Effects Of Morphological Changes Research Articles

Assessment of the Effects of Morphological Changes Related to Age-Related Macular Degeneration on Optical Coherence Tomography Retinal Thickness Measurements

Age-related macular degeneration (AMD) leads to morphological changes that can interfere with optical coherence tomography retinal thickness measurements. The effects of AMD on two available retinal thickness scan modes were tested. Ninety-four scans, equally divided into Radial Line Scans (RLS) and Fast Macula Scans (FMS), of 42 patients with AMD were reviewed. Patients were graded into 4 categories regarding AMD severity. Each scan mode was evaluated for each AMD category. In dry moderate AMD, 2% of the RLS and 5% of the FMS thickness measurements failed. In dry progressed AMD, the RLS mode performed better (26% failure rate) than the FMS mode (42% failure rate). However, in exudative AMD the FMS mode performed better (6% failure rate) than the RLS mode (28% failure rate). The difference between the RLS and FMS performance in dry progressed AMD compared with exudative AMD was significant (P < .0001). The optical coherence tomography retinal thickness scan modes perform differently, depending on AMD severity. Retinal thickness algorithms with better performance are needed to facilitate measurements in patients with AMD.

Morphology and transport properties of protons and methanol through partially sulfonated block copolymers

The morphological changes with different compositions of casting solvents in the membranes of sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) were investigated with small-angle X-ray scattering (SAXS) and transmission electron microscope (TEM). Using the single solvent of tetrahydrofuran (THF) and the solvent mixtures of methanol/THF with different compositions, the casting polymer solutions were prepared for the membrane fabrication. The proton conductivity and the methanol permeability of membranes were measured, and the effect of morphological changes on the casting solvents was discussed through Flory–Huggins theory. It was found that the sulfonated SEBS membranes were transformed from well ordered lamellar to disordered co-continuous structure and the morphological difference caused abrupt enhancement in the proton conductivity and the methanol permeability as the concentration of methanol in the mixed solvents (MeOH/THF) increased.

Causes and effects of morphological changes of the regulated channel of the river Toplica

The regulation of small torrential watercourses outside the urbanized areas is often based on the so-called field type of regulation. In the selection of this concept, after the regulation works, the new channel is left to the natural process of the morphological formation of the water cross-section taking care not to disturb the general stability of the regulated channel. We present the process of morphological development of the regulated channel of the river Toplica, tributary of the river Kolubara, in the period 1982-2004 i.e. from immediately after the regulation works to the present day.

Partially Sulfonated Polystyrene and Poly(2,6‐dimethyl‐1,4‐phenylene oxide) Blend Membranes for Fuel Cells

AbstractSummary: Based on Flory–Huggins parameters (χ), the miscibility and the effect of morphological change on proton conductivity and methanol permeability of partially sulfonated polystyrene (SPS) and partially sulfonated poly(2,6‐dimethyl‐1,4‐phenylene oxide) (SPPO), having an identical ion exchange capacity, were investigated. When 50 wt.‐% of SPPO was blended, both the proton conductivity and methanol permeability had the highest values, which resulted from the change of amorphous domains and the hydrogen bonding between the two ionomers.The proton conductivities, water uptake and methanol permeability for the SPPO/SPS blend membranes studied here. The membranes with 50 wt.‐% SPPO clearly showed the greatest increase in these properties.imageThe proton conductivities, water uptake and methanol permeability for the SPPO/SPS blend membranes studied here. The membranes with 50 wt.‐% SPPO clearly showed the greatest increase in these properties.

The effect of morphological changes from pulp fiber towards nano-scale fibrillated cellulose on the mechanical properties of high-strength plant fiber based composites

Fibrillated kraft pulp impregnated with phenolic resin was compressed under an extremely high pressure of 100 MPa to produce high strength cellulose nanocomposites. To evaluate how the degree of fibrillation of pulp fiber affects the mechanical properties of the final composites, kraft pulp subjected to various levels of refining and high pressure homogenization treatments was used as raw material with different phenolic resin contents. It was found that fibrillation solely of the surface of the fibers is not effective in improving composite strength, though there is a distinct point in the fibrillation stage at which an abrupt increase in the mechanical properties of composites occurs. In the range between 16 and 30 passes through refiner treatments, pulp fibers underwent a degree of fibrillation that resulted in a stepwise increment of mechanical properties, most strikingly in bending strength. This increase was attributed to the complete fibrillation of the bulk of the fibers. For additional high pressure homogenization-treated pulps, composite strength increased linearly against water retention values, which characterize the cellulose’s exposed surface area, and reached maximum value at 14 passes through the homogenizer.

