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Last update: November 12, 2013.
1

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

Microsoft Academic Search

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 pros- thetic devices. However, these interconnects are usually the most vulnerable part of the neuroprosthetic implant that can eventually causethedevicetofail.Inthispaper,weinvestigatethefeasibilityof floating-light-activated microelectrical stimulators (FLAMES) for wireless

Ammar Abdo; Mesut Sahin

2011-01-01

2

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

PubMed Central

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

Abdo, Ammar; Sahin, Mesut

2011-01-01

3

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

2011-09-14

4

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

5

In Vitro Testing of Floating Light Activated Micro-Electrical Stimulators  

PubMed Central

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

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

2010-01-01

6

Addressable floating light activated micro-electrical stimulators for wireless neurostimulation  

Microsoft Academic Search

Stimulation of the central nervous system can be useful for treating neurological disorders. Wireless neurostim- ulating devices have the benefit that they can float in tissue and do not experience the sheering caused by tethering tension that non-wireless stimulators impose on connecting wires. An optically powered, logic controlled, CMOS microdevice that can decode telemetry data from an optical packet is

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

2011-01-01

7

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

Code of Federal Regulations, 2013 CFR

...false What are the requirements for lights on a floating hose string? 149...AND EQUIPMENT Aids to Navigation Lights on Floating Hose Strings § 149.550 What are the requirements for lights on a floating hose string?...

2013-07-01

8

Submerged (under-liquid) floating of light objects.  

PubMed

A counterintuitive submerged floating of objects lighter than the supporting liquid was observed. Polymer plates with dimensions on the order of magnitude of the capillary length were hydrophilized with cold air plasma were floated in an "under-liquid" regime (totally covered by liquid) when immersed in water or glycerol. Profiles of liquid surfaces curved by polymer plates are measured. We propose a model explaining the phenomenon. The floating of Janus plates is reported. PMID:23906242

Bormashenko, Edward; Pogreb, Roman; Grynyov, Roman; Bormashenko, Yelena; Gendelman, Oleg

2013-08-15

9

Microwave active filter using GaAs monolithic floating active inductor  

NASA Astrophysics Data System (ADS)

A broadband tunable microwave floating active inductor is proposed for microwave active filter applications. The passive inductor in the conventional LC ladder filter is replaced by the proposed floating active inductor. The advantages of this design technique include low component sensitivities and the ability to utilize the extensive knowledge of LCR filter design. The active filters can be implemented in a full MMIC form.

Zhang, Guang F.; Villegas, M. L.; Ripoll, C. S.; Gautier, J. L.

1992-07-01

10

On active vibration isolation of floating raft system  

NASA Astrophysics Data System (ADS)

A novel analytical active passive model of floating rafts, a type of special isolation structures which present high-level vibration isolation and are widely used in large ships and submarines particularly, is developed for the first time. Then the mobility matrices of the subsystems are derived, thereby a general mathematical description of this combined active passive model is realized. Based on the model, the concepts and relationships of machine control, raft control and full control are extensively discussed. The solution of the power flow transmitted into the foundation is obtained, and power transmission characteristics of the system are investigated under different control types when minimization of total power flow strategy is applied. Through numerical simulations, the control efficiencies of the different control types (machine control, raft control and full control) are compared, illustrating the efficiency of the presented model, obtaining some valuable results, and presenting some general design principles of the active floating raft isolation systems.

Niu, Junchuan; Song, Kongjie; Lim, C. W.

2005-07-01

11

Programming floating-gate circuits with UV-activated conductances  

Microsoft Academic Search

A programming technique for controlling the floating gates (FGs) in ultra-low-voltage (ULV) floating-gate circuits is presented. Simple ULV PG current-scaling and level-shifting circuits are discussed. The current scaling and level shifting are accomplished using only minimum sized transistors and floating capacitors. Floating-gate current multiplier and divider circuits are described. Measured results are provided,

Yngvar Berg; Tor S. Lande; O. Naess

2001-01-01

12

Stabilization of White Light Laser Output by a Floating Metal Grid  

NASA Astrophysics Data System (ADS)

The effect of a metal grid at a floating potential distributed between the anode and negative glow, on the stabilization of He-Cd+ hollow cathode white light laser oscillation, was investigated. The current pulses due to the transition between glow and arc discharges are suppressed by the floating grid, resulting in only a few current pulses during one hour’s running time, while several pulses a minute occurred in previous laser tube systems. The signal-to-noise ratio of the three-color laser output is distributed around 30 dB, being 46 dB for the discharge current.

Fujii, Kan-ichi; Otaka, Masahiro; Kamo, Yushi; Takashima, Masatake

1983-12-01

13

Floating Egg  

NSDL National Science Digital Library

In this activity, make an egg float in water, not by changing the egg itself, but by changing the water. Explore density, solutions, and why objects float easier in the Gulf of Mexico than in a bathtub. This activity guide includes a step-by-step instructional video.

Center, Saint L.

2013-01-17

14

Egg Float  

NSDL National Science Digital Library

In this activity, learners explore if an egg floats or sinks in salt water. Use this quick demonstration to illustrate how density affects whether things sink or float. Relate this lesson to why swimming in the ocean (saltwater) can be easier than swimming in a lake.

Houston, Children'S M.

2013-05-15

15

24 CFR 570.301 - Activity locations and float-funding.  

Code of Federal Regulations, 2013 CFR

...float-funding. The consolidated plan, action plan, and amendment submission requirements...rehabilitation, the description in the action plan or any amendment shall identify...purposes of this section and the action plan. Each activity carried...

2013-04-01

16

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

NASA Astrophysics Data System (ADS)

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 ?m de-ionized water droplet immersed in corn oil medium is actuated by a 3.21 ?W laser beam with an average intensity as low as 4.08 ?W/mm2 at a maximum speed of 85.1 ?m/s on a FEOET device. FEOET provides a promising platform for massively parallel droplet manipulation with optical images on low cost, silicon-coated glass. The FEOET device structure, fabrication, working principle, numerical simulations, and operational results are presented in this letter.

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

2008-04-01

17

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

PubMed Central

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 ?m de-ionized water droplet immersed in corn oil medium is actuated by a 3.21 ?W laser beam with an average intensity as low as 4.08 ?W?mm2 at a maximum speed of 85.1 ?m?s on a FEOET device. FEOET provides a promising platform for massively parallel droplet manipulation with optical images on low cost, silicon-coated glass. The FEOET device structure, fabrication, working principle, numerical simulations, and operational results are presented in this letter.

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

2008-01-01

18

Floating up of magnetic fields and the 11-year cyclicity of solar activity  

SciTech Connect

The characteristic time of floating up from the convection zone to the solar surface of the local strengthened magnetic fields responsible for the appearance of active regions is estimated. It is shown that this time coincides with the period of the 11-year activity cycle within the limits of accuracy of the estimates if the retardation mechanism is due to turbulent viscosity in the convection zone. For the value of ..nu../sub t/=6x10/sup 12/ cm/sup 2//sec usually used for the turbulent viscosity the floating-up time is approx.10 years, and possibly it determines the solar activity period.

Kuznetsov, V.D.; Syrovatskii, S.I.

1979-11-01

19

"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

20

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

21

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

22

Floating-Gate UVMOS inverter  

Microsoft Academic Search

This paper describes a novel technique for implementing low -voltage\\/low-power digital circuits. The threshold and supply voltage can be set to desired valueswhile exposing the chip to UV-light. UV-light activated conductances between the power supply- rails and the floating gates are used to program the desired threshold shift. The FGUVMOS inverter i s described and measurements are shown.

Yngvar Berg; Dag T. Wisland; Tor Sverre Lande

1997-01-01

23

"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

24

Performance and accuracy comparison of fixed and floating-point realizations of the Active Power Filter control algorithm  

Microsoft Academic Search

The comparison of performance and accuracy of the active power filter control algorithm realizations has been presented in the paper. The worked out algorithms are based on dq synchronous frame control strategy. The following Texas Instruments digital signal controllers were used for the realization: fixed-point TMS320F2812 and floating-point TMS320F28335. The TMS320F28335 digital signal controller is the first floating-point controller in

Marian Pasko; M. Maciazek; Dawid Bula

2008-01-01

25

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

Code of Federal Regulations, 2010 CFR

...trestles must display the following lights at night and during periods of restricted...visibility: (a) One row of yellow lights that must be: (1) Flashing 50...string's length and course. (b) Two red lights at each end of the hose...

2010-07-01

26

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

Code of Federal Regulations, 2010 CFR

...trestles must display the following lights at night and during periods of restricted...visibility: (a) One row of yellow lights that must be: (1) Flashing 50...string's length and course. (b) Two red lights at each end of the hose...

2009-07-01

27

Floating Stones  

Microsoft Academic Search

IN reference to Dr. Nordenskiold's communication re ``Floating Stones'' (No. 1577, vol. lxi.) it is a common thing to see grains of sand and small shells floating upon the waters of seas and estuaries, &c, when the surfaces are unagitated. The sand-grains must be dry; they are, therefore, only lifted and floated off by a rising tide after exposure to

Cecil Carus-Wilson

1900-01-01

28

Floating Stones  

Microsoft Academic Search

THE correspondence on ``Floating Stones'' brings to my mind a phenomenon I often noticed about ten years ago, when my work caused me to spend a good deal of time on the upper reaches of the River Mersey, of patches of earth floating down the river on the surface of the water. This occurred during the early part of the

A. W. Brightmore

1900-01-01

29

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

30

Ultraviolet light and ultraviolet light-activated composite resins  

Microsoft Academic Search

In a comparison of the UV light--activated composite resins, Estilux was polymerized to a significantly greater depth than the other composite resins. In general, Lee-fill polymerized the least. When comparing the UV light sources, the Lee light and the Duralux light did not significantly differ from each other, but both polymerized the materials tested to a significantly greater depth than

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

1981-01-01

31

With a letter-searched prime, boat primes float but swim and coat don’t: Further evidence for automatic semantic activation  

Microsoft Academic Search

Letter search (LS) on the prime typically eliminates semantic priming (swim-float) and orthographic\\/phonological (O\\/P) priming (coat-float) but not morphological priming (marked-mark). However, LS on the prime does not reduce semantic priming for low-frequency targets (Tse & Neely, 2007). These findings\\u000a suggest that semantic activation survives LS but decays during LS to a low level that can be detected only with

Matthew J. Pastizzo; James H. Neely; Chi-Shing Tse

2008-01-01

32

Floating Eggs  

Microsoft Academic Search

THE floating eggs which a correspondent in NATURE of July 14 (p. 245) describes and refers to Orthagoriscus, are apparently those of the angler or frog-fish (Lophius piscatorius), which are known to naturalists. They are laid, as Agassiz states (Proc. Amer. Acad. Arts and Sci., vol. xvii. part iii. p. 280), ``embedded in an immense ribbon-shaped band, from 2 to

Edward E. Prince

1887-01-01

33

Ultraviolet light and ultraviolet light-activated composite resins  

SciTech Connect

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

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

1981-08-01

34

Float or Sink?  

NSDL National Science Digital Library

In this water activity, learners test which objects float and which sink. Learners discover that objects behave differently in water. Learners are also introduced to the idea of "predicting" and record their predictions and observations on a chart. This activity is part of the curriculum Explore Water, related to Peep and the Big Wide World, a preschool science series on public television. The activity starts on page 41 of the PDF.

Foundation, Wgbh E.

2005-01-01

35

Programmable floating-gate MOS logic for low-power operation  

Microsoft Academic Search

In this paper we propose a novel technique for programming floating gate MOS transistors (FGMOS) in low-power design. By threshold-shifting low-power operation is possible with the cost of an extra polysilicon layer. Combining the FGMOS transistor with a UV-activated (UV) conductance gives rise to the UV-light programmable floating-gate MOS (FGUVMOS) transistor. The FGUVMOS transistor is utilized to increase the efficiency

Yngvar Berg; S. T. Lande

1997-01-01

36

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

37

Low-voltage floating-gate current mirrors  

Microsoft Academic Search

In this paper we propose a novel design of low-voltage current mirrors using floating gates. Floating gate UV-light programmable MOS transistors (FGUVMOS) are used to design current mirrors in low-voltage\\/low-power analog applications. The capacitive divider inputs to the floating gates can he utilized to reduce current mismatch due to Early effect

Yngvar Berg; Tor Sverre Lande; S. Naess

1997-01-01

38

Light activated solid-state opening switches  

SciTech Connect

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 inductive power systems.

Petr, R.A.; Kachen, G.I.; Reilly, J.P.; Schaefer, R.B. (W.J. Schafer Associates, Chelmsford, MA (United States)); Heyse, M.W. (Wright Labs., Eglin AFB, FL (United States))

1993-01-01

39

33 CFR 144.01-10 - Equipment for life floats.  

Code of Federal Regulations, 2013 CFR

...water light must be attached to the life float by a 12-thread manila or...12 feet) in length. The water light must be mounted on a bracket so that when the life float is launched, the water light will pull free of the bracket....

2013-07-01

40

33 CFR 144.01-10 - Equipment for life floats.  

Code of Federal Regulations, 2010 CFR

...water light must be attached to the life float by a 12-thread manila or...12 feet) in length. The water light must be mounted on a bracket so that when the life float is launched, the water light will pull free of the bracket....

2009-07-01

41

33 CFR 144.01-10 - Equipment for life floats.  

Code of Federal Regulations, 2010 CFR

...water light must be attached to the life float by a 12-thread manila or...12 feet) in length. The water light must be mounted on a bracket so that when the life float is launched, the water light will pull free of the bracket....

2010-07-01

42

Floating Eggs  

Microsoft Academic Search

REFERRING to the remarks of Mr. E. E. Prince in NATURE, July 28, p. 294, on the above subject, I wish to add that the spawn found by me had ``the light violet-gray tint'' and crape-like appearance he describes. I am very much on the water in harbours frequented by Lophius, but never saw any of this spawn before.

W. S. Green

1887-01-01

43

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

44

Flinking: Neither Floating nor Sinking.  

ERIC Educational Resources Information Center

Describes an activity that challenges students to make an object that, when released under water, does not float up or sink down. The main concept this activity investigates is the density of ordinary objects in comparison to the density of water. (PR)

Wilson, Roger B.

1993-01-01

45

Advanced Light Source Activity Report 2000  

SciTech Connect

This is an annual report, detailing activities at the Advanced Light Source for the year 2000. It includes highlights of scientific research by users of the facility as well as information about the development of the facility itself.

Greiner, A.; Moxon, L.; Robinson, A.; Tamura, L.

2001-04-01

46

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

47

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.

2013-05-15

48

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

49

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

Yngvar Berg; Dag T. Wisland; Tor S. Lande

1999-01-01

50

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

51

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

52

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

53

Oxygen activity dependence of the chromium (IV) population in chromium-doped forsterite crystals grown by the floating zone technique  

Microsoft Academic Search

The lasing of Cr-doped forsterite, Cr:Mg2SiO4, at 1.2 ?m has been attributed to the presence of Cr4+. The goal of this work was to determine the Cr4+Cr3+ ratios of crystals grown at different oxygen partial pressures and to compare them with a model based on point defect thermodynamics. Cr:forsterite crystals were grown by the floating zone technique with gas atmospheres

J. L. Mass; J. M. Burlitch; S. A. Markgraf; M. Higuchi; R. Dieckmann; D. B. Barber; C. R. Pollock

1996-01-01

54

Floating electrode dielectrophoresis.  

PubMed

In practice, dielectrophoresis (DEP) devices are based on micropatterned electrodes. When subjected to applied voltages, the electrodes generate nonuniform electric fields that are necessary for the DEP manipulation of particles. In this study, electrically floating electrodes are used in DEP devices. It is demonstrated that effective DEP forces can be achieved by using floating electrodes. Additionally, DEP forces generated by floating electrodes are different from DEP forces generated by excited electrodes. The floating electrodes' capabilities are explained theoretically by calculating the electric field gradients and demonstrated experimentally by using test-devices. The test-devices show that floating electrodes can be used to collect erythrocytes (red blood cells). DEP devices which contain many floating electrodes ought to have fewer connections to external signal sources. Therefore, the use of floating electrodes may considerably facilitate the fabrication and operation of DEP devices. It can also reduce device dimensions. However, the key point is that DEP devices can integrate excited electrodes fabricated by microtechnology processes and floating electrodes fabricated by nanotechnology processes. Such integration is expected to promote the use of DEP devices in the manipulation of nanoparticles. PMID:17117384

Golan, Saar; Elata, David; Orenstein, Meir; Dinnar, Uri

2006-12-01

55

Positive seal float collar  

SciTech Connect

A device for insuring a positive fluid seal between a float collar valving element and valve seat therein is disclosed. The device comprises a rubberlike tension strap or compression steel spring positioned within the float collar valve assembly for urging the valving element against the upper valve seat. Fluid pressure from above the valve assembly will overcome the force exerted on the valving element by the urging device and permit fluid to flow in a downwardly direction through the float collar valve assembly. However, when this fluid pressure above the float collar is reduced, the urging device overcomes the force exerted thereby and again urges the valving element in positive sealing engagement with the upper valve seat to preclude flow of fluid in an upperwardly direction back through the float collar valve assembly.

Bolding, B.H.

1981-09-01

56

Float-type flowmeter  

SciTech Connect

This patent describes an improvement in a float-type flowmeter for measuring the rate of a given flow of fluid. It has a float chamber; and inlet opening; means for channeling the sampled portion of the flow into the first end of the float chamber; and outlet opening; a float, located in the float chamber; and flow rate indicating means. The improvement comprises: means for ratably mounting the inlet opening so that it can be rotated to face into the flow; a rotatably mounted deflection surface, mounted so it can be deflected by the flow so as to minimize its resistance to the flow; and means for mechanically linking the deflection surface and the inlet opening so that when the deflecting surface is rotated so as to minimize its resistance to the flow, the inlet opening faces into the flow.

Daly, D.C.

1990-01-01

57

Anomalous Light Phenomena vs. Bioelectric Brain Activity  

NASA Astrophysics Data System (ADS)

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

Teodorani, M.; Nobili, G.

58

Can flexibility help you float?  

NASA Astrophysics Data System (ADS)

We consider the role of flexibility in the weight-bearing characteristics of bodies floating at an interface. Specifically, we develop a theoretical model for a two-dimensional thin floating plate that yields the maximum stable plate load and optimal stiffness for weight support. Plates small relative to the capillary length are primarily supported by surface tension, and their weight-bearing potential does not benefit from flexibility. Above a critical size comparable to the capillary length, flexibility assists interfacial flotation. For plates on the order of and larger than the capillary length, deflection from an initially flat shape increases the force resulting from hydrostatic pressure, allowing the plate to support a greater load. In this large plate limit, the shape that bears the most weight is a semicircle, which displaces the most fluid above the plate for a fixed plate length. Exact results for maximum weight-bearing plate shapes are compared to analytic approximations made in the limits of large and small plate sizes. The value of flexibility for floating to a number of biological organisms is discussed in light of our study.

Burton, L. J.; Bush, J. W. M.

2012-10-01

59

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

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 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

62

Floating-point tricks  

Microsoft Academic Search

The author discusses IEEE floating point representation that stores numbers in what amounts to scientific notation. He considers the sign bit, the logarithm function, function approximations, errors and refinements

J. F. Blinn

1997-01-01

63

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

64

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

65

Stabilized floating platforms  

DOEpatents

The subject invention is directed to a floating platform for supporting nuclear reactors and the like at selected offshore sites. The platform is provided with a stabilizer mechanism which significantly reduces the effects of wave action upon the platform and which comprises a pair of relatively small floats attached by rigid booms to the platform at locations spaced therefrom for reducing wave pitch, acceleration, and the resonance period of the wave.

Thomas, David G. (Oak Ridge, TN)

1976-01-01

66

Light Echoes in Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

The broad emission lines in the spectra of active galaxies vary in response to changes in the continuum luminosity, but with a small time delay (on the order of days to weeks) which is taken to be attributable to light-travel time effects in the broad-line region (BLR). Emission-line variability thus affords a powerful tool for determining the structure and kinematics of the BLR because the particular form of the emission-line ``light echoes'' depends on the geometry of the BLR and its orientation relative to the observer. In practice, this ``reverberation mapping'' technique requires large amounts of high-quality data. As a consequence, it is only within the last few years that significant progress has been made in this area, principally on account of massive cooperative efforts by observers. Large monitoring consortia, such as the International AGN Watch and the Lovers of Active Galaxies (LAG), have employed ground-based and space-based telescopes, notably the International Ultraviolet Explorer, to study optical and ultraviolet continuum and emission-line variability in active galaxies such as NGC 5548. I will summarize the current state of affairs in this expanding new field. I will discuss the underlying assumptions of the reverberation method, and review the progress which has been made to date. I will address remaining ambiguities, discuss new questions which have arisen, and outline plans for further observational efforts. I gratefully acknowledge support of this research at Ohio State University by the National Science Foundation (AST-8915258) and NASA (NAG5-1366 and NAG5-1824).

Peterson, B. M.

1992-05-01

67

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

68

33 CFR 146.104 - Safety and Security notice of arrival for foreign floating facilities.  

Code of Federal Regulations, 2013 CFR

...of arrival for foreign floating facilities. 146.104 Section 146...ACTIVITIES OPERATIONS Manned OCS Facilities § 146.104 Safety and Security...of arrival for foreign floating facilities. (a) General. At...

2013-07-01

69

Sink or Float? Inquiry Investigation  

NSDL National Science Digital Library

Students explore and experiment with various objects to find which materials will float or sink. They record predictions and results, and generate ideas about the properties of materials that float or sink.

70

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

71

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

72

Floating Object Recovery Study.  

National Technical Information Service (NTIS)

A study was conducted to determine a method to recover floating objects from the surface of the ocean. Model test tank investigations conducted at Stevens Institute of generating a localized flow field which would refract waves were investigated for a pos...

R. J. Helgeson

1970-01-01

73

Traumatic floating clavicle.  

PubMed

We report a case of traumatic floating clavicula in a man aged 21 years. He was admitted to our emergency department with polytrauma sustained in a motor car accident, successfully treated 21 days after the accident with bipolar open reduction and wire stabilization. PMID:23158062

Yurdakul, Emre; Salt, Ömer; Uzun, Erdal; Do?ar, Fatih; Güney, Ahmet; Durukan, Polat

2012-11-01

74

Compound floating pivot micromechanisms  

DOEpatents

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

Garcia, Ernest J. (Albuquerque, NM)

2001-04-24

75

Tracking control in space robot grasping a floating object  

Microsoft Academic Search

Tracking control and active damping control was applied in space robot capturing a floating object. The grasping operation becomes quite complicated and important for the nonlinear characteristics, such as the dynamic coupling between the manipulator and the space base, the impact of grasping and so on while space robot captures a floating object. Firstly, the dynamic model of the space

Yang Zhao; Cheng Wei; Hongliu Wang

2009-01-01

76

Light induces cortical activation and yawning in rats  

Microsoft Academic Search

We examined the effects of light stimulation on cortical activation and yawning response in anesthetized, spontaneously breathing rats. Cortical activation was assessed by means of an electrocorticogram (ECoG) and yawning response was evaluated by monitoring an intercostal electromyogram as an index of inspiratory activity and a digastric electromyogram as an indicator of mouth opening. Light stimulation elicited an arousal shift

Yoshinari Seki; Yasushi Nakatani; Ichiro Kita; Ikuko Sato-Suzuki; Mitsugu Oguri; Hideho Arita

2003-01-01

77

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,

78

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

79

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

80

Criteria for Floating I  

NASA Astrophysics Data System (ADS)

Conditions are determined under which solid bodies will float on a liquid surface in stable equilibrium, under the influence of gravity and of surface tension. These include configurations in which the density of the body exceeds the density of the ambient liquid, so that for an infinitely deep liquid in a downward gravity field there is no absolute energy minimum. Of notable interest are the results (a) that if a smooth body is held rigidly and translated downward into an infinite fluid bath through a family of fluid equilibrium configurations in a downward gravity field, the transition is necessarily discontinuous, and (b) a formal proof that there can be a free-floating locally energy minimizing configuration that does not globally minimize, even if the density of the body exceeds that of the liquid. The present work is limited to the two dimensional case corresponding to a long cylinder that is floating horizontally. The more physical three-dimensional case can be studied in a similar way, although details of behavior can change significantly. That work will appear in an independent study written jointly with T. I. Vogel.

Finn, Robert

2011-03-01

81

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

82

Light and dark active phosphodiesterase regulation in salamander rods.  

PubMed

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. PMID:1722240

Cobbs, W H

1991-09-01

83

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

84

Photo-mechanical patterning with light activated polymers.  

SciTech Connect

Light activated polymers, which are capable of mechanically responding to light, promise to offer exciting, innovative, and unique material capabilities. Such materials include: photo-radical mediated cleavage and reformation of the polymer backbone in cross-linked elastomers that results in local stress relaxation; photo-switching cross-links in shape memory polymers; and photo-isomerization of azobenzene groups contained in liquid crystal elastomers. In this paper, using our recent material model that couples multiphysical processes involved in light-activated polymers, we demonstrate that a variety of patterns can be created on light activated polymer thin films when coupling mechanical deformation with light irradiation. Here, the polymer thin film is first stretched uniaxially or biaxially. Light is then irradiated on the surface of the thin film. After light irradiation, removal external load partially recovers the initial stretching of the polymer thin film and induces patterns. The variation of the geometry of the patterns can be controlled by a variety of parameters such as initial stretching, light intensity, etc. Photo-patterning with light activated polymer therefore offers a novel way to create surface patterns.

Long, Kevin N.; Qi, H. Jerry (University of Colorado, Boulder, CO); Dunn, Martin L. (University of Colorado, Boulder, CO)

2010-11-01

85

Measurement of action spectra of light-activated processes  

NASA Astrophysics Data System (ADS)

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.

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

2006-01-01

86

The Floating Ball Paradox  

NASA Astrophysics Data System (ADS)

In capillary theory there are two kinds of surface tension. There is the surface tension at the interface between two immiscible fluids. Thomas Young [9] also allowed for there to be a surface tension associated with a liquid-solid interface. He proceeded to use a balance of forces argument to derive the well-known contact angle condition along a liquid-liquid-solid intersection. The validity of this argument has recently been called into question by R. Finn [6]. A floating ball experiment discussed in that paper leads to an apparent paradox. We address this issue.

Wente, Henry C.

2008-11-01

87

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

88

Acousto-optic light deflectors using optical activity in paratellurite  

Microsoft Academic Search

Light deflector designs which use the anomalously low shear wave acoustic velocity and high acousto-optic figure of merit in single-crystal paratellurite, first proposed by Uchida and Ohmachi, have been made practical by exploiting this material's birefringence to circularly polarized light. Dixon's equations for Bragg interaction in birefringent materials are found to be equally applicable to optically active materials when linearly

A. W. Warner; D. L. White; W. A. Bonner

1972-01-01

89

National Synchrotron Light Source 2008 Activity Report  

SciTech Connect

Funded by the U.S. Department of Energy's Office of Basic Energy Sciences, the National Synchrotron Light Source (NSLS) is a national user facility that operates two electron storage rings: X-Ray (2.8 GeV, 300 mA) and Vacuum Ultraviolet (VUV) (800 mev, 1.0A). These two rings provide intense light spanning the electromagnetic spectrum -- from very long infrared rays to ultraviolet light and super-short x-rays -- to analyze very small or highly dilute samples. The properties of this light, and the specially designed experimental stations, called beamlines, allow scientists in many diverse disciplines of research to perform experiments not possible at their own laboratories. Each year, about 2,200 scientists from more than 400 universities and companies use the NSLS for research in such diverse fields as biology, physics, chemistry, geology, medicine, and environmental and materials sciences. For example, researchers have used the NSLS to examine the minute details of computer chips, decipher the structures of viruses, probe the density of bone, determine the chemical composition of moon rocks, and reveal countless other mysteries of science. The facility has 65 operating beamlines, with 51 beamlines on the X-Ray Ring and 14 beamlines on the VUV-Infrared Ring. It runs seven days a week, 24 hours a day throughout the year, except during periods of maintenance and studies. Researchers are not charged for beam time, provided that the research results are published in open literature. Proprietary research is conducted on a full-cost-recovery basis. With close to 1,000 publications per year, the NSLS is one of the most prolific scientific facilities in the world. Among the many accolades given to its users and staff, the NSLS has won nine R&D 100 Awards for innovations ranging from a closed orbit feedback system to the first device able to focus a large spread of high-energy x-rays. In addition, a visiting NSLS researcher shared the 2003 Nobel Prize in Chemistry for work explaining how one class of proteins helps to generate nerve impulses.

Nasta,K.

