WorldWideScience

Sample records for click source levels

  1. Hearing sensation levels of emitted biosonar clicks in an echolocating Atlantic bottlenose dolphin.

    Directory of Open Access Journals (Sweden)

    Songhai Li

    Full Text Available Emitted biosonar clicks and auditory evoked potential (AEP responses triggered by the clicks were synchronously recorded during echolocation in an Atlantic bottlenose dolphin (Tursiops truncatus trained to wear suction-cup EEG electrodes and to detect targets by echolocation. Three targets with target strengths of -34, -28, and -22 dB were used at distances of 2 to 6.5 m for each target. The AEP responses were sorted according to the corresponding emitted click source levels in 5-dB bins and averaged within each bin to extract biosonar click-related AEPs from noise. The AEP amplitudes were measured peak-to-peak and plotted as a function of click source levels for each target type, distance, and target-present or target-absent condition. Hearing sensation levels of the biosonar clicks were evaluated by comparing the functions of the biosonar click-related AEP amplitude-versus-click source level to a function of external (in free field click-related AEP amplitude-versus-click sound pressure level. The results indicated that the dolphin's hearing sensation levels to her own biosonar clicks were equal to that of external clicks with sound pressure levels 16 to 36 dB lower than the biosonar click source levels, varying with target type, distance, and condition. These data may be assumed to indicate that the bottlenose dolphin possesses effective protection mechanisms to isolate the self-produced intense biosonar beam from the animal's ears during echolocation.

  2. Using line acceleration to measure false killer whale (Pseudorca crassidens) click and whistle source levels during pelagic longline depredation.

    Science.gov (United States)

    Thode, Aaron; Wild, Lauren; Straley, Janice; Barnes, Dustin; Bayless, Ali; O'Connell, Victoria; Oleson, Erin; Sarkar, Jit; Falvey, Dan; Behnken, Linda; Martin, Sean

    2016-11-01

    False killer whales (Pseudorca crassidens) depredate pelagic longlines in offshore Hawaiian waters. On January 28, 2015 a depredation event was recorded 14 m from an integrated GoPro camera, hydrophone, and accelerometer, revealing that false killer whales depredate bait and generate clicks and whistles under good visibility conditions. The act of plucking bait off a hook generated a distinctive 15 Hz line vibration. Two similar line vibrations detected at earlier times permitted the animal's range and thus signal source levels to be estimated over a 25-min window. Peak power spectral density source levels for whistles (4-8 kHz) were estimated to be between 115 and 130 dB re 1 μPa 2 /Hz @ 1 m. Echolocation click source levels over 17-32 kHz bandwidth reached 205 dB re 1 μPa @ 1 m pk-pk, or 190 dB re 1 μPa @ 1 m (root-mean-square). Predicted detection ranges of the most intense whistles are 10 to 25 km at respective sea states of 4 and 1, with click detection ranges being 5 times smaller than whistles. These detection range analyses provide insight into how passive acoustic monitoring might be used to both quantify and avoid depredation encounters.

  3. Click-Evoked Auditory Efferent Activity: Rate and Level Effects.

    Science.gov (United States)

    Boothalingam, Sriram; Kurke, Julianne; Dhar, Sumitrajit

    2018-05-07

    There currently are no standardized protocols to evaluate auditory efferent function in humans. Typical tests use broadband noise to activate the efferents, but only test the contralateral efferent pathway, risk activating the middle ear muscle reflex (MEMR), and are laborious for clinical use. In an attempt to develop a clinical test of bilateral auditory efferent function, we have designed a method that uses clicks to evoke efferent activity, obtain click-evoked otoacoustic emissions (CEOAEs), and monitor MEMR. This allows for near-simultaneous estimation of cochlear and efferent function. In the present study, we manipulated click level (60, 70, and 80 dB peak-equivalent sound pressure level [peSPL]) and rate (40, 50, and 62.5 Hz) to identify an optimal rate-level combination that evokes measurable efferent modulation of CEOAEs. Our findings (n = 58) demonstrate that almost all click levels and rates used caused significant inhibition of CEOAEs, with a significant interaction between level and rate effects. Predictably, bilateral activation produced greater inhibition compared to stimulating the efferents only in the ipsilateral or contralateral ear. In examining the click rate-level effects during bilateral activation in greater detail, we observed a 1-dB inhibition of CEOAE level for each 10-dB increase in click level, with rate held constant at 62.5 Hz. Similarly, a 10-Hz increase in rate produced a 0.74-dB reduction in CEOAE level, with click level held constant at 80 dB peSPL. The effect size (Cohen's d) was small for either monaural condition and medium for bilateral, faster-rate, and higher-level conditions. We were also able to reliably extract CEOAEs from efferent eliciting clicks. We conclude that clicks can indeed be profitably employed to simultaneously evaluate cochlear health using CEOAEs as well as their efferent modulation. Furthermore, using bilateral clicks allows the evaluation of both the crossed and uncrossed elements of the auditory

  4. Recording and quantification of ultrasonic echolocation clicks from free-ranging toothed whales

    DEFF Research Database (Denmark)

    Madsen, Peter Teglberg; Wahlberg, Magnus

    2007-01-01

    Toothed whales produce short, ultrasonic clicks of high directionality and source level to probe their environment acoustically. This process, termed echolocation, is to a large part governed by the properties of the emitted clicks. Therefore derivation of click source parameters from free......-ranging animals is of increasing importance to understand both how toothed whales use echolocation in the wild and how they may be monitored acoustically. This paper addresses how source parameters can be derived from free-ranging toothed whales in the wild using calibrated multi-hydrophone arrays and digital...... of discrete versions of toothed whale clicks that are meaningful in a biosonar context....

  5. Comparison of echolocation clicks from geographically sympatric killer whales and long-finned pilot whales

    DEFF Research Database (Denmark)

    Eskesen, Ida; Wahlberg, Magnus; Simon, Malene

    2010-01-01

    The source characteristics of biosonar signals from sympatric killer whales and long-finned pilot whales in a Norwegian fjord were compared. A total of 137 pilot whale and more than 2000 killer whale echolocation clicks were recorded using a linear four-hydrophone array. Of these, 20 pilot whale...... clicks and 28 killer whale clicks were categorized as being recorded on-axis. The clicks of pilot whales had a mean apparent source level of 196 dB re 1 lPa pp and those of killer whales 203 dB re 1 lPa pp. The duration of pilot whale clicks was significantly shorter (23 ls, S.E.¼1.3) and the centroid...... frequency significantly higher (55 kHz, S.E.¼2.1) than killer whale clicks (duration: 41 ls, S.E.¼2.6; centroid frequency: 32 kHz, S.E.¼1.5). The rate of increase in the accumulated energy as a function of time also differed between clicks from the two species. The differences in duration, frequency...

  6. Effect of Broadband Nature of Marine Mammal Echolocation Clicks on Click-Based Population Density Estimates

    Science.gov (United States)

    2014-09-30

    No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing...will be applied also to other species such as sperm whale (Physeter macrocephalus) (whose high source level assures long range detection and amplifies...improve the accuracy of marine mammal density estimation based on counting echolocation clicks, and will be applicable to density estimates obtained

  7. AutoClickChem: click chemistry in silico.

    Directory of Open Access Journals (Sweden)

    Jacob D Durrant

    Full Text Available Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

  8. AutoClickChem: click chemistry in silico.

    Science.gov (United States)

    Durrant, Jacob D; McCammon, J Andrew

    2012-01-01

    Academic researchers and many in industry often lack the financial resources available to scientists working in "big pharma." High costs include those associated with high-throughput screening and chemical synthesis. In order to address these challenges, many researchers have in part turned to alternate methodologies. Virtual screening, for example, often substitutes for high-throughput screening, and click chemistry ensures that chemical synthesis is fast, cheap, and comparatively easy. Though both in silico screening and click chemistry seek to make drug discovery more feasible, it is not yet routine to couple these two methodologies. We here present a novel computer algorithm, called AutoClickChem, capable of performing many click-chemistry reactions in silico. AutoClickChem can be used to produce large combinatorial libraries of compound models for use in virtual screens. As the compounds of these libraries are constructed according to the reactions of click chemistry, they can be easily synthesized for subsequent testing in biochemical assays. Additionally, in silico modeling of click-chemistry products may prove useful in rational drug design and drug optimization. AutoClickChem is based on the pymolecule toolbox, a framework that may facilitate the development of future python-based programs that require the manipulation of molecular models. Both the pymolecule toolbox and AutoClickChem are released under the GNU General Public License version 3 and are available for download from http://autoclickchem.ucsd.edu.

  9. Clicking in shallow rivers: short-range echolocation of Irrawaddy and Ganges River dolphins in a shallow, acoustically complex habitat.

    Directory of Open Access Journals (Sweden)

    Frants H Jensen

    Full Text Available Toothed whales (Cetacea, odontoceti use biosonar to navigate their environment and to find and catch prey. All studied toothed whale species have evolved highly directional, high-amplitude ultrasonic clicks suited for long-range echolocation of prey in open water. Little is known about the biosonar signals of toothed whale species inhabiting freshwater habitats such as endangered river dolphins. To address the evolutionary pressures shaping the echolocation signal parameters of non-marine toothed whales, we investigated the biosonar source parameters of Ganges river dolphins (Platanista gangetica gangetica and Irrawaddy dolphins (Orcaella brevirostris within the river systems of the Sundarban mangrove forest. Both Ganges and Irrawaddy dolphins produced echolocation clicks with a high repetition rate and low source level compared to marine species. Irrawaddy dolphins, inhabiting coastal and riverine habitats, produced a mean source level of 195 dB (max 203 dB re 1 µPapp whereas Ganges river dolphins, living exclusively upriver, produced a mean source level of 184 dB (max 191 re 1 µPapp. These source levels are 1-2 orders of magnitude lower than those of similar sized marine delphinids and may reflect an adaptation to a shallow, acoustically complex freshwater habitat with high reverberation and acoustic clutter. The centroid frequency of Ganges river dolphin clicks are an octave lower than predicted from scaling, but with an estimated beamwidth comparable to that of porpoises. The unique bony maxillary crests found in the Platanista forehead may help achieve a higher directionality than expected using clicks nearly an octave lower than similar sized odontocetes.

  10. The ZeroAccess Auto-Clicking and Search-Hijacking Click Fraud Modules

    Science.gov (United States)

    2013-12-16

    payloads and instead began distributing Bitcoin miners and click fraud modules.3 From a technical perspective, the primary click fraud malware used in...this era operated in the indiscriminate “auto-clicking” fashion we describe in Section 5. Alongside the click fraud and Bitcoin payloads, ZeroAccess

  11. A comparison of muscular activity during single and double mouse clicks.

    Science.gov (United States)

    Thorn, Stefan; Forsman, Mikael; Hallbeck, Susan

    2005-05-01

    Work-related musculoskeletal disorders (WMSDs) in the neck/shoulder region and the upper extremities are a common problem among computer workers. Occurrences of motor unit (MU) double discharges with very short inter-firing intervals (doublets) have been hypothesised as a potential additional risk for overuse of already exhausted fibres during long-term stereotyped activity. Doublets are reported to be present during double-click mouse work tasks. A few comparative studies have been carried out on overall muscle activities for short-term tasks with single types of actions, but none on occurrences of doublets during double versus single clicks. The main purpose of this study was to compare muscle activity levels of single and double mouse clicks during a long-term combined mouse/keyboard work task. Four muscles were studied: left and right upper trapezius, right extensor digitorum communis (EDC) and right flexor carpi ulnaris. Additionally, MU activity was analysed through intramuscular electromyography in the EDC muscle for a selection of subjects. The results indicate that double clicking produces neither higher median or 90th percentile levels in the trapezius and EDC muscles, nor a higher disposition for MU doublets, than does single clicking. Especially for the 90th percentile levels, the indications are rather the opposite (in the EDC significantly higher during single clicks in 8 of 11 subjects, P < 0.05). Although it cannot be concluded from the present study that double clicks are harmless, there were no signs that double clicks during computer work generally constitute a larger risk factor for WMSDs than do single clicks.

  12. Echolocation click source parameters of Australian snubfin dolphins (Orcaella heinsohni)

    DEFF Research Database (Denmark)

    de Freitas, Mafalda; Smith, Joshua N; Jensen, Frants H

    2018-01-01

    The Australian snubfin dolphin (Orcaella heinsohni) is endemic to Australian waters, yet little is known about its abundance and habitat use. To investigate the feasibility of Passive Acoustic Monitoring for snubfin dolphins, biosonar clicks were recorded in Cygnet Bay, Australia, using a four-el...

  13. Clicking in a killer whale habitat: narrow-band, high-frequency biosonar clicks of harbour porpoise (Phocoena phocoena and Dall's porpoise (Phocoenoides dalli.

    Directory of Open Access Journals (Sweden)

    Line A Kyhn

    Full Text Available Odontocetes produce a range of different echolocation clicks but four groups in different families have converged on producing the same stereotyped narrow band high frequency (NBHF click. In microchiropteran bats, sympatric species have evolved the use of different acoustic niches and subtly different echolocation signals to avoid competition among species. In this study, we examined whether similar adaptations are at play among sympatric porpoise species that use NBHF echolocation clicks. We used a six-element hydrophone array to record harbour and Dall's porpoises in British Columbia (BC, Canada, and harbour porpoises in Denmark. The click source properties of all porpoise groups were remarkably similar and had an average directivity index of 25 dB. Yet there was a small, but consistent and significant 4 kHz difference in centroid frequency between sympatric Dall's (137±3 kHz and Canadian harbour porpoises (141±2 kHz. Danish harbour porpoise clicks (136±3 kHz were more similar to Dall's porpoise than to their conspecifics in Canada. We suggest that the spectral differences in echolocation clicks between the sympatric porpoises are consistent with evolution of a prezygotic isolating barrier (i.e., character displacement to avoid hybridization of sympatric species. In practical terms, these spectral differences have immediate application to passive acoustic monitoring.

  14. Feeding at a high pitch: Source parameters of narrow band,high-frequency clicks from echolocating off-shore hourglassdolphins and coastal Hector's dolphins

    DEFF Research Database (Denmark)

    Kyhn, Line Anker; Tougaard, Jakob; Jensen, Frants Havmand

    2009-01-01

    Toothed whales depend on echolocation for orientation and prey localization, and source parameters of echolocation clicks from free-ranging animals therefore convey valuable information about the acoustic physiology and behavioral ecology of the recorded species. Recordings of wild hourglass (Lag...

  15. Sperm whale clicks

    DEFF Research Database (Denmark)

    Møhl, Bertel; Wahlberg, Magnus; Madsen, Peter T.

    2000-01-01

    . A sound generator weighing upward of 10 tons and with a cross-section of 1 m is expected to generate high-intensity, directional sounds. This prediction from the Norris and Harvey theory is not supported by published data for sperm whale clicks ~source levels of 180 dB re 1 mPa and little, if any......In sperm whales ~Physeter catodon L. 1758! the nose is vastly hypertrophied, accounting for about one-third of the length or weight of an adult male. Norris and Harvey @in Animal Orientation and Navigation, NASA SP-262 ~1972!, pp. 397–417# ascribed a sound-generating function to this organ complex......, directionality!. Either the theory is not borne out or the data is not representative for the capabilities of the sound-generating mechanism. To increase the amount of relevant data, a five-hydrophone array, suspended from three platforms separated by 1 km and linked by radio, was deployed at the slope...

  16. Click chemistry for the conservation of cellular structures and fluorescent proteins: ClickOx.

    Science.gov (United States)

    Löschberger, Anna; Niehörster, Thomas; Sauer, Markus

    2014-05-01

    Reactive oxygen species (ROS), including hydrogen peroxide, are known to cause structural damage not only in living, but also in fixed, cells. Copper-catalyzed azide-alkyne cycloaddition (click chemistry) is known to produce ROS. Therefore, fluorescence imaging of cellular structures, such as the actin cytoskeleton, remains challenging when combined with click chemistry protocols. In addition, the production of ROS substantially weakens the fluorescence signal of fluorescent proteins. This led us to develop ClickOx, which is a new click chemistry protocol for improved conservation of the actin structure and better conservation of the fluorescence signal of green fluorescent protein (GFP)-fusion proteins. Herein we demonstrate that efficient oxygen removal by addition of an enzymatic oxygen scavenger system (ClickOx) considerably reduces ROS-associated damage during labeling of nascent DNA with ATTO 488 azide by Cu(I)-catalyzed click chemistry. Standard confocal and super-resolution fluorescence images of phalloidin-labeled actin filaments and GFP/yellow fluorescent protein-labeled cells verify the conservation of the cytoskeleton microstructure and fluorescence intensity, respectively. Thus, ClickOx can be used advantageously for structure preservation in conventional and most notably in super-resolution microscopy methods. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. "Click" i polymerer 2

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    2012-01-01

    "Click"-reaktioner til fremstilling af ledende polymerer med funktionelle håndtag og bipolymermaterialer......"Click"-reaktioner til fremstilling af ledende polymerer med funktionelle håndtag og bipolymermaterialer...

  18. Click synthesis of PET radiopharmaceuticals

    International Nuclear Information System (INIS)

    Xu Mei; Kuang Chunxiang

    2009-01-01

    Increasing attention has been focused on synthesis radiopharmaceuticals for positron emission tomography (PET). The recent years witnessed applications of click chemistry to PET radiopharmaceutical synthesis,because of its distinctive advantages including high speed,yield and stereospecificity under mild conditions. Synthesis of 18 F-labeled and 11 C-labeled radiopharmaceuticals and intermediates via click chemistry are reviewed. The future trend of click chemistry for the synthesis of PET radiopharmaceutical is prospected. (authors)

  19. PREVENTING CLICK EVENT HIJACKING BY USER INTENTION INFERENCE

    Directory of Open Access Journals (Sweden)

    Kailas Patil

    2016-12-01

    Full Text Available Web applications are getting more complex and dynamic. By exploiting layout and JavaScript features of a web page, attackers can create web page objects that hijack users’ clicks. Such objects look like normal web page objects, but users’ clicks on these objects lead to unexpected browser actions, such as visiting different URLs or sending out malicious requests. We call this type of attacks click event hijacking attacks. The Facebook Clickjacking attack is an example, which puts a transparent layer containing the victim web application on top of another web page that lures users to click. While users think they click on the underlying web page, they actually click in the victim web application, resulting in unauthorized actions to the web application. In this paper, we propose a solution to mitigate the problem of click event hijacking by inferring users’ intentions. Our solution ClickGuard ensures that the browser’s behavior after a click matches the user’s original intention. The proposed solution is implemented as a Mozilla Firefox extension and evaluated its effectiveness against click event hijacking attacks.

  20. AZIDE-ALKYNE CLICK POLYMERIZATION: AN UPDATE

    Institute of Scientific and Technical Information of China (English)

    Hong-kun Li; Jing-zhi Sun; An-jun Qin; Ben Zhong Tang

    2012-01-01

    The great achievements of click chemistry have encouraged polymer scientists to use this reaction in their field.This review assembles an update of the advances of using azide-alkyne click polymerization to prepare functional polytriazoles (PTAs) with linear and hyperbranched structures.The Cu(Ⅰ)-mediated click polymerization furnishes 1,4-regioregular PTAs,whereas,the metal-free click polymerization of propiolates and azides produces PTAs with 1,4-regioisomer contents up to 90%.The PTAs display advanced functions,such as aggregation-induced emission,thermal stability,biocompatibility and optical nonlinearity.

  1. Linking Metal Ions via Inorganic Click (iClick) Reactions

    Energy Technology Data Exchange (ETDEWEB)

    Veige, Adam [Univ. of Florida, Gainesville, FL (United States)

    2015-11-17

    This final report discusses the major objectives of the project, a discussion of the objectives achieved, a discussion of the objectives that failed, and finally, a discussion of future directions given the new knowledge obtained. This one-year seed project (with one year no-cost extension) contained three objectives: A) Expand the scope of iClick synthesis beyond AuI/AuI reactions. B) Elucidate a CuI-catalyzed iClick reaction. C) Synthesize and characterize tri- and tetra-metallic complexes as models for metallopolymers. Objectives A and C were achieved, whereas only parts of objective B were achieved.

  2. Compact Web browsing profiles for click-through rate prediction

    DEFF Research Database (Denmark)

    Fruergaard, Bjarne Ørum; Hansen, Lars Kai

    2014-01-01

    In real time advertising we are interested in finding features that improve click-through rate prediction. One source of available information is the bipartite graph of websites previously engaged by identifiable users. In this work, we investigate three different decompositions of such a graph...

  3. Ways to suppress click and pop for class D amplifiers

    International Nuclear Information System (INIS)

    Wang Haishi; Zhang Bo; Sun Jiang

    2012-01-01

    Undesirable audio click and pop may be generated in a speaker or headphone. Compared to linear (class A/B/AB) amplifiers, class D amplifiers that comprise of an input stage and a modulation stage are more prone to producing click and pop. This article analyzes sources that generate click and pop in class D amplifiers, and corresponding ways to suppress them. For a class D amplifier with a single-ended input, click and pop is likely to be due to two factors. One is from a voltage difference (V DIF ) between the voltage of an input capacitance (V CIN ) and a reference voltage (V REF ) of the input stage, and the other one is from the non-linear switching during the setting up of the bias and feedback voltages/currents (BFVC) of the modulation stage. In this article, a fast charging loop is introduced into the input stage to charge V CIN to roughly near V REF . Then a correction loop further charges or discharges V CIN , substantially equalizing it with V REF . Dummy switches are introduced into the modulation stage to provide switching signals for setting up BFVC, and the power switches are disabled until the BFVC are set up successfully. A two channel single-ended class D amplifier with the above features is fabricated with 0.5 μm Bi-CMOS process. Road test and fast Fourier transform analysis indicate that there is no noticeable click and pop. (semiconductor integrated circuits)

  4. Ways to suppress click and pop for class D amplifiers

    Science.gov (United States)

    Haishi, Wang; Bo, Zhang; Jiang, Sun

    2012-08-01

    Undesirable audio click and pop may be generated in a speaker or headphone. Compared to linear (class A/B/AB) amplifiers, class D amplifiers that comprise of an input stage and a modulation stage are more prone to producing click and pop. This article analyzes sources that generate click and pop in class D amplifiers, and corresponding ways to suppress them. For a class D amplifier with a single-ended input, click and pop is likely to be due to two factors. One is from a voltage difference (VDIF) between the voltage of an input capacitance (VCIN) and a reference voltage (VREF) of the input stage, and the other one is from the non-linear switching during the setting up of the bias and feedback voltages/currents (BFVC) of the modulation stage. In this article, a fast charging loop is introduced into the input stage to charge VCIN to roughly near VREF. Then a correction loop further charges or discharges VCIN, substantially equalizing it with VREF. Dummy switches are introduced into the modulation stage to provide switching signals for setting up BFVC, and the power switches are disabled until the BFVC are set up successfully. A two channel single-ended class D amplifier with the above features is fabricated with 0.5 μm Bi-CMOS process. Road test and fast Fourier transform analysis indicate that there is no noticeable click and pop.

  5. Think Before You Click

    CERN Multimedia

    2001-01-01

    Be aware of what attachments you open and what Internet programs you agree to download, the simple click of a mouse can be enough to introduce a virus at CERN and cause widespread damage. Modern viruses are a serious threat to our computers and networks. CERN limits the security risks that these programs pose through the use of its firewall, by constantly updating its anti-virus software, by detecting un-patched security holes, and by blocking many dangerous attachments as they pass through e-mail gateways, but these defenses do not guarantee 100% security. Our habits of clicking "ok" automatically on the Internet and opening attachments without thinking, are the behaviors that modern viruses are using to get past our security protections. Viruses can sit on the Internet waiting for us to activate them as we surf the web. Many of us simply click 'ok' when presented with dialogue boxes and this is exactly what the virus wants: clicking can be enough to download and infect our computers. Viruses can travel as...

  6. Temporal suppression of long-latency click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2007-01-01

    A comprehensive set of results from double click suppression experiments on otoacoustic emissions (OAEs) have been presented by Hine and Thornton (2002) and Kapadia and Lutman (2000). They found that suppression of a click-evoked otoacoustic emission (CEOAE) varied with the timing and level...... subjects showed that the nonlinear suppression effect remained on the long-latency CEOAE, indicating that both SOAEs and CEOAEs originate from the same cochlear nonlinearities, as earlier suggested by Kemp and Chum (1980). The apparent similar origin of both types of emissions implies that the same...

  7. Computer Security: one click and BOOM…

    CERN Multimedia

    Stefan Lueders, Computer Security Team

    2016-01-01

    Browsing the World Wide Web is not as easy as it seems… One wrong click and all your passwords (CERN, Facebook, PayPal, Amazon, etc.) could be stolen; all your activities could be clandestinely monitored (mouse movements and clicks, words typed, screenshots, microphone and webcam recordings, etc.); confidential documents could be stolen; and an attack path (a so-called back-door) into CERN could be opened…    As a result, you would have to reinstall your computer from scratch and change all your passwords! One of our colleagues learned this the hard way. One wrong click in summer 2015 permitted malicious attackers to infiltrate CERN but, fortunately, no real damage was done. Still, the cost of investigating the incident ran to several tens of thousands of Swiss francs and a lot of time was wasted trying to understand the attacker’s intent and the extent of the infiltration... With the goal of increasing more awareness of the risk of clicking on li...

  8. Click rates and silences of sperm whales at Kaikoura, New Zealand

    Science.gov (United States)

    Douglas, Lesley A.; Dawson, Stephen M.; Jaquet, Nathalie

    2005-07-01

    Analysis of the usual click rates of sperm whales (Physeter macrocephalus) at Kaikoura, New Zealand, confirms the potential for assessing abundance via ``click counting.'' Usual click rates over three dive cycles each of three photographically identified whales showed that 5 min averages of usual click rate did not differ significantly within dives, among dives of the same whale or among whales. Over the nine dives (n=13 728 clicks) mean usual click rate was 1.272 clicks s-1 (95% CI=0.151). On average, individual sperm whales at Kaikoura spent 60% of their time usual clicking in winter and in summer. There was no evidence that whale identity or stage of the dive recorded affects significantly the percentage of time spent usual clicking. Differences in vocal behavior among sperm whale populations worldwide indicate that estimates of abundance that are based on click rates need to based on data from the population of interest, rather than from another population or some global average.

  9. Intense Ultrasonic clicks from echolocating toothed whales do not elicit anti-predator responses or debilitate the squid Loligo pealeii

    DEFF Research Database (Denmark)

    Wilson, Maria; Hanlon, Roger; Tyack, Peter

    2007-01-01

    an evolutionary selection pressure on cephalopods to develop a mechanism for detecting and evading sound-emitting toothed whale predators. Ultrasonic detection has evolved in some insects to avoid echolocating bats, and it can be hypothesized that cephalopods might have evolved similar ultrasound detection...... as an anti-predation measure. We test this hypothesis in the squid Loligo pealeii in a playback experiment using intense echolocation clicks from two squid-eating toothed whale species. Twelve squid were exposed to clicks at two repetition rates (16 and 125 clicks per second) with received sound pressure...... levels of 199-226dBre1μPa (pp) mimicking the sound exposure from an echolocating toothed whale as it approaches and captures prey. We demonstrate that intense ultrasonic clicks do not elicit any detectable anti-predator behaviour in L. pealeii and that clicks with received levels up to 226dBre1μPa (pp...

  10. Click bait

    DEFF Research Database (Denmark)

    Blom, Jonas Nygaard; Reinecke Hansen, Kenneth

    2015-01-01

    and curiosity so the readers click (or tap on) the headline and read on. In this article, we map the use of forward-referring headlines in online news journalism by conducting an analysis of 100,000 headlines from 10 different Danish news websites. The results show that commercialization and tabloidization seem...

  11. Electronic health record innovations: Helping physicians - One less click at a time.

    Science.gov (United States)

    Guo, Uta; Chen, Lu; Mehta, Parag H

    2017-09-01

    Physician burnout is becoming an epidemic, due to the pressures of being productive, an imperfect electronic health record (EHR) system, and limited face-to-face time with patients. Poor usability in EHR-user interface can force users to go through more steps (i.e. more clicks on the computer) in accomplishing a task. This increased 'click burden' is a source of frustration for physicians. In the light of increased click burden and time due to meaningful use requirements, there is a need to improve the physician's experience by creating innovations in EHR. This case study describes an attempt by physicians at NewYork-Presbyterian Brooklyn Methodist Hospital to enhance the EHR experience with more efficient methods of documentation, chart review, ordering and patient safety. The EHR innovations trialled in this study were: a mobile documentation application; abnormal test results auto-populated into an EHR patient summary; physician alerts to reduce inappropriate test ordering; and a system of safety alerts on a dashboard. These innovations led to decreased click burden and allowed physicians to spend less time on the computer and more time with patients. Physician-driven changes to EHR systems have the potential to streamline virtual workflows and the management of health information and to improve patient safety, reduce physician burnout and increase physician job satisfaction.

  12. Temporal suppression and augmentation of click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2008-01-01

    This study investigates and models temporal suppression of click-evoked otoacoustic emissions (CEOAEs). This suppression-effect is created when a suppressor-click is presented close in time to a test-click. The analysis was carried out for short time-frames of short- and long-latency CEOAEs...... suppression is present in all CEOAEs for inter-click intervals (ICIs) less than 8 ms. The long-latency CEOAEs showed augmentation (i.e., negative suppression) for ICIs of 6-7 ms which was not reported for the short-latency CEOAE at these ICIs. A phenomenological approach is adopted here to explain both...

  13. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions

    Directory of Open Access Journals (Sweden)

    Youngsu Cha

    2016-07-01

    Full Text Available In this paper, we study energy harvesting from the mouse click motions of a robot finger and a human index finger using a piezoelectric material. The feasibility of energy harvesting from mouse click motions is experimentally and theoretically assessed. The fingers wear a glove with a pocket for including the piezoelectric material. We model the energy harvesting system through the inverse kinematic framework of parallel joints in a finger and the electromechanical coupling equations of the piezoelectric material. The model is validated through energy harvesting experiments in the robot and human fingers with the systematically varying load resistance. We find that energy harvesting is maximized at the matched load resistance to the impedance of the piezoelectric material, and the harvested energy level is tens of nJ.

  14. Clicks versus Citations: Click Count as a Metric in High Energy Physics Publishing

    Energy Technology Data Exchange (ETDEWEB)

    Bitton, Ayelet; /UC, San Diego /SLAC

    2011-06-22

    High-energy physicists worldwide rely on online resources such as SPIRES and arXiv to perform gather research and share their own publications. SPIRES is a tool designed to search the literature within high-energy physics, while arXiv provides the actual full-text documents of this literature. In high-energy physics, papers are often ranked according to the number of citations they acquire - meaning the number of times a later paper references the original. This paper investigates the correlation between the number of times a paper is clicked in order to be downloaded and the number of citations it receives following the click. It explores how physicists truly read what they cite.

  15. Synthesis of Diblock Codendrimer by Double Click Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Wook; Han, Seung Choul; Ji, Won Ho [Dong-A Univ., Busan (Korea, Republic of); Jin, Sungho [Pusan National Univ., Busan (Korea, Republic of); Kim, Ji Hyeon [Gachon Univ., Seongnam (Korea, Republic of)

    2012-12-15

    Efficient double click methods for the synthesis of diblock codendrimers were developed. The synthetic strategy involved the sequential click reactions between an alkyne and an azide. The short core building block, 1,4-diazidobutane, was chosen to serve as the azide functionalities for dendrimer growth via click reactions with the alkyne-functionalized PAMAM dendrons as hydrophilic dendron and alkyne-functionalized Frechet-type dendrons as hydrophobic dendron. The structure of diblock codendrimers was confirmed by {sup 1}H and {sup 13}C NMR spectroscopy, IR spectroscopy, mass spectrometry, and GPC analysis.

  16. Synthesis of Diblock Codendrimer by Double Click Chemistry

    International Nuclear Information System (INIS)

    Lee, Jae Wook; Han, Seung Choul; Ji, Won Ho; Jin, Sungho; Kim, Ji Hyeon

    2012-01-01

    Efficient double click methods for the synthesis of diblock codendrimers were developed. The synthetic strategy involved the sequential click reactions between an alkyne and an azide. The short core building block, 1,4-diazidobutane, was chosen to serve as the azide functionalities for dendrimer growth via click reactions with the alkyne-functionalized PAMAM dendrons as hydrophilic dendron and alkyne-functionalized Frechet-type dendrons as hydrophobic dendron. The structure of diblock codendrimers was confirmed by 1 H and 13 C NMR spectroscopy, IR spectroscopy, mass spectrometry, and GPC analysis

  17. Spectrogram analysis of low to mid frequency marine mammal clicks

    Science.gov (United States)

    Ioup, George E.; Ioup, Juliette W.; Larue, James P.; Sidorovskaia, Natalia A.; Kuczaj, Stan A.; Rayborn, Grayson H.; Walker, Christopher D.

    2004-05-01

    Previous investigators have proposed explanations for some sperm whale click structure and pointed out that the separation of individual pulses within the click might be used to determine approximately the size of the sperm whales. Recently, Mohl et al. [J. Acoust. Soc. Am. 114, 1124-1154 (2003)] have shown that echo-location click structure is highly dependent on the received angle. In data measured by the Littoral Acoustic Demonstration Center using bottom-moored hydrophones in the northern Gulf of Mexico in the summers of 2001 and 2002, rich click structures were observed in the spectrograms of many click trains, some of which exhibit strikingly consistent spectral nulls across the train. Although this structure in the spectra could be due to propagation effects, investigations to date suggest this possibility is highly unlikely, as discussed in the next abstract. Therefore it is at least plausible that the structure could be used to identify individual animals. This is known to be a difficult problem in the case of sperm whales because of the angle dependence of at least some of their clicks. These difficulties are discussed, as is the possible use of the spectrograms of the clicks to identify individuals. [Research supported by ONR.

  18. Cloning and characterization of luciferase from a Fijian luminous click beetle.

    Science.gov (United States)

    Mitani, Yasuo; Futahashi, Ryo; Niwa, Kazuki; Ohba, Nobuyoshi; Ohmiya, Yoshihiro

    2013-01-01

    Luminous click beetle is distributed almost exclusively in Central and South America with a single genus in Melanesia. Among these click beetles, the description of Melanesian species has been fragmentary, and its luciferase gene and phylogenetic relation to other click beetles still remain uncertain. We collected a living luminous click beetle, Photophorus jansonii in Fiji. It emits green-yellow light from two spots on the pronotum and has no ventral luminous organ. Here, we cloned a luciferase gene from this insect by RT-PCR. The deduced amino acid sequence showed high identity of ~85% to the luciferases derived from other click beetle species. The luciferase of the Fijian click beetle was produced as a recombinant protein to characterize its biochemical properties. The Km for D-luciferin and ATP were 173 and 270 μm, respectively. The luciferase was pH-insensitive and the spectrum measured at pH 8.0 showed a peak at 559 nm, which was in the range of green-yellow light as seen in the luminous spot of the living Fijian click beetle. The Fijian click beetle luciferase was assigned to the Elateridae clade by a phylogenetic analysis, but it made a clearly different branch from Pyrophorus group examined in this study. © 2013 The American Society of Photobiology.

  19. Temporal suppression and augmentation of click-evoked otoacoustic emissions

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten

    2008-01-01

    This study investigates temporal suppression of click-evoked otoacoustic emissions (CEOAEs), occurring when a suppressor-click is presented close in time to a test-click (e.g. 0-8ms). Various temporal suppression methods for examining temporal changes in cochlear compression were evaluated and me...... under test. Temporal suppression was shown to be comparable for CEOAEs and SSOAEs, indicating similar underlying cochlear nonlinear mechanisms. This study contributes to a better understanding of the temporal properties of cochlear dynamics....

  20. Harbor porpoise clicks do not have conditionally minimum time bandwidth product

    DEFF Research Database (Denmark)

    Beedholm, Kristian

    2008-01-01

    The hypothesis that odontocete clicks have minimal time frequency product given their delay and center frequency values is tested by using an in-phase averaged porpoise click compared with a pure tone weighted with the same envelope. These signals have the same delay and the same center frequency...... values but the time bandwidth product of the artificial click is only 0.76 that of the original. Therefore signals with the same parameters exist that have a lower time bandwidth product. The observation that porpoise clicks are in fact minimum phase is confirmed for porpoise clicks and this property...... is argued to be incompatible with optimal reception, if auditory filters are also minimum phase....

  1. Click Spam Prevention Model for Online Advertisement

    OpenAIRE

    Nicola Zingirian; Michele Benini

    2018-01-01

    This paper shows a vulnerability of the pay-per-click accounting of Google Ads and proposes a statistical tradeoff-based approach to manage this vulnerability. The result of this paper is a model to calculate the overhead cost per click necessary to protect the subscribers and a simple algorithm to implement this protection. Simulations validate the correctness of the model and the economical applicability.

  2. Brain stem auditory potentials evoked by clicks in the presence of high-pass filtered noise in dogs.

    Science.gov (United States)

    Poncelet, L; Deltenre, P; Coppens, A; Michaux, C; Coussart, E

    2006-04-01

    This study evaluates the effects of a high-frequency hearing loss simulated by the high-pass-noise masking method, on the click-evoked brain stem-evoked potentials (BAEP) characteristics in dogs. BAEP were obtained in response to rarefaction and condensation click stimuli from 60 dB normal hearing level (NHL, corresponding to 89 dB sound pressure level) to wave V threshold, using steps of 5 dB in eleven 58 to 80-day-old Beagle puppies. Responses were added, providing an equivalent to alternate polarity clicks, and subtracted, providing the rarefaction-condensation potential (RCDP). The procedure was repeated while constant level, high-pass filtered (HPF) noise was superposed to the click. Cut-off frequencies of the successively used filters were 8, 4, 2 and 1 kHz. For each condition, wave V and RCDP thresholds, and slope of the wave V latency-intensity curve (LIC) were collected. The intensity range at which RCDP could not be recorded (pre-RCDP range) was calculated. Compared with the no noise condition, the pre-RCDP range significantly diminished and the wave V threshold significantly increased when the superposed HPF noise reached the 4 kHz area. Wave V LIC slope became significantly steeper with the 2 kHz HPF noise. In this non-invasive model of high-frequency hearing loss, impaired hearing of frequencies from 8 kHz and above escaped detection through click BAEP study in dogs. Frequencies above 13 kHz were however not specifically addressed in this study.

  3. Learning of Multimodal Representations With Random Walks on the Click Graph.

    Science.gov (United States)

    Wu, Fei; Lu, Xinyan; Song, Jun; Yan, Shuicheng; Zhang, Zhongfei Mark; Rui, Yong; Zhuang, Yueting

    2016-02-01

    In multimedia information retrieval, most classic approaches tend to represent different modalities of media in the same feature space. With the click data collected from the users' searching behavior, existing approaches take either one-to-one paired data (text-image pairs) or ranking examples (text-query-image and/or image-query-text ranking lists) as training examples, which do not make full use of the click data, particularly the implicit connections among the data objects. In this paper, we treat the click data as a large click graph, in which vertices are images/text queries and edges indicate the clicks between an image and a query. We consider learning a multimodal representation from the perspective of encoding the explicit/implicit relevance relationship between the vertices in the click graph. By minimizing both the truncated random walk loss as well as the distance between the learned representation of vertices and their corresponding deep neural network output, the proposed model which is named multimodal random walk neural network (MRW-NN) can be applied to not only learn robust representation of the existing multimodal data in the click graph, but also deal with the unseen queries and images to support cross-modal retrieval. We evaluate the latent representation learned by MRW-NN on a public large-scale click log data set Clickture and further show that MRW-NN achieves much better cross-modal retrieval performance on the unseen queries/images than the other state-of-the-art methods.

  4. Applications of Azide-Based Bioorthogonal Click Chemistry in Glycobiology

    Directory of Open Access Journals (Sweden)

    Xiu Zhang

    2013-06-01

    Full Text Available Click chemistry is a powerful chemical reaction with excellent bioorthogonality features: biocompatible, rapid and highly specific in biological environments. For glycobiology, bioorthogonal click chemistry has created a new method for glycan non-invasive imaging in living systems, selective metabolic engineering, and offered an elite chemical handle for biological manipulation and glycomics studies. Especially the [3 + 2] dipolar cycloadditions of azides with strained alkynes and the Staudinger ligation of azides and triarylphosphines have been widely used among the extant click reactions. This review focuses on the azide-based bioorthogonal click chemistry, describing the characteristics and development of these reactions, introducing some recent applications in glycobiology research, especially in glycan metabolic engineering, including glycan non-invasive imaging, glycomics studies and viral surface manipulation for drug discovery as well as other applications like activity-based protein profiling and carbohydrate microarrays.

  5. The Click It or Ticket evaluation, 2012 : traffic safety facts : research note.

    Science.gov (United States)

    2014-03-01

    Click It or Ticket (CIOT) mobilizations are national, State, and local high-visibility enforcement (HVE) efforts designed to encourage motorists to buckle up. They have been conducted at the national level each year around Memorial Day since 2003. : ...

  6. Recent Advances in Click Chemistry Applied to Dendrimer Synthesis

    Directory of Open Access Journals (Sweden)

    Mathieu Arseneault

    2015-05-01

    Full Text Available Dendrimers are monodisperse polymers grown in a fractal manner from a central point. They are poised to become the cornerstone of nanoscale devices in several fields, ranging from biomedicine to light-harvesting. Technical difficulties in obtaining these molecules has slowed their transfer from academia to industry. In 2001, the arrival of the “click chemistry” concept gave the field a major boost. The flagship reaction, a modified Hüisgen cycloaddition, allowed researchers greater freedom in designing and building dendrimers. In the last five years, advances in click chemistry saw a wider use of other click reactions and a notable increase in the complexity of the reported structures. This review covers key developments in the click chemistry field applied to dendrimer synthesis from 2010 to 2015. Even though this is an expert review, basic notions and references have been included to help newcomers to the field.

  7. Click Bait: You Won’t Believe What Happens Next!

    Directory of Open Access Journals (Sweden)

    Liliana Alves

    2016-12-01

    Full Text Available The goal of this chapter is to investigate Click Bait, one of the strategies most commonly used by online news journalists aiming to make their headlines more attractive to readers. The chapter begins by studying Social Networks and the power they give marketers in spreading information. Next, a historical context to Click Bait is presented through its origins as Yellow Journalism, a 19th century journalism trend focused on hyperbolizing news headlines in order to increase sales. Finally, Click Bait is studied as the online application of techniques like Yellow Journalism. This section analyzes semantics and some of the most popular headline construction formulas. Literature on this matter concluded that the use of certain headline construction formulas yields significant increase in click-through rates. These increases could be beneficial to the publishing organization as they increase advertising impressions, but could also be detrimental, as these hyperbolic headlines may make readers feel manipulated.

  8. DNA barcoding of Japanese click beetles (Coleoptera, Elateridae).

    Science.gov (United States)

    Oba, Yuichi; Ôhira, Hitoo; Murase, Yukio; Moriyama, Akihiko; Kumazawa, Yoshinori

    2015-01-01

    Click beetles (Coleoptera: Elateridae) represent one of the largest groups of beetle insects. Some click beetles in larval form, known as wireworms, are destructive agricultural pests. Morphological identification of click beetles is generally difficult and requires taxonomic expertise. This study reports on the DNA barcoding of Japanese click beetles to enable their rapid and accurate identification. We collected and assembled 762 cytochrome oxidase subunit I barcode sequences from 275 species, which cover approximately 75% of the common species found on the Japanese main island, Honshu. This barcode library also contains 20 out of the 21 potential pest species recorded in Japan. Our analysis shows that most morphologically identified species form distinct phylogenetic clusters separated from each other by large molecular distances. This supports the general usefulness of the DNA barcoding approach for quick and reliable identification of Japanese elaterid species for environmental impact assessment, agricultural pest control, and biodiversity analysis. On the other hand, the taxonomic boundary in dozens of species did not agree with the boundary of barcode index numbers (a criterion for sequence-based species delimitation). These findings urge taxonomic reinvestigation of these mismatched taxa.

  9. DNA barcoding of Japanese click beetles (Coleoptera, Elateridae.

    Directory of Open Access Journals (Sweden)

    Yuichi Oba

    Full Text Available Click beetles (Coleoptera: Elateridae represent one of the largest groups of beetle insects. Some click beetles in larval form, known as wireworms, are destructive agricultural pests. Morphological identification of click beetles is generally difficult and requires taxonomic expertise. This study reports on the DNA barcoding of Japanese click beetles to enable their rapid and accurate identification. We collected and assembled 762 cytochrome oxidase subunit I barcode sequences from 275 species, which cover approximately 75% of the common species found on the Japanese main island, Honshu. This barcode library also contains 20 out of the 21 potential pest species recorded in Japan. Our analysis shows that most morphologically identified species form distinct phylogenetic clusters separated from each other by large molecular distances. This supports the general usefulness of the DNA barcoding approach for quick and reliable identification of Japanese elaterid species for environmental impact assessment, agricultural pest control, and biodiversity analysis. On the other hand, the taxonomic boundary in dozens of species did not agree with the boundary of barcode index numbers (a criterion for sequence-based species delimitation. These findings urge taxonomic reinvestigation of these mismatched taxa.

  10. Click Spam Prevention Model for On-Line Advertisement

    OpenAIRE

    Zingirian, Nicola; Benini, Michele

    2018-01-01

    This paper shows a vulnerability of the pay-per-click accounting of Google Ads and proposes a statistical tradeoff-based approach to manage this vulnerability. The result of this paper is a model to calculate the overhead cost per click necessary to protect the subscribers and a simple algorithm to implement this protection. Simulations validate the correctness of the model and the economical applicability.

  11. Pricing of on-line advertising: pay-per-view or pay-per-click?

    OpenAIRE

    Fjell, Kenneth

    2007-01-01

    We analyse the choice of pay-per-view (PPV) and price-per-click (PPC) when a web publisher is a price taker in the market for advertising banners, and the number of visits is decreasing in advertising. The main result is that the web publisher should always choose either PPV or PPC. If the click-through rate is exogenous, then the optimal amount of advertising is the same for both pricing metholds and the choice of pricing method is given by the click-through rate. If the click-through rate i...

  12. Functionalization of chitosan by click chemistry

    Science.gov (United States)

    Cheaburu-Yilmaz, Catalina Natalia; Karavana, Sinem Yaprak; Yilmaz, Onur

    2017-12-01

    Chitosan modification represents a challenge nowadays. The variety of compounds which can be obtained with various architectures and different functionalities made it attractive to be used in fields like pharmacy and material science. Presents study deals with the chemical modification of chitosan by using click chemistry technique. The study adopted the approach of clicking azidated chitosan with a synthesized alkyne terminated polymer i.e. poly N isopropylacrylamide with thermoresponsive properties. Structures were confirmed by the FT-IR and HNMR spectra. Thermal characterization was performed showing different thermal behaviour with the chemical modification. The final synthesized graft copolymer can play important role within pharmaceutical formulations carrying drugs for topical or oral treatments.

  13. Cows, clicks, ciphers, and satire

    Directory of Open Access Journals (Sweden)

    Tom Tyler

    2015-04-01

    Full Text Available The social network game Farmville, which allows players to grow crops, raise animals, and produce a variety of goods, proved enormously successful within a year of its launch in 2009, attracting 110 million Facebook users. However, the game has been criticised for its mindless mechanics, which require little more than repeated clicking on its colourful icons. By way of parody, Ian Bogost’s Cow Clicker permits its players to simply click on a picture of a cow once every six hours. In this essay I extend Bogost’s critique and suggest that Cow Clicker highlights not just the soulless inanity of Farmville gameplay but also the paucity of that game’s portrayal of the painful reality of a dairy cow’s punishing daily existence and untimely end.

  14. CuAAC-Based Click Chemistry in Self-Healing Polymers.

    Science.gov (United States)

    Döhler, Diana; Michael, Philipp; Binder, Wolfgang H

    2017-10-17

    Click chemistry has emerged as a significant tool for materials science, organic chemistry, and bioscience. Based on the initial concept of Barry Sharpless in 2001, the copper(I)-catalyzed azide/alkyne cycloaddition (CuAAC) reaction has triggered a plethora of chemical concepts for linking molecules and building blocks under ambient conditions, forming the basis for applications in autonomous cross-linking materials. Self-healing systems on the other hand are often based on mild cross-linking chemistries that are able to react either autonomously or upon an external trigger. In the ideal case, self-healing takes place efficiently at low temperatures, independent of the substrate(s) used, by forming strong and stable networks, binding to the newly generated (cracked) interfaces to restore the original material properties. The use of the CuAAC in self-healing systems, most of all the careful design of copper-based catalysts linked to additives as well as the chemical diversity of substrates, has led to an enormous potential of applications of this singular reaction. The implementation of click-based strategies in self-healing systems therefore is highly attractive, as here chemical (and physical) concepts of molecular reactivity, molecular design, and even metal catalysis are connected to aspects of materials science. In this Account, we will show how CuAAC reactions of multivalent components can be used as a tool for self-healing materials, achieving cross-linking at low temperatures (exploiting concepts of autocatalysis or internal chelation within the bulk CuAAC and systematic optimization of the efficiency of the used Cu(I) catalysts). Encapsulation strategies to separate the click components by micro- and nanoencapsulation are required in this context. Consequently, the examples reported here describe chemical concepts to realize more efficient and faster click reactions in self-healing polymeric materials. Thus, enhanced chain diffusion in (hyper

  15. Treatment Effects of Maxillary Flat Occlusal Splints for Painful Clicking of the Temporomandibular Joint

    Directory of Open Access Journals (Sweden)

    Sung-Wen Chang

    2010-06-01

    Full Text Available Existing therapies for symptoms related to painful clicking of the temporomandibular joint (TMJ have rarely met with complete success and predicting prognosis remains difficult. Few studies have reported the efficacy of maxillary flat occlusal splints (MFOSs for the treatment of painful clicking of the TMJ, and few studies have evaluated the predisposing factors that influence the clinical outcomes of MFOSs. The aim of this study was to investigate the treatment efficacy of MFOSs for painful clicking of the TMJ, and to determine the factors influencing TMJ therapy with MFOSs. We conducted a retrospective study of 109 patients suffering from unilateral clicking concurrent with preauricular area pain for at least 2 months between 2004 and 2008. Seventy-five patients were treated with an MFOS, while 34 patients did not receive MFOS therapy. Clicking score, pain-free maximal mouth opening, pain score, duration of the clicking sounds, age and bruxism were recorded during treatment and involved into the reviews. The degree of joint clicking was determined by a stethoscope placed in the anterolateral area of the external auditory canal and was divided into four grades. Data were analyzed using a Mann-Whitney U test, Fisher's exact test, and Student's t test. Results showed statistically significant differences in treatment outcomes between the MFOS-treated and control groups in clicking index, maximal mouth opening, pain and complete remission rates of symptoms within 1 year. Furthermore, for patients treated with MFOS, there were statistically significant differences in the clinical outcomes between those with a high clicking index and those with a low index before treatment. Factors significantly correlated with successful outcomes of MFOS included nocturnal bruxism, patient age and duration of clicking. MFOSs can be used to treat patients with painful clicking of the TMJ and related symptoms. The severity of clicking, bruxism, age and duration of

  16. Facile design of biomaterials by 'click' chemistry

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    2012-01-01

    The advent of the so‐called ‘click chemistry’ a decade ago has significantly improved the chemical toolbox for producing novel biomaterials. This review focuses primarily on the application of Cu(I)‐catalysed azide–alkyne 1,3‐cycloadditon in the preparation of numerous, diverse biomaterials...... chemistry is elaborated. The present state of creating functional and biologically active surfaces by click chemistry is presented. Finally, conducting surfaces based on an azide‐functionalized polymer with prospective biological sensor potential are introduced. Copyright © 2012 Society of Chemical Industry...

  17. Ukufundisa izicuku zeziqhakancu emagameni (Teaching click clusters in words

    Directory of Open Access Journals (Sweden)

    Gxowa-Dlayedwa, Ntombizodwa Cynthia

    2015-12-01

    Full Text Available Some teachers find it uninteresting and difficult to teach isiXhosa phonemes and syllables to grade one to three learners. This has a negative impact as the literacy results are low because learners’ reading and writing skills are poor. The linguistics terms featuring in the title, namely; consonants, vowels and syllables as found in words facilitate reading, and thus improve literacy standards in every language. IsiXhosa is one of the eleven official languages in South Africa. Phonemes include clicks and/or click cluster and vowels. On the other hand, there are people who are interested in learning to speak isiXhosa, but the difficulties encountered during the pronunciation of clicks discourage many of them. This study believes that the knowledge of phonemes and syllables will boost the literacy standard in isiXhosa. Therefore, the purposes of this study are to show that clicks and click clusters are found in major word categories which are in life circles. Secondly, if words are divided into segments, it becomes easy to produce them in print and reading skills. Thirdly, reading is possible in every language, and most importantly, skills are transferable. The current study therefore, argues that the knowledge of phonemes and syllables facilitates reading and creative writing skills. The data used in this study were taken from a novel written by Sidlayi (2009. Few examples have been given by the researchers themselves with an objective to clarify some ideas.

  18. Click it or ticket evaluation, 2008–2009 : traffic tech.

    Science.gov (United States)

    2013-06-01

    Click It or Ticket (CIOT) is a high-visibility enforcement : program to increase seat belt use. Click It or Ticket was : adopted as a national program in 2003 and is credited : with steady increases in seat belt use across the Nation. : In 2009, seat...

  19. Click-to-Chelate: Development of Technetium and Rhenium-Tricarbonyl Labeled Radiopharmaceuticals

    Directory of Open Access Journals (Sweden)

    Thomas L. Mindt

    2013-03-01

    Full Text Available The Click-to-Chelate approach is a highly efficient strategy for the radiolabeling of molecules of medicinal interest with technetium and rhenium-tricarbonyl cores. Reaction of azide-functionalized molecules with alkyne prochelators by the Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC; click reaction enables the simultaneous synthesis and conjugation of tridentate chelating systems for the stable complexation of the radiometals. In many cases, the functionalization of (biomolecules with the ligand system and radiolabeling can be achieved by convenient one-pot procedures. Since its first report in 2006, Click-to-Chelate has been applied to the development of numerous novel radiotracers with promising potential for translation into the clinic. This review summarizes the use of the Click-to-Chelate approach in radiopharmaceutical sciences and provides a perspective for future applications.

  20. Vocal reporting of echolocation targets: dolphins often report before click trains end.

    Science.gov (United States)

    Ridgway, S H; Elsberry, W R; Blackwood, D J; Kamolnick, T; Todd, M; Carder, D A; Chaplin, Monica; Cranford, T W

    2012-01-01

    Bottlenose dolphins (Tursiops truncatus) wore opaque suction cups over their eyes while stationing behind an acoustically opaque door. This put the dolphins in a known position and orientation. When the door opened, the dolphin clicked to detect targets. Trainers specified that Dolphin S emit a whistle if the target was a 7.5 cm water filled sphere, or a pulse burst if the target was a rock. S remained quiet if there was no target. Dolphin B whistled for the sphere. She remained quiet for rock and for no target. Thus, S had to choose between three different responses, whistle, pulse burst, or remain quiet. B had to choose between two different responses, whistle or remain quiet. S gave correct vocal responses averaging 114 ms after her last echolocation click (range 182 ms before and 219 ms after the last click). Average response for B was 21 ms before her last echolocation click (range 250 ms before and 95 ms after the last click in the train). More often than not, B began her whistle response before her echolocation train ended. The findings suggest separate neural pathways for generation of response vocalizations as opposed to echolocation clicks. © 2012 Acoustical Society of America.

  1. General Dialdehyde Click Chemistry for Amine Bioconjugation.

    Science.gov (United States)

    Elahipanah, Sina; O'Brien, Paul J; Rogozhnikov, Dmitry; Yousaf, Muhammad N

    2017-05-17

    The development of methods for conjugating a range of molecules to primary amine functional groups has revolutionized the fields of chemistry, biology, and material science. The primary amine is a key functional group and one of the most important nucleophiles and bases used in all of synthetic chemistry. Therefore, tremendous interest in the synthesis of molecules containing primary amines and strategies to devise chemical reactions to react with primary amines has been at the core of chemical research. In particular, primary amines are a ubiquitous functional group found in biological systems as free amino acids, as key side chain lysines in proteins, and in signaling molecules and metabolites and are also present in many natural product classes. Due to its abundance, the primary amine is the most convenient functional group handle in molecules for ligation to other molecules for a broad range of applications that impact all scientific fields. Because of the primary amine's central importance in synthetic chemistry, acid-base chemistry, redox chemistry, and biology, many methods have been developed to efficiently react with primary amines, including activated carboxylic acids, isothiocyanates, Michael addition type systems, and reaction with ketones or aldehydes followed by in situ reductive amination. Herein, we introduce a new traceless, high-yield, fast click-chemistry method based on the rapid and efficient trapping of amine groups via a functionalized dialdehyde group. The click reaction occurs in mild conditions in organic solvents or aqueous media and proceeds in high yield, and the starting dialdehyde reagent and resulting dialdehyde click conjugates are stable. Moreover, no catalyst or dialdehyde-activating group is required, and the only byproduct is water. The initial dialdehyde and the resulting conjugate are both straightforward to characterize, and the reaction proceeds with high atom economy. To demonstrate the broad scope of this new click

  2. Click It or Ticket Evaluation, 2011

    Science.gov (United States)

    2013-05-01

    The 2011 Click It or Ticket (CIOT) mobilization followed a typical selective traffic enforcement program (STEP) sequence, involving paid media, earned media, and enforcement. A nationally representative telephone survey indicated that the mobilizatio...

  3. Click It or Ticket Evaluation, 2010

    Science.gov (United States)

    2013-05-01

    The 201 Click It or Ticket (CIOT) mobilization followed a typical elective traffic enforcement program TEP) sequence, involving paid media, earned media, and enforcement. A nationally representative telephone survey indicated that the mobilization wa...

  4. Ionic liquid syntheses via click chemistry: expeditious routes toward versatile functional materials.

    Science.gov (United States)

    Mirjafari, Arsalan

    2018-03-25

    Since the introduction of click chemistry by K. B. Sharpless in 2001, its exploration and exploitation has occurred in countless fields of materials sciences in both academic and industrial spheres. Click chemistry is defined as an efficient, robust, and orthogonal synthetic platform for the facile formation of new carbon-heteroatom bonds, using readily available starting materials. Premier examples of click reactions are copper(i)-catalyzed azide-alkyne Huisgen cycloaddition (CuAAC) and the thiol-X (X = ene and yne) coupling reactions to form C-N and C-S bonds, respectively. The emphasis of this review is centered on the rapidly expanding area of click chemistry-mediated synthesis of functional ionic liquids via CuAAC, thiol-X and oxime formation, and selected examples of nucleophilic ring-opening reactions, while offering some thoughts on emerging challenges, opportunities and ultimately the evolution of this field. Click chemistry offers tremendous opportunities, and introduces intriguing perspectives for efficient and robust generation of tailored task-specific ionic liquids - an important class of soft materials.

  5. An API-based search system for one click access to information

    NARCIS (Netherlands)

    Ionita, Dan; Tax, Niek; Hiemstra, Djoerd

    This paper proposes a prototype One Click access system, based on previous work in the field and the related 1CLICK-2@NTCIR10 task. The proposed solution integrates methods from into a three tier algorithm: query categorization, information extraction and output generation and offers suggestions on

  6. Assessing segmentation processes by click detection: online measure of statistical learning, or simple interference?

    Science.gov (United States)

    Franco, Ana; Gaillard, Vinciane; Cleeremans, Axel; Destrebecqz, Arnaud

    2015-12-01

    Statistical learning can be used to extract the words from continuous speech. Gómez, Bion, and Mehler (Language and Cognitive Processes, 26, 212-223, 2011) proposed an online measure of statistical learning: They superimposed auditory clicks on a continuous artificial speech stream made up of a random succession of trisyllabic nonwords. Participants were instructed to detect these clicks, which could be located either within or between words. The results showed that, over the length of exposure, reaction times (RTs) increased more for within-word than for between-word clicks. This result has been accounted for by means of statistical learning of the between-word boundaries. However, even though statistical learning occurs without an intention to learn, it nevertheless requires attentional resources. Therefore, this process could be affected by a concurrent task such as click detection. In the present study, we evaluated the extent to which the click detection task indeed reflects successful statistical learning. Our results suggest that the emergence of RT differences between within- and between-word click detection is neither systematic nor related to the successful segmentation of the artificial language. Therefore, instead of being an online measure of learning, the click detection task seems to interfere with the extraction of statistical regularities.

  7. Click nucleic acid ligation: applications in biology and nanotechnology.

    Science.gov (United States)

    El-Sagheer, Afaf H; Brown, Tom

    2012-08-21

    Biochemical strategies that use a combination of synthetic oligonucleotides, thermostable DNA polymerases, and DNA ligases can produce large DNA constructs up to 1 megabase in length. Although these ambitious targets are feasible biochemically, comparable technologies for the chemical synthesis of long DNA strands lag far behind. The best available chemical approach is the solid-phase phosphoramidite method, which can be used to assemble DNA strands up to 150 bases in length. Beyond this point, deficiencies in the chemistry make it impossible to produce pure DNA. A possible alternative approach to the chemical synthesis of large DNA strands is to join together carefully purified synthetic oligonucleotides by chemical methods. Click ligation by the copper-catalyzed azide-alkyne (CuAAC) reaction could facilitate this process. In this Account, we describe the synthesis, characterization, and applications of oligonucleotides prepared by click ligation. The alkyne and azide oligonucleotide strands can be prepared by standard protocols, and the ligation reaction is compatible with a wide range of chemical modifications to DNA and RNA. We have employed click ligation to synthesize DNA constructs up to 300 bases in length and much longer sequences are feasible. When the resulting triazole linkage is placed in a PCR template, various DNA polymerases correctly copy the entire base sequence. We have also successfully demonstrated both in vitro transcription and rolling circle amplification through the modified linkage. This linkage has shown in vivo biocompatibility: an antibiotic resistance gene containing triazole linkages functions in E. coli . Using click ligation, we have synthesized hairpin ribozymes up to 100 nucleotides in length and a hammerhead ribozyme with the triazole linkage located at the substrate cleavage site. At the opposite end of the length scale, click-ligated, cyclic mini-DNA duplexes have been used as models to study base pairing. Cyclic duplexes have

  8. Aiming and clicking in young children's use of the computer mouse

    NARCIS (Netherlands)

    Donker, A.; Reitsma, P.

    2007-01-01

    The present study investigated the abilities of young children to aim and click with a computer mouse. Young children have not yet fully developed their motor skills and they are therefore more likely than adults to click next to targets on the computer screen. Because in educational software

  9. Complex Surface Concentration Gradients by Stenciled "Electro Click Chemistry"

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede

    2010-01-01

    Complex one- or two-dimensional concentration gradients of alkynated molecules are produced on azidized conducting polymer substrates by stenciled "electro click chemistry". The latter describes the local electrochemical generation of catalytically active Cu(I) required to complete a "click...... reaction" between alkynes and azides at room temperature. A stencil on the counter electrode defines the shape and multiplicity of the gradient(s) on the conducting polymer substrate, while the specific reaction conditions control gradient steepness and the maximum concentration deposited. Biologically...

  10. Improving Web Page Retrieval using Search Context from Clicked Domain Names

    NARCIS (Netherlands)

    Li, R.

    Search context is a crucial factor that helps to understand a user’s information need in ad-hoc Web page retrieval. A query log of a search engine contains rich information on issued queries and their corresponding clicked Web pages. The clicked data implies its relevance to the query and can be

  11. Synthesis of hydrogel via click chemistry for DNA electrophoresis.

    Science.gov (United States)

    Finetti, Chiara; Sola, Laura; Elliott, Jim; Chiari, Marcella

    2017-09-01

    This work introduces a novel sieving gel for DNA electrophoresis using a classical click chemistry reaction, the copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC), to cross-link functional polymer chains. The efficiency of this reaction provides, under mild conditions, hydrogels with near-ideal network connectivity and improved physical properties. Hydrogel formation via click chemistry condensation of functional polymers does not involve the use of toxic monomers and UV initiation. The performance of the new hydrogel in the separation of double stranded DNA fragments was evaluated in the 2200 TapeStation system, an analytical platform, recently introduced by Agilent that combines the advantages of CE in terms of miniaturization and automation with the simplicity of use of slab gel electrophoresis. The click gel enables addition of florescent dyes prior to electrophoresis with considerable improvement of resolution and separation efficiency over conventional cross-linked polyacrylamide gels. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Deteção de anomalias em modelos de publicidade Pay-Per-Click

    OpenAIRE

    Lopes, Eduardo Luís da Silva

    2012-01-01

    Dissertação de mestrado em Engenharia Informática Nowadays, online advertisement is one of the most effective and profitable marketing strategies. An example of strong growth in online advertisement is the Pay-Per-Click Advertising Model where all parties are benefited. Due to the number of stakeholders and the amount of money involved, it is inevitable to find efficient methods to analyse the validity of clicks on online advertising, specifically in Pay-Per-Click. The co...

