Outer Caps Research Articles

Progress towards an optically powered cryobot

AbstractVALKYRIE (Very-deep Autonomous Laser-powered Kilowatt-class Yo-yoing Robotic Ice Explorer) is a NASA-funded project to develop key technologies for an autonomous ice penetrator, or cryobot, capable of delivering science payloads through outer planet ice caps and terrestrial glaciers. This 4 year effort will produce a cylindrical cryobot prototype 280 cm in length and 25 cm in diameter. One novel element of VALKYRIE’s design is the use of a high-energy laser as the primary power source. 1070 nm laser light is transmitted at 5 kW from a surface-based laser and injected into a custom-designed optical waveguide that is spooled out from the descending cryobot. Light exits the downstream end of the fiber, travels through diverging optics, and strikes an anodized aluminum beam dump, which channels thermal power to hot-water jets that melt the descent hole. Some beam energy is converted to electricity via photovoltaic cells, for running on-board electronics and jet pumps. Since the vehicle can be sterilized prior to deployment, and forward contamination is minimized as the melt path refreezes behind the cryobot, expansions on VALKYRIE concepts may enable cleaner access to deep subglacial lakes. This paper focuses on laser delivery and beam dump thermal design.

Rhodachlya madagascarensis gen. et sp. nov.: a distinct acrochaetioid represents a new order and family (Rhodachlyales ord. nov., Rhodachlyaceae fam. nov.) of the Florideophyceae (Rhodophyta)

J.A. West, J.L. Scott, K.A. West, U. Karsten, S.L. Clayden and G.W. Saunders. 2008. Rhodachlya madagascarensis gen. et sp. nov.: a distinct acrochaetioid represents a new order and family (Rhodachlyales ord. nov., Rhodachlyaceae fam. nov.) of the Florideophyceae (Rhodophyta). Phycologia 47: 203–212. DOI: 10.2216/07-72.1A filamentous ‘acrochaetioid’ red algal epiphyte on Posidonia from Madagascar was isolated into culture. It reproduces solely by monosporangia and the spherical spores have gliding motility that differs from amoeboid spore motility seen with time-lapse video microscopy in most Acrochaetiales and Colaconematales. Electron microscopy reveals that a peripheral encircling thylakoid is absent in the chloroplast, Golgi bodies are associated with mitochondria, and pit plugs have platelike outer and inner caps and lack a cap membrane. Low-molecular-weight carbohydrates are floridoside and trehalose. Molecular evidence (small subunit, large subunit and EF2 sequences) resolved this taxon as a completely novel lineage of the Nemaliophycidae, and it is here described as Rhodachlya madagascarensis J.A. West et al., gen. et sp. nov. In light of the unusual combination of ultrastructural features and the lack of affinity to any of the currently recognized families and orders in molecular analyses, this alga forms the basis of a new family, Rhodachlyaceae G.W. Saunders et al., fam. nov., and order, Rhodachlyales G.W. Saunders et al., ord. nov., of the subclass Nemaliophycidae.

TH-C-T-617-06: Error Analysis in Monte Carlo Simulation of Low Energy Brachytherapy Sources

Purpose: The AAPM recommends two independent investigators to determine the dosimetric characteristics of any new brachytherapy sources before their clinical applications. In this recommendation, it is suggested that one of the two investigators must include Monte Carlo simulation technique. The accuracy of Monte Carlo simulation technique is highly dependent on accuracy of the source geometry and material information that is provided by the manufacturers, and the approximations taken during the simulations. In the present work, the effects of various parameters like configuration of active pellets, outer wall thickness and end cap thickness on the accuracy of the dosimetric characteristics of the brachytherapy sources have been investigated. Also, studies were performed to determine the effect of embedded radioactive elements within the source, and effect of number of histories used for calculating the dosimetric parameters. Method and Materials: Monte Carlo simulation code PTRAN version 7.43 was used to simulate the source designs in water medium. The photon cross section used for these simulations was DLC-146, distributed by the Radiation Sciences Information Computing Center at Oak Ridge National Laboratory. The variations of dosimetric characteristics of different brachytherapy source design with a fixed radionuclide were obtained following the AAPM TG-43U1 recommendations. Results: The results of these investigations showed that the anisotropy function and anisotropy factors of the source were considerably affected by the thickness of the outer wall and end caps. Whereas, the radial dose function and the dose rate constant were not significantly affected by these parameters. Moreover larger histories are required to obtain dosimetric characteristics at larger distances with acceptable (< ± 2%) statistical uncertainty range. Conclusion: This study suggests that the Monte Carlo simulated 2D anisotropy functions for low energy brachytherapy sources are very sensitive to the geometric parameters of the source and number of histories used in simulation.