2009-05-01

90

33 CFR 146.103 - Safety and Security notice of arrival for U.S. floating facilities.  

Code of Federal Regulations, 2013 CFR

...of arrival for U.S. floating facilities. 146.103 Section 146...ACTIVITIES OPERATIONS Manned OCS Facilities § 146.103 Safety and Security...of arrival for U.S. floating facilities. (a) General. At...

2013-07-01

91

Evaluation of Minimum Approach Light System for Lower Activity Airports.  

National Technical Information Service (NTIS)

Flight tests were conducted during actual Category I weather conditions to determine the suitability of three approach light patterns in providing guidance for aircraft approach speeds of 125 knots using ILS into lower activity airports. Each pattern test...

T. H. Paprocki R. F. Gates

1966-01-01

92

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

93

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

94

Float-thermostatic trap prevents steam loss  

SciTech Connect

This article focuses on the energy efficiency of a float-thermostatic steam trap which prevents steam loss. This float-thermostatic steam trap was awarded Top Honors in the steam traps category in the 1982 Chemical Processing Vaaler competition because of the trap's lack of steam loss, its in-line installation, and its ability to be maintained in-line. The energy efficient trap features a float operated mechanism that modulates with the load and always maintains a condensate level above the main valve to prevent steam leakage, and a balance pressure thermostatic air vent that immediately and continuously discharges all non-condensibles. Other features include resistance to dirt plugging and freeze damage for long reliable service; fail-safe operation; all-stainless steel corrosion resistant internals; light weight stainless steel case with forged cover; and convenient top and bottom inlet with 1/2'' threaded or socket weld connections. The traps will save from 2 to 5 lb/hr of steam, compared to conventional traps. Annual savings are estimated at between $175 and $438 per trap, with steam costing $10 per thousand pounds.

Not Available

1982-11-01

95

Blue light stimulates cognitive brain activity in visually blind individuals.  

PubMed

Light regulates multiple non-image-forming (or nonvisual) circadian, neuroendocrine, and neurobehavioral functions, via outputs from intrinsically photosensitive retinal ganglion cells (ipRGCs). Exposure to light directly enhances alertness and performance, so light is an important regulator of wakefulness and cognition. The roles of rods, cones, and ipRGCs in the impact of light on cognitive brain functions remain unclear, however. A small percentage of blind individuals retain non-image-forming photoreception and offer a unique opportunity to investigate light impacts in the absence of conscious vision, presumably through ipRGCs. Here, we show that three such patients were able to choose nonrandomly about the presence of light despite their complete lack of sight. Furthermore, 2 sec of blue light modified EEG activity when administered simultaneously to auditory stimulations. fMRI further showed that, during an auditory working memory task, less than a minute of blue light triggered the recruitment of supplemental prefrontal and thalamic brain regions involved in alertness and cognition regulation as well as key areas of the default mode network. These results, which have to be considered as a proof of concept, show that non-image-forming photoreception triggers some awareness for light and can have a more rapid impact on human cognition than previously understood, if brain processing is actively engaged. Furthermore, light stimulates higher cognitive brain activity, independently of vision, and engages supplemental brain areas to perform an ongoing cognitive process. To our knowledge, our results constitute the first indication that ipRGC signaling may rapidly affect fundamental cerebral organization, so that it could potentially participate to the regulation of numerous aspects of human brain function. PMID:23859643

Vandewalle, Gilles; Collignon, Olivier; Hull, Joseph T; Daneault, Véronique; Albouy, Geneviève; Lepore, Franco; Phillips, Christophe; Doyon, Julien; Czeisler, Charles A; Dumont, Marie; Lockley, Steven W; Carrier, Julie

2013-07-16

96

Flow-induced forces on free-floating macrophytes  

Microsoft Academic Search

Free-floating macrophytes have buoyant petioles and unanchored roots; certain species are highly invasive, owing to characteristics\\u000a such as high growth rates and the formation of dense floating mats that drift on wind and water currents. Water hyacinth (Eichhornia crassipes) is one example; its invasion of tropical and subtropical freshwater systems worldwide harms native ecosystems and impedes\\u000a human activities. This research

Maureen Downing-Kunz; Mark Stacey

2011-01-01

97

CASES Online: Lights Out! - A Circuit Activity  

NSDL National Science Digital Library

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

Toebbe, Jonathan

2010-06-22

98

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

99

Anchoring floating structural body in deep water  

Microsoft Academic Search

This patent describes a deep water anchoring system for oil drilling platforms and other deep water structures, comprising: a structural body floating at the surface of a body of water; an intermediate floating member directly under and spaced from the floating structural body; intermediate floating member submerged below the surface of the body of water a distance sufficient to be

Kalpins

1987-01-01

100

Ecological measurements of light exposure, activity, and circadian disruption  

PubMed Central

Circadian rhythms are biological rhythms that repeat at approximately 24 hours. In humans, circadian rhythms have an average period of 24.2 hours. The 24-hour patterns of light and dark on the retina synchronize circadian rhythms to the local time on earth. Lighting characteristics affecting circadian rhythms are very different than those affecting visual responses. Lack of synchronization between the endogenous clock and the local time has been associated with a host of maladies. Therefore, it is important to measure circadian light exposures over the course of the 24-hour day and to be able to assess circadian entrainment and disruption in actual living environments. Presented is an overview of the recently developed Daysimeter, a personal measurement device for recording activity and circadian light-exposure. When the Daysimeter is worn on the head, two light sensors near the eye are used to estimate circadian light (CLA) exposures over extended periods of time. Phasor analysis combines the measured periodic activity-rest patterns with the measured periodic light-dark patterns to assess behavioural circadian entrainment/disruption. As shown, day-shift and rotating-shift nurses exhibit remarkably different levels of behavioural circadian entrainment/disruption. These new ecological measurement and analysis techniques may provide important insights into the relationship between circadian disruption and well-being.

Miller, D; Bierman, A; Figueiro, MG; Schernhammer, ES; Rea, MS

2013-01-01

101

Light-mode condensation in actively-mode-locked lasers.  

PubMed

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 of noninteracting bosons in an external potential. The light-mode BEC transition occurs for a mode-locking modulation that has a power law dependence on time with an exponent smaller than 2. PMID:20482109

Weill, Rafi; Fischer, Baruch; Gat, Omri

2010-04-28

102

Controlling the enzymatic activity of a restriction enzyme by light  

PubMed Central

For many applications it would be desirable to be able to control the activity of proteins by using an external signal. In the present study, we have explored the possibility of modulating the activity of a restriction enzyme with light. By cross-linking two suitably located cysteine residues with a bifunctional azobenzene derivative, which can adopt a cis- or trans-configuration when illuminated by UV or blue light, respectively, enzymatic activity can be controlled in a reversible manner. To determine which residues when cross-linked show the largest “photoswitch effect,” i.e., difference in activity when illuminated with UV vs. blue light, > 30 variants of a single-chain version of the restriction endonuclease PvuII were produced, modified with azobenzene, and tested for DNA cleavage activity. In general, introducing single cross-links in the enzyme leads to only small effects, whereas with multiple cross-links and additional mutations larger effects are observed. Some of the modified variants, which carry the cross-links close to the catalytic center, can be modulated in their DNA cleavage activity by a factor of up to 16 by illumination with UV (azobenzene in cis) and blue light (azobenzene in trans), respectively. The change in activity is achieved in seconds, is fully reversible, and, in the case analyzed, is due to a change in V max rather than K m.

Schierling, Benno; Noel, Ann-Josee; Wende, Wolfgang; Hien, Le Thi; Volkov, Eugeny; Kubareva, Elena; Oretskaya, Tatiana; Kokkinidis, Michael; Rompp, Andreas; Spengler, Bernhard; Pingoud, Alfred

2010-01-01

103

Light-Activated Ion Channels for Remote Control of Neural Activity  

PubMed Central

Light-activated ion channels provide a new opportunity to precisely and remotely control neuronal activity for experimental applications in neurobiology. In the past few years, several strategies have arisen that allow light to control ion channels and therefore neuronal function. Light-based triggers for ion channel control include caged compounds, which release active neurotransmitters when photolyzed with light, and natural photoreceptive proteins, which can be expressed exogenously in neurons. More recently, a third type of light trigger has been introduced: a photoisomerizable tethered ligand that directly controls ion channel activity in a light-dependent manner. Beyond the experimental applications for light-gated ion channels, there may be clinical applications in which these light-sensitive ion channels could prove advantageous over traditional methods. Electrodes for neural stimulation to control disease symptoms are invasive and often difficult to reposition between cells in tissue. Stimulation by chemical agents is difficult to constrain to individual cells and has limited temporal accuracy in tissue due to diffusional limitations. In contrast, ion channels that can be directly activated with light allow control with unparalleled spatial and temporal precision. The goal of this chapter is to describe light-regulated ion channels and how they have been tailored to control different aspects of neural activity, and how to use these channels to manipulate and better understand development, function, and plasticity of neurons and neural circuits.

Chambers, James J.; Kramer, Richard H.

2009-01-01

104

Blue light activates a specific protein kinase in higher plants.  

PubMed

Blue light mediates the phosphorylation of a membrane protein in seedlings from several plant species. When crude microsomal membrane proteins from dark-grown pea (Pisum sativum L.), sunflower (Helianthus annuus L.), zucchini (Cucurbita pepo L.), Arabidopsis (Arabidopsis thaliana L.), or tomato (Lycopersicon esculentum L.) stem segments, or from maize (Zea mays L.), barley (Hordeum vulgare L.), oat (Avena sativa L.), wheat (Triticum aestivum L.), or sorghum (Sorghum bicolor L.) coleoptiles are illuminated and incubated in vitro with [gamma-(32)P]ATP, a protein of apparent molecular mass from 114 to 130 kD is rapidly phosphorylated. Hence, this system is probably ubiquitous in higher plants. Solubilized maize membranes exposed to blue light and added to unirradiated solubilized maize membranes show a higher level of phosphorylation of the light-affected protein than irradiated membrane proteins alone, suggesting that an unirradiated substrate is phosphorylated by a light-activated kinase. This finding is further demonstrated with membrane proteins from two different species, where the phosphorylated proteins are of different sizes and, hence, unambiguously distinguishable on gel electrophoresis. When solubilized membrane proteins from one species are irradiated and added to unirradiated membrane proteins from another species, the unirradiated protein becomes phosphorylated. These experiments indicate that the irradiated fraction can store the light signal for subsequent phosphorylation in the dark. They also support the hypothesis that light activates a specific kinase and that the systems share a close functional homology among different higher plants. PMID:16653043

Reymond, P; Short, T W; Briggs, W R

1992-10-01

105

Evaluation and floating enhancement of levodopa sustained release floating minitablets coated with insoluble acrylic polymer.  

PubMed

This article describes the in vitro evaluation and the enhancement of the floating properties of coated sustained release (SR) minitablets (MTs). The evaluated system consisted of a 3-mm drug-containing gas-generating core prepared by melt granulation and subsequent compression, which was then coated with a flexible polymeric membrane. Eudragit RL30D and acetyl triethylcitrate were used as a film former and a plasticizer, respectively. The coating level was fixed at 20% (wt/wt). The optimally coated floating MTs floated within 10 min and remained buoyant for more than 13 h, regardless of the pH of the test medium. By evaluating the dissolution profiles of levodopa at different pH, it was found that the release of levodopa was sustained for more than 12 h regardless of the pH, even if the coating did not cancel the effect of the pH-dependent solubility of the active drug. Finally, the robustness of the coated floating MTs was assessed by testing the drug release variability in function of the stirring conditions during dissolution tests. PMID:18618310

Goole, J; Amighi, K; Vanderbist, F

2008-08-01

106

Effects of light sources and visible light-activated titanium dioxide photocatalyst on bleaching.  

PubMed

The objective of this study was to evaluate, using methylene blue (MB), the effects of various light sources on the bleaching action of hydrogen peroxide (H(2)O(2)) with two titanium dioxide (TiO(2)) photocatalysts - an ultraviolet light-activated TiO(2) photocatalyst (UVTiO(2)) versus a visible light-activated TiO(2) photocatalyst (VL-TiO(2)). Five experimental solutions (VL-TiO(2)+H(2)O(2), UV-TiO(2)+H(2)O(2), H(2)O(2), VL-TiO(2), UV-TiO(2)) were prepared by mixing varying concentrations of H(2)O(2 )and/or TiO(2 )photocatalyst with MB solution. For H(2)O(2)-containing solutions (VL-TiO(2)+H(2)O(2), UV-TiO(2)+H(2)O(2), and H(2)O(2)), the concentration of H(2)O(2) was adjusted to 3.5%. For the four different light sources, low- and high-intensity halogen lamps and blue LED LCUs were used. All the experimental solutions were irradiated by each of the light sources for 7 minutes, and the absorbance at 660 nm was measured every 30 seconds to determine the concentration of MB as an indicator of the bleaching effect. On the interaction between the effects of light source and bleaching treatment, the high-intensity halogen with VL-TiO(2)+H(2)O(2) caused the most significant reduction in MB concentration. On the effect of light sources, the halogen lamps resulted in a greater bleaching effect than the blue LED LCUs. PMID:20019420

Suyama, Yuji; Otsuki, Masayuki; Ogisu, Shinichiro; Kishikawa, Ryuzo; Tagami, Junji; Ikeda, Masaomi; Kurata, Hiroshi; Cho, Takahiro

2009-11-01

107

Floating intake reduces pump damage  

SciTech Connect

The solution to a costly sand erosion problem at the Grande Dixence hydroelectric project in Switzerland turned out to be as simple as a floating pump. The 726-MW Grande Dixence project drains a 350-square-kilometer reach of the Zermatt and Herens valleys in the southwestern Swiss Alps. About half of the drainage area is covered by active glaciers. Because the glaciers in Zermatt Valley are so low in altitude, their water is collected in Z`mutt Reservoir at the base of the Matterhorn, then pumped up 500 meters for transport to the main Grande Disence Reservoir near Sion. The glacier water is heavily laden with sand. In spite of a gravel pass and a desilter, the 700,000-acubic-meter Z`mutt Reservoir receives large quantities of sand. The sand tends to remain in solution because of the low water temperatures (1 to 2 degrees Centigrade). In the original intake system, the sand would be sucked into the pump intakes, causing extensive erosion to the pump wheels and an expensive yearly program of repair. (Pump damage averaged 200,000 Swiss Francs ($284,000 U.S.) per year between 1980 and 1985.)

Kronig, A.

1993-12-31

108

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

109

[The effect of light craniocerebral trauma on cardiac activity].  

PubMed

Heart activity was studied by electrocardiography (ECG) and variation pulsometry in patients aged from 17 to 44 1-21 days after light brain trauma. Homeostatic imbalance between suprasegmental structures of the brain was established. Disintegrated activity of these structures results in increase of ECG and variation pulsometry may be additional criteria for assessment of interactions between sympathetic nervous system and different levels of heart rhythm regulation. PMID:8030322

Polishchuk, N E; Nasalika, B G; Skliar, A A

110

Targeting lymphocyte activation through the lymphotoxin and LIGHT pathways  

Microsoft Academic Search

Summary: Cytokines mediate key communication pathways essential for regulation of immune responses. Full activation of antigen-responding lymphocytes requires cooperating signals from the tumor necrosis factor (TNF)-related cytokines and their specific receptors. LIGHT, a lymphotox- in-b (LTb)-related TNF family member, modulates T-cell activation through two receptors, the herpesvirus entry mediator (HVEM) and indirectly through the LT-b receptor. An unexpected finding revealed

Carl F. Ware

2008-01-01

111

Artificial light sources and their influence on physical activity and energy expenditure of laying hens  

Microsoft Academic Search

1. The influence of fluorescent and incandescent artificial lighting in a 16L:8D day\\/night schedule on number and intensity of movements, and on total, resting and activity?related energy expenditure was investigated.2. Fluorescent light showed the same positive correlation between light intensity and physical activity at all activity levels as was found previously for incandescent light.3. Light?dependent physical activity under fluorescent light

F. M. G. Boshouwers; Elly Nicaise

1993-01-01

112

Screening for enzyme activity in turbid suspensions with scattered light.  

PubMed

New screening techniques for improved enzyme variants in turbid media are urgently required in many industries such as the detergent and food industry. Here, a new method is presented to measure enzyme activity in different types of substrate suspensions. This method allows a semiquantitative determination of protease activity using native protein substrates. Unlike conventional techniques for measurement of enzyme activity, the BioLector technology enables online monitoring of scattered light intensity and fluorescence signals during the continuous shaking of samples in microtiter plates. The BioLector technique is hereby used to monitor the hydrolysis of an insoluble protein substrate by measuring the decrease of scattered light. The kinetic parameters for the enzyme reaction (V(max,app) and K(m,app)) are determined from the scattered light curves. Moreover, the influence of pH on the protease activity is investigated. The optimal pH value for protease activity was determined to be between pH 8 to 11 and the activities of five subtilisin serine proteases with variations in the amino acid sequence were compared. The presented method enables proteases from genetically modified strains to be easily characterized and compared. Moreover, this method can be applied to other enzyme systems that catalyze various reactions such as cellulose decomposition. PMID:21302369

Huber, Robert; Wulfhorst, Helene; Maksym, Lukas; Stehr, Regina; Pöhnlein, Martin; Jäger, Gernot; Spiess, Antje C; Büchs, Jochen

2011-02-07

113

Floating units cut production costs  

SciTech Connect

Nine operating semisubmersible and tanker production platform facilities are currently supplying the technology and experiential data necessary for development of floating production systems for depth applications of 1000 to 10,000 ft. Sedco-Hamilton Production Services has developed a 4-well deepwater system consisting of a floating tanker or semi moored on short lines to 4 permanent catenary moored springbuoys. The platform is linked to a seabed tree array through the hull centerline via a flexible, retrievable production riser bundle. Costs associated with floating production platforms normally are lower than those of fixed platforms. A major factor is the decision to convert an existing drilling rig into the production mode or alternatively opt for a new build.

Homer, A.

1983-05-01

114

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

2013-05-07

115

Light-mediated activities of thiarubrines against human immunodeficiency virus.  

PubMed

Two thiarubrines (dithiacyclohexadienes), which were isolated recently from species of Asteraceae, were investigated for light-mediated antiviral activity against human immunodeficiency virus (HIV-1). Both compounds (thiarubrines A and D) showed good anti-HIV activity, in micromolar concentrations, which was dependent upon UVA radiation. They showed no anti-viral activity in the dark, and only weak visible light-mediated activity, despite the significant absorbance of these compounds in the 480 nm region. The resulting inactivated virus was unable to replicate in cell cultures, as indicated by loss of cytopathogenicity, the absence of cells expressing HIV-1 antigens and lack of production of HIV-1 p24 protein. Although this antiviral activity was not as efficient as that shown by the photoactive plant thiophene, alpha-terthienyl, both thiarubrines demonstrated increased activity when the serum component of the virus stock was reduced. This suggested that a component of bovine serum interfered to some extent with the anti-HIV activity. PMID:8389484

Hudson, J B; Balza, F; Harris, L; Towers, G H

1993-04-01

116

Goodyear Scrap Tire Floating Breakwater Concepts.  

National Technical Information Service (NTIS)

Scrap tires are proposed as a construction material for building large floating breakwater devices. The Goodyear scrap tire floating breakwater assemblies are formed by securing together modular bundles of tightly interlocked scrap tires with high strengt...

R. D. Candle

1974-01-01

117

Battery Charging in Float vs. Cycling Environments.  

National Technical Information Service (NTIS)

In lead-acid battery systems, cycling systems are often managed using float management strategies. There are many differences in battery management strategies for a float environment and battery management strategies for a cycling environment. To complica...

G. P. Corey

2000-01-01

118

Rhythmic motor activity responses of the California fiddler crab Uca crenulata to artificial light conditions  

Microsoft Academic Search

Uca crenulata, the California species of fiddler crab, was exposed to artificial light conditions to separate the influence of the light cycle from that of the tidal input on its rhythmic motor activity. Under both constant light and light-dark cycles, rhythmic activity was demonstrated in only 50% of the experimental crabs; the activity of the remaining 50% was random. Individuals

H.-W. Honegger

1973-01-01

119

Active spectral control of DUV light sources for OPE minimization  

NASA Astrophysics Data System (ADS)

The variation of CD with pitch, or Optical Proximity Effect (OPE), in an imaging system shows a behavior that is characteristic of the imaging and process conditions and is sensitive to variations in those conditions. Maintaining stable process conditions can improve the effectiveness of mask Optical Proximity Correction (OPC). One of the factors which affects the OPE is the spectral bandwidth of the light source. To date, passive bandwidth stabilization techniques have been effective in meeting OPE control requirements. However, future tighter OPE specifications will require advanced bandwidth control techniques. This paper describes developments in active stabilization of bandwidth in Cymer XLA and 7010 lasers. State of the art on board metrology, used to accurately measure E95 bandwidth, has enabled a new array of active control solutions to be deployed. Advanced spectral engineering techniques, including sophisticated control algorithms, are used to stabilize and regulate the bandwidth of the light source while maintaining other key performance specifications.

Dunstan, Wayne J.; Jacques, Robert; Rafac, Robert J.; Rao, Rajasekhar; Trintchouk, Fedor

2006-04-01

120

Recoverin Regulates Light-dependent Phosphodiesterase Activity in Retinal Rods  

PubMed Central

The Ca2+-binding protein recoverin may regulate visual transduction in retinal rods and cones, but its functional role and mechanism of action remain controversial. We compared the photoresponses of rods from control mice and from mice in which the recoverin gene was knocked out. Our analysis indicates that Ca2+-recoverin prolongs the dark-adapted flash response and increases the rod's sensitivity to dim steady light. Knockout rods had faster Ca2+ dynamics, indicating that recoverin is a significant Ca2+ buffer in the outer segment, but incorporation of exogenous buffer did not restore wild-type behavior. We infer that Ca2+-recoverin potentiates light-triggered phosphodiesterase activity, probably by effectively prolonging the catalytic activity of photoexcited rhodopsin.

Makino, Clint L.; Dodd, R.L.; Chen, J.; Burns, M.E.; Roca, A.; Simon, M.I.; Baylor, D.A.

2004-01-01

121

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

122

Investigation of activity release during light water reactor core meltdown  

Microsoft Academic Search

A test facility was developed for the determination of activity release and of aerosol characteristics under realistic light water reactor core melting conditions. It is composed of a high-frequency induction furnace, a ThOâ crucible system, and a collection apparatus consisting of membrane and particulate filters. Thirty-gram samples of a representative core material mixture (corium) were melted under air, argon, or

H. Albrecht; V. Matschoss; H. Wild

1978-01-01

123

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

124

FINDING PIPING LEAKS WITH SEALED MILLICURIE FLOATS  

Microsoft Academic Search

A method is described in which a sealed radioisotopetagged float is used ; to find leaks in piping which runs under concrete floors or fills. The current ; caused by the leak causes the float to seek out the leak. Early studies with ; this method employed a sponge-rubber ball as a float. Spun stainless steel balls ; are being

R. E. Black; W. Kerwick

1960-01-01

125

Optimistic Parallelization of Floating-Point Accumulation  

Microsoft Academic Search

Floating-point arithmetic is notoriously non- associative due to the limited precision representation which demands intermediate values be rounded to fit in the available precision. The resulting cyclic dependency in floating-point ac- cumulation inhibits parallelization of the computation, including efficient use of pipelining. In practice, however, we observe that floating-point operations are \\

Nachiket Kapre; André Dehon

2007-01-01

126

Have Floating Rates Been a Success?  

ERIC Educational Resources Information Center

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

Higham, David

1983-01-01

127

New directions in floating-point arithmetic  

Microsoft Academic Search

This article briefly describes the history of floating-point arithmetic, the development and features of IEEE standards for such arithmetic, desirable features of new implementations of floating-point hardware, and discusses work- in-progress aimed at making decimal floating-point arithmetic widely available across many architectures, operating systems, and programming languages.

Nelson H. F. Beebe

128

Smoking-Cue Induced Brain Activation In Adolescent Light Smokers  

PubMed Central

Purpose Using fMRI, we examined whether or not adolescents with low levels of nicotine exposure (light smokers) display neural activation in areas shown to be involved with addiction in response to smoking-related stimuli. Design/Setting/Participants Twelve adolescent light smokers (aged 13 to17, smoked 1 to 5 cigarettes per day) and 12 non-smokers (ages 13 to 17, never smoked a cigarette) from the San Francisco Bay Area underwent fMRI scanning. During scanning they viewed blocks of photographic smoking and control cues. Smoking cues consisted of pictures of people smoking cigarettes and smoking-related objects such as lighters and ashtrays. Neutral cues consisted of everyday objects and people engaged in everyday activities. Findings For smokers, smoking cues elicited greater activation than neutral cues in the mesolimbic reward circuit (left anterior cingulate (T=7.88, p<.001), right hippocampus (T=6.62, p<.001) and right parahippocampal gyrus (T=4.70, p<.001)). We found activation from smoking cues versus neutral cues within both the left and right frontal medial orbital regions (T=5.09, p<.001 and T=3.94, p=.001 respectively), which may be unique to adolescents. Non-smokers showed no significant difference in activation between smoking-related cues and neutral cues. Conclusions Our finding that smoking cues produced activation in adolescent light smokers in brain regions seen in adult and heavy teen smokers suggests that even at low levels of smoking, adolescents exhibit heightened reactivity to smoking cues. This paper adds to the existing literature suggesting that nicotine dependence may begin with exposure to low levels of nicotine, underscoring the need for early intervention among adolescent smokers.

Rubinstein, Mark L.; Luks, Tracy L.; Moscicki, Anna-Barbara; Dryden, Wendy; Rait, Michelle A.; Simpson, Gregory V.

2010-01-01

129

The Floating Siphon - an Effective  

Microsoft Academic Search

A simple device, which can be used in place of a syringe pump, has been suggested for high dilution experiments. The flasks containing the solutions to be mixed are equipped with siphons and placed on the top of a styrofoam cylinder, or other floater. The styrofoam cylinder floats in a beaker containing water. A glass rod is threaded through a

Alexander Kolchinski

1997-01-01

130

40mm Floating Flare Development.  

National Technical Information Service (NTIS)

The 40mm Floating Flare can be launched from either the M79 or the M203 Grenade Launcher and provides troops with a standoff capability for marking a target or position in inundated areas during hours of darkness. The flotation capability is achieved by a...

D. W. Renfroe

1973-01-01

131

Status, trends of floating systems  

SciTech Connect

The design philosophy of floating production sytems is discussed briefly. Some of the major constraints and trade-offs involved in the design concept selection and development are discussed. Four concepts, single anchor leg, multibore riser floating production system, multibore riser floating production system/loading system, and tension leg platforms, are considered to be potentially the most attractive concepts and those that embrace all the relevant design features. The factors which determine which field development scenario, satellite wells or cluster/template wells (or perhaps a combination of these), is chosen for development of an offshore site, are discussed. Mechanical well-design requirements which must be met for either type of well development are considered. Other aspects of deepwater production that are discussed are: flowline system, installation method, riser behavior, floating unit, anchoring out, and offloading and storage. Certain foreseeable needs for the future trend of offshore drilling including technological advances to deal with deeper water, different products, and larger fields are set forth. (BLM)

Vincken, L.M.J.

1981-01-01

132

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

133

Vesicular arbuscular mycorrhizae in floating wetland mat communities dominated by Typha  

Microsoft Academic Search

Low levels of vesicular arbuscular mycorrhizae were present in floating mats dominated by clones of Typha angustifolia L., T. x glauca Godr., and T. latifolia L. Floating mats composed of rhizomes (underwater-ground stems with high starch accumulation), roots, decaying organic matter, and wind deposited soil, easily supported human activities. The majority of roots isolated from the root cores were connected

Dwayne L. Stenlund; Iris D. Charvat

1994-01-01

134

DEVELOPMENT OF THE FLOATING SULPHUR BIOFILM REACTOR FOR SULPHIDE OXIDATION IN BIOLOGICAL WATER TREATMENT SYSTEMS  

Microsoft Academic Search

The formation of floating sulphur biofilm was observed in the microbial ecology studies of tannery ponds undertaken by the Environmental Biotechnology Group at Rhodes University. This was related to the steep Redox gradients established at the air\\/water interface of anaerobic, organically loaded and actively sulphate reducing systems. This study investigated the potential for applying these observations in developing a floating

J. B. Molwantwa; S. E. Coetser; R. Heath; P. D. Rose

2004-01-01

135

33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147.815 Section 147.815...CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The...

2010-07-01

136

33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.  

Code of Federal Regulations, 2010 CFR

...2009-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147.815 Section 147.815...CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The...