  13. In situ visualization of newly synthesized proteins in environmental microbes using amino acid tagging and click chemistry

    Science.gov (United States)

    Hatzenpichler, Roland; Scheller, Silvan; Tavormina, Patricia L; Babin, Brett M; Tirrell, David A; Orphan, Victoria J

    2014-01-01

    Here we describe the application of a new click chemistry method for fluorescent tracking of protein synthesis in individual microorganisms within environmental samples. This technique, termed bioorthogonal non-canonical amino acid tagging (BONCAT), is based on the in vivo incorporation of the non-canonical amino acid L-azidohomoalanine (AHA), a surrogate for l-methionine, followed by fluorescent labelling of AHA-containing cellular proteins by azide-alkyne click chemistry. BONCAT was evaluated with a range of phylogenetically and physiologically diverse archaeal and bacterial pure cultures and enrichments, and used to visualize translationally active cells within complex environmental samples including an oral biofilm, freshwater and anoxic sediment. We also developed combined assays that couple BONCAT with ribosomal RNA (rRNA)-targeted fluorescence in situ hybridization (FISH), enabling a direct link between taxonomic identity and translational activity. Using a methanotrophic enrichment culture incubated under different conditions, we demonstrate the potential of BONCAT-FISH to study microbial physiology in situ. A direct comparison of anabolic activity using BONCAT and stable isotope labelling by nano-scale secondary ion mass spectrometry (15NH3 assimilation) for individual cells within a sediment-sourced enrichment culture showed concordance between AHA-positive cells and 15N enrichment. BONCAT-FISH offers a fast, inexpensive and straightforward fluorescence microscopy method for studying the in situ activity of environmental microbes on a single-cell level. PMID:24571640

  14. Nanofabrication Yields. Hybridization and Click-Fixation of Polycyclic DNA Nanoassemblies

    KAUST Repository

    Lundberg, Erik P.

    2011-09-27

    We demonstrate the stepwise assembly of a fully addressable polycyclic DNA hexagon nanonetwork for the preparation of a four-ring system, one of the biggest networks yet constructed from tripodal building blocks. We find that the yield exhibits a distinct upper level <100%, a fundamental problem of thermodynamic DNA assembly that appears to have been overlooked in the DNA nanotechnology literature. A simplistic model based on a single step-yield parameter y can quantitatively describe the total yield of DNA assemblies in one-pot reactions as Y = yduplex n, with n the number of hybridization steps. Experimental errors introducing deviations from perfect stoichiometry and the thermodynamics of hybridization equilibria contribute to decreasing the value of yduplex (on average y = 0.96 for our 10 base pair hybridization). For the four-ring system (n = 31), the total yield is thus less than 30%, which is clearly unsatisfactory if bigger nanoconstructs of this class are to be designed. Therefore, we introduced site-specific click chemistry for making and purifying robust building blocks for future modular constructs of larger assemblies. Although the present yield of this robust module was only about 10%, it demonstrates a first step toward a general fabrication approach. Interestingly, we find that the click yields follow quantitatively a binomial distribution, the predictability of which indicates the usefulness of preparing pools of pure and robust building blocks in this way. The binomial behavior indicates that there is no interference between the six simultaneous click reactions but that step-yield limiting factors such as topological constraints and Cu(I) catalyst concentration are local and independent. © 2011 American Chemical Society.

  15. All in the family: matrimonial mitral valve clicks.

    Science.gov (United States)

    Desser, K B; Bokhari, S I; Benchimol, A; Romney, D

    1981-05-01

    Mitral valve clicks with or without late systolic murmurs were detected in genetically unrelated marital partners of 5 families. The first family represented 2 successive nonconsanguineous marital unions with 3 generations of mitral valve clicks. The second family included 1 natural and 2 adopted children with clinical and echographic evidence of mitral valve prolapse. The third family was comprised of asymptomatic parents, both with nonejection clicks and mitral valve prolapse, whose daughter presented 3 years previously with syncope, palpitations, and combined mitral and tricuspid valve prolapse. The fourth family had 3 members with auscultatory and ultrasonic manifestations of billowing mitral valve, whereas the fourth member had "silent mitral valve prolapse." The fifth family represented a mother with auscultatory and echographic evidence of mitral valve prolapse; her 14-year-old daughter had both mitral and tricuspid valve prolapse, whereas the son had a bicuspid aortic valve. Both children were products of a prior marriage, and her husband has symptomatic mitral valve prolapse. We conclude that matrimonial mitral valve prolapse probably reflects the purported (6--10%) prevalence of this disorder in the general population. The consequences of such marital union on progeny is currently unclear and warrants future investigation.

  16. Conductive Polymer Functionalization by Click Chemistry

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hvilsted, Søren; Hansen, Thomas Steen

    2008-01-01

    Click chemistry is used to obtain new conductive polymer films based on poly(3,4-ethylenedioxythiophene) (PEDOT) from a new azide functional monomer. Postpolymerization, 1,3-dipolar cycloadditions in DMF, using a catalyst system of CUS04 and sodium ascorbate, and different alkynes are performed...

  17. The digital laser: on-demand laser modes with the click of a button

    CSIR Research Space (South Africa)

    Forbes, A

    2014-02-01

    Full Text Available stream_source_info Forbes_2014_ABSTRACT ONLY.pdf.txt stream_content_type text/plain stream_size 729 Content-Encoding UTF-8 stream_name Forbes_2014_ABSTRACT ONLY.pdf.txt Content-Type text/plain; charset=UTF-8 The digital... laser: on-demand laser modes with the click of a button Forbes A, Ngcobo S, Burger L and Litvin IA ABSTRACT In this paper we will outline our recent advances in all-digital control of light. Importantly, we will outline how to create a so...

  18. Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder

    NARCIS (Netherlands)

    Burke, Sarah M; Menks, Willeke M; Cohen-Kettenis, Peggy T; Klink, Daniel T; Bakker, J.

    2014-01-01

    Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to

  19. Click-Evoked Otoacoustic Emissions in Children and Adolescents with Gender Identity Disorder

    NARCIS (Netherlands)

    Burke, S.M.; Menks, W.M.; Cohen-Kettenis, P.T.; Klink, D.T.; Bakker, J.

    2014-01-01

    Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to

  20. Electrochemical Power Sources

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Electrochemical Power Sources - Rechargeable Batteries. A K Shukla S K Martha. General Article Volume 6 Issue 7 July 2001 pp 52-63. Fulltext. Click here to view fulltext PDF. Permanent link:

  1. Click It or Ticket evaluation : 2008-2009.

    Science.gov (United States)

    2013-06-01

    Click It or Ticket (CIOT) mobilizations are intense, short-duration, widely publicized enforcement efforts used to improve seat belt use. Annual national mobilizations have been conducted in May every year since 2003. National and State expenditures ...

  2. VeriClick: an efficient tool for table format verification

    Science.gov (United States)

    Nagy, George; Tamhankar, Mangesh

    2012-01-01

    The essential layout attributes of a visual table can be defined by the location of four critical grid cells. Although these critical cells can often be located by automated analysis, some means of human interaction is necessary for correcting residual errors. VeriClick is a macro-enabled spreadsheet interface that provides ground-truthing, confirmation, correction, and verification functions for CSV tables. All user actions are logged. Experimental results of seven subjects on one hundred tables suggest that VeriClick can provide a ten- to twenty-fold speedup over performing the same functions with standard spreadsheet editing commands.

  3. Deep Multimodal Distance Metric Learning Using Click Constraints for Image Ranking.

    Science.gov (United States)

    Yu, Jun; Yang, Xiaokang; Gao, Fei; Tao, Dacheng

    2017-12-01

    How do we retrieve images accurately? Also, how do we rank a group of images precisely and efficiently for specific queries? These problems are critical for researchers and engineers to generate a novel image searching engine. First, it is important to obtain an appropriate description that effectively represent the images. In this paper, multimodal features are considered for describing images. The images unique properties are reflected by visual features, which are correlated to each other. However, semantic gaps always exist between images visual features and semantics. Therefore, we utilize click feature to reduce the semantic gap. The second key issue is learning an appropriate distance metric to combine these multimodal features. This paper develops a novel deep multimodal distance metric learning (Deep-MDML) method. A structured ranking model is adopted to utilize both visual and click features in distance metric learning (DML). Specifically, images and their related ranking results are first collected to form the training set. Multimodal features, including click and visual features, are collected with these images. Next, a group of autoencoders is applied to obtain initially a distance metric in different visual spaces, and an MDML method is used to assign optimal weights for different modalities. Next, we conduct alternating optimization to train the ranking model, which is used for the ranking of new queries with click features. Compared with existing image ranking methods, the proposed method adopts a new ranking model to use multimodal features, including click features and visual features in DML. We operated experiments to analyze the proposed Deep-MDML in two benchmark data sets, and the results validate the effects of the method.

  4. Click Chemistry for the Synthesis of RGD-Containing Integrin Ligands

    Directory of Open Access Journals (Sweden)

    Matteo Colombo

    2010-01-01

    Full Text Available In the last few years click chemistry reactions, and in particular coppercatalyzed cycloadditions, have been used intensively for the preparation of new bioconjugate molecules and materials applicable to biomedical and pharmaceutical areas. This review will be focused on conjugates of the tripeptide Arg-Gly-Asp formed by means of click chemistry reactions. This sequence is a well known binding motif for specific transmembrane proteins and is involved in cellular adhesion to the extracellular matrix, allowing the selective recognition of the biomolecule or polymer in which it is incorporated.

  5. Comparative Analysis of Click Chemistry Mediated Activity-Based Protein Profiling in Cell Lysates

    Directory of Open Access Journals (Sweden)

    Yinliang Yang

    2013-10-01

    Full Text Available Activity-based protein profiling uses chemical probes that covalently attach to active enzyme targets. Probes with conventional tags have disadvantages, such as limited cell permeability or steric hindrance around the reactive group. A tandem labeling strategy with click chemistry is now widely used to study enzyme targets in situ and in vivo. Herein, the probes are reacted in live cells, whereas the ensuing detection by click chemistry takes place in cell lysates. We here make a comparison of the efficiency of the activity-based tandem labeling strategy by using Cu(I-catalyzed and strain-promoted click chemistry, different ligands and different lysis conditions.

  6. Directionality of sperm whale sonar clicks and its relation to piston radiation theory

    DEFF Research Database (Denmark)

    Beedholm, K.; Møhl, Bertel

    2006-01-01

    This paper investigates the applicability to sperm whales of the theory of sound radiating from a piston. The theory is applied to a physical model and to a series of sperm whale clicks. Results show that wave forms of off-axis signals can be reproduced by convolving an on-axis signal...... with the spatial impulse response of a piston. The angle of a recorded click can be estimated as the angle producing the spatial impulse response that gives the best match with the observation when convolved with the on-axis wave form. It is concluded that piston theory applies to sperm whale sonar click emission....

  7. Medclic: the Mediterranean in one click

    Science.gov (United States)

    Troupin, Charles; Frontera, Biel; Sebastián, Kristian; Pau Beltran, Joan; Krietemeyer, Andreas; Gómara, Sonia; Gomila, Mikel; Escudier, Romain; Juza, Mélanie; Mourre, Baptiste; Garau, Angels; Cañellas, Tomeu; Tintoré, Joaquín

    2016-04-01

    "Medclic: the Mediterranean in one click" is a research and dissemination project focused on the scientific, technological and societal approaches of the Balearic Islands Coastal Observing and Forecasting System ({SOCIB}{www.socib.es}) in a collaboration with "la Caixa" Foundation. SOCIB aims at research excellence and the development of technology which enables progress toward the sustainable management of coastal and marine environments, providing solutions to meet the needs of society. Medclic goes one step forward and has two main goals: at the scientific level, to advance in establishing and understanding the mesoscale variability at the regional scale and its interaction, and thus improving the characterisation of the "oceanic weather" in the Mediterranean; at the outreach level: to bring SOCIB and the new paradigm of multi-platform observation in real time closer to society, through scientific outreach. SOCIB Data Centre is the core of the new multi-platform and real time oceanography and is responsible for directing the different stages of data management, ranging from data acquisition to its distribution and visualization through web applications. The system implemented relies on open source solutions and provides data in line with international standards and conventions (INSPIRE, netCDF Climate and Forecast, ldots). In addition, the Data Centre has implemented a REST web service, called Data Discovery. This service allows data generated by SOCIB to be integrated into applications developed by the Data Centre itself or by third parties, as it is the case with Medclic. Relying on this data distribution, the new web Medclic, www.medclic.es, constitutes an interactive scientific and educational area of communication that contributes to the rapprochement of the general public with the new marine and coastal observing technologies. Thanks to the Medclic web, data coming from new observing technologies in oceanography are available in real time and in one clic

  8. Click hydrogels, microgels and nanogels: emerging platforms for drug delivery and tissue engineering.

    Science.gov (United States)

    Jiang, Yanjiao; Chen, Jing; Deng, Chao; Suuronen, Erik J; Zhong, Zhiyuan

    2014-06-01

    Hydrogels, microgels and nanogels have emerged as versatile and viable platforms for sustained protein release, targeted drug delivery, and tissue engineering due to excellent biocompatibility, a microporous structure with tunable porosity and pore size, and dimensions spanning from human organs, cells to viruses. In the past decade, remarkable advances in hydrogels, microgels and nanogels have been achieved with click chemistry. It is a most promising strategy to prepare gels with varying dimensions owing to its high reactivity, superb selectivity, and mild reaction conditions. In particular, the recent development of copper-free click chemistry such as strain-promoted azide-alkyne cycloaddition, radical mediated thiol-ene chemistry, Diels-Alder reaction, tetrazole-alkene photo-click chemistry, and oxime reaction renders it possible to form hydrogels, microgels and nanogels without the use of potentially toxic catalysts or immunogenic enzymes that are commonly required. Notably, unlike other chemical approaches, click chemistry owing to its unique bioorthogonal feature does not interfere with encapsulated bioactives such as living cells, proteins and drugs and furthermore allows versatile preparation of micropatterned biomimetic hydrogels, functional microgels and nanogels. In this review, recent exciting developments in click hydrogels, microgels and nanogels, as well as their biomedical applications such as controlled protein and drug release, tissue engineering, and regenerative medicine are presented and discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Heat-induced-radiolabeling and click chemistry: A powerful combination for generating multifunctional nanomaterials.

    Directory of Open Access Journals (Sweden)

    Hushan Yuan

    Full Text Available A key advantage of nanomaterials for biomedical applications is their ability to feature multiple small reporter groups (multimodality, or combinations of reporter groups and therapeutic agents (multifunctionality, while being targeted to cell surface receptors. Here a facile combination of techniques for the syntheses of multimodal, targeted nanoparticles (NPs is presented, whereby heat-induced-radiolabeling (HIR labels NPs with radiometals and so-called click chemistry is used to attach bioactive groups to the NP surface. Click-reactive alkyne or azide groups were first attached to the nonradioactive clinical Feraheme (FH NPs. Resulting "Alkyne-FH" and "Azide-FH" intermediates, like the parent NP, tolerated 89Zr labeling by the HIR method previously described. Subsequently, biomolecules were quickly conjugated to the radioactive NPs by either copper-catalyzed or copper-free click reactions with high efficiency. Synthesis of the Alkyne-FH or Azide-FH intermediates, followed by HIR and then by click reactions for biomolecule attachment, provides a simple and potentially general path for the synthesis of multimodal, multifunctional, and targeted NPs for biomedical applications.

  10. Are occlusal characteristics, headache, parafunctional habits and clicking sounds associated with the signs and symptoms of temporomandibular disorder in adolescents?

    Science.gov (United States)

    Lauriti, Leandro; Motta, Lara Jansiski; Silva, Paula Fernanda da Costa; Leal de Godoy, Camila Haddad; Alfaya, Thays Almeida; Fernandes, Kristianne Porta Santos; Mesquita-Ferrari, Raquel Agnelli; Bussadori, Sandra Kalil

    2013-10-01

    [Purpose] To assess the association between the oclusal characteristics, headache, parafunctional habits and clicking sounds and signs/symptoms of TMD in adolescents. [Subjects] Adolescents between 14 and 18 years of age. [Methods] The participants were evaluated using the Helkimo Index and a clinical examination to track clicking sounds, parafunctional habits and other signs/symptoms of temporomandibular disorder (TMD). Subjects were classified according to the presence or absence of headache, type of occlusion, facial pattern and type of bite. In statistical analyse we used the chi-square test and Fisher's exact test, with a level of significance of 5%. [Results] The sample was made up of 81 adolescents with a mean age of 15.64 years; 51.9% were male. The prevalence of signals/symptoms of TMD was 74.1%, predominantly affecting females. Signals/symptoms of TMD were significantly associated with clicking sounds, headache and nail biting. No associations were found between signals/symptoms of TMD and angle classification, type of bite and facial pattern. [Conclusion] Headache is one of the most closely associated symptoms of TMD. Clicking sounds were found in the majority of cases. Therefore, the sum of two or more factors may be necessary for the onset and perpetuation of TMD.

  11. Integrating Click-Through and Eye-Tracking Logs for Decision-Making Process Mining

    Directory of Open Access Journals (Sweden)

    Razvan PETRUSEL

    2014-01-01

    Full Text Available In current software every click of the users is logged, therefore a wealth of click-through information exists. Besides, recent technologies have made eye-tracking affordable and an alternative to other human-computer interaction means (e.g. mouse, touchscreens. A big challenge is to make sense of all this data and convert it into useful information. This paper introduces a possible solution placed in the context of decision-making processes. We show how the decision maker's activity can be traced using two means: mouse tracing (i.e. clicks and eye-tracking (i.e. eye fixations. Then, we discuss a mining approach, based on the log, which extracts a Decision Data Model (DDM. We use the DDM to determine, post-hoc, which decision strategy was employed. The paper concludes with a validation based on a controlled experiment.

  12. Modification of chemical and conformational properties of natural organic matter by click chemistry as revealed by ESI-Orbitrap mass spectrometry.

    Science.gov (United States)

    Nebbioso, Antonio; Piccolo, Alessandro

    2015-11-01

    A click reaction is reported here for the first time as a useful technique to control the conformational stability of natural organic matter (NOM) suprastructures. Click conjugates were successfully formed between a previously butynylated NOM hydrophobic fraction and a hydrophilic polyethylene glycol (PEG)-amino chain. The click products were shown by size exclusion chromatography (HPSEC) hyphenated with Orbitrap mass spectrometry (MS) in electrospray ionization (ESI) (+), while precursors were visible in ESI (-). Despite their increase in molecular weight, HPSEC elution of click conjugates occurred after that of precursors, thus showing their departure from the NOM supramolecular association. This indicates that the click-conjugated NOM molecules were varied in their hydrophilic and cationic character and lost the capacity to accommodate in the original hydrophobic suprastructures. The most abundant product had the C16H30O5N4 formula, a click conjugate of butanoic acid, while other products were short-chained (C4-C8) linear unsaturated and hydroxylated carboxylic acids. Tandem MS revealed formation of triazole rings in clicked conjugates and their two fragmentations at the ester and the C-N alkyl-aryl bonds. The behavior of NOM molecules modified by click chemistry confirms that hydrophobicity and ionic charge of humic molecules play a pivotal role in stabilizing intermolecular forces in NOM. Moreover, the versatility of the click reaction may become useful to decorate NOM molecules with a variety of substrates, in order to alter NOM conformational and chemical properties and diversify its applications in the environment.

  13. Estimating Ads’ Click through Rate with Recurrent Neural Network

    Directory of Open Access Journals (Sweden)

    Chen Qiao-Hong

    2016-01-01

    Full Text Available With the development of the Internet, online advertising spreads across every corner of the world, the ads' click through rate (CTR estimation is an important method to improve the online advertising revenue. Compared with the linear model, the nonlinear models can study much more complex relationships between a large number of nonlinear characteristics, so as to improve the accuracy of the estimation of the ads’ CTR. The recurrent neural network (RNN based on Long-Short Term Memory (LSTM is an improved model of the feedback neural network with ring structure. The model overcomes the problem of the gradient of the general RNN. Experiments show that the RNN based on LSTM exceeds the linear models, and it can effectively improve the estimation effect of the ads’ click through rate.

  14. Specific Labeling of Zinc Finger Proteins using Non-canonical Amino Acids and Copper-free Click Chemistry

    Science.gov (United States)

    Kim, Younghoon; Kim, Sung Hoon; Ferracane, Dean; Katzenellenbogen, John A.

    2012-01-01

    Zinc finger proteins (ZFPs) play a key role in transcriptional regulation and serve as invaluable tools for gene modification and genetic engineering. Development of efficient strategies for labeling metalloproteins such as ZFPs is essential for understanding and controlling biological processes. In this work, we engineered ZFPs containing cysteine-histidine (Cys2-His2) motifs by metabolic incorporation of the unnatural amino acid azidohomoalanine (AHA), followed by specific protein labeling via click chemistry. We show that cyclooctyne promoted [3 + 2] dipolar cycloaddition with azides, known as copper-free click chemistry, provides rapid and specific labeling of ZFPs at high yields as determined by mass spectrometry analysis. We observe that the DNA-binding activity of ZFPs labeled by conventional copper-mediated click chemistry was completely abolished, whereas ZFPs labeled by copper-free click chemistry retain their sequence-specific DNA-binding activity under native conditions, as determined by electrophoretic mobility shift assays, protein microarrays and kinetic binding assays based on Förster resonance energy transfer (FRET). Our work provides a general framework to label metalloproteins such as ZFPs by metabolic incorporation of unnatural amino acids followed by copper-free click chemistry. PMID:22871171

  15. Five-level Z-source diode-clamped inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, Poh Chiang; Blaabjerg, Frede

    2010-01-01

    This study proposes a five-level Z-source diode-clamped inverter designed with two intermediate Z-source networks connected between the dc input sources and rear-end inverter circuitry. By partially shorting the Z-source networks, new operating states not previously reported for two-level Z......-source inverter are introduced here for operating the proposed inverter with voltage buck–boost energy conversion ability and five-level phase voltage switching. These characteristic features are in fact always ensured at the inverter terminal output by simply adopting a properly designed carrier modulation...

  16. Unsupervised Learning (Clustering) of Odontocete Echolocation Clicks

    Science.gov (United States)

    2015-09-30

    develop methods for clustering of marine mammal echolocation clicks to learn about species assemblages where little or no prior knowledge exists about... Mexico or the Atlanic. 2 APPROACH Acoustic encounters with odontocetes are detected automatically and noise-corrected cepstral features...Estmation of Marine Mammals Using Passive Acoustic Monitoring (DCLDE). KL divergence maps were created for all known species, but the sperm whale

  17. Click chemistry based biomolecular conjugation monitoring using surface-enhanced Raman spectroscopy mapping

    DEFF Research Database (Denmark)

    Palla, Mirko; Kumar, Shiv; Li, Zengmin

    2016-01-01

    We describe here a novel surface-enhanced Raman spectroscopy (SERS) based technique for monitoring the conjugation of small molecules by the well-known click reaction between an alkyne and azido moiety on the partner molecules. The monitoring principle is based on the loss of the characteristic...... alkyne/azide Raman signal with triazole formation in the reaction as a function of time. Since these universal Raman reporter groups are specific for click reactions, this method may facilitate a broad range of applications for monitoring the conjugation efficiency of molecules in diverse areas...

  18. In situ click chemistry: from small molecule discovery to synthetic antibodies

    Science.gov (United States)

    Agnew, Heather D.; Lai, Bert; Lee, Su Seong; Lim, Jaehong; Nag, Arundhati; Pitram, Suresh; Rohde, Rosemary; Heath, James R.

    2013-01-01

    Advances in the fields of proteomics, molecular imaging, and therapeutics are closely linked to the availability of affinity reagents that selectively recognize their biological targets. Here we present a review of Iterative Peptide In Situ Click Chemistry (IPISC), a novel screening technology for designing peptide multiligands with high affinity and specificity. This technology builds upon in situ click chemistry, a kinetic target-guided synthesis approach where the protein target catalyzes the conjugation of two small molecules, typically through the azide–alkyne Huisgen cycloaddition. Integrating this methodology with solid phase peptide libraries enables the assembly of linear and branched peptide multiligands we refer to as Protein Catalyzed Capture Agents (PCC Agents). The resulting structures can be thought of as analogous to the antigen recognition site of antibodies and serve as antibody replacements in biochemical and cell-based applications. In this review, we discuss the recent progress in ligand design through IPISC and related approaches, focusing on the improvements in affinity and specificity as multiligands are assembled by target-catalyzed peptide conjugation. We compare the IPISC process to small molecule in situ click chemistry with particular emphasis on the advantages and technical challenges of constructing antibody-like PCC Agents. PMID:22836343

  19. Timing and context of dolphin clicks during and after mine simulator detection and marking in the open ocean

    Directory of Open Access Journals (Sweden)

    Sam H. Ridgway

    2018-02-01

    Full Text Available Two dolphins carrying cameras swam in the ocean as they searched for and marked mine simulators – buried, proud or moored. As the animals swam ahead of a boat they searched the ocean. Cameras on their harness recorded continuous sound and video. Once a target was detected, the dolphins received a marker to take to the simulator's location. During search and detection, dolphins made almost continuous trains of varying interval clicks. During the marking phase, shorter click trains were interrupted by periods of silence. As the dolphins marked simulators, they often produced victory squeals – pulse bursts that vary in duration, peak frequency and amplitude. Victory squeals were produced on 72% of marks. Sometimes after marking, or at other times during their long swims, the dolphins produced click packets. Packets typically consisted of two to 10 clicks with inter-click intervals of 7-117 ms followed by a silence of 223-983 ms. Click packets appeared unrelated with searching or marking. We suggest that the packets were used to improve signal to noise ratios for locating a boat or other distant object. Victory squeals produced when marking the targets suggest to us that the dolphins know when they have succeeded in this multipart task.

  20. Click polymerization for the synthesis of reduction-responsive polymeric prodrug

    Science.gov (United States)

    Zhang, Xiaojin; Wang, Hongquan; Dai, Yu

    2018-05-01

    Click polymerization is a powerful polymerization technique for the construction of new macromolecules with well-defined structures and multifaceted functionalities. Here, we synthesize reduction-responsive polymeric prodrug PEG- b-(PSS- g-MTX)- b-PEG containing disulfide bonds and pendant methotrexate (MTX) via two-step click polymerization followed by conjugating MTX to pendant hydroxyl. MTX content in polymeric prodrug is 13.5%. Polymeric prodrug is able to form polymeric micelles by self-assembly in aqueous solution. Polymeric micelles are spherical nanoparticles with tens of nanometers in size. Of note, polymeric micelles are reduction-responsive due to disulfide bonds in the backbone of PEG- b-(PSS- g-MTX)- b-PEG and could release pendant drugs in the presence of the reducing agents such as dl-dithiothreitol (DTT).

  1. Evaluation of Kentucky's "Click It or Ticket" 2008 campaign.

    Science.gov (United States)

    2008-07-01

    The objective of this report was to document the results of the "Click It or Ticket" 2008 campaign in Kentucky. The campaign involved a combination of earned media, paid media, and enforcement. : The evaluation of the campaign included documenting th...

  2. The combined effects of forward masking by noise and high click rate on monaural and binaural human auditory nerve and brainstem potentials.

    Science.gov (United States)

    Pratt, Hillel; Polyakov, Andrey; Bleich, Naomi; Mittelman, Naomi

    2004-07-01

    To study effects of forward masking and rapid stimulation on human monaurally- and binaurally-evoked brainstem potentials and suggest their relation to synaptic fatigue and recovery and to neuronal action potential refractoriness. Auditory brainstem evoked potentials (ABEPs) were recorded from 12 normally- and symmetrically hearing adults, in response to each click (50 dB nHL, condensation and rarefaction) in a train of nine, with an inter-click interval of 11 ms, that followed a white noise burst of 100 ms duration (50 dB nHL). Sequences of white noise and click train were repeated at a rate of 2.89 s(-1). The interval between noise and first click in the train was 2, 11, 22, 44, 66 or 88 ms in different runs. ABEPs were averaged (8000 repetitions) using a dwell time of 25 micros/address/channel. The binaural interaction components (BICs) of ABEPs were derived and the single, centrally located equivalent dipoles of ABEP waves I and V and of the BIC major wave were estimated. The latencies of dipoles I and V of ABEP, their inter-dipole interval and the dipole magnitude of component V were significantly affected by the interval between noise and clicks and by the serial position of the click in the train. The latency and dipole magnitude of the major BIC component were significantly affected by the interval between noise and clicks. Interval from noise and the click's serial position in the train interacted to affect dipole V latency, dipole V magnitude, BIC latencies and the V-I inter-dipole latency difference. Most of the effects were fully apparent by the first few clicks in the train, and the trend (increase or decrease) was affected by the interval between noise and clicks. The changes in latency and magnitude of ABEP and BIC components with advancing position in the click train and the interactions of click position in the train with the intervals from noise indicate an interaction of fatigue and recovery, compatible with synaptic depletion and replenishing

  3. Injectable dextran hydrogels fabricated by metal-free click chemistry for cartilage tissue engineering.

    Science.gov (United States)

    Wang, Xiaoyu; Li, Zihan; Shi, Ting; Zhao, Peng; An, Kangkang; Lin, Chao; Liu, Hongwei

    2017-04-01

    Injectable dextran-based hydrogels were prepared for the first time by bioorthogonal click chemistry for cartilage tissue engineering. Click-crosslinked injectable hydrogels based on cyto-compatible dextran (Mw=10kDa) were successfully fabricated under physiological conditions by metal-free alkyne-azide cycloaddition (click) reaction between azadibenzocyclooctyne-modified dextran (Dex-ADIBO) and azide-modified dextran (Dex-N 3 ). Gelation time of these dextran hydrogels could be regulated in the range of approximately 1.1 to 10.2min, depending on the polymer concentrations (5% or 10%) and ADIBO substitution degree (DS, 5 or 10) of Dex-ADIBO. Rheological analysis indicated that the dextran hydrogels were elastic and had storage moduli from 2.1 to 6.0kPa with increasing DS of ADIBO from 5 to 10. The in vitro tests revealed that the dextran hydrogel crosslinked from Dex-ADIBO DS 10 and Dex-N 3 DS 10 at a polymer concentration of 10% could support high viability of individual rabbit chondrocytes and the chondrocyte spheroids encapsulated in the hydrogel over 21days. Individual chondrocytes and chondrocyte spheroids in the hydrogel could produce cartilage matrices such as collagen and glycosaminoglycans. However, the chondrocyte spheroids produced a higher content of matrices than individual chondrocytes. This study indicates that metal-free click chemistry is effective to produce injectable dextran hydrogels for cartilage tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Click trains and the rate of information processing: does "speeding up" subjective time make other psychological processes run faster?

    Science.gov (United States)

    Jones, Luke A; Allely, Clare S; Wearden, John H

    2011-02-01

    A series of experiments demonstrated that a 5-s train of clicks that have been shown in previous studies to increase the subjective duration of tones they precede (in a manner consistent with "speeding up" timing processes) could also have an effect on information-processing rate. Experiments used studies of simple and choice reaction time (Experiment 1), or mental arithmetic (Experiment 2). In general, preceding trials by clicks made response times significantly shorter than those for trials without clicks, but white noise had no effects on response times. Experiments 3 and 4 investigated the effects of clicks on performance on memory tasks, using variants of two classic experiments of cognitive psychology: Sperling's (1960) iconic memory task and Loftus, Johnson, and Shimamura's (1985) iconic masking task. In both experiments participants were able to recall or recognize significantly more information from stimuli preceded by clicks than those preceded by silence.

  5. Click-evoked otoacoustic emissions in children and adolescents with gender identity disorder.

    Science.gov (United States)

    Burke, Sarah M; Menks, Willeke M; Cohen-Kettenis, Peggy T; Klink, Daniel T; Bakker, Julie

    2014-11-01

    Click-evoked otoacoustic emissions (CEOAEs) are echo-like sounds that are produced by the inner ear in response to click-stimuli. CEOAEs generally have a higher amplitude in women compared to men and neonates already show a similar sex difference in CEOAEs. Weaker responses in males are proposed to originate from elevated levels of testosterone during perinatal sexual differentiation. Therefore, CEOAEs may be used as a retrospective indicator of someone's perinatal androgen environment. Individuals diagnosed with Gender Identity Disorder (GID), according to DSM-IV-TR, are characterized by a strong identification with the other gender and discomfort about their natal sex. Although the etiology of GID is far from established, it is hypothesized that atypical levels of sex steroids during a critical period of sexual differentiation of the brain might play a role. In the present study, we compared CEOAEs in treatment-naïve children and adolescents with early-onset GID (24 natal boys, 23 natal girls) and control subjects (65 boys, 62 girls). We replicated the sex difference in CEOAE response amplitude in the control group. This sex difference, however, was not present in the GID groups. Boys with GID showed stronger, more female-typical CEOAEs whereas girls with GID did not differ in emission strength compared to control girls. Based on the assumption that CEOAE amplitude can be seen as an index of relative androgen exposure, our results provide some evidence for the idea that boys with GID may have been exposed to lower amounts of androgen during early development in comparison to control boys.

  6. Pure Play vs. Bricks-and-Clicks: Who Reaps the Benefits of Virtual Retailing?

    OpenAIRE

    Youlong Zhuang; Albert L. Lederer

    2006-01-01

    Pure play and bricks-and-clicks represent today’s two major retailing models. The current study answers four questions comparing the two models in terms of the e-commerce benefits achieved and information systems management practices used to achieve them. It applies a Web-based survey to compare 69 pure plays to 348 bricks-and-clicks retailers in terms of the market expansion, customer service, back-end efficiency, inventory management, and cost reduction benefits reaped, as well as in term...

  7. Click chemistry for [99mTc(CO)3] labeling of Lys3-bombesin

    International Nuclear Information System (INIS)

    Ferro-Flores, G.; Rivero, I.A.; Santos-Cuevas, C.L.; Sarmiento, J.I.; Arteaga de Murphy, C.; Ocampo-Garcia, B.E.; Garcia-Becerra, R.; Ordaz-Rosado, D.

    2010-01-01

    99m Tc-HYNIC labeled Lys 3 -bombesin has shown specific binding to gastrin-releasing peptide receptors (GRP-r) over-expressed in cancer cells. Click chemistry offers an innovative functionalization strategy for biomolecules such as bombesin. The aim of this research was to apply a click chemistry approach for [ 99m Tc(CO) 3 ] labeling of Lys 3 -bombesin and to compare the in vitro MCF7 breast cancer cell uptake and biodistribution profile in mice with that of 99m Tc-EDDA/HYNIC-Lys 3 -bombesin. The results suggest a higher lipophilicity for 99m Tc(CO) 3 -triazole-Lys 3 -bombesin which explains its higher in vivo hepatobiliary elimination. Pancreas-to-blood ratio for 99m Tc(CO) 3 -triazole-Lys 3 -bombesin was 4.46 at 3 h and both bombesin radiopharmaceuticals showed specific recognition for GRP receptors in MCF7 cancer cells. Click chemistry is a reliable approach for [ 99m Tc(CO) 3 ] labeling of Lys 3 -bombesin.

  8. Click chemistry approach to functionalize two-dimensional macromolecules of graphene oxide nanosheets

    Institute of Scientific and Technical Information of China (English)

    Liang Kou; Hongkun He; Chao Gao

    2010-01-01

    A facile 'click chemistry' approach to functionalize 2D macromolecules of graphene oxide nanosheets with poly(ethylene glycol) of different molecular weights,polystyrene,palmitic acid and various amino acids was presented.FTIR,TGA,Raman spectroscopy,XPS,XRD,TEM,AFM and SEM were utilized to characterize the products.High degree of functionalization was achieved on the flat surfaces of graphene oxide,affording polymer-grafted 2D brushes and amino acids-immobilized nanosheets,which show improved solubility in organic solvents.The click chemistry strategy reported herein provides a facile and general method for functionalization of graphene oxide with macromolecules and desired biomolecules.

  9. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hansen, Thomas S.; Larsen, Niels Bent

    2011-01-01

    Microwave (MW) irradiation has been used to accelerate the functionalization of an azide functional poly(3,4-ethylenedioxythiophene) film by click chemistry. The absorption of MW energy by the conductive polymer has been exploited for localized activation of the reaction on the polymer surface...

  10. Methoxypropylamino β-cyclodextrin clicked AC regioisomer for enantioseparations in capillary electrophoresis

    International Nuclear Information System (INIS)

    Zhou, Jie; Wang, Yiying; Liu, Yun; Tang, Jian; Tang, Weihua

    2015-01-01

    Highlights: In this paper, we demonstrate: • The click synthesis of a AC regioisomer cationic cyclodextrin (CD) as chiral selector. • The good enantioselectivities (chiral resolution over 5) for acidic racemates. • The strong chiral recognition of new CD by NMR study. • Baseline enantioseparation of some acidic racemates at CD of 0.5 mM. - Abstract: In this work, a novel methoxypropylamino β-cyclodextrin (β-CD) clicked AC regioisomer, 6 A -4-hydroxyethyl-1,2,3-triazolyl-6 C -3-methoxypropylamino β-cyclodextrin (HETz-MPrAMCD), was synthesized via nucleophilic addition and click chemistry. The chiral separation ability of this AC regioisomer cationic CD was evaluated toward 7 ampholytic and 13 acidic racemates by capillary electrophoresis. Dependence of enantioselectivity and resolution on buffer pH (5.5–8.0) and chiral selector concentration (0.5–7.5 mM) was investigated. Enantioselectivities (α ≥ 1.05) could be achieved for most analytes under optimal conditions except dansyl-DL-noreleucine and dansyl-DL-serine. The highest resolutions for 2-chloromandelic acid p-hydroxymandelic acid were 15.6 and 9.7 respectively. The inclusion complexation between HETz-MPrAMCD and each 3-phenyllactic acid enantiomer was also revealed with nuclear magnetic resonance study

  11. Methoxypropylamino β-cyclodextrin clicked AC regioisomer for enantioseparations in capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jie; Wang, Yiying; Liu, Yun; Tang, Jian; Tang, Weihua, E-mail: whtang@mail.njust.edu.cn

    2015-04-08

    Highlights: In this paper, we demonstrate: • The click synthesis of a AC regioisomer cationic cyclodextrin (CD) as chiral selector. • The good enantioselectivities (chiral resolution over 5) for acidic racemates. • The strong chiral recognition of new CD by NMR study. • Baseline enantioseparation of some acidic racemates at CD of 0.5 mM. - Abstract: In this work, a novel methoxypropylamino β-cyclodextrin (β-CD) clicked AC regioisomer, 6{sup A}-4-hydroxyethyl-1,2,3-triazolyl-6{sup C}-3-methoxypropylamino β-cyclodextrin (HETz-MPrAMCD), was synthesized via nucleophilic addition and click chemistry. The chiral separation ability of this AC regioisomer cationic CD was evaluated toward 7 ampholytic and 13 acidic racemates by capillary electrophoresis. Dependence of enantioselectivity and resolution on buffer pH (5.5–8.0) and chiral selector concentration (0.5–7.5 mM) was investigated. Enantioselectivities (α ≥ 1.05) could be achieved for most analytes under optimal conditions except dansyl-DL-noreleucine and dansyl-DL-serine. The highest resolutions for 2-chloromandelic acid p-hydroxymandelic acid were 15.6 and 9.7 respectively. The inclusion complexation between HETz-MPrAMCD and each 3-phenyllactic acid enantiomer was also revealed with nuclear magnetic resonance study.

  12. Predicting clicks of PubMed articles.

    Science.gov (United States)

    Mao, Yuqing; Lu, Zhiyong

    2013-01-01

    Predicting the popularity or access usage of an article has the potential to improve the quality of PubMed searches. We can model the click trend of each article as its access changes over time by mining the PubMed query logs, which contain the previous access history for all articles. In this article, we examine the access patterns produced by PubMed users in two years (July 2009 to July 2011). We explore the time series of accesses for each article in the query logs, model the trends with regression approaches, and subsequently use the models for prediction. We show that the click trends of PubMed articles are best fitted with a log-normal regression model. This model allows the number of accesses an article receives and the time since it first becomes available in PubMed to be related via quadratic and logistic functions, with the model parameters to be estimated via maximum likelihood. Our experiments predicting the number of accesses for an article based on its past usage demonstrate that the mean absolute error and mean absolute percentage error of our model are 4.0% and 8.1% lower than the power-law regression model, respectively. The log-normal distribution is also shown to perform significantly better than a previous prediction method based on a human memory theory in cognitive science. This work warrants further investigation on the utility of such a log-normal regression approach towards improving information access in PubMed.

  13. N-PEG´ylation of chitosan via "click chemistry" reactions

    Czech Academy of Sciences Publication Activity Database

    Kulbokaite, R.; Ciuta, G.; Netopilík, Miloš; Makuška, R.

    2009-01-01

    Roč. 69, č. 10 (2009), s. 771-778 ISSN 1381-5148 R&D Projects: GA ČR GA203/07/0659 Institutional research plan: CEZ:AV0Z40500505 Keywords : chitosan * poly(ethylene glycol) * click chemistry Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.461, year: 2009

  14. Five-Level Z-Source Neutral Point-Clamped Inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    This paper proposes a five-level Z-source neutralpoint- clamped (NPC) inverter with two Z-source networks functioning as intermediate energy storages coupled between dc sources and NPC inverter circuitry. Analyzing the operational principles of Z-source network with partial dclink shoot......-through scheme reveals the hidden theories in the five-level Z-source NPC inverter unlike the operational principle appeared in the general two-level Z-source inverter, so that the five-level Z-source NPC inverter can be designed with the modulation of carrier-based phase disposition (PD) or alternative phase...

  15. Nanofabrication Yields. Hybridization and Click-Fixation of Polycyclic DNA Nanoassemblies

    KAUST Repository

    Lundberg, Erik P.; Plesa, Calin; Wilhelmsson, L. Marcus; Lincoln, Per; Brown, Tom; Nordén, Bengt

    2011-01-01

    introduced site-specific click chemistry for making and purifying robust building blocks for future modular constructs of larger assemblies. Although the present yield of this robust module was only about 10%, it demonstrates a first step toward a general

  16. Evaluation of 4-[18F]fluoro-1-butyne as a radiolabeled synthon for click chemistry with azido compounds

    International Nuclear Information System (INIS)

    Kim, Dong Hyun; Choe, Yearn Seong; Kim, Byung-Tae

    2010-01-01

    Click chemistry is a useful approach for the preparation of novel radiopharmaceuticals. In this study, we evaluated 4-[ 18 F]fluoro-1-butyne as a radiolabeled synthon for click chemistry with azido compounds. Our results showed that nucleophilic substitution of 4-tosyloxy-1-butyne with K[ 18 F]F produces vinyl acetylene as well as 4-[ 18 F]fluoro-1-butyne, while the same reaction using 5-tosyloxy-1-pentyne gives exclusively 5-[ 18 F]fluoro-1-pentyne. Thus, ω-[ 18 F]fluoro-1-alkynes with chain lengths longer than four carbons may be better radiolabeled synthons for use in click chemistry.

  17. On-Surface Synthesis by Click Chemistry Investigated by STM and XPS

    DEFF Research Database (Denmark)

    Vadapoo, Sundar Raja

    2014-01-01

    Molecular synthesis is essential in the bottom-up approach of achieving highly stable nanostructures. On-surface synthesis is highly interesting from the basic science of view to improve the understanding of molecular behavior adsorbed on metal surfaces, and has potential applications such as mol......Molecular synthesis is essential in the bottom-up approach of achieving highly stable nanostructures. On-surface synthesis is highly interesting from the basic science of view to improve the understanding of molecular behavior adsorbed on metal surfaces, and has potential applications...... such as molecular electronics and surface functionalization. In this thesis, a well-defined click chemistry approach is followed, with the study of azide-alkyne cycloaddition on Cu(111) surface in UHV environment. A successful achievement of the click reaction product via on-surface synthesis has been shown, which...

  18. Pyrrolidine constrained bipyridyl-dansyl click fluoroionophore as selective Al(3+)sensor.

    Science.gov (United States)

    Maity, Debabrata; Govindaraju, T

    2010-07-07

    A pyrrolidine constrained bipyridyl-dansyl (ionophore-fluorophore) conjugate with triazole linker was synthesised through click chemistry. The fluoroionophore serves as a selective ratiometric and colorimetric chemosensor for Al(3+) based on internal charge transfer (ICT).

  19. "Click" saccharide/beta-lactam hybrids for lectin inhibition.

    Science.gov (United States)

    Palomo, Claudio; Aizpurua, Jesus M; Balentová, Eva; Azcune, Itxaso; Santos, J Ignacio; Jiménez-Barbero, Jesús; Cañada, Javier; Miranda, José Ignacio

    2008-06-05

    Hybrid glycopeptide beta-lactam mimetics designed to bind lectins or carbohydrate recognition domains in selectins have been prepared according to a "shape-modulating linker" design. This approach was implemented using the azide-alkyne "click" cycloaddition reaction, and as shown by NMR/MD experiments, binding of the resulting mimetics to Ulex Europaeus Lectin-1 (UEL-1) occurred after a "bent-to-extended" conformational change around a partially rotatable triazolylmethylene moiety.

  20. Protein addressing on patterned microchip by coupling chitosan electrodeposition and 'electro-click' chemistry.

    Science.gov (United States)

    Shi, Xiao-Wen; Qiu, Ling; Nie, Zhen; Xiao, Ling; Payne, Gregory F; Du, Yumin

    2013-12-01

    Many applications in proteomics and lab-on-chip analysis require methods that guide proteins to assemble at surfaces with high spatial and temporal control. Electrical inputs are particularly convenient to control, and there has been considerable effort to discover simple and generic mechanisms that allow electrical inputs to trigger protein assembly on-demand. Here, we report the electroaddressing of a protein to a patterned surface by coupling two generic electroaddressing mechanisms. First, we electrodeposit the stimuli-responsive film-forming aminopolysaccharide chitosan to form a hydrogel matrix at the electrode surface. After deposition, the matrix is chemically functionalized with alkyne groups. Second, we ''electro-click' an azide-tagged protein to the functionalized matrix using electrical signals to trigger conjugation by Huisgen 1,3-dipolar cycloadditions. Specifically, a cathodic potential is applied to the matrix-coated electrode to reduce Cu(II) to Cu(I) which is required for the click reaction. Using fluorescently-labeled bovine serum albumin as our model, we demonstrate that protein conjugation can be controlled spatially and temporally. We anticipate that the coupling of polysaccharide electrodeposition and electro-click chemistry will provide a simple and generic approach to electroaddress proteins within compatible hydrogel matrices.

  1. Versatility of Alkyne-Modified Poly(Glycidyl Methacrylate) Layers for Click Reactions

    International Nuclear Information System (INIS)

    Soto-Cantu, Erick; Lokitz, Bradley S.; Hinestrosa Salazar, Juan Pablo; Deodhar, Chaitra; Messman, Jamie M.; Ankner, John Francis; Kilbey, S. Michael II

    2011-01-01

    Functional soft interfaces are of interest for a variety of technologies. We describe three methods for preparing substrates with alkyne groups, which show versatility for 'click' chemistry reactions. Two of the methods have the same root: formation of thin, covalently attached, reactive interfacial layers of poly(glycidyl methacrylate) (PGMA) via spin coating onto silicon wafers followed by reactive modification with either propargylamine or 5-hexynoic acid. The amine or the carboxylic acid moieties react with the epoxy groups of PGMA, creating interfacial polymer layers decorated with alkyne groups. The third method consists of using copolymers comprising glycidyl methacrylate and propargyl methacrylate (pGP). The pGP copolymers are spin coated and covalently attached on silicon wafers. For each method, we investigate the factors that control film thickness and content of alkyne groups using ellipsometry, and study the nanophase structure of the films using neutron reflectometry. Azide-terminated polymers of methacrylic acid and 2-vinyl-4,4-dimethylazlactone synthesized via reversible addition-fragmentation chain transfer polymerization were attached to the alkyne-modified substrates using 'click' chemistry, and grafting densities in the range of 0.007-0.95 chains nm -2 were attained. The maximum density of alkyne groups attained by functionalization of PGMA with propargylamine or 5-hexynoic acid was approximately 2 alkynes nm -3 . The alkyne content obtained by the three decorating approaches was sufficiently high that it was not the limiting factor for the click reaction of azide-capped polymers.

  2. Optimized Cost per Click in Taobao Display Advertising

    OpenAIRE

    Zhu, Han; Jin, Junqi; Tan, Chang; Pan, Fei; Zeng, Yifan; Li, Han; Gai, Kun

    2017-01-01

    Taobao, as the largest online retail platform in the world, provides billions of online display advertising impressions for millions of advertisers every day. For commercial purposes, the advertisers bid for specific spots and target crowds to compete for business traffic. The platform chooses the most suitable ads to display in tens of milliseconds. Common pricing methods include cost per mille (CPM) and cost per click (CPC). Traditional advertising systems target certain traits of users and...

  3. Assessing the Mitochondrial Membrane Potential in Cells and In Vivo using Targeted Click Chemistry and Mass Spectrometry.

    Science.gov (United States)

    Logan, Angela; Pell, Victoria R; Shaffer, Karl J; Evans, Cameron; Stanley, Nathan J; Robb, Ellen L; Prime, Tracy A; Chouchani, Edward T; Cochemé, Helena M; Fearnley, Ian M; Vidoni, Sara; James, Andrew M; Porteous, Carolyn M; Partridge, Linda; Krieg, Thomas; Smith, Robin A J; Murphy, Michael P

    2016-02-09

    The mitochondrial membrane potential (Δψm) is a major determinant and indicator of cell fate, but it is not possible to assess small changes in Δψm within cells or in vivo. To overcome this, we developed an approach that utilizes two mitochondria-targeted probes each containing a triphenylphosphonium (TPP) lipophilic cation that drives their accumulation in response to Δψm and the plasma membrane potential (Δψp). One probe contains an azido moiety and the other a cyclooctyne, which react together in a concentration-dependent manner by "click" chemistry to form MitoClick. As the mitochondrial accumulation of both probes depends exponentially on Δψm and Δψp, the rate of MitoClick formation is exquisitely sensitive to small changes in these potentials. MitoClick accumulation can then be quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This approach enables assessment of subtle changes in membrane potentials within cells and in the mouse heart in vivo. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  4. The inverse electron demand Diels-Alder click reaction in radiochemistry.

    Science.gov (United States)

    Reiner, Thomas; Zeglis, Brian M

    2014-04-01

    The inverse electron-demand Diels-Alder (IEDDA) cycloaddition between 1,2,4,5-tetrazines and strained alkene dienophiles is an emergent variety of catalyst-free 'click' chemistry that has the potential to have a transformational impact on the synthesis and development of radiopharmaceuticals. The ligation is selective, rapid, high-yielding, clean, and bioorthogonal and, since its advent in 2008, has been employed in a wide variety of chemical settings. In radiochemistry, the reaction has proven particularly useful with (18)  F and has already been utilized to create a number of (18)  F-labeled agents, including the PARP1-targeting small molecule (18)  F-AZD2281, the αv β3 integrin-targeting peptide (18)  F-RGD, and the GLP-1-targeting peptide (18)  F-exendin. The inherent flexibility of the ligation has also been applied to the construction of radiometal-based probes, specifically the development of a modular strategy for the synthesis of radioimmunoconjugates that effectively eliminates variability in the construction of these agents. Further, the exceptional speed and biorthogonality of the reaction have made it especially promising in the realm of in vivo pretargeted imaging and therapy, and pretargeted imaging strategies based on the isotopes (111) In, (18)  F, and (64) Cu have already proven capable of producing images with high tumor contrast and low levels of uptake in background, nontarget organs. Ultimately, the characteristics of inverse electron-demand Diels-Alder click chemistry make it almost uniquely well-suited for radiochemistry, and although the field is young, this ligation has the potential to make a tremendous impact on the synthesis, development, and study of novel radiopharmaceuticals. Copyright © 2013 John Wiley & Sons, Ltd.

  5. Solvent-resistant nanofiltration for product purification and catalyst recovery in click chemistry reactions.

    Science.gov (United States)

    Cano-Odena, Angels; Vandezande, Pieter; Fournier, David; Van Camp, Wim; Du Prez, Filip E; Vankelecom, Ivo F J

    2010-01-18

    The quickly developing field of "click" chemistry would undoubtedly benefit from the availability of an easy and efficient technology for product purification to reduce the potential health risks associated with the presence of copper in the final product. Therefore, solvent-resistant nanofiltration (SRNF) membranes have been developed to selectively separate "clicked" polymers from the copper catalyst and solvent. By using these solvent-stable cross-linked polyimide membranes in diafiltration, up to 98 % of the initially present copper could be removed through the membrane together with the DMF solvent, the polymer product being almost completely retained. This paper also presents the first SRNF application in which the catalyst permeates through the membrane and the reaction product is retained.

  6. Grafting of Polycaprolactone on Oxidized Nanocelluloses by Click Chemistry

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2013-03-01

    Full Text Available The main objective of this work is the grafting of polycaprolactone diol (PCL on the surface of oxidized nanocelluloses (ONC in order to enhance the compatibility between the hydrophilic cellulose nanofibres and the hydrophobic polymer matrix. This grafting was successfully realized with a new strategy known as click chemistry. In this context, the oxidized nanocelluloses bearing alkyl groups (ONC-PR were prepared by reacting amino groups of propargylamine (PR with carboxyl groups of ONC. In parallel, PCL was converted into azido-polycaprolactone (PCL-N3 in two steps: (i tosylation of polycaprolactone (PCL-OTs and (ii conversion of PCL-OTs into PCL-N3 by nucleophilic displacement using sodium azide. Finally, ONC-PR was reacted with PCL-N3 in heterogeneous conditions through click chemistry in order to prepare polycaprolactone grafted oxidized nanocellulose (ONC-g-PCL, which could be suitable for improving the interfacial adhesion in the composite materials. The grafted samples were characterized by transmission electron microscopy and by Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS and Carbon-13 nuclear magnetic resonance spectroscopy (13C-NMR spectroscopic techniques.

  7. Grafting of Polycaprolactone on Oxidized Nanocelluloses by Click Chemistry

    Science.gov (United States)

    Benkaddour, Abdelhaq; Jradi, Khalil; Robert, Sylvain; Daneault, Claude

    2013-01-01

    The main objective of this work is the grafting of polycaprolactone diol (PCL) on the surface of oxidized nanocelluloses (ONC) in order to enhance the compatibility between the hydrophilic cellulose nanofibres and the hydrophobic polymer matrix. This grafting was successfully realized with a new strategy known as click chemistry. In this context, the oxidized nanocelluloses bearing alkyl groups (ONC-PR) were prepared by reacting amino groups of propargylamine (PR) with carboxyl groups of ONC. In parallel, PCL was converted into azido-polycaprolactone (PCL-N3) in two steps: (i) tosylation of polycaprolactone (PCL-OTs) and (ii) conversion of PCL-OTs into PCL-N3 by nucleophilic displacement using sodium azide. Finally, ONC-PR was reacted with PCL-N3 in heterogeneous conditions through click chemistry in order to prepare polycaprolactone grafted oxidized nanocellulose (ONC-g-PCL), which could be suitable for improving the interfacial adhesion in the composite materials. The grafted samples were characterized by transmission electron microscopy and by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Carbon-13 nuclear magnetic resonance spectroscopy (13C-NMR) spectroscopic techniques. PMID:28348327

  8. EXCTRA - EXploiting the Click-TRAil : Assessing the benefits of Learning Analytics

    NARCIS (Netherlands)

    Conijn, Rianne; Snijders, Chris; Matzat, Uwe; Kleingeld, Ad; Nij Bijvank, Wouter

    2016-01-01

    Currently, Learning Management Systems (LMS) are being used in the majority of educational institutions to provide learning materials online. As a by-product of these systems—every click is recorded—one gets a rich amount of data about students’ online behaviour. Recently many researchers have

  9. Navigation To and From a Page: Which Links Get Clicked From Where

    Science.gov (United States)

    Use Google Analytics navigation summary data to find out what page users most frequently click your Contact Us link from (Previous Page Path), or which links on your homepage are popular or unpopular (Next Page Path).

  10. Au-Cu core-shell nanocube-catalyzed click reactions for efficient synthesis of diverse triazoles.

    Science.gov (United States)

    Madasu, Mahesh; Hsia, Chi-Fu; Huang, Michael H

    2017-06-01

    Au-Cu core-shell nanocubes and octahedra synthesized in aqueous solution were employed to catalyze a 1,3-dipolar cycloaddition reaction between phenylacetylene and benzyl azide in water at 50 °C for 3 h. Interestingly, the nanocubes were far more efficient in catalyzing this reaction, giving 91% yield of a regioselective 1,4-triazole product, while octahedra only recorded 46% yield. The Au-Cu nanocubes were subsequently employed to catalyze the click reaction between benzyl azide and a broad range of aromatic and aliphatic alkynes. The product yields ranged from 78 to 99%. Clearly the Au-Cu cubes exposing {100} surfaces are an excellent and green catalyst for click reactions.

  11. A Click Chemistry Approach towards Flavin-Cyclodextrin Conjugates-Bioinspired Sulfoxidation Catalysts

    Czech Academy of Sciences Publication Activity Database

    Tomanová, P.; Šturala, J.; Buděšínský, Miloš; Cibulka, R.

    2015-01-01

    Roč. 20, č. 11 (2015), s. 19837-19848 ISSN 1420-3049 Institutional support: RVO:61388963 Keywords : click chemistry * cyclodextrin * flavin * monooxygenase * oxidation * sulfoxides * green chemistry Subject RIV: CC - Organic Chemistry Impact factor: 2.465, year: 2015 http://www.mdpi.com/1420-3049/20/11/19667/htm

  12. Selling You and Your Clicks: Examining the Audience Commodification of Google

    Directory of Open Access Journals (Sweden)

    Hyunjin Kang

    2011-06-01

    Full Text Available Using a political economy perspective, this paper argues that Google’s surplus value from advertising results from its extensive and transformative commodification of users. The unique features of Google as an advertising venue intensify the commodification of its users as compared to traditional media in several ways. First, the simplified valorization process of Google’s advertising methods enables Google to earn significantly more surplus value than those of traditional media. Also, Google’s personalized advertising strategies, its precise measurement of advertising costs based on users’ behaviors represented as “the number of clicks,” and the unclear distinction between advertisements and serviced content commodify its users’ online activities. Lastly, this essay asserts that Google commodifies the aggregated consciousnesses of its users because it sells keywords for advertisers to attach advertisements to search-data output, which are priced in accordance with their popularity. This “click-through” form of behavioral commodification has significant implications for the future of media.

  13. The effects of temporo mandibular joint disorder with clicking symptom on children mastication performance in Deutero Malay race children aged 12-15 years

    Directory of Open Access Journals (Sweden)

    Henri Hartman

    2014-11-01

    Full Text Available Temporo Mandibular Joint Disorder (TMD could be caused by forward head posture. Articular sound/TMJ clicking is the most often sign and symptom for TMD that could happen in human being. The presence of TMD such as TMJ clicking would cause an imbalance masticatory system. The purpose of this research is to investigate TMJ clicking effects to masticatory performance. This research was cross-sectional study with a type of epidemiology survey. Subject were children aged 12-15 years old Deutero-Malay sub-races Live in Bandung and was taken using multi-stage random sampling technique. Subject; consisted of 24 children as control group and 28 children as TMJ clicking group. Both group were then checked for masticatory performance using multiple sieve method and 20x chewing of artificial test food. Mastication performance value represented by median particle size (MPS particle distribution (b for each group. MPS from TMJ clicking group (3.0571,SD=0.9990 showed higher value than control group (2.28958,SD=0.66838. Statistic analysis with t-test showed that there’s a significant result in both of group (pvalue=0,0024, α = 0,05. Conclussion, temporo mandibular joint clicking subject has lower masticatory performance.

  14. Functionalization of PEDOT by Click Chemistry and ATRP

    DEFF Research Database (Denmark)

    Hoffmann, Christian; Daugaard, Anders Egede

    Poly(3,4‐ethylenedioxythiophene) (PEDOT) is a conductive polymer which has received increasing attention and many developments have been investigated. PEDOT has been applied in many different areas such as biosensors or polymer solar cells. This work presents a modification of PEDOT films through...... Click Chemistry with alkynes followed by activator regenerated by electron transfer (ARGET) atom transfer radical polymerization (ATRP) to develop PEDOT films with anti‐fouling properties through application of a model system based on a crosslinked surface of polystyrene PS‐N3....

  15. Multi-channel services for click and mortars : Development of a design method

    NARCIS (Netherlands)

    Simons, L.P.A.

    2006-01-01

    The rise of Internet commerce led to multiple predictions of disintermediation and the decline of physical shopping. However, a "click and mortar" approach, which combines online, offline and telephone contact, has added value for customers and for supplier profitability, as recent research

  16. Frequency of temporomandibular joint dysfunction with clicking symptom due to primary molar premature loss in children aged 6-12 years old

    Directory of Open Access Journals (Sweden)

    Riana Hestu Laksitowati

    2009-03-01

    Full Text Available Temporomandibular joint dysfunction with clicking symptom is sound “click” when open and close the mouth. The purpose of this study was to obtain the description of the frequency of temporomandibular joint dysfunction with clicking symptom caused by premature loss of primary molar teeth in children aged 6-12 years old at SDIT Imam Bukhari. The study was a descriptive survey, 136 students as samples were taken by purposive sampling technique. Premature loss of primary molar teeth examined by checking up the first and second primary molars upper and lower jaw using the hand mirror and explorer. Temporomandibular joint dysfunction examined by palpation and using a stethoscope. The result of this study showed that from 136 students having premature loss there are 49 students (36,03% had temporomandibular joint dysfunction with clicking symptom. The conclusion of this study indicates that more than one-fourth students at SDIT Imam Bukhari with premature loss of primary molar teeth had temporomandibular joint dysfunction with clicking symptom.

  17. Click chemistry for [{sup 99m}Tc(CO){sub 3}] labeling of Lys{sup 3}-bombesin

    Energy Technology Data Exchange (ETDEWEB)

    Ferro-Flores, G., E-mail: ferro_flores@yahoo.com.m [Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, C.P. 52750 (Mexico); Rivero, I.A. [Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, C.P. 52750 (Mexico); Instituto Tecnologico de Tijuana, Baja California (Mexico); Santos-Cuevas, C.L. [Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, C.P. 52750 (Mexico); Universidad Autonoma del Estado de Mexico (Mexico); Sarmiento, J.I. [Instituto Tecnologico de Tijuana, Baja California (Mexico); Arteaga de Murphy, C. [Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran (Mexico); Ocampo-Garcia, B.E. [Departamento de Materiales Radiactivos, Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca S/N, La Marquesa, Ocoyoacac, Estado de Mexico, C.P. 52750 (Mexico); Garcia-Becerra, R.; Ordaz-Rosado, D. [Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran (Mexico)

    2010-12-15

    {sup 99m}Tc-HYNIC labeled Lys{sup 3}-bombesin has shown specific binding to gastrin-releasing peptide receptors (GRP-r) over-expressed in cancer cells. Click chemistry offers an innovative functionalization strategy for biomolecules such as bombesin. The aim of this research was to apply a click chemistry approach for [{sup 99m}Tc(CO){sub 3}] labeling of Lys{sup 3}-bombesin and to compare the in vitro MCF7 breast cancer cell uptake and biodistribution profile in mice with that of {sup 99m}Tc-EDDA/HYNIC-Lys{sup 3}-bombesin. The results suggest a higher lipophilicity for {sup 99m}Tc(CO){sub 3}-triazole-Lys{sup 3}-bombesin which explains its higher in vivo hepatobiliary elimination. Pancreas-to-blood ratio for {sup 99m}Tc(CO){sub 3}-triazole-Lys{sup 3}-bombesin was 4.46 at 3 h and both bombesin radiopharmaceuticals showed specific recognition for GRP receptors in MCF7 cancer cells. Click chemistry is a reliable approach for [{sup 99m}Tc(CO){sub 3}] labeling of Lys{sup 3}-bombesin.

  18. The 2007 click it or ticket high-visibility seat belt mobilization : traffic tech.

    Science.gov (United States)

    2010-09-01

    In May 2007 the National Highway Traffic Safety Administration : sponsored the fifth national Click It or Ticket (CIOT) : high-visibility seat belt enforcement mobilization, which followed : the CIOT program model of earned and paid media : publicizi...

