Green synthesis of ZnSe and core–shell ZnSe@ZnS nanocrystals (NCs) using a new, rapid and room temperature photochemical approach

Energy Technology Data Exchange (ETDEWEB)

Molaei, M., E-mail: m.molaei@vru.ac.ir; Bahador, A.R.; Karimipour, M.

2015-10-15

In this work, ZnSe and core–shell ZnSe@ZnS nanocrystals (NCs) were synthesized using a one-pot, rapid and room temperature photochemical method. UV illumination provided the required energy for the chemical reactions. Synthesized NCs were characterized using X-ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), UV–vis and photoluminescence (PL) spectroscopy. XRD pattern indicated cubic zinc blende structure for ZnSe NCs and the TEM image indicated round-shaped particles, most of which had a diameter of about 3 nm. Band gap of ZnSe NCs was obtained as about 3.6 eV, which was decreased by increasing the illumination time. Synthesized NCs indicated intensive and narrow emission in the UV-blue area (370 nm) related to the excitonic recombination and a broad band emission with a peak located at about 490 nm originated from the DAP (donor–acceptor pairs) recombination. ZnS shell was grown on ZnSe cores using a reaction based on the photo-sensitivity of Na{sub 2}S{sub 2}O{sub 3}. For ZnSe@ZnS core–shell NCs, XRD diffraction peaks shifted to higher angles. TEM image indicated a shell around cores and most of the ZnSe@ZnS NCs have a diameter of about 5 nm. After the ZnS growth, ZnSe excitonic emission shifted to the longer wavelength and PL intensity was increased considerably. PL QY was obtained about 11% and 17% for ZnSe and ZnSe@ZnS core–shell QDs respectively. - Highlights: • A green photochemical approach was reported for synthesis of ZnSe NCs. • ZnS shell was grown around ZnSe using a new method. • Synthesis method was rapid, simple and at room temperature. • ZnSe NCs indicated a narrow UV-blue and a broad DAP emissions. • PL intensity was increased considerably by ZnS shell growth.

The solute specificity profiles of nucleobase cation symporter 1 (NCS1) from Zea mays and Setaria viridis illustrate functional flexibility.

Science.gov (United States)

Rapp, Micah; Schein, Jessica; Hunt, Kevin A; Nalam, Vamsi; Mourad, George S; Schultes, Neil P

2016-03-01

The solute specificity profiles (transport and binding) for the nucleobase cation symporter 1 (NCS1) proteins, from the closely related C4 grasses Zea mays and Setaria viridis, differ from that of Arabidopsis thaliana and Chlamydomonas reinhardtii NCS1. Solute specificity profiles for NCS1 from Z. mays (ZmNCS1) and S. viridis (SvNCS1) were determined through heterologous complementation studies in NCS1-deficient Saccharomyces cerevisiae strains. The four Viridiplantae NCS1 proteins transport the purines adenine and guanine, but unlike the dicot and algal NCS1, grass NCS1 proteins fail to transport the pyrimidine uracil. Despite the high level of amino acid sequence similarity, ZmNCS1 and SvNCS1 display distinct solute transport and recognition profiles. SvNCS1 transports adenine, guanine, hypoxanthine, cytosine, and allantoin and competitively binds xanthine and uric acid. ZmNCS1 transports adenine, guanine, and cytosine and competitively binds, 5-fluorocytosine, hypoxanthine, xanthine, and uric acid. The differences in grass NCS1 profiles are due to a limited number of amino acid alterations. These amino acid residues do not correspond to amino acids essential for overall solute and cation binding or solute transport, as previously identified in bacterial and fungal NCS1, but rather may represent residues involved in subtle solute discrimination. The data presented here reveal that within Viridiplantae, NCS1 proteins transport a broad range of nucleobase compounds and that the solute specificity profile varies with species.

The effect of NCS- on the radiation-induced decoloration of azo and anthraquinone dyes in N2O-saturated aqueous solutions

International Nuclear Information System (INIS)

Suzuki, Nobutake; Hotta, Hiroshi

1977-01-01

The radiation-induced decoloration of azo and anthraquinone dyes was studied in N 2 O-saturated aqueous solutions containing NCS - . In the N 2 O-saturated solutions, the decoloration yield, G(-Dye), increased markedly upon the addition of NCS - , which is an efficient scavenger of the OH radical-that is, from 1.46 up to 2.10 for Acid Red 265 and from 0.51 up to 1.51 for Acid Blue 40 upon the addition of 1 mM NCS - . In the nitrogen-saturated solutions, however, the G(-Dye) decreased upon the addition of NCS - . It is concluded that the increase in the G(-Dye) upon the addition of NCS - in the N 2 O-saturated solutions is mainly attributable to the attack of the radical anion (NCS) 2 - on the ring structure of the dyes. This radical anion is formed through the following path: NCS - +OH → NCS+OH - and NCS+NCS - reversible (NCS) 2 - . At low NCS - concentrations, the G(-Dye) decreased for Acid Red 265 and increased for Acid Blue 40. This may be attributable to the larger reactivity of (NCS) 2 - on Acid Blue 40 than on Acid Red 265. (auth.)

