Acrylonitrile-butadiene-styrene toughened nylon 6: The influences of compatibilizer on morphology and impact properties

Polymer alloys have been used as an alternative to obtain polymeric materials with unique physical properties. Generally, the polymer mixture is incompatible, which makes it necessary to use a compatibilizer to improve the interracial adhesion. Nylon 6 (PA6) is an attractive polymer to use in engineering applications, but it has processing instability and relatively low notched impact strength. In this study, the acrylonitrile-butadiene-styrene (ABS) triblock copolymer was used as an impact modifier for PA6. Poly(methyl methacrylate-co-maleic anyhydride) (MMA-MA) and poly(methyl methacrylate-co-maleic methacrylate) (MMA-GMA) were used as compatibilizers for this blend. The morphology and impact strength of the blends were evaluated as a function of blend composition and the presence of compatibilizers. The blends compatibilized with maleated copolymer exhibited an impact strength up to 800 J/m and a morphology with ABS domains more efi8ciently dispersed. Moderate amounts of MA functionality in the compatibilizer (∼5%) and small amounts of compatibilizer in the blend (∼5%) appear sufficient to improve the impact properties and ABS dispersion. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87.

Morphology and histoenzymology of eosinophilic granulocytes in the circulating blood of the turtle (Chrysemys dorbignih)

The studies on the characterization of eosinophils and neutrophils/ heterophils of turtles are contradictory. Some authors have pointed out the existence of two distinct cell types: eosinophils and heterophils. Other authors have proposed that eosinophils and heterophils may be the same cells in different stages of maturation. These interpretations are based only on a morphological analysis. In the blood of the turtle (Chrysemys dorbignih), a South American freshwater species, there are two types of granulocytes with eosinophilic staining pattern: the first with round cytoplasmic granules and the second with ellipsoidal cytoplasmic granules. In the present study by using histoenzymological methods for the analyses of enzymological cellular content, we found that the cells with round cytoplasmic granules were positive for nonspecific esterase and the cells with ellipsoidal granules were positives for acid phosphatase, alkaline phosphatase, nonspecific esterase and peroxidase. The results show that these cells are distinct cells and that the cells with ellipsoidal cytoplasmic granules have the same histoenzymological characteristics as the neutrophils/heterophils of mammalians and other vertebrates.

Root instrumentation with an erbium:yttrium-aluminum-garnet laser: Effect on the morphology of fibroblasts

Objective: The purpose of this study was to evaluate the effect of erbium:yttrium-aluminum-garnet laser instrumentation of root surfaces on the morphology of fibroblasts from continuous lineage. Method and materials: Dentinal slices with 4 mm2 of surface area were obtained from teeth extracted for severe periodontal involvement. Specimens were assigned to one of three treatment groups: group 1, application of the laser with an energy level of 250 mJ at 103 pulses per second; group 2, application of the laser with an energy level of 80 mJ at 166 pulses per second; and group 3, similar to group 2, but with concomitant water irrigation of the device. The specimens were incubated in multiwell plates containing cell culture media. After 24 hours, the specimens were submitted to routine preparation for scanning electron microscopy. Three independent and blind examiners used photomicrographs to evaluate the morphology of the fibroblasts: 0 = without cells; 1 = flat cells; 2 = round cells; and 3 = combination of round and flat cells. Results: Statistical analysis indicated that there were significant differences among treatment groups and that group 3 was significantly different from groups 1 and 2. Conclusion: There was no difference between groups 1 and 2 in the morphology of fibroblasts. Laser instrumentation with concomitant irrigation impaired the adhesion of fibroblasts to dentinal surfaces.

Morphology of the vas deferens of the budgerigar (Melopsittacus undulatus)

A morphological study of the budgerigar vas deferens was conducted to demonstrate the electron-microscopic features of its epithelial lining. The analysis showed that the vas deferens of the budgerigar was found to be of a tubular and serpentine structure, continuous with the epididymal region and lined with stereo ciliated pseudostratified epithelium, which contained folds projecting into the tubular lumen and a characteristic brush border. The epithelium consists of ciliated and non-ciliated cells with different electron densities. Ciliated cells were characterized by two morphologically distinct configurations: some cells were columnar and other ciliated cells were longer, thinner and dark. Non-ciliated cells showed apical cytoplasmic expansions, which projected into the tubular lumen as protrusions.

