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1

Addressable Floating Light Activated Micro-Electrical Stimulators for Wireless Neurostimulation  

E-print Network

Addressable Floating Light Activated Micro-Electrical Stimulators for Wireless Neurostimulation activate photodiodes in an array. Additionally, gene therapy technologies have enabled photonic neurostimulation in neurons that have algal proteins [10], [11]. Floating Light Activated Microelectrical

2

Feasibility of Neural Stimulation With Floating-Light-Activated Microelectrical Stimulators  

PubMed Central

Neural microstimulation is becoming a powerful tool for the restoration of impaired functions in the central nervous system. Microelectrode arrays with fine wire interconnects have traditionally been used in the development of these neural prosthetic devices. However, these interconnects are usually the most vulnerable part of the neuroprosthetic implant that can eventually cause the device to fail. In this paper, we investigate the feasibility of floating-light-activated microelectrical stimulators (FLAMES) for wireless neural stimulation. A computer model was developed to simulate the micro stimulators for typical requirements of neural activation in the human white and gray matters. First, the photon densities due to a circular laser beam were simulated in the neural tissue at near-infrared (NIR) wavelengths. Temperature elevation in the tissue was calculated and the laser power was retrospectively adjusted to 325 and 250 mW/cm2 in the gray and white matters, respectively, to limit ?T to 0.5 °C. Total device area of the FLAMES increased with all parameters considered but decreased with the output voltage. We conclude that the number of series photodiodes in the device can be used as a free parameter to minimize the device size. The results suggest that floating, optically activated stimulators are feasible at submillimeter sizes for the activation of the brain cortex or the spinal cord. PMID:21552457

Abdo, Ammar; Sahin, Mesut

2011-01-01

3

Floating Light-Activated Micro Electrical Stimulators Tested in the Rat Spinal Cord  

PubMed Central

Microelectrodes of neural stimulation utilize fine wires for electrical connections to driving electronics. Breakage of these wires and the neural tissue response due to their tethering forces are major problems encountered with long term implantation of microelectrodes. The lifetime of an implant for neural stimulation can be substantially improved if the wire interconnects are eliminated. Thus, we proposed a floating light-activated micro electrical stimulator (FLAMES) for wireless neural stimulation. In this paradigm, a laser beam at near infrared (NIR) wavelengths will be used as a means of energy transfer to the device. In this study, microstimulators of various sizes were fabricated, with two cascaded GaAs p-i-n photodiodes, and tested in the rat spinal cord. A train of NIR pulses (0.2 ms, 50 Hz) was sent through the tissue to wirelessly activate the devices and generate the stimulus current. The forces elicited by intraspinal stimulation were measured from the ipsilateral forelimb with a force transducer. The largest forces were around 1.08N, a significant level of force for the rat forelimb motor function. These in vivo tests suggest that the FLAMES can be used for intraspinal microstimulation even for the deepest implant locations in the rat spinal cord. The power required to generate a threshold arm movement was investigated as the laser source was moved away from the microstimulator. The results indicate that the photon density does not decrease substantially for horizontal displacements of the source that are in the same order as the beam radius. This gives confidence that the stimulation threshold may not be very sensitive to small displacement of the spinal cord relative to the spine-mounted optical power source. PMID:21914931

Abdo, Ammar; Sahin, Mesut; Freedman, David S.; Cevik, Elif; Spuhler, Philipp S.; Unlu, M. Selim

2011-01-01

4

In vitro testing of floating light activated micro-electrical stimulators.  

PubMed

Chronic tissue response to microelectrode implants stands in the way as a major challenge to development of many neural prosthetic applications. The long term tissue response is mostly due to the movement of interconnects and the resulting mechanical stress between the electrode and the surrounding neural tissue. Remotely activated floating micro-stimulators are one possible method of eliminating the interconnects. As a method of energy transfer to the micro-stimulator, we proposed to use a laser beam at near infrared (NIR) wavelengths. FLAMES of various sizes were fabricated with integrated silicon PIN photodiodes. Sizes varied from 120 (Width) x 300 (Length) x 100 (Height) microm to 200 x 500 x 100microm. Devices were bench tested using 850nm excitation from a Ti:Sapphire laser. To test this method, the voltage field of the FLAMES was experimentally tested in saline solution pulsed with a NIR laser beam. The voltage generated is around 196mV in peak at the cathodic contact as a response to a single pulse. When a train of laser pulses was applied at 100Hz, the peak voltage at the cathodic contact remained around 141mV suggesting the feasibility of this approach for applications with pulse frequencies up to 100Hz. PMID:19964480

Abdo, Ammar; Jayasinha, Vianney; Spuhler, Philipp S; Unlu, M; Sahin, Mesut

2009-01-01

5

Charge retention characteristics of silicide-induced crystallized polycrystalline silicon floating gate thin-film transistors for active matrix organic light-emitting diode.  

PubMed

In this work, non-volatile memory thin-film transistor (NVM-TFT) was fabricated by nickel silicide-induced laterally crystallized (SILC) polycrystalline silicon (poly-Si) as the active layer. The nickel seed silicide-induced crystallized (SIC) poly-Si was used as storage layer which is embedded in the gate insulator. The novel unit pixel of active matrix organic light-emitting diode (AMOLED) using NVM-TFT is proposed and investigated the electrical and optical performance. The threshold voltage shift showed 17.2 V and the high reliability of retention characteristic was demonstrated until 10 years. The retention time can modulate the recharge refresh time of the unit pixel of AMOLED up to 5000 sec. PMID:24245194

Park, Jae Hyo; Son, Se Wan; Byun, Chang Woo; Kim, Hyung Yoon; Joo, So Na; Lee, Yong Woo; Yun, Seung Jae; Joo, Seung Ki

2013-10-01

6

Ice Floats  

NSDL National Science Digital Library

This is a lesson about displacement, buoyancy, and density. Learners will understand why ice floats. Includes background information, teacher notes, assessment criteria, and related resources; activities are differentiated for Pre-K-grade 2 and grades 3-5. This is lesson 4 of the unit Exploring Ice in the Solar System.

7

Lighting Classroom Activity  

NSDL National Science Digital Library

In this lesson from Math Machines, students will design and test an automatic control system for lighting a room. They will examine the system's energy efficiency, response time and effectiveness. Students will be led through the activity step by step via the provided handout. A participant handout (including worksheets), facilitator notes, construction guide, sample data and annotated program listing are made available for download. Links to calculator programs are also included.

Thomas, Fred

2012-05-03

8

"Does it Float?" An inquiry-based activity investigating buoyancy  

NSDL National Science Digital Library

This is an inquiry-based activity in which students will need to work together as a class to solve the following problem: they must construct a "boat" entirely out of modeling clay that is capable of supporting 150 grams of cargo without sinking.

Sletten, Sean

9

33 CFR 149.550 - What are the requirements for lights on a floating hose string?  

Code of Federal Regulations, 2011 CFR

...6) Not more than 10 meters (32.8 feet) apart...course. (b) Two red lights at each end of the...open or closed. The lights must be: (1) Visible...night; and (3) One meter (3 feet) apart in a vertical line with the lower light at the same height...

2011-07-01

10

Light-Induced Carrier Transfer in NiSi-Nanodots/Si-Quantum-Dots Hybrid Floating Gate in Metal-Oxide-Semiconductor Structures  

NASA Astrophysics Data System (ADS)

We have fabricated a metal-oxide-semiconductor (MOS) capacitor with a hybrid floating gate stack consisting of silicon quantum dots (Si-QDs) and NiSi Nanodots (NiSi-NDs) with a 3-nm-thick interlayer SiO2, and studied the effect of 1310 nm light irradiation on charge distribution in a hybrid floating gate. The light irradiation resulted in a reduced flat-band voltage shift due to the charging of the hybrid floating gate under the application of gate biases in comparison to the shift in the dark. This result can be interpreted in terms of the shift of the charge centroid toward the gate side in the hybrid floating gate caused by the photoexcitation of electrons in NiSi-NDs and the subsequent electron tunneling to Si-QDs. When the light irradiation was turned off, the transferred charges moved back from the Si-QDs to the NiSi-NDs without being emitted to the Si substrate.

Naoya Morisawa,; Mitsuhisa Ikeda,; Sho Nakanishi,; Akira Kawanami,; Katsunori Makihara,; Seiichi Miyazaki,

2010-04-01

11

Light and flotsam-dependent ‘float-and-wait’ foraging by pelagic sea snakes ( Pelamis platurus )  

Microsoft Academic Search

Efficient detection of food patches in oceanic areas by pelagic predators is often linked to large-scale physical structures\\u000a (e.g. fronts, upwellings) that are usually rich and predictable. At smaller scales, however, predictability of resource becomes\\u000a less clear because of the lability of smaller physical structures such as slicks and drift lines. Here, we explore how light\\u000a levels and quantity of

François Brischoux; Harvey B. Lillywhite

12

What Makes a Boat Float?  

NSDL National Science Digital Library

Whether or not a boat floats is determined by its shape and density. In this activity, students discover how and why boats float by designing different hull shapes and finding which design holds the most weight. Students record, calculate, and interpret data as they learn about buoyancy in this hands-on activity.

Eichinger, John

2009-05-01

13

Ultraviolet light and ultraviolet light-activated composite resins  

SciTech Connect

In a comparison of the UV light--activated composite resins, Estilux was polymerized to a significantly greater depth than the other composite resins. In general, Lee-fill polymerized the least. When comparing the UV light sources, the Lee light and the Duralux light did not significantly differ from each other, but both polymerized the materials tested to a significantly greater depth than the other light sources. Of the two time exposures, 60-second exposure provided a significantly greater depth of polymerization than 20 seconds for each light with each material.

Murray, G.A.; Yates, J.L.; Newman, S.M.

1981-08-01

14

Intracellular light-activation of riboswitch activity.  

PubMed

By combining a riboswitch with a cell-permeable photocaged small-molecule ligand, an optochemical gene control element was constructed that enabled spatial and temporal control of gene expression in bacterial cells. The simplicity of this strategy, coupled with the ability to create synthetic riboswitches with tailored ligand specificities and output in a variety of microorganisms, plants, and fungi might afford a general strategy to photocontrol gene expression in vivo. The ability to activate riboswitches by using light enables the interrogation and manipulation of a wide range of biological processes with high precision, and will have broad utility in the regulation of artificial genetic circuits. PMID:24861567

Walsh, Steven; Gardner, Laura; Deiters, Alexander; Williams, Gavin J

2014-06-16

15

Float My Boat  

NSDL National Science Digital Library

In this activity, learners use tinfoil to build and test their own boats - which designs will float, and which will sink? Learners must adjust many variables in their boat design to maximize stability and flotation, in order for the boat to support a heavy load of pennies. This activity is great used with lessons on engineering or design.

Wgbh

2006-01-01

16

Floating Paper Clip  

NSDL National Science Digital Library

In this activity, challenge learners to float a paper clip in a cup of water. Learners discover that a paper clip will sink in a cup of water, except when it is placed on a piece of paper towel. Use this activity to demonstrate the principles of surface tension, adhesion/cohesion, and gravity.

Boston, Wgbh

2002-01-01

17

On floats and float tests  

NASA Technical Reports Server (NTRS)

The principal source of information on float resistance is the model test. In view of the insuperable difficulties opposing any attempt at theoretical treatment of the resistance problem, particularly at attitudes which tend toward satisfactory take-off, such as the transitory stage to planing, the towing test is and will remain the primary method for some time.

Seewald, Friedrich

1931-01-01

18

Lighting Class Activity: Web Search  

NSDL National Science Digital Library

This class exercise asks students to use the web to search for lighting resources. Students are asked to find resources that focus on both traditional and green lighting technologies. They will then write a one page report on what they found and the best features of their favorite sites. This assignment would be most useful in a high school or lower college level residential design course. This document may be downloaded in Microsoft Word Doc file format.

Wolf, Arlynne

2012-01-03

19

Artificial light and nocturnal activity in gammarids.  

PubMed

Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month's exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One flume was exposed to strong (416 lx) artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift. PMID:24688857

Perkin, Elizabeth K; Hölker, Franz; Heller, Stefan; Berghahn, Rüdiger

2014-01-01

20

Artificial light and nocturnal activity in gammarids  

PubMed Central

Artificial light is gaining attention as a potential stressor to aquatic ecosystems. Artificial lights located near streams increase light levels experienced by stream invertebrates and we hypothesized light would depress night drift rates. We also hypothesized that the effect of light on drift rates would decrease over time as the invertebrates acclimated to the new light level over the course of one month’s exposure. These hypotheses were tested by placing Gammarus spp. in eight, 75 m × 1 m artificial flumes. One flume was exposed to strong (416 lx) artificial light at night. This strong light created a gradient between 4.19 and 0.04 lx over the neighboring six artificial flumes, while a control flume was completely covered with black plastic at night. Night-time light measurements taken in the Berlin area confirm that half the flumes were at light levels experienced by urban aquatic invertebrates. Surprisingly, no light treatment affected gammarid drift rates. In contrast, physical activity measurements of in situ individually caged G. roeseli showed they increased short-term activity levels in nights of complete darkness and decreased activity levels in brightly lit flumes. Both nocturnal and diurnal drift increased, and day drift rates were unexpectadly higher than nocturnal drift. PMID:24688857

Holker, Franz; Heller, Stefan; Berghahn, Rudiger

2014-01-01

21

Mechanics of light-activated network polymers  

NASA Astrophysics Data System (ADS)

Mechanically responsive, environmentally activated polymers can undergo large, complex deformation in response to external stimuli such as thermal, luminous, and chemical changes to the environment. Light as a stimulus provides unique application potential because it allows for remote, rapid, and isothermal activation of the material with precise spatial control via existing optical technologies. While certain systems have received considerable attention, the state of the art of most light-activated polymers is limited to basic characterization and demonstrations. To make such materials available to the engineering and scientific communities, physically based theoretical and computational tools are required to guide experimental and design efforts that capitalize on their complex photo-mechanical couplings. The central objective of this thesis is to develop a multi-physics constitutive modeling framework to simulate the continuum scale, photo mechanical behavior of light-activated polymers and implement it into a finite element analysis setting. This framework is independent of specific underlying photo-stimulation mechanisms and is discussed in the context of photo-activated shape memory polymers and network rearranging polymers. Next, the framework is applied to the light-activated network rearranging polymer system, which is relaxed of stress upon irradiation with UV light, and a suite of characterization and application oriented experiments are carried out to calibrate and validate the model's predictive capabilities. The calibrated model is used to investigate several applications such as photo-activated stress relaxation of notched specimens, bending actuation, creep, the buckling of equi-biaxially deformed and irradiated films, and photomechanically formed 1D channels and ridges. Modeling creep involves additional complexity through simultaneous deformation and irradiation, and so the model framework is extended to cover such scenarios. Experiments, finite element analyses, and analytic solutions are developed to explore the phase space available to the experimentalist and design engineer for these different problems.

Long, Kevin Nicholas

22

Suminagashi: Floating Ink Paper Marbling  

NSDL National Science Digital Library

In this activity, learners try to float ink on the surface of water to create a pattern and then capture it with absorbent paper. This technique, called Suminagashi, is an ancient Japanese style of decorating paper with inks and believed to be the oldest form of marbling. This art activity can introduce learners to fluid mechanics, viscosity, and surface tension.

Henricks, Jessica

2012-06-26

23

Will It Float?  

NSDL National Science Digital Library

Student preconceptions are one of the greatest challenges we face as science teachers. This Predict, Explain, Observe, and Explain (PEOE) activity challenges students? preconceived notions about why matter floats or sinks when placed in a liquid. The idea behind this model is to do a demonstration that first confirms student's conceptions followed by a second, similar demonstration that provides discrepant information creating cognitive dissonance. Learning happens as students are forced to modify their conceptions so that their view of how things work is not in conflict with what they are seeing.

Major, Jeff

2006-01-01

24

Potato Float  

NSDL National Science Digital Library

This is a hands-on lab activity about seawater density, specifically the relationship between density of fluid, weight of an object, and buoyancy. Learners will develop hypotheses and observe a demonstration of density to understand its role in buoyancy. They will also examine the effect of salinity on density. Background information, common preconceptions, a glossary and more is included. This activity is part of the Aquarius Hands-on Laboratory Activities.

25

Floating sample-collection platform with stage-activated automatic water sampler for streams with large variation in stage  

USGS Publications Warehouse

A floating sample-collection platform is described for stream sites where the vertical or horizontal distance between the stream-sampling point and a safe location for the sampler exceed the suction head of the sampler. The platform allows continuous water sampling over the entire storm-runoff hydrogrpah. The platform was developed for a site in southern Illinois.

Tarte, Stephen R.; Schmidt, A.R.; Sullivan, Daniel J.

1992-01-01

26

Floating Candles  

NSDL National Science Digital Library

In this chemistry activity, learners observe a combustion reaction and deduce the components necessary for the reaction to occur. They will also see the relationship between pressure, volume, and number of molecules for gasses. This activity, which can also be conducted as a demonstration, illustrates Charles's Law and Boyle's Law.

House, The S.

2014-01-28

27

Light Activated Self-Propelled Colloids  

E-print Network

Light-activated self-propelled colloids are synthesized and their active motion is studied using optical microscopy. We propose a versatile route using different photoactive materials, and demonstrate a multiwavelength activation and propulsion. Thanks to the photoelectrochemical properties of two semiconductor materials (\\alpha Fe2 O3 and TiO2 ), a light with an energy higher than the bandgap triggers the reaction of decomposition of hydrogen peroxide and produces a chemical cloud around the particle. It induces a phoretic attraction with neighbouring colloids as well as an osmotic self- propulsion of the particle on the substrate. We use these mechanisms to form colloidal cargos as well as self-propelled particles where the light-activated component is embedded into a dielectric sphere. The particles are self-propelled along a direction otherwise randomized by thermal fluctuations, and exhibit a persistent random walk. For sufficient surface density, the particles spontaneously form "living crystals" which are mobile, break apart and reform. Steering the particle with an external magnetic field, we show that the formation of the dense phase results from the collisions heads-on of the particles. This effect is intrinsically non-equilibrium and a novel principle of organization for systems without detailed balance. Engineering families of particles self-propelled by different wavelength demonstrate a good understanding of both the physics and the chemistry behind the system and points to a general route for designing new families of self-propelled particles.

J. Palacci; S. Sacanna; S. -H. Kim; G. -R. Yi; D. J. Pine; P. M. Chaikin

2014-10-27

28

Light-Dependent Electrogenic Activity of Cyanobacteria  

PubMed Central

Background Cyanobacteria account for 20–30% of Earth's primary photosynthetic productivity and convert solar energy into biomass-stored chemical energy at the rate of ?450 TW [1]. These single-cell microorganisms are resilient predecessors of all higher oxygenic phototrophs and can be found in self-sustaining, nitrogen-fixing communities the world over, from Antarctic glaciers to the Sahara desert [2]. Methodology/Principal Findings Here we show that diverse genera of cyanobacteria including biofilm-forming and pelagic strains have a conserved light-dependent electrogenic activity, i.e. the ability to transfer electrons to their surroundings in response to illumination. Naturally-growing biofilm-forming photosynthetic consortia also displayed light-dependent electrogenic activity, demonstrating that this phenomenon is not limited to individual cultures. Treatment with site-specific inhibitors revealed the electrons originate at the photosynthetic electron transfer chain (P-ETC). Moreover, electrogenic activity was observed upon illumination only with blue or red but not green light confirming that P-ETC is the source of electrons. The yield of electrons harvested by extracellular electron acceptor to photons available for photosynthesis ranged from 0.05% to 0.3%, although the efficiency of electron harvesting likely varies depending on terminal electron acceptor. Conclusions/Significance The current study illustrates that cyanobacterial electrogenic activity is an important microbiological conduit of solar energy into the biosphere. The mechanism responsible for electrogenic activity in cyanobacteria appears to be fundamentally different from the one exploited in previously discovered electrogenic bacteria, such as Geobacter, where electrons are derived from oxidation of organic compounds and transported via a respiratory electron transfer chain (R-ETC) [3], [4]. The electrogenic pathway of cyanobacteria might be exploited to develop light-sensitive devices or future technologies that convert solar energy into limited amounts of electricity in a self-sustainable, CO2-free manner. PMID:20520829

Baskakov, Ilia V.

2010-01-01

29

Anomalous Light Phenomena vs. Bioelectric Brain Activity  

NASA Astrophysics Data System (ADS)

We present a research proposal concerning the instrumented investigation of anomalous light phenomena that are apparently correlated with particular mind states, such as prayer, meditation or psi. Previous research by these authors demonstrate that such light phenomena can be monitored and measured quite efficiently in areas of the world where they are reported in a recurrent way. Instruments such as optical equipment for photography and spectroscopy, VLF spectrometers, magnetometers, radar and IR viewers were deployed and used massively in several areas of the world. Results allowed us to develop physical models concerning the structural and time-variable behaviour of light phenomena, and their kinematics. Recent insights and witnesses have suggested to us that a sort of "synchronous connection" seems to exist between plasma-like phenomena and particular mind states of experiencers who seem to trigger a light manifestation which is very similar to the one previously investigated. The main goal of these authors is now aimed at the search for a concrete "entanglement-like effect" between the experiencer's mind and the light phenomena, in such a way that both aspects are intended to be monitored and measured simultaneously using appropriate instrumentation. The goal of this research project is twofold: a) to verify quantitatively the existence of one very particular kind of mind-matter interaction and to study in real time its physical and biophysical manifestations; b) to repeat the same kind of experiment using the same test-subject in different locations and under various conditions of geomagnetic activity.

Teodorani, M.; Nobili, G.

30

Thermal light variations of active galactic nuclei  

NASA Technical Reports Server (NTRS)

Thermal limit cycles in accretion disks are a promising explanation of the quasi-periodic outbursts of dwarf novae. A similar mechanism may lead to observable light variations in active galactic nuclei (AGNs) at wavelengths 1-5 microns. The variations should obey a characteristic period-luminosity relation. For low-luminosity AGNs, these variations could have a period of less than about 10 yr.

Clarke, C. J.; Shields, G. A.

1989-01-01

31

Antibacterial nanofiber materials activated by light.  

PubMed

Electrospun polymeric nanofiber materials doped with 5,10,15,20-tetraphenylporphyrin (TPP) photosensitizer were prepared from four different polymers and were characterized with microscopic methods, steady-state, and time-resolved fluorescence and absorption spectroscopy. The polymers used included polyurethane Larithane™ (PUR), polystyrene (PS), polycaprolactone (PCL), and polyamide 6 (PA6). The antibacterial activity of all nanofiber materials against E. coli was activated by visible light and it was dependent on oxygen permeability/diffusion coefficients and the diameter of the polymeric nanofibers. This activity is based on oxidation ability of singlet oxygen O?(¹?(g)) that is generated upon irradiation. All tested nanofiber materials exhibited prolonged antibacterial properties, even in the dark after long-duration irradiation. The post-irradiation effect was explained by the photogeneration of H?O?, which provided the material with long-lasting antibacterial properties. PMID:21972201

Jesenská, So?a; Plíštil, Lukáš; Kubát, Pavel; Lang, Kamil; Brožová, Libuše; Popelka, St?pán; Szatmáry, Lórant; Mosinger, Ji?í

2011-12-15

32

Active Brownian motion tunable by light.  

PubMed

Active Brownian particles are capable of taking up energy from their environment and converting it into directed motion; examples range from chemotactic cells and bacteria to artificial micro-swimmers. We have recently demonstrated that Janus particles, i.e. gold-capped colloidal spheres, suspended in a critical binary liquid mixture perform active Brownian motion when illuminated by light. In this paper, we investigate in more detail their swimming mechanism, leading to active Brownian motion. We show that the illumination-borne heating induces a local asymmetric demixing of the binary mixture, generating a spatial chemical concentration gradient which is responsible for the particle's self-diffusiophoretic motion. We study this effect as a function of the functionalization of the gold cap, the particle size and the illumination intensity: the functionalization determines what component of the binary mixture is preferentially adsorbed at the cap and the swimming direction (towards or away from the cap); the particle size determines the rotational diffusion and, therefore, the random reorientation of the particle; and the intensity tunes the strength of the heating and, therefore, of the motion. Finally, we harness this dependence of the swimming strength on the illumination intensity to investigate the behavior of a micro-swimmer in a spatial light gradient, where its swimming properties are space-dependent. PMID:22739052

Buttinoni, Ivo; Volpe, Giovanni; Kümmel, Felix; Volpe, Giorgio; Bechinger, Clemens

2012-07-18

33

Active Brownian Motion Tunable by Light  

E-print Network

Active Brownian particles are capable of taking up energy from their environment and converting it into directed motion; examples range from chemotactic cells and bacteria to artificial micro-swimmers. We have recently demonstrated that Janus particles, i.e. gold-capped colloidal spheres, suspended in a critical binary liquid mixture perform active Brownian motion when illuminated by light. In this article, we investigate in some more details their swimming mechanism leading to active Brownian motion. We show that the illumination-borne heating induces a local asymmetric demixing of the binary mixture generating a spatial chemical concentration gradient, which is responsible for the particle's self-diffusiophoretic motion. We study this effect as a function of the functionalization of the gold cap, the particle size and the illumination intensity: the functionalization determines what component of the binary mixture is preferentially adsorbed at the cap and the swimming direction (towards or away from the cap); the particle size determines the rotational diffusion and, therefore, the random reorientation of the particle; and the intensity tunes the strength of the heating and, therefore, of the motion. Finally, we harness this dependence of the swimming strength on the illumination intensity to investigate the behaviour of a micro-swimmer in a spatial light gradient, where its swimming properties are space-dependent.

Ivo Buttinoni; Giovanni Volpe; Felix Kümmel; Giorgio Volpe; Clemens Bechinger

2011-10-10

34

Float Zone Workshop  

NASA Technical Reports Server (NTRS)

A summary of the Analytical Float Zone Experiment System (AFZES) concept is presented. The types of experiments considered for such a facility are discussed. Reports from various industrial producers and users of float zone material are presented. Special emphasis is placed on state-of-the-art developments in low gravity manufacturing and their applications to space processing.

Naumann, R. J.

1980-01-01

35

Floating emitter solar cell  

NASA Technical Reports Server (NTRS)

A front surface contact floating emitter solar cell transistor is provided in a semiconductor body (n-type), in which floating emitter sections (p-type) are diffused or implanted in the front surface. Between the emitter sections, a further section is diffused or implanted in the front surface, but isolated from the floating emitter sections, for use either as a base contact to the n-type semiconductor body, in which case the section is doped n+, or as a collector for the adjacent emitter sections.

Chih, Sah (inventor); Cheng, Li-Jen (inventor)

1987-01-01

36

National Synchrotron Light Source 2010 Activity Report  

SciTech Connect

This is a very exciting period for photon sciences at Brookhaven National Laboratory. It is also a time of unprecedented growth for the Photon Sciences Directorate, which operates the National Synchrotron Light Source (NSLS) and is constructing NSLS-II, both funded by the Department of Energy's Office of Science. Reflecting the quick pace of our activities, we chose the theme 'Discovery at Light Speed' for the directorate's 2010 annual report, a fiscal year bookended by October 2009 and September 2010. The year began with the news that NSLS users Venki Ramakrishnan of Cambridge University (also a former employee in Brookhaven's biology department) and Thomas A. Steitz of Yale University were sharing the 2009 Nobel Prize in Chemistry with Ada E. Yonath of the Weizmann Institute of Science. Every research project has the potential for accolades. In 2010, NSLS users and staff published close to 900 papers, with about 170 appearing in premiere journals. Those are impressive stats for a facility nearly three decades old, testament to the highly dedicated team keeping NSLS at peak performance and the high quality of its user community. Our NSLS users come from a worldwide community of scientists using photons, or light, to carry out research in energy and environmental sciences, physics, materials science, chemistry, biology and medicine. All are looking forward to the new capabilities enabled by NSLS-II, which will offer unprecedented resolution at the nanoscale. The new facility will produce x-rays more than 10,000 times brighter than the current NSLS and host a suite of sophisticated instruments for cutting-edge science. Some of the scientific discoveries we anticipate at NSLS-II will lead to major advances in alternative energy technologies, such as hydrogen and solar. These discoveries could pave the way to: (1) catalysts that split water with sunlight for hydrogen production; (2) materials that can reversibly store large quantities of electricity or hydrogen; (3) high-temperature superconducting materials that carry electricity with no loss for efficient power transmission lines; and (4) materials for solid-state lighting with half of the present power consumption. Excitement about NSLS-II is evident in many ways, most notably the extraordinary response we had to the 2010 call for beamline development proposals for the anticipated 60 or more beamlines that NSLS-II will ultimately host. A total of 54 proposals were submitted and, after extensive review, 34 were approved. Funding from both the Department of Energy and the National Institutes of Health has already been secured to support the design and construction of a number of these beamlines. FY11 is a challenging and exciting year for the NSLS-II Project as we reach the peak of our construction activity. We remain on track to complete the project by March 2014, a full 15 months ahead of schedule and with even more capabilities than originally planned. The Photon Sciences Directorate is well on its way to fulfilling our vision of being a provider of choice for world-class photon sciences and facilities.

Rowe, M.; Snyder, K. J.

2010-12-29

37

Light-Triggered Myosin Activation for Probing Dynamic Cellular Processes  

E-print Network

Shining light on myosin: The incorporation of a caging group onto the essential phosphoserine residue of myosin by protein semisynthesis enables light-triggered activation of the protein (see picture). Caging eliminates ...

Goguen, Brenda N.

38

A floating type holographic display.  

PubMed

A floating image type holographic display which projects an electronically generated holographic image together with a background image displayed on a monitor/TV to enhance the visual effects of the former image is introduced. This display can display a holographic image with a spatial volume floating in the front space of the display with use of PDLC sheets as the focused plane of the image. This display can preserve and enhance the main property of holographic image from a display chip, i.e., a spatial image with a volume. This property had not been appealed by the previous holographic displays due to the much brighter active surface image accompanied with the reconstructed image and the diffuser used for viewing the image. PMID:24105588

Son, Jung-Young; Lee, Chun-Hae; Chernyshov, Oleksii O; Lee, Beom-Ryeol; Kim, Sung-Kyu

2013-08-26

39

Micromechanisms with floating pivot  

DOEpatents

A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use floating pivot structures to relieve some of the problems encountered in the use of solid flexible pivots.

Garcia, Ernest J. (Albuquerque, NM)

2001-03-06

40

Floating Magnet Demonstration.  

ERIC Educational Resources Information Center

A room-temperature demonstration of a floating magnet using a high-temperature superconductor is described. The setup and operation of the apparatus are described. The technical details of the effect are discussed. (CW)

Wake, Masayoshi

1990-01-01

41

National Synchrotron Light Source 2008 Activity Report  

Microsoft Academic Search

Funded by the U.S. Department of Energy's Office of Basic Energy Sciences, the National Synchrotron Light Source (NSLS) is a national user facility that operates two electron storage rings: X-Ray (2.8 GeV, 300 mA) and Vacuum Ultraviolet (VUV) (800 mev, 1.0A). These two rings provide intense light spanning the electromagnetic spectrum -- from very long infrared rays to ultraviolet light

Nasta

2009-01-01

42

Ultraviolet B light stimulates hornet activities - a review  

Microsoft Academic Search

For more than 30 years now, we have been gathering data on vespan activity in the field and laboratory under the influence of various factors. We found that light is most influential on the behaviour and activities of hornets (Hymenoptera, Vespinae); among various light wavelengths, the greatest influence was ascribed to the ultraviolet bandwidth (UVB). Prominent vespan activities outside their

Jacob S. Ishay; Shira Kirshboim

2000-01-01

43

Lighting and Electrical Plan Class Activity  

NSDL National Science Digital Library

This class exercise asks students to complete a lighting and electrical plan for a building in the most energy efficient approach possible. They will be given a floor plan to work with, and will then determine which outlets, types of lighting and switches to use. This document may be downloaded in Microsoft Word Doc file format.

Wolf, Arlynne

2011-12-06

44

Floating wind turbine system  

NASA Technical Reports Server (NTRS)

A floating wind turbine system with a tower structure that includes at least one stability arm extending therefrom and that is anchored to the sea floor with a rotatable position retention device that facilitates deep water installations. Variable buoyancy for the wind turbine system is provided by buoyancy chambers that are integral to the tower itself as well as the stability arm. Pumps are included for adjusting the buoyancy as an aid in system transport, installation, repair and removal. The wind turbine rotor is located downwind of the tower structure to allow the wind turbine to follow the wind direction without an active yaw drive system. The support tower and stability arm structure is designed to balance tension in the tether with buoyancy, gravity and wind forces in such a way that the top of the support tower leans downwind, providing a large clearance between the support tower and the rotor blade tips. This large clearance facilitates the use of articulated rotor hubs to reduced damaging structural dynamic loads. Major components of the turbine can be assembled at the shore and transported to an offshore installation site.

Viterna, Larry A. (Inventor)

2009-01-01

45

Active switching in metamaterials using polarization control of light  

E-print Network

We demonstrate on-demand control of localized surface plasmons in metamaterials by means of incident light polarization. An asymmetric mode, selectively excited by s-polarized light, interfere destructively with a bright element, thereby allowing the incident light to propagate at a fairly low loss, corresponding to electromagnetically induced transparency (EIT) in an atomic system. In contrast, a symmetric mode, excited by p-polarized light, directly couples with the incident light, which is analogous to the switch-off of EIT. The light polarization-dependent excitation of asymmetric and symmetric plasmon modes holds potential for active switching applications of plasmon hybridization.

Hua Xu; Byoung Seung Ham

2010-10-11

46

Advanced Light Source Activity Report 2002  

SciTech Connect

This annual report of the Advanced Light Source details science highlights and facility improvements during the year. It also offers information on events sponsored by the facility, technical specifications, and staff and publication information.

Duque, Theresa; Greiner, Annette; Moxon, Elizabeth; Robinson, Arthur; Tamura, Lori (Editors)

2003-06-12

47

Light active and sterile neutrinos from compositeness  

NASA Astrophysics Data System (ADS)

Neutrinos can have naturally small Dirac masses if the Standard Model singlet right-handed neutrinos are light composite fermions. Theories which produce light composite fermions typically generate many of them, three of which can marry the left-handed neutrinos with small Dirac masses. The rest can serve as sterile states which can mix with the Standard Model neutrinos. We present explicit models illustrating this idea.

Arkani-Hamed, Nima; Grossman, Yuval

1999-07-01

48

Optical activity in the scattering of structured light.  

PubMed

We observe that optical activity in light scattering can be probed using types of illuminating light other than single plane (or quasi plane) waves and that this introduces new possibilities for the study of molecules and atoms. We demonstrate this explicitly for natural Rayleigh optical activity which, we suggest, could be exploited as a new form of spectroscopy for chiral molecules through the use of illuminating light comprised of two plane waves that are counter propagating. PMID:25315363

Cameron, Robert P; Barnett, Stephen M

2014-12-21

49

What Floats Your Boat?  

NSDL National Science Digital Library

Students use modeling clay, a material that is denser than water and thus ordinarily sinks in water, to discover the principle of buoyancy. They begin by designing and building boats out of clay that will float in water, and then refine their designs so that their boats will carry as great a load (metal washers) as possible. Building a clay boat to hold as much weight as possible is an engineering design problem. Next, they compare amount of water displaced by a lump of clay that sinks to the amount of water displaced by the same lump of clay when it is shaped so as to float. Determining the masses of the displaced water allows them to arrive at Archimedes' principle, whereby the mass of the displaced water equals the mass of the floating clay boat.

Engineering K-Phd Program

50

Blue light-activated hypocrellin B damages ovarian cancer cells  

NASA Astrophysics Data System (ADS)

In the present study, a novel blue light source from LED was used to activate hypocrellin B in ovarian cancer HO-8910 cells. Hyppcrellin B concentration was kept at 2.5 ?M and light doses from 0.5-4.0 J/cm2. Photocytotoxicity was investigated using MTT reduction assay and light microscopy after light irradiation. Cellular morphology was observed using transmission electron microscopy (TEM). MTT assay showed that the cytotoxicity of blue light-activated hypocrellin B in HO-8910 cells increased along with light dose. The observations from light microscopy reinforced the above results. TEM showed that microvillin disappearance, vacuole formation, chromatin condensation, and topical apoptotic body were observed in the cells treated by both light and hypocrellin B. The findings demonstrated that blue light from LED source could effectively activate hypocrellin B to cause the destruction of HO-8910 cells, indicating that Blue light-activated hypocrellin B might be potential therapeutic strategy in the management of ovarian cancer.

Jiang, Y.; Leung, A. W. N.; Xiang, J. Y.; Xu, C. S.

2011-10-01

51

Floating--A Key to Survival.  

ERIC Educational Resources Information Center

Described are several activities to be used to help students grasp the concept of floating. The activities include the use of a spring scale to measure the weight of the objects in air, in water, and in salt water, and a discussion of why there are differences in these weights. (DS)

Anderson, Norman

1980-01-01

52

Can flexibility help you float?  

E-print Network

We consider the role of flexibility in the weight-bearing characteristics of bodies floating at an interface. Specifically, we develop a theoretical model for a two-dimensional thin floating plate that yields the maximum ...

Burton, Lisa Janelle

53

NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 1998.  

SciTech Connect

In FY 1998, following the 50th Anniversary Year of Brookhaven National Laboratory, Brookhaven Science Associates became the new Managers of BNL. The new start is an appropriate time to take stock of past achievements and to renew or confirm future goals. During the 1998 NSLS Annual Users Meeting (described in Part 3 of this Activity Report), the DOE Laboratory Operations Board, Chaired by the Under Secretary for Energy, Ernest Moniz met at BNL. By chance all the NSLS Chairmen except Martin Blume (acting NSLS Chair 84-85) were present as recorded in the picture. Under their leadership the NSLS has improved dramatically: (1) The VUV Ring current has increased from 100 mA in October 1982 to nearly 1 A today. For the following few years 10 Ahrs of current were delivered most weeks - NSLS now exceeds that every day. (2) When the first experiments were performed on the X-ray ring during FY1985 the electron energy was 2 GeV and the current up to 100 mA - the X-Ray Ring now runs routinely at 2.5 GeV and at 2.8 GeV with up to 350 mA of current, with a very much longer beam half-life and improved reliability. (3) Starting in FY 1984 the proposal for the Phase II upgrade, mainly for a building extension and a suite of insertion devices and their associated beamlines, was pursued - the promises were delivered in full so that for some years now the NSLS has been running with two undulators in the VUV Ring and three wigglers and an undulator in the X-Ray Ring. In addition two novel insertion devices have been commissioned in the X13 straight. (4) At the start of FY 1998 the NSLS welcomed its 7000th user - attracted by the opportunity for pursuing research with high quality beams, guaranteed not to be interrupted by 'delivery failures', and welcomed by an efficient and caring user office and first class teams of PRT and NSLS staff. R & D have lead to the possibility of running the X-Ray Ring at the higher energy of 2.8 GeV. Figure 1 shows the first user beam, which was provided thereafter for half of the running time in FY 1998. In combination with the development of narrow gap undulators this mode opens the possibility of new undulators which could produce hard X-rays in the fundamental, perhaps up to 10 keV. On 27 September 1998, a low horizontal emittance lattice became operational at 2.584 GeV. This results in approximately a 50% decrease in the horizontal beam-size on dipole bending magnet beamlines, and somewhat less of a decrease on the insertion device lines. The beam lifetime is not degraded by the low emittance lattice. This represents an important achievement, enhancing for all users the x-ray ring brightness. The reduced horizontal emittance electron beam will produce brighter x-ray beams for all the beamlines, both bending magnets and insertion devices, adding to other recent increases in the X-Ray ring brightness. During FY 1999 users will gain experience of the new running mode and plans are in place to do the same at 2.8GeV during further studies sessions. Independent evidence of the reduced emittance is shown in Figure 2. This is a pinhole camera scan showing the X-ray beam profile, obtained on the diagnostic beamline X28. Finally, work has begun to update and refine the proposal of the Phase III upgrade endorsed by the Birgeneau panel and BESAC last year. With the whole NSLS facility in teenage years and with many demonstrated enhancements available, the time has come to herald in the next stage of life at the Light Source.

ROTHMAN,E.

1999-05-01

54

Floating debris in rivers and lakes in Serbia  

Microsoft Academic Search

An analysis of floating debris is conducted. It was found that components of debris is similar to the municipal waste and consists of plastic bags, bottles and glasses, tires, dead branches and tree trunks, aluminium waste, mud, etc. Floating debris cause pollution of water bodies and disturb activities related to the use and regulation of water recourses. It is suggested

Danica Zupanski

55

Corona from floating electrodes  

Microsoft Academic Search

It is not unusual to have insulated conducting objects located close to the conductors of a Lightning Protection System. However, the separation of these objects from the Lightning Protection System could vary from a few millimetres to some centimetres. When the system is exposed to thunderstorm electric fields, discharge could be initiated between the Lightning Protection System and the floating

Francisco Roman; Vernon Cooray; Viktor Scuka

1996-01-01

56

Compound floating pivot micromechanisms  

DOEpatents

A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

Garcia, Ernest J. (Albuquerque, NM)

2001-04-24

57

Light Stimulation of Active Transport in Hydrodictyon africanum  

PubMed Central

The mechanism of light stimulation of active K and Cl influx and active Na efflux, in Hydrodictyon africanum has been investigated using different wavelengths of red light and different gas mixtures, and the inhibitors DCMU and CCCP. The active Cl influx requires photosystem 2, since its relative quantal efficiency falls with increasing wavelength of red light, and it is as sensitive to the inhibitor DCMU as is photosynthesis; it is relatively insensitive to the uncoupler CCCP. The active K influx and active Na efflux are inhibited by CCCP, but the relative quantal efficiency of these processes increases with increasing wavelength of red light, and they are relatively insensitive to DCMU. These cation fluxes can be supported by cyclic photophosphorylation, whereas Cl influx needs photosystem 2 but probably not ATP. PMID:6034761

Raven, J. A.

1967-01-01

58

Floating platform with monolithically formed float members and platform  

SciTech Connect

Floating platforms for various offshore facilities are formed of float members monolithically connected to a superposed platform. The float members are spherically shaped and are formed of reinforced or prestressed concrete. The platform can be a hollow planar member or it can be curved in one or two directions, and the platforms are formed of prestressed concrete. Cylindrical shafts can be used to connect the spherically shaped floats and the platform. Individual floating platforms can be connected by expansion joints and used as a runway. The float members can be constructed at the shoreline, launched into the water and held in a regular pattern while decked over with the platform. After completion of the construction procedure, the floating platform can be moved to an offshore location for use.

Finsterwalder, U.

1981-06-30

59

Electron-beam-activated light-emitting polymer nanofibers.  

PubMed

We demonstrate a simple approach to high-stability light-emitting polymer nanofibers. We show that nonluminescent polyacrylamide (PAM) nanofibers, when being irradiated by electron beams, can be locally activated into light-emitting nanofibers with high resistance to photobleaching, precise emission patterns, spectrally tunable emission, high repeatability, and great mechanical flexibility. Compared to unirradiated nanofibers, the electron-beam-activated PAM nanofibers show an obvious increase in refractive index of about 0.1. Due to its high versatility, the electron-beam-activated nanofiber demonstrated here represents a promising nanometer-scale integratable light source for functional nanophotonic circuits or devices. PMID:23546236

Wang, Pan; Li, Zhiyong; Zhang, Lei; Tong, Limin

2013-04-01

60

bioLights: Light emitting wear for visualizing lower-limb muscle activity  

Microsoft Academic Search

Analysis of muscle activity by electrophysiological techniques is commonly used to analyze biomechanics. Although the simultaneous and intuitive understanding of both muscle activity and body motion is important in various fields, it is difficult to realize. This paper proposes a novel technique for visualizing physiological signals related to muscle activity by means of surface electromyography. We developed a wearable light-emitting

Naoto Igarashi; Kenji Suzuki; Hiroaki Kawamoto; Yoshiyuki Sankai

2010-01-01

61

Advanced Light Source: Activity report 1993  

SciTech Connect

The Advanced Light Source (ALS) produces the world`s brightest light in the ultraviolet and soft x-ray regions of the spectrum. The first low-energy third-generation synchrotron source in the world, the ALS provides unprecedented opportunities for research in science and technology not possible anywhere else. This year marked the beginning of operations and the start of the user research program at the ALS, which has already produced numerous high quality results. A national user facility located at Lawrence Berkeley Laboratory of the University of California, the ALS is available to researchers from academia, industry, and government laboratories. This report contains the following: (1) director`s message; (2) operations overview; (3) user program; (4) users` executive committee; (5) industrial outreach; (6) accelerator operations; (7) beamline control system; (8) insertion devices; (9) experimental systems; (10) beamline engineering; (11) first results from user beamlines; (12) beamlines for 1994--1995; (13) special events; (14) publications; (15) advisory panels; and (16) ALS staff.

Not Available

1994-11-01

62

Light-Activated Pharmaceuticals: Mechanisms and Detection  

PubMed Central

Photodynamic therapy relies on the interaction between light, oxygen and a photosensitizing agent. Its medical significance relates to the ability of certain agents, usually based on porphyrin or phthalocyanine structures, to localize somewhat selectively in neoplastic cells and their vasculature. Subsequent irradiation, preferably at a sufficiently high wavelength to have a significant pathway through tissues, results in a photophysical reaction whereby the excited state of the photosensitizing agent transfers energy to molecular oxygen and results in the formation of reactive oxygen species. Analogous reactive nitrogen species are also formed. These contain both nitrogen and oxygen atoms. The net result is both direct tumor cell death and a shutdown of the tumor vasculature. Other processes may also occur that promote the anti-tumor response but these are outside the scope of this review. PMID:23990688

Kessel, David; Reiners, John

2013-01-01

63

Floating and Falling Flows  

NSDL National Science Digital Library

Students discover fluid dynamics related to buoyancy through experimentation and optional photography. Using one set of fluids, they make light fluids rise through denser fluids. Using another set, they make dense fluids sink through a lighter fluid. In both cases, they see and record beautiful fluid motion. Activities are also suitable as class demonstrations. The natural beauty of fluid flow opens the door to seeing the beauty of physics in general.

