Sample records for click source levels

  1. Sperm whale clicks: Directionality and source level revisited

    DEFF Research Database (Denmark)

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


    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....... 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....... This implicates sonar as a possible function of the clicks. Thus, previously published properties of sperm whale clicks underestimate the capabilities of the sound generator and therefore cannot falsify the Norris and Harvey theory....

  2. 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.

  3. A `Clicked' Tetrameric Hydroxamic Acid Glycopeptidomimetic Antagonizes Sugar-Lectin Interactions On The Cellular Level (United States)

    Zhang, Hai-Lin; Zang, Yi; Xie, Juan; Li, Jia; Chen, Guo-Rong; He, Xiao-Peng; Tian, He


    A tetrameric N-acetyl galactosaminyl (GalNAc) peptidomimetic was constructed by N-acetylation of repeating proline-based hydroxamic acid units, followed by a convergent `click chemistry' coupling. This novel glycopeptidomimetic was determined to effectively antagonize the interaction between a transmembrane hepatic lectin and GalNAc on the cellular level.

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

    DEFF Research Database (Denmark)

    Madsen, Peter Teglberg; Wahlberg, Magnus


    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. [Auditory-evoked responses to a monaural or a binaural click, recorded from the vertex, as in two temporal derivations; effect of interaural time differences (author's transl)]. (United States)

    Botte, M C; Chocholle, R


    The auditory-evoked responses have been recorded on 5 subject by vertex, right temporal and left temporal electrodes simultaneously. 30 dB sensation level clicks were used as stimuli; one click was presented only to the right ear, or one click only to the left ear, or one click to the right ear and another click to the left ear with a variable interaural time difference in this latter case (0-150 ms). The N-P amplitude variations and the N and P latency variations have been studied and compared to those observed in the perceived lateralizations of the sound source.

  6. Click bait

    DEFF Research Database (Denmark)

    Blom, Jonas Nygaard; Reinecke Hansen, Kenneth


    This is why you should read this article. Although such an opening statement does not make much sense read in isolation, journalists often write headlines like this on news websites. They use the forward-referring technique as a stylistic and narrative luring device trying to induce anticipation...... 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...... to lead to a recurrent use of forward-reference in Danish online news headlines. In addition, the article contributes to reference theory by expanding previous models on phoricity to include multimodal references on the web....

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

    DEFF Research Database (Denmark)

    Eskesen, Ida; Wahlberg, Magnus; Simon, Malene


    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...

  8. Nanoplasmonics tuned ``click chemistry'' (United States)

    Tijunelyte, I.; Guenin, E.; Lidgi-Guigui, N.; Colas, F.; Ibrahim, J.; Toury, T.; Lamy de La Chapelle, M.


    Nanoplasmonics is a growing field of optical condensed matter science dedicated to optical phenomena at the nanoscale level in metal systems. Extensive research on noble metallic nanoparticles (NPs) has emerged within the last two decades due to their ability to keep the optical energy concentrated in the vicinity of NPs, in particular, the ability to create optical near-field enhancement followed by heat generation. We have exploited these properties in order to induce a localised ``click'' reaction in the vicinity of gold nanostructures under unfavourable experimental conditions. We demonstrate that this reaction can be controlled by the plasmonic properties of the nanostructures and we propose two physical mechanisms to interpret the observed plasmonic tuning of the ``click'' chemistry.Nanoplasmonics is a growing field of optical condensed matter science dedicated to optical phenomena at the nanoscale level in metal systems. Extensive research on noble metallic nanoparticles (NPs) has emerged within the last two decades due to their ability to keep the optical energy concentrated in the vicinity of NPs, in particular, the ability to create optical near-field enhancement followed by heat generation. We have exploited these properties in order to induce a localised ``click'' reaction in the vicinity of gold nanostructures under unfavourable experimental conditions. We demonstrate that this reaction can be controlled by the plasmonic properties of the nanostructures and we propose two physical mechanisms to interpret the observed plasmonic tuning of the ``click'' chemistry. Electronic supplementary information (ESI) available: NMR study on reaction initiation, SERS spectra and temperature calculations. See DOI: 10.1039/c5nr09018k

  9. 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...

  10. Rarely clicking Muller's ratchets (United States)

    Eule, Stephan; Metzger, Jakob


    In populations of finite size, weakly deleterious mutations can fix by chance. This phenomenon has been termed Muller's ratchet and one click of the ratchet refers to the loss of the fittest class of individuals with the fewest mutations. Despite the simplicity of the classical mathematical model of Muller's ratchet, surprisingly little is known in the biologically relevant regime where a click of the ratchet is a rare event. Here we show numerically that in this regime the rate of the ratchet strongly depends on the applied microscopic formulation (Wiright-Fisher/Moran) of the model, thus challenging the widely used diffusion approximation. Furthermore by employing a WKB-approximation in a simplified model, we obtain analytical results for the click rate, which agree well with the click rate of the full ratchet of the corresponding microscopical model.

  11. Click chemistry with DNA


    El-Sagheer, Afaf H.; Brown, Tom


    The advent of click chemistry has led to an influx of new ideas in the nucleic acids field. The copper catalysed alkyne–azide cycloaddition (CuAAC) reaction is the method of choice for DNA click chemistry due to its remarkable efficiency. It has been used to label oligonucleotides with fluorescent dyes, sugars, peptides and other reporter groups, to cyclise DNA, to synthesise DNA catenanes, to join oligonucleotides to PNA, and to produce analogues of DNA with modified nucleobases and backbone...

  12. Single-Source Oriented Application Level Multicast

    Institute of Scientific and Technical Information of China (English)

    PI Ren-jie; SONG Jun-de


    Using application level multicast can partly pad the lack of IP multicast deployment. To perform single-source applications in hierarchical topology, we propose an application level multicast approach, Hierarchical Topology Aware Grouping (HTAG), which exploits information about path overlap among members and topological hierarchy to construct overlay tree at different network layers. We present simulations of both our protocol and the TAG over generated hierarchical topologies. The results indicate the effectiveness of our approach in reducing duplicate packets and preserving available bandwidth, with reasonable delays increase.

  13. Fighting Online Click-Fraud Using Bluff Ads

    CERN Document Server

    Haddadi, Hamed


    Online advertising is currently the greatest source of revenue for many Internet giants. The increased number of specialized websites and modern profiling techniques, have all contributed to an explosion of the income of ad brokers from online advertising. The single biggest threat to this growth, is however, click-fraud. Trained botnets and even individuals are hired by click-fraud specialists in order to maximize the revenue of certain users from the ads they publish on their websites, or to launch an attack between competing businesses. In this note we wish to raise the awareness of the networking research community on potential research areas within this emerging field. As an example strategy, we present Bluff ads; a class of ads that join forces in order to increase the effort level for click-fraud spammers. Bluff ads are either targeted ads, with irrelevant display text, or highly relevant display text, with irrelevant targeting information. They act as a litmus test for the legitimacy of the individual...

  14. Clicks, Bricks and Spondulicks (United States)

    Fisher, Kenn


    "Clicks, Bricks and Spondulicks" is the title of a seminar organised by PEB to examine the relationship between the built learning environment and information and communications technology (ICT), as well as cost implications. The meeting sought to determine whether educational buildings and ICT should continue to be seen as separate…

  15. Think Before You Click

    CERN Multimedia


    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...

  16. 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;


    An increasing number of smaller odontocetes have recently been shown to produce stereotyped narrow-band high-frequency (NBHF) echolocation clicks. Click source parameters of NBHF clicks are very similar, and it is unclear whether the sonars of individual NBHF species are adapted to specific...

  17. Copper Nanoparticles in Click Chemistry. (United States)

    Alonso, Francisco; Moglie, Yanina; Radivoy, Gabriel


    effective in the multicomponent and regioselective synthesis of 1,4-disubstituted 1,2,3-triazoles in water from organic halides as azido precursors; magnetically recoverable CuNPs (3.0 ± 0.8 nm) supported on MagSilica could be alternatively used for the same purpose under similar conditions. Incorporation of an aromatic substituent at the 1-position of the triazole could be accomplished using the same CuNPs/C catalytic system starting from aryldiazonium salts or anilines as azido precursors. CuNPs/C in water also catalyzed the regioselective double-click synthesis of β-hydroxy-1,2,3-triazoles from epoxides. Furthermore, alkenes could be also used as azido precursors through a one-pot CuNPs/C-catalyzed azidosulfenylation-CuAAC sequential protocol, providing β-methylsulfanyl-1,2,3-triazoles in a stereo- and regioselective manner. In all types of reaction studied, CuNPs/C exhibited better behavior than some commercial copper catalysts with regard to the metal loading, reaction time, yield, and recyclability. Therefore, the results of this study also highlight the utility of nanosized copper in click chemistry compared with bulk copper sources.

  18. Echolocation clicks of free-ranging Cuvier's beaked whales (Ziphius cavirostris) (United States)

    Zimmer, Walter M. X.; Johnson, Mark P.; Madsen, Peter T.; Tyack, Peter L.


    Strandings of beaked whales of the genera Ziphius and Mesoplodon have been reported to occur in conjunction with naval sonar use. Detection of the sounds from these elusive whales could reduce the risk of exposure, but descriptions of their vocalizations are at best incomplete. This paper reports quantitative characteristics of clicks from deep-diving Cuvier's beaked whales (Ziphius cavirostris) using a unique data set. Two whales in the Ligurian Sea were simultaneously tagged with sound and orientation recording tags, and the dive tracks were reconstructed allowing for derivation of the range and relative aspect between the clicking whales. At depth, the whales produced trains of regular echolocation clicks with mean interclick intervals of 0.43 s (+/-0.09) and 0.40 s (+/-0.07). The clicks are frequency modulated pulses with durations of ~200 μs and center frequencies around 42 kHz, -10 dB bandwidths of 22 kHz, and Q3 dB of 4. The sound beam is narrow with an estimated directionality index of more than 25 dB, source levels up to 214 dBpp re: 1 μPa at 1 m, and energy flux density of 164 dB re: 1 μPa2 s. As the spectral and temporal properties are different from those of nonziphiid odontocetes the potential for passive detection is enhanced. .

  19. Synthesis: Click chemistry gets reversible (United States)

    Fulton, David A.


    'Click' chemistry allows for the linking together of chemical modules, however, there are currently no methods that also allow for facile 'declicking' to unlink them. Now, a method has been developed to click together amines and thiols, and then allow a chemically triggered declick reaction to release the original molecular components.

  20. 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.

  1. Clicking in shallow rivers: short-range echolocation of Irrawaddy and Ganges River dolphins in a shallow, acoustically complex habitat. (United States)

    Jensen, Frants H; Rocco, Alice; Mansur, Rubaiyat M; Smith, Brian D; Janik, Vincent M; Madsen, Peter T


    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.

  2. 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

    recorded seahorse clicks, points towards a multimodal statistical distribution, which is the existence of more than one fitting component for the majority of seahorse click signals above the tank ambient noise level. This fact has been appraised towards...

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

    DEFF Research Database (Denmark)

    Kohler, Wilhelm; Smolka, Marcel


    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....

  4. Click Chemistry的翻译%Translation of Click Chemistry

    Institute of Scientific and Technical Information of China (English)



    诺贝尔奖得主Sharpless等于2001年首次提出click chemistry一词,之后这一概念广泛应用于高效合成有机小分子化合物和各种结构的高分子,国内的学者也在积极开展关于click chemistry的研究。赵卫光等发表了一篇综述,简要介绍了click chemistry在有机小分子合成中的一些应用。

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  6. 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


    (Lagenorhynchus cruciger) and Hector's dolphins (Cephalorhynchus hectori ) were made in the Drake Passage between Tierra del Fuego and the Antarctic Peninsular and Banks Peninsular Akaroa Harbour, New Zealand with a four element hydrophone array. Analysis of source parameters shows that both species produce...

  7. The Click and Twitch in Contemporary Poetry. (United States)

    Meredith, Bernard

    It is the creative writing instructor's role to help the student turn "twitch" poems into "click" poems ("twitch" being a kind of verbal hypertension that takes shape in the absence of anything humanly important to say on the poet's part and "click" being the finished poem that makes a sound like the click of the lid on a perfectly made box).…

  8. Z - Source Multi Level Inverter Based PV Generation System

    Directory of Open Access Journals (Sweden)

    T. Lakhmi kanth


    Full Text Available In this paper a novel technique of Z-Source multilevel Inverter based PV Generation system is implemented and simulated using MATLAB-Simulink simulation software. The Photovoltaic cells are healthier option for converting solar energy into electricity. Due to high capital cost and low efficiency PV cells have not yet been a fully smart choice for electricity users. To enhance the performance of the system, Z-Source multi level inverter can be used in place of conventional Voltage Source Inverter (VSI in Solar Power Generation System. The PV cell model is developed using circuit mathematical equations. The Z-Source multilevel inverter is modeled to realize boosted DC to AC conversion (inversion with low THD. Outcome shows that the energy conversion efficiency of ZSMLI is a lot improved as compared to conventional voltage Source Inverter (VSI. By doing FFT analysis we can know the total THD.

  9. Underwater Source-Level Estimation using Sparsity-Cognizant Source-Location Mapping (United States)


    shallow water is characterized by multipath due to the multiple interactions that they sustain with the sea surface and sea floor , by refraction due to a...TECHNICAL REPORT 2060 ember 2014 Underwater Source-Level Estimation using Sparsity-Cognizant Source-Location Mapping localize the target, which is accomplished by using the Sparsity-Cognizant Source Location Mapping (scSLM) algorithm, developed at the Space and

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

    NARCIS (Netherlands)

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


    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 proces

  11. Get the right mix of bricks & clicks. (United States)

    Gulati, R; Garino, J


    The bright line that once distinguished the dot-com from the incumbent is rapidly fading. Success in the new economy will go to those who can execute clicks-and-mortar strategies that bridge the physical and virtual worlds. But how executives forge such strategies is under considerable debate. Despite the obvious benefits that integration offers--cross-promotion, shared information, purchasing leverage, distribution economies, and the like--many executives now assume that Internet businesses have to be separate to thrive. They believe that the very nature of traditional business--its protectiveness of current customers, its fear of cannibalization, its general myopia--will smother any Internet initiative. Authors Ranjay Gulati and Jason Garino contend that executives don't have to make an either- or choice when it comes to their clicks-and-mortar strategies. The question isn't, "Should we develop our Internet channel in-house or launch a spin-off?" but rather, "What degree of integration makes sense for our company?" To determine the best level of integration for their companies, executives should examine four business dimensions: brand, management, operations, and equity. Drawing on the experiences of three established retailers--Office Depot, KB Toys, and Rite Aid--the authors show the spectrum of strategies available and discuss the trade-offs involved in each choice. By thinking carefully about which aspects of a business to integrate and which to keep distinct, companies can tailor their clicks-and-mortar strategy to their own particular market and competitive situation, dramatically increasing their odds of e-business success.

  12. Characterisation of a protection level Am-241 calibration source (United States)

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


    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.

  13. Medclic: the Mediterranean in one click (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


    "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}{}) 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,, 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

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

    DEFF Research Database (Denmark)

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


    -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...... scheme, which always inserts two partial shoot-through states per half carrier cycle for smooth balanced operation. Theoretical findings and practical issues identified are eventually verified by constructing a scaled down laboratory prototype for testing....

  15. Evaluating forensic biology results given source level propositions. (United States)

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


    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.

  16. Source Similarity and Social Media Health Messages: Extending Construal Level Theory to Message Sources. (United States)

    Young, Rachel


    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.

  17. Visible-Light-Induced Click Chemistry. (United States)

    Mueller, Jan O; Schmidt, Friedrich G; Blinco, James P; Barner-Kowollik, Christopher


    A rapid and catalyst-free cycloaddition system for visible-light-induced click chemistry is reported. A readily accessible photoreactive 2H-azirine moiety was designed to absorb light at wavelengths above 400 nm. Irradiation with low-energy light sources thus enables efficient small-molecule synthesis with a diverse range of multiple-bond-containing compounds. Moreover, in order to demonstrate the efficiency of the current approach, quantitative ligation of the photoactivatable chromophore with functional polymeric substrates was performed and full conversion with irradiation times of only 1 min at ambient conditions was achieved. The current report thus presents a highly efficient method for applications involving selective cycloaddition to electron-deficient multiple-bond-containing materials.

  18. Urban NH3 levels and sources in a Mediterranean environment (United States)

    Reche, Cristina; Viana, Mar; Pandolfi, Marco; Alastuey, Andrés; Moreno, Teresa; Amato, Fulvio; Ripoll, Anna; Querol, Xavier


    Urban NH3 concentrations were mapped in Barcelona (Spain) by means of passive samplers (dosimeters). Average NH3 levels were 9.5 μg m-3 in summer and 4.4 μg m-3 in winter, higher than those reported in other urban background sites in Europe, this being especially notable in summer. During this season, values were significantly higher at urban background than at traffic sites, probably indicating the impact of emissions from biological sources, such as humans, sewage systems and garbage containers. Thus, the volatilization of NH3 from the aerosol phase seems to be significant enough during summer to dominate over traffic emissions. Conversely, in winter levels were higher at traffic sites, suggesting a contribution from vehicle emissions. Indeed, NH3 levels decreased by 55% with increasing distance (50 m) to the direct emissions from traffic. A significant correlation between NH3 concentrations averaged for the different districts of the city and the number of waste containers per hm2 was also obtained, highlighting the necessity for controlling and reducing the emissions from garbage collection systems. The urban topography of the Barcelona historical city centre, characterised by narrow streets with a high population density, seemed to exert a strong influence on NH3 levels, with levels reaching up to 30 μg m-3 as a consequence of limited dispersion and ventilation conditions. The impact of the sewage system emissions was also detected with an increase of levels when measuring immediately above the source, even though further studies are required to evaluate the relevance of these emissions.

  19. The ZeroAccess Auto-Clicking and Search-Hijacking Click Fraud Modules (United States)


    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


    Institute of Scientific and Technical Information of China (English)

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


    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. 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.

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

    Institute of Scientific and Technical Information of China (English)

    Wang Haishi; Zhang Bo; Sun Jiang


    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.

  3. Radiation efficiency of earthquake sources at different hierarchical levels

    Energy Technology Data Exchange (ETDEWEB)

    Kocharyan, G. G., E-mail: [Institute of Dynamics of Geospheres RAS, Moscow, 119334 (Russian Federation); Moscow Institute of Physics and Technology (State University), Dolgoprudny, 117303 (Russian Federation)


    Such factors as earthquake size and its mechanism define common trends in alteration of radiation efficiency. The macroscopic parameter that controls the efficiency of a seismic source is stiffness of fault or fracture. The regularities of this parameter alteration with scale define several hierarchical levels, within which earthquake characteristics obey different laws. Small variations of physical and mechanical properties of the fault principal slip zone can lead to dramatic differences both in the amplitude of released stress and in the amount of radiated energy.

  4. Using Neural Networks for Click Prediction of Sponsored Search


    Baqapuri, Afroze Ibrahim; Trofimov, Ilya


    Sponsored search is a multi-billion dollar industry and makes up a major source of revenue for search engines (SE). click-through-rate (CTR) estimation plays a crucial role for ads selection, and greatly affects the SE revenue, advertiser traffic and user experience. We propose a novel architecture for solving CTR prediction problem by combining artificial neural networks (ANN) with decision trees. First we compare ANN with respect to other popular machine learning models being used for this ...

  5. Genetic perspectives on the origin of clicks in Bantu languages from southwestern Zambia. (United States)

    Barbieri, Chiara; Butthof, Anne; Bostoen, Koen; Pakendorf, Brigitte


    Some Bantu languages spoken in southwestern Zambia and neighboring regions of Botswana, Namibia, and Angola are characterized by the presence of click consonants, whereas their closest linguistic relatives lack such clicks. As clicks are a typical feature not of the Bantu language family, but of Khoisan languages, it is highly probable that the Bantu languages in question borrowed the clicks from Khoisan languages. In this paper, we combine complete mitochondrial genome sequences from a representative sample of populations from the Western Province of Zambia speaking Bantu languages with and without clicks, with fine-scaled analyses of Y-chromosomal single nucleotide polymorphisms and short tandem repeats to investigate the prehistoric contact that led to this borrowing of click consonants. Our results reveal complex population-specific histories, with female-biased admixture from Khoisan-speaking groups associated with the incorporation of click sounds in one Bantu-speaking population, while concomitant levels of potential Khoisan admixture did not result in sound change in another. Furthermore, the lack of sequence sharing between the Bantu-speaking groups from southwestern Zambia investigated here and extant Khoisan populations provides an indication that there must have been genetic substructure in the Khoisan-speaking indigenous groups of southern Africa that did not survive until the present or has been substantially reduced.

  6. SuFEx Click: New Materials from SOx F and Silyl Ethers. (United States)

    Yatvin, Jeremy; Brooks, Karson; Locklin, Jason


    New forms of click chemistry present new opportunities in materials science. Sulfur(VI) fluoride exchange (SuFEx) is a recently discovered click reaction between molecules containing SOx F groups and silyl ethers, two functionalities that are orthogonal to all other known click chemistries, that generates sulfate or sulfonate connections upon the addition of certain organobases or fluoride sources. SuFEx also has several important advantages over other click reactions in that it is insensitive to ambient oxygen and water, and its precursor materials, especially SOx F, are chemically, UV, and thermally inert. This Concept article focuses on the unique reactivity of SuFEx and its relation to building high molecular weight polymers and surface coatings, both of which make it a powerful new tool for materials science.

  7. One Click: The CECS Students’ Assistant Tools

    Directory of Open Access Journals (Sweden)



    Full Text Available This study is pursued because the researchers believe that the design project is more convenient to use in a group discussion as students are expected to gain more knowledge during peer to peer discussion. Through this study, some issues in the traditional way of teaching will be resolve like the time-consuming checking of attendance, quizzes dictation, paying of test papers and the fear of students to participate in recitation The researchers used Prototyping model as procedural method for the successful development and implementation of the hardware and software. This method has five phases which include: quick plan, quick design, prototype construction, delivery and feedback and communication. This study was evaluated by the CECS Students and the assessment of the respondent regarding the software and hardware application was measured in different levels of acceptability such as Accuracy, Adaptability, Effectiveness, Efficiency, Interactive, Portability, Reliability, Security and User-friendliness. The overall acceptability of the traditional way of teaching as evaluated by the respondents is satisfactory. With regard to the evaluation of One Click: The CECS Students’ Assistant Tool, the overall acceptability is excellent. Through evaluation, the researchers had determined that there is a significant difference between the levels of acceptability of the traditional way of teaching and the “One Click: The CECS Students’ Assistant Tool” in terms of the given set of criteria. The recommendation of the researchers in the design project are as follows: enhance the system where the users/students can go back and answer the previous questions and add an interface where user/instructor can delete files.

  8. A neural click model for web search

    NARCIS (Netherlands)

    Borisov, A.; Markov, I.; de Rijke, M.; Serdyukov, P.


    Understanding user browsing behavior in web search is key to improving web search effectiveness. Many click models have been proposed to explain or predict user clicks on search engine results. They are based on the probabilistic graphical model (PGM) framework, in which user behavior is represented

  9. Applications of click chemistry in radiopharmaceutical development. (United States)

    Walsh, Joseph C; Kolb, Hartmuth C


    Click chemistry, a concept that employs only practical and reliable transformations for compound synthesis, has made a significant impact in several areas of chemistry, including material sciences and drug discovery. The present article describes the use of click chemistry for the development of radiopharmaceuticals. Target templated in situ click chemistry was used for lead generation. The 1,2,3-triazole moiety was found to improve the pharmacokinetic properties of certain radiopharmaceuticals. The reliable Cu(I)-catalyzed click reaction was employed for radiolabeling of peptidic compounds without the need for protecting groups. In summary, the click chemistry approach for the discovery, optimization and labeling of new radiotracers, represents a very powerful tool for radiopharmaceutical development.

  10. Preparing polymeric biomaterials using "click" chemistry techniques (United States)

    Lin, Fei

    Significant efforts have been focused on preparing degradable polymeric biomaterials with controllable properties, which have the potential to stimulate specific cellular responses at the molecular level. Click reactions provide a universal tool box to achieve that goal through molecular level design and modification. This dissertation demonstrates multiple methodologies and techniques to develop advanced biomaterials through combining degradable polymers and click chemistry. In my initial work, a novel class of amino acid-based poly(ester urea)s (PEU) materials was designed and prepared for potential applications in bone defect treatment. PEUs were synthesized via interfacial polycondensation, and showed degradability in vivo and possessed mechanical strength superior to conventionally used polyesters. Further mechanical enhancement was achieved after covalent crosslinking with a short peptide crosslinker derived from osteogenic growth peptide (OGP). The in vitro and in an in vivo subcutaneous rat model demonstrated that the OGP-based crosslinkers promoted proliferative activity of cells and accelerated degradation properties of PEUs. As a continuous study, extra efforts were focused on the development of PEUs with functional pendant groups, including alkyne, azide, alkene, tyrosine phenol, and ketone groups. PEUs with Mw exceeding to 100K Da were obtained via interfacial polycondensation, and the concentration of pendent groups was varied using a copolymerization strategy. Electrospinning was used to fabricate PEU nanofiber matrices with mechanical strengths suitable for tissue engineering. A series of biomolecules were conjugated to nanofiber surface following electrospinning using click reactions in aqueous media. The ability to derivatize PEUs with biological motifs using high efficient chemical reactions will significantly expand their use in vitro and in vivo. Based on similar principles, a series of mono- and multifunctionalized polycaprolactone (PCL

  11. Separation of sperm whale click-trains for multipath rejection. (United States)

    Baggenstoss, Paul M


    In this paper an algorithm is described for grouping sperm whale clicks received at a single hydrophone into click-trains associated with a given whale and propagation path. To accomplish this, features are extracted from pairs of clicks in order to derive a statistical measure of click similarity. Then, the algorithm maximizes a global measure of similarity between the associated clicks. In addition to grouping clicks according to click-trains, it classifies click-trains into a propagation path (direct, surface, bottom reverberation). The propagation path is identified using a combination of (1) a statistical classifier operating on features extracted from individual clicks and (2) the cross-correlation of click-trains to identify the relative time delays. The algorithm is demonstrated on at-sea recorded data, showing the elimination of time-delay ambiguities associated with the reverberation paths observed at sensor pairs.

  12. Flexible Piezoelectric Energy Harvesting from Mouse Click Motions. (United States)

    Cha, Youngsu; Hong, Jin; Lee, Jaemin; Park, Jung-Min; Kim, Keehoon


    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.

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

    DEFF Research Database (Denmark)

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


    -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......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...

  14. New data sources to indicate levels of active citizenship

    NARCIS (Netherlands)

    Rosales Sanchez, C.; Craglia, M.; Bregt, A.K.


    Data availability is a general constraint in the generation of indicators for decision-making processes. Web 2.0 technologies offer new potentials of data sources (also considered as big data sources) that needs to be investigated. In our research we focus on indicators of active citizenship as a re

  15. Click chemistry for rapid labeling and ligation of RNA. (United States)

    Paredes, Eduardo; Das, Subha R


    The copper(I)-promoted azide-alkyne cycloaddition reaction (click chemistry) is shown to be compatible with RNA (with free 2'-hydroxyl groups) in spite of the intrinsic lability of RNA. RNA degradation is minimized through stabilization of the Cu(I) in aqueous buffer with acetonitrile as cosolvent and no other ligand; this suggests the general possibility of "ligandless" click chemistry. With the viability of click chemistry validated on synthetic RNA bearing "click"-reactive alkynes, the scope of the reaction is extended to in-vitro-transcribed or, indeed, any RNA, as a click-reactive azide is incorporated enzymatically. Once clickable groups are installed on RNA, they can be rapidly click labeled or conjugated together in click ligations, which may be either templated or nontemplated. In click ligations the resultant unnatural triazole-linked RNA backbone is not detrimental to RNA function, thus suggesting a broad applicability of click chemistry in RNA biological studies.

  16. One click, two clicks: the past shapes the future in auditory cortex. (United States)

    Fritz, Jonathan; Shamma, Shihab; Elhilali, Mounya


    What are the synaptic and cellular mechanisms by which stimulus context shapes cortical responses? In this issue of Neuron, Wehr and Zador describe intracellular recordings of responses to click pairs in rat primary auditory cortex (A1) and offer new insights into the successive roles of inhibition and synaptic depression in suppressing responses to the second click in many A1 neurons.

  17. MRI Findings in Patients with TMJ Click

    Directory of Open Access Journals (Sweden)

    Mahrokh Imanimoghaddam


    Full Text Available Introduction: It has been shown that joint click, an initial and common finding in internal derangement (ID, respond to neither conservative treatment nor surgical intervention. This raises the question as to whether it must be treated in the absence of other pertinent signs and symptoms, so the aim of this study was to investigate and compare the MRI findings of TMJ in both normal subjects and patients with click, in order to determine the importance of click in predicting TMJ pathological changes. Methods: A total of 26 patients with clinical symptoms of disk displacement with reduction (DDwR according to RDC/TMD were compared to 14 normal subjects in terms of their MRI findings, including disk displacement, effusion, condylar osteoarthritic changes and disk deformities. Results: Out of 80 joints in total (52 affected joints in 26 patients and 28 joints in control group, 48 were shown with normal disk position in MRI whereas 28 (35% and 4 (5% were categorised as DDwR and (disk displacement without reduction DDwoR, respectively. Statistically significant correlations were established between the following pairs of variables in order: Click and disk displacement, effusion and disk displacement, disk displacement and effusion with disk deformity. Conclusion: The correlation between the presence of click and disk displacement, disk deformity and effusion emphasizes the importance of MRI for an accurate diagnosis and development of an appropriate treatment plan in these cases and shows that clinical examination is not sufficient for these purposes.

  18. Levels of Reality as Source of Quantum Indeterminacy

    CERN Document Server

    Nicolescu, Basarab


    We show that the notion of "levels of Reality" introduced by Werner Heisenberg in his "Manuscript of 1942" (1984) and by myself (1983-1985) could explain the quantum indeterminacy. General epistemological implications of this notion are also studied.

  19. Web Image Search Re-ranking with Click-based Similarity and Typicality. (United States)

    Yang, Xiaopeng; Mei, Tao; Zhang, Yong Dong; Liu, Jie; Satoh, Shin'ichi


    In image search re-ranking, besides the well known semantic gap, intent gap, which is the gap between the representation of users' query/demand and the real intent of the users, is becoming a major problem restricting the development of image retrieval. To reduce human effects, in this paper, we use image click-through data, which can be viewed as the "implicit feedback" from users, to help overcome the intention gap, and further improve the image search performance. Generally, the hypothesis visually similar images should be close in a ranking list and the strategy images with higher relevance should be ranked higher than others are widely accepted. To obtain satisfying search results, thus, image similarity and the level of relevance typicality are determinate factors correspondingly. However, when measuring image similarity and typicality, conventional re-ranking approaches only consider visual information and initial ranks of images, while overlooking the influence of click-through data. This paper presents a novel re-ranking approach, named spectral clustering re-ranking with click-based similarity and typicality (SCCST). First, to learn an appropriate similarity measurement, we propose click-based multi-feature similarity learning algorithm (CMSL), which conducts metric learning based on clickbased triplets selection, and integrates multiple features into a unified similarity space via multiple kernel learning. Then based on the learnt click-based image similarity measure, we conduct spectral clustering to group visually and semantically similar images into same clusters, and get the final re-rank list by calculating click-based clusters typicality and withinclusters click-based image typicality in descending order. Our experiments conducted on two real-world query-image datasets with diverse representative queries show that our proposed reranking approach can significantly improve initial search results, and outperform several existing re-ranking approaches.

  20. Click chemistry for the conservation of cellular structures and fluorescent proteins: ClickOx. (United States)

    Löschberger, Anna; Niehörster, Thomas; Sauer, Markus


    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.

  1. Nine Level Inverter with Boost Converter from Renewable Energy Source

    Directory of Open Access Journals (Sweden)

    Maruthu Pandiyan.R


    Full Text Available A new single phase nine level multilevel inverter is proposed. The input to the proposed nine level multilevel inverter is obtained from solar panel . The solar energy obtained from the solar panel is not constant and it varies with times. In order to maintain the constant voltage obtained from the solar panel the boost converter is used to maintain the constant output voltage using MPPT ( Perturb and observe algorithm algorithm. Then the buck boost converter output voltage is stored in the battery bank. Finally the battery energy is connected to the 9 level inverter circuits. The harmonics in the inverter is eliminated by using the fuzzy logic controller. The gate pulse for the multilevel inverter is given by the fuzzy logic controller which in turn reduces the harmonics in the inverter. Then the inverter output is connected to the grid are some application.

  2. Facile design of biomaterials by 'click' chemistry

    DEFF Research Database (Denmark)

    Hvilsted, Søren


    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...

  3. A 6-switch single-phase 5-level current-source inverter

    Institute of Scientific and Technical Information of China (English)

    BAO Jian-yu; LI Yu-ling; ZHANG Zhong-chao


    The new 6-switch single-phase 5-level current-source inverter proposed in this paper was developed by properly simplifying the traditional 8-switch single-phase 5-level current-source inverter, and its operational principle was analyzed. Just like the problem of voltage-unbalance between different levels existing in voltage-source multilevel inverters, a similar problem of current-unbalance between different levels whether for the 8-switch single-phase 5-level current-source inverter, or for the new 6-switch 5-level current-source inverter also exists. A simple current-balance control method via DC current feedback is presented here to implement the current-balance control between different levels. And to reduce the output current harmonics, PWM control technique was used. Simulation and experimental results showed that this new 6-switch topology operates correctly and that the balance-inductor can almost equally distribute the total DC current.

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

    DEFF Research Database (Denmark)

    Li, Xueliang; Gallagher, John Patrick


    Energy efficiency can have a significant influence on user experience of mobile devices such as smartphones and tablets. Although energy is consumed by hardware, software optimization plays an important role in saving energy, and thus software developers have to participate in the optimization...... 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...

  5. 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.


    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 dri

  6. Modeling clicks beyond the first result page

    NARCIS (Netherlands)

    Chuklin, A.; Serdyukov, P.; de Rijke, M.


    Most modern web search engines yield a list of documents of a fixed length (usually 10) in response to a user query. The next ten search results are usually available in one click. These documents either replace the current result page or are appended to the end. Hence, in order to examine more docu

  7. Computer Security: one click and BOOM…

    CERN Multimedia

    Stefan Lueders, Computer Security Team


    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. Application of Click Chemistry for PET

    NARCIS (Netherlands)

    Mirfeizi, Leila; Campbell-Verduyn, Lachlan; Dierckx, Rudi A.; Feringa, Bernard; Elsinga, Philip H.


    Sharpless et al. presented, in 2001, a review in which they introduced the concept of "click chemistry". In this review a "new way" of making chemicals, with a particular emphasis on drugs, is presented. Current drugs are often based on natural products that were first extracted from plants or other

  9. Machine-learning-based diagnosis of schizophrenia using combined sensor-level and source-level EEG features. (United States)

    Shim, Miseon; Hwang, Han-Jeong; Kim, Do-Won; Lee, Seung-Hwan; Im, Chang-Hwan


    Recently, an increasing number of researchers have endeavored to develop practical tools for diagnosing patients with schizophrenia using machine learning techniques applied to EEG biomarkers. Although a number of studies showed that source-level EEG features can potentially be applied to the differential diagnosis of schizophrenia, most studies have used only sensor-level EEG features such as ERP peak amplitude and power spectrum for machine learning-based diagnosis of schizophrenia. In this study, we used both sensor-level and source-level features extracted from EEG signals recorded during an auditory oddball task for the classification of patients with schizophrenia and healthy controls. EEG signals were recorded from 34 patients with schizophrenia and 34 healthy controls while each subject was asked to attend to oddball tones. Our results demonstrated higher classification accuracy when source-level features were used together with sensor-level features, compared to when only sensor-level features were used. In addition, the selected sensor-level features were mostly found in the frontal area, and the selected source-level features were mostly extracted from the temporal area, which coincide well with the well-known pathological region of cognitive processing in patients with schizophrenia. Our results suggest that our approach would be a promising tool for the computer-aided diagnosis of schizophrenia.

  10. Syntheses of Sulfo-Glycodendrimers Using Click Chemistry and Their Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Tomohiro Fukuda


    Full Text Available A series of novel glycol-clusters containing sulfonated N-acetyl-D-glucosamine (GlcNAc have been synthesized using click chemistry. Three dendrimers with aromatic dendrons were synthesized using chlorination, azidation and click chemistries. The resulting dendrimers were modified with azide-terminated sulfonated GlcNAc using click chemistry. The sulfonated dendrimers showed affinity for proteins, including the lectin wheat germ agglutinin and amyloid beta peptide (1-42. The dendrimers of G1 and G2 in particular showed the largest affinity for the proteins. The addition of the sulfonated GlcNAc dendrimers of G1 and G2 exhibited an inhibition effect on the aggregation of the amyloid beta peptide, reduced the b-sheet conformation, and led to a reduction in the level of nanofiber formation.

  11. Design and comparison of three-level three-phase T-source inverters

    DEFF Research Database (Denmark)

    Shults, T.; Husev, Oleksandr; Blaabjerg, Frede


    This paper presents guidelines for component design of recently proposed topologies of the three-level three-phase T-source inverters. Two different topologies are considered: T-source inverters with discontinuous input current and T-source inverters with continuous input current. Steady state...

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

    DEFF Research Database (Denmark)

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


    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...... harmonic performance, the proposed modulation schemes of four-leg three-level Z-source inverters can satisfy the expected buck-boost operation under unbalanced modulation conditions. Except of the modulation complexity hidden in the four-leg inverters, five-phase three-level Z-source inverters show totally...... 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...

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

    DEFF Research Database (Denmark)

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


    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...... characteristics of a Z-source inverter, in addition to its usual voltage-buck operation. By focusing on specific types of three-level Z-source inverters, it can also be shown that, for the dual Z-source inverters, a unique feature accompanying it is its extra ability to force common-mode voltage to zero even...

  14. The simulation of click and double-click through EMG signals. (United States)

    Pinheiro, Carlos G; Andrade, Adriano O


    Patients with severe motor impairments, victims of stroke, amyotrophic lateral sclerosis and spinal cord injury are prevented from oral and gesture communication, demanding alternative channels and methods of communication, possibly using a computer. In order to obtain the complete emulation of a standard mouse, the single-click and double-click actions are desirable functionalities. In this study, the implementation of such actions is executed by the analysis of the electromyographic signal recorded from the Frontalis muscle. Muscle activity is discriminated from noise and this information is used to feed a state-machine that in turn decides which action is intended. The method uses an adaptive threshold, which offers freedom for the selection of the parameters of the system. The rate of successfully detected commands found was up to 100% for the single-click and 92% for the double-click. Even though good results were found for double-clicks, the experiment indicate muscle fatigue in the short term. The time response found was below 300 ms suggesting real-time implementation is feasible. Also, other devices can be operated with this approach, if it is accepted as a two symbols system generator.

  15. In vivo targeting through click chemistry. (United States)

    Brudno, Yevgeny; Desai, Rajiv M; Kwee, Brian J; Joshi, Neel S; Aizenberg, Michael; Mooney, David J


    Targeting small molecules to diseased tissues as therapy or diagnosis is a significant challenge in drug delivery. Drug-eluting devices implanted during invasive surgery allow the controlled presentation of drugs at the disease site, but cannot be modified once the surgery is complete. We demonstrate that bioorthogonal click chemistry can be used to target circulating small molecules to hydrogels resident intramuscularly in diseased tissues. We also demonstrate that small molecules can be repeatedly targeted to the diseased area over the course of at least one month. Finally, two bioorthogonal reactions were used to segregate two small molecules injected as a mixture to two separate locations in a mouse disease model. These results demonstrate that click chemistry can be used for pharmacological drug delivery, and this concept is expected to have applications in refilling drug depots in cancer therapy, wound healing, and drug-eluting vascular grafts and stents.

  16. Direct calibration of click-counting detectors (United States)

    Bohmann, M.; Kruse, R.; Sperling, J.; Silberhorn, C.; Vogel, W.


    We introduce and experimentally implement a method for the detector calibration of photon-number-resolving time-bin multiplexing layouts based on the measured click statistics of superconducting nanowire detectors. In particular, the quantum efficiencies, the dark count rates, and the positive operator-valued measures of these measurement schemes are directly obtained with high accuracy. The method is based on the moments of the click-counting statistics for coherent states with different coherent amplitudes. The strength of our analysis is that we can directly conclude—on a quantitative basis—that the detection strategy under study is well described by a linear response function for the light-matter interaction and that it is sensitive to the polarization of the incident light field. Moreover, our method is further extended to a two-mode detection scenario. Finally, we present possible applications for such well-characterized detectors, such as sensing of atmospheric loss channels and phase sensitive measurements.

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

    DEFF Research Database (Denmark)

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


    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......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...

  18. 18F-Labeling Using Click Cycloadditions

    Directory of Open Access Journals (Sweden)

    Kathrin Kettenbach


    Full Text Available Due to expanding applications of positron emission tomography (PET there is a demand for developing new techniques to introduce fluorine-18 (t1/2=109.8 min. Considering that most novel PET tracers are sensitive biomolecules and that direct introduction of fluorine-18 often needs harsh conditions, the insertion of 18F in those molecules poses an exceeding challenge. Two major challenges during 18F-labeling are a regioselective introduction and a fast and high yielding way under mild conditions. Furthermore, attention has to be paid to functionalities, which are usually present in complex structures of the target molecule. The Cu-catalyzed azide-alkyne cycloaddition (CuAAC and several copper-free click reactions represent such methods for radiolabeling of sensitive molecules under the above-mentioned criteria. This minireview will provide a quick overview about the development of novel 18F-labeled prosthetic groups for click cycloadditions and will summarize recent trends in copper-catalyzed and copper-free click 18F-cycloadditions.

  19. Peptidyl Materials Formed Through Click Chemistry Enhanced Coiled-Coil Interactions (United States)

    Koehler, Kenneth


    Biologically derived materials offer a level of sophistication synthetically fabricated materials have only attempted to mimic. This level of complexity may be found in materials such as peptides. Implementing new theory and modeling, peptides with the propensity to form coiled-coil (CC) bundles were designed and synthesized. Through the use of this de novo approach, modeling allowed prediction of the feasibility to include non-natural amino acids conducive to click chemistry into the peptide. Amino acids showcasing thiol or alkyne functionalities were considered owing to the ability of these moieties to participate in the thiol-ene and copper click reactions respectively. Once synthesized, the peptides decorated with these clickable motifs were placed in solution and allowed to self-assemble into CC's. CD spectroscopy and DLS experiments confirmed the formation and assembly of CC's. Click reactions were then incited to link the CC assemblies together and form a network with predictable dimensionality and pore size between CC bundles. To incite network formation, click reactions between CC side chain residues and suitably functionalized crosslinkers were implemented. The linking of coiled-coils and material formation were assessed using DLS and TEM.

  20. The impact of carbohydrate and protein level and sources on swine manure foaming properties (United States)

    This study explored the impact of swine diet on the composition, methane production potential, and foaming properties of manure. Samples of swine manure were collected from controlled feeding trials with diets varying in protein and carbohydrate levels and sources. Protein sources consisted of corn ...

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

    DEFF Research Database (Denmark)

    Verhulst, Sarah; Harte, James; Dau, Torsten


    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. The ...... phenomenologically using compression or expansion of the system output. This was obtained by shifting the operating-point on the input-output-characteristic in relation to the ICI....

  2. Using Click Chemistry to Identify Potential Drug Targets in Plasmodium (United States)


    AWARD NUMBER: W81XWH-13-1-0429 TITLE: Using "Click Chemistry " to Identify Potential Drug Targets in Plasmodium PRINCIPAL INVESTIGATOR...29Mar2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER W81XWH-13-1-0429 Using click chemistry to identify potential drug targets in Plasmodium 5b...Al-Tsp derivatives begins. Two classes of Tsp derivatives (Al-Tsp) are appropriate for click chemistry (Fig. 1). Class I derivatives carry a

  3. Assessment of sanitation levels of sources of water in Osun State Capital, Nigeria

    Directory of Open Access Journals (Sweden)

    Felix A. Oginni


    Full Text Available A study of the physicochemical and bacteriological analysis including BOD and COD was carried out for sources of water in Oshogbo the Capital of the State of Osun. Seven water sampling areas were selected to cover the low, medium and high population density areas of the State Capital. Water samples were collected from five sources of water, namely, shallow well, borehole, stream, rain and river. Water samples were collected from the well, borehole and stream water sources from Dada Estate and Isale Oshun for low density population, Ayetoro, Ogo-Oluwa and Oke-Ayepe for medium density, and Oke-Bale and Igbona for high density population areas. Three sampling points were undertaken for the rain water source while River Oshun source at Isale-Oshun was the 25th water sampling point. A total of 25 water quality parameters were analyzed for each of the 25 water sources sampled using the facility at the Rural Water And Environmental Sanitation Agency, RUWESA in Osun State Government Secretariat in Abere. Results indicated that 8 of the water quality parameters, pH, Turbidity; Magnesium hardness, Free Chlorine, Nitrite, Bacteriological, BOD and COD were not within Standards Organization of Nigeria (SON permitted water quality standards and are of concern to sanitation of potable water in the State Capital. The level of each parameter differs from source to source as well as from level of population densities. The sources that were adjudged polluted were Ogo-Oluwa and Oke-Ayepe well sources; Ogo-Oluwa, Oke-Bale and Igbona stream sources Oke-Bale Rain source.R and the River source at Isale-Oshun. The polluted sources are all within the medium and high population density areas of the State Capital.

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

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, P.C.; Vilathgamuwa, D.M.;


    This paper proposes various compensation methods for three-level Z-source inverters under semiconductor failure conditions. Unlike the traditional fault tolerant techniques in three-level inverter by using either an additional phase-leg or collective switching states, the proposed methods simply ...

  5. 10 CFR 34.21 - Limits on external radiation levels from storage containers and source changers. (United States)


    ... 10 Energy 1 2010-01-01 2010-01-01 false Limits on external radiation levels from storage... INDUSTRIAL RADIOGRAPHY AND RADIATION SAFETY REQUIREMENTS FOR INDUSTRIAL RADIOGRAPHIC OPERATIONS Equipment § 34.21 Limits on external radiation levels from storage containers and source changers. The...

  6. Auditory brainstem responses for click and CE-chirp stimuli in individuals with and without occupational noise exposure

    Directory of Open Access Journals (Sweden)

    Zeena Venkatacheluvaiah Pushpalatha


    Full Text Available Introduction: Encoding of CE-chirp and click stimuli in auditory system was studied using auditory brainstem responses (ABRs among individuals with and without noise exposure. Materials and Methods: The study consisted of two groups. Group 1 (experimental group consisted of 20 (40 ears individuals exposed to occupational noise with hearing thresholds within 25 dB HL. They were further divided into three subgroups based on duration of noise exposure (0–5 years of exposure-T1, 5–10 years of exposure-T2, and >10 years of exposure-T3. Group 2 (control group consisted of 20 individuals (40 ears. Absolute latency and amplitude of waves I, III, and V were compared between the two groups for both click and CE-chirp stimuli. T1, T2, and T3 groups were compared for the same parameters to see the effect of noise exposure duration on CE-chirp and click ABR. Result: In Click ABR, while both the parameters for wave III were significantly poorer for the experimental group, wave V showed a significant decline in terms of amplitude only. There was no significant difference obtained for any of the parameters for wave I. In CE-Chirp ABR, the latencies for all three waves were significantly prolonged in the experimental group. However, there was a significant decrease in terms of amplitude in only wave V for the same group. Discussion: Compared to click evoked ABR, CE-Chirp ABR was found to be more sensitive in comparison of latency parameters in individuals with occupational noise exposure. Monitoring of early pathological changes at the brainstem level can be studied effectively by using CE-Chirp stimulus in comparison to click stimulus. Conclusion: This study indicates that ABR’s obtained with CE-chirp stimuli serves as an effective tool to identify the early pathological changes due to occupational noise exposure when compared to click evoked ABR.

  7. Click reaction: An applicable radiolabeling method for molecular imaging

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Ji Young; Lee, Byung Chul [Dept. of Nuclear Medicine, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Sungnam (Korea, Republic of)


    In recent years, the click reaction has found rapidly growing applications in the field of radiochemistry, ranging from a practical labeling method to molecular imaging of biomacromolecules. This present review details the development of highly reliable, powerful and selective click chemistry reactions for the rapid synthesis of new radiotracers for molecular imaging.

  8. Metal-Free Click Chemistry Reactions on Surfaces

    NARCIS (Netherlands)

    Escorihuela, J.; Marcelis, A.T.M.; Zuilhof, H.


    In the last decade, interest in the functionalization of surfaces and materials has increased dramatically. In this regard, click chemistry deserves a central focus because of its mild reaction conditions, high efficiency, and easy post-treatment. Among such novel click reactions, those that do not

  9. Modular ‘Click-in-Emulsion’ Bone-Targeted Nanogels (United States)

    Heller, Daniel A.; Levi, Yair; Pelet, Jeisa M.; Doloff, Joshua C.; Wallas, Jasmine; Pratt, George W.; Jiang, Shan; Sahay, Gaurav; Schroeder, Avi; Schroeder, Josh E.; Chyan, Yieu; Zurenko, Christopher; Querbes, William; Manzano, Miguel; Kohane, Daniel S.; Langer, Robert; Anderson, Daniel G.


    A new class of nanogel demonstrates modular biodistribution and affinity for bone. Nanogels, 67 nm in diameter and synthesized via an astoichiometric click-chemistry-inemulsion method, controllably display residual, free click-able functional groups. Functionalization with a bisphosphonate ligand results in significant binding to bone on the inner walls of marrow cavities, liver avoidance, and anti-osteoporotic effects. PMID:23280931

  10. Versatile click alginate hydrogels crosslinked via tetrazine-norbornene chemistry. (United States)

    Desai, Rajiv M; Koshy, Sandeep T; Hilderbrand, Scott A; Mooney, David J; Joshi, Neel S


    Alginate hydrogels are well-characterized, biologically inert materials that are used in many biomedical applications for the delivery of drugs, proteins, and cells. Unfortunately, canonical covalently crosslinked alginate hydrogels are formed using chemical strategies that can be biologically harmful due to their lack of chemoselectivity. In this work we introduce tetrazine and norbornene groups to alginate polymer chains and subsequently form covalently crosslinked click alginate hydrogels capable of encapsulating cells without damaging them. The rapid, bioorthogonal, and specific click reaction is irreversible and allows for easy incorporation of cells with high post-encapsulation viability. The swelling and mechanical properties of the click alginate hydrogel can be tuned via the total polymer concentration and the stoichiometric ratio of the complementary click functional groups. The click alginate hydrogel can be modified after gelation to display cell adhesion peptides for 2D cell culture using thiol-ene chemistry. Furthermore, click alginate hydrogels are minimally inflammatory, maintain structural integrity over several months, and reject cell infiltration when injected subcutaneously in mice. Click alginate hydrogels combine the numerous benefits of alginate hydrogels with powerful bioorthogonal click chemistry for use in tissue engineering applications involving the stable encapsulation or delivery of cells or bioactive molecules.

  11. Recurrent Embolic Strokes of Undetermined Source in a Patient with Extreme Lipoprotein(a) Levels. (United States)

    Bulwa, Zachary; Kim, Audrey; Singh, Karandeep; Kantorovich, Alexander; Suhail, Faten


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wilhite, E.L.


    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.

  13. Extracranial sources of S100B do not affect serum levels.

    Directory of Open Access Journals (Sweden)

    Nancy Pham

    Full Text Available S100B, established as prevalent protein of the central nervous system, is a peripheral biomarker for blood-brain barrier disruption and often also a marker of brain injury. However, reports of extracranial sources of S100B, especially from adipose tissue, may confound its interpretation in the clinical setting. The objective of this study was to characterize the tissue specificity of S100B and assess how extracranial sources of S100B affect serum levels. The extracranial sources of S100B were determined by analyzing nine different types of human tissues by ELISA and Western blot. In addition, brain and adipose tissue were further analyzed by mass spectrometry. A study of 200 subjects was undertaken to determine the relationship between body mass index (BMI and S100B serum levels. We also measured the levels of S100B homo- and heterodimers in serum quantitatively after blood-brain barrier disruption. Analysis of human tissues by ELISA and Western blot revealed variable levels of S100B expression. By ELISA, brain tissue expressed the highest S100B levels. Similarly, Western blot measurements revealed that brain tissue expressed high levels of S100B but comparable levels were found in skeletal muscle. Mass spectrometry of brain and adipose tissue confirmed the presence of S100B but also revealed the presence of S100A1. The analysis of 200 subjects revealed no statistically significant relationship between BMI and S100B levels. The main species of S100B released from the brain was the B-B homodimer. Our results show that extracranial sources of S100B do not affect serum levels. Thus, the diagnostic value of S100B and its negative predictive value in neurological diseases in intact subjects (without traumatic brain or bodily injury from accident or surgery are not compromised in the clinical setting.

