Sample records for psenud filmi nitamise

  1. Desiccation tolerance of Hymenophyllacea filmy ferns is mediated by constitutive and non-inducible cellular mechanisms.


    Garcés Cea, Marcelo; Claverol, Stephan; Alvear Castillo, Carla; Rabert Pinilla, Claudia; Bravo Ramírez, León


    The Hymenophyllaceae is a primitive family within the Filicopsidae. One of the most exceptional features of this family of ferns is the presence of fronds with one or just a few cell layers (hence their name of filmy ferns), and the absence of stomata. Hymenophyllum caudiculatum and Hymenophyllum dentatum are able to lose more than 82% of their fully hydrated water content, to remain dry for extended periods of time (days or weeks), and to survive and remain viable following rehydration. The aim of this work was to understand whether the adaptive strategy of the Hymenophyllaceae for desiccation tolerance is constitutive or inducible. A proteomic approach was adopted in combination with physiological parameters to assess whether there were changes in the protein content during dehydration and following rehydration. Detached fronds were used to monitor the rates of photosynthesis in desiccation experiments, sugar accumulation, and high-resolution 2-DE to analyze proteome variation during a desiccation-rehydration cycle. The analyzed proteome exhibited little variation (3-4%) between hydrated and desiccated states, while variation was greater between the desiccated and rehydrated states (8.7-10%). Eighty-two discrete proteins were analyzed by MS/MS, and 65 were identified. About 21% of the analyzed proteins (17) were mixtures of two or more different polypeptides. Of the identified proteins, more than a half (33 spots, 55%) had functions related to energy-photosynthesis. The second largest category with known function (five spots, 8%) was related to cell rescue, defense, and virulence. More than one in every four proteins analyzed belonged to a group of hypothetical proteins (18 spots, 28%). The results suggest that the Hymenophyllaceae represent an example of a change in adaptive strategy from a typical vascular to the poikilohydric homoiochlorophyllous adaptation, which they share with the bryophytes that grow in profusion in the same habitats. The speed at which

  2. Light and desiccation responses of some Hymenophyllaceae (filmy ferns) from Trinidad, Venezuela and New Zealand: poikilohydry in a light-limited but low evaporation ecological niche

    PubMed Central

    Proctor, Michael C. F.


    Background and Aims Hymenophyllaceae (filmy ferns) are typically plants of shady, constantly moist habitats. They attain greatest species diversity and biomass in humid tropical montane forests and temperate hyperoceanic climates. This paper presents ecophysiological data bearing on their worldwide ecological niche space and its limits. Methods Chlorophyll fluorescence was used to monitor recovery in desiccation experiments, and for measurements of 95 % saturating irradiance [photosynthetic photon flux density (PPFD95 %)] of photosynthetic electron flow and other parameters, in the New Zealand Hymenophyllum sanguinolentum, and three species each of Hymenophyllum and Trichomanes from forests in Trinidad and Venezuela. Key Results Hymenophyllum sanguinolentum was comparable in desiccation tolerance and light responses with the European species. The more common species in the two tropical forests showed PPFD95 % >100 µmol m−2 s−1, and withstood moderate desiccation (–40 MPa) for several days. The four most shade-adapted species had PPFD95 % ≤51 µmol m−2 s−1, and were sensitive to even mild and brief desiccation (–22 MPa for 3 d). Conclusions Light and desiccation responses of filmy ferns can be seen as an integrated package. At low light and windspeed in humid forests, net radiation and saturation deficit are low, and diffusion resistance high. Water loss is slow and can be supported by modest conduction from the sub-stratum. With higher irradiance, selection pressure for desiccation tolerance increases progressively. With low light and high humidity, the filmy fern pattern of adaptation is probably optimal, and the vascular plant leaf with mesophyll and stomata offers no advantage in light capture, water economy or CO2 uptake. Trade-offs between light adaptation and desiccation tolerance, and between stem conduction and water absorption through the leaf surface, underlie adaptive radiation and niche differentiation of species within the family

  3. Comparative Ecophysiological Measurements on the Light Responses, Water Relations and Desiccation Tolerance of the Filmy Ferns Hymenophyllum wilsonii Hook. and H. tunbrigense (L.) Smith