Flow Visualization Laboratory, Department of Mechanical Engineering,

64

Strong growth limitation of a floating plant (Lemna gibba) by the submerged macrophyte (Elodea nuttallii) under laboratory conditions  

Microsoft Academic Search

1. The asymmetric competition for light and nutrients between floating and submerged aquatic plants is thought to be key in explaining why dominance by either of these groups can be stable and difficult to change. 2. Although the shading effect of floating plants on submerged plants has been well documented, the impact of submerged plants on floating plants has been

SANDOR SZABO; MARTEN SCHEFFER; RUDI ROIJACKERS; BEATA WALUTO; L. Zambrano; PETER T. NAGY; GABOR BORICS

2010-01-01

65

Light-activated antibacterial surfaces comprise photosensitizers.  

PubMed

Antibacterial surfaces were prepared using a base polyethylene sheet topped with a layer containing a mixed powder of poly (vinylidene fluoride) and photosensitizers (PSs). A crimpled stamp was placed on the mixed powder, and then it was passed through a heating and pressing device. The three chosen PSs were rose bengal, toluidine blue O and methylene blue. Scanning electron microscope analysis showed that the PS surface texture was coarse and highly developed. Measurement of the apparent contact angles of the droplets deposited on the PS surfaces using goniometry showed that all three surfaces were hydrophobic. Photodynamic analysis of the surfaces into which the PSs were incorporated indicated significant reactive oxygen species formation after illumination with light fluency rate of 1.46 mW cm(-2) for 30 min. Photodynamic inactivation assays performed in nutrient broth demonstrated more than 4 log reduction of the attached Escherichia coli after illumination (1.46 mW cm(-2)) for 24 h when the inoculum was 10(3) CFU mL(-1). However, more than 4 log reduction of Staphylococcus aureus occurred even when the cultures were illuminated for only 6 h. Our results provide an inexpensive, simple, state-of-the-art method for preparing antibacterial surfaces that may help prevent infections in hospital surroundings and in some medical devices. PMID:21883241

Cahan, Rivka; Schwartz, Ronen; Langzam, Yakov; Nitzan, Yeshayahu

2011-01-01

66

Serial floating point formatter  

SciTech Connect

A floating point formatter for changing fixed point serial digital data, such as that received by a seismic data acquisition system, is disclosed wherein fixed point serial digital data is received and scaled to remove any bias added by preamplification. The scaled data is shifted a predetermined number of bits and a resulting exponent is calculated. The shifted data signal and corresponding exponent are combined and further scaled to permit stacking the data without exceeding the system capacity.

Peterson, R. D.; Penner, W. A.

1985-11-12

67

DNA endonuclease activities on psoralen plus ultraviolet light treated DNA  

SciTech Connect

Activities of nuclear DNA endonucleases (Endos) from normal human lymphoblastoid cells on DNA treated with the DNA interstrand cross-linking agents 4,5'8-trimethyl psoralen (TMP) or 8-methoxypsoralen (MOP) plus long-wavelength (320-400 nm) ultraviolet light (UVA) were examined. Chromatin-associated DNA Endos were isolated from both cell lines and subjected to isoelectric focusing (IF). Each IF fraction was assayed for DNA Endo activity. Peaks of activity were pooled and assayed for activity on undamaged PM2 bacteriophage DNA and on PM2 DNA that had been treated with 15 ..mu..g/ml TMP or MOP in the dark and then exposed to UVA light. Unbound psoralen was removed by dialysis and a second dose of UVA light was given in order to increase the number of DNA cross-links. Two Endo activities were found which were active on TMP- and MOP-DNA: a major one, pI 4.6, which is also active on intercalated DNA, and a second, lesser one, pI 7.6, which is active on UVC (254 nm) light irradiated DNA. These results indicate that there are two different DNA Endos which act on both TMP- and MOP-treated DNA and that the major activity recognizes the intercalation of, and/or the cross-link produced by interaction of, psoralen with DNA.

Lambert, M.W.; Clark, M.

1986-03-01

68

CASES Online: Lights Out! - A Circuit Activity  

NSDL National Science Digital Library

This item is Problem-Based Learning (PBL) activity for high school physics that asks learners to construct a flashlight using only broken and salvaged parts. In the opening scenario, a group of students are lost in a fully dark cave. One flashlight breaks in a fall and the battery dies in the other. Students have a time limit to figure out how to make the circuit work with only "salvage" items provided for the lesson. SEE RELATED MATERIALS for a link to the student materials that accompany this lesson plan (includes scene script and rubric for problem solving). CASES Online is a growing collection of inquiry-based lessons developed to explore the science behind real-world problems. More than 200 cases are available, covering all strands of the sciences. The cases are grounded in Problem-Based Learning (PBL) and Investigative Case-Based Learning (ICBL) pedagogy.

Toebbe, Jonathan

2010-06-22

69

Advanced light source. Activity report 1995  

SciTech Connect

The ALS Activity Report is designed to share the breadth, variety, and interest of the scientific program and ongoing R&D efforts in a form that is accessible to a broad audience. Recent research results are presented in six sections, each representing an important theme in ALS science. These results are designed to demonstrate the capabilities of the ALS, rather than to give a comprehensive review of 1995 experiments. Although the scientific program and facilities report are separate sections, in practice the achievements and accomplishments of users and ALS staff are interdependent. This user-staff collaboration is essential to help us direct our efforts toward meeting the needs of the user community, and to ensure the continued success of the ALS as a premier facility.

NONE

1996-07-01

70

Light and dark active phosphodiesterase regulation in salamander rods  

Microsoft Academic Search

ABSTRACT We studied the activation of 3',5'-cyclic guanosine monophosphate (cGMP) phosphodiesteras,e (PDE) by using a cell-permeant,enzyme,inhibitor. Rods of Ambystoma tigrinum held,in a suction electrode,were,jumped,into a stream,of 3-isobutyl-l-methylxanthine (IBMX), 0.01-1 mM. Initial transient light-sensitive currents,fit the,notion,that dark,and,light-activated forms,of PDE contributed independently,to metabolic,activity and,were,equivalently,inhibited,by,IBMX (apparent Ki 30 tzm). Inhibition developed within 50 ms, producing a step decrease of enzyme velocity, which could

W. H. Cobbs

1991-01-01

71

Effect of various visible light photoinitiators on the polymerization and color of light-activated resins.  

PubMed

The purpose of this study was to investigate effects of various visible light photoinitiators on the polymerization efficiency and color of the light-activated resins. Four photoinitiators, including camphorquinone, phenylpropanedione, monoacrylphosphine oxide (TPO), and bisacrylphosphine oxide (Ir819), were used. Each photoinitiator was dissolved in a Bis-GMA and TEGDMA monomer mixture. Materials were polymerized using dental quartz-tungsten halogen lamp (QTH), plasma-ark lamp and blue LED light-curing units, and a custom-made violet LED light unit. The degree of monomer conversion and CIE L*a*b* color values of the resins were measured using a FTIR and spectral transmittance meter. The degree of monomer conversions of TPO- and Ir819-containing resins polymerized with the violet-LED unit were higher than camphorquinone-containing resin polymerized with the QTH light-curing unit. The lowest color values were observed for the TPO-containing resin. Our results indicate that the TPO photoinitiator and the violet-LED light unit may provide a useful and improved photopolymerization system for dental light-activated resins. PMID:19721283

Arikawa, Hiroyuki; Takahashi, Hideo; Kanie, Takahito; Ban, Seiji

2009-07-01

72

40 CFR 65.45 - External floating roof converted into an internal floating roof.  

Code of Federal Regulations, 2010 CFR

... 2010-07-01 false External floating roof converted into an internal floating roof. 65.45...Storage Vessels § 65.45 External floating roof converted into...material emissions by using an external floating roof converted...

2010-07-01

73

Analysis of an Anomaly: The Increase in Time Float following Consumption  

PubMed Central

One fundamental axiom for project plan and schedule relates to the notion that time float will be reduced following its consumption. However, an anomalous scenario can emerge in which an activity's time float increases following its consumption. By exploring the associations between time float and paths in activity networks, we (a) reveal the conditions under which the anomaly occurs and (b) summarize laws related to total float. An activity's total float increases in parallel with its duration prolongation within a given boundary but remains constant or decreases in parallel with a prolongation outside the boundary. Furthermore, whereas a prolongation of an activity's duration in excess of classic total float does not delay project completion time, a lag of its start time to a degree slightly greater than the total float does. This analysis reveals different types of total float that correspond to different ways of usage. From this, we offer definitions for translation total float and prolongation total float that deviate from traditional conventions regarding the uniqueness of total float. PMID:25250376

Qi, Jianxun; Su, Zhixiong

2014-01-01

74

Ultraviolet B light stimulates hornet activities - a review  

NASA Astrophysics Data System (ADS)

For more than 30 years now, we have been gathering data on vespan activity in the field and laboratory under the influence of various factors. We found that light is most influential on the behaviour and activities of hornets (Hymenoptera, Vespinae); among various light wavelengths, the greatest influence was ascribed to the ultraviolet bandwidth (UVB). Prominent vespan activities outside their nest included digging, that is, the removal of soil from the nest, and we found this activity to take place at high noon, when the UV radiation, especially the UVB fraction, is maximal. In fact the digging activity of hornets was at times fully coordinated with the solar radiation, especially with the UVB portion of it, so that in daytime hours with diminished UV radiation, as in the morning or the afternoon, this activity and also flights outside the nest were accordingly curtailed, whereas at night there was no vespan flight at all. Under laboratory conditions, we found that hornets subjected to ether anaesthesia awaken faster when exposed to UV light than do control hornets left in the dark. In this connection, the exposure of pieces of hornet cuticle to UV light resulted in enhanced light absorption by the cuticle, but the absorption level reverted to normal after a period of rest in the dark. Tests for cuticular fluorescence after its irradiation with UVB light (290 nm) revealed a dominant emission in both UV and visible light. Furthermore, exposure of the cuticle of either live or dead hornets to light results in a photovoltaic effect which amplifies under UV irradiation. The hornet cuticle appears to behave like a semiconductor with traps and under the influence of light irradiation the electrical conductivity diminishes. The cuticle exposed to UV irradiation undergoes polarization, as do ferroelectric substances after being exposed to an electric field. The present paper summarizes the results of experiments and observations carried out on both live and dead hornets, from all of which emerges the conclusion that UV light is a factor which attracts hornets and influences them, while the hornets, in turn, utilize it for their own purposes. The latter utilization is achieved in cooperation with bacterial symbionts such as Staphylococcus xylosus and S. gallinarum.

Ishay, Jacob S.; Kirshboim, Shira

2000-07-01

75

Floating offshore structure  

SciTech Connect

A floating offshore structure which is moored at a fixed position on the sea by means of mooring hawsers and anchors connected to the ends thereof respectively for conducting a submarine excavating operation from a deck of the structure. The structure includes a moorage hull part provided with a vertical through-hole formed therein for receiving an excavating drill pipe and the mooring hawsers and a movable hull part connected to the moorage hull part so as to be rotatable within a horizontal plane. The movable hull part is constituted as a hull defining the outer wall of the floating offshore structure and connected with the moorage hull part by inserting it into a moorage hull part receiving hole formed at a position closer to the bow thereof. The movable hull part has near its water plane a horizontal section with a substantially oval shape formed by a fore draft part in a substantially circular or polygonal shape, with the moorage hull part receiving hole as a center and an after draft part taperingly projecting aft from the fore draft part.

Oshima, M.; Narita, H.; Tabuchi, H.; Yashima, N.

1985-05-28

76

The effect of light-activation sources on tooth bleaching  

PubMed Central

Vital bleaching is one of the most requested cosmetic dental procedures asked by patients who seek a more pleasing smile. This procedure consists of carbamide or hydrogen peroxide gel applications that can be applied in-office or by the patient (at-home/overnight bleaching system). Some in-office treatments utilise whitening light with the objective of speeding up the whitening process. The objective of this article is to review and summarise the current literature with regard to the effect of light-activation sources on in-office tooth bleaching. A literature search was conducted using Medline, accessed via the National Library of Medicine Pub Med from 2003 to 2013 searching for articles relating to effectiveness of light activation sources on in-office tooth bleaching. This study found conflicting evidence on whether light truly improve tooth whitening. Other factors such as, type of stain, initial tooth colour and subject age which can influence tooth bleaching outcome were discussed. Conclusions: The use of light activator sources with in-office bleaching treatment of vital teeth did not increase the efficacy of bleaching or accelerate the bleaching.

Baroudi, Kusai; Hassan, Nadia Aly

2014-01-01

77

Global Positioning System Synchronized Active Light Autonomous Docking System  

NASA Technical Reports Server (NTRS)

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprises at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Howard, Richard (inventor)

1994-01-01

78

Global Positioning System Synchronized Active Light Autonomous Docking System  

NASA Technical Reports Server (NTRS)

A Global Positioning System Synchronized Active Light Autonomous Docking System (GPSSALADS) for automatically docking a chase vehicle with a target vehicle comprising at least one active light emitting target which is operatively attached to the target vehicle. The target includes a three-dimensional array of concomitantly flashing lights which flash at a controlled common frequency. The GPSSALADS further comprises a visual tracking sensor operatively attached to the chase vehicle for detecting and tracking the target vehicle. Its performance is synchronized with the flash frequency of the lights by a synchronization means which is comprised of first and second internal clocks operatively connected to the active light target and visual tracking sensor, respectively, for providing timing control signals thereto, respectively. The synchronization means further includes first and second Global Positioning System receivers operatively connected to the first and second internal clocks, respectively, for repeatedly providing simultaneous synchronization pulses to the internal clocks, respectively. In addition, the GPSSALADS includes a docking process controller means which is operatively attached to the chase vehicle and is responsive to the visual tracking sensor for producing commands for the guidance and propulsion system of the chase vehicle.

Howard, Richard T. (Inventor); Book, Michael L. (Inventor); Bryan, Thomas C. (Inventor); Bell, Joseph L. (Inventor)

1996-01-01

79

Float level switch for a nuclear power plant containment vessel  

DOEpatents

This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel. 1 figures.

Powell, J.G.

1993-11-16

80

Float level switch for a nuclear power plant containment vessel  

DOEpatents

This invention is a float level switch used to sense rise or drop in water level in a containment vessel of a nuclear power plant during a loss of coolant accident. The essential components of the device are a guide tube, a reed switch inside the guide tube, a float containing a magnetic portion that activates a reed switch, and metal-sheathed, ceramic-insulated conductors connecting the reed switch to a monitoring system outside the containment vessel. Special materials and special sealing techniques prevent failure of components and allow the float level switch to be connected to a monitoring system outside the containment vessel.

Powell, James G. (Clifton Park, NY)

1993-01-01

81

Obesity = physical activity + dietary intake + sleep stages + light exposure.  

PubMed

Daily levels of physical activity and calories from dietary intake have been the focus of obesity prevention measures. Recent findings have made a twist in the line of thinking. The timing of physical exercise and that of dietary intake are also important to obesity prevention. Night-time sleep and exposure to light are therefore important targets of intervention. PMID:25088724

Partonen, Timo

2014-08-01

82

Advanced Light Source Activity Report 1997/1998  

SciTech Connect

This Lawrence Berkeley National Laboratory, Advanced Light Source (ALS) activity report for 1997/98 discusses the following topics: Introduction and Overview; Science Highlights; Facility Report; Special Events; ALS Advisory Panels 1997/98; ALS Staff 1997/98 and Facts and Figures for the year.

Greiner, Annette (ed.)

1999-03-01

83

Selenium bond decreases ON resistance of light-activated switch  

NASA Technical Reports Server (NTRS)

Vitrified amorphous selenium bond decreases the ON resistance of a gallium arsenide-silicon light-activated, low-level switch. The switch is used under a pulse condition to prolong switch life and minimize errors due to heating, devitrification, and overdrawing.

1965-01-01

84

Azobenzene-based chloride transporters with light-controllable activities.  

PubMed

Synthetic chloride transporters containing two urea groups linked through a diazobenzene spacer have been prepared and the trans-to-cis isomerization by light stimulation results in dramatic changes in the chloride transport activities across lipid and cell membranes. PMID:25350406

Choi, Ye Rin; Kim, Gyu Chan; Jeon, Hae-Geun; Park, Jinhong; Namkung, Wan; Jeong, Kyu-Sung

2014-12-18

85

75 FR 80471 - Takes of Marine Mammals Incidental to Specified Activities; St. George Reef Light Station...  

Federal Register 2010, 2011, 2012, 2013

...to Specified Activities; St. George Reef Light Station Restoration and Maintenance at Northwest...operations, and lighthouse renovation and light maintenance activities on the St. George Reef Light Station on Northwest Seal Rock (NWSR)...

2010-12-22

86

76 FR 79157 - Takes of Marine Mammals Incidental to Specified Activities; St. George Reef Light Station...  

Federal Register 2010, 2011, 2012, 2013

...to Specified Activities; St. George Reef Light Station Restoration and Maintenance at Northwest...aircraft operations, lighthouse renovation, and light maintenance activities on the St. George Reef Light Station on Northwest Seal Rock (NWSR)...

2011-12-21

87

77 FR 8811 - Takes of Marine Mammals Incidental to Specified Activities; St. George Reef Light Station...  

Federal Register 2010, 2011, 2012, 2013

...to Specified Activities; St. George Reef Light Station Restoration and Maintenance at Northwest...operations, and lighthouse renovation and light maintenance activities on the St. George Reef Light Station on Northwest Seal Rock (NWSR)...

2012-02-15

88

78 FR 1838 - Takes of Marine Mammals Incidental to Specified Activities; St. George Reef Light Station...  

Federal Register 2010, 2011, 2012, 2013

...to Specified Activities; St. George Reef Light Station Restoration and Maintenance at Northwest...aircraft operations, lighthouse renovation, and light maintenance activities on the St. George Reef Light Station on Northwest Seal Rock (NWSR)...

2013-01-09

89

76 FR 10564 - Takes of Marine Mammals Incidental to Specified Activities; St. George Reef Light Station...  

Federal Register 2010, 2011, 2012, 2013

...to Specified Activities; St. George Reef Light Station Restoration and Maintenance at Northwest...operations, and lighthouse renovation and light maintenance activities on the St. George Reef Light Station on Northwest Seal Rock (NWSR)...

2011-02-25

90

78 FR 71576 - Takes of Marine Mammals Incidental to Specified Activities; St. George Reef Light Station...  

Federal Register 2010, 2011, 2012, 2013

...to Specified Activities; St. George Reef Light Station Restoration and Maintenance at Northwest...operations, and lighthouse renovation and light maintenance activities on the St. George Reef Light Station on Northwest Seal Rock (NWSR)...

2013-11-29

91

Effect of temperature and nutrients on the competition between free-floating Salvinia natans and submerged Elodea nuttallii in mesocosms  

Microsoft Academic Search

In many aquatic ecosystems, free-floating plants compete with submerged plants for nutrients and light. Being on top of the water surface free-floating plants are superior competitors for light. Submerged plants can take up nutrients from the sediment and the water column, hereby reducing these levels for free-floating plants. Global warming may change chances of successful species invasion and can alter

J. J. C. Netten; G. H. P. Arts; R. Gylstra; Nes van E. H; M. Scheffer; R. M. M. Roijackers

2010-01-01

92

Floating Cities, Islands and States  

E-print Network

Many small countries are in need of additional territory. They build landfills and expensive artificial islands. The ocean covers 71 per cent of the Earth surface. Those countries (or persons of wealth) starting the early colonization of the ocean may obtain advantages through additional territory or creating their own independent state. An old idea is building a big ship. The best solution to this problem, however, is the provision of floating cities, islands, and states. The author idea is to use for floating cities, islands, and states a cheap floating platform created from a natural ice field taken from the Arctic or Antarctic oceans. These cheap platforms protected by air-film (bottom and sides) and a conventional insulating cover (top) and having a cooling system can exist for an unlimited time. They can be increased in number or size at any time, float in warm oceans, travel to different continents and countries, serve as artificial airports, harbors and other marine improvements, as well as floating cities and industrial bases for virtually any use. Author researches and computes parameters of these ice floating platforms, other methods of building such floating territory, compares them and shows that the offered method is the most cheap and efficient means of ocean colonization.

Alexander Bolonkin

2008-04-04

93

Channelrhodopsins: visual regeneration and neural activation by a light switch  

PubMed Central

The advent of optogenetics provides a new direction for the field of neuroscience and biotechnology, serving both as a refined investigative tool and as potential cure for many medical conditions via genetic manipulation. Although still in its infancy, recent advances in optogenetics has made it possible to remotely manipulate in vivo cellular functions using light. Coined Nature Methods’ ‘Method of the Year’ in 2010, the optogenetic toolbox has the potential to control cell, tissue and even animal behaviour. This optogenetic toolbox consists of light-sensitive proteins that are able to modulate membrane potential in response to light. Channelrhodopsins (ChR) are light-gated microbial ion channels, which were first described in green algae. ChR2 (a subset of ChR) is a seven transmembrane a helix protein, which evokes membrane depolarization and mediates an action potential upon photostimulation with blue (470 nm) light. By contrast to other seven-transmembrane proteins that require second messengers to open ion channels, ChR2 form ion channels themselves, allowing ultrafast depolarization (within 50 milliseconds of illumination). It has been shown that integration of ChR2 into various tissues of mice can activate neural circuits, control heart muscle contractions, and even restore breathing after spinal cord injury. More compellingly, a plethora of evidence has indicated that artificial expression of ChR2 in retinal ganglion cells can reinstate visual perception in mice with retinal degeneration. PMID:23664865

Natasha, G; Tan, Aaron; Farhatnia, Yasmin; Rajadas, Jayakumar; Hamblin, Michael R.; Khaw, Peng T.; Seifalian, Alexander M.

2013-01-01

94

Channelrhodopsins: visual regeneration and neural activation by a light switch.  

PubMed

The advent of optogenetics provides a new direction for the field of neuroscience and biotechnology, serving both as a refined investigative tool and as potential cure for many medical conditions via genetic manipulation. Although still in its infancy, recent advances in optogenetics has made it possible to remotely manipulate in vivo cellular functions using light. Coined Nature Methods' 'Method of the Year' in 2010, the optogenetic toolbox has the potential to control cell, tissue and even animal behaviour. This optogenetic toolbox consists of light-sensitive proteins that are able to modulate membrane potential in response to light. Channelrhodopsins (ChR) are light-gated microbial ion channels, which were first described in green algae. ChR2 (a subset of ChR) is a seven transmembrane ? helix protein, which evokes membrane depolarization and mediates an action potential upon photostimulation with blue (470 nm) light. By contrast to other seven-transmembrane proteins that require second messengers to open ion channels, ChR2 form ion channels themselves, allowing ultrafast depolarization (within 50 milliseconds of illumination). It has been shown that integration of ChR2 into various tissues of mice can activate neural circuits, control heart muscle contractions, and even restore breathing after spinal cord injury. More compellingly, a plethora of evidence has indicated that artificial expression of ChR2 in retinal ganglion cells can reinstate visual perception in mice with retinal degeneration. PMID:23664865

G, Natasha; Tan, Aaron; Farhatnia, Yasmin; Rajadas, Jayakumar; Hamblin, Michael R; Khaw, Peng T; Seifalian, Alexander M

2013-06-25

95

An active lighting module with natural light guiding system and solid state source for indoor illumination  

Microsoft Academic Search

Recently, many researches focus on healthy lighting with sunlight. A Natural Light Guiding System includes collecting, transmitting, and lighting parts. In general, the lighting module of the Natural Light Guiding System only uses scattering element, such as diffuser, to achieve uniform illumination. With the passive lighting module, the application of the Natural Light Guiding System is limited because sunlight is

Chi-An Chen; Yi-Yung Chen; Allen Jong-Woei Whang

2009-01-01

96

Organic molecular floating gate memories  

E-print Network

Flash memory devices dominate the non-volatile memory market, with device structures that utilize charge storage in polysilicon floating gates imbedded in insulating silicon oxide films'. As demands for high storage density, ...

Paydavosi, Sarah

2011-01-01

97

Control development for floating wind  

NASA Astrophysics Data System (ADS)

Control of a floating wind turbine has proven to be challenging, but essential for lowering the cost of floating wind energy. Topic of a recent joint R&D project by GustoMSC, MARIN and ECN, is the concept design and verification with coupled simulations and model tests of the GustoMSC Tri-Floater. Only using an integral design approach, including mooring and control design, a cost effective system can be obtained. In this project, ECN developed a general floating wind turbine control strategy and applied this in a case study to the GustoMSC Tri-Floater and the OC3Hywind spar, both equipped with the NREL 5MW RWT. The designed controller ensures stable operation, while maintaining proper speed and power regulation. The motions of the floating support are reduced and substantial load reduction has been achieved.

Savenije, Feike; Peeringa, Johan

2014-06-01

98

Floating into Thin Air  

SciTech Connect

On May 18, 2005, a giant helium balloon carrying the High Energy Focusing Telescope (HEFT) sailed into the spring sky over the deserts of New Mexico. The spindly steel and aluminum gondola that houses the optics, detectors, and other components of the telescope floated for 25 hours after its launch from Fort Sumner, New Mexico. For 21 of those hours, the balloon was nearly 40 kilometers above Earth's surface--almost four times higher than the altitude routinely flown by commercial jet aircraft. In the upper reaches of Earth's atmosphere, HEFT searched the universe for x-ray sources from highly energetic objects such as binary stars, galaxy clusters, and supermassive black holes. Before landing in Arizona, the telescope observed and imaged a dozen scientific targets by capturing photons emitted from these objects in the high-energy (hard) x-ray range (above 10 kiloelectronvolts). Among these targets were the Crab synchrotron nebula, the black hole Cygnus X-1 (one of the brightest x-ray sources in the sky), and the blazar 3C454.3. The scientific data gathered from these targets are among the first focused hard x-ray images returned from high altitudes.

Hazi, A U

2007-02-06

99

Tests find hammering, fluid cutting, erosion cause float shoe failures  

Microsoft Academic Search

The results of a systematic test program to evaluate float equipment performance are presented. The testing has destroyed, over an eightmonth period, 160 float valves, float shoes and float collars. A new float valve design with greater resistance to failure has been developed as a result of the testing. New float collars and float shoes are expected to provide the

Stringfellow

1985-01-01

100

46 CFR 117.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2013 CFR

...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2013-10-01

101

46 CFR 117.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2012 CFR

...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2012-10-01

102

46 CFR 117.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2011 CFR

...of a dark color or of a type certified to be resistant to deterioration from ultraviolent light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2011-10-01

103

Photocatalytic activities of various pentavalent bismuthates under visible light irradiation  

SciTech Connect

LiBiO{sub 3}, NaBiO{sub 3}, MgBi{sub 2}O{sub 6}, KBiO{sub 3}, ZnBi{sub 2}O{sub 6}, SrBi{sub 2}O{sub 6}, AgBiO{sub 3}, BaBi{sub 2}O{sub 6} and PbBi{sub 2}O{sub 6} were synthesized by various processes such as hydrothermal treatment, heating and so on. These materials were examined for their photocatalytic activities in the decolorization of methylene blue and decomposition of phenol under visible light irradiation. For methylene blue decolorization, the presence of KBiO{sub 3} resulted in complete decoloration within 5 min. For phenol decomposition, NaBiO{sub 3} showed the highest activity, while LiBiO{sub 3}, SrBi{sub 2}O{sub 6} and BaBi{sub 2}O{sub 6} possessed almost comparable decomposition rates. Their decomposition rates were apparently higher than that by anatase (P25) under UV irradiation. - Graphical abstract: Nine pentavalent bismuthates were synthesized and were examined for their photocatalytic activities by decomposition of phenol under visible light irradiation. NaBiO{sub 3}, LiBiO{sub 3}, SrBi{sub 2}O{sub 6} and BaBi{sub 2}O{sub 6} indicated faster decomposition rate than that of anatase (P25) under UV-vis light irradiation. Highlights: > KBiO{sub 3} decolorize methylene blue aqueous solution immediately within 5 min. > NaBiO{sub 3}, LiBiO{sub 3}, SrBi{sub 2}O{sub 6} and BaBi{sub 2}O{sub 6} indicated high decomposition rate of phenol. > The d electron of Zn, Ag and Pb form broad conduction band. > The broad conduction band poses to diminish photocatalytic activity.

Takei, Takahiro, E-mail: takei@yamanashi.ac.jp [Center for Crystal Science and Technology, University of Yamanashi, 7-32, Miyamae, Kofu, Yamanashi 400-8511 (Japan); Haramoto, Rie; Dong, Qiang; Kumada, Nobuhiro; Yonesaki, Yoshinori; Kinomura, Nobukazu [Center for Crystal Science and Technology, University of Yamanashi, 7-32, Miyamae, Kofu, Yamanashi 400-8511 (Japan); Mano, Takayuki; Nishimoto, Shunsuke; Kameshima, Yoshikazu; Miyake, Michihiro [Department of Environmental Chemistry and Materials, Okayama University, 3-1-1, Tsushimanaka, Okayama 700-8530 (Japan)

2011-08-15

104

Slow-light-enhanced gain in active photonic crystal waveguides  

NASA Astrophysics Data System (ADS)

Passive photonic crystals have been shown to exhibit a multitude of interesting phenomena, including slow-light propagation in line-defect waveguides. It was suggested that by incorporating an active material in the waveguide, slow light could be used to enhance the effective gain of the material, which would have interesting application prospects, for example enabling ultra-compact optical amplifiers for integration in photonic chips. Here we experimentally investigate the gain of a photonic crystal membrane structure with embedded quantum wells. We find that by solely changing the photonic crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar to those realized in state-of-the-art semiconductor optical amplifiers should be attainable in compact photonic integrated amplifiers.

Ek, Sara; Lunnemann, Per; Chen, Yaohui; Semenova, Elizaveta; Yvind, Kresten; Mork, Jesper

2014-09-01

105

Active dielectric antenna on chip for spatial light modulation  

PubMed Central

Integrated photonic resonators are widely used to manipulate light propagation in an evanescently-coupled waveguide. While the evanescent coupling scheme works well for planar optical systems that are naturally waveguide based, many optical applications are free-space based, such as imaging, display, holographics, metrology and remote sensing. Here we demonstrate an active dielectric antenna as the interface device that allows the large-scale integration capability of silicon photonics to serve the free-space applications. We show a novel perturbation-base diffractive coupling scheme that allows a high-Q planer resonator to directly interact with and manipulate free-space waves. Using a silicon-based photonic crystal cavity whose resonance can be rapidly tuned with a p-i-n junction, a compact spatial light modulator with an extinction ratio of 9.5?dB and a modulation speed of 150?MHz is demonstrated. Method to improve the modulation speed is discussed. PMID:23152946

Qiu, Ciyuan; Chen, Jianbo; Xia, Yang; Xu, Qianfan

2012-01-01

106

Parade Float Construction 101  

E-print Network

to locate a variety of tools. Here are a few you might want to plan for: a table saw or circular saw, saber. This superstructure will generally be used to #12;support chicken wire, cardboard or other light decorating items

Moore, Paul A.

107

Asymmetric photoredox transition-metal catalysis activated by visible light.  

PubMed

Asymmetric catalysis is seen as one of the most economical strategies to satisfy the growing demand for enantiomerically pure small molecules in the fine chemical and pharmaceutical industries. And visible light has been recognized as an environmentally friendly and sustainable form of energy for triggering chemical transformations and catalytic chemical processes. For these reasons, visible-light-driven catalytic asymmetric chemistry is a subject of enormous current interest. Photoredox catalysis provides the opportunity to generate highly reactive radical ion intermediates with often unusual or unconventional reactivities under surprisingly mild reaction conditions. In such systems, photoactivated sensitizers initiate a single electron transfer from (or to) a closed-shell organic molecule to produce radical cations or radical anions whose reactivities are then exploited for interesting or unusual chemical transformations. However, the high reactivity of photoexcited substrates, intermediate radical ions or radicals, and the low activation barriers for follow-up reactions provide significant hurdles for the development of efficient catalytic photochemical processes that work under stereochemical control and provide chiral molecules in an asymmetric fashion. Here we report a highly efficient asymmetric catalyst that uses visible light for the necessary molecular activation, thereby combining asymmetric catalysis and photocatalysis. We show that a chiral iridium complex can serve as a sensitizer for photoredox catalysis and at the same time provide very effective asymmetric induction for the enantioselective alkylation of 2-acyl imidazoles. This new asymmetric photoredox catalyst, in which the metal centre simultaneously serves as the exclusive source of chirality, the catalytically active Lewis acid centre, and the photoredox centre, offers new opportunities for the 'green' synthesis of non-racemic chiral molecules. PMID:25373679

Huo, Haohua; Shen, Xiaodong; Wang, Chuanyong; Zhang, Lilu; Röse, Philipp; Chen, Liang-An; Harms, Klaus; Marsch, Michael; Hilt, Gerhard; Meggers, Eric

2014-11-01

108

Effects of size and light on respiration and activity of walleye pollock ( Theragra chalcogramma) larvae  

Microsoft Academic Search

The respiration rate and swimming activity of walleye pollock (Theragra chalcogramma) larvae were measured in the laboratory to determine how these were affected by body size (measured as dry weight), and amount of light. Size influenced respiration rates, but not activity. Activity increased with increased light, and as walleye pollock larvae developed, light had an increasingly important effect on respiration

Steven M. Porter

2001-01-01

109

Light-mediated antibacterial activity of Lippia origanoides H.B.K. in vitro.  

PubMed

An ethanol extract and different partition fractions obtained from Lippia origanoides H.B.K. were assayed for light-mediated activity against strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Identical assays were conducted with and without exposure to UV-A (400-315 nm) light to test for light enhanced activity. The ethanol extract and dichloromethane fraction showed light-mediated activity against the S. aureus strain, but not against the E. coli strain. The dichloromethane fraction was more active than the ethanol extract. Naringenin did not display light-mediated activity against the tested bacteria, indicating that the light-mediated antimicrobial activity of the dichloromethane fraction is not due to its major component. The results represent the first report of light-mediated antimicrobial activity of Lippia origanoides and show that its phytochemicals could be used as light-mediated antimicrobial agents. PMID:25360993

Barreto, Humberto M; Coelho, Bruno R C; Menezes-Silva, Suellen M P; Siqueira-Júnior, José P; Coutinho, Henrique D M; Lemos, Izabel Cristina S; Sousa, Taciana O; Silva, Romézio A C; Medeiros, Maria das Graças F; Citó, Antonia M G L; Lopes, José A D

2014-12-12

110

14 CFR 27.753 - Main float design.  

...2014-01-01 false Main float design. 27.753 Section 27...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats....

2014-01-01

111

14 CFR 27.753 - Main float design.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Main float design. 27.753 Section 27...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats....

2012-01-01

112

14 CFR 29.753 - Main float design.  

...2014-01-01 false Main float design. 29.753 Section 29...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats....

2014-01-01

113

14 CFR 27.753 - Main float design.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Main float design. 27.753 Section 27...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats....

2011-01-01

114

14 CFR 25.753 - Main float design.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Main float design. 25.753 Section 25...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design. Each main float must...

2011-01-01

115

14 CFR 25.753 - Main float design.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Main float design. 25.753 Section 25...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design. Each main float must...

2010-01-01

116

14 CFR 27.753 - Main float design.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Main float design. 27.753 Section 27...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats....

2010-01-01

117

14 CFR 25.753 - Main float design.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Main float design. 25.753 Section 25...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design. Each main float must...

2013-01-01

118

14 CFR 25.753 - Main float design.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Main float design. 25.753 Section 25...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design. Each main float must...

2012-01-01

119

14 CFR 25.753 - Main float design.  

...2014-01-01 false Main float design. 25.753 Section 25...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction Floats and Hulls § 25.753 Main float design. Each main float must...

2014-01-01

120

14 CFR 29.753 - Main float design.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Main float design. 29.753 Section 29...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats....

2010-01-01

121

14 CFR 29.753 - Main float design.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Main float design. 29.753 Section 29...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats....

2013-01-01

122

14 CFR 27.753 - Main float design.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Main float design. 27.753 Section 27...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 27.753 Main float design. (a) Bag floats....

2013-01-01

123

14 CFR 29.753 - Main float design.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Main float design. 29.753 Section 29...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats....

2012-01-01

124

14 CFR 29.753 - Main float design.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Main float design. 29.753 Section 29...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction Floats and Hulls § 29.753 Main float design. (a) Bag floats....

2011-01-01

125

Tried and True: Whatever floats your boat  

NSDL National Science Digital Library

Ever since Archimedes ran down the streets of ancient Greece shouting, "Eureka!," scientists have understood that a submerged body displaces a volume of water equalto its own volume. Scientists also came to realize that if a body weighed less than the water it displaced, the body would float. Although this knowledge has been aroundfor nearly 2,500 years, many students still have difficulty explaining how a vessel made of a heavier-than-water material, such as steel, remains afloat. The following triedand true activity provides students with a hands-on experience that explains the principle of buoyancy.

Mcbride, Susan L.

2003-03-01

126

Illinois PER Interactive Examples: Floating Cylinders  

NSDL National Science Digital Library

This is an interactive homework problem for introductory physics students relating to fluids and buoyant force. It involves two differently shaped cylinders with the same mass density floating in a container of non-moving water. The student must determine the ratio of the height of Cylinder #2 above the water to the height of Cylinder #1 above the water. A user-activated "help" sequence is provided for each step of the problem-solving, from conceptual analysis through quantitative calculation. To promote critical thinking, immediate feedback is received for both correct and incorrect responses. This item is part of a larger collection of interactive homework problems for introductory physics.

Gladding, Gary

2008-09-10

127

Flexible dynamics of floating wind turbines  

E-print Network

This work presents Tower Flex, a structural dynamics model for a coupled analysis of offshore floating wind turbines consisting of a tower, a floating platform and a mooring system. In this multi-body, linear frequency-domain ...

Luypaert, Thomas (Thomas J.)

2012-01-01

128

32 CFR 935.165 - Floating objects.  

...INSULAR REGULATIONS WAKE ISLAND CODE Public Safety § 935.165 Floating objects. No person may anchor, moor, or beach any boat, barge, or other floating object on Wake Island in any location or manner other than as prescribed by the...

2014-07-01

129

Light  

NSDL National Science Digital Library

Have you ever wondered how light works? Today, you will be light detectives investigating how light works! Follow the links below to help your investigation! As you are reading about light, write down any words that you do not know. Use the dictionary link to find definitions. Write down their definitions as you find them. First, you will need to know some Light Basics Find out more about light with Light Fun Facts Want to know how glasses help people see? Go to Light and Lenses Look up any unknown words atWebster s Word Central ...

Massey, Miss

2009-03-15

130

Have Floating Rates Been a Success?  

ERIC Educational Resources Information Center

Floating exchange rates have not lived up to all expectations, but neither have they performed as badly as some critics have suggested. Examined are the impact of floating rates on balance of payments adjustment, domestic economic policy, and inflation and the claim that floating rates have displayed excessive fluctuations. (Author/RM)

Higham, David

1983-01-01

131

Dragging a floating horizontal cylinder  

Microsoft Academic Search

A cylinder immersed in a fluid stream experiences a drag, and it is well known that the drag coefficient is a function of the Reynolds number only. Here we study the force exerted on a long horizontal cylinder that is dragged perpendicular to its axis while floating on an air-water interface with a high Reynolds number. In addition to the

Duck-Gyu Lee; Ho-Young Kim

2010-01-01

132

Light-activated heterotrophic growth of the cyanobacterium Synechocystis sp. strain PCC 6803: a blue-light-requiring process.  

PubMed Central

A glucose-tolerant strain of Synechocystis sp. strain 6803 will not grow on glucose under complete darkness unless given a daily pulse of white light, typically 5 min of 40 mumol m-2 s-1 (light-pulsed conditions). The light pulse is insufficient for photoautotrophy, as glucose is required and growth yield is dependent on glucose concentration. Growth rate is independent of fluence, but growth yield is dependent on fluence, saturating at 40 to 75 mumol m-2 s-1. A Synechocystis strain 6803 psbA mutant strain grows under light-pulsed conditions at rates similar to those for the glucose-tolerant strain, indicating that photosystem II is not required for growth. The relative spectral sensitivity of the growth of light-pulsed cultures (growth only in blue light, 400 to 500 nm, maximum at 450 nm) precludes energetic contribution from cyclic electron transport around photosystem I. Pulses of long-wavelength light (i.e., 550 and 650 nm) did not support the growth of Synechocystis strain 6803 and, when supplied before or after a blue-light pulse, did not inhibit blue-light-stimulated growth of Synechocystis strain 6803. We conclude that the required blue-light pulse does not support growth via photosynthetic electron transport but appears instead to function as an environmental signal regulating heterotrophic metabolism, cell division, or other photomorphogenic processes. We have termed the growth of Synechocystis strain 6803 pulsed with light and kept otherwise in complete darkness light-activated heterotrophic growth. This observation of a blue-light requirement for the growth of Synechocystis strain 6803 represents a novel blue light effect on the growth of a cyanobacterium. PMID:1902208

Anderson, S L; McIntosh, L

1991-01-01

133

The coolest 'stars' are free-floating planets  

E-print Network

We show that the coolest known object that is probably formed in a star-like mode is a free-floating planet. We discovered recently that the free-floating planetary mass object OTS,44 (M9.5, ~12 Jupiter masses, age ~2 Myr) has significant accretion and a substantial disk. This demonstrates that the processes that characterize the canonical star-like mode of formation apply to isolated objects down to a few Jupiter masses. We detected in VLT/SINFONI spectra that OTS44 has strong, broad, and variable Paschen beta emission. This is the first evidence for active accretion of a free-floating planet. The object allows us to study accretion and disk physics at the extreme and can be seen as free-floating analog of accreting planets that orbit stars. Our analysis of OTS44 shows that the mass-accretion rate decreases continuously from stars of several solar masses down to free-floating planets. We determined, furthermore, the disk mass (10 Earth masses) and further disk properties of OTS44 through modeling its SED inc...

Joergens, V; Liu, Y; Bayo, A; Wolf, S

2014-01-01

134

A "Floating" Nature Center.  

ERIC Educational Resources Information Center

Presents an overview of the educational programs, concerts, and other activities which take place aboard the 76-foot sloop "Clearwater" in a privately-funded effort to bring New York's Hudson River closer to the people. (WB)

Nolan, Karen

1980-01-01

135

MS Musgrave tethered to starboard sill longeron floats outside PLB  

NASA Technical Reports Server (NTRS)

Extravehicular mobility unit (EMU) suited Mission Specialist (MS) Musgrave, designated EV1, using waist and wrist tethers attached to starboard sill longeron, floats outside payload bay (PLB) and is silhouetted against Earth's surface during extravehicular activity (EVA). MS Peterson, also participating in the EVA, exposed this frame with a 35mm camera while other crewmembers remained in the cabin.

1983-01-01

136

NF-B Activation in Light-Induced Retinal Degeneration in a Mouse Model  

Microsoft Academic Search

PURPOSE. To investigate the modulation of nuclear factor (NF)-B in light-induced photoreceptor degeneration in a mouse model. METHODS. Mice were exposed to intense green light. Light- induced activation of NF-B and its nuclear localization were studied by immunohistochemistry. The NF-B DNA- binding activity in the retinas after exposure to light was measured by electrophoretic mobility shift assay (EMSA). Nuclear transacti-

Tinghuai Wu; Yueguo Chen; Samuel K. S. Chiang; Mark O. M. Tso

2002-01-01

137

Lighting  

NSDL National Science Digital Library

Lighting is one of the key elements used in cinematography. This unit will demonstrate the basic concepts and theory behind lighting which you will use in your future video projects. State Standard 3 - The student will be able to understand and demonstrate lighting systems and how they are used. Objective - At the conclusion of this unit you be able to demonstrate a three-point lighting setup. You will also be able to define each of the following terms and ...

Scholer, Mr.

2009-09-21

138

Advanced Light Source activity report 1996/97  

SciTech Connect

Ten years ago, the Advanced Light Source (ALS) existed as a set of drawings, calculations, and ideas. Four years ago, it stored an electron beam for the first time. Today, the ALS has moved from those ideas and beginnings to a robust, third-generation synchrotron user facility, with eighteen beam lines in use, many more in planning or construction phases, and hundreds of users from around the world. Progress from concepts to realities is continuous as the scientific program, already strong in many diverse areas, moves in new directions to meet the needs of researchers into the next century. ALS staff members who develop and maintain the infrastructure for this research are similarly unwilling to rest on their laurels. As a result, the quality of the photon beams the authors deliver, as well as the support they provide to users, continues to improve. The ALS Activity Report is designed to share the results of these efforts in an accessible form for a broad audience. The Scientific Program section, while not comprehensive, shares the breadth, variety, and interest of recent research at the ALS. (The Compendium of User Abstracts and Technical Reports provides a more comprehensive and more technical view.) The Facility Report highlights progress in operations, ongoing accelerator research and development, and beamline instrumentation efforts. Although these Activity Report sections are separate, in practice the achievements of staff and users at the ALS are inseparable. User-staff collaboration is essential as they strive to meet the needs of the user community and to continue the ALS's success as a premier research facility.