  14. Source level estimation of two blue whale subspecies in southwestern Indian Ocean. (United States)

    Samaran, Flore; Guinet, Christophe; Adam, Olivier; Motsch, Jean-François; Cansi, Yves


    Blue whales produce intense, stereotypic low frequency calls that are particularly well suited for transmission over long distances. Because these calls vary geographically, they can be used to gain insight into subspecies distribution. In the Southwestern Indian Ocean, acoustic data from a triad of calibrated hydrophones maintained by the International Monitoring System provided data on blue whale calls from two subspecies: Antarctic and pygmy blue whales. Using time difference of arrival and least-squares hyperbolic methods, the range and location of calling whales were determined. By using received level of calls and propagation modeling, call source levels of both subspecies were estimated. The average call source level was estimated to 179+/-5 dB re 1 microPa(rms) at 1 m over the 17-30 Hz band for Antarctic blue whale and 174+/-1 dB re 1 microPa(rms) at 1 m over the 17-50 Hz band for pygmy blue whale. According to previous estimates, slight variations in the source level could be due to inter-individual differences, inter-subspecies variations and the calculation method. These are the first reported source level estimations for blue whales in the Indian Ocean. Such data are critical to estimate detection ranges of calling blue whales.

  15. Analysis of Current Source PWM Inverter for Different Levels with No-Insulating Switching Device

    Directory of Open Access Journals (Sweden)

    Kumar Abhishek


    Full Text Available This paper gives the new set-up of inverter having DC current source (CSI having no insulated switching device. In the proposed new CSI topology every switching device are connected across a common-source level, thus a single power supply gate drive circuit is required and no insulated power supply and the customary bootstrap circuit is applied. This CSI topology is even legitimate for utmost level of current waveform output, where the power switches number increases. As a turn up, gate drive complexity is reduced, and it also eliminates the cost of capacitors and transformers in switching devices, driver circuits. In addition, this new topology of current-source PWM inverter (CSI can operate even at utmost switching frequency, as every switches will be connected across a common source level. In this paper the different level of proposed CSI operation principle, its design using computer simulation (MATLAB with its total harmonic distortion (THD is analyzed. The computer simulation using MATLAB determines the feasibility of this topology with the analysis of different level which results in reduction of its complexity and the physical size.

  16. Dietary TAG source and level affect performance and lipase expression in larval sea bass (Dicentrarchus labrax)



    The influence of dietary TAG source (fish oil, triolein, and coconut oil) and level (7.5 and 15% of the diet) on growth, lipase activity, and mRNA level was studied in sea bass larvae, from mouth opening until day 24 and from day 37 to 52. Fish oil and triolein induced better growth in both experiments, this being significant at a higher dietary level. Coconut oil significantly decreased growth at the higher level, possibly as the result of an excessive supply of medium-chain TAG. Growth was ...

  17. 'Megapclicks': acoustic click trains and buzzes produced during night-time foraging of humpback whales (Megaptera novaeangliae). (United States)

    Stimpert, Alison K; Wiley, David N; Au, Whitlow W L; Johnson, Mark P; Arsenault, Roland


    Humpback whales (Megaptera novaeangliae) exhibit a variety of foraging behaviours, but neither they nor any baleen whale are known to produce broadband clicks in association with feeding, as do many odontocetes. We recorded underwater behaviour of humpback whales in a northwest Atlantic feeding area using suction-cup attached, multi-sensor, acoustic tags (DTAGs). Here we describe the first recordings of click production associated with underwater lunges from baleen whales. Recordings of over 34000 'megapclicks' from two whales indicated relatively low received levels at the tag (between 143 and 154dB re 1 microPa pp), most energy below 2kHz, and interclick intervals often decreasing towards the end of click trains to form a buzz. All clicks were recorded during night-time hours. Sharp body rolls also occurred at the end of click bouts containing buzzes, suggesting feeding events. This acoustic behaviour seems to form part of a night-time feeding tactic for humpbacks and also expands the known acoustic repertoire of baleen whales in general.

  18. Correlation Correlation of Blood Lead Levels, Anemia and Water Source in Children


    Gurukripa, Sowmya Sanjeeva; Shetty, Anil


    Background: Exposure to lead and its consequences is a health risk frequently encountered in developing countries.Aims & Objectives: This study was undertaken to ascertain whether the source of water poses a risk for high blood levels and consequently anemia.Material & Methods: 30 children with proven anemia and an equal number of children without anemia were enrolled in the study and an atomic absorption spectrophotometer was used to analyse and quantify their blood lead levels. Thei...

  19. Levels, Composition and Sources of PM in the Mexico City Metropolitan Area During the MILAGRO Campaign (United States)

    Querol, X.; Pey, J.; Minguillon, M. C.; Perez, N.; Alastuey, A.; Moreno, T.; Bernabe, R.; Blanco, S.; Cardenas, B.


    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

  20. Preventing IP Source Address Spoofing: A Two-Level,State Machine-Based Method

    Institute of Scientific and Technical Information of China (English)

    BI Jun; LIU Bingyang; WU Jianping; SHEN Yan


    A signature-and-verification-based method, automatic peer-to-peer anti-spoofing (APPA), is pro-posed to prevent IP source address spoofing. In this method, signatures are tagged into the packets at the source peer, and verified and removed at the verification peer where packets with incorrect signatures are filtered. A unique state machine, which is used to generate signatures, is associated with each ordered pair of APPA peers. As the state machine automatically transits, the signature changes accordingly. KISS ran-dom number generator is used as the signature generating algorithm, which makes the state machine very small and fast and requires very low management costs. APPA has an intre-AS (autonomous system) level and an inter-AS level. In the intra-AS level, signatures are tagged into each departing packet at the host and verified at the gateway to achieve finer-grained anti-spoofing than ingress filtering. In the inter-AS level, signatures are tagged at the source AS border router and verified at the destination AS border muter to achieve prefix-level anti-spoofing, and the automatic state machine enables the peers to change signatures without negotiation which makes APPA attack-resilient compared with the spoofing prevention method. The results show that the two levels are both incentive for deployment, and they make APPA an integrated anti-spoofing solution.

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

    DEFF Research Database (Denmark)

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


    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...... can function with the minimum of six device commutations per half carrier cycle (similar to that needed by a traditional buck three-level NPC inverter), while producing the correct volt-sec average and inductive voltage boosting at their ac output terminals. Physically, the designed modulation scheme...

  2. 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


    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.

  3. Blue and fin whale call source levels and propagation range in the Southern Ocean. (United States)

    Sirović, Ana; Hildebrand, John A; Wiggins, Sean M


    Blue (Balaenoptera musculus) and fin whales (B. physalus) produce high-intensity, low-frequency calls, which probably function for communication during mating and feeding. The source levels of blue and fin whale calls off the Western Antarctic Peninsula were calculated using recordings made with calibrated, bottom-moored hydrophones. Blue whales were located up to a range of 200 km using hyperbolic localization and time difference of arrival. The distance to fin whales, estimated using multipath arrivals of their calls, was up to 56 km. The error in range measurements was 3.8 km using hyperbolic localization, and 3.4 km using multipath arrivals. Both species produced high-intensity calls; the average blue whale call source level was 189+/-3 dB re:1 microPa-1 m over 25-29 Hz, and the average fin whale call source level was 189+/-4 dB re:1 microPa-1 m over 15-28 Hz. Blue and fin whale populations in the Southern Ocean have remained at low numbers for decades since they became protected; using source level and detection range from passive acoustic recordings can help in calculating the relative density of calling whales.

  4. On the dependence of the two-level source function on its radiation field. (United States)

    Steinitz, R.; Shine, R. A.


    The consequences of the universally made assumption that the stimulated emission profile is identical to the absorption profile are quantitatively investigated for a two-level atom with Doppler redistribution. The nonlinear terms arising in the source function are evaluated iteratively. We find that the magnitude of the effects is probably completely negligible for visible and UV solar lines.

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

    DEFF Research Database (Denmark)

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


    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, re...

  6. OneClick: A Program for Designing Focused Mutagenesis Experiments

    Directory of Open Access Journals (Sweden)

    Mark Warburton


    Full Text Available OneClick is a user-friendly web-based program, developed specifically for quick-and-easy design of focused mutagenesis experiments (e.g., site-directed mutagenesis and saturation mutagenesis. Written in Perl and developed into a web application using CGI programming, OneClick offers a step-by-step experimental design, from mutagenic primer design to analysis of a mutant library. Upon input of a DNA sequence encoding the protein of interest, OneClick designs the mutagenic primers according to user input, e.g., amino acid position to mutate, type of amino acid substitutions (e.g., substitution to a group of amino acids with similar chemical property and type of mutagenic primers. OneClick has incorporated an extensive range of commercially available plasmids and DNA polymerases suitable for focused mutagenesis. Therefore, OneClick also provides information on PCR mixture preparation, thermal cycling condition, expected size of PCR product and agar plate to use during bacterial transformation. Importantly, OneClick also carries out a statistical analysis of the resultant mutant library, information of which is important for selection/screening. OneClick is a unique and invaluable tool in the field of protein engineering, allowing for systematic construction of a mutant library or a protein variant and simplifying molecular biology work. The program will be constantly updated to reflect the rapid development in the fields of molecular biology and protein engineering.

  7. Conductive Polymer Functionalization by Click Chemistry

    DEFF Research Database (Denmark)

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


    , with reaction times of '"'-'20 h. The applicability of the method is illustrated by coupling of two other alkynes: a short chain fluorocarbon and a MPEG 5000 to the conductive polymer; this alters the advancing water contact angle of the surface by +20° and -20°/-25°, respectively. The targeted chemical surface......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...... to functionalize films of PEDOT-N3 and copolymers prepared from EDOT-N3 and 3,4-ethylenedioxythiophene (EDOT). This approach enables new functionalities on PEDOT that could otherwise not withstand the polymerization conditions. Reactions on the thin polymer films have been optimized using an alkynated fluorophore...

  8. Juicer Provides a One-Click System for Analyzing Loop-Resolution Hi-C Experiments. (United States)

    Durand, Neva C; Shamim, Muhammad S; Machol, Ido; Rao, Suhas S P; Huntley, Miriam H; Lander, Eric S; Aiden, Erez Lieberman


    Hi-C experiments explore the 3D structure of the genome, generating terabases of data to create high-resolution contact maps. Here, we introduce Juicer, an open-source tool for analyzing terabase-scale Hi-C datasets. Juicer allows users without a computational background to transform raw sequence data into normalized contact maps with one click. Juicer produces a hic file containing compressed contact matrices at many resolutions, facilitating visualization and analysis at multiple scales. Structural features, such as loops and domains, are automatically annotated. Juicer is available as open source software at

  9. Effect of lipid sources and inclusion levels in diets for broiler chickens

    Directory of Open Access Journals (Sweden)

    G.V. Polycarpo


    Full Text Available This research aimed to evaluate the interactions and effects of 2 and 4% addition levels of poultry slaughterhouse fat (chicken tallow and soybean oil in diets for broiler chickens. Two experiments were carried out using one-day-old male Cobb chicks in an entirely random design with a 2x2 factorial scheme. In the first experiment, 560 chicks were used to evaluate performance and carcass characteristics. In the second experiment, 100 chicks were used to determine the nutrient digestibility, dietary energy utilization and the lipase and amylase pancreatic activity. There was no interaction between the fat sources and the addition levels for any of the analyzed variables, except for the digestibility coefficient of dry matter (DCDM, which was higher in diets added with 2% soybean oil when compared to chicken tallow. The addition of 4% fat in the diet, regardless of fat source, improved the digestibility coefficient of ethereal extract (DCEE and increased weight gain and feed intake. Moreover, in the initial phase, the addition of 4% fat to the diet increased lipase activity when compared to diets with 2% addition, and a positive correlation between DCEE and pancreatic lipase activity was observed. In conclusion, there is no interaction between fat sources and addition levels, except for DCDM. Carcass characteristics are not influenced by any of the studied factors. The addition of 4% fat increases pancreatic lipase activity and improves DCEE, resulting in greater weight gain, regardless of the tested fat source, making chicken tallow a great alternative to soybean oil.

  10. Determination of the subcriticality level using the {sup 252}Cf source-detector method

    Energy Technology Data Exchange (ETDEWEB)

    Baeten, P. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Lafuente, A., E-mail: anlafuente@etsii.upm.e [Universidad Politecnica de Madrid, 28006 Madrid (Spain); Janssens, J.; Kochetkov, A. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium); Pazsit, I. [Chalmers University of Technology, SE-412 96 Goteborg (Sweden); Van Grieken, G.; Van den Eynde, G. [SCK-CEN, Boeretang 200, B-2400 Mol (Belgium)


    Measurement and monitoring of reactivity in a subcritical state, e.g. during the loading of a power reactor, has a clear safety relevance. The methods currently available for the measurement of k{sub eff} in stationary subcritical conditions should be improved as they refer to the critical state. This is also very important in the framework of ADS (accelerator driven systems) where the measurement of a subcritical level without knowledge of the critical state is looked for. An alternative way to achieve this is by mean of the {sup 252}Cf source-detector method. The method makes use of three detectors inserted in the reactor: two 'ordinary' neutron detectors and one {sup 252}Cf source-detector which contains a small amount of {sup 252}Cf that introduces neutrons in the system through spontaneous fission. By observing fissions through the detection system and correlating the signals of the three detectors, the reactivity rho (and hence the multiplication factor k) can be determined. Before the actual measurements took place, a suitable data acquisition system was realized in order to process the signals and compute the auto and cross power spectral densities. The measurements were then performed in the VENUS reactor, using the {sup 252}Cf source-detector and two BF{sub 3} neutron detectors. The multiplication factor was determined using the Cf source method and compared with measurements using other methods and with computational results (Monte Carlo simulations). The Cf method was benchmarked at a UOX core to other experimental methods that used the critical state as reference and to calculations. Afterwards, the Cf source technique was analyzed in a MOX core to study the possible impact of a significant intrinsic source on the results. This benchmarking gives the possibility to validate the Cf method as a reliable technique for the measurement of subcritical levels in steady state and for cores with an intrinsic source like MOX or burnt fuel cores.

  11. Predicting clicks of PubMed articles. (United States)

    Mao, Yuqing; Lu, Zhiyong


    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.

  12. Recurrent Embolic Strokes of Undetermined Source in a Patient with Extreme Lipoprotein(a Levels

    Directory of Open Access Journals (Sweden)

    Zachary Bulwa


    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.

  13. Retrospectively supervised click decoder calibration for self-calibrating point-and-click brain-computer interfaces. (United States)

    Jarosiewicz, Beata; Sarma, Anish A; Saab, Jad; Franco, Brian; Cash, Sydney S; Eskandar, Emad N; Hochberg, Leigh R


    Brain-computer interfaces (BCIs) aim to restore independence to people with severe motor disabilities by allowing control of acursor on a computer screen or other effectors with neural activity. However, physiological and/or recording-related nonstationarities in neural signals can limit long-term decoding stability, and it would be tedious for users to pause use of the BCI whenever neural control degrades to perform decoder recalibration routines. We recently demonstrated that a kinematic decoder (i.e. a decoder that controls cursor movement) can be recalibrated using data acquired during practical point-and-click control of the BCI by retrospectively inferring users' intended movement directions based on their subsequent selections. Here, we extend these methods to allow the click decoder to also be recalibrated using data acquired during practical BCI use. We retrospectively labeled neural data patterns as corresponding to "click" during all time bins in which the click log-likelihood (decoded using linear discriminant analysis, or LDA) had been above the click threshold that was used during real-time neural control. We labeled as "non-click" those periods that the kinematic decoder's retrospective target inference (RTI) heuristics determined to be consistent with intended cursor movement. Once these neural activity patterns were labeled, the click decoder was calibrated using standard supervised classifier training methods. Combined with real-time bias correction and baseline firing rate tracking, this set of "retrospectively labeled" decoder calibration methods enabled a BrainGate participant with amyotrophic lateral sclerosis (T9) to type freely across 11 research sessions spanning 29days, maintaining high-performance neural control over cursor movement and click without needing to interrupt virtual keyboard use for explicit calibration tasks. By eliminating the need for tedious calibration tasks with prescribed targets and pre-specified click times, this

  14. Effect of High-Pass Filtering on the Neonatal Auditory Brainstem Response to Air- and Bone-Conducted Clicks. (United States)

    Stuart, Andrew; Yang, Edward Y.


    Simultaneous 3- channel recorded auditory brainstem responses (ABR) were obtained from 20 neonates with various high-pass filter settings and low intensity levels. Results support the advocacy of less restrictive high-pass filtering for neonatal and infant ABR screening to air-conducted and bone-conducted clicks. (Author/JDD)

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

    Directory of Open Access Journals (Sweden)

    Liliana Alves


    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.

  16. Click chemistry, a potent tool in medicinal sciences. (United States)

    Musumeci, F; Schenone, S; Desogus, A; Nieddu, E; Deodato, D; Botta, L


    This review focuses on the application of click chemistry in medicinal sciences, and particularly on its role in drug discovery. Because of its high modularity, click chemistry helps to accelerate the current drug discovery process, which relies on massive screening of chemical libraries. This article describes examples of click chemistry applications that are aimed at finding new lead candidates against pathologies such as cancer, AIDS and Alzheimer's disease, and explores the impact that the technique could have in therapy and prevention in the near future, through application in drug delivery systems, bioconjugation and diagnostic. An introduction, addressed to researchers who intend to use this methodology, examines the opportunities to perform click reactions according to the most common and best studied techniques, such as synthesis in water, on solid phase, and under microwave or ultrasound irradiation. Every topic is furnished with examples which have appeared in the literature in the last five years and is clarified by schemes and figures.

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

    Directory of Open Access Journals (Sweden)

    Xiu Zhang


    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.

  18. Applications of azide-based bioorthogonal click chemistry in glycobiology. (United States)

    Zhang, Xiu; Zhang, Yan


    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.

  19. Click Chemistry in Peptide-Based Drug Design

    Directory of Open Access Journals (Sweden)

    Irwin Chaiken


    Full Text Available Click chemistry is an efficient and chemoselective synthetic method for coupling molecular fragments under mild reaction conditions. Since the advent in 2001 of methods to improve stereochemical conservation, the click chemistry approach has been broadly used to construct diverse chemotypes in both chemical and biological fields. In this review, we discuss the application of click chemistry in peptide-based drug design. We highlight how triazoles formed by click reactions have been used for mimicking peptide and disulfide bonds, building secondary structural components of peptides, linking functional groups together, and bioconjugation. The progress made in this field opens the way for synthetic approaches to convert peptides with promising functional leads into structure-minimized and more stable forms.

  20. Click chemistry in peptide-based drug design. (United States)

    Li, Huiyuan; Aneja, Rachna; Chaiken, Irwin


    Click chemistry is an efficient and chemoselective synthetic method for coupling molecular fragments under mild reaction conditions. Since the advent in 2001 of methods to improve stereochemical conservation, the click chemistry approach has been broadly used to construct diverse chemotypes in both chemical and biological fields. In this review, we discuss the application of click chemistry in peptide-based drug design. We highlight how triazoles formed by click reactions have been used for mimicking peptide and disulfide bonds, building secondary structural components of peptides, linking functional groups together, and bioconjugation. The progress made in this field opens the way for synthetic approaches to convert peptides with promising functional leads into structure-minimized and more stable forms.

  1. Recent advances in click chemistry applied to dendrimer synthesis. (United States)

    Arseneault, Mathieu; Wafer, Caroline; Morin, Jean-François


    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.

  2. Click Chemistry-Mediated Nanosensors for Biochemical Assays. (United States)

    Chen, Yiping; Xianyu, Yunlei; Wu, Jing; Yin, Binfeng; Jiang, Xingyu


    Click chemistry combined with functional nanoparticles have drawn increasing attention in biochemical assays because they are promising in developing biosensors with effective signal transformation/amplification and straightforward signal readout for clinical diagnostic assays. In this review, we focus on the latest advances of biochemical assays based on Cu (I)-catalyzed 1, 3-dipolar cycloaddition of azides and alkynes (CuAAC)-mediated nanosensors, as well as the functionalization of nanoprobes based on click chemistry. Nanoprobes including gold nanoparticles, quantum dots, magnetic nanoparticles and carbon nanomaterials are covered. We discuss the advantages of click chemistry-mediated nanosensors for biochemical assays, and give perspectives on the development of click chemistry-mediated approaches for clinical diagnosis and other biomedical applications.

  3. Recent Advances in Click Chemistry Applied to Dendrimer Synthesis

    Directory of Open Access Journals (Sweden)

    Mathieu Arseneault


    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.

  4. Seven deadly clicks essential lessons for online safety and success

    CERN Document Server

    Strupeck, Margo


    Pulling examples from high-profile pop culture cases, Seven Deadly Clicks explains the very real dangers behind common online activities, and offers advice on how to not only stay safe, but also thrive.

  5. Click Chemistry-Mediated Nanosensors for Biochemical Assays (United States)

    Chen, Yiping; Xianyu, Yunlei; Wu, Jing; Yin, Binfeng; Jiang, Xingyu


    Click chemistry combined with functional nanoparticles have drawn increasing attention in biochemical assays because they are promising in developing biosensors with effective signal transformation/amplification and straightforward signal readout for clinical diagnostic assays. In this review, we focus on the latest advances of biochemical assays based on Cu (I)-catalyzed 1, 3-dipolar cycloaddition of azides and alkynes (CuAAC)-mediated nanosensors, as well as the functionalization of nanoprobes based on click chemistry. Nanoprobes including gold nanoparticles, quantum dots, magnetic nanoparticles and carbon nanomaterials are covered. We discuss the advantages of click chemistry-mediated nanosensors for biochemical assays, and give perspectives on the development of click chemistry-mediated approaches for clinical diagnosis and other biomedical applications. PMID:27217831

  6. Dietary TAG source and level affect performance and lipase expression in larval sea bass (Dicentrarchus labrax). (United States)

    Morais, S; Cahu, C; Zambonino-Lnfante, J L; Robin, J; Rønnestad, I; Dinis, M T; Conceição, L E C


    The influence of dietary TAG source (fish oil, triolein, and coconut oil) and level (7.5 and 15% of the diet) on growth, lipase activity, and mRNA level was studied in sea bass larvae, from mouth opening until day 24 and from day 37 to 52. Fish oil and triolein induced better growth in both experiments, this being significant at a higher dietary level. Coconut oil significantly decreased growth at the higher level, possibly as the result of an excessive supply of medium-chain TAG. Growth was not related to lipase specific activity, suggesting a production in excess to dietary needs. Body lipid content was positively related to dietary lipid level and was affected by lipid quality. In addition, larval FA composition generally reflected that of the diet. The source of dietary lipid, but not the quantity, was shown to affect lipase activity significantly. Coconut oil diets induced the highest lipase activity, whereas the effect of fish oil was age dependent-it was similar to coconut oil at day 24 but induced the lowest lipase activity in 52-d-old larvae. The differential lipase response was probably caused by differences in the FA composition of the diet, related to the specificity of lipase toward FA differing in chain length and degree of saturation. No significant differences were found in lipase/glyceraldehyde-3-phosphate dehydrogenase mRNA, which suggests the existence of a posttranscriptional regulation mechanism.

  7. Modeling effectiveness of gradual increases in source level to mitigate effects of sonar on marine mammals. (United States)

    Von Benda-Beckmann, Alexander M; Wensveen, Paul J; Kvadsheim, Petter H; Lam, Frans-Peter A; Miller, Patrick J O; Tyack, Peter L; Ainslie, Michael A


    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 effectiveness of ramp-up procedures in reducing the area within which changes in hearing thresholds can occur. We modeled the level of sound killer whales (Orcinus orca) were exposed to from a generic sonar operation preceded by different ramp-up schemes. In our model, ramp-up procedures reduced the risk of killer whales receiving sounds of sufficient intensity to affect their hearing. The effectiveness of the ramp-up procedure depended strongly on the assumed response threshold and differed with ramp-up duration, although extending the duration of the ramp up beyond 5 min did not add much to its predicted mitigating effect. The main factors that limited effectiveness of ramp up in a typical antisubmarine warfare scenario were high source level, rapid moving sonar source, and long silences between consecutive sonar transmissions. Our exposure modeling approach can be used to evaluate and optimize mitigation procedures.

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

    Directory of Open Access Journals (Sweden)

    Butu, A.W.


    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.

  9. Design and synthesis of multivalent neoglycoconjugates by click conjugations

    Directory of Open Access Journals (Sweden)

    Feiqing Ding


    Full Text Available A highly stereoselective BF3∙OEt2-promoted tandem hydroamination/glycosylation on glycal scaffolds has been developed to form propargyl 3-tosylamino-2,3-dideoxysugars in a one-pot manner. Subsequent construction of multivalent 3-tosylamino-2,3-dideoxyneoglycoconjugates with potential biochemical applications was presented herein involving click conjugations as the key reaction step. The copper-catalyzed regioselective click reaction was tremendously accelerated with assistance of microwave irradiation.

  10. Using Click Chemistry to Identify Potential Drug Targets in Plasmodium (United States)


    AWARD NUMBER: W81XWH-13-1-0429 TITLE: Using "Click Chemistry" to Identify Potential Drug Targets in Plasmodium PRINCIPAL INVESTIGATOR: Dr. Purnima...SUBTITLE Sa. CONTRACT NUMBER W81XWH-1 3-1-0429 Using "Click Chemistry" to Identify Potential Drug Targets in Plasmodium 5b. GRANT NUMBER 5c. PROGRAM...Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Sporozo ite infection of the liver is the first obl igate step of the Plasmodium

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

    DEFF Research Database (Denmark)

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


    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...... active ligands including cell binding peptides are patterned in gradients by this method without losing their biological function or the conductivity of the polymer....

  12. Household Air Pollution: Sources and Exposure Levels to Fine Particulate Matter in Nairobi Slums

    Directory of Open Access Journals (Sweden)

    Kanyiva Muindi


    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.

  13. Quantitative Analysis of Cu(I) Concentration in Click Chemistry : Biotinylation at Side Chain of Propargylglycine Using Click Chemistry under Heating Conditions


    Ogasawara, Yui; Murai, Yuta; Sakihama, Yasuko; Hashidoko, Yasuyuki; Hashimoto, Makoto


    The click reaction is one of the latest techniques for the chemical modification of bioactive compounds. Chemical modifications of α-amino acid side chains are gaining significance as useful and important tools for biochemical research. Biotinylation at side chain of propargylglycine using click reaction was examined. The detail quantitative analysis of Cu(I) concentration are performed to proceed the click reaction effectively.

  14. Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter (United States)

    Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim


    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.

  15. Providing Source Code Level Portability Between CPU and GPU with MapCG

    Institute of Scientific and Technical Information of China (English)

    Chun-Tao Hong; De-Hao Chen; Yu-Bei Chen; Wen-Guang Chen; Wei-Min Zheng; Hai-Bo Lin


    Graphics processing units (GPU) have taken an important role in the general purpose computing market in recent years.At present,the common approach to programming GPU units is to write GPU specific code with low level GPU APIs such as CUDA.Although this approach can achieve good performance,it creates serious portability issues as programmers are required to write a specific version of the code for each potential target architecture.This results in high development and maintenance costs.We believe it is desirable to have a programming model which provides source code portability between CPUs and GPUs,as well as different GPUs.This would allow programmers to write one version of the code,which can be compiled and executed on either CPUs or GPUs efficiently without modification.In this paper,we propose MapCG,a MapReduce framework to provide source code level portability between CPUs and GPUs.In contrast to other approaches such as OpenCL,our framework,based on MapReduce,provides a high level programming model and makes programming much easier.We describe the design of MapCG,including the MapReduce-style high-level programming framework and the runtime system on the CPU and GPU.A prototype of the MapCG runtime,supporting multi-core CPUs and NVIDIA GPUs,was implemented. Our experimental results show that this implementation can execute the same source code efficiently on multi-core CPU platforms and GPUs,achieving an average speedup of 1.6~2.5x over previous implementations of MapReduce on eight commonly used applications.

  16. Estimating the sources of global sea level rise with data assimilation techniques (United States)

    Hay, Carling C.; Morrow, Eric; Kopp, Robert E.; Mitrovica, Jerry X.


    A rapidly melting ice sheet produces a distinctive geometry, or fingerprint, of sea level (SL) change. Thus, a network of SL observations may, in principle, be used to infer sources of meltwater flux. We outline a formalism, based on a modified Kalman smoother, for using tide gauge observations to estimate the individual sources of global SL change. We also report on a series of detection experiments based on synthetic SL data that explore the feasibility of extracting source information from SL records. The Kalman smoother technique iteratively calculates the maximum-likelihood estimate of Greenland ice sheet (GIS) and West Antarctic ice sheet (WAIS) melt at each time step, and it accommodates data gaps while also permitting the estimation of nonlinear trends. Our synthetic tests indicate that when all tide gauge records are used in the analysis, it should be possible to estimate GIS and WAIS melt rates greater than ∼0.3 and ∼0.4 mm of equivalent eustatic sea level rise per year, respectively. We have also implemented a multimodel Kalman filter that allows us to account rigorously for additional contributions to SL changes and their associated uncertainty. The multimodel filter uses 72 glacial isostatic adjustment models and 3 ocean dynamic models to estimate the most likely models for these processes given the synthetic observations. We conclude that our modified Kalman smoother procedure provides a powerful method for inferring melt rates in a warming world.

  17. Level of knowledge and sources of information about the rheumatoid arthritis in Estonian patients. (United States)

    Põlluste, Kaja; Kallikorm, Riina; Lember, Margus


    The objective of this paper was to find out how many patients with rheumatoid arthritis (RA) know about several aspects of disease, to explain the associations between the level of self-rated knowledge and patients' background and health status and to compare the importance of the main sources of information. A random sample (n = 1,259) of adult Estonian RA patients was selected from the Estonian Health Insurance Fund Database. The patients completed a self-administered questionnaire, which included information about their socio-demographic and disease characteristics, use of health services, information about the disease, and sources of information. Regression analysis was used to calculate the associations between the independent variables and level of self-rated knowledge about several aspects of RA. The results of the study indicated that the self-reported ratings of knowledge about the disease in Estonian RA patients were rather low. Health professionals were mentioned as the primary sources of information, but the longer disease history and more frequent use of health services as considerable predictors of higher ratings of knowledge refer to role of personal experience in obtaining knowledge about the disease as well.

  18. Analysis of source term modeling for low-level radioactive waste performance assessments

    Energy Technology Data Exchange (ETDEWEB)

    Icenhour, A.S.


    Site-specific radiological performance assessments are required for the disposal of low-level radioactive waste (LLW) at both commercial and US Department of Energy facilities. This work explores source term modeling of LLW disposal facilities by using two state-of-the-art computer codes, SOURCEI and SOURCE2. An overview of the performance assessment methodology is presented, and the basic processes modeled in the SOURCE1 and SOURCE2 codes are described. Comparisons are made between the two advective models for a variety of radionuclides, transport parameters, and waste-disposal technologies. These comparisons show that, in general, the zero-order model predicts undecayed cumulative fractions leached that are slightly greater than or equal to those of the first-order model. For long-lived radionuclides, results from the two models eventually reach the same value. By contrast, for short-lived radionuclides, the zero-order model predicts a slightly higher undecayed cumulative fraction leached than does the first-order model. A new methodology, based on sensitivity and uncertainty analyses, is developed for predicting intruder scenarios. This method is demonstrated for {sup 137}Cs in a tumulus-type disposal facility. The sensitivity and uncertainty analyses incorporate input-parameter uncertainty into the evaluation of a potential time of intrusion and the remaining radionuclide inventory. Finally, conclusions from this study are presented, and recommendations for continuing work are made.

  19. Human internal and external exposure to PBDEs - A review of levels and sources

    DEFF Research Database (Denmark)

    Frederiksen, Marie; Vorkamp, Katrin; Thomsen, Marianne


    This paper reviews the existing literature on human exposure to polybrominated diphenyl ethers (PBDEs), with particular focus on external exposure routes (e.g. dust, diet, and air) and the resulting internal exposure to PBDEs (e.g. breast milk and blood). Being lipophilic and persistent organic...... compounds, PBDEs accumulate in lipid-rich tissues. Consequently, food items like fish from high trophic levels or lipid-rich oils have been found to contain relatively high concentrations of PBDEs, thus presenting an important exposure pathway to humans. The presence of PBDEs in various products of everyday...... use may lead to some additional exposure in the home environment. Dust seem to be an aggregate of the indoor source, and the ingestion of dust conveys the highest intake of BDE-209 of all sources, possibly also of other PBDE congeners. The PBDE exposure through dust is significant for toddlers who...

  20. Polymer multilayer films obtained by electrochemically catalyzed click chemistry. (United States)

    Rydzek, Gaulthier; Thomann, Jean-Sébastien; Ben Ameur, Nejla; Jierry, Loïc; Mésini, Philippe; Ponche, Arnaud; Contal, Christophe; El Haitami, Alae E; Voegel, Jean-Claude; Senger, Bernard; Schaaf, Pierre; Frisch, Benoît; Boulmedais, Fouzia


    We report the covalent layer-by-layer construction of polyelectrolyte multilayer (PEM) films by using an efficient electrochemically triggered Sharpless click reaction. The click reaction is catalyzed by Cu(I) which is generated in situ from Cu(II) (originating from the dissolution of CuSO(4)) at the electrode constituting the substrate of the film. The film buildup can be controlled by the application of a mild potential inducing the reduction of Cu(II) to Cu(I) in the absence of any reducing agent or any ligand. The experiments were carried out in an electrochemical quartz crystal microbalance cell which allows both to apply a controlled potential on a gold electrode and to follow the mass deposited on the electrode through the quartz crystal microbalance. Poly(acrylic acid) (PAA) modified with either alkyne (PAA(Alk)) or azide (PAA(Az)) functions grafted onto the PAA backbone through ethylene glycol arms were used to build the PEM films. Construction takes place on gold electrodes whose potentials are more negative than a critical value, which lies between -70 and -150 mV vs Ag/AgCl (KCl sat.) reference electrode. The film thickness increment per bilayer appears independent of the applied voltage as long as it is more negative than the critical potential, but it depends upon Cu(II) and polyelectrolyte concentrations in solution and upon the reduction time of Cu(II) during each deposition step. An increase of any of these latter parameters leads to an increase of the mass deposited per layer. For given buildup conditions, the construction levels off after a given number of deposition steps which increases with the Cu(II) concentration and/or the Cu(II) reduction time. A model based on the diffusion of Cu(II) and Cu(I) ions through the film and the dynamics of the polyelectrolyte anchoring on the film, during the reduction period of Cu(II), is proposed to explain the major buildup features.

  1. Small intestine development of laying hens fed different fiber sources diets and crude protein levels

    Directory of Open Access Journals (Sweden)

    MFFM Praes


    Full Text Available The objective of the presente study was to evaluate the effects on different dietary fiber sources and crude protein levels on the intestinal morphometry of commercial layers. Isa Brown® layers with 48 weeks of age were distributed in a completely randomized experimental design with a 3 x 2 + 1 factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. At the end of the fourth experimental period (28 days each, birds were 64 weeks of age and were randomly chosen (two birds per replicate, totaling 14 birds per treatment, weighed and sacrificed by neck dislocation. Their intestine was dissected and the duodenum, jejunum and ileum were collected for subsequent analysis of intestinal morphometry. Treatments consisted of diets containing three different fiber sources (cottonseed hulls, soybean hulls or rice husks and two crude protein levels (12% or 16%. Soybean hulls and 16% crude protein level promoted, in general, an increase in villus height and crypt depth in the three intestinal segments. In the duodenum, the control diet resulted in higher villus height and crypt depth relative to the diets containing fiber. In the jejunum, higher crypt depth values. In the ileum, dietary fiber increased villus height as compared to the control diet.

  2. Low-level radioactive waste source terms for the 1992 integrated data base

    Energy Technology Data Exchange (ETDEWEB)

    Loghry, S L; Kibbey, A H; Godbee, H W; Icenhour, A S; DePaoli, S M


    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{sub 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}other{close_quotes}. Fuel cycle commercial LLW source terms are normalized on the basis of net electrical output [MW(e)-year], except for UF{sub 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. Dual mechanisms in the perceptual processing of click train temporal regularity. (United States)

    Phillips, Dennis P; Dingle, Rachel N; Hall, Susan E; Jang, Moragh


    Two experiments measured human sensitivity to temporal jitter in 25-click trains with inter-click intervals (ICIs) between 5 and 100 ms. In a naturalistic experiment using wideband clicks, jitter thresholds were a nonmonotonic function of ICI, peaking for ICIs near 40-60 ms. In a subsequent experiment, clicks were high-passed and presented against a low-frequency noise masker. Jitter threshold vs ICI functions lost the positive slope over short ICIs but retained the negative slope at long ICIs. The same behavior was seen in click rate discrimination tasks. Different processes mediate regularity analysis for click trains with ICIs above and below 40-60 ms.

  4. Click Chemistry and Radiochemistry: The First 10 Years. (United States)

    Meyer, Jan-Philip; Adumeau, Pierre; Lewis, Jason S; Zeglis, Brian M


    The advent of click chemistry has had a profound influence on almost all branches of chemical science. This is particularly true of radiochemistry and the synthesis of agents for positron emission tomography (PET), single photon emission computed tomography (SPECT), and targeted radiotherapy. The selectivity, ease, rapidity, and modularity of click ligations make them nearly ideally suited for the construction of radiotracers, a process that often involves working with biomolecules in aqueous conditions with inexorably decaying radioisotopes. In the following pages, our goal is to provide a broad overview of the first 10 years of research at the intersection of click chemistry and radiochemistry. The discussion will focus on four areas that we believe underscore the critical advantages provided by click chemistry: (i) the use of prosthetic groups for radiolabeling reactions, (ii) the creation of coordination scaffolds for radiometals, (iii) the site-specific radiolabeling of proteins and peptides, and (iv) the development of strategies for in vivo pretargeting. Particular emphasis will be placed on the four most prevalent click reactions-the Cu-catalyzed azide-alkyne cycloaddition (CuAAC), the strain-promoted azide-alkyne cycloaddition (SPAAC), the inverse electron demand Diels-Alder reaction (IEDDA), and the Staudinger ligation-although less well-known click ligations will be discussed as well. Ultimately, it is our hope that this review will not only serve to educate readers but will also act as a springboard, inspiring synthetic chemists and radiochemists alike to harness click chemistry in even more innovative and ambitious ways as we embark upon the second decade of this fruitful collaboration.

  5. Non-parametric group-level statistics for source-resolved ERP analysis. (United States)

    Lee, Clement; Miyakoshi, Makoto; Delorme, Arnaud; Cauwenberghs, Gert; Makeig, Scott


    We have developed a new statistical framework for group-level event-related potential (ERP) analysis in EEGLAB. The framework calculates the variance of scalp channel signals accounted for by the activity of homogeneous clusters of sources found by independent component analysis (ICA). When ICA data decomposition is performed on each subject's data separately, functionally equivalent ICs can be grouped into EEGLAB clusters. Here, we report a new addition (statPvaf) to the EEGLAB plug-in std_envtopo to enable inferential statistics on main effects and interactions in event related potentials (ERPs) of independent component (IC) processes at the group level. We demonstrate the use of the updated plug-in on simulated and actual EEG data.

  6. 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;


    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 accurately produce...... the correct volt-sec average at its output, while simultaneously achieving inductive voltage boosting. More interestingly, these performance features are achieved with no increase in the number of semiconductor commutations, and hence no increase in switching losses. The proposed converter therefore offers...

  7. Differential Evolution based SHEPWM for Seven-Level Inverter with Non-Equal DC Sources

    Directory of Open Access Journals (Sweden)

    Fayçal CHABNI


    Full Text Available This paper presents the application of differential evolution algorithm to obtain optimal switching angles for a single-phase seven-level to improve AC voltage quality. The proposed inverter in this article is composed of two H-bridge cells with non-equal DC voltage sources in order to generate multiple voltage levels. Selective harmonic elimination pulse width modulation (SHPWM strategy is used to improve the AC output voltage waveform generated by the proposed inverter. The differential evolution (DE optimization algorithm is used to solve non-linear transcendental equations necessary for the (SHPWM. Computational results obtained from computer simulations presented a good agreement with the theoretical predictions. A laboratory prototype based on STM32F407 microcontroller was built in order to validate the simulation results. The experimental results show the effectiveness of the proposed modulation method.

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


    [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.

  9. An integrated multi-source JDL high-level fusion architecture using recombinant cognition synthesis (United States)

    Solano, Marco A.; Ekwaro-Osire, Stephen; Tanik, Murat M.


    High-Level fusion systems based on the JDL model are relatively immature. Current solutions lack a comprehensive ability to manage multi-source data in a multi-dimensional vector space, and generally do not integrate collection to action models in a cohesive thread. Recombinant Cognition Synthesis (RCS) leverages best-of-breed techniques with a geospatial, temporal and semantic data model to provide a unified methodology that recombines multi-source data with analytic and predictive algorithms to synthesize actionable intelligence. This architecture framework enables the traversal of entity relationships at different level of granularities and the discovery of latent knowledge, thereby facilitating the domain problem analysis and the development of a Course-of-Action to mitigate adversarial threats. RCS also includes process refinement techniques to achieve superior information dominance, by incorporating specialized metadata. This comprehensive and unified methodology delivers enhanced utility to the intelligence analyst, and addresses key issues of relevancy, timeliness, accuracy, and uncertainty by providing metrics via feedback loops within the RCS infrastructure that augment the efficiency and effectiveness of the end-to-end fusion processing chain.

  10. Iodine-129 in Snow and Seawater in the Antarctic: Level and Source

    DEFF Research Database (Denmark)

    Xing, Shan; Hou, Xiaolin; Aldahan, Ala;


    , Amundsen, and Ross Seas in Antarctica in 2011 were analyzed for 129I and 127I, including organic forms; it was observed that 129I/127I atomic ratios in the Antarctic surface seawater ((6.1-13) × 10-12) are about 2 orders of magnitude lower than those in the Antarctic snow ((6.8-9.5) × 10-10), but 4-6 times......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...... higher than the prenuclear level (1.5 × 10-12), indicating a predominantly anthropogenic source of 129I in the Antarctic environment. The 129I level in snow in Antarctica is 2-4 orders of magnitude lower than that in the Northern Hemisphere, but is not significantly higher than that observed in other...

  11. Sequential and parallel dual labeling of nanoparticles using click chemistry. (United States)

    Zong, Hong; Goonewardena, Sascha N; Chang, Huai-Ning; Otis, James B; Baker, James R


    Bioorthogonal 'click' reactions have recently emerged as promising tools for chemistry and biological applications. By using a combination of two different 'click' reactions, 'double-click' strategies have been developed to attach multiple labels onto biomacromolecules. These strategies require multi-step modifications of the biomacromolecules that can lead to heterogeneity in the final conjugates. Herein, we report the synthesis and characterization of a set of three trifunctional linkers. The linkers having alkyne and cyclooctyne moieties that are capable of participating in sequential copper(I)-catalyzed and copper-free cycloaddition reactions with azides. We have also prepared a linker comprised of an alkyne and a 1,2,4,5-terazine moiety that allows for simultaneous cycloaddition reactions with azides and trans-cyclooctenes, respectively. These linkers can be attached to synthetic or biological macromolecules to create a platform capable of sequential or parallel 'double-click' labeling in biological systems. We show this potential using a generation 5 (G5) polyamidoamine (PAMAM) dendrimer in combination with the clickable linkers. The dendrimers were successfully modified with these linkers and we demonstrate both sequential and parallel 'double-click' labeling with fluorescent reporters. We anticipate that these linkers will have a variety of application including molecular imaging and monitoring of macromolecule interactions in biological systems.

  12. Influence of lanthanum level and interactions with nitrogen source on early development of Juglans nigra

    Institute of Scientific and Technical Information of China (English)

    Nicodemus; Michael A; Salifu; K Francis; Jacobs; Douglass F


    Rare earth elements have been used for 30 years in Chinese agriculture to improve growth and yield. Numerous scientific studies have shown improvements in physiology, mineral nutrition, and growth, though deleterious effects may also occur. Very few studies have been performed on woody species. We exponentially fertilized one-year old black walnut (Juglans nigra L.) seedlings with 0, 0.1, 1, 10, or 100 mg lanthanum (La) and 800 mg nitrogen (N) as NaNO3, (NH4)2SO4, NH4NO3, or no N. One month following final fertilization, growth, mineral nutrition, photosynthesis, chlorophyll, and nitrate reductase activity were assessed. Plants fertilized with the highest level of La had reduced fine root growth, concentrations of magnesium, calcium, nickel, and phosphorus, photosynthesis levels, and chlorophyll a content. Foliar La concentration showed an interaction effect, with three to four times greater concentration in plants fed at 100 mg La to those given 10 mg La for (NH4)2SO4 and NH4NO3 treatments. The results suggested no beneficial effects of La addition at levels used in this study and interactions between N source and La levels did not have an important impact on the growth, mineral nutrition, or physiology of black walnut seedlings.

  13. Cooperative capture synthesis: yet another playground for copper-free click chemistry. (United States)

    Hou, Xisen; Ke, Chenfeng; Fraser Stoddart, J


    Click chemistry describes a family of modular, efficient, versatile and reliable reactions which have acquired a pivotal role as one of the most useful synthetic tools with a potentially broad range of applications. While copper(i)-catalysed alkyne-azide cycloaddition is the most widely adopted click reaction in the family, the fact that it is cytotoxic restricts its practice in certain situations, e.g., bioconjugation. Consequently, researchers have been exploring the development of copper-free click reactions, the most popular example so far being strain-promoted alkyne-azide cycloadditions. An early example of copper-free click reactions that is rarely mentioned in the literature is the cucurbit[6]uril (CB6) catalysed alkyne-azide cycloaddition (CB-AAC). Despite the unique ability of CB-AAC to generate mechanically interlocked molecules (MIMs) - in particular, rotaxanes - its slow reaction rate and narrow substrate acceptance limit its scope. In this Tutorial Review, we describe our efforts of late in developing the fundamental principles and practical applications of a new copper-free click reaction - namely, cooperative capture synthesis, whereby introducing a cyclodextrin (CD) as an accelerator in CB-AAC, hydrogen bonding networks are formed between the rims of CD and CB6 in a manner that is positively cooperative, giving rise to a high level of pre-organisation during efficient and quick rotaxane formation. For example, [4]rotaxanes can be prepared nearly quantitatively within a minute in water. Furthermore, we have demonstrated that CB-AAC can accommodate a wider substrate tolerance by introducing pillararenes as promoters. To date, we have put cooperative capture synthesis into practice by (i) preparing polyrotaxanes containing up to 200 rings in nearly quantitative yields, (ii) trapping conformational isomers of polymacrocycles as rings in rotaxanes, (iii) demonstrating solid-state fluorescence and Förster resonance energy transfer (FRET) processes by


    Directory of Open Access Journals (Sweden)



    Full Text Available This study was conducted to investigate the effect of replacement of 50% cottonseed meal (CSM nitrogen with various non protein nitrogen (NPN sources i.e. urea (CU, biuret (CB and diammonium phosphate (CD. The four energy sources were: wheat straw with no corn starch (WS, WS + 20% corn starch, WS + 30% corn starch and WS + 40% corn starch. These substrates were fermented with rumen liquor to measure in vitro dry matter digestibility (DMD, bacterial count and ammonia nitrogen (NH3-N concentrations. The protein sources provided 2% nitrogen (12.5% CP. The control substrate contained CSM as the sole source of nitrogen and ground wheat straw as the sole sources of energy. The in vitro DMD increased to 49.10, 40.06 and 31.52% in substrates containing CB, CU and CD compared to 23.10% for CSM (P<0.01. Similarly, supplementation of straw with 20, 30 and 40% corn starch gave 24.31, 38.03 and 45.48% DMD compared to 23.10% for control (P<0.01. Increase of corn starch from 20 to 30% resulted in 13.72 units higher DMD which increased to a mere 7.45 units when the corn starch was raised from 30 to 40%. The interactions between nitrogen sources and starch levels revealed that substrate CB x 40% corn starch yielded 70.73% DMD, followed by 49.66% DMD with CU x 40% starch (P<0.01. The NH3-N increased due to 50% replacement of CSM with NPN sources on isonitrogenous basis. It was maximum with CU as nitrogen source, followed by CD, CB and CSM. The differences among the four nitrogen sources were significant (P<0.01. The substrates containing CU resulted in highest bacterial counts of 33.78x108 compared to 20.41x108, 17.06x108 and 11.34x108 for CB, CSM and CD, respectively (P<0.01. Addition of corn starch up to 20 and 30% to straw based substrates increased the bacterial counts to 23.25x108 and 23.12x108 and 40% corn starch yielded 15.58x108 bacterial counts which was significantly (P<0.01 lesser than 17.06x108 for substrates containing 0% corn starch. Bacterial count

  15. DC Bus Control of Back-to-Back Connected Two-Level PWM Rectifier-Five-Level NPC Voltage Source Inverter to Torque Ripple Reduction in Induction Motor

    Directory of Open Access Journals (Sweden)

    Abdelkrim Thameur


    Full Text Available This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.

  16. Short first click intervals in echolocation trains of three species of deep diving odontocetes. (United States)

    Dunn, Charlotte A; Tyack, Peter; Miller, Patrick J O; Rendell, Luke


    All odontocetes produce echolocation clicks as part of their vocal repertoire. In this paper the authors analysed inter-click-intervals in recordings from suction cup tags with a focus on the first inter-click interval of each click train. The authors refer to shorter first inter-click intervals as short first intervals (SFIs). The authors found that the context of SFI occurrence varies across three deep-diving species. In Blainville's beaked whales, 87% of click trains that were preceded by a terminal buzz started with SFIs. In Cuvier's beaked whales, only sub-adult animals produced notable amounts of SFIs. In contrast, sperm whales were much more likely to produce SFIs on the first click train of a dive. While the physiological and/or behavioural reasons for SFI click production are unknown, species differences in their production could provide a window into the evolution of odontocete echolocation.

  17. Preparation of Lanthanide-Polymer Composite Material via Click Chemistry. (United States)

    Chen, Bin; Wen, Guian; Wu, Jiajie; Feng, Jiachun


    Covalently attaching lanthanide complexes to the polymer backbone can effectively reduce the clustering of lanthanides and thus become an important strategy to fully unleash their potential. In this Communication, a metal-free click reaction is used for the first time to link a lanthanide complex to the polymer matrix. A diene-bearing copolymer with anthracenylmethyl methacrylate as a monomer and a dienophile-bearing lanthanide complex with 5-maleimido-1,10-phenanthroline as the second ligand are synthesized and coupled together through a Diels-Alder cycloaddition (DA). A comparative investigation demonstrates that the composite material prepared by DA click reaction shows the highest quantum yields in the same lanthanide concentration as compared to materials prepared by widely used "directly doping" and "in situ coordinating lanthanide ions with macromolecular ligand" approaches. This work suggests that the "metal-free" DA click reaction can be a promising tool in the synthesis of high efficient lanthanide functionalized polymeric materials.

  18. Click-EM for imaging metabolically tagged nonprotein biomolecules. (United States)

    Ngo, John T; Adams, Stephen R; Deerinck, Thomas J; Boassa, Daniela; Rodriguez-Rivera, Frances; Palida, Sakina F; Bertozzi, Carolyn R; Ellisman, Mark H; Tsien, Roger Y


    EM has long been the main technique for imaging cell structures with nanometer resolution but has lagged behind light microscopy in the crucial ability to make specific molecules stand out. Here we introduce click-EM, a labeling technique for correlative light microscopy and EM imaging of nonprotein biomolecules. In this approach, metabolic labeling substrates containing bioorthogonal functional groups are provided to cells for incorporation into biopolymers by endogenous biosynthetic machinery. The unique chemical functionality of these analogs is exploited for selective attachment of singlet oxygen-generating fluorescent dyes via bioorthogonal 'click chemistry' ligations. Illumination of dye-labeled structures generates singlet oxygen to locally catalyze the polymerization of diaminobenzidine into an osmiophilic reaction product that is readily imaged by EM. We describe the application of click-EM in imaging metabolically tagged DNA, RNA and lipids in cultured cells and neurons and highlight its use in tracking peptidoglycan synthesis in the Gram-positive bacterium Listeria monocytogenes.

  19. Fluorescence imaging of chromosomal DNA using click chemistry (United States)

    Ishizuka, Takumi; Liu, Hong Shan; Ito, Kenichiro; Xu, Yan


    Chromosome visualization is essential for chromosome analysis and genetic diagnostics. Here, we developed a click chemistry approach for multicolor imaging of chromosomal DNA instead of the traditional dye method. We first demonstrated that the commercially available reagents allow for the multicolor staining of chromosomes. We then prepared two pro-fluorophore moieties that served as light-up reporters to stain chromosomal DNA based on click reaction and visualized the clear chromosomes in multicolor. We applied this strategy in fluorescence in situ hybridization (FISH) and identified, with high sensitivity and specificity, telomere DNA at the end of the chromosome. We further extended this approach to observe several basic stages of cell division. We found that the click reaction enables direct visualization of the chromosome behavior in cell division. These results suggest that the technique can be broadly used for imaging chromosomes and may serve as a new approach for chromosome analysis and genetic diagnostics.