    PubMed Central



    Chlorophyll‐fluorescence and infrared gas analyser measurements show saturation of photosynthetic electron flow and CO2 uptake at generally lower irradiances in Hymenophyllum tunbrigense than in H. wilsonii, but with wide variation in both species (63–189 µmol m–2 s–1 PPFD in H. tunbrigense, 129–552 µmol m–2 s–1 PPFD in H. wilsonii), probably related to both site and season. Non‐photochemical quenching (at 400 µmol m–2 s–1 PPFD) ranged from 2·1 to 8·1, with no significant difference between the species. Pressure–volume curves from thermocouple‐psychrometer measurements give full‐turgor osmotic potentials of approx. –1·4 MPa in both species, and indicate low apoplast fractions and high cell‐wall elastic moduli. Leaves of H. tunbrigense recovered within 24 h from up to 7 d desiccation at water potentials ranging from –40 MPa (74 % relative humidity, RH) to –220 MPa (20 % RH); after 15 or 30 d, desiccation recovery was slower and less complete, and leaves were severely damaged at the highest and lowest humidities. Hymenophyllum wilsonii recovered well from up to 30 d desiccation at –114 and –220 MPa, but at –40 MPa it showed signs of damage after 15 d, and was severely damaged or killed after 30 d. Results are discussed in relation to the ecological and geographical distributions of the two species, and to the adaptive strategies of filmy ferns in general. PMID:12714369

  4. From Empire to "Filmi:" A Fusion of Western and Indian Cultural Practices in Australian Music Education

    ERIC Educational Resources Information Center

    Southcott, Jane; Joseph, Dawn


    During the 19th and 20th centuries, Indian culture was represented in Australia as part of celebrations of the British Empire. Children were presented with stereotypic representations of Indian culture, which provide a snapshot of contemporary perceptions. Such representations were rarely authentic. By removing music from one culture and…

  5. Electrochemistry of surfactant-doped polypyrrole film(I): Formation of columnar structure by electropolymerization

    SciTech Connect

    Naoi, Katsuhiko; Oura, Yasushi; Maeda, Michiko; Nakamura, Sadako


    Electroactive polypyrrole (PPy) films have been studied widely in the field of applied material science for high energy/power storage applications. Perpendicularly oriented columnar structure was obtained for electropolymerized polypyrrole films formed from micellar solution of anionic surfactants. The surfactants used as dopants were a class of anionic surfactant, namely, Na salts of dodecyl sulfate (SDS) and dodecylbenzene sulfonate (SDBS). The formation process of polypyrrole films on electrode surfaces was studied with in situ atomic force microscopy (AFM) and electrochemical quartz crystal microbalance (EQCM) methods to monitor the structure of the grown polymers. In EQCM measurement, the frequency shift ({Delta}f) and the resonance resistance ({Delta}R) of the quartz crystal electrode were obtained simultaneously. An abrupt increase in {Delta}R was observed for both PPy/DS and PPy/DBS films at about 60--100mC/cm{sup 2}. Such a drastic change in {Delta}R, which may be associated with the emergence of the viscoelastic properties of the films, could be explained by the formation of columnar structure. In situ AFM observation clearly indicated that such a structure started to form around these critical charges. The cyclic voltammograms for the PPy/DS and PPy/DBS{sup {minus}} films showed sharp redox couples observed around {minus}0.5 to 0.6 V. The diffusion rate of cations for the resulting films was studied with ac impedance measurement as a function of the concentration of surfactant dopants. As the PPy film was prepared in higher concentration of the surfactant dopant, where the micelles are formed in solution, the resulting film showed a considerably higher (ca. 3 orders of magnitude) diffusion coefficient compared to ordinary PPy films so far reported. Such an enhanced diffusivity of ions could be attributed to a special formation process of polypyrrole in micelle solution: the mechanism is discussed here.

  6. Quenched carbonaceous composite - Fluorescence spectrum compared to the extended red emission observed in reflection nebulae

    NASA Technical Reports Server (NTRS)

    Sakata, Akira; Wada, Setsuko; Narisawa, Takatoshi; Asano, Yoichi; Iijima, Yutaka; Onaka, Takashi; Tokunaga, Alan T.