2009-07-01

137

33 CFR 147.815 - ExxonMobil Hoover Floating OCS Facility safety zone.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false ExxonMobil Hoover Floating OCS Facility safety zone. 147.815 Section 147.815...CONTINENTAL SHELF ACTIVITIES SAFETY ZONES § 147.815 ExxonMobil Hoover Floating OCS Facility safety zone. (a) Description. The...

2013-07-01

138

Preparation of visible light active S-doped TiO2 photocatalysts and their photocatalytic activities  

Microsoft Academic Search

Although titanium dioxide photocatalysts having an anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under UV light. To utilize solar light which has a large amount of visible light, the development of the photocatalysts whose activities show under visible light is one of the most important strategies. We have

T. Ohno

2004-01-01

139

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

140

Glucocorticoid receptor activity regulates light adaptation in the zebrafish retina.  

PubMed

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, gr (s357) , 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 gr (s357) 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. PMID:24068988

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

2013-09-24

141

Changes in the colour of light cue circadian activity  

PubMed Central

The discovery of melanopsin, the non-visual opsin present in intrinsically photosensitive retinal ganglion cells (ipRGCs), has created great excitement in the field of circadian biology. Now, researchers have emphasized melanopsin as the main photopigment governing circadian activity in vertebrates. Circadian biologists have tested this idea under standard laboratory, 12h Light: 12h Dark, lighting conditions that lack the dramatic daily colour changes of natural skylight. Here we used a stimulus paradigm in which the colour of the illumination changed throughout the day, thus mimicking natural skylight, but luminance, sensed intrinsically by melanopsin containing ganglion cells, was kept constant. We show in two species of cichlid, Aequidens pulcher and Labeotropheus fuelleborni, that changes in light colour, not intensity, are the primary determinants of natural circadian activity. Moreover, opponent-cone photoreceptor inputs to ipRGCs mediate the sensation of wavelength change, and not the intrinsic photopigment, melanopsin. These results have implications for understanding the evolutionary biology of non-visual photosensory pathways and answer long-standing questions about the nature and distribution of photopigments in organisms, including providing a solution to the mystery of why nocturnal animals routinely have mutations that interrupt the function of their short wavelength sensitive photopigment gene.

Kuchenbecker, James A.; Neitz, Maureen

2012-01-01

142

Active dielectric antenna on chip for spatial light modulation.  

PubMed

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

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

2012-11-14

143

Active dielectric antenna on chip for spatial light modulation  

NASA Astrophysics Data System (ADS)

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

2012-11-01

144

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

145

Photocatalytic activities of various pentavalent bismuthates under visible light irradiation  

SciTech Connect

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

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

2011-08-15

146

Automatic planning of light source and camera placement for an active photometric stereo system  

Microsoft Academic Search

An automatic planning method of light source and camera placement for an active photometric stereo system is presented. Since photometric stereo systems normally use multiple light sources fixed to the environment, they cannot avoid shadows caused by surrounding objects. Using a movable light source and adapting its placement actively to the task environment eliminates shadows. Candidate positions for light source

Shigeyuki SAKANE; T. Sato

1991-01-01

147

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

148

A CMOS floating point multiplier  

NASA Astrophysics Data System (ADS)

This paper describes a 32-bit CMOS floating point multiplier. The chip can perform 32-bit floating point multiplication (based on the proposed IEEE Standard format) and 24-bit fixed point multiplication (two's complement format) in less than 78.7 and 71.1 ns, respectively, and the typical power dissipation is 195 mW at 10 million operations per second. High-speed multiplication techniques - a modified Booth's allgorithm, a carry save adder scheme, a high-speed CMOS full adder, and a modified carry select adder - are used to achieve the above high performance. The chip is designed for compatibility with 16-bit microcomputer systems, and is fabricated in 2 micron n-well CMOS technology; it contains about 23000 transistors of 5.75 x 5.67 sq mm in size.

Uya, M.; Kaneko, K.; Yasui, J.

1984-10-01

149

Pipeline riser for floating platforms  

SciTech Connect

An unarticulated riser pipe for connecting a subsea pipeline to facilities on a floating platform. The riser pipe has a vertical section which is rigidly attached to a horizontal section which provides flexibility. Means are provided to maintain the tension on the vertical section. In one embodiment, a subsea frame aids in connecting the horizontal and vertical sections and then to set a limit on permitted motion of the riser pipe.

Beynet, P.A.; Williams, E.K.

1981-09-22

150

Dragging a floating horizontal cylinder  

NASA Astrophysics Data System (ADS)

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

Lee, Duck-Gyu; Kim, Ho-Young

2010-11-01

151

Living crystals of light-activated colloidal surfers.  

PubMed

Spontaneous formation of colonies of bacteria or flocks of birds are examples of self-organization in active living matter. Here, we demonstrate a form of self-organization from nonequilibrium driving forces in a suspension of synthetic photoactivated colloidal particles. They lead to two-dimensional "living crystals," which form, break, explode, and re-form elsewhere. The dynamic assembly results from a competition between self-propulsion of particles and an attractive interaction induced respectively by osmotic and phoretic effects and activated by light. We measured a transition from normal to giant-number fluctuations. Our experiments are quantitatively described by simple numerical simulations. We show that the existence of the living crystals is intrinsically related to the out-of-equilibrium collisions of the self-propelled particles. PMID:23371555

Palacci, Jeremie; Sacanna, Stefano; Steinberg, Asher Preska; Pine, David J; Chaikin, Paul M

2013-01-31

152

Effect of light deprivation on binding activity of serotonin with light and heavy synaptosomes from various brain formations  

Microsoft Academic Search

The degree of binding of serotonin (5-HT) with light and heavy synaptosomes in various brain formations of control and visually deprived rabbits was studied by the writer's gel-filtration method. The activity of this process in heavy synaptosomes of control rabbits was equal in the visual cortex and superior colliculus and significantly higher than in the motor cortex. Light synaptosomes of

M. G. Uzbekov

1977-01-01

153

Effect of light deprivation on binding activity of serotonin with light and heavy synaptosomes from various brain formations  

Microsoft Academic Search

The degree of binding of serotonin (5-HT) with light and heavy synaptosomes in various brain formations of control and visually deprived rabbits was studied by the writer's gel-filtration method. The activity of this process in heavy synaptosomes of control rabbits was equal in the visual cortex and superior colliculus and significantly higher than in the motor cortex. Light synaptosomes of

M. G. Uzbekov

1980-01-01

154

Detection of eye blinks from EEG signals for home lighting system activation  

Microsoft Academic Search

The improvement in the development of lighting system has not considered eye blinking activity as a parameter to activate the system. In addition, the use of eye blink extracted from EEG signal has not been investigated. This study examines a suitable eye activity for activating home lighting system and then detects the occurrence of this activity from EEG signals. Two

M. S. bin Abd Rani; W. bt. Mansor

2009-01-01

155

Tctex2Related Outer Arm Dynein Light Chain Is Phosphorylated at Activation of Sperm Motility  

Microsoft Academic Search

When the motility of sperm is activated, only one light chain of flagellar outer arm dynein is phosphorylated in many organisms. We show here that the light chain to be phosphorylated was shown to be light chain 2 (LC2) in rainbow trout and chum salmon sperm and LC1 in sea urchin sperm. Molecular analyses of the phosphorylated light chains from

Kazuo Inaba; Osamu Kagami; Kazuo Ogawa

1999-01-01

156

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.

157

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.

158

Mechanism of activation of light-activated phosphodiesterase and evidence for homology with hormone-activated adenylate cyclase  

SciTech Connect

Light-activated cGMP phosphodiesterase (PDE) is one of the effector proteins in the rod outer segments in vertebrate retina. The hydrolysis of cGMP in rod occurs with a speed and light sensitivity which suggests a role for this hydrolysis in visual transduction. In fact, there is electrophysiological data which supports the possibility that cGMP could regulate rod membrane voltage. PDE shows very rapid activation in the presence of photons and GTP. We have called attention to the intriguing analogy between light activated rod phosphodiesterase and hormone activated adenylate cyclase. A number of studies have implicated the binding of GTP to a GTP binding protein as a factor in the hormone dependent activation of adenylate cyclase. Moreover, Cassel and Selinger have shown that hydrolysis of GTP is a component in the inactivation of the hormone dependent adenylate cyclase. We review here recent additional data which provide specific molecular details of the mechanism of light activation of rod PDE as well as demonstrate the exchange of components between light activated PDE and hormone activated cyclase.

Bitensky, M.W.; Yamazaki, A.; Wheeler, M.A.; George, J.S.; Rasenick, M.M.

1983-01-01

159

Genetics Home Reference: Floating-Harbor syndrome  

MedlinePLUS

... and Families Resources for Health Professionals What glossary definitions help with understanding Floating-Harbor syndrome? autosomal ; autosomal dominant ; brachydactyly ; cell ; clinodactyly ; cryptorchidism ; deficiency ; gene ; motor ; mutation ; ...

160

Floating platform well production apparatus  

SciTech Connect

A plurality of wells are clustered around a central riser which is maintained under tension from a floating platform. A plurality of spiders on the riser carry funnels in vertical alignment with the wells. The funnels are sufficiently large to permit the passage of wellhead connectors and master block valves, and the production risers include centralizers which brace the production riser from the funnels through a limited vertical range. Tensioning of the production riser is with a lower force and through a limited range which precludes disengagement of the centralizers from the funnel. Some centralizers are located to facilitate entry and attachment to the wellhead.

Nobileau, P.C.

1980-10-21

161

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

162

Automatic planning of light source placement for an active photometric stereo system  

Microsoft Academic Search

Presents an automatic planning method of light source placement for an active photometric stereo system. Since photometric stereo systems normally use multiple light sources fixed to the environment, they cannot avoid shadows caused by surrounding objects. One remedy for this situation is to use a movable light source and to adapt its placement actively to the task environment. Candidate positions

Shigeyuki SAKANE; Tomomasa SATO; Masayoshi KAKIKURA

1990-01-01

163

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

164

Light/dark modulation of enzyme activity in photosynthesis  

SciTech Connect

In photosynthetic species ranging from cyanobacteria to higher plants, many enzymes are light modulated. Most of the known light modulated enzymes are chloroplastic. Four mechanisms of modulation have been proposed. One function of light modulation is probably the autocatalytic build-up of reductive pentose phosphate cycle intermediates during the induction period of photosynthetic CO/sub 2/ fixation.

Anderson, L.E.; Ashton, A.R.; Mohamed, A.H.; Scheibe, R.

1982-02-01

165

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

Microsoft Academic Search

The antibacterial activity of photocatalytic titanium dioxide (TiO2) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO2

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

2006-01-01

166

Vertical penetration of floating ice sheets  

Microsoft Academic Search

Existing failure criteria for the bearing capacity of floating ice sheets predict the load for the occurrence of the first radial crack or a circumferential crack, when the maximum stress obtained from an elastic analysis in the ice equals the tensile strength. From full-scale and small-scale tests, the ultimate load to cause complete penetration of a floating ice sheet is

Devinder S. Sodhi

1998-01-01

167

Sinking Float-Operated Irrigation Gate.  

National Technical Information Service (NTIS)

The automatic check gate stops the flow of water in an irrigation ditch after the lapse of a predetermined time. A float is mounted to the gate and provided with a valve for admitting water at a controlled rate whereby the float loses its buoyancy and sin...

A. S. Humpherys

1965-01-01

168

Hydroelastic analysis of a large floating structure  

Microsoft Academic Search

An analytical approach to predict the bending vibration of a very large floating structure of thin and elongated rectangular plate configuration, floating on water of shallow depth and under the action of a monochromatic head wave, is presented. The horizontal size of the plate is huge compared with the wavelength of the incident waves, yet the wavelength is much larger

M. Ohkusu; Y. Namba

2004-01-01

169

Variable-correction truncated floating point multipliers  

Microsoft Academic Search

About half the hardware for floating point multipliers is needed only to guarantee correctly rounded results. For multimedia, graphics, and DSP systems, a significant reduction in area, delay, and power can be achieved by producing results that are not correctly rounded. This paper presents an efficient method for designing variable-correction truncated floating point multipliers that produce results with a maximum

Kent E. Wires; Michael J. Schulte; James E. Stine

2000-01-01

170

How to read floating point numbers accurately  

Microsoft Academic Search

Converting decimal scientific notation into binary floating point is nontrivial, but this conversion can be performed with the best possible accuracy without sacrificing efficiency.Consider the problem of converting decimal scientific notation for a number into the best binary floating point approximation to that number, for some fixed precision. This problem cannot be solved using arithmetic of any fixed precision. Hence

William D. Clinger

2004-01-01

171

How to read floating point numbers accurately  

Microsoft Academic Search

Consider the problem of converting decimal scientific notation for a number into the best binary floating point approximation to that number, for some fixed precision. This problem cannot be solved using arithmetic of any fixed precision. Hence the IEEE Standard for Binary Floating-Point Arithmetic does not require the result of such a conversion to be the best approximation.This paper presents

William D. Clinger

1990-01-01

172

Light  

Microsoft Academic Search

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

M. I. Sobel

1989-01-01

173

Light perception in plants: cytokinins and red light join forces to keep phytochrome B active  

Microsoft Academic Search

Plant growth and development is modulated by internal cues such as the hormonal balance and external factors. Plants are particularly sensitive to their light environment, which they scrutinize with at least three classes of photoreceptors. In recent years, it has become increasingly clear that light and hormonal signaling interact at several levels. A cytokinin receptor was recently identified together with

Christian Fankhauser

2002-01-01

174

Rapid light curves: A powerful tool to assess photosynthetic activity  

Microsoft Academic Search

Rapid light curves provide detailed information on the saturation characteristics of electron transport, as well as the overall photosynthetic performance of a plant. Rapid light curves were collected from samples of Zostera marina grown under low and high-light conditions (50 and 300?molphotonsm?2s?1) and the distinctive patterns of RLC parameters are discussed, in terms of differential sink capacity and PSII reaction

Peter J. Ralph; Rolf Gademann

2005-01-01

175

El Hierro's floating stones as messengers of crust-magma interaction at depth  

NASA Astrophysics Data System (ADS)

During the early stages of the submarine eruption that started on October 10 2011 south of El Hierro, Canary Islands, Spain, peculiar eruption products were found floating on the sea surface. These centimetre- to decimetre-sized "bombs" have been termed "restingolites" after the nearby village La Restinga and consist of a basaltic rind and a white to light grey core that resembles pumice in texture. According to Troll et al. (2011; see also Troll et al. EGU 2012 Abstracts), this material consists of a glassy matrix hosting extensive vesicle networks, which results in extremely low densities allowing these rocks to float on sea water. Mineralogical and geochemical analyses reveal that the "restingolites" originate from the sedimentary rocks (sand-, silt-, and mudstones) that form layer 1 of the oceanic crust beneath El Hierro. During the onset and early stages of the eruption, magma ponded at the base of this sedimentary sequence, breaking its way through the sedimentary rocks to the ocean floor. The textures of the "restingolites" reveal that crust-magma interaction during fragmentation and transport of the xenoliths involved rapid partial melting and volatile exsolution. Xenoliths strikingly similar to those from El Hierro are known from eruptions on other Canary Islands (e.g. La Palma, Gran Canaria, and Lanzarote). In fact, they resemble in texture xenoliths of various protoliths from volcanic areas worldwide (e.g. Krakatao, Indonesia, Cerro Quemado, Guatemala, Laacher See, Germany). This indicates that the process of partial melting and volatile exsolution, which the "restingolites" bear witness of, is probably occurring frequently during shallow crustal magma emplacement. Thermomechanical numerical models of the effect of the density decrease associated with the formation of vesicle networks in partially molten xenoliths show that xenoliths of crustal rocks initially sink in a magma chamber, but may start to float to the chamber roof once they start to heat up and vesiculate. The "floating stones" from El Hierro thus represent the products of crust-magma interaction beneath the Canary Islands, but is probably relevant in most volcanic areas and tectonic settings. In addition, xenolith devolatilisation has important general implications for the mechanics of crustal recycling, magma emplacement into the upper crust and volatile release from active volcanic systems.

Burchardt, S.; Troll, V. R.; Schmeling, H.; Koyi, H.; Blythe, L. S.; Longpré, M. A.; Deegan, F. M.

2012-04-01

176

Characterization and modeling of light activated shape memory polymer  

NASA Astrophysics Data System (ADS)

Shape memory polymers have recently become the focus of research for their unique ability to switch between two modulus states, allowing them to both recover from large amounts of strain as well as support complex loads. Part of this research involves engineering new formulas specifically designed for applications where traditional thermally activated SMPs are not ideal by tailoring the activation method used to transition the polymer. One such class of polymers is those that utilize optical energy at specific wavelengths to create and cleave crosslinks. It is the development of this new class of light activated shape memory polymers (LASMP) that is the focus of the presented work. Experimental methods are newly created for this novel class of active materials. Several candidate LASMP formulas are then subjected to this set of experiments characterizing their mechanical and optical properties. Experimentally observed variations among the formulae include virgin state modulus, percent change in modulus with stimulus, and in some instances inelastic response. To expedite the development of LASMP, a first principles multi-scale model based on the polymer's molecular structure is presented and used to predict the stress response of the candidate formulas. Rotational isomeric state (RIS) theory is used to build a molecular model of a phantom polymer chain. Assessment of the resulting conformation is then made via the Johnson family of statistical distributions and Boltzmann statistical thermodynamics. The ability of the presented model to predict material properties based on the molecular structure of the polymer reduces the time and resources required to test new candidate formulas of LASMP as well as aiding in the ability to tailor the polymer to specific application requirements. While the first principles model works well to identify promising formulas, it lacks precision. The stress contribution from the constraints on the polymer chain's junctions and neighboring chain entanglements is then added to that of the phantom network allowing Young's modulus to be calculated from the predicted stress response of the polymer. Simple extension, equi-biaxial, and shear strain states are modeled and associated predicted material properties presented. The added precision of this phenomenological extension will aid device design.

Beblo, Richard Vincent

177

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

178

Color-Encoded Structured Light for Rapid Active Ranging  

Microsoft Academic Search

In this paper, we discuss a novel strategy for rapid acquisition of the range map of a scene employing color-encoded structured light. This technique offers several potential advantages including increased speed and improved accuracy. In this approach we illuminate the scene with a single encoded grid of colored light stripes. The indexing problem, that of matching a detected image plane

Kim L. Boyer; Avinash C. Kak

1987-01-01

179

Planet signatures in collisionally active debris discs: scattered light images  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

180

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

181

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

2013-08-13

182

Judging disease activity in rheumatoid arthritis by serum free kappa and lambda light chain levels.  

PubMed

The study aimed to evaluate the levels of serum free kappa (?) and lambda (?) light chains in patients with rheumatoid arthritis (RA) as well as exploring the association between serum free ? and ? light chains and activity of RA. For this purpose, healthy individuals and patients with active RA and RA in remission were enrolled, and their serum levels of free ? and ? light chains were measured using rate nephelometry. The diagnostic accuracy of serum free ? and ? light chains was evaluated by receiver operating characteristic curves and 95% confidence intervals for areas under the curve (AUC). The results obtained indicated that the levels of serum free ? and ? light chains in patients with active RA were significantly higher than those of patients in remission and of healthy controls (p < 0.05). Further, the AUC values in patients with active RA were 0.871 for free ? light chain and 0.781 for free ? light chain. When the optimal cut-off point for serum ? light chain was 8.02 g/L, the maximum sensitivity and specificity were 82.5% and 82.5%, respectively, and when the optimal cut-off point for serum ? light chain was 3.57 g/L, the maximum sensitivity and specificity were 80% and 82.5%, respectively. It was thus found that serum levels of free ? and ? light chains were positively correlated with disease activity in RA, the Disease Activity Score 28 (DAS28), and values for C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), platelet count (PLT), rheumatoid factor (RF), and anticitrullinated protein antibody (ACPA) (p < 0.05). In conclusion, high serum levels of free ? and ? light chains in patients with active RA are closely correlated with disease activity parameters including DAS28, CRP, ESR, PLT, RF, and ACPA. Thus, the above-mentioned levels of serum free ? and ? light chains may be used as important indicators of activity of RA. PMID:24099109

Ye, Yun; Li, Su-Liang; Xie, Ming; Jiang, Ping; Liu, Kai-Ge; Li, Ya-Jun

2013-06-14

183

Light activation of the sodium pump in blowfly photoreceptors  

Microsoft Academic Search

1.The oxygen consumption of the compound eye in the blowfly was determined during light exposure and in darkness by a manometric measuring technique. Within the first 10 s of exposure to bright white light the oxygen uptake increased up to 20 × the resting value in darkness, which is 2.4 to 3×10-5ml oxygen x min-1 × eye-1.2.The time course of

Kurt Hamdorf; Peter Hochstrate; Gunnar Höglund; Brigitte Burbach; Ursula Wiegand

1988-01-01

184

FloatNet: An Intelligent Environment for Tobacco Transplants Production  

Microsoft Academic Search

A web environment has been designed for managing float system tobacco transplants cultivation. The environment is called FloatNET and includes an integrated interface supports Tobacco transplants cultivation. The float system is located in a greenhouse and consists of floor beds - so called 'wet beds' - were filled with nutrient solution. Transplants are developed on float Styrofoam trays filled with

Aglaia Liopa-Tsakalidis; Pantelis Barouchas; Athanasios Koulopoulos; Evangelos Sakkopoulos; Giannis Tzimas; Leonidas Panagiotopoulos

185

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Main float buoyancy. 25.751 Section 25.751 Aeronautics...Floats and Hulls § 25.751 Main float buoyancy. Each main float must haveâ (a) A buoyancy of 80 percent in excess of that...

2009-01-01

186

14 CFR 27.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

187

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

188

14 CFR 25.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

189

14 CFR 29.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

190

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 false Main float buoyancy. 23.751 Section 23.751 Aeronautics...Floats and Hulls § 23.751 Main float buoyancy. (a) Each main float must haveâ (1) A buoyancy of 80 percent in excess of the...

2009-01-01

191

14 CFR 27.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 2009-01-01 false Main float buoyancy. 27.751 Section 27.751 Aeronautics...Floats and Hulls § 27.751 Main float buoyancy. (a) For main floats, the buoyancy necessary to support the maximum weight...

2009-01-01

192

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2010 CFR

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

2010-01-01

193

14 CFR 23.751 - Main float buoyancy.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

194

Technical and economic aspects of a floating offshore wind farm  

Microsoft Academic Search

Development of the conceptual design for FLOAT – an offshore floating wind turbine – is described in this paper. This design represents a marriage of the wind power and offshore oil and gas technology. The objective of the FLOAT project is to develop a floating wind turbine system enabling the economic generation of electricity from wind power in offshore locations,

K. C Tong

1998-01-01

195

Characterization of spiral inductors with patterned floating structures  

Microsoft Academic Search

The impact of two different types of floating patterns on spiral inductors was investigated. Both patterned trench isolation with a floating p\\/n junction and floating metal poles were implemented underneath reference spiral inductors. All three types of inductors have an identical spiral geometry. Combination of patterned trench isolation with a floating p\\/n junction increases maximum quality factor (Qmax) by 17%

Chiaming Alex Chang; Sung-Pi Tseng; Jun Yi Chuang; Shiue-Shr Jiang; J. Andrew Yeh

2004-01-01

196

A novel hydrogen-evolving photocatalyst InVO 4 active under visible light irradiation  

Microsoft Academic Search

InVO4, with band gap of about 2.0 eV, was found to be a new visible light responding photocatalyst for water decomposition. The photocatalyst showed activity to visible light in a wide wavelength range up to 600 nm. Although the native photocatalyst could evolve H2 from pure water under visible light irradiation (?>420nm), the photocatalytic activity increases significantly by loading NiO

Jinhua Ye; Zhigang Zou; Mitsutake Oshikiri; Akiyuki Matsushita; Masahiko Shimoda; Motoharu Imai; Toetsu Shishido

2002-01-01

197

Light Treatment for Sleep Disorders: Consensus ReportIII. Alerting and Activating Effects  

Microsoft Academic Search

In addition to the well-established phase-shifting properties of timed exposure to bright light, some investigators have reported an acute alerting, or activating, effect of bright light exposure. To the extent that bright light interventions for sleep disturbance may cause subjective and\\/or central nervous system activation, such a property may adversely affect the efficacy of treatment. Data obtained from patient samples

Scott S. Campbell; Derk-Jan Dijk; Ziad Boulos; Charmane I. Eastman; Alfred J. Lewy; Michael Terman

1995-01-01

198

Seeing the Moon: A Series of Inquiry Activities Using Light to Investigate the Moon  

Microsoft Academic Search

Seeing the Moon: Using Light to Investigate the Moon is a series of educational activity modules created for the Moon Mineralogy Mapper instrument aboard the Chandrayaan-1. In these modules, classroom students investigate light and the geologic history of the Moon. Through the hands-on inquiry based activities, 5th to 8th grade students experiment with light and color, collect and analyze authentic

Christine Shupla; C. Runyon; S. Shipp; A. H. Tremain

2007-01-01

199

Light-inducible activation of target mRNA translation in mammalian cells.  

PubMed

A genetically encoded optogenetic system was constructed that activates mRNA translation in mammalian cells in response to light. Blue light induces the reconstitution of an RNA binding domain and a translation initiation domain, thereby activating target mRNA translation downstream of the binding sites. PMID:23925486

Cao, Jicong; Arha, Manish; Sudrik, Chaitanya; Bugaj, Lukasz J; Schaffer, David V; Kane, Ravi S

2013-08-22

200

Understanding and Improving Sorbents for Floating Oil.  

National Technical Information Service (NTIS)

Acquisition of floating oil by sorbents involves a balance between internal permeation processes and external phenomena occurring in the oil pool. As a basis for improving sorbents and sorbent systems, this program considers internal and external processe...

L. D. Nichols

1974-01-01

201

Prototype Performance Characteristics of a Floating Breakwater.  

National Technical Information Service (NTIS)

The characteristics, i.e., transmission coefficients, anchor forces, and accelerations in heave, roll, and sway are evaluated from measurements taken on a floating breakwater protecting a small boat harbor at Tenakee Springs, AL. The breakwater consists o...

D. R. Christensen E. P. Rickey

1974-01-01

202

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

203

PLM Floating-Point Interface Program.  

National Technical Information Service (NTIS)

A major failing of Intel's PLM language is its inability to handle scientific notation (floating-point) calculations. An interface program that allows PLM to perform such calculations is described. A comparison of this modified PLM with an assembly langua...

C. Paoni M. Maples

1976-01-01

204

Floating patterns of metered dose inhalers.  

PubMed

As long as metered dose inhalers have existed, patients have sought a reliable method to determine if a given canister was still potent. Concerning beta agonists, the answer to this question may be lifesaving. Issues of compliance have made dating canisters or counting doses impractical. Likewise, previous claims of floating characteristics are unreliable. In tap water, we float-tested 13 commonly used inhalers three times each, observing variations as they were incrementally actuated, emptying their contents. One essential pattern was observed. Almost all prescription-size canisters sink when full; all float by the time one-third of their contents is gone. Orientation of prescription-size canisters changes in a distinct pattern especially near 90% depletion. Sample-size canisters showed some variance. Results suggest that the pharmaceutical industry should include individual floating characteristics as part of the package insert as they provide a reproducible means of gauging contents. PMID:9350161

Wolf, B L; Cochran, K R

1997-01-01

205

Instability of Thermocapillary Convection in Floating Zones.  

National Technical Information Service (NTIS)

Bifurcation theory combined with the finite difference method is applied to investigate the instability of thermocapillary convection in a model of the floating zone crystal growth process. Both axisymmetric (n = 0) and nonaxisymmetric (n greater than or ...

G. Chen B. Roux

1992-01-01

206

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

207

Reduced activity of plastid protoporphyrinogen oxidase causes attenuated photodynamic damage during high-light compared to low-light exposure.  