  20. Fluorescence imaging of chromosomal DNA using click chemistry (United States)

    Ishizuka, Takumi; Liu, Hong Shan; Ito, Kenichiro; Xu, Yan


    Chromosome visualization is essential for chromosome analysis and genetic diagnostics. Here, we developed a click chemistry approach for multicolor imaging of chromosomal DNA instead of the traditional dye method. We first demonstrated that the commercially available reagents allow for the multicolor staining of chromosomes. We then prepared two pro-fluorophore moieties that served as light-up reporters to stain chromosomal DNA based on click reaction and visualized the clear chromosomes in multicolor. We applied this strategy in fluorescence in situ hybridization (FISH) and identified, with high sensitivity and specificity, telomere DNA at the end of the chromosome. We further extended this approach to observe several basic stages of cell division. We found that the click reaction enables direct visualization of the chromosome behavior in cell division. These results suggest that the technique can be broadly used for imaging chromosomes and may serve as a new approach for chromosome analysis and genetic diagnostics. PMID:27620982

  1. Click-iT assay with improved DNA distribution histograms. (United States)

    Hamelik, Ronald M; Krishan, Awtar


    The Click-iT Assay developed and commercialized by Invitrogen is based on incorporation of a new 5-bromo-2'-deoxyuridine analog, 5-ethynyl-2'-deoxyuridine (EdU) into newly synthesized DNA and its recognition by azide dyes via a copper mediated "click" reaction. This relatively convenient and useful procedure depends on fixation of cells with paraformaldehyde and staining of the DNA with 7-aminoactinomycin-D (7-AAD). Both of these procedures result in DNA histograms with broad coefficients of variation (CV's). In this report, we have shown that after EdU incorporation, nuclei isolated by lysis can be incubated with the Click-iT Assay and stained with propidium iodide for generation of DNA histograms with low CV's. This modified procedure results in better DNA histograms by replacing 7-AAD with propidium iodide and also saves processing time by eliminating the fixation and permeabilization steps.

  2. Impacts of natural emission sources on particle pollution levels in Europe (United States)

    Liora, Natalia; Poupkou, Anastasia; Giannaros, Theodore M.; Kakosimos, Konstantinos E.; Stein, Olaf; Melas, Dimitrios


    The main objective of this work is the study of the impact of windblown dust, sea-salt aerosol and biogenic emissions on particle pollution levels in Europe. The Natural Emissions MOdel (NEMO) and the modelling system consisted of the Weather Research and Forecasting model (WRF) and the Comprehensive Air Quality model with extensions (CAMx) were applied in a 30 km horizontal resolution grid, which covered Europe and the adjacent areas for the year 2009. Air quality simulations were performed for different emission scenarios in order to study the contribution of each natural emission source individually and together to air quality levels in Europe. The simulations reveal that the exclusion of windblown dust emissions decreases the mean seasonal PM10 levels by more than 3.3 μg/m3 (∼20%) in the Eastern Mediterranean during winter while an impact of 3 μg/m3 was also found during summer. The results suggest that sea-salt aerosol has a significant effect on PM levels and composition. Eliminating sea-salt emissions reduces PM10 seasonal concentrations by around 10 μg/m3 in Mediterranean Sea during summer while a decrease of up to 6 μg/m3 is found in Atlantic Ocean during autumn. Sea-salt particles also interact with the anthropogenic component and therefore their absence in the atmosphere decreases significantly the nitrates in aerosols where shipping activities are present. The exclusion of biogenic emissions in the model runs leads to a significant reduction of secondary organic aerosols of more than 90% while an increase in PM2.5 levels in central Europe and Eastern Mediterranean is found due to their interaction with anthropogenic component.

  3. Selective harmonic elimination strategy in eleven level inverter for PV system with unbalanced DC sources (United States)

    Ghoudelbourk, Sihem.; Dib, D.; Meghni, B.; Zouli, M.


    The paper deals with the multilevel converters control strategy for photovoltaic system integrated in distribution grids. The objective of the proposed work is to design multilevel inverters for solar energy applications so as to reduce the Total Harmonic Distortion (THD) and to improve the power quality. The multilevel inverter power structure plays a vital role in every aspect of the power system. It is easier to produce a high-power, high-voltage inverter with the multilevel structure. The topologies of multilevel inverter have several advantages such as high output voltage, lower total harmonic distortion (THD) and reduction of voltage ratings of the power semiconductor switching devices. The proposed control strategy ensures an implementation of selective harmonic elimination (SHE) modulation for eleven levels. SHE is a very important and efficient strategy of eliminating selected harmonics by judicious selection of the firing angles of the inverter. Harmonics elimination technique eliminates the need of the expensive low pass filters in the system. Previous research considered that constant and equal DC sources with invariant behavior; however, this research extends earlier work to include variant DC sources, which are typical of lead-acid batteries when used in system PV. This Study also investigates methods to minimize the total harmonic distortion of the synthesized multilevel waveform and to help balance the battery voltage. The harmonic elimination method was used to eliminate selected lower dominant harmonics resulting from the inverter switching action.

  4. Level, potential sources of polycyclic aromatic hydrocarbons (PAHs) in particulate matter (PM10) in Naples (United States)

    Di Vaio, Paola; Cocozziello, Beatrice; Corvino, Angela; Fiorino, Ferdinando; Frecentese, Francesco; Magli, Elisa; Onorati, Giuseppe; Saccone, Irene; Santagada, Vincenzo; Settimo, Gaetano; Severino, Beatrice; Perissutti, Elisa


    In Naples, particulate matter PM10 associated with polycyclic aromatic hydrocarbons (PAHs) in ambient air were determined in urban background (NA01) and urban traffic (NA02) sites. The principal objective of the study was to determine the concentration and distribution of PAHs in PM10 for identification of their possible sources (through diagnostic ratio - DR and principal component analysis - PCA) and an estimation of the human health risk (from exposure to airborne TEQ). Airborne PM10 samples were collected on quartz filters using a Low Volume Sampler (LVS) for 24 h with seasonal samples (autumn, winter, spring and summer) of about 15 days each between October 2012 and July 2013. The PM10 mass was gravimetrically determined. The PM10 levels, in all seasons, were significantly higher (P natural gas emissions. In particular diesel vehicular emissions were the major source of PAHs at the studied sites. The use of Toxicity Equivalence Quantity (TEQ) concentration provide a better estimation of carcinogenicity activities; health risk to adults and children associated with PAHs inhalation was assessed by taking into account the lifetime average daily dose and corresponding incremental lifetime cancer risk (ILCR). The ILCR was within the acceptable range (10-6-10-4), indicating a low health risk to residents in these areas.

  5. 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:; 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)


    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.

  6. Low-Level RF Control of Spallation Neutron Source: System and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hengjie [ORNL


    The low-level RF control system currently commissioned throughout the Spallation Neutron Source (SNS) LINAC evolved from three design iterations over one year 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 co-simulation 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.

  7. Whistle source levels of free-ranging beluga whales in Saguenay-St. Lawrence marine park. (United States)

    Le Bot, Olivier; Simard, Yvan; Roy, Nathalie; Mars, Jérôme I; Gervaise, Cédric


    Wild beluga whistle source levels (SLs) are estimated from 52 three-dimensional (3D) localized calls using a 4-hydrophone array. The probability distribution functions of the root-mean-square (rms) SL in the time domain, and the peak, the strongest 3-dB, and 10-dB SLs from the spectrogram, were non-Gaussian. The average rms SL was 143.8 ± 6.7 dB re 1 μPa at 1 m. SL spectral metrics were, respectively, 145.8 ± 8 dB, 143.2 ± 7.1 dB, and 138.5 ± 6.9 dB re 1 μPa(2)·Hz(-1) at 1 m.

  8. 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;


    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...... parameters to evaluate converter parameters for any application. The equations obtained were confirmed by simulation and experimental setup. Field of application has been discussed....

  9. Sea Level and Paleoenvironment Control on Late Ordovician Source Rocks, Hudson Bay Basin, Canada (United States)

    Zhang, S.; Hefter, J.


    Hudson Bay Basin is one of the largest Paleozoic sedimentary basins in North America, with Southampton Island on its north margin. The lower part of the basin succession comprises approximately 180 to 300 m of Upper Ordovician strata including Bad Cache Rapids and Churchill River groups and Red Head Rapids Formation. These units mainly comprise carbonate rocks consisting of alternating fossiliferous limestone, evaporitic and reefal dolostone, and minor shale. Shale units containing extremely high TOC, and interpreted to have potential as petroleum source rocks, were found at three levels in the lower Red Head Rapids Formation on Southampton Island, and were also recognized in exploration wells from the Hudson Bay offshore area. A study of conodonts from 390 conodont-bearing samples from continuous cores and well cuttings from six exploration wells in the Hudson Bay Lowlands and offshore area (Comeault Province No. 1, Kaskattama Province No. 1, Pen Island No. 1, Walrus A-71, Polar Bear C-11 and Narwhal South O-58), and about 250 conodont-bearing samples collected from outcrops on Southampton Island allows recognition of three conodont zones in the Upper Ordovician sequence, namely (in ascendant sequence) Belodina confluens, Amorphognathus ordovicicus, and Rhipidognathus symmetricus zones. The three conodont zones suggest a cycle of sea level changes of rising, reaching the highest level, and then falling during the Late Ordovician. Three intervals of petroleum potential source rock are within the Rhipidognathus symmetricus Zone in Red Head Rapids Formation, and formed in a restricted anoxic and hypersaline condition during a period of sea level falling. This is supported by the following data: 1) The conodont Rhipidognathus symmetricus represents the shallowest Late Ordovician conodont biofacies and very shallow subtidal to intertidal and hypersaline condition. This species has the greatest richness within the three oil shale intervals to compare other parts of Red

  10. Assessing Acoustic Sound Levels Associated with Active Source Seismic Surveys in Shallow Marine Environments (United States)

    Bohnenstiehl, D. R.; Tolstoy, M.; Thode, A.; Diebold, J. B.; Webb, S. C.


    The potential effect of active source seismic research on marine mammal populations is a topic of increasing concern, and controversy surrounding such operations has begun to impact the planning and permitting of academic surveys [e.g., Malakoff, 2002 Science]. Although no causal relationship between marine mammal strandings and seismic exploration has been proven, any circumstantial evidence must be thoroughly investigated. A 2002 stranding of two beaked whales in the Gulf of California within 50 km of a R/V Ewing seismic survey has been a subject of concern for both marine seismologists and environmentalists. In order to better understand possible received levels for whales in the vicinity of these operations, modeling is combined with ground-truth calibration measurements. A wide-angle parabolic equation model, which is capable of including shear within the sediment and basement layers, is used to generate predictive models of low-frequency transmission loss within the Gulf of California. This work incorporates range-dependent bathymetry, sediment thickness, sound velocity structure and sub-bottom properties. Oceanic sounds speed profiles are derived from the U.S. Navy's seasonal GDEM model and sediment thicknesses are taken from NOAA's worldwide database. The spectral content of the Ewing's 20-airgun seismic array is constrained by field calibration in the spring of 2003 [Tolstoy et al., 2004 GRL], indicating peak energies at frequencies below a few hundred Hz, with energy spectral density showing an approximate power-law decrease at higher frequencies (being ~40 dB below peak at 1 kHz). Transmission loss is estimated along a series of radials extending from multiple positions along the ship's track, with the directivity of the array accounted for by phase-shifting point sources that are scaled by the cube root of the individual airgun volumes. This allows the time-space history of low-frequency received levels to be reconstructed within the Gulf of California

  11. TIDE TOOL: Open-Source Sea-Level Monitoring Software for Tsunami Warning Systems (United States)

    Weinstein, S. A.; Kong, L. S.; Becker, N. C.; Wang, D.


    A tsunami warning center (TWC) typically decides to issue a tsunami warning bulletin when initial estimates of earthquake source parameters suggest it may be capable of generating a tsunami. A TWC, however, relies on sea-level data to provide prima facie evidence for the existence or non-existence of destructive tsunami waves and to constrain tsunami wave height forecast models. In the aftermath of the 2004 Sumatra disaster, the International Tsunami Information Center asked the Pacific Tsunami Warning Center (PTWC) to develop a platform-independent, easy-to-use software package to give nascent TWCs the ability to process WMO Global Telecommunications System (GTS) sea-level messages and to analyze the resulting sea-level curves (marigrams). In response PTWC developed TIDE TOOL that has since steadily grown in sophistication to become PTWC's operational sea-level processing system. TIDE TOOL has two main parts: a decoder that reads GTS sea-level message logs, and a graphical user interface (GUI) written in the open-source platform-independent graphical toolkit scripting language Tcl/Tk. This GUI consists of dynamic map-based clients that allow the user to select and analyze a single station or groups of stations by displaying their marigams in strip-chart or screen-tiled forms. TIDE TOOL also includes detail maps of each station to show each station's geographical context and reverse tsunami travel time contours to each station. TIDE TOOL can also be coupled to the GEOWARE™ TTT program to plot tsunami travel times and to indicate the expected tsunami arrival time on the marigrams. Because sea-level messages are structured in a rich variety of formats TIDE TOOL includes a metadata file, COMP_META, that contains all of the information needed by TIDE TOOL to decode sea-level data as well as basic information such as the geographical coordinates of each station. TIDE TOOL can therefore continuously decode theses sea-level messages in real-time and display the time

  12. sources

    Directory of Open Access Journals (Sweden)

    Shu-Yin Chiang


    Full Text Available In this paper, we study the simplified models of the ATM (Asynchronous Transfer Mode multiplexer network with Bernoulli random traffic sources. Based on the model, the performance measures are analyzed by the different output service schemes.

  13. 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.


    Directory of Open Access Journals (Sweden)

    M.Yu. Sychov


    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

  15. Southern Dobrogea coastal potable water sources and Upper Quaternary Black Sea level changes (United States)

    Caraivan, Glicherie; Stefanescu, Diana


    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

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

    DEFF Research Database (Denmark)

    Beedholm, Kristian


    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...

  17. Evaluating intuitiveness of vertical-aware click models

    NARCIS (Netherlands)

    Chuklin, A.; Zhou, K.; Schuth, A.; Sietsma, F.; de Rijke, M.


    Modeling user behavior on a search engine result page is important for understanding the users and supporting simulation experiments. As result pages become more complex, click models evolve as well in order to capture additional aspects of user behavior in response to new forms of result presentati

  18. Coupling of Ligands to the Liposome Surface by Click Chemistry. (United States)

    Spanedda, Maria Vittoria; De Giorgi, Marcella; Hassane, Fatouma Saïd; Schuber, Francis; Bourel-Bonnet, Line; Frisch, Benoît


    Click chemistry represents a new bioconjugation strategy that can be used to conveniently attach various ligands to the surface of preformed liposomes. This efficient and chemoselective reaction involves a Cu(I)-catalyzed azide-alkyne cycloaddition which can be performed under mild experimental conditions in aqueous media. Here we describe the application of a model click reaction to the conjugation, in a single step, of unprotected α-1-thiomannosyl ligands, functionalized with an azide group, to liposomes containing a terminal alkyne-functionalized lipid anchor. Excellent coupling yields have been obtained in the presence of bathophenanthroline disulfonate, a water soluble copper-ion chelator, acting as a catalyst. No vesicle leakage is triggered by this conjugation reaction and the coupled mannose ligands are exposed at the surface of the liposomes. The major limitation of Cu(I)-catalyzed click reactions is that this conjugation is restricted to liposomes made of saturated (phospho)lipids. To circumvent that constraint, an example of alternative copper-free azide-alkyne click reaction has been developed. Molecular tools and results are presented here.

  19. Decoration of silk fibroin by click chemistry for biomedical application. (United States)

    Zhao, Hongshi; Heusler, Eva; Jones, Gabriel; Li, Linhao; Werner, Vera; Germershaus, Oliver; Ritzer, Jennifer; Luehmann, Tessa; Meinel, Lorenz


    Silkfibroin (SF) has an excellent biocompatibility and its remarkable structure translates into exciting mechanical properties rendering this biomaterial particularly fascinating for biomedical application. To further boost the material's biological/preclinical impact, SF is decorated with biologics, typically by carbodiimide/N-hydroxysuccinimide coupling (EDC/NHS). For biomedical application, this chemistry challenges the product risk profile due to the formation of covalent aggregates, particularly when decoration is with biologics occurring naturally in humans as these aggregates may prime for autoimmunity. Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC; click chemistry) provides the necessary specificity to avoid such intermolecular, covalent aggregates. We present a blueprint outlining the necessary chemistry rendering SF compatible with CuAAC and with a particular focus on structural consequences. For that, the number of SF carboxyl groups (carboxyl-SF; required for EDC/NHS chemistry) or azido groups (azido-SF; required for click chemistry) was tailored by means of diazonium coupling of the SF tyrosine residues. Structural impact on SF and decorated SF was characterized by Fourier transform infrared spectroscopy (FTIR). The click chemistry yielded a better controlled product as compared to the EDC/NHS chemistry with no formation of inter- and intramolecular crosslinks as demonstrated for SF decorated with fluorescent model compounds or a biologic, fibroblast growth factor 2 (FGF2), respectively. In conclusion, SF can readily be translated into a scaffold compatible with click chemistry yielding decorated products with a better risk profile for biomedical application.

  20. Click-based synthesis and proteomic profiling of lipstatin analogues


    Ngai, Mun H.; Yang, Peng-Yu; Liu, Kai; Shen, Yuan; Wenk, Markus R; Yao, Shao Q.; Lear, Martin J.


    Using click chemistry to enable both structural diversity and proteome profiling within a natural product derived library, two out of nineteen lipstatin analogues showed similar activity to Orlistat against fatty acid synthase (FAS), but with an improved ability to induce tumour cell death.

  1. Synthesis of Phenyl-Adducted Cyclodextrin through the Click Reaction (United States)

    A new derivative of ß-cyclodextrin (CD) has been made incorporating the phenyl group through the use of click reaction. The resulting product exhibits a self-association phenomenon through the formation of inclusion compound between the phenyl group and CD. The product has been characterized by 1H...

  2. Phonetic reduction of clicks – Evidence from Nǀuu

    DEFF Research Database (Denmark)

    Marquard, Carina; Niebuhr, Oliver; Witzlack-Makarevich, Alena


    Based on spontaneous speech data of the Tuu language Nǀuu, we used the cross-linguistically established domain-initial strengthening concept in order to examine, if and in which way clicks are subject to speech reduction (lenition) in relation to a reference sample of plosives. Results of combined...

  3. Building a Better Clicks-and-Mortar Library (United States)

    Vesey, Ken


    One of the most important roles for school libraries in the digital age is to provide students with a context for processing Internet information. It has been suggested that the school library should strive for a more pronounced clicks-and-mortar identity combining the best of the web and the traditional library collection.

  4. DNA barcoding of Japanese click beetles (Coleoptera, Elateridae). (United States)

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


    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.

  5. Modular 'click-in-emulsion' bone-targeted nanogels. (United States)

    Heller, Daniel A; Levi, Yair; Pelet, Jeisa M; Doloff, Joshua C; Wallas, Jasmine; Pratt, George W; Jiang, Shan; Sahay, Gaurav; Schroeder, Avi; Schroeder, Josh E; Chyan, Yieu; Zurenko, Christopher; Querbes, William; Manzano, Miguel; Kohane, Daniel S; Langer, Robert; Anderson, Daniel G


    A new class of nanogel demonstrates modular biodistribution and affinity for bone. Nanogels, ∼70 nm in diameter and synthesized via an astoichiometric click-chemistry in-emulsion method, controllably display residual, free clickable functional groups. Functionalization with a bisphosphonate ligand results in significant binding to bone on the inner walls of marrow cavities, liver avoidance, and anti-osteoporotic effects.

  6. Modular ‘Click-in-Emulsion’ Bone-Targeted Nanogels



    A new class of nanogel demonstrates modular biodistribution and affinity for bone. Nanogels, ~70 nm in diameter and synthesized via an astoichiometric click-chemistry in-emulsion method, controllably display residual, free clickable functional groups. Functionalization with a bisphosphonate ligand results in significant binding to bone on the inner walls of marrow cavities, liver avoidance, and anti-osteoporotic effects.

  7. Flipping & Clicking Your Way to Higher-Order Learning (United States)

    Garver, Michael S.; Roberts, Brian A.


    This innovative system of teaching and learning includes the implementation of two effective learning technologies: podcasting ("flipping") and classroom response systems ("clicking"). Students watch lectures in podcast format before coming to class, which allows the "entire" class period to be devoted to active…

  8. Functionalization of Mechanochemically Passivated Germanium Nanoparticles via "Click" Chemistry (United States)

    Purkait, Tapas Kumar

    Germanium nanoparticles (Ge NPs) may be fascinating for their electronic and optoelectronic properties, as the band gap of Ge NPs can be tuned from the infrared into the visible range of solar spectru. Further functionalization of those nanoparticles may potentially lead to numerous applications ranging from surface attachment, bioimaging, drug delivery and nanoparticles based devices. Blue luminescent germanium nanoparticles were synthesized from a novel top-down mechanochemical process using high energy ball milling (HEBM) of bulk germanium. Various reactive organic molecules (such as, alkynes, nitriles, azides) were used in this process to react with fresh surface and passivate the surface through Ge-C or Ge-N bond. Various purification process, such as gel permeation chromatography (GPC), Soxhlet dailysis etc. were introduced to purify nanoparticles from molecular impurities. A size separation technique was developed using GPC. The size separated Ge NPs were characterize by TEM, small angle X-ray scattering (SAXS), UV-vis absorption and photoluminescence (PL) emission spectroscopy to investigate their size selective properties. Germanium nanoparticles with alkyne termini group were prepared by HEBM of germanium with a mixture of n-alkynes and alpha, o-diynes. Additional functionalization of those nanoparticles was achieved by copper(I) catalyzed azide-alkyne "click" reaction. A variety of organic and organometallic azides including biologically important glucals have been reacted in this manner resulting in nanopartilces adorned with ferrocenyl, trimethylsilyl, and glucal groups. Additional functionalization of those nanoparticles was achieved by reactions with various azides via a Cu(I) catalyzed azide-alkyne "click" reaction. Various azides, including PEG derivatives and cylcodextrin moiety, were grafted to the initially formed surface. Globular nanoparticle arrays were formed through interparticle linking via "click" chemistry or "host-guest" chemistry

  9. Peripartum responses of dairy cows to prepartal feeding level and dietary fatty acid source. (United States)

    Hayirli, A; Keisler, D H; Doepel, L; Petit, Hélène


    This experiment was conducted to investigate the effect of feeding level and oilseed supplementation during the close-up dry period on energy balance (EB), hepatic lipidosis, metabolic status, and productivity in early lactation. Seventy-seven Holstein cows were blocked according to parity and expected calving date and then assigned randomly to 1 of 6 treatments in a 2 × 3 factorial allocation with 2 feeding levels: ad libitum (AL) or 30% feed restriction (FR), and 3 dietary fatty acid sources: canola seed, linola seed, or flaxseed at 8% of dietary dry matter (DM), to enrich the rations with oleic, linoleic, or linolenic acids, respectively during the last 4 wk of gestation. After parturition, all cows were fed a common lactation diet. Cows fed AL lost less body weight (-2.9 vs. -6.0%) and body condition score (+0.67 vs. -2.30%), and consequently were in more positive EB (+4.6 vs. -0.3 Mcal) during the prepartum period than cows subjected to FR. Postpartum, FR cows lost less body weight (-9.7 vs. -12.4%) and experienced less severe negative EB (-4.5 vs. -7.0 Mcal) than AL cows. Cows fed AL had higher plasma insulin (6.8 vs. 4.4 μIU/mL) and lower nonesterified fatty acid concentrations (436 vs. 570 mEq/mL) during the close-up period than cows subjected to FR. Cows fed AL tended to have lower liver glycogen content in early lactation than cows subjected to FR (4.4 vs. 2.9 % of DM) [corrected], but had similar triglyceride content (13.1 ± 1.2 μg/g of DM). Fatty acid source did not influence response variables. In conclusion, eliminating intake depression by FR during the close-up period had positive carryover effects on EB and metabolic status during early lactation, but feeding linoleic and linolenic acids via unprotected oilseeds only had negligible effects on peripartum responses.

  10. Polychlorinated Biphenyl Sources, Emissions, and Environmental Levels in school Buildings (PCB Workshop presentation) (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...

  11. Starch source influences dietary glucose generation at the mucosal α-glucosidase level. (United States)

    Lin, Amy Hui-Mei; Lee, Byung-Hoo; Nichols, Buford L; Quezada-Calvillo, Roberto; Rose, David R; Naim, Hassan Y; Hamaker, Bruce R


    The quality of starch digestion, related to the rate and extent of release of dietary glucose, is associated with glycemia-related problems such as diabetes and other metabolic syndrome conditions. Here, we found that the rate of glucose generation from starch is unexpectedly associated with mucosal α-glucosidases and not just α-amylase. This understanding could lead to a new approach to regulate the glycemic response and glucose-related physiologic responses in the human body. There are six digestive enzymes for starch: salivary and pancreatic α-amylases and four mucosal α-glucosidases, including N- and C-terminal subunits of both maltase-glucoamylase and sucrase-isomaltase. Only the mucosal α-glucosidases provide the final hydrolytic activities to produce substantial free glucose. We report here the unique and shared roles of the individual α-glucosidases for α-glucans persisting after starch is extensively hydrolyzed by α-amylase (to produce α-limit dextrins (α-LDx)). All four α-glucosidases share digestion of linear regions of α-LDx, and three can hydrolyze branched fractions. The α-LDx, which were derived from different maize cultivars, were not all equally digested, revealing that the starch source influences glucose generation at the mucosal α-glucosidase level. We further discovered a fraction of α-LDx that was resistant to the extensive digestion by the mucosal α-glucosidases. Our study further challenges the conventional view that α-amylase is the only rate-determining enzyme involved in starch digestion and better defines the roles of individual and collective mucosal α-glucosidases. Strategies to control the rate of glucogenesis at the mucosal level could lead to regulation of the glycemic response and improved glucose management in the human body.

  12. Improved thermal-vacuum compatible flat plate radiometric source for system-level testing of remote optical sensors (United States)

    Schwarz, Mark A.; Kent, Craig J.; Bousquet, Robert; Brown, Steven W.


    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. Keywords: Calibration, radiometry, remote sensing, source.

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

    KAUST Repository

    Lundberg, Erik P.


    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.

  14. DNA Stratigraphy reveals Holocene Haptophyte Population Dynamics and Sources of Alkenones at the Species Level (United States)

    Coolen, M. J. L.


    Lipid biomarkers provide information on the ancient microbiota of aquatic systems and, hence, can be used to reconstruct the palaeoenvironment. However, these biomarkers are often not very specific. The ultimate biomarkers would be ribosomal RNA (rRNA) genes, which are widely applied in phylogenetic studies. However, it was generally thought that DNA is rapidly degraded soon after burial within sediments. Using advanced molecular biological techniques we showed that DNA of planktonic photosynthetic bacteria and algae as well as zooplankton survived degradation in Holocene anoxic, sulfidic sediments of the permanently stratified, saline Ace Lake (Vestfold Hills, Antarctica). Alkenones were predominant biomarkers in the sediment layers and their source organisms (haptophytes) were identified based on the analysis of fossil 18S rRNA genes. The quantitative comparison of the individual 18S rRNA genes and the various alkenones allowed for the first time the identification of fossil organisms and their biomarkers at the species level. It was shown that all six identified haptophyte phylotypes are closer related to the alkenone-producing haptophyte genus Isochrysis than to the genera Emiliania and Gephyrocapsa. Subtle changes in the alkenone and alkenoate composition correlated with changes in the quantitative phylotype composition of haptophytes. Implications for alkenone stratigraphy will be discussed.

  15. Results after one year from a Hydrostatic Levelling System installed at Diamond Light Source (United States)

    Kay, James; Baker, Keith A.; Hoffman, William J.


    A Hydrostatic Levelling System (HLS) has been installed at Diamond Light Source. 8 sensors have been positioned along a 60 metre portion of the floor of the Storage Ring and the Experimental Hall, stretching out along a typical beamline route from Insertion Device to sample. 7 of the sensors are installed on the thick, reinforced concrete floor of the Experimental Hall which is supported on piles and the last sensor is mounted on the much thinner concrete floor of the peripheral walkway which has no piles. The foundations and floor were designed to achieve settlements measuring 1 micron per 10 metres per hour and 10 microns per 10 metres per day. A larger range was specified of 250 microns per 10 metres per year on the Experimental Hall floor and 100 microns per 10 metres per year in the Storage Ring to account for longer term settlement effects and seasonal variation and the HLS has been installed to try and measure these very small movements. Results after one year of operation are presented.

  16. Sounds, source levels, and associated behavior of humpback whales, southeast Alaska. (United States)

    Thompson, P O; Cummings, W C; Ha, S J


    Humpback whales in Southeast Alaskan waters produced five categories of sounds: moans, grunts, pulse trains, blowhole-associated sounds, and surface impacts. Frequencies (Hz) of moans and grunts were 20-1900. Major energy in low-frequency pulse trains was in a band of 25-80 Hz with pulse duration of 300-400 ms. Blowhole-associated sounds, recorded as transiting whales encountered one another, were of two types: shrieks, 555-2000 Hz, and trumpetlike horn blasts with fundamental at 414 Hz (median). Pulses and spread spectrum noise were associated with gas bubble formation and explosive bursts, respectively, in connection with spiral feeding maneuvers. Surface impacts resulted from fluke or flipper slaps in sequences of 3-21 sounds. Source levels ranged from 162 (low-frequency pulse trains) to 192 dB (surface impacts), re: 1 microPa, 1 m. Songs, commonly heard on winter breeding grounds, were absent from our recordings. Feeding and perhaps certain other whale activities can be monitored based on sound production.

  17. Binaural masking level differences with a variety of waveforms. (United States)

    Henning, G B; Gaskell, H


    Binaural masking level differences (BMLDs) were measured in a standard two-interval forced-choice detection task. The signals were (a) 250-ms bursts of pure tones, (b) amplitude-modulated waveforms with either high- or low-frequency carriers, and (c) 20-microseconds clicks. The pure tones and clicks were presented either eith zero phase difference between the ears or with an 180 degrees phase difference between the ears: the AM tones were presented in several different interaural phase conditions, only some of which lead to changes in the apparent location of the signal source. The noise against which all the signals were detected was white, broad-band, and identical at the ears. BMLDs were invariably small with high-frequency signals and with clicks. Although the magnitude of the BMLD obtained with low-frequency signals appeared to be related to the Observers' ability to lateralize the signal, there is a simpler explanation based on the assumption that detection of low-frequency AM signals is determined by independent detection of its components.

  18. Click chemistry approach for fabricating PVA/gelatin nanofibers for the differentiation of ADSCs to keratinocytes. (United States)

    Ravichandran, Rajeswari; Venugopal, Jayarama Reddy; Sundarrajan, Subramanian; Mukherjee, Shayanti; Forsythe, John; Ramakrishna, Seeram


    Every year, millions of people suffer from dermal wounds caused by heat, fire, chemicals, electricity, ultraviolet radiation or disease. Tissue engineering and nanotechnology have enabled the engineering of nanostructured materials to meet the current challenges in skin treatments owing to such rising occurrences of accidental damages, skin diseases and defects. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for skin regeneration. The nanofibrous PVA/gelatin/azide scaffolds were then fabricated by electrospinning using water as solvent and allowed to undergo click reaction. The scaffolds were characterized by SEM, contact angle and FTIR. The cell-scaffold interactions were analyzed by cell proliferation and the results observed that the rate of cell proliferation was significantly increased (P ≤ 0.05) on PVA/gelatin/azide scaffolds compared to PVA/gelatin nanofibers. In the present study, manipulating the biochemical cues by the addition of an induction medium, in combination with environmental and physical factors of the culture substrate by functionalizing with click moieties, we were able to drive ADSCs into epidermal lineage with the development of epidermis-like structures, was further confirmed by the expression of early and intermediate epidermal differentiation markers like keratin and filaggrin. This study not only provides an insight into the design of a site-specific niche-like microenvironment for stem cell lineage commitment, but also sheds light on the therapeutic application of an alternative cell source-ADSCs, for wound healing and skin tissue reconstitution.

  19. Five-Level Current-Source Inverters With Buck–Boost and Inductive-Current Balancing Capabilities

    DEFF Research Database (Denmark)

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


    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...... verified in simulation and experimentally using a scaled-down laboratory platform....

  20. High Source Levels and Small Active Space of High-Pitched Song in Bowhead Whales (Balaena mysticetus)

    DEFF Research Database (Denmark)

    Tervo, Outi M.; Christoffersen, Mads F.; Simon, Malene


    The low frequency, powerful vocalizations of blue and fin whales may potentially be detected by conspecifics across entire ocean basins. In contrast, humpback and bowhead whales produce equally loud, but more complex broadband vocalizations composed of higher frequencies that suffer from higher...... attenuation. Here we evaluate the active space of high-pitched song notes of bowhead whales (Balaena mysticetus) in Western Greenland using measurements of song source levels and ambient noise. Four independent GPS-synchronized hydrophones were deployed through holes in the ice to localize vocalizing bowhead...... whales, estimate source levels and measure ambient noise. The song had a mean apparent source level of 185 ± 2 dB rms re 1µPa and a high mean centroid frequency of 444 ± 48 Hz. Using measured ambient noise levels in the area and Arctic sound spreading models, the estimated active space of these song...

  1. Greenhouse Gas Emissions from Ground Level Area Sources in Dairy and Cattle Feedyard Operations

    Directory of Open Access Journals (Sweden)

    Calvin B. Parnell


    Full Text Available A protocol that consisted of an isolation flux chamber and a portable gas chromatograph was used to directly quantify greenhouse gas (GHG emissions at a dairy and a feedyard operation in the Texas Panhandle. Field sampling campaigns were performed 5 consecutive days only during daylight hours from 9:00 am to 7:00 pm each day. The objective of this research was to quantify and compare GHG emission rates (ERs from ground level area sources (GLAS at dairy and cattle feedyard operations during the summer. A total of 74 air samples using flux chamber were collected from the barn (manure lane and bedding area, loafing pen, open lot, settling basin, lagoons, and compost pile within the dairy operation. For the cattle feedyard, a total of 87 air samples were collected from four corner pens of a large feedlot, runoff holding pond, and compost pile. Three primary GHGs (methane, carbon dioxide, and nitrous oxide were measured and quantified from both operations. The aggregate estimated ERs for CH4, CO2, and N2O were 836, 5573, 3.4 g hd−1 d−1 (collectively 27.5 kg carbon dioxide equivalent (CO2e hd−1 d−1, respectively, at the dairy operation. The aggregate ERs for CH4, CO2, and N2O were 3.8, 1399, 0.68 g hd−1 d−1 (1.7 kg CO2e hd−1 d−1, respectively, from the feedyard. The estimated USEPA GHG ERs were about 13.2 and 1.16 kg CO2e hd−1 d−1, respectively, for dairy and feedyard operations. Aggregate CH4, CO2 and N2O ERs at the dairy facility were about 219, 4 and 5 times higher, respectively, than those at the feedyard. At the dairy, average CH4 ERs estimated from the settling basin, primary and secondary lagoons were significantly higher than those from the other GLAS, contributing about 98% of the aggregate CH4 emission. The runoff holding pond and pen surface of the feedyard contributed about 99% of the aggregate CH4 emission. Average CO2 and N2O ERs estimated from the pen surface area were significantly higher than those estimated from

  2. Using click chemistry to modify block copolymers and their morphologies (United States)

    Wollbold, Johannes

    Microphase separated block copolymers (BCPs) are emerging as promising templates and scaffolds for the fabrication of nanostructured materials. To achieve the desired nanostructures, it is necessary to establish convenient approaches to control the morphology of BCPs. It remains challenging to induce morphological transitions of BCPs via external fields. Click chemistry, especially alkyne/azide click chemistry, has been widely used to synthesize novel functionalized materials. Here, we demonstrate that alkyne/azide click chemistry can be used as an efficient approach to chemically modify BCPs and therefore induce morphological transitions. Alkyne-functionalized diblock copolymers (di-BCPs) poly(ethylene oxide)- block-poly(n-butyl methacrylate-random-propargyl methacrylate) (PEO-b-P(nBMA-r-PgMA)) have been successfully synthesized. When the di-BCP is blended with an azide additive Rhodamine B azide and annealed at elevated temperatures, click reaction occurs between the two components. With the Rhodamine B structure attached to the polymer backbone, the di-BCP shows dramatic change in the interactions between the two blocks and the volume fraction of each block. As a result, morphological transitions, such as disorder-to-order transitions (DOTs) and order-to-order transitions (OOTs), are observed. The reaction kinetics and morphology evolution during the click chemistry induced DOTs have been investigated by in-situ and ex-situ characterizations, and fast kinetics properties are observed. Microphase separated morphologies after the DOTs or OOTs are dictated by the composition of neat di-BCPs and the mole ratio between the alkyne and azide groups. The DOTs of PEO-b-P(nBMA-r-PgMA) di-BCPs induced by alkyne/azide click chemistry have also been achieved in thin film geometries, with comparable kinetics to bulk samples. The orientation of the microdomains is dependent on the grafting density of Rhodamine B structure as well as film thickness. At higher grafting densities

  3. 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


    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....

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

    DEFF Research Database (Denmark)

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


    . 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...... in the dual-inverter PWM scheme, its switched common-mode voltage can be completely eliminated, unlike in traditional inverters, where narrow common-mode spikes are still generated. Under semiconductor failure conditions, the presented PWM schemes can easily be modified to allow the inverter to operate......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...

  5. Source term model evaluations for the low-level waste facility performance assessment

    Energy Technology Data Exchange (ETDEWEB)

    Yim, M.S.; Su, S.I. [North Carolina State Univ., Raleigh, NC (United States)


    The estimation of release of radionuclides from various waste forms to the bottom boundary of the waste disposal facility (source term) is one of the most important aspects of LLW facility performance assessment. In this work, several currently used source term models are comparatively evaluated for the release of carbon-14 based on a test case problem. The models compared include PRESTO-EPA-CPG, IMPACTS, DUST and NEFTRAN-II. Major differences in assumptions and approaches between the models are described and key parameters are identified through sensitivity analysis. The source term results from different models are compared and other concerns or suggestions are discussed.

  6. Thiol-ene click chemistry: computational and kinetic analysis of the influence of alkene functionality. (United States)

    Northrop, Brian H; Coffey, Roderick N


    The influence of alkene functionality on the energetics and kinetics of radical initiated thiol-ene click chemistry has been studied computationally at the CBS-QB3 level. Relative energetics (ΔH°, ΔH(++), ΔG°, ΔG(++)) have been determined for all stationary points along the step-growth mechanism of thiol-ene reactions between methyl mercaptan and a series of 12 alkenes: propene, methyl vinyl ether, methyl allyl ether, norbornene, acrylonitrile, methyl acrylate, butadiene, methyl(vinyl)silanediamine, methyl crotonate, dimethyl fumarate, styrene, and maleimide. Electronic structure calculations reveal the underlying factors that control activation barriers for propagation and chain-transfer processes of the step-growth mechanism. Results are further extended to predict rate constants for forward and reverse propagation and chain-transfer steps (k(P), k(-P), k(CT), k(-CT)) and used to model overall reaction kinetics. A relationship between alkene structure and reactivity in thiol-ene reactions is derived from the results of kinetic modeling and can be directly related to the relative energetics of stationary points obtained from electronic structure calculations. The results predict the order of reactivity of alkenes and have broad implications for the use and applications of thiol-ene click chemistry.

  7. One click film (OCF) dosimetry system for routine QA

    Energy Technology Data Exchange (ETDEWEB)

    Kim, So Young; Yi, Byong Yong; Kim, Jong Hoon; Ahn, Seung Do; Lee, Sang Wook; Choi, Eun Kyoung [Asan Medical Center, College of Medicine, University of Ulsan, Seoul (Korea, Republic of); Joo, Kwan Sik [MyongJi University, Yongin (Korea, Republic of)


    To develop a practical film dosimetry system for routine Quality Assurance (QA). An One Click Film (OCF) Dosimetry system was designed to perform swift routine QA with functions including automatic fog value elimination, angle adjustment, automatic symmetry calculation, and realtime profile generation with the ability to display realtime three-dimensional dose distributions. The most frequently used functions for routine QA, such as the elimination of the fog value, conversion into an H and D curve, symmetry, and isodose distribution, can be achieved with only one click. Reliable results were achieved with the OCF dosimetry with simpler steps than other commercially available film dosimetry systems for routine QA. More research on the refined user interface will make this system be clinically useful.

  8. Carbohydrate CuAAC click chemistry for therapy and diagnosis. (United States)

    He, Xiao-Peng; Zeng, Ya-Li; Zang, Yi; Li, Jia; Field, Robert A; Chen, Guo-Rong


    Carbohydrates are important as signaling molecules and for cellular recognition events, therefore offering scope for the development of carbohydrate-mimetic diagnostics and drug candidates. As a consequence, the construction of carbohydrate-based bioactive compounds and sensors has become an active research area. While the advent of click chemistry has greatly accelerated the progress of medicinal chemistry and chemical biology, recent literature has seen an extensive use of such approaches to construct functionally diverse carbohydrate derivatives. Here we summarize some of the progress, covering the period 2010 to mid-2015, in Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition CuAAC "click chemistry" of carbohydrate derivatives, in the context of potential therapeutic and diagnostic tool development.

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

    Directory of Open Access Journals (Sweden)

    Chen Qiao-Hong


    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.

  10. Click chemistry: 1,2,3-triazoles as pharmacophores. (United States)

    Agalave, Sandip G; Maujan, Suleman R; Pore, Vandana S


    The copper(I)-catalyzed 1,2,3-triazole-forming reaction between azides and terminal alkynes has become the gold standard of 'click chemistry' due to its reliability, specificity, and biocompatibility. Applications of click chemistry are increasingly found in all aspects of drug discovery; they range from lead finding through combinatorial chemistry and target-templated in vitro chemistry, to proteomics and DNA research by using bioconjugation reactions. The triazole products are more than just passive linkers; they readily associate with biological targets, through hydrogen-bonding and dipole interactions. The present review will focus mainly on the recent literature for applications of this reaction in the field of medicinal chemistry, in particular on use of the 1,2,3-triazole moiety as pharmacophore.

  11. Sources



    SOURCES MANUSCRITES Archives nationales Rôles de taille 1768/71 Z1G-344/18 Aulnay Z1G-343a/02 Gennevilliers Z1G-340/01 Ivry Z1G-340/05 Orly Z1G-334c/09 Saint-Remy-lès-Chevreuse Z1G-344/18 Sevran Z1G-340/05 Thiais 1779/80 Z1G-391a/18 Aulnay Z1G-380/02 Gennevilliers Z1G-385/01 Ivry Z1G-387b/05 Orly Z1G-388a/09 Saint-Remy-lès-Chevreuse Z1G-391a/18 Sevran Z1G-387b/05 Thiais 1788/89 Z1G-451/18 Aulnay Z1G-452/21 Chennevières Z1G-443b/02 Gennevilliers Z1G-440a/01 Ivry Z1G-452/17 Noiseau Z1G-445b/05 ...

  12. Unique tetrameric and hexameric mannoside clusters prepared by click chemistry. (United States)

    Al-Mughaid, Hussein; Al-Zoubi, Raed M; Paul, Nawal K; Grindley, T Bruce


    The synthesis of novel tetrameric and hexameric mannoside clusters bearing 1,2,3-trizole linkages via Cu(I)-catalyzed azide-alkyne cycloaddition reaction ("click chemistry") is described. An attractive feature of these multiarmed mannoside clusters as potential inhibitors of uropathogenic Escherichia coli is the use of an aglycone whose length is designed to fit in the tyrosine gate. The acetylated mannosides were deprotected and the corresponding de-O-acetylated mannosides were found to exhibit good water solubility.

  13. The Metabolic Cost of Click Production in Bottlenose Dolphins (United States)


    analysis continued through May 2014 with subsequent post-trial calibration of the instruments and metabolic baseline. APPROACH The metabolic ... metabolism , relative to baseline, for each individual trial. The results of this analysis are depicted in Figs. 3B and 4B. For both dolphins, the...period is the mass-specific metabolic rate during the submerged click production bout in ml O2 min-1 kg-1 and cEFD is the cumulative energy flux

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

    DEFF Research Database (Denmark)

    Fruergaard, Bjarne Ørum; Hansen, Lars Kai


    with varying degrees of sparsity in the representations. The decompositions that we consider are SVD, NMF, and IRM. To quantify the utility, we measure the performances of these representations when used as features in a sparse logistic regression model for click-through rate prediction. We recommend the IRM...... bipartite clustering features as they provide the most compact representation of browsing patterns and yield the best performance....

  15. Declining Groundwater Levels in North India: Understanding Sources of Irrigation Inefficiency (United States)

    O'Keeffe, J.; Buytaert, W.; Mijic, A.; Brozovic, N.


    Over the last half century, the green revolution has transformed India from a famine-prone, drought-susceptible country, into the world's third largest grain producer and one of the most intensely irrigated regions on the planet. This is in no small part due to the country's vast water resources along with an increase in tubewells and more advanced abstraction methods. While agricultural intensification has had undeniable benefits, it has, and continues to have a significant impact on water resources. Unless solutions which take into consideration the ever evolving socio-economic, hydrological and climatic conditions are found, India's agricultural future looks bleak.This research examines the irrigation behaviour of farmers, using data collected during field work in the State of Uttar Pradesh within the Ganges Basin of North India. Significant differences in farmer behaviour and irrigation practices are highlighted, not only between State districts but between individual farmers. This includes the volume of irrigation water applied and the price paid, as well as differences in the yields of crops produced. Analyses of results suggest that this is due to a number of factors, particularly the source of irrigation water. Study areas which had access to cheaper, but crucially less reliable, canal water were found to invest in more efficient water saving technologies in order to reduce the overall cost of irrigation during periods where less expensive canal water is not available. As a result, overall water use and irrigation cost is lower and yields are higher despite very similar climatic conditions. While cheap canal water is not an option for all farmers, the results show that the introduction of more efficient water saving technologies, despite the significant capital expenditure is a viable option for many farmers and costs can be recovered in a relatively short space of time. In addition, the reduction of declining water levels mean that water is abstracted from


    Directory of Open Access Journals (Sweden)



    Full Text Available A space vector PWM method for a two level inverter is proposed in this paper. A two level inverter using space vector modulation strategy has been modeled and simulated with a passive R-L load. Photovoltaic cells are used as DC source for input of two-level inverter. Simulation results are presented for various operation conditions to verify the system model. In this paper, MATLAB/Simulink package program has been used for modeling and simulation of PV cells and two-level space vector pulse width modulation (SVPWM inverter.

  17. Image Based Authentication Using Persuasive Cued Click Points

    Directory of Open Access Journals (Sweden)

    Ankita R Karia


    Full Text Available User authentication is one of the most important procedures required to access secure and confidential data. Authentication of users is usually achieved through text-based passwords. Attackers through social engineering techniques easily obtain the text based password of a user. Apart from being vulnerable to social engineering attacks, text based passwords are either weak-and-memorable or secure-but-difficult-to-remember. Researchers of modern days have thus gone for alternative methods wherein graphical pictures are used as passwords. Image based authentication allows user to create graphical password which has advantages over text-based passwords. Graphical passwords have been designed to make passwords more memorable and easier for people to use. This paper focusses on creating a password by using a sequence of images such that one click-point per image contributes to password. Persuasive Technology is used to guide user’s choice in click-based graphical passwords, inspiring users to select more random and thus more difficult to guess click-points. Also to enhance the security, a user has to decide a sequence for the images used during registration, which has to be reproduced by him during login phase.

  18. Click Chemistry in the Development of Contrast Agents for Magnetic Resonance Imaging. (United States)

    Hapuarachchige, Sudath; Artemov, Dmitri


    Click chemistry provides fast, convenient, versatile, and reliable chemical reactions that take place between pairs of functional groups of small molecules that can be purified without chromatographic methods. Due to the fast kinetics and low or no elimination of byproducts, click chemistry is a promising approach that is rapidly gaining acceptance in drug discovery, radiochemistry, bioconjugation, and nanoscience applications. Increasing use of click chemistry in synthetic procedures or as a bioconjugation technique in diagnostic imaging is occurring because click reactions are fast, provide a quantitative yield, and produce a minimal amount of nontoxic byproducts. This review summarizes the recent application of click chemistry in magnetic resonance imaging and discusses the directions for applying novel click reactions and strategies for further improving magnetic resonance imaging performance.

  19. Effect of click-polarity on abnormality of intraoperatively monitored brainstem acoustic evoked potentials. (United States)

    Mokrusch, T; Schramm, J; Hochstetter, A


    The configuration of brainstem acoustic evoked potentials (BAEP) is influenced by the type of click stimuli used and may thus affect detectability of abnormalities. In a group of 19 patients with lesions in the posterior fossa BAEP were recorded pre- and intraoperatively. Repeat recordings were performed in each patient in two alternating series with rarefaction and condensation click stimuli. The findings demonstrated that intraoperative potential changes in latency and amplitude were different between the two stimulation modes, but did not vary significantly in their incidence. It was also not possible to predict from the preoperative BAEP which click polarity would demonstrate intraoperative changes more markedly, taking latency and amplitude as parameters. Two conclusions are drawn from this study: None of the two stimulation modes is superior in detecting intraoperative changes and therefore no recommendation can be made which click polarity to use. When working with only one click polarity it is recommended to use occasional control recordings with the other click polarity.

  20. Cash Management, Revenue Sources and Cost Effective Methods of Revenue Collection at Local Government Level

    Directory of Open Access Journals (Sweden)

    Mustapha Gimba Kumshe


    Full Text Available The main objective of this paper was to focus on the elements, objectives, goals and importance of cash management; and also to examine the sources of revenue and cost effective collections for local governments. The elements of cash management are identified as establishing bank relations, preparing cash flow statements, estimating collection receipts and analyzing cash flow and preparing a budget. Amongst the objectives of cash management is to ensure availability of cash resources at all times for efficient and unconstrained implementation of the annual budget. The primary goals of a good cash management system are to maintain adequate cash at hand to meet the daily cash requirements of the local government while maximizing the amount available for investment and to obtain the maximum earnings on invested funds while ensuring their safety. The local governments obtain their revenue through internal and external sources, the external sources of revenue includes federal statutory allocations and loans obtained from financial institutions and other agencies; while among the internal sources are revenue from market fees, fees collected from motor parks, street hawking fees, shop fees and other miscellaneous sources. Some of the cost effective methods of revenue collections are contracting out of revenue collections to private collection agency, designating collection points for convenience, application of e-collection method where the local governments device a means of allowing tax payers to pay their taxes online. It is recommended that proper management of funds, efficient accounting and auditing system is necessary for proper cash management.

  1. Design of Three-Phase Three-Level CIC T-Source Inverter with Maximum Boost Control

    DEFF Research Database (Denmark)

    Shults, Tatiana; Husev, Oleksandr; Roncero-Clemente, Carlos


    This paper presents guidelines for component design of the three-level three-phase T-source inverter with continuous input current under maximum boost control proposed recently. Steady state analysis under low-frequency current and voltage ripples in the dc side was made. Component sizes for both...

  2. Low levels of H2S may replace sulfate as sulfur source in sulfate-deprived onion

    NARCIS (Netherlands)

    Durenkamp, Mark; De Kok, LJ


    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 decrease

  3. Effects of dietary dilution source and dilution level on feather damage, performance, behaviour, and litter condition in pullets

    NARCIS (Netherlands)

    Qaisrani, S.N.; Krimpen, van M.M.; Kwakkel, R.P.


    An experiment was conducted to investigate the effects of dietary dilution sources and levels on feather damage, performance, feeding behavior, and litter condition in rearing pullets. It was hypothesized that dietary dilution increases feeding-related behavior and improves feather condition, partic

  4. 10-fs-level synchronization of photocathode laser with RF-oscillator for ultrafast electron and X-ray sources (United States)

    Yang, Heewon; Han, Byungheon; Shin, Junho; Hou, Dong; Chung, Hayun; Baek, In Hyung; Jeong, Young Uk; Kim, Jungwon


    Ultrafast electron-based coherent radiation sources, such as free-electron lasers (FELs), ultrafast electron diffraction (UED) and Thomson-scattering sources, are becoming more important sources in today’s ultrafast science. Photocathode laser is an indispensable common subsystem in these sources that generates ultrafast electron pulses. To fully exploit the potentials of these sources, especially for pump-probe experiments, it is important to achieve high-precision synchronization between the photocathode laser and radio-frequency (RF) sources that manipulate electron pulses. So far, most of precision laser-RF synchronization has been achieved by using specially designed low-noise Er-fibre lasers at telecommunication wavelength. Here we show a modular method that achieves long-term (>1 day) stable 10-fs-level synchronization between a commercial 79.33-MHz Ti:sapphire laser oscillator and an S-band (2.856-GHz) RF oscillator. This is an important first step toward a photocathode laser-based femtosecond RF timing and synchronization system that is suitable for various small- to mid-scale ultrafast X-ray and electron sources.