Morphology changes induced by laser irradiation on disperse red 13 films prepared by physical vapor deposition

Surface morphology changes induced by argon laser irradiation (514 nm) on disperse red 13 (DR13) films prepared by physical vapor deposition (PVD) were investigated. Atomic force microscopy was used to characterize the irradiated sample for different periods of irradiation. Needle-shape structures are observed which are attributed to the symmetry of DR13 molecules. The film becomes increasingly closely packed with the irradiation, with lower root mean square roughness for long exposure times. This is due to photoisomerization of DR13 molecules and probably heating of the sample, which can provide the required mobility for the molecular rearrangement. The rearrangement is such that voids in the film are filled in upon irradiating the sample, thus decreasing the film roughness and increasing the packing.

Morphology of the vas deferens in an ethanol-drinking strain of rats (UChA and UChB)

Chronic alcoholism alters reproduction and therefore may be responsible for alterations of vas deferens, which are the subject of this analysis in UCh ethanol-drinking rats. The proximal and distal segments of the vas deferens of 20 animals were submitted to macroscopic, light microscopy, electron microscopy and morphometric analysis. The UCh rats showed atrophy of the epithelium of the vas deferens and alterations of the hypothalamus-pituitary axis. Ethanol induces changes in the epithelium of the vas deferens and hypothalamus-pituitary axis of UCh rats.

Effect of air-powder system on titanium surface on fibroblast adhesion and morphology.

PURPOSE: To evaluate the number and morphology of fibroblasts grown on machined titanium healing abutments treated with an airpowder system. MATERIALS AND METHODS: Twenty-six abutments were assigned to two experimental groups: control (no treatment) and treated (exposed to the Prophy-Jet for 30 seconds). The specimens were incubated for 24 hours with fibroblastic cells in multiwell plates, followed by routine laboratory processing for scanning electron microscope analysis. The specimens were photographed at x 350, and the cell number was counted on an area of approximately 200 um2. RESULTS: No significant differences were found on morphology between the groups (P > 0.05); however, the control group presented a significantly greater amount of cells (71.44 +/- 31.93, mean +/- SD) in comparison with treated group (35.31 +/- 28.14), as indicated by a nonpaired t test (P = 0.001). CONCLUSION: The use of an air-abrasive prophylaxis system on the surface of titanium healing abutments reduced the cells proliferation but did not influence cell morphology.

Influence of the labial gland's semiochemicals on the feeding behavior of Coptotermes havilandi (Isoptera: Rhinotermitidae)

In termites, food search is mediated by semiochemicals that are liberated by exocrine glands. In the present work we investigated the effect of the secretion of the labial glands of workers on the feeding behavior of Coptotermes havilandi. The secretion of the labial glands exhibited phagostimulant effect on the workers of this species. The soldiers showed a low activity in response to the labial gland extracts suggesting that this gland's secretion might inhibit the recruitment of soldiers. Behavioral evidence for the regulation of food consumption by workers was observed.

Morphology of Nylon 6/Acrylonitrile-Butadiene-Styrene Blends Compatibilized by a Methyl Methacrylate/Maleic Anhydride Copolymer

The morphologies of nylon 6/acrylonitrile-butadiene-styrene blends compatibilized with a methyl methacrylate/maleic anhydride copolymer, with 3-20 wt % maleic anhydride, were examined by transmission electron microscopy. Some staining techniques were employed for identifying the various phases. The binary blends were immiscible and exhibited poor mechanical properties that stemmed from the unfavorable interactions among their molecular segments. This produced an unstable and coarse phase morphology and weak interfaces among the phases in the solid state. The presence of the copolymer in the blends clearly led to a more efficient dispersion of the acrylonitrile-butadiene-styrene phase and consequently optimized Izod impact properties. © 2003 Wiley Periodicals, Inc.

The influence of fruit morphology and habitat structure on ant-seed interactions: A study with artificial fruits

Artificial fruits designed to simulate lipid-rich non-myrecochorous diaspores were used to test for the effect of fruit morphology and habitat structure on ant-seed interactions in an Atlantic Forest site in SE Brazil. The outcome of the interaction (i.e., if the fruit was removed, cleaned by ants on the spot or had no interaction with ants) and the time of ant response were the investigated variables. Models simulating drupes and arilate diaspores were used to test for morphological effects and four habitat attributes (litter depth, number of logs, number of trees, and percentage of bromeliad coverage on the forest floor), likely to be correlated with the ant diversity and abundance in the study site, were measured to test for the effect of habitat structure. The proportion of fruits removed or cleaned did not differ between the two morphological models. Sites in which fruits were cleaned had more trees than those in which no interaction occurred. This may be a result of the foraging behavior of arboreal ants that frequently descend to the forest floor to exploit fleshy diaspores. Sites in which model removal occurred had lower litter depth than both those in which models were cleaned and those in which no interaction occurred. A negative correlation was observed between litter depth and ant response time. Accumulation of leaf litter at a given point may have constrained the movements of large ants in general, and ponerine ants (that are important seed removers) in particular. We conclude that that local pattern in litter depth and tree density influence the frequency and outcome of interactions between ants and non-myrmecochorous, fleshy diaspores.