  19. Understanding Mircrobial Sensing in Inflammatory Bowel Disease Using Click Chemistry

    Science.gov (United States)

    2016-10-01

    chemistry , microbiology and worked with the second fellow from von Andrian lab on the immunology and microscopy. Teaching has come from several...to follow essentially any bacteria using fluorescent techniques into the host or other environments. This chemistry is also a potential method for...AWARD NUMBER: W81XWH-15-1-0367 TITLE: Understanding Microbial Sensing in Inflammatory Bowel Disease Using Click Chemistry PRINCIPAL

  20. Synthesis and Catalytic Applications of Ruthenium(0) Nanoparticles in Click Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avvaru Praveen; Baek, Minwook; Sridhar, Chirumarry; Kumar, Begari Prem; Lee, Yongill [Changwon National Univ., Changwon (Korea, Republic of)

    2014-04-15

    Here we report a facile synthesis of ruthenium (Ru) Nanoparticles (NPs) by chemical co-precipitation method. The calcination of ruthenium hydroxide samples at 500 .deg. C under hydrogen atmosphere lead to the formation of Ru{sup 0} NPs. The size and aggregation of Ru NPs depends on the pH of the medium, and type of surfactant and its concentration. The X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope image (TEM) analyses of particles indicated the formation of Ru{sup 0} NPs, and have 10 to 20 nm sizes. As-synthesized Ru{sup 0} NPs are characterized and investigated their catalytic ability in click chemistry (azide-alkyne cycloaddition reactions), showing good results in terms of reactivity. Interestingly, small structural differences in triazines influence the catalytic activity of Ru{sup 0} nanocatalysts. Click chemistry has recently emerged to become one of the most powerful tools in drug discovery, chemical biology, proteomics, medical sciences and nanotechnology/nanomedicine. In addition, preliminary tests of recycling showed good results with neither loss of activity or significant precipitation.

  1. Conjugating folate on superparamagnetic Fe3O4@Au nanoparticles using click chemistry

    International Nuclear Information System (INIS)

    Shen, Xiaofang; Ge, Zhaoqiang; Pang, Yuehong

    2015-01-01

    Gold-coated magnetic core@shell nanoparticles, which exhibit magneto-optical properties, not only enhance the chemical stability of core and biocompatibility of surface, but also provide a combination of multimodal imaging and therapeutics. The conjugation of these tiny nanoparticles with specific biomolecules allows researchers to target the desired location. In this paper, superparamagnetic Fe 3 O 4 @Au nanoparticles were synthesized and functionalized with the azide group on the surface by formation of self-assembled monolayers. Folate (FA) molecules, non-immunogenic target ligands for cancer cells, are conjugated with alkyne and then immobilized on the azide-terminated Fe 3 O 4 @Au nanoparticles through copper(I)-catalyzed azide-alkyne cycloaddition (click reaction). Myelogenous leukemia K562 cells were used as a folate receptor (FR) model, which can be targeted and extracted by magnetic field after interaction with the Fe 3 O 4 @Au–FA nanoparticles. - Graphical abstract: Self-assembled azide-terminated group on superparamagnetic Fe 3 O 4 @Au nanoparticles followed by click reaction with alkyne-functionalized folate, allowing the nanoparticles target folate receptor of cancer cells. - Highlights: • Azidoundecanethiol was coated on the superparamagnetic Fe 3 O 4 @Au nanoparticles by forming self-assembled monolayers. • Alkyne-terminated folate was synthesized from a reaction between the amine and the carboxylic acid. • Conjugation of Fe 3 O 4 @Au nanoparticles with folate was made by copper-catalyzed azide-alkyne cycloaddition click chemistry

  2. Pressurized transient otoacoustic emissions measured using click and chirp stimuli.

    Science.gov (United States)

    Keefe, Douglas H; Patrick Feeney, M; Hunter, Lisa L; Fitzpatrick, Denis F; Sanford, Chris A

    2018-01-01

    Transient-evoked otoacoustic emission (TEOAE) responses were measured in normal-hearing adult ears over frequencies from 0.7 to 8 kHz, and analyzed with reflectance/admittance data to measure absorbed sound power and the tympanometric peak pressure (TPP). The mean TPP was close to ambient. TEOAEs were measured in the ear canal at ambient pressure, TPP, and fixed air pressures from 150 to -200 daPa. Both click and chirp stimuli were used to elicit TEOAEs, in which the incident sound pressure level was constant across frequency. TEOAE levels were similar at ambient and TPP, and for frequencies from 0.7 to 2.8 kHz decreased with increasing positive and negative pressures. At 4-8 kHz, TEOAE levels were larger at positive pressures. This asymmetry is possibly related to changes in mechanical transmission through the ossicular chain. The mean TEOAE group delay did not change with pressure, although small changes were observed in the mean instantaneous frequency and group spread. Chirp TEOAEs measured in an adult ear with Eustachian tube dysfunction and TPP of -165 daPa were more robust at TPP than at ambient. Overall, results demonstrate the feasibility and clinical potential of measuring TEOAEs at fixed pressures in the ear canal, which provide additional information relative to TEOAEs measured at ambient pressure.

  3. 27-Level DC–AC inverter with single energy source

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2012-01-01

    Highlights: ► This paper reports a novel 27-level DC–AC inverter using only single renewable energy source. ► The efficiency of the inverter is very high. The output waveform is almost sinusoidal. ► The cost is low as the number of power switches required is only 12. - Abstract: A novel design of multilevel DC–AC inverter using only single renewable energy source is presented in this paper. The proposed approach enables multilevel output to be realised by a few cascaded H-bridges and a single energy source. As an illustration, a 27-level inverter has been implemented based on three cascaded H-bridges with a single energy source and two capacitors. Using the proposed novel switching strategy, 27 levels can be realized and the two virtual energy sources can be well regulated. Experimental results are included to demonstrate the effectiveness of the proposed inverter.

  4. Irreversible bonding of polyimide and polydimethylsiloxane (PDMS) based on a thiol-epoxy click reaction

    International Nuclear Information System (INIS)

    Hoang, Michelle V; Chung, Hyun-Joong; Elias, Anastasia L

    2016-01-01

    Polyimide is one of the most popular substrate materials for the microfabrication of flexible electronics, while polydimethylsiloxane (PDMS) is the most widely used stretchable substrate/encapsulant material. These two polymers are essential in fabricating devices for microfluidics, bioelectronics, and the internet of things; bonding these materials together is a crucial challenge. In this work, we employ click chemistry at room temperature to irreversibly bond polyimide and PDMS through thiol-epoxy bonds using two different methods. In the first method, we functionalize the surfaces of the PDMS and polyimide substrates with mercaptosilanes and epoxysilanes, respectively, for the formation of a thiol-epoxy bond in the click reaction. In the second method, we functionalize one or both surfaces with mercaptosilane and introduce an epoxy adhesive layer between the two surfaces. When the surfaces are bonded using the epoxy adhesive without any surface functionalization, an extremely small peel strength (<0.01 N mm −1 ) is measured with a peel test, and adhesive failure occurs at the PDMS surface. With surface functionalization, however, remarkably higher peel strengths of ∼0.2 N mm −1 (method 1) and  >0.3 N mm −1 (method 2) are observed, and failure occurs by tearing of the PDMS layer. We envision that the novel processing route employing click chemistry can be utilized in various cases of stretchable and flexible device fabrication. (paper)

  5. Sources and levels of radioactivity in the Philippine environment

    International Nuclear Information System (INIS)

    Duran, E.B.; De Vera, C.M.; De la Cruz, F.M.; Enriquez, E.B.; Garcia, T.Y.; Palad, L.H.; Enriquez, S.O.; Eduardo, J.M.; Asada, A.A.

    1996-01-01

    Over the years, the Health Physics Research Section has assessed the sources and levels of radiation exposure in the Philippine environment. The data show that although Filipinos are exposed to both natural and artificial sources of environmental radioactivity, natural sources contribute much more significantly to the dose received by Filipinos than artificial sources. The average equivalent dose rate due to external sources of natural radiation in the Philippines is 45 μSv h -1 . Of this total dose rate, an average of 22 μSv h -1 is due to cosmic radiation while an average of 23 μSv h -1 is due to terrestrial radiation. External sources of natural radiation in the Philippines thus account for an annual per caput effective dose of about 400 μSv. In contrast, the annual per caput dose due to an artificial source, i.e., nuclear power production, was estimated by UNSCEAR (1988) to be only 0.6 μSv. Based on levels of background radioactivity due to external sources of natural radiation which were measured in 1600 locations, a radiation map of the country was developed. Among the internal sources of natural radiation, radon is the large contributor to dose and is considered as a serious indoor pollutant. Indoor radon levels in about 400 Filipino houses ranged from 1 to 63 Bq m -3 with a mean of 24 Bq m -3 . Significantly higher levels ranging from 30 to 347 Bq m -3 were observed in underground, non-uranium mines. Since there are no operational nuclear power plant in the Philippines, artificial radionuclides in the environment consist mainly of long-lived 137 Cs and 90 Sr from atmospheric nuclear weapons tests

  6. Covalently {beta}-cyclodextrin modified single-walled carbon nanotubes: a novel artificial receptor synthesized by 'click' chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Guo Zhen; Liang Li [Nankai University, State Key Laboratory and Institute of Elemento-Organic Chemistry (China); Liang Jiajie; Ma Yanfeng; Yang Xiaoying [Nankai University, Center for Nanoscale Science and Technology and Institute of Polymer Chemistry, College of Chemistry (China); Ren Dongmei [Nankai University, State Key Laboratory and Institute of Elemento-Organic Chemistry (China); Chen Yongsheng [Nankai University, Center for Nanoscale Science and Technology and Institute of Polymer Chemistry, College of Chemistry (China); Zheng Jianyu, E-mail: jyzheng@nankai.edu.c [Nankai University, State Key Laboratory and Institute of Elemento-Organic Chemistry (China)

    2008-08-15

    Novel {beta}-cyclodextrin covalently modified single-walled carbon nanotubes have been synthesized via a 'click' coupling reaction. The product was fully characterized with Raman, FTIR, XRD, UV-Vis-NIR spectra as well as TEM and TGA measurements. The effective functionalization via 'click' coupling has set up a facile and versatile route for modular preparation of SWNTs based functional materials. The inclusion complexation behavior of this artificial receptor with quinine has been investigated in aqueous solution by fluorescence spectroscopy.

  7. Characterization of Yellow Seahorse Hippocampus kuda feeding click sound signals in a laboratory environment: an application of probability density function and power spectral density analyses

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.; Saran, A.K.; Kuncolienker, D.S.; Sreepada, R.A.; Haris, K.; Fernandes, W.A

    based on the assumption of combinations of normal / Gaussian distributions indicate well fitted multimodal curves generated using MATLAB (Math Works Inc 2005) programs. Out of the twenty three clicks, four clicks (two clicks of 16 and 18cm male... Society of America 115: 2331-2333. Malamud BD, Turcotte DL. 1999. Self affine time series: measures of weak and strong persistence. Journal of Statistical Planning and Inference 80:173-196. MATLAB, Curve Fitting toolbox, Math Works Inc 2005. Available...

  8. Efficient One-click Browsing of Large Trajectory Sets

    DEFF Research Database (Denmark)

    Krogh, Benjamin Bjerre; Andersen, Ove; Lewis-Kelham, Edwin

    2014-01-01

    presents a novel query type called sheaf, where users can browse trajectory data sets using a single mouse click. Sheaves are very versatile and can be used for location-based advertising, travel-time analysis, intersection analysis, and reachability analysis (isochrones). A novel in-memory trajectory...... index compresses the data by a factor of 12.4 and enables execution of sheaf queries in 40 ms. This is up to 2 orders of magnitude faster than existing work. We demonstrate the simplicity, versatility, and efficiency of sheaf queries using a real-world trajectory set consisting of 2.7 million...

  9. 'Click' dendritic phosphines: design, synthesis, application in Suzuki coupling, and recycling by nanofiltration

    NARCIS (Netherlands)

    Janssen, M.C.C.; Vogt, D.; Müller, C.

    2009-01-01

    A new synthetic route towards stable molecular-weight enlarged monodentate phosphine ligands via click chemistry was developed. These ligands were applied in the Pd-catalyzed Suzuki-Miyaura coupling of aryl halides and phenyl boronic acid. The supported systems show very similar activities compared

  10. Click & seed” approach to the biomimetic modification of material surfaces

    Czech Academy of Sciences Publication Activity Database

    Proks, Vladimír; Jaroš, J.; Pop-Georgievski, Ognen; Kučka, Jan; Popelka, Štěpán; Dvořák, P.; Hampl, A.; Rypáček, František

    2012-01-01

    Roč. 12, č. 9 (2012), s. 1232-1242 ISSN 1616-5187 R&D Projects: GA AV ČR KJB400500904; GA ČR GAP108/11/1857; GA MŠk 1M0538 Institutional research plan: CEZ:AV0Z40500505 Keywords : biomimetic modifications * click chemistry * peptide radiolabeling Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.742, year: 2012

  11. Evaluating and Optimizing Online Advertising: Forget the Click, but There Are Good Proxies.

    Science.gov (United States)

    Dalessandro, Brian; Hook, Rod; Perlich, Claudia; Provost, Foster

    2015-06-01

    Online systems promise to improve advertisement targeting via the massive and detailed data available. However, there often is too few data on exactly the outcome of interest, such as purchases, for accurate campaign evaluation and optimization (due to low conversion rates, cold start periods, lack of instrumentation of offline purchases, and long purchase cycles). This paper presents a detailed treatment of proxy modeling, which is based on the identification of a suitable alternative (proxy) target variable when data on the true objective is in short supply (or even completely nonexistent). The paper has a two-fold contribution. First, the potential of proxy modeling is demonstrated clearly, based on a massive-scale experiment across 58 real online advertising campaigns. Second, we assess the value of different specific proxies for evaluating and optimizing online display advertising, showing striking results. The results include bad news and good news. The most commonly cited and used proxy is a click on an ad. The bad news is that across a large number of campaigns, clicks are not good proxies for evaluation or for optimization: clickers do not resemble buyers. The good news is that an alternative sort of proxy performs remarkably well: observed visits to the brand's website. Specifically, predictive models built based on brand site visits-which are much more common than purchases-do a remarkably good job of predicting which browsers will make a purchase. The practical bottom line: evaluating and optimizing campaigns using clicks seems wrongheaded; however, there is an easy and attractive alternative-use a well-chosen site-visit proxy instead.

  12. Source Similarity and Social Media Health Messages: Extending Construal Level Theory to Message Sources.

    Science.gov (United States)

    Young, Rachel

    2015-09-01

    Social media users post messages about health goals and behaviors to online social networks. Compared with more traditional sources of health communication such as physicians or health journalists, peer sources are likely to be perceived as more socially close or similar, which influences how messages are processed. This experimental study uses construal level theory of psychological distance to predict how mediated health messages from peers influence health-related cognition and behavioral intention. Participants were exposed to source cues that identified peer sources as being either highly attitudinally and demographically similar to or different from participants. As predicted by construal level theory, participants who perceived sources of social media health messages as highly similar listed a greater proportion of beliefs about the feasibility of health behaviors and a greater proportion of negative beliefs, while participants who perceived sources as more dissimilar listed a greater proportion of positive beliefs about the health behaviors. Results of the study could be useful in determining how health messages from peers could encourage individuals to set realistic health goals.

  13. Ultra-Fast RAFT-HDA Click Conjugation: An Efficient Route to High Molecular Weight Block Copolymers.

    Science.gov (United States)

    Inglis, Andrew J; Stenzel, Martina H; Barner-Kowollik, Christopher

    2009-11-02

    The use of the reversible addition fragmentation chain transfer-hetero Diels-Alder (RAFT-HDA) click reaction for the modular construction of block copolymers is extended to the generation of high molecular weight materials. Cyclopentadienyl end-functionalized polystyrene (PS-Cp) prepared via both atom transfer radical polymerization (ATRP) and the RAFT process are conjugated to poly(isobornyl acrylate) (PiBoA) (also prepared via RAFT polymerization) to achieve well-defined block copolymers with molecular weights ranging from 34 000 to over 100 000 g · mol(-1) and with small polydispersities (PDI HDA click chemistry can provide access to high molecular weight block copolymers in a simple and straight-forward fashion. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. One-step fabrication of PEGylated fluorescent nanodiamonds through the thiol-ene click reaction and their potential for biological imaging

    Science.gov (United States)

    Huang, Hongye; Liu, Meiying; Tuo, Xun; Chen, Junyu; Mao, Liucheng; Wen, Yuanqing; Tian, Jianwen; Zhou, Naigen; Zhang, Xiaoyong; Wei, Yen

    2018-05-01

    Over the past years, fluorescent carbon nanoparticles have got growing interest for biological imaging. Fluorescent nanodiamonds (FNDs) are novel fluorescent carbon nanoparticles with multitudinous useful properties, including remarkable fluorescence properties, extremely low toxicity and high refractive index. However, facile preparation of FNDs with designable properties and functions from non-fluorescent detonation nanodiamonds (DNDs) has demonstrated to be challengeable. In this work, we reported for the first time that preparation of Polyethylene glycol (PEG) functionalized FNDs through a one-step thiol-ene click reaction using thiol containing PEG (PEG-SH) as the coating agent. Based on the characterization results, we demonstrated that PEG-SH could be efficiently introduced on DNDs to obtain FNDs through the thiol-ene click chemistry. The resultant FND-PEG composites showed high water dispersibility, strong fluorescence and low cytotoxicity. Moreover, FND-PEG composites could be internalized by cells and displayed good cell dyeing performance. All of these features implied that FND-PEG composites are of great potential for biological imaging. Taken together, a facile one-step strategy based on the one-step thiol-ene click reaction has been developed for efficient preparation of FND-PEG composites from non-fluorescent DNDs. The strategy should be also useful for fabrication of many other functional FNDs via using different thiol containing compounds for the universality of thiol-ene click reaction.

  15. Hydrophobic Coatings by Thiol-Ene Click Functionalization of Silsesquioxanes with Tunable Architecture.

    Science.gov (United States)

    Dirè, Sandra; Bottone, Davide; Callone, Emanuela; Maniglio, Devid; Génois, Isabelle; Ribot, François

    2017-08-08

    The hydrolysis-condensation of trialkoxysilanes under strictly controlled conditions allows the production of silsesquioxanes (SSQs) with tunable size and architecture ranging from ladder to cage-like structures. These nano-objects can serve as building blocks for the preparation of hybrid organic/inorganic materials with selected properties. The SSQs growth can be tuned by simply controlling the reaction duration in the in situ water production route (ISWP), where the kinetics of the esterification reaction between carboxylic acids and alcohols rules out the extent of organosilane hydrolysis-condensation. Tunable SSQs with thiol functionalities (SH-NBBs) are suitable for further modification by exploiting the simple thiol-ene click reaction, thus allowing for modifying the wettability properties of derived coatings. In this paper, coatings were prepared from SH-NBBs with different architecture onto cotton fabrics and paper, and further functionalized with long alkyl chains by means of initiator-free UV-induced thiol-ene coupling with 1-decene (C10) and 1-tetradecene (C14). The coatings appeared to homogeneously cover the natural fibers and imparted a multi-scale roughness that was not affected by the click functionalization step. The two-step functionalization of cotton and paper warrants a stable highly hydrophobic character to the surface of natural materials that, in perspective, suggests a possible application in filtration devices for oil-water separation. Furthermore, the purification of SH-NBBs from ISWP by-products was possible during the coating process, and this step allowed for the fast, initiator-free, click-coupling of purified NBBs with C10 and C14 in solution with a nearly quantitative yield. Therefore, this approach is an alternative route to get sol-gel-derived, ladder-like, and cage-like SSQs functionalized with long alkyl chains.

  16. Analysis of internet advertisement type PPC (Pay-Per-Click) in concrete firm (Cedar home)

    OpenAIRE

    Krausová, Lenka

    2009-01-01

    The aim of this bachelor thesis is to present the features of internet advertising. The main type of advertisement in this thesis is called PPC (Pay-Per-Click). There are created and advertised advertising campaigns on concrete project.

  17. Comparative case study on website traffic generated by search engine optimisation and a pay-per-click campaign, versus marketing expenditure

    Directory of Open Access Journals (Sweden)

    Wouter T. Kritzinger

    2015-09-01

    Full Text Available Background: No empirical work was found on how marketing expenses compare when used solely for either the one or the other of the two main types of search engine marketing. Objectives: This research set out to determine how the results of the implementation of a pay-per-click campaign compared to those of a search engine optimisation campaign, given the same website and environment. At the same time, the expenses incurred on both these marketing methods were recorded and compared. Method: The active website of an existing, successful e-commerce concern was used as platform. The company had been using pay-per-click only for a period, whilst traffic was monitored. This system was decommissioned on a particular date and time, and an alternative search engine optimisation system was started at the same time. Again, both traffic and expenses were monitored. Results: The results indicate that the pay-per-click system did produce favourable results, but on the condition that a monthly fee has to be set aside to guarantee consistent traffic. The implementation of search engine optimisation required a relatively large investment at the outset, but it was once-off. After a drop in traffic owing to crawler visitation delays, the website traffic bypassed the average figure achieved during the pay-per-click period after a little over three months, whilst the expenditure crossed over after just six months. Conclusion: Whilst considering the specific parameters of this study, an investment in search engine optimisation rather than a pay-per-click campaign appears to produce better results at a lower cost, after a given period of time. [PDF to follow

  18. Synthesis of a hexasaccharide partial sequence of hyaluronan for click chemistry and more

    Directory of Open Access Journals (Sweden)

    Marina Bantzi

    2015-04-01

    Full Text Available In the present work, the synthesis of a hexasaccharide partial sequence of hyaluronan equipped with a terminal azido moiety is reported. This hexasaccharide can be used for the attachment on surfaces by means of click chemistry and after suitable deprotection for biophysical studies.

  19. Global Sourcing: Evidence from Spanish Firm-level Data

    DEFF Research Database (Denmark)

    Kohler, Wilhelm; Smolka, Marcel

    2012-01-01

    We investigate the link between productivity of firms and their sourcing behavior. Following Antràs and Helpman (2004) we distinguish between domestic and foreign sourcing, as well as between outsourcing and vertical integration. A firm's choice is driven by a hold-up problem caused by lack of en...... of enforceable contracts. We use Spanish firm-level data to examine the productivity premia associated with the different sourcing strategies....

  20. Low-level waste disposal performance assessments - Total source-term analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wilhite, E.L.

    1995-12-31

    Disposal of low-level radioactive waste at Department of Energy (DOE) facilities is regulated by DOE. DOE Order 5820.2A establishes policies, guidelines, and minimum requirements for managing radioactive waste. Requirements for disposal of low-level waste emplaced after September 1988 include providing reasonable assurance of meeting stated performance objectives by completing a radiological performance assessment. Recently, the Defense Nuclear Facilities Safety Board issued Recommendation 94-2, {open_quotes}Conformance with Safety Standards at Department of Energy Low-Level Nuclear Waste and Disposal Sites.{close_quotes} One of the elements of the recommendation is that low-level waste performance assessments do not include the entire source term because low-level waste emplaced prior to September 1988, as well as other DOE sources of radioactivity in the ground, are excluded. DOE has developed and issued guidance for preliminary assessments of the impact of including the total source term in performance assessments. This paper will present issues resulting from the inclusion of all DOE sources of radioactivity in performance assessments of low-level waste disposal facilities.

  1. Hearing impairment in children with congenital cytomegalovirus (CMV) infection based on distortion product otoacoustic emissions (DPOAE) and brain evoked response audiometry stimulus click (BERA Click) examinations

    Science.gov (United States)

    Airlangga, T. J.; Mangunatmadja, I.; Prihartono, J.; Zizlavsky, S.

    2017-08-01

    Congenital cytomegalovirus (congenital CMV) infection is a leading factor of nongenetic sensorineural hearing loss in children. Hearing loss caused by CMV infection does not have a pathognomonic configuration hence further research is needed. The development of knowledge on hearing loss caused by congenital CMV infection is progressing in many countries. Due to a lack of research in the context of Indonesia, this study assesses hearing impairment in children with congenital CMV infection in Indonesia, more specifically in the Cipto Mangunkusumo Hospital. Our objective was to profile hearing impairment in children 0-5 years of age with congenital CMV infection using Distortion Product Otoacoustic Emissions (DPOAE) and Brain Evoked Response Audiometry Stimulus Click (BERA Click) examinations. This cross-sectional study was conducted in the Cipto Mangunkusum Hospital from November, 2015 to May 2016 with 27 children 0-5 years of age with congenital CMV infection. Of individual ears studied, 58.0% exhibited sensorineural hearing loss. There was a significant relationship between developmental delay and incidence of sensorineural hearing loss. Subjects with a developmental delay were 6.57 times more likely (CI 95%; 1.88-22.87) to experience sensorineural hearing loss. Congenital CMV infection has an important role in causing sensorineural hearing loss in children.

  2. In Situ Forming, Cytocompatible, and Self-Recoverable Tough Hydrogels Based on Dual Ionic and Click Cross-Linked Alginate.

    Science.gov (United States)

    Ghanian, Mohammad Hossein; Mirzadeh, Hamid; Baharvand, Hossein

    2018-05-14

    A dual cross-linking strategy was developed to answer the urgent need for fatigue-resistant, cytocompatible, and in situ forming tough hydrogels. Clickable, yet calcium-binding derivatives of alginate were synthesized by partial substitution of its carboxyl functionalities with furan, which could come into Diels-Alder click reaction with maleimide end groups of a four arm poly(ethylene glycol) cross-linker. Tuning the cooperative viscoelastic action of transient ionic and permanent click cross-links within the single network of alginate provided a soft tough hydrogel with a set of interesting features: (i) immediate self-recovery under cyclic loading, (ii) highly efficient and autonomous self-healing upon fracture, (iii) in situ forming ability for molding and minimally invasive injection, (iv) capability for viable cell encapsulation, and (v) reactivity for on-demand biomolecule conjugation. The facile strategy is applicable to a wide range of natural and synthetic polymers by introducing the calcium binding and click reacting functional groups and can broaden the use of tough hydrogels in load-bearing, cell-laden applications such as soft tissue engineering and bioactuators.

  3. A New Modular Approach to Nanoassembly: Stable and Addressable DNA Nanoconstructs via Orthogonal Click Chemistries

    KAUST Repository

    Gerrard, Simon R.

    2012-10-23

    Thermodynamic instability is a problem when assembling and purifying complex DNA nanostructures formed by hybridization alone. To address this issue, we have used photochemical fixation and orthogonal copper-free, ring-strain-promoted, click chemistry for the synthesis of dimeric, trimeric, and oligomeric modular DNA scaffolds from cyclic, double-stranded, 80-mer DNA nanoconstructs. This particular combination of orthogonal click reactions was more effective for nanoassembly than others explored. The complex nanostructures are stable to heat and denaturation agents and can therefore be purified and characterized. They are addressable in a sequence-specific manner by triplex formation, and they can be reversibly and selectively deconstructed. Nanostructures utilizing this orthogonal, chemical fixation methodology can be used as building blocks for nanomachines and functional DNA nanoarchitectures. © 2012 American Chemical Society.

  4. A New Modular Approach to Nanoassembly: Stable and Addressable DNA Nanoconstructs via Orthogonal Click Chemistries

    KAUST Repository

    Gerrard, Simon R.; Hardiman, Claire; Shelbourne, Montserrat; Nandhakumar, Iris; Nordé n, Bengt; Brown, Tom

    2012-01-01

    chemistry for the synthesis of dimeric, trimeric, and oligomeric modular DNA scaffolds from cyclic, double-stranded, 80-mer DNA nanoconstructs. This particular combination of orthogonal click reactions was more effective for nanoassembly than others explored

  5. C,N-Chelated Organotin(IV) Azides: Synthesis, Structure and Use within the Click Chemistry.

    Czech Academy of Sciences Publication Activity Database

    Švec, P.; Bartoš, K.; Růžičková, Z.; Cuřínová, Petra; Dušek, L.; Turek, J.; de Proft, F.; Růžička, A.

    2016-01-01

    Roč. 40, č. 7 (2016), s. 5808-5817 ISSN 1144-0546 Grant - others:FWO(BE) 12T6615N Institutional support: RVO:67985858 Keywords : organotin(IV)azides * click chemistry * chelation Subject RIV: CC - Organic Chemistry Impact factor: 3.269, year: 2016

  6. pH responsive label-assisted click chemistry triggered sensitivity amplification for ultrasensitive electrochemical detection of carbohydrate antigen 24-2.

    Science.gov (United States)

    Zheng, Yun; Zhao, Lihua; Ma, Zhanfang

    2018-05-15

    Sensitivity amplification strategy by implementing click chemistry in the construction of biosensing interface can efficiently improve the performance of immunosensor. Herein, we developed a sandwich-type amperometric immunosensor for ultrasensitive detection of carbohydrate antigen 24-2 (CA 242) based on pH responsive label-assisted click chemistry triggered sensitivity amplification strategy. The sensitivity of amperometric immunosensor relies on the current response differences (ΔI) caused by per unit concentration target analyte. The pH responsive Cu 2+ -loaded polydopamine (CuPDA) particles conjugated with detection antibodies were employed as labels, which can release Cu(II) ions by regulating pH. In the presence of ascorbic acid (reductant), Cu(II) ions were reduced to Cu(I) ions. Azide-functionalized double-stranded DNA (dsDNA) as signal enhancer was immobilized on the substrate through Cu + -catalyzed azide/alkyne cycloaddition reaction. With the help of the click reaction, the ΔI caused by target was elevated prominently, resulting in sensitivity amplification of the immunosensor. Under optimal condition, the proposed immunosensor exhibited excellent performance with linear range from 0.0001 to 100 U mL -1 and ultralow detection limit of 20.74 μU mL -1 . This work successfully combines click chemistry with pH-responsive labels in sandwich-type amperometric immunosensor, providing a promising sensitivity amplification strategy to construct immunosensing platform for analysis of other tumor marker. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Why are there no long distance jumpers among click-beetles (Elateridae)?

    International Nuclear Information System (INIS)

    Ribak, Gal; Mordechay, Oded; Weihs, Daniel

    2013-01-01

    Click-beetles jump from an inverted position without using their legs. This unique mechanism results in high vertical jumps with the jump angle restricted by the rigid morphology of the exoskeleton. We explored the option to exploit this jumping mechanism for application to small mechanical devices having to extricate themselves from rough terrain. We combined experiments on a biomimetic jumping device with a physical–mathematical model of the jump to assess the effect of morphological variation on the jumping performance. We found that through morphological change of two non-dimensional (size independent) parameters, the propulsive force powering the jump can be directed at angles as small as 40°. However, in practice jumping at such angles is precluded by loss of traction with the ground during the push-off phase. This limitation to steep jump angles is inherent to the jumping mechanism which is based on rotation of body parts about a single hinge. Such a rotation dictates a curvilinear trajectory for the center of mass during takeoff so that the vertical and horizontal accelerations occur out of phase, implying loss of traction with the ground before substantial horizontal acceleration can be reached. Thus click-beetle inspired jumping is effective mainly for making steep-angle righting jumps. (paper)

  8. Purification and identification of O-GlcNAc-modified peptides using phosphate-based alkyne CLICK chemistry in combination with titanium dioxide chromatography and mass spectrometry

    DEFF Research Database (Denmark)

    Parker, Benjamin L; Gupta, Pankaj; Cordwell, Stuart

    2011-01-01

    A selective method for the enrichment of O-GlcNAcylated peptides using a novel CLICK chemistry reagent is described. Peptides modified by O-GlcNAc were enzymatically labeled with N-azidoacetylgalactosamine. The azide was then reacted with a phospho-alkyne using CLICK chemistry and O-GlcNAcGalNAzPO4...

  9. A Source-level Energy Optimization Framework for Mobile Applications

    DEFF Research Database (Denmark)

    Li, Xueliang; Gallagher, John Patrick

    2016-01-01

    strategies. The framework also lays a foundation for the code optimization by automatic tools. To the best of our knowledge, our work is the first that achieves this for a high-level language such as Java. In a case study, the experimental evaluation shows that our approach is able to save from 6.4% to 50...... process. The source code is the interface between the developer and hardware resources. In this paper, we propose an energy optimization framework guided by a source code energy model that allows developers to be aware of energy usage induced by the code and to apply very targeted source-level refactoring...

  10. Evaluation of the May 2005 Click It or Ticket mobilization to increase seat belt use

    Science.gov (United States)

    2007-05-01

    Click It or Ticket (CIOT) is an intense, short-duration, seat belt publicity and enforcement program. The CIOT May 2005 Mobilization involved approximately $33 million of purchased media. Law enforcement agencies across the Nation reported issuing mo...

  11. Detection of Alkynes via Click Chemistry with a Brominated Coumarin Azide by Simultaneous Fluorescence and Isotopic Signatures in Mass Spectrometry.

    Science.gov (United States)

    Yang, Lihua; Chumsae, Chris; Kaplan, Jenifer B; Moulton, Kevin Ryan; Wang, Dongdong; Lee, David H; Zhou, Zhaohui Sunny

    2017-09-20

    Alkynes are a key component of click chemistry and used for a wide variety of applications including bioconjugation, selective tagging of protein modifications, and labeling of metabolites and drug targets. However, challenges still exist for detecting alkynes because most 1,2,3-triazole products from alkynes and azides do not possess distinct intrinsic properties that can be used for their facile detection by either fluorescence or mass spectrometry. To address this critical need, a novel brominated coumarin azide was used to tag alkynes and detect alkyne-conjugated biomolecules. This tag has several useful properties: first, it is fluorogenic and the click-chemistry products are highly fluorescent and quantifiable; second, its distinct isotopic pattern facilitates identification by mass spectrometry; and third, its click-chemistry products form a unique pair of reporter ions upon fragmentation that can be used for the quick screening of data. Using a monoclonal antibody conjugated with alkynes, a general workflow has been developed and examined comprehensively.

  12. Predicting Click-Through Rates of New Advertisements Based on the Bayesian Network

    Directory of Open Access Journals (Sweden)

    Zhipeng Fang

    2014-01-01

    Full Text Available Most classical search engines choose and rank advertisements (ads based on their click-through rates (CTRs. To predict an ad’s CTR, historical click information is frequently concerned. To accurately predict the CTR of the new ads is challenging and critical for real world applications, since we do not have plentiful historical data about these ads. Adopting Bayesian network (BN as the effective framework for representing and inferring dependencies and uncertainties among variables, in this paper, we establish a BN-based model to predict the CTRs of new ads. First, we built a Bayesian network of the keywords that are used to describe the ads in a certain domain, called keyword BN and abbreviated as KBN. Second, we proposed an algorithm for approximate inferences of the KBN to find similar keywords with those that describe the new ads. Finally based on the similar keywords, we obtain the similar ads and then calculate the CTR of the new ad by using the CTRs of the ads that are similar with the new ad. Experimental results show the efficiency and accuracy of our method.

  13. [Value of condensation and rarefaction click evoked action potential latency difference in the diagnosis of Meniere's disease].

    Science.gov (United States)

    Wang, Z; Shao, X; Yan, W; Lin, H

    2000-06-01

    To study the value of condensation and rarefaction clicks evoked action potential (AP) latency difference (LD) in diagnosis of Meniere's disease. AP was recorded with ECochG in controls (50 ears) and patients with Meniere's disease(90 ears) and sensorineural hearing loss(SNHL) of other origins(60 ears). LD was calculated and analyzed. LD in patients with Meniere's disease was (0.30 +/- 0.15) ms, which was significantly larger than that of controls(0.18 +/- 0.07) ms and of patients with SNHL of other origins(0.20 +/- 0.10) ms (P curve was larger than those with flat auditory sensation curve(P rarefaction click evoked AP latency difference can be an objective parameter in diagnosis of Meniere's disease.

  14. Evaluating forensic biology results given source level propositions.

    Science.gov (United States)

    Taylor, Duncan; Abarno, Damien; Hicks, Tacha; Champod, Christophe

    2016-03-01

    The evaluation of forensic evidence can occur at any level within the hierarchy of propositions depending on the question being asked and the amount and type of information that is taken into account within the evaluation. Commonly DNA evidence is reported given propositions that deal with the sub-source level in the hierarchy, which deals only with the possibility that a nominated individual is a source of DNA in a trace (or contributor to the DNA in the case of a mixed DNA trace). We explore the use of information obtained from examinations, presumptive and discriminating tests for body fluids, DNA concentrations and some case circumstances within a Bayesian network in order to provide assistance to the Courts that have to consider propositions at source level. We use a scenario in which the presence of blood is of interest as an exemplar and consider how DNA profiling results and the potential for laboratory error can be taken into account. We finish with examples of how the results of these reports could be presented in court using either numerical values or verbal descriptions of the results. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. A formal treatment of uncertainty sources in a level 2 PSA

    International Nuclear Information System (INIS)

    Ahn, Kwang Il; Yang, Joon Eon

    2003-01-01

    The methodological framework of the level 2 PSA appears to be currently standardized in a formalized fashion, but there have been different opinions on the way the sources of uncertainty are characterized and treated. This is primarily because the level 2 PSA deals with complex phenomenological processes that are deterministic in nature rather than random processes, and there are no probabilistic models characterizing them clearly. As a result, the probabilistic quantification of the level 2 PSA is often subjected to two sources of uncertainty: (a) incomplete modeling of accident pathways or different predictions for the behavior of phenomenological events and (b) expert-to-expert variation in estimating the occurrence probability of phenomenological events. While a clear definition of the two sources of uncertainty involved in the level 2 PSA makes it possible to treat an uncertainty in a consistent manner, careless application of these different sources of uncertainty may produce different conclusions in the decision-making process. The primary purpose of this paper is to characterize typical sources of uncertainty that would often be addressed in the level 2 PSA and their impacts on the PSA level 2 risk results. An additional purpose of this paper is to give a formal approach on how to combine random uncertainties addressed in the level 1 PSA with subjectivistic uncertainties addressed in the level 2 PSA

  16. Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II-ethylenediamine precatalyst

    Directory of Open Access Journals (Sweden)

    Redouane Beniazza

    2015-10-01

    Full Text Available The search for copper catalysts able to perform effectively click reactions in water in the absence of sodium ascorbate is an active area of current research with strong potential for applications in bioconjugation. The water-soluble and photoreducible copper(II–EDA (EDA = ethylenediamine complex 1, which has two 4-benzoylbenzoates acting as both counterion and photosensitizer, has been synthesized and characterized by different techniques including single crystal X-ray diffraction. Highly efficient photoreduction was demonstrated when solutions of 1 in hydrogen atom donating solvents, such as THF or MeOH, were exposed to UVA radiation (350–400 nm provided by a low pressure mercury lamp (type TLC = thin-layer chromatography, 365 nm, or by a 23 W fluorescent bulb, or by ambient/sunlight. In water, a much poorer hydrogen atom donating solvent, the photoreduction of 1 proved inefficient. Interestingly, EPR studies revealed that complex 1 could nonetheless be effectively photoreduced in water when alkynes were present in solution. The catalytic activity of 1 for click reactions involving a range of water-soluble alkynes and azides, in particular saccharides, was tested under various illumination conditions. Complex 1 was found to exhibit a photolatent character, the photogenerated copper(I being very reactive. On irradiating aqueous reaction mixtures containing 1 mol % of 1 at 365 nm (TLC lamp for 1 h, click reactions were shown to proceed to full conversion.

  17. Neural Point-and-Click Communication by a Person With Incomplete Locked-In Syndrome.

    Science.gov (United States)

    Bacher, Daniel; Jarosiewicz, Beata; Masse, Nicolas Y; Stavisky, Sergey D; Simeral, John D; Newell, Katherine; Oakley, Erin M; Cash, Sydney S; Friehs, Gerhard; Hochberg, Leigh R

    2015-06-01

    A goal of brain-computer interface research is to develop fast and reliable means of communication for individuals with paralysis and anarthria. We evaluated the ability of an individual with incomplete locked-in syndrome enrolled in the BrainGate Neural Interface System pilot clinical trial to communicate using neural point-and-click control. A general-purpose interface was developed to provide control of a computer cursor in tandem with one of two on-screen virtual keyboards. The novel BrainGate Radial Keyboard was compared to a standard QWERTY keyboard in a balanced copy-spelling task. The Radial Keyboard yielded a significant improvement in typing accuracy and speed-enabling typing rates over 10 correct characters per minute. The participant used this interface to communicate face-to-face with research staff by using text-to-speech conversion, and remotely using an internet chat application. This study demonstrates the first use of an intracortical brain-computer interface for neural point-and-click communication by an individual with incomplete locked-in syndrome. © The Author(s) 2014.

  18. Assembly of a biocompatible triazole-linked gene by one-pot click-DNA ligation

    Science.gov (United States)

    Kukwikila, Mikiembo; Gale, Nittaya; El-Sagheer, Afaf H.; Brown, Tom; Tavassoli, Ali

    2017-11-01

    The chemical synthesis of oligonucleotides and their enzyme-mediated assembly into genes and genomes has significantly advanced multiple scientific disciplines. However, these approaches are not without their shortcomings; enzymatic amplification and ligation of oligonucleotides into genes and genomes makes automation challenging, and site-specific incorporation of epigenetic information and/or modified bases into large constructs is not feasible. Here we present a fully chemical one-pot method for the assembly of oligonucleotides into a gene by click-DNA ligation. We synthesize the 335 base-pair gene that encodes the green fluorescent protein iLOV from ten functionalized oligonucleotides that contain 5ʹ-azide and 3ʹ-alkyne units. The resulting click-linked iLOV gene contains eight triazoles at the sites of chemical ligation, and yet is fully biocompatible; it is replicated by DNA polymerases in vitro and encodes a functional iLOV protein in Escherichia coli. We demonstrate the power and potential of our one-pot gene-assembly method by preparing an epigenetically modified variant of the iLOV gene.

  19. Chronological changes in the eighth cranial nerve compound action potential (CAP) in experimental endolymphatic hydrops: the effects of altering the polarity of click sounds.

    Science.gov (United States)

    Morizono, Tetsuo; Kondo, Tsuyoshi; Yamano, Takafumi; Miyagi, Morimichi; Shiraishi, Kimio

    2009-02-01

    Using a guinea pig model of experimental endolymphatic hydrops, click sounds of altered polarity showed different latencies and amplitudes in hydropic compared with normal cochleae. Latency changes appeared as early as 1 week after endolymphatic obstruction. This method can help diagnose endolymphatic hydrops. The goal of the study was to develop an objective electrophysiological diagnosis of endolymphatic hydrops. Endolymphatic hydrops were created surgically in guinea pigs. The latency and the amplitude of the eighth cranial nerve compound action potential (CAP) for click sounds of altered polarity were measured up to 8 weeks after the surgery. At early stages after surgery, the latency for condensation clicks became longer, and at later stages the latencies for both condensation and rarefaction became longer. The discrepancy in the latencies for rarefaction and condensation click sounds (rarefaction minus condensation) became larger by the first week after surgery, but no further discrepancy occurred thereafter. Compared with latency changes, amplitude changes in the CAP were rapid and progressive following surgery, suggesting ongoing damage to hair cells.

  20. Phylogenetic relationships of click beetles (Coleoptera: Elateridae) inferred from 28S ribosomal DNA: insights into the evolution of bioluminescence in Elateridae.

    Science.gov (United States)

    Sagegami-Oba, Reiko; Oba, Yuichi; Ohira, Hitoo

    2007-02-01

    Although the taxonomy of click beetles (family Elateridae) has been studied extensively, inconsistencies remain. We examine here the relationships between species of Elateridae based on partial sequences of nuclear 28S ribosomal DNA. Specimens were collected primarily from Japan, while luminous click beetles were also sampled from Central and South America to investigate the origins of bioluminescence in Elateridae. Neighbor-joining, maximum-parsimony, and maximum-likelihood analyses produced a consistent basal topology with high statistical support that is partially congruent with the results of previous investigations based on the morphological characteristics of larvae and adults. The most parsimonious reconstruction of the "luminous" and "nonluminous" states, based on the present molecular phylogeny, indicates that the ancestral state of Elateridae was nonluminous. This suggests that the bioluminescence in click beetle evolved independent of that of other luminous beetles, such as Lampyridae, despite their common mechanisms of bioluminescence.

  1. An Efficient and Straightforward Method for Radiolabeling of Nanoparticles with {sup 64}Cu via Click Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Eun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Kim, Kwangmeyung [Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology (KIST), Seoul 136-791 (Korea, Republic of); Park, Sang Hyun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185 (Korea, Republic of); Department of Radiobiotechnology and Applied Radioisotope Science, Korea University of Science and Technology, Deajeon 305-350 (Korea, Republic of)

    2015-07-01

    Recently, nanoparticles have received a great deal of interest in diagnosis and therapy applications. Since nanoparticles possess intrinsic features that are often required for a drug delivery system and diagnosis, they have potential to be used as platforms for integrating imaging and therapeutic functions, simultaneously. Intrinsic issues that are associated with theranostic nanoparticles, particularly in cancer treatment, include an efficient and straightforward radiolabeling method for understanding the in vivo biodistribution of nanoparticles to reach the tumor region, and monitoring therapeutic responses. Herein, we investigated a facile and highly efficient strategy to prepare radiolabeled nanoparticles with {sup 64}Cu via a strain-promoted azide, i.e., an alkyne cycloaddition strategy, which is often referred to as click chemistry. First, the azide (N3) group, which allows for the preparation of radiolabeled nanoparticles by copper-free click chemistry, was incorporated into glycol chitosan nanoparticles (CNPs). Second, the strained cyclooctyne derivative, dibenzyl cyclooctyne (DBCO) conjugated with a 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid (DOTA) chelator, was synthesized for preparing the pre-radiolabeled alkyne complex with {sup 64}Cu radionuclide. Following incubation with the {sup 64}Cu-radiolabeled DBCO complex (DBCO-PEG4-Lys-DOTA-{sup 64}Cu with high specific activity, 18.5 GBq/μ mol), the azide-functionalized CNPs were radiolabeled successfully with {sup 64}Cu, with a high radiolabeling efficiency and a high radiolabeling yield (>98%). Importantly, the radiolabeling of CNPs by copper-free click chemistry was accomplished within 30 min, with great efficiency in aqueous conditions. After {sup 64}Cu-CNPs were intravenously administered to tumor-bearing mice, the real time, in vivo biodistribution and tumor-targeting ability of {sup 64}Cu-CNPs were quantitatively evaluated by micro-PET images of tumor-bearing mice. These results

  2. General method for labeling siRNA by click chemistry with fluorine-18 for the purpose of PET imaging.

    Science.gov (United States)

    Mercier, Frédéric; Paris, Jérôme; Kaisin, Geoffroy; Thonon, David; Flagothier, Jessica; Teller, Nathalie; Lemaire, Christian; Luxen, André

    2011-01-19

    The alkyne-azide Cu(I)-catalyzed Huisgen cycloaddition, a click-type reaction, was used to label a double-stranded oligonucleotide (siRNA) with fluorine-18. An alkyne solid support CPG for the preparation of monostranded oligonucleotides functionalized with alkyne has been developed. Two complementary azide labeling agents (1-(azidomethyl)-4-[(18)F]fluorobenzene) and 1-azido-4-(3-[(18)F]fluoropropoxy)benzene have been produced with 41% and 35% radiochemical yields (decay-corrected), respectively. After annealing with the complementary strand, the siRNA was directly labeled by click chemistry with [(18)F]fluoroazide to produce the [(18)F]-radiolabeled siRNA with excellent radiochemical yield and purity.

  3. Functionalization of multilayer fullerenes (carbon nano-onions) using diazonium compounds and "click" chemistry.

    Science.gov (United States)

    Flavin, Kevin; Chaur, Manuel N; Echegoyen, Luis; Giordani, Silvia

    2010-02-19

    A novel versatile approach for the functionalization of multilayer fullerenes (carbon nano-onions) has been developed, which involves the facile introduction of a variety of simple functionalities onto their surface by treatment with in situ generated diazonium compounds. This approach is complemented by use of "click" chemistry which was used for the covalent introduction of more complex porphyrin molecules.

  4. Click synthesis of 1,4-disubstituted-1,2,3-triazoles catalysed by CuO ...

    Indian Academy of Sciences (India)

    Click synthesis of 1,4-disubstituted-1,2,3-triazoles catalysed by. CuO–CeO2 nanocomposite in the presence of amberlite-supported azide. JALAL ALBADIa,∗, JAFAR ABBASI SHIRANb and AZAM MANSOURNEZHADc. aBehbahan Khatam Alanbia University of Technology, Behbahan 6361647189, Iran. bFaculty of Science ...

  5. Contamination levels of domestic water sources in Maiduguri ...

    African Journals Online (AJOL)

    The study examines the levels of contamination of domestic water sources in Maiduguri Metropolis area of Borno State based on their physicochemical and bacteriological properties. It was informed by the global concern on good drinking water quality which is an indicator of development level; hence the focus on domestic ...

  6. Direct imaging of glycans in Arabidopsis roots via click labeling of metabolically incorporated azido-monosaccharides.

    Science.gov (United States)

    Hoogenboom, Jorin; Berghuis, Nathalja; Cramer, Dario; Geurts, Rene; Zuilhof, Han; Wennekes, Tom

    2016-10-10

    Carbohydrates, also called glycans, play a crucial but not fully understood role in plant health and development. The non-template driven formation of glycans makes it impossible to image them in vivo with genetically encoded fluorescent tags and related molecular biology approaches. A solution to this problem is the use of tailor-made glycan analogs that are metabolically incorporated by the plant into its glycans. These metabolically incorporated probes can be visualized, but techniques documented so far use toxic copper-catalyzed labeling. To further expand our knowledge of plant glycobiology by direct imaging of its glycans via this method, there is need for novel click-compatible glycan analogs for plants that can be bioorthogonally labelled via copper-free techniques. Arabidopsis seedlings were incubated with azido-containing monosaccharide analogs of N-acetylglucosamine, N-acetylgalactosamine, L-fucose, and L-arabinofuranose. These azido-monosaccharides were metabolically incorporated in plant cell wall glycans of Arabidopsis seedlings. Control experiments indicated active metabolic incorporation of the azido-monosaccharide analogs into glycans rather than through non-specific absorption of the glycan analogs onto the plant cell wall. Successful copper-free labeling reactions were performed, namely an inverse-electron demand Diels-Alder cycloaddition reaction using an incorporated N-acetylglucosamine analog, and a strain-promoted azide-alkyne click reaction. All evaluated azido-monosaccharide analogs were observed to be non-toxic at the used concentrations under normal growth conditions. Our results for the metabolic incorporation and fluorescent labeling of these azido-monosaccharide analogs expand the possibilities for studying plant glycans by direct imaging. Overall we successfully evaluated five azido-monosaccharide analogs for their ability to be metabolically incorporated in Arabidopsis roots and their imaging after fluorescent labeling. This expands

  7. INBOUND AND OUTBOUND MARKETING TECHNIQUES: A COMPARISON BETWEEN ITALIAN AND ROMANIAN PURE PLAYERS AND CLICK AND MORTAR COMPANIES

    Directory of Open Access Journals (Sweden)

    Elisa Rancati

    2015-05-01

    Full Text Available Despite the large number of blog posts and articles regarding the use of Inbound and Outbound Marketing techniques, no research articles compares the propensity of companies towards these opposite types of marketing techniques among different countries. The present study is mainly focused on literature review of Inbound vs Outbound Marketing and acknowledge the academic community, interested in Content Marketing studies, about the availability of data sets regarding the implementation of these techniques at the level of Italian and Romanian pure players and click and mortar companies, which will be explored in the near future through appropriate statistical methods within the framework of a cross-cultural research.

  8. Comparação dos estímulos clique e CE-chirp® no registro do Potencial Evocado Auditivo de Tronco Encefálico Comparison of click and CE-chirp® stimuli on Brainstem Auditory Evoked Potential recording

    Directory of Open Access Journals (Sweden)

    Gabriela Ribeiro Ivo Rodrigues

    2012-12-01

    Full Text Available OBJETIVO: Comparar as latências e as amplitudes da onda V no registro do Potencial Evocado Auditivo de Tronco Encefálico (PEATE com os estímulos clique e CE-chirp® e a presença ou ausência das ondas I, III e V em fortes intensidades. MÉTODOS: Estudo transversal com 12 adultos com limiares audiométricos PURPOSE: To compare the latencies and amplitudes of wave V on the Brainstem Auditory Evoked Potential (BAEP recording obtained with click and CE-chirp® stimuli and the presence or absence of waves I, III and V in high intensities. METHODS: Cross-sectional study with 12 adults with audiometric thresholds <15 dBHL (24 ears and mean age of 27 years. The parameters used for the recording with both stimuli in intensities of 80, 60, 40, 20 dBnHL were alternate polarity and repetition rate of 27.1 Hz. RESULTS: The CE-chirp® latencies for wave V were longer than click latencies at low intensity levels (20 and 40 dBnHL. At high intensity levels (60 and 80 dBnHL, the opposite occurred. Larger wave V amplitudes were observed with CE-chirp® in all intensity levels, except at 80 dBnHL. CONCLUSION: The CE-chirp® showed shorter latencies than those observed with clicks at high intensity levels and larger amplitudes at all intensity levels, except at 80 dBnHL. The waves I and III tended to disappear with CE-chirp® stimulation.

  9. Synthesis and Characterization of Multiwalled Carbon Nanotubes/Poly(HEMA-co-MMA) by Utilizing Click Chemistry.

    Science.gov (United States)

    Bach, Long Giang; Cao, Xuan Thang; Islam, Md Rafiqul; Jeong, Yeon Tae; Kim, Jong Su; Lim, Kwon Taek

    2016-03-01

    The hybrid material consisting of multi walled carbon nanotubes (MWNTs) and poly(2-hydroxyethylmethacrylate-co-methylmethacrylate) [poly(HEMA-co-MMA)] was synthesized by a combination of RAFT and Click chemistry. In the primary stage, the copolymer poly(HEMA-co-MMA) was prepared by applying RAFT technique. Alkynyl side groups were incorporated onto the poly(HEMA-co-MMA) backbone by esterification reaction. Then, MWNTs-N3 was prepared by treating MWNTs with 4-azidobutylamine. The click coupling reaction between azide-functionalized MWNTs (MWNTs-N3) and the alkyne-functionalized random copolymer ((HEMA-co-MMA)-Alkyne) with the Cu(I)-catalyzed [3+2] Huisgen cycloaddition afforded the hybrid compound. The structure and properties of poly(MMA-co-HEMA)-g-MWNTs were investigated by FT-IR, EDX and TGA measurements. The copolymer brushes were observed to be immobilized onto the functionalized MWNTs by SEM and TEM analysis.

  10. Interactive Sea Level Rise App & Online Viewer Offers Deep Dive Into Climate

    Science.gov (United States)

    Turrin, M.; Porter, D. F.; Ryan, W. B. F.; Pfirman, S. L.

    2015-12-01

    Climate has captured the attention of the public but its complexity can cause interested individuals to turn to opinion pieces, news articles or blogs for information. These platforms often oversimplify or present heavily interpreted or personalized perspectives. Data interactives are an extremely effective way to explore complex geoscience topics like climate, opening windows of understanding for the user that have previously been closed. Layering data onto maps through programs like GeoMapApp and the Earth Observer App has allowed users to dig directly into science data, but with only limited scaffolding. The interactive 'Polar Explorer: Sea Level Explorer App' provides a richly layered introduction to a range of topics connected to sea level rise. Each map is supported with a pop up and a short audio file of supplementary material, and an information page that includes the data source and links for further reading. This type of learning platform works well for both the formal and informal learning environment. Through science data displayed as map visualizations the user is invited into topics through an introductory question, such as "Why does sea level change?" After clicking on that question the user moves to a second layer of questions exploring the role of the ocean, the atmosphere, the contribution from the world's glaciers, world's ice sheets and other less obvious considerations such as the role of post-glacial rebound, or the mining of groundwater. Each question ends in a data map, or series of maps, that offer opportunities to interact with the topic. Under the role of the ocean 'Internal Ocean Temperature' offers the user a chance to touch to see temperature values spatially over the world's ocean, or to click through a data series starting at the ocean surface and diving to 5000 meters of depth showing how temperature changes with depth. Other sections, like the role of deglaciation of North America, allow the user to click and see change through

  11. Construct validity and inter-rater reliability of the Dutch activity measure for post-acute care "6-clicks" basic mobility form to assess the mobility of hospitalized patients.

    Science.gov (United States)

    Geelen, Sven Jacobus Gertruda; Valkenet, Karin; Veenhof, Cindy

    2018-05-12

    To evaluate the construct validity and the inter-rater reliability of the Dutch Activity Measure for Post-Acute Care "6-clicks" Basic Mobility short form measuring the patient's mobility in Dutch hospital care. First, the "6-clicks" was translated by using a forward-backward translation protocol. Next, 64 patients were assessed by the physiotherapist to determine the validity while being admitted to the Internal Medicine wards of a university medical center. Six hypotheses were tested regarding the construct "mobility" which showed that: Better "6-clicks" scores were related to less restrictive pre-admission living situations (p = 0.011), less restrictive discharge locations (p = 0.001), more independence in activities of daily living (p = 0.001) and less physiotherapy visits (p Dutch "6-clicks" shows a good construct validity and moderate-to-excellent inter-rater reliability when used to assess the mobility of hospitalized patients. Implications for Rehabilitation Even though various measurement tools have been developed, it appears the majority of physiotherapists working in a hospital currently do not use these tools as a standard part of their care. The Activity Measure for Post-Acute Care "6-clicks" Basic Mobility is the only tool which is designed to be short, easy to use within usual care and has been validated in the entire hospital population. This study shows that the Dutch version of the Activity Measure for Post-Acute Care "6-clicks" Basic Mobility form is a valid, easy to use, quick tool to assess the basic mobility of Dutch hospitalized patients.

  12. Synthesis of two new alkyne-bearing linkers used for the preparation of siRNA for labeling by click chemistry with fluorine-18

    International Nuclear Information System (INIS)

    Flagothier, Jessica; Kaisin, Geoffroy; Mercier, Frederic; Thonon, David; Teller, Nathalie; Wouters, Johan; Luxen, André

    2012-01-01

    Oligonucleotides (ONs) and more particularly siRNAs are promising drugs but their pharmacokinetics and biodistribution are widely unknown. Positron Emission Tomography (PET) using fluorine-18 is a suitable technique to quantify these biological processes. Click chemistry (Huisgen cycloaddition) is the current method for labeling siRNA. In order to study the influence of a linker bearing by [ 18 F] labeled ONs, on the in vivo pharmacokinetic and metabolism, we have developed two modified ONs by two new linkers. Here we report the synthesis of two alkyne-bearing linkers, the incorporation onto a ONs and the conjugation by click chemistry with a [ 18 F] prosthetic group. - Highlights: ► Synthesis of two new alkyne linkers. ► Functionalization at the 3′-end siRNA by alkyne linker derived of proline. ► Click chemistry between alkyne modified siRNA and [ 18 F] prosthetic group.

  13. Cytocompatible in situ forming chitosan/hyaluronan hydrogels via a metal-free click chemistry for soft tissue engineering.

    Science.gov (United States)

    Fan, Ming; Ma, Ye; Mao, Jiahui; Zhang, Ziwei; Tan, Huaping

    2015-07-01

    Injectable hydrogels are important cell scaffolding materials for tissue engineering and regenerative medicine. Here, we report a new class of biocompatible and biodegradable polysaccharide hydrogels derived from chitosan and hyaluronan via a metal-free click chemistry, without the addition of copper catalyst. For the metal-free click reaction, chitosan and hyaluronan were modified with oxanorbornadiene (OB) and 11-azido-3,6,9-trioxaundecan-1-amine (AA), respectively. The gelation is attributed to the triazole ring formation between OB and azido groups of polysaccharide derivatives. The molecular structures were verified by FT-IR spectroscopy and elemental analysis, giving substitution degrees of 58% and 47% for chitosan-OB and hyaluronan-AA, respectively. The in vitro gelation, morphologies, equilibrium swelling, compressive modulus and degradation of the composite hydrogels were examined. The potential of the metal-free hydrogel as a cell scaffold was demonstrated by encapsulation of human adipose-derived stem cells (ASCs) within the gel matrix in vitro. Cell culture showed that this metal-free hydrogel could support survival and proliferation of ASCs. A preliminary in vivo study demonstrated the usefulness of the hydrogel as an injectable scaffold for adipose tissue engineering. These characteristics provide a potential opportunity to use the metal-free click chemistry in preparation of biocompatible hydrogels for soft tissue engineering applications. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. Global Sourcing, Technology, and Factor Intensity: Firm-level Relationships

    OpenAIRE

    TOMIURA Eiichi

    2007-01-01

    This paper empirically examines how technology and capital intensity are related with the firm's global sourcing decision. Firm-level data are derived from a survey covering all manufacturing industries in Japan without any firm-size threshold. Firms are disaggregated by their make-or-buy decision (in-house or outsourcing) and by their choice of sourcing location (offshore or domestic). Capital-intensive or R&D-intensive firms tend to source in-house from their FDI affiliates rather than outs...

  15. Versatile post-functionalization of the external shell of cowpea chlorotic mottle virus by using click chemistry

    NARCIS (Netherlands)

    Hommersom, C.A.; Matt, B.D.; van der Ham, A.M.; Cornelissen, Jeroen Johannes Lambertus Maria; Katsonis, Nathalie Hélène

    2014-01-01

    We present the modification of the outer protein shell of cowpea chlorotic mottle virus (CCMV) with linear and strained alkyne groups. These functionalized protein capsids constitute valuable platforms for post-functionalization via click chemistry. After modification, the integrity of the capsid

  16. Click-coated, heparinized, decellularized vascular grafts.

    Science.gov (United States)

    Dimitrievska, Sashka; Cai, Chao; Weyers, Amanda; Balestrini, Jenna L; Lin, Tylee; Sundaram, Sumati; Hatachi, Go; Spiegel, David A; Kyriakides, Themis R; Miao, Jianjun; Li, Guoyun; Niklason, Laura E; Linhardt, Robert J

    2015-02-01

    A novel method enabling the engineering of a dense and appropriately oriented heparin-containing layer on decellularized aortas has been developed. Amino groups of decellularized aortas were first modified to azido groups using 3-azidobenzoic acid. Azide-clickable dendrons were attached onto the azido groups through "alkyne-azide" click chemistry, affording a tenfold amplification of adhesions sites. Dendron end groups were finally decorated with end-on modified heparin chains. Heparin chains were oriented like heparan sulfate groups on native endothelial cells surface. X-ray photoelectron spectroscopy, nuclear magnetic resonance imaging, mass spectrometry and Fourier transform infrared FTIR spectroscopy were used to characterize the synthesis steps, building the final heparin layered coatings. The continuity of the heparin coating was verified using fluorescent microscopy and histological analysis. The efficacy of heparin linkage was demonstrated with factor Xa anti-thrombogenic assay and platelet adhesion studies. The results suggest that oriented heparin immobilization to decellularized aortas may improve the in vivo blood compatibility of decellularized aortas and vessels. Copyright © 2014 Acta Materialia Inc. All rights reserved.

  17. Background information on sources of low-level radionuclide emissions to air

    International Nuclear Information System (INIS)

    Corbit, C.D.; Herrington, W.N.; Higby, D.P.; Stout, L.A.; Corley, J.P.

    1983-09-01

    This report provides a general description and reported emissions for eight low-level radioactive source categories, including facilties that are licensed by the Nuclear Regulatory Commission (NRC) and Agreement States, and non-Department of Energy (DOE) federal facilities. The eight categories of low-level radioactive source facilities covered by this report are: research and test reactors, accelerators, the radiopharmaceutical industry, source manufacturers, medical facilities, laboratories, naval shipyards, and low-level commercial waste disposal sites. Under each category five elements are addressed: a general description, a facility and process description, the emission control systems, a site description, and the radionuclides released to air (from routine operations)

  18. Background information on sources of low-level radionuclide emissions to air

    Energy Technology Data Exchange (ETDEWEB)

    Corbit, C.D.; Herrington, W.N.; Higby, D.P.; Stout, L.A.; Corley, J.P.

    1983-09-01

    This report provides a general description and reported emissions for eight low-level radioactive source categories, including facilties that are licensed by the Nuclear Regulatory Commission (NRC) and Agreement States, and non-Department of Energy (DOE) federal facilities. The eight categories of low-level radioactive source facilities covered by this report are: research and test reactors, accelerators, the radiopharmaceutical industry, source manufacturers, medical facilities, laboratories, naval shipyards, and low-level commercial waste disposal sites. Under each category five elements are addressed: a general description, a facility and process description, the emission control systems, a site description, and the radionuclides released to air (from routine operations).

  19. System level modelling with open source tools

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Koefoed; Madsen, Jan; Niaki, Seyed Hosein Attarzadeh

    , called ForSyDe. ForSyDe is available under the open Source approach, which allows small and medium enterprises (SME) to get easy access to advanced modeling capabilities and tools. We give an introduction to the design methodology through the system level modeling of a simple industrial use case, and we...

