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Sample records for dry biological fibrillar

  1. A design methodology for biologically inspired dry fibrillar adhesives

    NASA Astrophysics Data System (ADS)

    Aksak, Burak

    Realization of the unique aspects of gecko adhesion and incorporating these aspects into a comprehensive design methodology is essential to enable fabrication of application oriented gecko-inspired dry fibrillar adhesives. To address the need for such a design methodology, we propose a fibrillar adhesion model that evaluates the effect of fiber dimensions and material on adhesive performance of fiber arrays. A fibrillar adhesion model is developed to predict the adhesive characteristics of an array of fibrillar structures, and quantify the effect of fiber length, radius, spacing, and material. Photolithography techniques were utilized to fabricate elastomer microfiber arrays. Fibers that are fabricated from stiff SU-8 photoresist are used to fabricate a flexible negative mold that facilitates fabrication of fiber arrays from various elastomers with high yield. The tips of the cylindrical fibers are modified to mushroom-like tip shapes. Adhesive strengths in excess of 100 kPa is obtained with mushroom tipped elastomer microfibers. Vertically aligned carbon nanofibers (VACNFs) are utilized as enhanced friction materials by partially embedding inside soft polyurethanes. Friction coefficients up to 1 were repeatedly obtained from the resulting VACNF composite structures. A novel fabrication method is used to attach Poly(n-butyl acrylate) (PBA) molecular brush-like structures on the surface of polydimethylsiloxane (PDMS). These brushes are grown on unstructured PDMS and PDMS fibers with mushroom tips. Pull-off force is enhanced by up to 7 times with PBA brush grafted micro-fiber arrays over unstructured PDMS substrate. Adhesion model, initially developed for curved smooth surfaces, is extended to self-affine fractal surfaces to better reflect the adhesion performance of fiber arrays on natural surfaces. Developed adhesion model for fiber arrays is used in an optimization scheme which estimates optimal design parameters to obtain maximum adhesive strength on a given

  2. Fibrillar Organic Phases And Their Roles In Rigid Biological Composites

    SciTech Connect

    Arey, Bruce W.; Park, John J.; Mayer, George

    2015-06-01

    This study focused on determining the presence of organic phases in the siliceous components of rigid marine composites ("glass" sponge spicules), and thereby to clarify how those composites dissipate significant mechanical energy. Through the use of imaging by helium ion microscopy in the examination of the spicules, the organic phase that is present between the layers of hydrated silica was also detected within the silica cylinders of the composite, indicating the existence therein of a network, scaffolding, or other pattern that has not yet been determined. It was concluded that the presence of an interpenetrating network of some kind, and tenacious fibrillar interfaces are responsible for the large energy dissipation in these siliceous composites by viscoelastic processes. This discovery means that future mechanics analyses of such composites, extending to large deformations must consider such interpenetrating phases.

  3. Adhesion and sliding response of a biologically inspired fibrillar surface: experimental observations.

    PubMed

    Yao, H; Rocca, G Della; Guduru, P R; Gao, H

    2008-07-01

    Inspired by the adhesion mechanisms of several animal species such as geckos, beetles and flies, several efforts in designing and fabricating surface engineering strategies have been made recently to mimic the adhesive and frictional behaviour of biological foot pads. An important feature of such biological adhesion systems is the ability to switch between strong attachment and easy detachment, which is crucial for animal locomotion. Recent investigations have suggested that such a 'switching' mechanism can be achieved by the elastic anisotropy of the attachment pad, which renders the magnitude of the detachment force to be direction dependent. This suggestion is supported by the observations that the fibres of the foot pads in geckos and insects are oriented at an angle to the base and that geckos curl their toes backwards (digital hyperextension) while detaching from a surface. One of the promising bio-inspired architectures developed recently is a film-terminated fibrillar PDMS surface; this structure was demonstrated to result in superior detachment force and energy dissipation compared with a bulk PDMS surface. In this investigation, the film-terminated fibrillar architecture is modified by tilting the fibres to make the surface vertically more compliant and elastically anisotropic. The directional detachment and the sliding resistance between the tilted fibrillar surfaces and a spherical glass lens are measured: both show significant directional anisotropy. It is argued that the anisotropy introduced by the tilted fibres and the deformation-induced change in the compliance of the fibre layer are responsible for the observed anisotropy in the detachment force.

  4. Adhesion and sliding response of a biologically inspired fibrillar surface: experimental observations.

    PubMed

    Yao, H; Rocca, G Della; Guduru, P R; Gao, H

    2008-07-01

    Inspired by the adhesion mechanisms of several animal species such as geckos, beetles and flies, several efforts in designing and fabricating surface engineering strategies have been made recently to mimic the adhesive and frictional behaviour of biological foot pads. An important feature of such biological adhesion systems is the ability to switch between strong attachment and easy detachment, which is crucial for animal locomotion. Recent investigations have suggested that such a 'switching' mechanism can be achieved by the elastic anisotropy of the attachment pad, which renders the magnitude of the detachment force to be direction dependent. This suggestion is supported by the observations that the fibres of the foot pads in geckos and insects are oriented at an angle to the base and that geckos curl their toes backwards (digital hyperextension) while detaching from a surface. One of the promising bio-inspired architectures developed recently is a film-terminated fibrillar PDMS surface; this structure was demonstrated to result in superior detachment force and energy dissipation compared with a bulk PDMS surface. In this investigation, the film-terminated fibrillar architecture is modified by tilting the fibres to make the surface vertically more compliant and elastically anisotropic. The directional detachment and the sliding resistance between the tilted fibrillar surfaces and a spherical glass lens are measured: both show significant directional anisotropy. It is argued that the anisotropy introduced by the tilted fibres and the deformation-induced change in the compliance of the fibre layer are responsible for the observed anisotropy in the detachment force. PMID:17971321

  5. Dry self-cleaning properties of hard and soft fibrillar structures.

    PubMed

    Gillies, Andrew G; Puthoff, Jonathan; Cohen, Michael J; Autumn, Kellar; Fearing, Ronald S

    2013-07-10

    Recently, gecko-inspired synthetic adhesives (GSAs) have been made using a variety of fabrication techniques and materials, with one made from a hard polymer having been reported to recover its shear adhesion after fouling by normal use, or "dry self-clean", a feature useful for applications in wall crawling robots, reusable adhesives, microfabrication and solar panel cleaning. This paper investigates the impact of two design parameters on the dry self-cleaning capability of GSAs by experimentally testing two GSAs after fouling with small (1 μm), medium (3-10 μm), and large (40-50 μm) particles. We found that a GSA made from a hard thermoplastic with nanoscopic fibers was able to recover 96-115% of its shear adhesion after fouling with small and large but not medium particles, while a GSA made from a soft polymer and microscopic fibers recovered 40-55% on medium and large particles, with SEM imaging revealing particles embedding within the polymer. An analysis of the contact strength between fibers, particles and substrates of various dimensions and elasticity reveals that dry self-cleaning will be more effective for GSAs fabricated with smaller fiber diameters and for GSAs fabricated from materials with smaller loss functions, such as hard thermoplastics. These results have important implications on the choice of materials and geometries used for GSAs when dry self-cleaning capability is a desired function in the material. PMID:23786527

  6. Dry self-cleaning properties of hard and soft fibrillar structures.

    PubMed

    Gillies, Andrew G; Puthoff, Jonathan; Cohen, Michael J; Autumn, Kellar; Fearing, Ronald S

    2013-07-10

    Recently, gecko-inspired synthetic adhesives (GSAs) have been made using a variety of fabrication techniques and materials, with one made from a hard polymer having been reported to recover its shear adhesion after fouling by normal use, or "dry self-clean", a feature useful for applications in wall crawling robots, reusable adhesives, microfabrication and solar panel cleaning. This paper investigates the impact of two design parameters on the dry self-cleaning capability of GSAs by experimentally testing two GSAs after fouling with small (1 μm), medium (3-10 μm), and large (40-50 μm) particles. We found that a GSA made from a hard thermoplastic with nanoscopic fibers was able to recover 96-115% of its shear adhesion after fouling with small and large but not medium particles, while a GSA made from a soft polymer and microscopic fibers recovered 40-55% on medium and large particles, with SEM imaging revealing particles embedding within the polymer. An analysis of the contact strength between fibers, particles and substrates of various dimensions and elasticity reveals that dry self-cleaning will be more effective for GSAs fabricated with smaller fiber diameters and for GSAs fabricated from materials with smaller loss functions, such as hard thermoplastics. These results have important implications on the choice of materials and geometries used for GSAs when dry self-cleaning capability is a desired function in the material.

  7. Uncovering three-dimensional gradients in fibrillar orientation in an impact-resistant biological armour

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Paris, O.; Terrill, N. J.; Gupta, H. S.

    2016-05-01

    The complex hierarchical structure in biological and synthetic fibrous nanocomposites entails considerable difficulties in the interpretation of the crystallographic texture from diffraction data. Here, we present a novel reconstruction method to obtain the 3D distribution of fibres in such systems. An analytical expression is derived for the diffraction intensity from fibres, explaining the azimuthal intensity distribution in terms of the angles of the three dimensional fibre orientation distributions. The telson of stomatopod (mantis shrimp) serves as an example of natural biological armour whose high impact resistance property is believed to arise from the hierarchical organization of alpha chitin nanofibrils into fibres and twisted plywood (Bouligand) structures at the sub-micron and micron scale. Synchrotron microfocus scanning X-ray diffraction data on stomatopod telson were used as a test case to map the 3D fibre orientation across the entire tissue section. The method is applicable to a range of biological and biomimetic structures with graded 3D fibre texture at the sub-micron and micron length scales.

  8. Uncovering three-dimensional gradients in fibrillar orientation in an impact-resistant biological armour.

    PubMed

    Zhang, Y; Paris, O; Terrill, N J; Gupta, H S

    2016-01-01

    The complex hierarchical structure in biological and synthetic fibrous nanocomposites entails considerable difficulties in the interpretation of the crystallographic texture from diffraction data. Here, we present a novel reconstruction method to obtain the 3D distribution of fibres in such systems. An analytical expression is derived for the diffraction intensity from fibres, explaining the azimuthal intensity distribution in terms of the angles of the three dimensional fibre orientation distributions. The telson of stomatopod (mantis shrimp) serves as an example of natural biological armour whose high impact resistance property is believed to arise from the hierarchical organization of alpha chitin nanofibrils into fibres and twisted plywood (Bouligand) structures at the sub-micron and micron scale. Synchrotron microfocus scanning X-ray diffraction data on stomatopod telson were used as a test case to map the 3D fibre orientation across the entire tissue section. The method is applicable to a range of biological and biomimetic structures with graded 3D fibre texture at the sub-micron and micron length scales. PMID:27211574

  9. Uncovering three-dimensional gradients in fibrillar orientation in an impact-resistant biological armour

    PubMed Central

    Zhang, Y.; Paris, O.; Terrill, N. J.; Gupta, H. S.

    2016-01-01

    The complex hierarchical structure in biological and synthetic fibrous nanocomposites entails considerable difficulties in the interpretation of the crystallographic texture from diffraction data. Here, we present a novel reconstruction method to obtain the 3D distribution of fibres in such systems. An analytical expression is derived for the diffraction intensity from fibres, explaining the azimuthal intensity distribution in terms of the angles of the three dimensional fibre orientation distributions. The telson of stomatopod (mantis shrimp) serves as an example of natural biological armour whose high impact resistance property is believed to arise from the hierarchical organization of alpha chitin nanofibrils into fibres and twisted plywood (Bouligand) structures at the sub-micron and micron scale. Synchrotron microfocus scanning X-ray diffraction data on stomatopod telson were used as a test case to map the 3D fibre orientation across the entire tissue section. The method is applicable to a range of biological and biomimetic structures with graded 3D fibre texture at the sub-micron and micron length scales. PMID:27211574

  10. Carbon nanotubes: Fibrillar pharmacology

    NASA Astrophysics Data System (ADS)

    Kostarelos, Kostas

    2010-10-01

    The mechanisms by which chemically functionalized carbon nanotubes flow in blood and are excreted through the kidneys illustrate the unconventional behaviour of these fibrillar nanostructures, and the opportunities they offer as components for the design of advanced delivery vehicles.

  11. The fibrillar collagen family.

    PubMed

    Exposito, Jean-Yves; Valcourt, Ulrich; Cluzel, Caroline; Lethias, Claire

    2010-01-01

    Collagens, or more precisely collagen-based extracellular matrices, are often considered as a metazoan hallmark. Among the collagens, fibrillar collagens are present from sponges to humans, and are involved in the formation of the well-known striated fibrils. In this review we discuss the different steps in the evolution of this protein family, from the formation of an ancestral fibrillar collagen gene to the formation of different clades. Genomic data from the choanoflagellate (sister group of Metazoa) Monosiga brevicollis, and from diploblast animals, have suggested that the formation of an ancestral alpha chain occurred before the metazoan radiation. Phylogenetic studies have suggested an early emergence of the three clades that were first described in mammals. Hence the duplication events leading to the formation of the A, B and C clades occurred before the eumetazoan radiation. Another important event has been the two rounds of "whole genome duplication" leading to the amplification of fibrillar collagen gene numbers, and the importance of this diversification in developmental processes. We will also discuss some other aspects of fibrillar collagen evolution such as the development of the molecular mechanisms involved in the formation of procollagen molecules and of striated fibrils. PMID:20386646

  12. Characterization of a non-fibrillar-related collagen in the mollusc Haliotis tuberculata and its biological activity on human dermal fibroblasts.

    PubMed

    Fleury, Christophe; Serpentini, Antoine; Kypriotou, Magdalini; Renard, Emmanuelle; Galéra, Philippe; Lebel, Jean-Marc

    2011-10-01

    In invertebrates, members of the collagen family have been found in various phyla. Surprisingly, in mollusc, little is known about such molecules. In this study, we characterize the full-length abalone type IV collagen and we analysed its biological effects on human fibroblast in order to gain insights about this molecule in molluscs and particularly clues about its roles. We screened a cDNA library of Haliotis tuberculata hemocytes. The expression pattern of the transcript is determined using real-time polymerase chain reaction and in situ hybridization. The close identity between α1(IV) C-terminal domain and the vertebrate homologue led us to produce, purify and test in vitro a recombinant protein corresponding to this region using human dermal fibroblasts cell culture. The biological effects were evaluated on proliferation and on differentiation. We found that the 5,334-bp open reading frame transcript encodes a protein of 1,777 amino acids, including an interrupted 1,502-residue collagenous domain and a 232-residue C-terminal non-collagenous domain. The expression pattern of this transcript is mainly found in the mantle and hemocytes. The recombinant protein corresponding α1(IV) C-terminal domain increased fibroblast proliferation by 69% and doubled collagen synthesis produced in primary cultures. This work provides the first complete primary structure of a mollusc non-fibrillar collagen chain and the biological effects of its C-terminal domain on human cells. In this study, we prove that the NC1 domain from a molluscan collagen can improve human fibroblast proliferation as well as differentiation.

  13. Improved Adhesion and Compliancy of Hierarchical Fibrillar Adhesives.

    PubMed

    Li, Yasong; Gates, Byron D; Menon, Carlo

    2015-08-01

    The gecko relies on van der Waals forces to cling onto surfaces with a variety of topography and composition. The hierarchical fibrillar structures on their climbing feet, ranging from mesoscale to nanoscale, are hypothesized to be key elements for the animal to conquer both smooth and rough surfaces. An epoxy-based artificial hierarchical fibrillar adhesive was prepared to study the influence of the hierarchical structures on the properties of a dry adhesive. The presented experiments highlight the advantages of a hierarchical structure despite a reduction of overall density and aspect ratio of nanofibrils. In contrast to an adhesive containing only nanometer-size fibrils, the hierarchical fibrillar adhesives exhibited a higher adhesion force and better compliancy when tested on an identical substrate.

  14. Rational design and nanofabrication of gecko-inspired fibrillar adhesives.

    PubMed

    Hu, Shihao; Xia, Zhenhai

    2012-08-20

    Gecko feet integrate many intriguing functions such as strong adhesion, easy detachment, and self-cleaning. Mimicking gecko toe pad structure leads to the development of new types of fibrillar adhesives useful for various applications. In this Concept article, in addition to the design of adhesive mimics by replicating gecko geometric features, we show a new trend of rational design by adding other physical, chemical, and biological principles on to the geometric merits, for enhancing robustness, responsive control, and durability. Current challenges and future directions are highlighted in the design and nanofabrication of biomimetic fibrillar adhesives.

  15. Probing the biology of dry biological systems to address the basis of seed longevity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drying cells reduces molecular mobility and slows chemical and physical reactions. As a result, dry biological systems deteriorate slowly. The time course of deterioration in a population of living cells often follows a sigmoidal pattern in which aging is occurring but no changes to viability are ...

  16. Fibrillar Adhesive for Climbing Robots

    NASA Technical Reports Server (NTRS)

    Pamess, Aaron; White, Victor E.

    2013-01-01

    A climbing robot needs to use its adhesive patches over and over again as it scales a slope. Replacing the adhesive at each step is generally impractical. If the adhesive or attachment mechanism cannot be used repeatedly, then the robot must carry an extra load of this adhesive to apply a fresh layer with each move. Common failure modes include tearing, contamination by dirt, plastic deformation of fibers, and damage from loading/ unloading. A gecko-like fibrillar adhesive has been developed that has been shown useful for climbing robots, and may later prove useful for grasping, anchoring, and medical applications. The material consists of a hierarchical fibrillar structure that currently contains two levels, but may be extended to three or four levels in continuing work. The contacting level has tens of thousands of microscopic fibers made from a rubberlike material that bend over and create intimate contact with a surface to achieve maximum van der Waals forces. By maximizing the real area of contact that these fibers make and minimizing the bending energy necessary to achieve that contact, the net amount of adhesion has been improved dramatically.

  17. Adhesion enhancement in a biomimetic fibrillar interface.

    PubMed

    Glassmaker, Nicholas J; Jagota, Anand; Hui, Chung-Yuen

    2005-07-01

    Two important putative functions of the fibrillar contact interfaces commonly found in lizards and insects are to provide contact compliance and enhanced adhesion. To explore the question of whether a fibrillar architecture inherently enhances adhesion, we constructed model structures consisting of thin sheets of poly(vinyl butyral) (PVB) bonded on one of their thin sides to glass plates. The PVB samples had two flat, unstructured regions interrupted by a central fibrillar region along the bonded interface. The effect of the fibrillar geometry on the performance of the adhesive bond was tested using a tensile pull-off test, in which failure occurred by interfacial crack propagation, starting at an end where a crack initiator was introduced. We observed that fibrils in all samples fail consistently at the same critical stress, which is consistent with a previous theoretical result we have determined for flaw insensitivity during fibrillar pull-off. In addition, we measured the energy release rate required to fail the interface in the fibrillar region to be about an order of magnitude greater than that in the non-fibrillar region. We present experimental evidence demonstrating that this increase results partly from dissipation of strain energy stored in the fibrils.

  18. Biological Nitrogen Fixation In Tropical Dry Forests Of Costa Rica

    NASA Astrophysics Data System (ADS)

    Gei, M. G.; Powers, J. S.

    2012-12-01

    Evidence suggests that tropical dry forests (TDF) are not nitrogen (N) deficient. This evidence includes: high losses of gaseous nitrogen during the rainy season, high ecosystem soil N stocks and high N concentrations in leaves and litterfall. Its been commonly hypothesized that biological nitrogen fixation is responsible for the high availability of N in tropical soils. However, the magnitude of this flux has rarely if ever been measured in tropical dry forests. Because of the high cost of fixing N and the ubiquity of N fixing legume trees in the TDF, at the individual tree level symbiotic fixation should be a strategy down-regulated by the plant. Our main goal was to determine the rates of and controls over symbiotic N fixation. We hypothesized that legume tree species employ a facultative strategy of nitrogen fixation and that this process responds to changes in light availability, soil moisture and nutrient supply. We tested this hypothesis both on naturally established trees in a forest and under controlled conditions in a shade house by estimating the quantities of N fixed annually using the 15N natural abundance method, counting nodules, and quantifying (field) or manipulating (shade house) the variation in important environmental variables (soil nutrients, soil moisture, and light). We found that in both in our shade house experiment and in the forest, nodulation varied among different legume species. For both settings, the 15N natural abundance approach successfully detected differences in nitrogen fixation among species. The legume species that we studied were able to regulate fixation depending on the environmental conditions. They showed to have different strategies of nitrogen fixation that follow a gradient of facultative to obligate fixation. Our data suggest that there exists a continuum of nitrogen fixation strategies among species. Any efforts to define tropical legume trees as a functional group need to incorporate this variation.

  19. Biologically-inspired synthetic dry adhesives for wall-climbing robots

    NASA Astrophysics Data System (ADS)

    Murphy, Michael P.

    Animals such as insects, spiders, and lizards are capable of clinging to and climbing on a variety of surfaces, from rough stone to smooth silicon. Hairy microscale arrays of structures on their feet conform to surface roughness to create millions of points of contact, creating a large overall contact area. Weak intermolecular forces (van der Waals forces) between each fiber tip and the surface sum to large overall forces due to the high number of contacts. In this work we present the fabrication, characterization, and demonstration of synthetic polyurethane fibrillar adhesives inspired by these animals. Angled polymer micro-fiber arrays are fabricated and characterized. A tip modification technique is presented which enables fabrication of fibers with flat mushroom shaped tips which greatly increase the adhesion of the fibers, up to 5N/cm 2 (normal direction), and with a magnitude within the range of geckos (10 N/cm2) in the shear direction on smooth surfaces. We present a fabrication technique to create fibers with angled flat mushroom-shaped tips which replicate the directional characteristics of geckos, gripping in one direction (within the range of gecko adhesion) and releasing easily in the other. Multilevel hierarchical structures with specialized tips for roughness adaptation are also presented. Fiber hierarchies from the millimeter scale to the sub-micron scale are demonstrated, including three-level fiber fabrication with specialized tips. Hierarchical structures demonstrate up to 5 times the adhesion of an unstructured sample, and requiring up to 10 times the detachment energy. Finally, an agile, wireless, palm-sized wall climbing robot which uses the synthetic fibrillar dry adhesives to climb is presented. Waalbot , named after the van der Waals forces it uses to climb, exploits the attachment and detachment characteristics of the developed dry adhesives, capabilities include climbing smooth surfaces such as glass in any orientation on any surface slope

  20. THE STRUCTURE OF INSECT FIBRILLAR FLIGHT MUSCLE

    PubMed Central

    Smith, David S.

    1961-01-01

    The fine structure of fibrillar flight muscle of the mature adult beetle Tenebrio molitor is described. Although the very high frequency of contraction of fibrillar muscle has previously been in part accounted for as the result of mechanical specialization of the wing-bearing segment rather than of a correspondingly high rate of motor impulse supply, the problem of the nature of the pathway by which excitation is conducted into these large fibers remained. Therefore, particular attention has been given to the disposition and relationships of the plasma membrane and sarcoplasmic reticulum in this tissue. The invading tracheoles draw with them a sheath of plasma membrane from the surface to all depths in the fiber, and it is suggested that these sheaths, together with the extensive tubular arborisations arising from them, reduce the maximum plasma membrane-to-fibril distance from the radius of the fiber to a value of less than 2 µ. The evidence presented here confirms Veratti's contention that in fibrillar muscle the "reticulum" is associated with, though entirely distinct from the fibrils. Unlike other muscles so far examined, these flight muscle fibers contain a plasma membrane reticulum only, but it is possible that elsewhere the general "sarcoplasmic reticulum" includes a component derived from the plasma membrane, likewise acting as the pathway for inward conduction of excitation. Profiles of the internalised plasma membrane in Tenebrio showing the usual triple-layered 25-25-25 A organization are frequently seen, in sections, in close association with isolated vesicles (defined by "simple" 50 A membranes) which are here considered to represent, in vestigial form, the portion of the sarcoplasmic reticulum which in other types of muscle is complex and highly developed. Such associations, in Tenebrio, between these two dissimilar elements are here termed "dyads" and the possible morphological and functional homology between these and the "triads" of other types of

  1. Fibrillar dimer formation of islet amyloid polypeptides

    SciTech Connect

    Chiu, Chi -cheng; de Pablo, Juan J.

    2015-05-08

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 – 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 – 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  2. Tunable Friction Behavior of Photochromic Fibrillar Surfaces.

    PubMed

    Nanni, Gabriele; Ceseracciu, Luca; Oropesa-Nuñez, Reinier; Canale, Claudio; Salvatore, Princia; Fragouli, Despina; Athanassiou, Athanassia

    2015-06-01

    Grasslike compliant micro/nano crystals made of diarylethene (DAE) photochromic molecules are spontaneously formed on elastomer films after dipping them in a solution containing the photochromic molecules. The frictional forces of such micro- and nanofibrillar surfaces are reversibly tuned upon ultraviolet (UV) irradiation and dark storage cycles. This behavior is attributed to the Young's modulus variation of the single fibrils due to the photoisomerization process of the DAE molecules, as measured by advanced atomic force microscopy (AFM) techniques. In fact, a significant yet reversible decrease of the stiffness of the outer part of the fibrils in response to the UV light irradiation is demonstrated. The modification of the molecular structure of the fibrils influences their mechanical properties and affects the frictional behavior of the overall fibrillar surfaces. These findings provide the possibility to develop a system that controllably and accurately generates both low and high friction forces.

  3. Fibrillar dimer formation of islet amyloid polypeptides

    NASA Astrophysics Data System (ADS)

    Chiu, Chi-cheng; de Pablo, Juan J.

    2015-09-01

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 - 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 - 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimental and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.

  4. Mathematical simulation of electrophysical characteristics of multiply scattering media with a fibrillar structure. II. Numerical calculations

    NASA Astrophysics Data System (ADS)

    Kulikov, K. G.

    2013-11-01

    The optical characteristics (refractive index and absorption coefficient) of the biotissue being simulated (epidermis, upper layer of derma, lower layer of derma, and blood corpuscles) are obtained using the mathematical model constructed taking into account the fibrillar structure. The quantitative estimates based on this model can be used for predicting the variations in the optical properties of biological tissue samples, which are associated with various biophysical and biochemical processes occurring in it.

  5. New Method for Monitoring the Process of Freeze Drying of Biological Materials.

    PubMed

    Alkeev, Nikolay; Averin, Stanislav; von Gratowski, Svetlana

    2015-12-01

    A capacitive sensor was proposed and tested for the monitoring and control of a freeze drying process of a vaccine against the Newcastle disease of birds. The residual moisture of the vaccine was measured by the thermogravimetric method. The vaccine activity was determined by titration in chicken embryos. It was shown that, at the stages of freezing and primary drying, a capacitive sensor measured the fraction of unfrozen liquid phase in a material and allowed one to control the sublimation stage of drying in an optimal way. This prevented the foaming of the material and shortened the total drying time approximately twice. The control range at the sublimation stage of drying expanded up to -70°C. It was found at the final stage of drying that the signal of a capacitive sensor passed through a maximum value. We supposed that this maximum corresponds to the minimum of intramolecular mobility of biological macromolecules and hence to the optimal residual moisture of the material, which ensures long-term preservation of its activity. We also suppose that using the capacitive sensor at the final stage of drying allows one to more precisely detect the time when the residual moisture of dried material reaches the optimal value.

  6. Some biological and physical factors in dry heat sterilization: a general review.

    PubMed

    Bruch, C W

    1964-01-01

    There is a surprising lack of quantitative data on sterilization by dry heat so that microbiologists have little knowledge of the role played by various biological and physical factors in this sterilizing process. A recent investigation by the author has shown that the aerobic mesophilic bacterial sporeformers, such as Bacillus subtilis and Bacillus coagulans, are the most resistant among several species of sporeforming bacteria to dry heat sterilization. The type of carrier on which the spores are exposed to dry heat markedly affects their thermal resistance. An analysis of four carriers showed that spores on sand or vermiculite are more difficult to destroy than spores on paper or glass. Spores under low vacuums are more susceptible to dry heat sterilization than spores in helium, which are more susceptible than spores in air. Spores trapped in solids have thermal resistance levels two or three times greater than those found for spores exposed to dry heat in air. Preliminary results on the combination of dry heat and ionizing radiation sterilization indicate no synergistic effects, i.e., the destruction obtained with each agent is additive. Another important variable that governs the interpretation of the effectiveness of dry heat sterilization tests is the recovery medium for heat-damaged spores. The kinetics of dry heat sterilization cannot be fully interpreted from the available data. Death follows a logarithmic pattern thereby implying a monomolecular reaction. The mechanism of death is thought to be due to an oxidative process. PMID:11883444

  7. Fibrillar dimer formation of islet amyloid polypeptides

    DOE PAGES

    Chiu, Chi -cheng; de Pablo, Juan J.

    2015-05-08

    Amyloid deposits of human islet amyloid polypeptide (hIAPP), a 37-residue hormone co-produced with insulin, have been implicated in the development of type 2 diabetes. Residues 20 – 29 of hIAPP have been proposed to constitute the amyloidogenic core for the aggregation process, yet the segment is mostly unstructured in the mature fibril, according to solid-state NMR data. Here we use molecular simulations combined with bias-exchange metadynamics to characterize the conformational free energies of hIAPP fibrillar dimer and its derivative, pramlintide. We show that residues 20 – 29 are involved in an intermediate that exhibits transient β-sheets, consistent with recent experimentalmore » and simulation results. By comparing the aggregation of hIAPP and pramlintide, we illustrate the effects of proline residues on inhibition of the dimerization of IAPP. The mechanistic insights presented here could be useful for development of therapeutic inhibitors of hIAPP amyloid formation.« less

  8. Light-assisted drying (LAD) of small volume biologics: a comparison of two IR light sources

    NASA Astrophysics Data System (ADS)

    Young, Madison A.; Van Vorst, Matthew; Elliott, Gloria D.; Trammell, Susan R.

    2016-03-01

    Protein therapeutics have been developed to treat diseases ranging from arthritis and psoriasis to cancer. A challenge in the development of protein-based drugs is maintaining the protein in the folded state during processing and storage. We are developing a novel processing method, light-assisted drying (LAD), to dehydrate proteins suspended in a sugar (trehalose) solution for storage at supra-zero temperatures. Our technique selectively heats the water in small volume samples using near-IR light to speed dehydration which prevents sugar crystallization that can damage embedded proteins. In this study, we compare the end moisture content (EMC) as a function of processing time of samples dried with two different light sources, Nd:YAG (1064 nm) and Thulium fiber (1850 nm) lasers. EMC is the ratio of water to dry weight in a sample and the lower the EMC the higher the possible storage temperature. LAD with the 1064 and 1850 nm lasers yielded 78% and 65% lower EMC, respectively, than standard air-drying. After 40 minutes of LAD with 1064 and 1850 nm sources, EMCs of 0.27+/-.27 and 0.15+/-.05 gH2O/gDryWeight were reached, which are near the desired value of 0.10 gH2O/gDryWeight that enables storage in a glassy state without refrigeration. LAD is a promising new technique for the preparation of biologics for anhydrous preservation.

  9. Design of biomimetic fibrillar interfaces: 2. Mechanics of enhanced adhesion.

    PubMed

    Hui, C-Y; Glassmaker, N J; Tang, T; Jagota, A

    2004-11-22

    This study addresses the strength and toughness of generic fibrillar structures. We show that the stress sigmac required to pull a fibril out of adhesive contact with a substrate has the form sigma(c) = sigma(0)Phi(chi). In this equation, sigma(0) is the interfacial strength, Phi(chi) is a dimensionless function satisfying 0 1, but is flaw insensitive for chi < 1. The important parameter chi also controls the stability of a homogeneously deformed non-fibrillar (flat) interface. Using these results, we show that the work to fail a unit area of fibrillar surface can be much higher than the intrinsic work of adhesion for a flat interface of the same material. In addition, we show that cross-sectional fibril dimensions control the pull-off force, which increases with decreasing fibril radius. Finally, an increase in fibril length is shown to increase the work necessary to separate a fibrillar interface. Besides our calculations involving a single fibril, we study the concept of equal load sharing (ELS) for a perfect interface containing many fibrils. We obtain the practical work of adhesion for an idealized fibrillated interface under equal load sharing. We then analyse the peeling of a fibrillar surface from a rigid substrate and establish a criterion for ELS.

  10. Design of biomimetic fibrillar interfaces: 2. Mechanics of enhanced adhesion.

    PubMed Central

    Hui, C-Y; Glassmaker, N. J.; Tang, T.; Jagota, A.

    2004-01-01

    This study addresses the strength and toughness of generic fibrillar structures. We show that the stress sigmac required to pull a fibril out of adhesive contact with a substrate has the form sigma(c) = sigma(0)Phi(chi). In this equation, sigma(0) is the interfacial strength, Phi(chi) is a dimensionless function satisfying 0 > 1, but is flaw insensitive for chi < 1. The important parameter chi also controls the stability of a homogeneously deformed non-fibrillar (flat) interface. Using these results, we show that the work to fail a unit area of fibrillar surface can be much higher than the intrinsic work of adhesion for a flat interface of the same material. In addition, we show that cross-sectional fibril dimensions control the pull-off force, which increases with decreasing fibril radius. Finally, an increase in fibril length is shown to increase the work necessary to separate a fibrillar interface. Besides our calculations involving a single fibril, we study the concept of equal load sharing (ELS) for a perfect interface containing many fibrils. We obtain the practical work of adhesion for an idealized fibrillated interface under equal load sharing. We then analyse the peeling of a fibrillar surface from a rigid substrate and establish a criterion for ELS. PMID:16849151

  11. The gravimetric method for the determination of residual moisture in freeze-dried biological products.

    PubMed

    May, J C; Wheeler, R M; Grim, E

    1989-06-01

    The gravimetric test for the determination of residual moisture in freeze-dried biological products performed in a humidity- and temperature-controlled room with the use of scrupulous gravimetric analytical technique can be used to accurately determine residual moisture in freeze-dried biological products such as antihemophilic factor (human) or honey bee venom allergenic extract. This method determines the first water of hydration of sodium tartrate dihydrate (7.93%) to within 1.3% of the calculated value with a relative standard deviation of 0.3% for 10 replicates. For this gravimetric procedure, freeze-dried samples containing from 1.12 to 4.4% residual moisture had relative standard deviations ranging from 3.6 to 9.1%. Samples containing less than 1.0% residual moisture by the gravimetric method such as intravenous immune globulin and antihemophilic factor (human) had relative standard deviations ranging from 16.7 to 47.0%. Relative standard deviations for residual moisture tests performed on comparable samples by the Karl Fischer and thermogravimetric methods showed similar variability. PMID:2743789

  12. Friction Properties of Bio-mimetic Nano-fibrillar Arrays

    NASA Astrophysics Data System (ADS)

    Chen, Shao-Hua; Mi, Chun-Hui

    2009-10-01

    Nano-fibrillar arrays are fabricated using polystyrene materials. The average diameter of each fiber is about 300nm. Experiments show that such a fibrillar surface possesses a relatively hydrophobic feature with a water contact angle of 142°. Nanoscale friction properties are mainly focused on. It is found that the friction force of polystyrene nano-fibrillar surfaces is obviously enhanced in contrast to polystyrene smooth surfaces. The apparent coefficient of friction increases with the applied load, but is independent of the scanning speed. An interesting observation is that the friction force increases almost linearly with the real contact area, which abides by the fundamental Bowden-Tabor law of nano-scale friction.

  13. Soft grippers using micro-fibrillar adhesives for transfer printing.

    PubMed

    Song, Sukho; Sitti, Metin

    2014-07-23

    The adhesive characteristics of fibrillar adhesives on a soft deformable membrane are reported. A soft gripper with an inflatable membrane covered by elastomer mushroom-shaped microfibers have a superior conformation to non-planar 3D part geometries, enabling the transfer printing of various parts serially or in parallel.

  14. Tendon and ligament fibrillar crimps give rise to left-handed helices of collagen fibrils in both planar and helical crimps.

    PubMed

    Franchi, Marco; Ottani, Vittoria; Stagni, Rita; Ruggeri, Alessandro

    2010-03-01

    Collagen fibres in tendons and ligaments run straight but in some regions they show crimps which disappear or appear more flattened during the initial elongation of tissues. Each crimp is formed of collagen fibrils showing knots or fibrillar crimps at the crimp top angle. The present study analyzes by polarized light microscopy, scanning electron microscopy, transmission electron microscopy the 3D morphology of fibrillar crimp in tendons and ligaments of rat demonstrating that each fibril in the fibrillar region always twists leftwards changing the plane of running and sharply bends modifying the course on a new plane. The morphology of fibrillar crimp in stretched tendons fulfills the mechanical role of the fibrillar crimp acting as a particular knot/biological hinge in absorbing tension forces during fibril strengthening and recoiling collagen fibres when stretching is removed. The left-handed path of fibrils in the fibrillar crimp region gives rise to left-handed fibril helices observed both in isolated fibrils and sections of different tendons and ligaments (flexor digitorum profundus muscle tendon, Achilles tendon, tail tendon, patellar ligament and medial collateral ligament of the knee). The left-handed path of fibrils represents a new final suprafibrillar level of the alternating handedness which was previously described only from the molecular to the microfibrillar level. When the width of the twisting angle in the fibrillar crimp is nearly 180 degrees the fibrils appear as left-handed flattened helices forming crimped collagen fibres previously described as planar crimps. When fibrils twist with different subsequent rotational angles (< 180 degrees ) they always assume a left-helical course but, running in many different nonplanar planes, they form wider helical crimped fibres.

  15. Structure–Function Relationships of Pre-Fibrillar Protein Assemblies in Alzheimer's Disease and Related Disorders

    PubMed Central

    Rahimi, F.; Shanmugam, A.; Bitan, G.

    2010-01-01

    Several neurodegenerative diseases, including Alzheimer's, Parkinson's, Huntington's and prion diseases, are characterized pathognomonically by the presence of intra- and/or extracellular lesions containing proteinaceous aggregates, and by extensive neuronal loss in selective brain regions. Related non-neuropathic systemic diseases, e.g., light-chain and senile systemic amyloidoses, and other organ-specific diseases, such as dialysis-related amyloidosis and type-2 diabetes mellitus, also are characterized by deposition of aberrantly folded, insoluble proteins. It is debated whether the hallmark pathologic lesions are causative. Substantial evidence suggests that these aggregates are the end state of aberrant protein folding whereas the actual culprits likely are transient, pre-fibrillar assemblies preceding the aggregates. In the context of neurodegenerative amyloidoses, the proteinaceous aggregates may eventuate as potentially neuroprotective sinks for the neurotoxic, oligomeric protein assemblies. The pre-fibrillar, oligomeric assemblies are believed to initiate the pathogenic mechanisms that lead to synaptic dysfunction, neuronal loss, and disease-specific regional brain atrophy. The amyloid β-protein (Aβ), which is believed to cause Alzheimer's disease (AD), is considered an archetypal amyloidogenic protein. Intense studies have led to nominal, functional, and structural descriptions of oligomeric Aβ assemblies. However, the dynamic and metastable nature of Aβ oligomers renders their study difficult. Different results generated using different methodologies under different experimental settings further complicate this complex area of research and identification of the exact pathogenic assemblies in vivo seems daunting. Here we review structural, functional, and biological experiments used to produce and study pre-fibrillar Aβ assemblies, and highlight similar studies of proteins involved in related diseases. We discuss challenges that contemporary

  16. Creating internal conductivity in dry biological SEM samples by a simple vapour treatment.

    PubMed

    Ensikat, H-J; Weigend, M

    2014-12-01

    Internal sample conductivity in scanning electron microscopy can be a valuable alternative to metal coating. Proton conductivity may be used for this purpose. Many solid materials with active hydrogen atoms, such as hydrogen- and ammonium-salts, organic acids, and even ice, are protonic conductors or semiconductors. Here we present a method to generate proton conductivity in dry biological materials. A simple treatment with hydrogen chloride gas or hydrochloric acid vapour for a few minutes provides sufficient conductivity for many samples. After a removal of excess hydrogen chloride vapour with a vacuum desiccator, the objects may be examined in the SEM without metal coating. The use of internally conductive samples extends the range of easy-to-perform SEM preparation techniques. It is advantageous for material contrast imaging of uncoated samples, and it can be used in combination with metal coating to enhance conductivity on difficult samples with complex overlapping surfaces, where simple metal coating does not reliably eliminate charging problems. PMID:25204567

  17. Fibrillar films obtained from sodium soap fibers and polyelectrolyte multilayers.

    PubMed

    Zawko, Scott A; Schmidt, Christine E

    2011-08-01

    An objective of tissue engineering is to create synthetic polymer scaffolds with a fibrillar microstructure similar to the extracellular matrix. Here, we present a novel method for creating polymer fibers using the layer-by-layer method and sacrificial templates composed of sodium soap fibers. Soap fibers were prepared from neutralized fatty acids using a sodium chloride crystal dissolution method. Polyelectrolyte multilayers (PEMs) of polystyrene sulfonate and polyallylamine hydrochloride were deposited onto the soap fibers, crosslinked with glutaraldehyde, and then the soap fibers were leached with warm water and ethanol. The morphology of the resulting PEM structures was a dense network of fibers surrounded by a nonfibrillar matrix. Microscopy revealed that the PEM fibers were solid structures, presumably composed of polyelectrolytes complexed with residual fatty acids. These fibrillar PEM films were found to support the attachment of human dermal fibroblasts.

  18. Evaluation of Nanoparticle Tracking for Characterization of Fibrillar Protein Aggregates

    PubMed Central

    Yang, Dennis T.; Lu, Xiaomeng; Fan, Yamin; Murphy, Regina M.

    2015-01-01

    Amyloidogenesis is the process of formation of protein aggregates with fibrillar morphology. Because amyloidogenesis is linked to neurodegenerative disease, there is interest in understanding the mechanism of fibril growth. Kinetic models of amyloidogenesis require data on the number concentration and size distribution of aggregates, but this information is difficult to obtain using conventional methods. Nanoparticle tracking analysis (NTA) is a relatively new technique that may be uniquely suited for obtaining these data. In NTA, the two-dimensional (2-D) trajectory of individual particles is tracked, from which the diffusion coefficient, and, hence, hydrodynamic radius is obtained. Here we examine the validity of NTA in tracking number concentration and size of DNA, as a model of a fibrillar macromolecule. We use NTA to examine three amyloidogenic materials: beta-amyloid, transthyretin, and polyglutamine-containing peptides. Our results are instructive in demonstrating the advantages and some limitations of single-particle diffusion measurements for investigating aggregation in protein systems. PMID:25843955

  19. Nanoscale helium ion microscopic analysis of collagen fibrillar changes following femtosecond laser dissection of human cornea.

    PubMed

    Riau, Andri K; Poh, Rebekah; Pickard, Daniel S; Park, Chris H J; Chaurasia, Shyam S; Mehta, Jodhbir S

    2014-08-01

    Over the last decade, femtosecond lasers have emerged as an important tool to perform accurate and fine dissections with minimal collateral damage in biological tissue. The most common surgical procedure in medicine utilizing femtosecond laser is LASIK. During the femtosecond laser dissection process, the corneal collagen fibers inevitably undergo biomechanical and thermal changes on a sub-micro- or even a nanoscale level, which can potentially lead to post-surgical complications. In this study, we utilized helium ion microscopy, complemented with transmission electron microscopy to examine the femtosecond laser-induced collagen fibrillar damage in ex vivo human corneas. We found that the biomechanical damage induced by laser etching, generation of tissue bridges, and expansion of cavitation bubble and its subsequent collapse, created distortion to the surrounding collagen lamellae. Femtosecond laser-induced thermal damage was characterized by collapsed collagen lamellae, loss of collagen banding, collagen coiling, and presence of spherical debris. Our findings have shown the ability of helium ion microscopy to provide high resolution images with unprecedented detail of nanoscale fibrillar morphological changes in order to assess a tissue damage, which could not be resolved by conventional scanning electron microscopy previously. This imaging technology has also given us a better understanding of the tissue-laser interactions in a nano-structural manner and their possible effects on post-operative wound recovery. PMID:25016655

  20. Nanoscale helium ion microscopic analysis of collagen fibrillar changes following femtosecond laser dissection of human cornea.

    PubMed

    Riau, Andri K; Poh, Rebekah; Pickard, Daniel S; Park, Chris H J; Chaurasia, Shyam S; Mehta, Jodhbir S

    2014-08-01

    Over the last decade, femtosecond lasers have emerged as an important tool to perform accurate and fine dissections with minimal collateral damage in biological tissue. The most common surgical procedure in medicine utilizing femtosecond laser is LASIK. During the femtosecond laser dissection process, the corneal collagen fibers inevitably undergo biomechanical and thermal changes on a sub-micro- or even a nanoscale level, which can potentially lead to post-surgical complications. In this study, we utilized helium ion microscopy, complemented with transmission electron microscopy to examine the femtosecond laser-induced collagen fibrillar damage in ex vivo human corneas. We found that the biomechanical damage induced by laser etching, generation of tissue bridges, and expansion of cavitation bubble and its subsequent collapse, created distortion to the surrounding collagen lamellae. Femtosecond laser-induced thermal damage was characterized by collapsed collagen lamellae, loss of collagen banding, collagen coiling, and presence of spherical debris. Our findings have shown the ability of helium ion microscopy to provide high resolution images with unprecedented detail of nanoscale fibrillar morphological changes in order to assess a tissue damage, which could not be resolved by conventional scanning electron microscopy previously. This imaging technology has also given us a better understanding of the tissue-laser interactions in a nano-structural manner and their possible effects on post-operative wound recovery.

  1. Crystalline fibrillar gel formation in aqueous surfactant-antioxidant system.

    PubMed

    Joseph, Linet Rose; Tata, B V R; Sreejith, Lisa

    2015-08-01

    Cetyltrimethylammonium bromide (CTAB) is a well-known cationic surfactant capable to micellize into diverse morphologies in aqueous medium. We observed the formation of an opaque gel state from aqueous CTAB solution in the presence of the aromatic additive, para-coumaric acid (PCA). Optical microscopic images revealed the presence of large fibrils in the system at room temperature. Gel nature of the fibrils was confirmed by rheological measurements. Presence of interstitial water in the fibrils was recognized with Raman spectroscopy. On heating the sample above 30 (°) C, the fibrillar gel state changes to a transparent liquid state with Newtonian flow properties. Dynamic light scattering study hinted the presence of small micelles in the solution above 30 (°) C. Thus the system showed a temperature-dependent structural transition from opaque water-swollen gel to transparent micellar liquid. The formation of water-swollen fibrillar network is attributed to surfactant-additive intermolecular interactions in aqueous medium. Transition to micelle phase above 30 (°) C is related to Kraft transition which is observed at significantly lower temperature for CTAB in the absence of PCA. The structural features of PCA play a key role in promoting fibrillar network formation and elevating the Kraft transition in aqueous solution of CTAB.

  2. Fabrication and Characterization of Gecko-inspired Fibrillar Adhesive

    NASA Astrophysics Data System (ADS)

    Kim, Yongkwan

    Over the last decade, geckos' remarkable ability to stick to and climb surfaces found in nature has motivated a wide range of scientific interest in engineering gecko-mimetic surface for various adhesive and high friction applications. The high adhesion and friction of its pads have been attributed to a complex array of hairy structures, which maximize surface area for van der Waals interaction between the toes and the counter-surface. While advances in micro- and nanolithography technique have allowed fabrication of increasingly sophisticated gecko mimetic surfaces, it remains a challenge to produce an adhesive as robust as that of the natural gecko pads. In order to rationally design gecko adhesives, understanding the contact behavior of fibrillar interface is critical. The first chapter of the dissertation introduces gecko adhesion and its potential applications, followed by a brief survey of gecko-inspired adhesives. Challenges that limit the performance of the current adhesives are presented. In particular, it is pointed out that almost all testing of gecko adhesives have been on clean, smooth glass, which is ideal for adhesion due to high surface energy and low roughness. Surfaces in application are more difficult to stick to, so the understanding of failure modes in low energy and rough surfaces is important. The second chapter presents a fabrication method for thermoplastic gecko adhesive to be used for a detailed study of fibrillar interfaces. Low-density polyethylene nanofibers are replicated from a silicon nanowire array fabricated by colloidal lithography and metal-catalyzed chemical etching. This process yields a highly ordered array of nanofibers over a large area with control over fiber diameter, length, and number density. The high yield and consistency of the process make it ideal for a systematic study on factors that affect adhesion and friction of gecko adhesives. The following three chapters examine parameters that affect macroscale friction of

  3. A Dry Membrane Protection Technique to Allow Surface Acoustic Wave Biosensor Measurements of Biological Model Membrane Approaches

    PubMed Central

    Reder-Christ, Katrin; Schmitz, Patrick; Bota, Marian; Gerber, Ursula; Falkenstein-Paul, Hildegard; Fuss, Christian; Enachescu, Marius; Bendas, Gerd

    2013-01-01

    Model membrane approaches have attracted much attention in biomedical sciences to investigate and simulate biological processes. The application of model membrane systems for biosensor measurements is partly restricted by the fact that the integrity of membranes critically depends on the maintenance of an aqueous surrounding, while various biosensors require a preconditioning of dry sensors. This is for example true for the well-established surface acoustic wave (SAW) biosensor SAM®5 blue. Here, a simple drying procedure of sensor-supported model membranes is introduced using the protective disaccharide trehalose. Highly reproducible model membranes were prepared by the Langmuir-Blodgett technique, transferred to SAW sensors and supplemented with a trehalose solution. Membrane rehydration after dry incorporation into the SAW device becomes immediately evident by phase changes. Reconstituted model membranes maintain their full functionality, as indicated by biotin/avidin binding experiments. Atomic force microscopy confirmed the morphological invariability of dried and rehydrated membranes. Approximating to more physiological recognition phenomena, the site-directed immobilization of the integrin VLA-4 into the reconstituted model membrane and subsequent VCAM-1 ligand binding with nanomolar affinity were illustrated. This simple drying procedure is a novel way to combine the model membrane generation by Langmuir-Blodgett technique with SAW biosensor measurements, which extends the applicability of SAM®5 blue in biomedical sciences. PMID:24064603

  4. Biological monitoring of exposure to benzene in petrol pump workers and dry cleaners.

    PubMed

    Verma, Y; Rana, S V

    2001-10-01

    Exposure to benzene has been monitored in petrol-pump workers and dry cleaners of Meerut City (India) by measuring phenol content of their urine samples. Average values for phenol in urine were higher in petrol-pump workers than dry cleaners. Alcoholic subjects excreted more phenol than smokers and non-vegetarians. It is concluded that alcohol can alter the susceptibility of man to benzene toxicity by affecting its metabolism.

  5. The effect of fibrillar matrix architecture on tumor cell invasion of physically challenging environments.

    PubMed

    Guzman, Asja; Ziperstein, Michelle J; Kaufman, Laura J

    2014-08-01

    Local invasion by and dissemination of cancer cells from a primary tumor are key initial steps of metastasis, the most lethal aspect of cancer. To study these processes in vitro, the invasion of cells from multicellular breast cancer aggregates embedded in three-dimensional (3D) extracellular matrix culture systems was studied. This work showed that in 3D fibrillar environments composed of collagen I, pore size--not the viscoelastic properties of the matrix--was the biophysical characteristic controlling breast cancer cell invasion efficiency. Furthermore, it was shown that fibrillar matrix architecture is a crucial factor that allows for efficient 3D invasion. In a 3D non-fibrillar environment composed of basement membrane extract (BME), invasion efficiency was greatly diminished, the mesenchymal individual mode of 3D invasion was abolished, and establishment of cell polarity and protrusions was compromised. These effects were seen even though the BME matrix has invasion permissive viscoelasticity and suitable adhesion ligands. The altered and limited invasive behavior observed in BME was rescued through introduction of fibrillar collagen into the non-fibrillar matrix. The biophysical cues of fibrillar collagen facilitated efficient invasion of sterically disadvantageous environments through assisting cell polarization and formation of stable cell protrusions. Finally, we suggest the composite matrices employed in this study consisting of fibrillar collagen I and BME in either a liquid-like or gelled state are suitable for a wide range of 3D cell studies, as these matrices combine fibrillar features that require cells to deploy integrin-dependent mechanotransduction machinery and a tunable non-fibrillar component that may require cells to adopt alternative migratory modes.

  6. Elemental distribution and sample integrity comparison of freeze-dried and frozen-hydrated biological tissue samples with nuclear microprobe

    NASA Astrophysics Data System (ADS)

    Vavpetič, P.; Vogel-Mikuš, K.; Jeromel, L.; Ogrinc Potočnik, N.; Pongrac, P.; Drobne, D.; Pipan Tkalec, Ž.; Novak, S.; Kos, M.; Koren, Š.; Regvar, M.; Pelicon, P.

    2015-04-01

    The analysis of biological samples in frozen-hydrated state with micro-PIXE technique at Jožef Stefan Institute (JSI) nuclear microprobe has matured to a point that enables us to measure and examine frozen tissue samples routinely as a standard research method. Cryotome-cut slice of frozen-hydrated biological sample is mounted between two thin foils and positioned on the sample holder. The temperature of the cold stage in the measuring chamber is kept below 130 K throughout the insertion of the samples and the proton beam exposure. Matrix composition of frozen-hydrated tissue is consisted mostly of ice. Sample deterioration during proton beam exposure is monitored during the experiment, as both Elastic Backscattering Spectrometry (EBS) and Scanning Transmission Ion Microscopy (STIM) in on-off axis geometry are recorded together with the events in two PIXE detectors and backscattered ions from the chopper in a single list-mode file. The aim of this experiment was to determine differences and similarities between two kinds of biological sample preparation techniques for micro-PIXE analysis, namely freeze-drying and frozen-hydrated sample preparation in order to evaluate the improvements in the elemental localisation of the latter technique if any. In the presented work, a standard micro-PIXE configuration for tissue mapping at JSI was used with five detection systems operating in parallel, with proton beam cross section of 1.0 × 1.0 μm2 and a beam current of 100 pA. The comparison of the resulting elemental distributions measured at the biological tissue prepared in the frozen-hydrated and in the freeze-dried state revealed differences in elemental distribution of particular elements at the cellular level due to the morphology alteration in particular tissue compartments induced either by water removal in the lyophilisation process or by unsatisfactory preparation of samples for cutting and mounting during the shock-freezing phase of sample preparation.

  7. Carchesium stalk fibrillar matrix as a highly filled polymer network.

    PubMed

    Hawkes, R

    1977-01-01

    Glycerolated stalks of the sessile peritrich ciliate Carchesium sp. were treated with 10(-6) g ion/1 Ca2+ to disrupt the contractile spasmoneme. The resulting preparation consisted primarily of the fibrillar matrix, a dense extra-cellular meshwork of microfibrils. Some mechanical properties of this preparation have been investigated. The matrix tensile force-extension ratio relation for an initial stretch was characteristic of a soft, swollen polymer network, elastic modulus in young stalks 1.7 X 10(5) Nm-2, in mature stalks 4.0 X 10(5) Nm-2. The higher elastic modulus in mature stalks implies an increase in the interchain cross-link frequency. In young stalks, elastic modulus was found to be independent of the ambient Ca2+ concentration in the threshold range for spasmonemal contraction. Stalk relaxation was pronouncedly irreversible, showing stress softening and permanent hysteresis on repeated loading. Hysteresis was time independent and stiffness was not recovered after four hours at zero strain. Hysteresis was enhanced by repeated loading to the same tensile force. Stress-strain hysteresis at a low extension is characteristic of highly filled polymer networks in which polymer chains are interconnected via rigid filler particles as well as directly cross-linked.

  8. Innovative Manufacturing of Carbon Nanotube-Loaded Fibrillar Polymer Composites

    NASA Astrophysics Data System (ADS)

    Lin, R. J. T.; Bhattacharyya, D.; Fakirov, S.

    The concept of microfibrillar composite (MFC) has been used to create a new type of polymer composites, in which the reinforcing microfibrils are loaded with carbon nanotubes (CNT). Polyamide 66 (PA66) has been melt blended with polypropylene in a twin screw extruder with and without CNT, and thereafter cold drawn to create a fibrillar state as well as to align the CNT in the PA66 microfibrils. The drawn bristles were compression moulded at 180°C to prepare MFC plates. The scanning electron microscope (SEM) observations indicate near perfect distribution of CNT in the reinforcing PA66 microfibrils. Although the fibrillated PA66 is able to improve the tensile stiffness and strength as expected from the MFC structure, the incorporation of CNT does not exhibit any further enhancing effect. It rather adversely affects the mechanical properties due to poor interface adhesion between the matrix and the reinforcing microfibrils with the presence of CNT, as demonstrated by SEM. However, the resulting highly aligned CNT within the MFC are expected to affect the physical and functional properties of these composites.

  9. FibrilTool, an ImageJ plug-in to quantify fibrillar structures in raw microscopy images.

    PubMed

    Boudaoud, Arezki; Burian, Agata; Borowska-Wykręt, Dorota; Uyttewaal, Magalie; Wrzalik, Roman; Kwiatkowska, Dorota; Hamant, Olivier

    2014-02-01

    Cell biology heavily relies on the behavior of fibrillar structures, such as the cytoskeleton, yet the analysis of their behavior in tissues often remains qualitative. Image analysis tools have been developed to quantify this behavior, but they often involve an image pre-processing stage that may bias the output and/or they require specific software. Here we describe FibrilTool, an ImageJ plug-in based on the concept of nematic tensor, which can provide a quantitative description of the anisotropy of fiber arrays and their average orientation in cells, directly from raw images obtained by any form of microscopy. FibrilTool has been validated on microtubules, actin and cellulose microfibrils, but it may also help analyze other fibrillar structures, such as collagen, or the texture of various materials. The tool is ImageJ-based, and it is therefore freely accessible to the scientific community and does not require specific computational setup. The tool provides the average orientation and anisotropy of fiber arrays in a given region of interest (ROI) in a few seconds.

  10. From the Cover: Shape insensitive optimal adhesion of nanoscale fibrillar structures

    NASA Astrophysics Data System (ADS)

    Gao, Huajian; Yao, Haimin

    2004-05-01

    Gecko and many insects have adopted nanoscale fibrillar structures on their feet as adhesion devices. Here, we consider adhesion between a single fiber and a substrate by van der Waals or electrostatic interactions. For a given contact area A, the theoretical pull-off force of the fiber is thA where th is the theoretical strength of adhesion. We show that it is possible to design an optimal shape of the tip of the fiber to achieve the theoretical pull-off force. However, such design tends to be unreliable at the macroscopic scale because the pull-off force is sensitive to small variations in the tip shape. We find that a robust design of shape-insensitive optimal adhesion becomes possible only when the diameter of the fiber is reduced to length scales on the order of 100 nm. In general, optimal adhesion could be achieved by a combination of size reduction and shape optimization. The smaller the size, the less important the shape. At large contact sizes, optimal adhesion could still be achieved if the shape can be manufactured to a sufficiently high precision. The robust design of optimal adhesion at nanoscale provides a plausible explanation for the convergent evolution of hairy attachment systems in biology.

  11. Effect of biological treatment of the ceramic mass on the drying and firing of facing tiles

    SciTech Connect

    Baranov, V.V.; Sidorova, V.A.; Skripnik, V.P.; Solnyshkina, T.N.; Vainberg, S.N.; Vlasov, A.S.; Yashchenko, O.I.

