| 1. |
- Dircksen, Heinrich, 1954-, et al.
(författare)
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The ultrastructure of nerve endings containing pigment-dispersing hormone (PDH) in crustacean sinus glands: Identification by an antiserum against a synthetic PDH
- 1987
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Ingår i: Cell and Tissue Research. - : Springer. - 0302-766X .- 1432-0878. ; 250:2, s. 377-387
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Tidskriftsartikel (refereegranskat)abstract
- A high-liter antiserum has been obtained from two rabbits immunized with a glutaraldehyde conjugate of synthetic pigment-dispersing hormone (PDH) from Uca pugilator and bovine thyroglobulin. The antiserum blocked melanophore-dispersing activity of the peptide in vivo. In sinus glands (SG) of Carcinus maenas, Cancer pagurus, Uca pugilator and Orconectes limosus, electron-microscopic immunocytochemistry revealed sparsely distributed axon endings containing a distinct PDH-immunoreactive type of neurosecretory granules (diameter 90–130 nm). Exocytotic figures indicating release of the content of these granules into hemolymph lacunae were occasionally observed. Preservation of fine structure and antigenicity of the PDH granules were markedly dependent on the fixation procedure used. A preliminary experiment with C. maenas showed that preterminal axon dilatations near the basal lamina seemed to accumulate PDH-granules when animals were kept in complete darkness for three days. Immunodot blotting of fractions after high pressure liquid chromatography (HPLC) of extracts from SGs of C. maenas and O. limosus revealed a strongly immunoreactive substance at a retention time very similar to those of synthetic PDHs of Uca pugilator and Pandalus borealis. It is also coincident with a zone of biological activity. Thus, the antigen demonstrated by immunocytochemistry is identical or very similar to one of the known PDHs.
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| 2. |
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| 3. |
- Rao, K. Hanumantha, et al.
(författare)
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Selective flocculation for the recovery of iron in Kudremukh tailings
- 1985
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Ingår i: Mining engineering. - 0026-5187. ; 37:11, s. 1312-1315
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Tidskriftsartikel (refereegranskat)abstract
- A concentrate containing 63% iron can be obtained from tailings containing 34% iron with around 60% recovery. Caustic degraded tapioca starch is an effective agent for selective flocculation. While potato starch after caustic degradation can also be used, neither the parent starch nor the amylopectin compound is as effective.
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| 4. |
- Mangerich, Sigrid, et al.
(författare)
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Immunocytochemical localization of pigment-dispersing hormone (PDH) and its coexistence with FMRFamide-immunoreactive material in the eyestalks of the decapod crustaceans Carcinus maenas and Orconectes limosus
- 1987
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Ingår i: Cell and Tissue Research. - Heidelberg New York : Springer. - 0302-766X .- 1432-0878. ; 250, s. 365-375
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Tidskriftsartikel (refereegranskat)abstract
- By use of a new antiserum, raised against synthetic pigment-dispersing hormone (PDH) from Uca pugilator, immunoreactive structures were studied at the light-microscopic level in the eyestalk ganglia of Carcinus maenas and Orconectes limosus. PDH-reactivity was mainly found in two types of neurons that were located between the medulla interna (MI) and the medulla terminalis (MT) in both species. Several additional perikarya were located in the distal part of the MI in O. limosus. In C. maenas, two to three PDH-positive perikarya were found in the region of the X-organ (XO) in the MT. Processes from single and clustered cells could be traced into all medullae of the eyestalk. Axons from the immunoreactive perikarya running between MI and MT form a larger tract that traverses the MT. Fibers from this tract give rise to extensive arborizations and plexuses throughout the proximal MT. A plexus containing very fine fibers is located at the surface of the MT in a position distal to the XO-area of C. maenas only. The proximal plexus also receives PDH-positive fibers through the optic nerve. PDH-perikarya in the cerebral ganglion may also project into the more distal regions of the eyestalk. Distal projections of the perikarya between the MI and MT consist of several branches. Most of these are directed toward the MI and ME (medulla externa) wherein they form highly organized, layered plexuses. One branch was traced into the principal neurohemal organ, the sinus gland (SG). In the SG, the tract gives off arborizations and neurosecretory terminals. It then proceeds in a proximal direction out of the SG, adjacent to the MT. Its further course could not be elucidated. The lamina ganglionaris (LG) receives PDH-fibers from the ME and fine processes from small perikarya located in close association with the LG in the distal part of the first optic chiasma. The architecture of PDH-positive elements was similar in both C. maenas and O. limosus. The distribution of these structures suggests that PDH is not only a neurohormone but may, in addition, have a role as a neurotransmitter or modulator. Immunostaining of successive sections with an FMRF-amide antiserum revealed co-localization of FMRFamideand PDH-immunoreactivities in most, but not all PDH-containing perikarya and fibers. The axonal branch leading to the SG and the SG proper were devoid of FMRFamide immunoreactivity.
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| 5. |
- Rao, K. Hanumantha, et al.
(författare)
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Flotation of phosphatic material containing carbonatic gangue using sodium oleate as collector and sodium silicate as modifier
- 1989
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Ingår i: International Journal of Mineral Processing. - : Elsevier BV. - 0301-7516 .- 1879-3525. ; 26:1, s. 123-140
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Tidskriftsartikel (refereegranskat)abstract
- The effect of sodium silicate as a depressant for calcite is examined in the flotation of phosphatic material containing calcite and siliceous gangue using sodium oleate as collector. Maximum flotation of apatite occurs at pH 8, whereas the pH at which calcite floats best varies with particle size. At pH 8 and 9, sodium silicate depresses calcite to some extent beyond 1500 g/t (2·10−3 M), and the depression is more pronounced at higher pH but the recovery of apatite is correspondingly low at these pH values. Selective action of silicate on calcite surfaces can be seen from the analysis of pulp liquid. However, for the pH range 7–11 and at any sodium silicate concentration, no significant selectivity between apatite and calcite is achieved.The influence of oleate concentration, pH and the concentration of sodium silicate on the flotation behaviour are discussed in detail.
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| 7. |
- Rao, K. Hanumantha, et al.
(författare)
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Mechanism of oleate interaction on salt-type minerals part I. Adsorption and electrokinetic studies of calcite in the presence of sodium oleate and sodium metasilicate
- 1988
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Ingår i: Colloids and Surfaces. - 0166-6622 .- 1873-4340. ; 34:3, s. 227-239
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption mechanism of oleate on calcite is investigated through adsorption and electrokinetic studies. The adsorption isotherms at pH 9, 10 and 11 show a plateau value at an oleate adsorption density of 5.7 μmol m-2, which virtually corresponds to the monolayer coverage of the bidimensional condensed state of oleate with a reported molecular coverage area of 33 angstrom2 (liquid-crystal state). A steep increase increase in the slope of the isotherms characterizing calcium oleate precipitation appears after monolayer coverage and the solubility product of calcium oleate is found to be in the range pK 13.65-13.87 from the solution conditions. The zeta potentials correspond to the adsorption of oleate until monolayer coverage, and physical adsorption of precipitated calcium oleate on top of the chemisorbed oleate layer is also confirmed.
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