scholarly journals Analyses of the mouthpart kinematics in Periplaneta americana (Blattodea, Blattidae) using synchrotron-based X-ray cineradiography

2014 ◽  
Vol 217 (17) ◽  
pp. 3095-3107 ◽  
Author(s):  
C. Schmitt ◽  
A. Rack ◽  
O. Betz
Keyword(s):  
1963 ◽  
Vol 40 (4) ◽  
pp. 763-773
Author(s):  
K. G. DAVEY ◽  
J. E. TREHERNE

1. The structure and mode of action of the proventriculus are described. 2. X-ray photographs have shown that as the crop empties the decrease in volume of the fluid is partially compensated for by the swallowing of air. 3. The effects of various factors upon the rate of crop-emptying have been studied using solutions of different osmotic pressures. Changes in viscosity, effected by the addition of methyl cellulose, produce only a minor reduction in crop-emptying. The frequency of opening of the proventricular valve is not proportional to the rate of crop-emptying over the whole range of concentrations used, and it is assumed that changes in other parameters must affect the process.


2002 ◽  
Vol 67 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Brunhilde Voigt ◽  
Andrea Porzel ◽  
Günter Adam ◽  
Dieter Golsch ◽  
Waldemar Adam ◽  
...  

Investigations of the metabolic conversion of the phytohormone 24-epicastasterone (1) in the cockroach Periplaneta americana (L.) required the synthesis of 2,24-diepicastasterone (4), 3,24-diepicastasterone (7b) and 2-dehydro-3,24-diepicastasterone (9) as reference standards. 2,24-Diepicastasterone (4) was synthesized from 2α,3α-epoxy derivative 2 as well as from the 2β,3β-epoxy-22,23-diol 3 by acid-catalyzed water addition to the epoxy function leading to the desired 2β,3α-trans functionality. 3,24-Diepicastasterone (7b) was prepared by NaBH4-reduction of the 3-oxo derivative 6. Upon deprotection conditions from the ketol acetonides 6 and 8 in both cases 2-dehydro-3,24-diepicastasterone (9) was obtained. The structure of 2,24-diepicastasterone (4) was confirmed by X-ray analysis.


Author(s):  
Vandana K. Hivrale ◽  
Nanasaheb P. Chougule ◽  
Pavan J. Chhabda ◽  
Ashok P. Giri ◽  
Manvendra S. Kachole

1983 ◽  
Vol 244 (2) ◽  
pp. R176-R186 ◽  
Author(s):  
B. L. Gupta ◽  
T. A. Hall

The compound, racemose, innervated salivary glands of the cockroach Periplaneta americana closely resemble in structure and function the mammalian salivary glands (C.R. House, Biol. Rev. 55: 417-473, 1980). The quantitative distribution of Na, K, Cl, Ca, Mg, P, and S was investigated in the P-cells secreting isotonic NaCl and in duct lumens by using electron probe X-ray microanalysis of frozen-hydrated and frozen-dried cryosections. In the unstimulated glands in vitro the cells had (mmol/l cell-H2O) Na, 10; K, 110; Cl, 39 while the primary saliva had Na, 153; K, 4; Cl, 151. With 1 mumol dopamine in the bathing Ringer solution the P-cells had Na, 25; K, 177; Cl, 58 and the primary saliva, Na, 153; K, 26; Cl, 172. During passage through the ducts, the primary saliva was modified by an absorption of NaCl: more in unstimulated than in stimulated glands. It is proposed that the cells have a Na-K-ATPase both in the apical and basal cell membrane, as in vertebrate choroid plexus, and dopamine might increase the K and Na conductance of the basal cell membrane.


1994 ◽  
Vol 144 ◽  
pp. 275-277
Author(s):  
M. Karlický ◽  
J. C. Hénoux

AbstractUsing a new ID hybrid model of the electron bombardment in flare loops, we study not only the evolution of densities, plasma velocities and temperatures in the loop, but also the temporal and spatial evolution of hard X-ray emission. In the present paper a continuous bombardment by electrons isotropically accelerated at the top of flare loop with a power-law injection distribution function is considered. The computations include the effects of the return-current that reduces significantly the depth of the chromospheric layer which is evaporated. The present modelling is made with superthermal electron parameters corresponding to the classical resistivity regime for an input energy flux of superthermal electrons of 109erg cm−2s−1. It was found that due to the electron bombardment the two chromospheric evaporation waves are generated at both feet of the loop and they propagate up to the top, where they collide and cause temporary density and hard X-ray enhancements.


1994 ◽  
Vol 144 ◽  
pp. 1-9
Author(s):  
A. H. Gabriel

The development of the physics of the solar atmosphere during the last 50 years has been greatly influenced by the increasing capability of observations made from space. Access to images and spectra of the hotter plasma in the UV, XUV and X-ray regions provided a major advance over the few coronal forbidden lines seen in the visible and enabled the cooler chromospheric and photospheric plasma to be seen in its proper perspective, as part of a total system. In this way space observations have stimulated new and important advances, not only in space but also in ground-based observations and theoretical modelling, so that today we find a well-balanced harmony between the three techniques.


1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.


1988 ◽  
Vol 102 ◽  
pp. 47-50
Author(s):  
K. Masai ◽  
S. Hayakawa ◽  
F. Nagase

AbstractEmission mechanisms of the iron Kα-lines in X-ray binaries are discussed in relation with the characteristic temperature Txof continuum radiation thereof. The 6.7 keV line is ascribed to radiative recombination followed by cascades in a corona of ∼ 100 eV formed above the accretion disk. This mechanism is attained for Tx≲ 10 keV as observed for low mass X-ray binaries. The 6.4 keV line observed for binary X-ray pulsars with Tx> 10 keV is likely due to fluorescence outside the He II ionization front.


1988 ◽  
Vol 102 ◽  
pp. 357-360
Author(s):  
J.C. Gauthier ◽  
J.P. Geindre ◽  
P. Monier ◽  
C. Chenais-Popovics ◽  
N. Tragin ◽  
...  

AbstractIn order to achieve a nickel-like X ray laser scheme we need a tool to determine the parameters which characterise the high-Z plasma. The aim of this work is to study gold laser plasmas and to compare experimental results to a collisional-radiative model which describes nickel-like ions. The electronic temperature and density are measured by the emission of an aluminium tracer. They are compared to the predictions of the nickel-like model for pure gold. The results show that the density and temperature can be estimated in a pure gold plasma.


1988 ◽  
Vol 102 ◽  
pp. 339-342
Author(s):  
J.M. Laming ◽  
J.D. Silver ◽  
R. Barnsley ◽  
J. Dunn ◽  
K.D. Evans ◽  
...  

AbstractNew observations of x-ray spectra from foil-excited heavy ion beams are reported. By observing the target in a direction along the beam axis, an improvement in spectral resolution, δλ/λ, by about a factor of two is achieved, due to the reduced Doppler broadening in this geometry.


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