    The photoluminescence (fluorescence) of a film of the laboratory-synthesized quenched carbonaceous composite (filmy QCC) is shown to have a single broad emission feature with a peak wavelength that varies from 670 to 725 nm, and coincides with that of the extended red emission observed in reflection nebulae. The rapid decay of the filmy QCC red fluorescence in air and of the stable blue fluorescence of the filmy QCC dissolved in liquid Freon suggests that the red fluorescence originates from the interaction of active chemical species and aromatic components in the filmy QCC. A material similar in nature to that of the filmy QCC may be a major component of interstellar dust.

  7. Cataract


    ... seeing may include: Being sensitive to glare Cloudy, fuzzy, foggy, or filmy vision Difficulty seeing at night ... often determine this in advance. Possible Complications Early diagnosis and treatment are key to preventing permanent vision ...

  8. Ultraviolet spectra of quenched carbonaceous composite derivatives: Comparison to the '217 nanometer' interstellar absorption feature

    NASA Technical Reports Server (NTRS)

    Sakata, Akira; Wada, Setsuko; Tokunaga, Alan T.; Narisawa, Takatoshi; Nakagawa, Hidehiro; Ono, Hiroshi


    QCCs (quenched carbonaceous composite) are amorphus carbonaceous material formed from a hydrocarbon plasma. We present the UV-visible spectra of 'filmy QCC; (obtained outside of the beam ejected from the hydrocarbon plasma) and 'dark QCC' (obtained very near to the beam) for comparison to the stellar extinction curve. When filmy QCC is heated to 500-700 C (thermally altered), the wavelength of the absorption maximum increases form 204 nm to 220-222 nm. The dark QCC has an absorption maximum at 217-222 nm. In addition, the thermally altered filmy QCC has a slope change at about 500 nm which resmbles that in the interstellar extinction curve. The resemblance of the extinction curve of the QCCs to that of the interstellar medium suggests that QCC derivatives may be representative of the type of interstellar material that produces the 217 nm interstellar medium feature. The peak extinction of the dark QCC is higher than the average interstellar extinction curve while that of the thermally altered filmy QCC is lower, so that a mixture of dark and thermally altered filmy QCC can match the peak extinction observed in the interstellar medium. It is shown from electron micrographs that most of the thermally altered flimy QCC is in the form of small grainy structure less than 4 nm in diameter. This shows that the structure unit causing the 217-222 nm feature in QCC is very small.

  9. Mesh insertion as an aid for pleurodesis.


    Sugarmann, W M; Widmann, W D; Mysh, D; Sattari, R


    With the application of video-assisted thoracic surgery (VATS) for the treatment of pneumothorax, there has been an increase in the failure rate of treatment because of inadequate pleurodesis. We sought to determine whether mesh insertion into the pleural cavity with or without pleural abrasion results in predictable pleurodesis appropriate for clinical trial as an adjunct to VATS treatment of pneumothorax. There have been no prior studies on the use of absorbable or nonabsorbable mesh in the thoracic cavity. The effects of intra-thoracic absorbable polyglactin (Vicryl) and non-absorbable polypropylene (Marlex) mesh were studied in rats. Polyglactin without abrasion caused filmy adhesions in 5/5, 1/7, and 0/5 rats studied at 1, 2, and 3 months. Polypropylene incites an extensive and dense pleural reaction not suitable for clinical use becaues it induces a fibrothorax. Pleural abrasion alone caused variable adhesions studied at 3-4 months (4/6 none, 1/6 filmy, 1/6 firm). Polyglactin plus pleural abrasion resulted in appropriate firm adhesions in 7/8 rats studied at 3-4 months with 1/8 showing filmy adhesions. Polyglactin alone results in transient filmy adhesions. Pleural abrasion alone results in inadequate pleural symphysis. However, when absorbable mesh insertion is coupled with pleural abrasion, appropriate pleurodesis is predictably achieved. Clinical application of polyglactin mesh insertion with pleural abrasion as an adjunct in the VATS treatment of pneumothorax has begun and has been successful. PMID:10064371

  10. Bilinguals' Creativity and Syntactic Theory: Evidence for Emerging Grammar.

    ERIC Educational Resources Information Center

    Bhatia, Tej K.


