Small Protuberances Research Articles

Isothermal Growth and Reorganization upon Heating of a Single Poly(aryl−ether−ether−ketone) (PEEK) Spherulite, As Imaged by Atomic Force Microscopy

We have studied by atomic force microscopy (AFM, topographical imaging) the evolution of a single PEER spherulite in a thin film during isothermal cold-crystallization and upon subsequent reheating to increasingly higher temperatures. To open the spherulitic microstructure, we added 30% w/w of an amorphous diluent (poly(ether-imide), PEI) serving as a marker. Small-angle X-ray scattering and dynamic mechanical analysis mere used to check on bulk samples that similar structural evolutions are obtained when reheating cold-crystallized PEEK and a 70/30 PEEK/PEI blend. We then monitored at T-c = 180 degrees C the isothermal growth of a single PEEK spherulite in a thin film of the PEEK/PEI blend and followed the growth and branching of individual PEEK fibrils, separated by channels of rejected PEI. Further, we examined the changes in semicrystalline morphology induced by subsequent reheating. The spatial locations of the fibrils (i.e., lamellar stacks) of this very spherulite were not modified up to an annealing temperature of about 300 degrees C. However, the surface of the fibrils became covered with numerous small protuberances (diameter: 50-200 nm) growing in size and in number as annealing temperature increased. We consider these images to be the first direct-space proof for the existence of a large-scale melting-recrystallization process occurring when reheating cold-crystallized PEEK.

Andromeda polifoliaL.

A low, glabrous, evergreen shrub, (5)-10-25-(40) cm tall. The flowering stems are decumbent to erect, sparingly branched, arising from a creeping, woody rhizome (Warming 1908; Fl. Eur. 3; Fl. Br. Isl.; Hegi Fl. 1, ed. 3; Ramneau et al. 1993; Stace 1997). The leaves are narrow, alternate, subsessile, coriaceous, oblong to linear, dark green above, silvery-glaucous beneath, 10-40 x 2-8 mm (Barvaux 1958; Fl. Eur. 3; Fl. Br. Isl.; Rameau et al. 1993; Stace 1997). They are mucronulate (Anderson 1961) or acute to apiculate (Fl. Eur. 3); their margins are usually revolute (Fl. Br. Isl.; Rameau et nl. 1993). The flowers are pentamerous (Barvaux 1958; Anderson 1961; Hegi Fl. 1, ed. 3), in very short, umbellike terminal racemes of 2-7-(12) (Warming 1908; Fl. Eur. 3; Rameau etal. 1993). However, Warming (1908) reported 4-merous flowers in Finnmark and in Greenland. The pedicels are pinkish, 2-4 times as long as the corolla (Barvaux 1958; Fl. Br. Isl.; Hegi Fl. 1, ed. 3); they are 7-15 mm long and slender (Fl. Eur. 3). The sepals are persistent, triangular, reddish, acute, about 1 .5 mm long (Anderson 1961; Fl. Eur. 3) and connate at base (Fl. Eur. 3). Two bracteoles lie at the extreme base of the pedicel, concealed by a bract (Fl. Eur. 3). Corolla globose-urceolate with 5 recurved teeth; drooping (Webb 1967), inclined or pendent (Fl. Eur. 3), bright pink at first, fading almost to white. It reaches 5-8 mm long (Warmzing 1908; Barvaux 1958; Anderson 1961; Fl. Br. Isl.; Hegi Fl. 1, ed. 3; Rameau et cal. 1993) and it continues to grow during flowering (Warming 1908). The interior of the corolla is covered with erect, usually somewhat upturned, hairs that extend to the margin of the limb (Warming 1908). The stigma lies just at or imnediately within the throat of the corolla, and the 10 anthers, which are at the level of the middle of the pistil and the corolla, bend inwards towards the style (Warming 1908; Barvaux 1958; Hegi Fl. 1, ed. 3; Rameau etal. 1993). The filaments are strongly swollen just above their slender short bases and are covered with fairly long hairs along the greater part of their length (Warming 1908; Anderson 1961). The anthers are covered with small protuberances; they open at the apex by two pores of irregular shape (Warming 1908; Hegi Fl. 1, ed. 3). The two apical appendages are as long as the anthers, glabrous and slightly curved (Warming 1908; And-