Modelling the protocol stack in NCS with deterministic and stochastic petri net

Science.gov (United States)

Hui, Chen; Chunjie, Zhou; Weifeng, Zhu

2011-06-01

Protocol stack is the basis of the networked control systems (NCS). Full or partial reconfiguration of protocol stack offers both optimised communication service and system performance. Nowadays, field testing is unrealistic to determine the performance of reconfigurable protocol stack; and the Petri net formal description technique offers the best combination of intuitive representation, tool support and analytical capabilities. Traditionally, separation between the different layers of the OSI model has been a common practice. Nevertheless, such a layered modelling analysis framework of protocol stack leads to the lack of global optimisation for protocol reconfiguration. In this article, we proposed a general modelling analysis framework for NCS based on the cross-layer concept, which is to establish an efficiency system scheduling model through abstracting the time constraint, the task interrelation, the processor and the bus sub-models from upper and lower layers (application, data link and physical layer). Cross-layer design can help to overcome the inadequacy of global optimisation based on information sharing between protocol layers. To illustrate the framework, we take controller area network (CAN) as a case study. The simulation results of deterministic and stochastic Petri-net (DSPN) model can help us adjust the message scheduling scheme and obtain better system performance.

An ontology-based nurse call management system (oNCS) with probabilistic priority assessment

Science.gov (United States)

2011-01-01

Background The current, place-oriented nurse call systems are very static. A patient can only make calls with a button which is fixed to a wall of a room. Moreover, the system does not take into account various factors specific to a situation. In the future, there will be an evolution to a mobile button for each patient so that they can walk around freely and still make calls. The system would become person-oriented and the available context information should be taken into account to assign the correct nurse to a call. The aim of this research is (1) the design of a software platform that supports the transition to mobile and wireless nurse call buttons in hospitals and residential care and (2) the design of a sophisticated nurse call algorithm. This algorithm dynamically adapts to the situation at hand by taking the profile information of staff members and patients into account. Additionally, the priority of a call probabilistically depends on the risk factors, assigned to a patient. Methods The ontology-based Nurse Call System (oNCS) was developed as an extension of a Context-Aware Service Platform. An ontology is used to manage the profile information. Rules implement the novel nurse call algorithm that takes all this information into account. Probabilistic reasoning algorithms are designed to determine the priority of a call based on the risk factors of the patient. Results The oNCS system is evaluated through a prototype implementation and simulations, based on a detailed dataset obtained from Ghent University Hospital. The arrival times of nurses at the location of a call, the workload distribution of calls amongst nurses and the assignment of priorities to calls are compared for the oNCS system and the current, place-oriented nurse call system. Additionally, the performance of the system is discussed. Conclusions The execution time of the nurse call algorithm is on average 50.333 ms. Moreover, the oNCS system significantly improves the assignment of nurses

An ontology-based nurse call management system (oNCS with probabilistic priority assessment

Directory of Open Access Journals (Sweden)

Verhoeve Piet

2011-02-01

Full Text Available Abstract Background The current, place-oriented nurse call systems are very static. A patient can only make calls with a button which is fixed to a wall of a room. Moreover, the system does not take into account various factors specific to a situation. In the future, there will be an evolution to a mobile button for each patient so that they can walk around freely and still make calls. The system would become person-oriented and the available context information should be taken into account to assign the correct nurse to a call. The aim of this research is (1 the design of a software platform that supports the transition to mobile and wireless nurse call buttons in hospitals and residential care and (2 the design of a sophisticated nurse call algorithm. This algorithm dynamically adapts to the situation at hand by taking the profile information of staff members and patients into account. Additionally, the priority of a call probabilistically depends on the risk factors, assigned to a patient. Methods The ontology-based Nurse Call System (oNCS was developed as an extension of a Context-Aware Service Platform. An ontology is used to manage the profile information. Rules implement the novel nurse call algorithm that takes all this information into account. Probabilistic reasoning algorithms are designed to determine the priority of a call based on the risk factors of the patient. Results The oNCS system is evaluated through a prototype implementation and simulations, based on a detailed dataset obtained from Ghent University Hospital. The arrival times of nurses at the location of a call, the workload distribution of calls amongst nurses and the assignment of priorities to calls are compared for the oNCS system and the current, place-oriented nurse call system. Additionally, the performance of the system is discussed. Conclusions The execution time of the nurse call algorithm is on average 50.333 ms. Moreover, the oNCS system significantly improves

Molecular basis of substrate promiscuity for the SAM-dependent O-methyltransferase NcsB1, involved in the biosynthesis of the enediyne antitumor antibiotic neocarzinostatin.

