scholarly journals HYDROGEOCHEMICAL CONDITION OF THE PIKROLIMNI LAKE (KILKIS GREECE)

2004 ◽  
Vol 36 (1) ◽  
pp. 192
Author(s):  
E. Dotsika ◽  
Y. Maniatis ◽  
E. Tzavidopoulos ◽  
D. Poutoukis ◽  
K. Albanakis
Keyword(s):  
Fresh Water ◽  
Major Ions ◽  
Salt Water ◽  
Field Measurements ◽  
The Other ◽  
Chemical Analyses ◽  
Temperature Conductivity ◽  
Analytical Scheme ◽  
Hydrochemical Data ◽  
High Degree

In order to understand the hydrogeochemical conditions of the basin of Pikrolimni we collected water samples from the borehole in the thermal spa of Pikrolimni and samples of brine and sediments from the lake. We also sampled fresh water of the region. The depth of the borehole in the thermal spa is approximately 250 meters. This water is naturally sparkling, with a metallic aftertaste and a slight organic smell. The samples were taken twice during the year: in summer (8/2002) and in winter (2003). The analytical scheme includes field measurements of temperature, conductivity and pH. Major ions (Na+, K+, Ca2+, Mg2\ CI", Br, S04 2", C03 2", HC03", N03"), F and Br were determined, in laboratory, according to standard analytical methods. Samples were also subjected to isotopie analysis of δ Ο and δ2Η. The results from the chemical analyses of the samples, show that the waters taken from the borehole, are of the type Mg- (Na-Ca)-HCC>3 and the salts of the lake are of the type Na-CI- (CO3-S04). The salts of the lake result from mixing and condensation of the waters which are accumulated in the basin of the lake, and come not only from sources that feed the lake, e.g. waters from borehole, but also from rain water. The waters of these sources are mainly of meteoritic origin and circulate deeply, mixing probably with salt water of deeper and probably of warmer horizons. The latter comes in agreement with the hydrothermal field, which exists in the area. From hydrochemical data, the brines of summer clearly correspond to waters, which have been submitted under high degree of evaporation: they are residual mother solutions before the step of the precipitation of halite. During winter, dilution of brines and dissolution of depositing minerals by fresh water are observed. On the other hand, evaporating conditions are created in the lake during summer.

Rheotaxis of Elvers of the American Eel (Anguilla rostrata) in the Laboratory to Water from Different Streams in Nova Scotia

1968 ◽  
Vol 25 (8) ◽  
pp. 1591-1602 ◽  
Author(s):  
S. G. Miles
Keyword(s):  
Organic Matter ◽  
Nova Scotia ◽  
Fresh Water ◽  
Stream Water ◽  
Salt Water ◽  
The Other ◽  
Anguilla Rostrata ◽  
American Eel ◽  
Heat Stable ◽  
Experimental Apparatus

In an experimental apparatus, elvers of the American eel (Anguilla rostrata) showed a stronger positive rheotaxis to fresh water than to salt water. The attractiveness of the fresh water was due to dissolved and particulate organic matter; these components were bio-degradable, heat stable, and nonvolatile. Four streams near Halifax, Nova Scotia, were tested, and were found to differ greatly in their attraction of elvers. Elvers were collected from each of three of these streams, and were not found to be attracted to their own stream water; elvers from one stream gave a greater rheotactic response than elvers from the other streams. The presence of adult eels in the water rendered it more attractive, whereas the presence of elvers made it less so.

On friction and surface cracking during sliding of ice on ice

2003 ◽  
Vol 49 (166) ◽  
pp. 391-396 ◽  
Author(s):  
Maurine Montagnat ◽  
Erland M. Schulson
Keyword(s):  
Fresh Water ◽  
Kinetic Coefficient ◽  
Salt Water ◽  
The Other ◽  
Surface Cracks ◽  
Experimental Conditions ◽  
Water Ice ◽  
Surface Cracking ◽  
Double Shear ◽  
Deformation Features

AbstractAs a complement to earlier measurements on the friction of both granular fresh-water ice and S2 columnar salt-water ice, new experiments were performed on the friction of S2 columnar fresh-water ice sliding against itself at low velocities (5 × 10−7 to 5 × 10−1 m s−1) and at −10°C, using the same double-shear device as was used earlier. The results showed that under a given set of experimental conditions the kinetic coefficient of friction of S2 fresh-water ice compares favorably with that of the other two variants.The experiments also revealed friction-induced surface cracks and recrystallized grains.These deformation features are explained, respectively, in terms of fracture mechanics and an earlier model of dynamic recrystallization in ice.