  20. Garage carbon monoxide levels from sources commonly used in intentional poisoning.

    Science.gov (United States)

    Hampson, Neil B; Holm, James R; Courtney, Todd G

    2017-01-01

    The incidence of intentional carbon monoxide (CO) poisoning is believed to have declined due to strict federal CO emissions standards for motor vehicles and the uniform application of catalytic converters (CC). We sought to compare ambient CO levels produced by automobiles with and without catalytic converters in a residential garage, as well as from other CO sources commonly used for intentional poisoning. CO levels were measured inside a freestanding 73 m3 one-car garage. CO sources included a 1971 automobile without CC, 2003 automobile with CC, charcoal grill, electrical generator, lawn mower and leaf blower. After 20 minutes of operation, the CO level in the garage was 253 PPM for the car without a catalytic converter and 30 PPM for the car equipped withone. CO levels after operating or burning the other sources were: charcoal 200 PPM; generator >999 PPM; lawn mower 198 PPM; and leaf blower 580 PPM. While emissions controls on automobiles have reduced intentional CO poisonings, alternate sources may produce CO at levels of the same magnitude as vehicles manufactured prior to the use of catalytic converters. Those involved in the care of potentially suicidal individuals should be aware of this.

  1. Estimation of low-level neutron dose-equivalent rate by using extrapolation method for a curie level Am–Be neutron source

    International Nuclear Information System (INIS)

    Li, Gang; Xu, Jiayun; Zhang, Jie

    2015-01-01

    Neutron radiation protection is an important research area because of the strong radiation biological effect of neutron field. The radiation dose of neutron is closely related to the neutron energy, and the connected relationship is a complex function of energy. For the low-level neutron radiation field (e.g. the Am–Be source), the commonly used commercial neutron dosimeter cannot always reflect the low-level dose rate, which is restricted by its own sensitivity limit and measuring range. In this paper, the intensity distribution of neutron field caused by a curie level Am–Be neutron source was investigated by measuring the count rates obtained through a 3 He proportional counter at different locations around the source. The results indicate that the count rates outside of the source room are negligible compared with the count rates measured in the source room. In the source room, 3 He proportional counter and neutron dosimeter were used to measure the count rates and dose rates respectively at different distances to the source. The results indicate that both the count rates and dose rates decrease exponentially with the increasing distance, and the dose rates measured by a commercial dosimeter are in good agreement with the results calculated by the Geant4 simulation within the inherent errors recommended by ICRP and IEC. Further studies presented in this paper indicate that the low-level neutron dose equivalent rates in the source room increase exponentially with the increasing low-energy neutron count rates when the source is lifted from the shield with different radiation intensities. Based on this relationship as well as the count rates measured at larger distance to the source, the dose rates can be calculated approximately by the extrapolation method. This principle can be used to estimate the low level neutron dose values in the source room which cannot be measured directly by a commercial dosimeter. - Highlights: • The scope of the affected area for

  2. Meta-analysis on Methane Mitigating Properties of Saponin-rich Sources in the Rumen: Influence of Addition Levels and Plant Sources

    Directory of Open Access Journals (Sweden)

    Anuraga Jayanegara

    2014-10-01

    Full Text Available Saponins have been considered as promising natural substances for mitigating methane emissions from ruminants. However, studies reported that addition of saponin-rich sources often arrived at contrasting results, i.e. either it decreased methane or it did not. The aim of the present study was to assess ruminal methane emissions through a meta-analytical approach of integrating related studies from published papers which described various levels of different saponin-rich sources being added to ruminant feed. A database was constructed from published literature reporting the addition of saponin-rich sources at various levels and then monitoring ruminal methane emissions in vitro. Accordingly, levels of saponin-rich source additions as well as different saponin sources were specified in the database. Apart from methane, other related rumen fermentation parameters were also included in the database, i.e. organic matter digestibility, gas production, pH, ammonia concentration, short-chain fatty acid profiles and protozoal count. A total of 23 studies comprised of 89 data points met the inclusion criteria. The data obtained were subsequently subjected to a statistical meta-analysis based on mixed model methodology. Accordingly, different studies were treated as random effects whereas levels of saponin-rich source additions or different saponin sources were considered as fixed effects. Model statistics used were p-value and root mean square error. Results showed that an addition of increasing levels of a saponin-rich source decreased methane emission per unit of substrate incubated as well as per unit of total gas produced (ptea>quillaja, statistically they did not differ each other. It can be concluded that methane mitigating properties of saponins in the rumen are level- and source-dependent.

  3. Surface Modification of Nanoporous 1,2-Polybutadiene by Atom Transfer Radical Polymerization or Click Chemistry

    DEFF Research Database (Denmark)

    Guo, Fengxiao; Jankova Atanasova, Katja; Schulte, Lars

    2010-01-01

    ATRP-grafting of hydrophilic polyacrylates and click of MPEG, the originally hydrophobic samples transformed into hydrophilic nanoporous materials. The successful modification was confirmed by infrared spectroscopy, contact angle measurements and measurements of spontaneous water uptake, while...... the morphology was investigated by small-angle X-ray scattering and transmission electron microscopy....

  4. "+CLICK": pilot of a web-based training program to enhance ART adherence among HIV-positive youth.

    Science.gov (United States)

    Shegog, Ross; Markham, Christine M; Leonard, Amy D; Bui, Thanh C; Paul, Mary E

    2012-01-01

    Youth account for almost half of all new HIV infections in the United States. Adherence to antiretroviral treatment (ART) is critical for successful management, yet reported adherence rates for youth are often low. This study pilot-tested "+CLICK," an innovative, web-based, adherence intervention for HIV-positive youth as an adjunct to traditional clinic-based, self-management education. The theory-based application, developed for HIV-infected youth, 13-24 years of age, provides tailored activities addressing attitudes, knowledge, skills, and self-efficacy related to ART adherence. HIV-positive youth (N=10) pilot-tested "+CLICK" to assess usability (ease of use, credibility, understandability, acceptability, motivation) and short-term psychosocial outcomes (importance and self-efficacy related to ART adherence) using a single-group, pre-/post-test study design in a hospital-based pediatric clinic (n=8) and home (n=2) location. Youth were mostly female (80%) and Black (80%). Mean age was 17.8 years (SD=2.65, range 14-22). All were infected perinatally and had been living with HIV all their lives. Most learned their HIV status by age 10 years. Sixty percent reported an undetectable viral load, whilst 10% reported a viral load of over 50,000. Half (50%) reported a normal CD4 count, whilst 20% reported having low CD4 (90%). Most (70%) indicated they would use "+CLICK" again. Short-term psychosocial outcomes indicate significant increase in medication adherence self-efficacy (pART adherence. Further research on long-term and behavioral effects is indicated prior to broader dissemination into clinical practice.

  5. Characterisation of a protection level Am-241 calibration source

    Science.gov (United States)

    Bass, G. A.; Rossiter, M. J.; Williams, T. T.

    1992-11-01

    The various measurements involved in the commissioning process of an Am-241 radioactive source and transport mechanisms to be used for protection level calibration work are detailed. The source and its handling mechanisms are described and measurements to characterize the resultant gamma ray beam are described. For the beam measurements, the inverse square law is investigated and beam uniformity is assessed. A trial calibration of ionization chambers is described. The Am-241 irradiation facility is concluded to be suitable for calibrating secondary standards as part of the calibration service offered for protection level instruments. The umbra part of beam is acceptably uniform for a range of chambers and the measurements obtained were predictable and consistent. This quality will be added to the range of qualities offered as part of the protection level secondary standard calibration service.

  6. Alkyne- and 1,6-elimination- succinimidyl carbonate - terminated heterobifunctional poly(ethylene glycol) for reversible "Click" PEGylation.

    Science.gov (United States)

    Xie, Yumei; Duan, Shaofeng; Forrest, M Laird

    2010-01-01

    A new heterobifunctional (succinimidyl carbonate, SC)-activated poly(ethylene glycol) (PEG) with a reversible 1,6-elimination linker and a terminal alkyne for "click" chemistry was synthesized with high efficiency and low polydispersity. The α-alkyne-ω-hydroxyl PEG was first prepared using trimethylsilyl-2-propargyl alcohol as an initiator for ring-opening polymerization of ethylene oxide followed by mild deprotection with tetrabutylammonium fluoride. The hydroxy end was then modified with diglycolic anhydride to generate α-alkyne-ω-carboxylic acid PEG. The reversible 1, 6-elimination linker was introduced by conjugation of a hydroxymethyl phenol followed by activation with N,N'-disuccinimidyl carbonate to generate the heterobifunctional α-alkyne-ω-SC PEG. The terminal alkyne is available for "click" conjugation to azido ligands via 1,3-dipolar cycloaddition, and the succinimidyl carbonate will form a reversible conjugate to amines (e.g. in proteins) that can release the unaltered amine after base or enzyme catalyzed cleavage of the 1,6-linker.

  7. Production of unnaturally linked chimeric proteins using a combination of sortase-catalyzed transpeptidation and click chemistry.

    Science.gov (United States)

    Witte, Martin D; Theile, Christopher S; Wu, Tongfei; Guimaraes, Carla P; Blom, Annet E M; Ploegh, Hidde L

    2013-09-01

    Chimeric proteins, including bispecific antibodies, are biological tools with therapeutic applications. Genetic fusion and ligation methods allow the creation of N-to-C and C-to-N fused recombinant proteins, but not unnaturally linked N-to-N and C-to-C fusion proteins. This protocol describes a simple procedure for the production of such chimeric proteins, starting from correctly folded proteins and readily available peptides. By equipping the N terminus or C terminus of the proteins of interest with a set of click handles using sortase A, followed by a strain-promoted click reaction, unnatural N-to-N and C-to-C linked (hetero) fusion proteins are established. Examples of proteins that have been conjugated via this method include interleukin-2, interferon-α, ubiquitin, antibodies and several single-domain antibodies. If the peptides, sortase A and the proteins of interest are in hand, the unnaturally N-to-N and C-to-C fused proteins can be obtained in 3-4 d.

  8. Cyclodextrin-Triazole Derivative Functionalized on Ag-SiO{sub 2} Core-Shell Nanoparticles via Click Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gun Bae; Singu, Bal Sydulu; Hong, Sang Eun; Yoon, Kuk Ro [Hannam Univ., Daejeon (Korea, Republic of)

    2016-09-15

    Click chemistry has provided a versatile strategy for functionalization in solution chemistry under mild reaction conditions with a high degree of functional group compatibility. Initially, silver (Ag) nanoparticles were prepared by the chemical reduction method, followed by the synthesis of silver–silica (Ag–SiO{sub 2}) core–shell nanoparticles by the Stöber method. The Ag–SiO2 core shell nanoparticles were functionalized with the alkyne derivative. The cycloaddition reaction between the azide-functionalized cyclodextrin and the alkyne-functionalized Ag–SiO{sub 2} core–shell nanoparticles was carried out via the copper-catalyzed click reaction, leading to the formation of the cyclodextrin-triazole derivative on the Ag–SiO{sub 2} core–shell nanoparticles. The presence of the resulting cyclodextrin-triazole derivative on the silver–silica core–shell nanoparticles was confirmed by Fourier transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA).

  9. An interpenetrating HA/G/CS biomimic hydrogel via Diels-Alder click chemistry for cartilage tissue engineering.

    Science.gov (United States)

    Yu, Feng; Cao, Xiaodong; Zeng, Lei; Zhang, Qing; Chen, Xiaofeng

    2013-08-14

    In order to mimic the natural cartilage extracellular matrix, a novel biological degradable interpenetrating network hydrogel was synthesized from the gelatin (G), hyaluronic acid (HA) and chondroitin sulfate (CS) by Diels-Alder "click" chemistry. HA was modified with furylamine and G was modified with furancarboxylic acid respectively. (1)H NMR spectra and elemental analysis showed that the substitution degrees of HA-furan and G-furan were 71.5% and 44.5%. Then the hydrogels were finally synthesized by cross-linking furan-modified HA and G derivatives with dimaleimide poly(ethylene glycol) (MAL-PEG-MAL). The mechanical and degradation properties of the hydrogels could be tuned simply through varying the molar ratio between furan and maleimide. Rheological, mechanical and degradation studies demonstrated that the Diels-Alder "click" chemistry is an efficient method for preparing high performance biological interpenetrating hydrogels. This biomimic hydrogel with improved mechanical properties could have great potential applications in cartilage tissue engineering. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Freedom of Contract in Click Wrap Agreements in Malaysia and the United States of America

    Directory of Open Access Journals (Sweden)

    Maryam Rafiei

    2011-06-01

    Full Text Available Technological advancement in the communications industry, particularly over the last decade, has given rise to consumers and commercial providers who want to form their own business or contractual agreements via the Internet. The mark of such technology can be seen in a new form of contract called “click wrap.”

  11. Synthesis of [64Cu]DOTA-ADIBON3-Ala-PEG28-A20FMDV2 via copper-free click chemistry for PET imaging of integrin αvβ6

    International Nuclear Information System (INIS)

    Drishty Satpati; Nadine Bauer; Hausner, S.H.

    2014-01-01

    Catalyst-free click reactions are effective chemical tools for synthesis of radiometal-based radiopharmaceuticals offering advantages towards preparation of non-toxic agents with high specific activity. In the present study the radiotracer [ 64 Cu]DOTA-ADIBON 3 -Ala-PEG 28 -A20FMDV2, [ 64 Cu]3, was synthesized for positron emission tomography imaging of integrin α v β 6 expressing tumors via a strain-promoted click reaction using both a 'pre-click' and 'post-click' approaches. The radiotracer, prepared in >99 % radiochemical yield, was evaluated in vitro (64.6 ± 2.8 % binding to α v β 6 -positive cells vs. v β 6 -negative cells) and in vivo (α v β 6 -positive tumor uptake: 1.52 ± 0.16 % ID/g, 24 h p.i.). While the high initial renal uptake (76.2 ± 10.7 % ID/g at 1 h p.i.) was comparable to a previously reported radiotracer, [ 64 Cu]DOTA-PEG 28 -A20FMDV2, [ 64 Cu]3 showed notably improved renal clearance (11.3 ± 2.5 % ID/g at 24 h p.i.). Thus, the introduction of a chelator-strained alkyne system resulted in improved pharmacokinetics for the present radiotracer, highlighting the attractive prospects of strain-promoted click-based preparations in the construction of radiometalated bioconjugates for targeted molecular imaging and therapy. (author)

  12. Improving Kinetics of “Click-Crosslinking” for Self-Healing Nanocomposites by Graphene-Supported Cu-Nanoparticles

    Directory of Open Access Journals (Sweden)

    Neda Kargarfard

    2017-12-01

    Full Text Available Investigation of the curing kinetics of crosslinking reactions and the development of optimized catalyst systems is of importance for the preparation of self-healing nanocomposites, able to significantly extend their service lifetimes. Here we study different modified low molecular weight multivalent azides for a capsule-based self-healing approach, where self-healing is mediated by graphene-supported copper-nanoparticles, able to trigger “click”-based crosslinking of trivalent azides and alkynes. When monitoring the reaction kinetics of the curing reaction via reactive dynamic scanning calorimetry (DSC, it was found that the “click-crosslinking” reactivity decreased with increasing chain length of the according azide. Additionally, we could show a remarkable “click” reactivity already at 0 °C, highlighting the potential of click-based self-healing approaches. Furthermore, we varied the reaction temperature during the preparation of our tailor-made graphene-based copper(I catalyst to further optimize its catalytic activity. With the most active catalyst prepared at 700 °C and the optimized set-up of reactants on hand, we prepared capsule-based self-healing epoxy nanocomposites.

  13. Knee-clicks and visual traits indicate fighting ability in eland antelopes: multiple messages and back-up signals

    Directory of Open Access Journals (Sweden)

    Dabelsteen Torben

    2008-11-01

    Full Text Available Abstract Background Given the costs of signalling, why do males often advertise their fighting ability to rivals using several signals rather than just one? Multiple signalling theories have developed largely in studies of sexual signals, and less is known about their applicability to intra-sexual communication. We here investigate the evolutionary basis for the intricate agonistic signalling system in eland antelopes, paying particular attention to the evolutionary phenomenon of loud knee-clicking. Results A principal components analysis separated seven male traits into three groups. The dominant frequency of the knee-clicking sound honestly indicated body size, a main determinant of fighting ability. In contrast, the dewlap size increased with estimated age rather than body size, suggesting that, by magnifying the silhouette of older bulls disproportionately, the dewlap acts as an indicator of age-related traits such as fighting experience. Facemask darkness, frontal hairbrush size and body greyness aligned with a third underlying variable, presumed to be androgen-related aggression. A longitudinal study provided independent support of these findings. Conclusion The results show that the multiple agonistic signals in eland reflect three separate components of fighting ability: (1 body size, (2 age and (3 presumably androgen-related aggression, which is reflected in three backup signals. The study highlights how complex agonistic signalling systems can evolve through the simultaneous action of several selective forces, each of which favours multiple signals. Specifically, loud knee-clicking is discovered to be an honest signal of body size, providing an exceptional example of the potential for non-vocal acoustic communication in mammals.

  14. Study of the Effect of Grafting Method on Surface Polarity of Tempo-Oxidized Nanocellulose Using Polycaprolactone as the Modifying Compound: Esterification versus Click-Chemistry

    Directory of Open Access Journals (Sweden)

    Abdelhaq Benkaddour

    2013-12-01

    Full Text Available Esterification and click-chemistry were evaluated as surface modification treatments for TEMPO-oxidized nanocelluloses (TONC using Polycaprolactone-diol (PCL as modifying compound in order to improve the dispersion of nanofibers in organic media. These two grafting strategies were analyzed and compared. The first consists of grafting directly the PCL onto TONC, and was carried out by esterification between hydroxyl groups of PCL and carboxyl groups of TONC. The second strategy known as click-chemistry is based on the 1,3-dipolar cycloaddition reaction between azides and alkyne terminated moieties to form the triazole ring between PCL and TONC. The grafted samples were characterized by transmission electron microscopy (TEM, Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, and Thermogravimetry analysis (TGA. Further, the effects of the two treatments on the surface hydrophobization of TONC were investigated by contact angle measurements. The results show that both methods confirm the success of such a modification and the click reaction was significantly more effective than esterification.

  15. Levels and source apportionment of children's lead exposure: Could urinary lead be used to identify the levels and sources of children's lead pollution?

    International Nuclear Information System (INIS)

    Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

    2015-01-01

    As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as 207 Pb/ 206 Pb, 208 Pb/ 206 Pb and 204 Pb/ 206 Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. - Highlights: • Pb isotopes of environmental media and children's blood and urine were analyzed. • Pb exposure and pollution source were studied in lead-acid battery and coking areas. • Pb isotope ratios in blood and urine were similar to those of food, water and PM. • Urine Pb level may not be used as a proxy for indicating the lead levels in blood. • Urine Pb isotope ratios is an alternative to identify source and exposure pathways. - Urinary lead is not a preferable proxy to estimate blood lead level, but urinary lead isotope ratios could be an alternative for identifying the sources of lead exposure in children

  16. Brainstem auditory evoked potentials with the use of acoustic clicks and complex verbal sounds in young adults with learning disabilities.

    Science.gov (United States)

    Kouni, Sophia N; Giannopoulos, Sotirios; Ziavra, Nausika; Koutsojannis, Constantinos

    2013-01-01

    Acoustic signals are transmitted through the external and middle ear mechanically to the cochlea where they are transduced into electrical impulse for further transmission via the auditory nerve. The auditory nerve encodes the acoustic sounds that are conveyed to the auditory brainstem. Multiple brainstem nuclei, the cochlea, the midbrain, the thalamus, and the cortex constitute the central auditory system. In clinical practice, auditory brainstem responses (ABRs) to simple stimuli such as click or tones are widely used. Recently, complex stimuli or complex auditory brain responses (cABRs), such as monosyllabic speech stimuli and music, are being used as a tool to study the brainstem processing of speech sounds. We have used the classic 'click' as well as, for the first time, the artificial successive complex stimuli 'ba', which constitutes the Greek word 'baba' corresponding to the English 'daddy'. Twenty young adults institutionally diagnosed as dyslexic (10 subjects) or light dyslexic (10 subjects) comprised the diseased group. Twenty sex-, age-, education-, hearing sensitivity-, and IQ-matched normal subjects comprised the control group. Measurements included the absolute latencies of waves I through V, the interpeak latencies elicited by the classical acoustic click, the negative peak latencies of A and C waves, as well as the interpeak latencies of A-C elicited by the verbal stimulus 'baba' created on a digital speech synthesizer. The absolute peak latencies of waves I, III, and V in response to monoaural rarefaction clicks as well as the interpeak latencies I-III, III-V, and I-V in the dyslexic subjects, although increased in comparison with normal subjects, did not reach the level of a significant difference (pwave C and the interpeak latencies of A-C elicited by verbal stimuli were found to be increased in the dyslexic group in comparison with the control group (p=0.0004 and p=0.045, respectively). In the subgroup consisting of 10 patients suffering from

  17. Magnetic poly(N-propargylacrylamide) microspheres: preparation by precipitation polymerization and use in model click reactions

    Czech Academy of Sciences Publication Activity Database

    Macková, Hana; Proks, Vladimír; Horák, Daniel; Kučka, Jan; Trchová, Miroslava

    2011-01-01

    Roč. 49, č. 22 (2011), s. 4820-4829 ISSN 0887-624X R&D Projects: GA AV ČR KJB400500904; GA AV ČR(CZ) KAN401220801; GA ČR GAP503/10/0664 Institutional research plan: CEZ:AV0Z40500505 Keywords : click chemistry * magnetic * microspheres Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.919, year: 2011

  18. Synthesis of Donor-Acceptor Conjugated Polymers by "CLICK" Polymerization for OPV applications

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbæk; Yu, Donghong

    The intent of this study was to utilize the Copper(I)-catalyzed Azide Alkyne Cycloaddition (CuAAC) as a polymerization technique (“Click” Polymerization) for synthesizing novel π-conjugated low band gap polymers for organic photovoltaic applications (OPV). The chosen approach was to synthesize...... an alternating electron donating (donor, D) and electron withdrawing (acceptor, A) co-polymer. The chosen monomers were well known units, and the novelty lies in using the monomer units with the click methodology. An insoluble alternating copolymer consisting of 2,7-diazido-9,9-dioctyl-9Hflourene and 1...

  19. Hexachlorobenzene sources, levels and human exposure in the environment of China

    NARCIS (Netherlands)

    Wang, G.; Lu, Y.L.; Han, Jingyi; Luo, W.; Shi, Y.J.; Wang, T.Y.; Sun, Y.M.

    2010-01-01

    This article summarizes the published scientific data on sources, levels and human exposure of hexachlorobenzene (HCB) in China. Potential sources of unintended HCB emission were assessed by production information, emission factors and environmental policies. HCB was observed in various

  20. Catalyst-Free Conjugation and In Situ Quantification of Nanoparticle Ligand Surface Density Using Fluorogenic Cu-Free Click Chemistry

    DEFF Research Database (Denmark)

    Jølck, Rasmus Irming; Sun, Honghao; Berg, Rolf Henrik

    2011-01-01

    A highly efficient method for functionalizing nanoparticles and directly quantifying conjugation efficiency and ligand surface density has been developed. Attachment of 3-azido-modifed RGD-peptides to PEGylated liposomes was achieved by using Cu-free click conditions. Upon coupling a fluorophore ...

  1. Pulse width modulated buck-boost five-level current source inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Gao, F.; Loh, P.C.

    2008-01-01

    , resulting in the natural balance of input current. For maintaining the normalized volt-sec average unchanged, the alternative phase opposition disposition (APOD) modulation scheme with typical gating signal mapping technique from voltage source inverter (VSI) to CSI can be assumed to control the five......This paper presents new five-level current source inverters (CSIs) with voltage/current buck-boost capability. Being different from the existing multilevel CSI, the proposed CSIs were first designed to regulate the flowing path of dc input current by controlling two additional active switches......-level buck-boost CSIs. Next by observing the hidden current charging path during inductive charging interval under APOD modulation, it is noted that the buck-boost five-level CSI can then be further modified with lesser active component without degrading output performance. To verify the theoretical findings...

  2. Efficient Homodifunctional Bimolecular Ring-Closure Method for Cyclic Polymers by Combining RAFT and Self-Accelerating Click Reaction.

    Science.gov (United States)

    Qu, Lin; Sun, Peng; Wu, Ying; Zhang, Ke; Liu, Zhengping

    2017-08-01

    An efficient metal-free homodifunctional bimolecular ring-closure method is developed for the formation of cyclic polymers by combining reversible addition-fragmentation chain transfer (RAFT) polymerization and self-accelerating click reaction. In this approach, α,ω-homodifunctional linear polymers with azide terminals are prepared by RAFT polymerization and postmodification of polymer chain end groups. By virtue of sym-dibenzo-1,5-cyclooctadiene-3,7-diyne (DBA) as small linkers, well-defined cyclic polymers are then prepared using the self-accelerating double strain-promoted azide-alkyne click (DSPAAC) reaction to ring-close the azide end-functionalized homodifunctional linear polymer precursors. Due to the self-accelerating property of DSPAAC ring-closing reaction, this novel method eliminates the requirement of equimolar amounts of telechelic polymers and small linkers in traditional bimolecular ring-closure methods. It facilitates this method to efficiently and conveniently produce varied pure cyclic polymers by employing an excess molar amount of DBA small linkers. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Levels-of-processing effect on internal source monitoring in schizophrenia.

    Science.gov (United States)

    Ragland, J Daniel; McCarthy, Erin; Bilker, Warren B; Brensinger, Colleen M; Valdez, Jeffrey; Kohler, Christian; Gur, Raquel E; Gur, Ruben C

    2006-05-01

    Recognition can be normalized in schizophrenia by providing patients with semantic organizational strategies through a levels-of-processing (LOP) framework. However, patients may rely primarily on familiarity effects, making recognition less sensitive than source monitoring to the strength of the episodic memory trace. The current study investigates whether providing semantic organizational strategies can also normalize patients' internal source-monitoring performance. Sixteen clinically stable medicated patients with schizophrenia and 15 demographically matched healthy controls were asked to identify the source of remembered words following an LOP-encoding paradigm in which they alternated between processing words on a 'shallow' perceptual versus a 'deep' semantic level. A multinomial analysis provided orthogonal measures of item recognition and source discrimination, and bootstrapping generated variance to allow for parametric analyses. LOP and group effects were tested by contrasting recognition and source-monitoring parameters for words that had been encoded during deep versus shallow processing conditions. As in a previous study there were no group differences in LOP effects on recognition performance, with patients and controls benefiting equally from deep versus shallow processing. Although there were no group differences in internal source monitoring, only controls had significantly better performance for words processed during the deep encoding condition. Patient performance did not correlate with clinical symptoms or medication dose. Providing a deep processing semantic encoding strategy significantly improved patients' recognition performance only. The lack of a significant LOP effect on internal source monitoring in patients may reflect subtle problems in the relational binding of semantic information that are independent of strategic memory processes.

  4. Modulation Schemes of Multi-phase Three-Level Z-Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    different modulation requirement and output performance. For clearly illustrating the detailed modulation process, time domain analysis instead of the traditional multi-dimensional space vector demonstration is assumed which reveals the right way to insert shoot-through durations in the switching sequence...... with minimal commutation count. Lastly, the theoretical findings are verified in Matlab/PLECS simulation and experimentally using constructed laboratory prototypes.......This paper investigates the modulation schemes of three-level multiphase Z-source inverters with either two Z-source networks or single Z-source network connected between the dc sources and inverter circuitry. With the proper offset added for achieving both desired four-leg operation and optimized...

  5. STUDIES OF SHADING LEVELS AND NUTRITION SOURCES ON GROWTH, YIELD

    Directory of Open Access Journals (Sweden)

    Edi Purwanto

    2011-10-01

    Full Text Available Growth and biochemical content of medicinal crops are influenced by agroecosystems characteristics . The objective of this research was to determine the optimum shading level and type of fertilizer as sources of nutrition on the growth, yield, and andrographolide content of sambiloto. The experiment used Split Plot Design with basic design of Randomized Complete Block Design arranged with two treatment factors, with three replications. The first factor as the main plot was shading levels, namely without shading, 25% shading, 50% shading, and 75% shading. The second factor as the sub plot was sources of nutrition reprented by type of fertilizer, namely NPK fertilizer, cow stable fertilizer, and compost fertilizer. The result of research indicated that shading level and the kind of nutrition influenced some growth and yield variables such as number of leaves, number of branches, plant height, plant dry weight and simplisia weight, and andrographolide content. Interaction of shading level at 25% and straw compost fertilizer performed best in growth characteristics, while the highest andrographolide content resulted from the treatment combination of 50% shading level and straw compost fertilizer.

  6. Direct electrochemistry of horseradish peroxidase immobilized on electrografted 4-ethynylphenyl film via click chemistry

    International Nuclear Information System (INIS)

    Ran Qin; Peng Ru; Liang Cong; Ye Siqiu; Xian Yuezhong; Zhang Wenjing; Jin Litong

    2011-01-01

    Graphical abstract: Hydrogen peroxide biosensor was developed based on electrochemically assisted aryldiazonium salt chemistry and click chemistry. Highlights: → A simple, versatile two-step approach, which is based on electrochemically assisted aryldiazonium salt chemistry and Cu(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction has been developed for covalent redox proteins immobilization and biosensing for the first time. In this work, azido group modified HRP was covalently grafted on 4-ethylnylphenyl diazonium compound via CuAAC reaction and a novel electrochemical hydrogen peroxide biosensor was successfully fabricated. - Abstract: In this paper, a simple two-step approach for redox protein immobilization was introduced. Firstly, alkynyl-terminated film was formed on electrode surface by electrochemical reduction of 4-ethylnylphenyl (4-EP) diazonium compound. Then, horseradish peroxidase (HRP) modified with azido group was covalently immobilized onto the electrografted film via click reaction. Reflection absorption infrared (RAIR) spectroscopy and electrochemical methods were used to characterize the modification process. The results indicate that HRP retains its native structure and shows fast direct electron transfer. Moreover, the immobilized HRP shows excellent electrocatalytic reduction activity toward H 2 O 2 with a linear range of 5.0 x 10 -6 to 9.3 x 10 -4 mol L -1 .

  7. Direct electrochemistry of horseradish peroxidase immobilized on electrografted 4-ethynylphenyl film via click chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Ran Qin; Peng Ru; Liang Cong; Ye Siqiu [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Xian Yuezhong, E-mail: yzxian@chem.ecnu.edu.cn [Department of Chemistry, East China Normal University, Shanghai 200062 (China); Zhang Wenjing; Jin Litong [Department of Chemistry, East China Normal University, Shanghai 200062 (China)

    2011-07-04

    Graphical abstract: Hydrogen peroxide biosensor was developed based on electrochemically assisted aryldiazonium salt chemistry and click chemistry. Highlights: > A simple, versatile two-step approach, which is based on electrochemically assisted aryldiazonium salt chemistry and Cu(I)-catalyzed azide alkyne cycloaddition (CuAAC) reaction has been developed for covalent redox proteins immobilization and biosensing for the first time. In this work, azido group modified HRP was covalently grafted on 4-ethylnylphenyl diazonium compound via CuAAC reaction and a novel electrochemical hydrogen peroxide biosensor was successfully fabricated. - Abstract: In this paper, a simple two-step approach for redox protein immobilization was introduced. Firstly, alkynyl-terminated film was formed on electrode surface by electrochemical reduction of 4-ethylnylphenyl (4-EP) diazonium compound. Then, horseradish peroxidase (HRP) modified with azido group was covalently immobilized onto the electrografted film via click reaction. Reflection absorption infrared (RAIR) spectroscopy and electrochemical methods were used to characterize the modification process. The results indicate that HRP retains its native structure and shows fast direct electron transfer. Moreover, the immobilized HRP shows excellent electrocatalytic reduction activity toward H{sub 2}O{sub 2} with a linear range of 5.0 x 10{sup -6} to 9.3 x 10{sup -4} mol L{sup -1}.

  8. On doing two things at once: dolphin brain and nose coordinate sonar clicks, buzzes and emotional squeals with social sounds during fish capture.

    Science.gov (United States)

    Ridgway, Sam; Samuelson Dibble, Dianna; Van Alstyne, Kaitlin; Price, DruAnn

    2015-12-01

    Dolphins fishing alone in open waters may whistle without interrupting their sonar clicks as they find and eat or reject fish. Our study is the first to match sound and video from the dolphin with sound and video from near the fish. During search and capture of fish, free-swimming dolphins carried cameras to record video and sound. A hydrophone in the far field near the fish also recorded sound. From these two perspectives, we studied the time course of dolphin sound production during fish capture. Our observations identify the instant of fish capture. There are three consistent acoustic phases: sonar clicks locate the fish; about 0.4 s before capture, the dolphin clicks become more rapid to form a second phase, the terminal buzz; at or just before capture, the buzz turns to an emotional squeal (the victory squeal), which may last 0.2 to 20 s after capture. The squeals are pulse bursts that vary in duration, peak frequency and amplitude. The victory squeal may be a reflection of emotion triggered by brain dopamine release. It may also affect prey to ease capture and/or it may be a way to communicate the presence of food to other dolphins. Dolphins also use whistles as communication or social sounds. Whistling during sonar clicking suggests that dolphins may be adept at doing two things at once. We know that dolphin brain hemispheres may sleep independently. Our results suggest that the two dolphin brain hemispheres may also act independently in communication. © 2015. Published by The Company of Biologists Ltd.

  9. One-pot synthesis of Au@SiO2 catalysts: A click chemistry approach

    KAUST Repository

    Solovyeva, Vera A.

    2014-10-13

    Using the copper-catalyzed azide-alkyne cycloaddition "click" reaction, a library of triazole amphiphiles with a variety of functional polar "heads" and hydrophobic or superhydrophobic "tails" was synthesized. The amphiphiles were evaluated for their ability to stabilize small Au nanoparticles, and, at the same time, serve as templates for nanocasting porous SiO2. One of the Au@SiO2 materials thus prepared was found to be a highly active catalyst for the Au nanoparticle-catalyzed regioselective hydroamination of alkynes.

  10. One-pot synthesis of Au@SiO2 catalysts: A click chemistry approach

    KAUST Repository

    Solovyeva, Vera A.; Vu, Khanh B.; Merican, Zulkifli; Sougrat, Rachid; Rodionov, Valentin O.

    2014-01-01

    Using the copper-catalyzed azide-alkyne cycloaddition "click" reaction, a library of triazole amphiphiles with a variety of functional polar "heads" and hydrophobic or superhydrophobic "tails" was synthesized. The amphiphiles were evaluated for their ability to stabilize small Au nanoparticles, and, at the same time, serve as templates for nanocasting porous SiO2. One of the Au@SiO2 materials thus prepared was found to be a highly active catalyst for the Au nanoparticle-catalyzed regioselective hydroamination of alkynes.

  11. Sperm whale predator-prey interactions involve chasing and buzzing, but no acoustic stunning

    DEFF Research Database (Denmark)

    Fais, Andrea; Johnson, M.; Wilson, Maria

    2016-01-01

    The sperm whale carries a hypertrophied nose that generates powerful clicks for long-range echolocation. However, it remains a conundrum how this bizarrely shaped apex predator catches its prey. Several hypotheses have been advanced to propose both active and passive means to acquire prey......, including acoustic debilitation of prey with very powerful clicks. Here we test these hypotheses by using sound and movement recording tags in a fine-scale study of buzz sequences to relate the acoustic behaviour of sperm whales with changes in acceleration in their head region during prey capture attempts....... We show that in the terminal buzz phase, sperm whales reduce inter-click intervals and estimated source levels by 1-2 orders of magnitude. As a result, received levels at the prey are more than an order of magnitude below levels required for debilitation, precluding acoustic stunning to facilitate...

  12. Impact of intentionally introduced sources on indoor VOC levels

    Energy Technology Data Exchange (ETDEWEB)

    Davis, C.S. [BOVAR Environmental, Downsview, Ontario (Canada); Otson, R. [Health Canada, Ottawa, Ontario (Canada). Environmental Health Centre

    1997-12-31

    The concentrations of 33 target volatile organic compounds (VOC) were measured in outdoor air and in indoor air before and after the introduction of dry-cleaned clothes, and consumer products into two suburban homes. Emissions from the household products (air fresheners, furniture polishes, mothballs, and dry-cleaned clothes), showering, and two paints were analyzed to obtain source profiles. There were measurable increases in the 24 h average concentrations for 10 compounds in one house and 8 compounds in the second house after introduction of the sources. A contribution by showering to indoor VOC was not evident although the impact of the other sources and outdoor air could be discerned, based on results for the major constituents of source emissions. Also, contributions by paints, applied three to six weeks prior to the monitoring, to indoor VOC concentrations were evident. The pattern of concentrations indicated that sink effects need to be considered in explaining the indoor concentrations that result when sources are introduced into homes. Quantitative estimates of the relative contributions of the sources to indoor VOC levels were not feasible through the use of chemical mass balance since the number of tracer species detected (up to 6) and that could be used for source apportionment was similar to the number of sources to be apportioned (up to 7).

  13. Control and design of full-bridge three-level converter for renewable energy sources

    DEFF Research Database (Denmark)

    Yao, Zhilei; Xu, Jing; Guerrero, Josep M.

    2015-01-01

    Output voltage of renewable energy sources, such as fuel cell and PV cell, is often low and varies widely with load and environmental conditions. Therefore, the high step-up DC-DC converter is needed between renewable energy sources and the grid-connected inverter. However, voltage stress...... of rectifier diodes is high and filter is large in traditional voltage-source converters in a wide input-voltage range. In order to solve the aforementioned problems, a full-bridge (FB) three-level (TL) converter is proposed. It can operate at both two-level and three-level modes, so it is suitable for wide...

  14. Non-Catalyzed Click Reactions of ADIBO Derivatives with 5-Methyluridine Azides and Conformational Study of the Resulting Triazoles

    Czech Academy of Sciences Publication Activity Database

    Smyslová, P.; Popa, I.; Lyčka, A.; Tejral, Gracian; Havlač, J.

    2015-01-01

    Roč. 10, č. 2 (2015), e0144613 E-ISSN 1932-6203 R&D Projects: GA TA ČR(CZ) TE01020028 Institutional support: RVO:68378041 Keywords : copper-free click * alkyne cycloaddition * chemistry Subject RIV: CC - Organic Chemistry Impact factor: 3.057, year: 2015

  15. Synthesis and characterization of a novel double cross-linked hydrogel based on Diels-Alder click reaction and coordination bonding.

    Science.gov (United States)

    Li, Shubin; Wang, Lu; Yu, Xuemei; Wang, Chengli; Wang, Zhenyu

    2018-01-01

    Hydrogels, promising biological materials, need to have both strong mechanical properties and also inherent self-healing properties. In this work a double cross-linked network (DN) hydrogel was designed and prepared by combining a Diels-Alder click reaction and coordination effects. This DN hydrogel had good thermodynamic properties, anti-EDTA performance and self-healing properties. In addition, the mechanical properties, swelling properties and surface morphology of DN hydrogels can be controlled by adjusting the ratio of Fe 3+ -catechol. The adjustment of pH value can change the color, crosslinking mode and mechanical properties of the DN hydrogel. This smart hydrogel created from DA click chemistry and coordination effects has significance for guiding the design of new hydrogels with good mechanical properties, self-healing properties and controlled cross-link density. Copyright © 2017. Published by Elsevier B.V.

  16. Examination of Conservatism in Ground-level Source Release Assumption when Performing Consequence Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung-yeop; Lim, Ho-Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    One of these assumptions frequently assumed is the assumption of ground-level source release. The user manual of a consequence analysis software HotSpot is mentioning like below: 'If you cannot estimate or calculate the effective release height, the actual physical release height (height of the stack) or zero for ground-level release should be used. This will usually yield a conservative estimate, (i.e., larger radiation doses for all downwind receptors, etc).' This recommendation could be agreed in aspect of conservatism but quantitative examination of the effect of this assumption to the result of consequence analysis is necessary. The source terms of Fukushima Dai-ichi NPP accident have been estimated by several studies using inverse modeling and one of the biggest sources of the difference between the results of these studies was different effective source release height assumed by each studies. It supports the importance of the quantitative examination of the influence by release height. Sensitivity analysis of the effective release height of radioactive sources was performed and the influence to the total effective dose was quantitatively examined in this study. Above 20% difference is maintained even at longer distances, when we compare the dose between the result assuming ground-level release and the results assuming other effective plume height. It means that we cannot ignore the influence of ground-level source assumption to the latent cancer fatality estimations. In addition, the assumption of ground-level release fundamentally prevents detailed analysis including diffusion of plume from effective plume height to the ground even though the influence of it is relatively lower in longer distance. When we additionally consider the influence of surface roughness, situations could be more serious. The ground level dose could be highly over-estimated in short downwind distance at the NPP sites which have low surface roughness such as Barakah site in

  17. Basic experiment on scattering type level gauge using neutron source

    International Nuclear Information System (INIS)

    Kumazaki, Hiroshi; Fukuchi, Ryoichi; Horiguchi, Yasuhiro

    1984-01-01

    The level gauges using sealed radiation sources have been utilized for pulp and chemical industries, however, for those gauges, transmission type gamma sources are used, which require considerably large radioactivity, and it hinders the spread to medium and small enterprises. Recently, Cf-252 has become easily available, and various He-3 counters are on the market, consequently, the scattering type level gauges combining them have been examined. With the level gauges of this type, the judgement of level can be made sufficiently with the Cf-252 below 3.7 x 10 6 Bq, therefore, if the practical instruments are made, they seem to spread into medium and small enterprises because of the safety and the chief handling radiation being unnecessary. For the purpose of developing and manufacturing for trial this scattering type level gauge, the basic experiment was carried out to examine the effects of the change of salt content and the thickness of vessels and the effect of scattering materials. The possibility of the on-off operation as level gauges was also examined. The experimental method and the results are reported. The count considerably decreased with increasing salt content. Scattering materials worked effectively to increase the count. (Kako, I.)

  18. Low-level radioactive waste performance assessments: Source term modeling

    International Nuclear Information System (INIS)

    Icenhour, A.S.; Godbee, H.W.; Miller, L.F.

    1995-01-01

    Low-level radioactive wastes (LLW) generated by government and commercial operations need to be isolated from the environment for at least 300 to 500 yr. Most existing sites for the storage or disposal of LLW employ the shallow-land burial approach. However, the U.S. Department of Energy currently emphasizes the use of engineered systems (e.g., packaging, concrete and metal barriers, and water collection systems). Future commercial LLW disposal sites may include such systems to mitigate radionuclide transport through the biosphere. Performance assessments must be conducted for LUW disposal facilities. These studies include comprehensive evaluations of radionuclide migration from the waste package, through the vadose zone, and within the water table. Atmospheric transport mechanisms are also studied. Figure I illustrates the performance assessment process. Estimates of the release of radionuclides from the waste packages (i.e., source terms) are used for subsequent hydrogeologic calculations required by a performance assessment. Computer models are typically used to describe the complex interactions of water with LLW and to determine the transport of radionuclides. Several commonly used computer programs for evaluating source terms include GWSCREEN, BLT (Breach-Leach-Transport), DUST (Disposal Unit Source Term), BARRIER (Ref. 5), as well as SOURCE1 and SOURCE2 (which are used in this study). The SOURCE1 and SOURCE2 codes were prepared by Rogers and Associates Engineering Corporation for the Oak Ridge National Laboratory (ORNL). SOURCE1 is designed for tumulus-type facilities, and SOURCE2 is tailored for silo, well-in-silo, and trench-type disposal facilities. This paper focuses on the source term for ORNL disposal facilities, and it describes improved computational methods for determining radionuclide transport from waste packages

  19. SureClick® (Darbepoetin alfa) can improve perceived satisfaction and competence for anemia treatment and increase self-administration in non-dialyzed patients with chronic kidney disease.

    Science.gov (United States)

    Bonafont, Xavier; Romero, Ramón; Martínez, Isabel; del Pino, María D; Gil, José M; Aranda, Pedro; Roca, Ramón; Claverol, Joana; Cucala, Mercedes

    2013-01-01

    SureClick® is a prefilled pen for administration of darbepoetin alfa (DA) that is ready-to-use. We explored patient satisfaction with SureClick® compared with prefilled syringes (PFS). Multicenter, prospective, 6-months, observational study in non-dialyzed patients with chronic kidney disease (CKD) treated with DA in PFS who switched to SureClick® at baseline. Main outcomes were: change in Anemia Treatment Satisfaction Questionnaire (ATSQ-S), Perceived Competence for Anemia Scale (PCAS) and self-administration rate. We enrolled 132 patients with a mean(SD) age of 71.3 (14.6) years, 57.6% women. Mean(SD) ATSQ-S scores at baseline and final records were 25.5 (7.9) and 31.6 (4.9) (on a scale from 0 to 36 maximum satisfaction-, mean change: 6.2, 95%CI: 4.6-7.8, pscale from 1 to 7 maximum competence, pperceived competence in anemia management in non-dialyzed CKD patients, and could increase the self-administration rate, thereby reducing use of health resources.

  20. Towards enhancing click-draw based graphical passwords using multi-touch behaviours on smartphones

    DEFF Research Database (Denmark)

    Meng, Weizhi; Li, Wenjuan; Kwok, Lam For

    2017-01-01

    Graphical passwords (GPs) are recognised as one of the potential alternatives in addressing the limitations in conventional text-based password authentication. With the rapid development of mobile devices (i.e., the increase of computing power), GP-based systems have already been implemented...... and its impact on graphical password creation is an important topic in the literature. In this paper, our interest is to investigate the influence of multi-touch behaviours on users’ habit in creating graphical passwords, especially on click-draw based GPs (shortly CD-GPS) on mobile devices...

  1. Synthesis of click-reactive HPMA copolymers using RAFT polymerization for drug delivery applications

    DEFF Research Database (Denmark)

    Ebbesen, Morten F; Schaffert, D.H.; Crowley, Michael L

    2013-01-01

    This study describes a versatile strategy combining reversible addition fragmentation transfer (RAFT) polymerization and click chemistry to synthesize well-defined, reactive copolymers of N-(2-hydroxypropyl)methacrylamide (HPMA) for drug delivery applications. A novel azide containing monomer N-(3......-azidopropyl)methacrylamide (AzMA) was synthesized and copolymerized with HPMA using RAFT polymerization to provide p(HPMA-co-AzMA) copolymers with high control of molecular weight (∼10–54 kDa) and polydispersity (≤1.06). The utility of the side-chain azide functionality by Cu(I)-catalyzed azide...

  2. On the hidden curriculum of the mouse click: An anthropologically drama

    Directory of Open Access Journals (Sweden)

    Tobias Werler

    2008-11-01

    Full Text Available Any process of education is media based. But the advent of computer based media in the classroom caused a qualitative change. This new type of media serves as a bodily and cognitive extension of man. The aim of the article is to demonstrate educational consequences of these new anthropologically premises. The article discusses the structure and concept of digital communication culture as it denies the existence of spatial distance. The click option of the mouse will be framed as digital communications hidden curriculum. In order to navigate in the digital world of education the texts concludes with that man has to develop sign-literacy to be able to master the iconic turn in education.

  3. A formal guidance for handling different uncertainty sources employed in the level 2 PSA

    International Nuclear Information System (INIS)

    Ahn, Kwang Il; Yang, Joon Eon; Ha, Jae Joo

    2004-01-01

    The methodological framework of the level 2 PSA appears to be currently standardized in a formalized fashion, but there have been different opinions on the way the sources of uncertainty are characterized and treated. This is primarily because the level 2 PSA deals with complex phenomenological processes that are deterministic in nature rather than random processes, and there are no probabilistic models characterizing them clearly. As a result, the probabilistic quantification of the level 2 PSA CET/APET is often subjected to two sources of uncertainty: (a) incomplete modeling of accident pathways or different predictions for the behavior of phenomenological events and (b) expert-to-expert variation in estimating the occurrence probability of phenomenological events. While a clear definition of the two sources of uncertainty involved in the level 2 PSA makes it possible to treat an uncertainty in a consistent manner, careless application of these different sources of uncertainty may produce different conclusions in the decision-making process. The primary purpose of this paper is to characterize typical sources of uncertainty that would often be addressed in the level 2 PSA and to provide a formal guidance for quantifying their impacts on the PSA level 2 risk results. An additional purpose of this paper is to give a formal approach on how to combine random uncertainties addressed in the level 1 PSA with subjectivistic uncertainties addressed in the level 2 PSA

  4. Spelling Errors of Iranian School-Level EFL Learners: Potential Sources

    Directory of Open Access Journals (Sweden)

    Mahnaz Saeidi

    2010-05-01

    Full Text Available With the purpose of examining the sources of spelling errors of Iranian school level EFL learners, the present researchers analyzed the dictation samples of 51 Iranian senior and junior high school male and female students majoring at an Iranian school in Baku, Azerbaijan. The content analysis of the data revealed three main sources (intralingual, interlingual, and unique with seven patterns of errors. The frequency of intralingual errors far outnumbers that of interlingual errors. Unique errors were even less. Therefore, in-service training programs may include some instruction on raising the teachers’ awareness of the different sources of errors to focus on during the teaching program.

  5. Facile approach to prepare pH and redox-responsive nanogels via Diels-Alder click reaction

    Directory of Open Access Journals (Sweden)

    C. M. Q. Le

    2018-08-01

    Full Text Available A novel pH and redox responsive system of sub-100 nm nanogels was prepared by arm-first approach via Diels-Alder click reaction. First, well-defined poly(ethylene glycol-block-poly(styrene-alt-maleic anhydride (PEG-b-PSM was synthesized and subsequently functionalized with furfuryl amine, leading to the formation of the dual-functional block copolymer of PEG-b-PSMf. The furfuryl groups in the PSMf block were employed to incorporate a redox-responsive linkage and the carboxylic acid moieties generated through functionalization acted as a pH-responsive part. The Diels-Alder click reaction between a bismaleimide crosslinker and PEG-b-PSMf was conducted at 60 °C, affording star-like nanogel structures. Doxorubicin, a model anticancer drug, was loaded into to the core of the nanogels primarily by the ionic interaction with carboxylates of core blocks and a highest drug loading capacity of 38.1% was obtained. Furthermore, the in vitro profile showed a low release percentage (11.2% of DOX at PBS pH 7.4, whereas a burst release (62% at pH 5.0 in the presence of 10 mM glutathione, indicating the effective pH and redox responsive characteristic of the PEG-b-PSMf nanogels.

  6. In vivo click reaction between Tc-99m-labeled azadibenzocyclooctyne-MAMA and 2-nitroimidazole-azide for tumor hypoxia targeting.

    Science.gov (United States)

    Sun, Wenjing; Chu, Taiwei

    2015-10-15

    The bioactivity of nitroimidazole in Tc-99m-labeled 2-nitroimidazole, a traditional solid tumor hypoxia-imaging agent for single photon emission computed tomography (SPECT), is reduced by the presence of large ligand and metallic radionuclide, exhibiting lower tumor-to-nontumor ratios. In an effort to solve this general problem, a pretargeting strategy based on click chemistry (strain-promoted cyclooctyne-azide cycloaddition) was applied. The functional click synthons were synthesized as pretargeting components: an azide group linked to 2-nitroimidazole (2NIM-Az) serves for tumor hypoxia-targeting and azadibenzocyclooctyne conjugated with monoamine monoamide dithiol ligand (AM) functions as radiolabeling and binding group to azides in vivo. 2NIM-triazole-MAMA was obtained from in vitro click reaction with a reaction rate constant of 0.98M(-1)s(-1). AM and 2NIM-triazole-MAMA were radiolabeled with Tc-99m. The hypoxia-pretargeting biodistribution was studied in Kunming mice bearing S180 tumor; (99m)Tc-AM and (99m)Tc-triazole-2NIM were used as blank control and conventional control. Compared to the control groups, the pretargeting experiment exhibits the best radio-uptake and retention in tumor, with higher tumor-to-muscle and tumor-to-blood ratios (up to 8.55 and 1.44 at 8h post-(99m)Tc-complex-injection, respectively). To some extent, the pretargeting strategy protects the bioactivity of nitroimidazole and therefore provides an innovative approach for the development of tumor hypoxia-SPECT imaging agents. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Target and identify: triazene linker helps identify azidation sites of labelled proteins via click and cleave strategy.

    Science.gov (United States)

    Lohse, Jonas; Schindl, Alexandra; Danda, Natasha; Williams, Chris P; Kramer, Karl; Kuster, Bernhard; Witte, Martin D; Médard, Guillaume

    2017-10-31

    A method for identifying probe modification of proteins via tandem mass spectrometry was developed. Azide bearing molecules are immobilized on functionalised sepharose beads via copper catalysed Huisgen-type click chemistry and selectively released under acidic conditions by chemical cleavage of the triazene linkage. We applied this method to identify the modification site of targeted-diazotransfer on BirA.

  8. Low sound level source path contribution on a HVAC

    NARCIS (Netherlands)

    Bree, H.E. de; Basten, T.G.H.

    2008-01-01

    For compliance test purposes, the noise level of a HVAC is usually measured with a pressure microphone positioned at a certain distance. This measurement is normally performed in an anechoic room. However, this method doesn't provide the engineer any insight on what noise sources do contribute to

  9. Click chemistry as a powerful and chemoselective tool for the attachment of targeting ligands to polymer drug carriers

    Czech Academy of Sciences Publication Activity Database

    Pola, Robert; Braunová, Alena; Laga, Richard; Pechar, Michal; Ulbrich, Karel

    2014-01-01

    Roč. 5, č. 4 (2014), s. 1340-1350 ISSN 1759-9954 Grant - others:AV ČR(CZ) AP0802 Program:Akademická prémie - Praemium Academiae Institutional support: RVO:61389013 Keywords : click chemistry * RAFT polymerization * hydrophilic polymers Subject RIV: CD - Macromolecular Chemistry Impact factor: 5.520, year: 2014

  10. Chandra Source Catalog: User Interfaces

    Science.gov (United States)

    Bonaventura, Nina; Evans, I. N.; Harbo, P. N.; Rots, A. H.; Tibbetts, M. S.; Van Stone, D. W.; Zografou, P.; Anderson, C. S.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, J. D.; Fabbiano, G.; Galle, E.; Gibbs, D. G.; Glotfelty, K. J.; Grier, J. D.; Hain, R.; Hall, D. M.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McCollough, M. L.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Primini, F. A.; Refsdal, B. L.; Siemiginowska, A. L.; Sundheim, B. A.; Winkelman, S. L.

    2010-03-01

    The CSCview data mining interface is available for browsing the Chandra Source Catalog (CSC) and downloading tables of quality-assured source properties and data products. Once the desired source properties and search criteria are entered into the CSCview query form, the resulting source matches are returned in a table along with the values of the requested source properties for each source. (The catalog can be searched on any source property, not just position.) At this point, the table of search results may be saved to a text file, and the available data products for each source may be downloaded. CSCview save files are output in RDB-like and VOTable format. The available CSC data products include event files, spectra, lightcurves, and images, all of which are processed with the CIAO software. CSC data may also be accessed non-interactively with Unix command-line tools such as cURL and Wget, using ADQL 2.0 query syntax. In fact, CSCview features a separate ADQL query form for those who wish to specify this type of query within the GUI. Several interfaces are available for learning if a source is included in the catalog (in addition to CSCview): 1) the CSC interface to Sky in Google Earth shows the footprint of each Chandra observation on the sky, along with the CSC footprint for comparison (CSC source properties are also accessible when a source within a Chandra field-of-view is clicked); 2) the CSC Limiting Sensitivity online tool indicates if a source at an input celestial location was too faint for detection; 3) an IVOA Simple Cone Search interface locates all CSC sources within a specified radius of an R.A. and Dec.; and 4) the CSC-SDSS cross-match service returns the list of sources common to the CSC and SDSS, either all such sources or a subset based on search criteria.

  11. PBODL : Parallel Bayesian Online Deep Learning for Click-Through Rate Prediction in Tencent Advertising System

    OpenAIRE

    Liu, Xun; Xue, Wei; Xiao, Lei; Zhang, Bo

    2017-01-01

    We describe a parallel bayesian online deep learning framework (PBODL) for click-through rate (CTR) prediction within today's Tencent advertising system, which provides quick and accurate learning of user preferences. We first explain the framework with a deep probit regression model, which is trained with probabilistic back-propagation in the mode of assumed Gaussian density filtering. Then we extend the model family to a variety of bayesian online models with increasing feature embedding ca...

  12. Echolocation signals of free-ranging Indo-Pacific humpback dolphins (Sousa chinensis) in Sanniang Bay, China.

    Science.gov (United States)

    Fang, Liang; Li, Songhai; Wang, Kexiong; Wang, Zhitao; Shi, Wenjing; Wang, Ding

    2015-09-01

    While the low-frequency communication sounds of Indo-Pacific humpback dolphins (Sousa chinensis) have been reported in a number of papers, the high-frequency echolocation signals of Sousa chinensis, especially those living in the wild, have been less studied. In the current study, echolocation signals of humpback dolphins were recorded in Sanniang Bay, Guangxi Province, China, using a cross-type hydrophone array with five elements. In total, 77 candidate on-axis clicks from 77 scans were selected for analysis. The results showed that the varied peak-to-peak source levels ranged from 177.1 to 207.3 dB, with an average of 187.7 dB re: 1 μPa. The mean peak frequency was 109.0 kHz with a -3-dB bandwidth of 50.3 kHz and 95% energy duration of 22 μs. The -3-dB bandwidth was much broader than the root mean square bandwidth and exhibited a bimodal distribution. The center frequency exhibited a positive relationship with the peak-to-peak source level. The clicks of the wild Indo-Pacific humpback dolphins were short-duration, broadband, ultrasonic pulses, similar to those produced by other whistling dolphins of similar body size. However, the click source levels of the Indo-Pacific humpback dolphin appear to be lower than those of other whistling dolphins.

  13. Effects of dietary oil sources and calcium : phosphorus levels on ...

    African Journals Online (AJOL)

    The study investigated the effects of varying dietary calcium (Ca) levels and sources of oil on performance of broiler chickens. A total of 378 one-day-old birds were fed 6% palm oil (PO), soybean oil (SO) or linseed oil (LO) in combination with three levels of Ca, 1%, 1.25% and 1.5%, for six weeks in a 3 x 3 factorial ...

  14. Integrating the Visual Arts Back into the Classroom with Mobile Applications: Teaching beyond the "Click and View" Approach

    Science.gov (United States)

    Katz-Buonincontro, Jen; Foster, Aroutis

    2013-01-01

    Teachers can use mobile applications to integrate the visual arts back into the classroom, but how? This article generates recommendations for selecting and using well-designed mobile applications in the visual arts beyond a "click and view " approach. Using quantitative content analysis, the results show the extent to which a sample of…

  15. Three-Level Z-Source Inverters Using a Single LC Impedance Network

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Lim, Sok Wei; Gao, Feng

    2007-01-01

    two LC impedance networks and two isolated dc sources, which can significantly increase the overall system cost and require a more complex modulator for balancing the network inductive voltage boosting. Offering a number of less costly alternatives, this letter presents the design and control of two...... three-level Z-source inverters, whose output voltage can be stepped down or up using only a single LC impedance network connected between the dc input source and either a neutral-point-clamped (NPC) or dc-link cascaded inverter circuitry. Through careful design of their modulation scheme, both inverters...

  16. Age-Related Changes in Binaural Interaction at Brainstem Level.

    Science.gov (United States)

    Van Yper, Lindsey N; Vermeire, Katrien; De Vel, Eddy F J; Beynon, Andy J; Dhooge, Ingeborg J M

    2016-01-01

    Age-related hearing loss hampers the ability to understand speech in adverse listening conditions. This is attributed to a complex interaction of changes in the peripheral and central auditory system. One aspect that may deteriorate across the lifespan is binaural interaction. The present study investigates binaural interaction at the level of the auditory brainstem. It is hypothesized that brainstem binaural interaction deteriorates with advancing age. Forty-two subjects of various age participated in the study. Auditory brainstem responses (ABRs) were recorded using clicks and 500 Hz tone-bursts. ABRs were elicited by monaural right, monaural left, and binaural stimulation. Binaural interaction was investigated in two ways. First, grand averages of the binaural interaction component were computed for each age group. Second, wave V characteristics of the binaural ABR were compared with those of the summed left and right ABRs. Binaural interaction in the click ABR was demonstrated by shorter latencies and smaller amplitudes in the binaural compared with the summed monaural responses. For 500 Hz tone-burst ABR, no latency differences were found. However, amplitudes were significantly smaller in the binaural than summed monaural condition. An age-effect was found for 500 Hz tone-burst, but not for click ABR. Brainstem binaural interaction seems to decline with age. Interestingly, these changes seem to be stimulus-dependent.

  17. "Click" synthesis of fatty acid derivatives as fast-degrading polyanhydride precursors.

    Science.gov (United States)

    Lluch, Cristina; Lligadas, Gerard; Ronda, Joan C; Galià, Marina; Cadiz, Virginia

    2011-09-01

    Fast-degrading linear and branched polyanhydrides are obtained by melt-condensation of novel di- and tri-carboxylic acid monomers based on oleic and undecylenic acid synthesized using photoinitiated thiol-ene click chemistry. (1)H NMR spectroscopy, size exclusion chromatography, differential scanning calorimetry, thermogravimetric analysis, and FT-IR spectroscopy have been used to fully characterize these polymers. The hydrolytic degradation of these polymers was studied by means of weight loss, anhydride bond loss, and changes in molecular weight, showing fast degrading properties. Drug release studies from the synthesized polyanhydrides have also been conducted, using rhodamine B as a hydrophobic model drug, to evaluate the potential of these polymers in biomedical applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Indirect photopatterning of functionalized organic monolayers via copper-catalyzed "click chemistry"

    Science.gov (United States)

    Williams, Mackenzie G.; Teplyakov, Andrew V.

    2018-07-01

    Solution-based lithographic surface modification of an organic monolayer on a solid substrate is attained based on selective area photo-reduction of copper (II) to copper (I) to catalyze the azide-alkyne dipolar cycloaddition "click" reaction. X-ray photoelectron spectroscopy is used to confirm patterning, and spectroscopic results are analyzed and supplemented with computational models to confirm the surface chemistry. It is determined that this surface modification approach requires irradiation of the solid substrate with all necessary components present in solution. This method requires only minutes of irradiation to result in spatial and temporal control of the covalent surface functionalization of a monolayer and offers the potential for wavelength tunability that may be desirable in many applications utilizing organic monolayers.

  19. A New Approach for Mobile Advertising Click-Through Rate Estimation Based on Deep Belief Nets

    OpenAIRE

    Chen, Jie-Hao; Zhao, Zi-Qian; Shi, Ji-Yun; Zhao, Chong

    2017-01-01

    In recent years, with the rapid development of mobile Internet and its business applications, mobile advertising Click-Through Rate (CTR) estimation has become a hot research direction in the field of computational advertising, which is used to achieve accurate advertisement delivery for the best benefits in the three-side game between media, advertisers, and audiences. Current research on the estimation of CTR mainly uses the methods and models of machine learning, such as linear model or re...

  20. Neural responses in the primary auditory cortex of freely behaving cats while discriminating fast and slow click-trains.

    Science.gov (United States)

    Dong, Chao; Qin, Ling; Liu, Yongchun; Zhang, Xinan; Sato, Yu

    2011-01-01

    Repeated acoustic events are ubiquitous temporal features of natural sounds. To reveal the neural representation of the sound repetition rate, a number of electrophysiological studies have been conducted on various mammals and it has been proposed that both the spike-time and firing rate of primary auditory cortex (A1) neurons encode the repetition rate. However, previous studies rarely examined how the experimental animals perceive the difference in the sound repetition rate, and a caveat to these experiments is that they compared physiological data obtained from animals with psychophysical data obtained from humans. In this study, for the first time, we directly investigated acoustic perception and the underlying neural mechanisms in the same experimental animal by examining spike activities in the A1 of free-moving cats while performing a Go/No-go task to discriminate the click-trains at different repetition rates (12.5-200 Hz). As reported by previous studies on passively listening animals, A1 neurons showed both synchronized and non-synchronized responses to the click-trains. We further found that the neural performance estimated from the precise temporal information of synchronized units was good enough to distinguish all 16.7-200 Hz from the 12.5 Hz repetition rate; however, the cats showed declining behavioral performance with the decrease of the target repetition rate, indicating an increase of difficulty in discriminating two slower click-trains. Such behavioral performance was well explained by the firing rate of some synchronized and non-synchronized units. Trial-by-trial analysis indicated that A1 activity was not affected by the cat's judgment of behavioral response. Our results suggest that the main function of A1 is to effectively represent temporal signals using both spike timing and firing rate, while the cats may read out the rate-coding information to perform the task in this experiment.

  1. Neural responses in the primary auditory cortex of freely behaving cats while discriminating fast and slow click-trains.