Dynamics of the hydrodynamical growth of columns on silicon exposed to ArF excimer-laser irradiation

We present new results about the development of the whiskerlike structures that grow on silicon single crystals exposed in air to ArF excimer-laser irradiation. Small depressions appear on the surface after 100-200 laser pulses. With the next pulses, the size of these depressions in- creases, without change in depth, and new depressions are formed. At the end of this step the non-depressed regions are constricted and form a reticular network with a mesh size of some mm. With more pulses the material of the net- work tends to desert the branches and accumulate in the nodes, and discrete hillocks result. The hillocks progres- sively change their shape until tall columns are formed. Independent of this process, small protuberances appear on flat areas of the irradiated spot, initially in regions far from the center of the spot. These protuberances evolve to mushroom-type shapes, which remain much shorter than the columns.

Modification of polysulfone gas separation membranes by additives

The incorporation of additives into polymers like bisphenol A polysulfone (PSF) can provide an attractive alternative for modifying their permselective properties for gas separation, provided the additive is appropriately selected. In this work, three series of additives based on naphthalene, bisphenol A, and fluorene structures were incorporated into PSF and their effect on gas transport properties was measured. The results show that these additives increase selectivity and reduce permeability of PSF when incorporated at low concentrations. The largest increases in selectivity for the gas pairs He/CH4, H2/CH4, and O2/N2 are caused by those additives that cause the largest reductions in the glass transition temperature and fractional free volume, and typically, they are made up of planar molecules containing polar or small asymmetric protuberances. The productivity—selectivity balance response of the modified PSF membranes reveals that the naphthalene-based additives containing asymmetric groups of atoms lead to membranes with higher selectivity and with only small losses in permeability relative to the unmodified PSF membranes. The addition of 20 wt % of the glassy additive Kenflex A into PSF causes a fourfold increase in the selectivity of PSF to He/CH4 at the expense of a 37% reduction in the permeability of helium. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 1925–1941, 1997

Adenovirus 3 penton dodecahedron exhibits structural changes of the base on fibre binding.

It was recently shown that co-expression of adenovirus type 3 (Ad3) penton base and fibre in the baculovirus system produces dodecahedral particles, as does the expression of the penton base alone. The structure of both of these dodecahedral particles, with and without fibre, has been determined by cryoelectron microscopy and 3-dimensional reconstruction techniques to a resolution of 25 and 20 A, respectively. The general form of the penton base resembles that of the base protein in the recent reconstruction of adenovirus type 2. There is a remarkable difference in the penton base structure with and without the fibre. The five small protuberances on the outer surface of each base move away from the 5-fold axis by approximately 15 A when the fibre is present. These protuberances are of relatively low density and most probably represent a flexible loop possibly containing the RGD site involved in integrin binding. The fibre is apparently bound to the outer surface of the penton base, rather than inserted into it. The fibre is flexible and the shaft contains two distinct globular regions 26 A in diameter. The volume of the inner cavity of the dodecahedron is 350 +/- 100 nm3. This small volume precludes the use of the inner cavity to house genetic information for gene therapy; however, the possibility remains of linking the gene to the dodecahedron surface in the hope that it will be internalized with the dodecahedron.

Scanning Electron Microscopy of Adult Wuchereria bancrofti (Nematoda: Filarioidea)

Despite the great importance of Wuchereria bancrofti in causing human lymphatic filariasis, only conventional morphological studies have been completed with adult forms of this filaria. No ultrastructural studies have been carried out, mainly due to the difficulty in obtaining viable parasites from human tissues and the lack of a suitable experimental model or in vitro cultivation. With the recent success in using ultrasound to localize adult worms in living tissues and their surgical recovery from human lymphatic vessels, we show in the present paper the first ultrastructural observations of this filarial form. The cuticle surface analyzed by scanning electron microscopy showed a transversal striated aspect with periodic annulations and many small protuberances irregularly distributed along the filaria. The adults present a specialized cephalic area, with the oral opening surrounded by a circular mouth, papillae, and amphidial opening. Other structures, for example the anal, vulvar, and cloacal opening and spicules, were also observed and are described herein.

