Note: This page contains sample records for the topic floating light activated from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: August 15, 2014.
1

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.

Abdo, Ammar; Sahin, Mesut

2011-01-01

2

Floating light-activated microelectrical stimulators tested in the rat spinal cord.  

PubMed

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 microelectrical 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 1.08 N, 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

2011-10-01

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.

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

2011-01-01

4

Floating light-activated microelectrical stimulators tested in the rat spinal cord  

NASA Astrophysics Data System (ADS)

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 microelectrical 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 1.08 N, 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.

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

2011-10-01

5

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

Code of Federal Regulations, 2013 CFR

...are the requirements for lights on a floating hose string? 149.550 Section... Aids to Navigation Lights on Floating Hose Strings § 149.550 What are the requirements for lights on a floating hose string? Hose strings...

2013-07-01

6

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

Code of Federal Regulations, 2010 CFR

...are the requirements for lights on a floating hose string? 149.550 Section... Aids to Navigation Lights on Floating Hose Strings § 149.550 What are the requirements for lights on a floating hose string? Hose strings...

2009-07-01

7

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

Code of Federal Regulations, 2010 CFR

...are the requirements for lights on a floating hose string? 149.550 Section... Aids to Navigation Lights on Floating Hose Strings § 149.550 What are the requirements for lights on a floating hose string? Hose strings...

2010-07-01

8

Broad-band, lossless monolithic microwave active floating inductor  

Microsoft Academic Search

A broadband, lossless microwave active floating inductor is proposed for general use in monolithic microwave integrated circuits. The attractive features of this active floating inductor are that (1) it is lossless, (2) it can operate over a wide microwave frequency range, (3) its size is independent of the inductance value, and (4) it can be easily made using MMIC technology

Guang Fei Zhang; J. L. Gautier

1993-01-01

9

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

10

CMOS Active-Pixel Image Sensor With Simple Floating Gates  

NASA Technical Reports Server (NTRS)

Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

1996-01-01

11

Floating electrode optoelectronic tweezers: Light-driven dielectrophoretic droplet manipulation in electrically insulating oil medium  

Microsoft Academic Search

We report an optical actuation mechanism, floating electrode optoelectronic tweezers (FEOET). FEOET enables light-driven transport of aqueous droplets immersed in electrically insulating oil on a featureless photoconductive glass layer with direct optical images. We demonstrate that a 681 mum de-ionized water droplet immersed in corn oil medium is actuated by a 3.21 muW laser beam with an average intensity as

Chenlu Pan; Ting-Hsiang Wu; Christoph Kloss; Sheraz Kalim; Caitlin E. Callahan; Michael Teitell; Eric P. Y. Chiou

2008-01-01

12

A 360-degree floating 3D display based on light field regeneration.  

PubMed

Using light field reconstruction technique, we can display a floating 3D scene in the air, which is 360-degree surrounding viewable with correct occlusion effect. A high-frame-rate color projector and flat light field scanning screen are used in the system to create the light field of real 3D scene in the air above the spinning screen. The principle and display performance of this approach are investigated in this paper. The image synthesis method for all the surrounding viewpoints is analyzed, and the 3D spatial resolution and angular resolution of the common display zone are employed to evaluate display performance. The prototype is achieved and the real 3D color animation image has been presented vividly. The experimental results verified the representability of this method. PMID:23669981

Xia, Xinxing; Liu, Xu; Li, Haifeng; Zheng, Zhenrong; Wang, Han; Peng, Yifan; Shen, Weidong

2013-05-01

13

A large-active-area light-blocking based switch for people with disability  

Microsoft Academic Search

This paper proposes a force-free large-active-area light-blocking based switch structure. Our key approach is based on a combination of three basic optical concepts: optical beam shaping (S) that converts an incident optical beam into a diverging sheet of light beam across a desired active area, optical beam floating (F) that allows the sheet of light beam float above the desired

Sarun Sumriddetchkajorn; Ratthasart Amarit

2007-01-01

14

"JCE" Classroom Activity #108. Using Archimedes' Principle to Explain Floating and Sinking Cans  

ERIC Educational Resources Information Center

In this activity, students (working alone or in groups) measure the mass of several soda cans (diet and regular soda) along with the mass of water that each can displaces. The students are then asked to compare these two mass values for the sinking cans and for the floating cans. The purpose of this activity is for students to determine that the…

Sanger, Michael J.

2011-01-01

15

Floating Boats  

ERIC Educational Resources Information Center

The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating

Waugh, Michael

2007-01-01

16

Floating Butterfly  

NSDL National Science Digital Library

In this activity, learners create a cool floating animal using the science of magnetism. Learners discover what happens when a piece of magnetic metal enters a magnet's field. Learners also examine magnetic poles. Note, a drill is required for this activity, and is not included in the cost of materials.

Workshop, Fresno C.

2012-01-01

17

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.

18

"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

19

Towards active microfluidics: Interface turbulence in thin liquid films with floating molecular machines  

NASA Astrophysics Data System (ADS)

Thin liquid films with floating active protein machines are considered. Cyclic mechanical motions within the machines, representing microscopic swimmers, lead to molecular propulsion forces applied to the air-liquid interface. We show that when the rate of energy supply to the machines exceeds a threshold, the flat interface becomes linearly unstable. As a result of this instability, the regime of interface turbulence, characterized by irregular traveling waves and propagating machine clusters, is established. Numerical investigations of this nonlinear regime are performed. Conditions for the experimental observation of the instability are discussed.

Alonso, Sergio; Mikhailov, Alexander S.

2009-06-01

20

Floating Boats  

NSDL National Science Digital Library

The purpose of this article is to describe a simple laboratory activity in which students collect a series of measurements and then use graphical analysis to determine the nature of the relationship between an object's mass and the volume of water it displaces. In this activity, students explore the relationships between the mass of a floating object, the amount the object sinks in the water, and its displaced volume. The data will reveal a unique relationship between an object's metrically measured mass and volume and its buoyancy in water. This can lead to an elaboration of the density concept and provide a concrete model for systems involving other forms of balance and equilibrium.

Waugh, Michael

2007-07-01

21

Active Pulmonary Tuberculosis Case Detection and Treatment Among Floating Population in China: An Effective Pilot  

Microsoft Academic Search

China has more and more floating population because of reform and opening-up. As one of the high burden countries in tuberculosis\\u000a (TB) control in the world, China has to face more challenges about the TB case detection and treatment among floating population\\u000a in China. Aim to evaluate the effect of case detection and treatment of the Floating Population TB Control

Xinxu LiHui; Hui Zhang; Shiwen Jiang; Jia Wang; Xiaoqiu Liu; Weibin Li; Hongyan Yao; Lixia Wang

2010-01-01

22

How much floating light nonaqueous phase liquid can a phreatic surface sustain? Riesenkampf's scheme revisited  

NASA Astrophysics Data System (ADS)

Steady, Darcian, one-phase, phreatic surface flow of groundwater into a horizontal well with a pancake lens of light nonaqueous phase liquid (LNAPL) accumulated in the water table trough is studied by the method of complex analysis. A sharp interface model assumes groundwater capped by two isobaric limbs (groundwater-vadose zone interfaces) of a free surface with an in-between cambered segment of an immiscible LNAPL-water interface, along which pressure is hydrostatically increasing with the depth of the LNAPL "channel." The complex potential polygon is mapped onto an auxiliary half plane where the complex physical coordinate of the flow domain is represented in terms of singular integrals as a solution of the Keldysh-Sedov problem. The shapes of semi-infinite "wings" of the water table contacting the vadose zone gas and of a finite length LNAPL-groundwater interface are found from parametric equations that involve the sink strength and location with respect to the pancake surface, the ordinate of the lowest trough point, and the volume of LNAPL accreted in the lens. Critical conditions, corresponding to the lens contour cusping toward the sink, are found. The Riesenkampf solution contains a free parameter, which is fixed by specifying either a point on the free surface or the volume of the trough-intercepted LNAPL.

Kacimov, Anvar; Obnosov, Yurii; Al-Maktoumi, Ali; Al-Balushi, Mohammed

2011-11-01

23

Does It Sink or Float?  

ERIC Educational Resources Information Center

This activity is designed to teach prekindergarten to second grade students about the concept of sink or float through an inquiry activity. Students will use familiar objects to predict and test the properties of sink and float. Background information is offered to teachers to assist them with this activity. This lesson begins with an engaging…

McDonald, Judith Richards

2012-01-01

24

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

25

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

26

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

27

Floating Head Cup  

NSDL National Science Digital Library

In this activity, learners watch a figure "magically" float up through the air. Learners use 2 straws, a cup, rubber band, pipe cleaner, and piece of buoyant material to make a simple model of novel Chinese art pieces, which are typically made out of ceramics. Use this activity to demonstrate the relationship between density and buoyancy.

Workshop, Watsonville E.

2011-01-01

28

Root Beer Float  

NSDL National Science Digital Library

In this quick activity/demonstration about density, learners examine what happens when two cans of root beer--one diet and one regular--are placed in a large container of water. Do they sink or float? Use this activity to introduce learners to the importance of density as well as the nutritional content of soft drinks.

University, Colorado S.

2009-01-01

29

Bright light activates a trigeminal nociceptive pathway.  

PubMed

Bright light can cause ocular discomfort and/or pain; however, the mechanism linking luminance to trigeminal nerve activity is not known. In this study we identify a novel reflex circuit necessary for bright light to excite nociceptive neurons in superficial laminae of trigeminal subnucleus caudalis (Vc/C1). Vc/C1 neurons encoded light intensity and displayed a long delay (>10s) for activation. Microinjection of lidocaine into the eye or trigeminal root ganglion (TRG) inhibited light responses completely, whereas topical application onto the ocular surface had no effect. These findings indicated that light-evoked Vc/C1 activity was mediated by an intraocular mechanism and transmission through the TRG. Disrupting local vasomotor activity by intraocular microinjection of the vasoconstrictive agents, norepinephrine or phenylephrine, blocked light-evoked neural activity, whereas ocular surface or intra-TRG microinjection of norepinephrine had no effect. Pupillary muscle activity did not contribute since light-evoked responses were not altered by atropine. Microinjection of lidocaine into the superior salivatory nucleus diminished light-evoked Vc/C1 activity and lacrimation suggesting that increased parasympathetic outflow was critical for light-evoked responses. The reflex circuit also required input through accessory visual pathways since both Vc/C1 activity and lacrimation were prevented by local blockade of the olivary pretectal nucleus. These findings support the hypothesis that bright light activates trigeminal nerve activity through an intraocular mechanism driven by a luminance-responsive circuit and increased parasympathetic outflow to the eye. PMID:20206444

Okamoto, Keiichiro; Tashiro, Akimasa; Chang, Zheng; Bereiter, David A

2010-05-01

30

Bright light activates a trigeminal nociceptive pathway  

PubMed Central

Bright light can cause ocular discomfort and/or pain; however, the mechanism linking luminance to trigeminal nerve activity is not known. In this study we identify a novel reflex circuit necessary for bright light to excite nociceptive neurons in superficial laminae of trigeminal subnucleus caudalis (Vc/C1). Vc/C1 neurons encoded light intensity and displayed a long delay (>10 s) for activation. Microinjection of lidocaine into the eye or trigeminal root ganglion (TRG) inhibited light responses completely, whereas topical application onto the ocular surface had no effect. These findings indicated that light-evoked Vc/C1 activity was mediated by an intraocular mechanism and transmission through the TRG. Disrupting local vasomotor activity by intraocular microinjection of the vasoconstrictive agents, norepinephrine or phenylephrine, blocked light-evoked neural activity, whereas ocular surface or intra-TRG microinjection of norepinephrine had no effect. Pupillary muscle activity did not contribute since light-evoked responses were not altered by atropine. Microinjection of lidocaine into the superior salivatory nucleus diminished light-evoked Vc/C1 activity and lacrimation suggesting that increased parasympathetic outflow was critical for light-evoked responses. The reflex circuit also required input through accessory visual pathways since both Vc/C1 activity and lacrimation were prevented by local blockade of the olivary pretectal nucleus. These findings support the hypothesis that bright light activates trigeminal nerve activity through an intraocular mechanism driven by a luminance-responsive circuit and increased parasympathetic outflow to the eye.

Okamoto, Keiichiro; Tashiro, Akimasa; Chang, Zheng; Bereiter, David A.

2010-01-01

31

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

32

Light-Activated Content Release from Liposomes  

PubMed Central

Successful integration of diagnostic and therapeutic actions at the level of individual cells requires new materials that combine biological compatibility with functional versatility. This review focuses on the development of liposome-based functional materials, where payload release is activated by light. Methods of sensitizing liposomes to light have progressed from the use of organic molecular moieties to the use of metallic plasmon resonant structures. This development has facilitated application of near infrared light for activation, which is preferred for its deep penetration and low phototoxicity in biological tissues. Presented mechanisms of light-activated liposomal content release enable precise in vitro manipulation of minute amounts of reagents, but their use in clinical diagnostic and therapeutic applications will require demonstration of safety and efficacy.

Leung, Sarah J.; Romanowski, Marek

2012-01-01

33

Light-activated Reassembly of Split GFP  

PubMed Central

Truncated Green Fluorescent Protein (GFP) with the 11th ?-strand removed is potentially interesting for bioconjugation, imaging, and the preparation of semi-synthetic proteins with novel spectroscopic or functional properties. Surprisingly, the truncated GFP generated by removing the 11th strand, once refolded, does not reassemble with a synthetic peptide corresponding to strand 11, but does reassemble following light activation. The mechanism of this process has been studied in detail by absorption, fluorescence and Raman spectroscopy. The chromophore in this refolded truncated GFP is found to be in the trans configuration. Upon exposure to light a photostationary state is formed between the trans and cis conformations of the chromophore, and only truncated GFP with the cis configuration of the chromophore binds the peptide. A kinetic model describing the light activated reassembly of this split GFP is discussed. This unique light-driven reassembly is potentially useful for controlling protein-protein interactions.

Kent, Kevin P.; Boxer, Steven G.

2011-01-01

34

The Northern Lights: Aurora Activity and Latitude  

NSDL National Science Digital Library

This activity allows students to make and use a geographic plot of aurora location and activity to create their own forecasting relationship for a selected longitude in North America. They will discover that there is a relationship between the appearance of the aurora and the amount of disturbance to Earth's magnetic field and as the magnetic field becomes more disturbed, the Northern Lights will be visible further south from the Arctic region. By measuring these disturbances, they can predict what the latitude of the southern edge of the Northern Lights will be.

Odenwald, Sten

35

MAXI light curves of Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

Monitor of all-sky X-ray Image (MAXI) was designed to be capable of monitoring variability of a medium-sized sample of active galactic nuclei. We examine current reliability of the MAXI light curves. As of October 2010, the light curves of more than forty sky regions of AGN are available at the MAXI web page, http://maxi.riken.jp/. Except for obvious flux changes of bright AGN (for example, those of Mrk 421, the MAXI result of which is presented by Isobe et al. ), individual features of variability in the MAXI light curves of AGN (such as Seyfert galaxies) need careful evaluations. We review effects of data screening and flux evaluation methods on the MAXI light curves.

Ueno, S.; Maxi Team

2010-12-01

36

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

37

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

38

Whatever Floats Your Boat: A Design Challenge  

ERIC Educational Resources Information Center

This article presents a simple design challenge, based on the PBS program "Design Squad's" "Watercraft" activity that will prove engaging to most technology and engineering students. In this floating boat challenge, students are to build a boat that can float and support 25 pennies for at least 10 seconds--without leaking, sinking, or tipping…

Kornoelje, Joanne; Roman, Harry T.

2012-01-01

39

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.

40

Ultra Low-Voltage\\/Low-Power Digital Floating-Gate Circuits  

Microsoft Academic Search

This paper describes a novel technique for implementing ultra low-voltage\\/low-power digital circuits. The effective threshold voltage seen from a control gate is adjusted during a UV-light activated tuning procedure. The optimal effective threshold voltage matching the supply voltage and speed may be programmed by UV-light through an activated conductance between the power-rails and the floating gates. Measured results are provided

Y. Berg; D. t. Wisland; T. s. Lande

1999-01-01

41

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

42

Exploring Floating Concrete and Beam Design.  

ERIC Educational Resources Information Center

Presents two construction activities that address both state and federal science standards and encourage students to consider career options in mathematics and science. Includes floating concrete and paper bridge activities. (YDS)

Snell, Billie G.; Snell, Luke M.

2002-01-01

43

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

44

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.

Baskakov, Ilia V.

2010-01-01

45

What floats a float nurse's boat?  

PubMed

Few studies have examined the personality traits of nurses, and none identified the personality traits of float pool nurses. Float pool nurses have specific personality traits that differ from unit-based nurses. Independence, Tough-Mindedness, Rule Consciousness, Social Boldness, Openness to Change, and Tension were six personality factors that were found to be statistically significantly different. As hospitals implement float pools or resource teams to meet staffing needs, gleaning insight into the specific personality traits of these individuals could assist in nurse recruitment and retention. PMID:21961124

Linzer, Pamela; Tilley, Ann Marie; Williamson, Marlene V

2011-01-01

46

Float It Down the River.  

ERIC Educational Resources Information Center

Presents an activity that involves students in a hands-on, creative project in which they use higher order thinking skills while designing and studying the basics of floating devices. Focuses on inquiry, a number of scientific principles, and the relationship between mathematics and science. (ASK)

Brendzel, Sharon; Orfan, Lucy; Schuhmacher, Robert

2000-01-01

47

Float It Down the River  

NSDL National Science Digital Library

Float it Down the River is an exciting design activity that involves students in a hands-on, creative project in which they use higher order thinking skills in a motivating setting. Students working in groups of four to six are challenged to design and bu

Orfan, Lucy; Schuhmacher, Robert; Brendzel, Sharon

2000-10-01

48

Floating Pumice  

Microsoft Academic Search

REFERRING to a note in the last number of NATURE (p. 532) giving an account of a steamer's having encountered vast quantities of pumice in the Indian Ocean, it may be of interest to record that after passing, in the R.M.S. Quetta, the Straits of Sunda on July 9 last (having sailed close under the then active Krakatoa), we traversed

Henry O. Forbes

1883-01-01

49

Light and immune systems: activation of immunological activities  

NASA Astrophysics Data System (ADS)

Light has been used to treat diseases for hundreds of years. Convenient and powerful light sources such as lasers make photomedicine a major branch in diseases treatment and detection. Originally, light was often used for local treatment, using photomechanical, photochemical, photothermal reactions and photomodulation as the major mechanisms. More and more investigators have become interested in the systemic effects of light, particularly in its effects on immune systems. Much work has been done to activate and/or enhance the host immune system to combat cancer, either using light as a direct tool or as an adjuvant method. Light has long been used for assisting disease detection and diagnosis. Advances in light technology have made photo-diagnostics ever more precise spatially and temporally. Many techniques facilitate observation of bio-molecule interactions and other biological processes at the cellular level, hence providing opportunities to detect and monitor immune activities. This manuscript will review recent photo-immunological research in treatment of cancer. The recent development of combination therapies involving lasers will be presented. Specifically, the results of cancer treatment using laser photothermal interaction, either with or without additional immunological stimulation will be discussed. The immunological effects of photodynamic therapy (PDT), and of its combination with immunotherapy in cancer treatment will also be discussed. Much interest has been recently concentrated in the immunological responses after laser treatment. Such responses at cellular and molecular levels will be discussed. The effect of these treatment modalities on the distant metastases also showed promise of light induced antitumor immunity. The combination therapy and induced immunological responses appear to be the key for long-term control of tumors.

Huang, Zheng; Liu, Hong; Chen, Wei R.

2006-03-01

50

Active Brownian motion tunable by light  

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

51

Floating phenomenon and mode of color appearance  

NASA Astrophysics Data System (ADS)

We found an interesting phenomenon concerning the motion perception and the mode of color appearance. We suppose you are holding a stiff sheet of picture and move it laterally to and fro in front of the eye. Though the picture and all items in it move physically altogether with your hand, your perception is not always so. But when the picture that is a figure appears light-source color mode and a background of object color, a figure appears to slip on a background. We call this a 'floating phenomenon.' We predicted the occurrence of floating phenomenon depends on whether the color is perceived to belong to an object or not. To examine the relation between the floating phenomenon and the mode of color appearance, we measured the luminance threshold of floating phenomenon and the transition luminance between two color modes by constant stimulus method to use a mondrian. Our results show the floating never occurred when the target appeared as object color mode. The floating phenomenon may be caused by the separation of the light-source color from an object or week-belonging.

Aoki, Hironobu; Shinoda, Hiroyuki; Ikeda, Mitsuo

2002-06-01

52

Light-Activated Solid-State Opening Switch.  

National Technical Information Service (NTIS)

Light-activated solid-state opening switches are shown to be a viable approach for switching inductive circuits. Measured photoswitch performance indicates that light-activated opening switches have the power density ratings needed to develop compact indu...

G. I. Kachen J. P. Reilly M. W. Heyse R. A. Petr R. B. Schaefer

1993-01-01

53

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

54

Floating point error analysis  

Microsoft Academic Search

In many floating point calculations it is important to arrange the sequence of calculations such that significant digits are not deleted by intermediate rounding of the numbers. The danger that gross errors may be introduced is always present in floating point calculations, since the number of digits carried in each number is restricted in normal operation by the design of

R. C. Nickerson

1959-01-01

55

Floating islands of Turkey  

Microsoft Academic Search

Turkey abounds in both natural as well as cultural richness. Especially the natural assets located in developing regions have an important role to play in the economic life of such areas. The floating islands are one of these assets and have become an important research subject lately. Turkey is considered as a heaven of floating islands. Almost all geographical regions

Ihsan Bulut

2011-01-01

56

Statistical analysis of the metrological properties of float glass  

NASA Astrophysics Data System (ADS)

The radius of curvature, slope error, surface roughness and associated height distribution and power spectral density of uncoated commercial float glass samples have been measured in our Canadian Light Source Optical Metrology Facility, using our Micromap-570 surface profiler and long trace profilometer. The statistical differences in these parameters have been investigated between the tin and air sides of float glass. The effect of soaking the float glass in sulfuric acid to try to dissolve the tin contamination has also been investigated, and untreated and post-treatment surface roughness measurements compared. We report the results of our studies on these float glass samples.

Yates, Brian W.; Duffy, Alan M.

2008-08-01

57

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

58

Concrete production floating platforms  

SciTech Connect

The floating production platforms operating in the North Sea are adapted from drilling semisubmersibles which allow only a limited payload capacity. Experience of concrete production platforms constructed for the North Sea has led Sea Tank Co. to propose a floating platform which offers large payload and oil storage capacities similar to those of existing fixed platforms. Sea Tank Co. and Institut Francais du Petrole joined forces in early 1976 to study the feasibility of a concrete floating production platform incorporating the structure and the production riser together. The results of this 3-yr program show that the concrete floating structure is economically attractive for permanent utilization on a production site. Furthermore, concrete has definite advantages over other materials, in its long term behavior.

Letourneur, O.; Falcimaigne, J.

1981-01-01

59

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

60

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

61

Floating Squares (GCMP)  

NSDL National Science Digital Library

Floating Squares: this is a resource in the collection "General Chemistry Multimedia Problems". In this problem we will coat a piece of notecard with graphite (from pencil lead). We then will float the piece in two beakers containing water and a second solvent. General Chemistry Multimedia Problems ask students questions about experiments they see presented using videos and images. The questions asked apply concepts from different parts of an introductory course, encouraging students to decompartmentalize the material.

62

50. (no plate) Lens, lens pedestal, mercury float, drawing # ...  

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

50. (no plate) Lens, lens pedestal, mercury float, drawing # 3101, sheet 1 of 2. Approved April 6, 1928. - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

63

51. (no plate) Lens, lens pedestal, mercury float, shade holder ...  

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

51. (no plate) Lens, lens pedestal, mercury float, shade holder installation, drawing # 3101, sheet 2 of 2. Approved April 6, 1928. - Block Island Southeast Light, Spring Street & Mohegan Trail at Mohegan Bluffs, New Shoreham, Washington County, RI

64

Infrared light utilized for photodynamic therapy by activation of rare earth phosphors for visible light generation  

Microsoft Academic Search

Introduction: Photodynamic therapy (PDT) is a treatment for cancer requiring activation of a photosensitizer for light-mediated tumor cytotoxicity. PDT is limited by tissue penetration because visible light is required for photosensitizer activation. SunstonesTM are rare-earth phosphors which up-convert energy from infrared wavelengths to emit higher energy in the visible spectrum. We utilized this unique characteristic to generate light of appropriate

Joshua E. Collins; Thiru V. Lakshman; Jarod E. Finlay; Ajith Kumar; Howard Bell; Ba T. Nguyen; Valery Belov; Jun Luo; Joseph S. Friedberg

2007-01-01

65

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

66

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

67

Light and dark active phosphodiesterase regulation in salamander rods  

PubMed Central

We studied the activation of 3',5'-cyclic guanosine monophosphate (cGMP) phosphodiesterase (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-1-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 microns). Inhibition developed within 50 ms, producing a step decrease of enzyme velocity, which could be offset by activation with flashes or steps of light. The dark PDE activity was equivalent to light activation of enzyme by 1,000 isomerization rod-1s-1, sufficient to hydrolyze the free cGMP pool (1/e) in 0.6 s. Steady light activated PDE in linear proportion to isomerization rate, the range from darkness to current saturation amounting to a 10-fold increase. The conditions for simultaneous onset of inhibitor and illumination to produce no net change of membrane current defined the apparent lifetime of light- activated PDE, TPDE* = 0.9 s, which was independent of both background illumination and current over the range 0-3 x 10(5) isomerization s-1, from 50 to 0 pA. Adaptation was a function of current rather than isomerization: jumps with different proportions of IBMX concentration to steady light intensity produced equal currents, and followed the same course of adaptation in maintained light, despite a 10-fold difference of illumination. Judged from the delay between IBMX- and light-induced currents, the dominant feedback regulatory site comes after PDE on the signal path. The dark active PDE affects the hydrolytic flux and cytoplasmic diffusion of cGMP, as well as the proportional range of the cGMP activity signal in response to light.

1991-01-01

68

Lightly stuffed pyrochlore structure of single-crystalline Yb2Ti2O7 grown by the optical floating zone technique  

NASA Astrophysics Data System (ADS)

Recent neutron scattering and specific heat studies on the pyrochlore Yb2Ti2O7 have revealed variations in its magnetic behavior below 265 mK. In the best samples, a sharp anomaly in the specific heat is observed at T=265 mK. Other samples, especially single crystals, have broad features in the specific heat which vary in sharpness and temperature depending on the sample, indicating that the magnetic ground state may be qualitatively different in such samples. We performed detailed comparisons of the chemical structure of a pulverized single crystal of Yb2Ti2O7, grown by the floating zone technique, to a sintered powder sample of Yb2Ti2O7. Rietveld refinements of neutron powder diffraction data on these samples reveal that the crushed single crystal is best described as a “stuffed” pyrochlore, Yb2(Ti2-xYbx)O7-x/2 with x = 0.046(4), despite perfectly stoichiometric starting material. Substituting magnetic Yb3+ on the nonmagnetic Ti4+ sublattice would introduce random exchange bonds and local lattice deformations. These are expected to be the mechanism leading to the variation of the delicate magnetic ground state of Yb2Ti2O7. Determination of the cubic cell length a could be useful as a method for characterizing the stoichiometry of nonpulverized single crystals at room temperature.

Ross, K. A.; Proffen, Th.; Dabkowska, H. A.; Quilliam, J. A.; Yaraskavitch, L. R.; Kycia, J. B.; Gaulin, B. D.

2012-11-01

69

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-Ph.d. Program

70

Floating nut retention system  

NASA Technical Reports Server (NTRS)

A floating nut retention system includes a nut with a central aperture. An inner retainer plate has an opening which is fixedly aligned with the nut aperture. An outer retainer member is formed of a base plate having an opening and a surface adjacent to a surface of the inner retainer plate. The outer retainer member includes a securing mechanism for retaining the inner retainer plate adjacent to the outer retainer member. The securing mechanism enables the inner retainer plate to float with respect to the outer retainer number, while simultaneously forming a bearing surface for inner retainer plate.

Charles, J. F.; Theakston, H. A. (inventors)

1980-01-01

71

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

72

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

73

Hawaii's Floating City Development Program.  

National Technical Information Service (NTIS)

Progress toward the engineering design, construction logistics, and the construction of large stable floating platforms is described. Plans to construct the first floating city are discussed and the planned utilization of the community described. For the ...

J. P. Craven J. A. Hanson

1972-01-01

74

Measurement of action spectra of light-activated processes.  

PubMed

We report on a new experimental technique suitable for measurement of light-activated processes, such as fluorophore transport. The usefulness of this technique is derived from its capacity to decouple the imaging and activation processes, allowing fluorescent imaging of fluorophore transport at a convenient activation wavelength. We demonstrate the efficiency of this new technique in determination of the action spectrum of the light mediated transport of rhodamine 123 into the parasitic protozoan Giardia duodenalis. PMID:16526885

Ross, Justin A; Zvyagin, Andrei V; Heckenberg, Norman R; Upcroft, Jacqui; Upcroft, Peter; Rubinsztein-Dunlop, Halina

2006-01-01

75

NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 2004  

SciTech Connect

The NSLS remains a viable and productive facility, as can be seen by the rich and diverse science produced in 2004. In one of these exciting research projects published in Nature, researchers detected a rare 'hole crystal' in a cuprate superconductor, which may provide insight into high-temperature superconductivity. In another Nature publication, the crystal structure of a segment of RNA was determined, opening a new window of knowledge into that crucial molecule. These are just a couple of the science highlights of 2004, and many others are displayed in the pages of this report. All told, more than 700 publications resulted from NSLS research this year, the facility hosted 2,299 users, and the number of experiments performed rose from 1,145 in 2003 to 1,374 nuclear indications that the NSLS continues to thrive. As the NSLS accelerator complex enters its third decade of operations, it continues to perform very well. For 2004, the overall reliability of the VUV-IR ring was excellent at 99 percent. The reliability of the x-ray ring was just shy of 92 percent, primarily due to the need to replace the injection septum vacuum chamber, which developed a leak during the middle of the year. The Operations Division did a tremendous job of installing our spare chamber in minimal time, despite the complexity of the job and the inaccessibility of its location in the ring, as well as keeping downtime to a minimum throughout the rest of the year. In order to continue to meet the needs of users, several key beamline upgrades took place this year that will enrich our scientific programs, including upgrades to beamlines U12IR, X1A, X13A, and X21. We are very excited about two brand-new beamlines that were commissioned in 2004: X29 and X27A. X29 is the new mini-gap undulator beamline designed for macromolecular crystallography, and it will meet the growing demand of NSLS users who perform research in that area. The establishment of an x-ray microprobe at beamline X27A, optimized for the environmental science community, is also very important, as it will help to satisfy the large over subscription rate for this technique at the NSLS. Two other important upgrades that were initiated this past year are the replacement of the X25 wiggler with an undulator and the construction of the X9 undulator beamline for small-angle scattering, with an emphasis on nanoscience research. Another key activity that will benefit all users was the restoration of the x-ray ring lattice symmetry, which reduced the horizontal emittance and made the operational lattice more robust. Similarly, all users will benefit from the introduction of the PASS (Proposal Allocation Safety Scheduling) system this past year, which has greatly improved the process of proposal submission, review, allocation, and scheduling. This coming year we will work to add Rapid Access to the capabilities of PASS. Overall, the success of these and the many other projects that space does not permit listing is a testament to the dedication, hard work, and skill of the NSLS staff. Safety has always been an important issue at a large, complex scientific facility like the NSLS and in 2004 it received renewed attention. Safety is our highest priority and we spent a great deal of time reviewing and refining our safety practices and procedures. A new 'Safety Highlights' web page was created for safety news, and a large number of safety meetings and discussions were held. These reviews and meetings generated many ideas on how the NSLS might improve its safety practices, and we are committed to putting these in place and improving our already very good safety program. We had no lost-time accidents in 2004, which is a notable accomplishment. Our goal is to be best in class and I'm confident that by working together we can achieve that status. Several activities took place this past year to advance our proposal to replace the NSLS with a new National Synchrotron Light Source-II facility. These included a major workshop in support of the proposed facility in March, a mail review of our proposal outlinin

MILLER,L.; (EDITOR)

2005-05-01

76

Asset Float and Speculative Bubbles  

Microsoft Academic Search

We model the relationship between asset float (tradeable shares) and speculative bubbles. Investors with heterogeneous beliefs and short-sales constraints trade a stock with limited float because of insider lockups. A bubble arises as price overweighs optimists' beliefs and investors anticipate the option to resell to those with even higher valuations. The bubble's size depends on float as investors anticipate an

HARRISON HONG; JOSÉ SCHEINKMAN; WEI XIONG

2006-01-01

77

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

78

Float Technology Development.  

