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Total Surface Area (total + surface_area)
Selected AbstractsCombined Confocal Microscopy and Stereology: a Highly Efficient and Unbiased Approach to Quantitative Structural Measurement in TissuesEXPERIMENTAL PHYSIOLOGY, Issue 6 2002Katherine Howell Understanding the relationship of the structure of organs to their function is a key component of integrative physiological research. The structure of the organs of the body is not constant but changes, both during growth and development and under conditions of sustained stress (e.g. high altitude exposure and disease). Recently, powerful new techniques have become available in molecular biology, which promise to provide novel insights into the mechanisms and consequences of these altered structure-function relationships. Conventionally structure-function relationships are studied by microscopic examination of tissue sections. However, drawing conclusions about the three-dimensional structure of an organ based on this two-dimensional information frequently leads to serious errors. The techniques of stereology allow precise and accurate quantification of structural features within three-dimensional organs that relate in a meaningful way to integrated function. For example, knowledge of changes in the total surface area of the capillary endothelium in an organ can be related directly to changes in fluid filtration and permeability, or knowledge of total vessel length and mean radius allows deductions about vascular resistance. Confocal microscopy adds enormously to the power of stereological approaches. It reduces the difficulties and labour involved in obtaining suitable images. Moreover, when used in conjunction with new analytical software, it allows convenient application of stereology to small samples and those in which it is essential to maintain a specific orientation for interpretation. The information obtained will allow us to examine in a quantitative manner the altered structure-function relationships produced by manipulation of single genes and regulatory pathways in whole organisms. [source] A quantitative morphological analysis of nanostructured ceria,silica composite catalystsJOURNAL OF MICROSCOPY, Issue 2 2008M. MOREAUD Summary This study aims at examining the morphology of different catalysts, which are based on a dispersion of ceria nanoparticles embedded in a high surface area mesoporous silica framework. In order to fully describe the mesostructured composite material, we propose here a quantitative description of the microstructure based on a quantitative analysis of micrographs that were obtained via high-resolution transmission electron microscopy. We have therefore developed an automatic image analysis process in order to automatically and efficiently extract all the components of the catalyst images. A statistical and a morphological analysis of the spatial arrangement of the components of the catalyst are also presented. The study shows clear differences between the materials analysed in terms of the spatial arrangement and the total surface area of the ceria phase emerging into the pores, parameters of prime importance for the catalytic properties. Thus, the silica,ceria nanostructured composite materials, displaying large surface area up to 300 m2 g,1 are shown to exhibit highly rugged surfaces resulting from ceria nanoparticles emerging in the pores. [source] Nanocomposite Formation Through Thermal Decomposition of Mixed Samarium and Magnesium Citrate-Derived Gels Formed by Spray PyrolysisJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 9 2008Thorsten Enz Metal citrate gels of samarium and magnesium were used as precursors for the generation of hollow sphere particles by spray pyrolysis under mild thermal conditions. Six mixtures with different Sm/Mg ratios as well as pure Sm and Mg samples were prepared. As a result of the low synthesis temperature the particles consist of amorphous metal carboxylate networks. The texture of the shells is governed by microporosity yielding the major part of the total surface area. A detailed investigation of thermal decomposition, crystallization, and grain growth behavior was carried out under constant heating rate conditions. The decomposition products are nanocrystalline Sm2O3 and MgO and corresponding two-phase nanocomposites. The pure samarium carboxylate gel features considerably higher thermal stability compared with the one comprised of only magnesium. Accordingly the decomposition behavior of mixed samples is dependent on the Sm/Mg ratio. Furthermore it is shown that small amounts of MgO are able to slow down the kinetics of grain growth of Sm2O3 whereas high amounts are necessary to significantly reduce the final grain size at 1000°C. [source] Formation of Two Kinds of Hexagonally Arranged Structures in ABC Triblock Copolymer Thin Films Induced by a Strongly Selective Solvent VaporMACROMOLECULAR RAPID COMMUNICATIONS, Issue 22 2009Chunxia Luo Abstract An order,order transition (OOT) in the sequence of a hexagonally arranged core,shell cylinder to a double-hexagonally arranged dot in polystyrene- block -poly(butadiene)- block -poly(2-vinylpyridine) (SBV) triblock copolymer thin films is reported to be induced upon exposure to a solvent vapor that is strongly selective for the two end blocks. These two kinds of hexagonally arranged structures could form when the film thickness is 44, 123, and 223,nm. When the film thickness is decreased to 13,nm, the ordered structure is absent. The sizes of the core,shell cylinder structures formed with the same annealing time in films of different thickness are compared to address the effects of film thickness on the phase structure. The mechanism is analyzed from the total surface area of the blocks and the effective interaction parameter in the solvent vapor. [source] Selecting the right compounds for screening: use of surface-area parametersPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 3 2002Colin M Tice Abstract Polar surface area, total surface area and percentage surface area have been calculated from three-dimensional structures of 88 post-emergence herbicides, 93 pre-emergence herbicides and 237 insecticides. Preferred ranges of values of these parameters were identified. Since the compounds in the training