    1985-12-01

    The authors studied the ceramic masses of the Minsk Building Materials Production complex (MZSM) and the Kishinev FinishingMaterials Plant (KZOM) having the following compositions: MZSM--48% Vesejovsk VGP clay, 22% nepheline concentrate, 17% quartz sand, 8% dolomite, 5% title scrap, and above 100% 3% bentonite, 0.1% soda ash, and 0.28% liquid glass; KZOM-48% Veselovsk VGP clay, 28% nepheline-syenite, 8% limestone filings (scrap), 16% title scrap, and, above 100%, 1% bentonite and 3% sodium tripolyphosphate. Improving the quality of ceramic tiles and reducing the mineral and fuel-energy consumption in their production are among the practical industrial problems. This paper discusses a method of solving them by improving the drying and firing processes of the products.

  12. RNA Profiling for the Identification of the Tissue Origin of Dried Stains in Forensic Biology.

    PubMed

    Hanson, E K; Ballantyne, J

    2010-07-01

    Examination of crime scene items for biological evidence typically begins with a preliminary screening for the presence of biological fluids in order to identify possible sources of DNA. Conventional biochemical and immunological assays employed for this screening require multiple tests to be performed in a serial manner, can consume a significant amount of valuable evidentiary material, and can require a significant amount of time and labor for completion. Moreover, the presence of several biological fluids, such as saliva, vaginal secretions, and menstrual blood, cannot be conclusively identified using current methods. Due to the disadvantages of conventional body fluid testing, some operational crime laboratories have chosen to bypass the body fluid identification process and proceed directly to DNA analysis. However, while reducing the time spent on each case, this "shortcut" could result in a failure to provide important probative information regarding the nature of the crime as well as result in increased cost to crime laboratories if unnecessary DNA testing is performed. In the past several years, a number of forensic researchers have attempted to develop molecular-based approaches to body fluid identification that would provide operational crime laboratories with significantly improved specificity. This has resulted in an increased interest in the use of RNA profiling strategies for the identification of forensically relevant biological fluids. This review provides an overview of studies carried out on the use of both messenger RNA and small (micro) RNA profiling. The results of these studies are encouraging and presage the routine identification the tissue source(s) of forensic evidence using molecular-based approaches.

  13. Influence of disturbance on soil respiration in biologically crusted soil during the dry season.

    PubMed

    Feng, Wei; Zhang, Yu-qing; Wu, Bin; Zha, Tian-shan; Jia, Xin; Qin, Shu-gao; Shao, Chen-xi; Liu, Jia-bin; Lai, Zong-rui; Fa, Ke-yu

    2013-01-01

    Soil respiration (Rs) is a major pathway for carbon cycling and is a complex process involving abiotic and biotic factors. Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. In desert ecosystems, soils are protected from surface disturbance by BSCs, but it is unknown whether Rs is affected by disturbance of this crust layer. We measured Rs in three types of disturbed and undisturbed crusted soils (algae, lichen, and moss), as well as bare land from April to August, 2010, in Mu Us desert, northwest China. Rs was similar among undisturbed soils but increased significantly in disturbed moss and algae crusted soils. The variation of Rs in undisturbed and disturbed soil was related to soil bulk density. Disturbance also led to changes in soil organic carbon and fine particles contents, including declines of 60-70% in surface soil C and N, relative to predisturbance values. Once BSCs were disturbed, Q 10 increased. Our findings indicate that a loss of BSCs cover will lead to greater soil C loss through respiration. Given these results, understanding the disturbance sensitivity impact on Rs could be helpful to modify soil management practices which promote carbon sequestration.

  14. Harnessing tunable scanning probe techniques to measure shear enhanced adhesion of gecko-inspired fibrillar arrays.

    PubMed

    Li, Yasong; Zhou, James H-W; Zhang, Cheng; Menon, Carlo; Gates, Byron D

    2015-02-01

    The hierarchical arrays of mesoscale to nanoscale fibrillar structures on a gecko's foot enable the animal to climb surfaces of varying roughness. Adhesion force between the fibrillar structures and various surfaces is maximized after the gecko drags its foot in one direction, which has also been demonstrated to improve the adhesion forces of artificial fibrillar arrays. Essential conditions that influence the magnitude of these interactions include the lateral distance traveled and velocity between the contacting surfaces, as well as the velocity at which the two surfaces are subsequently separated. These parameters have, however, not been systematically investigated to assess the adhesion properties of artificial adhesives. We introduce a systematic study that investigates these conditions using a scanning probe microscope to measure the adhesion forces of artificial adhesives through a process that mimics the mechanism by which a gecko climbs. The measured adhesion response was different for arrays of shorter and longer fibrils. These results from 9000 independent measurements also provide further insight into the dynamics of the interactions between fibrillar arrays and contacting surfaces. These studies establish scanning probe microscopy techniques as a versatile approach for measuring a variety of adhesion properties of artificial fibrillar adhesives.

  15. Contribution of glycosaminoglycans to the microstructural integrity of fibrillar and fiber crimps in tendons and ligaments.

    PubMed

    Franchi, Marco; De Pasquale, Viviana; Martini, Désirée; Quaranta, Marilisa; Macciocca, Maria; Dionisi, Alessio; Ottani, Vittoria

    2010-10-01

    The biomechanical roles of both tendons and ligaments are fulfilled by the extracellular matrix of these tissues. In particular, tension is mainly transmitted and resisted by protein (collagen, elastin) fibers, whereas compression is opposed by water-soluble glycosaminoglycans (GAGs). GAGs spanning the interfibrillar spaces and interacting with fibrils through the interfibrillar proteoglycans also seem to play a part in transmitting and resisting tensile stresses. Both tendons and ligaments showing similar composition, but different functional roles and collagen array, exhibit periodic undulations of collagen fibers or crimps. Each crimp is composed of many knots of each single fibril or fibrillar crimps. Fibrillar and fiber crimps play a mechanical role in absorbing the initial loading during elongation of both tendons and ligaments, and in recoiling fibrils and fibers when tissues have to return to their original length. This study investigated whether GAGs covalently attached to proteoglycan core proteins directly affect the 3D microstructural integrity of fibrillar crimp regions and fiber crimps in both tendons and ligaments. Achilles tendons and medial collateral ligaments of the knee from eight female Sprague-Dawley rats (90 days old) incubated in a chondroitinase ABC solution to remove GAGs were observed under a scanning electron microscope (SEM). In addition, isolated fibrils of these tissues obtained by mechanical disruption were analyzed by a transmission electron microscope (TEM). Both Achilles tendons and medial collateral ligaments of the rats after chemical or mechanical removal of GAGs still showed crimps and fibrillar crimps comparable to tissues with a normal GAG content. All fibrils in the fibrillar crimp region always twisted leftwards, thus changing their running plane, and then sharply bent, changing their course on a new plane. These data suggest that GAGs do not affect structural integrity or fibrillar crimp functions that seem mainly related

  16. Discrete contact mechanics of a fibrillar surface with backing layer interactions

    NASA Astrophysics Data System (ADS)

    Guidoni, G. M.; Schillo, D.; Hangen, U.; Castellanos, G.; Arzt, E.; McMeeking, R. M.; Bennewitz, R.

    2010-10-01

    The contact mechanics of a fibrillar micro-fabricated surface structure made of poly(dimethyl siloxane) (PDMS) is studied. The attachment and detachment of individual fibrils to and from a spherical indenter upon approach and retraction are detected as jumps in force and stiffness. A quantitative model describes the stiffness values by taking into account the deformation of the fibrils and the backing layer. The results emphasize the importance of long-range interactions in the contact mechanics of elastic materials and confirm some of the important concepts underlying the development of fibrillar adhesive materials.

  17. The effect of model soil contamination with Cr, Cu, Ni, and Pb on the biological properties of soils in the dry steppe and semidesert regions of southern Russia

    NASA Astrophysics Data System (ADS)

    Kolesnikov, S. I.; Spivakova, N. A.; Kazeev, K. Sh.

    2011-09-01

    Model soil contamination with Cr, Cu, Ni, and Pb in the dry steppes and semideserts of southern Russia has worsened the biological soil properties. With respect to the degree of deterioration of the biological properties, the soils can be arranged in the following sequence: dark chestnut soils > chestnut soils > light chestnut soils > brown semidesert soils > sandy brown semidesert soils. The sequence of metal oxides according to the adverse effect on the biological soil properties is as follows: CrO3 > CuO ≥ PbO ≥ NiO.

  18. Non-fibrillar amyloid-{beta} peptide reduces NMDA-induced neurotoxicity, but not AMPA-induced neurotoxicity

    SciTech Connect

    Niidome, Tetsuhiro; Goto, Yasuaki; Kato, Masaru; Wang, Pi-Lin; Goh, Saori; Tanaka, Naoki; Akaike, Akinori; Kihara, Takeshi; Sugimoto, Hachiro

    2009-09-04

    Amyloid-{beta} peptide (A{beta}) is thought to be linked to the pathogenesis of Alzheimer's disease. Recent studies suggest that A{beta} has important physiological roles in addition to its pathological roles. We recently demonstrated that A{beta}42 protects hippocampal neurons from glutamate-induced neurotoxicity, but the relationship between A{beta}42 assemblies and their neuroprotective effects remains largely unknown. In this study, we prepared non-fibrillar and fibrillar A{beta}42 based on the results of the thioflavin T assay, Western blot analysis, and atomic force microscopy, and examined the effects of non-fibrillar and fibrillar A{beta}42 on glutamate-induced neurotoxicity. Non-fibrillar A{beta}42, but not fibrillar A{beta}42, protected hippocampal neurons from glutamate-induced neurotoxicity. Furthermore, non-fibrillar A{beta}42 decreased both neurotoxicity and increases in the intracellular Ca{sup 2+} concentration induced by N-methyl-D-aspartate (NMDA), but not by {alpha}-amino-3-hydrozy-5-methyl-4-isoxazole propionic acid (AMPA). Our results suggest that non-fibrillar A{beta}42 protects hippocampal neurons from glutamate-induced neurotoxicity through regulation of the NMDA receptor.

  19. Cloning of an annelid fibrillar-collagen gene and phylogenetic analysis of vertebrate and invertebrate collagens.

    PubMed

    Sicot, F X; Exposito, J Y; Masselot, M; Garrone, R; Deutsch, J; Gaill, F

    1997-05-15

    Arenicola marina possesses cuticular and interstitial collagens, which are mostly synthesised by its epidermis. A cDNA library was constructed from the body wall. This annelid cDNA library was screened with a sea-urchin-collagen cDNA probe, and several overlapping clones were isolated. Nucleotide sequencing of these clones revealed an open reading frame of 2052 nucleotides. The translation product exhibits a triple helical domain of 138 Gly-Xaa-Yaa repeats followed by a 269-residue-long C-terminal non-collagenous domain (C-propeptide). The triple helical domain exhibits an imperfection that has been previously described in a peptide produced by cyanogen bromide digestion (CNBr peptide) of A. marina interstitial collagen. This imperfection occurs at the same place in the interstitial collagen of the vestimentiferan Riftia pachyptila. This identifies the clone as coding for the C-terminal part of a fibrillar collagen chain. It was called FAm1alpha, for fibrillar collagen 1alpha chain of A. marina. The non-collagenous domain possesses a structure similar to carboxy-terminal propeptides of fibrillar pro-alpha chains. Only six conserved cysteine residues are observed in A. marina compared with seven or eight in all other known C-propeptides. This provides information on the importance of disulfide bonds in C-propeptide interactions and in the collagen-assembly process. Phylogenetic studies indicate that the fibrillar collagen 1alpha chain of A. marina is homologous to the R. pachyptila interstitial collagen and that the FAm1alpha gene evolved independently from the other alpha-chain genes. Complementary analyses indicate that the vertebrate fibrillar collagen family is composed of two monophyletic subgroups with a specific position of the collagen type-V chains. PMID:9210465

  20. Mechanics of load-drag-unload contact cleaning of gecko-inspired fibrillar adhesives.

    PubMed

    Abusomwan, Uyiosa A; Sitti, Metin

    2014-10-14

    Contact self-cleaning of gecko-inspired synthetic adhesives with mushroom-shaped tips has been demonstrated recently using load-drag-unload cleaning procedures similar to that of the natural animal. However, the underlying mechanics of contact cleaning has yet to be fully understood. In this work, we present a detailed experiment of contact self-cleaning that shows that rolling is the dominant mechanism of cleaning for spherical microparticle contaminants, during the load-drag-unload procedure. We also study the effect of dragging rate and normal load on the particle rolling friction. A model of spherical particle rolling on an elastomer fibrillar adhesive interface is developed and agrees well with the experimental results. This study takes us closer to determining design parameters for achieving self-cleaning fibrillar adhesives.

  1. Automated determination of fibrillar structures by simultaneous model building and fiber diffraction refinement.

    PubMed

    Potrzebowski, Wojciech; André, Ingemar

    2015-07-01

    For highly oriented fibrillar molecules, three-dimensional structures can often be determined from X-ray fiber diffraction data. However, because of limited information content, structure determination and validation can be challenging. We demonstrate that automated structure determination of protein fibers can be achieved by guiding the building of macromolecular models with fiber diffraction data. We illustrate the power of our approach by determining the structures of six bacteriophage viruses de novo using fiber diffraction data alone and together with solid-state NMR data. Furthermore, we demonstrate the feasibility of molecular replacement from monomeric and fibrillar templates by solving the structure of a plant virus using homology modeling and protein-protein docking. The generated models explain the experimental data to the same degree as deposited reference structures but with improved structural quality. We also developed a cross-validation method for model selection. The results highlight the power of fiber diffraction data as structural constraints.

  2. Infrared nanospectroscopy characterization of oligomeric and fibrillar aggregates during amyloid formation

    NASA Astrophysics Data System (ADS)

    Ruggeri, F. S.; Longo, G.; Faggiano, S.; Lipiec, E.; Pastore, A.; Dietler, G.

    2015-07-01

    Amyloids are insoluble protein fibrillar aggregates. The importance of characterizing their aggregation has steadily increased because of their link to human diseases and material science applications. In particular, misfolding and aggregation of the Josephin domain of ataxin-3 is implicated in spinocerebellar ataxia-3. Infrared nanospectroscopy, simultaneously exploiting atomic force microscopy and infrared spectroscopy, can characterize at the nanoscale the conformational rearrangements of proteins during their aggregation. Here we demonstrate that we can individually characterize the oligomeric and fibrillar species formed along the amyloid aggregation. We describe their secondary structure, monitoring at the nanoscale an α-to-β transition, and couple these studies with an independent measurement of the evolution of their intrinsic stiffness. These results suggest that the aggregation of Josephin proceeds from the monomer state to the formation of spheroidal intermediates with a native structure. Only successively, these intermediates evolve into misfolded aggregates and into the final fibrils.

  3. Automated determination of fibrillar structures by simultaneous model building and fiber diffraction refinement.

    PubMed

    Potrzebowski, Wojciech; André, Ingemar

    2015-07-01

    For highly oriented fibrillar molecules, three-dimensional structures can often be determined from X-ray fiber diffraction data. However, because of limited information content, structure determination and validation can be challenging. We demonstrate that automated structure determination of protein fibers can be achieved by guiding the building of macromolecular models with fiber diffraction data. We illustrate the power of our approach by determining the structures of six bacteriophage viruses de novo using fiber diffraction data alone and together with solid-state NMR data. Furthermore, we demonstrate the feasibility of molecular replacement from monomeric and fibrillar templates by solving the structure of a plant virus using homology modeling and protein-protein docking. The generated models explain the experimental data to the same degree as deposited reference structures but with improved structural quality. We also developed a cross-validation method for model selection. The results highlight the power of fiber diffraction data as structural constraints. PMID:25961412

  4. Amphiphilic Beads as Depots for Sustained Drug Release Integrated into Fibrillar Scaffolds

    PubMed Central

    Gaharwar, Akhilesh K.; Mihaila, Silvia M.; Kulkarni, Ashish A.; Patel, Alpesh; Di Luca, Andrea; Reis, Rui L.; Gomes, Manuela E.; van Blitterswijk, Clemens; Moroni, Lorenzo; Khademhosseini, Ali

    2014-01-01

    Native extracellular matrix (ECM) is a complex fibrous structure loaded with bioactive cues that affects the surrounding cells. A promising strategy to mimicking native tissue architecture for tissue engineering applications is to engineer fibrous scaffolds using electrospinning. By loading appropriate bioactive cues within these fibrous scaffolds, various cellular functions such as cell adhesion, proliferation and differentiation can be regulated. Here, we report on the encapsulation and sustained release of model hydrophobic drug (dexamethasone (Dex)) within beaded fibrillar scaffold of poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT), a polyether-ester multiblock copolymer to direct differentiation of human mesenchymal stem cells (hMSCs). The amphiphilic beads act as depots for sustained drug release that is integrated into the fibrillar scaffolds. The entrapment of Dex within the beaded structure results in sustained release of drug over the period of 28 days. This is mainly attributed to the diffusion driven release of Dex from the amphiphilic electrospun scaffolds. In vitro results indicate that hMSCs cultured on Dex containing beaded fibrillar scaffolds exhibit an increase in osteogenic differentiation potential, as evidenced by increased alkaline phosphatase (ALP) activity, compared to the direct infusion of Dex in culture medium. The formation of mineralized matrix is also significantly enhanced due to the controlled Dex release from the fibrous scaffolds. This approach can be used to engineer scaffolds with appropriate chemical cues to direct tissue regeneration. PMID:24794894

  5. Biologically inspired polymer microfibers with spatulate tips as repeatable fibrillar adhesives

    NASA Astrophysics Data System (ADS)

    Kim, Seok; Sitti, Metin

    2006-12-01

    Being inspired by gecko foot hairs, microfibers with flat spatulate tips are proposed as repeatable adhesives. They are fabricated by molding a master template fabricated using deep reactive ion etching and the notching effect. Fabricated polyurethane fiber arrays with 4.5μm fiber and 9μm tip diameter demonstrated macroscale adhesion pressures up to 18N/cm2 and overall work of adhesion up to 11J/m2 on a 6mm diameter glass hemisphere for a preload pressure of 12N/cm2. These results show around four times higher adhesion and five times higher overall work of adhesion as compared to the flat polyurethane surface.

  6. Pre-fibrillar α-synuclein variants with impaired β-structure increase neurotoxicity in Parkinson's disease models

    PubMed Central

    Karpinar, Damla Pinar; Balija, Madhu Babu Gajula; Kügler, Sebastian; Opazo, Felipe; Rezaei-Ghaleh, Nasrollah; Wender, Nora; Kim, Hai-Young; Taschenberger, Grit; Falkenburger, Björn H; Heise, Henrike; Kumar, Ashutosh; Riedel, Dietmar; Fichtner, Lars; Voigt, Aaron; Braus, Gerhard H; Giller, Karin; Becker, Stefan; Herzig, Alf; Baldus, Marc; Jäckle, Herbert; Eimer, Stefan; Schulz, Jörg B; Griesinger, Christian; Zweckstetter, Markus

    2009-01-01

    The relation of α-synuclein (αS) aggregation to Parkinson's disease (PD) has long been recognized, but the mechanism of toxicity, the pathogenic species and its molecular properties are yet to be identified. To obtain insight into the function different aggregated αS species have in neurotoxicity in vivo, we generated αS variants by a structure-based rational design. Biophysical analysis revealed that the αS mutants have a reduced fibrillization propensity, but form increased amounts of soluble oligomers. To assess their biological response in vivo, we studied the effects of the biophysically defined pre-fibrillar αS mutants after expression in tissue culture cells, in mammalian neurons and in PD model organisms, such as Caenorhabditis elegans and Drosophila melanogaster. The results show a striking correlation between αS aggregates with impaired β-structure, neuronal toxicity and behavioural defects, and they establish a tight link between the biophysical properties of multimeric αS species and their in vivo function. PMID:19745811

  7. Dry Mouth

    MedlinePlus

    ... of this page please turn Javascript on. Dry Mouth What Is Dry Mouth? Dry mouth is the feeling that there is ... when a person has dry mouth. How Dry Mouth Feels Dry mouth can be uncomfortable. Some people ...

  8. Fibrillar polysaccharides in marine macromolecular organic matter as imaged by atomic force microscopy and transmission electron microscopy

    SciTech Connect

    Santschi, P.H.; Balnois, E.; Wilkinson, K.J.; Zhang, J.; Buffle, J.; Guo, L.

    1998-07-01

    A consensus is now emerging that the structure of organic macromolecules will determine their function in aquatic systems. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) are highly complementary techniques for the study of natural colloids and can, when used together, reveal complementary information about the relative abundance and structures of aquatic macromolecules and colloids. In this study, colloid samples from the Gulf of Mexico and Middle Atlantic Bight of nominal sizes 1--200 nm were collected by cross-flow ultrafiltration, diafiltered, and freeze-dried. Rehydrated colloids were analyzed in parallel by AFM and TEM using standardized techniques. Results from estuarine, surface-, and deep-water samples show that an important fraction of colloidal organic matter (COM) consists of fibrillar material, which is rich in polysaccharides and fresher (i.e., has a younger radiocarbon age) than the bulk COM. This result is important because COM makes up 30--70% of oceanic and estuarine nominally dissolved organic matter. Other microparticles appear to be quasi-spherical, often attached to the fibrils like pearls. In the surface waters of the Gulf of Mexico, Middle Atlantic Bight, and Trinity River, fibrils with diameters of 1--3 nm and lengths of 100--2,000 nm were predominant. Although fibrils were also observed in samples from the benthic nepheloid layer in the Gulf of Mexico (1,600 m) and Middle Atlantic Bight (2,600 m), a much greater heterogeneity of colloid and macromolecule shapes and sizes was observed in these deeper waters.

  9. PHBV/PLLA-based composite scaffolds fabricated using an emulsion freezing/freeze-drying technique for bone tissue engineering: surface modification and in vitro biological evaluation.

    PubMed

    Sultana, Naznin; Wang, Min

    2012-03-01

    Tissue engineering combines living cells with biodegradable materials and/or bioactive components. Composite scaffolds containing biodegradable polymers and nanosized osteoconductive bioceramic with suitable properties are promising for bone tissue regeneration. In this paper, based on blending two biodegradable and biocompatible polymers, namely poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(L-lactic acid) (PLLA) with incorporated nano hydroxyapatite (HA), three-dimensional composite scaffolds with controlled microstructures and an interconnected porous structure, together with high porosity, were fabricated using an emulsion freezing/freeze-drying technique. The influence of various parameters involved in the emulsion freezing/freeze-drying technique was studied for the fabrication of good-quality polymer scaffolds based on PHBV polymers. The morphology, mechanical properties and crystallinity of PHBV/PLLA and HA in PHBV/PLLA composite scaffolds and PHBV polymer scaffolds were studied. The scaffolds were coated with collagen in order to improve wettability. During in vitro biological evaluation study, it was observed that SaOS-2 cells had high attachment on collagen-coated scaffolds. Significant improvement in cell proliferation and alkaline phosphatase activity for HA-incorporated composite scaffolds was observed due to the incorporation of HA. After 3 and 7 days of culture on all scaffolds, SaOS-2 cells also had normal morphology and growth. These results indicated that PHBV/PLLA-based scaffolds fabricated via an emulsion freezing/freeze-drying technique were favorable sites for osteoblastic cells and are promising for the applications of bone tissue engineering.

  10. Biologic comparison of inhaled insulin formulations: Exubera™ and novel spray-dried engineered particles of dextran-10.

    PubMed

    Kuehl, Philip J; Cherrington, Alan; Dobry, Dan E; Edgerton, Dale; Friesen, Dwayne T; Hobbs, Charles; Leach, Chet L; Murri, Brice; Neal, Doss; Lyon, David K; Vodak, David T; Reed, Matthew D

    2014-12-01

    Inhaled peptides and proteins have promise for respiratory and systemic disease treatment. Engineered spray-dried powder formulations have been shown to stabilize peptides and proteins and optimize aerosol properties for pulmonary delivery. The current study was undertaken to investigate the in vitro and in vivo inhalation performance of a model spray-dried powder of insulin and dextran 10 in comparison to Exubera™. Dextrans are a class of glucans that are generally recognized as safe with optimum glass transition temperatures well suited for spray drying. A 70% insulin particle loading was prepared by formulating with 30% (w/v) dextran 10. Physical characterization revealed a "raisin like" particle. Both formulations were generated to produce a similar bimodal particle size distribution of less than 3.5 μm MMAD. Four female Beagle dogs were exposed to each powder in a crossover design. Similar presented and inhaled doses were achieved with each powder. Euglycemia was achieved in each dog prior and subsequent to dosing and blood samples were drawn out to 245 min post-exposure. Pharmacokinetic analyses of post-dose insulin levels were similar for both powders. Respective dextran 10-insulin and Exubera exposures were similar producing near identical area under the curve (AUC), 7,728 ± 1,516 and 6,237 ± 2,621; concentration maximums (C max), 126 and 121 (μU/mL), and concentration-time maximums, 20 and 14 min, respectively. These results suggest that dextran-10 and other dextrans may provide a novel path for formulating peptides and proteins for pulmonary delivery.

  11. Reaction diffusion model of the enzymatic erosion of insoluble fibrillar matrices.

    PubMed Central

    Tzafriri, Abraham R; Bercovier, Michel; Parnas, Hanna

    2002-01-01

    Predicting the time course of in vivo biodegradation is a key issue in the design of an increasing number of biomedical applications such as sutures, tissue analogs and drug-delivery devices. The design of such biodegradable devices is hampered by the absence of quantitative models for the enzymatic erosion of solid protein matrices. In this work, we derive and simulate a reaction diffusion model for the enzymatic erosion of fibrillar gels that successfully reproduces the main qualitative features of this process. A key aspect of the proposed model is the incorporation of steric hindrance into the standard Michaelis-Menten scheme for enzyme kinetics. In the limit of instantaneous diffusion, the model equations are analogous to the standard equations for enzymatic degradation in solution. Invoking this analogy, the total quasi-steady-state approximation is used to derive approximate analytical solutions that are valid for a wide range of in vitro conditions. Using these analytical approximations, an experimental-theoretical method is derived to unambiguously estimate all the kinetic model parameters. Moreover, the analytical approximations correctly describe the characteristic hyperbolic dependence of the erosion rate on enzyme concentration and the zero-order erosion of thin fibers. For definiteness, the analysis of published experimental results of enzymatic degradation of fibrillar collagen is demonstrated, and the role of diffusion in these experiments is elucidated. PMID:12124264

  12. Influence of collagen source on fibrillar architecture and properties of vitrified collagen membranes.

    PubMed

    Majumdar, Shoumyo; Guo, Qiongyu; Garza-Madrid, Marcos; Calderon-Colon, Xiomara; Duan, Derek; Carbajal, Priscilla; Schein, Oliver; Trexler, Morgana; Elisseeff, Jennifer

    2016-02-01

    Collagen vitrigel membranes are transparent biomaterials characterized by a densely organized, fibrillar nanostructure that show promise in the treatment of corneal injury and disease. In this study, the influence of different type I collagen sources and processing techniques, including acid-solubilized collagen from bovine dermis (Bov), pepsin-solubilized collagen from human fibroblast cell culture (HuCC), and ficin-solubilized collagen from recombinant human collagen expressed in tobacco leaves (rH), on the properties of the vitrigel membranes was evaluated. Postvitrification carbodiimide crosslinking (CX) was also carried out on the vitrigels from each collagen source, forming crosslinked counterparts BovXL, HuCCXL, and rHXL, respectively. Collagen membrane ultrastructure and biomaterial properties were found to rely heavily on both collagen source and crosslinking. Bov and HuCC samples showed a random fibrillar organization of collagen, whereas rH vitrigels showed remarkable regional fibril alignment. After CX, light transmission was enhanced in all groups. Denaturation temperatures after CX increased in all membranes, of which the highest increase was seen in rH (14.71°C), suggesting improved thermal stability of the collagen fibrils in the membranes. Noncrosslinked rH vitrigels may be reinforced through CX to reach levels of mechanical strength and thermal stability comparable to Bov.

  13. Dense fibrillar collagen is a potent inducer of invadopodia via a specific signaling network

    PubMed Central

    Swatkoski, Stephen; Matsumoto, Kazue; Campbell, Catherine B.; Petrie, Ryan J.; Dimitriadis, Emilios K.; Li, Xin; Mueller, Susette C.; Bugge, Thomas H.; Gucek, Marjan

    2015-01-01

    Cell interactions with the extracellular matrix (ECM) can regulate multiple cellular activities and the matrix itself in dynamic, bidirectional processes. One such process is local proteolytic modification of the ECM. Invadopodia of tumor cells are actin-rich proteolytic protrusions that locally degrade matrix molecules and mediate invasion. We report that a novel high-density fibrillar collagen (HDFC) matrix is a potent inducer of invadopodia, both in carcinoma cell lines and in primary human fibroblasts. In carcinoma cells, HDFC matrix induced formation of invadopodia via a specific integrin signaling pathway that did not require growth factors or even altered gene and protein expression. In contrast, phosphoproteomics identified major changes in a complex phosphosignaling network with kindlin2 serine phosphorylation as a key regulatory element. This kindlin2-dependent signal transduction network was required for efficient induction of invadopodia on dense fibrillar collagen and for local degradation of collagen. This novel phosphosignaling mechanism regulates cell surface invadopodia via kindlin2 for local proteolytic remodeling of the ECM. PMID:25646088

  14. Humidity-enhanced wet adhesion on insect-inspired fibrillar adhesive pads

    PubMed Central

    Xue, Longjian; Kovalev, Alexander; Eichler-Volf, Anna; Steinhart, Martin; Gorb, Stanislav N.

    2015-01-01

    Many insect species reversibly adhere to surfaces by combining contact splitting (contact formation via fibrillar contact elements) and wet adhesion (supply of liquid secretion via pores in the insects’ feet). Here, we fabricate insect-inspired fibrillar pads for wet adhesion containing continuous pore systems through which liquid is supplied to the contact interfaces. Synergistic interaction of capillarity and humidity-induced pad softening increases the pull-off force and the work of adhesion by two orders of magnitude. This increase and the independence of pull-off force on the applied load are caused by the capillarity-supported formation of solid–solid contact between pad and the surface. Solid–solid contact dominates adhesion at high humidity and capillarity at low humidity. At low humidity, the work of adhesion strongly depends on the amount of liquid deposited on the surface and, therefore, on contact duration. These results may pave the way for the design of insect-inspired adhesive pads. PMID:25791574

  15. Bis-GMA/TEGDMA Dental Composites Reinforced with Electrospun Nylon 6 Nanocomposite Nanofibers Containing Highly Aligned Fibrillar Silicate Single Crystals.

    PubMed

    Tian, Ming; Gao, Yi; Liu, Yi; Liao, Yiliang; Xu, Riwei; Hedin, Nyle E; Fong, Hao

    2007-04-24

    The objective of this research was to study the reinforcement of electrospun nylon 6/fibrillar silicate nanocomposite nanofibers on Bis-GMA/TEGDMA dental composites. The hypothesis was that the uniform distribution of nano-scaled and highly aligned fibrillar silicate single crystals into electrospun nylon 6 nanofibers would improve the mechanical properties of the resulting nanocomposite nanofibers, and would lead to the effective reinforcement of dental composites. The nylon 6/fibrillar silicate nanocomposite nanofibers were crystalline, structurally oriented and had an average diameter of approximately 250 nm. To relatively well distribute nanofibers in dental composites, the nanofiber containing composite powders with a particle structure similar to that in interpenetration networks were prepared first, and then used to make the dental composites. The results indicated that small mass fractions (1 % and 2 %) of nanofiber impregnation improved the mechanical properties substantially, while larger mass factions (4 % and 8 %) of nanofiber impregnation resulted in less desired mechanical properties.

  16. Complex formation of blueberry (Vaccinium angustifolium) anthocyanins during freeze-drying and its influence on their biological activity.

    PubMed

    Correa-Betanzo, Julieta; Padmanabhan, Priya; Corredig, Milena; Subramanian, Jayasankar; Paliyath, Gopinadhan

    2015-03-25

    Biological activity of polyphenols is influenced by their uptake and is highly influenced by their interactions with the food matrix. This study evaluated the complex formation of blueberry polyphenols with fruit matrixes such as pectin and cellulose and their effect on the biological and antiproliferative properties of human colon cell lines HT-29 and CRL 1790. Free or complexed polyphenols were isolated by dialyzing aqueous or methanolic blueberry homogenates. Seven phenolic compounds and thirteen anthocyanins were identified in blueberry extracts. Blueberry extracts showed varying degrees of antioxidant and antiproliferative activities, as well as α-glucosidase activity. Fruit matrix containing cellulose and pectin, or purified polygalacturonic acid and cellulose, did not retain polyphenols and showed very low antioxidant or antiproliferative activities. These findings suggest that interactions between polyphenols and the food matrix may be more complex than a simple association and may play an important role in the bioefficacy of blueberry polyphenols. PMID:25727778

  17. Complex formation of blueberry (Vaccinium angustifolium) anthocyanins during freeze-drying and its influence on their biological activity.

    PubMed

    Correa-Betanzo, Julieta; Padmanabhan, Priya; Corredig, Milena; Subramanian, Jayasankar; Paliyath, Gopinadhan

    2015-03-25

    Biological activity of polyphenols is influenced by their uptake and is highly influenced by their interactions with the food matrix. This study evaluated the complex formation of blueberry polyphenols with fruit matrixes such as pectin and cellulose and their effect on the biological and antiproliferative properties of human colon cell lines HT-29 and CRL 1790. Free or complexed polyphenols were isolated by dialyzing aqueous or methanolic blueberry homogenates. Seven phenolic compounds and thirteen anthocyanins were identified in blueberry extracts. Blueberry extracts showed varying degrees of antioxidant and antiproliferative activities, as well as α-glucosidase activity. Fruit matrix containing cellulose and pectin, or purified polygalacturonic acid and cellulose, did not retain polyphenols and showed very low antioxidant or antiproliferative activities. These findings suggest that interactions between polyphenols and the food matrix may be more complex than a simple association and may play an important role in the bioefficacy of blueberry polyphenols.

  18. Orotic acid quantification in dried blood spots and biological fluids by hydrophilic interaction liquid chromatography tandem mass spectrometry.

    PubMed

    D'Apolito, Oceania; Garofalo, Daniela; Paglia, Giuseppe; Zuppaldi, Alfredo; Corso, Gaetano

    2010-03-01

    Orotic acid (ORA) is an intermediate metabolite in the pathway of pyrimidine nucleotides; its urinary excretion is useful to diagnose the hereditary orotic aciduria and some hyperammonemic inherited defects of urea cycle enzymes and amino acid transporters. ORA analysis is based on stable isotope dilution by GC-MS or LC-MS/MS methods. We developed a fast assay that measures the ORA in dried blood spots (DBS), plasma and urine using hydrophilic interaction LC-MS/MS. Within- and between-day analytical imprecision (CV%) of three quality control levels, in plasma, DBS and urine, ranged from 0.8 to 14.1%, while the inaccuracy ranged from -13.5 to 9.4%. In healthy children (n=20), ORA concentrations were less than 0.69 microM in plasma, less than 0.82 microM in DBS and from 0.2 to 1.4 mmol/mol of creatinine in urine. A patient with citrullinemia showed ORA levels of 133 microM in plasma and 39 microM in DBS. A patient with hyperammonemia-hyperornithinemia-homocitrullinemia (HHH) syndrome presented a urinary ORA level of 9.1 mmol/mol of creatinine. The method is potentially able to discriminate affected patients from reference subjects; the clinical validation should be expanded on a higher number of patients. PMID:20209505

  19. Governing biological material at the intersection of care and research: the use of dried blood spots for biobanking.

    PubMed

    Douglas, Conor M W; van El, Carla G; Faulkner, Alex; Cornel, Martina C

    2012-08-01

    A series of governance issues currently surrounds the multiple uses and multiple users of dried blood spots (DBS) for research purposes. Internationally there is a discussion on storing DBS resulting from newborn screening for public health and using them as the basis for large biobank-like collections to facilitate biomedical research. If such a transformation were to be formalized, then DBS would sit at the intersection of care (ie, public health) and research, with the mechanisms through which such a collection could be managed not totally self-evident. What is more, a DBS collection raises questions about the fuzzy boundaries between privacy and anonymity; how to control or define quality control uses of DBS; medical vs nonmedical uses; as well as benefit sharing and stakeholder involvement. Our goal here is to explore some of the key questions relating to DBS governance by way of the bio-objects and bio-objectification concepts. By embracing - rather than resisting to - the blurring of boundaries and problems in categorization that have come to characterize bio-objects and bio-objectification processes recently described in this journal, we attempt to highlight some issues that might not be currently considered, and to point to some possible directions to go (or avoid). Building from our knowledge of the current DBS situation in the Netherlands, we outline questions concerning the uses, management, collection, and storage of DBS.

  20. STUDIES ON PERMEABILITY OF MEMBRANES : VI. MENSURATION OF THE DRIED COLLODION MEMBRANE (CALCULATION OF DIMENSIONS AND OF RELATIONS TO CERTAIN BIOLOGICAL MEMBRANES).

    PubMed

    Weech, A A; Michaelis, L

    1928-11-20

    The flat type of dried collodion membrane used by Michaelis and his associates in numerous investigations has been subjected to mensuration in order that the dimensions of these membranes may be placed on record. The membranes had a functioning area of about 30 cm., were approximately 0.1 mm. in thickness and were composed on the average of 87 per cent by volume of collodion and 13 per cent by volume of pores. In reviewing some of the previously reported results of diffusion experiments with non-electrolytes in the light of the calculated values for the total pore area for the same membranes additional evidence was presented to show that a smaller molecule (acetone) probably utilizes a much larger percentage of the total pore area for its diffusion than is available for a larger molecule (glycerol). By using the figures of Fricke and McClendon for the thickness of the membrane of the red blood cell some comparisons were drawn between the dried collodion membrane as a model for certain biological membranes and the red blood cell membrane. In these comparisons emphasis was placed on the exaggerated importance of small electromotive forces and very slight permeabilities when these were associated with membranes of such extreme thinness as the red blood cell membrane.

  1. Superhydrophobic and oleophilic open-cell foams from fibrillar blends of polypropylene and polytetrafluoroethylene.

    PubMed

    Rizvi, Ali; Chu, Raymond K M; Lee, Jung H; Park, Chul B

    2014-12-10

    Effective removal of oils from water is of global significance for environmental protection. In this study, we investigate the hydrophobicity and oleophilicity of open-cell polymer foams prepared in a continuous and scalable extrusion process. The material used to prepare the open-cell foams is a fibrillar blend of polypropylene (PP) and polytetrafluoroethylene (PTFE). Scanning electron microscopy (SEM) images of the morphology of the PP/PTFE fibrillar blend reveal that the PTFE has a fibrillar morphology in the PP matrix. SEM micrograph of the extruded foam shows the formation of an interconnected open-cell structure. Using nitrogen pycnometry, the open-cell content is estimated to be 97.7%. A typical bulk density of the open-cell foam is measured to be about 0.07 g cm(-3) corresponding to a void fraction of 92%. Thus, a large three-dimensional space is made available for oil storage. A drop of water on the cross-section of the extruded open-cell foam forms a contact angle of 160° suggesting that the open-cell foam exhibits superhydrophobicity. The open-cell foam can selectively absorb various petroleum products, such as octane, gasoline, diesel, kerosene, light crude oil, and heavy crude oil from water and the uptake capacities range from about 5 to 24 g g(-1). The uptake kinetics can be enhanced by exposing the open-cell foam to high intensity ultrasound which increases the surface porosity of the thin, impervious, foam "skin" layer. The reusability of the foam can be improved by using a matrix polymer which demonstrates superior elastic properties and prevents the foams from undergoing a large permanent deformation upon compression to "squeeze out" the oil. For example, when the PP homopolymer matrix is replaced with a PP random copolymer, the permanent deformation for 10 compressive cycles is reduced from about 30% to 10%. To the best of our knowledge, these PP-based open-cell foams outperform PP-based absorbents conventionally used for oil-spill cleanup

  2. A biologically active delivery material with dried-rehydrated vesicles containing the anti-inflammatory diclofenac for potential wound healing.

    PubMed

    Ferreira, Helena; Silva, Raquel; Matamá, Teresa; Silva, Carla; Gomes, Andreia C; Cavaco-Paulo, Artur

    2016-12-01

    Chronic wounds usually remain in the inflammatory phase of the healing process during several months or even years. Hence, a continuous research has been resulting in the development of wound dressings with improved performance. Herein, we report a delivery system for cutaneous wound healing, consisting of a textile material (non-woven gauzes) covered with lipidic vesicles containing diclofenac, a non-steroidal anti-inflammatory drug (NSAID). This study also aims to compare the entrapment efficiency data with previous works and confirm that this parameter and drug amount are not directly correlated. A method of dehydration-rehydration of the liposomes presenting different sizes and lamellarities was used to assess the best conditions to attain the highest drug entrapment efficiency. Optimum conditions for the NSAID release were achieved with high phospholipid concentrations and dried-rehydrated vesicles (DRVs) prepared from multilamellar liposomes (MLVs). A chemical activation of the gauzes was performed to enhance the vesicles attachment, also contributing to a higher drug amount in the surrounding media. In spite of the entrapment efficiency being lower comparatively with other values presented by us previously, the diclofenac concentration was considerably higher in this formulation. Entrapment efficiency is, therefore, not sufficient per se to define the real amount of drug contained in the formulation. The cytocompatibility assessment in human skin fibroblasts showed that DRVs from MLVs and DRVs from large unilamellar liposomes (LUVs) with less than 750 μM of egg-yolk phosphatidylcholine (EPC), containing diclofenac, were not cytotoxic after 72 h of contact, greatly implying potential for their application in the chronic wounds healing. PMID:26634871

  3. Cell-mediated fiber recruitment drives extracellular matrix mechanosensing in engineered fibrillar microenvironments

    PubMed Central

    Baker, Brendon M.; Trappmann, Britta; Wang, William Y.; Sakar, Mahmut S.; Kim, Iris L.; Shenoy, Vivek B.; Burdick, Jason A.; Chen, Christopher S.

    2015-01-01

    To investigate how cells sense stiffness in settings structurally similar to native extracellular matrices (ECM), we designed a synthetic fibrous material with tunable mechanics and user-defined architecture. In contrast to flat hydrogel surfaces, these fibrous materials recapitulated cell-matrix interactions observed with collagen matrices including stellate cell morphologies, cell-mediated realignment of fibers, and bulk contraction of the material. While increasing the stiffness of flat hydrogel surfaces induced mesenchymal stem cell spreading and proliferation, increasing fiber stiffness instead suppressed spreading and proliferation depending on network architecture. Lower fiber stiffness permitted active cellular forces to recruit nearby fibers, dynamically increasing ligand density at the cell surface and promoting the formation of focal adhesions and related signaling. These studies demonstrate a departure from the well-described relationship between material stiffness and spreading established with hydrogel surfaces, and introduce fiber recruitment as a novel mechanism by which cells probe and respond to mechanics in fibrillar matrices. PMID:26461445

  4. Characterization of fibrillar collagen types using multi-dimensional multiphoton laser scanning microscopy.

    PubMed

    Lutz, V; Sattler, M; Gallinat, S; Wenck, H; Poertner, R; Fischer, F

    2012-04-01

    In dermal photodamage the ratio of the collagen types III to I changes. This makes the investigation of the fibrillar collagen type characteristics interesting for skin research. In this study collagen types were characterized using 5-dimensional multiphoton laser scanning microscopy (5D-IVT) that can be applied in vivo. Second harmonic generation (SHG) signals and fluorescence lifetimes of the collagen autofluorescence were analysed. Collagen type I generates a higher SHG intensity and a longer fluorescence lifetime compared to collagen type III. Thus, the SHG intensity decrease found in photodamaged skin might be explained by the increase in collagen type III. Calculating the in vivo relevant increase of collagen type III gives a negligible difference in fluorescence lifetime not qualifying this method for the determination of collagen type changes in dermal photodamage in vivo in human skin. However, for pathologies that exhibit higher differences in collagen types 5D-IVT analysis might be a suitable method.

  5. Protein Fibrillar Nanopolymers: Molecular-Level Insights into Their Structural, Physical and Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Trusova, Valeriya M.

    2015-09-01

    Amyloid fibrils represent a generic class of mechanically strong and stable biomaterials with extremely advantageous properties. Although amyloids were initially associated only with severe neurological disorders, the role of these structures nowadays is shifting from health debilitating to highly beneficial both in biomedical and technological aspects. Intensive involvement of fibrillar assemblies into the wide range of pathogenic and functional processes strongly necessitate the molecular level characterization of the structural, physical and elastic features of protein nanofibrils. In the present contribution, we made an attempt to highlight the up-to-date progress in the understanding of amyloid properties from the polymer physics standpoint. The fundamental insights into protein fibril behavior are essential not only for development of therapeutic strategies to combat the protein misfolding disorders but also for rational and precise design of novel biodegradable protein-based nanopolymers.

  6. Using Pittsburgh Compound B for In Vivo PET Imaging of Fibrillar Amyloid-Beta

    PubMed Central

    Cohen, Ann D.; Rabinovici, Gil D.; Mathis, Chester A.; Jagust, William J.; Klunk, William E.; Ikonomovic, Milos D.

    2012-01-01

    The development of Aβ-PET imaging agents has allowed for detection of fibrillar Aβ deposition in vivo and marks a major advancement in understanding the role of Aβ in Alzheimer’s disease (AD). Imaging Aβ thus has many potential clinical benefits: early or perhaps preclinical detection of disease and accurately distinguishing AD from dementias of other non-Aβ causes in patients presenting with mild or atypical symptoms or confounding comorbidities (in which the distinction is difficult to make clinically). From a research perspective, imaging Aβ allows us to study relationships between amyloid pathology and changes in cognition, brain structure, and function across the continuum from normal aging to mild cognitive impairment (MCI) to AD; and to monitor the effectiveness of anti-Aβ drugs and relate them to neurodegeneration and clinical symptoms. Here, we will discuss the application of one of the most broadly studied and widely used Aβ imaging agents, Pittsburgh Compound-B (PiB). PMID:22840744

  7. Conversion of non-fibrillar {beta}-sheet oligomers into amyloid fibrils in Alzheimer's disease amyloid peptide aggregation

    SciTech Connect

    Benseny-Cases, Nuria; Cocera, Mercedes; Cladera, Josep

    2007-10-05

    A{beta}(1-40) is one of the main components of the fibrils found in amyloid plaques, a hallmark of brains affected by Alzheimer's disease. It is known that prior to the formation of amyloid fibrils in which the peptide adopts a well-ordered intermolecular {beta}-sheet structure, peptide monomers associate forming low and high molecular weight oligomers. These oligomers have been previously described in electron microscopy, AFM, and exclusion chromatography studies. Their specific secondary structures however, have not yet been well established. A major problem when comparing aggregation and secondary structure determinations in concentration-dependent processes such as amyloid aggregation is the different concentration range required in each type of experiment. In the present study we used the dye Thioflavin T (ThT), Fourier-transform infrared spectroscopy, and electron microscopy in order to structurally characterize the different aggregated species which form during the A{beta}(1-40) fibril formation process. A unique sample containing 90 {mu}M peptide was used. The results show that oligomeric species which form during the lag phase of the aggregation kinetics are a mixture of unordered, helical, and intermolecular non-fibrillar {beta}-structures. The number of oligomers and the amount of non-fibrillar {beta}-structures grows throughout the lag phase and during the elongation phase these non-fibrillar {beta}-structures are transformed into fibrillar (amyloid) {beta}-structures, formed by association of high molecular weight intermediates.

  8. Conformational stability of fibrillar amyloid-beta oligomers via protofilament pair formation - a systematic computational study.

    PubMed

    Kahler, Anna; Sticht, Heinrich; Horn, Anselm H C

    2013-01-01

    Amyloid-[Formula: see text] (A[Formula: see text]) oligomers play a crucial role in Alzheimer's disease due to their neurotoxic aggregation properties. Fibrillar A[Formula: see text] oligomerization can lead to protofilaments and protofilament pairs via oligomer elongation and oligomer association, respectively. Small fibrillar oligomers adopt the protofilament topology, whereas fibrils contain at least protofilament pairs. To date, the underlying growth mechanism from oligomers to the mature fibril still remains to be elucidated. Here, we performed all-atom molecular dynamics simulations in explicit solvent on single layer-like protofilaments and fibril-like protofilament pairs of different size ranging from the tetramer to the 48-mer. We found that the initial U-shaped topology per monomer is maintained over time in all oligomers. The observed deviations of protofilaments from the starting structure increase significantly with size due to the twisting of the in-register parallel [Formula: see text]-sheets. This twist causes long protofilaments to be unstable and leads to a breakage. Protofilament pairs, which are stabilized by a hydrophobic interface, exhibit more fibril-like properties such as the overall structure and the twist angle. Thus, they can act as stable conformational templates for further fibril growth. Key properties like the twist angle, shape complementarity, and energetics show a size-dependent behavior so that small oligomers favor the protofilament topology, whereas large oligomers favor the protofilament pair topology. The region for this conformational transition is at the size of approximately twelve A[Formula: see text] monomers. From that, we propose the following growth mechanism from A[Formula: see text] oligomers to fibrils: (1) elongation of short protofilaments; (2) breakage of large protofilaments; (3) formation of short protofilament pairs; and (4) elongation of protofilament pairs.

  9. Microrheological Characterization of Collagen Systems: From Molecular Solutions to Fibrillar Gels

    PubMed Central

    Shayegan, Marjan; Forde, Nancy R.

    2013-01-01

    Collagen is the most abundant protein in the extracellular matrix (ECM), where its structural organization conveys mechanical information to cells. Using optical-tweezers-based microrheology, we investigated mechanical properties both of collagen molecules at a range of concentrations in acidic solution where fibrils cannot form and of gels of collagen fibrils formed at neutral pH, as well as the development of microscale mechanical heterogeneity during the self-assembly process. The frequency scaling of the complex shear modulus even at frequencies of ∼10 kHz was not able to resolve the flexibility of collagen molecules in acidic solution. In these solutions, molecular interactions cause significant transient elasticity, as we observed for 5 mg/ml solutions at frequencies above ∼200 Hz. We found the viscoelasticity of solutions of collagen molecules to be spatially homogeneous, in sharp contrast to the heterogeneity of self-assembled fibrillar collagen systems, whose elasticity varied by more than an order of magnitude and in power-law behavior at different locations within the sample. By probing changes in the complex shear modulus over 100-minute timescales as collagen self-assembled into fibrils, we conclude that microscale heterogeneity appears during early phases of fibrillar growth and continues to develop further during this growth phase. Experiments in which growing fibrils dislodge microspheres from an optical trap suggest that fibril growth is a force-generating process. These data contribute to understanding how heterogeneities develop during self-assembly, which in turn can help synthesis of new materials for cellular engineering. PMID:23936454

  10. Effect of biological type of cattle on the incidence of the dark, firm, and dry condition in the longissimus muscle.

    PubMed

    Shackelford, S D; Koohmaraie, M; Wheeler, T L; Cundiff, L V; Dikeman, M E

    1994-02-01

    The objectives of this experiment were to characterize longissimus muscle color, texture, and firmness for beef carcasses of diverse biological types and to determine the genetic parameters of lean color, texture, and firmness. The carcasses (n = 3,641) used in this experiment were from steers produced by mating Angus, Brahman, Braunvieh, Charolais, Chianina, Galloway, Gelbvieh, Hereford, Jersey, Limousin, Longhorn, Maine Anjou, Nellore, Piedmontese, Pinzgauer, Red Poll, Sahiwal, Salers, Shorthorn, Simmental, South Devon, and Tarentaise sires to Hereford and Angus dams. Steers were fed a corn-corn silage diet from weaning until slaughter at 356 to 575 d of age. Steers were slaughtered at commercial packing plants and longissimus muscle color, texture, and firmness were scored by trained carcass evaluators. Sire line least squares means for lean color, texture, and firmness ranged approximately one unit on a 7-point scale. Chianina crosses had darker-colored lean than all breed groups except Tarentaise and Simmental crosses (P < .05). Moreover, a higher percentage (P < .05) of Chianina crosses than of all other breed groups had unacceptably dark-colored ("dark red" or darker) lean. Bos indicus sire lines were not different from Bos taurus sire lines in frequency of carcasses with unacceptably dark-colored lean. However, Bos indicus crosses were more likely to be scored "very light cherry-red." Lean color and texture were lowly heritable, whereas lean firmness was moderately heritable. Thus, this experiment demonstrated that there is genetic variation in the incidence of the DFD condition; however, genetic variation was small relative to environmental variation. PMID:8157518

  11. Effect of biological type of cattle on the incidence of the dark, firm, and dry condition in the longissimus muscle.

    PubMed

    Shackelford, S D; Koohmaraie, M; Wheeler, T L; Cundiff, L V; Dikeman, M E

    1994-02-01

    The objectives of this experiment were to characterize longissimus muscle color, texture, and firmness for beef carcasses of diverse biological types and to determine the genetic parameters of lean color, texture, and firmness. The carcasses (n = 3,641) used in this experiment were from steers produced by mating Angus, Brahman, Braunvieh, Charolais, Chianina, Galloway, Gelbvieh, Hereford, Jersey, Limousin, Longhorn, Maine Anjou, Nellore, Piedmontese, Pinzgauer, Red Poll, Sahiwal, Salers, Shorthorn, Simmental, South Devon, and Tarentaise sires to Hereford and Angus dams. Steers were fed a corn-corn silage diet from weaning until slaughter at 356 to 575 d of age. Steers were slaughtered at commercial packing plants and longissimus muscle color, texture, and firmness were scored by trained carcass evaluators. Sire line least squares means for lean color, texture, and firmness ranged approximately one unit on a 7-point scale. Chianina crosses had darker-colored lean than all breed groups except Tarentaise and Simmental crosses (P < .05). Moreover, a higher percentage (P < .05) of Chianina crosses than of all other breed groups had unacceptably dark-colored ("dark red" or darker) lean. Bos indicus sire lines were not different from Bos taurus sire lines in frequency of carcasses with unacceptably dark-colored lean. However, Bos indicus crosses were more likely to be scored "very light cherry-red." Lean color and texture were lowly heritable, whereas lean firmness was moderately heritable. Thus, this experiment demonstrated that there is genetic variation in the incidence of the DFD condition; however, genetic variation was small relative to environmental variation.

  12. Role of the von Hippel-Lindau tumor suppressor gene in the formation of beta1-integrin fibrillar adhesions.

    PubMed

    Esteban-Barragán, Miguel A; Avila, Pilar; Alvarez-Tejado, Miguel; Gutiérrez, M Dolores; García-Pardo, Angeles; Sánchez-Madrid, Francisco; Landázuri, Manuel O

    2002-05-15

    The von Hippel-Lindau tumor suppressor gene (VHL) is absent or inactivated in the VHLcancer syndrome and in most sporadic renal cancers. VHL is requiredfor the assembly of a proper extracellular fibronectin matrix, although the exact mechanism remains unknown. In this report, we demonstrate that 786-O renal cancer cells are unable to organize an adequate matrix even in the presence of an excess of exogenous fibronectin. Because the formation of integrin fibrillar adhesions plays a pivotal role in the organization of extracellular fibronectin, we next examined the expression and subcellular distribution of integrins in VHL- cells and their wild-type VHL stably transfected counterparts. The levels of beta1 and alphav integrins were increased in VHL- cells when compared with VHL+ transfectants. Early after plating, both VHL+ and VHL- cells were capable of assembling classic "patch-like" alphav focal contacts. As the culture advanced and cells became confluent, alphav integrins partly relocated to the intercellular junctions in VHL+ transfectants, which then developed large beta1 fibrillar-type adhesions and anchored firmly to the substrate. In contrast, confluent VHL- cells were unable to assemble beta1 fibrillar adhesions, and alphav focal contacts remained unchanged at all stages of the culture. Exogenous activation of beta1 integrins with either divalent cations or activating antibodies partly restored the capability of VHL- cells to assemble beta1 fibrillar adhesions and fibronectin fibers. Finally, pulse-chase studies of metabolically labeled 786-O cells revealed that the maturation of the common beta1-integrin chain was delayed in VHL- cells when compared with VHL+ cells. Our results show that VHL is an important regulator of integrins and is essential for the formation of beta1 fibrillar adhesions. These findings help to explain the abnormal extracellular matrix organization and increased motility of VHL- renal cancer cells. PMID:12019174

  13. Dry hair

    MedlinePlus

    Some causes of dry hair are: Anorexia nervosa Excessive hair washing, or using harsh soaps or alcohols Excessive blow-drying Dry air Menkes kinky hair syndrome Malnutrition Underactive parathyroid ( ...

  14. The process of EDC-NHS Cross-linking of reconstituted collagen fibres increases collagen fibrillar order and alignment

    PubMed Central

    Shepherd, D.V.; Shepherd, J.H.; Ghose, S.; Kew, S.J.; Cameron, R.E.; Best, S.M.

    2014-01-01

    We describe the production of collagen fibre bundles through a multi-strand, semi-continuous extrusion process. Cross-linking using an EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide), NHS (N-hydroxysuccinimide) combination was considered. Atomic Force Microscopy (AFM) and Raman spectroscopy focused on how cross-linking affected the collagen fibrillar structure. In the cross-linked fibres, a clear fibrillar structure comparable to native collagen was observed which was not observed in the non-cross-linked fibre. The amide III doublet in the Raman spectra provided additional evidence of alignment in the cross-linked fibres. Raman spectroscopy also indicated no residual polyethylene glycol (from the fibre forming buffer) or water in any of the fibres. PMID:25506518

  15. The process of EDC-NHS cross-linking of reconstituted collagen fibres increases collagen fibrillar order and alignment

    SciTech Connect

    Shepherd, D. V. Shepherd, J. H.; Cameron, R. E.; Best, S. M.; Ghose, S.; Kew, S. J.

    2015-01-01

    We describe the production of collagen fibre bundles through a multi-strand, semi-continuous extrusion process. Cross-linking using an EDC (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide), NHS (N-hydroxysuccinimide) combination was considered. Atomic Force Microscopy and Raman spectroscopy focused on how cross-linking affected the collagen fibrillar structure. In the cross-linked fibres, a clear fibrillar structure comparable to native collagen was observed which was not observed in the non-cross-linked fibre. The amide III doublet in the Raman spectra provided additional evidence of alignment in the cross-linked fibres. Raman spectroscopy also indicated no residual polyethylene glycol (from the fibre forming buffer) or water in any of the fibres.

  16. Hierarchical macroscopic fibrillar adhesives: in situ study of buckling and adhesion mechanisms on wavy substrates.

    PubMed

    Bauer, Christina T; Kroner, Elmar; Fleck, Norman A; Arzt, Eduard

    2015-10-23

    Nature uses hierarchical fibrillar structures to mediate temporary adhesion to arbitrary substrates. Such structures provide high compliance such that the flat fibril tips can be better positioned with respect to asperities of a wavy rough substrate. We investigated the buckling and adhesion of hierarchically structured adhesives in contact with flat smooth, flat rough and wavy rough substrates. A macroscopic model for the structural adhesive was fabricated by molding polydimethylsiloxane into pillars of diameter in the range of 0.3-4.8 mm, with up to three different hierarchy levels. Both flat-ended and mushroom-shaped hierarchical samples buckled at preloads one quarter that of the single level structures. We explain this behavior by a change in the buckling mode; buckling leads to a loss of contact and diminishes adhesion. Our results indicate that hierarchical structures can have a strong influence on the degree of adhesion on both flat and wavy substrates. Strategies are discussed that achieve highly compliant substrates which adhere to rough substrates.

