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1.
Müller  D. G.  Frenzer  K. 《Hydrobiologia》1993,(1):37-44
Culture studies with healthy and virus-infected isolates of Ectocarpus siliculosus, Feldmannia simplex and F. irregularis gave the following results:
–  Virus particles are produced in deformed reproductive organs (sporangia or gametangia) of the hosts and are released into the surrounding seawater.
–  Their infective potential is lost after several days of storage under laboratory conditions.
–  New infections occur when gametes or spores of the host get in contact with virus particles. The virus genome enters all cells of the developing new plant via mitosis.
–  Virus expression is variable, and in many cases the viability of the host is not impaired. Infected host plants may be partly fertile and pass the infection to their daughter plants.
–  Meiosis of the host can eliminate the virus genome and generate healthy progeny.
–  The genome of the Ectocarpus virus consists of dsDNA. Meiotic segregation patterns suggest an intimate association between virus genome and host chromosomes.
–  An extra-generic host range has been demonstrated for the Ectocarpus virus.
–  Field observations suggest that virus infections in ectocarpalean algae occur on all coasts of the world, and many or all Ectocarpus and Feldmannia populations are subject to contact with virus genomes.
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2.
G. Rombi  G. Piu  S. Piro  V. Anedda 《Cytotechnology》1993,11(Z1):S147-S149
Being able to carry zidovudine (AZT) at known concentrations into CD4+/CD38+ and CD14+ cells permits:
–  - to reduce the drug dosage and to increase the interval for administration (until 1 dose I.V. every week);
–  - to modulate the drug concentration into the CD4+/CD38 an CD14+ cells in relation to the in vitro determined HIV sensitiveness;
–  - to eliminate haematological, medullary and general toxicity;
–  - to be able to treat severely hill patients.
Further studies are necessary in order to:
–  - To find out the better phase to start the therapy;
–  - To use several drugs with different mechanisms of action in order to slow down as much as possible the presence of resistant viral strains.
–  - As for other drugs which are beginning to be used with artificial vehicles, futher studies are required to improve the selectivity and safety of LIPOAZT for the target cells including macrophages.
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3.
Twelve of the main European LCA software packages currently available are examined wirh the aim of establishing which are the most appropriate for LCAs on industrial processes. The packages performances are assessed in terms of
–  • Volume of Data
–  • WindowsTM environment
–  • Network Capabilities
–  • Impact Assessment
–  • Graphical representation of the inventory results
–  • Sensitivity analysis
–  • Units
–  • Cost
–  • User Support
–  • Flow Diagrams
–  • Burdens allocation
–  • Transparency of data
–  • Input & output parameters
–  • Demo version
–  • Quality of data
The review concludes with a Specification Table which summarises the facilities available on each software package. The general conclusion from this study is that for industrially based LCAs, there are four packages which may offer advantages over the rest. These are The Boustead Model, The Ecobilan Group’s TEAM™, PEMS 3.0 and SimaPro 3.1.  相似文献   

4.
J. Robb 《Human Evolution》1994,9(3):215-229
In recent years anthropologists have made much progress in understanding ancient activities from skeletal remains. In this paper, material from the Iron Age cemetery at Pontecagnano (VII-IV century BC) is used to illustrate activity-related traits of eight basic categories:
(1)  idiosyncratic patterns of dental wear
(2)  activity-related articular degeneration
(3)  non-pathological functional alterations (neoformations, contact facets)
(4)  mechanical remodelling of bone architecture
(5)  enthesopathies (muscular lesions)
(6)  traumatic lesions
(7)  activity-related pathologies
(8)  activity-related nutritional characteristics
These traits, and others, can be used not only singly but in conjunction to define (a) patterns of activity and occupational specialization for individuals, and (b) distributions within society reflecting the basic division of labor by geneder and class.  相似文献   

5.
Conclusions  
(1)  The aminoesters inhibit glucose-stimulated proton extrusion by yeast cells.
(2)  The inhibitory activity depends on aliphatic carbon chain length.
(3)  The inhibition of proton extrusion is concentration-dependent.
(4)  The aminoesters stimulate quinacrine accumulation in vacuoles of yeast cells so they should possess affinities for lysosomes.
