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1.
The content of neuraminic acid (NA) of different developmental stages of trout eggs was determined.
1.  The total NA increases from about 13 g NA per egg (6–8 weeks before spawning) to 50 g directly before spawning until hatching.
2.  In freshly hatched fish larvae the NA-content is decreased to about 40 per cent as compared with stages before hatching.
3.  The ratio of bound to free NA decreases from values of about 13.5 (6–8 weeks before spawning) to 0.85–1.2 at the hatching-stage.
4.  The bound NA is almost entirely bound to sialo-glycoproteins.
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2.
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3.
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   

4.
1.  Transepithelial potential differences (PDte) and acidification rates of the bath chamber were measured on isolated perfused posterior gills of the fiddler crabUca tangeri adapted to dilute seawater.
2.  The PDte decreased to almost zero when Na+ was substituted by choline or when ouabain was added to the perfusion saline in high concentrations (10 mmol·l–1). Thus, the rheogenic NaCl-transport across the gill epithelium seems to be totally Na+-dependent.
3.  When Cl– was replaced by gluconate, a bath positive PDte occurred which was insensitive to ouabain. This PDte could also be observed when, in addition to Cl– removal, Na+ was replaced by TMA+.
4.  Bath acidification under normal conditions could be abolished by ouabain, indicating that there is H+ excretion via electrically silent Na+/H+ exchange. In contrast, bath acidification under Cl–-free conditions is only partially blocked by ouabain.
5.  It is concluded that under Cl–-free conditions a rheogenic H+-pump in the apical membrane is responsible for the ouabain-insensitive bath acidification as well as for the PDte.
Parts of this study had been published earlier in abstract form  相似文献   

5.
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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6.
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   

7.
1.  Paramecium bursaria was stimulated by a light spot of 10–15 m diameter, and the photosensitive site was searched by recording responses in swimming behavior and in membrane potential.
2.  Local stimulation to the anterior half of the cell caused an avoiding response.
3.  Stimulation to the cells deciliated by ethanol treatment elicited a depolarization of the membrane potential.
4.  Local stimulation to the anteroventral portion elicited a depolarization, but stimulation to the dorsal side induced no change in the membrane potential.
5.  The action spectrum of depolarization elicited by local stimulation to the anteroventral surface showed two main peaks at 420 nm and 560 nm, corresponding to those of light stimulation of the whole cell.
6.  It is concluded that a photosensitive site exists on the anteroventral surface ofParamecium, in particular within the oral groove of the cell. This local photosensitivity is discussed with respect to the mating reaction.
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8.
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9.
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   

10.
1.  Non-visual sensory systems are likely to be important in antarctic fish since these fish inhabit an area where low light levels occur for long periods. This study was undertaken to examine the suitability of the lateral line system for prey detection.
2.  Recordings were made from afferent fibres of the anterior lateral line in the antarctic fishPagothenia borchgrevinki.
3.  A vibrating probe was used to stimulate the lateral line at a range of frequencies between 10 and 100 Hz.
4.  Most units responded best at a stimulus frequency of 40 Hz. Below the best frequency the response typically declined steeply and at higher frequencies it was usually better sustained.
5.  Crustacea identified as major components of the diet ofPagothenia borchgrevinki were individually attached to a force transducer to determine the vibrations produced by swimming movements.
6.  The Fourier amplitude spectra of swimming crustaceans exhibited prominent low frequency peaks at 3–6 Hz and higher frequency peaks in the 30–40 Hz range.
7.  It is concluded that the overlap in the frequency response characteristics of the anterior lateral line and the frequencies produced by crustacean prey clearly establishes the suitability of the lateral line for prey detection.
8.  In several instances recordings were made from fish primary afferent neurons responding to a swimming amphipod. These recordings confirm that crustacean swimming is indeed a potent natural stimulus of the lateral line system.
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11.
We have identified a nerve carrying auditory afferents and characterized their physiological responses in the tiger beetle,Cicindela marutha.
1.  The tympana are located at the lateral margins of the first abdominal tergum. The nerve carrying the tympanal afferents is a branch of the dorsal root from the first abdominal ganglion.
2.  Both male and female auditory afferent responses are sharply tuned to 30 kHz with sensitivities of 50–55 dB SPL.
3.  The auditory afferents show little adaptation and accurately code the temporal characteristics of the stimulus with the limit of a resolution of 6–10 ms.
4.  The difference in threshold between contralateral and ipsilateral afferents for lateral stimuli is greatest at 30 kHz and is at least 10–15 dB.
5.  Ablation studies indicate that the floppy membrane in the anterolateral corner of the tympanum is crucial for transduction while the medial portion of the tympanum is less important.
6.  The tiger beetle and acridid (locust and grasshopper) ears have evolved independently from homologous peripheral structures. The neural precursor of the tympanal organs in both animals is likely the pleural chordotonal organ of the first abdominal segment.
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12.
1.  In this commentary we discuss results obtained by a micromethod for the study of Cl– permeability across single nerve membranes from rabbit Deiters' neurons.
2.  These results showed the presence of GABAA receptors on the nerve cell membrane cytoplasmic side.
3.  We could show that these receptor complexes have a higher affinity for GABA than their extracellularly facing counterparts. Moreover, they present a phenomenon of desensitization. Another distinct property is that upon activation by GABA, they expose positive charges at their cytoplasmic mouths.
4.  We propose that these receptor complexes could functionin situ as a device for extruding Cl– anions from the nerve cell interior. This phenomenon would create an electrochemical gradient for Cl– penetration into the cell upon the action of extracellular GABA, after its presynaptic release.
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13.
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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14.
Artificial magnetic fields (MF) influence physiological processes in bees.
1.  An inhomogeneous, static magnetic field (IMF) reduces the flying activity of bees and increases their life span by more than 60%.
2.  The content of the ageing pigment lipofuscin in brain and, to a lesser extent, in thorax muscles increases with the physiological age. The content of lipofuscin of the thorax muscle is only 1/5 that of the brain.
3.  Despite their increased chronological age (60–74%) brain lipofuscin of bees under conditions of an inhomogeneous, static magnetic field is slightly reduced compared with bees in natural earth's magnetic field (EMF) conditions. No effects could be registered in the muscle lipofuscin of the thorax.
4.  There was no correlation between the content of lipofuscin and the chronological age.
5.  Flying activity is also reduced by horizontal magnetic fields (0.40–1.45 Oe).
6.  Dance tempo is reduced in compensated EMF and amplified static magnetic fields (0.84 Oe). Dance tempo is drastically reduced if compensation of the EMF is followed by application of a 5 Hz magnetic field with 1.04 Oepp, directed E-W.
Dedicated to Prof. Dr. Drs. h.c. M. Lindauer on the occasion of his 70th birthday  相似文献   