National Technical Information Service (NTIS)

It is the long-term goal of the principal investigators of this grant to develop profiling floats with expanded capabilities in terms of better sensors, communications methods, greater operating depths, and ice capability. The objective of this work is to...

D. Webb J. Nystuen N. Larson S. C. Riser

2003-01-01

79

Compound floating pivot micromechanisms  

SciTech Connect

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

80

National Synchrotron Light Source 2006 Activity Report.  

National Technical Information Service (NTIS)

An impressive array of highlights is included in this Activity Report to illustrate this extraordinary productivity and its impact to science, technology, and society. For example, one user group investigated new materials for use in lithium-ion batteries...

K. J. Snyder L. M. Miller N. A. Wright S. A. Giordano

2006-01-01

81

Activated Sludge Clarification Using an Advanced DAF Process Based on the Down-Flow Floating Cover Filtration  

Microsoft Academic Search

A novel method for the clarification of activated sludge, using sludge blanket filtration, was proposed. The process was tested continuously with activated sludge over 250days. The proposed process is based on DAF separation, where the mixed liquor is distributed to the surface of the tank, and the clarified effluent is partially recycled with compressed air to the bottom. As a

Ki Yong Lee; Shin Jo Kim; Yong-Woo Lee; Ick Tae Yeom

2011-01-01

82

Conjugated polyelectrolyte capsules: light-activated antimicrobial micro "Roach Motels".  

PubMed

Microcapsules consisting of alternating layers of oppositely charged poly(phenylene ethynylene)-type conjugated polyelectrolytes (CPEs) were prepared via layer-by-layer deposition onto MnCO3 template particles followed by dissolution of the template particles using an ethylenediaminetetraacetate solution. The resulting microcapsules exhibit bright-green fluorescence emission characteristics of the CPEs. Strong antimicrobial activity was observed upon mixing of polyelectrolyte capsules with Cobetia marina or Pseudomonas aeruginosa followed by white-light irradiation. It was demonstrated that the materials act as highly effective light-activated micro "Roach Motels" with greater than 95% kill after exposure to approximately 1 h of white light. PMID:20355752

Corbitt, Thomas S; Sommer, Jonathan R; Chemburu, Sireesha; Ogawa, Katsu; Ista, Linnea K; Lopez, Gabriel P; Whitten, David G; Schanze, Kirk S

2009-01-01

83

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,

84

Ultraviolet Light Induces Epidermal ornithine Decarboxylase Activity  

Microsoft Academic Search

Hairless mice were irradiated with fluorescent sun lamp tubes (peak emission at 313 nm). A significant increase in epidermal ornithine decarboxylase activity was found after 2 hr. A maximum 80-fold increase was found after 24 hr, decreasing again at 48 hr. Epidermal DNA synthesis was decreased at 6 hr and 24 hr increasing to a maximum 48 hr after irradiation.

Nicholas Lowe; Ajit K. Verma; Roswell K. Boutwell

1978-01-01

85

Freely floating smectic films.  

PubMed

We have investigated the dynamics of freely floating smectic bubbles using high-speed optical imaging. Bubbles in the size range from a few hundred micrometers to several centimeters were prepared from collapsing catenoids. They represent ideal model systems for the study of thin-film fluid dynamics under well-controlled conditions. Owing to the internal smectic layer structure, the bubbles combine features of both soap films and vesicles in their unique shape dynamics. From a strongly elongated initial shape after pinch-off, they relax towards the spherical equilibrium, first by a slow redistribution of the smectic layers, and finally by weak, damped shape oscillations. In addition, we describe the rupture of freely floating smectic bubbles, and the formation and stability of smectic filaments. PMID:24692347

May, Kathrin; Harth, Kirsten; Trittel, Torsten; Stannarius, Ralf

2014-05-19

86

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

87

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

88

Hope floats: an orthopaedic tip sheet for float pool nurses.  

PubMed

A common method to address staffing shortages is the use of float nurses. This short-term resolution is not without its issues. When float nurses are unfamiliar with the assigned patient population or when there is little time for unit orientation, unnecessary anxiety and undue stress can affect the staff, healthcare providers, and, most importantly, the patients. Developing creative and informative tools to guide the float nurse during their shift can be beneficial to all involved. PMID:21597351

Roach, Janey A; Tremblay, Lisa M; Carter, Jessica

2011-01-01

89

WindFloat: A floating foundation for offshore wind turbines  

Microsoft Academic Search

This manuscript summarizes the feasibility study conducted for the WindFloat technology. The WindFloat is a three-legged floating foundation for multimegawatt offshore wind turbines. It is designed to accommodate a wind turbine, 5 MW or larger, on one of the columns of the hull with minimal modifications to the nacelle and rotor. Potential redesign of the tower and of the turbine

Dominique Roddier; Christian Cermelli; Alexia Aubault; Alla Weinstein

2010-01-01

90

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

91

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

92

Light-Mode Condensation in Actively-Mode-Locked Lasers  

Microsoft Academic Search

We show that the formation of pulses in actively mode-locked lasers exhibits in certain conditions a transition of the laser mode system to a light pulse state that is similar to Bose-Einstein condensation (BEC). The study is done in the framework of statistical light-mode dynamics with a mapping between the distribution of the laser eigenmodes to the equilibrium statistical physics

Rafi Weill; Baruch Fischer; Omri Gat

2010-01-01

93

Infrared light utilized for photodynamic therapy by activation of rare earth phosphors for visible light generation  

NASA Astrophysics Data System (ADS)

Introduction: Photodynamic therapy (PDT) is a treatment for cancer requiring activation of a photosensitizer for light-mediated tumor cytotoxicity. PDT is limited by tissue penetration because visible light is required for photosensitizer activation. SunstonesTM are rare-earth phosphors which up-convert energy from infrared wavelengths to emit higher energy in the visible spectrum. We utilized this unique characteristic to generate light of appropriate intensity and wavelength for photosensitizer activation and subsequent tumor cell eradication. Methods: SunstonesTM with infrared absorption at 808 and 980nm and visible two-photon emission at 549.9 and 663.1nm were used. A murine NSCLC line was used to determine in vitro toxicity of SunstonesTM and dose response curves for SunstonesTM-mediated PDT. Human NSCLC cells were incubated with/without PhotofrinTM (photosensitizer). Experimental groups included: Infrared light treatment (IR), IR+PhotofrinTM, IR+SunstonesTM, and IR+SunstonesTM+PhotofrinTM. Groups were exposed to 2.5W of 808nm light and assayed for metabolic activity. Results: In vitro toxicity assays showed no significant toxicological side effects after 1 week incubation with SunstonesTM and demonstrated linear response in cytotoxicity as treatment times and infrared dose increased. IR+SunstonesTM+PhotofriTM group showed significantly decreased metabolic activity compared to control cells, cells treated with IR+SunstonesTM, and IR alone. Conclusion: SunstonesTM are nontoxic nanocrystals capable of activating photosensitizers for PDT. Future directions include conjugation of up-converters to a novel photosensitizer and managing the selective uptake of conjugate by tumor cells.

Collins, Joshua E.; Lakshman, Thiru V.; Finlay, Jarod E.; Kumar, Ajith; Bell, Howard; Nguyen, Ba T.; Belov, Valery; Luo, Jun; Friedberg, Joseph S.

2007-02-01

94

Synthetic light-activated molecular switches and motors on surfaces  

NASA Astrophysics Data System (ADS)

Recent advances in synthetic methods and analysis techniques provide a basis for the construction and characterization of organized arrays of molecular switches and motors on surfaces. Among them, molecular systems that can be controlled by light are particularly promising because of their ease of addressability, fast response times and the compatibility of light with a wide range of condensed phases. The aim of this contribution is to highlight selected recent advances in building functional monolayers of light-activated molecules. Special focus is given to monolayers of molecules whose collective switching properties have been harnessed to produce macroscopic effects. The design, structure, and function of monolayers composed of bistable photochromic switches, which can control chirality, wettability, conductivity and self-assembly are described. A recent report on the successful demonstration of light-driven rotary motors functioning while grafted on gold surfaces will also be discussed, followed by a brief conclusion.

Katsonis, Nathalie; Lubomska, Monika; Pollard, Michael M.; Feringa, Ben L.; Rudolf, Petra

95

Genetics Home Reference: Floating-Harbor syndrome  

MedlinePLUS

... PubMed Recent literature OMIM Genetic disorder catalog Conditions > Floating-Harbor syndrome On this page: Description Genetic changes ... names Glossary definitions Reviewed December 2012 What is Floating-Harbor syndrome? Floating-Harbor syndrome is a disorder ...

96

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

97

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

98

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

99

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

100

A floating prolate spheroid.  

PubMed

The equilibrium position of a spherical or prolate spheroidal particle resembling a needle floating at the interface between two immiscible fluids is discussed. A three-dimensional meniscus attached to an a priori unknown contact line at a specified contact angle is established around the particle, imparting to the particle a capillary force due to surface tension that is balanced by the buoyancy force and the particle weight. An accurate numerical solution for a floating sphere is obtained by solving a boundary-value problem, and the results are compared favorably with an approximate solution where the effect of the particle surface curvature is ignored and the elevation of the contact line is computed using an analytical solution for the meniscus attached to an inclined flat plate. The approximate formulation is applied locally around the nearly planar elliptical contact line of a prolate spheroid to derive a nonlinear algebraic equation governing the position of the particle center and the mean elevation of the contact line. The effect of the fluid and particle densities, contact angle, and capillary length is discussed, and the shape of the contact line is reconstructed and displayed from the local solution. PMID:21889165

Pozrikidis, C

2011-12-01

101

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

102

Floating, surface liquids retrieval system  

Microsoft Academic Search

A floating retriever is described for retrieving, for example, spilled oil or other liquid substances on the top of water having a central liquid collection chamber with a vacuum or suction pick-up for delivery of the pollutants to a mother vessel which controls the retriever by means of a boom structure. The retriever has a large surrounding circular float with

1980-01-01

103

Floating roof storage tank boilover  

Microsoft Academic Search

Storage tanks are important facilities for the major hazard installations (MHIs) to store large quantity of crude oil. There is several fire types can occur with large diameter open top floating roof storage tanks. Boilover is considered one of the most dangerous fires in large-scale oil tank. The world has witnessed many incidents due to boilover in floating roof storage

Ibrahim M. Shaluf; Salim A. Abdullah

2011-01-01

104

Code check floating tank roofs  

Microsoft Academic Search

This paper reports that both API 650 and BS 2654 contain criteria for design of single deck pontoon-type tank floating roofs. The codes states that the floating roof shall have sufficient buoyancy to remain afloat under the following conditions: tank content specific gravity is 0.7; the roof center deck is punctured; any two adjacent pontoon compartments are punctured; no water

Hassan

1992-01-01

105

Mirage of Floating Exchange Rates  

Microsoft Academic Search

This note summarizes some of the highlights of my longer paper with Guillermo Calvo”Fear of Floating.” Many emerging market countries have suffered financial crises. One view blames soft pegs for these crises. Adherents to that view suggest that countries move to corner solutions--hard pegs or floating exchange rates. We analyze the behavior of exchange rates, reserves, and interest rates to

Carmen M. Reinhart

2000-01-01

106

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

107

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

108

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

109

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

110

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

111

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

112

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

113

Transient and selective suppression of neural activity with infrared light.  

PubMed

Analysis and control of neural circuitry requires the ability to selectively activate or inhibit neurons. Previous work showed that infrared laser light selectively excited neural activity in endogenous unmyelinated and myelinated axons. However, inhibition of neuronal firing with infrared light was only observed in limited cases, is not well understood and was not precisely controlled. Using an experimentally tractable unmyelinated preparation for detailed investigation and a myelinated preparation for validation, we report that it is possible to selectively and transiently inhibit electrically-initiated axonal activation, as well as to both block or enhance the propagation of action potentials of specific motor neurons. Thus, in addition to previously shown excitation, we demonstrate an optical method of suppressing components of the nervous system with functional spatiotemporal precision. We believe this technique is well-suited for non-invasive investigations of diverse excitable tissues and may ultimately be applied for treating neurological disorders. PMID:24009039

Duke, Austin R; Jenkins, Michael W; Lu, Hui; McManus, Jeffrey M; Chiel, Hillel J; Jansen, E Duco

2013-01-01

114

Transient and selective suppression of neural activity with infrared light  

PubMed Central

Analysis and control of neural circuitry requires the ability to selectively activate or inhibit neurons. Previous work showed that infrared laser light selectively excited neural activity in endogenous unmyelinated and myelinated axons. However, inhibition of neuronal firing with infrared light was only observed in limited cases, is not well understood and was not precisely controlled. Using an experimentally tractable unmyelinated preparation for detailed investigation and a myelinated preparation for validation, we report that it is possible to selectively and transiently inhibit electrically-initiated axonal activation, as well as to both block or enhance the propagation of action potentials of specific motor neurons. Thus, in addition to previously shown excitation, we demonstrate an optical method of suppressing components of the nervous system with functional spatiotemporal precision. We believe this technique is well-suited for non-invasive investigations of diverse excitable tissues and may ultimately be applied for treating neurological disorders.

Duke, Austin R.; Jenkins, Michael W.; Lu, Hui; McManus, Jeffrey M.; Chiel, Hillel J.; Jansen, E. Duco

2013-01-01

115

Vitamin A activates rhodopsin and sensitizes it to ultraviolet light  

PubMed Central

The visual pigment, rhodopsin, consists of opsin protein with 11-cis retinal chromophore, covalently bound. Light activates rhodopsin by isomerizing the chromophore to the all-trans conformation. The activated rhodopsin sets in motion a biochemical cascade that evokes an electrical response by the photoreceptor. All-trans retinal is eventually released from the opsin and reduced to vitamin A. Rod and cone photoreceptors contain vast amounts of rhodopsin, so after exposure to bright light, the concentration of vitamin A can reach relatively high levels within their outer segments. Since a retinal analog, ?-ionone, is capable of activating some types of visual pigments, we tested whether vitamin A might produce a similar effect. In single-cell recordings from isolated dark-adapted salamander green-sensitive rods, exogenously applied vitamin A decreased circulating current and flash sensitivity and accelerated flash response kinetics. These changes resembled those produced by exposure of rods to steady light. Microspectrophotometric measurements showed that vitamin A accumulated in the outer segments and binding of vitamin A to rhodopsin was confirmed in in vitro assays. In addition, vitamin A improved the sensitivity of photoreceptors to ultraviolet (UV) light. Apparently, the energy of a UV photon absorbed by vitamin A transferred by a radiationless process to the 11-cis retinal chromophore of rhodopsin, which subsequently isomerized. Therefore, our results suggest that vitamin A binds to rhodopsin at an allosteric binding site distinct from the chromophore binding pocket for 11-cis retinal to activate the rhodopsin, and that it serves as a sensitizing chromophore for UV light.

Miyazono, Sadaharu; Isayama, Tomoki; Delori, Francois C.; Makino, Clint L.

2013-01-01

116

Quality Control and Application of Oxygen Data from Profiling Floats  

NASA Astrophysics Data System (ADS)

Profiling floats provide a near-ideal platform for monitoring the seasonal evolution of both physical and chemical processes at the regional, basin, and global scale. Although temperature, salinity, and pressure data must pass well-defined Quality Control protocols at Global Data Assembly Centers, no such protocol exists for chemical data (oxygen and nitrate) now being measured on 348 “Argo Equivalents” (of which ~150 are still active) within the ~3200 float array. With the number of chemical measurements returned from the Argo array rapidly growing, it is important to develop and evaluate new QC procedures for these data in order to use the chemical Argo dataset for quantitative descriptions of oceanic biogeochemical processes. We initiated a preliminary assessment of quality control protocols for profiling float data, with the ultimate goal of using the QC'd dataset for biogeochemical studies, including use of float oxygen data to constrain a model that calculates rates of Net Community Production. Profiling float oxygen data prior to June 2010 were compared to the World Ocean Atlas 2009 monthly climatology. Large deviations from the climatology were observed for many floats, indicating the need for a QC protocol for float oxygen data, and possibly also indicating real processes not accounted for in the climatology. Approximately 100 floats were selected to calculate net community production in the euphotic zone. Here we discuss different QC methods that we have explored, and evaluate how each method affects the calculated NCP rates. Depending on which QC method is used, the sign of the NCP rates can change, thus further highlighting the importance of establishing a proper QC protocol for float oxygen data.

Takeshita, Y.; Martz, T. R.; Johnson, K. S.; Plant, J.; Riser, S.; Gilbert, D.

2010-12-01

117

Floating Silicon Method  

SciTech Connect

The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.

Kellerman, Peter

2013-12-21

118

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

119

Preparation and characterization of Cobalt Sulfophthalocyanine/TiO 2/fly-ash cenospheres photocatalyst and study on degradation activity under visible light  

NASA Astrophysics Data System (ADS)

Cobalt Sulfophthalocyanine (CoSPc) sensitized TiO 2 sol samples were prepared through a Sol-Gel method using Cobalt Sulfophthalocyanine as a sensitizer. Loading and modified floating photocatalyst was prepared by hydrothermal method using fly-ash cenospheres as a carrier. The properties of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) and UV-vis diffuse reflectance spectrum (DRS). Photocatalytic activity was studied by degrading wastewater of methylene blue under visible light. The results indicate that the fly-ash cenospheres are covered by modified TiO 2 film which composed of the anatase, brookite and rutile misch crystal phase. CoSPc/TiO 2/fly-ash cenospheres samples have good catalytic activity under visible light, and have strong absorbency during 600-700 nm. The sensitization of CoSPc can enhance visible light catalytic activity of TiO 2/fly-ash cenospheres. The degradation rate of methylene blue reaches 73.36% in 180 min under the visible light illumination. But too much CoSPc can decrease its catalytic activity.

Huo, Pengwei; Yan, Yongsheng; Li, Songtian; Li, Huaming; Huang, Weihong

2009-05-01

120

Temperature rise during experimental light-activated bleaching.  

PubMed

The purpose of this study was to evaluate the surface and intrapulpal temperatures after treatments with different bleaching gels subjected to different types of light activation. A K-type thermocouple and infrared thermometer were used to measure the temperature increase during the 15- or 30-min treatment period. Light-emitting diode with a center wavelength of 405 nm (LED405), organic light-emitting diode (OLED), and femtosecond laser were tested and compared to ZOOM2. The tooth surface was treated with five bleaching agents and Vaseline which served as a control.The generalized estimating equation (GEE) model was applied for testing the differences in temperature increase. The ZOOM2 light source led to the largest increase in mean pulpal and tooth surface temperatures of 21.1 and 22.8 °C, followed by focused femtosecond laser which increased the pulpal and surface temperatures by up to 15.7 and 16.8 °C. Treatments with unfocused femtosecond laser, LED405, and OLED induced significantly lower mean temperature increases (p?light activation, while LED405, OLED, and unfocused femtosecond laser could be safely used. PMID:23780710

Klaric, Eva; Rakic, Mario; Sever, Ivan; Tarle, Zrinka

2013-06-19

121

Extra-strong "floating nut"  

NASA Technical Reports Server (NTRS)

Increased bearing area withstands much higher torque than previous designs. Floating nut makes it possible to fasten parts on heavy-duty equipment, such as tractors and cranes, even though they can be reached for tightening from one side only.

Charles, J. F.; Theakston, H.

1979-01-01

122

Code check floating tank roofs  

SciTech Connect

This paper reports that both API 650 and BS 2654 contain criteria for design of single deck pontoon-type tank floating roofs. The codes states that the floating roof shall have sufficient buoyancy to remain afloat under the following conditions: tank content specific gravity is 0.7; the roof center deck is punctured; any two adjacent pontoon compartments are punctured; no water or live loads are present; and the roof primary drain is inoperative.

Hassan, H.M.K. (Abu Dhabi Marine Operating Co. (United Arab Emirates))

1992-10-01

123

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

124

Skylab floating ice experiment  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Coupling of the aircraft data with the ground truth observations proved to be highly successful with interesting results being obtained with IR and SLAR passive microwave techniques, and standard photography. Of particular interest were the results of the PMIS system which operated at 10.69 GHz with both vertical and horizontal polarizations. This was the first time that dual polarized images were obtained from floating ice. In both sea and lake ice, it was possible to distinguish a wide variety of thin ice types because of their large differences in brightness temperatures. It was found that the higher brightness temperature was invariably obtained in the vertically polarized mode, and as the age of the ice increases the brightness temperature increases in both polarizations. Associated with this change in age, the difference in temperature was observed as the different polarizations decreased. It appears that the horizontally polarized data is the most sensitive to variations in ice type for both fresh water and sea ice. The study also showed the great amount of information on ice surface roughness and deformation patterns that can be obtained from X-band SLAR observations.

Campbell, W. J. (principal investigator); Ramseier, R. O.; Weaver, R. J.; Weeks, W. F.

1975-01-01

125

Floating biological contactor  

SciTech Connect

A method is described using biological microorganisms for removing selected biodegradable materials from a pond or similar body of water, comprising the steps of: analyzing a sample of said pond water to determine at least one type of microorganism appropriate for feeding on said selected materials; fixing a plurality of bio-suspension elements within an enclosure which is floating at least partially submerged in said water body, said elements providing surfaces for supporting the growth of films of biological microorganisms; introducing said appropriate microorganisms into said enclosure along with discrete amounts of said pond water for growing colonies of said appropriate microorganisms on said biosuspension elements while circulation or other motion of said pond water is minimized in said enclosure; sampling, testing, and analyzing the water and microorganisms in said enclosure, and nurturing the growth of said microorganisms until large and stable colonies of said microorganisms have been established on said bio-suspension elements; and, thereafter, circulating pond water gently and regularly through and around said stable colony of appropriate microorganisms in said enclosure and returning said circulated water to the pond.

DiClemente, L.M.; Pickering, J.W. Wansea, R.M.

1993-07-20

126

Floating Tip Nanolithography  

NASA Astrophysics Data System (ADS)

We introduce a new mode of operation to standard atomic force microscopes, working under ambient conditions, for truly noncontact nanolithography. A phase-locked loop, based on tiny oscillations (<1 nm) of the cantilever at a frequency far from its mechanical resonance, is used to maintain the gap between the tip and the sample at a predetermined value of 1 - 4 nanometers continuously for long times without the tip ever touching the surface. In a geometry characteristic for Apertureless Scanning Near Field Optical Microscope, the tip is illuminated by a focused beam of a femtosecond laser (800 nm, 20 fsec, 100 mw ) for nano-patterning of the area under the tip. Under the laser irradiation the tip apex heats to a few hunderd degrees as verified by a direct measurement of Raman line shifts, and the elecrtomagnetic enhancement under the tip is used when the laser irradiates the actual tip apex. We demonstrate Floating Tip Nanolithography of two different types, both with lateral resolution of 10-20 nm. With a hot tip (the laser is not in contact with the surface) we thermally pattern the surface of a polymer film, and based on the electromagnetic field enhancement under the sharp tip we ablate narrow lines on a gold film. Future applications will be discussed.

Prior, Yehiam; Zhang, Kaiyin; Milner, Alexander; Karpovski, Michael

2008-03-01

127

Glucocorticoid receptor activity regulates light adaptation in the zebrafish retina  

PubMed Central

Glucocorticoids modulate diverse aspects of physiology and behavior, including energy homeostasis, stress response, and memory, through activation of the glucocorticoid receptor (GR). Light perception has profound effects on the production of glucocorticoids via functional connections of the retina to the hypothalamus-pituitary-adrenal axis. We report here that glucocorticoids can also signal in the reverse direction, i. e., regulate visual function in zebrafish, Danio rerio. The zebrafish GR mutant, grs357, harbors a missense mutation that completely blocks the transcriptional activity of GR. In this mutant, visual behavior was abolished following a period of darkness and recovered sluggishly after return to the light. Electrophysiological measurements showed that the photoresponse of the dark-adapted retina was reduced in the mutant and re-adapted to light with a substantial delay. Several gene products, including some that are important for dopaminergic signaling, were misregulated in grs357 mutants. We suggest that GR controls a gene network required for visual adaptation in the zebrafish retina and potentially integrates neuroendocrine and sensory responses to environmental changes.

Muto, Akira; Taylor, Michael R.; Suzawa, Miyuki; Korenbrot, Juan I.; Baier, Herwig

2013-01-01

128

Light scattering and absorption caused by bacterial activity in water.  

PubMed

There is a growing class of elementary particle detectors, large-water ?erenkov detectors, that have a body of water (thousands of tons) as a sensitive medium. Particles are detected when they interact with the water and produce ?erenkov light, so detection efficiency relies on the transparency of the water. These detectors are active typically for many years, so biological activity (primarily bacterial growth) is one of the means by which the transparency of the water may be reduced. We present the results of a measurement of light scattering and absorption from a population of Escherichia coli in water, which is used as a model for bacteria in general. One can separate the scattering and absorption by varying the refractive index of the medium by using a solute of high molecular weight. We show that the results can be understood simply in terms of light scattering from small spheres (radius ? wavelength) with an effective refractive index, n(b), plus a small amount of absorption in the ultraviolet. We compare his scattering with Rayleigh scattering in pure water. PMID:20941320

Waltham, C; Boyle, J; Ramey, B; Smit, J

1994-11-01

129

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.

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

2012-01-01

130

Lighting.  

SciTech Connect

Since lighting accounts for about one-third of the energy used in commercial buildings, there is opportunity to conserve. There are two ways to reduce lighting energy use: modify lighting systems so that they used less electricity and/or reduce the number of hours the lights are used. This booklet presents a number of ways to do both. Topics covered include: reassessing lighting levels, reducing lighting levels, increasing bulb & fixture efficiency, using controls to regulate lighting, and taking advantage of daylight.

United States. Bonneville Power Administration.

1992-09-01

131

Simultaneous removal of particles and dissolved organic matter in floating media filter for surface water treatment  

Microsoft Academic Search

This research investigated the performance of floating media filter in removing particles and dissolved organic matter from surface water. Pilot-scale study consists of floating plastic media pre-filter connected with either granular activated carbon (GAC) or sponge biological filter (BF) bed. In the floating plastic media filter, coagulation and flocculation processes using poly-aluminum chloride (PACl) as coagulant at an optimum dose

C. Chiemchaisri; S. Passananon; H. H. Ngo; S. Vigneswaran

2009-01-01

132

Design, Synthesis, and Monitoring of Light-Activated Motorized Nanomachines  

NASA Astrophysics Data System (ADS)

Our group has developed a family of single molecules termed nanocars, which are aimed at performing controllable motion on surfaces. In this work, a series of light-activated motorized nanomachines incorporated with a MHz frequency light-activated unidirectional rotary motor were designed and synthesized. We hope the light-activated motor can serve as the powering unit for the nanomachines, and perform controllable translational motion on surfaces or in solution. A series of motorized nanovehicles intended for scanning tunneling microscopy (STM) imaging were designed and synthesized. A p-carborane-wheeled motorized nanocar was synthesized and monitored by STM. Single-molecule imaging was accomplished on a Cu(111) surface. However, further manipulations did lead to motor induced lateral motion. We attributed this result to the strong molecule-surface interactions between the p-carborane-wheeled nanocar and the Cu(111) surface and possible energy transfer between the rotary motor and the Cu(111) surface. To fine-tune the molecule-surface interactions, an adamantane-wheeled motorized nanocar and a three-wheel nanoroadster were designed and synthesized. In addition, the STM substrates will be varied and different combinations of molecule-surface interactions will be studied. As a complimentary imaging method to STM, single-molecule fluorescence microscopy (SMFM) also provides single-molecule level resolution. Unlike STM experiment requires ultra-high vacuum and conductive substrate, SMFM experiment is conducted at ambient conditions and uses non-conductive substrate. This imaging method allows us to study another category of molecule-surface interactions. We plan to design a fluorescent motorized nanocar that is suitable for SMFM studies. However, both the motor and fluorophore are photochemically active molecules. In proximity, some undesired energy transfer or interference could occur. A cyanine 5- (cy5-) tagged motorized nanocar incorporated with the MHz motor was designed and synthesized in order to minimize the potential energy transfer or interference between the motor and the fluorophore. The SMFM study of this cy5-tagged motorized nanocar is currently undergoing. The design of light-activated motorized nanocar inspired the design of nanosubmarines. We used fluorescence quenching and fluorescence correlation spectroscopy (FCS) to study the diffusion of single molecules. The fluorescence quenching experiments of Ru(bpy)3+2 by a quenching nanosubmarine was conducted, but no motor induced acceleration of the molecule were observed. Another fluorescent nanosubmarine was monitored by FCS, and no increase of diffusion coefficient was found. Finally, a 1-D channel approach was adopted for decreasing the effects of Brownian motion, and acceleration of nanosubmarine was observed.

Chiang, Pinn-Tsong

133

A Spinel Oxynitride with Visible-Light Photocatalytic Activity  

SciTech Connect

Spinel zinc gallium oxynitride photocatalysts are prepared by the sol-gel method, at 550 C. In these materials, of base composition ZnGa{sub 2}O{sub 4} (octahedral Ga), reaction with ammonia leads to ZnGa{sub 2}O{sub x}N{sub y}, with a dramatic reduction of the bandgap to 2.7 eV, with just 1.3% N and no loss of Zn. At 850 C this phase is converted into wurzite (tetrahedral Ga). The novel oxynitrides also show visible-light photocatalytic activity towards the degradation of methylene blue.

Boppana, V.; Doren, D; Lobo, R

2010-01-01

134

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

135

Antimicrobial properties of light-activated polyurethane containing indocyanine green.  

PubMed

The aim of this study was to produce novel antimicrobial polymers containing the light-activated antimicrobial agent indocyanine green (ICG). The novel materials were prepared by swelling polyurethane in acetone containing water and ICG, followed by solvent evaporation. The uptake of ICG was dependent upon the ratio of acetone to water. Only at a ratio of 99 parts acetone to 1 part water was there any substantial colouration of the samples. When exposed to laser light from the near infrared spectrum (808 nm), polyurethane-containing ICG exhibited antimicrobial activity against Gram-positive bacteria; a 2 log?? reduction was achieved against methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis after 15 min exposure, corresponding to an energy dose of 31.83 J delivered at an energy density of 31.83 J/cm². Under the same conditions, Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) appeared to be less susceptible, the viable count being reduced by 0.5 log??. Some of the physical properties of the resulting material were also investigated and it was found that the elasticity (Young's modulus) was reduced by approximately 60%. Furthermore, when the ICG-containing polymer was stretched, the breaking point occurred when the elongation was 6.7 times the initial value, while ICG-free polyurethane samples did not break following a 7-fold elongation. The contact angles for water droplets revealed that the ICG-containing polymer was more hydrophobic than untreated polyurethane. The results of this study show that ICG can be embedded in polyurethane to produce materials which when irradiated with near-infrared light can exert a bactericidal effect particularly against MRSA and S. epidermidis. Such materials may be useful for preparing intravenous catheters, which are often colonized by such organisms. PMID:20008087

Perni, Stefano; Pratten, Jonathan; Wilson, Michael; Piccirillo, Clara; Parkin, Ivan P; Prokopovich, Polina

2011-01-01

136

Floating, surface liquids retrieval system  

SciTech Connect

A floating retriever is disclosed for retrieving, for example, spilled oil or other liquid substances on the top of water having a central liquid collection chamber with a vacuum or suction pick-up for delivery of the pollutants to, for example, a mother vessel which controls the retriever by means of, for example, a boom structure. The retriever has a large surrounding circular float with intake ports with rotational, wiper/configured, laterally disposed vaned cylinders to bring the retrieved liquid to the collection chamber. The device includes an inverted-dome, variable level, water well for stability, as well as radially positioned, selectively controlled, out-rigger, floating screws which may turn clockwise or counter-clockwise for both drawing the oil to the intake ports and providing for propulsion and guidance. In an alternate embodiment, an initial, gravity oil/water separator is included in the retriever in association with the central collection chamber.

Gordon, E.T.

1983-07-05

137

Why Do Countries Float the Way They Float?  