Science.gov (United States)

Cooke, Heather A; Guenther, Elizabeth L; Luo, Yinggang; Shen, Ben; Bruner, Steven D

2009-10-13

The small molecule component of chromoprotein enediyne antitumor antibiotics is biosynthesized through a convergent route, incorporating amino acid, polyketide, and carbohydrate building blocks around a central enediyne hydrocarbon core. The naphthoic acid moiety of the enediyne neocarzinostatin plays key roles in the biological activity of the natural product by interacting with both the carrier protein and duplex DNA at the site of action. We have previously described the in vitro characterization of an S-adenosylmethionine-dependent O-methyltransferase (NcsB1) in the neocarzinostatin biosynthetic pathway [Luo, Y., Lin, S., Zhang, J., Cooke, H. A., Bruner, S. D., and Shen, B. (2008) J. Biol. Chem. 283, 14694-14702]. Here we provide a structural basis for NcsB1 activity, illustrating that the enzyme shares an overall architecture with a large family of S-adenosylmethionine-dependent proteins. In addition, NcsB1 represents the first enzyme to be structurally characterized in the biosynthetic pathway of neocarzinostatin. By cocrystallizing the enzyme with various combinations of the cofactor and substrate analogues, details of the active site structure have been established. Changes in subdomain orientation were observed via comparison of structures in the presence and absence of substrate, suggesting that reorientation of the enzyme is involved in binding of the substrate. In addition, residues important for substrate discrimination were predicted and probed through site-directed mutagenesis and in vitro biochemical characterization.

Synthesis and characterization of rare-earth-doped calcium tungstate nanocrystals

Science.gov (United States)

Suneeta, P.; Rajesh, Ch.; Ramana, M. V.

2018-02-01

In this paper, we report synthesis and characterization of rare-earth-ion-doped calcium tungstate (CaWO4) nanocrystals (NCs). Rare-earth ions, such as gadolinium (Gd), neodymium (Nd), praseodymium (Pr), samarium (Sm) and holmium (Ho), were successfully doped in the CaWO4 NCs by changing the synthesis conditions. The adopted synthesis route was found to be fast and eco-friendly. Structural characterizations, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and compositional analysis, were performed using energy dispersive analysis of X-rays (EDAX) on as-synthesized NCs. The results indicate the size of the NCs ranging between 47 to 68nm and incorporation of rare-earth ions in CaWO4 NCs.

Regeneration of Used Frying Palm Oil with Coffee Silverskin (CS), CS Ash (CSA) and Nanoparticles of CS (NCS).

Science.gov (United States)

Ismail, Samir Abd-Elmonem A; El-Anany, Ayman Mohammed; Ali, Rehab Farouk M

2017-01-01

The present investigation aimed to evaluate the efficiency of coffee silverskin (CS), CS ash (CSA) and nanoparticles of CS (NCS) in regeneration the quality of used frying palm oil. The adsorbents were mixed individually with used frying palm oil at level 4% (w/v) for 60 min. The properties of CS, CSA and NCS adsorbents were studied using (SEM) scanning electron microscopy technique. Some of physico-chemical characteristics of used frying palm oil (UFPO) and UFPO treated with adsorbents were determined. The results showed that the CS ash particles composed of irregular spherical and semispherical grains with deep cavities. The size of particles of CS ash ranged in diameter from 1.1 to 1.7 µm. The morphology of NCS consisted of cluster-type spherical nanoparticles and flakes. The particle size of NCS varies from 0.9 to 1.7 µm. Purification treatments caused marked (poil compared to untreated oil. The treatment of UFPO with 4% of adsorbents caused significant reductions in the content of free fatty acids ranged from 51.2 to 65.0%. The lowest level of peroxide (2.1 meq/kg) was recorded for UFPO treated with 4% of NCS. The highest reductions (72.8; 70.0%) in p-anisidine value were observed in UFPO treated with 4% of CSA and NCS, respectively. Treatment of UFPO with 4% of CS, CSA and NCS significantly lowered the polar content from 13.9% to 6.3, 4.8 and 3.9%, respectively. The results also indicate that CSA and NCS have nearly the same adsorption efficiency in lowering polymer content of UFPO. Filtration treatment of UFPO with 4% of CS, CSA and NCS markedly lowered the viscosity and colour values of treated UFPO.

N-Chlorosuccinimide (NCS): A Novel Initiator for Atom Transfer Radical Polymerization of Methyl Methacrylate

Institute of Scientific and Technical Information of China (English)

WANG,Xia-Yan; CHANG,Li-Qun; ZHOU,Hong; ZHANG,Ke-Da

2006-01-01

Atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) was achieved, using N-chlorosuccinimide (NCS) as an initiator together with catalytic system CuCl/PMDETA (N,N,N',N',N"-pentamethyldiethyl-enetriamine), CuCl/MA5-DETA (N,N,N',N',N"-penta(methylacrylate)diethylenetriamine), and CuCl/bipy (bipy=2,2'-bipyridyl) respectively. The results indicated that the polymerization possessed typical controlled/living radical polymerization characteristics. The analysis for terminal group of obtained polymer by 1H NMR proved that NCS is an initiator for ATRP. In comparison with NBS, the polymerization rate was slower and the resulted polymer had narrower molecular weight distribution (MWD) when NCS was employed as the initiator.