PubMed

Protoporphyrinogen oxidase (EC 1.3.3.4, PPOX) is the last enzyme in the branched tetrapyrrole biosynthetic pathway, before its substrate protoporphyrin is directed to the Mg and Fe branches for chlorophyll and haem biosynthesis, respectively. The enzyme exists in many plants in two similar isoforms, which are either exclusively located in plastids (PPOX I) or in mitochondria and plastids (PPOX II). Antisense RNA expression inhibited the formation of PPOX I in transgenic tobacco plants, which showed reduced growth rate and necrotic leaf damage. The cytotoxic effect is attributed to accumulation of photodynamically acting protoporphyrin. The expression levels of PPOX I mRNA and protein and the cellular enzyme activities were reduced to similar extents in transgenic plants grown under low- or high-light conditions (70 and 530 mumol photons m(-2) sec(-1)). More necrotic leaf lesions were surprisingly generated under low- than under high-light exposure. Several reasons were explored to explain this paradox and the intriguing necrotic phenotype of PPOX-deficient plants under both light intensity growth conditions. The same reduction of PPOX expression and activity under both light conditions led to similar initial protoporphyrin, but to faster decrease in protoporphyrin content during high light. It is likely that a light intensity-dependent degradation of reduced and oxidized porphyrins prevents severe photodynamic leaf damage. Moreover, under high-light conditions, elevated contents of reduced and total low-molecular-weight antioxidants contribute to the protection against photosensitizing porphyrins. These reducing conditions stabilize protoporphyrinogen in plastids and allow their redirection into the metabolic pathway. PMID:17059408

Lermontova, Inna; Grimm, Bernhard

2006-10-19

208

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

209

Gas transfer in floating-leaved plants  

Microsoft Academic Search

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

W. Große; C. Bauch

1991-01-01

210

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

211

Studies of Marangoni convection in floating zones  

Microsoft Academic Search

Marangoni convection (MC) has been studied in a NaNO3-floating zone by flow visualization and temperature measurements under 1-g and under 0.4 g (sounding rocket TEXUS IIIa). The effects of surface tension forces and buoyant forces have been separated by suppression of MC with a surface contamination. MC is the dominating flow in small volumes. Time dependent MC in floating zones

D. Schwabe; A. Scharmann; F. Preisser

1982-01-01

212

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

213

Nanoflare Properties throughout Active Regions: Comparing SDO/AIA Observations with Modeled Active Region Light Curves  

NASA Astrophysics Data System (ADS)

Coronal plasma in active regions is typically measured to be at temperatures near 1-3 MK. Is the majority of the coronal plasma in hydrostatic equilibrium, maintained at these temperatures through a form of quasi-steady heating, or is this simply a measure of the average temperature of widely varying, impulsively heated coronal plasma? Addressing this question is complicated by the fact that the corona is optically thin: many thousands of flux tubes which are heated completely independently are contributing to the total emission along a given line of sight. There is a large body of work focused on the heating of isolated features - coronal loops - which are impulsively heated, however it is the diffuse emission between loops which often comprises the majority of active region emission. Therefore in this study we move beyond isolated features and analyze all of the emission in an entire active region from all contributing flux tubes. We investigate light curves systematically using SDO/AIA observations. We also model the active region corona as a line-of-sight integration of many thousands of completely independently heated flux tubes. The emission from these flux tubes may be time dependent, quasi-steady, or a mix of both, depending on the cadence of heat release. We demonstrate that despite the superposition of randomly heated flux tubes, different distributions of nanoflare cadences produce distinct signatures in light curves observed with multi-wavelength and high time cadence data, such as those from SDO/AIA. We conclude that the majority of the active region plasma is not maintained in hydrostatic equilibrium, rather it is undergoing dynamic heating and cooling cycles. The observed emission is consistent with heating through impulsive nanoflares, whose energy is a function of location within the active region. This research was supported by an appointment to the NASA Postdoctoral Program at GSFC/NASA.

Viall, Nicholeen; Klimchuk, J.

2012-05-01

214

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

215

Light intensity limits foraging activity in nocturnal and crepuscular bees  

Microsoft Academic Search

A crepuscular or nocturnal lifestyle has evolved in bees several times independently, probably to explore rewarding pollen sources without competition and to minimize predation and nest parasites. Despite these obvious advantages, only few bee species are nocturnal. Here we show that the sensitivity of the bee apposition eye is a major factor limiting the ability to forage in dim light.

Almut Kelber; Eric J. Warrant; Michael Pfaff; Rita Wallen; Jamie C. Theobald; William T. Wcislo

2005-01-01

216

Experimental studies of light propagation in active scattering media  

Microsoft Academic Search

Over the past several years there has been a great deal of renewed interest in multiple scattering systems with gain. Laser action has been demonstrated in systems containing high gain laser dyes mixed with passive scattering particles. In these materials, known as photonic paint, the scatterers redirect the light and provide the feedback mechanism to initiate lasing. A method of

Amy Elizabeth Perkins

1998-01-01

217

Light intensity limits foraging activity in nocturnal and crepuscular bees  

Microsoft Academic Search

A crepuscular or nocturnal lifestyle has evolved in bees several times independently, probably to explore rewarding pollen sources without competition and to minimize predation and nest parasites. Despite these obvious advantages, only few bee species are nocturnal. Here we show that the sensitivity of the bee apposition eye is a major factor limiting the ability to forage in dim light.

Almut Kelber; Eric J. Warrant; Michael Pfaff; Rita Wallén; Jamie C. Theobald; William T. Wcislo; Robert A. Raguso

2006-01-01

218

Structured-light stereo: Comparative analysis and integration of structured-light and active stereo for measuring dynamic shape  

NASA Astrophysics Data System (ADS)

In computer vision, two major active range imaging methods have been frequently employed for rapid and efficient shape recovery: (a) conventional active stereo vision and (b) conventional structured-light vision. This paper presents a comparative analysis and an integration of the two active approaches, namely, a structured-light stereo approach for the acquisition of dynamic shape. We first investigate the strengths and weaknesses of the two approaches in terms of accuracy, computational cost, field of view, depth of field, and color sensitivity. Based on this analysis, we propose a novel integrated method, the structured-light stereo, to recover dynamic shapes from a wider view with less occlusion by taking most of the benefits of the two approaches. The main idea is as follows. We first build a system composed of two cameras and a single projector (just a basic setup for conventional active stereo), and the projector projects a single "one-shot" color-stripe pattern. The next step is to estimate reliable correspondences between each camera and the projector via an accurate and efficient pattern decoding technique, and some remaining unresolved regions are explored by a stereo matching technique, which is less sensitive to object surface colors and defocus due to the projector's short depth of field, to estimate additional correspondences. We demonstrate the efficacy of the integrated method through experimental results.

Jang, Wonkwi; Je, Changsoo; Seo, Yongduek; Lee, Sang Wook

2013-11-01

219

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

220

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

221

Two independent light signals cooperate in the activation of the plastid psbD blue light-responsive promoter in Arabidopsis.  

PubMed

The psbD blue light-responsive promoter (BLRP), whose activation has been considered to require strong blue light, is recognized only by SIG5 among six sigma factors of plastid RNA polymerase in Arabidopsis. We found SIG5 transcript accumulation was rapidly induced after a 30-min induction time by blue light (470 nm) with an intensity threshold of 5 micromol m(-2)s(-1) through cryptochromes. Besides this weak blue light, the psbD BLRP activation required the stronger light such as 50 micromol m(-2)s(-1) irrespective of blue or red light (660 nm). Thus, the two independent light signalings, the cryptochrome-mediated signaling to induce SIG5 transcription and the stronger light-dependent signaling, cooperate to activate the psbD BLRP. PMID:15280012

Mochizuki, Takateru; Onda, Yayoi; Fujiwara, Emi; Wada, Masamitsu; Toyoshima, Yoshinori

2004-07-30

222

A Variable Light Domain Fluorogen Activating Protein Homodimerizes To Activate Dimethylindole Red  

SciTech Connect

Novel fluorescent tools such as green fluorescent protein analogues and fluorogen activating proteins (FAPs) are useful in biological imaging for tracking protein dynamics in real time with a low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (V{sub H}) and variable light (V{sub L}) domains covalently attached via a glycine- and serine-rich linker. Previously, we determined that the yeast surface clone, V{sub H}-V{sub L} M8, could bind and activate the fluorogen dimethylindole red (DIR) but that the fluorogen activation properties were localized to the M8V{sub L} domain. We report here that both nuclear magnetic resonance and X-ray diffraction methods indicate the M8V{sub L} forms noncovalent, antiparallel homodimers that are the fluorogen activating species. The M8V{sub L} homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments with both V{sub H}-V{sub L} M8 and M8V{sub L}, led us to rationally design tandem, covalent homodimers of M8V{sub L} domains joined by a flexible linker that have a high affinity for DIR and good quantum yields.

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

2012-07-11

223

A variable light domain fluorogen activating protein homodimerizes to activate dimethylindole red.  

PubMed

Novel fluorescent tools such as green fluorescent protein analogues and fluorogen activating proteins (FAPs) are useful in biological imaging for tracking protein dynamics in real time with a low fluorescence background. FAPs are single-chain variable fragments (scFvs) selected from a yeast surface display library that produce fluorescence upon binding a specific dye or fluorogen that is normally not fluorescent when present in solution. FAPs generally consist of human immunoglobulin variable heavy (V(H)) and variable light (V(L)) domains covalently attached via a glycine- and serine-rich linker. Previously, we determined that the yeast surface clone, V(H)-V(L) M8, could bind and activate the fluorogen dimethylindole red (DIR) but that the fluorogen activation properties were localized to the M8V(L) domain. We report here that both nuclear magnetic resonance and X-ray diffraction methods indicate the M8V(L) forms noncovalent, antiparallel homodimers that are the fluorogen activating species. The M8V(L) homodimers activate DIR by restriction of internal rotation of the bound dye. These structural results, together with directed evolution experiments with both V(H)-V(L) M8 and M8V(L), led us to rationally design tandem, covalent homodimers of M8V(L) domains joined by a flexible linker that have a high affinity for DIR and good quantum yields. PMID:22390683

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

2012-03-14

224

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

225

Floating Zone Growth and Scintillation Characteristics of Cerium-Doped Gadolinium Pyrosilicate Single Crystals  

Microsoft Academic Search

Growth of cerium-doped gadolinium pyrosilicate single crystals, which show 2.5 times greater light output for gamma-rays and five times greater light output for alpha-particles than GSO single crystals, is accomplished using the floating zone growth method (FZ method). Although growth of (GPS) single crystal is considered to be difficult because it melts incongruently according to the phase diagram of system,

S. Kawamura; J. H. Kaneko; M. Higuchi; T. Yamaguchi; J. Haruna; Y. Yagi; K. Susa; F. Fujita; A. Homma; S. Nishiyama; K. Kurashige; H. Ishibashi; M. Furusaka

2007-01-01

226

Human and Drosophila Cryptochromes Are Light Activated by Flavin Photoreduction in Living Cells  

Microsoft Academic Search

Cryptochromes are a class of flavoprotein blue-light signaling receptors found in plants, animals, and humans that control plant development and the entrainment of circadian rhythms. In plant cryptochromes, light activation is proposed to result from photoreduction of a protein-bound flavin chromophore through intramolecular electron transfer. However, although similar in structure to plant cryptochromes, the light-response mechanism of animal cryptochromes remains

Nathalie Hoang; Erik Schleicher; Sylwia Kacprzak; Jean-Pierre Bouly; Marie Picot; William Wu; Albrecht Berndt; Eva Wolf; Robert Bittl; Margaret Ahmad

2008-01-01

227

Light Activation as a Method of Regulating and Studying Gene Expression  

PubMed Central

SUMMARY OF RECENT ADVANCES Recently, several advances have been made in the activation and deactivation of gene expression using light. These developments are based on the application of small molecule inducers of gene expression, antisense- or RNA interference-mediated gene silencing, and the photochemical control of proteins regulating gene function. The majority of the examples employ a classical “caging technology”, through the chemical installation of a light-removable protecting group on the biological molecule (small molecule, oligonucleotide, or protein) of interest and rendering it inactive. UV light irradiation then removes the caging group and activates the molecule, enabling control over gene activity with high spatial and temporal resolution.

Deiters, Alexander

2009-01-01

228

Preparation of S-doped TiO 2 photocatalysts and their photocatalytic activities under visible light  

Microsoft Academic Search

Although titanium dioxide photocatalysts having anatase phase are a promising substrate for photodegradation of pollutants in water and air, their photocatalytic activities show only under ultraviolet (UV) light. For us to utilized a wide range of incident light such as solar light, development of the photocatalysts whose activities show under visible light is one of the most important strategies. We

Teruhisa Ohno; Miyako Akiyoshi; Tsutomu Umebayashi; Keisuke Asai; Takahiro Mitsui; Michio Matsumura

2004-01-01

229

Battery charging in float vs. cycling environments  

SciTech Connect

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

COREY,GARTH P.

2000-04-20

230

On characterizing the variability properties of X-ray light curves from active galaxies  

Microsoft Academic Search

We review some practical aspects of measuring the amplitude of variability in `red noise' light curves typical of those from active galactic nuclei (AGN). The quantities commonly used to estimate the variability amplitude in AGN light curves, such as the fractional rms variability amplitude, Fvar, and excess variance, sigma2XS, are examined. Their statistical properties, relationship to the power spectrum and

S. Vaughan; R. Edelson; R. S. Warwick; P. Uttley

2003-01-01

231

Contact effects in light activated GaAs switches  

NASA Astrophysics Data System (ADS)

The purpose of this work was to examine the effects of various types of contacts on the switching behavior of a light-triggered power switch. The switch was constructed from a homogeneous wafer of chromium-doped gallium arsenide; the contacts were either ohmic, non-ohmic, or Schottky barriers. These were formed on the wafer in two geometries; both contacts on one side, and one contact spacings were used to permit the effects of the location of the existing laser pulse to be studied. A high voltage power supply (zero to 20 kV) was employed as the bias supply. A Nd:YAG laser, in the pulsed mode, was used to trigger the switch, which was mounted on a cold finger cooled to near liquid nitrogen temperature. Cooling reduced the dark current to manageable values (less than 1 micro A), and also reduced the avalanche breakdown voltage. The results of the measurements indicate that ohmic contacts produced more reliable switching than the non-ohmic or Schottky contacts, in as much as the shape of the output current pulse was better, and the number of pulses which the switches could sustain before the pulse shape deteriorated was greater, for the ohmic contacts. Surface discharge between the one-sided contacts obscured any differences in switching characteristics which might have depended on the location of the pulsed light excitation, so that no correlation between position and behavior could be obtained.

Durkin, P. S.

1985-05-01

232

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...

233

75 FR 52326 - Agency Information Collection Activities; Proposed Collection; Comment Request; EPA's Light-Duty...  

Federal Register 2010, 2011, 2012, 2013

...ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OAR-2010-0690; FRL-9192-9; EPA ICR No. 0222.09; OMB Control No. 2060-0086...Activities; Proposed Collection; Comment Request; EPA's Light-Duty In-Use Vehicle Testing...

2010-08-25

234

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

235

Blow-off float vehicle recovery apparatus  

US Patent & Trademark Office Database

The invention in one variation is a modular recovery apparatus for dispensing a tether spool having a tow line with a float, where the tow line can be used to retrieve an unmanned underwater vehicle and other underwater platforms. The modular recovery apparatus can be triggered underwater or on the surface, and being modular in configuration it is suitable to be fitted to a variety of unmanned underwater vehicles (UUVs). The apparatus has a tether spool that is spring loaded, such that when the tether spool is deployed, the spring expels the tether spool with sufficient force to clearly separate it from the UUV. One end of the tow line is typically fastened to a tow point on the UUV, and an opposing end is attached to the float. When the tether spool is deployed, the tow line unwinds from the float, providing a securable length.

Gibson; Robert (Panama City, FL); Hollis; Walt (Panama City, FL); Leasko; Robert A. (Panama City, FL)

2012-05-01

236

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

237

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

ERIC Educational Resources Information Center

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

DeBruin, Jerry

238

Visible light photocatalytic activity in nitrogen-doped TiO{sub 2} nanobelts  

SciTech Connect

We present a comprehensive experimental and theoretical study of the electronic properties and photocatalytic activity of nitrogen-doped anatase TiO{sub 2} nanobelts. UV-visible spectra show enhanced absorption in the visible light range for nitrogen-doped nanobelts compared to the pristine sample. The nitrogen-doped nanobelts exhibit improved photocatalytic activity compared to the pristine sample upon visible light irradiation. Furthermore, the incorporation of nitrogen introduces localized states in the band gap.

De Nyago Tafen; Lewis, James P. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506 (United States); Wang Jin; Wu Nianqiang [Department of Mechanical and Aerospace Engineering, West Virginia University, Morgantown, West Virginia 26506 (United States)

2009-03-02

239

An improved active imaging method for upgrading low-light-level image detection sensitivity  

NASA Astrophysics Data System (ADS)

Active imaging is an essential tool for low-light-level imaging. However, it has some drawbacks, such as limited imaging range and lack of security. We optimize the imaging approach by casting a saw-tooth wave auxiliary light signal over the sensor. Here, the auxiliary signal is superposed with a low-light-level signal, which is too weak to be measured by the sensor. After acquiring a superimposed image set in one saw-tooth wave circle, low-light-level image estimation is achieved by implementing least-square algorithm during data processing. This improved method not only makes active imaging overcome the drawbacks mentioned above, but also provides a feasible way to improve the low-light-level image detection sensitivity.

Tang, Hongying

2013-09-01

240

Influence of light activation on the volumetric change of core foundation resins.  

PubMed

A core foundation system is frequently used in endodontically treated teeth that suffer excessive loss of the coronal portion of their structure. The volumetric shrinkage of core foundation resins may create marginal gaps that influence the bonding ability and longevity of a restored tooth. Little is known about how activation conditions of resin core foundation resin pastes affect their volumetric shrinkage. This study evaluated the influence of light intensity and light activation duration on volumetric shrinkage of direct core foundation resins. Two dual- and one light-activated core foundation resin pastes were employed. The material was placed in a Teflon mold 4 mm in diameter and 2 mm in height and extruded into a water filled dilatometer. The specimens were then light activated and the change in height of the meniscus of water was recorded using a charged-coupled device camera. The average volumetric shrinkage of the core foundation resins after 180 seconds ranged from 1.53% to 2.63%. For all materials tested, there was a tendency for increased volumetric shrinkage with increased light activation time and intensity. The results of this study indicate that the volumetric change of core foundation resins is influenced by the time and intensity of light activation. PMID:16268400

Uekusa, Satoshi; Miyazaki, Masashi; Rikuta, Akitomo; Kurokawa, Hiroyasu; Moore, B Keith

241

Red light-green light: Using a Model-Eliciting Activity in a logic design course  

Microsoft Academic Search

This paper outlines the use of a Model-Eliciting Activity (MEA) in a logic design course that introduces students to design through an authentic client-driven problem. The MEA involved creating a model of a traffic signal controller for an intersection of a U.S. highway and a county road near the university. Students were given background information on traffic signal controllers and

Eric W. Johnson; Tamara J. Moore

2010-01-01

242

Light evokes melanopsin-dependent vocalization and neural activation associated with aversive experience in neonatal mice.  

PubMed

Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are the only functional photoreceptive cells in the eye of newborn mice. Through postnatal day 9, in the absence of functional rods and cones, these ipRGCs mediate a robust avoidance behavior to a light source, termed negative phototaxis. To determine whether this behavior is associated with an aversive experience in neonatal mice, we characterized light-induced vocalizations and patterns of neuronal activation in regions of the brain involved in the processing of aversive and painful stimuli. Light evoked distinct melanopsin-dependent ultrasonic vocalizations identical to those emitted under stressful conditions, such as isolation from the litter. In contrast, light did not evoke the broad-spectrum calls elicited by acute mechanical pain. Using markers of neuronal activation, we found that light induced the immediate-early gene product Fos in the posterior thalamus, a brain region associated with the enhancement of responses to mechanical stimulation of the dura by light, and thought to be the basis for migrainous photophobia. Additionally, light induced the phosphorylation of extracellular-related kinase (pERK) in neurons of the central amygdala, an intracellular signal associated with the processing of the aversive aspects of pain. However, light did not activate Fos expression in the spinal trigeminal nucleus caudalis, the primary receptive field for painful stimulation to the head. We conclude that these light-evoked vocalizations and the distinct pattern of brain activation in neonatal mice are consistent with a melanopsin-dependent neural pathway involved in processing light as an aversive but not acutely painful stimulus. PMID:23028470

Delwig, Anton; Logan, Anne M; Copenhagen, David R; Ahn, Andrew H

2012-09-13

243

Recognition of point-light biological motion: mu rhythms and mirror neuron activity.  

PubMed

Changes in power in the mu frequency band (8-13Hz) of the electroencephalogram (EEG) is thought to indirectly reflect the activity of mirror neurons in premotor cortex. Activation of these neurons by self-performed, observed or imagined motor actions is assumed to produce asynchronous firing and a reduction in mu rhythm oscillation (referred to as mu suppression) in sensorimotor cortex. A recent fMRI study by Saygin et al. [Saygin AP, Wilson SM, Hagler Jr DJ, Bates E, Sereno MI. Point-light biological motion perception activates human premotor cortex. J Neurosci 2004;24:6181-8] revealed that the premotor brain regions containing mirror-neurons are also activated in response to point-light human motion. The perceived movement of these light cues are integrated into one percept of a complete human action (e.g. jumping jacks), rather than seen as individual moving lights. The present study examined whether recruitment of the mirror neuron system, as reflected in mu rhythm suppression, mediates recognition of point-light biological motion. Changes in mu power were recorded while subjects viewed point-light biological motion videos, matched scrambled versions of these animations, and visual white-noise (baseline). The results revealed that point-light biological animations produced mu suppression relative to baseline, while scrambled versions of these animations did not. This supports the hypothesis that the mirror neuron system is involved in inferring human actions by recovering object information from sparse input. PMID:17658625

Ulloa, Erlinda R; Pineda, Jaime A

2007-06-19

244

Accuracy of intensity and inclinometer output of three activity monitors for identification of sedentary behavior and light-intensity activity.  

PubMed

Purpose. To examine the accuracy of intensity and inclinometer output of three physical activity monitors during various sedentary and light-intensity activities. Methods. Thirty-six participants wore three physical activity monitors (ActiGraph GT1M, ActiGraph GT3X+, and StepWatch) while completing sedentary (lying, sitting watching television, sitting using computer, and standing still) light (walking 1.0?mph, pedaling 7.0?mph, pedaling 15.0?mph) intensity activities under controlled settings. Accuracy for correctly categorizing intensity was assessed for each monitor and threshold. Accuracy of the GT3X+ inclinometer function (GT3X+Incl) for correctly identifying anatomical position was also assessed. Percentage agreement between direct observation and the monitor recorded time spent in sedentary behavior and light intensity was examined. Results. All monitors using all thresholds accurately identified over 80% of sedentary behaviors and 60% of light-intensity walking time based on intensity output. The StepWatch was the most accurate in detecting pedaling time but unable to detect pedal workload. The GT3X+Incl accurately identified anatomical position during 70% of all activities but demonstrated limitations in discriminating between activities of differing intensity. Conclusions. Our findings suggest that all three monitors accurately measure most sedentary and light-intensity activities although choice of monitors should be based on study-specific needs. PMID:22175006

Carr, Lucas J; Mahar, Matthew T

2011-11-13

245

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

246

14 CFR 29.757 - Hull and auxiliary float strength.  

Code of Federal Regulations, 2013 CFR

...hull, and auxiliary floats if used, must withstand the water loads prescribed by § 29.519 with a rational and conservative distribution of local and distributed water pressures over the hull and float bottom. [Amdt....

2013-01-01

247

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

248

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

249

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

250

Exploiting Idle Floating-Point Resources for Integer Execution  

Microsoft Academic Search

In conventional superscalar microarchitectures with partitioned integer and floating-point resources, all floating-point resources are idle during execution of integer programs. Palacharla and Smith [26] addressed this drawback and proposed that the floating-point subsystem be augmented to support integer operations. The hardware changes required are expected to be fairly minimal.To exploit these idle floating resources, the compiler must identify integer code

S. Subramanya Sastry; Subbarao Palacharla; James E. Smith

1998-01-01

251

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

PubMed Central

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

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

2006-01-01

252

Colloidal Quantum Dot Active Layers for Light Emitting Diodes  

Microsoft Academic Search

Nanotechnology is proliferating at a rapid rate in many areas including semiconductor lasers, biotechnology, and optoelectronics, as researchers create applications which capitalize on the unique advantages operating on the nanoscale afford them. In the case of semiconductor lasers it was found that by creating active layers on order of the de Broglie wavelength in all spatial directions, the movement of

J. Pagan; E. B. Stokes; M. Ahrens; K. Patel; M. O'Steen

2005-01-01

253

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

254

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

255

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

256

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

257

Repair of floating offshore units using bonded fibre composite materials  

Microsoft Academic Search

On ships, tankers and similar vessels structural defects such as cracks and corrosion damage are typically repaired by welding. However, welding is unwanted hotwork on floating offshore units (FOUs) such as floating, production, storage and offloading (FPSO) and floating, storage and offloading (FSO) vessels because it requires shutdown of parts of the vessel thus resulting in expensive production delays. Bonded

D. McGeorge; A. T. Echtermeyer; K. H. Leong; B. Melve; M. Robinson; K. P. Fischer

2009-01-01

258

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

259

Insertion loss prediction of floating floors used in ship cabins  

Microsoft Academic Search

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

Sun-Il Cha; Ho-Hwan Chun

2008-01-01

260

External Resource: Why Do Astronauts Float in Space?  

NSDL National Science Digital Library

This NASA video segment explains why objects seem to float in space. Viewers learn that an apple that floats in space is really in a state of freefall. Since the whole space shuttle is also in freefall, the apple seems to float. An animation of a person i

1900-01-01

261

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

262

Floating reference frames for flexible spacecraft  

Microsoft Academic Search

Floating reference frames which move with the flexible body under dynamic analysis offer the advantages of a linear vibration analysis in the presence of large system rotations. When the deformations of an elastic continuum are expanded in terms of the free-free modes on an unconstrained system, the rigid body modes are found to be fixed in a reference frame called

J. R. Canavin; P. W. Likins

1977-01-01

263

24-Bit Floating-Point DSP.  

National Technical Information Service (NTIS)

The article reports on a new high-speed 24-bit floating point DSP (digital-signal processor) and its development tools. The DSP features a short 75ns instruction cycle and low 750m W power dissipation. Other features include a large memory space, internal...

T. Fujiyama Y. Shimazu T. Tokuda S. Tsujimichi

1989-01-01

264

Creep theory for a floating ice sheet  

Microsoft Academic Search

The problem investigated in this thesis is the prediction of the deflection and stresses in a floating ice sheet under loads which act over a long period of time. This problem is currently important for oil exploration offshore in the Arctic. A review of analytical methods for predicting the bearing capacity of an ice sheet is given. The problem is

D. E. Nevel

1976-01-01

265

The salinity of a floating forest  

Microsoft Academic Search

Joachim Scheven has proposed an interesting theory that the Euro-American coals have not grown in place but formed when a huge forest of floating aquatic plants was swept on shore and buried in the catastrophe of Noah's Flood. Scheven's video 1 and published material 2-5 indicates that the Lepidendron and Sigillaria species of the Carbon- iferous coals were aquatic plants.

Wesley Bruce

2002-01-01

266

The DSP decision: fixed point or floating?  

Microsoft Academic Search

The rapid expansion of the market in applications of the digital signal processor has unloosed a flood of diverse chips. Design engineers are being inundated with altogether too much information to absorb. Still, the problem does become more manageable once it is decided whether a fixed-point or a floating point math unit should be basic to the digital signal processor

C. Inacio; D. Ombres

1996-01-01

267

40MM Target Marker (Floating), TMF-1.  

National Technical Information Service (NTIS)

This is the Final Report of the 40MM Target Marker (Floating), TMF-1, program. The purpose of this program was to prove the feasibility of and to design, develop and test a floatable target marker in a 40mm configuration that can be fired from either the ...

J. A. D'Andrea

1971-01-01

268

On building mobility models for floating objects  

Microsoft Academic Search

We present a general framework for building mobility models for floating objects. Such models are useful for studying the behavior of wireless sensors that are deployed to drift along rivers, lakes, oceans, or debris flows. These sensors may be used to track toxic wastes in the water, to study hydrology, or to warn natural hazards. While existing mobility models concentrate

Huang-chen Lee; Chun-yu Lin; Shang-wen Hsu; Chung-ta King

2009-01-01

269

Heat recovery and floating condensing in supermarkets  

Microsoft Academic Search

Supermarkets are great energy users in many countries. The potential for increased energy efficiency is large. One option is to utilize heat recovery (or heat reclaim) from condensers to heat the premises. Obviously this option is only interesting in relatively cold areas such as northern Europe, Canada, etc. An alternative to heat recovery is floating condensing pressure, which improves the

Jaime Arias; Per Lundqvist

2006-01-01

270

An introduction to deepwater floating drilling operations  

Microsoft Academic Search

Deepwater drilling is discussed from selecting vessels and hardware to safety precautions and personnel. The contents include drilling from a floating vessel; planning and organizing deepwater drilling operations; drill vessels; drilling systems; mooring systems; auxiliary vessels; well-control and communications; subsea guide bases; subsea blowout preventers; marine-riser systems; drill-stem testing; safety and efficiency; and future developments. (JMT)

1972-01-01

271

Floating drilling rig apparatus and method  

Microsoft Academic Search

This patent describes an apparatus adapted for use with a floating drilling rig having a marine riser including a telescopic joint. The telescopic joint has a guide\\/index key. The joint has an upwardly facing unterminated connector for a riser choke\\/kill line. The apparatus comprises: a terminal end assembly, including: a frame, yoke means slidably disposed on the frame for securing

1987-01-01

272

[The theory of floating eye model].  