Microsoft Academic Search

Countries that are classified as having floating exchange rate systems (or very wide bands) show strikingly different patterns of behavior. They hold very different levels of international reserves and allow very different volatilities in the movements of the exchange rate relative to the volatility that they tolerate either on the level of reserves or in interest rates. We document these

Ricardo Hausmann; Ugo G. Panizza; Ernesto Hugo Stein

2000-01-01

138

Why do countries float the way they float?  

Microsoft Academic Search

Countries that are classified as having floating exchange rate systems (or very wide bands) show strikingly different patterns of behavior. They hold very different levels of international reserves and allow very different volatilities to the movements of the exchange rate relative to the volatility that they tolerate either on the level of reserves or on interest rates. We document these

Ricardo Hausmann; Ugo Panizza; Ernesto Stein

2001-01-01

139

Strength tests on hulls and floats  

NASA Technical Reports Server (NTRS)

The present report deals with strength tests on hulls and floats intended in part for the collection of construction data for the design of these components and in part for the stress analysis of the finished hulls and floats.

Matthaes, K

1942-01-01

140

Dynamics of a Floating Ice Sheet.  

National Technical Information Service (NTIS)

Civilian and military operations are frequently conducted on the surface of floating ice sheets. For reasons of safety and operational reliability it is often required to predict the deformation and stresses in such floating ice plates due to surface load...

H. Reismann Y. C. Lee

1968-01-01

141

Modeling International Space Station (ISS) Floating Potentials.  

National Technical Information Service (NTIS)

The floating potential of the International Space Station (ISS) as a function of the electron current collection of its high voltage solar array panels is derived analytically. Based on Floating Potential Probe (FPP) measurements of the ISS potential and ...

D. C. Ferguson B. Gardner

2002-01-01

142

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

143

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

144

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false External floating roof converted into an internal floating roof. 65.45 Section 65.45 Protection...RULE Storage Vessels § 65.45 External floating roof converted into an internal floating...

2013-07-01

145

Optics: Light, Color, and Their Uses. An Educator's Guide with Activities in Science and Mathematics.  

ERIC Educational Resources Information Center

This educator's guide from discusses optics, light, color and their uses. Activities include: (1) "Reflection of Light with a Plane (Flat) Mirror--Trace a Star"; (2) "Reflection of Light with Two Plane Mirrors--Double Mirrors Placed at a 90-Degree Angle"; (3) "Reflection of Light with Two Plane Mirrors--Double Mirrors Placed at a Number of…

National Aeronautics and Space Administration, Huntsville, AL. George C. Marshall Space Flight Center.

146

Airship-floated wind turbine  

SciTech Connect

A wind turbine, by use of a tethered airship for support, may be designed for the economical recovery of power at heights of 2,000 feet or more above ground, at which height power density in the wind is typically three times the power density available to a conventionally supported wind turbine. Means can be added to such an airship-floated wind turbine which will permit its generators to be used to meet load demand even during periods of little or no wind. Described to this end is a wind turbine system which combines, among other novel features: a novel tether line system which provides access for men and materials to the supporting airship while in active service, a novel system for providing additional buoyant lift at the nose of the turbine-supporting airship to offset the vertical component of tension induced in the tether line by the downwind force exerted by the turbine blades, a novel bearing assembly at the nose of the supporting airship which permits the airship to rotate as a unit with the turbine it supports without causing a similar rotation of the tether line, a novel turbine airship structure which handles concentrated loads from the turbine efficiently and also permits the safe use of hydrogen for buoyancy, a novel ''space frame'' structure which supports the turbine blades and greatly reduces blade weight, a novel system for controlling turbine blade angle of incidence and for varying blade incidene in synchrony with blade angular position abut the turbine axis to provide greater control over airship movement, a novel system for locating propellor-driven generators out at the wind turbine perimeter and for using lightweight, high-RPM generators to produce electrical energy at a power line frequency, which greatly reduces the weight required to convert turbine blade torque into useful power, and a novel system for incorporating compressed air storage and combustion turbine components into the wind turbine's generator drive systems.

Watson, W. K.

1985-01-01

147

Float charging of valve-regulated lead-acid batteries: A balancing act between secondary reactions  

Microsoft Academic Search

The behavior of valve-regulated lead-acid batteries on float charging is influenced by many interacting parameters. A mathematical model has been developed that describes the effects of kinetic cell parameters, float voltage (or current), and temperature on electrode potentials and rates of electrode reactions. The considered reactions are: hydrogen evolution, oxygen evolution, oxygen reduction, grid corrosion, and discharge of active material

D. Berndt; U. Teutsch

1996-01-01

148

Optimization of float use in risk analysis-based network scheduling  

Microsoft Academic Search

Floats are often used in project networks for resource allocations and as an alternative for reducing project costs without causing negative impact on project duration. However, when the time uncertainties of non-critical activities are great, the use of floats can lead to an increased risk of project schedule overruns, and accordingly an increase in project costs. This paper presents a

Daji Gong

1997-01-01

149

Impact of floating population on the epidemic of tuberculosis: a spatial analysis  

Microsoft Academic Search

According to the report issued by the Health Bureau of Beijing that the number of newly registered active pulmonary tuberculosis cases in floating population exceeded half of that in registered permanent residence in 2006. More attention has been paid to the tuberculosis of floating population. Materials and methods: The population data included in the studied was reported by the Beijing

Zhongwei Jia; Xiaoxin He; Wenjuan Zhao; Yansheng An; Wuchun Cao; Xiaowen Li

2007-01-01

150

Light-polarization tunneling in optically active media  

NASA Astrophysics Data System (ADS)

Evolution of the polarization state of light transmitted through an optically active medium follows from the Maxwell theory of electromagnetism. The theory can be reduced to the study of a Schrödinger-like equation for two levels representing the right- and left-circular polarizations, respectively. Using quantum mechanical techniques, we show that the Stokes parameters should exhibit tunneling in the anisotropic nonlinear medium—a phenomenon similar to quantum tunneling—provided the nonlinear parameter be large enough. In order to recover the quantum results in the classical framework, one has to consider additional fluctuations of the initial parameters, since the classical problem has no fundamental fluctuations. Indeed, even for small fluctuations, the polarization state may exhibit chaotic tunneling across classically forbidden regions. This is exemplified through polarization tunneling in a nonlinear transparent medium submitted to constant Kerr effect and modulated nonlinear parameter.

Botet, Robert; Kuratsuji, Hiroshi

2008-01-01

151

32 CFR 935.165 - Floating objects.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Floating objects. 935.165 Section 935...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...

2013-07-01

152

Floating, surface liquids retrieval system  

Microsoft Academic Search

A floating retriever is disclosed for retrieving, for example, spilled oil or other liquid substances on the top of water having a central liquid collection chamber with a vacuum or suction pick-up for delivery of the pollutants to, for example, a mother vessel which controls the retriever by means of, for example, a boom structure. The retriever has a large

1983-01-01

153

Floating-roof tank evaporation  

SciTech Connect

The book describes an improved method for estimating the total evaporative losses of the equivalent atmospheric hydrocarbon emissions from external floating-roof tanks that contain multicomponent hydrocarbon mixtures (such as gasolines and crude oils) or single-component stocks (such as petro-chemicals).

Not Available

1989-01-01

154

Floating support for older people  

Microsoft Academic Search

The introduction of ‘floating support’ - a tenure neutral service - in many local authorities is causing much consternation among tenants because the scheme manager they thought would always be there is leaving. Yet, with an ageing population combined with increasingly finite resources, how can services provide support to those who need it most and to what degree should sheltered

Tony Cousins; Phil Saunders

2008-01-01

155

Floating Ring-Groove Lapper  

NASA Technical Reports Server (NTRS)

Tool fits out-of-round seal groove and laps it to fine finish without binding. Includes floating lapping pieces riding freely in groove, and are curved to match nominal diameter of groove. One lapping piece tightened so it does not move relative to disk.

Williams, Robert L., Sr.; Williams, Robert L., Jr.; Chase, Timothy L.

1992-01-01

156

Mathematical Modeling of Floating Ice  

NASA Astrophysics Data System (ADS)

A significant fraction of the surface of the global ocean is covered by floating ice, the presence of which has profound influences on the state of the global climate system. The floating ice appears both in the form of sea-ice, created in situ over the open ocean, and in the form of ice shelves, the result of land ice sheets draining into the ocean. Ice is arguably one of the most complex fluids in the climate system, both from a dynamical and thermodynamical point of view. The former because of its inherently non-linear rheology and the later because of the ice-albedo feedback mechanism. Added to these complexities, the mathematical and computational modeling of floating has the pragmatic difficulty of properly treating phenomena that occur both on sub-grid scales and disparate time scales. Examples of sub-grid scale phenomena include the treatment of sea-ice thickness distributions and the effects of ocean geostrophic turbulence on the sea ice. This talk presents an overview of the role of floating ice in the climate system, some of the outstanding theoretical challenges, and the role in which modern applied mathematics may play in the future development of the field.

Holland, D. M.

2001-05-01

157

Airship-floated wind turbine  

Microsoft Academic Search

A wind turbine, by use of a tethered airship for support, may be designed for the economical recovery of power at heights of 2,000 feet or more above ground, at which height power density in the wind is typically three times the power density available to a conventionally supported wind turbine. Means can be added to such an airship-floated wind

1985-01-01

158

Some Activities with Polarized Light from a Laptop LCD Screen  

ERIC Educational Resources Information Center

The LCD screen of a laptop computer provides a broad, bright, and extended source of polarized light. A number of demonstrations on the properties of polarized light from a laptop computer screens are presented here.

Fakhruddin, Hasan

2008-01-01

159

Phytoremediation of perchlorate by free floating macrophytes.  

PubMed

Phytoremediation of perchlorate by free floating macrophytes (Eichornia, Pistia, Salvinia and Lemna) was evaluated in this study. Among the plants tested, Pistia showed 63.8 ± 4% (w/v) removal of 5 mg/L level perchlorate in 7 days, whereas the removal was absent in other plants. Phyto-accumulation (18.2%) and rhizo-degradation (45.68%) were identified as the mechanisms involved in perchlorate removal in Pistia. Whole plant extraction yielded 45.4 ?g perchlorate/g dry weight biomass in 7 days period. High intensity of light and presence of nitrate negatively affected perchlorate removal by Pistia. An enrichment of Pistia root homogenate exhibited faster reduction of perchlorate where 100mg/L of the compound was reduced completely in 48 h under anoxic condition. A novel perchlorate reducing bacterium, isolated from Pistia root homogenate enrichment was identified as Acinetobacter sp. NIIST (Genbank JX467695). PMID:23872336

Bhaskaran, Krishnakumar; Vijaya Nadaraja, Anupama; Tumbath, Soumya; Babu Shah, Liji; Gangadharan Puthiya Veetil, Prajeesh

2013-09-15

160

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

161

Sinking and Floating Water  

NSDL National Science Digital Library

This activity is a classroom lab where students learn that cold water is denser and hot water is less dense than room temperature water. Students perform an experiment and relate to their background knowledge to make conjectures.

Thill, Nancy

162

Floating and Falling Flows  

NSDL National Science Digital Library

Learners create beautiful fluid motion. They explore fluid dynamics, surface tension, solubility, and buoyancy while mixing liquids together. Learners can photograph or film the fluid motion for analysis as well. This activity is also suitable as a demonstration. Learners can continue their investigations by completing the related activity "Density Rainbow and the Great Viscosity Race." Resource contains vocabulary definitions, detailed background information, and suggestions for assessment and extensions.

Taylor, Cody; Camacho, Gala; Hertzberg, Jean; Zarske, Malinda S.; Carlson, Denise

2006-01-01

163

Programmable Floating Gate FPAA Switches Are Not Dead Weight  

Microsoft Academic Search

In most reconfigurable systems, such as FPAAs and FPGAs, the switch element and its associated memory cell is a necessary overhead for performing computation with the active components. However, floating gate based switches in large-scale FPAAs can be programmed anywhere between simple \\

Christopher M. Twigg; Jordan D. Gray; Paul E. Hasler

2007-01-01

164

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

165

Accelerating Microblaze Floating Point Operations  

Microsoft Academic Search

The MicroBlaze processor serves in many FPGA designs as the central 32 bit CPU with access to the global off chip memory and peripherals. MicroBlaze provides FSL links for up to 8 coprocessors. We present two MicroBlaze designs. The first design works with 8 PicoBlaze-based accelerators for pipelined, single-precision floating point vector-oriented operations, and delivers over 1.2 GFLOPs. The second

Jiri Kadlec; Roman Bartosinski; Martin Danek

2007-01-01

166

Decimal Floating-Point Multiplication  

Microsoft Academic Search

Decimal multiplication is important in many com- mercial applications including financial analysis, banking, tax calculation, currency conversion, insurance, and accounting. This paper presents the design of two decimal floating-point multipli- ers; one whose partial product accumulation strategy employs decimal carry-save addition, and one which employs binary carry-save addition. The multiplier based on decimal carry- save addition favors a non-pipelined, iterative

Mark A. Erle; Brian J. Hickmann; Michael J. Schulte

2009-01-01

167

NADP regulates the light activation of NADP-dependent malate dehydrogenase  

Microsoft Academic Search

The chloroplastic NADP-dependent malate-dehydrogenase (EC 1.1.1.82) activity is modulated by light and dark. The enzyme is activated upon illumination of intact or broken chloroplasts or by incubation with dithiothreitol, whereas dark has the opposite effect. The present communication shows an additional regulation of the light modulation: in isolated intact pea chloroplasts, light activation was inhibited in the presence of electron

R. Scheibe; J.-P. Jacquot

1983-01-01

168

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

169

UV light induced plasticization and light activated shape memory of spiropyran doped ethylene-vinyl acetate copolymers.  

PubMed

Light activated shape memory polymers (LASMPs) are relatively new kinds of smart materials and have significant technological applications ranging from biomedical devices to aerospace technology. EVA films doped with spiropyran with contents ranging from 0.1% to 3% show efficient UV activated shape memory behaviors if the fixed shape deformation is limited within 80%. For EVA films containing 3% spiropyran, UV irradiation causes a decrease in EVA modulus of about 44%. FT-IR and solid (13)C NMR in association with UV-vis absorption analysis demonstrate that UV irradiation transforms spiropyran from the SP form to the MC form, meanwhile, it induces an increase in the molecular mobility in the amorphous phase of EVA. Thus, the spiropyran-doped EVA films act as LASMPs via a mechanism of light induced plasticization. Light activated spiropyran acts as a plasticizer to EVA. PMID:24686814

Zhang, Xianzhe; Zhou, Qingqing; Liu, Huarong; Liu, Hewen

2014-06-01

170

Temporal and spatial distribution of floating objects in coastal waters of central-southern Chile and Patagonian fjords  

NASA Astrophysics Data System (ADS)

Floating objects are suggested to be the principal vector for the transport and dispersal of marine invertebrates with direct development as well as catalysts for carbon and nutrient recycling in accumulation areas. The first step in identifying the ecological relevance of floating objects in a specific area is to identify their spatio-temporal distribution. We evaluated the composition, abundance, distribution, and temporal variability of floating objects along the continental coast of central-southern Chile (33-42°S) and the Patagonian fjords (42-50°S) using ship surveys conducted in austral winter (July/August) and spring (November) of the years 2002-2005 and 2008. Potential sources of floating items were identified with the aid of publicly available databases and scientific reports. We found three main types of floating objects, namely floating marine debris (mainly plastic objects and Styrofoam), wood (trunks and branches), and floating kelps ( Macrocystis pyrifera and Durvillaea antarctica). Floating marine debris were abundant along most of the examined transects, with markedly lower abundances toward the southern fjord areas. Floating marine debris abundances generally corresponded to the distribution of human activities, and were highest in the Interior Sea of Chiloé, where aquaculture activities are intense. Floating wood appeared sporadically in the study area, often close to the main rivers. In accordance with seasonal river run-off, wood was more abundant along the continental coast in winter (rainy season) and in the Patagonian fjords during the spring surveys (snow melt). Densities of the two floating kelp species were similar along the continental coast, without a clear seasonal pattern. M. pyrifera densities increased towards the south, peaking in the Patagonian fjords, where it was dominant over D. antarctica. Densities of M. pyrifera in the Patagonian fjords were highest in spring. Correlation analyses between the abundances of floating objects and the distance to the nearest sources were generally non-significant, suggesting that post-supply processes affect the distribution of the floating objects in the study region. The identification of several major retention zones supports this idea. Accumulation areas of floating objects appear to be more common in the fjord zones. In general, the results underscore the abundance of floating objects throughout the study region and the fact that floating marine debris sources are mostly local, whereas floating algae may be dispersed over greater distances. Future studies should focus on the ecological role of floating objects in biota dispersal and nutrient cycling.

Hinojosa, Iván A.; Rivadeneira, Marcelo M.; Thiel, Martin

2011-03-01

171

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

172

Engineering of a red-light-activated human cAMP/cGMP-specific phosphodiesterase.  

PubMed

Sensory photoreceptors elicit vital physiological adaptations in response to incident light. As light-regulated actuators, photoreceptors underpin optogenetics, which denotes the noninvasive, reversible, and spatiotemporally precise perturbation by light of living cells and organisms. Of particular versatility, naturally occurring photoactivated adenylate cyclases promote the synthesis of the second messenger cAMP under blue light. Here, we have engineered a light-activated phosphodiesterase (LAPD) with complementary light sensitivity and catalytic activity by recombining the photosensor module of Deinococcus radiodurans bacterial phytochrome with the effector module of Homo sapiens phosphodiesterase 2A. Upon red-light absorption, LAPD up-regulates hydrolysis of cAMP and cGMP by up to sixfold, whereas far-red light can be used to down-regulate activity. LAPD also mediates light-activated cAMP and cGMP hydrolysis in eukaryotic cell cultures and in zebrafish embryos; crucially, the biliverdin chromophore of LAPD is available endogenously and does not need to be provided exogenously. LAPD thus establishes a new optogenetic modality that permits light control over diverse cAMP/cGMP-mediated physiological processes. Because red light penetrates tissue more deeply than light of shorter wavelengths, LAPD appears particularly attractive for studies in living organisms. PMID:24889611

Gasser, Carlos; Taiber, Sandra; Yeh, Chen-Min; Wittig, Charlotte Helene; Hegemann, Peter; Ryu, Soojin; Wunder, Frank; Möglich, Andreas

2014-06-17

173

Tank Tests of Twin Seaplane Floats  

NASA Technical Reports Server (NTRS)

The following report contains the most essential data for the hydrodynamic portion of the twin-float problem. The following points were successfully investigated: 1) difference between stationary and nonstationary flow; 2) effect of the shape of the step; 3) effect of distance between floats; 4) effect of nose-heavy and tail-heavy moments; 5) effect of the shape of floats; 6) maneuverability.

Herrman, H; Kempf, G; Kloess, H

1928-01-01

174

An electrically excited nanoscale light source with active angular control of the emitted light.  

PubMed

We report on the angular distribution, polarization, and spectrum of the light emitted from an electrically controlled nanoscale light source. This nanosource of light arises from the local, low-energy, electrical excitation of localized surface plasmons (LSP) on individual gold nanoparticles using a scanning tunneling microscope (STM). The gold nanoparticles (NP) are chemically synthesized truncated bitetrahedrons. The emitted light is collected through the transparent substrate and the emission characteristics (angular distribution, polarization, and spectrum) are analyzed. These three observables are found to strongly depend on the lateral position of the STM tip with respect to the triangular upper face of the gold NP. In particular, the resulting light emission changes orientation when the electrical excitation via the STM tip is moved from the base to the vertex of the triangular face. On the basis of the comparison of the experimental observations with an analytical dipole model and finite-difference time-domain (FDTD) calculations, we show that this behavior is linked to the selective excitation of the out-of-plane and in-plane dipolar LSP modes of the NP. This selective excitation is achieved through the lateral position of the tip with respect to the symmetry center of the NP. PMID:23927672

Le Moal, Eric; Marguet, Sylvie; Rogez, Benoît; Mukherjee, Samik; Dos Santos, Philippe; Boer-Duchemin, Elizabeth; Comtet, Geneviève; Dujardin, Gérald

2013-09-11

175

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

176

49 CFR 195.405 - Protection against ignitions and safe access/egress involving floating roofs.  

Code of Federal Regulations, 2013 CFR

...floating roofs. (a) After October 2, 2000, protection provided against ignitions arising out of static electricity, lightning, and stray currents during operation and maintenance activities involving aboveground breakout tanks must be in...

2013-10-01

177

Modeling International Space Station (ISS) Floating Potentials  

NASA Technical Reports Server (NTRS)

The floating potential of the International Space Station (ISS) as a function of the electron current collection of its high voltage solar array panels is derived analytically. Based on Floating Potential Probe (FPP) measurements of the ISS potential and ambient plasma characteristics, it is shown that the ISS floating potential is a strong function of the electron temperature of the surrounding plasma. While the ISS floating potential has so far not attained the pre-flight predicted highly negative values, it is shown that for future mission builds, ISS must continue to provide two-fault tolerant arc-hazard protection for astronauts on EVA.

Ferguson, Dale C.; Gardner, Barbara

2002-01-01

178

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

179

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

180

The paradox of the floating candle that continues to burn  

NASA Astrophysics Data System (ADS)

What happens after lighting a paraffin candle that is barely floating in water and kept upright with the aid of an appropriately weighted nail attached to its bottom? Presumably, it should sink because the buoyant force will decrease more than the weight. Surprisingly, the candle will continue to burn, rising slowly above the surface of the water. The reason for this is that the flame forms a well around the wick filled with molten paraffin, while the water keeps the outer walls of the candle cool and unscathed. Thus, the buoyancy hardly changes while the weight is reduced through burning, resulting in a floating candle that will rise above water. We present a quantitative model that describes the formation of the well and verify it experimentally, examining first the case of a candle in the air and then the case of a candle immersed in water.

Theodorakis, Stavros; Aristidou, Charalambos

2012-08-01

181

Gibberellins negatively regulate light-induced nitrate reductase activity in Arabidopsis seedlings.  

PubMed

In the present study, the role of phytohormone gibberellins (GAs) on regulating the nitrate reductase (NR) activity was tested in Arabidopsis seedlings. The NR activity in light-grown Col-0 seedlings was reduced by exogenous GA? (an active form of GAs), but enhanced by exogenous paclobutrazol (PAC, a gibberellin biosynthesis inhibitor), suggesting that GAs negatively regulate the NR activity in light-grown seedlings. Light is known to influence the NR activity through both photosynthesis and phytochromes. When etiolated seedlings were transferred to white or red light, both exogenously applied GA? and PAC were found to function on the NR activity only in the presence of sucrose, implying that GAs are not involved in light signaling-induced but negatively regulate photoproducts-induced NR activity. NR is regulated by light mainly at two levels: transcript level and post-translational level. Our reverse transcription (RT)-PCR assays showed that GAs did not affect the transcript levels of NIA1 and NIA2, two genes that encode NR proteins. But the divalent cations (especially Mg²?) were required for GAs negative regulation of NR activity, in view of the importance of divalent cations during the process of post-translational regulation of NR activity, which indicates that GAs very likely regulate the NR activity at the post-translational level. In the following dark-light shift analyses, GAs were found to accelerate dark-induced decrease, but retard light-induced increase of the NR activity. Furthermore, it was observed that application of G? or PAC could impair diurnal variation of the NR activity. These results collectively indicate that GAs play a negative role during light regulation of NR activity in nature. PMID:21856037

Zhang, Yongqiang; Liu, Zhongjuan; Liu, Rongzhi; Wang, Liguang; Bi, Yurong

2011-12-15

182

Wave drag on floating bodies  

PubMed Central

We measure the deceleration of liquid nitrogen drops floating at the surface of a liquid bath. On water, the friction force is found to be about 10 to 100 times larger than on a solid substrate, which is shown to arise from wave resistance. We investigate the influence of the bath viscosity and show that the dissipation decreases as the viscosity is increased, owing to wave damping. The measured resistance is well predicted by a model imposing a vertical force (i.e., the drop weight) on a finite area, as long as the wake can be considered stationary.

Le Merrer, Marie; Clanet, Christophe; Quere, David; Raphael, Elie; Chevy, Frederic

2011-01-01

183

Stem cell activation by light guides plant organogenesis  

PubMed Central

Leaves originate from stem cells located at the shoot apical meristem. The meristem is shielded from the environment by older leaves, and leaf initiation is considered to be an autonomous process that does not depend on environmental cues. Here we show that light acts as a morphogenic signal that controls leaf initiation and stabilizes leaf positioning. Leaf initiation in tomato shoot apices ceases in the dark but resumes in the light, an effect that is mediated through the plant hormone cytokinin. Dark treatment also affects the subcellular localization of the auxin transporter PIN1 and the concomitant formation of auxin maxima. We propose that cytokinin is required for meristem propagation, and that auxin redirects cytokinin-inducible meristem growth toward organ formation. In contrast to common wisdom over the last 150 years, the light environment controls the initiation of lateral organs by regulating two key hormones: auxin and cytokinin.

Yoshida, Saiko; Mandel, Therese; Kuhlemeier, Cris

2011-01-01

184

Global Night-Time Lights for Observing Human Activity  

NASA Technical Reports Server (NTRS)

We present a concept for a small satellite mission to make systematic, global observations of night-time lights with spatial resolution suitable for discerning the extent, type and density of human settlements. The observations will also allow better understanding of fine scale fossil fuel CO2 emission distribution. The NASA Earth Science Decadal Survey recommends more focus on direct observations of human influence on the Earth system. The most dramatic and compelling observations of human presence on the Earth are the night light observations taken by the Defence Meteorological System Program (DMSP) Operational Linescan System (OLS). Beyond delineating the footprint of human presence, night light data, when assembled and evaluated with complementary data sets, can determine the fine scale spatial distribution of global fossil fuel CO2 emissions. Understanding fossil fuel carbon emissions is critical to understanding the entire carbon cycle, and especially the carbon exchange between terrestrial and oceanic systems.

Hipskind, Stephen R.; Elvidge, Chris; Gurney, K.; Imhoff, Mark; Bounoua, Lahouari; Sheffner, Edwin; Nemani, Ramakrishna R.; Pettit, Donald R.; Fischer, Marc

2011-01-01

185

Blue light irradiation affects anthocyanin content and enzyme activities involved in postharvest strawberry fruit.  

PubMed

Blue light irradiation was applied to postharvest strawberry fruit to explore its influence on anthocyanin content and anthocyanin biosynthetic enzyme activities. Strawberry fruit was irradiated with blue light at 40 ?mol m(-2) s(-1) for 12 days at 5 °C. The results indicated that blue light treatment improved total anthocyanin content in strawberry fruit during storage. Meanwhile, the treatment increased the activities of glucose-6-phosphate, shikimate dehydrogenase, tyrosine ammonia-lyase, phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate/coenzyme A ligase, dihydroflavonol-4-reductase, chalcone synthase, flavanone-3-?-hydroxylase, anthocyanin synthase, and UDP-glycose flavonoid-3-O-glycosyltranferase, which suggested that the enhancement of anthocyanin concentration by blue light might result from the activation of its related enzymes. Blue light might be proposed as a supplemental light source in the storage of strawberry fruit to improve its anthocyanin content. PMID:24783962

Xu, Feng; Cao, Shifeng; Shi, Liyu; Chen, Wei; Su, Xinguo; Yang, Zhenfeng

2014-05-21

186

33 CFR 143.120 - Floating OCS facilities.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Floating OCS facilities. 143.120 Section...EQUIPMENT OCS Facilities § 143.120 Floating OCS facilities. (a) Before construction is started on a proposed floating OCS facility, the owner...

2013-07-01

187

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.

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

2012-01-01

188

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."

189

Ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory  

NASA Astrophysics Data System (ADS)

An ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory was demonstrated, with discrete distributed gold nanoparticles, tetratetracontane (TTC), pentacene as the floating-gate layer, tunneling layer, and active layer, respectively. The electron traps at the TTC/pentacene interface were significantly suppressed, which resulted in an ambipolar operation in present memory. As both electrons and holes were supplied in the channel and trapped in the floating-gate by programming/erasing operations, respectively, i.e., one type of charge carriers was used to overwrite the other, trapped, one, a large memory window, extending on both sides of the initial threshold voltage, was realized.

Han, Jinhua; Wang, Wei; Ying, Jun; Xie, Wenfa

2014-01-01

190

A Floating-Point Multiplexed DDA System  

Microsoft Academic Search

The design of a high-speed, high-accuracy floating-point digital differential analyzer (DDA) system is described. The advantages of a floating-point system are expounded. It is shown that the problem of module interconnection can be alleviated using matrix methods, and a practical implementation of a multiplexed system with a semiconductor fast data storage area is described.

Geoff Hannington; Donald G. Whitehead

1976-01-01

191

Wax scraper for floating roof tanks  

Microsoft Academic Search

A wax scraper is described for removing waxy deposits from the inside surface of floating roof storage tanks during the operation of such tanks, without requiring the removal of all obstructions from the inside surface of the tanks. The floating roof structure has affixed to it a number of support means. Each support means carries a scraper blade having scraper

H. A. Maeder; A. H. Nelson; F. R. Neely

1971-01-01

192

Customers' perceptions of floating restaurants in Egypt  

Microsoft Academic Search

Floating restaurants are a new phenomenon for dining out in Cairo, where customers can be provided not only with a meal but also an entertaining casual dining experience with unrivalled views of the Nile River. This study aims to identify customers perceptions of the floating restaurants sailing down the Nile River and also explores the different attributes that influence customer

Hany H. S. Abdelhamied

2011-01-01

193

Heaving response of a large floating platform  

Microsoft Academic Search

In this paper, we tackle a new dynamic problem of a large floating platform in a heaving harmonic motion due to 9000 performers or people simultaneously jumping in mass events. The objective is to estimate the heaving response of the floating structure so as to establish whether the participants will be at ease during their performances. By assuming the platform

C. M. Wang; T. Utsunomiya; H. S. Koh

2008-01-01

194

DRILL VESSELS FLOAT IN AERATED WATER  

Microsoft Academic Search

Model tests, calculations, and case studies prove that a floating vessel will not sink due to gas reducing the water density in or adjacent to a subsea blowout. Several floating drill vessels have been lost as a result of subsea blowouts. Reports have circulated that the rig sank into something similar to a hole in the ocean caused by gas

D. S. Hammett

1985-01-01

195

A General Equilibrium Analysis of Check Float  

Microsoft Academic Search

Households and businesses in the U.S. prefer to use checks over less costly means of payment. Earlier studies have focused on check “float” as an explanation for the continued popularity of this seemingly inefficient technology. We construct a general equilibrium model of check payment and show that the presence of float does not necessarily lead to inefficiency. However, we also

James McAndrews; William Roberds

1999-01-01

196

Algorithms for arbitrary precision floating point arithmetic  

Microsoft Academic Search

The author presents techniques for performing computations of very high accuracy using only straightforward floating-point arithmetic operations of limited precision. The validity of these techniques is proved under very general hypotheses satisfied by most implementations of floating-point arithmetic. To illustrate the applications of these techniques, an algorithm is presented which computes the intersection of a line and a line segment.

Douglas M. Priest

1991-01-01

197

Vertical pump with free floating check valve  

DOEpatents

A vertical pump with a bottom discharge having a free floating check valve isposed in the outlet plenum thereof. The free floating check valve comprises a spherical member with a hemispherical cage-like member attached thereto which is capable of allowing forward or reverse flow under appropriate conditions while preventing reverse flow under inappropriate conditions.

Lindsay, Malcolm (O'Hara Township, Allegheny County, PA)

1980-01-01

198

Locality in Syntax and Floating Numeral Quantifiers  

Microsoft Academic Search

We defend the idea that a floating quantifier observes syntactic locality with its associated noun phrase. This idea has given rise to a number of important empirical insights, including the VP-internal subject position, intermediate traces, and NP-traces. Recently, this syntactic locality of floating quantifiers has been questioned in a number of languages. We take up evidence from Japanese that purports

Shigeru Miyagawa; Koji Arikawa

2007-01-01

199

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

200

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.

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

201

Protection of the eyes against damage by light activated psoralen.  