    Examines a code mixed variety of English and Hindi called Filmi English, which reflects the linguistic influence of the Indian film industry. A corpus of more than 2,000 intrasentential code-mixed sentences drawn from a film magazine, "Stardust," is analyzed. (Author/OD)

  11. Femtosecond pulse generation from a topological insulator mode-locked fiber laser.


    Liu, Hao; Zheng, Xu-Wu; Liu, Meng; Zhao, Nian; Luo, Ai-Ping; Luo, Zhi-Chao; Xu, Wen-Cheng; Zhang, Han; Zhao, Chu-Jun; Wen, Shuang-Chun


    We reported on the generation of femtosecond pulse in a fiber ring laser by using a polyvinyl alcohol (PVA)-based topological insulator (TI), Bi2Se3 saturable absorber (SA). The PVA-TI composite has a low saturable optical intensity of 12 MW/cm2 and a modulation depth of ~3.9%. By incorporating the fabricated PVA-TISA into a fiber laser, mode-locking operation could be achieved at a low pump threshold of 25 mW. After an optimization of the cavity parameters, optical pulse with ~660 fs centered at 1557.5 nm wavelength had been generated. The experimental results demonstrate that the PVA could be an excellent host material for fabricating high-performance TISA, and also indicate that the filmy PVA-TISA is indeed a good candidate for ultrafast saturable absorption device. PMID:24664035

  12. Muscular, myocutaneous, and fasciocutaneous flaps in complex urethral reconstruction.


    Zinman, Leonard


    The ability to achieve a long-term, stable, stricture-free, hairless urethral lumen in patients with complex anterior stricture and compromised genital skin is one of the ongoing challenges of reconstructive urologic surgery. The conservative approach by endoscopic urethrotomy or dilatation with a self-catheterization schedule rarely affects a definitive cure except in the short filmy superficial strictures of the bulbous portion of the urethra. Genital fasciocutaneous island flaps are currently the golden standard for definitive, reliable resolution of anterior urethral strictures in patients who have not undergone a prior surgical procedure that may alter the penile or scrotal circulation, or those with skin loss from trauma, decubiti, radiation, or balanitis xerotica obliterans. PMID:12371235

  13. Influence of different morphology of three-dimensional Cu(x)O with mixed facets modified air-cathodes on microbial fuel cell.


    Liu, Ziqi; Li, Kexun; Zhang, Xi; Ge, Baochao; Pu, Liangtao


    Three kinds of three-dimensional (3D) CuxO catalysts were prepared to modify activated carbon air-cathode using a facile electrochemical method with addition of surfactants. The maximum power density of MFC using SC-Cu air cathode (added sodium citrate into the electrolyte solution in electrodeposition process) was 1550±47 mW m(-2), almost 77% higher than AC cathode. Specifically, the charge transfer resistance significantly decreased by 89% from 9.3980 Ω to 1.0640 Ω compared to the control. Lumphy and mutually embedded filmy sheet structure were observed in SEM, which provided sufficient active sites for oxygen adsorption and diffusion. In XRD and TEM result, CuxO with mixed facets showed special structure which had a better performance. Crystallization condition of electrodeposited materials played a significant role in their nature electrochemical properties, morphology controlled by surfactant of CuxO exhibited high properties on the air-cathode MFC. PMID:26122090

  14. Quenched carbonaceous composite. III - Comparison to the 3.29 micron interstellar emission feature

    NASA Technical Reports Server (NTRS)

    Sakata, A.; Wada, S.; Onaka, T.; Tokunaga, A. T.


    Laboratory data are presented showing that oxidized f-QCC, after heating to 500 C, has a 3.29 micron absorption feature that matches precisely the wavelength of the 3.29 micron interstellar emission feature. In addition, the width of the f-QCC (filmy quenched carbonaceous composite) feature is close to that of the 3.29 micron emission feature observed in NGC 7027, Orion, and IRAS 21282 + 5050. Laboratory spectra of polycyclic aromatic hydrocarbons (PAHs) were also obtained, and comparison of the f-QCC and PAH absorption spectra to that of the 3.29 micron emission feature indicates that the f-QCC provides a much better match. It is thus suggested that f-QCC is representative of the class of material giving rise to the emission features in the interstellar medium.