  5. Unraveling the sources of ground level ozone in the Intermountain Western United States using Pb isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, John N. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Weiss-Penzias, Peter [University of California at Santa Cruz, Santa Cruz, CA (United States); Fine, Rebekka [University of Nevada, Reno, NV (United States); McDade, Charles E.; Trzepla, Krystyna [University of California at Davis, Crocker Nuclear Laboratory, Davis, CA (United States); Brown, Shaun T. [Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Gustin, Mae Sexauer [University of Nevada, Reno, NV (United States)


    Ozone as an atmospheric pollutant is largely produced by anthropogenic precursors and can significantly impact human and ecosystem health, and climate. The U.S. Environmental Protection Agency has recently proposed lowering the ozone standard from 75 ppbv (MDA8 = Maximum Daily 8-Hour Average) to between 65 and 70 ppbv. This will result in remote areas of the Intermountain West that includes many U.S. National Parks being out of compliance, despite a lack of significant local sources. We used Pb isotope fingerprinting and back-trajectory analysis to distinguish sources of imported ozone to Great Basin National Park in eastern Nevada. During discrete Chinese Pb events (> 1.1 ng/m{sup 3} & > 80% Asian Pb) trans-Pacific transported ozone was 5 ± 5.5 ppbv above 19 year averages for those dates. In contrast, concentrations during regional transport from the Los Angeles and Las Vegas areas were 15 ± 2 ppbv above the long-term averages, and those characterized by high-altitude transport 3 days prior to sampling were 19 ± 4 ppbv above. However, over the study period the contribution of trans-Pacific transported ozone increased at a rate of 0.8 ± 0.3 ppbv/year, suggesting that Asian inputs will exceed regional and high altitude sources by 2015–2020. All of these sources will impact regulatory compliance with a new ozone standard, given increasing global background. - Highlights: • Ozone can significantly impact human and ecosystem health and climate. • Pb isotopes and back-trajectory analysis were used to distinguish sources of O{sub 3}. • Baseline concentrations in the Western US are ~ 54 ppbv. • During discrete Asia events O{sub 3} increased by 5 ± 5.5 ppbv and during S CA events by 15 ± 2 ppbv. • Data indicate that Asian ozone inputs will exceed other sources by 2015–2020.

  6. Preparation of novel chiral stationary phase based on click chemistry for ligand exchange chromatography

    Institute of Scientific and Technical Information of China (English)

    Chun Mei Fu; Hong Yu Shi; Guang Sheng Qian; Zhang Wan Li


    Click chemistry was applied to immobilize L-proline derivative onto azide-modified silica gel to give a novel chiral stationary phase (denoted as click-CSP) for ligand exchange chromatography. The developed protocol combines the benefits of operational simplicity, exceptionally mild conditions and high surface loadings. The enantioselectivity α of some DE-amino acids on the click-CSP were found to be in the range from 1.13 to 3.46. The chromatographic resolutions of some DL-amino acids and the stability study firmly illustrate the potential of click chemistry for preparation chiral stationary phase for ligand exchange chromatography.

  7. Foraging Blainville's beaked whales (Mesoplodon densirostris) produce distinct click types matched to different phases of echolocation. (United States)

    Johnson, M; Madsen, P T; Zimmer, W M X; de Soto, N Aguilar; Tyack, P L


    Blainville's beaked whales (Mesoplodon densirostris Blainville) echolocate for prey during deep foraging dives. Here we use acoustic tags to demonstrate that these whales, in contrast to other toothed whales studied, produce two distinct types of click sounds during different phases in biosonar-based foraging. Search clicks are emitted during foraging dives with inter-click intervals typically between 0.2 and 0.4 s. They have the distinctive form of an FM upsweep (modulation rate of about 110 kHz ms(-1)) with a -10 dB bandwidth from 26 to 51 kHz and a pulse length of 270 micros, somewhat similar to chirp signals in bats and Cuvier's beaked whales (Ziphius cavirostris Cuvier), but quite different from clicks of other toothed whales studied. In comparison, the buzz clicks, produced in short bursts during the final stage of prey capture, are short (105 micros) transients with no FM structure and a -10 dB bandwidth from 25 to 80 kHz or higher. Buzz clicks have properties similar to clicks reported from large delphinids and hold the potential for higher temporal resolution than the FM clicks. It is suggested that the two click types are adapted to the separate problems of target detection and classification versus capture of low target strength prey in a cluttered acoustic environment.

  8. What is the Source Level of Pile Driving Noise in Water?

    NARCIS (Netherlands)

    Ainslie, M.A.; Jong, C.A.F. de; Robinson, S.P.; Lepper, P.A.


    To meet the growing demand for carbon-free energy sources, the European Union (EU) has ambitious plans to increase its capacity for generation of offshore wind power. The United Kingdom and The Netherlands, for example, plan to increase their offshore power-generating capacity to 33 and 6 GW, respec

  9. What is the source level of pile driving noise in water?

    NARCIS (Netherlands)

    Ainslie, M.A.; Jong, C.A.F. de; Robinson, S.P.; Lepper, P.A.


    To meet the growing demand for carbon-free energy sources, the EU has ambitious plans to increase its capacity for generation of offshore wind power. The UK and Netherlands, for example, plan to increase their offshore power generating capacity, respectively, to 33 and 6 gigawatts by the year 2020.

  10. Status of metal levels and their potential sources of contamination in Southeast Asian rivers. (United States)

    Chanpiwat, Penradee; Sthiannopkao, Suthipong


    To assess the concentration and status of metal contaminants in four major Southeast Asian river systems, water were collected from the Tonle Sap-Bassac Rivers (Cambodia), Citarum River (Indonesia), lower Chao Phraya River (Thailand), and Saigon River (Vietnam) in both dry and wet seasons. The target elements were Be, Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Ba, Tl, and Pb and the concentrations exceeded the background metal concentrations by 1- to 88-fold. This distinctly indicates enrichment by human urban area activities. The results of a normalization technique used to distinguish natural from enriched metal concentrations confirmed contamination by Al, Cd, Co, Mn, Ni, Pb, and Zn. Cluster analysis revealed the probable source of metals contamination in most sampling sites on all rivers studied to be anthropogenic, including industrial, commercial, and residential activities. Stable lead isotopes analyses applied to track the sources and pathways of anthropogenic lead furthermore confirmed that anthropogenic sources of metal contaminated these rivers. Discharges of wastewater from both industrial and household activities were major contributors of Pb into the rivers. Non-point sources, especially road runoff and street dust, also contributed contamination from Pb and other metals.

  11. A Comparison of the Burnout Levels of Teachers with Different Occupational Satisfaction Sources (United States)

    Akbaba, Sirri


    The aim of this research is to investigate whether professional satiety sources predict burnout in teachers. Professional values, including satisfaction and dissatisfaction with the teaching profession, are investigated using the Professional Satiety Inventory. Of 698 teachers, 478 primary school teachers were chosen randomly as the research…

  12. Policy Transfer Among Regional-Level Organizations: Insights from Source Water Protection in Ontario. (United States)

    de Loë, R C; Murray, D; Michaels, S; Plummer, R


    Organizations at the local and regional scales often face the challenge of developing policy mechanisms rapidly and concurrently, whether in response to expanding mandates, newly identified threats, or changes in the political environment. In the Canadian Province of Ontario, rapid, concurrent policy development was considered desirable by 19 regional organizations tasked with developing policies for protection of drinking water sources under very tight and highly prescribed mandates. An explicit policy transfer approach was used by these organizations. Policy transfer refers to using knowledge of policies, programs, and institutions in one context in the development of policies, programs, and institutions in another. This paper assesses three online mechanisms developed to facilitate policy transfer for source water protection in Ontario. Insights are based on a survey of policy planners from the 19 regional organizations who used the three policy transfer tools, supplemented by an analysis of three policies created and transferred among the 19 regional source water protection organizations. Policy planners in the study indicated they had used policy transfer to develop source protection policies for their regions-a finding confirmed by analysis of the text of policies. While the online policy transfer tools clearly facilitated systematic policy transfer, participants still preferred informal, direct exchanges with their peers in other regions over the use of the internet-based policy transfer mechanisms created on their behalf.

  13. Policy Transfer Among Regional-Level Organizations: Insights from Source Water Protection in Ontario (United States)

    de Loë, R. C.; Murray, D.; Michaels, S.; Plummer, R.


    Organizations at the local and regional scales often face the challenge of developing policy mechanisms rapidly and concurrently, whether in response to expanding mandates, newly identified threats, or changes in the political environment. In the Canadian Province of Ontario, rapid, concurrent policy development was considered desirable by 19 regional organizations tasked with developing policies for protection of drinking water sources under very tight and highly prescribed mandates. An explicit policy transfer approach was used by these organizations. Policy transfer refers to using knowledge of policies, programs, and institutions in one context in the development of policies, programs, and institutions in another. This paper assesses three online mechanisms developed to facilitate policy transfer for source water protection in Ontario. Insights are based on a survey of policy planners from the 19 regional organizations who used the three policy transfer tools, supplemented by an analysis of three policies created and transferred among the 19 regional source water protection organizations. Policy planners in the study indicated they had used policy transfer to develop source protection policies for their regions—a finding confirmed by analysis of the text of policies. While the online policy transfer tools clearly facilitated systematic policy transfer, participants still preferred informal, direct exchanges with their peers in other regions over the use of the internet-based policy transfer mechanisms created on their behalf.

  14. Effects of supplemental zinc source and level on antioxidant ability and fat metabolism-related enzymes of broilers. (United States)

    Liu, Z H; Lu, L; Wang, R L; Lei, H L; Li, S F; Zhang, L Y; Luo, X G


    The objective of the present study was to investigate the effects of dietary supplemental Zinc (Zn) source and level on antioxidant ability and fat metabolism-related enzymes of broilers. Dietary treatments included the Zn-unsupplemented corn-soybean meal basal diet (control) and basal diets supplemented with 60, 120, or 180 mg Zn/kg as Zn sulfate, Zn amino acid chelate with a weak chelation strength of 6.5 quotient of formation (Qf) (11.93% Zn) (Zn-AA W), Zn proteinate with a moderate chelation strength of 30.7 Qf (13.27% Zn) (Zn-Pro M), or Zn proteinate with an extremely strong chelation strength of 944.0 Qf (18.61% Zn) (Zn-Pro S). The results showed that dietary supplemental Zn increased (P enzymes in the abdominal fat and liver of broilers. Dietary Zn source, and an interaction between Zn source and level, had no effects on any measurements. It is concluded that dietary Zn supplementation improved Zn status and resulted in promoting antioxidant ability and activities and gene expressions of fat metabolism-related enzymes of broilers regardless of Zn source and level, and the addition of 60 mg Zn/kg to the corn-soybean meal basal diet (a total dietary Zn of approximately 90 mg/kg) was appropriate for improving the above aspects of broilers.

  15. A hybrid algorithm for stochastic single-source capacitated facility location problem with service level requirements

    Directory of Open Access Journals (Sweden)

    Hosseinali Salemi


    Full Text Available Facility location models are observed in many diverse areas such as communication networks, transportation, and distribution systems planning. They play significant role in supply chain and operations management and are one of the main well-known topics in strategic agenda of contemporary manufacturing and service companies accompanied by long-lasting effects. We define a new approach for solving stochastic single source capacitated facility location problem (SSSCFLP. Customers with stochastic demand are assigned to set of capacitated facilities that are selected to serve them. It is demonstrated that problem can be transformed to deterministic Single Source Capacitated Facility Location Problem (SSCFLP for Poisson demand distribution. A hybrid algorithm which combines Lagrangian heuristic with adjusted mixture of Ant colony and Genetic optimization is proposed to find lower and upper bounds for this problem. Computational results of various instances with distinct properties indicate that proposed solving approach is efficient.

  16. A seismic field test with a Low-level Acoustic Combustion Source and Pseudo-Noise codes (United States)

    Askeland, Bjørn; Ruud, Bent Ole; Hobæk, Halvor; Mjelde, Rolf


    The Low-level Acoustic Combustion Source (LACS) which can fire its pulses at a high rate, has been tested successfully as a seismic marine source on shallow ice-age sediments in Byfjorden at Bergen, Norway. Pseudo-Noise pulsed signals with spiky autocorrelation functions were used to detect the sediments. Each transmitted sequence lasted 10 s and contained 43 pulses. While correlation gave a blurry result, deconvolution between the near-field recordings and the streamer recordings gave a clear seismic section. Compared to the section acquired with single air-gun shots along the same profile, the LACS gave a more clear presentation of the sediments and basement.

  17. Drivers of sea-level change - using relative sea level records from the North and South Atlantic to fingerprint sources of mid-Holocene ice melt (United States)

    Horton, B.; Khan, N.; Ashe, E.; Kopp, R. E.; Long, A. J.; Gehrels, W. R.


    Many factors give rise to relative sea-level (RSL) changes that are far from globally uniform. For example, spatially variable sea-level responses arise because of the exchange of mass between ice sheets and oceans. Gravitational, flexural, and rotational processes generate a distinct spatial pattern - or "fingerprint" - of sea-level change associated with each shrinking land ice mass. As a land ice mass shrinks, sea-level rise is greater in areas geographically distal to the ice mass than in areas proximal to it, in large part because the gravitational attraction between the ice mass and the ocean is reduced. Thus, the U.S. mid-Atlantic coastline experiences about 50% of the global average sea-level-rise due to Greenland Ice Sheet melt, but about 120% of the global average due to West Antarctic Ice Sheet melt. Separating the Greenland and Antarctic ice sheet contributions during the past 7,000 years requires analysis of sea-level changes from sites in the northern and southern hemisphere. Accordingly we present sea-level records within a hierarchical statistical modeling to: (1) quantify rates of change; (2) compare rates of change among sites, including full quantification of the uncertainty in their differences; and (3) test hypotheses about the sources of meltwater through their sea-level fingerprints. Preliminary analysis of three sites within our North and South Atlantic sea-level database indicates sea-level gradient in the rate of RSL rise during the mid Holocene between 6000 and 4000 years BP; a greater change in rate is found in Brazil than St Croix than New Jersey, consistent with an increase and then decrease in Greenland Ice Sheet mass.

  18. Urban background levels of particle number concentration and sources in Vilnius, Lithuania (United States)

    Byčenkienė, Steigvilė; Plauškaitė, Kristina; Dudoitis, Vadimas; Ulevicius, Vidmantas


    This study presents results of research on urban aerosol particles with a focus on the aerosol particle number concentration (PNC) and the particle size distribution. The real time measurements of aerosol PNC (> 4.5 nm) and number size distributions (9-840 nm) were performed. The seasonal variations essentially comprised the minimum monthly mean in October 2010 (3400 ± 3000 cm- 3) and the maximum in April 2011 (19,000 ± 15,000 cm- 3). The mean annual PNC was 10,000 ± 8000 cm- 3 with an average mode size of 30-50 nm. The presence of strong diurnal patterns in aerosol PNC was evident as a direct effect of three sources of aerosol particles (nucleation, traffic, and residential heating). Hybrid receptor modeling potential source contribution function (PSCF) and concentration weighted trajectory (CWT) were used by incorporating 72-h backward trajectories and measurements of PNC in Vilnius. The results of trajectory clustering and the PSCF method demonstrated that possible additional source areas contributing to the elevated particle number concentration in Vilnius could be industrial areas in central Europe. Principal component analysis (PCA) revealed highest loadings for PNC, PM10, NOx, NO, NO2 and SO2 concentrations, indicating combustion processes occurring in vehicle engines and use of sulfur-containing fossil fuels for residential heating.

  19. Evaluation of the choline status in mink fed different levels and sources of choline

    DEFF Research Database (Denmark)

    Hedemann, Mette Skou; Damgaard, Birthe Marie; Clausen, T.N.;


    plasma samples were extracted to analyze the content of free choline and betaine by liquid chromatography-mass spectrometry. Plasma choline was only increased in mink kits fed the highest level of choline whereas plasma choline dit not change in full-grown mink irrespectively of choline level in the feed....... Plasma betaine increased when the level of choline in the diet increased. The changes in plasma betaine were most prominent in mink kits. The present study shows that plasma betaine may be a more reliable marker of choline status than plasma choline, especially in mink kits....

  20. Source identification and budget analysis on elevated levels of formaldehyde within ship plumes: a photochemical/dynamic model analysis (United States)

    Song, C. H.; Kim, H. S.; von Glasow, R.; Brimblecombe, P.; Kim, J.; Park, R. J.; Woo, J. H.


    Elevated levels of formaldehyde (HCHO) along the ship corridors have been observed by satellite sensors, such as ESA/ERS-2 GOME (Global Ozone Monitoring Experiment), and were also predicted by global 3-D chemistry-transport models. In this study, three likely sources of the elevated HCHO levels were investigated to identify the detailed sources and examine the contributions of the sources (budget) of the elevated levels of HCHO in the ship corridors using a newly-developed ship-plume photochemical/dynamic model: (1) primary HCHO emission from ships; (2) secondary HCHO production via the atmospheric oxidation of Non-methane volatile organic compounds (NMVOCs) emitted from ships; and (3) atmospheric oxidation of CH4 within the ship plumes. From multiple ship-plume model simulations, CH4 oxidation by elevated levels of in-plume OH radicals was found to be the main factor responsible for the elevated levels of HCHO in the ship corridors. More than ~91% of the HCHO for the base ship plume case (ITCT 2K2 ship-plume case) is produced by this atmospheric chemical process, except in the areas close to the ship stacks where the main source of the elevated HCHO levels would be primary HCHO from the ships (due to the deactivation of CH4 oxidation from the depletion of in-plume OH radicals). Because of active CH4 oxidation (chemical destruction of CH4) by OH radicals, the instantaneous chemical lifetime of CH4 (τ CH4) decreased to ~0.45 yr inside the ship plume, which is in contrast to τ CH4 of ~1.1 yr in the background (up to ~41% decrease). A variety of likely ship-plume situations at three locations at different latitudes within the global ship corridors was also studied to determine the extent of the enhancements in the HCHOlevels in the marine boundary layer (MBL) influenced by ship emissions. It was found that the ship-plume HCHO levels could be 20.5-434.9 pptv higher than the background HCHO levels depending on the latitudinal locations of the ship plumes (i

  1. A single-phase multi-level D-STATCOM inverter using modular multi-level converter (MMC) topology for renewable energy sources (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.

  2. Effects of Heterogeneity and Uncertainties in Sources and Initial and Boundary Conditions on Spatiotemporal Variations of Groundwater Levels (United States)

    Zhang, Y. K.; Liang, X.


    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.

  3. Click Cross-Linking-Improved Waterborne Polymers for Environment-Friendly Coatings and Adhesives. (United States)

    Hu, Jianqing; Peng, Kaimei; Guo, Jinshan; Shan, Dingying; Kim, Gloria B; Li, Qiyao; Gerhard, Ethan; Zhu, Liang; Tu, Weiping; Lv, Weizhong; Hickner, Michael A; Yang, Jian


    Waterborne polymers, including waterborne polyurethanes (WPU), polyester dispersions (PED), and polyacrylate emulsions (PAE), are employed as environmentally friendly water-based coatings and adhesives. An efficient, fast, stable, and safe cross-linking strategy is always desirable to impart waterborne polymers with improved mechanical properties and water/solvent/thermal and abrasion resistance. For the first time, click chemistry was introduced into waterborne polymer systems as a cross-linking strategy. Click cross-linking rendered waterborne polymer films with significantly improved tensile strength, hardness, adhesion strength, and water/solvent resistance compared to traditional waterborne polymer films. For example, click cross-linked WPU (WPU-click) has dramatically improved the mechanical strength (tensile strength increased from 0.43 to 6.47 MPa, and Young's modulus increased from 3 to 40 MPa), hardness (increased from 59 to 73.1 MPa), and water resistance (water absorption percentage dropped from 200% to less than 20%); click cross-linked PED (PED-click) film also possessed more than 3 times higher tensile strength (∼28 MPa) than that of normal PED (∼8 MPa). The adhesion strength of click cross-linked PAE (PAE-click) to polypropylene (PP) was also improved (from 3 to 5.5 MPa). In addition, extra click groups can be preserved after click cross-linking for further functionalization of the waterborne polymeric coatings/adhesives. In this work, we have demonstrated that click modification could serve as a convenient and powerful approach to significantly improve the performance of a variety of traditional coatings and adhesives.

  4. Two Probabilistic Methods for Attributing the Sources of Sea-Level Rise from Sparse Tide Gauge Records (United States)

    Hay, C.; Morrow, E.; Kopp, R. E., III; Mitrovica, J. X.


    Recent estimates of 20th century global mean sea-level (GMSL) rise are in the range 1.6-1.9 mm/yr. However, these estimates use a temporally and spatially sparse network of tide gauge observations that may result in a biased estimate due to the incomplete sampling of a global field. Furthermore, this sparse sampling makes resolving the GMSL change into individual sources (e.g., mass loss from individual ice sheets and mountain glaciers, ocean thermal expansion, etc.) challenging. We have employed two different statistical techniques, a multi-model Kalman smoother (KS) and Gaussian process regression (GPR), to address the above challenges. Both techniques naturally accommodate spatio-temporal changes in the availability of tide gauge observations and use models of glacial isostatic adjustment, ocean dynamics, and the sea-level fingerprints of rapid land ice melt to exploit both the spatial and temporal information within observations of the sparsely-sampled global field. We present reconstructions of the global sea-level field estimated with both methods, as well as the associated constraints on the underlying sources of global mean sea-level change. Our results include estimates of the individual contributions of the world's ice sheets and mountain glaciers to 20th century sea-level change and provide new estimates of the spatial and temporal variability in sea level since 1900.

  5. Overview of Accelerator Physics Studies and High Level Software for the Diamond Light Source

    CERN Document Server

    Bartolini, Riccardo; Belgroune, Mahdia; Christou, Chris; Holder, David J; Jones, James; Kempson, Vince; Martin, Ian; Rowland, James H; Singh, Beni; Smith, Susan L; Varley, Jennifer Anne; Wyles, Naomi


    DIAMOND is a 3 GeV synchrotron light source under construction at Rutherford Appleton Laboratory in Oxfordshire (UK). The accelerators complex consists of a 100 MeV LINAC, a full energy booster and a 3GeV storage ring with 22 straight sections available for IDs. Installation of all three accelerators has begun, and LINAC commissioning is due to start in Spring 2005. This paper will give an overview of the accelerator physics activity to produce final layouts and prepare for the commissioning of the accelerator complex. The DIAMOND facility is expected to be operational for users in 2007

  6. Comparison of selenium levels and sources and dietary fat quality in diets for broiler breeders and layer hens. (United States)

    Leeson, S; Namkung, H; Caston, L; Durosoy, S; Schlegel, P


    Two experiments were carried out with broiler breeders (experiment 1) and laying hens (experiment 2) to study the effects of Se sources, in interaction with dietary level of Se or dietary fats on performance, Se incorporation into tissues (blood, liver, breast muscle, and egg) and eggs, hatchability, and glutathione peroxidase (GPX) activities in tissues and blood. Both experiments involved a 3 x 2 factorial arrangement of 3 Se sources (selenite, Se yeast, or B-Traxim Se) and either 2 levels of each source (0.1 or 0.3 mg/kg) or 2 fats (fresh or oxidized). Egg production was not affected by Se source or dietary fat in both experiments. Egg production was greater (P Hatchability of eggs from hens fed 0.1 mg/kg of Se was lower (P Selenium in egg, liver, and breast muscle was greater (P Selenium contents in liver and breast muscle were greater (P < 0.01) in hens fed Se yeast compared with hens fed other sources of Se. In experiment 1, liver GPX was greater (P < 0.01) in hens fed selenite or Se yeast, whereas plasma GPX was greater (P < 0.01) in hens fed selenite compared with B-Traxim Se or Se yeast. Supplementation with oxidized fat increased (P < 0.05) GPX in blood and liver. B-Traxim Se decreased (P < 0.05) malondialdehyde content in breast muscle of layers. It is concluded that broiler breeders require supplementation of 0.3 mg/kg of Se, and that there are numerous measurable advantages in using organic rather than inorganic sources for both breeders and layers.

  7. Specific and quantitative labeling of biomolecules using click chemistry. (United States)

    Horisawa, Kenichi


    Specific and highly efficient fluorescent labeling techniques for biomolecules, especially for proteins, are required for the quantitative analyses of bio-phenomena and for subsequent systems biology. Although expression of exogenous proteins fused with fluorescent tags, such as green fluorescent protein, is the most widely used method for quantitative bio-analysis, the following problems need to be considered carefully: (1) precise stoichiometric control in living cells is difficult, and (2) the bulkiness of the fluorescent tags restricts analysis of the inherent physical and biological properties of the proteins. Therefore, novel techniques to specifically and stoichiometrically label intrinsic proteins or other biomolecules in living cells should be developed. Click chemistry reactions (e.g., Huisgen cycloaddition and Staudinger ligation) are the most promising approaches for this purpose, because these chemical reactions have following advantages: (1) bioorthogonal reactions; (2) mild reaction conditions suitable for fragile biomolecules, cells, and tissues; (3) extremely high reaction ratio; (4) small size of the functional groups for the cross-coupling reactions; (5) stable covalent bonding; and (6) simple metabolic labeling procedures in living cells, using various biomolecular analogs. Diverse quantitative biological studies have been carried out using this technology (e.g., quantification of novel synthesized proteins and observation of post-translational modifications). In this review, I explain the basics of chemical probing with click chemistry, and discuss its recent applications in the field of quantitative biology. Furthermore, I discuss the capability, significance, and future of the chemical probing of proteins, with an emphasis on the use of click chemistry in the field of the quantitative biology.

  8. Specific and quantitative labeling of biomolecules using click chemistry

    Directory of Open Access Journals (Sweden)

    Kenichi eHorisawa


    Full Text Available Specific and highly efficient fluorescent labeling techniques for biomolecules, especially for proteins, are required for the quantitative analyses of bio-phenomena and for subsequent systems biology. Although expression of exogenous proteins fused with fluorescent tags, such as green fluorescent protein, is the most widely used method for quantitative bio-analysis, the following problems need to be considered carefully: 1 precise stoichiometric control in living cells is difficult, and 2 the bulkiness of the fluorescent tags restricts analysis of the inherent physical and biological properties of the proteins. Therefore, novel techniques to specifically and stoichiometrically label intrinsic proteins or other biomolecules in living cells should be developed. Click chemistry reactions (e.g., Huisgen cycloaddition and Staudinger ligation are the most promising approaches for this purpose, because these chemical reactions have following advantages: 1 bioorthogonal reactions; 2 mild reaction conditions suitable for fragile biomolecules, cells, and tissues; 3 extremely high reaction ratio; 4 small size of the functional groups for the cross-coupling reactions; 5 stable covalent bonding; and 6 simple metabolic labeling procedures in living cells, using various biomolecular analogs. Diverse quantitative biological studies have been carried out using this technology (e.g., quantification of novel synthesized proteins and observation of post-translational modifications. In this review, I explain the basics of chemical probing with click chemistry, and discuss its recent applications in the field of quantitative biology. Furthermore, I discuss the capability, significance, and future of the chemical probing of proteins, with an emphasis on the use of click chemistry in the field of the quantitative biology.

  9. Mercury pollution in fish from South China Sea: levels, species-specific accumulation, and possible sources. (United States)

    Liu, Jinling; Xu, Xiangrong; Yu, Shen; Cheng, Hefa; Hong, Yiguo; Feng, Xinbin


    Both total mercury (THg) and methylmercury (MeHg) levels in fish collected from South China Sea (SCS) were studied to understand Hg pollution in Chinese tropical marine ecosystems. The average THg concentrations in fish species ranged from 39.6 μg/kg for rabbitfish (Siganus fuscessens) to 417 μg/kg for thornfish (Terapon jarbua), while those of MeHg varied from 13 μg/kg (rabbitfish) to 176 μg/kg (thornfish). The median values of MeHg/THg ratios in different fish species ranged from 36 to 85%. Significant inter-species differences of THg and MeHg in fish were observed due to feeding habits and fish sizes. Overall, carnivorous fish had higher levels of THg, MeHg and MeHg/THg ratios than omnivorous and herbivorous fish. High Hg levels in fish of the SCS were probably related to Hg input from atmospheric deposition and anthropogenic activities.

  10. 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....

  11. A multi-hypothesis tracker for clicking whales. (United States)

    Baggenstoss, Paul M


    This paper describes a tracker specially designed to track clicking beaked whales using widely spaced bottom-mounted hydrophones, although it can be adapted to different species and sensors. The input to the tracker is a sequence of static localization solutions obtained using time difference of arrival information at widely spaced hydrophones. To effectively handle input localizations with high ambiguity, the tracker is based on multi-hypothesis tracker concepts, so it considers all potential association hypotheses and keeps a large number of potential tracks in memory. The method is demonstrated on actual data and shown to successfully track multiple beaked whales at depth.

  12. Superstructures of fluorescent cyclodextrin via click-reaction

    Directory of Open Access Journals (Sweden)

    Arkadius Maciollek


    Full Text Available Mono-(6-azido-6-deoxy-β-cyclodextrin (CD was covalently attached to an alkyne-modified 5-methyl-2-(pyridin-2-ylthiazol-4-ol yielding a fluorophore containing CD in a click-type reaction. Intermolecular complexes were formed by poly(host–guest-interactions. The supramolecular structures were characterized by 1H NMR-ROESY spectroscopy, dynamic light scattering, UV–vis spectroscopy, fluorescence spectroscopy, and asymmetric flow field-flow fractionation. By adding potassium adamantane-1-carboxylate, the thiazol dye is displaced from the CD-cavity and the elongated noncovalent polymeric structures collapse.

  13. Click Reactions and Boronic Acids: Applications, Issues, and Potential Solutions

    Directory of Open Access Journals (Sweden)

    Chaofeng Dai


    Full Text Available Boronic acids have been widely used in a wide range of organic reactions, in the preparation of sensors for carbohydrates, and as potential pharmaceutical agents. With the growing importance of click reactions, inevitably they are also applied to the synthesis of compounds containing the boronic acid moiety. However, such applications have unique problems. Chief among them is the issue of copper-mediated boronic acid degradation in copper-assisted [2,3]-cycloadditions involving an alkyne and an azido compound as the starting materials. This review summarizes recent developments, analyzes potential issues, and discusses known as well as possible solutions.

  14. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

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


    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....... The method has been applied for anchoring of the chelating agent nitrilotriacetic acid (NTA) on the conductive polymer. The chelating linkage ability of NTA on the surface was investigated through a sandwich ELISA study confirming the selective bonding of a histidine tagged protein....

  15. Conductive dendrimers obtained by click chemistry (United States)

    Lewis, Donald G.; Krasnova, Larissa B.; Skinner, Philip J.; Fokin, Valery V.


    First generation dendrimers having a high level of size/shape/symmetry homogeneity were fabricated using a synthetic scheme that employs highly quantitative copper-catalyzed azide-alkyne cycloaddition (CuAAC) reactions in combination with a molecular architecture that favors homogeneity. An "outside-in" or convergent synthetic approach was employed wherein dendrons having Sierpinski triangular fractal architectures were coupled to core structures having D2h or D3h point group symmetries to form the desired dendrimers. The individual dendrons consisted of branched-backbone conductive polymers having benzene branch points and 1,2,3-triazole linkages with uninterrupted π-electron cloud overlap throughout. Each dendron was then coupled to a benzene core structure having acetylene substituents by means of a CuAAC reaction so as to extend the uninterrupted π-conjugation from the dendron to the core structure for imparting conductivity throughout the entire dendrimer. The resulting dendrimers maintained the point group symmetry of their core structure, with the core structure serving to electronically couple the dendrons to one another by extension of their uninterrupted π-electron systems. Synthesis of these first generation dendrimers provides a proof of principle for the synthesis of higher generation conductive dendrimers. Since the nanophotonic properties of conductive dendrimers may be dependent, at least in some instances, upon their size, shape, and symmetry, enhancements with respect to their homogeneity may unmask new nanophotonic properties.

  16. The sources of foreign language speaking anxiety and the relationship between proficiency level and degree of foreign language speaking anxiety


    Balemir, Serkan Hasan


    Ankara : The Department of Teaching English as a Foreign Language, Bilkent University, 2009. Thesis (Master's) -- Bilkent University, 2009. Includes bibliographical references leaves 87-91. This study investigated the sources of foreign language speaking anxiety and the relationship between proficiency levels and degree of foreign language speaking anxiety. The study was conducted at Hacettepe University, with the participation of 234 students from the departments of Basic E...

  17. Knowledge Sources in EFL Learners' Lexical Inferencing across Reading Proficiency Levels (United States)

    Kaivanpanah, Shiva; Soltani Moghaddam, Majid


    Growing concerns have been voiced about strategies employed in L2 reading in general and dealing with unknown words in particular. Among other strategies, lexical inferencing has received attention in the literature. However, more research is needed to further clarify how different levels of L2 reading proficiency may affect the readers'…

  18. Sources of variation in milk flow characteristics at udder and quarter levels

    NARCIS (Netherlands)

    Tancin, V.; Ipema, A.H.; Hogewerf, P.H.; Macuhova, J.


    The aim of this study was to describe and analyze effects of parity, stage of lactation, milkability (3 groups of cows with differing peak flow rates), time of milking, and quarter position on milk production and milk flow measures at udder and quarter levels. Particular emphasis was put on changes

  19. Sources of innovation, their combinations and strengths – benefits at the NPD project level

    DEFF Research Database (Denmark)

    Tranekjer, Tina Lundø; Søndergaard, Helle Alsted


    and expands existing research by investigating how the mix of external partner types as well as the relationship strength is related to performance at the project level. The empirical background is a survey conducted among Danish SMEs in 2010. Ordinary least square regressions reveal that firms should...

  20. A Battery-less Grid Connected Photovoltaic Power generation using Five-Level Common-Emitter Current-Source Inverter

    Directory of Open Access Journals (Sweden)

    Suroso Suroso


    Full Text Available Renewable power generation using photovoltaic is very interesting to be developed to deal with the problems of conventional energy sources and environmental issues. The photovoltaic power generation can operate both in stand-alone and grid-connected operations. This paper presents an application of the five-level common-emitter current-source inverter (CE-CSI for grid connected photovoltaic system without batteries as energy storage system. In the proposed system, the five-level CE-CSI works generating a sinusoidal output current from photovoltaic system to be injected into the power grid. The transformer is used in the system to step-down the grid voltage to meet the voltage level of the photovoltaic system, and also works as a galvanic insulation between the power grid and the inverter system. Two conditions of the power grid voltage, i.e. a pure sinusoidal and a distorted power grid, are tested through computer simulation using PSIM software. Furthermore, experimental test result of the five-level inverter is also presented. The test results show that the five-level CE-CSI works well injecting a sinusoidal current into the power grid with low harmonic contents, and with unity power factor operation. The results also show that the distorted grid voltage affects the harmonic contents of the current injected by the inverter.

  1. Volatile aromatic compounds in Mexico City atmosphere: levels and source apportionment

    Energy Technology Data Exchange (ETDEWEB)

    Mugica, V. [Universidad Autonoma Metropolitana - Unidad Azcapotzalco, Mexico, D.F. (Mexico); Ruiz, M.E. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Watson, J.; Chow, J. [Desert Research Institute, Reno, Nevada (United States)


    Samples of ambient air were simultaneously collected at three different sites of Mexico City in March of 1997 in order to quantify the most abundant volatile aromatic compounds and estimate the source contributions by application of the chemical mass balance model (CMB). Volatile aromatic compounds were around 20% of the total of non-methane hydrocarbons present in morning air samples. The most abundant volatile aromatic species in urban air were toluene and xylenes followed by 1, 2, 4 trimethylbenzene, benzene, ethylbenzene, metaethyltoluene, 1, 3, 5 trimethylbenzene, styrene, n propylbenzene, and isopropylbenzene. Sampling campaigns were carried out at crossroads, a bus station, a parking place, and areas where solvents and petroleum distillates are used, with the objective of determining people's exposure to volatile aromatic compounds. The CMB was applied for estimating the contribution of different sources to the presence of each one of the most abundant aromatic compounds. Motor vehicle exhaust was the main source of all aromatic compounds, especially gasoline exhaust, although diesel exhausts and asphalt operations also accounted for toluene, xylenes, ethylbenzene, propylbenzenes, and styrene. Graphic arts and paint applications had an important impact on the presence of toluene. [Spanish] Se colectaron simultaneamente muestras de aire ambiente en tres sitios de la Ciudad de Mexico durante el mes de marzo de 1997 con el fin de conocer las concentraciones y el origen de compuestos aromaticos utilizando el modelo de balance de masa de especies quimicas (CMB). Los compuestos aromaticos volatiles representaron alrededor del 20% del total de hidrocarburos no metalicos presentes en las muestras matutinas colectadas. Las especies aromaticas volatiles mas abundantes en el ambiente fueron el tolueno y los xilenos, seguidos por 1, 2, 4 trimetilbenceno, benceno, etilbenceno, metaetiltolueno, nporpilbenceno, isopropilbenceno, 1, 3, 5 trimetilbenceno y estireno. Se

  2. Intrinsic Noise Level of Noise Cross-Correlation Functions and its Implication to Source Population of Ambient noises (United States)

    Chen, Ying-Nien; Gung, Yuancheng; Chiao, Ling-Yun; Rhie, Junkee


    SUMMARYWe present a quantitative procedure to evaluate the intrinsic noise level (INL) of the noise cross-correlation function (NCF). The method is applied to realistic NCFs derived from the continuous data recorded by the seismic arrays in Taiwan and Korea. The obtained temporal evolution of NCF noise level follows fairly the prediction of the theoretical formulation, confirming the feasibility of the method. We then apply the obtained INL to the assessment of data quality and the source characteristics of ambient noise. We show that the INL-based signal-to-noise ratio provides an exact measure for the true noise level within the NCF and better resolving power for the NCF quality, and such measurement can be implemented to any time windows of the NCFs to evaluate the quality of overtones or coda waves. Moreover, since NCF amplitudes are influenced by both the population and excitation strengths of noises, while INL is primarily sensitive to the overall source population, with information from both measurements, we may better constrain the source characteristics of seismic ambient noises.

  3. Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter

    Directory of Open Access Journals (Sweden)

    Zulkifilie Bin Ibrahim


    Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM.  SPWM is the most simple modulation technique that can realize easily in analog circuit.  However, it has some drawbacks such as higher total harmonic distortion (THD, lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM where SVPWM shows better performance than SPWM in terms of THD.

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

    NARCIS (Netherlands)

    Li, Rongmei


    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 use

  5. The Evolution of Click-n-Mortar E-tailing in Denmark

    DEFF Research Database (Denmark)

    Bøge Sørensen, Lars; Holst, Lisa L.


    The paper at hand presents an extension and application of Kotzab & Madlbergers (Kotzab &Madlberger, 2001) original clicks-and-mortar web-scan framework, which is here used to reexaminethe click-and-mortar activities of the top 100 Danish retailers and compare with resultsfrom the identical study...

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

    DEFF Research Database (Denmark)

    Vadapoo, Sundar Raja


    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...

  7. Facile modification of silica substrates provides a platform for direct-writing surface click chemistry. (United States)

    Oberhansl, Sabine; Hirtz, Michael; Lagunas, Anna; Eritja, Ramon; Martinez, Elena; Fuchs, Harald; Samitier, Josep


    Please click here: a facile two-step functionalization strategy for silicon oxide-based substrates generates a stable platform for surface click chemistry via direct writing. The suitability of the obtained substrates is proven by patterning with two different direct-writing techniques and three different molecules.

  8. 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

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

    DEFF Research Database (Denmark)

    Beedholm, K.; Møhl, Bertel


    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....

  10. 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.


    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

  11. Preliminary analysis on the tectonic stress level in the source region of Tangshan earthquake

    Institute of Scientific and Technical Information of China (English)

    赵建涛; 崔效锋; 谢富仁


    The abundant data of focal mechanism solutions in Tangshan region, China, are inverted for the tectonic stress field. Combined with tectonophysical consideration, the magnitude of the three principal stresses, as well as their vertical variation under the average crustal rock property, in the source region of the 1976 Tangshan earthquake is estimated. The relationship between crustal stress and friction (c, pore pressure P0 and stress shape factor ( is studied. The paper draws the conclusion that the vertical increasing rate of the maximum principal stress ( is directly proportional to friction, and inversely to pore pressure P0 and stress shape factor ( ; while the vertical increasing rate of the minimum principal tress ( is directly proportional to pore pressure P0, inversely to friction (c and stress shape factor (. This study is a try to invert the data of focal mechanism solutions for the complete stress tensor.

  12. Salt intake of children and adolescents in South London: consumption levels and dietary sources. (United States)

    Marrero, Naomi M; He, Feng J; Whincup, Peter; Macgregor, Graham A


    Since 2003/2004, the United Kingdom has implemented a salt reduction campaign; however, there are no data on salt intake in children as assessed by 24-hour urinary sodium, the gold standard method, to inform this campaign. We performed a cross-sectional study, involving South London school children across 3 age tiers: young children (5- to 6-year olds), intermediate-aged children (8- to 9-year olds), and adolescents (13- to 17-year olds). Dietary salt intake was measured by 24-hour urinary sodium excretion and compared with newly derived maximum salt intake recommendations. In addition, dietary sources of salt were assessed using a 24-hour photographic food diary. Valid urine collections were provided by 340 children (162 girls, 178 boys). The mean salt intakes were 3.75 g/d (95% confidence interval, 3.49-4.01), 4.72 g/d (4.33-5.11), and 7.55 g/d (6.88-8.22) for the 5- to 6-year olds, 8- to 9-year olds, and 13- to 17-year olds, respectively. Sixty-six percent of the 5- to 6-year olds, 73% of the 8- to 9-year olds, and 73% of 13- to 17-year olds had salt intake above their maximum daily intake recommendations. The major sources of dietary salt intake were cereal and cereal-based products (36%, which included bread 15%), meat products (19%), and milk and milk products (11%). This study demonstrates that salt intake in children in South London is high, with most of the salt coming from processed foods. Much further effort is required to reduce the salt content of manufactured foods.

  13. Modelling street level PM10 concentrations across Europe: source apportionment and possible futures (United States)

    Kiesewetter, G.; Borken-Kleefeld, J.; Schöpp, W.; Heyes, C.; Thunis, P.; Bessagnet, B.; Terrenoire, E.; Fagerli, H.; Nyiri, A.; Amann, M.


    Despite increasing emission controls, particulate matter (PM) has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter traffic stations and 80% of the stations which exceeded the EU air quality limit values in 2009. As a validation, we compare modelled trends in the period 2000-2008 to observations, which are well reproduced. The modelling scheme is applied here to quantify explicitly source contributions to ambient concentrations at several critical monitoring stations, displaying the differences in spatial origin and chemical composition of urban roadside PM10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are largely eliminated in a scenario applying the best available emission control technologies to the maximal technically feasible extent.

  14. A Low-Tech, Low-Budget Storage Solution for High Level Radioactive Sources

    Energy Technology Data Exchange (ETDEWEB)

    Brett Carlsen; Ted Reed; Todd Johnson; John Weathersby; Joe Alexander; Dave Griffith; Douglas Hamelin


    The need for safe, secure, and economical storage of radioactive material becomes increasingly important as beneficial uses of radioactive material expand (increases inventory), as political instability rises (increases threat), and as final disposal and treatment facilities are delayed (increases inventory and storage duration). Several vendor-produced storage casks are available for this purpose but are often costly — due to the required design, analyses, and licensing costs. Thus the relatively high costs of currently accepted storage solutions may inhibit substantial improvements in safety and security that might otherwise be achieved. This is particularly true in areas of the world where the economic and/or the regulatory infrastructure may not provide the means and/or the justification for such an expense. This paper considers a relatively low-cost, low-technology radioactive material storage solution. The basic concept consists of a simple shielded storage container that can be fabricated locally using a steel pipe and a corrugated steel culvert as forms enclosing a concrete annulus. Benefits of such a system include 1) a low-tech solution that utilizes materials and skills available virtually anywhere in the world, 2) a readily scalable design that easily adapts to specific needs such as the geometry and radioactivity of the source term material), 3) flexible placement allows for free-standing above-ground or in-ground (i.e., below grade or bermed) installation, 4) the ability for future relocation without direct handling of sources, and 5) a long operational lifetime . ‘Le mieux est l’ennemi du bien’ (translated: The best is the enemy of good) applies to the management of radioactive materials – particularly where the economic and/or regulatory justification for additional investment is lacking. Development of a low-cost alternative that considerably enhances safety and security may lead to a greater overall risk reduction than insisting on

  15. Lead in School Children from Morelos, Mexico: Levels, Sources and Feasible Interventions (United States)

    Farías, Paulina; Álamo-Hernández, Urinda; Mancilla-Sánchez, Leonardo; Texcalac-Sangrador, José Luis; Carrizales-Yáñez, Leticia; Riojas-Rodríguez, Horacio


    Background: Lead is a pervasive pollutant, associated at low levels to many adverse health effects. Objective: To investigate lead levels, exposure pathways and intervention possibilities in school children from Alpuyeca, in Morelos, Mexico. Methods: Blood lead concentrations (BPb) were measured in 226 children in 2011. Exposure pathways were assessed through a questionnaire, lead measurements in different environmental matrices and spatial aggregation analysis of lead concentrations. Results: BPb ranged from 1.5 to 36.5 µg/dL, with a mean (SD) of 7.23 (4.9) µg/dL. Sixty-four and 18% of the children had BPb > 5 µg/dL and > 10 µg/dL, respectively. The use of lead glazed ceramics was reported in almost half of the households; it was the main BPb determinant and it was associated with an increased risk of having BPb > 5 g/dL by 2.7 times (p = 0.001). Environmental samples were within US EPA’s lead recommended limits, and blood lead levels were randomly distributed in the community. Conclusions: Lead remains a public health problem in Alpuyeca, Mexico. Unlike other local pollutants, lead exposure prevention can be achieved inexpensively and in a short term. Interventions should make mothers aware of lead’s health effects and empower them to safeguard their children’s health by avoiding the culturally ingrained use of lead glazed pottery. PMID:25493390

  16. Efficient Functionalization of Oxide-Free Silicon(111) Surfaces: Thiol–yne versus Thiol–ene Click Chemistry

    NARCIS (Netherlands)

    Bhairamadgi, N.S.; Gangarapu, S.; Caipa Campos, M.A.; Paulusse, J.M.J.; Rijn, van C.J.M.; Zuilhof, H.


    Thiol-yne click (TYC) chemistry was utilized as a copper-free click reaction for the modification of alkyne-terminated monolayers on oxide-free Si(111) surfaces, and the results were compared with the analogous thiol–ene click (TEC) chemistry. A wide range of thiols such as 9-fluorenylmethoxy-carbon

  17. Efficient Functionalization of Oxide-Free Silicon(111) Surfaces: Thiol-yne versus Thiol-ene Click Chemistry

    NARCIS (Netherlands)

    Bhairamadgi, N.S.; Gangarapu, S.; Caipa Campos, M.A.; Paulusse, J.M.J.; Rijn, van C.J.M.; Zuilhof, H.


    Thiol-yne click (TYC) chemistry was utilized as a copper-free click reaction for the modification of alkyne-terminated monolayers on oxide-free Si(111) surfaces, and the results were compared with the analogous thiol–ene click (TEC) chemistry. A wide range of thiols such as 9-fluorenylmethoxy-carbon

  18. Concentration levels and source apportionment of ultrafine particles in road microenvironments (United States)

    Argyropoulos, G.; Samara, C.; Voutsa, D.; Kouras, A.; Manoli, E.; Voliotis, A.; Tsakis, A.; Chasapidis, L.; Konstandopoulos, A.; Eleftheriadis, K.


    A mobile laboratory unit (MOBILAB) with on-board instrumentation (Scanning Mobility Particle Sizer, SMPS; Ambient NOx analyzer) was used to measure size-resolved particle number concentrations (PNCs) of quasi-ultrafine particles (UFPs, 9-372 nm), along with NOx, in road microenvironments. On-road measurements were carried out in and around a large Greek urban agglomeration, the Thessaloniki Metropolitan Area (TMA). Two 2-week measurement campaigns were conducted during the warm period of 2011 and the cold period of 2012. During each sampling campaign, MOBILAB was driven through a 5-day inner-city route and a second 5-day external route covering in total a wide range of districts (urban, urban background, industrial and residential), and road types (major and minor urban roads, freeways, arterial and interurban roads). All routes were conducted during working days, in morning and in afternoon hours under real-world traffic conditions. Spatial classification of MOBILAB measurements involved the assignment of measurement points to location bins defined by the aspect ratio of adjacent urban street canyons (USCs). Source apportionment was further carried out, by applying Positive Matrix Factorization (PMF) to particle size distribution data. Apportioned PMF factors were interpreted, by employing a two-step methodology, which involved (a) statistical association of PMF factor contributions with 12 h air-mass back-trajectories ending at the TMA during MOBILAB measurements, and (b) Multiple Linear Regression (MLR) using PMF factor contributions as the dependent variables, while relative humidity, solar radiation flux, and vehicle speed were used as the independent variables. The applied data analysis showed that low-speed cruise and high-load engine operation modes are the two dominant sources of UFPs in most of the road microenvironments in the TMA, with significant contributions from background photochemical processes during the warm period, explaining the reversed

  19. "Click"化学在药物发现中的应用%Click chemistry in drug discovery

    Institute of Scientific and Technical Information of China (English)

    仇文卫; 李静雅; 李佳; 南发俊



  20. Modelling street level PM10 concentrations across Europe: source apportionment and possible futures

    Directory of Open Access Journals (Sweden)

    G. Kiesewetter


    Full Text Available Despite increasing emission controls, particulate matter (PM has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter 10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are largely eliminated in a scenario applying the best available emission control technologies to the maximal technically feasible extent.

  1. Modelling street level PM10 concentrations across Europe: source apportionment and possible futures

    Directory of Open Access Journals (Sweden)

    G. Kiesewetter


    Full Text Available Despite increasing emission controls, particulate matter (PM has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter 10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are largely eliminated in a scenario applying the best available emission control technologies to the maximal technically feasible extent.

  2. Click chemistry with polymers, dendrimers, and hydrogels for drug delivery. (United States)

    Lallana, Enrique; Fernandez-Trillo, Francisco; Sousa-Herves, Ana; Riguera, Ricardo; Fernandez-Megia, Eduardo


    During the last decades, great efforts have been devoted to design polymers for reducing the toxicity, increasing the absorption, and improving the release profile of drugs. Advantage has been also taken from the inherent multivalency of polymers and dendrimers for the incorporation of diverse functional molecules of interest in targeting and diagnosis. In addition, polymeric hydrogels with the ability to encapsulate drugs and cells have been developed for drug delivery and tissue engineering applications. In the long road to this successful story, pharmaceutical sciences have been accompanied by parallel advances in synthetic methodologies allowing the preparation of precise polymeric materials with enhanced properties. In this context, the introduction of the click concept by Sharpless and coworkers in 2001 focusing the attention on modularity and orthogonality has greatly benefited polymer synthesis, an area where reaction efficiency and product purity are significantly challenged. The purpose of this Expert Review is to discuss the impact of click chemistry in the preparation and functionalization of polymers, dendrimers, and hydrogels of interest in drug delivery.

  3. Glycoprotein labeling with click chemistry (GLCC) and carbohydrate detection. (United States)

    Wu, Zhengliang L; Huang, Xinyi; Burton, Andrew J; Swift, Karl A D


    Molecular labeling and detection techniques are essential to research in life science. Here, a method for glycoprotein labeling/carbohydrate detection through glycan replacement, termed glycoprotein labeling with click chemistry (GLCC), is described. In this method, a glycoprotein is first treated with specific glycosidases to remove certain sugar residues, a procedure that creates acceptor sites for a specific glycosyltransferase. A 'clickable' monosaccharide is then installed onto these sites by the glycosyltransferase. This modified glycoprotein is then conjugated to a reporter molecule using a click chemistry reaction. For glycoproteins that already contain vacant glycosylation sites, deglycosylation is not needed before the labeling step. As a demonstration, labeling on fetal bovine fetuin, mouse immunoglobulin IgG and bacterial expressed human TNFα and TNFβ are shown. Compared to traditional ways of protein labeling, labeling at glycosylation sites with GLCC is considerably more specific and less likely to have adverse effects, and, when utilized as a method for carbohydrate detection, this method is also highly specific and sensitive.