Silicon-containing polymer-derived ceramic nanocomposites (PDC-NCs): preparative approaches and properties.

Science.gov (United States)

Ionescu, Emanuel; Kleebe, Hans-Joachim; Riedel, Ralf

2012-08-07

Composites consist by definition of at least two materials (Gibbsian phases) with rather different properties. They exhibit a heterogeneous microstructure and possess improved properties with respect to their components. Furthermore, the design of their microstructure allows for tailoring their overall properties. In the last decades, intense work was performed on the synthesis of nanocomposites, which have the feature that at least one of their components is nanoscaled. However, the microstructure-property relationship of nanocomposite materials is still a challenging topic. This tutorial review paper deals with a special class of nanocomposites, i.e. polymer-derived ceramic nanocomposites (PDC-NCs), which have been shown to be promising materials for various structural and functional applications. Within this context, different preparative approaches for PDC-NCs as well as some of their properties will be presented and discussed. Furthermore, recent results concerning the relationship between the nano/microstructure of PDC-NCs and their properties will be highlighted.

Spectroscopic and quantum-chemical investigation of association of ions in acetonitrile - LiX (X=I, ClO4, NCS) systems

International Nuclear Information System (INIS)

Semenov, S.G.; Solov'eva, L.A.; Akopyan, S.Kh.

1995-01-01

Data on association constants of ions in acetonitrile-salt binary systems, obtained from the data on intensity of IR absorption bands of acetonitrile (Acn) molecules contained in solvate shells of Li + cations, have been analyzed. Using the CCP MO LCAO semiempirical method in the PPDP approximation, electronic structure of acetonitrile molecule and Acn k Li + and Acn m Li + X - complexes has been studied. It is ascertained that relative stability of ionic pairs Acn 3 Li + X - , estimated by the squares of their dipole momenta (characterizing solvation energy) increases in the series X=I, ClO 4 , NCS in agreement with data of spectroscopic experiment, according to which the constant of ion association for LiNCS solution in acetonitrile is much higher than for the systems CH 3 CN-LiI and CH 3 CN-LiClO 4 . 13 refs.,2 figs., 2 tabs.64

University of New Mexico short course in nuclear criticality safety: Training for new NCS [nuclear criticality safety] specialists

International Nuclear Information System (INIS)

Busch, R.D.

1990-01-01

Since 1973, the University of New Mexico (UNM) has given ten short courses in nuclear criticality safety (NCS). Generally, thee have been given every other year, although in 1989 it was decided to offer the course on an annual basis. This decision was primarily based on the large demand for NCS specialists and a large turnover rate in the industry. The purpose of the course is to provide a 1-week overview of NCS. The typical student has been involved in NCS for <1 yr, although it many cases they have been associated with the nuclear industry in other capacities for many years. The short course is conducted at several levels. Carefully prepared lectures provide the information framework for selected topics. The following topics are covered in the course: basic reactor theory, criticality accidents and consequences, hand calculations, administration of a criticality safety program, regulators and their processes, computer methods and applications, experimental methods and correlations, overview of some process operations, and transportation and storage issues in NCS

Fabrication of Eu-TiO2 NCs functionalized cotton textile as a multifunctional photocatalyst for dye pollutants degradation

Science.gov (United States)

Caschera, Daniela; Federici, Fulvio; de Caro, Tilde; Cortese, Barbara; Calandra, Pietro; Mezzi, Alessio; Lo Nigro, Raffaella; Toro, Roberta G.

2018-01-01

A modified one step and cost-effective chemical green route has been used to synthesize oleate-capped TiO2 anatase nanocrystals (NCs) doped with different amounts of europium, with high yields and without high-temperature post-calcination processes. Europium doping endowed TiO2 NCs with an intense red luminescence associated with the 5D0 → 7F2 transition of the electronic structure of Eu3+ and was responsible for both the morphological change of the NCs structure (from nanorods to spherical nanoparticles) and the blue shift in the absorption edge respect to the undoped TiO2 NCs. Furthermore, photocatalytic experiments revealed that a low-content (0.5 mol%) Eu3+ doped TiO2 NCs showed the best ability as photocatalyst for the degradation of methylene blue (MB) under both UV and visible light irradiation, even if all the Eu3+ doped oleate-capped TiO2 NCs were more effective under visible light. Moreover, taking advantage of their photocatalytic activity, the 0.5% Eu3+ doped oleate-capped TiO2 photocatalysts has been employed on cotton fabrics. Our results highlighted that functionalization of cotton textile with Eu3+ doped oleate-capped TiO2 NCs imparted new functionalities, such as a high photocatalytic activity toward MB degradation under visible light. In addition, it determined also the change in the wetting behaviour of cotton that switches to a superhydrophobic nature. The obtained fabric also showed stable and robust superhydrophobicity against strong acid and alkaline environments. Multifunctional materials having simultaneously luminescence, superhydrophobicity and visible light photocatalysis are expected to be very useful in many technological applications.