Distribution of ergosterol in different tissues of mushrooms and its effect on the conversion of ergosterol to vitamin D 2 by UV irradiation

Analysis of ergosterol content in different tissues of Shiitake mushrooms showed a significant difference ( p < 0.01) in its distribution. Thus, the conversion of ergosterol in whole mushrooms to vitamin D 2, by exposure to UV irradiation, was significantly affected ( p < 0.01) by the orientation of the mushroom tissues to the UV. The highest ergosterol content was found in button mushrooms (7.80 ± 0.35 mg/g DM) while the lowest was in enoki mushrooms (0.68 ± 0.14 mg/g DM). The conversion of ergosterol to vitamin D 2 was about four times higher when gills were exposed to UV-A irradiation than when the outer caps were exposed to the same. The lowest conversion to vitamin D 2 (12.5 ± 0.28 μg/g DM) was observed for button mushrooms while the highest value (45.1 ± 3.07 μg/g DM) was observed for oyster mushrooms. The optimum moisture content of mushrooms for this conversion was around 78% on a wet basis and the temperature was around 35 °C.

Phylogenesis of pit-plug-associated features in the Rhodophyta: inferences from molecular systematic data

Small-subunit ribosomal RNA sequence data are presented for Rhodogorgon carriebowensis Norris et Bucher (Rhodogorgonales, Rhodophyta) and Galaxaura marginata (Ellis et Solander) Lamouroux (Nemaliales, Rhodophyta). Data for these species were included in a matrix consisting of small-subunit ribosomal RNA sequences for 70 taxonomically diverse red algal species. Distance, parsimony, and maximum-likelihood analyses of these data all strongly support (100% of bootstrap replicates for distance and parsimony) a close alliance between the Rhodogorgonales and Corallinales. Our alignment includes 19 species representing six florideophyte orders (Acrochaetiales, Batrachospermales, Corallinales, Nemaliales, Palmariales, Rhodogorgonales) in which pit plugs are characterized by two cap layers. Distance and parsimony analyses resolve a monophyletic lineage including all "two-cap-layer" species. Our parsimony-derived molecular phylogeny was used to test a published hypothesis of pit-plug evolution. Four aspects of Pueschel's hypothesis are consistent with the results of our molecular systematic study: (i) "naked" plugs represent the ancestral type, (ii) outer cap layers are homologous structures, (iii) domed outer caps are ancestral to plate-like outer caps, and (iv) cap membranes are a derived feature within the two-cap-layer lineage. Directions for future research are discussed. Key words: Acrochaetiales, Batrachospermales, Corallinales, molecular systematics, Nemaliales, Palmariales, phylogeny, pit plug, Rhodogorgonales, Rhodophyta.

Unusual morphological and cytochemical features of pit plugs inClathromorphum circumscriptum(Rhodophyta, Corallinales)

Ultrastructural and cytochemical study of pit plugs in Clathromorphum circumscriptum revealed two distinctive features. The large outer cap layer of the pit plugs was irregular in morphology and often deeply lobed. Some plug caps were poorly consolidated, consisting of disjunct pieces that were not in contact with the rest of the pit plug. As in other Corallinales, the outer cap layer was reactive to periodic acid Schiff, a carbohydrate stain, and mercuric bromophenol blue, a protein stain; it was also sensitive to digestion by two proteolytic enzymes. In addition, a lipid stain, Sudan black B, stained the outer caps. This was the first demonstration, in any species, of pit plug outer caps with a significant lipid component. Morphological and cytochemical features of pit plugs could be of value in elucidating relationships among some species of Clathromorphum.

Cytochemical evidence for homology of the outer cap layer of red algal pit plugs

Abstract A comparative cytochemical study of the outer cap layer of pit plugs in five orders of red algae (Rhodophyta) was performed in order to address the question of homology of this systematically important feature. Two or more representatives of the Acrochaetiales, Nemaliales, Palmariales, Batrachospermales, and Corallinales were examined. Outer caps large enough to be resolved by light microscopy were found to be reactive to the periodic acid Schiff procedure, specific for carbohydrates, and to a protein stain, mercuric bromophenol blue, but not to Sudan black B, a lipid stain. Using transmission electron microscopy, it was found that the proteolytic enzyme, proteinase K, removed much of the material constituting the outer cap. These results, together with similarities of phosphotungstic-chromic acid staining, suggest that the outer cap layer of pit plugs in all five orders is composed of glycoproteins. These findings provide evidence, but not definitive proof, that the outer caps of red algal pit p...