NONE

1997-09-01

139

Dragging a floating horizontal cylinder  

NASA Astrophysics Data System (ADS)

A cylinder immersed in a fluid stream experiences a drag, and it is well known that the drag coefficient is a function of the Reynolds number only. Here we study the force exerted on a long horizontal cylinder that is dragged perpendicular to its axis while floating on an air-water interface with a high Reynolds number. In addition to the flow-induced drag, the floating body is subjected to capillary forces along the contact line where the three phases of liquid/solid/gas meet. We first theoretically predict the meniscus profile around the horizontally moving cylinder assuming the potential flow, and show that the profile is in good agreement with that obtained experimentally. Then we compare our theoretical predictions and experimental measurement results for the drag coefficient of a floating horizontal cylinder that is given by a function of the Weber number and the Bond number. This study can help us to understand the horizontal motion of partially submerged objects at air-liquid interface, such as semi-aquatic insects and marine plants.

Lee, Duck-Gyu; Kim, Ho-Young

2010-11-01

140

NSLS 2007 Activity Report (National Synchrotron Light Source Activity Report 2007)  

Microsoft Academic Search

The National Synchrotron Light Source is one of the world's most productive and cost-effective user facilities. With 2,219 individual users, about 100 more than last year, and a record-high 985 publications, 2007 was no exception. In addition to producing an impressive array of science highlights, which are included in this Activity Report, many NSLS users were honored this year for

L. Miller; K. Nasta

2008-01-01

141

Exogenous control of diel locomotor activity in the whitefish Coregonus clupeaformis: effects of light and temperature  

Microsoft Academic Search

Data on factors determining activity cycles of nearctic fishes are scarce overall, and nonexistent for Coregoniae (family Salmonidae), a group with closely related and somewhat better known palaearctic species. We studied effects of photoperiodicity, light intensity and temperature on diel locomotor activity of lake whitefish Coregonus clupeaformis (Mitchill). Under LD 12:12, a day-active pattern was evident. Under continuous light (LL)

E. Scherer; S. E. Harrison

1988-01-01

142

The role of plasma membrane redox activity in light effects in plants  

Microsoft Academic Search

Stimulations by light of electron transport at the plasma membrane make it possible that redox activity is involved in light-induced signal transduction chains. This is especially true in cases where component(s) of the chain are also located at the plasma membrane. Photosynthetic reactions stimulate transplasma membrane redox activity of mesophyll cells. Activity is measured as a reduction of the nonpermeating

Bernard Rubinstein; Arthur I. Stern

1991-01-01

143

Active Matrix Organic Light Emitting Diode (AMOLED) Environmental Test Report  

NASA Technical Reports Server (NTRS)

This report focuses on the limited environmental testing of the AMOLED display performed as an engineering evaluation by The NASA Johnson Space Center (JSC)-specifically. EMI. Thermal Vac, and radiation tests. The AMOLED display is an active-matrix Organic Light Emitting Diode (OLED) technology. The testing provided an initial understanding of the technology and its suitability for space applications. Relative to light emitting diode (LED) displays or liquid crystal displays (LCDs), AMOLED displays provide a superior viewing experience even though they are much lighter and smaller, produce higher contrast ratio and richer colors, and require less power to operate than LCDs. However, AMOLED technology has not been demonstrated in a space environment. Therefore, some risks with the technology must be addressed before they can be seriously considered for human spaceflight. The environmental tests provided preliminary performance data on the ability of the display technology to handle some of the simulated induced space/spacecraft environments that an AMOLED display will see during a spacecraft certification test program. This engineering evaluation is part of a Space Act Agreement (SM) between The NASA/JSC and Honeywell International (HI) as a collaborative effort to evaluate the potential use of AMOLED technology for future human spaceflight missions- both government-led and commercial. Under this SM, HI is responsible for doing optical performance evaluation, as well as temperature and touch screen studies. The NASA/JSC is responsible for performing environmental testing comprised of EMI, Thermal Vac, and radiation tests. Additionally, as part of the testing, limited optical data was acquired to assess performance as the display was subjected to the induced environments. The NASA will benefit from this engineering evaluation by understanding AMOLED suitability for future use in space as well as becoming a smarter buyer (or developer) of the technology. HI benefits from the environmental testing results by understanding its performance limitations/shortcomings to improve subsequent generations of AMOLED technology. Note that the AMOLED used in this test was not deSigned for the space environment but rather for commercial/industrial terrestrial applications.

Salazar, George A.

2013-01-01

144

Planet signatures in collisionally active debris discs: scattered light images  

NASA Astrophysics Data System (ADS)

Context. Planet perturbations have been often invoked as a potential explanation for many spatial structures that have been imaged in debris discs. So far this issue has been mostly investigated with pure N-body numerical models, which neglect the crucial effect collisions within the disc can have on the disc's response to dynamical perturbations. Aims: We numerically investigate how the coupled effect of collisions and radiation pressure can affect the formation and survival of radial and azimutal structures in a disc perturbed by a planet. We consider two different set-ups: a planet embedded within an extended disc and a planet exterior to an inner debris ring. One important issue we want to address is under which conditions a planet's signature can be observable in a collisionally active disc. Methods: We use our DyCoSS code, which is designed to investigate the structure of perturbed debris discs at dynamical and collisional steady-state, and derive synthetic images of the system in scattered light. The planet's mass and orbit, as well as the disc's collisional activity (parameterized by its average vertical optical depth ?0) are explored as free parameters. Results: We find that collisions always significantly damp planet-induced spatial structures. For the case of an embedded planet, the planet's signature, mostly a density gap around its radial position, should remain detectable in head-on images if Mplanet ? MSaturn. If the system is seen edge-on, however, inferring the presence of the planet is much more difficult, as only weak asymmetries remain in a collisionally active disc, although some planet-induced signatures might be observable under very favourable conditions. For the case of an inner ring and an external planet, planetary perturbations cannot prevent collision-produced small fragments from populating the regions beyond the ring. The radial luminosity profile exterior to the ring is in most cases close to the one it should have in the absence of the external planet. The most significant signature left by a Jovian planet on a circular orbit are precessing azimutal structures that can be used to indirectly infer its presence. For a planet on an eccentric orbit, we show that the ring becomes elliptic and that the well known pericentre glow effect is visible despite of collisions and radiation pressure, but that detecting such features in observed discs is not an unambiguous indicator of the presence of an outer planet. Movies are available in electronic form at http://www.aanda.org

Thebault, P.; Kral, Q.; Ertel, S.

2012-11-01

145

Effects of light intensity on activity in four sympatric anuran tadpoles.  

PubMed

Though light conditions are known to affect the development and anti-predation strategies of several aquatic species, relatively little is known about how different species react to light, or how light can affect these species during different points in their life-cycle. In this study, we used four sympatric anuran tadpoles (Bufo gargarizans, B. melanostictus, Pelophylax nigromaculatus and Microhyla fissipes) as animal system to examine species-specific activities of the underdoing different light intensity treatments, so as to better understand how they respond to light. We exposed four different species of tadpoles to 1660 and 14 lux light intensity treatments and then measured several parameters including development stage, body length and tail length, and as well as their basic activities. The results of this observation and analysis showed that the activities of tadpoles were significantly greater in B. gargarizans and B. melanostictus than in P. nigromaculatus and M. fissipes; and were also significantly greater during times of high light intensity as compared to during low light intensity. Moreover, the observed relationship between species and light intensity was significant. The activities of B. gargarizans and B. melanostictus tadpoles were greater in high light, while the activity of P. nigromaculatus tadpoles was greater in low light intensity, while M. fissipes tadpoles showed no differences in either low or high intensity light. Furthermore, the activities of B. gargarizans, B. melanostictus and M. fissipes tadpoles in terms of developmental stage, body size or tail length did not seem to differ with light intensity, but during early larval developmental period of P. nigromaculatus, the activity of tadpoles was negatively correlated with development stage, but irrelevant to either body size or tail length in different light intensities. These results lead us to conclude the observed activities of the four sympatric anuran tadpoles are closely correlated with their specific anti-predation strategies. PMID:25017754

Ding, Guo-Hua; Lin, Zhi-Hua; Zhao, Li-Hua; Fan, Xiao-Li; Wei, Li

2014-07-18

146

Light  

Microsoft Academic Search

A paperback version of the book first published in 1987. The author's objective in choosing the subject of light is to present it as one of these central themes and to follow it in many logical paths. These lead to the rest of the electromagnetic spectrum, to ultraviolet light, X-rays, and radio waves. They lead to the cosmic background radiation,

M. I. Sobel

1989-01-01

147

The impact on seaplane floats during landing  

NASA Technical Reports Server (NTRS)

In order to make a stress analysis of seaplane floats, and especially of the members connecting the floats with the fuselage, it is of great importance to determine the maximum pressure acting on the floats during landing. Here, the author gives a formula for maximum pressures during landing that permits one to apply experimental results to different bodies and different velocities. The author notes that the formula checks very well with experimental results.

Von Karman, TH

1929-01-01

148

Clustering of Floating Particles by Surface Waves  

Microsoft Academic Search

We study experimentally and theoretically how waves affect the distribution of particles floating on a liquid surface. According\\u000a to the Archimedes’ law the weight of floating particle is equal to the weight of displaced liquid. This law is not quite precise\\u000a for small floating objects. An additional force generating by surface tension pulls a hydrophilic particle deeper into the\\u000a water

Sergei Lukaschuk; Petr Denissenko; Gregory Falkovich

2006-01-01

149

Diet Light  

NSDL National Science Digital Library

In this quick activity, learners observe how the added sugar in a can of soda affects its density and thus, its ability to float in water. Learners explore this phenomenon by testing if two cans of soda (one regular, one diet or "sugar-free") float in a fish-tank filled with water. Use this activity to introduce learners to the concepts of density and water displacement. This resource also explains how atmospheric density plays a role in meteorology and includes thunderstorm safety tips.

Service, National W.

2012-06-26

150

Automatic recalibration of an active structured light vision system  

Microsoft Academic Search

A structured light vision system using pattern pro- jection is useful for robust reconstruction of three-dimensional ob- jects. One of the major tasks in using such a system is the calibra- tion of the sensing system. This paper presents a new method by which a two-degree-of-freedom structured light system can be au- tomatically recalibrated, if and when the relative pose

Y. F. Li; S. Y. Chen

2003-01-01

151

Floating full-color image with computer-generated alcove rainbow hologram  

NASA Astrophysics Data System (ADS)

We have investigated the floating full color image display with the computer-generated hologram (CGH). The floating image, when utilized as a 3D display, gives strong impression to the viewer. In our previous study, to change the CGH shape from the flat type to the half cylindrical type, the floating image from the output CGH has the nearly 180 degrees viewing angle. However, since the previous CGH does not have wavelength-selectivity, reconstructed image only has a single color. Also, the huge calculation amount of the fringe pattern is big problem. Therefore, we now propose the rainbow-type computer generated alcove hologram. To decrease the calculation amount, the rainbow hologram sacrifices the vertical parallax. Also, this hologram can reconstruct an image with white light. Compared with the previous study of the Fresnel type, the calculation speed becomes 165 times faster. After calculation, we print this hologram with a fringe printer, and evaluate reconstructed floating full color images. In this study, we introduce the computer-generated rainbow hologram into the floating image display. The rainbow hologram can reconstruct full color image with white light illumination. It can be recorded by using a horizontal slit to limit the vertical parallax. Therefore, the slit changes into the half cylindrical slit, the wide viewing angle floating image display can reconstruct full color image.

Yamaguchi, Takeshi; Yoshikawa, Hiroshi

2014-02-01

152

Synthesis and polymorphic control for visible light active titania nanoparticles  

NASA Astrophysics Data System (ADS)

Titania (TiO2) is useful for many applications in photocatalysis, antimicrobials, pigment, deodorization, and decomposition of harmful organics and undesirable compounds in the air and waste water under UV irradiation. Among the three phases of TiO2, Rutile, Anatase, and Brookite, studies have been more focused on the anatase and rutile phases. Pure brookite is the most difficult phase to prepare, even under hydrothermal conditions. Predominantly brookite phase TiO2 nanoparticles were prepared by the Water-based Ambient Condition Sol (WACS) process in our laboratory. The objectives of this research were to enhance visible light active (VLA) photocatalytic properties of polymorphic brookite TiO2 by minimizing the lattice defects and narrowing band gap of titania by nitrogen and/or carbon chromophone, and to investigate the deactivation, reusability, and regeneration of the VLA titania in order to design better titania catalysts for organic compound degradation applications. In order to study the influence of hydroxyl content on photocatalytic activities (PCAs) of polymorphic titania nanoparticles, the WACS samples were post-treated by a Solvent-based Ambient Condition Sol (SACS) process in sec-butanol (sec-BuOH). All samples were characterized for phase composition, surface area, hydroxyl contamination, and particle morphology by x-ray diffraction, N2 physisorption, FT-IR, solid state 1H NMR and scanning electron microscopy, and then compared to a commercial titania, Degussa P25. Evaluation of methyl orange (MO) degradation under UV irradiation results showed that the lower lattice hydroxyl content in SACS titania enhanced the PCA. As-prepared titania and SACS samples, which have similar surface areas and crystallinity, were compared in order to prove that the superior PCA came from the reduction in the lattice hydroxyl content. To enhance PCA and VLA properties of WACS, an alternative high boiling point polar solvent, N-methylpyrrolidone (NMP), was utilized in the SACS process at a higher treatment temperature to modify polymorphic titania nanoparticles. This SACS sample was called "SACS-NMP". SACS, using NMP as the solvent, could also extract lattice hydroxyls, and decorate nitrogen on the titania surface. The PCA of SACS-NMP was superior to that of SACS-sec-BuOH. Nitrogen incorporation of SACS-NMP titania was investigated by CHN analysis and x-ray photoelectron spectroscopy (XPS). VL absorbance for all samples was characterized by UV-Vis absorption spectrophotometry. PCA of MO degradation under UV and VL showed that SACS-NMP is a powerful treatment to enhance PCA by minimizing lattice hydroxyls and doping the titania surface with nitrogen. The effect of calcination conditions on SACS-NMP samples was also studied. The calcination conditions, especially the temperature and calcination atmosphere, have an influence on the BET surface area, crystallite size, titania phase content, and PCA under VL irradiation. SACS-NMP samples calcined in air at 200°C for 2 hours showed the best VL activated photocatalytic performance in this research. Additionally, the SACS-NMP sample exhibited superior VL properties to several available reference anatase titania samples. This could be explained as the effective charge separation by the intercrystalline electron transport from brookite to anatase grains complemented by strong VL absorption by the nitrogen species in NMP. The deactivation and regeneration of the VLA titania were investigated and compared to a commercial titania, Kronos VLP7000. PCA of the titania under VL for MO decolorization gradually decreased with increasing testing time and the number of runs. The cause of the deactivation was identified as the deposition of the decomposed MO or the carbonaceous deposit. Among the possible regeneration procedures for used SACS-NMP samples, methanol washing was shown to be the most effective up to ˜80% of the PCA recovery. Accordingly, the SACS-NMP samples could not be completely recovered since a regeneration process would possibly remove some of nitrogen species responsib

Kaewgun, Sujaree

153

Responses of Rubisco activation and deactivation rates to variations in growth-light conditions  

Microsoft Academic Search

Basil (Ocimum basilicum) and impatiens (Impatiens wallerana) were grown in sun, shade, or fluctuating light (15 min sun, 15 min shade) to examine the effects of growth-light conditions on the rates of light-induced Rubisco activation and deactivation. Rubisco activation and deactivation rates were determined from gas-exchange measurements of photosynthesis following a step increase in PFD. Rubisco deactivation rates were also

Jerriann Ernstsen; Ian E. Woodrow; Keith A. Mott

1997-01-01

154

14 CFR 23.753 - Main float design.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 false Main float design. 23.753 Section 23...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main...

2013-01-01

155

14 CFR 23.753 - Main float design.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 false Main float design. 23.753 Section 23...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main...

2012-01-01

156

14 CFR 23.753 - Main float design.  

...2014-01-01 false Main float design. 23.753 Section 23...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main...

2014-01-01

157

14 CFR 23.753 - Main float design.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 false Main float design. 23.753 Section 23...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main...

2011-01-01

158

14 CFR 23.753 - Main float design.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Main float design. 23.753 Section 23...DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS...COMMUTER CATEGORY AIRPLANES Design and Construction Floats and Hulls § 23.753 Main float design. Each seaplane main...

2010-01-01

159

SCIENCE, OPTICS & YOU GUIDEBOOK Module 4, Light and Colors, encompasses three activities that help students explore, investigate  

E-print Network

. Visible light as a form of energy is addressed in Activity 10. Activity 8: Light, Prisms, and the Rainbow the connection between light passing through a prism and how rainbows are formed. As with the other activities, including visible light as a form of energy. The following interactive web-based tutorials can be used

Weston, Ken

160

Phototropins and chloroplast activity in plant blue light signaling  

PubMed Central

In plants, phototropins 1 (phot1) and 2 (phot2) mediate chloroplast movement to blue light (BL). A recent report showed that phototropins (phot) are required for the expression of chloroplast genes in rice. The light-induced responses of phot1a rice mutants result in H2O2-mediated damage to chloroplast photosystems, indicating that phot-regulated responses might be associated with the other photoreceptor, such as cryptochrome (cry) BL receptor. This suggests diversification and specialization of photoreceptor signaling in plants. PMID:19820313

2009-01-01

161

Light Travel Time and the Size of Active Galaxies  

NSDL National Science Digital Library

Using real data from NASA's Fermi satellite, students determine the size and energy of an active galaxy flare region. This activity includes background information for teachers, student worksheets, procedures, adaptations, extensions, an assessment rubric, and related resources. This is activity 3 of 3 in the "Active Galaxies Educator's Guide."

162

Regulation of Transcription through Light-Activation and Light-Deactivation of Triplex-Forming Oligonucleotides in Mammalian Cells  

PubMed Central

Triplex-forming oligonucleotides (TFOs) are efficient tools to regulate gene expression through the inhibition of transcription. Here, nucleobase-caging technology was applied to the first temporal regulation of transcription through light-activated TFOs. Through site-specific incorporation of caged thymidine nucleotides, the TFO:DNA triplex formation is blocked, rendering the TFO inactive. However, after a brief UV irradiation, the caging groups are removed, activating the TFO, and leading to the inhibition of gene transcription. Furthermore, the synthesis and site-specific incorporation of caged deoxycytidine nucleotides within TFO inhibitor sequences was developed, and allows for the light-deactivation of TFO function and thus photochemical activation of gene expression. After UV-induced removal of the caging groups, the TFO forms a DNA dumbbell structure, rendering it inactive, releasing it from the DNA, and activating transcription. These are the first examples of light-regulated TFOs and their application in the photochemical activation and deactivation of gene expression. In addition, hairpin loop structures were found to significantly increase the efficacy of phosphodiester DNA-based TFOs in tissue culture. PMID:22540192

Govan, Jeane M.; Uprety, Rajendra; Hemphill, James; Lively, Mark O.

2012-01-01

163

Used float shoe recovered and tested  

Microsoft Academic Search

A cement float valve has been recovered after it was circulated through and cemented downhole. It was retrieved by coring as part of an investigation into a cementing failure. The float equipment was then analyzed for downhole performance. This is believed to be the first instance of intact recovery of full-scale cementing hardware after it has been cemented in place.

Colvard

1986-01-01

164

14 CFR 23.757 - Auxiliary floats.  

...and Hulls § 23.757 Auxiliary floats. Auxiliary floats must be arranged so that, when completely submerged in fresh water, they provide a righting moment of at least 1.5 times the upsetting moment caused by the seaplane or amphibian...

2014-01-01

165

A Variable Light Domain Fluorogen Activating Protein Homodimerizes to Activate Dimethylindole Red†  

PubMed Central

Novel fluorescent tools such as green fluorescent protein analogs and Fluorogen Activating Proteins (FAPs) are useful in biological imaging to track protein dynamics in real-time with low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (VH) and variable light (VL) domains covalently attached via a glycine and serine rich linker. Previously, we determined that the yeast surface clone, VH-VL M8, could bind and activate the fluorogen dimethylindole red (DIR), but that the fluorogen activation properties were localized to the M8VL domain. We report here that both NMR and X-ray diffraction methods indicate the M8VL forms non-covalent, anti-parallel homodimers that are the fluorogen activating species. The M8VL homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments of both VH-VL M8 and M8VL, led us to rationally design tandem, covalent homodimers of M8VL domains joined by a flexible linker that have a high affinity for DIR and good quantum yield. PMID:22390683

Senutovitch, Nina; Stanfield, Robyn L.; Bhattacharyya, Shantanu; Rule, Gordon S.; Wilson, Ian A.; Armitage, Bruce A.; Waggoner, Alan S.; Berget, Peter B.

2012-01-01

166

Floating plant dominance as a stable state  

PubMed Central

Invasion by mats of free-floating plants is among the most important threats to the functioning and biodiversity of freshwater ecosystems ranging from temperate ponds and ditches to tropical lakes. Dark, anoxic conditions under thick floating-plant cover leave little opportunity for animal or plant life, and they can have large negative impacts on fisheries and navigation in tropical lakes. Here, we demonstrate that floating-plant dominance can be a self-stabilizing ecosystem state, which may explain its notorious persistence in many situations. Our results, based on experiments, field data, and models, represent evidence for alternative domains of attraction in ecosystems. An implication of our findings is that nutrient enrichment reduces the resilience of freshwater systems against a shift to floating-plant dominance. On the other hand, our results also suggest that a single drastic harvest of floating plants can induce a permanent shift to an alternative state dominated by rooted, submerged growth forms. PMID:12634429

Scheffer, Marten; Szabo, Sandor; Gragnani, Alessandra; van Nes, Egbert H.; Rinaldi, Sergio; Kautsky, Nils; Norberg, Jon; Roijackers, Rudi M. M.; Franken, Rob J. M.

2003-01-01

167

LIGHT, a member of the TNF superfamily, activates Stat3 mediated by NIK pathway  

SciTech Connect

Stat3, a member of the signal transducers and activators of transcription (STAT) family, is a key signal transduction protein activated by numerous cytokines, growth factors, and oncoproteins that controls cell proliferation, differentiation, development, survival, and inflammation. Constitutive activation of Stat3 has been found frequently in a wide variety of human tumors and induces cellular transformation and tumor formation. In this study, we demonstrated that LIGHT, a member of tumor necrosis factor superfamily, activates Stat3 in cancer cells. LIGHT induces dose-dependent activation of Stat3 by phosphorylation at both the tyrosine 705 and serine 727 residues. The activation of Stat3 by LIGHT appears to be mediated by NIK phosphorylation. Expression of a kinase-inactive NIK mutant abolished LIGHT induced Stat3 activation. Overexpression of an active NIK induces Stat3 activation by phosphorylation at the both tyrosine 705 and serine 727 residues. Activation of Stat3 by NIK requires NIK kinase activity as showed by kinase assays. In addition, LIGHT increases the expression of Stat3 target genes including cyclin D1, survivin, and Bcl-xL, and stimulates human LNCaP prostate cancer cell growth in vitro which can be blocked by expression of a dominant-negative Stat3 mutant. Taken together, these results indicate that in addition to activating NF-{kappa}B/p52, LIGHT also activates Stat3. Activation of Stat3 together with activating non-canonical NF-{kappa}B/p52 signaling by LIGHT may maximize its effects on cellular proliferation, survival, and inflammation.

Nadiminty, Nagalakshmi [Departments of Medicine, Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Chun, Jae Yeon [Departments of Medicine, Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Hu, Yan [Departments of Medicine, Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Dutt, Smitha [Departments of Medicine, Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States); Lin, Xin [Department of Molecular Oncology, MD Anderson Cancer Center, Houston, TX 77030 (United States); Gao, Allen C. [Departments of Medicine, Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263 (United States)]. E-mail: allen.gao@roswellpark.org

2007-07-27

168

Substitution Mutations in the Myosin Essential Light Chain Lead to Reduced Actin-activated ATPase Activity Despite Stoichiometric  

E-print Network

Substitution Mutations in the Myosin Essential Light Chain Lead to Reduced Actin-activated ATPase Biology, Northwestern University Medical School, Chicago, Illinois 60611 Myosin essential light chain (ELC) wraps around an -helix that extends from the myosin head, where it is believed to play a structural

Chisholm, Rex L.

169

Floating light-activated microelectrical stimulators tested in the rat spinal cord This article has been downloaded from IOPscience. Please scroll down to see the full text article.  

E-print Network

cord. The power required to generate a threshold arm movement was investigated as the laser source [3]. These direct methods of wireless neural stimulation are not yet commonplace in neural prosthetic

170

Intermittent long-wavelength red light increases the period of daily locomotor activity in mice  

Microsoft Academic Search

BACKGROUND: We observed that a dim, red light-emitting diode (LED) triggered by activity increased the circadian periods of lab mice compared to constant darkness. It is known that the circadian period of rats increases when vigorous wheel-running triggers full-spectrum lighting; however, spectral sensitivity of photoreceptors in mice suggests little or no response to red light. Thus, we decided to test

John R Hofstetter; Amelia R Hofstetter; Amanda M Hughes; Aimee R Mayeda

2005-01-01

171

A novel control process of cyanobacterial bloom using cyanobacteriolytic bacteria immobilized in floating biodegradable plastic carriers  

Microsoft Academic Search

A process using a floating carrier for immobilization of cyanobacteriolytic bacteria, B.cereus N?14, was proposed to realize an effective in situ control of natural floating cyanobacterial blooms. The critical concentrations of the cyanobacteriolytic substance and B.cereus N?14 cells required to exhibit cyanobacteriolytic activity were investigated. The results indicated the necessity of cell growth to produce sufficiently high amounts of the

N. Nakamura; K. Nakano; N. Sugiura; M. Matsumura

2003-01-01

172

Implementation of a novel floating-image display system having a background of multiview integral images  

Microsoft Academic Search

A floating-image display technique, which can project two-dimensional images into a real space through a convex lens or a concave mirror, has been studied as a new approach for implementation of the next-generation three-dimensional (3D) display system. However, the conventional floating-image display system was implemented just by using active display devices such as LCD panel and it could provide only

Suk-Pyo Hong; Yong-Seok Oh; Dong-Hak Shin; Eun-Soo Kim

2007-01-01

173

Active control of light based on polarization-coupling cascading  

NASA Astrophysics Data System (ADS)

In this letter, we proposed a novel method for optical manipulation based on polarization-coupling cascading in MgO-doped periodically poled lithium niobate crystal. Polarization-coupling cascading, a series of energy exchanges between two orthogonally polarized beams close to phase matching condition, can also lead to phase shifts, in analogy with that in cascaded second-order nonlinearities. In addition, the parameters of light such as phase, amplitude, and group velocity can be modulated by changing the relative power ratio of the incident continuous wave beams. The phase control was demonstrated by Newton's rings experiment, which was in good agreement with the theoretical prediction.

Huo, Juan; Zheng, Yuanlin; Chen, Xianfeng

2014-10-01

174

WindWaveFloat Final Report  

SciTech Connect

Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

Alla Weinstein, Dominique Roddier, Kevin Banister

2012-03-30

175

DNA methyltransferase activity assay based on visible light-activated photoelectrochemical biosensor.  

PubMed

DNA methylation has important roles in gene regulation and relates to some diseases, especially cancers. Because DNA methylation is catalyzed by DNA methyltransferases (MTase), it is important to detect the activity of DNA MTase. In this work, we developed a novel visible light-activated photoelectrochemical (PEC) biosensor for DNA MTase activity assay, whereby bismuth oxyiodide (BiOI) nanoflake was synthesized as photoactive electrode material, M. SssI MTase as methylation reagent and methyl binding domain protein (MBD1 protein) as methylation recognition element. After cytosine methylation event occurred at the site of 5'-CG-3', it could be probed by MBD1 protein and this protein could be combined tightly with methylated cytosine, which would lead to a decreased photocurrent due to the hindrance towards electron donor transferring to electrode surface by huge-volume protein. The decreased photocurrent was proportional to M. SssI MTase concentration from 0.1 to 50 unit/mL with the detection limit of 0.035 unit/mL (S/N=3). This detection limit was lower than that in some previous reports. This PEC biosensor showed high selectivity and good reproducibility for M. SssI MTase assay. Moreover, this method was successfully applied also to screen DNA MTase inhibitors, indicating that this PEC biosensor could be an alternative platform in anti-cancer pharmaceuticals discovery. PMID:24141114

Zhou, Yunlei; Xu, Zhenning; Wang, Mo; Sun, Bing; Yin, Huanshun; Ai, Shiyun

2014-03-15

176

Photodynamic treatment with BPD-MA (verteporfin) activated with light within different spectral ranges  

Microsoft Academic Search

Benzoporphyrin derivative monoacid ring A [BPD-MA (verteporfin) or BPD], a second generation photosensitizer tested in clinical trials in combination with red light was compared for its PDT efficiency in vitro and in vivo upon activation with light in the UVA, blue and red spectral ranges. PDT efficiency, calculated based on the BPD absorption spectrum and spectral output of the different

Anna M. Richter; Ashok K. Jain; Alice J. Canaan; Robert D. Bower; Janice North; Guillermo O. Simkin; Julia G. Levy

1997-01-01

177

Remote control of molecular motors using light-activated gearshifting  

NASA Astrophysics Data System (ADS)

Engineering molecular motors with dynamically controllable properties will allow selective perturbation of mechanical processes in vivo and provide sophisticated components for directed nanoscale transport in vitro. We previously constructed myosin motors that respond to a change in [Ca++] by reversing their direction of motion along the polarized actin filament [1]. To expand the potential applications of controllable molecular motors, we have now developed myosins that shift gears in response to blue light illumination. Light is a versatile control signal that can be readily modulated in time and space, and is generally orthogonal to cellular signaling. Using structure-guided protein engineering, we have incorporated LOV photoreceptor domains into the lever arms of chimeric myosins, resulting in motors that robustly speed up, slow down, or switch directions upon illumination. These genetically encoded motors should be directly deployable inside living cells. Our successful designs include constructs based on two different myosin classes, and we show that optical velocity control can be implemented in motors that move at microns/sec speeds, enabling practical biological and bioengineering applications.[4pt] [1] Chen, L., Nakamura, M., Schindler,T.D., and Bryant Z. (2012). Nat. Nanotechnol. 7, 252-6.

Bryant, Zev

2013-03-01

178

Conformational changes in an ultrafast light-driven enzyme determine catalytic activity  

E-print Network

LETTERS Conformational changes in an ultrafast light-driven enzyme determine catalytic activity, switches the enzyme into an active state characterized by a high rate and quantum yield of formation changes associated with switching of an enzyme from an `inactive' to an `active' conformation9­11 . Here

van Stokkum, Ivo

179

Nitrate reductase activity in corn seedlings as affected by light and nitrate content of nutrient media  

Microsoft Academic Search

Young corn plants placed in complete darkness for 48 hours lost 90% of their nitrate reductase activity. The activity was quickly restored when the plants were returned to the light. In other experiments, corn plants were grown under artificial shade in the greenhouse. The nitrate reductase activity in these plants decreased roughly in proportion to the amount of shading. It

R. H. Hageman; D. Flesher

1960-01-01

180

Young Scientists Explore Light & Color. Book 12--Intermediate Level. A Good Apple Activity Book.  

ERIC Educational Resources Information Center

Designed to develop creativity in young learners, this book contains interdisciplinary activities which focus on the theme of light and color. Activity pages are provided that can serve as front and back covers of a student booklet and the suggested activities can be duplicated for insertion between the covers resulting in a booklet for each…

DeBruin, Jerry

181

GAS PHASE SELECTIVE PHOTOXIDATION OF ALCOHOLS USING LIGHT-ACTIVATED TITANIUM DIOXIDE AND MOLECULAR OXYGEN  

EPA Science Inventory

Gas Phase Selective Oxidation of Alcohols Using Light-Activated Titanium Dioxide and Molecular Oxygen Gas phase selective oxidations of various primary and secondary alcohols are studied in an indigenously built stainless steel up-flow photochemical reactor using ultravi...

182

Developing the ``Multiwavelength Astronomy: Galaxies in a Different Light'' Activity  

NASA Astrophysics Data System (ADS)

``Multiwavelength Astronomy'' is designed to lead high school students to understand astronomers' use of different wavelengths in studying the nature of galaxies. When developing the activity we followed the NASA-funded Virtual Design Center guidelines. With the project rationale and standards- alignment analysis completed, we surveyed high school students from several classes about their knowledge and interest in topics related to galaxy research. Their responses, and later pilot tests with secondary teachers and students, informed the development team's efforts. Topics included are the electromagnetic spectrum, false-color imaging, image resolution, Wien's law, and galaxy morphology. These were chosen to serve as prerequisites for future computer-intensive activities, which would involve students with data sets from the HST GEMS survey, one of the widest-area galaxy surveys conducted in two filters to date. Our description of the development process illustrates how we integrated topics of student interest into the activity while adhering to the design goal of incrementally augmenting student conceptual learning through a series of successive activities. Products for this activity include student and teacher guides, series of galaxy images in different wavelengths, a PowerPoint presentation, and sample materials for student assessment and evaluation of the activities.

Hemenway, M. K.; Jogee, S.; Fricke, K.; Worhatch, R.; Ruberg, L.

2008-06-01

183

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics...Floats and Hulls § 25.751 Main float buoyancy. Each main float must have— (a) A buoyancy of 80 percent in excess of that...

2012-01-01

184

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2011 CFR

... 2011-01-01 false Main float buoyancy. 23.751 Section 23.751 Aeronautics...Floats and Hulls § 23.751 Main float buoyancy. (a) Each main float must have— (1) A buoyancy of 80 percent in excess of the...

2011-01-01

185

14 CFR 29.751 - Main float buoyancy.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Main float buoyancy. 29.751 Section 29.751 Aeronautics...Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2011-01-01

186

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics...Floats and Hulls § 25.751 Main float buoyancy. Each main float must have— (a) A buoyancy of 80 percent in excess of that...

2011-01-01

187

14 CFR 27.751 - Main float buoyancy.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Main float buoyancy. 27.751 Section 27.751 Aeronautics...Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2012-01-01

188

14 CFR 27.751 - Main float buoyancy.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Main float buoyancy. 27.751 Section 27.751 Aeronautics...Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2011-01-01

189

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2012 CFR

... 2012-01-01 false Main float buoyancy. 23.751 Section 23.751 Aeronautics...Floats and Hulls § 23.751 Main float buoyancy. (a) Each main float must have— (1) A buoyancy of 80 percent in excess of the...

2012-01-01

190

14 CFR 29.751 - Main float buoyancy.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Main float buoyancy. 29.751 Section 29.751 Aeronautics...Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2012-01-01

191

14 CFR 29.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Main float buoyancy. 29.751 Section 29.751 Aeronautics...Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2010-01-01

192

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Main float buoyancy. 23.751 Section 23.751 Aeronautics...Floats and Hulls § 23.751 Main float buoyancy. (a) Each main float must have— (1) A buoyancy of 80 percent in excess of the...

2010-01-01

193

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics...Floats and Hulls § 25.751 Main float buoyancy. Each main float must have— (a) A buoyancy of 80 percent in excess of that...

2010-01-01

194

14 CFR 27.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Main float buoyancy. 27.751 Section 27.751 Aeronautics...Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2010-01-01

195

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics...Floats and Hulls § 25.751 Main float buoyancy. Each main float must have— (a) A buoyancy of 80 percent in excess of that...

2013-01-01

196

14 CFR 27.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Main float buoyancy. 27.751 Section 27.751 Aeronautics...Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2013-01-01

197

14 CFR 29.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Main float buoyancy. 29.751 Section 29.751 Aeronautics...Floats and Hulls § 29.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2013-01-01

198

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

... 2013-01-01 false Main float buoyancy. 23.751 Section 23.751 Aeronautics...Floats and Hulls § 23.751 Main float buoyancy. (a) Each main float must have— (1) A buoyancy of 80 percent in excess of the...

2013-01-01

199

14 CFR 25.751 - Main float buoyancy.  

...2014-01-01 2014-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics...Floats and Hulls § 25.751 Main float buoyancy. Each main float must have— (a) A buoyancy of 80 percent in excess of that...

2014-01-01

200

Program Converts VAX Floating-Point Data To UNIX  

NASA Technical Reports Server (NTRS)

VAX Floating Point to Host Floating Point Conversion (VAXFC) software converts non-ASCII files to unformatted floating-point representation of UNIX machine. This is done by reading bytes bit by bit, converting them to floating-point numbers, then writing results to another file. Useful when data files created by VAX computer must be used on other machines. Written in C language.

Alves, Marcos; Chapman, Bruce; Chu, Eugene

1996-01-01

201

Light pulses entrain the circadian activity rhythm of a diurnal rodent (Ammospermophilus leucurus).  

PubMed

Circadian rhythms of wheel-running activity of the antelope ground squirrel (Ammospermophilus leucurus) were entrained by light-dark cycles (LD: 100 1x vs total darkness) with periods (T) between ca 23.75 and 24.75 hr. Two 1-hr light pulses per cycle ('skeleton photoperiods') with T = 24.25 hr as well as one 1-hr light pulse per cycle with Ts of 23.75 and 24.25 hr were effective in entraining the circadian activity rhythms in at least 50% of the antelope ground squirrels. Phase and period responses to single 1-hr light pulses were measured which depend on the initial phase and period of the rhythm. It is concluded that discrete (phasic) light input contributes to the mechanism of entrainment to LD cycles in diurnal rodents. PMID:6661897

Pohl, H

1983-01-01

202

Tests find hammering, fluid cutting, erosion cause float shoe failures  

SciTech Connect

The results of a systematic test program to evaluate float equipment performance are presented. The testing has destroyed, over an eightmonth period, 160 float valves, float shoes and float collars. A new float valve design with greater resistance to failure has been developed as a result of the testing. New float collars and float shoes are expected to provide the operator with a failure rate of less than 1 1/2% when used within design limits and under normal cementing conditions. Further testing objectives include: extension of operating temperature limits to include deep well and geothermal conditions, and evaluation of the effects of more abrasive mud and cement systems.

Stringfellow, B.

1985-01-21

203

Fear of Floating and Social Welfare  

E-print Network

Fear of Floating and Social Welfare Demosthenes N. Tambakis? Faculty of Economics University of Cambridge May 2007 Abstract: This paper studies the welfare implications of financial sta- bility and inflation stabilization as distinct monetary policy...

Tambakis, Demosthenes N

204

Parametric design of floating wind turbines  

E-print Network

As the price of energy increases and wind turbine technology matures, it is evident that cost effective designs for floating wind turbines are needed. The next frontier for wind power is the ocean, yet development in near ...

Tracy, Christopher (Christopher Henry)

2007-01-01

205

Verification of floating-point software  

NASA Technical Reports Server (NTRS)

Floating point computation presents a number of problems for formal verification. Should one treat the actual details of floating point operations, or accept them as imprecisely defined, or should one ignore round-off error altogether and behave as if floating point operations are perfectly accurate. There is the further problem that a numerical algorithm usually only approximately computes some mathematical function, and we often do not know just how good the approximation is, even in the absence of round-off error. ORA has developed a theory of asymptotic correctness which allows one to verify floating point software with a minimum entanglement in these problems. This theory and its implementation in the Ariel C verification system are described. The theory is illustrated using a simple program which finds a zero of a given function by bisection. This paper is presented in viewgraph form.

Hoover, Doug N.

1990-01-01

206

Lighting  

SciTech Connect

EPAct covers a vast territory beyond lighting and, like all legislation, also contains numerous {open_quotes}favors,{close_quotes} compromises, and even some sleight-of-hand. Tucked away under Title XIX, for example, is an increase from 20% to 28% tax on gambling winnings, effective January 1, 1993 - apparently as a way to help pay for new spending listed elsewhere in the bill. Overall, it is a landmark piece of legislation, about a decade overdue. It remains to be seen how the Federal Government will enforce upgrading of state (or even their own) energy codes. There is no mention of funding for {open_quotes}energy police{close_quotes} in EPAct. Merely creating such a national standard, however, provides a target for those who sincerely wish to create an energy-efficient future.

Audin, L. [Columbia Univ., New York, NY (United States)

1994-12-31

207

Intermittent long-wavelength red light increases the period of daily locomotor activity in mice  

PubMed Central

Background We observed that a dim, red light-emitting diode (LED) triggered by activity increased the circadian periods of lab mice compared to constant darkness. It is known that the circadian period of rats increases when vigorous wheel-running triggers full-spectrum lighting; however, spectral sensitivity of photoreceptors in mice suggests little or no response to red light. Thus, we decided to test the following hypotheses: dim red light illumination triggered by activity (LEDfb) increases the circadian period of mice compared to constant dark (DD); covering the LED prevents the effect on period; and DBA2/J mice have a different response to LEDfb than C57BL6/J mice. Methods The irradiance spectra of the LEDs were determined by spectrophotometer. Locomotor activity of C57BL/6J and DBA/2J mice was monitored by passive-infrared sensors and circadian period was calculated from the last 10 days under each light condition. For constant dark (DD), LEDs were switched off. For LED feedback (LEDfb), the red LED came on when the mouse was active and switched off seconds after activity stopped. For taped LED the red LED was switched on but covered with black tape. Single and multifactorial ANOVAs and post-hoc t-tests were done. Results The circadian period of mice was longer under LEDfb than under DD. Blocking the light eliminated the effect. There was no difference in period change in response to LEDfb between C57BL/6 and DBA/2 mice. Conclusion An increase in mouse circadian period due to dim far-red light (1 lux at 652 nm) exposure was unexpected. Since blocking the light stopped the response, sound from the sensor's electronics was not the impetus of the response. The results suggest that red light as background illumination should be avoided, and indicator diodes on passive infrared motion sensors should be switched off. PMID:15927074

Hofstetter, John R; Hofstetter, Amelia R; Hughes, Amanda M; Mayeda, Aimee R

2005-01-01

208

Notes 11. High pressure floating ring seals  

E-print Network

as a hydrodynamic plain journal bearing. That is, the oil seal ring becomes a load path. Engineering facts about floating ring oil seals ? The spring preload force prevents seal wear at low rotational speeds by impeding seal (carbon ring... as a hydrodynamic plain journal bearing. That is, the oil seal ring becomes a load path. Engineering facts about floating ring oil seals ? The spring preload force prevents seal wear at low rotational speeds by impeding seal (carbon ring...

San Andres, Luis

2009-01-01

209

Gas transfer in floating-leaved plants  

Microsoft Academic Search

Pressurized gas transport with flow rates of 1.1 to 1.81 gas h-1 plant-1 have been detected in the floating-leaved aquatic macrophyte Euryale ferox on sunny days. The younger leaves gave the highest pressurization, but the gas flow was initiated mainly by the middle-aged leaves of the plants. The gas through-flow was shown to be highly beneficial for floating-leaved plants. It

W. Große; C. Bauch

1991-01-01

210

Floating Bodies of Equilibrium. Explicit Solution  

E-print Network

Explicit solutions of the two-dimensional floating body problem (bodies that can float in all positions) for relative density rho different from 1/2 and of the tire track problem (tire tracks of a bicycle, which do not allow to determine, which way the bicycle went) are given, which differ from circles. Starting point is the differential equation given in archive physics/0205059 and Studies in Appl. Math. 111 (2003) 167-183.

Franz Wegner

2006-03-20

211

46 CFR 180.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2013 CFR

...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2013-10-01

212

46 CFR 180.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2012 CFR

...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2012-10-01

213

46 CFR 180.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2010 CFR

...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2010-10-01

214

46 CFR 180.137 - Stowage of life floats and buoyant apparatus.  

Code of Federal Regulations, 2011 CFR

...be of a dark color or of a type certified to be resistant to deterioration from ultraviolet light; and (3) If metal, be corrosion resistant. (d) If the life float or buoyant apparatus does not have a painter attachment fitting, a...

2011-10-01

215

Floating marine debris surface drift: Convergence and accumulation toward the South Pacific subtropical gyre  

E-print Network

Floating marine debris (FMD) and other marine pollution threa- ten the livelihood of coastal communities. Coastlines are strewn with a myriad of light-weight plastic bags and other debris, mar- ring the paradise or being caught in plastic bags and other debris (Wilks, 2006). Despite control measures, the amount

Taillandier, Vincent

216

Effectiveness of Mechanical Aerationin Floating Aquatic Macrophyte-Based Wastewater Treatment Systems  

E-print Network

Effectiveness of Mechanical Aerationin Floating Aquatic Macrophyte-Based Wastewater Treatment to evaluate its effect on wastewater treatment effi- ciency andplantgrowth. Light aeration (0.003 and0.021Lnr2 tanks. Heavy aeration (1.03 and 3.53 L nr2 min-1 ) raised wastewater dissolved oxygen(DO) concentrations

Florida, University of

217

A device to improve the SNR of the measurement of the positional floating reference point  

NASA Astrophysics Data System (ADS)

Previous studies have preliminarily validated the floating reference method and shown that it has the potential to improve the accuracy of non-invasive blood glucose sensing by Near-Infrared Spectroscopy. In order to make this method practical, it is necessary to precisely verify and measure the existence and variation features of the positional floating reference point. In this talk, a device which can precisely verify and measure the positional floating reference point is built. Since the light intensity of diffuse reflectance from the tested sample is very weak, a multipath detecting fibers system was built to improve signal-to-noise ratio. In this system, the fibers encircle the light source fiber which is regarded as the reference center of detecting fibers while they are moving. In addition, the position of each fiber is accurately controlled by manual translation stage to keep all detecting fibers always in the same radius around light source fiber. This ensures that received signal is coming from the same radial distance of light source. The variation of signal-to-noise ratio along with the different radial distance was investigated based on experiments. Results show that the application of this device could improve signal-to-noise ratio, and provide a new experimental method for the further study of positional floating reference point.

