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Sample records for gecko attachment system

  1. The adhesion model considering capillarity for gecko attachment system.

    PubMed

    Kim, Tae Wan; Bhushan, Bharat

    2008-03-01

    Geckos make use of approximately a million microscale hairs (setae) that branch off into hundreds of nanoscale spatulae to cling to different smooth and rough surfaces and detach at will. This hierarchical surface construction gives the gecko the adaptability to create a large real area of contact with surfaces. It is known that van der Waals force is the primary mechanism used to adhere to surfaces, and capillary force is a secondary effect that can further increase adhesive force. To investigate the effects of capillarity on gecko adhesion, we considered the capillary force as well as the solid-to-solid interaction. The capillary force expressed in terms of elliptical integral is calculated by numerical method to cope with surfaces with a wide range of contact angles. The adhesion forces exerted by a single gecko spatula in contact with planes with different contact angles for various relative humidities are calculated, and the contributions of capillary force to total adhesion force are evaluated. The simulation results are compared with experimental data. Finally, using the three-level hierarchical model recently developed to simulate a gecko seta contacting with random rough surface, the effect of the relative humidity and the hydrophobicity of surface on the gecko adhesion is investigated. PMID:17594962

  2. Adhesion and friction in gecko toe attachment and detachment.

    PubMed

    Tian, Yu; Pesika, Noshir; Zeng, Hongbo; Rosenberg, Kenny; Zhao, Boxin; McGuiggan, Patricia; Autumn, Kellar; Israelachvili, Jacob

    2006-12-19

    Geckos can run rapidly on walls and ceilings, requiring high friction forces (on walls) and adhesion forces (on ceilings), with typical step intervals of approximately 20 ms. The rapid switching between gecko foot attachment and detachment is analyzed theoretically based on a tape model that incorporates the adhesion and friction forces originating from the van der Waals forces between the submicron-sized spatulae and the substrate, which are controlled by the (macroscopic) actions of the gecko toes. The pulling force of a spatula along its shaft with an angle between theta 0 and 90 degrees to the substrate, has a "normal adhesion force" contribution, produced at the spatula-substrate bifurcation zone, and a "lateral friction force" contribution from the part of spatula still in contact with the substrate. High net friction and adhesion forces on the whole gecko are obtained by rolling down and gripping the toes inward to realize small pulling angles between the large number of spatulae in contact with the substrate. To detach, the high adhesion/friction is rapidly reduced to a very low value by rolling the toes upward and backward, which, mediated by the lever function of the setal shaft, peels the spatulae off perpendicularly from the substrates. By these mechanisms, both the adhesion and friction forces of geckos can be changed over three orders of magnitude, allowing for the swift attachment and detachment during gecko motion. The results have obvious implications for the fabrication of dry adhesives and robotic systems inspired by the gecko's locomotion mechanism. PMID:17148600

  3. Biomimetic wall-shaped hierarchical microstructure for gecko-like attachment.

    PubMed

    Kasem, Haytam; Tsipenyuk, Alexey; Varenberg, Michael

    2015-04-21

    Most biological hairy adhesive systems involved in locomotion rely on spatula-shaped terminal elements, whose operation has been actively studied during the last decade. However, though functional principles underlying their amazing performance are now well understood, due to technical difficulties in manufacturing the complex structure of hierarchical spatulate systems, a biomimetic surface structure featuring true shear-induced dynamic attachment still remains elusive. To try bridging this gap, a novel method of manufacturing gecko-like attachment surfaces is devised based on a laser-micromachining technology. This method overcomes the inherent disadvantages of photolithography techniques and opens wide perspectives for future production of gecko-like attachment systems. Advanced smart-performance surfaces featuring thin-film-based hierarchical shear-activated elements are fabricated and found capable of generating friction force of several tens of times the contact load, which makes a significant step forward towards a true gecko-like adhesive. PMID:25693519

  4. 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. PMID:22572030

  5. 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

  6. Design and fabrication of polymer based dry adhesives inspired by the gecko adhesive system

    NASA Astrophysics Data System (ADS)

    Jin, Kejia

    There has been significant interest in developing dry adhesives mimicking the gecko adhesive system, which offers several advantages compared to conventional pressure sensitive adhesives. Specifically, gecko adhesive pads have anisotropic adhesion properties: the adhesive pads (spatulae) stick strongly when sheared in one direction but are non-adherent when sheared in the opposite direction. This anisotropy property is attributed to the complex topography of the array of fine tilted and curved columnar structures (setae) that bear the spatulae. In this thesis, easy, scalable methods, relying on conventional and unconventional techniques are presented to incorporate tilt in the fabrication of synthetic polymer-based dry adhesives mimicking the gecko adhesive system, which provide anisotropic adhesion properties. In the first part of the study, the anisotropic adhesion and friction properties of samples with various tilt angles to test the validity of a nanoscale tape-peeling model of spatular function are measured. Consistent with the Peel Zone model, samples with lower tilt angles yielded larger adhesion forces. Contact mechanics of the synthetic array were highly anisotropic, consistent with the frictional adhesion model and gecko-like. Based on the original design, a new design of gecko-like dry adhesives was developed which showed superior tribological properties and furthermore showed anisotropic adhesive properties without the need for tilt in the structures. These adhesives can be used to reversibly suspend weights from vertical surfaces (e.g., walls) and, for the first time to our knowledge, horizontal surfaces (e.g., ceilings) by simultaneously and judiciously activating anisotropic friction and adhesion forces. Furthermore, adhesion properties between artificial gecko-inspired dry adhesives and rough substrates with varying roughness are studied. The results suggest that both adhesion and friction forces on a rough substrate depends significantly on the

  7. Passively stuck: death does not affect gecko adhesion strength.

    PubMed

    Stewart, William J; Higham, Timothy E

    2014-12-01

    Many geckos use adhesive toe pads on the bottom of their digits to attach to surfaces with remarkable strength. Although gecko adhesion has been studied for hundreds of years, gaps exist in our understanding at the whole-animal level. It remains unclear whether the strength and maintenance of adhesion are determined by the animal or are passively intrinsic to the system. Here we show, for the first time, that strong adhesion is produced passively at the whole-animal level. Experiments on both live and recently euthanized tokay geckos (Gekko gecko) revealed that death does not affect the dynamic adhesive force or motion of a gecko foot when pulled along a vertical surface. Using a novel device that applied repeatable and steady-increasing pulling forces to the foot in shear, we found that the adhesive force was similarly high and variable when the animal was alive (mean ± s.d. = 5.4 ± 1.7 N) and within 30 min after death (5.4 ± 2.1 N). However, kinematic analyses showed that live geckos are able to control the degree of toe pad engagement and can rapidly stop strong adhesion by hyperextending the toes. This study offers the first assessment of whole-animal adhesive force under extremely controlled conditions. Our findings reveal that dead geckos maintain the ability to adhere with the same force as living animals, disproving that strong adhesion requires active control. PMID:25472940

  8. Ceramic blade attachment system

    DOEpatents

    Boyd, Gary L.

    1994-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a pair of recessed portions thereon. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings have a pair of grooves therein in which are positioned a pair of pins having a generally rectangular cross-section and a reaction surface thereon. A pair of cylindrical rollers interposed respective ones of the pair of reaction surfaces and the pair of recessed portions. The attachment system or turbine assembly provides an economical, reliable and effective attachment of a component having a preestablished rate of thermal expansion to a component having a greater preestablished rate of thermal expansion.

  9. Ceramic blade attachment system

    DOEpatents

    Boyd, G.L.

    1994-12-13

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a pair of recessed portions thereon. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings have a pair of grooves therein in which are positioned a pair of pins having a generally rectangular cross-section and a reaction surface thereon. A pair of cylindrical rollers interposed respective ones of the pair of reaction surfaces and the pair of recessed portions. The attachment system or turbine assembly provides an economical, reliable and effective attachment of a component having a preestablished rate of thermal expansion to a component having a greater preestablished rate of thermal expansion. 3 figures.

  10. Mechanical analyses on the digital behaviour of the Tokay gecko (Gekko gecko) based on a multi-level directional adhesion model

    PubMed Central

    Wu, Xuan; Wang, Xiaojie; Mei, Tao; Sun, Shaoming

    2015-01-01

    This paper proposes a multi-level hierarchical model for the Tokay gecko (Gekko gecko) adhesive system and analyses the digital behaviour of the G. gecko under macro/meso-level scale. The model describes the structures of G. gecko's adhesive system from the nano-level spatulae to the sub-millimetre-level lamella. The G. gecko's seta is modelled using inextensible fibril based on Euler's elastica theorem. Considering the side contact of the spatular pads of the seta on the flat and rigid substrate, the directional adhesion behaviour of the seta has been investigated. The lamella-induced attachment and detachment have been modelled to simulate the active digital hyperextension (DH) and the digital gripping (DG) phenomena. The results suggest that a tiny angular displacement within 0.25° of the lamellar proximal end is necessary in which a fast transition from attachment to detachment or vice versa is induced. The active DH helps release the torque to induce setal non-sliding detachment, while the DG helps apply torque to make the setal adhesion stable. The lamella plays a key role in saving energy during detachment to adapt to its habitat and provides another adhesive function which differs from the friction-dependent setal adhesion system controlled by the dynamic of G. gecko's body. PMID:26345081

  11. Belt attachment and system

    DOEpatents

    Schneider, Abraham D.; Davidson, Erick M.

    2016-02-02

    Disclosed herein is a belt assembly including a flexible belt with an improved belt attachment. The belt attachment includes two crossbars spaced along the length of the belt. The crossbars retain bearings that allow predetermined movement in six degrees of freedom. The crossbars are connected by a rigid body that attaches to the bearings. Implements that are attached to the rigid body are simply supported but restrained in pitching rotation.

  12. A microfabricated gecko-inspired controllable and reusable dry adhesive

    NASA Astrophysics Data System (ADS)

    Chary, Sathya; Tamelier, John; Turner, Kimberly

    2013-02-01

    Geckos utilize a robust reversible adhesive to repeatedly attach and detach from a variety of vertical and inverted surfaces, using structurally anisotropic micro- and nano-scale fibrillar structures. These fibers, when suitably articulated, are able to control the real area of contact and thereby generate high-to-low van der Waals forces. Key characteristics of the natural system include highly anisotropic adhesion and shear forces for controllable attachment, a high adhesion to initial preload force ratio (μ‧) of 8-16, lack of inter-fiber self-adhesion, and operation over more than 30 000 cycles without loss of adhesion performance. A highly reusable synthetic adhesive has been developed using tilted polydimethylsiloxane (PDMS) half-cylinder micron-scale fibers, retaining up to 77% of the initial value over 10 000 repeated test cycles against a flat glass puck. In comparison with other gecko-inspired adhesives tested over 10 000 cycles or more thus far, this paper reports the highest value of μ‧, along with a large shear force of ˜78 kPa, approaching the 88-226 kPa range of gecko toes. The anisotropic adhesion forces are close to theoretical estimates from the Kendall peel model, quantitatively showing how lateral shearing articulation in a manner similar to the gecko may be used to obtain adhesion anisotropy with synthetic fibers using a combination of tilt angle and anisotropic fiber geometry.

  13. Turbine nozzle attachment system

    DOEpatents

    Norton, Paul F.; Shaffer, James E.

    1995-01-01

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The nozzle guide vane assembly includes a pair of legs extending radially outwardly from an outer shroud and a pair of mounting legs extending radially inwardly from an inner shroud. Each of the pair of legs and mounting legs have a pair of holes therein. A plurality of members attached to the gas turbine engine have a plurality of bores therein which axially align with corresponding ones of the pair of holes in the legs. A plurality of pins are positioned within the corresponding holes and bores radially positioning the nozzle guide vane assembly about a central axis of the gas turbine engine.

  14. Turbine nozzle attachment system

    DOEpatents

    Norton, P.F.; Shaffer, J.E.

    1995-10-24

    A nozzle guide vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and is attached to conventional metallic components. The nozzle guide vane assembly includes a pair of legs extending radially outwardly from an outer shroud and a pair of mounting legs extending radially inwardly from an inner shroud. Each of the pair of legs and mounting legs have a pair of holes therein. A plurality of members attached to the gas turbine engine have a plurality of bores therein which axially align with corresponding ones of the pair of holes in the legs. A plurality of pins are positioned within the corresponding holes and bores radially positioning the nozzle guide vane assembly about a central axis of the gas turbine engine. 3 figs.

  15. Ceramic blade attachment system

    DOEpatents

    Frey, G.A.; Jimenez, O.D.

    1996-12-03

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine flange having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine flange includes a first upstanding flange and a second upstanding flange having a groove formed between them. The turbine flange further includes a recess. Each of the first and second upstanding flanges have a plurality of bores therein. A turbine blade has a first member and a second member positioned in one of the groove and the recess. Each of the first member and the second member have a plurality of bores therein. A pin is positioned in respective ones of the plurality of bores in the first and second upstanding members and the first and second members and attach the blade to the turbine flange. The pin has a preestablished rate of thermal expansion being substantially equal to the rate of thermal expansion of the blade. 4 figs.

  16. Ceramic blade attachment system

    DOEpatents

    Frey, deceased, Gary A.; Jimenez, Oscar D.

    1996-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine flange having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine flange includes a first upstanding flange and a second upstanding flange having a groove formed therebetween. The turbine flange further includes a recess. Each of the first and second upstanding flanges have a plurality of bores therein. A turbine blade has a first member and a second member positioned in one of the groove and the recess. Each of the first member and the second member have a plurality of bores therein. And, a pin is positioned in respective ones of the plurality of bores in the first and second upstanding members and the first and second members and attach the blade to the turbine flange. The pin has a preestablished rate of thermal expansion being substantially equal to the rate of thermal expansion of the blade.

  17. Effect of stiffness of multi-level hierarchical attachment system on adhesion enhancement.

    PubMed

    Kim, Tae Wan; Bhushan, Bharat

    2007-10-01

    Geckos are known for their remarkable ability to cling on and detach from ceilings and walls using a unique attachment system. Their foot pads are covered by a large number of small hair (setae) that contain many branches per seta with a lower level of spatulae. This hierarchical structure gives the gecko adaptability to create a large real area of contact with rough surfaces. In this study, using the three-level hierarchical model recently developed to simulate a gecko seta contacting with random rough surface, the effects of spring stiffness and number of springs on the adhesion enhancement of multi-level hierarchical model are investigated. One- and three-level hierarchically structured spring models with different spring stiffnesses and number of springs on each level in contact with various rough surfaces are considered. The efficiency of attachment-the adhesion coefficient, the adhesion force, the number of contacts and the adhesion energy-for the three-level models with different stiffness is investigated in contact with different rough surfaces. PMID:17555877

  18. Ceramic blade attachment system

    DOEpatents

    Shaffer, James E.

    1995-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a first groove and a second groove therein. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings has a first groove and a second groove therein. The space or void formed between the first grooves and the second grooves has a plurality of spherical balls positioned therein. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade.

  19. Ceramic blade attachment system

    DOEpatents

    Shaffer, James E.

    1995-01-01

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine disc having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade and forms a turbine assembly. The turbine blade has a root portion defining a pair of sides having a pair of grooves therein. The turbine assembly includes a pair of flanges between which the turbine blades are positioned. Each of the pair of flanges has a plurality of grooves defined therein. The grooves within the pair of flanges are aligned with the grooves in the blades and have a space formed therebetween. A plurality of spherical balls are positioned within the space. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade.

  20. Ceramic blade attachment system

    DOEpatents

    Shaffer, J.E.

    1995-07-11

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine disc having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade and forms a turbine assembly. The turbine blade has a root portion defining a pair of sides having a pair of grooves therein. The turbine assembly includes a pair of flanges between which the turbine blades are positioned. Each of the pair of flanges has a plurality of grooves defined therein. The grooves within the pair of flanges are aligned with the grooves in the blades and have a space formed therebetween. A plurality of spherical balls are positioned within the space. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade. 4 figs.

  1. Ceramic blade attachment system

    DOEpatents

    Shaffer, J.E.

    1995-01-10

    A turbine blade having a preestablished rate of thermal expansion is attached to a turbine wheel having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine blade. The turbine blade has a root portion having a first groove and a second groove therein. The turbine wheel includes a plurality of openings in which the turbine blade is positioned. Each of the openings has a first groove and a second groove therein. The space or void formed between the first grooves and the second grooves has a plurality of spherical balls positioned therein. The plurality of spherical balls has a preestablished rate of thermal expansion being equal to the preestablished rate of thermal expansion of the turbine blade. 4 figures.

  2. The effect of temperature and humidity on adhesion of a gecko-inspired adhesive: implications for the natural system.

    PubMed

    Stark, Alyssa Y; Klittich, Mena R; Sitti, Metin; Niewiarowski, Peter H; Dhinojwala, Ali

    2016-01-01

    The adhesive system of geckos has inspired hundreds of synthetic adhesives. While this system has been used relentlessly as a source of inspiration, less work has been done in reverse, where synthetics are used to test questions and hypotheses about the natural system. Here we take such an approach. We tested shear adhesion of a mushroom-tipped synthetic gecko adhesive under conditions that produced perplexing results in the natural adhesive system. Synthetic samples were tested at two temperatures (12 °C and 32 °C) and four different humidity levels (30%, 55%, 70%, and 80% RH). Surprisingly, adhesive performance of the synthetic samples matched that of living geckos, suggesting that uncontrolled parameters in the natural system, such as surface chemistry and material changes, may not be as influential in whole-animal performance as previously thought. There was one difference, however, when comparing natural and synthetic adhesive performance. At 12 °C and 80% RH, adhesion of the synthetic structures was lower than expected based on the natural system's performance. Our approach highlights a unique opportunity for both biologists and material scientists, where new questions and hypotheses can be fueled by joint comparisons of the natural and synthetic systems, ultimately improving knowledge of both. PMID:27480603

  3. A new angle on clinging in geckos: incline, not substrate, triggers the deployment of the adhesive system.

    PubMed

    Russell, Anthony P; Higham, Timothy E

    2009-10-22

    Lizards commonly climb in complex three-dimensional habitats, and gekkotans are particularly adept at doing this by using an intricate adhesive system involving setae on the ventral surface of their digits. However, it is not clear whether geckos always deploy their adhesive system, given that doing so may result in decreased (i.e. reduction in speed) locomotor performance. Here, we investigate circumstances under which the adhesive apparatus of clinging geckos becomes operative, and examine the potential trade-offs between speed and clinging. We quantify locomotor kinematics of a gecko with adhesive capabilities (Tarentola mauritanica) and one without (Eublepharis macularius). Whereas, somewhat unusually, E. macularius did not suffer a decrease in locomotor performance with an increase in incline, T. mauritanica exhibited a significant decrease in speed between the level and a 10 degrees incline. We demonstrate that this results from the combined influence of slope and the deployment of the adhesive system. All individuals kept their digits hyperextended on the level, but three of the six individuals deployed their adhesive system on the 10 degrees incline, and they exhibited the greatest decrease in velocity. The deployment of the adhesive system was dependent on incline, not surface texture (600 grit sandpaper and Plexiglas), despite slippage occurring on the level Plexiglas substrate. Our results highlight the type of sensory feedback (gravity) necessary for deployment of the adhesive system, and the trade-offs associated with adhesion. PMID:19656797

  4. The effect of temperature and humidity on adhesion of a gecko-inspired adhesive: implications for the natural system

    PubMed Central

    Stark, Alyssa Y.; Klittich, Mena R.; Sitti, Metin; Niewiarowski, Peter H.; Dhinojwala, Ali

    2016-01-01

    The adhesive system of geckos has inspired hundreds of synthetic adhesives. While this system has been used relentlessly as a source of inspiration, less work has been done in reverse, where synthetics are used to test questions and hypotheses about the natural system. Here we take such an approach. We tested shear adhesion of a mushroom-tipped synthetic gecko adhesive under conditions that produced perplexing results in the natural adhesive system. Synthetic samples were tested at two temperatures (12 °C and 32 °C) and four different humidity levels (30%, 55%, 70%, and 80% RH). Surprisingly, adhesive performance of the synthetic samples matched that of living geckos, suggesting that uncontrolled parameters in the natural system, such as surface chemistry and material changes, may not be as influential in whole-animal performance as previously thought. There was one difference, however, when comparing natural and synthetic adhesive performance. At 12 °C and 80% RH, adhesion of the synthetic structures was lower than expected based on the natural system’s performance. Our approach highlights a unique opportunity for both biologists and material scientists, where new questions and hypotheses can be fueled by joint comparisons of the natural and synthetic systems, ultimately improving knowledge of both. PMID:27480603

  5. Does the mechanism of sex determination constrain the potential for sex manipulation? A test in geckos with contrasting sex-determining systems.

    PubMed

    Kratochvíl, Lukás; Kubicka, Lukás; Landová, Eva

    2008-03-01

    The concentration of yolk steroids was suggested to influence offspring gender in oviparous animals subject to both temperature-dependent sex determination (TSD) and genotypic sex determination (GSD). However, the proposed mechanisms of steroid effects are thought to differ between TSD and GSD: a direct effect of oestrogens on gonad feminisation in TSD species vs a differential induction of male-producing or female-producing gametes in GSD species. Geckos offer an ideal opportunity for testing these suggested mechanisms. Closely related gecko species differ in their modes of sex determination. They lay clutches of two synchronously formed eggs; both eggs share equal steroid levels. If identical hormonal composition and environment during vitellogenesis, gravidity and incubation determine the sex of the progeny, siblings should share the same gender in both TSD and GSD geckos. We found strong support for this prediction in a TSD gecko species. Among clutches that were incubated at the temperature that produced both sexes, there were no clutches with siblings of the opposite sex. On the other hand, about half of the clutches yielded siblings of the opposite sex in four GSD species. These results suggest that sex-determining systems constrain the ability of the female to produce single-sex siblings and, hence, it seems that the GSD mechanism constrains the opportunities for sex ratio manipulation in geckos via yolk steroid manipulation. PMID:17994209

  6. Does the mechanism of sex determination constrain the potential for sex manipulation? A test in geckos with contrasting sex-determining systems

    NASA Astrophysics Data System (ADS)

    Kratochvíl, Lukáš; Kubička, Lukáš; Landová, Eva

    2008-03-01

    The concentration of yolk steroids was suggested to influence offspring gender in oviparous animals subject to both temperature-dependent sex determination (TSD) and genotypic sex determination (GSD). However, the proposed mechanisms of steroid effects are thought to differ between TSD and GSD: a direct effect of oestrogens on gonad feminisation in TSD species vs a differential induction of male-producing or female-producing gametes in GSD species. Geckos offer an ideal opportunity for testing these suggested mechanisms. Closely related gecko species differ in their modes of sex determination. They lay clutches of two synchronously formed eggs; both eggs share equal steroid levels. If identical hormonal composition and environment during vitellogenesis, gravidity and incubation determine the sex of the progeny, siblings should share the same gender in both TSD and GSD geckos. We found strong support for this prediction in a TSD gecko species. Among clutches that were incubated at the temperature that produced both sexes, there were no clutches with siblings of the opposite sex. On the other hand, about half of the clutches yielded siblings of the opposite sex in four GSD species. These results suggest that sex-determining systems constrain the ability of the female to produce single-sex siblings and, hence, it seems that the GSD mechanism constrains the opportunities for sex ratio manipulation in geckos via yolk steroid manipulation.

  7. Dynamic self-cleaning in gecko setae via digital hyperextension.

    PubMed

    Hu, Shihao; Lopez, Stephanie; Niewiarowski, Peter H; Xia, Zhenhai

    2012-11-01

    Gecko toe pads show strong adhesion on various surfaces yet remain remarkably clean around everyday contaminants. An understanding of how geckos clean their toe pads while being in motion is essential for the elucidation of animal behaviours as well as the design of biomimetic devices with optimal performance. Here, we test the self-cleaning of geckos during locomotion. We provide, to our knowledge, the first evidence that geckos clean their feet through a unique dynamic self-cleaning mechanism via digital hyperextension. When walking naturally with hyperextension, geckos shed dirt from their toes twice as fast as they would if walking without hyperextension, returning their feet to nearly 80 per cent of their original stickiness in only four steps. Our dynamic model predicts that when setae suddenly release from the attached substrate, they generate enough inertial force to dislodge dirt particles from the attached spatulae. The predicted cleaning force on dirt particles significantly increases when the dynamic effect is included. The extraordinary design of gecko toe pads perfectly combines dynamic self-cleaning with repeated attachment/detachment, making gecko feet sticky yet clean. This work thus provides a new mechanism to be considered for biomimetic design of highly reuseable and reliable dry adhesives and devices. PMID:22696482

  8. Microfabricated adhesive mimicking gecko foot-hair

    NASA Astrophysics Data System (ADS)

    Geim, A. K.; Dubonos, S. V.; Grigorieva, I. V.; Novoselov, K. S.; Zhukov, A. A.; Shapoval, S. Yu.

    2003-07-01

    The amazing climbing ability of geckos has attracted the interest of philosophers and scientists alike for centuries. However, only in the past few years has progress been made in understanding the mechanism behind this ability, which relies on submicrometre keratin hairs covering the soles of geckos. Each hair produces a miniscule force ~10-7 N (due to van der Waals and/or capillary interactions) but millions of hairs acting together create a formidable adhesion of ~10 N cm-2: sufficient to keep geckos firmly on their feet, even when upside down on a glass ceiling. It is very tempting to create a new type of adhesive by mimicking the gecko mechanism. Here we report on a prototype of such 'gecko tape' made by microfabrication of dense arrays of flexible plastic pillars, the geometry of which is optimized to ensure their collective adhesion. Our approach shows a way to manufacture self-cleaning, re-attachable dry adhesives, although problems related to their durability and mass production are yet to be resolved.

  9. How Do Geckos Stick?

    ERIC Educational Resources Information Center

    Short, Harold; Lundsgaard, Morten F. V.; Krajcik, Joseph S.

    2008-01-01

    Understanding how geckos--small lizards belonging to the family "Gekkonindae"--can "defy gravity" and walk across a ceiling provides a fascinating frame through which students can not only learn valuable content about electrostatic forces, but also engage in authentic scientific practice and explore new technologies based on gecko adhesion. In…

  10. Anti-tumor effect and influence of Gekko gecko Linnaeus on the immune system of sarcoma 180-bearing mice.

    PubMed

    You, Qi; Han, Shiyu; Zhang, Yuanlong; Zheng, Jianhua

    2009-01-01

    Gekko gecko Linnaeus (GgL) is an extract used in traditional Chinese medicine. In the present study, we examined the anti-tumor activity of GgL and its effect on the immune system of mice. Sarcoma 180-bearing mice were used as the animal model, and cisplatin was applied as the positive control drug. The mice were randomly divided into six groups, and each group was treated with a different drug or drug concentration. The effects of GgL were evaluated based on its anti-tumor activity and prolongation of the lifespan, the lymphocyte transformation rate and pathological changes observed in the tumors. The results suggest that GgL has anti-tumor activities and up-regulates the immune system in a dose-dependent manner. This study provides original data related to the anti-tumor and immune up-regulating function of GgL. PMID:21475868

  11. Stick-slip friction of gecko-mimetic flaps on smooth and rough surfaces.

    PubMed

    Das, Saurabh; Cadirov, Nicholas; Chary, Sathya; Kaufman, Yair; Hogan, Jack; Turner, Kimberly L; Israelachvili, Jacob N

    2015-03-01

    The discovery and understanding of gecko 'frictional-adhesion' adhering and climbing mechanism has allowed researchers to mimic and create gecko-inspired adhesives. A few experimental and theoretical approaches have been taken to understand the effect of surface roughness on synthetic adhesive performance, and the implications of stick-slip friction during shearing. This work extends previous studies by using a modified surface forces apparatus to quantitatively measure and model frictional forces between arrays of polydimethylsiloxane gecko footpad-mimetic tilted microflaps against smooth and rough glass surfaces. Constant attachments and detachments occur between the surfaces during shearing, as described by an avalanche model. These detachments ultimately result in failure of the adhesion interface and have been characterized in this study. Stick-slip friction disappears with increasing velocity when the flaps are sheared against a smooth silica surface; however, stick-slip was always present at all velocities and loads tested when shearing the flaps against rough glass surfaces. These results demonstrate the significance of pre-load, shearing velocity, shearing distances, commensurability and shearing direction of gecko-mimetic adhesives and provide us a simple model for analysing and/or designing such systems. PMID:25589569

  12. Stick–slip friction of gecko-mimetic flaps on smooth and rough surfaces

    PubMed Central

    Das, Saurabh; Cadirov, Nicholas; Chary, Sathya; Kaufman, Yair; Hogan, Jack; Turner, Kimberly L.; Israelachvili, Jacob N.

    2015-01-01

    The discovery and understanding of gecko ‘frictional-adhesion’ adhering and climbing mechanism has allowed researchers to mimic and create gecko-inspired adhesives. A few experimental and theoretical approaches have been taken to understand the effect of surface roughness on synthetic adhesive performance, and the implications of stick–slip friction during shearing. This work extends previous studies by using a modified surface forces apparatus to quantitatively measure and model frictional forces between arrays of polydimethylsiloxane gecko footpad-mimetic tilted microflaps against smooth and rough glass surfaces. Constant attachments and detachments occur between the surfaces during shearing, as described by an avalanche model. These detachments ultimately result in failure of the adhesion interface and have been characterized in this study. Stick–slip friction disappears with increasing velocity when the flaps are sheared against a smooth silica surface; however, stick–slip was always present at all velocities and loads tested when shearing the flaps against rough glass surfaces. These results demonstrate the significance of pre-load, shearing velocity, shearing distances, commensurability and shearing direction of gecko-mimetic adhesives and provide us a simple model for analysing and/or designing such systems. PMID:25589569

  13. Human climbing with efficiently scaled gecko-inspired dry adhesives

    PubMed Central

    Hawkes, Elliot W.; Eason, Eric V.; Christensen, David L.; Cutkosky, Mark R.

    2015-01-01

    Since the discovery of the mechanism of adhesion in geckos, many synthetic dry adhesives have been developed with desirable gecko-like properties such as reusability, directionality, self-cleaning ability, rough surface adhesion and high adhesive stress. However, fully exploiting these adhesives in practical applications at different length scales requires efficient scaling (i.e. with little loss in adhesion as area grows). Just as natural gecko adhesives have been used as a benchmark for synthetic materials, so can gecko adhesion systems provide a baseline for scaling efficiency. In the tokay gecko (Gekko gecko), a scaling power law has been reported relating the maximum shear stress σmax to the area A: σmax ∝ A−1/4. We present a mechanical concept which improves upon the gecko's non-uniform load-sharing and results in a nearly even load distribution over multiple patches of gecko-inspired adhesive. We created a synthetic adhesion system incorporating this concept which shows efficient scaling across four orders of magnitude of area, yielding an improved scaling power law: σmax ∝ A−1/50. Furthermore, we found that the synthetic adhesion system does not fail catastrophically when a simulated failure is induced on a portion of the adhesive. In a practical demonstration, the synthetic adhesion system enabled a 70 kg human to climb vertical glass with 140 cm2 of adhesive per hand. PMID:25411404

  14. Geckos as Springs: Mechanics Explain Across-Species Scaling of Adhesion

    PubMed Central

    Gilman, Casey A.; Imburgia, Michael J.; Bartlett, Michael D.; King, Daniel R.; Crosby, Alfred J.; Irschick, Duncan J.

    2015-01-01

    One of the central controversies regarding the evolution of adhesion concerns how adhesive force scales as animals change in size, either among or within species. A widely held view is that as animals become larger, the primary mechanism that enables them to climb is increasing pad area. However, prior studies show that much of the variation in maximum adhesive force remains unexplained, even when area is accounted for. We tested the hypothesis that maximum adhesive force among pad-bearing gecko species is not solely dictated by toepad area, but also depends on the ratio of toepad area to gecko adhesive system compliance in the loading direction, where compliance (C) is the change in extension (Δ) relative to a change in force (F) while loading a gecko’s adhesive system (C = dΔ/dF). Geckos are well-known for their ability to climb on a range of vertical and overhanging surfaces, and range in mass from several grams to over 300 grams, yet little is understood of the factors that enable adhesion to scale with body size. We examined the maximum adhesive force of six gecko species that vary in body size (~2–100 g). We also examined changes between juveniles and adults within a single species (Phelsuma grandis). We found that maximum adhesive force and toepad area increased with increasing gecko size, and that as gecko species become larger, their adhesive systems become significantly less compliant. Additionally, our hypothesis was supported, as the best predictor of maximum adhesive force was not toepad area or compliance alone, but the ratio of toepad area to compliance. We verified this result using a synthetic “model gecko” system comprised of synthetic adhesive pads attached to a glass substrate and a synthetic tendon (mechanical spring) of finite stiffness. Our data indicate that increases in toepad area as geckos become larger cannot fully account for increased adhesive abilities, and decreased compliance must be included to explain the scaling of

  15. Staying sticky: contact self-cleaning of gecko-inspired adhesives

    PubMed Central

    Mengüç, Yiğit; Röhrig, Michael; Abusomwan, Uyiosa; Hölscher, Hendrik; Sitti, Metin

    2014-01-01

    The exceptionally adhesive foot of the gecko remains clean in dirty environments by shedding contaminants with each step. Synthetic gecko-inspired adhesives have achieved similar attachment strengths to the gecko on smooth surfaces, but the process of contact self-cleaning has yet to be effectively demonstrated. Here, we present the first gecko-inspired adhesive that has matched both the attachment strength and the contact self-cleaning performance of the gecko's foot on a smooth surface. Contact self-cleaning experiments were performed with three different sizes of mushroom-shaped elastomer microfibres and five different sizes of spherical silica contaminants. Using a load–drag–unload dry contact cleaning process similar to the loads acting on the gecko foot during locomotion, our fully contaminated synthetic gecko adhesives could recover lost adhesion at a rate comparable to that of the gecko. We observed that the relative size of contaminants to the characteristic size of the microfibres in the synthetic adhesive strongly determined how and to what degree the adhesive recovered from contamination. Our approximate model and experimental results show that the dominant mechanism of contact self-cleaning is particle rolling during the drag process. Embedding of particles between adjacent fibres was observed for particles with diameter smaller than the fibre tips, and further studied as a temporary cleaning mechanism. By incorporating contact self-cleaning capabilities, real-world applications of synthetic gecko adhesives, such as reusable tapes, clothing closures and medical adhesives, would become feasible. PMID:24554579

  16. Nuclear reactor fuel rod attachment system

    DOEpatents

    Not Available

    1980-09-17

    A reusable system is described for removably attaching a nuclear reactor fuel rod to a support member. A locking cap is secured to the fuel rod and a locking strip is fastened to the support member. The locking cap has two opposing fingers shaped to form a socket having a body portion. The locking strip has an extension shaped to rigidly attach to the socket's body portion. The locking cap's fingers are resiliently deflectable. For attachment, the locking cap is longitudinally pushed onto the locking strip causing the extension to temporarily deflect open the fingers to engage the socket's body portion. For removal, the process is reversed.

  17. The effect of surface water and wetting on gecko adhesion.

    PubMed

    Stark, Alyssa Y; Sullivan, Timothy W; Niewiarowski, Peter H

    2012-09-01

    Despite profound interest in the mechanics and performance of the gecko adhesive system, relatively few studies have focused on performance under conditions that are ecologically relevant to the natural habitats of geckos. Because geckos are likely to encounter surfaces that are wet, we used shear force adhesion measurements to examine the effect of surface water and toe pad wetting on the whole-animal performance of a tropical-dwelling gecko (Gekko gecko). To test the effect of surface wetting, we measured the shear adhesive force of geckos on three substrate conditions: dry glass, glass misted with water droplets and glass fully submerged in water. We also investigated the effect of wetting on the adhesive toe pad by soaking the toe pads prior to testing. Finally, we tested for repeatability of the adhesive system in each wetting condition by measuring shear adhesion after each step a gecko made under treatment conditions. Wetted toe pads had significantly lower shear adhesive force in all treatments (0.86 ± 0.09 N) than the control (17.96 ± 3.42 N), as did full immersion in water (0.44 ± 0.03 N). Treatments with droplets of water distributed across the surface were more variable and did not differ from treatments where the surface was dry (4.72 ± 1.59 N misted glass; 9.76 ± 2.81 N dry glass), except after the gecko took multiple steps. These findings suggest that surface water and the wetting of a gecko's adhesive toe pads may have significant consequences for the ecology and behavior of geckos living in tropical environments. PMID:22875772

  18. Nuclear reactor fuel rod attachment system

    DOEpatents

    Christiansen, David W.

    1982-01-01

    A reusable system for removably attaching a nuclear reactor fuel rod (12) to a support member (14). A locking cap (22) is secured to the fuel rod (12) and a locking strip (24) is fastened to the support member (14). The locking cap (22) has two opposing fingers (24a and 24b) shaped to form a socket having a body portion (26). The locking strip has an extension (36) shaped to rigidly attach to the socket's body portion (26). The locking cap's fingers are resiliently deflectable. For attachment, the locking cap (22) is longitudinally pushed onto the locking strip (24) causing the extension (36) to temporarily deflect open the fingers (24a and 24b) to engage the socket's body portion (26). For removal, the process is reversed.

  19. Restriction Site-Associated DNA Sequencing (RAD-seq) Reveals an Extraordinary Number of Transitions among Gecko Sex-Determining Systems.

    PubMed

    Gamble, Tony; Coryell, Jessi; Ezaz, Tariq; Lynch, Joshua; Scantlebury, Daniel P; Zarkower, David

    2015-05-01

    Sex chromosomes have evolved many times in animals and studying these replicate evolutionary "experiments" can help broaden our understanding of the general forces driving the origin and evolution of sex chromosomes. However this plan of study has been hindered by the inability to identify the sex chromosome systems in the large number of species with cryptic, homomorphic sex chromosomes. Restriction site-associated DNA sequencing (RAD-seq) is a critical enabling technology that can identify the sex chromosome systems in many species where traditional cytogenetic methods have failed. Using newly generated RAD-seq data from 12 gecko species, along with data from the literature, we reinterpret the evolution of sex-determining systems in lizards and snakes and test the hypothesis that sex chromosomes can routinely act as evolutionary traps. We uncovered between 17 and 25 transitions among gecko sex-determining systems. This is approximately one-half to two-thirds of the total number of transitions observed among all lizards and snakes. We find support for the hypothesis that sex chromosome systems can readily become trap-like and show that adding even a small number of species from understudied clades can greatly enhance hypothesis testing in a model-based phylogenetic framework. RAD-seq will undoubtedly prove useful in evaluating other species for male or female heterogamety, particularly the majority of fish, amphibian, and reptile species that lack visibly heteromorphic sex chromosomes, and will significantly accelerate the pace of biological discovery. PMID:25657328

  20. Efficient active actuation to imitate locomotion of gecko's toes using an ionic polymer-metal composite actuator enhanced by carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yu, Min; He, Qingsong; Yu, Dingshan; Zhang, Xiaoqing; Ji, Aihong; Zhang, Hao; Guo, Ce; Dai, Zhendong

    2012-10-01

    Active actuation of the adhesive pads is important for a gecko-robot climbing on walls. We demonstrate the fabrication of an ionic polymer-metal composite (IPMC) actuator enhanced with carbon nanotubes (CNTs) and its use for actively actuating an adhesive array to imitate the locomotion of gecko's toes. The as-fabricated IPMC actuator doped with CNTs exhibits a maximum blocking force of 3.59 gf driven at a low voltage of 3 V. It can be easily controlled by voltage signals to actuate an artificial gecko's toe to attach and detach from a surface. This will allow active, distributed actuation in a gecko robot.

  1. Implant-supported overdentures: the ZAAG attachment system.

    PubMed

    Davidoff, S R

    1997-11-01

    It has been amply demonstrated during the last decade that there are significant advantages to implant-supported overdentures beyond conventional complete dentures. Several attachment systems exist for connecting the overdenture to the implants, and practically all of them present notable benefits to the patients. This article discusses the use of the Zest Anchor Advanced Generation (ZAAG). This system, an outgrowth from the original Zest attachment, uses both individual implant attachments and bar attachments, and is compatible with all major implant systems. In addition to the retention, stability, and resiliency the ZAAG implant attachment system provides, it has the advantage of placing the resistance force of the attachment close to the implant body. PMID:9533347

  2. Attachment systems for mandibular implant overdentures: a systematic review

    PubMed Central

    Kim, Ha-Young; Lee, Jeong-Yol; Bryant, S. Ross

    2012-01-01

    PURPOSE The aim of this systematic review was to address treatment outcome according to attachment systems for mandibular implant overdentures in terms of implant survival rate, prosthetic maintenance and complications, and patient satisfaction. MATERIALS AND METHODS A systematic literature search was conducted using PubMed and hand searching of relevant journals considering inclusion and exclusion criteria. Clinical trial studies on mandibular implant overdentures until August, 2010 were selected if more than one type of overdenture attachment was reported. Twenty four studies from 1098 studies were finally included and the data on implant survival rate, prosthetic maintenance and complications, patient satisfaction were analyzed relative to attachment systems. RESULTS Four studies presented implant survival rates (95.8 - 97.5% for bar, 96.2 - 100% for ball, 91.7% for magnet) according to attachment system. Ten other studies presented an implant survival rate ranging from 93.3% to 100% without respect to the attachment groups. Common prosthetic maintenance and complications were replacement of an assay for magnet attachments, and activation of a matrix or clip for ball or bar attachments. Prosthetic maintenance and complications most commonly occurred in the magnet groups. Conflicting findings were found on the rate of prosthetic maintenance and complications comparing ball and bar attachments. Most studies showed no significant differences in patient satisfaction depending upon attachment systems. CONCLUSION The implant survival rate of mandibular overdentures seemed to be high regardless attachment systems. The prosthetic maintenance and complications may be influenced by attachment systems. However patient satisfaction may be independent of the attachment system. PMID:23236571

  3. Gecko toe and lamellar shear adhesion on macroscopic, engineered rough surfaces.

    PubMed

    Gillies, Andrew G; Henry, Amy; Lin, Hauwen; Ren, Angela; Shiuan, Kevin; Fearing, Ronald S; Full, Robert J

    2014-01-15

    The role in adhesion of the toes and lamellae - intermediate-sized structures - found on the gecko foot remains unclear. Insight into the function of these structures can lead to a more general understanding of the hierarchical nature of the gecko adhesive system, but in particular how environmental topology may relate to gecko foot morphology. We sought to discern the mechanics of the toes and lamellae by examining gecko adhesion on controlled, macroscopically rough surfaces. We used live Tokay geckos, Gekko gecko, to observe the maximum shear force a gecko foot can attain on an engineered substrate constructed with sinusoidal patterns of varying amplitudes and wavelengths in sizes similar to the dimensions of the toes and lamellae structures (0.5 to 6 mm). We found shear adhesion was significantly decreased on surfaces that had amplitudes and wavelengths approaching the lamella length and inter-lamella spacing, losing 95% of shear adhesion over the range tested. We discovered that the toes are capable of adhering to surfaces with amplitudes much larger than their dimensions even without engaging claws, maintaining 60% of shear adhesion on surfaces with amplitudes of 3 mm. Gecko adhesion can be predicted by the ratio of the lamella dimensions to surface feature dimensions. In addition to setae, remarkable macroscopic-scale features of gecko toes and lamellae that include compliance and passive conformation are necessary to maintain contact, and consequently, generate shear adhesion on macroscopically rough surfaces. Findings on the larger scale structures in the hierarchy of gecko foot function could provide the biological inspiration to drive the design of more effective and versatile synthetic fibrillar adhesives. PMID:24115057

  4. Structure, attachment properties, and ecological importance of the attachment system of English ivy (Hedera helix)

    PubMed Central

    Melzer, Björn; Seidel, Robin; Steinbrecher, Tina; Speck, Thomas

    2012-01-01

    Root climbers such as English ivy (Hedera helix) rely on specialized adventitious roots for attachment, enabling the plants to climb on a wide range of natural and artificial substrates. Despite their importance for the climbing habit, the biomechanical properties of these specialized adventitious roots compared with standard roots and their performance in the attachment to different host species or inert substrates have not been studied. Here organs and tissues involved in the attachment are characterized and their significance in regard to a broader functional and ecological aspect is discussed. Depending on the substrate, the root clusters show different types of failure modes at various frequencies, demonstrating the close interaction between the climber and its substrates. With a Young’s Modulus of 109.2 MPa, the attachment roots are relatively stiff for non-woody roots. The central cylinders of the attachment roots show a high tensile strength of 38 MPa and a very high extensibility of 34%. In host trees naturally co-distributed with English ivy, a ‘balanced’ occurrence of failure of the attachment system of the climber and the bark of the host is found, suggesting a co-evolution of climber and host. Maximum loads of root clusters normalized by the number of roots match those of individually tested attachment roots. In comparison with most subterranean roots the properties and structure of the attachment roots of English ivy show distinct differences. There exist similarities to the properties found for roots of Galium aparine, suggesting a trend in not fully self-supporting plants towards a higher extensibility. PMID:21914660

  5. Thermally switchable adhesions of polystyrene-block-poly(n-isopropylacrylamide) copolymer pillar array mimicking climb attitude of geckos

    NASA Astrophysics Data System (ADS)

    Chen, Jem-Kun; Wang, Jing-Hong; Chang, Jia-Yaw; Fan, Shih-Kang

    2012-09-01

    Inspired by the gecko foot pad, we fabricated polystyrene-block-poly(N-isopropylacrylamide) (PS-b-PNIPAAm) copolymer pillar array to mimic climbing attitude of a gecko, alternately attach to and detach from a surface. The pillar array structure of the PS segment significantly enhances both of the hydrophilic and hydrophobic property of PNIPAAm segment tips at 25 and 50 °C, respectively, which could generate alternating adhesive forces of approximately 120 and 11 nN. The dramatic change in adhesive and friction force difference at 25 and 50 °C may guide the design of bio-inspired artificial analogues, which could approach gecko's climbing behavior.

  6. The Adult Attachment Projective Picture System: integrating attachment into clinical assessment.

    PubMed

    George, Carol; West, Malcolm

    2011-01-01

    This article summarizes the development and validation of the Adult Attachment Projective System (AAP), a measure we developed from the Bowlby-Ainsworth developmental tradition to assess adult attachment status. The AAP has demonstrated excellent concurrent validity with the Adult Attachment Interview (George, Kaplan, & Main, 1984/1985/1996; Main & Goldwyn, 1985-1994; Main, Goldwyn, & Hesse, 2003), interjudge reliability, and test-retest reliability, with no effects of verbal intelligence or social desirability. The AAP coding and classification system and application in clinical and community samples are summarized. Finally, we introduce the 3 other articles that are part of this Special Section and discuss the use of the AAP in therapeutic assessment and treatment. PMID:21859280

  7. Adhesional instabilities and gecko locomotion

    NASA Astrophysics Data System (ADS)

    Williams, John A.

    2015-01-01

    Geckos possess a remarkable ability to run rapidly on both walls and ceilings and in recent years the mechanisms that underlie this facility have come under close scrutiny. It is now generally agreed that one of the principal mechanisms of adhesion relies on the action of van der Waal forces acting between the final extremely fine structure of the gecko toe and the underlying substrate. High speed video analysis shows that adhesive contact is both made and broken in intervals of less than 20 ms and this suggests that the mechanism of detachment is one of adhesive instability rather than steady-state peeling. By considering the gecko seta/spatula as a Euler-Bernoulli cantilever it is possible to model this instability in non-dimensional terms and thus to test the analysis at a much larger scale with more conventional engineering materials. When applied to the scale and material combination appropriate to a gecko spatula, the predicted critical load, of around 10 nN, is close to values that have been observed using and AFM cantilever and a single detached spatula.

  8. Development of an attached microalgal growth system for biofuel production.

    PubMed

    Johnson, Michael B; Wen, Zhiyou

    2010-01-01

    Algal biofuel production has gained a renewed interest in recent years but is still not economically feasible due to several limitations related to algal culture. The objective of this study is to explore a novel attached culture system for growing the alga Chlorella sp. as biodiesel feedstock, with dairy manure wastewater being used as growth medium. Among supporting materials tested for algal attachment, polystyrene foam led to a firm attachment, high biomass yield (25.65 g/m(2), dry basis), and high fatty acid yield (2.31 g/m(2)). The biomass attached on the supporting material surface was harvested by scraping; the residual colonies left on the surface served as inoculum for regrowth. The algae regrowth on the colony-established surface resulted in a higher biomass yield than that from the initial growth on fresh surface due to the downtime saved for initial algal attachment. The 10-day regrowth culture resulted in a high biodiesel production potential with a fatty acid methyl esters yield of 2.59 g/m(2) and a productivity of 0.26 g/m(-2) day(-1). The attached algal culture also removed 61-79% total nitrogen and 62-93% total phosphorus from dairy manure wastewater, depending on different culture conditions. The biomass harvested from the attached growth system (through scraping) had a water content of 93.75%, similar to that harvested from suspended culture system (through centrifugation). Collectively, the attached algal culture system with polystyrene foam as a supporting material demonstrated a good performance in terms of biomass yield, biodiesel production potential, ease to harvest biomass, and physical robustness for reuse. PMID:19636552

  9. Binaural processing by the gecko auditory periphery

    PubMed Central

    Christensen-Dalsgaard, Jakob; Tang, Yezhong

    2011-01-01

    Lizards have highly directional ears, owing to strong acoustical coupling of the eardrums and almost perfect sound transmission from the contralateral ear. To investigate the neural processing of this remarkable tympanic directionality, we combined biophysical measurements of eardrum motion in the Tokay gecko with neurophysiological recordings from the auditory nerve. Laser vibrometry shows that their ear is a two-input system with approximately unity interaural transmission gain at the peak frequency (∼1.6 kHz). Median interaural delays are 260 μs, almost three times larger than predicted from gecko head size, suggesting interaural transmission may be boosted by resonances in the large, open mouth cavity (Vossen et al. 2010). Auditory nerve recordings are sensitive to both interaural time differences (ITD) and interaural level differences (ILD), reflecting the acoustical interactions of direct and indirect sound components at the eardrum. Best ITD and click delays match interaural transmission delays, with a range of 200–500 μs. Inserting a mold in the mouth cavity blocks ITD and ILD sensitivity. Thus the neural response accurately reflects tympanic directionality, and most neurons in the auditory pathway should be directional. PMID:21325679

  10. Dual-axis MEMS force sensors for gecko adhesion studies

    NASA Astrophysics Data System (ADS)

    Hill, Ginel Corina

    Dual-axis piezoresistive microelectromechanical systems (MEMS) force sensors were used to investigate the effects of orientation angle on the adhesion of gecko hairs, called setae. These hairs are part of a fantastic, robust dry adhesive. Their adhesion is highly angle-dependent, with both the "pitch" and "roll" orientation angles playing a role. This anisotropy in adhesion properties is critical for locomotion, as it enables detachment of the gecko's foot with limited pull-off force. Many synthetic mimics of the gecko adhesive are isotropic. This work on the anisotropy of natural setae will inform future work on synthetic dry adhesives. A dual-axis microscale force sensor was needed to study single seta adhesive forces, which are stronger parallel to a substrate than perpendicular. Piezoresistive silicon cantilevers that separately detect lateral and normal forces applied at the tip were used. The fabrication process and rigorous characterization of new devices are reported. A novel calibration method was developed that uses resonant frequency measurements in concert with finite element models to correct for the expected variability of critical dimensions. These corrected models were used to predict the stiffnesses of each cantilever, and thus improve the accuracy of force measurements made with these sensors. This calibration technique was also validated by direct measurement of the dual-axis cantilever stiffnesses using a reference cantilever. The adhesion force of a single gecko seta is dramatically enhanced by proper orientation. The dual-axis cantilevers were used to measure two components of force between a substrate and a Gekko gecko seta. Lateral adhesion was highest with the stalk oriented parallel to the surface at 0° pitch. Adhesion decreased smoothly as the pitch angle of the stalk was increased, until detachment or no adhesion occurred at approximately 30°. To display enhanced adhesion, the splayed tuft at the end of the seta needed to be only

  11. Run don't walk: locomotor performance of geckos on wet substrates.

    PubMed

    Stark, Alyssa Y; Ohlemacher, Jocelyn; Knight, Ashley; Niewiarowski, Peter H

    2015-08-01

    The gecko adhesive system has been under particular scrutiny for over a decade, as the field has recently attracted attention for its application to bio-inspired design. However, little is known about how the adhesive system behaves in ecologically relevant conditions. Geckos inhabit a variety of environments, many of which are characterized by high temperature, humidity and rain. The van der Waals-based gecko adhesive system should be particularly challenged by wet substrates because water can disrupt the intimate contact necessary for adhesion. While a few previous studies have focused on the clinging ability of geckos on wet substrates, we tested a dynamic performance characteristic, sprint velocity. To better understand how substrate wettability and running orientation affect locomotor performance of multiple species on wet substrates, we measured average sprint velocity of five species of gecko on substrates that were either hydrophilic or intermediately wetting and oriented either vertically or horizontally. Surprisingly, we found no indication that wet substrates impact average sprint velocity over 1 m, and rather, in some species, sprint velocity was increased on wet substrates rather than reduced. When investigating physical characteristics and behavior that may be associated with running on wet substrates, such as total number of stops, slips and wet toes at the completion of a race, we found that there may be habitat-related differences between some species. Our results show that in general, unlike clinging and walking, geckos running along wet substrates suffer no significant loss in locomotor performance over short distances. PMID:26034124

  12. Investigating gecko setae adhesion using a dual-axis MEMS force sensor

    NASA Astrophysics Data System (ADS)

    Hill, Ginel; Soto, Daniel; Peattie, Anne; Full, Robert; Kenny, Thomas

    2007-03-01

    A dual-axis piezoresistive MEMS force sensor was used to investigate the role of orientation angle on the adhesion of gecko hairs, called setae. Made of keratin with nanoscale features, gecko setae are a spectacular, robust dry adhesive with anisotropic adhesion properties. A wealth of recent research has been devoted to synthetic mimicry of the gecko seta. However, most synthetics do not yet display anisotropic adhesion, which is critical for controllable attachment and release. Previous research using a wire gauge tested the role of the pitch angle between the stalk of natural setae and the substrate and found a dramatic cutoff angle of 30^o, above which setae detach from the substrate [1]. The present work details the effect of the ``roll'' angle on natural setae adhesion. [1] K. Autumn, et al. Nature, 405: 681 (2000).

  13. Attachment systems for implant retained overdentures: a literature review.

    PubMed

    Trakas, Theodoros; Michalakis, Konstantinos; Kang, Kiho; Hirayama, Hiroshi

    2006-03-01

    This article presents a comparison between different attachment systems used to retain and support maxillary and mandibular overdentures in completely edentulous patients. A literature review based on a MEDLINE search limited to English-language articles published from 1988 to the present was performed, and a large number of attachments available in the dental market were reviewed with regard to several factors, including: (1) implant survival rate, (2) marginal bone loss, (3) soft tissue complications, (4) retention, (5) stress distribution, (6) space requirements, (7) maintenance complications, and (8) patient satisfaction. These factors are considered essential for the successful outcome and good long-term prognosis of the prostheses. Selection criteria previously published in the literature are discussed as well. Product names and manufacturers are mentioned only if related to attachment systems, as they are cited in the original articles. PMID:16569958

  14. Gecko-Inspired, Controlled Adhesion and Its Applications

    NASA Astrophysics Data System (ADS)

    Menguc, Yigit

    This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles

  15. Superhydrophobic gecko feet with high adhesive forces towards water and their bio-inspired materials

    NASA Astrophysics Data System (ADS)

    Liu, Kesong; Du, Jiexing; Wu, Juntao; Jiang, Lei

    2012-01-01

    Functional integration is an inherent characteristic for multiscale structures of biological materials. In this contribution, we first investigate the liquid-solid adhesive forces between water droplets and superhydrophobic gecko feet using a high-sensitivity micro-electromechanical balance system. It was found, in addition to the well-known solid-solid adhesion, the gecko foot, with a multiscale structure, possesses both superhydrophobic functionality and a high adhesive force towards water. The origin of the high adhesive forces of gecko feet to water could be attributed to the high density nanopillars that contact the water. Inspired by this, polyimide films with gecko-like multiscale structures were constructed by using anodic aluminum oxide templates, exhibiting superhydrophobicity and a strong adhesive force towards water. The static water contact angle is larger than 150° and the adhesive force to water is about 66 μN. The resultant gecko-inspired polyimide film can be used as a ``mechanical hand'' to snatch micro-liter liquids. We expect this work will provide the inspiration to reveal the mechanism of the high-adhesive superhydrophobic of geckos and extend the practical applications of polyimide materials.

  16. Robust self-cleaning and micromanipulation capabilities of gecko spatulae and their bio-mimics

    NASA Astrophysics Data System (ADS)

    Xu, Quan; Wan, Yiyang; Hu, Travis Shihao; Liu, Tony X.; Tao, Dashuai; Niewiarowski, Peter H.; Tian, Yu; Liu, Yue; Dai, Liming; Yang, Yanqing; Xia, Zhenhai

    2015-11-01

    Geckos have the extraordinary ability to prevent their sticky feet from fouling while running on dusty walls and ceilings. Understanding gecko adhesion and self-cleaning mechanisms is essential for elucidating animal behaviours and rationally designing gecko-inspired devices. Here we report a unique self-cleaning mechanism possessed by the nano-pads of gecko spatulae. The difference between the velocity-dependent particle-wall adhesion and the velocity-independent spatula-particle dynamic response leads to a robust self-cleaning capability, allowing geckos to efficiently dislodge dirt during their locomotion. Emulating this natural design, we fabricate artificial spatulae and micromanipulators that show similar effects, and that provide a new way to manipulate micro-objects. By simply tuning the pull-off velocity, our gecko-inspired micromanipulators, made of synthetic microfibers with graphene-decorated micro-pads, can easily pick up, transport, and drop-off microparticles for precise assembling. This work should open the door to the development of novel self-cleaning adhesives, smart surfaces, microelectromechanical systems, biomedical devices, and more.

  17. Robust self-cleaning and micromanipulation capabilities of gecko spatulae and their bio-mimics.

    PubMed

    Xu, Quan; Wan, Yiyang; Hu, Travis Shihao; Liu, Tony X; Tao, Dashuai; Niewiarowski, Peter H; Tian, Yu; Liu, Yue; Dai, Liming; Yang, Yanqing; Xia, Zhenhai

    2015-01-01

    Geckos have the extraordinary ability to prevent their sticky feet from fouling while running on dusty walls and ceilings. Understanding gecko adhesion and self-cleaning mechanisms is essential for elucidating animal behaviours and rationally designing gecko-inspired devices. Here we report a unique self-cleaning mechanism possessed by the nano-pads of gecko spatulae. The difference between the velocity-dependent particle-wall adhesion and the velocity-independent spatula-particle dynamic response leads to a robust self-cleaning capability, allowing geckos to efficiently dislodge dirt during their locomotion. Emulating this natural design, we fabricate artificial spatulae and micromanipulators that show similar effects, and that provide a new way to manipulate micro-objects. By simply tuning the pull-off velocity, our gecko-inspired micromanipulators, made of synthetic microfibers with graphene-decorated micro-pads, can easily pick up, transport, and drop-off microparticles for precise assembling. This work should open the door to the development of novel self-cleaning adhesives, smart surfaces, microelectromechanical systems, biomedical devices, and more. PMID:26584513

  18. Superhydrophobic gecko feet with high adhesive forces towards water and their bio-inspired materials.

    PubMed

    Liu, Kesong; Du, Jiexing; Wu, Juntao; Jiang, Lei

    2012-02-01

    Functional integration is an inherent characteristic for multiscale structures of biological materials. In this contribution, we first investigate the liquid-solid adhesive forces between water droplets and superhydrophobic gecko feet using a high-sensitivity micro-electromechanical balance system. It was found, in addition to the well-known solid-solid adhesion, the gecko foot, with a multiscale structure, possesses both superhydrophobic functionality and a high adhesive force towards water. The origin of the high adhesive forces of gecko feet to water could be attributed to the high density nanopillars that contact the water. Inspired by this, polyimide films with gecko-like multiscale structures were constructed by using anodic aluminum oxide templates, exhibiting superhydrophobicity and a strong adhesive force towards water. The static water contact angle is larger than 150° and the adhesive force to water is about 66 μN. The resultant gecko-inspired polyimide film can be used as a "mechanical hand" to snatch micro-liter liquids. We expect this work will provide the inspiration to reveal the mechanism of the high-adhesive superhydrophobic of geckos and extend the practical applications of polyimide materials. PMID:22139414

  19. Robust self-cleaning and micromanipulation capabilities of gecko spatulae and their bio-mimics

    PubMed Central

    Xu, Quan; Wan, Yiyang; Hu, Travis Shihao; Liu, Tony X.; Tao, Dashuai; Niewiarowski, Peter H.; Tian, Yu; Liu, Yue; Dai, Liming; Yang, Yanqing; Xia, Zhenhai

    2015-01-01

    Geckos have the extraordinary ability to prevent their sticky feet from fouling while running on dusty walls and ceilings. Understanding gecko adhesion and self-cleaning mechanisms is essential for elucidating animal behaviours and rationally designing gecko-inspired devices. Here we report a unique self-cleaning mechanism possessed by the nano-pads of gecko spatulae. The difference between the velocity-dependent particle-wall adhesion and the velocity-independent spatula-particle dynamic response leads to a robust self-cleaning capability, allowing geckos to efficiently dislodge dirt during their locomotion. Emulating this natural design, we fabricate artificial spatulae and micromanipulators that show similar effects, and that provide a new way to manipulate micro-objects. By simply tuning the pull-off velocity, our gecko-inspired micromanipulators, made of synthetic microfibers with graphene-decorated micro-pads, can easily pick up, transport, and drop-off microparticles for precise assembling. This work should open the door to the development of novel self-cleaning adhesives, smart surfaces, microelectromechanical systems, biomedical devices, and more. PMID:26584513

  20. Gecko Adhesion on Wet and Dry Patterned Substrates

    PubMed Central

    Stark, Alyssa Y.; Palecek, Amanda M.; Argenbright, Clayton W.; Bernard, Craig; Brennan, Anthony B.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2015-01-01

    Perhaps one of the most astounding characteristics of the gecko adhesive system is its versatility. Geckos can locomote across complex substrates in a variety of conditions with apparent ease. In contrast, many of our synthetic pressure sensitive adhesives fail on substrates that are dirty, wet or rough. Although many studies have investigated the effect of environmental challenges on performance, the interaction of multiple, potentially compromising variables is studied less often. Here we focus on substrate structure and surface water, both of which are highly relevant to the biological system and to synthetic design. To do this we utilized a highly controlled, patterned substrate (Sharklet®, by Sharklet® Technologies Inc.). This allowed us to test independently and jointly the effects of reduced surface area substrates, with a defined pattern, on adhesion in both air and water. Our results show that adhesion is not significantly impaired in air, whereas surface area and pattern significantly affect adhesion in water. These findings highlight the need to study multiple parameters that are relevant to the gecko adhesive system to further improve our understanding of the biological system and to design better, more versatile synthetics. PMID:26696412

  1. Gecko Adhesion on Wet and Dry Patterned Substrates.

    PubMed

    Stark, Alyssa Y; Palecek, Amanda M; Argenbright, Clayton W; Bernard, Craig; Brennan, Anthony B; Niewiarowski, Peter H; Dhinojwala, Ali

    2015-01-01

    Perhaps one of the most astounding characteristics of the gecko adhesive system is its versatility. Geckos can locomote across complex substrates in a variety of conditions with apparent ease. In contrast, many of our synthetic pressure sensitive adhesives fail on substrates that are dirty, wet or rough. Although many studies have investigated the effect of environmental challenges on performance, the interaction of multiple, potentially compromising variables is studied less often. Here we focus on substrate structure and surface water, both of which are highly relevant to the biological system and to synthetic design. To do this we utilized a highly controlled, patterned substrate (Sharklet®, by Sharklet® Technologies Inc.). This allowed us to test independently and jointly the effects of reduced surface area substrates, with a defined pattern, on adhesion in both air and water. Our results show that adhesion is not significantly impaired in air, whereas surface area and pattern significantly affect adhesion in water. These findings highlight the need to study multiple parameters that are relevant to the gecko adhesive system to further improve our understanding of the biological system and to design better, more versatile synthetics. PMID:26696412

  2. Orientation angle and the adhesion of single gecko setae.

    PubMed

    Hill, Ginel C; Soto, Daniel R; Peattie, Anne M; Full, Robert J; Kenny, T W

    2011-07-01

    We investigated the effects of orientation angle on the adhesion of single gecko setae using dual-axis microelectromechanical systems force sensors to simultaneously detect normal and shear force components. Adhesion was highly sensitive to the pitch angle between the substrate and the seta's stalk. Maximum lateral adhesive force was observed with the stalk parallel to the substrate, and adhesion decreased smoothly with increasing pitch. The roll orientation angle only needed to be roughly correct with the spatular tuft of the seta oriented grossly towards the substrate for high adhesion. Also, detailed measurements were made to control for the effect of normal preload forces. Higher normal preload forces caused modest enhancement of the observed lateral adhesive force, provided that adequate contact was made between the seta and the substrate. These results should be useful in the design and manufacture of gecko-inspired synthetic adhesives with anisotropic properties, an area of substantial recent research efforts. PMID:21288955

  3. Orientation angle and the adhesion of single gecko setae

    PubMed Central

    Hill, Ginel C.; Soto, Daniel R.; Peattie, Anne M.; Full, Robert J.; Kenny, T. W.

    2011-01-01

    We investigated the effects of orientation angle on the adhesion of single gecko setae using dual-axis microelectromechanical systems force sensors to simultaneously detect normal and shear force components. Adhesion was highly sensitive to the pitch angle between the substrate and the seta's stalk. Maximum lateral adhesive force was observed with the stalk parallel to the substrate, and adhesion decreased smoothly with increasing pitch. The roll orientation angle only needed to be roughly correct with the spatular tuft of the seta oriented grossly towards the substrate for high adhesion. Also, detailed measurements were made to control for the effect of normal preload forces. Higher normal preload forces caused modest enhancement of the observed lateral adhesive force, provided that adequate contact was made between the seta and the substrate. These results should be useful in the design and manufacture of gecko-inspired synthetic adhesives with anisotropic properties, an area of substantial recent research efforts. PMID:21288955

  4. Emotion regulation and mental representation of attachment in patients with systemic lupus erythematosus: a study using the Adult Attachment Interview.

    PubMed

    Barbasio, Chiara; Granieri, Antonella

    2013-04-01

    Mental representations of attachment and emotion regulation influence individual patterns of stress response and vulnerability to illness. The present study investigates the adult attachment states of mind of 40 women with systemic lupus erythematosus (SLE) using the Adult Attachment Interview. We also assessed alexithymia using the Toronto Alexithymia Scale and dissociation using the Dissociative Experiences Scale. The results showed a high prevalence of the unresolved state of mind (13 patients, 32.5%) and the entangled state of mind (10 patients, 25%). The alexithymia score also varied significantly as a function of the mental representation of attachment and was modulated by amnestic dissociation. These findings suggest that adult attachment in patients with SLE influences the presence of alexithymic features. Moreover, these also indicate that dissociative states mediate the perception of painful memories and feelings, thus contributing to the partial avoidance of emotions and the failure to fully experience and recognize them. The clinical implications of these findings are also discussed. PMID:23538975

  5. Attachment of marine fasteners utilizing portable friction stud welding systems

    SciTech Connect

    Grey, I.C.; Steel, R.L.

    1995-10-01

    A fast, economical and structurally reliable method for attachment of fasteners in marine environments has long been sought by engineers and marine structure owners. A new portable friction stud welding system is one possible solution. The paper will present an explanation of friction welding, a description of portable friction stud welding equipment, as well as laboratory test results evidencing the integrity of this method of material joining. A method of providing improved electrical continuity is also presented.

  6. Removable, hermetically-sealing, filter attachment system for hostile environments

    DOEpatents

    Mayfield, Glenn L [Richland, WA

    1983-01-01

    A removable and reusable filter attachment system. A filter medium is fixed o, and surrounded by, a filter frame having a coaxial, longitudinally extending, annular rim. The rim engages an annular groove which surrounds the opening of a filter housing. The annular groove contains a fusible material and a heating mechanism for melting the fusible material. Upon resolidifying, the fusible material forms a hermetic bond with the rim and groove. Remelting allows detachment and replacement of the filter frame.