  4. Grafting of Polycaprolactone on Oxidized Nanocelluloses by Click Chemistry

    Directory of Open Access Journals (Sweden)

    Claude Daneault


    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.

  5. Binding-regulated click ligation for selective detection of proteins. (United States)

    Cao, Ya; Han, Peng; Wang, Zhuxin; Chen, Weiwei; Shu, Yongqian; Xiang, Yang


    Herein, a binding-regulated click ligation (BRCL) strategy for endowing selective detection of proteins is developed with the incorporation of small-molecule ligand and clickable DNA probes. The fundamental principle underlying the strategy is the regulating capability of specific protein-ligand binding against the ligation between clickable DNA probes, which could efficiently combine the detection of particular protein with enormous DNA-based sensing technologies. In this work, the feasibly of the BRCL strategy is first verified through agarose gel electrophoresis and electrochemical impedance spectroscopy measurements, and then confirmed by transferring it to a nanomaterial-assisted fluorescence assay. Significantly, the BRCL strategy-based assay is able to respond to target protein with desirable selectivity, attributing to the specific recognition between small-molecule ligand and its target. Further experiments validate the general applicability of the sensing method by tailoring the ligand toward different proteins (i.e., avidin and folate receptor), and demonstrate its usability in complex biological samples. To our knowledge, this work pioneers the practice of click chemistry in probing specific small-molecule ligand-protein binding, and therefore may pave a new way for selective detection of proteins.

  6. 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;


    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......-second average at its output, while simultaneously achieving inductive voltage boosting by shooting through either an appropriately selected inverter phase-leg or two phase-legs being commanded simultaneously. More interestingly, these performance features are achieved with no increase in the number...

  7. Sources of Career Dissatisfaction among Mid-Level Coast Guard Officers. (United States)


    1967. 92 i ’ - - - - i dlMMfc i<iMMM|MiM(^aMt)|| | r^ -»—^»» •• i P • . I Vroom , Victor H ., Work and Motivation, New York...Austin: Business Publications, Inc. 1971. 18 i— I In 1965 Vroom introduced his theory of work motivation. This theory became the foundation for...level outcomes or valued rewards [ Vroom , 1964]. Lawler and Porter [1967] added further modification factors to Vroom’s model. Their study examined

  8. Elevated Blood Lead Levels in Infants and Mothers in Benin and Potential Sources of Exposure. (United States)

    Bodeau-Livinec, Florence; Glorennec, Philippe; Cot, Michel; Dumas, Pierre; Durand, Séverine; Massougbodji, Achille; Ayotte, Pierre; Le Bot, Barbara


    Lead in childhood is well known to be associated with poor neurodevelopment. As part of a study on maternal anemia and offspring neurodevelopment, we analyzed blood lead level (BLL) with no prior knowledge of lead exposure in 225 mothers and 685 offspring 1 to 2 years old from Allada, a semi-rural area in Benin, sub-Saharan Africa, between May 2011 and May 2013. Blood samples were analyzed by inductively coupled plasma mass spectrometry. Environmental assessments in households and isotopic ratio measurements were performed for eight children with BLL > 100 µg/L. High lead levels (BLL > 50 µg/L) were found in 44% of mothers and 58% of children. The median BLL was 55.1 (interquartile range 39.2-85.0) and 46.6 (36.5-60.1) µg/L, respectively. Maternal BLL was associated with offspring's consumption of piped water and animals killed by ammunition. Children's BLL was associated with presence of paint chips in the house and consumption of animals killed by ammunition. In this population, with 98% of children still breastfed, children's BLL was highly associated with maternal BLL on multivariate analyses. Environmental measures and isotopic ratios supported these findings. Offspring may be highly exposed to lead in utero and probably via breastfeeding in addition to lead paint exposure.

  9. Shielding NSLS-II light source: Importance of geometry for calculating radiation levels from beam losses (United States)

    Kramer, S. L.; Ghosh, V. J.; Breitfeller, M.; Wahl, W.


    Third generation high brightness light sources are designed to have low emittance and high current beams, which contribute to higher beam loss rates that will be compensated by Top-Off injection. Shielding for these higher loss rates will be critical to protect the projected higher occupancy factors for the users. Top-Off injection requires a full energy injector, which will demand greater consideration of the potential abnormal beam miss-steering and localized losses that could occur. The high energy electron injection beam produces significantly higher neutron component dose to the experimental floor than a lower energy beam injection and ramped operations. Minimizing this dose will require adequate knowledge of where the miss-steered beam can occur and sufficient EM shielding close to the loss point, in order to attenuate the energy of the particles in the EM shower below the neutron production threshold (energy on the bulk shield walls and thereby the dose penetrating the shield walls. Designing supplemental shielding near the loss point using the analytic shielding model is shown to be inadequate because of its lack of geometry specification for the EM shower process. To predict the dose rates outside the tunnel requires detailed description of the geometry and materials that the beam losses will encounter inside the tunnel. Modern radiation shielding Monte-Carlo codes, like FLUKA, can handle this geometric description of the radiation transport process in sufficient detail, allowing accurate predictions of the dose rates expected and the ability to show weaknesses in the design before a high radiation incident occurs. The effort required to adequately define the accelerator geometry for these codes has been greatly reduced with the implementation of the graphical interface of FLAIR to FLUKA. This made the effective shielding process for NSLS-II quite accurate and reliable. The principles used to provide supplemental shielding to the NSLS-II accelerators and

  10. Constrained Maximum Likelihood Estimation for Model Calibration Using Summary-level Information from External Big Data Sources. (United States)

    Chatterjee, Nilanjan; Chen, Yi-Hau; Maas, Paige; Carroll, Raymond J


    Information from various public and private data sources of extremely large sample sizes are now increasingly available for research purposes. Statistical methods are needed for utilizing information from such big data sources while analyzing data from individual studies that may collect more detailed information required for addressing specific hypotheses of interest. In this article, we consider the problem of building regression models based on individual-level data from an "internal" study while utilizing summary-level information, such as information on parameters for reduced models, from an "external" big data source. We identify a set of very general constraints that link internal and external models. These constraints are used to develop a framework for semiparametric maximum likelihood inference that allows the distribution of covariates to be estimated using either the internal sample or an external reference sample. We develop extensions for handling complex stratified sampling designs, such as case-control sampling, for the internal study. Asymptotic theory and variance estimators are developed for each case. We use simulation studies and a real data application to assess the performance of the proposed methods in contrast to the generalized regression (GR) calibration methodology that is popular in the sample survey literature.

  11. The inverse electron demand Diels-Alder click reaction in radiochemistry. (United States)

    Reiner, Thomas; Zeglis, Brian M


    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.

  12. SYNMAG Photometry: A Fast Tool for Catalog-Level Matched Colors of Extended Sources

    CERN Document Server

    Bundy, Kevin; Higgs, Tim D; Nichol, Robert C; Yasuda, Naoki; Masters, Karen L; Lang, Dustin; Wake, David A


    Obtaining reliable, matched photometry for galaxies imaged by different observatories represents a key challenge in the era of wide-field surveys spanning more than several hundred square degrees. Methods such as flux fitting, profile fitting, and PSF homogenization followed by matched-aperture photometry are all computationally expensive. We present an alternative solution called "synthetic aperture photometry" that exploits galaxy profile fits in one band to efficiently model the observed, PSF-convolved light profile in other bands and predict the flux in arbitrarily sized apertures. Because aperture magnitudes are the most widely tabulated flux measurements in survey catalogs, producing synthetic aperture magnitudes (SYNMAGs) enables very fast matched photometry at the catalog level, without reprocessing imaging data. We make our code public and apply it to obtain matched photometry between SDSS ugriz and UKIDSS YJHK imaging, recovering red-sequence colors and photometric redshifts with a scatter and accur...

  13. Effect of Different Nitrogen Sources and Levels on Quantitative and Qualitative Characteristics of Parsley (Petroselinum crispum Mill. in Jiroft Region

    Directory of Open Access Journals (Sweden)

    hosein Saidi Goraghani


    Full Text Available Parsley has a very high nutritional value, containing A, B and C vitamins and mineral nutrients. In order to investigation of the effect of different nitrogen sources on parsley an experiment conducted in a factorial combination of three nitrogen forms (calcium nitrate, ammonium sulphate and urea and four nitrogen levels (0, 100, 125, 150 kg ha-1 by using a factorial experiment based on randomized complete block design with three replications. The results showed that the effect of nitrogen sources was significant on all measured parameters. As the highest shoot fresh weight, root fresh weight, vitamin C and leaf Ca concentration obtained at 150 kg ha-1 of calcium nitrate and the highest shoot dry weight, plant height, leaf length and leaf iron concentration at 150 kg ha-1 of ammonium sulphate and the highest amount of chlorophyll a+b at 150 kg ha-1 of urea.

  14. Use of the Drawing-Writing Technique to Determine the Level of Knowledge of Pre-Service Teachers Regarding Renewable Energy Sources (United States)

    Kara, Filiz


    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…

  15. Source terms for radioactive gaseous effluents from a model high-level waste solidification facility

    Energy Technology Data Exchange (ETDEWEB)

    Godbee, H.W.; Kibbey, A.H.


    The model high-level waste solidification facility (WSF) is envisaged as being similar to the New Waste Calcining Facility (NWCF) being constructed at the Idaho National Engineering Laboratory but with provisions for incorporating the calcine into a glass. The decontamination factor (DF) is estimated to be one for tritium, 100 for iodine, and 5.0 x 10/sup 8/ for ruthenium. The DFs for other nuclides are in the range of mid to high 10/sup 9/. The volatile radionuclide of primary concern in waste solidification is ruthenium (in particular, /sup 106/Ru). With an estimated DF of 5.0 x 10/sup 8/, the /sup 106/Ru expected to be released from the WSF amounts to 3.4, 2.9, and 0.091 mCi/day for immediate solidification, a freshly filled waste tank (189 days), and five years of tank storage, respectively. The FSAR of the Barnwell Nuclear Fuel Plant Separations Facility implies that 4.6 mCi/day of /sup 106/Ru might be released from the stack of the separations facility and states that such a release meets all state and Federal standards and specifications.

  16. Power Quality Improvement at Distribution Level for Grid Connected Renewable Energy Sources

    Directory of Open Access Journals (Sweden)

    S. Syed Ahmed


    Full Text Available The non-linear load current harmonics may result in voltage harmonics and can create a serious PQ problem in the power system network. Active power filters (APF are extensively used to compensate the load current harmonics and load unbalance at distribution level. This results in an additional hardware cost. However, in this project it has incorporated the features of APF in the conventional inverter interfacing renewable with the grid, without any additional hardware cost. Here, the main idea is the maximum utilization of inverter rating which is most of the time underutilized due to intermittent nature of RES. The grid-interfacing inverter can effectively be utilized to perform the four important functions they are to transfer active power harvested from the renewable resources (wind, solar, etc., load reactive power demand support, current harmonics compensation at PCC and current unbalance and neutral current compensation in case of 3-phase 4-wire system. Moreover, with adequate control of grid-interfacing inverter, all the four objectives can be accomplished either individually or simultaneously. The PQ constraints at the PCC can therefore be strictly maintained within the utility standards without additional hardware cost. With such a control, the combination of grid-interfacing inverter and the 3-phase 4-wire linear/non-linear unbalanced load at point of common coupling appears as balanced linear load to the grid. This new control concept is demonstrated with extensive MATLAB/Simulink simulation studies

  17. Plasma lipid levels of rats fed a diet containing pork fat as a source of lipids after splenic surgery. (United States)

    Dinis, Ana Paula Gonçalves; Marques, Ruy Garcia; Simões, Fernanda Correia; Diestel, Cristina Fajardo; Caetano, Carlos Eduardo Rodrigues; Secchin, Dióscuro José Ferreira; Neto, José Firmino Nogueira; Portela, Margareth Crisóstomo


    Experimental studies have suggested an important role of the spleen in lipid metabolism, although with controversial results. Our purpose was to analyze the effect of a nutritionally balanced (NB) diet and a diet containing pork fat (PF) as source of lipids on the lipid profile of rats submitted to splenic surgery. Sixty adult male Wistar rats were divided into six groups of 10 animals each: 1 sham-operated, NB diet; 2 sham-operated, PF diet; 3 total splenectomy (TS), NB diet; 4 TS, PF diet; 5 TS followed by splenic autotransplantation (SA), NB diet; and 6 SA, PF diet. Blood samples were collected at the beginning (D0) and after 12 weeks of the experiment (D + 12) for plasma lipid determination. Morphologic regeneration of splenic tissues was observed, with no differences between groups 5 and 6. When D + 12 plasma lipid levels were compared to D0 levels there were no differences in groups 1, 3, and 5, while in groups 2, 4, and 6 total cholesterol (TC), low density lipoprotein (LDL), very low density lipoprotein (VLDL), and triacylglycerols (TAG) increased, and high density lipoprotein (HDL) decreased. At D + 12, groups 2, 4, and 6 had lower HDL than group 3. In conclusion, regardless of the surgical procedure applied to the spleen, an NB diet maintained plasma lipid levels while a diet with PF as source of lipids changed the animals' lipid profile.

  18. Ten Click Rule: A Test of the Effectiveness of a New Rule for Simplifying Battle Field Sight Adjustment (United States)


    representing one click of the sight (a click is equal to one minute of angle). Diagrams at the margins of the grid * . show which sight to change and all ranges, i.e. a minute of angle is equal to two inches as 200 yards. Third, one click on the M16 is equal to one minute of angle. One heuristic...10-click rule. Only one of the 12 subjects questioned missed the exact sight change on the paper task by more than one click . This ensured that

  19. Perfluorinated Compounds in Greenhouse and Open Agricultural Producing Areas of Three Provinces of China: Levels, Sources and Risk Assessment

    Directory of Open Access Journals (Sweden)

    Yanwei Zhang


    Full Text Available Field investigations on perfluoroalkyl acid (PFAA levels in various environmental matrixes were reported, but there is still a lack of PFAA level data for agricultural environments, especially agricultural producing areas, so we collected soil, irrigation water and agricultural product samples from agricultural producing areas in the provinces of Liaoning, Shandong and Sichuan in China. The background pollution from instruments was removed and C4–C18 PFAAs were detected by LC-MS/MS. The concentrations of PFAAs in the top and deep layers of soil were compared, and the levels of PFAAs in different agricultural environments (greenhouses and open agriculture were analyzed. We found the order of PFAA levels by province was Shandong > Liaoning > Sichuan. A descending trend of PFAA levels from top to deep soil and open to greenhouse agriculture was shown and perfluorobutanoic acid (PFBA was considered as a marker for source analysis. Bean vegetables contribute highly to the overall PFAA load in vegetables. A significant correlation was shown between irrigation water and agricultural products. The EDI (estimated daily intake from vegetables should be of concern in China.

  20. Detecting the Sea-Level Fingerprint of Polar Ice Mass Changes: Testing a New Method for Estimating the Sources of Global Sea Level Change (United States)

    Hay, C.; Morrow, E.; Kopp, R. E.; Mitrovica, J. X.


    Twentieth and 21st century rates of globally averaged sea level (SL) change have commonly been estimated using subsets of tide gauge records and satellite altimetry data. However, these estimates ignore the information embedded in the geographic variability of the measurements. It is now well known, for example, that the rapid melting of an individual ice sheet or glacier will produce a unique geometry, or fingerprint, of SL change. In principle, a suite of such fingerprints, together with a network of modern SL observations with sufficient geographic distribution and signal-to-noise properties, may be used to infer recent sources of meltwater flux. We outline a new formalism based on a Kalman filter for estimating the individual SL contributions to global SL change using tide gauge and satellite altimetry measurements. The Kalman filter is well-suited to such an estimate because: 1) it naturally accommodates missing data, a significant factor for sparse sections of the tide gauge record; 2) it is able to optimally estimate non-stationary trends and the associated uncertainty; and 3) its recursive nature reduces the potentially onerous computational memory requirements caused by large volumes of tide gauge or satellite altimetry data. We first explore the feasibility of extracting source information from SL records by applying the new methodology in a series of detection experiments with synthetic tide gauge and altimetry data sets. Our synthetic data sets are constructed by combining de-trended tide gauge or satellite altimetry records with sea-level fingerprints computed for a variety of Greenland Ice Sheet (GIS) and West Antarctic Ice Sheet (WAIS) melt scenarios. Additional contributions to SL change, such as the signal due to on-going glacial isostatic adjustment in response to the last ice age and dynamic sea level changes due to thermal expansion of the ocean are also included in the synthetics. We apply our modified Kalman filter to various subsets of

  1. Assessing segmentation processes by click detection: online measure of statistical learning, or simple interference? (United States)

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


    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.

  2. Supporting the Cybercrime Investigation Process: Effective Discrimination of Source Code Authors Based on Byte-Level Information (United States)

    Frantzeskou, Georgia; Stamatatos, Efstathios; Gritzalis, Stefanos

    Source code authorship analysis is the particular field that attempts to identify the author of a computer program by treating each program as a linguistically analyzable entity. This is usually based on other undisputed program samples from the same author. There are several cases where the application of such a method could be of a major benefit, such as tracing the source of code left in the system after a cyber attack, authorship disputes, proof of authorship in court, etc. In this paper, we present our approach which is based on byte-level n-gram profiles and is an extension of a method that has been successfully applied to natural language text authorship attribution. We propose a simplified profile and a new similarity measure which is less complicated than the algorithm followed in text authorship attribution and it seems more suitable for source code identification since is better able to deal with very small training sets. Experiments were performed on two different data sets, one with programs written in C++ and the second with programs written in Java. Unlike the traditional language-dependent metrics used by previous studies, our approach can be applied to any programming language with no additional cost. The presented accuracy rates are much better than the best reported results for the same data sets.

  3. Click Chemistry Immobilization of Antibodies on Polymer Coated Gold Nanoparticles. (United States)

    Finetti, Chiara; Sola, Laura; Pezzullo, Margherita; Prosperi, Davide; Colombo, Miriam; Riva, Benedetta; Avvakumova, Svetlana; Morasso, Carlo; Picciolini, Silvia; Chiari, Marcella


    The goal of this work is to develop an innovative approach for the coating of gold nanoparticles (AuNPs) with a synthetic functional copolymer. This stable coating with a thickness of few nanometers provides, at the same time, stabilization and functionalization of the particles. The polymeric coating consists of a backbone of polydimethylacrylamide (DMA) functionalized with an alkyne monomer that allows the binding of azido modified molecules by Cu(I)-catalyzed azide/alkyne 1,3-dipolar cycloaddition (CuAAC, click chemistry). The thin polymer layer on the surface stabilizes the colloidal suspension whereas the alkyne functions pending from the backbone are available for the reaction with azido-modified proteins. The reactivity of the coating is demonstrated by immobilizing an azido modified anti-mouse IgG antibody on the particle surface. This approach for the covalent binding of antibody to a gold-NPs is applied to the development of gold labels in biosensing techniques.

  4. Efficient One-click Browsing of Large Trajectory Sets

    DEFF Research Database (Denmark)

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


    Traffic researchers, planners, and analysts want a simple way to query the large quantities of GPS trajectories collected from vehicles. In addition, users expect the results to be presented immediately even when querying very large transportation networks with huge trajectory data sets. This paper...... 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...

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

    Directory of Open Access Journals (Sweden)

    Yinliang Yang


    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. In Situ Click Chemistry for the Identification of a Potent D-Amino Acid Oxidase Inhibitor. (United States)

    Toguchi, Shohei; Hirose, Tomoyasu; Yorita, Kazuko; Fukui, Kiyoshi; Sharpless, K Barry; Ōmura, Satoshi; Sunazuka, Toshiaki


    In situ click chemistry is a target-guided synthesis approach for discovering novel lead compounds by assembling organic azides and alkynes into triazoles inside the affinity site of target biogenic molecules such as proteins. We report in situ click chemistry screening with human D-amino acid oxidase (hDAO), which led to the identification of a more potent hDAO inhibitor. The hDAO inhibitors have chemotherapeutic potential as antipsychotic agents. The new inhibitor displayed competitive inhibition of hDAO and showed significantly increased inhibitory activity against hDAO compared with that of an anchor molecule of in situ click chemistry.

  7. Harmonic allocation of authorship credit: source-level correction of bibliometric bias assures accurate publication and citation analysis.

    Directory of Open Access Journals (Sweden)

    Nils T Hagen

    Full Text Available Authorship credit for multi-authored scientific publications is routinely allocated either by issuing full publication credit repeatedly to all coauthors, or by dividing one credit equally among all coauthors. The ensuing inflationary and equalizing biases distort derived bibliometric measures of merit by systematically benefiting secondary authors at the expense of primary authors. Here I show how harmonic counting, which allocates credit according to authorship rank and the number of coauthors, provides simultaneous source-level correction for both biases as well as accommodating further decoding of byline information. I also demonstrate large and erratic effects of counting bias on the original h-index, and show how the harmonic version of the h-index provides unbiased bibliometric ranking of scientific merit while retaining the original's essential simplicity, transparency and intended fairness. Harmonic decoding of byline information resolves the conundrum of authorship credit allocation by providing a simple recipe for source-level correction of inflationary and equalizing bias. Harmonic counting could also offer unrivalled accuracy in automated assessments of scientific productivity, impact and achievement.

  8. Comparison of laser and diode sources for acceleration of in vitro wound healing by low-level light therapy. (United States)

    Spitler, Ryan; Berns, Michael W


    Low-level light therapy has been shown to improve in vitro wound healing. However, well-defined parameters of different light sources for this therapy are lacking. The goal of this study was (1) to determine if the wavelengths tested are effective for in vitro wound healing and (2) to compare a laser and a light-emitting diode (LED) source at similar wavelengths. We show four wavelengths, delivered by either a laser or LED array, improved in vitro wound healing in A549, U2OS, and PtK2 cells. Improved wound healing occurred through increased cell migration demonstrated through scratch wound and transwell assays. Cell proliferation was tested by the (3-(4,5-dimethylthiazol-2-yl)-5-(3-car-boxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assay and was found generally not to be involved in the wound healing process. The laser and LED sources were found to be comparable when equal doses of light were applied. The biological response measured was similar in most cases. We conclude that the laser at 652 (5.57  mW/cm2, 10.02  J/cm2) and 806 nm (1.30  mW/cm2, 2.334  J/cm2) (full bandwidth 5 nm), and LED at 637 (5.57  mW/cm2, 10.02  J/cm2) and 901 nm (1.30  mW/cm2, 2.334  J/cm2) (full bandwidth 17 and 69 nm respectively) induce comparable levels of cell migration and wound closure.

  9. Impact of external industrial sources on the regional and local SO2 and O3 levels of the Mexico megacity (United States)

    Almanza, V. H.; Molina, L. T.; Li, G.; Fast, J.; Sosa, G.


    The air quality of megacities can be influenced by external emission sources on both global and regional scales. At the same time their outflow emissions can exert an impact to the surrounding environment. The present study evaluates an SO2 peak observed on 24 March 2006 at the suburban supersite T1 and at ambient air quality monitoring stations located in the northern region of the Mexico City Metropolitan Area (MCMA) during the Megacity Initiative: Local and Global Research Observations (MILAGRO) field campaign. We found that this peak could be related to an important episodic emission event coming from Tizayuca region, northeast of the MCMA. Back-trajectory analyses suggest that the emission event started in the early morning at 04:00 LST and lasted for about 9 h. The estimated emission rate is about 2 kg s-1. To the best of our knowledge, sulfur dioxide emissions from the Tizayuca region have not been considered in previous studies. This finding suggests the possibility of "overlooked" emission sources in this region that could influence the air quality of the MCMA. This further motivated us to study the cement plants, including those in the state of Hidalgo and in the State of Mexico. It was found that they can contribute to the SO2 levels in the northeast (NE) region of the basin (about 42%), at the suburban supersite T1 (41%) and that at some monitoring stations their contribution can be even higher than the contribution from the Tula Industrial Complex (TIC). The contribution of the Tula Industrial Complex to regional ozone levels is estimated. The model suggests low contribution to the MCMA (1 to 4 ppb) and slightly higher contribution at the suburban T1 (6 ppb) and rural T2 (5 ppb) supersites. However, the contribution could be as high as 10 ppb in the upper northwest region of the basin and in the southwest and south-southeast regions of the state of Hidalgo. In addition, the results indicated that the ozone plume could also be transported to northwest

  10. Sources of signal in 62 protein-coding nuclear genes for higher-level phylogenetics of arthropods.

    Directory of Open Access Journals (Sweden)

    Jerome C Regier

    Full Text Available BACKGROUND: This study aims to investigate the strength of various sources of phylogenetic information that led to recent seemingly robust conclusions about higher-level arthropod phylogeny and to assess the role of excluding or downweighting synonymous change for arriving at those conclusions. METHODOLOGY/PRINCIPAL FINDINGS: The current study analyzes DNA sequences from 68 gene segments of 62 distinct protein-coding nuclear genes for 80 species. Gene segments analyzed individually support numerous nodes recovered in combined-gene analyses, but few of the higher-level nodes of greatest current interest. However, neither is there support for conflicting alternatives to these higher-level nodes. Gene segments with higher rates of nonsynonymous change tend to be more informative overall, but those with lower rates tend to provide stronger support for deeper nodes. Higher-level nodes with bootstrap values in the 80% - 99% range for the complete data matrix are markedly more sensitive to substantial drops in their bootstrap percentages after character subsampling than those with 100% bootstrap, suggesting that these nodes are likely not to have been strongly supported with many fewer data than in the full matrix. Data set partitioning of total data by (mostly synonymous and (mostly nonsynonymous change improves overall node support, but the result remains much inferior to analysis of (unpartitioned nonsynonymous change alone. Clusters of genes with similar nonsynonymous rate properties (e.g., faster vs. slower show some distinct patterns of node support but few conflicts. Synonymous change is shown to contribute little, if any, phylogenetic signal to the support of higher-level nodes, but it does contribute nonphylogenetic signal, probably through its underlying heterogeneous nucleotide composition. Analysis of seemingly conservative indels does not prove useful. CONCLUSIONS: Generating a robust molecular higher-level phylogeny of Arthropoda is

  11. Impact of external industrial sources on the regional and local SO₂ and O₃ levels of the Mexico megacity

    Energy Technology Data Exchange (ETDEWEB)

    Almanza, V. H.; Molina, Luisa T.; Li, Guohui; Fast, Jerome D.; Sosa, G.


    The air quality of megacities can be influenced by external emissions sources on both global and regional scale, and at the same time their outflow emissions can exert an important impact to the surrounding environment. The present study evaluates an SO₂ peak observed on 24 March 2006 at the suburban supersite T1 and ambient air quality monitoring stations located in the north region of the Mexico City Metropolitan Area (MCMA) during MILAGRO campaign. We found that this peak could be related to an important episodic emission event from Tizayuca region, northeast of the MCMA. Back trajectories analyses suggest that the emission event started in the early morning at 10 04:00 LST and lasted for about 9 h. The estimated emission rate is noticeably high, about 2 kgs-¹. This finding suggests the possibility of "overlooked"emission sources in this region that could influence the air quality of the MCMA. This further motivated us to study the cement plants, including those in the State of Hidalgo and in the State of Mexico, and we found that they can contribute in the NE region of the basin (about 15 41.7%), at the suburban supersite T1 (41.23%) and at some monitoring stations their contribution can be even higher than from the Tula Industrial Complex. The contribution of Tula Industrial Complex to regional ozone levels is estimated. The model suggests low contribution to the MCMA (1 ppb to 4 ppb) and slightly higher at the suburban T1 (6 ppb) and rural T2 (5 ppb) supersites. However, the contribution could be 20 as high as 10 ppb in the upper northwest region of the basin and in the southwest and south-southeast regions of State of Hidalgo. In addition, a first estimate of the potential contribution from flaring activities to regional ozone levels is presented. Emission rates are estimated with a CFD combustion model. Results suggest that up to 30% of the total regional ozone from TIC could be related to flaring activities. 25 Finally, the influence in SO₂ levels

  12. 129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement (United States)

    Liu, Dan; Hou, Xiaolin; Du, Jinzhou; Zhang, Luyuan; Zhou, Weijian


    Anthropogenic 129I as a long-lived radioisotope of iodine has been considered as an ideal oceanographic tracer due to its high residence time and conservative property in the ocean. Surface water samples collected from the East China Sea (ECS) in August 2013 were analyzed for 129I, 127I and their inorganic chemical species in the first time. The measured 129I/127I ratio is 1-3 orders of magnitude higher than the pre-nuclear level, indicating its dominantly anthropogenic sources. Relatively high 129I levels were observed in the Yangtze River and its estuary, as well as in the southern Yellow Sea, and 129I level in seawater declines towards the ECS shelf. In the open sea, 129I and 127I in surface water exists mainly as iodate, while in Yangtze River estuary and some locations, iodide is dominated. The results indicate that the Fukushima nuclear accident has no detectable effects in the ECS until August 2013. The obtained results are used for investigation of interaction of various water masses and water circulation in the ECS, as well as the marine environment in this region. Meanwhile this work provides essential data for evaluation of the possible influence of the increasing NPPs along the coast of the ECS in the future.

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

    Directory of Open Access Journals (Sweden)

    Thomas L. Mindt


    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.

  14. Click-MS: Tagless Protein Enrichment Using Bioorthogonal Chemistry for Quantitative Proteomics. (United States)

    Smits, Arne H; Borrmann, Annika; Roosjen, Mark; van Hest, Jan C M; Vermeulen, Michiel


    Epitope-tagging is an effective tool to facilitate protein enrichment from crude cell extracts. Traditionally, N- or C-terminal fused tags are employed, which, however, can perturb protein function. Unnatural amino acids (UAAs) harboring small reactive handles can be site-specifically incorporated into proteins, thus serving as a potential alternative for conventional protein tags. Here, we introduce Click-MS, which combines the power of site-specific UAA incorporation, bioorthogonal chemistry, and quantitative mass spectrometry-based proteomics to specifically enrich a single protein of interest from crude mammalian cell extracts. By genetic encoding of p-azido-l-phenylalanine, the protein of interest can be selectively captured using copper-free click chemistry. We use Click-MS to enrich proteins that function in different cellular compartments, and we identify protein-protein interactions, showing the great potential of Click-MS for interaction proteomics workflows.

  15. Click chemistry patents and their impact on drug discovery and chemical biology. (United States)

    Xu, Hua; Jones, Lyn H


    First introduced by K Barry Sharpless in 2001, the term 'click chemistry' soon became a widely used description of chemical reactions that proceed rapidly, cleanly and in a manner that is often compatible with aqueous solutions. Click chemistry is frequently employed throughout the process of drug discovery, and greatly helps advance research programs in the pharmaceutical industry. It facilitates library synthesis to support medicinal chemistry optimization, helps identify the targets and off-targets of drug candidates, and can facilitate the determination of drug efficacy in clinical trials. In the last decade, a large number of patent applications covering the various types and utilities of click chemistry have been filed. In this review, we provide the first analysis of click chemistry applications.

  16. 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;


    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...

  17. Response of the modern lactating sow and progeny to source and level of supplemental dietary fat during high ambient temperatures. (United States)

    Rosero, D S; van Heugten, E; Odle, J; Arellano, C; Boyd, R D


    The objective of this study was to determine the response to increments of 2 sources of dietary fat on lactating sow and progeny performance during high ambient temperatures. Data were collected from 391 sows (PIC Camborough) from June to September in a 2,600-sow commercial unit in Oklahoma. Sows were randomly assigned to a 2 × 3 factorial arrangement of treatments and a control diet. Factors included 1) fat sources, animal-vegetable blend (A-V) and choice white grease (CWG), and 2) fat levels (2%, 4%, and 6%). The A-V blend contained 14.5% FFA with an iodine value of 89, peroxide value of 4.2 mEq/kg, and anisidine value of 23, whereas CWG contained 3.7% FFA with an iodine value of 62, peroxide value of 9.8 mEq/kg, and anisidine value of 5. Diets were corn-soybean meal based, with 8.0% distillers dried grains with solubles and 6.0% wheat middlings, and contained 3.56-g standardized ileal digestible Lys/Mcal ME. Sows were balanced by parity, with 192 and 199 sows representing parity 1 and parity 3 to 5, respectively. Feed refusal increased linearly (P feed and energy intake increased linearly (P Sows fed CWG diets had reduced (linear, P sow and litter gain relative to feed intake) compared with the G:F of sows fed the control diet or the diets containing the A-V blend (0.50, 0.43, and 0.44, respectively; P feed efficiency than CWG. Subsequent litter size and reproductive performance was improved by inclusion of both sources of fat in diets fed to lactating sows.

  18. Levels and congener specific profiles of PBDEs in human breast milk from China: implication on exposure sources and pathways. (United States)

    Sudaryanto, Agus; Kajiwara, Natsuko; Tsydenova, Oyuna V; Isobe, Tomohiko; Yu, Hongxia; Takahashi, Shin; Tanabe, Shinsuke


    Fourteen PBDE congeners from mono- to deca-BDE were determined in breast milk of primiparous mothers from two locations in East China, i.e. Nanjing (n=9), an urban area, and Zhoushan (n=10), a semi rural coastal area. PBDEs were detected in all the human breast milk samples of the present study, indicating that general population in these two locations are widely exposed to these pollutants. Relatively higher concentrations of PBDEs were found in the milk of mothers from Nanjing than Zhoushan, suggesting the existence of significant sources of PBDEs in urban areas. PBDE levels in the present study were similar to those in European countries, but one or two orders of magnitude lower than in North America. Except for BDE-3, all congeners from di- to deca-BDE were detected in the samples of the present study. BDE-209, a congener considered to have less bioavailability, was detected in about 50% of the samples at concentrations higher than that of other congeners. Other higher brominated congeners, such as BDE-153, -197 and -207, were also prominent in the present study, which is different from the pattern generally observed in previous studies on human milk as well as biota samples. These results may indicate that the inhabitants of Nanjing and Zhoushan are exposed to location specific sources of PBDEs.

  19. Organic maturation levels, thermal history and hydrocarbon source rock potential of the Namurian rocks of the Clare Basin, Ireland

    Energy Technology Data Exchange (ETDEWEB)

    Goodhue, Robbie; Clayton, Geoffrey [Trinity Coll., Dept. of Geology, Dublin (Ireland)


    Vitrinite reflectance data from two inland cored boreholes confirm high maturation levels throughout the onshore part of the Irish Clare Basin and suggest erosion of 2 to 4 km of late Carboniferous cover and elevated palaeogeothermal gradients in the Carboniferous section. The observed maturation gradients are fully consistent with the published hypothesis of a late Carboniferous/Permian 'superplume' beneath Pangaea but local vertical reversals in gradients also suggest a complex thermal regime probably involving advective heating. The uppermost Visean--lower Namurian Clare Shale is laterally extensive and up to 300 m thick. Although this unit is post-mature, TOC values of up to 15% suggest that it could have considerable hydrocarbon source rock potential in any less mature offshore parts of the basin. (Author)

  20. Modelling and control of a seven level NPC voltage source inverter. Application to high power induction machine drive

    Energy Technology Data Exchange (ETDEWEB)

    Gheraia, H.; Berkouk, E.M. [ENP, Alger (Algeria). Lab. de Commande des Processus; Manesse, G. [CNAM-Paris (France). Lab. d' Electricite Industrielle


    In this paper, we study a new kind of continuous-alternating converters: a seven-level neutral point clamping (NPC) voltage source inverter (VSI). We propose this inverter for applications in high voltage and high power fields. In the first part, we develop the knowledge and the control models of this inverter using the connections functions of the semi-conductors. After that, we present two pulse width modulation (PWM) algorithms to control this converter using its control model. We propose these algorithms for digital implementation. This multilevel inverter is associated to the induction machine. The performances obtained are full of promise to use it in the high voltage and high power fields of electrical traction. (orig.)

  1. Growing applications of "click chemistry" for bioconjugation in contemporary biomedical research. (United States)

    Nwe, Kido; Brechbiel, Martin W


    This update summarizes the growing application of "click" chemistry in diverse areas such as bioconjugation, drug discovery, materials science, and radiochemistry. This update also discusses click chemistry reactions that proceed rapidly with high selectivity, specificity, and yield. Two important characteristics make click chemistry so attractive for assembling compounds, reagents, and biomolecules for preclinical and clinical applications. First, click reactions are bio-orthogonal; neither the reactants nor their product's functional groups interact with functionalized biomolecules. Second, the reactions proceed with ease under mild nontoxic conditions, such as at room temperature and, usually, in water. The copper-catalyzed Huisgen cycloaddition, azide-alkyne [3 + 2] dipolar cycloaddition, Staudinger ligation, and azide-phosphine ligation each possess these unique qualities. These reactions can be used to modify one cellular component while leaving others unharmed or untouched. Click chemistry has found increasing applications in all aspects of drug discovery in medicinal chemistry, such as for generating lead compounds through combinatorial methods. Bioconjugation via click chemistry is rigorously employed in proteomics and nucleic research. In radiochemistry, selective radiolabeling of biomolecules in cells and living organisms for imaging and therapy has been realized by this technology. Bifunctional chelating agents for several radionuclides useful for positron emission tomography and single-photon emission computed tomography imaging have also been prepared by using click chemistry. This review concludes that click chemistry is not the perfect conjugation and assembly technology for all applications, but provides a powerful, attractive alternative to conventional chemistry. This chemistry has proven itself to be superior in satisfying many criteria (e.g., biocompatibility, selectivity, yield, stereospecificity, and so forth); thus, one can expect it will

  2. Click-based porous cationic polymers for enhanced carbon dioxide capture


    Dani, Alessandro; Magistris, Valentina Crocella Claudio; Santoro, Valentina; Yuan, Jiayin; Bordiga, Silvia


    Imidazolium based porous cationic polymers were synthesized using an innovative and facile approach, which takes advantage of the Debus Radziszewski reaction to obtain meso- and microporous polymers following click chemistry principles. In the obtained set of materials, click based porous cationic polymers have the same cationic backbone, whereas they bear the commonly used anions of imidazolium poly(ionic liquid)s. These materials show hierarchical porosity and a good specific surface area. ...

  3. Parameterization of the Non-Local Thermodynamic Equilibrium Source Function with Chemical Production by an Equivalent Two-Level Model

    Institute of Scientific and Technical Information of China (English)

    Xun ZHU


    The classic two-level or equivalent two-level model that includes only the statistical equilibriumof radiative and thermal processes of excitation and quenching between two vibrational energy levelsis extended by adding chemical production to the rate equations. The modifications to the non-localthermodynamic equilibrium source function and cooling rate are parameterized by φc, which characterizesthe ratio of chemical production to collisional quenching. For applications of broadband emission of O3 at9.6 μm, the non-LTE effect of chemical production on the cooling rate and limb emission is proportionalto the ratio of O to O3. For a typical [O]/[O3], the maximum enhancements of limb radiance and coolingrate are about 15%-30% and 0.03-0.05 K day-1, respectively, both occurring near the mesopause regions.This suggests that the broadband limb radiance above ~80 km is sensitive to O3 density but not sensitiveto the direct cooling rate along the line-of-sight, which makes O3 retrieval feasible but the direct coolingrate retrieval difficult by using the O3 9.6 μm band limb emission.

  4. 40 CFR Table 3 to Subpart Dd of... - Tank Control Levels for Tanks at Existing Affected Sources as Required by 40 CFR 63.685(b)(1) (United States)


    ... Existing Affected Sources as Required by 40 CFR 63.685(b)(1) 3 Table 3 to Subpart DD of Part 63 Protection... Hazardous Air Pollutants from Off-Site Waste and Recovery Operations Pt. 63, Subpt. DD, Table 3 Table 3 to Subpart DD of Part 63—Tank Control Levels for Tanks at Existing Affected Sources as Required by 40 CFR...

  5. 40 CFR Table 4 to Subpart Dd of... - Tank Control Levels for Tanks at New Affected Sources as Required by 40 CFR 63.685(b)(2) (United States)


    ... Affected Sources as Required by 40 CFR 63.685(b)(2) 4 Table 4 to Subpart DD of Part 63 Protection of... Hazardous Air Pollutants from Off-Site Waste and Recovery Operations Pt. 63, Subpt. DD, Table 4 Table 4 to Subpart DD of Part 63—Tank Control Levels for Tanks at New Affected Sources as Required by 40 CFR...

  6. Effects of different sources and levels of zinc on H2O2-induced apoptosis in IEC-6 cells. (United States)

    Mao, Lei; Chen, Juncai; Peng, Quanhui; Zhou, Aiming; Wang, Zhisheng


    Zinc has been shown to be an inhibitor of apoptosis for many years. The present study was designed to investigate effects of three zinc chemical forms on H2O2-induced cell apoptosis in IEC-6 cells via analysis of cell vitality, LDH activity, apoptosis percentage, caspase-3 activity, and Bcl-2, Bax, and caspase-3, -8, and -9 gene expression. Cells were divided into H2O2 and zinc sources+H2O2 groups, and there are three different zinc sources [zinc oxide nanoparticle (nano-ZnO), zinc oxide (ZnO), and zinc sulfate (ZnSO4)] and three concentrations (normal = 25 μM, medium = 50 μM, and high = 100 μM) used in this article. In the present study, we found the striking cytotoxicity of H2O2 higher than 200 μM on cell vitality, LDH activity, and apoptosis percentage in the cells using five different concentrations (50, 100, 200, 400, and 800 μM) of H2O2 for 4 h. Moreover, we observed that cell vitality was increased, LDH activity and apoptotic percentage were decreased, and gene expression level of Bax and caspase-3 and -9 was markedly reduced, while gene expression level of Bcl-2 and ratio of Bcl-2/Bax were increased in normal concentration groups of nano-ZnO and ZnSO4 compared with H2O2 group, but no significant difference was observed in caspase-8 gene expression. Furthermore, medium or, more intensely, high concentrations of nano-ZnO and ZnSO4 enhanced H2O2-induced cell apoptosis. Compared with nano-ZnO and ZnSO4, ZnO showed weakest protective effect on H2O2-induced apoptosis at normal concentration and was less toxic to cells at high level. Taken together, we proposed that preventive and protective effects of zinc on H2O2-induced cell apoptosis varied in IEC-6 cells with its chemical forms and concentrations, and maybe for the first time, we suggested that nano-ZnO have a protective effect on H2O2-induced cell apoptosis in IEC-6 cells.

  7. Effects of monochromatic light sources on sex hormone levels in serum and on semen quality of ganders. (United States)

    Chang, Shen-Chang; Zhuang, Zi-Xuan; Lin, Min-Jung; Cheng, Chuen-Yu; Lin, Tsung-Yi; Jea, Yu-Shine; Huang, San-Yuan


    Light is an essential external factor influencing various physiological processes, including reproductive performance, in birds. Although several attempts have been made to understand the effect of light on poultry production, the effect of light of a particular wavelength (color) on the reproductive function in geese remains unclear. This study evaluated the effect of various monochromatic light sources on the levels of sex hormone and on semen quality of ganders. Of 30 male White Roman geese in their third reproductive season (average age=3 years), 27 were divided into three groups receiving monochromatic white or red or blue lights. The birds were kept in an environmentally controlled house with a lighting photoperiod of 7L:17D for six weeks as the adaptation period. The photoperiod was subsequently changed to 9L:15D and maintained for 24 weeks. Three ganders at the beginning of the study and three from each group at the end of the adjusting period and the 20th and 30th week of the study period were sacrificed, and their testes and blood samples were collected for determining the sex hormone levels. Semen samples were collected for determining semen quality parameters, including the semen collection index, sperm concentration, semen volume, sperm motility, sperm viability, sperm morphology, and semen quality factor. The results showed that the testosterone and estradiol levels remained unchanged in all three groups at all time points. The ratio of testosterone to estradiol of ganders exposed to white light was significantly higher than that of ganders exposed to red light at the 30th week (Plight were significantly the lowest (Plight were the highest (Plight may maintain a better semen quality than that with red or blue lights in ganders.

  8. Effect of different levels and sources of zinc supplementation on quantitative and qualitative semen attributes and serum testosterone level in crossbred cattle (Bos indicus x Bos taurus) bulls. (United States)

    Kumar, Nishant; Verma, Ramesh Prashad; Singh, Lallan Prasad; Varshney, Vijay Prakash; Dass, Ram Sharan


    An experiment was conducted on 16 crossbred bulls (about 2 years of age, 316.2+/-0.77 kg average body weight), divided into groups I, II, III and IV to study the effect of different levels of Zn supplementation from inorganic and organic sources on semen quality. The animals in the first 3 groups were supplemented with 0, 35 and 70 ppm Zn from Zn sulfate, respectively and the animals in-group IV were supplemented with 35 ppm Zn as Zn propionate. Semen collection and evaluation was done in the first month (to assess semen quality at the start of the experiment) and 7th, 8th and 9th month of experimental feeding to evaluate the effect of supplemental Zn on semen attributes. We gave 6 months for Zn feeding, so that 3 sperm cycles of spermatogenesis had passed and the collected semen reflected the complete effect of Zn supplementation. Six ejaculates from each bull were collected and evaluated for semen quantitative (ejaculate volume, sperm concentration and sperm number per ejaculate) and qualitative characteristics (semen pH, mass motility, individual motility, sperm livability percent and abnormal sperm percent, percent intact acrosome, bovine cervical mucus penetration test, hypo-osmotic sperm swelling test) and activity of seminal plasma enzymes i.e., alkaline phosphatase, acid phosphatase, GOT and GPT. Testosterone level in the blood serum of crossbred bulls was also estimated. Mean values of semen quantitative and qualitative characteristics at the start of the experiment were statistically non significant (P > 0.05) in all the crossbred cattle bulls, however, there were statistically significant differences among the bulls of different groups after 6 months of zinc supplementation. Mean ejaculate volume (mL) was 2.37, 4.70, 5.86 and 6.38, respectively in groups I to IV, indicating a statistically significant (P bulls. Similarly, sperm concentration (million.mL(-1)), live sperm (%) and motility (%) were significantly (P bulls improved the qualitative and

  9. Low level impurities in imported wheat are a likely source of feral transgenic oilseed rape (Brassica napus L.) in Switzerland. (United States)

    Schulze, Juerg; Brodmann, Peter; Oehen, Bernadette; Bagutti, Claudia


    In Switzerland, the cultivation of genetically modified (GM) oilseed rape (Brassica napus L.) and the use of its seeds for food and feed are not permitted. Nevertheless, the GM oilseed rape events GT73, MS8×RF3, MS8 and RF3 have recently been found in the Rhine port of Basel, Switzerland. The sources of GM oilseed rape seeds have been unknown. The main agricultural good being imported at the Rhine port of Basel is wheat and from 2010 to 2013, 19% of all Swiss wheat imports originated from Canada. As over 90% of all oilseed rape grown in Canada is GM, we hypothesised that imports of Canadian wheat may contain low level impurities of GM oilseed rape. Therefore, waste fraction samples gathered during the mechanical cleaning of Canadian wheat from two Swiss grain mills were analysed by separating oilseed rape seeds from waste fraction samples and testing DNA of pooled seeds for the presence of transgenes by real-time PCR. Furthermore, oilseed rape seeds from each grain mill were sown in a germination experiment, and seedling DNA was tested for the presence of transgenes by real-time PCR. GT73, MS8×RF3, MS8 and RF3 oilseed rape was detected among seed samples and seedlings of both grain mills. Based on this data, we projected a mean proportion of 0.005% of oilseed rape in wheat imported from Canada. Besides Canadian wheat, the Rhine port of Basel does not import any other significant amounts of agricultural products from GM oilseed rape producing countries. We therefore conclude that Canadian wheat is the major source of unintended introduction of GM oilseed rape seeds into Switzerland.

  10. Paint and Click: Unified Interactions for Image Boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Summa, B. [Univ. of Utah, Salt Lake City, UT (United States). Scientific Computing and Imaging (SCI) Inst.; Gooch, A. A. [Univ. of Utah, Salt Lake City, UT (United States). Scientific Computing and Imaging (SCI) Inst.; Scorzelli, G. [Univ. of Utah, Salt Lake City, UT (United States). Scientific Computing and Imaging (SCI) Inst.; Pascucci, V. [Univ. of Utah, Salt Lake City, UT (United States). Scientific Computing and Imaging (SCI) Inst.


    Image boundaries are a fundamental component of many interactive digital photography techniques, enabling applications such as segmentation, panoramas, and seamless image composition. Interactions for image boundaries often rely on two complementary but separate approaches: editing via painting or clicking constraints. In this work, we provide a novel, unified approach for interactive editing of pairwise image boundaries that combines the ease of painting with the direct control of constraints. Rather than a sequential coupling, this new formulation allows full use of both interactions simultaneously, giving users unprecedented flexibility for fast boundary editing. To enable this new approach, we provide technical advancements. In particular, we detail a reformulation of image boundaries as a problem of finding cycles, expanding and correcting limitations of the previous work. Our new formulation provides boundary solutions for painted regions with performance on par with state-of-the-art specialized, paint-only techniques. In addition, we provide instantaneous exploration of the boundary solution space with user constraints. Finally, we provide examples of common graphics applications impacted by our new approach.

  11. Evaluating Search Engine Relevance with Click-Based Metrics (United States)

    Radlinski, Filip; Kurup, Madhu; Joachims, Thorsten

    Automatically judging the quality of retrieval functions based on observable user behavior holds promise for making retrieval evaluation faster, cheaper, and more user centered. However, the relationship between observable user behavior and retrieval quality is not yet fully understood. In this chapter, we expand upon, Radlinski et al. (How does clickthrough data reflect retrieval quality, In Proceedings of the ACM Conference on Information and Knowledge Management (CIKM), 43-52, 2008), presenting a sequence of studies investigating this relationship for an operational search engine on the e-print archive. We find that none of the eight absolute usage metrics we explore (including the number of clicks observed, the frequency with which users reformulate their queries, and how often result sets are abandoned) reliably reflect retrieval quality for the sample sizes we consider. However, we find that paired experiment designs adapted from sensory analysis produce accurate and reliable statements about the relative quality of two retrieval functions. In particular, we investigate two paired comparison tests that analyze clickthrough data from an interleaved presentation of ranking pairs, and find that both give accurate and consistent results. We conclude that both paired comparison tests give substantially more accurate and sensitive evaluation results than the absolute usage metrics in our domain.

  12. Tandem "click" reactions at acetylene-terminated Si(100) monolayers. (United States)

    Ciampi, Simone; James, Michael; Michaels, Pauline; Gooding, J Justin


    We demonstrate a simple method for coupling alkynes to alkynes. The method involves tandem azide-alkyne cycloaddition reactions ("click" chemistry) for the immobilization of 1-alkyne species onto an alkyne modified surface in a one-pot procedure. In the case presented, these reactions take place on a nonoxidized Si(100) surface although the approach is general for linking alkynes to alkynes. The applicability of the method in the preparation of electrically well-behaved functionalized surfaces is demonstrated by coupling an alkyne-tagged ferrocene species onto alkyne-terminated Si(100) surfaces. The utility of the approach in biotechnology is shown by constructing a DNA sensing interface by derivatization of the acetylenyl surface with commercially available alkyne-tagged oligonucleotides. Cyclic voltametry, electrochemical impedance spectroscopy, X-ray photoelectron spectroscopy, and X-ray reflectometry are used to characterize the coupling reactions and performance of the final modified surfaces. These data show that this synthetic protocol gives chemically well-defined, electronically well-behaved, and robust (bio)functionalized monolayers on silicon semiconducting surfaces.

  13. Predicting user click behaviour in search engine advertisements (United States)

    Daryaie Zanjani, Mohammad; Khadivi, Shahram


    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.

  14. Low fouling polysulfone ultrafiltration membrane via click chemistry

    KAUST Repository

    Xie, Yihui


    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%).