  17. Differential Relationships of Reactive Astrocytes and Microglia to Fibrillar Amyloid Deposits in Alzheimer Disease

    PubMed Central

    Serrano-Pozo, Alberto; Muzikansky, Alona; Gómez-Isla, Teresa; Growdon, John H.; Betensky, Rebecca A.; Frosch, Matthew P.; Hyman, Bradley T.

    2013-01-01

    While it is clear that astrocytes and microglia cluster around dense-core amyloid plaques in Alzheimer disease (AD), whether they are primarily attracted to amyloid deposits or are just reacting to plaque-associated neuritic damage remains elusive. We postulate that astrocytes and microglia may differentially respond to fibrillar amyloid β (Aβ). Therefore, we quantified the size distribution of dense-core Thioflavin-S (ThioS)-positive plaques in the temporal neocortex of 40 AD patients and the microglial and astrocyte responses in their vicinity (≤50 μm), and performed correlations between both measures. As expected, both astrocytes and microglia were clearly spatially associated with ThioS-positive plaques (p = 0.0001, ≤50 μm vs. >50 μm from their edge), but their relationship to ThioS-positive plaque size differed; larger ThioS-positive plaques were associated with more surrounding activated microglia (p = 0.0026), but this effect was not observed with reactive astrocytes. Microglial response to dense-core plaques appears to be proportional to their size, which we postulate reflects a chemotactic effect of Aβ. By contrast, plaque-associated astrocytic response does not correlate with plaque size and seems to parallel the behavior of plaque-associated neuritic damage. PMID:23656989

  18. Monoclonal Antibodies Inhibit in vitro Fibrillar Aggregation of the Alzheimer β -Amyloid Peptide

    NASA Astrophysics Data System (ADS)

    Solomon, Beka; Koppel, Rela; Hanan, Eilat; Katzav, Tamar

    1996-01-01

    The β -amyloid peptide, the hallmark of Alzheimer disease, forms fibrillar toxic aggregates in brain tissue that can be dissolved only by strong denaturing agents. To study β -amyloid formation and its inhibition, we prepared immune complexes with two monoclonal antibodies (mAbs), AMY-33 and 6F/3D, raised against β -amyloid fragments spanning amino acid residues 1-28 and 8-17 of the β -amyloid peptide chain, respectively. In vitro aggregation of β -amyloid peptide was induced by incubation for 3 h at 37 degrees C and monitored by ELISA, negative staining electron microscopy, and fluorimetric studies. We found that the mAbs prevent the aggregation of β -amyloid peptide and that the inhibitory effect appears to be related to the localization of the antibody-binding sites and the nature of the aggregating agents. Preparation of mAbs against ``aggregating epitopes,'' defined as sequences related to the sites where protein aggregation is initiated, may lead to the understanding and prevention of protein aggregation. The results of this study may provide a foundation for using mAbs in vivo to prevent the β -amyloid peptide aggregation that is associated with Alzheimer disease.

  19. The fibrillar structure of the cemento-dentinal junction in different kinds of human teeth.

    PubMed

    Yamamoto, T; Domon, T; Takahashi, S; Islam, M N; Suzuki, R

    2001-10-01

    The cemento-dentinal junction was examined in human maxillary incisors, canines and premolars by scanning electron microscopy combined with NaOH maceration. The NaOH maceration was used to remove interfibrillar substances and to observe details of the fibrillar architecture. The teeth were half-sectioned longitudinally, demineralized and macerated for 3-4 days or for 10-14 days. In the 3-4 day-macerated specimens, longitudinal sections of the cemento-dentinal junction were examined. In the 10-14 day-macerated specimens, the cementum was detached and the inner cementum surface facing the cemento-dentinal junction was examined. Observations suggested that cemental fibrils intermingle with dentinal fibrils only in places at the cemento-dentinal junction in both acellular and cellular cementum. These structural features were consistent in all kinds of teeth investigated here. Using human molars, we have previously proposed that the adhesion of proteoglycans is a main factor for the cemento-dentinal attachment and that the fibril intermingling between dentin and cementum is an accessory or secondary factor. The present study suggests that this applies to other kinds of human teeth. PMID:11585119

  20. Instantly switchable adhesion of bridged fibrillar adhesive via gecko-inspired detachment mechanism and its application to a transportation system.

    PubMed

    Bae, Won-Gyu; Kim, Doogon; Suh, Kahp-Yang

    2013-12-01

    Inspired by the exceptional climbing ability of gecko lizards, artificial fibrillar adhesives have been extensively studied over the last decade both experimentally and theoretically. Therefore, a new leap towards practical uses beyond the academic horizon is timely and highly anticipated. To this end, we present a fibrillar adhesive in the form of bridged micropillars and its application to a transportation system with the detachment mechanism inspired by the climbing behaviour of gecko lizards. The adhesive shows strong normal attachment (~30 N cm(-2)) as well as easy and fast detachment within 0.5 s without involving complex dynamic mechanisms or specific stimulus-responsive materials. The fabrication of the bridged micropillars consists of replica moulding of polydimethylsiloxane (PDMS) micropillars, transfer of the PDMS precursor to the heads of the micropillars, and inverse placement on an inert Teflon-coated surface. Owing to the spontaneous interconnections of low viscosity PDMS precursor, bridged micropillars with a uniform capping nanomembrane (~800 nm thickness) are formed over a large area. Interestingly, macroscopic adhesion in the normal direction can be immediately switched between on and off states by changing the two detachment modes of pulling and peeling, respectively. To prove the potential of the fibrillar adhesive for practical use, an automated transportation system is demonstrated for lifting and releasing a mass of stacked glass slides over 1000 cycles of attachment and detachment.

  1. Simultaneous determination of inorganic mercury, methylmercury, and total mercury concentrations in cryogenic fresh-frozen and freeze-dried biological reference materials.

    PubMed

    Point, David; Davis, W Clay; Garcia Alonso, J Ignacio; Monperrus, Mathilde; Christopher, Steven J; Donard, Olivier F X; Becker, Paul R; Wise, Stephen A

    2007-10-01

    Two speciated isotope dilution (SID) approaches consisting of a single-spike (SS) method and a double-spike (DS) method including a reaction/transformation model for the correction of inadvertent transformations affecting mercury species were compared in terms of accuracy, method performance, and robustness for the simultaneous determination of methylmercury (MeHg), inorganic mercury (iHg), and total mercury (HgT) concentrations in five biological Standard Reference Materials (SRMs). The SRMs consisted of oyster and mussel tissue materials displaying different mercury species concentration levels and different textural/matrix properties including freeze-dried (FD) materials (SRMs 1566b, 2976, and 2977) and cryogenically prepared and stored fresh-frozen (FF) materials (SRMs 1974a, 1974b). Each sample was spiked with (201)iHg (Oak Ridge National Laboratory, ORNL) and Me(202)Hg (Institute for Reference Materials and Measurements. IRMM-670) solutions and analyzed using alkaline microwave digestion, ethylation, and gas chromatography inductively coupled plasma mass spectrometry (GC/ICP-MS). The results obtained by the SS-SID method suggested that FF and FD materials are not always commutable for the simultaneous determination of iHg, MeHg, and HgT, due to potential transformation reactions resulting probably from the methodology and/or from the textural/matrix properties of the materials. These transformations can occasionally significantly affect mercury species concentration results obtained by SS-SID, depending on the species investigated and the materials considered. The results obtained by the DS-SID method indicated that the two classes of materials were commutable. The simultaneous and corrected concentrations of iHg, MeHg, and HgT obtained by this technique were not found to be statistically different form the certified and reference concentration together with their expanded uncertainty budgets for the five SRMs investigated, exemplifying the robustness, the

  2. An integrated view on how the management of the dry period length of lactating cows could affect mammary biology and defence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dry period is necessary to facilitate cell turnover in the bovine mammary gland and to optimize milk production in the next lactation. An eight-week dry period has long been the golden standard of management for dairy cows. Genetic improvements and new management technologies have led to higher ...

  3. Sources of variability in platelet accumulation on type 1 fibrillar collagen in microfluidic flow assays.

    PubMed

    Neeves, Keith B; Onasoga, Abimbola A; Hansen, Ryan R; Lilly, Jessica J; Venckunaite, Diana; Sumner, Meghan B; Irish, Andrew T; Brodsky, Gary; Manco-Johnson, Marilyn J; Di Paola, Jorge A

    2013-01-01

    Microfluidic flow assays (MFA) that measure shear dependent platelet function have potential clinical applications in the diagnosis and treatment of bleeding and thrombotic disorders. As a step towards clinical application, the objective of this study was to measure how phenotypic and genetic factors, as well as experimental conditions, affect the variability of platelet accumulation on type 1 collagen within a MFA. Whole blood was perfused over type 1 fibrillar collagen at wall shear rates of 150, 300, 750 and 1500 s⁻¹ through four independent channels with a height of 50 µm and a width of 500 µm. The accumulation of platelets was characterized by the lag time to 1% platelet surface coverage (Lag(T)), the rate of platelet accumulation (V(PLT)), and platelet surface coverage (SC). A cohort of normal donors was tested and the results were correlated to plasma von Willebrand factor (VWF) levels, platelet count, hematocrit, sex, and collagen receptors genotypes. VWF levels were the strongest determinant of platelet accumulation. VWF levels were positively correlated to V(PLT) and SC at all wall shear rates. A longer Lag(T) for platelet accumulation at arterial shear rates compared to venous shear rates was attributed to the time required for plasma proteins to adsorb to collagen. There was no association between platelet accumulation and hematocrit or platelet count. Individuals with the AG genotype of the GP6 gene had lower platelet accumulation than individuals with the AA genotype at 150 s⁻¹ and 300 s⁻¹. Recalcified blood collected into sodium citrate and corn trypsin inhibitor (CTI) resulted in diminished platelet accumulation compared to CTI alone, suggesting that citrate irreversibly diminishes platelet function. This study the largest association study of MFA in healthy donors (n = 104) and will likely set up the basis for the determination of the normal range of platelet responses in this type of assay. PMID:23355889

  4. Sources of Variability in Platelet Accumulation on Type 1 Fibrillar Collagen in Microfluidic Flow Assays

    PubMed Central

    Neeves, Keith B.; Onasoga, Abimbola A.; Hansen, Ryan R.; Lilly, Jessica J.; Venckunaite, Diana; Sumner, Meghan B.; Irish, Andrew T.; Brodsky, Gary; Manco-Johnson, Marilyn J.; Di Paola, Jorge A.

    2013-01-01

    Microfluidic flow assays (MFA) that measure shear dependent platelet function have potential clinical applications in the diagnosis and treatment of bleeding and thrombotic disorders. As a step towards clinical application, the objective of this study was to measure how phenotypic and genetic factors, as well as experimental conditions, affect the variability of platelet accumulation on type 1 collagen within a MFA. Whole blood was perfused over type 1 fibrillar collagen at wall shear rates of 150, 300, 750 and 1500 s−1 through four independent channels with a height of 50 µm and a width of 500 µm. The accumulation of platelets was characterized by the lag time to 1% platelet surface coverage (LagT), the rate of platelet accumulation (VPLT), and platelet surface coverage (SC). A cohort of normal donors was tested and the results were correlated to plasma von Willebrand factor (VWF) levels, platelet count, hematocrit, sex, and collagen receptors genotypes. VWF levels were the strongest determinant of platelet accumulation. VWF levels were positively correlated to VPLT and SC at all wall shear rates. A longer LagT for platelet accumulation at arterial shear rates compared to venous shear rates was attributed to the time required for plasma proteins to adsorb to collagen. There was no association between platelet accumulation and hematocrit or platelet count. Individuals with the AG genotype of the GP6 gene had lower platelet accumulation than individuals with the AA genotype at 150 s−1 and 300 s−1. Recalcified blood collected into sodium citrate and corn trypsin inhibitor (CTI) resulted in diminished platelet accumulation compared to CTI alone, suggesting that citrate irreversibly diminishes platelet function. This study the largest association study of MFA in healthy donors (n = 104) and will likely set up the basis for the determination of the normal range of platelet responses in this type of assay. PMID:23355889

  5. Dry Mouth

    MedlinePlus

    Dry mouth is the feeling that there is not enough saliva in your mouth. Everyone has a dry mouth once in a while - if they are nervous, ... under stress. But if you have a dry mouth all or most of the time, it can ...

  6. Instantly switchable adhesion of bridged fibrillar adhesive via gecko-inspired detachment mechanism and its application to a transportation system

    NASA Astrophysics Data System (ADS)

    Bae, Won-Gyu; Kim, Doogon; Suh, Kahp-Yang

    2013-11-01

    Inspired by the exceptional climbing ability of gecko lizards, artificial fibrillar adhesives have been extensively studied over the last decade both experimentally and theoretically. Therefore, a new leap towards practical uses beyond the academic horizon is timely and highly anticipated. To this end, we present a fibrillar adhesive in the form of bridged micropillars and its application to a transportation system with the detachment mechanism inspired by the climbing behaviour of gecko lizards. The adhesive shows strong normal attachment (~30 N cm-2) as well as easy and fast detachment within 0.5 s without involving complex dynamic mechanisms or specific stimulus-responsive materials. The fabrication of the bridged micropillars consists of replica moulding of polydimethylsiloxane (PDMS) micropillars, transfer of the PDMS precursor to the heads of the micropillars, and inverse placement on an inert Teflon-coated surface. Owing to the spontaneous interconnections of low viscosity PDMS precursor, bridged micropillars with a uniform capping nanomembrane (~800 nm thickness) are formed over a large area. Interestingly, macroscopic adhesion in the normal direction can be immediately switched between on and off states by changing the two detachment modes of pulling and peeling, respectively. To prove the potential of the fibrillar adhesive for practical use, an automated transportation system is demonstrated for lifting and releasing a mass of stacked glass slides over 1000 cycles of attachment and detachment.Inspired by the exceptional climbing ability of gecko lizards, artificial fibrillar adhesives have been extensively studied over the last decade both experimentally and theoretically. Therefore, a new leap towards practical uses beyond the academic horizon is timely and highly anticipated. To this end, we present a fibrillar adhesive in the form of bridged micropillars and its application to a transportation system with the detachment mechanism inspired by the

  7. Increased fibrillar amyloid-{beta} burden in normal individuals with a family history of late-onset Alzheimer's.

    PubMed

    Mosconi, Lisa; Rinne, Juha O; Tsui, Wai H; Berti, Valentina; Li, Yi; Wang, Huiyu; Murray, John; Scheinin, Noora; Någren, Kjell; Williams, Schantel; Glodzik, Lidia; De Santi, Susan; Vallabhajosula, Shankar; de Leon, Mony J

    2010-03-30

    Having a parent affected with late-onset Alzheimer's disease (LOAD) is a major risk factor among cognitively normal (NL) individuals. This (11)C-Pittsburgh Compound B (PiB)-PET study examines whether NL individuals with LOAD parents show increased fibrillar amyloid-beta (Abeta) deposition, a hallmark of Alzheimer's disease (AD) pathology and whether there are parent-of-origin effects. Forty-two 50- to 80-year-old NL persons were examined with PiB-PET. These individuals included 14 NL subjects with a maternal family history (FH) of LOAD (FHm), 14 NL subjects with a paternal FH (FHp), and 14 NL subjects with a negative family history of any dementia (FH-). Statistical parametric mapping and automated regions-of-interest were used to compare cerebral-to-cerebellar PiB standardized uptake value ratios, reflecting fibrillar Abeta burden, across groups. FH groups did not differ in age, gender, education, and apolipoprotein E (ApoE) status. NL FHm subjects showed higher PiB retention in AD-affected anterior and posterior cingulate cortex (PCC), precuneus, parietal, temporal, occipital, and frontal cortices, right basal ganglia, and thalamus, compared with FH- and FHp subjects. FHp subjects showed increased PiB retention in the PCC and frontal cortex, intermediate between FHm and FH- subjects. Results remained significant after controlling for age, gender, education, and ApoE status. Children of parents with LOAD, particularly those with affected mothers, have increased fibrillar Abeta load in AD-vulnerable regions compared with controls, perhaps accounting for the known increased risk for AD. Present findings may motivate further research on familial transmission and parent-of-origin effects in LOAD.

  8. Increased fibrillar amyloid-β burden in normal individuals with a family history of late-onset Alzheimer’s

    PubMed Central

    Mosconi, Lisa; Rinne, Juha O.; Tsui, Wai H.; Berti, Valentina; Li, Yi; Wang, Huiyu; Murray, John; Scheinin, Noora; Någren, Kjell; Williams, Schantel; Glodzik, Lidia; De Santi, Susan; Vallabhajosula, Shankar; de Leon, Mony J.

    2010-01-01

    Having a parent affected with late-onset Alzheimer's disease (LOAD) is a major risk factor among cognitively normal (NL) individuals. This 11C-Pittsburgh Compound B (PiB)-PET study examines whether NL individuals with LOAD parents show increased fibrillar amyloid-beta (Aβ) deposition, a hallmark of Alzheimer's disease (AD) pathology and whether there are parent-of-origin effects. Forty-two 50- to 80-year-old NL persons were examined with PiB-PET. These individuals included 14 NL subjects with a maternal family history (FH) of LOAD (FHm), 14 NL subjects with a paternal FH (FHp), and 14 NL subjects with a negative family history of any dementia (FH−). Statistical parametric mapping and automated regions-of-interest were used to compare cerebral-to-cerebellar PiB standardized uptake value ratios, reflecting fibrillar Aβ burden, across groups. FH groups did not differ in age, gender, education, and apolipoprotein E (ApoE) status. NL FHm subjects showed higher PiB retention in AD-affected anterior and posterior cingulate cortex (PCC), precuneus, parietal, temporal, occipital, and frontal cortices, right basal ganglia, and thalamus, compared with FH− and FHp subjects. FHp subjects showed increased PiB retention in the PCC and frontal cortex, intermediate between FHm and FH− subjects. Results remained significant after controlling for age, gender, education, and ApoE status. Children of parents with LOAD, particularly those with affected mothers, have increased fibrillar Aβ load in AD-vulnerable regions compared with controls, perhaps accounting for the known increased risk for AD. Present findings may motivate further research on familial transmission and parent-of-origin effects in LOAD. PMID:20231448

  9. Zinc-Amyloid Interactions on a Millisecond Time-Scale Stabilize Non-Fibrillar Alzheimer Related Species

    SciTech Connect

    Noy,D.; Solomonov, I.; Sinkevich, O.; Arad, A.; Kjaer, K.; Sagi, I.

    2008-01-01

    The role of zinc, an essential element for normal brain function, in the pathology of Alzheimer's disease (AD) is poorly understood. On one hand, physiological and genetic evidence from transgenic mouse models supports its pathogenic role in promoting the deposition of the amyloid {beta}-protein (A{beta}) in senile plaques. On the other hand, levels of extracellular ('free') zinc in the brain, as inferred by the levels of zinc in cerebrospinal fluid, were found to be too low for inducing A{beta} aggregation. Remarkably, the release of transient high local concentrations of zinc during rapid synaptic events was reported. The role of such free zinc pulses in promoting A{beta} aggregation has never been established. Using a range of time-resolved structural and spectroscopic techniques, we found that zinc, when introduced in millisecond pulses of micromolar concentrations, immediately interacts with A{beta} 1-40 and promotes its aggregation. These interactions specifically stabilize non-fibrillar pathogenic related aggregate forms and prevent the formation of A{beta} fibrils (more benign species) presumably by interfering with the self-assembly process of A{beta}. These in vitro results strongly suggest a significant role for zinc pulses in A{beta} pathology. We further propose that by interfering with A{beta} self-assembly, which leads to insoluble, non-pathological fibrillar forms, zinc stabilizes transient, harmful amyloid forms. This report argues that zinc represents a class of molecular pathogens that effectively perturb the self-assembly of benign A{beta} fibrils, and stabilize harmful non-fibrillar forms.

  10. The new evidence of nucleolar ultrastructural dynamic change: fibrillar centre (FC) fusion in G1 phase and regeneration in S phase.

    PubMed

    Wang, Fengcai; Ying, Chen; Shang, Guangbin; Jiao, Mingda; Hongfang, Zhang

    2013-06-01

    In higher eukaryotes ribosome production starts at the end of mitosis, increases during G1, is maximal in G2 (Sirri et al., 2000) and stops during prophase (Gébrane-Younès et al., 1997). But the mechanism of the change is still uncovered. Especially in the actively growing mammalian somatic cells usually contain one or several giant fibrillar centres (GFCs) with many tiny fibrillar centre (FCs) (Koberna et al., 2002; Raška et al., 2004; Casafont et al., 2007). The process how the giant fibrillar centre (GFC) and the many tiny fibrillar centres (FCs) were formed is unknown. The present results showed there were processes of FCs fusion in G1 phase and FCs regeneration in S phase respectively in the nucleoli of A 375 cells. A few FCs fused each other in late G1 phase when the process of nucleoli fusion was completed. In S phase, a lot of tiny FCs were regenerated from the periphery of GFC, separated and scattered into nucleolar matrix in late S phase and early G2 phase. The GFC was found to be coexisted with numerous tiny FCs in the nucleolus in G2 phase. The present study provided a new evidence of nucleolar dynamic change during interphase: fibrillar centre (FC) was not to be a stable state subunit of nucleolar compartment but a highly dynamic process that may be the bases of nucleolar morphological architecture organization and its function taking place. PMID:23602556

  11. Design of gecko-inspired fibrillar surfaces with strong attachment and easy-removal properties: a numerical analysis of peel-zone.

    PubMed

    Zhou, Ming; Pesika, Noshir; Zeng, Hongbo; Wan, Jin; Zhang, Xiangjun; Meng, Yonggang; Wen, Shizhu; Tian, Yu

    2012-10-01

    Despite successful fabrication of gecko-inspired fibrillar surfaces with strong adhesion forces, how to achieve an easy-removal property becomes a major concern that may restrict the wide applications of these bio-inspired surfaces. Research on how geckos detach rapidly has inspired the design of novel adhesive surfaces with strong and reversible adhesion capabilities, which relies on further fundamental understanding of the peeling mechanisms. Recent studies showed that the peel-zone plays an important role in the peeling off of adhesive tapes or fibrillar surfaces. In this study, a numerical method was developed to evaluate peel-zone deformation and the resulting mechanical behaviour due to the deformations of fibrillar surfaces detaching from a smooth rigid substrate. The effect of the geometrical parameters of pillars and the stiffness of backing layer on the peel-zone and peel strength, and the strong attachment and easy-removal properties have been analysed to establish a design map for bio-inspired fibrillar surfaces, which shows that the optimized strong attachment and easy-removal properties can vary by over three orders of magnitude. The adhesion and peeling design map established provides new insights into the design and development of novel gecko-inspired fibrillar surfaces.

  12. Salt drying: a low-cost, simple and efficient method for storing plants in the field and preserving biological repositories for DNA diversity research.

    PubMed

    Carrió, Elena; Rosselló, Josep A

    2014-03-01

    Although a variety of methods have been optimized for the collection and storage of plant specimens, most of these are not suited for field expeditions for a variety of logistic reasons. Drying specimens with silica gel in polyethylene bags is currently the standard for field-sampling methods that are suitable for subsequent DNA extraction. However, silica-gel repositories are not readily available in remote areas, and its use is not very cost-effective for the long-term storage of collections or in developing countries with limited research budgets. Salting is an ancient and traditional drying process that preserves food samples by dehydrating tissues and inhibiting water-dependent cellular metabolism. We compared salt and silica-gel drying methods with respect to dehydration rates overtime, DNA quality and polymerase chain reaction(PCR) success to assess whether dry salting can be used as an effective plant preservation method for DNA analysis. Specimens from eleven plant species covering a variety of leaf structures, leaf thicknesses and water contents were analysed. Experimental work indicated that (i) levels of dehydration in sodium chloride were usually comparable to those obtained when silica gel was used, (ii) no spoilage, fungal or bacterial growth was observed for any of the species with all drying treatments and (iii) good yields of quality genomic DNA suitable for PCR applications were obtained in the salt-drying treatments. The preservation of plant tissues in commercial table salt appears to be a satisfactory, and versatile method that may be suitable in remote areas where cryogenic resources and silica repositories are not available.

  13. Co-fibrillogenesis of Wild-type and D76N β2-Microglobulin: THE CRUCIAL ROLE OF FIBRILLAR SEEDS.

    PubMed

    Natalello, Antonino; Mangione, P Patrizia; Giorgetti, Sofia; Porcari, Riccardo; Marchese, Loredana; Zorzoli, Irene; Relini, Annalisa; Ami, Diletta; Faravelli, Giulia; Valli, Maurizia; Stoppini, Monica; Doglia, Silvia M; Bellotti, Vittorio; Raimondi, Sara

    2016-04-29

    The amyloidogenic variant of β2-microglobulin, D76N, can readily convert into genuine fibrils under physiological conditions and primes in vitro the fibrillogenesis of the wild-type β2-microglobulin. By Fourier transformed infrared spectroscopy, we have demonstrated that the amyloid transformation of wild-type β2-microglobulin can be induced by the variant only after its complete fibrillar conversion. Our current findings are consistent with preliminary data in which we have shown a seeding effect of fibrils formed from D76N or the natural truncated form of β2-microglobulin lacking the first six N-terminal residues. Interestingly, the hybrid wild-type/variant fibrillar material acquired a thermodynamic stability similar to that of homogenous D76N β2-microglobulin fibrils and significantly higher than the wild-type homogeneous fibrils prepared at neutral pH in the presence of 20% trifluoroethanol. These results suggest that the surface of D76N β2-microglobulin fibrils can favor the transition of the wild-type protein into an amyloid conformation leading to a rapid integration into fibrils. The chaperone crystallin, which is a mild modulator of the lag phase of the variant fibrillogenesis, potently inhibits fibril elongation of the wild-type even once it is absorbed on D76N β2-microglobulin fibrils. PMID:26921323

  14. Elongated fibrillar structure of a streptococcal adhesin assembled by the high-affinity association of [alpha]- and PPII-helices

    SciTech Connect

    Larson, Matthew R.; Rajashankar, Kanagalaghatta R.; Patel, Manisha H.; Robinette, Rebekah A.; Crowley, Paula J.; Michalek, Suzanne; Brady, L. Jeannine; Deivanayagam, Champion

    2010-08-18

    Streptococcus mutans antigen I/II (AgI/II) is a cell surface-localized protein adhesin that interacts with salivary components within the salivary pellicle. AgI/II contributes to virulence and has been studied as an immunological and structural target, but a fundamental understanding of its underlying architecture has been lacking. Here we report a high-resolution (1.8 {angstrom}) crystal structure of the A{sub 3}VP{sub 1} fragment of S. mutans AgI/II that demonstrates a unique fibrillar form (155 {angstrom}) through the interaction of two noncontiguous regions in the primary sequence. The A{sub 3} repeat of the alanine-rich domain adopts an extended {alpha}-helix that intertwines with the P{sub 1} repeat polyproline type II (PPII) helix to form a highly extended stalk-like structure heretofore unseen in prokaryotic or eukaryotic protein structures. Velocity sedimentation studies indicate that full-length AgI/II that contains three A/P repeats extends over 50 nanometers in length. Isothermal titration calorimetry revealed that the high-affinity association between the A{sub 3} and P{sub 1} helices is enthalpically driven. Two distinct binding sites on AgI/II to the host receptor salivary agglutinin (SAG) were identified by surface plasmon resonance (SPR). The current crystal structure reveals that AgI/II family proteins are extended fibrillar structures with the number of alanine- and proline-rich repeats determining their length.

  15. Endothelial Cell Culture on Fibrillar Collagen: Model to Study Platelet Adhesion and Liposome Targeting to Intercellular Collagen Matrix

    NASA Astrophysics Data System (ADS)

    Chazov, E. I.; Alexeev, A. V.; Antonov, A. S.; Koteliansky, V. E.; Leytin, V. L.; Lyubimova, E. V.; Repin, V. S.; Sviridov, D. D.; Torchilin, V. P.; Smirnov, V. N.

    1981-09-01

    Human umbilical endothelial cells (ECs) were grown on fibrillar type I collagen in 16.4-mm multiwell tissue culture plates. Human platelets were added to the wells, and platelet adhesion to collagen was examined by scanning electron microscopy and radioisotopic technique in the absence of ECs and in preconfluent and confluent EC cultures. Single adherent platelets of different shapes as well as small aggregates were seen on collagen surface. Human plasma fibronectin added to the system stimulated platelet adhesion and their spreading on collagen. ECs had no effect on the percentage of platelets adherent to collagen-coated gaps in preconfluent culture but decreased the number of spread platelets. It is demonstrated that collagen-coated gaps can bind 14C-labeled liposome-antibody and 14C-labeled liposome-fibronectin conjugates. ECs grown on fibrillar collagen are suggested as useful models for screening of antiplatelet drugs and for the study of drug targeting to the areas of vascular injury for prevention of thrombosis.

  16. Catalytically active telomerase holoenzyme is assembled in the dense fibrillar component of the nucleolus during S phase.

    PubMed

    Lee, Ji Hoon; Lee, Yang Sin; Jeong, Sun Ah; Khadka, Prabhat; Roth, Jürgen; Chung, In Kwon

    2014-02-01

    The maintenance of human telomeres requires the ribonucleoprotein enzyme telomerase, which is composed of telomerase reverse transcriptase (TERT), telomerase RNA component, and several additional proteins for assembly and activity. Telomere elongation by telomerase in human cancer cells involves multiple steps including telomerase RNA biogenesis, holoenzyme assembly, intranuclear trafficking, and telomerase recruitment to telomeres. Although telomerase has been shown to accumulate in Cajal bodies for association with telomeric chromatin, it is unclear where and how the assembly and trafficking of catalytically active telomerase is regulated in the context of nuclear architecture. Here, we show that the catalytically active holoenzyme is initially assembled in the dense fibrillar component of the nucleolus during S phase. The telomerase RNP is retained in nucleoli through the interaction of hTERT with nucleolin, a major nucleolar phosphoprotein. Upon association with TCAB1 in S phase, the telomerase RNP is transported from nucleoli to Cajal bodies, suggesting that TCAB1 acts as an S-phase-specific holoenzyme component. Furthermore, depletion of TCAB1 caused an increase in the amount of telomerase RNP associated with nucleolin. These results suggest that the TCAB1-dependent trafficking of telomerase to Cajal bodies occurs in a step separate from the holoenzyme assembly in nucleoli. Thus, we propose that the dense fibrillar component is the provider of active telomerase RNP for supporting the continued proliferation of cancer and stem cells.

  17. Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained

    PubMed Central

    HAUGAN, E; HOLST, B

    2013-01-01

    The identification of bast fibre samples, in particular, bast fibres used in textiles, is an important issue in archaeology, criminology and other scientific fields. One of the characteristic features of bast fibres is their fibrillar orientation, referred to as Z- or S twist (or alternatively right- and left-handed fibres). An empirical test for determining the fibrillar orientation using polarized light microscopy has been known in the community for many years. It is referred to as the modified Herzog test or red plate test. The test has the reputation for never producing false results, but also for occasionally not working. However, so far, no proper justification has been provided in the literature that the ‘no false results’ assumption is really correct and it has also not been clear up till now, why the method sometimes does not work. In this paper, we present an analytical model for the modified Herzog test, which explains why the test never gives a false result. We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others. PMID:24020614

  18. Determining the fibrillar orientation of bast fibres with polarized light microscopy: the modified Herzog test (red plate test) explained.

    PubMed

    Haugan, E; Holst, B

    2013-11-01

    The identification of bast fibre samples, in particular, bast fibres used in textiles, is an important issue in archaeology, criminology and other scientific fields. One of the characteristic features of bast fibres is their fibrillar orientation, referred to as Z- or S twist (or alternatively right- and left-handed fibres). An empirical test for determining the fibrillar orientation using polarized light microscopy has been known in the community for many years. It is referred to as the modified Herzog test or red plate test. The test has the reputation for never producing false results, but also for occasionally not working. However, so far, no proper justification has been provided in the literature that the 'no false results' assumption is really correct and it has also not been clear up till now, why the method sometimes does not work. In this paper, we present an analytical model for the modified Herzog test, which explains why the test never gives a false result. We also provide an explanation for why the Herzog test sometimes does not work: According to our model, the Herzog test will not work if none of the three distinct layers in the secondary cell wall is significantly thicker than the others.

  19. Ribosomal genes in focus: new transcripts label the dense fibrillar components and form clusters indicative of "Christmas trees" in situ.

    PubMed

    Koberna, Karel; Malínský, Jan; Pliss, Artem; Masata, Martin; Vecerova, Jaromíra; Fialová, Markéta; Bednár, Jan; Raska, Ivan

    2002-05-27

    T he organization of transcriptionally active ribosomal genes in animal cell nucleoli is investigated in this study in order to address the long-standing controversy with regard to the intranucleolar localization of these genes. Detailed analyses of HeLa cell nucleoli include direct localization of ribosomal genes by in situ hybridization and their indirect localization via nascent ribosomal transcript mappings. On the light microscopy (LM) level, ribosomal genes map in 10-40 fluorescence foci per nucleus, and transcription activity is associated with most foci. We demonstrate that each nucleolar focus observed by LM corresponds, on the EM level, to an individual fibrillar center (FC) and surrounding dense fibrillar components (DFCs). The EM data identify the DFC as the nucleolar subcompartment in which rRNA synthesis takes place, consistent with detection of rDNA within the DFC. The highly sensitive method for mapping nascent transcripts in permeabilized cells on ultrastructural level provides intense and unambiguous clustered immunogold signal over the DFC, whereas very little to no label is detected over the FC. This signal is strongly indicative of nascent "Christmas trees" of rRNA associated with individual rDNA genes, sampled on the surface of thin sections. Stereological analysis of the clustered transcription signal further suggests that these Christmas trees may be contorted in space and exhibit a DNA compaction ratio on the order of 4-5.5.

  20. Vitamin B12[c-lactone], a biologically inactive corrinoid compound, occurs in cultured and dried lion's mane mushroom (Hericium erinaceus) fruiting bodies.

    PubMed

    Teng, Fei; Bito, Tomohiro; Takenaka, Shigeo; Yabuta, Yukinori; Watanabe, Fumio

    2014-02-19

    This study determined the vitamin B12 content of the edible medicinal mushroom Hericium erinaceus, lion's mane mushroom fruiting body, using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.04-0.36 μg/100 g dry weight) of vitamin B12 were found in most of the dried mushroom samples, and two samples contained slightly higher levels (0.56 and 1.04 μg/100 g dry weight, respectively) of vitamin B12. We purified the corrinoid compounds from the extracts of dried lion's mane mushroom fruiting bodies using an immunoaffinity column and identified them as vitamin B12 or vitamin B12[c-lactone] (or both) based on LC/ESI-MS/MS chromatograms. This is the first report on an unnatural corrinoid, vitamin B12[c-lactone], occurring in foods. Vitamin B12[c-lactone] was simple to produce during incubation of authentic vitamin B12 and chloramine-T, an antimicrobial agent, at varying pH values (3.0-7.0) and was completely inactive in the vitamin B12-dependent bacteria that are generally used in vitamin B12 bioassays.

  1. Biological liquid crystal elastomers.

    PubMed

    Knight, David P; Vollrath, Fritz

    2002-02-28

    Liquid crystal elastomers (LCEs) have recently been described as a new class of matter. Here we review the evidence for the novel conclusion that the fibrillar collagens and the dragline silks of orb web spiders belong to this remarkable class of materials. Unlike conventional rubbers, LCEs are ordered, rather than disordered, at rest. The identification of these biopolymers as LCEs may have a predictive value. It may explain how collagens and spider dragline silks are assembled. It may provide a detailed explanation for their mechanical properties, accounting for the variation between different members of the collagen family and between the draglines in different spider species. It may provide a basis for the design of biomimetic collagen and dragline silk analogues by genetic engineering, peptide- or classical polymer synthesis. Biological LCEs may exhibit a range of exotic properties already identified in other members of this remarkable class of materials. In this paper, the possibility that other transversely banded fibrillar proteins are also LCEs is discussed.

  2. Effect of curcumin and Cu 2+/Zn 2+ ions on the fibrillar aggregates formed by the amyloid peptide and other peptides at the organic-aqueous interface

    NASA Astrophysics Data System (ADS)

    Sanghamitra, Nusrat J. M.; Varghese, Neenu; Rao, C. N. R.

    2010-08-01

    Characteristic features of a perilous neuro-degenerative disease such as the Alzhiemer's disease is fibrillar plaque formation by the amyloid (Aβ) peptide. We have modelled the formation and disintegration of fibrils by studying the aggregate structures formed by Aβ structural motif diphenylalanine as well as insulin and bovine serum albumin at the organic-aqueous interface. Even small concentrations of curcumin in the organic medium or Cu 2+ and Zn 2+ ions in the aqueous medium are found to break down the fibrillar structures.

  3. Fibrillar structure and elasticity of hydrating collagen: a quantitative multiscale approach.

    PubMed

    Morin, Claire; Hellmich, Christian; Henits, Peter

    2013-01-21

    It is well known that hydration of collagenous tissues leads to their swelling, as well as to softening of their elastic behavior. However, it is much less clear which microstructural and micromechanical "rules" are involved in this process. Here, we develop a theoretical approach cast in analytical mathematical formulations, which is experimentally validated by a wealth of independent tests on collagenous tissues, such as X-ray diffraction, vacuum drying, mass measurements, and Brillouin light scattering. The overall emerging picture is the following: air-drying leaves water only in the gap zones between the triple-helical collagen molecules; upon re-hydration, the extrafibrillar space is established at volumes directly proportional to the hydration-induced swelling of the (micro) fibrils, until the maximum equatorial distance between the long collagen molecules is reached. Thereafter, the volume of the fibrils stays constant, and only the extrafibrillar volume continues to grow. At all these hydration stages, the elastic behavior is governed by the same, hydration-invariant mechanical interaction pattern of only two, interpenetrating mechanical phases: transversely isotropic molecular collagen and isotropic water (or empty pores in the vacuum-dried case).

  4. century drying

    NASA Astrophysics Data System (ADS)

    Cook, Benjamin I.; Smerdon, Jason E.; Seager, Richard; Coats, Sloan

    2014-11-01

    Global warming is expected to increase the frequency and intensity of droughts in the twenty-first century, but the relative contributions from changes in moisture supply (precipitation) versus evaporative demand (potential evapotranspiration; PET) have not been comprehensively assessed. Using output from a suite of general circulation model (GCM) simulations from phase 5 of the Coupled Model Intercomparison Project, projected twenty-first century drying and wetting trends are investigated using two offline indices of surface moisture balance: the Palmer Drought Severity Index (PDSI) and the Standardized Precipitation Evapotranspiration Index (SPEI). PDSI and SPEI projections using precipitation and Penman-Monteith based PET changes from the GCMs generally agree, showing robust cross-model drying in western North America, Central America, the Mediterranean, southern Africa, and the Amazon and robust wetting occurring in the Northern Hemisphere high latitudes and east Africa (PDSI only). The SPEI is more sensitive to PET changes than the PDSI, especially in arid regions such as the Sahara and Middle East. Regional drying and wetting patterns largely mirror the spatially heterogeneous response of precipitation in the models, although drying in the PDSI and SPEI calculations extends beyond the regions of reduced precipitation. This expansion of drying areas is attributed to globally widespread increases in PET, caused by increases in surface net radiation and the vapor pressure deficit. Increased PET not only intensifies drying in areas where precipitation is already reduced, it also drives areas into drought that would otherwise experience little drying or even wetting from precipitation trends alone. This PET amplification effect is largest in the Northern Hemisphere mid-latitudes, and is especially pronounced in western North America, Europe, and southeast China. Compared to PDSI projections using precipitation changes only, the projections incorporating both

  5. Molecular, biochemical and functional analysis of a novel and developmentally important fibrillar collagen (Hcol-I) in hydra.

    PubMed

    Deutzmann, R; Fowler, S; Zhang, X; Boone, K; Dexter, S; Boot-Handford, R P; Rachel, R; Sarras, M P

    2000-11-01

    The body wall of hydra (a member of the phylum Cnidaria) is structurally reduced to an epithelial bilayer with an intervening extracellular matrix (ECM). Previous studies have established that cell-ECM interactions are important for morphogenesis and cell differentiation in this simple metazoan. The ECM of hydra is particularly interesting because it represents a primordial form of matrix. Despite progress in our understanding of hydra ECM, we still know little about the nature of hydra collagens. In the current study we provide a molecular, biochemical and functional analysis of a hydra fibrillar collagen that has similarity to vertebrate type I and type II collagens. This fibrillar collagen has been named hydra collagen-I (Hcol-I) because of its structure and because it is the first ECM collagen to be identified in hydra. It represents a novel member of the collagen family. Similar to vertebrate type I and II collagens, Hcol-I contains an N-terminal propeptide-like domain, a triple helical domain containing typical Gly-X-Y repeats and a C-terminal propeptide domain. The overall identity to vertebrate fibrillar collagens is about 30%, while the identity of the C-terminal propeptide domain is 50%. Because the N-terminal propeptide domain is retained after post-translational processing, Hcol-I does not form thick fibers as seen in vertebrates. This was confirmed using transmission electron microscopy to study rotary shadow images of purified Hcol-I. In addition, absence of crucial lysine residues and an overall reduction in proline content, results in reduced crosslinking of fibrils and increased flexibility of the molecule, respectively. These structural changes in Hcol-I help to explain the flexible properties of hydra ECM. Immunocytochemical studies indicate that Hcol-I forms the 10 nm fibrils that comprise the majority of molecules in the central fibrous zone of hydra ECM. The central fibrous zone resides between the two subepithelial zones where hydra laminin

  6. Antimicrobial peptide (Cn-AMP2) from liquid endosperm of Cocos nucifera forms amyloid-like fibrillar structure.

    PubMed

    Gour, Shalini; Kaushik, Vibha; Kumar, Vijay; Bhat, Priyanka; Yadav, Subhash C; Yadav, Jay K

    2016-04-01

    Cn-AMP2 is an antimicrobial peptide derived from liquid endosperm of coconut (Cocos nucifera). It consists of 11 amino acid residues and predicted to have high propensity for β-sheet formation that disposes this peptide to be amyloidogenic. In the present study, we have examined the amyloidogenic propensities of Cn-AMP2 in silico and then tested the predictions under in vitro conditions. The in silico study revealed that the peptide possesses high amyloidogenic propensity comparable with Aβ. Upon solubilisation and agitation in aqueous buffer, Cn-AMP2 forms visible aggregates that display bathochromic shift in the Congo red absorbance spectra, strong increase in thioflavin T fluorescence and fibrillar morphology under transmission electron microscopy. All these properties are typical of an amyloid fibril derived from various proteins/peptides including Aβ. PMID:27028204

  7. Glial fibrillar acidic protein in the cerebrospinal fluid of Alzheimer's disease, dementia with Lewy bodies, and frontotemporal lobar degeneration.

    PubMed

    Ishiki, Aiko; Kamada, Maki; Kawamura, Yuki; Terao, Chiaki; Shimoda, Fumiko; Tomita, Naoki; Arai, Hiroyuki; Furukawa, Katsutoshi

    2016-01-01

    Biomarkers in the cerebrospinal fluid (CSF) are currently regarded as indispensable indicators for accurate differential diagnosis of neurodegenerative disorders. Although high levels of astrocyte-secreted glial fibrillar acidic protein (GFAP) in the CSF of patients with Alzheimer's disease (AD) have been reported, the levels of GFAP in the CSF have not been fully investigated in other neurological disorders that cause dementia, such as dementia with Lewy bodies (DLB) and frontotemporal lobar degeneration (FTLD). In this study, we determined the levels of GFAP in the CSF of healthy control subjects and AD, DLB, and FTLD patients to address two questions: (i) Do the levels of GFAP differ among these disorders? and (ii) Can GFAP be used as a biomarker for the differential diagnosis of these neurodegenerative disorders? The levels of GFAP in AD, DLB, and FTLD patients were significantly higher than those in the healthy control subjects. Although the levels of GFAP were not significantly different between AD and DLB patients, a higher level of GFAP was observed in FTLD patients than in AD and DLB patients. It is concluded that representative neurological disorders causing dementia were associated with higher levels of GFAP in the CSF. We propose the following mechanism concerning the amount of glial fibrillar acidic protein (GFAP) in the cerebrospinal fluid (CSF) in Alzheimer's disease (AD), dementia with Lewy bodies (DLB), and frontotemporal lobar degeneration (FTLD). The increase in the release of GFAP into CSF is considered to reflect the sum of degeneration of astrocytes and astrocytosis. The sum of degeneration and astrocytosis or the GFAP release could be in the order of FTLD > DLB > AD > normal condition.

  8. Dry cell battery poisoning

    MedlinePlus

    Batteries - dry cell ... Acidic dry cell batteries contain: Manganese dioxide Ammonium chloride Alkaline dry cell batteries contain: Sodium hydroxide Potassium hydroxide Lithium dioxide dry cell batteries ...

  9. Complete structural organization of the human {alpha}1(V) collagen gene (COL5A1): Divergence from the conserved organization of other characterized fibrillar collagen genes

    SciTech Connect

    Takahara, Kazuhiko; Hoffman, G.G.; Greenspan, D.S.

    1995-10-10

    Genes that encode the vertebrate fibrillar collagen types I-III have previously been shown to share a highly conserved intron/exon organization, thought to reflect common ancestry and evolutionary pressures at the protein level. We report here the complete intron/exon organization of COL5A1, the human gene that encodes the {alpha}1 chain of fibrillar collagen type V. The structure of COL5A1 is shown to be considerably diverged from the conserved structure of the genes for fibrillar collagen types I-III. COL5A1 has 66 exons, which is greater than the number of exons found in the genes for collagen types I-III. The increased number of exons is partly due to the increased size of the pro-{alpha}1(V) N-propeptide, relative to the sizes of the N-propeptides of the types I-III procollagen molecules. In addition, however, the increased number of exons is due to differences in the intron/exon organization of the triple-helix coding region of COL5A1 compared to the organization of the triple-helix coding regions of the genes for collagen types I-III. Of particular interest is the increase of 54 bp exons in this region of COL5A1, strongly supporting the proposal that the triple-helix coding regions of fibrillar collagen genes evolved from duplication of a 54 bp primordial genetic element. Moreover, comparison of the structure of COL5A1 to the highly conserved structure of the genes of collagen types I-III provides insights into the probable structure of the ancestral gene that gave rise to what appears to be two classes of vertebrate fibrillar collagen genes. 50 refs., 5 figs.

  10. A tailless timing belt climbing platform utilizing dry adhesives with mushroom caps

    NASA Astrophysics Data System (ADS)

    Krahn, J.; Liu, Y.; Sadeghi, A.; Menon, C.

    2011-11-01

    In many instances, a climbing robot that utilizes dry adhesives as an attachment method may be found to be very useful due to the inherent nature of biomimetic fibrillar dry adhesives in the applications of space, security, surveillance and nuclear reactor cleaning and maintenance. In this paper, a novel tank-like modular robot is developed that does not require a tail to provide a preload to the front of the robot while climbing. Biomimetic fibrillar dry adhesives with mushroom caps manufactured into belts are used as an attachment method. The manufacturing of the dry adhesive belts is discussed and the adhesion properties are examined. The timing belt based climbing platform (TBCP-II) utilizes two tank-like modules connected with an active joint with continual surface-robot distance measuring providing feedback for active adhesive preloading. The mechanical, electronic and software design is discussed. Reliable vertical surface climbing is achieved and the preloading strategy and response is examined. TBCP-II is shown to be capable of both horizontal to vertical and vertical to horizontal surface transfers over both inside and outside corners.

  11. Evaluation of Biological and Enzymatic Activity of Soil in a Tropical Dry Forest: Desierto de la Tatacoa (Colombia) with Potential in Mars Terraforming and Other Similar Planets

    NASA Astrophysics Data System (ADS)

    Moreno Moreno, A. N.

    2009-12-01

    Desierto de la Tatacoa has been determined to be a tropical dry forest bioma, which is located at 3° 13" N 75° 13" W. It has a hot thermal floor with 440 msnm of altitude; it has a daily average of 28° C, and a maximum of 40° C, Its annual rainfall total can be upwards of 1250 mm. Its solar sheen has a daily average of 5.8 hours and its relative humidity is between 60% and 65%. Therefore, the life forms presents are very scant, and in certain places, almost void. It was realized a completely random sampling of soil from its surface down to 6 inches deep, of zones without vegetation and with soils highly loaded by oxides of iron in order to determine the number of microorganisms per gram and its subsequent identification. It was measured the soil basal respiration. Besides, it was determined enzymatic activity (catalase, dehydrogenase, phosphatase and urease). Starting with the obtained results, it is developes an alternative towards the study of soil genesis in Mars in particular, and recommendations for same process in other planets. Although the information found in the experiments already realized in Martian soil they demonstrate that doesnt exist any enzymatic activity, the knowledge of the same topic in the soil is proposed as an alternative to problems like carbonic fixing of the dense Martian atmosphere of CO2, the degradation of inorganic compounds amongst other in order to prepare the substratum for later colonization by some life form.

  12. Nanoscale Visualization of a Fibrillar Array in the Cell Wall of Filamentous Cyanobacteria and Its Implications for Gliding Motility▿

    PubMed Central

    Read, Nicholas; Connell, Simon; Adams, David G.

    2007-01-01

    Many filamentous cyanobacteria are motile by gliding, which requires attachment to a surface. There are two main theories to explain the mechanism of gliding. According to the first, the filament is pushed forward by small waves that pass along the cell surface. In the second, gliding is powered by the extrusion of slime through pores surrounding each cell septum. We have previously shown that the cell walls of several motile cyanobacteria possess an array of parallel fibrils between the peptidoglycan and the outer membrane and have speculated that the function of this array may be to generate surface waves to power gliding. Here, we report on a study of the cell surface topography of two morphologically different filamentous cyanobacteria, using field emission gun scanning electron microscopy (FEGSEM) and atomic force microscopy (AFM). FEGSEM and AFM images of Oscillatoria sp. strain A2 confirmed the presence of an array of fibrils, visible as parallel corrugations on the cell surface. These corrugations were also visualized by AFM scanning of fully hydrated filaments under liquid; this has not been achieved before for filamentous bacteria. FEGSEM images of Nostoc punctiforme revealed a highly convoluted, not parallel, fibrillar array. We conclude that an array of parallel fibrils, beneath the outer membrane of Oscillatoria, may function in the generation of thrust in gliding motility. The array of convoluted fibrils in N. punctiforme may have an alternative function, perhaps connected with the increase in outer membrane surface area resulting from the presence of the fibrils. PMID:17693519

  13. Quercetin protects human brain microvascular endothelial cells from fibrillar β-amyloid1–40-induced toxicity

    PubMed Central

    Li, Yongjie; Zhou, Sibai; Li, Jinze; Sun, Yuhua; Hasimu, Hamlati; Liu, Rui; Zhang, Tiantai

    2015-01-01

    Amyloid beta-peptides (Aβ) are known to undergo active transport across the blood-brain barrier, and cerebral amyloid angiopathy has been shown to be a prominent feature in the majority of Alzheimer׳s disease. Quercetin is a natural flavonoid molecule and has been demonstrated to have potent neuroprotective effects, but its protective effect on endothelial cells under Aβ-damaged condition is unclear. In the present study, the protective effects of quercetin on brain microvascular endothelial cells injured by fibrillar Aβ1–40 (fAβ1–40) were observed. The results show that fAβ1–40-induced cytotoxicity in human brain microvascular endothelial cells (hBMECs) can be relieved by quercetin treatment. Quercetin increases cell viability, reduces the release of lactate dehydrogenase, and relieves nuclear condensation. Quercetin also alleviates intracellular reactive oxygen species generation and increases superoxide dismutase activity. Moreover, it strengthens the barrier integrity through the preservation of the transendothelial electrical resistance value, the relief of aggravated permeability, and the increase of characteristic enzyme levels after being exposed to fAβ1–40. In conclusion, quercetin protects hBMECs from fAβ1–40-induced toxicity. PMID:26579424

  14. Characterization of the Six Zebrafish Clade B Fibrillar Procollagen Genes, with Evidence for Evolutionarily Conserved Alternative Splicing within the pro-α1(V) C-propeptide

    PubMed Central

    Hoffman, Guy G.; Branam, Amanda M.; Huang, Guorui; Pelegri, Francisco; Cole, William G.; Wenstrup, Richard M.; Greenspan, Daniel S.

    2010-01-01

    Genes for tetrapod fibrillar procollagen chains can be divided into two clades, A and B, based on sequence homologies and differences in protein domain and gene structures. Although the major fibrillar collagen types I–III comprise only clade A chains, the minor fibrillar collagen types V and XI comprise both clade A chains and the clade B chains pro-α1(V), pro-α3(V), pro-α1(XI) and pro-α2(XI), in which defects can underlie various genetic connective tissue disorders. Here we characterize the clade B procollagen chains of zebrafish. We demonstrate that in contrast to the four tetrapod clade B chains, zebrafish have six clade B chains, designated here as pro-α1(V), proα3(V)a and b, pro-α1(XI)a and b, and pro-α2(XI), based on synteny, sequence homologies, and features of protein domain and gene structures. Spatiotemporal expression patterns are described, as are conserved and non-conserved features that provide insights into the function and evolution of the clade B chain types. Such features include differential alternative splicing of NH2-terminal globular sequences and the first case of a non-triple helical imperfection in the COL1 domain of a clade B, or clade A, fibrillar procollagen chain. Evidence is also provided for previously unknown and evolutionarily conserved alternative splicing within the pro-α1(V) C-propeptide, which may affect selectivity of collagen type V/XI chain associations in species ranging from zebrafish to human. Data presented herein provide insights into the nature of clade B procollagen chains and should facilitate their study in the zebrafish model system. PMID:20102740

  15. Drying Thermoplastics

    NASA Technical Reports Server (NTRS)

    1976-01-01

    In searching for an improved method of removing water from polyester type resins without damaging the materials, Conair Inc. turned to the NASA Center at the University of Pittsburgh for assistance. Taking an organized, thorough look at existing technology before beginning research has helped many companies save significant time and money. They searched the NASA and other computerized files for microwave drying of thermoplastics. About 300 relevant citations were retrieved - eight of which were identified as directly applicable to the problem. Company estimates it saved a minimum of a full year in compiling research results assembled by the information center.

  16. Brain propagation of transduced α-synuclein involves non-fibrillar protein species and is enhanced in α-synuclein null mice.

    PubMed

    Helwig, Michael; Klinkenberg, Michael; Rusconi, Raffaella; Musgrove, Ruth E; Majbour, Nour K; El-Agnaf, Omar M A; Ulusoy, Ayse; Di Monte, Donato A

    2016-03-01

    Aggregation and neuron-to-neuron transmission are attributes of α-synuclein relevant to its pathogenetic role in human synucleinopathies such as Parkinson's disease. Intraparenchymal injections of fibrillar α-synuclein trigger widespread propagation of amyloidogenic protein species via mechanisms that require expression of endogenous α-synuclein and, possibly, its structural corruption by misfolded conformers acting as pathological seeds. Here we describe another paradigm of long-distance brain diffusion of α-synuclein that involves inter-neuronal transfer of monomeric and/or oligomeric species and is independent of recruitment of the endogenous protein. Targeted expression of human α-synuclein was induced in the mouse medulla oblongata through an injection of viral vectors into the vagus nerve. Enhanced levels of intra-neuronal α-synuclein were sufficient to initiate its caudo-rostral diffusion that likely involved at least one synaptic transfer and progressively reached specific brain regions such as the locus coeruleus, dorsal raphae and amygdala in the pons, midbrain and forebrain. Transfer of human α-synuclein was compared in two separate lines of α-synuclein-deficient mice versus their respective wild-type controls and, interestingly, lack of endogenous α-synuclein expression did not counteract diffusion but actually resulted in a more pronounced and advanced propagation of exogenous α-synuclein. Self-interaction of adjacent molecules of human α-synuclein was detected in both wild-type and mutant mice. In the former, interaction of human α-synuclein with mouse α-synuclein was also observed and might have contributed to differences in protein transmission. In wild-type and α-synuclein-deficient mice, accumulation of human α-synuclein within recipient axons in the pons, midbrain and forebrain caused morphological evidence of neuritic pathology. Tissue sections from the medulla oblongata and pons were stained with different antibodies recognizing

  17. Brain propagation of transduced α-synuclein involves non-fibrillar protein species and is enhanced in α-synuclein null mice.

    PubMed

    Helwig, Michael; Klinkenberg, Michael; Rusconi, Raffaella; Musgrove, Ruth E; Majbour, Nour K; El-Agnaf, Omar M A; Ulusoy, Ayse; Di Monte, Donato A

    2016-03-01

    Aggregation and neuron-to-neuron transmission are attributes of α-synuclein relevant to its pathogenetic role in human synucleinopathies such as Parkinson's disease. Intraparenchymal injections of fibrillar α-synuclein trigger widespread propagation of amyloidogenic protein species via mechanisms that require expression of endogenous α-synuclein and, possibly, its structural corruption by misfolded conformers acting as pathological seeds. Here we describe another paradigm of long-distance brain diffusion of α-synuclein that involves inter-neuronal transfer of monomeric and/or oligomeric species and is independent of recruitment of the endogenous protein. Targeted expression of human α-synuclein was induced in the mouse medulla oblongata through an injection of viral vectors into the vagus nerve. Enhanced levels of intra-neuronal α-synuclein were sufficient to initiate its caudo-rostral diffusion that likely involved at least one synaptic transfer and progressively reached specific brain regions such as the locus coeruleus, dorsal raphae and amygdala in the pons, midbrain and forebrain. Transfer of human α-synuclein was compared in two separate lines of α-synuclein-deficient mice versus their respective wild-type controls and, interestingly, lack of endogenous α-synuclein expression did not counteract diffusion but actually resulted in a more pronounced and advanced propagation of exogenous α-synuclein. Self-interaction of adjacent molecules of human α-synuclein was detected in both wild-type and mutant mice. In the former, interaction of human α-synuclein with mouse α-synuclein was also observed and might have contributed to differences in protein transmission. In wild-type and α-synuclein-deficient mice, accumulation of human α-synuclein within recipient axons in the pons, midbrain and forebrain caused morphological evidence of neuritic pathology. Tissue sections from the medulla oblongata and pons were stained with different antibodies recognizing

  18. Dry Mouth or Xerostomia

    MedlinePlus

    ... or Xerostomia Request Permissions Print to PDF Dry Mouth or Xerostomia Approved by the Cancer.Net Editorial ... a dry mouth. Signs and symptoms of dry mouth The signs and symptoms of dry mouth include ...

  19. Nonlinear Surface Dilatational Rheology and Foaming Behavior of Protein and Protein Fibrillar Aggregates in the Presence of Natural Surfactant.