  7. Geckos significantly alter foot orientation to facilitate adhesion during downhill locomotion

    PubMed Central

    Birn-Jeffery, Aleksandra V.; Higham, Timothy E.

    2014-01-01

    Geckos employ their adhesive system when moving up an incline, but the directionality of the system may limit function on downhill surfaces. Here, we use a generalist gecko to test whether limb modulation occurs on downhill slopes to allow geckos to take advantage of their adhesive system. We examined three-dimensional limb kinematics for geckos moving up and down a 45° slope. Remarkably, the hind limbs were rotated posteriorly on declines, resulting in digit III of the pes facing a more posterior direction (opposite to the direction of travel). No significant changes in limb orientation were found in any other condition. This pes rotation leads to a dramatic shift in foot function that facilitates the use of the adhesive system as a brake/stabilizer during downhill locomotion and, although this rotation is not unique to geckos, it is significant for the deployment of adhesion. Adhesion is not just advantageous for uphill locomotion but can be employed to help deal with the effects of gravity during downhill locomotion, highlighting the incredible multi-functionality of this key innovation. PMID:25319816

  8. Self-drying: a gecko's innate ability to remove water from wet toe pads.

    PubMed

    Stark, Alyssa Y; Wucinich, Nicholas A; Paoloni, Eva L; Niewiarowski, Peter H; Dhinojwala, Ali

    2014-01-01

    When the adhesive toe pads of geckos become wet, they become ineffective in enabling geckos to stick to substrates. This result is puzzling given that many species of gecko are endemic to tropical environments where water covered surfaces are ubiquitous. We hypothesized that geckos can recover adhesive capabilities following exposure of their toe pads to water by walking on a dry surface, similar to the active self-cleaning of dirt particles. We measured the time it took to recover maximum shear adhesion after toe pads had become wet in two groups, those that were allowed to actively walk and those that were not. Keeping in mind the importance of substrate wettability to adhesion on wet surfaces, we also tested geckos on hydrophilic glass and an intermediately wetting substrate (polymethylmethacrylate; PMMA). We found that time to maximum shear adhesion recovery did not differ in the walking groups based on substrate wettability (22.7±5.1 min on glass and 15.4±0.3 min on PMMA) but did have a significant effect in the non-walking groups (54.3±3.9 min on glass and 27.8±2.5 min on PMMA). Overall, we found that by actively walking, geckos were able to self-dry their wet toe pads and regain maximum shear adhesion significantly faster than those that did not walk. Our results highlight a unexpected property of the gecko adhesive system, the ability to actively self-dry and recover adhesive performance after being rendered dysfunctional by water. PMID:25054217

  9. Gecko-Inspired, Controlled Adhesion and Its Applications

    NASA Astrophysics Data System (ADS)

    Menguc, Yigit

    This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles

  10. Active tails enhance arboreal acrobatics in geckos

    PubMed Central

    Jusufi, Ardian; Goldman, Daniel I.; Revzen, Shai; Full, Robert J.

    2008-01-01

    Geckos are nature's elite climbers. Their remarkable climbing feats have been attributed to specialized feet with hairy toes that uncurl and peel in milliseconds. Here, we report that the secret to the gecko's arboreal acrobatics includes an active tail. We examine the tail's role during rapid climbing, aerial descent, and gliding. We show that a gecko's tail functions as an emergency fifth leg to prevent falling during rapid climbing. A response initiated by slipping causes the tail tip to push against the vertical surface, thereby preventing pitch-back of the head and upper body. When pitch-back cannot be prevented, geckos avoid falling by placing their tail in a posture similar to a bicycle's kickstand. Should a gecko fall with its back to the ground, a swing of its tail induces the most rapid, zero-angular momentum air-righting response yet measured. Once righted to a sprawled gliding posture, circular tail movements control yaw and pitch as the gecko descends. Our results suggest that large, active tails can function as effective control appendages. These results have provided biological inspiration for the design of an active tail on a climbing robot, and we anticipate their use in small, unmanned gliding vehicles and multisegment spacecraft. PMID:18347344

  11. Does the attachment system towards owners change in aged dogs?

    PubMed

    Mongillo, Paolo; Pitteri, Elisa; Carnier, Paolo; Gabai, Gianfranco; Adamelli, Serena; Marinelli, Lieta

    2013-08-15

    Changes during senescence can significantly affect both the emotional and relational needs of old individuals and the characteristics of the attachment system. In order to determine whether the emotional response of dogs is affected by old age, we compared the behavioural parameters of adult (AD <7 years of age, n=25) and aged (AG ≥7 years of age, n=25) dogs in a distressing situation, which gives rise to attachment behaviour patterns (Strange Situation Test, SST). The physiological response of dogs was assessed by measurement of salivary cortisol variations in samples collected both at the dogs' homes and at the study location, before and after the SST. Both groups of dogs expressed clear-cut patterns of attachment to their owners. During the initial part of the procedure, AG dogs sought more physical contact, but behaved more passively and showed less interest in an unknown person during separation from their owners. Compared with AD dogs, AG ones showed a significant increase in salivary cortisol concentrations after the SST. The combination of physiological and behavioural data of the present study supports the hypothesis that, later in life, dogs cope less efficiently with emotional distress caused by mild social challenge. PMID:23911691

  12. Portable and attachable tele-echography robot system: FASTele.

    PubMed

    Ito, Keiichiro; Sugano, Shigeki; Iwata, Hiroyasu

    2010-01-01

    The purpose of this report is to propose portable and attachable tele-echography robot system: FASTele. Focused assessment with sonography for trauma (FAST) is important for patients who have shock by internal bleeding. However, the patient has little time, and transportation to a hospital may take too long. A system which enables FAST more quickly is required. Therefore, we aim to develop a tele-echography (FAST) robot system that can be used by a paramedic easily for shock patient in ambulance or at injury scene. To develop the system, portability and usability (for paramedic) are significant issues. We developed a tele-echography robot system which has 4-DOF. The robot is attached to each roughly FAST areas of patient body (body-based set up) and remotely fine-tuned position by a specialist in a hospital. The robot can control the posture of probe by curvature rails. The mechanism that maintains passively the contact force between the probe and patient's body surface by using springs enables the robot small and lightweight. Feasibility experiments of FAST are reported. PMID:21096306

  13. Defining the brain systems of lust, romantic attraction, and attachment.

    PubMed

    Fisher, Helen E; Aron, Arthur; Mashek, Debra; Li, Haifang; Brown, Lucy L

    2002-10-01

    Mammals and birds have evolved three primary, discrete, interrelated emotion-motivation systems in the brain for mating, reproduction, and parenting: lust, attraction, and male-female attachment. Each emotion-motivation system is associated with a specific constellation of neural correlates and a distinct behavioral repertoire. Lust evolved to initiate the mating process with any appropriate partner; attraction evolved to enable individuals to choose among and prefer specific mating partners, thereby conserving their mating time and energy; male-female attachment evolved to enable individuals to cooperate with a reproductive mate until species-specific parental duties have been completed. The evolution of these three emotion-motivation systems contribute to contemporary patterns of marriage, adultery, divorce, remarriage, stalking, homicide and other crimes of passion, and clinical depression due to romantic rejection. This article defines these three emotion-motivation systems. Then it discusses an ongoing project using functional magnetic resonance imaging of the brain to investigate the neural circuits associated with one of these emotion-motivation systems, romantic attraction. PMID:12238608

  14. Electron attachment and ion mobility in hydrocarbons and related systems

    SciTech Connect

    Bakale, G.

    1988-01-01

    During the last two decades, a firm base for the emerging field of liquid state electronics (LSE) has developed through studies of the transport and reaction properties of excess electrons in a variety of liquid-phase systems. Pulse-conductivity techniques were used in many of these studies to measure the mobilities of electrons and ions in pure liquids as well as the rate constants of electron attachment to a wide variety of electron-accepting solutes. Results obtained through such studies have interdisciplinary implications that are described in the discussion that follows which includes examples of the contributions of LSE to physics, chemistry and biology. 42 refs.

  15. Peramorphic traits in the tokay gecko skull.

    PubMed

    Daza, Juan D; Mapps, Aurelia A; Lewis, Patrick J; Thies, Monte L; Bauer, Aaron M

    2015-08-01

    Traditionally, geckos have been conceived to exhibit paedomorphic features relative to other lizards (e.g., large eyes, less extensively ossified skulls, and amphicoelous and notochordal vertebrae). In contrast, peramorphosis has not been considered an important process in shaping their morphology. Here, we studied different sized specimens of Gekko gecko to document ontogenetic changes in cranial anatomy, especially near maturity. Comparison of this species with available descriptions of other geckos resulted in the identification of 14 cranial characteristics that are expressed more strongly with size increase. These characteristics become move evident in later stages of post-hatching development, especially near maturation, and are, therefore, attributed to peramorphosis (hyperossification). ACCTRAN and DELTRAN character optimizations were applied to these characters using a tree of 11 genera derived from a gekkotan molecular phylogeny. This analysis revealed that G. gecko expresses the majority of these putative peramorphic features near maturity, and that some of these features are also expressed in species closely related to G. gecko. The characters studied have the potential to be applied in future phylogenetic and taxonomic studies of this group of lizards. PMID:26010648

  16. Preferential attachment and growth dynamics in complex systems

    NASA Astrophysics Data System (ADS)

    Yamasaki, Kazuko; Matia, Kaushik; Buldyrev, Sergey V.; Fu, Dongfeng; Pammolli, Fabio; Riccaboni, Massimo; Stanley, H. Eugene

    2006-09-01

    Complex systems can be characterized by classes of equivalency of their elements defined according to system specific rules. We propose a generalized preferential attachment model to describe the class size distribution. The model postulates preferential growth of the existing classes and the steady influx of new classes. According to the model, the distribution changes from a pure exponential form for zero influx of new classes to a power law with an exponential cut-off form when the influx of new classes is substantial. Predictions of the model are tested through the analysis of a unique industrial database, which covers both elementary units (products) and classes (markets, firms) in a given industry (pharmaceuticals), covering the entire size distribution. The model’s predictions are in good agreement with the data. The paper sheds light on the emergence of the exponent τ≈2 observed as a universal feature of many biological, social and economic problems.

  17. Use of the adult attachment projective picture system in psychodynamic psychotherapy with a severely traumatized patient

    PubMed Central

    George, Carol; Buchheim, Anna

    2014-01-01

    The following case study is presented to facilitate an understanding of how the attachment information evident from Adult Attachment Projective Picture System (AAP) assessment can be integrated into a psychodynamic perspective in making therapeutic recommendations that integrate an attachment perspective. The Adult Attachment Projective Picture System (AAP) is a valid representational measure of internal representations of attachment based on the analysis of a set of free response picture stimuli designed to systematically activate the attachment system (George and West, 2012). The AAP provides a fruitful diagnostic tool for psychodynamic-oriented clinicians to identify attachment-based deficits and resources for an individual patient in therapy. This paper considers the use of the AAP with a traumatized patient in an inpatient setting and uses a case study to illustrate the components of the AAP that are particularly relevant to a psychodynamic conceptualization. The paper discusses also attachment-based recommendations for intervention. PMID:25140164

  18. Superhydrophobicity of the gecko toe pad: biological optimization versus laboratory maximization.

    PubMed

    Stark, Alyssa Y; Subarajan, Shairani; Jain, Dharamdeep; Niewiarowski, Peter H; Dhinojwala, Ali

    2016-08-01

    While many gecko-inspired hierarchically structured surfaces perform as well as or better than the natural adhesive system, these designs often fail to function across a variety of contexts. For example, the gecko can adhere to rough, wet and dirty surfaces; however, most synthetic mimics cannot maintain function when faced with a similar situation. The solution to this problem lies in a more thorough investigation of the natural system. Here, we review the adhesive system of the gecko toe pad, as well as the far less-well-studied anti-adhesive system that results from the chemistry and structure of the toe pad (superhydrophobicity). This paradoxical relationship serves as motivation to study functional optimization at the system level. As an example, we experimentally investigate the role of surface lipids in adhesion and anti-adhesion, and find a clear performance trade-off related to shear adhesion in air on a hydrophilic surface. This represents the first direct investigation of the role of surface lipids in gecko adhesion and anti-adhesion, and supports the argument that a system-level approach is necessary to elucidate optimization in biological systems. Without such an approach, bioinspired designs will be limited in functionality and context, especially compared to the natural systems they mimic.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'. PMID:27354726

  19. A pointing system design concept for Space Station attached payloads

    NASA Technical Reports Server (NTRS)

    Wong, Edward; Rathbun, Dave; Smith, Kenneth

    1989-01-01

    A study has been conducted to recommend a pointing system design and architecture that can accommodate the articulated pointing requirements levied on the Space Station Freedom Attached Payload Pointing System. A conceptual design of a control system is developed using classical rate and position control techniques. A high fidelity simulation testbed has been developed as the principal tool for the pointing performance evaluation. Techniques of model reduction are applied to reduce the model order to a manageable size for incorporation into the testbed. The disturbance rich space station environment has been modeled, and nonlinearities such as bearing friction, motor and sensor noise are also considered. Simulations were performed with representatie payloads at nominal pointing orientations. The results show that the tight instrument pointing requirements and the severe Space Station disturbance environment render a marginal performance for a conventional (direct drive and hardmount) gimbal pointing system, particularly for lightweight payloads. A gimbal system that incorporates a passive base isolator and reactionless actuation appears to provide a significant imporvement in pointing performance over the conventional pointing systems.

  20. A remote camera operation system using a marker attached cap

    NASA Astrophysics Data System (ADS)

    Kawai, Hironori; Hama, Hiromitsu

    2005-12-01

    In this paper, we propose a convenient system to control a remote camera according to the eye-gazing direction of the operator, which is approximately obtained through calculating the face direction by means of image processing. The operator put a marker attached cap on his head, and the system takes an image of the operator from above with only one video camera. Three markers are set up on the cap, and 'three' is the minimum number to calculate the tilt angle of the head. The more markers are used, the robuster system may be made to occlusion, and the wider moving range of the head is tolerated. It is supposed that the markers must not exist on any three dimensional straight line. To compensate the marker's color change due to illumination conditions, the threshold for the marker extraction is adaptively decided using a k-means clustering method. The system was implemented with MATLAB on a personal computer, and the real-time operation was realized. Through the experimental results, robustness of the system was confirmed and tilt and pan angles of the head could be calculated with enough accuracy to use.

  1. Gecko adhesion pad: a smart surface?

    NASA Astrophysics Data System (ADS)

    Pesika, Noshir S.; Zeng, Hongbo; Kristiansen, Kai; Zhao, Boxin; Tian, Yu; Autumn, Kellar; Israelachvili, Jacob

    2009-11-01

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  2. NMR spectroscopy reveals the presence and association of lipids and keratin in adhesive gecko setae.

    PubMed

    Jain, Dharamdeep; Stark, Alyssa Y; Niewiarowski, Peter H; Miyoshi, Toshikazu; Dhinojwala, Ali

    2015-01-01

    Lipid and protein aggregates are one of the fundamental materials of biological systems. Examples include cell membranes, insect cuticle, vertebrate epidermis, feathers, hair and adhesive structures known as 'setae' on gecko toes. Until recently gecko setae were assumed to be composed entirely of keratin, but analysis of footprints left behind by geckos walking on surfaces revealed that setae include various kinds of lipids. However, the arrangement and molecular-level behavior of lipids and keratin in the setae is still not known. In the present study we demonstrate, for the first time, the use of Nuclear Magnetic Resonance (NMR) spectroscopy techniques to confirm the presence of lipids and investigate their association with keratin in 'pristine' sheds, or natural molts of the adhesive toe pad and non-adhesive regions of the skin. Analysis was also carried on the sheds after they were 'delipidized' to remove surface lipids. Our results show a distribution of similar lipids in both the skin and toe shed but with different dynamics at a molecular level. The present study can help us understand the gecko system both biologically and for design of synthetic adhesives, but the findings may be relevant to the characteristics of lipid-protein interactions in other biological systems. PMID:25902194

  3. Effect of 16-Day Spaceflight on the Morphology of Thick-Toed Geckos (Pachydactylus Bibronii Smith, 1846)

    NASA Technical Reports Server (NTRS)

    Gulimova, V. I.; Nikitin, V. B.; Asadchikov, V. E.; Buzmakov, A. V.; Okshtein, I. L.; Almeida, E. A. C.; Ilyin, E. A.; Tairbekov, M. G.; Saveliev, S. V.

    2006-01-01

    There are grounds to believe that space flown experiments on thick-toed geckos may help solve the problem of floatation of vertebrates in microgravity. Geckos of this species carry on the lower surface of their toes numerous setae, which allow them to remain attached to any surfaces regardless of the gravitational effects. Experiments were performed on 5 animals in each of the following groups: flight, basal, synchronous and laboratory controls. 32 hours after a 16- day flight the animals were euthanazed and examined using traditional histology and X-ray microtomography. Body mass losses were 10% in the flight animals, 7.4% in the synchronous controls, and 12.3% in the laboratory controls. Since the flight and synchronous animals were kept at 15-19 C, whereas the laboratory controls - at 26-28 C, it can be inferred that environmental temperatures impacted animal metabolism no less than flight induced stress. Blood tests of the flown animals showed a 12% decrease of erythrocytes and a 40% decrease of dark-nuclear granulocytes, with the number of light-nuclear granulocytes remaining unchanged. In the small intestine the number of goblet cells increased allowing them to occupy a large portion of the cyptal surface. Enhanced secretion was accompanied by the appearance of dead intestinal cells in the lumen. Clusters of degraded hepatocytes were found at the liver edges of flight animals. Signs of liver involution were similar to the changes produced by alcohol consumption but did not spread to its central part. In the heart, insignificant hypertrophy and excessive blood supply that still remained within the physiological norm were detected. No significant changes were found in the pancreas, lungs, nervous systems or the snouts of the flown animals, but the volume of their gallbladders was greater than in controls. The epithelium of toe pads of the flight animals became thinner. Histological examination of the humerus did not demonstrate significant mineral losses

  4. Stress analysis of mandibular two-implant overdenture with different attachment systems.

    PubMed

    Takeshita, Shin; Kanazawa, Manabu; Minakuchi, Shunsuke

    2011-01-01

    This study aimed to investigate the influence of different overdenture attachment systems on the stress generated in peri-implant bone during overdenture dislodgement and loading. Two implants were placed in the canine regions on an acrylic edentulous mandibular model. Four strain gauges were attached to the resin surface adjacent to the left implant. Bar, ball, and magnetic attachments were examined. Three experimental overdentures were fabricated, and the denture parts of the attachment systems were incorporated into the mucosal surface. Retentive forces and strains generated in peri-implant bone during three types of dislodgement (vertical, anterior and posterior) and loading (left first molar region, right first molar region and mid-anterior region) were measured. The bar attachment showed the highest retentive force and reduced strain on posterior dislodgement. The ball attachment demonstrated the largest strain on loading at molar regions. The magnetic attachment showed the smallest retentive force and little strain. PMID:22123019

  5. Integrating systems theory and attachment theory: the use of radio communication to modify attachments in a patient with psychogenic vomiting.

    PubMed

    Dickman, D; Prieto, P

    1987-10-01

    A case is presented that shows the usefulness of integrating systems theory and attachment theory in the formulation and treatment of a clinical problem. The 5 year old son of East Indian immigrants presented with persistent psychogenic vomiting associated with pathological family attachments. It was evident that the precarious family equilibrium was stabilized by the child's psychogenic vomiting. The therapeutic team suggested to the family that their problems might be more satisfactorily resolved if the mother and child maintained their link by two-way radio. Three weeks later the vomiting had ceased, the child no longer felt that he needed the radio and both parents had established new patterns of relating to their child, whose attendance and peer socialization at school showed marked improvement. To some extent the rapid resolution of the problems was facilitated by the cultural strengths of the family. PMID:3676993

  6. Simulation of synthetic gecko arrays shearing on rough surfaces

    PubMed Central

    Gillies, Andrew G.; Fearing, Ronald S.

    2014-01-01

    To better understand the role of surface roughness and tip geometry in the adhesion of gecko synthetic adhesives, a model is developed that attempts to uncover the relationship between surface feature size and the adhesive terminal feature shape. This model is the first to predict the adhesive behaviour of a plurality of hairs acting in shear on simulated rough surfaces using analytically derived contact models. The models showed that the nanoscale geometry of the tip shape alters the macroscale adhesion of the array of fibres by nearly an order of magnitude, and that on sinusoidal surfaces with amplitudes much larger than the nanoscale features, spatula-shaped features can increase adhesive forces by 2.5 times on smooth surfaces and 10 times on rough surfaces. Interestingly, the summation of the fibres acting in concert shows behaviour much more complex that what could be predicted with the pull-off model of a single fibre. Both the Johnson–Kendall–Roberts and Kendall peel models can explain the experimentally observed frictional adhesion effect previously described in the literature. Similar to experimental results recently reported on the macroscale features of the gecko adhesive system, adhesion drops dramatically when surface roughness exceeds the size and spacing of the adhesive fibrillar features. PMID:24694893

  7. Simulation of synthetic gecko arrays shearing on rough surfaces.

    PubMed

    Gillies, Andrew G; Fearing, Ronald S

    2014-06-01

    To better understand the role of surface roughness and tip geometry in the adhesion of gecko synthetic adhesives, a model is developed that attempts to uncover the relationship between surface feature size and the adhesive terminal feature shape. This model is the first to predict the adhesive behaviour of a plurality of hairs acting in shear on simulated rough surfaces using analytically derived contact models. The models showed that the nanoscale geometry of the tip shape alters the macroscale adhesion of the array of fibres by nearly an order of magnitude, and that on sinusoidal surfaces with amplitudes much larger than the nanoscale features, spatula-shaped features can increase adhesive forces by 2.5 times on smooth surfaces and 10 times on rough surfaces. Interestingly, the summation of the fibres acting in concert shows behaviour much more complex that what could be predicted with the pull-off model of a single fibre. Both the Johnson-Kendall-Roberts and Kendall peel models can explain the experimentally observed frictional adhesion effect previously described in the literature. Similar to experimental results recently reported on the macroscale features of the gecko adhesive system, adhesion drops dramatically when surface roughness exceeds the size and spacing of the adhesive fibrillar features. PMID:24694893

  8. The network perspective: an integration of attachment and family systems theories.

    PubMed

    Kozlowska, Kasia; Hanney, Lesley

    2002-01-01

    In this article we discuss the network paradigm as a useful base from which to integrate attachment and family systems theories. The network perspective refers to the application of general systems theory to living systems, and provides a framework that conceptualizes the dyadic and family systems as simultaneously distinct and interconnected. Network thinking requires that the clinician holds multiple perspectives in mind, considers each system level as both a part and a whole, and shifts the focus of attention between levels as required. Key epistemological issues that have hindered the integration of the theories are discussed. These include inconsistencies within attachment theory itself and confusion surrounding the theoretical conceptualizations of the relationship between attachment and family systems theories. Detailed information about attachment categories is provided using the Dynamic Maturational model. Case vignettes illustrating work with young children and their families explore the clinical implications of integrating attachment data into family therapy practice. PMID:12395561

  9. Attached manipulator system design and concept verification for zero-g simulation

    NASA Technical Reports Server (NTRS)

    Booker, R.; Burkitt, W.; Corveleyn, P.; Cramer, P.; Duwaik, O.; Flatau, C.; Garber, P.; Grant, C.; Greeb, F.; Johnson, C.

    1973-01-01

    The attached manipulator system (AMS) is to simulate and demonstrate zero-g shuttle manipulator cargo handling operations. It is not the design or development of the shuttle attached manipulator system (SAMS); however, every effort is being made, to insure that the AMS will be functionally similar to the SAMS.

  10. Neural basis of attachment-caregiving systems interaction: insights from neuroimaging studies

    PubMed Central

    Lenzi, Delia; Trentini, Cristina; Tambelli, Renata; Pantano, Patrizia

    2015-01-01

    The attachment and the caregiving system are complementary systems which are active simultaneously in infant and mother interactions. This ensures the infant survival and optimal social, emotional, and cognitive development. In this brief review we first define the characteristics of these two behavioral systems and the theory that links them, according to what Bowlby called the “attachment-caregiving social bond” (Bowlby, 1969). We then follow with those neuroimaging studies that have focused on this particular issue, i.e., those which have studied the activation of the careging system in women (using infant stimuli) and have explored how the individual attachment model (through the Adult Attachment Interview) modulates its activity. Studies report altered activation in limbic and prefrontal areas and in basal ganglia and hypothalamus/pituitary regions. These altered activations are thought to be the neural substrate of the attachment-caregiving systems interaction. PMID:26379578

  11. Viscoelastic features of adhesive setae of the tokay gecko (Gekko gecko L.).

    PubMed

    Ivlev, Yu F; Il'in, A I; Trofimov, O V

    2016-03-01

    Deformations of particular setae of adhesive toe pad of the tokay gecko were investigated by atomic-force microscopy. The effective elastic modulus of the investigated setae varying within 0.34-19 GPa, a pronounced hysteresis was observed during reversible bending of setae. The hysteresis-related energy losses may be as high as 98% of the total bending work. The pronounced viscous features of the setae contradict the hypothesis of dynamic self-cleaning of the gecko adhesive cover, according to which the setae are considered as absolutely elastic cantilever beams. PMID:27193882

  12. Shunt attachment and method for interfacing current collection systems

    DOEpatents

    Denney, Paul E.; Iyer, Natraj C.; Hannan, III, William F.

    1992-01-01

    A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature.

  13. Shunt attachment and method for interfacing current collection systems

    DOEpatents

    Denney, P.E.; Iyer, N.C.; Hannan, W.F. III.

    1992-12-08

    A composite brush to shunt attachment wherein a volatile component of a composite but mostly metallic brush, used for current collection purposes, does not upon welding or brazing, adversely affect the formation of the interfacial bond with a conductive shunt which carries the current from the zone of the brush. The brush to shunt attachment for a brush material of copper-graphite composite and a shunt of copper, or substituting silver for copper as an alternative, is made through a hot isostatic pressing (HIP). The HIP process includes applying high pressure and temperature simultaneously at the brush to shunt interface, after it has been isolated or canned in a metal casing in which the air adjacent to the interface has been evacuated and the interfacial area has been sealed before the application of pressure and temperature. 6 figs.

  14. Surface wettability plays a significant role in gecko adhesion underwater.

    PubMed

    Stark, Alyssa Y; Badge, Ila; Wucinich, Nicholas A; Sullivan, Timothy W; Niewiarowski, Peter H; Dhinojwala, Ali

    2013-04-16

    Although we now have thousands of studies focused on the nano-, micro-, and whole-animal mechanics of gecko adhesion on clean, dry substrates, we know relatively little about the effects of water on gecko adhesion. For many gecko species, however, rainfall frequently wets the natural surfaces they navigate. In an effort to begin closing this gap, we tested the adhesion of geckos on submerged substrates that vary in their wettability. When tested on a wet hydrophilic surface, geckos produced a significantly lower shear adhesive force (5.4 ± 1.33 N) compared with a dry hydrophilic surface (17.1 ± 3.93 N). In tests on an intermediate wetting surface and a hydrophobic surface, we found no difference in shear adhesion between dry and wet contact. Finally, in tests on polytetrafluoroethylene (PTFE), we found that geckos clung significantly better to wet PTFE (8.0 ± 1.09 N) than dry PTFE (1.6 ± 0.66 N). To help explain our results, we developed models based on thermodynamic theory of adhesion for contacting surfaces in different media and found that we can predict the ratio of shear adhesion in water to that in air. Our findings provide insight into how geckos may function in wet environments and also have significant implications for the development of a synthetic gecko mimic that retains adhesion in water. PMID:23576727

  15. Looking beyond fibrillar features to scale gecko-like adhesion.

    PubMed

    Bartlett, Michael D; Croll, Andrew B; King, Daniel R; Paret, Beth M; Irschick, Duncan J; Crosby, Alfred J

    2012-02-21

    Hand-sized gecko-inspired adhesives with reversible force capacities as high as 2950 N (29.5 N cm(-2) ) are designed without the use of fibrillar features through a simple scaling theory. The scaling theory describes both natural and synthetic gecko-inspired adhesives, over 14 orders of magnitude in adhesive force capacity, from nanoscopic to macroscopic length scales. PMID:22278804

  16. Surface wettability plays a significant role in gecko adhesion underwater

    PubMed Central

    Stark, Alyssa Y.; Badge, Ila; Wucinich, Nicholas A.; Sullivan, Timothy W.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2013-01-01

    Although we now have thousands of studies focused on the nano-, micro-, and whole-animal mechanics of gecko adhesion on clean, dry substrates, we know relatively little about the effects of water on gecko adhesion. For many gecko species, however, rainfall frequently wets the natural surfaces they navigate. In an effort to begin closing this gap, we tested the adhesion of geckos on submerged substrates that vary in their wettability. When tested on a wet hydrophilic surface, geckos produced a significantly lower shear adhesive force (5.4 ± 1.33 N) compared with a dry hydrophilic surface (17.1 ± 3.93 N). In tests on an intermediate wetting surface and a hydrophobic surface, we found no difference in shear adhesion between dry and wet contact. Finally, in tests on polytetrafluoroethylene (PTFE), we found that geckos clung significantly better to wet PTFE (8.0 ± 1.09 N) than dry PTFE (1.6 ± 0.66 N). To help explain our results, we developed models based on thermodynamic theory of adhesion for contacting surfaces in different media and found that we can predict the ratio of shear adhesion in water to that in air. Our findings provide insight into how geckos may function in wet environments and also have significant implications for the development of a synthetic gecko mimic that retains adhesion in water. PMID:23576727

  17. Pin and roller attachment system for ceramic blades

    DOEpatents

    Shaffer, James E.

    1995-01-01

    In a turbine, a plurality of blades are attached to a turbine wheel by way of a plurality of joints which form a rolling contact between the blades and the turbine wheel. Each joint includes a pin and a pair of rollers to provide rolling contact between the pin and an adjacent pair of blades. Because of this rolling contact, high stress scuffing between the blades and the turbine wheel reduced, thereby inhibiting catastrophic failure of the blade joints.

  18. Pin and roller attachment system for ceramic blades

    DOEpatents

    Shaffer, J.E.

    1995-07-25

    In a turbine, a plurality of blades are attached to a turbine wheel by way of a plurality of joints which form a rolling contact between the blades and the turbine wheel. Each joint includes a pin and a pair of rollers to provide rolling contact between the pin and an adjacent pair of blades. Because of this rolling contact, high stress scuffing between the blades and the turbine wheel reduced, thereby inhibiting catastrophic failure of the blade joints. 3 figs.

  19. Performance Modeling of Network-Attached Storage Device Based Hierarchical Mass Storage Systems

    NASA Technical Reports Server (NTRS)

    Menasce, Daniel A.; Pentakalos, Odysseas I.

    1995-01-01

    Network attached storage devices improve I/O performance by separating control and data paths and eliminating host intervention during the data transfer phase. Devices are attached to both a high speed network for data transfer and to a slower network for control messages. Hierarchical mass storage systems use disks to cache the most recently used files and a combination of robotic and manually mounted tapes to store the bulk of the files in the file system. This paper shows how queuing network models can be used to assess the performance of hierarchical mass storage systems that use network attached storage devices as opposed to host attached storage devices. Simulation was used to validate the model. The analytic model presented here can be used, among other things, to evaluate the protocols involved in 1/0 over network attached devices.

  20. Coming to America: Multiple Origins of New World Geckos

    PubMed Central

    Gamble, Tony; Bauer, Aaron M; Colli, Guarino R; Greenbaum, Eli; Jackman, Todd R; Vitt, Laurie J; Simons, Andrew M

    2010-01-01

    Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time-calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographic scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographic scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal, or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna. PMID:21126276

  1. Sliding Adhesion Dynamics of Isolated Gecko Setal Arrays

    NASA Astrophysics Data System (ADS)

    Sponberg, Simon; Autumn, Kellar

    2003-03-01

    The tokay gecko (Gekko gecko) can adhere to nearly any surface through van der Waals interactions of the specialized setae (b-keratin "hairs") of its toe pads. Our recent research has suggested that a gecko is substantially overbuilt for static adhesion requiring as little as 0.03of its theoretical adhesive capacity. We performed the first sliding adhesion experiments on this novel biological adhesive to determine its response to dynamic loading. We isolated arrays of setae and constructed a precision controlled Robo-toe to study sliding effects. Our results indicate that, unlike many typical adhesives, gecko setal arrays exhibit an increased frictional force upon sliding (mk > ms) which further increases with velocity, suggesting that perturbation rejection may be an evolutionary design principle underlying the evolution of the gecko adhesive. We compare these dynamic properties with those of other adhesives and explore the impacts of these results on the design of artificial adhesives.

  2. Effects of contact shape on the scaling of biological attachments

    NASA Astrophysics Data System (ADS)

    Spolenak, Ralph; Gorb, Stanislav; Gao, Huajian; Arzt, Eduard

    2005-02-01

    Adhesion of biological systems has recently received much research attention: the survival of organisms ranging from single cells and mussels to insects, spiders and geckos relies crucially on their mechanical interaction with their environments. For spiders, lizards and possible other 'dry' adhesive systems, explanations for adhesion are based on van der Waals interaction, and the adhesion of single-contact elements has been described by the classical Johnson-Kendall-Roberts (JKR) model derived for spherical contacts. However, real biological contacts display a variety of shapes and only rarely resemble a hemisphere. Here, we theoretically assess the influence of various contact shapes on the pull-off force for single contacts as well as their scaling potential in contact arrays. It is concluded that other shapes, such as a toroidal contact geometry, should lead to better attachment; such geometries are observed in our microscopic investigations of hair-tip shapes in beetles and flies.

  3. Optical gecko toe: Optically controlled attractive near-field forces between plasmonic metamaterials and dielectric or metal surfaces

    NASA Astrophysics Data System (ADS)

    Zhang, J.; MacDonald, K. F.; Zheludev, N. I.

    2012-05-01

    On the mesoscopic scale, electromagnetic forces are of fundamental importance to an enormously diverse range of systems, from optical tweezers to the adhesion of gecko toes. Here we show that a strong light-driven force may be generated when a plasmonic metamaterial is illuminated in close proximity to a dielectric or metal surface. This near-field force can exceed radiation pressure and Casimir forces to provide an optically controlled adhesion mechanism mimicking the gecko toe: At illumination intensities of just a few tens of nW/μm2 it is sufficient to overcome the Earth's gravitational pull.

  4. Assessment of the GECKO-A Modeling Tool and Simplified 3D Model Parameterizations for SOA Formation

    NASA Astrophysics Data System (ADS)

    Aumont, B.; Hodzic, A.; La, S.; Camredon, M.; Lannuque, V.; Lee-Taylor, J. M.; Madronich, S.

    2014-12-01

    Explicit chemical mechanisms aim to embody the current knowledge of the transformations occurring in the atmosphere during the oxidation of organic matter. These explicit mechanisms are therefore useful tools to explore the fate of organic matter during its tropospheric oxidation and examine how these chemical processes shape the composition and properties of the gaseous and the condensed phases. Furthermore, explicit mechanisms provide powerful benchmarks to design and assess simplified parameterizations to be included 3D model. Nevertheless, the explicit mechanism describing the oxidation of hydrocarbons with backbones larger than few carbon atoms involves millions of secondary organic compounds, far exceeding the size of chemical mechanisms that can be written manually. Data processing tools can however be designed to overcome these difficulties and automatically generate consistent and comprehensive chemical mechanisms on a systematic basis. The Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere (GECKO-A) has been developed for the automatic writing of explicit chemical schemes of organic species and their partitioning between the gas and condensed phases. GECKO-A can be viewed as an expert system that mimics the steps by which chemists might develop chemical schemes. GECKO-A generates chemical schemes according to a prescribed protocol assigning reaction pathways and kinetics data on the basis of experimental data and structure-activity relationships. In its current version, GECKO-A can generate the full atmospheric oxidation scheme for most linear, branched and cyclic precursors, including alkanes and alkenes up to C25. Assessments of the GECKO-A modeling tool based on chamber SOA observations will be presented. GECKO-A was recently used to design a parameterization for SOA formation based on a Volatility Basis Set (VBS) approach. First results will be presented.

  5. Role of contact electrification and electrostatic interactions in gecko adhesion.

    PubMed

    Izadi, Hadi; Stewart, Katherine M E; Penlidis, Alexander

    2014-09-01

    Geckos, which are capable of walking on walls and hanging from ceilings with the help of micro-/nano-scale hierarchical fibrils (setae) on their toe pads, have become the main prototype in the design and fabrication of fibrillar dry adhesives. As the unique fibrillar feature of the toe pads of geckos allows them to develop an intimate contact with the substrate the animal is walking on or clinging to, it is expected that the toe setae exchange significant numbers of electric charges with the contacted substrate via the contact electrification (CE) phenomenon. Even so, the possibility of the occurrence of CE and the contribution of the resulting electrostatic interactions to the dry adhesion of geckos have been overlooked for several decades. In this study, by measuring the magnitude of the electric charges, together with the adhesion forces, that gecko foot pads develop in contact with different materials, we have clarified for the first time that CE does contribute effectively to gecko adhesion. More importantly, we have demonstrated that it is the CE-driven electrostatic interactions which dictate the strength of gecko adhesion, and not the van der Waals or capillary forces which are conventionally considered as the main source of gecko adhesion. PMID:25008078

  6. Gecko-inspired surfaces: a path to strong and reversible dry adhesives.

    PubMed

    Boesel, Luciano F; Greiner, Christian; Arzt, Eduard; del Campo, Aránzazu

    2010-05-18

    The amazing adhesion of gecko pads to almost any kind of surfaces has inspired a very active research direction over the last decade: the investigation of how geckos achieve this feat and how this knowledge can be turned into new strategies to reversibly join surfaces. This article reviews the fabrication approaches used so far for the creation of micro- and nanostructured fibrillar surfaces with adhesive properties. In the light of the pertinent contact mechanics, the adhesive properties are presented and discussed. The decisive design parameters are fiber radius and aspect ratio, tilt angle, hierarchical arrangement and the effect of the backing layer. Also first responsive systems that allow thermal switching between nonadhesive and adhesive states are described. These structures show a high potential of application, providing the remaining issues of robustness, reliability, and large-area manufacture can be solved. PMID:20349430

  7. Testing the retention of attachments for implant overdentures - validation of an original force measurement system.

    PubMed

    Fromentin, O; Lassauzay, C; Abi Nader, S; Feine, J; de Albuquerque Junior, R F

    2010-01-01

    The aim of this study was to validate an original portable device to measure attachment retention of implant overdentures both in the lab and in clinical settings. The device was built with a digital force measurement gauge (Imada) secured to a vertical wheel stand associated with a customized support to hold and position the denture in adjustable angulations. Sixteen matrix and patrix cylindrical stud attachments (Locator) were randomly assigned as in vitro test specimens. Attachment abutments were secured in an implant analogue hung to the digital force gauge or to the load cell of a traction machine used as the gold standard (Instron Universal Testing Machine). Matrices were secured in a denture duplicate attached to the customized support, permitting reproducibility of their position on both pulling devices. Attachment retention in the axial direction was evaluated by measuring maximum dislodging force or peak load during five consecutive linear dislodgments of each attachment on both devices. After a wear simulation, retention was measured again at several time periods. The peak load measurements with the customized Imada device were similar to those obtained with the gold standard Instron machine. These findings suggest that the proposed portable device can provide accurate information on the retentive properties of attachment systems for removable dental prostheses. PMID:19912482

  8. Biomaterial aspects: A key factor in the longevity of implant overdenture attachment systems

    PubMed Central

    Daou, Elie E.

    2015-01-01

    Background: New attachment systems are released for mandibular two-implant overdentures often without evidence-based support. Biomaterial aspects are now the parameters considered when choosing the appropriate attachment. Studies regarding their properties remain scarce. Purpose: The purpose of this review was to help the clinician in selrcting the most adapted stud attachments according evidence-based dentistry. Materials and Methods: An electronic search was conducted using specific databases (PubMed, Medline, and Elsevier libraries). Peer-reviewed articles published in English up to July 2014 were identified. Emphasis was given on the biomaterial aspects and technical complications. No hand search was added. Results: The electronic search generated 115 full-text papers, of which 84 papers were included in the review. The majority were clinical and in vitro studies. Some review articles were also considered. Papers reported survival and failures of overdenture connection systems. Emphasis was laid on attachment deformation. Conclusion: Implant overdentures long-term follow-up studies may provide useful guidelines for the clinician in selecting the type of attachment system and overdenture design. Locator attachments are more and more used, with lesser complications reported. PMID:26312224

  9. Couple attachment and the quality of marital relationships: method and concept in the validation of the new couple attachment interview and coding system.

    PubMed

    Alexandrov, Elina O; Cowan, Philip A; Cowan, Carolyn Pape

    2005-06-01

    This study investigates links between adult attachment and marital quality in 73 married couples, using a new Couple Attachment Interview that was modeled after the Adult Attachment Interview but focuses on the relationship between the partners. A coding system (CAICS) comparing the interview protocol to prototypes for secure, dismissing, and preoccupied attachment styles yielded continuous ratings of all three styles, and categorical classifications of secure/insecure for each partner. The study found direct links between couple attachment and both self-reported and observed marital quality, with all three continuous scores contributing uniquely to the equations. In most cases, the continuous scores explained variation in marital quality after the categorical security scores were entered into the regressions, although categorical scores also contributed uniquely to the explanation of marital quality. Pairing of partners' scores explained significant variance in both self-reported and observed evaluations of the couple relationship. Security of couple attachment served as a mediator in the link between self-reported marital satisfaction and observed marital quality. The results illustrated the interconnection of methodological choices and theoretical advances in the study of attachment and couple relationship quality. PMID:16096190

  10. Examining antecedents of infant attachment security with mothers and fathers: An ecological systems perspective☆

    PubMed Central

    Lickenbrock, Diane M.; Braungart-Rieker, Julia M.

    2015-01-01

    Taking an ecological systems perspective, early parent–child relationships can be affected by interactions between systems where some are more proximally linked to the child than others. Socioeconomic status, a distal factor, is associated with social functioning during childhood, but research on its association with functioning during infancy, particularly attachment, is scant and inconsistent. Moreover, it is not clear how distal factors affect infant functioning. Other systems such as marital adjustment and parenting may moderate or mediate relations between distal factors and infant attachment. The current longitudinal study (n = 135) examined the role of various systems – parental resources, marital functioning, parental sensitivity and involvement – in early infancy (3-, 5-, 7-months) on infant–mother (12-months) and infant–father (14-months) attachment security. Findings supported moderating processes but in different ways for infant–mother versus infant–father dyads. Implications for future studies and interventions are discussed. PMID:25890261

  11. Design and performance of an atmospheric pressure inlet system for lithium ion attachment mass spectrometry.

    PubMed

    Selvin, P Christopher; Iwase, Keiichiro; Fujii, Toshihiro

    2002-05-01

    We designed a simple and efficient inlet system to act as an interface between samples at atmospheric pressure and the high vacuum inside a mass spectrometer. The newly designed stainless steel orifice leak sample inlet system is simple and rugged and fulfills all the basic requirements. With this inlet system coupled with a lithium ion attachment mass spectrometer, it is possible to detect any chemical species at atmospheric pressure, including radical intermediates, on a real-time basis. For illustrative purposes, the sampling efficiency of the inlet probe coupled with a lithium ion attachment mass spectrometer is discussed for laboratory air and polyethylene pyrolysis. PMID:12033306

  12. Evaluation of statistical models for predicting Escherichia coli particle attachment in fluvial systems.

    PubMed

    Piorkowski, Gregory; Jamieson, Rob; Bezanson, Greg; Hansen, Lisbeth Truelstrup; Yost, Chris

    2013-11-01

    Modeling surface water Escherichia coli fate and transport requires partitioning E. coli into particle-attached and unattached fractions. Attachment is often assumed to be a constant fraction or is estimated using simple linear models. The objectives of this study were to: (i) develop statistical models for predicting E. coli attachment and virulence marker presence in fluvial systems, and (ii) relate E. coli attachment to a variety of environmental parameters. Stream water samples (n = 60) were collected at four locations in a rural, mixed-use watershed between June and October 2012, with four storm events (>20 mm rainfall) being captured. The percentage of E. coli attached to particles (>5 μm) and the occurrences of virulence markers were modeled using water quality, particle concentration, particle size distribution, hydrology and land use factors as explanatory variables. Three types of statistical models appropriate for highly collinear, multidimensional data were compared: least angle shrinkage and selection operator (LASSO), classification and regression trees using the general, unbiased, interaction detection and estimation (GUIDE) algorithm, and multivariate adaptive regression splines (MARS). All models showed that E. coli particle attachment and the presence of E. coli virulence markers in the attached and unattached states were influenced by a combination of water quality, hydrology, land-use and particle properties. Model performance statistics indicate that MARS models outperform LASSO and GUIDE models for predicting E. coli particle attachment and virulence marker occurrence. Validating the MARS modeling approach in multiple watersheds may allow for the development of a parameterizing model to be included in watershed simulation models. PMID:24075474

  13. Equilibria and vibration of a buckled beam with attached masses or spring-mass systems

    NASA Astrophysics Data System (ADS)

    Plaut, Raymond H.; Virgin, Lawrence N.

    2016-09-01

    A buckled beam with immovable pinned ends is considered. Attached to the beam are either one concentrated mass, two concentrated masses, a spring-mass system (that could model a human, robot, or passive vibration absorber), or a horizontal rigid bar with two vertical end springs (a "bounce-pitch" system that could model an animal or a vehicle). In the theoretical analysis, the beam is modeled as an inextensible elastica. Equilibrium configurations are determined first. Then small free vibrations about equilibrium are examined, and the lowest frequencies and corresponding modes are computed. The effects of various parameters are investigated, such as the ratio of the span to the total arc length of the beam, the locations and weights of the attached masses and systems, and the stiffnesses of the springs. For the case of a single attached mass, experiments are conducted and the results are compared to the theoretical ones.

  14. 22 CFR 121.8 - End-items, components, accessories, attachments, parts, firmware, software and systems.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ..., parts, firmware, software and systems. 121.8 Section 121.8 Foreign Relations DEPARTMENT OF STATE...-items, components, accessories, attachments, parts, firmware, software and systems. (a) An end-item is.... Firmware includes but is not limited to circuits into which software has been programmed. (f)...

  15. 22 CFR 121.8 - End-items, components, accessories, attachments, parts, firmware, software and systems.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., parts, firmware, software and systems. 121.8 Section 121.8 Foreign Relations DEPARTMENT OF STATE...-items, components, accessories, attachments, parts, firmware, software and systems. (a) An end-item is.... Firmware includes but is not limited to circuits into which software has been programmed. (f)...

  16. 22 CFR 121.8 - End-items, components, accessories, attachments, parts, firmware, software and systems.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ..., parts, firmware, software and systems. 121.8 Section 121.8 Foreign Relations DEPARTMENT OF STATE...-items, components, accessories, attachments, parts, firmware, software and systems. (a) An end-item is.... Firmware includes but is not limited to circuits into which software has been programmed. (f)...

  17. 22 CFR 121.8 - End-items, components, accessories, attachments, parts, firmware, software and systems.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., parts, firmware, software and systems. 121.8 Section 121.8 Foreign Relations DEPARTMENT OF STATE...-items, components, accessories, attachments, parts, firmware, software and systems. (a) An end-item is.... Firmware includes but is not limited to circuits into which software has been programmed. (f)...

  18. 22 CFR 121.8 - End-items, components, accessories, attachments, parts, firmware, software, and systems.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ..., parts, firmware, software, and systems. 121.8 Section 121.8 Foreign Relations DEPARTMENT OF STATE...-items, components, accessories, attachments, parts, firmware, software, and systems. (a) An end-item is.... Firmware includes but is not limited to circuits into which software has been programmed. (f)...

  19. Therapy for Childhood Sexual Abuse Survivors using Attachment and Family Systems Theory Orientations

    PubMed Central

    Karakurt, Gunnur; Silver, Kristin E.

    2013-01-01

    The aim of this paper is to understand the effects of childhood sexual abuse on a survivor’s later life. For understanding and treating the emotional distress and interpersonal problems resulting from childhood sexual abuse, attachment theory provides a valuable framework. When this framework is combined with family systems theory, it can help therapists understand the family context where sexual abuse occurs and how this affects health and functioning throughout the lifespan. Case examples of female adult sexual abuse survivors are also explored, with insight from the intersection of systems and attachment theories. PMID:24443623

  20. Involvement of gecko SNAP25b in spinal cord regeneration by promoting outgrowth and elongation of neurites.

    PubMed

    Wang, Yingjie; Dong, Yingying; Song, Honghua; Liu, Yan; Liu, Mei; Yuan, Ying; Ding, Fei; Gu, Xiaosong; Wang, Yongjun

    2012-12-01

    SNARE complex mediates cellular membrane fusion events essential for neurotransmitter release and synaptogenesis. SNAP25, a member of the SNARE proteins, plays critical roles during the development of the central nervous system via regulation by alternative splicing and protein kinase phosphorylation. To date, little information is available regarding the protein in the spinal cord regeneration, especially for the postnatal highly expressed isoform SNAP25b. In the present study, we characterized gecko SNAP25b, which shared high identity with those of other vertebrates. Expression of gecko SNAP25b was temporally upregulated in both neurons of spinal cord and forming ependymal tube following tail amputation, coinciding with the occurrence of regenerate re-innervation. Overexpression of gecko wild type SNAP25b in the SH-SY5Y and undifferentiated PC12 cells promoted the elongation and outgrowth of neurites, while mutant constructs at Serine(187) resulted in differential effects for which S187A had a promoting role. Knockdown of endogenous SNAP25b affected the formation of neurites, which could be rescued by overexpression of SNAP25b. FM1-43 staining revealed that transfection of S187E mutant construct reduced the recruitment of vesicles. In addition, transfection of gecko SNAP25b in the astrocyte, which is absent from neuronal specific VAMP2, was capable of enhancing process elongation, indicating a potential for various alternative protein combinations. Taken together, our data suggest that gecko SNAP25b is involved in spinal cord regeneration by promoting outgrowth and elongation of neurites in a more extensive protein binding manner. PMID:23010346

  1. Neural Response during the Activation of the Attachment System in Patients with Borderline Personality Disorder: An fMRI Study

    PubMed Central

    Buchheim, Anna; Erk, Susanne; George, Carol; Kächele, Horst; Martius, Philipp; Pokorny, Dan; Spitzer, Manfred; Walter, Henrik

    2016-01-01

    Individuals with borderline personality disorder (BPD) are characterized by emotional instability, impaired emotion regulation and unresolved attachment patterns associated with abusive childhood experiences. We investigated the neural response during the activation of the attachment system in BPD patients compared to healthy controls using functional magnetic resonance imaging (fMRI). Eleven female patients with BPD without posttraumatic stress disorder (PTSD) and 17 healthy female controls matched for age and education were telling stories in the scanner in response to the Adult Attachment Projective Picture System (AAP), an eight-picture set assessment of adult attachment. The picture set includes theoretically-derived attachment scenes, such as separation, death, threat and potential abuse. The picture presentation order is designed to gradually increase the activation of the attachment system. Each picture stimulus was presented for 2 min. Analyses examine group differences in attachment classifications and neural activation patterns over the course of the task. Unresolved attachment was associated with increasing amygdala activation over the course of the attachment task in patients as well as controls. Unresolved controls, but not patients, showed activation in the right dorsolateral prefrontal cortex (DLPFC) and the rostral cingulate zone (RCZ). We interpret this as a neural signature of BPD patients’ inability to exert top-down control under conditions of attachment distress. These findings point to possible neural mechanisms for underlying affective dysregulation in BPD in the context of attachment trauma and fear. PMID:27531977

  2. Neural Response during the Activation of the Attachment System in Patients with Borderline Personality Disorder: An fMRI Study.

    PubMed

    Buchheim, Anna; Erk, Susanne; George, Carol; Kächele, Horst; Martius, Philipp; Pokorny, Dan; Spitzer, Manfred; Walter, Henrik

    2016-01-01

    Individuals with borderline personality disorder (BPD) are characterized by emotional instability, impaired emotion regulation and unresolved attachment patterns associated with abusive childhood experiences. We investigated the neural response during the activation of the attachment system in BPD patients compared to healthy controls using functional magnetic resonance imaging (fMRI). Eleven female patients with BPD without posttraumatic stress disorder (PTSD) and 17 healthy female controls matched for age and education were telling stories in the scanner in response to the Adult Attachment Projective Picture System (AAP), an eight-picture set assessment of adult attachment. The picture set includes theoretically-derived attachment scenes, such as separation, death, threat and potential abuse. The picture presentation order is designed to gradually increase the activation of the attachment system. Each picture stimulus was presented for 2 min. Analyses examine group differences in attachment classifications and neural activation patterns over the course of the task. Unresolved attachment was associated with increasing amygdala activation over the course of the attachment task in patients as well as controls. Unresolved controls, but not patients, showed activation in the right dorsolateral prefrontal cortex (DLPFC) and the rostral cingulate zone (RCZ). We interpret this as a neural signature of BPD patients' inability to exert top-down control under conditions of attachment distress. These findings point to possible neural mechanisms for underlying affective dysregulation in BPD in the context of attachment trauma and fear. PMID:27531977

  3. Mechanical work as a determinant of prey-handling behavior in the tokay gecko (Gekko gecko).

    PubMed

    Andrews, C; Bertram, J E

    1997-01-01

    In this study an in vitro analysis of the force and mechanical work required to bite prey items of different size and physical character is combined with an in vivo analysis of prey-handling behavior in the tokay gecko (Gekko gecko). The force required to bite and the work of biting increase with prey size, but the rate of increase is prey specific, with crickets (Acheta domestica) requiring substantially more force and work per bite than larvae (Galleria mellonella and Manduca sexta) for all but the smallest prey. Prey-handling behavior is also prey specific. Geckos exert more bites per feeding event on small crickets than on small insect larvae, but the number of bites increases faster with prey mass for larvae than for crickets. Combination of the in vitro mechanical measurements with the in vivo behavior analysis allows the calculation of total mechanical work per feeding event and indicates that total work increases with prey size but that the difference between prey types is far less than predicted from the differences in structural properties of the prey. This occurs because the number of bites and work per bite relationships tend to cancel the differences in the total work necessary to process each prey type. Thus, when considering the effect of prey size, a 13-fold greater rate of increase in bite force and an 18-fold greater rate of increase of work per bit for crickets over larvae was partially compensated for by a threefold increase in the number of bites used on larvae relative to crickets. These results can be interpreted in two ways. The effect of mechanical work in feeding behavior suggests that the energetics of jaw adductor musculature could play a greater role in governing the feeding behavior of this lizard than has previously been expected. Alternatively, the scaling of work in feeding over a range of prey sizes suggests distinct differences in the geometric features of the prey that determine how they are processed. PMID:9231392

  4. Introduction to the adhesive bonding session. [foam system for attaching thermal insulation on space shuttle

    NASA Technical Reports Server (NTRS)

    Mccarty, J. E.

    1972-01-01

    Space shuttle unique requirements call for the development of a specific adhesive system to reliable attach reusable surface insulation. A low density foam system has been developed that provides strain isolation from the support structure and remains structurally stable in space shuttle thermal environment. Surface preparation and its stabilization by an adhesive primer system are the most important factors in preventing corrosion from reducing the reliability and durability of the adhesive bonding component.

  5. Sticky gecko feet: the role of temperature and humidity.

    PubMed

    Niewiarowski, Peter H; Lopez, Stephanie; Ge, Liehui; Hagan, Emily; Dhinojwala, Ali

    2008-01-01

    Gecko adhesion is expected to be temperature insensitive over the range of temperatures typically experienced by geckos. Previous work is limited and equivocal on whether this expectation holds. We tested the temperature dependence of adhesion in Tokay and Day geckos and found that clinging ability at 12 degrees C was nearly double the clinging ability at 32 degrees C. However, rather than confirming a simple temperature effect, our data reveal a complex interaction between temperature and humidity that can drive differences in adhesion by as much as two-fold. Our findings have important implications for inferences about the mechanisms underlying the exceptional clinging capabilities of geckos, including whether performance of free-ranging animals is based solely on a dry adhesive model. An understanding of the relative contributions of van der Waals interactions and how humidity and temperature variation affects clinging capacities will be required to test hypotheses about the evolution of gecko toepads and is relevant to the design and manufacture of synthetic mimics. PMID:18478106

  6. Effects of surface wettability on gecko adhesion underwater.

    PubMed

    Peng, Z L; Wang, C; Chen, S H

    2014-10-01

    Recent experiments have shown that gecko adhesion underwater depends significantly on surface wettability. Theoretical models of a gecko seta adhering on different substrates are firstly established in order to disclose such an adhesion mechanism. The results show that the capillary force induced by nano-bubbles between gecko seta and the substrate is the mainly influencing factor. The capillary force exhibits an attractive feature between gecko setae and hydrophobic surfaces underwater. However, it is extremely weak or even repulsive on hydrophilic surfaces underwater. A self-similarly splitting model is further considered to simulate multiple gecko setae on substrates underwater. It is interesting to find that the total capillary force depends significantly on the number of nano-bubble bridges and wettability of substrates. The total force is attractive and increases monotonically with the increase of the splitting number on hydrophobic substrates underwater. However, it decreases drastically or even becomes repulsive on hydrophilic substrates underwater. The present result can not only give a reasonable explanation on the existing experimental observations but also be helpful for the design of novel biomimetic adhesives. PMID:25139291

  7. Ecological effects of the invasive giant madagascar day gecko on endemic mauritian geckos: applications of binomial-mixture and species distribution models.

    PubMed

    Buckland, Steeves; Cole, Nik C; Aguirre-Gutiérrez, Jesús; Gallagher, Laura E; Henshaw, Sion M; Besnard, Aurélien; Tucker, Rachel M; Bachraz, Vishnu; Ruhomaun, Kevin; Harris, Stephen

    2014-01-01

    The invasion of the giant Madagascar day gecko Phelsuma grandis has increased the threats to the four endemic Mauritian day geckos (Phelsuma spp.) that have survived on mainland Mauritius. We had two main aims: (i) to predict the spatial distribution and overlap of P. grandis and the endemic geckos at a landscape level; and (ii) to investigate the effects of P. grandis on the abundance and risks of extinction of the endemic geckos at a local scale. An ensemble forecasting approach was used to predict the spatial distribution and overlap of P. grandis and the endemic geckos. We used hierarchical binomial mixture models and repeated visual estimate surveys to calculate the abundance of the endemic geckos in sites with and without P. grandis. The predicted range of each species varied from 85 km2 to 376 km2. Sixty percent of the predicted range of P. grandis overlapped with the combined predicted ranges of the four endemic geckos; 15% of the combined predicted ranges of the four endemic geckos overlapped with P. grandis. Levin's niche breadth varied from 0.140 to 0.652 between P. grandis and the four endemic geckos. The abundance of endemic geckos was 89% lower in sites with P. grandis compared to sites without P. grandis, and the endemic geckos had been extirpated at four of ten sites we surveyed with P. grandis. Species Distribution Modelling, together with the breadth metrics, predicted that P. grandis can partly share the equivalent niche with endemic species and survive in a range of environmental conditions. We provide strong evidence that smaller endemic geckos are unlikely to survive in sympatry with P. grandis. This is a cause of concern in both Mauritius and other countries with endemic species of Phelsuma. PMID:24785293

  8. Ecological Effects of the Invasive Giant Madagascar Day Gecko on Endemic Mauritian Geckos: Applications of Binomial-Mixture and Species Distribution Models

    PubMed Central

    Buckland, Steeves; Cole, Nik C.; Aguirre-Gutiérrez, Jesús; Gallagher, Laura E.; Henshaw, Sion M.; Besnard, Aurélien; Tucker, Rachel M.; Bachraz, Vishnu; Ruhomaun, Kevin; Harris, Stephen

    2014-01-01

    The invasion of the giant Madagascar day gecko Phelsuma grandis has increased the threats to the four endemic Mauritian day geckos (Phelsuma spp.) that have survived on mainland Mauritius. We had two main aims: (i) to predict the spatial distribution and overlap of P. grandis and the endemic geckos at a landscape level; and (ii) to investigate the effects of P. grandis on the abundance and risks of extinction of the endemic geckos at a local scale. An ensemble forecasting approach was used to predict the spatial distribution and overlap of P. grandis and the endemic geckos. We used hierarchical binomial mixture models and repeated visual estimate surveys to calculate the abundance of the endemic geckos in sites with and without P. grandis. The predicted range of each species varied from 85 km2 to 376 km2. Sixty percent of the predicted range of P. grandis overlapped with the combined predicted ranges of the four endemic geckos; 15% of the combined predicted ranges of the four endemic geckos overlapped with P. grandis. Levin's niche breadth varied from 0.140 to 0.652 between P. grandis and the four endemic geckos. The abundance of endemic geckos was 89% lower in sites with P. grandis compared to sites without P. grandis, and the endemic geckos had been extirpated at four of ten sites we surveyed with P. grandis. Species Distribution Modelling, together with the breadth metrics, predicted that P. grandis can partly share the equivalent niche with endemic species and survive in a range of environmental conditions. We provide strong evidence that smaller endemic geckos are unlikely to survive in sympatry with P. grandis. This is a cause of concern in both Mauritius and other countries with endemic species of Phelsuma. PMID:24785293

  9. Breaking the Cycle: A Clinical Example of Disrupting an Insecure Attachment System.

    ERIC Educational Resources Information Center

    Pickover, Sheri

    2002-01-01

    Attachment theory has increasingly become a primary clinical focus as counselors cope with the repercussions of an insecure attachment style. Provides a brief overview of current attachment literature, an argument in favor of using attachment theory based on the possible consequences of insecure attachment, and an example of treating an…

  10. Cryptosporidium varanii infection in leopard geckos (Eublepharis macularius) in Argentina.

    PubMed

    Dellarupe, A; Unzaga, J M; Moré, G; Kienast, M; Larsen, A; Stiebel, C; Rambeaud, M; Venturini, M C

    2016-01-01

    Cryptosporidiosis is observed in reptiles with high morbidity and considerable mortality. The objective of this study was to achieve the molecular identification of Cryptosporidium spp. in pet leopard geckos (Eublepharis macularius) from a breeder colony in Buenos Aires, Argentina. Oocysts comparable to those of Cryptosporidium spp. were detected in three geckos with a history of diarrhea, anorexia and cachexia. Molecular identification methods confirmed the presence of Cryptosporidium varanii (syn. C. saurophilum). This agent was considered to be the primary cause of the observed clinical disease. This is the first description of C. varanii infection in pet reptiles in Argentina. PMID:27419102

  11. Biomechanics. Geckos climb by the hairs of their toes.

    PubMed

    Pennisi, E

    2000-06-01

    Biomechanists have uncovered the secret of how the gecko manages to run up walls and across ceilings: rows of tiny hairs with multiple split ends on the bottom of each toe pad. As they report in the 8 June issue of Nature, weak attractive forces between the 1000 or so split ends on each hair and the ceiling help the gecko grab even the smoothest surface. Armed with that knowledge, the researchers hope to design synthetic "footpads" to improve the maneuverability of robots and perhaps to design an entirely new type of adhesive. PMID:10877680

  12. Cryptosporidium varanii infection in leopard geckos (Eublepharis macularius) in Argentina

    PubMed Central

    Dellarupe, A.; Unzaga, J.M.; Moré, G.; Kienast, M.; Larsen, A.; Stiebel, C.; Rambeaud, M.; Venturini, M.C.

    2016-01-01

    Cryptosporidiosis is observed in reptiles with high morbidity and considerable mortality. The objective of this study was to achieve the molecular identification of Cryptosporidium spp. in pet leopard geckos (Eublepharis macularius) from a breeder colony in Buenos Aires, Argentina. Oocysts comparable to those of Cryptosporidium spp. were detected in three geckos with a history of diarrhea, anorexia and cachexia. Molecular identification methods confirmed the presence of Cryptosporidium varanii (syn. C. saurophilum). This agent was considered to be the primary cause of the observed clinical disease. This is the first description of C. varanii infection in pet reptiles in Argentina. PMID:27419102

  13. The carriage of antibiotic resistance by enteric bacteria from imported tokay geckos (Gekko gecko) destined for the pet trade.

    PubMed

    Casey, Christine L; Hernandez, Sonia M; Yabsley, Michael J; Smith, Katherine F; Sanchez, Susan

    2015-02-01

    The emergence of antibiotic-resistant bacteria is a growing public health concern and has serious implications for both human and veterinary medicine. The nature of the global economy encourages the movement of humans, livestock, produce, and wildlife, as well as their potentially antibiotic-resistant bacteria, across international borders. Humans and livestock can be reservoirs for antibiotic-resistant bacteria; however, little is known about the prevalence of antibiotic-resistant bacteria harbored by wildlife and, to our knowledge, limited data has been reported for wild-caught reptiles that were specifically collected for the pet trade. In the current study, we examined the antibiotic resistance of lactose-positive Enterobacteriaceae isolates from wild-caught Tokay geckos (Gekko gecko) imported from Indonesia for use in the pet trade. In addition, we proposed that the conditions under which wild animals are captured, transported, and handled might affect the shedding or fecal prevalence of antibiotic resistance. In particular we were interested in the effects of density; to address this, we experimentally modified densities of geckos after import and documented changes in antibiotic resistance patterns. The commensal enteric bacteria from Tokay geckos (G. gecko) imported for the pet trade displayed resistance against some antibiotics including: ampicillin, amoxicillin/clavulanic acid, cefoxitin, chloramphenicol, kanamycin and tetracycline. There was no significant difference in the prevalence of antibiotic-resistant bacteria after experimentally mimicking potentially stressful transportation conditions reptiles experience prior to purchase. There were, however, some interesting trends observed when comparing Tokay geckos housed individually and those housed in groups. Understanding the prevalence of antibiotic resistant commensal enteric flora from common pet reptiles is paramount because of the potential for humans exposed to these animals to acquire antibiotic

  14. Adhesive behaviour of gecko-inspired nanofibrillar arrays: combination of experiments and finite element modelling

    NASA Astrophysics Data System (ADS)

    Wang, Zheng-zhi; Xu, Yun; Gu, Ping

    2012-04-01

    A polypropylene nanofibrillar array was successfully fabricated by template-assisted nanofabrication strategy. Adhesion properties of this gecko-inspired structure were studied through two parallel and independent approaches: experiments and finite element simulations. Experimental results show relatively good normal adhesion, but accompanied by high preloads. The interfacial adhesion was modelled by effective spring elements with piecewise-linear constitution. The effective elasticity of the fibre-array system was originally calculated from our measured elasticity of single nanowire. Comparisons of the experimental and simulative results reveal quantitative agreement except for some explainable deviations, which suggests the potential applicability of the present models and applied theories.

  15. 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

  16. Exact free vibration of multi-step Timoshenko beam system with several attachments

    NASA Astrophysics Data System (ADS)

    Farghaly, S. H.; El-Sayed, T. A.

    2016-05-01

    This paper deals with the analysis of the natural frequencies, mode shapes of an axially loaded multi-step Timoshenko beam combined system carrying several attachments. The influence of system design and the proposed sub-system non-dimensional parameters on the combined system characteristics are the major part of this investigation. The effect of material properties, rotary inertia and shear deformation of the beam system for each span are included. The end masses are elastically supported against rotation and translation at an offset point from the point of attachment. A sub-system having two degrees of freedom is located at the beam ends and at any of the intermediate stations and acts as a support and/or a suspension. The boundary conditions of the ordinary differential equation governing the lateral deflections and slope due to bending of the beam system including the shear force term, due to the sub-system, have been formulated. Exact global coefficient matrices for the combined modal frequencies, the modal shape and for the discrete sub-system have been derived. Based on these formulae, detailed parametric studies of the combined system are carried out. The applied mathematical model is valid for wide range of applications especially in mechanical, naval and structural engineering fields.