REDESCRIPTION OF FEMALE AND MALE MESOCYCLOPS EDAX FORBES, 1891 (COPEPODA: CYCLOPOIDA)

ABSTRACT The female and male of Mesocyclops edax Forbes, 1891, are redescribed. This species comprises the following peculiarities compared to other representatives of Mesocyclops: a broad and deeply serrate hyaline membrane along the distal seventeenth antennular segment; the intercoxal plates of legs 1-3 with tiny spinules; leg 4 bearing 2 small protuberances; the inner seta of leg 4 endopod III nearly as long but smaller than the outer seta; a shovellike shape of the caudal setae; groups of hairs on the inner rim of the caudal rami; the shape of the genital field; and caryological and naupliar peculiarities. The present note provides the first description of the male. The male exhibits sexual dimorphism in size, the habitus, and the morphology of the antennule, antenna, leg 5, and leg 6. Morphological characters are compared and reevaluated with findings in the literature.

104 境界層内の突起が擬似衝撃波の構造に及ぼす影響

The effect of a small protuberance in a boundary layer on the structure of a λ-type pseudo-shock wave was experimentally investigated. The Mach number upstream of the pseudo-shock is 1.80. When the head of the pseudo-shock is located at the protuberance, the pseudo-shock is affected most and it consists of a series of oblique shock waves. In such a flow state, the wavy variation of the pressure distribution along the duct axis is much smaller in comparison with a pseudo-shock wave in the case of no protuberance.

On the taxonomy of the family Podolampadaceae Lindemann (Dinophyceae) with descriptions of three new genera

Dinoflagellate cells from the family Podolampadaceae from multiple locations in the world's oceans, were studied under the scanning electron microscope. The plate formula of the family is redefined based upon plate homology comparisons between the hypotheca of the closely related Peridinioid genus Diplopsalis Bergh and the hypotheca of different Podolampadacean genera. As in Diplopsalis, five postcingular plates and only one antapical plate are found in the hypotheca of the Podolampadaceans. The Podolampadacean plate formula may be written as: P o P t X 3′ la 5″ 3C 4–5S 4–5‴ 1″″, where P t refers to the cover plate in the apical pore complex (APC). Three new genera ( Mysticella, Gaarderia and Heterobractum) are proposed on the basis of the apical pore types, cell compression and/or cell bilateral asymmetry. A new combination for the former Blepharocysta striata Schütt is proposed as Mysticella striata (Schütt) Carbonell-Moore, comb. nov. Three types of APC were found in the Podolampadaceans: 1. Type 1: Pore plate with ridges and pores; cover plate with only a small protuberance; this apical pore is typical of Blepharocysta. 2. Type 2: Pores but no ridges on the pore plate; cover plate with a small spine. Lissodinium Matzenauer, emend. Carbonell-Moore and Mysticella Carbonell-Moore, gen. nov. illustrate this type of apical pore. 3. Type 3: Pore plate as in Type 2. Cover and canal plate with a continous pronounced ridge. Gaarderia Carbonell-Moore, gen. nov. and Heterobractum Carbonell-Moore, gen. nov. represent this kind of apical pore. A broad range in cell bilateral asymmetry and cell compression resulting in a pronounced cell distortion was evident in these dinoflagellates. In Blepharocysta there is almost no cell compression, while most species of Podolampas are dorso-ventrally compressed. Cells of Mysticella species may present no compression or may be slightly dorso-ventrally compressed. Lissodinium is laterally compressed and shows the highest degree of bilateral symmetry within the family. A unique bilateral plate asymmetry (and no cell compression) is observed in Heterobractum Carbonell-Moore, gen. nov. A pronounced cell distortion is found in the different species of Gaarderia Carbonell-Moore, gen. nov. Of all plate series, the cingular series show the most variation in both development (narrow to very wide) and relative plate size within the same series. Zygotic forms as evidence of a sexual life cycle were observed in some species. An evolutionary trend is briefly discussed.

A new blackfly species of Simulium (Gomphostilbia) from Solomon Islands, south pacific (diptera: simuliidae).