PubMed

It is current practice to order eye protection while patients are under treatment with psoralen. There is considerable variation in the protection against long wave light provided by different sunglasses, therefore, it is necessary to write a specific prescription for sunglasses for these patients. We have found Noir Model 102 or 109 with side flaps or the Rayban dark green glass to be the most effective. PMID:431454

Peek, R; Swarbrick, P; Stevenson, R; Paver, K

1979-02-24

202

Three-dimensional floating images as overt security features  

NASA Astrophysics Data System (ADS)

3M has developed a proprietary laser process for creating three-dimensional images that appear to float above and/or below the plane of a substrate containing an array of microlenses. During the imaging process the laser records a microscopic image of the desired three-dimensional pattern in the material located at the focal point of each microlens in the array. The images exhibit motion parallax comparable to that seen from holograms and are easily visible in a wide range of ambient lighting conditions. The images are therefore similar, but not identical, to integral images, first proposed in 1908 by Lippmann. The fidelity of these floating images requires maintaining exact registration between the microlens array and the corresponding microimage array. In addition, the use of an ablative laser process for the production of the microimages enables the production of microimage features smaller than the diffraction limit (up to approximately 50,000 dpi). The images are therefore very difficult to simulate, counterfeit, or modify and are highly desirable as an overt security feature. 3M has scaled up the floating image process to produce images in ConfirmTM Retroreflective Security Laminate to authenticate passports and driver's licenses and in retroreflective license plate sheeting as the EnsureTM Virtual Security Thread to authenticate vehicle registration. This allows addition of features to a secure document that are easily verifiable, using only the human eye, by a large and widely disperse population to create an identity document that is easily identified as genuine.

Dunn, Douglas S.; Potts, Travis L.; Lorimor, Lynn E.; Jonza, James M.; Smithson, Robert M.; Maki, Stephen P.

2006-02-01

203

Role of the essential light chain in the activation of smooth muscle myosin by regulatory light chain phosphorylation.  

PubMed

The activity of smooth and non-muscle myosin II is regulated by phosphorylation of the regulatory light chain (RLC) at serine 19. The dephosphorylated state of full-length monomeric myosin is characterized by an asymmetric intramolecular head-head interaction that completely inhibits the ATPase activity, accompanied by a hairpin fold of the tail, which prevents filament assembly. Phosphorylation of serine 19 disrupts these head-head interactions by an unknown mechanism. Computational modeling (Tama et al., 2005. J. Mol. Biol. 345, 837-854) suggested that formation of the inhibited state is characterized by both torsional and bending motions about the myosin heavy chain (HC) at a location between the RLC and the essential light chain (ELC). Therefore, altering relative motions between the ELC and the RLC at this locus might disrupt the inhibited state. Based on this hypothesis we have derived an atomic model for the phosphorylated state of the smooth muscle myosin light chain domain (LCD). This model predicts a set of specific interactions between the N-terminal residues of the RLC with both the myosin HC and the ELC. Site directed mutagenesis was used to show that interactions between the phosphorylated N-terminus of the RLC and helix-A of the ELC are required for phosphorylation to activate smooth muscle myosin. PMID:24361582

Taylor, Kenneth A; Feig, Michael; Brooks, Charles L; Fagnant, Patricia M; Lowey, Susan; Trybus, Kathleen M

2014-03-01

204

Sinking and Floating: A Graphical Representation of the Concept of Density  

NSDL National Science Digital Library

Density is a derived quantity that can be confusing for middle school students. Try using a graphical depiction of mass and volume to guide students in understanding and applying this concept. In this activity, students will collect various materials, test whether each of the objects will float or sink in tap water, and measure the volume and mass of each object. By graphing the data, students will make the important conceptual leap from their initial thoughts and findings to exact criteria for floating.

Benedis-Grab, Gregory

2006-10-01

205

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

2014-02-01

206

Float polishing of optical materials.  

PubMed

The float-polishing technique has been studied to determine its suitability for producing supersmooth surfaces on optical materials, yielding a roughness of <2 A rms. An attempt was made to polish six different materials including fused quartz, Zerodur, and sapphire. The low surface roughness was achieved on fused quartz, Zerodur, and Corning experimental glass-ceramic materials, and a surface roughness of <1 A rms was obtained on O-cut single-crystal sapphire. Presumably, similar surface finishes can also be obtained on CerVit and ULE quartz, which could not be polished satisfactorily in this set of experiments because of a mismatch between sample mounting and machine configuration. PMID:20454201

Bennett, J M; Shaffer, J J; Shibano, Y; Namba, Y

1987-02-15

207

Double floating probe measurements on S3-A.  

NASA Technical Reports Server (NTRS)

Model calculations are made to explain the behavior of the potential of a pair of symmetrical floating probes used for the measurement of dc electric fields inside the plasmapause on the S3-A satellite launched on Nov. 15, 1971, into an eccentric orbit. Data representing the behavior of three regions of the plasmapause on and around Dec. 17, 1971, are discussed. The behavior of the plasmapause is found to be generally similar to that determined by previous observations involving variable magnetic activity.

Maynard, N. C.; Cauffman, D. P.

1973-01-01

208

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...

209

The light and electron microscopic distribution of acid phosphatase activity in human normal oesophageal epithelium  

Microsoft Academic Search

Synopsis  Acid phosphatase activity in human normal oesophageal epithelium was studied with light and electron microscopic techniques. The maximum activity was found to be in the prickle and lower functional layers. Electron microscopic examination revealed activity to be localized in GERL, lysosomes and membrane coating granules. These last structures probably secreted their content into the intercellular space in the central part

D. Hopwood; Kathleen R. Logan; G. Milne

1978-01-01

210

Detailed neuropsychological evaluation in a patient with Floating Harbor syndrome.  

PubMed

The Floating Harbor syndrome is a rare genetic disease characterized by a triad of clinical signs: specific dysmorphic facial features, short stature with delayed bone age, and language and speech disorders. These signs are, in most cases, associated with borderline normal intelligence to moderate delay concerning intellectual functioning. We report an extensive neuropsychological evaluation for an adult female patient and show, in particular, a severe visuospatial impairment. We discuss this deficit in the light of the previous reported cases and suggest that visuospatial abilities should be explored more systematically. PMID:22263687

Pouliquen, D; Goldenberg, A; Hannequin, D; Lecointre, C; Lechevallier, J; Cormier-Daire, V; Martinaud, O

2012-01-01

211

Receptor potential and light-induced mitochondrial activation in blowfly photoreceptor mutants  

Microsoft Academic Search

1.Simultaneous measurements of the receptor potential and the light-induced mitochondrial activation were performed in white-eyed blowflies Calliphora vicina, mutant chalky, and Lucilia cuprina, mutants wFand w'nss. The intensity dependence and the temporal dynamics were investigated.2.The characteristic curve of the light-induced mitochondrial activation vs. log intensity has an S-like shape, which is much steeper than the characteristic curve of the receptor

M. H. Mojet; J. Tinbergen; D. G. Stavenga

1991-01-01

212

A novel visible-light-sensitive strontium carbonate photocatalyst with high photocatalytic activity  

Microsoft Academic Search

A novel visible-light-sensitive strontium carbonate photocatalyst with high photocatalytic activity was prepared from strontium hydroxide by calcination in air at moderate temperature. The SrCO3 photocatalyst was characterized by UV–vis diffuse reflection spectrum, X-ray powder diffraction and Brunauer–Emmett–Teller. The photocatalytic activity of the photocatalyst was evaluated by photocatalytic oxidation of methyl blue (MB) under visible-light irradiation (?>400nm). The results show that

Limin Song; Shujuan Zhang; Bin Chen

2009-01-01

213

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

214

Light and Excess Manganese1  

PubMed Central

The effect of light intensity on antioxidants, antioxidant enzymes, and chlorophyll content was studied in common bean (Phaseolus vulgaris L.) exposed to excess Mn. Leaves of bean genotypes contrasting in Mn tolerance were exposed to two different light intensities and to excess Mn; light was controlled by shading a leaflet with filter paper. After 5 d of Mn treatment ascorbate was depleted by 45% in leaves of the Mn-sensitive genotype ZPV-292 and by 20% in the Mn-tolerant genotype CALIMA. Nonprotein sulfhydryl groups and glutathione reductase were not affected by Mn or light treatment. Ten days of Mn-toxicity stress increased leaf ascorbate peroxidase activity of cv ZPV-292 by 78% in low light and by 235% in high light, and superoxide dismutase activity followed a similar trend. Increases of ascorbate peroxidase and superoxide dismutase activity observed in cv CALIMA were lower than those observed in the susceptible cv ZPV-292. The cv CALIMA had less ascorbate oxidation under excess Mn-toxicity stress. Depletion of ascorbate occurred before the onset of chlorosis in Mn-stressed plants, especially in cv ZPV-292. Lipid peroxidation was not detected in floating leaf discs of mature leaves exposed to excess Mn. Our results suggest that Mn toxicity may be mediated by oxidative stress, and that the tolerant genotype may maintain higher ascorbate levels under stress than the sensitive genotype.

Gonzalez, Alonso; Steffen, Kenneth L.; Lynch, Jonathan P.

1998-01-01

215

Dependence of aptamer activity on opposed terminal extensions: improvement of light-regulation efficiency  

PubMed Central

Aptamers that can be regulated with light allow precise control of protein activity in space and time and hence of biological function in general. In a previous study, we showed that the activity of the thrombin-binding aptamer HD1 can be turned off by irradiation using a light activatable ‘caged’ intramolecular antisense-domain. However, the activity of the presented aptamer in its ON state was only mediocre. Here we studied the nature of this loss in activity in detail and found that switching from 5?- to 3?-extensions affords aptamers that are even more potent than the unmodified HD1. In particular we arrived at derivatives that are now more active than the aptamer NU172 that is currently in phase 2 clinical trials as an anticoagulant. As a result, we present light-regulatable aptamers with a superior activity in their ON state and an almost digital ON/OFF behavior upon irradiation.

Buff, Maximilian C. R.; Schafer, Florian; Wulffen, Bernhard; Muller, Jens; Potzsch, Bernd; Heckel, Alexander; Mayer, Gunter

2010-01-01

216

A stable blue-light-derived signal modulates ultraviolet-light-induced activation of the chalcone-synthase gene in cultured parsley cells  

Microsoft Academic Search

Run-off transcription assays were used to demonstrate that both the ultraviolet (UV)-B and blue-light receptors control transcription rates for chalcone-synthase mRNA in the course of light-induced flavonoid synthesis in parsley (Petroselinum crispum Miller (A.W. Hill)) cell-suspension cultures. Blue and red light alone, presumably acting via a blue-light receptor and active phytochrome (far-red absorbing form) respectively, can induce accumulation of chalcone-synthase

S. Ohl; K. Hahlbrock; E. Schäfer

1989-01-01

217

Light-dependent activity of the antitumor antibiotics ravidomycin and desacetylravidomycin.  

PubMed Central

The antitumor antibiotics ravidomycin and desacetylravidomycin were studied by the biochemical lambda prophage induction assay. In this assay, induction of the enzyme beta-galactosidase is measured as a specific indication of the ability of an agent to directly or indirectly damage DNA. Induction was observed only when these two antibiotics were irradiated with light in the presence of the indicator organism. Drug treated with light followed by incubation with the indicator organism in the dark did not cause induction. Light in both the near UV and visible wave length ranges activated these antibiotics; near UV and visible blue wavelengths were most effective, while 597-nm light was totally ineffective. The amount of induction caused by these drugs varied directly with the dosage of light provided. Bacterial growth inhibition, as well as cytotoxicity for a human colon carcinoma cell line, was also dramatically enhanced by light. These data suggest that ravidomycin and desacetylravidomycin are potent photosensitizing, DNA-damaging agents.

Greenstein, M; Monji, T; Yeung, R; Maiese, W M; White, R J

1986-01-01

218

Vane Design for the Coastal Ocean Lagrangian (COOL) Float.  

National Technical Information Service (NTIS)

Coastal Ocean Lagrangian (COOL) float is an isopycnal f/h float equipped with vanes to measure vertical velocity. We determined the sensitivity of the float's rotation rate to vertical velocity past it for different vane geometries. The float's response t...

J. Rajamony S. Peterson J. Fontaine D. Hebert T. Rossby

1996-01-01

219

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

220

Determining the Typical Nanoflare Cadence in Active Regions: Modeling Light Curves of Active Regions  

NASA Astrophysics Data System (ADS)

Active region coronal loops visible at 1MK are likely composed of many unresolved strands, heated by storms of impulsive nanoflares. Though well-studied, these loops often contribute only a fraction of the total emission in an active region; the degree to which the entire active region is heated in the same manner as loops are is highly debated. Is the majority of coronal active region plasma heated impulsively, or is the majority of the heating quasi-steady? Addressing this question is complicated by the fact that the corona is optically thin: many thousands of strands which are heated completely independently are contributing to the total emission along a given line of sight. Furthermore, certain geometries preclude even the best background subtraction methods from fully isolating the emission from even a single coronal loop. Therefore, a different and necessary approach to analyzing active region heating is to account for emission along the line of sight from all of the contributing strands. We model the active region corona as a line-of-sight integration of many thousands of completely independently heated strands. The emission from these flux tubes may be time dependent, quasi-steady, or a mix of both, depending on the cadence of heat release on each strand. We examine a full range of heat cadences from effectively steady (heat pulse repeat time << plasma cooling time) to fully impulsive (heat pulse repeat time >> plasma cooling time) and model the resulting emission when superposing strands undergoing these differing heat cycles. We demonstrate that despite the superposition of randomly heated strands, different distributions of heat cadences produce distinct signatures in light curves observed with multi-wavelength and high time cadence data, such as those from the AIA telescopes on SDO. For this reason, high time cadence spectral information for lines sensitive to the 1-10 MK range will be especially useful in future missions. Using these model predictions, we evaluate the typical cadence of heat release in different active regions and patterns therein, which is a crucial constraint on coronal heating mechanisms.

Viall, N. M.; Klimchuk, J. A.

2011-12-01

221

Comparison of self-cleaning properties of three titania coatings on float glass  

NASA Astrophysics Data System (ADS)

This work compares the self-cleaning properties of experimental TiO 2 and TiO 2-Ag coatings on float glass with a commercial self-cleaning glass. In the experimental surfaces, TiO 2 coating was applied to float glass via the sol-gel route, while TiO 2-Ag coating was applied by the liquid flame spray method, which deposits TiO 2-Ag composite nanoparticles on the surface. The effect of the coatings on the surface wettability and the activation time for achieving hydrophilicity was studied through water contact angle as a function of exposure time to UV light. The surface morphology was investigated by using scanning electron microscopy (SEM) and confocal optical microscopy. The photocatalytic activity of the coatings was examined with methylene blue and stearic acid degradation tests. Finally, the soil attachment to the surfaces was tested with a sebum-based model soil. The sol-gel TiO 2 coating became superhydrophilic within a few hours, while the activation time needed for the commercial titania coated glass was several days. The surface with the TiO 2-Ag nanoparticles did not show any marked changes in the water contact angle. The commercial titania coated and the sol-gel TiO 2 surfaces showed self-cleaning properties and clearly lower attachment of soil than the uncoated and TiO 2-Ag coated surfaces. The difference in the interaction of the surfaces with the organic contaminants was assumed to depend mainly on differences in the thickness of the coatings.

Piispanen, Minna; Hupa, Leena

2011-11-01

222

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

223

Light activates rotations of bacteriorhodopsin in the purple membrane  

SciTech Connect

To investigate how a photoactivated chromophore drives the proton pump mechanism of bacteriorhodopsin, the authors have observed how the chromophore rotates during the photocycle. To do this, they examined the dichroism induced in aqueous suspensions of purple membrane fragments by flashes of linearly polarized light. It was found that the flash stimulates both the photocycling chromophores and their noncycling neighbors to undergo large (> 10/sup 0/-20/sup 0/) rotations within the membrane during the photocycle, and that these two chromophore populations undergo distinctly different sequences of rotations. All these rotations could be eliminated by glutaraldehyde fixation as well as by embedding unfixed fragments in polyacrylamide or agarose gels. Thus, in these immbolizing preparations the chromophore can photocycle without rotating inside a bacteriorhodopsin monomer by more than our detection limit of 2/sup 0/-5/sup 0/. The large rotations observed in aqueous suspensions of purple membranes were probably due to rotations of entire protein monomers. The process by which a photocycyling monomer causes its noncycling neighbors to rotate may help explain the highly cooperative behavior bacteriorhodopsin exhibits when it is aggregated into crystalline arrays of trimers.

Ahl, P.L.; Cone, R.A.

1984-06-01

224

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.

Adidharma, Widya; Leach, Greg; Yan, Lily

2012-01-01

225

Preview of Mars Curiosity Parade Float  

NASA Video Gallery

Jim Green, Director of the Science Mission Directorate Planetary Systems Division at NASA Headquarters, describes the replica of the Mars Curiosity Rover on the second NASA float in Monday's inaugu...

226

Current Mirror with Programmable Floating Gate.  

National Technical Information Service (NTIS)

Systems and methods are discussed for using a floating-gate MOSFET as a programmable reference circuit. One example of the programmable reference circuit is a programmable voltage reference source, while a second example of a programmable reference circui...

G. J. Serrano P. E. Hasler

2006-01-01

227

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

228

A floating-point technique for extending the available precision  

Microsoft Academic Search

A technique is described for expressing multilength floating-point arithmetic in terms of singlelength floating point arithmetic, i.e. the arithmetic for an available (say: single or double precision) floating-point number system. The basic algorithms are exact addition and multiplication of two singlelength floating-point numbers, delivering the result as a doublelength floating-point number. A straight-forward application of the technique yields a set

T. J. Dekker

1971-01-01

229

Floating drug delivery systems: A review  

Microsoft Academic Search

The purpose of writing this review on floating drug delivery systems (FDDS) was to compile the recent literature with special\\u000a focus on the principal mechanism of floatation to achieve gastric retention. The recent developments of FDDS including the\\u000a physiological and formulation variables affecting gastric retention, approaches to design single-unit and multiple-unit floating\\u000a systems, and their classification and formulation aspects are

Shweta Arora; Javed Ali; Alka Ahuja; Roop K. Khar; Sanjula Baboota

2005-01-01

230

Multiple valued floating potentials of Langmuir probes  

NASA Technical Reports Server (NTRS)

It is shown that Langmuir probes can have three different floating potentials in plasmas produced by a hot filament discharge in a multi-dipole device when the primary and secondary electron currents are comparable. The measured floating potential depends on the probe's initial condition - the most negative and the least negative potentials are found to be stable and the in-between value is found to be unstable. Results are compared to a simple theoretical model.

Nam, Cheol-Hee; Hershkowitz, N.; Cho, M. H.; Intrator, T.; Diebold, D.

1988-01-01

231

Decimal Floating-Point: Algorism for Computers  

Microsoft Academic Search

Decimal arithmetic is the norm in human calculations, and human-centric applications must use a decimal floating-point arithmetic to achieve the same results. Initial benchmarks indicate that some applications spend 50% to 90% of their time in decimal processing, because software decimal arithmetic suffers a 100× to 1000× performance penalty over hardware. The need for decimal floating-point in hardware is urgent.

Michael F. Cowlishaw; Coventry CV

2003-01-01

232

Mixed abstractions for floating-point arithmetic  

Microsoft Academic Search

Floating-point arithmetic is essential for many embedded and safety-critical systems, such as in the avionics industry. Inaccuracies in floating-point calculations can cause subtle changes of the control flow, potentially leading to disastrous errors. In this paper, we present a simple and general, yet powerful framework for building abstractions from formulas, and instantiate this framework to a bit-accurate, sound and complete

Angelo Brillout; Daniel Kroening; Thomas Wahl

2009-01-01

233

Floating distal interphalangeal joint injury: case report.  

PubMed

A 37-year-old man sustained a floating distal interphalangeal (DIP) joint injury to the left index finger. The diagnosis was not confirmed until 3 months after the injury because of minimal deformity of the injured finger. Open reduction and internal fixation of the dorsally displaced floating DIP joint was carried out. Bone union was achieved but radiographs revealed osteoarthritis of the DIP joint. PMID:20724082

Kawamura, Kenji; Omokawa, Shohei; Shimizu, Takamasa; Tanaka, Yasuhito

2010-09-01

234

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.

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

235

Floating assembly of diatom Coscinodiscus sp. microshells.  

PubMed

Diatoms have silica frustules with transparent and delicate micro/nano scale structures, two dimensional pore arrays, and large surface areas. Although, the diatom cells of Coscinodiscus sp. live underwater, we found that their valves can float on water and assemble together. Experiments show that the convex shape and the 40 nm sieve pores of the valves allow them to float on water, and that the buoyancy and the micro-range attractive forces cause the valves to assemble together at the highest point of water. As measured by AFM calibrated glass needles fixed in manipulator, the buoyancy force on a single floating valve may reach up to 10 ?N in water. Turning the valves over, enlarging the sieve pores, reducing the surface tension of water, or vacuum pumping may cause the floating valves to sink. After the water has evaporated, the floating valves remained in their assembled state and formed a monolayer film. The bonded diatom monolayer may be valuable in studies on diatom based optical devices, biosensors, solar cells, and batteries, to better use the optical and adsorption properties of frustules. The floating assembly phenomenon can also be used as a self-assembly method for fabricating monolayer of circular plates. PMID:22387476

Wang, Yu; Pan, Junfeng; Cai, Jun; Zhang, Deyuan

2012-03-30

236

MAINTAINED ACTIVITY IN THE CAT'S RETINA IN LIGHT AND DARKNESS  

PubMed Central

Nervous activity has been recorded from the unopened eye of decerebrate cats. Recordings were made with metal electrodes or with small micropipettes from ganglion cells or nerve fibers. Continuous maintained discharges were seen in all ganglion cells during steady illumination of their receptive fields, as well as in complete darkness. Possible artefacts, such as electrode pressure, abnormal circulation, anesthetic, and several other factors have been excluded as the source of the maintained discharge. Visual stimuli are therefore transmitted by modulating the ever present background activity. Discharge frequencies were measured following changes of retinal illumination. No consistent patterns of frequency change were found. The maintained discharge frequency may be permanently increased or decreased, or may remain practically unchanged by altering the steady level of illumination. In addition, there were often transient frequency changes during the first 5 to 10 minutes after changing illumination, before a final steady rate was established. A statistical analysis of the impulse intervals of the maintained discharge showed: (a) the intervals were distributed according to the gamma distribution (Pearson's type III), (b) the first serial correlation coefficient of the intervals was between –0.10 and –0.24, with a mean value of –0.17, which is significantly different from zero, (c) the higher order serial correlation coefficients were not significantly different from zero. Thus the firing probability at any time depends on the times of occurrence of the two preceding impulses only, and in such a way as to indicate that each impulse is followed by a transient depression of excitability that outlasts the following impulse. The possible sites at which spontaneous or maintained activity may originate in the retina are discussed.

Kuffler, S. W.; Fitzhugh, R.; Barlow, H. B.

1957-01-01

237

Remote Detection of Biological Activity using Circular Polarization of Light  

NASA Astrophysics Data System (ADS)

The identification of a universal biosignature that could be sensed remotely is critical to the prospects for success in the search for life elsewhere in the universe. A candidate universal biosignature is homochirality, which is likely to be a generic property of all biochemical life. Due to the optical activity of chiral biological molecules, this unique characteristic may provide a suitable remote sensing probe using circular polarization spectroscopy. Photosynthetic microbial organisms are of major importance to astrobiology, are plausibly commonplace, and are amenable to remote sensing. We show that their circular polarization spectra exhibit distinctive polarization features. Circular polarization spectroscopy could provide a powerful remote sensing technique for generic life searches.

Sparks, W. B.

2010-10-01

238

Light stimulates tyrosine hydroxylase activity and dopamine synthesis in retinal amacrine neurons.  

PubMed

Retinal dopamine-containing amacrine neurons are rapidly activated by light, as shown by an increase in the rate of dopamine formation in vivo and a concomitant increase in the activity of tyrosine hydroxylase, measured in vitro with a subsaturating concentration of pteridine cofactor. Activation of tyrosine hydroxylase also occurs when isolated eyes from rats killed in the dark are exposed to a strobe light. Studies of amacrine neurons should provide basic data about the biochemical processing of visual information, as well as the physiological presynaptic regulatory mechanisms of dopamine-containing neurons. PMID:30997

Iuvone, P M; Galli, C L; Garrison-Gund, C K; Neff, N H

1978-11-24

239

A Classroom Demonstration of Rayleigh Light Scattering in Optically Active and Inactive Systems.  

ERIC Educational Resources Information Center

Argues that the concept of optical activity is vague to students because it is difficult for instructors to demonstrate the phenomenon in the classroom. Presents a demonstration that allows students to observe and manipulate the optical path of polarized light through optically inactive and active solutions. (CCM)

Pecina, Monica Avalos; Smith, Charles A.

1999-01-01

240

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

241

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.

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

242

Impact of floating population on the epidemic of tuberculosis: a spatial analysis  

NASA Astrophysics Data System (ADS)

According to the report issued by the Health Bureau of Beijing that the number of newly registered active pulmonary tuberculosis cases in floating population exceeded half of that in registered permanent residence in 2006. More attention has been paid to the tuberculosis of floating population. Materials and methods: The population data included in the studied was reported by the Beijing Police Bureau in 2004, and the case source from 2004 to 2006 was provided by Beijing Research Institute for TB Control. Two GIS-based methods have been used to detect the hot spots of tuberculosis in 18 districts of Beijing. Results: The distributions of hot spots of tuberculosis in Beijing are significantly associated with that of floating people. Most likely cluster from all population matches with those from floating population, which is stable from 2004 to 2006. Conclusion: The spatial analytical results indicated that the floating population has a drastic influence on the epidemic of tuberculosis in Beijing. The tuberculosis control measures should incorporate the effect of floating population.

Jia, Zhongwei; He, Xiaoxin; Zhao, Wenjuan; An, Yansheng; Cao, Wuchun; Li, Xiaowen

2007-08-01

243

Block of Gap Junctions Eliminates Aberrant Activity and Restores Light Responses during Retinal Degeneration  

PubMed Central

Retinal degeneration leads to progressive photoreceptor cell death, resulting in vision loss. Subsequently, inner retinal neurons develop aberrant synaptic activity, compounding visual impairment. In retinal ganglion cells, light responses driven by surviving photoreceptors are obscured by elevated levels of aberrant spiking activity. Here, we demonstrate in rd10 mice that targeting disruptive neuronal circuitry with a gap junction antagonist can significantly reduce excessive spiking. This treatment increases the sensitivity of the degenerated retina to light stimuli driven by residual photoreceptors. Additionally, this enhances signal transmission from inner retinal neurons to ganglion cells, potentially allowing the retinal network to preserve the fidelity of signals either from prosthetic electronic devices, or from cells optogenetically modified to transduce light. Thus, targeting maladaptive changes to the retina allows for treatments to use existing neuronal tissue to restore light sensitivity, and to augment existing strategies to replace lost photoreceptors.

Toychiev, Abduqodir H.; Ivanova, Elena; Yee, Christopher W.

2013-01-01

244

Inhibition of cathepsin activity in a cell-based assay by a light-activated ruthenium compound.  

PubMed

Light-activated inhibition of cathepsin activity was demonstrated in a cell-based assay. Inhibitors of cathepsin?K, Cbz-Leu-NHCH2 CN (2) and Cbz-Leu-Ser(OBn)-CN (3), were caged within the complexes cis-[Ru(bpy)2 (2)2 ]Cl2 (4) and cis-[Ru(bpy)2 (3)2 ](BF4 )2 (5) (bpy=2,2'-bipyridine) as 1:1 mixtures of ? and ? stereoisomers. Complexes 4 and 5 were characterized by (1) H?NMR, IR, and UV/Vis spectroscopies and electrospray mass spectrometry. Photochemical experiments confirm that 4 releases two molecules of 2 upon exposure to visible light for 15?min, whereas release of 3 by 5 requires longer irradiation times. IC50 determinations against purified cathepsin?K under light and dark conditions with 4 and 5 confirm that inhibition is enhanced from 35- to 88-fold, respectively, upon irradiation with visible light. No apparent toxicity was observed for 4 in the absence or presence of irradiation in bone marrow macrophage (BMM) or PC3 cells, as determined by MTT assays, at concentrations up to 10??M. Compound 5 is well tolerated at lower concentrations (<1??M), but does show growth-inhibitory effects at higher concentrations. Confocal microscopy experiments show that 4 decreases intracellular cathepsin activity in osteoclasts with light activation. These results support the further development of caged nitrile-based inhibitors as chemical tools for investigating spatial aspects of proteolysis within living systems. PMID:24729544

Respondek, Tomasz; Sharma, Rajgopal; Herroon, Mackenzie K; Garner, Robert N; Knoll, Jessica D; Cueny, Eric; Turro, Claudia; Podgorski, Izabela; Kodanko, Jeremy J

2014-06-01

245

Light activation of the LOV protein Vivid generates a rapidly exchanging dimer†‡  

PubMed Central

The fungal photoreceptor Vivid (VVD) plays an important role in the adaptation of blue-light responses in Neurospora crassa. VVD, an FAD-binding LOV (Light, Oxygen, Voltage) protein, couples light-induced cysteinyl-adduct formation at the flavin ring to conformational changes in the N-terminal cap (Ncap) of the VVD PAS domain. Size-exclusion chromatography (SEC), equilibrium ultracentrifugation, and static and dynamic light scattering show that these conformational changes generate a rapidly exchanging VVD dimer, with an expanded hydrodynamic radius. A three-residue N-terminal ?-turn that assumes two different conformations in a crystal structure of a VVD C71V variant is essential for light-state dimerization. Residue substitutions at a critical hinge between the Ncap and PAS core can inhibit or enhance dimerization, whereas a Tyr to Trp substitution at the Ncap-to-PAS interface stabilizes the light-state dimer. Cross-linking through engineered disulfides indicates that the light-state dimer differs considerably from the dark-state dimer found in VVD crystal structures. These results verify the role of Ncap conformational changes in gating the photic response of Neurospora crassa, and indicate that LOV:LOV homo or hetero dimerization may be a mechanism for regulating light-activated gene expression.

Zoltowski, Brian D.; Crane, Brian R.

2009-01-01

246

Cross-Polarized Reflected Light Measurement of Fast Optical Responses Associated with Neural Activation  

PubMed Central

We developed an optical probe for cross-polarized reflected light measurements and investigated optical signals associated with electrophysiological activation in isolated lobster nerves. The cross-polarized baseline light intensity (structural signal) and the amplitude of the transient response to stimulation (functional signal) measured in reflected mode were dependent on the orientation of the nerve axis relative to the polarization plane of incident light. The maximum structural signal and functional response amplitude were observed at 45°, and the ratio of functional to structural signals was approximately constant across orientations. Functional responses were measured in single trials in both transmitted and reflected geometries and responses had similar waveforms. Both structural and functional signals were an order of magnitude smaller in reflected than in transmitted light measurements, but functional responses had similar signal/noise ratios. We propose a theoretical model based on geometrical optics that is consistent with experimental results. In the model, the cross-polarized structural signal results from light reflection from axonal fibers and the transient functional response arises from axonal swelling associated with neural activation. Polarization-sensitive reflected light measurements could greatly enhance in vivo imaging of neural activation since cross-polarized responses are much larger than scattering signals now employed for dynamic functional neuroimaging.

Yao, Xin-Cheng; Foust, Amanda; Rector, David M.; Barrowes, Benjamin; George, John S.

2005-01-01

247

Individual and combined suppressive effects of submerged and floating-leaved macrophytes on algal blooms.  

PubMed

Shallow lakes and ponds are often characterised either by clear water with abundant submerged macrophytes or by turbid water with abundant phytoplankton. Blooms of toxic filamentous blue-green algae (cyanobacteria) often dominate the phytoplankton community in eutrophic lakes, which threatens ecological functions and biodiversity of freshwater ecosystems. We studied a simple lake model in order to evaluate individual and combined suppressive effects of rooted submerged and rooted floating-leaved macrophytes on algal blooms. Floating-leaved plants are superior competitors for light, whereas submerged plants absorb and reduce available phosphorus in a water column that rooted floating-leaved plants exploit to a lesser extent. We found that mixed vegetation that includes both submerged and floating-leaved plants is more resistant than vegetation comprised by a single plant type to algal invasion triggered by phosphorus loading. In addition, competitive exclusion of submerged plants by floating-leaved plants may promote an algal bloom. These predictions were confirmed by the decision tree analysis of field data from 35 irrigation ponds in Hyogo Prefecture, Japan. PMID:23219493

Seto, Mayumi; Takamura, Noriko; Iwasa, Yoh

2013-02-21

248

Effects of light, food, and methamphetamine on the circadian activity rhythm in mice.  