  17. Powered orthosis and attachable power-assist device with Hydraulic Bilateral Servo System.

    PubMed

    Ohnishi, Kengo; Saito, Yukio; Oshima, Toru; Higashihara, Takanori

    2013-01-01

    This paper discusses the developments and control strategies of exoskeleton-type robot systems for the application of an upper limb powered orthosis and an attachable power-assist device for care-givers. Hydraulic Bilateral Servo System, which consist of a computer controlled motor, parallel connected hydraulic actuators, position sensors, and pressure sensors, are installed in the system to derive the joint motion of the exoskeleton arm. The types of hydraulic component structure and the control strategy are discussed in relation to the design philosophy and target joints motions. PMID:24110321

  18. Hitchhiker-G: A new carrier system for attached shuttle payloads

    NASA Technical Reports Server (NTRS)

    Goldsmith, T. C.

    1987-01-01

    A new carrier system has been developed for economical and quick response flight of small attached payloads on the space shuttle. Hitchhiker-G can accommodate up to 750 lb. of customer payloads in canisters or mounted to an exposed plate. The carrier connects to the orbiter's electrical systems and provides up to six customers with standard electrical services including power, real time telemetry, and commands. A transparent data and command system concept is employed to allow the customer to easily use his own ground support equipment and personnel to control his payload during integration and flight operations. The first Hitchhiker-G was successfully flown in January 1986 on STS 61C.

  19. System and method for changing a glove attached to a glove box

    DOEpatents

    Aluisi, Alan

    2001-01-01

    A system for changing the gloves of a glove box. The system requires the use of a new glove and a glove change ring to form a temporary secondary barrier to the exchange of atmospheres between the inner glove box and the room in which the glove box is operated. The system describes specific means for disengaging a used glove from the glove box port. The means for disengaging the used glove include use of a glove change hook and use of a glove with an attached tab for use in removal. A method for changing the gloves of a glove box is also described.

  20. Arboreal Day Geckos (Phelsuma madagascariensis) Differentially Modulate Fore- and Hind Limb Kinematics in Response to Changes in Habitat Structure.

    PubMed

    Zhuang, Mingna V; Higham, Timothy E

    2016-01-01

    By using adhesion, geckos can move through incredibly challenging habitats. However, continually changing terrain may necessitate modulation of the adhesive apparatus in order to maximize its effectiveness over a range of challenges. Behaviorally modulating how the adhesive system is applied can occur by altering the alignment of the foot relative to the long axis of the body and/or the angles between the digits (interdigital angle). Given the directionality of the adhesive system, geckos likely vary the application of the system via these mechanisms as they run. We quantified 3D movements (using high-speed video) of the day gecko, Phelsuma madagascariensis, running on a range of ecologically relevant inclines (0°, 45°, 90°) and perch diameters (1.5 cm, 10 cm and broad). We measured the instantaneous sum of interdigital angles and foot alignment relative to the body, as well as other kinematic variables, throughout each stride and across treatments. Modulation of foot alignment at 45° and 90° was similar between the forelimb and hind limb, but differed at 0°, suggesting that P. madagascariensis is able to exert an adhesive force using multiple strategies. Both the sum of interdigital angles and alignment in the fore- and hind foot were modulated. Differences in modulation between the limbs are likely related to the underlying morphology. The modulation of interdigital angle and foot alignment suggests that aspects other than the mechanism of adhesion, such as joint morphology, are important for arboreal movement in geckos. Our study of foot usage in arboreal locomotion reveals patterns that may be widespread across pad-bearing lizards. In addition to understanding the constraints exerted by the adhesive apparatus, we highlight how biomechanical traits may respond to the evolution of novel adaptations and morphologies. PMID:27145027

  1. Arboreal Day Geckos (Phelsuma madagascariensis) Differentially Modulate Fore- and Hind Limb Kinematics in Response to Changes in Habitat Structure

    PubMed Central

    Zhuang, Mingna V.; Higham, Timothy E.

    2016-01-01

    By using adhesion, geckos can move through incredibly challenging habitats. However, continually changing terrain may necessitate modulation of the adhesive apparatus in order to maximize its effectiveness over a range of challenges. Behaviorally modulating how the adhesive system is applied can occur by altering the alignment of the foot relative to the long axis of the body and/or the angles between the digits (interdigital angle). Given the directionality of the adhesive system, geckos likely vary the application of the system via these mechanisms as they run. We quantified 3D movements (using high-speed video) of the day gecko, Phelsuma madagascariensis, running on a range of ecologically relevant inclines (0°, 45°, 90°) and perch diameters (1.5 cm, 10 cm and broad). We measured the instantaneous sum of interdigital angles and foot alignment relative to the body, as well as other kinematic variables, throughout each stride and across treatments. Modulation of foot alignment at 45° and 90° was similar between the forelimb and hind limb, but differed at 0°, suggesting that P. madagascariensis is able to exert an adhesive force using multiple strategies. Both the sum of interdigital angles and alignment in the fore- and hind foot were modulated. Differences in modulation between the limbs are likely related to the underlying morphology. The modulation of interdigital angle and foot alignment suggests that aspects other than the mechanism of adhesion, such as joint morphology, are important for arboreal movement in geckos. Our study of foot usage in arboreal locomotion reveals patterns that may be widespread across pad-bearing lizards. In addition to understanding the constraints exerted by the adhesive apparatus, we highlight how biomechanical traits may respond to the evolution of novel adaptations and morphologies. PMID:27145027

  2. Implant-supported overdenture with prefabricated bar attachment system in mandibular edentulous patient

    PubMed Central

    Ha, Seung-Ryong; Song, Seung-Il; Hong, Seong-Tae; Kim, Gy-Young

    2012-01-01

    Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar® is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar® was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar® system in a mandibular edentulous patient. PMID:23236580

  3. Finite element analysis to compare complete denture and implant-retained overdentures with different attachment systems.

    PubMed

    Barão, Valentim Adelino Ricardo; Assunção, Wirley Gonçalves; Tabata, Lucas Fernando; Delben, Juliana Aparecida; Gomes, Erica Alves; de Sousa, Edson Antonio Capello; Rocha, Eduardo Passos

    2009-07-01

    This finite element analysis compared stress distribution on complete dentures and implant-retained overdentures with different attachment systems. Four models of edentulous mandible were constructed: group A (control), complete denture; group B, overdenture retained by 2 splinted implants with bar-clip system; group C, overdenture retained by 2 unsplinted implants with o'ring system; and group D, overdenture retained by 2 splinted implants with bar-clip and 2 distally placed o'ring system. Evaluation was performed on Ansys software, with 100-N vertical load applied on central incisive teeth. The lowest maximum general stress value (in megapascal) was observed in group A (64.305) followed by groups C (119.006), D (258.650), and B (349.873). The same trend occurred in supporting tissues with the highest stress value for cortical bone. Unsplinted implants associated with the o'ring attachment system showed the lowest maximum stress values among all overdenture groups. Furthermore, o'ring system also improved stress distribution when associated with bar-clip system. PMID:19553853

  4. Adhesive interactions of geckos with wet and dry fluoropolymer substrates

    PubMed Central

    Stark, Alyssa Y.; Dryden, Daniel M.; Olderman, Jeffrey; Peterson, Kelly A.; Niewiarowski, Peter H.; French, Roger H.; Dhinojwala, Ali

    2015-01-01

    Fluorinated substrates like Teflon® (poly(tetrafluoroethylene); PTFE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on PTFE. Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor–Winterton approximation and the Young–Dupré equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air. PMID:26109635

  5. Adhesive interactions of geckos with wet and dry fluoropolymer substrates.

    PubMed

    Stark, Alyssa Y; Dryden, Daniel M; Olderman, Jeffrey; Peterson, Kelly A; Niewiarowski, Peter H; French, Roger H; Dhinojwala, Ali

    2015-07-01

    Fluorinated substrates like Teflon® (poly(tetrafluoroethylene); PTFE) are well known for their role in creating non-stick surfaces. We showed previously that even geckos, which can stick to most surfaces under a wide variety of conditions, slip on PTFE. Surprisingly, however, geckos can stick reasonably well to PTFE if it is wet. In an effort to explain this effect, we have turned our attention to the role of substrate surface energy and roughness when shear adhesion occurs in media other than air. In this study, we removed the roughness component inherent to commercially available PTFE and tested geckos on relatively smooth wet and dry fluoropolymer substrates. We found that roughness had very little effect on shear adhesion in air or in water and that the level of fluorination was most important for shear adhesion, particularly in air. Surface energy calculations of the two fluorinated substrates and one control substrate using the Tabor-Winterton approximation and the Young-Dupré equation were used to determine the interfacial energy of the substrates. Using these interfacial energies we estimated the ratio of wet and dry normal adhesion for geckos clinging to the three substrates. Consistent with the results for rough PTFE, our predictions show a qualitative trend in shear adhesion based on fluorination, and the quantitative experimental differences highlight the unusually low shear adhesion of geckos on dry smooth fluorinated substrates, which is not captured by surface energy calculations. Our work has implications for bioinspired design of synthetics that can preferentially stick in water but not in air. PMID:26109635

  6. A performance evaluation of three membrane bioreactor systems: aerobic, anaerobic, and attached-growth.

    PubMed

    Achilli, A; Marchand, E A; Childress, A E

    2011-01-01

    Water sustainability is essential for meeting human needs for drinking water and sanitation in both developing and developed countries. Reuse, decentralization, and low energy consumption are key objectives to achieve sustainability in wastewater treatment. Consideration of these objectives has led to the development of new and tailored technologies in order to balance societal needs with the protection of natural systems. Membrane bioreactors (MBRs) are one such technology. In this investigation, a comparison of MBR performance is presented. Laboratory-scale submerged aerobic MBR (AMBR), anaerobic MBR (AnMBR), and attached-growth aerobic MBR (AtMBR) systems were evaluated for treating domestic wastewater under the same operating conditions. Long-term chemical oxygen demand (COD) and total organic carbon (TOC) monitoring showed greater than 80% removal in the three systems. The AnMBR system required three months of acclimation prior to steady operation, compared to one month for the aerobic systems. The AnMBR system exhibited a constant mixed liquor suspended solids concentration at an infinite solids retention time (i.e. no solids wasting), while the aerobic MBR systems produced approximately 0.25 g of biomass per gram of COD removed. This suggests a more economical solids management associated with the AnMBR system. Critical flux experiments were performed to evaluate fouling potential of the MBR systems. Results showed similar critical flux values between the AMBR and the AnMBR systems, while the AtMBR system showed relatively higher critical flux value. This result suggests a positive role of the attached-growth media in controlling membrane fouling in MBR systems. PMID:22049730

  7. Impact of Child Maltreatment on Attachment and Social Rank Systems: Introducing an Integrated Theory.

    PubMed

    Sloman, Leon; Taylor, Peter

    2016-04-01

    Child maltreatment is a prevalent societal problem that has been linked to a wide range of social, psychological, and emotional difficulties. Maltreatment impacts on two putative evolved psychobiological systems in particular, the attachment system and the social rank system. The maltreatment may disrupt the child's ability to form trusting and reassuring relationships and also creates a power imbalance where the child may feel powerless and ashamed. The aim of the current article is to outline an evolutionary theory for understanding the impact of child maltreatment, focusing on the interaction between the attachment and the social rank system. We provide a narrative review of the relevant literature relating to child maltreatment and these two theories. This research highlights how, in instances of maltreatment, these ordinarily adaptive systems may become maladaptive and contribute to psychopathology. We identify a number of novel hypotheses that can be drawn from this theory, providing a guide for future research. We finally explore how this theory provides a guide for the treatment of victims of child maltreatment. In conclusion, the integrated theory provides a framework for understanding and predicting the consequences of maltreatment, but further research is required to test several hypotheses made by this theory. PMID:25948552

  8. Adaptive simplification and the evolution of gecko locomotion: Morphological and biomechanical consequences of losing adhesion

    PubMed Central

    Higham, Timothy E.; Birn-Jeffery, Aleksandra V.; Collins, Clint E.; Hulsey, C. Darrin; Russell, Anthony P.

    2015-01-01

    Innovations permit the diversification of lineages, but they may also impose functional constraints on behaviors such as locomotion. Thus, it is not surprising that secondary simplification of novel locomotory traits has occurred several times among vertebrates and could potentially lead to exceptional divergence when constraints are relaxed. For example, the gecko adhesive system is a remarkable innovation that permits locomotion on surfaces unavailable to other animals, but has been lost or simplified in species that have reverted to a terrestrial lifestyle. We examined the functional and morphological consequences of this adaptive simplification in the Pachydactylus radiation of geckos, which exhibits multiple unambiguous losses or bouts of simplification of the adhesive system. We found that the rates of morphological and 3D locomotor kinematic evolution are elevated in those species that have simplified or lost adhesive capabilities. This finding suggests that the constraints associated with adhesion have been circumvented, permitting these species to either run faster or burrow. The association between a terrestrial lifestyle and the loss/reduction of adhesion suggests a direct link between morphology, biomechanics, and ecology. PMID:25548182

  9. Salmonella isolates from wild-caught Tokay geckos (Gekko gecko) imported to the U.S. from Indonesia.

    PubMed

    Smith, Katherine F; Yabsley, Michael J; Sanchez, Susan; Casey, Christine L; Behrens, Michael D; Hernandez, Sonia M

    2012-07-01

    Reptiles account for ∼10% of live animal shipments imported to the United States (U.S.), the majority of which are sold in the pet trade. Characterizing Salmonella shedding by imported reptiles is of value to public health, the pet industry, and veterinary medicine. Here we report results of a pilot survey of Salmonella serotypes isolated from wild-caught Indonesian Tokay geckos (Gekko gecko) imported to the U.S. Upon arrival, the geckos were individually housed until a fecal sample was acquired for Salmonella culture. The geckos were divided into three groups with variable numbers to investigate density effects. A second group was imported after 3 months and combined with the previous groups. A total of 88 Salmonella isolates were obtained from 110 geckos surveyed, representing 14 serogroups and 17 unique serotypes. Group prevalence ranged from 31-73%. A significant increase in prevalence and a change in serotype richness were detected between the time of import and 6 months later at necropsy. Six isolates (6.8%) expressed resistance to more than one antibiotic. All S. enterica subsp. enterica Adelaide isolates were resistant to nalidixic acid and sulfisoxazole, one S. enterica subsp. arizonae 61:k:z35 isolate was resistant to ampicillin and sulfisoxazole, and another 61:k:z35 isolate was resistant to streptomycin and sulfisoxazole. Forty-three additional isolates expressed resistance only to sulfisoxazole. The mechanisms for increased prevalence and apparent change in serotype richness are unknown, but could be due to stress associated with trade, transport, and captivity, increased transmission from unnaturally high densities, or contact with other species shedding Salmonella along the trade route. Future studies to differentiate the physical, social, and physiological effects of trade-related conditions on Salmonella shedding and transmission among reptiles will benefit the industry by identifying ways to reduce mortality, and safeguard the individuals

  10. An integrated wastewater treatment system using a BAS reactor with biomass attached to tubular supports.

    PubMed

    Luciano, Antonella; Viotti, Paolo; Mancini, Giuseppe; Torretta, Vincenzo

    2012-12-30

    This paper describes laboratory experiments aimed to develop a new wastewater treatment system as an alternative to a conventional domestic wastewater plant. A modified Biofilm Airlift Suspension reactor (BAS), with biomass attached to tubular supports, is proposed to address low organic loads (typical of domestic sewage) and low residence time (typical of compact reactors technology). Attached and suspended biomasses, coupled to the high dissolved oxygen (DO), allow high removal efficiencies (90% and 56% for COD and N-NH(4)(+) removal respectively) and high effluent quality to be reached. The experimental activity, divided into three parts, demonstrates the good efficiency of the process, and the reduction of the removal kinetics for the high operating pressure used in the technology. The occurrence of simultaneous nitrification-denitrification (SND) was also observed. When compared with the conventional BAS system, the present treatment shows comparable removal efficiencies and higher specific removal rates (80 mg COD/g VSS and 2.60 mg N-NH(4)(+)/g VSS). The experimental results were coupled with the development of a numerical model to aid in designing a full-scale treatment plant in Italy. PMID:23000503

  11. Modeling Stimulus-Frequency Otoacoustic Emissions in the Gecko

    NASA Astrophysics Data System (ADS)

    Bergevin, Christopher; Shera, Christopher A.

    2009-02-01

    Although lizards lack the basilar-membrane traveling waves evident in mammals, their ears produce stimulus-frequency otoacoustic emissions (SFOAEs) with latencies comparable to those measured in many mammals (1-2 ms or greater). To probe the origin of these relatively long OAE delays, we developed a model of SFOAE generation in the gecko. The model inner ear comprises a collection of linear, coupled oscillators (hair bundles and associated tectorium) whose effective damping manifests a small degree of irregularity. The model reproduces the major qualitative features of gecko SFOAEs, including their substantial delays. The SFOAE delays predicted by the model increase with the assumed sharpness of tuning, reflecting the build-up time associated with mechanical resonance.

  12. The evaluation of selected attachment systems for implant-retained overdenture based on retention characteristics analysis.

    PubMed

    Chladek, Grzegorz; Wrzuś-Wieliński, Marcin

    2010-01-01

    The results of mechanical characteristics of attachments used for retaining and stabilizing overdenture have been analysed. Two commercially used attachments (a ball attachment and a bar attachment) and elastic frictional attachments designed by the research team with Professor Chladek as the leader have been investigated. The diagrams of force-displacement characteristics have been registered. Retention forces (F(R)) have been determined and total work (W(T)) disconnecting the attachments has been calculated on the basis of these diagrams. The analysis of total work corresponding to different types of attachments made it possible to distinguish some characteristic areas which illustrate specific features of particular designs. It has been revealed that determining the retention force allows us to compare only the attachments which work on similar bases. In order to conduct a purely objective comparison of the efficiency of different designs, it is necessary to analyze complete force-displacement characteristics as well as to determine on this basis the subsequent phases of separating the parts of attachments and to find the value of the work which in fact determines their quality. The comparison of selected commercially used designs and the presented elastic frictional attachments (taking into account the criterion of work) gives clear evidence that the introduced design of attachment enables us to create very good conditions of retaining overdenture. PMID:21247057

  13. Photoelastic analysis of implant-retained and conventional obturator prostheses with different attachment systems and soft relining.

    PubMed

    do Prado Ribeiro, Paula; Goiato, Marcelo Coelho; Pellizzer, Eduardo Pizza; Pesqueira, Aldiéris Alves; Haddad, Marcela Filiè; de Carvalho Dekon, Stefan Fiuza; dos Santos, Daniela Micheline

    2011-05-01

    Complete and partial loss of maxillary bone may jeopardize oral physiology and generate complications as oral-sinus-nasal communication. Palatal obturator prostheses are a treatment alternative for rehabilitation of these patients. The aim of this study was to assess stress distribution, through photoelasticity, on palatal obturator prostheses associated with different attachment systems (o'ring, bar clip, and o'ring/bar clip) of implants and submitted to relining. Two photoelastic models were fabricated according to an experimental maxillary model with oral-sinus-nasal communication. One model did not present implants, whereas the other included 2 implants with 13.0 mm in length in the left ridge. Four colorless maxillary obturator prostheses were fabricated and relined with soft silicone. One of these prostheses presented no attachment system, whereas the remaining prostheses included attachment systems adapted to the implants. The assembly (model/attachment system/prosthesis) was positioned in a circular polariscope during loading with 100 N at 10 mm/s. The results were based on observation during the experiment and photographic records of stress on the photoelastic model. The bar clip system exhibited the highest stress concentration followed by o'ring/bar clip and o'ring systems. The attachment systems presented different stress distribution with greater concentration surrounding the implants and homogenous stress distribution on the photoelastic model without implants. The highest concentration of fringes occurred, in ascending order, with o'ring, o'ring/bar clip, and bar clip systems. PMID:21558947

  14. Effects of humidity on the mechanical properties of gecko setae.

    PubMed

    Prowse, Michael S; Wilkinson, Matt; Puthoff, Jonathan B; Mayer, George; Autumn, Kellar

    2011-02-01

    We tested the hypothesis that an increase in relative humidity (RH) causes changes in the mechanical properties of the keratin of adhesive gecko foot hairs (setae). We measured the effect of RH on the tensile deformation properties, fracture, and dynamic mechanical response of single isolated tokay gecko setae and strips of the smooth lamellar epidermal layer. The mechanical properties of gecko setae were strongly affected by RH. The complex elastic modulus (measured at 5 Hz) of a single seta at 80% RH was 1.2 GPa, only 39% of the value when dry. An increase in RH reduced the stiffness and increased the strain to failure. The loss tangent increased significantly with humidity, suggesting that water absorption produces a transition to a more viscous type of deformation. The influence of RH on the properties of the smooth epidermal layer was comparable with that of isolated seta, with the exception of stress at rupture. These values were two to four times greater for the setae than for the smooth layer. The changes in mechanical properties of setal keratin were consistent with previously reported increases in contact forces, supporting the hypothesis that an increase in RH softens setal keratin, which increases adhesion and friction. PMID:20920615

  15. Cohesion-decohesion asymmetry in geckos

    NASA Astrophysics Data System (ADS)

    Puglisi, G.; Truskinovsky, L.

    2013-03-01

    Lizards and insects can strongly attach to walls and then detach applying negligible additional forces. We propose a simple mechanical model of this phenomenon which implies active muscle control. We show that the detachment force may depend not only on the properties of the adhesive units, but also on the elastic interaction among these units. By regulating the scale of such cooperative interaction, the organism can actively switch between two modes of adhesion: delocalized (pull off) and localized (peeling).

  16. Nutritional degenerative myopathy in a population of captive bred Uroplatus phantasticus (satanic leaf-tailed geckoes).

    PubMed

    Les Gabor, J

    2005-01-01

    Severe generalized degenerative myopathy was diagnosed in a population of captive bred satanic leaf-tailed geckoes (Uroplatus phantasticus). The diagnosis was based on characteristic histological changes and response to dietary therapy. This is the first reported case of nutritional myopathy in the satanic leaf-tailed gecko. PMID:15690956

  17. Self-Cleaning Synthetic Adhesive Surfaces Mimicking Tokay Geckos.

    SciTech Connect

    Branson, Eric D.; Singh, Seema; Burckel, David Bruce; Fan, Hongyou; Houston, Jack E.; Brinker, C. Jeffrey; Johnson, Patrick

    2006-11-01

    A gecko's extraordinary ability to suspend itself from walls and ceilings of varied surface roughness has interested humans for hundreds of years. Many theories and possible explanations describing this phenomenon have been proposed including sticky secretions, microsuckers, and electrostatic forces; however, today it is widely accepted that van der Waals forces play the most important role in this type of dry adhesion. Inarguably, the vital feature that allows a gecko's suspension is the presence of billions 3 of tiny hairs on the pad of its foot called spatula. These features are small enough to reach within van der Waals distances of any surface (spatula radius ~100 nm); thus, the combined effect of billions of van der Waals interactions is more than sufficient to hold a gecko's weight to surfaces such as smooth ceilings or wet glass. Two lithographic approaches were used to make hierarchal structures with dimensions similar to the gecko foot dimensions noted above. One approach combined photo-lithography with soft lithography (micro-molding). In this fabrication scheme the fiber feature size, defined by the alumina micromold was 0.2 um in diameter and 60 um in height. The second approach followed more conventional photolithography-based patterning. Patterned features with dimensions ~0.3 mm in diameter by 0.5 mm tall were produced. We used interfacial force microscopy employing a parabolic diamond tip with a diameter of 200 nm to measure the surface adhesion of these structures. The measured adhesive forces ranged from 0.3 uN - 0.6 uN, yielding an average bonding stress between 50 N/cm2 to 100 N/cm2. By comparison the reported literature value for the average stress of a Tokay gecko foot is 10 N/cm2. Acknowledgements This work was funded by Sandia National Laboratory's Laboratory Directed Research & Development program (LDRD). All coating processes were conducted in the cleanroom facility located at the University of New Mexico's Center for High Technology

  18. Nuclear reactor fuel assembly duct-tube-to-inlet-nozzle attachment system

    DOEpatents

    Christiansen, David W.; Smith, Bob G.

    1982-01-01

    A reusable system for removably attaching the lower end 21 of a nuclear reactor fuel assembly duct tube to an upper end 11 of a nuclear reactor fuel assembly inlet nozzle. The duct tube's lower end 21 has sides terminating in locking tabs 22 which end in inwardly-extending flanges 23. The flanges 23 engage recesses 13 in the top section 12 of the inlet nozzle's upper end 11. A retaining collar 30 slides over the inlet nozzle's upper end 11 to restrain the flanges 23 in the recesses 13. A locking nut 40 has an inside threaded portion 41 which engages an outside threaded portion 15 of the inlet nozzle's upper end 11 to secure the retaining collar 30 against protrusions 24 on the duct tube's sides.

  19. Peer attachment formation by systemic redox regulation with social training after a sensitive period

    PubMed Central

    Koshiba, Mamiko; Karino, Genta; Senoo, Aya; Mimura, Koki; Shirakawa, Yuka; Fukushima, Yuta; Obara, Saya; Sekihara, Hitomi; Ozawa, Shimpei; Ikegami, Kentaro; Ueda, Toyotoshi; Yamanouchi, Hideo; Nakamura, Shun

    2013-01-01

    Attachment formation is the most pivotal factor for humans and animals in the growth and development of social relationships. However, the developmental processes of attachment formation mediated by sensory-motor, emotional, and cognitive integration remain obscure. Here we developed an animal model to understand the types of social interactions that lead to peer-social attachment formation. We found that the social interaction in a sensitive period was essential to stabilise or overwrite the initially imprinted peer affiliation state and that synchronised behaviour with others based on common motivations could be a driver of peer social attachment formation. Furthermore, feeding experience with supplementation of ubiquinol conferred peer social attachment formation even after the sensitive period. Surprisingly, the experience of feeding beyond the cage window was also effective to reduce the required amount ubiquinol, suggesting that peri-personal space modulation may affect socio-emotional cognition and there by lead to attachment formation. PMID:23974241

  20. Bond strengths of three resin systems used with brackets and embedded wire attachments.

    PubMed

    Schulz, R P; Mayhew, R B; Oesterle, L J; Pierson, W P

    1985-01-01

    Orthodontic wire bonded directly to teeth with a resin adhesive system has been used to establish anchor units for procedures in orthodontics as well as for splinting teeth in other disciplines. This procedure can save the cost and time of placing a bracket. In addition, several different resin systems have been used for this procedure as well as for placing brackets. The purpose of this study was to determine the strength of three adhesive systems used to bond orthodontic wires directly to teeth and to compare these values with those found for directly bonded orthodontic brackets. Equal sample sizes of brackets or wires were attached to 240 human teeth with either Concise, Miradept, or Endur in a standardized area of etched enamel. Shear and tensile strengths were measured at 30 minutes and at 48 hours. At 30 minutes brackets were significantly stronger than embedded wires, and Concise was significantly stronger than either of the other resins. However, all significant differences between any of the three resin systems using either bonded brackets or wires disappeared at 48 hours. Whether or not this initial strength difference is clinically significant remains speculative. PMID:3155593

  1. 24 CFR 350.11 - Notice of Attachment for Ginnie Mae Securities in Book-entry System.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Securities in Book-entry System. 350.11 Section 350.11 Housing and Urban Development Regulations Relating to... AND URBAN DEVELOPMENT BOOK-ENTRY PROCEDURES § 350.11 Notice of Attachment for Ginnie Mae Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by a creditor...

  2. 24 CFR 350.11 - Notice of Attachment for Ginnie Mae Securities in Book-entry System.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Securities in Book-entry System. 350.11 Section 350.11 Housing and Urban Development Regulations Relating to... AND URBAN DEVELOPMENT BOOK-ENTRY PROCEDURES § 350.11 Notice of Attachment for Ginnie Mae Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by a creditor...

  3. 24 CFR 350.11 - Notice of Attachment for Ginnie Mae Securities in Book-entry System.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Securities in Book-entry System. 350.11 Section 350.11 Housing and Urban Development Regulations Relating to... AND URBAN DEVELOPMENT BOOK-ENTRY PROCEDURES § 350.11 Notice of Attachment for Ginnie Mae Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by a creditor...

  4. Shape-memory alloy overload protection device for osseointegrated transfemoral implant prosthetic limb attachment system

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Shao, Fei; Hughes, Steven

    2002-11-01

    The osseointegrated trans-femoral implant system provides a direct anchoring technique to attach prosthetic limb. This technique was first introduced PI Brenmark in Sweden. The UK had the first clinical trial in 1997 and currently has 6 active limb wearers. The success of this procedure has the potential for improved gait function and mobility, increased employability and significant long-term improvements in the quality of life for above knee amputees. However, the significant load involved in the trans-femoral implant system has caused permanent deformation and/or fractures of the implant abutment in several occasions. To protect the implant system, the implant abutment in particularly, an overloading protection device was introduced. The device uses mechanical mechanism to release torsion overload on the abutment. However, the bending overload protection remains unsolved. To solve the problem, a new overload protection device was developed. This device uses SMA component for bending overload protection. In this paper, the results of non-linear finite element modelling of the SMA and steel (AISI 1040) components were presented. Experiments were also carried out using steel components to assess the design which is based on the non-linear property of the materials.

  5. Habitat structure determines competition intensity and invasion success in gecko lizards.

    PubMed

    Petren, K; Case, T J

    1998-09-29

    Species diversity is correlated with structural complexity in many animal communities; however, experimental tests of the mechanisms underlying this important relationship are rare, especially in terrestrial communities. We manipulated physical features of the habitat of gecko lizards and measured the effect on exploitation competition for insects. Increasing both the dispersion of food resources and microhabitat topography dramatically reduced interspecific competition. Adding topographic structure reduced the advantages of the larger, faster, invasive species. Interindividual spacing decreased, but intraspecific agonistic interference increased in the more territorial, resident species. Human structural alterations of the environment facilitate invasion and competitive displacement in this system. Physical microhabitat structure can potentially affect species interactions through a variety of complex mechanisms. PMID:9751735

  6. [Low-cost simple anchorage systems in the removable hybrid prosthesis. Locator Root Attachment and Würzburg post].

    PubMed

    Teubner, Eckart; Galindo, Martha L; Arnold, Dario; Marinello, Carlo P

    2009-01-01

    For a simple and provisional retention of a removable prosthesis, less expensive direct retainers are an option compared to indirect cast gold copings with attachment. The Dalbo-Rotex-retainer and the Ticap-system are clinically established. The Locator Root attachment and the Würzburger Stift were recently introduced. The Locator Root attachment uses a massive profiled cylindrical post as a radicular anchorage. The Würzburger Stift has a small endodontic part which is retained by four spreadable lamellae in a convergent cavity. They further differ in the design of the male and female part. Depending on the clinical situation these characteristics can offer benefits and disadvantages. Both systems are documented and their indication, advantages and restrictions are discussed with clinical relevance. PMID:20112639

  7. Reliability Improvement of Ground Fault Protection System Using an S-Type Horn Attachment Gap in AC Feeding System

    NASA Astrophysics Data System (ADS)

    Ajiki, Kohji; Morimoto, Hiroaki; Shimokawa, Fumiyuki; Sakai, Shinya; Sasaki, Kazuomi; Sato, Ryogo

    Contact wires used in feeding system for electric railroad are insulated by insulators. However, insulation of an insulator sometimes breaks down by surface dirt of an insulator and contact with a bird. The insulator breakdown derives a ground fault in feeding system. Ground fault will cause a human electric shock and a destruction of low voltage electric equipment. In order to prevent the damage by ground fault, an S-type horn has been applicable as equipped on insulators of negative feeder and protective wire until present. However, a concrete pole breaks down at the time of the ground fault because a spark-over voltage of the S-type horn is higher than a breakdown voltage of a concrete pole. Farther, the S-type horn installed in the steel tube pole does not discharge a case, because the earth resistance of a steel tube pole is very small. We assumed that we could solve these troubles by changing the power frequency spark-over voltage of the S-type horn from 12kV to 3kV. Accordingly, we developed an attachment gap that should be used to change the power frequency spark-over voltage of the S-type horn from 12kV to 3kV. The attachment gap consists of a gas gap arrester and a zinc oxide element. By the dynamic current test and the artificial ground fault test, we confirmed that the attachment gap in the S-type horn could prevent a trouble at the time of the ground fault.

  8. Biohydrogen production in the suspended and attached microbial growth systems from waste pastry hydrolysate.

    PubMed

    Han, Wei; Hu, Yunyi; Li, Shiyi; Li, Feifei; Tang, Junhong

    2016-10-01

    Waste pastry was hydrolyzed by glucoamylase and protease which were obtained from solid state fermentation of Aspergillus awamori and Aspergillus oryzae to produce waste pastry hydrolysate. Then, the effects of hydraulic retention times (HRTs) (4-12h) on hydrogen production rate (HPR) in the suspended microbial growth system (continuous stirred tank reactor, CSTR) and attached microbial growth system (continuous mixed immobilized sludge reactor, CMISR) from waste pastry hydrolysate were investigated. The maximum HPRs of CSTR (201.8mL/(h·L)) and CMISR (255.3mL/(h·L)) were obtained at HRT of 6h and 4h, respectively. The first-order reaction could be used to describe the enzymatic hydrolysis of waste pastry. The carbon content of the waste pastry remained 22.8% in the undigested waste pastry and consumed 77.2% for carbon dioxide and soluble microbial products. To our knowledge, this is the first study which reports biohydrogen production from waste pastry. PMID:27416509

  9. Condensation Risk of Mechanically Attached Roof Systems in Cold Climate Zones

    SciTech Connect

    Pallin, Simon B

    2013-01-01

    systems with thermoplastic membranes are prone to be more effected by interior air intrusion into the roof construction; both due to the wind induced pressure differences and due to the flexibility and elasticity of the membrane (Molleti, Baskaran, Kalinger, & Beaulieu, 2011). Depending on the air permeability of the material underneath the membrane, wind forces increase the risk of fluttering (also referred as billowing) of the thermoplastic membrane. Expectably, the wind induced pressure differences creates a convective air flow into the construction i.e. Page 2 air intrusion. If the conditions are right, moisture from the exchanging air may condensate on surfaces with a temperature below dew-point. The definite path of convective airflows through the building envelope is usually very difficult to determine and therefore simplified models (K nzel, Zirkelbach, & Scfafaczek, 2011) help to estimate an additional moisture loads as a result of the air intrusion. The wind uplifting pressure in combination with wind gusts are important factors for a fluttering roof. Unfortunately, the effect from a fluctuating wind is difficult to estimate as this is a highly dynamic phenomenon and existing standards (ASTM, 2011a) only take into account a steady state approach i.e. there is no guidance or regulations on how to estimate the air intrusion rate. Obviously, a more detailed knowledge on the hygrothermal performance of mechanically attached cool roof system is requested; in consideration to varying surface colors, roof air tightness, climate zones and indoor moisture supply.

  10. Effects of loading and size on maximum power output and gait characteristics in geckos.

    PubMed

    Irschick, Duncan J; Vanhooydonck, Bieke; Herrel, Anthony; Andronescu, Anemone

    2003-11-01

    Stride length, stride frequency and power output are all factors influencing locomotor performance. Here, we first test whether mass-specific power output limits climbing performance in two species of geckos (Hemidactylus garnoti and Gekko gecko) by adding external loads to their bodies. We then test whether body size has a negative effect on mass-specific power output. Finally, we test whether loading affects kinematics in both gecko species. Lizards were induced to run vertically on a smooth wooden surface with loads of 0-200% of body mass (BM) in H. garnoti and 0-100% BM in G. gecko. For each stride, we calculated angular and linear kinematics (e.g. trunk angle, stride length), performance (maximum speed) and mean mass-specific power output per stride. The addition of increasingly large loads caused an initial increase in maximum mass-specific power output in both species, but for H. garnoti, mass-specific power output remained constant at higher loads (150% and 200% BM), even though maximum velocity declined. This result, in combination with the fact that stride frequency showed no evidence of leveling off as speed increased in either species, suggests that power limits maximum speed. In addition, the large gecko (G. gecko) produced significantly less power than the smaller H. garnoti, despite the fact that both species ran at similar speeds. This difference disappeared, however, when we recalculated power output based on higher maximum speeds for unloaded G. gecko moving vertically obtained by other researchers. Finally, the addition of external loads did not affect speed modulation in either species: both G. gecko and H. garnoti increase speed primarily by increasing stride frequency, regardless of loading condition. For a given speed, both species take shorter but more strides with heavier loads, but for a given load, G. gecko attains similar speeds to H. garnoti by taking longer but fewer strides. PMID:14555734

  11. Development of a rotating algal biofilm growth system for attached microalgae growth with in situ biomass harvest.

    PubMed

    Gross, Martin; Henry, Wesley; Michael, Clayton; Wen, Zhiyou

    2013-12-01

    This work aimed to develop a rotating algal biofilm (RAB) cultivation system that can be widely adopted by microalgae producers for easy biomass harvest. Algal cells were grown on the surface of a material rotating between nutrient-rich liquid and CO2-rich gaseous phase. Scrapping biomass from the attached surface avoided the expensive harvest operations such as centrifugation. Among various attachment materials, cotton sheet resulted in best algal growth, durability, and cost effectiveness. A lab-scale RAB system was further optimized with harvest frequency, rotation speed, and CO2 levels. The algal biomass from the RAB system had a similar water content as that in centrifuged biomass. An open pond raceway retrofitted with a pilot-scale RAB system resulted in a much higher biomass productivity when compared to a control open pond. Collectively, the research shows that the RAB system is an efficient algal culture system for easy biomass harvest with enhanced biomass productivity. PMID:24161650

  12. A quality-of-life comparison between self-aligning and ball attachment systems for 2-implant-retained mandibular overdentures.

    PubMed

    Bilhan, Hakan; Geckili, Onur; Sulun, Tonguc; Bilgin, Tayfun

    2011-03-01

    The aim of this study was to evaluate the self-aligning overdenture attachment system by comparing its oral health-related quality of life (OHRQL) with a traditionally used ball attachment system. In this randomized, within-subject crossover trial, 25 edentulous subjects each received 2 mandibular implants, and were then assigned to receive either self-aligning or traditional ball attachments. After 3 months, all subjects were switched to the second attachment type. The OHRQL was evaluated for both of the treatments using the short form of the Oral Health Impact Profile (OHIP-14). A subanalysis among subjects with below-average space available for attachment placement was also performed. Wilcoxon signed-rank test was used to compare differences between groups. Scores on the OHIP-14 physical disability domain were significantly better for the self-aligning attachment system (P  =  .049). Among subjects with below-average attachment space, functional limitation, psychological discomfort, physical disability, psychological disability, and total OHIP-14, scores were significantly better for the self-aligning attachment system (P  =  .041, P  =  .047, P  =  .048, P  =  .026, and P  =  .005, respectively). The self-aligning attachment system for 2-implant-retained mandibular overdentures is equal or superior to traditional ball attachments in all domains of the OHIP-14. PMID:20662674

  13. Comparative study of the fluid viscosity in tarsal hairy attachment systems of flies and beetles

    PubMed Central

    Peisker, Henrik; Heepe, Lars; Kovalev, Alexander E.; Gorb, Stanislav N.

    2014-01-01

    Wet adhesive systems of insects strongly rely for their function on the formation of capillary bridges with the substrate. Studies on the chemical composition and evaporation dynamics of tarsal secretions strongly suggest a difference in chemistry of secretion in beetles and flies, both possessing hairy attachment devices. This difference is assumed to influence the viscosity of the secretion. Here, we applied a microrheological technique, based on the immersion of nanometric beads in the collected tarsal footprints, to estimate secretion viscosity in a beetle (Coccinella septempunctata) and a fly (Calliphora vicina). Both species studied possess distinct differences in viscosity, the median of which was calculated as 21.8 and 10.9 mPa s, respectively. We further present an approximate theoretical model to calculate the contact formation time of spatula-like terminal contact elements using the viscosity data of the covering fluid. The estimated contact formation time is proportional to the tarsal secretion viscosity and to the square of the contact radius of the contact element. PMID:25142527

  14. Nuclear reactor fuel assembly duct-tube-to-handling-socket attachment system

    DOEpatents

    Christiansen, David W.; Smith, Bob G.

    1982-01-01

    A reusable system for removably attaching the upper end 10of a nuclear reactor duct tube to the lower end 30 of a nuclear reactor fuel assembly handling socket. A transition ring 20, fixed to the duct tube's upper end 10, has an interior-threaded section 22 with a first locking hole segment 24. An adaptor ring 40, fixed to the handling socket's lower end 30 has an outside-threaded section 42 with a second locking hole segment 44. The inside 22 and outside 42 threaded sections match and can be joined so that the first 24 and second 44 locking hole segments can be aligned to form a locking hole. A locking ring 50, with a locking pin 52, slides over the adaptor ring 40 so that the locking pin 52 fits in the locking hole. A swage lock 60 or a cantilever finger lock 70 is formed from the locking cup collar 26 to fit in a matching groove 54 or 56 in the locking ring 50 to prevent the locking ring's locking pin 52 from backing out of the locking hole.

  15. Attachment Disorganization.

    ERIC Educational Resources Information Center

    Solomon, Judith, Ed.; George, Carol, Ed.

    Disorganized attachment relationships were first formally identified on the basis of the anomalous behavior of some infants during laboratory separations and reunions with the parent. This book presents new research and theory on the topic of attachment disorganization, an area of investigation that is of increasing importance in the study of…

  16. Inhibition of gecko GSK-3β promotes elongation of neurites and oligodendrocyte processes but decreases the proliferation of blastemal cells.

    PubMed

    Wang, Yingjie; Gu, Qing; Dong, Yingying; Zhou, Weijuan; Song, Honghua; Liu, Yan; Liu, Mei; Yuan, Ying; Ding, Fei; Gu, Xiaosong; Wang, Yongjun

    2012-06-01

    GSK-3β signaling is involved in regulation of both neuronal and glial cell functions, and interference of the signaling affects central nervous system (CNS) development and regeneration. Thus, GSK-3β was proposed to be an important therapeutic target for promoting functional recovery of adult CNS injuries. To further clarify the regulatory function of the kinase on the CNS regeneration, we characterized gecko GSK-3β and determined the effects of GSK-3β inactivation on the neuronal and glial cell lines, as well as on the gecko tail (including spinal cord) regeneration. Gecko GSK-3β shares 91.7-96.7% identity with those of other vertebrates, and presented higher expression abundance in brain and spinal cord. The kinase strongly colocalized with the oligodendrocytes while less colocalized with neurons in the spinal cord. Phosphorylated GSK-3β (pGSK-3β) levels decreased gradually during the normally regenerating spinal cord ranging from L13 to the 6th caudal vertebra. Lithium injection increased the pGSK-3β levels of the corresponding spinal cord segments, and in vitro experiments on neurons and oligodendrocyte cell line revealed that the elevation of pGSK-3β promoted elongation of neurites and oligodendrocyte processes. In the normally regenerate tails, pGSK-3β kept stable in 2 weeks, whereas decreased at 4 weeks. Injection of lithium led to the elevation of pGSK-3β levels time-dependently, however destructed the regeneration of the tail including spinal cord. Bromodeoxyuridine (BrdU) staining demonstrated that inactivation of GSK-3β decreased the proliferation of blastemal cells. Our results suggested that species-specific regulation of GSK-3β was indispensable for the complete regeneration of CNS. PMID:22234988

  17. A new species of gecko (Squamata: Diplodactylidae: Strophurus) from north Queensland, Australia.

    PubMed

    Vanderduys, Eric

    2016-01-01

    A new species of diplodactylid gecko in the genus Strophurus Fitzinger, from north Queensland, Australia, is described herein as Strophurus congoo sp. nov. It is a small, pale grey to tan, unpatterned or faintly striped gecko, resembling the phasmid geckos in appearance, habitat and behaviour. However, within Strophurus it is not closely related to the phasmid geckos. It is distinguished from all other Strophurus by a combination of even scalation, dull colouration, small size and short tail length. It is only known to occur in a restricted area of the northern Great Dividing Range, within the Einasleigh Uplands bioregion, in a relatively infertile area of rolling, largely granitic hills, and is only known from spinifex (Triodia) hummock grasslands in open woodland. PMID:27395178

  18. Redesign of solid rocket booster/external tank attachment ring for the space transportation system

    NASA Technical Reports Server (NTRS)

    Mccomb, Harvey G., Jr. (Compiler)

    1987-01-01

    An improved design concept is presented for the Space Shuttle solid rocket booster (SRB)/external tank (ET) attachment ring structural component. This component picks up three struts which attach the aft end of each SRB to the ET. The concept is a partial ring with carefully tapered ends to distribute fastener loads safely into the SRB. Extensive design studies and analyses were performed to arrive at the concept. Experiments on structural elements were performed to determine material strength and stiffness characteristics. Materials and fabrication studies were conducted to determine acceptable tolerances for the design concept. An overview is provided of the work along with conclusions and major recommendations.

  19. Molecular characterization of the leopard gecko POMC gene and expressional change in the testis by acclimation to low temperature and with a short photoperiod.

    PubMed

    Endo, Daisuke; Park, Min Kyun

    2004-08-01

    The gene for proopiomelanocortin (POMC), a common precursor of malanotropins, corticotropin, and beta-endorphin, was isolated and analyzed in the squamata species, the leopard gecko, Eublepharis macularius. Leopard gecko POMC (lgPOMC) cDNA is composed of 1299bp, excluding the poly(A) tail, and encodes 270 amino acids. The deduced amino acid sequence showed the same structural organization as that of other species and displayed identity with those of other vertebrates: 68% with mud turtles, 57/57% with African clawed frog A/B, 53% with chickens, and 45% with mice. In a phylogenic tree, the lgPOMC clustered with the sequences of the mud turtle POMC and python POMC. The lgPOMC gene comprises three exons and two introns and this structure is consistent with humans, rats, mice, African clawed frog and zebrafish. RT-PCR analysis revealed that the lgPOMC mRNA was expressed only in the whole brain, pituitary, and gonads. To analyze in more detail, a competitive assay system to quantify the expression levels of POMC mRNA was established. We measured the POMC mRNA expression levels in the leopard gecko testes following transfer from a condition of 29 degrees C, 16L/8D to 18 degrees C, 10L/14D over 6 weeks. This 6-week acclimation increased the POMC mRNA expression levels significantly. This suggests that the leopard gecko POMC-derived peptides play a role in the mediation of the effect of environmental factors on reproduction. PMID:15242753

  20. Spindly attachments

    PubMed Central

    Çivril, Filiz; Musacchio, Andrea

    2008-01-01

    The attachment of chromosomes to spindle microtubules during mitosis is a delicate and intricate process on which eukaryotic cells critically depend to maintain their ploidy. In this issue of Genes & Development, Gassmann and colleagues (pp. 2385–2399 present an analysis of the recently discovered Spindly/SPDL-1 protein that casts new lights onto the attachment process and the way it relates to the control of cell cycle progression. PMID:18765786

  1. Attachment as an Organizational Construct

    ERIC Educational Resources Information Center

    Sroufe, L. Alan; Waters, Everett

    1977-01-01

    Discusses the conflict between situational influences and stable individual differences in attachment behavior and attempts to resolve this conflict by examining the functions, outcomes, and context sensitivity of attachment behavior and the underlying behavioral control systems that organize it. (JMB)

  2. Reverse adhesion of a gecko-inspired synthetic adhesive switched by an ion-exchange polymer-metal composite actuator.

    PubMed

    Guo, Dong-Jie; Liu, Rui; Cheng, Yu; Zhang, Hao; Zhou, Li-Ming; Fang, Shao-Ming; Elliott, Winston Howard; Tan, Wei

    2015-03-11

    Inspired by how geckos abduct, rotate, and adduct their setal foot toes to adhere to different surfaces, we have developed an artificial muscle material called ion-exchange polymer-metal composite (IPMC), which, as a synthetic adhesive, is capable of changing its adhesion properties. The synthetic adhesive was cast from a Si template through a sticky colloid precursor of poly(methylvinylsiloxane) (PMVS). The PMVS array of setal micropillars had a high density of pillars (3.8 × 10(3) pillars/mm(2)) with a mean diameter of 3 μm and a pore thickness of 10 μm. A graphene oxide monolayer containing Ag globular nanoparticles (GO/Ag NPs) with diameters of 5-30 nm was fabricated and doped in an ion-exchanging Nafion membrane to improve its carrier transfer, water-saving, and ion-exchange capabilities, which thus enhanced the electromechanical response of IPMC. After being attached to PMVS micropillars, IPMC was actuated by square wave inputs at 1.0, 1.5, or 2.0 V to bend back and forth, driving the micropillars to actively grip or release the surface. To determine the adhesion of the micropillars, the normal adsorption and desorption forces were measured as the IPMC drives the setal micropillars to grip and release, respectively. Adhesion results demonstrated that the normal adsorption forces were 5.54-, 14.20-, and 23.13-fold higher than the normal desorption forces under 1.0, 1.5, or 2.0 V, respectively. In addition, shear adhesion or friction increased by 98, 219, and 245%, respectively. Our new technique provides advanced design strategies for reversible gecko-inspired synthetic adhesives, which might be used for spiderman-like wall-climbing devices with unprecedented performance. PMID:25676143

  3. Ceramic to metal attachment system. [Ceramic electrode to metal conductor in MHD generator

    DOEpatents

    Marchant, D.D.

    1983-06-10

    A composition and method are described for attaching a ceramic electrode to a metal conductor. A layer of randomly interlocked metal fibers saturated with polyimide resin is sandwiched between the ceramic electrode and the metal conductor. The polyimide resin is then polymerized providing bonding.

  4. Changes in materials properties explain the effects of humidity on gecko adhesion.

    PubMed

    Puthoff, Jonathan B; Prowse, Michael S; Wilkinson, Matt; Autumn, Kellar

    2010-11-01

    Geckos owe their remarkable stickiness to millions of dry setae on their toes, and the mechanism of adhesion in gecko setae has been the topic of scientific scrutiny for over two centuries. Previously, we demonstrated that van der Waals forces are sufficient for strong adhesion and friction in gecko setae, and that water-based capillary adhesion is not required. However, recent studies demonstrated that adhesion increases with relative humidity (RH) and proposed that surface hydration and capillary water bridge formation is important or even necessary. In this study, we confirmed a significant effect of RH on gecko adhesion, but rejected the capillary adhesion hypothesis. While contact forces of isolated tokay gecko setal arrays increased with humidity, the increase was similar on hydrophobic and hydrophilic surfaces, inconsistent with a capillary mechanism. Contact forces increased with RH even at high shear rates, where capillary bridge formation is too slow to affect adhesion. How then can a humidity-related increase in adhesion and friction be explained? The effect of RH on the mechanical properties of setal β-keratin has escaped consideration until now. We discovered that an increase in RH softens setae and increases viscoelastic damping, which increases adhesion. Changes in setal materials properties, not capillary forces, fully explain humidity-enhanced adhesion, and van der Waals forces remain the only empirically supported mechanism of adhesion in geckos. PMID:20952618

  5. Gecko proteins induce the apoptosis of bladder cancer 5637 cells by inhibiting Akt and activating the intrinsic caspase cascade.

    PubMed

    Kim, Geun-Young; Park, Soon Yong; Jo, Ara; Kim, Mira; Leem, Sun-Hee; Jun, Woo-Jin; Shim, Sang In; Lee, Sang Chul; Chung, Jin Woong

    2015-09-01

    Gecko proteins have long been used as anti-tumor agents in oriental medicine, without any scientific background. Although anti-tumor effects of Gecko proteins on several cancers were recently reported, their effect on bladder cancer has not been investigated. Thus, we explored the anti-tumor effect of Gecko proteins and its cellular mechanisms in human bladder cancer 5637 cells. Gecko proteins significantly reduced the viability of 5637 cells without any cytotoxic effect on normal cells. These proteins increased the Annexin-V staining and the amount of condensed chromatin, demonstrating that the Gecko proteinsinduced cell death was caused by apoptosis. Gecko proteins suppressed Akt activation, and the overexpression of constitutively active form of myristoylated Akt prevented Gecko proteins-induced death of 5637 cells. Furthermore, Gecko proteins activated caspase 9 and caspase 3/7. Taken together, our data demonstrated that Gecko proteins suppressed the Akt pathway and activated the intrinsic caspase pathway, leading to the apoptosis of bladder cancer cells. [BMB Reports 2015; 48(9): 531-536]. PMID:26246284

  6. Direct evidence of phospholipids in gecko footprints and spatula–substrate contact interface detected using surface-sensitive spectroscopy

    PubMed Central

    Hsu, Ping Yuan; Ge, Liehui; Li, Xiaopeng; Stark, Alyssa Y.; Wesdemiotis, Chrys; Niewiarowski, Peter H.; Dhinojwala, Ali

    2012-01-01

    Observers ranging from Aristotle to young children have long marvelled at the ability of geckos to cling to walls and ceilings. Detailed studies have revealed that geckos are ‘sticky’ without the use of glue or suction devices. Instead, a gecko's stickiness derives from van der Waals interactions between proteinaceous hairs called setae and substrate. Here, we present surprising evidence that although geckos do not use glue, a residue is transferred on surfaces as they walk—geckos leave footprints. Using matrix-free nano-assisted laser desorption-ionization mass spectrometry, we identified the residue as phospholipids with phosphocholine head groups. Moreover, interface-sensitive sum-frequency generation spectroscopy revealed predominantly hydrophobic methyl and methylene groups and the complete absence of water at the contact interface between a gecko toe pad and the substrate. The presence of lipids has never been considered in current models of gecko adhesion. Our analysis of gecko footprints and the toe pad–substrate interface has significant consequences for models of gecko adhesion and by extension, the design of synthetic mimics. PMID:21865250

  7. Gecko inspired carbon nanotube based thermal gap pads

    NASA Astrophysics Data System (ADS)

    Sethi, Sunny; Dhinojwala, Ali

    2012-02-01

    Thermal management has become a critical factor in designing the next generation of microprocessors. The bottleneck in design of material for efficient heat transfer from electronic units to heat sinks is to enhance heat flow across interface between two dissimilar, rough surfaces. Carbon nanotubes (CNT) have been shown to be promising candidates for thermal transport. However, the heat transport across the interface continues to be a challenging hurdle. In the current work we designed free standing thermal pads based on gecko-inspired carbon nanotube adhesives. The pads were made of metallic carbon nanotubes and the structure was designed such that it would allow large area of intimate contact. We showed that these adhesive pads can be used as electrical and thermal interconnects.

  8. Slippery pores: anti-adhesive effect of nanoporous substrates on the beetle attachment system

    PubMed Central

    Gorb, E. V.; Hosoda, N.; Miksch, C.; Gorb, S. N.

    2010-01-01

    Traction experiments with adult seven-spotted ladybird beetles Coccinella septempunctata (L.) were carried out to study the influence of surface structure on insect attachment. Force measurements were performed with tethered walking insects, both males and females, on five different substrates: (i) smooth glass plate, (ii) smooth solid Al2O3 (sapphire) disc, and (iii–v) porous Al2O3 discs (anodisc membranes) with the same pore diameter but different porosity. The traction force of beetles ranged from 0.16 to 16.59 mN in males and from 0.32 to 8.99 mN in females. In both sexes, the highest force values were obtained on smooth solid surfaces, where males showed higher forces than females. On all three porous substrates, forces were significantly reduced in both males and females, and the only difference within these surfaces was obtained between membranes with the highest and lowest porosity. Males produced essentially lower forces than females on porous samples. The reduction in insect attachment on anodisc membranes may be explained by (i) possible absorption of the secretion fluid from insect adhesive pads by porous media and/or (ii) the effect of surface roughness. Differences in attachment between males and females were probably caused by the sexual dimorphism in the terminal structure of adhesive setae. PMID:20427333

  9. Slippery pores: anti-adhesive effect of nanoporous substrates on the beetle attachment system.

    PubMed

    Gorb, E V; Hosoda, N; Miksch, C; Gorb, S N

    2010-11-01

    Traction experiments with adult seven-spotted ladybird beetles Coccinella septempunctata (L.) were carried out to study the influence of surface structure on insect attachment. Force measurements were performed with tethered walking insects, both males and females, on five different substrates: (i) smooth glass plate, (ii) smooth solid Al(2)O(3) (sapphire) disc, and (iii-v) porous Al(2)O(3) discs (anodisc membranes) with the same pore diameter but different porosity. The traction force of beetles ranged from 0.16 to 16.59 mN in males and from 0.32 to 8.99 mN in females. In both sexes, the highest force values were obtained on smooth solid surfaces, where males showed higher forces than females. On all three porous substrates, forces were significantly reduced in both males and females, and the only difference within these surfaces was obtained between membranes with the highest and lowest porosity. Males produced essentially lower forces than females on porous samples. The reduction in insect attachment on anodisc membranes may be explained by (i) possible absorption of the secretion fluid from insect adhesive pads by porous media and/or (ii) the effect of surface roughness. Differences in attachment between males and females were probably caused by the sexual dimorphism in the terminal structure of adhesive setae. PMID:20427333

  10. The gecko visual pigment: a pH indicator with a salt effect.

    PubMed

    Crescitelli, F

    1981-12-01

    1. Unlike rhodopsin, the extracted 521-pigment of the Tokay gecko (Gekko gekko) is pH-sensitive and changes its spectral absorbance in the pH range of 4.5-7.3. The colour change is reversible and pH can be employed to adjust the spectral maximum anywhere between 490 nm and its native location at 521 nm.2. The hypsochromic shift with increasing acidity is opposite to that expected for the protonation of the Schiff base nitrogen and suggests an action on the secondary system of interacting charges that have long been postulated to adjust vertebrate visual pigment colour within the visible spectrum.3. Chloride ions modulate this pH effect in a systematic and significant manner. For the pigment extracted in the chloride-deficient state the colour change occurs in the pH range of 6.0-7.0, the midpoint being close to 6.5, suggesting the possible participation of the imidazole group of histidine as the functional moiety. With added NaCl the colour shifts to the region below pH 6.2.4. The modulating action of chloride is postulated to be a conformational change of the opsin leading to a shift of the secondary interacting site from one functional group to another or else to a change in pK of a single group due to the conformational alteration of the electrostatics of the system.5. At pH values between 7.5 and 9.0 a different mechanism becomes apparent. In this region a decrease occurs in the photopigment density as well as a shift in absorbance toward the blue. This alkaline effect is readily reversed either by adding NaCl or else by lowering the pH. Along with the other protective effects of chloride these ions serve to reduce or prevent this alkaline loss in density.6. Associated with this reversible photopigment loss is a reversible appearance of a product with a maximum at about 366 nm. The spectrum of this product is like that produced by the addition of 11-cis retinal to the extract. Acidification of the alkaline preparation leads to a restitution of the photopigment

  11. Physiological Status Drives Metabolic Rate in Mediterranean Geckos Infected with Pentastomes

    PubMed Central

    Caballero, Isabel C.; Sakla, Andrew J.; Detwiler, Jillian T.; Le Gall, Marion; Behmer, Spencer T.; Criscione, Charles D.

    2015-01-01

    Negative effects of parasites on their hosts are well documented, but the proximate mechanisms by which parasites reduce their host’s fitness are poorly understood. For example, it has been suggested that parasites might be energetically demanding. However, a recent meta-analysis suggests that they have statistically insignificant effects on host resting metabolic rate (RMR). It is possible, though, that energetic costs associated with parasites are only manifested during and/or following periods of activity. Here, we measured CO2 production (a surrogate for metabolism) in Mediterranean geckos (Hemidactylus turcicus) infected with a lung parasite, the pentastome Raillietiella indica, under two physiological conditions: rested and recently active. In rested geckos, there was a negative, but non-significant association between the number of pentastomes (i.e., infection intensity) and CO2 production. In recently active geckos (chased for 3 minutes), we recorded CO2 production from its maximum value until it declined to a stationary phase. We analyzed this decline as a 3 phase function (initial decline, secondary decline, stationary). Geckos that were recently active showed, in the secondary phase, a significant decrease in CO2 production as pentastome intensity increased. Moreover, duration of the secondary phase showed a significant positive association with the number of pentastomes. These results suggest that the intensity of pentastome load exerts a weak effect on the metabolism of resting geckos, but a strong physiological effect on geckos that have recently been active; we speculate this occurs via mechanical constraints on breathing. Our results provide a potential mechanism by which pentastomes can reduce gecko fitness. PMID:26657838

  12. Physiological Status Drives Metabolic Rate in Mediterranean Geckos Infected with Pentastomes.

    PubMed

    Caballero, Isabel C; Sakla, Andrew J; Detwiler, Jillian T; Le Gall, Marion; Behmer, Spencer T; Criscione, Charles D

    2015-01-01

    Negative effects of parasites on their hosts are well documented, but the proximate mechanisms by which parasites reduce their host's fitness are poorly understood. For example, it has been suggested that parasites might be energetically demanding. However, a recent meta-analysis suggests that they have statistically insignificant effects on host resting metabolic rate (RMR). It is possible, though, that energetic costs associated with parasites are only manifested during and/or following periods of activity. Here, we measured CO2 production (a surrogate for metabolism) in Mediterranean geckos (Hemidactylus turcicus) infected with a lung parasite, the pentastome Raillietiella indica, under two physiological conditions: rested and recently active. In rested geckos, there was a negative, but non-significant association between the number of pentastomes (i.e., infection intensity) and CO2 production. In recently active geckos (chased for 3 minutes), we recorded CO2 production from its maximum value until it declined to a stationary phase. We analyzed this decline as a 3 phase function (initial decline, secondary decline, stationary). Geckos that were recently active showed, in the secondary phase, a significant decrease in CO2 production as pentastome intensity increased. Moreover, duration of the secondary phase showed a significant positive association with the number of pentastomes. These results suggest that the intensity of pentastome load exerts a weak effect on the metabolism of resting geckos, but a strong physiological effect on geckos that have recently been active; we speculate this occurs via mechanical constraints on breathing. Our results provide a potential mechanism by which pentastomes can reduce gecko fitness. PMID:26657838

  13. Extension of the CAPRAM mechanism with the improved mechanism generator GECKO-A

    NASA Astrophysics Data System (ADS)

    Bräuer, Peter; Mouchel-Vallon, Camille; Tilgner, Andreas; Wolke, Ralf; Aumont, Bernard; Herrmann, Hartmut

    2013-04-01

    Organic compounds are an ubiquitous constituent of the tropospheric multiphase system. With either biogenic or anthropogenic sources, they have a major influence on the atmospheric multiphase system and thus have become a main research topic within the last decades. Modelling can provide a useful tool to explore the tropospheric multiphase chemistry. While in the gas phase several comprehensive near-explicit mechanisms exist, in the aqueous phase those mechanisms are very limited. The current study aims to advance the currently most comprehensive aqueous phase mechanism CAPRAM 3.0 by means of automated mechanism construction. Therefore, the mechanism generator GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere; see Aumont et al., 2005) has been advanced to the aqueous phase. A protocol has been designed for automated mechanism construction based on reviewed experimental data and evaluated prediction methods. The generator is able to describe the oxidation of aliphatic organic compounds by OH and NO3. For the mechanism construction, mainly structure-activity relationships are used, which are completed by Evans-Polanyi-type correlations and further suitable estimates. GECKO-A has been used to create new CAPRAM versions, where branching ratios are introduced and new chemical subsystems with species with up to 4 carbon atoms are added. The currently most comprehensive version, CAPRAM 3.7, includes about 2000 aqueous phase species and more than 3300 reactions in the aqueous phase. Box model studies have been performed using a meteorological scenario with non-permanent clouds. Besides the investigation of the concentration-time profiles, detailed time-resolved flux analyses have been performed. Several aqueous phase subsystems have been investigated, such as the formation of oxidised mono- and diacids in the aqueous phase, as well as interactions to inorganic cycles and the influence on the gas phase chemistry and composition. Results

  14. Extension of the CAPRAM mechanism with the improved mechanism generator GECKO-A

    NASA Astrophysics Data System (ADS)

    Herrmann, H.; Bräuer, P.; Mouchel-Vallon, C.; Tilgner, A.; Wolke, R.; Aumont, B.

    2013-12-01

    The ubiquitous abundance of organic compounds in natural and anthropogenically influenced eco-systems has put these compounds into the focus of environmental research. To investigate the chemistry of organic compounds in the tropospheric multiphase system, modelling can provide a useful tool. While in the gas phase several comprehensive near-explicit mechanisms exist, in the aqueous phase those mechanisms are very limited. The present study aims to advance the currently most comprehensive aqueous phase mechanism CAPRAM 3.0n (Tilgner and Herrmann, 2010; Bräuer et al., 2013) by means of automated mechanism self-construction. Therefore, the mechanism generator GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere; see Aumont et al., 2005) has been advanced to the aqueous phase. A protocol has been designed for automated mechanism construction based on reviewed experimental data and evaluated prediction methods. The generator is able to describe the oxidation of aliphatic organic compounds by OH and NO3. For the mechanism construction, mainly structure-activity relationships are used. They are completed by Evans-Polanyi-type correlations, which have been further improved for the purpose of automated mechanism self-construction. GECKO-A has been used to create new CAPRAM versions, where branching ratios are introduced and new chemical subsystems with species with up to 4 carbon atoms are added. The currently most comprehensive version, CAPRAM 3.5alpha, includes about 2000 aqueous phase species and more than 3300 reactions in the aqueous phase. Process studies with the box model SPACCIM (SPectral Aerosol Cloud Chemistry Interaction Model; Wolke et al., 2005) have been performed using a meteorological scenario with non-permanent clouds. Besides the investigation of the concentration-time profiles, detailed time-resolved flux analyses have been performed. Several aqueous phase subsystems have been investigated, such as the formation of

  15. Dynamic stabilization of a bistable suspension system attached to a flexible host structure for operational safety enhancement

    NASA Astrophysics Data System (ADS)

    Yang, Kai; Harne, R. L.; Wang, K. W.; Huang, Hai

    2014-12-01

    In engineering applications, a suspension system may be attached to a flexible host structure, e.g. spacecraft truss, to provide vibration isolation for sensitive instrumentation, where the suspension and host structure dynamics are strongly coupled. For linear suspensions, a resonance normally occurs adjacent to the roll-off frequency band, which significantly and detrimentally amplifies vibration transmission. To avoid the adverse resonance for operational safety enhancement, this research proposes a nonlinear bistable suspension and evaluates its performance when attached to a flexible host structure. Dynamic models of the bistable and comparable linear suspensions attached to the host structure are formulated, and steady-state responses are predicted using analytical and numerical methods. Results show that the bistable suspension can eliminate the harmful resonance via a dynamic stabilization phenomenon, and simultaneously retains the favorable isolation performance in the roll-off bandwidth as compared to the linear suspension. Series of experimental investigations support the analytical and numerical findings and help define design guidelines for operational safety improvement.

  16. Evaluation of Underwater Adhesives and Friction Coatings for In Situ Attachment of Fiber Optic Sensor System for Subsea Applications

    NASA Technical Reports Server (NTRS)

    Tang, Henry H.; Le, Suy Q.; Orndoff, Evelyne S.; Smith, Frederick D.; Tapia, Alma S.; Brower, David V.

    2012-01-01

    Integrity and performance monitoring of subsea pipelines and structures provides critical information for managing offshore oil and gas production operation and preventing environmentally damaging and costly catastrophic failure. Currently pipeline monitoring devices require ground assembly and installation prior to the underwater deployment of the pipeline. A monitoring device that could be installed in situ on the operating underwater structures could enhance the productivity and improve the safety of current offshore operation. Through a Space Act Agreement (SAA) between the National Aeronautics and Space Administration (NASA) Johnson Space Center (JSC) and Astro Technology, Inc. (ATI), JSC provides technical expertise and testing facilities to support the development of fiber optic sensor technologies by ATI. This paper details the first collaboration effort between NASA JSC and ATI in evaluating underwater applicable adhesives and friction coatings for attaching fiber optic sensor system to subsea pipeline. A market survey was conducted to examine different commercial ]off ]the ]shelf (COTS) underwater adhesive systems and to select adhesive candidates for testing and evaluation. Four COTS epoxy based underwater adhesives were selected and evaluated. The adhesives were applied and cured in simulated seawater conditions and then evaluated for application characteristics and adhesive strength. The adhesive that demonstrated the best underwater application characteristics and highest adhesive strength were identified for further evaluation in developing an attachment system that could be deployed in the harsh subsea environment. Various friction coatings were also tested in this study to measure their shear strengths for a mechanical clamping design concept for attaching fiber optic sensor system. A COTS carbide alloy coating was found to increase the shear strength of metal to metal clamping interface by up to 46 percent. This study provides valuable data for

  17. Physical and metallurgical considerations of failures of soldered bars in bar attachment systems for implant overdentures: a review of the literature.