This work was supported byKBN grant no. 7 A203 013 07.  相似文献   

6.
Oncostatin M, a multifunctional cytokine   总被引：6，自引：0，他引：6  
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7.
3DFS is a 3D flexible searching system for lead discovery. Version 1.0 of 3DFS was published recently (Wang, T.; Zhou, J. J. Chem. Inf. Comput. Sci., 1998, 38, 71–77). Here version 1.2 represents a substantial improvement over version 1.0. There are six major changes in version 1.2 compared to version 1.0.
1.  A new rule of aromatic ring recognition.
2.  The inclusion of multiple-type atoms and chains in queries.
3.  The inclusion of more spatial constraints, especially the directions of lone pairs.
4.  The improvement of the query file format.
5.  The addition of genetic search for flexible search.
6.  An output option for generating MOLfiles of hits.
Besides the above, this paper supplies:
1.  More query examples.
2.  A comparison between genetic search and Powell optimization.
3.  More detailed comparison between 3DFS and Chem-X.
4.  A preliminary application of 3DFS to K+ channel opener studies.
Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s0089490050231  相似文献   

8.
1.  The dependence of dark-adapted fly (Calliphora vicina) photoreceptors on oxygen was investigated by measuring the electroretinogram (ERG), the receptor potential, and the redox states of the mitochondrial cytochromes. The redox states were determined via reflection microspectrophotometry on white-eyed fly mutants.
2.  The light sensitivity of the photoreceptors at oxygen fractions above 2% is identical to that in the normal (air) environment, as judged from both ERG and receptor potential. Light sensitivity is rather abruptly and strongly reduced at oxygen fractions lower than 1% and vanishes at anoxia (0%).
3.  The redox state of the mitochondrial cytochromes also changes around oxygen fractions of 1–2%, but the dependence on oxygen fraction is less abrupt than that of ERG and receptor potential.
4.  The mitochondrial activity of dark-adapted fly photoreceptors appears to be well-buffered, to warrant ample supply of metabolic energy for unimpaired photoreceptor function down to extremely low oxygen levels.
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9.
1.  At 28°C conversion efficiency of total nitrogen (TN) was inversely related to size.
2.  In the pre-adult stage protein nitrogen (PN) conversion efficiency was high whereas in the Post-adult stage non-protein nitrogen (NPN) conversion efficiency was high.
3.  Lower temperature (20°C) was not congenial for PN conversion.
4.  Higher temperature favoured PN conversion for smaller fish but NPN for larger fish.
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10.
In the rift valley (North-East of France/South-West of Germany), the Rhine runs freely for 300 km from South to North. The absence of natural obstacles allows the development of a very regular profile of the river. We have therefore an opportunity to study very gradual modifications of the alluvial forest communities of the fluvial corridor from upstream to downstream, according to the gradual evolution of the ecological factors, related to slope decrease and hydrological modifications.We describe, from Basel to Mainz:
1)  modification of dynamic processes in the forest communities such as successional sequences or sylvigenetic mosaïcs of the terminal stages.
2)  modification of species richness.
3)  reduction of species diversity.
4)  simplification of the forest stratification.
5)  modification of efficiency of the biogeochemical cycling.
6)  ecological vicariances.
7)  modification in species behaviour.
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11.
1.  The overall rate of feeding at 28°C bears an inverse relationship to size; the time course of feeding appears to be size-independent and shows a decline with increase in time.
2.  Absorption efficiency is independent of size.
3.  The rates of absorption and conversion and conversion efficiency are inversely related to size.
4.  The rate of feeding is reflected on the rates of absorption and conversion.
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12.
1.  The activities of glycolytic enzymes and of related enzymes of anaerobic carbohydrate metabolism were determined inTubifex. The complete line of glycolytic enzymes was detected (Table 1). Only very little lactate dehydrogenase activity could be detected, while high activities of enzymes essential for the production of alanine and succinate are present.
2.  Under anaerobic conditions, lactate, alanine, succinate and volatile fatty acids are formed from14C-labeled glucose (Tables 2 and 3).