A new blackfly species, Simulium (Gomphostilbia) hiroshii sp. nov. is described based on female, male, pupal and larval specimens collected from the Solomon Islands, South Pacific. This species possesses several characters which are unusual for the subgenus Gomphostilbia as follows : in adults, basal part of the radius fully haired in the female but bare in the male, female frons almost bare and shiny, female tergites 5-8 shiny, male genitalia lacking parameral hooks; in the pupal stage, 4 respiratory filaments per side, sterna 6 and 7 devoid of outer hook on each side; larval hypostomium with serrate lateral margins, and larval body with a large conical protuberance dorsomedially on abdominal segment 7, as well as paired dorsolateral small protuberances on abdominal segments 1-4 and metathoracic segment. This is a first record of the subgenus Gomphostilbia from the Solomon Islands and represents the most easterly geographical distribution of the subgenus.

A first list of plant-parasitic nematodes from the Wilderness National Park, with a description of <i>Ogma sekgwaum</i> spec. nov.

Ogma sekgwaum spec. nov. is described and figured from the Wilderness National Park. Females of this species are characterized by having one lip annulus with smooth, wavy margin, no submedian lobes, 53-59 body annuli, not strongly retrorse anteriorly, but becoming more so posteriorly with 12-14 longitudinal rows of projections at midbody, gradually lengthening and attenuating towards posterior end of body, longer on post-vulval ventral side of body, not branched or bifurcate with small protuberances on extreme tips which become hair-like on post-vulval projections and a 64-81 (im long stylet. Ogma coronatum Schuurmans Stekhoven & Teunissen, 1938 is described and figured with notes on the juvenile. Additional measure^ ments and SEM photographs are given for Criconema duplicivestitum (Andrassy, 1963) Raski & Luc, 1985 and measurements for Ogma naomiae Van den Berg, 1992. A list is given of the other known plant-parasitic nematodes also found. Neolobocriconema palaniense Muthukrishnan, 1987 is transferred to Ogma palaniense (Muthukrishnan, 1987) comb. nov.

Effects of CPPU (N‐(2‐chloro‐4‐pyridyl)‐N'‐phenylurea) on fruit growth, maturity, and storage quality of kiwifruit

Abstract Effects of the synthetic cytokinin CPPU (N‐(2‐chloro‐4‐pyridyl)‐N'‐phenylurea; common name forchlorfenuron) on kiwifruit (Actinidia deliciosa) cv. Hayward fruit growth, maturity, and storage quality were examined. CPPU was applied to fruitlets 21 days after flowering, either as a 5 mg/ litre dip or as a 5 mg/litre spray. Dipping increased mean fresh weight of fruit at harvest by 43% and spraying by 33%. Most of the increase in fruit size was because of an increase in the volume of “small” isodiametric parenchyma cells in the outer pericarp. The volume of “large” ovoid parenchyma cells in the outer pericarp was not affected by CPPU treatment. CPPU application increased the rate of accumulation of soluble solids in fruit prior to harvest but did not increase the proportion of total dry matter. CPPU also caused increased growth of the outer pericarp at the stylar end of the fruit, resulting in small protuberances. Morphological attributes of fruit including the ratio of length to diameter, and flatn...

Three-dimensional analysis of the structure and composition of CA3 branched dendritic spines and their synaptic relationships with mossy fiber boutons in the rat hippocampus.

This paper is the third in a series to quantify differences in the composition of subcellular organelles and three-dimensional structure of dendritic spines that could contribute to their specific biological properties. Proximal apical dendritic spines of the CA3 pyramidal cells receiving synaptic input from mossy fiber (MF) boutons in the adult rat hippocampus were evaluated in three sets of serial electron micrographs. These CA3 spines are unusual in that they have from 1 to 16 branches emerging from a single dendritic origin. The branched spines usually contain subcellular organelles that are rarely found in adult spines of other brain regions including ribosomes, multivesicular bodies (MVB), mitochondria, and microtubules. MVBs occur most often in the spine heads that also contain smooth endoplasmic reticulum, and ribosomes occur most often in spines that have spinules, which are small nonsynaptic protuberances emerging from the spine head. Most of the branched spines are surrounded by a single MF bouton, which establishes synapses with multiple spine heads. The postsynaptic densities (PSDs) occupy about 10-15% of the spine head membrane, a value that is consistent with spines from other brain regions, with spines of different geometries, and with immature spines. Individual MF boutons usually synapse with several different branched spines, all of which originate from the same parent dendrite. Larger branched spines and MF boutons are more likely to synapse with multiple MF boutons and spines, respectively, than smaller spines and boutons. Complete three-dimensional reconstructions of representative spines with 1, 6, or 12 heads were measured to obtain the volumes, total surface areas, and PSD surface areas. Overall, these dimensions were larger for the complete branched spines than for unbranched or branched spines in other brain regions. However, individual branches were of comparable size to the large mushroom spines in hippocampal area CA1 and in the visual cortex, though the CA3 branches were more irregular in shape. The diameters of each spine branch were measured along the cytoplasmic path from the PSD to the origin with the dendrite, and the lengths of branch segments over which the diameters remained approximately uniform were computed for subsequent use in biophysical models. No constrictions in the segments of the branched spines were thin enough to reduce charge transfer along their lengths.(ABSTRACT TRUNCATED AT 400 WORDS)