  15. Effect of dietary phosphorus level and source on productive performance and egg quality of two commercial strains of laying hens. (United States)

    Said, N W; Sullivan, T W; Sunde, M L; Bird, H R


    An experiment was conducted to study the influence of dietary total phosphorus (TP) level and source on the performance of two strains of commercial layers for two consecutive production years (26 to 68 and 76 to 116 weeks of age, respectively). Diet 1 contained .4% TP; Diets 2, 3 and 4 contained .5, .6, and .7% TP with supplemental P from dicalcium phosphate (DCP); Diets 5 and 6 contained .5 and .6% TP, respectively, with supplemental P from a sample of raw rock phosphate (RRP-1); Diets 7 and 8 contained .5 and .6% TP, respectively, with supplemental P from a second sample of raw rock phosphate (RRP-2). Calcium level was 2.75% in all diets, and crushed oyster shell provided ad libitum to all birds increased the total calcium to about 3.00%. Diet 1 was inferior to the average of all supplemented diets relative to feed consumption rate (P less than .005) and egg weight (P less than .005) during the first year. Diet 1 was also inferior relative to egg production rate (P less than .01), feed consumption rate (P less than .005), and egg weight (P less than .005) during the second year, whereas it was superior in shell quality (P less than .05) during the first year. Increasing TP from DCP resulted in a significant linear increase in feed consumption (P less than .05), feed conversion ratio, and Haugh units (P less than .005). Increasing TP from DCP also resulted in a significant linear decrease in shell quality (P less than .05) and significant linear and quadratic decreases in egg weight (P less than .005) during the first year. During the second year, increasing TP from DCP resulted in a significant linear decrease in egg production rate (P less than .005) and feed efficiency but significant linear (P less than .01) and quadratic (P less than .05) increases in feed consumption, and significant linear and quadratic increases (P less than .005) in Haugh units. Hens receiving RRP diets responded differently during the first and second years. The DCP supported greater

  16. Crosslinking of Kapok Cellulose Fiber via Azide Alkyne Click Chemistry as a New Material for Filtering System: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Nur Syazwani Abd Rahman


    Full Text Available A new class of green material has been elaborated by grafting the modified kapok fiber, by the means of azidated kapok fiber followed by “click-chemistry” reaction with the terminal alkyne crosslinker. The modified and synthesized product was characterized using Fourier transform infrared spectroscopy (FT-IR, and Scanning electron microscopy (SEM. The study also was undertaken to investigate the effect on the absorption of methylene blue from aqueous solution onto the click fiber prepared. The findings showed that the click kapok absorbed more compared to the untreated kapok. Based on the result, the reaction of click chemistry influenced the properties of the filter made from kapok fiber.

  17. A New Radio Frequency Plasma Oxygen Primary Ion Source on Nano Secondary Ion Mass Spectrometry for Improved Lateral Resolution and Detection of Electropositive Elements at Single Cell Level. (United States)

    Malherbe, Julien; Penen, Florent; Isaure, Marie-Pierre; Frank, Julia; Hause, Gerd; Dobritzsch, Dirk; Gontier, Etienne; Horréard, François; Hillion, François; Schaumlöffel, Dirk


    An important application field of secondary ion mass spectrometry at the nanometer scale (NanoSIMS) is the detection of chemical elements and, in particular, metals at the subcellular level in biological samples. The detection of many trace metals requires an oxygen primary ion source to allow the generation of positive secondary ions with high yield in the NanoSIMS. The duoplasmatron oxygen source is commonly used in this ion microprobe but cannot achieve the same quality of images as the cesium primary ion source used to produce negative secondary ions (C(-), CN(-), S(-), P(-)) due to a larger primary ion beam size. In this paper, a new type of an oxygen ion source using a rf plasma is fitted and characterized on a NanoSIMS50L. The performances of this primary ion source in terms of current density and achievable lateral resolution have been characterized and compared to the conventional duoplasmatron and cesium sources. The new rf plasma oxygen source offered a net improvement in terms of primary beam current density compared to the commonly used duoplasmatron source, which resulted in higher ultimate lateral resolutions down to 37 nm and which provided a 5-45 times higher apparent sensitivity for electropositive elements. Other advantages include a better long-term stability and reduced maintenance. This new rf plasma oxygen primary ion source has been applied to the localization of essential macroelements and trace metals at basal levels in two biological models, cells of Chlamydomonas reinhardtii and Arabidopsis thaliana.

  18. Effects of two protein sources and energy level of diet on the performance of young Marchigiana bulls. 2. Meat quality

    Directory of Open Access Journals (Sweden)

    Federico Infascelli


    Full Text Available The aim of this trial was to study the influence of two protein sources (faba bean-FB vs soybean meal s.e.-SBM and two energy levels of diets given to young Marchigiana bulls on meat quality: water holding capacity (WHC, chemical composition, hydroxyproline and cholesterol contents, fatty acids profile of intramuscular, subcutaneous and perirenal adipose tissues. While chemical composition and WHC was determined only on muscle Longissimus thoracis (LT, hydroxyproline and cholesterol contents were evaluated also on muscles Semitendinosus (ST and Ileopsoas plus Psoas minor (IP. Eighteen young bulls were divided into three groups. Until the slaughter weight (620 kg was achieved, two groups, FB and SBM, were fed diets with similar protein and energy contents but differing in protein sources, and the third group was fed high energy (HE diets. Protein sources did not affect meat nutritional characteristics; but meat of group SBM had high hydroxyproline content: 62.6 vs 60.0 mg 100g-1, respectively, for SBM and FB groups (P<0.05, while compression losses were higher for FB group (7.6 vs 5.7%, respectively, for FB and SBM groups; P<0.01. As respects the comparison among content of hydroxyproline in the different muscles: IP, corresponding to the tenderloin, showed significantly lower concentrations than the other muscles (55.2 vs 60.7 and 63.5 mg 100g-1 for IP, LT and ST, respectively; P<0.01. Feeding regimes did not affect muscular cholesterol content (average values of 53.6, 55.5 and 52.1 mg 100g-1 of fresh muscle for FB, SBM and HE, respectively which was similar to the levels found in meat from specialised Italian beef breeds and lower than those from other breeds. As respects the differences in cholesterol contents among the muscles, IP showed lower contents than other muscles (50.9 vs 54.1, 56.0 mg 100g-1, respectively for IP, ST, LT; P<0.05. The higher energy diets induced higher concentration of saturated fatty acids, in particular of palmitic

  19. Perceived sources and levels of stress, general self-efficacy and coping strategies in clinical dental students. (United States)

    Ersan, Nilüfer; Fişekçioğlu, Erdoğan; Dölekoğlu, Semanur; Oktay, İnci; İlgüy, Dilhan


    The aims of this study were to identify sources of stress among clinical students and to evaluate the students' perceived levels of stress, general self-efficacy and effective coping strategies in a private dental school environment. The study group consisted of 130 undergraduate clinical dental students in a Turkish private dental school, during the academic year 2014-2015. The students were surveyed using modified version of the dental environment stress (DES) survey, the perceived stress scale, the general self-efficacy scale (G-SES) and the brief coping scale. Age, sex, year of study, history of psychiatric treatment and factors that affected the choice of dentistry were also recorded. Final year and female clinical dental students, who were found to be the most stressful students, had moderate to high perceived stress scores. Total and 'Faculty and administration' related DES scores increased with the year of study. Stressors related to 'Workload' and 'Clinical training' affected females more than males. G-SES scores were higher in male students and students, who had no history of psychiatric treatment. The most and the least common coping strategies were 'Planning' and 'Substance abuse', respectively. 'Religion' was found to be one of the main coping strategies. Stress factors affecting Turkish clinical dental students studying at private dental school differed from the previously reported stress factors affecting students studying at a governmental dental school. Advanced year and female students experienced more stress than the other students.

  20. ;Click; analytics for ;click; chemistry - A simple method for calibration-free evaluation of online NMR spectra (United States)

    Michalik-Onichimowska, Aleksandra; Kern, Simon; Riedel, Jens; Panne, Ulrich; King, Rudibert; Maiwald, Michael


    Driven mostly by the search for chemical syntheses under biocompatible conditions, so called ;click; chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of 1H spectra with a time interval of 20 s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibration-free approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9 h-1 at 25 °C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance.

  1. On the use of click-evoked electric brainstem responses in audiological diagnosis. IV. Interaural latency differences (wave V) in cochlear hearing loss. (United States)

    Rosenhamer, H J; Lindström, B; Lundborg, T


    Interaural latency differences (ILDs) of wave V of the brainstem electric response (BSER) were studied (1) in 20 normal-hearing subjects at 90, 80, 60 and 40 dB HL click level, (2) in 22 patients with symmetrical cochlear hearing loss at 90 dB HL, corresponding to 45-80 dB SL, and (3) in 45 patients with asymetrical cochlear hearing loss with interaural recruitment, at 90 dB HL on one hand and at a click sensation level corresponding to 90 dB HL in the poorer ear (range 10-75 dB SL) on the other hand. In the normal hearing group the ILDs did not exceed 0.2 ms except in one case at 40 dB HL (0.3 ms). In the symmetrical cochlear loss group the ILD did not exceed 0.2 ms in any patient. In the asymmetrical cochlear loss group the ILD at 90 dB HL exceeded 0.2 ms in 12 cases, but only in four cases after correction for pure tone hearing loss at 4 kHz by 0.1 for each 10 dB above 50 dB HL; at equal sensation levels the ILDs were all zero or negative meaning that the wave V latency was shorter on stimulation of the poorer ear. Assuming ILD to be a valid discriminator between cochlear and retrocochlear lesions, the corrected ILD at equal click hearing levels (90 dB HL), with the critical value set at 0.2 ms, thus gave a 9% false-positive rate whereas the ILS at equal sensation levels, with the critical value set at zero, gave no false-positives. It still remains to be shown that the latter criterion will not increase the number of false-negative results in retrocochlear lesions.

  2. Comparative Analysis of Nanoparticle-Antibody Conjugations: Carbodiimide Versus Click Chemistry

    Directory of Open Access Journals (Sweden)

    Daniel L.J. Thorek


    Full Text Available The ability to modify the physical, chemical, and biologic properties of nanoparticles has led to their use as multifunctional platforms for drug delivery and diagnostic imaging applications. Typically, these applications involve functionalizing the nanoparticles with targeting agents. Antibodies remain an attractive choice as targeting agents because of their large epitope space and high affinity; however, implementation of antibody-nanoparticle conjugates is plagued by low coupling efficiencies and the high cost of reagents. Click chemistry may provide a solution to this problem, with reported coupling efficiencies nearing 100%. Although click chemistries have been used to functionalize nanoparticles with small molecules, they have not previously been used to functionalize nanoparticles with antibodies. Concerns associated with extending this procedure to antibodies are that reaction catalysts or the ligands required for cross-linking may result in loss of functionality. We evaluated the efficiency of conjugations between antibodies and superparamagnetic iron oxide nanoparticles using click chemistry as well as the functionality of the product. The results were compared with conjugates formed through carbodiimide cross-linking. The click reaction allowed for a higher extent and efficiency of labeling compared with carbodiimide, thus requiring less antibody. Further, conjugates prepared via the click reaction exhibited improved binding to target receptors.

  3. Click chemistry armed enzyme-linked immunosorbent assay to measure palmitoylation by hedgehog acyltransferase. (United States)

    Lanyon-Hogg, Thomas; Masumoto, Naoko; Bodakh, George; Konitsiotis, Antonio D; Thinon, Emmanuelle; Rodgers, Ursula R; Owens, Raymond J; Magee, Anthony I; Tate, Edward W


    Hedgehog signaling is critical for correct embryogenesis and tissue development. However, on maturation, signaling is also found to be aberrantly activated in many cancers. Palmitoylation of the secreted signaling protein sonic hedgehog (Shh) by the enzyme hedgehog acyltransferase (Hhat) is required for functional signaling. To quantify this important posttranslational modification, many in vitro Shh palmitoylation assays employ radiolabeled fatty acids, which have limitations in terms of cost and safety. Here we present a click chemistry armed enzyme-linked immunosorbent assay (click-ELISA) for assessment of Hhat activity through acylation of biotinylated Shh peptide with an alkyne-tagged palmitoyl-CoA (coenzyme A) analogue. Click chemistry functionalization of the alkyne tag with azido-FLAG peptide allows analysis through an ELISA protocol and colorimetric readout. This assay format identified the detergent n-dodecyl β-d-maltopyranoside as an improved solubilizing agent for Hhat activity. Quantification of the potency of RU-SKI small molecule Hhat inhibitors by click-ELISA indicated IC50 values in the low- or sub-micromolar range. A stopped assay format was also employed that allows measurement of Hhat kinetic parameters where saturating substrate concentrations exceed the binding capacity of the streptavidin-coated plate. Therefore, click-ELISA represents a nonradioactive method for assessing protein palmitoylation in vitro that is readily expandable to other classes of protein lipidation.

  4. Simultaneous electropolymerization and electro-click functionalization for highly versatile surface platforms. (United States)

    Rydzek, Gaulthier; Terentyeva, Tatyana G; Pakdel, Amir; Golberg, Dmitri; Hill, Jonathan P; Ariga, Katsuhiko


    Simple preparation methods of chemically versatile and highly functionalizable surfaces remain rare and present a challenging research objective. Here, we demonstrate a simultaneous electropolymerization and electro-click functionalization process (SEEC) for one-pot self-construction of aniline- and naphthalene-based functional polymer films where both polymerization and click functionalization are triggered by applying electrochemical stimuli. Cyclic voltammetry (CV) can be applied for the simultaneous oxidation of 4-azidoaniline and the reduction of Cu(II) ions, resulting in polymerization of the former, and the Cu(I)-catalyzed alkyne/azide cycloaddition ("click" chemistry). Properties of the films obtained can be tuned by varying their morphology, their chemically "clicked" content, or by postconstruction functionalization. To demonstrate this, the CV scan rates, component monomers, and "clicked" molecules were varied. Covalent postconstruction immobilization of horseradish peroxidase was also performed. Consequently, pseudocapacitance and enzyme activity were affected. SEEC provides surface scientists an easy access to a wide range of functionalization possibilities in several fields including sensors, fuel cells, photovoltaics, and biomaterials.

  5. Click hydrogels, microgels and nanogels: emerging platforms for drug delivery and tissue engineering. (United States)

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


    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.

  6. Contributions to cities' ambient particulate matter (PM): A systematic review of local source contributions at global level (United States)

    Karagulian, Federico; Belis, Claudio A.; Dora, Carlos Francisco C.; Prüss-Ustün, Annette M.; Bonjour, Sophie; Adair-Rohani, Heather; Amann, Markus


    For reducing health impacts from air pollution, it is important to know the sources contributing to human exposure. This study systematically reviewed and analysed available source apportionment studies on particulate matter (of diameter of 10 and 2.5 microns, PM10 and PM2.5) performed in cities to estimate typical shares of the sources of pollution by country and by region. A database with city source apportionment records, estimated with the use of receptor models, was also developed and available at the website of the World Health Organization. Systematic Scopus and Google searches were performed to retrieve city studies of source apportionment for particulate matter. Six source categories were defined. Country and regional averages of source apportionment were estimated based on city population weighting. A total of 419 source apportionment records from studies conducted in cities of 51 countries were used to calculate regional averages of sources of ambient particulate matter. Based on the available information, globally 25% of urban ambient air pollution from PM2.5 is contributed by traffic, 15% by industrial activities, 20% by domestic fuel burning, 22% from unspecified sources of human origin, and 18% from natural dust and salt. The available source apportionment records exhibit, however, important heterogeneities in assessed source categories and incompleteness in certain countries/regions. Traffic is one important contributor to ambient PM in cities. To reduce air pollution in cities and the substantial disease burden it causes, solutions to sustainably reduce ambient PM from traffic, industrial activities and biomass burning should urgently be sought. However, further efforts are required to improve data availability and evaluation, and possibly to combine with other types of information in view of increasing usefulness for policy making.

  7. Liposome functionalization with copper-free "click chemistry". (United States)

    Oude Blenke, Erik; Klaasse, Gruson; Merten, Hannes; Plückthun, Andreas; Mastrobattista, Enrico; Martin, Nathaniel I


    The modification of liposomal surfaces is of interest for many different applications and a variety of chemistries are available that makes this possible. A major disadvantage of commonly used coupling chemistries (e.g. maleimide-thiol coupling) is the limited control over the site of conjugation in cases where multiple reactive functionalities are present, leading to heterogeneous products and in some cases dysfunctional conjugates. Bioorthogonal coupling approaches such as the well-established copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" reaction are attractive alternatives as the reaction kinetics are favorable and azide-containing reagents are widely available. In the work described here, we prepared lipids containing a reactive cyclooctyne group and, after incorporation into liposomes, demonstrated successful conjugation of both a small molecule dye (5'-TAMRA-azide) as well as a larger azide-containing model protein based upon a designed ankyrin repeat protein (azido-DARPin). By applying the strain-promoted azido-alkyne cycloaddition (SPAAC) the use of Cu(I) as a catalyst is avoided, an important advantage considering the known deleterious effects associated with copper in cell and protein studies. We demonstrate complete control over the number of ligands coupled per liposome when using a small molecule azide with conjugation occurring at a reasonable reaction rate. By comparison, the conjugation of a larger azide-modified protein occurs more slowly, however the number of protein ligands coupled was found to be sufficient for liposome targeting to cells. Importantly, these results provide a strong proof of concept for the site-specific conjugation of protein ligands to liposomal surfaces via SPAAC. Unlike conventional approaches, this strategy provides for the homogeneous coupling of proteins bearing a single site-specific azide modification and eliminates the chance of forming dysfunctional ligands on the liposome. Furthermore, the absence of

  8. Labeling proteins on live mammalian cells using click chemistry. (United States)

    Nikić, Ivana; Kang, Jun Hee; Girona, Gemma Estrada; Aramburu, Iker Valle; Lemke, Edward A


    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.

  9. Evaluation of nitrogen and organic matter balance in the feedlot as affected by level and source of dietary fiber. (United States)

    Bierman, S; Erickson, G E; Klopfenstein, T J; Stock, R A; Shain, D H


    A trial was conducted to determine the effect of level and source of dietary fiber on N and OM excretion by cattle on finishing diets. One hundred twenty steers were stratified by weight and allotted to one of the following treatments: 7.5% roughage (7.5% R), wet corn gluten feed (WCGF; 41.5% of dietary DM), and all-concentrate (All Con) diet. Cattle were fed for 87 d during the summer with 23.7 m2 of pen area per animal. Steers fed the WCGF diet had heavier final weights, greater DMI, and higher ADG (P < .01) than the 7.5% R and All Con treatments. Steers fed All Con had lower (P < .01) DMI than the other two treatments. Nitrogen and OM mass balances in the feedlot were quantified. Main components were nutrient input, retention, and excretion. Nitrogen and OM intake of steers fed WCGF were greater (P < .05) than those of steers fed the other treatments. The WCGF treatment had a greater percentage of fecal N output (P < .05). The All Con treatment had a greater (P < .01) percentage of urinary N than WCGF and 7.5% R diets. Steers fed the WCGF treatment excreted more (P < .01) OM compared with the other treatments, which led to more N and OM being removed in manure at cleaning. The All Con treatment had more (P < .01) N and OM in runoff than the other treatments. Nutrition can change site of fermentation, which affects the composition of excreted material; however, total amount of N excreted may be more important than route of excretion in decreasing N losses to the environment and maximizing recovery in manure.

  10. The growing impact of bioorthogonal click chemistry on the development of radiopharmaceuticals. (United States)

    Zeng, Dexing; Zeglis, Brian M; Lewis, Jason S; Anderson, Carolyn J


    Click chemistry has become a ubiquitous chemical tool with applications in nearly all areas of modern chemistry, including drug discovery, bioconjugation, and nanoscience. Radiochemistry is no exception, as the canonical Cu(I)-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, inverse electron demand Diels-Alder reaction, and other types of bioorthogonal click ligations have had a significant impact on the synthesis and development of radiopharmaceuticals. This review will focus on recent applications of click chemistry ligations in the preparation of imaging agents for SPECT and PET, including small molecules, peptides, and proteins labeled with radionuclides such as (18)F, (64)Cu, (111)In, and (99m)Tc.

  11. Silane meets click chemistry: towards the functionalization of wet bacterial cellulose sheets. (United States)

    Hettegger, Hubert; Sumerskii, Ivan; Sortino, Salvatore; Potthast, Antje; Rosenau, Thomas


    The modification of cellulosic materials is of great interest in materials research. Wet bacterial cellulose sheets were modified by an alkoxysilane under mild conditions to make them accessible to click chemistry derivatization. For this purpose (3-azidopropyl)triethoxysilane was grafted covalently onto the cellulosic surface. The silanized bacterial cellulose sheets were characterized comprehensively by attenuated total reflectance FTIR spectroscopy, solid-state NMR spectroscopy, thermogravimetric analysis, SEM with energy-dispersive X-ray spectroscopy, and elemental analysis. To demonstrate subsequent click chemistry functionalization, a new fluorophore based on fluorescein was synthesized and clicked to the silane-modified bacterial cellulose. The new method renders bacterial cellulose and other never-dried cellulosic materials susceptible to direct and facile functionalization in an aqueous medium without the need to work in water-free organic phases or to employ extensive protecting group chemistry and functional group interconversion.

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

    Directory of Open Access Journals (Sweden)

    Razvan PETRUSEL


    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.

  13. Click chemistry” preparation of WCX packings for protein separation

    Institute of Scientific and Technical Information of China (English)

    Kai Lou Zhao; Chao Song; Fei Wang; Quan Bai


    Click chemistry was applied to immobilize three kinds of alkyne-carboxylic acids onto azide-modified silica gel to prepare three novel stationary phases for weak cation exchange chromatography (WCX).The developed protocol combines the benefits of operational simplicity,exceptionally mild conditions and high surface loadings.Six kinds of standard proteins were separated completely on the novel packings.Compared with commercial WCX columns,the three kinds of novel WCX packings prepared by click chemistry approach have better resolution and selectivity.Lysozyme was purified successfully from egg white with the novel WCX column by one step.The purity was more than 97% and a high specific activity was achieved to be 81,435 U/mg.The results illustrate the potential of click chemistry for preparation of stationary phase for IEC.

  14. Evaluating Intellectual Property and Data Rights in Competition Source Selections - Leveraging the Assertions Process to a New Level to Foster Open Systems Architecture (United States)


    ååì~ä=^Åèìáëáíáçå= oÉëÉ~êÅÜ=póãéçëáìã= qÜìêëÇ~ó=pÉëëáçåë= sçäìãÉ=ff= = Evaluating Intellectual Property and Data Rights in Competition Source...SUBTITLE Evaluating Intellectual Property and Data Rights in Competition Source Selections - Leveraging the ’Assertions Process’ to a New Level to...effectively evaluate intellectual property in source selections to ensure the Government gets the intellectual property rights it needs to procure

  15. Selective Bifunctional Modification of a Non-catenated Metal-Organic Framework Material via 'Click' Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Gadzikwa, Tendai; Farha, Omar K.; Malliakas, Christos D.; Kanatzidis, Mercouri G.; Hupp, Joseph T.; Nguyen, SonBinh T.; NWU


    A noncatenated, Zn-based metal-organic framework (MOF) material bearing silyl-protected acetylenes was constructed and postsynthetically modified using 'click' chemistry. Using a solvent-based, selective deprotection strategy, two different organic azides were 'clicked' onto the MOF crystals, resulting in a porous material whose internal and external surfaces are differently functionalized.

  16. Research data supporting "Differentiation of online text-based advertising and the effect on users’ click behavior"


    Jacques, Jason T.; Kristensson, Per Ola


    Click data for "Differentiation of Online Text-based Advertising and the Effect on Users’ Click Behavior" as published in "Computers in Human Behavior" ( This work was supported by the Engineering and Physical Research Council [DTA]. ESPRC

  17. The function of male sperm whale slow clicks in a high latitude habitat: communication, echolocation, or prey debilitation? (United States)

    Oliveira, Cláudia; Wahlberg, Magnus; Johnson, Mark; Miller, Patrick J O; Madsen, Peter T


    Sperm whales produce different click types for echolocation and communication. Usual clicks and buzzes appear to be used primarily in foraging while codas are thought to function in social communication. The function of slow clicks is less clear, but they appear to be produced by males at higher latitudes, where they primarily forage solitarily, and on the breeding grounds, where they roam between groups of females. Here the behavioral context in which these vocalizations are produced and the function they may serve was investigated. Ninety-nine hours of acoustic and diving data were analyzed from sound recording tags on six male sperm whales in Northern Norway. The 755 slow clicks detected were produced by tagged animals at the surface (52%), ascending from a dive (37%), and during the bottom phase (11%), but never during the descent. Slow clicks were not associated with the production of buzzes, other echolocation clicks, or fast maneuvering that would indicate foraging. Some slow clicks were emitted in seemingly repetitive temporal patterns supporting the hypothesis that the function for slow clicks on the feeding grounds is long range communication between males, possibly relaying information about individual identity or behavioral states.

  18. 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;


    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......-alkyne cycloaddition (CuAAC) was demonstrated by efficient conjugation (up to 92%) of phosphocholine, a near infrared dye, and poly(ethylene glycol) (PEG) with different substitution degrees, either alone or in combination. This study introduces a novel and versatile method to synthesize well-defined click...

  19. 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


    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.

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


    Youlong Zhuang; Albert L. Lederer


    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...

  1. Investigating peptide sequence variations for 'double-click' stapled p53 peptides. (United States)

    Lau, Yu Heng; de Andrade, Peterson; Sköld, Niklas; McKenzie, Grahame J; Venkitaraman, Ashok R; Verma, Chandra; Lane, David P; Spring, David R


    Stapling peptides for inhibiting the p53/MDM2 interaction is a promising strategy for developing anti-cancer therapeutic leads. We evaluate double-click stapled peptides formed from p53-based diazidopeptides with different staple positions and azido amino acid side-chain lengths, determining the impact of these variations on MDM2 binding and cellular activity. We also demonstrate a K24R mutation, necessary for cellular activity in hydrocarbon-stapled p53 peptides, is not required for analogous 'double-click' peptides.

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

    Directory of Open Access Journals (Sweden)

    Matteo Colombo


    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.

  3. Amplitude and phase equalization of stimuli for click evoked auditory brainstem responses. (United States)

    Beutelmann, Rainer; Laumen, Geneviève; Tollin, Daniel; Klump, Georg M


    Although auditory brainstem responses (ABRs), the sound-evoked brain activity in response to transient sounds, are routinely measured in humans and animals there are often differences in ABR waveform morphology across studies. One possible reason may be the method of stimulus calibration. To explore this hypothesis, click-evoked ABRs were measured from seven ears in four Mongolian gerbils (Meriones unguiculatus) using three common spectrum calibration strategies: Minimum phase filter, linear phase filter, and no filter. The results show significantly higher ABR amplitude and signal-to-noise ratio, and better waveform resolution with the minimum phase filtered click than with the other strategies.

  4. The use of click chemistry in the emerging field of catalomics. (United States)

    Kalesh, Karunakaran A; Shi, Haibin; Ge, Jingyan; Yao, Shao Q


    Of the thousands of known chemical reactions, a handful of reactions, called "click" reactions, stand out with features such as good chemoselectivity, good solvent compatibilities, modularity, minimum synthetic demands, bioorthogonality and high yields. Among them, the Cu(i)-catalyzed 1,3-dipolar cycloaddition reaction between azides and terminal alkynes has emerged as a powerful tool in chemical biology and proteomics. This perspective surveys the significant contributions of click chemistry in catalomics (a sub-area in chemical proteomics), with special emphasis on activity-based protein profiling (ABPP), posttranslational modifications (PTMs) and enzyme inhibitor developments.

  5. Preparation of a novel carboxyl stationary phase by "thiol-ene" click chemistry for hydrophilic interaction chromatography. (United States)

    Peng, Xi-Tian; Liu, Tao; Ji, Shu-Xian; Feng, Yu-Qi


    A novel carboxyl-bonded silica stationary phase was prepared by "thiol-ene" click chemistry. The resultant Thiol-Click-COOH phase was evaluated under hydrophilic interaction liquid chromatography (HILIC) mobile phase conditions. A comparison of the chromatographic performance of Thiol-Click-COOH and pure silica columns was performed according to the retention behaviors of analytes and the charged state of the stationary phases. The results indicated that the newly developed Thiol-Click-COOH column has a higher surface charge and stronger hydrophilicity than the pure silica column. Furthermore, the chromatographic behaviors of five nucleosides on the Thiol-Click-COOH phase were investigated in detail. Finally, a good separation of 13 nucleosides and bases, and four water-soluble vitamins was achieved.

  6. 基于SCIE的有关"Click chemistry"研究论文分析%Study of the Papers of Click Chemistry based on SCIE

    Institute of Scientific and Technical Information of China (English)



    依据Web of Science平台下的SCIE数据库中2001-2014年间有关"Click chemistry"的论文数据和文献计量方法,从发表年份、国家、机构、期刊和研究方向等进行聚类分析,研究"Click chemistry"自首次提出后的研究发展情况.结果表明,美国发表相关论文的数量和质量均位居世界第一.中国的发文量排名第二,但是论文质量和世界先进水平仍有一定差距.

  7. A 7-Level Single DC Source Cascaded H-Bridge Multilevel Inverter with a Modified DTC Scheme for Induction Motor-Based Electric Vehicle Propulsion

    Directory of Open Access Journals (Sweden)

    Farid Khoucha


    Full Text Available This paper presents a new hybrid cascaded H-bridge multilevel inverter motor drive DTC scheme for electric vehicles where each phase of the inverter can be implemented using a single DC source. Traditionally, each phase of the inverter requires DC source for output voltage levels. In this paper, a scheme is proposed that allows the use of a single DC source as the first DC source which would be available from batteries or fuel cells, with the remaining ( DC sources being capacitors. This scheme can simultaneously maintain the capacitors of DC voltage level and produce a nearly sinusoidal output voltage due to its high number of output levels. In this context, high performances and efficient torque and flux control are obtained, enabling a DTC solution for hybrid multilevel inverter powered induction motor drives intended for electric vehicle propulsion. Simulations and experiments show that the proposed multilevel inverter and control scheme are effective and very attractive for embedded systems such as automotive applications.

  8. Identifying sediment sources and delivery mechanisms using background level polycyclic aromatic hydrocarbons in the Waiapu River watershed, New Zealand (United States)

    Thompson, C. E.; Nichols, E. G.; Johnson, G.; Blair, N. E.; Leithold, E. L.; Palmer, A. S.; Baisden, W. T.


    The significant contribution of small mountainous river systems to the global fluvial sediment supply motivates investigation into the processes that influence the composition of the organic carbon that they carry. Organic matter preserved in continental margin sediments originates from terrestrial sources, such as kerogen and fresh and aged soil carbon, as well as marine sources. The identification of specific terrestrial fractions buried can facilitate interpretation of the organic geochemical record and enable reconstruction of watershed history. Carbon isotopic analyses have been used to apportion terrestrial carbon fractions preserved in marine environments; however, they have been generally limited to resolving modern C and kerogen. In this study, the use of polycyclic aromatic hydrocarbons (PAHs) to examine sediment production in the Waiapu watershed, New Zealand has been investigated. A suite of 42 alkylated and non-alkylated PAH concentrations establish chemical fingerprints for likely terrestrial sources of organic matter feeding the river and margin. Principal component analysis reveals chemical similarity between source and sink based on the degree of weathering and the relative inputs of petrogenic and pyrogenic PAHs. The primary sources of terrestrial organic matter buried over recent history on the continental shelf are Cretaceous bedrock, raw riverbank soils, and pastoral topsoils. Polytopic vector analysis of marine sediment establishes PAH end-member profiles, allowing sedimentary carbon on the shelf to be apportioned to contributing sources. These end-member model profiles confirm the PCA results, corresponding to PAH fingerprints of potential terrestrial sources including (1) bedrock composed of ancient kerogen, (2) soils from riverbank profiles that are composed of mixtures of ancient, aged, and modern carbon, and (3) topsoils typically composed of modern carbon from plant or fire-derived organic matter. Resolution of these sources suggests

  9. The Research of Static Var Compensator's Time Characteristics and System-level Model of Controlled Current Source (United States)

    Zhang, Chao; Jiang, Qi-rong; Sun, Shou-xin

    In the status of lacking research on response time of static var compensator (SVC), this paper established the controlled current source model which can achieve the same effect in response time and reactive compensation with the physical model of SVC by analyzing of characteristics in reactive power compensation and the response of the static var compensator (SVC) physical model. Through the time module in control signal of controlled current source, it can accurately calculate the response time of SVC. It tested the consistency of two models through the simulation of a rolling mill start experiment in PSCAD.

  10. Functional monolayers on oxide-free silicon surfaces via thiol–ene click chemistry

    NARCIS (Netherlands)

    Caipa Campos, Mabel A.; Paulusse, Jos M.J.; Zuilhof, Han


    Thiol–ene click chemistry was used for the attachment of a variety of functional molecules onto oxide-free Si(111) surfaces using very mild conditions; the efficient nature of this coupling strategy allowed for successful light-induced micropatterning and thus provides a novel route towards biofunct

  11. Injectable dextran hydrogels fabricated by metal-free click chemistry for cartilage tissue engineering. (United States)

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


    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-N3). 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-N3 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.

  12. A Click Chemistry Approach towards Flavin-Cyclodextrin Conjugates-Bioinspired Sulfoxidation Catalysts. (United States)

    Tomanová, Petra; Šturala, Jiří; Buděšínský, Miloš; Cibulka, Radek


    A click chemistry approach based on the reaction between alkynylflavins and mono(6-azido-6-deoxy)-β-cyclodextrin has proven to be a useful tool for the synthesis of flavin-cyclodextrin conjugates studied as monooxygenase mimics in enantioselective sulfoxidations.

  13. Preparation of weak cation exchange packings for chromatographic separation of proteins using "click chemistry''. (United States)

    Zhao, Kailou; Bai, Quan; Song, Chao; Wang, Fei; Yang, Fan


    "Click chemistry" is defined as a class of robust and selective chemical reactions affording high yields and is tolerant to a variety of solvents (including water), functional groups, and air. In this study, click chemistry was used as an effective strategy for coupling three alkyne-carboxylic acids onto the azide-silica to obtain three novel stationary phases of weak cation exchange chromatography, which were characterized with FTIR and elemental analysis. Six kinds of standard proteins, such as myoglobin, RNase A, RNase B, cytochrome C, α-chymotrypsin A, and lysozyme, were separated completely with the three novel weak cation exchange chromatography stationary phases. Compared with commercial weak cation exchange chromatography columns, the three kinds of novel weak cation exchange chromatography packings prepared by click chemistry approach have better resolution and selectivity. The mass recovery of more than 97% was obtained for all the tested proteins, and the bioactivity recovery of lysozyme on the prepared column was determined to be 96%. In addition, lysozyme was purified successfully from egg white with the novel weak cation exchange chromatography column by one step. The purity was more than 97% and a high specific activity was achieved to be 81 435 U/mg. The results illustrate the potential of click chemistry for preparing stationary phase for ion-exchange chromatography.

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

    Directory of Open Access Journals (Sweden)

    Marina Bantzi


    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.

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


    Petra Tomanová; Jiří Šturala; Miloš Buděšínský; Radek Cibulka


    A click chemistry approach based on the reaction between alkynylflavins and mono(6-azido-6-deoxy)-β-cyclodextrin has proven to be a useful tool for the synthesis of flavin-cyclodextrin conjugates studied as monooxygenase mimics in enantioselective sulfoxidations.

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

    Directory of Open Access Journals (Sweden)

    Petra Tomanová


    Full Text Available A click chemistry approach based on the reaction between alkynylflavins and mono(6-azido-6-deoxy-β-cyclodextrin has proven to be a useful tool for the synthesis of flavin-cyclodextrin conjugates studied as monooxygenase mimics in enantioselective sulfoxidations.

  17. Location of the auditory cortex in the Mongolian gerbil as determined by click stimulation. (United States)

    Gillette, R G


    An investigation was made of the auditory projection area in the cerebral cortex of the Mongolian gerbil (Meriones unguiculatus) using clicks at a standard intensity to map the cerebral hemisphere by the evoked potential method. The major results can be summarized as follows: (1) As is typical for other mammals, click-evoked responses characterizing the gerbil auditory area were initially surface-positive potentials (amplitudes ranging between 0.1 and 1.7 mV) with peak latencies ranging between 13 and 32 msec. (2) Only one click-responsive field was found in the temporal area. However, the data suggest that this area may actually represent two separate projections to the cortex, since a small subarea characterized by longer response latencies was located posteriorally and laterally within the click field in the majority of animals investigated. (3) The size (5 mm long by 4 mm wide) and location (temporal neocortex below the middle cerebral artery) of the gerbil auditory cortex are consistent with mapping results obtained in other rodent species. (4) The validity of the surface maps was confirmed in four cases by demonstrating that the evoked response reversed polarity between the cortical surface and underlying white matter. The reversal was demonstrated by recording with a penetrating microelectrode at representative points "bordering" the auditory projection area.

  18. Separation of Sperm Whale Click-Trains for Multipath Rejection and Localization (United States)


    features were selected and separated into 3 groups: [kerr, perr , aerr, K.3, D-K3], [cerr, psdot, derr, Kl, K2, K4, TSTD, TM4, D-Kl, D-K4, D-TM3], [dT... perr Log power ratio aerr Log amplitude (SNR) ratio psdot Power spectrum deviation snrmin SNR off weakest click derr Incoherent correlation

  19. New 1,2,3-Triazole Iminosugars Derivatives Using Click Chemistry

    Directory of Open Access Journals (Sweden)

    Chahrazed Benhaoua


    Full Text Available The click concept refers ease, efficient, and the selective chemicals transformations. In this study, a novel regiospecific copper (I-catalyzed 1, 3-dipolar of terminal alkynes to azide provided a practicable synthetic pathway of triazole iminosugars derivatives. A series of new triazole-pyrrolidinols are reported in good yield.

  20. Brick & Click Libraries: An Academic Library Conference (15th, Maryville, Missouri, November 6, 2015) (United States)

    Baudino, Frank, Ed.; Johnson, Carolyn, Ed.


    Nineteen scholarly papers and seventeen abstracts comprise the content of the fifteenth annual Brick and Click Libraries Conference, held annually at Northwest Missouri State University in Maryville, Missouri. The proceedings, authored by academic librarians and presented at the symposium, portray the contemporary and future face of librarianship.…

  1. Brick & Click Libraries: An Academic Library Conference (14th, Maryville, Missouri, November 7, 2014) (United States)

    Baudino, Frank, Ed.; Johnson, Carolyn, Ed.


    Eighteen scholarly papers and twelve abstracts comprise the content of the fourteenth annual Brick and Click Libraries Symposium, held annually at Northwest Missouri State University in Maryville, Missouri. The proceedings, authored by academic librarians and presented at the symposium, portray the contemporary and future face of librarianship.…

  2. Brick and Click Libraries: An Academic Library Symposium (12th, Maryville, Missouri, October 26, 2012) (United States)

    Baudino, Frank, Ed.; Johnson, Carolyn, Ed.


    Twenty scholarly papers and fifteen abstracts comprise the content of the twelfth annual Brick and Click Libraries Symposium, held at Northwest Missouri State University in Maryville, Missouri. The peer-reviewed proceedings, authored by academic librarians and presented at the symposium, portray the contemporary and future face of librarianship.…

  3. Brick & Click Libraries: An Academic Library Symposium (13th, Maryville, Missouri, November 1, 2013) (United States)

    Baudino, Frank, Ed.; Johnson, Carolyn, Ed.; Park, Sarag G., Ed.


    Twenty-six scholarly papers and ten abstracts comprise the content of the thirteenth annual Brick and Click Libraries Symposium, held annually at Northwest Missouri State University in Maryville, Missouri. The proceedings, authored by academic librarians and presented at the symposium, portray the contemporary and future face of librarianship. The…

  4. Brick and Click Libraries: Proceedings of an Academic Library Symposium (Maryville, Missouri, October 22, 2004) (United States)

    Baudino, Frank, Ed.; Mardis, Lori, Ed.; Park, Sarah G., Ed.; Ury, Connie J., Ed.


    The Brick & Click Libraries Symposium is a one-day conference that focuses on providing library resources and services for students who are either on-campus learners or off-campus learners. It is sponsored by Northwest Missouri State University in order to offer academic librarians a forum for sharing practical information. The subjects and…

  5. Extraction of pulse repetition intervals from sperm whale click trains for ocean acoustic data mining. (United States)

    Zaugg, Serge; van der Schaar, Mike; Houégnigan, Ludwig; André, Michel


    The analysis of acoustic data from the ocean is a valuable tool to study free ranging cetaceans and anthropogenic noise. Due to the typically large volume of acquired data, there is a demand for automated analysis techniques. Many cetaceans produce acoustic pulses (echolocation clicks) with a pulse repetition interval (PRI) remaining nearly constant over several pulses. Analyzing these pulse trains is challenging because they are often interleaved. This article presents an algorithm that estimates a pulse's PRI with respect to neighboring pulses. It includes a deinterleaving step that operates via a spectral dissimilarity metric. The sperm whale (SW) produces trains with PRIs between 0.5 and 2 s. As a validation, the algorithm was used for the PRI-based identification of SW click trains with data from the NEMO-ONDE observatory that contained other pulsed sounds, mainly from ship propellers. Separation of files containing SW clicks with a medium and high signal to noise ratio from files containing other pulsed sounds gave an area under the receiver operating characteristic curve value of 0.96. This study demonstrates that PRI can be used for the automated identification of SW clicks and that deinterleaving via spectral dissimilarity contributes to algorithm performance.

  6. Do User (Browse and Click) Sessions Relate to Their Questions in a Domain-specific Collection?

    DEFF Research Database (Denmark)

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


    We seek to improve information retrieval in a domain-specific col-lection by clustering user sessions as recorded in a click log and then classifying later user sessions in real-time. As a preliminary step, we explore, the main as-sumption of this approach: whether user sessions in such a site re...

  7. Nonlinear response to a click in a time-domain model of the mammalian ear. (United States)

    Meaud, Julien; Lemons, Charlsie


    In this paper, a state-space implementation of a previously developed frequency-domain model of the cochlea is coupled to a lumped parameter model of the middle ear. After validation of the time-domain model by comparison of its steady-state response to results obtained with a frequency-domain formulation, the nonlinear response of the cochlea to clicks is investigated. As observed experimentally, a compressive nonlinearity progressively develops within the first few cycles of the response of the basilar membrane (BM). Furthermore, a time-frequency analysis shows that the instantaneous frequency of the BM response to a click progressively approaches the characteristic frequency. This phenomenon, called glide, is predicted at all stimulus intensities, as in experiments. In typical experiments with sensitive animals, the click response is characterized by a long ringing and the response envelope includes several lobes. In order to achieve similar results, inhomogeneities are introduced in the cochlear model. Simulations demonstrate the strong link between characteristics of the frequency response, such as dispersion and frequency-dependent nonlinearity, and characteristics of the time-domain response, such as the glide and a time-dependent nonlinearity. The progressive buildup of cochlear nonlinearity in response to a click is shown to be a consequence of the glide and of frequency-dependent nonlinearity.

  8. Fluorescent detection of copper(II) based on DNA-templated click chemistry and graphene oxide. (United States)

    Zhou, Lifen; Shen, Qinpeng; Zhao, Peng; Xiang, Bingbing; Nie, Zhou; Huang, Yan; Yao, Shouzhuo


    A novel DNA-templated click chemistry strategy for homogenous fluorescent detection of Cu(2+) has been developed based on click ligation-dependent DNA structure switch and the selective quenching ability of graphene oxide (GO) nanosheet. The clickable duplex probe consists of two DNA strands with alkyne and azide group, respectively, and Cu(+)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction can chemically ligate these two strands. Toehold sequence displacement was consequently exploited to achieve DNA structure transformation bearing fluorescent tag FAM. Cu(2+)-induced chemical ligation caused the probe transfer to hybrid structure with single stranded DNA (ssDNA) tail, while only duplex structure was obtained without Cu(2+). This structural difference can be probed by GO-based fluorescence detection due to the preferential binding of GO to ssDNA. Under the optimum conditions, this sensor can sensitively and specifically detect Cu(2+) with a low detection limit of 58 nM and a linear range of 0.1-10 μM. This new strategy is highly sensitive and selective for Cu(2+) detection because of the great specificity of click chemistry and super-quenching ability of GO. Moreover, with the aid of high efficient DNA templated synthesis, the detection process requires only about half an hour which is much quicker than previous click-chemistry-based Cu(2+) sensors.

  9. Multi-channel services for click and mortars: development of a design method

    NARCIS (Netherlands)

    Simons, L.P.A.


    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 confirms

  10. Two consecutive click reactions as a general route to functional cyclic polyesters. (United States)

    Yuan, You-Yong; Du, Jin-Zhi; Wang, Jun


    A simple and universal route to functional cyclic polyesters has been demonstrated, combining two consecutive click reactions of azide-alkyne cycloaddition of linear hetero-bifunctional precursors and thiol-ene coupling for post cyclization functionalizations. Functional cationic and thermo-responsive cyclic polyphosphoesters have been synthesized to demonstrate the efficiency of the procedures.

  11. Covalent protein-oligonucleotide conjugates by copper-free click reaction. (United States)

    Khatwani, Santoshkumar L; Kang, Jun Sung; Mullen, Daniel G; Hast, Michael A; Beese, Lorena S; Distefano, Mark D; Taton, T Andrew


    Covalent protein-oligodeoxynucleotide (protein-ODN) conjugates are useful in a number of biological applications, but synthesizing discrete conjugates-where the connection between the two components is at a defined location in both the protein and the ODN-under mild conditions with significant yield can be a challenge. In this article, we demonstrate a strategy for synthesizing discrete protein-ODN conjugates using strain-promoted azide-alkyne [3+2] cycloaddition (SPAAC, a copper-free 'click' reaction). Azide-functionalized proteins, prepared by enzymatic prenylation of C-terminal CVIA tags with synthetic azidoprenyl diphosphates, were 'clicked' to ODNs that had been modified with a strained dibenzocyclooctyne (DIBO-ODN). The resulting protein-ODN conjugates were purified and characterized by size-exclusion chromatography and gel electrophoresis. We find that the yields and reaction times of the SPAAC bioconjugation reactions are comparable to those previously reported for copper-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) bioconjugation, but require no catalyst. The same SPAAC chemistry was used to immobilize azide-modified proteins onto surfaces, using surface-bound DIBO-ODN as a heterobifunctional linker. Cu-free click bioconjugation of proteins to ODNs is a simple and versatile alternative to Cu-catalyzed click methods.

  12. Copper-free 'click' : 1,3-dipolar cycloaddition of azides and arynes

    NARCIS (Netherlands)

    Campbell-Verduyn, Lachlan; Elsinga, Philip H.; Mirfeizi, Leila; Dierckx, Rudi A.; Feringa, Ben L.


    Arynes formed through fluoride-promoted ortho-elimination of o-(trimethylsilyl)aryl triflates can undergo [3 + 2] cycloaddition with various azides to form substituted benzotriazoles. The rapid reaction times and mild conditions make this an attractive variation of the classical 'click' reaction of

  13. Specific surface modification of the acetylene-linked glycolipid vesicle by click chemistry. (United States)

    Ito, Hidehiro; Kamachi, Toshiaki; Yashima, Eiji


    A novel glycolipid with a terminal acetylene was synthesized and used to prepare unilamellar vesicles. Using these vesicles, a convenient method was developed for the specific modification of the vesicle surface using the photoresponsive copper complex [Cu(OH(2))(cage)] as the catalyst for a click reaction.

  14. Towards copper-free nanocapsules obtained by orthogonal interfacial "click" polymerization in miniemulsion. (United States)

    Siebert, Joerg Max; Baier, Grit; Musyanovych, Anna; Landfester, Katharina


    A facile method to produce nanocapsules by copper-free interfacial "click"-polymerization as orthogonal reaction for the encapsulation of functional molecules is successfully performed using stable miniemulsion droplets. Difunctional azides and alkynes have been used for polymerization around the miniemulsion droplets, leading to the formation of nanocapsules. The results were compared with copper-catalyzed systems.

  15. Effect of external pressure environment on the internal noise level due to a source inside a cylindrical tank (United States)

    Clevenson, S. A.; Roussos, L. A.


    A small cylindrical tank was used to study the effect on the noise environment within a tank of conditions of atmospheric (sea level) pressure or vacuum environments on the exterior. Experimentally determined absorption coefficients were used to calculate transmission loss, transmissibility coefficients and the sound pressure (noise) level differences in the interior. The noise level differences were also measured directly for the two exterior environments and compared to various analytical approximations with limited agreement. Trend study curves indicated that if the tank transmission loss is above 25 dB, the difference in interior noise level between the vacuum and ambient pressure conditions are less than 2 dB.

  16. 129I and its species in the East China Sea: level, distribution, sources and tracing water masses exchange and movement

    DEFF Research Database (Denmark)

    Liu, Dan; Hou, Xiaolin; Du, Jinzhou;


    , and 129I level in seawater declines towards the ECS shelf. In the open sea, 129I and 127I in surface water exists mainly as iodate, while in Yangtze River estuary and some locations, iodide is dominated. The results indicate that the Fukushima nuclear accident has no detectable effects in the ECS until...... and their inorganic chemical species in the first time. The measured 129I/127I ratio is 1–3 orders of magnitude higher than the pre-nuclear level, indicating its dominantly anthropogenic sources. Relatively high 129I levels were observed in the Yangtze River and its estuary, as well as in the southern Yellow Sea...

  17. 点击化学最新进展%Advances in Click Chemistry

    Institute of Scientific and Technical Information of China (English)

    邱素艳; 高森; 林振宇; 陈国南


    点击化学(click chemistry)是由2001年诺贝尔化学奖获得者美国化学家Sharpless首次提出.最主要的一类点击化学反应是Cu(I)化合物催化叠氮化合物与炔基化合物反应生成1,2,3-三唑五元环化合物,它能够将两种不同物质通过五元环共价结合起来.该方法具备产量高、效率高、副反应少、反应条件温和、分离提纯简单、环境污染小等优点,因此得到了广泛的应用.目前点击化学的发展极为迅速,涉及到了各个领域,特别是在功能聚合物、表面修饰、生物大分子、DNAs,生物与化学传感器等方面取得了瞩目的成就.本文论述了点击化学反应的基本概念、特点及优势,对近几年点击化学的发展状况,以及一些最新研究成果作一简要概述,并展望了点击化学的发展前景.%Click chemistry, a new molecular approach proposed by Sharpless and co-workers in 2001, is the most practical and reliable chemical reactions to connect a diversity of structures. The Cu ( Ⅰ ) catalyzed azidealkyne 1,3-dipolar cycloaddition is one of the most common reactions in click chemistry, which has high yield,good efficiency, and high purity. In addition, this click reaction is essentially inert to most biological molecules,oxygen, water, and tolerant of a wide range of solvents, pH values and temperatures, and allows mild reaction conditions. This click reaction also has excellent selectivity in chemical synthesis. Owing to the fact that the azide and alkyne groups are facile introduced in the structure of molecules and form a stable 1,2,3-trizoles via click reaction, it has been widely applied in syntheses of functional polymers and biomacromolecules, surfaces modification, functionalization of DNAs and carbon nanotubes, and it has been also widely used for fabrication of biological or chemical sensors. In recent years, the cells and viruses have been modified by using click chemistry,while it doesn't damage the cells and

  18. History of click-speaking populations of Africa inferred from mtDNA and Y chromosome genetic variation. (United States)

    Tishkoff, Sarah A; Gonder, Mary Katherine; Henn, Brenna M; Mortensen, Holly; Knight, Alec; Gignoux, Christopher; Fernandopulle, Neil; Lema, Godfrey; Nyambo, Thomas B; Ramakrishnan, Uma; Reed, Floyd A; Mountain, Joanna L


    Little is known about the history of click-speaking populations in Africa. Prior genetic studies revealed that the click-speaking Hadza of eastern Africa are as distantly related to click speakers of southern Africa as are most other African populations. The Sandawe, who currently live within 150 km of the Hadza, are the only other population in eastern Africa whose language has been classified as part of the Khoisan language family. Linguists disagree on whether there is any detectable relationship between the Hadza and Sandawe click languages. We characterized both mtDNA and Y chromosome variation of the Sandawe, Hadza, and neighboring Tanzanian populations. New genetic data show that the Sandawe and southern African click speakers share rare mtDNA and Y chromosome haplogroups; however, common ancestry of the 2 populations dates back >35,000 years. These data also indicate that common ancestry of the Hadza and Sandawe populations dates back >15,000 years. These findings suggest that at the time of the spread of agriculture and pastoralism, the click-speaking populations were already isolated from one another and are consistent with relatively deep linguistic divergence among the respective click languages.

  19. A New Methodology for Assessing Macromolecular Click Reactions and Its Application to Amine--Tertiary Isocyanate Coupling for Polymer Ligation. (United States)

    Gody, Guillaume; Roberts, Derrick A; Maschmeyer, Thomas; Perrier, Sébastien


    Click reactions have provided access to an array of remarkably complex polymer architectures. However, the term "click" is often applied inaccurately to polymer ligation reactions that fail to respect the criteria that typify a true "click" reaction. With the purpose of providing a universal way to benchmark polymer-polymer coupling efficiency at equimolarity and thus evaluate the fulfilment of click criteria, we report a simple one-pot methodology involving the homodicoupling of α-end-functionalized polymers using a small-molecule bifunctional linker. A combination of SEC analysis and chromatogram deconvolution enables straightforward quantification of the coupling efficiency. We subsequently employ this methodology to evaluate an overlooked candidate for the click reaction family: the addition of primary amines to α-tertiary isocyanates (α-(t)NCO). Using our bifunctional linker coupling strategy, we show that the amine-(t)NCO reaction fulfills the criteria for a polymer-polymer click reaction, achieving rapid, chemoselective, and quantitative coupling at room temperature without generating any byproducts. We demonstrate that amine-(t)NCO coupling is faster and more efficient than the more common amine-tertiary active ester coupling under equivalent conditions. Additionally, we show that the α-(t)NCO end group is unprecedentedly stable in aqueous media. Thus, we propose that the amine-(t)NCO ligation is a powerful new click reaction for efficient macromolecular coupling.