3.  Glycogen degradation was measured under anaerobic conditions (Fig. 1).
4.  During anaerobiosis a significant increase of alanine, succinate, propionate and acetate was found. However, the concentration of lactate increased only slightly. After an initial increase within the first 24 h of anaerobiosis, the concentration of alanine remained constant. Succinate, on the other hand, accumulated continuously during 48 h of anaerobiosis, reaching concentrations of 150 mol/g dry weight (Table 4, Fig. 2).
5.  The major end products of fermentation were identified as propionate and acetate. Both are excreted in substantial amounts (Table 5).
6.  The amount of anaerobic end products equals the amount of glycogen metabolized (Table 6).
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13.
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14.
1.  Inhibitory postsynaptic potentials (ipsps) produced by two classes of interneurons, CC (contralateral and caudal projecting) and lateral interneurons, were tested for strychnine sensitivity using paired intracellular recordings in the lamprey spinal cord. The ipsps were partially blocked by 0.2–0.5 M strychnine and were completely blocked by 5 M strychnine. Thus, the ipsps may be glycinergic.
2.  These interneurons are key participants in a proposed circuit model for fictive swimming. A connectionisttype computer simulation of the model demonstrated that the cycle period of the network increased with decreasing ipsp strength.
3.  Application of strychnine (0.1–0.5 M) to the spinal cord during fictive swimming induced by an excitatory amino acid increased cycle period, consistent with previous reports, but at odds with stimulation predictions.
4.  Strychnine also produced slow rhythmic modulation of fictive swimming (period = 12 s) which maintained left-right alternation and rostral-caudal coordination. Auto- and cross-correlation analyses revealed that the slow modulation was present in a weaker form in most control preparations during fictive swimming.
5.  Since the proposed model for the swimming pattern generator in the lamprey spinal cord does not predict the observed speeding with strychnine, nor the slow modulatory rhythm, it appears to be deficient in its present formulation.
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15.
1.  Direct contact between intra-epithelial nerve endings and ciliated cells was observed in frog (Rana pipiens) palate epithelium.
2.  Electrical stimulation of the palatine nerve to the explant or the explant culture induced an increase in ciliary beat frequency in explant and outgrowth cells.
3.  Atropine inhibited electrically stimulated ciliary beat frequency increase in the explant and outgrowth cells.
4.  Gap junctional intercellular communication appears to be involved in the propagation of stimulated ciliary beat frequency increase from innervated to non-innervated ciliated cells.
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16.
1.  The reactions of tympanic nerve fibers ofLocusta migratoria were recorded by glass microelectrodes in the metathoracic ganglion.
2.  The units were classified by frequency-, intensity-, and directional characteristics as well as by their response pattern. The response to speciesspecific song is compared with the response to song ofEphippiger ephippiger.
3.  The physiological properties lead to a classification into three types of low-frequency neurons (characteristic frequency 3.5–4 kHz; 4kHz; 5.5–6 kHz) and one type of high-frequency neuron (12–20 kHz). This is similar to other species (Gray, 1960, Michelsen, 1971).
4.  Intensity-coding is done by sharp rising intensity characteristics and by different absolute thresholds of the units.
5.  There is a marked directional sensitivity with some differences between LF and HF units. In the low frequency range the tympanal organ seems to react as a pressure gradient receiver; for high frequencies another mechanism is discussed.
6.  No filtering of species-specific song takes place at the level of the receptor cells.
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17.
1.  In the tortoise the capability of the spinal cord of generating rhythmic motor activity and of modulating reflex transmission depending on the motor cycle was investigated.
2.  In the intact animal co-ordinated locomotion was only observed if the feet had ground contact. Without ground contact only rhythmic struggling movements occurred. After spinalization some peripheral input was needed to initiate and sustain struggling movements in the air; the pattern of the movements was changed but not the frequency. After paralyzation the capability of generating a rhythmic activity was distinctly depressed in the spinal tortoise. The frequency of a rhythmic activity which could be induced in such a preparation by peripheral stimulation was very low, even after premedication with nialamide and DOPA.
3.  In the spinal paralyzed preparation during rhythmic motor activity a modulation of the membrane potential of motoneurones occurred with phases of depolarization and hyperpolarization. The latter at least partly were due to synaptic inhibition.