Survival of certain naturally acquired freshwater parasites of juvenile sockeye salmon, Oncorhynchus nerka (Walbaum), in hosts held in fresh and sea water, and implications for their use as population tags

1989 ◽  
Vol 67 (7) ◽  
pp. 1757-1766 ◽  
Author(s):  
R. E. Bailey ◽  
L. Margolis ◽  
G. D. Workman
Keyword(s):  
British Columbia ◽  
Fresh Water ◽  
Water Samples ◽  
Sockeye Salmon ◽  
Sea Water ◽  
Salt Water ◽  
Oncorhynchus Nerka ◽  
The Other ◽  
Maximum Life Span ◽  
Natural Tags

Sockeye salmon (Oncorhynchus nerka) smolts were captured from the outlet streams of Cultus Lake, British Columbia, in 1985 and 1986, and from Fraser Lake, British Columbia, in 1986. Samples collected in 1985 were reared in salt water. Samples collected from each lake in 1986 were divided equally into two groups: one group was reared in fresh water, the other was maintained in salt water. Initially biweekly, and later monthly, subsamples from each group were examined for seven parasite taxa: Myxidium salvelini, Diplostomulum sp. metacercaria, Phyllodistomum umblae, Eubothrium sp. (immature), Proteocephalus sp. (immature), Neoechinorhynchus salmonis, and Salmincola californiensis. The maximum life-span was greater than the duration of the experiments (32–40 weeks) for all species in hosts reared in fresh water (except for S. californiensis, which was removed from all freshwater hosts). Survival of M. salvelini, P. umblae, and S. californiensis was reduced in hosts reared in sea water. No differences in survival of each of Diplostomulum sp. metacercaria, Eubothrium sp., Proteocephalus sp., and N. salmonis were observed between hosts held in fresh water or salt water. Implications for the use of these parasites as natural tags are discussed.

C-Terminal amino acid sequence of chicken pepsinogen and its homology with sequences of other acid proteases

1980 ◽  
Vol 45 (4) ◽  
pp. 1144-1154 ◽  
Author(s):  
Miroslav Baudyš ◽  
Helena Keilová ◽  
Vladimír Kostka
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
The Other ◽  
Terminal Sequence ◽  
Terminal Part ◽  
Terminal Amino Acid ◽  
Tryptic Peptides ◽  
Terminal Amino ◽  
High Degree ◽  
Terminal Amino Acid Sequence

To determine the primary structure of the C-terminal part of the molecule of chicken pepsinogen the tryptic, chymotryptic and thermolytic digest of the protein were investigated and peptides derived from this region were sought. These peptides permitted the following 21-residue C-terminal sequence to be determined: ...Ile-Arg-Glu-Tyr-Tyr-Val-Ile-Phe-Asp-Arg-Ala-Asn-Asn-Lys-Val-Gly-Leu-Ser-Pro-Leu-Ser.COOH. A comparison of this structure with the C-terminal sequential regions of the other acid proteases shows a high degree of homology between chicken pepsinogen and these proteases (e.g., the degree of homology with respect to hog pepsinogen and calf prochymosin is about 66%). Additional tryptic peptides, derived from the N-terminal part of the zymogen molecule whose amino acid sequence has been reported before, were also obtained in this study. This sequence was extended by two residues using an overlapping peptide. An ancillary result of this study was the isolation of tryptic peptides derived from other regions of the zymogen molecule.

scholarly journals Development of a New Pasta Product by the Incorporation of Chestnut Flour and Bee Pollen