Jiang, Jingying; Rong, Xuzheng; Zhang, Hao; Xu, Kexin

2013-02-01

218

A multi-precision floating-point adder  

Microsoft Academic Search

This paper presents a multi-precision floating-point adder that can perform a high-precision floating-point addition, or multiple low-precision floating-point additions in parallel. The proposed design eliminates time consuming format conversion operations when it is operating in low-precision modes. The proposed multi-precision floating-point adder has delay approximately equal to a standard double-precision floating-point adder.

M. M. Ozbilen; M. Gok

2008-01-01

219

Stimulation of innate immune cells by light-activated TLR7/8 agonists.  

PubMed

The innate immune response is controlled, in part, by the synergistic interaction of multiple Toll-like receptors (TLRs). This multi-receptor cooperation is responsible for the potent activity of many vaccines, but few tools have been developed to understand the spatio-temporal elements of TLR synergies. In this Communication, we present photo-controlled agonists of TLR7/8. By strategically protecting the active agonist moiety based on an agonist-bound crystal structure, TLR activity is suppressed and then regained upon exposure to light. We confirmed NF-?B production upon light exposure in a model macrophage cell line. Primary cell activity was confirmed by examining cytokine and cell surface marker production in bone-marrow-derived dendritic cells. Finally, we used light to activate dendritic cell sub-populations within a larger population. PMID:25029205

Ryu, Keun Ah; Stutts, Lalisa; Tom, Janine K; Mancini, Rock J; Esser-Kahn, Aaron P

2014-08-01

220

Visible-Light-Induced Bactericidal Activity of a Nitrogen-Doped Titanium Photocatalyst against Human Pathogens  

PubMed Central

The antibacterial activity of photocatalytic titanium dioxide (TiO2) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO2 and carbon-doped TiO2 substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO2 substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO2 substrates than by pure TiO2 substrates. These findings suggest that nitrogen-doped TiO2 has potential application in the development of alternative disinfectants for environmental and medical usages. PMID:16957236

Wong, Ming-Show; Chu, Wen-Chen; Sun, Der-Shan; Huang, Hsuan-Shun; Chen, Jiann-Hwa; Tsai, Pei-Jane; Lin, Nien-Tsung; Yu, Mei-Shiuan; Hsu, Shang-Feng; Wang, Shih-Lien; Chang, Hsin-Hou

2006-01-01

221

Daily activity and light exposure levels for five species of lemurs at the Duke Lemur Center.  

PubMed

Light is the primary synchronizer of all biological rhythms, yet little is known about the role of the 24-hour luminous environment on nonhuman primate circadian patterns, making it difficult to understand the photic niche of the ancestral primate. Here we present the first data on proximate light-dark exposure and activity-rest patterns in free-ranging nonhuman primates. Four individuals each of five species of lemurs at the Duke Lemur Center (Eulemur mongoz, Lemur catta, Propithecus coquereli, Varecia rubra, and Varecia variegata variegata) were fitted with a Daysimeter-D pendant that contained light and accelerometer sensors. Our results reveal common as well as species-specific light exposure and behavior patterns. As expected, all five species were more active between sunrise and sunset. All five species demonstrated an anticipatory increase in their pre-sunrise activity that peaked at sunrise with all but V. rubra showing a reduction within an hour. All five species reduced activity during mid-day. Four of the five stayed active after sunset, but P. coquereli began reducing their activity about 2 hours before sunset. Other subtle differences in the recorded light exposure and activity patterns suggest species-specific photic niches and behaviors. The eventual application of the Daysimeter-D in the wild may help to better understand the adaptive evolution of ancestral primates. PMID:24318943

Rea, Mark S; Figueiro, Mariana G; Jones, Geoffrey E; Glander, Kenneth E

2014-01-01

222

Orexinergic signaling mediates light-induced neuronal activation in the dorsal raphe nucleus  

PubMed Central

Seasonal affective disorder (SAD), a major depressive disorder recurring in the fall and winter, is caused by the reduction of light in the environment, and its depressive symptoms can be alleviated by bright light therapy. Both circadian and monoaminergic systems have been implicated in the etiology of SAD. However, the underlying neural pathways through which light regulates mood are not well understood. The present study utilized a diurnal rodent model, Arvicanthis niloticus, to explore the neural pathways mediating the effects of light on brain regions involved in mood regulation. Animals kept in constant darkness received light exposure in early subjective day, the time when light therapy is usually applied. The time course of neural activity following light exposure was assessed using Fos as a marker in the following brain regions/cells: the suprachiasmatic nucleus (SCN), orexin neurons in the perifornical-lateral hypothalamic area (PF-LHA) and the dorsal raphe nucleus (DRN). A light-induced increase in Fos expression was observed in orexin neurons and the DRN, but not in the SCN. As the DRN is densely innervated by orexinergic inputs, the involvement of orexinergic signaling in mediating the effects of light on the DRN was tested in the second experiment. The animals were injected with the selective orexin receptor type 1 (OXR1) antagonist SB-334867 prior to the light exposure. The treatment of SB-334867 significantly inhibited the Fos induction in the DRN. The results collectively point to the role of orexin neurons in mediating the effects of light on the mood-regulating monoaminergic areas, suggesting an orexinergic pathway that underlies light-dependent mood fluctuation and the beneficial effects of light therapy. PMID:22710065

Adidharma, Widya; Leach, Greg; Yan, Lily

2012-01-01

223

Manipulating particles in microfluidics by floating electrodes.  

PubMed

Various particle manipulations including enrichment, movement, trapping, separation, and focusing by floating electrodes attached to the bottom wall of a straight microchannel under an imposed DC electric field have been experimentally demonstrated. In contrast to a dielectric microchannel possessing a nearly uniform surface charge (or ? potential), the metal strip (floating electrode) is polarized under the imposed electric field, resulting in a nonuniform distribution of the induced surface charge with a zero net surface charge along the floating electrode's surface, and accordingly induced-charge electroosmotic flow near the metal strip. The induced induced-charge electroosmotic flow can be regulated by controlling the strength of the imposed electric field and affects both the hydrodynamic field and the particle's motion. By using a single floating electrode, charged particles could be locally concentrated in a section of the channel or in an end-reservoir and move toward either the anode or the cathode by controlling the strength of the imposed electric field. By using double floating electrodes, negatively charged particles could be concentrated between the floating electrodes, subsequently squeezed to a stream flowing in the center region of the microchannel toward the cathodic reservoir, which can be used to focus particles. PMID:20945412

Yalcin, Sinan E; Sharma, Ashutosh; Qian, Shizhi; Joo, Sang W; Baysal, Oktay

2010-11-01

224

Light-Intensity Physical Activity and Cardiometabolic Biomarkers in US Adolescents  

PubMed Central

Background The minimal physical activity intensity that would confer health benefits among adolescents is unknown. The purpose of this study was to examine the associations of accelerometer-derived light-intensity (split into low and high) physical activity, and moderate- to vigorous-intensity physical activity with cardiometabolic biomarkers in a large population-based sample. Methods The study is based on 1,731 adolescents, aged 12–19 years from the 2003/04 and 2005/06 National Health and Nutrition Examination Survey. Low light-intensity activity (100–799 counts/min), high light-intensity activity (800 counts/min to <4 METs) and moderate- to vigorous-intensity activity (?4 METs, Freedson age-specific equation) were accelerometer-derived. Cardiometabolic biomarkers, including waist circumference, systolic blood pressure, diastolic blood pressure, HDL-cholesterol, and C-reactive protein were measured. Triglycerides, LDL- cholesterol, insulin, glucose, and homeostatic model assessments of ?-cell function (HOMA-%B) and insulin sensitivity (HOMA-%S) were also measured in a fasting sub-sample (n?=?807). Results Adjusted for confounders, each additional hour/day of low light-intensity activity was associated with 0.59 (95% CI: 1.18–0.01) mmHG lower diastolic blood pressure. Each additional hour/day of high light-intensity activity was associated with 1.67 (2.94–0.39) mmHG lower diastolic blood pressure and 0.04 (0.001–0.07) mmol/L higher HDL-cholesterol. Each additional hour/day of moderate- to vigorous-intensity activity was associated with 3.54 (5.73–1.35) mmHG lower systolic blood pressure, 5.49 (1.11–9.77)% lower waist circumference, 25.87 (6.08–49.34)% lower insulin, and 16.18 (4.92–28.53)% higher HOMA-%S. Conclusions Time spent in low light-intensity physical activity and high light-intensity physical activity had some favorable associations with biomarkers. Consistent with current physical activity recommendations for adolescents, moderate- to vigorous-intensity activity had favorable associations with many cardiometabolic biomarkers. While increasing MVPA should still be a public health priority, further studies are needed to identify dose-response relationships for light-intensity activity thresholds to inform future recommendations and interventions for adolescents. PMID:23951157

Carson, Valerie; Ridgers, Nicola D.; Howard, Bethany J.; Winkler, Elisabeth A. H.; Healy, Genevieve N.; Owen, Neville; Dunstan, David W.; Salmon, Jo

2013-01-01

225

The twilight zone: ambient light levels trigger activity in primitive ants  

PubMed Central

Many animals become active during twilight, a narrow time window where the properties of the visual environment are dramatically different from both day and night. Despite the fact that many animals including mammals, reptiles, birds and insects become active in this specific temporal niche, we do not know what cues trigger this activity. To identify the onset of specific temporal niches, animals could anticipate the timing of regular events or directly measure environmental variables. We show that the Australian bull ant, Myrmecia pyriformis, starts foraging only during evening twilight throughout the year. The onset occurs neither at a specific temperature nor at a specific time relative to sunset, but at a specific ambient light intensity. Foraging onset occurs later when light intensities at sunset are brighter than normal or earlier when light intensities at sunset are darker than normal. By modifying ambient light intensity experimentally, we provide clear evidence that ants indeed measure light levels and do not rely on an internal rhythm to begin foraging. We suggest that the reason for restricting the foraging onset to twilight and measuring light intensity to trigger activity is to optimize the trade-off between predation risk and ease of navigation. PMID:20129978

Narendra, Ajay; Reid, Samuel F.; Hemmi, Jan M.

2010-01-01

226

Floating Ice-Algal Aggregates below Melting Arctic Sea Ice  

PubMed Central

During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded within the mucous matrix. Aggregates maintained buoyancy and accumulated just above a strong pycnocline that separated meltwater and seawater layers. We were able, for the first time, to obtain quantitative abundance and biomass estimates of these aggregates. Although their biomass and production on a square metre basis was small compared to ice-algal blooms, the floating ice-algal aggregates supported high levels of biological activity on the scale of the individual aggregate. In addition they constituted a food source for the ice-associated fauna as revealed by pigments indicative of zooplankton grazing, high abundance of naked ciliates, and ice amphipods associated with them. During the Arctic melt season, these floating aggregates likely play an important ecological role in an otherwise impoverished near-surface sea ice environment. Our findings provide important observations and measurements of a unique aggregate-based habitat during the 2012 record sea ice minimum year. PMID:24204642

Assmy, Philipp; Ehn, Jens K.; Fernandez-Mendez, Mar; Hop, Haakon; Katlein, Christian; Sundfjord, Arild; Bluhm, Katrin; Daase, Malin; Engel, Anja; Fransson, Agneta; Granskog, Mats A.; Hudson, Stephen R.; Kristiansen, Svein; Nicolaus, Marcel; Peeken, Ilka; Renner, Angelika H. H.; Spreen, Gunnar; Tatarek, Agnieszka; Wiktor, Jozef

2013-01-01

227

Relative Dispersion of isobaric RAFOS Floats off Central California: Comparative Analysis of Estimation Techniques  

NASA Astrophysics Data System (ADS)

Dynamical regimes in the California Undercurrent and ocean interior off Central California are controlled by rich mesoscale activity, including eddies, filaments and turbulent jets. A unique dataset of 56 isobaric RAFOS floats was used to analyze relative dispersion in the region. The floats were launched in pairs and triads at 150- -600 m between 1993 and 2003 (http://www.oc.nps.navy.mil/npsRAFOS/). The launch design allowed us to identify about forty float pairs in several classes of initial separation distance. Taking into consideration the anisotropic nature of the California Undercurrent, alongshore and cross-shore separations were calculated for the identified pairs of float trajectories. We applied different techniques, both asymptotic and non-asymptotic, to estimate relative dispersion of the RAFOS floats. In addition to the probability distribution function of the mean square separation and its second- order moments, higher order moments were also considered to understand how much intermittency influence float dispersion. In addition to averaging distances at fixed times, two alternative approaches based on averaging times at fixed distance were tried, the finite size Lyapunov exponent and the parametrical exit time statistics. The latter was estimated both theoretically and using float sampling through the probability weighted moments. Statistical significance of the results as well as possible biases of the estimates due to horizontal and vertical shears were investigated. Different techniques give, in general, different dispersion regimes with power exponents varying between 0.5 and 2. Most differences occurred for the kurtosis and skewness at the initial stage for float pairs with small separation. The focus here was on finite sample size effects and an empirical criterion for evaluating the impact of sample size.

Margolina, T.; Collins, C. A.; Ivanov, L. M.; Hsieh, C.

2006-12-01

228

Determination of Energies of Intense Light Ion Beams by the Boron-Nitride Nuclear Activation Method  

Microsoft Academic Search

A technique capable of determining proton energies below 1 MeV by the Boron-Nitride (BN) nuclear activation method is described. This method is convenient and can be used even in a gas plasma. This situation often occures in a light ion beam transport experiment for particle beam fusion research. Activation results were compared with ion energies obtained from biased charge collectors.

Tetsu Ozaki; Shuji Miyamoto; Kazuo Imasaki; Ichiro Chihara; Sadao Nakai; Chiyoe Yamanaka

1982-01-01

229

Mechanisms of photoswitch conjugation and light activation of an ionotropic glutamate receptor  

E-print Network

Mechanisms of photoswitch conjugation and light activation of an ionotropic glutamate receptor Pau linker. We describe here the properties of a glutamate photoswitch that controls an ion channel in cells to the activating state places a tethered glutamate at a high (millimolar) effective local concentration near

Trauner, Dirk

230

Effects of temperature and photosynthetic inhibitors on light activation of C4-phosphoenolpyruvate carboxylase  

Microsoft Academic Search

Phosphoenolpyruvate carboxylase from leaves of the C4 plant Setaria verticillata (L.) Beauv. is activated by light; day levels of activity are reached after 30 minutes of illumination. Photoactivation is prevented by inhibitors of photosynthetic electron flow or of photophosphorylation and by D,L-glyceraldehyde, which inhibits the reductive pentose phosphate pathway.

Y. Samaras; Y. Manetas; N. A. Gavalas

1988-01-01

231

Modulation of Chloroplast Fructose-1,6-bisphosphatase Activity by Light 1  

PubMed Central

Inhibitor experiments indicate that light effect mediatorII which is reductively activated by transfer of electrons from the photosynthetic electron transport system at or beyond ferredoxin, is involved in activation by light of fructose-1,6-bisphosphatase in the pea plant. Activation proceeds optimally when the pH is low and Mg2+ is 10 millimolar. Modulation by light results in increases in maximal velocity, apparently as a result of changes in enzyme conformation. Pea leaf thylakoids are effective in modulating the activity of glyceraldehyde-3-phosphate dehydrogenase but not of fructose-1,6-bisphosphatase or glucose-6-phosphate dehydrogenase in Kalanchoë stromal extracts. There is apparently species specificity for modulation of some, but not all, of the modulatable enzymes. PMID:16660995

Anderson, Louise E.; Chin, Hae-Min; Gupta, Vimal K.

1979-01-01

232

Effects of special blue fluorescent light on hepatic mixed-function oxidase activity in the rat  

SciTech Connect

Phototherapy has been widely used in the treatment of neonatal hyperbilirubinemia. Recent reports, however, have indicated that fluorescent light may be toxic and mutagenic to mammalian cells. these findings suggest possible long-term side effects with the use of phototherapy. This study was undertaken to determine the effects of phototherapy on hepatic microsomal enzyme activity. The exposure of Sprague-Dawley and Gunn rats to special blue fluorescent light at an average irradiance of 1,200 microW/cm2 resulted in no significant changes in liver microsomal enzyme activity for aniline hydroxylase, p-nitroanisole-O-demethylase, ethylmorphine-N-demethylase, cytochrome c reductase or the quantity of cytochrome P-450. A significant decrease in aniline hydroxylase and p-nitroanisole-O-demethylase activity was observed when liver microsomes were exposed in vitro to special blue fluorescent light. Photoactivated bilirubin did not effect the activity of the mixed-function oxidase enzymes measured under the conditions of this study.

Davis, D.R.; Yeary, R.A.; Randall, G.

1981-01-01

233

Implementation of a novel night float call system: resident satisfaction and quality of life  

PubMed Central

Background Compliance with Professional Association of Internes and Residents of Ontario duty hour guidelines has been problematic at our institution. To facilitate orthopedic residents’ ability to go home postcall without significant disruption of ongoing clinical activities, a novel call system was adopted at our tertiary care centre. We sought to evaluate the satisfaction and quality of life of orthopaedic residents with that system. Methods We administered questionnaires to on-service residents. These included the Short Form–36 questionnaire and others addressing topics including education, stress, work-related problems and miscellaneous concerns. Results Seventeen residents were surveyed: 6 who had just completed a night float rotation, and 11 who were on a regular orthopedic service rotation while the night float system was in place. Quality of life was similar between residents on the night float block and those on the standard rotation; it was also similar to age-matched Canadian normative data. Eighty-nine percent of residents agreed that the presence of the night float rotation improved their quality of life on standard rotations, and 100% felt that their education was improved on standard rotations by having the night float system in place. Conclusion This call system results in improved resident quality of life and widespread overall satisfaction, and may be considered as a viable alternative to traditional call formats. Follow-up data as more residents experience the night float block will be valuable. PMID:24461221

Mann, Stephen M.; Borschneck, Daniel P.; Harrison, Mark M.

2014-01-01

234

Implementation of a novel floating-image display system having a background of multiview integral images  

NASA Astrophysics Data System (ADS)

A floating-image display technique, which can project two-dimensional images into a real space through a convex lens or a concave mirror, has been studied as a new approach for implementation of the next-generation three-dimensional (3D) display system. However, the conventional floating-image display system was implemented just by using active display devices such as LCD panel and it could provide only a real plane image in space to an observer comparing with other 3D display systems having different perspectives. For practical application of a floating-image display system to 3D display systems, multi-layered display structure might be required to present multi-depth images in space. In this paper, a novel floating-image display system composed of two plane images with different depth by use of a half mirror is proposed. One plane image of an object is provided with the conventional floating-image display system to present and the other plane image of a background is provided with the integral imaging technique. Therefore, the proposed display system can provide high-resolution floating images with background images having different perspectives to observers. To show the usefulness of the proposed system, some experiments are carried out and the results are presented as well.

Hong, Suk-Pyo; Oh, Yong-Seok; Shin, Dong-Hak; Kim, Eun-Soo

2007-09-01

235

An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching  

Microsoft Academic Search

This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical\\u000a region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated\\u000a by three different light sources. The samples were randomly divided into 3 groups (n = 15), according to the catalyst light

W. Kabbach; D. M. Zezell; M. C. Bandéca; T. M. Pereira; M. F. Andrade

2010-01-01

236

Light activates binding of membrane proteins to chloroplast RNAs in Chlamydomonas reinhardtii  

Microsoft Academic Search

Several membrane proteins were previously shown to bind to the 5' leader of the chloroplast psbC mRNA in the unicellular eukaryotic alga Chlamydomonas reinhardtii. This study showed that these proteins have affinity for AU-rich RNAs, as determined by competition experiments. In addition, their binding activities are enhanced 13–15-fold by light, and a 46 kDa protein is activated within 1–10 min. This activation

William Zerges; Shengwu Wang; Jean-David Rochaix

2002-01-01

237

Characterization of a light-dependent glutamate synthase activity in Chlamydomonas reinhardtii  

Microsoft Academic Search

Photosynthetically active vesicles prepared from Chlamydomonas reinhardtii retained a light-dependent glutamate synthase activity which was highly specific for 2-oxoglutarate (Km=2.1 mM) and L-glutamine (Km=0.9 mM) as amido group acceptor and donor respectively. This activity was inhibited by azaserine, p-hydroxymercuribenzoate and 3-(p-chlorophenyl)-1,1-dimethyl urea.

Antonio J. Márquez; M. Angeles Serra; José M. Vega

1987-01-01

238

Light-activation through indirect ceramic restorations: does the overexposure compensate for the attenuation in light intensity during resin cement polymerization?  

PubMed Central

Objectives This study evaluated the effects of light exposure through simulated indirect ceramic restorations (SICR) on hardness (KHN) of dual-cured resin cements (RCs), immediately after light-activation and 24 h later. Material and Methods Three dual-cured RCs were evaluated: eco-Link (Ivoclar Vivadent), Rely X ARC (3M eSPe), and Panavia F (Kuraray Medical Inc.). The RCs were manipulated in accordance to the manufacturers’ instructions and were placed into cylindrical acrylic matrixes (1-mm-thick and 4-mm diameter). The RC light-activation (Optilux 501; Demetron Kerr) was performed through a glass slide for 120 s (control group), or through 2-mm or 4-mm thick SICRs (IPS empress II; Ivoclar Vivadent). The specimens were submitted to KHN analysis immediately and 24 h after light-activation. The data obtained at the 2 evaluation intervals were submitted to 2-way ANOVA repeated measures and post-hoc Tukey’s test (pre-set alpha of 5%). Results Lower KHN was observed when light-activation was performed through SICRs for eco-Link at all evaluation intervals and for Rely X ARC 24 h later. For Panavia F, no significant difference in KHN was observed between control and experimental groups, regardless of evaluation interval. Most groups exhibited higher KHN after 24 h than immediately after light-activation, with the exception of Rely X ARC light-activated through SICR, as no significant difference in KHN was found between evaluation intervals. Conclusion Light overexposure did not compensate for light intensity attenuation due to the presence of SICR when Rely X and eco-Link were used. Although hardness of such RCs increased over a 24-h interval, the RCs subjected to light overexposure did not reach the hardness values exhibited after direct light exposure. PMID:21437465

BUENO, Albano Luis Novaes; ARRAIS, Cesar Augusto Galvão; JORGE, Ana Carolina Tedesco; REIS, Andre Figueiredo; AMARAL, Cristiane Mariote

2011-01-01

239

Floating seal system for rotary devices  

DOEpatents

This invention relates to a floating seal system for rotary devices to reduce gas leakage around the rotary device in a duct and across the face of the rotary device to an adjacent duct. The peripheral seal bodies are made of resilient material having a generally U-shaped cross section wherein one of the legs is secured to a support member and the other of the legs forms a contacting seal against the rotary device. The legs of the peripheral seal form an extended angle of intersection of about 10.degree. to about 30.degree. in the unloaded condition to provide even sealing forces around the periphery of the rotary device. The peripheral seal extends around the periphery of the support member except where intersected by radial seals which reduce gas leakage across the face of the rotary device and between adjacent duct portions. The radial seal assembly is fabricated from channel bars, the smaller channel bar being secured to the divider of the support member and a larger inverted rigid floating channel bar having its legs freely movable over the legs of the smaller channel bar forming therewith a tubular channel. A resilient flexible tube is positioned within the tubular channel for substantially its full length to reduce gas leakage across the tubular channel. A spacer extends beyond the face of the floating channel near each end of the floating channel a distance to provide desired clearance between the floating channel and the face of the rotary device.

Banasiuk, Hubert A. (Chicago, IL)

1983-01-01

240

Battery charging in float vs. cycling environments  

SciTech Connect

In lead-acid battery systems, cycling systems are often managed using float management strategies. There are many differences in battery management strategies for a float environment and battery management strategies for a cycling environment. To complicate matters further, in many cycling environments, such as off-grid domestic power systems, there is usually not an available charging source capable of efficiently equalizing a lead-acid battery let alone bring it to a full state of charge. Typically, rules for battery management which have worked quite well in a floating environment have been routinely applied to cycling batteries without full appreciation of what the cycling battery really needs to reach a full state of charge and to maintain a high state of health. For example, charge target voltages for batteries that are regularly deep cycled in off-grid power sources are the same as voltages applied to stand-by systems following a discharge event. In other charging operations equalization charge requirements are frequently ignored or incorrectly applied in cycled systems which frequently leads to premature capacity loss. The cause of this serious problem: the application of float battery management strategies to cycling battery systems. This paper describes the outcomes to be expected when managing cycling batteries with float strategies and discusses the techniques and benefits for the use of cycling battery management strategies.

COREY,GARTH P.

2000-04-20

241

Light-regulated phosphorylation of maize phosphoenolpyruvate carboxykinase plays a vital role in its activity.  

PubMed

Phosphoenolpyruvate carboxykinase (PEPCK)-the major decarboxylase in PEPCK-type C4 plants-is also present in appreciable amounts in the bundle sheath cells of NADP-malic enzyme-type C4 plants, such as maize (Zea mays), where it plays an apparent crucial role during photosynthesis (Wingler et al., in Plant Physiol 120(2):539-546, 1999; Furumoto et al., in Plant Mol Biol 41(3):301-311, 1999). Herein, we describe the use of mass spectrometry to demonstrate phosphorylation of maize PEPCK residues Ser55, Thr58, Thr59, and Thr120. Western blotting indicated that the extent of Ser55 phosphorylation dramatically increases in the leaves of maize seedlings when the seedlings are transferred from darkness to light, and decreases in the leaves of seedlings transferred from light to darkness. The effect of light on phosphorylation of this residue is opposite that of the effect of light on PEPCK activity, with the decarboxylase activity of PEPCK being less in illuminated leaves than in leaves left in the dark. This inverse relationship between PEPCK activity and the extent of phosphorylation suggests that the suppressive effect of light on PEPCK decarboxylation activity might be mediated by reversible phosphorylation of Ser55. PMID:24435212

Chao, Qing; Liu, Xiao-Yu; Mei, Ying-Chang; Gao, Zhi-Fang; Chen, Yi-Bo; Qian, Chun-Rong; Hao, Yu-Bo; Wang, Bai-Chen

2014-05-01

242

Temperature and light effects on the circadian rhythm and locomotory activity of the plains garter snake (Thamnophis radix hayendi)  

Microsoft Academic Search

The Locomotory activity of the Plains Garter snake was determined under L\\/D: 12\\/12 conditions at five constant temperatures and three light intensities during the light period. The snakes were diurnal at low temperatures with nocturnal activity increasing in various amounts at higher temperatures. The different light intensities had relatively small effects on the activity rhythm.Activity was recorded under four constant

C. Heckrotte

1975-01-01

243

Integral floating system: new approach of autostereoscopic display  

NASA Astrophysics Data System (ADS)

Integral floating system is recent development of autostereoscopic display. It consists of the integral imaging system and the floating device as depicted in the name. The integrated image forms a floating 3D image in the vicinity of the observer through the floating device which can be either a convex lens or a concave mirror. The integral floating system can provide dynamic 3D images with great feel of depth. This paper reviews the main concepts and the special characteristics of the integral floating system. Moreover, some improvements and analysis will be presented with some basic experimental results.

Min, Sung-Wook

2009-11-01

244

Development and Progress in Enabling the Photocatalyst Ti02 Visible-Light-Active  

NASA Technical Reports Server (NTRS)

Photocatalytic oxidation (PCO) of organic contaminants is a promising air and water quality management approach which offers energy and cost savings compared to thermal catalytic oxidation (TCO). The most widely used photocatalyst, anatase TiO2, has a wide band gap (3.2 eV) and is activated by UV photons. Since solar radiation consists of less than 4% UV, but contains 45% visible light, catalysts capable of utilizing these visible photons need to be developed to make peo approaches more efficient, economical, and safe. Researchers have attempted various approaches to enable TiO2 to be visible-light-active with varied degrees of success'. Strategies attempted thus far fall into three categories based on their electrochemical' mechanisms: 1) narrowing the band gap of TiO2 by implantation of transition metal elements or nonmetal elements such as N, S, and C, 2) modifying electron-transfer processes during PCO by adsorbing sensitizing dyes, and 3) employing light-induced interfacial electron transfer in the heteronanojunction systems consisting of narrow band gap semiconductors represented by metal sulfides and TiO2. There are diverse technical approaches to implement each of these strategies. This paper presents a review of these approaches and results of the photocatalytic activity and photonic efficiency of the end .products under visible light. Although resulting visible-light-active (VLA) photocatalysts show promise, there is often no comparison with unmodified TiO2 under UV. In a limited number of studies where such comparison was provided, the UV-induced catalytic activity of bare TiO2 is much greater than the visible-light-induced catalytic activity of the VLA catalyst. Furthermore, VLA-catalysts have much lower quantum efficiency compared to the approx.50% quantum efficiency of UV-catalysts. This stresses the need for continuing research in this area.

Levine, Lanfang H.; Coutts, Janelle L.; Clausen, Christian A.

2011-01-01

245

The Effect of Multiple Sequential Light Sources to Activate Aminolevulinic Acid in the Treatment of Actinic Keratoses: A Retrospective Study  

PubMed Central

There is a lack of research regarding the sequential use of multiple light sources for topical 5-aminolevulinic acid activation in photodynamic therapy for actinic keratosis. This study evaluated 5-aminolevulinic acid-photodynamic therapy for actinic keratosis using blue light combined with red light, pulsed dye laser, and/or intense pulsed light in a retrospective fashion. Field-directed 5-aminolevulinic acid-photodynamic therapy was performed with blue light only, blue light + pulsed dye laser, blue light + intense pulsed light, blue light + pulsed dye laser + intense pulsed light, or blue light + red light + pulsed dye laser + intense pulsed light for nonhyperkeratotic actinic keratoses of face, scalp, or upper trunk. Blue light + intense pulsed light + pulsed dye laser produced greater patient-reported improvement in actinic keratoses than blue light or blue light + intense pulsed light and greater subject-reported improvement in overall skin quality than blue light + intense pulsed light. The addition of red light led to no further benefit in either outcome measure. Photodynamic therapy with multiple, sequential laser and light sources led to greater patient-graded improvement in actinic keratoses than that with a single light source (blue light), without significant differences in post-treatment adverse events. However, the small, widely disparate number of patients between groups and follow-up times between patients, as well as retrospective assessments based on subjective patient recall, severely limit the significance of these findings. Nevertheless, the results raise interesting questions regarding the use of multiple light and laser sources for photodynamic therapy of actinic keratoses and warrant further research with a prospective, randomized, controlled study. PMID:25276272

Goldman, Mitchel P.; Fabi, Sabrina G.; Guiha, Isabella

2014-01-01

246

Slow and fast light in metal/dielectric composites with passive and active host matrices  

NASA Astrophysics Data System (ADS)

The optical properties of metal/dielectric composites (metal with dielectric core and pure metal inclusions) in passive and active host matrices are studied. It is shown that the real and imaginary parts of the refractive index of the composites with metal covered inclusions have two maxima at two resonant frequencies. Both types of composites show strong anomalous dispersion of the real part of refractive index. The active host matrices can considerably reduce the absorption and provide the conditions for the propagation of weakly damping light waves at the resonant frequencies. The weakly spreading wave packets of light with negative group velocity can be experimentally observed in these composites.

Mal'nev, V. N.; Shewamare, Sisay

2013-10-01

247

NSLS 2007 Activity Report (National Synchrotron Light Source Activity Report 2007)  

SciTech Connect

The National Synchrotron Light Source is one of the world's most productive and cost-effective user facilities. With 2,219 individual users, about 100 more than last year, and a record-high 985 publications, 2007 was no exception. In addition to producing an impressive array of science highlights, which are included in this Activity Report, many NSLS users were honored this year for their scientific accomplishments. Throughout the year, there were major strides in the development of the scientific programs by strengthening strategic partnerships with major research resources and with the Center for Functional Nanomaterials (CFN). Of particular note, the Consortium for Materials Properties Research in Earth Sciences (COMPRES) received renewed funding for the next five years through the National Science Foundation. COMPRES operates four high-pressure NSLS beamlines--X17B2, X17B3, X17C, and U2A--and serves the earth science community as well as the rapidly expanding segment of researchers using high-pressure techniques in materials, chemical, and energy-related sciences. A joint appointment was made between the NSLS and Stony Brook University to further enhance interactions with COMPRES. There was major progress on two key beamline projects outlined in the Five-Year Strategic Plan: the X25 beamline upgrade and the construction of the X9 small angle scattering (SAXS) beamline. The X25 overhaul, which began with the installation of the in-vacuum mini-gap undulator (MGU) in January 2006, is now complete. X25 is once again the brightest beamline for macromolecular crystallography at the NSLS, and in tandem with the X29 undulator beamline, it will keep the NSLS at the cutting edge in this important area of research. Upgrade work associated with the new MGU and the front end for the X9 SAXS beamline--jointly developed by the NSLS and the CFN--also was completed. Beamline X9 will host the SAXS program that currently exists at beamline X21 and will provide new microbeam SAXS capabilities and much-needed beam time for the life sciences, soft condensed matter physics, and nanoscience communities. Looking toward the future, a significant step has been made in expanding the user base and diversifying the work force by holding the first Historically Black Colleges and Universities (HBCU) Professors' Workshop. The workshop, which brought 11 professors to the NSLS to learn how to become successful synchrotron users, concluded with the formation of an HBCU User Consortium. Finally, significant contributions were made in optics and detector development to enhance the utilization of the NSLS and address the challenges of NSLS-II. In particular, x-ray detectors developed by the NSLS Detector Section have been adopted by an increasing number of research programs both at the NSLS and at light sources around the world, speeding up measurement times by orders of magnitude and making completely new experiments feasible. Significant advances in focusing and high-energy resolution optics have also been made this year.

Miller ,L.; Nasta, K.

2008-05-01

248

Floating zone melting of cadmium telluride  

NASA Technical Reports Server (NTRS)

To produce superior crystals of cadmium telluride, floating zone melting in space has been proposed. Techniques required for floating zone melting of cadmium telluride are being developed. We have successfully float-zoned cadmium telluride on earth using square rods. A resistance heater was constructed for forming the molten zone. Evaporation of the molten zone was controlled by adding excess cadmium to the growth ampoule combined with heating of the entire ampoule. An effective method to hold the feed rod was developed. Slow rotation of the growth ampoule was proven experimentally to be necessary to achieve a complete symmetric molten zone. Most of the resultant cylindrical rods were single crystals with twins. Still needed is a suitable automatic method to control the zone length. We tried a fiber optical technique to control the zone length, but experiments showed that application of this technique to automate zone length control is unlikely to be successful.

Chang, Wen-Ming; Regel, L. L.; Wilcox, W. R.

1992-01-01

249

Near-infrared light controlled photocatalytic activity of carbon quantum dots for highly selective oxidation reaction  

NASA Astrophysics Data System (ADS)

Selective oxidation of alcohols is a fundamental and significant transformation for the large-scale production of fine chemicals, UV and visible light driven photocatalytic systems for alcohol oxidation have been developed, however, the long wavelength near infrared (NIR) and infrared (IR) light have not yet fully utilized by the present photocatalytic systems. Herein, we reported carbon quantum dots (CQDs) can function as an effective near infrared (NIR) light driven photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde. Based on the NIR light driven photo-induced electron transfer property and its photocatalytic activity for H2O2 decomposition, this metal-free catalyst could realize the transformation from benzyl alcohol to benzaldehyde with high selectivity (100%) and conversion (92%) under NIR light irradiation. HO&z.rad; is the main active oxygen specie in benzyl alcohol selective oxidative reaction confirmed by terephthalic acid photoluminescence probing assay (TA-PL), selecting toluene as the substrate. Such metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes with high conversion, demonstrating a potential application of accessing traditional alcohol oxidation chemistry.Selective oxidation of alcohols is a fundamental and significant transformation for the large-scale production of fine chemicals, UV and visible light driven photocatalytic systems for alcohol oxidation have been developed, however, the long wavelength near infrared (NIR) and infrared (IR) light have not yet fully utilized by the present photocatalytic systems. Herein, we reported carbon quantum dots (CQDs) can function as an effective near infrared (NIR) light driven photocatalyst for the selective oxidation of benzyl alcohol to benzaldehyde. Based on the NIR light driven photo-induced electron transfer property and its photocatalytic activity for H2O2 decomposition, this metal-free catalyst could realize the transformation from benzyl alcohol to benzaldehyde with high selectivity (100%) and conversion (92%) under NIR light irradiation. HO&z.rad; is the main active oxygen specie in benzyl alcohol selective oxidative reaction confirmed by terephthalic acid photoluminescence probing assay (TA-PL), selecting toluene as the substrate. Such metal-free photocatalytic system also selectively converts other alcohol substrates to their corresponding aldehydes with high conversion, demonstrating a potential application of accessing traditional alcohol oxidation chemistry. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr00092c

Li, Haitao; Liu, Ruihua; Lian, Suoyuan; Liu, Yang; Huang, Hui; Kang, Zhenhui

2013-03-01

250

Optical imaging of fast light-evoked fast neural activation in amphibian retina  

NASA Astrophysics Data System (ADS)

High performance functional imaging is needed for dynamic measurements of neural processing in retina. Emerging techniques of visual prosthesis also require advanced methodology for reliable validation of electromagnetic stimulation of the retina. Imaging of fast intrinsic optical responses associated with neural activation promises a variety of technical advantages over traditional single and multi-channel electrophysiological techniques for these purposes, but the application of fast optical signals for neural imaging has been limited by low signal to noise ratio and high background light intensity. However, using optimized near infrared probe light and improved optical systems, we have improved the optical signals substantially, allowing single pass measurements. Fast photodiode measurements typically disclose dynamic transmitted light changes of whole retina at the level of 10 -4 dI/I, where dI is the dynamic optical change and I is the baseline light intensity. Using a fast high performance CCD, we imaged fast intrinsic optical responses from isolated retina activated by a visible light flash. Fast, high resolution imaging disclosed larger local optical responses, and showed evidence of multiple response components with both negative- and positive-going signals, on different timescales. Darkfield imaging techniques further enhanced the sensitivity of optical measurements. At single cell resolution, brightfield imaging disclosed maxima of optical responses ~5% dI/I, while darkfield imaging showed maxima of optical responses exceeding 10% dI/I. In comparison with simultaneous electrophysiological recording, optical imaging provided much better localized patterns of response over the activated area of the retina.

Yao, Xin-Cheng; George, John S.

2006-02-01

251

Well casing float shoe or collar  

SciTech Connect

A well casing float shoe which is adapted for a variety of well installations consists of a tubular metal shoe member filled with cementitious material having a longitudinal bore surrounding and securing in place a tubular metal sleeve. The metal sleeve is threaded at the top and bottom ends to receive a variety of sizes and types of check valves. A well casing float collar has the same construction, but the tubular shoe member is replaced with a tubular metal collar with threaded connections both above and below the cementitious filler material.

Kaufman, H. J.

1985-08-06

252

Visible Light Controlled Release of Anticancer Drug through Double Activation of Prodrug  

PubMed Central

We designed and synthesized a novel double activatable prodrug system (drug–linker–deactivated photosensitizer), containing a photocleavable aminoacrylate-linker and a deactivated photosensitizer, to achieve the spatiotemporally controlled release of parent drugs using visible light. Three prodrugs of CA-4, SN-38, and coumarin were prepared to demonstrate the activation of deactivated photosensitizer by cellular esterase and the release of parent drugs by visible light (540 nm) via photounclick chemistry. Among these prodrugs, nontoxic coumarin prodrug was used to quantify the release of parent drug in live cells. About 99% coumarin was released from the coumarin prodrug after 24 h of incubation with MCF-7 cells followed by irradiation with low intensity visible light (8 mW/cm2) for 30 min. Less toxic prodrugs of CA-4 and SN-38 killed cancer cells as effectively as free drugs after the double activation. PMID:24900573

2012-01-01

253

Treatment of actinic cheilitis by photodynamic therapy with 5-aminolevulinic acid and blue light activation.  

PubMed

Actinic cheilitis (AC), a common disorder of the lower lip, should be treated early to prevent progression to invasive squamous cell carcinoma. This study evaluated the safety and efficacy of photodynamic therapy (PDT) with 5-aminolevulinic acid (ALA) activated by blue light for the treatment of AC. Fifteen patients with clinically evident or biopsy-proven AC received two treatments with ALA PDT with blue light activation. Treatments were spaced three to five weeks apart. Most patients achieved 65% to 75% clearance three to five weeks after the first treatment and all achieved more than 75% clearance one month after the second treatment. Three patients achieved complete clearance. Pain and burning during irradiation were absent or mild. All patients said they would repeat the procedure. ALA PDT with 417 nm blue light is a promising option for the treatment of AC of the lower lip. PMID:22052302

Zaiac, Martin; Clement, Annabelle

2011-11-01

254

Fast optical recording of light-flash evoked neural activation in amphibian retina  

NASA Astrophysics Data System (ADS)

Imaging of fast intrinsic optical responses closely associated with neural activation promises important technical advantages over traditional single and multi-channel electrophysiological techniques for dynamic measurements of visual processing and early detection of eye diseases. We have developed a fast, no-moving-parts optical coherence tomography (OCT), system based on an electro-optic phase modulator, and used it to record dynamic near infrared (NIR) light scattering changes in frog retina activated by a visible light-flash. We also employed transmitted light for highly sensitive measurement and imaging of neural activation, and to optimize illumination and optical configuration. Using a photodiode detector, we routinely measured dynamic NIR transmitted optical responses in single passes. When the whole retina was illuminated by a visible light-flash, a positive peak was typically observed in transmitted light measurements. CCD image sequences disclosed larger fractional responses, in some cases exceeding 0.5% in individual pixels, and showed evidence of multiple response components with both negative- and positive-going signals with different timescales and complex but consistent spatial organization. The fast negative-going signals are highly correlated with the a-wave of the electrophysiological signals, and may reflect the activation of photoreceptors. The fast positive-going responses are related to the b-wave of the electrophysiological signals, and may result from the activation of ON bipolar cells. Slow optical responses may signal metabolic changes of retinal tissue. Our experimental results and theoretical analysis suggest that the optical responses may result from dynamic volume changes associated with neural activation, corresponding to ion and water flow across the cell membrane.

Yao, Xin-Cheng; George, John S.

2005-08-01

255

Improvements in floating point addition/subtraction operations  

DOEpatents

Apparatus is described for decreasing the latency time associated with floating point addition and subtraction in a computer, using a novel bifurcated, pre-normalization/post-normalization approach that distinguishes between differences of floating point exponents.

Farmwald, P.M.

1984-02-24

256

14 CFR 29.751 - Main float buoyancy.  

...necessary to support the maximum weight of the rotorcraft in fresh water must be exceeded by— (1) 50 percent, for single...multiple floats. (b) Each main float must have enough water-tight compartments so that, with any single...

2014-01-01

257

14 CFR 27.751 - Main float buoyancy.  

...necessary to support the maximum weight of the rotorcraft in fresh water must be exceeded by— (1) 50 percent, for single...multiple floats. (b) Each main float must have enough water-tight compartments so that, with any single...

2014-01-01

258

The Thermodynamic and Cost Benefits of Floating Cooling Systems  

E-print Network

. The application of a floating cooling concept to evaporative heat rejection systems can have significant impact on improving plant performance. The floating cooling concept refers to the optimization of yearly plant output and energy consumption by taking...

Svoboda, K. J.; Klooster, H. J.; Johnnie, D. H., Jr.

1983-01-01

259

14 CFR 136.11 - Helicopter floats for over water.  

Code of Federal Regulations, 2011 CFR

14 Aeronautics and Space 3 2011-01-01 2011-01-01... Helicopter floats for over water. 136.11 Section 136.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Helicopter floats for over water. (a) A helicopter...

2011-01-01

260

14 CFR 136.11 - Helicopter floats for over water.  

Code of Federal Regulations, 2012 CFR

14 Aeronautics and Space 3 2012-01-01 2012-01-01... Helicopter floats for over water. 136.11 Section 136.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Helicopter floats for over water. (a) A helicopter...

2012-01-01

261

14 CFR 136.11 - Helicopter floats for over water.  

14 Aeronautics and Space 3 2014-01-01 2014-01-01... Helicopter floats for over water. 136.11 Section 136.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Helicopter floats for over water. (a) A helicopter...

2014-01-01

262

14 CFR 136.11 - Helicopter floats for over water.  

Code of Federal Regulations, 2013 CFR

14 Aeronautics and Space 3 2013-01-01 2013-01-01... Helicopter floats for over water. 136.11 Section 136.11 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Helicopter floats for over water. (a) A helicopter...

2013-01-01

263

The syntactic and semantic roots of floating quantification  

E-print Network

Through the study of floating quantifiers in a variety of languages, I demonstrate that floating quantification is not a uniform phenomenon and outline a series of puzzles that force us to adopt a two-part analysis. I argue ...

Fitzpatrick, Justin Michael

2006-01-01

264

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2010 CFR

...shall completely cover the annular space between the external floating roof and the wall of the storage vessel in a continuous fashion. (c) EFR inspection requirements. To demonstrate compliance for an external floating roof vessel, the owner or...