PubMed

Analytical construction of the eye floating was carried out. Buoyancy equations were deduced including the equation for dynamic equilibrium at various eye (head) orientations in space. Design formulae were derived for evaluating buoyancy force on the eye, negative pressure, stability and compensational (heeling) forces of the eye muscles. PMID:2346754

Galoian, V R

273

PLM floating-point interface program  

Microsoft Academic Search

A major failing of Intel's PLM language is its inability to handle scientific notation (floating-point) calculations. An interface program that allows PLM to perform such calculations is described. A comparison of this modified PLM with an assembly language program has shown PLM's effectiveness in reducing the cost of a project. (auth)

C. Paoni; M. Maples

1976-01-01

274

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

275

NSLS 2003 ACTIVITY REPORT (NATIONAL SYNCHROTRON LIGHT SOURCE ACTIVITY REPORT 2003)  

SciTech Connect

The scientific productivity of the NSLS continues to be outstanding and the research conducted here has high impact. 2003 was no exception and some of the many highlights from this year's research activity are included in this Activity Report. We are especially pleased that one of our users, Professor Roderick MacKinnon (Rockefeller University), was the co-recipient of the 2003 Nobel Prize in Chemistry for work, much of which was done at the NSLS, explaining how proteins known as ion channels help to generate nerve impulses. It is also a particular pleasure to note that NSLS accelerator physicist Li Hua Yu was awarded the 2003 International Free Electron Laser Prize in recognition of his outstanding achievements, especially demonstrating High Gain Harmonic Generation (HGHG) at the DUV-FEL. Our vision for the NSLS in the next five to 10 years is for it to continue to serve as a vital resource for the nation and especially for the strong Northeast research community. To accomplish this, we are working to preserve and enhance its outstanding scientific productivity by providing increased user support and upgrading beamline and endstation instrumentation. For example, this past year we collaborated with scientists from the Albert Einstein College of Medicine and the BNL Biology Department to develop a new undulator beamline, X29, to meet the needs of macromolecular crystallography for high brightness x-rays. A new endstation on the undulator beamline X13B is being equipped with optics and instrumentation for microdiffraction and microprobe experiments. The wiggler beamline, X21, is being upgraded to provide high intensity and increased capacity for small angle x-ray scattering experiments on nanotemplated soft matter, biomaterials, and other systems. We are collaborating with the BNL Center for Functional Nanomaterials to develop a beamline for LEEM/PEEM studies, which will add important new capabilities for nanoscience and catalysis research. A new high-speed, high-resolution curved position sensitive detector for powder diffraction was also developed and made available to users to enable time-resolved studies of reaction mechanisms, phase transformations, chemical kinetics, and material dynamics. At the DUV-FEL, this past year saw the achievement of HGHG light at 266 nm, with a substantial third harmonic at 89 nm. User science experiments were initiated and published in Physical Review Letters and a successful workshop was held to identify the new scientific opportunities in the chemical sciences enabled by this unique light source. These and many other important projects are described more fully in the Facility Report.

MILLER,L.

2004-05-01

276

A BELL1-like gene of potato is light activated and wound inducible.  

PubMed

BELL1-like transcription factors interact with their protein partners from the KNOTTED1 family to bind to target genes and regulate numerous developmental and metabolic processes. In potato (Solanum tuberosum), the BELL1 transcription factor StBEL5 and its protein partner POTH1 regulate tuber formation by affecting hormone levels. Overexpression of StBEL5 in transgenic lines produces plants that consistently exhibit enhanced tuber formation, and the mRNA of this gene moves through phloem cells in a long-distance signaling pathway regulated by photoperiod. Whereas photoperiod mediates the movement of StBEL5 RNA, activation of transcription of the StBEL5 gene in leaves is regulated by white light, regardless of photoperiod or light intensity. Illumination with either red or blue light induces the StBEL5 promoter, whereas far-red light had no effect. As expected, the StBEL5 promoter harbors numerous conventional light-responsive cis-acting elements like GT1, GATA, and AT1 motifs. Deletion constructs were analyzed to determine what sequences are involved in light activation. Transcriptional activity was also mediated by wounding on stems, insect predation on leaves, and photoperiod in stolons. These results demonstrate that StBEL5 gene activity in the leaf is correlated with wavelengths optimal for photosynthesis. The number of factors that affect the StBEL5 promoter supports the premise that the BELL1-like genes play a role in a wide range of functions. PMID:17921341

Chatterjee, Mithu; Banerjee, Anjan K; Hannapel, David J

2007-10-05

277

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

PubMed Central

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

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

2010-01-01

278

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

279

2001 NSLS ACTIVITY REPORT (NATIONAL SYNCHROTRON LIGHT SOURCE).  

SciTech Connect

The year 2001 has been another highly productive year at the NSLS, with over 2500 users, including 720 first time users, conducting nearly 1200 experiments in fields ranging from the life, materials, chemical, and environmental sciences to applied science and technology. An impressive array of highlights from this scientific activity is included in this Activity Report. They include the first demonstration of a direct structural probe of the superconducting ground state in the cuprates by utilizing anomalous soft x-ray resonance effects to selectively enhance the scattering from doped holes. Another highly significant result was the determination of the structure of the potassium channel membrane protein. This is especially significant as it provides insight into how the channel functions and how it selects a particular kind of ion. In the nanoscience area, small angle x-ray scattering measurements played an essential role in determining that preferential sequestering of tailored metal nanocrystals into a self-assembled lamellar diblock copolymer can produce high quality metallodielectric photonic bandgap structures, demonstrating the potential of these nanocomposites for photonic crystal engineering. The infrared microscopy program continued to yield noteworthy results, including an important study that characterized the types and abundances of organic materials in contaminated and uncontaminated sediments from the New York/New Jersey Harbor. These results will be useful in devising improved methods for the destruction or removal of these environmental contaminants.

CORWIN, M.A.

2002-05-01

280

Photocatalytic activation of TiO 2 under visible light using Acid Red 44  

Microsoft Academic Search

The activation of TiO2 photocatalyst for photocatalysis under the visible light using Acid Red 44 (C10H7N=NC10H3(SO3Na)2OH) is described. Adjustment of the pH enhanced the photocatalytic activation of TiO2 in the presence of visible light. This confirms that the adsorption of a dye on TiO2 surface is an important factor in dye-photosensitization. The differences in the photocatalytic activation mechanism under visible

Jungwoo Moon; Chang Yeon Yun; Kyung-Won Chung; Min-Soo Kang; Jongheop Yi

2003-01-01

281

FIBER AND INTEGRATED OPTICS: Propagation of radiation in a light-induced active waveguide  

NASA Astrophysics Data System (ADS)

An investigation is reported of the properties of the normal modes of an active light-induced waveguide. It is shown that, in contrast to a dielectric waveguide, the presence of the active component may increase considerably the number of the normal modes and the angles of their scattering. In the case of an active light-induced waveguide in the form of a thin filament the normal modes exist and are amplified only in the case when the nonlinear correction to the refractive index is positive.

Afanas'ev, Anatolii A.; Samson, B. A.; Drits, V. V.; Yukhimenko, S. I.; Yakite, R. V.

1990-10-01

282

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

SciTech Connect

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

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

1981-01-01

283

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

PubMed Central

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

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

1979-01-01

284

Rhythmic activity responses of the fiddler crab Uca crenulata to artificial tides and artificial light  

Microsoft Academic Search

The fiddler crab Uca crenulata, from California (USA), was exposed to artificial tides in order to differentiate between the influence of a tidal cycle from that of a light-dark cycle on its locomotor activity. Most crabs could be well synchronized by tides, but the activity patterns of other crabs was merely exogenously reinforced. Under constant conditions, after tidal treatment, crabs

H.-W. Honegger

1973-01-01

285

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

286

Block of gap junctions eliminates aberrant activity and restores light responses during retinal degeneration.  

PubMed

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. PMID:23986234

Toychiev, Abduqodir H; Ivanova, Elena; Yee, Christopher W; Sagdullaev, Botir T

2013-08-28

287

Variable optical activation of human cone photoreceptors visualized using a short coherence light source  

PubMed Central

It has been shown that after a visible stimulus, optical oscillations of nearly all cone photoreceptors can be observed using long coherence length light and in a few cones using short coherence length light. Here, we show that after exposure to a visible stimulus, a short coherence length imaging source reveals light-evoked oscillation signals in a large number of cones. More than 80% of cones in a given retinal area are activated (modulation in the reflectance signal) after stimulation, and the pattern of their activation can be subjectively classified into one of four categories. The application of light-evoked signal detection techniques for in vivo retinal imaging may prove useful for assessing the functional status of cones in normal and diseased retinae.

Rha, Jungtae; Schroeder, Brett; Godara, Pooja; Carroll, Joseph

2012-01-01

288

Visual ecology of Indian carpenter bees I: light intensities and flight activity.  

PubMed

Bees are mostly active during the daytime, but nocturnality has been reported in some bee families. We studied temporal flight activity in three species of carpenter bees (genus Xylocopa) in relation to light intensities. X. leucothorax is diurnal, X. tenuiscapa is largely diurnal being only occasionally crepuscular, while X. tranquebarica is truly nocturnal. Occasional forays into dim light by X. tenuiscapa are likely to be due to the availability of richly rewarding Heterophragma quadriloculare (Bignoniaceae) flowers, which open at night. X. tranquebarica can fly even during the moonless parts of nights when light intensities were lower than 10(-5) cd m(-2), which makes this species the only truly nocturnal bee known so far. Other known dim-light species fly during crepuscular or moonlit periods. We compare eye and body sizes with other known diurnal and dim-light bees. We conclude that while extremely large ocellar diameters, large eye size:body size ratio, large number of ommatidia and large ommatidial diameters are all adaptations to dim-light foraging, these alone do not sufficiently explain the flights of X. tranquebarica in extremely dim light. We hypothesise that additional adaptations must confer extreme nocturnality in X. tranquebarica. PMID:18094978

Somanathan, Hema; Borges, Renee M; Warrant, Eric J; Kelber, Almut

2007-12-20

289

Caged glucosamine-6-phosphate for the light-control of riboswitch activity.  

PubMed

We have synthesized a light-activatable ("caged") derivative of glucosamine-6-phosphate (GlcN6P), which only upon irradiation becomes a cofactor for the glmS riboswitch. This glmS riboswitch maintains its activity when embedded in the 3'-untranslated region of eukaryotic mRNA molecules and caged GlcN6P reduces the amount of translated EGFP upon irradiation with light in vitro. PMID:22005771

Wulffen, Bernhard; Buff, Maximilian Clemens Rudolf; Pofahl, Monika; Mayer, Günter; Heckel, Alexander

2011-10-17

290

Enhanced visible-light-response photocatalytic activity of bismuth ferrite nanoparticles  

Microsoft Academic Search

Multiferroic BiFeO3 nanoparticles were prepared by a sol–gel rapid calcination technique with average diameter of 35nm with narrow size distribution. The band gap was determined to be 2.06eV, indicating their potential application as visible-light-response photocatalyst. The photocatalytic behaviors of BiFeO3 nanoparticles were estimated by the degradation of Rhodamine B (RhB) under visible light irradiation. And the photocatalytic activities under different

Xiong Wang; Ying Lin; Xifeng Ding; Jinguo Jiang

2011-01-01

291

Floating photocatalysts based on TiO 2 grafted on expanded polystyrene beads for the solar degradation of dyes  

Microsoft Academic Search

In this work, a highly active, low cost, simple and robust floating photocatalyst based on TiO2 P25 grafted on expanded polystyrene (EPS) beads was developed. SEM and TG analyses showed that ca. 18wt% of TiO2 can be permanently grafted on the surface of EPS particles. This floating photocatalyst showed high efficiency for the degradation of three different dyes, i.e. methylene

F. Magalhães; R. M. Lago

2009-01-01

292

Activators of Peroxisome Proliferator-Activated Receptors Protect Human Skin from Ultraviolet-B-Light-Induced Inflammation  

Microsoft Academic Search

Peroxisome proliferator-activated receptors (PPAR) are members of a nuclear receptor superfamily, which were initially described in the context of fatty acid degradation and adipocyte differentiation. In this study we tested the hypothesis that peroxisome proliferator-activated receptor activation also controls inflammation. In an in vitro model with human keratinocytes inflammation was mimicked by irradiation with ultraviolet B light (150 mJ per

Stefan Kippenberger; Stefan Marcel Loitsch; Marcella Grundmann-Kollmann; Stephanie Simon; Tu-Anh Dang; Katja Hardt-Weinelt; Roland Kaufmann; August Bernd

2001-01-01

293

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

294

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

295

Studies on light absorption and photochemical activity changes in chloroplast suspensions and leaves due to light scattering and light filtration across chloroplast and vegetation layers  

Microsoft Academic Search

An experimental analysis is presented concerning the effect on relative light absorption by the two photosystems caused by (a) a highly light scattering environment (the “detour effect”) and (b) light filtration across successive chloroplast layers (the “light attenuation effect”). Both suspensions of isolated chloroplasts and leaves were employed.

Flavio Massimo Garlaschi; Giuseppe Zucchelli; Robert Charles Jennings

1989-01-01

296

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

297

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

298

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

299

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

PubMed

We investigated whether low intensity dawn-dusk simulation (DDS), a 'naturalistic' form of light therapy designed to embed sleep in its accustomed phase, could improve the disturbed circadian rest-activity cycle, nocturnal sleep and and/or cognitive functions in dementia. A protocol of 3 weeks each of baseline, treatment and follow-up was completed by 13 patients (85yr old+/-5yr, MMSE 14+/-5; n=9 DDS versus n=4 'placebo' dim red light) who wore an activity/lux monitor throughout. There were no significant changes in clinical or cognitive status, nor modification of circadian stability or amplitude characteristics of the rest-activity cycle. However, two aspects of sleep responded to DDS but not to dim red light. The main sleep episode was 1:14h earlier during treatment (p=0.03) compared with before and after DDS. With respect to actimetry-determined sleep variables, the DDS group tended to have shortened 'sleep latency', longer 'sleep duration', more nocturnal immobility and less nocturnal activity than the dim red group (p<0.1). In parallel, nighttime light exposure tended to be reduced (p=0.07). These promising findings-after only 3 weeks of light treatment in elderly patients with advanced dementia-suggest that the circadian timing system remains functionally responsive even to low intensity DDS light. Increasing zeitgeber strength is an important strategy for improving sleep quality and timing in dementia, and DDS light therapy may provide one of the appropriate means to do so. PMID:12543279

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

300

Posterior hypothalamic modulation of light-evoked trigeminal neural activity and lacrimation.  

PubMed

Enhanced light sensitivity is a common feature of many neuro-ophthalmic conditions and some chronic headaches. Previously we reported that the bright light-evoked increases in trigeminal brainstem neural activity and lacrimation depended on a neurovascular link within the eye (Okamoto et al., 2012). However, the supraspinal pathways necessary for these light-evoked responses are not well defined. To assess the contribution of the posterior hypothalamic area (PH), a brain region closely associated with control of autonomic outflow, we injected bicuculline methiodide (BMI), a GABAa receptor antagonist, into the PH and determined its effect on the encoding properties of ocular neurons at the ventrolateral trigeminal interpolaris/caudalis transition (Vi/Vc) and caudalis/upper cervical cord junction (Vc/C1) regions and on reflex lacrimation in male rats under isoflurane anesthesia. BMI markedly reduced light-evoked (>80%) responses of Vi/Vc and Vc/C1 neurons at 10 min with partial recovery by 50 min after injection. BMI also reduced (>35%) the convergent cutaneous receptive field area of Vi/Vc and Vc/C1 ocular neurons indicating that both intra-ocular and periorbital cutaneous inputs were affected by changes in PH outflow. Light-evoked lacrimation was reduced by >35% at 10 min after BMI, while resting mean arterial pressure increased promptly and remained elevated (>20 mmHg) throughout the 50-min post-injection period. These results suggested that PH stimulation, acting in part through increased sympathetic activity, significantly inhibited light- and facial skin-evoked activity of ocular neurons at the Vi/Vc and Vc/C1 region. These data provide further support for the hypothesis that autonomic outflow plays a critical role in mediating light-evoked trigeminal brainstem neural activity and reflex lacrimation. PMID:23643978

Katagiri, A; Okamoto, K; Thompson, R; Bereiter, D A

2013-04-30

301

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

302

Calcium Increases in Retinal Glial Cells Evoked by Light-Induced Neuronal Activity  

PubMed Central

Electrical stimulation of neurons in brain slices evokes increases in cytoplasmic Ca2+ in neighboring astrocytes. The present study tests whether similar neuron-to-glial signaling occurs in the isolated rat retina in response to light stimulation. Results demonstrate that Müller cells, the principal retinal glial cells, generate transient increases in Ca2+under constant illumination. A flickering light stimulus increases the occurrence of these Ca2+transients. Antidromic activation of ganglion cell axons also increases the generation of Müller cell Ca2+transients. The increases in Ca2+transients evoked by light and antidromic stimulation are blocked by the purinergic antagonist suramin and by TTX. The addition of adenosine greatly potentiates the response to light, with light ON evoking large Ca2+increases in Müller cells. Suramin, apyrase (an ATP-hydrolyzing enzyme), and TTX substantially reduce the adenosine-potentiated response. NMDA, metabotropic glutamate, GABAB , and muscarinic receptor antagonists, in contrast, are mainly ineffective in blocking the response. Light-evoked Ca2+responses begin in Müller cell processes within the inner plexiform (synaptic) layer of the retina and then spread into cell endfeet at the inner retinal surface. These results represent the first demonstration that Ca2+increases in CNS glia can be evoked by a natural stimulus (light flashes). The results suggest that neuron-to-glia signaling in the retina is mediated by neuronal release of ATP, most likely from amacrine and/or ganglion cells, and that the response is augmented under pathological conditions when adenosine levels increase.

Newman, Eric A.

2005-01-01

303

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

304

Twin countershaft transmission with floating main shaft  

SciTech Connect

A multi-speed transmission is described comprising, in combination: a housing; a pair of spaced parallel main countershafts mounted for rotation within the housing and being spatially fixed therein; means for supplying input power to both of the main countershafts; a plurality of pairs of driving gears mounted on the main countershafts, each gear of a pair being substantially identical and positioned on a respective one of the main countershafts at axially aligned locations along a floating mainshaft; the floating main shaft having input and output ends, the main shaft being located within the housing between and parallel to the main countershafts and having its output end extending beyond the main countershafts with no internal or external bearings or other support at or adjacent its ends under torque delivering conditions.

Loeffler, J.M.

1989-02-28

305

OCD metrology by floating n/k  

NASA Astrophysics Data System (ADS)

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

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

2007-03-01

306

Floating behavior of hydrophobic glass spheres.  

PubMed

When a hydrophobic solid sphere is floating on water or salt solutions with different concentrations, it is at equilibrium under the impact of gravity, buoyancy force, and curvature force, the component of surface tension in the vertical direction. We have changed the diameters of the spheres and the concentrations of the two selected salts, NaCl and NaNO(3), to study the floating behaviors of these spheres and the contributions of surface tension and buoyancy force to their floatation. Generally speaking, the surface tension plays a more important role than the buoyancy force when the gravity is small, but the buoyancy force plays an identical or a more important role when the spheres are big enough. The wettability of the spheres significantly influences the height below the contact perimeter especially in salt solutions. The theoretical calculation meniscus slope angles at the sphere three-phase contact line are in agreement with experimental results. PMID:19464018

Liu, Xinjie; Wang, Xiaolong; Liang, Yongmin; Zhou, Feng

2009-04-16

307

Sink or Float. Modified Primary. Revised. Anchorage School District Elementary Science Program.  

ERIC Educational Resources Information Center

This publication provides information and activities for teaching about water, whether certain objects will sink or float, and process skills including observing, classifying, inferring, measuring, predicting, and collecting and interpreting data. There are 14 lessons in the unit. The first four lessons deal with the classification of objects and…

Defendorf, Jean, Ed.

308

Teaching Strategies and Conceptual Change: Sinking and Floating at Elementary School Level.  

ERIC Educational Resources Information Center

This paper describes the design and results of a study carried out with elementary pupils ages 8-9 years on the topic of sinking and floating, with the aim of checking the validity of a general scheme for classroom activities based on a constructivist perspective. Children's "ways of looking" at buoyancy and the production of materials that could…

Tomasini, N. Grimellini; And Others

309

Sink or Float. Modified Primary. Revised. Anchorage School District Elementary Science Program.  

ERIC Educational Resources Information Center

|This publication provides information and activities for teaching about water, whether certain objects will sink or float, and process skills including observing, classifying, inferring, measuring, predicting, and collecting and interpreting data. There are 14 lessons in the unit. The first four lessons deal with the classification of objects and…

Defendorf, Jean, Ed.

310

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

311

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

312

Finite Element Analysis of a Floating Microstimulator  

PubMed Central

Analytical solutions for voltage fields in a volume conductor are available only for ideal electrodes with radially symmetric contacts and infinitely extending substrates. Practical electrodes for neural stimulation may have asymmetric contacts and finite substrate dimensions and hence deviate from the ideal geometries. For instance, it needs to be determined if the analytical solutions are adequate for simulations of narrow shank electrodes where the substrate width is comparable to the size of the contacts. As an extension to this problem, a “floating” stimulator can be envisioned where the substrate would be finite in all directions. The question then becomes how small this floating stimulator can be made before its stimulation strength is compromised by the decrease in the medium impedance between the contacts as the contacts are approaching each other. We used finite element modeling to solve the voltage and current profiles generated by these radially asymmetric electrode geometries in a volume conductor. The simulation results suggest that both the substrate size and the bipolar contact separation influence the voltage field when these parameters are as small as a few times the contact size. Both of these effects are larger for increasing elevations from the contact surface, and even stronger for floating electrodes (finite substrate in all directions) than the shank-type electrodes. Location of the contacts on the floating electrode also plays a role in determining the voltage field. The voltage field for any device size and current, and any specific resistance of the volume conductor can be predicted from these results so long as the aspect ratios are preserved.

Sahin, Mesut; Ur-Rahman, Syed S.

2011-01-01

313

Floating-Gate MOS Synapse Transistors  

Microsoft Academic Search

Our goal is to develop silicon learning systems. One impediment to achieving this goal has been the lack of a simple circuit\\u000a element combining nonvolatile analog memory storage with locally computed memory updates. Existing circuits [63, 132] typically\\u000a are large and complex; the nonvolatile floating-gate devices, such as EEPROM transistors, typically are optimized for binary-valued\\u000a storage [17], and do not

Chris Diorio; Paul Hasler; Bradley A. Minch; Carver Mead

314

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

315

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

316

Floating boom performance under waves and currents.  

PubMed

Floating booms constitute a fundamental tool for the protection of marine and coastal ecosystems against accidental oil spills. Their containment performances in exposed areas are often impaired by the action of waves, currents and winds in a manner which is dependent on the boom's response as a floating body, and which is not fully understood at present. In this work the relationship between the design parameters of a floating boom section and its efficiency against the mode of failure by drainage under a variety of wave and current combinations is investigated by means of physical modelling. Seven boom models with different geometries and buoyancy-weight ratios are tested with an experimental setup that allows them to have and rotate freely. The model displacements under waves (both regular and irregular) and currents, as well as those of the free surface adjacent to the model, are measured with a Computer Vision system developed ad hoc. Two efficiency parameters are defined-the significant and minimum effective boom drafts-and applied to the results of an experimental campaign involving 315 laboratory tests. Thus, the manner in which the design parameters influence the boom's efficiency under different wave and current conditions is established. PMID:19800166

Castro, A; Iglesias, G; Carballo, R; Fraguela, J A

2009-09-16

317

Older adults' rest-activity and light exposure patterns in the home setting: a methodological case study  

PubMed Central

Background This methodological case study describes light exposure and rest-activity patterns in an older adult with dementia and his caregiver spouse. Methods Two devices were used to measure rest-activity and light exposure data: a wrist-worn actigraph with a light sensor to record full spectrum light exposure data and an eye-level wavelength sensitive light meter (Daysimeter™). The wife wore both devices simultaneously; the husband wore only the actigraph. Results There were minimal feasibility issues in using the devices in the home setting. The wife’s light exposure was considerably better than her husband’s, but she spent little time in bright lighting. Her circadian stimulus (CS) and activity values suggest high level of circadian disruption. Conclusion This case study provides beginning support for the use of the Daysimeter in the home setting while also highlighting unrecognized circadian disturbances and very low light levels in an older couple’s home.

Higgins, Patricia A.; Hornick, Thomas R.; Figueiro, Mariana G.

2012-01-01

318

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

319

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

320

Photosynthetic activity and growth analysis of the plant {Costus spicatus} cultivated under different light conditions  

NASA Astrophysics Data System (ADS)

The aim of the present work was to evaluate the effect of different radiance levels (25%, 50% and 100% of full sunlight) in growth (height, leaf area, number of leaves) and photosynthetic activity of the plant Costus spicatus, popularly known in Brazil as Caninha do Brejo. Photoacoustic (PA) measurements were performed in order to evaluate comparatively the photosynthetic activity rate of plants submitted to different light intensity regimes. The results obtained show that plants maintained under low light intensity levels (25% of sunlight) presented higher height, leaf area and number of leaves, while plants grown under full sunlight presented higher radicular length. PA measurements indicated higher photosynthetic rate for plants grown under 50% of full sunlight, but plants developed under 25% of full sunlight (75% shading) presented the fastest response to light incidence (photosynthetic induction).

Campos, V. M.; Pasin, L. A. A. P.; Barja, P. R.

2008-01-01

321

STAT3 activation in photoreceptors by leukemia inhibitory factor is associated with protection from light damage.  

PubMed

Members of the interleukin-6 cytokine family, including leukemia inhibitory factor (LIF), signal through gp130. The neuroprotective role of gp130 activation has been widely demonstrated in both CNS and PNS, but the mechanism by which this is accomplished is not well established. We investigated temporal and cell-specific activation of signaling pathways induced by LIF in the mature mouse retina. Intravitreal injection of LIF preserved photoreceptor function and prevented photoreceptor cell death from light-induced oxidative damage in a dose-dependent manner (2 days post-injection). A therapeutic dose of LIF induced rapid and sustained activation of signal transducer and activator of transcription (STAT) 3. Activated STAT3 was localized to all the retinal neurons and glial cells, including photoreceptors. Activation of extracellular signal-regulated kinase 1 and 2 was robust but transient in Müller glial cells, and undetectable at the time of light exposure. Akt was not activated by LIF. We also show that at the time of neuroprotection, STAT3 but not extracellular signal-regulated kinase 1 and 2 or the Akt pathways was active in LIF-treated retinas, and activated STAT3 was clearly localized in transcriptionally active areas of photoreceptor nuclei. Our data suggest that photoreceptor protection in response to LIF can be directly mediated by activation of STAT3 in photoreceptors. PMID:18088375

Ueki, Yumi; Wang, Jiangang; Chollangi, Srinivas; Ash, John D

2007-12-10

322

Optics and Light Activities for Teachers of all Grade Levels from Easily Obtainable Supplies  

NASA Astrophysics Data System (ADS)

Several hands-on activities in light and optics covering selected topics will be discussed in the context of home labs and how such activities can be incorporated into a distance-learning or online web-based course utilizing the latest communication technologies and the Internet. The presentation will focus on activities that can be constructed from easy to obtain supplies as well as a commercially available kit that we are having made available. Activities for teachers at the elementary level will focus on understanding light rays, shadows, and reflection from plane surfaces; at the middle school level will focus on curved mirrors and lenses, dispersion, and drawing ray diagrams; at the high school level will focus on Snell's law, the lens equation, wave interference, polarization, Young's experiment, and diffraction. A distance-learning, web-based course based on these home labs will be described. )

Lindgren, Richard; Hendricks, Curtis; Lucatorto, Lynn; McNeilus, Thomas; Thornton, Stephen

2010-02-01

323

Effect of Delayed Light-Cured Activation on Bond-Strengths between Composites and Adhesives  

Microsoft Academic Search

The objective of this study was to evaluate and compare the effect of times elapsed on the application of a single-step adhesive system and activation of light cured subsequently placed composite to the bond strength between composites and adhesives. This was an experimental study using fifteen teeth extracted human premolars, which were caries and pathology free. Sample of teeth were

S. M. Masudi; E. A. Padtong

324

Path tracking control of a laser light point by active visual servoing  

Microsoft Academic Search

Path tracking control of a laser light point (LLP) using an active camera is studied in this paper. The scope of the path could be out of the scene the camera in motion can capture at a time and no camera calibration is required. Two masking windows are defined, and only the images within the windows are processed in a

Ku Chin Lin

2000-01-01

325

Patterns of Synaptic Activity in Neural Networks Recorded by Light Emission from Synaptolucins  

Microsoft Academic Search

The emission of light, coupled to exocytosis, can in principle be utilized to monitor the activity of a large number of individual synapses simultaneously. To illustrate this concept, fusion proteins of Cypridina luciferase and synaptotagmin-I or VAMP-2\\/synaptobrevin (which we term ``synaptolucins'') were expressed in cultured hippocampal neurons with the help of viral vectors. Synaptolucins were targeted to synaptic vesicles and,

Gero Miesenbock; James E. Rothman

1997-01-01

326

Photophysical properties and photocatalytic activities of bismuth molybdates under visible light irradiation.  