2021 ◽  
Vol 11 (14) ◽  
pp. 6617
Author(s):  
Maëlys Brochard ◽  
Paula Correia ◽  
Maria João Barroca ◽  
Raquel P. F. Guiné
Keyword(s):  
Wheat Flour ◽  
Nutritional Composition ◽  
Cooking Time ◽  
The Other ◽  
Physical Characterization ◽  
Chemical Analyses ◽  
High Fiber ◽  
Chestnut Flour ◽  
Cooking Yield

This work aimed at developing fortified pastas incorporating chestnut flour (25–55%) and powdered pollen (5–20%), either separately or in combination, as well as the characterization of the products obtained. To this, a physical characterization was carried out (analyzing texture and color), complemented with chemical analyses to determine the nutritional composition. Results showed that adding chestnut flour over 40% to wheat-flour pasta shortened optimum cooking time and lowered cooking yield, and the addition to pasta prepared with wheat flour and eggs maintained approximately constant the cooking yield. Additionally, the incorporation of pollen powder (up to 20%) in pasta prepared with wheat flour and water or fresh egg shortened the cooking time and cooking yield, in both fresh and dried pasta. The most suitable percentages of the new ingredients were 50% for chestnut and 10% for pollen. Comparing with the control pasta recipe (wheat flour and egg), the addition of chestnut flour (50%) or pollen powder (10%) increased stickiness, adhesiveness and the darkening of the final product (fresh or dried) but maintained the firmness of the pasta. The cooking of fresh or dried pasta enriched with both ingredients turned the pasta clearer and slightly stickier. On the other hand, the addition of chestnut flour and pollen powder in pasta formulation delivered a nutritionally balanced product with high fiber, vitamins and minerals. Overall, chestnut flour and powdered pollen represent promising ingredients for the development of functional fresh and dried pasta formulations.

scholarly journals Involvement of loop 5 lysine residues and the N-terminal β-hairpin of the ribotoxin hirsutellin A on its insecticidal activity

2016 ◽  
Vol 397 (2) ◽  
pp. 135-145 ◽  
Author(s):  
Miriam Olombrada ◽  
Lucía García-Ortega ◽  
Javier Lacadena ◽  
Mercedes Oñaderra ◽  
José G. Gavilanes ◽  
...  
Keyword(s):  
Active Sites ◽  
Structural Changes ◽  
The Other ◽  
Spatial Proximity ◽  
Ribonucleolytic Activity ◽  
The Family ◽  
Lysine Residues ◽  
Hirsutella Thompsonii ◽  
Close Spatial Proximity ◽  
High Degree

Abstract Ribotoxins are cytotoxic members of the family of fungal extracellular ribonucleases best represented by RNase T1. They share a high degree of sequence identity and a common structural fold, including the geometric arrangement of their active sites. However, ribotoxins are larger, with a well-defined N-terminal β-hairpin, and display longer and positively charged unstructured loops. These structural differences account for their cytotoxic properties. Unexpectedly, the discovery of hirsutellin A (HtA), a ribotoxin produced by the invertebrate pathogen Hirsutella thompsonii, showed how it was possible to accommodate these features into a shorter amino acid sequence. Examination of HtA N-terminal β-hairpin reveals differences in terms of length, charge, and spatial distribution. Consequently, four different HtA mutants were prepared and characterized. One of them was the result of deleting this hairpin [Δ(8-15)] while the other three affected single Lys residues in its close spatial proximity (K115E, K118E, and K123E). The results obtained support the general conclusion that HtA active site would show a high degree of plasticity, being able to accommodate electrostatic and structural changes not suitable for the other previously known larger ribotoxins, as the variants described here only presented small differences in terms of ribonucleolytic activity and cytotoxicity against cultured insect cells.