    Directory of Open Access Journals (Sweden)

    Chao Dong

    Full Text Available Repeated acoustic events are ubiquitous temporal features of natural sounds. To reveal the neural representation of the sound repetition rate, a number of electrophysiological studies have been conducted on various mammals and it has been proposed that both the spike-time and firing rate of primary auditory cortex (A1 neurons encode the repetition rate. However, previous studies rarely examined how the experimental animals perceive the difference in the sound repetition rate, and a caveat to these experiments is that they compared physiological data obtained from animals with psychophysical data obtained from humans. In this study, for the first time, we directly investigated acoustic perception and the underlying neural mechanisms in the same experimental animal by examining spike activities in the A1 of free-moving cats while performing a Go/No-go task to discriminate the click-trains at different repetition rates (12.5-200 Hz. As reported by previous studies on passively listening animals, A1 neurons showed both synchronized and non-synchronized responses to the click-trains. We further found that the neural performance estimated from the precise temporal information of synchronized units was good enough to distinguish all 16.7-200 Hz from the 12.5 Hz repetition rate; however, the cats showed declining behavioral performance with the decrease of the target repetition rate, indicating an increase of difficulty in discriminating two slower click-trains. Such behavioral performance was well explained by the firing rate of some synchronized and non-synchronized units. Trial-by-trial analysis indicated that A1 activity was not affected by the cat's judgment of behavioral response. Our results suggest that the main function of A1 is to effectively represent temporal signals using both spike timing and firing rate, while the cats may read out the rate-coding information to perform the task in this experiment.

  2. Brick and Click Libraries: Proceedings of an Academic Library Symposium (Northwest Missouri State University, Maryville, Missouri, October 14, 2005)

    Science.gov (United States)

    Ury, Connie Jo., Ed.; Baudino, Frank, Ed.

    2005-01-01

    These proceedings document the fifth year of the "Brick and Click Libraries Symposium", held annually at Northwest Missouri State University in Maryville, Missouri. Thirty five peer-reviewed papers and abstracts, written by academic librarians, and presented at the symposium are included in this volume. Many of the entries have…

  3. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor-Failure Conditions

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2009-01-01

    This paper evaluates and proposes various compensation methods for three-level Z-source inverters under semiconductor-failure conditions. Unlike the fault-tolerant techniques used in traditional three-level inverters, where either an extra phase-leg or collective switching states are used......, the proposed methods for three-level Z-source inverters simply reconfigure their relevant gating signals so as to ride-through the failed semiconductor conditions smoothly without any significant decrease in their ac-output quality and amplitude. These features are partly attributed to the inherent boost...... under semiconductor-failure conditions. For verifying these described performance features, PLECS simulation and experimental testing were performed with some results captured and shown in a later section for visual confirmation....

  4. Cu-Click Compatible Triazabutadienes To Expand the Scope of Aryl Diazonium Ion Chemistry.

    Science.gov (United States)

    Cornali, Brandon M; Kimani, Flora W; Jewett, John C

    2016-10-07

    Triazabutadienes can be used to readily generate reactive aryl diazonium ions under mild, physiologically relevant conditions. These conditions are compatible with a range of functionalities that do not tolerate traditional aryl diazonium ion generation. To increase the utility of this aryl diazonium ion releasing chemistry an alkyne-containing triazabutadiene was synthesized. The copper-catalyzed azide-alkyne cycloaddition ("Cu-click") reaction was utilized to modify the alkyne-containing triazabutadiene and shown to be compatible with the nitrogen-rich triazabutadiene. One of the triazole products was tethered to a fluorophore, thus enabling the direct fluorescent labeling of a model protein.

  5. Magnetite nanoparticles coated with alkyne-containing polyacrylates for click chemistry

    Science.gov (United States)

    Socaci, Crina; Rybka, Miriam; Magerusan, Lidia; Nan, Alexandrina; Turcu, Rodica; Liebscher, Jürgen

    2013-06-01

    New magnetic core shell nanoparticles were synthesized consisting of magnetite cores and poly-( O-propargyl acrylate) shells. Strong fixing of the shells was achieved by primary anchoring phosphates or α-dihydroxydiphosphonates containing acrylate or methacrylate functionalities. The magnetic nanoparticles are attractive as supports for a variety of function which can be easily introduced by Cu-catalyzed alkyne azide cycloaddition (CuAAC, a click reaction). In this way, also the loading of the magnetic nanoparticles with propargyl units was determined by reaction with 4-azidoacetophenone and analysis of the supernatant. In order to demonstrate the attractiveness of the magnetic nanoparticles a novel azido-containing conjugate with biotin as recognition function and dansyl as fluorescence marker was introduced by CuAAC reaction. All NP show superparamagnetic behavior with high-saturation magnetization values and were further characterized by FTIR, photoelectron spectroscopy and TEM.

  6. Magnetite nanoparticles coated with alkyne-containing polyacrylates for click chemistry

    International Nuclear Information System (INIS)

    Socaci, Crina; Rybka, Miriam; Magerusan, Lidia; Nan, Alexandrina; Turcu, Rodica; Liebscher, Jürgen

    2013-01-01

    New magnetic core shell nanoparticles were synthesized consisting of magnetite cores and poly-(O-propargyl acrylate) shells. Strong fixing of the shells was achieved by primary anchoring phosphates or α-dihydroxydiphosphonates containing acrylate or methacrylate functionalities. The magnetic nanoparticles are attractive as supports for a variety of function which can be easily introduced by Cu-catalyzed alkyne azide cycloaddition (CuAAC, a click reaction). In this way, also the loading of the magnetic nanoparticles with propargyl units was determined by reaction with 4-azidoacetophenone and analysis of the supernatant. In order to demonstrate the attractiveness of the magnetic nanoparticles a novel azido-containing conjugate with biotin as recognition function and dansyl as fluorescence marker was introduced by CuAAC reaction. All NP show superparamagnetic behavior with high-saturation magnetization values and were further characterized by FTIR, photoelectron spectroscopy and TEM.

  7. Magnetite nanoparticles coated with alkyne-containing polyacrylates for click chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Socaci, Crina [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania); Rybka, Miriam [Humboldt-University Berlin, Department of Chemistry (Germany); Magerusan, Lidia; Nan, Alexandrina; Turcu, Rodica; Liebscher, Juergen, E-mail: liebscher@chemie.hu-berlin.de [National Institute of Research and Development for Isotopic and Molecular Technologies (Romania)

    2013-06-15

    New magnetic core shell nanoparticles were synthesized consisting of magnetite cores and poly-(O-propargyl acrylate) shells. Strong fixing of the shells was achieved by primary anchoring phosphates or {alpha}-dihydroxydiphosphonates containing acrylate or methacrylate functionalities. The magnetic nanoparticles are attractive as supports for a variety of function which can be easily introduced by Cu-catalyzed alkyne azide cycloaddition (CuAAC, a click reaction). In this way, also the loading of the magnetic nanoparticles with propargyl units was determined by reaction with 4-azidoacetophenone and analysis of the supernatant. In order to demonstrate the attractiveness of the magnetic nanoparticles a novel azido-containing conjugate with biotin as recognition function and dansyl as fluorescence marker was introduced by CuAAC reaction. All NP show superparamagnetic behavior with high-saturation magnetization values and were further characterized by FTIR, photoelectron spectroscopy and TEM.

  8. Click chemistry approach to conventional vegetable tanning process: accelerated method with improved organoleptic properties.

    Science.gov (United States)

    Krishnamoorthy, Ganesan; Ramamurthy, Govindaswamy; Sadulla, Sayeed; Sastry, Thotapalli Parvathaleswara; Mandal, Asit Baran

    2014-09-01

    Click chemistry approaches are tailored to generate molecular building blocks quickly and reliably by joining small units together selectively and covalently, stably and irreversibly. The vegetable tannins such as hydrolyzable and condensed tannins are capable to produce rather stable radicals or inhibit the progress of radicals and are prone to oxidations such as photo and auto-oxidation, and their anti-oxidant nature is well known. A lot remains to be done to understand the extent of the variation of leather stability, color variation (lightening and darkening reaction of leather), and poor resistance to water uptake for prolonged periods. In the present study, we have reported click chemistry approaches to accelerated vegetable tanning processes based on periodates catalyzed formation of oxidized hydrolysable and condensed tannins for high exhaustion with improved properties. The distribution of oxidized vegetable tannin, the thermal stability such as shrinkage temperature (T s) and denaturation temperature (T d), resistance to collagenolytic activities, and organoleptic properties of tanned leather as well as the evaluations of eco-friendly characteristics were investigated. Scanning electron microscopic analysis indicates the cross section of tightness of the leather. Differential scanning calorimetric analysis shows that the T d of leather is more than that of vegetable tanned or equal to aldehyde tanned one. The leathers exhibited fullness, softness, good color, and general appearance when compared to non-oxidized vegetable tannin. The developed process benefits from significant reduction in total solids and better biodegradability in the effluent, compared to non-oxidized vegetable tannins.

  9. Offshore dredger sounds: Source levels, sound maps, and risk assessment

    NARCIS (Netherlands)

    Jong, C.A.F. de; Ainslie, M.A.; Heinis, F.; Janmaat, J.

    2016-01-01

    The underwater sound produced during construction of the Port of Rotterdam harbor extension (Maasvlakte 2) was measured, with emphasis on the contribution of the trailing suction hopper dredgers during their various activities: dredging, transport, and discharge of sediment. Measured source levels

  10. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2007-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...

  11. Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

    Science.gov (United States)

    Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

    2015-04-01

    As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Indoor air quality in Portuguese schools: levels and sources of pollutants.

    Science.gov (United States)

    Madureira, J; Paciência, I; Pereira, C; Teixeira, J P; Fernandes, E de O

    2016-08-01

    Indoor air quality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM2.5 , PM10 , bacteria and fungi, carbon dioxide (CO2 ), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO2 and occupancy data. Concentrations of CO2 exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 μg/m(3) ) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations, and CO2 levels between schools exceeded the variability within schools. These findings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behavior, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  13. Effects of irradiation source and dose level on quality characteristics of processed meat products

    Science.gov (United States)

    Ham, Youn-Kyung; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Choi, Yun-Sang; Song, Beom-Seok; Park, Jong-Heum; Kim, Cheon-Jei

    2017-01-01

    The effect of irradiation source (gamma-ray, electron-beam, and X-ray) and dose levels on the physicochemical, organoleptic and microbial properties of cooked beef patties and pork sausages was studied, during 10 days of storage at 30±1 °C. The processed meat products were irradiated at 0, 2.5, 5, 7.5, and 10 kGy by three different irradiation sources. The pH of cooked beef patties and pork sausages was unaffected by irradiation sources or their doses. The redness of beef patties linearly decreased with increasing dose level (Pchanges in overall acceptability were observed for pork sausages regardless of irradiation source (P>0.05), while gamma-ray irradiated beef patties showed significantly decreased overall acceptability in a dose-dependent manner (Poxidation of samples was accelerated by irradiation depending on irradiation sources and dose levels during storage at 30 °C. E-beam reduced total aerobic bacteria of beef patties more effectively, while gamma-ray considerably decreased microbes in pork sausages as irradiation dose increased. The results of this study indicate that quality attributes of meat products, in particular color, lipid oxidation, and microbial properties are significantly influenced by the irradiation sources.

  14. STATCONT: A statistical continuum level determination method for line-rich sources

    Science.gov (United States)

    Sánchez-Monge, Á.; Schilke, P.; Ginsburg, A.; Cesaroni, R.; Schmiedeke, A.

    2018-01-01

    STATCONT is a python-based tool designed to determine the continuum emission level in spectral data, in particular for sources with a line-rich spectrum. The tool inspects the intensity distribution of a given spectrum and automatically determines the continuum level by using different statistical approaches. The different methods included in STATCONT are tested against synthetic data. We conclude that the sigma-clipping algorithm provides the most accurate continuum level determination, together with information on the uncertainty in its determination. This uncertainty can be used to correct the final continuum emission level, resulting in the here called `corrected sigma-clipping method' or c-SCM. The c-SCM has been tested against more than 750 different synthetic spectra reproducing typical conditions found towards astronomical sources. The continuum level is determined with a discrepancy of less than 1% in 50% of the cases, and less than 5% in 90% of the cases, provided at least 10% of the channels are line free. The main products of STATCONT are the continuum emission level, together with a conservative value of its uncertainty, and datacubes containing only spectral line emission, i.e., continuum-subtracted datacubes. STATCONT also includes the option to estimate the spectral index, when different files covering different frequency ranges are provided.

  15. Developing topic-specific search filters for PubMed with click-through data.

    Science.gov (United States)

    Li, J; Lu, Z

    2013-01-01

    Search filters have been developed and demonstrated for better information access to the immense and ever-growing body of publications in the biomedical domain. However, to date the number of filters remains quite limited because the current filter development methods require significant human efforts in manual document review and filter term selection. In this regard, we aim to investigate automatic methods for generating search filters. We present an automated method to develop topic-specific filters on the basis of users' search logs in PubMed. Specifically, for a given topic, we first detect its relevant user queries and then include their corresponding clicked articles to serve as the topic-relevant document set accordingly. Next, we statistically identify informative terms that best represent the topic-relevant document set using a background set composed of topic irrelevant articles. Lastly, the selected representative terms are combined with Boolean operators and evaluated on benchmark datasets to derive the final filter with the best performance. We applied our method to develop filters for four clinical topics: nephrology, diabetes, pregnancy, and depression. For the nephrology filter, our method obtained performance comparable to the state of the art (sensitivity of 91.3%, specificity of 98.7%, precision of 94.6%, and accuracy of 97.2%). Similarly, high-performing results (over 90% in all measures) were obtained for the other three search filters. Based on PubMed click-through data, we successfully developed a high-performance method for generating topic-specific search filters that is significantly more efficient than existing manual methods. All data sets (topic-relevant and irrelevant document sets) used in this study and a demonstration system are publicly available at http://www.ncbi.nlm.nih.gov/CBBresearch/Lu/downloads/CQ_filter/

  16. Comparison of three-phase three-level voltage source inverter with intermediate dc–dc boost converter and quasi-Z-source inverter

    DEFF Research Database (Denmark)

    Panfilov, Dmitry; Husev, Oleksandr; Blaabjerg, Frede

    2016-01-01

    This study compares a three-phase three-level voltage source inverter with an intermediate dc-dc boost converter and a quasi-Z-source inverter in terms of passive elements values and dimensions, semiconductor stresses, and overall efficiency. A comparative analysis was conducted with relative...

  17. Synthesis of New 3-(2-Chloroquinolin-3-yl)-5-Phenylisoxazole Derivatives via Click-Chemistry Approach

    International Nuclear Information System (INIS)

    Fernández-Galleguillos, Carlos; Saavedra, Luis A.; Gutierrez, Margarita

    2014-01-01

    Herein, we report the synthesis of new substituted 3-(2-chloroquinolin-3-yl)-5-phenylisoxazole (3a-j) by click chemistry in good to moderate yields. This approach is based on the regioselective copper(I)-catalyzed cycloaddition between different nitrile oxides derived from 2-chloroquinoline- 3-carbaldehyde (2a-j) and phenylacetylene. Finally these derivatives were screened for their antibacterial evaluation in vitro against three Gram-negative clinical bacteria: Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii using standard methods. (author)

  18. Synthesis of New 3-(2-Chloroquinolin-3-yl)-5-Phenylisoxazole Derivatives via Click-Chemistry Approach

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Galleguillos, Carlos; Saavedra, Luis A.; Gutierrez, Margarita [Laboratorio de Sintesis Organica, Instituto de Quimica de Recursos Naturales, Universidad de Talca (Chile)

    2014-02-15

    Herein, we report the synthesis of new substituted 3-(2-chloroquinolin-3-yl)-5-phenylisoxazole (3a-j) by click chemistry in good to moderate yields. This approach is based on the regioselective copper(I)-catalyzed cycloaddition between different nitrile oxides derived from 2-chloroquinoline- 3-carbaldehyde (2a-j) and phenylacetylene. Finally these derivatives were screened for their antibacterial evaluation in vitro against three Gram-negative clinical bacteria: Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumannii using standard methods. (author)

  19. Self-Plasticization of PVC via click reaction of a monooctyl phthalate derivative

    Directory of Open Access Journals (Sweden)

    Jia Puyou

    2017-09-01

    Full Text Available Modified PVC (M-PVC material with suppressed migration and low glass transition temperature was prepared via click reaction of a monooctyl phthalate derivative. Chemical structure and composition of M-PVC were characterized by FT-IR, 1H NMR and element analysis. Thermal stability, glass transition temperature and migration stability of M-PVC were studied with TGA, DSC and migration tests, respectively. The study showed that M-PVC exhibited poor thermal stability, and low glass transition temperature of 66.0°C. No migration was found in distilled water, 10% (v/v ethanol, 30% (w/vacetic acid and petroleum ether. The PVC material is expected to preparing PVC products in the areas with high migration resistance requirement.

  20. Effect of Knowledge Sources on Firm Level Innovation in Tanzania

    NARCIS (Netherlands)

    Osoro, O.; Vermeulen, P.A.M.; Knoben, J.; Kahyarara, G.

    2016-01-01

    This paper analyses the impact of different sources of knowledge on product and process innovation in Tanzania using firm-level data. We specifically analyse the separate impacts of internal knowledge, external knowledge and the combined impact of both types of knowledge on firms’ product and

  1. Ambient levels of carbonyl compounds and their sources in Guangzhou, China

    Science.gov (United States)

    Feng, Yanli; Wen, Sheng; Chen, Yingjun; Wang, Xinming; Lü, Huixiong; Bi, Xinhui; Sheng, Guoying; Fu, Jiamo

    Ambient levels of carbonyl compounds and their possible sources, vehicular exhaust and cooking exhaust, were studied at seven places in Guangzhou, including five districts (a residential area, an industrial area, a botanical garden, a downtown area and a semi-rural area), a bus station and a restaurant during the period of June-September 2003. Nineteen carbonyl compounds were identified in the ambient air, of which acetone was the most abundant carbonyl, followed by formaldehyde and acetaldehyde. Only little changes were found in carbonyl concentration levels in the five different districts because of their dispersion and mixture in the atmosphere in summer. The lower correlations between the carbonyls' concentrations might result from the mixture of carbonyls derived from different sources, including strong photochemical reactions at noon in summer. Formaldehyde and acetaldehyde were the main carbonyls in bus station, while straight-chain carbonyls were comparatively abundant in cooking exhaust. Besides vehicular exhaust, cooking might be another major source of carbonyl compounds in Guangzhou City, especially for high molecular weight carbonyls.

  2. Predicting user click behaviour in search engine advertisements

    Science.gov (United States)

    Daryaie Zanjani, Mohammad; Khadivi, Shahram

    2015-10-01

    According to the specific requirements and interests of users, search engines select and display advertisements that match user needs and have higher probability of attracting users' attention based on their previous search history. New objects such as user, advertisement or query cause a deterioration of precision in targeted advertising due to their lack of history. This article surveys this challenge. In the case of new objects, we first extract similar observed objects to the new object and then we use their history as the history of new object. Similarity between objects is measured based on correlation, which is a relation between user and advertisement when the advertisement is displayed to the user. This method is used for all objects, so it has helped us to accurately select relevant advertisements for users' queries. In our proposed model, we assume that similar users behave in a similar manner. We find that users with few queries are similar to new users. We will show that correlation between users and advertisements' keywords is high. Thus, users who pay attention to advertisements' keywords, click similar advertisements. In addition, users who pay attention to specific brand names might have similar behaviours too.

  3. Protocol of source shielding maintenance in a level measurement systems

    International Nuclear Information System (INIS)

    Gonzales, E.; Figueroa, J.

    1996-01-01

    Maintenance labor of the source shielding and locking system is not performed in many Venezuelan enterprises that employ radioactive level gauge in large container. The lack of maintenance and the ambient long lasting action have produced impairment of many devices and their given parts rise to economical and radiological protection problems. In order to help to solve the mentioned problems, principally to reduce the unjustified dose to workers, the IVIC Health Physics Service worked out a protocol to perform, in a safety way, the maintenance of source shielding and its locking system. This protocol is presented in this paper. (authors)

  4. Automatic Classification of Users' Health Information Need Context: Logistic Regression Analysis of Mouse-Click and Eye-Tracker Data.

    Science.gov (United States)

    Pian, Wenjing; Khoo, Christopher Sg; Chi, Jianxing

    2017-12-21

    (Puser's type of health information context with a 10-fold cross validation mean accuracy of 84% (62/74), followed by model 2 at 73% (54/74) and model 1 at 71% (52/78). In addition, correlation analysis found that particular browsing durations were highly correlated with users' age, education level, and the urgency of their information need. A user's type of health information need context (ie, searching for self, for others, or with no health issue in mind) can be identified with reasonable accuracy using just user mouse clicks that can easily be detected by Web applications. Higher accuracy can be obtained using Google glass or future computing devices with eye tracking function. ©Wenjing Pian, Christopher SG Khoo, Jianxing Chi. Originally published in the Journal of Medical Internet Research (http://www.jmir.org), 21.12.2017.

  5. Click-PEGylation - A mobility shift approach to assess the redox state of cysteines in candidate proteins.

    Science.gov (United States)

    van Leeuwen, Lucie A G; Hinchy, Elizabeth C; Murphy, Michael P; Robb, Ellen L; Cochemé, Helena M

    2017-07-01

    The redox state of cysteine thiols is critical for protein function. Whereas cysteines play an important role in the maintenance of protein structure through the formation of internal disulfides, their nucleophilic thiol groups can become oxidatively modified in response to diverse redox challenges and thereby function in signalling and antioxidant defences. These oxidative modifications occur in response to a range of agents and stimuli, and can lead to the existence of multiple redox states for a given protein. To assess the role(s) of a protein in redox signalling and antioxidant defence, it is thus vital to be able to assess which of the multiple thiol redox states are present and to investigate how these alter under different conditions. While this can be done by a range of mass spectrometric-based methods, these are time-consuming, costly, and best suited to study abundant proteins or to perform an unbiased proteomic screen. One approach that can facilitate a targeted assessment of candidate proteins, as well as proteins that are low in abundance or proteomically challenging, is by electrophoretic mobility shift assays. Redox-modified cysteine residues are selectively tagged with a large group, such as a polyethylene glycol (PEG) polymer, and then the proteins are separated by electrophoresis followed by immunoblotting, which allows the inference of redox changes based on band shifts. However, the applicability of this method has been impaired by the difficulty of cleanly modifying protein thiols by large PEG reagents. To establish a more robust method for redox-selective PEGylation, we have utilised a Click chemistry approach, where free thiol groups are first labelled with a reagent modified to contain an alkyne moiety, which is subsequently Click-reacted with a PEG molecule containing a complementary azide function. This strategy can be adapted to study reversibly reduced or oxidised cysteines. Separation of the thiol labelling step from the PEG

  6. Approaches to assign security levels for radioactive substances and radiation sources

    International Nuclear Information System (INIS)

    Ivanov, M.V.; Petrovskij, N.P.; Pinchuk, G.N.; Telkov, S.N.; Kuzin, V.V.

    2011-01-01

    The article contains analyzed provisions on categorization of radioactive substances and radiation sources according to the extent of their potential danger. Above provisions are used in the IAEA documents and in Russian regulatory documents for differentiation of regulatory requirements to physical security. It is demonstrated that with the account of possible threats of violators, rules of physical protection of radiation sources and radioactive substances should be amended as regards the approaches to assign their categories and security levels [ru

  7. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhen-Bei, E-mail: 1021453457@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Wu, Jing-Jing, E-mail: 957522275@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Su, Yu, E-mail: 819388710@qq.com [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Zhou, Jin, E-mail: zhoujin_ah@163.com [Department of Materials and Chemical Engineering, Chizhou University, Muzhi Rd. 199, Chizhou, Anhui 247000 (China); Gao, Yong, E-mail: 154682180@qq.com [School of Chemistry and Environmental Engineering, Jiangsu University of Technology, Changzhou 213001 (China); Yu, Hai-Yin, E-mail: yhy456@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China); Gu, Jia-Shan, E-mail: jiashanG@mail.ahnu.edu.cn [The Key Laboratory of Functional Molecular Solids, Ministry of Education, Anhui Key Laboratory of Molecular-Based Materials, College of Chemistry and Materials Science, Anhui Normal University, East Beijing Rd. 1, Wuhu, Anhui 241000 (China)

    2015-03-30

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S{sub N}2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface.

  8. Layer-by-layer assembly of graphene oxide on polypropylene macroporous membranes via click chemistry to improve antibacterial and antifouling performance

    International Nuclear Information System (INIS)

    Zhang, Zhen-Bei; Wu, Jing-Jing; Su, Yu; Zhou, Jin; Gao, Yong; Yu, Hai-Yin; Gu, Jia-Shan

    2015-01-01

    Graphical abstract: - Highlights: • Clickable membrane prepared by photo bromination and S N 2 nucleophilic substitution. • Azide graphene oxide prepared by ring-opening reaction. • Alkyne graphene oxide was prepared via esterification reaction. • Layer-by-layer assembly of graphene oxide on membrane by click chemistry. • Antibacterial and antifouling characteristics were enhanced greatly. - Abstract: Polypropylene is an extensively used membrane material; yet, polypropylene membranes exhibit extremely poor resistance to protein fouling. To ameliorate this issue, graphene oxide (GO) nanosheets were used to modify macroporous polypropylene membrane (MPPM) via layer-by-layer assembly technique through click reaction. First, alkyne-terminated GO was prepared through esterification between carboxyl groups in GO and amide groups in propargylamine; azide-terminated GO was synthesized by the ring-opening reaction of epoxy groups in GO with sodium azide. Second, GO was introduced to the membrane by click chemistry. Characterizations of infrared spectra and X-ray photoelectron spectroscopy confirmed the modification. The sharply decreasing of static water contact angle indicated the improvement of the surface hydrophilicity for GO modified membrane. Introducing GO to the membrane results in a dramatic increase of water flux, improvements in the antifouling characteristics and antibacterial property for the membranes. The pure water flux through the 5-layered GO modified membrane is 1.82 times that through the unmodified one. The water flux restores to 43.0% for the unmodified membrane while to 79.8% for the modified membrane. The relative flux reduction decreases by 32.1% due to GO modification. The antibacterial property was also enhanced by two-thirds. These results demonstrate that the antifouling and antibacterial characteristics can be raised by tethering GO to the membrane surface

  9. A versatile method for the preparation of conjugates of peptides with DNA/PNA/analog by employing chemo-selective click reaction in water

    Science.gov (United States)

    Gogoi, Khirud; Mane, Meenakshi V.; Kunte, Sunita S.; Kumar, Vaijayanti A.

    2007-01-01

    The specific 1,3 dipolar Hüisgen cycloaddition reaction known as ‘click-reaction’ between azide and alkyne groups is employed for the synthesis of peptide–oligonucleotide conjugates. The peptide nucleic acids (PNA)/DNA and peptides may be appended either by azide or alkyne groups. The cycloaddition reaction between the azide and alkyne appended substrates allows the synthesis of the desired conjugates in high purity and yields irrespective of the sequence and functional groups on either of the two substrates. The versatile approach could also be employed to generate the conjugates of peptides with thioacetamido nucleic acid (TANA) analog. The click reaction is catalyzed by Cu (I) in either water or in organic medium. In water, ∼3-fold excess of the peptide-alkyne/azide drives the reaction to completion in 2 h with no side products. PMID:17981837

  10. Arsenic levels in groundwater aquifer of the Neoplanta source area ...

    African Journals Online (AJOL)

    As part of a survey on the groundwater aquifer at the Neoplanta source site, standard laboratory analysis of water quality and an electromagnetic geophysical method were used for long-term quantitative and qualitative monitoring of arsenic levels. This study presents only the results of research conducted in the ...

  11. Effect of Knowledge Sources on Firm Level Innovation in Tanzania

    NARCIS (Netherlands)

    Osoro, Otieno; Kahyarara, Godius; Knoben, Joris; Vermeulen, P.A.M.

    In this paper we analyse the impact of different sources of knowledge on product innovation in Tanzania using firm level data from 543 firms. Specifically, we assess the separate impacts of internal knowledge and external knowledge and the combined impact of both on a firm’s likelihood of

  12. Site-SpecificCu Labeling of the Serine Protease, Active Site Inhibited Factor Seven Azide (FVIIai-N), Using Copper Free Click Chemistry

    DEFF Research Database (Denmark)

    Jeppesen, Troels E; Kristensen, Lotte K; Nielsen, Carsten H

    2018-01-01

    A method for site-specific radiolabeling of the serine protease active site inhibited factor seven (FVIIai) with64Cu has been applied using a biorthogonal click reaction. FVIIai binds to tissue factor (TF), a trans-membrane protein involved in hemostasis, angiogenesis, proliferation, cell migrati...

  13. Nano-sized metabolic precursors for heterogeneous tumor-targeting strategy using bioorthogonal click chemistry in vivo.

    Science.gov (United States)

    Lee, Sangmin; Jung, Seulhee; Koo, Heebeom; Na, Jin Hee; Yoon, Hong Yeol; Shim, Man Kyu; Park, Jooho; Kim, Jong-Ho; Lee, Seulki; Pomper, Martin G; Kwon, Ick Chan; Ahn, Cheol-Hee; Kim, Kwangmeyung

    2017-12-01

    Herein, we developed nano-sized metabolic precursors (Nano-MPs) for new tumor-targeting strategy to overcome the intrinsic limitations of biological ligands such as the limited number of biological receptors and the heterogeneity in tumor tissues. We conjugated the azide group-containing metabolic precursors, triacetylated N-azidoacetyl-d-mannosamine to generation 4 poly(amidoamine) dendrimer backbone. The nano-sized dendrimer of Nano-MPs could generate azide groups on the surface of tumor cells homogeneously regardless of cell types via metabolic glycoengineering. Importantly, these exogenously generated 'artificial chemical receptors' containing azide groups could be used for bioorthogonal click chemistry, regardless of phenotypes of different tumor cells. Furthermore, in tumor-bearing mice models, Nano-MPs could be mainly localized at the target tumor tissues by the enhanced permeation and retention (EPR) effect, and they successfully generated azide groups on tumor cells in vivo after an intravenous injection. Finally, we showed that these azide groups on tumor tissues could be used as 'artificial chemical receptors' that were conjugated to bioorthogonal chemical group-containing liposomes via in vivo click chemistry in heterogeneous tumor-bearing mice. Therefore, overall results demonstrated that our nano-sized metabolic precursors could be extensively applied to new alternative tumor-targeting technique for molecular imaging and drug delivery system, regardless of the phenotype of heterogeneous tumor cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Super-resolution optical DNA Mapping via DNA methyltransferase-directed click chemistry

    DEFF Research Database (Denmark)

    Vranken, Charlotte; Deen, Jochem; Dirix, Lieve

    2014-01-01

    We demonstrate an approach to optical DNA mapping, which enables near single-molecule characterization of whole bacteriophage genomes. Our approach uses a DNA methyltransferase enzyme to target labelling to specific sites and copper-catalysed azide-alkyne cycloaddition to couple a fluorophore...... to the DNA. We achieve a labelling efficiency of ∼70% with an average labelling density approaching one site every 500 bp. Such labelling density bridges the gap between the output of a typical DNA sequencing experiment and the long-range information derived from traditional optical DNA mapping. We lay...... the foundations for a wider-scale adoption of DNA mapping by screening 11 methyltransferases for their ability to direct sequence-specific DNA transalkylation; the first step of the DNA labelling process and by optimizing reaction conditions for fluorophore coupling via a click reaction. Three of 11 enzymes...

  15. Alkyne- and 1,6-elimination- succinimidyl carbonate – terminated heterobifunctional poly(ethylene glycol) for reversible "Click" PEGylation

    OpenAIRE

    Xie, Yumei; Duan, Shaofeng; Forrest, M. Laird

    2010-01-01

    A new heterobifunctional (succinimidyl carbonate, SC)-activated poly(ethylene glycol) (PEG) with a reversible 1,6-elimination linker and a terminal alkyne for "click" chemistry was synthesized with high efficiency and low polydispersity. The α-alkyne-ω-hydroxyl PEG was first prepared using trimethylsilyl-2-propargyl alcohol as an initiator for ring-opening polymerization of ethylene oxide followed by mild deprotection with tetrabutylammonium fluoride. The hydroxy end was then modified with di...

  16. Detecting Source Code Plagiarism on .NET Programming Languages using Low-level Representation and Adaptive Local Alignment

    Directory of Open Access Journals (Sweden)

    Oscar Karnalim

    2017-01-01

    Full Text Available Even though there are various source code plagiarism detection approaches, only a few works which are focused on low-level representation for deducting similarity. Most of them are only focused on lexical token sequence extracted from source code. In our point of view, low-level representation is more beneficial than lexical token since its form is more compact than the source code itself. It only considers semantic-preserving instructions and ignores many source code delimiter tokens. This paper proposes a source code plagiarism detection which rely on low-level representation. For a case study, we focus our work on .NET programming languages with Common Intermediate Language as its low-level representation. In addition, we also incorporate Adaptive Local Alignment for detecting similarity. According to Lim et al, this algorithm outperforms code similarity state-of-the-art algorithm (i.e. Greedy String Tiling in term of effectiveness. According to our evaluation which involves various plagiarism attacks, our approach is more effective and efficient when compared with standard lexical-token approach.

  17. Synthesis of Upconverting Hydrogel Nanocomposites Using Thiol-Ene Click Chemistry: Template for the Formation of Dendrimer-Like Gold Nanoparticle Assemblies.

    Science.gov (United States)

    Meesaragandla, Brahmaiah; Mahalingam, Venkataramanan

    2015-11-16

    The synthesis of upconverting hydrogel nanocomposites by base-catalyzed thiol-ene click reaction between 10-undecenoic acid capped Yb(3+)/Er(3+)-doped NaYF4 nanoparticles and pentaerythritol tetrakis(3-mercaptopropionate) (PETMP) as tetrathiol monomer is reported. This synthetic strategy for nanocomposite gels is quite different from works where usually the preformed gels are mixed with the nanoparticles. Developing nanocomposites by surface modification of capping ligands would allow tuning and controlling of the separation of the nanoparticles inside the gel network. The hydrogel nanocomposites prepared by thiol-ene click reaction show strong enhancement in luminescence intensity compared to 10-undecenoic acid-capped Yb(3+)/Er(3+)-doped NaYF4 nanoparticles through the upconversion process (under 980 nm laser excitation). The hydrogel nanocomposites display strong swelling characteristics in water resulting in porous structures. Interestingly, the resulting nanocomposite gels act as templates for the synthesis of dendrimer-like Au nanostructures when HAuCl4 is reduced in the presence of the nanocomposite gels. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Determination of activation level energy of nuclear isomers by calibration of microspectra of radioactive sources

    International Nuclear Information System (INIS)

    Veres, A.; Pavlicsek, I.

    1980-01-01

    Nuclear isomers with unknown activation level were irradiated by calibrated radioactive sources. The integral cross sections were calculated for different energies of the sources. The activation energy was given by values coinciding with each other within the limits of error. The method made the determination of the unknown level of 1180+-10 keV of 195 Pt nucleus possible. (author)

  19. Ads' click-through rates predicting based on gated recurrent unit neural networks

    Science.gov (United States)

    Chen, Qiaohong; Guo, Zixuan; Dong, Wen; Jin, Lingzi

    2018-05-01

    In order to improve the effect of online advertising and to increase the revenue of advertising, the gated recurrent unit neural networks(GRU) model is used as the ads' click through rates(CTR) predicting. Combined with the characteristics of gated unit structure and the unique of time sequence in data, using BPTT algorithm to train the model. Furthermore, by optimizing the step length algorithm of the gated unit recurrent neural networks, making the model reach optimal point better and faster in less iterative rounds. The experiment results show that the model based on the gated recurrent unit neural networks and its optimization of step length algorithm has the better effect on the ads' CTR predicting, which helps advertisers, media and audience achieve a win-win and mutually beneficial situation in Three-Side Game.

  20. Analysis of Physical, Chemical and Microbiological Pollution in one Right Click

    International Nuclear Information System (INIS)

    Tabet, A.; Khoury, A.

    2011-01-01

    Current researches on the topic of indoor air pollution are moving towards expertise and prevention. Therefore it seems so critical to invest in the area of expertise and create a measuring device performing chemical, physical and bacteriological analysis in one click. Our choice of development towards this system of information management is oriented towards a modular system which can simultaneously transmit on real-time the analysis in the internet. Our production work has used several solutions and analyzed several possible methods such as microprocessor that has shown its reliability. The electronic system worked well even with some problems solved at the level of detection of particles α, β and γ. The solution NO-IP as for the transfer of data over the Internet has been successfully tested. In the same way we have been constrained to achieve measurement campaigns to verify the ability of the device to give consistent values. These campaigns were conducted on the Beaulieu of the University of Rennes 1, given the size of the site; it gives us a fairly comprehensive range of situations. These measurement campaigns extended for several months, with the purpose of comparing and analyzing the various results. These campaigns offer an opportunity of testing the operation of the aircraft and assessing the performance, knowing that all measures were compared to the device certified EN (Gasman). For the development of our device, we specify the direction and scope of the study area, analyze the existing level of detection performed and technical data manipulated, obtain a comprehensive description of the electronic system and reach a reasoned choice of a solution type of development. This allowed us to develop a multifunction prototype which objective is to control the quality of indoor air pollution in habitations. This device admits the same principle as product modem M2M (Machine to Machine). Through processes M2M, machinery (measuring instruments (device) and air

  1. Enhanced Tumor Retention Effect by Click Chemistry for Improved Cancer Immunochemotherapy.

    Science.gov (United States)

    Mei, Ling; Liu, Yayuan; Rao, Jingdong; Tang, Xian; Li, Man; Zhang, Zhirong; He, Qin

    2018-05-30

    Because of the limited drug concentration in tumor tissues and inappropriate treatment strategies, tumor recurrence and metastasis are critical challenges for effectively treating malignancies. A key challenge for effective delivery of nanoparticles is to reduce uptake by reticuloendothelial system and to enhance the permeability and retention effect. Herein, we demonstrated Cu(I)-catalyzed click chemistry triggered the aggregation of azide/alkyne-modified micelles, enhancing micelles accumulation in tumor tissues. In addition, combined doxorubicin with the adjuvant monophosphoryl lipid A, an agonist of toll-like receptor4, generated immunogenic cell death, which further promoted maturity of dendritic cells, antigen presentation and induced strong effector T cells in vivo. Following combined with anti-PD-L1 therapy, substantial antitumor and metastasis inhibitory effects were achieved because of the reduced PD-L1 expression and regulatory T cells. In addition, effective long-term immunity from memory T cell responses protected mice from tumor recurrence.

  2. "Click" chemistry mildly stabilizes bifunctional gold nanoparticles for sensing and catalysis.

    Science.gov (United States)

    Li, Na; Zhao, Pengxiang; Liu, Na; Echeverria, María; Moya, Sergio; Salmon, Lionel; Ruiz, Jaime; Astruc, Didier

    2014-07-01

    A large family of bifunctional 1,2,3-triazole derivatives that contain both a polyethylene glycol (PEG) chain and another functional fragment (e.g., a polymer, dendron, alcohol, carboxylic acid, allyl, fluorescence dye, redox-robust metal complex, or a β-cyclodextrin unit) has been synthesized by facile "click" chemistry and mildly coordinated to nanogold particles, thus providing stable water-soluble gold nanoparticles (AuNPs) in the size range 3.0-11.2 nm with various properties and applications. In particular, the sensing properties of these AuNPs are illustrated through the detection of an analogue of a warfare agent (i.e., sulfur mustard) by means of a fluorescence "turn-on" assay, and the catalytic activity of the smallest triazole-AuNPs (core of 3.0 nm) is excellent for the reduction of 4-nitrophenol in water. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Development of a 60Co radioactive rod source used for γ-ray level gauge

    International Nuclear Information System (INIS)

    Lin Yibing; Pan Liangcai; Yin Shunjiu

    1991-09-01

    The installation of level gauge used for urea stripping tower, the structure and forming of radioactive rod source, and the calculation of its approximate linear graduation are described. The theoretical and practical feasibility has been confirmed from the test results of comparing the imported radioactive rod source to the developed radioactive rod source. The technological process of production, method for obtaining distribution of radioactivity along the axis, and the test and operation of developed rod source on site are also presented

  4. Urban NH3 levels and sources in six major Spanish cities.

    Science.gov (United States)

    Reche, Cristina; Viana, Mar; Karanasiou, Angeliki; Cusack, Michael; Alastuey, Andrés; Artiñano, Begoña; Revuelta, M Aranzazu; López-Mahía, Purificación; Blanco-Heras, Gustavo; Rodríguez, Sergio; Sánchez de la Campa, Ana M; Fernández-Camacho, Rocío; González-Castanedo, Yolanda; Mantilla, Enrique; Tang, Y Sim; Querol, Xavier

    2015-01-01

    A detailed spatial and temporal assessment of urban NH3 levels and potential emission sources was made with passive samplers in six major Spanish cities (Barcelona, Madrid, A Coruña, Huelva, Santa Cruz de Tenerife and Valencia). Measurements were conducted during two different periods (winter-autumn and spring-summer) in each city. Barcelona showed the clearest spatial pattern, with the highest concentrations in the old city centre, an area characterised by a high population density and a dense urban architecture. The variability in NH3 concentrations did not follow a common seasonal pattern across the different cities. The relationship of urban NH3 with SO2 and NOX allowed concluding on the causes responsible for the variations in NH3 levels between measurement periods observed in Barcelona, Huelva and Madrid. However, the factors governing the variations in A Coruña, Valencia and Santa Cruz de Tenerife are still not fully understood. This study identified a broad variability in NH3 concentrations at the city-scale, and it confirms that NH3 sources in Spanish urban environments are vehicular traffic, biological sources (e.g. garbage containers), wastewater treatment plants, solid waste treatment plants and industry. The importance of NH3 monitoring in urban environments relies on its role as a precursor of secondary inorganic species and therefore PMX. Further research should be addressed in order to establish criteria to develop and implement mitigation strategies for cities, and to include urban NH3 sources in the emission inventories. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Stabilization of Parallel Triplexes by Twisted Intercalating Nucleic Acids (TINAs) Incorporating 1,2,3-Triazole Units and Prepared by Microwave-Accelerated Click Chemistry

    DEFF Research Database (Denmark)

    Géci, Imrich; Filitchev, Vyacheslav Viatcheslav; Pedersen, Erik Bjerreg.

    2007-01-01

    A highly efficient method for postsynthetic modification of unprotected oligonucleotides incorporating internal insertions of (R)-1-O-(4-ethynylbenzyl)glycerol has been developed through the application of click chemistry with water-insoluble pyren-1-yl azide and water-soluble benzyl azide and ac...

  6. Artificial Chemical Reporter Targeting Strategy Using Bioorthogonal Click Reaction for Improving Active-Targeting Efficiency of Tumor.

    Science.gov (United States)

    Yoon, Hong Yeol; Shin, Min Lee; Shim, Man Kyu; Lee, Sangmin; Na, Jin Hee; Koo, Heebeom; Lee, Hyukjin; Kim, Jong-Ho; Lee, Kuen Yong; Kim, Kwangmeyung; Kwon, Ick Chan

    2017-05-01

    Biological ligands such as aptamer, antibody, glucose, and peptide have been widely used to bind specific surface molecules or receptors in tumor cells or subcellular structures to improve tumor-targeting efficiency of nanoparticles. However, this active-targeting strategy has limitations for tumor targeting due to inter- and intraheterogeneity of tumors. In this study, we demonstrated an alternative active-targeting strategy using metabolic engineering and bioorthogonal click reaction to improve tumor-targeting efficiency of nanoparticles. We observed that azide-containing chemical reporters were successfully generated onto surface glycans of various tumor cells such as lung cancer (A549), brain cancer (U87), and breast cancer (BT-474, MDA-MB231, MCF-7) via metabolic engineering in vitro. In addition, we compared tumor targeting of artificial azide reporter with bicyclononyne (BCN)-conjugated glycol chitosan nanoparticles (BCN-CNPs) and integrin α v β 3 with cyclic RGD-conjugated CNPs (cRGD-CNPs) in vitro and in vivo. Fluorescence intensity of azide-reporter-targeted BCN-CNPs in tumor tissues was 1.6-fold higher and with a more uniform distribution compared to that of cRGD-CNPs. Moreover, even in the isolated heterogeneous U87 cells, BCN-CNPs could bind artificial azide reporters on tumor cells more uniformly (∼92.9%) compared to cRGD-CNPs. Therefore, the artificial azide-reporter-targeting strategy can be utilized for targeting heterogeneous tumor cells via bioorthogonal click reaction and may provide an alternative method of tumor targeting for further investigation in cancer therapy.

  7. Significant variations in Weber fraction for changes in inter-onset interval of a click train over the range of intervals between 5 and 300 ms.

    Science.gov (United States)

    Ungan, Pekcan; Yagcioglu, Suha

    2014-01-01

    It is a common psychophysical experience that a train of clicks faster than ca. 30/s is heard as one steady sound, whereas temporal patterns occurring on a slower time scale are perceptually resolved as individual auditory events. This phenomenon suggests the existence of two different neural mechanisms for processing of auditory sequences with fast and slow repetition rates. To test this hypothesis we used Weber's law, which is known to be valid for perception of time intervals. Discrimination thresholds and Weber fractions (WFs) for 12 base inter-click intervals (ICIs) between 5 and 300 ms were measured from 10 normal hearing subjects by using an "up-down staircase" algorithm. The mean WF, which is supposed to be constant for any perceptual mechanism according to Weber's law, displayed significant variation with click rate. WFs decreased sharply from an average value of around 5% at repetition rates below 20 Hz to about 0.5% at rates above 67 Hz. Parallel to this steep transition, subjects reported that at rates below 20 Hz they perceived periodicity as a fast tapping rhythm, whereas at rates above 50 Hz the perceived quality was a pitch. Such a dramatic change in WF indicated the existence of two separate mechanisms for processing the click rate for long and short ICIs, based on temporal and spectral features, respectively. A range of rates between 20 and 33 Hz, in which the rate discrimination threshold was maximum, appears to be a region where both of the presumed time and pitch mechanisms are relatively insensitive to rate alterations. Based on this finding, we speculate that the interval-based perception mechanism ceases to function at around 20 Hz and the spectrum-based mechanism takes over at around 33 Hz; leaving a transitional gap in between, where neither of the two mechanisms is as sensitive. Another notable finding was a significant drop in WF for ICI = 100 ms, suggesting a connection of time perception to the electroencephalography alpha rhythm.

  8. Redox-responsive core cross-linked prodrug micelles prepared by click chemistry for pH-triggered doxorubicin delivery

    Directory of Open Access Journals (Sweden)

    X. T. Cao

    2017-10-01

    Full Text Available A pH-triggered drug delivery system of degradable core cross-linked (CCL prodrug micelles was prepared by click chemistry. Doxorubicin conjugated block copolymers of azido functional poly(ethylene oxide-b-poly(glycidyl methacrylate were synthesized by the combination of RAFT polymerization, epoxide ring-opening reaction, and acid-cleavable hydrazone linkages. The CCL prodrug micelles were produced by the reaction of dipropargyl 3,3′-dithiodipropionate and dipropargyl adipate cross-linking agents with the azido groups of the micellar core via alkyne-azide click reaction, which were denoted as CCL/SS and CCL/noSS, respectively. The TEM images of CCL/SS prodrug micelles showed a spherical shape with the average diameter of 61.0 nm from water, and the shape was maintained with an increased diameter upon dilution with 5-fold DMF. The high DOX conjugation efficiency was 88.4%. In contrast to a very slow DOX release from CCL/SS prodrug micelles under the physiological condition (pH 7.4, the drug release is much faster (90% at pH 5.0 and 10 mM of GSH after 96 h. The cytotoxicity test and confocal laser scanning microscopy analysis revealed that CCL/SS prodrug micelles had much enhanced intracellular drug release capability in HepG2 cells than CCL/noSS prodrug micelles.

  9. Offshore dredger sound: source levels, sound maps and risk assessment (abstract)

    NARCIS (Netherlands)

    Jong, C.A.F. de; Ainslie, M.A.; Heinis, F.; Janmaat, J.

    2013-01-01

    The Port of Rotterdam is expanding to meet the growing demand to accommodate large cargo vessels. One of the licensing conditions was the monitoring of the underwater sound produced during its construction, with an emphasis on the establishment of acoustic source levels of the Trailing Suction

  10. Evaluating distance-based clustering for user (browse and click) sessions in a domain-specific collection

    DEFF Research Database (Denmark)

    Steinhauer, Jeremy; Delcambre, Lois M.L.; Lykke, Marianne

    2014-01-01

    to the question that they are answering. Since a large class of machine learning algorithms use a distance measure at the core, we evaluate the suitability of common machine learning distance measures to distinguish sessions of users searching for the answer to same or different questions. We found that two......We seek to improve information retrieval in a domain-specific collection by clustering user sessions from a click log and then classifying later user sessions in real time. As a preliminary step, we explore the main assumption of this approach: whether user sessions in such a site are related...

  11. Space Vector Pulse Width Modulation Strategy for Single-Phase Three-Level CIC T-source Inverter

    DEFF Research Database (Denmark)

    Shults, Tatiana E.; Husev, Oleksandr O.; Blaabjerg, Frede

    2016-01-01

    This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance of the inver......This paper presents a novel space vector pulse-width modulation strategy for a single-phase three-level buck-boost inverter based on an impedance-source network. The case study system is based on T-source inverter with continuous input current. To demonstrate the improved performance...... of the inverter, the strategy was compared the traditional pulse-width modulation. It is shown that the approach proposed has fewer switching states and does not suffer from neutral point misbalance....

  12. Sources and levels of concentration of metal pollutants in Kubanni dam, Zaria, Nigeria

    Directory of Open Access Journals (Sweden)

    Butu, A.W.

    2013-06-01

    Full Text Available The paper looked at the sources and levels of concentration of metal pollutants in Kubanni dam, Zaria, Nigeria. The main sources of data for the study were sediment from four different sections of the long profile of the dam. The samples were prepared in the laboratory according to standard methods and the instrumental Neutron Activation Analysis (INAA technique was adopted in the analysis using Nigeria Research Reactor – 1 (NIRR – 1. The results of the analysis showed that 29 metal pollutants; Mg, Al, Ca, Ti, V, Mn, Dy, Na, K, As, La, Sm, Yb, U, Br, Sc, Cr, Fe, Co, Rb, Zn,Cs, Ba, Eu, Lu, Hf, Ta, Sb and Th currently exist in Kubanni dam in various levels of concentrations. The results showed that most of the metal pollutants in the dam are routed to anthropogenic activities within the dam catchment area while few are routed to geologic formation. The results further revealed that metal pollutants that their sources are traceable to refuse dumps, farmlands, public drains and effluents showed higher levels of concentration in the dam than the ones that are gradually released from the soil regolith system.

  13. Sources, production rates and characteristics of ERDA low-level wastes

    International Nuclear Information System (INIS)

    Dieckhoner, J.E.

    1979-01-01

    In recent critical reviews of the long-standing practice of disposing of solid non-high-level radioactive waste by shallow earth burial, one recurring identified need was for better source-term information. As the major employer of this particular radioactive waste management technique for the past 30 years, ERDA recognizes the value of this type of information and has systematically collected it. The system used by the AEC and ERDA in the past was admittedly cumbersome, so in FY 1976 an improved, automated information management system was developed. This new system, called SWIMS (Solid Waste Information Management System), was designed to replace the older system and accept more detailed information from all ERDA solid, non-high-level radioactive waste generation, retrievable storage and shallow land burial activities. In FY 1977, SWIMS is in a trial phase in which modifications and clarifications are being made. In FY 1978, it will be fully operational. This paper presents data concerning the sources and characteristics of waste generated by ERDA facilities. Information on the cumulative status of ERDA's waste is presented, along with a comparison of the types of data collected under the old system and the new system

  14. Indoor NO{sub 2} levels in homes with different sources of air pollution - traffic, gas-use, smoking

    Energy Technology Data Exchange (ETDEWEB)

    Rudnai, P.; Farkas, I.; Bacskai, J.; Sarkany, E. [Bela Johan National Inst. of Hygiene, Budapest (Hungary); Somogyi, J. [Public Health Inst. of County Gyor-Moson-Sopron, Gyor (Hungary)

    1993-12-31

    Outdoor and indoor levels of NO{sub 2} in and around the homes of 300 children living in different parts of two Hungarian towns, Gyor and Sopron, were measured. Possible sources of NO{sub 2} pollution were assessed by questionnaires. NO{sub 2} levels in homes without any further known sources (like gas use for cooking and/or heating and smoking) varied according to the outdoor levels mainly depending on traffic density. Gas heaters had the strongest influence on the indoor NO{sub 2} levels measured in the children`s bedrooms while gas use for cooking and smoking proved to be the second and third most important source of indoor NO{sub 2} pollution. Different outdoor and indoor NO{sub 2} sources should be taken into account when planning the heating and ventilation systems of new buildings. (author)

  15. Glucose becomes one of the worst carbon sources for E.coli on poor nitrogen sources due to suboptimal levels of cAMP

    Science.gov (United States)

    Bren, Anat; Park, Junyoung O.; Towbin, Benjamin D.; Dekel, Erez; Rabinowitz, Joshua D.; Alon, Uri

    2016-01-01

    In most conditions, glucose is the best carbon source for E. coli: it provides faster growth than other sugars, and is consumed first in sugar mixtures. Here we identify conditions in which E. coli strains grow slower on glucose than on other sugars, namely when a single amino acid (arginine, glutamate, or proline) is the sole nitrogen source. In sugar mixtures with these nitrogen sources, E. coli still consumes glucose first, but grows faster rather than slower after exhausting glucose, generating a reversed diauxic shift. We trace this counterintuitive behavior to a metabolic imbalance: levels of TCA-cycle metabolites including α-ketoglutarate are high, and levels of the key regulatory molecule cAMP are low. Growth rates were increased by experimentally increasing cAMP levels, either by adding external cAMP, by genetically perturbing the cAMP circuit or by inhibition of glucose uptake. Thus, the cAMP control circuitry seems to have a ‘bug’ that leads to slow growth under what may be an environmentally rare condition. PMID:27109914

  16. Role Pay-per-Click internetové reklamní kampaně v marketingových aktivitách firmy

    OpenAIRE

    Černý, Jakub

    2009-01-01

    This paper is focused on analysis of internet advertising and its role in marketing communication. The paper determines general methods and instruments of internet marketing and describes internet advertisement in comparison with traditional advertising media. In more detail the paper is focused on description and explanation of effect of Pay-Per-Click advertisement campaigns. The options of their usage and recognized differences are explicated by practical instance of marketing strategies of...

  17. Lignin-Based Materials Through Thiol-Maleimide "Click" Polymerization.

    Science.gov (United States)

    Buono, Pietro; Duval, Antoine; Averous, Luc; Habibi, Youssef

    2017-03-09

    In the present report an environmentally friendly approach to transforming renewable feedstocks into value-added materials is proposed. This transformation pathway was conducted under green conditions, without the use of solvents or catalyst. First, controlled modification of lignin, a major biopolymer present in wood and plants, was achieved by esterification with 11-maleimidoundecylenic acid (11-MUA), a derivative from castor oil that contains maleimide groups, following its transformation into 11-maleimidoundecanoyl chloride (11-MUC). Different degrees of substitution were achieved by using various amounts of the 11-MUC, leading to an efficient conversion of lignin hydroxy groups, as demonstrated by 1 H and 31 P NMR analyses. These fully biobased maleimide-lignin derivatives were subjected to an extremely fast (ca. 1 min) thiol-ene "click" polymerization with thiol-containing linkers. Aliphatic and aromatic thiol linkers bearing two to four thiol groups were used to tune the reactivity and crosslink density. The properties of the resulting materials were evaluated by swelling tests and thermal and mechanical analyses, which showed that varying the degree of functionality of the linker and the linker structure allowed accurate tailoring of the thermal and mechanical properties of the final materials, thus providing interesting perspectives for lignin in functional aromatic polymers. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Synthesis of amphiphilic aminated inulin via 'click chemistry' and evaluation for its antibacterial activity.

    Science.gov (United States)

    Dong, Fang; Zhang, Jun; Yu, Chunwei; Li, Qing; Ren, Jianming; Wang, Gang; Gu, Guodong; Guo, Zhanyong

    2014-09-15

    Inulins are a group of abundant, water-soluble, renewable polysaccharides, which exhibit attractive bioactivities and natural properties. Improvement such as chemical modification of inulin is often performed prior to further utilization. We hereby presented a method to modify inulin at its primary hydroxyls to synthesize amphiphilic aminated inulin via 'click chemistry' to facilitate its chemical manipulation. Additionally, its antibacterial property against Staphylococcus aureus (S. aureus) was also evaluated and the best inhibitory index against S. aureus was 58% at 1mg/mL. As the amphiphilic aminated inulin is easy to prepare and exhibits improved bioactivity, this material may represent as an attractive new platform for chemical modifications of inulin. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Significant variations in Weber fraction for changes in inter-onset interval of a click train over the range of intervals between 5 ms and 300 ms

    Directory of Open Access Journals (Sweden)

    Pekcan eUngan

    2014-12-01

    Full Text Available It is a common psychophysical experience that a train of clicks faster than ca. 30 per second is heard as one steady sound, whereas temporal patterns occurring on a slower time scale are perceptually resolved as individual auditory events. This phenomenon suggests the existence of two different neural mechanisms for processing of auditory sequences with fast and slow repetition rates. To test this hypothesis we used Weber’s law, which is known to be valid for perception of time intervals. Discrimination thresholds and Weber fractions (WF for twelve base inter-click intervals (ICI between 5 ms and 300 ms were measured from ten normal hearing subjects by using an up-down staircase algorithm. The mean WF, which is supposed to be constant for any perceptual mechanism according to Weber’s law, displayed significant variation with click rate. WFs decreased sharply from an average value of around 5% at repetition rates below 20 Hz to about 0.5% at rates above 67 Hz. Parallel to this steep transition, subjects reported that at rates below 20 Hz they perceived periodicity as a fast tapping rhythm, whereas at rates above 50 Hz the perceived quality was a pitch. Such a dramatic change in WF indicated the existence of two separate mechanisms for processing the click rate for long and short ICIs, based on temporal and spectral features, respectively. A range of rates between 20 Hz and 33 Hz, in which the rate discrimination threshold was maximum, appears to be a region where both of the presumed time and pitch mechanisms are relatively insensitive to rate alterations. Based on this finding, we speculate that the interval-based perception mechanism ceases to function at around 20 Hz and the spectrum-based mechanism takes over at around 33 Hz; leaving a transitional gap in between, where neither of the two mechanisms is as sensitive. Another notable finding was a significant drop in WF for ICI=100 ms, suggesting a connection of time perception to the EEG

  20. Experimental study on source efficiencies for estimating surface contamination level

    International Nuclear Information System (INIS)

    Ichiji, Takeshi; Ogino, Haruyuki

    2008-01-01

    Source efficiency was measured experimentally for various materials, such as metals, nonmetals, flooring materials, sheet materials and other materials, contaminated by alpha and beta emitter radioactive nuclides. Five nuclides, 147 Pm, 60 Co, 137 Cs, 204 Tl and 90 Sr- 90 Y, were used as the beta emitters, and one nuclide 241 Am was used as the alpha emitter. The test samples were prepared by placing drops of the radioactive standardized solutions uniformly on the various materials using an automatic quantitative dispenser system from Musashi Engineering, Inc. After placing drops of the radioactive standardized solutions, the test materials were allowed to dry for more than 12 hours in a draft chamber with a hood. The radioactivity of each test material was about 30 Bq. Beta rays or alpha rays from the test materials were measured with a 2-pi gas flow proportional counter from Aloka Co., Ltd. The source efficiencies of the metals, nonmetals and sheet materials were higher than 0.5 in the case of contamination by the 137 Cs, 204 Tl and 90 Sr- 90 Y radioactive standardized solutions, higher than 0.4 in the case of contamination by the 60 Co radioactive standardized solution, and higher than 0.25 in the case of contamination by the alpha emitter the 241 Am radioactive standardized solution. These values were higher than those given in Japanese Industrial Standards (JIS) documents. In contrast, the source efficiencies of some permeable materials were lower than those given in JIS documents, because source efficiency varies depending on whether the materials or radioactive sources are wet or dry. This study provides basic data on source efficiency, which is useful for estimating the surface contamination level of materials. (author)

  1. Climatic, Edaphic Factors and Cropping History Help Predict Click Beetle (Coleoptera: Elateridae) (Agriotes spp.) Abundance.

    Science.gov (United States)

    Kozina, A; Lemic, D; Bazok, R; Mikac, K M; Mclean, C M; Ivezić, M; Igrc Barčić, J

    2015-01-01

    It is assumed that the abundance of Agriotes wireworms (Coleoptera: Elateridae) is affected by agro-ecological factors such as climatic and edaphic factors and the crop/previous crop grown at the sites investigated. The aim of this study, conducted in three different geographic counties in Croatia from 2007 to 2009, was to determine the factors that influence the abundance of adult click beetle of the species Agriotes brevis Cand., Agriotes lineatus (L.), Agriotes obscurus (L.), Agriotes sputator (L.), and Agriotes ustulatus Schall. The mean annual air temperature, total rainfall, percentage of coarse and fine sand, coarse and fine silt and clay, the soil pH, and humus were investigated as potential factors that may influence abundance. Adult click beetle emergence was monitored using sex pheromone traps (YATLORf and VARb3). Exploratory data analysis was preformed via regression tree models and regional differences in Agriotes species' abundance were predicted based on the agro-ecological factors measured. It was found that the best overall predictor of A. brevis abundance was the previous crop grown. Conversely, the best predictor of A. lineatus abundance was the current crop being grown and the percentage of humus. The best predictor of A. obscurus abundance was soil pH in KCl. The best predictor of A. sputator abundance was rainfall. Finally, the best predictors of A. ustulatus abundance were soil pH in KCl and humus. These results may be useful in regional pest control programs or for predicting future outbreaks of these species. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  2. Determination of Noise Level and Its Sources in the Neonatal Intensive Care Unit and Neonatal Ward

    Directory of Open Access Journals (Sweden)

    Mahdi Jahangir Blourchian

    2015-12-01

    Full Text Available Background: In Neonatal intensive care units (NICU different sound intensities and frequencies are produced from different sources, which may exert undesirable physiological effects on the infants. The aim of this study was to determine the noise level and its sources in the NICU and neonatal ward of Al-Zahra Hospital of Rasht, Iran. Methods: In this descriptive cross-sectional study, the intensity of the sounds generated by the internal and external sources in the NICU and neonatal ward was measured using a sound level meter device. The sound produced by each of the sources was individually calculated. Data were analyzed performing descriptive and analytical statistics, using SPSS version 19. Results: The mean noise levels in six rooms and a hallway during morning, afternoon and night shifts with the electromechanical devices turned on were 61.67±4.5, 61.32±4.32 and 60.71±4.56 dB, respectively. Moreover, with the devices tuned off the mean noise levels during morning, afternoon and evening shifts were 64.97±2.6, 60.6±1.29 and 57.91±4.73 dB, respectively. The differences between the mean noise levels in the neonatal wards (standard noise level=45 dB during each shift with the electromechanical devices turned on and off were statistically significant (P=0.002 and P

  3. Look! It's Rock'n'roll!

    DEFF Research Database (Denmark)

    Lindelof, Anja

    2007-01-01

    , and dates. Consult your library or click here for more information on citing sources. -------------------------------------------------------------------------------- Anja Mølle Lindelof. (2007). Look! it's rock'n'roll! how television participated in shaping the visual genre conventions of popular music...... to personal names, capitalization, and dates. Consult your library or click here for more information on citing sources. -------------------------------------------------------------------------------- Anja Mølle Lindelof. "Look! It's Rock'n'roll! How television participated in shaping the visual genre....... Pay special attention to personal names, capitalization, and dates. Consult your library or click here for more information on citing sources. -------------------------------------------------------------------------------- TY - JOUR T1 - Look! It's Rock'n'roll! How television participated in shaping...

  4. Novel Anti-Biofouling Soft Contact Lens: l-Cysteine Conjugated Amphiphilic Conetworks via RAFT and Thiol-Ene Click Chemistry.