    PubMed

    Waddell, J Neil; Payne, Alan G T; Swain, Michael V

    2006-10-01

    The purpose of this literature review was to identify the etiological factors of failure of soldered bars in bar attachment systems for removable implant overdentures. A search of MEDLINE using the key words "bar attachment systems" was performed of English language peer-reviewed journals published between 1975 and 2005. Clinical studies of implant overdentures with prosthodontic maintenance complications of bar attachment systems were identified to establish the perceived etiology of failure. A further search of MEDLINE using the key words "solder joint" was also performed of the fixed prosthodontic literature to identify specific factors affecting the strength, fatigue resistance, and quality of gold solder joints used for bar attachment systems. The first search on bar attachment systems produced evidence of low failure rates of interabutment bars, but higher failure rates of bars where distal cantilever extensions were used. There were no explanations or descriptions of the nature of those failures in the clinical studies reviewed. The second search on fixed prosthodontic literature identified multiple factors that could potentially relate to the failed solder joints with bar attachments. Two potential sites of failure in bar attachments with distal cantilevers were identified, and a simple estimate of the tensile stresses at the solder joints was performed. The values found are comparable to the fatigue failure stresses reported in the searched literature. PMID:17052473

  18. A Jungian contribution to a dynamic systems understanding of disorganized attachment.

    PubMed

    Carter, Linda

    2011-06-01

    This panel emerged from shared clinical concerns when working with adult patients whose presentation style was reminiscent of a disorganized (Type D) infant attachment pattern. Psychotherapeutic work with such patients poses complicated transference and countertransference dilemmas which are addressed by all four panellists via theory and clinical vignettes. In common is an interest in contemporary attachment, neuroscience and trauma theories and their relationship to analytical psychology. Intergenerational trauma seems to be a salient factor in the evolution of fragmented and fragmenting interactions that lead to failures in self-coherence and healthy interpersonal relationships. Such early relational trauma is compounded by further episodes of abuse and neglect leading to failure in a core sense of self. These clinicians share how they have integrated theory and practice in order to help dissociated and disorganized patients to transform their dark and extraordinary suffering through implicit and explicit experiences with the analyst into new, life giving patterns of relationship with self and others. The alchemy of transformation, both positive and negative, is evident in the case material presented. PMID:21675978

  19. Folklore and traditional ecological knowledge of geckos in Southern Portugal: implications for conservation and science.

    PubMed

    Ceríaco, Luis M P; Marques, Mariana P; Madeira, Natália C; Vila-Viçosa, Carlos M; Mendes, Paula

    2011-01-01

    Traditional Ecological Knowledge (TEK) and folklore are repositories of large amounts of information about the natural world. Ideas, perceptions and empirical data held by human communities regarding local species are important sources which enable new scientific discoveries to be made, as well as offering the potential to solve a number of conservation problems. We documented the gecko-related folklore and TEK of the people of southern Portugal, with the particular aim of understanding the main ideas relating to gecko biology and ecology. Our results suggest that local knowledge of gecko ecology and biology is both accurate and relevant. As a result of information provided by local inhabitants, knowledge of the current geographic distribution of Hemidactylus turcicus was expanded, with its presence reported in nine new locations. It was also discovered that locals still have some misconceptions of geckos as poisonous and carriers of dermatological diseases. The presence of these ideas has led the population to a fear of and aversion to geckos, resulting in direct persecution being one of the major conservation problems facing these animals. It is essential, from both a scientific and conservationist perspective, to understand the knowledge and perceptions that people have towards the animals, since, only then, may hitherto unrecognized pertinent information and conservation problems be detected and resolved. PMID:21892925

  20. Shear adhesion strength of thermoplastic gecko-inspired synthetic adhesive exceeds material limits.

    PubMed

    Gillies, Andrew G; Fearing, Ronald S

    2011-09-20

    Natural gecko array wearless dynamic friction has recently been reported for 30,000 cycles on a smooth substrate. Following these findings, stiff polymer gecko-inspired synthetic adhesives have been proposed for high-cycle applications such as robot feet. Here we examine the behavior of high-density polyethylene (HDPE) and polypropylene (PP) microfiber arrays during repeated cycles of engagement on a glass surface, with a normal preload of less than 40 kPa. We find that fiber arrays maintained 54% of the original shear stress of 300 kPa after 10,000 cycles, despite showing a marked plastic deformation of fiber tips. This deformation could be due to shear-induced plastic creep of the fiber tips from high adhesion forces, adhesive wear, or thermal effects. We hypothesize that a fundamental material limit has been reached for these fiber arrays and that future gecko synthetic adhesive designs must take into account the high adhesive forces generated to avoid damage. Although the synthetic material and natural gecko arrays have a similar elastic modulus, the synthetic material does not show the same wear-free dynamic friction as the gecko. PMID:21848321

  1. Folklore and traditional ecological knowledge of geckos in Southern Portugal: implications for conservation and science

    PubMed Central

    2011-01-01

    Traditional Ecological Knowledge (TEK) and folklore are repositories of large amounts of information about the natural world. Ideas, perceptions and empirical data held by human communities regarding local species are important sources which enable new scientific discoveries to be made, as well as offering the potential to solve a number of conservation problems. We documented the gecko-related folklore and TEK of the people of southern Portugal, with the particular aim of understanding the main ideas relating to gecko biology and ecology. Our results suggest that local knowledge of gecko ecology and biology is both accurate and relevant. As a result of information provided by local inhabitants, knowledge of the current geographic distribution of Hemidactylus turcicus was expanded, with its presence reported in nine new locations. It was also discovered that locals still have some misconceptions of geckos as poisonous and carriers of dermatological diseases. The presence of these ideas has led the population to a fear of and aversion to geckos, resulting in direct persecution being one of the major conservation problems facing these animals. It is essential, from both a scientific and conservationist perspective, to understand the knowledge and perceptions that people have towards the animals, since, only then, may hitherto unrecognized pertinent information and conservation problems be detected and resolved. PMID:21892925

  2. Sticking to the story: outstanding challenges in gecko-inspired adhesives.

    PubMed

    Niewiarowski, Peter H; Stark, Alyssa Y; Dhinojwala, Ali

    2016-04-01

    The natural clinging ability of geckos has inspired hundreds of studies seeking design principles that could be applied to creating synthetic adhesives with the same performance capabilities as the gecko: adhesives that use no glue, are self-cleaning and reusable, and are insensitive to a wide range of surface chemistries and roughness. Important progress has been made, and the basic mechanics of how 'hairy' adhesives work have been faithfully reproduced, advancing theory in surface science and portending diverse practical applications. However, after 15 years, no synthetic mimic can yet perform as well as a gecko and simultaneously meet of all the criteria listed above. Moreover, processes for the production of inexpensive and scalable products are still not clearly in view. Here, we discuss our perspective on some of the gaps in understanding that still remain; these gaps in our knowledge should stimulate us to turn to deeper study of the way in which free-ranging geckos stick to the variety of surfaces found in their natural environments and to a more complete analysis of the materials composing the gecko toe pads. PMID:27030772

  3. Detection rates of geckos in visual surveys: Turning confounding variables into useful knowledge

    USGS Publications Warehouse

    Lardner, Bjorn; Rodda, Gordon H.; Yackel Adams, Amy A.; Savidge, Julie A.; Reed, Robert N.

    2016-01-01

    Transect surveys without some means of estimating detection probabilities generate population size indices prone to bias because survey conditions differ in time and space. Knowing what causes such bias can help guide the collection of relevant survey covariates, correct the survey data, anticipate situations where bias might be unacceptably large, and elucidate the ecology of target species. We used negative binomial regression to evaluate confounding variables for gecko (primarily Hemidactylus frenatus and Lepidodactylus lugubris) counts on 220-m-long transects surveyed at night, primarily for snakes, on 9,475 occasions. Searchers differed in gecko detection rates by up to a factor of six. The worst and best headlamps differed by a factor of at least two. Strong winds had a negative effect potentially as large as those of searchers or headlamps. More geckos were seen during wet weather conditions, but the effect size was small. Compared with a detection nadir during waxing gibbous (nearly full) moons above the horizon, we saw 28% more geckos during waning crescent moons below the horizon. A sine function suggested that we saw 24% more geckos at the end of the wet season than at the end of the dry season. Fluctuations on a longer timescale also were verified. Disturbingly, corrected data exhibited strong short-term fluctuations that covariates apparently failed to capture. Although some biases can be addressed with measured covariates, others will be difficult to eliminate as a significant source of error in longterm monitoring programs.

  4. Testing the island effect on phenotypic diversification: insights from the Hemidactylus geckos of the Socotra Archipelago

    PubMed Central

    Garcia-Porta, Joan; Šmíd, Jiří; Sol, Daniel; Fasola, Mauro; Carranza, Salvador

    2016-01-01

    Island colonization is often assumed to trigger extreme levels of phenotypic diversification. Yet, empirical evidence suggests that it does not always so. In this study we test this hypothesis using a completely sampled mainland-island system, the arid clade of Hemidactylus, a group of geckos mainly distributed across Africa, Arabia and the Socotra Archipelago. To such purpose, we generated a new molecular phylogeny of the group on which we mapped body size and head proportions. We then explored whether island and continental taxa shared the same morphospace and differed in their disparities and tempos of evolution. Insular species produced the most extreme sizes of the radiation, involving accelerated rates of evolution and higher disparities compared with most (but not all) of the continental groups. In contrast, head proportions exhibited constant evolutionary rates across the radiation and similar disparities in islands compared with the continent. These results, although generally consistent with the notion that islands promote high morphological disparity, reveal at the same time a complex scenario in which different traits may experience different evolutionary patterns in the same mainland-island system and continental groups do not always present low levels of morphological diversification compared to insular groups. PMID:27071837

  5. Testing the island effect on phenotypic diversification: insights from the Hemidactylus geckos of the Socotra Archipelago.

    PubMed

    Garcia-Porta, Joan; Šmíd, Jiří; Sol, Daniel; Fasola, Mauro; Carranza, Salvador

    2016-01-01

    Island colonization is often assumed to trigger extreme levels of phenotypic diversification. Yet, empirical evidence suggests that it does not always so. In this study we test this hypothesis using a completely sampled mainland-island system, the arid clade of Hemidactylus, a group of geckos mainly distributed across Africa, Arabia and the Socotra Archipelago. To such purpose, we generated a new molecular phylogeny of the group on which we mapped body size and head proportions. We then explored whether island and continental taxa shared the same morphospace and differed in their disparities and tempos of evolution. Insular species produced the most extreme sizes of the radiation, involving accelerated rates of evolution and higher disparities compared with most (but not all) of the continental groups. In contrast, head proportions exhibited constant evolutionary rates across the radiation and similar disparities in islands compared with the continent. These results, although generally consistent with the notion that islands promote high morphological disparity, reveal at the same time a complex scenario in which different traits may experience different evolutionary patterns in the same mainland-island system and continental groups do not always present low levels of morphological diversification compared to insular groups. PMID:27071837

  6. Intermediate filament immunohistochemistry of astroglial cells in the leopard gecko, Eublepharis macularius.

    PubMed

    Lazzari, Maurizio; Franceschini, Valeria

    2005-11-01

    The distribution of intermediate filament molecular markers, glial fibrillary acidic protein (GFAP) and vimentin, has been studied in the central nervous system (CNS) of the adult leopard gecko, Eublepharis macularius. This immunohistochemical study points out the presence of different astroglial cell types. The main pattern is constituted by ependymal radial glia, which have their cell bodies located in the ependymal layer throughout the brain ventricular system. Radial glia proper or radial astrocytes show their cell bodies displaced from the ependymal layer into a periependymal zone and are observed only in the spinal cord. Star-shaped astrocytes are scarce. They are detected in the ventral and lateral regions of the diencephalon and mesencephalon, in the superficial layer of the optic tectum, in the ventral medulla oblongata, and in the ventral and lateral spinal cord. In the different regions of the CNS, the staining intensity appears not to be identical even in the same cellular type. The results reported in the present study show an heterogeneous feature of the astroglial pattern in E. macularius. PMID:16222544

  7. Testing the island effect on phenotypic diversification: insights from the Hemidactylus geckos of the Socotra Archipelago

    NASA Astrophysics Data System (ADS)

    Garcia-Porta, Joan; Šmíd, Jiří; Sol, Daniel; Fasola, Mauro; Carranza, Salvador

    2016-04-01

    Island colonization is often assumed to trigger extreme levels of phenotypic diversification. Yet, empirical evidence suggests that it does not always so. In this study we test this hypothesis using a completely sampled mainland-island system, the arid clade of Hemidactylus, a group of geckos mainly distributed across Africa, Arabia and the Socotra Archipelago. To such purpose, we generated a new molecular phylogeny of the group on which we mapped body size and head proportions. We then explored whether island and continental taxa shared the same morphospace and differed in their disparities and tempos of evolution. Insular species produced the most extreme sizes of the radiation, involving accelerated rates of evolution and higher disparities compared with most (but not all) of the continental groups. In contrast, head proportions exhibited constant evolutionary rates across the radiation and similar disparities in islands compared with the continent. These results, although generally consistent with the notion that islands promote high morphological disparity, reveal at the same time a complex scenario in which different traits may experience different evolutionary patterns in the same mainland-island system and continental groups do not always present low levels of morphological diversification compared to insular groups.

  8. The oxytocin system promotes resilience to the effects of neonatal isolation on adult social attachment in female prairie voles.

    PubMed

    Barrett, C E; Arambula, S E; Young, L J

    2015-01-01

    Genes and social experiences interact to create variation in social behavior and vulnerability to develop disorders of the social domain. Socially monogamous prairie voles display remarkable diversity in neuropeptide receptor systems and social behavior. Here, we examine the interaction of early-life adversity and brain oxytocin receptor (OTR) density on adult social attachment in female prairie voles. First, pups were isolated for 3 h per day, or unmanipulated, from postnatal day 1-14. Adult subjects were tested on the partner preference (PP) test to assess social attachment and OTR density in the brain was quantified. Neonatal social isolation impaired female PP formation, without affecting OTR density. Accumbal OTR density was, however, positively correlated with the percent of time spent huddling with the partner in neonatally isolated females. Females with high accumbal OTR binding were resilient to neonatal isolation. These results are consistent with the hypothesis that parental nurturing shapes neural systems underlying social relationships by enhancing striatal OTR signaling. Thus, we next determined whether early touch, mimicking parental licking and grooming, stimulates hypothalamic OT neuron activity. Tactile stimulation induced immediate-early gene activity in OT neurons in neonates. Finally, we investigated whether pharmacologically potentiating OT release using a melanocortin 3/4 agonist, melanotan-II (10 mg kg(-1) subcutaneously), would mitigate the social isolation-induced impairments in attachment behavior. Neonatal melanotan-II administration buffered against the effects of early isolation on partner preference formation. Thus, variation in accumbal OTR density and early OT release induced by parental nurturing may moderate susceptibility to early adverse experiences, including neglect. PMID:26196439

  9. Role of seta angle and flexibility in the gecko adhesion mechanism

    NASA Astrophysics Data System (ADS)

    Hu, Congcong; Alex Greaney, P.

    2014-08-01

    A model is developed to describe the reversible nature of gecko dry adhesion. The central aspect of this model is that the seta can be easily peeled away from the contacting surface by a small moment at the contact tip. It is shown that this contact condition is very sensitive, but can result in robust adhesion if individual setae are canted and highly flexible. In analogy to the "cone of friction," we consider the "adhesion region"—the domain of normal and tangential forces that maintain adhesion. Results demonstrate that this adhesion region is highly asymmetric enabling the gecko to adhere under a variety of loading conditions associated with scuttling horizontally, vertically, and inverted. Moreover, under each of these conditions, there is a low energy path to de-adhesion. In this model, obliquely canted seta (as possessed by geckos) rather than vertically aligned fibers (common in synthetic dry adhesive) provides the most robust adhesion.

  10. Highly durable and unidirectionally stooped polymeric nanohairs for gecko-like dry adhesive

    NASA Astrophysics Data System (ADS)

    Im, Hyeon Seong; Kwon, Ki Yoon; Kim, Jong Uk; Kim, Kwang Su; Yi, Hoon; Yoo, Pil J.; Pang, Changhyun; Jeong, Hoon Eui; Kim, Tae-il

    2015-10-01

    Gecko-like dry adhesive using high aspect ratio polymeric nanohairs has insuperable limitations, although it has huge potential in many applications. Repeated harsh contacts on a target substrate lead to physical collapse of nanohairs and significant degradation of the adhesion property, because the polymeric nanohairs are quite fragile due to poor mechanical robustness. Herein, we demonstrate a highly robust gecko-like dry adhesive with unidirectionally stooped polymeric nanohairs (diameter 100 nm) with a high aspect ratio (∼9) using an ultrathin metal coating. 100 cycles of repeated adhesion tests with 1 N preloading force did not significantly degrade adhesion or cause collapse of nanohairs. We believe that this approach allows gecko-like dry adhesive to be utilized in many related applications and diverse industry interests.

  11. Highly durable and unidirectionally stooped polymeric nanohairs for gecko-like dry adhesive.

    PubMed

    Im, Hyeon Seong; Kwon, Ki Yoon; Kim, Jong Uk; Kim, Kwang Su; Yi, Hoon; Yoo, Pil J; Pang, Changhyun; Jeong, Hoon Eui; Kim, Tae-il

    2015-10-16

    Gecko-like dry adhesive using high aspect ratio polymeric nanohairs has insuperable limitations, although it has huge potential in many applications. Repeated harsh contacts on a target substrate lead to physical collapse of nanohairs and significant degradation of the adhesion property, because the polymeric nanohairs are quite fragile due to poor mechanical robustness. Herein, we demonstrate a highly robust gecko-like dry adhesive with unidirectionally stooped polymeric nanohairs (diameter 100 nm) with a high aspect ratio (∼9) using an ultrathin metal coating. 100 cycles of repeated adhesion tests with 1 N preloading force did not significantly degrade adhesion or cause collapse of nanohairs. We believe that this approach allows gecko-like dry adhesive to be utilized in many related applications and diverse industry interests. PMID:26391964

  12. The effect of contaminants on the adhesion of the spatulae of a gecko.

    PubMed

    Jeng, Yeau-Ren; Mao, Chien-Ping

    2010-12-01

    Many researchers have reported that the robust adhesion that enables geckos to move quickly and securely across a range of vertical and horizontal surfaces is provided by the hierarchical structure of their feet (i.e. lamellae, setae, spatulae, etc.). Maintaining this robust adhesion requires an intimate contact between the terminal tips of the spatulae and the surface. The aim of this study was to investigate the effect on the adhesive properties of the spatulae when a particle becomes trapped at the contact surface. Using the Johnson, Kendall and Roberts (JKR) theory, a model was constructed to assist in the analysis of the interactions between the spatula tip, the particle and the surface. The results showed that the keratin (the natural material of the spatula) provides a robust system for adhesion even when there is a particle in the contact area, and the effective contact area of spatulae will be 80%. When the particle is significantly harder than the surface, the adhesion properties of the contact surface influenced by the particle will be more obvious. The results also reveal that the generated adhesion is considerably higher when the spatula is in contact with a softer surface, such as wood or concrete, rather than a hard surface, such as glass or SiO2. PMID:21289442

  13. Effect of incubation temperature and androgens on dopaminergic activity in the leopard gecko, Eublepharis macularius.

    PubMed

    Dias, Brian George; Ataya, Ramona Sousan; Rushworth, David; Zhao, Jun; Crews, David

    2007-04-01

    Male leopard geckos that hatch from eggs incubated at a female-biased temperature (Tf) behave differently when compared with males hatching at a temperature which produces a male-biased sex ratio (Tm). We investigated the effect of incubation temperature and androgen implantation on aspects of the dopaminergic system of Tf and Tm males. Our data suggest that more dopamine (DA) is stored in the nucleus accumbens of naive Tf males compared with naïve Tm males when they encounter a receptive female conspecific across a barrier. No difference was measured in the preoptic area and the ventral tegmental area (VTA). This difference in intracellular DA levels in a motivation-related brain nucleus might be correlated with differences in sociosexual behavior observed between the two morphs. There were no differences in tyrosine hydroxylase (TH) expressing cell numbers in the VTA of cholesterol (CH)-implanted naive castrated Tf and Tm males. Only Tf males implanted with testosterone had significantly higher TH immunopositive cell numbers in the VTA compared with CH- and dihydrotestosterone-implanted Tf males. These data indicate that both the embryonic environment as well as the circulating hormonal milieu can modulate neurochemistry, which might in turn be a basis for individual variation in behavior. PMID:17443813

  14. Rate-dependent frictional adhesion in natural and synthetic gecko setae

    PubMed Central

    Gravish, Nick; Wilkinson, Matt; Sponberg, Simon; Parness, Aaron; Esparza, Noe; Soto, Daniel; Yamaguchi, Tetsuo; Broide, Michael; Cutkosky, Mark; Creton, Costantino; Autumn, Kellar

    2010-01-01

    Geckos owe their remarkable stickiness to millions of dry, hard setae on their toes. In this study, we discovered that gecko setae stick more strongly the faster they slide, and do not wear out after 30 000 cycles. This is surprising because friction between dry, hard, macroscopic materials typically decreases at the onset of sliding, and as velocity increases, friction continues to decrease because of a reduction in the number of interfacial contacts, due in part to wear. Gecko setae did not exhibit the decrease in adhesion or friction characteristic of a transition from static to kinetic contact mechanics. Instead, friction and adhesion forces increased at the onset of sliding and continued to increase with shear speed from 500 nm s−1 to 158 mm s−1. To explain how apparently fluid-like, wear-free dynamic friction and adhesion occur macroscopically in a dry, hard solid, we proposed a model based on a population of nanoscopic stick–slip events. In the model, contact elements are either in static contact or in the process of slipping to a new static contact. If stick–slip events are uncorrelated, the model further predicted that contact forces should increase to a critical velocity (V*) and then decrease at velocities greater than V*. We hypothesized that, like natural gecko setae, but unlike any conventional adhesive, gecko-like synthetic adhesives (GSAs) could adhere while sliding. To test the generality of our results and the validity of our model, we fabricated a GSA using a hard silicone polymer. While sliding, the GSA exhibited steady-state adhesion and velocity dependence similar to that of gecko setae. Observations at the interface indicated that macroscopically smooth sliding of the GSA emerged from randomly occurring stick–slip events in the population of flexible fibrils, confirming our model predictions. PMID:19493896

  15. Vertical anisotropic microfibers for a gecko-inspired adhesive.

    PubMed

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2012-06-12

    Geckos are able to adhere strongly and release easily from surfaces because the structurally anisotropic fibers on their toes naturally exhibit force anisotropy based on the direction of articulation. Here, semicircular fibers, with varying amounts of contact area on the two faces, are investigated to ascertain whether fiber shape can be used to gain anisotropy in shear and shear adhesion forces. Testing of 10-μm-diameter polydimethylsiloxane (PDMS) fibers against a 4-mm-diameter flat glass puck show that shear and shear adhesion forces were two to five times greater when in-plane movement caused the flat face, rather than the curved face, of the fiber to come in contact with the glass puck. The directional adhesion and shear force anisotropy results are close to theoretical approximations using the Kendall peel model and clearly demonstrate how fiber shape may be used to influence the properties of the adhesive. This result has broad applicability, and by combining the results shown here with other current vertical and angled designs, synthetic adhesives can be further improved to behave more like their natural counterparts. PMID:22568809

  16. Bayesian species delimitation in West African forest geckos (Hemidactylus fasciatus)

    PubMed Central

    Leaché, Adam D.; Fujita, Matthew K.

    2010-01-01

    Genealogical data are an important source of evidence for delimiting species, yet few statistical methods are available for calculating the probabilities associated with different species delimitations. Bayesian species delimitation uses reversible-jump Markov chain Monte Carlo (rjMCMC) in conjunction with a user-specified guide tree to estimate the posterior distribution for species delimitation models containing different numbers of species. We apply Bayesian species delimitation to investigate the speciation history of forest geckos (Hemidactylus fasciatus) from tropical West Africa using five nuclear loci (and mtDNA) for 51 specimens representing 10 populations. We find that species diversity in H. fasciatus is currently underestimated, and describe three new species to reflect the most conservative estimate for the number of species in this complex. We examine the impact of the guide tree, and the prior distributions on ancestral population sizes (θ) and root age (τ0), on the posterior probabilities for species delimitation. Mis-specification of the guide tree or the prior distribution for θ can result in strong support for models containing more species. We describe a new statistic for summarizing the posterior distribution of species delimitation models, called speciation probabilities, which summarize the posterior support for each speciation event on the starting guide tree. PMID:20519219

  17. Effects on milk yield of milking interval regularity and teat cup attachment failures with robotic milking systems.

    PubMed

    Bach, Alex; Busto, Isabel

    2005-02-01

    A database consisting of 35291 milking records from 83 cows was built over a period of 10 months with the objectives of studying the effect of teat cup attachment failures and milking interval regularity on milk production with an automated milking system (AMS). The database collected records of lactation number, days in milk (DIM), milk production, interval between milkings (for both the entire udder and individual quarters in case of a teat cup attachment failure) and average and peak milk flows for each milking. The weekly coefficient of variation (CV) of milking intervals was used as a measure of milking regularity. DIM, milking intervals, and CV of milking intervals were divided into four categories coinciding with the four quartiles of their respective distributions. The data were analysed by analysis of variance with cow as a random effect and lactation number, DIM, the occurrence of a milking failure, and the intervals between milkings or the weekly CV of milking intervals as fixed effects. The incidence of attachment failures was 7.6% of total milkings. Milk production by quarters affected by a milking failure following the failure was numerically greater owing to the longer interval between milkings. When accounting for the effect of milking intervals, milk production by affected quarters following a milking failure was 26% lower than with regular milkings. However, the decrease in milk production by quarters affected by milking failures was more severe as DIM increased. Average and peak milk flows by quarters affected by a milking failure were lower than when milkings occurred normally. However, milk production recovered its former level within seven milkings following a milking failure. Uneven frequency (weekly CV of milking intervals >27%) decreased daily milk yield, and affected multiparous more negatively than primiparous cows. PMID:15747737

  18. Why have not the hairs on the feet of gecko been smaller?

    NASA Astrophysics Data System (ADS)

    Su, Yewang; He, Shijie; Hwang, Keh-Chih; Ji, Baohua

    2012-10-01

    The nanometer size of the tiny hair is the key to the secret of strong stickiness of gecko's feet, by which the hair can achieve the maximum adhesion strength that is insensitive to the interfacial flaws with substrate surface. But the question why the hairs have not been smaller is not answered yet. In this study, we derived a geometric parameter of the surface structures considering lateral interaction among hairs, which gives a critical size below which these hairs will bunch together and cause failure of the adhesion, suggesting a lower limit of the dimension of hairs on gecko's feet.

  19. A flat and cost effective actuator based on superabsorbent polymer driving a skin attachable drug delivery system

    NASA Astrophysics Data System (ADS)

    Vosseler, Michael; Clemenz, Markus; Zengerle, Roland

    2012-10-01

    We present a flat and cost effective volume displacement actuator based on superabsorbent polymer. It offers slow kinetics and is able to work against reasonable back-pressures, e.g. 0.50 ml in 235 min at 140 kPa. It is predestined for low-cost skin attachable drug delivery devices. The actuator consists of a plastic ring filled with superabsorbent polymer granulate. It is sealed with a thermoplastic elastomeric membrane on one side and a stiff filter membrane on the other side. After adding a defined amount (e.g. 2 or 10 ml) of swelling agent the actuator shows a fast initial volume displacement within a few minutes followed by a slow continuous increase of this volume within hours. Minimized initial volume displacement and maximized displaced volume after 4 h cannot be combined in one actuator. A minimized initial displacement can be as low as 0.10 ml± 0.03 ml. A maximized displaced volume after 4 h can be 1.71 ml± 0.18 ml, not considering the initial effect. The back-pressure dependency of one selected actuator design was studied. At a back-pressure of 100 kPa the displaced volume is reduced by 33%. We investigated various actuator designs with varying surface area, hardness of the elastomeric membrane and superabsorbent polymer. Finally, we demonstrate a skin attachable drug delivery system based on the employment of the superabsorbent polymer actuator.

  20. An Attachable Electromagnetic Energy Harvester Driven Wireless Sensing System Demonstrating Milling-Processes and Cutter-Wear/Breakage-Condition Monitoring

    PubMed Central

    Chung, Tien-Kan; Yeh, Po-Chen; Lee, Hao; Lin, Cheng-Mao; Tseng, Chia-Yung; Lo, Wen-Tuan; Wang, Chieh-Min; Wang, Wen-Chin; Tu, Chi-Jen; Tasi, Pei-Yuan; Chang, Jui-Wen

    2016-01-01

    An attachable electromagnetic-energy-harvester driven wireless vibration-sensing system for monitoring milling-processes and cutter-wear/breakage-conditions is demonstrated. The system includes an electromagnetic energy harvester, three single-axis Micro Electro-Mechanical Systems (MEMS) accelerometers, a wireless chip module, and corresponding circuits. The harvester consisting of magnets with a coil uses electromagnetic induction to harness mechanical energy produced by the rotating spindle in milling processes and consequently convert the harnessed energy to electrical output. The electrical output is rectified by the rectification circuit to power the accelerometers and wireless chip module. The harvester, circuits, accelerometer, and wireless chip are integrated as an energy-harvester driven wireless vibration-sensing system. Therefore, this completes a self-powered wireless vibration sensing system. For system testing, a numerical-controlled machining tool with various milling processes is used. According to the test results, the system is fully self-powered and able to successfully sense vibration in the milling processes. Furthermore, by analyzing the vibration signals (i.e., through analyzing the electrical outputs of the accelerometers), criteria are successfully established for the system for real-time accurate simulations of the milling-processes and cutter-conditions (such as cutter-wear conditions and cutter-breaking occurrence). Due to these results, our approach can be applied to most milling and other machining machines in factories to realize more smart machining technologies. PMID:26907297

  1. An Attachable Electromagnetic Energy Harvester Driven Wireless Sensing System Demonstrating Milling-Processes and Cutter-Wear/Breakage-Condition Monitoring.

    PubMed

    Chung, Tien-Kan; Yeh, Po-Chen; Lee, Hao; Lin, Cheng-Mao; Tseng, Chia-Yung; Lo, Wen-Tuan; Wang, Chieh-Min; Wang, Wen-Chin; Tu, Chi-Jen; Tasi, Pei-Yuan; Chang, Jui-Wen

    2016-01-01

    An attachable electromagnetic-energy-harvester driven wireless vibration-sensing system for monitoring milling-processes and cutter-wear/breakage-conditions is demonstrated. The system includes an electromagnetic energy harvester, three single-axis Micro Electro-Mechanical Systems (MEMS) accelerometers, a wireless chip module, and corresponding circuits. The harvester consisting of magnets with a coil uses electromagnetic induction to harness mechanical energy produced by the rotating spindle in milling processes and consequently convert the harnessed energy to electrical output. The electrical output is rectified by the rectification circuit to power the accelerometers and wireless chip module. The harvester, circuits, accelerometer, and wireless chip are integrated as an energy-harvester driven wireless vibration-sensing system. Therefore, this completes a self-powered wireless vibration sensing system. For system testing, a numerical-controlled machining tool with various milling processes is used. According to the test results, the system is fully self-powered and able to successfully sense vibration in the milling processes. Furthermore, by analyzing the vibration signals (i.e., through analyzing the electrical outputs of the accelerometers), criteria are successfully established for the system for real-time accurate simulations of the milling-processes and cutter-conditions (such as cutter-wear conditions and cutter-breaking occurrence). Due to these results, our approach can be applied to most milling and other machining machines in factories to realize more smart machining technologies. PMID:26907297

  2. Comparative evaluation of three attached growth systems and a constructed wetland for in situ treatment of raw municipal wastewater.

    PubMed

    Loupasaki, E; Diamadopoulos, E

    2013-01-01

    The necessity to treat municipal wastewaters in situ, with a low cost, yet effective system, led to the research of alternative methods for wastewater treatment. Attached growth systems can be an alternative option. Three attached growth systems with different media substrate, a rockwool cubes unit, a Kaldnes rings unit and a plastic bottle caps unit were studied in comparison with a constructed wetland in order to evaluate their ability to treat raw municipal wastewater. The selection of the three different media was based on their high porosity and surface area, as well as their availability and price. Three different operating periods were carried out with variations in the organic loading rate and the feeding frequency. The units were fed intermittently with short resting periods, less than 32 h, and relative high mean organic loading rates of 70, 50 and 30 g chemical oxygen demand (COD)/(m2d), respectively for each operating period. The constructed wetland and the rockwool cubes unit were the most effective, with mean COD reduction as mass rate (mg/d) 88% and 88%, biological oxygen demand 78% and 76%, dissolved organic carbon 73% and 67%, and total suspended solids 91% and 92%, respectively. Total nitrogen reduction was significantly higher at the constructed wetland with mean reduction as mass rate 51%, 60% and 83% for each period, compared to 41%, 43% and 60%, respectively, of the rockwool cubes unit. This study showed that it is possible to design, build and operate in situ small and decentralized treatment systems by using readily available packing materials and with minimum wastewater pretreatment. PMID:24191485

  3. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, D.M.; McKernan, M.A.

    1994-02-15

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

  4. Magnetically attached sputter targets

    DOEpatents

    Makowiecki, Daniel M.; McKernan, Mark A.

    1994-01-01

    An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly.

  5. Quantification of three steroid hormone receptors of the leopard gecko (Eublepharis macularius), a lizard with temperature-dependent sex determination: their tissue distributions and the effect of environmental change on their expressions.

    PubMed

    Endo, Daisuke; Park, Min Kyun

    2003-12-01

    Sex steroid hormones play a central role in the reproduction of all vertebrates. These hormones function through their specific receptors, so the expression levels of the receptors may reflect the responsibility of target organs. However, there was no effective method to quantify the expression levels of these receptors in reptilian species. In this study, we established the competitive-PCR assay systems for the quantification of the mRNA expression levels of three sex steroid hormone receptors in the leopard gecko. These assay systems were successfully able to detect the mRNA expression level of each receptor in various organs of male adult leopard geckoes. The expression levels of mRNA of these receptors were highly various depending on the organs assayed. This is the first report regarding the tissue distributions of sex steroid hormone receptor expressions in reptile. The effects of environmental conditions on these hormone receptor expressions were also examined. After the low temperature and short photoperiod treatment for 6 weeks, only the androgen receptor expression was significantly increased in the testes. The competitive-PCR assay systems established in this report should be applicable for various studies of the molecular mechanism underlying the reproductive activity of the leopard gecko. PMID:14662317

  6. Integrating Recovery and the Narrative Attachment Systems Perspective to Working through Borderline Personality Disorder

    ERIC Educational Resources Information Center

    Bernardon, Stephanie; Pernice-Duca, Francesca

    2012-01-01

    Borderline personality disorder (BPD) presents a number of symptoms and adjustment issues for individuals, but it is also associated with a myriad of risks for the larger family system. A systemic perspective is crucial to comprehending the development of BPD. Promoting healthy relationships with one or more supportive adult enables the child to…

  7. Patterns of diversification in islands: A comparative study across three gecko genera in the Socotra Archipelago.

    PubMed

    Garcia-Porta, Joan; Morales, Hernán E; Gómez-Díaz, Elena; Sindaco, Roberto; Carranza, Salvador

    2016-05-01

    In this study we used the complete fauna of geckos of the Socotra Archipelago to test whether the three gecko genera co-occurring in the islands (Pristurus, Hemidactylus and Haemodracon) produced similar outcomes of morphological and climatic diversification. To test this, we produced a time-calibrated tree of 346 geckos including all 16 endemic species of the archipelago and 26 potential close-relatives in the continent. Our dating estimates revealed that most of the diversity of geckos in the archipelago was the consequence of in situ diversification. However not all genera shared similar patterns of diversification. While in Hemidactylus and Haemodracon this involved great differences in body size and low levels of climatic diversification (mostly involving sympatric distributions), an opposite pattern appeared in Pristurus in which most of the diversification involved shifts in climatic envelopes (mostly involving allopatric and parapatric distributions) but almost no size differentiation. Consistently with this, Pristurus was the only genus in which rates of size diversification in islands were substantially lower than in the continent. This illustrates how different groups can greatly differ in their patterns of intra-island diversification and highlights the importance of taxon-dependent factors at determining different patterns of diversification in the same insular context. PMID:26911521

  8. 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.

  9. Friction and adhesion of gecko-inspired PDMS flaps on rough surfaces.

    PubMed

    Yu, Jing; Chary, Sathya; Das, Saurabh; Tamelier, John; Turner, Kimberly L; Israelachvili, Jacob N

    2012-08-01

    Geckos have developed a unique hierarchical structure to maintain climbing ability on surfaces with different roughness, one of the extremely important parameters that affect the friction and adhesion forces between two surfaces. Although much attention has been paid on fabricating various structures that mimic the hierarchical structure of a gecko foot, yet no systematic effort, in experiment or theory, has been made to quantify the effect of surface roughness on the performance of the fabricated structures that mimic the hierarchical structure of geckos. Using a modified surface forces apparatus (SFA), we measured the adhesion and friction forces between microfabricated tilted PDMS flaps and optically smooth SiO(2) and rough SiO(2) surfaces created by plasma etching. Anisotropic adhesion and friction forces were measured when sliding the top glass surface along (+y) and against (-y) the tilted direction of the flaps. Increasing the surface roughness first increased the adhesion and friction forces measured between the flaps and the rough surface due to topological matching of the two surfaces but then led to a rapid decrease in both of these forces. Our results demonstrate that the surface roughness significantly affects the performance of gecko mimetic adhesives and that different surface textures can either increase or decrease the adhesion and friction forces of the fabricated adhesives. PMID:22779923

  10. Effects of reproductive condition, season, and site on selected temperatures of a viviparous gecko.

    PubMed

    Rock, J; Andrews, R M; Cree, A

    2000-01-01

    The relationship between thermal and reproductive biology is complex and poorly understood. We measured selected body temperatures (T(sel)) for the viviparous gecko Hoplodactylus maculatus. T(sel) was compared among pregnant females, nonpregnant females, and males from two sites: a cool site with biennially reproducing geckos and a warm site with annually reproducing geckos. T(sel) was measured at five times of day during three seasons and compared with microhabitat temperature (T(top)) and field body temperature (T(b)). T(sel) varied with time of day in all comparisons, and the effect of reproductive condition on T(sel) differed between sites and seasons. At both sites, when T(sel) differed between reproductive conditions, pregnant females had higher T(sel) than nonpregnant females and males. Stage of pregnancy affected the degree of elevation of T(sel). Measurements of microhabitat temperature and field T(b) showed that, even in the warmest season, geckos rarely had the opportunity to achieve T(sel) at the cool site but were able to do so at the warm site. The elevation of T(sel) with pregnancy is extreme in this species (up to 8 degrees C), which suggests that an increase in T(b) is critical to successful reproduction. Interactions between the effects of time of day, season, and reproductive condition on T(sel) must be considered in the assessment of thermoregulation in reptiles. PMID:10893174

  11. Footprints in the sand: independent reduction of subdigital lamellae in the Namib–Kalahari burrowing geckos

    PubMed Central

    Lamb, Trip; Bauer, Aaron M

    2005-01-01

    Many desert organisms exhibit convergence, and certain physical factors such as windblown sands have generated remarkably similar ecomorphs across divergent lineages. The burrowing geckos Colopus, Chondrodactylus and Palmatogecko occupy dune ecosystems in the Namib and Kalahari deserts of southwest Africa. Considered closely related, they share several putative synapomorphies, including reduced subdigital pads (toe pads) and spinose digital scales. Though recognized as part of Africa's ecologically diverse Pachydactylus Group, the burrowing geckos' precise phylogenetic affinities remain elusive. Convergent pedal modification provides a tenable alternative explaining the geckos' derived terrestriality and adaptation to Namib and Kalahari sands. We generated a molecular phylogeny for the Pachydactylus Group to examine evolutionary relationships among the burrowing geckos and infer historical patterns of pedal character change. Bayesian and parsimony analyses revealed all three burrowing genera to be deeply nested within Pachydactylus, each genus belonging to a separate clade. Strong support for these distinct clades indicates ecomorphological adaptations for burrowing have evolved independently three times in the southern Pachydactylus Group. We argue that the physical properties of Namib and Kalahari sands played a principal role in selecting for pedal similarity. PMID:16618680

  12. How do the substrate reaction forces acting on a gecko's limbs respond to inclines?

    NASA Astrophysics Data System (ADS)

    Wang, Zhouyi; Dai, Zhendong; Li, Wei; Ji, Aihong; Wang, Wenbao

    2015-02-01

    Locomotion is an essential character of animals, and excellent moving ability results from the delicate sensing of the substrate reaction forces (SRF) acting on body and modulating the behavior to adapt the motion requirement. The inclined substrates present in habitats pose a number of functional challenges to locomotion. In order to effectively overcome these challenges, climbing geckos execute complex and accurate movements that involve both the front and hind limbs. Few studies have examined gecko's SRF on steeper inclines of greater than 90°. To reveal how the SRFs acting on the front and hind limbs respond to angle incline changes, we obtained detailed measurements of the three-dimensional SRFs acting on the individual limbs of the tokay gecko while it climbed on an inclined angle of 0-180°. The fore-aft forces acting on the front and hind limbs show opposite trends on inverted inclines of greater than 120°, indicating propulsion mechanism changes in response to inclines. When the incline angles change, the forces exerted in the normal and fore-aft directions by gecko's front and hind limbs are reassigned to take full advantage of limbs' different roles in overcoming resistance and in propelling locomotion. This also ensures that weight acts in the angle range between the forces generated by the front and hind limbs. The change in the distribution of SRF with a change in the incline angle is directly linked to the favorable trade-off between locomotive maneuverability and stability.

  13. How do the substrate reaction forces acting on a gecko's limbs respond to inclines?

    PubMed

    Wang, Zhouyi; Dai, Zhendong; Li, Wei; Ji, Aihong; Wang, Wenbao

    2015-02-01

    Locomotion is an essential character of animals, and excellent moving ability results from the delicate sensing of the substrate reaction forces (SRF) acting on body and modulating the behavior to adapt the motion requirement. The inclined substrates present in habitats pose a number of functional challenges to locomotion. In order to effectively overcome these challenges, climbing geckos execute complex and accurate movements that involve both the front and hind limbs. Few studies have examined gecko's SRF on steeper inclines of greater than 90°. To reveal how the SRFs acting on the front and hind limbs respond to angle incline changes, we obtained detailed measurements of the three-dimensional SRFs acting on the individual limbs of the tokay gecko while it climbed on an inclined angle of 0-180°. The fore-aft forces acting on the front and hind limbs show opposite trends on inverted inclines of greater than 120°, indicating propulsion mechanism changes in response to inclines. When the incline angles change, the forces exerted in the normal and fore-aft directions by gecko's front and hind limbs are reassigned to take full advantage of limbs' different roles in overcoming resistance and in propelling locomotion. This also ensures that weight acts in the angle range between the forces generated by the front and hind limbs. The change in the distribution of SRF with a change in the incline angle is directly linked to the favorable trade-off between locomotive maneuverability and stability. PMID:25645733

  14. Comparison of the efficiencies of attached- versus suspended-growth SBR systems in the treatment of recycled paper mill wastewater.

    PubMed

    Muhamad, Mohd Hafizuddin; Sheikh Abdullah, Siti Rozaimah; Abu Hasan, Hassimi; Abd Rahim, Reehan Adnee

    2015-11-01

    The complexity of residual toxic organics from biologically treated effluents of pulp and paper mills is a serious concern. To date, it has been difficult to choose the best treatment technique because each of the available options has advantages and drawbacks. In this study, two different treatment techniques using laboratory-scale aerobic sequencing batch reactors (SBRs) were tested with the same real recycled paper mill effluent to evaluate their treatment efficiencies. Two attached-growth SBRs using granular activated carbon (GAC) with and without additional biomass and a suspended-growth SBR were used in the treatment of real recycled paper mill effluent at a chemical oxygen demand (COD) level in the range of 800-1300 mg/L, a fixed hydraulic retention time of 24 h and a COD:N:P ratio of approximately 100:5:1. The efficiency of this biological treatment process was studied over a 300-day period. The six most important wastewater quality parameters, namely, chemical oxygen demand (COD), turbidity, ammonia (expressed as NH3-N), phosphorus (expressed as PO4(3)-P), colour, and suspended solids (SS), were measured to compare the different treatment techniques. It was determined that these processes were able to almost completely and simultaneously eliminate COD (99%) and turbidity (99%); the removals of NH3-N (90-100%), PO4(3)-P (66-78%), colour (63-91%), and SS (97-99%) were also sufficient. The overall performance results confirmed that an attached-growth SBR system using additional biomass on GAC is a promising configuration for wastewater treatment in terms of performance efficiency and process stability under fluctuations of organic load. Hence, this hybrid system is recommended for the treatment of pulp and paper mill effluents. PMID:26311084

  15. String controller utilization calculating of network-attached RAID in distributed data storage system

    NASA Astrophysics Data System (ADS)

    Zhou, Ke; Zhang, JiangLing; Feng, Dan

    2003-04-01

    In the view of string controller utilization of fiber channel RAID, this paper builds SPN model of RAID and calculates the utilization of string controller in different parameters. As a conclusion: average utilization of two string controllers is higher than that of three string controllers in distributed data storage system.

  16. Evolved Mechanisms in Adolescent Anxiety and Depression Symptoms: The Role of the Attachment and Social Rank Systems

    ERIC Educational Resources Information Center

    Irons, C.; Gilbert, P.

    2005-01-01

    One hundred and forty adolescent students were assessed on measures of attachment, social rank (social comparison and submissive behaviour), and depression and anxiety symptoms. Secure attachment was significantly correlated with positive social comparison and inversely with submissive behaviour, depression and anxiety symptoms. In contrast,…

  17. Actinomyces naeslundii GroEL-dependent initial attachment and biofilm formation in a flow cell system.

    PubMed

    Arai, Toshiaki; Ochiai, Kuniyasu; Senpuku, Hidenobu

    2015-02-01

    Actinomyces naeslundii is an early colonizer with important roles in the development of the oral biofilm. The effects of butyric acid, one of short chain fatty acids in A. naeslundii biofilm formation was observed using a flow cell system with Tryptic soy broth without dextrose and with 0.25% sucrose (TSB sucrose). Significant biofilms were established involving live and dead cells in TSB sucrose with 60mM butyric acid but not in concentrations of 6, 30, 40, and 50mM. Biofilm formation failed in 60mM sodium butyrate but biofilm level in 60mM sodium butyrate (pH4.7) adjusted with hydrochloric acid as 60mM butyric media (pH4.7) was similar to biofilm levels in 60mM butyric acid. Therefore, butyric acid and low pH are required for significant biofilm formation in the flow cell. To determine the mechanism of biofilm formation, we investigated initial A. naeslundii colonization in various conditions and effects of anti-GroEL antibody. The initial colonization was observed in the 60mM butyric acid condition and anti-GroEL antibody inhibited the initial colonization. In conclusion, we established a new biofilm formation model in which butyric acid induces GroEL-dependent initial colonization of A. naeslundii resulting in significant biofilm formation in a flow system. PMID:25555820

  18. Thermoelectric generating system attached to a carburizing furnace at Komatsu Ltd., Awazu Plant

    NASA Astrophysics Data System (ADS)

    Kaibe, H.; Makino, K.; Kajihara, T.; Fujimoto, S.; Hachiuma, H.

    2012-06-01

    At the end of October 2009, KELK Ltd. started a field test of the thermoelectric generation system at a carburizing furnace of Komatsu Ltd., Awazu Plant. Residual carburizing gas based on CO, H2 and N2 is burned resulting that 20-30 kW range of flame constantly heats up the hot side of TEG. A single unit of TEG consists of 16 of the Bi-Te thermo-modules, each of which has a size of 50 × 50 × 4.2 mm3 and can generate 24W under the circumstance of 280 °C and 30 °C of hot side and cold side temperature, respectively [1]. 16 modules are separated into 4 groups and they are connected electrically depending on design concept, namely in case of focusing on reliability, parallel connection are used and in case of on simplicity and high-voltage transmission, series connection is preferably employed. The module is being life-time tested at various conditions. For instance, 10,000 of heat cycling under the hot side temperature between 250 and 50 °C with a constant cold side temperature at 30 °C gives within a few percent degrade. Both buck-and booster-type DC/DC converters controlled by one chip computer were set up and Maximum Power Point Tracking (MPPT) was well facilitated to search for the maximum output power depending on the hot and cold temperature. The electric output power from the 16 modules is summed up to charge 4 lead storage batteries (12V-65Ah) and then through DC/AC inverters electricity goes to LED light tubes inside the factory. 214 W can be generated and 180 W is delivered to the batteries.

  19. Paternal Attachment, Parenting Beliefs and Children's Attachment

    ERIC Educational Resources Information Center

    Howard, Kimberly S.

    2010-01-01

    Relationships between fathers' romantic attachment style, parenting beliefs and father-child attachment security and dependence were examined in a diverse sample of 72 fathers of young children. Paternal romantic attachment style was coded based on fathers' endorsement of a particular style represented in the Hazan and Shaver Three-Category…

  20. Tailoring the structure of hierarchically porous zeolite beta through modified orientated attachment growth in a dry gel system.

    PubMed

    Chen, Jiao; Hua, Weiming; Xiao, Yu; Huo, Qisheng; Zhu, Kake; Zhou, Xinggui

    2014-11-01

    The crystallization of zeolite beta in a dry gel system is found to follow the orientated attachment growth route, escorted with a temporal morphology change from bulky gel, through aggregation of the particulate to large zeolitic crystals. Modification of the precrystallized gel with organosilanes can be used to tune the morphology of the ultimate beta. When hexadecyltrimethoxysilane (HTS) is employed to modify precrystallized gel, a resumed secondary growth produces a hybrid mesocrystal of agglomerated nanozeolites. Combustive removal of organics leads to the formation of hierarchically porous zeolite beta of 100 to 160 nm, composed of nanocrystal building units ranging from 20 to 40 nm, with a noticeable micropore volume of 0.19 mL g(-1) and a meso/macropore size between 5 and 80 nm. Conversely, when 1,8-bis(triethoxysilyl)octane (BTO) is utilized to modify the same precrystallized gel, assemblages of discrete beta nanozeolite of around 35 nm are generated. These assemblages construct a hierarchical zeolite beta with a micropore volume of 0.20 mL g(-1) and auxiliary pores ranging from 5 to 100 nm. Both organosilanes bring about well-connected hierarchical pore networks. HTS has little effect on the Brønsted/Lewis acidity, whereas BTO causes a substantial reduction of strong Brønsted acid sites. The hierarchical beta zeolite-supported Pt catalyst exhibits improved catalytic performance for the hydroisomerization of n-heptane. PMID:25233842

  1. Biophysical Characterization of the Type III Secretion System Translocator Proteins and the Translocator Proteins Attached to Bacterium-Like Particles.

    PubMed

    Chen, Xiaotong; Choudhari, Shyamal P; Kumar, Prashant; Toth, Ronald T; Kim, Jae Hyun; Van Roosmalen, Maarten L; Leenhouts, Kees; Middaugh, C Russell; Picking, Wendy L; Picking, William D

    2015-12-01

    Diarrhea caused by Shigella, Salmonella, and Yersinia is an important public health problem, but development of safe and effective vaccines against such diseases is challenging. A new antigen delivery platform called bacterium-like particles (BLPs) was explored as a means for delivering protective antigens from the type III secretion systems (T3SS) of these pathogens. BLPs are peptidoglycan skeletons derived from Lactococcus lactis that are safe for newborns and can carry multiple antigens. Hydrophobic T3SS translocator proteins were fused to a peptidoglycan anchor (PA) for BLP attachment. The proteins and protein-BLP complexes associated with BLPs were characterized and the resulting data used to create three-index empirical phase diagrams (EPDs). On the basis of these EPDs, IpaB (Shigella) and SipB (Salmonella) behave distinctly from YopB (Yersinia) under different environmental stresses. Adding the PA domain appears to enhance the stability of both the PA and translocator proteins, which was confirmed using differential scanning calorimetry, and although the particles dominated the spectroscopic signals in the protein-loaded BLPs, structural changes in the proteins were still detected. The protein-BLPs were most stable near neutral pH, but these proteins' hydrophobicity made them sensitive to environmental stresses. PMID:26422758

  2. Bi-material attachment through a compliant interfacial system at the tendon-to-bone insertion site

    PubMed Central

    Liu, Y.X.; Thomopoulos, S.; Birman, V.; Li, J.-S.; Genin, G.M.

    2013-01-01

    The attachment of tendon to bone, one of the greatest interfacial material mismatches in nature, presents an anomaly from the perspective of interfacial engineering. Deleterious stress concentrations arising at bi-material interfaces can be reduced in engineering practice by smooth interpolation of composition, microstructure, and mechanical properties. However, following normal development, the rotator cuff tendon-to-bone “insertion site” presents an interfacial zone that is more compliant than either tendon or bone. This compliant zone is not regenerated following healing, and its absence may account for the poor outcomes observed following both natural and post-surgical healing of insertion sites such as those at the rotator cuff of the shoulder. Here, we present results of numerical simulations which provide a rationale for such a seemingly illogical yet effective interfacial system. Through numerical optimization of a mathematical model of an insertion site, we show that stress concentrations can be reduced by a biomimetic grading of material properties. Our results suggest a new approach to functional grading for minimization of stress concentrations at interfaces. PMID:24285911

  3. Ceramic blade attachment system

    DOEpatents

    Boyd, G.L.

    1995-04-11

    A retainer ring is arranged to mount turbine blades to a turbine disk so that aerodynamic forces produced by a gas turbine engine are transferred from the turbine blades to the turbine disk to cause the turbine blades and turbine disk to rotate, but so that centrifugal forces of the turbine blades resulting from the rotation of the turbine blades and turbine disk are not transferred from the turbine blades to the turbine disk. 6 figures.

  4. Ceramic blade attachment system

    DOEpatents

    Boyd, Gary L.

    1995-01-01

    A retainer ring is arranged to mount turbine blades to a turbine disk so that aerodynamic forces produced by a gas turbine engine are transferred from the turbine blades to the turbine disk to cause the turbine blades and turbine disk to rotate, but so that centrifugal forces of the turbine blades resulting from the rotation of the turbine blades and turbine disk are not transferred from the turbine blades to the turbine disk.

  5. Outcompeted by an invader? Interference and exploitative competition between tropical house gecko (Hemidactylus mabouia) and Barbados leaf-toed gecko (Phyllodactylus pulcher) for diurnal refuges in anthropogenic coastal habitats.

    PubMed

    Williams, Robert; Pernetta, Angelo P; Horrocks, Julia A

    2016-05-01

    House geckos in the genus Hemidactylus are highly successful colonizers of regions beyond their native range, with colonization often resulting in displacement of native gecko species through competitive interactions for daytime refuge (crevices) and prey resources. We report on data collected from nighttime surveys undertaken in April-May 2014 on Barbados, West Indies, that focused on the distribution and abundance of the endemic Barbados leaf-toed gecko (Phyllodactylus pulcher) and the introduced tropical house gecko (Hemidactylus mabouia) along unlit coastal walls and among boulders in the grounds of a hotel resort. In contrast to patterns of displacement of native species by H. mabouia seen elsewhere, P. pulcher was more abundant than H. mabouia on coastal walls, whereas the latter was found in greater numbers using boulders at this site. Walls and boulders differed with regard to availability of diurnal refugia suitable for geckos, with the walls having high frequency of small crevices with openings <20 mm, and boulders offering very little cover other than the underside of the boulder itself. To investigate whether this niche separation was a result of differences in diurnal refuge use between the species, we conducted experimental trials in which geckos were allowed to select between refugia with different characteristics. Both species selected for narrower and warmer refugia, and refugia that had been previously occupied by the other species. These shared preferences for refugia type suggest that other factors underlie the niche separation observed in the field. In supporting high densities of P. pulcher, coastal walls could offer important secondary habitat by augmenting the natural cliff side habitat of this endemic gecko, a finding that could be exploited for the conservation of this candidate species for Critically Endangered classification. PMID:26923791

  6. Reactive oxygen species generated from skeletal muscles are required for gecko tail regeneration.

    PubMed

    Zhang, Qing; Wang, Yingjie; Man, Lili; Zhu, Ziwen; Bai, Xue; Wei, Sumei; Liu, Yan; Liu, Mei; Wang, Xiaochuan; Gu, Xiaosong; Wang, Yongjun

    2016-01-01

    Reactive oxygen species (ROS) participate in various physiological and pathological functions following generation from different types of cells. Here we explore ROS functions on spontaneous tail regeneration using gecko model. ROS were mainly produced in the skeletal muscle after tail amputation, showing a temporal increase as the regeneration proceeded. Inhibition of the ROS production influenced the formation of autophagy in the skeletal muscles, and as a consequence, the length of the regenerating tail. Transcriptome analysis has shown that NADPH oxidase (NOX2) and the subunits (p40(phox) and p47(phox)) are involved in the ROS production. ROS promoted the formation of autophagy through regulation of both ULK and MAPK activities. Our results suggest that ROS produced by skeletal muscles are required for the successful gecko tail regeneration. PMID:26853930

  7. Investigation of bioinspired gecko fibers to improve adhesion of HeartLander surgical robot.

    PubMed

    Tortora, Giuseppe; Glass, Paul; Wood, Nathan; Aksak, Burak; Menciassi, Arianna; Sitti, Metin; Riviere, Cameron

    2012-01-01

    HeartLander is a medical robot proposed for minimally invasive epicardial intervention on the beating heart. To date, all prototypes have used suction to gain traction on the epicardium. Gecko-foot-inspired micro-fibers have been proposed for repeatable adhesion to surfaces. In this paper, a method for improving the traction of HeartLander on biological tissue is presented. The method involves integration of gecko-inspired fibrillar adhesives on the inner surfaces of the suction chambers of HeartLander. Experiments have been carried out on muscle tissue ex vivo assessing the traction performance of the modified HeartLander with bio-inspired adhesive. The adhesive fibers are found to improve traction on muscle tissue by 57.3 %. PMID:23366040

  8. Reactive oxygen species generated from skeletal muscles are required for gecko tail regeneration

    PubMed Central

    Zhang, Qing; Wang, Yingjie; Man, Lili; Zhu, Ziwen; Bai, Xue; Wei, Sumei; Liu, Yan; Liu, Mei; Wang, Xiaochuan; Gu, Xiaosong; Wang, Yongjun

    2016-01-01

    Reactive oxygen species (ROS) participate in various physiological and pathological functions following generation from different types of cells. Here we explore ROS functions on spontaneous tail regeneration using gecko model. ROS were mainly produced in the skeletal muscle after tail amputation, showing a temporal increase as the regeneration proceeded. Inhibition of the ROS production influenced the formation of autophagy in the skeletal muscles, and as a consequence, the length of the regenerating tail. Transcriptome analysis has shown that NADPH oxidase (NOX2) and the subunits (p40phox and p47phox) are involved in the ROS production. ROS promoted the formation of autophagy through regulation of both ULK and MAPK activities. Our results suggest that ROS produced by skeletal muscles are required for the successful gecko tail regeneration. PMID:26853930

  9. The mitochondrial genome of the gold-dust day gecko, Phelsuma laticauda (Sauria, Gekkota, Gekkonidae).

    PubMed

    Yan, Jie; Tian, Chao; Bauer, Aaron M; Zhou, Kaiya

    2016-01-01

    We sequenced the nearly complete mitochondrial genome of the gold-dust day gecko, Phelsuma laticauda, which is native to northern Madagascar. The mitogenome is 15,416 bp in size, consisting of 37 genes coding for 13 proteins, 22 tRNAs, and 2 rRNAs. Due to the unsuccessful sequencing of the control region, the length is relatively shorter than that of other gekkonids. The gene organization conforms to the vertebrate consesus gene arrangement. PMID:24438276

  10. Electrocardiogram, heart movement and heart rate in the awake gecko (Hemidactylus mabouia).

    PubMed

    Germer, Carina M; Tomaz, Juliana M; Carvalho, Ana F; Bassani, Rosana A; Bassani, José W M

    2015-01-01

    The electrocardiogram (ECG) is the simplest and most effective non-invasive method to assess the electrical activity of the heart and to obtain information on the heart rate (HR) and rhythm. Because information on the HR of very small reptiles (body mass <10 g) is still scarce in the literature, in the present work we describe a procedure for recording the ECG in non-anesthetized geckos (Hemidactylus mabouia, Moreau de Jonnès, 1818) under different conditions, namely manual restraint (MR), spontaneous tonic immobility (TI), and in the non-restrained condition (NR). In the gecko ECG, the P, QRS and T waves were clearly distinguishable. The HR was 2.83 ± 0.02 Hz under MR, which was significantly greater (p < 0.001) than the HR under the TI (1.65 ± 0.09 Hz) and NR (1.60 ± 0.10 Hz) conditions. Spontaneously beating isolated gecko hearts contracted at 0.84 ± 0.03 Hz. The in vitro beating rate was affected in a concentration-dependent fashion by adrenoceptor stimulation with noradrenaline, as well as by the muscarinic cholinergic agonist carbachol, which produced significant positive and negative chronotropic effects, respectively (p < 0.001). To our knowledge, this is the first report on the ECG morphology and HR values in geckos, particularly under TI. The methodology and instrumentation developed here are useful for non-invasive in vivo physiological and pharmacological studies in small reptiles without the need of physical restraint or anesthesia. PMID:25395252

  11. High Diversity of Hepatozoon spp. in Geckos of the Genus Tarentola.

    PubMed

    Tomé, Beatriz; Rato, Catarina; Harris, D James; Perera, Ana

    2016-08-01

    :   Hemogregarines are the most-commonly reported hemoparasites in reptiles. In this work we analyzed samples from 572 individuals of 6 species of the wall gecko genus Tarentola from European and African countries adjacent to the Mediterranean Sea as well as from the Macaronesian islands. Screening was done using hemogregarine-specific primers for the 18S rRNA gene. Positive amplifications were sequenced so that the diversity of the hemogregarines from these hosts could be assessed within a phylogenetic framework. The results from the phylogenetic analysis showed that within Tarentola, the detected parasites are comprised of at least 4 distinct main lineages of Hepatozoon spp. In clades A and B, the new sequences clustered closely together with the ones previously known from individuals of the genus Tarentola and other species of geckos but also with those from other vertebrate host groups including skinks, snakes, iguanids, and rodents. Clade C included a sample from Tarentola angustimentalis of the Canary Islands. This sequence is the first molecular characterization of these hemogregarines in this archipelago. Until now, this lineage had only been found in lacertids, skinks, and snakes, so this infection extends the host range for this clade. Lastly, in the newly detected clade D, the retrieved parasite sequences form a group currently identified as exclusive of geckos. Our results show that geckos of Tarentola spp. harbor a great diversity of hemogregarines but also that further sampling and other tools, including a multi-locus approach using faster-evolving genetic markers, and identification of definitive hosts are needed to better understand the biology, diversity, and distribution of these parasites. PMID:26835601

  12. Effects of spatial subsidies and habitat structure on the foraging ecology and size of geckos

    USGS Publications Warehouse

    Briggs, Amy A.; Young, Hillary S.; McCauley, Douglas J.; Hathaway, Stacie A.; Dirzo, Rodolfo; Fisher, Robert N.

    2012-01-01

    While it is well established that ecosystem subsidies—the addition of energy, nutrients, or materials across ecosystem boundaries—can affect consumer abundance, there is less information available on how subsidy levels may affect consumer diet, body condition, trophic position, and resource partitioning among consumer species. There is also little information on whether changes in vegetation structure commonly associated with spatial variation in subsidies may play an important role in driving consumer responses to subsidies. To address these knowledge gaps, we studied changes in abundance, diet, trophic position, size, and body condition of two congeneric gecko species (Lepidodactylus spp.) that coexist in palm dominated and native (hereafter dicot dominated) forests across the Central Pacific. These forests differ trongly both in the amount of marine subsidies that they receive from seabird guano and carcasses, and in the physical structure of the habitat. Contrary to other studies, we found that subsidy level had no impact on the abundance of either gecko species; it also did not have any apparent effects on resource partitioning between species. However, it did affect body size, dietary composition, and trophic position of both species. Geckos in subsidized, dicot forests were larger, had higher body condition and more diverse diets, and occupied a much higher trophic position than geckos found in palm dominated, low subsidy level forests. Both direct variation in subsidy levels and associated changes in habitat structure appear to play a role in driving these responses. These results suggest that variation in subsidy levels may drive important behavioral responses in predators, even when their numerical response is limited. Strong changes in trophic position of consumers also suggest that subsidies may drive increasingly complex food webs, with longer overall food chain length.

  13. The pKa of the protonated Schiff bases of gecko cone and octopus visual pigments.

    PubMed Central

    Liang, J; Steinberg, G; Livnah, N; Sheves, M; Ebrey, T G; Tsuda, M

    1994-01-01

    A visual pigment is composed of retinal bound to its apoprotein by a protonated Schiff base linkage. Light isomerizes the chromophore and eventually causes the deprotonation of this Schiff base linkage at the meta II stage of the bleaching cycle. The meta II intermediate of the visual pigment is the active form of the pigment that binds to and activates the G protein transducin, starting the visual cascade. The deprotonation of the Schiff base is mandatory for the formation of meta II intermediate. We studied the proton binding affinity, pKa, of the Schiff base of both octopus rhodopsin and the gecko cone pigment P521 by spectral titration. Several fluorinated retinal analogs have strong electron withdrawing character around the Schiff base region and lower the Schiff base pKa in model compounds. We regenerated octopus and gecko visual pigments with these fluorinated and other retinal analogs. Experiments on these artificial pigments showed that the spectral changes seen upon raising the pH indeed reflected the pKa of the Schiff base and not the denaturation of the pigment or the deprotonation of some other group in the pigment. The Schiff base pKa is 10.4 for octopus rhodopsin and 9.9 for the gecko cone pigment. We also showed that although the removal of Cl- ions causes considerable blue-shift in the gecko cone pigment P521, it affects the Schiff base pKa very little, indicating that the lambda max of visual pigment and its Schiff base pKa are not tightly coupled. PMID:7948697

  14. Effect of abutment angulation in the retention and durability of three overdenture attachment systems: An in vitro study

    PubMed Central

    Ustrell, Raul; Mendes, Jose Manuel; Braga, Ana Cristina; Berastegui, Esther

    2016-01-01

    PURPOSE This in vitro study investigated and compared the durability and retention of three types of attachments. MATERIALS AND METHODS Three commercially available attachments were investigated: Clix®, Dalbo-Plus® and Locator®. In total, 72 samples of these attachments were placed in the acrylic resin forms and subjected to mechanical testing (5400 cycles of insertion and removal) over the respective ball or Locator abutments immersed in artificial saliva at pH 7 and 37℃. The abutments were placed at angulations of 0°, 10° and 20°. The retention force was recorded at the beginning and after 540, 1080, 2160, 3240, 4320 and 5400 insertion-removal cycles. RESULTS The results revealed that there were significant differences in the average values of the insertion/removal force due to angulation (F (2.48) = 343619, P<.05) and the type of attachment (F (7.48) = 23.220, P<.05). CONCLUSION Greater angulation of the abutments was found to influence the retention capacity of the attachments, and the fatigue test simulating 5 years of denture insertion and removal did not produce wear in the metal abutments. PMID:26949484

  15. Applicability of linearized-theory attached-flow methods to design and analysis of flap systems at low speeds for thin swept wings with sharp leading edges

    NASA Technical Reports Server (NTRS)

    Carlson, Harry W.; Darden, Christine M.