    PubMed

    Wan, Zhili; Yang, Xiaoquan; Sagis, Leonard M C

    2016-04-19

    The surface and foaming properties of native soy glycinin (11S) and its heat-induced fibrillar aggregates, in the presence of natural surfactant steviol glycoside (STE), were investigated and compared at pH 7.0 to determine the impact of protein structure modification on protein-surfactant interfacial interactions. The adsorption at, and nonlinear dilatational rheological behavior of, the air-water interface were studied by combining drop shape analysis tensiometry, ellipsometry, and large-amplitude oscillatory dilatational rheology. Lissajous plots of surface pressure versus deformation were used to analyze the surface rheological response in terms of interfacial microstructure. The heat treatment generates a mixture of long fibrils and unconverted peptides. The presence of small peptides in 11S fibril samples resulted in a faster adsorption kinetics than that of native 11S. The addition of STE affected the adsorption of 11S significantly, whereas no apparent effect on the adsorption of the 11S fibril-peptide system was observed. The rheological response of interfaces stabilized by 11S-STE mixtures also differed significantly from the response for 11S fibril-peptide-STE mixtures. For 11S, the STE reduces the degree of strain hardening in extension and increases strain hardening in compression, suggesting the interfacial structure may change from a surface gel to a mixed phase of protein patches and STE domains. The foams generated from the mixtures displayed comparable foam stability to that of pure 11S. For 11S fibril-peptide mixtures STE only significantly affects the response in extension, where the degree of strain softening is decreased compared to the pure fibril-peptide system. The foam stability of the fibril-peptide system was significantly reduced by STE. These findings indicate that fibrillization of globular proteins could be a potential strategy to modify the complex surface and foaming behaviors of protein-surfactant mixtures.

  20. Nonlinear Surface Dilatational Rheology and Foaming Behavior of Protein and Protein Fibrillar Aggregates in the Presence of Natural Surfactant.

    PubMed

    Wan, Zhili; Yang, Xiaoquan; Sagis, Leonard M C

    2016-04-19

    The surface and foaming properties of native soy glycinin (11S) and its heat-induced fibrillar aggregates, in the presence of natural surfactant steviol glycoside (STE), were investigated and compared at pH 7.0 to determine the impact of protein structure modification on protein-surfactant interfacial interactions. The adsorption at, and nonlinear dilatational rheological behavior of, the air-water interface were studied by combining drop shape analysis tensiometry, ellipsometry, and large-amplitude oscillatory dilatational rheology. Lissajous plots of surface pressure versus deformation were used to analyze the surface rheological response in terms of interfacial microstructure. The heat treatment generates a mixture of long fibrils and unconverted peptides. The presence of small peptides in 11S fibril samples resulted in a faster adsorption kinetics than that of native 11S. The addition of STE affected the adsorption of 11S significantly, whereas no apparent effect on the adsorption of the 11S fibril-peptide system was observed. The rheological response of interfaces stabilized by 11S-STE mixtures also differed significantly from the response for 11S fibril-peptide-STE mixtures. For 11S, the STE reduces the degree of strain hardening in extension and increases strain hardening in compression, suggesting the interfacial structure may change from a surface gel to a mixed phase of protein patches and STE domains. The foams generated from the mixtures displayed comparable foam stability to that of pure 11S. For 11S fibril-peptide mixtures STE only significantly affects the response in extension, where the degree of strain softening is decreased compared to the pure fibril-peptide system. The foam stability of the fibril-peptide system was significantly reduced by STE. These findings indicate that fibrillization of globular proteins could be a potential strategy to modify the complex surface and foaming behaviors of protein-surfactant mixtures. PMID:27043221

  1. Structural properties of fibrillar proteins isolated from the cell surface and cytoplasm of Streptococcus salivarius (K+) cells and nonadhesive mutants.

    PubMed Central

    Weerkamp, A H; van der Mei, H C; Liem, R S

    1986-01-01

    Most Streptococcus salivarius (K+) cells contain two protein antigens with different adhesive functions. The subcellular distribution and some structural properties of purified proteins were studied. Antigen B (AgB), a protein involved in interbacterial coaggregation with gram-negative bacteria, was present in the cell wall fraction only of the wild-type strain and was absent from the cells of a nonadhesive mutant. Antigen C (AgC), a glycoprotein involved in host-associated adhesive functions, was predominantly associated with the cell wall of the wild-type strain (AgCw), but accumulated in high amounts in the cytoplasmic fraction (AgCin) of mutants lacking the wall-associated form. AgB, AgCw, and AgCin had molecular weights of 380,000, 250,000 to 320,000, and 488,000, respectively, upon gel electrophoresis under nondenaturing conditions. In the presence of sodium dodecyl sulfate and beta-mercaptoethanol the molecular weights were only slightly lower, suggesting that the free, isolated molecules exist as monomers under native conditions. AgCin readily stained with periodate-Schiff reagent, indicating a significant content of carbohydrate, similar to AgCw. Circular dichroism spectra showed that about 45% of the amino acids of AgCw were involved in alpha-helical coiled structures. AgB had a significantly lower proportion of ordered coiled structure. Electron microscopic observations of low-angle-shadowed preparations of purified antigens showed that they were flexible, thin rods with thickened or globular ends. Measurements corrected for shadow thickness showed lengths of 184 nm (AgB), 112 nm (AgCin), and 87 nm (AgCw). Treatment of AgCw with protease destroyed the fibrillar core, but seemed not to affect the globular ends. Comparison of the results with the localization of the antigens in wild-type and specific mutant strains suggested that each antigen molecule may represent a single, characteristic surface fibril with a specific adhesive capacity. Images PMID

  2. Data in support of the identification of neuronal and astrocyte proteins interacting with extracellularly applied oligomeric and fibrillar α-synuclein assemblies by mass spectrometry

    PubMed Central

    Shrivastava, Amulya Nidhi; Redeker, Virginie; Fritz, Nicolas; Pieri, Laura; Almeida, Leandro G.; Spolidoro, Maria; Liebmann, Thomas; Bousset, Luc; Renner, Marianne; Léna, Clément; Aperia, Anita; Melki, Ronald; Triller, Antoine

    2016-01-01

    α-Synuclein (α-syn) is the principal component of Lewy bodies, the pathophysiological hallmark of individuals affected by Parkinson disease (PD). This neuropathologic form of α-syn contributes to PD progression and propagation of α-syn assemblies between neurons. The data we present here support the proteomic analysis used to identify neuronal proteins that specifically interact with extracellularly applied oligomeric or fibrillar α-syn assemblies (conditions 1 and 2, respectively) (doi: 10.15252/embj.201591397[1]). α-syn assemblies and their cellular partner proteins were pulled down from neuronal cell lysed shortly after exposure to exogenous α-syn assemblies and the associated proteins were identified by mass spectrometry using a shotgun proteomic-based approach. We also performed experiments on pure cultures of astrocytes to identify astrocyte-specific proteins interacting with oligomeric or fibrillar α-syn (conditions 3 and 4, respectively). For each condition, proteins interacting selectively with α-syn assemblies were identified by comparison to proteins pulled-down from untreated cells used as controls. The mass spectrometry data, the database search and the peak lists have been deposited to the ProteomeXchange Consortium database via the PRIDE partner repository with the dataset identifiers PRIDE: PXD002256 to PRIDE: PXD002263 and doi: 10.6019/PXD002256 to 10.6019/PXD002263. PMID:26958642

  3. Data in support of the identification of neuronal and astrocyte proteins interacting with extracellularly applied oligomeric and fibrillar α-synuclein assemblies by mass spectrometry.

    PubMed

    Shrivastava, Amulya Nidhi; Redeker, Virginie; Fritz, Nicolas; Pieri, Laura; Almeida, Leandro G; Spolidoro, Maria; Liebmann, Thomas; Bousset, Luc; Renner, Marianne; Léna, Clément; Aperia, Anita; Melki, Ronald; Triller, Antoine

    2016-06-01

    α-Synuclein (α-syn) is the principal component of Lewy bodies, the pathophysiological hallmark of individuals affected by Parkinson disease (PD). This neuropathologic form of α-syn contributes to PD progression and propagation of α-syn assemblies between neurons. The data we present here support the proteomic analysis used to identify neuronal proteins that specifically interact with extracellularly applied oligomeric or fibrillar α-syn assemblies (conditions 1 and 2, respectively) (doi: 10.15252/embj.201591397[1]). α-syn assemblies and their cellular partner proteins were pulled down from neuronal cell lysed shortly after exposure to exogenous α-syn assemblies and the associated proteins were identified by mass spectrometry using a shotgun proteomic-based approach. We also performed experiments on pure cultures of astrocytes to identify astrocyte-specific proteins interacting with oligomeric or fibrillar α-syn (conditions 3 and 4, respectively). For each condition, proteins interacting selectively with α-syn assemblies were identified by comparison to proteins pulled-down from untreated cells used as controls. The mass spectrometry data, the database search and the peak lists have been deposited to the ProteomeXchange Consortium database via the PRIDE partner repository with the dataset identifiers PRIDE: PXD002256 to PRIDE: PXD002263 and doi: 10.6019/PXD002256 to 10.6019/PXD002263. PMID:26958642

  4. Membranes, metabolism, and dry organisms

    SciTech Connect

    Leopold, A.C.

    1986-01-01

    Our understanding of the ways in which desiccated organisms are protected from destruction by reactions in the dry state is in an early state of development. In this volume, contributions to each of these pathways of research are reported. The wide range of experimental and theoretical approaches, from biological to physicochemical, covers an exciting spectrum, from natural history to reductionist experimentation, and blends physiological, chemical, and physical methods in the pursuit of an understanding of anhydrous biology. Each individual report in this volume is separately abstracted and indexed for the Energy Data Base.

  5. Development of dry gram-negative bacteria biocontrol products and small pilot tests against dry rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pseudomonas fluorescens strains S11:P:12, P22:Y:05, and S22:T:04 suppress four important storage potato maladies; dry rot, late blight, pink rot, and sprouting. Studies were designed to identify methods for producing a dried, efficacious biological control product. The strains were evaluated individ...

  6. Effects of contact cap dimension on dry adhesion of bioinspired mushroom-shaped surfaces

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Shao, Jinyou; Ding, Yucheng; Li, Xiangming; Tian, Hongmiao; Hu, Hong

    2015-03-01

    Dry adhesion observed in small creatures, such as spiders, insects, and geckos, has many great advantages such as repeatability and strong adhesiveness. In order to mimic these unique performances, fibrillar surface with a mushroom shaped end has drawn lots of attentions because of its advantage in efficiently enhancing adhesion compared with other sphere or simple flat ends. Here, in order to study the effects of contact cap dimension on adhesion strength, patterned surfaces of mushroom-shaped micropillars with differing cap diameters are fabricated based on the conventional photolithography and molding. The normal adhesion strength of these dry adhesives with varying cap diameters is measured with home-built equipment. The strength increases with the rise of cap diameter, and interestingly it becomes strongest when the mushroom caps join together.

  7. Patterns from drying drops.

    PubMed

    Sefiane, Khellil

    2014-04-01

    The objective of this review is to investigate different deposition patterns from dried droplets of a range of fluids: paints, polymers and biological fluids. This includes looking at mechanisms controlling the patterns and how they can be manipulated for use in certain applications such as medical diagnostics and nanotechnology. This review introduces the fundamental properties of droplets during evaporation. These include profile evolution (constant contact angle regime (CCAR) and constant radius regime (CRR)) and the internal flow (Marangoni and Capillary flow (Deegan et al. [22])). The understanding of these processes and the basic physics behind the phenomenon are crucial to the understanding of the factors influencing the deposition patterns. It concludes with the applications that each of these fluids can be used in and how the manipulation of the deposition pattern is useful. The most commonly seen pattern is the coffee-ring deposit which can be seen frequently in real life from tea/coffee stains and in water colour painting. This is caused by an outward flow known as capillary flow which carries suspended particles out to the edge of the wetted area. Other patterns that were found were uniform, central deposits and concentric rings which are caused by inward Marangoni flow. Complex biological fluids displayed an array of different patterns which can be used to diagnose patients.

  8. Patterns from drying drops.

    PubMed

    Sefiane, Khellil

    2014-04-01

    The objective of this review is to investigate different deposition patterns from dried droplets of a range of fluids: paints, polymers and biological fluids. This includes looking at mechanisms controlling the patterns and how they can be manipulated for use in certain applications such as medical diagnostics and nanotechnology. This review introduces the fundamental properties of droplets during evaporation. These include profile evolution (constant contact angle regime (CCAR) and constant radius regime (CRR)) and the internal flow (Marangoni and Capillary flow (Deegan et al. [22])). The understanding of these processes and the basic physics behind the phenomenon are crucial to the understanding of the factors influencing the deposition patterns. It concludes with the applications that each of these fluids can be used in and how the manipulation of the deposition pattern is useful. The most commonly seen pattern is the coffee-ring deposit which can be seen frequently in real life from tea/coffee stains and in water colour painting. This is caused by an outward flow known as capillary flow which carries suspended particles out to the edge of the wetted area. Other patterns that were found were uniform, central deposits and concentric rings which are caused by inward Marangoni flow. Complex biological fluids displayed an array of different patterns which can be used to diagnose patients. PMID:23746427

  9. BIOMASS DRYING TECHNOLOGIES

    EPA Science Inventory

    The report examines the technologies used for drying of biomass and the energy requirements of biomass dryers. Biomass drying processes, drying methods, and the conventional types of dryers are surveyed generally. Drying methods and dryer studies using superheated steam as the d...

  10. Biological and biophysics aspects of metformin-induced effects: cortex mitochondrial dysfunction and promotion of toxic amyloid pre-fibrillar aggregates.

    PubMed

    Picone, Pasquale; Vilasi, Silvia; Librizzi, Fabio; Contardi, Marco; Nuzzo, Domenico; Caruana, Luca; Baldassano, Sara; Amato, Antonella; Mulè, Flavia; San Biagio, Pier Luigi; Giacomazza, Daniela; Di Carlo, Marta

    2016-08-01

    The onset of Alzheimer disease (AD) is influenced by several risk factors comprising diabetes. Within this context, antidiabetic drugs, including metformin, are investigated for their effect on AD. We report that in the C57B6/J mice, metformin is delivered to the brain where activates AMP-activated kinase (AMPK), its molecular target. This drug affects the levels of β-secretase (BACE1) and β-amyloid precursor protein (APP), promoting processing and aggregation of β-amyloid (Aβ), mainly in the cortex region. Moreover, metformin induces mitochondrial dysfunction and cell death by affecting the level and conformation of Translocase of the Outer Membrane 40 (TOM40), voltage-dependent anion-selective channels 1 (VDAC1) and hexokinase I (HKI), proteins involved in mitochondrial transport of molecules, including Aβ. By using biophysical techniques we found that metformin is able to directly interact with Aβ influencing its aggregation kinetics and features. These findings indicate that metformin induces different adverse effects, leading to an overall increase of the risk of AD onset. PMID:27509335

  11. Biological and biophysics aspects of metformin-induced effects: cortex mitochondrial dysfunction and promotion of toxic amyloid pre-fibrillar aggregates

    PubMed Central

    Picone, Pasquale; Vilasi, Silvia; Librizzi, Fabio; Contardi, Marco; Nuzzo, Domenico; Caruana, Luca; Baldassano, Sara; Amato, Antonella; Mulè, Flavia; San Biagio, Pier Luigi; Giacomazza, Daniela; Di Carlo, Marta

    2016-01-01

    The onset of Alzheimer disease (AD) is influenced by several risk factors comprising diabetes. Within this context, antidiabetic drugs, including metformin, are investigated for their effect on AD. We report that in the C57B6/J mice, metformin is delivered to the brain where activates AMP-activated kinase (AMPK), its molecular target. This drug affects the levels of β-secretase (BACE1) and β-amyloid precursor protein (APP), promoting processing and aggregation of β-amyloid (Aβ), mainly in the cortex region. Moreover, metformin induces mitochondrial dysfunction and cell death by affecting the level and conformation of Translocase of the Outer Membrane 40 (TOM40), voltage-dependent anion-selective channels 1 (VDAC1) and hexokinase I (HKI), proteins involved in mitochondrial transport of molecules, including Aβ. By using biophysical techniques we found that metformin is able to directly interact with Aβ influencing its aggregation kinetics and features. These findings indicate that metformin induces different adverse effects, leading to an overall increase of the risk of AD onset. PMID:27509335

  12. Unprecedented Route to Ordered Polyaniline: Direct Synthesis of Highly Crystalline Fibrillar Films with Strong π-π Stacking Alignment.

    PubMed

    Gospodinova, Natalia; Ivanov, Dimitri A; Anokhin, Denis V; Mihai, Iulia; Vidal, Loïc; Brun, Sulyvan; Romanova, Julia; Tadjer, Alia

    2009-01-01

    Films of polyaniline (PANI) featuring about 80% crystallinity and characterised with strong π-π stacking alignment parallel to the film surface have been obtained directly after the original synthesis upon simple drying of the aqueous PANI suspension. A strong anisotropy in the growth of the nano-sized crystals produced during the synthesis results in the formation of micrometer-length fibrils perpendicular to the film surface in the course of water evaporation. The regular intercalation of water molecules between the PANI chains seems to be crucial for their ordering throughout the synthesis and film formation.

  13. Friction and adhesion of hierarchical carbon nanotube structures for biomimetic dry adhesives: multiscale modeling.

    PubMed

    Hu, Shihao; Jiang, Haodan; Xia, Zhenhai; Gao, Xiaosheng

    2010-09-01

    With unique hierarchical fibrillar structures on their feet, gecko lizards can walk on vertical walls or even ceilings. Recent experiments have shown that strong binding along the shear direction and easy lifting in the normal direction can be achieved by forming unidirectional carbon nanotube array with laterally distributed tips similar to gecko's feet. In this study, a multiscale modeling approach was developed to analyze friction and adhesion behaviors of this hierarchical fibrillar system. Vertically aligned carbon nanotube array with laterally distributed segments at the end was simulated by coarse grained molecular dynamics. The effects of the laterally distributed segments on friction and adhesion strengths were analyzed, and further adopted as cohesive laws used in finite element analysis at device scale. The results show that the laterally distributed segments play an essential role in achieving high force anisotropy between normal and shear directions in the adhesives. Finite element analysis reveals a new friction-enhanced adhesion mechanism of the carbon nanotube array, which also exists in gecko adhesive system. The multiscale modeling provides an approach to bridge the microlevel structures of the carbon nanotube array with its macrolevel adhesive behaviors, and the predictions from this modeling give an insight into the mechanisms of gecko-mimicking dry adhesives.

  14. Dry Mouth (Xerostomia)

    MedlinePlus

    ... Gum Disease TMJ Disorders Oral Cancer Dry Mouth Burning Mouth Tooth Decay See All Oral Complications of Systemic ... mouth trouble chewing, swallowing, tasting, or speaking a burning feeling in the mouth a dry feeling in the throat cracked lips ...

  15. Dry Skin (Xerosis)

    MedlinePlus

    ... skin, which may bleed if severe. Chapped or cracked lips. When dry skin cracks, germs can get ... cause the skin to become dry, raw, and cracked. Swimming : Some pools have high levels of chlorine, ...

  16. Scaling Reversible Adhesion in Synthetic and Biological Systems

    NASA Astrophysics Data System (ADS)

    Bartlett, Michael; Irschick, Duncan; Crosby, Alfred

    2013-03-01

    High capacity, easy release polymer adhesives, as demonstrated by a gecko's toe, present unique opportunities for synthetic design. However, without a framework that connects biological and synthetic adhesives from basic nanoscopic features to macroscopic systems, synthetic mimics have failed to perform favorably at large length scales. Starting from an energy balance, we develop a scaling approach to understand unstable interfacial fracture over multiple length scales. The simple theory reveals that reversibly adhesive polymers do not rely upon fibrillar features but require contradicting attributes: maximum compliance normal to the substrate and minimum compliance in the loading direction. We use this counterintuitive criterion to create reversible, easy release adhesives at macroscopic sizes (100 cm2) with unprecedented force capacities on the order of 3000 N. Importantly, we achieve this without fibrillar features, supporting our predictions and emphasizing the importance of subsurface anatomy in biological adhesive systems. Our theory describes adhesive force capacity as a function of material properties and geometry and is supported by over 1000 experiments, spanning both synthetic and biological adhesives, with agreement over 14 orders of magnitude in adhesive force.

  17. Ambient Dried Aerogels

    NASA Technical Reports Server (NTRS)

    Jones, Steven M.; Paik, Jong-Ah

    2013-01-01

    A method has been developed for creating aerogel using normal pressure and ambient temperatures. All spacecraft, satellites, and landers require the use of thermal insulation due to the extreme environments encountered in space and on extraterrestrial bodies. Ambient dried aerogels introduce the possibility of using aerogel as thermal insulation in a wide variety of instances where supercritically dried aerogels cannot be used. More specifically, thermoelectric devices can use ambient dried aerogel, where the advantages are in situ production using the cast-in ability of an aerogel. Previously, aerogels required supercritical conditions (high temperature and high pressure) to be dried. Ambient dried aerogels can be dried at room temperature and pressure. This allows many materials, such as plastics and certain metal alloys that cannot survive supercritical conditions, to be directly immersed in liquid aerogel precursor and then encapsulated in the final, dried aerogel. Additionally, the metalized Mylar films that could not survive the previous methods of making aerogels can survive the ambient drying technique, thus making multilayer insulation (MLI) materials possible. This results in lighter insulation material as well. Because this innovation does not require high-temperature or high-pressure drying, ambient dried aerogels are much less expensive to produce. The equipment needed to conduct supercritical drying costs many tens of thousands of dollars, and has associated running expenses for power, pressurized gasses, and maintenance. The ambient drying process also expands the size of the pieces of aerogel that can be made because a high-temperature, high-pressure system typically has internal dimensions of up to 30 cm in diameter and 60 cm in height. In the case of this innovation, the only limitation on the size of the aerogels produced would be in the ability of the solvent in the wet gel to escape from the gel network.

  18. Dephosphorization when using DRI

    SciTech Connect

    2005-09-21

    The increase in high quality steel production in electric arc furnaces (EAFs) requires the use of scrap substitute materials, such as Direct Reduced Iron (DRI) and Hot Briquetted Iron (HBI). Although DRI and HBI products have lower copper and nickel contents than most scrap materials, they can contain up to ten times more phosphorus. This project, led by Carnegie Mellon University’s Center for Iron and Steelmaking Research, improves the understanding of how phosphorus behaves when DRI and HBI melt.

  19. McMurdo Dry Valleys

    NASA Technical Reports Server (NTRS)

    2002-01-01

    One of the few areas of Antarctica not covered by thousands of meters of ice, the McMurdo Dry Valleys stand out in this satellite image. For a few weeks each summer temperatures are warm enough to melt glacial ice, creating streams that feed freshwater lakes that lie at the bottom of the valleys. Beneath a cap of ice these lakes remains unfrozen year-round, supporting colonies of bacteria and phytoplankton. Over the past 14 years, however, summers have been colder than usual, and the lakes are becoming more and more frozen. If the trend continues, the biological communities they support may go into hibernation. Most of Antarctica has cooled along with the Dry Valleys, in contrast to much of the rest of the Earth, which has warmed over the past 100 years. No one knows if the trend is related to global climate, or just a quirk in the weather. This image was acquired by Landsat 7's Enhanced Thematic Mapper plus (ETM+) instrument on December 18, 1999. For more information, visit: National Public Radio's Mixed Signals from Antarctica Declassified Satellite Imagery of the McMurdo Dry Valleys Image by Robert Simmon, based on data provided by the NASA GSFC Oceans and Ice Branch and the Landsat 7 Science Team

  20. Tuning of cellulose fibres' structure and surface topography: Influence of swelling and various drying procedures.

    PubMed

    Hribernik, Silvo; Stana Kleinschek, Karin; Rihm, Rainer; Ganster, Johannes; Fink, Hans-Peter; Sfiligoj Smole, Majda

    2016-09-01

    Presented study deals with the pre-treatment of cellulose fibres with the aim to activate their surface and to enlarge their pore system, leading to an enhancement of fibres' affinity for subsequent functionalization processes. Swelling of fibres in aqueous solutions of sodium hydroxide opens their fibrillar structure, while freezing and freeze-drying retain this enlargement of the pore system, in contrast with conventional air or elevated temperature drying. Effect of different pre-treatment procedures on fibres' supramolecular structure, enlargement of their pore system, surface topography, zeta potential and mechanical properties was investigated. Degree of enhancement of the pore system depends on the concentration of sodium hydroxide and type of freezing; higher alkali concentrations are more effective, but at the cost of extensive deterioration of mechanical properties. Swelling of fibres in lower concentrations of NaOH, in combination with freeze drying, offers an acceptable compromise between enhancement of the fibres' pore system, changes in surface potential and tensile properties of treated fibres. Design of a suitable regime of swelling and drying of cellulose fibres results in an effective procedure for controlled tuning of their surface topography in combination with an increase of the available internal surface area and pore volume.

  1. Tuning of cellulose fibres' structure and surface topography: Influence of swelling and various drying procedures.

    PubMed

    Hribernik, Silvo; Stana Kleinschek, Karin; Rihm, Rainer; Ganster, Johannes; Fink, Hans-Peter; Sfiligoj Smole, Majda

    2016-09-01

    Presented study deals with the pre-treatment of cellulose fibres with the aim to activate their surface and to enlarge their pore system, leading to an enhancement of fibres' affinity for subsequent functionalization processes. Swelling of fibres in aqueous solutions of sodium hydroxide opens their fibrillar structure, while freezing and freeze-drying retain this enlargement of the pore system, in contrast with conventional air or elevated temperature drying. Effect of different pre-treatment procedures on fibres' supramolecular structure, enlargement of their pore system, surface topography, zeta potential and mechanical properties was investigated. Degree of enhancement of the pore system depends on the concentration of sodium hydroxide and type of freezing; higher alkali concentrations are more effective, but at the cost of extensive deterioration of mechanical properties. Swelling of fibres in lower concentrations of NaOH, in combination with freeze drying, offers an acceptable compromise between enhancement of the fibres' pore system, changes in surface potential and tensile properties of treated fibres. Design of a suitable regime of swelling and drying of cellulose fibres results in an effective procedure for controlled tuning of their surface topography in combination with an increase of the available internal surface area and pore volume. PMID:27185135

  2. To Dry Or Not To Dry

    ERIC Educational Resources Information Center

    Oaks, Audrey E.

    1977-01-01

    Perhaps one of the most frustrating problems which confront many teachers is lack of adequate drying space or facilities for prints, paintings and three-dimensional art activities. Suggests requirements necessary for an adequate storage unit and how to construct one. (Author/RK)

  3. Pinocembrin Protects Human Brain Microvascular Endothelial Cells against Fibrillar Amyloid-β1−40Injury by Suppressing the MAPK/NF-κB Inflammatory Pathways

    PubMed Central

    Li, Jin-ze; Song, Jun-ke; Sun, Jia-lin; Li, Yong-jie; Zhou, Si-bai; Du, Guan-hua

    2014-01-01

    Cerebrovascular accumulation of amyloid-β (Aβ) peptides in Alzheimer's disease (AD) may contribute to disease progression through Aβ-induced microvascular endothelial pathogenesis. Pinocembrin has been shown to have therapeutic effects in AD models. These effects correlate with preservation of microvascular function, but the effect on endothelial cells under Aβ-damaged conditions is unclear. The present study focuses on the in vitro protective effect of pinocembrin on fibrillar Aβ1−40 (fAβ1−40) injured human brain microvascular endothelial cells (hBMECs) and explores potential mechanisms. The results demonstrate that fAβ1−40-induced cytotoxicity in hBMECs can be rescued by pinocembrin treatment. Pinocembrin increases cell viability, reduces the release of LDH, and relieves nuclear condensation. The mechanisms of this reversal from Aβ may be associated with the inhibition of inflammatory response, involving inhibition of MAPK activation, downregulation of phosphor-IKK level, relief of IκBα degradation, blockage of NF-κB p65 nuclear translocation, and reduction of the release of proinflammatory cytokines. Pinocembrin does not show obvious effects on regulating the redox imbalance after exposure to fAβ1−40. Together, the suppression of MAPK and the NF-κB signaling pathways play a significant role in the anti-inflammation of pinocembrin in hBMECs subjected to fAβ1−40. This may serve as a therapeutic agent for BMEC protection in Alzheimer's-related deficits. PMID:25157358

  4. Biphasic calcium phosphate ceramic combined with fibrillar collagen with and without citric acid conditioning in the treatment of periodontal osseous defects.

    PubMed

    Nery, E B; Eslami, A; Van Swol, R L

    1990-03-01

    The purpose of this study is to determine whether the combination of biphasic calcium phosphate ceramic (BCP) and collagen and citric acid root conditioning would promote accelerated new attachment of periodontal tissue to the root surface in dogs. Intrabony defects were surgically produced for each animal and were made chronic for 16 weeks. These defects were assigned to two study treatment and one control group: ceramic-collagen without citric acid (CO-CE); ceramic-collagen with citric acid (CO-CE-CA); and control (surgical debridement and root planing only). Results showed that all groups gained new attachment level as demonstrated both clinically and histometrically. The treatment groups showed a significant mean gain greater than the control (P less than .005), but no significant difference was found between treatment groups. Small areas of ankylosis was also found in both treatments but there was no evidence of active root resorption. It is concluded that the use of combined BCP and fibrillar collagen is beneficial in promoting new attachment of periodontal tissues to the root surface in dogs. Although citric acid root conditioning did as well or better than ceramic and collagen alone, its benefits are still speculative and need further experimentation.

  5. Surface contact and design of fibrillar 'friction pads' in stick insects (Carausius morosus): mechanisms for large friction coefficients and negligible adhesion.

    PubMed

    Labonte, David; Williams, John A; Federle, Walter

    2014-05-01

    Many stick insects and mantophasmids possess tarsal 'heel pads' (euplantulae) covered by arrays of conical, micrometre-sized hairs (acanthae). These pads are used mainly under compression; they respond to load with increasing shear resistance, and show negligible adhesion. Reflected-light microscopy in stick insects (Carausius morosus) revealed that the contact area of 'heel pads' changes with normal load on three hierarchical levels. First, loading brought larger areas of the convex pads into contact. Second, loading increased the density of acanthae in contact. Third, higher loads changed the shape of individual hair contacts gradually from circular (tip contact) to elongated (side contact). The resulting increase in real contact area can explain the load dependence of friction, indicating a constant shear stress between acanthae and substrate. As the euplantula contact area is negligible for small loads (similar to hard materials), but increases sharply with load (resembling soft materials), these pads show high friction coefficients despite little adhesion. This property appears essential for the pads' use in locomotion. Several morphological characteristics of hairy friction pads are in apparent contrast to hairy pads used for adhesion, highlighting key adaptations for both pad types. Our results are relevant for the design of fibrillar structures with high friction coefficients but small adhesion.

  6. Tray Drying of Solids.

    ERIC Educational Resources Information Center

    Afacan, Artin; Masliyah, Jacob

    1984-01-01

    Describes a drying experiment useful in presenting the concept of simultaneous heat and mass transfer. Background information, equipment requirements, experimental procedures, and results are provided. The reasonably good agreement in the calculated rate of drying and that observed experimentally makes students feel confident in applying…

  7. Packaged kiln dried firewood

    SciTech Connect

    Cutrara, A.

    1986-07-01

    A process is described for kiln drying firewood consisting of essentially uniform lengths of split firewood pieces, the process comprising splitting essentially uniform lengths of green tree logs to form firewood pieces, placing the firewood pieces in open mesh bags to provide a plurality of bags of firewood, placing the plurality of bags of green firewood pieces in a kiln drying oven, kiln drying the pieces at temperatures in excess of 150/sup 0/F. by moving heated air over the pieces until the pieces have an overall moisture content ranging from 15% up to 30% by weight, operating the kiln at a temperature below a level which would render the structural characteristics of the bag useless and removing the kiln dried firewood pieces in the plurality of bags from the kiln drying oven.

  8. Dry imaging cameras

    PubMed Central

    Indrajit, IK; Alam, Aftab; Sahni, Hirdesh; Bhatia, Mukul; Sahu, Samaresh

    2011-01-01

    Dry imaging cameras are important hard copy devices in radiology. Using dry imaging camera, multiformat images of digital modalities in radiology are created from a sealed unit of unexposed films. The functioning of a modern dry camera, involves a blend of concurrent processes, in areas of diverse sciences like computers, mechanics, thermal, optics, electricity and radiography. Broadly, hard copy devices are classified as laser and non laser based technology. When compared with the working knowledge and technical awareness of different modalities in radiology, the understanding of a dry imaging camera is often superficial and neglected. To fill this void, this article outlines the key features of a modern dry camera and its important issues that impact radiology workflow. PMID:21799589

  9. Ultrasonic Drying Processing Chamber

    NASA Astrophysics Data System (ADS)

    Acosta, V.; Bon, J.; Riera, E.; Pinto, A.

    The design of a high intensity ultrasonic chamber for drying process was investigated. The acoustic pressure distribution in the ultrasonic drying chamber was simulated solving linear elastic models with attenuation for the acoustic-structure interaction. Together with the government equations, the selection of appropriate boundary conditions, mesh refinement, and configuration parameters of the calculation methods, which is of great importance to simulate adequately the process, were considered. Numerical solution, applying the finite element method (FEM), of acoustic-structure interactions involves to couple structural and fluid elements (with different degrees of freedom), whose solution implies several problems of hardware requirements and software configuration, which were solved. To design the drying chamber, the influence of the directivity of the drying open camera and the staggered reflectors over the acoustic pressure distribution was analyzed. Furthermore, to optimize the influence of the acoustic energy on the drying process, the average value of the acoustic energy distribution in the drying chamber was studied. This would determine the adequate position of the food samples to be dried. For this purpose, the acoustic power absorbed by the samples will be analyzed in later studies.

  10. LASIK and dry eye.

    PubMed

    Toda, Ikuko

    2007-01-01

    Dry eye is one of the most common complications after laser-assisted in situ keratomileusis (LASIK). The clinical signs of post-LASIK dry eye include positive vital staining of ocular surface, decreased tear film breakup time and Schirmer test, reduced corneal sensitivity, and decreased functional visual acuity. The symptoms and signs last at least 1 month after LASIK. Although the mechanisms for developing post-LASIK dry eye are not completely understood, loss of corneal innervation by flap-making may affect the reflex loops of the corneal-lacrimal gland, corneal-blinking, and blinking-meibomian gland, and blinking-meibomian gland, resulting in decreased aqueous and lipid tear secretion and mucin expression. As LASIK enhancement by flap-lifting induces less dry eye symptoms and signs than first surgery, it is suggested that other factors rather than loss of neurotrophic effect may be involved in the mechanisms of post-LASIK dry eye. The treatments of dry eye include artificial tears, topical cyclosporine, hot compress, punctal plugs, and autologous serum eye drops. For patients with severe preoperative dry eye, a combination of punctal plugs and serum eye drops is required to be used before surgery.

  11. Stripping with dry ice

    NASA Astrophysics Data System (ADS)

    Malavallon, Olivier

    1995-04-01

    Mechanical-type stripping using dry ice (solid CO2) consists in blasting particles of dry ice onto the painted surface. This surface can be used alone or in duplex according to type of substrate to be treated. According to operating conditions, three physical mechanisms may be involved when blasting dry ice particles onto a paint system: thermal shock, differential thermal contraction, and mechanical shock. The blast nozzle, nozzle travel speed, blast angle, stripping distance, and compressed air pressure and media flow rate influence the stripping quality and the uniformity and efficiency obtained.

  12. 2. INTERIOR OF SAND DRAINING & DRYING BUILDING WITH DRYING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. INTERIOR OF SAND DRAINING & DRYING BUILDING WITH DRYING BINS TO THE RIGHT, LOOKING SOUTHWEST - Mill "C" Complex, Sand Draining & Drying Building, South of Dee Bennet Road, near Illinois River, Ottawa, La Salle County, IL

  13. Dry Skin (Xerosis)

    MedlinePlus

    ... by medical conditions, such as atopic dermatitis and malnutrition. Dry skin develops due to a decrease in ... Diabetes Hypothyroidism Down syndrome Liver or kidney disease Malnutrition HIV/AIDS Lymphoma Signs and Symptoms The most ...

  14. Freeze drying method

    DOEpatents

    Coppa, Nicholas V.; Stewart, Paul; Renzi, Ernesto

    1999-01-01

    The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser.

  15. Dry electrodes for electrocardiography.

    PubMed

    Meziane, N; Webster, J G; Attari, M; Nimunkar, A J

    2013-09-01

    Patient biopotentials are usually measured with conventional disposable Ag/AgCl electrodes. These electrodes provide excellent signal quality but are irritating for long-term use. Skin preparation is usually required prior to the application of electrodes such as shaving and cleansing with alcohol. To overcome these difficulties, researchers and caregivers seek alternative electrodes that would be acceptable in clinical and research environments. Dry electrodes that operate without gel, adhesive or even skin preparation have been studied for many decades. They are used in research applications, but they have yet to achieve acceptance for medical use. So far, a complete comparison and evaluation of dry electrodes is not well described in the literature. This work compares dry electrodes for biomedical use and physiological research, and reviews some novel systems developed for cardiac monitoring. Lastly, the paper provides suggestions to develop a dry-electrode-based system for mobile and long-term cardiac monitoring applications.

  16. Freeze drying apparatus

    DOEpatents

    Coppa, Nicholas V.; Stewart, Paul; Renzi, Ernesto

    2001-01-01

    The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser.

  17. Pharmaceutical spray freeze drying.

    PubMed

    Wanning, Stefan; Süverkrüp, Richard; Lamprecht, Alf

    2015-07-01

    Pharmaceutical spray-freeze drying (SFD) includes a heterogeneous set of technologies with primary applications in apparent solubility enhancement, pulmonary drug delivery, intradermal ballistic administration and delivery of vaccines to the nasal mucosa. The methods comprise of three steps: droplet generation, freezing and sublimation drying, which can be matched to the requirements given by the dosage form and route of administration. The objectives, various methods and physicochemical and pharmacological outcomes have been reviewed with a scope including related fields of science and technology.

  18. Acoustoconvection Drying of Meat

    NASA Astrophysics Data System (ADS)

    Zhilin, A. A.; Fedorov, A. V.

    2016-03-01

    The dynamics of moisture extraction from meat samples by the acoustoconvection and thermoconvection methods has been investigated. To describe the dynamics of moisture extraction from meat, we propose a simple relaxation model with a relaxation time of 8-10 min in satisfactorily describing experimental data on acoustoconvection drying of meat. For thermoconvection drying the relaxation time is thereby 30 and 45 min for the longitudinal and transverse positions of fibers, respectively.

  19. Congenital Myasthenic Syndrome Type 19 Is Caused by Mutations in COL13A1, Encoding the Atypical Non-fibrillar Collagen Type XIII α1 Chain

    PubMed Central

    Logan, Clare V.; Cossins, Judith; Rodríguez Cruz, Pedro M.; Parry, David A.; Maxwell, Susan; Martínez-Martínez, Pilar; Riepsaame, Joey; Abdelhamed, Zakia A.; Lake, Alice V.R.; Moran, Maria; Robb, Stephanie; Chow, Gabriel; Sewry, Caroline; Hopkins, Philip M.; Sheridan, Eamonn; Jayawant, Sandeep; Palace, Jacqueline; Johnson, Colin A.; Beeson, David

    2015-01-01

    The neuromuscular junction (NMJ) consists of a tripartite synapse with a presynaptic nerve terminal, Schwann cells that ensheathe the terminal bouton, and a highly specialized postsynaptic membrane. Synaptic structural integrity is crucial for efficient signal transmission. Congenital myasthenic syndromes (CMSs) are a heterogeneous group of inherited disorders that result from impaired neuromuscular transmission, caused by mutations in genes encoding proteins that are involved in synaptic transmission and in forming and maintaining the structural integrity of NMJs. To identify further causes of CMSs, we performed whole-exome sequencing (WES) in families without an identified mutation in known CMS-associated genes. In two families affected by a previously undefined CMS, we identified homozygous loss-of-function mutations in COL13A1, which encodes the alpha chain of an atypical non-fibrillar collagen with a single transmembrane domain. COL13A1 localized to the human muscle motor endplate. Using CRISPR-Cas9 genome editing, modeling of the COL13A1 c.1171delG (p.Leu392Sfs∗71) frameshift mutation in the C2C12 cell line reduced acetylcholine receptor (AChR) clustering during myotube differentiation. This highlights the crucial role of collagen XIII in the formation and maintenance of the NMJ. Our results therefore delineate a myasthenic disorder that is caused by loss-of-function mutations in COL13A1, encoding a protein involved in organization of the NMJ, and emphasize the importance of appropriate symptomatic treatment for these individuals. PMID:26626625

  20. Congenital Myasthenic Syndrome Type 19 Is Caused by Mutations in COL13A1, Encoding the Atypical Non-fibrillar Collagen Type XIII α1 Chain.

    PubMed

    Logan, Clare V; Cossins, Judith; Rodríguez Cruz, Pedro M; Parry, David A; Maxwell, Susan; Martínez-Martínez, Pilar; Riepsaame, Joey; Abdelhamed, Zakia A; Lake, Alice V R; Moran, Maria; Robb, Stephanie; Chow, Gabriel; Sewry, Caroline; Hopkins, Philip M; Sheridan, Eamonn; Jayawant, Sandeep; Palace, Jacqueline; Johnson, Colin A; Beeson, David

    2015-12-01

    The neuromuscular junction (NMJ) consists of a tripartite synapse with a presynaptic nerve terminal, Schwann cells that ensheathe the terminal bouton, and a highly specialized postsynaptic membrane. Synaptic structural integrity is crucial for efficient signal transmission. Congenital myasthenic syndromes (CMSs) are a heterogeneous group of inherited disorders that result from impaired neuromuscular transmission, caused by mutations in genes encoding proteins that are involved in synaptic transmission and in forming and maintaining the structural integrity of NMJs. To identify further causes of CMSs, we performed whole-exome sequencing (WES) in families without an identified mutation in known CMS-associated genes. In two families affected by a previously undefined CMS, we identified homozygous loss-of-function mutations in COL13A1, which encodes the alpha chain of an atypical non-fibrillar collagen with a single transmembrane domain. COL13A1 localized to the human muscle motor endplate. Using CRISPR-Cas9 genome editing, modeling of the COL13A1 c.1171delG (p.Leu392Sfs(∗)71) frameshift mutation in the C2C12 cell line reduced acetylcholine receptor (AChR) clustering during myotube differentiation. This highlights the crucial role of collagen XIII in the formation and maintenance of the NMJ. Our results therefore delineate a myasthenic disorder that is caused by loss-of-function mutations in COL13A1, encoding a protein involved in organization of the NMJ, and emphasize the importance of appropriate symptomatic treatment for these individuals. PMID:26626625

  1. Electro-dry-adhesion.

    PubMed

    Krahn, Jeffrey; Menon, Carlo

    2012-03-27

    This work presents novel conductive bioinspired dry adhesives with mushroom caps that enable the use of a synergistic combination of electrostatic and van der Waals forces (electro-dry-adhesion). An increase in shear adhesion bond strength of up to 2046% on a wide range of materials is measured when a maximum electrical field of 36.4 V μm(-1) is applied. A suction effect, due to the shape of the dry adhesive fibers, on overall adhesion was not noted for electro-dry-adhesives when testing was performed at both atmospheric and reduced pressure. Utilization of electrostatics to apply a preloading force to dry adhesive fiber arrays allows increased adhesion even after electrostatic force generation has been halted by ensuring the close contact necessary for van der Waals forces to be effective. A comparison is made between self-preloading of the electro-dry-adhesives and the direct application of a normal preloading pressure resulting in nearly the same shear bond strength with an applied voltage of 3.33 kV on the same sample.

  2. Electro-dry-adhesion.

    PubMed

    Krahn, Jeffrey; Menon, Carlo

    2012-03-27

    This work presents novel conductive bioinspired dry adhesives with mushroom caps that enable the use of a synergistic combination of electrostatic and van der Waals forces (electro-dry-adhesion). An increase in shear adhesion bond strength of up to 2046% on a wide range of materials is measured when a maximum electrical field of 36.4 V μm(-1) is applied. A suction effect, due to the shape of the dry adhesive fibers, on overall adhesion was not noted for electro-dry-adhesives when testing was performed at both atmospheric and reduced pressure. Utilization of electrostatics to apply a preloading force to dry adhesive fiber arrays allows increased adhesion even after electrostatic force generation has been halted by ensuring the close contact necessary for van der Waals forces to be effective. A comparison is made between self-preloading of the electro-dry-adhesives and the direct application of a normal preloading pressure resulting in nearly the same shear bond strength with an applied voltage of 3.33 kV on the same sample. PMID:22397643

  3. Advanced gecko-foot-mimetic dry adhesives based on carbon nanotubes.

    PubMed

    Hu, Shihao; Xia, Zhenhai; Dai, Liming

    2013-01-21

    Geckos can run freely on vertical walls and even ceilings. Recent studies have discovered that gecko's extraordinary climbing ability comes from a remarkable design of nature with nanoscale beta-keratin elastic hairs on their feet and toes, which collectively generate sufficiently strong van der Waals force to hold the animal onto an opposing surface while at the same time disengaging at will. Vertically aligned carbon nanotube (VA-CNT) arrays, resembling gecko's adhesive foot hairs with additional superior mechanical, chemical and electrical properties, have been demonstrated to be a promising candidate for advanced fibrillar dry adhesives. The VA-CNT arrays with tailor-made hierarchical structures can be patterned and/or transferred onto various flexible substrates, including responsive polymers. This, together with recent advances in nanofabrication techniques, could offer 'smart' dry adhesives for various potential applications, even where traditional adhesives cannot be used. A detailed understanding of the underlying mechanisms governing the material properties and adhesion performances is critical to the design and fabrication of gecko inspired CNT dry adhesives of practical significance. In this feature article, we present an overview of recent progress in both fundamental and applied frontiers for the development of CNT-based adhesives by summarizing important studies in this exciting field, including our own work.

  4. Advanced gecko-foot-mimetic dry adhesives based on carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Hu, Shihao; Xia, Zhenhai; Dai, Liming

    2012-12-01

    Geckos can run freely on vertical walls and even ceilings. Recent studies have discovered that gecko's extraordinary climbing ability comes from a remarkable design of nature with nanoscale beta-keratin elastic hairs on their feet and toes, which collectively generate sufficiently strong van der Waals force to hold the animal onto an opposing surface while at the same time disengaging at will. Vertically aligned carbon nanotube (VA-CNT) arrays, resembling gecko's adhesive foot hairs with additional superior mechanical, chemical and electrical properties, have been demonstrated to be a promising candidate for advanced fibrillar dry adhesives. The VA-CNT arrays with tailor-made hierarchical structures can be patterned and/or transferred onto various flexible substrates, including responsive polymers. This, together with recent advances in nanofabrication techniques, could offer `smart' dry adhesives for various potential applications, even where traditional adhesives cannot be used. A detailed understanding of the underlying mechanisms governing the material properties and adhesion performances is critical to the design and fabrication of gecko inspired CNT dry adhesives of practical significance. In this feature article, we present an overview of recent progress in both fundamental and applied frontiers for the development of CNT-based adhesives by summarizing important studies in this exciting field, including our own work.

  5. Biological Threats

    MedlinePlus

    ... Thunderstorms & Lightning Tornadoes Tsunamis Volcanoes Wildfires Main Content Biological Threats Biological agents are organisms or toxins that ... Centers for Disease Control and Prevention . Before a Biological Threat Unlike an explosion, a biological attack may ...

  6. Dry Dock No. 3. View of head of Dry Dock ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Dry Dock No. 3. View of head of Dry Dock with stair to right of shot. View facing west - U.S. Naval Base, Pearl Harbor, Dry Dock No. 3, On northern shoreline of shipyard, west of Dry Dock Nos. 1 & 2, near the intersection of Avenue G and Sixth Street, Pearl City, Honolulu County, HI

  7. Laser polarization fluorescence of the networks of optically anisotropic biological crystals

    NASA Astrophysics Data System (ADS)

    Ushenko, Y. A.; Dubolazov, A. V.; Angelsky, A. P.; Sidor, M. I.; Bodnar, G. B.; Koval, G.; Zabolotna, N. I.; Smolarz, A.; Junisbekov, M. Sh.

    2013-01-01

    The present work is devoted to investigation of mechanisms of optical anisotropy of biological tissues polycrystalline networks and laser polarization fluorescence. The model of complex optical anisotropy, which takes into account both linear and circular birefringence, as well as linear and circular dichroism of fibrillar networks of histological sections of women reproductive sphere is proposed. The data of statistical, correlation and fractal processing of coordinate distributions of laser polarization fluorescence is provided. The technique of azimuthally invariant Mueller-matrix mapping of laser polarization fluorescence of protein networks in the tasks of differentiation of benign and malignant tumors of uterus wall is elaborated.

  8. Reconstructing Habitable Environments on a Late Noachian Icy Mars: Causes, Frequencies and Durations of Melting, Fate of Meltwater, and Biological Insights from the McMurdo Dry Valleys. James W. Head, Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912 USA

    NASA Astrophysics Data System (ADS)

    Head, J. W., III

    2014-12-01

    Recent global climate models for Late Noachian Mars have underlined the difficulty of producing and sustaining a "warm and wet" early Mars, suggesting instead a cold and icy late Noachian climate dominated by stable ice sheets in the highlands and a horizontally stratified hydrological system. If Late Noachian Mars was "cold and icy", how can one explain the origin and distribution of the extensive valley networks and abundant open basin lakes? Could periodic or catastrophic melting of highland ice sheets produce the observed features? Are there areas where the horizontally stratified hydrological system is breached to enable communication with the groundwater system below? Would such scenarios lead to habitable environments? Analogs of aqueous environments and biological settings from the McMurdo Dry Valleys are combined with assessment of several top-down and bottom-up melting mechanisms for the Late Noachian Icy Highlands to outline predictions for the location and duration of potential habitable environments. Explored are 1) the volumes of ice available and the possibility that ice distribution and thickness are "supply-limited", 2) the areal distribution of available ice, 3) the total amount of meltwater necessary to account for the observed features, 4) the predicted duration of aqueous production and longevity of aqueous environments under different melting scenarios, 5) the predicted geomorphic features formed by these mechanisms, and 6) similarities of these predicted features to the distribution and morphologic/morphometric characteristics of observed valley networks and open-basin lakes. The results are interpreted in the context of known habitable environments in the Mars-like hyperarid, hypothermal McMurdo Dry Valleys, comparing and assessing the locations of meltwater production and biological activity, the stratification of the hydrological system, and communication with the groundwater system below. Predictions are made for remote sensing signatures

  9. Magnetically responsive dry fluids.

    PubMed

    Sousa, Filipa L; Bustamante, Rodney; Millán, Angel; Palacio, Fernando; Trindade, Tito; Silva, Nuno J O

    2013-08-21

    Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid. PMID:23831769

  10. Current Approach to Dry Eye Disease.

    PubMed

    Valim, Valéria; Trevisani, Virginia Fernandes Moça; de Sousa, Jacqueline Martins; Vilela, Verônica Silva; Belfort, Rubens

    2015-12-01

    Dry eye disease (DED) is a multifactorial disease of the tears and ocular surface that causes tear film instability with potential damage to the ocular surface. The prevalence of dry eye in the world population ranges from 6 to 34 %. It is more common in those aged over 50, and affects mainly women. Since the introduction of the Schirmer's test in 1903, other tests have been developed to evaluate dry eye, such as biomicroscopy, the tear film breakup time (BUT), vital dyes (lissamine green and rose bengal), fluorescein, leaf fern test, corneal sensitivity test, conjunctiva impression cytology, optical coherence tomography (OCT), and tear osmolarity measurement. Although there is no gold standard, it is advisable to combine at least two tests. Strategies for treating DED have recently been modified and include patient education, tear substitute, corticosteroids, secretagogues, fatty acids, immunomodulators, occlusion of lacrimal puncta surgery and, tarsorrhaphy. Biological therapy and new topical immunomodulators such as tacrolimus, tofacitinib and IL-1 receptor inhibitor are being tested. In this review, the evaluation tests for dry eye are compared and the main studies on treatment are presented, with emphasis on studies in patients with Sjögren's syndrome. The authors propose an approach for the management of dry eye. PMID:25081064

  11. Magnetically responsive dry fluids

    NASA Astrophysics Data System (ADS)

    Sousa, Filipa L.; Bustamante, Rodney; Millán, Angel; Palacio, Fernando; Trindade, Tito; Silva, Nuno J. O.

    2013-07-01

    Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid.Ferrofluids and dry magnetic particles are two separate classes of magnetic materials with specific niche applications, mainly due to their distinct viscosity and interparticle distances. For practical applications, the stability of these two properties is highly desirable but hard to achieve. Conceptually, a possible solution to this problem would be encapsulating the magnetic particles but keeping them free to rotate inside a capsule with constant interparticle distances and thus shielded from changes in the viscosity of the surrounding media. Here we present an example of such materials by the encapsulation of magnetic ferrofluids into highly hydrophobic silica, leading to the formation of dry ferrofluids, i.e., a material behaving macroscopically as a dry powder but locally as a ferrofluid where magnetic nanoparticles are free to rotate in the liquid. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr01784b

  12. [Towards a structuring fibrillar ontology].

    PubMed

    Guimberteau, J-C

    2012-10-01

    Over previous decades and centuries, the difficulty encountered in the manner in which the tissue of our bodies is organised, and structured, is clearly explained by the impossibility of exploring it in detail. Since the creation of the microscope, the perception of the basic unity, which is the cell, has been essential in understanding the functioning of reproduction and of transmission, but has not been able to explain the notion of form; since the cells are not everywhere and are not distributed in an apparently balanced manner. The problems that remain are those of form and volume and also of connection. The concept of multifibrillar architecture, shaping the interfibrillar microvolumes in space, represents a solution to all these questions. The architectural structures revealed, made up of fibres, fibrils and microfibrils, from the mesoscopic to the microscopic level, provide the concept of a living form with structural rationalism that permits the association of psychochemical molecular biodynamics and quantum physics: the form can thus be described and interpreted, and a true structural ontology is elaborated from a basic functional unity, which is the microvacuole, the intra and interfibrillar volume of the fractal organisation, and the chaotic distribution. Naturally, new, less linear, less conclusive, and less specific concepts will be implied by this ontology, leading one to believe that the emergence of life takes place under submission to forces that the original form will have imposed and oriented the adaptive finality.

  13. [Towards a structuring fibrillar ontology].

    PubMed

    Guimberteau, J-C

    2012-10-01

    Over previous decades and centuries, the difficulty encountered in the manner in which the tissue of our bodies is organised, and structured, is clearly explained by the impossibility of exploring it in detail. Since the creation of the microscope, the perception of the basic unity, which is the cell, has been essential in understanding the functioning of reproduction and of transmission, but has not been able to explain the notion of form; since the cells are not everywhere and are not distributed in an apparently balanced manner. The problems that remain are those of form and volume and also of connection. The concept of multifibrillar architecture, shaping the interfibrillar microvolumes in space, represents a solution to all these questions. The architectural structures revealed, made up of fibres, fibrils and microfibrils, from the mesoscopic to the microscopic level, provide the concept of a living form with structural rationalism that permits the association of psychochemical molecular biodynamics and quantum physics: the form can thus be described and interpreted, and a true structural ontology is elaborated from a basic functional unity, which is the microvacuole, the intra and interfibrillar volume of the fractal organisation, and the chaotic distribution. Naturally, new, less linear, less conclusive, and less specific concepts will be implied by this ontology, leading one to believe that the emergence of life takes place under submission to forces that the original form will have imposed and oriented the adaptive finality. PMID:22921289

  14. Common interruptions in the repeating tripeptide sequence of non-fibrillar collagens: sequence analysis and structural studies on triple-helix peptide models.

    PubMed

    Thiagarajan, Geetha; Li, Yingjie; Mohs, Angela; Strafaci, Christopher; Popiel, Magdalena; Baum, Jean; Brodsky, Barbara

    2008-02-22

    Interruptions in the repeating (Gly-X1-X2)(n) amino acid sequence pattern are found in the triple-helix domains of all non-fibrillar collagens, and perturbations to the triple-helix at such sites are likely to play a role in collagen higher-order structure and function. This study defines the sequence features and structural consequences of the most common interruption, where one residue is missing from the tripeptide pattern, Gly-X1-X2-Gly-AA(1)-Gly-X1-X2, designated G1G interruptions. Residues found within G1G interruptions are predominantly hydrophobic (70%), followed by a significant amount of charged residues (16%), and the Gly-X1-X2 triplets flanking the interruption are atypical. Studies on peptide models indicate the degree of destabilization is much greater when Pro is in the interruption, GP, than when hydrophobic residues (GF, GY) are present, and a rigid Gly-Pro-Hyp tripeptide adjacent to the interruption leads to greater destabilization than a flexible Gly-Ala-Ala sequence. Modeling based on NMR data indicates the Phe residue within a GF interruption is located on the outside of the triple helix. The G1G interruptions resemble a previously studied collagen interruption GPOGAAVMGPO, designated G4G-type, in that both are destabilizing, but allow continuation of rod-like triple helices and maintenance of the single residue stagger throughout the imperfection, with a loss of axial register of the superhelix on both sides. Both kinds of interruptions result in a highly localized perturbation in hydrogen bonding and dihedral angles, but the hydrophobic residue of a G4G interruption packs near the central axis of the superhelix, while the hydrophobic residue of a G1G interruption is located on the triple-helix surface. The different structural consequences of G1G and G4G interruptions in the repeating tripeptide sequence pattern suggest a physical basis for their differential susceptibility to matrix metalloproteinases in type X collagen.

  15. Drying drops of blood

    NASA Astrophysics Data System (ADS)

    Brutin, David; Sobac, Benjamin; Loquet, Boris; Sampol, José.

    2010-11-01

    The drying of a drop of human blood is fascinating by the complexity of the physical mechanisms that occur as well as the beauty of the phenomenon which has never been previously evidenced in the literature. The final stage of full blood evaporation reveals for a healthy person the same regular pattern with a good reproducibility. Other tests on anemia and hyperlipidemic persons were performed and presented different patterns. By means of digital camera, the influence of the motion of red blood cells (RBCs) which represent about 50% of the blood volume, is revealed as well as its consequences on the final stages of drying. The mechanisms which lead to the final pattern of dried blood drops are presented and explained on the basis of fluid and solid mechanics in conjunction with the principles of hematology. Our group is the first to evidence that the specific regular patterns characteristic of a healthy individual do not appear in a dried drop of blood from a person with blood disease. Blood is a complex colloidal suspension for which the flow motion is clearly non-Newtonian. When drops of blood evaporate, all the colloids are carried by the flow motion inside the drop and interact.

  16. Quality of dry ginger (Zingiber officinale) by different drying methods.

    PubMed

    E, Jayashree; R, Visvanathan; T, John Zachariah

    2014-11-01

    Ginger rhizomes sliced to various lengths of 5, 10, 15, 20, 30, 40, 50 mm and whole rhizomes were dried from an initial moisture content of 81.3 % to final moisture content of less than 10 % by various drying methods like sun drying, solar tunnel drying and cabinet tray drying at temperatures of 50, 55, 60 and 65 °C. Slicing of ginger rhizomes significantly reduced the drying time of ginger in all the drying methods. It was observed that drying of whole ginger rhizomes under sun took the maximum time (9 days) followed by solar tunnel drying (8 days). Significant reduction in essential oil and oleoresin content of dry ginger was found as the slice length decreased. The important constituents of ginger essential oil like zingiberene, limonene, linalool, geraniol and nerolidol as determined using a gas chromatography was also found to decrease during slicing and as the drying temperature increased. The pungency constituents in the oleoresin of ginger like total gingerols and total shogoals as determined using a reverse phase high performance liquid chromatography also showed a decreasing trend on slicing and with the increase in drying temperature. It was observed from the drying studies that whole ginger rhizomes dried under sun drying or in a solar tunnel drier retained the maximum essential oil (13.9 mg/g) and oleoresin content (45.2 mg/g) of dry ginger. In mechanical drying, the drying temperature of 60 °C was considered optimum however there was about 12.2 % loss in essential oil at this temperature.

