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472. A Mediterranean population of Pyrrhocoris apterus (Heteroptera: Pyrrhocoridae) exhibits wing morph-related differences in adipokinetic response
- Creator:
- Kodrík, Dalibor and Socha, Radomír
- Format:
- print, text, and regular print
- Type:
- article, bibliography, model:article, and TEXT
- Subject:
- zoologie, entomologie, hmyz, ploštice, Pyrrhocoridae, Pyrrhocoris apterus, křídla, dimorfismus křídel, neurohormony, adipokinetické hormony, funkce, 595.2/.7, and 591.1
- Language:
- English
- Description:
- Short-winged (brachypterous) and long-winged (macropterous) adult females of Pyrrhocoris apterus (L.) originating from a Mediterranean population (Israel) were analyzed for their adipokinetic responses. The adipokinetic response, expressed as an increase of haemolymph lipids after injection of adipokinetic hormone from Locusta migratoria (Lom-AKH-I), was assessed in relation to age and dose of the hormone. We demonstrate in this study that the adipokinetic responses induced by bug's corpora cardiaca extract and Lom-AKH-I were dose-dependent for both brachypterous and macropterous females. Significant differences between the morphs were recorded for doses >= 0.25 corpora cardiaca equivalent (P < 0.01) and doses >= 0.25 pmol Lom-AKH-I (P < 0.05). The haemolymph lipid elevations induced in both morphs by 2 pmols Lom-AKH-I are comparable with that induced by crude extract of one pair of the bug's own corpora cardiaca. The age-dependent test showed much higher adipokinetic responses (P < 0.01) in macropterous females (>= 5 days old) than in the brachypterous females of the same age, when treated with 2 pmols Lom-AKH-I. Starting from day 7, the concentration of haemolymph lipids was also considerably higher (2.5-5 times) in macropterous females than in the brachypterous ones. The obtained data indicate that difference in mobilization of lipids between brachypterous and macropterous females is a geographically independent feature and represents a true wing morph characteristic of P. apterus., Dalibor Kodrík, Radomír Socha, and Lit
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
473. A method of resolution improvement by the measurement of cell membrane capacitance
- Creator:
- Rech, F., Rohlíček, V., and Schmid, A.
- Type:
- article, model:article, and TEXT
- Subject:
- patch-clamp technique, membrane capacitance, membrane, conductance, series resistance, exocytosis, and dual-frequency method
- Language:
- English
- Description:
- When measuring cell membrane electrical capacitance in whole cell configuration using alternating currents, the resolution decreases with increasing membrane conductance and pipette resistance. Improved resolution was attained by the dual-frequency method which was modified as to control the voltage amplitude of one of the measuring frequencies. A model circuit was developed for the verification of the method. This circuit allows measurement of calibrated capacitance changes even in the range of 5 to 20 fF. Moreover, the method was applied to capacitance measurements on pancreatic exocrine acinar cells. The results of measurements on the model as well as on pancreatic acinar cells are presented. The principle can also be applied to other hardware and software methods for measuring electrical cell membrane parameters.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
474. A method with enhanced sensitivity for temperature measurement in living tissues
- Creator:
- Rech, F., Dittert, I., and Rohlíček, V.
- Type:
- article, model:article, and TEXT
- Subject:
- microsensor, temperature measurement, and electrical admittance measurement
- Language:
- English
- Description:
- A system for the evaluation of temperature changes in living tissue at a dimensional level of a single cell is described. A glass micropipette the tip of which is filled with semiconducting glass (Rech et al. 1992), is used as a microsensor. The changes of conductivity of the sensor due to variations of temperature are evaluated by electronic circuitry based on the measurement of an AC current of sinusoidal waveform flowing through the sensor. Temperature changes in the range of 0.01 K can be detected in this way.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
475. A model of rock mass fracturing ahead of the longwall face as a consequence of intensity of exploitation
- Creator:
- Drzewiecki, Jan and Makówka, Janusz
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, geodynamika, geodynamics, 7, and 551
- Language:
- English
- Description:
- In Czech and Polish underground hard coal mines of the Upper Silesian Coal Basin high-energy seismic phenomena are periodically recorded, the sources of which are located ahead of the longwall. Generally, these types of tremors are rooted in very strong, thick layers of sandstone, which are subject to the deformation border. The consequences are discontinuities and cracks with a range depending on the mechanical properties of destroyed rocks: the mechanical parameters of layers. Forecasting methods, developed in the Central Mining Institute, for stress concentration, seismic energy, fault zone and range, together with methods of rock fracturing using liquid or explosives, ,allow precise identification of suitable locations for controlled fracturing of rock mass with a pre-established direction. The size and range of discontinuities have an impact on mining parameters, dependent on basic exploitation intensity and expressed by the average daily progress of the longwall face. The rockmass is locally weakened because of exploitation or technical measures of discontinuities in the roof-rock on the longwall face. To prevent rockburst, measures are needed to reduce the amount of energy accumulating in the rockmass in the area of the longwall face. Knowledge of where stress is concentrated is extremely important for the development and implementation of effective preventative methods. For many years several research centres have been working on defining the range of these areas. In this paper, basic information is presented on methods developed by Central Mining Institute and used in Polish hard coal mines for forecasting energy concentration and assessing how it can be reduced., Jan Drzewiecki and Janusz Makówka., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
476. A model of stochastic activity of neurone in some types of gaussian input processes
- Creator:
- Novák, V. and Schmidt, J.