    Science.gov (United States)

    Zhang, Chengfeng; Liu, Ziyuan; Wang, Haiye; Feng, Xiaofeng; He, Chunju

    2017-07-01

    A unique l-cysteine conjugated antifouling amphiphilic conetwork (APCN) is synthesized through end-crosslinking of well-defined triblock copolymers poly(allyl methacrylate)-b-poly(ethylene glycol)-b-poly(allyl methacrylate) via a combination of reversible addition-fragmentation chain transfer (RAFT) polymerization and thiol-ene "click" chemistry. The synthesized poly(ethylene glycol) macro-RAFT agent initiates the polymerization of allyl methacrylate in a controlled manner. The vinyl pendant groups of the precursor partially conjugate with l-cysteine and the rest fully crosslink with mercaptopropyl-containing siloxane via thiol-ene click chemistry under UV irradiation into APCNs, which show distinguished properties, that is, excellent biocompatibility, more than 39.6% water content, 101 barrers oxygen permeability, optimized mechanical properties, and more than 93% visible light transmittance. What's more, the resultant APCNs exhibit eminent resistance to protein adsorption, where the bovine serum albumin and lysozyme adsorption are decreased to 12 and 21 µg cm -2 , respectively. The outstanding properties of APCNs depend on the RAFT controlled method, which precisely designs the hydrophilic/hydrophobic segments and eventually greatly improves the crosslinking efficiency and homogeneity. Meantime, the l-cysteine monolayer can effectively reduce the surface hydrophobicity and prevent protein adsorption, which exhibits the viability for antifouling surface over and under ophthalmic devices, suggesting a promising soft contact lens. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Alternative high-level radiation sources for sewage and waste-water treatment

    International Nuclear Information System (INIS)

    Ballantine, D.S.

    1975-01-01

    The choice of an energy source for the radiation treatment of waste-water or sludge is between an electron accelerator or a gamma-ray source of radioactive cobalt or caesium. A number of factors will affect the ultimate choice and the potential future adoption of radiation as a treatment technique. The present and future availability of radioactive sources of cobalt and caesium is closely linked to the rate of nuclear power development and the assumption by uranium fuel reprocessors of a role as radioactive caesium suppliers. Accelerators are industrial machines which could be readily produced to meet any conceivable market demand. For energy sources in the 20-30 kW range, electron accelerators appear to have an initial capital cost advantage of about seven and an operating cost advantage of two. While radioisotope sources are inherently more reliable, accelerators at voltages to 3 MeV have achieved a reliability level adequate to meet the demands of essentially continuous operations with moderate maintenance requirements. The application of either energy source to waste-water treatment will be significantly influenced by considerations of the relative penetration capability, energy density and physical geometrical constraints of each option. The greater range of the gamma rays and the lower energy density of the isotopic sources permit irradiation of a variety of target geometrics. The low penetration of electrons and the high-energy density of accelerators limit application of the latter to targets presented as thin films of several centimetres thickness. Any potential use of radiation must proceed from a clear definition of process objectives and critical comparison of the radiation energy options for that specific objective. (Author)

  6. Storage of low-level radioactive waste and regulatory control of sealed sources in Finland

    International Nuclear Information System (INIS)

    Rahola, T.; Markkanen, M.

    2006-01-01

    This paper is concentrated on the non nuclear low-level radioactive waste. The cornerstone for maintaining radioactive sources under control in Finland is that all practices involving sources are subject to authorization and all licensing information, including information on each individual source, are entered into a register which is continuously updated based on applications and notifications received from the licenses. Experiences during the past twenty years have shown that source-specific records of sources combined with regular inspections at the places of use have prevented efficiency losing control over sealed radioactive sources. The current capacity in the interim storage for State owned waste is not adequate for all used sealed sources and other small user waste which are currently kept in the possession of the licensees. Thus, expansion of the storage capacity and other options for taking care of the small user waste is under consideration. (N.C.)

  7. Lead in game birds in Denmark - levels and sources

    DEFF Research Database (Denmark)

    Kanstrup, Niels

    2012-01-01

    In June 2008, the National Food Agency contacted Bjarne Frost Vildt against the background that the Danish surveillance of heavy metals in food (EU Directive 96/23 of 29 April 1996) had, for several years, shown elevated lead levels in game meat. These elevated levels exceeded the official...... project to identify the source of lead in game meat. In July 2008, the Danish Academy of Hunting was tasked to design and carry out the investigation, in cooperation with the Veterinary Institute (Technical University of Denmark) and Food Region North (Ministry of Food, Agriculture and Fisheries....../2009 and 2009/2010 may be driven by three The biggest Danish butchery for game meat different reasons: reduced illegal use of lead shot due to the campaign initiated in 2008; reduced concentration of lead in bismuth shot (2009/2010) due to the conclusions of this study; and/or reluctance to deliver pheasants...

  8. Click chemistry on the surface of PLGA-b-PEG polymeric nanoparticles: a novel targetable fluorescent imaging nanocarrier

    Energy Technology Data Exchange (ETDEWEB)

    Pucci, Andrea; Locatelli, Erica [University of Bologna, Dipartimento di Chimica Industriale ' Toso Montanari' (Italy); Ponti, Jessica; Uboldi, Chiara [Institute for Health and Consumer Protection, Joint Research Centre, Nanobiosciences Unit (Italy); Molinari, Valerio; Comes Franchini, Mauro, E-mail: mauro.comesfranchini@unibo.it [University of Bologna, Dipartimento di Chimica Industriale ' Toso Montanari' (Italy)

    2013-08-15

    In the quest for biocompatible nanocarriers for biomedical applications, a great deal of effort is put on engineering the nanocomposites surface in order to render them specific to the particular purpose. We developed biocompatible PLGA-b-PEG-based nanoparticles carrying a double functionality (i.e., carboxylic and acetylenic) able to serve as flexible highly selective grafting centers for cancer diagnosis and treatment. As a proof of concept, the nanocarrier was successfully functionalized with a tailored fluorescent molecule by means of click chemistry and with a targeting agent specific for glioblastoma multiforme via amidic bond formation.

  9. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.; Rodionov, Valentin; Kü hn, Fritz; Reiser, Oliver

    2012-01-01

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient

  10. Synthesis of Dendrimer Containing Dialkylated-fluorene Unit as a Core Chromophore via Click Chemistry

    International Nuclear Information System (INIS)

    Han, Seung Choul; Lee, Jae Wook; Jin, Sung Ho

    2012-01-01

    The convergent synthetic strategy for the emissive dendrimers having the chromophore at core via the coppercatalyzed 1,3-dipolar cycloaddition reaction between alkyne and azide was described. 2,7-Diazido-9,9-dioctyl- 9H-fluorene, designed to serve as the core in dendrimer, was stitched with the alkyne-functionalized Frechettype and PAMAM dendrons by the click chemistry leading to the formation of the corresponding fluorescent dendrimers in high yields. The preliminary photoluminescence studies indicated that 2,7-diazido-9,9-dioctyl- 9H-fluorene showed no fluorescence due to the quenching effect from the electron-rich α-nitrogen of the azido group but the dendrimers fluoresced due to the elimination of the quenching through the formation of the triazole ring

  11. Low fouling polysulfone ultrafiltration membrane via click chemistry

    KAUST Repository

    Xie, Yihui

    2014-10-13

    Hydrophilic surfaces are known to be less prone to fouling. Ultrafiltration membranes are frequently prepared from rather hydrophobic polymers like polysulfone (PSU). Strategies to keep the good pore forming characteristics of PSU, but with improved hydrophilicity are proposed here. PSU functionalized with 1,2,3-triazole ring substituents containing OH groups was successfully synthesized through click chemistry reaction. The structures of the polymers were confirmed using NMR spectroscopy and Fourier transform infrared spectroscopy (FTIR). High thermal stability (>280°C) was observed by thermal gravimetric analysis. Elemental analysis showed the presence of nitrogen containing triazole group with different degrees of functionalization (23%, 49%, 56%, and 94%). The glass transition temperature shifted with the introduction of triazole pendant groups from 190°C (unmodified) to 171°C. Ultrafiltration membranes were prepared via phase inversion by immersion in different coagulation baths (NMP/water mixtures with volume ratios from 0/100 to 40/60). The morphologies of these membranes were studied by field emission scanning electron microscopy (FESEM). The optimized PSU bearing triazole functions membranes exhibited water permeability up to 187 L m-2 h-1 bar-1, which is 23 times higher than those prepared under the same conditions but with unmodified polysulfone (PSU; 8 L m-2 h-1 bar-1). Results of bovine serum albumin protein rejection test indicated that susceptibility to fouling decreased with the modification, due to the increased hydrophilicity, while keeping high protein rejection ratio (>99%).

  12. Click strategies for single-molecule protein fluorescence.

    Science.gov (United States)

    Milles, Sigrid; Tyagi, Swati; Banterle, Niccolò; Koehler, Christine; VanDelinder, Virginia; Plass, Tilman; Neal, Adrian P; Lemke, Edward A

    2012-03-21

    Single-molecule methods have matured into central tools for studies in biology. Foerster resonance energy transfer (FRET) techniques, in particular, have been widely applied to study biomolecular structure and dynamics. The major bottleneck for a facile and general application of these studies arises from the need to label biological samples site-specifically with suitable fluorescent dyes. In this work, we present an optimized strategy combining click chemistry and the genetic encoding of unnatural amino acids (UAAs) to overcome this limitation for proteins. We performed a systematic study with a variety of clickable UAAs and explored their potential for high-resolution single-molecule FRET (smFRET). We determined all parameters that are essential for successful single-molecule studies, such as accessibility of the probes, expression yield of proteins, and quantitative labeling. Our multiparameter fluorescence analysis allowed us to gain new insights into the effects and photophysical properties of fluorescent dyes linked to various UAAs for smFRET measurements. This led us to determine that, from the extended tool set that we now present, genetically encoding propargyllysine has major advantages for state-of-the-art measurements compared to other UAAs. Using this optimized system, we present a biocompatible one-step dual-labeling strategy of the regulatory protein RanBP3 with full labeling position freedom. Our technique allowed us then to determine that the region encompassing two FxFG repeat sequences adopts a disordered but collapsed state. RanBP3 serves here as a prototypical protein that, due to its multiple cysteines, size, and partially disordered structure, is not readily accessible to any of the typical structure determination techniques such as smFRET, NMR, and X-ray crystallography.

  13. Diffusion of dust particles from a point-source above ground level

    International Nuclear Information System (INIS)

    Hassan, M.H.A.; Eltayeb, I.A.

    1998-10-01

    A pollutant of small particles is emitted by a point source at a height h above ground level in an atmosphere in which a uni-directional wind speed, U, is prevailing. The pollutant is subjected to diffusion in all directions in the presence of advection and settling due to gravity. The equation governing the concentration of the pollutant is studied with the wind speed and the different components of diffusion tensor are proportional to the distance above ground level and the source has a uniform strength. Adopting a Cartesian system of coordinates in which the x-axis lies along the direction of the wind velocity, the z-axis is vertically upwards and the y-axis completes the right-hand triad, the solution for the concentration c(x,y,z) is obtained in closed form. The relative importance of the components of diffusion along the three axes is discussed. It is found that for any plane y=constant (=A), c(x,y,z) is concentrated along a curve of ''extensive pollution''. In the plane A=0, the concentration decreases along the line of extensive pollution as we move away from the source. However, for planes A≅0, the line of extensive pollution possesses a point of accumulation, which lies at a nonzero value of x. As we move away from the plane A=0, the point of accumulation moves laterally away from the plane x=0 and towards the plane z=0. The presence of the point of accumulation is entirely due to the presence of lateral diffusion. (author)

  14. Detection of O-propargyl-puromycin with SUMO and ubiquitin by click chemistry at PML-nuclear bodies during abortive proteasome activities

    Energy Technology Data Exchange (ETDEWEB)

    Uozumi, Naoki; Matsumoto, Hotaru [Course for Biological Sciences, Faculty of Science, Kumamoto University, Kumamoto (Japan); Saitoh, Hisato, E-mail: hisa@kumamoto-u.ac.jp [Course for Biological Sciences, Faculty of Science, Kumamoto University, Kumamoto (Japan); Department of Biological Sciences, Graduate School of Science and Technology, Kumamoto University, Kumamoto (Japan)

    2016-05-27

    The amino-nucleoside antibiotic, puromycin, acts by covalently linking to elongating polypeptide chains on ribosomes to generate prematurely terminated immature polypeptides. The trafficking of puromycin-conjugated (puromycylated) immature polypeptides within cell has, however, remained elusive. In this study, using O-propargyl-puromycin (OP-Puro), the distribution of puromycylated polypeptides was assessed in HeLa cells by click chemistry. Under standard culture conditions, OP-Puro signals were detected in the cytoplasm and nucleus with the highest concentrations in the nucleolus. Intriguingly, when proteasome activities were aborted using MG132, OP-Puro signals began to accumulate at promyelocytic leukemia nuclear bodies (PML-NBs) in addition to the nucleolus. We also found promiscuous association of OP-Puro signals with SUMO-2/3 and ubiquitin at PML-NBs, but not at the nucleolus, during abortive proteasome activities. This study reveals a previously unknown distribution of OP-Puro that argues for a nuclear function in regulating immature protein homeostasis. -- Highlights: •Click chemistry detects O-propargyl-puromycin (OP-Puro) signals in the nucleus. •OP-Puro accumulates at PML-NBs during abortive proteasome activities. •SUMO and ubiquitin are promiscuously associated with OP-Puro at PML-NBs. •The nucleus may function in immature protein homeostasis.

  15. Detection of O-propargyl-puromycin with SUMO and ubiquitin by click chemistry at PML-nuclear bodies during abortive proteasome activities

    International Nuclear Information System (INIS)

    Uozumi, Naoki; Matsumoto, Hotaru; Saitoh, Hisato

    2016-01-01

    The amino-nucleoside antibiotic, puromycin, acts by covalently linking to elongating polypeptide chains on ribosomes to generate prematurely terminated immature polypeptides. The trafficking of puromycin-conjugated (puromycylated) immature polypeptides within cell has, however, remained elusive. In this study, using O-propargyl-puromycin (OP-Puro), the distribution of puromycylated polypeptides was assessed in HeLa cells by click chemistry. Under standard culture conditions, OP-Puro signals were detected in the cytoplasm and nucleus with the highest concentrations in the nucleolus. Intriguingly, when proteasome activities were aborted using MG132, OP-Puro signals began to accumulate at promyelocytic leukemia nuclear bodies (PML-NBs) in addition to the nucleolus. We also found promiscuous association of OP-Puro signals with SUMO-2/3 and ubiquitin at PML-NBs, but not at the nucleolus, during abortive proteasome activities. This study reveals a previously unknown distribution of OP-Puro that argues for a nuclear function in regulating immature protein homeostasis. -- Highlights: •Click chemistry detects O-propargyl-puromycin (OP-Puro) signals in the nucleus. •OP-Puro accumulates at PML-NBs during abortive proteasome activities. •SUMO and ubiquitin are promiscuously associated with OP-Puro at PML-NBs. •The nucleus may function in immature protein homeostasis.

  16. Neutron and gamma-ray sources in LWR high-level nuclear waste

    International Nuclear Information System (INIS)

    Dupree, S.A.

    1977-06-01

    Predictions of the composition of high-level waste from U-fueled LWRs have been used to calculate the neutron and gamma-ray sources in such waste at cooling times of 3 and 10 years. The results are intended for interim application to studies of waste shipping and storage pending the availability of more exact knowledge of fuel recycling and of waste concentration and solidification

  17. Base voltammetric characterization of phenylazide modified deoxycytidine - the potential DNA redox label enabling its post-synthetic modifications by "click-reactions"

    Czech Academy of Sciences Publication Activity Database

    Daňhel, Aleš; Trošanová, Zuzana; Balintová, Jana; Havran, Luděk; Hocek, Michal; Fojta, Miroslav

    2013-01-01

    Roč. 9, č. 1 (2013), s. 140-141 ISSN 1336-7242. [Zjazd chemikov /65./. 09.09.2013-13.09.2013, Tatranské Matliare] R&D Projects: GA ČR GBP206/12/G151; GA AV ČR(CZ) IAA400040901 Grant - others:MŠMT(CZ) CZ.1.07/2.3.00/30.0019 Institutional support: RVO:61388963 ; RVO:68081707 Keywords : DNA redox label * click-reaction Subject RIV: CC - Organic Chemistry

  18. Facile preparation of organic-silica hybrid monolith for capillary hydrophilic liquid chromatography based on "thiol-ene" click chemistry.

    Science.gov (United States)

    Chen, Ming-Luan; Zhang, Jun; Zhang, Zheng; Yuan, Bi-Feng; Yu, Qiong-Wei; Feng, Yu-Qi

    2013-04-05

    In this work, a one-step approach to facile preparation of organic-inorganic hybrid monoliths was successfully developed. After vinyl-end organic monomers and azobisisobutyronitrile (AIBN) were mixed with hydrolyzed tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS), the homogeneous mixture was introduced into a fused-silica capillary for simultaneous polycondensation and "thiol-ene" click reaction to form the organic-silica hybrid monoliths. By employing this strategy, two types of organic-silica hybrid monoliths with positively charged quaternary ammonium and amide groups were prepared, respectively. The functional groups were successfully introduced onto the monoliths during the sol-gel process with "thiol-ene" click reaction, which was demonstrated by ζ-potential assessment, energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared (FT-IR) spectroscopy. The porous structure of the prepared monolithic columns was examined by scanning electron microscopy (SEM), nitrogen adsorption-desorption measurement, and mercury intrusion porosimetry. These results indicate the prepared organic-silica hybrid monoliths possess homogeneous column bed, large specific surface area, good mechanical stability, and excellent permeability. The prepared monolithic columns were then applied for anion-exchange/hydrophilic interaction liquid chromatography. Different types of analytes, including benzoic acids, inorganic ions, nucleosides, and nucleotides, were well separated with high column efficiency around 80,000-130,000 plates/m. Taken together, we present a facile and universal strategy to prepare organic-silica hybrid monoliths with a variety of organic monomers using one-step approach. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. A single-phase multi-level D-STATCOM inverter using modular multi-level converter (MMC) topology for renewable energy sources

    Science.gov (United States)

    Sotoodeh, Pedram

    This dissertation presents the design of a novel multi-level inverter with FACTS capability for small to mid-size (10-20kW) permanent-magnet wind installations using modular multi-level converter (MMC) topology. The aim of the work is to design a new type of inverter with D-STATCOM option to provide utilities with more control on active and reactive power transfer of distribution lines. The inverter is placed between the renewable energy source, specifically a wind turbine, and the distribution grid in order to fix the power factor of the grid at a target value, regardless of wind speed, by regulating active and reactive power required by the grid. The inverter is capable of controlling active and reactive power by controlling the phase angle and modulation index, respectively. The unique contribution of the proposed work is to combine the two concepts of inverter and D-STATCOM using a novel voltage source converter (VSC) multi-level topology in a single unit without additional cost. Simulations of the proposed inverter, with 5 and 11 levels, have been conducted in MATLAB/Simulink for two systems including 20 kW/kVAR and 250 W/VAR. To validate the simulation results, a scaled version (250 kW/kVAR) of the proposed inverter with 5 and 11 levels has been built and tested in the laboratory. Experimental results show that the reduced-scale 5- and 11-level inverter is able to fix PF of the grid as well as being compatible with IEEE standards. Furthermore, total cost of the prototype models, which is one of the major objectives of this research, is comparable with market prices.

  20. Sources of innovation, their combinations and strengths – benefits at the NPD project level

    DEFF Research Database (Denmark)

    Tranekjer, Tina Lundø; Søndergaard, Helle Alsted

    2013-01-01

    External sourcing is increasingly seen as important for obtaining new and valuable knowledge and resources for new product development. However, when it comes to the specifics of choosing between sources and types of relationships, little is known on the NPD project level. This paper strengthens...... not only consider the potential benefits of collaboration with external sources but also the downsides, including higher cost and lengthier projects. Firms should look for opportunities in the combination of sources if they are to gain advantages of collaboration, as our analyses show that a mix of market...... and science sources is related to decreased costs. Additionally, if firms are looking for increased market performance, they should aim at collaborating with suppliers that have a similar knowledge base, whereas if the aim is lower project costs, collaboration with a customer with a similar knowledge base...

  1. Levels, Composition and Sources of PM in the Mexico City Metropolitan Area During the MILAGRO Campaign

    Science.gov (United States)

    Querol, X.; Pey, J.; Minguillon, M. C.; Perez, N.; Alastuey, A.; Moreno, T.; Bernabe, R.; Blanco, S.; Cardenas, B.

    2007-05-01

    Particle air pollution in urban agglomerations comes mostly from anthropogenic sources, mainly traffic, industrial processes, energy production, domestic and residential emissions, construction, but also a minor contribution from natural sources may be expected (bioaerosols, soil dust, marine aerosol). Once emitted into the atmosphere, this complex mixture of pollutants may be transformed as a function of the ambient conditions and the interaction among the different PM components, and also between PM components and gaseous pollutants. This system is especially complex in mega-cities due to the large emission volumes of PM components and gaseous precursors, the high variability and broad distribution of emission sources, and the possible long range transport of the polluted air masses. Speciation studies help to identify major sources of PM components with the end objective of applying plans and programs for PM pollution abatement. In this framework, concentration levels and compositions of particulate matter (PM2.5, PM10 and TSP) have been measured simultaneously at two sites in the Mexico City Metropolitan Area (T0 and CENICA) and at one site 50 km away from Mexico City (T1) during the MILAGRO campaign (1st to 31st March 2006). Spatial and time (day and night) variations have been analysed. Coarse fraction levels were higher at T1 than at CENICA and T0, contrary to what was expected. This was due to the important soil re-suspension at T1, contributing significantly to the crustal load. Moreover, crustal levels were higher during daytime than during nights at all sites, while some secondary compounds (sulphate and ammonium) presented an opposite trend. Regarding trace elements, levels of Pb, Zn and Cd were higher at T0 than at CENICA and T1, probably due to traffic contribution. Arsenic levels did not show a clear pattern, being alternatively higher at CENICA and T0. Two intense episodes of Hg particulate have been recorded, more noticeable at T1 than at the urban

  2. Trading of dynamic interaural time and level difference cues and its effect on the auditory motion-onset response measured with electroencephalography.

    Science.gov (United States)

    Altmann, Christian F; Ueda, Ryuhei; Bucher, Benoit; Furukawa, Shigeto; Ono, Kentaro; Kashino, Makio; Mima, Tatsuya; Fukuyama, Hidenao

    2017-10-01

    Interaural time (ITD) and level differences (ILD) constitute the two main cues for sound localization in the horizontal plane. Despite extensive research in animal models and humans, the mechanism of how these two cues are integrated into a unified percept is still far from clear. In this study, our aim was to test with human electroencephalography (EEG) whether integration of dynamic ITD and ILD cues is reflected in the so-called motion-onset response (MOR), an evoked potential elicited by moving sound sources. To this end, ITD and ILD trajectories were determined individually by cue trading psychophysics. We then measured EEG while subjects were presented with either static click-trains or click-trains that contained a dynamic portion at the end. The dynamic part was created by combining ITD with ILD either congruently to elicit the percept of a right/leftward moving sound, or incongruently to elicit the percept of a static sound. In two experiments that differed in the method to derive individual dynamic cue trading stimuli, we observed an MOR with at least a change-N1 (cN1) component for both the congruent and incongruent conditions at about 160-190 ms after motion-onset. A significant change-P2 (cP2) component for both the congruent and incongruent ITD/ILD combination was found only in the second experiment peaking at about 250 ms after motion onset. In sum, this study shows that a sound which - by a combination of counter-balanced ITD and ILD cues - induces a static percept can still elicit a motion-onset response, indicative of independent ITD and ILD processing at the level of the MOR - a component that has been proposed to be, at least partly, generated in non-primary auditory cortex. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Source term evaluation model for high-level radioactive waste repository with decay chain build-up.

    Science.gov (United States)

    Chopra, Manish; Sunny, Faby; Oza, R B

    2016-09-18

    A source term model based on two-component leach flux concept is developed for a high-level radioactive waste repository. The long-lived radionuclides associated with high-level waste may give rise to the build-up of activity because of radioactive decay chains. The ingrowths of progeny are incorporated in the model using Bateman decay chain build-up equations. The model is applied to different radionuclides present in the high-level radioactive waste, which form a part of decay chains (4n to 4n + 3 series), and the activity of the parent and daughter radionuclides leaching out of the waste matrix is estimated. Two cases are considered: one when only parent is present initially in the waste and another where daughters are also initially present in the waste matrix. The incorporation of in situ production of daughter radionuclides in the source is important to carry out realistic estimates. It is shown that the inclusion of decay chain build-up is essential to avoid underestimation of the radiological impact assessment of the repository. The model can be a useful tool for evaluating the source term of the radionuclide transport models used for the radiological impact assessment of high-level radioactive waste repositories.

  4. A recommended procedure for establishing the source level relationships between heroin case samples of unknown origins

    Directory of Open Access Journals (Sweden)

    Kar-Weng Chan

    2014-06-01

    Full Text Available A recent concern of how to reliably establish the source level relationships of heroin case samples is addressed in this paper. Twenty-two trafficking heroin case samples of unknown origins seized from two major regions (Kuala Lumpur and Penang in Malaysia were studied. A procedure containing six major steps was followed to analyze and classify these samples. Subsequently, with the aid of statistical control samples, reliability of the clustering result was assessed. The final outcome reveals that the samples seized from the two regions in 2013 had highly likely originated from two different sources. Hence, the six-step procedure is sufficient for any chemist who attempts to assess the relative source level relationships of heroin samples.

  5. A new hydrostatic leveling system developed for the Advanced Photon Source

    International Nuclear Information System (INIS)

    Kivioja, L. A.

    1998-01-01

    As a result of the calibration tests performed with the first prototype units using the new measurement principle, we believe that the described leveling method is stable and accurate to the micron level with a sufficiently large range for the expected elevation changes of the support girders used in the Advanced Photon Source (APS) storage ring. Although long-term studies with this system have not been conducted, we believe that after installation this system requires little or no servicing for long periods of time. The methods described in this paper cover only the elevation changes of individual vessels. However, changes in the tilt of a girder must also be known. Therefore, a combination of tiltmeters in conjunction with this hydrostatic level system (HLS) would be most suitable for measuring the tilt and elevation changes of the APS girders

  6. Effects of source and level of nitrogen on the utilization of sorghum ...

    African Journals Online (AJOL)

    Acid detergent fibre (ADF) and neutral detergent fibre (NDF) intakes, CP, ADF and NDF digestibilities, digestible ADF and NDF intakes, stover intake and in vitro VFA concentration were not significantly (P>0.05) affected by either main effects of CP source and level or their interaction. The rams on the 16% CSC and 12% ...

  7. Thiol-Ene Photo-Click Collagen-PEG Hydrogels: Impact of Water-Soluble Photoinitiators on Cell Viability, Gelation Kinetics and Rheological Properties

    Directory of Open Access Journals (Sweden)

    Róisín Holmes

    2017-06-01

    Full Text Available Thiol-ene photo-click hydrogels were prepared via step-growth polymerisation using thiol-functionalised type-I collagen and 8-arm poly(ethylene glycol norbornene-terminated (PEG-NB, as a potential injectable regenerative device. Type-I collagen was thiol-functionalised by a ring opening reaction with 2-iminothiolane (2IT, whereby up to 80 Abs.% functionalisation and 90 RPN% triple helical preservation were recorded via 2,4,6-Trinitrobenzenesulfonic acid (TNBS colorimetric assay and circular dichroism (CD. Type, i.e., either 2-Hydroxy-1-[4-(2-hydroxyethoxy phenyl]-2-methyl-1-propanone (I2959 or lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP, and concentration of photoinitiator were varied to ensure minimal photoinitiator-induced cytotoxicity and to enable thiol-ene network formation of collagen-PEG mixtures. The viability of G292 cells following 24 h culture in photoinitiator-supplemented media was largely affected by the photoinitiator concentration, with I2959-supplemented media observed to induce higher toxic response (0.1 → 0.5% (w/v I2959, cell survival: 62 → 2 Abs.% compared to LAP-supplemented media (cell survival: 86 → 8 Abs.%. In line with the in vitro study, selected photoinitiator concentrations were used to prepare thiol-ene photo-click hydrogels. Gelation kinetics proved to be largely affected by the specific photoinitiator, with LAP-containing thiol-ene mixtures leading to significantly reduced complete gelation time (τ: 187 s with respect to I2959-containing mixtures (τ: 1683 s. Other than the specific photoinitiator, the photoinitiator concentration was key to adjusting the hydrogel storage modulus (G’, whereby 15-fold G’ increase (232 → 3360 Pa was observed in samples prepared with 0.5% (w/v compared to 0.1% (w/v LAP. Further thiol-ene formulations with 0.5% (w/v LAP and varied content of PEG-NB were tested to prepare photo-click hydrogels with porous architecture, as well as tunable storage modulus (G

  8. Direct Power Control for Three-Phase Two-Level Voltage-Source Rectifiers Based on Extended-State Observation

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Yan, Zhuo

    2016-01-01

    This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent characte......This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent...

  9. Low levels of persistent organic pollutants (POPs) in New Zealand eels reflect isolation from atmospheric sources

    International Nuclear Information System (INIS)

    Holmqvist, Niklas; Stenroth, Patrik; Berglund, Olof; Nystroem, Per; Olsson, Karin; Jellyman, Don; McIntosh, Angus R.; Larsson, Per

    2006-01-01

    Polychlorinated biphenyls (PCBs) and organic pesticides (i.e., DDTs) were measured in long finned eels (Anguilla dieffenbachii) in 17 streams on the west coast of South Island, New Zealand. Very low levels of PCBs and low levels of ppDDE were found. The concentrations of PCBs and ppDDE were not correlated within sites indicating that different processes determined the levels of the two pollutants in New Zealand eels. The PCBs probably originate from atmospheric transport, ppDDE levels are determined by land use and are higher in agriculture areas. The low contamination level of these aquatic systems seems to be a function of a low input from both long and short-range transport as well as few local point sources. No correlation could be found between lipid content and persistent organic pollutants (POPs) concentration (as shown in previous studies) in the eels which could be explained by low and irregular intake of the pollutants. - Low levels of PCBs found in New Zealand eels reflect isolation from atmospheric sources while DDTs levels are determined by land use

  10. Comparative case study on website traffic generated by search engine optimisation and a pay-per-click campaign, versus marketing expenditure

    OpenAIRE

    Wouter T. Kritzinger; Melius Weideman

    2015-01-01

    Background: No empirical work was found on how marketing expenses compare when used solely for either the one or the other of the two main types of search engine marketing. Objectives: This research set out to determine how the results of the implementation of a pay-per-click campaign compared to those of a search engine optimisation campaign, given the same website and environment. At the same time, the expenses incurred on both these marketing methods were recorded and compared. M...

  11. Prey capture by harbour porpoises

    DEFF Research Database (Denmark)

    Verfuss, Ursula; Miller, Lee; Pilz, Peter

    their ultrasonic clicks as biosonar for orientation and detection of prey (mostly smaller pelagic and bottom dwelling fish), and for communication.  For studying wild animals, hydrophone arrays [Villadsgaard et al. J.Exp.Biol. 210 (2007)] and acoustic (time/depth) tags [Akamatsu et al. Deep Sea Research II 54...... (2007)] have been used.  For studying captive animals, arrays and video techniques [Verfuß et al. J.Exp.Biol. 208 (2005)] as well as miniature acoustic-behavioral tags [Deruiter et al. JASA 123 (2008)] have been used.  While searching for prey, harbor porpoises use clicks at long intervals (>50 ms......) that progressively decrease when closing on a landmark.  The source levels of captive animals reduce by about half for each halving of the distance to the target.  After detecting the prey, the click interval first stabilizes at about 50 ms and then becomes progressively shorter while approaching the prey...

  12. Facile synthesis of linear-dendritic cholesteryl-poly(epsilon-caprolactone)-b-(L-lysine)(G2) by thiol-ene and azide-alkyne "click" reactions

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Binder, W.H.; Tanner, S.

    2010-01-01

    The construction of a linear-dendritic block copolymer consisting of terminal cholesteryl moiety, poly(epsilon-caprolactone), and a second generation L-lysine dendron has been accomplished by the combination of copper(I) catalyzed azide-alkyne and UV-triggered thiol-ene "click" reactions. Ring-op...... and thiocholesterol. Near to quantitative functionalization of the intermediate and final products has been attained as confirmed by NMR spectroscopy and MALDI-TOF spectrometry....

  13. Recurrent Embolic Strokes of Undetermined Source in a Patient with Extreme Lipoprotein(a Levels

    Directory of Open Access Journals (Sweden)

    Zachary Bulwa

    2016-08-01

    Full Text Available Lipoprotein(a is a plasma lipoprotein and known cardiovascular risk factor most recently implicated in the development of high-risk carotid atherosclerotic plaques without significant carotid stenosis. We present a case of a young African-American female with recurrent embolic strokes of undetermined source. After our thorough investigation we identified the link between a small, irregular plaque in the right internal carotid artery and an extremely elevated plasma level of lipoprotein(a as the source of her embolic strokes.

  14. Source terms for analysis of accidents at a high level waste repository

    International Nuclear Information System (INIS)

    Mubayi, V.; Davis, R.E.; Youngblood, R.

    1989-01-01

    This paper describes an approach to identifying source terms from possible accidents during the preclosure phase of a high-level nuclear waste repository. A review of the literature on repository safety analyses indicated that source term estimation is in a preliminary stage, largely based on judgement-based scoping analyses. The approach developed here was to partition the accident space into domains defined by certain threshold values of temperature and impact energy density which may arise in potential accidents and specify release fractions of various radionuclides, present in the waste form, in each domain. Along with a more quantitative understanding of accident phenomenology, this approach should help in achieving a clearer perspective on scenarios important to preclosure safety assessments of geologic repositories. 18 refs., 3 tabs

  15. Advertisement Click-Through Rate Prediction Based on the Weighted-ELM and Adaboost Algorithm

    Directory of Open Access Journals (Sweden)

    Sen Zhang

    2017-01-01

    Full Text Available Accurate click-through rate (CTR prediction can not only improve the advertisement company’s reputation and revenue, but also help the advertisers to optimize the advertising performance. There are two main unsolved problems of the CTR prediction: low prediction accuracy due to the imbalanced distribution of the advertising data and the lack of the real-time advertisement bidding implementation. In this paper, we will develop a novel online CTR prediction approach by incorporating the real-time bidding (RTB advertising by the following strategies: user profile system is constructed from the historical data of the RTB advertising to describe the user features, the historical CTR features, the ID features, and the other numerical features. A novel CTR prediction approach is presented to address the imbalanced learning sample distribution by integrating the Weighted-ELM (WELM and the Adaboost algorithm. Compared to the commonly used algorithms, the proposed approach can improve the CTR significantly.

  16. Clicked Cinnamic/Caffeic Esters and Amides as Radical Scavengers and 5-Lipoxygenase Inhibitors

    Directory of Open Access Journals (Sweden)

    Jérémie A. Doiron

    2014-01-01

    Full Text Available 5-Lipoxygenase (5-LO is the key enzyme responsible for the conversion of arachidonic acid to leukotrienes, a class of lipid mediators implicated in inflammatory disorders. In this paper, we describe the design, synthesis, and preliminary activity studies of novel clicked caffeic esters and amides as radical scavengers and 5-LO inhibitors. From known 5-LO inhibitor 3 as a lead, cinnamic esters 8a–h and amides 9a–h as well as caffeic esters 15a–h and amides 16a–h were synthesized by Cu(I-catalyzed [1,3]-dipolar cycloaddition with the appropriate azide precursors and terminal alkynes. All caffeic analogs are proved to be good radical scavengers (IC50: 10–20 μM. Esters 15g and 15f possessed excellent 5-LO inhibition activity in HEK293 cells and were equipotent with the known 5-LO inhibitor CAPE and more potent than Zileuton. Several synthesized esters possess activities rivaling Zileuton in stimulated human polymorphonuclear leukocytes.

  17. Improved Thermal-Vacuum Compatible Flat Plate Radiometric Source For System-Level Testing Of Optical Sensors

    Science.gov (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.

    2016-01-01

    In this work, we describe an improved thermal-vacuum compatible flat plate radiometric source which has been developed and utilized for the characterization and calibration of remote optical sensors. This source is unique in that it can be used in situ, in both ambient and thermal-vacuum environments, allowing it to follow the sensor throughout its testing cycle. The performance of the original flat plate radiometric source was presented at the 2009 SPIE1. Following the original efforts, design upgrades were incorporated into the source to improve both radiometric throughput and uniformity. The pre-thermal-vacuum (pre-TVAC) testing results of a spacecraft-level optical sensor with the improved flat plate illumination source, both in ambient and vacuum environments, are presented. We also briefly discuss potential FPI configuration changes in order to improve its radiometric performance.

  18. Five-Level Current-Source Inverters With Buck–Boost and Inductive-Current Balancing Capabilities

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2010-01-01

    This paper presents new five-level current-source inverters (CSIs) with voltage/current buck–boost capability, unlike existing five-level CSIs where only voltage–boost operation is supported. The proposed inverters attain self-inductive-currentbalancing per switching cycle at their dc front ends...... without having to include additional balancing hardware or complex control manipulation. The inverters can conveniently be controlled by using the well-established phase-shifted carrier modulation scheme with only two additional linear references and a mapping logic table needed. Existing modulators can...

  19. The effect of plant identity and the level of plant decay on molecular gut content analysis in a herbivorous soil insect

    OpenAIRE

    Wallinger, Corinna; Staudacher, Karin; Schallhart, Nikolaus; Peter, Eva; Dresch, Philipp; Juen, Anita; Traugott, Michael

    2012-01-01

    Plant roots represent an important food source for soil-dwelling animals, but tracking herbivore food choices below-ground is difficult. Here, we present an optimized PCR assay for the detection of plant DNA in the guts of invertebrates, using general plant primers targeting the trnT-F chloroplast DNA region. Based on this assay, we assessed the influence of plant identity on the detectability of ingested plant DNA in Agriotes click beetle larvae. Six different plant species were fed to the i...

  20. Interobserver-variability of lung nodule volumetry considering different segmentation algorithms and observer training levels

    International Nuclear Information System (INIS)

    Bolte, H.; Jahnke, T.; Schaefer, F.K.W.; Wenke, R.; Hoffmann, B.; Freitag-Wolf, S.; Dicken, V.; Kuhnigk, J.M.; Lohmann, J.; Voss, S.; Knoess, N.

    2007-01-01

    Objective: The aim of this study was to investigate the interobserver variability of CT based diameter and volumetric measurements of artificial pulmonary nodules. A special interest was the consideration of different measurement methods, observer experience and training levels. Materials and methods: For this purpose 46 artificial small solid nodules were examined in a dedicated ex-vivo chest phantom with multislice-spiral CT (20 mAs, 120 kV, collimation 16 mm x 0.75 mm, table feed 15 mm, reconstructed slice thickness 1 mm, reconstruction increment 0.7 mm, intermediate reconstruction kernel). Two observer groups of different radiologic experience (0 and more than 5 years of training, 3 observers each) analysed all lesions with digital callipers and 2 volumetry software packages (click-point depending and robust volumetry) in a semi-automatic and manually corrected mode. For data analysis the variation coefficient (VC) was calculated in per cent for each group and a Wilcoxon test was used for analytic statistics. Results: Click-point robust volumetry showed with a VC of <0.01% in both groups the smallest interobserver variability. Between experienced and un-experienced observers interobserver variability was significantly different for diameter measurements (p = 0.023) but not for semi-automatic and manual corrected volumetry. A significant training effect was revealed for diameter measurements (p = 0.003) and semi-automatic measurements of click-point depending volumetry (p = 0.007) in the un-experienced observer group. Conclusions: Compared to diameter measurements volumetry achieves a significantly smaller interobserver variance and advanced volumetry algorithms are independent of observer experience

  1. Ultramild protein-mediated click chemistry creates efficient oligonucleotide probes for targeting and detecting nucleic acids

    DEFF Research Database (Denmark)

    Nåbo, Lina J.; Madsen, Charlotte S.; Jensen, Knud J.

    2015-01-01

    Functionalized synthetic oligonucleotides are finding growing applications in research, clinical studies, and therapy. However, it is not easy to prepare them in a biocompatible and highly efficient manner. We report a new strategy to synthesize oligonucleotides with promising nucleic acid...... targeting and detection properties. We focus in particular on the pH sensitivity of these new probes and their high target specificity. For the first time, human copper(I)-binding chaperon Cox17 was applied to effectively catalyze click labeling of oligonucleotides. This was performed under ultramild...... conditions with fluorophore, peptide, and carbohydrate azide derivatives. In thermal denaturation studies, the modified probes showed specific binding to complementary DNA and RNA targets. Finally, we demonstrated the pH sensitivity of the new rhodamine-based fluorescent probes in vitro and rationalize our...

  2. Low-level radioactive waste source terms for the 1992 integrated data base

    International Nuclear Information System (INIS)

    Loghry, S.L.; Kibbey, A.H.; Godbee, H.W.; Icenhour, A.S.; DePaoli, S.M.

    1995-01-01

    This technical manual presents updated generic source terms (i.e., unitized amounts and radionuclide compositions) which have been developed for use in the Integrated Data Base (IDB) Program of the U.S. Department of Energy (DOE). These source terms were used in the IDB annual report, Integrated Data Base for 1992: Spent Fuel and Radioactive Waste Inventories, Projections, and Characteristics, DOE/RW-0006, Rev. 8, October 1992. They are useful as a basis for projecting future amounts (volume and radioactivity) of low-level radioactive waste (LLW) shipped for disposal at commercial burial grounds or sent for storage at DOE solid-waste sites. Commercial fuel cycle LLW categories include boiling-water reactor, pressurized-water reactor, fuel fabrication, and uranium hexafluoride (UF 6 ) conversion. Commercial nonfuel cycle LLW includes institutional/industrial (I/I) waste. The LLW from DOE operations is category as uranium/thorium fission product, induced activity, tritium, alpha, and open-quotes otherclose quotes. Fuel cycle commercial LLW source terms are normalized on the basis of net electrical output [MW(e)-year], except for UF 6 conversion, which is normalized on the basis of heavy metal requirement [metric tons of initial heavy metal ]. The nonfuel cycle commercial LLW source term is normalized on the basis of volume (cubic meters) and radioactivity (curies) for each subclass within the I/I category. The DOE LLW is normalized in a manner similar to that for commercial I/I waste. The revised source terms are based on the best available historical data through 1992

  3. Extremely efficient catalysis of carbon-carbon bond formation using "click" dendrimer-stabilized palladium nanoparticles.

    Science.gov (United States)

    Astruc, Didier; Ornelas, Cátia; Diallo, Abdou K; Ruiz, Jaime

    2010-07-20

    This article is an account of the work carried out in the authors' laboratory illustrating the usefulness of dendrimer design for nanoparticle palladium catalysis. The "click" synthesis of dendrimers constructed generation by generation by 1-->3 C connectivity, introduces 1,2,3-triazolyl ligands insides the dendrimers at each generation. Complexation of the ligands by Pd(II) followed by reduction to Pd(0) forms dendrimer-stabilized Pd nanoparticles (PdNPs) that are extremely reactive in the catalysis of olefin hydrogenation and C-C bond coupling reactions. The stabilization can be outer-dendritic for the small zeroth-generation dendrimer or intra-dendritic for the larger first- and second-generation dendrimers. The example of the Miyaura-Suzuki reaction that can be catalyzed by down to 1 ppm of PdNPs with a "homeopathic" mechanism (the less, the better) is illustrated here, including catalysis in aqueous solvents.

  4. Direct Profiling the Post-Translational Modification Codes of a Single Protein Immobilized on a Surface Using Cu-free Click Chemistry.

    Science.gov (United States)

    Kim, Kyung Lock; Park, Kyeng Min; Murray, James; Kim, Kimoon; Ryu, Sung Ho

    2018-05-23

    Combinatorial post-translational modifications (PTMs), which can serve as dynamic "molecular barcodes", have been proposed to regulate distinct protein functions. However, studies of combinatorial PTMs on single protein molecules have been hindered by a lack of suitable analytical methods. Here, we describe erasable single-molecule blotting (eSiMBlot) for combinatorial PTM profiling. This assay is performed in a highly multiplexed manner and leverages the benefits of covalent protein immobilization, cyclic probing with different antibodies, and single molecule fluorescence imaging. Especially, facile and efficient covalent immobilization on a surface using Cu-free click chemistry permits multiple rounds (>10) of antibody erasing/reprobing without loss of antigenicity. Moreover, cumulative detection of coregistered multiple data sets for immobilized single-epitope molecules, such as HA peptide, can be used to increase the antibody detection rate. Finally, eSiMBlot enables direct visualization and quantitative profiling of combinatorial PTM codes at the single-molecule level, as we demonstrate by revealing the novel phospho-codes of ligand-induced epidermal growth factor receptor. Thus, eSiMBlot provides an unprecedentedly simple, rapid, and versatile platform for analyzing the vast number of combinatorial PTMs in biological pathways.

  5. Reduction-responsive interlayer-crosslinked micelles prepared from star-shaped copolymer via click chemistry for drug controlled release

    Science.gov (United States)

    Dai, Yu; Wang, Hongquan; Zhang, Xiaojin

    2017-12-01

    To improve the stability of polymeric micelles, here we describe interlayer-crosslinked micelles prepared from star-shaped copolymer via click chemistry. The formation of interlayer-crosslinked micelles was investigated and confirmed by proton nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and fluorescence spectroscopy. The morphology of un-crosslinked micelles and crosslinked micelles observed by transmission electron microscope is both uniform nano-sized spheres (approximately 20 nm). The crosslinking enhances the stability of polymeric micelles and improves the drug loading capacity of polymeric micelles. The interlayer-crosslinked micelles prepared from star-shaped copolymer and a crosslinker containing a disulfide bond are reduction-responsive and can release the drug quickly in the presence of the reducing agents such as glutathione (GSH).

  6. Household Air Pollution: Sources and Exposure Levels to Fine Particulate Matter in Nairobi Slums

    Directory of Open Access Journals (Sweden)

    Kanyiva Muindi

    2016-07-01

    Full Text Available With 2.8 billion biomass users globally, household air pollution remains a public health threat in many low- and middle-income countries. However, little evidence on pollution levels and health effects exists in low-income settings, especially slums. This study assesses the levels and sources of household air pollution in the urban slums of Nairobi. This cross-sectional study was embedded in a prospective cohort of pregnant women living in two slum areas—Korogocho and Viwandani—in Nairobi. Data on fuel and stove types and ventilation use come from 1058 households, while air quality data based on the particulate matters (PM2.5 level were collected in a sub-sample of 72 households using the DustTrak™ II Model 8532 monitor. We measured PM2.5 levels mainly during daytime and using sources of indoor air pollutions. The majority of the households used kerosene (69.7% as a cooking fuel. In households where air quality was monitored, the mean PM2.5 levels were high and varied widely, especially during the evenings (124.6 µg/m3 SD: 372.7 in Korogocho and 82.2 µg/m3 SD: 249.9 in Viwandani, and in households using charcoal (126.5 µg/m3 SD: 434.7 in Korogocho and 75.7 µg/m3 SD: 323.0 in Viwandani. Overall, the mean PM2.5 levels measured within homes at both sites (Korogocho = 108.9 µg/m3 SD: 371.2; Viwandani = 59.3 µg/m3 SD: 234.1 were high. Residents of the two slums are exposed to high levels of PM2.5 in their homes. We recommend interventions, especially those focusing on clean cookstoves and lighting fuels to mitigate indoor levels of fine particles.

  7. Synthesis and Relaxivity Studies of a DOTA-Based Nanomolecular Chelator Assembly Supported by an Icosahedral Closo-B122− -Core for MRI: A Click Chemistry Approach

    Directory of Open Access Journals (Sweden)

    Satish S. Jalisatgi

    2013-07-01

    Full Text Available An icosahedral closo-B122− scaffold based nano-sized assembly capable of carrying a high payload of Gd3+-chelates in a sterically crowded configuration is developed by employing the azide-alkyne click reaction. The twelve copies of DO3A-t-Bu-ester ligands were covalently attached to an icosahedral closo-B122− core via suitable linkers through click reaction. This nanomolecular structure supporting a high payload of Gd3+-chelate is a new member of the closomer MRI contrast agents that we are currently developing in our laboratory. The per Gd ion relaxivity (r1 of the newly synthesized MRI contrast agent was obtained in PBS, 2% tween/PBS and bovine calf serum using a 7 Tesla micro MRI instrument and was found to be slightly higher (r1 = 4.7 in PBS at 25 °C compared to the clinically used MRI contrast agents Omniscan (r1 = 4.2 in PBS at 25 °C and ProHance (r1 = 3.1 in PBS at 25 °C.

  8. One-Pot Click Access to a Cyclodextrin Dimer-Based Novel Aggregation Induced Emission Sensor and Monomer-Based Chiral Stationary Phase

    Directory of Open Access Journals (Sweden)

    Xiaoli Li

    2016-11-01

    Full Text Available A ‘two birds, one stone’ strategy was developed via a one-pot click reaction to simultaneously prepare a novel cyclodextrin (CD dimer based aggregation induced emission (AIE sensor (AIE-DCD and a monomer based chiral stationary phase (CSP-MCD for chiral high performance liquid chromatography (CHPLC. AIE-DCD was found to afford satisfactory AIE response for specific detection of Zn2+ with a detection limit of 50 nM. CSP-MCD exhibits excellent enantioseparation ability toward dansyl amino acids, where the resolution of dansyl amino leucine reaches 5.43.

  9. Temporally selective processing of communication signals by auditory midbrain neurons

    DEFF Research Database (Denmark)

    Elliott, Taffeta M; Christensen-Dalsgaard, Jakob; Kelley, Darcy B

    2011-01-01

    click rates ranged from 4 to 50 Hz, the rate at which the clicks begin to overlap. Frequency selectivity and temporal processing were characterized using response-intensity curves, temporal-discharge patterns, and autocorrelations of reduplicated responses to click trains. Characteristic frequencies...... of the rate of clicks in calls. The majority of neurons (85%) were selective for click rates, and this selectivity remained unchanged over sound levels 10 to 20 dB above threshold. Selective neurons give phasic, tonic, or adapting responses to tone bursts and click trains. Some algorithms that could compute...

  10. Three-Level AC-DC-AC Z-Source Converter Using Reduced Passive Component Count

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Gao, Feng; Tan, Pee-Chin

    2009-01-01

    This paper presents a three-level ac-dc-ac Z-source converter with output voltage buck-boost capability. The converter is implemented by connecting a low-cost front-end diode rectifier to a neutral-point-clamped inverter through a single X-shaped LC impedance network. The inverter is controlled...... to switch with a three-level output voltage, where the middle neutral potential is uniquely tapped from the star-point of a wye-connected capacitive filter placed before the front-end diode rectifier for input current filtering. Through careful control, the resulting converter can produce the correct volt...

  11. Labeling proteins on live mammalian cells using click chemistry.

    Science.gov (United States)

    Nikić, Ivana; Kang, Jun Hee; Girona, Gemma Estrada; Aramburu, Iker Valle; Lemke, Edward A

    2015-05-01

    We describe a protocol for the rapid labeling of cell-surface proteins in living mammalian cells using click chemistry. The labeling method is based on strain-promoted alkyne-azide cycloaddition (SPAAC) and strain-promoted inverse-electron-demand Diels-Alder cycloaddition (SPIEDAC) reactions, in which noncanonical amino acids (ncAAs) bearing ring-strained alkynes or alkenes react, respectively, with dyes containing azide or tetrazine groups. To introduce ncAAs site specifically into a protein of interest (POI), we use genetic code expansion technology. The protocol can be described as comprising two steps. In the first step, an Amber stop codon is introduced--by site-directed mutagenesis--at the desired site on the gene encoding the POI. This plasmid is then transfected into mammalian cells, along with another plasmid that encodes an aminoacyl-tRNA synthetase/tRNA (RS/tRNA) pair that is orthogonal to the host's translational machinery. In the presence of the ncAA, the orthogonal RS/tRNA pair specifically suppresses the Amber codon by incorporating the ncAA into the polypeptide chain of the POI. In the second step, the expressed POI is labeled with a suitably reactive dye derivative that is directly supplied to the growth medium. We provide a detailed protocol for using commercially available ncAAs and dyes for labeling the insulin receptor, and we discuss the optimal surface-labeling conditions and the limitations of labeling living mammalian cells. The protocol involves an initial cloning step that can take 4-7 d, followed by the described transfections and labeling reaction steps, which can take 3-4 d.

  12. It was nice with the brick so now I'll click: The effects of offline and online experience, perceived benefits, and trust on Dutch consumers' online repeat purchase intention

    NARCIS (Netherlands)

    Beldad, Ardion Daroca; Segers, Mariel; Kurosu, Masaaki

    2013-01-01

    The present study investigated the factors influencing Dutch consumers’ intention to continue purchasing from a brick-and-click clothes shop’s online channel after an initial commercial exchange. Results on the online survey with 513 respondents reveal that their repeat online purchase intention is

  13. Sources

    International Nuclear Information System (INIS)

    Duffy, L.P.

    1991-01-01

    This paper discusses the sources of radiation in the narrow perspective of radioactivity and the even narrow perspective of those sources that concern environmental management and restoration activities at DOE facilities, as well as a few related sources. Sources of irritation, Sources of inflammatory jingoism, and Sources of information. First, the sources of irritation fall into three categories: No reliable scientific ombudsman to speak without bias and prejudice for the public good, Technical jargon with unclear definitions exists within the radioactive nomenclature, and Scientific community keeps a low-profile with regard to public information. The next area of personal concern are the sources of inflammation. This include such things as: Plutonium being described as the most dangerous substance known to man, The amount of plutonium required to make a bomb, Talk of transuranic waste containing plutonium and its health affects, TMI-2 and Chernobyl being described as Siamese twins, Inadequate information on low-level disposal sites and current regulatory requirements under 10 CFR 61, Enhanced engineered waste disposal not being presented to the public accurately. Numerous sources of disinformation regarding low level radiation high-level radiation, Elusive nature of the scientific community, The Federal and State Health Agencies resources to address comparative risk, and Regulatory agencies speaking out without the support of the scientific community

  14. Overview of the Spallation Neutron Source Linac Low-Level RF Control System

    CERN Document Server

    Champion, Mark; Doolittle, Lawrence; Kasemir, Kay-Uwe; Ma, Hengjie; Piller, Maurice; Ratti, Alessandro

    2005-01-01

    The design and production of the Spallation Neutron Source Linac Low-Level RF control system is complete, and installation will be finished in Spring 2005. The warm linac beam commissioning run in Fall 2004 was the most extensive test to date of the LLRF control system, with fourteen (of an eventual 96) systems operating simultaneously. In this paper we present an overview of the LLRF control system, the experience in designing, building and installing the system, and operational results.

  15. Integrating Protein Engineering and Bioorthogonal Click Conjugation for Extracellular Vesicle Modulation and Intracellular Delivery.

    Directory of Open Access Journals (Sweden)

    Ming Wang

    Full Text Available Exosomes are small, cell-secreted vesicles that transfer proteins and genetic information between cells. This intercellular transmission regulates many physiological and pathological processes. Therefore, exosomes have emerged as novel biomarkers for disease diagnosis and as nanocarriers for drug delivery. Here, we report an easy-to-adapt and highly versatile methodology to modulate exosome composition and conjugate exosomes for intracellular delivery. Our strategy combines the metabolic labeling of newly synthesized proteins or glycan/glycoproteins of exosome-secreting cells with active azides and bioorthogonal click conjugation to modify and functionalize the exosomes. The azide-integrated can be conjugated to a variety of small molecules and proteins and can efficiently deliver conjugates into cells. The metabolic engineering of exosomes diversifies the chemistry of exosomes and expands the functions that can be introduced into exosomes, providing novel, powerful tools to study the roles of exosomes in biology and expand the biomedical potential of exosomes.

  16. Modifying surface resistivity and liquid moisture management property of keratin fibers through thiol-ene click reactions.

    Science.gov (United States)

    Yu, Dan; Cai, Jackie Y; Church, Jeffrey S; Wang, Lijing

    2014-01-22

    This paper reports on a new method for improving the antistatic and liquid moisture management properties of keratinous materials. The method involves the generation of thiols by controlled reduction of cystine disulfide bonds in keratin with tris(2-carboxyethyl) phosphine hydrochloride and subsequent grafting of hydrophilic groups onto the reduced keratin by reaction with an acrylate sulfonate or acrylamide sulfonate through thiol-ene click chemistry. The modified substrates were characterized with Raman spectroscopy and scanning electron microscopy and evaluated for their performance changes in liquid moisture management, surface resistivity, and wet burst strength. The results have revealed that the thiol-acrylate reaction is more efficient than the thiol-acrylamide reaction, and the keratinous substrate modified with an acrylate sulfonate salt exhibits significantly improved antistatic and liquid moisture management properties.

  17. A source term and risk calculations using level 2+PSA methodology

    International Nuclear Information System (INIS)

    Park, S. I.; Jea, M. S.; Jeon, K. D.

    2002-01-01

    The scope of Level 2+ PSA includes the assessment of dose risk which is associated with the exposures of the radioactive nuclides escaping from nuclear power plants during severe accidents. The establishment of data base for the exposure dose in Korea nuclear power plants may contribute to preparing the accident management programs and periodic safety reviews. In this study the ORIGEN, MELCOR and MACCS code were employed to produce a integrated framework to assess the radiation source term risk. The framework was applied to a reference plant. Using IPE results, the dose rate for the reference plant was calculated quantitatively

  18. Effect of source and level of potash on yield and quality of potato tubers

    International Nuclear Information System (INIS)

    Khan, M.Z.; Akhtar, M.E.; Mahmood, M.M.

    2010-01-01

    Field experiments were conducted for two consecutive seasons at NARC potato research area Islamabad, Pakistan, to study comparative effect of source, levels and methods of K fertilization on yield and quality of potato produce. Nitrogen and phosphorus were applied at 250 and 125 kg ha/sup -1/, respectively whereas three K/sub 2/O levels, 0, 150 and 225 kg ha/sup -1/ from two sources of potash (SOP and MOP) were tested. Potassium was also applied as foliar spray at 1% K/sub 2/O solution at 30, 45 and 60 days after germination (DAG) and soil was also amended by 150 kg K/sub 2/O ha/sup -1/. A significant increase in tuber yield with K application at 150 kg ha/sup -1/ as K/sub 2/O from both the K sources over NP treatment was recorded. Increase in tuber yield with K/sub 2/O at the rate of 225 kg ha/sup -1/ was statistically nonsignificant compared to 150 kg K/sub 2/O ha/sup -1/. A positive interaction between soil applied P and K with N in plant system was observed. Potassium treatments not only increased K concentration but also affected N and P contents in potato tubers. The quality parameters like dry matter, specific gravity, starch contents, vitamin-C and ash contents were also affected with P and K fertilization. (author)

  19. Radiation sources, radiation environment and risk level at Dubna

    International Nuclear Information System (INIS)

    Komochkov, M.M.

    1991-01-01

    The overall information about ionizing radiation sources, which form radiation environment and risk at Dubna, is introduced. Systematization of the measurement results is performed on the basis of the effective dose and losses of life expectancy. The contribution of different sources to total harm of Dubna inhabitants has been revealed. JINR sources carry in ∼ 4% from the total effective dose of natural and medicine radiation sources; the harm from them is much less than the harm from cigarette smoking. 18 refs.; 2 tabs

  20. Functionalization of single-walled carbon nanotubes with protein by click chemistry as sensing platform for sensitized electrochemical immunoassay

    International Nuclear Information System (INIS)

    Qi Honglan; Ling Chen; Huang Ru; Qiu Xiaoying; Shangguan Li; Gao Qiang; Zhang Chengxiao

    2012-01-01

    Highlights: ► Single-walled carbon nanotubes were functionalized with protein by click chemistry. ► The SWNTs conjugated with protein showed excellent dispersion in water and kept good bioacitvity. ► A competitive electrochemical immunoassay for the determination of anti-IgG was developed with high sensitivity and good stability. - Abstract: The application of the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition to the functionalization of single-walled carbon nanotubes (SWNTs) with the protein and the use of the artificial SWNTs as a sensing platform for sensitive immunoassay were reported. Covalent functionalization of azide decorated SWNTs with alkyne modified protein was firstly accomplished by the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition. FT-IR spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron micrograph were used to characterize the protein-functionalized SWNTs. It was found that the SWNTs conjugated with the proteins showed excellent dispersion in water and kept good bioacitivity when immunoglobulin (IgG) and horseradish peroxidase (HRP) were chosen as model proteins. As a proof-of-concept, IgG-functionalized SWNTs were immobilized onto the surface of a glassy carbon electrode by simple casting method as immunosensing platform and a sensitive competitive electrochemical immunoassay was developed for the determination of anti-immunoglobulin (anti-IgG) using HRP as enzyme label. The fabrication of the immunosensor were characterized by cyclic voltammetry and electrochemical impedance spectroscopy with the redox probe [Fe(CN) 6 ] 3−/4− . The SWNTs as immobilization platform showed better sensitizing effect, a detection limit of 30 pg mL −1 (S/N = 3) was obtained for anti-IgG. The proposed strategy provided a stable immobilization method and sensitized recognition platform for analytes. This work demonstrated that the click coupling of SWNTs with protein was an effective

  1. Site-specific antibody-liposome conjugation through copper-free click chemistry: a molecular biology approach for targeted photodynamic therapy (Conference Presentation)

    Science.gov (United States)

    Obaid, Girgis; Wang, Yucheng; Kuriakose, Jerrin; Broekgaarden, Mans; Alkhateeb, Ahmed; Bulin, Anne-Laure; Hui, James; Tsourkas, Andrew; Hasan, Tayyaba

    2016-03-01

    Nanocarriers, such as liposomes, have the ability to potentiate photodynamic therapy (PDT) treatment regimens by the encapsulation of high payloads of photosensitizers and enhance their passive delivery to tumors through the enhanced permeability and retention effect. By conjugating targeting moieties to the surface of the liposomal nanoconstructs, cellular selectivity is imparted on them and PDT-based therapies can be performed with significantly higher dose tolerances, as off-target toxicity is simultaneously reduced.1 However, the maximal benefits of conventional targeted nanocarriers, including liposomes, are hindered by practical limitations including chemical instability, non-selective conjugation chemistry, poor control over ligand orientation, and loss of ligand functionality following conjugation, amongst others.2 We have developed a robust, physically and chemically stable liposomal nanoplatform containing benzoporphyrin derivative photosensitizer molecules within the phospholipid bilayer and an optimized surface density of strained cyclooctyne moieties for `click' conjugation to azido-functionalized antibodies.3 The clinical chimeric anti-EGFR antibody Cetuximab is site-specifically photocrosslinked to a recombinant bioengineered that recognizes the antibody's Fc region, containing a terminal azide.4 The copper-free click conjugation of the bioengineered Cetuximab derivative to the optimized photosensitizing liposome provides exceptional control over the antibody's optimal orientation for cellular antigen binding. Importantly, the reaction occurs rapidly under physiological conditions, bioorthogonally (selectively in the presence of other biomolecules) and without the need for toxic copper catalysis.3 Such state-of-the-art conjugation strategies push the boundaries of targeted photodynamic therapy beyond the limitations of traditional chemical coupling techniques to produce more robust and effective targeted therapeutics with applications beyond

  2. Atmospheric polychlorinated biphenyls in Indian cities: Levels, emission sources and toxicity equivalents

    International Nuclear Information System (INIS)

    Chakraborty, Paromita; Zhang, Gan; Eckhardt, Sabine; Li, Jun; Breivik, Knut; Lam, Paul K.S.; Tanabe, Shinsuke; Jones, Kevin C.

    2013-01-01

    Atmospheric concentration of Polychlorinated biphenyls (PCBs) were measured on diurnal basis by active air sampling during Dec 2006 to Feb 2007 in seven major cities from the northern (New Delhi and Agra), eastern (Kolkata), western (Mumbai and Goa) and southern (Chennai and Bangalore) parts of India. Average concentration of Σ 25 PCBs in the Indian atmosphere was 4460 (±2200) pg/m −3 with a dominance of congeners with 4–7 chlorine atoms. Model results (HYSPLIT, FLEXPART) indicate that the source areas are likely confined to local or regional proximity. Results from the FLEXPART model show that existing emission inventories cannot explain the high concentrations observed for PCB-28. Electronic waste, ship breaking activities and dumped solid waste are attributed as the possible sources of PCBs in India. Σ 25 PCB concentrations for each city showed significant linear correlation with Toxicity equivalence (TEQ) and Neurotoxic equivalence (NEQ) values. Highlights: •Unlike decreasing trend of PCBs in United States and European countries, high levels of PCBs remain in the Indian atmosphere. •Existing emission inventories cannot explain the high PCB concentrations in Indian atmosphere. •Electronic waste recycling, ship dismantling and open burning of municipal solid waste are implicated as potential sources. -- Measurement of atmospheric Polychlorinated biphenyls in seven major Indian cities

  3. A Single Rod Multi-modality Multi-interface Level Sensor Using an AC Current Source

    Directory of Open Access Journals (Sweden)

    Abdulgader Hwili

    2008-05-01

    Full Text Available Crude oil separation is an important process in the oil industry. To make efficient use of the separators, it is important to know their internal behaviour, and to measure the levels of multi-interfaces between different materials, such as gas-foam, foam-oil, oil-emulsion, emulsion-water and water-solids. A single-rod multi-modality multi-interface level sensor is presented, which has a current source, and electromagnetic modalities. Some key issues have been addressed, including the effect of salt content and temperature i.e. conductivity on the measurement.