PubMed

Aurivillius structure Bi(2)MoO(6) (BG: 2.70 eV) that is a low-temperature phase showed an intense absorption band in the visible light region and photocatalytic activity for O(2) evolution from an aqueous silver nitrate solution under visible light irradiation, among various bismuth molybdates (Bi(2)MoO(6), Bi(2)Mo(2)O(9), and Bi(2)Mo(3)O(12)) synthesized by solid-state and reflux reactions. Bi(2)Mo(3)O(12) (BG: 2.88 eV) also showed photocatalytic activity for O(2) evolution under full-arc irradiation of a Xe lamp (lambda > 300 nm). The photocatalytic activity of the Aurivillius structure Bi(2)MoO(6) prepared by the reflux method was dependent on the annealing temperature after the preparation. The crystallinity was the important factor for the activity. Calculation by the density functional method indicated that the conduction band of Aurivillius structure Bi(2)MoO(6) was made up of Mo 4d orbitals. It turned out that the visible-light absorption of this photocatalyst was due to the transition from the valence band consisting of O 2p orbitals to the conduction band. The corner-sharing structure of the MoO(6) octahedra contributed to the visible light response and the photocatalytic performance because excitation energy and/or photogenerated electron and hole pairs began to migrate easily in the Aurivillius structure. PMID:16956264

Shimodaira, Yoshiki; Kato, Hideki; Kobayashi, Hisayoshi; Kudo, Akihiko

2006-09-14

327

A new pixel circuit for active matrix organic light emitting diodes  

Microsoft Academic Search

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

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

2002-01-01

328

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

Microsoft Academic Search

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

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

1999-01-01

329

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

330

Photochemotherapy of intimal hyperplasia using Psoralen activated by uv light in porcine model  

Microsoft Academic Search

Psoralen activated by UVA light (PUVA) was investigated as a means of inhibiting smooth muscle cell proliferation resulting from balloon injury. Twenty kilogram domestic swine were anesthetized and underwent balloon angioplasty to create a 133% overstretch injury. Assignments of treatment and control were randomized between the left anterior descending (LAD) and circumflex (LCX) coronaries arteries. The animals were given with

Lisa A. Buckley; Kenton W. Gregory; Deborah T. Bahlman; Hanqun Shangguan; Henner Fahrenbach; Eli Rosenthal; Peter C. Block

1996-01-01

331

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

332

Enhanced light microscopic visualization of oxidase activity with the cerium capture method  

Microsoft Academic Search

Visualization methods for the light microscopic detection of the activity of oxidases after being localized with cerium ions as reported by Angermüller and Fahimi (1988a, b) are not suitable for the demonstration of H2O2-genrating oxidases at sites with low activity. Therefore, the cerium-diaminobenzidine (DAB) visualization procedure of these authors was modified. Nickel or cobalt ions were added to the DAB

R. Gossrau; C. J. F. Noorden; W. M. Frederiks

1989-01-01

333

Preparation of B-doped titania hollow sphere and its photocatalytic activity under visible light  

Microsoft Academic Search

In this study, B-doped titania hollow spheres were prepared using hydrothermally prepared carbon spheres as template. The photocatalytic activity of as-prepared hollow titania spheres was determined by degradation of Reactive Brilliant Red dye X-3B (C.I. reactive red 2) under visible light irradiation, and was compared to commercial P25 titania. It was revealed that the photocatalytic activity of the hollow titania

Jingjing Xu; Yanhui Ao; Mindong Chen

2009-01-01

334

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

335

Out-of-Equilibrium effects in suspensions of light-activated artificial microwimmers  

NASA Astrophysics Data System (ADS)

We present a new type of colloidal artificial swimmers propelled by the decomposition of hydrogen peroxide and activated by light. The effect is reversible and allows external control of the swimming/non swimming behavior of the particles. Moreover the bulk synthesis makes possible the study of very concentrated assemblies of monodisperse and identical microswimmers. These active agents are used to explore fancy effects of out-of-equilibrium systems, e.g. clustering, ``tugboat'' effect...

Palacci, Jeremie; Sacanna, Stefano; Pine, David; Chaikin, Paul

2011-11-01

336

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

337

Visible light photocatalytic activity of TiO 2\\/D-PVA for MO degradation  

Microsoft Academic Search

A novel visible light (VL) active photocatalyst (TiO2\\/D-PVA) was prepared in one portion of polyvinyl alcohol (PVA) and Ti(OH)4 by means of hydrothermal method, and the relationship between the prepared conditions and VL photocatalytic activity was investigated. The synthesized photocatalyst was characterized by XRD, UV–vis, XPS, FTIR and EPR. The results show that PVA was dehydrated to produce conjugated unsaturated

Yongzhong Wang; Mingqiang Zhong; Feng Chen; Jintao Yang

2009-01-01

338

In vitro photodynamic antimicrobial activity of methylene blue and endoscopic white light against Helicobacter pylori 26695.  

PubMed

Photodynamic therapy (PDT) is a method for inactivating cells (viral, bacterial and cancer cells) using photosensitizers (PS) and light of various wavelengths. Helicobacter pylori might be easily affected by light because it has few genes to repair light-induced DNA damage. In vitro PDT against H. pylori was conducted using endoscopic white light and methylene blue (MB) as the PS before application to in vivo study. The bactericidal effects were measured by counting viable cells after PDT. The degree of oxidative damage of DNA was confirmed using alkaline gel electrophoresis, real-time PCR (RT-PCR) and an assay of 8-hydroxy-2-deoxyguanosine (8-OHdG). In the control group, the number of viable cells was maintained constantly during the experiment. In the groups treated with either 0.2mg/mlMB alone or white light with 0.02mg/mlMB for 10min, bacteria decreased approximately a hundredfold. The killing effect increased proportionally to the PS concentration and the duration of irradiation. DNA damage by PDT proven by alkaline gel electrophoresis, RT-PCR and assay of 8-OHdG, was greater in PDT-treated groups than in control. PDT using MB and endoscopic white light showed effective bactericidal activity in vitro by oxidative DNA damage of H. pylori. PMID:20692848

Choi, Sung Sook; Lee, Hae Kyung; Chae, Hiun Suk

2010-07-15

339

Integrated light sources based on self-formed polymer waveguide doped with active medium  

NASA Astrophysics Data System (ADS)

The polymer-based photonic devices have promise as optical components integrated in convenient microchip systems because of ease in the deposition and microfabrication of polymer materials. Furthermore, since the polymers can be easily doped with luminescent materials such as organic dyes, the organic light source devices are also considerable as the integrated optical components. Especially the self-formation method of the fiber type waveguide using the dyedoped photopolymers, called as self-written active (SWA) waveguide technique, brings a simple fabrication scheme of the light sources integrated in the polymer photonic circuit. It has been demonstrated that an in-line optical amplifier and a Fabry-Perot type lasing cavity can be obtained by using the SWA waveguide technique. In this study we have employed this technique to fabricate an incoherent light source with a wideband emission. A serially cascaded SWA waveguide doped with the different organic dyes could be fabricated with a single exposure process. The cascaded SWA waveguide could act as an incoherent light source under UV light irradiation. This device can be expected as a probing light source for the label-free microchip system, which would be available for the biological sensing, environmental measurements, and medical diagnosis.

Sugimoto, S.; Kawaguchi, T.; Yamashita, K.

2012-05-01

340

Light-triggered modulation of cellular electrical activity by ruthenium diimine nanoswitches.  

PubMed

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

Rohan, Joyce G; Citron, Y Rose; Durrell, Alec C; Cheruzel, Lionel E; Gray, Harry B; Grubbs, Robert H; Humayun, Mark; Engisch, Kathrin L; Pikov, Victor; Chow, Robert H

2013-02-18

341

Activity Patterns during Food Provisioning Are Affected by Artificial Light in Free Living Great Tits (Parus major)  

Microsoft Academic Search

Artificial light may have severe ecological consequences but there is limited experimental work to assess these consequences. We carried out an experimental study on a wild population of great tits (Parus major) to assess the impact of light pollution on daily activity patterns during the chick provisioning period. Pairs that were provided with a small light outside their nest box

Mieke Titulaer; Kamiel Spoelstra; Cynthia Y. M. J. G. Lange; Marcel E. Visser

2012-01-01

342

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

343

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

344

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

NASA Astrophysics Data System (ADS)

Effects of doping of metal cations into wide band gap semiconductor photocatalysts on morphology, visible light response, and photocatalytic performance were studied. Doping of lanthanide and alkaline earth ions improved activity of a NaTaO3 photocatalyst for water splitting. Lanthanum was the most effective dopant. The NaTaO3:La with a NiO cocatalyst gave 56% of a quantum yield at 270 nm. This remarkable photocatalytic activity was brought by formations of nano-crystalline particle and surface nano-step structure by the doping. On the other hand, metal cation doping into ZnS, TiO2, and SrTiO3 gave visible light responses for H2 or O2 evolution from aqueous solutions containing of sacrificial reagents. The visible light responses were due to the electronic transition from donor levels formed with dopants to conduction bands of the host photocatalysts. Codoping was effective to compensate charge unbalance brought by doping of transition metal cations, resulting in the improvement of visible light response for photocatalytic reactions. Among the transition metal-doped photocatalysts, SrTiO3 doped with Rh (SrTiO3:Rh) was the novel metal oxide photocatalyst that produced H2 under visible light irradiation. The SrTiO3:Rh photocatalyst was employed with O2 evolution photocatalysts such as BiVO4 and WO3 for construction of Z-scheme systems that were active for water splitting into H2 and O2 under visible light irradiation.

Kudo, Akihiko; Niishiro, Ryo; Iwase, Akihide; Kato, Hideki

2007-10-01

345

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

346

Selective activation of mGluR8 receptors modulates retinal ganglion cell light responses  

PubMed Central

Extracellular and whole-cell light-evoked responses of mouse retinal ganglion cells were recorded in the presence of the mGluR8 selective agonist, (S)-3,4-dicarboxy-phenylglycine (DCPG). Off-light responses were reversibly reduced in the presence of DCPG in wild-type but not in mGluR8-deficient retinas. On-responses were only marginally modulated by DCPG. During Off-responses, DCPG suppressed both excitatory and inhibitory synaptic conductances suggesting that mGluR8 receptor activity reduces glutamate release from bipolar cell terminals and possibly also the release of an inhibitory neurotransmitter from amacrine cell processes.

Quraishi, S.; Reed, B. T.; Duvoisin, R. M.; Taylor, W. R.

2010-01-01

347

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

PubMed

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

Polstein, Lauren R; Gersbach, Charles A

2012-09-27

348

Photochemotherapy of intimal hyperplasia using Psoralen activated by uv light in porcine model  

NASA Astrophysics Data System (ADS)

Psoralen activated by UVA light (PUVA) was investigated as a means of inhibiting smooth muscle cell proliferation resulting from balloon injury. Twenty kilogram domestic swine were anesthetized and underwent balloon angioplasty to create a 133% overstretch injury. Assignments of treatment and control were randomized between the left anterior descending (LAD) and circumflex (LCX) coronaries arteries. The animals were given with 5 mg/kg of 8- methoxypsoralen eternally. Treatment vessels received 600 mJ/cm2 of 364 nm light during balloon inflation to activate the psoralen. Control vessels received drug and balloon injury only. Serum was obtained during the light delivery to assess psoralen levels. At 30 days, animals were sacrificed and the coronary arteries perfusion fixed. Five sections per vessel were analyzed morphometrically to determine percent intimal area and extent of injury. The restenosis injury index was 0.21 plus or minus .02 in treatment vessels and 0.14 plus or minus .01 in the controls with a p-value less than .02. In this large animal model of balloon angioplasty injury, psoralen activated by ultraviolet light increased intimal hyperplasia.

Buckley, Lisa A.; Gregory, Kenton W.; Bahlman, Deborah T.; Shangguan, Hanqun; Fahrenbach, Henner; Rosenthal, Eli; Block, Peter C.

1996-05-01

349

Human Cryptochrome-1 Confers Light Independent Biological Activity in Transgenic Drosophila Correlated with Flavin Radical Stability  

PubMed Central

Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome - 1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism.

Vieira, Jacqueline; Jones, Alex R.; Danon, Antoine; Sakuma, Michiyo; Hoang, Nathalie; Robles, David; Tait, Shirley; Heyes, Derren J.; Picot, Marie; Yoshii, Taishi; Helfrich-Forster, Charlotte; Soubigou, Guillaume; Coppee, Jean-Yves; Klarsfeld, Andre; Rouyer, Francois; Scrutton, Nigel S.; Ahmad, Margaret

2012-01-01

350

Human cryptochrome-1 confers light independent biological activity in transgenic Drosophila correlated with flavin radical stability.  

PubMed

Cryptochromes are conserved flavoprotein receptors found throughout the biological kingdom with diversified roles in plant development and entrainment of the circadian clock in animals. Light perception is proposed to occur through flavin radical formation that correlates with biological activity in vivo in both plants and Drosophila. By contrast, mammalian (Type II) cryptochromes regulate the circadian clock independently of light, raising the fundamental question of whether mammalian cryptochromes have evolved entirely distinct signaling mechanisms. Here we show by developmental and transcriptome analysis that Homo sapiens cryptochrome--1 (HsCRY1) confers biological activity in transgenic expressing Drosophila in darkness, that can in some cases be further stimulated by light. In contrast to all other cryptochromes, purified recombinant HsCRY1 protein was stably isolated in the anionic radical flavin state, containing only a small proportion of oxidized flavin which could be reduced by illumination. We conclude that animal Type I and Type II cryptochromes may both have signaling mechanisms involving formation of a flavin radical signaling state, and that light independent activity of Type II cryptochromes is a consequence of dark accumulation of this redox form in vivo rather than of a fundamental difference in signaling mechanism. PMID:22427812

Vieira, Jacqueline; Jones, Alex R; Danon, Antoine; Sakuma, Michiyo; Hoang, Nathalie; Robles, David; Tait, Shirley; Heyes, Derren J; Picot, Marie; Yoshii, Taishi; Helfrich-Förster, Charlotte; Soubigou, Guillaume; Coppee, Jean-Yves; Klarsfeld, André; Rouyer, Francois; Scrutton, Nigel S; Ahmad, Margaret

2012-03-12

351

Numerical simulation of transient hydroelastic response of a floating beam induced by landing loads  

Microsoft Academic Search

The dynamic response of a floating platform under the effects of impulsive and moving loads is of concern in various areas of engineering technology, such as floating airports, floating bridges and buoyant tunnels, among others. In the present work, the floating platform is simplified as a flexible beam floating in an infinite water domain. The water is assumed to be

Liu-chao Qiu

2007-01-01

352

GIS spatial analysis of floating population in Wenzhou, China: Implications for industrial restructuring  

Microsoft Academic Search

The paper analyses the spatial distribution of floating population in Wenzhou urban districts using the data gained from the fifth census (2000) and floating population statistics (2008). The floating population in Wenzhou urban districts clustered in geographic space and is three circling structure. More floating population settled in suburb in 2000, and the high clustering circle of floating population has

Jianguang Xu

2011-01-01

353

Preparation and characterization of visible-light-active nitrogen-doped TiO2 photocatalyst.  

PubMed

A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO4)2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence (XRF) shows that doped-nitrogen was presented in the sample. The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400 degrees C to 700 degrees C under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation. PMID:16158579

Huang, Xian-Huai; Tang, Yu-Chao; Hu, Chun; Yu, Han-Qing; Chen, Chu-Sheng

2005-01-01

354

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

SciTech Connect

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

Jan Talbot; Kailash Mishra

2007-12-31

355

Manipulating cell migration and proliferation with a light-activated polypeptide.  

PubMed

Remote control of cells: A polypeptide has been made that stimulates proliferation and migration of cells upon photochemical activation. This light-activated polypeptide enables spatially defined control of cell populations at the scale of tissue organization; this is accomplished without physically contacting the cells or modifying their substrate. Polypeptide growth and differentiation factors modulate a wide variety of cell behaviors and can be used to manipulate cells in vitro for tissue engineering and basic studies of cell biology. To emulate in vitro the spatial aspect of growth factor function, new methods are needed to generate defined spatial gradients of activity. Polypeptide factors that are engineered to be activated with light provide a method for creating concentration gradients with the fine precision in space and time with which light can be directed. As a first test of this approach, we have chemically synthesized a polypeptide with the sequence of epidermal growth factor in which a critical glutamate is "caged" with a photoremovable group. Photolysis of this polypeptide afforded maximal mitogenic and chemokinetic activity at concentrations at which the caged factor was inactive. Spatially resolved photolysis of the factor resulted in spatial patterning of fibroblasts. This system will be useful for ex vivo tissue engineering and for investigating the interactions of cells with their matrix and the role of chemical gradients in biological pattern formation. PMID:19165838

Miller, Danielle S; Chirayil, Sara; Ball, Haydn L; Luebke, Kevin J

2009-02-13

356

Redox and Light Control the Heme-Sensing Activity of AppA.  

PubMed

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. IMPORTANCE Photosynthetic bacteria must coordinate synthesis of the tetrapyrroles cobalamin, heme, and bacteriochlorophyll, as overproduction of the latter two is toxic to cells. A key regulator controlling tetrapyrrole biosynthesis is PpsR, and the activity of PpsR is controlled by the heme-binding and light-regulated antirepressor AppA. We show that AppA binds heme only under dark conditions and that heme binding significantly affects the length of the AppA photocycle. Since AppA interacts with PpsR only in the dark, bound heme thus stimulates the antirepressor activity of PpsR. This causes the redirection of tetrapyrrole biosynthesis away from heme into the bacteriochlorophyll branch. PMID:23982072

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

2013-08-27

357

Low-Voltage, Low-Power, Organic Light-Emitting Transistors for Active Matrix Displays  

NASA Astrophysics Data System (ADS)

Intrinsic nonuniformity in the polycrystalline-silicon backplane transistors of active matrix organic light-emitting diode displays severely limits display size. Organic semiconductors might provide an alternative, but their mobility remains too low to be useful in the conventional thin-film transistor design. Here we demonstrate an organic channel light-emitting transistor operating at low voltage, with low power dissipation, and high aperture ratio, in the three primary colors. The high level of performance is enabled by a single-wall carbon nanotube network source electrode that permits integration of the drive transistor and the light emitter into an efficient single stacked device. The performance demonstrated is comparable to that of polycrystalline-silicon backplane transistor-driven display pixels.

McCarthy, M. A.; Liu, B.; Donoghue, E. P.; Kravchenko, I.; Kim, D. Y.; So, F.; Rinzler, A. G.

2011-04-01

358

On a comprehensive case for Managed Floating in Thailand: How much “managed” and how much “floating”?  

Microsoft Academic Search

This paper searches for an appropriate exchange rate regime and provide a broad guideline for exchange rate management for Thailand in the medium term. An appropriate exchange rate regime is defined to be a credible regime that is most desirable. Our findings are in agreement with the flexible exchange rate view, but not freely floating. Flexible exchange rate is associated

Ashvin Ahuja

2004-01-01

359

Research effort aims at floating production technology  

SciTech Connect

This paper reports that a 3 year research and development program on floating production systems (FPS), instigated by the Royal Norwegian Council for Scientific and Industrial Research (NTNF), has refined and qualified technologies for North Sea and arctic conditions. The FPS 2000 program, which cost 58 million kroner ($10 million), concentrated mainly on mooring systems and pipeline technology, along with new system concepts and cost reduction measures. More than 30 projects have been completed within the scheme. The anchoring and positioning project concentrates on developing methods for simulating behavior of mooring systems for large volume structures in deep water. It also seeks ways to determine efficiency of dynamic positioning thrusters under extreme conditions.

Not Available

1992-08-17

360

Localized buckling of a floating elastica  

NASA Astrophysics Data System (ADS)

We study the buckling of a two-dimensional elastica floating on a bath of dense fluid, subjected to axial compression. The sinusoidal pattern predicted by the analysis of linear stability is shown to become localized above the buckling threshold. A nonlinear amplitude equation is derived for the envelope of the pattern. These results provide a simple interpretation to the wrinkle-to-fold transition reported by Pocivavsek [ScienceSCIEAS0036-807510.1126/science.1154069 320, 912 (2008)]. An analogy with the classical problem of the localized buckling of a strut on a nonlinear elastic foundation is presented.

Audoly, B.

2011-07-01

361

Effects of sodium nitrite on ultraviolet light-induced relaxation and ultraviolet light-dependent activation of guanylate cyclase in bovine mesenteric arteries  

SciTech Connect

It was demonstrated that precontracted strips from different bovine mesenteric arteries showed variation in sensitivity to ultraviolet radiation (366 nm). Some strips relaxed when they were exposed to ultraviolet light, others showed no sensitivity at all and, finally, some showed contraction. However, all arteries relaxed when they were irradiated with UV-light in the presence of 10 microM NaNO{sub 2}. Ultraviolet radiation (366 nm) increased the activity of guanylate cyclase in crude homogenate from bovine mesenteric arteries by about 20-fold in the presence of NaNO{sub 2}, while UV-light in the absence of sodium nitrite had no effect on the guanylate cyclase activation. These results support the notion that nitrite may be essential for vascular smooth muscle relaxation by UV-light, possibly through the release of nitric oxide.

Wigilius, I.M.; Axelsson, K.L.; Andersson, R.G.; Karlsson, J.O.; Odman, S. (Linkoeping Univ. (Sweden))

1990-05-31

362

Recovery of photosystem II activity in photoinhibited synechocystis cells: light-dependent translation activity is required besides light-independent synthesis of the D1 protein.  

PubMed

Irreversible photoinactivation of photosystem II (PSII) results in the degradation of the reaction center II D1 protein. In Synechocystis PCC 6714 cells, recovery of PSII activity requires illumination. The rates of photoinactivation and recovery of PSII activity in the light are similar in cells grown in minimal (MM) or glucose-containing medium (GM). Reassembly of PSII with newly synthesized proteins requires degradation of the D1 protein of the photoinactivated PSII. This process may occur in darkness in both types of cells. The degraded D1 protein is, however, only partially replaced by newly synthesized protein in MM cells in darkness while a high level of D1 protein synthesis occurs in darkness in the GM cells. The newly synthesized D1 protein in darkness appears to be assembled with other PSII proteins. However, PSII activity is not recovered in such cells. Illumination of the cells in absence but not in the presence of protein synthesis inhibitors allows recovery of PSII activity. PMID:10684653

Constant, S; Eisenberg-Domovitch, Y; Ohad, I; Kirilovsky, D

2000-02-29

363

Preparation and enhanced visible-light photocatalytic activity of graphitic carbon nitride/bismuth niobate heterojunctions.  

PubMed

A series of graphitic carbon nitride/bismuth niobate (g-C3N4/Bi5Nb3O15) heterojunctions with g-C3N4 doping level of 10-90wt% were prepared by a facile milling-heat treatment method. The phase and chemical structures, surface compositions, electronic and optical properties as well as morphologies of the prepared g-C3N4/Bi5Nb3O15 were well-characterized. Subsequently, the photocatalytic activity and stability of g-C3N4/Bi5Nb3O15 were evaluated by the degradation of aqueous methyl orange (MO) and 4-chlorophenol (4-CP) under the visible-light irradiation. At suitable g-C3N4 doping levels, g-C3N4/Bi5Nb3O15 exhibited enhanced visible-light photocatalytic activity compared with pure g-C3N4 or Bi5Nb3O15. This excellent photocatalytic activity was revealed in terms of the extension of visible-light response and efficient separation and transportation of the photogenerated electrons and holes due to coupling of g-C3N4 and Bi5Nb3O15. Additionally, the active species yielded in the pure g-C3N4- and g-C3N4/Bi5Nb3O15-catalyzed 4-CP photodegradation systems were investigated by the free radical and hole scavenging experiments. PMID:23933291

Zhang, Shengqu; Yang, Yuxin; Guo, Yingna; Guo, Wan; Wang, Mei; Guo, Yihang; Huo, Mingxin

2013-07-22

364

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

365

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

366

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

PubMed

High sensitivity photodetectors in ultraviolet (UV) and infrared (IR) range have broad civilian and military applications. Here we report on an un-cooled solution-processed UV-IR photon counter based on modified organic field-effect transistors. This type of UV detectors have light absorbing zinc oxide nanoparticles (NPs) sandwiched between two gate dielectric layers as a floating gate. The photon-generated charges on the floating gate cause high resistance regions in the transistor channel and tune the source-drain output current. This "super-float-gating" mechanism enables very high sensitivity photodetectors with a minimum detectable ultraviolet light intensity of 2.6?photons/?m(2)s at room temperature as well as photon counting capability. Based on same mechansim, infrared photodetectors with lead sulfide NPs as light absorbing materials have also been demonstrated. PMID:24048259

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

2013-09-19

367

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

PubMed Central

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

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

2013-01-01

368

Floating recycle pan and process for ebullated bed reactors  

SciTech Connect

This patent describes a hydrotreating process, comprising the steps of: feeding a hydrotreating catalyst into an ebullated bed reactor; partially filling the ebullated bed reactor to a level defining a liquid level below the top of the reactor with a feed comprising oil and hydrogen-rich gases; raising the level of the feed by activating an ebullating pump and concurrently ebullating, contacting, and mixing the feed with the catalysts; floating a tubular pan upon the feed partially below the level in the reactor and at least partially above a downcomer to allow the pan to rise in response to the rising of the liquid level for facilitating flow of the feed to the downcomer; directing the feed substantially downwardly through the pan and the downcomer in the ebullated bed reactor; and mixing and contacting the oil and the hydrogen-rich gases with the catalyst to produce hydrotreated oil.

Cox, J.A.

1988-12-20

369

Weather-induced changes in moth activity bias measurement of long-term population dynamics from light trap samples  

Microsoft Academic Search

Interpretation of light trap catches of moths is complicated by daily variation in weather that alters flight activity and numbers caught. Light trap efficiency is also modified by wind and fog, and daily weather may effect absolute abundance (numbers actually present). However, actograph experiments and other sampling methods suggest that changes in daily activity are large by comparison to changes

M. Holyoak; V. Jarosik; I. Novak

1997-01-01

370

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

371

40 CFR 65.43 - Fixed roof with an internal floating roof (IFR).  

Code of Federal Regulations, 2013 CFR

...cover or gasketed lid. (iii) Each penetration of the internal floating roof shall...vent shall be gasketed. (v) Each penetration of the internal floating roof that allows...gasketed sliding cover. (vi) Each penetration of the internal floating roof...

2013-07-01

372

Superhydrophilicity-assisted preparation of transparent and visible light activated N-doped titania film  

NASA Astrophysics Data System (ADS)

A novel and environmental friendly method was developed to prepare transparent, uniform, crack-free and visible light activated nitrogen doped (N-doped) titania thin films without the use of organic Ti precursors and organic solvents. The N-doped titania films were prepared from heating aqueous peroxotitanate thin films deposited uniformly on superhydrophilic uncoated glass substrates. The pure glass substrates were superhydrophilic after being heated at 500 °C for 1 h. Nitrogen concentrations in the titania films were adjusted by changing the amount of ammonia solution. The optimal photocatalytic activity of the N-doped titania films was about 14 times higher than that of a commercial self-cleaning glass under the same visible light illumination. The current reported preparative technique is generally applicable for the preparation of other thin films.

Xu, Qing Chi; Wellia, Diana V.; Amal, Rose; Liao, Dai Wei; Loo, Say Chye Joachim; Tan, Timothy Thatt Yang

2010-07-01

373

Preparation and characterization of porous C-modified anatase titania films with visible light catalytic activity  

NASA Astrophysics Data System (ADS)

Visible-light-activated C-modified anatase titania films have been synthesized from TiCl4 and carbonic ink by using the sol gel route. The synthesized photocatalysts were characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and optical measurements. The modifying carbon not only produces homogeneous worm-like structure with uniform pores, but also extends the absorbance spectra of the as-prepared films into visible region. The results of visible-light-induced degradation of methyl orange (MO) show that the C-modified titania films exhibits much higher photocatalytic activities than that of pure titania film prepared at the same conditions.