2010-07-01

265

Dawn – dusk simulation light therapy of disturbed circadian rest –activity cycles in demented elderly  

Microsoft Academic Search

Abstract We investigated whether low intensity dawn – dusk simulation (DDS), a ‘naturalistic’ form of light therapy designed to embed sleep in its accustomed phase, could improve the disturbed circadian rest – activity cycle, nocturnal sleep and and\\/or cognitive functions in dementia. A protocol of 3 weeks each of baseline, treatment and follow-up was completed by 13 patients (85 yr

Paola Fontana Gasio; Kurt Kra Uchi; Christian Cajochen; Eus Van Someren; Isabelle Amrhein; Mona Pache; Egemen Savaskan; Anna Wirz-justice

266

however, use chemical gradients, light or other stimuli to passively or actively control  

E-print Network

however, use chemical gradients, light or other stimuli to passively or actively control the motion, perhaps serving as a biochemical sensor or navigation control- ler. Such systems are, however, limited by the often stochastic nature of cellular motion, and bytherelativelybrieflifetimesofcells(depend- ing

267

PI Department Title Amount Sayed Sadeghi Physics Light-activated Nanoparticle Molecules  

E-print Network

Music A Request for Funds to Participate in the Conducting Master Class at the Oregon Bach FestivalPI Department Title Amount Funded Sayed Sadeghi Physics Light-activated Nanoparticle Molecules $10,138 Kelly Gamble ACC/FIN Does Intuition Influence Investor Judgment? $9,856 Derrick W. Smith Education

Alabama in Huntsville, University of

268

WEED MANAGEMENT IN ROUNDUP READY COTTON USING A LIGHT-ACTIVATED SPRAYER. D. Alan Peters  

E-print Network

WEED MANAGEMENT IN ROUNDUP READY COTTON USING A LIGHT-ACTIVATED SPRAYER. D. Alan Peters Texas Tech in a Roundup Ready cotton production system using mechanical cultivation, a conventional hooded sprayer; Treflan PPI followed by a postemergence over-the-top (POT) broadcast application of Roundup Ultra at 1 qt

Mukhtar, Saqib

269

A new pixel circuit for active matrix organic light emitting diodes  

Microsoft Academic Search

We propose a new thin-film-transistor (TFT) pixel circuit for active-matrix organic light-emitting diode (AMOLED) composed of four TFTs and two capacitors. The simulation results, based on the device performances measured for an OLED and a poly-Si TFT, indicate that the proposed circuit has high immunity to the variation of poly-Si TFT characteristics

Joon-Chul Goh; Hoon-Ju Chung; Jin Jang; Chul-Hi Han

2002-01-01

270

A Polysilicon Active Matrix Organic Light Emitting Diode Display with Integrated Drivers  

Microsoft Academic Search

The design of an active matrix organic light emitting diode (AMOLED) display using a polysilicon thin film transistor pixel is described. Characteristics of the OLED response in the low current regime are described and their impact on the design of integrated driver circuitry is discussed. Integrated data and select scanners which generate the signals necessary for data capture and pixel

R. M. A. Dawson; Z. Shen; D. A. Furst; S. Connor; J. Hsu; M. G. Kane; R. G. Stewart; A. Ipri; C. N. King; P. J. Green; R. T. Flegal; S. Pearson; W. A. Barrow; E. Dickey; K. Ping; S. Robinson; C. W. Tang; S. Van Slyke; C. H. Chen; J. Shi; M. H. Lu; M. Moskewicz; J. C. Sturm

1999-01-01

271

1994 Activity Report, National Synchrotron Light Source. Annual report, October 1, 1993-September 30, 1994  

SciTech Connect

This report is a summary of activities carried out at the National Synchrotron Light Source during 1994. It consists of sections which summarize the work carried out in differing scientific disciplines, meetings and workshops, operations experience of the facility, projects undertaken for upgrades, administrative reports, and collections of abstracts and publications generated from work done at the facility.

Rothman, E.Z. [ed.

1995-05-01

272

An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching  

Microsoft Academic Search

This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated by three different light sources. The samples were randomly divided into 3 groups ( n = 15), according to the catalyst

W. Kabbach; D. M. Zezell; M. C. Bandéca; T. M. Pereira; M. F. Andrade

2010-01-01

273

The Examination of the Educational Effects of Some Writing Activities in the Light of Student Opinions  

ERIC Educational Resources Information Center

The aim of this research is to discover and compare the effects of writing prompt and expository writing from an educational perspective in the light of student opinions. The study was conducted according to qualitative research approach and content analysis was conducted. Two activities which were prepared with respect to objectives of writing…

Ozturan Sagirli, Meryem

2010-01-01

274

Synthesis of indoles using visible light: photoredox catalysis for palladium-catalyzed c?h activation.  

PubMed

A combined palladium- and photoredox-catalyzed C?H olefination enables the synthesis of indoles. By using visible light, the direct C?H activation of aromatic enamines can be achieved and a variety of indole derivatives can be obtained in good yields under mild reaction conditions. PMID:25284332

Zoller, Jochen; Fabry, David C; Ronge, Meria A; Rueping, Magnus

2014-11-24

275

Vanadium pentoxide modified polycrystalline silicon anode for active-matrix organic light-emitting diodes  

E-print Network

to be an efficient anode for organic light-emitting diode OLED X. L. Zhu, J. X. Sun, H. J. Peng, Z. G. Meng, M. Wong an ultrathin vanadium pentoxide V2O5 layer on the p-Si anode, the performance of the OLED can be greatly with the active p-Si layer of thin-film transistors in active-matrix OLED displays. © 2005 American Institute

276

Seasonal changes in sheltering: effect of light and temperature on diel activity in juvenile salmon  

Microsoft Academic Search

Previous work has shown that juvenile Atlantic salmon,Salmo salarL, are predominantly nocturnal during winter (spending the day sheltering in streambed refuges) but become active 24h a day in the summer. Observations of salmon in a semi-natural stream revealed how light, temperature and time of year determined these activity patterns; we also tested whether the life-history strategy of the fish affected

SVEINN K VALDIMARSSON; NEIL B METCALFE; JOHN E THORPE; FELICITY A HUNTINGFORD

1997-01-01

277

Free-floating planets from microlensing  

NASA Astrophysics Data System (ADS)

Gravitational microlensing has an unique sensitivity to exoplanets at outside of the snow-line and even exoplanets unbound to any host stars because the technique does not rely on any light from the host but the gravity of the lens. MOA and OGLE collaborations reported the discovery of a population of unbound or distant Jupiter-mass objects, which are almost twice (1.8_{-0.8}^{+1.7}) as common as main-sequence stars, based on two years of gravitational microlensing survey observations toward the Galactic Bulge. These planetary-mass objects have no host stars that can be detected within about ten astronomical units by gravitational microlensing. However a comparison with constraints from direct imaging suggests that most of these planetary-mass objects are not bound to any host star. The such short-timescale unbound planetary candidates have been detected with the similar rate in on-going observations and these groups are working to update the analysis with larger statistics. Recently, there are also discoveries of free-floating planetary mass objects by the direct imaging in young star-forming regions and in the moving groups, but these objects are limited to massive objects of 3 to 15 Jupiter masses.They are more massive than the population found by microlensing. So they may be a different population with the different formation process, either similar with that of stars and brown dwarfs, or formed in proto-planetary disks and subsequently scattered into unbound or very distant orbits. It is important to fill the gap of these mass ranges to fully understand these populations. The Wide Field Infrared Survey Telescope (WFIRST) is the highest ranked recommendation for a large space mission in the recent New Worlds, New Horizons (NWNH) in Astronomy and Astrophysics 2010 Decadal Survey. Exoplanet microlensing program is one of the primary science of WFIRST. WFIRST will find about 3000 bound planets and 2000 unbound planets by the high precision continuous survey 15 min. cadence. WFIRST can complete the statistical census of planetary systems in the Galaxy, from super-Earths beyond the snow-line to gravitationally unbound planets - a discovery space inaccessible to other exoplanet detection techniques.

Sumi, Takahiro

2014-06-01

278

Optimization of Automated Float Glass Lines Byungsoo Na, Shabbir Ahmed  

E-print Network

Optimization of Automated Float Glass Lines Byungsoo Na, Shabbir Ahmed , George Nemhauser and Joel of Scope and Purpose Flat glass is approximately a $20 billion/year industry worldwide, with almost all flat glass products being manufactured on float glass lines. New technologies are allowing float glass

Ahmed, Shabbir

279

Insertion loss prediction of floating floors used in ship cabins  

Microsoft Academic Search

In this paper, vibration reduction in ship cabins by using floating floor is studied. Two theoretical models are developed and predicted insertion losses of floating floors are compared to experimental results, where measurements are done in the mock-up built for simulating typical ship cabins. The floating floor consists of upper board and mineral wool, which is in turn laid on

Sun-Il Cha; Ho-Hwan Chun

2008-01-01

280

A simulation of Argo float distribution in the Southern Ocean  

Microsoft Academic Search

Spatial distribution of the Argo floats in the Southern Ocean was simulated based on an output of a high resolution ocean general circulation model. Giving initial uniform distribution of the floats, numerical simulations were performed for the parking depths of 2000 m and 1000 m, respectively, with and without sea ice. When the sea ice was ignored, the floats were

Tsugukazu Okumura; Naoto Iwasaka

2005-01-01

281

Light-Triggered Modulation of Cellular Electrical Activity by Ruthenium Diimine Nanoswitches  

PubMed Central

Ruthenium diimine complexes have previously been used to facilitate light-activated electron transfer in the study of redox metalloproteins. Excitation at 488 nm leads to a photoexcited state, in which the complex can either accept or donate an electron, respectively, in the presence of a soluble sacrificial reductant or oxidant. Here, we describe a novel application of these complexes in mediating light-induced changes in cellular electrical activity. We demonstrate that RubpyC17 ([Ru(bpy)2(bpy-C17)]2+, where bpy is 2,2?-bipyridine and bpy-C17 is 2,2?-4-heptadecyl-4?-methyl-bipyridine), readily incorporates into the plasma membrane of cells, as evidenced by membrane-confined luminescence. Excitable cells incubated in RubpyC17 and then illuminated at 488 nm in the presence of the reductant ascorbate undergo membrane depolarization leading to firing of action potentials. In contrast, the same experiment performed with the oxidant ferricyanide, instead of ascorbate, leads to hyperpolarization. These experiments suggest that illumination of membrane-associated RubpyC17 in the presence of ascorbate alters the cell membrane potential by increasing the negative charge on the outer face of the cell membrane capacitor, effectively depolarizing the cell membrane. We rule out two alternative explanations for light-induced membrane potential changes, using patch clamp experiments: (1) light-induced direct interaction of RubpyC17 with ion channels and (2) light-induced membrane perforation. We show that incorporation of RubpyC17 into the plasma membrane of neuroendocrine cells enables light-induced secretion as monitored by amperometry. While the present work is focused on ruthenium diimine complexes, the findings point more generally to broader application of other transition metal complexes to mediate light-induced biological changes. PMID:23419103

2013-01-01

282

NSLS 2005 ACTIVITY REPORT (NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 2005).  

SciTech Connect

In 2005, the NSLS proved itself, once again, to be a center of scientific excellence. This remarkable facility, commissioned in the early 1980s, is still attracting some of the world's best researchers in almost every scientific field, who produce more than seven hundred scientific papers every year using the NSLS. The 'Science Highlights' and 'Feature Highlights' sections of this report are just a small sampling of the many, many impressive research projects conducted at the NSLS in 2005. For example, a user group synthesized and studied zinc-oxide nanowires, which have applications in many optical and electrical devices. Another user group studied how strontium and uranium are removed from high-level radioactive waste. And in another interesting study, users deciphered the basis for antibiotic resistance. However, as always, the success of these projects depends on the performance of the facility. Again this year, the rings were in top form--reliability was 96 percent for the x-ray ring and 99 percent for the VUV-IR ring. Additionally, to keep the NSLS as productive as possible and to continue to attract users, many beamline upgrade projects were completed this year. One of the highlights of these upgrades is the new mini-gap undulator installed at beamline X25. This insertion device is providing a much brighter x-ray source for the program at X25. In the always important area of safety, several noteworthy activities took place this year. In particular, NSLS staff made a major commitment to labeling and inspecting electrical equipment. And perhaps the best news is what didn't happen--there were no reportable occurrences related to environmental, safety, or health issues in 2005, and no injuries that resulted in restricted or lost time. We all owe thanks to the dedicated NSLS staff and users who have ensured that the NSLS remains a reliable, safe, up-to-date research facility. As 2005 came to an end, I stepped down as NSLS Chairman in order to focus my primary efforts on NSLS-II, the world-leading third-generation synchrotron planned for construction at BNL. NSLS-II passed a critical milestone in 2005 with the approval by the Department of Energy of CD-0. BNL has established the NSLS-II Project Organization within the Light Sources Directorate to put in place the management systems and infrastructure necessary to execute this complex undertaking. I will serve as NSLS-II Project Director and also retain my position as Associate Laboratory Director for Light Sources, with the NSLS reporting to me. Another exciting development is the planned establishment of the Joint Photon Sciences Institute (JPSI). JPSI will be devoted to cultivating and fostering collaborative, interdisciplinary R&D in areas of the physical sciences, engineering, and the life sciences that are united in employing synchrotron-based methods. JPSI will also develop new methods and applications that exploit the unique capabilities of NSLS-II and will serve as a gateway for NSLS-II users. JPSI will be a partnership between the Department of Energy and New York State, and I am delighted that New York State Governor George Pataki has pledged $30 million for the construction of the JPSI building. The building will be located adjacent to NSLS-II and will contain offices, meeting rooms, and specialized laboratories. The operating expenses of JPSI and funding for its research programs will be provided by the federal government. Until a permanent NSLS Director is selected, NSLS User Science Division Associate Chair Chi-Chang Kao will serve as the Interim NSLS Director. I couldn't be leaving the facility in more capable hands. Chi-Chang will lead NSLS staff and users this year in the development of a five-year strategic plan for the NSLS, scheduled for completion by the end of summer 2006. The plan will outline the course for the future operation and development of the NSLS, and will help ensure that the future of the NSLS remains as bright as its past.

MILLER, L. (EDITOR)

2006-05-01

283

Submerged floating tunnels (SFTs) for Norwegian fjords  

Microsoft Academic Search

Submerged floating tunnels (SFTs) weigh roughly the same as the surrounding water. The loads on the tunnel depend on the variation of the forces on the tunnel. The forces come from variation in traffic, current, temperature, waves, weight of water, weight of concrete, growth on the tunnel, wear of asphalt, dust and debris, relaxation of prestress and shrinkage and creep

Per Tveit

2010-01-01

284

Coupled analysis of floating production systems  

Microsoft Academic Search

Fully coupled global analysis of Floating Production Systems, including the vessel, the mooring system and the riser system is described. Design of the system can be a daunting task, involving more than 1000 load cases for global analysis. The primary driver for the mooring system and for the riser system is motion of the vessel. Vessel motions are driven by

D. L. Garrett

2005-01-01

285

Autonomous refresh of floating body cell (FBC)  

Microsoft Academic Search

Physics of autonomous refresh of FBC is presented. Current input to the floating body by impact ionization and output by charge pumping can balance to make FBC refresh by itself without sense amplifier operation. Thanks to this feature, multiple cells on a BL can be refreshed simultaneously, leading to a drastic reduction of BL charging current compared to the conventional

Takashi Ohsawa; Ryo Fukuda; Tomoki Higashi; Katsuyuki Fujita; Fumiyoshi Matsuoka; Tomoaki Shino; Hironobu Furuhashi; Yoshihiro Minami; Hiroomi Nakajima; Takeshi Hamamoto; Yohji Watanabe; Akihiro Nitayama; Tohru Furuyama

2008-01-01

286

A New Concept in Floating Production Systems  

Microsoft Academic Search

This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hull

M. H. Patel; J. I. Montgomery; M. S. Worley

1984-01-01

287

Daphnia (zoomed on floating blood cells)  

NSDL National Science Digital Library

These pin drops are the clearly defined blood cells of the Daphnia. We are only able to see the cells with use of a microscope. Keep in mind that the cells are not confined in any blood vessel (called an open circulatory system) and freely float throughout the body.

Katie Hale (CSUF;Biological Sciences)

2007-07-18

288

[Effect of age, different light conditions, melatonin, and epitalon on lysosomal proteinase activity in the liver and kidneys of rats].  

PubMed

Ageing, melatonin, epithalon (tetrapeptide Ala-Glu-Asp-Gly) and different light conditions effects on protein content and cathepsins B and D activities in rat liver and kidneys lysosomal fractions were studied. Ageing leads to decrease of cathepsins activity in rat liver lysosomal fractions. Constant light and darkness conditions result in earlier age decline of cathepsins activity. Absence of day and night succession in comparison with alternating light conditions causes decline of both general and specific cathepsin D activity. Melatonin and epithalon administration resulted in decrease of cathepsin D activity in liver only under control interchangeable light conditions. Cathepsin B activity in liver and kidneys lysosomal fractions declined in all experimental light conditions. Cathepsins activity decrease under the influence of epiphysial factors is evidently connected with their inhibitory effect on protein and general metabolism. PMID:17152724

Rendakov, N L; Tiutiunnik, N N; Vinogradova, I A

2006-01-01

289

Highly Active TiO2-Based Visible-Light Photocatalyst with Nonmetal Doping and Plasmonic Metal Decoration  

SciTech Connect

A sandwich-structured photocatalyst shows an excellent performance in degradation reactions of a number of organic compounds under UV, visible light, and direct sunlight (see picture). The catalyst was synthesized by a combination of nonmetal doping and plasmonic metal decoration of TiO2 nanocrystals, which improves visible-light activity and enhances light harvesting and charge separation, respectively.

Zhang, Qiao [University of California, Riverside; Lima, Diana Q. [University of California, Riverside; Chi, Miaofang [ORNL; Yin, Yadong [University of California, Riverside

2011-01-01

290

Study on the activation of styrene-based shape memory polymer by medium-infrared laser light  

SciTech Connect

This paper demonstrates the feasibility of shape memory polymer (SMP) activation by medium-infrared laser light. Medium-infrared light is transmitted by an optical fiber embedded in the SMP matrix, and the shape recovery process and temperature distribution are recorded by an infrared camera. Light-induced SMP exhibits potential applications in biomedicines and flexible displays.

Leng Jinsong; Yu Kai; Lan Xin [Center for Composite Materials and Structures, Harbin Institute of Technology, HeiLongJiang 150001 (China); Zhang Dawei [Center for Composite Materials and Structures, Harbin Institute of Technology, HeiLongJiang 150001 (China); Material Science and Engineering College, Northeast Forestry University, HeiLongJiang 150040 (China); Liu Yanju [Department of Astronautical Science and Mechanics, Harbin Institute of Technology, HeiLongJiang 150001 (China)

2010-03-15

291

Photocatalytic activity of Fe-doped CaTiO? under UV-visible light.  

PubMed

The photocatalytic degradation of methylene blue (MB) over Fe-doped CaTiO? under UV-visible light was investigated. The as-prepared samples were characterized using X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with an energy dispersive spectrometer (EDS) system, Fourier transform infrared spectra (FT-IR), and UV-visible diffuse reflectance spectroscopy (DRS). The results show that the doping with Fe significantly promoted the light absorption ability of CaTiO? in the visible light region. The Fe-doped CaTiO? exhibited higher photocatalytic activity than CaTiO? for the degradation of MB. However, the photocatalytic activity of the Fe-doped CaTiO? was greatly influenced by the calcination temperature during the preparation process. The Fe-doped CaTiO? prepared at 500°C exhibited the best photocatalytic activity, with degradation of almost 100% MB (10ppm) under UV-visible light for 180 min. PMID:25079998

Yang, He; Han, Chong; Xue, Xiangxin

2014-07-01

292

Light-inducible spatiotemporal control of gene activation by customizable zinc finger transcription factors.  

PubMed

Advanced gene regulatory systems are necessary for scientific research, synthetic biology, and gene-based medicine. An ideal system would allow facile spatiotemporal manipulation of gene expression within a cell population that is tunable, reversible, repeatable, and can be targeted to diverse DNA sequences. To meet these criteria, a gene regulation system was engineered that combines light-sensitive proteins and programmable zinc finger transcription factors. This system, light-inducible transcription using engineered zinc finger proteins (LITEZ), uses two light-inducible dimerizing proteins from Arabidopsis thaliana, GIGANTEA and the LOV domain of FKF1, to control synthetic zinc finger transcription factor activity in human cells. Activation of gene expression in human cells engineered with LITEZ was reversible and repeatable by modulating the duration of illumination. The level of gene expression could also be controlled by modulating light intensity. Finally, gene expression could be activated in a spatially defined pattern by illuminating the human cell culture through a photomask of arbitrary geometry. LITEZ enables new approaches for precisely regulating gene expression in biotechnology and medicine, as well as studying gene function, cell-cell interactions, and tissue morphogenesis. PMID:22963237

Polstein, Lauren R; Gersbach, Charles A

2012-10-10

293

Characterization of nucleoside triphosphatase activity in isolated pea nuclei and its photoreversible regulation by light  

NASA Technical Reports Server (NTRS)

A nucleoside triphosphatase (NTPase) present in highly purified preparations of pea nuclei was partially characterized. The activity of this enzyme was stimulated by divalent cations (Mg2+ = Mn2+ > Ca2+), but was not affected by the monovalent cations, Na+ and K+. The Mg(2+)-dependent activity was further stimulated by concentrations of Ca2+ in the low micromolar range. It could catalyze the hydrolysis of ATP, GTP, UTP, and CTP, all with a pH optimum of 7.5. The nuclear NTPase activity was not inhibited by vanadate, oligomycin, or nitrate, but was inhibited by relatively low concentrations of quercetin and the calmodulin inhibitor, compound 48/80. The NTPase was stimulated more than 50% by red light, and this effect was reversed by subsequent irradiation with far-red light. The photoreversibility of the stimulation indicated that the photoreceptor for this response was phytochrome, an important regulator of photomorphogenesis and gene expression in plants.

Chen, Y. R.; Roux, S. J.

1986-01-01

294

Light is an active contributor to the vital effects of coral skeleton proxies  

NASA Astrophysics Data System (ADS)

Symbiotic colonies of the coral Acropora sp. were cultured in a factorial design of three temperatures (21, 25 and 28 °C) and two light intensities (200 and 400 ?mol photon m-2 s-1), under constant conditions. A temperature of 25 °C and a light intensity of 200 ?mol photon m-2 s-1 was the starting culture condition. Metabolic (photosynthesis, respiration, calcification and surface expansion rate) and geochemical measurements (?18O, ?13C, Sr/Ca and Mg/Ca) were conducted on 6 colonies for each experimental condition. Metabolic measurements confirmed that respiration, photosynthesis, calcification and surface expansion rate responded to the combined effect of temperature and light. Under each light intensity, mean calcification rate was linearly correlated with mean photosynthetic activity. Geochemical measurements were also influenced by temperature and, to a lesser degree, by light. All geochemical proxies measured on 6 nubbins showed a wide scattering of values, regardless of the environmental condition. Compared to the other proxies, ?18O exhibited a different behavior. It was the only proxy exhibiting temperature tracer behavior. However, while mean values of Sr/Ca, Mg/Ca and ?13C were well correlated, the correlation between the later and mean ?18O differed with light level. This suggests that both skeleton deposition and temperature oxygen fractionation differs according to light intensity. Overall, the effect of light on geochemical values seems to compromise the use of proxy calibrations solely based on temperature influence. Under high light conditions, the great amplitude shown by individual net photosynthesis is directly proportional to the highly variable zooxanthellae density. As light is affecting all of the proxies, we thus assume that the strong geochemical variability observed could be explained by various algae densities, each nubbin responding according to its zooxanthellae amount. Accordingly, we suggest that each symbiosome (the assemblage of few corallites with their symbionts) presents its own vital effect influence over time. Therefore, at a bulk sample scale, light could be considered as one of the major causes of what is commonly referred to as the ‘vital effect’. The meaning of ?18O calibration versus temperature established from distinct colonies differs from calibration calculated from samples collected following the growth axis of a single coral head. Finally, in order to quantitatively reconstruct climatic condition, we suggest a new paradigm based on the statistical treatment of the combination of time-series information from several proxies, all measured on the same sample from a continuous symbiosome.

Juillet-Leclerc, Anne; Reynaud, Stéphanie; Dissard, Delphine; Tisserand, Guillaume; Ferrier-Pagès, Christine

2014-09-01

295

Influence of softening test and light-activation protocols on resin composite polymer structure  

PubMed Central

Objective: This study analyzed the influences of the light-activation protocol and softening test on the degree of conversion (DC) and Knoop Hardness (KHN) of a microhybrid resin composite. Materials and Methods: Filtek Z250 (3M ESPE) was light-activated with a third-generation light-emitting diode (Valo Ultradent) by three protocols – standard, high power, and plasma emulation – or with a quartz-tungsten halogen XL 3000 (3M ESPE) in conventional mode. All modes were set to deliver 19 J/cm2. The DC (N = 20) was determined by Fourier transform infrared spectrometry on the top (T) and bottom (B) surfaces. For the KHN test, samples were subdivided in four groups (n = 5 each) according to the storage media: absolute ethanol, 75% ethanol, distilled water, and air (control group). The KHN values were evaluated on T and B before and 24 h after immersion in the storage media. Data were analyzed by split-plot analysis of variance (ANOVA; for DC) or repeated-measures split-plot ANOVA (for KHN), followed by Tukey's test (? = 0.05). Results: For the DC, the light-activation protocol did not influence the results and there was no difference between T and B. For the KHN test, the light-activation protocol did not influence the results and T showed higher microhardness values than B for all experimental conditions. There were significant differences in KHN depending on the storage media. Samples immersed in absolute ethanol generally presented lower KHN values, with no differences compared to samples in 75% ethanol. Conclusion: The storage media affected the outcomes of the softening test. PMID:24966740

Giorgi, Maria Cecilia Caldas; Lima, Debora Alves Nunes Leite; Marchi, Giselle Maria; Ambrosano, Glaucia Maria; Aguiar, Flavio Henrique Baggio

2014-01-01

296

Overexpression of inactive arylsulphatase mutants and in vitro activation by light-dependent oxidation with vanadate  

PubMed Central

Arylsulphatases B (ASB) and A (ASA) are subject to a unique post-translational modification that is required for their function. The modification reaction, conversion of an active-site cysteine into a formylglycine, becomes saturated when these enzymes are overexpressed. We have removed the possibility of in vivo modification by expressing mutants of ASB and ASA in which the active-site cysteine is substituted with a serine. These mutants are expressed much more efficiently when compared with the native enzymes under identical conditions. The purified ASB mutant can then be converted into catalytically active ASB in vitro using vanadate and light. PMID:15175008

2004-01-01

297

Development of White-Light Emitting Active Layers in Nitride Based Heterostructures for Phosphorless Solid State Lighting  

SciTech Connect

This report provides a summary of research activities carried out at the University of California, San Diego and Central Research of OSRAM SYLVANIA in Beverly, MA partially supported by a research contract from US Department of Energy, DE-FC26-04NT422274. The main objective of this project was to develop III-V nitrides activated by rare earth ions, RE{sup 3+}, which could eliminate the need for phosphors in nitride-based solid state light sources. The main idea was to convert electron-hole pairs injected into the active layer in a LED die to white light directly through transitions within the energy levels of the 4f{sup n}-manifold of RE{sup 3+}. We focused on the following materials: Eu{sup 3+}(red), Tb{sup 3+}(green), Er{sup 3+}(green), Dy{sup 3+}(yellow) and Tm{sup 3+}(blue) in AlN, GaN and alloys of AlN and GaN. Our strategy was to explore candidate materials in powder form first, and then study their behavior in thin films. Thin films of these materials were to be deposited on sapphire substrates using pulsed laser deposition (PLD) and metal organic vapor phase epitaxy (MOVPE). The photo- and cathode-luminescence measurements of these materials were used to investigate their suitability for white light generation. The project proceeded along this route with minor modifications needed to produce better materials and to expedite our progress towards the final goal. The project made the following accomplishments: (1) red emission from Eu{sup 3+}, green from Tb{sup 3+}, yellow from Dy{sup 3+} and blue from Tm{sup 3+} in AlN powders; (2) red emission from Eu{sup 3+} and green emission from Tb{sup 3+} in GaN powder; (3) red emission from Eu{sup 3+} in alloys of GaN and AlN; (4) green emission from Tb{sup 3+} in GaN thin films by PLD; (5) red emission from Eu{sup 3+} and Tb{sup 3+} in GaN thin films deposited by MOVPE; (6) energy transfer from host to RE{sup 3+}; (7) energy transfer from Tb{sup 3+} to Eu{sup 3+} in AlN powders; (8) emission from AlN powder samples codoped with (Eu{sup 3+} ,Tb{sup 3+} ) and (Dy{sup 3+}, Tm{sup 3+}); and (9) white emission from AlN codoped with Dy{sup 3+} and Tm{sup 3+}. We also extensively studied the stabilities of rare earth ions in GaN, and the nature of oxygen defects in GaN and its impact on the optical properties of the host material, using first principles method. Results from these theoretical calculations together with fluorescence measurements from the materials essentially proved the underlying concepts for generating white light using RE{sup 3+}-activated nitrides. For this project, we successfully built a horizontal MOVPE reactor and used it to deposit thin films of undoped and doped nitrides of GaN and InGaN, which is a very significant achievement. Since this reactor was designed and built by in-house experts, it could be easily modified and reassembled for specific research purposes. During this study, it was successfully modified for homogeneous distribution of rare earth ions in a deposited film. It will be an ideal tool for future research involving novel thin film material concepts. We examined carefully the suitability of various metal organic precursors for incorporating RE{sup 3+}. In order to avoid oxygen contamination, several oxygen-free RE{sup 3+} precursors were identified. Both oxygen-free and oxygen- containing metal organic precursors were used for certain rare earth ions (Eu{sup 3+}, Tb{sup 3+} and Er{sup 3+}). However, the suitability of any particular type of precursor for MOVPE deposition was not established during this study, and further study is needed. More intensive research in the future is needed to improve the film quality, and eliminate the separation of rare earth oxide phases during the deposition of thin films by MOVPE. The literature in the area of the chemistry of rare earth ions in nitrides is almost nonexistent, in spite of the significant research on luminescence of RE{sup 3+} in nitrides. Consequently, MOVPE as a method of deposition of RE{sup 3+}-activated nitrides is relatively unexplored. In the following sections of this report, the ou

Jan Talbot; Kailash Mishra

2007-12-31

298

Daphnia (zoomed on floating blood cells; low light)  

NSDL National Science Digital Library

The black cells are actually the well-defined blood cells of the Daphnia. The pumping heart pumps these cells throughout the body. We are able to see these cells due to the zooming capability of a microscope.

Katie Hale (CSUF;Biological Sciences)

2007-07-18

299

Structure-Guided Transformation of Channelrhodopsin into a Light-Activated Chloride Channel  

PubMed Central

Using light to silence electrical activity in targeted cells is a major goal of optogenetics. Available optogenetic proteins that directly move ions to achieve silencing are inefficient, pumping only a single ion per photon across the cell membrane rather than allowing many ions per photon to flow through a channel pore. Building on high-resolution crystal-structure analysis, pore vestibule modeling, and structure-guided protein engineering, we designed and characterized a class of channelrhodopsins (originally cation-conducting) converted into chloride-conducting anion channels. These tools enable fast optical inhibition of action potentials and can be engineered to display step-function kinetics for stable inhibition, outlasting light pulses and for orders-of-magnitude-greater light sensitivity of inhibited cells. The resulting family of proteins defines an approach to more physiological, efficient, and sensitive optogenetic inhibition. PMID:24763591

Berndt, Andre; Lee, Soo Yeun; Ramakrishnan, Charu; Deisseroth, Karl

2014-01-01

300

Biomechanical model produced from light-activated dental composite resins: a holographic analysis  

NASA Astrophysics Data System (ADS)

Light-activated dental composites, commonly applied in dentistry, can be used as excellent material for producing biomechanical models. They can be cast in almost any shape in an appropriate silicone mold and quickly solidified by irradiation with light in the blue part of the spectrum. In that way, it is possible to obtain any number of nearly identical casts. The models can be used to study the behavior of arbitrary structure under mechanical loads. To test the technique, a simple mechanical model of the tooth with a mesio-occluso-distal cavity was manufactured. Composite resin restoration was placed inside the cavity and light cured. Real-time holographic interferometry was used to analyze the contraction of the composite resin and its effect on the surrounding material. The results obtained in the holographic experiment were in good agreement with those obtained using the finite element method.

Panteli?, Dejan; Vasiljevi?, Darko; Blaži?, Larisa; Savi?-Ševi?, Svetlana; Muri?, Branka; Nikoli?, Marko

2013-11-01

301

Light activates binding of membrane proteins to chloroplast RNAs in Chlamydomonas reinhardtii.  

PubMed

Several membrane proteins were previously shown to bind to the 5' leader of the chloroplast psbC mRNA in the unicellular eukaryotic alga Chlamydomonas reinhardtii. This study showed that these proteins have affinity for AU-rich RNAs, as determined by competition experiments. In addition, their binding activities are enhanced 13-15-fold by light, and a 46 kDa protein is activated within 1-10 min. This activation could be mediated by the modulation of ADP pools by the light-dependent reactions of photosynthesis and ATP synthase because (1) two inhibitors that block ATP synthesis also prevent this activation and (2) ADP inhibits the RNA-binding activity of this protein in vitro. An inhibitor of Photosystem II diminishes this induction, suggesting that reducing potential generated by the photosynthetic electron transport chain modulates this RNA-binding activity. The RNA-binding activities of two proteins (of 46 and 47 kDa) are inhibited by Mg-protoporphyrin IX methyl ester in vitro suggesting they could be regulated by these intermediates in the chlorophyll biosynthetic pathway. PMID:12369632

Zerges, William; Wang, Shengwu; Rochaix, Jean-David

2002-10-01

302

Synchronous Activation of Cell Division by Light or Temperature Stimuli in the Dimorphic Yeast Schizosaccharomyces japonicus  

PubMed Central

Many fungi respond to light and regulate fungal development and behavior. A blue light-activated complex has been identified in Neurospora crassa as the product of the wc-1 and wc-2 genes. Orthologs of WC-1 and WC-2 have hitherto been found only in filamentous fungi and not in yeast, with the exception of the basidiomycete pathogenic yeast Cryptococcus. Here, we report that the fission yeast Schizosaccharomyces japonicus responds to blue light depending on Wcs1 and Wcs2, orthologs of components of the WC complex. Surprisingly, those of ascomycete S. japonicus are more closely related to those of the basidiomycete. S. japonicus reversibly changes from yeast to hyphae in response to environmental stresses. After incubation at 30°C, a colony of yeast was formed, and then hyphal cells extended from the periphery of the colony. When light cycles were applied, distinct dark- and bright-colored hyphal cell stripes were formed because the growing hyphal cells had synchronously activated cytokinesis. In addition, temperature cycles of 30°C for 12 h and 35°C for 12 h or of 25°C for 12 h and 30°C for 12 h during incubation in the dark induced a response in the hyphal cells similar to that of light. The stripe formation of the temperature cycles was independent of the wcs genes. Both light and temperature, which are daily external cues, have the same effect on growing hyphal cells. A dual sensing mechanism of external cues allows organisms to adapt to daily changes of environmental alteration. PMID:23873862

Okamoto, Sho; Furuya, Kanji; Nozaki, Shingo; Aoki, Keita

2013-01-01

303

Secular Light Curve of 2P/Encke: A Comet Active At Aphelion  

E-print Network

We present the secular light curve of comet 2P/Encke in two phase spaces, the log plot, and the time plot. The main conclusions of this work are: a) The comet shows activity at perihelion and aphelion, caused by two different active areas: Source 1, close to the South pole, active at perihelion, and Source 2, at the North pole, centered at aphelion. b) More than 18 physical parameters are measured from the secular light curves, many of them new, and are listed in the individual plots of the comet. Specifically we find for Source 1 the location of the turn on and turn off points of activity, RON= -1.63+-0.03 AU, ROFF= +1.49+-0.20 AU, TON= -87+-5 d, TOFF= +94+-15 d, the time lag, LAG(q)= 6+-1 d, the total active time, TACTIVITY= 181+-16 d, and the amplitude of the secular light curve, ASEC(1,1) = 4.8+-0.1 mag. c) From this information the photometric age and the time-age defined in Ferrin (Icarus 178, 493-516, 2005a, and Icarus, 185, 523-543, 2006), can be calculated, and we find P-AGE=97+-8 comet years and T-AGE= 103+-9 comet years (cy). Thus comet 2P/Encke is an old comet entering the methuselah stage (100 cy secular light curve is ASEC (1,Q) = 3.0+-0.2 mag. e) From a new phase diagram an absolute magnitude and phase coefficient for the nucleus are determined, and we find RNUC(1,1,0)= 15.05+-0.14, and betha= 0.066+-0.003. From this data we find a nucleus effective diameter DEFFE = 5.12(+2.5;-1.7) km. These values are not much different from previous determinations but exhibit smaller errors. Additional results appear in the full abstract.

Ignacio Ferrin

2008-06-12

304

Plasmonic color filters to decrease ambient light errors on active type dual band infrared image sensors  

NASA Astrophysics Data System (ADS)

In this paper, we proposed the plasmonic color filters to decrease ambient light errors on active type dual band infrared image sensors for a large-area multi-touch display system. Although the strong point of the touch display system in the area of education and exhibition there are some limits of the ambient light. When an unexpected ambient light incidents into the display the touch recognition system can make errors classifying the touch point in the unexpected ambient light area. We proposed a new touch recognition image sensor system to decrease the ambient light error and investigated the optical transmission properties of plasmonic color filters for IR image sensor. To find a proper structure of the plasmonic color filters we used a commercial computer simulation tool utilizing finite-difference time-domain (FDTD) method as several thicknesses and whit the cover passivation layer or not. Gold (Au) applied for the metal film and the dispersion information associated with was derived from the Lorentz-Drude model. We also described the mechanism applied the double band filter on the IR image sensors.

Lyu, Hong-Kun; Park, Young-Jin; Cho, Hui-Sup; Jo, Sung-Hyun; Lee, Hee-Ho; Shin, Jang-Kyoo

2014-09-01

305

Sustainable molecular oxygen activation with oxygen vacancies on the {001} facets of BiOCl nanosheets under solar light.  

PubMed

We demonstrate that oxygen vacancies on the {001} facets of BiOCl nanosheets can more sustainably activate molecular oxygen for organic pollutant removal under solar light than the TiO2 counterparts. The oxygen vacancies on the {001} facets of BiOCl nanosheets are effectively refreshed by UV light, and are also responsible for the efficient utilization of visible light to activate molecular oxygen, accounting for their long term stability and high efficiency. PMID:25329732

Li, Hao; Shi, Jingu; Zhao, Kun; Zhang, Lizhi

2014-11-01

306

Light and temperature dependence of the rate and degree of activation of pyruvate, Pi dikinase in vivo in maize  

Microsoft Academic Search

Activation of pyruvate,Pi dikinase by light was studied in leaf discs of maize which were illuminated for 1 h at light intensities ranging from approximately 3% to 50% of full sunlight and at temperatures of 10, 22.5, and 35°C. At the highest light intensity the degree of activation was similar and relatively independent of temperature between 10 and 35°C. Under

Gerald E. Edwards; Mayumi Ujihira; Tatsuo Sugiyama

1980-01-01

307

Visible-Light-Induced Bactericidal Activity of Titanium Dioxide Co-doped with Nitrogen and Silver  

PubMed Central

Titanium dioxide nanoparticles co-doped with nitrogen and silver (Ag2O/TiON) were synthesized by the sol-gel process and found to be an effective visible light driven photocatalyst. The catalyst showed strong bactericidal activity against Escherichia coli (E. coli) under visible light irradiation (?> 400 nm). In x-ray photoelectron spectroscopy and x-ray diffraction characterization of the samples, the as-added Ag species mainly exist as Ag2O. Spin trapping EPR study showed Ag addition greatly enhanced the production of hydroxyl radicals (•OH) under visible light irradiation. The results indicate that the Ag2O species trapped eCB? in the process of Ag2O/TiON photocatalytic reaction, thus inhibiting the recombination of eCB? and hVB+ in agreement with the stronger photocatalytic bactericidal activity of Ag2O/TiON. The killing mechanism of Ag2O/TiON under visible light irradiation is shown to be related to oxidative damages in the forms of cell wall thinning and cell disconfiguration. PMID:20726520

Wu, Pinggui; Xie, Rongcai; Imlay, Kari; Shang, Jian-Ku

2011-01-01

308

Novel light-activated antimicrobial coatings are effective against surface-deposited Staphylococcus aureus.  

PubMed

Aerosols constitute a major route of transmission for a wide range of infectious diseases in the hospital setting. The aim of this study was to determine the survival of Staphylococcus aureus on a light-activated antimicrobial coating. S. aureus suspended in phosphate-buffered saline (PBS), saliva, or horse serum was sprayed onto cellulose acetate coatings containing toluidine blue O and rose bengal and the survival of the organism on these surfaces was determined following 6 h of exposure to a 28-W domestic fluorescent lamp (light intensity = 3700 +/- 20 lux). Kills ranging from 78.9% (in horse serum) to 99.8% (in PBS) were obtained when the bacterial density on the coatings was approximately 10(5) colony-forming units/m(2). The results of this study have shown that a coating containing toluidine blue and rose bengal can achieve significant kills of S. aureus when illuminated by a domestic light source. Light-activated coatings could provide a simple, low-cost means of reducing the microbial load in hospitals and other facilities. PMID:18587617

Decraene, Valérie; Pratten, Jonathan; Wilson, Michael

2008-10-01

309

Redox and Light Control the Heme-Sensing Activity of AppA  

PubMed Central

ABSTRACT The DNA binding activity of the photosystem-specific repressor PpsR is known to be repressed by the antirepressor AppA. AppA contains a blue-light-absorbing BLUF domain and a heme-binding SCHIC domain that controls the interaction of AppA with PpsR in response to light and heme availability. In this study, we have solved the structure of the SCHIC domain and identified the histidine residue that is critical for heme binding. We also demonstrate that dark-adapted AppA binds heme better than light-excited AppA does and that heme bound to the SCHIC domain significantly reduces the length of the BLUF photocycle. We further show that heme binding to the SCHIC domain is affected by the redox state of a disulfide bridge located in the Cys-rich carboxyl-terminal region. These results demonstrate that light, redox, and heme are integrated inputs that control AppA’s ability to disrupt the DNA binding activity of PpsR. PMID:23982072

Yin, Liang; Dragnea, Vladimira; Feldman, George; Hammad, Loubna A.; Karty, Jonathan A.; Dann, Charles E.; Bauer, Carl E.

2013-01-01

310

DISTINCT PATTERNS OF NITRATE REDUCTASE ACTIVITY IN BROWN ALGAE: LIGHT AND AMMONIUM SENSITIVITY IN LAMINARIA DIGITATA IS ABSENT IN  

E-print Network

DISTINCT PATTERNS OF NITRATE REDUCTASE ACTIVITY IN BROWN ALGAE: LIGHT AND AMMONIUM SENSITIVITY and lowest in summer. This is the first report of NR activity in any alga that is not strongly regulated the regulation of NR by light that has been observed in other algae and higher plants. Key index words: ammonium

Berges, John A.

311

Effect of light-activation with different light-curing units and time intervals on resin cement bond strength to intraradicular dentin.  

PubMed

The aim of this study was to assess the bond strength of a resin cement to intraradicular dentin varying the light-curing unit and the moment at which the light was applied. Post spaces of endodontically treated canines were prepared. The roots were distributed into 6 groups (n=10) according to the light-curing unit and the moment of light exposure: I) Quartz tungsten halogen-600 mW/cm² (QTH) + immediate light activation (t0); II) QTH + light activation after 10 min (t10); III) Light-emitting diodes (LED)-800 mW/cm² (LED-800)+ t0; IV) LED-800 + t10; V) LED-1,500 mW/cm² (LED-1500)+ t0; VI) LED-1500 + t10. After post cementation, slices from coronal, middle and apical post/root regions were submitted to the push-out test and failure evaluation. It was verified that LED-800 (4.40 ± 3.00 MPa) and LED-1500 (4.67 ± 3.04 MPa) provided bond strength statistically superior to QTH (3.13 ± 1.76 MPa) (p<0.05), and did not differ from each other (p>0.05). There was no significant difference between t0 and t10 (p>0.05). Coronal post/root region (4.75 ± 3.10 MPa) presented significantly higher bond strength than the apical (3.32 ± 2.30 MPa) (p<0.05) and middle regions (4.14 ± 2.99 MPa) showed intermediate values. Adhesive failures were predominant when using QTH. Adhesive and mixed failures occurred more frequently in the apical region. Higher adhesion of the resin cement to intraradicular dentin was observed in the coronal region with LED light-activation, regardless of the moment of light exposure. PMID:23207850

Miguel-Almeida, Maria Eleonora; Azevedo, Mario Lucio da Costa; Rached-Júnior, Fuad Abi; Oliveira, Camila Favero; Silva, Ricardo Gariba; Messias, Danielle Cristine

2012-01-01

312

Real-time RMS active damping augmentation: Heavy and very light payload evaluations  

NASA Technical Reports Server (NTRS)

Controls-Structures Integration Technology has been applied to the Space Shuttle Remote Manipulator System (RMS) to improve on-orbit performance. The objective was to actively damp undesired oscillatory motions of the RMS following routine payload maneuvering and Shuttle attitude control thruster firings. Simulation of active damping was conducted in the real-time, man-in-the-loop Systems Engineering Simulator at NASA's Johnson Space Center. The simulator was used to obtain qualitative and quantitative data on active damping performance from astronaut operators. Using a simulated three-axis accelerometer mounted on the RMS, 'sensed' vibration motions were used to generate joint motor commands that reduced the unwanted oscillations. Active damping of the RMS with heavy and light attached payloads was demonstrated in this study. Five astronaut operators examined the performance of active damping following operator commanded RMS maneuvers and Shuttle thruster firings. Noticeable improvements in the damping response of the RMS with the heavy, Hubble Space Telescope payload and the very light, astronaut in Manipulator Foot Restraint payload were observed. The potential of active damping to aid in precisely maneuvering payloads was deemed significant.

Demeo, Martha E.; Gilbert, Michael G.; Lepanto, Janet A.; Flueckiger, Karl W.; Bains, Elizabeth M.; Jensen, Mary C.

1994-01-01

313

Carbon dioxide reduction via light activation of a ruthenium-Ni(cyclam) complex.  