  15. Nanometer-Scale Epitaxial Strain Release in Perovskite Heterostructures Using 'SrAlOx' Sliding Buffer Layers

    SciTech Connect

    Bell, Christopher


    We demonstrate the strain release of LaAlO{sub 3} epitaxial film on SrTiO{sub 3} (001) by inserting ultra-thin 'SrAlO{sub x}' buffer layers. Although SrAlO{sub x} is not a perovskite, nor stable as a single phase in bulk, epitaxy stabilizes the perovskite structure up to a thickness of 2 unit cells (uc). At a critical thickness of 3 uc of SrAlO{sub x}, the interlayer acts as a sliding buffer layer, and abruptly relieves the lattice mismatch between the LaAlO{sub 3} filmand the SrTiO{sub 3} substrate, while maintaining crystallinity. This technique may provide a general approach for strain relaxation of perovskite film far below the thermodynamic critical thickness. A central issue in heteroepitaxial filmgrowth is the inevitable difference in lattice constants between the filmand substrate. Due to this lattice mismatch, thin film are subjected to microstructural strain, which can have a significan effect on the filmproperties. This challenge is especially prominent in the rapidly developing fiel of oxide electronics, where much interest is focused on incorporating the emergent physical properties of oxides in devices. Although strain can be used to great effect to engineer unusual ground states, it is often deleterious for bulk first-orde phase transitions, which are suppressed by the strain and symmetry constraints of the substrate. While there are some reports discussing the control of the lattice mismatch in oxides using thick buffer layers, the materials choice, lattice-tunable range, and control of misfit dislocations are still limited. In this Letter, we report the fabrication of strain-relaxed LaAlO{sub 3} (LAO) thin film on SrTiO{sub 3} (STO) (001) using very thin 'SrAlO{sub x}' (SAO) buffer layers. Whereas for 1 or 2 pseudo-perovskite unit cells (uc) of SAO, the subsequent LAO filmis strained to the substrate, at a critical thickness of 3 uc the SAO interlayer abruptly relieves the lattice mismatch between the LAO and the STO, although maintaining the

  16. Epiphytes as an Indicator of Climate Change in Hawaii

    NASA Astrophysics Data System (ADS)

    Kettwich, S. K.


    Although climate change threatens many ecosystems, current research in this field suggests tropical vegetation lags in response. Epiphytes, or arboreal vegetation, occupy tight, climate-defined niches compared with co-occurring life forms such as trees, yet there have been few studies of Hawaii's epiphyte communities. Because of Hawaii Island's natural climatic diversity, it is an ideal location to understand how these intrinsically climate sensitive plants interact with the atmosphere and evaluate how they may serve as a near-term indicator of climate change. Here we establish a baseline from which changes in corticolous epiphyte communities can be monitored as a leading indicator of likely forest changes by 1) investigating patterns of epiphyte abundance and species composition across elevation and precipitation gradients on windward Hawaii Island, and 2) using physiological measurements to investigate the relative importance of rain vs. fog in epiphyte-atmosphere interactions. The precipitation gradient keeps elevation constant at 1000m, while varying precipitation between 2,400 and 6,400 mm/year. The elevation gradient keeps rainfall constant at 3000mm/year, and varies elevation between 200 and 1750 m. Forest sites are dominated by Ohia Lehua (Metrosideros polymorpha) across broad geographic and climatological ranges thus allowing examination of epiphytes on this single host. We quantified bryophytes and vascular plants growing on Ohia trunks with standardized diameter and branching characteristics. Overall, epiphyte communities showed much finer scale responses to climate variation when compared with structurally dominant vegetation (which was broadly similar at all sites). The precipitation gradient exhibits a clear increase in abundance of all epiphyte groups and a definable increase in diversity with increasing rainfall. Results across the elevation gradient show a higher abundance of filmy ferns and bryophytes above the lifting condensation level (about

  17. Widely-tunable, passively Q-switched erbium-doped fiber laser with few-layer MoS2 saturable absorber.


    Huang, Yizhong; Luo, Zhengqian; Li, Yingyue; Zhong, Min; Xu, Bin; Che, Kaijun; Xu, Huiying; Cai, Zhiping; Peng, Jian; Weng, Jian