Xie, Yi; Zhao, Xiujian; Chen, Yunxia; Zhao, Qingnan; Yuan, Qihua

2007-12-01

374

Light scattering from an optically active sphere into a circular aperture.  

PubMed

To show how apertures affect measurements of the circularly polarized components of light scattered to a detector, we develop two methods of averaging the V and I Stokes parameters over a circular aperture that collects light scattered from an optically active sphere. One method uses a two-dimensional numerical integration that is appropriate for small apertures, and the other gives analytical expressions for scattering into a solid angle of any size. We identify the aperture locations that, independent of aperture size, give an average V (and an effective degree of circular polarization) of zero for scattering from an optically inactive sphere and of nonzero for scattering from an optically active sphere. PMID:18301631

Pendleton, J D; Rosen, D L

1998-11-20

375

Floating treatment wetlands for domestic wastewater treatment.  

PubMed

Floating islands are a form of treatment wetland characterized by a mat of synthetic matrix at the water surface into which macrophytes can be planted and through which water passes. We evaluated two matrix materials for treating domestic wastewater, recycled plastic and recycled carpet fibers, for chemical oxygen demand (COD) and nitrogen removal. These materials were compared to pea gravel or open water (control). Experiments were conducted in laboratory scale columns fed with synthetic wastewater containing COD, organic and inorganic nitrogen, and mineral salts. Columns were unplanted, naturally inoculated, and operated in batch mode with continuous recirculation and aeration. COD was efficiently removed in all systems examined (>90% removal). Ammonia was efficiently removed by nitrification. Removal of total dissolved N was ?50% by day 28, by which time most remaining nitrogen was present as NO(3)-N. Complete removal of NO(3)-N by denitrification was accomplished by dosing columns with molasses. Microbial communities of interest were visualized with denaturing gradient gel electrophoresis (DGGE) by targeting specific functional genes. Shifts in the denitrifying community were observed post-molasses addition, when nitrate levels decreased. The conditioning time for reliable nitrification was determined to be approximately three months. These results suggest that floating treatment wetlands are a viable alternative for domestic wastewater treatment. PMID:22105133

Faulwetter, J L; Burr, M D; Cunningham, A B; Stewart, F M; Camper, A K; Stein, O R

2011-01-01

376

Floating bodies in two dimensions without gravity  

NASA Astrophysics Data System (ADS)

In this paper we study the stability of equilibrium configurations for two-dimensional smooth convex bodies in the absence of gravity, focusing on one example in particular, the ellipse. We also begin to consider the floating configurations of bodies which are not strictly convex; that is, bodies that have one or more linear sides. We will show that a body cannot float in a stable equilibrium with the fluid interface intersecting the interior of a straight side in a single point, and then using this result we will proceed to study the stability of convex bodies comprised of only straight sides consequently deriving a necessary and sufficient condition for stable equilibrium of polygonal bodies. We illustrate our findings using the square as an example. Finally, we prove several results concerning the number of stable and unstable configurations for an n-sided regular polygon (n>=3) including a result guaranteeing the existence of a stable global energy minimum provided the contact angle ? is not 0 or ?.

Kemp, Todd M.; Siegel, David

2011-04-01

377

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

378

Flame sprayed visible light-active Fe-TiO 2 for photomineralisation of oxalic acid  

Microsoft Academic Search

Visible light-active Fe-doped TiO2 was prepared by a one-step flame spray pyrolysis (FSP) technique. The properties of the photocatalysts were characterised by UV–vis diffuse-reflectance spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption (BET), transmission electron microscope (TEM) and zeta potential techniques. Being a bottom-up approach, the short residence time coupled with rapid quenching during FSP resulted in homogeneous

Wey Yang Teoh; Rose Amal; Lutz Mädler; Sotiris E. Pratsinis

2007-01-01

379

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

380

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

Microsoft Academic Search

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

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

1995-01-01

381

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

Microsoft Academic Search

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

Wolfgang Buchalla; Thomas Attin

2007-01-01

382

Light activation of the immune system part I: influence on G-class antibodies  

NASA Astrophysics Data System (ADS)

The experimental evidences for photochemical mechanism of light activation of immune system are presented. The experiments were made in vitro using serums from normal blood, from blood of people with secondary immunodeficiency containing low-avidity IgG (up to 75 - 90%), and pure IgG buffer solutions obtained from the same serums. LED arrays and halogen lamps with narrow spectral filters from UV to IR were used as optical monochromatic sources. We have discovered that light can activate immune system by IgG transformation from low-avidity state to high-avidity one. This change has multistage irreversible character and depends on light wavelength and intensity. The estimations of optical effects were made by determination of IgG functional activity and quaternary antibody structure through the number of accessible functional protein residues in the IgG buffer solutions. Both methods showed very correlated results. Each IgG avidity transformation stage correlated with definite change of antibody spatial structure that, to our opinion, corresponds to the phenomenon pass through the several intermediate metastable forms, which are maintained by different intermolecular bonds. The bioaction spectrum of discovered effects is also presented.

Zharov, Vladimir P.; Gevondyan, Vladimir S.; Gevondyan, Natalya M.; Ermilov, Sergey A.; Volynskaya, Alla M.

2000-06-01

383

The effect of power bleaching actived by several light sources on enamel microhardness  

NASA Astrophysics Data System (ADS)

The purpose of this study was to evaluate the influence of different light sources for in-office bleaching on surface microhardness of human enamel. One hundred and five blocks of third molars were distributed among seven groups. The facial enamel surface of each block was polished and baseline Knoop microhardness of enamel was assessed with a load of 25 g for 5 s. Subsequently, the enamel was treated with 35% hydrogen peroxide bleaching agent and photo-activated with halogen light (group A) during 38 s, LED (group B) during 360 s, and high intensity diode laser (group C) during 4 s. The groups D (38 s), E (360 s), and F (4 s) were treated with the bleaching agent without photo-activated. The control (group G) was only kept in saliva without any treatment. Microhardness was reassessed after 1 day of the bleaching treatment, and after 7 and 21 days storage in artificial saliva. The mean percentage and standard deviation of microhardness in Knoop Hardness Number were: A 97.8 ± 13.1 KHN; B 95.5 ± 12.7 KHN; C 84.2 ± 13.6 KHN; D 128.6 ± 20.5 KHN; E 133.9 ± 14.2 KHN; F 123.9 ± 14.2 KHN; G 129.8 ± 18.8 KHN. Statistical analysis ( p < 0.05; Tukey test) showed that microhardness percentage values were significantly lower in the groups irradiated with light when compared with the non-irradiated groups. Furthermore, the non-irradiated groups showed that saliva was able to enhance the microhardness during the measurement times. The enamel microhardness was decreased when light sources were used during the bleaching process and the artificial saliva was able to increase microhardness when no light was used.

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

2010-07-01

384

Defining the IEEE-854 Floating-Point Standard in PVS.  

National Technical Information Service (NTIS)

A significant portion of the ANSI/IEEE-854 Standard for Radix-Independent Floating-Point Arithmetic is defined in PVS (Prototype Verification System). Since IEEE-854 is a generalization of the ANSI/IEEE-754 Standard for Binary Floating-Point Arithmetic, t...

P. S. Miner

1995-01-01

385

33 CFR 144.01-15 - Alternates for life floats.  

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Alternates for life floats. 144.01-15 Section 144.01-15...Platforms § 144.01-15 Alternates for life floats. (a) Approved lifeboats, approved life rafts or approved inflatable life rafts...

2013-07-01

386

Maximum size of floating particles in different flotation cells  

Microsoft Academic Search

Two flotation models, particle at the liquid–gas interface and particle–bubble aggregate, both based on balance of forces, were used for evaluation of experimental data relating the maximum size of floating particles dmax and their advancing contact angle. It was noticed, by comparing the experimental and model data, that for a given flotation device and material the maximum size of floating

Przemyslaw B. Kowalczuk; Oktay Sahbaz; Jan Drzymala

2011-01-01

387

22. Float located adjacent to entry stair in filtration bed. ...  

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

22. Float located adjacent to entry stair in filtration bed. The float actuates a valve that maintains water level over the bed. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

388

Hydroelastic behaviour of compound floating plate in waves  

Microsoft Academic Search

The paper deals with the plane problem of the hydroelastic behaviour of floating plates under the influence of periodic surface water waves. Analysis of this problem is based on hydroelasticity, in which the coupled hydrodynamics and structural dynamics problems are solved simultaneously. The plate is modeled by an Euler beam. The method of numerical solution of the floating-beam problem is

T. I. Khabakhpasheva; A. A. Korobkin

2002-01-01

389

Surface characterization of float glass using Indus1  

Microsoft Academic Search

The production of window glass is through float technique, which causes diffusion of tin into glass surface in contact with molten tin. Using Indus-1 storage ring, angle dependent reflectivity of the top and the bottom surface of float glass were measured in vacuum ultra violet\\/ soft x-ray region. Remarkable differences in refractive index were observed between the two sides. Surface

G. S. Lodha; M. K. Tiwari; K. J. S. Sawhney; M. H. Modi; R. V. Nandedkar

390

Dynamic Characteristics of a Floating Squeeze Film Bearing.  

National Technical Information Service (NTIS)

A floating squeeze film bearing is a flexible support system used to attenuate the forces generated by a rotating unbalanced shaft. Since the journal translates instead of rotating, a floating squeeze film bearing develops twice the load of an ordinary jo...

G. C. Horner

1968-01-01

391

Dynamic characteristics of a floating squeeze film bearing  

Microsoft Academic Search

A floating squeeze film bearing is a flexible support system used to attenuate the forces generated by a rotating unbalanced shaft. Since the journal translates instead of rotating, a floating squeeze film bearing develops twice the load of an ordinary journal bearing. Hydrodynamic forces are generated in the fluid film of the squeeze film bearing which counteract the unbalanced force.

1968-01-01

392

Coupled Dynamic Modeling of Floating Wind Turbine Systems: Preprint  

Microsoft Academic Search

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

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

2006-01-01

393

Surface functionalisation of polypyrrole films using UV light induced radical activation  

NASA Astrophysics Data System (ADS)

Electrochemically deposited polypyrrole (PPy) films were functionalised with amine or carboxylic function. The functionalisation was done by grafting allylamine or acrylic acid (AAc) using UV light radical activation. The active groups of the surface were quantified by X-ray photoelectron spectroscopy (XPS) after chemical derivatisation with trifluoroethanol (TFE) or 4-trifluoromethylbenzaldehyde (TFBA), respectively. Grafting with AAc completely covered the PPy film introducing high levels of carboxylic function. In the case of allylamine grafting, a saturation point at low amine carbon level was achieved. Further characterisation of the surfaces was done by time of flight secondary ion mass spectroscopy (TOF-SIMS), atomic force microscope (AFM) and scanning electron microscope (SEM).

Lisboa, P.; Gilliland, D.; Ceccone, G.; Valsesia, A.; Rossi, F.

2006-04-01

394

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

NASA Astrophysics Data System (ADS)

The present study deals with the synthesis of highly uniform and spherical visible-light-driven colloidal silver phosphate (Ag3PO4) with the size of ˜200 nm. These colloidal particles showed excellent photocatalytic activity for the removal of different dyes and pesticide under sunlight-type excitation. The photocatalytic activity of these particles, obtained by colloidal method, was found to be much higher than silver phosphate obtained by precipitation method, or titanium dioxide, or zinc oxide under identical conditions. The effect of catalyst amount and recyclability on the photocatalytic response of Ag3PO4 was also investigated.

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

2012-01-01

395

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

PubMed

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

Suzuki, Takaaki; Yoshinaga, Naoko

2012-07-31

396

Effect of a floating electrode on a plasma jet  

NASA Astrophysics Data System (ADS)

Two kinds of floating electrode, floating dielectric barrier covered electrode (FDBCE) and floating pin electrode (FPE), which can enhance the performance of plasma jet are reported. The intense discharge between the floating electrode and power electrode decreased the voltage to trigger the plasma jet substantially. The transition of plasma bullet from ring shape to disk shape in the high helium concentration region happened when the floating electrode was totally inside the powered ring electrode. The enhanced electric field between propagating plasma bullet and ground electrode is the reason for this transition. The double plasma bullets happened when part of the FDBCE was outside the powered ring electrode, which is attributed to the structure and surface charge of FDBCE. As part of the FPE was outside the powered ring electrode, the return stroke resulted in a single intensified plasma channel between FPE and ground electrode.

Hu, J. T.; Wang, J. G.; Liu, X. Y.; Liu, D. W.; Lu, X. P.; Shi, J. J.; Ostrikov, K.

2013-08-01

397

The implementation of an out-of-order execution floating point unit  

Microsoft Academic Search

The prRISC32 FPU (floating-point unit) is a RISC coprocessor for embedded system applications. It supports IEEE754 standard single\\/double precision floating-point addition, floating-point subtraction, floating-point multiplication, floating-point division, floating-point square root, floating-point\\/fix-point format conversion, and floating point load\\/store, etc. It also supports four IEEE compliant rounding mode, and precise exception. It can execute and complete instructions out of order under certain

Luo Min; Bai Yong-Qiang; Shen Xu-Bang; Gao De-Yuan

2004-01-01

398

Cosignaling molecules around LIGHT-HVEM-BTLA: from immune activation to therapeutic targeting.  

PubMed

The regulation of the immune system at the cell surface is primarily controlled by two families of cosigaling molecules: the immunoglobulin (Ig) superfamily, or "CD28 and B7 family", and the tumor necrosis factor receptor (TNFR) family. Here, we summarized the principal structural and functional characteristics of both families. In this respect, the interaction between HVEM, a TNF receptor, and BTLA, an Ig family member, has provided a new perspective and an additional level of complexity in the crosstalk between these two regulatory systems. This review will present a summary of the recent advances in the immunobiology of the LIGHT-HVEM-LTbetaR-BTLA network. The LIGHT-HVEM-BTLA system has emerged as a major regulator of immune responses and lymphocyte activation, whereas LIGHT-LTbetaR participates in lymphoid tissue development and cell death. Moreover, recent studies have provided encouraging new insights into the roles of the LIGHT-HVEM-LTbetaR-BTLA axis as a potential target for controlling anti-tumor responses. PMID:19860669

Pasero, Christine; Truneh, Alemseged; Olive, Daniel

2009-09-01

399

Conjugated polymer nanoparticles for light-activated anticancer and antibacterial activity with imaging capability.  

PubMed

A new water-soluble conjugated polymer containing fluorene and boron-dipyrromethene repeat units in the backbones (PBF) that exhibits red emission was synthesized and characterized. Cationic PBF forms uniform nanoparticles with negatively charged disodium salt 3,3'-dithiodipropionic acid (SDPA) in aqueous solution through electrostatic interactions. The nanoparticles display absorption maximum at 550 nm and emission maximum at 590 nm. Upon photoexcitation with white light (400-800 nm) with 90 and 45 mW·cm(-2) for bacteria and cancer cells killing respectively, PBF nanoparticles can sensitize the oxygen molecule to readily produce reactive oxygen species (ROS) for rapidly killing neighboring bacteria and cancer cells. Furthermore, PBF nanoparticles concurrently provide optical imaging capability. PBF nanoparticles are therefore a promising multifunctional material for treating cancers and bacteria infections, while concurrently providing optical monitoring capabilities. PMID:22054172

Chong, Hui; Nie, Chenyao; Zhu, Chunlei; Yang, Qiong; Liu, Libing; Lv, Fengting; Wang, Shu

2011-11-17

400

Study of a light-gas gun for launching active transient internal probes  

NASA Astrophysics Data System (ADS)

The Transient Internal Probe (TIP) is a diagnostic for the measurements of local parameters in high temperature plasmas. An optic probe is launched into a plasma at ˜1.8 km/s using a two-stage light gas gun, while a polarized laser light illuminates the probe and the light retroreflected after double-pass through the probe is continuously detected with an ellipsometer. The polarization state change of the light corresponds to Faraday rotation or Pockels effect depending on the probe material. Recently developed refractory clad probes and catseye retroreflecting probes are presented in this paper. One component of magnetic field or electric field profile measurements along the transit of the probe can be achieved by using the present passive optic probes. The next step of the TIP will be active probes utilizing on-board sensors and telemetry, which will allow measurements of multiple plasma parameters, possibly including the plasma temperature and density. At issue is the survivability of the on-board electronic components under the high acceleration during launch. Experimental and numerical study of the TIP light gas gun has been performed to lower the maximum acceleration of the probe while the probe velocity is still high (?1.5 km/s) to avoid ablation during transit through a plasma. A microwave cavity technique is used to measure the probe position versus time during launch, from which the in-bore velocity and the acceleration profiles are determined. Piezoelectric pressure sensors measure the pressure history of the gun gas at several locations. A numerical code ('SIMTIP') is used to simulate the TIP two-stage light gas gun and the code output is compared to the measurements. This paper provides an optimum gun operation condition for launching an on-board active TIP. A prototype of the active TIP has been gun-launched. The probe includes a timer, a capacitor, and a Vertical Cavity Surface Emitting Laser (VCSEL). It survived ?160,000 g's of acceleration and achieved a velocity of 1,700 m/s.

Kim, Hyundae

401

Light-evoked synaptic activity of retinal ganglion and amacrine cells is regulated in developing mouse retina  

PubMed Central

Recent studies have shown a continued maturation of visual responsiveness and synaptic activity of retina after eye opening, including the size of receptive fields of retinal ganglion cells (RGCs), light-evoked synaptic output of RGCs, bipolar cell spontaneous synaptic inputs to RGCs, and the synaptic connections between RGCs and ON and OFF bipolar cells. Light deprivation retarded some of these age-dependent changes. However, many other functional and morphological features of RGCs are not sensitive to visual experience. To determine whether light-evoked synaptic responses of RGCs undergo developmental change, we directly examined the light-evoked synaptic inputs from ON and OFF synaptic pathways to RGCs in developing retinas and found that both light-evoked excitatory and inhibitory synaptic currents decreased, but not increased, with age. We also examined the light-evoked synaptic inputs from ON and OFF synaptic pathways to amacrine cells in developing retinas and found that the light-evoked synaptic input of amacrine cells is also down-regulated in developing mouse retina. Different from the developmental changes of RGC spontaneous synaptic activity, dark rearing has little effect on the developmental changes of light-evoked synaptic activity of both RGCs and amacrine cells. Therefore, we concluded that the synaptic mechanisms mediating spontaneous and light-evoked synaptic activity of RGCs and amacrine cells are likely to be different.

He, Quanhua; Wang, Ping; Tian, Ning

2010-01-01

402

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

PubMed

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. PMID:23288415

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

403

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

404

The activation of directional stem cell motility by green light-emitting diode irradiation.  

PubMed

Light-emitting diode (LED) irradiation is potentially a photostimulator to manipulate cell behavior by opsin-triggered phototransduction and thermal energy supply in living cells. Directional stem cell motility is critical for the efficiency and specificity of stem cells in tissue repair. We explored that green LED (530 nm) irradiation directed the human orbital fat stem cells (OFSCs) to migrate away from the LED light source through activation of extracellular signal-regulated kinases (ERK)/MAP kinase/p38 signaling pathway. ERK inhibitor selectively abrogated light-driven OFSC migration. Phosphorylation of these kinases as well as green LED irradiation-induced cell migration was facilitated by increasing adenosine triphosphate (ATP) production in OFSCs after green LED exposure, and which was thermal stress-independent mechanism. OFSCs, which are multi-potent mesenchymal stem cells isolated from human orbital fat tissue, constitutionally express three opsins, i.e. retinal pigment epithelium-derived rhodopsin homolog (RRH), encephalopsin (OPN3) and short-wave-sensitive opsin 1 (OPN1SW). However, only two non-visual opsins, i.e. RRH and OPN3, served as photoreceptors response to green LED irradiation-induced OFSC migration. In conclusion, stem cells are sensitive to green LED irradiation-induced directional cell migration through activation of ERK signaling pathway via a wavelength-dependent phototransduction. PMID:23261211

Ong, Wei-Kee; Chen, How-Foo; Tsai, Cheng-Ting; Fu, Yun-Ju; Wong, Yi-Shan; Yen, Da-Jen; Chang, Tzu-Hao; Huang, Hsien-Da; Lee, Oscar Kuang-Sheng; Chien, Shu; Ho, Jennifer Hui-Chun

2012-12-20

405

Direct modulation of activity and body temperature of owl monkeys (Aotus lemurinus griseimembra) by low light intensities.  

PubMed

The activity pattern of Aotus lemurinus griseimembra can be predictably altered by varying the illuminance during the dark phase of a 12:12-hour light:dark rhythm. Intensities well below full-moon brightness (0.1-0.5 lx) severely inhibit activity. This modulation is not the result of a light-induced phase shift of the circadian rhythm, but it is primarily caused by masking due to direct effects of light on the motor system. Both proportional and differential effects of light are involved. Miniature transmitters were implanted intraperitoneally in two Aotus females so that the core temperature could be measured in parallel with locomotor activity. The responses to brief reductions of the dark-phase illuminance, from 10(-1) to 10(-3) lx, 10(-5) lx or physiological darkness, indicate that the direct effects of light that modulate the activity of the owl monkeys also affect their temperature time-course. The influence on the temperature rhythm, unlike that on the activity rhythm, varies greatly over the circadian period. The finding that the core temperature does not always change in parallel with locomotor activity and, to some extent, reacts differently to the light:dark alternation indicates that temperature does not simply follow activity passively, but rather is partially subject to a 'direct' masking influence of the light. PMID:3609970

Erkert, H G; Gröber, J

1986-01-01

406

Secular light curve of 2P/Encke, a comet active at aphelion  

NASA Astrophysics Data System (ADS)

We present the secular light curve of Comet 2P/Encke in two phase spaces, the log plot, and the time plot. The main conclusions of this work are: (a) The comet shows activity at perihelion and aphelion, caused by two different active areas: Source 1, close to the south pole, active at perihelion, and Source 2, at the north pole, centered at aphelion. (b) More than 18 physical parameters are measured from the secular light curves, many of them new, and are listed in the individual plots of the comet. Specifically we find for Source 1 the location of the turn on and turn off points of activity, R=-1.63±0.03 AU, R=+1.49±0.20 AU, T=-87±5 d, T=+94±15 d, the time lag, LAG(q)=6±1 d, the total active time, T=181±16 d, and the amplitude of the secular light curve, A(1,1)=4.8±0.1 mag. (c) From this information the photometric age and the time-age defined in Ferrín [2005a. Icarus 178, 493-516; 2006. Icarus 185, 523-543], can be calculated, and we find P-AGE = 97 ± 8 comet years and T-AGE = 103 ± 9 comet years (cy). Thus Comet 2P/Encke is an old comet entering the methuselah stage (100 cy < age). (d) The activity at aphelion (Source 2), extends for T=815±30 d and the amplitude of the secular light curve is A(1,Q)=3.0±0.2 mag. (e) From a new phase diagram an absolute magnitude and phase coefficient for the nucleus are determined, and we find R(1,1,0)=15.05±0.14, and ?=0.066±0.003. From this data we find a nucleus effective diameter D=5.12(+2.5;-1.7) km. These values are not much different from previous determinations but exhibit smaller errors. (f) The activity of Source 1 is due to H 2O sublimation because it shows curvature. The activity of Source 2 might also be due to H 2O due to the circumstantial situation that the poles point to the Sun at perihelion and aphelion. (g) We found a photometric anomaly at aphelion, with minimum brightness between +393 and +413 days after perihelion that may be an indication of topography. (h) We have re-reduced the 1858 secular light curve of Kamel [1991. Icarus 93, 226-245]. There are secular changes in 7 physical parameters, and we achieve for the first time, an absolute age calibration. We find that the comet entered the inner Solar System and began sublimating in 1645±40 AD. (i) It is concluded that the secular light curve can place constraints on the pole orientation of the nucleus of some comets, and we measure the ecliptic longitude of the south pole of 2P/Encke equal to 213.2±4.5°, in excellent agreement with other determinations of this parameter, but with smaller error. (j) Using the observed absolute magnitude of 1858 and 2003 and a suitable theoretical model, the extinction date of the comet is determined. We obtain ED=2056±3 AD, implying that the comet's lifetime is 125±12 revolutions about the Sun after entering the inner Solar System.

Ferrín, Ignacio

2008-09-01

407

Enhanced visible light photocatalytic activity of Bi2WO6 via modification with polypyrrole  

NASA Astrophysics Data System (ADS)

Enhanced visible light photocatalytic activity of Bi2WO6 photocatalyst modified with different amounts of polypyrrole (PPy) was synthesized by 'in situ' deposition oxidative polymerization of pyrrole. The as-prepared PPy/Bi2WO6 composites were characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse absorption spectra. The photocatalytic activities of the PPy/Bi2WO6 samples were determined by photocatalytic degradation of rhodamine-B (RhB) and methylene blue (MB) in aqueous solution under visible light irradiation. The results indicated that the existence of PPy did not affect the crystal structure and the morphology of Bi2WO6 photocatalyst, but showed great influences on the photocatalytic activity of Bi2WO6. Besides, an optimal content of PPy on the surface of Bi2WO6 photocatalyst with the highest photocatalytic ability was discovered, and the obtained PPy/Bi2WO6 photocatalysts showed high stability and did not photocorrode during the photocatalytic process. The possible mechanism of enhanced photocatalytic activities of PPy/Bi2WO6 samples was also discussed in this work.

Duan, Fang; Zhang, Qianhong; Shi, Dongjian; Chen, Mingqing

2013-03-01

408

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

PubMed

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. PMID:22738162

Yu, Yuan; Zhang, Liying; Wang, Jian; Yang, Zhi; Long, Mingce; Hu, Nantao; Zhang, Yafei

2012-06-27

409

Floating-zone and floating-solution-zone growth of GaSb under microgravity  

Microsoft Academic Search

Three GaSb single crystals have been successfully grown under microgravity on Spacehab-4 during the STS-77 Space Shuttle flight. Two Te-doped crystals with 16mm diameter and lengths of 31.5 and 18mm, respectively, were grown by the floating-zone method. From the transition of striated to striation-free material it was possible to determine the critical Marangoni number for the onset of time-dependent thermocapillary

A. Cröll; Th Kaiser; M Schweizer; A. N Danilewsky; S Lauer; A Tegetmeier; K. W Benz

1998-01-01

410

Floating drilling rig apparatus and method  

SciTech Connect

This patent describes an apparatus adapted for use with a floating drilling rig having a marine riser including a telescopic joint. The telescopic joint has a guide/index key. The joint has an upwardly facing unterminated connector for a riser choke/kill line. The apparatus comprises: a terminal end assembly, including: a frame, yoke means slidably disposed on the frame for securing a drape hose terminated by a downwardly facing stab connector; means for moving the yoke means between an outer position and an inner position upon the frame; and slot means disposed on the yoke means for accepting the guide/index key of the telescopic joint when the yoke means is in the inner position.

Burton, J.A.

1987-05-26

411

Floating recycle pan for ebullated bed reactors  

SciTech Connect

This patent describes an ebullated bed reactor. It comprises: a substantially enclosed vessel having a lower portion and an upper portion for processing oil; oil feed means connected to the vessel for feeding an oil feed comprising oil and hydrogen-rich gases into the lower portion of the vessel; fresh catalyst feed means connected to the vessel for feeding fresh hydrotreating catalyst into the vessel; ebullating pump means located in the lower portion of the vessel for circulating the oil feed in the vessel in the presence of the catalyst to hydrotreat the oil; a tubular downcomer extending generally upward above the pump means. The downcomer having an upper end and, a lower end in proximity to the pump means, and an inner surface and an outer surface; and a floating tubular recycle pan.

Cox, J.A.

1990-03-27

412

Modeling and control of a floating platform  

NASA Astrophysics Data System (ADS)

A platform with a rotating crane resting on three adjustable floats in a tub has been built on laboratory scale. Controller design is studied to prevent the platform from leaning due to crane movements. The system dynamics can be described primarily by a simple sixth order linear model. Model errors are then due mainly to unmodeled effects of waves that are essentially linear transfers. It is precisely under these conditions that H(sub infinity) design should perform well. Actual design and tests show that H(sub infinity) controllers do not substantially outperform LQG designs combined with feedforward controllers, but the combination of both feedforward and feedback controllers can easily be obtained by H(sub infinity) design techniques.

Damen, Ad A. H.; Falkus, Heinz M.; Bouwels, Jo P. H. M.