PubMed

The circadian rhythm of locomotor activity in mice is synchronized to environmental factors such as light and food availability. It is well-known that entrainment of the activity rhythm to the light-dark cycle is attained by the circadian pacemaker in the suprachiasmatic nucleus (SCN). Locomotor activity is also controlled by two extra-SCN oscillators; periodic food availability entrains the food-entrainable oscillator (FEO) and constant consumption of low-dose methamphetamine reveals the output of the methamphetamine-sensitive circadian oscillator (MASCO). In this study, we sought to investigate the relationship between the SCN, FEO, and MASCO by examining the combinatorial effects of light, food restriction, and/or methamphetamine on locomotor activity. To investigate coupling between the SCN and FEO, we tested whether food anticipatory activity, which is the output of the FEO, shifted coordinately with phase shifts of the light-dark cycle. We found that the phase of food anticipatory activity was phase-delayed or phase-advanced symmetrically with the respective shift of the light-dark cycle, suggesting that the FEO is strongly coupled to the SCN and the phase angle between the SCN and FEO is maintained during ad libitum feeding. To examine the effect of methamphetamine on the output of the FEO, we administered methamphetamine to mice undergoing restricted feeding and found that food-entrained activity was delayed by methamphetamine treatment. In addition, restricted feeding induced dissociation of the MASCO and SCN activity rhythms during short-term methamphetamine treatment, when these rhythms are typically integrated. In conclusion, our data suggest that the outputs of the SCN, FEO and MASCO collectively drive locomotor activity. PMID:24530262

Pendergast, Julie S; Yamazaki, Shin

2014-04-10

249

Use of adsorption isotherms of light normal alkanes for characterizing microporous activated carbons  

SciTech Connect

Adsorption isotherms of light normal alkanes on three different activated carbons were measured and compared with benzene adsorption isotherms on these carbons. Analysis by means of the Dubinin-Radushkevich equation revealed the utility of the adsorption isotherms of ethane, propane, and n-butane for describing the microporosity of activated carbons. On the basis of these studies, the authors recommend that n-butane be used as a reference adsorbate for characterization of microporous activated carbons.

Lu, X.; Jaroniec, M.; Madey, R. (Kent State Univ., OH (USA))

1991-01-01

250

Degradation of pyrimethanil in soil: influence of light, oxygen, and microbial activity.  

PubMed

The research was carried out in order to verify the influence that light, oxygen, and microbial activity have on the degradability of pyrimethanil (PYR) in soil. The products of degradation were also identified and their evolution in time evaluated. The results indicate that the molecule is more persistent in the absence of light, oxygen, and microbial activity. The order of importance of these three factors is as follows: light < microbial activity < oxygen. The following products of degradation were identified: (1) benzoic acid, (2) cis,cis-muconic acid, (3) hydroxyl-4,6-dimethyl-2-pirimidinamine, (4) N'-ethyl-N-hydroxyformamidine, and (5) 4,6-dimethyl-2-piridinamine, which appeared different from those reported in literature for the degradation of PYR in abiotic conditions. This result suggests that the degradation in soil is mainly biotic. PMID:16393896

Vanni, A; Anfossi, L; Cignetti, A; Baglieri, A; Gennari, M

2006-01-01

251

Entrainment of the circadian rhythm in the locomotor activity of Mus booduga by red and white light.  

PubMed

The role of red light (greater than 610 nm) and white incandescent light in entraining the circadian locomotor activity rhythm of the field mouse Mus booduga has been studied using different light intensities. Red light of less than 150 microW/cm2 caused negative masking and greater than 150 microW/cm2 caused entrainment. Such intensity dependent masking and entrainment were also obtained with white incandescent light. PMID:3850025

Viswanathan, N; Chandrashekaran, M K

1985-01-01

252

Enhanced photosynthetic activity in Spinacia oleracea by spectral modification with a photoluminescent light converting material.  

PubMed

The spectral conversion of incident sunlight by appropriate photoluminescent materials has been a widely studied issue for improving the efficiency of photovoltaic solar energy harvesting. By using phosphors with suitable excitation/emission properties, also the light conditions for plants can be adjusted to match the absorption spectra of chlorophyll dyes, in this way increasing the photosynthetic activity of the plant. Here, we report on the application of this principle to a high plant, Spinacia oleracea. We employ a calcium strontium sulfide phosphor doped with divalent europium (Ca0.4Sr0.6S:Eu(2+), CSSE) on a backlight conversion foil in photosynthesis experiments. We show that this phosphor can be used to effectively convert green to red light, centering at a wavelength of ~650 nm which overlaps the absorption peaks of chlorophyll a/b pigments. A measurement system was developed to monitor the photosynthetic activity, expressed as the CO2 assimilation rate of spinach leaves under various controlled light conditions. Results show that under identical external light supply which is rich in green photons, the CO2 assimilation rate can be enhanced by more than 25% when the actinic light is modified by the CSSE conversion foil as compared to a purely reflecting reference foil. These results show that the phosphor could be potentially applied to modify the solar spectrum by converting the green photons into photosynthetically active red photons for improved photosynthetic activity. PMID:24514932

Xia, Qi; Batentschuk, Miroslaw; Osvet, Andres; Richter, Peter; Häder, Donat P; Schneider, Juergen; Brabec, Christoph J; Wondraczek, Lothar; Winnacker, Albrecht

2013-11-01

253

Visible light photocatalytic activity of TiO2 nanoparticles hybridized by conjugated derivative of polybutadiene  

NASA Astrophysics Data System (ADS)

A series of conjugated polymer/TiO2 (CP/TiO2) nanocomposites were prepared from TiO2 and commercial polybutadiene. The as-prepared CP/TiO2 nanocomposites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), Raman Spectroscopy, UV–vis diffuse reflectance spectroscopy (UV–vis DRS), and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of CP/TiO2 nanocomposites were investigated by monitoring the degradation of methyl orange aqueous solution under visible light irradiation. The effects of preparation conditions (such as the mass ratio of PB to TiO2 in suspensions for PB/TiO2 preparation, heat-treatment temperature and time) of CP/TiO2 nanocomposites on their visible light photocatalytic activity were investigated. The results show that the CP/TiO2 nanocomposites have excellent visible light photocatalytic activity. As the content of conjugated polymer on the TiO2 surface, heat-treatment temperature and time increase, the visible light photocatalytic activity increases at first and then decreases. The visible light photocatalytic mechanism of the CP/TiO2 nanocomposites has been discussed.

Liu, Guoquan; Liu, Longchen; Song, Jinran; Liang, Jiudi; Luo, Qingzhi; Wang, Desong

2014-05-01

254

Synthesis of visible light-activated TiO{sub 2} photocatalyst via surface organic modification  

SciTech Connect

A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to sol-gel-hydrothermal synthesized TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex that was confirmed by the FT-IR and XPS spectra. Due to the existence of surface complex, the absorption edge of as-prepared TDI-modified TiO{sub 2} nanomaterial extended well into visible region. Compared with unmodified TiO{sub 2} and Degussa P25, the TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation. - Graphical abstract: A visible light-activated TiO{sub 2} photocatalyst was successfully synthesized by the surface organic modification to TiO{sub 2}. The surface hydroxyls of TiO{sub 2} nanoparticles reacted with the active -NCO groups of tolylene diisocyanate (TDI) to form a surface complex. The TDI-modified TiO{sub 2} photocatalysts showed higher activity for the photocatalytic degradation of methylene blue under visible light irradiation.

Jiang Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Graduate School of Chinese Academy of Sciences, Beijing 100039 (China)], E-mail: jdred@sxicc.ac.cn; Xu Yao [Key Laboratory of Carbon Material, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: xuyao@sxicc.ac.cn; Hou Bo [Key Laboratory of Carbon Material, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Wu Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Sun Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)], E-mail: yhsun@sxicc.ac.cn

2007-05-15

255

Light- and GTP-activated hydrolysis of phosphatidylinositol bisphosphate in squid photoreceptor membranes  

SciTech Connect

Light stimulates the hydrolysis of exogenous, (/sup 3/H)inositol-labeled phosphatidylinositol bisphosphate (PtdInsP2) added to squid photoreceptor membranes, releasing inositol trisphosphate (InsP3). At free calcium levels of 0.05 microM or greater, hydrolysis of the labeled lipid is stimulated up to 4-fold by GTP and light together, but not separately. This activity is the biochemical counterpart of observations on intact retina showing that a rhodopsin-activated GTP-binding protein is involved in visual transduction in invertebrates, and that InsP3 release is correlated with visual excitation and adaptation. Using an in vitro assay, we investigated the calcium and GTP dependence of the phospholipase activity. At calcium concentrations between 0.1 and 0.5 microM, some hydrolysis occurs independently of GTP and light, with a light- and GTP-activated component superimposed. At 1 microM calcium there is no background activity, and hydrolysis absolutely requires both GTP and light. Ion exchange chromatography on Dowex 1 (formate form) of the water-soluble products released at 1 microM calcium reveals that the product is almost entirely InsP3. Invertebrate rhodopsin is homologous in sequence and function to vertebrate visual pigment, which modulates the concentration of cyclic GMP through the mediation of the GTP-binding protein transducin. While there is some evidence that light also modulates PtdInsP2 content in vertebrate photoreceptors, the case for its involvement in phototransduction is stronger for the invertebrate systems. The results reported here support the scheme of rhodopsin----GTP-binding protein----phospholipase C activation in invertebrate photoreceptors.

Baer, K.M.; Saibil, H.R.

1988-01-05

256

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

257

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. 5 figs.

Banasiuk, H.A.

1983-08-23

258

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

259

Light-activated ion channels in solitary photoreceptors of the scallop Pecten irradians  

PubMed Central

Retinas from the scallop Pecten irradians were enzymatically dispersed, yielding a large number of isolated photoreceptors suitable for tight- seal recording. Whole-cell voltage clamp measurements demonstrated that the phototransducing machinery remained intact: quantum bumps could be elicited by dim illumination, while brighter flashes produced larger, smooth photocurrents. Single-channel currents specifically activated by light were recorded in cell-attached patches, and were almost exclusively confined to the rhabdomeric region. Their density is sufficiently high to account for the macroscopic photoresponse. Channel activation is graded with stimulus intensity in a range comparable to that of the whole-cell response, and can be recorded with illumination sufficiently dim to evoke only quantum bumps. Light-dependent channel openings are very brief, on average 1 ms or less at 20-22 degrees C, apparently not because of blockage by extracellular divalent cations. The mean open time does not change substantially with stimulus intensity. In particular, since dwell times are in the millisecond range even with the dimmest lights, the channel closing rate does not appear to be the rate-limiting step for the decay kinetics of discrete waves. The latency of the first opening after light onset is inversely related to light intensity, and the envelope of channel activity resembles the time course of the whole-cell photocurrent. Unitary currents are inward at resting potential, and have a reversal voltage similar to that of the macroscopic light response. Voltage modulates the activity of light-sensitive channels by increasing the opening rate and also by lengthening the mean open times as the patch is depolarized. The unitary conductance of the predominant class of events is approximately 48 pS, but at least one additional category of smaller- amplitude openings was observed. The relative incidence of large and small events does not appear to be related in a simple way to the state of adaptation of the cell.

1992-01-01

260

Locomotor activity rhythm in four wrasse species under varying light conditions  

Microsoft Academic Search

\\u000a Abstract  Under controlled laboratory conditions, the locomotor activity rhythms of four species of wrasses (Suezichthys gracilis, Thalassoma cupido, Labroides dimidiatus andCirrhilabrus temminckii) were individually examined using an actograph with infra-red photo-electric switches in a dark room at temperatures of 21.3–24.3°C,\\u000a for 7 to 14 days. The locomotor activity ofS. gracilis occurred mostly during the light period under a light-dark cycle regimen

Genjirou Nishi

1990-01-01

261

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

262

Energy Transfer in Light-Adapted Photosynthetic Membranes: From Active to Saturated Photosynthesis  

PubMed Central

In bacterial photosynthesis light-harvesting complexes, LH2 and LH1 absorb sunlight energy and deliver it to reaction centers (RCs) with extraordinarily high efficiency. Submolecular resolution images have revealed that both the LH2:LH1 ratio, and the architecture of the photosynthetic membrane itself, adapt to light intensity. We investigate the functional implications of structural adaptations in the energy transfer performance in natural in vivo low- and high-light-adapted membrane architectures of Rhodospirillum photometricum. A model is presented to describe excitation migration across the full range of light intensities that cover states from active photosynthesis, where all RCs are available for charge separation, to saturated photosynthesis where all RCs are unavailable. Our study outlines three key findings. First, there is a critical light-energy density, below which the low-light adapted membrane is more efficient at absorbing photons and generating a charge separation at RCs, than the high-light-adapted membrane. Second, connectivity of core complexes is similar in both membranes, suggesting that, despite different growth conditions, a preferred transfer pathway is through core-core contacts. Third, there may be minimal subareas on the membrane which, containing the same LH2:LH1 ratio, behave as minimal functional units as far as excitation transfer efficiency is concerned.

Fassioli, Francesca; Olaya-Castro, Alexandra; Scheuring, Simon; Sturgis, James N.; Johnson, Neil F.

2009-01-01

263

Diacylglycerol Activates the Light-Dependent Channel TRP in the Photosensitive Microvilli of Drosophila melanogaster Photoreceptors.  

PubMed

Drosophila light-dependent channels, TRP and TRPL, reside in the light-sensitive microvilli of the photoreceptor's rhabdomere. Phospholipase C mediates TRP/TRPL opening, but the gating process remains unknown. Controversial evidence has suggested diacylglycerol (DAG), polyunsaturated fatty acids (PUFAs, a DAG metabolite), phosphatidylinositol bisphosphate (PIP2), and H(+) as possible channel activators. We tested each of them directly in inside-out TRP-expressing patches excised from the rhabdomere, making use of mutants and pharmacology. When patches were excised in darkness TRP remained closed, while when excised under illumination it stayed constitutively active. TRP was opened by DAG and silenced by ATP, suggesting DAG-kinase (DGK) involvement. The ATP effect was abolished by inhibiting DGK and in the rdgA mutant, lacking functional DGK, implicating DGK. DAG activated TRP even in the presence of a DAG-lipase inhibitor, inconsistent with a requirement of PUFAs in opening TRP. PIP2 had no effect and acidification, pH 6.4, activated TRP irreversibly, unlike the endogenous activator. Complementary liquid-chromatography/mass-spectrometry determinations of DAG and PUFAs in membranes enriched in rhabdomere obtained from light- and dark-adapted eyes showed light-dependent increment in six DAG species and no changes in PUFAs. The results strongly support DAG as the endogenous TRP agonist, as some of its vertebrate TRPC homologs of the same channel family. PMID:24806693

Delgado, Ricardo; Muñoz, Yorka; Peña-Cortés, Hugo; Giavalisco, Patrick; Bacigalupo, Juan

2014-05-01

264

Effects of hydroxyl radical scavengers KCN and CO on ultraviolet light-induced activation of crude soluble guanylate cyclase  

SciTech Connect

The crude soluble guanylate cyclase (GC) from bovine mesenteric artery was stimulated by ultraviolet (UV) light (366 nm). Addition of free radical scavengers, dimethylsulfoxide or superoxide dismutase and/or catalase to the GC assay did not abolish the stimulatory effect of UV light. On the contrary, the UV light-induced activation was enhanced in the presence of these scavengers. KCN (1 mM) did not affect the UV light-induced activation, while 0.1 mM of CO potentiated the activation. These results may indicate that UV light is operating through a direct interaction with the ferrous form of the GC-heme.

Karlsson, J.O.; Axelsson, K.L.; Andersson, R.G.

1985-01-01

265

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

266

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.

2006-03-01

267

Characterization and activity of visible-light driven TiO2 photocatalyst doped with tungsten.  

PubMed

This research aimed to expand the activity of TiO(2) down to the visible light region by modifying the sol-gel conditions and doping with tungsten. The optimum conditions for calcination temperature, acid type, and heating rate were 200°C, HNO(3), and 1°C/min, respectively. The undoped TiO(2) synthesized under these conditions could significantly absorb the visible light whereas the commercial Degussa P-25 could not. The absorptivity decreased sequentially as the wavelength increased from 400 to 700 nm. Within 6 h of 2-W blue-light illumination, 23% of 0.1 mM 2-chlorophenol was removed. The XRD result showed that the crystalline was anatase phase. The visible-light absorption property of the TiO(2) became even better when doped with tungsten. At the optimum W to TiO(2) ratio of 0.5%, the degradation of 0.1 mM 2-chlorophenol increased to 53% indicating a higher photocatalytic activity. Both crystalline and amorphous TiO(2) could exhibit the photocatalytic activity under the visible light region. PMID:21045341

Putta, T; Lu, M C; Anotai, J

2010-01-01

268

Anti-pollution and antifire floating barrier  

SciTech Connect

The barrier of this invention is formed by barrier sections and each of them can be wound up about a reel or bobbin, which is pivotably mounted within a main floating hollow element, which not only has the task of receiving, transporting, towing, launching and trawling the barrier section housed therein, but also it serves to provide anchoring points for this barrier. Each main barrier element is shaped in the form of a cage-like container provided with at least a side vertical entrance passage , through which a barrier section can be returned inside the container, or this section can be caused to come out, each main floating element thus serving as floating container for the transport of at least one of the barrier sections to or from their use place.

Bossa, E.D.

1981-07-21

269

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

270

Visible-Light Activities of Erbium Doped BiVO4 Photocatalysts  

NASA Astrophysics Data System (ADS)

Er-doped BiVO4 composite photocatalyst was hydrothermal synthesized and characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray Spectroscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectra techniques. The activity of the catalyst was determined by oxidative decomposition of methyl orange in aqueous solution under visible-light irradiation. X-ray photoelectron spectroscopy and energy-dispersive X-ray Spectroscopy analysis revealed that the doped Er existed in the form of Er2O3. It also showed that the Er doping can enhance the visible-light absorption abilities of catalysts and their visible-light-driven photocatalytic activities in comparison with those of pure BiVO4.

Zhang, Ai-ping; Zhang, Jin-zhi

2010-02-01

271

Energetic analysis of the white light emission associated to seismically active flares in solar cycle 24  

NASA Astrophysics Data System (ADS)

Solar flares are explosive phenomena, thought to be driven by magnetic free energy accumulated in the solar corona. Some flares release seismic transients, "sunquakes", into the Sun's interior. Different mechanisms are being considered to explain how sunquakes are generated. We are conducting an analysis of white-light emission associated with those seismically active solar flares that have been reported by different authors within the current solar cycle. Seismic diagnostics are based upon standard time-distance techniques, including seismic holography, applied to Dopplergrams obtained by SDO/HMI and GONG. The relation between white-light emissions and seismic activity may provide important information on impulsive chromospheric heating during flares, a prospective contributor to seismic transient emission, at least in some instances. We develop a method to get an estimation of Energy associated whit white-light emission and compare those results whit values of energy needed to generate a sunquake according with holographic helioseismology techniques.

Buitrago-Casas, Juan Camilo; Martinez Oliveros, Juan Carlos; Glesener, Lindsay; Krucker, Sam

2014-06-01

272

Light and Heavy Heterosexual Activities of Young Canadian Adolescents: Normative Patterns and Differential Predictors  

ERIC Educational Resources Information Center

The objectives of this research were to explore patterns of heterosexual activity in early adolescence and to examine the differential pathways to light and heavy heterosexuality. We utilized the National Longitudinal Survey of Canadian Children and Youth (NLSCY) in which heterosexual behaviors, as well as puberty, parenting processes, peer…

Williams, Trish; Connolly, Jennifer; Cribbie, Robert

2008-01-01

273

Slow-light enhancement of spontaneous emission in active photonic crystal waveguides  

NASA Astrophysics Data System (ADS)

Photonic crystal defect waveguides with embedded active layers containing single or multiple quantum wells or quantum dots have been fabricated. Spontaneous emission spectra are enhanced close to the bandedge, consistently with the enhancement of gain by slow light effects. These are promising results for future compact devices for terabit/s communication, such as miniaturised semiconductor optical amplifiers and mode-locked lasers.

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

2012-02-01

274

Effect of sprouting and light cycle on antioxidant activity of Brassica oleracea varieties.  

PubMed

The antioxidant activity of sprouts from four Brassica oleracea varieties was evaluated using "in vitro" methods (total phenolic and flavonoid content; radical scavenging assays: DPPH, hydroxyl and peroxyl; and Ferrous Ion-chelating Ability Assay). Light cycles and sprouting influenced the potential antioxidant activity of sprouts and significant differences were observed between varieties. Generally, antioxidant activity decreased with sprouting and increased in the presence of light, whose discriminant effect was highly significant (P<0.001). Red cabbage sprouts produced under light cycles showed the highest antioxidant activity (57.11?gmL(-1) Ferrous Ion-chelating Ability, 221.46?gmL(-1) Hydroxyl radical scavenging, 279.02?gmL(-1) Peroxyl radical scavenging). Among the traditional Portuguese brassica varieties, Penca cabbage sprouts produced under light presented higher antioxidant capacity, and also higher phenolic and flavonoid content (54.04mg GAEg(-1) d.w. extract and 21.33 QEg(-1) d.w. extract, respectively) than Galega kale. The phenolic content of Brassica sprouts had a significant contribution to the antioxidant capacity. PMID:25038690

Vale, Ana Paula; Cidade, Honorina; Pinto, Madalena; Oliveira, M Beatriz P P

2014-12-15

275

Optics: Light, Color, and Their Uses. An Educator's Guide With Activities In Science and Mathematics  

NASA Technical Reports Server (NTRS)

This document includes information on the Chandra X-Ray Observatory, the Hubble Space Telescope, the Next Generation Space Telescope, Soft X-Ray Imager, and the Lightning Imaging System. Classroom activities from grades K-12 are included, focusing on light and color, using mirrors, lenses, prisms, and filters.

2000-01-01

276

Visible light induced fast synthesis of protein-polymer conjugates: controllable polymerization and protein activity.  

PubMed

Herein visible light is used to induce RAFT polymerization from protein for preparing protein-polymer conjugates at ambient temperature. Polymerization is fast and can be conveniently controlled with irradiation time. By site-specific polymerization of NIPAm to protein, the protein activity is maintained and in certain cases it presents an efficient on-off-switchable property. PMID:24817595

Li, Xin; Wang, Lei; Chen, Gaojian; Haddleton, David M; Chen, Hong

2014-06-21

277

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

278

Floating Breakwaters: State-of-the-Art Literature Review.  

National Technical Information Service (NTIS)

A multitude of conceptual models of floating breakwaters have been proposed without extensive or complete evaluation of most of these concepts. The technical literature regarding floating breakwater applicability and design procedures is fragmentary and s...

L. Z. Hales

1981-01-01

279

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

280

A New Distillation Algorithm for Floating-Point Summation  

Microsoft Academic Search

The summation of n floating-point numbers is ubiquitous in numerical computations. We present a new distillation algorithm for floating-point summation which is stable, efficient, and accurate. The algorithm iteratively \\

Yong-Kang Zhu; Jun-Hai Yong; Guo-Qin Zheng

2005-01-01

281

Protective systems against active oxygen species in spinach: response to cold acclimation in excess light  

Microsoft Academic Search

Spinach (Spinacia oleracea L.) plants were acclimated to 1° C or maintained at 18° C under the same light regime (260–300 µmol photons·m-2·s-1). The cold acclimation led to several metabolic and biochemical changes that apparently include improved protection of the photosynthetic apparatus against active oxygen species. In particular, cold-acclimated leaves exhibited a considerably higher ascorbate content and significantly increased activities

Susanne Schöner; G. Heinrich Krause

1990-01-01

282

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

283

Astronaut Alfred Worden floats in space outside spacecraft during EVA  

NASA Technical Reports Server (NTRS)

Astronaut Alfred M. Worden, command module pilot of the Apollo 15 mission, floats in space outside of the spacecraft during his transearth extravehicular activity (EVA). This picture was taken from a frame of motion picture film exposed by the 16mm Maurer camera mounted on the hatch of the Command Module. During his EVA Worden made on inspection of the Service Module's Scientific Instrument Module (SIM) bay and retrieved the film cassettes from the Panoramic Camera and Mapping Camera. The EVA occurred when the spacecraft was homeward bound approximately 171,000 nautical miles from Earth.

1971-01-01

284

Effects of forward and backward transitions in light intensities in tau-illuminance curves of the rat motor activity rhythm under constant dim light.  

PubMed

Circadian rhythms are strongly influenced by light intensity, the effects of which may persist beyond the duration of light exposure (aftereffects). Here, the authors constructed period-illuminance curves for the motor activity circadian rhythm of male and female rats by recording the effects of a series of small upward and downward steps in light intensity (illuminance ranging between .01 lux of dim red light and 1 lux of white light) on their activity. In all cases, stepwise changes were made in five logarithmic steps (irradiance: dim red light: .692 µW/cm(2) and white light: .006, .016, .044, .12, and .315 µW/cm(2), corresponding, respectively, to .02, .05, .14, .13, and 1 lux measured at cage level), with changes in intensity every 2 wks. One group of rats (DLD) started in dim red light, moved up to 1 lux white light, and then back down to the original light intensity. Another group (LDL) started at 1 lux, moved down to .01 lux, and then back up to the original intensity. Motor activity data were recorded throughout the experiment and tau values, the percentage of variance explained by the rhythm, and the mean motor activity for each stage and group were calculated. The results show differences in the dynamics of tau values between the DLD and LDL groups and between males and females. In the LDL group, the tau values of both males and females were dependent on light intensity, and were similar for the forward and backward transitions. In other words, no aftereffects were found, and no differences were detected between males and females. In the DLD group, however, differences were found between males and females. Males had a tau value of 24 h 20 min under dim red light, 25 h 40 min under 1 lux, and 24 h 50 min on return to dim red light. It is noticeable that the tau values of the backward branch of the illuminance curve contradicted classical predictions, since at .38 and .14 lux the tau values were shorter than those found under the same intensities after exposure to 1 lux. Females became arrhythmic at 1 lux, and only one half of them recovered their circadian rhythm at .02 lux. The other one half remained arrhythmic even under dim red light. Thus, some of the results of this paper contradict the predictions of standard descriptions of the functioning of the circadian clock, possibly due to the effects of dim light. PMID:22734570

Cambras, Trinitat; Díez-Noguera, Antoni

2012-07-01

285

Design Issues in Division and Other Floating-Point Operations  

Microsoft Academic Search

Floating-point division is generally regarded as a low frequency, high latency operation in typical floating-pointapplications. However, in the worst case, a high latency hardware floating-point divider can contribute an additional 0.50 CPI to asystem executing SPECfp92 applications. This paper presents the system performance impact of floating-point division latency forvarying instruction issue rates. It also examines the performance implications of shared

Stuart F. Oberman; Michael J. Flynn

1997-01-01

286

Leishmania tropica: the effect of darkness and light on biological activities in vitro.  

PubMed

Leishmania parasites can be exposed to effects of light in their vectors and hosts, at various periods. However, there is no information about the effects of light on Leishmania parasites. The aim of this study is to investigate the effects of light on various cell parameters of Leishmania tropica, in vitro. All experiments were conducted on L. tropica promastigotes and amastigote-macrophage cultures, using flow cytometric analysis, MTT and phenol-sulfuric acid assay, DAPI and Giemsa. The results showed that the morphology of parasites has changed; the cell cycle has been affected and this caused parasites to remain at G0/G1 phase. Furthermore the proliferation, infectivity, glucose consumption and mitochondrial dehydrogenase activities of parasites were decreased. Thus, for the first time, in this study, the effects of light on biological activities of Leishmania parasites were shown. These new information about parasites' biology, would be very important to investigate the effects of light on the parasites in infected vectors and hosts. PMID:21510933

Allahverdiyev, Adil M; Koc, Rabia Cakir; Ates, Sezen Canim; Bagirova, Malahat; Elcicek, Serhat; Oztel, Olga Nehir

2011-08-01

287

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.

2013-01-01

288

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

289

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

290

In Vivo Blue-Light Activation of Chlamydomonas reinhardii Nitrate Reductase 1  

PubMed Central

Chlamydomonas reinhardii cells, growing photoautotrophically under air, excreted to the culture medium much higher amounts of NO2? and NH4+ under blue than under red light. Under similar conditions, but with NO2? as the only nitrogen source, the cells consumed NO2? and excreted NH4+ at similar rates under blue and red light. In the presence of NO3? and air with 2% CO2 (v/v), no excretion of NO2? and NH4+ occurred and, moreover, if the bubbling air of the cells that were currently excreting NO2? and NH4+ was enriched with 2% CO2 (v/v), the previously excreted reduced nitrogen ions were rapidly reassimilated. The levels of total nitrate reductase and active nitrate reductase increased several times in the blue-light-irradiated cells growing on NO3? under air. When tungstate replaced molybdate in the medium (conditions that do not allow the formation of functional nitrate reductase), blue light activated most of the preformed inactive enzyme of the cells. Furthermore, nitrate reductase extracted from the cells in its inactive form was readily activated in vitro by blue light. It appears that under high irradiance (90 w m?2) and low CO2 tensions, cells growing on NO3? or NO2? may not have sufficient carbon skeletons to incorporate all the photogenerated NH4+. Because these cells should have high levels of reducing power, they might use NO3? or, in its absence, NO2? as terminal electron acceptors. The excretion of the products of NO2? and NH4+ to the medium may provide a mechanism to control reductant level in the cells. Blue light is suggested as an important regulatory factor of this photorespiratory consumption of NO3? and possibly of the whole nitrogen metabolism in green algae.

Azuara, Maria Pilar; Aparicio, Pedro J.

1983-01-01

291

Improving the performance of floating solar pool covers  

SciTech Connect

Experimental and analytical analyses are presented for the evaluation of heat transfer through floating solar swimming pool covers. Two improved floating solar swimming pool cover designs are proposed and investigated in this paper. The results conclusively show that both new cover designs should have significantly better performance than conventional floating solar swimming pool covers.

Cole, M.A.; Lowrey, P. (San Diego State Univ., CA (United States). Dept. of Mechanical Engineering)

1992-11-01

292

40 CFR 63.1043 - Standards-Separator floating roof.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false Standards-Separator floating roof. 63.1043 Section 63.1043... § 63.1043 StandardsâSeparator floating roof. (a) This section applies...separator or organic-water separator using a floating roof. (b) The separator shall...

2009-07-01

293

40 CFR 63.1063 - Floating roof requirements.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Floating roof requirements. 63.1063 Section...Control Level 2 § 63.1063 Floating roof requirements. The owner or operator who elects to use a floating roof to comply with the...

2010-07-01

294

40 CFR 63.1063 - Floating roof requirements.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Floating roof requirements. 63.1063 Section...Control Level 2 § 63.1063 Floating roof requirements. The owner or operator who elects to use a floating roof to comply with the...

2013-07-01

295

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false External floating roof (EFR). 65.44 Section 65...Storage Vessels § 65.44 External floating roof (EFR). (a) EFR design requirements...material emissions by using an external floating roof shall comply with the design...

2013-07-01

296

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false External floating roof (EFR). 65.44 Section 65...Storage Vessels § 65.44 External floating roof (EFR). (a) EFR design requirements...material emissions by using an external floating roof shall comply with the design...

2009-07-01

297

40 CFR 65.44 - External floating roof (EFR).  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false External floating roof (EFR). 65.44 Section 65...Storage Vessels § 65.44 External floating roof (EFR). (a) EFR design requirements...material emissions by using an external floating roof shall comply with the design...

2010-07-01

298

40 CFR 63.1043 - Standards-Separator floating roof.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Standards-Separator floating roof. 63.1043 Section 63.1043... § 63.1043 StandardsâSeparator floating roof. (a) This section applies...separator or organic-water separator using a floating roof. (b) The separator shall...

2013-07-01

299

40 CFR 63.1043 - Standards-Separator floating roof.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false Standards-Separator floating roof. 63.1043 Section 63.1043... § 63.1043 StandardsâSeparator floating roof. (a) This section applies...separator or organic-water separator using a floating roof. (b) The separator shall...

2010-07-01

300

40 CFR 63.1063 - Floating roof requirements.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 2009-07-01 false Floating roof requirements. 63.1063 Section...Control Level 2 § 63.1063 Floating roof requirements. The owner or operator who elects to use a floating roof to comply with the...

2009-07-01

301

An Accelerator for Double Precision Floating Point Operations  

Microsoft Academic Search

We describe DPFPA (double precision floating point accelerator) an FPGA based coprocessor interfaced to the CPU through the PCI bus; it is conceived to accelerate the evaluation of double precision floating point operations. This coprocessor is based on two double precision floating point units: a pipelined adder and a pipelined multiplier. The work is part of a global project aimed

Giovanni Danese; Ivo De Lotto; Francesco Leporati; M. Scaricabarozzi; Alvaro Spelgatti

2003-01-01

302

14 CFR 25.535 - Auxiliary float loads.  

Code of Federal Regulations, 2010 CFR

...load must be applied in the plane of symmetry of the float at a point three-fourths...the center of gravity and the plane of symmetry of the float to the radius of gyration...load must be applied in the plane of symmetry of the float at a point...