Morphology and protein patterns of honey bee drone accessory glands.

We used light and transmission electron microscopy to examine the morphology of the accessory glands of immature and mature adult males of Apis mellifera L. We also made an electrophoretic analysis of the protein content of the mature gland. The glands of the immature male actively secrete a mucous substance that can be seen in the lumen of the gland of the mature male. This secretion stains with mercury bromophenol blue and with periodic acid-Schiff reaction, which stain glyconjugates. The protein content was higher in the lumen secretion than in the gland wall extracts. The electrophoresis patterns of the wall extracts were different from those of the secretion found in the gland lumen.

Influence of the processing conditions and corona poling on the morphology of β-PVDF

The α → β phase transformation of PVDF through the stretching process at different temperatures was investigated. The optimum stretching conditions were studied and characterised by infrared spectroscopy and differential scanning calorimetry. The maximum β-phase content was achieved at 80°C and a stretch ratio of 5. These samples were poled at several electric fields by the corona charge method. The effect of the electric field on the phase transformation was studied by infrared spectroscopy.

Morphology of oesophagus and crop of the partrigde Rhynchotus rufescens (Tiramidae)

Twenty adult partridges Rhynchotus rufescens were used to study the morphology of oesophagus and crop. Materials to the morphologic study were collected and lengths of the oesophagus and of the crop were measured. For histological study, fragments of the oesophagus and of the crop were stained routinely with Masson's trichrome stain. Total oesophagus was larger in females. In the entrance of the thorax, its ventral wall is enlarged broadly, forming the crop, which is larger in males. Oesophagus mucosa is constituted by stratified squamous epithelium, with mucous glands and lymphatic tissues. There are three layers of smooth muscle, involved in serosa. The histological structure of the crop is similar to the oesophagus. The mucous glands are reduced in size and the lymphatic tissues are dispersed in the connective tissue. There is a thin stratum of smooth muscle and other two wider layers of longitudinal and circular musculature.

Additional observations on the gross morphology and microstructure of Baccaconularia Hughes, Gunderson et Weedon, 2000, a Cambrian (Furongian) conulariid from the north-central USA

Baccaconularia Hughes, Gunderson et Weedon, 2000, from the Furongian Series (Cambrian System) of the north-central USA, has been interpreted as a conulariid cnidarian, based on a suite of gross morphological similarities shared only with other post-Cambrian genera currently assigned to this group. Closely spaced, squarish to subrectangular facial nodes of Baccaconularia are aligned in distinct longitudinal files. Nodes also display a subtler, more or less rectilinear transverse alignment, though this pattern commonly is disrupted by offset parallel to the longitudinal files. In their shape and pattern of arrangement, the nodes of Baccaconularia are most similar to the squarish to elongate nodes of Pseudoconularia Bouček, 1939. Longitudinal node files of Baccaconularia may also be compared with the longitudinal facial ridges of Conularia cambria Walcott, 1890 from the Furongian of Wisconsin. Apical angles of Baccaconularia range from approximately 13° to 14.5°. Scanning electron imaging of B. cf. robinsoni shows that its thin, phosphatic skeleton is finely lamellar, with the thickness of individual lamellae measuring approximately 1 μm. The skeleton also exhibits microscopic circular pores and crater-like pits that range from approximately 5 to 10 μm in diameter. These pores and pits are similar in size, geometry, areal density and pattern of arrangement to those of many post-Cambrian conulariids. Microscopic circular pores are documented here for the first time in the genus Archaeoconularia Bouček, 1939 from the Upper Ordovician of the Czech Republic. Although the origin of the pores and pits is open to alternative interpretations, the discovery of these features and fine lamination in Baccaconularia strengthens the argument that this genus is a Cambrian conulariid. © 2006 Nanjing Institute of Geology and Palaeontology, CAS.