ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Polymer and Materials Science  (38)
  • BIOSCIENCES  (7)
  • Drosophila  (5)
  • 1
    Electronic Resource
    Electronic Resource
    A high-resolution morphogenetic map of the second-leg basitarsus inDrosophila melanogaster (1979)
    Springer
    Development genes and evolution 187 (1979), S. 129-150 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Pattern formation ; Leg ; Bristle ; Cell lineage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The lineages of cells on the second-leg basitarsus ofDrosophila melanogaster were analyzed by examining gynandromorphs andMinute mosaics. Bracts lie proximal to bristles on the adult basitarsus, yet bract precursor cells were found to originate lateral to bristle precursor cells. In 6 of the 8 longitudinal rows of bristles on this segment, the bract cells arise ventral to the bristle cells; in the others they arise dorsally. The lateral cell origins are interpreted as reflecting a pattern of lateral cell movements associated with evagination of the leg disc. An unusual discrepancy was observed in the relative frequencies of male vs. female bracts and bristles in gynandromorphs. The discrepancy suggests that there is a cell-autonomous sexual difference in either the time at which cells begin moving during evagination or the speed with which they move. On the basis of the results, it is reasoned that the bristle pattern of the basitarsus does not originate in its final form. Prior to evagination, the bristle cells of each row are apparently closer together than in the final pattern, and the rows are farther apart. Evidence is presented which suggests that the bristle cells of each row may originally be arranged in a jagged line which is later straightened by cell movements. The two locations where the anterior/posterior compartment boundary of the second leg passes through the basitarsus were found to vary relative to the bristle pattern. If this boundary is assumed to be a fixed line of positional values, then the extent of the observed variability — which is estimated to be ± 1 or 2 cell diameters — provides a measure of the precision of patterning around the circumference.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848267
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Sensitive periods for abnormal patterning on a leg segment inDrosophila melanogaster (1990)
    Springer
    Development genes and evolution 199 (1990), S. 31-47 
    Details
    ISSN: 1432-041X
    Keywords: Bristle ; Pattern formation ; Drosophila ; Gamma rays ; Mitomycin C ; Heat shock
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of a leg segment of the fruitflyDrosophila melanogaster was analyzed in order to determine whether the orderliness of the segment's bristle pattern originates via waves of cellular interactions, such as those that organize the retina. Fly development was perturbed at specific times by either teratogenic agents (gamma rays, heat shock, or the drug mitomycin C) or temperature-sensitive mutations (l(1)63, l(1) Notchts1, orl(1) shibire ts1 ), and the resulting abnormalities (e.g., missing or extra structures) were mapped within the pattern area. If bristles develop in a linear sequence across the pattern, then they should show sensitivity to perturbations in the same order, and wavefronts of cuticular defects should result. Contrary to this prediction, the maps reveal no evidence for any directional waves of sensitivity. Nevertheless, other clues were uncovered as to the nature and timing of patterning events. Chemosensory bristles show earlier sensitivities than mechanosensory bristles, and longer bristles precede shorter ones. The types and sequence of cuticular abnormalities imply the following stages of bristle pattern development: (1) scattered inception of bristle mother cells, each surrounded by an inhibitory field, (2) alignment of the mother cells into rows, (3) differential mitoses, (4) assignment of cuticular fates to the mitotic progeny, (5) polytenization of the bristle cells, (6) fine-tuning adjustments in bristle spacing, and (7) signalling from bristle cells to adjacent epidermal cells, inducing them to form “bracts”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01681531
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Arrangement of bristles as a function of bristle number on a leg segment inDrosophila melanogaster (1990)
    Springer
    Development genes and evolution 199 (1990), S. 48-62 
    Details
    ISSN: 1432-041X
    Keywords: Bristle ; Sensilla ; Pattern formation ; Drosophila ; achaete-scute complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The arrangement of bristles on a leg segment of the fruitflyDrosophila melanogaster was studied in various mutants that have abnormal numbers of bristles on this segment. Eighteen mutations at six different genetic loci were analyzed, plus five double or triple mutant combinations. Recessive mutations at theachaete-scute locus were found to affect distinct groups of bristles:achaete mutations remove mechanosensory bristles, whereasscute mutations remove mainly chemosensory bristles. Mechanosensory bristles remain uniformly spaced along the longitudinal axis unless their number decreases below a certain threshold, suggesting that spacing is controlled by cell interactions that cannot function when bristle cells are too far apart. Above a certain threshold, bristle spacing and alignment both become irregular, perhaps due to excessive force from these same interactions. Chemosensory bristles occupy definite positions that are virtually unaffected by removal of individual bristles from the array. Extra chemosensory bristles develop only near the six normal sites. At two of the six sites the multiple bristles tend to exhibit uniform longitudinal spacing — a property confined to mechanosensory bristles in wild-type flies. To explain the various mutant phenotypes the following scheme is proposed, with different mutations directly or indirectly affecting each step: (1) spots and stripes are demarcated within the pattern area, (2) one bristle cell normally arises within each spot, multiple bristle cells within each stripe, (3) incipient bristle cells inhibit neighboring cells from becoming bristle cells, and (4) the bristle cells within each stripe become aligned to form rows and then repel one another to generate uniform spacing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01681532
