat catalyzed electron flow and is the first “non-amine” fluorescence probe utilized for this purpose in chloroplasts. 相似文献
In this paper we consider opposite problems connected with string non-inclusion relations: find the shortest string included in no string of a given finite language and find the longest string including no string of a given finite language. The predicate “string is not included in string β” is interpreted either as “ is not a subsequence of β” or as “ is not a substring of β”. The main purpose is to determine the complexity status of the non-similarity problems. Using graph approaches, we present NP-hardness proofs for the first interpretation and polynomial-time algorithms for the second one. Special cases of the problems, and related issues are discussed. 相似文献
1. 1.|An experiment was carried out to examine the effects of various levels of infra-red (i.r.) radiation on rectal temperature (RT) and respiration rate (RR) in New Zealand While rabbits.
2. 2.|A 4 × 3 × 6 factorial design was employed in which the factors were: four intensities of i.r. radiant heating of 0.0, 1.9, 2.1 and 2.4 MJ/m2/h, three replicates and six rabbits.
3. 3.|rectal temperature differed (P < 0.05) between treatments and were highest at the “high” level of i.r. radiation (1°C higher than for controls). At the “medium” and “low” levels of i.r. heating RTs were respectively 0.3 and 0.2°C higher than in controls.
4. 4.|At different levels of radiation RR were different (P < 0.05), with the highest (422.7 ± 218.1 breaths/min) at 2.4 MJ/m2/h i.r. radiant heating. This RR was almost 2.5 times that in controls, while at the “low” and “medium” i.r. levels RR values were respectively 1.5 and 2 times those of controls.
The initial water activity (aw) of the biocatalyst, POS and EPAX 2050TG concentrations, time and temperature showed a significant effect on the transesterification reaction, as well as on the competing reactions of hydrolysis and lipid oxidation.
Depending on the factors included, the transesterification reaction was described either by first- or second-order models.
The production of free fatty acids, which is ascribed both to the hydrolytic reaction and the mechanism of lipase-catalysed transesterification, showed a second-order dependence on the initial aw of the biocatalyst. 相似文献
- 1. 1. Features of life history strategies of Antarctic terrestrial invertebrates are reviewed and compared with the predictions of two widely-used general life history models.
- 2. 2. Many features observed are consistent with the predictions of “adversity-” or “stress-selected” life histories, although “ruderal” characteristics are also observed.
- 3. 3. Many features are plesiotypic for the taxonomic groups concerned, suggesting a lack of evolved adaptations within the Antarctic biota.
- 4. 4. A large degree of flexibility is found in the life histories; this flexibility itself may allow passage of environmentally-imposed selective filters limiting colonisation and development in isolated and extreme terrestrial habitats.
- 5. 5. In general, Antarctic terrestrial invertebrates may be regarded as pre-adapted for survival of the various stresses imposed by their extreme environment.
1. 1. We propose a hierarchical model as a hypothesis to evaluate comfort in lighting environments.
2. 2. The model consists of physical quantities such as stimuli, and visual sensations as the first response, and then overall evaluation.
3. 3. A pilot experiment in a side-lit classroom usng 147 subjects was made to examine this model.
4. 4. It was found that in the side-lit classroom the most effective answers for discrimination between “acceptable” and “not acceptable” were “the surface of desk was not considered dark” and “not to experience any reflectance of lighting on the sheet of paper on which they wrote”.
5. 5. Moreover all of the effective items relate to the task area, namely desk and blackboard, and this meant that subjects gave priority to workability in the classroom.
Author Keywords: Daylighting; luminous environment; subjective experiment; class-room 相似文献
The new species Bowmanites cupulatus is introduced to accommodate fructufications most probably belonging to Sphenophyllum miravallis.
S. crenulatum Knight ex Wagner is considered to be a heterotypic synonym of S. miravallis, the latter name having priority. 相似文献
1. 1. The sensitivity of serum enzyme levels as indicators of tissue damage is less well established in the prodromal period of heatstroke, especially for sub-lethal stress conditions.
2. 2. Anaesthetized rats were exposed to two different sets of thermal conditions.
3. 3. Plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase (CK) and lactate dehydrogenase (LD) were assayed in each group upon termination of stress, 6 h post-stress and 24 h post-stress.
4. 4. The tissue “damage” sustained was mild to moderate and completely reversible.
5. 5. The rate of rise in body temperature may constitute an important factor in the ultimate pathology.
6. 6. CK proved to be the most sensitive parameter of tissue “damage”.
Author Keywords: Prodromal phase of heatstroke; sub-lethal stress; anaesthetized rat model; plasma enzymes; tissue “amage”; rate of rise in body temperature 相似文献
In despite of the fruitful approach of Darwin, most of the brain scientists do prefer to analyze either one type of brain or even only one structure to interpret the brain function. The single neuron doctrine developed by Sherrington also did not consider these various aspects. The avenue opened by Hans Berger which introduced the analysis of the brain oscillations was an important step towards understanding of the “whole brain”.
In this report we aim to describe narratively, technical, strategical and philosophical steps to bridge “Sherrington Neuron Doctrine” with the “Neurons-Brain Theory” of the whole brain by means of the method developed by Hans Berger. 相似文献
The present results indicate that the “I1-imidazoline receptors” mediating effects of clonidine and moxonidine in PC12 and the transfected HEK293 cells belong to the S1P-receptor family; in particular, the data obtained in PC12 cells suggest that the I1 imidazoline receptors represent a mixture of S1P1- and S1P3-receptors and/or hetero-dimers of both. 相似文献
1. 1.|In 15 conscious Pekin ducks, 40 “warm sensitive” hypothalamic neurons were identified according to their discharge rates at 40°C Thy (F40), local temperature coefficients (Δ/ΔT) and Q10.
2. 2.|Q10 and either F40 or ΔF/ΔT were little or not related.
3. 3.|A positive correlation between F40 and ΔF/ΔT was observed which was particularly close (r = 0.94 and 0.96) when the neurons were classified according to their Q10 of <2 and >2.
4. 4.|The results suggest that neurons with positive temperature coefficients in the duck's hypothalamus mostly exhibit linear to exponential temperature-discharge relationships.
5. 5.|This is an contrast to observations on mammalian hypothalamic thermosensitive neurons and may relate to the absence of the thermosensory function in the duck's rostral brainstem.
Author Keywords: Neuronal thermosensitivity; hypothalamic thermosensory function; Temperature and synaptic transmission; avian thermoregulation; mammalian thermoregulation 相似文献
2. Growth of three “petite-negative” yeast species was arrested by a combined inhibition of respiration by antimycin A and of adenine nucleotide translocation by bongkrekic acid. Thus, the arrest of growth upon inhibition of adenine nucleotide translocation in non-respiring cells is not specific for ρ− mutants and may be a general characteristic of eucaryotic cells. 相似文献