2009-01-01

303

14 CFR 25.535 - Auxiliary float loads.  

Code of Federal Regulations, 2010 CFR

...load must be applied in the plane of symmetry of the float at a point three-fourths...the center of gravity and the plane of symmetry of the float to the radius of gyration...load must be applied in the plane of symmetry of the float at a point...

2010-01-01

304

14 CFR 23.535 - Auxiliary float loads.  

Code of Federal Regulations, 2010 CFR

...load must be applied in the plane of symmetry of the float at a point three-fourths...the center of gravity and the plane of symmetry of the float to the radius of gyration...load must be applied in the plane of symmetry of the float at a point...

2009-01-01

305

14 CFR 23.535 - Auxiliary float loads.  

Code of Federal Regulations, 2010 CFR

...load must be applied in the plane of symmetry of the float at a point three-fourths...the center of gravity and the plane of symmetry of the float to the radius of gyration...load must be applied in the plane of symmetry of the float at a point...

2010-01-01

306

Light activation and molecular-mass changes of NAD(P)-glyceraldehyde 3-phosphate dehydrogenase of spinach and maize leaves  

Microsoft Academic Search

Light modulation of chloroplast glyceraldehyde 3-phosphate dehydrogenase (NAD(P)-GAPDH; EC 1.2.1.13) has been investigated. Complete activation of NADPH-dependent activity is achieved at 25 W.m-2 photosynthetically active radiation in spinach (Spinacia oleracea L.) and 100 W.m-2 in maize (Zea mays L.) leaves. Light activation is stronger in spinach (fivefold on average) than in maize (twofold), which shows higher “dark” activity. The NADH

Sandra Scagliarini; Paolo Trost; Paolo Pupillo; Vincenzo Valenti

1993-01-01

307

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

308

One to eight month X-ray light curves for active extragalactic objects  

NASA Astrophysics Data System (ADS)

Light curves of 4 extragalactic objects obtained using the 0.5 to 20 keV LASS detectors on HEAO 1 are presented. Two of the objects are quasi-stellar sources; one is a BL Lacertae object; the fourth, although not unambiguously identified, is certainly extragalactic. In each case the light curves have a temporal resolution of a few days, and (because the sources are located at high ecliptic latitudes) extend at least 30 days in length. Variability is definitely detected in 3 of the 4 objects, suggesting that significant changes in flux may be common in active galaxies on monthly time scales.

Snyder, W.

1984-10-01

309

High-efficiency white organic light-emitting diodes using thermally activated delayed fluorescence  

NASA Astrophysics Data System (ADS)

White organic light-emitting diodes (WOLEDs) have attracted much attention recently, aimed for next-generation lighting sources because of their high potential to realize high electroluminescence efficiency, flexibility, and low-cost manufacture. Here, we demonstrate high-efficiency WOLED using red, green, and blue thermally activated delayed fluorescence materials as emissive dopants to generate white electroluminescence. The WOLED has a maximum external quantum efficiency of over 17% with Commission Internationale de l'Eclairage coordinates of (0.30, 0.38).

Nishide, Jun-ichi; Nakanotani, Hajime; Hiraga, Yasuhide; Adachi, Chihaya

2014-06-01

310

Light-Inducible Spatiotemporal Control of Gene Activation by Customizable Zinc Finger Transcription Factors  

PubMed Central

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.

2012-01-01

311

Subharmonic and Divergent Motions of Floating Platforms.  

National Technical Information Service (NTIS)

Motions of 1/100 and 1/30 scale models of column-stabilized floating platforms in regular waves have been found to fall in two categories: where heave, surge, and pitch motions are in synchronism with the waves, and where major motions are at subharmonic ...

D. Bellows

1973-01-01

312

Floating Tire Breakwater Tests Pickering Beach, Delaware.  

National Technical Information Service (NTIS)

This report documents a 1-week long field monitoring effort conducted at Pickering Beach, Delaware. The purpose of the study was to gain information concerning mooring line response of a floating breakwater subjected to boat-generated waves. Data are comp...

P. J. Grace J. E. Clausner

1987-01-01

313

Residents' perceptions of a night float system  

Microsoft Academic Search

BACKGROUND: A Night Float (NF) system has been implemented by many institutions to address increasing concerns about residents' work hours. The purpose of our study was to examine the perceptions of residents towards a NF system. METHODS: A 115-item questionnaire was developed to assess residents' perceptions of the NF rotation as compared with a regular call month. The categories included

Harish Jasti; Barbara H Hanusa; Galen E Switzer; Rosanne Granieri; Michael Elnicki

2009-01-01

314

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

315

Managed Floating as a Monetary Policy Strategy  

Microsoft Academic Search

Although there seems to be a broad consensus among economists that purely floating or completely fixed exchange rates (the so-called corner solutions) are the only viable alternatives of exchange rate management, many countries do not behave according to this paradigm and adopt a strategy within the broad spectrum of exchange rate regimes that is limited by the two corner solutions.

Peter Bofinger; Timo Wollmershäuser

2003-01-01

316

Floating roof tank with rim space seal  

Microsoft Academic Search

This patent describes a vertical cylindrical liquid storage tank having a circular floating roof of smaller diameter than the tank thereby defining a clearance space between the roof edge and the tank wall; a seal joined to the roof and extending upwardly therefrom into slidable contact with the tank wall; the seal completely covering the clearance space; the seal comprising

R. B. Grove; S. W. Peters; M. L. Tellalian

1986-01-01

317

Development of a Mixed Layer Float.  

National Technical Information Service (NTIS)

The purpose of this grant was to finish development of a new type of neutrally buoyant float designed to accurately follow the three dimensional motion of water parcels in the ocean mixed layer. This work was joint with David Farmer, of the Institute of O...

E. A. D'Asaro

1993-01-01

318

The Accuracy of Floating Point Summation  

Microsoft Academic Search

. The usual recursive summation technique is just one of several ways of computing thesum of n floating point numbers. Five summation methods and their variations are analysed here.The accuracy of the methods is compared using rounding error analysis and numerical experiments.Four of the methods are shown to be special cases of a general class of methods, and an error

Nicholas J. Higham

1993-01-01

319

Adaptive floating search methods in feature selection  

Microsoft Academic Search

Abstract A new,suboptimal,search strategy for feature selection is presented. It represents a more,sophisticated version of ‘‘classical’’ floating search algorithms (Pudil et al., 1994), attempts to remove some of their potential deficiencies and facilitates finding a solution even closer to the optimal,one. ” 1999 Elsevier Science B.V. All rights reserved. Keywords: Pattern recognition; Feature selection; Search methods

Petr Somol; Pavel Pudil; Jana Novovicová; Pavel Paclík

1999-01-01

320

Error analysis of floating-point computation  

Microsoft Academic Search

This paper consists of two main sections. In the first the bounds are derived for the rounding errors made in the fundamental floating-point arithmetic operations. In the second, these results are applied in the analysis of a number of computing techniques for the calculation of the eigenvalues of matrices. In each case thecomputed solution is expressed as the exact solution

J. H. Wilkinson

1960-01-01

321

Robust adaptive floating-point geometric predicates  

Microsoft Academic Search

Fast C implementations of four geometric predicates, the 2D and 3D orientation and incircle tests, are publicly avail- able. Their inputs are ordinary single or double precision floating-point numbers. They owe their speed to two fea- tures. First, they employ new fast algorithms for arbitrary precision arithmetic that have a strong advantage over other software techniques in computations that manipulate

Johnathan Richard Shewchuk

1996-01-01

322

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

323

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

324

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

325

[Preparation and characterization of visible-light response activated carbon with antibacterial behavior].  

PubMed

A visible-light response activated carbon with antibacterial activity was prepared by calcinations of the mixture of TiO2 precursor obtained by acid catalyzed hydrolysis method and commercial granular activated carbon (GAC) in NH3/N2 atmosphere. The antibacterial activity of the prepared activated carbon towards E. coil was investigated under the visible-light irradiation. X-ray diffraction (XRD), Scanning electron spectroscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and N2 adsorption analyser were used to characterize the crystal phase structure, surface morphology, spectral characteristics and pore properties. The results show there is no influence for crystal phase structure of TiO2 supported AC. The crystal size of TiO2 is 9.8 nm. Non-crystal phase layer and strong adsorption force of carrier can inhibit the grain growth of TiO2, and AC combines with TiO2 in Ti-O-C so that TiO2 formestight film on AC. The sample calcinated at 500 degrees C for 5 h exhibits the highest bactericidal performance, and the bactericidal rate reached up to 67% after 4 h irradiation, which was better than that of nature light (39%) in the same condition. PMID:21404678

Zhang, Hui-Shu; Wang, Zi-Qiang; Wang, Rui; Liu, Shou-Xin

2011-01-01

326

Mössbauer spectra of tin in float glass  

NASA Astrophysics Data System (ADS)

Tin is not a major constituent of window glass, but is found at high concentrations in the lower surface of float glass which has been in contact with the molten tin bath. It does not extend far into the surface, but causes the physical and chemical behaviour to differ from that of the upper surface. It is important, therefore, to understand the structural role of tin in silicate glasses and thus its effect on various properties. Mössbauer spectra were taken of three series of glassy materials, namely binary glasses (SnO and SiO2) in varying proportions, re-melted float glass containing tin, and float glass from a production plant. The binary glasses contained between 20 and 70% tin which was found to be mainly Sn2+, with very small amounts of Sn4+ in some of them. The spectra showed a small decrease in isomer shift with increase in tin content, which is ascribed to the change in molar volume. The re-melted samples were float glass which was mixed with stannous oxalate in appropriate conditions to try and maintain tin in the 2+ state, and contained up to 15% tin by weight. The spectra show both Sn4+ and Sn2+ with rather more in the 4+ oxidation state. The change in the spectra as a function of temperature revealed a large difference in the f-factor (and hence the chemical binding) of the two states. A series of spectra was taken between 17.5 and 900 K for the sample containing 15% tin. From the absorption as a function of temperature the f-factor was determined for both oxidation states, and hence enabled the relative amounts of Sn4+ and Sn2+ present in each sample to be estimated. Measurements of the shift as a function of temperature were also made. The float samples were surface material produced by grinding away all but 0.1 mm of the lower surface of industrially produced float glass. The Mössbauer spectra showed them to be predominantly Sn2+, as expected from the reducing atmosphere in the float plant. The concentration and oxidation state of the tin may be estimated from the value of the f-factors and isomer shifts.

Johnson, J. A.; Johnson, C. E.; Williams, K. F. E.; Holland, D.; Karim, M. M.

1995-12-01

327

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.

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

2014-01-01

328

Carbon nanotube active-matrix backplanes for mechanically flexible visible light and X-ray imagers.  

PubMed

We report visible light and X-ray imagers on lightweight and mechanically flexible plastic substrates. The process involves solution processing of organic photodetectors on top of an active-matrix backplane consisting of carbon nanotube thin-film transistors. The system takes advantage of the high mobility of nanotube transistors for low operating voltages and efficient light absorption of organic bulk-heterojunctions for high imaging sensitivity. With this highly scalable process scheme, 18 × 18 pixel-array flexible imagers (physical size of 2 cm × 1.5 cm) with high performance are successfully demonstrated. In addition, as the absorption peak of the adopted organic photodiodes covers the green band of the light spectrum, X-ray imaging is readily demonstrated by placing a scintillator film on top of the flexible imagers. PMID:24143966

Takahashi, Toshitake; Yu, Zhibin; Chen, Kevin; Kiriya, Daisuke; Wang, Chuan; Takei, Kuniharu; Shiraki, Hiroshi; Chen, Teresa; Ma, Biwu; Javey, Ali

2013-01-01

329

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

330

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.

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

2014-01-01

331

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

332

Light Source  

Microsoft Academic Search

Bioelectromagnetics\\/resonance effect Using a Synchroton Light source to probe brain mechanism This paper suggests that photons or instantons from a Synchrotron light source, activates brain cells, which because of membrane polaribility can receive light. It explains how synchrotron radiation can pentrate and activate cells,and thus serve as an excellent probe of brain mechanisms. Wavelengths the broad range of synchrotron light

Jane Krakower

2000-01-01

333

Blue-light-activated phototropin2 trafficking from the cytoplasm to Golgi/post-Golgi vesicles  

PubMed Central

Phototropins are plasma membrane-localized UVA/blue light photoreceptors which mediate phototropism, inhibition of primary hypocotyl elongation, leaf positioning, chloroplast movements, and stomatal opening. Blue light irradiation activates the C-terminal serine/threonine kinase domain of phototropin which autophosphorylates the receptor. Arabidopsis thaliana encodes two phototropins, phot1 and phot2. In response to blue light, phot1 moves from the plasma membrane into the cytosol and phot2 translocates to the Golgi complex. In this study the molecular mechanism and route of blue-light-induced phot2 trafficking are demonstrated. It is shown that Atphot2 behaves in a similar manner when expressed transiently under 35S or its native promoter. The phot2 kinase domain but not blue-light-mediated autophosphorylation is required for the receptor translocation. Using co-localization and western blotting, the receptor was shown to move from the cytoplasm to the Golgi complex, and then to the post-Golgi structures. The results were confirmed by brefeldin A (an inhibitor of the secretory pathway) which disrupted phot2 trafficking. An association was observed between phot2 and the light chain2 of clathrin via bimolecular fluorescence complementation. The fluorescence was observed at the plasma membrane. The results were confirmed using co-immunoprecipitation. However, tyrphostin23 (an inhibitor of clathrin-mediated endocytosis) and wortmannin (a suppressor of receptor endocytosis) were not able to block phot2 trafficking, indicating no involvement of receptor endocytosis in the formation of phot2 punctuate structures. Protein turnover studies indicated that the receptor was continuously degraded in both darkness and blue light. The degradation of phot2 proceeded via a transport route different from translocation to the Golgi complex.

Aggarwal, Chhavi; Banas, Agnieszka Katarzyna; Kasprowicz-Maluski, Anna; Borghetti, Carolina; Labuz, Justyna; Dobrucki, Jerzy; Gabrys, Halina

2014-01-01

334

Blue-light-activated phototropin2 trafficking from the cytoplasm to Golgi/post-Golgi vesicles.  

PubMed

Phototropins are plasma membrane-localized UVA/blue light photoreceptors which mediate phototropism, inhibition of primary hypocotyl elongation, leaf positioning, chloroplast movements, and stomatal opening. Blue light irradiation activates the C-terminal serine/threonine kinase domain of phototropin which autophosphorylates the receptor. Arabidopsis thaliana encodes two phototropins, phot1 and phot2. In response to blue light, phot1 moves from the plasma membrane into the cytosol and phot2 translocates to the Golgi complex. In this study the molecular mechanism and route of blue-light-induced phot2 trafficking are demonstrated. It is shown that Atphot2 behaves in a similar manner when expressed transiently under 35S or its native promoter. The phot2 kinase domain but not blue-light-mediated autophosphorylation is required for the receptor translocation. Using co-localization and western blotting, the receptor was shown to move from the cytoplasm to the Golgi complex, and then to the post-Golgi structures. The results were confirmed by brefeldin A (an inhibitor of the secretory pathway) which disrupted phot2 trafficking. An association was observed between phot2 and the light chain2 of clathrin via bimolecular fluorescence complementation. The fluorescence was observed at the plasma membrane. The results were confirmed using co-immunoprecipitation. However, tyrphostin23 (an inhibitor of clathrin-mediated endocytosis) and wortmannin (a suppressor of receptor endocytosis) were not able to block phot2 trafficking, indicating no involvement of receptor endocytosis in the formation of phot2 punctuate structures. Protein turnover studies indicated that the receptor was continuously degraded in both darkness and blue light. The degradation of phot2 proceeded via a transport route different from translocation to the Golgi complex. PMID:24821953

Aggarwal, Chhavi; Bana?, Agnieszka Katarzyna; Kasprowicz-Malu?ki, Anna; Borghetti, Carolina; Labuz, Justyna; Dobrucki, Jerzy; Gabry?, Halina

2014-07-01

335

Activation of retinal tyrosine hydroxylase: tolerance induced by chronic treatment with haloperidol does not modify response to light  

SciTech Connect

A single dose of haloperidol administered to rats in the dark increases the activity of retinal tyrosine hydroxylase. The ability of haloperidol to activate the enzyme is diminished 24 hr after terminating 22 to 30 days of treatment with haloperidol. The retinal enzyme is also tolerant to activation by treatment with chlorpromazine. In contrast, exposure of the animals to light activates the enzyme to the same extent in chronic haloperidol-treated and control animals. Thus, chronic haloperidol treatment does not modify the ability of the retinal enzyme system to respond to the physiological stimulus, light. Apparently, activation of retinol tyrosine hydroxylase by haloperidol and light occurs by independent mechanisms.

Cohen, J.; Neff, N.H.

1982-05-01

336

Light Intensity and Carbon Dioxide Availability Impact Antioxidant Activity in Green Onions (Allium fistulosumm L)  

NASA Astrophysics Data System (ADS)

The prospect of long-duration manned space missions poses many challenges, including the development of a sustainable life support system and effective methods of space-radiation protection. To mitigate the risk of increased space-radiation, functional foods rich in antioxidant properties such as green onions are of particular interest. However it has yet to be established whether antioxidant properties can be preserved or enhanced in space environment where carbon dioxide, lighting intensity, gravity and pressure differ from which plants have acclimated to on earth. In this study, green onions (Allium fistulosumm L. cultivar Kinka) rich in antioxidant flavonoids are used as a model system to investigate variations in antioxidant capacity with plants grown under varying light intensities and CO2 concentrations. The antioxidant potential is determined using both radical cation scavenging and oxygen radical absorbance assays. For all light intensities assayed, antioxidant potential in water extract of green onions per gram biomass declined with CO2 increases up to 1200 ppm, and then leveled off with further CO2 increase to 4000 ppm. This inverse carbon dioxide versus antioxidant activity correlation suggests lower accumulation rates for water soluble antioxidant compounds compared to total biomass under increasing CO2 concentrations. The effect of increasing atmospheric CO2 concentration on antioxidant activity of ethanol extracts were light intensity dependent. The implications of these findings are discussed in the context of traditional plant antioxidants including vitamin C and the major onion flavonoid quercetin.

Levine, Lanfang; Bisbee, Patricia; Pare, Paul

337

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.

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

2011-01-01

338

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.

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

2013-01-01

339

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

340

On the Assimilation of Argo Float Trajectories into the Mediterranean Forecasting System  

NASA Astrophysics Data System (ADS)

The Mediterranean Forecasting System (MFS) has been in operations for nearly a decade, and it is continuously providing analyses on a weekly basis for the region. These forecasts are of great importance as they provide local and basin-scale information of the environmental state of the sea, and are also highly useful for tracking oil spill and search-and-rescue missions. The circulation in the interior Mediterranean Sea is to a large extent characterized by meso-scale eddies, which often have proved somewhat difficult to simulate in an adequate manner due to their high temporal and spatial variability. Data assimilation is a widely used method to improve the forecast skill of operational models and, in this study, the three-dimensional variational (OceanVAR) scheme has been extended to include Argo float trajectories, with the objective to constrain and ameliorate the numerical output primarily in terms of the subsurface velocity fields. The method of implementing the float positions into the cost function is highly unique, since it uses a tangent-linear trajectory model as the observational operator. The modeled float trajectories are obtained by integration of the linearized particle advection equation during 5-day periods, corresponding to the time when the Argo floats are drifting at parking depth (350m). For the first time, basin-wide numerical experiments have been undertaken for a 3-year period (2005-2007), and it was concluded that the trajectory assimilation significately improves the simulation of Argo float trajectories based upon analyses. Indeed, statistical studies of the root-mean-square differences between the observed and analysed float positions showed that the new OceanVar scheme yields ~20% better estimates of the predicted ocean currents. It was furthermore established that the extended OceanVAR scheme does not compromise the forecast/analysis quality of the other state variables (e.g. SLAs, temperature, salinity). A notable decrease in availability of Argo-float data was noted during the period, with the maximum amount and spread of floats in 2005. The impact of the fall-off in float abundance was studied in terms of analyses, and implications on the operational activities will be pointed out.

Nilsson, Jenny A. U.; Dobricic, Srdjan; Taillandier, Vincent; Poulain, Pierre-Marie; Pinardi, Nadia

2010-05-01

341

Nickel(II) oxide surface-modified titanium(IV) dioxide as a visible-light-active photocatalyst.  

PubMed

The electronic modification of TiO(2) with highly dispersed NiO particles smaller than ca. 2 nm by the chemisorption-calcination-cycle technique has given rise to a high level of visible-light-activity exceeding that of iron oxide-surface modified TiO(2) simultaneously with the UV-light-activity being significantly increased. PMID:21738923

Jin, Qiliang; Ikeda, Takuro; Fujishima, Musashi; Tada, Hiroaki

2011-08-21

342

Photochemical activities and organization of photosynthetic apparatus of C 3 and C 4 plants grown under different light intensities  

Microsoft Academic Search

Changes in the photochemical activities, influenced by variation in the growth light intensity, were followed in typical C3 (Phaseolus, Ipomoea) and C4 (Amaranthus, Sorghum) plants. Progressive decrease in the growth light intensity accelerated the O-P fluorescence induction in whole leaves. Such acceleration of the fluorescence kinetics was found to be not due to enhanced photosystem II activity but possibly a

P. Sampath; G. Kulandaivelu

1983-01-01

343

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

344

Clay Float: Exploring Archimedesâ Principle  

NSDL National Science Digital Library

In this hands-on activity, learners explore Archimedes' Principle (buoyancy) by measuring the water displaced by clay balls. The lesson plan contains Texas science standards (TEKS), background information, key vocabulary, materials, procedures, questions to ask, extensions, and additional resources. This activity can be used on its own or combined with a visit to the FlowWorks exhibit at the Children's Museum of Houston.

Houston, Children'S M.

2008-01-01

345

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

2014-05-28

346

Relationship between the degree of conversion and internal discoloration of light-activated composite.  

PubMed

In order to elucidate the relationship between the degree of conversion and internal discoloration of light-activated composite, four experimental composites which contained different amounts of Bis-GMA and TEGDMA were prepared, and the degree of conversion and discoloration of each composite, with or without annealing, were determined. The degree of conversion was measured by Fourier transformation infrared spectroscopy and the color change was determined after 1, 2, 3 and 4 weeks of immersion in water at 60 degrees C. The non-annealed composites demonstrated a greater degree of conversion and less discoloration as the amount of TEGDMA was increased. Annealed composites showed a significantly greater degree of conversion and less discoloration compared with the non-annealed composites. The results indicate that the greater the degree of conversion, the less the discoloration of composite, and the correlation between the two factors was significant for light-activated composite. PMID:8940542

Imazato, S; Tarumi, H; Kobayashi, K; Hiraguri, H; Oda, K; Tsuchitani, Y

1995-06-01

347

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.

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

2014-01-01

348

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

349

Theoretical studies of floating-reference method for NIR blood glucose sensing  

NASA Astrophysics Data System (ADS)

Non-invasive blood glucose monitoring using NIR light has been suffered from the variety of optical background that is mainly caused by the change of human body, such as the change of temperature, water concentration, and so on. In order to eliminate these internal influence and external interference a so called floating-reference method has been proposed to provide an internal reference. From the analysis of the diffuse reflectance spectrum, a position has been found where diffuse reflection of light is not sensitive to the glucose concentrations. Our previous work has proved the existence of reference position using diffusion equation. However, since glucose monitoring generally use the NIR light in region of 1000-2000nm, diffusion equation is not valid because of the high absorption coefficient and small source-detector separations. In this paper, steady-state high-order approximate model is used to further investigate the existence of the floating reference position in semi-infinite medium. Based on the analysis of different optical parameters on the impact of spatially resolved reflectance of light, we find that the existence of the floating-reference position is the result of the interaction of optical parameters. Comparing to the results of Monte Carlo simulation, the applicable region of diffusion approximation and higher-order approximation for the calculation of floating-reference position is discussed at the wavelength of 1000nm-1800nm, using the intralipid solution of different concentrations. The results indicate that when the reduced albedo is greater than 0.93, diffusion approximation results are more close to simulation results, otherwise the high order approximation is more applicable.

Shi, Zhenzhi; Yang, Yue; Zhao, Huijuan; Chen, Wenliang; Liu, Rong; Xu, Kexin

2011-02-01

350

Punch through float-zone silicon phototransistors with high linearity and sensitivity  

Microsoft Academic Search

In this paper, we propose, analyze and demonstrate a high-purity float-zone (FZ) silicon phototransistor operating at the punch through state with high linearity and sensitivity. Those phototransistors were fabricated on high-purity FZ silicon substrates; the dependence of the sensitivity on incident optical power and bias voltages has been investigated to light with a wavelength of 0.83 mum from a laser

C. M. Sun; D. J. Han; L. Y. Sheng; X. R. Zhang; H. J. Zhang; R. Yang; L. Zhang; B. J. Ning

2005-01-01

351

Punch through float-zone silicon phototransistors with high linearity and sensitivity  

Microsoft Academic Search

In this paper, we propose, analyze and demonstrate a high-purity float-zone (FZ) silicon phototransistor operating at the punch through state with high linearity and sensitivity. Those phototransistors were fabricated on high-purity FZ silicon substrates; the dependence of the sensitivity on incident optical power and bias voltages has been investigated to light with a wavelength of 0.83?m from a laser diode.

C. M. Sun; D. J. Han; L. Y. Sheng; X. R. Zhang; H. J. Zhang; R. Yang; L. Zhang; B. J. Ning

2005-01-01

352

Augmenting the Antibiofilm Efficacy of Advanced Noninvasive Light Activated Disinfection with Emulsified Oxidizer and Oxygen Carrier  

Microsoft Academic Search

In this study, we tested the hypothesis that the inclusion of an oxidizer and oxygen carrier in the photosensitization formulation would facilitate comprehensive disinfection of matured endodontic biofilm by light-activated disinfection (LAD). Photosensitizing formulations containing methylene blue (MB) and an oxygen carrier alone (perfluorodecahydronaphthalene) (PF1) or in combination with oxidizer (H2O2) (PF2) or their emulsions formed with triton-X100 (Bio-Rad Laboratories,

Saji George; Anil Kishen

2008-01-01

353

Visible-Light Activities of Erbium Doped BiVO4 Photocatalysts  

Microsoft Academic Search

Er-doped BiVO4 composite photocatalyst was hydrothermal synthesized and characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray Spectroscopy, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectra techniques. The activity of the catalyst was determined by oxidative decomposition of methyl orange in aqueous solution under visible-light irradiation. X-ray photoelectron spectroscopy and energy-dispersive X-ray Spectroscopy analysis revealed that the doped Er

Ai-ping Zhang; Jin-zhi Zhang

2010-01-01

354

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

Microsoft Academic Search

Antifungal activity of TiO2\\/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. TiO2 nanoparticles were deposited on ZnO nanowires using an atmospheric pressure chemical vapor deposition system. X-ray diffraction pattern of TiO2\\/ZnO nano-composite has represented

N. Haghighi; Y. Abdi; F. Haghighi

2011-01-01

355

Dynein light chain 1, a p21-activated kinase 1-interacting substrate, promotes cancerous phenotypes  

Microsoft Academic Search

We identified dynein light chain 1 (DLC1) as a physiologic substrate of p21-activated kinase 1 (Pak1). Pak1-DLC1 interaction plays an essential role in cell survival, which depends on Pak1's phosphorylation of DLC1 on Ser88. Pak1 associates with the complex of DLC1 and BimL, a proapoptotic BH3-only protein, and phosphorylates both proteins. Phosphorylation of BimL by Pak1 prevents it from interacting

Ratna K Vadlamudi; Rozita Bagheri-Yarmand; Zhibo Yang; Seetharaman Balasenthil; Diep Nguyen; Aysegul A Sahin; Petra den Hollander; Rakesh Kumar

2004-01-01

356

Studies on the photocatalytic performance of cuprous oxide\\/chitosan nanocomposites activated by visible light  

Microsoft Academic Search

Taking the chitosan nanoparticles prepared by adding only sodium sulfate into acetic acid solution of chitosan as carriers, cuprous oxide\\/chitosan nanocomposites were prepared by electrochemical deposition. It’s found that the needle shaped cuprous oxide nanocrystallines are combined with chitosan particles by chelation. Activated by a visible light, Cu2O\\/chitosan nanocomposites are used as a photocatalyst in the degradation of brilliant red

Jin-Yi Chen; Pei-Jiang Zhou; Jia-Lin Li; Yan Wang

2008-01-01

357

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

358

The Drosophila Light-Activated Conductance Is Composed of the Two Channels TRP and TRPL  

Microsoft Academic Search

Drosophila phototransduction is a G protein–coupled, calcium-regulated signaling cascade that serves as a model system for the dissection of phospholipase C (PLC) signaling in vivo. The Drosophila light-activated conductance is constituted in part by the transient receptor potential (trp) ion channel, yet trp mutants still display a robust response demonstrating the presence of additional channels. The transient receptor potential-like (trpl)

Barbara A Niemeyer; Emiko Suzuki; Kristin Scott; Kees Jalink; Charles S Zuker

1996-01-01

359

Low Temperature Polycrystalline Silicon Thin Film Transistor Pixel Circuits for Active Matrix Organic Light Emitting Diodes  

Microsoft Academic Search

A new pixel design and driving method for active matrix organic light emitting diode (AMOLED) displays that use low-temperature polycrystalline silicon thin-film transistors (LTPS-TFTs) with a voltage programming method are proposed and verified using the SPICE simulator. We had employed an appropriate TFT model in SPICE simulation to demonstrate the performance of the pixel circuit. The OLED anode voltage variation

Ching-Lin Fan; Yu-Sheng Lin; Yan-Wei Liu

2010-01-01

360

Millisecond time scale atmospheric light pulses associated with solar and magnetospheric activity.  

NASA Technical Reports Server (NTRS)

By using a wide-angle photomultiplier system a class of millisecond time scale diffuse atmospheric light emission of terrestrial origin has been discovered. These fast atmospheric pulsation events also show damped oscillations around 10-kHz frequency, which distinguishes them from ordinary lightning-type events. Evidence is presented for the enhancement in the rate of these events induced by solar flare activity.

Ogelman, H.

1973-01-01

361

Electroluminescence properties of rare-earth-activated SrS thin films under light irradiation  

Microsoft Academic Search

We have investigated the effects of external light irradiation on the electroluminescence properties of SrS thin films activated with Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Tm in order to clarify the generation mechanism of the dynamic space charge. The photo-induced space charge is observed in all of our fabricated devices, and that of SrS:Ce is the

Isao Tanaka; Yoshitaka Izumi; Katsu Tanaka; Yoji Inoue; Shinji Okamoto

2000-01-01

362

Anticonvulsant and anesthetic effects of a fluorescent neurosteroid analog activated by visible light  

Microsoft Academic Search

Most photoactivatable compounds suffer from the limitations of the ultraviolet wavelengths that are required for activation. We synthesized a neuroactive steroid analog with a fluorescent (7-nitro-2,1,3-benzoxadiazol-4-yl) amino (NBD) group in the ? configuration at the C2 position of (3?,5?)-3-hydroxypregnan-20-one (allopregnanolone, 3?5?P). Light wavelengths (480 nm) that excite compound fluorescence strongly potentiate GABAA receptor function. Potentiation is limited by photodepletion of

Lawrence N Eisenman; Hong-Jin Shu; Gustav Akk; Cunde Wang; Brad D Manion; Geraldine J Kress; Alex S Evers; Joe Henry Steinbach; Douglas F Covey; Charles F Zorumski; Steven Mennerick

2007-01-01

363

Octahedral-shaped perovskite nanocrystals and their visible-light photocatalytic activity.  