  17. Toxicological evaluation of dry ice expanded tobacco.

    PubMed

    Theophilus, Eugenia H; Poindexter, Dale B; Meckley, Daniel R; Bombick, Betsy R; Borgerding, Michael F; Higuchi, Mark A; Ayres, Paul H; Morton, Michael J; Mosberg, Arnold T; Swauger, James E

    2003-11-30

    A tiered testing strategy has been developed to evaluate the potential of tobacco processes, ingredients, or technological developments to change the biological activity resulting from burning tobacco. The strategy is based on comparative chemical and biological testing. Dry ice expanded tobacco (DIET) is an example of a common tobacco expansion process currently used in the manufacture of cigarettes to increase tobacco filling capacity. As part of the toxicological evaluation of DIET, test cigarettes containing DIET were compared with control cigarettes containing tobacco expanded with a traditional expansion agent (Freon-11, also known as trichlorofluoromethane). Testing included mainstream cigarette smoke chemistry studies, genotoxicity studies (Ames and sister chromatid exchange, SCE), a 13-week inhalation study in Sprague-Dawley rats, and a 30-week dermal tumor promotion study in SENCAR mice. Cigarettes containing DIET or Freon-11 expanded tobacco were similar in biological activity. PMID:14581163

  18. Dry etching of metallization

    NASA Technical Reports Server (NTRS)

    Bollinger, D.

    1983-01-01

    The production dry etch processes are reviewed from the perspective of microelectronic fabrication applications. The major dry etch processes used in the fabrication of microelectronic devices can be divided into two categories - plasma processes in which samples are directly exposed to an electrical discharge, and ion beam processes in which samples are etched by a beam of ions extracted from a discharge. The plasma etch processes can be distinguished by the degree to which ion bombardment contributes to the etch process. This, in turn is related to capability for anisotropic etching. Reactive Ion Etching (RIE) and Ion Beam Etching are of most interest for etching of thin film metals. RIE is generally considered the best process for large volume, anisotropic aluminum etching.

  19. Dry eye syndrome.

    PubMed

    Javadi, Mohammad-Ali; Feizi, Sepehr

    2011-07-01

    Our understanding of keratoconjunctivitis sicca (KCS), also known as dry eye syndrome, has been changed over recent years. Until lately, the condition was thought to be merely due to aqueous tear insufficiency. Today, it is understood that KCS is a multifactorial disorder due to inflammation of the ocular surface and lacrimal gland, neurotrophic deficiency and meibomian gland dysfunction. This change in paradigm has led to the development of new and more effective medications.

  20. Ultrasonic Clothes Drying Technology

    ScienceCinema

    Patel, Viral; Momen, Ayyoub

    2016-07-12

    Oak Ridge National Laboratory researchers Ayyoub Momen and Viral Patel demonstrate a direct contact ultrasonic clothes dryer under development by ORNL in collaboration with General Electric (GE) Appliances. This novel approach uses high-frequency mechanical vibrations instead of heat to extract moisture as cold mist, dramatically reducing drying time and energy use. Funding for this project was competitively awarded by DOE’s Building Technologies Office in 2014.

  1. Drying of fiber webs

    DOEpatents

    Warren, David W.

    1997-01-01

    A process and an apparatus for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquified eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten media does not appreciately stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers.

  2. Drying of fiber webs

    DOEpatents

    Warren, D.W.

    1997-04-15

    A process and an apparatus are disclosed for high-intensity drying of fiber webs or sheets, such as newsprint, printing and writing papers, packaging paper, and paperboard or linerboard, as they are formed on a paper machine. The invention uses direct contact between the wet fiber web or sheet and various molten heat transfer fluids, such as liquefied eutectic metal alloys, to impart heat at high rates over prolonged durations, in order to achieve ambient boiling of moisture contained within the web. The molten fluid contact process causes steam vapor to emanate from the web surface, without dilution by ambient air; and it is differentiated from the evaporative drying techniques of the prior industrial art, which depend on the uses of steam-heated cylinders to supply heat to the paper web surface, and ambient air to carry away moisture, which is evaporated from the web surface. Contact between the wet fiber web and the molten fluid can be accomplished either by submersing the web within a molten bath or by coating the surface of the web with the molten media. Because of the high interfacial surface tension between the molten media and the cellulose fiber comprising the paper web, the molten media does not appreciatively stick to the paper after it is dried. Steam generated from the paper web is collected and condensed without dilution by ambient air to allow heat recovery at significantly higher temperature levels than attainable in evaporative dryers. 6 figs.

  3. Automatic dry eye detection.

    PubMed

    Yedidya, Tamir; Hartley, Richard; Guillon, Jean-Pierre; Kanagasingam, Yogesan

    2007-01-01

    Dry Eye Syndrome is a common disease in the western world, with effects from uncomfortable itchiness to permanent damage to the ocular surface. Nevertheless, there is still no objective test that provides reliable results. We have developed a new method for the automated detection of dry areas in videos taken after instilling fluorescein in the tear film. The method consists of a multi-step algorithm to first locate the iris in each image, then align the images and finally analyze the aligned sequence in order to find the regions of interest. Since the fluorescein spreads on the ocular surface of the eye the edges of the iris are fuzzy making the detection of the iris challenging. We use RANSAC to first detect the upper and lower eyelids and then the iris. Then we align the images by finding differences in intensities at different scales and using a least squares optimization method (Levenberg-Marquardt), to overcome the movement of the iris and the camera. The method has been tested on videos taken from different patients. It is demonstrated to find the dry areas accurately and to provide a measure of the extent of the disease. PMID:18051131

  4. Dry dock no. 4. Service Building between dry docks 4 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Dry dock no. 4. Service Building between dry docks 4 and 5. Floor plans (Navy Yard Public Works Office 1941). In files of Cushman & Wakefield, building 501. Philadelphia Naval Business Center. - Naval Base Philadelphia-Philadelphia Naval Shipyard, Service Building, Dry Docks No. 4 & 5, League Island, Philadelphia, Philadelphia County, PA

  5. [Ocular surface investigations in dry eye].

    PubMed

    Labbé, A; Brignole-Baudouin, F; Baudouin, C

    2007-01-01

    Dry eye is a complex clinicopathological entity involving tear film, lacrimal glands, eyelids, and a wide spectrum of ocular surface cells, including epithelial, inflammatory, immune, and goblet cells. From the tightly regulated lacrimal film functions and structure, a large variety of investigations have been developed, including tear meniscus measurements, fluorophotometry, meibometry, interference pattern analysis, evaporation rate, tear osmolarity, and thermography. Dry eye conditions also interfere with the ocular surface, causing corneal irregularities that may be explored using the techniques of videokeratography and in vivo confocal microscopy, or optical impairment, as confirmed by aberrometry. At the level of ocular surface cells, impression cytology remains a standard for assessing cell alterations. It has greatly benefited from new confocal microscopy, molecular biology, and flow cytometry techniques. Biological assessment of tear proteins or other mediators is also useful. Major limits should be acknowledged, however, such as technical issues in tear film collection, especially in dry eyes, and the lack of standardization of most measurements. Tear osmolarity, electrophoresis, and dosage of normal tear proteins, such as lysozyme or lactoferrin, remain the most useful tests. Finally, some extraocular explorations such as accessory gland biopsy or serum antinuclear antibody dosage may be useful for assessing the diagnosis of Sjögren's syndrome.

  6. Electron transfer in biology

    NASA Astrophysics Data System (ADS)

    Williams, R. J. P.

    Electron transfer is one of the key reactions of biology not just in catalysis of oxidation/reduction reactions but in the conversion of sources of energy such as light to usable form for chemical transformations. There are then two intriguing problems. What is the nature of the matrix in which electrons flow in a biological cell after the initial charge separation due for example to the absorption of light. Here we are examining biological structures similar to man's electronic wires and the construction must be of low resistance in what are apparently insulators - organic polymers. It has been found that the electronic conduction system is largely made from metallo-proteins associated with lipid membranes. We understand much about these biological wires today. The second problem concerns the conversion of the energy captured from the light into usable chemical form. The major synthetic step in the production of biological polymers, including proteins, DNA, RNA, polysaccharides and fats, is condensation, i.e. the removal of water in the formation of amides, esters and so on. Now these condensation reactions are driven in biology by using a drying agent in water, namely the anhydride, pyrophosphate, in a special compound ATP, adenosine triphosphate. The central problem is to discover exactly how the flow of electrons can be related to the synthesis of (bound) pyrophosphate. (In a thermodynamic sense pyrophosphate is a water soluble kinetically stable drying agent comparable with solid P2O5.) In the biological systems the connection between these different classes of reaction, electron transfer and condensation, is known to be via the production of an energized gradient of protons across the biological membrane which arises from the flow of electrons across the same membrane in the electron transport wires of biology. However we do not understand thoroughly the steps which lead from electron flow in a membrane to proton gradients in that membrane, i.e. electron

  7. Simple Solutions for Dry Eye

    MedlinePlus

    ... are more concentrated in the tear film of dry eye patients. In hot weather, sleep with the windows shut and keep cool with air conditioning. • Dry eye patients often develop or aggravate allergies. An ...

  8. Biological Technicians

    MedlinePlus

    ... Biological technicians typically need a bachelor’s degree in biology or a closely related field. It is important ... Biological technicians typically need a bachelor’s degree in biology or a closely related field. It is important ...

  9. LASER METHODS IN BIOLOGY: Optical anisotropy of fibrous biological tissues: analysis of the influence of structural properties

    NASA Astrophysics Data System (ADS)

    Zimnyakov, D. A.; Sinichkin, Yu P.; Ushakova, O. V.

    2007-08-01

    The results of theoretical analysis of the optical anisotropy of multiply scattering fibrillar biological tissues based on the model of an effective anisotropic medium are compared with the experimental in vivo birefringence data for the rat derma obtained earlier in spectral polarisation measurements of rat skin samples in the visible region. The disordered system of parallel dielectric cylinders embedded into an isotropic dielectric medium was considered as a model medium. Simulations were performed taking into account the influence of a partial mutual disordering of the bundles of collagen and elastin fibres in derma on birefringence in samples. The theoretical optical anisotropy averaged over the spectral interval 550-650 nm for the model medium with parameters corresponding to the structural parameters of derma is in good agreement with the results of spectral polarisation measurements of skin samples in the corresponding wavelength range.

  10. Desiccant drying of gas pipelines

    SciTech Connect

    LaCasse, G.A.; Ingvordsen, T.

    1988-09-01

    Prevention of hydrates buildup and corrosion in gas pipelines after hydrostatic testing is increasingly important to those in the gas industry. This paper outlines a dry air method used in Denmark for drying gas pipelines. The psychrometric principles, drying method, and humidity measurements are described.

  11. Non isothermal drying process optimisation - Drying of clay tiles

    NASA Astrophysics Data System (ADS)

    Vasić, M.; Radojević, Z.

    2015-11-01

    In our previous studies we have developed a model for determination of the variable effective diffusivity and identification of the exact transition points between possible drying mechanisms. The next goal was to develop a drying regime which could in advance characterize the real non isothermal process of drying clay tiles. In order to do this four isothermal experiments were recorded. Temperature and humidity were maintained at 350C / 75%; 450C / 70%; 450C / 60% and 500C / 60%; respectively in each experiment. All experimentally collected data were analyzed and the exact transition points between possible drying mechanisms were detected. Characteristic drying period (time) for each isothermal drying mechanism was also detected. The real, non-isothermal drying process was approximated by 5 segments. In each of these segments approximately isothermal drying condition were maintained. Temperature and humidity of the drying air, in the first four segments, was maintained on the same level as in recorded isothermal experiments while in the fifth segment, it were maintained at 700C / 40%. The duration of the first four segments were calculated from the diagrams Deff - t respectively for each experiment. The clay tile in experiment five was dried without cracking using the proposed non isothermal drying regime.

  12. Electrohydrodynamic Drying of Carrot Slices

    PubMed Central

    Ding, Changjiang; Lu, Jun; Song, Zhiqing

    2015-01-01

    Carrots have one of the highest levels of carotene, and they are rich in vitamins, fiber and minerals. However, since fresh carrots wilt rapidly after harvest under inappropriate storage conditions, drying has been used to improve their shelf life and retain nutritional quality. Therefore, to further investigate the potential of this method, carrot slices were dried in an EHD system in order to study the effect of different voltages on drying rate. As measures of quality, carotene content and rehydration ratio were, respectively, compared against the conventional oven drying regime. Carotene, the main component of the dried carrot, and rehydration characteristics of the dried product can both indicate quality by physical and chemical changes during the drying process. Mathematical modeling and simulation of drying curves were also performed, using root mean square error, reduced mean square of the deviation and modeling efficiency as the primary criteria to select the equation that best accounts for the variation in the drying curves of the dried samples. Theoretically, the Page model was best suited for describing the drying rate curve of carrot slices at 10kV to 30kV. Experimentally, the drying rate of carrots was notably greater in the EHD system when compared to control, and quality, as determined by carotene content and rehydration ratio, was also improved when compared to oven drying. Therefore, this work presents a facile and effective strategy for experimentally and theoretically determining the drying properties of carrots, and, as a result, it provides deeper insight into the industrial potential of the EHD drying technique. PMID:25874695

  13. Method of drying articles

    DOEpatents

    Janney, Mark A.; Kiggans, Jr., James O.

    1999-01-01

    A method of drying a green particulate article includes the steps of: a. Providing a green article which includes a particulate material and a pore phase material, the pore phase material including a solvent; and b. contacting the green article with a liquid desiccant for a period of time sufficient to remove at least a portion of the solvent from the green article, the pore phase material acting as a semipermeable barrier to allow the solvent to be sorbed into the liquid desiccant, the pore phase material substantially preventing the liquid desiccant from entering the pores.

  14. Method of drying articles

    DOEpatents

    Janney, M.A.; Kiggans, J.O. Jr.

    1999-03-23

    A method of drying a green particulate article includes the steps of: (a) Providing a green article which includes a particulate material and a pore phase material, the pore phase material including a solvent; and (b) contacting the green article with a liquid desiccant for a period of time sufficient to remove at least a portion of the solvent from the green article, the pore phase material acting as a semipermeable barrier to allow the solvent to be sorbed into the liquid desiccant, the pore phase material substantially preventing the liquid desiccant from entering the pores. 3 figs.

  15. Advances in drying: Volume 4

    SciTech Connect

    Mujumdar, A.S.

    1987-01-01

    Topics covered in this volume include recent thoughts in modeling of drying phenomena, use of computers in rational design of drying particulates, recent advances in drying of wood, and heat/mass transfer phenomena in drying of solids. As the readers will no doubt notice, special effort is made to ensure the truly international nature of the contents of this serial publication. As existing knowledge on drying and dryers becomes more widely and readily accessible, it is expected that more and more dryers will be designed rationally rather than built solely with the benefit of empiricism.

  16. Dry reforming of hydrocarbon feedstocks

    SciTech Connect

    Shah, Yatish T.; Gardner, Todd H.

    2014-09-25

    Developments in catalyst technology for the dry reforming of hydrocarbon feedstocks are reviewed for methane, higher hydrocarbons and alcohols. Thermodynamics, mechanisms and the kinetics of dry reforming are also reviewed. The literature on Ni catalysts, bi-metallic Ni catalysts and the role of promoters on Ni catalysts is critically evaluated. The use of noble and transitional metal catalysts for dry reforming is discussed. The application of solid oxide and metal carbide catalysts to dry reforming is also evaluated. Finally, various mechanisms for catalyst deactivation are assessed. This review also examines the various process related issues associated with dry reforming such as its application and heat optimization. Novel approaches such as supercritical dry reforming and microwave assisted dry reforming are briefly expanded upon.

  17. Deep layer malt drying modelling

    SciTech Connect

    Lopez, A.; Virseda, P.; Martinez, G.; Llorca, M.

    1997-05-01

    In malt production drying operation plays an important role in the total processing cost, however there are not many studies on malt drying modeling and optimization. In this paper a deep layer malt drying mathematical model in the form of four partial differential equations is presented. To determine drying constants, malt thin layer drying experiments at several air temperatures and relative humidities were made. The model were validated at industrial scale. The greatest energy savings, approximately 5.5% in fuel and 7.5% in electric energy, were obtained by an additional (and increased) air recirculation, which is carried out during the last 6 hours of the drying process and a significant decrease of air flow-rate during the last 6 hours of the drying process.

  18. Dry EEG Electrodes

    PubMed Central

    Lopez-Gordo, M. A.; Sanchez-Morillo, D.; Valle, F. Pelayo

    2014-01-01

    Electroencephalography (EEG) emerged in the second decade of the 20th century as a technique for recording the neurophysiological response. Since then, there has been little variation in the physical principles that sustain the signal acquisition probes, otherwise called electrodes. Currently, new advances in technology have brought new unexpected fields of applications apart from the clinical, for which new aspects such as usability and gel-free operation are first order priorities. Thanks to new advances in materials and integrated electronic systems technologies, a new generation of dry electrodes has been developed to fulfill the need. In this manuscript, we review current approaches to develop dry EEG electrodes for clinical and other applications, including information about measurement methods and evaluation reports. We conclude that, although a broad and non-homogeneous diversity of approaches has been evaluated without a consensus in procedures and methodology, their performances are not far from those obtained with wet electrodes, which are considered the gold standard, thus enabling the former to be a useful tool in a variety of novel applications. PMID:25046013

  19. Theoretical and experimental studies on low-temperature adsorption drying of fresh ginger

    NASA Astrophysics Data System (ADS)

    Yang, Xiaoxi; Xu, Wei; Ding, Jing; Zhao, Yi

    2006-03-01

    The working principle of low-temperature adsorption drying and the advantages of its application for biological materials drying were introduced in this paper. By using fresh ginger as the drying material, the effects of temperature and relative humidity on its drying characteristics were examined. The results show that the drying rate increases with the temperature increasing or the humidity decreasing. The drying time to the equilibrium is almost the same under different humidity conditions, but low equilibrium moisture content can be acquired under low humidity. The shrinkage characteristics of fresh ginger were also studied. The change of its surface appearance during the drying process was characterized by the new Charged Coupled Device (CCD) and the Environmental Scanning Electron Microscopy (ESEM) technique. A mathematical model of drying dynamics was set up according to the experiments.

  20. Biological Filters.

    ERIC Educational Resources Information Center

    Klemetson, S. L.

    1978-01-01

    Presents the 1978 literature review of wastewater treatment. The review is concerned with biological filters, and it covers: (1) trickling filters; (2) rotating biological contractors; and (3) miscellaneous reactors. A list of 14 references is also presented. (HM)

  1. Biological Agents

    MedlinePlus

    ... to Z Index Contact Us FAQs What's New Biological Agents This page requires that javascript be enabled ... and Health Topics A-Z Index What's New Biological agents include bacteria, viruses, fungi, other microorganisms and ...

  2. Steam drying -- Modeling and applications

    SciTech Connect

    Wimmerstedt, R.; Hager, J.

    1996-08-01

    The concept of steam drying originates from the mid of the last century. However, a broad industrial acceptance of the technique has so far not taken place. The paper deals with modelling the steam drying process and applications of steam drying within certain industrial sectors where the technique has been deemed to have special opportunities. In the modelling section the mass and heat transfer processes are described along with equilibrium, capillarity and sorption phenomena occurring in porous materials during the steam drying process. In addition existing models in the literature are presented. The applications discussed involve drying of fuels with high moisture contents, cattle feed exemplified by sugar beet pulp, lumber, paper pulp, paper and sludges. Steam drying is compared to flue gas drying of biofuels prior to combustion in a boiler. With reference to a current installation in Sweden, the exergy losses, as manifested by loss of co-generation capacity, are discussed. The energy saving potential when using steam drying of sugar beet pulp as compared to other possible plant configurations is demonstrated. Mechanical vapor recompression applied to steam drying is analyzed with reference to reported data from industrial plants. Finally, environmental advantages when using steam drying are presented.

  3. Dry aging of beef; Review.

    PubMed

    Dashdorj, Dashmaa; Tripathi, Vinay Kumar; Cho, Soohyun; Kim, Younghoon; Hwang, Inho

    2016-01-01

    The present review has mainly focused on the specific parameters including aging (aging days, temperature, relative humidity, and air flow), eating quality (flavor, tenderness and juiciness), microbiological quality and economic (shrinkage, retail yields and cost) involved beef dry aging process. Dry aging is the process where beef carcasses or primal cuts are hanged and aged for 28 to 55 d under controlling environment conditions in a refrigerated room with 0° to 4 °C and with relative humidity of 75 to 80 %. However there are various opinions on dry aging procedures and purveyors of such products are passionate about their programs. Recently, there has been an increased interest in dry aging process by a wider array of purveyors and retailers in the many countries. Dry aging process is very costly because of high aging shrinkage (6 to15 %), trims loss (3 to 24 %), risk of contamination and the requirement of highest grades meat with. The packaging in highly moisture-permeable bag may positively impact on safety, quality and shelf stability of dry aged beef. The key effect of dry aging is the concentration of the flavor that can only be described as "dry-aged beef". But the contribution of flavor compounds of proteolysis and lipolysis to the cooked dry aged beef flavor is not fully known. Also there are limited scientific studies of aging parameters on the quality and palatability of dry aged beef. PMID:27200180

  4. Characterization of In-Drum Drying Products

    SciTech Connect

    Kroselj, V.; Jankovic, M.; Skanata, D.; Medakovic, S.; Harapin, D.; Hertl, B.

    2006-07-01

    A few years ago Krsko NPP decided to introduce In-Drum Drying technology for treatment and conditioning of evaporator concentrates and spent ion resins. The main reason to employ this technology was the need for waste volume reduction and experience with vermiculite-cement solidification that proved inadequate for Krsko NPP. Use of In-Drum Drying technology was encouraged by good experience in the field at some German and Spanish NPP's. In the paper, solidification techniques in vermiculite-cement matrix and In-Drum Drying System are described briefly. The resulting waste forms (so called solidification and dryer products) and containers that are used for interim storage of these wastes are described as well. A comparison of the drying versus solidification technology is performed and advantages as well as disadvantages are underlined. Experience gained during seven years of system operation has shown that crying technology resulted in volume reduction by factor of 20 for evaporator concentrates, and by factor of 5 for spent ion resin. Special consideration is paid to the characterization of dryer products. For evaporator concentrates the resulting waste form is a solid salt block with up to 5% bound water. It is packaged in stainless steel drums (net volume of 200 l) with bolted lids and lifting rings. The fluidized spent ion resins (primary and blow-down) are sluiced into the spent resin drying tank. The resin is dewatered and dried by electrical jacket heaters. The resulting waste (i.e. fine granulates) is directly discharged into a shielded stainless steel drum with bolted lid and lifting rings. Characterization of both waste forms has been performed in accordance with recommendations given in Characterization of Radioactive Waste Forms and Packages issued by International Atomic Energy Agency, 1997. This means that radiological, chemical, physical, mechanical, biological and thermal properties of the waste form has been taken into consideration. In the paper

  5. Dry ice blasting

    NASA Astrophysics Data System (ADS)

    Lonergan, Jeffrey M.

    1992-04-01

    As legal and societal pressures against the use of hazardous waste generating materials has increased, so has the motivation to find safe, effective, and permanent replacements. Dry ice blasting is a technology which uses CO2 pellets as a blasting medium. The use of CO2 for cleaning and stripping operations offers potential for significant environmental, safety, and productivity improvements over grit blasting, plastic media blasting, and chemical solvent cleaning. Because CO2 pellets break up and sublime upon impact, there is no expended media to dispose of. Unlike grit or plastic media blasting which produce large quantities of expended media, the only waste produced by CO2 blasting is the material removed. The quantity of hazardous waste produced, and thus the cost of hazardous waste disposal is significantly reduced.

  6. Dry Ice Etches Terrain

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Figure 1

    Every year seasonal carbon dioxide ice, known to us as 'dry ice,' covers the poles of Mars. In the south polar region this ice is translucent, allowing sunlight to pass through and warm the surface below. The ice then sublimes (evaporates) from the bottom of the ice layer, and carves channels in the surface.

    The channels take on many forms. In the subimage shown here (figure 1) the gas from the dry ice has etched wide shallow channels. This region is relatively flat, which may be the reason these channels have a different morphology than the 'spiders' seen in more hummocky terrain.

    Observation Geometry Image PSP_003364_0945 was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter spacecraft on 15-Apr-2007. The complete image is centered at -85.4 degrees latitude, 104.0 degrees East longitude. The range to the target site was 251.5 km (157.2 miles). At this distance the image scale is 25.2 cm/pixel (with 1 x 1 binning) so objects 75 cm across are resolved. The image shown here has been map-projected to 25 cm/pixel . The image was taken at a local Mars time of 06:57 PM and the scene is illuminated from the west with a solar incidence angle of 75 degrees, thus the sun was about 15 degrees above the horizon. At a solar longitude of 219.6 degrees, the season on Mars is Northern Autumn.

  7. Dry Arthroscopy of the Elbow

    PubMed Central

    Phadnis, Joideep; Bain, Gregory

    2015-01-01

    Dry arthroscopy is attractive because it affords an unsurpassed clarity of view and minimizes swelling. The elbow is a challenging joint to assess arthroscopically; however, dry arthroscopy has some particular benefits in the elbow. The primary benefit is the quality of the tissue definition, but dry arthroscopy also increases the working time for surgery by reducing swelling and results in less postoperative discomfort for the patient. With dry arthroscopy, all joint surfaces are covered in synovial fluid, which reflects light, to provide a clearer image of the joint surfaces and depth of field. The air-fluid interface provides an uninterrupted appreciation of the synovial recesses and tissue perfusion. This article describes the technique and indications for dry elbow arthroscopy, which will allow other surgeons to reap the benefits of dry arthroscopy without the need for special equipment or changes in their basic technique. PMID:26759772

  8. Dried fruit and dental health.

    PubMed

    Sadler, Michèle Jeanne

    2016-12-01

    A comprehensive review of the literature has found that the common perceptions that dried fruits are "sticky", adhere to teeth, and are detrimental to dental health on account of their sugar content are based on weak evidence. There is a lack of good quality scientific data to support restrictive advice for dried fruit intake on the basis of dental health parameters and further research is required. A number of potentially positive attributes for dental health, such as the need to chew dried fruits which encourages salivary flow, and the presence of anti-microbial compounds and of sorbitol, also require investigation to establish the extent of their effects and whether they balance against any potentially negative attributes of dried fruit. Advice on dried fruit consumption should also take account of the nutritional benefits of dried fruit, being high in fibre, low in fat and containing useful levels of micronutrients.

  9. Fibrillar Amyloid-β Accumulation Triggers an Inflammatory Mechanism Leading to Hyperphosphorylation of the Carboxyl-Terminal End of Tau Polypeptide in the Hippocampal Formation of the 3×Tg-AD Transgenic Mouse.

    PubMed

    Ontiveros-Torres, Miguel Ángel; Labra-Barrios, María Luisa; Díaz-Cintra, Sofía; Aguilar-Vázquez, Azucena Ruth; Moreno-Campuzano, Samadhi; Flores-Rodríguez, Paola; Luna-Herrera, Claudia; Mena, Raúl; Perry, George; Florán-Garduño, Benjamín; Luna-Muñoz, José; Luna-Arias, Juan Pedro

    2016-03-22

    Alzheimer's disease (AD) is a degenerative and irreversible disorder whose progressiveness is dependent on age. It is histopathologically characterized by the massive accumulation of insoluble forms of tau and amyloid-β (Aβ) asneurofibrillary tangles and neuritic plaques, respectively. Many studies have documented that these two polypeptides suffer several posttranslational modifications employing postmortem tissue sections from brains of patients with AD. In order to elucidate the molecular mechanisms underlying the posttranslational modifications of key players in this disease, including Aβ and tau, several transgenic mouse models have been developed. One of these models is the 3×Tg-AD transgenic mouse, carrying three transgenes encoding APPSWE, S1M146V, and TauP301L proteins. To further characterize this transgenicmouse, we determined the accumulation of fibrillar Aβ as a function of age in relation to the hyperphosphorylation patterns of TauP301L at both its N- and C-terminus in the hippocampal formation by immunofluorescence and confocal microscopy. Moreover, we searched for the expression of activated protein kinases and mediators of inflammation by western blot of wholeprotein extracts from hippocampal tissue sections since 3 to 28 months as well. Our results indicate that the presence of fibrillar Aβ deposits correlates with a significant activation of astrocytes and microglia in subiculum and CA1 regions of hippocampus. Accordingly, we also observed a significant increase in the expression of TNF-α associated to neuritic plaques and glial cells. Importantly, there is an overexpression of the stress activated protein kinases SAPK/JNK and Cdk-5 in pyramidal neurons, which might phosphorylate several residues at the C-terminus of TauP301L. Therefore, the accumulation of Aβ oligomers results in an inflammatory environment that upregulates kinases involved in hyperphosphorylation of TauP301L polypeptide.

  10. [Dried fruit as sugar substitute?].

    PubMed

    Strübig, W; Gülzow, H J

    1989-09-01

    Alternative foodstuffs restrict the usage of household sugar and instead recommend sweet honey or dried fruits; in popular informative magazines raisins and dried fruit are even described as "healthy snacks". In this study, with the help of sugar clearance and lactic acid measurements, the cariogenic potential of dried fruits is to be better estimated. The results clearly show that the alternative recommendations do not promote healthy teeth. The cariogenic potential of the named foodstuffs is comparable to sucrose containing products. PMID:2635063

  11. [Biological weapons].

    PubMed

    Kerwat, K; Becker, S; Wulf, H; Densow, D

    2010-08-01

    Biological weapons are weapons of mass destruction that use pathogens (bacteria, viruses) or the toxins produced by them to target living organisms or to contaminate non-living substances. In the past, biological warfare has been repeatedly used. Anthrax, plague and smallpox are regarded as the most dangerous biological weapons by various institutions. Nowadays it seems quite unlikely that biological warfare will be employed in any military campaigns. However, the possibility remains that biological weapons may be used in acts of bioterrorism. In addition all diseases caused by biological weapons may also occur naturally or as a result of a laboratory accident. Risk assessment with regard to biological danger often proves to be difficult. In this context, an early identification of a potentially dangerous situation through experts is essential to limit the degree of damage.

  12. Convective drying of sludge cake

    NASA Astrophysics Data System (ADS)

    Chen, Jianbo; Peng, Xiaofeng; Xue, Yuan; Lee, Duujong; Chu, Chingping

    2002-08-01

    This paper presented an experimental study on convective drying of waste water sludge collected from Beijing GaoBeiDian Sewage Treatment Plant, particularly on the correlation between the observed shrinkage dynamics of sludge cake and the drying curve. During the initial stage of drying the process resembles to that of a particulate bed, in which moisture diffuses and evaporates at the upper surface. Conventional drying theory assuming a diffusion-evaporating front interprets this period of drying. Consequently, owing to the very large shrinkage ratio of the dried cake, cracks emerges and propagates on and within the cake body, whence inducing evaporating channel that facilitates the water removal. This occurrence compensates the reduction of surface area for evaporation, whence extending the constant-rate period during the test. Afterwards, the cracks meet with each other and form isolated cake piles, while the subsequent drying occur mainly within these piles and the conventional theory fails. The transition between the drying on a plain cake layer and that on the isolated piles demonstrates the need to adopt distinct descriptions on these two regimes of drying for the sludge cake.

  13. Space Technology for Crop Drying

    NASA Technical Reports Server (NTRS)

    1980-01-01

    McDonnell Douglas came up with a new method of drying agricultural crops derived from vacuum chamber technology called MIVAC, a compression of microwave vacuum drying system. A distant cousin of the home microwave oven, MIVAC dries by means of electrically- generated microwaves introduced to a crop-containing vacuum chamber. Microwaves remove moisture quickly and the very low pressure atmosphere in the chamber permits effective drying at much lower than customary temperatures. Thus energy demand is doubly reduced by lower heat requirement and by the shorter time electric power is needed.

  14. Molecular programme of senescence in dry and fleshy fruits.

    PubMed

    Gómez, María Dolores; Vera-Sirera, Francisco; Pérez-Amador, Miguel A

    2014-08-01

    Fruits of angiosperms can be divided into dry and fleshy fruits, depending on their dispersal strategies. Despite their apparently different developmental programmes, researchers have attempted to compare dry and fleshy fruits to establish analogies of the distinct biochemical and physiological processes that occur. But what are the common and specific phenomena in both biological strategies? Is valve dehiscence and senescence of dry fruits comparable to final ripening of fleshy fruits, when seeds become mature and fruits are competent for seed dispersal, or to over-ripening when advanced senescence occurs? We briefly review current knowledge on dry and fleshy fruit development, which has been extensively reported recently, and is the topic of this special issue. We compare the processes taking place in Arabidopsis (dry) and tomato (fleshy) fruit during final development steps using transcriptome data to establish possible analogies. Interestingly, the transcriptomic programme of Arabidopsis silique shares little similarity in gene number to tomato fruit ripening or over-ripening. In contrast, the biological processes carried out by these common genes from ripening and over-ripening programmes are similar, as most biological processes are shared during both programmes. On the other hand, several biological terms are specific of Arabidopsis and tomato ripening, including senescence, but little or no specific processes occur during Arabidopsis and tomato over-ripening. These suggest a closer analogy between silique senescence and ripening than over-ripening, but a major common biological programme between Arabidopsis silique senescence and the last steps of tomato development, irrespective of its distinction between ripening and over-ripening.

  15. Optical anisotropy of fibrous biological tissues: analysis of the influence of structural properties

    SciTech Connect

    Zimnyakov, D A; Sinichkin, Yu P; Ushakova, O V

    2007-08-31

    The results of theoretical analysis of the optical anisotropy of multiply scattering fibrillar biological tissues based on the model of an effective anisotropic medium are compared with the experimental in vivo birefringence data for the rat derma obtained earlier in spectral polarisation measurements of rat skin samples in the visible region. The disordered system of parallel dielectric cylinders embedded into an isotropic dielectric medium was considered as a model medium. Simulations were performed taking into account the influence of a partial mutual disordering of the bundles of collagen and elastin fibres in derma on birefringence in samples. The theoretical optical anisotropy averaged over the spectral interval 550-650 nm for the model medium with parameters corresponding to the structural parameters of derma is in good agreement with the results of spectral polarisation measurements of skin samples in the corresponding wavelength range. (laser methods in biology)

  16. Molecular and Biological Compatibility with Host Alpha-Synuclein Influences Fibril Pathogenicity.

    PubMed

    Luk, Kelvin C; Covell, Dustin J; Kehm, Victoria M; Zhang, Bin; Song, Insung Y; Byrne, Matthew D; Pitkin, Rose M; Decker, Samantha C; Trojanowski, John Q; Lee, Virginia M-Y

    2016-09-20

    The accumulation and propagation of misfolded α-synuclein (α-Syn) is a central feature of Parkinson's disease and other synucleinopathies. Molecular compatibility between a fibrillar seed and its native protein state is a major determinant of amyloid self-replication. We show that cross-seeded aggregation of human (Hu) and mouse (Ms) α-Syn is bidirectionally restricted. Although fibrils formed by Hu-Ms-α-Syn chimeric mutants can overcome this inhibition in cell-free systems, sequence homology poorly predicts their efficiency in inducing α-Syn pathology in primary neurons or after intracerebral injection into wild-type mice. Chimeric α-Syn fibrils demonstrate enhanced or reduced pathogenicities compared with wild-type Hu- or Ms-α-Syn fibrils. Furthermore, α-Syn mutants induced to polymerize by fibrillar seeds inherit the functional properties of their template, suggesting that transferable pathogenic and non-pathogenic states likely influence the initial engagement between exogenous α-Syn seeds and endogenous neuronal α-Syn. Thus, transmission of synucleinopathies is regulated by biological processes in addition to molecular compatibility. PMID:27653697

  17. Dry sump crankcase

    SciTech Connect

    Berger, A.H.; Dichi, R.E.

    1987-06-23

    A dry sump type crankcase is described for an automotive type internal combustion engine having an intake manifold and a positive crankcase ventilation (PCV) system for automatically and continuously ventilating the crankcase. The system includes an essentially atmospheric pressure fresh air inlet to the engine passing air through to the crankcase and a connection from the oil pan to the vacuum in the intake manifold establishing a constant flow of crankcase vapors. The oil pan has a baffle partitioning it into an inner oil collecting funnel-like crankcase cavity and an outer oil reservoir. The inner cavity has an opening at its lower-most point for communication of oil with the reservoir. The opening is of a controlled vertical height for creating a pressure differential across the baffle during operation of the engine. Means connects the inner cavity to the air inlet pressure side of the PCV System while connecting the reservoir to the vacuum side of the PCV system for establishing a constant pressure differential across the baffle sufficient to displace the oil against gravity and maintain the oil level in the crankcase during operation of the engine at the height of the opening in the baffle. Gravity causes the oil to seek a level higher than the opening upon shutdown of the engine and the consequential decay of vacuum in the intake manifold.

  18. Wet Mars, Dry Mars

    NASA Astrophysics Data System (ADS)

    Fillingim, M. O.; Brain, D. A.; Peticolas, L. M.; Yan, D.; Fricke, K. W.; Thrall, L.

    2012-12-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our lessons learned from evaluations, and show (pictures of) our hands-on activities and 3D models.

  19. Wet Mars, Dry Mars

    NASA Astrophysics Data System (ADS)

    Fillingim, Matthew; Brain, D.; Peticolas, L.; Yan, D.; Fricke, K.; Thrall, L.

    2012-10-01

    The magnetic fields of the large terrestrial planets, Venus, Earth, and Mars, are all vastly different from each other. These differences can tell us a lot about the interior structure, interior history, and even give us clues to the atmospheric history of these planets. This poster highlights the third in a series of presentations that target school-age audiences with the overall goal of helping the audience visualize planetary magnetic field and understand how they can impact the climatic evolution of a planet. Our first presentation, "Goldilocks and the Three Planets," targeted to elementary school age audiences, focuses on the differences in the atmospheres of Venus, Earth, and Mars and the causes of the differences. The second presentation, "Lost on Mars (and Venus)," geared toward a middle school age audience, highlights the differences in the magnetic fields of these planets and what we can learn from these differences. Finally, in the third presentation, "Wet Mars, Dry Mars," targeted to high school age audiences and the focus of this poster, the emphasis is on the long term climatic affects of the presence or absence of a magnetic field using the contrasts between Earth and Mars. These presentations are given using visually engaging spherical displays in conjunction with hands-on activities and scientifically accurate 3D models of planetary magnetic fields. We will summarize the content of our presentations, discuss our "lessons learned" from formative evaluation, and show (pictures of) our hands-on activities and 3D models.

  20. Staying dry under water

    NASA Astrophysics Data System (ADS)

    Jones, Paul; Cruz-Chu, Eduardo; Megaridis, Constantine; Walther, Jens; Koumoutsakos, Petros; Patankar, Neelesh

    2012-11-01

    Lotus leaves are known for their non-wetting properties due to the presence of surface texture. The superhydrophobic behavior arises because of the prevention of liquid water from entering the pores of the roughness. Present superhydrophobic materials rely on air trapped within the surface pores to avoid liquid permeation. This is typically unsustainable for immersed bodies due to dissolution of the air, especially under elevated pressures. Here, molecular dynamics simulations are used to demonstrate the non-wetting behavior of an immersed ten-nanometer pore. This is accomplished by establishing thermodynamically sustained vapor pockets of the surrounding liquid medium. Over 300,000 atoms were used to construct the nanopore geometry and simulate SPC/E water molecules. Ambient pressure was varied along two isotherms (300 K, and 500 K). This approach for vapor-stabilization could offer valuable guidance for maintaining surfaces dry even in a submerged state without relying on trapped air. The approach may be extended to control general phase behavior of water adjacent to textured surfaces. ISEN support is gratefully acknowledged.

  1. Forward Osmosis Brine Drying

    NASA Technical Reports Server (NTRS)

    Flynn, Michael; Shaw, Hali; Hyde, Deirdre; Beeler, David; Parodi, Jurek

    2015-01-01

    The Forward Osmosis Brine Drying (FOBD) system is based on a technique called forward osmosis (FO). FO is a membrane-based process where the osmotic potential between brine and a salt solution is equalized by the movement of water from the brine to the salt solution. The FOBD system is composed of two main elements, the FO bag and the salt regeneration system. This paper discusses the results of testing of the FO bag to determine the maximum water recovery ratio that can be attained using this technology. Testing demonstrated that the FO bag is capable of achieving a maximum brine water recovery ratio of the brine of 95%. The equivalent system mass was calculated to be 95 kg for a feed similar to the concentrated brine generated on the International Space Station and 86 kg for an Exploration brine. The results have indicated that the FOBD can process all the brine for a one year mission for between 11% to 10% mass required to bring the water needed to make up for water lost in the brine if not recycled. The FOBD saves 685 kg and when treating the International Space Station brine and it saves 829 kg when treating the Exploration brine. It was also demonstrated that saturated salt solutions achieve a higher water recovery ratios than solids salts do and that lithium chloride achieved a higher water recovery ratio than sodium chloride.

  2. Dry wind tunnel system

    NASA Technical Reports Server (NTRS)

    Chen, Ping-Chih (Inventor)

    2013-01-01

    This invention is a ground flutter testing system without a wind tunnel, called Dry Wind Tunnel (DWT) System. The DWT system consists of a Ground Vibration Test (GVT) hardware system, a multiple input multiple output (MIMO) force controller software, and a real-time unsteady aerodynamic force generation software, that is developed from an aerodynamic reduced order model (ROM). The ground flutter test using the DWT System operates on a real structural model, therefore no scaled-down structural model, which is required by the conventional wind tunnel flutter test, is involved. Furthermore, the impact of the structural nonlinearities on the aeroelastic stability can be included automatically. Moreover, the aeroservoelastic characteristics of the aircraft can be easily measured by simply including the flight control system in-the-loop. In addition, the unsteady aerodynamics generated computationally is interference-free from the wind tunnel walls. Finally, the DWT System can be conveniently and inexpensively carried out as a post GVT test with the same hardware, only with some possible rearrangement of the shakers and the inclusion of additional sensors.

  3. Sessile nanofluid droplet drying.

    PubMed

    Zhong, Xin; Crivoi, Alexandru; Duan, Fei

    2015-03-01

    Nanofluid droplet evaporation has gained much audience nowadays due to its wide applications in painting, coating, surface patterning, particle deposition, etc. This paper reviews the drying progress and deposition formation from the evaporative sessile droplets with the suspended insoluble solutes, especially nanoparticles. The main content covers the evaporation fundamental, the particle self-assembly, and deposition patterns in sessile nanofluid droplet. Both experimental and theoretical studies are presented. The effects of the type, concentration and size of nanoparticles on the spreading and evaporative dynamics are elucidated at first, serving the basis for the understanding of particle motion and deposition process which are introduced afterward. Stressing on particle assembly and production of desirable residue patterns, we express abundant experimental interventions, various types of deposits, and the effects on nanoparticle deposition. The review ends with the introduction of theoretical investigations, including the Navier-Stokes equations in terms of solutions, the Diffusion Limited Aggregation approach, the Kinetic Monte Carlo method, and the Dynamical Density Functional Theory. Nanoparticles have shown great influences in spreading, evaporation rate, evaporation regime, fluid flow and pattern formation of sessile droplets. Under different experimental conditions, various deposition patterns can be formed. The existing theoretical approaches are able to predict fluid dynamics, particle motion and deposition patterns in the particular cases. On the basis of further understanding of the effects of fluid dynamics and particle motion, the desirable patterns can be obtained with appropriate experimental regulations. PMID:25578408

  4. Whey drying on porous carriers

    SciTech Connect

    Mitura, E.; Kaminski, W.

    1996-05-01

    Whey is treated very often as a waste which pollutes the natural environment. Whey which is a valuable source of protein, lacrose, vitamins and mineral salts should be utilized completely. The present paper is a proposal of whey drying on porous carriers. It is proved experimentally that the proposed drying method guarantees good product quality.

  5. Biohazards in pharmaceutical freeze drying.

    PubMed

    Hermanský, M; Graichman, T

    1990-01-01

    Among freeze-dried drugs there are many which may imperil manufacturing personnel, e.g. cytostatic drugs possessing carcinogenic effects. Production zones must be specially adapted for handling such drugs. There are many risks endangering a freeze-drying operation--power or water supply failure, but also improperly established freeze-drying cycle. A production batch of a rare, expensive and sensitive product represents a big value; modern equipment therefore features sophisticated automation, overriding possible human error. Problem of particulate contamination is less severe with vials stoppered inside the vacuum chamber, but rubber closures still may become a source of haze. Back-migration of oil from vacuum pumps may be another source. Economy of industrial freeze-drying may be much improved if freezing sequence, drying rate, adjustment of vacuum by "bleeding" nitrogen are tailored specially for each particular product.

  6. Systems Biology

    SciTech Connect

    Wiley, H S.

    2006-06-01

    The biology revolution over the last 50 years has been driven by the ascendancy of molecular biology. This was enthusiastically embraced by most biologists because it took us into increasingly familiar territory. It took mysterious processes, such as the replication of genetic material and assigned them parts that could be readily understood by the human mind. When we think of ''molecular machines'' as being the underlying basis of life, we are using a paradigm derived from everyday experience. However, the price that we paid was a relentless drive towards reductionism and the attendant balkanization of biology. Now along comes ''systems biology'' that promises us a solution to the problem of ''knowing more and more about less and less''. Unlike molecular biology, systems biology appears to be taking us into unfamiliar intellectual territory, such as statistics, mathematics and computer modeling. Not surprisingly, systems biology has met with widespread skepticism and resistance. Why do we need systems biology anyway and how does this new area of research promise to change the face of biology in the next couple of decades?

  7. Space and Industrial Brine Drying Technologies

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.; Wisniewski, Richard S.; Flynn, Michael; Shaw, Hali

    2014-01-01

    This survey describes brine drying technologies that have been developed for use in space and industry. NASA has long considered developing a brine drying system for the International Space Station (ISS). Possible processes include conduction drying in many forms, spray drying, distillation, freezing and freeze drying, membrane filtration, and electrical processes. Commercial processes use similar technologies. Some proposed space systems combine several approaches. The current most promising candidates for use on the ISS use either conduction drying with membrane filtration or spray drying.

  8. Hot, Dry and Cloudy

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of Hot, Dry and Cloudy

    This artist's concept shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA's Spitzer Space Telescope was recently used to capture spectra, or molecular fingerprints, of two 'hot Jupiter' worlds like the one depicted here. This is the first time a spectrum has ever been obtained for an exoplanet, or a planet beyond our solar system.

    The ground-breaking observations were made with Spitzer's spectrograph, which pries apart infrared light into its basic wavelengths, revealing the 'fingerprints' of molecules imprinted inside. Spitzer studied two planets, HD 209458b and HD 189733b, both of which were found, surprisingly, to have no water in the tops of their atmospheres. The results suggest that the hot planets are socked in with dry, high clouds, which are obscuring water that lies underneath. In addition, HD209458b showed hints of silicates, suggesting that the high clouds on that planet contain very fine sand-like particles.

    Capturing the spectra from the two hot-Jupiter planets was no easy feat. The planets cannot be distinguished from their stars and instead appear to telescopes as single blurs of light. One way to get around this is through what is known as the secondary eclipse technique. In this method, changes in the total light from a so-called transiting planet system are measured as a planet is eclipsed by its star, vanishing from our Earthly point of view. The dip in observed light can then be attributed to the planet alone.

    This technique, first used by Spitzer in 2005 to directly detect the light from an exoplanet, currently only works at infrared wavelengths, where the differences in brightness between the planet and star are less, and the planet's light is easier to pick out. For example, if the experiment had been done in visible light, the total light from the system would appear to be unchanged

  9. Is synthetic biology mechanical biology?

    PubMed

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  10. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including use of dwarf cichlids (fishes) in secondary school biology, teaching edge effects on stomatal diffusion, computer program on effects of selection on gene frequencies, biological oxidation/reduction reactions, short cuts with Drosophila, computer program…

  11. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1978

    1978-01-01

    Presents experiments, demonstrations, activities and ideas relating to various fields of biology to be used in biology courses in secondary schools. Among those experiments presented are demonstrating the early stages of ferns and mosses and simple culture methods for fern prothalli. (HM)

  12. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1982

    1982-01-01

    Presents procedures, exercises, demonstrations, and information on a variety of biology topics including labeling systems, biological indicators of stream pollution, growth of lichens, reproductive capacity of bulbous buttercups, a straw balance to measure transpiration, interaction of fungi, osmosis, and nitrogen fixation and crop production. (DC)

  13. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including chi-square tests on a microcomputer, an integrated biology game, microscope slides of leaf stomata, culturing soil nematodes, technique for watering locust egg-laying tubes, hazards of biological chemicals (such as benzene, benzidene, calchicine,…

  14. High-intensity drying processes: Impulse drying. Annual report

    SciTech Connect

    Orloff, D.I.; Phelan, P.M.

    1993-12-01

    Experiments were conducted on a sheet-fed pilot-scale shoe press to compare impulse drying and double-felted pressing. Both an IPST (Institute of Paper Science and Technology) ceramic coated and Beloit Type A press roll were evaluated for lienrboard sheet structures having a wide range of z-direction permeability. Purpose was to find ways of correcting sheet sticking problems observed in previous pilot-scale shoe press experiments. Results showed that impulse drying was superior to double felted pressing in both press dryness and in important paper physical properties. Impulse drying critical temperature was found to depend on specific surface of the heated layer of the sheet, thermal properties of the press roll surface, and choice of felt. Impulse drying of recycled and two-ply liner was demonstrated for both Southern Pile and Douglas fir-containing furnishes.

  15. 7 CFR 58.239 - Drying.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Drying. 58.239 Section 58.239 Agriculture Regulations... Drying. Each dryer should be operated to produce the highest quality dry product consistent with the most efficient operation. The dry products shall be removed from the drying chamber continuously during...

  16. 7 CFR 58.239 - Drying.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Drying. 58.239 Section 58.239 Agriculture Regulations... Drying. Each dryer should be operated to produce the highest quality dry product consistent with the most efficient operation. The dry products shall be removed from the drying chamber continuously during...

  17. 7 CFR 58.239 - Drying.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Drying. 58.239 Section 58.239 Agriculture Regulations... Drying. Each dryer should be operated to produce the highest quality dry product consistent with the most efficient operation. The dry products shall be removed from the drying chamber continuously during...

  18. 7 CFR 58.239 - Drying.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Drying. 58.239 Section 58.239 Agriculture Regulations... Drying. Each dryer should be operated to produce the highest quality dry product consistent with the most efficient operation. The dry products shall be removed from the drying chamber continuously during...

  19. 7 CFR 58.239 - Drying.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Drying. 58.239 Section 58.239 Agriculture Regulations... Drying. Each dryer should be operated to produce the highest quality dry product consistent with the most efficient operation. The dry products shall be removed from the drying chamber continuously during...

  20. [Conservative treatment of dry eye].

    PubMed

    Hefner, J; Reinshagen, H

    2014-11-01

    The use of topic anti-inflammatory drugs has become very important in the treatment of dry eye disease. Besides the basic therapy including tear replacement, use of serum eye drops and mucolytic eye drops, the topical application of corticosteroids and cyclosporin A is more commonly used in moderate to severe forms of dry eye disease. The consistent treatment of Meibomian gland dysfunction as a frequent reason for evaporative dry eye is also of particular importance. Understanding the chronicity of the disease and long-term compliance are the essential for successful therapy of this widespread disease.

  1. Aging and dry eye disease.

    PubMed

    Ding, Juan; Sullivan, David A

    2012-07-01

    Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD.

  2. Aging and dry eye disease

    PubMed Central

    Ding, Juan; Sullivan, David A.

    2012-01-01

    Dry eye disease is a prevalent eye disorder that in particular affects the elderly population. One of the major causes of dry eye, meibomian gland dysfunction (MGD), shows increased prevalence with aging. MGD is caused by hyperkeratinization of the ductal epithelium of meibomian gland and reduced quantity and/or quality of meibum, the holocrine product that stabilizes and prevents the evaporation of the tear film. Of note, retinoids which are used in current anti-aging cosmetics may promote the development of MGD and dry eye disease. In this review, we will discuss the possible mechanisms of age-related MGD. PMID:22569356

  3. [Conservative treatment of dry eye].

    PubMed

    Hefner, J; Reinshagen, H

    2014-11-01

    The use of topic anti-inflammatory drugs has become very important in the treatment of dry eye disease. Besides the basic therapy including tear replacement, use of serum eye drops and mucolytic eye drops, the topical application of corticosteroids and cyclosporin A is more commonly used in moderate to severe forms of dry eye disease. The consistent treatment of Meibomian gland dysfunction as a frequent reason for evaporative dry eye is also of particular importance. Understanding the chronicity of the disease and long-term compliance are the essential for successful therapy of this widespread disease. PMID:25275793

  4. Drying of poloxamer hydrogel films.

    PubMed

    Gu, Zhiyong; Alexandridis, Paschalis

    2004-06-01

    The drying of hydrogel films formed by Poloxamer 407 poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) amphiphilic block copolymer was investigated at various air relative humidity (RH) conditions ranging from 11 to 97%. Initially, the amount of water lost increased linearly with the drying time. After this linear region (stage I), a nonlinear behavior was observed (stage II). The drying rate increased with decreasing RH, thus greatly shortening the drying time. A decrease of the film thickness also shortened the drying time; however, the drying mechanism did not change. Three models for one-dimensional water diffusion were used to fit the experimental results at different RH conditions and film thicknesses. Model 1 assumes semi-infinite medium and constant diffusion coefficient, and fits very well the data in stage I of the drying process. The fitted water diffusion coefficient (D) is 5 x 10(-10) m(2)/s, whereas the effects of the RH are captured by a proportionality constant (alpha) that appears in the boundary condition. Model 2 considers a finite (constant) film thickness and captures the experimental observations over the whole drying period for the same D and alpha as in Model 1. The analytical solutions available for Models 1 and 2, used together with the experimentally derived model parameters D and alpha, allow for easy estimation of drying time and water loss from Poloxamer hydrogel films of various compositions and thicknesses and at different relative humidities. Numerical solutions for water diffusion under conditions of decreasing film thickness and diffusion coefficient being a function of concentration are also presented (Model 3). It becomes apparent from the fit of the data to the different models that the drying rate is more sensitive to the boundary condition at the film-air interface (represented by alpha) than to the diffusion in the film. It is notable that the alpha values obtained from the fits of the Poloxamer hydrogel drying

  5. Spent fuel drying system test results (second dry-run)

    SciTech Connect

    Klinger, G.S.; Oliver, B.M.; Abrefah, J.; Marschman, S.C.; MacFarlan, P.J.; Ritter, G.A.

    1998-07-01

    The water-filled K-Basins in the Hanford 100 Area have been used to store N-Reactor spent nuclear fuel (SNF) since the 1970s. Because some leaks have been detected in the basins and some of the fuel is breached due to handling damage and corrosion, efforts are underway to remove the fuel elements from wet storage. An Integrated Process Strategy (IPS) has been developed to package, dry, transport, and store these metallic uranium fuel elements in an interim storage facility on the Hanford Site (WHC 1995). Information required to support the development of the drying processes, and the required safety analyses, is being obtained from characterization tests conducted on fuel elements removed from the K-Basins. A series of whole element drying tests (reported in separate documents, see Section 7.0) have been conducted by Pacific Northwest National Laboratory (PNNL) on several intact and damaged fuel elements recovered from both the K-East and K-West Basins. This report documents the results of the second dry-run test, which was conducted without a fuel element. With the concurrence of project management, the test protocol for this run, and subsequent drying test runs, was modified. These modifications were made to allow for improved data correlation with drying procedures proposed under the IPS. Details of these modifications are discussed in Section 3.0.

  6. Biological Oceanography

    NASA Astrophysics Data System (ADS)

    Dyhrman, Sonya

    2004-10-01

    The ocean is arguably the largest habitat on the planet, and it houses an astounding array of life, from microbes to whales. As a testament to this diversity and its importance, the discipline of biological oceanography spans studies of all levels of biological organization, from that of single genes, to organisms, to their population dynamics. Biological oceanography also includes studies on how organisms interact with, and contribute to, essential global processes. Students of biological oceanography are often as comfortable looking at satellite images as they are electron micrographs. This diversity of perspective begins the textbook Biological Oceanography, with cover graphics including a Coastal Zone Color Scanner image representing chlorophyll concentration, an electron micrograph of a dinoflagellate, and a photograph of a copepod. These images instantly capture the reader's attention and illustrate some of the different scales on which budding oceanographers are required to think. Having taught a core graduate course in biological oceanography for many years, Charlie Miller has used his lecture notes as the genesis for this book. The text covers the subject of biological oceanography in a manner that is targeted to introductory graduate students, but it would also be appropriate for advanced undergraduates.

  7. Sustaining dry surfaces under water

    PubMed Central

    Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.; Rykaczewski, Konrad; Nandy, Krishanu; Schutzius, Thomas M.; Varanasi, Kripa K.; Megaridis, Constantine M.; Walther, Jens H.; Koumoutsakos, Petros; Espinosa, Horacio D.; Patankar, Neelesh A.

    2015-01-01

    Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have not been investigated, and are critically important to maintain surfaces dry under water. In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical predictions are consistent with molecular dynamics simulations and experiments. PMID:26282732

  8. Physiologic effects of dry needling.

    PubMed

    Cagnie, Barbara; Dewitte, Vincent; Barbe, Tom; Timmermans, Frank; Delrue, Nicolas; Meeus, Mira

    2013-08-01

    During the past decades, worldwide clinical and scientific interest in dry needling (DN) therapy has grown exponentially. Various clinical effects have been credited to dry needling, but rigorous evidence about its potential physiological mechanisms of actions and effects is still lacking. Research identifying these exact mechanisms of dry needling action is sparse and studies performed in an acupuncture setting do not necessarily apply to DN. The studies of potential effects of DN are reviewed in reference to the different aspects involved in the pathophysiology of myofascial triggerpoints: the taut band, local ischemia and hypoxia, peripheral and central sensitization. This article aims to provide the physiotherapist with a greater understanding of the contemporary data available: what effects could be attributed to dry needling and what are their potential underlying mechanisms of action, and also indicate some directions at which future research could be aimed to fill current voids.

  9. BIOLOGICAL WARFARE

    PubMed Central

    Beeston, John

    1953-01-01

    The use of biological agents as controlled weapons of war is practical although uncertain. Three types of agents are feasible, including pathogenic organisms and biological pests, toxins, and synthetic hormones regulating plant growth. These agents may be chosen for selective effects varying from prolonged incipient illness to death of plants, man and domestic animals. For specific preventive and control measures required to combat these situations, there must be careful and detailed planning. The nucleus of such a program is available within the existing framework of public health activities. Additional research and expansion of established activities in time of attack are necessary parts of biological warfare defense. PMID:13059641

  10. Biological post

    PubMed Central

    Kumar, B. Suresh; Kumar, Senthil; Mohan Kumar, N. S.; Karunakaran, J. V.