  4. A thermoelectric-conversion power supply system using a strontium heat source of high-level radioactive nuclear waste

    International Nuclear Information System (INIS)

    Chikazawa, Yoshitaka

    2011-01-01

    A thermoelectric-conversion power supply system with radioactive strontium in high-level radioactive waste has been proposed. A combination of Alkali Metal Thermo-Electric Conversion (AMTEC) and a strontium fluoride heat source can provide a compact and long-lived power supply system. A heat source design with strontium fluoride pin bundles with Hastelloy cladding and intermediate copper has been proposed. This design has taken heat transportation into consideration, and, in this regard, the feasibility has been confirmed by a three-dimensional thermal analysis using Star-CD code. This power supply system with an electric output of 1 MW can be arranged in a space of 50 m 2 and approximately 1.1 m height and can be operated for 15 years without refueling. This compact and long-lived power supply is suitable for powering sources for remote places and middle-sized ships. From the viewpoint of geological disposal of high-level waste, the proposed power supply system provides a financial base for strontium-cesium partitioning. That is, a combination of minor-actinide recycling and strontium-cesium partitioning can eliminate a large part of decay heat in high-level waste and thus can save much space for geological disposal. (author)

  5. Curing of polymer thermosets via click reactions and on demand processes

    Science.gov (United States)

    Brei, Mark Richard

    In the first project, an azide functional resin and tetra propargyl aromatic diamines were fabricated for use as a composite matrix. These systems take already established epoxy/amine matrices and functionalize them with click moieties. This allows lower temperatures to be used in the production of a thermoset part. These new systems yield many better mechanical properties than their epoxy/amine derivatives, but their Tgs are low in comparison. The second project investigates the characterization of a linear system based off of the above azide functional resin and a difunctional alkyne. Through selectively choosing catalyst, the linear system can show regioselectivity to either a 1,4-disubstituted triazole, or a 1,5-disubstituted triazole. Without the addition of catalyst, the system produces both triazoles in almost an equal ratio. The differently catalyzed systems were cured and then analyzed by 1H and 13C NMR to better understand the structure of the material. The third project builds off of the utility of the aforementioned azide/alkyne system and introduces an on-demand aspect to the curing of the thermoset. With the inclusion of copper(II) within the azide/alkyne system, UV light is able to catalyze said reaction and cure the material. It has been shown that the copper(II) loading levels can be extremely small, which helps in reducing the copper's effect on mechanical properties The fourth project takes a look at polysulfide-based sealants. These sealants are normally cured via an oxidative reaction. This project took thiol-terminated polysulfides and fabricated alkene-terminated polysulfides for use as a thiol-ene cured material. By changing the mechanism for cure, the polysulfide can be cured via UV light with the use of a photoinitiator within the thiol/alkene polysulfide matrix. The final chapter will focus on a characterization technique, MALDI-TOF, which was used to help characterize the above materials as well as many others. By using MALDI-TOF, the

  6. Electronic device increases threshold sensitivity and removes noise from FM communications receiver

    Science.gov (United States)

    Conrad, W. M.; Loch, F. J.

    1971-01-01

    Threshold extension device connected between demodulator output and filter output minimizes clicking noise. Device consists of click-eliminating signal transfer channel with follow-and-hold circuit and detector for sensing click impulses. Final output consists of signal plus low level noise without high amplitude impulses.

  7. Biofunctionalization on alkylated silicon substrate surfaces via "click" chemistry.

    Science.gov (United States)

    Qin, Guoting; Santos, Catherine; Zhang, Wen; Li, Yan; Kumar, Amit; Erasquin, Uriel J; Liu, Kai; Muradov, Pavel; Trautner, Barbara Wells; Cai, Chengzhi

    2010-11-24

    Biofunctionalization of silicon substrates is important to the development of silicon-based biosensors and devices. Compared to conventional organosiloxane films on silicon oxide intermediate layers, organic monolayers directly bound to the nonoxidized silicon substrates via Si-C bonds enhance the sensitivity of detection and the stability against hydrolytic cleavage. Such monolayers presenting a high density of terminal alkynyl groups for bioconjugation via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC, a "click" reaction) were reported. However, yields of the CuAAC reactions on these monolayer platforms were low. Also, the nonspecific adsorption of proteins on the resultant surfaces remained a major obstacle for many potential biological applications. Herein, we report a new type of "clickable" monolayers grown by selective, photoactivated surface hydrosilylation of α,ω-alkenynes, where the alkynyl terminal is protected with a trimethylgermanyl (TMG) group, on hydrogen-terminated silicon substrates. The TMG groups on the film are readily removed in aqueous solutions in the presence of Cu(I). Significantly, the degermanylation and the subsequent CuAAC reaction with various azides could be combined into a single step in good yields. Thus, oligo(ethylene glycol) (OEG) with an azido tag was attached to the TMG-alkyne surfaces, leading to OEG-terminated surfaces that reduced the nonspecific adsorption of protein (fibrinogen) by >98%. The CuAAC reaction could be performed in microarray format to generate arrays of mannose and biotin with varied densities on the protein-resistant OEG background. We also demonstrated that the monolayer platform could be functionalized with mannose for highly specific capturing of living targets (Escherichia coli expressing fimbriae) onto the silicon substrates.

  8. An icon that everyone wants to click on : an empirical study on the relationship between consumer perceptions and mobile game icon successfulness

    OpenAIRE

    Jylhä, Henrietta

    2017-01-01

    Mobile games market has been touted as the fastest growing gaming sector in the world. Every day thousands of new mobile games are published to join millions of others on app stores. The competition for top grossing mobile games is fierce, and the way a game is represented greatly contributes to its commercial success. When browsing for mobile games, consumers search for an icon they want to click on. However, most mobile games fail to engage consumers who browse past hundreds of icons on app...

  9. Gaussian Plume Model Parameters for Ground-Level and Elevated Sources Derived from the Atmospheric Diffusion Equation in the Neutral and Stable Conditions

    International Nuclear Information System (INIS)

    Essa, K.S.M.

    2009-01-01

    The analytical solution of the atmospheric diffusion equation for a point source gives the ground-level concentration profiles. It depends on the wind speed ua nd vertical dispersion coefficient σ z expressed by Pasquill power laws. Both σ z and u are functions of downwind distance, stability and source elevation, while for the ground-level emission u is constant. In the neutral and stable conditions, the Gaussian plume model and finite difference numerical methods with wind speed in power law and the vertical dispersion coefficient in exponential law are estimated. This work shows that the estimated ground-level concentrations of the Gaussian model for high-level source and numerical finite difference method are very match fit to the observed ground-level concentrations of the Gaussian model

  10. Energy balance of lactating primiparous sows as affected by feeding level and dietary energy source

    OpenAIRE

    Brand, van den, H.; Heetkamp, M.J.W.; Soede, N.M.; Schrama, J.W.; Kemp, B.

    2000-01-01

    The effects of feeding level and major dietary energy source used during lactation on sow milk composition, piglet body composition, and energy balance of sows were determined. During a 21-d lactation, 48 primiparous sows were fed either a Fat-rich (134.9 g/kg fat; 196.8 g/kg carbohydrate) or a Starch-rich (33.2 g/kg fat; 380.9 g/kg carbohydrate) diet at either a High (44 MJ NE/d; 1,050 g protein/d) or a Low (33 MJ NE/d; 790 g protein/d) feeding level. Within each feeding level, the two diets...

  11. 7-Chloroquinolinotriazoles: synthesis by the azide-alkyne cycloaddition click chemistry, antimalarial activity, cytotoxicity and SAR studies.

    Science.gov (United States)

    Pereira, Guilherme R; Brandão, Geraldo Célio; Arantes, Lucas M; de Oliveira, Háliton A; de Paula, Renata Cristina; do Nascimento, Maria Fernanda A; dos Santos, Fábio M; da Rocha, Ramon K; Lopes, Júlio César D; de Oliveira, Alaíde Braga

    2014-02-12

    Twenty-seven 7-chloroquinolinotriazole derivatives with different substituents in the triazole moiety were synthesized via copper-catalyzed cycloaddition (CuAAC) click chemistry between 4-azido-7-chloroquinoline and several alkynes. All the synthetic compounds were evaluated for their in vitro activity against Plasmodium falciparum (W2) and cytotoxicity to Hep G2A16 cells. All the products disclosed low cytotoxicity (CC50 > 100 μM) and five of them have shown moderate antimalarial activity (IC50 from 9.6 to 40.9 μM). As chloroquine analogs it was expected that these compounds might inhibit the heme polymerization and SAR studies were performed aiming to explain their antimalarial profile. New structural variations can be designed on the basis of the results obtained. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  12. Identification of Sex Pheromones and Sex Pheromone Mimics for Two North American Click Beetle Species (Coleoptera: Elateridae) in the Genus Cardiophorus Esch.

    Science.gov (United States)

    Serrano, Jacqueline M; Collignon, R Maxwell; Zou, Yunfan; Millar, Jocelyn G

    2018-04-01

    To date, all known or suspected pheromones of click beetles (Coleoptera: Elateridae) have been identified solely from species native to Europe and Asia; reports of identifications from North American species dating from the 1970s have since proven to be incorrect. While conducting bioassays of pheromones of a longhorned beetle (Coleoptera: Cerambycidae), we serendipitously discovered that males of Cardiophorus tenebrosus L. and Cardiophorus edwardsi Horn were specifically attracted to the cerambycid pheromone fuscumol acetate, (E)-6,10-dimethylundeca-5,9-dien-2-yl acetate, suggesting that this compound might also be a sex pheromone for the two Cardiophorus species. Further field bioassays and electrophysiological assays with the enantiomers of fuscumol acetate determined that males were specifically attracted by the (R)-enantiomer. However, subsequent analyses of extracts of volatiles from female C. tenebrosus and C. edwardsi showed that the females actually produced a different compound, which was identified as (3R,6E)-3,7,11-trimethyl-6,10-dodecadienoic acid methyl ester (methyl (3R,6E)-2,3-dihydrofarnesoate). In field trials, both the racemate and the (R)-enantiomer of the pheromone attracted similar numbers of male beetles, suggesting that the (S)-enantiomer was not interfering with responses to the insect-produced (R)-enantiomer. This report constitutes the first conclusive identification of sex pheromones for any North American click beetle species. Possible reasons for the strong and specific attraction of males to fuscumol acetate, which is markedly different in structure to the actual pheromone, are discussed.

  13. Iodine-129 in Snow and Seawater in the Antarctic: Level and Source

    DEFF Research Database (Denmark)

    Xing, Shan; Hou, Xiaolin; Aldahan, Ala

    2015-01-01

    Anthropogenic 129I has been released to the environment in different ways and chemical species by human nuclear activities since the 1940s. These sources provide ideal tools to trace the dispersion of volatile pollutants in the atmosphere. Snow and seawater samples collected in Bellingshausen...... sites in the Southern Hemisphere. This feature indicates that 129I in Antarctic snow mainly originates from atmospheric nuclear weapons testing from 1945 to 1980; resuspension and re-emission of the fallout 129I in the Southern Hemisphere maintains the 129I level in the Antarctic atmosphere. 129I...

  14. Mitigation of Flicker using STATCOM with Three-Level 12-pulse Voltage Source Inverter

    OpenAIRE

    Ali Z a'fari

    2011-01-01

    Voltage flicker is a disturbance in electrical power systems. The reason for this disturbance is mainly the large nonlinear loads such as electric arc furnaces. Synchronous static compensator (STATCOM) is considered as a proper technique to mitigate the voltage flicker. Application of more suitable and precise power electronic converter leads to a more precise performance of the compensator. In this paper a three-level 12-pulse voltage source inverter (VSI) with a 12-term...

  15. Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

    Science.gov (United States)

    Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

    2016-08-01

    This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

  16. Knee-clicks and visual traits indicate fighting ability in eland antelopes: multiple messages and back-up signals

    DEFF Research Database (Denmark)

    Bro-Jørgensen, Jakob; Dabelsteen, Torben

    2008-01-01

    frequency of the knee-clicking sound honestly indicated body size, a main determinant of fighting ability. In contrast, the dewlap size increased with estimated age rather than body size, suggesting that, by magnifying the silhouette of older bulls disproportionately, the dewlap acts as an indicator of age......Background: Given the costs of signalling, why do males often advertise their fighting ability to rivals using several signals rather than just one? Multiple signalling theories have developed largely in studies of sexual signals, and less is known about their applicability to intra-sexual...... agonistic signals in eland reflect three separate components of fighting ability: (1) body size, (2) age and (3) presumably androgen-related aggression, which is reflected in three backup signals. The study highlights how complex agonistic signalling systems can evolve through the simultaneous action...

  17. [Arsenic levels in drinking water supplies from underground sources in the community of Madrid].

    Science.gov (United States)

    Aragonés Sanz, N; Palacios Diez, M; Avello de Miguel, A; Gómez Rodríguez, P; Martínez Cortés, M; Rodríguez Bernabeu, M J

    2001-01-01

    In 1998, arsenic concentrations of more than 50 micrograms/l were detected in some drinking water supplies from underground sources in the Autonomous Community of Madrid, which is the maximum permissible concentration for drinking water in Spain. These two facts have meant the getting under way of a specific plan for monitoring arsenic in the drinking water in the Autonomous Community of Madrid. The results of the first two sampling processes conducted in the arsenic level monitoring plan set out are presented. In the initial phase, water samples from 353 water supplies comprised within the census of the Public Health Administration of the Autonomous Community of Madrid were analyzed. A water supply risk classification was made based on these initial results. In a second phase, six months later, the analyses were repeated on those 35 water supplies which were considered to possibly pose a risk to public health. Seventy-four percent (74%) of the water supplies studied in the initial phase were revealed to have an arsenic concentration of less than 10 micrograms/l, 22.6% containing levels of 10 micrograms/l-50 micrograms/l, and 3.7% over 50 micrograms/l. Most of the water supplies showing arsenic levels of more than 10 micrograms/l are located in the same geographical area. In the second sampling process (six months later), the 35 water supplies classified as posing a risk were included. Twenty-six (26) of these supplies were revealed to have the same arsenic level ((10-50 micrograms/l), and nine changed category, six of which had less than 10 micrograms/l and three more than 50 micrograms/l. In the Autonomous Community of Madrid, less than 2% of the population drinks water coming from supplies which are from underground sources. The regular water quality monitoring conducted by the Public Health Administration has led to detecting the presence of more than 50 micrograms/l of arsenic in sixteen drinking water supplies from underground sources, which is the maximum

  18. Click functionalization of phenyl-capped bithiophene on azide-terminated self-assembled monolayers

    International Nuclear Information System (INIS)

    Zheng, Yijun; Cui, Jiaxi; Ikeda, Taichi

    2015-01-01

    Graphical abstract: - Highlights: • Electrochemically-active self-assembled monolayers with phenyl-capped bithiophene were prepared. • Post-functionalization method based on click chemistry solved the solubility issue of phenyl-capped thiophene alkanethiol. • The capture and release of the counter anions during the redox reaction were detectable by E-QCM. - Abstract: We immobilized tetra(ethylene glycol)-substituted phenyl-capped bithiophene with alkyne terminals (Ph2TPh-alkyne) on azide-terminated self-assembled monolayers (N 3 -SAMs) by Cu-catalyzed azide-alkyne cycloaddition reaction. Ph2TPh-functionalized SAMs on a gold substrate showed reversible electrochemical response. The surface densities of the azide groups in N 3 -SAMs and Ph2TPh units in Ph2TPh-functionalized SAMs were estimated to be 7.3 ± 0.3 × 10 −10 mol cm −2 and 4.6 ± 0.3 × 10 −10 mol cm −2 , respectively, by quartz crystal microbalance (QCM). Most of Ph2TPh-alkynes are considered to be anchored on N 3 -SAMs via both terminal groups. Ph2TPh-functionalized SAMs exhibited reversible redox peaks in cyclic voltammetry (CV). In redox reaction, reversible capture and release of the counter anion could be monitored by electrochemical QCM (E-QCM).

  19. Click functionalization of phenyl-capped bithiophene on azide-terminated self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yijun; Cui, Jiaxi [Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, Mainz 55128 (Germany); Ikeda, Taichi, E-mail: IKEDA.Taichi@nims.go.jp [Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, Mainz 55128 (Germany); Polymer Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-11-15

    Graphical abstract: - Highlights: • Electrochemically-active self-assembled monolayers with phenyl-capped bithiophene were prepared. • Post-functionalization method based on click chemistry solved the solubility issue of phenyl-capped thiophene alkanethiol. • The capture and release of the counter anions during the redox reaction were detectable by E-QCM. - Abstract: We immobilized tetra(ethylene glycol)-substituted phenyl-capped bithiophene with alkyne terminals (Ph2TPh-alkyne) on azide-terminated self-assembled monolayers (N{sub 3}-SAMs) by Cu-catalyzed azide-alkyne cycloaddition reaction. Ph2TPh-functionalized SAMs on a gold substrate showed reversible electrochemical response. The surface densities of the azide groups in N{sub 3}-SAMs and Ph2TPh units in Ph2TPh-functionalized SAMs were estimated to be 7.3 ± 0.3 × 10{sup −10} mol cm{sup −2} and 4.6 ± 0.3 × 10{sup −10} mol cm{sup −2}, respectively, by quartz crystal microbalance (QCM). Most of Ph2TPh-alkynes are considered to be anchored on N{sub 3}-SAMs via both terminal groups. Ph2TPh-functionalized SAMs exhibited reversible redox peaks in cyclic voltammetry (CV). In redox reaction, reversible capture and release of the counter anion could be monitored by electrochemical QCM (E-QCM).

  20. Double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor.

    Science.gov (United States)

    Qi, Honglan; Li, Min; Zhang, Rui; Dong, Manman; Ling, Chen

    2013-08-20

    A double electrochemical covalent coupling method based on click chemistry and diazonium chemistry for the fabrication of sensitive amperometric immunosensor was developed. As a proof-of-concept, a designed alkyne functionalized human IgG was used as a capture antibody and a HRP-labeled rabbit anti-goat IgG was used as signal antibody for the determination of the anti-human IgG using the sandwich model. The immunosensor was fabricated by electrochemically grafting a phenylazide on the surface of a glassy carbon electrode, and then, by coupling the alkyne functionalized human IgG with the phenylazide group through an electro-click chemistry in the presence of Cu(II). The amperometric measurement for the determination of the anti-human IgG was performed after the fabricated immunosensor was incubated with the target anti-human IgG and then with the HRP-labeled anti-goat IgG at -0.25V in 0.10M PBS (pH 7.0) containing 0.1mM hydroquinone and 2.0mM H2O2. The results showed that the increased current was linear with the logarithm of the concentration of the anti-human IgG in the range from 1.0×10(-10)g mL(-1) to 1.0×10(-8)g mL(-1) with a detection limit of 3×10(-11)g mL(-1). Furthermore, the feasibility of the double electrochemical covalent coupling method proposed in this work for fabricating the amperometric immunosensor array was explored. This work demonstrates that the double electrochemical covalent coupling method is a promising approach for the fabrication of the immunosensor and immunosensor array. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Identification of immiscible NAPL contaminant sources in aquifers by a modified two-level saturation based imperialist competitive algorithm

    Science.gov (United States)

    Ghafouri, H. R.; Mosharaf-Dehkordi, M.; Afzalan, B.

    2017-07-01

    A simulation-optimization model is proposed for identifying the characteristics of local immiscible NAPL contaminant sources inside aquifers. This model employs the UTCHEM 9.0 software as its simulator for solving the governing equations associated with the multi-phase flow in porous media. As the optimization model, a novel two-level saturation based Imperialist Competitive Algorithm (ICA) is proposed to estimate the parameters of contaminant sources. The first level consists of three parallel independent ICAs and plays as a pre-conditioner for the second level which is a single modified ICA. The ICA in the second level is modified by dividing each country into a number of provinces (smaller parts). Similar to countries in the classical ICA, these provinces are optimized by the assimilation, competition, and revolution steps in the ICA. To increase the diversity of populations, a new approach named knock the base method is proposed. The performance and accuracy of the simulation-optimization model is assessed by solving a set of two and three-dimensional problems considering the effects of different parameters such as the grid size, rock heterogeneity and designated monitoring networks. The obtained numerical results indicate that using this simulation-optimization model provides accurate results at a less number of iterations when compared with the model employing the classical one-level ICA. A model is proposed to identify characteristics of immiscible NAPL contaminant sources. The contaminant is immiscible in water and multi-phase flow is simulated. The model is a multi-level saturation-based optimization algorithm based on ICA. Each answer string in second level is divided into a set of provinces. Each ICA is modified by incorporating a new knock the base model.

  2. Transport-level description of the 252Cf-source method using the Langevin technique

    International Nuclear Information System (INIS)

    Stolle, A.M.; Akcasu, A.Z.

    1991-01-01

    The fluctuations in the neutron number density and detector outputs in a nuclear reactor can be analyzed conveniently by using the Langevin equation approach. This approach can be implemented at any level of approximation to describe the time evolution of the neutron population, from the most complete transport-level description to the very basic point reactor analysis of neutron number density fluctuations. In this summary, the complete space- and velocity-dependent transport-level formulation of the Langevin equation approach is applied to the analysis of the 252 Cf-source-driven noise analysis (CSDNA) method, an experimental technique developed by J.T. Mihalczo at Oak Ridge National Laboratory, which makes use of noise analysis to determine the reactivity of subcritical media. From this analysis, a theoretical expression for the subcritical multiplication factor is obtained that can then be used to interpret the experimental data. Results at the transport level are in complete agreement with an independent derivation performed by Sutton and Doub, who used the probability density method to interpret the CSDNA experiment, but differed from other expressions that have appeared in the literature

  3. Large-scale separation of single-walled carbon nanotubes by electronic type using click chemistry

    Science.gov (United States)

    Um, Jo-Eun; Song, Sun Gu; Yoo, Pil J.; Song, Changsik; Kim, Woo-Jae

    2018-01-01

    Single-walled carbon nanotubes (SWCNTs) can be either metallic or semiconducting, making their separation critical for applications in nanoelectronics, biomedical materials, and solar cells. Herein, we investigate a novel solution-phase separation method based on click chemistry (azide-alkyne Huisgen cycloaddition) and determine its efficiency and scalability. In this method, metallic SWCNTs in metallic/semiconducting SWCNT mixtures are selectively functionalized with alkyne groups by being reacted with 4-propargyloxybenezenediazonium tetrafluoroborate. Subsequently, silica nanoparticles are functionalized with azide groups and reacted with alkyne-bearing metallic SWCNTs in the SWCNT mixture in the presence of a Cu catalyst. As a result, metallic SWCNTs are anchored on silica powder, whereas non-functionalized semiconducting SWCNTs remain in solution. Low-speed centrifugation effectively removes the silica powder with attached metallic SWCNTs, furnishing a solution of highly pure semiconducting SWCNTs, as confirmed by Raman and UV-vis/near-infrared absorption measurements. This novel separation scheme exhibits the advantage of simultaneously separating both metallic and semiconducting SWCNTs from their mixtures, being cost-effective and therefore applicable at an industrial scale.

  4. The application of click chemistry in the synthesis of agents with anticancer activity

    Directory of Open Access Journals (Sweden)

    Ma N

    2015-03-01

    Full Text Available Nan Ma,1–3 Ying Wang,3 Bing-Xin Zhao,3 Wen-Cai Ye,1,3 Sheng Jiang2 1Department of Natural Medicinal Chemistry, China Pharmaceutical University, Nanjing, 2Laboratory of Medicinal Chemistry, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, 3Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, People’s Republic of China Abstract: The copper(I-catalyzed 1,3-dipolar cycloaddition between alkynes and azides (click chemistry to form 1,2,3-triazoles is the most popular reaction due to its reliability, specificity, and biocompatibility. This reaction has the potential to shorten procedures, and render more efficient lead identification and optimization procedures in medicinal chemistry, which is a powerful modular synthetic approach toward the assembly of new molecular entities and has been applied in anticancer drugs discovery increasingly. The present review focuses mainly on the applications of this reaction in the field of synthesis of agents with anticancer activity, which are divided into four groups: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, and antimicrotubule agents. Keywords: topoisomerase II inhibitors, histone deacetylase inhibitors, protein tyrosine kinase inhibitors, antimicrotubule agents

  5. Common basis of establishing safety standards and other safety decision-making levels for different sources of health risk

    International Nuclear Information System (INIS)

    Demin, V.F.

    2002-01-01

    Current approaches in establishing safety standards and other decision-making levels for different sources of health risk are critically analysed. To have a common basis for this decision-making a specific risk index R is recommended. In the common sense R is quantitatively defined as LLE caused by the annual exposure to the risk source considered: R = annual exposure, damage (LLE) from the exposure unit. This common definition is also rewritten in specific forms for a set of different risk sources (ionising radiation, chemical pollutants, etc): for different risk sources the exposure can be measured with different quantities (the probability of death, the exposure dose, etc.). R is relative LLE: LLE in years referred to 1 year under the risk. The dimension of this value is [year/year]. In the statistical sense R is conditionally the share of the year, which is lost due to exposure to a risk source during this year. In this sense R can be called as the relative damage. Really lifetime years are lost after the exposure. R can be in some conditional sense considered as a dimensionless quantity. General safety standards R n for the public and occupational workers have been suggested in terms of this index: R n = 0.0007 and 0.01 accordingly. Secondary safety standards are derived for a number of risk sources (ionising radiation, environmental chemical pollutants, etc). Values of R n are chosen in such a way that to have the secondary radiation BSS being equivalent to the current one's. Other general and derived levels for safety decision-making are also proposed including the de-minimus levels. Their possible dependence on the national or regional health-demographic data (HDD) is considered. Such issues as the ways of the integration and averaging of risk indices considered through the national or regional HDD for different risk sources and the use of non-threshold linear exposure - response relationships for ionising radiation and chemical pollutants are analysed

  6. Use of the Drawing-Writing Technique to Determine the Level of Knowledge of Pre-Service Teachers Regarding Renewable Energy Sources

    Science.gov (United States)

    Kara, Filiz

    2015-01-01

    The aim of this study was to determine the level of knowledge of pre-service science teachers in Turkey regarding the different types of renewable energy sources, the methods used for obtaining energy from these sources, and the areas of use for these energy sources. Within the context of the study, the drawing-writing technique was used in order…

  7. Using level-I PRA for enhanced safety of the advanced neutron source reactor

    International Nuclear Information System (INIS)

    Ramsey, C.T.; Linn, M.A.

    1995-01-01

    The phase-1, level-I probabilistic risk assessment (PRA) of the Advanced Neutron Source (ANS) reactor has been completed as part of the conceptual design phase of this proposed research facility. Since project inception, PRA and reliability concepts have been an integral part of the design evolutions contributing to many of the safety features in the current design. The level-I PRA has been used to evaluate the internal events core damage frequency against project goals and to identify systems important to safety and availability, and it will continue to guide and provide support to accident analysis, both severe and nonsevere. The results also reflect the risk value of defense-in-depth safety features in reducing the likelihood of core damage

  8. Energy balance of lactating primiparous sows as affected by feeding level and dietary energy source

    NARCIS (Netherlands)

    Brand, van den H.; Heetkamp, M.J.W.; Soede, N.M.; Schrama, J.W.; Kemp, B.

    2000-01-01

    The effects of feeding level and major dietary energy source used during lactation on sow milk composition, piglet body composition, and energy balance of sows were determined. During a 21-d lactation, 48 primiparous sows were fed either a Fat-rich (134.9 g/kg fat; 196.8 g/kg carbohydrate) or a

  9. THE RELATIONSHIP BETWEEN THE SOURCES OF PSYCHOLOGICAL STRESS AND THE LEVEL OF SELF-ESTEEM AMONG FOOTBALL REFEREES

    OpenAIRE

    Charbi Belkacem,; Khader Salih

    2018-01-01

    This survey aims at revealing the relationship of sources of psychological stress to the level of self-esteem. It focused mainly on the following questions: Is there a correlation between fear of physical abuse and self-esteem? Is there a correlation between rewards, incentives, and self-esteem? Is there a correlation between conflict of social dimension and level of self-esteem? Is there a correlation between media dimension and level of self-esteem? Is there a correlat...

  10. Association between information sources and level of knowledge about diabetes in patients with type 2 diabetes.

    Science.gov (United States)

    Cántaro, Katherine; Jara, Jimena A; Taboada, Marco; Mayta-Tristán, Percy

    2016-05-01

    To evaluate the association between the type of information source and the level of knowledge about diabetes mellitus in patients with type 2 diabetes. A cross-sectional study was conducted at a reference diabetes and hypertension center in Lima, Peru, during 2014. Level of knowledge was measured using the Diabetes Knowledge Questionnaire-24 and 12 information sources. Patients with 75% correct answers were considered to have a good knowledge. Adjusted odds ratios were calculated. Of the total 464 patients enrolled, 52.2% were females, and 20.3% used the Internet as information source. Mean knowledge was 12.9±4.8, and only 17.0% had a good knowledge, which was associated with information on diabetes obtained from the Internet (OR=2.03, 95% CI 1.32 to 3.14), and also from other patients (OR=1.99, 95% CI 1.20 to 3.31). Good knowledge was also associated with postgraduate education (OR=3.66, 95% CI 1.21 to 11.09), disease duration longer than 12 years (OR=1.91, 95% CI 1,22 to 3.01), and age older than 70 years (OR=0.39, 95% CI 0.21-0.72). Search for information in the Internet was positively associated to a good level of knowledge. It is suggested to teach patients with diabetes to seek information on the Internet and, on the other hand, to develop virtual spaces for interaction of patients with diabetes. Copyright © 2016 SEEN. Published by Elsevier España, S.L.U. All rights reserved.

  11. Porovnání Pay per Click systémů na příkladě realizované reklamní kampaně

    OpenAIRE

    Krejčí, Jiří

    2009-01-01

    The aim of this thesis is to present advertising on the internet with the main focus on the following questions: what are the most important forms and what are the current and future trends in the advertising business industry. The main objective of this thesis is to compare different systems of Pay per click on the Czech internet in terms of their performance. Testing PPC system, an ad campaign for the company Kremo was created. This ad campaign was run on three major web sites which are ava...

  12. Open-Source Python Modules to Estimate Level Ice Thickness from Ice Charts

    Science.gov (United States)

    Geiger, C. A.; Deliberty, T. L.; Bernstein, E. R.; Helfrich, S.

    2012-12-01

    A collaborative research effort between the University of Delaware (UD) and National Ice Center (NIC) addresses the task of providing open-source translations of sea ice stage-of-development into level ice thickness estimates on a 4km grid for the Interactive Multisensor Snow and Ice Mapping System (IMS). The characteristics for stage-of-development are quantified from remote sensing imagery with estimates of level ice thickness categories originating from World Meteorological Organization (WMO) egg coded ice charts codified since the 1970s. Conversions utilize Python scripting modules which transform electronic ice charts with WMO egg code characteristics into five level ice thickness categories, in centimeters, (0-10, 10-30, 30-70, 70-120, >120cm) and five ice types (open water, first year pack ice, fast ice, multiyear ice, and glacial ice with a reserve slot for deformed ice fractions). Both level ice thickness categories and ice concentration fractions are reported with uncertainties propagated based on WMO ice stage ranges which serve as proxy estimates for standard deviation. These products are in preparation for use by NCEP, CMC, and NAVO by 2014 based on their modeling requirements for daily products in near-real time. In addition to development, continuing research tests the value of these estimated products against in situ observations to improve both value and uncertainty estimates.

  13. Synthesis of amphiphilic poly(ε-caprolactone)-b-poly( N-vinylcaprolactam) block copolymers via the combination of RAFT polymerization and click chemistry

    International Nuclear Information System (INIS)

    Assis, Paulo Henrique; Aguiar, Graziele Aparecida de Jesus; Moraes, Rodolfo Minto de; Medeiros, Simone de Fatima; Santos, Amilton Martins

    2016-01-01

    Full text: In recent years, well-defined block copolymers composed of a hydrophilic and hydrophobic segments have gained much interest as drug carriers, because of their enhanced solubility and sustained release of the drug in controlled delivery systems [1]. The development of strategies to obtain block copolymers has attracted considerable attention, due to the possibility to combine characteristic properties of the homopolymers. A wide variety of well-defined block copolymers have been successfully synthesized by combining the efficiency and selectivity of click chemistry with the powerful RAFT polymerization mechanism. In the present work, well-defined amphiphilic, biocompatible, partially biodegradable, and thermosensitive poly(ε-caprolactone)-b-poly(N-vinylcaprolactam) (PCL-b-PNVCL) block copolymers were synthesized by combining ring opening polymerization (ROP), reversible addition-fragmentation chain transfer (RAFT) polymerization and subsequent click chemistry reaction. Alkyne-terminated poly(ε-caprolactone) (alkyne-PCL) was obtained by the ring opening polymerization of ε-caprolactone (ε-CL) using propargyl alcohol as initiator and stannous-2-ethylhexanoate [Sn(Oct) 2 ] as catalyst. The azide end-capped-poly(N-vinylcaprolactam) (PNVCL-N 3 ) was synthesized by reversible addition-fragmentation chain transfer/macromolecular design via interchange of xanthates (RAFT/MADIX) polymerization of the N-vinylcaprolactam (NVCL) mediated by a novel chain transfer agent comprising an azide function , 2-azidoethyl[(ethoxycarbonothioyl)thio](phenyl)acetate. These functionalized homopolymers, alkyne-PCL and PNVCL-N 3 , were coupled by the 1,3 dipolar cycloaddition reaction in order to obtain the corresponding block copolymers. These (co)polymers were characterized by FTIR, 1 H NMR and GPC measurements. Reference: 1. RAMESH, K., SINGH, S., MITRA, K., CHATTOPADHYAY, D., MISRA, N., & RAY, B. (2015). Colloid and Polymer Science, 1-9. (author)

  14. Two-dimensional transport of dust from an infinite line source at ground level: non-zero roughness height

    International Nuclear Information System (INIS)

    Hassan, M.H.A.; Eltayeb, I.A.

    1992-07-01

    The previous study (Eltayeb and Hassan, 1992) of the two-dimensional diffusion equation of dust over a rough ground surface, which acts as a dust source of variable strength, under the influence of horizontal wind and gravitational attraction is here extended to all finite values of the roughness height Z 0 . An analytic expression is obtained for the concentration of dust for a general strength of the source. The result reduces to the previously known solutions as special cases. The expression for the concentration has been evaluated for some representative example of the source strength g(X). It is found that the concentration decreases with roughness height at any fixed point above ground level. (author). 4 refs, 2 figs

  15. Effects of dietary carbohydrate sources on plasma glucose, insulin and IGF-I levels in multiparous sows

    NARCIS (Netherlands)

    Wientjes, J.G.M.; Soede, N.M.; Aarsse, F.; Laurenssen, B.F.A.; Koopmanschap, R.E.; Brand, van den H.; Kemp, B.

    2012-01-01

    Effects of different carbohydrate sources on plasma glucose, insulin and insulin-like growth factor-I (IGF-I) levels were compared to subsequently be able to study effects of insulin-stimulating diets on follicle development in sows. The following feed components were tested in 12 sows during six

  16. Effects of Heterogeneity and Uncertainties in Sources and Initial and Boundary Conditions on Spatiotemporal Variations of Groundwater Levels

    Science.gov (United States)

    Zhang, Y. K.; Liang, X.

    2014-12-01

    Effects of aquifer heterogeneity and uncertainties in source/sink, and initial and boundary conditions in a groundwater flow model on the spatiotemporal variations of groundwater level, h(x,t), were investigated. Analytical solutions for the variance and covariance of h(x, t) in an unconfined aquifer described by a linearized Boussinesq equation with a white noise source/sink and a random transmissivity field were derived. It was found that in a typical aquifer the error in h(x,t) in early time is mainly caused by the random initial condition and the error reduces as time goes to reach a constant error in later time. The duration during which the effect of the random initial condition is significant may last a few hundred days in most aquifers. The constant error in groundwater in later time is due to the combined effects of the uncertain source/sink and flux boundary: the closer to the flux boundary, the larger the error. The error caused by the uncertain head boundary is limited in a narrow zone near the boundary but it remains more or less constant over time. The effect of the heterogeneity is to increase the variation of groundwater level and the maximum effect occurs close to the constant head boundary because of the linear mean hydraulic gradient. The correlation of groundwater level decreases with temporal interval and spatial distance. In addition, the heterogeneity enhances the correlation of groundwater level, especially at larger time intervals and small spatial distances.

  17. THE Low-level Radio Frequency System for the superconducting cavities of National Synchrotron Light Source II

    International Nuclear Information System (INIS)

    Ma, H.; Rose, J.; Holub, B.; Cupolo, J.; Oliva, J.; Sikora, R.; Yeddulla, M.

    2011-01-01

    A digital low-level radio frequency (LLRF) field controller has been developed for the storage ring of The National Synchrotron Light Source-II (NSLS-II). The primary performance goal for the LLRF is to support the required RF operation of the superconducting cavities with a beam current of 500mA and a 0.14 degree or better RF phase stability. The digital field controller is FPGA-based, in a standard format 19-inch/I-U chassis. It has an option of high-level control support with MATLAB running on a local host computer through a USB2.0 port. The field controller has been field tested with the high-power superconducting RF (SRF) at Canadian light Source, and successfully stored a high beam current of 250 mA. The test results show that required specifications for the cavity RF field stability are met. This digital field controller is also currently being used as a development platform for other functional modules in the NSLS-II RF systems.

  18. Towards source level evaluation of the evidential value of fibre examinations.

    Science.gov (United States)

    Vooijs, Cees; Vergeer, Peter; van der Weerd, Jaap

    2015-05-01

    This paper aims to provide the first steps towards a numerical source level evaluation of fibre evidence. For that purpose, likelihood ratio equations are derived for four generic scenarios, in which the source frequency, the number of references and trace types investigated, and the number of matches vary. Previous experimental studies into the evaluation of fibre evidence are reviewed and we demonstrate how the results of these studies, as well as other data, can be used to evaluate the derived equations for the four scenarios. Evaluation is not straightforward and requires a number of assumptions. This is mainly because the relevant population under consideration in a specific case cannot be sufficiently evaluated. In addition, the subjective match-criterion in current forensic fibre examinations makes it impossible to implement a good evaluation of the within-variation of samples. As a result, the discrimination power, currently calculated for discrimination studies, is only valid for samples with negligible heterogeneity. We conclude that reporting a numerical evidential value for forensic fibre examinations is not yet feasible as the data are available for only a few types of fibres and cannot be used without several assumptions. We propose a number of developments that are required to improve the accuracy and numerical analysis. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  19. Sources and levels of ambient ocean sound near the Antarctic Peninsula.

    Directory of Open Access Journals (Sweden)

    Robert P Dziak

    Full Text Available Arrays of hydrophones were deployed within the Bransfield Strait and Scotia Sea (Antarctic Peninsula region from 2005 to 2009 to record ambient ocean sound at frequencies of up to 125 and 500 Hz. Icequakes, which are broadband, short duration signals derived from fracturing of large free-floating icebergs, are a prominent feature of the ocean soundscape. Icequake activity peaks during austral summer and is minimum during winter, likely following freeze-thaw cycles. Iceberg grounding and rapid disintegration also releases significant acoustic energy, equivalent to large-scale geophysical events. Overall ambient sound levels can be as much as ~10-20 dB higher in the open, deep ocean of the Scotia Sea compared to the relatively shallow Bransfield Strait. Noise levels become lowest during the austral winter, as sea-ice cover suppresses wind and wave noise. Ambient noise levels are highest during austral spring and summer, as surface noise, ice cracking and biological activity intensifies. Vocalizations of blue (Balaenoptera musculus and fin (B. physalus whales also dominate the long-term spectra records in the 15-28 and 89 Hz bands. Blue whale call energy is a maximum during austral summer-fall in the Drake Passage and Bransfield Strait when ambient noise levels are a maximum and sea-ice cover is a minimum. Fin whale vocalizations were also most common during austral summer-early fall months in both the Bransfield Strait and Scotia Sea. The hydrophone data overall do not show sustained anthropogenic sources (ships and airguns, likely due to low coastal traffic and the typically rough weather and sea conditions of the Southern Ocean.

  20. Chemical surface reactions by click chemistry: coumarin dye modification of 11-bromoundecyltrichlorosilane monolayers

    International Nuclear Information System (INIS)

    Haensch, Claudia; Hoeppener, Stephanie; Schubert, Ulrich S

    2008-01-01

    The functionalization of surfaces and the ability to tailor their properties with desired physico-chemical functions is an important field of research with a broad spectrum of applications. These applications range from the modification of wetting properties, over the alteration of optical properties, to the fabrication of molecular electronic devices. In each of these fields, it is of specific importance to be able to control the quality of the layers with high precision. The present study demonstrates an approach that utilizes the 1,3-dipolar cycloaddition of terminal acetylenes to prepare triazole-terminated monolayers on different substrates. The characterization of the precursor monolayers, the optimization of the chemical surface reactions as well as the clicking of a fluorescent dye molecule on such azide-terminated monolayers was carried out. A coumarin 343 derivative was utilized to discuss the aspects of the functionalization approach. Based on this approach, a number of potential surface reactions, facilitated via the acetylene-substituted functional molecules, for a broad range of applications is at hand, thus leading to numerous possibilities where surface modifications are concerned. These modifications can be applied on non-structured surfaces of silicon or glass or can be used on structured surfaces. Various possibilities are discussed

  1. DNA-modified electrodes fabricated using copper-free click chemistry for enhanced protein detection.

    Science.gov (United States)

    Furst, Ariel L; Hill, Michael G; Barton, Jacqueline K

    2013-12-31

    A method of DNA monolayer formation has been developed using copper-free click chemistry that yields enhanced surface homogeneity and enables variation in the amount of DNA assembled; extremely low-density DNA monolayers, with as little as 5% of the monolayer being DNA, have been formed. These DNA-modified electrodes (DMEs) were characterized visually, with AFM, and electrochemically, and were found to facilitate DNA-mediated reduction of a distally bound redox probe. These low-density monolayers were found to be more homogeneous than traditional thiol-modified DNA monolayers, with greater helix accessibility through an increased surface area-to-volume ratio. Protein binding efficiency of the transcriptional activator TATA-binding protein (TBP) was also investigated on these surfaces and compared to that on DNA monolayers formed with standard thiol-modified DNA. Our low-density monolayers were found to be extremely sensitive to TBP binding, with a signal decrease in excess of 75% for 150 nM protein. This protein was detectable at 4 nM, on the order of its dissociation constant, with our low-density monolayers. The improved DNA helix accessibility and sensitivity of our low-density DNA monolayers to TBP binding reflects the general utility of this method of DNA monolayer formation for DNA-based electrochemical sensor development.

  2. Synthesis and evaluation of functional alginate hydrogels based on click chemistry for drug delivery applications.

    Science.gov (United States)

    García-Astrain, Clara; Avérous, Luc

    2018-06-15

    Environment-sensitive alginate-based hydrogels for drug delivery applications are receiving increasing attention. However, most work in this field involves traditional cross-linking strategies which led to hydrogels with poor long-term stability. Herein, a series of chemically cross-linked alginate hydrogels was synthesized via click chemistry using Diels-Alder reaction by reacting furan-modified alginate and bifunctional cross-linkers. Alginate was successfully functionalized with furfurylamine. Then, 3D architectures were synthesized with water-soluble bismaleimides. Different substitution degrees were achieved in order to study the effect of alginate modification and the cross-linking extent over the behaviour of the hydrogels. The ensuing hydrogels were analysed in terms of microstructure, swelling, structure modification and rheological behaviour. The materials response to external stimuli such as pH was also investigated, revealing a pulsatile behaviour in a large pH range (1-13) and a clear pH-dependent swelling. Finally, vanillin release studies were conducted to demonstrate the potential of these biobased materials for drug delivery applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Estimation of sources and factors affecting indoor VOC levels using basic numerical methods

    Directory of Open Access Journals (Sweden)

    Sibel Mentese

    2016-11-01

    Full Text Available Volatile Organic Compounds (VOCs are a concern due to their adverse health effects and extensive usage. Levels of indoor VOCs were measured in six homes located in three different towns in Çanakkale, Turkey. Monthly indoor VOC samples were collected by passive sampling throughout a year. The highest levels of total volatile organic compounds (TVOC, benzene, toluene, and xylenes occurred in industrial, rural, and urban sites in a descending order. VOC levels were categorized as average values annually, during the heating period, and non-heating period. Several building/environmental factors together with occupants’ habits were scored to obtain a basic indoor air pollution index (IAPi for the homes. Bivariate regression analysis was applied to find the associations between the pollutant levels and home scores. IAPi scores were found to be correlated with average indoor VOC levels. In particular, very strong associations were found for occupants’ habits. Furthermore, observed indoor VOC levels were categorized by using self-organizing map (SOM and two simple scoring approaches, rounded average and maximum value methods, to classify the indoor environments based on their VOC compositions (IAPvoc. Three classes were used for both IAPi and IAPvoc approaches, namely “good”, “moderate”, and “bad”. There is an urgent need for indexing studies to determine the potential sources and/or factors affecting observed VOCs. This study gives a basic but good start for further studies.

  4. Skyline: an open source document editor for creating and analyzing targeted proteomics experiments.

    Science.gov (United States)

    MacLean, Brendan; Tomazela, Daniela M; Shulman, Nicholas; Chambers, Matthew; Finney, Gregory L; Frewen, Barbara; Kern, Randall; Tabb, David L; Liebler, Daniel C; MacCoss, Michael J

    2010-04-01

    Skyline is a Windows client application for targeted proteomics method creation and quantitative data analysis. It is open source and freely available for academic and commercial use. The Skyline user interface simplifies the development of mass spectrometer methods and the analysis of data from targeted proteomics experiments performed using selected reaction monitoring (SRM). Skyline supports using and creating MS/MS spectral libraries from a wide variety of sources to choose SRM filters and verify results based on previously observed ion trap data. Skyline exports transition lists to and imports the native output files from Agilent, Applied Biosystems, Thermo Fisher Scientific and Waters triple quadrupole instruments, seamlessly connecting mass spectrometer output back to the experimental design document. The fast and compact Skyline file format is easily shared, even for experiments requiring many sample injections. A rich array of graphs displays results and provides powerful tools for inspecting data integrity as data are acquired, helping instrument operators to identify problems early. The Skyline dynamic report designer exports tabular data from the Skyline document model for in-depth analysis with common statistical tools. Single-click, self-updating web installation is available at http://proteome.gs.washington.edu/software/skyline. This web site also provides access to instructional videos, a support board, an issues list and a link to the source code project.

  5. Impact of level and source of compost based organic material on the productivity of autumn maize (zea mays l.)

    International Nuclear Information System (INIS)

    Iqbal, S.; Khan, H.Z.; Ehsanullah, A.

    2014-01-01

    Organic manure from different sources could be an effective substitute of chemical fertilizers. Therefore, the present study compares the effect of varying level (0, 2, 4, 6, 8, 10 t ha/sup -1/) of two types of compost, i.e poultry manure compost (PM compost) and press-mud compost (PrM compost) on the yield of maize. The experiment was conducted at Agronomic Research Area, University of Agriculture Faisalabad, Pakistan for two consecutive years 2011 and 2012. Results of this study revealed that all the levels and sources of compost based organic material had significant effect on the yield and yield parameters of autumn maize. Maximum plant height, cob diameter, cob length, cob weight, number of grain rows per cob, number of grains per cob, 1000-grain weight biological yield, grain yield and harvest index were produced by the application of 10 t ha/sup -1/ PM compost. Whereas, the number of cobs per plant was not significantly affected by level and source of compost based organic material. It was concluded that 10 t ha/sup -1/ PM compost could be used lucratively for optimizing maize yield. (author)

  6. Modeling Effectiveness of Gradual Increases in Source Level to Mitigate Effects of Sonar on Marine Mammals

    NARCIS (Netherlands)

    Benda-Beckmann, A.M. von; Wensveen, P.J.; Kvadsheim, P.H.; Lam, F.P.A.; Miller, P.J.O.; Tyack, P.L.; Ainslie, M.A.

    2013-01-01

    Ramp-up or soft-start procedures (i.e., gradual increase in the source level) are used to mitigate the effect of sonar sound on marine mammals, although no one to date has tested whether ramp-up procedures are effective at reducing the effect of sound on marine mammals. We investigated the

  7. Teachers’ Opinions in Relation to School Principals’ Organizational Power Sources andAuthentic Leadership Levels

    OpenAIRE

    NARTGÜN, Şenay Sezgin; NARTGÜN, Zekeriya; ARICI, Uzman Deniz

    2016-01-01

    The aim of this study is to determine the organizational power sources that used and authentic leadership levels that demonstrated by primary, secondary and high school principals within the framework of teachers‟ opinions. In the study, comparative survey was used. One hundred and twenty teachers of primary, secondary and high schools located at Dörtdivan and Seben provinces of Bolu are consist the working group of this study. The data gathered from the one hundred teachers whom are particip...

  8. Strain-promoted copper free click chemistry for 64Cu radiolabeling of integrin-αvβ6 targeted peptide

    International Nuclear Information System (INIS)

    Satpati, Drishty; Bauer, Nadine; Hausner, Sven H.; Sutcliffe, Julie L.

    2014-01-01

    Strain promoted copper free click chemistry offers a fast and efficient method for preparation of radio labeled molecular probes and pre-targeted imaging in vivo. The fast reaction kinetics, driven by the release of strain energy ranging from 10-19 kcal/mol for cyclooctynes, precludes the need for toxic copper catalyst for chemical ligation between alkynes and azides. In particular this catalyst free approach provides a favorable platform for synthesis of radiometalated probes requiring macrocycle chelates for formation of stable and kinetically inert complexes where Cu(I) can interfere with metal chelates. In present studies DOTA-ADIBO (azadibenzocyclooctyne amine), a strained chelate-alkyne system has been constructed for bioconjugation with the azide-modified PEGylated peptide, N 3 -Ala-PEG 28 -A20FMDV2 and radiolabeled with ( 64 Cu) Cu for assessment as a integrin-α v β 6 , targeting molecular probe

  9. Synthesis of unsymmetric bipyridine-Pt(II) -alkynyl complexes through post-click reaction with emission enhancement characteristics and their applications as phosphorescent organic light-emitting diodes.

    Science.gov (United States)

    Li, Yongguang; Tsang, Daniel Ping-Kuen; Chan, Carmen Ka-Man; Wong, Keith Man-Chung; Chan, Mei-Yee; Yam, Vivian Wing-Wah

    2014-10-13

    Two unsymmetric bipyridine-platinum(II)-alkynyl complexes have been synthesised by a post-click reaction. These metal complexes are found to exhibit emission enhancement properties. The photoluminescence quantum yield can be significantly increased from 0.03 in solution to 0.72 in solid-state thin films. Efficient solution-processable organic light-emitting diodes have been fabricated by utilizing these complexes as phosphorescent dopants. A high external quantum efficiency of up to 5.8% has been achieved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Synthesis of a Nanostructured Composite: Octakis(1-propyl-1H-1,2,3-triazole-4-yl(methyl 2-chlorobenzoate))octasilsesquioxane via Click Reaction.

    Science.gov (United States)

    Ghodsi, Mohammadi Ziarani; Shakiba Nahad, Monireh; Lashgari, Negar; Alireza, Badiei

    2015-01-01

    Octakis(1-propyl-1H-1,2,3-triazole-4-yl(methyl 2-chlorobenzoate))octasilsesquioxanes as functionalized silsesquioxanes were synthesized via click reaction (copper-catalyzed Huisgen 1,3-dipolar cycloaddition reaction) between azidemoiety functionalized silsesquioxane and prop-2-ynyl 2-chlorobenzoate. The latter one was synthesized via the condensation reaction of propargyl alcohol and 2-chlorobenzoyl chloride in the presence of SBA-Pr-NH(2) (Santa Barbara Amorphous type material) as a nano basic catalyst. This approach provides a simple and convenient route to efficiently functionalize a wide range of new structures on the surface of silsesquioxanes.

  11. Echolocation in the Risso's dolphin, Grampus griseus

    Science.gov (United States)

    Philips, Jennifer D.; Nachtigall, Paul E.; Au, Whitlow W. L.; Pawloski, Jeffrey L.; Roitblat, Herbert L.

    2003-01-01

    The Risso's dolphin (Grampus griseus) is an exclusively cephalopod-consuming delphinid with a distinctive vertical indentation along its forehead. To investigate whether or not the species echolocates, a female Risso's dolphin was trained to discriminate an aluminum cylinder from a nylon sphere (experiment 1) or an aluminum sphere (experiment 2) while wearing eyecups and free swimming in an open-water pen in Kaneohe Bay, Hawaii. The dolphin completed the task with little difficulty despite being blindfolded. Clicks emitted by the dolphin were acquired at average amplitudes of 192.6 dB re 1 μPa, with estimated sources levels up to 216 dB re 1 μPa-1 m. Clicks were acquired with peak frequencies as high as 104.7 kHz (Mfp=47.9 kHz), center frequencies as high as 85.7 kHz (Mf0=56.5 kHz), 3-dB bandwidths up to 94.1 kHz (MBW=39.7 kHz), and root-mean-square bandwidths up to 32.8 kHz (MRMS=23.3 kHz). Click durations were between 40 and 70 μs. The data establish that the Risso's dolphin echolocates, and that, aside from slightly lower amplitudes and frequencies, the clicks emitted by the dolphin were similar to those emitted by other echolocating odontocetes. The particular acoustic and behavioral findings in the study are discussed with respect to the possible direction of the sonar transmission beam of the species.

  12. Low levels of H2S may replace sulfate as sulfur source in sulfate-deprived onion

    NARCIS (Netherlands)

    Durenkamp, Mark; De Kok, LJ

    2005-01-01

    Onion (Allium cepa L.) was exposed to low levels of H2S in order to investigate to what extent H2S could be used as a sulfur source for growth under sulfate-deprived conditions. Sulfate deprivation for a two-week period resulted in a decreased biomass production of the shoot, a subsequently

  13. Measurements on low level plutonium sources using Rad Elec Electret Ion Chambers

    International Nuclear Information System (INIS)

    Levinskas, D.; Teagarden, J.; Wilkes, E.

    1998-01-01

    This is a technique for measuring gross alpha particle emission from interior contaminated surfaces. The technique utilizes electret ionization chambers (EICs), which consist of a charged Teflon plate (the electret) and an electrically-conductive plastic chamber of 145 ml volume. To measure very low levels of alpha contamination, the EIC is left in place on the surface to be measured for about 48 hours. The change in the surface charge of the electret is a measure of the ionization during the measurement period. The rate of change of the charge is converted into an activity using an appropriate calibration factor. This system has the ability to make accurate gross alpha contamination measurements while being subject to a high airborne radon concentration, such as might occur in certain buildings or during an atmospheric inversion. Previous studies of the effectiveness of these EIC's focused on levels of alpha contamination much higher than is allowed for unrestricted release of material at the Rocky Flats Environmental Technology Site (RFETS). This study evaluated the performance of EIC's at levels from 100 disintegrations per minute (dpm) per 100 cm 2 to below 20 dpm per 100 cm 2 (all measurements are referenced to a 4π geometry). The EIC's were found to be within 5% accuracy, as compared to a gas flow proportional counter calibrated with a NIST-traceable source. Test results indicate that the EIC, left in place for 48 hours, can detect alpha contamination as low as 6.4 ± 3.0 dpm/100 cm 2 to a 95% confidence level

  14. Southern Dobrogea coastal potable water sources and Upper Quaternary Black Sea level changes

    Science.gov (United States)

    Caraivan, Glicherie; Stefanescu, Diana

    2013-04-01

    Southern Dobrogea is a typical geologic platform unit, placed in the south-eastern part of Romania, with a Pre-Cambrian crystalline basement and a Paleozoic - Quaternary sedimentary cover. It is bordered to the north by the Capidava - Ovidiu fault and by the Black Sea to the east. A regional WNW - ESE and NNE - SSW fault system divides the Southern Dobrogea structure in several tectonic blocks. Four drinking water sources have been identified: surface water, phreatic water, medium depth Sarmatian aquifer, and deep Upper Jurassic - Lower Cretaceous aquifer. Surface water sources are represented by several springs emerged from the base of the loess cliff, and a few small rivers, barred by coastal beaches. The phreatic aquifer develops at the base of the loess deposits, on the impervious red clay, overlapping the Sarmatian limestones. The medium depth aquifer is located in the altered and karstified Sarmatian limestones, and discharges into the Black Sea. The Sarmatian aquifer is unconfined where covered by silty loess deposits, and locally confined, where capped by clayey loess deposits. The aquifer is supplied from the Pre-Balkan Plateau. The Deep Upper Jurassic - Lower Cretaceous aquifer, located in the limestone and dolomite deposits, is generally confined and affected by the regional WNW - ESE and NNE - SSW fault system. In the south-eastern Dobrogea, the deep aquifer complex is separated from the Sarmatian aquifer by a Senonian aquitard (chalk and marls). The natural boundary of the Upper Jurassic - Lower Cretaceous aquifer is the Capidava - Ovidiu Fault. The piezometric heads show that the Upper Jurassic - Lower Cretaceous aquifer is supplied from the Bulgarian territory, where the Upper Jurassic deposits crop out. The aquifer discharges into the Black Sea to the east and into Lake Siutghiol to the northeast. The cyclic Upper Quaternary climate changes induced drastic remodeling of the Black Sea level and the corresponding shorelines. During the Last Glacial

  15. Renewable energy, coal as a baseload power source, and greenhouse gas emissions: Evidence from U.S. state-level data

    International Nuclear Information System (INIS)

    Squalli, Jay

    2017-01-01

    This paper examines the relationship between renewable energy production and greenhouse gas emissions (GHG) using U.S. state-level data for 2010. After controlling for other sources of emissions, U.S. states that produce a larger share of renewable energy are found to have lower GHG emissions. It is estimated that a 10% increase in the share of renewable energy could decrease CH_4 emissions by about 0.26%. Since the use of renewable energy sources does not release GHG emissions, this effect can be interpreted as stabilizing if renewable energy is added to coal use or as corrective if it replaces coal. After accounting for the role of coal as a baseload power source, an increase in the share of renewable energy is estimated to mitigate N_2O emissions at the U.S. state level only if states individually decrease their share of coal use to levels below 41.47%. These findings have significant policy implications for the provision of guidance to policymakers in identifying optimal energy mixes and in pursuing realistic goals to enhance renewable energy penetration and to contribute to the current efforts of tackling climate change. - Highlights: • The paper examines the link between renewable energy, coal, and GHG emissions. • The analysis accounts for the role of coal as a baseload power source. • A 10% increase in renewable energy share decreases CH_4 emissions by about 0.26%. • Renewable energy can mitigate emissions if the share of coal drops below 41.47%.

  16. The mechanics of unrest at Long Valley caldera, California: 1. Modeling the geometry of the source using GPS, leveling and two-color EDM data

    Science.gov (United States)

    Battaglia, Maurizio; Segall, P.; Murray, J.; Cervelli, Peter; Langbein, J.

    2003-01-01

    We surveyed 44 existing leveling monuments in Long Valley caldera in July 1999, using dual frequency global positioning system (GPS) receivers. We have been able to tie GPS and leveling to a common reference frame in the Long Valley area and computed the vertical deformation by differencing GPS-based and leveled orthometric heights. The resurgent dome uplifted 74??7 cm from 1975 to 1999. To define the inflation source, we invert two-color EDM and uplift data from the 1985-1999 unrest period using spherical or ellipsoidal sources. We find that the ellipsoidal source satisfies both the vertical and horizontal deformation data, whereas the spherical point source cannot. According to our analysis of the 1985-1999 data, the main source of deformation is a prolate ellipsoid located beneath the resurgent dome at a depth of 5.9 km (95% bounds of 4.9-7.5 km). This body is vertically elongated, has an aspect ratio of 0.475 (95% bounds are 0.25-0.65) and a volume change of 0.086 km3 (95% bounds are 0.06-0.13 km3). Failure to account for the ellipsoidal nature of the source biases the estimated source depth by 2.1 km (35%), and the source volume by 0.038 km3 (44%). ?? 2003 Elsevier B.V. All rights reserved.

  17. Effects of source and level of dietary energy supplementation on in vitro digestibility and methane production from tall fescue-based diets

    Science.gov (United States)

    There is a lack of information about the effect of different sources, levels, and the mixtures of energy supplements commonly fed to cattle grazing tall fescue. Therefore, the objective of this study was to evaluate different common energy sources for beef cattle grazing tall fescue using an in vitr...

  18. Uranium recovery from low-level aqueous sources

    International Nuclear Information System (INIS)

    Kelmers, A.D.; Goeller, H.E.

    1981-03-01

    The aqueous sources of soluble uranium were surveyed and evaluated in terms of the uranium geochemical cycle in an effort to identify potential unexploited resources. Freshwater sources appeared to be too low in uranium content to merit consideration, while seawater, although very dilute (approx. 3.3 ppB), contains approx. 4 x 10 9 metric tons of uranium in all the world's oceans. A literature review of recent publications and patents concerning uranium recovery from seawater was conducted. Considerable experimental work is currently under way in Japan; less is being done in the European countries. An assessment of the current state of technology is presented in this report. Repeated screening programs have identified hydrous titanium oxide as the most promising candidate absorbent. However, some of its properties such as distribution coefficient, selectivity, loading, and possibly stability appear to render its use inadequate in a practical recovery system. Also, various assessments of the energy efficiency of pumped or tidal power schemes for contacting the sorbent and seawater are in major disagreement. Needed future research and development tasks are discussed. A fundamental sorbent development program to greatly improve sorbent properties would be required to permit practical recovery of uranium from seawater. Major unresolved engineering aspects of such recovery systems are also identified and discussed

  19. Synthesis and preliminary evaluation of novel 99mTc-labeled folate derivative via click reaction for SPECT imaging

    International Nuclear Information System (INIS)

    Guo, Zhide; Zhang, Pu; Song, Manli; Wu, Xiaowei; Liu, Chang; Zhao, Zuoquan; Lu, Jie; Zhang, Xianzhong

    2014-01-01

    The folate receptor is over expressed in a wide variety of human tumors. In this study, a novel 99m Tc-labeled folate derivative ( 99m Tc-HYNIC-T-FA) was synthesized as a potential FR-targeting imaging probe and its efficiency was evaluated. This 99m Tc-complex could be obtained through practical manner and showed improved in vivo characteristics compared with other radiofolates. Thus, this novel 99m Tc-HYNIC-T-FA compound could serve as a potential imaging agent for folate receptor positive tumors. - Highlights: • An efficient synthetic strategy (click chemistry) was used to improve the overall efficiency. • 99m Tc-HYNIC-T-FA showed a high tumor uptake but low no-target tissues uptakes. • Excellent tumor-to-kidney ratio was achieved by injecting PMX. • A kit formulation was developed to obtain the desired product without any purification

  20. The Design and Performance of the Spallation Neutron Source Low-Level RF Control System

    CERN Document Server

    Champion, M; Kasemir, K; Ma, H; Piller, C

    2004-01-01

    The Spallation Neutron Source linear accelerator low-level RF control system has been developed within a collaboration of Lawrence Berkeley, Los Alamos, and Oak Ridge national laboratories. Three distinct generations of the system, described in a previous publication [1], have been used to support beam commissioning at Oak Ridge. The third generation system went into production in early 2004, with installation in the coupled-cavity and superconducting linacs to span the remainder of the year. The final design of this system will be presented along with results of performance measurements.

  1. A New Approach for Mobile Advertising Click-Through Rate Estimation Based on Deep Belief Nets.

    Science.gov (United States)

    Chen, Jie-Hao; Zhao, Zi-Qian; Shi, Ji-Yun; Zhao, Chong

    2017-01-01

    In recent years, with the rapid development of mobile Internet and its business applications, mobile advertising Click-Through Rate (CTR) estimation has become a hot research direction in the field of computational advertising, which is used to achieve accurate advertisement delivery for the best benefits in the three-side game between media, advertisers, and audiences. Current research on the estimation of CTR mainly uses the methods and models of machine learning, such as linear model or recommendation algorithms. However, most of these methods are insufficient to extract the data features and cannot reflect the nonlinear relationship between different features. In order to solve these problems, we propose a new model based on Deep Belief Nets to predict the CTR of mobile advertising, which combines together the powerful data representation and feature extraction capability of Deep Belief Nets, with the advantage of simplicity of traditional Logistic Regression models. Based on the training dataset with the information of over 40 million mobile advertisements during a period of 10 days, our experiments show that our new model has better estimation accuracy than the classic Logistic Regression (LR) model by 5.57% and Support Vector Regression (SVR) model by 5.80%.