    1987-01-01

    Low-speed experimental force and data on a series of thin swept wings with sharp leading edges and leading and trailing-edge flaps are compared with predictions made using a linearized-theory method which includes estimates of vortex forces. These comparisons were made to assess the effectiveness of linearized-theory methods for use in the design and analysis of flap systems in subsonic flow. Results demonstrate that linearized-theory, attached-flow methods (with approximate representation of vortex forces) can form the basis of a rational system for flap design and analysis. Even attached-flow methods that do not take vortex forces into account can be used for the selection of optimized flap-system geometry, but design-point performance levels tend to be underestimated unless vortex forces are included. Illustrative examples of the use of these methods in the design of efficient low-speed flap systems are included.

  16. Attachment Representation of Institutionalized Children in Japan

    ERIC Educational Resources Information Center

    Katsurada, Emiko

    2007-01-01

    This exploratory study represents one of the first attachment investigations of Japanese children who have been institutionalized. Mental representation of attachment was assessed using George and Solomon's (1990, 1996, 2000) Attachment Doll Play Classification System of the Bretherton et al. (1990) doll play story stems. Participants were 32…

  17. Preparation and properties of polyurethane/silicone materials for biomimetic gecko setae

    NASA Astrophysics Data System (ADS)

    Yu, Min; Dai, Zhendong; Yang, Shengrong

    2014-03-01

    In the biomimetic design of gecko setae, it is necessary to select materials with appropriate adhesive properties and to understand the effects of materials on normal and tangential adhesive forces. To meet the adhesion performance requirements of the biomimetic gecko robot foot, in this study, performance-improved polyurethane/silicone polymer materials were designed and synthesized, and the normal adhesion and tangential adhesion were measured using an adhesive friction comprehensive tester. The results show that normal adhesion increased with an increase in load when the normal load is small; when the normal load exceeds a critical value, the increase in normal adhesion slows and adhesion saturates. Under the condition of an adhesive state, the tangential adhesive force was larger for a smaller negative normal force, and a relatively large tangential adhesive force could be generated with a very small negative normal force. The elastic modulus of the synthetic polyurethane/silicone material varied with varying ratios of components, and it increased with increasing urethane content. Polyurethane/silicone material with about 30% polyurethane provided greater adhesion than other materials with different contents of polyurethane. The results provide a basis for the choice of biomimetic materials of the biomimetic gecko robot foot.

  18. Mechanisms of spectral tuning in the RH2 pigments of Tokay gecko and American chameleon

    PubMed Central

    Takenaka, Naomi; Yokoyama, Shozo

    2009-01-01

    At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 pigments of nocturnal Tokay gecko (Gekko gekko) and diurnal American chameleon (Anolis carolinensis) as well as chimeras between them. The RH2 pigments of the gecko and chameleon reconstituted with 11-cis-retinal had the wavelengths of maximal absorption (λmax’s) of 467 and 496 nm, respectively. Chimeric pigment analyses indicated that 76–86%, 14–24%, and 10% of the spectral difference between them could be explained by amino acid differences in transmembrane (TM) helices I~IV, V~VII, and amino acid interactions between the two segments, respectively. Evolutionary and mutagenesis analyses revealed that the λmax’s of the gecko and chameleon pigments diverged from each other not only by S49A (serine to alanine replacement at residue 49), S49F (serine to phenylalanine), L52M (leucine to methionine), D83N (aspartic acid to asparagine), M86T (methionine to thereonine), and T97A (threonine to alanine) but also by other amino acid replacements that cause minor λmax-shifts individually. PMID:17590287

  19. Temperature, field activity and post-feeding metabolic response in the Asian house gecko, Hemidactylus frenatus.

    PubMed

    Lei, Juan; Booth, David T

    2014-10-01

    Temperature has significant effects on physiological activities and geographical distribution of ectotherms. The Asian house gecko Hemidactylus frenatus has become one of the most widely distributed reptiles in the world and is an invasive species in Australia. Since being introduced into northern Australia, Asian house geckos have spread rapidly and expanded into south-east Queensland and northern New South Wales. Despite their rapid spread, there have been few studies that address thermal adaptability of this species. In order to understand how temperature might limit the distribution and feeding behavior of H. frenatus we observed gecko foraging activities in the wild over the winter period, measured the temperature at which voluntary feeding ceases, and assessed the effect of temperature (30, 25, 20, and 18 °C) on post-feeding metabolic rate. Resting metabolic rate and post-feeding peak in metabolic rate decreased with low temperature, while the duration of elevated metabolic rate after feeding increased at lower temperature. The SDA coefficient (a ratio of the energy expended due to the post-feeding rise in metabolic rate to the energy contained within the meal) did not change systematically with ambient temperature. Field observations and voluntary feeding experiments showed that H. frenatus stop feeding when ambient temperature drops below 17 °C, so that persistent night time temperatures below 17 °C may be limiting the distribution of this species. PMID:25436968

  20. The embryology of the retinal pigmented epithelium in dwarf geckos (Gekkota: Sphaerodactylinae): a unique developmental pattern

    PubMed Central

    2014-01-01

    Background The retinal pigmented epithelium (RPE) is a rounded shaped structure in almost all lizards. In the New World dwarf geckos, this structure shows an unusual morphology. In addition to this ocular character, we describe notable differences in the development of these geckos in comparison with available developmental staging tables for other geckos and squamate reptiles. Results We identified two main patterns of development of the RPE for squamates. These patterns were mapped onto a metatree of concordant hypotheses of squamates based on molecular data. During post-ovopositional stages the representative species of sphaerodactyls exhibit a RPE layer that transforms gradually from an ovoid form into the generalized spherical form. Sphaerodactyls are the only group of squamates in which this pattern is known. Conclusions This transition might be circumstantial evidence that the accessory RPE plays a role in providing additional protection for their apomorphic concaviclivate temporal fovea. We also report the presence of conjunctival papillae in a developmental stage prior to the formation of scleral ossicles. This developmental progression is similar to that of birds and turtles. PMID:24974837

  1. The Role of Surface Chemistry in Adhesion and Wetting of Gecko Toe Pads

    NASA Astrophysics Data System (ADS)

    Badge, Ila; Stark, Alyssa Y.; Paoloni, Eva L.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2014-10-01

    An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70-90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties.

  2. The Role of Surface Chemistry in Adhesion and Wetting of Gecko Toe Pads

    PubMed Central

    Badge, Ila; Stark, Alyssa Y.; Paoloni, Eva L.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2014-01-01

    An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70–90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties. PMID:25323067

  3. The role of surface chemistry in adhesion and wetting of gecko toe pads.

    PubMed

    Badge, Ila; Stark, Alyssa Y; Paoloni, Eva L; Niewiarowski, Peter H; Dhinojwala, Ali

    2014-01-01

    An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70-90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties. PMID:25323067

  4. Understanding and promoting attachment.

    PubMed

    Wilson, Samantha L

    2009-08-01

    Interest in early relationships has led to increased use of terms such as attachment disorder, attachment problems, and attachment therapy when describing behavioral/emotional regulation in young children. Unfortunately, such terms are vague and lead to clinical confusion and diagnostic inaccuracies. This article will introduce attachment theory, with a discussion of reactive attachment disorder and implications for treatment of children who have problems with social-emotional development. PMID:19681518

  5. Development of a strain/temperature gauge and attachment system for use on carbon composites at elevated temperature

    NASA Astrophysics Data System (ADS)

    Lanius, S. J.; Brasfield, R. G.; Wnuk, S. P.

    1987-03-01

    The difficulties encountered when instrumenting solid rocket motors for acquiring strain data are reviewed, emphasizing the strong temperature dependence due to apparent strain effects. The development of a strain/temperature gage to overcome some of these problems is discussed. This gage is designed to produce low apparent strain when attached to a carbon-carbon substrate. Characterization and performance data for gages attached with ceramic cement to carbon-carbon tensile coupons are presented, and the effect of a flame-sprayed installation process is discussed.

  6. Oxytocin enhances the experience of attachment security.

    PubMed

    Buchheim, Anna; Heinrichs, Markus; George, Carol; Pokorny, Dan; Koops, Eva; Henningsen, Peter; O'Connor, Mary-Frances; Gündel, Harald

    2009-10-01

    Repeated interactions between infant and caregiver result in either secure or insecure relationship attachment patterns, and insecure attachment may affect individual emotion-regulation and health. Given that oxytocin enhances social approach behavior in animals and humans, we hypothesized that oxytocin might also promote the subjective experience of attachment security in humans. Within a 3-week interval, 26 healthy male students classified with an insecure attachment pattern were invited twice to an experimental session. At the beginning of each experiment, a single dose of oxytocin or placebo was administered intranasally, using a double-blind, placebo-controlled within-subject design. In both conditions, subjects completed an attachment task based on the Adult Attachment Projective Picture System (AAP). Thirty-two AAP picture system presentations depicted attachment-related events (e.g. illness, solitude, separation, and loss), and were each accompanied by four prototypical phrases representing one secure and three insecure attachment categories. In the oxytocin condition, a significant proportion of these insecure subjects (N=18; 69%) increased in their rankings of the AAP prototypical "secure attachment" phrases and decreased in overall ranking of the "insecure attachment" phrases. In particular, there was a significant decrease in the number of subjects ranking the pictures with "insecure-preoccupied" phrases from the placebo to the oxytocin condition. We find that a single dose of intranasally administered oxytocin is sufficient to induce a significant increase in the experience of attachment security in insecurely attached adults. PMID:19457618

  7. Social attachments and traumatic stress

    PubMed Central

    Bryant, Richard A.

    2016-01-01

    The extent to which we engage with our social world has been central to our survival as a species and, accordingly, is relevant to how we cope with trauma and adversity. This review summarises current knowledge about the importance of social connections from an evolutionary perspective, as well as integrating this with a discussion of prevailing attachment theories. Experimental research supporting the potential benefit of attachments for managing adversity are presented, along with a review of how these benefits are moderated by individual differences in attachment style. The potential impact of trauma on attachment systems, and the manner in which this can compound trauma stress is discussed. Finally, a broader overview of social network analysis is introduced and it is proposed that a more sociocentric framework of trauma response would promote a fuller understanding of how social processes moderate trauma response. PMID:26996531

  8. Aquatic versus terrestrial attachment: Water makes a difference.

    PubMed

    Ditsche, Petra; Summers, Adam P

    2014-01-01

    Animal attachment to a substrate is very different in terrestrial and aquatic environments. We discuss variations in both the forces acting to detach animals and forces of attachment. While in a terrestrial environment gravity is commonly understood as the most important detachment force, under submerged conditions gravity is nearly balanced out by buoyancy and therefore matters little. In contrast, flow forces such as drag and lift are of higher importance in an aquatic environment. Depending on the flow conditions, flow forces can reach much higher values than gravity and vary in magnitude and direction. For many of the attachment mechanisms (adhesion including glue, friction, suction and mechanical principles such as hook, lock, clamp and spacer) significant differences have to be considered under water. For example, the main principles of dry adhesion, van der Waals forces and chemical bonding, which make a gecko stick to the ceiling, are weak under submerged conditions. Capillary forces are very important for wet adhesion, e.g., in terrestrial beetles or flies, but usually do not occur under water. Viscous forces are likely an important contributor to adhesion under water in some mobile animals such as torrent frogs and mayflies, but there are still many open questions to be answered. Glue is the dominant attachment mechanism of sessile aquatic animals and the aquatic realm presents many challenges to this mode of attachment. Viscous forces and the lack of surface tension under submerged conditions also affect frictional interactions in the aquatic environment. Moreover, the limitation of suction to the pressure difference at vacuum conditions can be ameliorated under water, due to the increasing pressure with water depth. PMID:25671138

  9. Aquatic versus terrestrial attachment: Water makes a difference

    PubMed Central

    Summers, Adam P

    2014-01-01

    Summary Animal attachment to a substrate is very different in terrestrial and aquatic environments. We discuss variations in both the forces acting to detach animals and forces of attachment. While in a terrestrial environment gravity is commonly understood as the most important detachment force, under submerged conditions gravity is nearly balanced out by buoyancy and therefore matters little. In contrast, flow forces such as drag and lift are of higher importance in an aquatic environment. Depending on the flow conditions, flow forces can reach much higher values than gravity and vary in magnitude and direction. For many of the attachment mechanisms (adhesion including glue, friction, suction and mechanical principles such as hook, lock, clamp and spacer) significant differences have to be considered under water. For example, the main principles of dry adhesion, van der Waals forces and chemical bonding, which make a gecko stick to the ceiling, are weak under submerged conditions. Capillary forces are very important for wet adhesion, e.g., in terrestrial beetles or flies, but usually do not occur under water. Viscous forces are likely an important contributor to adhesion under water in some mobile animals such as torrent frogs and mayflies, but there are still many open questions to be answered. Glue is the dominant attachment mechanism of sessile aquatic animals and the aquatic realm presents many challenges to this mode of attachment. Viscous forces and the lack of surface tension under submerged conditions also affect frictional interactions in the aquatic environment. Moreover, the limitation of suction to the pressure difference at vacuum conditions can be ameliorated under water, due to the increasing pressure with water depth. PMID:25671138

  10. Electron attachment to fluorocarbon radicals

    NASA Astrophysics Data System (ADS)

    Shuman, Nicholas

    2014-10-01

    Most plasma environments contain populations of short-lived species such as radicals, the chemistry of which can have significant effects on the overall chemistry of the system. However, few experimental measurements of the kinetics of electron attachment to radicals exist due to the inherent difficulties of working with transient species. Calculations from first principles have been attempted, but are arduous and, because electron attachment is so sensitive to the specifics of the potential surface, their accuracy has not been established. Electron attachment to small fluorocarbon radicals is particularly important, as the data are needed for predictive modeling of plasma etching of semiconductor materials, a key process in the industrial fabrication of microelectronics. We have recently developed a novel flowing afterglow technique to measure several types of otherwise difficult to study plasma processes, including thermal electron attachment to radicals. Variable Electron and Neutral Density Attachment Mass Spectrometry (VENDAMS) exploits dissociative electron attachment in a weakly ionized plasma as a radical source. Here, we apply VENDAMS to a series of halofluorocarbon precursors in order to measure the kinetics of thermal electron attachment to fluorocarbon radicals. Results are presented for CF2, CF3, C2F5,C2F3,1-C3F7, 2-C3F7, and C3F5 from 300 K to 900 K. Both the magnitude and the temperature dependences of rate coefficients as well as product branching between associative and dissociative attachment are highly system specific; however, thermal attachment to all species is inefficient, never exceeding 5% of the collision rate. The data are analyzed using a recently developed kinetic modeling approach, which uses extended Vogt-Wannier theory as a starting point, accounts for dynamic effects such as coupling between the electron and nuclear motions through empirically validated functional forms, and finally uses statistical theory to determine the fate of

  11. Special Attachments. Module 19.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on special attachments, one in a series dealing with industrial sewing machines, their attachments, and operation, covers four topics: gauges; cording attachment; zipper foot; and hemming, shirring, and binding. For each topic these components are provided: an introduction, directions, an objective, learning activities, student…

  12. Adolescent Attachment and Psychopathology.

    ERIC Educational Resources Information Center

    Rosenstein, Diana S.; Horowitz, Harvey A.

    1996-01-01

    In relationships among attachment classification, psychopathology, and personality, traits were examined in a group of 60 psychiatrically hospitalized adolescents. Attachment was examined in 27 adolescent-mother pairs. Both adolescent and maternal attachment status were overwhelmingly insecure and were highly concordant. Results support a model of…

  13. A new species of arboreal forest-dwelling gecko (Hemidactylus: Squamata: Gekkonidae) from coastal Kenya, East Africa.

    PubMed

    Malonza, Patrick K; Bauer, Aaron M

    2014-01-01

    A new species of Hemidactylus, H. mrimaensis sp. nov., is described from coastal kaya forests of Kenya. This small-sized, arboreal gecko may be distinguished from its probable close relative, the sympatric H. mabouia, by its more slender habitus, golden color, small adult body length (maximum SVL 50 mm in females) and features of scalation including keeled dorsal tubercles in 11-14 longitudinal rows, pointed tubercles on tail larger than those on the dorsum, and 32-34 precloacal pores in males. This gecko may be endemic to the coastal forests and given the ongoing threats to this habitat, the species is of high conservation concern. PMID:24869535

  14. Magnetic attachment mechanism

    NASA Technical Reports Server (NTRS)

    Harwell, William D. (Inventor); Wu, Mitchell B. (Inventor)

    1990-01-01

    A magnetic attachment mechanism adapted for interfacing with the manipulator arm (11) of a remote manipulator system and comprising a pair of permanent magnets (31,32) of rare earth material which are arranged in a stator-rotor relationship. The rotor magnet (32), is journalled for rotation about its longitudinal axis between pole plates (35,36) of the stator magnet (31), each of which includes an adhering surface (35a,36a). In a first rotary position corresponding to the ON condition, each of the poles of the rotor magnet (32) is closely adjacent a stator magnet pole plate of like polarity whereby the respective magnet fields are additive for producing a strong magnetic field emanating from the adhering surfaces (35a,36a) for attracting a ferrous magnetic plate 20, or the like, affixed to the payload (20 or 50). When the rotor magnet (32) is rotated to a second position corresponding to the OFF condition, each of the poles of the rotor magnet (31) is disposed closely adjacent a pole plate of unlike polarity whereby the magnetic fields of the magnets are in cancelling relationship at the adhering surfaces (35a,36a) which permits the release of a payload. An actuator (51 or 70) for selectively rotating the rotor magnet (32) between the ON and OFF positions is provided for interfacing and connecting the magnetic attachment mechanism with a manipulator arm. For effecting an optimal rigidized attachment the payload is provided with guides (91,92) cooperable with guides (96,16,17) on the housing of the mechanism for directing adhering surfaces (35a,36a) of the polar plates to the ferrous plate (20).

  15. Contaminant adhesion (aerial/ground biofouling) on the skin of a gecko.

    PubMed

    Watson, Gregory S; Cribb, Bronwen W; Schwarzkopf, Lin; Watson, Jolanta A

    2015-07-01

    In this study, we have investigated the micro- and nano-structuring and contaminant adhesional forces of the outer skin layer of the ground dwelling gecko--Lucasium steindachneri. The lizard's skin displayed a high density of hairs with lengths up to 4 μm which were spherically capped with a radius of curvature typically less than 30 nm. The adhesion of artificial hydrophilic (silica) and hydrophobic (C18) spherical particles and natural pollen grains were measured by atomic force microscopy and demonstrated extremely low values comparable to those recorded on superhydrophobic insects. The lizard scales which exhibited a three-tier hierarchical architecture demonstrated higher adhesion than the trough regions between scales. The two-tier roughness of the troughs comprising folding of the skin (wrinkling) limits the number of contacting hairs with particles of the dimensions used in our study. The gecko skin architecture on both the dorsal and trough regions demonstrates an optimized topography for minimizing solid-solid and solid-liquid particle contact area, as well as facilitating a variety of particulate removal mechanisms including water-assisted processes. These contrasting skin topographies may also be optimized for other functions such as increased structural integrity, levels of wear protection and flexibility of skin for movement and growth. While single hair adhesion is low, contributions of many thousands of individual hairs (especially on the abdominal scale surface and if deformation occurs) may potentially aid in providing additional adhesional capabilities (sticking ability) for some gecko species when interacting with environmental substrates such as rocks, foliage and even man-made structuring. PMID:26063826

  16. Adherence to Bergmann's rule by lizards may depend on thermoregulatory mode: support from a nocturnal gecko.

    PubMed

    Penniket, Sophie; Cree, Alison

    2015-06-01

    Bergmann's rule predicts an increase in body size with decreasing environmental temperature; however, the converse pattern has been found in the majority of lizards studied to date. For these ectotherms, small body size may provide thermal benefits (rapid heat uptake when basking), which would be highly advantageous in cold environments. Yet such an advantage may not exist in nocturnal lizards (which do not avidly bask), in which Bergmann's rule has not been closely studied. We have examined whether the body size of a primarily nocturnal gecko, Woodworthia "Otago/Southland" changed with elevation and operative temperature (determined using physical copper models). In a laboratory study, we investigated whether thermoregulatory mode (heliothermy or thigmothermy) alters the effect of body size on heating and cooling rates. This gecko followed Bergmann's rule, thereby showing the opposite of the dominant pattern in diurnal lizards. Size at maturity, maximum size of adults and size at birth were larger at higher elevations and at lower operative temperatures. Using physical models, we found that large body size can confer thermal benefits for nocturnal lizards that remain within diurnal retreats. Bergmann's rule should not be dismissed for all lizards. Our results clearly support Bergmann's rule for at least one thigmothermic species, for which large body size may provide thermal benefits. Future studies on Bergmann's rule in lizards should consider thermoregulatory mode. We advocate that this ecogeographic rule be examined in relation to operative temperature measured at field sites. Finally, we predict that climate warming may weaken the relationship between body size and elevation in this gecko. PMID:25663371

  17. Effects of testosterone on sexual behavior and morphology in adult female leopard geckos, Eublepharis macularius.

    PubMed

    Rhen, T; Ross, J; Crews, D

    1999-10-01

    The leopard gecko, Eublepharis macularius, is a species in which testosterone (T) is the primary circulating sex hormone in adults of both sexes. There are, however, sex differences in T physiology. Whereas males have prolonged periods with high T levels, T levels cycle in accord with follicular development in females. Specifically, T concentration increases during vitellogenesis, drops after ovulation, and then remains at previtellogenic levels until eggs are laid and the next follicular cycle begins. To determine the function of T in females, we manipulated both the level and the duration of T elevation using Silastic implants in intact, adult female leopard geckos. Females had low ( approximately 1 ng/ml), medium ( approximately 100 ng/ml), or high ( approximately 200 ng/ml) T levels for either a short (8 days) or a long (35 days) duration. Behavior tests with males were conducted on days 1-5 in the short-duration group or on days 29-33 in the long-duration group. For both short- and long-duration groups, T treatment decreased attractivity in females with medium and high T levels compared to females with low T levels. In contrast, females with a medium T level were more receptive than females with a low T level in the short-duration group. Females in the long-duration group were unreceptive regardless of T level. Females treated for a long duration also displayed more aggression toward and evoked more aggression from males than short duration females. Short-duration T treatment had no masculinizing effect on female morphology, whereas medium and high T levels for a long duration induced development of hemipenes. Overall, these results suggest that T can both increase and decrease sexual behaviors in the female leopard gecko. PMID:10506536

  18. Organization and activation of sexual and agonistic behavior in the leopard gecko, Eublepharis macularius.

    PubMed

    Rhen, T; Crews, D

    2000-04-01

    Gonadal sex is determined by the temperature experienced during incubation in the leopard gecko (Eublepharis macularius). Furthermore, both factors, incubation temperature and gonadal sex, influence adult sexual and agonistic behavior in this species. Yet it is unclear whether such differences in behavior are irreversibly organized during development or are mediated by differences in hormone levels in adulthood. To address this question, we gonadectomized adult females and males generated from a female-biased (30 degrees C) and a male-biased (32.5 degrees C) incubation temperature and treated them with equivalent levels of various sex steroids. We found that 17beta-estradiol (E(2)) activated sexual receptivity in females but not males, suggesting an organized sex difference in behavioral sensitivity to E(2). There were also organized and activated sex differences in attractivity to stimulus males. Although females were more attractive than males when treated with E(2), both sexes were equally unattractive when treated with dihydrotestosterone (DHT) or testosterone (T). Likewise, sex differences in aggressive and submissive behavior were organized and activated. Attacks on stimulus males were activated by T in males but not in females. In contrast, hormones did not influence flight behavior in males but did affect female submissiveness. Overall, males also evoked more attacks by stimulus males than did females. Nevertheless, females and males treated with androgens evoked more attacks than animals of the same sex that were treated with cholesterol or E(2). Incubation temperature had some weak effects on certain behaviors and no effect on others. This suggests that temperature effects in gonadally intact geckos may be due primarily to differences in circulating levels of hormones in adulthood. We conclude that gonadal sex has both organizational and activational effects on various behaviors in the leopard gecko. PMID:10773745

  19. Neurobiology of infant attachment.

    PubMed

    Moriceau, Stephanie; Sullivan, Regina M

    2005-11-01

    A strong attachment to the caregiver is critical for survival in altricial species, including humans. While some behavioral aspects of attachment have been characterized, its neurobiology has only recently received attention. Using a mammalian imprinting model, we are assessing the neural circuitry that enables infant rats to attach quickly to a caregiver, thus enhancing survival in the nest. Specifically, the hyper-functioning noradrenergic locus coeruleus (LC) enables pups to learn rapid, robust preference for the caregiver. Conversely, a hypo-functional amygdala appears to prevent the infant from learning aversions to the caregiver. Adult LC and amygdala functional emergence correlates with sensitive period termination. This study suggests the neonatal brain is not an immature version of the adult brain but is uniquely designed to optimize attachment to the caregiver. Although human attachment may not rely on identical circuitry, the work reviewed here suggests a new conceptual framework in which to explore human attachments, particularly attachments to abusive caregivers. PMID:16252291

  20. A new species of gecko from arid inland regions of eastern Australia (Diplodactylus; Diplodactylidae).

    PubMed

    Couper, Patrick J; Oliver, Paul M

    2016-01-01

    We describe a new species of small terrestrial gecko in the genus Diplodactylus from inland regions of western Queensland and New South Wales, Australia. Diplodactylus ameyi sp. nov. can be distinguished from its congeners in the Diplodactylus conspicillatus species-group by its relatively large size, bulbous tail which lacks an acute attenuated extension at tip, small first labial scale and comparatively robust head morphology (which includes a broadly rounded snout and no well-defined canthus rostralis). Related populations from eastern and central Queensland currently referred to D. platyurus include further deeply divergent lineages but additional material is required to resolve systematic boundaries in this region. PMID:27394511

  1. Adhesion mechanism of a gecko-inspired oblique structure with an adhesive tip for asymmetric detachment

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Yu; Takahashi, Kunio; Sato, Chiaki

    2015-12-01

    An adhesion model of an oblique structure with an adhesive tip is proposed by considering a limiting stress for adhesion to describe the detachment mechanism of gecko foot hairs. When a force is applied to the root of the oblique structure, normal and shear stresses are generated at contact and the adhesive tip is detached from the surface when reaching the limiting stress. An adhesion criterion that considers both the normal and shear stresses is introduced, and the asymmetric detachment of the oblique structure is theoretically investigated. In addition, oblique beam array structures are manufactured, and an inclination effect of the structure on the asymmetric detachment is experimentally verified.

  2. A new Bent-toed gecko (Squamata: Gekkonidae) from the Mekongga Mountains, South East Sulawesi, Indonesia.

    PubMed

    Riyanto, Awal; Kurniati, Hellen; Engilis, Andrew

    2016-01-01

    We describe Cyrtodactylus hitchi sp. nov., a new species of Bent-toed Gecko from montane forests in the Mekongga Mountains, South East Sulawesi, Indonesia. Although we cannot speculate about relationships, morphologically it shares several traits with C. batik, a large species known only from Mount Tompotika near the tip of Sulawesi's Eastern Peninsula. The following unique combination of characters distinguishes it from all other congeners: absence of precloacal groove, absence of precloacal and femoral pores, absence of enlarged femoral scales, no abrupt contact between large and small postfemoral scales, 18-20 lamellae under the fourth toes, and transversely enlarged, median subcaudal scales arranged in a single row. PMID:27394851

  3. Geckoprinting: assembly of microelectronic devices on unconventional surfaces by transfer printing with isolated gecko setal arrays.

    PubMed

    Jeong, Jaeyoung; Kim, Juho; Song, Kwangsun; Autumn, Kellar; Lee, Jongho

    2014-10-01

    Developing electronics in unconventional forms provides opportunities to expand the use of electronics in diverse applications including bio-integrated or implanted electronics. One of the key challenges lies in integrating semiconductor microdevices onto unconventional substrates without glue, high pressure or temperature that may cause damage to microdevices, substrates or interfaces. This paper describes a solution based on natural gecko setal arrays that switch adhesion mechanically on and off, enabling pick and place manipulation of thin microscale semiconductor materials onto diverse surfaces including plants and insects whose surfaces are usually rough and irregular. A demonstration of functional 'geckoprinted' microelectronic devices provides a proof of concept of our results in practical applications. PMID:25056216

  4. The cell-bound fructosyltransferase of Streptococcus salivarius: the carboxyl terminus specifies attachment in a Streptococcus gordonii model system.

    PubMed Central

    Rathsam, C; Giffard, P M; Jacques, N A

    1993-01-01

    The ftf gene, coding for the cell-bound beta-D-fructosyltransferase (FTF) of Streptococcus salivarius ATCC 25975, has been analyzed, and its deduced amino acid sequence has been compared with that of the secreted FTF of Streptococcus mutans and the levansucrases (SacBs) of Bacillus species. A unique proline-rich region detected at the C terminus of the FTF of S. salivarius preceded a hydrophobic terminal domain. This proline-rich region was shown to possess strong homology to the product of the prgC gene from pCF10 in Enterococcus faecalis, which encodes a pheromone-responsive protein of unknown function, as well as homology to the human proline-rich salivary protein PRP-4. A series of 3'-OH deletions of the S. salivarius ftf gene expressed in Streptococcus gordonii Challis LGR2 showed that the C terminus was required for cell surface attachment in this heterologous organism, as only the complete gene product was cell bound. This cell-bound activity was released in the presence of sucrose, suggesting that the mode of attachment and release of the S. salivarius FTF in S. gordonii was similar to that in its native host. PMID:8331080

  5. Attachment fixation of the overdenture: part II.

    PubMed

    Mensor, M C

    1978-01-01

    Many attachment systems of the bar or stud type increase the stability of an overdenture. When selecting an attachment it is essential to consider the skill of the dentist-laboratory team as well as the dexterity of the patient and to use the easiest system that will still improve stabilization. Generally simplicity in design, ease of maintenance, and minimum leverage should be paramount considerations in selection. Use of a guide such as the EM Gauge and of the EM Attachment Selector significantly reduces the confusion in selecting attachments and increases the working armamentarium for stabilizing an overdenture. PMID:340660

  6. Attachment Theory Applied to Juvenile Sex Offending.

    ERIC Educational Resources Information Center

    Goodrow, Kenneth K.; Lim, Mee-Gaik

    1998-01-01

    Attachment theory is applied to identify systemic patterns encouraging juveniles to commit sexual offenses. The role of the helping system in perpetuating offenses is reviewed. The priority of family integrity and the role of professionals in breaking cycles of abuse and repairing earlier destructive emotional attachments are discussed. (EMK)

  7. Developmental stages of the climbing gecko Tarentola annularis with special reference to the claws, pad lamellae, and subdigital setae.

    PubMed

    Khannoon, Eraqi R

    2015-07-01

    Studying the in ovo mode of development of squamates has the advantage of allowing easy access to embryos without surgically compromising gravid females. Despite the non-ophidian squamates being a very diverse lineage of reptiles, embryonic tables for individuals of this group are very few. Here, I present the first in ovo embryonic table for a basal multi-scansored, pad-bearing gecko, Tarentola annularis. In this gecko, only the III and IV digits bear claws. Eleven embryonic stages are described based on chronological development of morphological characteristics. In contrast to other previously studied geckos, this species exhibits a longer incubation period. Comparison with other squamates, embryonic development of T. annularis is an indicative of a conserved developmental strategy. Interestingly, the clawless digits of this gecko do exhibit claws during the first half of embryonic development. Thus, regression of claws in these digits could be an advantage of studying this particular taxon, as it raises the question, to be answered in future study, of which mechanisms could be responsible for such claw regression. Before hatching, the outer periderm layer sloughs revealing the functional setae. The present study provides not only a model for pentadactyl limbs and digit development, but also an example of a unique developmental phenomenon, as represented by claw regression. PMID:26055807

  8. Blade attachment assembly

    DOEpatents

    Garcia-Crespo, Andres Jose; Delvaux, John McConnell; Miller, Diane Patricia

    2016-05-03

    An assembly and method for affixing a turbomachine rotor blade to a rotor wheel are disclosed. In an embodiment, an adaptor member is provided disposed between the blade and the rotor wheel, the adaptor member including an adaptor attachment slot that is complementary to the blade attachment member, and an adaptor attachment member that is complementary to the rotor wheel attachment slot. A coverplate is provided, having a coverplate attachment member that is complementary to the rotor wheel attachment slot, and a hook for engaging the adaptor member. When assembled, the coverplate member matingly engages with the adaptor member, and retains the blade in the adaptor member, and the assembly in the rotor wheel.

  9. Dialectical Behaviour Therapy and attachment: vehicles for the development of resilience in young people leaving the care system.

    PubMed

    Andrew, Elizabeth; Williams, Jessica; Waters, Cerith

    2014-10-01

    It is well recognised that Looked After Children (LAC) and Young People Leaving Care (YPLC) have complex mental health needs and often engage in self-destructive behaviours such as self-harm, drug and alcohol use and suicide attempts. They can experience a high level of instability in relationships and frequently live transient lifestyles. Traditional mental health services for children, young people and adults have been unable to meet the attachment needs of this particular group such that they rarely benefit from therapeutic interventions and remain in a constant state of emotional dysregulation. This article describes the way in which two distinct therapeutic models - Dyadic Developmental Psychotherapy and Dialectical Behaviour Therapy - have been interwoven in order to engage and captivate young people leaving care in a therapeutic relationship. This relationship can then be used to help build skills to increase their resilience as they enter adulthood. PMID:24249838

  10. Comparative Studies of the Thick-Toed Geckos after the 16 and 12 Days Spaceflight in <> Experiments

    NASA Astrophysics Data System (ADS)

    Nikitin, V. B.; Proshchina, A. E.; Kharlamova, A. S.; Barabanov, V. M.; Krivova, J. S.; Godovalova, O. S.; Savelieva, E. S.; Makarov, A. N.; Gulimova, V. I.; Okshtein, I. L.; Naidenko, S. V.; Souza, K. A.; Almeida, E. A. C.; Ilyin, E. A.; Saveliev, S. V.

    2008-06-01

    In our study we compare the data from analysis of thick-toed geckoes Pachydactylus turneri from 16 and 12 days spaceflights onboard «Foton-M2» (M2) and «Foton-M3» (M3) satellites respectively. These studies were realized in the frames of Russian-American joint experiments. In M2 they were performed on 4 females and 1 male in each of the following groups: flight (F), basal (BC) and delayed synchronous (SC) controls. In M3 there were 5 females in each group. The animals were euthanized and examined using traditional histology, immunohistochemistry and X-ray microtomography. Mallory, Nissl and hematoxylin-eosin staining were used to compare the condition of brain, heart, liver, pancreas, spleen and small intestine. Brain and pancreas were also studied immunohistochemically. Behavior was registered by video camera in F and SC (M3). Thus we confirm the previous assumption that geckoes can preserve in weightlessness their ability to fi x themselves to the surfaces by their toe pads. We did not reveal in liver, pancreas, spleen and small intestine of F-M3 geckoes such evident changes like in F-M2 group. Glial destruction was detected immunohistochemically in the brains of F-M3 geckoes, especially in the cortical structures and epithalamus. Gluckocorticoids level for geckoes' feces in F-M2 was 4 times higher than in SC-M2 whereas the results for M3 were almost the same. Microtomografi c analysis of the femur bones showed some redistribution of the trabeculae in F-M3 group which occured in the direction from the outer compact bone to the bone center. Thus we conclude that in most structures of F-M3 animals the changes were less then in F-M2 ones. It can be explaned by shorter duration of M3 flight, higer temperature and the presence of water source. More prolonged experiments with larger groups of geckoes are necessary to verify the obtained data. Probably geckoes are well preadapted to conditions of spaceflight due to their specific biology.

  11. Scar-free cutaneous wound healing in the leopard gecko, Eublepharis macularius.

    PubMed

    Peacock, Hanna M; Gilbert, Emily A B; Vickaryous, Matthew K

    2015-11-01

    Cutaneous wounds heal with two possible outcomes: scarification or near-perfect integumentary restoration. Whereas scar formation has been intensively investigated, less is known about the tissue-level events characterising wounds that spontaneously heal scar-free, particularly in non-foetal amniotes. Here, a spatiotemporal investigation of scar-free cutaneous wound healing following full-thickness excisional biopsies to the tail and body of leopard geckos (Eublepharis macularius) is provided. All injuries healed without scarring. Cutaneous repair involves the development of a cell-rich aggregate within the wound bed, similar to scarring wounds. Unlike scar formation, scar-free healing involves a more rapid closure of the wound epithelium, and a delay in blood vessel development and collagen deposition within the wound bed. It was found that, while granulation tissue of scarring wounds is hypervascular, scar-free wound healing conspicuously does not involve a period of exuberant blood vessel formation. In addition, during scar-free wound healing the newly formed blood vessels are typically perivascular cell-supported. Immunohistochemistry revealed widespread expression of both the pro-angiogenic factor vascular endothelial growth factor A and the anti-angiogenic factor thrombospondin-1 within the healing wound. It was found that scar-free wound healing is an intrinsic property of leopard gecko integument, and involves a modulation of the cutaneous scar repair program. This proportional revascularisation is an important factor in scar-free wound healing. PMID:26360824

  12. Assessment of the GECKO-A modeling tool using chamber observations for C12 alkanes

    NASA Astrophysics Data System (ADS)

    Aumont, B.; La, S.; Ouzebidour, F.; Valorso, R.; Mouchel-Vallon, C.; Camredon, M.; Lee-Taylor, J. M.; Hodzic, A.; Madronich, S.; Yee, L. D.; Loza, C. L.; Craven, J. S.; Zhang, X.; Seinfeld, J.

    2013-12-01

    Secondary Organic Aerosol (SOA) production and ageing is the result of atmospheric oxidation processes leading to the progressive formation of organic species with higher oxidation state and lower volatility. Explicit chemical mechanisms reflect our understanding of these multigenerational oxidation steps. Major uncertainties remain concerning the processes leading to SOA formation and the development, assessment and improvement of such explicit schemes is therefore a key issue. The development of explicit mechanism to describe the oxidation of long chain hydrocarbons is however a challenge. Indeed, explicit oxidation schemes involve a large number of reactions and secondary organic species, far exceeding the size of chemical schemes that can be written manually. The chemical mechanism generator GECKO-A (Generator for Explicit Chemistry and Kinetics of Organics in the Atmosphere) is a computer program designed to overcome this difficulty. GECKO-A generates gas phase oxidation schemes according to a prescribed protocol assigning reaction pathways and kinetics data on the basis of experimental data and structure-activity relationships. In this study, we examine the ability of the generated schemes to explain SOA formation observed in the Caltech Environmental Chambers from various C12 alkane isomers and under high NOx and low NOx conditions. First results show that the model overestimates both the SOA yields and the O/C ratios. Various sensitivity tests are performed to explore processes that might be responsible for these disagreements.

  13. Removal mechanisms of dew via self-propulsion off the gecko skin

    PubMed Central

    Watson, Gregory S.; Schwarzkopf, Lin; Cribb, Bronwen W.; Myhra, Sverre; Gellender, Marty; Watson, Jolanta A.

    2015-01-01

    Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri. When condensation occurs, we show that small dew drops, as opposed to a thin film, form on the lizard's scales. As the droplets grow in size and merge, they can undergo self-propulsion off the skin and in the process can be carried away a sufficient distance to freely engage with external forces. We show that factors such as gravity, wind and fog provide mechanisms to remove these small droplets off the gecko skin surface. The formation of small droplets and subsequent removal from the skin may aid in reducing microbial contact (e.g. bacteria, fungi) and limit conducive growth conditions under humid environments. As well as providing an inhospitable microclimate for microorganisms, the formation and removal of small droplets may also potentially aid in other areas such as reduction and cleaning of some surface contaminants consisting of single or multiple aggregates of particles. PMID:25762647

  14. A new genus of miniaturized and pug-nosed gecko from South America (Sphaerodactylidae: Gekkota)

    PubMed Central

    Gamble, Tony; Daza, Juan D; Colli, Guarino R; Vitt, Laurie J; Bauer, Aaron M

    2011-01-01

    Sphaerodactyl geckos comprise five genera distributed across Central and South America and the Caribbean. We estimated phylogenetic relationships among sphaerodactyl genera using both separate and combined analyses of seven nuclear genes. Relationships among genera were incongruent at different loci and phylogenies were characterized by short, in some cases zero length, internal branches and poor phylogenetic support at most nodes. We recovered a polyphyletic Coleodactylus, with Coleodactylus amazonicus being deeply divergent from the remaining Coleodactylus species sampled. The C. amazonicus lineage possessed unique codon deletions in the genes PTPN12 and RBMX while the remaining Coleodactylus species had unique codon deletions in RAG1. Topology tests could not reject a monophyletic Coleodactylus, but we show that short internal branch lengths decreased the accuracy of topology tests because there were not enough data along short branches to support one phylogenetic hypothesis over another. Morphological data corroborated results of the molecular phylogeny, with Coleodactylus exhibiting substantial morphological heterogeneity. We identified a suite of unique craniofacial features that differentiate C. amazonicus not only from other Coleodactylus species, but also from all other geckos. We describe this novel sphaerodactyl lineage as a new genus, Chatogekko gen. nov. We present a detailed osteology of Chatogekko, characterizing osteological correlates of miniaturization that provide a framework for future studies in sphaerodactyl systematics and biology. PMID:22125341

  15. Ontogeny of Metabolic Rate and Red Blood Cell Size in Eyelid Geckos: Species Follow Different Paths

    PubMed Central

    Starostová, Zuzana; Konarzewski, Marek; Kozłowski, Jan; Kratochvíl, Lukáš

    2013-01-01

    While metabolism is a fundamental feature of all organisms, the causes of its scaling with body mass are not yet fully explained. Nevertheless, observations of negative correlations between red blood cell (RBC) size and the rate of metabolism suggest that size variation of these cells responsible for oxygen supply may play a crucial role in determining metabolic rate scaling in vertebrates. Based on a prediction derived from the Cell Metabolism Hypothesis, metabolic rate should increase linearly with body mass in species with RBC size invariance, and slower than linearly when RBC size increases with body mass. We found support for that prediction in five species of eyelid geckos (family Eublepharidae) with different patterns of RBC size variation during ontogenetic growth. During ontogeny, metabolic rate increases nearly linearly with body mass in those species of eyelid geckos where there is no correlation between RBC size and body mass, whereas non-linearity of metabolic rate scaling is evident in those species with ontogenetic increase of RBC size. Our findings provide evidence that ontogenetic variability in RBC size, possibly correlating with sizes of other cell types, could have important physiological consequences and can contribute to qualitatively different shape of the intraspecific relationship between metabolic rate and body mass. PMID:23705003

  16. Removal mechanisms of dew via self-propulsion off the gecko skin.

    PubMed

    Watson, Gregory S; Schwarzkopf, Lin; Cribb, Bronwen W; Myhra, Sverre; Gellender, Marty; Watson, Jolanta A

    2015-04-01

    Condensation resulting in the formation of water films or droplets is an unavoidable process on the cuticle or skin of many organisms. This process generally occurs under humid conditions when the temperature drops below the dew point. In this study, we have investigated dew conditions on the skin of the gecko Lucasium steindachneri. When condensation occurs, we show that small dew drops, as opposed to a thin film, form on the lizard's scales. As the droplets grow in size and merge, they can undergo self-propulsion off the skin and in the process can be carried away a sufficient distance to freely engage with external forces. We show that factors such as gravity, wind and fog provide mechanisms to remove these small droplets off the gecko skin surface. The formation of small droplets and subsequent removal from the skin may aid in reducing microbial contact (e.g. bacteria, fungi) and limit conducive growth conditions under humid environments. As well as providing an inhospitable microclimate for microorganisms, the formation and removal of small droplets may also potentially aid in other areas such as reduction and cleaning of some surface contaminants consisting of single or multiple aggregates of particles. PMID:25762647

  17. Modeling of the Gecko's skin microfibrillar structures using the Immersed Boundary method via DNS

    NASA Astrophysics Data System (ADS)

    Arenas, Isnardo; Carrasquillo, Kenneth; Leonardi, Stefano; Araya, Guillermo; Hussain, Fazle; Castillo, Luciano

    2013-11-01

    There is a current interest in surfaces that mimic the skin of some species (i.e., sharks, dolphins and geckos) in order to achieve drag reduction. The surface considered is based on the microfribrillar structures of a gecko's skin (Aksak et al. 2008). The structures are modeled by means of the immersed boundary method proposed by Fadlun et al. (2000). Direct simulations are performed to predict flow dynamics with a Reynolds number of 7000 based on the height of the channel and centerline velocity. The ratio of the height of the structure with respect to the height of the channel is approximately 0.05. The main motivation is to study how the microfribillar structures affect the momentum transfer from the viscous layer to the outer layer. The surface shows a reduction of the area affected by the shear stress due to the cavities formed by the pattern. As expected, the cavities create a low velocity zone thus decreasing the Reynolds shear stresses. Lambda-2 and Q-criterion were implemented to identify the elongated streamwise vortices. The results show that when compared to a flat channel the microfribillar structures tend to preserve these streamwise vortices instead of bursting into the outer layer which is a source of drag increase.

  18. Molecular phylogenetic and dating analyses using mitochondrial DNA sequences of eyelid geckos (Squamata: Eublepharidae).

    PubMed

    Jonniaux, Pierre; Kumazawa, Yoshinori

    2008-01-15

    Mitochondrial DNA sequences of approximately 2.3 kbp including the complete NADH dehydrogenase subunit 2 gene and its flanking genes, as well as parts of 12S and 16S rRNA genes were determined from major species of the eyelid gecko family Eublepharidae sensu [Kluge, A.G. 1987. Cladistic relationships in the Gekkonoidea (Squamata, Sauria). Misc. Publ. Mus. Zool. Univ. Michigan 173, 1-54.]. In contrast to previous morphological studies, phylogenetic analyses based on these sequences supported that Eublepharidae and Gekkonidae form a sister group with Pygopodidae, raising the possibility of homoplasious character change in some key features of geckos, such as reduction of movable eyelids and innovation of climbing toe pads. The phylogenetic analyses also provided a well-resolved tree for relationships between the eublepharid species. The Bayesian estimation of divergence times without assuming the molecular clock suggested the Jurassic divergence of Eublepharidae from Gekkonidae and radiations of most eublepharid genera around the Cretaceous. These dating results appeared to be robust against some conditional changes for time estimation, such as gene regions used, taxon representation, and data partitioning. Taken together with geological evidence, these results support the vicariant divergence of Eublepharidae and Gekkonidae by the breakup of Pangea into Laurasia and Gondwanaland, and recent dispersal of two African eublepharid genera from Eurasia to Africa after these landmasses were connected in the Early Miocene. PMID:18029117

  19. Fine-Scale Genetic Structure Arises during Range Expansion of an Invasive Gecko

    PubMed Central

    Short, Kristen Harfmann; Petren, Kenneth

    2011-01-01

    Processes of range expansion are increasingly important in light of current concerns about invasive species and range shifts due to climate change. Theoretical studies suggest that genetic structuring may occur during range expansion. Ephemeral genetic structure can have important evolutionary implications, such as propagating genetic changes along the wave front of expansion, yet few studies have shown evidence of such structure. We tested the hypothesis that genetic structure arises during range expansion in Hemidactylus mabouia, a nocturnal African gecko recently introduced to Florida, USA. Twelve highly variable microsatellite loci were used to screen 418 individuals collected from 43 locations from four sampling sites across Florida, representing a gradient from earlier (∼1990s) to very recent colonization. We found earlier colonized locations had little detectable genetic structure and higher allelic richness than more recently colonized locations. Genetic structuring was pronounced among locations at spatial scales of tens to hundreds of meters near the leading edge of range expansion. Despite the rapid pace of range expansion in this introduced gecko, dispersal is limited among many suitable habitat patches. Fine-scale genetic structure is likely the result of founder effects during colonization of suitable habitat patches. It may be obscured over time and by scale-dependent modes of dispersal. Further studies are needed to determine if such genetic structure affects adaptation and trait evolution in range expansions and range shifts. PMID:22053186

  20. A gecko skin micro/nano structure - A low adhesion, superhydrophobic, anti-wetting, self-cleaning, biocompatible, antibacterial surface.

    PubMed

    Watson, Gregory S; Green, David W; Schwarzkopf, Lin; Li, Xin; Cribb, Bronwen W; Myhra, Sverre; Watson, Jolanta A

    2015-07-01

    Geckos, and specifically their feet, have attracted significant attention in recent times with the focus centred around their remarkable adhesional properties. Little attention however has been dedicated to the other remaining regions of the lizard body. In this paper we present preliminary investigations into a number of notable interfacial properties of the gecko skin focusing on solid and aqueous interactions. We show that the skin of the box-patterned gecko (Lucasium sp.) consists of dome shaped scales arranged in a hexagonal patterning. The scales comprise of spinules (hairs), from several hundred nanometres to several microns in length, with a sub-micron spacing and a small radius of curvature typically from 10 to 20 nm. This micro and nano structure of the skin exhibited ultralow adhesion with contaminating particles. The topography also provides a superhydrophobic, anti-wetting barrier which can self clean by the action of low velocity rolling or impacting droplets of various size ranges from microns to several millimetres. Water droplets which are sufficiently small (10-100 μm) can easily access valleys between the scales for efficient self-cleaning and due to their dimensions can self-propel off the surface enhancing their mobility and cleaning effect. In addition, we demonstrate that the gecko skin has an antibacterial action where Gram-negative bacteria (Porphyromonas gingivalis) are killed when exposed to the surface however eukaryotic cell compatibility (with human stem cells) is demonstrated. The multifunctional features of the gecko skin provide a potential natural template for man-made applications where specific control of liquid, solid and biological contacts is required. PMID:25772496

  1. Infant Feeding and Attachment.

    ERIC Educational Resources Information Center

    Ainsworth, Mary D. Salter; Tracy, Russel L.

    This paper has two major purposes: first, to consider how infant feeding behavior may fit into attachment theory; and second, to cite some evidence to show how an infant's early interaction with his mother in the feeding situation is related to subsequent development. It was found that sucking and rooting are precursor attachment behaviors that…

  2. Attachment Theory and Mindfulness

    ERIC Educational Resources Information Center

    Snyder, Rose; Shapiro, Shauna; Treleaven, David

    2012-01-01

    We initiate a dialog between two central areas in the field of psychology today: attachment theory/research and mindfulness studies. The impact of the early mother-infant relationship on child development has been well established in the literature, with attachment theorists having focused on the correlation between a mother's capacity for…

  3. Attachment and Early Maltreatment.

    ERIC Educational Resources Information Center

    Egeland, Byron; Sroufe, L. Alan

    1981-01-01

    Attachment outcomes of 31 maltreatment cases (involving extreme neglect or abuse), selected from a total poverty sample of 267 high-risk mothers and their children, were compared to those of a subsample of 33 cases with a history of excellent care. Attachment was assessed when infants were 12 and 18 months old. (Author/MP)

  4. Separation and Attachment

    ERIC Educational Resources Information Center

    Honig, Alice Sterling

    2005-01-01

    Developing secure attachments with babies gives them a very special gift--the foundation for good infant mental health! In this article, the author discusses how to develop secure attachments with babies. Babies who are in the care of others during the day often suffer from separations from their special adults. Thirteen "tips" to ensure that…

  5. Oxytocin enhances the experience of attachment security

    PubMed Central

    Buchheim, Anna; Heinrichs, Markus; George, Carol; Pokorny, Dan; Koops, Eva; Henningsen, Peter; O’Connor, Mary-Frances; Gundel, Harald

    2011-01-01

    Summary Repeated interactions between infant and caregiver result in either secure or insecure relationship attachment patterns, and insecure attachment may affect individual emotion-regulation and health. Given that oxytocin enhances social approach behavior in animals and humans, we hypothesized that oxytocin might also promote the experience of attachment security in humans. Within a 3-week interval 26 healthy male students classified with an insecure attachment pattern were invited twice to an experimental session. Within each session, a single dose of oxytocin or placebo was administered, using a double-blind, placebo-controlled within-subject design. In both conditions, subjects completed an attachment task based on the Adult Attachment Projective Picture System (AAP). Thirty-two AAP picture system presentations depicted attachment-related events (e.g. illness, solitude, separation, loss), and were each accompanied by four prototypical phrases representing one secure and three insecure attachment categories. In the oxytocin condition, a significant proportion of these insecure subjects (N = 18; 69%) changed their rankings of “secure attachment” phrases towards the more appropriate for the AAP picture presentation, and the same subjects decreased in overall rating of the “insecure attachment” phrases. In particular, there was a significant decrease in the number of subjects ranking the pictures with “insecure-preoccupied” phrases from the placebo to the oxytocin condition. We find that a single dose of intranasally administered oxytocin is sufficient to induce a significant increase in the experience of attachment security in adults classified previously as insecure. PMID:19457618

  6. Structural-acoustic model of a rectangular plate-cavity system with an attached distributed mass and internal sound source: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Pirnat, Miha; Čepon, Gregor; Boltežar, Miha

    2014-03-01

    In this paper three approaches are combined to develop a structural-acoustic model of a rectangular plate-cavity system with an attached distributed mass and internal sound source. The first approach results from a recently presented analysis based on the Rayleigh-Ritz method and is used to circumvent the difficulties in obtaining the natural frequencies and mode shapes of a plate with an attached, distributed mass. Furthermore, different plate boundary conditions can be accommodated. The resulting mode shapes are defined as continuous functions; this is advantageous as they can be directly used in the second approach, i.e., the classic modal-interaction approach in order to obtain the coupled equations of the system. Finally, in the third approach a group of point sources emitting a pressure pulse in the time domain is used to model an internal sound source. For the validation of the developed model an experiment was conducted in two configurations using a simply supported aluminium plate and a clamped plate coupled with a plexiglas box containing a loudspeaker. Good agreement was found between the analytical and experimental data.

  7. Electromagnetic attachment mechanism

    NASA Technical Reports Server (NTRS)

    Monford, Leo G., Jr. (Inventor)

    1992-01-01

    An electromagnetic attachment mechanism is disclosed for use as an end effector of a remote manipulator system. A pair of electromagnets, each with a U-shaped magnetic core with a pull-in coil and two holding coils, are mounted by a spring suspension system on a base plate of the mechanism housing with end pole pieces adapted to move through openings in the base plate when the attractive force of the electromagnets is exerted on a strike plate of a grapple fixture affixed to a target object. The pole pieces are spaced by an air gap from the strike plate when the mechanism first contacts the grapple fixture. An individual control circuit and power source is provided for the pull-in coil and one holding coil of each electromagnet. A back-up control circuit connected to the two power sources and a third power source is provided for the remaining holding coils. When energized, the pull-in coils overcome the suspension system and air gap and are automatically de-energized when the pole pieces move to grapple and impose a preload force across the grapple interface. A battery backup is a redundant power source for each electromagnet in each individual control circuit and is automatically connected upon failure of the primary source. A centerline mounted camera and video monitor are used in cooperation with a target pattern on the reflective surface of the strike plate to effect targeting and alignment.

  8. Durability Evaluation of a Thin Film Sensor System With Enhanced Lead Wire Attachments on SiC/SiC Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Kiser, J. Douglas; Singh, Mrityunjay; Cuy, Mike; Blaha, Charles A.; Androjna, Drago

    2000-01-01

    An advanced thin film sensor system instrumented on silicon carbide (SiC) fiber reinforced SiC matrix ceramic matrix composites (SiC/SiC CMCs), was evaluated in a Mach 0.3 burner rig in order to determine its durability to monitor material/component surface temperature in harsh environments. The sensor system included thermocouples in a thin film form (5 microns thick), fine lead wires (75 microns diameter), and the bonds between these wires and the thin films. Other critical components of the overall system were the heavy, swaged lead wire cable (500 microns diameter) that contained the fine lead wires and was connected to the temperature readout, and ceramic attachments which were bonded onto the CMCs for the purpose of securing the lead wire cables, The newly developed ceramic attachment features a combination of hoops made of monolithic SiC or SiC/SiC CMC (which are joined to the test article) and high temperature ceramic cement. Two instrumented CMC panels were tested in a burner rig for a total of 40 cycles to 1150 C (2100 F). A cycle consisted of rapid heating to 1150 C (2100 F), a 5 minute hold at 1150 C (2100 F), and then cooling down to room temperature in 2 minutes. The thin film sensor systems provided repeatable temperature measurements for a maximum of 25 thermal cycles. Two of the monolithic SiC hoops debonded during the sensor fabrication process and two of the SiC/SiC CMC hoops failed during testing. The hoops filled with ceramic cement, however, showed no sign of detachment after 40 thermal cycle test. The primary failure mechanism of this sensor system was the loss of the fine lead wire-to-thin film connection, which either due to detachment of the fine lead wires from the thin film thermocouples or breakage of the fine wire.

  9. In Vivo Measurement of Mesokinesis in Gekko gecko: The Role of Cranial Kinesis during Gape Display, Feeding and Biting

    PubMed Central

    Montuelle, Stéphane J.; Williams, Susan H.

    2015-01-01

    Cranial kinesis refers to movements of skeletal sub-units relative to one another at mobile sutures within the skull. The presence and functional significance of cranial kinesis has been investigated in various vertebrates, with much of our understanding coming from comparative studies and manipulation of ligamentous specimens. Drawing on these studies, cranial kinesis in lizards has been modeled as a four-bar linkage system involving streptostyly (rotation of the quadrate), hypokinesis (dorsoventral flexion and extension of the palato-maxillary sub-unit), mesokinesis (dorsoventral flexion and extension of the snout at the fronto-parietal suture) and metakinesis (sliding movements between parietal and supraocciptal bones). In vivo studies, although limited, suggest that cranial kinesis serves an important role during routine behaviors such as feeding. Here, we use X-ray Reconstruction Of Moving Morphology to further quantify mesokinesis in vivo in Gekko gecko during three routine behaviors: gape display, biting and post-ingestion feeding. During gape display, the snout rotates dorsally above rest position, with mesokinesis accounting for a 10% increase in maximum gape over that achieved solely by the depression of the lower jaw. During defensive biting, the snout rotates ventrally below rest position to participate in gape closure. Finally, ventroflexion of the snout also occurs during post-ingestion feeding, accounting for 42% of gape closure during intra-oral transport, 86% during puncture-crushing, and 61% during pharyngeal packing. Mesokinesis thus appears to facilitate prey puncturing by allowing the snout to rotate ventrally so that the upper teeth pierce the prey item, thus limiting the need for large movements of the lower jaw. This is suggested to maintain a firm grip on the prey and reduce the possibility of prey escape. More generally, this study demonstrates that mesokinesis is a key component of defensive biting and gape display behaviors, as well as

  10. Modelling of biological Cr(VI) removal in draw-fill reactors using microorganisms in suspended and attached growth systems.

    PubMed

    Tekerlekopoulou, Athanasia G; Tsiflikiotou, Maria; Akritidou, Lydia; Viennas, Anastasios; Tsiamis, George; Pavlou, Stavros; Bourtzis, Kostas; Vayenas, Dimitris V

    2013-02-01

    The kinetics of hexavalent chromium bio-reduction in draw-fill suspended and attached growth reactors was examined using sugar as substrate and indigenous microorganisms from the industrial sludge of the Hellenic Aerospace Industry. Initially, experiments in suspended growth batch reactors for Cr (VI) concentrations of 1.4-110 mg/l were carried out, to extensively study the behaviour of a mixed culture. The maximum Cr(VI) reduction rate of 2 mg/l h was achieved for initial concentration 12.85 mg/l with biomass production rate 4.1 mg biomass/l h. Analysis of the microbial structure in the batch reactor culture indicated that the dominant bacterial communities were constituted by bacterial members of Raoultella sp., Citrobacter sp., Klebsiella sp., Salmonella sp., Achromobacter sp. and Kerstersia sp. while the dominant fungal strain was that of Pichia jadinii. Experiments using the same mixed culture were also carried out in packed-bed reactors with plastic support media. High removal rates were achieved (2.0 mg/l h) even in high initial concentrations (109 mg/l). A combination of the model of Tsao and Hanson for growth enhancement and that of Aiba and Shoda for growth inhibition was used in order to describe and predict the process of Cr(VI) bio-reduction in suspended growth and packed-bed reactors. Kinetic constants of the equation obtained from both batch (or draw-fill) culture experiments. In the draw-fill experiments at the packed-bed reactor, hexavalent chromium inhibitory effects were minimized increasing the inhibitory constant value K(i)' at 148.5 mg/l, compared to suspended growth experiments which was K(i) = 8.219 mg/l. The model adequately predicts hexavalent chromium reduction in both batch reactors for all initial concentrations tested. PMID:23182668

  11. The star identification, pointing and tracking system of UVSTAR, an attached payload instrument system for the Shuttle Hitchhiker-M platform

    NASA Technical Reports Server (NTRS)

    Decarlo, Francesco; Stalio, Roberto; Trampus, Paolo; Broadfoot, A. Lyle; Sandel, Bill R.; Sicuranza, Giovanni

    1993-01-01

    We describe an algorithm for star identification and pointing/tracking of a spaceborne electro-optical system and simulation analyses to test the algorithm. The algorithm will be implemented in the guiding system of UVSTAR, a spectrographic telescope for observations of astronomical and planetary sources operating in the 500-1250 A waveband at approximately 1 A resolution. The experiment is an attached payload and will fly as a Hitchhiker-M payload on the Shuttle. UVSTAR includes capabilities for independent target acquisition and tracking. The spectrograph package has internal gimbals that allow angular movement of plus or minus 3 deg from the central position. Rotation about the azimuth axis (parallel to the Shuttle z axis) and elevation axis (parallel to the Shuttle x axis) will actively position the field of view to center the target of interest in the fields of the spectrographs. The algorithm is based on an on-board catalog of stars. To identify star fields, the algorithm compares the positions of stars recorded by the guiding imager to positions computed from the on-board catalog. When the field has been identified, its position within the guiding imager field of view can be used to compute the pointing corrections necessary to point to a target of interest. In tracking mode, the software uses the past history to predict the quasi-periodic attitude control motions of the shuttle and sends pointing commands to cancel the motion and stabilize UVSTAR on the target. The guiding imager (guider) will have an 80-mm focal length and f/1.4 optics giving a field of view of 6 deg x 4.5 deg using a 385 x 288 pixel intensified CCD. It will be capable of providing high accuracy (better than 2 arc-sec) attitude determination from coarse (6 deg x 4.5 deg) initial knowledge of the pointing direction; and of pointing toward the target. It will also be capable of tracking at the same high accuracy with a processing time of less than a few hundredths of a second.

  12. SPENT FUEL CASK IMPACT LIMITER ATTACHMENT DESIGN DEFICIENCIES

    SciTech Connect

    Leduc, D; Jeffery England, J

    2007-10-16

    A recent structural analysis of the T-3 Spent Fuel Containment Cask found problems with the design of the attachment system. Assumptions in the original SARP concerning the loading in the attachment bolts were found to be inaccurate in certain drop orientations. Similar weaknesses in the attachment system designs of other casks were also noted. This paper documents the lessons learned and their applicability to impact limiter attachment system designs.

  13. Synthesis and characterization of multiwalled carbon nanotube/IPMC actuator for imitating locomotion of gecko's toes

    NASA Astrophysics Data System (ADS)

    He, Qingsong; Yu, Min; Ding, Yan; Dai, Zhendong

    2012-04-01

    A multi-walled carbon nanotube (MCNT)/Nafion nanocomposite was fabricated by dispersion of treated MCNTs in a Nafion solution. The multi-walled carbon nanotube (MCNT) filler was prepared with the cationic surfactant cetyl trimethyl ammonium bromide. Starting from cast Nafion membranes, IPMCs were manufactured by electroless plating. The current and the blocking force were measured with an IPMC actuation testing apparatus. Compared with a bare Nafion-based IPMC, the blocking force of the new IPMC improved 1-1.4 times, and the current increased by 33%-67%. The clearly enhanced performance of the new MCNT filler-based IPMC is attributed to the well-distributed MCNTs that improved the electrical properties of the IPMC. Finally, the new IPMC was successfully employed to directly actuate gecko-inspired adhesive arrays that we fabricated by ourselves.

  14. Investigating SOA from alpha-pinene ozonolysis with the GECKO modeling tool.

    NASA Astrophysics Data System (ADS)

    Lee-Taylor, J. M.; Madronich, S.; Aumont, B.; Lawler, M. J.; Smith, J. N.; Camredon, M.

    2014-12-01

    Atmospheric oxidation of terpenes leads to a rich variety of functionalized organic molecules of vapor pressures low enough to permit their condensation on particles. GECKO-A is an explicit chemical model useful for investigating fine details of tropospheric oxidation chemistry. The TDCIMS measurement technique allows the identification of specific molecular formulae in aerosol particles. We have incorporated recent advances in alpha-pinene chemistry into the model and apply it to study alpha-pinene ozonolysis and its subsequent condensable products. We assess the degree to which particle size affects modeled aerosol chemical composition and structure from alpha-pinene ozonolysis and compare the statistical composition of the modeled aerosol to that observed by TDCIMS in chamber studies.

  15. A new Bent-toed Gecko (Squamata: Gekkonidae: Cyrtodactylus) from Phetchaburi Province, Thailand.

    PubMed

    Pauwels, Olivier S G; Sumontha, Montri; Bauer, Aaron M

    2016-01-01

    A new Bent-toed Gecko, Cyrtodactylus phetchaburiensis sp. nov. is described from the Tha Yang District of Phetchaburi Province, western Thailand. It is a medium-sized Cyrtodactylus (SVL to at least 63.2 mm), with small, mostly keeled tubercles in 20 regular longitudinal rows on dorsum; 33 scales across mid-venter between lowest rows of flank tubercles; enlarged row of femoral scales present; five precloacal pores in male, femoral pores and precloacal groove absent; 5-6 broad basal lamellae and 11 narrow distal lamellae beneath digit IV of pes; and a single median row of transversely enlarged subcaudal scales present. It has a dorsal colour pattern of large, dark, diffusely-edged markings on a fawn background and a pair of dark scapular patches. The species is a member of the Central Indochinese (Thai-Myanmar) clade of Cyrtodactylus and is most closely related to C. oldhami (Theobald), from which it differs in colour pattern. PMID:27394348

  16. Geckoprinting: assembly of microelectronic devices on unconventional surfaces by transfer printing with isolated gecko setal arrays

    PubMed Central

    Jeong, Jaeyoung; Kim, Juho; Song, Kwangsun; Autumn, Kellar; Lee, Jongho

    2014-01-01

    Developing electronics in unconventional forms provides opportunities to expand the use of electronics in diverse applications including bio-integrated or implanted electronics. One of the key challenges lies in integrating semiconductor microdevices onto unconventional substrates without glue, high pressure or temperature that may cause damage to microdevices, substrates or interfaces. This paper describes a solution based on natural gecko setal arrays that switch adhesion mechanically on and off, enabling pick and place manipulation of thin microscale semiconductor materials onto diverse surfaces including plants and insects whose surfaces are usually rough and irregular. A demonstration of functional ‘geckoprinted’ microelectronic devices provides a proof of concept of our results in practical applications. PMID:25056216

  17. The fourth Bent-toed Gecko of the genus Cyrtodactylus (Squamata: Gekkonidae) from Java, Indonesia.

    PubMed

    Riyanto, Awal; Grismer, L Lee; Wood, Perry L

    2015-01-01

    Cyrtodactylus petani sp. nov. is a new species of Bent-toed Gecko from Java, Indonesia that had been masquerading under the name C. fumosus (Müller, 1895). The new species is differentiated from C. fumosus and all its Sundaland congeners by having the following combination of morphological characters: a maximum SVL of 57.2 mm; nine or ten supralabials; seven or eight infralabials; strongly tuberculate body and limbs; 20-25 paravertebral tubercles; 30-35 ventral scales; enlarged precloacal scales; enlarged femoral scales; 17-18 subdigital lamellae on the fourth toe; 31-35 continuous precloacal and femoral pores in males, pores absent in females; no precloacal groove; no enlarged median subcaudals; tubercles on anterior portion of tail; no reticulated pattern on top of head; a blotched dorsal pattern; and no paired, dark, semi-lunar shaped blotches on the nape. PMID:26701567

  18. Effect of 12-Day Spaceflight on Brain of Thick-Toed Geckos

    NASA Astrophysics Data System (ADS)

    Proshchina, A. E.; Karlamova, A. S.; Barabanovet, V. M.; Godovalova, O. S.; Guilimova, V. I.; Krivova, Y. S.; Makarov, A. N.; Nikitin, V. B.; Savelieva, E. S.; Saveliev, S. V.