    2015-01-01

    Anterior tooth fracture as a result of traumatic injuries, is frequently encountered in endodontic practice. Proper reconstruction of extensively damaged teeth can be achieved through the fragment reattachment procedure known as “biological restoration.” This case report refers to the esthetics and functional recovery of extensively damaged maxillary central incisor through the preparation and adhesive cementation of “biological post” in a young patient. Biological post obtained through extracted teeth from another individual–represent a low-cost option and alternative technique for the morphofunctional recovery of extensively damaged anterior teeth. PMID:26538952

  11. Drying in cyclones -- A review

    SciTech Connect

    Nebra, S.A.; Silva, M.A.; Mujumdar, A.S.

    2000-03-01

    This paper presents an overview of the flow, heat and mass transfer characteristics of vortex (or cyclone) dryers. The focus is on the potential of the cyclone configuration for drying of particulates. A selective review is made of the literature pertains to single phase and gas-particle flow in cyclone geometries. Recent data on drying of particulates in cyclone dryers are summarized. 56 refs.

  12. Dry PMR-15 Resin Powders

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D.; Roberts, Gary D.

    1988-01-01

    Shelf lives of PMR-15 polymides lengthened. Procedure involves quenching of monomer reactions by vacuum drying of PRM-15 resin solutions at 70 to 90 degree F immediately after preparation of solutions. Absence of solvent eliminates formation of higher esters and reduces formation of imides to negligible level. Provides fully-formulated dry PMR-15 resin powder readily dissolvable in solvent at room temperature immediately before use. Resins used in variety of aerospace, aeronautical, and commercial applications.

  13. Isolation, Characterization and Biological Evaluation of Jellyfish Collagen for Use in Biomedical Applications

    PubMed Central

    Addad, Sourour; Exposito, Jean-Yves; Faye, Clément; Ricard-Blum, Sylvie; Lethias, Claire

    2011-01-01

    Fibrillar collagens are the more abundant extracellular proteins. They form a metazoan-specific family, and are highly conserved from sponge to human. Their structural and physiological properties have been successfully used in the food, cosmetic, and pharmaceutical industries. On the other hand, the increase of jellyfish has led us to consider this marine animal as a natural product for food and medicine. Here, we have tested different Mediterranean jellyfish species in order to investigate the economic potential of their collagens. We have studied different methods of collagen purification (tissues and experimental procedures). The best collagen yield was obtained using Rhizostoma pulmo oral arms and the pepsin extraction method (2–10 mg collagen/g of wet tissue). Although a significant yield was obtained with Cotylorhiza tuberculata (0.45 mg/g), R. pulmo was used for further experiments, this jellyfish being considered as harmless to humans and being an abundant source of material. Then, we compared the biological properties of R. pulmo collagen with mammalian fibrillar collagens in cell cytotoxicity assays and cell adhesion. There was no statistical difference in cytotoxicity (p > 0.05) between R. pulmo collagen and rat type I collagen. However, since heparin inhibits cell adhesion to jellyfish-native collagen by 55%, the main difference is that heparan sulfate proteoglycans could be preferentially involved in fibroblast and osteoblast adhesion to jellyfish collagens. Our data confirm the broad harmlessness of jellyfish collagens, and their biological effect on human cells that are similar to that of mammalian type I collagen. Given the bioavailability of jellyfish collagen and its biological properties, this marine material is thus a good candidate for replacing bovine or human collagens in selected biomedical applications. PMID:21747742

  14. The Kiln Drying of Wood for Airplanes

    NASA Technical Reports Server (NTRS)

    Tiemann, Harry D

    1919-01-01

    This report is descriptive of various methods used in the kiln drying of woods for airplanes and gives the results of physical tests on different types of woods after being dried by the various kiln-drying methods.

  15. Dry adhesives with sensing features

    NASA Astrophysics Data System (ADS)

    Krahn, J.; Menon, C.

    2013-08-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm2.

  16. Dry mouth and older people.

    PubMed

    Thomson, W M

    2015-03-01

    Dry mouth is more common among older people than in any other age group. Appropriate definition and accurate measurement of dry mouth is critical for better understanding, monitoring and treatment of the condition. Xerostomia is the symptom(s) of dry mouth; it can be measured using methods ranging from single questions to multi-item summated rating scales. Low salivary flow (known as salivary gland hypofunction, or SGH) must be determined by measuring that flow. The relationship between SGH and xerostomia is not straightforward, but both conditions are common among older people, and they affect sufferers' day-to-day lives in important ways. The major risk factor for dry mouth is the taking of particular medications, and older people take more of those than any other age group, not only for symptomatic relief of various age-associated chronic diseases, but also in order to reduce the likelihood of complications which may arise from those conditions. The greater the number taken, the greater the associated anticholinergic burden, and the more likely it is that the individual will suffer from dry mouth. Since treating dry mouth is such a challenge for clinicians, there is a need for dentists, doctors and pharmacists to work together to prevent it occurring.

  17. Drying temperature effects on fish dry mass measurements

    USGS Publications Warehouse

    Lantry, B.F.; O'Gorman, R.

    2007-01-01

    Analysis of tissue composition in fish often requires dry samples. Time needed to dry fish decreases as temperature is increased, but additional volatile material may be lost. Effects of 10??C temperature increases on percentage dry mass (%DM) were tested against 60??C controls for groups of lake trout Salvelinus namaycush, rainbow smelt Osmerus mordax, slimy sculpin Cottus cognatus, and alewife Alosa pseudoharengus. Lake trout %DMs were lower at greater temperatures, but not significantly different from 60??C controls. Rainbow smelt and slimy sculpin %DMs were lower at greater temperatures and differences were significant when test temperatures reached 90??C. Significant differences were not found in tests using alewives because variability in %DM was high between fish. To avoid inter-fish variability, 30 alewives were each dried successively at 60, 70, 80, and then 90??C and for all fish %DM declined at each higher temperature. In general, %DMs were lower at greater temperatures and after reaching a stable dry weight, fish did not lose additional mass if temperature remained constant. Results indicate that caution should be used when comparing dry mass related indices from fish dried at different temperatures because %DM was negatively related to temperature. The differences in %DM observed with rising temperature could account for substantial portions of the variability in reported energy values for the species tested. Differences in %DM means for the 60 vs. 80??C and 60 vs. 90??C tests for rainbow smelt and alewife could represent of from 8 to 38% of observed annual energy cycles for Lakes Ontario and Michigan.

  18. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Twelve new experiments in biology are described by teachers for use in classrooms. Broad areas covered include enzyme action, growth regulation, microscopy, respiration, germination, plant succession, leaf structure and blood structure. Explanations are detailed. (PS)

  19. Bottle Biology.

    ERIC Educational Resources Information Center

    CSTA Journal, 1995

    1995-01-01

    Provides hands-on biology activities using plastic bottles that allow students to become engaged in asking questions, creating experiments, testing hypotheses, and generating answers. Activities explore terrestrial and aquatic systems. (MKR)

  20. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1973

    1973-01-01

    Some helpful ideas are proposed for use by biology teachers. Topics included are Food Webs,'' Key to Identification of Families,'' Viruses,'' Sieve Tube,'' Woodlice,'' Ecology of Oak Leaf Roller Moth,'' and Model Making.'' (PS)

  1. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1972

    1972-01-01

    Ten ideas that have been tried out by the authors in schools are presented for biology teachers. The areas covered include genetics, dispersal of seeds, habituation in earthworms, respiration, sensory neurons, fats and oils. A reading list is provided. (PS)

  2. Fundamentals of freeze-drying.

    PubMed

    Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

    2002-01-01

    Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction

  3. A wetting and drying scheme for ROMS

    USGS Publications Warehouse

    Warner, John C.; Defne, Zafer; Haas, Kevin; Arango, Hernan G.

    2013-01-01

    The processes of wetting and drying have many important physical and biological impacts on shallow water systems. Inundation and dewatering effects on coastal mud flats and beaches occur on various time scales ranging from storm surge, periodic rise and fall of the tide, to infragravity wave motions. To correctly simulate these physical processes with a numerical model requires the capability of the computational cells to become inundated and dewatered. In this paper, we describe a method for wetting and drying based on an approach consistent with a cell-face blocking algorithm. The method allows water to always flow into any cell, but prevents outflow from a cell when the total depth in that cell is less than a user defined critical value. We describe the method, the implementation into the three-dimensional Regional Oceanographic Modeling System (ROMS), and exhibit the new capability under three scenarios: an analytical expression for shallow water flows, a dam break test case, and a realistic application to part of a wetland area along the Georgia Coast, USA.

  4. High-intensity drying processes-impulse drying. Yearly report

    SciTech Connect

    Orloff, D.I.

    1991-06-01

    Impulse drying is an innovative process for drying paper that holds great promise for reducing the energy consumed during the manufacture of paper and similar web products. impulse drying occurs when a wet paper web passes through a press nip in which one of the rolls is heated to a high temperature. A steam layer adjacent to the heated surface grows and displaces water from the sheet in a very efficient manner. The energy required for water removal is very much less than that required for conventional evaporative drying. To eliminate sheet delamination, low thermal mass ceramic press roll coatings were developed to reduce heat transfer to the sheet, while maintaining high heat flux during early stages of the process. In so doing, most of the transferred energy is used to form steam that displaces liquid water, rather than in excessively heating the sheet. During this period, a prototype ceramic coating was developed and its impulse drying performance was compared to that of steel surfaces. It was observed that ceramic platens can be operated at higher temperatures and pressures resulting in improved water removal and physical properties without inducing sheet delamination. Heat flux measurement techniques were developed to provide a mechanistic explanation for the superior performance of the prototype. The work confirmed that the prototype ceramic coating is more energy efficient than the steel surface.

  5. Gas storage in "dry water" and "dry gel" clathrates.

    PubMed

    Carter, Benjamin O; Wang, Weixing; Adams, Dave J; Cooper, Andrew I

    2010-03-01

    "Dry water" (DW) is a free-flowing powder prepared by mixing water, hydrophobic silica particles, and air at high speeds. We demonstrated recently that DW can be used to dramatically enhance methane uptake rates in methane gas hydrate (MGH). Here, we expand on our initial work, demonstrating that DW can be used to increase the kinetics of formation of gas clathrates for gases other than methane, such as CO(2) and Kr. We also show that the stability of the system toward coalescence can be increased via the inclusion of a gelling agent to form a "dry gel", thus dramatically improving the recyclability of the material. For example, the addition of gellan gum allows effective reuse over at least eight clathration cycles without the need for reblending. DW and its "dry gel" modification may represent a potential platform for recyclable gas storage or gas separation on a practicable time scale in a static, unmixed system.

  6. Combination of electron microscopic in situ hybridization and anti-DNA antibody labelling reveals a peculiar arrangement of ribosomal DNA in the fibrillar centres of the plant cell nucleolus.

    PubMed

    Yano, Hiroyuki; Sato, Seiichi

    2002-01-01

    The fibrillar centres (FCs) in the nucleoli of Allium cepa usually contained compact dense chromatin, which was always surrounded with light fibrous material (LFM). Distribution of 18S ribosomal DNA (rDNA) in the FCs was examined by in situ hybridization at the light and electron microscopic levels and the results were compared with those obtained by immunogold labelling with anti-DNA antibodies. Anti-DNA antibodies heavily labelled the dense chromatin of the FCs but scarcely labelled the LFM. However, electron microscopic in situ hybridization using the 18S rDNA probe showed that the label in the dense chromatin was extremely weak compared with that obtained by the anti-DNA antibody labelling: the specific label with anti-DNA antibodies of the dense chromatin was about 15 times as much as that of the LFM, whereas the specific label with in situ hybridization in the dense chromatin was only about 1.7 times higher than in the LFM. These results suggest that the rDNA encoding rRNA is preferentially released from the dense chromatin and that non-transcribed intergenic spacers remain in the dense chromatin as the anchoring sites of rDNA. PMID:12227553

  7. Appraisal of selected osmoprotectants and carriers for formulating Gram-negative biocontrol agents active against Fusarium dry rot on potatoes in storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The production of a dry formulation containing a high titer of viable cells of a Gram-negative biological control agent is a challenging and critically important step in developing the agent into a commercial product. Producing a dry formulation using methods based on air-drying is especially attrac...

  8. Potential evapotranspiration and continental drying

    NASA Astrophysics Data System (ADS)

    Milly, P. C. D.; Dunne, K. A.

    2016-10-01

    By various measures (drought area and intensity, climatic aridity index, and climatic water deficits), some observational analyses have suggested that much of the Earth’s land has been drying during recent decades, but such drying seems inconsistent with observations of dryland greening and decreasing pan evaporation. `Offline’ analyses of climate-model outputs from anthropogenic climate change (ACC) experiments portend continuation of putative drying through the twenty-first century, despite an expected increase in global land precipitation. A ubiquitous increase in estimates of potential evapotranspiration (PET), driven by atmospheric warming, underlies the drying trends, but may be a methodological artefact. Here we show that the PET estimator commonly used (the Penman-Monteith PET for either an open-water surface or a reference crop) severely overpredicts the changes in non-water-stressed evapotranspiration computed in the climate models themselves in ACC experiments. This overprediction is partially due to neglect of stomatal conductance reductions commonly induced by increasing atmospheric CO2 concentrations in climate models. Our findings imply that historical and future tendencies towards continental drying, as characterized by offline-computed runoff, as well as other PET-dependent metrics, may be considerably weaker and less extensive than previously thought.

  9. Biological Oceanography

    NASA Technical Reports Server (NTRS)

    Abbott, M. R.

    1984-01-01

    Within the framework of global biogeochemical cycles and ocean productivity, there are two areas that will be of particular interest to biological oceanography in the 1990s. The first is the mapping in space time of the biomass and productivity of phytoplankton in the world ocean. The second area is the coupling of biological and physical processes as it affects the distribution and growth rate of phytoplankton biomass. Certainly other areas will be of interest to biological oceanographers, but these two areas are amenable to observations from satellites. Temporal and spatial variability is a regular feature of marine ecosystems. The temporal and spatial variability of phytoplankton biomass and productivity which is ubiquitous at all time and space scales in the ocean must be characterized. Remote sensing from satellites addresses these problems with global observations of mesocale (2 to 20 days, 10 to 200 km) features over a long period of time.

  10. Biological preconcentrator

    DOEpatents

    Manginell, Ronald P.; Bunker, Bruce C.; Huber, Dale L.

    2008-09-09

    A biological preconcentrator comprises a stimulus-responsive active film on a stimulus-producing microfabricated platform. The active film can comprise a thermally switchable polymer film that can be used to selectively absorb and desorb proteins from a protein mixture. The biological microfabricated platform can comprise a thin membrane suspended on a substrate with an integral resistive heater and/or thermoelectric cooler for thermal switching of the active polymer film disposed on the membrane. The active polymer film can comprise hydrogel-like polymers, such as poly(ethylene oxide) or poly(n-isopropylacrylamide), that are tethered to the membrane. The biological preconcentrator can be fabricated with semiconductor materials and technologies.

  11. Biological monitoring

    SciTech Connect

    Miller, S.

    1984-06-01

    Recent research is reviewed from books, international committees and symposia which describes the usefulness of biological monitoring for exposure to such compounds as organometallic chemicals, carbon monoxide and cyanide. The types of analyses include the following measurements: the concentration of the chemical in various biological media such as blood, urine, and expired air; the concentration of metabolites of the individual chemical in the same media; and determination of nonadverse biological changes resulting from the reaction of the organism to exposure. A main goal of such monitoring is to ensure that the current or past levels of worker exposure are safe, so that such exposure does not involve an unacceptable health risk. It considers routes other than absorption by the lungs and is a good method for evaluating individual exposures.

  12. Fragmentation of drying paint layers

    NASA Astrophysics Data System (ADS)

    Bakos, Katinka; Dombi, András; Járai-Szabó, Ferenc; Néda, Zoltán

    2013-11-01

    Fragmentation of thin layers of drying granular materials on a frictional surface are studied both by experiments and computer simulations. Besides a qualitative description of the fragmentation phenomenon, the dependence of the average fragment size as a function of the layer thickness is thoroughly investigated. Experiments are done using a special nail polish, which forms characteristic crack structures during drying. In order to control the layer thickness, we diluted the nail polish in acetone and evaporated in a controlled manner different volumes of this solution on glass surfaces. During the evaporation process we managed to get an instable paint layer, which formed cracks as it dried out. In order to understand the obtained structures a previously developed spring-block model was implemented in a three-dimensional version. The experimental and simulation results proved to be in excellent qualitative and quantitative agreement. An earlier suggested scaling relation between the average fragment size and the layer thickness is reconfirmed.

  13. Biological rhythms

    NASA Technical Reports Server (NTRS)

    Halberg, F.

    1975-01-01

    An overview is given of basic features of biological rhythms. The classification of periodic behavior of physical and psychological characteristics as circadian, circannual, diurnal, and ultradian is discussed, and the notion of relativistic time as it applies in biology is examined. Special attention is given to circadian rhythms which are dependent on the adrenocortical cycle. The need for adequate understanding of circadian variations in the basic physiological indicators of an individual (heart rate, body temperature, systolic and diastolic blood pressure, etc.) to ensure the effectiveness of prophylactic and therapeutic measures is stressed.

  14. A novel approach to sterile pharmaceutical freeze-drying.

    PubMed

    Cherry, Christopher Lee Albert; Millward, Huw; Cooper, Rose; Landon, John

    2014-02-01

    A novel approach has been developed that enables sterile pharmaceutical products to be freeze-dried in the open laboratory without specialist facilities. The product is filled into vials, semi-stoppered and sealed inside one, followed by a second, sterilization pouch under class 100 conditions. The product is then freeze-dried in the laboratory where the vials are shelf-stoppered before being returned to class 100, unwrapped and crimped. The sterilization pouches increased the resistance to water vapor movement during sublimation, thereby increasing the sublimation time and product temperature. Ovine immunoglobulins were double wrapped and lyophilized (as above) adjusting the primary drying time and shelf temperature for increased product temperature and, therefore, prevention of collapse. Ovine immunoglobulin G formulations freeze-dried to ≤ 1.1% residual moisture with no effect on protein aggregation or biological activity. The process was simulated with tryptone soya broth and no growth of contaminating microbial cells was observed after incubation at 35 °C for 2 weeks. Although increasing lyophilization time, this approach offers significant plant and validation cost savings when sterile freeze-drying small numbers of vials thereby making the manufacture of treatments for neglected and orphan diseases more viable economically.

  15. Cardiovascular and renal benefits of dry bean and soybean intake.

    PubMed

    Anderson, J W; Smith, B M; Washnock, C S

    1999-09-01

    Dry beans and soybeans are nutrient-dense, fiber-rich, and are high-quality sources of protein. Protective and therapeutic effects of both dry bean and soybean intake have been documented. Studies show that dry bean intake has the potential to decrease serum cholesterol concentrations, improve many aspects of the diabetic state, and provide metabolic benefits that aid in weight control. Soybeans are a unique source of the isoflavones genistein and diadzein, which have numerous biological functions. Soybeans and soyfoods potentially have multifaceted health-promoting effects, including cholesterol reduction, improved vascular health, preserved bone mineral density, and reduction of menopausal symptoms. Soy appears to have salutary effects on renal function, although these effects are not well understood. Whereas populations consuming high intakes of soy have lower prevalences of certain cancers, definitive experimental data are insufficient to clarify a protective role of soy. The availability of legume products and resources is increasing, incorporating dry beans and soyfoods into the diet can be practical and enjoyable. With the shift toward a more plant-based diet, dry beans and soy will be potent tools in the treatment and prevention of chronic disease. PMID:10479219

  16. Freeze-dried microarterial allografts

    SciTech Connect

    Raman, J.; Hargrave, J.C.

    1990-02-01

    Rehydrated freeze-dried microarterial allografts were implanted to bridge arterial defects using New Zealand White rabbits as the experimental model. Segments of artery from the rabbit ear and thigh were harvested and preserved for a minimum of 2 weeks after freeze-drying. These allografts, approximately 1 mm in diameter and ranging from 1.5 to 2.5 cm in length, were rehydrated and then implanted in low-pressure and high-pressure arterial systems. Poor patency was noted in low-pressure systems in both allografts and autografts, tested in 12 rabbits. In the high-pressure arterial systems, allografts that were freeze-dried and reconstituted failed in a group of 10 rabbits with an 8-week patency rate of 30 percent. Gamma irradiation in an effort to reduce infection and antigenicity of grafts after freeze-drying was associated with a patency rate of 10 percent at 8 weeks in this system in another group of 10 rabbits. Postoperative cyclosporin A therapy was associated with a patency rate of 22.2 percent in the high-pressure arterial system in a 9-rabbit group. Control autografts in this system in a group of 10 rabbits showed a 100 percent patency at 8 weeks. Microarterial grafts depend on perfusion pressure of the vascular bed for long-term patency. Rehydrated freeze-dried microarterial allografts do not seem to function well in lengths of 1 to 2.5 cm when implanted in a high-pressure arterial system. Freeze-dried arterial allografts are probably not antigenic.

  17. Optimization of drying process parameters for cauliflower drying.

    PubMed

    Gupta, Manoj Kumar; Sehgal, V K; Arora, Sadhna

    2013-02-01

    The different sizes (3, 4 and 5 cm) of hybrid variety of cauliflower (variety no. 71) were dehydrated in thin layer at three temperatures of 55, 60 and 65 °C with velocities of 40, 50 and 60 m/min. Dehydrated samples were analyzed for vitamin C, rehydration ratio and browning. Statistical analysis indicated that drying time was dependent on initial size of cauliflower, drying air temperature and velocity, but rehydration ratio was significantly affected by the combined effect of temperature and airflow velocity. Vitamin C content of the dried cauliflower samples were significantly affected by temperature only and non enzymatic browning was function of temperature, airflow velocity, and combined effect of temperature and airflow velocity. Optimization of the drying process parameters for the given constraints resulted in 60.10(0)C, 59.28 m/min, 3.35 cm. The predicted responses for the optimized combination of process parameters were time, vitamin C content, rehydration ratio, and browning values of 491.22 min (time), 289.86 mg/100 g (Vitamin C), 6.91 ( rehydration ratio), and 0.14 (browning), respectively with the desirability factor of 0.787. PMID:24425888

  18. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  19. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  20. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  1. 21 CFR 172.896 - Dried yeasts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Dried yeasts. 172.896 Section 172.896 Food and... Multipurpose Additives § 172.896 Dried yeasts. Dried yeast (Saccharomyces cerevisiae and Saccharomyces fragilis) and dried torula yeast (Candida utilis) may be safely used in food provided the total folic...

  2. 7 CFR 58.409 - Drying room.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Drying room. 58.409 Section 58.409 Agriculture....409 Drying room. When applicable, a drying room of adequate size shall be provided to accommodate the... provided for proper drying. Temperature and humidity control facilities should be provided which...

  3. 7 CFR 58.409 - Drying room.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Drying room. 58.409 Section 58.409 Agriculture....409 Drying room. When applicable, a drying room of adequate size shall be provided to accommodate the... provided for proper drying. Temperature and humidity control facilities should be provided which...

  4. 7 CFR 58.409 - Drying room.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Drying room. 58.409 Section 58.409 Agriculture....409 Drying room. When applicable, a drying room of adequate size shall be provided to accommodate the... provided for proper drying. Temperature and humidity control facilities should be provided which...

  5. 7 CFR 58.409 - Drying room.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Drying room. 58.409 Section 58.409 Agriculture....409 Drying room. When applicable, a drying room of adequate size shall be provided to accommodate the... provided for proper drying. Temperature and humidity control facilities should be provided which...

  6. 7 CFR 58.409 - Drying room.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Drying room. 58.409 Section 58.409 Agriculture....409 Drying room. When applicable, a drying room of adequate size shall be provided to accommodate the... provided for proper drying. Temperature and humidity control facilities should be provided which...

  7. 7 CFR 58.813 - Dry whey.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Dry whey. 58.813 Section 58.813 Agriculture... Products Bearing Usda Official Identification § 58.813 Dry whey. The quality requirements for dry whey shall be in accordance with the U.S. Standards for Dry Whey. Supplemental Specifications for...

  8. The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis.

    PubMed

    Xu, Shu-Jun; Liu, Chun-Jiang; Jiang, Ping-An; Cai, Wei-Min; Wang, Yan

    2009-03-15

    Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 degrees C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 degrees C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs.

  9. Stabilized dried blood spot collection.

    PubMed

    McMorran, Darren; Chung, Dwayne Chung Kim; Toth, Monika; Liew, Oi Wah; Muradoglu, Murat; Ng, Tuck Wah

    2016-08-01

    During the collection phase of the dried blood spot method, practitioners need to ensure that there is no smearing of the blood sample on the filter paper or else readings from it will be invalid. This can be difficult to accomplish in the field if there is relative motion between the site of blood discharge on the finger and the filter paper. In this article, a gyroscope stabilization method is introduced and demonstrated to provide consistent and improved dried blood spot collection within a circular guide region notwithstanding the presence of rocking. PMID:27156813

  10. Fundamentals of freeze-drying.

    PubMed

    Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

    2002-01-01

    Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction

  11. Scaffolded biology.

    PubMed

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology. PMID:27287514

  12. Bottle Biology.

    ERIC Educational Resources Information Center

    Jager, Peter

    1993-01-01

    Describes activities which utilize plastic drink bottles and are designed to foster the development of a wide range of biological and ecological concepts. Includes instructions for making a model compost column and presents a model that illustrates open versus closed ecosystems. (DDR)

  13. Biologic Vaccines

    PubMed Central

    ADAMS, KATHERINE T.

    2009-01-01

    The threat of new disease pandemics has spurred the development of biologic vaccines, which promise tremendous improvements in global and local health. Several lend themselves to the prevention or treatment of chronic diseases. But the uncertainties of whom to vaccinate raise the question of whether the health care system can make these promising products viable. PMID:22478749

  14. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1979

    1979-01-01

    Organized by topic is a reading list for A- and S-level biology. Described are experiments for measuring rate of water uptake in a shoot; questions to aid students in designing experiments; rise of overhead projection to demonstrate osmosis and blood cell counting; and microbial manufacture of vinegar. (CS)

  15. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1980

    1980-01-01

    Describes equipment, activities, and experiments useful in biology and environmental education instruction, including, among others, sampling in ecology using an overhead projector, the slide finder as an aid to microscopy, teaching kidney function, and teaching wildlife conservation-sand dune systems. (SK)

  16. Biology Notes

    ERIC Educational Resources Information Center

    School Science Review, 1976

    1976-01-01

    Describes nine biology experiments, including osmosis, genetics; oxygen content of blood, enzymes in bean seedlings, preparation of bird skins, vascularization in bean seedlings, a game called "sequences" (applied to review situations), crossword puzzle for human respiration, and physiology of the woodlouse. (CS)

  17. Scaffolded biology.

    PubMed

    Minelli, Alessandro

    2016-09-01

    Descriptions and interpretations of the natural world are dominated by dichotomies such as organism vs. environment, nature vs. nurture, genetic vs. epigenetic, but in the last couple of decades strong dissatisfaction with those partitions has been repeatedly voiced and a number of alternative perspectives have been suggested, from perspectives such as Dawkins' extended phenotype, Turner's extended organism, Oyama's Developmental Systems Theory and Odling-Smee's niche construction theory. Last in time is the description of biological phenomena in terms of hybrids between an organism (scaffolded system) and a living or non-living scaffold, forming unit systems to study processes such as reproduction and development. As scaffold, eventually, we can define any resource used by the biological system, especially in development and reproduction, without incorporating it as happens in the case of resources fueling metabolism. Addressing biological systems as functionally scaffolded systems may help pointing to functional relationships that can impart temporal marking to the developmental process and thus explain its irreversibility; revisiting the boundary between development and metabolism and also regeneration phenomena, by suggesting a conceptual framework within which to investigate phenomena of regular hypermorphic regeneration such as characteristic of deer antlers; fixing a periodization of development in terms of the times at which a scaffolding relationship begins or is terminated; and promoting plant galls to legitimate study objects of developmental biology.

  18. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1983

    1983-01-01

    Describes laboratory procedures, demonstrations, and classroom activities/materials, including water relation exercise on auxin-treated artichoke tuber tissue; aerobic respiration in yeast; an improved potometer; use of mobiles in biological classification, and experiments on powdery mildews and banana polyphenol oxidase. Includes reading lists…

  19. (Biological dosimetry)

    SciTech Connect

    Preston, R.J.

    1990-12-17

    The traveler attended the 1st International Conference on Biological Dosimetry in Madrid, Spain. This conference was organized to provide information to a general audience of biologists, physicists, radiotherapists, industrial hygiene personnel and individuals from related fields on the current ability of cytogenetic analysis to provide estimates of radiation dose in cases of occupational or environmental exposure. There is a growing interest in Spain in biological dosimetry because of the increased use of radiation sources for medical and occupational uses, and with this the anticipated and actual increase in numbers of overexposure. The traveler delivered the introductory lecture on Biological Dosimetry: Mechanistic Concepts'' that was intended to provide a framework by which the more applied lectures could be interpreted in a mechanistic way. A second component of the trip was to provide advice with regard to several recent cases of overexposure that had been or were being assessed by the Radiopathology and Radiotherapy Department of the Hospital General Gregorio Maranon'' in Madrid. The traveler had provided information on several of these, and had analyzed cells from some exposed or purportedly exposed individuals. The members of the biological dosimetry group were referred to individuals at REACTS at Oak Ridge Associated Universities for advice on follow-up treatment.

  20. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Outlines a variety of laboratory procedures, techniques, and materials including construction of a survey frame for field biology, a simple tidal system, isolation and applications of plant protoplasts, tropisms, teaching lung structure, and a key to statistical methods for biologists. (DS)

  1. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1981

    1981-01-01

    Presents content information and/or laboratory procedures and experiments on different biology topics including small-scale cultivation of watercress and its use in water-culture experiments, microbiology of the phylloplane, use of mouthbrooders in science class, and the gene. (DC)

  2. Biology Notes.

    ERIC Educational Resources Information Center

    School Science Review, 1984

    1984-01-01

    Presents information on the teaching of nutrition (including new information relating to many current O-level syllabi) and part 16 of a reading list for A- and S-level biology. Also includes a note on using earthworms as a source of material for teaching meiosis. (JN)

  3. Sverdrup's Biology

    NASA Astrophysics Data System (ADS)

    McGowan, J.

    2002-12-01

    Sverdrup's contribution to Biological Oceanography were more than merely substantial, they were of fundamental importance. His plan for the training of graduate students at Scripps did not recognize the traditional division of the basic disciplines into separate categories of physics, chemistry, biology and geology. He insisted that Oceanography was a multi-disciplinary subject and that all entering students should study all four subjects. Today this is not very unusual but it was in the early 50s when I took those courses. We biologists carried away from those courses an appreciation of the importance of both spatial and temporal scale. It was of clear relevance to problems of oceanic population and community biology. But there was still more to his biology. He is responsible for a very simple, but very elegant model of the regulation of oceanic primary productivity. The elements of this model are found today in the ten or so highly derivative models. He also published a map predicting global ocean productivity based on the ideas in the model plus some wonderfully intuitive thinking. This map does not differ strongly from those glorious false color ones being published today.

  4. Marine Biology

    ERIC Educational Resources Information Center

    Dewees, Christopher M.; Hooper, Jon K.

    1976-01-01

    A variety of informational material for a course in marine biology or oceanology at the secondary level is presented. Among the topics discussed are: food webs and pyramids, planktonic blooms, marine life, plankton nets, food chains, phytoplankton, zooplankton, larval plankton and filter feeders. (BT)

  5. Cancer Biology

    ERIC Educational Resources Information Center

    Dominiecki, Mary E.

    2004-01-01

    University of Colorado's Virtual Student Fellowship available at and developed by Bakemeier, Richard F. This website is designed to give students applying for a fellowship an overview of basic topics in biology and how they are used by cancer researchers to develop new treatments.

  6. Dry machinability of aluminum alloys.

    SciTech Connect

    Shareef, I.; Natarajan, M.; Ajayi, O. O.; Energy Technology; Department of IMET

    2005-01-01

    Adverse effects of the use of cutting fluids and environmental concerns with regard to cutting fluid disposability is compelling industry to adopt Dry or near Dry Machining, with the aim of eliminating or significantly reducing the use of metal working fluids. Pending EPA regulations on metal cutting, dry machining is becoming a hot topic of research and investigation both in industry and federal research labs. Although the need for dry machining may be apparent, most of the manufacturers still consider dry machining to be impractical and even if possible, very expensive. This perception is mainly due to lack of appropriate cutting tools that can withstand intense heat and Built-up-Edge (BUE) formation during dry machining. The challenge of heat dissipation without coolant requires a completely different approach to tooling. Special tooling utilizing high-performance multi-layer, multi-component, heat resisting, low friction coatings could be a plausible answer to the challenge of dry machining. In pursuit of this goal Argonne National Labs has introduced Nano-crystalline near frictionless carbon (NFC) diamond like coatings (DLC), while industrial efforts have led to the introduction of composite coatings such as titanium aluminum nitride (TiAlN), tungsten carbide/carbon (WC/C) and others. Although, these coatings are considered to be very promising, they have not been tested either from tribological or from dry machining applications point of view. As such a research program in partnership with federal labs and industrial sponsors has started with the goal of exploring the feasibility of dry machining using the newly developed coatings such as Near Frictionless Carbon Coatings (NFC), Titanium Aluminum Nitride (TiAlN), and multi-layer multicomponent nano coatings such as TiAlCrYN and TiAlN/YN. Although various coatings are under investigation as part of the overall dry machinability program, this extended abstract deals with a systematic investigation of dry

  7. Energy and quality aspects of food drying

    SciTech Connect

    Strumillo, C.; Adamiec, J.

    1996-05-01

    High energy consumption and increasing consumers` interest in new products are two problems worthy of note in the drying of food. Difficulties in producing high-quality food and degrading transformations of the material during drying are mentioned. The kinetics of quality degradation due to drying is described. The role of water activity in maintaining product quality is emphasized. Examples of drying methods and tendencies toward a reduction in quality degradation of dried food products are shown.

  8. THE DIRT ON DRY MERGERS

    SciTech Connect

    Desai, Vandana; Soifer, B. T.; Dey, Arjun; Cohen, Emma; Le Floc'h, Emeric

    2011-04-01

    Using data from the Spitzer Space Telescope, we analyze the mid-infrared (3-70 {mu}m) spectral energy distributions of dry merger candidates in the Booetes field of the NOAO Deep Wide-Field Survey. These candidates were selected by previous authors to be luminous, red, early-type galaxies with morphological evidence of recent tidal interactions. We find that a significant fraction of these candidates exhibit 8 and 24 {mu}m excesses compared to expectations for old stellar populations. We estimate that a quarter of dry merger candidates have mid-infrared-derived star formation rates greater than {approx}1 M{sub sun} yr{sup -1}. This represents a 'frosting' on top of a large old stellar population, and has been seen in previous studies of elliptical galaxies. Further, the dry merger candidates include a higher fraction of star-forming galaxies relative to a control sample without tidal features. We therefore conclude that the star formation in these massive ellipticals is likely triggered by merger activity. Our data suggest that the mergers responsible for the observed tidal features were not completely dry, and may be minor mergers involving a gas-rich dwarf galaxy.

  9. Longevity Of Dry Film Lubricants

    NASA Technical Reports Server (NTRS)

    Kannel, J. W.; Stockwell, R. D.

    1993-01-01

    Report describes evaluation of dry film lubricants candidate for use in rotary joints of proposed Space Station. Study included experiments and theoretical analyses focused on longevity of sputtered molybdenum disulfide films and ion-plated lead films under conditions partially simulating rolling contact.

  10. Microwave drying of seed cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A small lab dryer was designed for use in drying seed cotton with components of a microwave generator mounted thereon. The magnetron emitted radiation directly into the seed cotton and a fan directed air cross-flow to the radiation direction. The microwave components were a 1.1 kW magnetron, trans...

  11. Drying Milk With Boiler Exhaust

    NASA Technical Reports Server (NTRS)

    Broussard, M. R.

    1984-01-01

    Considerable energy saved in powdered-milk industry. Only special requirement boiler fired with natural gas or other clean fuel. Boiler flue gas fed to spray drier where it directly contacts product to be dried. Additional heat supplied by auxillary combustor when boiler output is low. Approach adaptable to existing plants with minimal investment because most already equipped with natural-gas-fired boilers.

  12. IKK Biology

    PubMed Central

    Liu, Fei; Xia, Yifeng; Parker, Aaron S.; Verma, Inder M.

    2012-01-01

    Summary The inhibitor of nuclear factor-κB (IκB) kinase (IKK) complex is the master regulator of the NF-κB signaling pathway. The activation of the IKK complex is a tightly regulated, highly stimulus-specific, and target-specific event that is essential for the plethora of functions attributed to NF-κB. More recently, NF-κB independent roles of IKK members have brought increased complexity to its biological function. This review highlights some of the major advances in the studies of the process of IKK activation and the biological roles of IKK family members, with a focus on NF-κB independent functions. Understanding these complex processes is essential for targeting IKK for therapeutics. PMID:22435559

  13. Crusts: biological

    USGS Publications Warehouse

    Belnap, Jayne; Elias, Scott A.

    2013-01-01

    Biological soil crusts, a community of cyanobacteria, lichens, mosses, and fungi, are an essential part of dryland ecosystems. They are critical in the stabilization of soils, protecting them from wind and water erosion. Similarly, these soil surface communities also stabilized soils on early Earth, allowing vascular plants to establish. They contribute nitrogen and carbon to otherwise relatively infertile dryland soils, and have a strong influence on hydrologic cycles. Their presence can also influence vascular plant establishment and nutrition.

  14. Curcumin Ameliorates the Reduction Effect of PGE2 on Fibrillar β-Amyloid Peptide (1-42)-Induced Microglial Phagocytosis through the Inhibition of EP2-PKA Signaling in N9 Microglial Cells

    PubMed Central

    Yang, Ju; Shen, Ting-ting; Chen, Yi; Yang, Xue-Sen

    2016-01-01

    Inflammatory activation of microglia and β amyloid (Aβ) deposition are considered to work both independently and synergistically to contribute to the increased risk of Alzheimer’s disease (AD). Recent studies indicate that long-term use of phenolic compounds provides protection against AD, primarily due to their anti-inflammatory actions. We previously suggested that phenolic compound curcumin ameliorated phagocytosis possibly through its anti-inflammatory effects rather than direct regulation of phagocytic function in electromagnetic field-exposed N9 microglial cells (N9 cells). Here, we explored the prostaglandin-E2 (PGE2)-related signaling pathway that involved in curcumin-mediated phagocytosis in fibrillar β-amyloid peptide (1–42) (fAβ42)-stimulated N9 cells. Treatment with fAβ42 increased phagocytosis of fluorescent-labeled latex beads in N9 cells. This increase was attenuated in a dose-dependent manner by endogenous and exogenous PGE2, as well as a selective EP2 or protein kinase A (PKA) agonist, but not by an EP4 agonist. We also found that an antagonist of EP2, but not EP4, abolished the reduction effect of PGE2 on fAβ42-induced microglial phagocytosis. Additionally, the increased expression of endogenous PGE2, EP2, and cyclic adenosine monophosphate (AMP), and activation of vasodilator-stimulated phosphoprotein, cyclic AMP responsive element-binding protein, and PKA were depressed by curcumin administration. This reduction led to the amelioration of the phagocytic abilities of PGE2-stimulated N9 cells. Taken together, these data suggested that curcumin restored the attenuating effect of PGE2 on fAβ42-induced microglial phagocytosis via a signaling mechanism involving EP2 and PKA. Moreover, due to its immune modulatory effects, curcumin may be a promising pharmacological candidate for neurodegenerative diseases. PMID:26824354

  15. Zn(II)- and Cu(II)-induced non-fibrillar aggregates of amyloid-beta (1-42) peptide are transformed to amyloid fibrils, both spontaneously and under the influence of metal chelators.

    PubMed

    Tõugu, Vello; Karafin, Ann; Zovo, Kairit; Chung, Roger S; Howells, Claire; West, Adrian K; Palumaa, Peep

    2009-09-01

    Aggregation of amyloid-beta (Abeta) peptides is a central phenomenon in Alzheimer's disease. Zn(II) and Cu(II) have profound effects on Abeta aggregation; however, their impact on amyloidogenesis is unclear. Here we show that Zn(II) and Cu(II) inhibit Abeta(42) fibrillization and initiate formation of non-fibrillar Abeta(42) aggregates, and that the inhibitory effect of Zn(II) (IC(50) = 1.8 micromol/L) is three times stronger than that of Cu(II). Medium and high-affinity metal chelators including metallothioneins prevented metal-induced Abeta(42) aggregation. Moreover, their addition to preformed aggregates initiated fast Abeta(42) fibrillization. Upon prolonged incubation the metal-induced aggregates also transformed spontaneously into fibrils, that appear to represent the most stable state of Abeta(42). H13A and H14A mutations in Abeta(42) reduced the inhibitory effect of metal ions, whereas an H6A mutation had no significant impact. We suggest that metal binding by H13 and H14 prevents the formation of a cross-beta core structure within region 10-23 of the amyloid fibril. Cu(II)-Abeta(42) aggregates were neurotoxic to neurons in vitro only in the presence of ascorbate, whereas monomers and Zn(II)-Abeta(42) aggregates were non-toxic. Disturbed metal homeostasis in the vicinity of zinc-enriched neurons might pre-dispose formation of metal-induced Abeta aggregates, subsequent fibrillization of which can lead to amyloid formation. The molecular background underlying metal-chelating therapies for Alzheimer's disease is discussed in this light. PMID:19619132

  16. Curcumin Ameliorates the Reduction Effect of PGE2 on Fibrillar β-Amyloid Peptide (1-42)-Induced Microglial Phagocytosis through the Inhibition of EP2-PKA Signaling in N9 Microglial Cells.

    PubMed

    He, Gen-Lin; Luo, Zhen; Yang, Ju; Shen, Ting-Ting; Chen, Yi; Yang, Xue-Sen

    2016-01-01

    Inflammatory activation of microglia and β amyloid (Aβ) deposition are considered to work both independently and synergistically to contribute to the increased risk of Alzheimer's disease (AD). Recent studies indicate that long-term use of phenolic compounds provides protection against AD, primarily due to their anti-inflammatory actions. We previously suggested that phenolic compound curcumin ameliorated phagocytosis possibly through its anti-inflammatory effects rather than direct regulation of phagocytic function in electromagnetic field-exposed N9 microglial cells (N9 cells). Here, we explored the prostaglandin-E2 (PGE2)-related signaling pathway that involved in curcumin-mediated phagocytosis in fibrillar β-amyloid peptide (1-42) (fAβ42)-stimulated N9 cells. Treatment with fAβ42 increased phagocytosis of fluorescent-labeled latex beads in N9 cells. This increase was attenuated in a dose-dependent manner by endogenous and exogenous PGE2, as well as a selective EP2 or protein kinase A (PKA) agonist, but not by an EP4 agonist. We also found that an antagonist of EP2, but not EP4, abolished the reduction effect of PGE2 on fAβ42-induced microglial phagocytosis. Additionally, the increased expression of endogenous PGE2, EP2, and cyclic adenosine monophosphate (AMP), and activation of vasodilator-stimulated phosphoprotein, cyclic AMP responsive element-binding protein, and PKA were depressed by curcumin administration. This reduction led to the amelioration of the phagocytic abilities of PGE2-stimulated N9 cells. Taken together, these data suggested that curcumin restored the attenuating effect of PGE2 on fAβ42-induced microglial phagocytosis via a signaling mechanism involving EP2 and PKA. Moreover, due to its immune modulatory effects, curcumin may be a promising pharmacological candidate for neurodegenerative diseases.

  17. Curcumin Ameliorates the Reduction Effect of PGE2 on Fibrillar β-Amyloid Peptide (1-42)-Induced Microglial Phagocytosis through the Inhibition of EP2-PKA Signaling in N9 Microglial Cells.

    PubMed

    He, Gen-Lin; Luo, Zhen; Yang, Ju; Shen, Ting-Ting; Chen, Yi; Yang, Xue-Sen

    2016-01-01

    Inflammatory activation of microglia and β amyloid (Aβ) deposition are considered to work both independently and synergistically to contribute to the increased risk of Alzheimer's disease (AD). Recent studies indicate that long-term use of phenolic compounds provides protection against AD, primarily due to their anti-inflammatory actions. We previously suggested that phenolic compound curcumin ameliorated phagocytosis possibly through its anti-inflammatory effects rather than direct regulation of phagocytic function in electromagnetic field-exposed N9 microglial cells (N9 cells). Here, we explored the prostaglandin-E2 (PGE2)-related signaling pathway that involved in curcumin-mediated phagocytosis in fibrillar β-amyloid peptide (1-42) (fAβ42)-stimulated N9 cells. Treatment with fAβ42 increased phagocytosis of fluorescent-labeled latex beads in N9 cells. This increase was attenuated in a dose-dependent manner by endogenous and exogenous PGE2, as well as a selective EP2 or protein kinase A (PKA) agonist, but not by an EP4 agonist. We also found that an antagonist of EP2, but not EP4, abolished the reduction effect of PGE2 on fAβ42-induced microglial phagocytosis. Additionally, the increased expression of endogenous PGE2, EP2, and cyclic adenosine monophosphate (AMP), and activation of vasodilator-stimulated phosphoprotein, cyclic AMP responsive element-binding protein, and PKA were depressed by curcumin administration. This reduction led to the amelioration of the phagocytic abilities of PGE2-stimulated N9 cells. Taken together, these data suggested that curcumin restored the attenuating effect of PGE2 on fAβ42-induced microglial phagocytosis via a signaling mechanism involving EP2 and PKA. Moreover, due to its immune modulatory effects, curcumin may be a promising pharmacological candidate for neurodegenerative diseases. PMID:26824354

  18. Marine biology

    SciTech Connect

    Thurman, H.V.; Webber, H.H.

    1984-01-01

    This book discusses both taxonomic and ecological topics on marine biology. Full coverage of marine organisms of all five kingdoms is provided, along with interesting and thorough discussion of all major marine habitats. Organization into six major parts allows flexibility. It also provides insight into important topics such as disposal of nuclear waste at sea, the idea that life began on the ocean floor, and how whales, krill, and people interact. A full-color photo chapter reviews questions, and exercises. The contents are: an overview marine biology: fundamental concepts/investigating life in the ocean; the physical ocean, the ocean floor, the nature of water, the nature and motion of ocean water; general ecology, conditions for life in the sea, biological productivity and energy transfer; marine organisms; monera, protista, mycota and metaphyta; the smaller marine animals, the large animals marine habitats, the intertidal zone/benthos of the continental shelf, the photic zone, the deep ocean, the ocean under stress, marine pollution, appendix a: the metric system and conversion factors/ appendix b: prefixes and suffixes/ appendix c: taxonomic classification of common marine organisms, and glossary, and index.

  19. The Production of a Stable Infliximab Powder: The Evaluation of Spray and Freeze-Drying for Production

    PubMed Central

    Kanojia, Gaurav; Have, Rimko ten; Bakker, Arjen; Wagner, Koen; Frijlink, Henderik W.; Kersten, Gideon F. A.; Amorij, Jean-Pierre

    2016-01-01

    In prospect of developing an oral dosage form of Infliximab, for treatment of Crohn’s disease and rheumatoid arthritis, freeze-drying (vial vs Lyoguard trays) and spray-drying were investigated as production method for stable powders. Dextran and inulin were used in combination with sucrose as stabilizing excipients. The drying processes did not affect Infliximab in these formulations, i.e. both the physical integrity and biological activity (TNF binding) were retained. Accelerated stability studies (1 month at 60°C) showed that the TNF binding ability of Infliximab was conserved in the freeze-dried formulations, whereas the liquid counterpart lost all TNF binding. After thermal treatment, the dried formulations showed some chemical modification of the IgG in the dextran-sucrose formulation, probably due to Maillard reaction products. This study indicates that, with the appropriate formulation, both spray-drying and freeze-drying may be useful for (bulk) powder production of Infliximab. PMID:27706175

  20. Electronic Nose Characterization of the Quality Parameters of Freeze-Dried Bacteria

    NASA Astrophysics Data System (ADS)

    Capuano, R.; Santonico, M.; Martinelli, E.; Paolesse, R.; Passot, S.; Fonseca, F.; Cenard, S.; Trelea, C.; Di Natale, C.

    2011-09-01

    Freeze-drying is the method of choice for preserving heat sensitive biological products such as microorganisms. The development of a fast analytical method for evaluating the properties of the dehydrated bacteria is then necessary for a proper utilization of the product in several food processes. In this paper, dried bacteria headspace is analyzed by a GC-MS and an electronic nose. Results indicate that headspace contains enough information to assess the products quality.

  1. Dried plums and their products: composition and health effects--an updated review.

    PubMed

    Stacewicz-Sapuntzakis, M

    2013-01-01

    This paper describes composition of dried plums and their products (prune juice and dried plum powder) with special attention to possibly bioactive compounds. Dried plums contain significant amounts of sorbitol, quinic acid, chlorogenic acids, vitamin K1, boron, copper, and potassium. Synergistic action of these and other compounds, which are also present in dried plums in less conspicuous amounts, may have beneficial health effects when dried plums are regularly consumed. Snacking on dried plums may increase satiety and reduce the subsequent intake of food, helping to control obesity, diabetes, and related cardiovascular diseases. Despite their sweet taste, dried plums do not cause large postprandial rise in blood glucose and insulin. Direct effects in the gastrointestinal tract include prevention of constipation and possibly colon cancer. The characteristic phenolic compounds and their metabolites may also act as antibacterial agents in both gastrointestinal and urinary tracts. The indirect salutary effects on bone turnover are supported by numerous laboratory studies with animals and cell cultures. Further investigation of phenolic compounds in dried plums, particularly of high molecular weight polymers, their metabolism and biological actions, alone and in synergy with other dried plum constituents, is necessary to elucidate the observed health effects and to indicate other benefits. PMID:24090144

  2. Magnetic field switchable dry adhesives.

    PubMed

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-01

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  3. Hydrodynamic model for drying emulsions.

    PubMed

    Feng, Huanhuan; Sprakel, Joris; van der Gucht, Jasper

    2015-08-01

    We present a hydrodynamic model for film formation in a dense oil-in-water emulsion under a unidirectional drying stress. Water flow through the plateau borders towards the drying end leads to the buildup of a pressure gradient. When the local pressure exceeds the critical disjoining pressure, the water films between droplets break and the droplets coalesce. We show that, depending on the critical pressure and the evaporation rate, the coalescence can occur in two distinct modes. At low critical pressures and low evaporation rates, coalescence occurs throughout the sample, whereas at high critical pressures and high evaporation rate, coalescence occurs only at the front. In the latter case, an oil layer develops on top of the film, which acts as a diffusive barrier and slows down film formation. Our findings, which are summarized in a state diagram for film formation, are in agreement with recent experimental findings.

  4. Drying of Beulah Zap lignite

    SciTech Connect

    Vorres, K.S.; Molenda, D. ); Dang, Y.; Malhotra, V.M. . Dept. of Physics)

    1991-01-01

    Recent results on the kinetics of water's desorption from Beulah-Zap lignite coal, as determined by thermogravimetric analysis (TGA) and the differential scanning calorimetry (DSC) technique were reported. The kinetic analysis of DSC was further complimented by determining the mechanism of air drying of lignite coal with the help of an in-situ Desorption Kinetics via Fourier transform infrared (ISDK-FTIR) technique. 17 refs., 5 figs., 1 tab.

  5. Combined Corex/DRI technology

    SciTech Connect

    Flickenschild, A.J.; Reufer, F.; Eberle, A.; Siuka, D.

    1996-08-01

    A feasible steelmaking alternative, the Corex/direct reduction/electric arc furnace combination, provides an economic route for the production of high quality steel products. This combination is a major step into a new generation of iron and steel mills. These mills are based on the production of liquid steel using noncoking coal and comply with the increasing demands of environmental protection. The favorable production costs are based on: Utilization of Corex and DRI/HBI plants; Production of hot metal equal to blast furnace quality; Use of low cost raw materials such as noncoking coal and lump ore; Use of process gas as reducing agent for DRI/HBI production; and Use of electric arc furnace with high hot metal input as the steelmaking process. The high flexibility of the process permits the adjustment of production in accordance with the strategy of the steel mills. New but proven technologies and applications of the latest state of art steelmaking process, e.g., Corex, in conjunction with DRI production as basic raw material for an electric arc furnace, will insure high quality, high availability, optimized energy generation at high efficiency rates, and high product quality for steelmaking.

  6. Solar drying in the Caribbean

    SciTech Connect

    Headley, O. )

    1992-03-01

    The United Nations Food and Agricultural Organisation (FAO) has estimated that a quarter of crops are lost through inadequate handling after harvesting. The use of solar dryers can reduce these losses and improve the quality of food. Oliver Headley of the University of the West Indies overviews a range of dryers developed in the Caribbean region. Solar dryers have been used in various parts of the Caribbean for the past eighteen years. The main types are: closed cycle dryers with separate flat plate collector; open cycle dryers with roof vanes against direct sunlight; open cycle dryers with rockbed heat storage units; open cycle dryers with chimneys for air circulation; wire basket dryers with flow through ventilation; barn roof collectors feeding packed bed dryers. During the dry season (January to April), mean daily insolation in a typical Caribbean island is about 25 MJ/m{sup 2}. With such an abundant resource, solar crop drying emerged as a preferred method for the preservation of perishable commodities. In territories without fossil fuel reserves solar energy is an obvious alternative since it does not involve expenditure of scarce foreign exchange. Research and development work in solar crop drying was conducted both at experimental sites in the University and in rural districts throughout the region. Several types of dryer were designed and tested.

  7. Accelerated dry curing of hams.

    PubMed

    Marriott, N G; Kelly, R F; Shaffer, C K; Graham, P P; Boling, J W

    1985-01-01

    Uncured pork legs from the right side of 18 carcasses were treated with a Ross Tenderizer and the left side were controls. All 36 samples were dry-cured for 40, 56 or 70 days and evaluated for appearance traits, cure penetration characteristics, microbial load, Kramer Shear force and taste attributes. The tenderization treatment had no effect (P > 0·05) on visual color or cure penetration rate, weight loss before curing, percentage moisture, nitrate level, nitrite level, total plate count, anaerobic counts, psychrotrophic counts, objective and subjective tenderness measurements or juiciness. However, the higher values of salt suggested a possible acceleration of the dry cure penetration process among the tenderized samples. Cure time had no effect (P > 0·05) on percentage moisture, percentage salt, nitrate content, nitrite content, shear force and juiciness. Results suggest a limited effect of the mechanical tenderization process on certain traits related to dry curing and that total process time should be at least 70 days if color stability during cooking is desired. PMID:22056076

  8. Ingested hyaluronan moisturizes dry skin

    PubMed Central

    2014-01-01

    Hyaluronan (HA) is present in many tissues of the body and is essential to maintain moistness in the skin tissues, which contain approximately half the body’s HA mass. Due to its viscosity and moisturizing effect, HA is widely distributed as a medicine, cosmetic, food, and, recently marketed in Japan as a popular dietary supplement to promote skin moisture. In a randomized, double-blind, placebo-controlled clinical study it was found that ingested HA increased skin moisture and improved treatment outcomes for patients with dry skin. HA is also reported to be absorbed by the body distributed, in part, to the skin. Ingested HA contributes to the increased synthesis of HA and promotes cell proliferation in fibroblasts. These effects show that ingestion of HA moisturizes the skin and is expected to improve the quality of life for people who suffer from dry skin. This review examines the moisturizing effects of dry skin by ingested HA and summarizes the series of mechanisms from absorption to pharmacological action. PMID:25014997

  9. Gaseous fuels production from dried sewage sludge via air gasification.

    PubMed

    Werle, Sebastian; Dudziak, Mariusz

    2014-07-01

    Gasification is a perspective alternative method of dried sewage sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed-bed gasifier installation was designed and built. Two sewage sludge (SS) feedstocks, taken from two typical Polish wastewater treatment systems, were analysed: SS1, from a mechanical-biological wastewater treatment system with anaerobic stabilization (fermentation) and high temperature drying; and (SS2) from a mechanical-biological-chemical wastewater treatment system with fermentation and low temperature drying. The gasification results show that greater oxygen content in sewage sludge has a strong influence on the properties of the produced gas. Increasing the air flow caused a decrease in the heating value of the produced gas. Higher hydrogen content in the sewage sludge (from SS1) affected the produced gas composition, which was characterized by high concentrations of combustible components. In the case of the SS1 gasification, ash, charcoal, and tar were produced as byproducts. In the case of SS2 gasification, only ash and tar were produced. SS1 and solid byproducts from its gasification (ash and charcoal) were characterized by lower toxicity in comparison to SS2. However, in all analysed cases, tar samples were toxic.

  10. Drying characteristics and quality of shiitake mushroom undergoing microwave-vacuum drying and microwave-vacuum combined with infrared drying.

    PubMed

    Kantrong, Hataichanok; Tansakul, Ampawan; Mittal, Gauri S

    2014-12-01

    Shiitake mushrooms were dehydrated by two different drying methods, i.e., microwave-vacuum drying (MVD) and microwave-vacuum combined with infrared drying (MVD + IR). MVD was operated at microwave powers of 56, 143, 209 and 267 W under absolute pressures of 18.66, 29.32, 39.99 and 50.65 kPa, whereas infrared radiation was added in MVD + IR at 100 and 200 W. The effects of microwave power, absolute pressure and infrared power on drying characteristics, qualities and specific energy consumption were investigated. It was found that drying rate increased with lower absolute pressure, higher microwave power and higher infrared power. In particular, the results also indicated that drying undergoing MVD + IR could provide better qualities in terms of color of dried shiitake mushroom, rehydration ratio and texture of rehydrated ones. Furthermore, the drying characteristics were described by fitting data to six different drying models. Based on their coefficient of determination, root mean square error, residual of sum square and chi-square, Modified Page model could accurately predict moisture ratio for all drying conditions. Within the range of this study, the suitable drying condition with respect to the product qualities and energy consumption was MVD + IR drying at 267 W of microwave power, 18.66 kPa of absolute pressure and 200 W of infrared power.