  2. Synthesis and optical properties of pyrrolidinyl peptide nucleic acid carrying a clicked Nile red label

    Directory of Open Access Journals (Sweden)

    Nattawut Yotapan

    2014-09-01

    Full Text Available DNA or its analogues with an environment-sensitive fluorescent label are potentially useful as a probe for studying the structure and dynamics of nucleic acids. In this work, pyrrolidinyl peptide nucleic acid (acpcPNA was labeled at its backbone with Nile red, a solvatochromic benzophenoxazine dye, by means of click chemistry. The optical properties of the Nile red-labeled acpcPNA were investigated by UV–vis and fluorescence spectroscopy in the absence and in the presence of DNA. In contrast to the usual quenching observed in Nile red-labeled DNA, the hybridization with DNA resulted in blue shifting and an enhanced fluorescence regardless of the neighboring bases. More pronounced blue shifts and fluorescence enhancements were observed when the DNA target carried a base insertion in close proximity to the Nile red label. The results indicate that the Nile red label is located in a more hydrophobic environment in acpcPNA–DNA duplexes than in the single-stranded acpcPNA. The different fluorescence properties of the acpcPNA hybrids of complementary DNA and DNA carrying a base insertion are suggestive of different interactions between the Nile red label and the duplexes.

  3. A New Approach for Mobile Advertising Click-Through Rate Estimation Based on Deep Belief Nets

    Science.gov (United States)

    Zhao, Zi-Qian; Shi, Ji-Yun; Zhao, Chong

    2017-01-01

    In recent years, with the rapid development of mobile Internet and its business applications, mobile advertising Click-Through Rate (CTR) estimation has become a hot research direction in the field of computational advertising, which is used to achieve accurate advertisement delivery for the best benefits in the three-side game between media, advertisers, and audiences. Current research on the estimation of CTR mainly uses the methods and models of machine learning, such as linear model or recommendation algorithms. However, most of these methods are insufficient to extract the data features and cannot reflect the nonlinear relationship between different features. In order to solve these problems, we propose a new model based on Deep Belief Nets to predict the CTR of mobile advertising, which combines together the powerful data representation and feature extraction capability of Deep Belief Nets, with the advantage of simplicity of traditional Logistic Regression models. Based on the training dataset with the information of over 40 million mobile advertisements during a period of 10 days, our experiments show that our new model has better estimation accuracy than the classic Logistic Regression (LR) model by 5.57% and Support Vector Regression (SVR) model by 5.80%. PMID:29209363

  4. Sustainable thermoplastic elastomers derived from cellulose, fatty acid and furfural via ATRP and click chemistry.

    Science.gov (United States)

    Yu, Juan; Lu, Chuanwei; Wang, Chunpeng; Wang, Jifu; Fan, Yimin; Chu, Fuxiang

    2017-11-15

    Cellulose-based thermoplastic elastomers (TPEs) have attracted considerable attention because of their rigid backbone, good mechanical properties, renewable nature and abundance. In the present study, sustainable TPEs based on ethyl cellulose (EC), fatty acid and furfural were generated by the combination of ATRP and "click chemistry". To fabricate sustainable TPEs with higher toughness, a range of polymers, including mono random-copolymer poly(tetrahydrofurfuryl methacrylate-co-lauryl methacrylate) (P(THFMA-co-LMA), dual polymer side chains PTHFMA and PLMA, and mono-block copolymer PTHFMA-b-PLMA, were designed as side chains to fabricate EC brush copolymers with random, dual or block side chain architectures using the "grafting from" and "grafting onto" methods. The multi-armed structures, chemical compositions and phase separation of these EC brush copolymers were confirmed by FT-IR, 1 H NMR, GPC, DSC, TEM and SEM. Overall, three types of EC brush copolymers all exhibited the desired mechanical properties of TPEs. In addition, the EC brush copolymers with dual/block side chain architectures showed higher tensile strength than that of the random polymers with similar compositions. Copyright © 2017. Published by Elsevier Ltd.

  5. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles

    Science.gov (United States)

    Sarwar, Atif; Katas, Haliza; Samsudin, Siti Noradila; Zin, Noraziah Mohamad

    2015-01-01

    Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP) and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC) of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene) triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide) triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68) demonstrated the safety; suggesting that these derivatives could be used in future

  6. [Transfer characteristic and source identification of soil heavy metals from water-level-fluctuating zone along Xiangxi River, three-Gorges Reservoir area].

    Science.gov (United States)

    Xu, Tao; Wang, Fei; Guo, Qiang; Nie, Xiao-Qian; Huang, Ying-Ping; Chen, Jun

    2014-04-01

    Transfer characteristics of heavy metals and their evaluation of potential risk were studied based on determining concentration of heavy metal in soils from water-level-fluctuating zone (altitude:145-175 m) and bank (altitude: 175-185 m) along Xiangxi River, Three Gorges Reservoir area. Factor analysis-multiple linear regression (FA-MLR) was employed for heavy metal source identification and source apportionment. Results demonstrate that, during exposing season, the concentration of soil heavy metals in water-level-fluctuation zone and bank showed the variation, and the concentration of soil heavy metals reduced in shallow soil, but increased in deep soil at water-level-fluctuation zone. However, the concentration of soil heavy metals reduced in both shallow and deep soil at bank during the same period. According to the geoaccumulation index,the pollution extent of heavy metals followed the order: Cd > Pb > Cu > Cr, Cd is the primary pollutant. FA and FA-MLR reveal that in soils from water-level-fluctuation zone, 75.60% of Pb originates from traffic, 62.03% of Cd is from agriculture, 64.71% of Cu and 75.36% of Cr are from natural rock. In soils from bank, 82.26% of Pb originates from traffic, 68.63% of Cd is from agriculture, 65.72% of Cu and 69.33% of Cr are from natural rock. In conclusion, FA-MLR can successfully identify source of heavy metal and compute source apportionment of heavy metals, meanwhile the transfer characteristic is revealed. All these information can be a reference for heavy metal pollution control.

  7. Noise annoyance from stationary sources: Relationships with exposure metric day-evening-night level (DENL) and their confidence intervals

    NARCIS (Netherlands)

    Miedema, H.M.E.; Vos, H.

    2004-01-01

    Relationships between exposure to noise [metric: day-evening-night levels (DENL)] from stationary sources (shunting yards, a seasonal industry, and other industries) and annoyance are presented. Curves are presented for expected annoyance score, the percentage "highly annoyed" (%HA, cutoff at 72 on

  8. Multilevel Converter by Cascading Two-Level Three-Phase Voltage Source Converter

    Directory of Open Access Journals (Sweden)

    Abdullrahman A. Al-Shamma’a

    2018-04-01

    Full Text Available This paper proposes a topology using isolated, cascaded multilevel voltage source converters (VSCs and employing two-winding magnetic elements for high-power applications. The proposed topology synthesizes 6 two-level, three-phase VSCs, so the power capability of the presented converter is six times the capability of each VSC module. The characteristics of the proposed topology are demonstrated through analyzing its current relationships, voltage relationships and power capability in detail. The power rating is equally shared among the VSC modules without the need for a sharing algorithm; thus, the converter operates as a single three-phase VSC. The comparative analysis with classical neutral-point clamped, flying capacitor and cascaded H-bridge exhibits the superior features of fewer insulated gate bipolar transistors (IGBTs, capacitor requirement and fewer diodes. To validate the theoretical performance of the proposed converter, it is simulated in a MATLAB/Simulink environment and the results are experimentally demonstrated using a laboratory prototype.

  9. Low-level rf control of Spallation Neutron Source: System and characterization

    Directory of Open Access Journals (Sweden)

    Hengjie Ma

    2006-03-01

    Full Text Available The low-level rf control system currently commissioned throughout the Spallation Neutron Source (SNS LINAC evolved from three design iterations over 1 yr intensive research and development. Its digital hardware implementation is efficient, and has succeeded in achieving a minimum latency of less than 150 ns which is the key for accomplishing an all-digital feedback control for the full bandwidth. The control bandwidth is analyzed in frequency domain and characterized by testing its transient response. The hardware implementation also includes the provision of a time-shared input channel for a superior phase differential measurement between the cavity field and the reference. A companion cosimulation system for the digital hardware was developed to ensure a reliable long-term supportability. A large effort has also been made in the operation software development for the practical issues such as the process automations, cavity filling, beam loading compensation, and the cavity mechanical resonance suppression.

  10. Effect of graded levels and sources of protein on scrotal ...

    African Journals Online (AJOL)

    Iso caloric rations (10.50 MJ/kg DM ME) were formulated using non-conventional protein source (maize offal and dry layer litter) to contain 12.11% CP, 14.96% CP, and 17.94% CP and fed to groups A, B and C respectively. Another ration was formulated using conventional protein source (maize, wheat bran, groundnut ...

  11. [PHAHs levels in soil samples from the E-waste disassembly sites and their sources allocation].

    Science.gov (United States)

    Zhao, Gao-Feng; Wang, Zi-Jian

    2009-06-15

    Soil samples (each with 3 replicates of - 1 kg, at the top 0-5 cm layer) were collected from each of the e-waste disassembly sites and the control site. Also obtained from each disassembly site were samples (each weighing - 0.2 kg) of cable coating,stuffing powder, and circuit boards chipping. The contents of 23 PBB congeners, 12 PBDE congeners, and 27 PCB congeners in soil and in their potential sources, including e-waste residues, were measured using the GC-MS5975B technique. The highest level of PBBs was found in the cable coating among the three e-waste residues, with a concentration of 35.25 ng x g(-1). The contents of low-brominated PBBs (including monobromobiphenyls and dibromobiphenyls) accounted for 38% of the total PBBs concentration observed in cable coating sample. The highest levels of PBDEs and PBDE209 were found in the stuffing powder for electronic component among the collected e-waste residues, with a concentration of 29.71 and 4.19 x 10(3) ng x g(-1). PBDE153 and PBDE183 were the most predominant PBDE congeners, with their concentration accounting for 43% and 24% of the total PBDEs concentration observed in the stuffing powder sample, respectively. Levels of PCBs in cable coating were the highest in these e-waste residues, with a concentration of 680.02 ngx g(-1). The observed values of the three PHAHs in soils from the disassembly site were considerably higher than their corresponding values observed in the control site (p < 0.05), which indicates that these PHAHs from e-waste is the pollution source of local environment.

  12. Village-Level Identification of Nitrate Sources: Collaboration of Experts and Local Population in Benin, Africa

    Science.gov (United States)

    Crane, P.; Silliman, S. E.; Boukari, M.; Atoro, I.; Azonsi, F.

    2005-12-01

    Deteriorating groundwater quality, as represented by high nitrates, in the Colline province of Benin, West Africa was identified by the Benin national water agency, Direction Hydraulique. For unknown reasons the Colline province had consistently higher nitrate levels than any other region of the country. In an effort to address this water quality issue, a collaborative team was created that incorporated professionals from the Universite d'Abomey-Calavi (Benin), the University of Notre Dame (USA), Direction l'Hydraulique (a government water agency in Benin), Centre Afrika Obota (an educational NGO in Benin), and the local population of the village of Adourekoman. The goals of the project were to: (i) identify the source of nitrates, (ii) test field techniques for long term, local monitoring, and (iii) identify possible solutions to the high levels of groundwater nitrates. In order to accomplish these goals, the following methods were utilized: regional sampling of groundwater quality, field methods that allowed the local population to regularly monitor village groundwater quality, isotopic analysis, and sociological methods of surveys, focus groups, and observations. It is through the combination of these multi-disciplinary methods that all three goals were successfully addressed leading to preliminary identification of the sources of nitrates in the village of Adourekoman, confirmation of utility of field techniques, and initial assessment of possible solutions to the contamination problem.

  13. Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

    Energy Technology Data Exchange (ETDEWEB)

    Rodolfo Sosa, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Humberto Bravo, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico)], E-mail: hbravo@servidor.unam.mx; Violeta Mugica, A. [Universidad Autonoma Metropolitana, Azcapotzalco, D.F. (Mexico); Pablo Sanchez, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Emma Bueno, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia (Mexico); Krupa, Sagar [Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 (United States)

    2009-03-15

    Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City.

  14. Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

    International Nuclear Information System (INIS)

    Rodolfo Sosa, E.; Humberto Bravo, A.; Violeta Mugica, A.; Pablo Sanchez, A.; Emma Bueno, L.; Krupa, Sagar

    2009-01-01

    Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City

  15. Sensitivity analysis and benchmarking of the BLT low-level waste source term code

    International Nuclear Information System (INIS)

    Suen, C.J.; Sullivan, T.M.

    1993-07-01

    To evaluate the source term for low-level waste disposal, a comprehensive model had been developed and incorporated into a computer code, called BLT (Breach-Leach-Transport) Since the release of the original version, many new features and improvements had also been added to the Leach model of the code. This report consists of two different studies based on the new version of the BLT code: (1) a series of verification/sensitivity tests; and (2) benchmarking of the BLT code using field data. Based on the results of the verification/sensitivity tests, the authors concluded that the new version represents a significant improvement and it is capable of providing more realistic simulations of the leaching process. Benchmarking work was carried out to provide a reasonable level of confidence in the model predictions. In this study, the experimentally measured release curves for nitrate, technetium-99 and tritium from the saltstone lysimeters operated by Savannah River Laboratory were used. The model results are observed to be in general agreement with the experimental data, within the acceptable limits of uncertainty

  16. SystemC Transaction-Level Modeling of an MPSoC Platform Based on an Open Source ISS by Using Interprocess Communication

    Directory of Open Access Journals (Sweden)

    Sami Boukhechem

    2008-01-01

    Full Text Available Transaction-level modeling (TLM is a promising technique to deal with the increasing complexity of modern embedded systems. This model allows a system designer to model a complete application, composed of hardware and software parts, at several levels of abstraction. For this purpose, we use systemC, which is proposed as a standardized modeling language. This paper presents a transaction-level modeling cosimulation methodology for modeling, validating, and verifying our embedded open architecture platform. The proposed platform is an open source multiprocessor system-on-chip (MPSoC platform, integrated under the synthesis tool for adaptive and reconfigurable system-on-chip (STARSoC environment. It relies on the integration between an open source instruction set simulators (ISSs, OR1Ksim platform, and the systemC simulation environment which contains other components (wishbone bus, memories, …, etc.. The aim of this work is to provide designers with the possibility of faster and efficient architecture exploration at a higher level of abstractions, starting from an algorithmic description to implementation details.

  17. quanTLC, an online open-source solution for videodensitometric quantification.

    Science.gov (United States)

    Fichou, Dimitri; Morlock, Gertrud E

    2018-07-27

    The image is the key feature of planar chromatography. Videodensitometry by digital image conversion is the fastest way of its evaluation. Instead of scanning single sample tracks one after the other, only few clicks are needed to convert all tracks at one go. A minimalistic software was newly developed, termed quanTLC, that allowed the quantitative evaluation of samples in few minutes. quanTLC includes important assets such as open-source, online, free of charge, intuitive to use and tailored to planar chromatography, as none of the nine existent software for image evaluation covered these aspects altogether. quanTLC supports common image file formats for chromatogram upload. All necessary steps were included, i.e., videodensitogram extraction, preprocessing, automatic peak integration, calibration, statistical data analysis, reporting and data export. The default options for each step are suitable for most analyses while still being tunable, if needed. A one-minute video was recorded to serve as user manual. The software capabilities are shown on the example of a lipophilic dye mixture separation. The quantitative results were verified by comparison with those obtained by commercial videodensitometry software and opto-mechanical slit-scanning densitometry. The data can be exported at each step to be processed in further software, if required. The code was released open-source to be exploited even further. The software itself is online useable without installation and directly accessible at http://shinyapps.ernaehrung.uni-giessen.de/quanTLC. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Update: An efficient synthesis of poly(ethylene glycol)-supported iron(II) porphyrin using a click reaction and its application for the catalytic olefination of aldehydes

    KAUST Repository

    Chinnusamy, Tamilselvi R.

    2012-05-09

    The facile synthesis of polyethylene glycol (PEG)-immobilized iron(II) porphyrin using a copper-catalyzed azide-alkyne [3+2] cycloaddition "click" reaction is reported. The prepared complex 5 (PEG-C 51H 39FeN 7O) was found to be an efficient catalyst for the selective olefination of aldehydes with ethyl diazoacetate in the presence of triphenylphosphine, and afforded excellent olefin yields with high (E) selectivities. The PEG-supported catalyst 5 was readily recovered by precipitation and filtration, and was recycled through ten runs without significant activity loss. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Echolocation in sympatric Peale's dolphins (Lagenorhynchus australis) and Commerson's dolphins (Cephalorhynchus commersonii) producing narrow-bandhigh-frequency clicks

    DEFF Research Database (Denmark)

    Kyhn, Line Anker; Jensen, Frants Havmand; Beedholm, Kristian

    2010-01-01

    -element hydrophone array from wild Peale's (Lagenorhynchus australis) and Commerson's (Cephalorhynchus commersonii) dolphins off the Falkland Islands. The centroid frequency was different between Commerson's (133±2kHz) and Peale's (129±3kHz) dolphins. The r.m.s. bandwidth was 12±3kHz for both species. The source...... level was higher for Peale's dolphin (185±6dB re 1 uPa p.-p.) than for Commerson's(177±5 dB re 1 uPa p.-p.). The mean directivity indexes were 25dB for both species. The relatively low source levels in combination with the high directivity index may be an adaptation to reduce clutter when foraging...

  20. Application of ''Confirm tank T is an appropriate feed source for High-Level waste feed batch X'' to specific feed batches

    International Nuclear Information System (INIS)

    JO, J.

    1999-01-01

    This document addresses the characterization needs of tanks as set forth in the Data Quality Objectives for TWRS Privatization Phase I: Confirm Tank T is an Appropriate Feed Source for High-Level Waste Feed Batch X (Crawford et al. 1998). The primary purpose of this document is to collect existing data and identify the data needed to determine whether or not the feed source(s) are appropriate for a specific batch. To answer these questions, the existing tank data must be collected and a detailed review performed. If the existing data are insufficient to complete a full comparison, additional data must be obtained from the feed source(s). Additional information requirements need to be identified and formally documented, then the source tank waste must be sampled or resampled and analyzed. Once the additional data are obtained, the data shall be incorporated into the existing database for the source tank and a reevaluation of the data against the Data Quality Objective (DQO) must be made

  1. OSU-6: A Highly Efficient, Metal-Free, Heterogeneous Catalyst for the Click Synthesis of 5-Benzyl and 5-Aryl-1H-tetrazoles

    Directory of Open Access Journals (Sweden)

    Baskar Nammalwar

    2015-12-01

    Full Text Available OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the robust nature of the catalyst under the optimized reaction conditions. OSU-6 promotes the 1,3-dipolar addition of azides to nitriles without significant degradation or clogging of the nanoporous structure. The catalyst can be reused up to five times without a significant reduction in yield, and it does not require treatment with acid between reactions.

  2. Current Background Noise Sources and Levels in the NASA Ames 40- by 80-Foot Wind Tunnel: A Status Report

    Science.gov (United States)

    Allen, Christopher S.; Jaeger, Stephen; Soderman, Paul; Koga, Dennis (Technical Monitor)

    1999-01-01

    Background noise measurements were made of the acoustic environment in the National Full-Scale Aerodynamics Complex 40- by 80-Foot Wind Tunnel (40x80) at NASA Ames Research Center. The measurements were acquired subsequent to the 40x80 Aeroacoustic Modernization Project, which was undertaken to improve the anechoic characteristics of the 40x80's closed test section as well as reduce the levels of background noise in the facility. The resulting 40x80 anechoic environment was described by Soderman et. al., and the current paper describes the resulting 40x80 background noise, discusses the sources of the noise, and draws comparisons to previous 40x80 background noise levels measurements. At low wind speeds or low frequencies, the 40x80 background noise is dominated by the fan drive system. To obtain the lowest fan drive noise for a given tunnel condition, it is possible in the 40x80 to reduce the fans' rotational speed and adjust the fans' blade pitch, as described by Schmidtz et. al. This idea is not new, but has now been operationally implemented with modifications for increased power at low rotational speeds. At low to mid-frequencies and at higher wind speeds, the dominant noise mechanism was thought to be caused by the surface interface of the previous test section floor acoustic lining. In order to reduce this noise mechanism, the new test section floor lining was designed to resist the pumping of flow in and out of the space between the grating slats required to support heavy equipment. In addition, the lining/flow interface over the entire test section was designed to be smoother and quieter than the previous design. At high wind speeds or high frequencies, the dominant source of background noise in the 40x80 is believed to be caused by the response of the in-flow microphone probes (required by the nature of the closed test section) to the fluctuations in the freestream flow. The resulting background noise levels are also different for probes of various

  3. Synthesis of novel pyrazoline based bis (1,2,3-triazole scaffolds via click chemistry

    Directory of Open Access Journals (Sweden)

    Kiran Kothuri

    2017-01-01

    Full Text Available A series of novel bis(1,2,3-triazoles derivatives 7a–m were synthesized by the 1,3-dipolar cycloaddition (click-reaction of 1-methyl-3,5-bis(2- -(prop-2-yn-1-yloxyphenyl-4,5-dihydro-1H-pyrazole (5 with various aralkyl azides 6a–m in the presence of sodium ascorbate and copper sulphate with good yields. The required precursor 5 was synthesized by reacting (E-1,3- -bis(2-hydroxyphenylprop-2-en-1-one (3 with methylhydrazine hydrate via 2,2′-(1-methyl-4,5-dihydro-1H-pyrazole-3,5-diyldiphenol 4, followed by reaction with propargyl bromide. The homogeneity of all the newly synthesized compounds was checked by TLC. The IR, NMR, mass spectral data and elemental analysis were in accord with the assigned structure. The title compounds were evaluated for their antibacterial activity against various bacterial strains, i.e., Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis; compounds 7f–7h and 7j were found to be moderately active against the bacteria, when compared with that of the standard drug. Furthermore, the same library of compounds was evaluated for their antioxidant activity using the nitric oxide radical scavenging activity. The results of the study showed that compounds 7e–7h and 7k–7m showed good radical scavenging activity.

  4. Grafting of a peptide probe for Prostate-Specific Antigen detection using diazonium electroreduction and click chemistry.

    Science.gov (United States)

    Strzemińska, I; Sainte Rose Fanchine, S; Anquetin, G; Reisberg, S; Noël, V; Pham, M C; Piro, B

    2016-07-15

    The main objective of this work was to validate a label-free electrochemical method of protein detection using peptides as capture probes. As a proof-of-concept, we used a 7 amino acids sequence (HSSKLQL) specific for Prostate Specific Antigen. We investigated various electrografting conditions of two anilines (2-[(4-aminophenyl)sulfanyl]-8-hydroxy-1,4-naphthoquinone and 4-azidoaniline) further converted in situ into their corresponding diazonium salts on glassy carbon electrodes. It was demonstrated that the best method to obtain a mixed layer is the simultaneous electroreduction of the two diazonium salts. 4-azidoaniline was used to covalently immobilize the ethynyl-functionalized peptide probe by click coupling, and the hydroxynaphthoquinone derivative plays the role of electrochemical transducer of the peptide-protein recognition. The proteolytic activity of PSA towards a small peptide substrate carrying streptavidin at its distal end was also investigated to design an original sensing architecture leading to a reagentless, label free, and "signal-on" PSA sensor. Without optimization, the limit of quantification can be estimated in the nM to pM range. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Two discrete components of the 20 Hz steady-state response are distinguished through the modulation of activation level

    DEFF Research Database (Denmark)

    Griskova, Inga; Mørup, Morten; Parnas, Josef

    2009-01-01

    Objective: To investigate the modulation of amplitude and phase precision of the auditory steady-state response (SSR) to 20 Hz stimulation in two conditions varying in the level of activation. Methods: Click stimuli (20 Hz) were applied while subjects were sitting upright silently reading a book......-negative multi-way factorization (NMWF). Results: The NMWF decomposition of amplitude and phase precision measures resulted in the observation of two distinct components: a component at the frequency of stimulation – 20 Hz SSR and a component emerging at 40 Hz – 20 Hz SSR-related 40 Hz activity. Modulation...... by the activation level was observed only for 20 Hz SSR-related 40 Hz activity as increased amplitude and phase precision during low activation level. No such effects were observed for 20 Hz SSR. Conclusion: The discrete components of the 20 Hz SSR are distinguished through modulation of activation level, 20 Hz SSR...

  6. Quantitative Secretome Analysis of Activated Jurkat Cells Using Click Chemistry-Based Enrichment of Secreted Glycoproteins.

    Science.gov (United States)

    Witzke, Kathrin E; Rosowski, Kristin; Müller, Christian; Ahrens, Maike; Eisenacher, Martin; Megger, Dominik A; Knobloch, Jürgen; Koch, Andrea; Bracht, Thilo; Sitek, Barbara

    2017-01-06

    Quantitative secretome analyses are a high-performance tool for the discovery of physiological and pathophysiological changes in cellular processes. However, serum supplements in cell culture media limit secretome analyses, but serum depletion often leads to cell starvation and consequently biased results. To overcome these limiting factors, we investigated a model of T cell activation (Jurkat cells) and performed an approach for the selective enrichment of secreted proteins from conditioned medium utilizing metabolic marking of newly synthesized glycoproteins. Marked glycoproteins were labeled via bioorthogonal click chemistry and isolated by affinity purification. We assessed two labeling compounds conjugated with either biotin or desthiobiotin and the respective secretome fractions. 356 proteins were quantified using the biotin probe and 463 using desthiobiotin. 59 proteins were found differentially abundant (adjusted p-value ≤0.05, absolute fold change ≥1.5) between inactive and activated T cells using the biotin method and 86 using the desthiobiotin approach, with 31 mutual proteins cross-verified by independent experiments. Moreover, we analyzed the cellular proteome of the same model to demonstrate the benefit of secretome analyses and provide comprehensive data sets of both. 336 proteins (61.3%) were quantified exclusively in the secretome. Data are available via ProteomeXchange with identifier PXD004280.

  7. A New Approach for Mobile Advertising Click-Through Rate Estimation Based on Deep Belief Nets

    Directory of Open Access Journals (Sweden)

    Jie-Hao Chen

    2017-01-01

    Full Text Available In recent years, with the rapid development of mobile Internet and its business applications, mobile advertising Click-Through Rate (CTR estimation has become a hot research direction in the field of computational advertising, which is used to achieve accurate advertisement delivery for the best benefits in the three-side game between media, advertisers, and audiences. Current research on the estimation of CTR mainly uses the methods and models of machine learning, such as linear model or recommendation algorithms. However, most of these methods are insufficient to extract the data features and cannot reflect the nonlinear relationship between different features. In order to solve these problems, we propose a new model based on Deep Belief Nets to predict the CTR of mobile advertising, which combines together the powerful data representation and feature extraction capability of Deep Belief Nets, with the advantage of simplicity of traditional Logistic Regression models. Based on the training dataset with the information of over 40 million mobile advertisements during a period of 10 days, our experiments show that our new model has better estimation accuracy than the classic Logistic Regression (LR model by 5.57% and Support Vector Regression (SVR model by 5.80%.

  8. Sound Photographs to reveal vehicle pass-by sources with a calibrated source-strength level

    NARCIS (Netherlands)

    Mast, A.; Dool, T.C. van den; Toorn, J.D. van der; Watts, G.

    2003-01-01

    In national and European discussions, it appears that the conventional sound measurement techniques are insufficient to answer some relevant questions with respect to source strength of road vehicles. An example of such a question is: What is the importance of tyre-road noise on the one hand and

  9. Trans-Z-source Neutral Point Clamped inverter

    DEFF Research Database (Denmark)

    Mo, W.; Loh, P. C.; Li, D.

    2012-01-01

    Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...

  10. Separation of fission produced 106Ru from simulated high level nuclear wastes for production of brachytherapy sources

    International Nuclear Information System (INIS)

    Blicharska, Magdalena; Bartoś, Barbara; Krajewski, Seweryn; Bilewicz, Aleksander

    2014-01-01

    Brachytherapy is the common method for treating various tumors, and currently 106 Ru and 125 I applicators are the most frequently used. Considering that 106 Ru is a β emitter with maximum energy of 3.54 MeV, it is best indicated in the treatment of small melanomas, with up to 20 mm tissue range. 106 Ru is commercially obtained from neutron irradiated high enrichment 235 U target in process of production 99 Mo. At present, there are only a handful of ageing reactors worldwide capable of producing the 99 Mo, therefore alternative strategies for production of this key medical isotope are explored. In our work, we propose to use liquid high-level radioactive waste as a source of high activity of 106 Ru. Simple calculations indicate that 1 dm 3 of HLLW solution after 4 years of cooling contains about 500 GBq of 106 Ru. This amount of activity is enough for production of about few thousands of brachytherapy sources. Present communication reports results of our process development studies on the recovery of ruthenium radioisotopes from simulated solution of high level radioactive waste using oxidation-extraction method

  11. New hyperbranched polytriazoles containing isolation chromophore moieties derived from AB4 monomers through click chemistry under copper(I) catalysis: improved optical transparency and enhanced NLO effects.

    Science.gov (United States)

    Wu, Wenbo; Ye, Cheng; Yu, Gui; Liu, Yunqi; Qin, Jingui; Li, Zhen

    2012-04-02

    By modifying a synthetic procedure, two new hyperbranched polytriazoles (HP1 and HP2) containing isolation chromophores were synthesized successfully through click chemistry reactions under copper(I) catalysis. For the first time, these two polymers were derived from an AB(4)-type monomer, although they contain different end-capping chromophores. They are soluble in normal polar organic solvents and are well characterized. Thanks to the presence of the isolation chromophore, the two polymers demonstrate good nonlinear optical (NLO) properties and optical transparency, making them promising candidates for practical applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Level of Faecal Coliform Contamination of Drinking Water Sources ...

    African Journals Online (AJOL)

    2018-03-01

    Mar 1, 2018 ... ... of Drinking Water Sources and Its Associated Risk Factors in Rural Settings of North Gondar ... of Environmental & Occupational. Health & Safety, Gondar, Ethiopia. 2University of Gondar .... technicians. All sampling bottles ...

  13. Synthesis of Fluorinated Amphiphilic Block Copolymers Based on PEGMA, HEMA, and MMA via ATRP and CuAAC Click Chemistry

    Directory of Open Access Journals (Sweden)

    Fatime Eren Erol

    2014-01-01

    Full Text Available Synthesis of fluorinated amphiphilic block copolymers via atom transfer radical polymerization (ATRP and Cu(I catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC was demonstrated. First, a PEGMA and MMA based block copolymer carrying multiple side-chain acetylene moieties on the hydrophobic segment for postfunctionalization was carried out. This involves the synthesis of a series of P(HEMA-co-MMA random copolymers to be employed as macroinitiators in the controlled synthesis of P(HEMA-co-MMA-block-PPEGMA block copolymers by using ATRP, followed by a modification step on the hydroxyl side groups of HEMA via Steglich esterification to afford propargyl side-functional polymer, alkyne-P(HEMA-co-MMA-block-PPEGMA. Finally, click coupling between side-chain acetylene functionalities and 2,3,4,5,6-pentafluorobenzyl azide yielded fluorinated amphiphilic block copolymers. The obtained polymers were structurally characterized by 1H-NMR, 19F-NMR, FT-IR, and GPC. Their thermal characterizations were performed using DSC and TGA.

  14. Polycyclic aromatic hydrocarbons in urban air : concentration levels and patterns and source analysis in Nairobi, Kenya

    Energy Technology Data Exchange (ETDEWEB)

    Muthini, M.; Yoshimichi, H.; Yutaka, K.; Shigeki, M. [Yokohama National Univ., Yokohama (Japan). Graduate School of Environment and Information Sciences

    2005-07-01

    Polycyclic aromatic hydrocarbons (PAHs) present in the environment are often the result of incomplete combustion processes. This paper reported concentration levels and patterns of high molecular weight PAHs in Nairobi, Kenya. Daily air samples for 30 different PAHs were collected at residential, industrial and business sites within the city. Samples were then extracted using deuterated PAH with an automated Soxhlet device. Gas chromatography and mass spectrometry (GC-MS) with a capillary column was used to analyze the extracts using a selected ion monitoring (SIM) mode. Statistical analyses were then performed. PAH concentration levels were reported for average, median, standard deviation, range, and Pearson's correlation coefficients. Data were then analyzed for sources using a principal component analysis (PCA) technique and isomer ratio analysis. Nonparametric testing was then conducted to detect inherent differences in PAH concentration data obtained from the different sites. Results showed that pyrene was the most abundant PAH. Carcinogenic PAHs were higher in high-traffic areas. The correlation coefficient between coronene and benzo(ghi)pyrene was high. The PAH isomer ratio analysis demonstrated that PAHs in Nairobi are the product of traffic emissions and oil combustion. Results also showed that PAH profiles were not well separated. It was concluded that source distinction methods must be improved in order to better evaluate PAH emissions in the city. 9 refs., 2 tabs., 1 fig.

  15. In-vitro cytotoxic activities of poly(2-ethyl-2-oxazoline-based amphiphilic block copolymers prepared by CuAAC click chemistry

    Directory of Open Access Journals (Sweden)

    S. Gulyuz

    2018-02-01

    Full Text Available Synthesis and characterization of well-defined amphiphilic block copolymers containing poly(2-ethyl-2-oxazoline as hydrophilic block and poly(ε-caprolactone or poly(L-lactide as hydrophobic block is achieved by copper-catalyzed azide-alkyne cycloaddition (CuAAC click chemistry. The clickable precursors, α-alkyne-functionalized poly(ε-caprolactone and poly(L-lactide and ω-azido-functionalized poly(2-ethyl-2-oxazoline are simply prepared and joined using copper sulfate/ascorbic acid catalyst system at room temperature. The structures of precursors and amphiphilic block copolymers are characterized by spectroscopic, chromatographic and thermal analyses. The cytotoxic activities of resulting amphiphilic block copolymers and their precursors are investigated in the prostate epithelial and cancer cells under in-vitro conditions. The treatment of the healthy prostate epithelial cell line PNT1A reveals that no significant cytotoxicity, whereas some significant toxic effects on the prostate cancer cell lines are observed.

  16. Source SDK development essentials

    CERN Document Server

    Bernier, Brett

    2014-01-01

    The Source Authoring Tools are the pieces of software used to create custom content for games made with Valve's Source engine. Creating mods and maps for your games without any programming knowledge can be time consuming. These tools allow you to create your own maps and levels without the need for any coding knowledge. All the tools that you need to start creating your own levels are built-in and ready to go! This book will teach you how to use the Authoring Tools provided with Source games and will guide you in creating your first maps and mods (modifications) using Source. You will learn ho

  17. Sources of atmospheric aerosols controlling PM10 levels in Heraklion, Crete during winter time

    Science.gov (United States)

    Kalivitis, Nikolaos; Kouvarakis, Giorgos; Stavroulas, Iasonas; Kandilogiannaki, Maria; Vavadaki, Katerina; Mihalopoulos, Nikolaos

    2016-04-01

    High concentrations of Particulate Matter (PM) in the atmosphere have negative impact to human health. Thresholds for ambient concentrations that are defined by the directive 2008/50/EC are frequently exceeded even at background conditions in the Mediterranean region as shown in earlier studies. The sources of atmospheric particles in the urban environment of a medium size city of eastern Mediterranean are studied in the present work in order to better understand the causes and characteristics of exceedances of the daily mean PM10limit value of 50 μg m-3. Measurements were performed at the atmospheric quality measurement station of the Region of Crete, at the Heraklion city center on Crete island, during the winter/spring period of 2014-2015 and 2015-2016. Special emphasis was given to the study of the contribution of Black Carbon (BC) to the levels of PM10. Continuous measurements were performed using a beta-attenuation PM10monitor and a 7-wavelength Aethalometer with a time resolution of 30 and 5 minutes respectively. For direct comparison to background regional conditions, concurrent routine measurements at the atmospheric research station of University of Crete at Finokalia were used as background reference. Analysis of exceedances in the daily PM10 mass concentration showed that the total of the exceedances was related to long range transport of Saharan dust rather than local sources. However, compared to the Finokalia station it was found that there were 20% more exceedances in Heraklion, the addition of transported dust on the local pollution was the reason for the additional exceedance days. Excluding dust events, it was found that the PM10variability was dependent on the BC abundance, traffic during rush hours in the morning and biomass burning for domestic heating in the evening contributed significantly to PM10levels in Heraklion.

  18. Low-level radioactive waste source term model development and testing: Topical report

    International Nuclear Information System (INIS)

    Sullivan, T.M.; Kempf, C.R.; Suen, C.J.; Mughabghab, S.M.

    1988-08-01

    The Low-Level Waste Source Term Evaluation Project has the objective to develop a system model capable of predicting radionuclide release rates from a shallow land burial facility. The previous topical report for this project discussed the framework and methodology for developing a system model and divided the problem into four compartments: water flow, container degradation, waste form leaching, and radionuclide transport. Each of these compartments is described by submodels which will be coupled into the system model. From February 1987 to March 1988, computer models have been selected to predict water flow (FEMWATER) and radionuclide transport (FEMWASTE) and separate models have been developed to predict pitting corrosion of steel containers and leaching from porous waste forms contained in corrodible containers. This report discusses each of the models in detail and presents results obtained from applying the models to shallow land burial trenches over a range of expected conditions. 68 refs., 34 figs., 14 tabs

  19. Synthesis, characterization and thermal degradation of cross-linked polystyrene using the alkyne-functionalized esters as a cross-linker agent by click chemistry method

    Directory of Open Access Journals (Sweden)

    Hakan Akat

    2015-08-01

    Full Text Available AbstractIn this study, it has been demonstrated that cross-linked polystyrene (CPS was successfully prepared by using click chemistry. For this purpose, firstly, poly (styrene-co-4 chloromethylstyrene with 4-chloromethylstyrene was synthesized. Secondly, alkyne-functionalized esters (dipropargyl adipate, dipropargyl succinate were obtained using propargyl alcohol, adipoyl chloride and succinyl chloride. Azide-functionalized polystrene (PS-N3 and dipropargyl adipate (or dipropargyl succinate were reacted in N,N-dimethylformamide for 24 h at room temperature to give CPS. The synthesized polymer and compounds were characterized by nuclear magnetic resonance (1H-NMR, gel permeation chromatography (GPC, fourier transform infrared spectroscopy (FT-IR and thermogravimetric (TG/DTG analysis.. The surface properties were investigated by Scanning Electron Micrography (SEM.

  20. THE DIGESTIBILITY OF NUTRIENTS AT DIFFERENT LEVELS AND SOURCES OF LIPIDS IN DUCK DIETS

    Directory of Open Access Journals (Sweden)

    M.Yu. Sychov

    2016-04-01

    Full Text Available The estimation of digestibility of nutrients in ducklings was performed by use of feed contained the lipids from different levels and sources. Experimental studies were conducted in terms of problem research laboratory of feed additives of National Agriculture University of Ukraine. The material for scientific experiments was the ducklings of cross STAR 53 H.Y. Experiment was carried out by group-analog method. We determined the optimal content of crude fat in fodder of young ducks at the first stage of experiment and the best source of lipids at second stage. We increased the crude fat in duckling feed by the introduction of sunflower oil at first stage. The amount of fat in the duck feed was 5% in control group and this were 3% and 7% in group II and III. The ducks from experimental groups received feed with sunflower oil at the second stage of experiment, the ducks of group II and III obtained feed from soya, rapeseed, and palm fat. Feeding the ducks was done per group twice per day – in morning and evening. It was registered that the feeding of 8-14 days ducks by food with crude fat of 7% plausible increased the digestibility of protein by 3.2%, of fat by 5.1%, and nitrogen-free extractives matters by 2.7%. At the same time the use of feed for 36-42 days ducks with crude fat of 7% allows to get the best results with the more higher level of protein and fat digestibility by 4.9% and 4.8% respectively. The use of feed with the addition of soybean oil for duck feeding have a positive effect towards increasing the level of digestibility of organic matter, protein, fat, and fiber in all the duck age groups. At the same time the use of feed containing palm oil reduces the digestibility of fat by 4,1-6,7%  compared to control group, that obtained feed with sunflower oil . We confirmed the prospect of further research in order to to establish the optimal ratio of saturated and unsaturated fatty acids in the diet of ducks and to determine their

  1. Enantioselective separation of dansyl-DL-amino acids and some racemates on "click" functionalized native α-cyclodextrin based sub-2 μm columns.

    Science.gov (United States)

    Ai, Feng; Wang, Yong; Chen, Hui; Yang, Yanhui; Tan, Timothy Thatt Yang; Ng, Siu-Choon

    2013-04-21

    The current work demonstrates that native α-cyclodextrin, anchored onto sub-2 μm silica particles via "click" reactions and packed into a 5 cm column, was found to be effective for the resolution of 11 pairs of dansyl-DL-amino acids (DAAs) using ultra-high performance liquid chromatography (UHPLC). All DAAs were completely or partially separated on the column and the resolution achieved for 7 pairs of DAAs was significantly greater than 1.5. It was found that the buffer type exerted a profound impact on the separation. The effects of analyte substituents adjacent to the chiral center of analytes as well as operation conditions with respect to the separation efficiency were discussed. Five racemic compounds with single or double rings also got resolved on this short α-CD column to some extent.

  2. Source Apportionment of Suspended Sediment Sources using 137Cs and 210Pbxs

    Science.gov (United States)

    Lamba, J.; Karthikeyan, K.; Thompson, A.

    2017-12-01

    A study was conducted in the Pleasant Valley Watershed (50 km 2) in South Central Wisconsin to better understand sediment transport processes using sediment fingerprinting technique. Previous studies conducted in this watershed showed that resuspension of fine sediment deposited on the stream bed is an important source of suspended sediment. To better understand the role of fine sediment deposited on the stream bed, fallout radionuclides,137Cs and 210Pbxs were used to determine relative contribution to suspended sediment from in-stream (stream bank and stream bed) and upland sediment sources. Suspended sediment samples were collected during the crop growing season. Potential sources of suspended sediment considered in this study included cropland, pasture and in-stream (stream bed and stream bank). Suspended sediment sources were determined at a subwatershed level. Results of this study showed that in-stream sediment sources are important sources of suspended sediment. Future research should be conducted to better understand the role of legacy sediment in watershed-level sediment transport processes.

  3. Spectrometer control subsystem with high level functionality for use at the National Synchrotron Light Source

    International Nuclear Information System (INIS)

    Alberi, J.L.; Stubblefield, F.W.

    1980-11-01

    We have developed a subsystem capable of controlling stepping motors in a wide variety of vuv and x-ray spectrometers to be used at the National Sychrotron Light Source. The subsystem is capable of controlling up to 15 motors with encoder readback and ramped acceleration/deceleration. Both absolute and incremental encoders may be used in any mixture. Function commands to the subsystem are communicated via ASCII characters over an asynchronous serial link in a well-defined protocol in decipherable English. Thus the unit can be controlled via write statements in a high-level language. Details of hardware implementation will be presented

  4. Sources, amounts, and characteristics of low-level radioactive solid wastes

    International Nuclear Information System (INIS)

    Kibbey, A.H.; Godbee, H.W.

    1979-01-01

    Low-level radioactive solid wastes (LLW) are generated in the nuclear fuel cycle, national defense programs, institutional (especially medical/biological) applications, and other research and development activities. The estimated total accumulation of defense LLW, approx. 50.8 x 10 6 ft 3 (approx. 1.4 x 10 6 m 3 ), is roughly three times that estimated for commercial LLW, mill tailings excepted. All nuclear fuel cycle steps generate some LLW, but power plants are the chief source. From 1975 through 1977, reactor process stream cleanup generated approx. 1 x 10 6 (approx. 2.8 x 10 4 m 3 ) annually. Spent fuel storage (or reprocessing) and facility decontamination and decommissioning will become important LLW generators as the nuclear power industry matures. The LLW contains dry contaminated trash, much of which is combustible and/or compactible; discarded tools and equipment; wet filter sludges and ion-exchange resins; disposable filter cartridges; and solidified or sorbed liquids, including some organics. A distinguishing characteristic of LLW is a long-lived alpha-emitting transuranic content of 5 ft 3 (approx. 2.1 x 10 4 m 3 )/y. The majority of these wastes, > 6 x 10 5 ft 3 (> 1.7 x 10 4 m 3 ), was medical and academic wastes which usually contained isotopes with induced activities of less than or equal to 60-day half-life, neglecting 3 H and 14 C

  5. Open Source GIS Connectors to the NASA GES DISC Satellite Data

    Science.gov (United States)

    Pham, L.; Kempler, S. J.; Yang, W.

    2014-12-01

    The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) houses a suite of satellite-derived GIS data including high spatiotemporal resolution precipitation, air quality, and modeled land surface parameter data. The data are extremely useful to various GIS research and applications at regional, continental, and global scales, as evidenced by the growing GIS user requests to the data. On the other hand, we also found that some GIS users, especially those from the ArcGIS community, having difficulties in obtaining, importing, and using our data, primarily due to the unfamiliarity of the users with our products and GIS software's lack of capabilities in dealing with the predominately raster form data in various sometimes very complicated formats. In this presentation, we introduce a set of open source ArcGIS data connectors that significantly simplify the access and use of our data in ArcGIS. With the connectors, users do not need to know the data access URLs, the access protocols or syntaxes, and data formats. Nor do they need to browse through a long list of variables that are often embedded into one single science data file and whose names may sometimes be confusing to those not familiar with the file (such as variable CH4_VMR_D for "CH4 Volume mixing ratio from the descending orbit" and variable EVPsfc for "Total Evapotranspiration"). The connectors will expose most GIS-related variables to the users with easy to understand names. User can simply define the spatiotemporal range of their study, select interested parameter(s), and have the needed data be downloaded, imported, and displayed in ArcGIS. The connectors are python text files and there is no installation process. They can be placed at any user directory and be started by simply clicking on it. In the presentation, we'll also demonstrate how to use the tools to load GES DISC time series air quality data with a few clicks and how such data depict the spatial and temporal patterns of

  6. Indoor and Outdoor Levels and Sources of Submicron Particles (PM1) at Homes in Edmonton, Canada.

    Science.gov (United States)

    Bari, Md Aynul; Kindzierski, Warren B; Wallace, Lance A; Wheeler, Amanda J; MacNeill, Morgan; Héroux, Marie-Ève

    2015-06-02

    Exposure to submicron particles (PM1) is of interest due to their possible chronic and acute health effects. Seven consecutive 24-h PM1 samples were collected during winter and summer 2010 in a total of 74 nonsmoking homes in Edmonton, Canada. Median winter concentrations of PM1 were 2.2 μg/m(3) (interquartile range, IQR = 0.8-6.1 μg/m(3)) and 3.3 μg/m(3) (IQR = 1.5-6.9 μg/m(3)) for indoors and outdoors, respectively. In the summer, indoor (median 4.4 μg/m(3), IQR = 2.4-8.6 μg/m(3)) and outdoor (median 4.3 μg/m(3), IQR = 2.6-7.4 μg/m(3)) levels were similar. Positive matrix factorization (PMF) was applied to identify and apportion indoor and outdoor sources of elements in PM1 mass. Nine sources contributing to both indoor and outdoor PM1 concentrations were identified including secondary sulfate, soil, biomass smoke and environmental tobacco smoke (ETS), traffic, settled and mixed dust, coal combustion, road salt/road dust, and urban mixture. Three additional indoor sources were identified i.e., carpet dust, copper-rich, and silver-rich. Secondary sulfate, soil, biomass smoke and ETS contributed more than 70% (indoors: 0.29 μg/m(3), outdoors: 0.39 μg/m(3)) of measured elemental mass in PM1. These findings can aid understanding of relationships between submicron particles and health outcomes for indoor/outdoor sources.

  7. Effect of dietary calcium level and source on mineral utilisation by piglets fed diets containing exogenous phytase.

    Science.gov (United States)

    Schlegel, P; Gutzwiller, A

    2017-10-01

    Calcium and phosphorus are essential minerals, closely linked in digestive processes and metabolism. With widespread use of low P diets containing exogenous phytase, the optimal dietary Ca level was verified. The 40-day study evaluated the effects of Ca level (4, 7 and 10 g/kg diet) and Ca source (Ca from CaCO 3 and from Lithothamnium calcareum) on mineral utilisation in 72 piglets (7.9 ± 1.0 kg BW) fed an exogenous phytase containing diet with 2.9 g digestible P/kg. Measured parameters were growth performance, stomach mineral solubility, bone breaking strength and urinary, serum and bone mineral concentration. The apparent total tract digestibility of minerals was also assessed in the two diets with 7 g Ca/kg, using 12 additional pigs. Regardless of Ca source, increasing dietary Ca impaired feed conversion ratio, increased urinary pH, increased serum and urinary Ca, decreased serum and urinary P, decreased serum Mg and increased urinary Mg, increased serum AP activity, decreased bone Mg increased bone Zn. Bone breaking strength was improved with 7 compared to 4 g Ca/kg. Compared to CaCO 3 , Ca from Lithothamnium calcareum increased serum Mg and with, 10 g Ca/kg, it limited body weight gain. The dose response of Ca in a diet with 2.9 g digestible P/kg and including exogenous phytase indicated that: (i) a low dietary Ca was beneficial for piglet growth, but was limiting the metabolic use of P; (ii) a high dietary Ca level impaired P utilisation; (iii) the optimal P utilisation and bone breaking strength was obtained with a dietary Ca-to-digestible P ratio of 2.1 to 2.4:1; (iv). Increasing dietary Ca reduced Mg utilisation, but not Zn status, when fed at adequate level. Finally, Ca from Lithothamnium calcareum had similar effects on Ca and P metabolism as CaCO 3 , but impaired growth when fed at the highest inclusion level. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  8. Single source sound production and dynamic beam formation in echolocating harbour porpoises (Phocoena phocoena)

    DEFF Research Database (Denmark)

    Madsen, Peter Teglberg; Wisniewska, Danuta Maria; Beedholm, Kristian

    2010-01-01

    of three echolocating porpoises (Phocoena phocoena) with symmetrical pairs of phonic lips. Using time of arrival differences on three hydrophones, we show that all recorded clicks from these three porpoises are produced by the right pair of phonic lips with no evidence of simultaneous or independent...

  9. Vocalization Source Level Distributions and Pulse Compression Gains of Diverse Baleen Whale Species in the Gulf of Maine

    Directory of Open Access Journals (Sweden)

    Delin Wang

    2016-10-01

    Full Text Available The vocalization source level distributions and pulse compression gains are estimated for four distinct baleen whale species in the Gulf of Maine: fin, sei, minke and an unidentified baleen whale species. The vocalizations were received on a large-aperture densely-sampled coherent hydrophone array system useful for monitoring marine mammals over instantaneous wide areas via the passive ocean acoustic waveguide remote sensing technique. For each baleen whale species, between 125 and over 1400 measured vocalizations with significantly high Signal-to-Noise Ratios (SNR > 10 dB after coherent beamforming and localized with high accuracies (<10% localization errors over ranges spanning roughly 1 km–30 km are included in the analysis. The whale vocalization received pressure levels are corrected for broadband transmission losses modeled using a calibrated parabolic equation-based acoustic propagation model for a random range-dependent ocean waveguide. The whale vocalization source level distributions are characterized by the following means and standard deviations, in units of dB re 1 μ Pa at 1 m: 181.9 ± 5.2 for fin whale 20-Hz pulses, 173.5 ± 3.2 for sei whale downsweep chirps, 177.7 ± 5.4 for minke whale pulse trains and 169.6 ± 3.5 for the unidentified baleen whale species downsweep calls. The broadband vocalization equivalent pulse-compression gains are found to be 2.5 ± 1.1 for fin whale 20-Hz pulses, 24 ± 10 for the unidentified baleen whale species downsweep calls and 69 ± 23 for sei whale downsweep chirps. These pulse compression gains are found to be roughly proportional to the inter-pulse intervals of the vocalizations, which are 11 ± 5 s for fin whale 20-Hz pulses, 29 ± 18 for the unidentified baleen whale species downsweep calls and 52 ± 33 for sei whale downsweep chirps. The source level distributions and pulse compression gains are essential for determining signal-to-noise ratios and hence detection regions for baleen whale

  10. Effects of dietary nitrogen levels and carbohydrate sources on apparent ruminal synthesis of some B vitamins in dairy cows.

    Science.gov (United States)

    Beaudet, V; Gervais, R; Graulet, B; Nozière, P; Doreau, M; Fanchone, A; Castagnino, D D S; Girard, C L

    2016-04-01

    Effects of nitrogen level and carbohydrate source on apparent ruminal synthesis (ARS) of thiamin, riboflavin, niacin, vitamin B6, folates, and vitamin B12 were evaluated using 4 lactating Holstein cows distributed in a 4 × 4 Latin square design with treatments following a 2 × 2 factorial arrangement. Cows were fitted with cannulas in the rumen and proximal duodenum. The treatments were 2 N levels and 2 carbohydrate sources. The diet with the high N level provided 14% crude protein, calculated to meet 110% of the protein requirements and an adequate supply in rumen-degradable protein, whereas the diet with the low N level contained 11% crude protein, calculated to meet 80% of the protein requirements with a shortage in rumen-degradable protein. Carbohydrate source treatments differed by their nature (i.e., high in starch from barley, corn, and wheat, or high in fiber from soybean hulls and dehydrated beet pulp). All 4 diets were isoenergetic, based on corn silage, and had the same forage-to-concentrate ratio (60:40, dry matter basis). Duodenal flow was determined using YbCl3 as a marker. Each B-vitamin ARS was calculated as duodenal flow minus daily intake. The intake of several B vitamins varied among treatments, but because the animals consumed a similar amount of feed every day (average of 20 kg of dry matter/d) the difference was mostly due to vitamin content of each ingredient and their relative proportion in the diets. Decreasing N concentration in the diet reduced vitamin B6 duodenal flow and increased its apparent ruminal degradation. It also decreased duodenal flow and ARS of folates. The high-starch diets increased duodenal flow and ruminal balance of riboflavin, vitamin B6, and folates, whereas the high-fiber diets increased vitamin B12 ARS and duodenal flow. These effects on apparent synthesis are possibly due to changes in ruminal fermentation. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  11. A multi-criteria methodology for energy planning and developing renewable energy sources at a regional level: A case study Thassos, Greece

    International Nuclear Information System (INIS)

    Mourmouris, J.C.; Potolias, C.

    2013-01-01

    Rational energy planning under the pressure of environmental and economic problems is imperative to humanity. An evaluational framework is proposed in order to support energy planning for promoting the use of renewable energy sources. A multi-criteria decision analysis is adopted, detailing exploitation of renewable energy sources (including Wind, Solar, Biomass, Geothermal, and small Hydro) for power and heat generation. The aim of this paper is the analysis and development of a multilevel decision-making structure, utilizing multiple criteria for energy planning and exploitation of Renewable Energy Sources of at the regional level. The proposed evaluation framework focuses on the use of a multi-criteria approach as a tool for supporting energy planning in the area of concern, based on a pool of qualitative and quantitative evaluation criteria. The final aim of this study is to discover the optimal amount of each Renewable Energy Source that can be produced in the region and to contribute to an optimal energy mix. In this paper, a case study for the island of Thassos, Greece is analyzed. The results prove that Renewable Energy Sources exploitation at a regional level can satisfy increasing power demands through environmental-friendly energy systems that combine wind power, biomass and PV systems. - Highlights: ► An evaluational framework is proposed in order to support energy planning. ► A multi-criteria decision analysis is adopted, detailing exploitation of RES for power and heat generation. ► The aim is to discover the optimal amount of each RES that can be produced in each region.

  12. Evaluating public ambulance service levels by applying a GIS based ...

    African Journals Online (AJOL)

    If you would like more information about how to print, save, and work with PDFs, Highwire Press provides a helpful Frequently Asked Questions about PDFs. Alternatively, you can download the PDF file directly to your computer, from where it can be opened using a PDF reader. To download the PDF, click the Download link ...

  13. A sensitive fluorescent sensor for quantification of alpha-fetoprotein based on immunosorbent assay and click chemistry.

    Science.gov (United States)

    Xie, Qunfang; Weng, Xiuhua; Lu, Lijun; Lin, Zhenyu; Xu, Xiongwei; Fu, Caili

    2016-03-15

    A novel fluoresencent immunosensor for determination of cancer biomarkers such as alpha-fetoprotein (AFP) was designed by utilizing both the high specificity of antigen-antibody sandwich structure and the high sensitivity of the click chemistry based fluorescence detection. Instead of an enzyme or fluorophore, the CuO nanoparticles are labeled on the detection antibody, which was not susceptible to the change of the external environments. The CuO nanoparticles which were modified on the sandwich structure can be dissolved to produce Cu(2+) ions with the help of HCl and then the Cu(2+) ions were reduced by sodium ascorbate to produce Cu(+) ions which triggered the Cu(+) catalyzed alkyne-azide cycloaddition (CuAAC) reaction between the weak fluorescent compound (3-azido-7-hydroxycoumarin) and propargyl alcohol to form a strong fluorescent compound. A good linear relationship was observed between the fluorescence increase factor of the system and the concentration of AFP in the range of 0.025-5.0 ng/mL with a detection limit of 12 pg/mL (S/N=3). The proposed fluorescent sensor had been applied to detect AFP in the human serum samples and gave satisfactory results. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Click Chemistry-based Discovery of [3-Hydroxy-5-(1H-1,2,3-triazol-4-yl)picolinoyl]glycines as Orally Active Hypoxia Inducing Factor Prolyl Hydroxylase Inhibitors with Favorable Safety Profiles for the Treatment of Anemia.

    Science.gov (United States)

    Wu, Yue; Jiang, Zhensheng; Li, Zhihong; Gu, Jing; You, Qi-Dong; Zhang, Xiaojin

    2018-06-01

    As a gene associated with anemia, the erythropoiesis gene is physiologically expressed under hypoxia regulated by hypoxia-inducing factor-α (HIF-α). Thus, stabilizing HIF-α is a potent strategy to stimulate the expression and secretion of erythropoiesis. In this study we applied click chemistry to the discovery of HIF prolyl hydroxylase 2 (HIF-PHD2) inhibitors for the first time and a series of triazole compounds showed preferable inhibitory activity in fluorescence polarization assay. Of particular note was the orally active HIF-PHD inhibitor 15i (IC50 = 62.23 nM), which was almost ten times more active than the phase III drug FG-4592 (IC50 = 591.4 nM). Furthermore, it can upregulate the hemoglobin of cisplatin induced anemia mice (120 g/L) to normal levels (160 g/L) with no apparent toxicity observed in vivo. These results confirm that triazole compound 15i is a promising candidate for the treatment of renal anemia.

  15. How exogenous nitric oxide regulates nitrogen assimilation in wheat seedlings under different nitrogen sources and levels.

    Science.gov (United States)

    Balotf, Sadegh; Islam, Shahidul; Kavoosi, Gholamreza; Kholdebarin, Bahman; Juhasz, Angela; Ma, Wujun

    2018-01-01

    Nitrogen (N) is one of the most important nutrients for plants and nitric oxide (NO) as a signaling plant growth regulator involved in nitrogen assimilation. Understanding the influence of exogenous NO on nitrogen metabolism at the gene expression and enzyme activity levels under different sources of nitrogen is vitally important for increasing nitrogen use efficiency (NUE). This study investigated the expression of key genes and enzymes in relation to nitrogen assimilation in two Australian wheat cultivars, a popular high NUE cv. Spitfire and a normal NUE cv. Westonia, under different combinations of nitrogen and sodium nitroprusside (SNP) as the NO donor. Application of NO increased the gene expressions and activities of nitrogen assimilation pathway enzymes in both cultivars at low levels of nitrogen. At high nitrogen supplies, the expressions and activities of N assimilation genes increased in response to exogenous NO only in cv. Spitfire but not in cv. Westonia. Exogenous NO caused an increase in leaf NO content at low N supplies in both cultivars, while under high nitrogen treatments, cv. Spitfire showed an increase under ammonium nitrate (NH4NO3) treatment but cv. Westonia was not affected. N assimilation gene expression and enzyme activity showed a clear relationship between exogenous NO, N concentration and N forms in primary plant nitrogen assimilation. Results reveal the possible role of NO and different nitrogen sources on nitrogen assimilation in Triticum aestivum plants.

  16. Levels of bioactive lipids in cooking oils: olive oil is the richest source of oleoyl serine.

    Science.gov (United States)

    Bradshaw, Heather B; Leishman, Emma

    2016-05-01

    Rates of osteoporosis are significantly lower in regions of the world where olive oil consumption is a dietary cornerstone. Olive oil may represent a source of oleoyl serine (OS), which showed efficacy in animal models of osteoporosis. Here, we tested the hypothesis that OS as well as structurally analogous N-acyl amide and 2-acyl glycerol lipids are present in the following cooking oils: olive, walnut, canola, high heat canola, peanut, safflower, sesame, toasted sesame, grape seed, and smart balance omega. Methanolic lipid extracts from each of the cooking oils were partially purified on C-18 solid-phase extraction columns. Extracts were analyzed with high-performance liquid chromatography-tandem mass spectrometry, and 33 lipids were measured in each sample, including OS and bioactive analogs. Of the oils screened here, walnut oil had the highest number of lipids detected (22/33). Olive oil had the second highest number of lipids detected (20/33), whereas grape-seed and high-heat canola oil were tied for lowest number of detected lipids (6/33). OS was detected in 8 of the 10 oils tested and the levels were highest in olive oil, suggesting that there is something about the olive plant that enriches this lipid. Cooking oils contain varying levels of bioactive lipids from the N-acyl amide and 2-acyl glycerol families. Olive oil is a dietary source of OS, which may contribute to lowered prevalence of osteoporosis in countries with high consumption of this oil.

  17. CLICK CHEMISTRY AS AN EFFICIENT TOOL TO ACCESS 6-AMINO-5-CYANO-2(1H)-PYRIMIDINONE DIMERS Klick-Chemie als effizientes Werkzeug ZUGREIFEN 6-Amino-5-cyano-2 (1H)-pyrimidinon Dimeren

    OpenAIRE

    Ennaji Najahi, Jan Sudor ,Françoise Nepveu, Fethi Zribi, Romain Duval and Fakher Chabchoub

    2011-01-01

    We describe here the synthesis of triazole-linked 6-amino-5-cyano-2(1H)-pyrimidinone dimers using 1,3-dipolar cycloaddition. The azido-precursor was prepared through the reaction of ethyl 2,2-dicyanovinylcarbamate derivatives with p-azidoaniline. The second precursor, a 6-amino-5- cyano-1-(3 or 4-ethynylphenyl)-4-substituted-2(1H)-pyrimidinone, was obtained from ethyl 2,2- dicyanovinylcarbamate derivatives reacting with 3-ethynylaniline or 4-ethynylaniline. Consequently, the two ‘click system...

  18. Miniature neutron sources: Thermal neutron sources and their users in the academic field

    International Nuclear Information System (INIS)

    Egelstaff, P.A.

    1992-01-01

    The three levels of thermal neutron sources are introduced - University laboratory sources infrastructure sources and world-class sources - and the needs for each kind and their inter-dependence will be emphasized. A description of the possibilities for University sources based on α-Be reactions or spontaneous fission emission is given, and current experience with them is described. A new generation of infrastructure sources is needed to continue the regional programs based on small reactors. Some possibilities for accelerator sources that could meet this need are considered

  19. Nitrite reductase expression is regulated at the post-transcriptional level by the nitrogen source in Nicotiana plumbaginifolia and Arabidopsis thaliana.

    Science.gov (United States)

    Crété, P; Caboche, M; Meyer, C

    1997-04-01

    Higher plant nitrite reductase (NiR) is a monomeric chloroplastic protein catalysing the reduction of nitrite, the product of nitrate reduction, to ammonium. The expression of this enzyme is controlled at the transcriptional level by light and by the nitrogen source. In order to study the post-transcriptional regulation of NiR, Nicotiana plumbaginifolia and Arabidopsis thaliana were transformed with a chimaeric NiR construct containing the tobacco leaf NiR1 coding sequence driven by the CaMV 35S RNA promoter. Transformed plants did not show any phenotypic difference when compared with the wild-type, although they overexpressed NiR activity in the leaves. When these plants were grown in vitro on media containing either nitrate or ammonium as sole nitrogen source, NiR mRNA derived from transgene expression was constitutively expressed, whereas NiR activity and protein level were strongly reduced on ammonium-containing medium. These results suggest that, together with transcriptional control, post-transcriptional regulation by the nitrogen source is operating on NiR expression. This post-transcriptional regulation of tobacco leaf NiR1 expression was observed not only in the closely related species N. plumbaginifolia but also in the more distant species A. thaliana.

  20. Polychlorinated Biphenyl Sources, Emissions, and Environmental Levels in school Buildings (PCB Workshop presentation)

    Science.gov (United States)

    Measure PCB emission rates from primary sources in laboratory chambersMeasure transport and sorption by materials and dust in laboratory chambersCharacterize PCBs in school building materialsEstimate PCB emission rates from sources in schoolsExamine congener patterns in sources a...