  20. Effect of non-phytate phosphorus levels and phytase sources on the growth performance, serum biochemical and tibial parameters of broiler chickens

    Directory of Open Access Journals (Sweden)

    Xian R. Jiang


    Full Text Available A 3×3 fattorial arrangement with dietary non-phytate phosphorus (NPP levels and phytase sources (3- and 6-phytase was conducted to evaluate the effects of NPP levels, phytase sources and their possible interactions on growth performance, serum biochemical and tibia parameters of broiler chickens from hatch to 42 days of age. A total of 540 1-day-old Arbor Acres male broiler chicks were randomly allocated into nine dietary treatments, each containing 5 replicates pens with 12 birds per pen. Interaction was statistically significant in the performance till day 21 of trial, supplementation of low NPP diet decreased body weight (BW (P<0.001, depressed average daily gain (ADG (P<0.001 and deteriorated average daily feed intake (ADFI (P<0.001 over day 42. During the 8-to-21-day period, even if interaction between NPP levels and phytase sources was significant (P<0.01, BW, ADG and ADFI always increased due to dietary supplementation of phytase, with source not differing. Dietary high NPP enhanced serum calcium and P concentrations on day 21 and 42 (linear contrast, P<0.01, while decreased alkaline phosphatase (AKP activity on day 42 (linear contrast, P<0.001, and interaction was not significant. Both dietary sources of phytase decreased serum AKP activities on day 42 (P<0.001, and urea nitrogen content on day 21 (P<0.01 and 42 (P<0.001. Both phytase improved ash percentage on day 21 and P content in tibia at 21 and 42 days of age (P<0.001. The results confirmed that dietary supplementation of phytase may enhance P availability during the 8-to-21-day period. Nevertheless, no difference between the two phytase sources was observed.

  1. Deep Multimodal Distance Metric Learning Using Click Constraints for Image Ranking. (United States)

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


    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.

  2. PBDEs and other POPs in urban birds of prey partly explained by trophic level and carbon source

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, John E. [Environment Canada, Science & Technology Branch, Pacific Wildlife Research Centre, Delta, British Columbia V4K 3N2 (Canada); Department of Biological Science, Simon Fraser University, Burnaby, BC V5A 1S6 (Canada); Brogan, Jason [Department of Biological Science, Simon Fraser University, Burnaby, BC V5A 1S6 (Canada); Lee, Sandi L. [Environment Canada, Science & Technology Branch, Pacific Wildlife Research Centre, Delta, British Columbia V4K 3N2 (Canada); Drouillard, Ken G. [Great Lakes Institute for Environmental Research, University of Windsor, Windsor, ON N9B 3P4 (Canada); Elliott, Kyle H. [Department of Natural Resource Sciences, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9 (Canada)


    As urban sprawl and agricultural intensification continue to invade prime wildlife habitat, some animals, even apex predators, are managing to adapt to this new environment. Chemical pollution is one of many stressors that wildlife encounter in urban environments. Predators are particularly sensitive to persistent chemical pollutants because they feed at a high trophic level where such pollution is biomagnified. To examine levels of pollution in urban birds of prey in the Lower Mainland region of British Columbia, Canada, we analyzed persistent organic contaminants in adult birds found dead of trauma injury. The hepatic geometric mean concentration of sum polybrominated diphenyl ethers (∑PBDEs) in 13 Cooper's hawks (Accipiter cooperii) from Greater Vancouver was 1873 ng/g (lipid weight) with one bird reaching 197,000 ng/g lipid weight, the highest exposure reported to date for a wild bird. Concentrations of ∑PBDEs, ∑PCBs (polychlorinated biphenyls) and, surprisingly, cyclodiene insecticides were greatest in the urban environment while those of DDE (1,1-dichloroethylene bis[p-chlorophenyl) were highest in a region of intensive agriculture. The level of most chlorinated and brominated contaminants increased with trophic level (δ{sup 15}N). The concentrations of some contaminants, PBDEs in particular, in these birds of prey may have some toxicological consequences. Apex predators in urban environments continue to be exposed to elevated concentrations of legacy pollutants as well as more recent brominated pollutants. - Highlights: • As urban areas expand, many animal species are adapting and invading urban areas. • Urban colonists encounter many new stressors, especially chemical pollution. • Urban birds of prey in Canada had high levels of brominated flame retardants (PBDEs). • One individual had the highest level of PBDEs ever recorded for wildlife. • Such high levels may have had toxicological implications.

  3. Low level impurities in imported wheat are a likely source of feral transgenic oilseed rape (Brassica napus L.) in Switzerland


    Schulze, Juerg; Brodmann, Peter; Oehen, Bernadette; Bagutti, Claudia


    In Switzerland, the cultivation of genetically modified (GM) oilseed rape (Brassica napus L.) and the use of its seeds for food and feed are not permitted. Nevertheless, the GM oilseed rape events GT73, MS8×RF3, MS8 and RF3 have recently been found in the Rhine port of Basel, Switzerland. The sources of GM oilseed rape seeds have been unknown. The main agricultural good being imported at the Rhine port of Basel is wheat and from 2010 to 2013, 19 % of all Swiss wheat imports originated from Ca...

  4. Duration-tunable picosecond source at 560  nm with watt-level average power. (United States)

    Runcorn, T H; Murray, R T; Kelleher, E J R; Popov, S V; Taylor, J R


    A pulse source at 560 nm that is tunable in duration between 50 ps and 2.7 ns with >1  W of average power and near diffraction-limited beam quality is demonstrated. The source is based on efficient (up to 50%) second-harmonic generation in a periodically poled lithium tantalate crystal of a linearly polarized fiber-integrated Raman amplifier operating at 1120 nm. A duration-tunable ytterbium master-oscillator power-fiber amplifier is used to pulse-pump the Raman amplifier, which is seeded by a continuous-wave distributed-feedback laser diode at 1120 nm. The performance of the system using two different master oscillator schemes is compared. A pulse energy of up to 765 nJ is achieved with a conversion efficiency of 25% from the ytterbium fiber pump, demonstrating a compact and turn-key architecture for obtaining high peak-power radiation at 560 nm.

  5. Levels, sources and chemical fate of persistent organic pollutants in the atmosphere and snow along the western Antarctic Peninsula. (United States)

    Khairy, Mohammed A; Luek, Jenna L; Dickhut, Rebecca; Lohmann, Rainer


    The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October-November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier's snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were mainly found in the vapor phase (>65%). Hexachlorobenzene (33.6 pg/m(3)), PCBs (11.6 pg/m(3)), heptachlor (5.64 pg/m(3)), PBDEs (4.22 pg/m(3)) and cis-chlordane (2.43 pg/m(3)) were the most abundant contaminants. In contrast to other compounds, PBDEs seem to have originated from local sources, possibly the research station itself. Gas-particle partitioning for analytes were better predicted using the adsorption partitioning model than an octanol-based absorption approach. Diffusive flux calculations indicated that net deposition is the dominant pathway for PBDEs and chlordanes, whereas re-volatilization from snow (during melting or metamorphosis) was observed for PCBs and some OCPs.

  6. Persistent toxic substances in remote lake and coastal sediments from Svalbard, Norwegian Arctic: levels, sources and fluxes. (United States)

    Jiao, Liping; Zheng, Gene J; Minh, Tu Binh; Richardson, Bruce; Chen, Liqi; Zhang, Yuanhui; Yeung, Leo W; Lam, James C W; Yang, Xulin; Lam, Paul K S; Wong, Ming H


    Surface sediments from remote lakes and coastal areas from Ny-Alesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Alesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Alesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies.

  7. Liver is the major source of elevated serum lipocalin-2 levels after bacterial infection or partial hepatectomy

    DEFF Research Database (Denmark)

    Xu, Ming-Jiang; Feng, Dechun; Wu, Hailong;


    knockout (Lcn2(Hep-/-)) mice were generated and subjected to bacterial infection (with Klesbsiella pneumoniae or Escherichia coli) or partial hepatectomy (PHx). Studies of Lcn2(Hep-/-) mice revealed that hepatocytes contributed to 25% of the low basal serum level of LCN2 protein (∼ 62 ng/mL) but were...... responsible for more than 90% of the highly elevated serum LCN2 protein level (∼ 6,000 ng/mL) postinfection and more than 60% post-PHx (∼ 700 ng/mL). Interestingly, both Lcn2(Hep-/-) and global Lcn2 knockout (Lcn2(-/-)) mice demonstrated comparable increases in susceptibility to infection with K. pneumoniae...

  8. Metal uptake of tomato and alfalfa plants as affected by water source, salinity, and Cd and Zn levels under greenhouse conditions. (United States)

    Gharaibeh, Mamoun A; Marschner, Bernd; Heinze, Stefanie


    Irrigation with wastewater is a promising option to improve crop yields and to reduce pressure on freshwater sources. However, heavy metal concentrations in wastewater may cause health concerns. A greenhouse pot experiment was conducted in order to determine cadmium (Cd) and zinc (Zn) concentrations in sandy soil and plant tissues of tomato (Lycopersicon esculentum L.) and alfalfa (Medicago sativa L.). A 2 × 2 × 4 × 2 factorial treatment arrangement was utilized. Two water sources, fresh (FW) or treated wastewater (TWW), at two salinity levels (1 and 3 dS m(-1)) containing different levels of Cd and Zn were used. Samples were collected after a 90-day growth period. It was observed that the growth of both plants was depressed at the highest metal level (L3). Metal accumulation in plant parts increased with the increase of metal concentration and salinity in irrigation water. At low salinity, water source was the main factor which controlled metal accumulation, whereas, at high salinity, chloride appeared to be the principal factor controlling metal uptake regardless of water source. Metal translocation from roots to shoots increased in TWW-irrigated plants, even in the controls. Tomatoes accumulated Cd up to and above critical levels safe for human consumption, even though Cd concentration in irrigation water did not exceed the current recommended values. Therefore, food production in sandy soils may well pose a health hazard when irrigated with TWW containing heavy metals. Complexation with dissolved organic compounds (DOC) in TWW may be to be the principal factor responsible for increased metal uptake and transfer at low salinity, thereby increasing the risk of heavy metal contamination of food and forage crops.

  9. Source inventory for Department of Energy solid low-level radioactive waste disposal facilities: What it means and how to get one of your own

    Energy Technology Data Exchange (ETDEWEB)

    Smith, M.A. [Science Applications International Corp., Oak Ridge, TN (United States). Environmental Compliance Group


    In conducting a performance assessment for a low-level waste (LLW) disposal facility, one of the important considerations for determining the source term, which is defined as the amount of radioactivity being released from the facility, is the quantity of radioactive material present. This quantity, which will be referred to as the source inventory, is generally estimated through a review of historical records and waste tracking systems at the LLW facility. In theory, estimating the total source inventory for Department of Energy (DOE) LLW disposal facilities should be possible by reviewing the national data base maintained for LLW operations, the Solid Waste Information Management System (SWIMS), or through the annual report that summarizes the SWIMS data, the Integrated Data Base (IDB) report. However, in practice, there are some difficulties in making this estimate. This is not unexpected, since the SWIMS and the IDB were not developed with the goal of developing a performance assessment source term in mind. The practical shortcomings using the existing data to develop a source term for DOE facilities will be discussed in this paper.

  10. Persistent toxic substances in remote lake and coastal sediments from Svalbard, Norwegian Arctic: Levels, sources and fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Jiao Liping [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, 178 Daxue Road, Xiamen, Fijian (China); Third Institute of Oceanography, State Oceanic Administration, 178 Daxue Road, Xiamen, Fujian (China); Zheng, Gene J. [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong (China); Minh, Tu Binh; Richardson, Bruce [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Chen Liqi; Zhang Yuanhui [Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, 178 Daxue Road, Xiamen, Fijian (China); Third Institute of Oceanography, State Oceanic Administration, 178 Daxue Road, Xiamen, Fujian (China); Yeung, Leo W.; Lam, James C.W. [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China); Yan, Xulin [Key Laboratory of Global Change and Marine-Atmospheric Chemistry, State Oceanic Administration, 178 Daxue Road, Xiamen, Fijian (China); Third Institute of Oceanography, State Oceanic Administration, 178 Daxue Road, Xiamen, Fujian (China); Lam, Paul K.S. [Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)], E-mail:; Wong, Ming H. [Croucher Institute for Environmental Sciences, Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong (China)], E-mail:


    Surface sediments from remote lakes and coastal areas from Ny-Alesund, Svalbard, Norwegian Arctic were analyzed for polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). Relatively high levels of PAHs were encountered from several lakes from Ny-Alesund, which were within the range of levels reported for European high mountain lakes and some urban/industrialized areas in the world, pointing to the role of remote Arctic lakes as potential reservoir of semi-volatile organic compounds. Specific patterns of PBDEs were observed, showing higher concentrations of lower brominated compounds such as BDE-7, 17 and 28. Estimated surface sediment fluxes of PAHs in Ny-Alesund remote lakes were similar to those observed for some European high mountain lakes. The current PAH levels in sediments from three lakes exceeded Canadian sediment quality guidelines, suggesting the presence of possible risks for aquatic organisms and the need for further studies. - High levels of PAHs and specific patterns of PBDEs were found in sediments from the remote Norwegian Arctic lakes.

  11. Population-level consequences of herbivory, changing climate, and source-sink dynamics on a long-lived invasive shrub. (United States)

    van Klinken, R D; Pichancourt, J B


    Long-lived plant species are highly valued environmentally, economically, and socially, but can also cause substantial harm as invaders. Realistic demographic predictions can guide management decisions, and are particularly valuable for long-lived species where population response times can be long. Long-lived species are also challenging, given population dynamics can be affected by factors as diverse as herbivory, climate, and dispersal. We developed a matrix model to evaluate the effects of herbivory by a leaf-feeding biological control agent released in Australia against a long-lived invasive shrub (mesquite, Leguminoseae: Prosopis spp.). The stage-structured, density-dependent model used an annual time step and 10 climatically diverse years of field data. Mesquite population demography is sensitive to source-sink dynamics as most seeds are consumed and redistributed spatially by livestock. In addition, individual mesquite plants, because they are long lived, experience natural climate variation that cycles over decadal scales, as well as anthropogenic climate change. The model therefore explicitly considered the effects of both net dispersal and climate variation. Herbivory strongly regulated mesquite populations through reduced growth and fertility, but additional mortality of older plants will be required to reach management goals within a reasonable time frame. Growth and survival of seeds and seedlings were correlated with daily soil moisture. As a result, population dynamics were sensitive to rainfall scenario, but population response times were typically slow (20-800 years to reach equilibrium or extinction) due to adult longevity. Equilibrium population densities were expected to remain 5% higher, and be more dynamic, if historical multi-decadal climate patterns persist, the effect being dampened by herbivory suppressing seed production irrespective of preceding rainfall. Dense infestations were unlikely to form under a drier climate, and required net

  12. Effect of Different Oil Sources on Muscle Fatty Acid Composition and Serum Lipoproteins Levels in Sarabi Beef Steer

    Directory of Open Access Journals (Sweden)

    Mohamad Golshan-Zoroofi


    Full Text Available This study examined the effects of different vegetable oil sources on the Fatty Acid (FA composition of muscle and performance of beef steer (Sarabi strain. Twenty one steers (384±17 kg BW were assigned in seven treatment that fed diets containing 0% oil (control, 2 and 4% of Canola Oil (CO, Sunflower Oil (SO and Restaurant Waste Oils (RWO. Ribeye steaks from steers fed CO, SO and RWO for 90 days of experiment were used after slaughtering to evaluate the effects of oil source on fatty acid composition. Amounts of muscle saturated FAs decreased and polyunsaturated FAs increased in both 2% CO and 2% SO groups. The highest contents of total n-3, n-6 and n-7 FAs were significantly (p<0.05 obtained with 2% CO, 2% SO and control groups, respectively. Animals fed 2% CO had the lowest content of total n-9 FAs in compared to other groups. Control and 2% SO dietary groups presented lowest total cholesterol and 4% CO group resulted in a lowest triglycerides (p<0.01. The high and low-density lipoprotein (HDL and LDL was highest in 2 and 4% RWO group, respectively and animals fed 4% SO and 4% CO had the lowest LDL and very low-DL (VLDL, respectively. Control animals and those fed 2% oils tended to have higher dry matter intake (DMI, <0.05. The best Daily Weight Gain (DWG was related to 2% RWO dietary group and followed by 2% SO dietary groups; however, differences were not significant.

  13. Click on silica: systematic immobilization of Co(II) Schiff bases to the mesoporous silica via click reaction and their catalytic activity for aerobic oxidation of alcohols. (United States)

    Rana, Bharat S; Jain, Suman L; Singh, Bhawan; Bhaumik, Asim; Sain, Bir; Sinha, Anil K


    The systematic immobilization of cobalt(II) Schiff base complexes on SBA-15 mesoporous silica via copper catalyzed [3 + 2] azide-alkyne cycloaddition (CuAAC) "click reaction" involving either step-wise synthesis of silica-bound Schiff base ligand followed by its subsequent complexation with cobalt ions, or by the direct immobilization of preformed Co(II) Schiff base complex to the silica support is described. The catalytic activity of the prepared complexes was studied for the oxidation of alcohols to carbonyl compounds using molecular oxygen as oxidant. The immobilized complexes were recycled for several runs without loss in catalytic activity and no leaching was observed during this course.

  14. High-density DNA functionalization by a combination of Cu-catalyzed and cu-free click chemistry. (United States)

    Gutsmiedl, Katrin; Fazio, Danila; Carell, Thomas


    We report the regioselective Cu-free click modification of styrene functionalized DNA with nitrile oxides. A series of modified oligodeoxynucleotides (nine base pairs) was prepared with increasing styrene density. 1,3-Dipolar cycloaddition with nitrile oxides allows the high density functionalization of the styrene modified DNA directly on the DNA solid support and in solution. This click reaction proceeds smoothly even directly in the DNA synthesizer and gives exclusively 3,5-disubstituted isoxazolines. Additionally, PCR products (300 and 900 base pairs) were synthesized with a styrene triphosphate and KOD XL polymerase. The click reaction on the highly modified PCR fragments allows functionalization of hundreds of styrene units on these large DNA fragments simultaneously. Even sequential Cu-free and Cu-catalyzed click reaction of PCR amplicons containing styrene and alkyne carrying nucleobases was achieved. This new approach towards high-density functionalization of DNA is simple, modular, and efficient.

  15. Correlation of lithium levels between drinking water obtained from different sources and scalp hair samples of adult male subjects. (United States)

    Baloch, Shahnawaz; Kazi, Tasneem Gul; Afridi, Hassan Imran; Baig, Jameel Ahmed; Talpur, Farah Naz; Arain, Muhammad Balal


    There is some evidence that natural levels of lithium (Li) in drinking water may have a protective effect on neurological health. In present study, we evaluate the Li levels in drinking water of different origin and bottled mineral water. To evaluate the association between lithium levels in drinking water with human health, the scalp hair samples of male subjects (25-45 years) consumed drinking water obtained from ground water (GW), municipal treated water (MTW) and bottled mineral water (BMW) from rural and urban areas of Sindh, Pakistan were selected. The water samples were pre-concentrated five to tenfold at 60 °C using temperature-controlled electric hot plate. While scalp hair samples were oxidized by acid in a microwave oven, prior to determined by flame atomic absorption spectrometry. The Li content in different types of drinking water, GW, MTW and BMW was found in the range of 5.12-22.6, 4.2-16.7 and 0.0-16.3 µg/L, respectively. It was observed that Li concentration in the scalp hair samples of adult males consuming ground water was found to be higher, ranged as 292-393 μg/kg, than those who are drinking municipal treated and bottle mineral water (212-268 and 145-208 μg/kg), respectively.

  16. Observation of the controlled assembly of preclick components in the in situ click chemistry generation of a chitinase inhibitor


    Hirose, T.; Maita, N; Gouda, H.; Koseki, J; Yamamoto, T; Sugawara, A; H. Nakano; Hirono, S; Shiomi, K.; Watanabe, T; Taniguchi, H; Sharpless, KB; Omura, S; Sunazuka, T


    Several in situ click chemistry studies have been reported. To date, there is evidence to indicate that proteins act as mold between azide and alkyne fragments by X-ray analysis of protein–ligand complexes. However, only “postclick” structural evidence has been available. We succeeded in obtaining crystal structures of a chitinase complexed with an azide inhibitor and an O-allyl oxime fragment as a mimic of a click partner, revealing a mechanism for accelerating triazole formation in chitinas...

  17. Vertical-aware click model-based effectiveness metrics

    NARCIS (Netherlands)

    I. Markov; E. Kharitonov; V. Nikulin; P. Serdyukov; M. de Rijke; F. Crestani


    Today's web search systems present users with heterogeneous information coming from sources of different types, also known as verticals. Evaluating such systems is an important but complex task, which is still far from being solved. In this paper we examine the hypothesis that the use of models that

  18. The contribution of wood burning and other pollution sources to wintertime organic aerosol levels in two Greek cities (United States)

    Florou, Kalliopi; Papanastasiou, Dimitrios K.; Pikridas, Michael; Kaltsonoudis, Christos; Louvaris, Evangelos; Gkatzelis, Georgios I.; Patoulias, David; Mihalopoulos, Nikolaos; Pandis, Spyros N.


    The composition of fine particulate matter (PM) in two major Greek cities (Athens and Patras) was measured during two wintertime campaigns, one conducted in 2013 and the other in 2012. A major goal of this study is to quantify the sources of organic aerosol (OA) and especially residential wood burning, which has dramatically increased due to the Greek financial crisis. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) was deployed at both sites. PM with diameter less than 1 µm (PM1) consisted mainly of organics (60-75 %), black carbon (5-20 %), and inorganic salts (around 20 %) in both Patras and Athens. In Patras, during evening hours, PM1 concentrations were as high as 100 µg m-3, of which 85 % was OA. In Athens, the maximum hourly value observed during nighttime was 140 µg m-3, of which 120 µg m-3 was OA. Forty to 60 % of the average OA was due to biomass burning for both cities, while the remaining mass originated from traffic (12-17 %), cooking (12-16 %), and long-range transport (18-24 %). The contribution of residential wood burning was even higher (80-90 %) during the nighttime peak concentration periods, and less than 10 % during daytime. Cooking OA contributed up to 75 % during mealtime hours in Patras, while traffic-related OA was responsible for 60-70 % of the OA during the morning rush hour.

  19. Comparative proteomic analysis of Aureobasidium pullulans in the presence of high and low levels of nitrogen source. (United States)

    Sheng, Long; Zhu, Guilan; Tong, Qunyi


    Pullulan, produced by Aureobasidium pullulans strain, has been broadly used in the food and medical industries. However, relatively little is known concerning the molecular basis of pullulan biosynthesis of this strain. In this paper, the effect of different concentrations of (NH4)2SO4 on pullulan fermentation was studied. Proteomics containing two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) were used to analyze the protein with different expressions of A. pullulans cells between the nitrogen limitation and nitrogen repletion. Maximum pullulan production reached 37.72 g/L when 0.6 g/L of initial (NH4)2SO4 was added. Excess nitrogen source would impel carbon flux flow toward biomass production, but decreased the pullulan production. Nitrogen limitation in A. pullulans seemed to influence the flux change of carbon flux flow toward exopolysaccharide accumulation. The findings indicated that 12 identified protein spots were involved in energy-generating enzymes, antioxidant-related enzymes, amino acid biosynthesis, glycogen biosynthesis, glycolysis, protein transport, and transcriptional regulation. These results presented more evidence of pullulan biosynthesis under nitrogen-limited environment, which would provide a molecular understanding of the physiological response of A. pullulans for optimizing the performance of industrial pullulan fermentation.

  20. Noise levels and sources in the Stellwagen Bank National Marine Sanctuary and the St. Lawrence River Estuary


    Scheifele, Peter M.; Darre, Michael


    Although ambient (background) noise in the ocean is a topic that has been widely studied since pre-World War II, the effects of noise on marine organisms has only been a focus of concern for the last 25 years. The main point of concern has been the potential of noise to affect the health and behavior of marine mammals. The Stellwagen Bank National Marine Sanctuary (SBNMS) is a site where the degradation of habitat due to increasing noise levels is a concern because it is a feeding groun...

  1. A Five-Level Cascade Multilever Invertor Three-Phase Motor Drive Using a Single DC Source

    Energy Technology Data Exchange (ETDEWEB)

    Chiasson, J.N. (Univ. Tennessee-Knoxville)


    A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet synchronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obtained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.

  2. A Five-Level Cascade Multilevel Inverter Three-Phase Motor Drive Using a Single DC Source

    Energy Technology Data Exchange (ETDEWEB)

    Chiasson, J. N. [University of Tennessee, Knoxville (UTK)


    A method is presented showing that a 5-level cascade multilevel inverter for a three-phase permanent magnet sychronous motor drive can be implemented using only a single DC link to supply a standard 3-leg inverter along with three full H-bridges supplied by capacitors. It is shown that the capacitor voltages can be regulated while achieving an output voltage waveform that is 20% greater than that obained using the standard 3-leg inverter alone. Finally conditions are given in terms of the power factor and modulation index that determine when the capacitor voltage can regulated.

  3. Disappearance of click-evoked potentials on the neck of the guinea pig by pharmacological and surgical destruction of the peripheral vestibular afferent system. (United States)

    Matsuzaki, Masaki; Murofushi, Toshihisa


    In order to establish an animal model of acoustically evoked vestibulo-collic reflex, the so-called vestibular evoked myogenic potential in humans, potentials evoked by loud clicks on the neck of the guinea pig were recorded using subjects whose peripheral vestibular endorgans or vestibular afferents had been damaged. Four normal control guinea pigs, four guinea pigs that received an intramuscular injection of gentamicin for 20 days (90 mg/kg/day) and five guinea pigs whose vestibular nerves were surgically sectioned were used in this study. Under general anesthesia with an intraperitoneal injection of pentobarbital sodium (40 mg/kg), auditory brainstem responses (ABRs) were recorded. Then, potentials evoked by loud clicks on the pre-vertebral muscle at the level of the third cervical vertebral bone were recorded using silver ball electrodes. As a result, a distinctive negative peak (NP) with a latency of 6-8 ms was recorded in all animals in the control group. NP was not observed in the gentamicin-administered group while ABR was preserved. After sectioning the vestibular nerve, NP was abolished while ABR was preserved. From these results, NP could be of vestibular origin. These results are in agreement with a previous report of NP using subjects whose cochlea had been damaged pharmacologically.

  4. Single "click" synthesis of a mixed-mode silica sorbent and application in matrix solid-phase dispersion extraction of β-agonists from porcine liver. (United States)

    Zhu, Yuling; Yang, Siwen; Chen, Gang; Xing, Jun


    A single "click" strategy is proposed for the preparation of a reversed-phase/weak cation-exchange mixed-mode silica-based sorbent (silica-WCX). Upon this strategy, both 1-dodecyne and 5-hexynoic acid were simultaneously immobilized onto azide-silica in varied ratio via Cu (I)-catalyzed azide-alkyne cycloaddition click reaction. The chemical compositions of silica-WCXs were characterized by elemental analysis, acid-base titration and Fourier transform-infrared spectroscopy. The results indicated that the actual mole ratio of n-dodecyl to carboxylic group on the sorbent is almost the same as the reactant ratio of 1-dodecyne to 5-hexynoic acid, and the repeatability of synthesis method is good. After that, two β-agonists, clenbuterol and ractopamine, were selected as model drug residues to evaluate the applicability of silica-WCX in matrix solid-phase dispersion extraction for the determination of basic drug residues in porcine liver by HPLC/UV. In comparison with some commercial sorbents, silica-WCX exhibited higher recoveries and better purification capability. Under the optimized conditions, linearity ranges were between 0.04 and 8.0μg/g for both analytes with coefficients of determination (R(2)) higher than 0.9997. The average recoveries at three spiked levels ranged from 92.5% to 105.0% with RSDs less than 6.6%.

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

    KAUST Repository

    Gerrard, Simon R.


    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.

  6. Instantaneous Click Chemistry by a Copper-Containing Polymeric-Membrane-Installed Microflow Catalytic Reactor. (United States)

    Yamada, Yoichi M A; Ohno, Aya; Sato, Takuma; Uozumi, Yasuhiro


    The copper(I)-catalyzed Huisgen cycloaddition (azide-alkyne cycloaddition) is an important reaction in click chemistry that ideally proceeds instantaneously. An instantaneous Huisgen cycloaddition has been developed that uses a novel catalytic dinuclear copper complex-containing polymeric membrane-installed microflow device. A polymeric membranous copper catalyst was prepared from poly(4-vinylpyridine), copper(II) sulfate, sodium chloride, and sodium ascorbate at the interface of two laminar flows inside microchannels. Elucidation of the structure by XANES, EXAFS, and elemental analysis, as well as second-order Møller-Plesset perturbation theory (MP2) calculations and density functional theory (DFT) calculations assigned the local structure near Cu as a μ-chloro dinuclear Cu(I) complex. The microflow device promotes the instantaneous click reaction of a variety of alkynes and organic azides to afford the corresponding triazoles in quantitative yield.

  7. Application of click chemistry conditions for 5-bromo-2'-deoxyuridine determination through Fenton and related reactions. (United States)

    Cappella, Paolo; Pulici, Maurizio; Gasparri, Fabio


    Mixtures of ascorbate and copper used in certain click chemistry experimental conditions act as oxidizing agents, catalyzing the formation of reactive oxygen species through Fenton and related reactions. Hydroxyl radicals act as chemical nucleases, introducing DNA strand breaks that can be exploited for BrdU immunostaining in place of acid denaturation. This procedure is readily applicable to high content analysis and flow cytometry assays, and provides results comparable to click chemistry EdU cycloaddition and classical BrdU immunodetection. Importantly, this approach allows preservation of labile epitopes such as phosphoproteins. This unit describes an optimized method that successfully employs Fenton chemistry for simultaneous detection of phosphoproteins and BrdU in intact cells.

  8. Ultramild protein-mediated click chemistry creates efficient oligonucleotide probes for targeting and detecting nucleic acids

    DEFF Research Database (Denmark)

    Nåbo, Lina J.; Madsen, Charlotte Stahl; Jensen, Knud Jørgen


    results by electronic structure calculations. Functionalized oligonucleotides were prepared in good yields by protein-mediated CuAAC click reactions for the first time with a human copper-binding chaperon. The carbohydrate, peptide, and fluorescent derivatives display high binding affinity and selectivity...... 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...

  9. A novel silica based click lysine anion exchanger for ion exchange chromatography. (United States)

    Guo, Hongyue; Chu, Changhu; Li, Yan; Yang, Bingcheng; Liang, Xinmiao


    Ion chromatography (IC) is one of the most powerful analysis technologies for the determination of charged compounds. A novel click lysine stationary phase was prepared via Cu(I) catalyzed alkyne-azide 1,3-dipolar cycloaddition (CuAAC) and applied to the analysis of inorganic ions. The chromatographic evaluation demonstrated good performance (e.g. the plate number of thiocyanate is ∼50,000 plates m(-1)) and effective separation ability for the common inorganic anions with aqueous Na(2)SO(4) eluent. The separation mechanism was observed to be mainly dominated by ion exchange interaction. The retention of these analytes is highly dependent on the pH value of eluent. Compared with the lysine stationary phase prepared via the conventional manner, the click lysine exchanger demonstrated shorter retention time and better ion separation characteristics under the same chromatographic conditions, which is a great advantage for rapid separation and analysis of inorganic ions.

  10. 1Click1View: Interactive Visualization Methodology for RNAi Cell-Based Microscopic Screening

    Directory of Open Access Journals (Sweden)

    Lukasz Zwolinski


    Full Text Available Technological advancements are constantly increasing the size and complexity of data resulting from large-scale RNA interference screens. This fact has led biologists to ask complex questions, which the existing, fully automated analyses are often not adequate to answer. We present a concept of 1Click1View (1C1V as a methodology for interactive analytic software tools. 1C1V can be applied for two-dimensional visualization of image-based screening data sets from High Content Screening (HCS. Through an easy-to-use interface, one-click, one-view concept, and workflow based architecture, visualization method facilitates the linking of image data with numeric data. Such method utilizes state-of-the-art interactive visualization tools optimized for fast visualization of large scale image data sets. We demonstrate our method on an HCS dataset consisting of multiple cell features from two screening assays.

  11. Assessing the Delivery of Molecules to the Mitochondrial Matrix Using Click Chemistry (United States)

    Hoogewijs, Kurt; James, Andrew M.; Smith, Robin A. J.


    Abstract Mitochondria are central to health and disease, hence there is considerable interest in developing mitochondria‐targeted therapies that require the delivery of peptides or nucleic acid oligomers. However, progress has been impeded by the lack of a measure of mitochondrial import of these molecules. Here, we address this need by quantitatively detecting molecules within the mitochondrial matrix. We used a mitochondria‐ targeted cyclooctyne (MitoOct) that accumulates several‐ hundredfold in the matrix, driven by the membrane potential. There, MitoOct reacts through click chemistry with an azide on the target molecule to form a diagnostic product that can be quantified by mass spectrometry. Because the membrane potential‐dependent MitoOct concentration in the matrix is essential for conjugation, we can now determine definitively whether a putative mitochondrion‐targeted molecule reaches the matrix. This “ClickIn” approach will facilitate development of mitochondria‐targeted therapies. PMID:27124570

  12. Solvent-resistant nanofiltration for product purification and catalyst recovery in click chemistry reactions. (United States)

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


    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.

  13. Light effect on Click reaction: Role of photonic quantum dot catalyst (United States)

    Nandi, Debkumar; Taher, Abu; Islam, Rafique Ul; Choudhary, Meenakshi; Siwal, Samarjeet; Mallick, Kaushik


    Due to the light excitation, the valence band electron of the copper (I) sulfide quantum dot transfer to the conduction band and act as a scavenger of the terminal proton of the alkyne in the presence of organic azide with the formation of 1,4-disubstituted 1,2,3-triazoles, where the copper(I) species of Cu2S act as a catalyst for the reaction. The above cycloaddition reaction between alkyne and azide is commonly known as the Click reaction. In this study, experiments were carried out under the exposure of ultra-violate and daylight and also dark environment. According to the original recommendation for the Click reaction, the role of the base was also considered for this experiment. We found that the effect of conduction band electron is more efficient than the recommended conventional base mediated reaction procedure.

  14. Phonemic clicks and the mapping asymmetry: How language emerged and speech developed. (United States)

    Huybregts, Riny


    Language must have existed before human populations became separated (all descendant populations have language) but language did not emerge until long after these population divergences occurred (behavioral modernity only showed then). Distinguishing capacity for language from externalized language resolves the apparent paradox. Speech emerged only after the capacity for language became fixated. This accords well with a fundamental property of human language. Rules mapping to meaning rely on structural properties only, while rules mapping to sound are (also) sensitive to linear order, reflecting properties of sensorimotor modalities. The asymmetry suggests (i) language as a system of thought takes primacy over language as communication, and (ii) evolution of the language capacity preceded emergence of speech. Click phonemes with their unique geneological, genetic and geographical distribution may be relevant here. Separation followed possession of internal language but preceded externalized language. Clicks were recruited for externalization in San populations only after deepest separation.

  15. Dietary Lipid Sources Influence Fatty Acid Composition in Tissue of Large Yellow Croaker (Larmichthys crocea) by Regulating Triacylglycerol Synthesis and Catabolism at the Transcriptional Level (United States)

    Qiu, Hong; Jin, Min; Li, Yi; Lu, You; Hou, Yingmei; Zhou, Qicun


    An 8-week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, fatty acid composition, rate-limiting enzyme activities and gene expression related to lipid metabolism in large yellow croaker (Larmichthys crocea). Five iso-nitrogenous and iso-lipidic experimental diets were formulated to contain different lipid sources, such as fish oil (FO), soybean oil (SO), linseed oil (LO), rapeseed oil (RO) and peanut oil (PO), respectively. Triplicate groups of 50 fish (initial weight 13.77±0.07g) were stocked in 15 floating net cages (1.5m×1.5m×2.0m). Fish fed the diets containing RO and LO had lower weight gain and specific growth rates than those fed the FO, SO and PO diets. Survival, feed efficiency, protein efficiency ratio, hepatosomatic index, viscerasomatic index and condition factor were not significantly affected by different dietary lipid sources. Fish fed the diet containing FO had higher lipid content in whole body compared with the other groups, whereas fish fed the SO diet had the lowest muscle lipid content. Fatty acid profiles of muscle and liver reflected the fatty acid composition of the diets. Plasma glucose, triglyceride, and the enzymatic activity of aspartate aminotransferase and alanine aminotransferase were significantly influenced by different dietary lipid sources, while total protein, cholesterol, superoxide dismutase or malondialdehyde in plasma were not affected by the different dietary lipid sources. Fish fed the LO diet had lower adipose triglyceride lipase and fatty acid synthase activities in liver than those fed the diets containing FO and RO, while the LO diet resulted in the highest hepatic carnitine palmitoultransferase-1 activity. Hepatic gene relative expression of adipose triglyceride lipase and carnitine palmitoyltransferase-1 in fish fed PO diet was significantly higher than all other groups, whereas fish fed the SO and LO diets had lower relative expression levels of lipoprotein

  16. Convenient Approach to Access Octa-Glycosylated Porphyrins via “Click Chemistry”

    Directory of Open Access Journals (Sweden)

    Misako Okada


    Full Text Available Easy, quantitative, and one-pot introduction of eight β-lactoside-modules onto a porphyrin-core was achieved through Cu+-catalyzed chemoselective coupling (click chemistry between a porphyrin carrying eight alkyne-terminals and β-lactosyl azides. The obtained porphyrin-based glycocluster shows not only good water-solubility but also strong/specific lectin-affinity.

  17. Bioorthogonal click chemistry to assay mu-opioid receptor palmitoylation using 15-hexadecynoic acid and immunoprecipitation



    We have developed a modification of bioorthogonal click chemistry to assay the palmitoylation of cellular proteins. This assay utilizes 15-hexadecynoic acid (15-HDYA) as a chemical probe in combination with protein immunoprecipitation using magnetic beads in order to detect S-palmitoylation of proteins of interest. Here we demonstrate the utility of this approach for the mu-opioid receptor (MOR), a GPCR responsible for mediating the analgesic and addictive properties of most clinically releva...

  18. Search Engines Comparison on the Basis of Session Duration and Click Hits

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar Goutam


    Full Text Available The evaluation of search engines has greatly diversified in recent years. Evaluation campaigns are required to continuously re-consider their tasks and updating evaluation function in order to satisfy the users. We presented two user action dependent approaches to rank the results, namely Session duration time and Click Hits. Furthermore, we have conducted an experiment with 25 TREC queries to do comparison of five popular search engines.

  19. Design, synthesis, and biological evaluation of novel histone deacetylase 1 inhibitors through click chemistry. (United States)

    Sun, Qiao; Yao, Yiwu; Liu, Chunping; Li, Hua; Yao, Hequan; Xue, Xiaowen; Liu, Jinsong; Tu, Zhengchao; Jiang, Sheng


    We report the design, synthesis, and biological evaluation of a new series of HDAC1 inhibitors using click chemistry. Compound 17 bearing a phenyl ring at meta-position was identified to show much better selectivity for HDAC1 over HDAC7 than SAHA. The compond 17 also showed better in vitro anticancer activities against several cancer cell lines than that of SAHA. This work could serve as a foundation for further exploration of selective HDAC inhibitors using the compound 17 molecular scaffold.

  20. Polycyclic aromatic hydrocarbons (PAHs) concentration levels, pattern, source identification and soil toxicity assessment in urban traffic soil of Dhanbad, India. (United States)

    Suman, Swapnil; Sinha, Alok; Tarafdar, Abhrajyoti


    Present study was carried out to assess and understand potential health risk and to examine the impact of vehicular traffic on the contamination status of urban traffic soils in Dhanbad City with respect to polycyclic aromatic hydrocarbons (PAHs). Eight urban traffic sites and two control/rural site surface soils were analyzed and the contents of 13 priority PAHs was determined. Total PAH concentration at traffic sites ranged from 1.019 μg g(-1) to 10.856 μg g(-1) with an average value of 3.488 μg g(-1). At control/rural site, average concentration of total PAHs was found to be 0.640 μg g(-1). PAH pattern was dominated by four- and five-ring PAHs (contributing >50% to the total PAHs) at all the eight traffic sites. On the other hand, rural soil showed a predominance of low molecular weight three-ring PAHs (contributing >30% to the total PAHs). Indeno[123-cd]pyrene/benz[ghi]perylene (IP/BgP) ratio indicated that PAH load at the traffic sites is predominated by the gasoline-driven vehicles. The ratio of Ant/(Ant+Phe) varied from 0.03 to 0.44, averaging 0.10; Fla/(Fla+Pyr) from 0.39 to 0.954, averaging 0.52; BaA/(BaA+Chry) from 0.156 to 0.60, averaging 0.44; and IP/(IP+BgP) from 0.176 to 0.811, averaging 0.286. The results indicated that vehicular emission was the major source for PAHs contamination with moderate effect of coal combustion and biomass combustion. Carcinogenic potency of PAH load in traffic soil was nearly 6.15 times higher as compared to the control/rural soil.

  1. Fossil DNA Stratigraphy revealed Multiple Sources of Alkenones in the Holocene Black Sea at the Strain Level: Implications for UK37 Paleothermometry (United States)

    Coolen, M. J.; Saenz, J. P.; Trowbridge, N.; Eglinton, T.


    The fossil distribution of long-chain alkenones is now a widely accepted tool to reconstruct past sea surface temperatures (SST) (i.e. UK37-index). In most studies, the UK37 index is calibrated for the main source of alkenones, the coccolithophorid haptophyte Emiliania huxleyi. Besides temperature, additional factors such as salinity, growth conditions, or different or multiple biological sources seem to influence the level of unsaturation of alkenones and the reliability of the UK37-inferred SST. The Black Sea is an interesting setting to study such factors since unreliable SST were reconstructed from the Holocene sapropel with high concentrations of an unusual "Black Sea" alkenone (C36:2 ethyl ketone) whereas calcium-bearing microfossils (coccoliths) of haptophytes are lacking. To identify Holocene sources for alkenones in the Black Sea at the unprecedented strain-level and to refine paleoenvironmental conditions, we searched for multiple fossil genetic signatures of haptophytes. This revealed that the slow increase in salinity as a result of post-glacial introduction of Mediterranean waters in the paleo lacustrine Black Sea, caused a succession between alkenone-biosynthesizing haptophytes from Isochrysis spp. (which do not produce coccoliths), to a mixture of Isochrysis and E huxleyi strains, then only E. huxleyi strains, and when the salinity reached a threshold of 18 per mille at 3000 years BP, the fossilized calcium-bearing E. huxleyi strain was introduced. At least 11 E. huxleyi strains were identified and the first non-fossilizing strains already colonized the Black Sea 4000 years before the fossilized calcium-bearing strain appeared. Most E. huxleyi strains were likely sources of C36:2 eK but the presence of one fossil "phylotype" coincided with the highest levels of this unusual alkenone ( more than 80 percent of the total alkenone content) and unreliable past SST (varying between 5 and 30 degrees C; 7500-5500 years BP). C36:2 eK was not biosynthesized by

  2. Sediment baseline study of levels and sources of polycyclic aromatic hydrocarbons and heavy metals in Lake Nicaragua

    DEFF Research Database (Denmark)

    Scheibye, Katrine; Weisser, Johan; Borggaard, Ole K.;


    Selected metals and polycyclic aromatic hydrocarbons (PAHs) were analyzed in sediment samples from 24 sites in Lake Nicaragua sampled May 2010 to provide a baseline of pollution levels. Cu exceeded the Consensus-Based Sediment Quality Guideline (CBSQG) Threshold Effect Concentrations (TECs) at 21...... showed that the CBSQG TECs were exceeded by naphthalene at five sites. The sum concentrations of the 16 US EPA priority PAHs (∑PAH16) ranged from 0.01mgkg(-1)dw to 0.64mgkg(-1)dw. The highest ∑PAH16 concentration was found upstream in River Mayales and the PAH composition revealed a heavy PAH fraction (e....... This study concluded that areas of Lake Nicaragua represent an important pollution baseline for future studies in this lake and other tropical lakes....

  3. Label-free electrochemical monitoring of protein addressing through electroactivated "click" chemistry on gold electrodes. (United States)

    Meini, Nadir; Ripert, Micaël; Chaix, Carole; Farre, Carole; De Crozals, Gabriel; Kherrat, Rochdi; Jaffrezic-Renault, Nicole


    In this work, using electrochemical impedance spectroscopy (EIS), we have, for the first time, label-free monitored protein immobilization on a gold surface through a strategy of electroaddressing, compatible with the production of microarrays for multi-detection. This functionalization is achieved via the alkyne/azide cycloaddition, better known as the "click" reaction. The electroaddressing was applied to a polythiol hexynyl derivative previously grafted onto the gold surface. This compound consists of two dithiol phosphate groups and a hexynyl function and was synthesized through a supported synthesis approach, from a dithiol reagent, phosphoramidite (DTPA), and a hexynyl phosphoramidite. Next, an azide-PEG3-biotin derivative was grafted onto the modified gold surface by electro-chronocoulometry. The "click" reaction was controlled by electrochemical impedance spectroscopy, showing the change in impedance only when the electroaddressing was performed at -300 mV. No effect on the EIS signal was observed when a positive potential was applied, confirming the specificity of the electroactivation. Biotin-modified electrodes were used to fix streptavidin and the immobilization was monitored using EIS. Fluorescent streptavidin-functionalized silica nanoparticles were also specifically grafted onto the biotinylated gold surface in order to confirm the "click" reaction using fluorescence microscopy. The obtained streptavidin platform was used to detect the surface coverage by biotinylated human serum albumin (HSA). The lowest detectable concentration is 10 pg/mL, and surface saturation is obtained with concentrations higher than 100 ng/mL.

  4. Facile and Efficient Synthesis of Carbosiloxane Dendrimers via Orthogonal Click Chemistry Between Thiol and Ene. (United States)

    Zhang, Zhida; Feng, Shengyu; Zhang, Jie


    A combination of a thiol-Michael addition reaction and a free radical mediated thiol-ene reaction is employed as a facile and efficient approach to carbosiloxane dendrimer synthesis. For the first time, carbosiloxane dendrimers are constructed rapidly by an orthogonal click strategy without protection/deprotection procedures. The chemoselectivity of these two thiol-ene click reactions leads to a design of a new monomer containing both electron-deficient carbon-carbon double bonds and unconjugated carbon-carbon double bonds. Siloxane bonds are introduced as the linker between these two kinds of carbon-carbon double bonds. Starting from a bifunctional thiol core, the dendrimers are constructed by iterative thiol-ene click reactions under different but both mild reaction conditions. After simple purification steps the fifth dendrimer with 54 peripheral functional groups is obtained with an excellent overall yield in a single day. Furthermore, a strong blue glow is observed when the dendrimer is excited by a UV lamp.

  5. 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:


    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.

  6. Clicks, whistles and pulses: Passive and active signal use in dolphin communication (United States)

    Herzing, Denise L.


    The search for signals out of noise is a problem not only with radio signals from the sky but in the study of animal communication. Dolphins use multiple modalities to communicate including body postures, touch, vision, and most elaborately sound. Like SETI radio signal searches, dolphin sound analysis includes the detection, recognition, analysis, and interpretation of signals. Dolphins use both passive listening and active production to communicate. Dolphins use three main types of acoustic signals: frequency modulated whistles (narrowband with harmonics), echolocation (broadband clicks) and burst pulsed sounds (packets of closely spaced broadband clicks). Dolphin sound analysis has focused on frequency-modulated whistles, yet the most commonly used signals are burst-pulsed sounds which, due to their graded and overlapping nature and bimodal inter-click interval (ICI) rates are hard to categorize. We will look at: 1) the mechanism of sound production and categories of sound types, 2) sound analysis techniques and information content, and 3) examples of lessons learned in the study of dolphin acoustics. The goal of this paper is to provide perspective on how animal communication studies might provide insight to both passive and active SETI in the larger context of searching for life signatures.

  7. Orthogonal spin labeling using click chemistry for in vitro and in vivo applications (United States)

    Kucher, Svetlana; Korneev, Sergei; Tyagi, Swati; Apfelbaum, Ronja; Grohmann, Dina; Lemke, Edward A.; Klare, Johann P.; Steinhoff, Heinz-Jürgen; Klose, Daniel


    Site-directed spin labeling for EPR- and NMR spectroscopy has mainly been achieved exploiting the specific reactivity of cysteines. For proteins with native cysteines or for in vivo applications, an alternative coupling strategy is required. In these cases click chemistry offers major benefits by providing a fast and highly selective, biocompatible reaction between azide and alkyne groups. Here, we establish click chemistry as a tool to target unnatural amino acids in vitro and in vivo using azide- and alkyne-functionalized spin labels. The approach is compatible with a variety of labels including reduction-sensitive nitroxides. Comparing spin labeling efficiencies from the copper-free with the strongly reducing copper(I)-catalyzed azide-alkyne click reaction, we find that the faster kinetics for the catalyzed reaction outrun reduction of the labile nitroxide spin labels and allow quantitative labeling yields within short reaction times. Inter-spin distance measurements demonstrate that the novel side chain is suitable for paramagnetic NMR- or EPR-based conformational studies of macromolecular complexes.

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

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


    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 (0.3 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.

  9. Layer-by-layer click deposition of functional polymer coatings for combating marine biofouling. (United States)

    Yang, Wen Jing; Pranantyo, Dicky; Neoh, Koon-Gee; Kang, En-Tang; Teo, Serena Lay-Ming; Rittschof, Daniel


    "Click" chemistry-enabled layer-by-layer (LBL) deposition of multilayer functional polymer coatings provides an alternative approach to combating biofouling. Fouling-resistant azido-functionalized poly(ethylene glycol) methyl ether methacrylate-based polymer chains (azido-poly(PEGMA)) and antimicrobial alkynyl-functionalized 2-(methacryloyloxy)ethyl trimethyl ammonium chloride-based polymer chains (alkynyl-poly(META)) were click-assembled layer-by-layer via alkyne-azide 1,3-dipolar cycloaddition. The polymer multilayer coatings are resistant to bacterial adhesion and are bactericidal to marine Gram-negative Pseudomonas sp. NCIMB 2021 bacteria. Settlement of barnacle ( Amphibalanus (= Balanus ) amphitrite ) cyprids is greatly reduced on the multilayer polymer-functionalized substrates. As the number of the polymer layers increases, efficacy against bacterial fouling and settlement of barnacle cyprids increases. The LBL-functionalized surfaces exhibit low toxicity toward the barnacle cyprids and are stable upon prolonged exposure to seawater. LBL click deposition is thus an effective and potentially environmentally benign way to prepare antifouling coatings.