PubMed

Octahedral-shaped perovskite PbTiO3 nanocrystals (PT OCT) with well-defined {111} facets exposed have been successfully synthesized via a facile hydrothermal method by using LiNO3 as an ion surfactant. The Li-O bond on the surface of PT OCT nanocrystals is essential to the stability of such nanocrystals and also results in a dramatic high visible-light photocatalytic activity. PMID:24769605

Yin, Simin; Tian, He; Ren, Zhaohui; Wei, Xiao; Chao, Chunying; Pei, Jingyuan; Li, Xiang; Xu, Gang; Shen, Ge; Han, Gaorong

2014-06-01

364

The antimicrobial properties of light-activated polymers containing methylene blue and gold nanoparticles  

Microsoft Academic Search

We report the formation of polysiloxane polymers containing embedded methylene blue and gold nanoparticles incorporated by a swell-encapsulation-shrink method. These polymers show significant antimicrobial activity against methicillin-resistant Staphylococcus aureus and Escherichia coli with up to a 3.5 log10 reduction in the viable count when exposed for 5min to light from a low power 660nm laser. The bacterial kill is due

Stefano Perni; Clara Piccirillo; Jonathan Pratten; Polina Prokopovich; Wojciech Chrzanowski; Ivan P. Parkin; Michael Wilson

2009-01-01

365

STS-39 MS Hieb floats in single person life raft in JSC's WETF Bldg 29 pool  

NASA Technical Reports Server (NTRS)

STS-39 Mission Specialist (MS) Richard J. Hieb, wearing launch and entry suit (LES) and launch and entry helmet (LEH), floats in single person life raft after landing in JSC's Weightless Environment Training Facility (WETF) Bldg 29 pool. During emergency egress bailout procedures, Hieb practiced procedures necessary for a water landing. Divers monitor Hieb's activity.

1990-01-01

366

Design of crossed-mirror array to form floating 3D LED signs  

NASA Astrophysics Data System (ADS)

3D representation of digital signage improves its significance and rapid notification of important points. Our goal is to realize floating 3D LED signs. The problem is there is no sufficient device to form floating 3D images from LEDs. LED lamp size is around 1 cm including wiring and substrates. Such large pitch increases display size and sometimes spoils image quality. The purpose of this paper is to develop optical device to meet the three requirements and to demonstrate floating 3D arrays of LEDs. We analytically investigate image formation by a crossed mirror structure with aerial aperture, called CMA (crossed-mirror array). CMA contains dihedral corner reflectors at each aperture. After double reflection, light rays emitted from an LED will converge into the corresponding image point. We have fabricated CMA for 3D array of LEDs. One CMA unit contains 20 x 20 apertures that are located diagonally. Floating image of LEDs was formed in wide range of incident angle. The image size of focused beam agreed to the apparent aperture size. When LEDs were located three-dimensionally (LEDs in three depths), the focused distances were the same as the distance between the real LED and the CMA.

Yamamoto, Hirotsugu; Bando, Hiroki; Kujime, Ryousuke; Suyama, Shiro

2012-02-01

367

Airborne electromagnetic bathymetry investigations in Port Lincoln, South Australia - comparison with an equivalent floating transient electromagnetic system  

Microsoft Academic Search

Helicopter time-domain airborne electromagnetic (AEM) methodology is being investigated as a reconnaissance technique for bathymetric mapping in shallow coastal waters, especially in areas affected by water turbidity where light detection and ranging (LIDAR) and hyperspectral techniques may be limited. Previous studies in Port Lincoln, South Australia, used a floating AEM time-domain system to provide an upper limit to the expected

Julian Vrbancich

2011-01-01

368

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

369

Interactions between sediment propagule banks and sediment nutrient fluxes explain floating plant dominance in stagnant shallow waters  

Microsoft Academic Search

Mats of floating plants are known to have detrimental effects on aquatic life as they reduce the penetration of light so that submerged species are unable to develop. These mats also prevent gaseous exchange between water and atmosphere resulting in anoxic conditions of the water layer. In shallow waters, nutrient fluxes from the sedi- ment to the water layer are

Ger Boedeltje; Alfons J. P. Smolders; Leon P. M. Lamers; Jan G. M. Roelofs

2005-01-01

370

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

371

Photocatalytic activity of titanium dioxide modified with thiourea under the action of visible light  

NASA Astrophysics Data System (ADS)

Photocatalyst powders were synthesized from nanosized titanium dioxide crystals modified by sintering with thiourea (TU). The powders contained anatase crystals of various sizes. TU-TiO2 powders absorbed visible light to produce an oxidizer (oxidizing iodide) and a reducing agent (reducing tetranitromethane). The activity of TU-TiO2 correlated with the size of nanocrystals. The photocatalytic activity of TU-TiO2 was suggested to be related to impurity states appearing during modification in the forbidden band of TiO2.

Chubukov, P. A.; Denisov, N. N.; Gorenberg, A. A.; Shilov, G. V.; Kozlov, Yu. N.; Groznov, I. N.; Nadtochenko, V. A.

2008-09-01

372

Visible-light photocatalytic activity and deactivation mechanism of Ag3PO4 spherical particles.  

PubMed

Ag(3)PO(4) spherical particles were synthesized by a facile precipitation method using silver nitrate and Na(2) HPO(4) as precursors. The as-prepared samples had a high photocatalytic activity toward Rhodamine B (RhB) degradation under visible-light illumination. With increasing recycling times the photocatalytic activity first increased and then decreased. Based on systematic characterization of particles by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis absorption spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), a possible mechanism responsible for the improvement and subsequent decline of the photocatalytic performance of Ag(3)PO(4) is proposed. Ag(3)PO(4) spherical particles recycled for four times showed the highest photocatalytic activity because, according to our mechanism, Ag nanoparticles deposited on Ag(3)PO(4) acted as electron trapping centers to prevent photogenerated electron-hole pairs from recombination. A further increase in the recycle times decreases the photocatalytic activity owing to the shielding effect by Ag layers on the surface of Ag(3)PO(4). The results presented herein shed new light on the photostability of Ag(3) PO(4) spherical particles and are potentially applicable to other photocatalytically active composites. PMID:22678948

Wang, Wenguang; Cheng, Bei; Yu, Jiaguo; Liu, Gang; Fan, Wenhong

2012-08-01

373

Microwave hydrothermal synthesis of AgInS{sub 2} with visible light photocatalytic activity  

SciTech Connect

Highlights: {yields} AgInS{sub 2} nanoparticles were synthesized by a microwave hydrothermal method. {yields} This method involves no organic solvents, catalysts, or surfactants. {yields} AgInS{sub 2} showed higher activity for photocatalytic degradation MO than TiO{sub 2-x}N{sub x}. {yields} Holes, O{sub 2}{center_dot}{sup -}, and H{sub 2}O{sub 2} played an important role in the photocatalytic process. -- Abstract: AgInS{sub 2} nanoparticles with superior visible light photocatalytic activity were successfully synthesized by a microwave hydrothermal method. This method is a highly efficient and rapid route that involves no organic solvents, catalysts, or surfactants. The photocatalytic activity of AgInS{sub 2} nanoparticles was investigated through the degradation of dyes under visible light irradiation. Compared with TiO{sub 2-x}N{sub x}, AgInS{sub 2} has exhibited a superior activity for photocatalytic degradation MO under the same condition. The experiment results showed that superoxide radicals (O{sub 2}{center_dot}{sup -}), hydrogen peroxides (H{sub 2}O{sub 2}) and holes (h{sup +}) were the mainly active species for the degradation of organic pollutants over AgInS{sub 2}. Through the determination of flat band potential, the energy band structure of the sample was obtained. A possible mechanism for the degradation of organic pollutant over AgInS{sub 2} was proposed.

Zhang, Wenjuan [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)] [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China); Li, Danzhen, E-mail: dzli@fzu.edu.cn [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)] [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China); Chen, Zhixin; Sun, Meng; Li, Wenjuan; Lin, Qiang; Fu, Xianzhi [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)] [Research Institute of Photocatalysis, State Key Laboratory Breeding Base of Photocatalysis, Fuzhou University, Gongye Road No. 523, Fuzhou 350002, Fujian (China)

2011-07-15

374

Pigmented Free-floating Vitreous Cyst.  

PubMed

A 45-year-old man presented with a mobile shadow in the central visual field of his left eye for the preceding 4 months. His visual acuity was not affected. Funduscopy showed a brownish, oval-shaped structure floating in the vitreous cavity of the left eye. B-scan ultrasound demonstrated an oval-spherical hypoechogenic structure floating at the posterior pole. The absence of pertinent medical history and normal results from systemic exploration suggested a congenital etiology. The condition was observed regularly without any evidence of change. Differential diagnosis of vitreous cysts is important in order to establish an adequate therapeutic approach. [Ophthalmic Surg Lasers Imaging Retina. 2014;45:e23-e25.]. PMID:24845723

Caminal-Mitjana, José María; Padrón-Pérez, Noel; Arias-Barquet, Lluís; Caso, Marcos Javier Rubio

2014-01-01

375

Electrodynamic convection in silicon floating zones  

NASA Astrophysics Data System (ADS)

Using a simplified Navier-Stokes equation it has been possible to compute the electrodynamic convection generated by a radio frequency coil field for the modern needle-eye float-zone growth of silicon. The calculated electrodynamic force in such a zone shows maximum values up to 11.7 N/cm 3 and generates flow velocities between 25 and 100 cm/s. As only superficial convection can be brought about by electrodynamic forces, the axial and radial dopant incorporation will not be influenced strongly. A comparison of electrodynamic forces with the other forces possibly causing flow in silicon floating zones shows that the electrodynamic forces exceed all other forces by several orders of magnitude.

Mühlbauer, A.; Erdmann, W.; Keller, W.

1983-12-01

376

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

377

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.

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

2011-01-01

378

Imaging of optically active biological structures by use of circularly polarized light  

SciTech Connect

If an optically active sample is placed in a microscope and illuminated with circularly polarized light, an image can be formed that is related to the circular dichroism of each feature of the sample. A theoretical investigation has been done for the circular differential image obtained by subtracting the images formed under right- and left-circularly polarized light. Two types of differential images are possible: (i) dark-field images formed from light reflected or scattered by the sample and (ii) bright-field images formed from light transmitted through the sample. The sign and magnitude of each feature in a circular differential image strongly depend on the structure of the sample. The dark-field circular differential images are most sensitive to large features with dimensions similar to the wavelength of illumination whereas the bright-field images are most sensitive to the short-range molecular order. Applications of circular differential imaging may include clinical fingerprinting of normal and transformed cells and structural analysis of individual cellular components.

Keller, D.; Bustamante, C.; Maestre, M.F.; Tinoco, I. Jr.

1985-01-01

379

Floating ice platforms: offshore oil exploration  

Microsoft Academic Search

Exploratory drilling offshore in the Canadian Arctic Islands in water depths of 200-1300 ft from floating platforms of thickened ice has proven very successful, reports Fenco Consultants Ltd. Designs based on elastic-plate theory have produced strong platforms that behaved much as predicted. In designing the platforms, Fenco used reduced-modulus concepts to estimate creep effects and long-term deflections, making possible the

D. M. Masterson; H. R. Kivisild

1980-01-01

380

The health impact of floating support  

Microsoft Academic Search

Under the Supporting People Programme, low-level ‘floating’ support is available to help vulnerable people live independently in their own accommodation. There is a good deal of research to indicate that this sort of support, particularly in social housing, is effective in helping people to sustain their tenancies, and that their well-being and self-esteem are improved as a result. However, there

Terry Allen

2006-01-01

381

An Autozeroing Floating-Gate Amplifier  

Microsoft Academic Search

We have developed a bandpass floating-gate amplifier that uses tunneling and pFET hot-electron injection to set its dc operating point adaptively. Because the hot-electron injection is an inherent part of the pFET's behavior, we obtain this adaptation with no additional circuitry. Because the gate currents are small, the circuit exhibits a high-pass characteristic with a cutoff frequency less than 1

Paul Hasler; Bradley A. Minch; Chris Diorio

2001-01-01

382

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

383

Floating Ice: Grades K-1: Illustrated 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 version is a full-color PDF that can be printed, cut and folded to form a book. Each book contains color photographs and illustrations.

Fries-Gaither, Jessica

384

Light Painting  

NSDL National Science Digital Library

In this activity, learners create art by "light painting," also known as light drawing or light graffiti. Learners use a photographic technique that manipulates the shutter speed on your camera to allow more light to be captured in your photograph. The exposures are usually made at night or in a darkened room by moving a hand-held light source or by moving the camera. Activity has a list of artists and websites to explore for inspiration.

Houston, Children'S M.

2010-01-01

385

Pigmented Free-Floating Posterior Vitreous Cyst  

PubMed Central

Vitreous cysts are very rare ocular malformations. In this observational case study, we report on an unusual case of a pigmented free-floating vitreous cyst and discuss its differential diagnosis. A 14-year-old male was referred to ophthalmology for a pigmented lesion in his left eye. He complained of an intermittent floater in the left eye. Visual acuity was 20/20 in the right eye and 20/40 in the left eye. Fundus examination was unremarkable bilaterally, except for a piece of brownish oval material floating in the vitreous in the left eye. He had received a knock on the left side of his head a few days before the visual discomfort of the left eye. Real-time ultrasound of the left eye detected a piece of hyperechogenic spherical material with no internal reflectivity, floating in the middle of the vitreous. The first use of color Doppler ultrasound in this context indicated no arterial flow, ruling out the presence of a persistent hyaloid artery. Intraocular cysts are rare ocular disorders, which have been divided into clear and pigmented cysts, and into those that occupy the anterior chamber, the retrolental space, and the vitreous cavity. This last is extremely rare. We describe such a case.

Brue, Claudia; Mariotti, Cesare; De Franco, Edoardo; De Franco, Nicola; Giovannini, Alfonso

2012-01-01

386

Drill vessels float in aerated water  

SciTech Connect

Model tests, calculations, and case studies prove that a floating vessel will not sink due to gas reducing the water density in or adjacent to a subsea blowout. Several floating drill vessels have been lost as a result of subsea blowouts. Reports have circulated that the rig sank into something similar to a hole in the ocean caused by gas bubbles suspended in the water reducing its specific gravity. These erroneous reports, believed as truth by many people, have resulted in the modification of operations resulting in decreased safety. Several subsea well control operations have caused accidents and losses because the riser was not disconnected. This action was taken in fear of sinking in aerated water. The losses occurred because the vessel winched itself off the drill site to get away from the subsea well before disconnecting. Due to the high riser/BOP angle, the riser could not be disconnected and well control was later lost and the gas/oil flowed directly to the rig floor where massive fire/explosion damage occurred. If there had been a better understanding of water density, the rig personnel could have closed all hatches, shut-down all engines, disconnected the riser and released mooring lines at one end of the rig, and safely removed the rig out of the aerated water. This paper presents some of the technical data and references available which prove that a floating vessel will not sink due to loss of water density.

Hammett, D.S.

1985-01-01

387

Multiview autosterescopic display with floating real image  

NASA Astrophysics Data System (ADS)

This paper proposes multiview version of autostereoscopic display FLOATS (Fresnel Lens based Optical Apparatus for Touchable-distance Stereoscopy), which combines generation of floating real image and parallax presentation to show realistic 3-D image within the viewer's reach. Earlier versions of FLOATS have required a head tracker, physical motion control of filters or mirrors, and transformation of image in accordance with the viewer's motion to keep on presenting different images to each eye. To do away with these requirements, we propose two methods which realize multiview presentation to the viewer. One method is to use multiple LCD panels and multiple fixed mirrors instead of mobile mirrors. The other method is to use mutiple projectors, fly-eye lenses, and fresnel lenses. Though the former system doesn't cost much, it is not practical to present more than 10 views. In the latter system it is practical to present more than 30 views, which can realize presentation of both horizontal and vertical parallax. With this technology the viewers can perceive undistorted 3-D space from any angle, which makes it possible for multiple viewers to observe 3-D image at consistent position from different angles at the same time.

Kakeya, Hideki; Kobe, Naoto; Kasano, Hidehiro

2004-05-01

388

Pigmented free-floating posterior vitreous cyst.  

PubMed

Vitreous cysts are very rare ocular malformations. In this observational case study, we report on an unusual case of a pigmented free-floating vitreous cyst and discuss its differential diagnosis. A 14-year-old male was referred to ophthalmology for a pigmented lesion in his left eye. He complained of an intermittent floater in the left eye. Visual acuity was 20/20 in the right eye and 20/40 in the left eye. Fundus examination was unremarkable bilaterally, except for a piece of brownish oval material floating in the vitreous in the left eye. He had received a knock on the left side of his head a few days before the visual discomfort of the left eye. Real-time ultrasound of the left eye detected a piece of hyperechogenic spherical material with no internal reflectivity, floating in the middle of the vitreous. The first use of color Doppler ultrasound in this context indicated no arterial flow, ruling out the presence of a persistent hyaloid artery. Intraocular cysts are rare ocular disorders, which have been divided into clear and pigmented cysts, and into those that occupy the anterior chamber, the retrolental space, and the vitreous cavity. This last is extremely rare. We describe such a case. PMID:23119209

Bruè, Claudia; Mariotti, Cesare; De Franco, Edoardo; De Franco, Nicola; Giovannini, Alfonso

2012-01-01

389

FPP [Floating Potential Probe] Results, Final Report  

NASA Technical Reports Server (NTRS)

The Floating Potential Probe (FPP) operated on the International Space Station (ISS) from December 2000 to April 2001. During that time, it took many measurements of the ISS floating potential and the electron density and temperature. Those measurements were used as inputs to the Environments WorkBench (EWB) model of ISS potentials (originally developed by SAIC, but now sometimes called the Boeing model) that is used even today to predict charging levels for ISS. FPP is now completely defunct, having been removed and ejected from ISS. With the advent of the new Floating Potential Monitoring Unit (FPMU) on ISS, and the beginning of ISS operations with two large solar array panels instead of just one, a review of FPP measurements can offer comparisons with the new FPMU data and perhaps improve the accuracy of future ISS charging predictions. In particular, FPP measurements during times of low electron temperature and high electron density (the times of worst ISS charging) will be brought forward for comparison with the newly obtained FPMU data.

Ferguson, Dale C.

2007-01-01

390

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

391

Socially adjusted synchrony in the activity profiles of common marmosets in light-dark conditions.  

PubMed

Synchronized state of activity and rest might be attained by mechanisms of entrainment and masking. Most zeitgebers not only act to entrain but also to mask circadian rhythms. Although the light-dark (LD) cycle is the main zeitgeber of circadian rhythms in marmosets, social cues can act as weaker zeitgebers. Evidence on the effects of social entrainment in marmosets has been collected in isolated animals or in pairs where activity is not individually recorded. To characterize the synchronization between the daily activity profiles of individuals in groups under LD conditions, the motor activity of animals from five groups was continuously monitored using actiwatches for 15 days during the 5th, 8th, and 11th months of life of juveniles. Families consisting of twins (4 ??/1 ??) and their parents were maintained under controlled lighting (LD 12:12?h), temperature, and humidity conditions. Synchronization was evaluated through the synchrony between the circadian activity profiles obtained from the Pearson correlation index between possible pairs of activity profiles in the light and dark phases. We also calculated the phase-angle differences between the activity onset of one animal in relation to the activity onset of each animal in the group (?(on)). A similar procedure was performed for activity offset (?(off)). By visual analysis, the correlation between the activity profiles of individuals within each family was stronger than that of individuals from different families. A mixed-model analysis showed that within the group, the correlation was stronger between twins than between twins and their parents in all families, except for the family in which both juveniles were males. Because a twin is an important social partner for juveniles, a sibling is likely to have a stronger influence on its twin's activity rhythm than other family members. Considering only the light phase, the second strongest correlation was observed between the activity profiles of the individuals in the reproductive pair. Regarding the parameters ?(on) and ?(off), the juvenile/juvenile dyad had lower values than the other dyads, but these differences did not reach statistical significance in relation to all dyads. Comparing the results of the ?(on) and ?(off), and correlation indices, we suggest that the latter could detect differences between the animals that were not observed in the results of the phase-angle differences. These differences could be related to changes that occur during the active phase but not only in a particular phase, such as the temporal changes during the activity phase that characterize unimodal or bimodal patterns. Based on the differences in the correlations between individuals subjected to the same LD routine, we suggest that social cues modulate the circadian activity profiles of marmosets as a result of interactions between the animals within each group. Future studies are necessary to characterize the mechanisms of synchronization that are involved in this social modulation. PMID:23767997

Melo, Paula; Gonçalves, Bruno; Menezes, Alexandre; Azevedo, Carolina

2013-07-01

392

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

393

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

394

Dextran causes aggregation of mitochondria and influences their oxidoreductase activities and light scattering.  

PubMed

It has been reported that dextrans diminish the intermembrane space of mitochondria, increase the number of contact sites between the inner and the outer mitochondrial membranes, decrease the outer membrane permeability to adenosine 5(')-diphosphate, and change the kinetic properties of mitochondrial kinases. In the present work the influence of dextran M40 (5% w/v) on the oxidoreductase activities of the inner and outer membranes of mitochondria, the interaction of cytochrome c with mitochondrial membranes, and the light scattering by rat liver mitochondria were studied. No influence of dextran on the release of cytochrome c from mitochondria or its interaction with mitochondrial membranes was observed. Decreases in the NADH-oxidase (to 80+/-2% of the control), NADH-cytochrome c reductase (to 26+/-2%), succinate-cytochrome c reductase (to 70+/-5%), and NADH-ferricyanide reductase (to 75+/-3%) activities induced by dextran, which may be due to the mitochondrial aggregation, were observed. The formation of aggregates was registered by light scattering, confirmed by light microscopy, and explained within the framework of the Gouy-Chapman theory of the electrical double layer. The observed mitochondrial aggregation seems to be useful also for understanding the mechanisms of mitochondrial condensation and perinuclear clustering during apoptosis. PMID:12667481

Lemeshko, Victor V; Solano, Sigifredo; López, Luis F; Rendón, Dairo A; Ghafourifar, Pedram; Gómez, Luis A

2003-04-15

395

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

396

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

397

A novel orange phosphor of Eu 2+-activated calcium chlorosilicate for white light-emitting diodes  

NASA Astrophysics Data System (ADS)

Novel orange phosphor of Eu 2+-activated calcium chlorosilicate was synthesized at 1273 K by conventional solid-state reactions under reductive atmosphere and investigated by means of photoluminescence excitation, diffuse reflectance and emission spectroscopies. These results show that this phosphor can be efficiently excited by the incident light of 300-450 nm, well matched with the emission band of 395 nm-emitting InGaN chip, and emits an intense orange light peaking at 585 nm. By combining this phosphor with a 395 nm-emitting InGaN chip, an intense orange light-emitting diode (LED) was fabricated. Under 20 mA forward-bias current, its CIE chromaticity coordinates are (0.486, 0.446). The dependence of as-fabricated orange LED on forward-bias current indicates that it shows excellent chromaticity stability and luminance saturation. These results show that this Eu 2+-activated calcium chlorosilicate is a promising orange-emitting phosphor for near-ultraviolet (UV) InGaN-based white LED.

Ding, Weijia; Wang, Jing; Zhang, Mei; Zhang, Qiuhong; Su, Qiang

2006-11-01

398

Epidemiology of unintentional injuries among children under six years old in floating and residential population in four communities in beijing: a comparative study.  

PubMed

To explore and compare the epidemiological characteristics of non-fatal unintentional injury among children in floating and residential population. Using a structured survey, quantitative data were collected on a total of 352 floating and 201 residential families. Some potential influencing factors were questioned, such as socio-demographic characteristics, injury-related family environment, knowledge, attitude and behavior, and child's character. The self-reported incidence of non-fatal unintentional injuries was 11.9 % in the floating group and 12.9 % in the residential group. Unintentional injuries were more serious and caused more disease burden in floating children than residential children, with the average medical cost being over ten times in the floating group than in the residential group. Results of multiple regression analysis showed that children living in floating families have more risk of unintentional injuries than those children in residential families. Older children and children with extroverted character were more vulnerable to unintentional injuries. Risky family environment was also an important risk factor of unintentional injuries. Better household economic status and having more siblings appeared to reduce the probability of unintentional injuries among children. Floating children are more vulnerable to unintentional injuries comparing with residential children. These findings can be used as preliminary data supporting intervention strategies and activities to promote safe living environment and decrease injury incidence among floating children. PMID:23793489

Xu, Tao; Gong, Limin; Wang, Huishan; Zhang, Rui; Wang, Xiaoying; Kaime-Atterhög, Wanjiku

2014-05-01

399

Double-doped TiO2 nanoparticles as an efficient visible-light-active photocatalyst and antibacterial agent under solar simulated light  

NASA Astrophysics Data System (ADS)

Silver and nitrogen doped TiO2 nanoparticles (NPs) were synthesized via sol–gel method. The physicochemical properties of the achieved NPs were characterized by various methods including X-Ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultra violet–visible absorption spectroscopy (UV–vis). Both visible-light photocatalytic activity and antimicrobial properties were successfully demonstrated for the degradation of Rhodamine B (Rh. B.), as a model dye, and inactivation of Escherichia coli (E. coli), as a representative of microorganisms. The concentration of the employed dopant was optimized and the results revealed that the silver and nitrogen doped TiO2 NPs extended the light absorption spectrum toward the visible region and significantly enhanced the photodegradation of model dye and inactivation of bacteria under visible-light irradiation while double-doped TiO2 NPs exhibited highest photocatalytic and antibacterial activity compared with single doping. The significant enhancement in the photocatalytic activity and antibacterial properties of the double doped TiO2 NPs, under visible-light irradiation, can be attributed to the generation of two different electronic states acting as electron traps in TiO2 and responsible for narrowing the band gap of TiO2 and shifting its optical response from UV to the visible-light region.

Ashkarran, Ali Akbar; Hamidinezhad, Habib; Haddadi, Hedayat; Mahmoudi, Morteza

2014-05-01

400

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

401

Synthesis of Cross Bi2 WO6 Microwafers with Enhanced Photocatalytic Activity Under Visible Light Irradiation  

NASA Astrophysics Data System (ADS)

Novel cross Bi2 WO6 microwafers have been fabricated by a facile acetone-assisted solvothermal method in high quantity. The structure characterizations of the microwafers were investigated in detail by means of X-ray powder diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. The results indicate that the orthorhombic phase of Bi2 WO6 with high crystallinity can be obtained and each microwafer is polycrystalline in nature and organized by the nanoflake subunits. UV-visible diffuse reflectance spectrum of the prepared Bi2 WO6 microwafers demonstrates that they have absorption in the visible light region. The photocatalytic activity of cross Bi2 WO6 microwafers toward (Rhodamine B) RhB degradation under visible light was investigated, and it was found to be significantly better than that of Bi2 WO6 sample prepared by solid-state reaction (SSR-Bi2 WO6).

Wang, Guizhen; Wan, Gengping; Lin, Shiwei

2012-02-01

402

Preparation of hollow porous Cu2O microspheres and photocatalytic activity under visible light irradiation  

PubMed Central

Cu2O p-type semiconductor hollow porous microspheres have been prepared by using a simple soft-template method at room temperature. The morphology of as-synthesized samples is hollow spherical structures with the diameter ranging from 200 to 500?nm, and the surfaces of the spheres are rough, porous and with lots of channels and folds. The photocatalytic activity of degradation of methyl orange (MO) under visible light irradiation was investigated by UV-visible spectroscopy. The results show that the hollow porous Cu2O particles were uniform in diameters and have an excellent ability in visible light-induced degradation of MO. Meanwhile, the growth mechanism of the prepared Cu2O was also analyzed. We find that sodium dodecyl sulfate acted the role of soft templates in the synthesis process. The hollow porous structure was not only sensitive to the soft template but also to the amount of reagents.

2012-01-01

403

Neural control of motile activity of light-sensitive iridophores in the neon tetra.  

PubMed

Experiments with skin pieces revealed that the sympathetic nervous system controls the activity of the light-sensitive iridophores in the stripes of the neon tetra. The spectral peak reflected from the cells was shifted toward longer wavelengths as a result of a direct interaction between norepinephrine and alpha-adrenoceptors present on the cell membrane. Adenosine accelerated the recovery from the effects of the amine. Such regulation seems to operate when fish are in an excited state or under stress. Since alpha-melanophore-stimulating hormone (alpha-MSH), melanin-concentrating hormone (MCH) and melatonin caused the responses only at high concentrations, it is possible that these peptides and amine do not affect the properties of the light-reflecting cells in vivo. PMID:2557604

Nagaishi, H; Oshima, N

1989-01-01

404

X-ray light curves of active galactic nuclei are phase incoherent  

NASA Technical Reports Server (NTRS)

We compute the Fourier phase spectra for the light curves of five low-luminosity active galactic nuclei observed by EXOSAT. There is no statistically significant phase coherence in any of them. This statement is equivalent, subject to a technical caveat, to a demonstration that their fluctuation statistics are Gaussian. Models in which the X-ray output is controlled wholly by a unitary process undergoing a nonlinear limit cycle are therefore ruled out, while models with either a large number of randomly excited independent oscillation modes or nonlinearly interacting spatially dependent oscillations are favored. We also demonstrate how the degree of phase coherence in light curve fluctuations influences the application of causality bounds on internal length scales.

Krolik, Julian; Done, Chris; Madejski, Grzegorz

1993-01-01

405

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

406

Floating Oil-Spill Containment Device  

NASA Technical Reports Server (NTRS)

Previous oil containment booms have an open top that allows natural gas to escape, and have significant oil leakage due to wave action. Also, a subsea pyramid oil trap exists, but cannot move relative to moving oil plumes from deepsea oil leaks. The solution is to have large, moveable oil traps. One version floats on the sea surface and has a flexible tarp cover and a lower weighted skirt to completely entrap the floating oil and natural gas. The device must have at least three sides with boats pulling at each apex, and sonar or other system to track the slowly moving oil plume, so that the boats can properly locate the booms. The oil trap device must also have a means for removal of the oil and the natural gas. A second design version has a flexible pyramid cover that is attached by lines to ballast on the ocean floor. This is similar to fixed, metal pyramid oil capture devices in the Santa Barbara Channel off the coast of California. The ballast lines for the improved design, however, would have winches that can move the pyramid to always be located above the oil and gas plume. A third design is a combination of the first two. It uses a submerged pyramid to trap oil, but has no anchor and uses boats to locate the trap. It has ballast weights located along the bottom of the tarp and/or at the corners of the trap. The improved floating oil-spill containment device has a large floating boom and weighted skirt surrounding the oil and gas entrapment area. The device is triangular (or more than three sides) and has a flexible tarp cover with a raised gas vent area. Boats pull on the apex of the triangles to maintain tension and to allow the device to move to optimum locations to trap oil and gas. The gas is retrieved from a higher buoyant part of the tarp, and oil is retrieved from the floating oil layer contained in the device. These devices can be operated in relatively severe weather, since waves will break over the devices without causing oil leaking. Also, natural gas is entrapped and can be retrieved. All designs can use sonar to locate the moving oil plume, and then be relocated by using boats or winches to move the oil trapping devices. These devices can be constructed of treated, non-permeable DuPont Kevlar cloth (or similar material).

Jones, Jack A.

2012-01-01

407

Float processing of high-temperature complex silicate glasses and float baths used for same  

NASA Technical Reports Server (NTRS)

A float glass process for production of high melting temperature glasses utilizes a binary metal alloy bath having the combined properties of a low melting point, low reactivity with oxygen, low vapor pressure, and minimal reactivity with the silicate glasses being formed. The metal alloy of the float medium is exothermic with a solvent metal that does not readily form an oxide. The vapor pressure of both components in the alloy is low enough to prevent deleterious vapor deposition, and there is minimal chemical and interdiffusive interaction of either component with silicate glasses under the float processing conditions. Alloys having the desired combination of properties include compositions in which gold, silver or copper is the solvent metal and silicon, germanium or tin is the solute, preferably in eutectic or near-eutectic compositions.

Cooper, Reid Franklin (Inventor); Cook, Glen Bennett (Inventor)

2000-01-01

408

Traffic Sign Recognition with Invariance to Lighting in Dual-Focal Active Camera System  

NASA Astrophysics Data System (ADS)

In this paper, we present an automatic vision-based traffic sign recognition system, which can detect and classify traffic signs at long distance under different lighting conditions. To realize this purpose, the traffic sign recognition is developed in an originally proposed dual-focal active camera system. In this system, a telephoto camera is equipped as an assistant of a wide angle camera. The telephoto camera can capture a high accuracy image for an object of interest in the view field of the wide angle camera. The image from the telephoto camera provides enough information for recognition when the accuracy of traffic sign is low from the wide angle camera. In the proposed system, the traffic sign detection and classification are processed separately for different images from the wide angle camera and telephoto camera. Besides, in order to detect traffic sign from complex background in different lighting conditions, we propose a type of color transformation which is invariant to light changing. This color transformation is conducted to highlight the pattern of traffic signs by reducing the complexity of background. Based on the color transformation, a multi-resolution detector with cascade mode is trained and used to locate traffic signs at low resolution in the image from the wide angle camera. After detection, the system actively captures a high accuracy image of each detected traffic sign by controlling the direction and exposure time of the telephoto camera based on the information from the wide angle camera. Moreover, in classification, a hierarchical classifier is constructed and used to recognize the detected traffic signs in the high accuracy image from the telephoto camera. Finally, based on the proposed system, a set of experiments in the domain of traffic sign recognition is presented. The experimental results demonstrate that the proposed system can effectively recognize traffic signs at low resolution in different lighting conditions.