    2008-06-01

    In the frames of Russian-American joint space experiment onboard Foton-M3 satellite there was undertaken a study of spaceflight influence on brain of the thick-toed gecko (Pachydactylus turneri Gray, 1864). Serial brain sections were stained according to Nissl and also the immunohistochemical method with antibodies to NGF-receptor (p75NGFR), CD95 (also known as Fas and APO-1), glial fibrillary acidic protein (GFAP) and transferrin-receptor (CD71). Detailed examination of the sections of rhombencephalon revealed cytological changes in the neuron bodies of vestibular nuclei inside the flight group. Immunohistochemicaly we found the increase density of CD95 and p75NGFR and decrease of GFAP expression in medial cortex and epithalamus in flight group compared both control.

  19. Visual pigments and spectral sensitivity of the diurnal gecko Gonatodes albogularis.

    PubMed

    Ellingson, J M; Fleishman, L J; Loew, E R

    1995-11-01

    The visual pigments and oil droplets in the retina of the diurnal gecko Gonatodes albogularis were examined microspectrophotometrically, and the spectral sensitivity under various adapting conditions was recorded using electrophysiological responses. Three classes of visual pigments were identified, with lambda max at about 542, 475, and 362 nm. Spectral sensitivity functions revealed a broad range of sensitivity, with a peak at approximately 530-540 nm. The cornea and oil droplets were found to be transparent across a range from 350-700 nm, but the lens absorbed short wavelength light below 450 nm. Despite the filtering effect of the lens, a secondary peak in spectral sensitivity to ultraviolet wavelengths was found. These results suggest that G. albogularis does possess the visual mechanisms for discrimination of the color pattern of conspecifics based on either hue or brightness. These findings are discussed in terms of the variation in coloration and social behavior of Gonatodes. PMID:7473305

  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. PMID:25244526

  1. Gecko gaskets for self-sealing and high-strength reversible bonding of microfluidics.

    PubMed

    Wasay, A; Sameoto, D

    2015-07-01

    We report in this work a novel reversible bonding technique for elastomeric microfluidic devices by integrating gecko-inspired dry adhesives with microfluidic channels which greatly enhances the bonding strength of reversibly sealed channels. The concept is applicable to nearly any elastomer and can be used to bond against any smooth surface which allows for van der Waals interactions. It does not require any solvents or glues or sources for plasma activation or thermal-compressive loading to aid the bonding process and is achievable at zero extra cost. We also demonstrate a quick fabrication technique involving soft master thermo-compressive molding of these microfluidic devices with thermoplastic elastomers. The resultant devices can be used for both pressure driven and non-pressure driven flows. We report the maximum contained pressure of these devices manufactured from two grades of styrene ethylene butylene styrene (SEBS) by conducting a burst pressure test with various substrates. PMID:26016928

  2. Direct integration of MEMS, dielectric pumping and cell manipulation with reversibly bonded gecko adhesive microfluidics

    NASA Astrophysics Data System (ADS)

    Warnat, S.; King, H.; Wasay, A.; Sameoto, D.; Hubbard, T.

    2016-09-01

    We present an approach to form a microfluidic environment on top of MEMS dies using reversibly bonded microfluidics. The reversible polymeric microfluidics moulds bond to the MEMS die using a gecko-inspired gasket architecture. In this study the formed microchannels are demonstrated in conjunction with a MEMS mechanical single cell testing environment for BioMEMS applications. A reversible microfluidics placement technique with an x-y and rotational accuracy of  ±2 µm and 1° respectively on a MEMS die was developed. No leaks were observed during pneumatic pumping of common cell media (PBS, sorbitol, water, seawater) through the fluidic channels. Thermal chevron actuators were successful operated inside this fluidic environment and a performance deviation of ~15% was measured compared to an open MEMS configuration. Latex micro-spheres were pumped using traveling wave di-electrophoresis and compared to an open (no-microfluidics) configuration with velocities of 24 µm s‑1 and 20 µm s‑1.

  3. The phylogenetic distribution, anatomy and histology of the post-cloacal bones and adnexa of geckos.

    PubMed

    Russell, Anthony P; Vickaryous, Matthew K; Bauer, Aaron M

    2016-02-01

    Post-cloacal bones of gekkotans may be present as a single (medial) pair, two pairs (medial and lateral), or may be lacking. We, herein, demonstrate that the presence of a single medial pair is the ancestral condition for the Gekkota, that the lateral pair is of sporadic occurrence within and between families, except for the Eublepharidae where it is universal, and that absence is also of sporadic occurrence except for the Sphaerodactylidae where it is the ancestral condition. Adult male Tokay geckos (Gekko gecko) possess only the medial pair of bones, and these exhibit a regionally-specific expression of woven, fibrolamellar, and lamellar bone, and an enclosed medullary cavity. Females and small juvenile males lack bony elements but exhibit a conspicuous band of dense connective tissue located about the anterior and lateral margins of the cloacal sacs. As males grow and attain sexual maturity, the medial post-cloacal bones condense in this band of dense connective tissue, and are thus shown to be dermal ossifications, similar to osteoderms but with muscular associations (although this is also known for crocodylians). Based upon ontogenetic data we set forth a scenario to explain the loss of the medial post-cloacal bones in various lineages. Differential staining of the cloacal sacs failed to reveal any specialized glandular structures. Investigation of the post-cloacal spurs shows them to be associated with cellular connective tissue of a type similar to that found in the vicinity of the medial post-cloacal bones. This suggests that the lateral post-cloacal bones may also be dermal bones, but histological evidence is needed to corroborate this. PMID:26606399

  4. Adhesion switch on a gecko-foot inspired smart nanocupule surface

    NASA Astrophysics Data System (ADS)

    Song, Wenlong

    2014-10-01

    A gecko-foot inspired nanocupule surface prepared by an AAO template covering method was composed of poly(N-isopropylacrylamide) and polystyrene blend. Both superhydrophobicity and high adhesion force were exhibited on the PNIPAm/PS film at room temperature. Moreover, by controlling the temperature, the wettability of the film could be switched between 138.1 +/- 5.5° and 150.6 +/- 1.5°, and the adhesion force could also be correspondingly tuned accurately by temperature. This reversibility in both wettability and adhesion force could be used to construct smart devices for fine selection of water droplets. The proof-of-concept was demonstrated by the selective catching of precise weight controlled water droplets at different temperatures. This work could help us to design new type of devices for blood bioanalysis or lossless drug transportation.A gecko-foot inspired nanocupule surface prepared by an AAO template covering method was composed of poly(N-isopropylacrylamide) and polystyrene blend. Both superhydrophobicity and high adhesion force were exhibited on the PNIPAm/PS film at room temperature. Moreover, by controlling the temperature, the wettability of the film could be switched between 138.1 +/- 5.5° and 150.6 +/- 1.5°, and the adhesion force could also be correspondingly tuned accurately by temperature. This reversibility in both wettability and adhesion force could be used to construct smart devices for fine selection of water droplets. The proof-of-concept was demonstrated by the selective catching of precise weight controlled water droplets at different temperatures. This work could help us to design new type of devices for blood bioanalysis or lossless drug transportation. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04090b

  5. Chloride effect on the early photolysis intermediates of a gecko cone-type visual pigment.

    PubMed

    Lewis, J W; Liang, J; Ebrey, T G; Sheves, M; Kliger, D S

    1995-05-01

    Nanosecond laser photolysis measurements were conducted on the cone-type visual pigment P521 in digitonin extracts of Tokay gecko (Gekko gekko) retina containing physiological chloride ion levels and also on samples which had been chloride depleted or which contained high levels (4 M) of chloride. Absorbance difference spectra were recorded at a sequence of time delays from 30 ns to 60 microseconds following excitation with a pulse of either 532- or 477-nm actinic light. Global analysis showed the kinetic decay data for gecko pigment P521 to be best fit by two exponential processes under all chloride conditions. The initial photoproduct detected had a broad spectrum characteristic of an equilibrated mixture of a Batho P521 intermediate with its blue-shifted intermediate (BSI P521) decay product. The first exponential process was assigned to the decay of this mixture to the Lumi P521 intermediate. The second exponential process was identified as the decay of Lumi P521 to Meta I P521. The initial photoproduct's spectrum exhibited a strong dependence on chloride concentration, indicating that chloride affects the composition of the equilibrated mixture of Batho P521 and BSI P521. These results suggest that the affinity for chloride is reduced approximately 5-fold in the Batho P521 intermediate and approximately 50-fold in the BSI P521 intermediate. Chloride concentration also affects the apparent decay rate of the equilibrated mixture. When the apparent decay rate is corrected for the composition of the equilibrated mixture, a relatively invariant microscopic rate constant is obtained for BSI decay (k = 1/55 ns-1).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7727442

  6. Importance of loading and unloading procedures for gecko-inspired controllable adhesives.

    PubMed

    Tamelier, John; Chary, Sathya; Turner, Kimberly L

    2013-08-27

    The importance of loading and unloading procedures has been shown in a variety of different methods for biological dry adhesives, such as the fibers on the feet of the Tokay gecko, but biomimetic dry adhesives have yet to be explored in a similar manner. To date, little work has systematically varied multiple parameters to discern the influence of the testing procedure, and the effect of the approach angle remains uncertain. In this study, a synthetic adhesive is moved in 13 individual approach and retraction angles relative to a flat substrate as well as 9 different shear lengths to discern how loading and unloading procedures influence the preload, adhesion, and shear/friction forces supported. The synthetic adhesive, composed of vertical 10 μm diameter semicircular poly(dimethylsiloxane) fibers, is tested against a 4 mm diameter flat glass puck on a home-built microtribometer using both vertical approach and retraction tests and angled approach and retraction tests. The results show that near maximum adhesion and friction can be obtained for most approach and retraction angles, provided that a sufficient shear length is performed. The results also show that the reaction forces during adhesive placement can be significantly reduced by using specific approach angles, resulting for the vertical fibers in a 38-fold increase in the ratio of adhesion force to preload force, μ', when compared to that when using a vertical approach. These results can be of use to those currently researching gecko-inspired adhesives when designing their testing procedures and control algorithms for climbing and perching robots. PMID:23875720

  7. Contaminant adhesion (aerial/ground biofouling) on the skin of a gecko

    PubMed Central

    Watson, Gregory S.; Cribb, Bronwen W.; Schwarzkopf, Lin; Watson, Jolanta A.

    2015-01-01

    In this study, we have investigated the micro- and nano-structuring and contaminant adhesional forces of the outer skin layer of the ground dwelling gecko—Lucasium steindachneri. The lizard's skin displayed a high density of hairs with lengths up to 4 μm which were spherically capped with a radius of curvature typically less than 30 nm. The adhesion of artificial hydrophilic (silica) and hydrophobic (C18) spherical particles and natural pollen grains were measured by atomic force microscopy and demonstrated extremely low values comparable to those recorded on superhydrophobic insects. The lizard scales which exhibited a three-tier hierarchical architecture demonstrated higher adhesion than the trough regions between scales. The two-tier roughness of the troughs comprising folding of the skin (wrinkling) limits the number of contacting hairs with particles of the dimensions used in our study. The gecko skin architecture on both the dorsal and trough regions demonstrates an optimized topography for minimizing solid–solid and solid–liquid particle contact area, as well as facilitating a variety of particulate removal mechanisms including water-assisted processes. These contrasting skin topographies may also be optimized for other functions such as increased structural integrity, levels of wear protection and flexibility of skin for movement and growth. While single hair adhesion is low, contributions of many thousands of individual hairs (especially on the abdominal scale surface and if deformation occurs) may potentially aid in providing additional adhesional capabilities (sticking ability) for some gecko species when interacting with environmental substrates such as rocks, foliage and even man-made structuring. PMID:26063826

  8. Origin and in situ diversification in Hemidactylus geckos of the Socotra Archipelago.

    PubMed

    Gómez-Díaz, Elena; Sindaco, Roberto; Pupin, Fabio; Fasola, Mauro; Carranza, Salvador

    2012-08-01

    The Socotra Archipelago is an ancient continental fragment of Gondwanan origin and one of the most isolated landforms on Earth and a biodiversity hot spot. Yet, the biogeography and evolutionary history of its endemic fauna still remain largely overlooked. We investigate the origin, tempo and mode of diversification in the Hemidactylus geckos of the Socotra Archipelago. Concatenated and multilocus species coalescent analyses of Hemidactylus from Arabia and North Africa indicate that the Hemidactylus from Socotra do not form a monophyletic group and branch as three independent and well-supported clades instead. Both the chronogram inferred using the gene tree approach of BEAST and the age-calibrated multilocus species tree obtained using *BEAST suggest that the origin of Hemidactylus from Socotra may have involved a first vicariance event that occurred in the Early Miocene, followed by two independent transoceanic dispersal events that occurred more recently, during the Pliocene. Within Socotra, we analysed patterns of genetic diversity, the phylogeography and the demographic history in all seven nonintroduced species of Hemidactylus. Results based on two mitochondrial and two nuclear loci from 144 individuals revealed complex patterns of within-island diversification and high levels of intra-species genetic divergence. The interplay of both historical and ecological factors seems to have a role in the speciation process of this group of geckos. Interestingly, the case of H. forbesii and H. oxyrhinus, which inhabit the island of Abd al Kuri with an area of 133 km(2), may represent one of the most extreme cases of intra-island speciation in reptiles ever reported. PMID:22738330

  9. Interactions between Hair Cells Shape Spontaneous Otoacoustic Emissions in a Model of the Tokay Gecko's Cochlea

    PubMed Central

    Gelfand, Michael; Piro, Oreste; Magnasco, Marcelo O.; Hudspeth, A. J.

    2010-01-01

    Background The hearing of tetrapods including humans is enhanced by an active process that amplifies the mechanical inputs associated with sound, sharpens frequency selectivity, and compresses the range of responsiveness. The most striking manifestation of the active process is spontaneous otoacoustic emission, the unprovoked emergence of sound from an ear. Hair cells, the sensory receptors of the inner ear, are known to provide the energy for such emissions; it is unclear, though, how ensembles of such cells collude to power observable emissions. Methodology and Principal Findings We have measured and modeled spontaneous otoacoustic emissions from the ear of the tokay gecko, a convenient experimental subject that produces robust emissions. Using a van der Pol formulation to represent each cluster of hair cells within a tonotopic array, we have examined the factors that influence the cooperative interaction between oscillators. Conclusions and Significance A model that includes viscous interactions between adjacent hair cells fails to produce emissions similar to those observed experimentally. In contrast, elastic coupling yields realistic results, especially if the oscillators near the ends of the array are weakened so as to minimize boundary effects. Introducing stochastic irregularity in the strength of oscillators stabilizes peaks in the spectrum of modeled emissions, further increasing the similarity to the responses of actual ears. Finally, and again in agreement with experimental findings, the inclusion of a pure-tone external stimulus repels the spectral peaks of spontaneous emissions. Our results suggest that elastic coupling between oscillators of slightly differing strength explains several properties of the spontaneous otoacoustic emissions in the gecko. PMID:20559557

  10. Fiber Attachment Module Experiment

    NASA Technical Reports Server (NTRS)

    Agostini, Reinaldo J.

    2014-01-01

    Hollow Fiber Membrane Bioreactors (HFMB) are ideal systems for biological pretreatment of wastewater, however, optimization is still underway. The Fiber Attachment Module Experiment (FAME) allows the simultaneous testing of potential materials, treatments on these and varying inoculums. Polydimethylsiloxane (PDMS), the material chosen for its ideal oxygen permeation properties, was treated with 1 sodium hydroxide 0.1 M ether for 18 seconds and ultraviolet (UV) irradiation oxygen plasma (OP) exposure for 1 hour. Preliminary chemistry and visual data indicate promising treatments when using OP and sodium hydroxide as treatments for PDMS fibers; however, due to the biological nature of the experiment, time is a constraint. Sodium hydroxide treatment chemistry data shows nitrification is occurring as urea and ammonia are decreasing and nitrite is increasing. A higher amount of biofilm can also be observed for this particular case. During the final two weeks of the internship x-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR) and acridine orange (AO) cell counts will be employed for treatment effectiveness on the first batch of treatments (ether and sodium hydroxide). These same strategies will be used for the second batch of experiments due in four weeks (2nd week of August).

  11. Micromechanical die attachment surcharge

    DOEpatents

    Filter, William F.; Hohimer, John P.

    2002-01-01

    An attachment structure is disclosed for attaching a die to a supporting substrate without the use of adhesives or solder. The attachment structure, which can be formed by micromachining, functions purely mechanically in utilizing a plurality of shaped pillars (e.g. round, square or polygonal and solid, hollow or slotted) that are formed on one of the die or supporting substrate and which can be urged into contact with various types of mating structures including other pillars, a deformable layer or a plurality of receptacles that are formed on the other of the die or supporting substrate, thereby forming a friction bond that holds the die to the supporting substrate. The attachment structure can further include an alignment structure for precise positioning of the die and supporting substrate to facilitate mounting the die to the supporting substrate. The attachment structure has applications for mounting semiconductor die containing a microelectromechanical (MEM) device, a microsensor or an integrated circuit (IC), and can be used to form a multichip module. The attachment structure is particularly useful for mounting die containing released MEM devices since these devices are fragile and can otherwise be damaged or degraded by adhesive or solder mounting.

  12. Longitudinal and lateral-directional static aerodynamic characteristics of an unpowered escape system extraction rocket model with attached launch tubes

    NASA Technical Reports Server (NTRS)

    Huffman, J. K.; Fox, C. H., Jr.; Satterthwaite, R. E.

    1977-01-01

    An escape system extraction rocket proposed for use on the Rotor Systems Research Aircraft was tested at Mach numbers of 0.1 and 0.3 through an angle of attack range from -2 deg to 102 deg and an angle of sideslip range from 0 deg to 15 deg in the Langley 7- by 10-foot high speed tunnel. The data are presented without analysis.

  13. Attachment and early maltreatment.

    PubMed

    Egeland, B; Sroufe, L A

    1981-03-01

    Attachment outcomes of 31 maltreatment cases (extreme neglect or abuse) selected from a total poverty sample of 267 high-risk mothers were compared at 12 and 18 months to a subsample of 33 cases with a history of excellent care. In accordance with the Bowlby-Ainsworth hypothesis, the maltreatment group was characterized by a low proportion of secure attachment (Ainsworth's group B) at 12 months (38% compared to 75% in the excellent care group and 55% in the remaining total sample); however, differences at 18 months were not significant. Specifically, 50% of the cases with a history of neglect were in Ainsworth's group C (anxious/resistant attachment) at 12 months, compared to usual reports of approximately 10% and compared to 21% in the total poverty sample. Patterns of attachment between 12 and 18 months remained stable for the mother-infant pairs in the excellent care group, however, 52% of the mistreated infants changed classifications. For the neglect subgroup there was considerable movement toward Ainsworth's group A (anxious/avoidant attachment) at 18 months and some movement toward group B. An examination of the case histories of mother-infant pairs indicated that changes in attachment between 12 and 18 months were related to changing life events, support from family, and out-of-home care. These findings are highly tentative as were the findings which suggested that secure attachment within the maltreatment group was associated with the presence of a supportive family member, less chaotic life-style, and, in some instances, a more robust infant. PMID:7238152

  14. Jettisoning ballast or fuel? Caudal autotomy and locomotory energetics of the Cape dwarf gecko Lygodactylus capensis (Gekkonidae).

    PubMed

    Fleming, Patricia A; Verburgt, Luke; Scantlebury, Mike; Medger, Katarina; Bateman, Philip W

    2009-01-01

    Many lizard species will shed their tail as a defensive response (e.g., to escape a putative predator or aggressive conspecific). This caudal autotomy incurs a number of costs as a result of loss of the tail itself, loss of resources (i.e., stored in the tail or due to the cost of regeneration), and altered behavior. Few studies have examined the metabolic costs of caudal autotomy. A previous study demonstrated that geckos can move faster after tail loss as a result of reduced weight or friction with the substrate; however, there are no data for the effects of caudal autotomy on locomotory energetics. We examined the effect of tail loss on locomotory costs in the Cape dwarf gecko Lygodactylus capensis ( approximately 0.9 g) using a novel method for collecting data on small lizards, a method previously used for arthropods. We measured CO(2) production during 5-10 min of exhaustive exercise (in response to stimulus) and during a 45-min recovery period. During exercise, we measured speed (for each meter moved) as well as total distance traveled. Contrary to our expectations, tailless geckos overall expended less effort in escape running, moving both slower and for a shorter distance, compared with when they were intact. Tailless geckos also exhibited lower excess CO(2) production (CO(2) production in excess of normal resting metabolic rate) during exercising. This may be due to reduced metabolically active tissue (tails represent 8.7% of their initial body mass). An alternative suggestion is that a change in energy substrate use may take place after tail loss. This is an intriguing finding that warrants future biochemical investigation before we can predict the relative costs of tail loss that lizards might experience under natural conditions. PMID:19758092

  15. Examining the Meaning Attached to Mental Illness and Mental Health Services Among Justice System-Involved Youth and Their Parents

    PubMed Central

    Watson, Amy C.; Kelly, Brian L.; Vidalon, Theresa M.

    2010-01-01

    A large percentage of youth involved in the juvenile justice system experience mental health problems, yet many do not receive mental health care. In this study, we used a process-focused framework of mental health decision making to gain insight into the use of mental health services among these youth. In-depth interviews were conducted with nine youth and nine parents participating in a program servicing youth with mental health problems who have been in detention. Themes related to problem recognition, the decision to seek and participate in services, subjective norms, and juvenile justice system involvement emerged. Most families acknowledged their youth was having problems, but few defined those problems in mental health terms. This did not prevent them from seeking services, although some were not able to access adequate services until the justice system became involved. Participants were aware of negative attitudes about mental illness, and might have limited their social networks to shield themselves. PMID:19638602

  16. Methanol production from eucalyptus wood chips. Attachment VIII. The wood-fueled gasification system, Evergreen Energy Corporation's final engineering report

    SciTech Connect

    Fishkind, H.H.

    1982-06-01

    Evergreen Energy Corporation provided projected cost and operating data on the Evergreen/Texaco entrained-bed wood gasification system currently under development as an alternative to the state-of-the-art fixed-bed wood gasification system proposed by Davy McKee. Overall capital costs for the total plant remain about the same at approx. $250 million. The Evergreen/Texaco system will provide significant capital cost savings in the gasifiers, gas cleanup, and waste water treatment sections, and eliminate the need for a large off-site wood-fired power boiler. These reductions are offset by higher investments in the feedstock preparation, drying, and feeding section plus the need for a larger air separation plant and compressor to supply oxygen at high pressure to the gasifier.

  17. Cone-like rectification properties of cGMP-gated channels in transmutated retinal photoreceptors of nocturnal geckoes.

    PubMed

    Vellani, Vittorio; Giacomoni, Chiara

    2014-01-01

    Photoreceptors of nocturnal geckoes are scotopic, with rod-shaped outer segments, and sensitivities to light similar to the one of retinal rods from other species of lower vertebrates. However, these cells are not rods, but they originated from cones of ancestral diurnal geckoes with pure-cone retinas, after being forced to adapt to a nocturnal behavior. Several interesting adaptations of these rod-like cones have been studied to date; molecular biology and functional studies confirmed that several proteins of the phototransductive cascade display structural and functional properties that indicate their origin from cones rather than from rods. In this paper, we investigate, with whole cell voltage clamp in the photoreceptor detached outer segment preparation, the voltage rectification properties of cGMP-gated channels in three species, Gekko gecko, Tarentola mauritanica, and Hemidactylus frenatus. We show that the current-voltage properties in the physiological voltage range are reminiscent of the ones of cGMP-gated channels from cones rather than from rods of other cold-blooded vertebrates. The origin and the relevance of the mechanisms investigated are discussed. PMID:25506076

  18. Cone-Like Rectification Properties of cGMP-Gated Channels in Transmutated Retinal Photoreceptors of Nocturnal Geckoes

    PubMed Central

    Giacomoni, Chiara

    2014-01-01

    Photoreceptors of nocturnal geckoes are scotopic, with rod-shaped outer segments, and sensitivities to light similar to the one of retinal rods from other species of lower vertebrates. However, these cells are not rods, but they originated from cones of ancestral diurnal geckoes with pure-cone retinas, after being forced to adapt to a nocturnal behavior. Several interesting adaptations of these rod-like cones have been studied to date; molecular biology and functional studies confirmed that several proteins of the phototransductive cascade display structural and functional properties that indicate their origin from cones rather than from rods. In this paper, we investigate, with whole cell voltage clamp in the photoreceptor detached outer segment preparation, the voltage rectification properties of cGMP-gated channels in three species, Gekko gecko, Tarentola mauritanica, and Hemidactylus frenatus. We show that the current-voltage properties in the physiological voltage range are reminiscent of the ones of cGMP-gated channels from cones rather than from rods of other cold-blooded vertebrates. The origin and the relevance of the mechanisms investigated are discussed. PMID:25506076

  19. Autism and Attachment: The Attachment Q-Sort

    ERIC Educational Resources Information Center

    Rutgers, Anna H.; Van Ijzendoorn, Marinus H.; Bakermans-Kranenburg, Marian J.; Swinkels, Sophie H. N.

    2007-01-01

    Children with autism are able to show secure attachment behaviours to their parents/caregivers. Most studies on attachment in children with autism used a (modified) Strange Situation Procedure (SSP) to examine attachment security. An advantage of the Attachment Q-Sort (AQS) over the SSP is that it can be attuned to the secure-base behaviour of…

  20. Methanol production from eucalyptus wood chips. Attachment IV. Health and safety aspects of the eucalypt biomass to methanol energy system

    SciTech Connect

    Fishkind, H.H.

    1982-06-01

    The basic eucalyptus-to-methanol energy process is described and possible health and safety risks are identified at all steps of the process. The toxicology and treatment for exposure to these substances are described and mitigating measures are proposed. The health and safety impacts and risks of the wood gasification/methanol synthesis system are compared to those of the coal liquefaction and conversion system. The scope of this report includes the health and safety risks of workers (1) in the laboratory and greenhouse, where eucalyptus seedlings are developed, (2) at the biomass plantation, where these seedlings are planted and mature trees harvested, (3) transporting these logs and chips to the refinery, (4) in the hammermill, where the logs and chips will be reduced to small particles, (5) in the methanol synthesis plant, where the wood particles will be converted to methanol, and (6) transporting and dispensing the methanol. Finally, the health and safety risks of consumers using methanol is discussed.

  1. Superego: an attachment perspective.

    PubMed

    Holmes, Jeremy

    2011-10-01

    With the help of attachment theory and research, the paper attempts to broaden and build on classical and current views on the superego. Attachment theory's epigenetic approach and the concept of the subliminal superego are described. The superego, it is argued, is as much concerned with safety as sex. The superego is 'heir', not just to the Oedipus complex or Klein's pre-oedipal constellation, but also to the attachment relationship. Under favourable developmental conditions a 'mature superego' emerges, facilitating, in the presence of an internal secure base, maturational boundary crossings towards adult sexuality. In the light of the above, the paper reviews Lear's updating of Strachey's model of psychic change and explores the concept of transgression in relation to the 'professional superego', its development and maturation. Theoretical arguments are illustrated with clinical examples. PMID:22014367

  2. Adult attachment interviews of women from low-risk, poverty, and maltreatment risk samples: comparisons between the hostile/helpless and traditional AAI coding systems.

    PubMed

    Frigerio, Alessandra; Costantino, Elisabetta; Ceppi, Elisa; Barone, Lavinia

    2013-01-01

    The main aim of this study was to investigate the correlates of a Hostile-Helpless (HH) state of mind among 67 women belonging to a community sample and two different at-risk samples matched on socio-economic indicators, including 20 women from low-SES population (poverty sample) and 15 women at risk for maltreatment being monitored by the social services for the protection of juveniles (maltreatment risk sample). The Adult Attachment Interview (AAI) protocols were reliably coded blind to the samples' group status. The rates of HH classification increased in relation to the risk status of the three samples, ranging from 9% for the low-risk sample to 60% for the maltreatment risk sample to 75% for mothers in the maltreatment risk sample who actually maltreated their infants. In terms of the traditional AAI classification system, 88% of the interviews from the maltreating mothers were classified Unresolved/Cannot Classify (38%) or Preoccupied (50%). Partial overlapping between the 2 AAI coding systems was found, and discussion concerns the relevant contributions of each AAI coding system to understanding of the intergenerational transmission of maltreatment. PMID:23724955

  3. Internal pipe attachment mechanism

    DOEpatents

    Bast, Richard M.; Chesnut, Dwayne A.; Henning, Carl D.; Lennon, Joseph P.; Pastrnak, John W.; Smith, Joseph A.

    1994-01-01

    An attachment mechanism for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection.

  4. Internal pipe attachment mechanism

    DOEpatents

    Bast, R.M.; Chesnut, D.A.; Henning, C.D.; Lennon, J.P.; Pastrnak, J.W.; Smith, J.A.

    1994-12-13

    An attachment mechanism is described for repairing or extending fluid carrying pipes, casings, conduits, etc. utilizing one-way motion of spring tempered fingers to provide a mechanical connection between the attachment mechanism and the pipe. The spring tempered fingers flex to permit insertion into a pipe to a desired insertion depth. The mechanical connection is accomplished by reversing the insertion motion and the mechanical leverage in the fingers forces them outwardly against the inner wall of the pipe. A seal is generated by crushing a sealing assembly by the action of setting the mechanical connection. 6 figures.

  5. Ladder attachment platform

    DOEpatents

    Swygert,; Richard, W [Springfield, SC

    2012-08-28

    A ladder attachment platform is provided that includes a base for attachment to a ladder that has first and second side rails and a plurality of rungs that extend between in a lateral direction. Also included is a user platform for having a user stand thereon that is carried by the base. The user platform may be positioned with respect to the ladder so that it is not located between a first plane that extends through the first side rail and is perpendicular to the lateral direction and a second plane that extends through the second side rail and is perpendicular to the lateral direction.

  6. Attachment Organization and History of Suicidal Behavior in Clinical Adolescents.

    ERIC Educational Resources Information Center

    Adam, Kenneth S.; And Others

    1996-01-01

    Adolescents in psychiatric treatment (N=133) participated in a case-comparison study investigating the association of attachment patterns with a history of suicidal behaviors. Attachment patterns were assessed using the Adult Attachment Interview. In accordance with definitions provided in the scoring system, 86% of case and 78% of comparison…

  7. Three-dimensional distribution of polymorphs and magnesium in a calcified underwater attachment system by diffraction tomography

    PubMed Central

    Leemreize, Hanna; Almer, Jonathan D.; Stock, Stuart R.; Birkedal, Henrik

    2013-01-01

    Biological materials display complicated three-dimensional hierarchical structures. Determining these structures is essential in understanding the link between material design and properties. Herein, we show how diffraction tomography can be used to determine the relative placement of the calcium carbonate polymorphs calcite and aragonite in the highly mineralized holdfast system of the bivalve Anomia simplex. In addition to high fidelity and non-destructive mapping of polymorphs, we use detailed analysis of X-ray diffraction peak positions in reconstructed powder diffraction data to determine the local degree of Mg substitution in the calcite phase. These data show how diffraction tomography can provide detailed multi-length scale information on complex materials in general and of biomineralized tissues in particular. PMID:23804437

  8. Attachment of Agrobacteria to Grape Cells †

    PubMed Central

    Pu, Xin-An; Goodman, R. N.

    1993-01-01

    The presence of the Ti plasmid favorably influences the attachment of agrobacteria to grape callus cells, especially during the early stages of a 2-h incubation. Agrobacterium strains attached to a similar extent to both the crown gall-resistant cultivar (Catawba), Vitis labruscana, and the crown gall-susceptible cultivar (Chancellor), Vitis sp. Attachment of the virulent strain to grape callus cells is blocked by the avirulent strain HLB-2 in both the tissue culture cell suspension and the seedling root systems. PMID:16349016

  9. The interaction of fetuin with phosphatidylcholine monolayers. Characterization of a lipoprotein membrane system suitable for the attachment of myxoviruses

    PubMed Central

    Tiffany, J. M.; Blough, H. A.

    1970-01-01

    1. An artificial membrane system was formed by spreading at air/water and oil/water interfaces, by using phosphatidylcholine and the glycoprotein fetuin (mol.wt. 48400). 2. The plot of increase of interfacial pressure against amount of protein added beneath a monomolecular film of phosphatidylcholine showed two discontinuities, corresponding to the completion of two distinct layers of protein: (a) largely denatured and closely associated with the polar head groups of phosphatidylcholine, possibly with penetration of non-polar protein groups between the phosphatidylcholine molecules and (b) an additional adsorbed layer of substantially native fetuin in either a close-packed or open-lattice array. A more compactly organized membrane was apparently formed at pH7.4 with 1mm-Mg2+ in the aqueous phase than without Mg2+; at 15mm-Mg2+, more random adsorption of protein appeared to take place. Qualitatively similar results were obtained at pH5.1 with 1mm-Mg2+. Closer initial packing of the phosphatidylcholine layer decreased both the magnitude of the interfacial pressure change and the amounts of protein bound in the two layers. 3. The amount of N-acetylneuraminic acid released by neuraminidase (EC 3.2.1.18) in the subphase was measured at pH5.1; a mean distribution of 9.7×1013 residues/cm2 was calculated for the completed second protein layer. PMID:5420053

  10. Attachment in integrative neuroscientific perspective.

    PubMed

    Hruby, Radovan; Hasto, Jozef; Minarik, Peter

    2011-01-01

    Attachment theory is a very influential general concept of human social and emotional development, which emphasizes the role of early mother-infant interactions for infant's adaptive behavioural and stress copying strategies, personality organization and mental health. Individuals with disrupted development of secure attachment to mother/primary caregiver are at higher risk of developing mental disorders. This theory consists of the complex developmental psycho-neurobiological model of attachment and emerges from principles of psychoanalysis, evolutionary biology, cognitive-developmental psychology, ethology, physiology and control systems theory. The progress of modern neuroscience enables interpretation of neurobiological aspects of the theory as multi-level neural interactions and functional development of important neural structures, effects of neuromediattors, hormones and essential neurobiological processes including emotional, cognitive, social interactions and the special key role of mentalizing. It has multiple neurobiological, neuroendocrine, neurophysiological, ethological, genetic, developmental, psychological, psychotherapeutic and neuropsychiatric consequences and is a prototype of complex neuroscientific concept as interpretation of modern integrated neuroscience. PMID:21552202

  11. Attachment and Personality Disorders

    ERIC Educational Resources Information Center

    Sinha, Preeti; Sharan, Pratap

    2007-01-01

    Personality disorders (PDs) arise from core psychopathology of interpersonal relationships and understanding of self and others. The distorted representations of self and others, as well as unhealthy relationships that characterize persons with various PDs, indicate the possibility that persons with PDs have insecure attachment. Insecure…

  12. Reversal of flagellar rotation is important in initial attachment of Escherichia coli to glass in a dynamic system with high- and low-ionic-strength buffers.

    PubMed

    McClaine, Jennifer W; Ford, Roseanne M

    2002-03-01

    The attachment rates of wild-type, smooth-swimming, tumbly, and paralyzed Escherichia coli to glass was measured at fluid velocities of 0.0044 and 0.044 cms(-1) (corresponding to shear rates of 0.34 and 3.4 s(-1), respectively), in 0.02 and 0.2 M buffer solutions. At the highest ionic strength, we did not observe a significant difference in the attachment rate of wild-type and paralyzed cells at either fluid velocity. However, when the ionic strength was reduced, paralyzed bacteria attached at rates 4 and 10 times lower than that of the wild type under fluid velocities of 0.0044 and 0.044 cms(-1), respectively. This suggested that the rotation of the flagella assisted in attachment. We then compared the attachment rates of smooth-swimming (counterclockwise rotation only) and tumbly (clockwise rotation only) cells to the wild type to determine whether the direction of rotation was important to cell attachment. At 0.0044 cms(-1), the smooth-swimming cells attached at rates similar to that of the wild type in both buffer solutions but significantly less at the higher fluid velocity. Tumbly cells attached at much lower rates under all conditions. Thus, the combination of clockwise and counterclockwise flagellar rotation and their coupling appeared to be important in cell attachment. We considered a number of hypotheses to interpret these observations, including a residence time analysis and a comparison of traditional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory to soft-particle theory. PMID:11872478

  13. High Prevalence of Insecure Attachment in Patients with Primary Hypertension.

    PubMed

    Balint, Elisabeth M; Gander, Manuela; Pokorny, Dan; Funk, Alexandra; Waller, Christiane; Buchheim, Anna

    2016-01-01

    Hypertension is a major cardiovascular (CV) risk factor and is predicted by heightened CV reactivity to stress in healthy individuals. Patients with hypertension also show an altered stress response, while insecure attachment is linked to a heightened stress reactivity as well. This is the first study aiming to assess attachment representations in patients with primary hypertension and to investigate their CV responses when their attachment system is activated. We studied 50 patients (38 men, 12 women) with primary hypertension. The Adult Attachment Projective Picture System (AAP), a widely used and validated interview, was performed to measure the patients' attachment representations, and to activate their attachment system. Blood pressure and heart rate were measured after 10 min at rest prior to and directly after the AAP interview. Mood and state anxiety were assessed using the Multidimensional Mood State Questionnaire (MDBF) and the State Trait Anxiety Inventory-State (STAI-S) before and after the experiment. The prevalence of insecure attachment (dismissing, preoccupied, unresolved) in hypertensive patients was predominant (88%), while in non-clinical populations, only about 50% of individuals had insecure attachment patterns. Blood pressure (p < 0.001), heart rate (p = 0.016), and rate pressure product (p < 0.001) significantly increased in response to the attachment interview. Secure attached patients showed the highest rise in systolic blood pressure (p = 0.020) and the lowest heart rate compared to the other attachment groups (p = 0.043). However, attachment representation showed no significant group or interaction effects on diastolic blood pressure (DBP) and rate pressure product. Insecure attachment was highly over-represented in our sample of patients with primary hypertension. Additionally, a robust CV response to the attachment-activating stimulus was observed. Our data suggest that insecure attachment is significantly linked to primary hypertension

  14. High Prevalence of Insecure Attachment in Patients with Primary Hypertension

    PubMed Central

    Balint, Elisabeth M.; Gander, Manuela; Pokorny, Dan; Funk, Alexandra; Waller, Christiane; Buchheim, Anna

    2016-01-01

    Hypertension is a major cardiovascular (CV) risk factor and is predicted by heightened CV reactivity to stress in healthy individuals. Patients with hypertension also show an altered stress response, while insecure attachment is linked to a heightened stress reactivity as well. This is the first study aiming to assess attachment representations in patients with primary hypertension and to investigate their CV responses when their attachment system is activated. We studied 50 patients (38 men, 12 women) with primary hypertension. The Adult Attachment Projective Picture System (AAP), a widely used and validated interview, was performed to measure the patients' attachment representations, and to activate their attachment system. Blood pressure and heart rate were measured after 10 min at rest prior to and directly after the AAP interview. Mood and state anxiety were assessed using the Multidimensional Mood State Questionnaire (MDBF) and the State Trait Anxiety Inventory-State (STAI-S) before and after the experiment. The prevalence of insecure attachment (dismissing, preoccupied, unresolved) in hypertensive patients was predominant (88%), while in non-clinical populations, only about 50% of individuals had insecure attachment patterns. Blood pressure (p < 0.001), heart rate (p = 0.016), and rate pressure product (p < 0.001) significantly increased in response to the attachment interview. Secure attached patients showed the highest rise in systolic blood pressure (p = 0.020) and the lowest heart rate compared to the other attachment groups (p = 0.043). However, attachment representation showed no significant group or interaction effects on diastolic blood pressure (DBP) and rate pressure product. Insecure attachment was highly over-represented in our sample of patients with primary hypertension. Additionally, a robust CV response to the attachment-activating stimulus was observed. Our data suggest that insecure attachment is significantly linked to primary hypertension

  15. Systematics, biogeography, and evolution of Hemidactylus geckos (Reptilia: Gekkonidae) elucidated using mitochondrial DNA sequences.

    PubMed

    Carranza, S; Arnold, E N

    2006-02-01

    With more than 80 species inhabiting all warm continental land masses and hundreds of intervening continental and oceanic islands, Hemidactylus geckos are one of the most species-rich and widely distributed of all reptile genera. They consequently represent an excellent model for biogeographic, ecological, and evolutionary studies. A molecular phylogeny for Hemidactylus is presented here, based on 702 bp of mtDNA (303 bp cytochrome b and 399 bp 12S rRNA) from 166 individuals of 30 species of Hemidactylus plus Briba brasiliana, Cosymbotus platyurus, and several outgroups. The phylogeny indicates that Hemidactylus may have initially undergone rapid radiation, and long-distance dispersal is more extensive than in any other reptilian genus. In the last 15 My, African lineages have naturally crossed the Atlantic Ocean at least twice. They also colonized the Gulf of Guinea, Cape Verde and Socotra islands, again sometimes on more than one occasion. Many extensive range extensions have occurred much more recently, sometimes with devastating consequences for other geckos. These colonizations are likely to be largely anthropogenic, involving the 'weedy' commensal species, H. brookii s. lat, H. mabouia, H. turcicus, H. garnotii, and H. frenatus. These species collectively have colonized the Mediterranean region, tropical Africa, much of the Americas and hundreds of islands in the Pacific, Indian, and Atlantic oceans. Five well-supported clades are discernable in Hemidactylus, with the African H. fasciatus unallocated. 1. Tropical Asian clade: (Cosymbotus platyurus (H. bowringii, H. karenorum, H. garnotii)) (H. flaviviridis (Asian H. brookii, H. frenatus)). 2. African H. angulatus and Caribbean H. haitianus. 3. Arid clade, of NE Africa, SW Asia, etc.: (H. modestus (H. citernii, H. foudai)) (H. pumilio (H. granti, H. dracaenacolus) (H. persicus, H. macropholis, H. robustus, H. turcicus (H. oxyrhinus (H. homoeolepis, H. forbesii))). 4. H. mabouia clade (H. yerburii, H. mabouia

  16. Development of an attached growth reactor for NH₄-N removal at a drinking water supply system in Kathmandu Valley, Nepal.

    PubMed

    Khanitchaidecha, Wilawan; Shakya, Maneesha; Nakano, Yuichi; Tanaka, Yasuhiro; Kazama, Futaba

    2012-01-01

    Higher concentrations of ammonium (NH(4)-N) and iron (Fe) than a standard for drinking are typical characteristics of groundwater in the study area. To remove NH(4)-N and Fe, the drinking water supply system in this study consists of a series of treatment units (i.e., aeration and sedimentation, filtration, and chlorination); however, NH(4)-N in treated water is higher than a standard for drinking (i.e., <1.5 mg NH(4)-N/L). The objective of this study, therefore, is to develop an attached growth system containing a fiber carrier for reducing NH(4)-N concentration within a safe level in the treated water. To avoid the need of air supply for nitrification, groundwater was continuously dripped through the reactor. It made the system simple operation and energy efficient. Effects of reactor design (reactor length and carrier area) were studied to achieve a high NH(4)-N removal efficiency. In accordance with raw groundwater characteristics in the area, effects of low inorganic carbon (IC) and phosphate (PO(4)-P) and high Fe on the removal efficiency were also investigated. The results showed a significant increase in NH(4)-N removal efficiency with reactor length and carrier area. A low IC and PO(4)-P had no effect on NH(4)-N removal, whereas a high Fe decreased the efficiency significantly. The first 550 days operation of a pilot-scale reactor installed in the drinking water supply system showed a gradual increase in the efficiency, reaching to 95-100%, and stability in the performance even with increased flow rate from 210 to 860 L/day. The high efficiency of the present work was indicated because only less than 1 mg of NH(4)-N/L was left over in the treated water. PMID:22416868

  17. A Cross-Cultural Study of Mother-Infant Interaction between Japan and Korea (4): Cross-Cultural Comparisons of Human Attachment Systems among Five Asian and Western Countries.

    ERIC Educational Resources Information Center

    Fujinaga, Tamotsu; And Others

    This study examined culture-specific attachment systems in Japan (including an Okinawan sample), Korea, China, United States, and the United Kingdom, using a questionnaire to measure the relative importance of various categories of interpersonal relations. Subjects were male and female university students and fathers and mothers of kindergarten…

  18. WP-2 attached payload accommodations

    NASA Technical Reports Server (NTRS)

    Scheib, Jim

    1992-01-01

    The presentation provides an overview of the current SSFP attached payload accommodations on the U.S. truss. The overview includes discussions on the four attach sites, the power architecture, thermal control, DMS provisions, and the mechanical attach mechanism. The presentation concludes with a description of a McDonnell Douglas concept for an attached payload pallet designed to take advantage of the four sites and existing SSF hardware. This presentation should provide the payload community with a basic understanding of the SSF attached payload utility ports and aid in attached payload concept development.

  19. Leadership and attachment theory.

    PubMed

    Bresnahan, Christopher G; Mitroff, Ian I

    2007-09-01

    Comments on the six articles contained in the special issue of the American Psychologist (January 2007) devoted to leadership, written by W. Bennis; S. J. Zaccaro; V. H. Vroom and A. G. Yago; B. J. Avolio; R. J. Sternberg; and R. J. Hackman and R. Wageman. The current authors opine that the inclusion of attachment theory in the study of leadership could strengthen leadership theories as a whole. PMID:17874909

  20. A new species of dwarf gecko in the genus Lygodactylus (squamata: Gekkonidae) from central Kenya.

    PubMed

    Malonza, Patrick K; Granthon, Carolina; Williams, Dean A

    2016-01-01

    A new species of Lygodactylus gecko (L. wojnowskii sp. nov.) is described from the vicinity of Chogoria Town on the eastern lower slopes of Mt. Kenya in central Kenya. A phylogeny based on mitochondrial and nuclear DNA shows that the proposed new taxon is distinct within the Lygodactylus picturatus group and is the sister lineage to L. mombasicus and L. kimhowelli. It is morphologically very similar to both L. mombasicus and L. keniensis but its dorsal coloration and pattern is different. Its dorsum is grey with dark stripes while its head has black and white stripes that form a Y-shaped mark. While the male throat pattern is similar to that of L. mombasicus, that of the female is like that of females and some males of Lygodactylus keniensis. Lygodactylus wojnowskii sp. nov. has a higher number of post-postmental scales (6) than do its close relatives (5). The new species is distributed on the lower slopes of mid-altitude areas on eastern Mt. Kenya, but it may occur in other areas at similar elevations in central Kenya. It is associated with short, scattered trees within agricultural areas. It has not yet been recorded within the protected Chogoria forest block of Mt. Kenya forest. It is likely present in Mwea National Reserve as it occurs in nearby areas. PMID:27395510

  1. Multilocus phylogeography reveals nested endemism in a gecko across the monsoonal tropics of Australia.

    PubMed

    Moritz, C; Fujita, M K; Rosauer, D; Agudo, R; Bourke, G; Doughty, P; Palmer, R; Pepper, M; Potter, S; Pratt, R; Scott, M; Tonione, M; Donnellan, S

    2016-03-01

    Multilocus phylogeography can uncover taxonomically unrecognized lineage diversity across complex biomes. The Australian monsoonal tropics include vast, ecologically intact savanna-woodland plains interspersed with ancient sandstone uplands. Although recognized in general for its high species richness and endemism, the biodiversity of the region remains underexplored due to its remoteness. This is despite a high rate of ongoing species discovery, especially in wetter regions and for rock-restricted taxa. To provide a baseline for ongoing comparative analyses, we tested for phylogeographic structure in an ecologically generalized and widespread taxon, the gecko Heteronotia binoei. We apply coalescent analyses to multilocus sequence data (mitochondrial DNA and eight nuclear DNA introns) from individuals sampled extensively and at fine scale across the region. The results demonstrate surprisingly deep and geographically nested lineage diversity. Several intra-specific clades previously shown to be endemic to the region were themselves found to contain multiple, short-range lineages. To infer landscapes with concentrations of unique phylogeographic diversity, we probabilistically estimate the ranges of lineages from point data and then, combining these estimates with the nDNA species tree, estimate phyloendemism across the region. Highest levels of phyloendemism occur in northern Top End, especially on islands, across the topographically complex Arnhem escarpment, and across the sandstone ranges of the western Gulf region. These results drive home that deep phylogeographic structure is prevalent in tropical low-dispersal taxa, even ones that are ubiquitous across geography and habitats. PMID:26671627

  2. Mitochondrial introgression via ancient hybridization, and systematics of the Australian endemic pygopodid gecko genus Delma.

    PubMed

    Brennan, Ian G; Bauer, Aaron M; Jackman, Todd R

    2016-01-01

    Of the more than 1500 species of geckos found across six continents, few remain as unfamiliar as the pygopodids - Family Pygopodidae (Gray, 1845). These gekkotans are limited to Australia (44 species) and New Guinea (2 species), but have diverged extensively into the most ecologically diverse limbless radiation save Serpentes. Current phylogenetic understanding of the family has relied almost exclusively on two works, which have produced and synthesized an immense amount of morphological, geographical, and molecular data. However, current interspecific relationships within the largest genus Delma Gray 1831 are based chiefly upon data from two mitochondrial loci (16s, ND2). Here, we reevaluate the interspecific relationships within the genus Delma using two mitochondrial and four nuclear loci (RAG1, MXRA5, MOS, DYNLL1), and identify points of strong conflict between nuclear and mitochondrial genomic data. We address mito-nuclear discordance, and remedy this conflict by recognizing several points of mitochondrial introgression as the result of ancient hybridization events. Owing to the legacy value and intraspecific informativeness, we suggest the continued use of ND2 as a phylogenetic marker. Results identify strong support for species groups, but relationships among these clades, and the placement of several enigmatic taxa remain uncertain. We suggest a more careful review of Delma australis and the 'northwest Australia' clade. Accurately assessing and addressing species richness and relationships within this endemic Australian Gekkotan genus is relevant for understanding patterns of squamate speciation across the region. PMID:26505536

  3. Multimodal dispersal during the range expansion of the tropical house gecko Hemidactylus mabouia

    PubMed Central

    Short, Kristen H; Petren, Kenneth

    2011-01-01

    Dispersal influences both the ecological and evolutionary dynamics of range expansion. While some studies have demonstrated a role for human-mediated dispersal during invasion, the genetic effects of such dispersal remain to be understood, particularly in terrestrial range expansions. In this study, we investigated multimodal dispersal during the range expansion of the invasive gecko Hemidactylus mabouia in Florida using 12 microsatellite loci. We investigated dispersal patterns at the regional scale (metropolitan areas), statewide scale (state of Florida), and global scale (including samples from the native range). Dispersal was limited at the smallest, regional scale, within metropolitan areas, as reflected by the presence of genetic structure at this scale, which is in agreement with a previous study in this same invasion at even smaller spatial scales. Surprisingly, there was no detectable genetic structure at the intermediate statewide scale, which suggests dispersal is not limited across the state of Florida. There was evidence of genetic differentiation between Florida and other areas where H. mabouia occurs, so we concluded that at the largest scale, dispersal was limited. Humans likely contributed to patterns of dispersal at all three scales but in different ways. Infrequent low-volume dispersal has occurred within regions, frequent high-volume dispersal has occurred across the state, and infrequent long-distance dispersal has occurred among continents at the global scale. This study highlights the importance of considering different modes of dispersal at multiple spatial scales to understand the dynamics of invasion and range expansion. PMID:22393494

  4. Neural substrates for sexual and thermoregulatory behavior in the male leopard gecko, Eublepharis macularius.

    PubMed

    Edwards, Nora; Kriegsfeld, Lance; Crews, David

    2004-12-10

    The preoptic area-anterior hypothalamus (POAH) continuum is critical for the integration of environmental, physiological, and behavioral cues associated with reproduction in vertebrates. In the present study, radiofrequency lesions in the POAH abolished sexual behavior in the leopard gecko (Eublepharis macularius). Furthermore, results suggest a differential effect of POAH lesions on those behaviors regarded as appetitive (tail vibration and grip) and those regarded as consummatory (mounting and copulation), with consummatory behaviors being affected to a greater extent. E. macularius is an ectothermic vertebrate that modulates body temperature behaviorally relative to ambient temperature. In vertebrates, the POAH is also an important integrator of thermoregulation. Thus, the present study investigated whether lesions that disrupt reproductive behavior also disrupt body temperature regulation. While virtually all males displayed diurnal rhythms in thermoregulatory behavior prior to surgery, this pattern was abolished in a small proportion of animals bearing POAH lesions. Lesions that abolished thermoregulatory rhythms involved the suprachiasmatic nucleus (SCN), whereas lesions confined to the POAH, while dramatically influencing sexual behavior, did not affect thermoregulatory rhythms or temperature set point. Together, these findings identify the POAH as an important neural locus regulating sexual behavior but not thermoregulation and suggest that the SCN acts as a pacemaker controlling daily behavioral temperature regulation in this species. PMID:15533318

  5. Effects of salicylates and aminoglycosides on spontaneous otoacoustic emissions in the Tokay gecko.

    PubMed

    Stewart, C E; Hudspeth, A J

    2000-01-01

    The high sensitivity and sharp frequency discrimination of hearing depend on mechanical amplification in the cochlea. To explore the basis of this active process, we examined the pharmacological sensitivity of spontaneous otoacoustic emissions (SOAEs) in a lizard, the Tokay gecko. In a quiet environment, each ear produced a complex but stable pattern of emissions. These SOAEs were reversibly modulated by drugs that affect mammalian otoacoustic emissions, the salicylates and the aminoglycoside antibiotics. The effect of a single i.p. injection of sodium salicylate depended on the initial power of the emissions: ears with strong control SOAEs displayed suppression at all frequencies, whereas those with weak control emissions showed enhancement. Repeated oral administration of acetylsalicylic acid reduced all emissions. Single i.p. doses of gentamicin or kanamycin suppressed SOAEs below 2.6 kHz, while modulating those above 2.6 kHz in either of two ways. For ears whose emission power at 2.6-5.2 kHz encompassed more than half of the total, individual emissions displayed facilitation as great as 35-fold. For the remaining ears, emissions dropped to as little as one-sixth of their initial values. The similarity of the responses of reptilian and mammalian cochleas to pharmacological intervention provides further evidence for a common mechanism of cochlear amplification. PMID:10618439

  6. Incubation temperature affects the behavior of adult leopard geckos (Eublepharis macularius).

    PubMed

    Flores, D; Tousignant, A; Crews, D

    1994-06-01

    The leopard gecko has temperature-dependent sex determination (TSD); females are predominantly produced when incubated at 26 degrees C (100%), 30 degrees C (70%), and 34 degrees C (95%), whereas males are predominantly produced at 32.5 degrees C (75%). Exogenous estradiol can override the effect of temperature on sex determination. To compare temperature-determined females with hormone-determined females, eggs from the male-biased temperature were treated with estradiol benzoate during incubation. As adults, animals from a male-biased incubation temperature were more likely to exhibit aggression than animals from female-biased incubation temperatures. Furthermore, females from a male-biased incubation temperature tended to be less attractive than females from female-biased temperatures. Hormone-determined females were both attractive and aggressive. This suggests that incubation temperature is an important development determinant of adult aggressiveness and attractiveness. The 26 degrees C animals ovariectomized on the day of hatch exhibited more frequent aggression and were unreceptive to males, indicating that postnatal ovarian hormones also play a role in adult sociosexual behaviors. The parallel between incubation temperature and intrauterine position in laboratory mammals is discussed. PMID:8047573

  7. Incubation temperature modulates post-hatching thermoregulatory behavior in the Madagascar ground gecko, Paroedura pictus.

    PubMed

    Blumberg, Mark S; Lewis, Sean J; Sokoloff, Greta

    2002-09-01

    All vertebrates regulate body temperature within narrow limits, regardless of their physiological capabilities. When do these limits develop, and can they be modified by manipulations of the developmental thermal environment? We addressed these questions by incubating the eggs of the Madagascar ground gecko, Paroedura pictus, at three temperatures and by assessing thermoregulatory behavior in hatchlings. Thermoregulatory behavior was assessed using a two-choice shuttle paradigm, and skin temperatures were measured non-invasively using infrared thermography. The shuttling behavior of hatchlings was systematically affected by the temperature at which they were incubated, and follow-up tests suggested that this effect persisted for at least three weeks post-hatching. The body temperature data from the shuttling experiment were used to model thermoregulatory behavior in a complex thermal environment; the model predicted systematic effects of incubation temperature on thermal preference. The specificity of the alteration in thermoregulatory behavior by incubation temperature is compelling and provides evidence for powerful pre-hatching influences on a fundamental, life-sustaining behavioral process. PMID:12177143

  8. Insights into Himalayan biogeography from geckos: a molecular phylogeny of Cyrtodactylus (Squamata: Gekkonidae).

    PubMed

    Agarwal, Ishan; Bauer, Aaron M; Jackman, Todd R; Karanth, K Praveen

    2014-11-01

    The India-Asia collision profoundly influenced the climate, topography and biodiversity of Asia, causing the formation of the biodiverse Himalayas. The species-rich gekkonid genus Cyrtodactylus is an ideal clade for exploring the biological impacts of the India-Asia collision, as previous phylogenetic hypotheses suggest basal divergences occurred within the Himalayas and Indo-Burma during the Eocene. To this end, we sampled for Cyrtodactylus across Indian areas of the Himalayas and Indo-Burma Hotspots and used three genes to reconstruct relationships and estimate divergence times. Basal divergences in Cyrtodactylus, Hemidactylus and the Palaearctic naked-toed geckos were simultaneous with or just preceded the start of the India-Asia collision. Diversification within Cyrtodactylus tracks the India-Asia collision and subsequent geological events. A number of geographically concordant clades are resolved within Indo-Burmese Cyrtodactylus. Our study reveals 17 divergent lineages that may represent undescribed species, underscoring the previously undocumented diversity of the region. The importance of rocky habitats for Cyrtodactylus indicates the Indo-Gangetic flood plains and the Garo-Rajmahal Gap are likely to have been important historical barriers for this group. PMID:25108260

  9. Bio-inspired Gecko Micro-surface for Drag Reduction in Turbulent Flows

    NASA Astrophysics Data System (ADS)

    Arenas, Isnardo; Carrasquillo, Kenneth; Araya, Guillermo; Castillo, Luciano; Leonardi, Stefano

    2014-11-01

    Direct Numerical Simulations of a turbulent channel flow with a porous wall inspired from the Gecko lizard were performed at Reynolds number of Reτ = 450 . Two superposed fluids were considered. As initial condition, one fluid fills the microfibrillar surface, the interface with the overlying fluid being flat and corresponding to the crests plane. The code is based on a finite difference scheme with a Runge Kutta and fractional step. The porous wall is modeled with the immersed boundary method, while the dynamic of the interface between the two fluids is solved with a level set method. A parametric study has been performed varying the viscosity ratio between the two fluids. Two cases have been considered, with and without surface tension. Without surface tension the microfibrillar wall acts as a rough wall increasing the drag. However, when the surface tension is large enough to maintain the interface stable, the external fluid cannot enter into the porous wall and an effective slip is produced. When the fluid in the porous wall has a viscosity 100 times smaller than that of the overlying fluid, a drag reduction of about 60 % can be observed. In this case, the near wall coherent structures become significantly weaker. The numerical simulations were performed on XSEDE TACC under Grant No. CTS070066. S.L., I.A. and K.C. were supported by ONR MURI grant.

  10. Tooth development in a model reptile: functional and null generation teeth in the gecko Paroedura picta

    PubMed Central

    Zahradnicek, Oldrich; Horacek, Ivan; Tucker, Abigail S

    2012-01-01

    This paper describes tooth development in a basal squamate, Paroedura picta. Due to its reproductive strategy, mode of development and position within the reptiles, this gecko represents an excellent model organism for the study of reptile development. Here we document the dental pattern and development of non-functional (null generation) and functional generations of teeth during embryonic development. Tooth development is followed from initiation to cytodifferentiation and ankylosis, as the tooth germs develop from bud, through cap to bell stages. The fate of the single generation of non-functional (null generation) teeth is shown to be variable, with some teeth being expelled from the oral cavity, while others are incorporated into the functional bone and teeth, or are absorbed. Fate appears to depend on the initiation site within the oral cavity, with the first null generation teeth forming before formation of the dental lamina. We show evidence for a stratum intermedium layer in the enamel epithelium of functional teeth and show that the bicuspid shape of the teeth is created by asymmetrical deposition of enamel, and not by folding of the inner dental epithelium as observed in mammals. PMID:22780101

  11. Mechanism of apoptosis induction in human hepatocellular carcinoma cells following treatment with a gecko peptides mixture

    PubMed Central

    JIN, YING; DUAN, LENG-XIN; XU, XIN-LI; GE, WEN-JING; LI, RUI-FANG; QIU, XIANG-JUN; SONG, YING; CAO, SHAN-SHAN; WANG, JIAN-GANG

    2016-01-01

    The aim of the present study was to investigate the apoptotic effect and molecular mechanisms of gecko peptides mixture (GPM) on the human liver carcinoma HepG2 cell line in vitro. The methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay was performed to identify the dose- (0.10, 0.15, 0.20, 0.25 and 0.30 mg/ml) and time-dependent (24, 48 and 72 h) inhibitory effect of GPM on HepG2 cells and their proliferation. Hoechst 33258 staining was carried out to detect the nuclear change coupled with apoptosis induced by GPM. Western blotting was used to evaluate apoptosis-related protein expression changes induced by GPM, including caspase, cytochrome c (Cyt c) and apoptosis-inducing factor (AIF). MTT results showed that GPM significantly inhibited the proliferation of HepG2 cells in a dose- and time-dependent manner. Hoechst 33258 staining demonstrated that GPM induced typical apoptotic morphological changes, while western blotting analysis revealed that GPM increased caspase-3, caspase-9, Cyt c and AIF protein expression levels in HepG2 cells treated with 0.06 or 0.08 mg/ml for 24 h. In conclusion, GPM could induce apoptosis by activating the intrinsic mitochondrial apoptotic pathways. PMID:27330750

  12. Karyotype Reorganization in the Hokou Gecko (Gekko hokouensis, Gekkonidae): The Process of Microchromosome Disappearance in Gekkota

    PubMed Central

    Srikulnath, Kornsorn; Uno, Yoshinobu; Nishida, Chizuko; Ota, Hidetoshi; Matsuda, Yoichi

    2015-01-01

    The Hokou gecko (Gekko hokouensis: Gekkonidae, Gekkota, Squamata) has the chromosome number 2n = 38, with no microchromosomes. For molecular cytogenetic characterization of the gekkotan karyotype, we constructed a cytogenetic map for G. hokouensis, which retains the ancestral karyotype of Gekkota, with 86 functional genes, and compared it with cytogenetic maps for four Toxicofera species that have many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) and that for a lacertid species (Lacerta agilis) with only one pair of autosomal microchromosomes. Ten pairs of G. hokouensis chromosomes [GHO1, 2, 3, Z(4), 6, 7, 8, 13, 14, and 15] showed highly conserved linkage homology with macrochromosomes and/or macrochromosome arms of the four Toxicofera species and corresponded to eight L. agilis macrochromosomes (LAG). However, GHO5, GHO9, GHO10, GHO11, and LAG6 were composed of chromosome segments that have a homology with Toxicofera microchromosomes, and no homology was found in the chromosomes between G. hokouensis and L. agilis. These results suggest that repeated fusions of microchromosomes may have occurred independently in each lineage of Gekkota and Lacertidae, leading to the disappearance of microchromosomes and appearance of small-sized macrochromosomes. PMID:26241471

  13. Removable partial overdentures with mechanical (precision) attachments.

    PubMed

    Mensor, M C

    1990-10-01

    Mechanical attachments for overdentures have been available in various forms for over a century. The explosive interest in osseointegration and the effort on the part of the profession to avoid the complete denture as a treatment modality has stirred the interest in positive retentive elements for overdentures represented by the mechanical stud and bar attachments. The cited references provide a resource as a trouble-free guide in the selection and use of the various stud and bar attachment systems. The clinical examples show a pattern of application not generally discussed by the manufacturers, illustrating the simplicity of use with the options for all attachments including magnets. The discussion on magnets comes from 9 years of clinical experience. Rare earth magnets provide excellent adjunct retention, and their assembly follows the same protocol and complexity as stud attachment systems. All magnets, at the present state of the art, have a corrosion potential with the exception of the Laser Sealed Units (Golden Dental, Golden, CO). Finally, the mechanics of the attachment overdenture serves as an excellent training field for the osseointegrated prosthesis, be it the classic Brånemark (Nobelpharma USA, Chicago, IL) restorative or the implant overdenture concept. PMID:2227040

  14. Anti-angiogenic activity of gecko aqueous extracts and its macromolecular components in CAM and HUVE-12 cells.

    PubMed

    Tang, Zhen; Huang, Shu-Qiong; Liu, Jian-Ting; Jiang, Gui-Xiang; Wang, Chun-Mei

    2015-01-01

    Gecko is a kind of traditional Chinese medicine with remarkable antineoplastic activity. However, undefined mechanisms and ambiguity regarding active ingredients limit new drug development from gecko. This study was conducted to assess anti-angiogenic properties of the aqueous extracts of fresh gecko (AG) or macromolecular components separated from AG (M-AG). An enzyme-linked immunosorbent assay (ELISA) approach was applied to detect the vascular endothelial growth factor (VEGF) secretion of the tumor cells treated with AG or M-AG. The effect of AG or M-AG on vascular endothelial cell proliferation and migratory ability was analyzed by tetrazolium dye colorimetric method, transwell and wound-healing assays. Chick embryo chorioallantoic membrane (CAM) assays were used to ensure the anti-angiogenic activity of M-AG in vivo. The results showed that AG or M-AG inhibited the VEGF secretion of tumor cells, the relative inhibition rates of AG and M-AG being 27.2% and 53.2% respectively at a concentration of 20 μL/mL. AG and M-AG inhibited the vascular endothelial (VE) cell proliferation with IC50 values of 11.5 ± 0.5 μL/mL and 12.9 ± 0.4 μL/mL respectively. The VE cell migration potential was inhibited significantly (p<0.01) by the AG (≥ 24 μL/mL) or M-AG (≥ 12 μL/ mL) treatment. In vivo, neovascularization of CAM treated with M-AG was inhibited significantly (p<0.05) at a concentration of 0.4 μL/mL. This study provided evidence that anti-angiogenesis is one of the anti-tumor mechanisms of AG and M-AG, with the latter as a promising active component. PMID:25773854

  15. Attachment Behaviors in Autistic Children.

    ERIC Educational Resources Information Center

    Sigman, Marian; Ungerer, Judy A.

    1984-01-01

    Observation of 14 autistic and 14 nonautistic children of equivalent mental age revealed that autistic Ss showed evidence of attachment to their mothers. Among autistic Ss, those showing increased attachment behaviors in response to separation and reunion demonstrated more advanced symbolic play skills than those showing no attachment change.…

  16. Flared tube attachment fitting

    NASA Technical Reports Server (NTRS)

    Alkire, I. D.; King, J. P., Jr.

    1980-01-01

    Tubes can be flared first, then attached to valves and other flow line components, with new fitting that can be disassembled and reused. Installed fitting can be disassembled so parts can be inspected. It can be salvaged and reused without damaging flared tube; tube can be coated, tempered, or otherwise treated after it has been flared, rather than before, as was previously required. Fitting consists of threaded male portion with conical seating surface, hexagonal nut with hole larger than other diameter of flared end of tube, and split ferrule.