- Type:
- article, model:article, and TEXT
- Subject:
- model of neuronal stochastic activity, e-curves, interspike interval density distribution, and stochastic transformations
- Language:
- English
- Description:
- A new approach to computer modelling of neuronal stochastic activity is described. The output dynamic activity which depends on the types and the number of input synapses, weights of the synaptic efficacy, the absolute refractory phase duration and threshold level is evaluated on this model in some types of Gaussian input processes. The behaviour of this model for one excitatory and one inhibitory synapse is described in dependence on the changes of excitation weight. The neuronal behaviour presented depends on the number of interspike intervals and the excitation weight and interspike interval density distribution. A novel concept of the e-curve is being introduced, which shows the dependence of the number of output interspike intervals on the weight of excitation on a stable inhibition level, the absolute refractory phase value and the threshold level. The properties of e-curves are discussed. Furthermore, examples of transformations of input stochastic processes are mentioned from the aspect of density distribution changes of interspike intervals.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
477. A modified hydrodynamic model for routing unsteady flow in a river having piedmont zone
- Creator:
- Patowary, Sudarshan and Sarma, Arup Kumar
- Type:
- article, model:article, and TEXT
- Subject:
- groundwater flow, numerical modeling, piedmont zone, Green-Ampt. Equation, and surface water equation
- Language:
- Slovak
- Description:
- Existence of piedmont zone in a river bed is a critical parameter from among numerous variations of topographical, geological and geographical conditions that can significantly influence the river flow scenario. Downstream flow situation assessed by routing of upstream hydrograph may yield higher flow depth if existence of such high infiltration zone is ignored and therefore it is a matter of concern for water resources planning and flood management. This work proposes a novel modified hydrodynamic model that has the potential to accurately determine the flow scenario in presence of piedmont zone. The model has been developed using unsteady free surface flow equations, coupled with Green-Ampt infiltration equation as governing equation. For solution of the governing equations Beam and Warming implicit finite difference scheme has been used. The proposed model was first validated from the field data of Trout Creek River showing excellent agreement. The validated model was then applied to a hypothetical river reach commensurate with the size of major tributaries of Brahmaputra Basin of India. Results indicated a 10% and 14% difference in the maximum value of discharge and depth hydrograph in presence and absence of piedmont zone respectively. Overall this model was successfully used to accurately predict the effect of piedmont zone on the unsteady flow in a river.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
478. A modified method for clearing, staining and mounting plant-inhabiting mites
- Creator:
- Faraji, Farid and Bakker, Frank
- Type:
- article, model:article, and TEXT
- Subject:
- Acari, iodine, staining, and microscope slides
- Language:
- English
- Description:
- A modified method for clearing, staining and mounting plant-inhabiting mites is proposed. With this method, all mites can be cleared with a single agent and mounted in a single medium. The stain added to the mounting medium enhances the clarity of the fine structures of soft-bodied mites under phase contrast and more significantly under bright field microscopy.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
479. A molecular phylogeny of Polyommatus s. str. and Plebicula based on mitochondrial COI and nuclear ITS2 sequences (Lepidoptera: Lycaenidae)
- Creator:
- Wiemers, Martin, Stradomsky, Boris V., and Vodolazhsky, Dmtrij I.
- Type:
- article, model:article, and TEXT
- Subject:
- Lycaenidae, Polyommatus, molecular phylogeny, mitochondrial COI, nuclear ITS2, Plebicula, and Polyommatus celina
- Language:
- English
- Description:
- The phylogenetic relationships of the subgenera Polyommatus and Plebicula, within the Palaearctic butterfly genus Polyommatus, were inferred from a combined analysis of the nuclear marker ITS2 and the barcoding section of the mitochondrial gene COI. Eight major clades were recovered within Polyommatus s. l., which correspond closely to subgenera based on traditional systematics and are of late Pliocene to early Pleistocene origin. Extraordinary chromosomal evolution occurred independently in three of these clades. The disputed position of several species formerly placed in the subgenus Plebicula is clarified. A group of Central Asian species (Bryna) was recovered as a monophyletic clade within Polyommatus s. str. The Kurdistanian endemic P. buzulmavi appears as a sister species to P. icarus. P. celina replaces P. icarus in NW Africa and the Canary Islands, and split from the last common ancestor with P. icarus back in the early Pleistocene.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
480. A monitoring of allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes after ten minutes of running activity
- Creator:
- Roman Kanďár, Štramová, X., Drábková, P., and Jarmila Křenková
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, kyselina močová, oxidační stres, antioxidanty, uric acid, oxidative stress, antioxidants, allantoin, short-term intense exercise, 14, and 612
- Language:
- English
- Description:
- Uric acid is the final product of human purine metabolism. It was pointed out that this compound acts as an antioxidant and is able to react with reactive oxygen species forming allantoin. Therefore, the measurement of allantoin levels may be used for the determination of oxidative stress in humans. The aim of the study was to clarify the antioxidant effect of uric acid during intense exercise. Whole blood samples were obtained from a group of healthy subjects. Allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes were measured using a HPLC with UV/Vis detection. Statistical significant differences in allantoin and uric acid levels during short-term intense exercise were found. Immediately after intense exercise, the plasma allantoin levels increased on the average of 200 % in comparison to baseline. Plasma uric acid levels increased slowly, at an average of 20 %. On the other hand, there were no significant changes in plasma malondialdehyde. The results suggest that uric acid, important antioxidant, is probably oxidized by reactive oxygen species to allantoin. Therefore allantoin may be suitable candidate for a marker of acute oxidative stress., R. Kanďár, X. Štramová, P. Drábková, J. Křenková., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public