microstructures
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sv.
- MeSH
- mikroskopie MeSH
- spektrální analýza MeSH
- Publikační typ
- periodika MeSH
- Konspekt
- Patologie. Klinická medicína
- NLK Obory
- radiologie, nukleární medicína a zobrazovací metody
The precopulatory behaviour of the larviform females of Ripidius quadriceps Abeille de Perrin, 1872 is described. The calling posture of virgin females is documented. The cephalic morphology and microstructures are visualised using scanning electron microscopy, in particular the secretory pores in the cuticle of inflatable maxillary palps. An exhaustive overview of relevant publications revealed that the location of secretory pores on the head of females is unique within the order Coleoptera. Compared to other beetles with sedentary calling females, the calling phase of the short-lived and non-feeding female of Ripidius is exceptionally short. For bioassays, various traps using virgin females of Ripidius were tested. It is likely that the sedentary behaviour of the short-lived female combined with a unique morphology and priority for investing in reproduction is compensated for by the actively flying males with remarkably flabellate antennae. The life cycle of this species, including some of the exceptions recorded at the individual level, is discussed. Perspectives for a biological and morphological survey of this rarely collected western Palaearctic species are outlined. In addition, the calling behaviour, secretory sites and location of pheromone glands in females of Coleoptera producing long range pheromones is reviewed.
- MeSH
- brouci anatomie a histologie růst a vývoj ultrastruktura MeSH
- hlava anatomie a histologie MeSH
- rozmnožování MeSH
- stadia vývoje * MeSH
- vokalizace zvířat fyziologie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Megasecoptera are insects with haustellate mouthparts and petiolate wings closely related to Palaeodictyoptera and one of the few insect groups that didn't survive the Permian-Triassic mass extinction. Recent discovery of Brodioptera sinensis in early Pennsylvanian deposits at Xiaheyan in northern China has increased our knowledge of its external morphology using conventional optical stereomicroscopy. Environmental scanning electron microscopy (ESEM) of structures, such as antennae, mouthparts, wing surfaces, external copulatory organs and cerci have shed light on their micromorphology and supposed function. A comparative study has shown an unexpected dense pattern of setae on the wing membrane of B. sinensis. In addition, unlike the results obtained by stereomicroscopy it revealed that the male and female external genitalia clearly differ in their fine structure and setation. Therefore, the present study resulted in a closer examination of the microstructure and function of previously poorly studied parts of the body of Paleozoic insects and a comparison with homologous structures occurring in other Palaeodictyopteroida, Odonatoptera and Ephemerida. This indicates, that the role and presumptive function of these integumental protuberances is likely to have been a sensory one in the coordination of mouthparts and manipulation of stylets, escape from predators, enhancement of aerodynamic properties and copulatory behaviour.
- MeSH
- anatomické struktury zvířat fyziologie ultrastruktura MeSH
- hmyz klasifikace fyziologie ultrastruktura MeSH
- skenovací elektrochemická mikroskopie MeSH
- zkameněliny * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The presented study deals with the effect of the cremation temperature on the microstructure and morphology of the human compact bone. The biological material consisted of samples from ribs of recent Central European origin belonging to individuals of known age, sex and cause of death. Each bone sample was divided into several sections. One section remained unburned and the rest were burned at 700, 800 and 1000 degrees C. A few samples were burned also at the temperature of 600 degrees C. The undecalcified unstained ground cross-sections were made from burned and unburned bones; photographed and analysed using the SigmaScan Pro 5 programme. During burning, both the macroscopic and microscopic dimensions of the bone shrink, including the measures of the individual microstructures. The percentual representation of the area of individual microstructures on the area of the cross-section decreases. The number of individual microstructures per mm2 of the compact bone cross-section increases. Most microstructural variables demonstrated statistically significant differences at the individual temperatures of cremation. The burned bones showed a large scale of the colours, especially at 700 degrees C.
- MeSH
- antropologie fyzická MeSH
- dospělí MeSH
- histocytochemie MeSH
- kremace * MeSH
- lidé MeSH
- vysoká teplota MeSH
- žebra chemie účinky záření ultrastruktura MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Three different microstructures--equiaxed, bi-modal and coarse lamellar--are prepared from Ti-6Al-4V alloy. Electric discharge machining (EDM) with a high peak current (29 A) is performed in order to impose surface roughness and modify the chemical composition of the surface. Detailed scanning electron microscopy (SEM) investigation revealed a martensitic surface layer and subsurface heat affected zone (HAZ). EDX measurements showed carbon enriched remnants of the EDM process on the material surface. Rotating bending fatigue tests are undertaken for EDM processed samples for all three microstructures and also for electropolished-benchmark-samples. The fatigue performance is found to be rather poor and not particularly dependent on microstructure. The bi-modal microstructure shows a slightly superior high cycle fatigue performance. This performance can be further improved by a suitable heat treatment to an endurance limit of 200 MPa.
8 sv.