Predator-Mediated Plasticity of Prey Life History and Morphology: Chaoborus americanus Predation on Daphnia pulex

Presence of the invertebrate predator Chaoborus americanus induces Daphnia pulex to assume an alternate, less vulnerable morphology, characterized by small protuberances (neck teeth) on the dorsal anterior margin of the head. Whereas previous studies on the demographic characteristics of this induced morphology in single genotypes indicated an unavoidable cost (delayed maturity), the results of this study indicate substantial genetic variance for induced life-history response. In addition, the degree of neck-tooth expression, while genetically variable, is a poor predictor of clone-specific life-history changes and fitness gain in the presence of Chaoborus predation. These results reveal several important characteristics of this system of inducible defense. First, the most notable trait of the morph (neck teeth) varies among genotypes. Therefore, the induced morph does not represent an on-off state. Second, the relative expression of neck teeth among clones is a poor predictor of induced life-history ch...

The Auditory System of an Atympanate Bushcricket Phasmodes Ranatriformes (Westwood) (Tettigoniidae: Orthoptera)

ABSTRACT The auditory system of the atympanate tettigoniid Phasmodes ranatriformes has been investigated using anatomical and physiological methods. The prothoracic tracheae show no specialization in terms of an acoustic spiracle, acoustic bullae or an enlargement of the trachea in the proximal tibia. Instead of a true tympanum, a depression with small cuticular protuberances is found on the proximal tibia of the foreleg. The complex tibial organ is formed from the three sensory organs usually found in tettigoniids. The crista acustica consists of about 16–18 receptor cells. Extracellular recordings from the leg nerve reveal sensitive responses to vibrational stimuli (at a threshold comparable to that found in other tettigoniids) only, and not to airborne sounds. The two possibilities either that this animal shows a secondary reduction of the auditory system or that it represents a primitive form are discussed. Developmental data from other tettigoniids seem to confirm the latter hypothesis.

Later events in suppression of Fusarium root rot of red pine seedlings by the ectomycorrhizal fungus Paxillus involutus

Colonization of primary roots of red pine (Pinus resinosa Ait.) seedlings by two isolates of the fungal pathogen Fusarium oxysporum Schlecht. emend Snyd. & Hans. f.sp. pini in a sterile, soil-free system and a nonsterile rooting medium was suppressed for 2 months if the roots were exposed to the ectomycorrhizal fungus Paxillus involutus (Batsch.) Fr. for 1 week before being inoculated with the pathogen. Roots of protected seedlings harboured only a few hyphae of the pathogen. These were either vacuolated or filled with slightly electron-dense substances and did not penetrate host cells. In contrast, roots of seedlings not inoculated by P. involutus were extensively colonized by F. oxysporum, and host tissue vacuolation and disorganization occurred. Papillae, consisting of either small protuberances or elongate projections, were infrequently formed in response to infection. Chlamydospores of F. oxysporum that formed in the sterile system had numerous lipid deposits and amorphous thick walls but few mitochondria and little endoplasmic reticulum. Key words: biological control, ectomycorrhiza, Fusarium, Pinus resinosa, disease suppression.