4.  In the spinal paralyzed preparation the transmission in excitatory reflex pathways from peripheral flexor reflex afferents (FRA) to motoneurones was phasically modulated during rhythmic motor activity in the way that the transmission was facilitated during the active phase of a motoneurone pool and inhibited during the reciprocal phase. In the inhibitory FRA pathways partly a particular kind of modulation of the transmission during the different phases was observed.
5.  The results indicate that the rhythmic motor activity in the spinal paralyzed tortoise which largely matched the activity found in cats, resembles in some aspects locomotor activity and therefore by analogy with findings in cats and turtles may be denoted as fictive locomotion.
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18.
Cannibalism in teleost fish   总被引：1，自引：0，他引：1  
1.  Cannibalistic behaviour in fish is reviewed here for the first time.
2.  Cannibalism has been recorded in 36 out of 410 teleost families according to the published literature, but is considered to be more widespread than this. Finding examples of cannibalism is not difficult, and it may be more interesting to look for taxa in which the behaviour does not take place.
3.  The families that have provided the most information include the Engraulididae, Esocidae, Poeciliidae, Gasterosteidae, Percidae and Cichlidae.
4.  Cannibalism has been classified into seven types, depending on life-history stage, age difference between cannibal and prey, and whether or not they are related.
5.  Although in captive populations, cannibalism tends to increase with increasing density and decreasing food availability, its role in population regulation has not been unequivocally demonstrated in any wild population, and obtaining the necessary data presents a formidable challenge to fish ecologists.
6.  Cannibalism is of some economic importance in aquaculture, but its impact can be reduced relatively easily, by frequent grading to reduce size variability.
7.  The main proximate advantage conferred by cannibalism is assumed to be nutritional. In an ultimate sense the behaviour may have evolved as a particularly effective competitive strategy.
8.  Finally, it is considered that cannibalism deserves more attention from fish biologists. Investigations, however, should recognize the different types of cannibalistic interaction, and, in particular, should explore the different implications of kin and nonkin cannibalism
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19.
1.  An extracellular recording and staining technique has been used to study the structure of individual ventral-cord elements in the auditory pathway ofLocusta migratoria.
2.  Three groups of auditory ventral-cord neurons can be distinguished: (a) neurons ascending to the supraesophageal ganglion, (b) T-shaped neurons, and (c) neurons limited to the thoracic ventral cord.
3.  The ventral-cord neurons ascending to the supraesophageal ganglion link the auditory centers of the thorax to those of the supraesophageal ganglion. These are, at least in part, richly arborized neurons of large diameter.
4.  The ventral-cord neurons with T structure send equivalent signals along both arms of the T; they resemble the neurons of the first group in that they make synaptic connections in the supraesophageal ganglion, but they also conduct auditory information to caudal regions of the thorax via the descending trunk of the axon.
5.  In the supraesophageal ganglion there are several extensive projection areas of the auditory ventral-cord neurons. No direct connections to the mushroom bodies, the central body or the protocerebral bridge could be demonstrated.
6.  The thoracic ventral-cord neurons act as short segmental interneurons, providing a connection between the tympanal receptor fibers and the ascending and T-shaped ventral-cord neurons. They play a crucial role in auditory information processing.
7.  The possible functional properties of the various morphological sections of the auditory ventral-cord neurons are discussed, with reference to their connections with motor and other neuronal systems.
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20.
1.  Seasonal changes in the half-times (0.5) for calcium influx and outflux in bone, skin and scales, and soft-tissue compartments ofF. kansae were measured.
2.  The size of diffusible calcium pools in the three compartments was estimated from the ratio of the loading and unloading half-times. Both the bone and skin and scales compartments contain diffusible calcium pools which increase in size during the summer months.
3.  The calcium in the soft-tissue compartment is all diffusible, and the kinetics indicate that this compartment receives calcium from the other two compartments.
4.  Hypophysectomy reduced the rate of calcium turnover in summer animals to the levels measured in intact winter animals. Such treatment also affected the distribution of radiocalcium within the animal.
5.  It is concluded that acellular bone is a metabolically active tissue.
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