15.
The present review describes the effects of light on reproductive processes in fungi, mainly when action spectra are available.The study of these has resulted in three kinds of photoresponses observable in fungi:
–  responses only to UV light (230–380 nm)
–  responses to NUV and blue light (300–520nm)
–  responses to great wavelengths of the visible spectrum. The photomorphogenetic processes on the control of these same photoreceptor pigments are reviewed.
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16.
Summary  On Kos island, Greece, along an investigated coastal segment 3 km in length, four adjacent sectors were distinguished, (1) Empros beach, a rocky shore with plunging cliffs and a steeply dipping, submarine talus, (2) Thermi beach, a „coarse-clastic beach” with a subaerial cliff fringed by a bouldery to coarse gravelly beach with poorly developed zonation, (3) Dimitra beach, a gravelly beach with well-developed zonation, and (4) Phokas beach, a gravelly beach characterized by finer mean grain size. The lateral variation in Holocene coastal morphology would lead to different transgressive records: „rapid” sea-level rise that may be suggested by transgression of the rocky shore is contemporaneous with „gradual” rise recorded by transgression of the gravelly beaches. Dimitra beach is an about 500 m long, cuspate, microtidal, wave-dominated gravelly beach. From land offshore, in its fairweather configuration it shows
(a)  a backshore of rounded gravels to small, rounded boulders,
(b)  a winter storm berm paved by disc-shaped clasts,
(c)  a belt of beach cusps each centered by an oblique-triangular foreshore sand flat, and flanked by gravel ridges of roughly triangular shape in plan view,
(d)  a fairweather plunge step,
(e)  a. „relic storm/swell beachface” (uppermost shoreface during fairweather) of clean, rounded coarse gravels to cobbles,
(f)  a storm/swell plunge step, and
(g)  a vencer of gravels to boulders that, farther seaward, grades into submarine sand flats.
During storm upbuilding, the foreshore sand flats disappeared, the gravel ridges were eroded and an even, more gently dipping storm beachface developed. Beach restoration in a swell regime proceeded in feedback with the emergent fairweather beach morphology. During ensuing fairweather, the foreshore sand flats were partly winnowed. On Dimitra beach the layer involved in beach face to uppermost shoreface dynamics was about 1 m thick and 10–15 m wide. In fossil gravelly beach successions, features formed during highenergy events include both berms and master bedding surfaces. Features of the waning stage are fairweather plunge steps and relic storm/swell beachfaces (lower beachface). From cuspate gravel ridges of the upper beachface probably only the basal part is preserved.  相似文献   

17.
Oncostatin M, a multifunctional cytokine   总被引：6，自引：0，他引：6  
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18.
1.  The diffusive hydrogen conductance of chicken eggshell compound membrane was measured in situ on day 16 of incubation, in a direction parallel to the shell and the chorioallantois (lateral conductance). A value of 3.9 mmol d–1 kPa–1 was obtained through a ring 13.29 cm in circumference, 0.0076 cm thick and 0.3 cm long.
2.  Lateral hydrogen conductance for 1 mm2 of shell membrane 76 m thick is 30 times the conductance of one pore serving the same area.
3.  Lateral conductance for H2 is not significantly influenced by chorioallantoic perfusion.
4.  Oxygen consumption change due to partial covering of the hen eggshell indicates that there is a significant resistance to lateral diffusion of oxygen under the shell toward the covered area.
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19.
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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20.
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   

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