NCS-1 associates with adenosine A2A receptors and modulates receptor function

Directory of Open Access Journals (Sweden)

Gemma eNavarro

2012-04-01

Full Text Available Modulation of G protein-coupled receptor (GPCR signalling by local changes in intracellular calcium concentration is an established function of Calmodulin which is known to interact with many GPCRs. Less is known about the functional role of the closely related neuronal EF-hand Ca2+-sensor proteins that frequently associate with calmodulin targets with different functional outcome. In the present study we aimed to investigate if a target of calmodulin – the A2A adenosine receptor, is able to associate with two other neuronal calcium binding proteins, namely NCS-1 and caldendrin. Using bioluminescence resonance energy transfer and co-immunoprecipitation experiments we show the existence of A2A - NCS-1 complexes in living cells whereas caldendrin did not associate with A2A receptors under the conditions tested. Interestingly, NCS-1 binding modulated downstream A2A receptor intracellular signalling in a Ca2+-dependent manner. Taken together this study provides further evidence that neuronal Ca2+-sensor proteins play an important role in modulation of GPCR signalling.

Fluorescent probe for turn-on sensing of L-cysteine by ensemble of AuNCs and polymer protected AuNPs.

Science.gov (United States)

Xu, Xiaozhe; Qiao, Juan; Li, Nan; Qi, Li; Zhang, Shufeng

2015-06-16

A new fluorescent probe based on ensemble of gold nanoclusters (AuNCs) and polymer protected gold nanoparticles (AuNPs) for turn-on sensing of L-cysteine was designed and prepared. The AuNCs were protected by bovine serum albumin and had strong fluorescence. The polymer protected AuNPs were synthesized by a facile in situ strategy at room temperature and could quench the fluorescence of AuNCs due to the Förster resonance energy transfer. Interestingly, it has been observed that the quenched fluorescence of AuNCs was recovered by L-cysteine, which could induce the aggregation of polymer protected AuNPs by sulfur group. Then the prepared fluorescent probe was successfully used for determination of L-Cys in human urines, which would have an evolving aspect and promote the subsequent exploration. Copyright © 2015 Elsevier B.V. All rights reserved.

Enhanced photocurrent in RuL2(NCS)2/di-(3-aminopropyl)-viologen/SnO2/ITO system

International Nuclear Information System (INIS)

Lee, Wonjoo; Kwak, Chang Gon; Mane, R.S.; Min, Sun Ki; Cai, Gangri; Ganesh, T.; Koo, Gumae; Chang, Jinho; Cho, Byung Won; Kim, Sei-Ki; Han, Sung-Hwan

2008-01-01

A Ru(2,2'-bipyridine-4,4'-dicarboxylic acid) 2 (NCS) 2 [RuL 2 (NCS) 2 ]/di-(3-aminopropyl)-viologen (DAPV)/tin oxide (SnO 2 ) system was prepared and applied to extensive photocurrent generation with its maximum surface area. The SnO 2 thin films on tin-doped indium oxide (ITO) were prepared using the chemical bath deposition method. Then, RuL 2 (NCS) 2 /DAPV on SnO 2 /ITO was easily prepared using self-assembled monolayers (SAMs). The photocurrent measurement of the system showed an excellent photocurrent of 20 nA cm -2 under the air mass 1.5 conditions (100 mW cm -2 ), which was increased by a factor of four compared to ones without SnO 2 layers

Rapid Detection of miRNA Using Nucleic Acids-templated AgNCs

DEFF Research Database (Denmark)

Shah, Pratik

. In the case of plants, the levels of certain miRNAs can be used as biomarkers to evaluate the physiological status. Specific miRNA levels are influenced by stresses such as drought, salt, cold, heat and pathogenic infestations. In humans, the dysregulation of miRNAs have been highlighted in many diseases...... such as cancer, diabetes, cardiovascular disease and Alzheimer’s disease. MiRNAs, thus, can be useful markers for disease diagnosis, prognosis, and treatment. Because of its attractive optical properties such as brightness, tuneable emission wavelengths and photo-stability, DNA stabilized silver nano......-clusters (AgNCs) has increasingly been used to create nanoscale bio-sensing systems for selective and specific detection of bio-molecules. During the course of my Ph.D., I have focused on developing a novel diagnostic tool for miRNA detection using the fluorescent properties of DNA encapsulated AgNCs (DNA...

Logistics worldwide for the whole nuclear cycle. Nuclear Cargo + Service GmbH

International Nuclear Information System (INIS)

Geiger, Horst; Schymke, Klaus

2011-01-01

Nuclear Cargo + Service GmbH (NCS) offers logistics worldwide for the whole nuclear cycle to fuel manufacturers, reactor operators, and waste management companies. Transport equipment and interim stores are part of the company's facilities. The firm's Front End unit conducts transnational transports of yellow cake, uranium hexafluoride, and enriched uranium and uranium from reprocessing. In the Back End unit, the company performs worldwide transports of spent fuel elements of research reactors. Another key area of activity is shipment of radioactive waste ranging from low-level waste to HAW (highly active waste generating heat). In its Component Disposal area, NCS offers a variety of transport services up to and including large components, e.g. reactor pressure vessels, both on the road and by rail and ship. NCS operates storage halls of its own for storing radioactive materials including radioactive waste. The technical equipment of NCS comprises a large pool of road and rail transport vehicles as well as a great number of vessels for radioactive materials. (orig.)