PubMed

In this paper we report the synthesis of a chromophore-catalyst assembly designed for the photoreduction of carbon dioxide. The chromophore unit is made up of a ruthenium trisbipyridyl-like unit covalently attached to a nickel cyclam (cyclam = 1,4,8,11-tetraazacyclotetradecane) via a triazole ring. The intramolecular electron transfer activation of the catalyst unit by visible light was studied by nanosecond flash photolysis and EPR spectroscopy. In aqueous solutions (pH = 6.5), activation of the Ru(II)-Ni(II) modular assembly with 450 nm visible light in the presence of a sacrificial electron donor accomplishes the reduction of CO2 into CO and H2 in a ratio of 2.7 to 1. PMID:24600692

Herrero, Christian; Quaranta, Annamaria; El Ghachtouli, Sanae; Vauzeilles, Boris; Leibl, Winfried; Aukauloo, Ally

2014-06-28

314

Cystic acne improved by photodynamic therapy with short-contact 5-aminolevulinic acid and sequential combination of intense pulsed light and blue light activation.  

PubMed

Photodynamic therapy with short-contact 5-aminolevulinic acid (Levulan Kerastick, Dusa Pharmaceuticals, Inc.) and activation by intense pulsed light in an initial treatment and blue light in 3 subsequent treatments has resulted in significant improvement in severity of acne, reduction in the number of lesions, improvement in skin texture, and smoothing of scar edges in an Asian patient with severe (class 4) facial cystic acne and scarring. PMID:16302560

Melnick, Stuart

2005-01-01

315

Light-independent and light-dependent protochlorophyllide-reducing activities and two distinct NADPH-protochlorophyllide oxidoreductase polypeptides in mountain pine ( Pinus mugo )  

Microsoft Academic Search

Lower plants and gymnosperms synthesize chlorophyll and develop photosynthetically competent chloroplasts even when grown in the dark. In cell-free extracts of pine (Pinus mugo, Turra, ssp. mugo) seedlings, light-independent and light-dependent protochlorophyllide-reducing activities are present. Two distinct NADPH-protochlorophyllide-oxidoreductase (POR) polypeptides can be detected immunologically with an antiserum raised against the POR of barley. The subcellular localization and amounts of the

Christoph Forreiter; Klaus Apel

1993-01-01

316

Dawn–dusk simulation light therapy of disturbed circadian rest–activity cycles in demented elderly  

Microsoft Academic Search

We investigated whether low intensity dawn–dusk simulation (DDS), a ‘naturalistic’ form of light therapy designed to embed sleep in its accustomed phase, could improve the disturbed circadian rest–activity cycle, nocturnal sleep and and\\/or cognitive functions in dementia. A protocol of 3 weeks each of baseline, treatment and follow-up was completed by 13 patients (85yr old±5yr, MMSE 14±5; n=9 DDS versus

Paola Fontana Gasio; Kurt Kräuchi; Christian Cajochen; Eus van Someren; Isabelle Amrhein; Mona Pache; Egemen Savaskan; Anna Wirz-Justice

2003-01-01

317

Effect of light on the activity of motor cortex neurons during locomotion  

PubMed Central

The motor cortex plays a critical role in accurate visually guided movements such as reaching and target stepping. However, the manner in which vision influences the movement-related activity of neurons in the motor cortex is not well understood. In this study we have investigated how the locomotion-related activity of neurons in the motor cortex is modified when subjects switch between walking in the darkness and in light. Three adult cats were trained to walk through corridors of an experimental chamber for a food reward. On randomly selected trials, lights were extinguished for approximately four seconds when the cat was in a straight portion of the chamber's corridor. Discharges of 146 neurons from layer V of the motor cortex, including 51 pyramidal tract cells (PTNs), were recorded and compared between light and dark conditions. It was found that while cats’ movements during locomotion in light and darkness were similar (as judged from the analysis of three-dimensional limb kinematics and the activity of limb muscles), the firing behavior of 49% (71/146) of neurons was different between the two walking conditions. This included differences in the mean discharge rate (19%, 28/146 of neurons), depth of stride-related frequency modulation (24%, 32/131), duration of the period of elevated firing ([PEF], 19%, 25/131), and number of PEFs among stride-related neurons (26%, 34/131). 20% of responding neurons exhibited more than one type of change. We conclude that visual input plays a very significant role in determining neuronal activity in the motor cortex during locomotion by altering one, or occasionally multiple, parameters of locomotion-related discharges of its neurons. PMID:23680161

Armer, Madison C.; Nilaweera, Wijitha U.; Rivers, Trevor J.; Dasgupta, Namrata M.; Beloozerova, Irina N.

2013-01-01

318

The Effects of Period Mutations and Light on the Activity Rhythms of Drosophila melanogaster  

Microsoft Academic Search

Strains of Drosophila melanogaster homozygous for alleles of the period gene (per0, perL, per S, and per+) were reared for multiple generations either in light:dark cycles (LD), continuous illumination (LL), or chronic darkness (DD). The locomotor activity of adult flies from these cultures was monitored in either LL or DD. Flies that were reared and tested in DD had a

John M. Power; John M. Ringo; Harold B. Dowse

1995-01-01

319

The Reactive Light Yellow Dye Wastewater Treatment by Sewage Sludge-Based Activated Carbon  

Microsoft Academic Search

The paper is aim to discuss the dye wastewater treatment by sewage sludge-based adsorbent. The adsorbent derived from sewage sludge , which produced through phosphoric acid-microwave method, and commercia activated carbon (ACC) were tested in the process of the Reactive Light Yellow dye wastewater treatment. The effects of pH value, contact time and the adsorbents' amount on the adsorption efficiency

Yang Lijun; Dai Qunwei

2011-01-01

320

External bleaching therapy with activation by heat, light or laser—A systematic review  

Microsoft Academic Search

ObjectiveExternal bleaching procedures utilizing highly concentrated 30–35% hydrogen peroxide solutions or hydrogen peroxide releasing agents can be used for tooth whitening. To enhance or accelerate the whitening process, heat-activation of the bleaching agent by light, heat or laser is described in the literature. The aim of the present review article was to summarize and discuss the available information concerning the

Wolfgang Buchalla; Thomas Attin

2007-01-01

321

Effects of doping of metal cations on morphology, activity, and visible light response of photocatalysts  

Microsoft Academic Search

Effects of doping of metal cations into wide band gap semiconductor photocatalysts on morphology, visible light response, and photocatalytic performance were studied. Doping of lanthanide and alkaline earth ions improved activity of a NaTaO3 photocatalyst for water splitting. Lanthanum was the most effective dopant. The NaTaO3:La with a NiO cocatalyst gave 56% of a quantum yield at 270nm. This remarkable

Akihiko Kudo; Ryo Niishiro; Akihide Iwase; Hideki Kato

2007-01-01

322

Phase-shifting the light–dark cycle influences food-anticipatory activity in golden shiners  

Microsoft Academic Search

This study provides evidence that a circadian light-entrainable oscillator is at least partially involved in the timing of food-anticipatory activity (FAA) in a fish, the golden shiner, Notemigonus crysoleucas. Shoals of four golden shiners were fed for 11–20 days at a fixed daily time (either early night, midnight, late night, early day, midday, or late day). Most (78%) shoals developed

Martin Lague; Stephan G Reebs

2000-01-01

323

The role of carbon dioxide in light-activated hydrogen production by Chlamydomonas reinhardtii  

Microsoft Academic Search

Light-activated hydrogen and oxygen evolution as a function of CO2 concentration in helium were measured for the unicellular green alga Chlamydomonas reinhardtii. The concentrations were 58, 30, 0.8 and 0 ppm CO2. The objective of these experiments was to study the differential affinity of CO2\\/HCO3- for their respective Photosystem II and Calvin cycle binding sites vis-à-vis photoevolution of molecular oxygen

Roehl M. Cinco; Jean M. MacInnis; Elias Greenbaum

1993-01-01

324

Effects of temperature and photosynthetic inhibitors on light activation of C4-phosphoenolpyruvate carboxylase.  

PubMed

Phosphoenolpyruvate carboxylase from leaves of the C4 plant Setaria verticillata (L.) Beauv. is activated by light; day levels of activity are reached after 30 minutes of illumination. Photoactivation is prevented by inhibitors of photosynthetic electron flow or of photophosphorylation and by D,L-glyceraldehyde, which inhibits the reductive pentose phosphate pathway.Although the extractable activity in the dark is not affected by temperature the photoactivation is prevented when both illumination and extraction are done under low temperature (5 C). High temperature (30 C) during either illumination or extraction is needed for activation. Once the enzyme is photoactivated at 30 C, a transfer of the leaves to 5 C does not abolish the extra activity.The results suggest that both unimpaired electron flow and photophosphorylation are prerequisites for the activation of phosphoenolpyruvate carboxylase. Low temperature apparently suppresses either the transport to the cytoplasm of a photosynthetic intermediate or the activating reaction itself. The inclusion of phosphoenolpyruvate in the extraction medium increases the night activity.On the basis of the available information, it is suggested that phosphoenolpyruvate could be the activator in vivo. In that case, the activation of phosphoenolpyruvate carboxylase would depend on internal CO2 level and prior photoactivation of both pyruvate, orthophosphate, dikinase and NADP malate dehydrogenase. PMID:24429530

Samaras, Y; Manetas, Y; Gavalas, N A

1988-06-01

325

Biodiversity and importance of floating weeds of Dara Ismail, Khan District of KPK, Pakistan.  

PubMed

The present paper is based on the results of taxonomic research work conducted in Dera Ismail Khan District of KPK, Pakistan, during 2005 - 2007. The area was extensively surveyed in order to collect floating aquatic weeds. From the study area 11 floating aquatic weed species belonging to 9 genera and 9 families were collected and identified in the light of available literature. These plants include Bryophytes: 1 species, Ricciocarpus natans (L.) Corda; Pteridophytes: 2 species, Azolla pinnata R.Br. and Marselia quadrifolia L., and Spermatophytes: 8 species, Lemna aequinoctialis Welw., L. gibba L., Marselia quadrifoliata L. Nelumbo nucifera Gaerth., Nymphoides cristata (Roxb.) O. Ketze. Nymphoides indica (L.) Kuntze:, Pistia stratiotes L. Potamogeton nodosus Poiret and Spirodela polyrrhiza (L.) Schleid. Floating weeds on one hand cause serious problems and on the other hand they are used for various purposes. Data inventory consists of botanical name, family, major group, habit and habitat, flowering period, availability, distribution in D.I.Khan, Pakistan and world, beneficial and harmful effects. Key to the floating aquatic species of the area was developed for easy and correct identification and differentiation. PMID:22754062

Marwat, Sarfaraz Khan; Khan, Mir Ajab; Fazal-ur-Rehman; Ahmad, Mushtaq; Zafar, Muhammad

2011-01-01

326

Influence of Green, Red and Blue Light Emitting Diodes on Multiprotein Complex Proteins and Photosynthetic Activity under Different Light Intensities in Lettuce Leaves (Lactuca sativa L.)  

PubMed Central

The objective of this study was to investigate the response of light emitting diodes (LEDs) at different light intensities (70 and 80 for green LEDs, 88 and 238 for red LEDs and 80 and 238 ?mol m?2 s?1 for blue LEDs) at three wavelengths in lettuce leaves. Lettuce leaves were exposed to (522 nm), red (639 nm) and blue (470 nm) LEDs of different light intensities. Thylakoid multiprotein complex proteins and photosynthetic metabolism were then investigated. Biomass and photosynthetic parameters increased with an increasing light intensity under blue LED illumination and decreased when illuminated with red and green LEDs with decreased light intensity. The expression of multiprotein complex proteins including PSII-core dimer and PSII-core monomer using blue LEDs illumination was higher at higher light intensity (238 ?mol m?2 s?1) and was lowered with decreased light intensity (70–80 ?mol m?2 s?1). The responses of chloroplast sub-compartment proteins, including those active in stomatal opening and closing, and leaf physiological responses at different light intensities, indicated induced growth enhancement upon illumination with blue LEDs. High intensity blue LEDs promote plant growth by controlling the integrity of chloroplast proteins that optimize photosynthetic performance in the natural environment. PMID:24642884

Muneer, Sowbiya; Kim, Eun Jeong; Park, Jeong Suk; Lee, Jeong Hyun

2014-01-01

327

Floating reference frames for flexible spacecraft  

NASA Technical Reports Server (NTRS)

Floating reference frames which move with the flexible body under dynamic analysis offer the advantages of a linear vibration analysis in the presence of large system rotations. When the deformations of an elastic continuum are expanded in terms of the free-free modes on an unconstrained system, the rigid body modes are found to be fixed in a reference frame called the Tisserand frame, with respect to which the relative momentum is zero. This result also guarantees the independence of small variations of frame motions and coordinates for all modes with nonzero natural frequencies, a condition which can greatly simplify the formulation of equations of motion. A Modified Tisserand Constraint is introduced in order to define a floating reference frame with similar properties for an elastic body which contains spinning rotors.

Canavin, J. R.; Likins, P. W.

1977-01-01

328

Preparation of floating pellets with verapamil hydrochloride.  

PubMed

The aim of this paper is to prepare a floating drug formulation in a gelatin capsule filled with tens of pellets with verapamil hydrochloride (VH) in a dose of 40 mg. The better solubility of VH in an acidic environment of the stomach may result in a greater amount of the drug absorbed. Pellets were prepared by wet granulation of a powder mixture, spheronization of the granulated mass and coating of the cores with aqueous dispersions of polymethylmethacrylate. Sodium hydrocarbonate contained in pellet cores ensures the flotation effect. Proper rate of VH release from pellets was obtained by a coating film of 25-105 microm thickness. Pellets of 1.25-1.6 mm size with a film of 75-85 microm thickness of considerably constant rate released the whole dose of VH in 6 h. During that time the pellets floated on the surface of the receptor solution. PMID:15481243

Sawicki, Wies?aw; G?ód, Joanna

2004-01-01

329

OCD metrology by floating n/k  

NASA Astrophysics Data System (ADS)

In this paper, one of the major contributions to the OCD metrology error, resulting from within-wafer variation of the refractive index/extinction coefficient (n/k) of the substrate, is identified and quantified. To meet the required metrology accuracy for the 65-nm node and beyond, it is suggested that n/k should be floating when performing the regression for OCD modeling. A feasible way of performing such regression is proposed and verified. As shown in the presented example, the measured CDU (3?) with n/k fixed and n/k floating is 1.94 nm and 1.42 nm, respectively. That is, the metrology error of CDU committed by assuming n/k fixed is more than 35% of the total CDU.

Yu, Shinn-Sheng; Huang, Jacky; Ke, Chih-Ming; Gau, Tsai-Sheng; Lin, Burn J.; Yen, Anthony; Lane, Lawrence; Vuong, Vi; Chen, Yan

2007-03-01

330

Integral floating display systems for augmented reality.  

PubMed

Novel integral floating three-dimensional (3D) display methods are proposed for implementing an augmented reality (AR) system. The 3D display for AR requires a long-range focus depth and a see-though property. A system that adopts a concave lens instead of a convex lens is proposed for realizing the integral floating system with a long working distance using a reduced pixel pitch of the elemental image. An investigation that reveals that the location of the central depth plane is restricted by the pixel pitch of the display device is presented. An optical see-through system using a convex half mirror is also proposed for providing 3D images with a proper accommodation response. The concepts of the proposed methods are explained and the validity of system is proved by the experimental results. PMID:22722298

Hong, Jisoo; Min, Sung-Wook; Lee, Byoungho

2012-06-20

331

A new concept in floating production systems  

SciTech Connect

This paper describes a tandem hull floating production platform which combines the large deck space and high payload carrying advantages of a monohull vessel with some of the low wave induced motion characteristics that are typical of semisubmersible vessels. The basic features of the tandem hull platform are presented and comparisons made with the motion characteristics of various other hull forms. The model tests and computer simulation programs used in the design of the tandem hull platform are described and the results presented. Assessments are made of the capital and operating costs of a tandem hull production system and comparisons made with those of other floating production systems that are based on alternative hull forms.

Patel, M.H.; Montgomery, J.I.; Worley, M.S.

1984-10-01

332

Preparation of floating microspheres for fish farming.  

PubMed

The aim of this study was to develop floating microspheres with practical applications to fish farming. Each microsphere with a central hollow cavity was prepared using a solvent diffusion and evaporation method with Eudragit E100. Various manufacturing parameters were investigated by single factor method. The macrolide antibiotic josamycin was selected as a model drug. The loading efficiency of the drug in the microspheres was 64.7%. In the release study, virtually none of the drug was released into the fresh water whereas the entire drug was released from the josamycin-loaded microspheres into the simulated gastric fluid of rainbow trout (pH 2.7). The buoyancy was excellent with approximately 90% of the microspheres still floating after 24h. PMID:17485183

Nepal, Pushp R; Chun, Myung-Kwan; Choi, Hoo-Kyun

2007-08-16

333

Active display and encoding by integrated plasmonic polarizer on light-emitting-diode.  

PubMed

An electrical pumped microscopic active display with integration of plasmonic polarizer and light-emitting-diode is proposed. Thanks to the strong polarized emission through the rectangular nanoholes, well designed pixels with respect to different polarizations are engineered, which give rise to flexible and controllable active display. As results, polarization multiplexed letter encoding, single and double gray-scale images and animation movies are successfully realized. Our results demonstrate a new strategy in electro-optical integration and indicate potential applications in designing new type of microscopic electro-optical devices. PMID:24008314

Wang, L; Li, T; Guo, R Y; Xia, W; Xu, X G; Zhu, S N

2013-01-01

334

Synthesis of highly active visible-light-driven colloidal silver orthophosphate  

NASA Astrophysics Data System (ADS)

The present study deals with the synthesis of highly uniform and spherical visible-light-driven colloidal silver phosphate (Ag 3PO 4) with the size of ˜200 nm. These colloidal particles showed excellent photocatalytic activity for the removal of different dyes and pesticide under sunlight-type excitation. The photocatalytic activity of these particles, obtained by colloidal method, was found to be much higher than silver phosphate obtained by precipitation method, or titanium dioxide, or zinc oxide under identical conditions. The effect of catalyst amount and recyclability on the photocatalytic response of Ag 3PO 4 was also investigated.

Khan, A.; Qamar, M.; Muneer, M.

2012-01-01

335

Simultaneous whole-animal 3D-imaging of neuronal activity using light field microscopy  

E-print Network

3D functional imaging of neuronal activity in entire organisms at single cell level and physiologically relevant time scales faces major obstacles due to trade-offs between the size of the imaged volumes, and spatial and temporal resolution. Here, using light-field microscopy in combination with 3D deconvolution, we demonstrate intrinsically simultaneous volumetric functional imaging of neuronal population activity at single neuron resolution for an entire organism, the nematode Caenorhabditis elegans. The simplicity of our technique and possibility of the integration into epi-fluoresence microscopes makes it an attractive tool for high-speed volumetric calcium imaging.

Prevedel, R; Hoffmann, M; Pak, N; Wetzstein, G; Kato, S; Schrödel, T; Raskar, R; Zimmer, M; Boyden, E S; Vaziri, A

2014-01-01

336

Active display and encoding by integrated plasmonic polarizer on light-emitting-diode  

PubMed Central

An electrical pumped microscopic active display with integration of plasmonic polarizer and light-emitting-diode is proposed. Thanks to the strong polarized emission through the rectangular nanoholes, well designed pixels with respect to different polarizations are engineered, which give rise to flexible and controllable active display. As results, polarization multiplexed letter encoding, single and double gray-scale images and animation movies are successfully realized. Our results demonstrate a new strategy in electro-optical integration and indicate potential applications in designing new type of microscopic electro-optical devices. PMID:24008314

Wang, L.; Li, T.; Guo, R. Y.; Xia, W.; Xu, X. G.; Zhu, S. N.

2013-01-01

337

Increased antioxidant activity and changes in phenolic profile of Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) specimens grown under supplemental blue light.  

PubMed

Antioxidant compounds protect plants against oxidative stress caused by environmental conditions. Different light qualities, such as UV-A radiation and blue light, have shown positive effects on the production of phenols in plants. Kalanchoe pinnata (Lamarck) Persoon (Crassulaceae) is used for treating wounds and inflammations. Some of these beneficial effects are attributed to the antioxidant activity of plant components. We investigated the effects of blue light and UV-A radiation supplementation on the total phenol content, antioxidant activity and chromatographic profile of aqueous extracts from leaves of K. pinnata. Monoclonal plants were grown under white light, white plus blue light and white plus UV-A radiation. Supplemental blue light improved the antioxidant activity and changed the phenolic profile of the extracts. Analysis by HPLC of supplemental blue-light plant extracts revealed a higher proportion of the major flavonoid quercetin 3-O-?-L-arabinopyranosyl (1?2) ?-L-rhamnopyranoside, as well as the presence of a wide variety of other phenolic substances. These findings may explain the higher antioxidant activity observed for this extract. Blue light is proposed as a supplemental light source in the cultivation of K. pinnata, to improve its antioxidant activity. PMID:23057576

Nascimento, Luana B S; Leal-Costa, Marcos V; Coutinho, Marcela A S; Moreira, Nattacha dos S; Lage, Celso L S; Barbi, Nancy dos S; Costa, Sônia S; Tavares, Eliana S

2013-01-01

338

A 600MHz superscalar floating point processor  

Microsoft Academic Search

The floating point unit of a 600MHz, 60 SpecFP95 (est.), out-of-order, superscalar RISC Alpha micro-processor is described. The unit has two independent pipelines for multiply and add\\/subtract instructions, and iterative divide and square root circuits. It implements both IEEE and VAX data formats and is fabricated in a 2.2v, 0.35µm CMOS process.

M. Matson; R. Badeau; J. Clouser; R. Dupcak; B. Grundmann; M. Lamere; S. Samudrala; R. Allmon; N. Fairbanks

1998-01-01

339

Verification of Floating-Point Adders  

Microsoft Academic Search

The floating-point(FP) division bug in Intel's Pentium proc essor and the overflow flag erratum of the FIST instruction in Intel's Pe ntium Pro and Pen- tium II processor have demonstrated the importance and the difficulty of verifying FP arithmetic circuits. In this paper, we present the verific ation of FP adders with reusable specifications, using extended word-level SMV, wh ich

Yirng-an Chen; Randal E. Bryant

1998-01-01

340

Floating vs flying: A propulsion energy comparison  

NASA Technical Reports Server (NTRS)

Floating craft are compared to those that fly. Drag/weight for floaters is shown to be proportional to v squared/L, while for flyers it is independent of size and speed. The transportation market will therefore assign airships to lower speeds than airplanes, and will favor large airship sizes. Drag of an airship is shown to be only 11 percent of submarine drag at equal displacement and speed, raising the possibility that airships can compete with some types of ships.

Marbury, F.

1975-01-01

341

Pigmented free-floating iris cysts  

Microsoft Academic Search

Free-floating iris cysts are rare. These cysts may be located in the vitreous or the anterior chamber. Anterior chamber cysts can be idiopathic or induced by trauma or surgery. Vitreous cysts may be associated with the remnants of the hyaloid system and therefore be congenital, or can result from trauma or ocular disease.Case 1: An 8-year-old girl presented for routine

Gurdeep Singh; Kalpana Narendran; Veerappan R Saravanan; V Narendran

2007-01-01

342

Floating Ice: Grades K-1: Electronic Book  

NSDL National Science Digital Library

This informational text discusses the unique property of ice - that it floats in liquid water. Students focus on real-world examples and how ice is necessary for life in the polar regions. The text is written at a kindergarten through grade one reading level. This is an onscreen version that contains recorded narration allowing students to listen to the text as they read along. Highlighted vocabulary words have individually recorded definitions heard by clicking on the links.

Fries-Gaither, Jessica

343

Maintaining competency for float nursing staff.  

PubMed

Orienting staff to multiple areas is challenging, as is maintaining multiple competencies, which might be used infrequently. Creating a strategy to regularly assess needed competencies to maintain a highly skilled pool of nurses, prepared to float to multiple areas, is critical to supporting flexible staffing. A plan for how to achieve this complex analysis is described and can be translated to other complex environments. PMID:25036084

Overman, Kimberly; Hauver, Jeni; McKay, Jennifer; Aucoin, Julia

2014-01-01

344

Fast Decimal Floating-Point Division  

Microsoft Academic Search

Abstract—A new implementation for decimal floating-point (DFP) division is introduced. The algorithm is based on high-radix SRT division, with the recurrence in a new decimal signed-digit format. Quotient digits are selected using comparison multiples, where the magnitude of the quotient digit is calculated by comparing the truncated partial remainder with limited precision multiples of the divisor. The sign is determined

Hooman Nikmehr; Braden Phillips; Cheng-chew Lim

2006-01-01

345

The effects of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth on the growth of submerged macrophytes  

Microsoft Academic Search

In laboratory experiments, the growth characteristics of the submerged species Elodea nuttallii (Planch.) St. John and Potamogeton crispus L. were assessed in the presence and absence of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth. Light penetration and the development of pH and dissolved oxygen differences were monitored. The growth of P. crispus was suppressed much more than

Rachel A. Janes; John W. Eaton; Keith Hardwick

1996-01-01

346

Laser light induced modulations in metabolic activities in human brain cancer  

NASA Astrophysics Data System (ADS)

The role of low visible or near infra-red laser intensity in suppressing metabolic activity of malignant human brain cancer (glioblastoma) cells was investigated through the application of either a continuous wave 633nm HeNe or a pulsed picosecond 1,552nm wavelength laser. Human glioblastomas were exposed in their growth culture medium with serum for several energy doses. For both types of laser exposures the glioblastomas exhibited a maximal decline in the metabolic activity relative to their respective sham control counterparts at 10 J/cm2. The cellular metabolic activities for various treatment doses were measured through the colorimetric MTS metabolic assay after the laser exposure. Interestingly, addition of (the enzyme) catalase in the growth medium prior to the laser exposure was found to diminish the laser induced metabolic suppression for all fluence treatment conditions, thus suggesting a functional role of H IIO II in the metabolic suppression. Taken together, our findings reveal that visible or near infra-red low level light exposures could potentially be a viable tool in reducing the metabolic activity of cancers; evidence at hand implicates a role of light induced H IIO II in bringing about in part, suppression in the metabolic activity. Due to the cellular "biphasic" response to the laser exposure, further research needs to be undertaken to determine exposure parameters which would optimize metabolic and cellular growth suppression in-vivo.

Tata, Darrell B.; Waynant, Ronald W.

2008-03-01

347

Phase-shifting the light-dark cycle influences food-anticipatory activity in golden shiners.  

PubMed

This study provides evidence that a circadian light-entrainable oscillator is at least partially involved in the timing of food-anticipatory activity (FAA) in a fish, the golden shiner, Notemigonus crysoleucas. Shoals of four golden shiners were fed for 11-20 days at a fixed daily time (either early night, midnight, late night, early day, midday, or late day). Most (78%) shoals developed peaks of FAA during that period of time. Food was then withheld for 7 days, and the light-dark (LD) cycle was either advanced or delayed by 6 h on the first of those days. The activity waveform of most (53-58%) shoals shifted along with the LD cycle, as indicated by significant correlation coefficients between pre- and postshift waveforms plotted relative to LD. Nonsignificant correlations were linked to low activity levels rather than to persistence of the activity peak at the old clock time. Activity shifts were gradual, taking 2-4 days, which indicates that the underlying mechanism is circadian rather than hourglass. PMID:10978478

Lague, M; Reebs, S G

348

Capillary induced buckling of floating sheets  

NASA Astrophysics Data System (ADS)

When a water droplet is deposited over a thin floating sheet, radial wrinkles appear in the vicinity of the droplet as a result of capillary forces exerted at the contact line [1]. However, determining the stress state at the contact line is still challenging and limits the full description of the wrinkling pattern. In order to avoid this contact line ambiguities, we propose the experimental study of the buckling of a macroscopic annulus floating on the surface of water and submitted to a difference in surface tension between its inner and outer edges. This particular configuration allows to generate radial wrinkles on the membrane with well defined border conditions. The topography of the wrinkled patterns are precisely measured using a synthetic Schlieren technique. Based on the standard buckling theory, we develop scaling laws for the buckling threshold of the annulus as well as for the wave length and radial extension of the wrinkles, which are compared to our experimental results and numerical simulations. [4pt] [1] J. Huang, M. Juszkiewicz, W.H. de Jeu, E. Cerda, T. Emrick, N. Menon, and T.P. Russell. Capillary wrinkling of floating thin polymer films. Science, 317(5838):650-653, 2007.

Pineirua, Miguel; Bico, Jose; Roman, Benoit; Menon, Narayanan

2012-02-01

349

Liquid encapsulated float zone process and apparatus  

NASA Technical Reports Server (NTRS)

The process and apparatus for growing crystals using float zone techniques are described. A rod of crystalline materials is disposed in a cylindrical container, leaving a space between the rod and container walls. This space is filled with an encapsulant, selected to have a slightly lower melting point than the crystalline material. The rod is secured to a container end cap at one end and to a shaft at its other end. A piston slides over the rod and provides pressure to prevent loss of volatile components upon melting of the rod. Prior to melting the rod the container is first heated to melt the encapsulant, with any off-gas from this step being vented to a cavity behind the piston. The piston moves slightly forward owing to volume change upon melting of the encapsulant, and the vent passageway is closed. The container is then moved longitudinally through a heated zone to progressively melt sections of the rod as in conventional float zone processes. The float zone technique may be used in the microgravity environment of space.

Naumann, Robert J. (inventor); Frazier, Donald O. (inventor); Lehoczky, Sandor L. (inventor); Vlasse, Marcus (inventor); Facemire, Barbara R. (inventor)

1988-01-01

350

Floating debris in the Mediterranean Sea.  

PubMed

Results from the first large-scale survey of floating natural (NMD) and anthropogenic (AMD) debris (>2 cm) in the central and western part of the Mediterranean Sea are reported. Floating debris was found throughout the entire study area with densities ranging from 0 to 194.6 items/km(2) and mean abundances of 24.9 AMD items/km(2) and 6.9 NMD items/km(2) across all surveyed locations. On the whole, 78% of all sighted objects were of anthropogenic origin, 95.6% of which were petrochemical derivatives (i.e. plastic and styrofoam). Maximum AMD densities (>52 items/km(2)) were found in the Adriatic Sea and in the Algerian basin, while the lowest densities (<6.3 items/km(2)) were observed in the Central Tyrrhenian and in the Sicilian Sea. All the other areas had mean densities ranging from 10.9 to 30.7 items/km(2). According to our calculations, more than 62 million macro-litter items are currently floating on the surface of the whole Mediterranean basin. PMID:25127501

Suaria, Giuseppe; Aliani, Stefano

2014-09-15

351

Antileishmanial effect of silver nanoparticles and their enhanced antiparasitic activity under ultraviolet light  

PubMed Central

Leishmaniasis is a protozoan vector-borne disease and is one of the biggest health problems of the world. Antileishmanial drugs have disadvantages such as toxicity and the recent development of resistance. One of the best-known mechanisms of the antibacterial effects of silver nanoparticles (Ag-NPs) is the production of reactive oxygen species to which Leishmania parasites are very sensitive. So far no information about the effects of Ag-NPs on Leishmania tropica parasites, the causative agent of leishmaniasis, exists in the literature. The aim of this study was to investigate the effects of Ag-NPs on biological parameters of L. tropica such as morphology, metabolic activity, proliferation, infectivity, and survival in host cells, in vitro. Consequently, parasite morphology and infectivity were impaired in comparison with the control. Also, enhanced effects of Ag-NPs were demonstrated on the morphology and infectivity of parasites under ultraviolet (UV) light. Ag-NPs demonstrated significant antileishmanial effects by inhibiting the proliferation and metabolic activity of promastigotes by 1.5- to threefold, respectively, in the dark, and 2- to 6.5-fold, respectively, under UV light. Of note, Ag-NPs inhibited the survival of amastigotes in host cells, and this effect was more significant in the presence of UV light. Thus, for the first time the antileishmanial effects of Ag-NPs on L. tropica parasites were demonstrated along with the enhanced antimicrobial activity of Ag-NPs under UV light. Determination of the antileishmanial effects of Ag-NPs is very important for the further development of new compounds containing nanoparticles in leishmaniasis treatment. PMID:22114501

Allahverdiyev, Adil M; Abamor, Emrah Sefik; Bagirova, Malahat; Ustundag, Cem B; Kaya, Cengiz; Kaya, Figen; Rafailovich, Miriam

2011-01-01

352

Active control of slow light on a chip with photonic crystal waveguides.  

PubMed

It is known that light can be slowed down in dispersive materials near resonances. Dramatic reduction of the light group velocity-and even bringing light pulses to a complete halt-has been demonstrated recently in various atomic and solid state systems, where the material absorption is cancelled via quantum optical coherent effects. Exploitation of slow light phenomena has potential for applications ranging from all-optical storage to all-optical switching. Existing schemes, however, are restricted to the narrow frequency range of the material resonance, which limits the operation frequency, maximum data rate and storage capacity. Moreover, the implementation of external lasers, low pressures and/or low temperatures prevents miniaturization and hinders practical applications. Here we experimentally demonstrate an over 300-fold reduction of the group velocity on a silicon chip via an ultra-compact photonic integrated circuit using low-loss silicon photonic crystal waveguides that can support an optical mode with a submicrometre cross-section. In addition, we show fast (approximately 100 ns) and efficient (2 mW electric power) active control of the group velocity by localized heating of the photonic crystal waveguide with an integrated micro-heater. PMID:16267549

Vlasov, Yurii A; O'Boyle, Martin; Hamann, Hendrik F; McNab, Sharee J

2005-11-01

353

Differential hypothalamic tyrosine hydroxylase distribution and activation by light in adult mice reared under different light conditions during the suckling period.  

PubMed

In mammals, early light experience during a critical period within the first 3 weeks of postnatal development has long-lasting effects on circadian locomotor activity behaviour and neuropeptide expression in the suprachiasmatic nucleus (SCN) of the hypothalamus, site of the principal pacemaker. Dopamine is thought to be involved in the modulation of photic input within the SCN and in tadpoles, the expression of tyrosine hydroxylase (TH), a rate-limiting enzyme in the synthesis of dopamine, in the SCN is altered by previous light history. We thus hypothesised that dopaminergic neurons may be important for the development of the adapted responses to light that we have previously observed. To test this, we raised mice in either constant darkness, 12:12 h light-dark cycles or constant light during the first 3 weeks after birth, and later examined the expression of TH and FOS in the hypothalamus of these mice as adults, both in the dark and after exposure to a light pulse. We found that early light experience affects TH and FOS expression, both baseline levels and in response to a light pulse, in brain areas which are directly connected to the SCN, and are associated with the circadian control of neuroendocrine function. Therefore, our results suggest that the long-lasting alterations induced by early light environment on several hypothalamic nuclei may be relayed through the SCN, and that TH-expressing cells may play a role in conveying/establishing these alterations. These data suggest a role of early light experience in the regulation of future hormonal homeostasis and circadian behaviour. PMID:21509614

Brooks, Elisabeth; Waters, Elizabeth; Farrington, Lydia; Canal, Maria Merce

2011-11-01

354

Dark/light modulation of ribulose bisphosphate carboxylase activity in plants from different photosynthetic categories  

SciTech Connect

Ribulose bisphosphate carboxylase/oxygenase (RuBPCase) from several plants had substantially greater activity in extracts from light-exposed leaves than dark leaves, even when the extracts were incubated in vitro with saturating HCO/sub 3//sup -/ and Mg/sup 2 +/ concentrations. This occurred in Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Panicum bisulcatum, and P. hylaeicum (C/sub 3/); P. maximum (C/sub 4/ phosphoenolpyruvate carboxykinase); P. milioides (C/sub 3//C/sub 4/); and Bromelia pinguin and Ananas comosus (Crassulacean acid metabolism). Little or no difference between light and dark leaf extracts of RuBPCase was observed in Triticum aestivum (C/sub 3/); P. miliaceum (C/sub 4/ NAD malic enzyme); Zea mays and Sorghum bicolor (C/sub 4/ NADP malic enzyme); Moricandia arvensis (C/sub 3//C/sub 4/); and Hydrilla verticillata (submersed aquatic macrophyte). It is concluded that, in many plants, especially Crassulacean acid metabolism and C/sub 3/ species, a large fraction of ribulose-1,5-bisphosphate carboxylase/oxygenase in the dark is in an inactivatable state that cannot respond to CO/sub 2/ and Mg/sup 2 +/ activation, but which can be converted to an activatable state upon exposure of the leaf to light. 16 references, 2 tables.

Vu, J.C.V.; Allen, L.H. Jr.; Bowes, G.

1984-11-01

355

The study of visible light active bismuth modified nitrogen doped titanium dioxide photocatlysts: Role of bismuth  

NASA Astrophysics Data System (ADS)

Bismuth modified nitrogen doped TiO2 nanoparticles have been successfully prepared by two steps synthesis route which includes hydrothermal and impregnation hydrolysis method. Samples were characterized using X-ray diffraction (XRD), N2 physical adsorption, Transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier Transmission Infrared (FTIR), Raman, X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy (PLS) technologies. The preparatory method afforded the production of well crystallized spherical Bi modified N-doped TiO2 nanoparticles with varied amounts of Bi content. XRD analysis results reveal that Bi exists as rare metastable Bi20TiO32 which started to surface at Bi loading content of 7 mol% in relation to Ti ions. All Bi modified N-TiO2 samples exhibited higher photocatalytic activity toward degradation of 2,4-DCP over N-TiO2 under visible light irradiation. The sample with 10% composition of the Bi20TiO32 exhibited the highest activity. The superior photocatalytic performance of 10%Bi/N-TiO2 is attributed to high visible light absorption as well as effective charge carrier separation. Therefore, the role of Bi species in the N-TiO2 is improvement of visible light harvesting and facilitation of charge carrier separation hence alleviating electron-hole recombination.

Bagwasi, Segomotso; Niu, Yuxiao; Nasir, Muhammad; Tian, Baozhu; Zhang, Jinlong

2013-01-01

356

Dairy wastewater treatment using an activated sludge-microalgae system at different light intensities.  

PubMed

A microalgae-bacteria system was used for dairy industry wastewater treatment in sequenced batch mode in a photobioreactor. The research investigated the influence of two light intensities: 360 and 820 ?mol m(-2)s(-1) on treatment performances, microalgal cell recovery and dynamics of the protozoan community. Results showed that the light intensity of 360 ?mol m(-2)s(-1) was found to be insufficient to support photosynthetic activity after the increase of bacterial biomass leading to the decrease of organic matter and ammonium removal efficiencies from 95 to 78% and 95 to 41%, respectively. Maximum microalgal cells recovery was about 63%. Continuous modification in the protozoan community was also noticed during this test. Increasing the light intensity to 820 ?mol m(-2)s(-1) led to better microalgal cells recovery (up to 88%) and improved treatment performances. However, the decrease of protozoan richness to small flagellates and free-swimming ciliates was noticed. Moreover, the developed protozoan trophic network was found to be different from that identified in the conventional activated sludge system. The study emphasized that high increase of bacterial biomass promoted in nutrient- and organic matter-rich wastewater can strongly affect the treatment performances as a result of the shadow effect produced on the photoautotrophic microalgae aggregates. PMID:24759517

Tricolici, O; Bumbac, C; Patroescu, V; Postolache, C

2014-01-01

357

Accurate measurement of volume and shape of resting and activated blood platelets from light scattering  

NASA Astrophysics Data System (ADS)

We introduce a novel approach for determination of volume and shape of individual blood platelets modeled as an oblate spheroid from angle-resolved light scattering with flow-cytometric technique. The light-scattering profiles (LSPs) of individual platelets were measured with the scanning flow cytometer and the platelet characteristics were determined from the solution of the inverse light-scattering problem using the precomputed database of theoretical LSPs. We revealed a phenomenon of parameter compensation, which is partly explained in the framework of anomalous diffraction approximation. To overcome this problem, additional a priori information on the platelet refractive index was used. It allowed us to determine the size of each platelet with subdiffraction precision and independent of the particular value of the platelet aspect ratio. The shape (spheroidal aspect ratio) distributions of platelets showed substantial differences between native and activated by 10 ?M adenosine diphosphate samples. We expect that the new approach may find use in hematological analyzers for accurate measurement of platelet volume distribution and for determination of the platelet activation efficiency.

Moskalensky, Alexander E.; Yurkin, Maxim A.; Konokhova, Anastasiya I.; Strokotov, Dmitry I.; Nekrasov, Vyacheslav M.; Chernyshev, Andrei V.; Tsvetovskaya, Galina A.; Chikova, Elena D.; Maltsev, Valeri P.

2013-01-01

358

Effect of Light and NO3? on Wheat Leaf Phosphoenolpyruvate Carboxylase Activity  

PubMed Central

Phosphoenolpyruvate carboxylase (PEPcase) activity was studied in excised leaves of wheat (Triticum aestivum L.) in the dark and in the light, in presence of either N-free (low-NO3? leaves) or 40 millimolar KNO3 (high-NO3? leaves) nutrient solutions. PEPcase activity increased to 2.7-fold higher than that measured in dark-adapted tissue (control) during the first 60 minutes and continued to increase more slowly to 3.8-fold that of the control. This level was reached after 200 minutes exposure of the leaves to light and high NO3?. In contrast, the lower rate of increase recorded for low-NO3? leaves ceased after 60 minutes of exposure to light at 2.3-fold the control level. The short-term NO3? effect increased linearly with the level of NO3? uptake. In immunoprecipitation experiments, the antibody concentration for PEPcase precipitation increased with the protein extracts from the different treatments in the order: control, illuminated low-NO3? leaves, illuminated high-NO3? leaves. This order also applied with regard to a decreasing sensitivity to malate and an increasing stimulation by okadaic acid (an inhibitor of P-protein phosphatases). Following these studies, 32P labeling experiments were carried out in vivo. These showed that the light-induced change in the properties of the PEPcase was due to an alteration in the phosphorylation state of the protein and that this effect was enhanced in high-NO3? conditions. Based on the responses of PEPcase and sucrose phosphate synthase in wheat leaves to light and NO3?, an interpretation of the role of NO3? as either an inhibitor of P-protein phosphatase(s) or activator of protein kinase(s) is inferred. In the presence of NO3?, the phosphorylation state of both PEPcase and sucrose phosphate synthase is increased. This causes activation of the former enzyme and inhibition of the latter. We suggest that NO3? modulates the relative protein kinase/protein phosphatase ratio to favor increased phosphorylation of both enzymes in order to redirect carbon flow away from sucrose synthesis and toward amino acid synthesis. ImagesFigure 6 PMID:16668573

Le Van Quy; Foyer, Christine; Champigny, Marie-Louise

1991-01-01

359

Development of a Vsible-Light-Active Film for Direct Solar Energy Storage  

NASA Astrophysics Data System (ADS)

We conceived of a two-compartment photocatalytic assembly for direct storage of solar energy as chemical potential. Our approach was to maintain reductant and oxidant in separate compartments and develop a visible light (wavelength >400nm) photo-active film to effect an uphill photoreaction between compartments. A proton exchange membrane was included in the assembly to complete the electrical circuit. Towards obtaining a working prototype of the assembly, we developed a freeze-drying method to adhere visible-light photoactive nanoparticles to a self- standing, non-porous and conductive indium tin oxide-polyvinylidene difluoride (ITO-PVDF) support film, developed in-house. We explored the possibility of employing an iron-rich metal oxide as the photocatalytic component of the film and several were explored utilizing the sodium tartrate-assisted photoreduction of Cr(VI) to Cr(III). Although the Fe2O3-coated TiO2 nanoparticles were active for photoreduction, the initial reaction rate was modest and was slowed by substantial deactivation, making it unsuitable as a photo-active material for the composite film. A complete, two-compartment assembly was prepared using cadmium sulfide (CdS) and preliminarily examined for the Cr(VI) probe reaction, however, no catalytic activity was observed. To identify the reason(s) for this observation, further testing of the apparatus and the composite film is required.

Salazar, Audrey

360

Functional exchange of components between light-activated photoreceptor phosphodiesterase and hormone-activated adenylate cyclase systems  

SciTech Connect

Previous studies have noted profound similarities between the regulation of light-activated (3',5'-cyclic-nucleotide 5'-nucleotidohydrolase, EC 3.1.4.17) in retinal rods and hormone-activated adenylate cyclase (ATP pyrophosphate-lyase (cyclizing), EC 4.6.1.1) in a variety of tissues. We report ere the functional exchange of components isolated from the photoreceptor system, which displayed predicted functional characteristics when incubated with recipient adenylate cyclase systems from rat cerebral cortical and hypothalamic synaptic membranes and frog erythrocyte ghosts. We demonstrate functional exchange of photoreceptor components at each of three loci: the hormone receptor, the GTP-binding protein (GBP), and the catalytic moiety of adenylate cyclase. Illuminated (but not unilluminated) rhodopsin was found to mimic the hormone-receptor complex, causing GTP-dependent activation of adenylate cyclase. The photoreceptor GBP complexed with guanosine 5'-(..beta..,..gamma..)imidotriphosphate (p(NH)ppG) produced a marked activation of recipient adenylate cyclase systems. Much smaller activation was observed when GBP was not complexed with p(NH)ppG. A heat-stable photoreceptor phosphodiesterase inhibitor reduced both basal and Mn/sup 2 +/-activated adenylate cyclase activites and this inhibition was reversed by photoreceptor GBPp(NH)ppG. These data demonstrate a remarkable functional compatibility between subunits of both systems and furthermore imply that specialized peptide domains responsible for protein-protein interactions are highly conserved.

Bitensky, M.W.; Wheeler, M.A.; Rasenick, M.M.; Yamazaki, A.; Stein, P.J.; Halliday, K.R.; Wheeler, G.L.