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Pattern as a function of cell number and cell size on the second-leg basitarsus ofDrosophila (1979)
    Springer
    Development genes and evolution 187 (1979), S. 105-127 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Pattern formation ; Leg ; Bristle ; Evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The bristle pattern of the second-leg basitarsus inDrosophila melanogaster was studied as a function of the number and size of the cells on this segment in well-fed and starved wild-type flies, in triploid flies, and in two mutants (dachs andfour-jointed) that have abnormally short basitarsi. The second-leg basitarsi of well-fed, wild-type flies from 22 otherDrosophila species were studied in a similar manner. There are typically 8 longitudinal rows of evenly-spaced bristles on the second-leg basitarsus, and in each row the number of bristles was consistently found to vary in proportion to the estimated number of cells along the segment, and the interval between bristles was found to vary in proportion to the average cell diameter on the segment. These correlations are interpreted to mean that the spacing of the bristles within each row is controlled developmentally, whereas the number of bristles is not. The interval between bristles is evidently measured either as a fixed number of cells or as a distance which indirectly depends upon cell diameter.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848266
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Extra tarsal joints and abnormal cuticular polarities in various mutants ofDrosophila melanogaster (1986)
    Springer
    Development genes and evolution 195 (1986), S. 145-157 
    Details
    ISSN: 1432-041X
    Keywords: Drosophila ; Cell polarity ; Limb development ; Pattern formation ; Bristle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The legs of flies from 16 different mutant strains ofDrosophila melanogaster were examined for abnormal cuticular polarities and extra joints. The strains were chosen for study because they manifest abnormal cuticular polarities in some parts of the body (10 strains) or because they have missing or defective tarsal joints (6 strains). All but three of the stocks were found to exhibit misorientations of either the bristles, hairs, or “bract-socket vectors” on the legs. The latter term denotes an imaginary vector pointing from a hairlike structure called a “bract” to the bristle socket with which it is associated. On the legs of wild-type flies nearly all such vectors point distally, as do the bristles and hairs. In the mutant flies, the most common vector misorientation is a 180° reversal. When the bract-socket vectors of adjacent bristle sites in the same bristle row point toward one another, the distance between the sites is frequently abnormally large, whereas when the vectors point in opposite directions, the interval is frequently abnormally small. This correlation is interpreted to mean that bristle cells actively repel one another via cytoplasmic extensions that are longer in the direction of the bract-socket vector than in the opposite direction. Repulsive forces of this kind may be responsible for “fine-tuning” the regularity of bristle spacing in wild-type flies. Extra tarsal joints were found in eight of the 16 strains. A ninth strain completely lacking tarsal joints appears in some cases to have an extra tibia-basitarsus joint in its tibia. Whereas the tarsi of wild-type flies contain four joints, the tarsi ofspiny legs mutant flies contain as many as eight joints. In this extreme extra-joint phenotype, four of the joints correspond to the normal wild-type joints, and there is an extra joint in every tarsal segment except the distal-most (fifth) segment. Nearly all such ectopic extra joints have inverted polarity. In other strains the extra tarsal joints are located mainly at the wild-type joint sites, and joints of this sort have wild-type polarity. The alternation of normal and inverted (extra) joints inspiny legs resembles the alternation of normal and inverted (extra) body segment boundaries in the embryonic-lethal mutantpatch, suggesting that tarsal and body segmentation may share a common patterning mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02439432
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    A DSC study of the polymerization of 2-Vinylpyridine in dimethylformamide (1985)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 131 (1985), S. 117-123 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Polymerisation von 2-Vinylpyridine (2VP) in Dimethylformamid (DMF) mit Azobisisobutyronitril (AIBN) als Initiator wurde mit einem Differential Scanning Kalorimeter studiert. Wenn für die Untersuchungen hinreichende Mengen AIBN verwendet werden und die Werte hinsichtlich der Zersetzungsenthalpie korrigiert werden, können die folgenden Werte erhalten werden:Polymerisationsenthalpie ΔHp,o = -68 ± 4 kJ/mol; Arrhenius-Parameter für die gesamte Reaktion Ea = 90.0 ± 4 kJ/mol and in A = 24 ± 1.0 (A = 2.6 × 1010 dm3/2/mol1/2. s).