NCS-1 dependent learning bonus and behavior outputs of self-directed exploration

Science.gov (United States)

Mun, Ho-Suk

Animals explore a new environment and learn about their surroundings. "Exploration" refers to all activities that increase the information obtained from an animal. For this study, I determined a molecule that mediates self-directed exploration, with a particular focus on rearing behavior and vocalization. Rearing can be either self-directed exploration or escape-oriented exploration. Self-directed exploration can be driven by the desire to gather information about environments while escape-oriented exploration can be driven by fear or anxiety. To differentiate between these two concepts, I compared rearing and other behaviors in three different conditions 1) novel dim (safe environment), which induces exploration based rearing; 2) novel bright (fearful environment), which elicits fear driven rearing; and 3) familiar environment as a control. First, I characterized the effects on two distinct types of environment in exploratory behavior and its effect on learning. From this, I determined that self-directed exploration enhances spatial learning while escape-oriented exploration does not produce a learning bonus. Second, I found that NCS-1 is involved in exploration, as well as learning and memory, by testing mice with reduced levels of Ncs-1 by point mutation and also siRNA injection. Finally, I illustrated other behavior outputs and neural substrate activities, which co-occurred during either self-directed or escape-oriented exploration. I found that high-frequency ultrasonic vocalizations occurred during self-directed exploration while low-frequency calls were emitted during escape-oriented exploration. Also, with immediate early gene imaging techniques, I found hippocampus and nucleus accumbens activation in self-directed exploration. This study is the first comprehensive molecular analysis of learning bonus in self-directed exploration. These results may be beneficial for studying underlying mechanisms of neuropsychiatric disease, and also reveal therapeutic

Dosimetry study comparing NCS report-2 versus IAEA TRS-398 protocol for high energy photon beams

International Nuclear Information System (INIS)

Attalaa, E.M.; Khaled, N.E.; Abou Elenein, H.S.; Elsayed, A.A.

2005-01-01

In this work a dosimetry study is presented in which the results of absorbed dose determined at reference condition according to the IAEA TRS-398 protocol and the NCS report-2 are compared. The IAEA TRS-398 protocol for absorbed dose calibration is based on ionization chamber having absorbed dose to water calibration factor N d w, while the NCS-2 dosimetry report for absorbed dose calibration is based on an ionization chamber having air- kerma calibration factor N k . This study shows that the absorbed dose which is calculated with The IAEA TRS-398 formalisms is higher than that calculated with NCS report-2 formalisms within range from 0.4 to 0.9% in cobalt-60 beam as sensed by different ionization chambers, and from 0.2 to 1.1% for different higher energy photon beams of 6, 8 and 18 MV. The chambers used are PTW 30001, 30004, and NE-2571; which have calibration factors N k and N d w traceable to the BIPM (Bureau International des Poids et Mesures)

Modulation of the electroluminescence emission from ZnO/Si NCs/p-Si light-emitting devices via pulsed excitation

Science.gov (United States)

López-Vidrier, J.; Gutsch, S.; Blázquez, O.; Hiller, D.; Laube, J.; Kaur, R.; Hernández, S.; Garrido, B.; Zacharias, M.

2017-05-01

In this work, the electroluminescence (EL) emission of zinc oxide (ZnO)/Si nanocrystals (NCs)-based light-emitting devices was studied under pulsed electrical excitation. Both Si NCs and deep-level ZnO defects were found to contribute to the observed EL. Symmetric square voltage pulses (50-μs period) were found to notably enhance EL emission by about one order of magnitude. In addition, the control of the pulse parameters (accumulation and inversion times) was found to modify the emission lineshape, long inversion times (i.e., short accumulation times) suppressing ZnO defects contribution. The EL results were discussed in terms of the recombination dynamics taking place within the ZnO/Si NCs heterostructure, suggesting the excitation mechanism of the luminescent centers via a combination of electron impact, bipolar injection, and sequential carrier injection within their respective conduction regimes.

A theoretical study on the interstellar synthesis of H{sub 2}NCS{sup +} and HNCSH{sup +} cations

Energy Technology Data Exchange (ETDEWEB)

Gronowski, Marcin; Kołos, Robert, E-mail: marcingronowski@gmail.com, E-mail: rkolos@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, 44/52 Kasprzaka, 01-224 Warsaw (Poland)

2014-09-10

HNCS and NCSH molecules, recently discovered in the interstellar medium, are likely formed via the dissociative recombination of H{sub 2}NCS{sup +} or HNCSH{sup +} isomeric ions. Interstellar synthesis of the latter is discussed on theoretical grounds. The analysis of relevant potential energy surfaces suggests a key role for chemical processes in which CSH{sup +} or HCS{sup +} cations (most likely formed in CS+H{sub 3}{sup +} collisions) react with NH{sub 2} or NH{sub 3}. The astrochemical kinetic database (kida.uva.2011), appended with 7 sulfur-bearing molecules and 48 corresponding reactions, has been applied to model the evolution of HNCS, NCSH, and their cationic precursors in a quiescent molecular cloud. Based on the model and on spectroscopic predictions, for an object like TMC-1, we expect the total intensity of H{sub 2}NCS{sup +} microwave lines to be comparable to that observed for HSCN. Theoretically derived molecular parameters, of interest for radio spectroscopy, are given for the most stable cations sharing the H{sub 2}NCS{sup +} stoichiometry.