  10. Modulation of Quantum Dot Energy Levels by Surface Acoustic Waves for use as a Triggered Photon Source (United States)

    Hubert, Colin

    The foundation for a triggered photon source was realized by convolving the energy bandgap of a quantum dot with a surface acoustic wave. The devices consisted of an InP substrate on which InAs/InP quantum dots were grown. It was then coated with a layer of piezoelectric ZnO by radio-frequency magnetic sputtering. Modulation of the device was enabled through aluminum interdigitated transducers that were deposited on the sample, which excited surface acoustic waves. The expected resonance of the interdigitated transducers was around 200 MHz. However, resonances at 200 MHz and 300 MHz were recorded, due a Sezawa mode excitation. The preferential excitation of modes was likely due to variations in the ZnO film thickness. The target quantum dot emission was around 1550 nm, matching with the C-band used in fibre optic communication channels. The largest wavelength measured for the ground state energy emissions from these dots was 1580 nm, though typical lowest energy emission peaks were in the range of 1300-1400 nm. Unidirectional Stark shifts in the photoluminescence emission of the quantum dots were observed as surface acoustic waves were applied. This quantum confined Stark effect is thought to be due the polarization of the InP/InAs due to the electric field in the ZnO layer, providing a second order effect. The electrical field from the ZnO layer potentially contributes a linear effect. The modulation of the quantum dot energy is due to the strain field but due to the electrical coupling form the ZnO layer, exact determination of the strain field's contribution is not possible. The emission modulation effect is quadratically dependent on both applied SAW power and inital emission energy. Convolution of the quantum dot emission with the surface acoustic wave-induced bandgap modulation was also observed, resulting in a split emission peak. A splitting of 4.97 meV was observed using a linear surface acoustic wave power density of at least 1.69 W/m and a laser

  11. Assessing the potential hydrological impact of the Gibe III Dam on Lake Turkana water level using multi-source satellite data

    Directory of Open Access Journals (Sweden)

    N. M. Velpuri


    Full Text Available Lake Turkana, the largest desert lake in the world, is fed by ungauged or poorly gauged river systems. To meet the demand of electricity in the East African region, Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies more than 80% of the inflows to Lake Turkana. On completion, the Gibe III dam will be the tallest dam in Africa with a height of 241 m. However, the nature of interactions and potential impacts of regulated inflows to Lake Turkana are not well understood due to its remote location and unavailability of reliable in situ datasets. In this study, we used 12 yr (1998–2009 of existing multi-source satellite and model-assimilated global weather data. We used a calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model evaluates the impact of the Gibe III dam using three different approaches – a historical approach, a rainfall based approach, and a statistical approach to generate rainfall-runoff scenarios. All the approaches provided comparable and consistent results. Model results indicated that the hydrological impact of the Gibe III dam on Lake Turkana would vary with the magnitude and distribution of rainfall post-dam commencement. On average, the reservoir would take up to 8–10 months, after commencement, to reach a minimum operation level of 201 m depth of water. During the dam filling period, the lake level would drop up to 1–2 m (95% confidence compared to the lake level modeled without the dam. The lake level variability caused by regulated inflows after the dam commissioning were found to be within the natural variability of the lake of 4.8 m. Moreover, modeling results indicated that the hydrological impact of the Gibe III dam would depend on the initial lake level at the time of

  12. Assessing the potential hydrological impact of the Gibe III Dam on Lake Turkana water level using multi-source satellite data

    Directory of Open Access Journals (Sweden)

    N. M. Velpuri


    Full Text Available Lake Turkana, the largest desert lake in the world, is fed by ungauged or poorly gauged river systems. To meet the demand of electricity in the East African region, Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies more than 80% of the inflows to Lake Turkana. On completion, the Gibe III dam will be the tallest dam in Africa with a height of 241 m. However, the nature of interactions and potential impacts of regulated inflows to Lake Turkana are not well understood due to its remote location and unavailability of reliable in-situ datasets. In this study, we used 12 years (1998–2009 of existing multi-source satellite and model-assimilated global weather data. We use calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model evaluates the impact of Gibe III dam using three different approaches such as (a historical approach, a knowledge-based approach, and a nonparametric bootstrap resampling approach to generate rainfall-runoff scenarios. All the approaches provided comparable and consistent results. Model results indicated that the hydrological impact of the dam on Lake Turkana would vary with the magnitude and distribution of rainfall post-dam commencement. On average, the reservoir would take up to 8–10 months, after commencement, to reach a minimum operation level of 201 m depth of water. During the dam filling period, the lake level would drop up to 2 m (95% confidence compared to the lake level modelled without the dam. The lake level variability caused by regulated inflows after the dam commissioning were found to be within the natural variability of the lake of 4.8 m. Moreover, modelling results indicated that the hydrological impact of the Gibe III dam would depend on the initial lake level

  13. Assessing the Potential Hydrological Impact of the Gibe III Dam on Lake Turkana Water Level Using Multi-Source Satellite Data (United States)

    ,; Senai, G.B.


    Lake Turkana, the largest desert lake in the world, is fed by ungauged or poorly gauged river systems. To meet the demand of electricity in the East African region, Ethiopia is currently building the Gibe III hydroelectric dam on the Omo River, which supplies more than 80% of the inflows to Lake Turkana. On completion, the Gibe III dam will be the tallest dam in Africa with a height of 241 m. However, the nature of interactions and potential impacts of regulated inflows to Lake Turkana are not well understood due to its remote location and unavailability of reliable in-situ datasets. In this study, we used 12 years (1998–2009) of existing multi-source satellite and model-assimilated global weather data. We use calibrated multi-source satellite data-driven water balance model for Lake Turkana that takes into account model routed runoff, lake/reservoir evapotranspiration, direct rain on lakes/reservoirs and releases from the dam to compute lake water levels. The model evaluates the impact of Gibe III dam using three different approaches such as (a historical approach, a knowledge-based approach, and a nonparametric bootstrap resampling approach) to generate rainfall-runoff scenarios. All the approaches provided comparable and consistent results. Model results indicated that the hydrological impact of the dam on Lake Turkana would vary with the magnitude and distribution of rainfall post-dam commencement. On average, the reservoir would take up to 8–10 months, after commencement, to reach a minimum operation level of 201 m depth of water. During the dam filling period, the lake level would drop up to 2 m (95% confidence) compared to the lake level modelled without the dam. The lake level variability caused by regulated inflows after the dam commissioning were found to be within the natural variability of the lake of 4.8 m. Moreover, modelling results indicated that the hydrological impact of the Gibe III dam would depend on the initial lake level at the time of

  14. Energy sources and levels influenced on performance parameters, thyroid hormones, and HSP70 gene expression of broiler chickens under heat stress. (United States)

    Raghebian, Majid; Sadeghi, Ali Asghar; Aminafshar, Mehdi


    The present study was conducted to evaluate the effects of energy sources and levels on body and organs weights, thyroid hormones, and heat shock protein (HSP70) gene expression in broilers under heat stress. In a completely randomized design, 600 1-day-old Cobb chickens were assigned to five dietary treatments and four replicates. The chickens were fed diet based on corn as main energy source and energy level based on Cobb standard considered as control (C), corn-based diet with 3 % lesser energy than the control (T1), corn-based diet with 6 % lesser energy than the control (T2), corn and soybean oil-based diet according to Cobb standard (T3), and corn and soybean oil-based diet with 3 % upper energy than the control (T4). Temperature was increased to 34 °C for 8 h daily from days 12 to 41 of age to induce heat stress. The chickens in T1 and T2 had lower thyroid hormones and corticosterone levels than those in C, T3, and T4. The highest liver weight was for C and the lowest one was for T4. The highest gene expression was found in chickens fed T4 diet, and the lowest gene expression was for those in T2 group. The highest feed intake and worse feed conversion ratio was related to chickens in T2. The chickens in T3 and T4 had higher feed intake and weight gain than those in C. The results showed that the higher energy level supplied from soybean oil could enhance gene expression of HSP70 and decline the level of corticosterone and thyroid hormones and consequently improved performance.

  15. Levels and sources of brominated flame retardants in human hair from urban, e-waste, and rural areas in South China

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Jing [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275 (China); Luo Xiaojun, E-mail: [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Yuan Jiangang [State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275 (China); Wang Jing [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Graduate University of Chinese Academy of Science, Beijing 100049 (China); Wang Yutao [State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275 (China); Chen Shenjun; Mai Bixian [State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640 (China); Yang Zhongyi, E-mail: [State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-Sen University, Guangzhou 510275 (China)


    Human hair and indoor dust from urban, e-waste, and rural areas in south China were collected and analyzed for brominated flame retardants (BFRs). BFRs concentrations in hair from occupational e-waste recycling workers were higher than those from non-occupational exposed residents in other sampling areas. Polybrominated diphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) are two major BFRs in hair samples. The PBDE congener profiles in hair from the e-waste area are different from those from urban and rural areas with relatively higher contribution of lower brominated congeners. DBDPE, instead of BDE209, has become the major BFR in non-e-waste recycling areas. Significant correlations were found between hair level and dust level for DBDPE and BTBPE but not for PBDEs. The different PBDE congener profiles between dust and hair may suggest that exogenous exposure to the PBDE adsorbed on dust is not a major source of hair PBDEs. - Highlights: > In this study we examine BFRs in human hair and indoor dust from the South China. > We find that the composition of BFR in the e-waste area is different from other areas. > DBDPE, instead of BDE209, has become the major BFR in non-e-waste recycling areas. > The PBDE congener pattern in hair is different from those in indoor dust. > In this study we conclude that exogenous exposure to the PBDE is not a major source of hair PBDEs. - BFR levels in hair from different areas in South China were determined and endogenous pathway was found to be the major source of hair BFRs.

  16. 巯基-烯点击化学%Thiol-Ene Click Chemistry

    Institute of Scientific and Technical Information of China (English)

    徐源鸿; 熊兴泉; 蔡雷; 唐忠科; 叶章基


    Click chemistry", introduced by Sharpless in 2001, becomes a new synthetic method used in areas such as drugs, polymers and materials rapidly because of its high efficiency, high selectivity and reliable characteristics. With the further research on click chemistry, the types of it are increasing continuously and the scope of application is also expanding. Radical-mediated or nucleophile-initiated thiol-ene reaction is a novel kind of click reactions, which shows the characteristics of click chemistry. Starting from the concept, characteristic and types of click chemistry, the mechanism and the wide applications of thiol-ene reaction in preparation of functional polymers and topologic macromolecules, polymeric materials surface modification and biomaterials are emphasized. Furthermore, the latest research based on thiol-ene chemistry is summarized. The prospects of thiol-ene reaction are also discussed.%点击化学自2001年由Sharpless提出后,由于其高效、可靠、高选择性的特点迅速成为药物和高分子材料合成的新方法。随着对点击化学研究的深入,其反应类型在不断增多,应用范围也在不断扩大。自由基或亲核试剂引发的巯基.烯反应作为其中一种新型的点击反应具有点击化学的所有特性。本文从点击化学的概念、特征和类型出发,重点介绍了巯基-烯反应的机理和在合成功能聚合物、制备拓扑结构高分子、表面修饰以及生物药物等方面的应用,并对巯基.烯反应的最新研究成果进行综述,最后展望了巯基-烯的点击化学的发展前景。

  17. Investigation of levels in ambient air near sources of Polychlorinated Biphenyls (PCBs) in Kanpur, India, and risk assessment due to inhalation. (United States)

    Goel, Anubha; Upadhyay, Kritika; Chakraborty, Mrinmoy


    Polychlorinated biphenyls (PCBs) are a class of organic compounds listed as persistent organic pollutant and have been banned for use under Stockholm Convention (1972). They were used primarily in transformers and capacitors, paint, flame retardants, plasticizers, and lubricants. PCBs can be emitted through the primary and secondary sources into the atmosphere, undergo long-range atmospheric transport, and hence have been detected worldwide. Reported levels in ambient air are generally higher in urban areas. Active sampling of ambient air was conducted in Kanpur, a densely populated and industrialized city in the Indo-Gangetic Plain, for detection of 32 priority PCBs, with the aim to determine the concentration in gas/particle phase and assess exposure risk. More than 50 % of PCBs were detected in air. Occurrence in particles was dominated by heavier congeners, and levels in gas phase were below detection. Levels determined in this study are lower than the levels in Coastal areas of India but are at par with other Asian countries where majority of sites chosen for sampling were urban industrial areas. Human health risk estimates through air inhalation pathway were made in terms of lifetime average daily dose (LADD) and incremental lifetime cancer risks (ILCR). The study found lower concentrations of PCBs than guideline values and low health risk estimates through inhalation within acceptable levels, indicating a minimum risk to the adults due to exposure to PCBs present in ambient air in Kanpur.

  18. Levels and potential sources of decabromodiphenyl ethane (DBDPE) and decabromodiphenyl ether (DecaBDE) in lake and marine sediments in Sweden. (United States)

    Ricklund, Niklas; Kierkegaard, Amelie; McLachlan, Michael S


    Decabromodiphenyl ethane (DBDPE) is a brominated flame retardant (BFR) used as a replacement for the structurally similar decabromodiphenyl ether (decaBDE), which is a regulated environmental contaminant of concern. DBDPE has been found in indoor dust, sewage sludge, sediment, and biota, but little is known about its occurrence and distribution in the environment In this paper, sediment was analyzed from 11 isolated Swedish lakes and along a transect running from central Stockholm through the Stockholm archipelago to the Baltic Sea. DBDPE was present in all samples. In lake sediment, the levels ranged from 0.23 to 11 ng/g d.wt. and were very similar to the levels of decaBDE (0.48-11 ng/g d.wt.). Since the lakes have no known point sources of BFRs, their presence in the sediments provides evidence for long-range atmospheric transport and deposition. In the marine sediment, the DBDPE and decaBDE levels decreased by a factor of 20-50 over 40 km from the inner harbor to the outer archipelago. There the DBDPE and decaBDE levels were similar to the levels in nearby isolated lakes. The results indicate that contamination of the Swedish environment with DBDPE has already approached that of decaBDE, and that this contamination is primarily occurring via the atmosphere.

  19. Modification of chemical and conformational properties of natural organic matter by click chemistry as revealed by ESI-Orbitrap mass spectrometry. (United States)

    Nebbioso, Antonio; Piccolo, Alessandro


    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.

  20. Levels and sources of brominated flame retardants in human hair from urban, e-waste, and rural areas in South China. (United States)

    Zheng, Jing; Luo, Xiao-Jun; Yuan, Jian-Gang; Wang, Jing; Wang, Yu-Tao; Chen, Shen-Jun; Mai, Bi-Xian; Yang, Zhong-Yi


    Human hair and indoor dust from urban, e-waste, and rural areas in south China were collected and analyzed for brominated flame retardants (BFRs). BFRs concentrations in hair from occupational e-waste recycling workers were higher than those from non-occupational exposed residents in other sampling areas. Polybrominated diphenyl ethers (PBDEs) and decabromodiphenyl ethane (DBDPE) are two major BFRs in hair samples. The PBDE congener profiles in hair from the e-waste area are different from those from urban and rural areas with relatively higher contribution of lower brominated congeners. DBDPE, instead of BDE209, has become the major BFR in non-e-waste recycling areas. Significant correlations were found between hair level and dust level for DBDPE and BTBPE but not for PBDEs. The different PBDE congener profiles between dust and hair may suggest that exogenous exposure to the PBDE adsorbed on dust is not a major source of hair PBDEs.

  1. Interactive Sea Level Rise App & Online Viewer Offers Deep Dive Into Climate (United States)

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


    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

  2. Modeling of Morelia Fault Earthquake (Mw=5.4) source fault parameters using the coseismic ground deformation and groundwater level changes data (United States)

    Sarychikhina, O.; Glowacka, E.; Mellors, R. J.; Vázquez, R.


    On 24 May 2006 at 04:20 (UTC) a moderate-size (Mw=5.4) earthquake struck the Mexicali Valley, Baja California, México, roughly 30 km to the southeast of the city of Mexicali, in the vicinity of the Cerro Prieto Geothermal Field (CPGF). The earthquake occurred on the Morelia fault, one of the east-dipping normal faults in the Mexicali Valley. Locally, this earthquake was strongly felt and caused minor damage. The event created 5 km of surface rupture and down-dip displacements of up to 25-30 cm were measured at some places along this surface rupture. Associated deformation was measured by vertical crackmeter, leveling profile, and Differential Synthetic Aperture Radar Interferometry (D-InSAR). A coseismic step-like groundwater level change was detected at 7 wells. The Mw=5.4 Morelia Fault earthquake had significant scientific interest, first, because of surprisingly strong effects for an earthquake of such size; second, the variability of coseismic effects data from different ground-based and space-based techniques which allows to the better constrain of the source fault parameters. Source parameters for the earthquake were estimated using forward modeling of both surface deformation data and static volume strain change (inferred from coseismic changes in groundwater level). All ground deformation data was corrected by anthropogenic component caused by the geothermal fluid exploitation in the CPGF. Modeling was based on finite rectangular fault embedded in an elastic media. The preferred fault model has a strike, rake, and dip of (48°, -89°, 45°) and has a length of 5.2 km, width of 6.7 km, and 34 cm of uniform slip. The geodetic moment, based on the modeled fault parameters, is 1.18E+17 Nm. The model matches the observed surface deformation, expected groundwater level changes, and teleseismic moment reasonably well and explains in part why the earthquake was so strongly felt in the area.

  3. Tetrathiafulvalene mono- and bis-1,2,3-triazole precursors by click chemistry: structural diversity and reactivity. (United States)

    Biet, Thomas; Avarvari, Narcis


    The donor ortho-dimethyl-TTF-(N-n-Bu-1,2,3-triazole) 1,5-isomer has been synthesized by click chemistry following a ruthenium-catalyzed azide-alkyne cycloaddition procedure. The single crystal X-ray analysis showed a planar conformation between the TTF and triazole units and a set of intermolecular interactions at the supramolecular level in the solid state. The same procedure allowed the preparation of the corresponding ortho-dimethyl-TTF-bis(triazole) which was also structurally characterized. Because of the steric hindrance, the triazole units are no longer planar with the TTF backbone. The reactivity of the triazole ring has been investigated in protonation and alkylation reactions, monitored by UV-visible spectroscopy, which clearly showed the red shift of the intramolecular charge transfer band. A TTF-methyl-triazolium salt has been isolated and analyzed by single crystal X-ray analysis. All of the TTF-triazoles and triazolium salts are valuable precursors for radical cation salts due to their oxidation potentials and variety of possible intermolecular interactions.

  4. The site of net absorption of Ca from the intestinal tract of growing pigs and effect of phytic acid, Ca level and Ca source on Ca digestibility. (United States)

    González-Vega, J Caroline; Walk, Carrie L; Liu, Yanhong; Stein, Hans H


    An experiment was conducted to test the hypothesis that the standardised digestibility of Ca in calcium carbonate and Lithothamnium calcareum Ca is not different regardless of the level of dietary Ca, and that phytic acid affects the digestibility of Ca in these two ingredients to the same degree. The objectives were to determine where in the intestinal tract Ca absorption takes place and if there are measurable quantities of basal endogenous Ca fluxes in the stomach, small intestine or large intestine. Diets contained calcium carbonate or L. calcareum Ca as the sole source of Ca, 0% or 1% phytic acid and 0.4% or 0.8% Ca. A Ca-free diet was also formulated and used to measure endogenous fluxes and losses of Ca. Nine growing pigs (initial body weight 23.8 ± 1.3 kg) were cannulated in the duodenum and in the distal ileum, and faecal, ileal and duodenal samples were collected. Duodenal endogenous fluxes of Ca were greater (p phytic acid, but decreased (p phytic acid, but may be affected by dietary Ca level depending on the Ca source. Calcium from calcium carbonate is mostly absorbed before the duodenum, but Ca from L. calcareum Ca is mostly absorbed in the jejunum and ileum.

  5. High-density functionalization and cross-linking of DNA: "click" and "bis-click" cycloadditions performed on alkynylated oligonucleotides with fluorogenic anthracene azides. (United States)

    Pujari, Suresh S; Ingale, Sachin A; Seela, Frank


    High density functionalization of DNA with ethynyl and octadiynyl side chains followed by CuAAC "click labeling" with 9-azidomethylanthracene was performed. Alkynyl DNA was also cross-linked with fluorogenic 9,10-bis-azidomethylanthracene employing the "bis-click" reaction. By this means the fluorescence of the anthracene moiety was imparted to the virtually nonfluorescent DNA. Phosphoramidites of 8-aza-7-deaza-2'-deoxyadenosine with short and long linker arms in a steric nondemanding 7-position were utilized in solid phase oligodeoxynucleotide synthesis. High density alkynylated DNA-without anthracene residues-was found to be of comparable stability with both long and short linker arms. High density anthracene functionalized DNA became less stable with the short linker compared to that with the long linker connectivity. Interstrand cross-linked homodimers constructed from alkynylated oligonucleotides with fluorogenic 9,10-bis-azidomethylanthracene were hybridized with complementary strands to form double helices. They are more stable when the linker was located at a terminus than in a central position. Short linker anthracene adducts were destabilizing compared to long linker adducts. The fluorogenic anthracene residues not only have a significant effect on the duplex stability, but also impart fluorescence to the species. Fluorescence of cross-linked double helices with long linker connectivity was quenched when the cross-link was in a terminal position and was dequenched when the linker was connecting the two double helices at the center of the molecule. The fluorescence of the anthracene cross-linked double helices was strongly increased (dequenched) when the correct base pair was formed, while no change occurred upon mismatch formation.

  6. Observation of the controlled assembly of preclick components in the in situ click chemistry generation of a chitinase inhibitor. (United States)

    Hirose, Tomoyasu; Maita, Nobuo; Gouda, Hiroaki; Koseki, Jun; Yamamoto, Tsuyoshi; Sugawara, Akihiro; Nakano, Hirofumi; Hirono, Shuichi; Shiomi, Kazuro; Watanabe, Takeshi; Taniguchi, Hisaaki; Sharpless, K Barry; Omura, Satoshi; Sunazuka, Toshiaki


    The Huisgen cycloaddition of azides and alkynes, accelerated by target biomolecules, termed "in situ click chemistry," has been successfully exploited to discover highly potent enzyme inhibitors. We have previously reported a specific Serratia marcescens chitinase B (SmChiB)-templated syn-triazole inhibitor generated in situ from an azide-bearing inhibitor and an alkyne fragment. Several in situ click chemistry studies have been reported. Although some mechanistic evidence has been obtained, such as X-ray analysis of [protein]-["click ligand"] complexes, indicating that proteins act as both mold and template between unique pairs of azide and alkyne fragments, to date, observations have been based solely on "postclick" structural information. Here, we describe crystal structures of SmChiB complexed with an azide ligand and an O-allyl oxime fragment as a mimic of a click partner, revealing a mechanism for accelerating syn-triazole formation, which allows generation of its own distinct inhibitor. We have also performed density functional theory calculations based on the X-ray structure to explore the acceleration of the Huisgen cycloaddition by SmChiB. The density functional theory calculations reasonably support that SmChiB plays a role by the cage effect during the pretranslation and posttranslation states of selective syn-triazole click formation.

  7. The effects of preceding lead-alone and lag-alone click trains on the buildup of echo suppression. (United States)

    Bishop, Christopher W; Yadav, Deepak; London, Sam; Miller, Lee M


    Spatial perception in echoic environments is influenced by recent acoustic history. For instance, echo suppression becomes more effective or "builds up" with repeated exposure to echoes having a consistent acoustic relationship to a temporally leading sound. Four experiments were conducted to investigate how buildup is affected by prior exposure to unpaired lead-alone or lag-alone click trains. Unpaired trains preceded lead-lag click trains designed to evoke and assay buildup. Listeners reported how many sounds they heard from the echo hemifield during the lead-lag trains. Stimuli were presented in free field (experiments 1 and 4) or dichotically through earphones (experiments 2 and 3). In experiment 1, listeners reported more echoes following a lead-alone train compared to a period of silence. In contrast, listeners reported fewer echoes following a lag-alone train; similar results were observed with earphones. Interestingly, the effects of lag-alone click trains on buildup were qualitatively different when compared to a no-conditioner trial type in experiment 4. Finally, experiment 3 demonstrated that the effects of preceding click trains on buildup cannot be explained by a change in counting strategy or perceived click salience. Together, these findings demonstrate that echo suppression is affected by prior exposure to unpaired stimuli.

  8. Influence of dietary calcium level, calcium source, and phytase on bird performance and mineral digestibility during a natural necrotic enteritis episode. (United States)

    Paiva, D M; Walk, C L; McElroy, A P


    The objective of this study was to determine the influence of Ca source [highly soluble calcified seaweed (HSC) or limestone], phytase supplementation, and dietary levels of Ca on bird performance and mineral digestibility (Ca and P) during a necrotic enteritis (NE) episode. Cobb 500 male broilers were weighed and randomized into 8 treatment groups (9 pens/treatment; 30 birds/pen) at day of hatch. The 21-d trial was designed as a 2 × 2 × 2 factorial, which included 2 dietary levels of Ca (0.6 and 0.9%), 2 Ca sources (limestone or HSC), and 2 levels of an Escherichia coli phytase (0 or 1,000 FTU/kg). One unit of phytase (FTU) is defined as the quantity of enzyme that releases 1 μmol of inorganic phosphorus/min from 0.00015 mol/L of sodium phytate at pH 5.5 at 37° C. Birds were placed on used litter from a previous flock that exhibited clinical signs of NE. Birds and feed were weighed on d 7, 14, and 21, and BW gain, feed intake, and feed conversion were calculated for each of these periods and cumulatively. Mortality was recorded daily and pH of the gizzard and duodenum were measured on d 7, 14, and 21. Ileal digesta (8 birds/pen) was collected on d 7, 14, and 21. Significance is reported at P phytase were heavier than the other treatments regardless of Ca source. Broilers fed diets formulated with HSC had significantly higher feed conversion then broilers fed diets formulated with limestone. The gizzard of broilers fed 0.9% Ca in the diet was significantly less acidic than the gizzard of broilers fed 0.6% Ca in the diet. Broilers fed 0.6% Ca in diets supplemented with phytase showed significant improvements in P and Ca digestibility. In conclusion, higher dietary Ca (0.9% vs. 0.6%) had a negative effect on mortality associated with NE and on bird performance.

  9. Influence of source and level of glycerin in the diet on growth performance, liver characteristics, and nutrient digestibility in broilers from hatching to 21 days of age. (United States)

    Mandalawi, H A; Kimiaeitalab, M V; Obregon, V; Menoyo, D; Mateos, G G


    The influence of source and level of inclusion of raw glycerin (GLYC) in the diet on growth performance, digestive traits, total tract apparent retention (TTAR), and apparent ileal digestibility of nutrients was studied in broilers from 1 to 21 d of age. There was a control diet based on corn and soybean meal and 8 additional diets that formed a 2 × 4 factorial with 2 sources of GLYC and 4 levels of inclusion (2.5, 5.0, 7.5, and 10%). The GLYC used were obtained from the same original batch of soy oil that was dried under different processing conditions and contained 87.5 or 81.6% glycerol, respectively. Type of processing of the GLYC did not affect any of the variables studied except DM and organic matter retention (P < 0.05) that was higher for the 87.5% glycerol diet. From d 1 to 21, feed conversion ratio (FCR) improved linearly (L, P ≤ 0.01) as the GLYC content of the diet increased, but ADG was not affected. On d 21, the relative weight (% BW) of the liver and the digestive tract increased (L, P < 0.01) as the level of GLYC in the diet increased, but lipid concentration in the liver was not affected. The TTAR of DM and organic matter increased quadratically (Q, P < 0.05) and the AME(n) content of the diet increased linearly (L, P < 0.01) with increases in dietary GLYC. Also, the apparent ileal digestibility of DM (L, P < 0.05; Q, P = 0.07) and gross energy (L, P < 0.01) increased as the GLYC content of the diet increased. It is concluded that raw GLYC from the biodiesel industry can be used efficiently, up to 10% of the diet, as a source of energy for broilers from 1 to 21 d of age and that the energy content of well-processed raw GLYC depends primarily on its glycerol content.

  10. Evaluating and Optimizing Online Advertising: Forget the Click, but There Are Good Proxies. (United States)

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


    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.

  11. Auditory brainstem responses to clicks and tone bursts in C57 BL/6J mice. (United States)

    Scimemi, P; Santarelli, R; Selmo, A; Mammano, F


    In auditory research, hearing function of mouse mutants is assessed in vivo by evoked potential recording. Evaluation of the response parameters should be performed with reference to the evoked responses recorded from wild-type mice. This study reports normative data calculated on auditory brainstem responses (ABRs) obtained from 20 wild-type C57 BL/6J mice at a postnatal age between 21 and 45 days. Acoustic stimuli consisted tone bursts at 8, 14, 20, 26, 32 kHz, and clicks. Each stimulus was delivered in free field at stimulation intensity starting from a maximum of 100 dB peak equivalent SPL (dB peSPL) at decreasing steps of 10 dB with a repetition rate of 13/sec. Evoked responses were recorded by needle electrodes inserted subcutaneously. At high intensity stimulation, five response waveforms, each consisting of a positive peak and a subsequent negative valley, were identified within 7 msec, and were labelled with sequential capital Roman numerals from I to V. Peak IV was the most robust and stable at low intensities for both tone burst and click stimuli, and was therefore utilized to estimate hearing thresholds. Both latencies and amplitudes of ABR peaks showed good reproducibility with acceptable standard deviations. Mean wave IV thresholds measured across all animals ranged from a maximum of 23 dB peSPL for clicks to a minimum of 7 dB peSPL for 20 kHz-tone burst stimuli. Statistical analysis of the distribution of latencies and amplitudes of peaks from I to V performed for each stimulus type yielded a normative data set which was utilised to obtain the most consistent fitting-curve model. This could serve as a reference for further studies on murine models of hearing loss.

  12. clickECM: Development of a cell-derived extracellular matrix with azide functionalities. (United States)

    Ruff, S M; Keller, S; Wieland, D E; Wittmann, V; Tovar, G E M; Bach, M; Kluger, P J


    In vitro cultured cells produce a complex extracellular matrix (ECM) that remains intact after decellularization. The biological complexity derived from the variety of distinct ECM molecules makes these matrices ideal candidates for biomaterials. Biomaterials with the ability to guide cell function are a topic of high interest in biomaterial development. However, these matrices lack specific addressable functional groups, which are often required for their use as a biomaterial. Due to the biological complexity of the cell-derived ECM, it is a challenge to incorporate such functional groups without affecting the integrity of the biomolecules within the ECM. The azide-alkyne cycloaddition (click reaction, Huisgen-reaction) is an efficient and specific ligation reaction that is known to be biocompatible when strained alkynes are used to avoid the use of copper (I) as a catalyst. In our work, the ubiquitous modification of a fibroblast cell-derived ECM with azides was achieved through metabolic oligosaccharide engineering by adding the azide-modified monosaccharide Ac4GalNAz (1,3,4,6-tetra-O-acetyl-N-azidoacetylgalactosamine) to the cell culture medium. The resulting azide-modified network remained intact after removing the cells by lysis and the molecular structure of the ECM proteins was unimpaired after a gentle homogenization process. The biological composition was characterized in order to show that the functionalization does not impair the complexity and integrity of the ECM. The azides within this "clickECM" could be accessed by small molecules (such as an alkyne-modified fluorophore) or by surface-bound cyclooctynes to achieve a covalent coating with clickECM.

  13. Reengineering Antibiotics to Combat Bacterial Resistance: Click Chemistry [1,2,3]-Triazole Vancomycin Dimers with Potent Activity against MRSA and VRE. (United States)

    Silverman, Steven M; Moses, John E; Sharpless, K Barry


    Vancomycin has long been considered a drug of last resort. Its efficiency in treating multiple drug-resistant bacterial infections, particularly methicillin-resistant Staphylococcus aureus (MRSA), has had a profound effect on the treatment of life-threatening infections. However, the emergence of resistance to vancomycin is a cause for significant worldwide concern, prompting the urgent development of new effective treatments for antibiotic resistant bacterial infections. Harnessing the benefits of multivalency and cooperativity against vancomycin-resistant strains, we report a Click Chemistry approach towards reengineered vancomycin derivatives and the synthesis of a number of dimers with increased potency against MRSA and vancomycin resistant Enterococci (VRE; VanB). These semi-synthetic dimeric ligands were linked together with great efficiency using the powerful CuAAC reaction, demonstrating high levels of selectivity and purity.

  14. An SEMG computer interface using three myoelectric sites for proportional two-dimensional cursor motion control and clicking for individuals with spinal cord injuries. (United States)

    Choi, Changmok; Na, Youngjin; Rim, Byeongcheol; Kim, Youngkyung; Kang, Sangkuk; Kim, Jung


    We developed an alternative computer interface using surface electromyography (sEMG) for individuals with spinal cord injuries (SCI) to access a computer. We designed this interface to make a cursor move on a two-dimensional screen and to click using only three muscles for each subject. In addition, a user can voluntarily control cursor movement speed by modulating muscle contraction levels. Three SCI patients and 10 healthy subjects volunteered to evaluate the performance of this interface using Fitts' law test in a two-dimensional testing setup. The throughputs (TP) of our interface were 0.1962±0.0562 b/s for the SCI patients and 0.4356±0.0706 b/s for the healthy subjects. This interface could help SCI patients handle a wider range of activities such as browsing the Internet and communicating with others.

  15. Synthesis of amphiphilic aminated inulin via 'click chemistry' and evaluation for its antibacterial activity. (United States)

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


    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.

  16. Antiproliferative Activity of Polyether Antibiotic--Cinchona Alkaloid Conjugates Obtained via Click Chemistry. (United States)

    Skiera, Iwona; Antoszczak, Michał; Trynda, Justyna; Wietrzyk, Joanna; Boratyński, Przemysław; Kacprzak, Karol; Huczyński, Adam


    A series of eight new conjugates of salinomycin or monensin and Cinchona alkaloids were obtained by the Cu(I)-catalysed 1,3-dipolar Huisgen cycloaddition (click chemistry) of respective N-propargyl amides of salinomycin or monensin with four different Cinchona alkaloid derived azides. In vitro antiproliferative activity of these conjugates evaluated against three cancer cell lines (LoVo, LoVo/DX, HepG2) showed that four of the compounds exhibited high antiproliferative activity (IC50 below 3.00 μm) and appeared to be less toxic and more selective against normal cells than two standard anticancer drugs.

  17. Manufacturing of Peptide Microarrays Based on Catalyst-Free Click Chemistry. (United States)

    Prim, Denis; Pfeifer, Marc E


    Immobilization of peptides to a solid surface is frequently an important first step before they can be probed with a variety of biological samples in a heterogeneous assay format for research and clinical diagnostic purposes. Peptides can be derivatized in many ways to subsequently covalently attach them to an activated solid surface such as epoxy-functionalized glass slides. Here, we describe a clean, efficient, and reproducible fabrication process based on catalyst-free click chemistry compatible with the construction of low- to high-density peptide microarrays.

  18. Click chemistry decoration of amino sterols as promising strategy to developed new leishmanicidal drugs. (United States)

    Porta, Exequiel O J; Carvalho, Paulo B; Avery, Mitchell A; Tekwani, Babu L; Labadie, Guillermo R


    A series of 1,2,3-triazolylsterols was prepared from pregnenolone through reductive amination and copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry). The newly generated stereocenter of the key propargylamino intermediate provided a mixture of diastereomers which were separated chromatographically, and the configuration of the R isomer was determined by X-ray crystallography. Ten triazolyl sterols were prepared, and the products and intermediates were screened in vitro against different parasites, with some compounds presenting IC50 values in the low micromolar range against Leishmania donovani.

  19. Development of surface immobilized 3-azidocoumarin-based fluorogenic probe via strain promoted click chemistry. (United States)

    Bharathi, M Vijaya; Chhabra, Mohit; Paira, Priyankar


    A new class of imaging probe, a fluorogenic version of 1, 3-dipolar cycloaddition of azides and alkynes has been developed. 3-azidocoumarin scaffolds were selectively immobilized on the DBCO modified bead surface via SPAAC and provide direct and strong fluorescence in fluorescence microscopy. This developed click-on beads could be applied to label various biomolecules, such as nucleic acids, proteins and other molecules. To this end, 5'(7-hydroxy 3-azido coumarin) labelled DNA primer also displayed strong fluorescence upon successful immobilization on the bead surface.

  20. CuAAC: An Efficient Click Chemistry Reaction on Solid Phase. (United States)

    Castro, Vida; Rodríguez, Hortensia; Albericio, Fernando


    Click chemistry is an approach that uses efficient and reliable reactions, such as Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), to bind two molecular building blocks. CuAAC has broad applications in medicinal chemistry and other fields of chemistry. This review describes the general features and applications of CuAAC in solid-phase synthesis (CuAAC-SP), highlighting the suitability of this kind of reaction for peptides, nucleotides, small molecules, supramolecular structures, and polymers, among others. This versatile reaction is expected to become pivotal for meeting future challenges in solid-phase chemistry.

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

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbæk; Yu, Donghong

    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......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...

  2. Copper-chelating azides for efficient click conjugation reactions in complex media. (United States)

    Bevilacqua, Valentina; King, Mathias; Chaumontet, Manon; Nothisen, Marc; Gabillet, Sandra; Buisson, David; Puente, Céline; Wagner, Alain; Taran, Frédéric


    The concept of chelation-assisted copper catalysis was employed for the development of new azides that display unprecedented reactivity in the copper(I)-catalyzed azide-alkyne [3+2] cycloaddition (CuAAC) reaction. Azides that bear strong copper-chelating moieties were synthesized; these functional groups allow the formation of azide copper complexes that react almost instantaneously with alkynes under diluted conditions. Efficient ligation occurred at low concentration and in complex media with only one equivalent of copper, which improves the biocompatibility of the CuAAC reaction. Furthermore, such a click reaction allowed the localization of a bioactive compound inside living cells by fluorescence measurements.



    Leonardo Linguaglossa; Alfio Lombardo; Diego Reforgiato; Giovanni Schembra


    1It is possible to forward minimum-sized packets at rates of hundreds of Mbps using commodity hardware and Linux. We had a preference for the Click Modular Router platform due its flexibility and the fact that it claimed to have equal or higher performance than native forwarding if used with its polling drivers. Moreover, the NetFPGA is an open networking platform accelerator that enables researchers and instructors to build working prototypes of high-speed, hardware-accelerated networking sy...

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

    KAUST Repository

    Solovyeva, Vera A.


    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.

  5. "Clip" and "click" chemistries combination: toward easy PEGylation of degradable aliphatic polyesters. (United States)

    Freichels, Hélène; Pourcelle, Vincent; Le Duff, Cécile S; Marchand-Brynaert, Jacqueline; Jérôme, Christine


    α-Methoxy-ω-alkyne poly(ethylene glycol) (PEG) was tagged with pendent N-hydroxy-succinimidyl activated esters by photografting of a molecular clip. This easily synthesized heterofunctional PEG was found to be a versatile building block for (i) conjugation with an amino derivative and (ii) grafting to azido functional aliphatic polyesters backbone by Huisgen's 1,3-dipolar cycloaddition. This original combination of "clip" and "click" reactions provides a versatile and straightforward pathway for the synthesis of functional amphiphilic and degradable copolymers valuable for biomedical applications such as in drug-delivery.

  6. Synthesis of Farnesol Analogues Containing Triazoles in Place of Isoprenes through 'Click Chemistry' (United States)

    Subramanian, Thangaiah; Parkin, Sean; Spielmann, H Peter


    A solid-phase three-component Huisgen reaction has been used to generate polar farnesol and farnesyl diphosphate analogues. The Cu(I)-catalyzed 1,3-cycloadditions of various azides with solid supported (E)-3-methylhept-2-en-6-yn-1-ol provided only the 1,4-disubstituted 1,2,3-triazole regioisomers. The organic azides were generated in situ to minimize handling of potentially explosive azides. We have employed this powerful 'click chemistry' to make farnesol analogues where both β- and γ-isoprenes were replaced by triazole and substituted aromatic rings, respectively.

  7. Synthesis of Farnesol Analogues Containing Triazoles in Place of Isoprenes through ‘Click Chemistry’ (United States)

    Subramanian, Thangaiah; Parkin, Sean


    A solid-phase three-component Huisgen reaction has been used to generate polar farnesol and farnesyl diphosphate analogues. The Cu(I)-catalyzed 1,3-cycloadditions of various azides with solid supported (E)-3-methylhept-2-en-6-yn-1-ol provided only the 1,4-disubstituted 1,2,3-triazole regioisomers. The organic azides were generated in situ to minimize handling of potentially explosive azides. We have employed this powerful ‘click chemistry’ to make farnesol analogues where both β- and γ-isoprenes were replaced by triazole and substituted aromatic rings, respectively. PMID:23125482

  8. 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)


    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

  9. One-Click Data Analysis Software for Science Operations (United States)

    Navarro, Vicente


    One of the important activities of ESA Science Operations Centre is to provide Data Analysis Software (DAS) to enable users and scientists to process data further to higher levels. During operations and post-operations, Data Analysis Software (DAS) is fully maintained and updated for new OS and library releases. Nonetheless, once a Mission goes into the "legacy" phase, there are very limited funds and long-term preservation becomes more and more difficult. Building on Virtual Machine (VM), Cloud computing and Software as a Service (SaaS) technologies, this project has aimed at providing long-term preservation of Data Analysis Software for the following missions: - PIA for ISO (1995) - SAS for XMM-Newton (1999) - Hipe for Herschel (2009) - EXIA for EXOSAT (1983) Following goals have guided the architecture: - Support for all operations, post-operations and archive/legacy phases. - Support for local (user's computer) and cloud environments (ESAC-Cloud, Amazon - AWS). - Support for expert users, requiring full capabilities. - Provision of a simple web-based interface. This talk describes the architecture, challenges, results and lessons learnt gathered in this project.

  10. Click Chemistry Route to the Synthesis of Unusual Amino Acids, Peptides, Triazole-Fused Heterocycles and Pseudodisaccharides. (United States)

    Chandrasekaran, Srinivasan; Ramapanicker, Ramesh


    Conjugation of different molecular species using copper(I)-catalyzed click reaction between azides and terminal alkynes is among the best available methods to prepare multifunctional compounds. The effectiveness of this method has provided wider acceptance to the concept of click chemistry, which is now widely employed to synthesize densely functionalized organic molecules. This article summarizes the contributions from our group in the development of new methods for the synthesis of functional molecules using copper(I)-catalyzed click reactions. We have developed very efficient methods for the synthesis of peptides and amino acids conjugated with carbohydrates, thymidine and ferrocene. We have also developed an efficient strategy to synthesize triazole-fused heterocycles from primary amines, amino alochols and diols. Finally, an interesting method for the synthesis of pseudodisaccharides linked through triazoles, starting from carbohydrate-derived donor-acceptor cyclopropanes is discussed.

  11. Effects of Beliefs and Concerns on User Attitudes toward Online Social Network Advertising and Their Ad Clicking Behavior

    Directory of Open Access Journals (Sweden)

    Imran Mir


    Full Text Available Since last few years social network sites (SNSs have rapidly grown in popularity and user acceptance globally. They have become the main place for social interaction, discussion and communication. Today, many businesses advertise their products on SNSs. The current study aims to assess the effects of SNSs consumers/users’ beliefs and concerns of social network advertising (SNA on their attitudes toward SNA and SNS banner ad-clicking behavior. Data was collected from a sample of 397 university students of Pakistan. Results show the beliefs of SNA as informative and entertaining have positive effects on user attitudes toward SNA and their ad-clicking behavior. Similarly, user concern of SNA as irritating has negative effects on both their attitudes toward SNA and ad-clicking behavior. Good for economy is an important socioeconomic belief which affects user attitudes toward SNA positively. The overall results indicate that utilitarian and hedonic aspects of SNA make SNS banner ads effective.

  12. On-demand electrochemical activation of the click reaction on self-assembled monolayers on gold presenting masked acetylene groups. (United States)

    Choi, Inseong; Kim, Young-Kwan; Min, Dal-Hee; Lee, SangWook; Yeo, Woon-Seok


    We report on a new surface modification method for grafting a "dynamic" property for on-demand activation of the click reaction. Our approach utilizes the acetylene group masked with dicobalt hexacarbonyl, Co(2)(CO)(6), which is not reactive toward the click reaction. Electrochemical treatment reveals the acetylene group on the selected region, which is then used as a chemical handle for surface functionalization via the click reaction with an azide-containing molecule. Electrochemical and chemical conversions on the surface were verified by cyclic voltammetry, X-ray photoelectron spectroscopy, and fluorescence spectroscopy. We have demonstrated immobilization of an azide-modified RGD peptide and promotion of cell adhesion/migration to the region of electrochemical induction.

  13. Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in sediments of Liaohe River: levels, spatial and temporal distribution, possible sources, and inventory. (United States)

    Lv, Jiapei; Zhang, Yuan; Zhao, Xin; Zhou, Changbo; Guo, Changsheng; Luo, Yi; Meng, Wei; Zou, Guofang; Xu, Jian


    Spatial and seasonal variations of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in the sediment of Liaohe River were investigated in this study. A total of 29 surface sediment samples were collected in May and September in 2013. Results showed that levels of the two classes of compounds were higher in September than in May. The total concentration of PBDEs (∑8PBDEs) ranged from 0.30 to 5.09 ng g(-1) in May and from 0.17 to 13.73 ng g(-1) in September, respectively, and BDE 209 was the dominant compound. The total concentration of PCBs (∑33PCBs) was in the range of 4.92-76.86 and 11.69-179.61 ng g(-1) in May and September, respectively, with tri- and tetra-CBs dominated in the total PCBs in the sediments. According to the congener profiles and the principal component analysis, the major sources of PCBs and PBDEs in sediments of Liaohe River were from the usage of commercial products and industrial activities, and the degradation of high brominated BDEs also contributed to the current PBDEs in the sediments. The mass inventories of PBDEs and PCBs in the sediments of Liaohe River were 1.74 and 21.96 t, respectively, indicating that Liaohe River sediments may act as the potential sources of PBDEs and PCBs to the downstream coastal areas.

  14. Lanthanide complexes of azidophenacyl-DO3A as new synthons for click chemistry and the synthesis of heterometallic lanthanide arrays. (United States)

    Tropiano, Manuel; Kenwright, Alan M; Faulkner, Stephen


    Lanthanide complexes of azidophenacyl DO3A are effective substrates for click reactions with ethyne derivatives, giving rise to aryl triazole appended lanthanide complexes, in which the aryl triazole acts as an effective sensitising chromophore for lanthanide luminescence. They also undergo click chemistry with propargylDO3A derivatives, giving rise to heterometallic complexes.

  15. Just Click It: Undergraduate Procedures for the Copper(I)-Catalyzed Formation of 1,2,3-Triazoles from Azides and Terminal Acetylenes (United States)

    Sharpless, William D.; Peng Wu; Hansen, Trond Vidar; Lindberg, James G.


    The click chemistry uses only the most reliable reactions to build complex molecules from olefins, electrophiles and heteroatom linkers. A variation on Huisgen's azide-alkyne 1,2,3-triazole synthesis, the addition of the copper (I), the premium example of the click reaction, catalyst strongly activates terminal acetylenes towards the 1,3-dipole in…

  16. Multi-scale modeling study of the source contributions to near-surface ozone and sulfur oxides levels over California during the ARCTAS-CARB period

    Directory of Open Access Journals (Sweden)

    M. Huang


    Full Text Available Chronic ozone (O3 problems and the increasing sulfur oxides (SOx=SO2+SO4 ambient concentrations over South Coast (SC and other areas of California (CA are affected by both local emissions and long-range transport. In this paper, multi-scale tracer and full-chemistry simulations with the STEM atmospheric chemistry model are used to assess the contribution of local emission sources to SC O3 and evaluate the impacts of transported sulfur and local emissions on the SC sulfur budget during the ARCTAS-CARB experiment period in 2008. Sensitivity simulations quantify contributions of biogenic and fire emissions to SC O3 levels. California biogenic and fire emissions contribute 3–4 ppb to near-surface O3 over SC, with larger contributions to other regions in CA. Long-range transport from Asia is estimated to enhance surface SO4 over SC by ~0.5 μg/sm3, and the higher SOx levels (up to ~0.7 ppb of SO2 and ~6 μg/sm3 of SO4 observed above ~6 km did not affect surface air quality in the study region. Enhanced near-surface SOx levels over SC during the flight week were attributed mostly to local emissions. Two anthropogenic SOx emission inventories (EIs from the California Air Resources Board (CARB and the US Environmental Protection Agency (EPA are compared and applied in 60 km and 12 km chemical transport simulations, and the results are compared with observations. The CARB EI shows improvements over the National Emission Inventory (NEI by EPA, but generally underestimates surface SC SOx by about a factor of two. Maritime (mostly shipping emissions contribute to the high SO2 levels over the ocean and on-shore, and fine SO4 over the downwind areas is impacted by maritime sources. Maritime emissions also modify the NOx-VOC limitations over coastal

  17. A photoreducible copper(II)-tren complex of practical value: generation of a highly reactive click catalyst. (United States)

    Harmand, Lydie; Lambert, Romain; Scarpantonio, Luca; McClenaghan, Nathan D; Lastécouères, Dominique; Vincent, Jean-Marc


    A detailed study on the photoreduction of the copper(II) precatalyst 1 to generate a highly reactive cuprous species for the copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) click reaction is presented. For the photoactive catalyst described herein, the activation is driven by a photoinduced electron transfer (PET) process harnessing a benzophenone-like ketoprofenate chromophore as a photosensitizer, which is equally the counterion. The solvent is shown to play a major role in the Cu(II) to Cu(I) reduction process as the final electron source, and the influence of the solvent nature on the photoreduction efficiency has been studied. Particular attention was paid to the use of water as a potential solvent, aqueous media being particularly appealing for CuAAC processes. The ability to solubilize the copper-tren complexes in water through the formation of inclusion complexes with β-CDs is demonstrated. Data is also provided on the fate of the copper(I)-tren catalytic species when reacting with O2, O2 being used to switch off the catalysis. These data show that partial oxidation of the secondary benzylamine groups of the ligand to benzylimines occurs. Preliminary results show that when prolonged irradiation times are employed a Cu(I) to Cu(0) over-reduction process takes place, leading to the formation of copper nanoparticles (NPs). Finally, the main objective of this work being the development of photoactivable catalysts of practical value for the CuAAC, the catalytic, photolatent, and recycling properties of 1 in water and organic solvents are reported.

  18. Changing dietary calcium-phosphorus level and cereal source selectively alters abundance of bacteria and metabolites in the upper gastrointestinal tracts of weaned pigs. (United States)

    Metzler-Zebeli, Barbara U; Mann, Evelyne; Schmitz-Esser, Stephan; Wagner, Martin; Ritzmann, Mathias; Zebeli, Qendrim


    Several dietary ingredients may affect the bacterial community structure and metabolism in the porcine gut and may therefore influence animals' health and performance. This study investigated the effects of cereal source and calcium-phosphorus (CaP) level in the diet on bacterial microbiota and metabolites, nutrient intake, and gut environment in weaned pigs. Pigs (n=8/treatment) were fed wheat-barley- or corn-based diets with an adequate or high CaP level for 14 days. Effects on microbiota in the stomach, ileum, and midcolon were assessed using quantitative PCR. Data showed that Enterobacteriaceae, Campylobacter spp., and Helicobacter spp., which all contain highly immune reactive lipopolysaccharide (LPS), were abundant at all gut sites. Diet effects on bacteria and metabolites were moderate and occurred mainly in the upper gut, whereas no effects on bacteria, fermentation products, and LPS could be observed in the colon. Differences in carbohydrate intake with corn versus wheat-barley diets selectively stimulated Bifidobacterium in the stomach and ileum. There was a growth advantage for a few bacterial groups in the stomach and ileum of pigs fed the high versus adequate CaP level (i.e., gastric Enterobacteriaceae and ileal Enterococcus, Bacteroides-Prevotella-Porphyromonas, and Campylobacter). Interestingly, gastrointestinal pH was not affected by dietary CaP level. The present findings demonstrate the stability of the bacterial community and gut environment toward dietary changes even in young pigs. The results on stimulation of gastric and ileal Bifidobacterium by corn diets may be employed in nutritional strategies to support gut health after weaning.

  19. Healthy Zero Energy Buildings (HZEB) Program - Cross-Sectional Study of Contaminant Levels, Source, Strengths, and Ventilation Rates in Retail Stores

    Energy Technology Data Exchange (ETDEWEB)

    Chan, Wanyu R.; Sidheswaran, Meera; Cohn, Sebastian; Sullivan, Douglas P.; Fisk, William


    then used to determine the ventilation rates, filtration strategies, or source reductions needed to maintain indoor contaminant concentrations below reference levels. Several scenarios of potential concern were considered: (i) formaldehyde levels in furniture/hardware stores, (ii) contaminants associated with cooking (e.g., PM, acrolein, and acetaldehyde) in grocery stores, and (iii) outdoor contaminants (e.g., PM and O{sub 3}) impacting stores that use natural ventilation. Estimated formaldehyde emission rates suggest that retail stores would need to ventilate at levels far exceeding the current Title 24 requirement to lower indoor concentrations below California’s stringent formaldehyde reference level. Given the high costs of providing ventilation but only modest chronic health benefit is expected, effective source control is an attractive alternative, as demonstrated by some retail stores in this study. Predictions showed that grocery stores need MERV 13 air filters, instead of MERV 8 filters that are more commonly used, to maintain indoor PM at levels that meet the chronic health standards for PM. Exposure to acrolein is a potential health concern in grocery stores, and should be addressed by increasing the use of kitchen range hoods or improving their contaminant removal efficiency. In stores that rely on natural ventilation, indoor PM can be a health concern if the stores are located in areas with high outdoor PM. This concern may be addressed by switching to mechanical ventilation when the outdoor air quality is poor, while continuing natural ventilation when outdoor air quality is good.

  20. The Influence of Language Experience on Contralateral Suppression of Click-Evoked Otoacoustic Emissions in Young Adults (United States)

    Bhagat, Shaum P.; Xu, Jingjing


    Click-evoked otoacoustic emissions (CEOAEs) were recorded from the right ear of eight native Mandarin speakers and eight native English speakers in conditions with and without a contralateral suppressor. The CEOAE stimuli consisted of linear clicks presented at 65 dB peSPL. Two types of 70 dB SPL contralateral suppressors (white noise and synthesized Mandarin tone) were utilized. The amount of contralateral suppression was quantified in nine 2-ms time bands. No significant differences in contralateral suppression occurred between language groups for the white noise suppressor. Notably, significantly more contralateral suppression was evoked by the synthesized Mandarin tone in native Mandarin speakers compared to native English speakers.