  11. Characterization of artificially dried biofilms for air biofiltration studies.

    PubMed

    Cercado, Bibiana; Auria, Richard; Cardenas, Beatriz; Revah, Sergio

    2012-01-01

    One of the main problems associated with the operation of air biofilters is the loss of performance caused by drying of the bioactive support, as the removal capacity of contaminants by the microorganisms is dependent on their water content. In this work, biofilms from a microbial consortium adapted to toluene were grown on stainless steel slides. The biofilms were dried in stoppered flasks with saturated saline solutions to obtain final water activities of 97.4 %, 83.9 %, 74.8 % and 32 %. The biofilms were characterized by a sorption isotherm Type III with toluene; the water desorption isotherm was fitted to the BET model and the biofilm hydrophobicity was also determined. Specific oxygen consumption rates decreased at lower Aw from 60 μg O(2)/mg protein/h to zero activity. Biofilm activity, represented by a toluene consumption rate, and others physical properties presented a critical point between Aw 0.84 and 0.97. Biological activity of dried biofilms was restored either partially or completely, depending on the extent of drying and rewetting method. PMID:22486663

  12. Drying and recovery of aerobic granules.

    PubMed

    Hu, Jianjun; Zhang, Quanguo; Chen, Yu-You; Lee, Duu-Jong

    2016-10-01

    To dehydrate aerobic granules to bone-dry form was proposed as a promising option for long-term storage of aerobic granules. This study cultivated aerobic granules with high proteins/polysaccharide ratio and then dried these granules using seven protocols: drying at 37°C, 60°C, 4°C, under sunlight, in dark, in a flowing air stream or in concentrated acetone solutions. All dried granules experienced volume shrinkage of over 80% without major structural breakdown. After three recovery batches, although with loss of part of the volatile suspended solids, all dried granules were restored most of their original size and organic matter degradation capabilities. The strains that can survive over the drying and storage periods were also identified. Once the granules were dried, they can be stored over long period of time, with minimal impact yielded by the applied drying protocols. PMID:27392096

  13. Simple Solutions for Treating Dry Mouth

    MedlinePlus

    Patient Education Sheet Simple Solutions for Treating Dry Mouth Clinicians: Please make as many copies of this ... Philadelphia, for authoring “Simple Solutions for Treating Dry Mouth.” Ask your family doctor to discontinue or provide ...

  14. Dry Mouth? Don't Delay Treatment

    MedlinePlus

    ... For Consumers Home For Consumers Consumer Updates Dry Mouth? Don't Delay Treatment Share Tweet Linkedin Pin ... saliva, cavities may occur. back to top Dry Mouth Treatments Your doctor or dentist may recommend oral ...

  15. Drying and color characteristics of coriander foliage using convective thin-layer and microwave drying.

    PubMed

    Shaw, Mark; Meda, Venkatesh; Tabil, Lope; Opoku, Anthony

    2007-01-01

    Heat sensitive properties (aromatic, medicinal, color) provide herbs and spices with their high market value. In order to prevent extreme loss of heat sensitive properties when drying herbs, they are normally dried at low temperatures for longer periods of time to preserve these sensory properties. High energy consumption often results from drying herbs over a long period. Coriander (Coriandrum sativum L., Umbelliferae) was dehydrated in two different drying units (thin layer convection and microwave dryers) in order to compare the drying and final product quality (color) characteristics. Microwave drying of the coriander foliage was faster than convective drying. The entire drying process took place in the falling rate period for both microwave and convective dried samples. The drying rate for the microwave dried samples ranged from 42.3 to 48.2% db/min and that of the convective dried samples ranged from 7.1 to 12.5% db/min. The fresh sample color had the lowest L value at 26.83 with higher L values for all dried samples. The results show that convective thin layer dried coriander samples exhibited a significantly greater color change than microwave dried coriander samples. The color change index values for the microwave dried samples ranged from 2.67 to 3.27 and that of the convective dried samples varied from 4.59 to 6.58.

  16. Compton Dry-Cask Imaging System

    ScienceCinema

    None

    2016-07-12

    The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. For more information about this project, visit http://www.inl.gov/rd100/2011/compton-dry-cask-imaging-system/

  17. Compton Dry-Cask Imaging System

    SciTech Connect

    2011-01-01

    The Compton-Dry Cask Imaging Scanner is a system that verifies and documents the presence of spent nuclear fuel rods in dry-cask storage and determines their isotopic composition without moving or opening the cask. For more information about this project, visit http://www.inl.gov/rd100/2011/compton-dry-cask-imaging-system/

  18. Composite drying with simultaneous vacuum and toggling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drying is one of key steps to govern the physical properties of leather and it is where leather acquires its final texture, consistency and flexibility. Recently we have been working diligently to improve chrome-free leather by optimizing its drying process. We developed a drying method using a co...

  19. Composite Drying with Simultaneous Vacuum and Toggling

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drying is one of key steps to govern the physical properties of leather and it is where leather acquires its final texture, consistency and flexibility. Recently we have been working diligently to improve chrome-free leather by optimizing its drying process. We developed a drying method using a co...

  20. 7 CFR 58.220 - Drying systems.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Drying systems. 58.220 Section 58.220 Agriculture....220 Drying systems. (a) Spray dryers. Spray dryers shall be of a continuous discharge type and all... Milk Products Spray Drying Systems. The filtering system shall be cleaned or component parts...

  1. 7 CFR 58.220 - Drying systems.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Drying systems. 58.220 Section 58.220 Agriculture....220 Drying systems. (a) Spray dryers. Spray dryers shall be of a continuous discharge type and all... Milk Products Spray Drying Systems. The filtering system shall be cleaned or component parts...

  2. 7 CFR 58.220 - Drying systems.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Drying systems. 58.220 Section 58.220 Agriculture....220 Drying systems. (a) Spray dryers. Spray dryers shall be of a continuous discharge type and all... Milk Products Spray Drying Systems. The filtering system shall be cleaned or component parts...

  3. Dynamic nuclear polarization-enhanced 13C NMR spectroscopy of static biological solids

    NASA Astrophysics Data System (ADS)

    Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-06-01

    We explore the possibility of using dynamic nuclear polarization (DNP) to enhance signals in structural studies of biological solids by solid state NMR without sample spinning. Specifically, we use 2D 13C-13C exchange spectroscopy to probe the peptide backbone torsion angles (ϕ, ψ) in a series of selectively 13C-labeled 40-residue β-amyloid (Aβ1-40) samples, in both fibrillar and non-fibrillar states. Experiments are carried out at 9.39 T and 8 K, using a static double-resonance NMR probe and low-power microwave irradiation at 264 GHz. In frozen solutions of Aβ1-40 fibrils doped with DOTOPA-TEMPO, we observe DNP signal enhancement factors of 16-21. We show that the orientation- and frequency-dependent spin polarization exchange between sequential backbone carbonyl 13C labels can be simulated accurately using a simple expression for the exchange rate, after experimentally determined homogeneous 13C lineshapes are incorporated in the simulations. The experimental 2D 13C-13C exchange spectra place constraints on the ϕ and ψ angles between the two carbonyl labels. Although the data are not sufficient to determine ϕ and ψ uniquely, the data do provide non-trivial constraints that could be included in structure calculations. With DNP at low temperatures, 2D 13C-13C exchange spectra can be obtained from a 3.5 mg sample of Aβ1-40 fibrils in 4 h or less, despite the broad 13C chemical shift anisotropy line shapes that are observed in static samples.

  4. Dynamic nuclear polarization-enhanced 13C NMR spectroscopy of static biological solids

    PubMed Central

    Potapov, Alexey; Yau, Wai-Ming; Tycko, Robert

    2013-01-01

    We explore the possibility of using dynamic nuclear polarization (DNP) to enhance signals in structural studies of biological solids by solid state NMR without sample spinning. Specifically, we use 2D 13C-13C exchange spectroscopy to probe the peptide backbone torsion angles (ϕ,ψ) in a series of selectively 13C-labeled 40-residue β-amyloid (Aβ1–40) samples, in both fibrillar and non-fibrillar states. Experiments are carried out at 9.39 T and 8 K, using a static double-resonance NMR probe and low-power microwave irradiation at 264 GHz. In frozen solutions of Aβ1–40 fibrils doped with DOTOPA-TEMPO, we observe DNP signal enhancement factors of 16–21. We show that the orientation- and frequency-dependent spin polarization exchange between sequential backbone carbonyl 13C labels can be simulated accurately using a simple expression for the exchange rate, after experimentally determined homogeneous 13C lineshapes are incorporated in the simulations. The experimental 2D 13C-13C exchange spectra place constraints on the ϕ and ψ angles between the two carbonyl labels. Although the data are not sufficient to determine ϕ and ψ uniquely, the data do provide non-trivial constraints that could be included in structure calculations. With DNP at low temperatures, 2D 13C-13C exchange spectra can be obtained from a 3.5 mg sample of Aβ1–40 fibrils in 4 hr or less, despite the broad 13C chemical shift anisotropy line shapes that are observed in static samples. PMID:23562665

  5. European Tamaricaceae in bioengineering on dry soils.

    PubMed

    Lavaine, Catherine; Evette, André; Piégay, Hervé

    2015-07-01

    We tested the bioengineering capabilities and resistance to drought of cuttings of two typical riparian species of Mediterranean and Alpine streams scarcely used in soil bioengineering: Myricaria germanica (L.) Desv. and Tamarix gallica L. We conducted two experiments, one ex situ and one in situ, with different drought treatments on cuttings of these two species in comparison with Salix purpurea L., a willow very commonly used in bioengineering. The biological traits considered were resprouting/survival rate, quantity of structural roots, above- and belowground biomass, shoot-to-root ratio, and ratio of the biomass increase between the first and second season. T. gallica and M. Germanica showed generally good capabilities for soil bioengineering use. T. gallica showed especially good resprouting rates in drought conditions with a survival rate of 97% in dry modality of the in situ experiment. M. germanica cuttings presented a much lower survival rate than the other two species in in situ experiments with harsh drought conditions from the beginning. T. gallica had a lower shoot-to-root ratio than S. purpurea for all drought treatments. M. germanica and T. gallica showed a very significant increase in belowground biomass during the second vegetative period, demonstrating that these species can quickly achieve strong anchoring. These observations confirmed the interest of these species in bioengineering.

  6. Biological membranes

    PubMed Central

    Watson, Helen

    2015-01-01

    Biological membranes allow life as we know it to exist. They form cells and enable separation between the inside and outside of an organism, controlling by means of their selective permeability which substances enter and leave. By allowing gradients of ions to be created across them, membranes also enable living organisms to generate energy. In addition, they control the flow of messages between cells by sending, receiving and processing information in the form of chemical and electrical signals. This essay summarizes the structure and function of membranes and the proteins within them, and describes their role in trafficking and transport, and their involvement in health and disease. Techniques for studying membranes are also discussed. PMID:26504250

  7. Synthetic biology of antimicrobial discovery.

    PubMed

    Zakeri, Bijan; Lu, Timothy K

    2013-07-19

    Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug-resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery.

  8. Synthetic biology of antimicrobial discovery

    PubMed Central

    Zakeri, Bijan; Lu, Timothy K.

    2012-01-01

    Antibiotic discovery has a storied history. From the discovery of penicillin by Sir Alexander Fleming to the relentless quest for antibiotics by Selman Waksman, the stories have become like folklore, used to inspire future generations of scientists. However, recent discovery pipelines have run dry at a time when multidrug resistant pathogens are on the rise. Nature has proven to be a valuable reservoir of antimicrobial agents, which are primarily produced by modularized biochemical pathways. Such modularization is well suited to remodeling by an interdisciplinary approach that spans science and engineering. Herein, we discuss the biological engineering of small molecules, peptides, and non-traditional antimicrobials and provide an overview of the growing applicability of synthetic biology to antimicrobials discovery. PMID:23654251

  9. Elasto-capillarity in insect fibrillar adhesion.

    PubMed

    Gernay, Sophie; Federle, Walter; Lambert, Pierre; Gilet, Tristan

    2016-08-01

    The manipulation of microscopic objects is challenging because of high adhesion forces, which render macroscopic gripping strategies unsuitable. Adhesive footpads of climbing insects could reveal principles relevant for micro-grippers, as they are able to attach and detach rapidly during locomotion. However, the underlying mechanisms are still not fully understood. In this work, we characterize the geometry and contact formation of the adhesive setae of dock beetles (Gastrophysa viridula) by interference reflection microscopy. We compare our experimental results to the model of an elastic beam loaded with capillary forces. Fitting the model to experimental data yielded not only estimates for seta adhesion and compliance in agreement with previous direct measurements, but also previously unknown parameters such as the volume of the fluid meniscus and the bending stiffness of the tip. In addition to confirming the primary role of surface tension for insect adhesion, our investigation reveals marked differences in geometry and compliance between the three main kinds of seta tips in leaf beetles. PMID:27488250

  10. Elasto-capillarity in insect fibrillar adhesion.

    PubMed

    Gernay, Sophie; Federle, Walter; Lambert, Pierre; Gilet, Tristan

    2016-08-01

    The manipulation of microscopic objects is challenging because of high adhesion forces, which render macroscopic gripping strategies unsuitable. Adhesive footpads of climbing insects could reveal principles relevant for micro-grippers, as they are able to attach and detach rapidly during locomotion. However, the underlying mechanisms are still not fully understood. In this work, we characterize the geometry and contact formation of the adhesive setae of dock beetles (Gastrophysa viridula) by interference reflection microscopy. We compare our experimental results to the model of an elastic beam loaded with capillary forces. Fitting the model to experimental data yielded not only estimates for seta adhesion and compliance in agreement with previous direct measurements, but also previously unknown parameters such as the volume of the fluid meniscus and the bending stiffness of the tip. In addition to confirming the primary role of surface tension for insect adhesion, our investigation reveals marked differences in geometry and compliance between the three main kinds of seta tips in leaf beetles.

  11. Atypical 'fibrillar' flight muscle in strepsiptera.

    PubMed

    Smith, D S; Kathirithamby, J

    1984-01-01

    The fine structure of the principal and ancillary metathoracic flight muscle fibres in the adult male of a strepsipteran, Elenchus tenuicornis, is described. Power-producing dorsal longitudinal and dorso-ventral flight muscles show features consistent with myoneural asynchrony: myofibrils are large and discrete and are separated by large closely packed mitochondria; the sarcoplasmic reticulum is very reduced but engages with T-system membranes in dyads at the mid-sarcomere H-band level. With respect to other asynchronous insect flight muscles, the fibres of Elenchus are anomalous (i) in the small fibre diameter, (ii) in the variable contour of the myofibrils and (iii) in the absence of tracheolar invagination. The functional significance of these structural features is discussed. Ancillary metathoracic muscles are structurally comparable with other synchronous fibres in possessing an extensive SR compartment. Structural evidence for asynchrony in the flight mechanism of Strepsiptera is considered in the context of the evolution of this mechanism throughout the insect Orders. PMID:6531780

  12. Tear dynamics and dry eye.

    PubMed

    Tsubota, K

    1998-10-01

    Tears undergo four processes: production by the lacrimal gland, distribution by blinking, evaporation from the ocular surface and drainage through the nasolacrimal duct. Abnormalities in any of these steps can cause dry eye. There are two kinds of tear production, basic and reflex, which can be distinguished from each other by the Schirmer test with nasal stimulation. Reflex tearing is important because it supplies such essential components as EGF and vitamin A, whose deficiency may cause squamous metaplasia. There is no reflex tearing in Sjogren's syndrome because of destruction of the lacrimal gland. In cases of diminished or absent reflex tearing, topical autologous serum is the treatment of choice. Even when there is adequate tear production, insufficient distribution, such as occurs with the decreased blinking associated with the use of video display terminals (VDT), may cause dry eye. Any process or activity that suppresses blinking interferes with tear distribution. Tear evaporation increases under certain conditions and in some diseases. When the exposed ocular surface area is increased, such as in VDT work, tear evaporation increases. Meibomian gland dysfunction (MGD) also causes increased tear evaporation by altering the quality of the oily layer in tears. Tear evaporation can be suppressed by using a warm compresser or a humidifier, narrowing the palpebral fissure, or wearing protective eyeglasses. The tear clearance rate is measured by fluorescein dye dilution in the conjunctiva. When the tear clearance is low, inflammatory cytokines or preservatives accumulate in the conjunctival sac, resulting in ocular surface diseases. Frequent use of artificial tears without preservative is the key treatment. A differential diagnosis of the abnormalities of tear dynamics can give us a proper understanding of the pathogenesis of dry eye. With this knowledge, we can formulate an efficient therapeutic approach.

  13. Dry-cleaning of graphene

    SciTech Connect

    Algara-Siller, Gerardo; Lehtinen, Ossi; Kaiser, Ute; Turchanin, Andrey

    2014-04-14

    Studies of the structural and electronic properties of graphene in its pristine state are hindered by hydrocarbon contamination on the surfaces. Also, in many applications, contamination reduces the performance of graphene. Contamination is introduced during sample preparation and is adsorbed also directly from air. Here, we report on the development of a simple dry-cleaning method for producing large atomically clean areas in free-standing graphene. The cleanness of graphene is proven using aberration-corrected high-resolution transmission electron microscopy and electron spectroscopy.

  14. Hot dry rock reservoir engineering

    SciTech Connect

    Murphy, H.

    1987-01-01

    The Hot Dry Rock (HDR) concept is a simple one. Two nearly parallel wells are drilled, and hydraulic fractures are then formed to hydraulically connect the wells. Water pumped down the injection well and through the fracture system is heated by contact with the hot rock and rises to the production well. This hot fluid is passed through a heat exchanger at the surface and the extracted heat is used for direct heating or electricity generation. The cooled production fluid is then reinjected, thereby setting up a circulation loop. This paper describes the development and execution of the HDR project at Fenton Hill, New Mexico.

  15. Experimental study of cassava sun drying

    SciTech Connect

    Njie, D.N.; Rumsey, T.R.

    1997-03-01

    Sun drying experiments were performed to compare drying of cassava chips in sheet-metal trays with drying on mesh wire trays. In the sheet-metal trays, there was air flow across the top of the bed chips, while the mesh wire trays permitted air to flow through the bed. Drying rate was faster and more uniform in the trays with through-flow air circulation. Higher temperatures were reached by chips in the sheet-metal trays than those in the mesh trays because of contact heating, but the drying rate was lower because of the reduced air flow.

  16. Dry Transfer Systems for Used Nuclear Fuel

    SciTech Connect

    Brett W. Carlsen; Michaele BradyRaap

    2012-05-01

    The potential need for a dry transfer system (DTS) to enable retrieval of used nuclear fuel (UNF) for inspection or repackaging will increase as the duration and quantity of fuel in dry storage increases. This report explores the uses for a DTS, identifies associated general functional requirements, and reviews existing and proposed systems that currently perform dry fuel transfers. The focus of this paper is on the need for a DTS to enable transfer of bare fuel assemblies. Dry transfer systems for UNF canisters are currently available and in use for transferring loaded canisters between the drying station and storage and transportation casks.

  17. Structural Biology Fact Sheet

    MedlinePlus

    ... Home > Science Education > Structural Biology Fact Sheet Structural Biology Fact Sheet Tagline (Optional) Middle/Main Content Area What is structural biology? Structural biology is a field of science focused ...

  18. Atmospheric freeze drying assisted by power ultrasound

    NASA Astrophysics Data System (ADS)

    Santacatalina, J. V.; Cárcel, J. A.; Simal, S.; Garcia-Perez, J. V.; Mulet, A.

    2012-12-01

    Atmospheric freeze drying (AFD) is considered an alternative to vacuum freeze drying to keep the quality of fresh product. AFD allows continuous drying reducing fix and operating costs, but presents, as main disadvantage, a long drying time required. The application of power ultrasound (US) can accelerate AFD process. The main objective of the present study was to evaluate the application of power ultrasound to improve atmospheric freeze drying of carrot. For that purpose, AFD experiments were carried out with carrot cubes (10 mm side) at constant air velocity (2 ms-1), temperature (-10°C) and relative humidity (10%) with (20.5 kWm-3,USAFD) and without (AFD) ultrasonic application. A diffusion model was used in order to quantify the influence of US in drying kinetics. To evaluate the quality of dry products, rehydration capacity and textural properties were determined. The US application during AFD of carrot involved the increase of drying rate. The effective moisture diffusivity identified in USAFD was 73% higher than in AFD experiments. On the other hand, the rehydration capacity was higher in USAFD than in AFD and the hardness of dried samples did not show significant (p<0.05) differences. Therefore, US application during AFD significantly (p<0.05) sped-up the drying process preserving the quality properties of the dry product.

  19. Drying of solids in fluidized beds

    SciTech Connect

    Kannan, C.S.; Thomas, P.P.; Varma, Y.B.G.

    1995-09-01

    Fluidized bed drying is advantageously adopted in industrial practice for drying of granular solids such as grains, fertilizers, chemicals, and minerals either for long shelf life or to facilitate further processing or handling. Solids are dried in batch and in continuous fluidized beds corresponding to cross-flow and countercurrent flow of phases covering a wide range in drying conditions. Materials that essentially dry with constant drying rate and then give a falling drying rate approximately linear with respect to solids moisture content (sand) as well as those with an extensive falling rate period with the subsequent falling rate being a curve with respect to the moisture content (mustard, ragi, poppy seeds) are chosen for the study. The performance of the continuous fluidized bed driers is compared with that of batch fluidized bed driers; the performance is predicted using batch kinetics, the residence time distribution of solids, and the contact efficiency between the phases.

  20. Acousto-Convective Drying of Pine Nuts

    NASA Astrophysics Data System (ADS)

    Zhilin, A. A.; Fedorov, A. V.

    2014-07-01

    An experimental investigation of the process of drying pine nut grains has been carried out by three methods: acousto-convective, thermoconvective, and thermal. A qualitative and a quantitative comparison of the dynamics of the processes of moisture extraction from the nut grains for the considered drying methods have been made. To elucidate the mechanism of moisture extraction from the pine nut grains, we carried out a separate investigation of the process of drying the nut shell and the kernel. The obtained experimental data on the acousto-convective drying of nuts are well described by the relaxation model, the data on the thermoconvective drying are well described by the bilinear law, and the data on the thermal drying are well described by the combined method consisting of three time steps characterized by different kinetic regimes of drying.

  1. Cocoon drying through solar energy

    SciTech Connect

    Kulunk, M.

    1983-12-01

    In this paper, silk cocoon drying operations through solar energy have been presented. Nearly no comprehensive work has been appeared in literature on this unusual application. General mechanism of solar drying methods are presented by some authors for instance, Roman and Jindal. This application seems vitally significant for silk cocoon producer countries like Turkey. The rate of production accelerates year by year and it is about 3000 tons per year presently in Turkey. In Turkey, by now and currently, a water vapour chamber is utilized in the killing process of silkworm. Vapour produced by burning of conventional fuels posses many drawbacks beside being very expensive and also non-renewable. Vapour effects the quality and quantity of silk thread negatively. For instance, the colour of silk cocoon tends to turn to pale instead of being gleamy. This is not tolerable. The length and mass of silk thread obtained per a typical cocoon sample is increased about 10.1 and 16.5 per cent respectively in the average by using solar energy.

  2. Dry Eye in Vernal Keratoconjunctivitis

    PubMed Central

    Villani, Edoardo; Strologo, Marika Dello; Pichi, Francesco; Luccarelli, Saverio V.; De Cillà, Stefano; Serafino, Massimiliano; Nucci, Paolo

    2015-01-01

    Abstract The purpose of this comparative cross-sectional study was to investigate the use of standardized clinical tests for dry eye in pediatric patients with active and quiet vernal keratoconjunctivitis (VKC) and to compare them with healthy children. We recruited 35 active VKC, 35 inactive VKC, and 70 age-matched control healthy subjects. Each child underwent a complete eye examination, including visual analog scale symptoms assessment, biomicroscopy, fluorescein break-up time (BUT), corneal fluorescein and conjunctival lissamine green staining, corneal esthesiometry, Schirmer test with anesthetic, and meibomian glands inspection and expression. Active VKC patients showed significantly increased symptoms and signs of ocular surface disease, compared with the other 2 groups. Inactive VKC patients, compared with control subjects, showed increased photophobia (P < 0.05; Mann-Whitney U test), conjunctival lissamine green staining and Schirmer test values, and reduced BUT and corneal sensitivity [P < 0.05 by analysis of variance (ANOVA) least significant difference posthoc test for BUT and Schirmer; P < 0.001 by Mann-Whitney U test for lissamine green staining and corneal sensitivity]. Our results confirm the association between VKC and short-BUT dry eye. This syndrome seems to affect the ocular surface in quiescent phases too, determining abnormalities in tear film stability, epithelial cells integrity, and corneal nerves function. The very long-term consequences of this perennial mechanism of ocular surface damage have not been fully understood yet. PMID:26496269

  3. Characterization of dry biopotential electrodes.

    PubMed

    Xie, Li; Yang, Geng; Xu, Linlin; Seoane, Fernando; Chen, Qiang; Zheng, Lirong

    2013-01-01

    Driven by the increased interest in wearable long-term healthcare monitoring systems, varieties of dry electrodes are proposed based on different materials with different patterns and structures. Most of the studies reported in the literature focus on proposing new electrodes and comparing its performance with commercial electrodes. Few papers are about detailed comparison among different dry electrodes. In this paper, printed metal-plate electrodes, textile based electrodes, and spiked electrodes are for the first time evaluated and compared under the same experimental setup. The contact impedance and noise characterization are measured. The in-vivo electrocardiogram (ECG) measurement is applied to evaluate the overall performance of different electrodes. Textile electrodes and printed electrodes gain comparable high-quality ECG signals. The ECG signal obtained by spiked electrodes is noisier. However, a clear ECG envelope can be observed and the signal quality can be easily improved by backend signal processing. The features of each type of electrodes are analyzed and the suitable application scenario is addressed.

  4. Arsenic Sorption in Dried Leaves

    NASA Astrophysics Data System (ADS)

    Silva, Gabriela C.; de Carvalho, Regina P.; Duarte, Grazielle; Santos, Mércia H.

    2005-10-01

    Biosorption is the retention of metal ions from aqueous solutions by biomasses. This phenomenon can be helpful in the design of alternative filters for the depollution of industrial and mining waste waters. The recovery of filtered metal ions can also be commercially interesting. Although many studies about the sorptive capacity of biomasses have been done for different metals, few have investigated sorption sites and mechanisms in these systems. We studied the retention of arsenic ions from aqueous solutions using dried lettuce leaves (L. sativa) as biomass. The toxic arsenic forms As(III) and As(V) are commonly found in mining waste waters. Early studies have shown that lettuce leaves have a good sorptive capacity for copper and iron ions, comparable to other sorbents such as activated carbon or ionic-exchange resins. Arsenic sorption by lettuce dried leaves was not found to be effective when in natura biomass was used. Sorptive capacity was improved and became comparable to the sorption of the other ions studied when the biomass was charged with Fe(III). The sorption mechanism of arsenic in Fe-charged biomass must be similar to the one proposed for As sorption by mineral clays, where As ions bind to Fe(III) atoms in the clay structure.

  5. Dry borax applicator operator's manual.

    SciTech Connect

    Karsky, Richard, J.

    1999-01-01

    Annosum root rot affects conifers throughout the Northern Hemisphere, infecting their roots and eventually killing the trees. The fungus Heterobasidion annosum causes annosum root rot. The fungus colonizes readily on freshly cut stumps. Partially cut stands have a high risk of infestation because the fungus can colonize on each of the stumps and potentially infect the neighboring trees. Wind and rain carry the annosum spores. Spores that land on freshly cut stumps grow down the stump's root system where they can infect living trees through root grafts or root contacts. Once annosum becomes established, it can remain active for many years in the Southern United States and for several decades in the north. About 7% of the trees that become infected die. When thinning, stumps can be treated successfully using a competing fungus, Phlebia gigantea, and with ''Tim-Bor'' in liquid formulations. These liquid products are no longer approved in the United States. Only the dry powder form is registered and approved by the EPA. Stumps can be treated with a dry formula of borax, (Sporax), significantly reducing one of the primary routes by which Heterobasidion annosum infects a stand of trees. Sporax is used by the USDA Forest Service to control annosum root rot. Sporax is now applied by hand, but once the felled trees are skidded it becomes very hard to locate the stumps. A stump applicator will reduce error, labor costs, and hazards to workers.

  6. Biology Cognitive Preferences of Preservice Biology Teachers.

    ERIC Educational Resources Information Center

    Cheng, Yeong-Jing

    1991-01-01

    The Biology Cognitive Preference Inventory (BCPI) for investigating the biology cognitive preference styles of 143 students in the biology teacher education program was developed and validated. The cognitive preferences include factual information or recall, principles, questioning, and applications. Preservice biology teachers exhibited a strong…

  7. Simulating Biological and Non-Biological Motion

    ERIC Educational Resources Information Center

    Bruzzo, Angela; Gesierich, Benno; Wohlschlager, Andreas

    2008-01-01

    It is widely accepted that the brain processes biological and non-biological movements in distinct neural circuits. Biological motion, in contrast to non-biological motion, refers to active movements of living beings. Aim of our experiment was to investigate the mechanisms underlying mental simulation of these two movement types. Subjects had to…

  8. Biological Literacy in a College Biology Classroom.

    ERIC Educational Resources Information Center

    Demastes, Sherry; Wandersee, James H.

    1992-01-01

    Examines the proposed definition of biological literacy as the understanding of a small number of pervasive biological principles appropriate to making informed personal and societal decisions. Utilizes the content of a major daily newspaper to adjust biology instruction to focus on this notion of biological literacy. Discusses benefits and…

  9. Ohmic pre-drying of tomato paste.

    PubMed

    Hosainpour, Adel; Darvishi, Hosain; Nargesi, Farzad; Fadavi, Ali

    2014-04-01

    In this study, the effects of ohmic pre-drying technique on moisture ratio, drying rate, drying time, specific energy consumption, drying efficiency, and effective moisture diffusivity of tomato paste were investigated. Pre-drying experiments were carried out in an ohmic laboratory dryer at voltage gradient levels of 6, 8, 10, 12, 14, and 16 V/cm and oven at 105  and 1.0 m/s air velocity (control sample). Pre-drying was accomplished till the moisture content of the tomato paste reduced from initial moisture content of 90% (w.b.) to a safer level of 70% (w.b.). The ohmic pre-drying reduced the drying time of tomato paste by 80-97%, compared with the hot air drying. Pre-drying took place mainly in warming up, constant rate, and falling rate periods. Six available moisture-ratio models were fitted to the pre-drying data. The results showed that the Midilli et al. model is the most appropriate model for pre-drying behavior of tomato paste. The effective moisture diffusivity varied from 5.39 × 10(-8) to 3.91 × 10(-7)m(2)/s with an activation energy of 2.082 (V/g.cm). Both specific energy consumption and drying efficiency were considerably enhanced by increasing voltage gradient. It was found that the specific energy consumption and drying efficiency varied from 3.72 to 2.29 MJ/kg water and 67.8 to 83.8%, respectively. PMID:23744116

  10. Ohmic pre-drying of tomato paste.

    PubMed

    Hosainpour, Adel; Darvishi, Hosain; Nargesi, Farzad; Fadavi, Ali

    2014-04-01

    In this study, the effects of ohmic pre-drying technique on moisture ratio, drying rate, drying time, specific energy consumption, drying efficiency, and effective moisture diffusivity of tomato paste were investigated. Pre-drying experiments were carried out in an ohmic laboratory dryer at voltage gradient levels of 6, 8, 10, 12, 14, and 16 V/cm and oven at 105  and 1.0 m/s air velocity (control sample). Pre-drying was accomplished till the moisture content of the tomato paste reduced from initial moisture content of 90% (w.b.) to a safer level of 70% (w.b.). The ohmic pre-drying reduced the drying time of tomato paste by 80-97%, compared with the hot air drying. Pre-drying took place mainly in warming up, constant rate, and falling rate periods. Six available moisture-ratio models were fitted to the pre-drying data. The results showed that the Midilli et al. model is the most appropriate model for pre-drying behavior of tomato paste. The effective moisture diffusivity varied from 5.39 × 10(-8) to 3.91 × 10(-7)m(2)/s with an activation energy of 2.082 (V/g.cm). Both specific energy consumption and drying efficiency were considerably enhanced by increasing voltage gradient. It was found that the specific energy consumption and drying efficiency varied from 3.72 to 2.29 MJ/kg water and 67.8 to 83.8%, respectively.

  11. Dry-cured ham restructured with fibrin.

    PubMed

    Romero de Ávila, M D; Hoz, L; Ordóñez, J A; Cambero, M I

    2014-09-15

    The viability of a fibrinogen-thrombin system (FT) to bind fresh deboned hams for incorporation in the salting and ripening processes, to produce cured ham, was studied. The effects of the different processing variables (pH, NaCl concentration, temperature and gelation time) on FT, a meat emulsion mixed with FT, fresh pork portions and deboned hams restructured with FT were analyzed. The most stable and firmest fibrin gels were obtained after 6h of adding the FT, with less than 2% NaCl and pH 7-8.4. Scanning electron microscopy of the fibrin gel showed fibrillar structures with a high degree of cross-linking and a high density. Two structures were found in the binding area of restructured meat; one in the central part with similar characteristics to fibrin gels and, another in the area of contact between the meat surfaces, where a filamentous structure connected the fibrin gels with the muscle bundles. PMID:24767091

  12. CO2 (dry ice) cleaning system

    NASA Technical Reports Server (NTRS)

    Barnett, Donald M.

    1995-01-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  13. CO2 (dry ice) cleaning system

    NASA Astrophysics Data System (ADS)

    Barnett, Donald M.

    1995-03-01

    Tomco Equipment Company has participated in the dry ice (solid carbon dioxide, CO2) cleaning industry for over ten years as a pioneer in the manufacturer of high density, dry ice cleaning pellet production equipment. For over four years Tomco high density pelletizers have been available to the dry ice cleaning industry. Approximately one year ago Tomco introduced the DI-250, a new dry ice blast unit making Tomco a single source supplier for sublimable media, particle blast, cleaning systems. This new blast unit is an all pneumatic, single discharge hose device. It meters the insertion of 1/8 inch diameter (or smaller), high density, dry ice pellets into a high pressure, propellant gas stream. The dry ice and propellant streams are controlled and mixed from the blast cabinet. From there the mixture is transported to the nozzle where the pellets are accelerated to an appropriate blasting velocity. When directed to impact upon a target area, these dry ice pellets have sufficient energy to effectively remove most surface coatings through dry, abrasive contact. The meta-stable, dry ice pellets used for CO2 cleaning, while labeled 'high density,' are less dense than alternate, abrasive, particle blast media. In addition, after contacting the target surface, they return to their equilibrium condition: a superheated gas state. Most currently used grit blasting media are silicon dioxide based, which possess a sharp tetrahedral molecular structure. Silicon dioxide crystal structures will always produce smaller sharp-edged replicas of the original crystal upon fracture. Larger, softer dry ice pellets do not share the same sharp-edged crystalline structures as their non-sublimable counterparts when broken. In fact, upon contact with the target surface, dry ice pellets will plastically deform and break apart. As such, dry ice cleaning is less harmful to sensitive substrates, workers and the environment than chemical or abrasive cleaning systems. Dry ice cleaning system

  14. Dry fermentation of agricultural residues

    NASA Astrophysics Data System (ADS)

    Jewell, W. J.; Chandler, J. A.; Dellorto, S.; Fanfoni, K. J.; Fast, S.; Jackson, D.; Kabrick, R. M.

    1981-09-01

    A dry fermentation process is discussed which converts agricultural residues to methane, using the residues in their as produced state. The process appears to simplify and enhance the possibilities for using crop residues as an energy source. The major process variables investigated include temperature, the amount and type of inoculum, buffer requirements, compaction, and pretreatment to control the initial available organic components that create pH problems. A pilot-scale reactor operation on corn stover at a temperature of 550 C, with 25 percent initial total solids, a seed-to-feed ratio of 2.5 percent, and a buffer-to-feed ratio of 8 percent achieved 33 percent total volatile solids destruction in 60 days. Volumetric biogas yields from this unit were greater than 1 vol/vol day for 12 days, and greater than 0.5 vol/vol day for 32 days, at a substrate density of 169 kg/m (3).

  15. Wetter for fine dry powder

    DOEpatents

    Hall, James E.; Williams, Everett H.

    1977-01-01

    A system for wetting fine dry powders such as bentonite clay with water or other liquids is described. The system includes a wetting tank for receiving water and a continuous flow of fine powder feed. The wetting tank has a generally square horizontal cross section with a bottom end closure in the shape of an inverted pyramid. Positioned centrally within the wetting tank is a flow control cylinder which is supported from the walls of the wetting tank by means of radially extending inclined baffles. A variable speed motor drives a first larger propeller positioned immediately below the flow control cylinder in a direction which forces liquid filling the tank to flow downward through the flow control cylinder and a second smaller propeller positioned below the larger propeller having a reverse pitch to oppose the flow of liquid being driven downward by the larger propeller.

  16. Setting up the drying regimes based on the theory of moisture migration during drying

    NASA Astrophysics Data System (ADS)

    Vasić, M.; Radojević, Z.

    2016-08-01

    Drying is energy intensive process which has important effect on the quality of the clay tiles that are dried commercially. Chamber and tunnel dryers are constantly improving. Better technical equipment and operational strategies have lead to higher quality of the dried clay products. The moisture migration during isothermal drying process can be visually traced on the curve that represents the relationship between variable effective moisture diffusivity (MR) with time (t). Proposed non isothermal drying regimes were consisted from several isothermal segments. For the first time, the choice of isothermal segments specification and its duration was not specified by experience or by trial-and-error method. It was detected from the isothermal curves Deff - MR in accordance with the theory of moisture migration during drying. Proposed drying regimes were tested. Clay roofing tiles were dried without cracks. Dried clay roofing tiles has satisfied all requirements defined in EN 1304 norm related to the shape regularity and mechanical properties.

  17. Drying characteristics of ultrasound assisted hot air drying of Flos Lonicerae.

    PubMed

    Liu, Yunhong; Sun, Yue; Miao, Shuai; Li, Fang; Luo, Denglin

    2015-08-01

    Ultrasound assisted hot air drying of Flos Lonicerae was investigated in this study. The effects of drying parameters such as ultrasonic radiation distance, ultrasonic power and drying temperature on drying characteristics were discussed. The results showed that ultrasound application has positive and significant effects on hot air drying. Shortening ultrasonic radiation distance is beneficial to improve both ultrasonic energy efficiency and drying rate. Higher ultrasonic power had more positive and significant effects on drying rate. The influence of ultrasound power on drying rate decreased along with the decrease of moisture content during drying process, especially at low ultrasound powers. The increase of drying temperature significantly caused the reduction of drying time. D eff values ranged from 5.05 × 10(-11) to 20.33 × 10(-11) m(2)/s in ultrasound assisted hot air drying of Flos Lonicerae, and increased with the increase in drying temperature and ultrasonic power. The corresponding activation energy values ranged from 28.90 to 36.05 kJ/mol, and decreased with the increase in applied ultrasonic power. Therefore, ultrasound assistance is a helpful and promising method to enhance hot air drying process.

  18. Measurement of Single Cell Refractive Index, Dry Mass, Volume, and Density Using a Transillumination Microscope

    NASA Astrophysics Data System (ADS)

    Phillips, Kevin G.; Jacques, Steven L.; McCarty, Owen J. T.

    2012-09-01

    Phase contrast microscopy has become ubiquitous in the field of biology, particularly in qualitative investigations of cellular morphology. However, the use of quantitative phase retrieval methods and their connection to cellular refractive index and dry mass density remain under utilized. This is due in part to the restriction of phase and cellular mass determination to custom built instruments, involved mathematical analysis, and prohibitive sample perturbations. We introduce tomographic bright field imaging, an accessible optical imaging technique enabling the three dimensional measurement of cellular refractive index and dry mass density using a standard transillumination optical microscope. The validity of the technique is demonstrated on polystyrene spheres. The technique is then applied to the measurement of the refractive index, dry mass, volume, and density of red blood cells. This optical technique enables a simple and robust means to perform quantitative investigations of engineered and biological specimens in three dimensions using standard optical microscopes.

  19. Evaluation of biogas production by dry anaerobic digestion of switchgrass-animal manure mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application without adverse environmental effects. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion (> 15% TS; total solid) has an advantage ov...

  20. Dry needling — peripheral and central considerations

    PubMed Central

    Dommerholt, Jan

    2011-01-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture. PMID:23115475

  1. Drying apparatus for photographic sheet material

    NASA Technical Reports Server (NTRS)

    Epstein, P.; Donovan, G.; Lawhite, E. (Inventor)

    1973-01-01

    An elongated drying chamber is provided with transport means for carrying photographic sheet material edgewise with the sheets in end-to-end relationship past a plurality of tubes that issue drying air streams. The tubes are slotted a distance equal to substantially the full width of the sheet material for complete, gentle drying by sheets of air. A common plenum supplies the tubes with heated air; the air is directed from the tube slots at a pronounced angle to the sheet surface to provide for arraying the tubes close to the surface for maximum drying effect while minimizing the danger of mechanical interference between the edges of the sheets and the slots in the tubes. The driver for the transport is housed in an enclosure between the plenum and the drying chamber; an air return duct is provided along another side to complete insulation of the drying chamber from ambient conditions.

  2. Dry needling - peripheral and central considerations.

    PubMed

    Dommerholt, Jan

    2011-11-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture.

  3. Cell biology perspectives in phage biology.

    PubMed

    Ansaldi, Mireille

    2012-01-01

    Cellular biology has long been restricted to large cellular organisms. However, as the resolution of microscopic methods increased, it became possible to study smaller cells, in particular bacterial cells. Bacteriophage biology is one aspect of bacterial cell biology that has recently gained insight from cell biology. Despite their small size, bacteriophages could be successfully labeled and their cycle studied in the host cells. This review aims to put together, although non-extensively, several cell biology studies that recently pushed the elucidation of key mechanisms in phage biology, such as the lysis-lysogeny decision in temperate phages or genome replication and transcription, one step further.

  4. Wet/dry cooling tower and method

    DOEpatents

    Glicksman, Leon R.; Rohsenow, Warren R.

    1981-01-01

    A wet/dry cooling tower wherein a liquid to-be-cooled is flowed along channels of a corrugated open surface or the like, which surface is swept by cooling air. The amount of the surface covered by the liquid is kept small compared to the dry part thereof so that said dry part acts as a fin for the wet part for heat dissipation.

  5. Sperm preservation by freeze-drying for the conservation of wild animals.

    PubMed

    Kaneko, Takehito; Ito, Hideyuki; Sakamoto, Hidefusa; Onuma, Manabu; Inoue-Murayama, Miho

    2014-01-01

    Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. A new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4 °C. Sperm are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. We demonstrate that chimpanzee, giraffe, jaguar, weasel and the long-haired rat sperm remain viable after freeze-drying. In all species, pronuclei were formed after the injection of freeze-dried sperm into the mouse oocytes. Although preliminary, these results may be useful for the future establishment of "freeze-drying zoo" to conserve wild animals.

  6. Sperm preservation by freeze-drying for the conservation of wild animals.

    PubMed

    Kaneko, Takehito; Ito, Hideyuki; Sakamoto, Hidefusa; Onuma, Manabu; Inoue-Murayama, Miho

    2014-01-01

    Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. A new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4 °C. Sperm are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. We demonstrate that chimpanzee, giraffe, jaguar, weasel and the long-haired rat sperm remain viable after freeze-drying. In all species, pronuclei were formed after the injection of freeze-dried sperm into the mouse oocytes. Although preliminary, these results may be useful for the future establishment of "freeze-drying zoo" to conserve wild animals. PMID:25409172

  7. Sperm Preservation by Freeze-Drying for the Conservation of Wild Animals

    PubMed Central

    Kaneko, Takehito; Ito, Hideyuki; Sakamoto, Hidefusa; Onuma, Manabu; Inoue-Murayama, Miho

    2014-01-01

    Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. A new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4°C. Sperm are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. We demonstrate that chimpanzee, giraffe, jaguar, weasel and the long-haired rat sperm remain viable after freeze-drying. In all species, pronuclei were formed after the injection of freeze-dried sperm into the mouse oocytes. Although preliminary, these results may be useful for the future establishment of “freeze-drying zoo” to conserve wild animals. PMID:25409172

  8. Preparation of nanoscale pulmonary drug delivery formulations by spray drying.

    PubMed

    Bohr, Adam; Ruge, Christian A; Beck-Broichsitter, Moritz

    2014-01-01

    Advances in preparation technologies for nanomedicines have provided novel formulations for pulmonary drug delivery. Application of drugs via the lungs can be considered as one of the most attractive implementations of nanoparticles for therapeutic use due to the unique anatomy and physiology of the lungs. The colloidal nature of nanoparticles provides important advantages to the formulation of drugs, which are normally difficult to administer due to poor stability or uptake, partly because nanoparticles protect the drug from the physiological milieu, facilitate transport across biological barriers and can offer controlled drug release. There are numerous methods for producing therapeutic nanoparticles, each with their own advantages and suitable application. Liquid atomization techniques such as spray drying can produce nanoparticle formulations in a dry powder form suitable for pulmonary administration in a direct one-step process. This chapter describes the different state-of-the-art techniques used to prepare drug nanoparticles (with special emphasize on spray drying techniques) and the strategies for administering such unique formulations to the pulmonary environment.

  9. Physical Properties of Cell Water in Partially Dried Saccharomyces cerevisiae

    PubMed Central

    Koga, Shozo; Echigo, Akira; Nunomura, Kazuko

    1966-01-01

    The equilibrium vapor pressure, the heat of vaporization, the dielectric increment, and the NMR spectra of partially dried cells were studied in Saccharomyces cerevisiae with water contents varying in the range from 25 to 0.8%. The comparative study of those physical properties suggests that physical states of the microbe can be classified into four regions in accordance with the states of the cell water: the solution region, the gel region, the mobile adsorption region, and the localized water region. Much difference in the physiological properties is found between the cells in the solution region and those in the gel region, whereas the pattern changes in physical properties take place when the cells in the gel region are dried to a further extent into the mobile or the localized region. The various modes in the molecular motion of the cell water reflected in those physical properties of the cell seem to give some insight into the biological functions of the molecule in the native as well as the dried states of the cell. PMID:5970569

  10. FINAL REPORT: Transformational electrode drying process

    SciTech Connect

    Claus Daniel, C.; Wixom, M.

    2013-12-19

    This report includes major findings and outlook from the transformational electrode drying project performance period from January 6, 2012 to August 1, 2012. Electrode drying before cell assembly is an operational bottleneck in battery manufacturing due to long drying times and batch processing. Water taken up during shipment and other manufacturing steps needs to be removed before final battery assembly. Conventional vacuum ovens are limited in drying speed due to a temperature threshold needed to avoid damaging polymer components in the composite electrode. Roll to roll operation and alternative treatments can increase the water desorption and removal rate without overheating and damaging other components in the composite electrode, thus considerably reducing drying time and energy use. The objective of this project was the development of an electrode drying procedure, and the demonstration of processes with no decrease in battery performance. The benchmark for all drying data was an 80°C vacuum furnace treatment with a residence time of 18 – 22 hours. This report demonstrates an alternative roll to roll drying process with a 500-fold improvement in drying time down to 2 minutes and consumption of only 30% of the energy compared to vacuum furnace treatment.

  11. Optimal energy management in grain drying.

    PubMed

    Gunasekaran, S

    1986-01-01

    Grain drying is very specific to the geographic location, kind of drying system, and the type of grain. Under a given set of conditions, the optimal system can be selected based on careful evaluation. However, a good choice of drying systems, procedures, and management practices can be made from the information already available. The review of several grain-drying procedures has provided some insight in making a quick evaluation of the process and arriving at the most suitable system for a particular application. Despite extensive research efforts, the present knowledge of grain drying is yet insufficient to optimally design each drying process with respect to capacity, quality, and energy requirement. There is a need for incorporating grain and air parameters more accurately. It is also important to develop comprehensive drying simulation models to encompass agronomic practices, such as planting and harvesting. Recent efforts indicate a strong influence of planting and harvesting strategies on optimal drying and storage system selection. Results of the varietal trials at Ohio State University indicate that it is now possible to select midseason varieties, which dry down rapidly, without sacrificing yield. Also, low moisture at harvest is important to the energy management process because it affects total drying time and energy required. It is also important from a quality standpoint because kernel damage increases rapidly at harvesting moisture levels above 25%. The trend in grain-dryer design has shifted from focusing on drying capacity and operation reliability to energy consumption. The development in design of energy efficient continuous-flow dryers has been significant. Multistage concurrentflow dryers are excellent examples. Various aspects of dryer staging for efficient operation and control are yet to be determined. Recirculation of the exhaust air is a proven method of improving energy efficiency. Likewise, in batch-in-bin systems, stirring and

  12. Cold vacuum drying facility design requirements

    SciTech Connect

    IRWIN, J.J.

    1999-07-01

    This document provides the detailed design requirements for the Spent Nuclear Fuel Project Cold Vacuum Drying Facility. Process, safety, and quality assurance requirements and interfaces are specified.

  13. Liquid Crystal Research Shows Deformation By Drying

    NASA Technical Reports Server (NTRS)

    2003-01-01

    These images, from David Weitz's liquid crystal research, show ordered uniform sized droplets (upper left) before they are dried from their solution. After the droplets are dried (upper right), they are viewed with crossed polarizers that show the deformation caused by drying, a process that orients the bipolar structure of the liquid crystal within the droplets. When an electric field is applied to the dried droplets (lower left), and then increased (lower right), the liquid crystal within the droplets switches its alignment, thereby reducing the amount of light that can be scattered by the droplets when a beam is shone through them.

  14. Optimal energy management in grain drying.

    PubMed

    Gunasekaran, S

    1986-01-01

    Grain drying is very specific to the geographic location, kind of drying system, and the type of grain. Under a given set of conditions, the optimal system can be selected based on careful evaluation. However, a good choice of drying systems, procedures, and management practices can be made from the information already available. The review of several grain-drying procedures has provided some insight in making a quick evaluation of the process and arriving at the most suitable system for a particular application. Despite extensive research efforts, the present knowledge of grain drying is yet insufficient to optimally design each drying process with respect to capacity, quality, and energy requirement. There is a need for incorporating grain and air parameters more accurately. It is also important to develop comprehensive drying simulation models to encompass agronomic practices, such as planting and harvesting. Recent efforts indicate a strong influence of planting and harvesting strategies on optimal drying and storage system selection. Results of the varietal trials at Ohio State University indicate that it is now possible to select midseason varieties, which dry down rapidly, without sacrificing yield. Also, low moisture at harvest is important to the energy management process because it affects total drying time and energy required. It is also important from a quality standpoint because kernel damage increases rapidly at harvesting moisture levels above 25%. The trend in grain-dryer design has shifted from focusing on drying capacity and operation reliability to energy consumption. The development in design of energy efficient continuous-flow dryers has been significant. Multistage concurrentflow dryers are excellent examples. Various aspects of dryer staging for efficient operation and control are yet to be determined. Recirculation of the exhaust air is a proven method of improving energy efficiency. Likewise, in batch-in-bin systems, stirring and

  15. Paleolimnology of the McMurdo Dry Valleys, Antarctica.

    PubMed

    Doran, P T; Wharton, R A; Lyons, W B

    1994-01-01

    The McMurdo Dry Valleys presently contain more than 20 permanent lakes and ponds, which vary markedly in character. All, with the exception of a hypersaline pond, have a perennial ice-cover. The dry valley lakes, and lakes in other ice-free regions of continental Antarctica, are unique on this planet in that they consistently maintain a thick year-round ice cover (2.8-6.0 m) over liquid water. The persistent ice covers minimize wind-generated currents and reduce light penetration, as well as restricting sediment deposition into a lake and the exchange of atmospheric gases between the water column and the atmosphere. From a paleolimnological perspective, the dry valley lakes offer an important record of catchment and environmental changes. These lakes are also modern-day equivalents of periglacial lakes that were common during glacial periods at temperate latitudes. The present lakes are mostly remnants of larger glacial lakes that occupied the valleys in the past, perhaps up to 4.6 Ma ago. Two of the valleys contain evidence of being filled with large glacial lakes within the last 10000 years. Repeated drying and filling events since then have left a characteristic impression on the salt profiles of some lakes creating a unique paleo-indicator within the water column. These events are also marked in the sediments by the concentration and dilution of certain chemical constituents, particularly salts, and are also corroborated by carbonate speciation and oxygen isotope analysis. Stratigraphic analysis of dry valley lake sediments is made difficult by the occurrence of an 'old carbon' reservoir creating spurious radiocarbon dates, and by the high degree of spatial variability in lake sedimentation. From a biological perspective, the lakes are relatively simple, containing various taxa of planktonic and benthic microorganisms, but no higher forms of life, which is an advantage to paleolimnologists because there is no bioturbation in the sediments. Useful biological

  16. Paleolimnology of the McMurdo Dry Valleys, Antarctica

    NASA Technical Reports Server (NTRS)

    Doran, P. T.; Wharton, R. A. Jr; Lyons, W. B.; Wharton RA, J. r. (Principal Investigator)

    1994-01-01

    The McMurdo Dry Valleys presently contain more than 20 permanent lakes and ponds, which vary markedly in character. All, with the exception of a hypersaline pond, have a perennial ice-cover. The dry valley lakes, and lakes in other ice-free regions of continental Antarctica, are unique on this planet in that they consistently maintain a thick year-round ice cover (2.8-6.0 m) over liquid water. The persistent ice covers minimize wind-generated currents and reduce light penetration, as well as restricting sediment deposition into a lake and the exchange of atmospheric gases between the water column and the atmosphere. From a paleolimnological perspective, the dry valley lakes offer an important record of catchment and environmental changes. These lakes are also modern-day equivalents of periglacial lakes that were common during glacial periods at temperate latitudes. The present lakes are mostly remnants of larger glacial lakes that occupied the valleys in the past, perhaps up to 4.6 Ma ago. Two of the valleys contain evidence of being filled with large glacial lakes within the last 10000 years. Repeated drying and filling events since then have left a characteristic impression on the salt profiles of some lakes creating a unique paleo-indicator within the water column. These events are also marked in the sediments by the concentration and dilution of certain chemical constituents, particularly salts, and are also corroborated by carbonate speciation and oxygen isotope analysis. Stratigraphic analysis of dry valley lake sediments is made difficult by the occurrence of an 'old carbon' reservoir creating spurious radiocarbon dates, and by the high degree of spatial variability in lake sedimentation. From a biological perspective, the lakes are relatively simple, containing various taxa of planktonic and benthic microorganisms, but no higher forms of life, which is an advantage to paleolimnologists because there is no bioturbation in the sediments. Useful biological

  17. Stabilisation of proteins via mixtures of amino acids during spray drying.

    PubMed

    Ajmera, Ankur; Scherließ, Regina

    2014-03-10

    Biologicals are often formulated as solids in an effort to preserve stability which generally requires stabilising excipients for proper drying. The purpose of this study was to screen amino acids and their combinations for their stabilising effect on proteins during spray drying. Catalase, as model protein, was spray dried in 1+1 or 1+2 ratios with amino acids. Some amino acids namely arginine, glycine and histidine showed good retention of catalase functionality after spray drying and subsequent storage stress. A 1+1 combination of arginine and glycine in a 1+2 ratio with catalase resulted in a tremendously good stabilising effect. Storage at high temperature/humidity also showed beneficial effects of this combination. To evaluate whether this was a general principle, these findings were transferred to an antigenic protein of comparable size and supramolecular structure (haemagglutinin) as well as to a smaller enzyme (lysozyme). Upon spray drying with the combination of amino acids it could be shown that both proteins remain more stable especially after storage compared to the unprotected protein. The combination of arginine and glycine is tailored to the needs of protein stabilisation during spray drying and may hence be utilised in dry powder formulation of biomolecules with superior stability characteristics. PMID:24412336

  18. Experimental Performance of a Thermoelectric Heat-Pump Drying System for Drying Herbs

    NASA Astrophysics Data System (ADS)

    Wongsim, K.; Jamradloedluk, J.; Lertsatitthanakorn, C.; Siriamornpun, S.; Rungsiyopas, M.; Soponronnarit, S.

    2015-06-01

    In this study we investigated thermoelectric (TE) heat-pump drying of laurel clock vine leaves, and the effect of drying-air temperature on the characteristics of the leaves. The TE drying system comprised four TE modules each with its own rectangular fin heat sink. The hot side of each TE module was fixed to its own heat sink; the cold sides were fixed to heat-pipe heat sinks and a drying chamber. The drying time depended on drying-air temperature. The heating capacity and coefficient of performance (COP) increased as the current supplied to the TE modules was increased. Calculated COP for the entire TE heat-pump drying system were 1.28 and 0.81 for drying-air temperatures of 50 and 40°C, respectively.

  19. Evaluation of the desiccation tolerance of blastospores of Paecilomyces fumosoroseus (Deuteromycotina: Hyphomyces)using a lab- scale, air-drying chamber with controlled relative humidity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The stabilization of living microbial agents for use as biological control agents is often accomplished through desiccation. The drying process must be conducive to the survival of the living microbial agent during desiccation and storage. Our air-drying studies with liquid culture-produced blasto...

  20. 7 CFR 58.153 - Dry storage.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Dry storage. 58.153 Section 58.153 Agriculture... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.153 Dry storage. The product should be stored at least 18 inches from the wall in aisles, rows,...

  1. 7 CFR 58.153 - Dry storage.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Dry storage. 58.153 Section 58.153 Agriculture... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.153 Dry storage. The product should be stored at least 18 inches from the wall in aisles, rows,...

  2. 7 CFR 58.153 - Dry storage.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Dry storage. 58.153 Section 58.153 Agriculture... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.153 Dry storage. The product should be stored at least 18 inches from the wall in aisles, rows,...

  3. 7 CFR 58.153 - Dry storage.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Dry storage. 58.153 Section 58.153 Agriculture... Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Storage of Finished Product § 58.153 Dry storage. The product should be stored at least 18 inches from the wall in aisles, rows,...

  4. WET AND DRY SCRUBBERS FOR EMISSION CONTROL

    EPA Science Inventory

    Generally speaking, absorption equipment includes two major categories: Wet adsorption scrubbers (or wet scrubbers); Dry absorption scrubbers (or dry scrubbers).
    Wet scrubbers: As the name implies, wet scrubbers (also known as wet collectors) are devices which use a liquid fo...

  5. 7 CFR 58.813 - Dry whey.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., GENERAL SPECIFICATIONS FOR APPROVED PLANTS AND STANDARDS FOR GRADES OF DAIRY PRODUCTS 1 General Specifications for Dairy Plants Approved for USDA Inspection and Grading Service 1 Requirements for Finished Products Bearing Usda Official Identification § 58.813 Dry whey. The quality requirements for dry...

  6. Hot-dry-rock feasibility study

    SciTech Connect

    Not Available

    1981-08-01

    The hot-dry-rock project tasks are covered as follows: hot-dry-rock reservoir; generation facilities; water resources; transmission requirements; environmental issues; government and community institutional factors; leasing, ownership and management of facilities; regulations, permits, and laws; and financial considerations. (MHR)

  7. EMISSIONS OF PERCHLOROETHYLENE FROM DRY CLEANED FABRICS

    EPA Science Inventory

    A study was conducted to evaluate the emissions of perchloroethylene (tetrachloroethylene) from dry cleaned fabrics to determine: (a) how the introduction of fresh dry cleaning into a home affects the indoor concentration of perchloroethylene, and (b) the effectiveness of ‘airing...

  8. Reflectance characteristics of dry plant materials

    NASA Technical Reports Server (NTRS)

    Elvidge, Christopher D.

    1987-01-01

    Chlorophyll and water obscure the absorption features of all other leaf constituents in the spectra of green leaves. The predominant near-IR and thermal IR spectral features of dry plant materials originate from lignin, cellulose, and hemicellulose. These compounds account for 80 to 98 percent of the dry weight in most plant materials.

  9. Emissions of perchloroethylene from dry cleaned fabrics

    NASA Astrophysics Data System (ADS)

    Tichenor, Bruce A.; Sparks, Leslie E.; Jackson, Merrill D.; Guo, Zhishi; Mason, Mark A.; Michelle Plunket, C.; Rasor, Susan A.