Crystal structure and spin state of mixed-crystals of iron with NCS and NCBH3 for the assembled complexes bridged by 1,3-bis(4-pyridyl)propanes

International Nuclear Information System (INIS)

Haruka Dote; Hiroki Yasuhara

2015-01-01

New mixed crystals, Fe(NCS) x (NCBH 3 )( 2-x )(bpp) 2 , (bpp = 1,3-bis(4-pyridyl)propane) were synthesized. The formation of mixed crystals was confirmed by powder X-ray diffraction patterns and single crystal X-ray structural analysis. Elemental analyses showed that all Fe(NCS) x (NCBH 3 )( 2-x )(bpp) 2 samples had more Fe(NCS) 2 unit than the preparation fraction. 57 Fe Moessbauer spectroscopy revealed that all the spectra consist of only Fe(NCS) 2 unit and Fe(NCBH 3 ) 2 unit. And the fraction of low-spin state in the Fe(NCBH 3 ) 2 unit changed with the change of x. The results suggested that the high spin site of Fe(NCS) 2 unit affects the spin state of Fe(NCBH 3 ) 2 unit. (author)

Heterogeneous Nature of Relaxation Dynamics of Room-Temperature Ionic Liquids (EMIm)₂[Co(NCS)₄] and (BMIm)₂[Co(NCS)₄

Energy Technology Data Exchange (ETDEWEB)

Hensel-Bielowka, Stella [Univ. of Silesia, Katowice (Poland). Inst. of Chemistry; Wojnarowska, Zaneta [Univ. of Silesia, Katowice (Poland). Inst. of Physics; Univ. of Silesia, Chorzow (Poland). Silesian Center for Education and Interdisciplinary Research (SMCEBI); Dzida, Marzena [Univ. of Silesia, Katowice (Poland). Inst. of Chemistry; Zorębski, Edward [Univ. of Silesia, Katowice (Poland). Inst. of Chemistry; Zorębski, Michał [Univ. of Silesia, Katowice (Poland). Inst. of Chemistry; Geppert-Rybczyńska, Monika [Univ. of Silesia, Katowice (Poland). Inst. of Chemistry; Peppel, Tim [Leibniz Inst. for Catalysis, Rostock (Germany); Grzybowska, Katarzyna [Univ. of Silesia, Katowice (Poland). Inst. of Physics; Wang, Yangyang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences; Sokolov, Alexei P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Chemical Sciences Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Paluch, Marian [Univ. of Silesia, Katowice (Poland). Inst. of Physics; Univ. of Silesia, Chorzow (Poland). Silesian Center for Education and Interdisciplinary Research (SMCEBI)

2015-08-11

Dynamic crossover above T_g has been recognized as a characteristic feature of molecular dynamics of liquids approaching glass transition. Experimentally, it is manifested as a change in Vogel–Fulcher–Tammann dependence or a breakdown of the Stokes–Einstein and related relations. In this study, we report the exception from this rather general pattern of behavior. By means of dielectric, ultrasonic, rheological, and calorimetric methods, dynamics of two good ionic conductors (BMIm)₂[Co(NCS)₄] and (EMIm)₂[Co(NCS)₄] of less common stoichiometry (2:1) was studied in a very broad temperature range. However, none of the mentioned dynamic changes was observed in the entire studied temperature range. On the contrary, the single VFT and the same fractional Walden coefficient were found for conductivity and viscosity changes over 12 decades. Finally and moreover, ultrasonic studies revealed that the data at temperatures which cover the normal liquid region cannot be fitted by a single exponential decay, and the Cole–Cole function should be used instead.

Electrochemiluminescence behavior of AgNCs and its application in immunosensors based on PANI/PPy-Ag dendrite-modified electrode.