    We propose and demonstrate a MoS2-based passively Q-switched Er-doped fiber laser with a wide tuning range of 1519.6-1567.7 nm. The few-layer MoS2 nano-platelets are prepared by the liquid-phase exfoliation method, and are then made into polymer-composite film to construct the fiber-compatible MoS2 saturable absorber (SA). It is measured at 1560 nm wavelength, that such MoS2 SA has the modulation depth of ∼ 2% and the saturable optical intensity of ∼ 10 MW/cm(2). By further inserting the filmy MoS2-SA into an Er-doped fiber laser, stable Q-switching operation with a 48.1 nm continuous tuning from S- to C-waveband is successfully achieved. The shortest pulse duration and the maximum pulse energy are 3.3 μs and 160 nJ, respectively. The repetition rate and the pulse duration under different operation conditions have been also characterized. To the best of our knowledge, it is the first demonstration of MoS2 Q-switched, widely-tunable fiber laser. PMID:25401559

  18. An Australian webspinner species makes the finest known insect silk fibers

    SciTech Connect

    Okada, Shoko; Weisman, Sarah; Trueman, Holly E.; Mudie, Stephen T.; Haritos, Victoria S.; Sutherland, Tara D.


    Aposthonia gurneyi, an Australian webspinner species, is a primitive insect that constructs and lives in a silken tunnel which screens it from the attentions of predators. The insect spins silk threads from many tiny spines on its forelegs to weave a filmy sheet. We found that the webspinner silk fibers have a mean diameter of only 65 nm, an order of magnitude smaller than any previously reported insect silk. The purpose of such fine silk may be to reduce the metabolic cost of building the extensive tunnels. At the molecular level, the A. gurneyi silk has a predominantly beta-sheet protein structure. The most abundant clone in a cDNA library produced from the webspinner silk glands encoded a protein with extensive glycine-serine repeat regions. The GSGSGS repeat motif of the A. gurneyi silk protein is similar to the well-known GAGAGS repeat motif found in the heavy fibroin of silkworm silk, which also has beta-sheet structure. As the webspinner silk gene is unrelated to the silk gene of the phylogenetically distant silkworm, this is a striking example of convergent evolution.

  19. Effect of Intercritical Annealing on Microstructural Evolution and Properties of Quenched & Partitioned (Q&P) Steels

    NASA Astrophysics Data System (ADS)

    Wu, Riming; Jin, Xuejun; Wang, Chenglin; Wang, Li


    Transformation of metastable austenite into martensite in novel quenched & partitioned (Q&P) steels improves sheet formability, allowing this class of high-strength steels to be used for automotive structural components. The current work studies the microstructural evolution by varying intercritical annealing time ( t a), as well as its influence on the martensite-austenite constituent and mechanical properties of Q&P steels. As the t a was prolonged, the morphology of retained austenite progressively transformed from block to a mixture of block and film, and finally changed to totally film. Based on electron back-scatter diffraction (EBSD) measurements and uniaxial tensile response, the holding time of 600 s at 760 °C was determined to produce the best results in terms of highest volume fraction of retained austenite ( f γ = 15.8%) and largest strain (26.8%) at the ultimate tensile strength (892 MPa). This difference in work-hardening behavior corresponds directly to the transformation rate of retained austenite with different morphology. The slower rate of transformation of filmy austenite allowed for work hardening to persist at high strains where the transformation effect had already been exhausted in the blocky one. There is great potential for properties improvement through adjustment of metastability of retained austenite.

  20. Cotransport of viruses and clay particles in water saturated and unsaturated porous media

    NASA Astrophysics Data System (ADS)

    Chrysikopoulos, C. V.; Syngouna, V. I.