    A study was conducted to evaluate the emissions of perchloroethylene (tetrachloroethylene) from dry cleaned fabrics to determine: (a) how the introduction of fresh dry cleaning into a home affects the indoor concentration of perchloroethylene, and (b) the effectiveness of 'airing out' dry cleaned clothes in reducing perchloroethylene emissions. Small chamber tests were conducted to determine perchloroethylene emission characteristics for three fabrics at several air exchange rates. Test house studies were conducted to determine the indoor concentration of perchloroethylene due to the placement of dry cleaned clothing in the house. Based on the study results, and assuming that test conditions were representative of normal dry cleaning and consumer practices, the following conclusions were reached. Emissions from freshly dry cleaned clothing cause elevated levels of perchloroethylene in residences. For the three fabrics tested, 'airing out' of dry cleaned clothing by consumers for short time periods (4-8 h) will not be effective in reducing perchloroethylene emissions. Adsorptive surfaces (i.e. sinks) in residences may have a major impact on consumer exposure to perchloroethylene. It is emphasized that these conclusions are based on the results of the study reported. Significant variations in dry cleaning practices and/or in the mix of fabrics and clothing being cleaned could provide different results and conclusions.

  10. Dry phase reactor for generating medical isotopes

    DOEpatents

    Mackie, Thomas Rockwell; Heltemes, Thad Alexander

    2016-05-03

    An apparatus for generating medical isotopes provides for the irradiation of dry-phase, granular uranium compounds which are then dissolved in a solvent for separation of the medical isotope from the irradiated compound. Once the medical isotope is removed, the dissolved compound may be reconstituted in dry granular form for repeated irradiation.

  11. Cold vacuum drying facility 90% design review

    SciTech Connect

    O`Neill, C.T.

    1997-05-02

    This document contains review comment records for the CVDF 90% design review. Spent fuels retrieved from the K Basins will be dried at the CVDF. It has also been recommended that the Multi-Conister Overpacks be welded, inspected, and repaired at the CVD Facility before transport to dry storage.

  12. Improved Energy and Processing Efficiencies of Strawberry Drying Using Sequential Infrared Freeze-Drying Method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strawberries are rich in nutrients but highly perishable. Freeze-drying is an excellent dehydration method for strawberry preservation. However, freeze-drying is an expensive dehydration process due to slow drying rates, high capital operating costs and low energy efficiency. Strawberry slice wei...

  13. Real-time monitoring of drying parameters in semitrailers during peanut drying

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The efficient control of drying parameters is essential to ensure that peanuts are dried at the optimal rate, preserving quality and desired flavor. The present peanut drying process has limitations in means for measuring parameters such as temperature and relative humidity of the air being blown in...

  14. Biological warfare agents.

    PubMed

    Pohanka, Miroslav; Kuca, Kamil

    2010-01-01

    Biological warfare agents are a group of pathogens and toxins of biological origin that can be potentially misused for military or criminal purposes. The present review attempts to summarize necessary knowledge about biological warfare agents. The historical aspects, examples of applications of these agents such as anthrax letters, biological weapons impact, a summary of biological warfare agents and epidemiology of infections are described. The last section tries to estimate future trends in research on biological warfare agents.

  15. High-throughput assay for optimising microbial biological control agent production and delivery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lack of technologies to produce and deliver effective biological control agents (BCAs) is a major barrier to their commercialization. A myriad of variables associated with BCA cultivation, formulation, drying, storage, and reconstitution processes complicates agent quality maximization. An efficie...

  16. Mathematical modelling of cucumber (cucumis sativus) drying

    NASA Astrophysics Data System (ADS)

    Shahari, N.; Hussein, S. M.; Nursabrina, M.; Hibberd, S.

    2014-07-01

    This paper investigates the applicability of using an experiment based mathematical model (empirical model) and a single phase mathematical model with shrinkage to describe the drying curve of cucumis sativus (cucumber). Drying experiments were conducted using conventional air drying and data obtained from these experiments were fitted to seven empirical models using non-linear least square regression based on the Levenberg Marquardt algorithm. The empirical models were compared according to their root mean square error (RMSE), sum of square error (SSE) and coefficient of determination (R2). A logarithmic model was found to be the best empirical model to describe the drying curve of cucumber. The numerical result of a single phase mathematical model with shrinkage was also compared with experiment data for cucumber drying. A good agreement was obtained between the model predictions and the experimental data.

  17. New instruments for dry eye diagnosis.

    PubMed

    Yokoi, Norihiko; Komuro, Aoi; Maruyama, Kunio; Kinoshita, Shigeru

    2005-01-01

    Several non-invasive techniques for dry eye diagnosis have been developed in the past decade. These include quantitative assessment of tear volume, tear film stability, tear dynamics, and integrity of ocular surface epithelium. A combination of meniscometry and interferometry is useful for proving focal dry eye, by confirming whether or not tears at the meniscus have an effect on the ocular surface. Interferometer is also useful to evaluate tear dynamics on soft contact lenses. Fluorophotometry is useful for assessing the severity of dry eye from the view point of corneal epithelial barrier function and measuring the tear turnover rate. Both video-meibography and meibometry are useful for screening meibomian gland dysfunction. The advances in these techniques accumulate knowledge regarding pathophysiology of dry eye and allow precise diagnosis of dry eye. More targeted treatment will become feasible based on the clearer pathophysiology.

  18. EUV extendibility via dry development rinse process

    NASA Astrophysics Data System (ADS)

    Sayan, Safak; Zheng, Tao; De Simone, Danilo; Vandenberghe, Geert

    2016-03-01

    Conventional photoresist processing involves resist coating, exposure, post-exposure bake, development, rinse and spin drying of a wafer. DDRP mitigates pattern collapse by applying a special polymer material (DDRM) which replaces the exposed/developed part of the photoresist material before wafer is spin dried. As noted above, the main mechanism of pattern collapse is the capillary forces governed by surface tension of rinse water and its asymmetrical recession from both sides of the lines during the drying step of the develop process. DDRP essentially eliminates these failure mechanisms by replacing remaining rinse water with DDRM and providing a structural framework that support resist lines from both sides during spin dry process. Dry development rinse process (DDRP) eliminates the root causes responsible for pattern collapse of photoresist line structures. Since these collapse mechanisms are mitigated, without the need for changes in the photoresist itself, achievable resolution of the state-of-the-art EUV photoresists can further be improved.

  19. Inspection of Used Fuel Dry Storage Casks

    SciTech Connect

    Dennis C. Kunerth; Tim McJunkin; Mark McKay; Sasan Bakhtiari

    2012-09-01

    ABSTRACT The U.S. Nuclear Regulatory Commission (NRC) regulates the storage of used nuclear fuel, which is now and will be increasingly placed in dry storage systems. Since a final disposition pathway is not defined, the fuel is expected to be maintained in dry storage well beyond the time frame originally intended. Due to knowledge gaps regarding the viability of current dry storage systems for long term use, efforts are underway to acquire the technical knowledge and tools required to understand the issues and verify the integrity of the dry storage system components. This report summarizes the initial efforts performed by researchers at Idaho National Laboratory and Argonne National Laboratory to identify and evaluate approaches to in-situ inspection dry storage casks. This task is complicated by the design of the current storage systems that severely restrict access to the casks.

  20. Bridging the gaps in systems biology.

    PubMed

    Cvijovic, Marija; Almquist, Joachim; Hagmar, Jonas; Hohmann, Stefan; Kaltenbach, Hans-Michael; Klipp, Edda; Krantz, Marcus; Mendes, Pedro; Nelander, Sven; Nielsen, Jens; Pagnani, Andrea; Przulj, Natasa; Raue, Andreas; Stelling, Jörg; Stoma, Szymon; Tobin, Frank; Wodke, Judith A H; Zecchina, Riccardo; Jirstrand, Mats

    2014-10-01

    Systems biology aims at creating mathematical models, i.e., computational reconstructions of biological systems and processes that will result in a new level of understanding-the elucidation of the basic and presumably conserved "design" and "engineering" principles of biomolecular systems. Thus, systems biology will move biology from a phenomenological to a predictive science. Mathematical modeling of biological networks and processes has already greatly improved our understanding of many cellular processes. However, given the massive amount of qualitative and quantitative data currently produced and number of burning questions in health care and biotechnology needed to be solved is still in its early phases. The field requires novel approaches for abstraction, for modeling bioprocesses that follow different biochemical and biophysical rules, and for combining different modules into larger models that still allow realistic simulation with the computational power available today. We have identified and discussed currently most prominent problems in systems biology: (1) how to bridge different scales of modeling abstraction, (2) how to bridge the gap between topological and mechanistic modeling, and (3) how to bridge the wet and dry laboratory gap. The future success of systems biology largely depends on bridging the recognized gaps.

  1. On the Heat Stability of Amyloid-Based Biological Activity: Insights from Thermal Degradation of Insulin Fibrils

    PubMed Central

    Surmacz-Chwedoruk, Weronika; Malka, Iwona; Bożycki, Łukasz; Nieznańska, Hanna; Dzwolak, Wojciech

    2014-01-01

    Formation of amyloid fibrils in vivo has been linked to disorders such as Alzheimer’s disease and prion-associated transmissible spongiform encephalopathies. One of the characteristic features of amyloid fibrils is the high thermodynamic stability relative both to native and disordered states which is also thought to underlie the perplexingly remarkable heat resistance of prion infectivity. Here, we are comparing high-temperature degradation of native and fibrillar forms of human insulin. Decomposition of insulin amyloid has been studied under helium atmosphere and in the temperature range from ambient conditions to 750°C using thermogravimetry and differential scanning calorimetry coupled to mass spectrometry. While converting native insulin into amyloid does upshift onset of thermal decomposition by ca. 75°C, fibrils remain vulnerable to covalent degradation at temperatures below 300°C, as reflected by mass spectra of gases released upon heating of amyloid samples, as well as morphology and infrared spectra of fibrils subjected to incubation at 250°C. Mass spectra profiles of released gases indicate that degradation of fibrils is much more cooperative than degradation of native insulin. The data show no evidence of water of crystallization trapped within insulin fibrils. We have also compared untreated and heated amyloid samples in terms of capacity to seed daughter fibrils. Kinetic traces of seed-induced insulin fibrillation have shown that the seeding potency of amyloid samples decreases significantly already after exposure to 200°C, even though corresponding electron micrographs indicated persisting fibrillar morphology. Our results suggest that amyloid-based biological activity may not survive extremely high temperature treatments, at least in the absence of other stabilizing factors. PMID:24466022

  2. Hot Dry Rock; Geothermal Energy

    SciTech Connect

    1990-01-01

    The commercial utilization of geothermal energy forms the basis of the largest renewable energy industry in the world. More than 5000 Mw of electrical power are currently in production from approximately 210 plants and 10 000 Mw thermal are used in direct use processes. The majority of these systems are located in the well defined geothermal generally associated with crustal plate boundaries or hot spots. The essential requirements of high subsurface temperature with huge volumes of exploitable fluids, coupled to environmental and market factors, limit the choice of suitable sites significantly. The Hot Dry Rock (HDR) concept at any depth originally offered a dream of unlimited expansion for the geothermal industry by relaxing the location constraints by drilling deep enough to reach adequate temperatures. Now, after 20 years intensive work by international teams and expenditures of more than $250 million, it is vital to review the position of HDR in relation to the established geothermal industry. The HDR resource is merely a body of rock at elevated temperatures with insufficient fluids in place to enable the heat to be extracted without the need for injection wells. All of the major field experiments in HDR have shown that the natural fracture systems form the heat transfer surfaces and that it is these fractures that must be for geothermal systems producing from naturally fractured formations provide a basis for directing the forthcoming but, equally, they require accepting significant location constraints on HDR for the time being. This paper presents a model HDR system designed for commercial operations in the UK and uses production data from hydrothermal systems in Japan and the USA to demonstrate the reservoir performance requirements for viable operations. It is shown that these characteristics are not likely to be achieved in host rocks without stimulation processes. However, the long term goal of artificial geothermal systems developed by systematic

  3. Augmented Dried versus Cryopreserved Amniotic Membrane as an Ocular Surface Dressing

    PubMed Central

    Allen, Claire L.; Clare, Gerry; Stewart, Elizabeth A.; Branch, Matthew J.; McIntosh, Owen D.; Dadhwal, Megha; Dua, Harminder S.; Hopkinson, Andrew

    2013-01-01

    Purpose Dried amniotic membrane (AM) can be a useful therapeutic adjunct in ophthalmic surgery and possesses logistical advantages over cryopreserved AM. Differences in preservation techniques can significantly influence the biochemical composition and physical properties of AM, potentially affecting clinical efficacy. This study was established to investigate the biochemical and structural effects of drying AM in the absence and presence of saccharide lyoprotectants and its biocompatibility compared to cryopreserved material. Methods AM was cryopreserved or dried with and without pre-treatment with trehalose or raffinose and the antioxidant epigallocatechin (EGCG). Structural and visual comparisons were assessed using electron microscopy. Localisation, expression and release of AM biological factors were determined using immunoassays and immunofluorescence. The biocompatibility of the AM preparations co-cultured with corneal epithelial cell (CEC) or keratocyte monolayers were assessed using cell proliferation, cytotoxicity, apoptosis and migration assays. Results Drying devitalised AM epithelium, but less than cryopreservation and cellular damage was reduced in dried AM pre-treated with trehalose or raffinose. Dried AM alone, and with trehalose or raffinose showed greater factor retention efficiencies and bioavailability compared to cryopreserved AM and demonstrated a more sustained biochemical factor time release in vitro. Cellular health assays showed that dried AM with trehalose or raffinose are compatible and superior substrates compared to cryopreserved AM for primary CEC expansion, with increased proliferation and reduced LDH and caspase-3 levels. This concept was supported by improved wound healing in an immortalised human CEC line (hiCEC) co-cultured with dried and trehalose or raffinose membranes, compared to cryopreserved and fresh AM. Conclusions Our modified preservation process and our resultant optimised dried AM has enhanced structural properties

  4. Cryofixation and ultra-low-temperature freeze-drying as a preparative technique for TEM.

    PubMed

    Livesey, S A; del Campo, A A; McDowall, A W; Stasny, J T

    1991-02-01

    We have developed cryofixation and ultra-low-temperature molecular distillation drying as a method for preparing biological samples for electron microscopic analysis. To validate this approach, we have investigated the relationship between the drying characteristics and ice phases present within frozen samples. Two sample types were investigated. In the first, pure deuterium oxide (D2O), or heavy water, was vapour condensed under vacuum conditions onto a gold-coated copper sample holder held at -175 or -110 degrees C. Additionally, D2O was slow-rate cooled from room temperature under an ultra-pure dry nitrogen gas atmosphere. The second sample type was rat liver biopsies from animals after 5 days of feeding with D2O loaded water and ultra-rapid cooling by metal-mirror cryofixation. Ice forms present in the latter samples, determined by electron diffraction of frozen-hydrated cryosections, were amorphous, cubic, and hexagonal. Drying of samples was achieved using a molecular distillation configuration with continuous, microprocessor-controlled sample heating. The vacuum contents of the drying column were monitored by residual gas analysis (RGA) throughout the drying cycle. D2O vapour in the vacuum chamber, as analysed by RGA, was found to increase in a phasic manner across a broad temperature range. These phases had characteristic onset temperatures and could be removed sequentially. For condensed D2O samples, these onset temperatures were -160, -148, -125 and -90 degrees C. Rat liver samples also demonstrated phasic drying patterns which were more complex than those detected with pure D2O samples. Ultrastructural analysis of samples cryofixed and dried in this manner demonstrated a morphology consistent with the ice phases demonstrated in the frozen-hydrated cryosections. This, together with the RGA results, suggests the absence of devitrification or ice crystal growth during the drying procedure.

  5. Advancing microwave technology for dehydration processing of biologics.

    PubMed

    Cellemme, Stephanie L; Van Vorst, Matthew; Paramore, Elisha; Elliott, Gloria D

    2013-10-01

    Our prior work has shown that microwave processing can be effective as a method for dehydrating cell-based suspensions in preparation for anhydrous storage, yielding homogenous samples with predictable and reproducible drying times. In the current work an optimized microwave-based drying process was developed that expands upon this previous proof-of-concept. Utilization of a commercial microwave (CEM SAM 255, Matthews, NC) enabled continuous drying at variable low power settings. A new turntable was manufactured from Ultra High Molecular Weight Polyethylene (UHMW-PE; Grainger, Lake Forest, IL) to provide for drying of up to 12 samples at a time. The new process enabled rapid and simultaneous drying of multiple samples in containment devices suitable for long-term storage and aseptic rehydration of the sample. To determine sample repeatability and consistency of drying within the microwave cavity, a concentration series of aqueous trehalose solutions were dried for specific intervals and water content assessed using Karl Fischer Titration at the end of each processing period. Samples were dried on Whatman S-14 conjugate release filters (Whatman, Maidestone, UK), a glass fiber membrane used currently in clinical laboratories. The filters were cut to size for use in a 13 mm Swinnex(®) syringe filter holder (Millipore(™), Billerica, MA). Samples of 40 μL volume could be dehydrated to the equilibrium moisture content by continuous processing at 20% with excellent sample-to-sample repeatability. The microwave-assisted procedure enabled high throughput, repeatable drying of multiple samples, in a manner easily adaptable for drying a wide array of biological samples. Depending on the tolerance for sample heating, the drying time can be altered by changing the power level of the microwave unit. PMID:24835259

  6. Advancing Microwave Technology for Dehydration Processing of Biologics

    PubMed Central

    Cellemme, Stephanie L.; Van Vorst, Matthew; Paramore, Elisha

    2013-01-01

    Our prior work has shown that microwave processing can be effective as a method for dehydrating cell-based suspensions in preparation for anhydrous storage, yielding homogenous samples with predictable and reproducible drying times. In the current work an optimized microwave-based drying process was developed that expands upon this previous proof-of-concept. Utilization of a commercial microwave (CEM SAM 255, Matthews, NC) enabled continuous drying at variable low power settings. A new turntable was manufactured from Ultra High Molecular Weight Polyethylene (UHMW-PE; Grainger, Lake Forest, IL) to provide for drying of up to 12 samples at a time. The new process enabled rapid and simultaneous drying of multiple samples in containment devices suitable for long-term storage and aseptic rehydration of the sample. To determine sample repeatability and consistency of drying within the microwave cavity, a concentration series of aqueous trehalose solutions were dried for specific intervals and water content assessed using Karl Fischer Titration at the end of each processing period. Samples were dried on Whatman S-14 conjugate release filters (Whatman, Maidestone, UK), a glass fiber membrane used currently in clinical laboratories. The filters were cut to size for use in a 13 mm Swinnex® syringe filter holder (Millipore™, Billerica, MA). Samples of 40 μL volume could be dehydrated to the equilibrium moisture content by continuous processing at 20% with excellent sample-to-sample repeatability. The microwave-assisted procedure enabled high throughput, repeatable drying of multiple samples, in a manner easily adaptable for drying a wide array of biological samples. Depending on the tolerance for sample heating, the drying time can be altered by changing the power level of the microwave unit. PMID:24835259

  7. Effect of drying conditions on drying kinetics and quality of aromatic Pandanus amaryllifolius leaves.

    PubMed

    Rayaguru, Kalpana; Routray, Winny

    2010-12-01

    Pandanus amaryllifolius is a plant with aromatic leaves, which impart the characteristic flavour of aromatic rice. The quality of aromatic Pandanus leaves dried at low temperature (35 °C) and low RH (27%) in a heat pump dryer was evaluated and compared with those obtained from hot air drying at 45 °C. Thin-layer drying kinetics has been studied for both the conditions. To determine the kinetic parameters, the drying data were fitted to various semi-theoretical models. The goodness of fit was determined using the coefficient of determination, reduced chi square, and root mean square error. Aroma, colour, and overall acceptability determination of fresh and dried leaves were made using sensory evaluation. Drying of leaves took place mainly under the falling-rate period. The Page equation was found to be best among the proposed models to describe the thin-layer drying of Pandanus leaves with higher coefficient of determination. The effective moisture diffusivity values were also determined. The effect of low RH was prominent during the initial drying when the product was moist. The effect of temperature was prominent in the later part of drying, which acted as a driving force for moisture diffusion and hence the total drying time was reduced. Retention of aromatic compound 2-acetyl-1-pyrroline content was more in low temperature dried samples with higher sensory scores. PMID:23572703

  8. Sun drying of seedless and seeded grapes.

    PubMed

    Doymaz, Ibrahim

    2012-04-01

    In this study, sun drying behaviour of seedless and seeded grapes was investigated. The drying study showed that the times taken for drying of seedless and seeded grapes of berry size of 1.72 cm and 2.20 cm thicknesses from the initial moisture contents of 78.2% and 79.5% (w.b.) to final moisture content of around 22% (w.b.) were 176 and 228 h in open sun drying, respectively. The drying data were fitted to 12 thin-layer drying models. The performance of these models were compared using the determination of coefficient (R(2)), mean relative percent error (P), reduced chi-square (χ (2)) and root mean square error (RMSE) between the observed and predicted moisture ratios. The results showed that Midilli et al. model was found to satisfactorily describe the sun drying curves of seedless and seeded grapes. The effective moisture diffusivity values were estimated from Fick's diffusion model by 1.02 × 10(-11) and 1.66 × 10(-11) m(2)/s for seeded and seedless grapes. PMID:23572844

  9. Acoustically enhanced heat exchange and drying apparatus

    DOEpatents

    Bramlette, T.T.; Keller, J.O.

    1987-07-10

    A heat transfer drying apparatus includes an acoustically augmented heat transfer chamber for receiving material to be dried. The chamber includes a first heat transfer gas inlet, a second heat transfer gas inlet, a material inlet, and a gas outlet which also serves as a dried material and gas outlet. A non-pulsing first heat transfer gas source provides a first drying gas to the acoustically augmented heat transfer chamber through the first heat transfer gas inlet. A valveless, continuous second heat transfer gas source provides a second drying gas to the acoustically augmented heat transfer chamber through the second heat transfer gas inlet. The second drying gas also generates acoustic waves which bring about acoustical coupling with the gases in the acoustically augmented heat transfer chamber. The second drying gas itself oscillates at an acoustic frequency of approximately 180 Hz due to fluid mechanical motion in the gas. The oscillations of the second heat transfer gas coupled to the first heat transfer gas in the acoustically augmented heat transfer chamber enhance heat and mass transfer by convection within the chamber. 3 figs.

  10. Biological conversion system

    DOEpatents

    Scott, C.D.

    A system for bioconversion of organic material comprises a primary bioreactor column wherein a biological active agent (zymomonas mobilis) converts the organic material (sugar) to a product (alcohol), a rejuvenator column wherein the biological activity of said biological active agent is enhanced, and means for circulating said biological active agent between said primary bioreactor column and said rejuvenator column.

  11. Learning Biology by Designing

    ERIC Educational Resources Information Center

    Janssen, Fred; Waarlo, Arend Jan

    2010-01-01

    According to a century-old tradition in biological thinking, organisms can be considered as being optimally designed. In modern biology this idea still has great heuristic value. In evolutionary biology a so-called design heuristic has been formulated which provides guidance to researchers in the generation of knowledge about biological systems.…

  12. 7 CFR 58.250 - Dry whole milk.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 3 2013-01-01 2013-01-01 false Dry whole milk. 58.250 Section 58.250 Agriculture... Products Bearing Usda Official Identification § 58.250 Dry whole milk. Dry whole milk in commercial bulk... Grades of Dry Whole Milk. Quality requirements for dry whole milk in consumer packages shall be for...

  13. 7 CFR 58.250 - Dry whole milk.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 3 2011-01-01 2011-01-01 false Dry whole milk. 58.250 Section 58.250 Agriculture... Products Bearing Usda Official Identification § 58.250 Dry whole milk. Dry whole milk in commercial bulk... Grades of Dry Whole Milk. Quality requirements for dry whole milk in consumer packages shall be for...

  14. 7 CFR 58.250 - Dry whole milk.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 3 2014-01-01 2014-01-01 false Dry whole milk. 58.250 Section 58.250 Agriculture... Products Bearing Usda Official Identification § 58.250 Dry whole milk. Dry whole milk in commercial bulk... Grades of Dry Whole Milk. Quality requirements for dry whole milk in consumer packages shall be for...

  15. 7 CFR 58.250 - Dry whole milk.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Dry whole milk. 58.250 Section 58.250 Agriculture... Products Bearing Usda Official Identification § 58.250 Dry whole milk. Dry whole milk in commercial bulk... Grades of Dry Whole Milk. Quality requirements for dry whole milk in consumer packages shall be for...

  16. 7 CFR 58.250 - Dry whole milk.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 3 2012-01-01 2012-01-01 false Dry whole milk. 58.250 Section 58.250 Agriculture... Products Bearing Usda Official Identification § 58.250 Dry whole milk. Dry whole milk in commercial bulk... Grades of Dry Whole Milk. Quality requirements for dry whole milk in consumer packages shall be for...

  17. 46 CFR 154.1150 - Distribution of dry chemical.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Distribution of dry chemical. 154.1150 Section 154.1150... Firefighting System: Dry Chemical § 154.1150 Distribution of dry chemical. (a) All locations on the above deck... chemical hand hose lines; or (2) At least one dry chemical hand hose line and one dry chemical monitor....

  18. 46 CFR 154.1150 - Distribution of dry chemical.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Distribution of dry chemical. 154.1150 Section 154.1150... Firefighting System: Dry Chemical § 154.1150 Distribution of dry chemical. (a) All locations on the above deck... chemical hand hose lines; or (2) At least one dry chemical hand hose line and one dry chemical monitor....

  19. 46 CFR 154.1150 - Distribution of dry chemical.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Distribution of dry chemical. 154.1150 Section 154.1150... Firefighting System: Dry Chemical § 154.1150 Distribution of dry chemical. (a) All locations on the above deck... chemical hand hose lines; or (2) At least one dry chemical hand hose line and one dry chemical monitor....

  20. Mechanisms of deterioration of nutrients. [of freeze dried foods

    NASA Technical Reports Server (NTRS)

    Karel, M.; Flink, J. M.

    1976-01-01

    Methods which produce freeze dried foods of improved quality were examined with emphasis on storage stability. Specific topics discussed include: microstructure of freeze dried systems, investigation of structural changes in freeze dried systems, artificial food matrices, osmotic preconcentration to yield improved quality freeze dried fruits, and storage stability of osmotically preconcentrated freeze dried fruits.

  1. Airless drying -- Developments since IDS'94

    SciTech Connect

    Stubbing, T.J.

    1999-09-01

    Since its introduction to IDS'94 delegates, significant progress has been made with the development of airless drying technology. The ceramic industry internationally is beginning to benefit from both the energy use and drying time reductions it achieves, while on the basis of further theoretical work carried out since 1993 other industries, including the bioenergy sector, should also soon begin to exploit its advantages. As global warming becomes a reality and oil reserves decline, superheated steam drying and gasification of biomass will contribute to the mitigation of those problems.

  2. Cold vacuum drying facility site evaluation report

    SciTech Connect

    Diebel, J.A.

    1996-03-11

    In order to transport Multi-Canister Overpacks to the Canister Storage Building they must first undergo the Cold Vacuum Drying process. This puts the design, construction and start-up of the Cold Vacuum Drying facility on the critical path of the K Basin fuel removal schedule. This schedule is driven by a Tri-Party Agreement (TPA) milestone requiring all of the spent nuclear fuel to be removed from the K Basins by December, 1999. This site evaluation is an integral part of the Cold Vacuum Drying design process and must be completed expeditiously in order to stay on track for meeting the milestone.

  3. Holographic measurements of fresh dry bone elasticity

    NASA Astrophysics Data System (ADS)

    Silvennoinen, Raimo; Nygren, Kaarlo; Karna, Markku; Karna, Kari

    1992-08-01

    To compare the elasticity of bones covered with soft tissue and the elasticity of defleshed and dried bones, we used sampling screws to make the surface movements of the bones visible through the soft tissue. We compared fresh and dry European moose skulls before and after skinning. External forces were focused on the skull bones through the pedicles. A high correlation in fringe orientation was observed in the case of thick bone structures with rigid interdigited sutures. We also compared compression dynamics of fresh and dry moose antler cubes.

  4. Translational environmental biology: cell biology informing conservation.

    PubMed

    Traylor-Knowles, Nikki; Palumbi, Stephen R

    2014-05-01

    Typically, findings from cell biology have been beneficial for preventing human disease. However, translational applications from cell biology can also be applied to conservation efforts, such as protecting coral reefs. Recent efforts to understand the cell biological mechanisms maintaining coral health such as innate immunity and acclimatization have prompted new developments in conservation. Similar to biomedicine, we urge that future efforts should focus on better frameworks for biomarker development to protect coral reefs.

  5. Synthetic biology: insights into biological computation.

    PubMed

    Manzoni, Romilde; Urrios, Arturo; Velazquez-Garcia, Silvia; de Nadal, Eulàlia; Posas, Francesc

    2016-04-18

    Organisms have evolved a broad array of complex signaling mechanisms that allow them to survive in a wide range of environmental conditions. They are able to sense external inputs and produce an output response by computing the information. Synthetic biology attempts to rationally engineer biological systems in order to perform desired functions. Our increasing understanding of biological systems guides this rational design, while the huge background in electronics for building circuits defines the methodology. In this context, biocomputation is the branch of synthetic biology aimed at implementing artificial computational devices using engineered biological motifs as building blocks. Biocomputational devices are defined as biological systems that are able to integrate inputs and return outputs following pre-determined rules. Over the last decade the number of available synthetic engineered devices has increased exponentially; simple and complex circuits have been built in bacteria, yeast and mammalian cells. These devices can manage and store information, take decisions based on past and present inputs, and even convert a transient signal into a sustained response. The field is experiencing a fast growth and every day it is easier to implement more complex biological functions. This is mainly due to advances in in vitro DNA synthesis, new genome editing tools, novel molecular cloning techniques, continuously growing part libraries as well as other technological advances. This allows that digital computation can now be engineered and implemented in biological systems. Simple logic gates can be implemented and connected to perform novel desired functions or to better understand and redesign biological processes. Synthetic biological digital circuits could lead to new therapeutic approaches, as well as new and efficient ways to produce complex molecules such as antibiotics, bioplastics or biofuels. Biological computation not only provides possible biomedical and

  6. Translational environmental biology: cell biology informing conservation.

    PubMed

    Traylor-Knowles, Nikki; Palumbi, Stephen R

    2014-05-01

    Typically, findings from cell biology have been beneficial for preventing human disease. However, translational applications from cell biology can also be applied to conservation efforts, such as protecting coral reefs. Recent efforts to understand the cell biological mechanisms maintaining coral health such as innate immunity and acclimatization have prompted new developments in conservation. Similar to biomedicine, we urge that future efforts should focus on better frameworks for biomarker development to protect coral reefs. PMID:24766840

  7. Synthetic biology: insights into biological computation.

    PubMed

    Manzoni, Romilde; Urrios, Arturo; Velazquez-Garcia, Silvia; de Nadal, Eulàlia; Posas, Francesc

    2016-04-18

    Organisms have evolved a broad array of complex signaling mechanisms that allow them to survive in a wide range of environmental conditions. They are able to sense external inputs and produce an output response by computing the information. Synthetic biology attempts to rationally engineer biological systems in order to perform desired functions. Our increasing understanding of biological systems guides this rational design, while the huge background in electronics for building circuits defines the methodology. In this context, biocomputation is the branch of synthetic biology aimed at implementing artificial computational devices using engineered biological motifs as building blocks. Biocomputational devices are defined as biological systems that are able to integrate inputs and return outputs following pre-determined rules. Over the last decade the number of available synthetic engineered devices has increased exponentially; simple and complex circuits have been built in bacteria, yeast and mammalian cells. These devices can manage and store information, take decisions based on past and present inputs, and even convert a transient signal into a sustained response. The field is experiencing a fast growth and every day it is easier to implement more complex biological functions. This is mainly due to advances in in vitro DNA synthesis, new genome editing tools, novel molecular cloning techniques, continuously growing part libraries as well as other technological advances. This allows that digital computation can now be engineered and implemented in biological systems. Simple logic gates can be implemented and connected to perform novel desired functions or to better understand and redesign biological processes. Synthetic biological digital circuits could lead to new therapeutic approaches, as well as new and efficient ways to produce complex molecules such as antibiotics, bioplastics or biofuels. Biological computation not only provides possible biomedical and

  8. Relationship between moisture content and electrical impedance of carrot slices during drying

    NASA Astrophysics Data System (ADS)

    Kertész, Ákos; Hlaváčová, Zuzana; Vozáry, Eszter; Staroňová, Lenka

    2015-01-01

    Electrical properties of food materials can give information about the inner structure and physiological state of biological tissues. Generally, the process of drying of fruits and vegetables is followed by weight loss. The aim of this study was to measure the impedance spectra of carrot slices during drying and to correlate impedance parameters to moisture content in different drying periods. Cylindrical slices were cut out from the carrot root along the axis. The slices were dried in a Venticell 111 air oven at 50°C. The weight of the slices was measured with a Denver SI-603 electronic analytical and precision balance. The weighing of the samples was performed every 30 min at the beginning of drying and every 60 min after the process. The moisture content of the samples was calculated on wet basis. The magnitude and phase angle of electrical impedance of the slices were measured with HP 4284A and 4285A precision LCR meters in the frequency range from 30 Hz to 1 MHz and from 75 kHz to 30 MHz, respectively, at voltage 1 V. The impedance measurement was performed after weighting. The change in the magnitude of impedance during drying showed a good correlation with the change in the moisture content.

  9. Drying and Storage Effects on Poly(ethylene glycol) Hydrogel Mechanical Properties and Bioactivity

    PubMed Central

    Luong, P.T.; Browning, M.B.; Bixler, R.S.; Cosgriff-Hernandez, E.

    2014-01-01

    Hydrogels based on poly(ethylene glycol) (PEG) are increasingly used in biomedical applications due to the ability to control cell-material interactions by tuning hydrogel physical and biological properties. Evaluation of stability after drying and storage are critical in creating an off-the-shelf biomaterial that functions in vivo according to original specifications. However, there has not been a study that systematically investigates the effects of different drying conditions and hydrogel compositional variables. In the first part of this study, PEG-diacrylate hydrogels underwent common processing procedures (vacuum-drying, lyophilizing, hydrating then vacuum-drying) and the effect of this processing on the mechanical properties and swelling ratios was measured. Significant changes in compressive modulus, tensile modulus, and swelling ratio only occurred for select processed hydrogels. No consistent trends were observed after processing for any of the formulations tested. The effect of storage conditions on cell adhesion and spreading on collagen- and streptococcal collagen-like protein (Scl2-2)-PEG-diacrylamide hydrogels was then evaluated to characterize bioactivity retention after storage. Dry storage conditions preserved bioactivity after 6 weeks of storage; whereas, storage in PBS significantly reduced bioactivity. This loss of bioactivity was attributed to ester hydrolysis of the protein linker, acrylate-PEG-N-hydroxysuccinimide. These studies demonstrate that these processing methods and dry storage conditions may be used to prepare bioactive PEG hydrogel scaffolds with recoverable functionality after storage. PMID:24123725

  10. Systems interface biology

    PubMed Central

    Doyle, Francis J; Stelling, Jörg

    2006-01-01

    The field of systems biology has attracted the attention of biologists, engineers, mathematicians, physicists, chemists and others in an endeavour to create systems-level understanding of complex biological networks. In particular, systems engineering methods are finding unique opportunities in characterizing the rich behaviour exhibited by biological systems. In the same manner, these new classes of biological problems are motivating novel developments in theoretical systems approaches. Hence, the interface between systems and biology is of mutual benefit to both disciplines. PMID:16971329

  11. What is Systems Biology?

    PubMed Central

    Breitling, Rainer

    2010-01-01

    Systems biology is increasingly popular, but to many biologists it remains unclear what this new discipline actually encompasses. This brief personal perspective starts by outlining the asthetic qualities that motivate systems biologists, discusses which activities do not belong to the core of systems biology, and finally explores the crucial link with synthetic biology. It concludes by attempting to define systems biology as the research endeavor that aims at providing the scientific foundation for successful synthetic biology. PMID:21423352

  12. Fuel-Cell Structure Prevents Membrane Drying

    NASA Technical Reports Server (NTRS)

    Mcelroy, J.

    1986-01-01

    Embossed plates direct flows of reactants and coolant. Membrane-type fuel-cell battery has improved reactant flow and heat removal. Compact, lightweight battery produces high current and power without drying of membranes.

  13. Dry eye: diagnosis and current treatment strategies.

    PubMed

    O'Brien, Paul D; Collum, Louis M T

    2004-07-01

    One in four patients attending ophthalmic clinics report symptoms of dry eye, making it one of the most common complaints seen by ophthalmologists. Aqueous-layer deficiency is the most common form of dry eye and is frequently caused by decreased secretion of tears by the lacrimal glands. Evaporative dry eye is often secondary to meibomian gland disease and results in a defective lipid layer. Tear replacement or preservation using artificial tears and/or punctal occlusion are the mainstay of treatment. Newer forms of therapy were designed to modify the underlying disease process. These include the use of topical cyclosporin A, autologous serum, and sodium hyaluronate drops, which suppress underlying inflammation, provide growth factors, and prevent the onset of squamous metaplasia in ocular surface epithelium. Hormonal therapy might have a role in the future of dry eye therapy.

  14. Recent Advances in Nanostructured Biomimetic Dry Adhesives

    PubMed Central

    Pattantyus-Abraham, Andras; Krahn, Jeffrey; Menon, Carlo

    2013-01-01

    The relatively large size of the gecko and its ability to climb a multitude of structures with ease has often been cited as the inspiration upon which the field of dry adhesives is based. Since 2010, there have been many advances in the field of dry adhesives with much of the new research focusing on developing nanoscale and hierarchical features in a concentrated effort to develop synthetic gecko-like dry adhesives which are strong, durable, and self-cleaning. A brief overview of the geckos and the hairs which it uses to adhere to many different surfaces is provided before delving into the current methods and materials used to fabricate synthetic gecko hairs. A summary of the recently published literature on bio-inspired, nanostructured dry adhesives is presented with an emphasis being placed on fabrication techniques. PMID:25023409

  15. Cold vacuum drying facility design requirements

    SciTech Connect

    Irwin, J.J.

    1997-09-24

    This release of the Design Requirements Document is a complete restructuring and rewrite to the document previously prepared and released for project W-441 to record the design basis for the design of the Cold Vacuum Drying Facility.

  16. Hydrothermal regimes of the dry active layer

    NASA Astrophysics Data System (ADS)

    Ishikawa, Mamoru; Zhang, Yinsheng; Kadota, Tsutomu; Ohata, Tetsuo

    2006-04-01

    Evaporation and condensation in the soil column clearly influence year-round nonconductive heat transfer dynamics in the dry active layer underlying semiarid permafrost regions. We deduced this from heat flux components quantified using state-of-the-art micrometeorological data sets obtained in dry and moist summers and in winters with various snow cover depths. Vapor moves easily through large pores, some of which connect to the atmosphere, allowing (1) considerable active layer warming driven by pipe-like snowmelt infiltration, and (2) direct vapor linkage between atmosphere and deeper soils. Because of strong adhesive forces, water in the dry active layer evaporates with great difficulty. The fraction of latent heat to total soil heat storage ranged from 26 to 45% in dry and moist summers, respectively. These values are not negligible, despite being smaller than those of arctic wet active layer, in which only freezing and thawing were considered.

  17. Mechanisms of Drying of Skin Forming Materials

    NASA Astrophysics Data System (ADS)

    Hassan, Haydar Mahmood

    Available from UMI in association with The British Library. The literature relating to evaporation from single droplets of pure liquids, and to the drying of droplets containing solids and of droplet sprays has been reviewed. The heat and mass transfer rates for a single droplet suspended from a nozzle were studied within a 42mm I.D. horizontal wind tunnel designed to supply hot dry air, to simulate conditions encountered in practical spray dryer. A novel rotating glass nozzle was developed to facilitate direct measurements of droplet weight and core temperature. This design minimised heat conduction through the nozzle. Revised correlations were obtained for heat and mass transfer coefficients, for evaporation from pure water droplets suspended from a rotating nozzle. (UNFORMATTED TABLE OR EQUATION FOLLOWS)eqalign {rm Nu&= rm 2.0 + 0.27 ({1over B})^{0.18}Re^{0.5}Pr ^{0.33}crrm Sh&= rm 2.0 + 0.575({Ta-Ts over Tamb})^{ -0.04}Re^{0.5}Sc^{0.33 }cr}(TABLE/EQUATION ENDS)Experimental drying studies were carried out on single droplets of different types of skin-forming materials, namely, custard, starch, gelatin, skim milk and fructose at air temperatures ranging from 19^circC to 198 ^circC. Dried crusts were recovered and examined by Scanning Electron Microscopy. Skin-forming materials were classified into three types according to the mechanisms of skin formation. In the first type (typified by droplets of custard and starch) skin formed due to gelatinisation at high temperatures. Increasing the drying temperature resulted in increased crust resistance to mass transfer due to increased granule swelling and the crust resistance was completely transferred to a skin resistance at drying temperatures >150 ^circC. In the second type e.g. gelatin droplets the skin formed immediately drying had taken place at any drying temperature. At drying temperature >60^circC a more resistant skin was formed. In the third type (typified by droplets of skim milk and fructose) the skin

  18. High strength air-dried aerogels

    SciTech Connect

    Coronado, Paul R.; Satcher, Jr., Joe H.

    2012-11-06

    A method for the preparation of high strength air-dried organic aerogels. The method involves the sol-gel polymerization of organic gel precursors, such as resorcinol with formaldehyde (RF) in aqueous solvents with R/C ratios greater than about 1000 and R/F ratios less than about 1:2.1. Using a procedure analogous to the preparation of resorcinol-formaldehyde (RF) aerogels, this approach generates wet gels that can be air dried at ambient temperatures and pressures. The method significantly reduces the time and/or energy required to produce a dried aerogel compared to conventional methods using either supercritical solvent extraction. The air dried gel exhibits typically less than 5% shrinkage.

  19. Subsurface Salts in Antarctic Dry Valley Soils

    NASA Technical Reports Server (NTRS)

    Englert, P.; Bishop, J. L.; Gibson, E. K.; Koeberl, C.

    2013-01-01

    The distribution of water-soluble ions, major and minor elements, and other parameters were examined to determine the extent and effects of chemical weathering on cold desert soils. Patterns at the study sites support theories of multiple salt forming processes, including marine aerosols and chemical weathering of mafic minerals. Periodic solar-mediated ionization of atmospheric nitrogen might also produce high nitrate concentrations found in older sediments. Chemical weathering, however, was the major contributor of salts in Antarctic Dry Valleys. The Antarctic Dry Valleys represent a unique analog for Mars, as they are extremely cold and dry desert environments. Similarities in the climate, surface geology, and chemical properties of the Dry Valleys to that of Mars imply the possible presence of these soil formation mechanisms on Mars, other planets and icy satellites.

  20. Dry Eye in Pediatric Contact Lens Wearers

    PubMed Central

    Greiner, Katie L.; Walline, Jeffrey J.

    2015-01-01

    Objectives To determine whether children who wear contact lenses truly have fewer dry eye complaints than adults. Methods Ninety-four pediatric contact lens wearers, ages 8 to 14 years, were recruited and given the Contact Lens Dry Eye Questionnaire (CLDEQ) short form. The survey is designed to diagnose dry eye syndrome by obtaining information on the frequency of dryness and light sensitivity and their corresponding intensity levels within the first two hours of putting in the lenses, in the middle of the day, and at the end of the day. The responses were scored by multiplying the frequency by the average intensity and a constant. A composite score was calculated by subtracting the photophobia score from the dryness score, and the results were compared to adult samples from the literature. The questionnaire also asked whether the subject thought he/she had dry eyes while wearing contact lenses. Subjects that thought they had dry eyes and had a CLDEQ composite score >0.03 were diagnosed with dry eye. Subjects who were unsure if they dry eye or said they did not have dry eye but scored >1.29 were also diagnosed with dry eye. Results The average (± SD) age of the sample was 11.7 ± 1.5 years, 56.4% were female, 59.6% were white, and 19.1% were black. The mean (± SD) CLDEQ composite score was 0.25 ±0.50 (range= -1.20 to 1.45). In the literature, the adult mean (± SD) CLDEQ composite score was 1.02 ±0.80 (range= -0.74 to 4.50). Of the 94 surveys collected, 4.3% of children were categorized with dry eye compared to 56.2% of adults who completed the CLDEQ survey in the adult study. Conclusions Pediatric contact lens wearers have fewer complaints about dry eyes than adult contact lens wearers, which may be due to improved tear film, differences in reporting of symptoms, or modality of contact lens wear. PMID:21060258

  1. Teaching Biology around Themes: Teach Proteins and DNA Together.

    ERIC Educational Resources Information Center

    Offner, Susan

    1992-01-01

    Proposes as a unifying theme for high school biology the question of "how chromosomes determine what we are." Describes a sequence of lessons in which students learn about proteins, enzymes, and amino acids. Includes three dry laboratory exercises to demonstrate the DNA sequences for sickle cell anemia and cystic fibrosis. (MDH)

  2. Solar Energy Education. Renewable energy activities for biology

    SciTech Connect

    Not Available

    1982-01-01

    An instructional aid for teachers is presented that will allow biology students the opportunity to learn about renewable energy sources. Some of the school activities include using leaves as collectors of solar energy, solar energy stored in wood, and a fuel value test for green and dry woods. A study of organic wastes as a source of fuel is included. (BCS)

  3. Biological control of post-harvest late blight of potatoes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction of US-8 genotypes of Phytophthora infestans has coincided with an increase in severity of potato late blight in North America. As alternatives to chemical fungicides, 18 bacterial strains patented as biological control agents (BCA) of both sprouting and Fusarium dry rot were cultivated...

  4. Dry-Enzyme Test For Gaseous Chemicals

    NASA Technical Reports Server (NTRS)

    Barzana, Eduardo; Karel, Marcus; Klibanov, Alexander

    1990-01-01

    Simple, dry-chemical test detects ethanol in human breath. Method of test also adapted to detection of such toxic chemicals as formaldehyde in airstreams. Used qualitatively to detect chemical compounds above present level; for example, ethanol above legal level for driving. Also used to indicate quantitatively concentrations of compounds. Involves dry enzyme and color indicator. Adapted to detect any gaseous compound transformed by enzymes to produce change evident to human eye or to instrument.

  5. R and D needs -- Drying of sludges

    SciTech Connect

    Kasakura, T.; Hasatani, M.

    1996-10-01

    Sludge management is a very important environmental issue in many industrialized countries, because its generated volume is the largest in all generated wastes. In the sludge management field, the role of drying is becoming more important as sludge disposal becomes more difficult. In this paper, the present status of drying of construction sludge, food industry sludge and municipal sludge are mentioned as concrete examples. To respond to these needs, it is necessary to advance further R and D.

  6. Insightful understanding of the role of clay topology on the stability of biomimetic hybrid chitosan-clay thin films and CO2-dried porous aerogel microspheres.

    PubMed

    Frindy, Sana; Primo, Ana; Qaiss, Abou El Kacem; Bouhfid, Rachid; Lahcini, Mohamed; Garcia, Hermenegildo; Bousmina, Mosto; El Kadib, Abdelkrim

    2016-08-01

    Three natural clay-based microstructures, namely layered montmorillonite (MMT), nanotubular halloysite (HNT) and micro-fibrillar sepiolite (SP) were used for the synthesis of hybrid chitosan-clay thin films and porous aerogel microspheres. At a first glance, a decrease in the viscosity of the three gel-forming solutions was noticed as a result of breaking the mutual polymeric chains interaction by the clay microstructure. Upon casting, chitosan-clay films displayed enhanced hydrophilicity in the order CSdrying as the most hydrophilic CS-SP microspheres face the highest shrinkage, resulting in a lowest specific surface area compared to CS-HNT and CS-MMT. Chitosan-clay exhibits enhanced thermal properties with the degradation delayed in the order CSdrying and under hydrothermal conditions. The knowledge gained from this rational design will constitute a guideline toward the preparation of ultra-stable, practically-optimized food

  7. Contextual view of building 110 with dry dock 1 visible ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of building 110 with dry dock 1 visible on left; camera facing southeast. - Mare Island Naval Shipyard, Pump House, California Avenue, east side between Dry Dock 1 & Dry Dock 2, near Ninth Street, Vallejo, Solano County, CA

  8. Contextual view of building 110 with dry dock 2 in ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Contextual view of building 110 with dry dock 2 in foreground; camera facing northeast. - Mare Island Naval Shipyard, Pump House, California Avenue, east side between Dry Dock 1 & Dry Dock 2, near Ninth Street, Vallejo, Solano County, CA

  9. 46 CFR 154.1150 - Distribution of dry chemical.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... chemical hand hose lines; or (2) At least one dry chemical hand hose line and one dry chemical monitor. (b) At least one dry chemical storage unit and hand hose line or monitor must be at the after end of...

  10. 46 CFR 154.1150 - Distribution of dry chemical.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... chemical hand hose lines; or (2) At least one dry chemical hand hose line and one dry chemical monitor. (b) At least one dry chemical storage unit and hand hose line or monitor must be at the after end of...

  11. Using solar dryers to dry clay bricks

    SciTech Connect

    Bernal, J.A.; Wicker, R.B.

    1996-12-31

    Experiments using a small-scale solar dryer have been performed to determine the effect of incorporating solar dryers in the pre-firing stage of clay brick production. A comparison of brick moisture content over time is presented for dry bricks that underwent additional drying either naturally through direct exposure, in convection ovens set at 65.6 C and 104 C, in the solar dryer, or sealed in plastic bags. The ambient temperature and relative humidity were monitored along with the solar dryer temperature. Results indicated the solar dryer removed from one to two percent more moisture than natural drying, but removed less moisture than did the ovens. A similar comparison of wet bricks naturally dried, oven dried, and placed in the solar dryer for periods of five and seven days is also presented. The solar dryer reduced the amount of time required for bricks to be dried to a specified moisture content and increased the amount of moisture removed for a given amount of time.

  12. Freeze-drying of lactic acid bacteria.

    PubMed

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery.

  13. Natural denitrification in drying process of dew

    SciTech Connect

    Takenaka, Norimichi; Suzue, Takahiko; Ohira, Kingo; Bandow, Hiroshi; Maeda, Yasuki; Morikawa, Tazuko

    1999-05-01

    This report is the first observation of natural chemical denitrification in the drying process of dew. Nitrogen compounds released in the atmosphere are considered to be subjected to oxidation to form nitric acid by the chemical process so far. The results here show that nitrous acid is reduced to N{sub 2} by drying of dew. Dew was collected at Osaka Prefecture University in Sakai City, Japan from 1996 to 1997. Concentrations of ammonium and nitrite ions in dew were very high related to those in rain, and pHs of dew were relatively high, pH ca. 6.5. The authors found that when dew was dried, most nitrite and ammonium ions included in dew were decomposed. It is well-known that concentrated ammonium nitrite aqueous solution is unstable and decomposes to N{sub 2} and H{sub 2}O. During the drying process of dew, nitrite and ammonium would be concentrated and react to form N{sub 2}, and as a result, nitrite and ammonia in the dried dew are lost, that is, natural denitrification occurs in the drying process of dew. The authors report here results of the natural denitrification.

  14. Dry season streamflow persistence in seasonal climates

    NASA Astrophysics Data System (ADS)

    Dralle, David N.; Karst, Nathaniel J.; Thompson, Sally E.

    2016-01-01

    Seasonally dry ecosystems exhibit periods of high water availability followed by extended intervals during which rainfall is negligible and streamflows decline. Eventually, such declining flows will fall below the minimum values required to support ecosystem functions or services. The time at which dry season flows drop below these minimum values (Q*), relative to the start of the dry season, is termed the "persistence time" (). The persistence time determines how long seasonal streams can support various human or ecological functions during the dry season. In this study, we extended recent work in the stochastic hydrology of seasonally dry climates to develop an analytical model for the probability distribution function (PDF) of the persistence time. The proposed model accurately captures the mean of the persistence time distribution, but underestimates its variance. We demonstrate that this underestimation arises in part due to correlation between the parameters used to describe the dry season recession, but that this correlation can be removed by rescaling the flow variables. The mean persistence time predictions form one example of the broader class of streamflow statistics known as crossing properties, which could feasibly be combined with simple ecological models to form a basis for rapid risk assessment under different climate or management scenarios.

  15. Sex hormones and the dry eye.

    PubMed

    Truong, Susan; Cole, Nerida; Stapleton, Fiona; Golebiowski, Blanka

    2014-07-01

    The greater prevalence of dry eye in women compared to men suggests that sex hormones may have a role in this condition. This review aims to present evidence for how sex hormones may affect the ocular structures involved in the production, regulation and maintenance of the normal tear film. It is hypothesised that hormone changes alter the homeostasis of the ocular surface and contribute to dry eye. Androgens impact on the structure and function of the meibomian and lacrimal glands and therefore androgen deficiency is, at least in part, associated with the aetiology of dry eye. In contrast, reports of the effects of oestrogen and progesterone on these ocular structures and on the conjunctiva are contradictory and the mechanisms of action of these female-specific sex hormones in the eye are not well understood. The uncertainty of the effects of oestrogen and progesterone on dry eye symptoms is reflected in the controversial relationship between hormone replacement therapy and the signs and symptoms of dry eye. Current understanding of sex hormone influences on the immune system suggests that oestrogen may modulate a cascade of inflammatory events, which underlie dry eye.

  16. Drying a tuberculosis vaccine without freezing.

    PubMed

    Wong, Yun-Ling; Sampson, Samantha; Germishuizen, Willem Andreas; Goonesekera, Sunali; Caponetti, Giovanni; Sadoff, Jerry; Bloom, Barry R; Edwards, David

    2007-02-20

    With the increasing incidence of tuberculosis and drug resistant disease in developing countries due to HIV/AIDS, there is a need for vaccines that are more effective than the present bacillus Calmette-Guérin (BCG) vaccine. We demonstrate that BCG vaccine can be dried without traditional freezing and maintained with remarkable refrigerated and room-temperature stability for months through spray drying. Studies with a model Mycobacterium (Mycobacterium smegmatis) revealed that by removing salts and cryoprotectant (e.g., glycerol) from bacterial suspensions, the significant osmotic pressures that are normally produced on bacterial membranes through droplet drying can be reduced sufficiently to minimize loss of viability on drying by up to 2 orders of magnitude. By placing the bacteria in a matrix of leucine, high-yield, free-flowing, "vial-fillable" powders of bacteria (including M. smegmatis and M. bovis BCG) can be produced. These powders show relatively minor losses of activity after maintenance at 4 degrees C and 25 degrees C up to and beyond 4 months. Comparisons with lyophilized material prepared both with the same formulation and with a commercial formulation reveal that the spray-dried BCG has better overall viability on drying.

  17. Steam atmosphere drying exhaust steam recompression system

    DOEpatents

    Becker, F.E.; Smolensky, L.A.; Doyle, E.F.; DiBella, F.A.

    1994-03-08

    This invention relates to a heated steam atmosphere drying system comprising dryer in combination with an exhaust recompression system which is extremely energy efficient and eliminates dangers known to air dryers. The system uses superheated steam as the drying medium, which recirculates through the system where its heat of evaporation and heat of compression is recovered, thereby providing a constant source of heat to the drying chamber. The dryer has inlets whereby feedstock and superheated steam are fed therein. High heat transfer and drying rates are achieved by intimate contact of the superheated steam with the particles being dried. The dryer comprises a vessel which enables the feedstock and steam to enter and recirculate together. When the feedstock becomes dry it will exit the dryer with the steam and become separated from the steam through the use of a curvilinear louver separator (CLS). The CLS enables removal of fine and ultrafine particles from the dryer. Water vapor separated from the particles in the CLS as superheated steam, may then be recovered and recirculated as steam through the use of a compressor to either directly or indirectly heat the dryer, and a heat exchanger or a heater to directly provide heat to the dryer. This system not only provides a very efficient heat transfer system but results in a minimum carry-over of ultrafine particles thereby eliminating any explosive hazard. 17 figures.

  18. Steam atmosphere drying exhaust steam recompression system

    DOEpatents

    Becker, Frederick E.; Smolensky, Leo A.; Doyle, Edward F.; DiBella, Francis A.

    1994-01-01

    This invention relates to a heated steam atmosphere drying system comprising dryer in combination with an exhaust recompression system which is extremely energy efficient and eliminates dangers known to air dryers. The system uses superheated steam as the drying medium, which recirculated through the system where its heat of evaporation and heat of compression is recovered, thereby providing a constant source of heat to the drying chamber. The dryer has inlets whereby feedstock and superheated steam are fed therein. High heat transfer and drying rates are achieved by intimate contact of the superheated steam with the particles being dried The dryer comprises a vessel which enables the feedstock and steam to enter recirculate together. When the feedstock becomes dry it will exit the dryer with the steam and become separated from the steam through the use of a curvilinear louver separator (CLS). The CLS enables removal of fine and ultrafine particles from the dryer. Water vapor separated from the particles in the CLS as superheated steam, may then be recovered and recirculated as steam through the use of a compressor to either directly or indirectly heat the dryer, and a heat exchanger or a heater to directly provide heat to the dryer. This system not only provides a very efficient heat transfer system but results in a minimum carry-over of ultrafine particles thereby eliminating any explosive hazard.

  19. Is Biology Boring? Student Attitudes toward Biology

    ERIC Educational Resources Information Center

    Prokop, Pavol; Prokop, Matel; Tunnicliffe, Sue Dale

    2007-01-01

    The study examines the interests and attitudes of school students toward biology: through their interest in out-of-school activities and their attitude towards lessons as measured by interest, importance and difficulty. Biology lessons were relatively popular with the greatest preference found among students learning zoology. Girls showed…

  20. Evaluating the biogas potential of the dry fraction from pretreatment of food waste from households

    SciTech Connect

    Murto, Marika; Björnsson, Lovisa; Rosqvist, Håkan; Bohn, Irene

    2013-05-15

    Highlights: ► A novel approach for biogas production from a waste fraction that today is incinerated. ► Biogas production is possible in spite of the impurities of the waste. ► Tracer studies are applied in a novel way. ► Structural material is needed to improve the flow pattern of the waste. ► We provide a solution to biological treatment for the complex waste fraction. - Abstract: At the waste handling company NSR, Helsingborg, Sweden, the food waste fraction of source separated municipal solid waste is pretreated to obtain a liquid fraction, which is used for biogas production, and a dry fraction, which is at present incinerated. This pretreatment and separation is performed to remove impurities, however also some of the organic material is removed. The possibility of realising the methane potential of the dry fraction through batch-wise dry anaerobic digestion was investigated. The anaerobic digestion technique used was a two-stage process consisting of a static leach bed reactor and a methane reactor. Treatment of the dry fraction alone and in a mixture with structural material was tested to investigate the effect on the porosity of the leach bed. A tracer experiment was carried out to investigate the liquid flow through the leach beds, and this method proved useful in demonstrating a more homogenous flow through the leach bed when structural material was added. Addition of structural material to the dry fraction was needed to achieve a functional digestion process. A methane yield of 98 m{sup 3}/ton was obtained from the dry fraction mixed with structural material after 76 days of digestion. This was in the same range as obtained in the laboratory scale biochemical methane potential test, showing that it was possible to extract the organic content in the dry fraction in this type of dry digestion system for the production of methane.