1994-05-01

413

Inexpensive, floating, insect-emergence trap  

SciTech Connect

The Environmental Sciences Division of Oak Ridge National Laboratory has been investigating the usefulness of aquarium microcosms and ponds for the quantification and predictions of toxicant effects on freshwater systems. Ideally, concepts and methods applicable to both 150-L microcosms and 15,000-L ponds would bridge the gap between the two. The effort of processing the benthic samples, as well as the destructiveness of the sampling in small ponds, limited the number of samples that could be taken. Therefore, the author developed an inexpensive emergence trap appropriate for use in small outdoor ponds, as one method of increasing sampling efficiency and economy. To prevent the possibility of trapping adults from adjacent ponds, which would confound the results, the traps had to be designed such that they could only trap insects from the ponds upon which they were floating. The design of this trap is described.

Cushman, R.M.

1983-11-01

414

Light-regulation of protein dimerization and kinase activity in living cells using photocaged rapamycin and engineered FKBP  

PubMed Central

We developed a new system for light-induced protein dimerization in living cells using a novel photocaged analog of rapamycin (pRap) together with an engineered rapamycin binding domain (iFKBP). Using focal adhesion kinase as a target, we demonstrated successful light-mediated regulation of protein interaction and localization in living cells. Modification of this approach enabled light-triggered activation of a protein kinase and initiation of kinase-induced phenotypic changes in vivo.

Karginov, Andrei V.; Zou, Yan; Shirvanyants, David; Kota, Pradeep; Dokholyan, Nikolay V.; Young, Douglas D.; Hahn, Klaus M.; Deiters, Alexander

2010-01-01

415

First census of floating population in Beijing.  

PubMed

This study presents the findings of the first census of the floating population in Beijing, China, in 1997. The census was conducted in 18 urban districts and counties among migrants living or staying in Beijing with household registration elsewhere. In 1997, the floating population amounted to 2.86 million, of whom 2.30 million stayed in Beijing over 1 day. 66.1% were males; 33.9% were females. 1.38 million (59.9%) lived in institutional households. 755,000 (32.9%) formed their own family units; 166,000 (7.2%) lived with resident Beijing families. 12,000 lived in railway stations and 22,000 were homeless. In-migrants numbered 435,000 and out-migrants numbered 42,000 in the preceding 24 hours. 84,000 (a doubling since 1984) were from Hong Kong, Macao, and Taiwan. In-migration was lower by 436,000 persons than in 1994. The decline is attributed to government policy to limit migration and to economic recession. Better communication and transportation facilitate foreign migration. 1.81 million migrants out of 2.30 million lived in 4 urban and 4 suburban districts. The others lived in 10 remote suburban areas. Migrants accounted for 537,000 persons in Chaoyang District (23.3%), 493,000 in Haidan District (21.5%), and 315,000 in Fengtai District (13.7%). The ratio of in-migrants to residents was 1:8 in Beijing urban districts, 1:4 in suburban districts, and 1:10 in remote areas. Stays averaged 19.2 months. 1.81 million had jobs. About 74% came from Hebei, Henan, Zhejiang, Sichuan, Shandong, Jiangsu, and Anhui. Zhejiang migrants stayed the longest (24.9 months), while Jiangsu in-migrants stayed the shortest (16.6 months). PMID:12321925

1998-12-01

416

Monitoring natural and artificial radioactivity enhancement in the Aegean Sea using floating measuring systems.  

PubMed

In the present work, the enhancement of radioactivity due to rainfall in the Aegean Sea using floating measuring systems was observed and quantified. The data were acquired with a NaI underwater detection system, which was installed on a floating measuring system at a depth of 3m. The results of natural and artificial radioactivity are discussed taking into account the rainfall intensity and wind direction. The activity concentration of (214)Bi increased up to (991+/-102)Bq/m(3) after strong rainfall in the North Aegean Sea in winter (humid period) with east wind direction. On other hand, the maximum activity concentration reached the level of (110+/-10)Bq/m(3) in summer (dry period) during south winds. PMID:18495486

Tsabaris, C

2008-04-12

417

Band gap narrowing of titanium dioxide (TiO2) nanocrystals by electrochemically active biofilms and their visible light activity  

NASA Astrophysics Data System (ADS)

We report a simple biogenic-route to narrow the band gap of TiO2 nanocrystals for visible light application by offering a greener method. When an electrochemically active biofilm (EAB) was challenged with a solution of Degussa-TiO2 using sodium acetate as the electron donor, greyish blue-colored TiO2 nanocrystals were obtained. A band gap study showed that the band gap of the modified TiO2 nanocrystals was significantly reduced (Eg = 2.85 eV) compared to the unmodified white Degussa TiO2 (Eg = 3.10 eV).

Kalathil, Shafeer; Khan, Mohammad Mansoob; Ansari, Sajid Ali; Lee, Jintae; Cho, Moo Hwan

2013-06-01

418

Light Activates Output from Evening Neurons and Inhibits Output from Morning Neurons in the Drosophila Circadian Clock  

PubMed Central

Animal circadian clocks are based on multiple oscillators whose interactions allow the daily control of complex behaviors. The Drosophila brain contains a circadian clock that controls rest–activity rhythms and relies upon different groups of PERIOD (PER)–expressing neurons. Two distinct oscillators have been functionally characterized under light-dark cycles. Lateral neurons (LNs) that express the pigment-dispersing factor (PDF) drive morning activity, whereas PDF-negative LNs are required for the evening activity. In constant darkness, several lines of evidence indicate that the LN morning oscillator (LN-MO) drives the activity rhythms, whereas the LN evening oscillator (LN-EO) does not. Since mutants devoid of functional CRYPTOCHROME (CRY), as opposed to wild-type flies, are rhythmic in constant light, we analyzed transgenic flies expressing PER or CRY in the LN-MO or LN-EO. We show that, under constant light conditions and reduced CRY function, the LN evening oscillator drives robust activity rhythms, whereas the LN morning oscillator does not. Remarkably, light acts by inhibiting the LN-MO behavioral output and activating the LN-EO behavioral output. Finally, we show that PDF signaling is not required for robust activity rhythms in constant light as opposed to its requirement in constant darkness, further supporting the minor contribution of the morning cells to the behavior in the presence of light. We therefore propose that day–night cycles alternatively activate behavioral outputs of the Drosophila evening and morning lateral neurons.

Picot, Marie; Cusumano, Paola; Klarsfeld, Andre; Ueda, Ryu; Rouyer, Francois

2007-01-01

419

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

PubMed

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

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

2013-09-24

420

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

PubMed Central

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

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

2013-01-01

421

Porous carrier based floating granular delivery system of repaglinide.  

PubMed

A floating granular delivery system consisting of calcium silicate (CS) as porous carrier; repaglinide (Rg), an oral hypoglycemic agent; and hydroxypropyl methylcellulose K4M (HPMC K4M), ethyl cellulose (EC) and carbopol 940 (CP940) as matrix forming polymers was prepared and evaluated for its gastro-retentive and controlled release properties. The effect of various formulation and process variables on the particle morphology, micromeritic properties, in vitro floating behavior, drug content (%) and in vitro drug release was studied. The transit of floating granules of optimized formulation in the gastrointestinal (GI) tract was monitored by gamma scintigraphy in albino rabbits. The optimized formulation was compared in vivo with lactose granules (RgSCLG) prepared from identical polymers with their optimized composition ratio. Repaglinide-loaded optimized formulation was orally administered to albino rabbits and blood samples collected were used to determine pharmacokinetic parameters of Rg from floating granular formulation. Results were compared with pharmacokinetic parameters of marketed tablet formulation of Rg. The optimized formulation (RgSCG4) demonstrated favorable in vitro floating and release characteristics. Prolonged gastric residence time (GRT) of over 6 hr was achieved in all subjects for calcium silicate based floating granules of Rg. The relative bioavailability of Rg-loaded floating granules increased 3.8-fold in comparison to that of its marketed capsule. The designed system, combining excellent buoyant ability and suitable drug release pattern, offered clear advantages in terms of increased bioavailability of repaglinide. PMID:17523003

Jain, Sunil K; Agrawal, Govind P; Jain, Narendra K

2007-04-01

422

Effects of light intensity on animal husbandry and digestive enzyme activities in sea bass Dicentrachus labrax post-larvae  

Microsoft Academic Search

A 3-week experiment was carried out to investigate the effects of light intensity on animal husbandry performances (mainly growth, survival and cannibalism rates) and their relationships with digestive enzyme activities (pepsin, trypsin, chymotrypsin and amylase) in sea bass post-larvae. Four light intensities (5, 50, 100 and 400 lx) were compared in triplicate. Fish (initial body weight: 34 mg) were automatically

Armande Cuvier-Péres; Stéphane Jourdan; Pascal Fontaine; Patrick Kestemont

2001-01-01

423

Simulation of tin penetration process in the surface layer of soda-lime-silica float glass  

Microsoft Academic Search

Based on the analysis of tin penetration mechanism in the float glass process, the oxidation model of stannous ion is constructed\\u000a considering the oxygen activity and the redox reaction in the glass surface layer. The calculation of stannous ion’s oxidation\\u000a rate makes it possible to predict both stannous and stannic ion’s concentrations independently. And it is also the necessary\\u000a precondition

Qin Zhang; ZeJing Chen; ZhiXin Li

2011-01-01

424

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

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

425

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

NASA Astrophysics Data System (ADS)

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

Shi, Yanfen; Chen, Feng; Zhang, Jinlong

2013-01-01

426

Optics Arrangements Including Light Source Arrangements for an Active Matrix Liquid Crystal Image Generator.  

National Technical Information Service (NTIS)

A system for producing modulated light is disclosed. The system comprises a spatial light modulator including a light modulating medium switchable between different states so as to act on light in ways which form overall patterns of modulated light. The s...

H. Chase M. A. Handschy M. R. Meadows

2005-01-01

427

Design of efficient thermally activated delayed fluorescence materials for pure blue organic light emitting diodes.  

PubMed

Efficient thermally activated delayed fluorescence (TADF) has been characterized for a carbazole/sulfone derivative in both solutions and doped films. A pure blue organic light emitting diode (OLED) based on this compound demonstrates a very high external quantum efficiency (EQE) of nearly 10% at low current density. Because TADF only occurs in a bipolar system where donor and acceptor centered (3)??* states are close to or higher than the triplet intramolecular charge transfer ((3)CT) state, control of the ?-conjugation length of both donor and acceptor is considered to be as important as breaking the ?-conjugation between them in blue TADF material design. PMID:22931361

Zhang, Qisheng; Li, Jie; Shizu, Katsuyuki; Huang, Shuping; Hirata, Shuzo; Miyazaki, Hiroshi; Adachi, Chihaya

2012-08-29

428

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?m 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

429

Tunable Conductivity and Conduction Mechanism in a UV light activated electronic conductor  

Microsoft Academic Search

A tunable conductivity has been achieved by controllable substitution of a\\u000anovel UV light activated electronic conductor. The transparent conducting oxide\\u000asystem H-doped Ca12-xMgxAl14O33 (x = 0; 0.1; 0.3; 0.5; 0.8; 1.0) presents a\\u000aconductivity that is strongly dependent on the substitution level and\\u000atemperature. Four-point dc-conductivity decreases with x from 0.26 S\\/cm (x = 0)\\u000ato 0.106 S\\/cm (x

Mariana I. Bertoni; Thomas O. Masona; Julia E. Medvedeva; Arthur J. Freeman; Kenneth R. Poeppelmeier; Bernard Delley

2004-01-01

430

Tunable conductivity and conduction mechanism in an ultraviolet light activated electronic conductor  

Microsoft Academic Search

A tunable conductivity has been achieved by controllable substitution of an ultraviolet light activated electronic conductor. The transparent conducting oxide system H-doped Ca12-xMgxAl14O33 (x=0,0.1,0.3,0.5,0.8,1.0) presents a conductivity that is strongly dependent on the substitution level and temperature. Four-point dc-conductivity decreases with x from 0.26 S\\/cm (x=0) to 0.106 S\\/cm (x=1) at room temperature. At each composition the conductivity increases (reversibly

Mariana I. Bertoni; Thomas O. Mason; Julia E. Medvedeva; Arthur J. Freeman; Kenneth R. Poeppelmeier; Bernard Delley

2005-01-01

431

Tunable conductivity and conduction mechanism in an ultraviolet light activated electronic conductor  

Microsoft Academic Search

A tunable conductivity has been achieved by controllable substitution of an ultraviolet light activated electronic conductor. The transparent conducting oxide system H-doped Ca12?xMgxAl14O33(x=0,0.1,0.3,0.5,0.8,1.0) presents a conductivity that is strongly dependent on the substitution level and temperature. Four-point dc-conductivity decreases with x from 0.26 S?cm(x=0) to 0.106 S?cm(x=1) at room temperature. At each composition the conductivity increases (reversibly with temperature) until

Mariana I. Bertoni; Thomas O. Mason; Julia E. Medvedeva; Arthur J. Freeman; Kenneth R. Poeppelmeier; Bernard Delley

2005-01-01

432

Recent advances in gastric floating drug delivery technology: a review.  

PubMed

Gastric floating drug delivery systems have been an avenue of considerable interest in terms of their immense potential for better pharmacotherapeutic interventions along with site-specific absorption. These buoyant systems significantly enhance the bioavailability and controlled delivery of several drug molecules. Scientific investigators have also carried out substantial research endeavours worldwide in order to design a more systematic and intellectual floating systems. The present manuscript is an attempt to highlight numerous recent advancements in the design of gastric floating drug delivery systems along with various available commercial preparations. Salient applications, characterization aspects and future perspectives of these multifarious systems have also been addressed. PMID:23808593

Pahwa, Rakesh; Bisht, Seema; Kumar, Vipin; Kohli, Kanchan

2013-06-01

433

Differential metabolomics unraveling light/dark regulation of metabolic activities in Arabidopsis cell culture.  

PubMed

Differential metabolomics based on a non-targeted FT-ICR/MS analysis demonstrated metabolite accumulation patterns reflecting light/dark conditions in Arabidopsis T87 cell culture. First, FT-ICR/MS data sets were converted into metabolome information using the Dr.DMASS software (http://kanaya.naist.jp/DrDMASS/). A quick search of a metabolite-species database, KNApSAcK (http://kanaya.naist.jp/KNApSAcK/), was implemented to assign metabolite candidates to each accurate MS data (<1 ppm) through the prediction of molecular formulas, and the candidate structures were further studied using MS/MS analyses. Specific metabolites representing the culture conditions included sugars, phenylpropanoid derivatives, flavonol aglycons, and a plastid nonmevalonate pathway intermediate. Transcriptomics data were obtained in parallel and analyzed using a transcriptome analysis tool, KaPPA-View (http://kpv.kazusa.or.jp/kappa-view/). The specific accumulation patterns of flavonol aglycons were in good agreement with the light/dark regulation of a cytochrome P450 gene, CYP75B, and the build-up of 2-C-methyl-D-erythritol 4-phosphate, a nonmevalonate pathway intermediate, in the light grown cells was also consistent with a gene expression profile. The differential metablomics scheme based on the FT-ICR/MS metabolomics can serve as an evaluation system of metabolic activities contributing to successful identification and proper manipulation of key enzymatic steps in metabolic engineering studies. PMID:17701204

Nakamura, Yukiko; Kimura, Atsuko; Saga, Hirohisa; Oikawa, Akira; Shinbo, Yoko; Kai, Kosuke; Sakurai, Nozomu; Suzuki, Hideyuki; Kitayama, Masahiko; Shibata, Daisuke; Kanaya, Shigehiko; Ohta, Daisaku

2007-08-15

434

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

435

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

436

Performance Study of the Two-Stage Light Gas Gun for Active TIP Probes  

NASA Astrophysics Data System (ADS)

The Transient Internal Probe (TIP) is a diagnostic for measuring local parameters across a cord of a plasma using a refractory-clad probe that traverses the plasma at a speed of 1.8 km/sec, fast enough that heating of the probe will not cause significant ablation during transit. To date, TIP has used passive magneto-optic probes illuminated during transit by a polarized laser, and having a retroreflector to return light to an ellipsometer after a double-pass through the probe. One component of the local magnetic fields is deduced by Faraday rotation of the return light. Electro-optic probes have also been studied. A richer set of parameters, potentially including plasma temperature and density, would be afforded by active TIP probes, using on-board microelectronic sensors; information would be encoded by modulation of radiation generated on-board (i.e., LED or laser diode). This approach also avoids distortion of signals from passive probes created by stress-induced polarization effects. At issue is the survivability of on-board microelectronics under acceleration of the probe by a two-stage light-gas gun. This paper describes analytical and experimental studies of acceleration of TIP probes versus gun operating parameters. The results will be used to determine optimal gun parameters for minimizing acceleration stress, while still reaching the needed probe speeds of 1.6-1.8 km/sec.

Kim, H.; Jarboe, T. R.; Mattick, A. T.; Smith, R. J.

2002-11-01

437

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

438

Enzymes of Choline Synthesis in Spinach (Response of Phospho-Base N-Methyltransferase Activities to Light and Salinity).  

PubMed Central

In spinach (Spinacia oleracea L.), choline is synthesized by the sequential N-methylation of phosphoethanolamine -> phosphomono- -> phosphodi- -> phosphotrimethylethanolamine (i.e. phosphocholine) followed by hydrolysis to release choline. Differential centrifugation of spinach leaf extracts shows that enzymes catalyzing the three N-methylations are cytosolic. These enzymes were assayed in leaf extracts prepared from plants growing under various light/dark periods. Under a diurnal, 8-h light/16-h dark photoperiod, the activity of the enzyme catalyzing the N-methylation of phosphoethanolamine is highest at the end of the light period and lowest following the dark period. Prolonged dark periods (exceeding 16 h) lead to a further reduction in the activity of this enzyme, although activity is restored when plants are reexposed to light. In contrast, the activity of the enzyme(s) catalyzing the N-methylations of phosphomono- and phosphodimethylethanolamine does not undergo comparable changes in response to light/dark treatments. Salt shock of plants with 200 mM NaCl results in a 2-fold increase in all three N-methylation activities relative to nonsalinized controls but only in plants exposed to light. Thus, light is required for the salt-responsive up-regulation of choline synthesis in spinach.

Weretilnyk, E. A.; Smith, D. D.; Wilch, G. A.; Summers, P. S.

1995-01-01

439

Efficient visible light-active N-doped TiO2 photocatalysts by a reproducible and controllable synthetic route.  

PubMed

A reproducible and controllable method allows the synthesis of practical quantities of efficient, visible light active TiO(2)(N) photocatalysts in which the nitrogen content may be varied to achieve optimum performance. PMID:17031443

In, Suil; Orlov, Alexander; García, Felipe; Tikhov, Mintcho; Wright, Dominic S; Lambert, Richard M

2006-08-31

440

A highly luminescent spiro-anthracenone-based organic light-emitting diode exhibiting thermally activated delayed fluorescence.  

PubMed

Efficient thermally activated delayed fluorescence was observed from a spiro-anthracenone derivative (ACRSA). An organic light-emitting diode containing ACRSA exhibited blue-greenish electroluminescence with a maximum external quantum efficiency of 16.5%. PMID:24071893

Nasu, Keiro; Nakagawa, Tetsuya; Nomura, Hiroko; Lin, Chi-Jen; Cheng, Chien-Hong; Tseng, Mei-Rurng; Yasuda, Takuma; Adachi, Chihaya

2013-10-10

441

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

442

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

443

Laser-diode-heated floating zone (LDFZ) method appropriate to crystal growth of incongruently melting materials  

NASA Astrophysics Data System (ADS)

We have developed a laser-diode-heated floating zone (LDFZ) method, in order to improve the broad and inhomogeneous light focusing in the conventional lamp-heated floating zone method, which often causes difficulties in the crystal growth especially for the incongruently melting materials. We have simulated the light focusing properties of the LDFZ method to make the whole of the molten zone irradiated with concentrated and homogeneous laser lights. We have designed and assembled an LDFZ furnace, and have demonstrated how it works through actual crystal growth. The method is applicable to various kinds of materials, and enables stable and reproducible crystal growth even for the incongruently melting materials. We have succeeded in the crystal growth of representatives of the incongruently melting materials such as BiFeO3 and (La,Ba)2CuO4, which were believed to be difficult to be grown by the conventional method. Tolerance to the decentering of samples and highly efficient heating are also established in the LDFZ method.

Ito, Toshimitsu; Ushiyama, Tomoharu; Yanagisawa, Yuji; Tomioka, Yasuhide; Shindo, Isamu; Yanase, Atsushi

2013-01-01

444

Chloroplast NADP-malate dehydrogenase: structural basis of light-dependent regulation of activity by thiol oxidation and reduction  

Microsoft Academic Search

Background: NADP-dependent malate dehydrogenase (EC 1.1.1.82) is a light-activated chloroplast enzyme that functions in the C4 pathway of photosynthesis. The light regulation is believed to be mediated in vivo by thioredoxin-catalyzed reduction and re-oxidation of cystine residues. The rates of reversible activation and inactivation of the enzyme are strongly influenced by the coenzyme substrates that seem to ultimately determine the

Paul D Carr; Denis Verger; Anthony R Ashton; David L Ollis

1999-01-01

445

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

Microsoft Academic Search

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

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

1997-01-01

446

Direct Modulation of Activity and Body Temperature of Owl Monkeys (Aotus lemurinus griseimembra) by Low Light Intensities  

Microsoft Academic Search

The activity pattern of Aotus lemurinus griseimembra can be predictably altered by varying the illuminance during the dark phase of a 12:12-hour light:dark rhythm. Intensities well below full-moon brightness (0.1–0.5 1x) severely inhibit activity. This modulation is not the result of a light-induced phase shift of the circadian rhythm, but it is primarily caused by masking due to direct effects

H. G. Erkert; J. Gröber

1986-01-01

447

Designs and applications for floating-hydro power systems in small streams  

Microsoft Academic Search

The project focuses on an appropriate technology for small-scale hydro power: floating waterwheels and turbines. For background, relic and existing systems such as early floating mills, traditional Amish waterwheels, and micro-hydro systems are examined. In the design phase of the project, new designs for Floating Hydro Power Systems include: an analysis of floatation materials and systems; a floating undershot waterwheel

Rehder

1983-01-01

448

Early-light embryonic stimulation suggests a second route, via gene activation, to cerebral lateralization in vertebrates  

PubMed Central

Genetic factors determine the asymmetrical position of vertebrate embryos allowing asymmetric environmental stimulation to shape cerebral lateralization. In birds, late-light stimulation, just before hatching, on the right optic nerve triggers anatomical and functional cerebral asymmetries. However, some brain asymmetries develop in absence of embryonic light stimulation. Furthermore, early-light action affects lateralization in the transparent zebrafish embryos before their visual system is functional. Here we investigated whether another pathway intervenes in establishing brain specialization. We exposed chicks' embryos to light before their visual system was formed. We observed that such early stimulation modulates cerebral lateralization in a comparable vein of late-light stimulation on active retinal cells. Our results show that, in a higher vertebrate brain, a second route, likely affecting the genetic expression of photosensitive regions, acts before the development of a functional visual system. More than one sensitive period seems thus available to light stimulation to trigger brain lateralization.

Chiandetti, Cinzia; Galliussi, Jessica; Andrew, Richard J.; Vallortigara, Giorgio

2013-01-01

449

Controlling an actively-quenched single photon detector with bright light.  

PubMed

We control using bright light an actively-quenched avalanche single-photon detector. Actively-quenched detectors are commonly used for quantum key distribution (QKD) in the visible and near-infrared range. This study shows that these detectors are controllable by the same attack used to hack passively-quenched and gated detectors. This demonstrates the generality of our attack and its possible applicability to eavsdropping the full secret key of all QKD systems using avalanche photodiodes (APDs). Moreover, the commercial detector model we tested (PerkinElmer SPCM-AQR) exhibits two new blinding mechanisms in addition to the previously observed thermal blinding of the APD, namely: malfunctioning of the bias voltage control circuit, and overload of the DC/DC converter biasing the APD. These two new technical loopholes found just in one detector model suggest that this problem must be solved in general, by incorporating generally imperfect detectors into the security proof for QKD. PMID:22109239

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

2011-11-01

450

Synthesis and characterization of substitutional and interstitial nitrogen-doped titanium dioxides with visible light photocatalytic activity  

NASA Astrophysics Data System (ADS)

Both substitutional and interstitial nitrogen-doped titanium dioxides (N-TiO2) were prepared. Their surface states were clarified by XPS spectra of N 1s, O 1s and Ti 2p. The results of photocatalysis show that both substitutional and interstitial N impurities greatly enhance the photoactivity of TiO2 in visible light. Moreover, the visible light activity of interstitial N-doped TiO2 is higher than that of substitutional N-doped TiO2. The microwave synthesis presented in this paper is a promising and practical method to produce interstitial nitrogen-doped photocatalysts with high visible light activity.

Peng, Feng; Cai, Lingfeng; Yu, Hao; Wang, Hongjuan; Yang, Jian

2008-01-01

451

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

452

Surface-active and Light-absorbing Secondary Organic Aerosol (SOA) Material  

NASA Astrophysics Data System (ADS)

We have observed the formation of light-absorbing, high-molecular-weight, and surface-active organics from methylgyloxal interacting with ammonium salts in aqueous aerosol mimics. Mixtures of methylglyoxal and glyoxal also form light-absorbing products and exhibit surface tension depression with a Langmuir-like dependence on initial methylglyoxal concentration. We used chemical ionization mass spectrometry with a volatilization flow tube inlet (Aerosol-CIMS) to characterize the product species. The results are consistent with aldol condensation products, carbon-nitrogen species, sulfur-containing compounds, and oligomeric species up to 759 amu. These observations have potentially significant implications for our understanding of the effects of SOA on climate, since a) SOA are typically treated as non-absorbing in climate models, and b) surface tension depression in aqueous aerosols by SOA material may result in increased cloud condensation nucleus (CCN) activity. Furthermore, surface film formation could affect aerosol heterogeneous chemistry. We will also discuss aerosol flow tube O3 oxidation experiments designed to determine the atmospheric lifetimes of the observed product compounds.

McNeill, V. F.; Sareen, N.; Schwier, A. N.; Shapiro, E. L.

2009-12-01

453

5. GENERAL VIEW LOOKING NORTHWEST. FENDER PREVENTS FLOATING DEBRIS FROM ...  

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

5. GENERAL VIEW LOOKING NORTHWEST. FENDER PREVENTS FLOATING DEBRIS FROM DAMAGING TRUSSES DURING PERIODS OF HIGH WATER. - Ohio & Erie Canal, Tinker's Creek Aqueduct, Canal Road, South Tinkers Creek Road, Valley View, Cuyahoga County, OH

454

36. FLOAT WELL AND PIPE ENCASEMENT EAST CUTOFF WALL, ...  

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

36. FLOAT WELL AND PIPE ENCASEMENT - EAST CUTOFF WALL, REINFORCEMENT DETAILS. Sheet A-17, October, 1940. File no. SA 342/2. - Prado Dam, Outlet Works, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

455

Analog-to-Digital Converter 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...

2006-01-01

456

Digital-to-Analog Converter 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 M. R. Kucic P. E. Hasler

2006-01-01

457

14 CFR 29.521 - Float landing conditions.  

Code of Federal Regulations, 2013 CFR

...TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Strength Requirements Water Loads § 29.521 Float landing conditions...the static level attitude, the resultant water reaction passes vertically through the...

2013-01-01

458

Coupled Dynamic Modeling of Floating Wind Turbine Systems.  

National Technical Information Service (NTIS)

This article presents a collaborative research program that the Massachusetts Institute of Technology (MIT) and the National Renewable Energy Laboratory (NREL) have undertaken to develop innovative and cost-effective floating and mooring systems for offsh...

E. N. Wayman P. D. Sclavounos

2006-01-01

459

40. VAL CONNECTING BRIDGE AND BARGES FLOATING ON RESERVOIR (PREVIOUSLY ...  

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

40. VAL CONNECTING BRIDGE AND BARGES FLOATING ON RESERVOIR (PREVIOUSLY SUPPORTED MUZZLE END OF LAUNCHER BRIDGE). - Variable Angle Launcher Complex, Variable Angle Launcher, CA State Highway 39 at Morris Reservior, Azusa, Los Angeles County, CA

460

16. EAST ELEVATION OF FLOAT HOUSE AND FISH WATER RELEASE ...  

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

16. EAST ELEVATION OF FLOAT HOUSE AND FISH WATER RELEASE OUTLET. PART OF ENERGY DISSIPATING BAFFLE PIER SYSTEM IS VISIBLE AT LEFT. - Pit 4 Diversion Dam, Pit River west of State Highway 89, Big Bend, Shasta County, CA