Clonal variation in the thermal response of the submerged aquatic macrophyte Potamogeton pectinatus

Summary Broadly distributed plants have to cope with dramatic differences across latitude in the prevailing environmental temperature. We investigated the effect of water temperature on plant morphology, biomass accumulation and oxygen‐exchange for five clones of the submerged aquatic macrophyte Potamogeton pectinatus L., originating from 42 to 68°N. We tested whether P. pectinatus clones show local adaptation to the prevailing environmental temperatures (in which case high‐latitude clones would perform better at lower temperatures and vice versa). Alternatively, pronounced phenotypic plasticity in the response to temperature could enable individual clones to perform well over a wide range of environmental temperatures (i.e. high degree of thermal tolerance). The overall pattern of thermal response was similar for all clones. In addition, we detected acclimative phenotypic plasticity in both physiological and morphological plant parameters. The optimum temperatures for gross or for net photosynthesis did not vary with growth temperature, but morphological acclimation partly compensated for the loss of photosynthetic capacity at higher temperatures, enabling comparable rates of ambient gross photosynthesis. Respiratory reactions also showed some degree of thermal acclimation to higher temperatures. As a result of the combined effects of changes in morphology and physiology, all clones produced similar amounts of plant biomass over a relatively wide range of water temperatures. We therefore conclude that P. pectinatus is thermally tolerant and not locally adapted.

Effects of morphological changes on metal accumulation in a salt marsh sediment of the Skallingen peninsula, Denmark

In 1931 a red-colored, sandy marker horizon was placed on the emergingSkallingen salt marsh. Sedimentation on top of the marker horizon sincethen shows two opposing tendencies. Coincident with salt marshdevelopment the sediments display up to 1964 a fining upward sequencewith an increasing content of organic matter. Since 1964 a nearby creekhas meandered towards the sampling plot. Consequently, the sedimentsbecome coarser with a decreasing organic matter content. Themorphological induced changes in sedimentary conditions strongly influencemetal content in the sediments and thereby hide anthropogenic inducedconcentration variations. Thus, an apparently diminishing Zn content (perkg dry weight) since 1964 could indicate lesser load to the area. However,corrected for grain size effects there is an increasing content of Zn. Othermetal concentrations (e.g. Cu) show a diminishing trend when corrected forgrain size effects and therefore indicate a reduced anthropogenic inducedload of these metals to the salt marsh.

SUITABILITY CRITERIA FOR FISHES FOCUSING ON SEASONAL CHANGE OF FISH HABITAT

PHABSIM is one of the most famous methods to estimate condition of fish habitat. Recently many researches are performed to improve PHABSIM. In this study we derived the criteria for habitat of Japanese dace (Tribolodon hakonensis). At first, we paid attention to the seasonal change of Japanese dace's habitat. Japanese dace utilized a different area in each season, but the local condition of depth and velocity was approximately constant all the year round. So we clarified that the neig hboring condition affects the condition of fish habitat. Next, we evaluated the effect of morphological changes on the fish habitat, and we clarified that flattening of sand bars and local incisions of riverbed cause the degradation of fish habitat. So we improved original PHABSIM to estimate the morphological impacts, and suggested the new suitability criteria of Japanese dace based on rapid-pool conditions.

The effects of morphological changes and mineral matter on H2S evolution during coal pyrolysis

The H2S release profiles of five important Colombian coals have been monitored using temperature programmed pyrolysis. It was found that there was no correlation between the amount of H2S and the sulphur content of the original coals. Coals which had been treated to remove all of the mineral matter and inorganic sulphur showed a good correlation with the free swelling index of the coals. This was explained by the physical trapping of H2S in closed porosity formed during pyrolysis. A similar result was found for demineralised coals with pyrite present. The H2S for untreated coals showed no systematic variation with rank, the coal sulphur content or free swelling index. This was because certain coals were rich in finely dispersed calcium which could chemically prevent H2S release.