    This experimental study examines the effects of clay colloids on the transport of viruses in variably saturated porous media. All cotransport experiments were conducted in both saturated and partially saturated columns packed with glass beads, using bacteriophages MS2 and ΦΧ174 as model viruses, and kaolinite (KGa-1b) and montmorillonite (STx-1b) as model clay colloids. The various experimental collision efficiencies were determined using the classical colloid filtration theory. The experimental data indicated that the mass recovery of viruses and clay colloids decreased as the water saturation decreased. Temporal moments of the various breakthrough concentrations collected, suggested that the presence of clays significantly influenced virus transport and irreversible deposition onto glass beads. The mass recovery of both viruses, based on total effluent virus concentrations, was shown to reduce in the presence of suspended clay particles. Furthermore, the transport of suspended virus and clay-virus particles was retarded, compared to the conservative tracer. Under unsaturated conditions both clay particles hindered the transport of the two viruses considered in this work. Moreover, the surface properties of viruses, clays and glass beads were employed for the construction of classical DLVO and capillary potential energy profiles, and the results suggested that capillary forces play a significant role on colloid retention. It was estimated that the capillary potential energy of MS2 is lower than that of ΦΧ174, and the capillary potential energy ofKGa-1b is lower than that of STx-1b, assuming that the protrusion distance through the water filmis the same for each pair of particles. Moreover, the capillary potential energy is several orders of magnitude greater than the DLVO energy potential. Figure 1Schematic illustration of the various concentrations involved in the cotransport experiments for: (a) saturated and (b) unsaturated porous media.

  1. Evolution of the rpoB-psbZ region in fern plastid genomes: notable structural rearrangements and highly variable intergenic spacers

    PubMed Central


    Background The rpoB-psbZ (BZ) region of some fern plastid genomes (plastomes) has been noted to go through considerable genomic changes. Unraveling its evolutionary dynamics across all fern lineages will lead to clarify the fundamental process shaping fern plastome structure and organization. Results A total of 24 fern BZ sequences were investigated with taxon sampling covering all the extant fern orders. We found that: (i) a tree fern Plagiogyria japonica contained a novel gene order that can be generated from either the ancestral Angiopteris type or the derived Adiantum type via a single inversion; (ii) the trnY-trnE intergenic spacer (IGS) of the filmy fern Vandenboschia radicans was expanded 3-fold due to the tandem 27-bp repeats which showed strong sequence similarity with the anticodon domain of trnY; (iii) the trnY-trnE IGSs of two horsetail ferns Equisetum ramosissimum and E. arvense underwent an unprecedented 5-kb long expansion, more than a quarter of which was consisted of a single type of direct repeats also relevant to the trnY anticodon domain; and (iv) ycf66 has independently lost at least four times in ferns. Conclusions Our results provided fresh insights into the evolutionary process of fern BZ regions. The intermediate BZ gene order was not detected, supporting that the Adiantum type was generated by two inversions occurring in pairs. The occurrence of Vandenboschia 27-bp repeats represents the first evidence of partial tRNA gene duplication in fern plastomes. Repeats potentially forming a stem-loop structure play major roles in the expansion of the trnY-trnE IGS. PMID:21486489

  2. Removal of Radioactive Nuclides by Multi-Functional Microcapsules Enclosing Inorganic Ion-Exchangers and Organic Extractants

    SciTech Connect

    Mimura, H.; Akiba, K.; Onodera, Y.


    The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The fine powders of inorganic ion-exchanger and oil drops of extractant were kneaded with sodium alginate (NaALG) solution and the kneaded sol readily gelled in a salt solution of CaCl2, BaCl2 or HCl to form spherical gel particles. The uptake properties of various nuclides, 137Cs, 85Sr, 60Co, 88Y, 152Eu and 241Am, for thirty-four specimens of microcapsules in the presence of 10-1-10-4 M HNO3 were evaluated by the batch method. The distribution coefficient (Kd) of Cs+ above 103 cm3/g was obtained for the microcapsules enclosing CuFC or AMP. The Kd of Sr2+ around 102 cm3/g was obtained for the microcapsules containing clinoptilolite, antimonic acid, zeolite A, zeolite X or titanic acid. The microcapsules enclosing DEHPA exhibited relatively large Kd values of trivalent metal ions above 103 cm3/g; for example, the Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were 1.1x104, 7.5x10, 1.1x10, 1.0x104, 1.4x104, 3.4x103 cm3/g, respectively. The uptake rates of Cs+, Y3+, Eu3+ and Am3+ for this microcapsule were rather fast; the uptake percentage above 90% was obtained after 19 h-shaking and the uptake equilibrium was attained within 1 d. The AMP/CaALG exhibited high uptake ability for Cs+ even after irradiation of 188 kGy, and DEHPA/CaALG microcapsule had similar Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ ions before and after irradiation. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into gelling salt solution. The microcapsules enclosing inorganic ion-exchangers and extractants have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions.