Immunohistochemical and biochemical evidence for the putative inhibitory neurotransmitters histamine and GABA in lobster olfactory lobes

As an initial effort to investigate possible inhibitory interactions in the olfactory system of the spiny lobster, studies were conducted to identify and localize the putative inhibitory neurotransmitters histamine and GABA in the olfactory lobe. Biochemical studies demonstrated that olfactory lobe tissue was capable of synthesizing histamine from radioactive histidine and GABA from glutamic acid. Immunohistochemistry was used to localize histamine and GABA in brain sections, by using either avidin-biotin conjugated peroxidase or fluorescein conjugated secondary antibody. Specific histamine-like and GABA-like immunoreactivity was found in soma clusters of olfactory interneurons, adjacent to the olfactory lobe. Small, putative glial cells displaying intense histamine-like immunoreactivity were found interspersed among the glomeruli of the lobe. The accessory lobe exhibited moderate immunostaining for both histamine and GABA. Positive immunostaining for histamine and GABA was also found in the olfactory lobes, with a predominance of staining in the outer caps of the glomeruli, which are thought to be the regions where the primary afferent terminals contact the processes of second-order olfactory neurons. These findings collectively implicate inhibition at the first synaptic level of the olfactory pathway in the spiny lobster.

Cytological and taxonomic studies of the Euglenales. I. Ultrastructure and envelope elemental composition inTrachelomonas

The ultrastructural cytology, envelope microarchitecture and elemental composition are described for species from three of Pringsheim's subgeneric categories of the euglenoid flagellate, Trachelomonas. Except for differences in chloroplast number and pyrenoid morphology, cellular organization in T. bulla, T. zorensis and T. lefevrei is similar; however, based on our finding that T. lefevrei has inner and outer paramylon caps over the pyrenoid, we propose that this species be moved from its present position in the subgroup with inner pyrenoids, to the subgroup with double-sheathed pyrenoids. Envelope microarchitecture, elemental composition and colour are correlated in each of the species. Elemental analyses indicate that envelopes or regions of envelopes with high iron content have a granular substructure, whereas those rich in manganese have a needle-like microcrystalline substructure. Envelopes of T. bulla never appear dark in the light microscope (L.M.) and have a granular microarchitecture with iron a...

局部義歯の維持装置に関する一考察

Based on clinical experience over ten years, provision of ridge support for fabrication of removable partial denture was considered to be important for support and stability of the dentures.About 1960, Dr. K.H. Körber improved some disadvantages of the old telescope system and developed so-called Konuskronen telescope. Many clinical results have been reported, since the theoretical background and prognosis of the new device were introduced to Japan.It is without doubt a superb device, however, avthor has experienced some difficulty in it, as follows:1) In the case where anterior teeth are the abutments, those are replaced by full-veneered gold crowns. when the partial denture is removed, anterior gold crowns show. This may cause an esthetic problem, which delicately affects to the patient's psychology.2) Retention of Konuskrone is derived from the forces of friction between inner and outer caps. In this mechanism, very slight space is required between the occlusal surface of an inner cap and the inside of an outer cap. The existence of this space, however, causen such problems as follows:(a) Substance of an outer cap of an abutment tooth at the time when it functions, may loose centric stops.(b) When veneered with resin on the outer cap and if shoulder is made at the cervical part of an inner cap, the retention may be lost due to contact of this part.It is considered, as a counterplan, that the shoulder part of an outer cap should be cut away slightly or an inner cap to be tapered. The former has a demerit in plaue intrusion, while the latter in contour of an outer cap.(c) The support depending merely upon the effect of friction, author feels, show some difficulties in revelation of such grasping force as per an operator intends, and in adjusting at the time supporting force decreases after years later.In order to overcome these disadvantages, author has conceived a new supporting device combining those advantages of the abovementioned device with I.C. attachment. Author has obtained, thereupon, good results in clinical application. Since the device has been newly conceived, author will need time to observe and pursue the prognosis after years.