1982-06-01

361

A comparison of the efficiency of G protein activation by ligand-free and light-activated forms of rhodopsin.  

PubMed Central

Activation of the photoreceptor G protein transducin (Gt) by opsin, the ligand-free form of rhodopsin, was measured using rod outer segment membranes with densities of opsin and Gt similar to those found in rod cells. When GTPgammaS was used as the activating nucleotide, opsin catalyzed transducin activation with an exponential time course with a rate constant k(act) on the order of 2 x 10(-3)s(-1). Comparison under these conditions to activation by flash-generated metarhodopsin II (MII) revealed that opsin- and R*-catalyzed activation showed similar kinetics when MII was present at a surface density approximately 10(-6) lower than that of opsin. Thus, in contrast to some previous reports, we find that the catalytic potency of opsin is only approximately 10(-6) that of MII. In the presence of residual retinaldehyde-derived species present in membranes treated with hydroxylamine after bleaching, the apparent k(act) observed was much higher than that for opsin, suggesting a possible explanation for previous reports of more efficient activation by opsin. These results are important for considering the possible role of opsin in the diverse phenomena in which it has been suggested to play a key role, such as bleaching desensitization and retinal degeneration induced by continuous light or vitamin A deprivation. PMID:9414230

Melia, T J; Cowan, C W; Angleson, J K; Wensel, T G

1997-01-01

362

Cryptochrome and phytochrome cooperatively but independently reduce active gibberellin content in rice seedlings under light irradiation.  

PubMed

In contrast to a wealth of knowledge about the photoregulation of gibberellin metabolism in dicots, that in monocots remains largely unclear. In this study, we found that a blue light signal triggers reduction of active gibberellin content in rice seedlings with simultaneous repression of two gibberellin 20-oxidase genes (OsGA20ox2 and OsGA20ox4) and acute induction of four gibberellin 2-oxidase genes (OsGA2ox4-OsGA2ox7). For further examination of the regulation of these genes, we established a series of cryptochrome-deficient lines through reverse genetic screening from a Tos17 mutant population and construction of knockdown lines based on an RNA interference technique. By using these lines and phytochrome mutants, we elucidated that cryptochrome 1 (cry1), consisting of two species in rice plants (cry1a and cry1b), is indispensable for robust induction of the GA2ox genes. On the other hand, repression of the GA20ox genes is mediated by phytochromes. In addition, we found that the phytochromes also mediate the repression of a gibberellin 3-oxidase gene (OsGA3ox2) in the light. These results imply that, in rice seedlings, phytochromes mediate the repression of gibberellin biosynthesis capacity, while cry1 mediates the induction of gibberellin inactivation capacity. The cry1 action was demonstrated to be dominant in the reduction of active gibberellin content, but, in rice seedlings, the cumulative effects of these independent actions reduced active gibberellin content in the light. This pathway design in which different types of photoreceptors independently but cooperatively regulate active gibberellin content is unique from the viewpoint of dicot research. This redundancy should provide robustness to the response in rice plants. PMID:22764280

Hirose, Fumiaki; Inagaki, Noritoshi; Hanada, Atsushi; Yamaguchi, Shinjiro; Kamiya, Yuji; Miyao, Akio; Hirochika, Hirohiko; Takano, Makoto

2012-09-01

363

Earthquake lights and the stress-activation of positive hole charge carriers in rocks  

USGS Publications Warehouse

Earthquake-related luminous phenomena (also known as earthquake lights) may arise from (1) the stress-activation of positive hole (p-hole) charge carriers in igneous rocks and (2) the accumulation of high charge carrier concentrations at asperities in the crust where the stress rates increase very rapidly as an earthquake approaches. It is proposed that, when a critical charge carrier concentration is reached, the p-holes form a degenerated solid state plasma that can break out of the confined rock volume and propagate as a rapidly expanding charge cloud. Upon reaching the surface the charge cloud causes dielectric breakdown at the air-rock interface, i.e. corona discharges, accompanied by the emission of light and high frequency electromagnetic radiation. ?? 2006 Elsevier Ltd. All rights reserved.

St-Laurent, F.; Derr, J.S.; Freund, F.T.

2006-01-01

364

An in vitro thermal analysis during different light-activated hydrogen peroxide bleaching  

NASA Astrophysics Data System (ADS)

This study measured the critical temperature reaching time and also the variation of temperature in the surface of the cervical region and within the pulp chamber of human teeth submitted to dental bleaching using 35% hydrogen peroxide gel activated by three different light sources. The samples were randomly divided into 3 groups ( n = 15), according to the catalyst light source: Halogen Light (HL), High Intensity Diode Laser (DL), and Light Emmited Diode (LED). The results of temperature variation were submitted to the analysis of variance and Tukey test with p < 0.05. The temperature increase (mean value and standard deviation) inside the pulp chamber for the HL group was 6.8 ± 2.8°C; for the DL group was 15.3 ± 8.8°C; and for the LED group was 1.9 ± 1.0°C for. The temperature variation (mean value and standard deviation) on the tooth surface, for the group irradiated with HL was 9.1 ± 2.2°C; for the group irradiated with DL were 25.7 ± 18.9°C; and for the group irradiated with LED were 2.6 ± 1.4°C. The mean temperature increase values were significantly higher for the group irradiated with DL when compared with groups irradiated with HL and LED ( p < 0.05). When applying the inferior limits of the interval of confidence of 95%, an application time of 38.7 s was found for HL group, and 4.4 s for DL group. The LED group did not achieve the critical temperatures for pulp or the periodontal, even when irradiated for 360 s. The HL and DL light sources may be used for dental bleaching for a short period of time. The LED source did not heat the target tissues significantly within the parameters used in this study.

Kabbach, W.; Zezell, D. M.; Bandéca, M. C.; Pereira, T. M.; Andrade, M. F.

2010-09-01

365

Tank Tests of Two Floats for High-speed Seaplanes  

NASA Technical Reports Server (NTRS)

At the request of the Bureau of Aeronautics, Navy Department, a study of the design of floats especially suitable for use on high-speed seaplanes was undertaken in the N.A.C.A. tank. This note give the results obtained in tests of one-quarter full-size models of two floats for high-speed seaplanes. One was a float similar to that used on the Macchi high-speed seaplane which competed in the 1926 Schneider Trophy races, and the other a float designed at the N.A.C.A. tank in an attempt to improve on the water performance of the Macchi float. The model of the latter showed considerably better water performance than the model of the Macchi float.

Bell, Joe W

1933-01-01

366

Direct observation of frequency modulated transcription in single cells using light activation  

PubMed Central

Single-cell analysis has revealed that transcription is dynamic and stochastic, but tools are lacking that can determine the mechanism operating at a single gene. Here we utilize single-molecule observations of RNA in fixed and living cells to develop a single-cell model of steroid-receptor mediated gene activation. We determine that steroids drive mRNA synthesis by frequency modulation of transcription. This digital behavior in single cells gives rise to the well-known analog dose response across the population. To test this model, we developed a light-activation technology to turn on a single steroid-responsive gene and follow dynamic synthesis of RNA from the activated locus. DOI: http://dx.doi.org/10.7554/eLife.00750.001 PMID:24069527

Larson, Daniel R; Fritzsch, Christoph; Sun, Liang; Meng, Xiuhau; Lawrence, David S; Singer, Robert H

2013-01-01

367

An Analysis of the Full-Floating Journal Bearing  

NASA Technical Reports Server (NTRS)

An analysis of the operating characteristics of a full-floating journal bearing, a bearing in which a floating sleeve is located between the journal and bearing surfaces, is presented together with charts from which the performance of such bearings may be predicted. Examples are presented to illustrate the use of these charts and a limited number of experiments conducted upon a glass full-floating bearing are reported to verify some results of the analysis.

Shaw, M C; Nussdorfer, T J , Jr

1947-01-01

368

Leaf life span of floating-leaved plants  

Microsoft Academic Search

Photosynthetic capacity of floating-leaved plants is relatively high comparable with terrestrial herbaceous plants, though floating-leaved plants have a much smaller biomass with a leaf area index seldom exceeding 2m2m-2. Their rather small biomass accumulation is related to higher turnover of leaf biomass or shorter leaf life span. Life span of floating leaves reported in the literature ranged mostly from 13

T. Tsuchiya

1991-01-01

369

A combined decimal and binary floating-point divider  

Microsoft Academic Search

In this paper, we present the hardware design of a combined decimal and binary floating-point divider, based on specifications in the IEEE 754-2008 Standard for Floating-point Arithmetic. In contrast to most recent decimal divider designs, which are based on the Binary Coded Decimal (BCD) encoding, our divider operates on either 64-bit binary encoded decimal floating-point (DFP) numbers or 64-bit binary

Sonia Gonzalez-Navarro; Alberto Nannarelli; Michael Schulte; Charles Tsen

2009-01-01

370

Activation of Phospholipase C Mimics the Phase Shifting Effects of Light on Melatonin Rhythms in Retinal Photoreceptors  

PubMed Central

Many aspects of retinal photoreceptor function and physiology are regulated by the circadian clocks in these cells. It is well established that light is the primary stimulus that entrains these clocks; yet, the biochemical cascade(s) mediating light’s effects on these clocks remains unknown. This deficiency represents a significant gap in our fundamental understanding of photoreceptor signaling cascades and their functions. In this study, we utilized re-aggregated spheroid cultures prepared from embryonic chick retina to determine if activation of phospholipase C in photoreceptors in the absence of light can phase shift the melatonin secretion rhythms of these cells in a manner similar to that induced by light. We show that spheroid cultures rhythmically secrete melatonin and that these melatonin rhythms can be dynamically phase shifted by exposing the cultures to an appropriately timed light pulse. Importantly, we show that activation of phospholipase C using m-3M3FBS in the absence of light induces a phase delay in photoreceptor melatonin rhythms that mirrors that induced by light. The implication of this finding is that the light signaling cascade that entrains photoreceptor melatonin rhythms involves activation of phospholipase C. PMID:24386190

Semple-Rowland, Susan; Madorsky, Irina; Bolch, Susan; Berry, Jonathan; Smith, W. Clay

2013-01-01

371

Nonmetal species in the carbon modified TiO2 and its visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

A carbon modified TiO2 (CT) was synthesized by hydrolyzing titanium tetrachloride with diethylamine and calcination at 400 °C. CT was then handled with a NaOH aqueous solution elution and a subsequent re-assembling treatment. X-ray diffraction (XRD), transmission electron microscopy (TEM), nitrogen adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), thermogravimetric and differential thermal analysis (TG-DTA), chemical oxygen demand (COD) and UV-vis diffuse reflectance spectroscopy (DRS) were then used to assess the changes of CT during the whole process. It is revealed that carbon in the CT should mostly be presented as surface deposited organic matters but not likely doped into the TiO2 lattice. CT exhibits obvious visible absorption and high photocatalytic activity for the degradation of 2,4-dichlorophenol (DCP) under visible light irradiation. Meanwhile, CT photocatalyst possesses excellent stability and reusability. NaOH solution elution washes off a large amount of surface deposited organics and worsens the visible absorbance and photocatalytic activity of CT, which can be well recovered by the re-assembling treatment. The re-assembled photocatalyst, CTSL, exhibits exhibits a very similar photocataytic activity with CT for degradation of DCP under the visible light irradiation, but is much higher than that of CTS.

Shi, Yanfen; Chen, Feng; Zhang, Jinlong

2013-01-01

372

A coronagraph based on two spatial light modulators for active amplitude apodizing and phase corrections  

NASA Astrophysics Data System (ADS)

Almost all high-contrast imaging coronagraphs proposed until now are based on passive coronagraph optical components. Recently, Ren and Zhu proposed for the first time a coronagraph that integrates a liquid crystal array (LCA) for the active pupil apodizing and a deformable mirror (DM) for the phase corrections. Here, for demonstration purpose, we present the initial test result of a coronagraphic system that is based on two liquid crystal spatial light modulators (SLM). In the system, one SLM is served as active pupil apodizing and amplitude correction to suppress the diffraction light; another SLM is used to correct the speckle noise that is caused by the wave-front distortions. In this way, both amplitude and phase error can be actively and efficiently compensated. In the test, we use the stochastic parallel gradient descent (SPGD) algorithm to control two SLMs, which is based on the point spread function (PSF) sensing and evaluation and optimized for a maximum contrast in the discovery area. Finally, it has demonstrated a contrast of 10-6 at an inner working angular distance of ~6.2 ?/D, which is a promising technique to be used for the direct imaging of young exoplanets on ground-based telescopes.

Dou, Jiangpei; Ren, Deqing; Zhang, Xi; Zhu, Yongtian; Zhao, Gang; Wu, Zhen; Chen, Rui; Liu, Chengchao; Yang, Feng; Yang, Chao

2014-08-01

373

Visible Light Active Cu2+/TiO2 Nanocatalyst for Degradation of Dichlorvos  

NASA Astrophysics Data System (ADS)

The advantage of doping of TiO2 with copper has been utilized for enhanced degradation of pesticide under visible light irradiation. The sol-gel method has been undertaken for the synthesis of copper-doped TiO2 by varying the dopant loadings from 0.25 wt.% to 1.0 wt.% of Cu2+. The doped samples were characterized by UV-Visible Diffuse Reflectance Spectroscopy (DRS), N2 adsorption-desorption (BET), X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectrometry (EDS). The photocatalytic activity of the catalyst was tested by degradation of dichlorvos under visible light illumination. The results found that 0.75 wt.% of Cu2+ doped nanocatalysts have better photo catalytic activity than the rest of percentages doped, undoped TiO2 and Degussa P25. The reduction of band gap was estimated and the influence of the process parameters on photo catalytic activity of the catalyst has been explained.

Segne, Teshome Abdo; Tirukkovalluri, Siva Rao; Challapalli, Subrahmanyam

2012-10-01

374

Visible light photocatalytic activity of BiVO4 particles with different morphologies  

NASA Astrophysics Data System (ADS)

Bismuth vanadate (BiVO4) particles with different morphologies were synthesized by a one-step hydrothermal process and their optical and photocatalytic properties were investigated. Their crystal structure and microstructures were characterized using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). XRD patterns demonstrate that the as-prepared samples are monoclinic cell. FESEM shows that BiVO4 crystals can be fabricated in different morphologies by simply manipulating the reaction parameters of hydrothermal process. The UV-visible diffuse reflectance spectra (UV-vis DRS) reveal that the band gaps of BiVO4 photocatalysts are about 2.07-2.21 eV. The as-prepared BiVO4 photocatalysts exhibit higher photocatalytic activities in the degradation of rhodamine B (Rh B) under visible light irradiation (? > 420 nm) compared with traditional N-doped TiO2 (N-TiO2). Furthermore, wheat like BiVO4 sample reveals the highest photocatalytic activity. Up to 100% Rh B is decolorized after visible light irradiation for 180 min. The reason for the difference in the photocatalytic activities for BiVO4 samples obtained at different conditions were systematically studied based on their shape, size and the variation of local structure.

Lin, Xue; Yu, Lili; Yan, Lina; Li, Hongji; Yan, Yongsheng; Liu, Chunbo; Zhai, Hongju

2014-06-01

375

Monolithic crystalline cladding microstructures for efficient light guiding and beam manipulation in passive and active regimes  

PubMed Central

Miniature laser sources with on-demand beam features are desirable devices for a broad range of photonic applications. Lasing based on direct-pump of miniaturized waveguiding active structures offers a low-cost but intriguing solution for compact light-emitting devices. In this work, we demonstrate a novel family of three dimensional (3D) photonic microstructures monolithically integrated in a Nd:YAG laser crystal wafer. They are produced by the femtosecond laser writing, capable of simultaneous light waveguiding and beam manipulation. In these guiding systems, tailoring of laser modes by both passive/active beam splitting and ring-shaped transformation are achieved by an appropriate design of refractive index patterns. Integration of graphene thin-layer as saturable absorber in the 3D laser structures allows for efficient passive Q-switching of tailored laser radiations which may enable miniature waveguiding lasers for broader applications. Our results pave a way to construct complex integrated passive and active laser circuits in dielectric crystals by using femtosecond laser written monolithic photonic chips. PMID:25100561

Jia, Yuechen; Cheng, Chen; Vazquez de Aldana, Javier R.; Castillo, Gabriel R.; Rabes, Blanca del Rosal; Tan, Yang; Jaque, Daniel; Chen, Feng

2014-01-01

376

Floating Drug Delivery of Nevirapine as a Gastroretentive System  

PubMed Central

A multiple-unit floating drug delivery system based on gas formation technique was developed, in order to prolong the gastric residence time and to increase the overall bioavailability of the dosage form. The floating bead formulations were prepared by dispersing nevirapine together with calcium carbonate in a mixture of sodium alginate and hydroxypropyl methylcellulose solution and then dripping the dispersion into an acidified solution of calcium chloride. Calcium alginate beads were formed, as the alginate underwent ionotropic gelation by calcium ions, and carbon dioxide developed from the reaction of carbonate salts with acid. The obtained beads were able to float due to CO2-gas formation and the gas entrapment by the polymeric membrane. The prepared beads were evaluated for percent drug loading, drug entrapment efficiency, morphology, surface topography, buoyancy, in-vitro release, and release kinetics. The formulations were optimized for different weight ratios of the gas-forming agent and sodium alginate. The beads containing higher amounts of calcium carbonate demonstrated an instantaneous, complete, and excellent floating ability over a period of 24 hours. The increased amount of the gas forming agent did not affect the time to float, but increased the drug release from the floating beads, while increasing the coating level of the gas-entrapped membrane, increased the time to float, and slightly retarded the drug release. Good floating properties and sustained drug release were achieved. Finally, these floating beads seemed to be a promising gastroretentive drug delivery system. PMID:21264092

Vedha, Hari BN; Brahma, Reddy A; Samyuktha, Rani B

2010-01-01

377

Activity of interferon on ultraviolet light-induced squamous cell carcinomas in mice  

SciTech Connect

The activity of interferons was tested in ultraviolet light-induced skin tumors in mice. After the tumors were well established, they were injected and measured daily for 19 days. Mouse virus type (IF-alpha + IF-beta) and immune (IF-gamma) interferons were injected intralesionally into three groups of test animals and compared with a fourth group which received mock interferon (control). When used separately, virus type and immune interferons did not affect tumor growth; however, we observed regression in tumor size when the two interferons were used in combination.

Brysk, M.M.; Tschen, E.H.; Hudson, R.D.; Smith, E.B.; Fleischmann, W.R. Jr.; Black, H.S.

1981-07-01

378

Graphene-based electrically reconfigurable deep-subwavelength metamaterials for active control of THz light propagation  

NASA Astrophysics Data System (ADS)

This work studies the terahertz light propagation through graphene-based reconfigurable metasurfaces where the unit cell dimensions are much smaller than the terahertz wavelength. The proposed devices, which poses deep-subwavelength unit cell and active region dimensions can operate as amplitude and/or phase modulators in certain specific frequency bands determined by the device geometry. Reconfigurability is attained via electrostatically tuning the optical conductivity of patterned graphene layers, which are strategically located in each unit cell. The ultra-small unit cell dimensions can be advantageous for beam shaping applications.

Arezoomandan, Sara; Yang, Kai; Sensale-Rodriguez, Berardi

2014-08-01

379

Two-photon single-cell optogenetic control of neuronal activity by sculpted light.  

PubMed

Recent advances in optogenetic techniques have generated new tools for controlling neuronal activity, with a wide range of neuroscience applications. The most commonly used approach has been the optical activation of the light-gated ion channel channelrhodopsin-2 (ChR2). However, targeted single-cell-level optogenetic activation with temporal precessions comparable to the spike timing remained challenging. Here we report fast (< or = 1 ms), selective, and targeted control of neuronal activity with single-cell resolution in hippocampal slices. Using temporally focused laser pulses (TEFO) for which the axial beam profile can be controlled independently of its lateral distribution, large numbers of channels on individual neurons can be excited simultaneously, leading to strong (up to 15 mV) and fast (< or = 1 ms) depolarizations. Furthermore, we demonstrated selective activation of cellular compartments, such as dendrites and large presynaptic terminals, at depths up to 150 microm. The demonstrated spatiotemporal resolution and the selectivity provided by TEFO allow manipulation of neuronal activity, with a large number of applications in studies of neuronal microcircuit function in vitro and in vivo. PMID:20543137

Andrasfalvy, Bertalan K; Zemelman, Boris V; Tang, Jianyong; Vaziri, Alipasha

2010-06-29

380

Upper Limb Muscle and Brain Activity in Light Assembly Task on Different Load Levels  

NASA Astrophysics Data System (ADS)

A study was conducted to investigate the effect of load on upper limb muscles and brain activities in light assembly task. The task was conducted at two levels of load (Low and high). Surface electromyography (EMG) was used to measure upper limb muscle activities of twenty subjects. Electroencephalography (EEG) was simultaneously recorded with EMG to record brain activities from Fz, Pz, O1 and O2 channels. The EMG Mean Power Frequency (MPF) of the right brachioradialis and the left upper trapezius activities were higher on the high-load task compared to low-load task. The EMG MPF values also decrease as time increases, that reflects muscle fatigue. Mean power of the EEG alpha bands for the Fz-Pz channels were found to be higher on the high-load task compared to low-load task, while for the O1-O2 channels, they were higher on the low-load task than on the high-load task. These results indicated that the load levels effect the upper limb muscle and brain activities. The high-load task will increase muscle activities on the right brachioradialis and the left upper tapezius muscles, and will increase the awareness and motivation of the subjects. Whilst the low-load task can generate drowsiness earlier. It signified that the longer the time and the more heavy of the task, the subjects will be more fatigue physically and mentally.

Zadry, Hilma Raimona; Dawal, Siti Zawiah Md.; Taha, Zahari

2010-10-01

381

Accurately resolving PIC and POC from autonomous floats  

NASA Astrophysics Data System (ADS)

Real-time measurement of particulate inorganic carbon (PIC) and particulate organic carbon (POC) is essential to improve our spatial and temporal understanding of carbon flux in the world's oceans and the effects of ocean acidification on the biological pump. Beam transmission can be used to detect the concentration of both PIC and POC. Birefringence of calcium carbonate (CaCO3) is widely used as a method to identify PIC. A modified WET Labs C-star beam transmissometer was developed to measure the concentration of suspended CaCO3 minerals in the optical path of polarized light from a laser source while birefringent light which is partially depolarized is detected at the other end (25-cm path length). Work is focused on the design of neutrally buoyant PIC and POC sensors for deployment on the Carbon Explorers (CE) autonomous floats, and optimization of the optical design for accurately resolving PIC. Results from the evaluation of polarizer mounting methods from the laboratory and recent water-column PIC measurements collected in the field are presented.

Orrico, C.; Bishop, J. K.; Weiss, G.; Wood, T. J.; Strubhar, W.; Derr, A.; Barnard, A. H.; Moore, C.

2012-12-01

382

Phosphoenolpyruvate Carboxylase Kinase in Tobacco Leaves Is Activated by Light in a Similar but Not Identical Way as in Maize.  

PubMed Central

We have previously reported the partial purification of a Ca2+- independent phosphoenolpyruvate carboxylase (PEPC) protein-serine/threonine kinase (PEPC-PK) from illuminated leaves of N-sufficient tobacco (Nicotiana tabacum L.) plants (Y.-H. Wang, R. Chollet [1993] FEBS Lett 328: 215-218). We now report that this C3 PEPC-kinase is reversibly light activated in vivo in a time-dependent manner. As the kinase becomes light activated, the activity and L-malate sensitivity of its target protein increases and decreases, respectively. The light activation of tobacco PEPC-PK is prevented by pretreatment of detached leaves with various photosynthesis and cytosolic protein-synthesis inhibitors. Similarly, specific inhibitors of glutamine synthetase block the light activation of tobacco leaf PEPC-kinase under both photorespiratory and nonphotorespiratory conditions. This striking effect is partially and specifically reversed by exogenous glutamine, whereas it has no apparent effect on the light activation of the maize (Zea mays L.) leaf kinase. Using an in situ "activity-gel" phosphorylation assay, we have identified two major Ca2+-independent PEPC-kinase catalytic polypeptides in illuminated tobacco leaves that have the same molecular masses (approximately 30 and 37 kD) as found in illuminated maize leaves. Collectively, these results indicate that the phosphorylation of PEPC in N-sufficient leaves of tobacco (C3) and maize (C4) is regulated through similar but not identical light-signal transduction pathways. PMID:12226305

Li, B.; Zhang, X. Q.; Chollet, R.

1996-01-01

383

Apparent Absence of a Redox Requirement for Blue Light Activation of Pump Current in Broad Bean Guard Cells1  

E-print Network

-activated currents are voltage independent over a wide range of membrane potentials. During BL-activated responses, membrane hyperpolarization in response to a blue light (BL) stimulus is achieved by the activation of a plasma membrane H -ATPase. Using the patch clamp technique on broad bean (Vicia faba) guard cells we

Taylor, Alison

384

The impact of floating migration on fertility in China: are floating migrants "childbearing guerillas"?  

E-print Network

of the country on the fertility/migration issue. A three-step analysis containing a series of Poisson regression models is conducted and existing migration/fertility theories are used to explain the results of the analysis. Floating migrants are defined as those...

You, Xiuhong

2012-06-07

385

Floating production unit to work off Brazil  

SciTech Connect

This paper reports that Petroleo Brasileiro SA expects by early November to deploy its Petrobras XXIV floating production unit (FPU) in about 900 ft of water in Albacora field off Brazil. The FPU was scheduled to depart Galveston, Tex., this month, following completion of modifications and upgrades under a turnkey contract with Chiles Offshore International Inc. Chiles began modifying Petrobras XXIV about 1 year ago as part of a deal closed in October 1991 in which Chiles Offshore Corp. sold the vessel, then known as Intrepid, to Brasoil, the international subsidiary of Petrobras.

Not Available

1992-10-19

386

Graphene nano-floating gate transistor memory on plastic.  

PubMed

A transparent flexible graphene nano-floating gate transistor memory (NFGTM) device was developed by combining a single-layer graphene active channel with gold nanoparticle (AuNP) charge trap elements. We systematically controlled the sizes of the AuNPs, the thickness of the tunneling dielectric layer, and the graphene doping level. In particular, we propose that the conductance difference (i.e., memory window) between the programming and erasing operations at a specific read gate voltage can be maximized through the doping. The resulting graphene NFGTMs developed here exhibited excellent programmable memory performances compared to previously reported graphene memory devices and displayed a large memory window (12 V), fast switching speed (1 ?s), robust electrical reliability (10(5) s), and good mechanical (500 cycles) and thermal stability (100 °C). PMID:25382657

Jang, Sukjae; Hwang, Euyheon; Cho, Jeong Ho

2014-12-21

387

Light effects on ?-amylase activity and carbohydrate content in relation to lipid mobilization during the seedling growth of sunflower  

Microsoft Academic Search

The changes in ?-amylase activity and in starch and free sugar content were investigated in correlation with lipid mobilization\\u000a inHelianthus annuus during the first 15 days of seedling growth in discontinuous light and in darkness. Throughout the seedling development ?-amylase\\u000a activity increased more significantly in light than in darkness. It was always lower in cotyledons than in other tissues of

Nicole Darbelley; Njara Razafindramboa; Jean-Pierre Chambost; Andr'e Pavia

1997-01-01

388

Solution-Processed Nanoparticle Super-Float-Gated Organic Field-Effect Transistor as Un-cooled Ultraviolet and Infrared Photon Counter  

PubMed Central

High sensitivity photodetectors in ultraviolet (UV) and infrared (IR) range have broad civilian and military applications. Here we report on an un-cooled solution-processed UV-IR photon counter based on modified organic field-effect transistors. This type of UV detectors have light absorbing zinc oxide nanoparticles (NPs) sandwiched between two gate dielectric layers as a floating gate. The photon-generated charges on the floating gate cause high resistance regions in the transistor channel and tune the source-drain output current. This “super-float-gating” mechanism enables very high sensitivity photodetectors with a minimum detectable ultraviolet light intensity of 2.6?photons/?m2s at room temperature as well as photon counting capability. Based on same mechansim, infrared photodetectors with lead sulfide NPs as light absorbing materials have also been demonstrated. PMID:24048259

Yuan, Yongbo; Dong, Qingfeng; Yang, Bin; Guo, Fawen; Zhang, Qi; Han, Ming; Huang, Jinsong

2013-01-01

389

Controlling an actively-quenched single photon detector with bright light  

E-print Network

We control using bright light an actively-quenched avalanche single-photon detector. Actively-quenched detectors are commonly used for quantum key distribution (QKD) in the visible and near-infrared range. This study shows that these detectors are controllable by the same attack used to hack passively-quenched and gated detectors. This demonstrates the generality of our attack and its possible applicability to eavsdropping the full secret key of all QKD systems using avalanche photodiodes (APDs). Moreover, the commercial detector model we tested (PerkinElmer SPCM-AQR) exhibits two new blinding mechanisms in addition to the previously observed thermal blinding of the APD, namely: malfunctioning of the bias voltage control circuit, and overload of the DC/DC converter biasing the APD. These two new technical loopholes found just in one detector model suggest that this problem must be solved in general, by incorporating generally imperfect detectors into the security proof for QKD.

Sebastien Sauge; Lars Lydersen; Andrey Anisimov; Johannes Skaar; Vadim Makarov

2008-09-19

390

Floating microspheres bearing acetohydroxamic acid for the treatment of Helicobacter pylori.  

PubMed

This investigation is part of our ongoing effort to develop effective drug delivery systems for the treatment of Helicobacter pylori infection using polycarbonate (PC) floating microspheres as drug carriers. In an effort to augment the anti-H. pylori effect of acetohydroxamic acid (AHA), floating PC microspheres, which have the ability to reside in the gastrointestinal (GI) tract for an extended period, were prepared by emulsion (O/W) solvent evaporation technique. The effect of PC concentration on the morphology, particle size, entrapment efficiency and drug release rate was studied. In-vitro studies confirmed the excellent floating properties of PC microspheres. In-vitro and in-vivo growth inhibition studies were performed on developed system(s) taking isolated cultures of H. pylori and H. pylori-infected Mongolian gerbils, respectively. The drug and PC microspheres both showed anti-H. pylori activity in vivo, but the required dose of AHA was effectively reduced by a factor of 10 in the case of PC microspheres. In conclusion, the floating microspheres more effectively cleared H. pylori from the GI tract than the drug because of the prolonged gastric residence time resulting from the excellent buoyancy of the PC. PMID:14738585

Umamaheshwari, R B; Jain, Subheet; Bhadra, Dipankar; Jain, N K

2003-12-01

391

A toolbox of Cre-dependent optogenetic transgenic mice for light-induced activation and silencing.  

PubMed

Cell type-specific expression of optogenetic molecules allows temporally precise manipulation of targeted neuronal activity. Here we present a toolbox of four knock-in mouse lines engineered for strong, Cre-dependent expression of channelrhodopsins ChR2-tdTomato and ChR2-EYFP, halorhodopsin eNpHR3.0 and archaerhodopsin Arch-ER2. All four transgenes mediated Cre-dependent, robust activation or silencing of cortical pyramidal neurons in vitro and in vivo upon light stimulation, with ChR2-EYFP and Arch-ER2 demonstrating light sensitivity approaching that of in utero or virally transduced neurons. We further show specific photoactivation of parvalbumin-positive interneurons in behaving ChR2-EYFP reporter mice. The robust, consistent and inducible nature of our ChR2 mice represents a significant advance over previous lines, and the Arch-ER2 and eNpHR3.0 mice are to our knowledge the first demonstration of successful conditional transgenic optogenetic silencing. When combined with the hundreds of available Cre driver lines, this optimized toolbox of reporter mice will enable widespread investigations of neural circuit function with unprecedented reliability and accuracy. PMID:22446880

Madisen, Linda; Mao, Tianyi; Koch, Henner; Zhuo, Jia-min; Berenyi, Antal; Fujisawa, Shigeyoshi; Hsu, Yun-Wei A; Garcia, Alfredo J; Gu, Xuan; Zanella, Sebastien; Kidney, Jolene; Gu, Hong; Mao, Yimei; Hooks, Bryan M; Boyden, Edward S; Buzsáki, György; Ramirez, Jan Marino; Jones, Allan R; Svoboda, Karel; Han, Xue; Turner, Eric E; Zeng, Hongkui

2012-05-01

392

A System for Implanting Laboratory Mice with Light-Activated Microtransponders  

PubMed Central

The mouse is the most commonly used laboratory animal, accounting for up to 80% of all mammals used in research studies. Because rodents generally are group-housed, an efficient system of uniquely identifying individual animals for use in research studies, breeding, and proper colony management is required. Several temporary and permanent methods (for example, ear punching and toe clipping) are available for labeling research mice and other small animals, each with advantages and disadvantages. This report describes a new radiofrequency identification tagging method that uses 500-µm, light-activated microtransponders implanted subcutaneously into the ear or tail of mice. The preferred location for implanting is in the side of the tail, because implantation at this site was simple to perform and was associated with shorter implantation times (average, 53 versus 325 s) and a higher success rate (98% versus 50%) compared with the ear. The main benefits of using light-activated microtransponders over other identification methods, including other radiofrequency identification tags, is their small size, which minimizes stress to the animals during implantation and low cost due to their one-piece (monolithic) design. In addition, the implantation procedure uses a custom-designed 21-gauge needle injector and does not require anesthetization of the mice. We conclude that this method allows improved identification and management of laboratory mice. PMID:21205448

Gruda, Maryann C; Pinto, Amanda; Craelius, Aaron; Davidowitz, Hanan; Kopacka, Wesley M; Li, Ji; Qian, Jay; Rodriguez, Efrain; Kuspiel, Edward; Mandecki, Wlodek

2010-01-01

393

Reflection of light: a teaching and learning activity with primary school children  

NASA Astrophysics Data System (ADS)

Light and its properties is a subject that strongly attracts children from very early ages. Inquiry-based science teaching although addressed in the curricula of various countries and suggested by some international organizations, continues to have a very low expression in the teaching practices of the majority of primary school teachers and preschool educators. In this sense, we have organized several continuing training courses in order to encourage these education professionals to promote this approach to science teaching in the classroom, with the children. As part of this training process, teachers and educators put into practice, with their students, the didactic knowledge they have developed, in order to become aware of the virtues of an inquiry-based approach to children's learning. Through the implementation of the "Reflection of Light" activity, in this article, we intend to analyze the process of teaching and learning promoted in a 3rd grade class by one of the teachers participating in the training courses. The analysis of the process reveals that the teacher in training carried out a successful didactic integration of the inquiry-based science teaching approach recommended for children. In turn, the children also developed a good understanding of the contents of the activity explored in the classroom.

Varela, Paulo; Abreu, Cátia; Costa, Manuel F. M.

2014-08-01

394

Dark/Light modulation of ribulose bisphosphate carboxylase activity in plants from different photosynthetic categories.  

PubMed

Ribulose bisphosphate carboxylase/oxygenase (RuBPCase) from several plants had substantially greater activity in extracts from lightexposed leaves than dark leaves, even when the extracts were incubated in vitro with saturating HCO(3) (-) and Mg(2+) concentrations. This occurred in Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Panicum bisulcatum, and P. hylaeicum (C(3)); P. maximum (C(4) phosphoenolpyruvate carboxykinase); P. milioides (C(3)/C(4)); and Bromelia pinguin and Ananas comosus (Crassulacean acid metabolism). Little or no difference between light and dark leaf extracts of RuBPCase was observed in Triticum aestivum (C(3)); P. miliaceum (C(4) NAD malic enzyme); Zea mays and Sorghum bicolor (C(4) NADP malic enzyme); Moricandia arvensis (C(3)/C(4)); and Hydrilla verticillata (submersed aquatic macrophyte). It is concluded that, in many plants, especially Crassulacean acid metabolism and C(3) species, a large fraction of ribulose-1,5-bisphosphate carboxylase/oxygenase in the dark is in an inactivatable state that cannot respond to CO(2) and Mg(2+) activation, but which can be converted to an activatable state upon exposure of the leaf to light. PMID:16663937

Vu, J C; Allen, L H; Bowes, G

1984-11-01

395

Dark/Light Modulation of Ribulose Bisphosphate Carboxylase Activity in Plants from Different Photosynthetic Categories 1  

PubMed Central

Ribulose bisphosphate carboxylase/oxygenase (RuBPCase) from several plants had substantially greater activity in extracts from lightexposed leaves than dark leaves, even when the extracts were incubated in vitro with saturating HCO3? and Mg2+ concentrations. This occurred in Glycine max, Lycopersicon esculentum, Nicotiana tabacum, Panicum bisulcatum, and P. hylaeicum (C3); P. maximum (C4 phosphoenolpyruvate carboxykinase); P. milioides (C3/C4); and Bromelia pinguin and Ananas comosus (Crassulacean acid metabolism). Little or no difference between light and dark leaf extracts of RuBPCase was observed in Triticum aestivum (C3); P. miliaceum (C4 NAD malic enzyme); Zea mays and Sorghum bicolor (C4 NADP malic enzyme); Moricandia arvensis (C3/C4); and Hydrilla verticillata (submersed aquatic macrophyte). It is concluded that, in many plants, especially Crassulacean acid metabolism and C3 species, a large fraction of ribulose-1,5-bisphosphate carboxylase/oxygenase in the dark is in an inactivatable state that cannot respond to CO2 and Mg2+ activation, but which can be converted to an activatable state upon exposure of the leaf to light. PMID:16663937

Vu, J. Cu V.; Allen, Leon H.; Bowes, George

1984-01-01

396

Locomotor activity in common spiny mice (Acomys cahirinuse): The effect of light and environmental complexity  

PubMed Central

Background Rodents typically avoid illuminated and open areas, favoring dark or sheltered environments for activity. While previous studies focused on the effect of these environmental attributes on the level of activity, the present study tested whether the spatio-temporal structure of activity was also modified in illuminated compared with dark and complex compared with open arenas. For this, we tested common spiny mice (Acomys cahirinus) in empty or stone-containing arenas with lights on or lights off. Results In an illuminated or open arena, spiny mice moved in less frequent but longer trips with relatively long distances between consecutive stops. In contrast, in either a dark arena or an arena with stones, the animals took shorter and more frequent trips, with more stops per trip and shorter inter-stop distances. In illuminated arenas spiny mice remained mainly along the walls, whereas locomotion in the center was more prevalent in dark empty arenas, and was carried out along convoluted paths. Increasing environmental complexity by adding stones to either illuminated or dark arenas increased locomotion along straight trajectories and away from walls. Conclusions Earlier findings of reduced activity in illuminated or open areas have been extended in the present study by demonstrating changes in the spatio-temporal structure of locomotor behavior. In the more complex arenas (with stones) spiny mice traveled along short straight segments whereas in the open their trips were longer and took the shape of a zigzag path which is more effective against fast or nearby predators. Alternatively, the zigzag path may reflect a difficulty in navigation. PMID:15537426

Eilam, David

2004-01-01

397

Free floating planets in stellar clusters?  

E-print Network

We have simulated encounters between planetary systems and single stars in various clustered environments. This allows us to estimate the fraction of systems liberated, the velocity distribution of the liberated planets, and the separation and eccentricity distributions of the surviving bound systems. Our results indicate that, for an initial distribution of orbits that is flat in log space and extends out to 50AU, 50% of the available planets can be liberated in a globular cluster, 25% in an open cluster, and less than 10% in a young cluster. These fractions are reduced to 25%, 12% and 2% if the initial population extends only to 20AU. Furthermore, these free-floating planets can be retained for longer than a crossing time only in a massive globular cluster. It is therefore difficult to see how planets, which by definition form in a disc around a young star, could be subsequently liberated to form a significant population of free floating substellar objects in a cluster.

Kester W. Smith; Ian A. Bonnell

2001-01-05

398

Suppression of Marangoni Convection in Float Zones  

NASA Technical Reports Server (NTRS)

The basic purpose of this program is to demonstrate by means of an Earth-based 1-g experiment that the undesirable Marangoni (surface tension) convection can be suppressed or significantly reduced by means of gas jets directed tangentially to the free surface of the liquid in a float zone. These jets will establish the tangential shear stress field over the surface which must be adjusted to equal the counter-stress resultant of the Marangoni shear stress which causes the convection. For proposed materials processing in space (o-g), particularly of important, highly reactive semiconductor materials, e.g., silicon, microgravity will virtually eliminate the unwanted thermal-buoyancy convection in the liquid silicon, but will have no effect in reducing the Marangoni convection. Unless this can be sufficiently suppressed by other means, there may be no significant advantages to the proposed space processing of reactive semiconductors. Although some inert gas such as argon must be used for the corrosive liquid silicon, the Earth-based experiment uses air jets and various transparent oils, since the basic principle involved is the same. The first float zone is enclosed in a very small rectangular box with a quasi-planar free surface. Stable Marangoni convection has been achieved and velocities measured photographically. The air jet system with variable velocity and temperature is under construction. Three independent parameters must be optimized to attain maximum suppression: the gas velocity, angle of attack, and gas temperature.

Dressler, R. F.

1985-01-01

399

Water-Pressure Distribution on Seaplane Float  

NASA Technical Reports Server (NTRS)

The investigation presented in this report was conducted for the purpose of determining the distribution and magnitude of water pressures likely to be experienced on seaplane hulls in service. It consisted of the development and construction of apparatus for recording water pressures lasting one one-hundredth second or longer and of flight tests to determine the water pressures on a UO-1 seaplane float under various conditions of taxiing, taking off, and landing. The apparatus developed was found to operate with satisfactory accuracy and is suitable for flight tests on other seaplanes. The tests on the UO-1 showed that maximum pressures of about 6.5 pounds per square inch occur at the step for the full width of the float bottom. Proceeding forward from the step the maximum pressures decrease in magnitude uniformly toward the bow, and the region of highest pressures narrows toward the keel. Immediately abaft the step the maximum pressures are very small, but increase in magnitude toward the stern and there once reached a value of about 5 pounds per square inch. (author)

Thompson, F L

1929-01-01

400

Light-activated plant growth inhibitory activity of cis-dehydromatricaria ester, rose bengal and fluoren-9-one on lettuce ( Lactuca saliva L.)  

Microsoft Academic Search

The polyacetylene allelopathic compound cis-dehydromatricaria ester (cis-DME) was extracted from the roots of goldenrod, Solidago altissima L. cis-DME strongly inhibited the growth of lettuce (Lactuca saliva L. c. v. sacramento) on its radicles and hypocotyls in the presence of light whereas less or no significantly different effects were observed in the dark. The light-activated plant growth inhibitory (PGI) activity of

Rong Tsao; Morifusa Eto

1996-01-01

401

Full-wave analysis of microstrip floating-line discontinuities  

Microsoft Academic Search

A full-wave analysis of the resonance generated by a floating line is presented. Beginning with the dyadic Green's function for a dielectric slab, an integral equation is formulated. This integral equation is then solved by the method of moments in obtaining the transmission and reflection coefficients, as well as current distributions along the transmission line and on the floating line,

Guang-Wen Pan; Jilin Tan; J. D. Murphy

1994-01-01

402

Nitrogen uptake by the floating macrophyte Lemna minor  

Microsoft Academic Search

Summary • Both roots and leaves of free-floating plants can potentially take up nutrients. In this study, the ability and relative contribution of roots and fronds for N uptake by the floating macrophyte Lemna minor was investigated. • The NH4+ and NO3- uptake kinetics of roots and fronds were measured on plants acclimated to three different NH4 NO3 concentrations. •

Nina Cedergreen; Tom Vindbaek Madsen

2002-01-01

403

Coupled dynamic analysis of floating offshore wind farms  

E-print Network

................................................................................... 52 3.2.3 Wind speed 11m/s case................................................................................. 63 3.3 Coupling simulation for the modified floating wind turbine in the time domain... and uncoupled case in wind speed 5m/s ...........................................................52 Figure 3-44 External force time series and spectra on the floating body of the uncoupled case in wind speed 8m...

Shim, Sangyun

2009-05-15

404

40 CFR 65.44 - External floating roof (EFR).  

...floating roof (EFR). (a) EFR design requirements. The owner...floating roof shall comply with the design requirements listed in paragraphs...seal shall be either a metallic shoe seal or a liquid-mounted seal...liquid-mounted or metallic shoe primary seal as of...

2014-07-01

405

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2012 CFR

...floating roof (EFR). (a) EFR design requirements. The owner...floating roof shall comply with the design requirements listed in paragraphs...seal shall be either a metallic shoe seal or a liquid-mounted seal...liquid-mounted or metallic shoe primary seal as of...

2012-07-01

406

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2013 CFR

...floating roof (EFR). (a) EFR design requirements. The owner...floating roof shall comply with the design requirements listed in paragraphs...seal shall be either a metallic shoe seal or a liquid-mounted seal...liquid-mounted or metallic shoe primary seal as of...

2013-07-01

407

Argo at PMEL: Intro http://floats.pmel.noaa.gov  

E-print Network

) �End-to-end (Float providers involved in instrumentation development, preparation & testing, deployment at PMEL: Float Preparation �Suite of tests developed with academic colleagues & manufacturers and data quality -Inspect exterior, seals, &components -Check weight -Test transmitter, oil pump, vacuum

408

Reduction of Insect Damage in Radish with Floating Row Covers  

Microsoft Academic Search

Radish (Raphanus sativus L.) is a short season direct seeded crop with multiple seedlings starting as soon as the ground has thawed to ensure continuous supply. Floating row covers can be used to protect crops from low temperature to stimulate germination and to exclude insect pests. There is a need to optimize the use of floating row covers for early

Djamila Rekika; Katrine A. Stewart; Guy Boivin; Sylvie Jenni

2008-01-01

409

Enhanced integral imaging system using image floating technique  

Microsoft Academic Search

Enhanced integral imaging system based on the image floating method is proposed. The integral imaging is one of the most promising methods among the autostereoscopic displays and the integrated image has the volumetric characteristics unlike the other stereoscopic images. The image floating is a common 3D display technique, which uses a big convex lens or a concave mirror to exhibit

Sung-Wook Min; Joohwan Kim; Byoungho Lee

2005-01-01

410

46 CFR 131.870 - Life floats and buoyant apparatus.  

Code of Federal Regulations, 2010 CFR

...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

2010-10-01

411

46 CFR 131.870 - Life floats and buoyant apparatus.  

Code of Federal Regulations, 2013 CFR

...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

2013-10-01

412

46 CFR 131.870 - Life floats and buoyant apparatus.  

Code of Federal Regulations, 2012 CFR

...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

2012-10-01

413

46 CFR 131.870 - Life floats and buoyant apparatus.  

Code of Federal Regulations, 2011 CFR

...CONTINUED) OFFSHORE SUPPLY VESSELS OPERATIONS Markings for Fire Equipment and Emergency Equipment § 131.870 Life floats...at least 38 millimeters (1-1/2 inches) high and in a color contrasting to that of the float or apparatus. This number...