    Notes: The polymerization of 2-vinylpyridine (2VP) in dimethylformamide (DMF) with azobisisobutyronitrile (AIBN) as initiator was studied with a differential scanning calorimeter. By taking an appropriate amount of AIBN and after correction for its decomposition, the following values could be obtained:Heat of polymerization ΔHp,o = -68 ± 4 kJ/mol; overall Arrhenius activation parameters Ea = 90.0 ± 4 kJ/mol and ln A = 24 ± 1.0 (A = 2.6 × 1010 dm3/2/mol1/2. s).
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1985.051310109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Alternative Kraftstoffe: Chancen und AufgabenVortrag auf dem Jahrestreffen der Verfahrens-Ingenieure, 1. bis 3. Okt. 1980 in Straßburg. (1981)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 53 (1981), S. 82-89 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Description / Table of Contents: Alternative fuels: Possibilities and problems. The world's supply of fossil fuels is limited. The motor vehicle industry is striving to develop substitutes for crude oil and reduce its rate of consumption in the following ways. 1. Reduction of fuel consumption through improvements in the vehicle (weight, aerodynamics), the engine and the transmission as well as engine-transmission management. Future development possibilities along these lines are presented. 2. Utilisation of alternative fuels. The various possible alternative fuels are compared with one another and evaluated. Gaseous fuels (LPG) and liquid fuels (methanol and ethanol) appear promising, since the technical problems which still exist can be solved in the medium-term. Designs are presented both for vehicles operating on pure alcohol and for vehicles using an alcohol-petrol mixture. Preliminary experimental results are reported.
    Notes: Die Verfügbarkeit von fossilen Energie-Trägern ist begrenzt. Die Automobil-Industrie bemüht sich, durch folgende Maßnahmen zur Einsparung und Substitution von Rohöl beizutragen: 1. Verringerung des Kraftstoffverbrauchs durch Optimierung des Fahrzeuges (Gewicht, Aerodynamik), Motor und Getriebe sowie Motor/Getriebe-Management. Es werden hierzu zukünftige Entwicklungsmöglichkeiten vorgestellt. 2. Einsatz von alternativen Kraftstoffen. Es werden die verschiedenen Möglichkeiten des Einsatzes alternativer Kraftstoffe miteinander verglichen und bewertet. Recht aussichtsreich erscheint der Einsatz von gasförmigen (LPG) und flüssigen Kraftstoffen (Methanol und Ethanol), bei denen sich die noch offenen technischen Fragen mittelfristig lösen lassen. Es werden Fahrzeugkonzepte für den Reinalkohol- und Alkoholmischkraftstoff-Betrieb vorgestellt und erste Versuchsergebnisse mitgeteilt.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330530203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Scanning Near-field Magneto-optic Microscopy: Quantitative Measurements of Local Faraday Effects (1997)
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 25 (1997), S. 483-487 
    Details
    ISSN: 0142-2421
    Keywords: scanning near-field optical microscopy (SNOM, NSOM) ; magneto-optic Faraday effect ; garnet films ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: The implementation of a phase-modulating polarization detector into a scanning near-field optical microscope allows the imaging of local magneto-optic effects with spatial resolution. By taking several pictures at the same location with different detector settings, a quantitative evaluation of magneto-optic effects, such as Faraday rotation, becomes possible. Images were taken from thin garnet films using this method.©1997 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 9
    Electronic Resource
    Electronic Resource
    Blast Waves in Free Air (1983)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 8 (1983), S. 1-7 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Simple equations are given which can be used for calculating the approximate values of peak overpressure and positive phase impulse of blast waves generated by the detonation of military high explosive charges in the free atmosphere. To the practitioner, these equations may be useful in the quick and simple design of protective systems, or in calculating the amount of explosive required to achieve a certain desired effect. Moreover, an outline is given of the derivation of simple equations for the damaging effect of blast waves as a function of distance and charge weight. A useful formula, which had been given by Westine, encompasses the following three main causes of a damaging effect: -peak overpressure, if the blast duration is long as compared to the natural vibration period of the target structure;-pressure impulse, if the blast duration is short as compared to the natural vibration period of the target structure;-product of peak overpressure multiplied by impulse in the intermediate range, i.e., if the duration of the pressure pulse is comparable to the natural vibration period of the target structure.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19830080102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Experiments of Initiation of Covered, but Unconfined High Explosive Charges by means of shaped charge jets (1987)
    Weinheim : Wiley-Blackwell
    Propellants, Explosives, Pyrotechnics 12 (1987), S. 35-40 
    Details
    ISSN: 0721-3115
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Experiments on the initiation of high explosive charges in contact with a barrier or separated from it by a 15 mm air gap or a 2 mm acrylic glass layer have been performed utilising a simultaneous framing and streak camera. With increasing barrier thickness the shaped charge jet is increasingly consumed.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prep.19870120202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...