The current study was conducted to evaluate the effect of the addition of selected hydrocolloids [agar (AG), κ-carrageenan (KC), or gelatin (PG); as a total replacement for emulsifying salts] on the viscoelastic properties and microstructure of processed cheese (PC) samples during a storage period of 60 days (at 6 ± 2 °C). In general, PC viscoelastic properties and microstructure were affected by the addition of hydrocolloids and the length of storage time. The evaluated PC reported a more elastic behavior (G' > G′′) over the viscous one. The highest values of viscoelastic moduli (G'; G′′; G*) were recorded for PC samples manufactured with KC addition, followed by those prepared with AG and PG. The control sample presented values of viscoelastic moduli similar to those of the PG sample. All PC samples tested had fat globule size values lower than 1 μm. Moreover, PC with AG and KG addition presented similar microstructures and sizes of fat globules.
- Publikační typ
- časopisecké články MeSH
The neural architecture of the corpus callosum shows pronounced inter-individual differences. These differences are thought to affect timing of interhemispheric interactions and, in turn, functional hemispheric asymmetries. The present study aimed at elucidating the neuronal mechanisms underlying this relationship. To this end, we used a combined DTI and EEG study design. In 103 right-handed and healthy adult participants, we determined the microstructural integrity of the posterior third of the corpus callosum and examined in how far this microstructural integrity was related to between-hemisphere timing differences in neurophysiological correlates of attentional processes in the dichotic listening task. The results show that microstructural integrity of the posterior callosal third correlated with attentional timing differences in a verbal dichotic listening condition but not in a noise control condition. Hence, this association between callosal microstructure and between-hemisphere timing differences is specific for stimuli, which trigger hemispheric bottom-up processing in an asymmetric fashion. Specifically, higher microstructural integrity was associated with decreased left-right differences in the latency of the N1 event-related potential component and hence more symmetric processing of dichotic stimuli between the two hemispheres. Our data suggest that microstructure of the posterior callosal third affects functional hemispheric asymmetries by modulating the timing of interhemispheric interactions.
- MeSH
- corpus callosum fyziologie MeSH
- dospělí MeSH
- elektroencefalografie MeSH
- funkční lateralita fyziologie MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- zobrazování difuzních tenzorů MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Patofyzioiogickým podkladem narkolepsie-kataplexie je ztráta hypokretinových neuronů posterolaterálního hypotalamu. Předpokládaným projevem tohoto deficitu je změna mikrostruktury a autonomních funkcí ve spánku u těchto pacientů. Cílem studie bylo hodnocení mikrostruktury NREM (non-rapid eye movement) spánku metodou sledování cyklických alternujících vzorců (CAP) a změny variability srdeční frekvence (HRV). Do studie bylo zahrnuto 15 pacientů s narkolepsiíkataplexií (průměrný věk 35 8,5 věkové rozmezí 22-44 let) a 15 zdravých kontrol (31 ± 11,4; 19-48 let). Obě skupiny podstoupily 2 následná polysomnografická vyšetření, pro analýzu CAP a HRV byla zpracována data ze 2. noci. Prokázali jsme signifikantní snížení CAP, provázené sníŽením LF a zvýšením HF složky při redukci poměru LF/HF v průběhu NREM spánku. Výsledky vyjadřují poruchu kolísání prahu probuzení u narkolepsie-kataplexie, která je provázena redukcí tonu sympatiku během NREM spánku. Domníváme se, narkolepsie nevzniká pouze v důsledku poruchy regulace REM spánku, nýbrž že je současně vlivem deficientní hypokretinové modulace alt porušena i regulace NREM spánku.
The present study was aimed at analysing the non-rapid eye movement (NREM) sleep microstructure by the cyclic alternating pattern (CAP) and at assessing the heart rate variability (HRV) changes in patiens with narcolepsy, hypothesizing a correlation of an abnormal sleep microstructure and abnormal autonomic response with a selective loss of hypocretin-containing neurons in narcolepsy. Fifteen patients with narcolepsy-cataplexy (mean age 35±8.5; age range 22-44), and 15 age and sex matched controls (mean age 31±11.4; age range 19-48) were included in the study. All subjects underwent polysomnography recordings for two consecutive nights in a standard laboratory setting. The sleep scoring was focused on the CAP and HRV analysis. A significant decrease in CAP rate as well as significant reduction of the LF spectral band and the LF/HF ratio, and the elevation of the HF spectral component during NREM 4 stage were revealed in narcoleptics compared to controls. Our results suggest that physiological fluctuation of arousal during sleep described as CAP is impaired in narcolepsy and accompained by reduced sympathetic tone during SWS. We have hypothesized that the whole sleep regulation process is altered in narcolepsy and not only REM sleep mechanisms.
- MeSH
- elektroencefalografie metody využití MeSH
- finanční podpora výzkumu jako téma MeSH
- interpretace statistických dat MeSH
- lidé MeSH
- narkolepsie diagnóza etiologie MeSH
- neuropeptidy nedostatek MeSH
- poruchy spánku a bdění diagnóza etiologie patofyziologie MeSH
- spánek REM fyziologie MeSH
- srdeční frekvence fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