2011-10-01

414

A FLOATING-FISH SNARE FOR CAPTURING BALD EAGLES  

Microsoft Academic Search

Bald Eagles (Haliaeetus leucocephalus) were captured using a system of 4 monofilament snares fixed on a small (20-24 cm) floating fish attached by monofilament and shock cord to a free- floating (or anchored) driftwood log. When an eagle strikes the bait and begins to fly away, the snare loops close around the bird's toes as the line tightens. Resistance of

STEVEN L. CAIN; JOHN I. HODGES

415

Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint  

Microsoft Academic Search

This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offshore wind turbines in water depths of 10-200 m. Methods for the coupled structural, hydrodynamic, and aerodynamic analysis of floating wind turbine systems are presented in the

E. N. Wayman; P. D. Sclavounos; S. Butterfield; J. Jonkman; W. Musial

2006-01-01

416

On the Modelling of a Floating Offshore Wind Turbine  

Microsoft Academic Search

The location of wind turbines on floating structures offshore would allow an immense resource to be tapped without the drawbacks large developments can have on public opinion. There are, however, potentially significant technical and cost drawbacks. This article describes the theory and results of research work aimed at developing analytical tools for evaluating the performance of floating offshore wind farms.

Andrew R. Henderson; Minoo H. Patel

2003-01-01

417

An Advanced Method to Estimate Deep Currents from Profiling Floats  

Microsoft Academic Search

Subsurface ocean currents can be estimated from the positions of drifting profiling floats which are being widely deployed for the international ARGO program. The calculation of subsurface velocity depends on how the trajectory of the float while on the surface is treated. We address three aspects of the calculation of drift velocities: accurate determination of surfacing and dive times; a

Jong Jin Park; Kuh Kim; Brian A. King; Stephen C. Riser

2005-01-01

418

The behavior of active bactericidal and antifungal coating under visible light irradiation  

NASA Astrophysics Data System (ADS)

In the present paper, the novel active bactericidal and antifungal coatings (ABAC) have been prepared through the immobilization of Fe-doped TiO2 (anatase) with chitosan. The characterization of ABAC using optical microscope imaging, SEM, AFM and FTIR shows that the Fe doped TiO2 is embedded into the chitosan coating with favorable dispersion through the hydrogen bonds interaction between chitosan molecules and TiO2. The contact angle measurement demonstrated the hydrophilicity of ABAC (? = 34.5 ± 4.1°). The bactericidal activity of ABAC has been evaluated by inactivating three different test strains: Escherichia coli, Candida albicans and Aspergillus niger which illustrates the apparently higher bactericidal ability than chitosan, Fe-TiO2 and chitosan/TiO2 (pure) under visible light irradiation and its bactericidal activity is lasting for at least 24 h. ABAC showed rapid and efficient antibacterial ability for the three tested strains and its antibacterial ratio in 2 h for E. coli, C. albicans and A. niger was 99.9%, 97.0% and 95.0%, respectively. The prepared chitosan/TiO2 composite emulsion shows favorable storage stability and can be stored up to 1 year without losing its bactericidal activity. ABAC is a low-cost and eco-friendly antibacterial coating products and promising for domestic, medical and industrial applications.

Xiao, Gang; Zhang, Xiaodong; Zhao, Yan; Su, Haijia; Tan, Tianwei

2014-02-01

419

Light-induced antifungal activity of TiO 2 nanoparticles/ZnO nanowires  

NASA Astrophysics Data System (ADS)

Antifungal activity of TiO 2/ZnO nanostructures under visible light irradiation was investigated. A simple chemical method was used to synthesize ZnO nanowires. Zinc acetate dihydrate, Polyvinyl Pyrrolidone and deionized water were used as precursor, capping and solvent, respectively. TiO 2 nanoparticles were deposited on ZnO nanowires using an atmospheric pressure chemical vapor deposition system. X-ray diffraction pattern of TiO 2/ZnO nano-composite has represented the diffraction peaks relating to the crystal planes of the TiO 2 (anatase and rutile) and ZnO. TiO 2/ZnO nanostructure antifungal effect on Candida albicans biofilms was studied and compared with the activity of TiO 2 nanoparticles and ZnO nanowires. The high efficiency photocatalytic activity of TiO 2 nanoparticles leads to increased antifungal activity of ZnO nanowires. Scanning electron microscope was utilized to study the morphology of the as prepared nanostructures and the degradation of the yeast.

Haghighi, N.; Abdi, Y.; Haghighi, F.

2011-09-01

420

UV light activates a G?q/11-coupled phototransduction pathway in human melanocytes  

PubMed Central

While short exposure to solar ultraviolet radiation (UVR) can elicit increased skin pigmentation, a protective response mediated by epidermal melanocytes, chronic exposure can lead to skin cancer and photoaging. However, the molecular mechanisms that allow human skin to detect and respond to UVR remain incompletely understood. UVR stimulates a retinal-dependent signaling cascade in human melanocytes that requires GTP hydrolysis and phospholipase C ? (PLC?) activity. This pathway involves the activation of transient receptor potential A1 (TRPA1) ion channels, an increase in intracellular Ca2+, and an increase in cellular melanin content. Here, we investigated the identity of the G protein and downstream elements of the signaling cascade and found that UVR phototransduction is G?q/11 dependent. Activation of G?q/11/PLC? signaling leads to hydrolysis of phosphatidylinositol (4,5)-bisphosphate (PIP2) to generate diacylglycerol (DAG) and inositol 1, 4, 5-trisphosphate (IP3). We found that PIP2 regulated TRPA1-mediated photocurrents, and IP3 stimulated intracellular Ca2+ release. The UVR-elicited Ca2+ response appears to involve both IP3-mediated release from intracellular stores and Ca2+ influx through TRPA1 channels, showing the fast rising phase of the former and the slow decay of the latter. We propose that melanocytes use a UVR phototransduction mechanism that involves the activation of a G?q/11-dependent phosphoinositide cascade, and resembles light phototransduction cascades of the eye. PMID:24470488

Bellono, Nicholas W.; Najera, Julia A.

2014-01-01

421

Activation of tat-defective human immunodeficiency virus by ultraviolet light  

SciTech Connect

Ultraviolet light (UV) is known to cause activation of gene expression from the human immunodeficiency virus type 1 (HIV-1) promoter. To address the question of whether tat-defective HIV-1 provirus could be rescued by UV irradiation we examined its effect on HeLa cells containing integrated proviruses with tat mutations. Exposure of these cells to an optimal dose of UV resulted in the production of infectious viruses. The degree of UV activation and reversion to infectious virus appeared to depend on the nature of the original tat mutation. Two of the mutants required cocultivation with tat-expressing cells to fully generate replication competent viruses, while a third mutant required only cocultivation with H9 cells. Sequencing of cDNA from cells infected with this last mutant demonstrated that the parental mutant sequence was retained and that genotypic revertants to the wild-type as well as new mutant sequences were generated. These results suggest that tat-defective HIV-1 provirus can be activated by UV and can subsequently revert to wild-type virus. This study raises the possibility that UV exposure of immune cells in the skin plays a role in the activation of defective HIV-1 in vivo.

Sadaie, M.R.; Tschachler, E.; Valerie, K.; Rosenberg, M.; Felber, B.K.; Pavlakis, G.N.; Klotman, M.E.; Wong-Staal, F. (National Institutes of Health, Bethesda, MD (USA))

1990-05-01

422

Light Box  

NSDL National Science Digital Library

Learn how to construct a light box by following simple figures and instructions. This guide includes tips on how to assemble a light box; related activities are featured in separate resources. Learners can assist in the building process.

Rathjen, Don

2003-01-01

423

Children's knowledge of hierarchical phrase structure: quantifier floating in Japanese.  

PubMed

The interpretation of floating quantifiers in Japanese requires knowledge of hierarchical phrase structure. However, the input to children is insufficient or even misleading, as our analysis indicates. This presents an intriguing question on learnability: do children interpret floating quantifiers based on a structure-dependent rule which is not obvious in the input or do they employ a sentence comprehension strategy based on the available input? Two experiments examined four- to six-year-old Japanese-speaking children for their interpretations of floating quantifiers in SOV and OSV sentences. The results revealed that no child employed a comprehension strategy in terms of the linear ordering of constituents, and most five- and six-year-olds correctly interpreted floating quantifiers when word-order difficulty was reduced. These facts indicate that children's interpretation of floating quantifiers is structurally dependent on hierarchical phrase structure, suggesting that this knowledge is a part of children's grammar despite the insufficient input available to them. PMID:22850618

Suzuki, Takaaki; Yoshinaga, Naoko

2013-06-01

424

Informal Activities with Lasers, Lights, and Lenses: The Hands-On Optics Project  

NASA Astrophysics Data System (ADS)

The Hands-On Optics project began as a follow-up to the 2001 NSF planning grant "Optics Education -- A Blueprint for the 21st Century", which described the value of informal science programs in addressing the disconnect between the ubiquity of optics in everyday life and the noticeable absence of optics education in K-12 curricula and in informal science education programs. Key partners in the project are NOAO, SPIE-The International Society for Optical Engineering, and the Optical Society of America (OSA). The informal instructional materials created by the project are distributed through science centers nationwide and through the Mathematics, Engineering, Science Achievement Program (MESA) in a number of states, including Arizona, California, Washington, and Maryland. A key part of the project is the involvement, modeled after Project ASTRO, of optics professionals currently engaged in outreach activities and programs. Optics professionals (termed optics resource volunteers) are teamed with MESA and science center educators in implementing the program. These hands-on, high-interest, standards-connected activities and materials provide 6, three-hour-long optics activity modules that can be used in a variety of informal settings. We will describe the techniques used at NOAO to train educators, parents, and optics professionals who will work with the HOO activities as well as the different approaches needed for different informal education programs, ranging from Saturday programs, after-school programs, and science center programs. NOAO is developing the six modules and associated kits as well as competitions that have broad appeal to 12-year olds. Hands-On Optics: Making an Impact with Light (HOO) is a collaborative NSF-funded four-year informal science education program to excite students about science by actively engaging them in optics activities. NOAO is operated by the Association of Universities for Research in Astronomy (AURA), Inc. under cooperative agreement with the National Science Foundation.

Pompea, S. M.; Sparks, C. E.; Sparks, R. T.

2005-12-01

425

A Web Resource for Lab Activities Using SEM, EDX and Light Microscopy  

NASA Astrophysics Data System (ADS)

A resource that facilitates undergraduate activities centered on the development of perthitic textures is available at http://www.geosci.ipfw.edu/sem/semedx.html. The web site provides a coherent set of data and images from a perthite and an anorthoclase sample. Backscatter and secondary electron images, plane- and cross-polarized light images, energy dispersive X-ray (EDX) data from 13 points on the perthite and 31 points on the anorthoclase (including spectra and results files with data expressed as wt. and atomic percents) and X-ray diffraction (XRD) data are available. Care has been taken to match the areas examined by light and electron methods, allowing students to directly compare the data available from each technique. Brief descriptions of the various methods are provided. The available information can be the basis for many different exercises. Those without easy access to mircoprobes or EDX spectrometers will find the spectra useful for discussions of microchemical techniques. Different phases can be identified in the light and SEM images. The chemical results can be used to calculate formulas. (In addition to the feldspar, the anorthoclase phenocryst contains olivine, clinopyroxene, ulvospinel, apatite and glass.) Feldspar compositions can be plotted to illustrate compositional differences in perthite and anorthoclase. Glass compositions from the interior and margins of the anorthoclase phenocrysts can be compared. Numerous other possibilities, of varying levels of complexity, exist. The perthite (from Perth, Ontario) and the anorthoclase (from Mt. Erebus, Antarctica) were purchased from Wards Natural Science. There are many students with little or no access to data derived from EDX, SEM, XRD and similar techniques. It is our responsibility to find ways to make this information more universally available to all students.

Argast, A.; Tennis, C. F.

2003-12-01

426

[Photosynthetic fluorescence characteristics of floating-leaved and submersed macrophytes commonly found in Taihu Lake].  

PubMed

Some aquatic macrophytes commonly found in Taihu Lake, including Trapa bispinosa, Nymphyoides peltatum, Vallisneria natans, and Hydrilla verticillata were collected, and their maximal quantum yield of photosystem II (Fv/Fm) as well as the rapid light curves (RLCs) under conditions of light adaptation and dark adaptation were measured in situ by using a submersible and pulse-amplitude modulated fluorometer (Diving-PAM). The results showed that floating-leaved plants T. bispinosa and N. peltatum had higher potential maximum photosynthetic capacity than submerged macrophytes V. natans and H. verticillata. The measured maximal quantum yield of T. bispinosa, N. peltatum, V. natans, and H. verticillata was 0.837, 0.831, 0.684, and 0.764, respectively. Both the maximal relative electron transport rate and the half saturation point of light intensity of T. bispinosa and N. peltatum were higher than those of V. natans and H. verticillata, especially under the condition of light adaptation. PMID:19637593

Song, Yu-zhi; Cai, Wei; Qin, Bo-qiang

2009-03-01

427

Structural changes of a light-activated G protein-coupled receptor determined by solid-state NMR: Channeling light energy into the visual pigment rhodopsin  

Microsoft Academic Search

Absorption of light by the visual pigment rhodopsin triggers an 11- cis to all-trans isomerization of the retinal chromophore within the interior of this G protein-coupled receptor. Two-dimensional solid-state NMR of rhodopsin and the active metarhodopsin II intermediate is used to determine the trajectory of the retinal and the effects of retinal isomerization on the structure of the protein. Structural

Evan Daniel Crocker

2005-01-01

428

Highly active WO3-Ag-ZnO photocatalyst driven by day light illumination  

NASA Astrophysics Data System (ADS)

The WO3 loaded Ag-ZnO (WO3-Ag-ZnO) was successfully synthesized by precipitation-decomposition method. The catalyst was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) images, energy dispersive spectrum (EDS), transmission electron microscope (TEM), diffuse reflectance spectra (DRS), photoluminescence spectra (PL), cyclic voltammetry (CV) and BET surface area measurements. The photocatalytic activity of WO3-Ag-ZnO was investigated for the degradation of Naphthol Blue Black (NBB) in aqueous solution using solar light. WO3-Ag-ZnO is found to be more efficient than Ag-ZnO, WO3-ZnO, Ag-WO3, WO3, commercial ZnO, bare ZnO, TiO2-P25 and TiO2 (Merck) at pH 9 for the mineralization of NBB dye. The effects of operational parameters such as the amount of photocatalyst, dye concentration, initial pH on photo mineralization of NBB dye have been analyzed. The mineralization of NBB has been confirmed by Chemical Oxygen Demand (COD) measurements. A degradation mechanism is proposed for the degradation of NBB under solar light. This catalyst is found to be reusable.

Subash, B.; Krishnakumar, B.; Sreedhar, B.; Swaminathan, M.; Shanthi, M.

2013-02-01

429

Photoelectrochemical aptasensing of kanamycin using visible light-activated carbon nitride and graphene oxide nanocomposites.  

PubMed

Photoactive material and recognition element are two crucial factors which determine the sensitivity and selectivity of the photoelectrochemical (PEC) sensor. Herein we developed a novel PEC aptamer sensor for the specific detection of kanamycin using water-dispersible graphite-like carbon nitride (w-g-C3N4) as visible light-active material and aptamer as the biorecognition element. While a suitable amount of graphene oxide (GO) was doped in w-g-C3N4, the visible light photocurrent response was enhanced, which was beneficial to the construction of PEC sensor. On the other hand, the large specific surface area and ?-conjugated structure of GO/w-g-C3N4 provided an excellent platform for immobilizing the kanamycin-binding DNA aptamer on the surface of the sensor via ?-? stacking interaction. On such a sensor, the capture of kanamycin molecules by aptamer resulted in increased photocurrent. The PEC response of the sensor was found to be linearly proportional to the concentration of kanamycin in the range from 1 nM to 230 nM with a detection limit (3S/N) of 0.2 nM. Moreover, the proposed sensor displayed high selectivity, good reproducibility, and high stability, demonstrating the successful combination of GO/w-g-C3N4 with aptamer in fabricating high performance PEC sensors. PMID:25219771

Li, Ruizhen; Liu, Yong; Cheng, Ling; Yang, Changzhu; Zhang, Jingdong

2014-10-01

430

Development, Characterization and Photocatalytic Activities of BiYO3 Nanoparticles under Visible Light Irradiation  

NASA Astrophysics Data System (ADS)

BiYO3 photocatalysts were successfully synthesized as nanoparticles by sol-gel technique. The powder obtained after the calcination of the polymeric precursor at 600 °C was characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-vis) diffuse reflectance spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). The XRD analysis revealed that the synthesized material has a cubic perovskite (ABO3) structure. The particle size calculated from FWHM was ˜13 nm. TEM analysis confirmed the nanoscale (10-20 nm) nature of the powder. FT-IR and EDX analyses have shown that the calcined powder is phase pure. UV-vis diffuse reflectance spectroscopy revealed that the crystalline BiYO3 had a band gap of 2.95 eV. This indicated that BiYO3 might perform well as a photocatalyst in the visible light region. Photocatalytic activity of BiYO3 nanoparticles was investigated for the degradation of methyl orange under visible light irradiation.

Kumar, V. Ratheesh; Wariar, P. R. S.; Prasad, V. S.; Koshy, J.

2011-10-01

431

Anti-cardiolipin/beta-2 glycoprotein activities co-exist on human anti-DNA antibody light chains.  

PubMed

We have recently shown that the human anti-DNA antibodies B3 and 33H11 also bind cardiolipin and that the anti-autoantigen activity resides predominantly on their lambda light chains. We now show that the two auto-antibodies possess strong reactivity to the plasma-protein 2-Glycoprotein I (beta2-GPI) also. Utilizing chain shuffling experiments involving an unrelated anti-p185 antibody 4D5 with insignificant reactivity to cardiolipin or to beta2-GPI, we now demonstrate that hybrid Fabs with constituent light chain, but not the heavy chain, of B3 or 33H11, exhibit anti-cardiolipin activity. Furthermore, the constructs possessing the auto-antibody-derived light chain also exhibited significant reactivity to beta2-GPI. The results suggest that anti-DNA, anti-cardiolipin and anti-beta2-GPI activities co-exist on the light chains of the antibodies studied and, importantly, these activities could be transferred to antibody constructs by their light chains alone. Computer-generated models of the three-dimensional structures of the auto-antibodies and their hybrids, suggest predominant interaction of their light chains with domain IV of beta2-GPI. PMID:14563371

Kumar, Sanjeev; Nagl, Sylvia; Kalsi, J K; Ravirajan, C T; Athwal, Dee; Latchman, David S; Pearl, Laurence H; Isenberg, David A

2003-12-01

432

Development of White-Light Emitting Active Layers in Nitride Based Heterostructures for Phosphorless Solid State Lighting  

Microsoft Academic Search

This report provides a summary of research activities carried out at the University of California, San Diego and Central Research of OSRAM SYLVANIA in Beverly, MA partially supported by a research contract from US Department of Energy, DE-FC26-04NT422274. The main objective of this project was to develop III-V nitrides activated by rare earth ions, RE{sup 3+}, which could eliminate the

Jan Talbot; Kailash Mishra

2007-01-01

433

Fullerene modification CdSe/TiO2 and modification of photocatalytic activity under visible light  

PubMed Central

CdSe, CdSe-TiO2, and CdSe-C60/TiO2 composites were prepared using sol–gel method, and their photocatalytic activity was evaluated by measuring the degradation of rhodamine B solutions under visible light. The surface area, surface structure, crystal phase, and elemental identification of these composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV-visible (vis) absorption spectrophotometry. XRD showed that the CdSe-C60/TiO2 composite contained a typical single and clear anatase phase. SEM of the CdSe-C60/TiO2 composites revealed a homogenous composition in the particles. EDX revealed the presence of C and Ti with strong Cd and Se peaks in the CdSe-C60/TiO2 composite. The degradation of dye was determined by UV–vis spectrophotometry. An increase in photocatalytic activity was observed and attributed to an increase in the photoabsorption effect by fullerene and the cooperative effect of the CdSe. The repeatability of photocatalytic activity was also tested in order to investigate the stability of C60 and CdS-C60/TiO2 composites. PMID:23618055

2013-01-01

434

Fullerene modification CdSe/TiO2 and modification of photocatalytic activity under visible light.  

PubMed

CdSe, CdSe-TiO2, and CdSe-C60/TiO2 composites were prepared using sol-gel method, and their photocatalytic activity was evaluated by measuring the degradation of rhodamine B solutions under visible light. The surface area, surface structure, crystal phase, and elemental identification of these composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV-visible (vis) absorption spectrophotometry. XRD showed that the CdSe-C60/TiO2 composite contained a typical single and clear anatase phase. SEM of the CdSe-C60/TiO2 composites revealed a homogenous composition in the particles. EDX revealed the presence of C and Ti with strong Cd and Se peaks in the CdSe-C60/TiO2 composite. The degradation of dye was determined by UV-vis spectrophotometry. An increase in photocatalytic activity was observed and attributed to an increase in the photoabsorption effect by fullerene and the cooperative effect of the CdSe. The repeatability of photocatalytic activity was also tested in order to investigate the stability of C60 and CdS-C60/TiO2 composites. PMID:23618055

Meng, Ze-Da; Zhu, Lei; Ye, Shu; Sun, Qian; Ullah, Kefayat; Cho, Kwang-Youn; Oh, Won-Chun

2013-01-01

435

Fullerene modification CdSe/TiO2 and modification of photocatalytic activity under visible light  

NASA Astrophysics Data System (ADS)

CdSe, CdSe-TiO2, and CdSe-C60/TiO2 composites were prepared using sol-gel method, and their photocatalytic activity was evaluated by measuring the degradation of rhodamine B solutions under visible light. The surface area, surface structure, crystal phase, and elemental identification of these composites were characterized by nitrogen adsorption isotherms, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and UV-visible (vis) absorption spectrophotometry. XRD showed that the CdSe-C60/TiO2 composite contained a typical single and clear anatase phase. SEM of the CdSe-C60/TiO2 composites revealed a homogenous composition in the particles. EDX revealed the presence of C and Ti with strong Cd and Se peaks in the CdSe-C60/TiO2 composite. The degradation of dye was determined by UV-vis spectrophotometry. An increase in photocatalytic activity was observed and attributed to an increase in the photoabsorption effect by fullerene and the cooperative effect of the CdSe. The repeatability of photocatalytic activity was also tested in order to investigate the stability of C60 and CdS-C60/TiO2 composites.

Meng, Ze-Da; Zhu, Lei; Ye, Shu; Sun, Qian; Ullah, Kefayat; Cho, Kwang-Youn; Oh, Won-Chun

2013-04-01

436

Arrangement of RecA protein in its active filament determined by polarized-light spectroscopy  

PubMed Central

Linear dichroism (LD) polarized-light spectroscopy is used to determine the arrangement of RecA in its large filamentous complex with DNA, active in homologous recombination. Angular orientation data for two tryptophan and seven tyrosine residues, deduced from differential LD of wild-type RecA vs. mutants that were engineered to attenuate the UV absorption of selected residues, revealed a rotation by some 40° of the RecA subunits relative to the arrangement in crystal without DNA. In addition, conformational changes are observed for tyrosine residues assigned to be involved in DNA binding and in RecA–RecA contacts, thus potentially related to the global structure of the filament and its biological function. The presented spectroscopic approach, called “Site-Specific Linear Dichroism” (SSLD), may find forceful applications also to other biologically important fibrous complexes not amenable to x-ray crystallographic or NMR structural analysis. PMID:12193645

Morimatsu, Katsumi; Takahashi, Masayuki; Norden, Bengt

2002-01-01

437

Light-activated amino acid transport in Halobacterium halobium envelope vesicles  

NASA Technical Reports Server (NTRS)

Vesicles prepared from Halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. Nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created Na+ gradient. On the basis of shared common carriers the transport systems can be divided into eight classes, each responsible for the transport of one or several amino acids: arginine, lysine, histidine; asparagine, glutamine; alanine, glycine, threonine, serine; leucine, valine, isoleucine, methionine; phenylalanine, tyrosine, tryptophan; aspartate; glutamate; proline. Available evidence suggests that these carriers are symmetrical in that amino acids can be transported equally well in both directions across the vesicle membranes. A tentative working model to account for these observations is presented.

Macdonald, R. E.; Lanyi, J. K.

1977-01-01

438

Active imaging systems to see through adverse conditions: Light-scattering based models and experimental validation  

NASA Astrophysics Data System (ADS)

Onera, the French aerospace lab, develops and models active imaging systems to understand the relevant physical phenomena affecting these systems performance. As a consequence, efforts have been done on the propagation of a pulse through the atmosphere and on target geometries and surface properties. These imaging systems must operate at night in all ambient illumination and weather conditions in order to perform strategic surveillance for various worldwide operations. We have implemented codes for 2D and 3D laser imaging systems. As we aim to image a scene in the presence of rain, snow, fog or haze, we introduce such light-scattering effects in our numerical models and compare simulated images with measurements provided by commercial laser scanners.

Riviere, Nicolas; Ceolato, Romain; Hespel, Laurent

2014-10-01

439

Towards an electronic nose based on nano-structured transition metal oxides activated by a tuneable UV light source  

Microsoft Academic Search

Traditional gas sensors involve heating the sensor material for gas selectivity. New gas approaches require activation by a broadband UV light source. We propose to employ a tuneable UV source in which this source is tuned for its many wavelengths via a grating and associated optics and transducers. The theory of UV activated gas sensing is presented and the first

Bonex Wakufwa Mwakikunga; Thomas Malwela; Kenneth Thembela Hillie; Gebhu Ndlovu

2011-01-01

440

Deep ultraviolet emitting polarization induced nanowire light emitting diodes with AlxGa1?xN active regions  

NASA Astrophysics Data System (ADS)

In this report, we demonstrate band gap tuning of the active region emission wavelength from 365 nm to 250 nm in light emitting diodes fashioned from catalyst-free III-nitride nanowires. Optical characteristics of the nanowire heterostructures and fabricated devices are studied via electroluminescence (EL) and photoluminescence spectroscopy over a wide range of active region compositions. It is observed that for typical nanowire plasma assisted molecular beam epitaxy growth conditions, tuning of emission to wavelengths shorter than 300 nm is hampered by the presence of an optically active defect level. We show that by increasing the AlGaN nanowire growth temperatures this defect emission can be suppressed. These findings are applied to growth of the active region of a nanowire light emitting diode, resulting in a polarization-induced nanowire light emitting diode with peak EL at 250 nm.

Kent, Thomas F.; Carnevale, Santino D.; Sarwar, A. T. M.; Phillips, Patrick J.; Klie, Robert F.; Myers, Roberto C.

2014-11-01

441

Synthesis and utilization of reversible and irreversible light-activated nanovalves derived from the channel protein MscL.  

PubMed

This protocol details the chemical modification of the mechanosensitive channel of large-conductance (MscL) channel protein into a light-activated nanovalve and its utilization for triggered delivery in synthetic liposomal vesicles. It is based on charge-induced activation of this otherwise mechanosensitive channel by covalent attachment to the protein of rationally designed synthetic functionalities. In the dark, these functionalities will be uncharged and the channel will stay closed, but UV illumination will cause their ionization and trigger channel activity. In the case of reversible activation, subsequent illumination with visible light will neutralize the charge, causing the channel to close. The protocol includes synthesis of light-responsive compounds, protein isolation and its chemical labeling, reconstitution of the protein into artificial membranes, its analysis at the single-molecule level and its application in liposomal delivery. The whole protocol takes 4 days. Unlike mutagenesis, this method allows the introduction of custom-designed functional groups. PMID:17545979

Koçer, Arma?an; Walko, Martin; Feringa, Ben L

2007-01-01

442

Deep ultraviolet emitting polarization induced nanowire light emitting diodes with AlxGa1-xN active regions.  

PubMed

In this report, we demonstrate band gap tuning of the active region emission wavelength from 365 nm to 250 nm in light emitting diodes fashioned from catalyst-free III-nitride nanowires. Optical characteristics of the nanowire heterostructures and fabricated devices are studied via electroluminescence (EL) and photoluminescence spectroscopy over a wide range of active region compositions. It is observed that for typical nanowire plasma assisted molecular beam epitaxy growth conditions, tuning of emission to wavelengths shorter than 300 nm is hampered by the presence of an optically active defect level. We show that by increasing the AlGaN nanowire growth temperatures this defect emission can be suppressed. These findings are applied to growth of the active region of a nanowire light emitting diode, resulting in a polarization-induced nanowire light emitting diode with peak EL at 250 nm. PMID:25327762

Kent, Thomas F; Carnevale, Santino D; Sarwar, A T M; Phillips, Patrick J; Klie, Robert F; Myers, Roberto C

2014-11-14

443

Photocatalytic activity of non-stoichiometric ZnFe2O4 under visible light irradiation  

NASA Astrophysics Data System (ADS)

Nanostructured zinc ferrites with different excess iron contents (ZnFe2+zO4, where z = 0.00, 0.05, 0.10 and 0.15) have been synthesized using the sol-gel auto-combustion method. The effect of excess iron on the structural, optical and visible light photocatalytic activity of zinc ferrite samples has been investigated. X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), x-ray magnetic circular dichroism (XMCD), Brunauer-Emmett-Teller theory, scanning electron microscopy (SEM), diffuse reflectance spectroscopy (UV-Vis) and photoluminescence spectroscopy were used to characterize the synthesized non-stoichiometric ZnFe2O4 powders. The XRD patterns demonstrated that the samples consist of single phase spinel structure with crystallite sizes of ˜25 nm. SEM analysis indicated that the nanosized particles grow together in porous clusters with a size of several microns. The XPS and XMCD analyses revealed that the excess iron ion substitutes Zn2+ in tetrahedral sites and in octahedral sites Fe2+ can be found in addition to Fe3+, which could be created to restore the overall charge balance in the crystal lattice. Stoichiometric zinc ferrite (ZnFe2+zO4, z = 0.00) exhibited higher photocatalytic activity (40%) than the excess iron sample (ZnFe2+zO4, z = 0.15, i.e. 4%) under visible light irradiation for 3 h. This was explained by the formation of Fe2+ in the octahedral sites of excess iron ZnFe2O4; these species act as recombination centres.

Šutka, A.; Pärna, R.; Kleperis, J.; Käämbre, T.; Pavlovska, I.; Korsaks, V.; Malnieks, K.; Grinberga, L.; Kisand, V.

2014-04-01

444

Visible-light-activated photoelectrochemical biosensor for the study of acetylcholinesterase inhibition induced by endogenous neurotoxins.  

PubMed

In this report, a novel visible-light-activated photoelectrochemical biosensor was fabricated to study the inhibition of acetylcholinesterase (AChE) activity induced by two endogenous neurotoxins, 1(R)-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline [(R)-Sal] and 1(R),2(N)-dimethyl-6,7-dihydroxy-1,2,3,4-tetra-hydroisoquinoline [(R)-NMSal], which have drawn much attention in the study of the pathogenesis of neurodegenerative diseases such as Parkinson's disease. The photoelectrode was prepared by three steps, as follows. At first, nitrogen and fluorine co-doped TiO2 nanotubes (TNs) were obtained by anodic oxidation of a Ti sheet. Secondly, silver nanoparticles (AgNPs) were deposited onto the TNs through a microwave-assisted heating polyol (MAHP) process. At last, AChE was immobilized on the obtained photoelectrode and the biosensor was marked as AChE/Ag/N?F?TNs. Due to the nitrogen and fluorine co-doping, the photoelectrochemical biosensors can produce high photocurrent under visible light irradiation. Moreover, the presence of AgNPs greatly increased the photocurrent response of the biosensor. AChE/Ag/N?F?TNs hybrid system was used to study AChE inhibition induced by (R)-Sal and (R)-NMSal. The result proved that both (R)-Sal and (R)-NMSal exhibited mixed and reversible inhibition against AChE. This strategy is of great significance for the development of novel photoelectrochemical biosensors in the future. PMID:23500378

Huang, Qilin; Chen, Hua; Xu, Lili; Lu, Danqin; Tang, Linlin; Jin, Litong; Xu, Zhiai; Zhang, Wen

2013-07-15

445

UFO: "Unidentified" Floating Object Driven by Thermocapillarity  

E-print Network

In this fluid dynamics video, we show thermocapillary actuation of a binary drop of water and heptanol where the binary drop in motion takes on a UFO-like shape. On a parylene-coated silicon surface subjected to a linear temperature gradient, a pure heptanol droplet quickly moves to the cold side by the Marangoni stress, while a pure water droplet remains stuck due to a large contact angle hysteresis. When the water droplet was encapsulated by a thin layer of heptanol and thermally actuated, the binary droplet takes on a peculiar shape resembling an UFO, i.e. an "unidentified" floating object as the mechanism is not yet completely understood. Our finding suggests that pure liquid droplets (e.g. aqueous solutions) that are not conducive to thermocapillary actuation can be made so by encapsulating them with another judiciously chosen liquid (e.g. heptanol).

Zhao, Yuejun

2010-01-01

446

Microfluidic quadrupole and floating concentration gradient  

PubMed Central

The concept of fluidic multipoles, in analogy to electrostatics, has long been known as a particular class of solutions of the Navier-Stokes equation in potential flows, however, experimental observations of fluidic multipoles and of their characteristics have not been reported yet. Here we present a two-dimensional microfluidic quadrupole and a theoretical analysis consistent with the experimental observations. The microfluidic quadrupole was formed by simultaneously injecting and aspirating fluids from two pairs of opposing apertures in a narrow gap formed between a microfluidic probe and a substrate. A stagnation point was formed at the center of the microfluidic quadrupole, and its position could be rapidly adjusted hydrodynamically. Following the injection of a solute through one of the poles, a stationary, tunable, and movable – i.e. “floating” – concentration gradient was formed at the stagnation point. Our results lay the foundation for future combined experimental and theoretical exploration of microfluidic planar multipoles including convective-diffusive phenomena. PMID:21897375

Qasaimeh, Mohammad A.; Gervais, Thomas; Juncker, David

2014-01-01

447

Effects of Dislocations on Minority Carrier Lifetime in Dislocated Float Zone Silicon  

SciTech Connect

We present a correlation of Microwave Photoconductance Decay minority carrier lifetime with dislocation density in high purity Float Zone silicon. Electron Beam Induced Current (EBIC) images were carefully aligned to lifetime maps and depth profiling of individual defect electrical activity was done by varying the bias of Schottky diodes. The data presented provides a relationship between lifetime variations and EBIC contrast, based on dislocation density and impurity decoration in the near surface zone.

Karoui, A.; Zhang, R.; Rozgonyi, G. A.; Ciszek, T. F.

2002-08-01

448

Influence of light and pH on growth and nitrogenase activity on temperate-grown Azolla  

Microsoft Academic Search

We investigated the influence of light intensity and pH on growth and acetylene reduction in three strains of Azolla filiculoides and one strain of A. pinnata cultivated under ambient conditions in Naples, Italy. A. pinnata showed maximum growth and acetylene reduction activity at 65% of natural light intensity (82 Klux) and at pH 5–7. In contrast, three A. filiculoides strains

A. Moretti; G. Siniscalco Gigliano

1988-01-01

449

Entrainment of the circadian rhythm in the rat pineal N-acetyltransferase activity by prolonged periods of light.  

PubMed

Entertainment of the circadian rhythm in the pineal N-acetyltranferase activity by prolonged periods of light was studied in rats synchronized with a light:dark regime of 12:12 h by observing phase-shifts in rhythm after delays in switching off the light in the evening or after bringing forward of the morning onset of light. When rats were subjected to delays in switching off the light of up to 10 h and then were released into darkness, phase-delays of the evening N-acetyltransferase rise during the same night corresponded roughly to delays in the light switch off. However, phase-delays of the morning decline were much smaller. After a delay in the evening switch off of 11 h, no N-acetyltransferase rhythm was found in the subsequent darkness. The evening N-acetyltransferase rise was phase-delayed by 6.2 h at most 1 day after delays. Phase-delays of the morning N-acetyltransferase decline were shorter than phase-delays of the N-acetyltransferase rise by only 0.7 h to 0.9 h at most. Hence, 1 day after delays in the evening switch off, the period of the high night N-acetyltransferase activity may be shortened only slightly. The N-acetyltransferase rhythm was abolished only after a 12 h delay in switching off the light. Rats were subjected to a bringing forward of the morning light onset and then were released into darkness 4 h before the usual switch off of light. In the following night, the morning N-acetyltransferase decline, but not the evening rise, was phase advanced considerably. Moreover, when the onset of light was brought forward to before midnight, the N-acetyltransferase rise was even phase-delayed. Hence, 1 day after bringing forward the morning onset of light, the period of the high night N-acetyltransferase activity may be drastically reduced. When rats were subjected to a 4 h light pulse around midnight and then released into darkness, the N-acetyltransferase rhythm in the next night was abolished. The data are discussed in terms of a two-component pacemaker controlling the N-acetyltransferase rhythm. It is suggested that delays in the evening switch off of light may disturb the N-acetyltransferase rhythm the next day only a little, as the morning component may adjust to phase-delays of the evening component almost within one cycle.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3668882

Illnerová, H; Van?cek, J

1987-08-01

450

Low Power, Red, Green and Blue Carbon Nanotube Enabled Vertical Organic Light Emitting Transistors for Active Matrix OLED Displays  

SciTech Connect

Organic semiconductors are potential alternatives to polycrystalline silicon as the semiconductor used in the backplane of active matrix organic light emitting diode displays. Demonstrated here is a light-emitting transistor with an organic channel, operating with low power dissipation at low voltage, and high aperture ratio, in three colors: red, green and blue. The single-wall carbon nanotube network source electrode is responsible for the high level of performance demonstrated. A major benefit enabled by this architecture is the integration of the drive transistor, storage capacitor and light emitter into a single device. Performance comparable to commercialized polycrystalline-silicon TFT driven OLEDs is demonstrated.

McCarthy, M. A. [University of Florida, Gainesville; Liu, B. [University of Florida, Gainesville; Donoghue, E. P. [University of Florida, Gainesville; Kravchenko, Ivan I [ORNL; Kim, D. Y. [University of Florida, Gainesville; So, Franky [University of Florida, Gainesville; Rinzler, A. G. [University of Florida, Gainesville

2011-01-01

451

Two-state model of light induced activation and thermal bleaching of photochromic glasses: theory and experiments.  

PubMed

The behavior of photochromic glasses during activation and bleaching is investigated. A two-state phenomenological model describing light-induced activation (darkening) and thermal bleaching is presented. The proposed model is based on first-order kinetics. We demonstrate that the time behavior in the activation process (acting simultaneously with the thermal fading) can be characterized by two relaxation times that depend on the intensity of the activating light. These characteristic times are lower than the decay times of the pure thermal bleaching process. We study the temporal evolution of the glass optical density and its dependence on the activating intensity. We also present a series of activation and bleaching experiments that validate the proposed model. Our approach may be used to gain more insight into the transmittance behavior of photosensitive glasses, which could be potentially relevant in a broad range of applications, e.g., real-time holography and reconfigurable optical memories. PMID:18617984

Ferrari, José A; Perciante, César D

2008-07-10

452

Self-efficacy enhancing intervention increases light physical activity in people with chronic obstructive pulmonary disease  

PubMed Central

Background People with chronic obstructive pulmonary disease lead sedentary lives and could benefit from increasing their physical activity. The purpose of this study was to determine if an exercise-specific self-efficacy enhancing intervention could increase physical activity and functional performance when delivered in the context of 4 months of upper body resistance training with a 12-month follow-up. Methods In this randomized controlled trial, subjects were assigned to: exercise-specific self-efficacy enhancing intervention with upper body resistance training (SE-UBR), health education with upper body resistance training (ED-UBR), or health education with gentle chair exercises (ED-Chair). Physical activity was measured with an accelerometer and functional performance was measured with the Functional Performance Inventory. Forty-nine people with moderate to severe chronic obstructive pulmonary disease completed 4 months of training and provided valid accelerometry data, and 34 also provided accelerometry data at 12 months of follow-up. The self-efficacy enhancing intervention emphasized meeting physical activity guidelines and increasing moderate-to-vigorous physical activity. Results Differences were observed in light physical activity (LPA) after 4 months of training, time by group interaction effect (P=0.045). The SE-UBR group increased time spent in LPA by +20.68±29.30 minutes/day and the other groups decreased time spent in LPA by ?22.43±47.88 minutes/day and -25.73±51.76 minutes/day. Changes in LPA were not sustained at 12-month follow-up. There were no significant changes in moderate-to-vigorous physical activity, sedentary time, or functional performance. Subjects spent most of their waking hours sedentary: 72%±9% for SE-UBR, 68%±10% for ED-UBR, and 74%±9% for ED-Chair. Conclusion The self-efficacy enhancing intervention produced a modest short-term increase in LPA. Further work is needed to increase the magnitude and duration of effect, possibly by targeting LPA. PMID:25336939

Larson, Janet L; Covey, Margaret K; Kapella, Mary C; Alex, Charles G; McAuley, Edward

2014-01-01

453

Development and evaluation of new sustained-release floating microspheres.  

PubMed

A type of multi-unit floating alginate (Alg) microspheres was prepared by the ionotropic gelation method with calcium carbonate (CaCO(3)) being used as gas-forming agent. Attempts were made to enhance the drug encapsulation efficiency and delay the drug release by adding chitosan (Cs) into the gelation medium and by coating with Eudragit, respectively. The gastrointestinal transit of optimized floating sustained-release microspheres was compared with that of the non-floating system manufactured from identical material using the technique of gamma-scintigraphy in healthy human volunteers. It was found that the drug encapsulation efficiency of Cs-Alg microspheres was much higher than that of the Ca-Alg microspheres, and coating the microspheres with Eudragit RS could extend the drug release significantly. Both uncoating and coating microspheres were able to continuously float over the simulated gastric fluid (SGF) for 24h in vitro. Prolonged gastric-retention time (GRT) of over 5h was achieved in the volunteer for the optimized coating floating microspheres (FM). In contrast, non-floating system (NFM) could be emptied within 2.5h. In the present study, a multi-unit system with excellent floating ability, optimum drug entrapment efficiency and suitable drug release pattern has been developed. PMID:18407442

Ma, Ninan; Xu, Lu; Wang, Qifang; Zhang, Xiangrong; Zhang, Wenji; Li, Yang; Jin, Lingyu; Li, Sanming

2008-06-24

454

Effect of timed bright light treatment for rest-activity disruption in institutionalized patients with Alzheimer's disease  

PubMed Central

SUMMARY Background Disturbances in rest-activity rhythm are prominent and disabling symptoms in Alzheimer’s disease (AD). Nighttime sleep is severely fragmented and daytime activity is disrupted by multiple napping episodes. In most institutional environments, light levels are very low and may not be sufficient to entrain the circadian clock to the 24-hour day. Method The purpose of this randomized clinical trial was to test the effectiveness of timed bright light therapy in reducing rest-activity (circadian) disruption in institutionalized patients with AD. The experimental groups received either morning (9.30–10.30 am) or afternoon (3.30–4.30 pm) bright light exposure (? 2500 lux in gaze direction) Monday through Friday for 10 weeks. The control group received usual indoor light (150–200 lux). Nighttime sleep, daytime wake, and rest-activity parameters were determined by actigraphy. Repeated measures analysis of variance was employed to test the primary study hypotheses. Results Seventy institutionalized subjects with AD (mean age 84) completed the study. No significant differences in actigraphy-based measures of nighttime sleep or daytime wake were found between groups. Subjects in either experimental light condition evidenced a significantly (p < 0.01) more stable rest-activity rhythm acrophase over the 10-week treatment period compared to the control subjects whose rhythm phase delayed by over two hours. Conclusions One hour of bright light, administered to subjects with AD either in the morning or afternoon, did not improve nighttime sleep or daytime wake compared to a control group of similar subjects. However, exposure to one-hour of bright light in either the morning or afternoon may provide sufficient additional input to the circadian pacemaker to facilitate entrainment to the 24-hour day. PMID:16035127

Dowling, Glenna A.; Mastick, Judy; Hubbard, Erin M.; Luxenberg, Jay S.; Burr, Robert L.

2008-01-01

455

The effect of light quality and quantity on the flight activity of the adult hickory shuckworm Laspeyresia caryana (Fitch  

E-print Network

is insensitive to exogenous stimuli until near the end of each 24-hour period. The daily flight activity of the fruit fly ~Droso hila robusta (Sturtevant) shows a close similarity to that observed for the hickory shuckworm (Roberts 1956). Flight activity... exhibited by D. robusta adults in the field became maximal just before sunset when light intensity ranged between 100 ft. -c. and 15 ft. -c. Lab- oratory investigations indicated that the occurrence of the activ- ity period was determined by a biological...

Teel, Pete Don