Methylene. III. Gas phase reactions with 1-chloropropane

1969 ◽  
Vol 312 (1509) ◽  
pp. 141-161 ◽  
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Hydrogen Abstraction ◽  
The Other ◽  
Gas Phase Reactions ◽  
Other Hand ◽  
Chlorine Substituent ◽  
High Degree ◽  
Singlet Methylene

The work described in this and the following paper is a continuation of that in parts I and II, devoted to elucidation of the mechanism of the reactions of methylene with chloroalkanes, with particular reference to the reactivities of singlet and triplet methylene in abstraction and insertion processes. The products of the reaction between methylene, prepared by the photolysis of ketene, and 1-chloropropane have been identified and estimated and their dependence on reactant pressures, photolysing wavelength and presence of foreign gases (oxygen and carbon mon­oxide) has been investigated. Both insertion and abstraction mechanisms contribute significantly to the over-all reaction, insertion being relatively much more important than with chloroethane. This type of process appears to be confined to singlet methylene. If, as seems likely, there is no insertion into C—Cl bonds under our conditions (see part IV), insertion into C2—H and C3—H bonds occurs in statistical ratio, approximately. On the other hand, the chlorine substituent reduces the probability of insertion into C—H bonds in its vicinity. As in the chloroethane system, both species of methylene show a high degree of selectivity in their abstraction reactions. We find that k S Cl / k S H >7.7, k T Cl / k T H < 0.14, where the k ’s are rate constants for abstraction, and the super- and subscripts indicate the species of methylene and the type of atom abstracted, respectively. Triplet methylene is discriminating in hydrogen abstraction from 1-C 3 H 7 Cl, the overall rates for atoms attached to C1, C2, C3 being in the ratios 2.63:1:0.

scholarly journals XII. An easy method to distill fresh water from salt water at sea; by Capt. Newland

1772 ◽  
Vol 62 ◽  
pp. 90-92 ◽  
Keyword(s):  
Fresh Water ◽  
Salt Water ◽  
Easy Method

The materials necessary for this process are the following; a copper or iron pot of 15 or 20 gallons, an empty cask, some sheet lead, a small jar, a few wood-ashes or soap, and billet-wood for fewel.

The In Vitro Sensitivities of 70 Strains of Shigella

PEDIATRICS ◽  
1964 ◽  
Vol 34 (5) ◽  
pp. 705-707
Author(s):  
WILLIAM D. DONALD
Keyword(s):  
Clinical Trials ◽  
Gastrointestinal Tract ◽  
Tetracycline Resistance ◽  
The Other ◽  
Drug Of Choice ◽  
High Degree ◽  
As Toxicity ◽  
Selection Of

In vitro sensitivities of 70 shigella strains isolated over a recent 18-month period are reported. The high degree of sulfadiazine resistance casts some doubt on the selection of this agent as the drug of choice in the treatment of shigellosis, at least in this community. Some of the other agents, although inhibiting the growth of the organisms in vitro, have disadvantages such as toxicity or failure of absorption from the gastrointestinal tract. Tetracycline resistance was found in only 7% of the organisms tested, but from this and other reports we may anticipate the occurrence of more organisms resistant to this agent. The results of the sensitivities to ampicillin are encouraging and further studies including clinical trials of this agent are in order.

Photoreceptor coupling in turtle retina

1998 ◽  
Vol 15 (4) ◽  
pp. 755-764 ◽  
Author(s):  
M.L. FIRSOV ◽  
D.G. GREEN
Keyword(s):  
Receptive Field ◽  
Gap Junctions ◽  
Direct Evidence ◽  
Physiological Responses ◽  
The Other ◽  
Morphological Data ◽  
Chelydra Serpentina ◽  
Intracellular Injection ◽  
Coupled Cells ◽  
High Degree

Photoreceptors in the isolated turtle retina of two species of turtle, Chelydra serpentina and Pseudemus scripta elegans, were penetrated with double-barrel electrodes. Physiological responses were recorded through one barrel and Neurobiotin tracer was injected from the other. Intracellular injection of Neurobiotin revealed patterns of tracer-coupled photoreceptors. Both the patterns of tracer coupling and the electrophysiology suggest a high degree of specificity of connections. Rods seem to be coupled only to rods and green and red cones seem to be coupled to cones of the same spectral type. Receptive-field profiles, measured with a thin, sharply focused slit of light, often had well-defined peaks and troughs in sensitivity. We have taken advantage of this observation and used the position of a peak in sensitivity to locate the position on the retina of a coupled cell. In one rod, it was possible to correlate physiological and morphological data and to show that the peaks in the physiological receptive field occurred at positions on the retina where there were dye-coupled cells. This provides direct evidence that gap junctions produce the physiological coupling between rods.

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