Effects of Morphological Changes of Pt/SrBi2Ta2O9 Interface on the Electrical Properties of Ferroelectric Capacitor

Morphological changes have been observed at the interface of Pt/SrBi2Ta2O9 (SBT) before and after annealing at 600 and 800°C after depositing Pt top electrode. We have investigated leakage currents, breakdown voltages, and capacitances of Pt/SBT/Pt /SiO2/Si capacitor and Pt/SBT/CeO2/Si gate structure. As a result, the leakage current density and capacitance are reduced from 10-7 to 10-8 A/cm2 and 1.3×10-10 to 8.5×10-11 F/cm2, respectively, and breakdown voltage increases from 5 to 14 V after post-annealing. The reduced leakage current density and increased breakdown voltage in the annealed samples are due to the smooth morphology of the interface of Pt/SBT. In the as-deposited Pt top electrode on SBT films, high electric field intensity is generated due to small arc of the valleys filled with fine Pt grains, resulting in higher leakage current density than the post-annealed Pt top electrode. Although the total gate capacitance of the post-annealed sample is reduced by the non-contact area due to voids at the interface of Pt/SBT, memory window of the ferroelectric gate is not influenced by such voids.

Effects of morphological changes on the oxygen transport properties of poly[(ethylene terephthalate)‐co‐(1,4‐cyclohexylene dimethylene terephthalate)

AbstractTo improve the physical picture of the polymeric glassy state, the influence of morphological changes achieved by different thermal treatments of an amorphous glassy poly(alkylene terephthalate) film on the oxygen transport properties has been studied. Annealing treatments were performed on films in constraint imposed giving samples of different crystallinity contents and morphology.The dependence of the oxygen permeability and diffusion as the free volume from crystallinity content was investigated at sub‐Tg temperatures within the range of 303–348 K.The investigations reveal that on crystallized samples, permeability and solubility coefficients decrease at higher crystallization temperature, while annealed samples showed an opposite trend despite higher crystallinities. Further, annealed films showed higher free volume content.The trend of results suggests that different parameters are likely to play a significant role in determining apparent permeability coefficients. The presence of microvoids in annealed samples may be supposed.

The effect of morphological changes on the coprecipitation of strontium by calcium phosphate

The coprecipitation of strontium by a calcium phosphate phase formed at an elevated pH 10.8 was investigated. The first phase obtained under these conditions in the amorphous calcium phosphate (ACP) which is transformed into crystalline hydroxyapatite (HA) after the induction period. Is has been shown that this transformation together with morphological changes of the precipitated solid phase, influences the amount of the sorbed strontium significantly. The possible consequences of this finding on practical application of coprecipitation of strontium by calcium phosphate have been discussed.

Protease production in continuous culture by Aspergillus oryzae: effect of morphological changes of mycelia on resistance against shear force

Protease production in continuous culture by Aspergillus oryzae: effect of morphological changes of mycelia on resistance against shear force

The ontogeny of functional design: metamorphosis of feeding behaviour in the tiger salamander (Ambystoma tigrinum)

The ontogeny of feeding behaviour was studied quantitatively in the tiger salamander, Ambystoma tigrinum, to elucidate the relative importance of morphological and environmental changes on form and function. High‐speed films of prey capture provided data for a frame‐by‐frame analysis of seven kinematic parameters of feeding behaviour. By comparing underwater feeding of larval and metamorphosed individuals, the effect of morphological changes occurring at metamorphosis on the feeding kinematic pattern was determined. By comparing metamorphosed animals feeding in the water and on land, changes in feeding kinematics associated with the environmental transition (and thus the differing physical properties of water and air) were determined. Both univariate and multivariate analyses failed to demonstrate any differences between larval and metamorphosed aquatic feedings for seven kinematic variables. However, when individuals feed on land, a radical shift in hyoid kinematics was observed. In addition, multivariate analysis showed that terrestrial feedings differed from aquatic feedings in having longer duration head movements. The lack of a kinematic difference between larval and metamorphosed individuals feeding in the water indicates that the morphological changes occurring at metamorphosis do not impose any obligatory kinematic consequences. Rather, metamorphosed Ambystoma tigrinum acquire the ability to modulate their kinematic pattern depending on the environment.

Chaoborus predation and the function of phenotypic variation in Daphnia

To investigate the role of helmet formation in defense against predation, laboratory experiments were used to analyze the effects of morphological changes in Daphnia on susceptibility to Chaoborus predation. Behavioral observations of Chaoborus preying on helmeted and non-helmeted Daphnia suggest pre-contact advantages for helmeted prey but post-contact advantages for non-helmeted prey. Helmeted Daphnia are better at evading capture by Chaoborus but may also be more easily handled by the predator. Swimming behavior of the prey, which is influenced by the presence of a tailspine, may affect Chaoborus strike distance. These results re-emphasize the potential hydromechanical importance of body shape changes in defense against predation.

連続焼鈍軟質冷延鋼板の微細炭化物析出形態と延性

連続焼鈍軟質冷延鋼板の微細炭化物析出形態と延性