  17. Emotion regulation: influences of attachment relationships.

    PubMed

    Cassidy, J

    1994-01-01

    Emotion regulation and quality of attachment are closely linked. It has been proposed here that one influence on individual differences in emotion regulation may be a child's attachment history. Individuals characterized by the flexible ability to accept and integrate both positive and negative emotions are generally securely attached; on the other hand, individuals characterized by either limited or heightened negative affect are more likely to be insecurely attached. While acknowledging the role of infant temperament, I have focused on the role of social factors in examining the link between emotion regulation and attachment. The approach to emotion regulation taken here--that emotion regulation is adaptive in helping a child attain her goals--is esentially a functionalist approach (Bretherton et al., 1986; Campos et al., 1983), consistent with earlier views of emotions as important regulators of interpersonal relationships (Charlesworth, 1982; Izard, 1977). It has been proposed that patterns of emotion regulation serve an important function for the infant: the function of maintaining the relationship with the attachment figure. Emotion regulation has been described as serving this function in two ways. First, the function of maintaining the relationship is thought to be served when infant emotion regulation contributes to the infant's more generalized regulation of the attachment system in response to experiences with the caregiver. Infants who have experienced rejection (insecure/avoidant infants) are thought to minimize negative affect in order to avoid the risk of further rejection. Infants whose mothers have been relatively unavailable or inconsistently available (insecure/ambivalent infants) are thought to maximize negative affect in order to increase the likelihood of gaining the attention of a frequently unavailable caregiver. Both these patterns of emotion regulation help ensure that the child will remain close to the parent and thereby be protected

  18. Retention profiles of stud-type precision attachments.

    PubMed

    Leung, T; Preiskel, H W

    1991-01-01

    This study measured the retention profiles of 11 commercially available stud-type attachment systems suitable for use with overdentures. The vertical distance over which resistance to separation existed was recorded and related to the configuration of the attachments. In many of the systems tested, only a small portion of the vertical length of the attachment contributed to the retention of the unit. PMID:1781881

  19. Ecophysiology Tracks Phylogeny and Meets Ecological Models in an Iberian Gecko.

    PubMed

    Rato, C; Carretero, M A

    2015-01-01

    Because fitness of ectotherms, including reptiles, is highly dependent on temperature and water availability, the study of ecophysiological traits, such as preferred temperature (T p) and water loss rates (WLRs), may provide mechanistic evidence on the restricting factors to the species ranges. The Moorish gecko, Tarentola mauritanica, is a species complex with a circum-Mediterranean distribution. In the Iberian Peninsula, two sister parapatric forms of the complex, known as the Iberian and the European clades, are found. Ecological models previously performed using presence records and bioclimatic variables suggest niche divergence between both lineages correlated with precipitation rather than with temperature. In this study, we test this correlative hypothesis using ecophysiological evidence. In the laboratory, we analyzed the T p and WLRs for 84 adult males from seven distinct populations ascribed to one of the two lineages present in Iberia. Specifically, we evaluated the existence of trait conservatism versus adaptation among populations, lineages, or both. In addition, we tested for a trade-off between water and thermal traits and assessed whether climate regime of sampling localities had any influence on the ecophysiological patterns found. We found that T p is quite conserved at both the population and lineage levels and independent from body size. In contrast, water loss experiments revealed some variation among populations, but the regression analysis failed to detect correlation between T p and WLR at any level. Overall, the European lineage displayed a trend for higher water loss and was more diverse among populations when compared with the Iberian lineage. The lack of correspondence between ecophysiological traits and local climatic conditions favors phylogenetic signal versus adaptation. This suggests divergent evolutionary responses to the environment, mainly acting on water ecology, in both lineages, which may account for the differences in their

  20. Phylogeny of bent-toed geckos (Cyrtodactylus) reveals a west to east pattern of diversification.

    PubMed

    Wood, Perry L; Heinicke, Matthew P; Jackman, Todd R; Bauer, Aaron M

    2012-12-01

    The Asian/Pacific genus Cyrtodactylus is the most diverse and among the most widely distributed genera of geckos, and more species are continually being discovered. Major patterns in the evolutionary history of Cyrtodactylus have remained largely unknown because no published study has broadly sampled across the geographic range and morphological diversity of the genus. We assembled a data set including sequences from one mitochondrial and three nuclear loci for 68 Cyrtodactylus and 20 other gekkotan species to infer phylogenetic relationships within the genus and identify major biogeographic patterns. Our results indicate that Cyrtodactylus is monophyletic, but only if the Indian/Sri Lankan species sometimes recognized as Geckoella are included. Basal divergences divide Cyrtodactylus into three well-supported groups: the single species C. tibetanus, a clade of Myanmar/southern Himalayan species, and a large clade including all other Cyrtodactylus plus Geckoella. Within the largest major clade are several well-supported subclades, with separate subclades being most diverse in Thailand, Eastern Indochina, the Sunda region, the Papuan region, and the Philippines, respectively. The phylogenetic results, along with molecular clock and ancestral area analyses, show Cyrtodactylus to have originated in the circum-Himalayan region just after the Cretaceous/Paleogene boundary, with a generally west to east pattern of colonization and diversification progressing through the Cenozoic. Wallacean species are derived from within a Sundaland radiation, the Philippines were colonized from Borneo, and Australia was colonized twice, once via New Guinea and once via the Lesser Sundas. Overall, these results are consistent with past suggestions of a Palearctic origin for Cyrtodactylus, and highlight the key role of geography in diversification of the genus. PMID:22982633

  1. A description of Haemogregarina species naturally infecting white-spotted gecko (Tarentola annularis) in Qena, Egypt.

    PubMed

    Rabie, Soheir A H; Hussein, Abdel-Nasser A

    2014-08-01

    The present study describes the developmental stages of Haemogregarina species in the blood and tissues of naturally infecting white-spotted gecko Tarentola annularis collected from Qena, Egypt. Different parasite's forms were observed infecting the erythrocytes. The gamonts enclosed within parasitophorous vacuole and seems to have no clear effect on the host cell especially in case of immature parasite forms. But in the presence of mature gamonts the host cell nucleus displaced. The parasitaemia level is up to 280 per 10,000 erythrocytes counted. Trophozoites and gamonts have been recognized in the blood smears. The rounded trophozoite diameter is 3.84 ±0.87 μm, while the elongated trophozoite measured 4.42 ± 0.69 x 2.8 ± 0.56 μm. The mature gamonts were differentiated into two forms; short gamont measuring 10.82 ± 0.82 x 3.30 ± 0.73 μm (range: 10-12.1 x 2.2-4.4 μm) and the long gamont measured 14.67 ± 0.83 x 3.96 ± 0.77 μm (range: 14.1-16.5 x 3.3-5.5 μm). Merogony carried out only in the endothelial cells of the blood capillaries in the lung. Different merogonic stages have been recognized and differentiated in two forms; micromeront measured 13.25 ± 0.50 x 12 ± 0.0 μm and produces a few number of large merozoites, macromeront measured 19.75+0.87x13.25+0.50 im and produces more small sized merozoites. The gamonts and merozoites have the general characteristic ultrastructures of the Apicomplexa containing components of the apical complex, e.g. pellicle, micronemes, rhoptries, and few dense bodies and subpellicular microtubules. PMID:25597149

  2. Landscape Genetics of Leaf-Toed Geckos in the Tropical Dry Forest of Northern Mexico

    PubMed Central

    Blair, Christopher; Jiménez Arcos, Victor H.; Mendez de la Cruz, Fausto R.; Murphy, Robert W.

    2013-01-01

    Habitat fragmentation due to both natural and anthropogenic forces continues to threaten the evolution and maintenance of biological diversity. This is of particular concern in tropical regions that are experiencing elevated rates of habitat loss. Although less well-studied than tropical rain forests, tropical dry forests (TDF) contain an enormous diversity of species and continue to be threatened by anthropogenic activities including grazing and agriculture. However, little is known about the processes that shape genetic connectivity in species inhabiting TDF ecosystems. We adopt a landscape genetic approach to understanding functional connectivity for leaf-toed geckos (Phyllodactylus tuberculosus) at multiple sites near the northernmost limit of this ecosystem at Alamos, Sonora, Mexico. Traditional analyses of population genetics are combined with multivariate GIS-based landscape analyses to test hypotheses on the potential drivers of spatial genetic variation. Moderate levels of within-population diversity and substantial levels of population differentiation are revealed by FST and Dest. Analyses using structure suggest the occurrence of from 2 to 9 genetic clusters depending on the model used. Landscape genetic analysis suggests that forest cover, stream connectivity, undisturbed habitat, slope, and minimum temperature of the coldest period explain more genetic variation than do simple Euclidean distances. Additional landscape genetic studies throughout TDF habitat are required to understand species-specific responses to landscape and climate change and to identify common drivers. We urge researchers interested in using multivariate distance methods to test for, and report, significant correlations among predictor matrices that can impact results, particularly when adopting least-cost path approaches. Further investigation into the use of information theoretic approaches for model selection is also warranted. PMID:23451230

  3. High Risks of Losing Genetic Diversity in an Endemic Mauritian Gecko: Implications for Conservation

    PubMed Central

    Buckland, Steeves; Cole, Nik C.; Groombridge, Jim J.; Küpper, Clemens; Burke, Terry; Dawson, Deborah A.; Gallagher, Laura E.; Harris, Stephen

    2014-01-01

    Genetic structure can be a consequence of recent population fragmentation and isolation, or a remnant of historical localised adaptation. This poses a challenge for conservationists since misinterpreting patterns of genetic structure may lead to inappropriate management. Of 17 species of reptile originally found in Mauritius, only five survive on the main island. One of these, Phelsuma guimbeaui (lowland forest day gecko), is now restricted to 30 small isolated subpopulations following severe forest fragmentation and isolation due to human colonisation. We used 20 microsatellites in ten subpopulations and two mitochondrial DNA (mtDNA) markers in 13 subpopulations to: (i) assess genetic diversity, population structure and genetic differentiation of subpopulations; (ii) estimate effective population sizes and migration rates of subpopulations; and (iii) examine the phylogenetic relationships of haplotypes found in different subpopulations. Microsatellite data revealed significant population structure with high levels of genetic diversity and isolation by distance, substantial genetic differentiation and no migration between most subpopulations. MtDNA, however, showed no evidence of population structure, indicating that there was once a genetically panmictic population. Effective population sizes of ten subpopulations, based on microsatellite markers, were small, ranging from 44 to 167. Simulations suggested that the chance of survival and allelic diversity of some subpopulations will decrease dramatically over the next 50 years if no migration occurs. Our DNA-based evidence reveals an urgent need for a management plan for the conservation of P. guimbeaui. We identified 18 threatened and 12 viable subpopulations and discuss a range of management options that include translocation of threatened subpopulations to retain maximum allelic diversity, and habitat restoration and assisted migration to decrease genetic erosion and inbreeding for the viable subpopulations. PMID

  4. Lateralization in Escape Behaviour at Different Hierarchical Levels in a Gecko: Tarentola angustimentalis from Eastern Canary Islands

    PubMed Central

    García-Muñoz, Enrique; Rato, Catarina; Jorge, Fátima; Carretero, Miguel A.

    2013-01-01

    At the individual level, to be behaviourally lateralized avoids costly duplication of neural circuitry and decreases possible contradictory order from the two brain hemispheres. However, being prey behaviour lateralized at higher hierarchical levels could generate different negative implications, especially if predators are able to make predictions after multiple encounters. These conflicting pressures, namely between the advantages for individuals and the disadvantages for populations could be concealed if higher-level lateralization would arise from the combination of lateralized behaviours of individuals which are mutually dependent. Here, we investigated the lateralization patterns in the escape behaviour of the gecko Tarentola angustimentalis undergoing a predatory attack simulation in a “T” maze experiment. Results showed that gecko populations displayed different degrees of lateralization, with an overall dominance of right-biased individuals. This trend is similar to that observed in the Podarcis wall lizards, which share predators with Tarentola. In addition, different morphological parameters plausible to affect refuge selection were explored in order to link directional asymmetries at morphological level with lateralization during refuge selection. PMID:24260110

  5. Redescription of the rare Philippine false gecko Pseudogekko brevipes (Reptilia: Squamata: Gekkonidae) and description of a new species.

    PubMed

    Davis, Drew R; Watters, Jessa L; Köhler, Gunther; Whitsett, Collin; Huron, Nicholas A; Brown, Rafe M; Diesmos, Arvin C; Siler, Cameron D

    2015-01-01

    Recent investigations into the species diversity of false geckos (genus Pseudogekko Taylor) have revealed several cryptic species, highlighting the need for a more thorough understanding of diversity within this enigmatic genus of endemic Philippine geckos. Newly available genetic data reveal that two of the four currently recognized species are complexes of multiple deeply divergent evolutionary lineages. In this paper we evaluate species diversity in one of these complexes, P. brevipes Boettger, and describe one additional new species. For nearly a century, P. brevipes has been recognized as a single, "widespread" species with a geographic range spanning two major faunal regions and several island groups. Poor understanding of this species has persisted due to both limited sampling and its apparent rarity. We evaluate both morphological and genetic data to define species limits in P. brevipes, and find character-based evidence to justify the recognition of two unique evolutionary lineages, one of which we describe as a new species (P. atiorum sp. nov.). The species included in this study have allopatric distributions and differ from congeners by numerous diagnostic characters of external morphology, and therefore should be recognized as full species in accordance with lineage-based species concepts. This newly described species increases the total number of species of Pseudogekko to seven. PMID:26624104

  6. The regenerated tail of juvenile leopard geckos (Gekkota: Eublepharidae: Eublepharis macularius) preferentially stores more fat than the original.

    PubMed

    Russell, Anthony P; Lynn, Sabrina E; Powell, G Lawrence; Cottle, Andrew

    2015-06-01

    The tail of many species of lizard is used as a site of fat storage, and caudal autotomy is a widespread phenomenon among lizards. This means that caudal fat stores are at risk of being lost if the tail is autotomized. For fat-tailed species, such as the leopard gecko, this may be particularly costly. Previous work has shown that tail regeneration in juveniles of this species is rapid and that it receives priority for energy allocation, even when dietary resources are markedly reduced. We found that the regenerated tails of juvenile leopard geckos are more massive than their original counterparts, regardless of dietary intake, and that they exhibit greater amounts of skeleton, inner fat, muscle and subcutaneous fat than original tails (as assessed through cross-sectional area measurements of positionally equivalent stations along the tail). Autotomy and regeneration result in changes in tail shape, mass and the pattern of tissue distribution within the tail. The regenerated tail exhibits enhanced fat storage capacity, even in the face of a diet that results in significant slowing of body growth. Body growth is thus sacrificed at the expense of rapid tail growth. Fat stores laid down rapidly in the regenerating tail may later be used to fuel body growth or reproductive investment. The regenerated tail thus seems to have adaptive roles of its own, and provides a potential vehicle for studying trade-offs that relate to life history strategy. PMID:25935709

  7. Persistent effect of incubation temperature on stress-induced behavior in the Yucatan banded gecko (Coleonyx elegans).

    PubMed

    Trnik, Marian; Albrechtová, Jana; Kratochvíl, Lukáš

    2011-02-01

    Although variability in behavioral traits within animal populations is well documented, the mechanisms maintaining that variability are still insufficiently known. In this study, we examined whether differences in thermal environment during egg incubation can permanently organize nonsocial behavior across different contexts and situations in a lizard species. We incubated eggs of the Yucatan banded gecko, Coleonyx elegans (Squamata: Gekkota: Eublepharidae) at 3 constant temperatures (26, 28, and 30 °C) and raised juveniles separately under the same conditions until adulthood. We then subjected them to 3 behavioral tests within 2 different contexts: an open-field test and a test of antipredator behavior (stressful context) as well as a test of feeding behavior (nonstressful context). Individuals of both sexes incubated at 30 °C were consistently less active and showed lower frequencies of several stereotypic behaviors in the stressful contexts than did individuals incubated at 26 and 28 °C. The test of feeding behavior revealed no significant effect of incubation temperature on geckos' behavior. Thus, our study demonstrates that developmental plasticity may play an important role in producing variability in stress-induced behavior in lizards. PMID:21244135

  8. Genetic elucidation of cryptic and ancient diversity in a group of Australian diplodactyline geckos: the Diplodactylus vittatus complex.

    PubMed

    Oliver, Paul; Hugall, Andrew; Adams, Mark; Cooper, Steven J B; Hutchinson, Mark

    2007-07-01

    We examine species boundaries and phylogenetic relationships within the Australian diplodactyline geckos currently assigned to Diplodactylus granariensis and Diplodactylus vittatus using data from multiple allozyme loci, the mitochondrial ND2 gene and published karyotypic studies. These analyses uncover at least six morphologically cryptic but genetically distinctive species. The taxa identified correspond poorly with the existing taxonomy and represent a paraphyletic assemblage with respect to a number of other Diplodactylus species included in analyses. Molecular dating indicates that the species identified evolved considerably before the Pleistocene, and that the basal node of the D. vittatus species group (as redefined here) is of comparable age to entire radiations of other Australian squamate families. The antiquity of this one small group within the diplodactyline geckos suggests that further study of patterns of diversification in the diplodactylines will provide both a valuable insight into long-term patterns of environmental change in the Australian continent and a useful contrast for analysis of patterns of radiation in other Australian lizard groups. PMID:17467299

  9. Present diversity of Galápagos leaf-toed geckos (Phyllodactylidae: Phyllodactylus) stems from three independent colonization events.

    PubMed

    Torres-Carvajal, Omar; Rodríguez-Guerra, Andrea; Chaves, Jaime A

    2016-10-01

    We re-examined the biogeography of the leaf-toed geckos (Phyllodactylus) endemic to the Galápagos Islands by analyzing for the first time samples of P. gilberti, a species endemic to Wolf island, in a phylogenetic framework. Our aim was to test the three-colonizations scenario previously proposed for these lizards and estimate the age of each colonization event. To achieve this we estimated simultaneously a species tree and divergence times with Bayesian methods. Our results supported the three-colonizations scenario. Similar to a previous hypothesis, the species tree obtained here showed that most species of Phyllodactylus are nested in a single clade with an age between 5.49 and 13.8Ma, whereas a second independent colonization corresponding to P. darwini from San Cristóbal island occurred 3.03Ma ago. The species from Wolf island, P. gilberti, stems from a more recent colonization event (0.69Ma). Thus, present diversity of Galápagos leaf-toed geckos stems from three independent, asynchronous colonization events. As with other Galápagos organisms, the Pacific coast of South America seems to be the source for the founders of P. gilberti. PMID:27400628

  10. Antimicrobial and Herbal Drug Resistance in Enteric Bacteria Isolated from Faecal Droppings of Common House Lizard/Gecko (Hemidactylus frenatus).

    PubMed

    Singh, Bhoj R; Singh, Vidya; Ebibeni, N; Singh, Raj K

    2013-01-01

    From 194 faecal dropping samples of common house geckos collected from offices (60), houses (88), integrated farm units (IFS,18) and hostels, guest houses, and dining rooms of different canteen/mess (HGM, 28), 326 bacterial isolates of enteric bacteria belonging to 17 genera and 34 species were detected. Escherichia coli were the most frequently (39) isolated followed by Citrobacter freundii (33), Klebsiella pneumonia (27), Salmonella indica (12), Enterobacter gergoviae (12), and Ent. agglomerans (11). Other important bacteria isolated from gecko droppings were Listonella damsela (2), Raoultella terrigena (3), S. salamae (2), S. houtenae (3), Edwardsiella tarda (4), Edwardsiella hoshinae (1), and Klebsiella oxytoca (2). Of the 223 isolates tested for antimicrobial drug sensitivity, 27 (12.1%) had multiple drug resistance (MDR). None of the salmonellae or edwardsiellae had MDR however, MDR strains were significantly more common among Escherichia spp. (P = 1.9 × 10(-5)) and isolates from IFS units (P = 3.58 × 10(-23)). The most effective herbal drug, Ageratum conyzoides extract, inhibited growth of only 27.8% of strains tested followed by ethanolic extract of Zanthoxylum rhetsa (13.9%), eucalyptus oil (5.4%), patchouli oil (5.4%), lemongrass oil (3.6%), and sandalwood oil (3.1%), and Artemisia vulgaris essential oil (3.1%). PMID:24223595

  11. Antimicrobial and Herbal Drug Resistance in Enteric Bacteria Isolated from Faecal Droppings of Common House Lizard/Gecko (Hemidactylus frenatus)

    PubMed Central

    Singh, Bhoj R.; Singh, Vidya; Ebibeni, N.; Singh, Raj K.

    2013-01-01

    From 194 faecal dropping samples of common house geckos collected from offices (60), houses (88), integrated farm units (IFS,18) and hostels, guest houses, and dining rooms of different canteen/mess (HGM, 28), 326 bacterial isolates of enteric bacteria belonging to 17 genera and 34 species were detected. Escherichia coli were the most frequently (39) isolated followed by Citrobacter freundii (33), Klebsiella pneumonia (27), Salmonella indica (12), Enterobacter gergoviae (12), and Ent. agglomerans (11). Other important bacteria isolated from gecko droppings were Listonella damsela (2), Raoultella terrigena (3), S. salamae (2), S. houtenae (3), Edwardsiella tarda (4), Edwardsiella hoshinae (1), and Klebsiella oxytoca (2). Of the 223 isolates tested for antimicrobial drug sensitivity, 27 (12.1%) had multiple drug resistance (MDR). None of the salmonellae or edwardsiellae had MDR however, MDR strains were significantly more common among Escherichia spp. (P = 1.9 × 10−5) and isolates from IFS units (P = 3.58 × 10−23). The most effective herbal drug, Ageratum conyzoides extract, inhibited growth of only 27.8% of strains tested followed by ethanolic extract of Zanthoxylum rhetsa (13.9%), eucalyptus oil (5.4%), patchouli oil (5.4%), lemongrass oil (3.6%), and sandalwood oil (3.1%), and Artemisia vulgaris essential oil (3.1%). PMID:24223595

  12. Sexuality examined through the lens of attachment theory: attachment, caregiving, and sexual satisfaction.

    PubMed

    Péloquin, Katherine; Brassard, Audrey; Lafontaine, Marie-France; Shaver, Phillip R

    2014-01-01

    Attachment researchers have proposed that the attachment, caregiving, and sexual behavioral systems are interrelated in adult love relationships (Mikulincer & Shaver, 2007 ). This study examined whether aspects of partners' caregiving (proximity, sensitivity, control, compulsive caregiving) mediated the association between their attachment insecurities (anxiety and avoidance) and each other's sexual satisfaction in two samples of committed couples (Study 1: 126 cohabiting or married couples from the general community; Study 2: 55 clinically distressed couples). Partners completed the Experiences in Close Relationships measure (Brennan, Clark, & Shaver, 1998 ), the Caregiving Questionnaire (Kunce & Shaver, 1994 ), and the Global Measure of Sexual Satisfaction (Lawrance & Byers, 1998 ). Path analyses based on the actor-partner interdependence model (APIM) revealed that caregiving proximity mediated the association between low attachment avoidance and partners' sexual satisfaction in distressed and nondistressed couples. Sensitivity mediated this association in nondistressed couples only. Control mediated the association between men's insecurities (attachment-related avoidance and anxiety) and their partners' low sexual satisfaction in nondistressed couples. Attachment anxiety predicted compulsive caregiving, but this caregiving dimension was not a significant mediator. These results are discussed in light of attachment theory and their implications for treating distressed couples. PMID:23659357

  13. Scaling and biomechanics of surface attachment in climbing animals

    PubMed Central

    Labonte, David; Federle, Walter

    2015-01-01

    Attachment devices are essential adaptations for climbing animals and valuable models for synthetic adhesives. A major unresolved question for both natural and bioinspired attachment systems is how attachment performance depends on size. Here, we discuss how contact geometry and mode of detachment influence the scaling of attachment forces for claws and adhesive pads, and how allometric data on biological systems can yield insights into their mechanism of attachment. Larger animals are expected to attach less well to surfaces, due to their smaller surface-to-volume ratio, and because it becomes increasingly difficult to distribute load uniformly across large contact areas. In order to compensate for this decrease of weight-specific adhesion, large animals could evolve overproportionally large pads, or adaptations that increase attachment efficiency (adhesion or friction per unit contact area). Available data suggest that attachment pad area scales close to isometry within clades, but pad efficiency in some animals increases with size so that attachment performance is approximately size-independent. The mechanisms underlying this biologically important variation in pad efficiency are still unclear. We suggest that switching between stress concentration (easy detachment) and uniform load distribution (strong attachment) via shear forces is one of the key mechanisms enabling the dynamic control of adhesion during locomotion. PMID:25533088

  14. Scaling and biomechanics of surface attachment in climbing animals.

    PubMed

    Labonte, David; Federle, Walter

    2015-02-01

    Attachment devices are essential adaptations for climbing animals and valuable models for synthetic adhesives. A major unresolved question for both natural and bioinspired attachment systems is how attachment performance depends on size. Here, we discuss how contact geometry and mode of detachment influence the scaling of attachment forces for claws and adhesive pads, and how allometric data on biological systems can yield insights into their mechanism of attachment. Larger animals are expected to attach less well to surfaces, due to their smaller surface-to-volume ratio, and because it becomes increasingly difficult to distribute load uniformly across large contact areas. In order to compensate for this decrease of weight-specific adhesion, large animals could evolve overproportionally large pads, or adaptations that increase attachment efficiency (adhesion or friction per unit contact area). Available data suggest that attachment pad area scales close to isometry within clades, but pad efficiency in some animals increases with size so that attachment performance is approximately size-independent. The mechanisms underlying this biologically important variation in pad efficiency are still unclear. We suggest that switching between stress concentration (easy detachment) and uniform load distribution (strong attachment) via shear forces is one of the key mechanisms enabling the dynamic control of adhesion during locomotion. PMID:25533088

  15. Sentence-Level Attachment Prediction

    NASA Astrophysics Data System (ADS)

    Albakour, M.-Dyaa; Kruschwitz, Udo; Lucas, Simon

    Attachment prediction is the task of automatically identifying email messages that should contain an attachment. This can be useful to tackle the problem of sending out emails but forgetting to include the relevant attachment (something that happens all too often). A common Information Retrieval (IR) approach in analyzing documents such as emails is to treat the entire document as a bag of words. Here we propose a finer-grained analysis to address the problem. We aim at identifying individual sentences within an email that refer to an attachment. If we detect any such sentence, we predict that the email should have an attachment. Using part of the Enron corpus for evaluation we find that our finer-grained approach outperforms previously reported document-level attachment prediction in similar evaluation settings.

  16. The Neurobiology of Attachment to Nurturing and Abusive Caregivers.

    PubMed

    Sullivan, Regina M

    2012-08-01

    Decades of research have shown that childhood experiences interact with our genetics to change the structure and function of the brain. Within the range of normal experiences, this system enables the brain to be modified during development to adapt to various environments and cultures. Experiences with and attachment to the caregiver appear particularly important, and recent research suggests this may be due, in part, to the attachment circuitry within the brain. Children have brain circuitry to ensure attachment to their caregivers. Attachment depends on the offspring learning about the caregiver in a process that begins prenatally and continues through most of early life. This attachment serves two basic functions. First, attachment ensures the infant remain in the proximity of the caregiver to procure resources for survival and protection. Second, attachment "quality programs" the brain. This programming impacts immediate behaviors, as well as behaviors that emerge later in development. Animal research has uncovered segments of the attachment circuitry within the brain and has highlighted rapid, robust learning to support this attachment. A child attaches to the caregiver regardless of the quality of care received, even if the caregiver is abusive and neglectful. While a neural system that ensures attachment regardless of the quality of care has immediate benefits, this attachment comes with a high cost. Traumatic experiences interact with genetics to change the structure and function of the brain, compromising emotional and cognitive development and initiating a pathway to pathology. Neurobiological research on animals suggests that trauma during attachment is processed differently by the brain, with maternal presence dramatically attenuating the fear center of the brain (amygdala). Thus, the immaturity of the brain combined with the unique processing of trauma may underlie the enduring effects of abuse, which remain largely hidden in early life but emerge as

  17. Overview for Attached Payload Accommodations and Environments

    NASA Technical Reports Server (NTRS)

    Schaffer, Craig; Cook, Gene; Nabizadeh, Rodney; Phillion, James

    2007-01-01

    External payload accommodations are provided at attach sites on the U.S provided ELC, U.S. Truss, the Japanese Experiment Module Exposed Facility (JEM EF) and the Columbus EPF (External Payload Facilities). The Integrated Truss Segment (ITS) provides the backbone structure for the ISS. It attaches the solar and thermal control arrays to the rest of the complex, and houses cable distribution trays Extravehicular Activity (EVA) support equipment such as handholds and lighting; and providing for Extravehicular Robotic (EVR) accommodations using the Mobile Servicing System (MSS). It also provides logistics and maintenance, and payload attachment sites. The attachment sites accommodate logistics and maintenance and payloads carriers, zenith and nadir. The JEM-EF, a back porch-like attachment to the JEM Pressurized Module, accommodates up to eight payloads, which can be serviced by the crew via the JEM PM's airlock and dedicated robotic arm. The Columbus-EPF is another porch-like platform that can accommodate two zenith and two nadir looking payloads.

  18. Contact behaviour of setal tips in the hairy attachment system of the fly Calliphora vicina (Diptera, Calliphoridae): a cryo-SEM approach.

    PubMed

    Gorb, Stanislav N; Schuppert, Jan; Walther, Paul; Schwarz, Heinz

    2012-06-01

    The fly Calliphora vicina (Diptera, Calliphoridae) bears attachment pads (pulvilli) covered with setae on their ventral sides. These structures enable attachment to smooth vertical surfaces and ceilings. The contact between the terminal setal tips (spatulae) and various substrates was visualised using various experimental techniques combined with conventional scanning electron microscopy (SEM) and cryo-SEM. The results show that the setal endplates are highly flexible structures that form contact with the surface by bending their tips in the distal direction. With conventional SEM, a comparison of partly attached endplates with unattached endplates demonstrated the presence of a distinct marginal bulge. As observed with cryo-SEM, the bulge continuously disappeared as a larger area of the endplate came into contact. Two explanations of this result are suggested. First, the volume between the bulge, the mid-part of the endplate and the substrate may be filled with a fluid secretion that is released into the contact area in the endplate region. Second, the flexible central part of the endplate may jump into contact with the substrate during contact formation. PMID:22554589

  19. Nanovalve Activation by Surface-Attached Photoacids

    PubMed Central

    Guardado-Alvarez, T. M.; Russell, M. M.

    2015-01-01

    Proton transfer caused by excitation of a photoacid attached to the surface of a mesoporous silica nanoparticle activates a nanovalve and causes release of trapped molecules. The protonation of an aniline- based stalk releases a noncovalently bound cyclodextrin molecule that blocked a pore. The results show that pH-responsive molecular delivery systems can be externally controlled using light. PMID:24942753

  20. Ecomorphology of parasite attachment: experiments with feather lice.

    PubMed

    Bush, Sarah E; Sohn, Edward; Clayton, Dale H

    2006-02-01

    The host specificity of some parasites can be reinforced by morphological specialization for attachment to mobile hosts. For example, ectoparasites with adaptations for attaching to hosts of a particular size might not be able to remain attached to larger or smaller hosts. This hypothesis is suggested by the positive correlation documented between the body sizes of many parasites and their hosts. We adopted an ecomorphological approach to test the attachment hypothesis. We tested the ability of host-specific feather lice (Phthiraptera: Ischnocera) to attach to 6 novel species of pigeons and doves that vary in size by nearly 2 orders of magnitude. Surprisingly, Rock Pigeon lice (Columbicola columbae) remained attached equally well to all 6 novel host species. We tested the relative importance of 3 factors that could facilitate louse attachment: whole-body insertion, tarsal claw use, and mandible use. Insertion, per se, was not necessary for attachment. However, insertion on coarse feathers of large hosts allowed lice to access feather barbules with their mandibles. Mandible use was a key component of attachment regardless of feather size. Attachment constraints do not appear to reinforce host specificity in this system. PMID:16629310

  1. Protein Attachment on Nanodiamonds.

    PubMed

    Lin, Chung-Lun; Lin, Cheng-Huang; Chang, Huan-Cheng; Su, Meng-Chih

    2015-07-16

    A recent advance in nanotechnology is the scale-up production of small and nonaggregated diamond nanoparticles suitable for biological applications. Using detonation nanodiamonds (NDs) with an average diameter of ∼4 nm as the adsorbents, we have studied the static attachment of three proteins (myoglobin, bovine serum albumin, and insulin) onto the nanoparticles by optical spectroscopy, mass spectrometry, and dynamic light scattering, and electrophoretic zeta potential measurements. Results show that the protein surface coverage is predominantly determined by the competition between protein-protein and protein-ND interactions, giving each protein a unique and characteristic structural configuration in its own complex. Specifically, both myoglobin and bovine serum albumin show a Langmuir-type adsorption behavior, forming 1:1 complexes at saturation, whereas insulin folds into a tightly bound multimer before adsorption. The markedly different adsorption patterns appear to be independent of the protein concentration and are closely related to the affinity of the individual proteins for the NDs. The present study provides a fundamental understanding for the use of NDs as a platform for nanomedical drug delivery. PMID:25815400

  2. Dissociative Electron Attachment

    NASA Astrophysics Data System (ADS)

    Arreola, Esmeralda; Esmeralda Arreola Collaboration; Leigh Hargreaves Collaboration

    Since the pioneering work of Boudiaffa et al., it has been understood that electrons, even with energies near or below the ionization threshold, are capable of initiating strand-breaks in human DNA. This discovery raised important questions for cancer treatments, since sub-ionizing electrons are known to be the most copiously produced secondary product of radiation therapy. But even to date these factors are largely excluded from dosimetry calculations. This lack of inclusion is, at least in part, certainly due to the dearth of fundamental data describing low-energy electron interactions with nucleotide molecules that form the basis of DNA. Understanding of how such slow electrons are able to damage DNA remains incomplete, but the strongly peaked nature of Boudiaffa et al.'s data gives strong hints at resonantly driven collision processes. DNA damage is therefore most likely driven by ``dissociative electron attachment'' (DEA). DEA is a rather complicated process to model due to the coupling of electronic and nuclear degrees of freedom in the molecule. At the California State University Fullerton, we are currently commissioning a new spectrometer to study dissociation channels, reaction rates and orientation effects in DEA collisions between slow electrons and nucleotide molecules. At the meeting we will present design parameters and commissioning data for this new apparatus.

  3. Attachment in Preschool Deaf Children.

    ERIC Educational Resources Information Center

    Greenberg, Mark T.

    A study was designed to examine the attachment behavior of 28 preschool deaf children and their hearing mothers and compare their patterns of behavior to previous reports of normal hearing dyads, and within this sample examine the relationship between communicative ability and phase of attachment. The sample was subdivided by communication…

  4. Attachment and Temperament Revisited: Infant Distress, Attachment Disorganization, and the Serotonin Transporter Polymorphism

    PubMed Central

    Brumariu, Laura E.; Bureau, Jean-François; Nemoda, Zsofia; Sasvari-Szekely, Maria; Lyons-Ruth, Karlen

    2015-01-01

    Objective This study's aim was to evaluate whether infant disorganized attachment and infant proneness to distress exhibited differential relations to infant genetic factors as indexed by the serotonin transporter polymorphism. Background The role of the short allele of the serotonin transporter polymorphism (5-HTTLPR) in enhancing sensitivity to fearful and negative affect has been well-established (Canli & Lesch, 2007). In the current study, we used this known property of the short allele to provide a test of an important postulate of attachment theory, namely that infant attachment security or disorganization is not a function of the infant's proneness to distress. Methods Participants were 39 parents and infants assessed between 12 and 18 months in the Strange Situation procedure. Genotype categories for the 5-HTTLPR (and rs25531) were created by both the original and the reclassified grouping system; infant proneness to distress was assessed directly in the Strange Situation Procedure. We also assessed maternal behavior at 18 months to evaluate whether any observed genetic effect indicated a passive effect through the mother. Results Consistent with previous findings, the 5-HTTLPR short allele was significantly related to the infant's wariness and distress, but was not related to attachment security or attachment disorganization. In addition, maternal disrupted interaction with the infant was not related to infant genotype or infant distress. Conclusion Results support the concept that infant proneness to distress is associated with serotonergic factors while infant attachment security or disorganization is not a function of either 5-HTTLPR or behaviorally rated proneness to distress. PMID:26912941

  5. A systems level analysis reveals transcriptomic and proteomic complexity in Ixodes ricinus midgut and salivary glands during early attachment and feeding.

    PubMed

    Schwarz, Alexandra; Tenzer, Stefan; Hackenberg, Michael; Erhart, Jan; Gerhold-Ay, Aslihan; Mazur, Johanna; Kuharev, Jörg; Ribeiro, José M C; Kotsyfakis, Michail

    2014-10-01

    Although pathogens are usually transmitted within the first 24-48 h of attachment of the castor bean tick Ixodes ricinus, little is known about the tick's biological responses at these earliest phases of attachment. Tick midgut and salivary glands are the main tissues involved in tick blood feeding and pathogen transmission but the limited genomic information for I. ricinus delays the application of high-throughput methods to study their physiology. We took advantage of the latest advances in the fields of Next Generation RNA-Sequencing and Label-free Quantitative Proteomics to deliver an unprecedented, quantitative description of the gene expression dynamics in the midgut and salivary glands of this disease vector upon attachment to the vertebrate host. A total of 373 of 1510 identified proteins had higher expression in the salivary glands, but only 110 had correspondingly high transcript levels in the same tissue. Furthermore, there was midgut-specific expression of 217 genes at both the transcriptome and proteome level. Tissue-dependent transcript, but not protein, accumulation was revealed for 552 of 885 genes. Moreover, we discovered the enrichment of tick salivary glands in proteins involved in gene transcription and translation, which agrees with the secretory role of this tissue; this finding also agrees with our finding of lower tick t-RNA representation in the salivary glands when compared with the midgut. The midgut, in turn, is enriched in metabolic components and proteins that support its mechanical integrity in order to accommodate and metabolize the ingested blood. Beyond understanding the physiological events that support hematophagy by arthropod ectoparasites, we discovered more than 1500 proteins located at the interface between ticks, the vertebrate host, and the tick-borne pathogens. Thus, our work significantly improves the knowledge of the genetics underlying the transmission lifecycle of this tick species, which is an essential step for

  6. Predictors of attachment styles of children in foster care: an attachment theory model for working with families.

    PubMed

    McWey, Lenore M

    2004-10-01

    The purpose of this study was to examine the attachment styles of children in foster care and to use this information to inform clinical practice (N = 110). When examining the relationship between attachment style and child characteristics, no significant differences were found. A structural equation model hypothesizing the relation of individual characteristics, losses, and family contact to avoidant attachment was then tested. Results provided tentative support for the hypothesized model. Implications for therapists include being attentive to attachment injuries, and working to create safe therapeutic environments when working with families involved in the foster care system. PMID:15532252

  7. Parenting and preschooler attachment among low-income urban African American families.

    PubMed

    Barnett, D; Kidwell, S L; Leung, K H

    1998-12-01

    This study examined the parental correlates of child attachment in a preschool-aged, economically disadvantaged, urban, African American sample. Sixty-nine 4- to 5-year-olds and their primary caregivers participated in the Strange Situation assessment procedure. Based on Cassidy and Marvin's classification system for preschoolers, 61% of the children were classified as securely attached, with girls being significantly more likely to be securely attached than boys (74% versus 45%). The majority of the insecure attachments were of the avoidant variety. Consistent with attachment theory, parents of securely attached children were rated as significantly more warm and accepting and less controlling with their children than were parents of insecurely attached preschoolers. Relative to parents of securely attached preschoolers, parents of children judged to be insecurely attached reported being more likely to use corporal punishment and less likely to use verbal reminders when their children misbehaved. Parenting was associated with attachment over and above the effects of child sex. PMID:9914645

  8. Effect of variable temperatures, darkness and light on the secretion of melatonin by pineal explants in the gecko, Christinus marmoratus.

    PubMed

    Moyer, R W; Firth, B T; Kennaway, D J

    1997-02-01

    This study examined the combined effect of thermocycles with either variable or constant photic conditions on melatonin production by pineal organs in vitro in the gecko, Christinus marmoratus. A 30 degrees C:15 degrees C thermocycle elicited a rhythm of melatonin production under conditions of 12L:12D, constant light or constant darkness when the cryophase coincided with the dark phase of the photocycle or with the subjective night. A 6 h advance of the thermocycle with respect to the photocycle produced an advance in the onset and offset of melatonin production in subsequent nights. When the thermocycle was 180 degrees out of phase with the photoperiod, the rhythm of melatonin production was disrupted, suggesting a differential pattern of sensitivity to photothermal stimuli. It was concluded that both light and temperature are important modulators of pineal function although their combined effects on pineal melatonin production is complex and unclear. PMID:9045997

  9. New Zealand geckos (Diplodactylidae): Cryptic diversity in a post-Gondwanan lineage with trans-Tasman affinities.

    PubMed

    Nielsen, Stuart V; Bauer, Aaron M; Jackman, Todd R; Hitchmough, Rod A; Daugherty, Charles H

    2011-04-01

    We used a multi-gene approach to assess the phylogenetic relationships of New Zealand diplodactylid geckos to their Australian and New Caledonian relatives and to one another. Data from nuclear (RAG-1, PDC) and mitochondrial (ND2, 16S) genes from >180 specimens representing all 19 recognized New Zealand taxa and all but two of 20 putatively new species suggested by previous studies were analyzed using Maximum Parsimony, Maximum Likelihood and Bayesian inference. All analyses retrieved a monophyletic New Zealand clade, most closely related to the Australian Diplodactylidae exclusive of Pseudothecadactylus. Hoplodactylus is paraphyletic and composed of two morphological groups: a broad-toed clade, consisting of the island-restricted, largest extant species, Hoplodactylus duvaucelii, and the species-rich, wide-ranging Hoplodactylus maculatus clade; and a narrow-toed clade, comprising five monophyletic subgroups: Naultinus, the Hoplodactylus pacificus and Hoplodactylus granulatus clades, and the distinctive species Hoplodactylus rakiurae and Hoplodactylus stephensi. Each of these lineages is here recognized at the generic level. Our data support recognition of 16 new species (36 total), and five new or resurrected genera (seven total). The New Zealand diplodactylid radiation split from its Australian relatives 40.2mya (95% highest posterior density estimate 28.9-53.5), after the opening of the Tasman Sea. Their distribution cannot, therefore, be regarded as derived as a result of Gondwanana vicariance. The age of the New Zealand crown group, 24.4mya (95% highest posterior density estimate 15.5-33.8), encompasses the period of the 'Oligocene drowning' of New Zealand and is consistent with the hypothesis that New Zealand was not completely inundated during this period. Major lineages within New Zealand geckos diverged chiefly during the mid- to late Miocene, probably in association with a suite of geological and climatological factors that have characterized the region

  10. Autonomous berthing/unberthing of a Work Attachment Mechanism/Work Attachment Fixture (WAM/WAF)

    NASA Technical Reports Server (NTRS)

    Nguyen, Charles C.; Antrazi, Sami S.

    1992-01-01

    Discussed here is the autonomous berthing of a Work Attachment Mechanism/Work Attachment Fixture (WAM/WAF) developed by NASA for berthing and docking applications in space. The WAM/WAF system enables fast and reliable berthing (unberthing) of space hardware. A successful operation of the WAM/WAF requires that the WAM motor velocity be precisely controlled. The operating principle and the design of the WAM/WAF is described as well as the development of a control system used to regulate the WAM motor velocity. The results of an experiment in which the WAM/WAF is used to handle an orbital replacement unit are given.

  11. Attachment anxiety is related to Epstein–Barr virus latency

    PubMed Central

    Fagundes, Christopher P.; Jaremka, Lisa M.; Glaser, Ronald; Alfano, Catherine M.; Povoski, Stephen P.; Lipari, Adele M.; Agnese, Doreen M.; Yee, Lisa D.; Carson, William E.; Farrar, William B.; Malarkey, William B.; Chen, Min; Kiecolt-Glaser, Janice K.

    2015-01-01

    Attachment theory provides a framework for understanding individual differences in chronic interpersonal stress. Attachment anxiety, a type of relationship insecurity characterized by worry about rejection and abandonment, is a chronic interpersonal stressor. Stress impacts cellular immunity, including herpes-virus reactivation. We investigated whether attachment anxiety was related to the expression of a latent herpesvirus, Epstein–Barr virus (EBV), when individuals were being tested for breast or colon cancer and approximately 1 year later. Participants (N = 183) completed a standard attachment questionnaire and provided blood to assess EBV viral capsid antigen (VCA) IgG antibody titers. Individuals with more attachment anxiety had higher EBV VCA IgG antibody titers than those with less attachment anxiety. The strength of the association between attachment anxiety and antibody titers was the same at both assessments. This study is the first to show an association between latent herpesvirus reactivation and attachment anxiety. Because elevated herpesvirus antibody titers reflect poorer cellular immune system control over the latent virus, these data suggest that high attachment anxiety is associated with cellular immune dysregulation. PMID:24945717

  12. Universal precision sine bar attachment

    NASA Technical Reports Server (NTRS)

    Mann, Franklin D. (Inventor)

    1989-01-01

    This invention relates to an attachment for a sine bar which can be used to perform measurements during lathe operations or other types of machining operations. The attachment can be used for setting precision angles on vises, dividing heads, rotary tables and angle plates. It can also be used in the inspection of machined parts, when close tolerances are required, and in the layout of precision hardware. The novelty of the invention is believed to reside in a specific versatile sine bar attachment for measuring a variety of angles on a number of different types of equipment.

  13. The Intergenerational Transmission of Attachment Behavior.

    ERIC Educational Resources Information Center

    Clubb, Richard D.; And Others

    This study examines the relationship between parent-child attachment and parental attachment styles. It is hypothesized that: (1) parental attachment styles are transmitted to the infant through parent-child and parent-parent interaction; and (2) parental attachment styles are reflected in parent-child attachment. Some research supports the idea…

  14. Everything You Want To Know about Attachment.

    ERIC Educational Resources Information Center

    Honig, Alice Sterling

    This paper discusses infant attachment, which it defines as a long-lasting emotional bond revealed when a child under stress seeks out and tries to stay close to a specific figure. The paper addresses: (1) What is attachment? Who are the pioneers in attachment theory?; (2) How do we notice attachment in action?; (3) Is attachment the only…

  15. Hiding in plain sight: a new species of bent-toed gecko (Squamata: Gekkonidae: Cyrtodactylus) from West Timor, collected by Malcolm Smith in 1924.

    PubMed

    Kathriner, Andrew; Bauer, Aaron M; O'shea, Mark; Sanchez, Caitlin; Kaiser, Hinrich

    2014-01-01

    We describe a new species of bent-toed gecko from a single specimen initially collected in 1924 by Malcolm Smith on Timor Island in the Lesser Sunda Archipelago of Indonesia. Cyrtodactylus celatus sp. nov. is distinguished from all other congeners by the following combination of characters: small adult size; without spinose tubercles on the ventrolateral body fold and along the lateral margin of the tail; 16 longitudinal rows of tubercles at midbody; 42 ventral scales between the ventrolateral folds at midbody; no transversely enlarged, median subcaudal scales; 17 subdigital lamellae (seven basal + ten distal) under the fourth toe; no abrupt transition between postfemoral and ventral femoral scale series. The specimen is the earliest confirmed record of the genus Cyrtodactylus for Timor, and it is the first putatively endemic gecko species described from this island.  PMID:25543756

  16. Attachment at work and performance.

    PubMed

    Neustadt, Elizabeth A; Chamorro-Premuzic, Tomas; Furnham, Adrian

    2011-09-01

    This paper examines the relations between self-reported attachment orientation at work and personality, self-esteem, trait emotional intelligence (aka emotional self-efficacy), and independently assessed career potential and job performance. Self-report data were collected from 211 managers in an international business in the hospitality industry; independent assessments of these managers' job performance and career potential were separately obtained from the organization. A self-report measure of romantic attachment was adapted for application in the work context; a two-factor solution was found for this measure. Secure/autonomous attachment orientation at work was positively related to self-esteem, trait emotional intelligence, extraversion, agreeableness, and conscientiousness, and also to job performance. Not only was secure/autonomous attachment orientation at work statistically predictive of job performance, but the new measure also made a distinct contribution, beyond conscientiousness, to this prediction. PMID:21838647

  17. Adult attachment and declining birthrates.

    PubMed

    Draper, Thomas W; Holman, Thomas B; White, Whitney; Grandy, Shannon

    2007-02-01

    Attachment scores for 658 young adults living in the U.S.A. were obtained using the Experiences in Close Relationships scale. The participants came from a subsample of the RELATE data set, who had also filled out the adult attachment measure. Those young adults living in Utah County, Utah, an area of the country with a higher than normal birthrate (88% members of the Church of Jesus Christ of Latter-day Saints), also had higher than average adult attachment scores. While the methodology was not sufficient to assess causal direction nor eliminate the possibility of unidentified influences, an undiscussed psychological factor, adult attachment, may play a role in the numerical declines observed among nonimmigrant communities in the USA and Europe. PMID:17450996

  18. Salmonella Isolates in the Introduced Asian House Gecko (Hemidactylus frenatus) with Emphasis on Salmonella Weltevreden, in Two Regions in Costa Rica.

    PubMed

    Jiménez, Randall R; Barquero-Calvo, Elías; Abarca, Juan G; Porras, Laura P

    2015-09-01

    The Asian house gecko Hemidactylus frenatus has been widely introduced in Costa Rica and tends to establish in human settlements. Some studies in other invaded countries have suggested that this gecko plays a significant role in the epidemiology of salmonellosis and it is of value to public health. To our knowledge, no studies have examined Salmonella from this species in Costa Rica. Therefore, we collected 115 geckos from houses in two Costa Rican regions. We examined gut contents for Salmonella through microbiological analysis. Presumptive Salmonella spp. were sent to a reference laboratory for serotyping and antimicrobial susceptibility testing. Molecular typing was also conducted with the main Salmonella isolates of zoonotic relevance in Costa Rica. H. frenatus was found in 95% of the houses surveyed. Salmonella was isolated in 4.3% of the samples, and four zoonotic serovars were detected. None of the isolates were resistant to the antibiotics most frequently used for salmonellosis treatment in Costa Rica. All Salmonella isolates from the lower gut of H. frenatus are associated with human salmonellosis. Pulsotypes from Salmonella enterica serotype Weltevreden were identical to the only clone previously reported from human samples in Costa Rica. Molecular typing of Salmonella Weltevreden suggested that H. frenatus harbors a serovar of public health importance in Costa Rica. Results demonstrated that H. frenatus plays a role in the epidemiology of human salmonellosis in two regions of Costa Rica. However, more detailed epidemiological studies are needed to understand better the role of the Asian house gecko with human salmonellosis, especially caused by Salmonella Weltevreden, and to quantify its risk in Costa Rica accurately. PMID:26378974

  19. Development of the Gecko (Pachydactylus turneri) Animal Model during Foton M-2 to Study Comparative Effects of Microgravity in Terrestrial and Aquatic Organisms

    NASA Technical Reports Server (NTRS)

    Almeida, E. A.; Roden, C.; Phillips, J. A.; Globus, R. K.; Searby, N.; Vercoutere, W.; Morey-Holton, E.; Gulimova, V.; Saveliev, S.; Tairbekov, M.; Iwaniec, U. T.; McNamra, A. J.; Turner, R. T.

    2006-01-01

    Terrestrial organisms exposed to microgravity during spaceflight experience degeneration in bone, muscle, and possibly other tissues that require gravity-mediated mechanical stimulation for normal regenerative growth. In the Gecko experiment aboard Foton M-2, we flew for the first time, five terrestrial Pachydactylus turneri specimens to develop a model of microgravity effects comparable to the newt Pleurodeles waltl, a well-established model organism for spaceflight. These lower vertebrate species have similar body plans and size, are poikilothermic, have tissue regenerative ability, and are adapted to moderate periods of fasting. Furthermore the gecko (Pachydactylus) can also survive prolonged periods without water. In pre-flight control experiments and after a 16-day Foton M-2 spaceflight without food or water, the geckos were recovered and showed no apparent negative health effects. However, detailed analysis of bone mass and architecture by micro Computed Tomography { pCT), showed that both synchronous control and spaceflight animals lost significant amounts of cancellous bone in the distal femur and humerus relative to basal controls. In addition, cell cycle analysis of 30h post-flight liver tissue reveals a shift of DNA content from G2 and S to G1, both in spaceflight and synchronous controls. Together, these results suggest that housing conditions alone induce rapid catabolism of cancellous bone and reduced normal tissue regeneration. Further use of the gecko Puchydactylus turneri as a spaceflight model requires modification of housing conditions, possibly by including water and food, or changing other factors such as eliminating housing stresses to obtain stable bone structure and tissue regeneration during spaceflight experiments.

  20. The Attachment and Clinical Issues Questionnaire (ACIQ): scale development.

    PubMed

    Lindberg, Marc A; Thomas, Stuart W

    2011-01-01

    In line with dynamic systems and dialectical theories of development, it was theorized that a psychopathology such as an addiction could have several causes (equifinality) and that more specific diagnoses and treatments of the most salient clinical issues for individuals coming from different developmental paths could increase the success rates of most therapies. Further, the issues from a developmental dynamic systems perspective should include not only individual clinical issues, but also relational, familial, peer, and organizational functioning. The Attachment and Clinical Issues Questionnaire (ACIQ) was developed as a research and clinical instrument relevant to these concerns. The 29 scales were based on naturalistic observations of patients in treatment and 12-step groups, attachment theory, and the clinical literature dealing with the addictions. The attachment scales were taken from classic attachment theory but, in line with more recent formulations, included relations to mother, father, and partner. Study 1 found the ACIQ to have good coefficient alphas (.79), and factor analyses revealed that the eight factors loaded on different attachment figures and sets of clinical issues rather than attachment styles per se. Study 2 found test-retest reliability to be, on average, .79. The results were in line with the developmental hypothesis that partner and father attachments are different than attachments to mother, and that family and peer relations as well as clinical issues need to be considered separately. PMID:22256681

  1. Biliprotein maturation: the chromophore attachment

    PubMed Central

    Scheer, H; Zhao, K-H

    2008-01-01

    Biliproteins are a widespread group of brilliantly coloured photoreceptors characterized by linear tetrapyrrolic chromophores, bilins, which are covalently bound to the apoproteins via relatively stable thioether bonds. Covalent binding stabilizes the chromoproteins and is mandatory for phycobilisome assembly; and, it is also important in biliprotein applications such as fluorescence labelling. Covalent binding has, on the other hand, also considerably hindered biliprotein research because autocatalytic chromophore additions are rare, and information on enzymatic addition by lyases was limited to a single example, an EF-type lyase attaching phycocyanobilin to cysteine-α84 of C-phycocyanin. The discovery of new activities for the latter lyases, and of new types of lyases, have reinvigorated research activities in the subject. So far, work has mainly concentrated on cyanobacterial phycobiliproteins. Methodological advances in the process, however, as well as the finding of often large numbers of homologues, opens new possibilities for research on the subsequent assembly/disassembly of the phycobilisome in cyanobacteria and red algae, on the assembly and organization of the cryptophyte light-harvesting system, on applications in basic research such as protein folding, and on the use of phycobiliproteins for labelling. PMID:18284595

  2. Continuous monitoring of bacterial attachment

    NASA Technical Reports Server (NTRS)

    Koeing, D. W.; Mishra, S. K.; Pierson, D. L.

    1994-01-01

    A major concern with the Space Station Freedom (SSF) water supply system is the control of longterm microbial contamination and biofilm development in the water storage and distribution systems. These biofilms have the potential for harboring pathogens as well as microbial strains containing resistance factors that could negatively influence crew health. The proposed means for disinfecting the water system on SSF (iodine) may encourage the selection of resistant strains. In fact, biofilm bacteria were observed in water lines from the Space Shuttle Columbia (OV-102); therefore, an alternative remediation method is required to disinfect spacecraft water lines. A thorough understanding of colonization events and the physiological parameters that will influence bacteria adhesion is required. The limiting factor for development of this technology is the ability to continuously monitor adhesion events and the effects of biocides on sessile bacteria. Methods were developed to allow bacterial adhesion and subsequent biocidal treatment to be monitored continuously. This technique couples automated image analysis with a continuous flow of a bacterial suspension through an optical flow cell. A strain of Pseudomonas cepacia isolated from the water supply of the Space Shuttle Discovery (OV-103) during STS-39 was grown in a nitrogen-limited continuous culture. This culture was challenged continuously with iodine during growth, and the adhesion characteristics of this strain was measure with regard to flow rate. Various biocides (ozone, hypochlorite, and iodine) were added to the flow stream to evaluate how well each chemical removed the bacteria. After biocide treatment, a fresh bacterial suspension was introduced into the flow cell, and the attachment rate was evaluated on the previously treated surface. This secondary fouling was again treated with biocide to determine the efficacy of multiple batch chemical treatments in removing biofilm.

  3. Effect of attachment strategies on bipartite networks

    NASA Astrophysics Data System (ADS)

    Ganguly, Niloy; Saha, Sudipta; Maiti, Abyayananda; Agarwal, Sanket; Peruani, Fernando; Mukherjee, Animesh

    2013-06-01

    Bipartite systems show remarkable variations in their topological asymptotic properties, e.g., in their degree distribution. Such variations depend on the underlying growth dynamics. A scenario of particular importance is when the two partitions of the bipartite structure do not grow at an equal rate. Here, we focus on the case where one of the partitions can be assumed to be fixed while the other partition grows in time as observed in the codon-gene or alphabet-word network. We show that subtle changes in growth dynamics, particularly in the attachment kernel, can lead to drastic changes of the emergent topological properties. We present a detail analysis of various growth strategies, including sequential and parallel addition of nodes, as well as with and without replacement attachment kernels. Analytical results have been compared with stochastic simulations as well as with real systems showing in all cases an excellent agreement.

  4. 10 CFR 75.15 - Facility attachments.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Accounting and Control for Facilities § 75.15 Facility attachments. (a) The Facility Attachment or... under Article 39(b) of the main text of the Safeguards Agreement, do not have Facility Attachments...

  5. Armored geckos: A histological investigation of osteoderm development in Tarentola (Phyllodactylidae) and Gekko (Gekkonidae) with comments on their regeneration and inferred function.

    PubMed

    Vickaryous, M K; Meldrum, G; Russell, A P

    2015-11-01

    Osteoderms are bone-rich organs found in the dermis of many scleroglossan lizards sensu lato, but are only known for two genera of gekkotans (geckos): Tarentola and Gekko. Here, we investigate their sequence of appearance, mode of development, structural diversity and ability to regenerate following tail loss. Osteoderms were present in all species of Tarentola sampled (Tarentola annularis, T. mauritanica, T. americana, T. crombei, T. chazaliae) as well as Gekko gecko, but not G. smithii. Gekkotan osteoderms first appear within the integument dorsal to the frontal bone or within the supraocular scales. They then manifest as mineralized structures in other positions across the head. In Tarentola and G. gecko, discontinuous clusters subsequently form dorsal to the pelvis/base of the tail, and then dorsal to the pectoral apparatus. Gekkotan osteoderm formation begins once the dermis is fully formed. Early bone deposition appears to involve populations of fibroblast-like cells, which are gradually replaced by more rounded osteoblasts. In T. annularis and T. mauritanica, an additional skeletal tissue is deposited across the superficial surface of the osteoderm. This tissue is vitreous, avascular, cell-poor, lacks intrinsic collagen, and is herein identified as osteodermine. We also report that following tail loss, both T. annularis and T. mauritanica are capable of regenerating osteoderms, including osteodermine, in the regenerated part of the tail. We propose that osteoderms serve roles in defense against combative prey and intraspecific aggression, along with anti-predation functions. PMID:26248595

  6. DPF heater attachment mechanisms

    DOEpatents

    Gonze, Eugene V [Pinckney, MI; Ament, Frank [Troy, MI

    2011-04-26

    An exhaust filter system includes a particulate filter (PF) that is disposed downstream from an engine. The PF filters particulates within an exhaust from the engine. A heating element heats particulate matter in the PF. A fastener limits expansion movement of the heating element relative to the PF.

  7. Attachment and Health-Related Physiological Stress Processes

    PubMed Central

    Pietromonaco, Paula R.; Powers, Sally I.

    2015-01-01

    People who are more securely attached to close partners show health benefits, but the mechanisms underlying this link are not well specified. We focus on physiological pathways that are potential mediators of the connection between attachment in childhood and adulthood and health and disease outcomes. Growing evidence indicates that attachment insecurity (vs. security) is associated with distinctive physiological responses to stress, including responses involving the HPA, SAM and immune systems, but these responses vary with type of stressor (e.g., social/nonsocial) and contextual factors (e.g., partner’s attachment style). Taking this more nuanced perspective will be important for understanding the conditions under which attachment shapes health-related physiological processes as well as downstream health and disease consequences. PMID:25729755

  8. Frequency intermittency and energy pumping by linear attachments

    NASA Astrophysics Data System (ADS)

    Roveri, N.; Carcaterra, A.; Akay, A.

    2014-09-01

    The present paper considers the problem of realizing an effective targeted energy pumping from a linear oscillator to a set of ungrounded linear resonators attached to it. Theoretical as well as numerical results demonstrate the efficacy of using a complex attachment as a passive absorber of broadband energy injected into the primary structure. The paper unveils also the existence of an instantaneous frequency associated with the master response characterized by intermittency: a rather surprising result for a linear autonomous system. Comparison with nonlinear energy sinks demonstrates that the two systems have some analogies in this respect and that the linear complex attachment is a very efficient energy trap.

  9. View of redwood planks attached to the face of Lake ...

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

    View of redwood planks attached to the face of Lake Sabrina Dam, close-up, detail showing overlapping planks at right edge of photo - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  10. Attachment to Caregivers and Type 1 Diabetes in Children

    PubMed Central

    DROBNIČ RADOBULJAC, Maja; SHMUELI-GOETZ, Yael

    2015-01-01

    Attachment is a behavioral and physiological system, which enables individual’s dynamic adaptation to its environment. Attachment develops in close interaction between an infant and his/her mother, plays an important role in the development of the infant’s brain, and influences the quality of interpersonal relationships throughout life. Security of attachment is believed to influence individual response to stress, exposing insecurely organized individuals to deregulated autonomic nervous system and exaggerated hypothalamic-pituitary-adrenal activity, which, in turn, produces increased and prolonged exposure to stress-hormones. Such stress responses may have considerable implications for the development of diverse health-risk conditions, such as insulin resistance and hyperlipidemia, shown by numerous studies. Although the mechanisms are not yet fully understood, there is compelling evidence highlighting the role of psychological stress in the development of type 1 diabetes (T1D). One of the possible contributing factors for the development of T1D may be the influence of attachment security on individual stress reactivity. Thus, the suggestion is that insecurely attached individuals are more prone to experience increased and prolonged influence of stress hormones and other mechanisms causing pancreatic beta-cell destruction. The present paper opens with a short overview of the field of attachment in children, the principal attachment classifications and their historic development, describes the influence of attachment security on individual stress-reactivity and the role of the latter in the development of T1D. Following is a review of recent literature on the attachment in patients with T1D with a conclusion of a proposed role of attachment organization in the etiology of T1D.

  11. A System for a Water Thickness Gauging in a Bellows Tube was Developed, by using a Special UT Probe Attachment and an Immersion Ultrasonic Inspection

    SciTech Connect

    Kil-Mo, Koo; Sang-Baik, Kim; Young-Moo, Cheong; Hwan-Sung, Jung; In-Chul, Lim; Chi-Seong, Park

    2006-07-01

    A thickness gauging for most engineering materials can be measured ultrasonically, including metals, plastics, ceramics, composites, epoxies, and glass, as well as liquid levels and the thickness of certain biological specimens. Precision ultrasonic thickness gauges for liquid levels usually operate at frequencies between 500 KHz and 100 MHZ, by using piezoelectric transducers to generate bursts of sound waves when excited by electrical pulses. In this experiment, a residual water level gauging in a bellow tube is measured by using an immersion ultrasonic technique and a special UT probe attachment. There are two kinds of transducers according to the water thickness. In this case, the enhanced S/N ratio could be obtained from the 15 MHz frequency transducer more than a 2.25 MHz frequency transducer, because of the good resolution of the transducer with a wide band frequency, and we could also obtain the frequency domain from each time domain signal by the FFT function. It is possible to analyze the signal patterns and some information from the frequency domain. (authors)

  12. Bovine Colostrum Contains Immunoglobulin G Antibodies against Intimin, EspA, and EspB and Inhibits Hemolytic Activity Mediated by the Type Three Secretion System of Attaching and Effacing Escherichia coli▿

    PubMed Central

    Vilte, Daniel A.; Larzábal, Mariano; Cataldi, Ángel A.; Mercado, Elsa C.

    2008-01-01

    Enterohemorrhagic Escherichia coli (EHEC) is the main cause of hemolytic-uremic syndrome, an endemic disease in Argentina which had an incidence in 2005 of 13.9 cases per 100,000 children younger than 5 years old. Cattle appear to be a major reservoir of EHEC, and a serological response to EHEC antigens has been demonstrated in natural and experimental infections. In the current study, antibodies against proteins implicated in EHEC's ability to form attaching and effacing lesions, some of which are exported to the host cell via a type three secretion system (TTSS), were identified in bovine colostrum by Western blot analysis. Twenty-seven (77.0%) of the 35 samples examined contained immunoglobulin G (IgG) antibodies against the three proteins assayed in this study: EspA, EspB, and the carboxy-terminal 280 amino acids of γ-intimin, an intimin subtype associated mainly with O157:H7 and O145:H- serotypes. Every colostrum sample was able to inhibit, in a range between 45.9 and 96.7%, the TTSS-mediated hemolytic activity of attaching and effacing E. coli. The inhibitory effect was partially mediated by IgG and lactoferrin. In conclusion, we found that early colostrum from cows contains antibodies, lactoferrin, and other unidentified substances that impair TTSS function in attaching and effacing E. coli strains. Bovine colostrum might act by reducing EHEC colonization in newborn calves and could be used as a prophylactic measure to protect non-breast-fed children against EHEC infection in an area of endemicity. PMID:18562563

  13. Bovine colostrum contains immunoglobulin G antibodies against intimin, EspA, and EspB and inhibits hemolytic activity mediated by the type three secretion system of attaching and effacing Escherichia coli.

    PubMed

    Vilte, Daniel A; Larzábal, Mariano; Cataldi, Angel A; Mercado, Elsa C

    2008-08-01

    Enterohemorrhagic Escherichia coli (EHEC) is the main cause of hemolytic-uremic syndrome, an endemic disease in Argentina which had an incidence in 2005 of 13.9 cases per 100,000 children younger than 5 years old. Cattle appear to be a major reservoir of EHEC, and a serological response to EHEC antigens has been demonstrated in natural and experimental infections. In the current study, antibodies against proteins implicated in EHEC's ability to form attaching and effacing lesions, some of which are exported to the host cell via a type three secretion system (TTSS), were identified in bovine colostrum by Western blot analysis. Twenty-seven (77.0%) of the 35 samples examined contained immunoglobulin G (IgG) antibodies against the three proteins assayed in this study: EspA, EspB, and the carboxy-terminal 280 amino acids of gamma-intimin, an intimin subtype associated mainly with O157:H7 and O145:H- serotypes. Every colostrum sample was able to inhibit, in a range between 45.9 and 96.7%, the TTSS-mediated hemolytic activity of attaching and effacing E. coli. The inhibitory effect was partially mediated by IgG and lactoferrin. In conclusion, we found that early colostrum from cows contains antibodies, lactoferrin, and other unidentified substances that impair TTSS function in attaching and effacing E. coli strains. Bovine colostrum might act by reducing EHEC colonization in newborn calves and could be used as a prophylactic measure to protect non-breast-fed children against EHEC infection in an area of endemicity. PMID:18562563

  14. Pilot study of a program delivered within the regular service system in Germany: effect of a short-term attachment-based intervention on maternal sensitivity in mothers at risk for child abuse and neglect.