Ultrastructure of septal pore apparatus in the lamellae of Nematoloma puiggarii

The lamellae of Nematoloma puiggarii have dolipore–parenthesome septa like the majority of the basidiomycetes. The septal pore canal is almost always transected by a central electron-dense zone. Often two more electron-dense zones, one on each side of the central one, are present in the canal. Pore canal openings are normally occluded by granular electron-dense plugs which are ring like in subbasidial and subhymenial septa and appear solid in some tramal septa. A hemispherical fibrous outer cap is always present outside the parenthesomes of subhymenial septa. Tramal septa do not have outer caps, and the subbasidial septa have them only on the subhymenial sides. The outer caps are usually delimited externally by either the cisternae of endoplasmic reticulum or by the tonoplast of adjacent vacuoles.

The fine structure of septal pore apparatus in the lamellae of Pholiota terrestris

The lamellae of Pholiota terrestris, when viewed in thin sections cut perpendicular to the hymenial surface, consist of a hymenial layer of basidia and scattered cystidia, an interwoven subhymenium, and a trama. The inner trama is composed of a zone of relatively large, vacuolated hyphal elements, whereas the outer trama consists of smaller hyphal elements with relatively dense cytoplasmic contents. The septal pore apparatus throughout the lamellae are similar to those described in most other Homobasidiomycetes and saprobic Heterobasidiomycetes. In the center of the septal pore there is a narrow electron-dense zone that intersects the pore canal. In some septal pores similar electron-dense zones occur near one or both orifices. The septal cap consists of three membranes, of which the two defining membranes appear clearly tripartite in cross section. The pores in the septal cap are arranged hexagonally and are 70–105 nm in diameter. The proximal septal caps of the subbasidial septa and those in the subhymenium develop an electron-dense, granular outer cap that is usually delimited externally by endoplasmic reticulum or, less often, by the tonoplast of an adjacent vacuole. The septal pores of the subbasidial septa become plugged by the expanded septal swelling following basidiospore discharge. The septal pore apparatus in the trama are not associated with outer caps; however, many septal pores in the trama become occluded with electron-dense plugs near both orifices. The observations of the septal pore apparatus in the lamellae of P. terrestris are compared with studies of other Homobasidiomycetes and saprobic Heterobasidiomycetes.

The fine structure of the centriolar apparatus and associated structures in the complex flagellates Trichonympha and Pseudotrichonympha

The centriolar apparatus in the flagellate genera Trichonympha and Pseudotrichonympha is located at the anterior end of the cell, in the rostrum. It forms part of a complex system of structures which includes the rostral tube, inner and outer caps, and the rostral flagella. The fine structure of these organelles is described in detail on the basis of an electron-microscope study of sectioned and negatively stained material. In Trichonympha the rostral tube is a hollow cylinder, made of a cross-striated protein with a periodicity of about 450 Å. This is organized into radially arranged lamellae, which continue posteriorly as the parabasal filaments. The tube is continuous anteriorly with two finely striated crescentic bodies, which correspond to the so-called short centrioles of some previous workers. There is no evidence that they are centriolar in function. In the interphase cell the centriolar apparatus consists principally of a long centriolar rod, of complex fine structure, lying in the anterior end of the rostral tube. There is no evidence of typical centriolar structure in this, but at division an aster forms around one end of it. Surmounting the apex of the rostral tube is a dense, finely fibrous body, the inner cap. Lying within this there is a typical centriole (similar in structure to a basal body), and also the basal body of one flagellum, which appears to be distinct from all the rest. The functions of these two structures are not known. The margin of the inner cap connects with the complex system of delicate fibres which links the basal bodies of the rostral flagella. The function of the fibres, and possibly also of the inner cap, may be to coordinate the activities of the rostral flagella. The outer cap is composed mainly of tubules, 250 Å in diameter, but shows variations in structure in different species. The structures in Pseudotrichonympha which presumably serve similar functions are in many respects very differently organized. The rostral tube is more complex, with distinct inner and outer walls of different fine structure. There are also complex inner and outer surface layers. A striking feature is that although the various components of the tube are quite different in structure, they display a common periodicity in their organization. The centriolar apparatus appears to consist principally of two dense bands running along the inner wall of the tube, connecting anteriorly to an extended layer of centriolar material to which spindle fibres are attached in radially polarized fashion throughout interphase. There is no centriolar rod or typical centriole, such as is found in Trichonympha . Very elaborate systems of fibres are associated with the inner cap and the anterior end of the rostral tube. The two genera are compared, and the findings related to knowledge of centriolar structures in other types of cell. Possible evolutionary explanations for the complexity and variation in fine structure in these flagellates are considered.