  3. Epiphyte Water Retention and Evaporation in Native and Invaded Tropical Montane Cloud Forests in Hawaii

    NASA Astrophysics Data System (ADS)

    Mudd, R. G.; Giambelluca, T. W.


    Epiphyte water retention was quantified at two montane cloud forest sites in Hawai'i Volcanoes National Park, one native and the other invaded by an alien tree species. Water storage elements measured included all epiphytic mosses, leafy liverworts, and filmy ferns. Tree surface area was estimated and a careful survey was taken to account for all epiphytes in the sample area of the forest. Samples were collected and analyzed in the lab for epiphyte water retention capacity (WRC). Based on the volume of the different kinds of epiphytes and their corresponding WRC, forest stand water retention capacity for each survey area was estimated. Evaporation from the epiphyte mass was quantified using artificial reference samples attached to trees that were weighed at intervals to determine changes in stored water on days without significant rain or fog. In addition, a soil moisture sensor was wrapped in an epiphyte sample and left in the forest for a 6-day period. Epiphyte biomass at the Native Site and Invaded Site were estimated to be 2.89 t ha-1 and 1.05 t ha-1, respectively. Average WRC at the Native Site and Invaded Site were estimated at 1.45 mm and 0.68 mm, respectively. The difference is likely due to the presence of the invasive Psidium cattleianum at the Invaded Site because its smooth stem surface is unable to support a significant epiphytic layer. The evaporation rate from the epiphyte mass near WSC for the forest stand at the Native Site was measured at 0.38 mm day-1, which represented 10.6 % of the total ET from the forest canopy at the Native Site during the period. The above research has been recently complemented by a thorough investigation of the WSC of all water storage elements (tree stems, tree leaves, shrubs, grasses, litter, fallen branches, and epiphytes) at six forested sites at different elevations within, above, and below the zone of frequent cloud-cover. The goal of this study was to create an inexpensive and efficient methodology for acquiring

  4. Musing over Microbes in Microgravity: Microbial Physiology Flight Experiment

    NASA Technical Reports Server (NTRS)

    Schweickart, Randolph; McGinnis, Michael; Bloomberg, Jacob; Lee, Angie (Technical Monitor)


    New York City, the most populated city in the United States, is home to over 8 million humans. This means over 26,000 people per square mile! Imagine, though, what the view would be if you peeked into the world of microscopic organisms. Scientists estimate that a gram of soil may contain up to 1 billion of these microbes, which is as much as the entire human population of China! Scientists also know that the world of microbes is incredibly diverse-possibly 10,000 different species in one gram of soil - more than all the different types of mammals in the world. Microbes fill every niche in the world - from 20 miles below the Earth's surface to 20 miles above, and at temperatures from less than -20 C to hotter than water's boiling point. These organisms are ubiquitous because they can adapt quickly to changing environments, an effective strategy for survival. Although we may not realize it, microbes impact every aspect of our lives. Bacteria and fungi help us break down the food in our bodies, and they help clean the air and water around us. They can also cause the dark, filmy buildup on the shower curtain as well as, more seriously, illness and disease. Since humans and microbes share space on Earth, we can benefit tremendously from a better understanding of the workings and physiology of the microbes. This insight can help prevent any harmful effects on humans, on Earth and in space, as well as reap the benefits they provide. Space flight is a unique environment to study how microbes adapt to changing environmental conditions. To advance ground-based research in the field of microbiology, this STS-107 experiment will investigate how microgravity affects bacteria and fungi. Of particular interest are the growth rates and how they respond to certain antimicrobial substances that will be tested; the same tests will be conducted on Earth at the same times. Comparing the results obtained in flight to those on Earth, we will be able to examine how microgravity induces

  5. Understanding and improving the mechanical stability of semiconducting polymers for flexible and stretchable electronics

    NASA Astrophysics Data System (ADS)

    Printz, Adam David

    -aggregate model---a spectroscopic model which estimates the quantity and quality of aggregates in a polymer film---is used to determine how the microstructure of a semiconducting polymer thin film evolves with repetitive strain. Samples strained below the yield point undergo little microstructural evolution, while samples strained above the yield point exhibit a significant decrease in aggregation and tensile modulus. Appendix C describes the invention of an environmentally-friendly fabrication technique, abrasion lithography.