    PubMed

    Pillhofer, Melanie; Spangler, Gottfried; Bovenschen, Ina; Kuenster, Anne K; Gabler, Sandra; Fallon, Barbara; Fegert, Joerg M; Ziegenhain, Ute

    2015-04-01

    This pilot study examined the effectiveness of a short-term attachment-based intervention, the Ulm Model, in a German population at risk for child abuse and neglect. The intervention used home visits and video feedback to promote maternal sensitivity, and was implemented by trained staff within the health care and youth welfare systems. Mothers in the control group (n=33) received standard services only, while those in the intervention group (n=63) additionally the Ulm Model intervention. The outcomes measured were maternal sensitivity, as assessed by the CARE-Index at pre-intervention, after the last session, and at about 6 and 12 months of age; and infant socio-emotional development, as assessed by the ET6-6 development test at about 6 and 12 months of age. The moderating effects on treatment outcomes of two variables were examined: risk for child abuse (moderate vs. high) and type of maternal attachment representation (secure vs. insecure). Among participants at moderate risk for child abuse, no differences were found between the intervention group and control group in either maternal sensitivity or infant development. Among those considered high risk, mothers in the intervention group showed a significant increase in maternal sensitivity from pre- to post-intervention; however, no group differences were seen at follow-up. There were some indications that infants of mothers in the intervention group showed better emotional development. The variable of maternal attachment representation was not a significant moderator for the intervention effect, but post hoc analysis indicated that the mean sensitivity of secure mothers was significant higher at the 6-month follow-up. PMID:25066526

  15. Different perspectives on the sex-attachment link: towards an emotion-motivational account.

    PubMed

    Dewitte, Marieke

    2012-01-01

    Although the link between sex and attachment was made decades ago (Hazan & Shaver, 1987), theories on sexual and attachment functioning have been developed in relative isolation. Recent efforts to integrate both literatures have been complicated by the fact that the sex-attachment link has been approached from very different perspectives, including biological, evolutionary, developmental, cognitive, and social psychology approaches. Also, at the empirical level, research on sex and attachment lacks overarching synthesis. This article gives an overview of the most important theoretical ideas and empirical insights on sex and attachment. It starts with describing general models that approach the sex-attachment link from an evolutionary and neurobiological perspective. Then, it summarizes theoretical and empirical ideas of attachment theory and describes how attachment style differences are manifested in intimate and sexual relationships. Research so far has been limited to studying the predicted link between sex and attachment in terms of broad descriptives, and it would benefit the literature to specify the processes and pathways that mediate the sex-attachment link. After a short discussion of the functional similarities between the sexual and the attachment systems, the article describes some specific--dynamical--models that focus on the emotional and cognitive-motivational processes through which attachment schemas influence sexual experiences. Such an emotion-motivational perspective on sex and attachment can help to organize theoretical ideas and empirical findings and eventually promote an integrative view on how attachment dynamics can interact with sexual experiences. PMID:22380584

  16. Cladding Attachment Over Thick Exterior Insulating Sheathing

    SciTech Connect

    Baker, P.; Eng, P.; Lepage, R.

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1. What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2. Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3. What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  17. Cladding Attachment Over Thick Exterior Insulating Sheathing

    SciTech Connect

    Baker, P.; Eng, P.; Lepage, R.

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1.What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2.Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3.What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  18. Implications of attachment theory for developmental psychopathology.

    PubMed

    Sroufe, L A; Carlson, E A; Levy, A K; Egeland, B

    1999-01-01

    Bowlby's attachment theory is a theory of psychopathology as well as a theory of normal development. It contains clear and specific propositions regarding the role of early experience in developmental psychopathology, the importance of ongoing context, and the nature of the developmental process underlying pathology. In particular, Bowlby argued that adaptation is always the joint product of developmental history and current circumstances (never either alone). Early experience does not cause later pathology in a linear way; yet, it has special significance due to the complex, systemic, transactional nature of development. Prior history is part of current context, playing a role in selection, engagement, and interpretation of subsequent experience and in the use of available environmental supports. Finally, except in very extreme cases, early anxious attachment is not viewed as psychopathology itself or as a direct cause of psychopathology but as an initiator of pathways probabilistically associated with later pathology. PMID:10208353

  19. Partner attachment and interpersonal characteristics.

    PubMed

    Kilmann, Peter R; Finch, Holmes; Parnell, Michele M; Downer, Jason T

    2013-01-01

    This study investigated partner attachment and interpersonal characteristics in 134 nonclinical couples in long-term marriages. Irrespective of gender, spouses with greater anxiety over abandonment or discomfort with closeness endorsed dysfunctional relationship beliefs to a greater extent. On the anxiety over abandonment dimension, husbands with higher scores were rated less aggressive, less controlling, and more rebellious, whereas wives with higher scores were rated more dependent, more self-critical, and less competitive. Husbands higher on discomfort with closeness were rated less cooperative and responsible and were rated more aggressive and rebellious. Matched secure couples reported lower marital dissatisfaction than matched insecure or mismatched couples. Future research should contrast samples of nonclinical and clinical couples by marital duration to identify specific partner behaviors that are likely to foster marital dissatisfaction within particular attachment pairings. The authors' findings suggest the importance of marital therapists being attuned to the attachment-related beliefs and interpersonal styles uniquely operating within each couple. PMID:23252639

  20. Attached-growth biological reactor

    SciTech Connect

    O'Brien, D.J.; Heiland, W.K.

    1991-12-16

    An attached growth biological reactor for the growth and harvesting of filamentous fungi has been developed. The reactor contains a rigid cylinder which is partially submerged and rotated in a biological medium containing nutrients for fungal growth and which has been inoculated with a filamentous fungal medium. The filamentous fungi attaches itself to and grows upon the cylinder wherein it is removed by use of a doctoring blade. The reactor can be operated in a continuous mode by continuously supplying oxygen and nutrients to the reactor.

  1. The Development and Neurobiology of Infant Attachment and Fear

    PubMed Central

    Landers, Margo S.; Sullivan, Regina M.

    2013-01-01

    Survival of altricial infants depends on attachment to the caregiver – a process that requires infants to identify, learn, remember, and approach their attachment figure. Here we review the neurobiology of attachment in infant rats where learning about the caregiver is supported by a specialized attachment neural circuitry to promote the infant-caregiver relationship. Specifically, the attachment circuit relies on infants acquiring learned preferences to the maternal odor, and this behavior is supported by the hyper-functioning locus coeruleus and generous amounts of norepinephrine to produce experience-induced changes in the olfactory bulb and anterior piriform cortex. Infants also possess a reduced ability to acquire learned aversions or fear, and this behavior is facilitated through attenuated amygdala plasticity to block fear learning. Presumably, this attachment circuitry constrains the infant animal to express only learned preferences regardless of the quality of care received. As pups mature, and begin to travel in and out of the nest, the specialized attachment learning becomes contextually confined to when pups are with the mother. Thus, when outside the nest, these older pups show learning more typical of adult learning, presumably to prepare for independent life outside the nest. The quality of attachment can alter this circuitry, with early life stress prematurely terminating the pups’ access to the attachment system through premature functional activation of the amygdala. Overall, the attachment circuit appears to have a dual function: keeping pups close to the caregiver but also to shape pups’ behavior to match the environment and define long-term emotion and cognition. PMID:22571921

  2. The Role of Parenting Sensitivity, Infant Temperament, and Dyadic Interaction in Attachment Theory and Assessment.

    ERIC Educational Resources Information Center

    Seifer, Ronald; Schiller, Masha

    1995-01-01

    Describes the core constructs of attachment theory, namely, the attachment system and secure-base behavior. Discusses contextual factors thought to be crucial in development of individual differences in attachment, especially maternal sensitivity, and considers child characteristics, especially temperament, that may contribute to the attachment…

  3. Attachment Processes in Eating Disorder and Depression.

    ERIC Educational Resources Information Center

    Cole-Detke, Holland; Kobak, Roger

    1996-01-01

    Examines the relationship between attachment strategies and symptom reporting among college women (N=61). The Adult Attachment Interview (AAI) was administered and interview transcripts were rated with the Attachment Interview Q-Sort. Findings support the hypothesis that secondary or defensive attachment strategies predispose individuals toward…

  4. Closeup detail of the jackstand head and the attach mechanism ...

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

    Close-up detail of the jack-stand head and the attach mechanism connection to the hoist attach point on the starboard forward fuselage of the Orbiter Discovery. Note the profile of the wing intersection with the fuselage and the payload bay door in an open position with the strongback support structure attached. This view was taken from a service platform in the Orbiter Processing Facility at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  5. Root canal retained restorations: 3. Root-face attachments.

    PubMed

    Dummer, P M; Edmunds, D H; Gidden, J R

    1990-10-01

    It has been common practice for many years to use retained roots to provide support and stability for partial or full dentures. The retention of such overdentures is greatly enhanced if the remaining roots are modified and restored with posts and root-face attachments. The final article in this series on root canal retained restorations classifies and describes some of the root-face attachments currently available, and also describes a number of prefabricated post systems with integral overdenture attachments. Guidelines for clinical and laboratory procedures are given. PMID:2097234

  6. Pressurizer with a mechanically attached surge nozzle thermal sleeve

    DOEpatents

    Wepfer, Robert M

    2014-03-25

    A thermal sleeve is mechanically attached to the bore of a surge nozzle of a pressurizer for the primary circuit of a pressurized water reactor steam generating system. The thermal sleeve is attached with a series of keys and slots which maintain the thermal sleeve centered in the nozzle while permitting thermal growth and restricting flow between the sleeve and the interior wall of the nozzle.

  7. Quick Attach Docking Interface for Lunar Electric Rover

    NASA Technical Reports Server (NTRS)

    Schuler, Jason M.; Nick, Andrew J.; Immer, Christopher; Mueller, Robert P.

    2010-01-01

    The NASA Lunar Electric Rover (LER) has been developed at Johnson Space Center as a next generation mobility platform. Based upon a twelve wheel omni-directional chassis with active suspension the LER introduces a number of novel capabilities for lunar exploration in both manned and unmanned scenarios. Besides being the primary vehicle for astronauts on the lunar surface, LER will perform tasks such as lunar regolith handling (to include dozing, grading, and excavation), equipment transport, and science operations. In an effort to support these additional tasks a team at the Kennedy Space Center has produced a universal attachment interface for LER known as the Quick Attach. The Quick Attach is a compact system that has been retro-fitted to the rear of the LER giving it the ability to dock and undock on the fly with various implements. The Quick Attach utilizes a two stage docking approach; the first is a mechanical mate which aligns and latches a passive set of hooks on an implement with an actuated cam surface on LER. The mechanical stage is tolerant to misalignment between the implement and the LER during docking and once the implement is captured a preload is applied to ensure a positive lock. The second stage is an umbilical connection which consists of a dust resistant enclosure housing a compliant mechanism that is optionally actuated to mate electrical and fluid connections for suitable implements. The Quick Attach system was designed with the largest foreseen input loads considered including excavation operations and large mass utility attachments. The Quick Attach system was demonstrated at the Desert Research And Technology Studies (D-RA TS) field test in Flagstaff, AZ along with the lightweight dozer blade LANCE. The LANCE blade is the first implement to utilize the Quick Attach interface and demonstrated the tolerance, speed, and strength of the system in a lunar analog environment.

  8. Sexual size and shape dimorphism and allometric scaling patterns in head traits in the New Zealand common gecko Woodworthia maculatus.

    PubMed

    Kelly, Clint D

    2015-08-01

    Sexual dimorphism in shape and size is widespread across animal taxa and arises when natural or sexual selection operates differently on the sexes. Male and female common geckos (Woodworthia maculatus; formerly Hoplodactylus maculatus) in New Zealand do not appear to experience different viability selection pressure, nor do males appear to be under intense pre-copulatory sexual selection. It was therefore predicted that this species would be sexually monomorphic with regard to body size and the size and shape of the head. In line with the prediction, there was no sexual difference in head width, depth, or length or in lateral head shape. However, contrary to prediction, males had a larger body and lateral head size than females. This study suggests that males, at least on Maud Island, NZ, might be under stronger pre-copulatory sexual selection than previously recognized and thus have evolved larger heads (i.e. lateral head size) for use in male combat for females. Allometric scaling patterns do not differ between the sexes and suggest that head width and depth are under directional selection whereas lateral head size is under stabilizing selection. Diet ecology - an agent of natural selection common to both sexes - is likely largely responsible for the observed patterns of head size and shape and the lack of sexual dimorphism in them. PMID:25958103

  9. Gecko Proteins Exert Anti-Tumor Effect against Cervical Cancer Cells Via PI3-Kinase/Akt Pathway

    PubMed Central

    Jeong, Ae-Jin; Chung, Chung-Nam; Kim, Hye-Jin; Bae, Kil Soo; Choi, Song; Jun, Woo Jin; Shim, Sang In; Kang, Tae-Hong; Leem, Sun-Hee

    2012-01-01

    Anti-tumor activity of the proteins from Gecko (GP) on cervical cancer cells, and its signaling mechanisms were assessed by viable cell counting, propidium iodide (PI) staining, and Western blot analysis. GP induced the cell death of HeLa cells in a dose-dependent manner while it did not affect the viability of normal cells. Western blot analysis showed that GP decreased the activation of Akt, and co-administration of GP and Akt inhibitors synergistically exerted anti-tumor activities on HeLa cells, suggesting the involvement of PI3-kinase/Akt pathway in GP-induced cell death of the cancer cells. Indeed, the cytotoxic effect of GP against HeLa cells was inhibited by overexpression of constituvely active form of Akt in HeLa cells. The candidates of the functional proteins in GP were analyzed by Mass-spectrum. Taken together, our results suggest that GP elicits anti-tumor activity against HeLa cells by inhibition of PI3-kinase/Akt pathway. PMID:23118562

  10. Gecko Proteins Exert Anti-Tumor Effect against Cervical Cancer Cells Via PI3-Kinase/Akt Pathway.

    PubMed

    Jeong, Ae-Jin; Chung, Chung-Nam; Kim, Hye-Jin; Bae, Kil Soo; Choi, Song; Jun, Woo Jin; Shim, Sang In; Kang, Tae-Hong; Leem, Sun-Hee; Chung, Jin Woong

    2012-10-01

    Anti-tumor activity of the proteins from Gecko (GP) on cervical cancer cells, and its signaling mechanisms were assessed by viable cell counting, propidium iodide (PI) staining, and Western blot analysis. GP induced the cell death of HeLa cells in a dose-dependent manner while it did not affect the viability of normal cells. Western blot analysis showed that GP decreased the activation of Akt, and co-administration of GP and Akt inhibitors synergistically exerted anti-tumor activities on HeLa cells, suggesting the involvement of PI3-kinase/Akt pathway in GP-induced cell death of the cancer cells. Indeed, the cytotoxic effect of GP against HeLa cells was inhibited by overexpression of constituvely active form of Akt in HeLa cells. The candidates of the functional proteins in GP were analyzed by Mass-spectrum. Taken together, our results suggest that GP elicits anti-tumor activity against HeLa cells by inhibition of PI3-kinase/Akt pathway. PMID:23118562

  11. Molecular characterization of thyroid hormone receptors from the leopard gecko, and their differential expression in the skin.

    PubMed

    Kanaho, Yoh-Ichiro; Endo, Daisuke; Park, Min Kyun

    2006-06-01

    Thyroid hormones (THs) play crucial roles in various developmental and physiological processes in vertebrates, including squamate reptiles. The effect of THs on shedding frequency is interesting in Squamata, since the effects on lizards are quite the reverse of those in snakes: injection of thyroxine increases shedding frequency in lizards, but decreases it in snakes. However, the mechanism underlying this differential effect remains unclear. To facilitate the investigation of the molecular mechanism of the physiological functions of THs in Squamata, their two specific receptor (TRalpha and beta) cDNAs, which are members of the nuclear hormone receptor superfamily, were cloned from a lizard, the leopard gecko, Eublepharis macularius. This is the first molecular cloning of thyroid hormone receptors (TRs) from reptiles. The deduced amino acid sequences showed high identity with those of other species, especially in the C and E/F domains, which are characteristic domains in nuclear hormone receptors. Expression analysis revealed that TRs were widely expressed in many tissues and organs, as in other animals. To analyze their role in the skin, temporal expression analysis was performed by RT-PCR, revealing that the two TRs had opposing expression patterns: TRalpha was expressed more strongly after than before skin shedding, whereas TRbeta was expressed more strongly before than after skin shedding. This provides good evidence that THs play important roles in the skin, and that the roles of their two receptor isoforms are distinct from each other. PMID:16849843

  12. Light and transmission electron microscopic studies of a haemogregarine in naturally infected fan-footed gecko (Ptyodactylus hasselquistii).

    PubMed

    Hussein, Abdel-Nasser A

    2006-04-01

    The present study focuses on and describes the developmental stages of a haemogregarine species in the blood and tissues of the gecko Ptyodactylus hasselquistii. The blood stages were differentiated into two forms: a short gamont measuring 11.87 x 6.42 microm and a banana-shaped mature gamont measuring 14.13 x 10.03 microm in length and width, respectively. Both erythrocytes and leucocytes had been invaded. The parasitaemia level is up to 410 per 10,000 erythrocytes counted. The gamont has a karyolytic effect on the host cell nucleus. Merogony occurred in the parenchyma cells of liver and the endothelial cells of the lung. The meronts in the lung were found in two forms: the micromeront measured 14.93x13.14 microm and produced a few numbers (average 4) of macromerozoites. The macromeront measured 26.3 x 16 microm and produced more small-sized merozoites (average 11.5), or micromerozoites. On the ultrastructural level, merozoites have a pellicle, which consists of an outer and inner membrane. The merozoites are nearly identical to the blood stages of the parasite. PMID:16416117

  13. Improving controllable adhesion on both rough and smooth surfaces with a hybrid electrostatic/gecko-like adhesive.

    PubMed

    Ruffatto, Donald; Parness, Aaron; Spenko, Matthew

    2014-04-01

    This paper describes a novel, controllable adhesive that combines the benefits of electrostatic adhesives with gecko-like directional dry adhesives. When working in combination, the two technologies create a positive feedback cycle whose adhesion, depending on the surface type, is often greater than the sum of its parts. The directional dry adhesive brings the electrostatic adhesive closer to the surface, increasing its effect. Similarly, the electrostatic adhesion helps engage more of the directional dry adhesive fibrillar structures, particularly on rough surfaces. This paper presents the new hybrid adhesive's manufacturing process and compares its performance to three other adhesive technologies manufactured using a similar process: reinforced PDMS, electrostatic and directional dry adhesion. Tests were performed on a set of ceramic tiles with varying roughness to quantify its effect on shear adhesive force. The relative effectiveness of the hybrid adhesive increases as the surface roughness is increased. Experimental data are also presented for different substrate materials to demonstrate the enhanced performance achieved with the hybrid adhesive. Results show that the hybrid adhesive provides up to 5.1× greater adhesion than the electrostatic adhesive or directional dry adhesive technologies alone. PMID:24451392

  14. ACTH-induced stress response during pregnancy in a viviparous gecko: no observed effect on offspring quality.

    PubMed

    Preest, Marion R; Cree, Alison; Tyrrell, Claudine L

    2005-09-01

    The typical stress response in reptiles involves the release of corticosterone from the adrenal glands. Elevated maternal concentrations of corticosterone in mammals during pregnancy may have deleterious effects on offspring fitness, and recent work has shown a suppression of the hormonal response to stress during pregnancy in rats. Little is known about the influence of reproductive state on the secretion of corticosterone in viviparous reptiles or on the effects of high levels of corticosterone during reproduction on the developing embryos. We examined whether New Zealand common geckos (Hoplodactylus maculatus), pregnant with embryos at stages 34-35 of development, secrete corticosterone in response to adrenocorticotrophic hormone (ACTH) and whether an ACTH-induced increase in maternal corticosterone affects the outcome of pregnancy. Corticosterone concentrations in pregnant lizards increased more than seven-fold over basal levels following injection of ACTH. However, there were no significant effects of elevated corticosterone on the duration or success of pregnancy, or on various morphological measures, growth, or sprint speed of the offspring. This may reflect a lack of sensitivity of relevant embryonic tissues to corticosterone under the conditions of the present experiment or an ability of the embryos to bind, degrade, or restrict placental transport of corticosterone. Future studies should investigate the possibility of corticosteroid effects on other offspring tissues, including effects in adult life. PMID:16106406

  15. Independent Transitions between Monsoonal and Arid Biomes Revealed by Systematic Revison of a Complex of Australian Geckos (Diplodactylus; Diplodactylidae)

    PubMed Central

    Oliver, Paul M.; Couper, Patrick J.; Pepper, Mitzy

    2014-01-01

    How the widespread expansion and intensification of aridity through the Neogene has shaped the Austral biota is a major question in Antipodean biogeography. Lineages distributed across wide aridity gradients provide opportunities to examine the timing, frequency, and direction of transitions between arid and mesic regions. Here, we use molecular genetics and morphological data to investigate the systematics and biogeography of a nominal Australian gecko species (Diplodactylus conspicillatus sensu lato) with a wide distribution spanning most of the Australian Arid Zone (AAZ) and Monsoonal Tropics (AMT). Our data support a minimum of seven genetically distinct and morphologically diagnosable taxa; we thus redefine the type species, ressurrect three names from synonymy, and describe three new species. Our inferred phylogeny suggests the history and diversification of lineages in the AAZ and AMT are intimately linked, with evidence of multiple independent interchanges since the late Miocene. However, despite this shared history, related lineages in these two regions also show evidence of broadly contrasting intra-regional responses to aridification; vicarance and speciation in older and increasingly attenuated mesic regions, versus a more dynamic history including independent colonisations and recent range expansions in the younger AAZ. PMID:25493936

  16. Constraints on temperature-dependent sex determination in the leopard gecko ( Eublepharis macularius): response to Kratochvil et al.

    NASA Astrophysics Data System (ADS)

    Huang, Victoria; Sakata, Jon T.; Rhen, Turk; Coomber, Patricia; Simmonds, Sarah; Crews, David

    2008-12-01

    Kratochvil et al. (Naturwissenschaften 95:209 215, 2008) reported recently that in the leopard gecko ( Eublepharis macularius) of the family Eublepharidae with temperature-dependent sex determination (TSD), clutches in which eggs were incubated at the same temperature produce only same-sex siblings. Interpreting this result in light of studies of sex steroid hormone involvement in sex determination, they suggested that maternally derived yolk steroid hormones could constrain sex-determining mechanisms in TSD reptiles. We have worked extensively with this species and have routinely incubated clutches at constant temperatures. To test the consistency of high frequency same-sex clutches across different incubation temperatures, we examined our records of clutches at the University of Texas at Austin from 1992 to 2001. We observed that clutches in which eggs were incubated at the same incubation temperature produced mixed-sex clutches as well as same-sex clutches. Furthermore, cases in which eggs within a clutch were separated and incubated at different temperatures produced the expected number of mixed-sex clutches. These results suggest that maternal influences on sex determination are secondary relative to incubation temperature effects.

  17. Improving controllable adhesion on both rough and smooth surfaces with a hybrid electrostatic/gecko-like adhesive

    PubMed Central

    Ruffatto, Donald; Parness, Aaron; Spenko, Matthew

    2014-01-01

    This paper describes a novel, controllable adhesive that combines the benefits of electrostatic adhesives with gecko-like directional dry adhesives. When working in combination, the two technologies create a positive feedback cycle whose adhesion, depending on the surface type, is often greater than the sum of its parts. The directional dry adhesive brings the electrostatic adhesive closer to the surface, increasing its effect. Similarly, the electrostatic adhesion helps engage more of the directional dry adhesive fibrillar structures, particularly on rough surfaces. This paper presents the new hybrid adhesive's manufacturing process and compares its performance to three other adhesive technologies manufactured using a similar process: reinforced PDMS, electrostatic and directional dry adhesion. Tests were performed on a set of ceramic tiles with varying roughness to quantify its effect on shear adhesive force. The relative effectiveness of the hybrid adhesive increases as the surface roughness is increased. Experimental data are also presented for different substrate materials to demonstrate the enhanced performance achieved with the hybrid adhesive. Results show that the hybrid adhesive provides up to 5.1× greater adhesion than the electrostatic adhesive or directional dry adhesive technologies alone. PMID:24451392

  18. Stud attachments for the mandibular implant-retained overdentures: Prosthetic complications. A literature review.

    PubMed

    Daou, Elie E

    2013-04-01

    A plethora of attachment systems for mandibular two-implant overdentures is currently available often without evidence-based support. Technical aspects are now parameters considered when choosing the appropriate attachment. Despite the increasing use of the Locator attachments, studies regarding their properties remain scarce. Peer reviewed articles published in English up to 2011, were identified through a MEDLINE search (Pubmed and Elsevier) and a hand search of relevant textbooks and annual publications. Emphasis was made on the technical complications as well as the loss of retention related to the attachments in implant-retained overdentures, primarily the Locator attachment. The evaluation of the long-term outcome of implant overdentures and complications associated with different attachment systems may provide useful guidelines for the clinician in selecting the type of attachment system and overdenture design. PMID:23960557

  19. Stud attachments for the mandibular implant-retained overdentures: Prosthetic complications. A literature review

    PubMed Central

    Daou, Elie E.

    2013-01-01

    A plethora of attachment systems for mandibular two-implant overdentures is currently available often without evidence-based support. Technical aspects are now parameters considered when choosing the appropriate attachment. Despite the increasing use of the Locator attachments, studies regarding their properties remain scarce. Peer reviewed articles published in English up to 2011, were identified through a MEDLINE search (Pubmed and Elsevier) and a hand search of relevant textbooks and annual publications. Emphasis was made on the technical complications as well as the loss of retention related to the attachments in implant-retained overdentures, primarily the Locator attachment. The evaluation of the long-term outcome of implant overdentures and complications associated with different attachment systems may provide useful guidelines for the clinician in selecting the type of attachment system and overdenture design. PMID:23960557

  20. Thinking of attachments reduces noradrenergic stress response.

    PubMed

    Bryant, Richard A; Chan, Lilian

    2015-10-01

    Although there is much evidence that activating mental representations of attachments figure is beneficial for psychological health and can reduce stress response, no research has directly investigated whether attachment activation can ameliorate hormonal stress response. This study investigated whether activating an attachment figure or a non-attachment figure following administration of a socially evaluated cold pressor test to elicit stress impacted on glucocorticoid and noradrenergic response. Participants (N = 61) provided baseline salivary samples, underwent a cold pressor test, then imagined an attachment or non-attachment figure, and finally provided subsequent saliva samples. Participants who imagined a non-attachment figure had greater noradrenergic response following the stressor than those who imagined an attachment figure. These findings highlight that activating attachment representations can ameliorate the immediate noradrenergic stress response. PMID:26115145

  1. Effects of certain control-system nonlinearities on stability and pointing of an attached double-gimbal experiment package in presence of random crew-motion disturbances

    NASA Technical Reports Server (NTRS)

    Shaughnessy, J. D.; Groom, N. J.; Nene, V. D.

    1973-01-01

    The effects of two types of control-system nonlinearities, sensor deadband and actuator breakout torque, on the pointing capability of a Apollo Telescope Mount (ATM) double-gimbal experiment isolation and control system are investigated. A composite structural model of a flexible experiment package connected through frictionless double gimbals to a flexible carrier vehicle is used for this investigation. Contributions of the primary carrier control system to experiment pointing are neglected. Pointing errors onboard the experiment package due to random crew-motion input into the carrier vehicle are computed. A stability investigation is performed to verify control-system stability with nominal nonlinearities and gains. Indications are that there is no stability problem due to the nonlinearities. A nonlinearity sensitivity study is carried out to determine the effects on pointing accuracy. Its results indicate that nominal ATM control system nonlinearities limit the pointing accuracy to approximately 0.4 arc second in the presence of crew motion. Methods of reducing the error to less than 0.1 arc second are discussed.

  2. Domain Walls with Strings Attached

    SciTech Connect

    Shmakova, Marina

    2001-08-20

    We have constructed a bulk and brane action of IIA theory which describes a pair of BPS domain walls on S{sub 1}/Z{sub 2}, with strings attached. The walls are given by two orientifold O8-planes with coincident D8-branes and F1-D0-strings are stretched between the walls. This static configuration satisfies all matching conditions for the string and domain wall sources and has 1/4 of unbroken supersymmetry.

  3. Magnetically Attached Multifunction Maintenance Rover

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Joffe, Benjamin

    2005-01-01

    A versatile mobile telerobot, denoted the magnetically attached multifunction maintenance rover (MAGMER), has been proposed for use in the inspection and maintenance of the surfaces of ships, tanks containing petrochemicals, and other large ferromagnetic structures. As its name suggests, this robot would utilize magnetic attraction to adhere to a structure. As it moved along the surface of the structure, the MAGMER would perform tasks that could include close-up visual inspection by use of video cameras, various sensors, and/or removal of paint by water-jet blasting, laser heating, or induction heating. The water-jet nozzles would be mounted coaxially within compressed-air-powered venturi nozzles that would collect the paint debris dislodged by the jets. The MAGMER would be deployed, powered, and controlled from a truck, to which it would be connected by hoses for water, compressed air, and collection of debris and by cables for electric power and communication (see Figure 1). The operation of the MAGMER on a typical large structure would necessitate the use of long cables and hoses, which can be heavy. To reduce the load of the hoses and cables on the MAGMER and thereby ensure its ability to adhere to vertical and overhanging surfaces, the hoses and cables would be paid out through telescopic booms that would be parts of a MAGMER support system. The MAGMER would move by use of four motorized, steerable wheels, each of which would be mounted in an assembly that would include permanent magnets and four pole pieces (see Figure 2). The wheels would protrude from between the pole pieces by only about 3 mm, so that the gap between the pole pieces and the ferromagnetic surface would be just large enough to permit motion along the surface but not so large as to reduce the magnetic attraction excessively. In addition to the wheel assemblies, the MAGMER would include magnetic adherence enhancement fixtures, which would comprise arrays of permanent magnets and pole pieces

  4. Eardrum-inspired active sensors for self-powered cardiovascular system characterization and throat-attached anti-interference voice recognition.

    PubMed

    Yang, Jin; Chen, Jun; Su, Yuanjie; Jing, Qingshen; Li, Zhaoling; Yi, Fang; Wen, Xiaonan; Wang, Zhaona; Wang, Zhong Lin

    2015-02-25

    The first bionic membrane sensor based on triboelectrification is reported for self-powered physiological and behavioral measurements such as local internal body pressures for non-invasive human health assessment. The sensor can also be for self-powered anti-interference throat voice recording and recognition, as well as high-accuracy multimodal biometric authentication, thus potentially expanding the scope of applications in self-powered wearable medical/health monitoring, interactive input/control devices as well as accurate, reliable, and less intrusive biometric authentication systems. PMID:25640534

  5. After Love: Attachment Styles and Grief Themes.

    ERIC Educational Resources Information Center

    Pistole, M. Carole

    1996-01-01

    Examines the association of attachment organization and recalled grief responses following the dissolution of a romantic relationship. Data based on college students' (N=118) responses resulted in four interpretable grief themes. Preoccupied attachment predicted self-reproach, fearful attachment predicted partner blame, whereas both fearful and…

  6. Attachment in Deaf Mothers and Their Children

    ERIC Educational Resources Information Center

    Leigh, Irene W.; Brice, Patrick J.; Meadow-Orlans, Kathryn

    2004-01-01

    In attachment research, there has been a growing interest in how adults conceptualize their relationships with their own parents as well as in the transmission of attachment status from parent to child and the variables that influence that transmission. The primary goal of the present study was to examine the transmission of attachment from deaf…

  7. Genetic and Environmental Influence on Attachment Disorganization

    ERIC Educational Resources Information Center

    Spangler, Gottfried; Johann, Monika; Ronai, Zsolt; Zimmermann, Peter

    2009-01-01

    Background: Empirical studies demonstrate that maternal sensitivity is associated with attachment security in infancy, while maternal frightening/frightened behavior is related to attachment disorganization. However, attachment disorganization is also predicted by individual dispositions in infancy. Indeed, recent studies indicate a link between…

  8. Attachment in Middle Childhood: Progress and Prospects

    ERIC Educational Resources Information Center

    Bosmans, Guy; Kerns, Kathryn A.

    2015-01-01

    Contrary to the substantial amount of research on infant, preschool, adolescent, and adult attachment, middle childhood has long been neglected by the international attachment research community. In the past two decades, however, there has been a steep increase in research focusing on middle childhood attachment. This article provides an overview…

  9. Adolescents' Attachment and Coping with Stress

    ERIC Educational Resources Information Center

    Howard, Michelle S.; Medway, Frederic J.

    2004-01-01

    This study examined how high school students cope with stress as a function of their attachment style. Data were gathered from 75 adolescent-parent pairs in Texas and included measures of attachment, coping style, life stress, and whom the respondent would turn to in times of stress. Adolescents' attachment security was positively related to…

  10. Attachment: Building Secure Relationships in Early Childhood.

    ERIC Educational Resources Information Center

    Harrison, Linda

    2003-01-01

    Attachment describes the unique human ability to form lasting relationships with others, and to maintain these relationships over time and distance. Research into attachment has shown that children have the potential to form many attachment relationships, and that each relationship can contribute to the child's growing sense of self. This booklet…

  11. Tendon-to-Bone Attachment: From Development to Maturity

    PubMed Central

    Zelzer, Elazar; Blitz, Einat; Killian, Megan L.; Thomopoulos, Stavros

    2014-01-01

    The attachment between tendon and bone occurs across a complex transitional tissue that minimizes stress concentrations and allows for load transfer between muscles and skeleton. This unique tissue cannot be reconstructed following injury, leading to high incidence of recurrent failure and stressing the need for new clinical approaches. This review describes the current understanding of the development and function of the attachment site between tendon and bone. The embryonic attachment unit, namely, the tip of the tendon and the bone eminence into which it is inserted, was recently shown to develop modularly from a unique population of Sox9- and Scx-positive cells, which are distinct from tendon fibroblasts and chondrocytes. The fate and differentiation of these cells is regulated by transforming growth factor beta and bone morphogenetic protein signaling, respectively. Muscle loads are then necessary for the tissue to mature and mineralize. Mineralization of the attachment unit, which occurs postnatally at most sites, is largely controlled by an Indian hedgehog/parathyroid hormone-related protein feedback loop. A number of fundamental questions regarding the development of this remarkable attachment system require further study. These relate to the signaling mechanism that facilitates the formation of an interface with a gradient of cellular and extracellular phenotypes, as well as to the interactions between tendon and bone at the point of attachment. PMID:24677726

  12. A new leaf-tailed gecko of the Uroplatus ebenaui group (Squamata: Gekkonidae) from Madagascar's central eastern rainforests.

    PubMed

    Ratsoavina, Fanomezana Mihaja; Ranjanaharisoa, Fiadanantsoa Andrianja; Glaw, Frank; Raselimanana, Achille P; Miralles, Aurélien; Vences, Miguel

    2015-01-01

    We describe a new leaf-tailed gecko species of the Uroplatus ebenaui group from the eastern central rainforests of Madagascar, which had previously been considered as a confirmed candidate species. Our description of Uroplatus fiera sp. nov. relies on integrating evidence from molecular and morphological characters and is based on newly collected material from two localities. A phylogenetic analysis based on multiple mitochondrial DNA fragments places the new species as sister to a lineage of uncertain status (Uroplatus ebenaui [Ca8]), and the clade consisting of these two lineages is sister to a further undescribed candidate species (U. ebenaui [Ca1]). This entire clade is sister to U. phantasticus plus another candidate species. The new species differs from these close relatives, and all other congenerics, by strong differences in DNA sequences of mitochondrial genes (>8.5% uncorrected p-distance in 16S rDNA to all nominal species of the genus) and lacks shared alleles with any of the nominal species in the nuclear CMOS gene. From its closest relatives the new species further differs in its much smaller tail size (relative to U. phantasticus), and a narrower tail, fewer supralabials, and more toe lamellae (relative to U. ebenaui [Ca1]). Morphologically the new species is most similar to U. ebenaui but differs in its larger body size and unpigmented oral mucosa. Given its distribution in central eastern Madagascar, with records from near Fierenana and Ambatovy, its range overlaps with that of U. phantasticus. Based on examination of the U. phantasticus holotype, we confirm that this latter has a blackish pigmented oral mucosa as do those specimens typically attributed to this nomen, thereby confirming its distinctness from U. fiera sp. nov., in which the mucosa is unpigmented. PMID:26623762

  13. Offspring sex in a TSD gecko correlates with an interaction between incubation temperature and yolk steroid hormones

    NASA Astrophysics Data System (ADS)

    Ding, Guo-Hua; Yang, Jing; Wang, Jin; Ji, Xiang

    2012-12-01

    We incubated eggs of the Japanese gecko Gekko japonicus at three temperatures, and measured yolk testosterone (T) and 17β-estradiol (E2) levels at three time points in embryonic development (oviposition, 1/3 of incubation, and 2/3 of incubation), to examine whether maternal influence on offspring sex via yolk steroid hormone deposition is significant in the species. Eggs incubated at 24 °C and 32 °C produced mostly females, and eggs incubated at 28 °C almost a 50:50 sex ratio of hatchlings. Female-producing eggs were larger than male-producing eggs. Clutches in which eggs were incubated at the same temperature produced mostly same-sex siblings. Yolk T level at laying was negatively related to eggs mass, and yolk E2/T ratio was positively related to egg mass. Results of two-way ANOVA with incubation temperature and stage as the factors show that: yolk E2 level was higher at 32 °C than at 24 °C; yolk T level was higher, whereas yolk E2/T ratio was smaller, at 28 °C than at 24 °C; yolk E2 and T levels were higher at 2/3 than at 1/3 of incubation. Our data in G. japonucus show that: (1) maternal influence on offspring sex via yolk steroid hormone deposition is significant; (2) incubation temperature affects the dynamics of developmental changes in yolk steroid hormones; (3) influences of yolk steroid hormones on offspring sex are secondary relative to incubation temperature effects; and (4) offspring sex correlates with an interaction between incubation temperature and yolk steroid hormones.

  14. Out of Arabia: a complex biogeographic history of multiple vicariance and dispersal events in the gecko genus Hemidactylus (Reptilia: Gekkonidae).

    PubMed

    Smíd, Jiří; Carranza, Salvador; Kratochvíl, Lukáš; Gvoždík, Václav; Nasher, Abdul Karim; Moravec, Jiří

    2013-01-01

    The geological history of the Arabian Peninsula has played a crucial role in shaping current diversity and distribution patterns of many Arabian and African faunal elements. The gecko genus Hemidactylus is not an exception. In this study, we provide an insight into the phylogeny and systematics of 45 recognized species of the so-called Arid clade of the genus Hemidactylus from Arabia, the Horn of Africa, the Levant and Iran. The material comprises 358 specimens sequenced for up to two mitochondrial (12S rRNA, cytochrome b) and four nuclear (mc1r, cmos, rag1, rag2) genes with 4766 bp of the concatenated alignment length. A robust calibrated phylogeny and reconstruction of historical biogeography are inferred. We link the history of this genus with major geological events that occurred in the region within the last 30 million years. Two basal divergences correspond with the break-ups of the Arabian and African landmasses and subsequent separation of Socotra from the Arabian mainland, respectively, segregating the genus by means of vicariance. Formation of the Red Sea led to isolation and subsequent radiation in the Arabian Peninsula, which was followed by multiple independent expansions: 13.1 Ma to Iran; 9.8 Ma to NE Africa; 8.2 to Socotra Archipelago; 7-7.3 Ma two colonizations to the Near East; 5.9 Ma to NE Africa; and 4.1 to Socotra. Moreover, using multiple genetic markers we detected cryptic diversity within the genus, particularly in south-western Arabia and the Ethiopian highlands, and confirmed the existence of at least seven new species in the area. These findings highlight the role of Arabia and the Horn of Africa as an important Hemidactylus diversity hotspot. PMID:23724016

  15. Out of Arabia: A Complex Biogeographic History of Multiple Vicariance and Dispersal Events in the Gecko Genus Hemidactylus (Reptilia: Gekkonidae)

    PubMed Central

    Šmíd, Jiří; Carranza, Salvador; Kratochvíl, Lukáš; Gvoždík, Václav; Nasher, Abdul Karim; Moravec, Jiří

    2013-01-01

    The geological history of the Arabian Peninsula has played a crucial role in shaping current diversity and distribution patterns of many Arabian and African faunal elements. The gecko genus Hemidactylus is not an exception. In this study, we provide an insight into the phylogeny and systematics of 45 recognized species of the so-called Arid clade of the genus Hemidactylus from Arabia, the Horn of Africa, the Levant and Iran. The material comprises 358 specimens sequenced for up to two mitochondrial (12S rRNA, cytochrome b) and four nuclear (mc1r, cmos, rag1, rag2) genes with 4766 bp of the concatenated alignment length. A robust calibrated phylogeny and reconstruction of historical biogeography are inferred. We link the history of this genus with major geological events that occurred in the region within the last 30 million years. Two basal divergences correspond with the break-ups of the Arabian and African landmasses and subsequent separation of Socotra from the Arabian mainland, respectively, segregating the genus by means of vicariance. Formation of the Red Sea led to isolation and subsequent radiation in the Arabian Peninsula, which was followed by multiple independent expansions: 13.1 Ma to Iran; 9.8 Ma to NE Africa; 8.2 to Socotra Archipelago; 7–7.3 Ma two colonizations to the Near East; 5.9 Ma to NE Africa; and 4.1 to Socotra. Moreover, using multiple genetic markers we detected cryptic diversity within the genus, particularly in south-western Arabia and the Ethiopian highlands, and confirmed the existence of at least seven new species in the area. These findings highlight the role of Arabia and the Horn of Africa as an important Hemidactylus diversity hotspot. PMID:23724016

  16. Phylogenetic relationships of Semaphore geckos (Squamata: Sphaerodactylidae: Pristurus) with an assessment of the taxonomy of Pristurus rupestris.

    PubMed

    Badiane, Arnaud; Garcia-Porta, Joan; Červenka, Jan; Kratochvíl, Lukáš; Sindaco, Roberto; Robinson, Michael D; Morales, Hernan; Mazuch, Tomáš; Price, Thomas; Amat, Fèlix; Shobrak, Mohammed Y; Wilms, Thomas; Simó-Riudalbas, Marc; Ahmadzadeh, Faraham; Papenfuss, Theodore J; Cluchier, Alexandre; Viglione, Julien; Carranza, Salvador

    2014-01-01

    A molecular phylogeny of the sphaerodactylid geckos of the genus Pristurus is inferred based on an alignment of 1845 base pairs (bp) of concatenated mitochondrial (12S) and nuclear (acm4, cmos, rag1 and rag2) genes for 80 individuals, representing 18 of the 23-26 species, and the three subspecies of P. rupestris. The results indicate that P. rupestris is polyphyletic and includes two highly divergent clades: the eastern clade, found in coastal Iran and throughout the Hajar Mountain range in northern Oman and eastern UAE; and the western clade, distributed from central coastal Oman, through Yemen, Saudi Arabia and north to southern Jordan. Inferred haplotype networks for the four nuclear genes show that the eastern and western clades of "P. rupestris" are highly differentiated and do not share any alleles. Moreover, although the two clades are differentiated by a morphological multivariate analysis, no one character or set of characters was found to be diagnostic. Based on the molecular analysis of specimens from the type locality of P. rupestris rupestris, the name P. rupestris is applied to the eastern clade. The name that should apply to the western clade cannot be clarified until morphological and genetic data for "P. rupestris" is available from the vicinity of Bosaso, Somalia, and therefore we refer to it as Pristurus sp. 1. The phylogenetic tree of Pristurus supports the hypothesis that P. celerrimus is sister to all the other species in the analyses and that the Socotra Archipelago was independently colonized a minimum of two times. PMID:25081434

  17. Chloride binding regulates the Schiff base pK in gecko P521 cone-type visual pigment.

    PubMed

    Yuan, C; Kuwata, O; Liang, J; Misra, S; Balashov, S P; Ebrey, T G

    1999-04-01

    The binding of chloride is known to shift the absorption spectrum of most long-wavelength-absorbing cone-type visual pigments roughly 30 nm to the red. We determined that the chloride binding constant for this color shift in the gecko P521 visual pigment is 0.4 mM at pH 6.0. We found an additional effect of chloride on the P521 pigment: the apparent pKa of the Schiff base in P521 is greatly increased as the chloride concentration is increased. The apparent Schiff base pKa shifts from 8.4 for the chloride-free form to >10.4 for the chloride-bound form. We show that this shift is due to chloride binding to the pigment, not to the screening of the membrane surface charges by chloride ions. We also found that at high pH, the absorption maximum of the chloride-free pigment shifts from 495 to 475 nm. We suggest that the chloride-dependent shift of the apparent Schiff base pKa is due to the deprotonation of a residue in the chloride binding site with a pKa of ca. 8.5, roughly that of the Schiff base in the absence of chloride. The deprotonation of this site results in the formation of the 475 nm pigment and a 100-fold decrease in the pigment's ability to bind chloride. Increasing the concentration of chloride results in the stabilization of the protonated state of this residue in the chloride binding site and thus increased chloride binding with an accompanying increase in the Schiff base pK. PMID:10194387

  18. Combining Phylogeography with Distribution Modeling: Multiple Pleistocene Range Expansions in a Parthenogenetic Gecko from the Australian Arid Zone

    PubMed Central

    Strasburg, Jared L.; Kearney, Michael; Moritz, Craig; Templeton, Alan R.

    2007-01-01

    Phylogenetic and geographic evidence suggest that many parthenogenetic organisms have evolved recently and have spread rapidly. These patterns play a critical role in our understanding of the relative merits of sexual versus asexual reproductive modes, yet their interpretation is often hampered by a lack of detail. Here we present a detailed phylogeographic study of a vertebrate parthenogen, the Australian gecko Heteronotia binoei, in combination with statistical and biophysical modeling of its distribution during the last glacial maximum. Parthenogenetic H. binoei occur in the Australian arid zone and have the widest range of any known vertebrate parthenogen. They are broadly sympatric with their sexual counterparts, from which they arose via hybridization. We have applied nested clade phylogeographic, effective migration, and mismatch distribution analyses to mitochondrial DNA (mtDNA) sequences obtained for 319 individuals sampled throughout the known geographic ranges of two parthenogenetic mitochondrial lineages. These analyses provide strong evidence for past range expansion events from west to east across the arid zone, and for continuing eastward range expansion. Parthenogen formation and range expansion events date to the late Pleistocene, with one lineage expanding from the northwest of its present range around 240,000 years ago and the second lineage expanding from the far west around 70,000 years ago. Statistical and biophysical distribution models support these inferences of recent range expansion, with suitable climatic conditions during the last glacial maximum most likely limited to parts of the arid zone north and west of much of the current ranges of these lineages. Combination of phylogeographic analyses and distribution modeling allowed considerably stronger inferences of the history of this complex than either would in isolation, illustrating the power of combining complementary analytical approaches. PMID:17712408

  19. Split ring containment attachment device

    DOEpatents

    Sammel, Alfred G.

    1996-01-01

    A containment attachment device 10 for operatively connecting a glovebag 200 to plastic sheeting 100 covering hazardous material. The device 10 includes an inner split ring member 20 connected on one end 22 to a middle ring member 30 wherein the free end 21 of the split ring member 20 is inserted through a slit 101 in the plastic sheeting 100 to captively engage a generally circular portion of the plastic sheeting 100. A collar potion 41 having an outer ring portion 42 is provided with fastening means 51 for securing the device 10 together wherein the glovebag 200 is operatively connected to the collar portion 41.

  20. Preferred Attachment in Affiliation Networks

    NASA Astrophysics Data System (ADS)

    Bloznelis, Mindaugas; Götze, Friedrich

    2014-08-01

    Vertices of an affiliation network are linked to attributes and two vertices are declared adjacent whenever they share a common attribute. For example, two customers of an internet shop (or video-sharing website) are called adjacent if they have purchased (or downloaded) the same or similar items. Assuming that each newly arrived customer is linked preferentially to already popular items we obtain a preferred attachment affiliation network that evolves in time. We show that the fraction of customers having neighbours scales as for large . Here is the ratio between the two intensities: intensity of the flow of customers and that of the newly arriving items.

  1. DNA attachment to support structures

    DOEpatents

    Balhorn, Rodney L.; Barry, Christopher H.

    2002-01-01

    Microscopic beads or other structures are attached to nucleic acids (DNA) using a terminal transferase. The transferase adds labeled dideoxy nucleotide bases to the ends of linear strands of DNA. The labels, such as the antigens digoxigenin and biotin, bind to the antibody compounds or other appropriate complementary ligands, which are bound to the microscopic beads or other support structures. The method does not require the synthesis of a synthetic oligonucleotide probe. The method can be used to tag or label DNA even when the DNA has an unknown sequence, has blunt ends, or is a very large fragment (e.g., >500 kilobase pairs).

  2. Anorexia and attachment: dysregulated defense and pathological mourning

    PubMed Central

    Delvecchio, Elisa; Di Riso, Daniela; Salcuni, Silvia; Lis, Adriana; George, Carol

    2014-01-01

    The role of defensive exclusion (Deactivation and Segregated Systems) in the development of early relationships and related to subsequent manifestations of symptoms of eating disorders was assessed using the Adult Attachment Projective Picture System (AAP). Fifty-one DSM-IV diagnosed women with anorexia participated in the study. Anorexic patients were primarily classified as dismissing or unresolved. Quantitative and qualitative analyses of defensive exclusion were carried out. Results showed potential benefits of using the AAP defense exclusion coding system, in addition to the main attachment classifications, in order to better understand the developmental issues involved in anorexia. Discussion concerned the processes, such as pathological mourning, that may underlie the associations between dismissing and unresolved attachment and anorexia. Implications for developmental research and clinical nosology are discussed. PMID:25389412

  3. Conserved and divergent expression patterns of markers of axial development in reptilian embryos: Chinese soft-shell turtle and Madagascar ground gecko.

    PubMed

    Yoshida, Michio; Kajikawa, Eriko; Kurokawa, Daisuke; Noro, Miyuki; Iwai, Tatsuhiro; Yonemura, Shigenobu; Kobayashi, Kensaku; Kiyonari, Hiroshi; Aizawa, Shinichi

    2016-07-01

    The processes of development leading up to gastrulation have been markedly altered during the evolution of amniotes, and it is uncertain how the mechanisms of axis formation are conserved and diverged between mouse and chick embryos. To assess the conservation and divergence of these mechanisms, this study examined gene expression patterns during the axis formation process in Chinese soft-shell turtle and Madagascar ground gecko preovipositional embryos. The data suggest that NODAL signaling, similarly to avian embryos but in contrast to eutherian embryos, does not have a role in epiblast and hypoblast development in reptilian embryos. The posterior marginal epiblast (PME) is the initial molecular landmark of axis formation in reptilian embryos prior to primitive plate development. Ontogenetically, PME may be the precursor of the primitive plate, and phylogenetically, Koller's sickle and posterior marginal zone in avian development may have been derived from the PME. Most of the genes expressed in the mouse anterior visceral endoderm (AVE genes), especially signaling antagonist genes, are not expressed in the hypoblast of turtle and gecko embryos, though they are expressed in the avian hypoblast. This study proposes that AVE gene expression in the hypoblast and the visceral endoderm could have been independently established in avian and eutherian lineages, similar to the primitive streak that has been independently acquired in these lineages. PMID:27174471

  4. Methane production by attached film

    DOEpatents

    Jewell, William J.

    1981-01-01

    A method for purifying wastewater of biodegradable organics by converting the organics to methane and carbon dioxide gases is disclosed, characterized by the use of an anaerobic attached film expanded bed reactor for the reaction process. Dilute organic waste material is initially seeded with a heterogeneous anaerobic bacteria population including a methane-producing bacteria. The seeded organic waste material is introduced into the bottom of the expanded bed reactor which includes a particulate support media coated with a polysaccharide film. A low-velocity upward flow of the organic waste material is established through the bed during which the attached bacterial film reacts with the organic material to produce methane and carbon dioxide gases, purified water, and a small amount of residual effluent material. The residual effluent material is filtered by the film as it flows upwardly through the reactor bed. In a preferred embodiment, partially treated effluent material is recycled from the top of the bed to the bottom of the bed for further treatment. The methane and carbon dioxide gases are then separated from the residual effluent material and purified water.

  5. Attachment in romantic relationships and somatization.

    PubMed

    Neumann, Eva; Sattel, Heribert; Gündel, Harald; Henningsen, Peter; Kruse, Johannes

    2015-02-01

    Adult attachment representations have been considered to play a role in the development and treatment of somatizing behavior. In this study, the associations between the two attachment dimensions avoidance and anxiety and dimensions of psychopathology (somatization, depression, and general anxiety) were explored. The sample consists of 202 outpatients diagnosed with a somatoform disorder. Data were collected via self-report measures. A path analysis shows that the two attachment dimensions are not directly associated with somatization. There are, however, significant indirect associations between attachment and somatization mediated by depression and general anxiety, which are more pronounced for attachment anxiety than for attachment avoidance. The findings reveal that a low level of attachment security in romantic relationships, especially an anxious stance toward the partner, comes along with poor mental health, which in turn is related to a preoccupation with somatic complaints. Implications for the treatment of somatizing patients are discussed. PMID:25594785

  6. [Early attachement relationships and epigenetic customization].

    PubMed

    Rocchi, Giordana; Serio, Valentina; Carluccio, Giuseppe Mattia; Marini, Isabella; Meuti, Valentina; Zaccagni, Michela; Giacchetti, Nicoletta; Aceti, Franca

    2015-01-01

    Recently, new findings in epigenetic science switched the focus from the observation of physiological intragenomic dynamics to the idea of an environmental co-construction of phenotypic expression. In psichodynamic field, objectual relations and attachement theoreticians emphasized the interpersonal dimension of individual development, focusing the attention on the relational matrix of self organization. The construction of stable affective-behavioral traits throughout different parenting styles has actually found a coincidence in ethological studies, which have explored the epigenetic processes underlying the relationship between caregiving and HPA stress responsiveness. An adequate parenting style seems to support affective regulation throughout psychobiological hidden moderators, which would tend to rebalance the physiological systems homeostasis; an unconfident attachment style would promote, on the other hand, the allostatic load rise. Sites of longlife epigenetic susceptibility have also been identified in humans; although associated with risk of maladaptive developing in adverse environmental conditions, they seem to confer protection under favorable conditions. This persisting possibility of reorganization of stable traits throughout lifetime, which seems to be activated by a relevant environmental input, grant to significant relationships, and to therapeutical one as well, an implicit reconditioning potential which could result into the configuration of new stable affective-behavioral styles. PMID:26418595

  7. Early interpersonal neurobiological assessment of attachment and autistic spectrum disorders

    PubMed Central

    Schore, Allan N.

    2014-01-01

    There is now a strong if not urgent call in both the attachment and autism literatures for updated, research informed, clinically relevant interventions that can more effectively assess the mother infant dyad during early periods of brain plasticity. In this contribution I describe my work in regulation theory, an overarching interpersonal neurobiological model of the development, psychopathogenesis, and treatment of the early forming subjective self system. The theory models the psychoneurobiological mechanisms by which early rapid, spontaneous and thereby implicit emotionally laden attachment communications indelibly impact the experience-dependent maturation of the right brain, the “emotional brain.” Reciprocal right-lateralized visual-facial, auditory-prosodic, and tactile–gestural non-verbal communications lie at the psychobiological core of the emotional attachment bond between the infant and primary caregiver. These affective communications can in turn be interactively regulated by the primary caregiver, thereby expanding the infant’s developing right brain regulatory systems. Regulated and dysregulated bodily based communications can be assessed in order to determine the ongoing status of both the infant’s emotional and social development as well as the quality and efficiency of the infant–mother attachment relationship. I then apply the model to the assessment of early stages of autism. Developmental neurobiological research documents significant alterations of the early developing right brain in autistic infants and toddlers, as well profound attachment failures and intersubjective deficits in autistic infant–mother dyads. Throughout I offer implications of the theory for clinical assessment models. This work suggests that recent knowledge of the social and emotional functions of the early developing right brain may not only bridge the attachment and autism worlds, but facilitate more effective attachment and autism models of early

  8. Collimator with attachment mechanism and system

    DOEpatents

    Kross, Brian J.; McKisson, John; Stolin, Aleksandr; Weisenberger, Andrew G.; Zorn, Carl

    2012-07-10

    A self-aligning collimator for a radiation imaging device that is secured and aligned through the use of a plurality of small magnets. The collimator allows for the rapid exchange, removal, or addition of collimators for the radiation imaging device without the need for tools. The accompanying method discloses the use of magnets and accompanying magnetic fields to align and secure collimators in a radiation imaging assembly.

  9. The effective photoinduction of Haematococcus pluvialis for accumulating astaxanthin with attached cultivation.

    PubMed

    Wan, Minxi; Hou, Dongmei; Li, Yuanguang; Fan, Jianhua; Huang, Jianke; Liang, Songtao; Wang, Weiliang; Pan, Ronghua; Wang, Jun; Li, Shulan

    2014-07-01

    As the optimal source of astaxanthin, Haematococcus pluvialis was cultured for commercial production of astaxanthin through two continuous phases: cell growth and astaxanthin induction. In this study, the efficiency of an attached system for producing astaxanthin from H. pluvialis was investigated and compared to that of the suspended system (bubble column bioreactor) under various conditions. Results showed that this attached system is more suitable for photoinduction of H. pluvialis than the suspended bioreactor. Under the optimal conditions, the astaxanthin productivity of the attached system was 65.8 mg m(-2)d(-1) and 2.4-fold of that in the suspended system. This attached approach also offers other advantages over suspended systems, such as, producing astaxanthin under a wide range of light intensities and temperatures, saving water, ease to harvest cells, resisting contamination. Therefore, the attached approach can be considered an economical, environmentally friendly and highly-efficient technology for producing astaxanthin from H. pluvialis. PMID:24787315

  10. The evolutionary armistice: attachment bonds moderate the function of ovulatory cycle adaptations.

    PubMed

    Eastwick, Paul W; Finkel, Eli J

    2012-02-01

    Natural selection modified the attachment-behavioral system to bond adult mating partners in early members of the genus Homo, thus facilitating increased investment, especially paternal investment, in offspring. Previously existing adaptations that fostered intersexual conflict (e.g., ovulatory adaptations) could have threatened attachment bonds; therefore, the attachment-behavioral system might have evolved the ability to mute or refocus such adaptations for the purpose of strengthening the bond. Two studies offer support for this prediction. Women who were strongly attached to their romantic partner revealed positive associations of fertility with reports of romantic physical intimacy, but these associations were negative among unbonded women. This moderational effect of attachment bond strength was robust beyond dispositional attachment anxiety and avoidance, relationship satisfaction, relationship commitment, and partner physical attractiveness, none of which revealed robust moderational effects. Findings highlight how researchers can use the timeline of hominid evolution (i.e., phylogeny) as a tool to complement functional, adaptationist hypotheses. PMID:21933989

  11. Molecular evidence for ten species and Oligo-Miocene vicariance within a nominal Australian gecko species (Crenadactylus ocellatus, Diplodactylidae)

    PubMed Central

    2010-01-01

    Background Molecular studies have revealed that many putative 'species' are actually complexes of multiple morphologically conservative, but genetically divergent 'cryptic species'. In extreme cases processes such as non-adaptive diversification (speciation without divergent selection) could mask the existence of ancient lineages as divergent as ecologically and morphologically diverse radiations recognised as genera or even families in related groups. The identification of such ancient, but cryptic, lineages has important ramifications for conservation, biogeography and evolutionary biology. Herein, we use an integrated multilocus genetic dataset (allozymes, mtDNA and nuclear DNA) to test whether disjunct populations of the widespread nominal Australian gecko species Crenadactylus ocellatus include distinct evolutionary lineages (species), and to examine the timing of diversification among these populations. Results We identify at least 10 deeply divergent lineages within the single recognised species Crenadactylus ocellatus, including a radiation of five endemic to the Kimberley region of north-west Australia, and at least four known from areas of less than 100 km2. Lineages restricted to geographically isolated ranges and semi-arid areas across central and western Australia are estimated to have began to diversify in the late Oligocene/early Miocence (~20-30 mya), concurrent with, or even pre-dating, radiations of many iconic, broadly sympatric and much more species-rich Australian vertebrate families (e.g. venomous snakes, dragon lizards and kangaroos). Conclusions Instead of a single species, Crenadactylus is a surprisingly speciose and ancient vertebrate radiation. Based on their deep divergence and no evidence of recent gene flow, we recognise each of the 10 main lineages as candidate species. Molecular dating indicates that the genus includes some of the oldest vertebrate lineages confounded within a single species yet identified by molecular assessments of

  12. Eating disorders in adolescence: attachment issues from a developmental perspective

    PubMed Central

    Gander, Manuela; Sevecke, Kathrin; Buchheim, Anna

    2015-01-01

    In the present article we review findings from an emerging body of research on attachment issues in adolescents with eating disorders from a developmental perspective. Articles for inclusion in this review were identified from PsychINFO (1966–2013), Sciencedirect (1970–2013), Psychindex (1980–2013), and Pubmed (1980–2013). First, we will outline the crucial developmental changes in the attachment system and discuss how they might be related to the early onset of the disease. Then we will report on the major results from attachment studies using self-report and narrative instruments in that age group. Studies with a developmental approach on attachment will be analyzed in more detail. The high incidence of the unresolved attachment pattern in eating disorder samples is striking, especially for patients with anorexia nervosa. Interestingly, this predominance of the unresolved category was also found in their mothers. To date, these transgenerational aspects are still poorly understood and therefore represent an exciting research frontier. Future studies that include larger adolescent samples and provide a more detailed description including symptom severity and comorbidity would contribute to a better understanding of this complex and painful condition. PMID:26321974

  13. Apparatus for attaching a cleaning tool to a robotic manipulator

    DOEpatents

    Killian, Mark A.; Zollinger, W. Thor

    1992-01-01

    An apparatus for connecting a cleaning tool to a robotic manipulator so that the tool can be used in contaminated areas on horizontal, vertical and sloped surfaces. The apparatus comprises a frame and a handle, with casters on the frame to facilitate movement. The handle is pivotally and releasibly attached to the frame at a preselected position of a plurality of attachment positions. The apparatus is specifically configured for the KELLY VACUUM SYSTEM but can be modified for use with any standard mobile robot and cleaning tool.

  14. Closeup view of an External Tank (ET) Attach Ring undergoing ...

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

    Close-up view of an External Tank (ET) Attach Ring undergoing preparations in the Processing Building of the Rotation Processing and Surge Facility at Kennedy Space Center. After preparations are complete the ET Attach Ring will be mated to the top of the Aft Motor Segment. The most prominent features in this view are the ET/Solid Rocket Booster Struts in the center and left in the view and the Aft Integrated Electronics Assembly located on the right side if the ring in this view. - Space Transportation System, Solid Rocket Boosters, Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  15. Apparatus for attaching a cleaning tool to a robotic manipulator

    DOEpatents

    Killian, M.A.; Zollinger, W.T.

    1992-09-22

    An apparatus is described for connecting a cleaning tool to a robotic manipulator so that the tool can be used in contaminated areas on horizontal, vertical and sloped surfaces. The apparatus comprises a frame and a handle, with casters on the frame to facilitate movement. The handle is pivotally and releasibly attached to the frame at a preselected position of a plurality of attachment positions. The apparatus is specifically configured for the Kelly Vacuum System but can be modified for use with any standard mobile robot and cleaning tool. 14 figs.

  16. Apparatus for attaching a cleaning tool to a robotic manipulator

    DOEpatents

    Killian, M.A.; Zollinger, W.T.

    1991-01-01

    This invention is comprised of an apparatus for connecting a cleaning tool to a robotic manipulator so that the tool can be used in contaminated areas on horizontal, vertical and sloped surfaces. The apparatus comprises a frame and a handle, with casters on the frame to facilitate movement. The handle is pivotally and releasibly attached to the frame at a preselected position of a plurality of attachment positions. The apparatus is specifically configured for the KELLY VACUUM SYSTEM but can be modified for use with any standard mobile robot and cleaning tool.

  17. Temperament and attachment: one construct or two?

    PubMed

    Mangelsdorf, S C; Frosch, C A

    1999-01-01

    In this chapter we described the constructs of temperament and attachment and have discussed similarities and differences between the two. We addressed the issue of whether temperament contributes to overall attachment security or to the specific type of attachment that children display. We conclude that although temperament may influence the type of secure and insecure attachment relationship children form with their parent, temperament alone will not determine if a child is classified as securely or insecurely attached. We presented evidence suggesting that certain dimensions of temperament, specifically negative emotionality, may be associated with infants' behavior during the Strange Situation, such as proneness-to-distress during separations. However, we noted that these temperament dimensions do not predict overall security of attachment. It is likely that although no single temperament characteristic, such as proneness-to-distress, in and of itself determines overall attachment security, it is possible that a constellation of temperament characteristics may be more strongly related to attachment security. The examination of constellations of temperament characteristics may be particularly useful for furthering our understanding of individual differences within attachment classifications. Such an approach may elucidate the reasons why infants are classified into one subgroup of secure, insecure-avoidant, or insecure-resistant attachment versus another subgroup. Furthermore, we suggest that the collection of findings regarding temperament and attachment not only underscores the importance of a transactional approach to early social-emotional development, but emphasizes that temperament and attachment can make unique and interactive contributions to children's social-emotional functioning. That is, the goodness-of-fit between infant and parent characteristics may best predict security of attachment. Although child characteristics clearly contribute to the

  18. Sine-Bar Attachment For Machine Tools

    NASA Technical Reports Server (NTRS)

    Mann, Franklin D.

    1988-01-01

    Sine-bar attachment for collets, spindles, and chucks helps machinists set up quickly for precise angular cuts that require greater precision than provided by graduations of machine tools. Machinist uses attachment to index head, carriage of milling machine or lathe relative to table or turning axis of tool. Attachment accurate to 1 minute or arc depending on length of sine bar and precision of gauge blocks in setup. Attachment installs quickly and easily on almost any type of lathe or mill. Requires no special clamps or fixtures, and eliminates many trial-and-error measurements. More stable than improvised setups and not jarred out of position readily.

  19. Russian RSC Energia employees attach trunnions to DM

    NASA Technical Reports Server (NTRS)

    1995-01-01

    Employees of the Russian aerospace company RSC Energia attach trunnions to the Russian-built docking module in the Space Station Processing Facility at KSC so that it can be mounted in the payload bay of the Space Shuttle orbiter Atlantis. The module will fly as a primary payload on the second Space Shuttle/Mir space station docking mission, STS-74, which is now scheduled for liftoff in the fall of 1995. During the mission, the module will first be attached with the orbiter's robot arm to the Orbiter Docking System (ODS) in the payload bay of the orbiter Atlantis and then be docked with the Mir. When Atlantis undocks from the Mir, it will leave the new docking module permanently attached to the space station for use during future Shuttle Mir docking missions. The new module will simplify future Shuttle linkups with Mir by improving orbiter clearances when it serves as a bridge between the two space vehicles.

  20. Antecedents of maternal parenting stress: the role of attachment style, prenatal attachment, and dyadic adjustment in first-time mothers.

    PubMed

    Mazzeschi, Claudia; Pazzagli, Chiara; Radi, Giulia; Raspa, Veronica; Buratta, Livia

    2015-01-01

    The transition to parenthood is widely considered a period of increased vulnerability often accompanied by stress. Abidin conceived parenting stress as referring to specific difficulties in adjusting to the parenting role. Most studies of psychological distress arising from the demands of parenting have investigated the impact of stress on the development of dysfunctional parent-child relationships and on adult and child psychopathology. Studies have largely focused on mothers' postnatal experience; less attention has been devoted to maternal prenatal characteristics associated with subsequent parental stress and studies of maternal prenatal predictors are few. Furthermore, no studies have examined that association exclusively with samples of first-time mothers. With an observational prospective study design with two time periods, the aim of this study was to investigate the role of mothers' attachment style, maternal prenatal attachment to the fetus and dyadic adjustment during pregnancy (7th months of gestation) and their potential unique contribution to parenting stress 3 months after childbirth in a sample of nulliparous women. Results showed significant correlations between antenatal measures. Maternal attachment style (especially relationship anxiety) was negatively correlated with prenatal attachment and with dyadic adjustment; positive correlations resulted between prenatal attachment and dyadic adjustment. Each of the investigated variables was also good predictor of parenting stress 3 months after childbirth. Findings suggested how these dimensions could be considered as risk factors in the transition to motherhood and in the very beginning of the emergence of the caregiving system, especially with first-time mothers. PMID:26441808