Gu, Yanlei; Panahpour Tehrani, Mehrdad; Yendo, Tomohiro; Fujii, Toshiaki; Tanimoto, Masayuki

409

Visible-light activated titania perovskite photocatalysts: Characterisation and initial activity studies  

Microsoft Academic Search

The effect of partial substitution of the titanium cation on the optophysical properties and photocatalytic oxidation activity of sol–gel synthesised CeCoxTi1?xO3+? perovskite system has been examined. BET surface areas of the perovskite specimens were generally higher (80–130m2g?1) than standard Degussa P25 (50m2g?1) titania. Although the presence of Ce improved BET area, increased Co content and high calcination temperature was detrimental

Daphne Qiong Fei; Tedi Hudaya; Adesoji A. Adesina

2005-01-01

410

Characterization of poly(vinyl acetate) based floating matrix tablets.  

PubMed

Floating Kollidon SR matrix tablets containing Propranolol HCl were developed and characterized with respect to drug release characteristics and floating strength. Kollidon SR was able to delay Propranolol HCl release efficiently. Drug release kinetics was evaluated using the Korsmeyer-Peppas model and found to be governed by Fickian diffusion. Tablet floating started immediately and continued for 24 h. It was possible to monitor the floating strength of the matrix devices using a simple experimental setup. Floating strength was related to Kollidon SR level with improved floating characteristics for samples with a high polymer/drug ratio. Swelling characteristics of the tablets were analyzed by applying the equation according to Therien-Aubin et al. The influence of the polymer content on swelling characteristics was found to be only marginal. Furthermore, the new method of benchtop MRI was introduced to study the water diffusion and swelling behaviour non-invasively and continuously. PMID:18180069

Strübing, Sandra; Metz, Hendrik; Mäder, Karsten

2008-03-01

411

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

412

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.

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

2013-01-01

413

Float charging of valve-regulated lead-acid batteries: A balancing act between secondary reactions  

SciTech Connect

The behavior of valve-regulated lead-acid batteries on float charging is influenced by many interacting parameters. A mathematical model has been developed that describes the effects of kinetic cell parameters, float voltage (or current), and temperature on electrode potentials and rates of electrode reactions. The considered reactions are: hydrogen evolution, oxygen evolution, oxygen reduction, grid corrosion, and discharge of active material that may occur under unfavorable conditions. This model, combined with selected experiments, is a very effective tool for surveying the complex situation during float charging. It can also be applied to vented batteries. With model simulations, some fundamental relationships have been shown: when the oxygen reduction efficiency is near 100%, the kinetics of hydrogen evolution and grid corrosion govern electrode polarization at specified float conditions. To achieve a long service life, the rates of water loss and grid dis-integration have to be small, and simultaneously a satisfactory state of charge of the battery is required. Hence, the optimum design of a valve-regulated battery requires a high and balanced hindrance of hydrogen evolution and grid corrosion. Furthermore, small rates of oxygen evolution are favorable. Oxygen intake from the surroundings by a leakage may cause discharge of the negative electrodes. The model helps to estimate the maximum size of such a leakage that can be tolerated. Temperature has not only a marked effect on all the reaction rates, but also influences electrode polarization and the delicate balance of currents, because the activation energies of the various processes differ.

Berndt, D.; Teutsch, U. [VARTA Batterie AG, Kelkheim (Germany)

1996-03-01

414

A real time video data adjusting method for active matrix organic light emitting diode displays with high image quality  

Microsoft Academic Search

A real time video data adjusting method for television applications of active matrix organic light emitting diode (AMOLED) displays with high image quality is proposed. The proposed method senses electrical characteristics of polycrystalline silicon (poly-Si) thin film transistors (TFTs) and organic light emitting diode (OLED) of pixels and compensates nonuniform luminance due to the electrical characteristic variations of TFTs and

Ung-Gyu Min; Hai-Jung In; Oh-Kyong Kwon

2009-01-01

415

Experience the magic of light and color: outreach activity by Universidad del Valle student chapter  

NASA Astrophysics Data System (ADS)

During 2007, the Universidad del Valle Student Chapter presented a proposal for developing an educational outreach activity for children from an underprivileged zone to the Optical Society of America Foundation (OSAF) and to SPIE. The activity was carried out jointly by OSA and SPIE Universidad del Valle Student Chapters in the hillsides of Santiago de Cali, in a zone known as "Pueblo Joven" during 2008. It was aimed to boys and girls with ages between 8 and 13 years and was called "Experience the magic of light and color". The main purpose was to bring the children some basic concepts on optics and to encourage them to explore science through optics. The Universidad del Valle Student Chapters designed a series of talks and practical workshops where children participated in hands-on experiments that easily explain the fundamental concepts of light phenomena. Afterwards the children presented their achievements in a small science fair offered to the community and tried to explain in their own words what they learned and built. In this work, we present the most successful experimental designs and the educational standards we tried to develop with this activity.

Valdes, Claudia; Reyes, Camilo; Osorio, Alberto; Solarte, Efrain

2010-08-01

416

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

417

The MIPS R3010 floating-point coprocessor  

Microsoft Academic Search

A description is given of the R3010 floating-point accelerator chip, a coprocessor that is based on advanced reduced-instruction-set-computer (RISC) architecture and VLSI design techniques and provides high-speed floating-point operation. The 75000-transistor hard-wired chip executes four instructions in parallel. Its performance is compared with that of available floating-point processors and its architecture is examined. The organization and implementation of the R3010

C. Rowen; M. Johnson; P. Ries

1988-01-01

418

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

419

Floating-point sparse matrix-vector multiply for FPGAs  

Microsoft Academic Search

Large, high density FPGAs with high local distributed memory bandwidth surpass the peak floating-point performance of high-end, general-purpose processors. Microprocessors do not deliver near their peak floating-point performance on efficient algorithms that use the Sparse Matrix-Vector Multiply (SMVM) kernel. In fact, it is not uncommon for microprocessors to yield only 10--20% of their peak floating-point performance when computing SMVM. We

Michael deLorimier; André DeHon

2005-01-01

420

Tests of monolithic active pixel sensors at national synchrotron light source  

NASA Astrophysics Data System (ADS)

The paper discusses basic characterization of Monolithic Active Pixel Sensors (MAPS) carried out at the X12A beam-line at National Synchrotron Light Source (NSLS), Upton, NY, USA. The tested device was a MIMOSA V (MV) chip, back-thinned down to the epitaxial layer. This 1M pixels device features a pixel size of 17×17 ?m2 and was designed in a 0.6 ?m CMOS process. The X-ray beam energies used range from 5 to 12 keV. Examples of direct X-ray imaging capabilities are presented.

Deptuch, G.; Besson, A.; Carini, G. A.; Siddons, D. P.; Szelezniak, M.; Winter, M.

2007-01-01

421

Effect of arsenic compounds on Vibrio fischeri light emission and butyrylcholinesterase activity  

Microsoft Academic Search

The effect of organic arsenic compounds and inorganic As(V) and As(III) on Vibrio fischeri luminescence and butyrylcholinesterase activity were evaluated using Microtox and microcalorimetric analysis. Organic arsenic\\u000a compounds were arsenocholine (AsC), arsenobetaine (AsB), dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and the\\u000a antibiotic 4-hydroxy-3-nitrobenzene arsonic acid (HNAA, Roxarsone(R)). HNAA, As(III) and As(V) were found to inhibit Vibrio fischeri light emission whereas

E. Fulladosa; J. Debord; I. Villaescusa; J. C. Bollinger; J. C. Murat

2007-01-01

422

Improved AC pixel electrode circuit for active matrix of organic light-emitting display  

NASA Astrophysics Data System (ADS)

In this paper, a modified four-transistor pixel circuit for active-matrix organic light-emitting displays (AMOLED) was developed to improve the performance of OLED device. This modified pixel circuit can provide an AC driving mode to make the OLED working in a reversed-biased voltage during the certain cycle. The optimized values of the reversed-biased voltage and the characteristics of the pixel circuit were investigated using AIM-SPICE. The simulated results reveal that this circuit can provide a suitable output current and voltage characteristic, and little change was made in luminance current.

Si, Yujuan; Lang, Liuqi; Chen, Wanzhong; Liu, Shiyong

2004-05-01

423

TiO 2/carbon nanotube hybrid nanostructures: Solvothermal synthesis and their visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

MWCNT/TiO 2 hybrid nanostructures were prepared via solvothermal synthesis and sol-gel method with benzyl alcohol as a surfactant. As-prepared hybrid materials were characterized by X-ray diffraction, transmission electron microscopy, UV-vis diffuse reflectance spectra and X-ray photoelectron spectroscopy. The results showed that MWCNTs were uniformly decorated with anatase nanocrystals in solvothermal condition, but MWCNTs were embedded in a majority of TiO 2 nanoparticles by sol-gel method. When the weight ratio of MWCNTs to TiO 2 was 20%, MWCNT/TiO 2 hybrid nanostructures prepared by solvothermal synthesis exhibited higher visible-light-driven photocatalytic activity than that prepared by sol-gel method. Post-annealing of MWCNT/TiO 2 nanostructures at 400 °C resulted in the formation of the carbonaceous Ti-C bonds on the interface between TiO 2 and MWCNTs, which enhanced the photoabsorbance of the hybrid materials in the visible light region and improved the visible-light degradation efficiency of methylene blue.

Tian, Lihong; Ye, Liqun; Deng, Kejian; Zan, Ling

2011-06-01

424

The amino terminal helix modulates light activated conformational changes in AsLOV2  

PubMed Central

The mechanism of light-triggered conformational change and signaling in light-oxygen-voltage (LOV) domains remains elusive in spite of extensive investigation and their use in optogenetic studies. The LOV2 domain of Avena Sativa phototropin1 (AsLOV2), a member of the Per-Arnt-Sim (PAS) family, contains an FMN chromophore that forms a covalent bond with a cysteine upon illumination. This event leads to the release of the carboxy terminal J? helix, the biological output signal. Using mutational analysis, circular dichroism and NMR, we find that the largely ignored amino terminal helix is a control element in AsLOV2’s light-activated conformational change. We further identify a direct amino-to-carboxy terminal “input-output” signaling pathway. These findings provide a framework to rationalize the LOV domain architecture, as well as the signaling mechanisms in both isolated and tandem arrangements of PAS domains. This knowledge can be applied in engineering LOV-based photoswitches, opening up new design strategies and improving existing ones.

Zayner, Josiah P.; Antoniou, Chloe; Sosnick, Tobin R.

2012-01-01

425

Light activation of genotoxic components in natural and synthetic crude oils  

SciTech Connect

Undefined components in natural and synthetically-produced petroleums elicit a genotoxic response in cultured mammalian cells after exposure to light. The NUV component of the solar spectrum is the radiation responsible for photochemical transformation. The type(s) of lesion(s) induced in DNA by the photoactivation process is mimetic of FUV light-induced genotoxic lesions (bulky adduct-like) due to the similar sensitizing abilities of either insult in cells deficient in excision repair. Because of their intimate contact with the oil in the various stages associated with the production of shale oil, process waters contain significant quantities of uv-absorbing organic materials. Chemical fractionation of a process water has been achieved using an acid/base extraction scheme and reverse-phase HPLC. Resulting fractions have been assessed for photo-induced genotoxicity using a modification of the Ames/Salmonella bioassay in which NUV light is the source of activation in place of metabolic enzymes. Chemical identification of components in a photoactive peak fraction is in progress employing an additional class fractionation scheme and GC/MS methods.

Strniste, G.

1982-01-01

426

Environment parameters and basic functions for floating-point computation  

NASA Technical Reports Server (NTRS)

A language-independent proposal for environment parameters and basic functions for floating-point computation is presented. Basic functions are proposed to analyze, synthesize, and scale floating-point numbers. The model provides a small set of parameters and a small set of axioms along with sharp measures of roundoff error. The parameters and functions can be used to write portable and robust codes that deal intimately with the floating-point representation. Subject to underflow and overflow constraints, a number can be scaled by a power of the floating-point radix inexpensively and without loss of precision. A specific representation for FORTRAN is included.

Brown, W. S.; Feldman, S. I.

1978-01-01

427

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

428

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

PubMed

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.

1996-06-01

429

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.

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

1996-01-01

430

Red light is necessary to activate the reproductive axis in chickens independently of the retina of the eye.  

PubMed

Photoperiod is essential in manipulating sexual maturity and reproductive performance in avian species. Light can be perceived by photoreceptors in the retina of the eye, pineal gland, and hypothalamus. However, the relative sensitivity and specificity of each organ to wavelength, and consequently the physiological effects, may differ. The purpose of this experiment was to test the impacts of light wavelengths on reproduction, growth, and stress in laying hens maintained in cages and to determine whether the retina of the eye is necessary. Individual cages in 3 optically isolated sections of a single room were equipped with LED strips providing either pure green, pure red or white light (red, green, and blue) set to 10 lx (hens levels). The involvement of the retina on mediating the effects of light wavelength was assessed by using a naturally blind line (Smoky Joe) of chickens. Red and white lights resulted in higher estradiol concentrations after photostimulation, indicating stronger ovarian activation, which translated into a significantly lower age at first egg when compared with the green light. Similarly, hens maintained under red and white lights had a longer and higher peak production and higher cumulative egg number than hens under green light. No significant difference in BW gain was observed until sexual maturation. However, from 23 wk of age onward, birds exposed to green light showed higher body growth, which may be the result of their lower egg production. Although corticosterone levels were higher at 20 wk of age in hens under red light, concentrations were below levels that can be considered indicative of stress. Because no significant differences were observed between blind and sighted birds maintained under red and white light, the retina of the eye did not participate in the activation of reproduction. In summary, red light was required to stimulate the reproductive axis whereas green light was ineffective, and the effects of stimulatory wavelengths do not appear to require a functional retina of the eye. PMID:24795325

Baxter, M; Joseph, N; Osborne, V R; Bédécarrats, G Y

2014-05-01

431

Active materials for automotive adaptive forward lighting Part 1: system requirements vs. material properties  

NASA Astrophysics Data System (ADS)

Adaptive Frontlighting Systems (AFS in GM usage) improve visibility by automatically optimizing the beam pattern to accommodate road, driving and environmental conditions. By moving, modifying, and/or adding light during nighttime, inclement weather, or in sharp turns, the driver is presented with dynamic illumination not possible with static lighting systems The objective of this GM-HRL collaborative research project was to assess the potential of active materials to decrease the cost, mass, and packaging volume of current electric stepper-motor AFS designs. Solid-state active material actuators, if proved suitable for this application, could be less expensive than electric motors and have lower part count, reduced size and weight, and lower acoustic and EMF noise1. This paper documents Part 1 of the collaborative study, assessing technically mature, commercially available active materials for use as actuators. Candidate materials should reduce cost and improve AFS capabilities, such as increased angular velocity on swivel. Additional benefits to AFS resulting from active materials actuators were to be identified as well such as lower part count. In addition, several notional approaches to AFS were documented to illustrate the potential function, which is developed more fully in Part 2. Part 1 was successful in verifying the feasibility of using two active materials for AFS: shape memory alloys, and piezoelectrics. In particular, this demonstration showed that all application requirements including those on actuation speed, force, and cyclic stability to effect manipulation of the filament assembly and/or the reflector could be met by piezoelectrics (as ultrasonic motors) and SMA wire actuators.

Keefe, Andrew C.; Browne, Alan L.; Johnson, Nancy L.

2011-03-01

432

Role of Efflux Pump Inhibitors on the Antibiofilm Efficacy of Calcium Hydroxide, Chitosan Nanoparticles, and Light-activated Disinfection  

Microsoft Academic Search

IntroductionThe purpose of this study was to evaluate the role of efflux pumps in altering the susceptibility of Enterococcus faecalis biofilms to calcium hydroxide (Ca(OH)2), chitosan nanoparticles, and light-activated disinfection (LAD).

Megha Upadya; Annie Shrestha; Anil Kishen

2011-01-01

433

Development and in vivo floating behavior of verapamil HCl intragastric floating tablets.  

PubMed

A novel gastro retentive controlled release drug delivery system of verapamil HCl was formulated in an effort to increase the gastric retention time of the dosage form and to control drug release. Hydroxypropylmethylcellulose (HPMC), carbopol, and xanthan gum were incorporated for gel-forming properties. Buoyancy was achieved by adding an effervescent mixture of sodium bicarbonate and anhydrous citric acid. In vitro drug release studies were performed, and drug release kinetics was evaluated using the linear regression method. The optimized intragastric floating tablet composed of 3:2 of HPMC K4M to xanthan gum exhibited 95.39% drug release in 24 h in vitro, while the buoyancy lag time was 36.2 s, and the intragastric floating tablet remained buoyant for >24 h. Zero-order and non-Fickian release transport was confirmed as the drug release mechanism from the optimized formulation (F7). X-ray studies showed that total buoyancy time was able to delay the gastric emptying of verapamil HCl intragastric floating tablet in mongrel dogs for more than 4 h. Optimized intragastric floating tablet showed no significant change in physical appearance, drug content, total buoyancy time, or in vitro dissolution pattern after storage at 40 degrees C/75% relative humidity for 3 months. PMID:19296224

Patel, Anand; Modasiya, Moin; Shah, Dushyant; Patel, Vishnu

2009-01-01

434

[The method of phytoplankton photosynthesis activity in-situ measurement based on light induced fluorescence].  

PubMed

According to the phytoplankton fluorescence induction characteristics under different light conditions, chlorophyll fluorescence as a probe for analysis of phytoplankton photosynthesis was studied. The present paper proposed a in-situ measurement method based on the chlorophyll fluorescence values Ft and Fm to get phytoplankton photosynthesis activity, Chlorella vulgaris, microcystis aeruginosa and Cyclotella meneghiniana Kiits were selected as experimental subjects, a comparison test was done between self-developed in-situ measurement system and Water PAM in lab, and the results showed that coefficients between the two methods were 0.9778, 0.8786 and 0.7953. This work provides a rapid and in-situ measurement method for phytoplankton photosynthesis activity. PMID:24369649

Liu, Jing; Liu, Wen-qing; Zhao, Nan-jing; Zhang, Yu-jun; Ma, Ming-jun; Yin, Gao-fang; Dai, Pang-da; Wang, Zhi-gang; Wang, Chun-long; Duan, Jing-bo; Yu, Xiao-ya; Fang, Li

2013-09-01

435

Visible light activated ion sensing using a photoacid polymer for calcium detection.  

PubMed

Presented here is a sensing membrane consisting of a modified merocyanine photoacid polymer and a calcium ionophore in plasticized poly(vinyl chloride). This membrane is shown to actively exchange protons with calcium ions when switched ON after illumination at 470 nm, and the exchange can be followed by UV-vis spectroscopy. The sensing membrane shows no response in the ON state when calcium ions are absent. The limit of detection of the sensor is 5.0 × 10(-4) M with an upper detection limit of 1.0 M. Thus, we demonstrate for the first time the use of a visible light activated, lipophilic photoacid polymer in an ion-sensing membrane for calcium ions, which highly discriminates potassium, sodium, and magnesium ions. PMID:24893213

Johns, Valentine K; Patel, Parth K; Hassett, Shelly; Calvo-Marzal, Percy; Qin, Yu; Chumbimuni-Torres, Karin Y

2014-07-01

436

Association Between Light-Intensity Physical Activity and Adiposity in Childhood  

PubMed Central

The purpose of this study was to examine whether the association between daily light-intensity physical activity (LPA) and total body fat mass changes during childhood. The study sample was 577 children participating in the longitudinal Iowa Bone Development Study. Body fat mass and physical activity (PA) were measured using dual energy X-ray absorptiometry (DXA) and accelerometers, respectively, at approximately 5, 8, and 11 years of age. Age- and gender-specific multivariable linear regression models were fit to predict fat mass by LPA, adjusted for actual age, birth weight, fat-free mass, height, moderate- to vigorous-intensity PA, and physical maturity (only for girls). Among boys, LPA was negatively associated with fat mass at age 11, but not age 5 or 8. Among girls, LPA was negatively associated with fat mass at ages 8 and 11, but not at age 5. LPA may have a beneficial effect against excess adiposity among older children.

Kwon, Soyang; Janz, Kathleen F.; Burns, Trudy L.; Levy, Steven M.

2011-01-01

437

High visible light activity of hydrogenated structure-engineered mixed phase titania photocatalyst  

NASA Astrophysics Data System (ADS)

The hydrogenation induced band-edge tailing with the resultant red-shift in the absorption spectrum and the creation of oxygen vacancies have incredible impact on the functionality of the monophasic titania photocatalyst in detoxification of aqueous pollutant under solar radiation. The mixed phase titania with optimum phase ratio consistently shows high activity in UV and/or visible radiation flux due to efficient separation of photo-generated charge carriers. We demonstrate that the hydrogenation of mixed phase titania (anatase-to-rutile ratio = 0.67) shows 15 times higher photocatalytic activity in the degradation of aqueous probe pollutant under the visible light, than the non-hydrogenated Degussa P25 catalyst.

Ramchiary, A.; Samdarshi, S. K.

2014-03-01

438

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

439

Light-induced anticancer activity of [RuCl2(DMSO)4] complexes.  

PubMed

The cytotoxicity and photocytotoxicity of trans-[RuCl2(DMSO)4] and cis-[RuCl2(DMSO)4] complexes was tested in two melanoma cell lines, human (SK-MEL 188) and mouse (S91). The trans isomer was found to be more effective for cell growth inhibition than its cis analogue both in the presence and in the absence of illumination. However, the antiproliferative activity of both isomers was significantly enhanced after irradiation with UVA light in comparison with their activity observed in the dark. The influence of light on the reaction of both ruthenium(II) isomers with the single-stranded hexanucleotide d(T2GGT2), chosen as a model system for DNA, was also studied using chromatography and mass spectrometry techniques. The photochemical reaction of the ruthenium(II) complexes with the oligonucleotide d(T2GGT2) resulted in the formation of Ru(G-N7)2 adducts, which was not observed in the same time scale in thermal reactions. The initial short irradiation of the inert cis isomer was found to facilitate the covalent adduct formation with d(T2GGT2) in the secondary thermal reactions and with a rate comparable to that found for the trans isomer, which is ca. 5-10 times more reactive in the dark. PMID:16279789

Brindell, Ma?gorzata; Kuli?, Ewa; Elmroth, Sofi K C; Urba?ska, Krystyna; Stochel, Grazyna

2005-11-17

440

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.

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

441

Visible light active TiO 2 films prepared by electron beam deposition of noble metals  

NASA Astrophysics Data System (ADS)

TiO 2 films prepared by sol-gel method were modified by electron beam deposition of noble metals (Pt, Pd, and Ag). Effects of noble metals on the chemical and surface characteristics of the films were studied using XPS, TEM and UV-Vis spectroscopy techniques. Photocatalytic activity of modified TiO 2 films was evaluated by studying the degradation of methyl orange dye solution under visible light UV irradiation. The result of TEM reveals that most of the surface area of TiO 2 is covered by tiny particles of noble metals with diameter less than 1 nm. Broad red shift of UV-Visible absorption band of modified photocatalysts was observed. The catalytic degradation of methyl orange in aqueous solutions under visible light illumination demonstrates a significant enhancement of photocatalytic activity of these films compared with the un-loaded films. The photocatalytic efficiency of modified TiO 2 films by this method is affected by the concentration of impregnating solution.

Hou, Xing-Gang; Ma, Jun; Liu, An-Dong; Li, De-Jun; Huang, Mei-Dong; Deng, Xiang-Yun

2010-03-01

442

Light-activated nanofibre textiles exert antibacterial effects in the setting of chronic wound healing.  

PubMed

The maintenance of an aseptic environment for chronic wounds is one of the most challenging tasks in the wound-healing process. Furthermore, the emergence of antibiotic-resistant bacterial strains is on the rise, rendering conventional treatments less effective. A new antibacterial material consisting of a polyurethane Tecophilic(™) nanofibre textile (NT) that was prepared by electrospinning and doped by a tetraphenylporphyrin (TPP) photosensitizer activated by visible light was tested for use in wound beds and bandages. In vitro experiments were performed to assess the antibacterial activity of the textile against three bacterial strains. Furthermore, the new textile was tested in 162 patients with chronic leg ulcers. A complete inhibition of in vitro growth of the three tested bacterial strains was observed on the surface of NTs that had been illuminated with visible light and was clinically demonstrated in 89 patients with leg ulcers. The application of the textiles resulted in a 35% decrease in wound size, as assessed via computer-aided wound tracing. Wound-related pain, which was estimated using a visual analogue scale, was reduced by 71%. The results of this trial reveal that the photoinactivation of bacteria through the photosensitized generation of short-lived, highly reactive singlet oxygen O(2) ((1) ?(g) ) results in relatively superficial antibacterial effects in comparison with standard antiseptic treatment options. Thus, such treatment does not interfere with the normal healing process. This method therefore represents a suitable alternative to the use of topical antibiotics and antiseptics and demonstrates potentially broad applications in medicine. PMID:22775997

Arenbergerova, Monika; Arenberger, Petr; Bednar, Marek; Kubat, Pavel; Mosinger, Jiri

2012-08-01

443

White light emission from rare earth activated yttrium silicate nanocrystalline powders and thin films  

NASA Astrophysics Data System (ADS)

We present a potential rare earth activated white-emitting nanocrystalline phosphor powders produced by combustion synthesis and report their luminescent properties and thin films deposited by pulsed laser ablation. Effects of varying the atomic concentration of rare earth dopants in Y 2SiO 5:Ce x,Tb y (0.0065 < x < 0.0085, 0.010 < y < 0.040), along with morphological, microstructural and photoluminescence (PL) properties were investigated in order to produce white-light emission close to D 65 with optimized luminescent efficiency. Characteristic electronic transitions measured from photoluminescence spectra at ?em = 544 nm ( 5D 4 ? 7F 5) in Tb 3+ and ?em = 418 nm (5d ? 2F 7/2) in Ce 3+ show that an inductive energy transfer occurs when Tb 3+ ions absorbs the energy from Ce 3+ upon excitation with long-UV photons ( ?exc = 358-380 nm). The optimal concentration for the best luminescence intensity has been obtained in Y 2SiO 5:Ce 0.0075,Tb 0.025, and the closest to daylight white emission was found with a composition of Y 2SiO 5:Ce 0.0075,Tb 0.040. These activated phosphors with two rare earth ions in the yttrium silicate host (Y 2SiO 5) represent an efficient way to produce white-light emission close to D 65 with chromaticity coordinates of x = 0.225 and y = 0.320.

Gonzalez-Ortega, J. A.; Tejeda, E. M.; Perea, N.; Hirata, G. A.; Bosze, E. J.; McKittrick, J.

2005-04-01

444

Ab initio study of TaON, an active photocatalyst under visible light irradiation.  

PubMed

Tantalum oxynitride has been studied as an active photocatalyst under visible light, using a full potential linearized augmented plane wave method within the framework of density functional theory. The electronic and optical properties of TaON are calculated using local density approximation (LDA), generalized gradient approximation (GGA), Engel-Vosko generalized gradient approximation (EVGGA) and the modified Becke-Johnson (mBJ) potential approximation to describe the exchange-correlation potential. The calculated band gap value obtained by the mBJ approximation approach (2.5 eV) is very close to the experimental result (2.5 eV). We found that hybridization among the Ta-d, O-p and N-p states results in the formation of a covalent bond between Ta-N and Ta-O. The calculated optical properties confirm that the TaON is an active photocatalyst under visible light irradiation. TaON has a high dielectric constant and the components show anisotropy in the energy range between 3.0 eV and 10.0 eV. A high refractive index of 2.47 at 632.8 nm is obtained which shows better agreement with the experimental value (2.5 at 632.8 nm) than previous results. PMID:24740793

Reshak, A H

2014-06-14

445

Parallel Optical Control of Spatiotemporal Neuronal Spike Activity Using High-Speed Digital Light Processing  

PubMed Central

Neurons in the mammalian neocortex receive inputs from and communicate back to thousands of other neurons, creating complex spatiotemporal activity patterns. The experimental investigation of these parallel dynamic interactions has been limited due to the technical challenges of monitoring or manipulating neuronal activity at that level of complexity. Here we describe a new massively parallel photostimulation system that can be used to control action potential firing in in vitro brain slices with high spatial and temporal resolution while performing extracellular or intracellular electrophysiological measurements. The system uses digital light processing technology to generate 2-dimensional (2D) stimulus patterns with >780,000 independently controlled photostimulation sites that operate at high spatial (5.4??m) and temporal (>13?kHz) resolution. Light is projected through the quartz–glass bottom of the perfusion chamber providing access to a large area (2.76?mm?×?2.07?mm) of the slice preparation. This system has the unique capability to induce temporally precise action potential firing in large groups of neurons distributed over a wide area covering several cortical columns. Parallel photostimulation opens up new opportunities for the in vitro experimental investigation of spatiotemporal neuronal interactions at a broad range of anatomical scales.

Jerome, Jason; Foehring, Robert C.; Armstrong, William E.; Spain, William J.; Heck, Detlef H.

2011-01-01

446

Visible-light Photocatalytic Activity of Titanium Dioxide/Bismuth Ferrite Heterostructures  

NASA Astrophysics Data System (ADS)

Ferroelectric polarization is believed to enhance the efficiency of a semiconductor photocatalyst, including ferroelectric/semiconductor heterojunction photocatalysts. BiFeO3, which has a narrow band gap of ?2.2 - 2.7 eV and can absorb visible light, is investigated as a ferroelectric substrate that supports a TiO2 film in a photocatalytic heterostructure. The photocatalytic activity of the TiO2/BiFeO3 heterostructure is studied in detail, using visible light irradiation. The photochemical reduction of Ag+ to Ag0 in an aqueous silver nitrate solution under illumination from a blue light emitting diode is used to characterize the activity of the heterostructures and related samples. The photocatalytic activity is quantified by measuring the heights of the reduction products using atomic force microscopy. The observation of spatially selective silver patterns on the surface of the heterostructure after reaction suggests that electrons photogenerated in the BiFeO3 substrate migrate, under the influence of ferroelectric polarization, to the TiO2 surface, where they participate in the photochemical reduction reaction. This is supported by the correlation of the reduced silver pattern and the ferroelectric domain structure as revealed by piezoresponse force microscopy (PFM). To establish correlation between out-of-plane polarity of domains and photochemical activity for both bare BiFeO3 and TiO2/BiFeO3, analysis of domain structures using PFM responses and crystallographic orientation information and comparison to reactivity patterns are made. To study the dependence of photocatalytic activity of the heterostructures on the TiO2 phase and orientation, the orientation relationships (ORs) of TiO2 and BiFeO3 are determined via the Combinatorial Substrate Epitaxy technique using electron backscatter diffraction data of each grain in a heterostructure having a thick TiO2 film on a polycrystalline BiFeO3 substrate. It is found that the three dimensional alignment of closest packed planes and directions of TiO2 and BiFeO 3 drives the epitaxial growth regardless of their interface planes. As a result, anatase grows on BiFeO3 with the OR (112)A || (111)BFO and [11¯0]A || [11¯0]BFO within 35° of [100]BFO. Rutile grows on other BiFeO 3 orientations with (100)R || (111)BFO, and with in-plane orientation being primarily [001]R || [11¯0] BFO and secondarily [001]R || [1¯21¯]BFO. Comparisons of the amounts of reduced silver on TiO2 film grains with distinct phases/orientations show that the heterostructure reactivity is approximately the same on anatase and rutile grains and is not strongly affected by the crystallographic orientation of both phases, an observation that contrasts the behavior of bulk TiO2 (under UV irradiation) but is in agreement with the behavior of UV-light absorbing ferroelectric / titania heterostructures. Collectively these observations demonstrated that TiO2 heterostructures can be engineered with visible light absorbing sensitizers that spatially separate the oxidation and reduction reaction, which will increase overall efficiencies.

Zhang, Yiling