sets are used on a wide variety of species and target sites with various application modes, the parameter ranges are necessarily broad. The utility of the surface-area parameter ranges in selection of compounds for agrochemical screening was compared with the use of ranges of the Lipinski Rule of 5 parameters: molecular mass, calculated log P, number of hydrogen-bond donors and number of hydrogen-bond acceptors. The more computationally intensive surface-area parameters did not offer any obvious advantage over the Lipinski Rule of 5 parameters. © 2002 Society of Chemical Industry [source] Scaling of the first ethmoturbinal in nocturnal strepsirrhines: Olfactory and respiratory surfacesTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 3 2007Timothy D. Smith Abstract Turbinals (scroll bones, turbinates) are projections from the lateral wall of the nasal fossa. These bones vary from simple folds to branching scrolls. Conventionally, maxilloturbinals comprise the respiratory turbinals, whereas nasoturbinals and ethmoturbinals comprise olfactory turbinals, denoting the primary type of mucosa that lines these conchae. However, the first ethmoturbinal (ETI) appears exceptional in the variability of it mucosal covering. Recently, it was suggested that the distribution of respiratory versus olfactory mucosae varies based on body size or age in strepsirrhine primates (lemurs and lorises). The present study was undertaken to determine how the rostrocaudal distribution of olfactory epithelium (OE) versus non-OE scales relative to palatal length in strepsirrhines. Serially sectioned heads of 20 strepsirrhines (10 neonates, 10 adults) were examined for presence of OE on ETI, rostral to its attachment to the nasal fossa wall (lateral root). Based on known distances between sections of ETI, the rostrocaudal length of OE was measured and compared to the length lined solely by non-OE (primarily respiratory epithelium). In 13 specimens, the total surface area of OE versus non-OE was calculated. Results show that the length of non-OE scales nearly isometrically with cranial length, while OE is more negatively allometric. In surface area, a lesser percentage of non-OE exists in smaller species than larger species and between neonates and adults. Such results are consistent with recent suggestions that the olfactory structures do not scale closely with body size, whereas respiratory structures (e.g., maxilloturbinals) may scale close to isometry. In primates and perhaps other mammals, variation in ETI morphology may reflect dual adaptations for olfaction and endothermy. Anat Rec, 2007. © 2007 Wiley-Liss, Inc. [source] Novel Imaging Analysis System to Measure the Spatial Dimension of Engineered Tissue ConstructARTIFICIAL ORGANS, Issue 2 2010Kyoung-Hwan Choi Abstract The measurement of the spatial dimensions of tissue-engineered constructs is very important for their clinical applications. In this study, a novel method to measure the volume of tissue-engineered constructs was developed using iterative mathematical computations. The method measures and analyzes three-dimensional (3D) parameters of a construct to estimate its actual volume using a sequence of software-based mathematical algorithms. The mathematical algorithm is composed of two stages: the shape extraction and the determination of volume. The shape extraction utilized 3D images of a construct: length, width, and thickness, captured by a high-quality camera with charge coupled device. The surface of the 3D images was then divided into fine sections. The area of each section was measured and combined to obtain the total surface area. The 3D volume of the target construct was then mathematically obtained using its total surface area and thickness. The accuracy of the measurement method was verified by comparing the results with those obtained from the hydrostatic weighing method (Korea Research Institute of Standards and Science [KRISS], Korea). The mean difference in volume between two methods was 0.0313 ± 0.0003% (n = 5, P = 0.523) with no significant statistical difference. In conclusion, our image-based spatial measurement system is a reliable and easy method to obtain an accurate 3D volume of a tissue-engineered construct. [source] Ultraviolet reflectance and cryptic sexual dichromatism in the ocellated lizard, Lacerta (Timon) lepida (Squamata: Lacertidae)BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2009ENRIQUE FONT Ultraviolet (UV) colorations have garnered extensive theoretical and empirical treatment in recent years, although the majority of studies have concerned themselves with avian taxa. However, many lizards have acute visual systems with retinal photoreceptors that are sensitive to UV wavelengths, and also display UV-reflecting colour patches. In the present study, we used UV photography and full-spectrum reflectance spectrophotometry to describe intra- and intersexual colour variation in adult ocellated lizards Lacerta (Timon) lepida and to obtain evidence of UV-based ornamentation. We also investigated whether any colour traits correlate with morphological traits potentially related to individual quality. The results obtained show that the prominent eyespots and blue outer ventral scales (OVS) that ocellated lizards have on their flanks reflect strongly in the UV range and are best described as UV/blue in coloration. The eyespots of males are larger and cover a larger surface area than those of females. However, these differences can be entirely accounted for by sex differences in body size, with males being generally larger than females. We also found differences in the shape of reflectance curves from males and females, with the eyespots and blue OVS of males being more UV-shifted than those of females. Other body regions have extremely low UV reflectance and are not sexually dichromatic. Eyespot size and the total surface area covered by eyespots increases with body size in males but not in females, suggesting that they may be signalling an intrinsic individual characteristic such as body size or male fighting ability. We also discuss the alternative and non-exclusive hypothesis that eyespots may function in lizards of both sexes as protective markings against predators. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 766,780. [source] | ||||||||||||||||