FLORAL INITIATION AND EARLY DEVELOPMENT IN ERIGERON PHILADELPHICUS (ASTERACEAE)

The order of floral initiation and subsequent organogeny of Erigeron philadelphicus L. (Asteraceae: Astereae) was found to deviate from the acropetal pattern generally reported for the Asteraceae. Light micrographs show periclinal divisions in the first, second, and deeper subsurface layers of cells on the flanks of the inflorescence apex as the earliest evidence of floral initiation. Scanning electron microscope micrographs indicate that the disk flowers appear first and arise as small protuberances approximately one‐third of the way up the previously and undifferentiated highly convex inflorescence apex. A succession of disk flowers arises acropetally in a complex anthotaxy characterized by about 21 dextrorse and 12–15 sinistrorse parastichies (although this pattern is obscured at the apex). After one to three disk flowers have been initiated in each parastichy, the first ray flower initials can be seen to initiate in sites proximal to the oldest and largest disk flowers. Additional ray flowers then initiate basipetally following the dextrorse parastichies established by the disk flowers. Overall floral initiation on the inflorescence apex proceeds acropetally for the disk flowers and basipetally for the ray flowers until the available space is filled. Floral development adheres to the same plan—proceeding bidirectionally on the inflorescence meristem with the oldest and most complete flowers of both types located on the equator established at initiation.

Floral Initiation and Early Development in Erigeron philadelphicus (Asteraceae)

The order of floral initiation and subsequent organogeny of Erigeron philadelphicus L. (Asteraceae: Astereae) was found to deviate from the acropetal pattern generally reported for the Asteraceae. Light micrographs show periclinal divisions in the first, second, and deeper subsurface layers of cells on the flanks of the inflorescence apex as the earliest evidence of floral initiation. Scanning electron microscope micrographs indicate that the disk flowers appear first and arise as small protuberances approximately one-third of the way up the previously and undifferentiated highly convex inflorescence apex. A succession of disk flowers arises acropetally in a complex anthotaxy characterized by about 21 dextrorse and 12–15 sinistrorse parastichies (although this pattern is obscured at the apex). After one to three disk flowers have been initiated in each parastichy, the first ray flower initials can be seen to initiate in sites proximal to the oldest and largest disk flowers. Additional ray flowers then initiate basipetally following the dextrorse parastichies established by the disk flowers. Overall floral initiation on the inflorescence apex proceeds acropetally for the disk flowers and basipetally for the ray flowers until the available space is filled. Floral development adheres to the same plan—proceeding bidirectionally on the inflorescence meristem with the oldest and most complete flowers of both types located on the equator established at initiation.

Surface Topography of Ion-Etched Si Wafers Studied by Electron Microscopy

Wafers of 111 and 100 Si which had been mirror-finished and then scratched by #1500–3000 grit abrasive paper were ion-etched and their surfaces were investigated by SEM and cross-sectional high-resolution TEM techniques. Ion etching was carried out at incident angles of 75°, 65°, 55° at 5 kV Ar+ ion beam by rotating the specimens around the axis normal to the wafer surface. The etched surface of the mirroe-finished Si wafer stayed smooth for 4 hours of ion etching. After more than 4 hours of ion etching, round projections of 1–10 µm in diameter were generated. Cross-sectional observation showed small pyramidal protuberances of 5–20 nm in height on the 100 surface with facets of (111). No protuberances were observed on the 111 surface. The thickness of the amorphous layer formed on the 111 surface was different from the one on the 100 surface.

Structure of the temporal organ of the Japanese house centipede, Thereuonema hilgendorfi Verhoeff.

The ultrastructure of the temporal organ of the Japanese house centipede, Thereuonema hilgendorfi Verhoeff (Chilopoda), has been examined. The temporal organ of this species is known to be a carbon dioxide receptor. It appears externally as a small protuberance with a small opening (5 μm) on its summit. There is a small cuticle-lined cavity beneath the protuberance, and a mushroom-shaped projection protrudes from the base of the cavity into its interior. Below the cavity is an encapsulated, bulb-shaped cellular mass (sensory bulb), which contains about ten receptor cells and 100 supporting cells. Nuclei of both receptor and supporting cells occur basally in the sensory bulb. Each receptor cell has a single dendrite, which gives rise to a pair of sensory cilia. The cilia enter the mushroom-shaped projection, and course along the inner surface of its calyx. The supporting cells have distal processes, which accompany the cilia into the calyx. The surface cuticle of the calyx consists of a fabric of fibrils, but in not layered like the cuticular integument. The fabric is permeable to water. The observed structure is discussed in relation to carbon dioxide reception and in comparison with the structure of olfactory receptors and hygroreceptors.