Science.gov (United States)

Zhang, Lina; Wang, Yanhu; Shen, Lei; Yu, Jinghua; Ge, Shenguang; Yan, Mei

2017-07-10

In this study, hyperbranched polyethyleneimine-protected silver nanoclusters (hPEI-AgNCs) with excellent electrochemiluminescence (ECL) emission in the presence of coreactant K 2 S 2 O 8 were prepared by chemical reduction of silver ions (silver nitrate) coordinated with dendrigraft polymer, and successfully used for the construction of an ECL immunosensor. Polyaniline (PANI)/polypyrrole (PPy)-silver (Ag) dendrites with good electrical conductivity and biocompatibility were electropolymerized on the surface of indium tin oxide (ITO) electrode as carriers. Porous ZnO sphere-loaded hPEI-AgNCs-induced signal amplification strategies were integrated exquisitely and applied sufficiently. Taking carcinoembryonic antigen (CEA) as an example, under optimal conditions, the CEA concentration was determined to be in the range of 10 -3 ng mL -1 -100 ng mL -1 and with a detection limit of 0.4 pg mL -1 using this method; it exhibited excellent selectivity, high stability, and acceptable fabrication reproducibility. It was anticipated that hPEI-AgNCs would have promising applications in green, selective, and sensitive detection of target analytes in the future.

Design and characterization of metal-thiocyanate coordination polymers

OpenAIRE

Savard, Didier

2018-01-01

This thesis focuses on exploring the synthesis and chemical reactivity of thiocyanate-based building blocks of the type [M(SCN)x]y- for the synthesis of coordination polymers. A series of potassium, ammonium, and tetraalkylammonium metal isothiocyanate salts of the type Qy[M(SCN)x] were synthesized and structurally characterized. Most of the salts were revealed to be isostructural and classic Werner complexes, but for (Et4N)3[Fe(NCS)6] and (n-Bu4N)3[Fe(NCS)6], a solid-state size-dependent cha...

Design and manufacture NCS instruments for cement factories

International Nuclear Information System (INIS)

Nguyen Thanh Tuy; Nguyen Tien Dung; Dang Nguyet Anh; Nguyen Phuc; Khuong Thanh Tuan; Luong Duc Long; Pham Trong Quyen

2003-01-01

The ministry project 'Design and manufacture some of NCS instruments for cement factories' is a part of instrumentation for cement production in Vietnam. The objectives of the project include: 1/Design and manufacture the automatic control system for cement raw material mixing, connected to components X-ray analyzer through serial port of PC; 2/Design and manufacture the automatic discharge control system using gamma rays. The instruments, made by the project , for controlling the conveyor belt weighing machine can be easily improved for various types of conveyor belt weighing machines. Their mobility and software equipped can be adapted for requirement of modern cement production technology. The instruments are operating well in some cement factories and they are helping in quality control. (NHA)

The National Oceanic and Atmospheric Administration (NOAA) Climate Services Portal: A New Centralized Resource for Distributed Climate Information

Science.gov (United States)

Burroughs, J.; Baldwin, R.; Herring, D.; Lott, N.; Boyd, J.; Handel, S.; Niepold, F.; Shea, E.

2010-09-01

With the rapid rise in the development of Web technologies and climate services across NOAA, there has been an increasing need for greater collaboration regarding NOAA's online climate services. The drivers include the need to enhance NOAA's Web presence in response to customer requirements, emerging needs for improved decision-making capabilities across all sectors of society facing impacts from climate variability and change, and the importance of leveraging climate data and services to support research and public education. To address these needs, NOAA (during fiscal year 2009) embarked upon an ambitious program to develop a NOAA Climate Services Portal (NCS Portal). Four NOAA offices are leading the effort: 1) the NOAA Climate Program Office (CPO), 2) the National Ocean Service's Coastal Services Center (CSC), 3) the National Weather Service's Climate Prediction Center (CPC), and 4) the National Environmental Satellite, Data, and Information Service's (NESDIS) National Climatic Data Center (NCDC). Other offices and programs are also contributing in many ways to the effort. A prototype NCS Portal is being placed online for public access in January 2010, http://www.climate.gov. This website only scratches the surface of the many climate services across NOAA, but this effort, via direct user engagement, will gradually expand the scope and breadth of the NCS Portal to greatly enhance the accessibility and usefulness of NOAA's climate data and services.

Characterization of silver/polystyrene nanocomposites prepared by in situ bulk radical polymerization

Energy Technology Data Exchange (ETDEWEB)

Vukoje, Ivana D., E-mail: ivanav@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Vodnik, Vesna V., E-mail: vodves@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Džunuzović, Jasna V., E-mail: jasnav2002@googlemail.com [Institute of Chemistry, Technology and Metallurgy (ICTM)-Center of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade (Serbia); Džunuzović, Enis S., E-mail: edzunuzovic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Marinović-Cincović, Milena T., E-mail: milena@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia); Jeremić, Katarina, E-mail: kjeremic@tmf.bg.ac.rs [Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11120 Belgrade (Serbia); Nedeljković, Jovan M., E-mail: jovned@vinca.rs [Vinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade (Serbia)

2014-01-01

Graphical abstract: - Highlights: • Synthesis and characterization of polystyrene nanocomposites based on Ag nanoparticles. • The glass transition temperature decreased in nanocomposites with respect to the pure polymer. • Resistance of the polymer to thermal degradation enhanced with Ag nanoparticles content. - Abstract: Nanocomposites (NCs) with different content of silver nanoparticles (Ag NPs) embeded in polystyrene (PS) matrix were prepared by in situ bulk radical polymerization. The nearly monodisperse Ag NPs protected with oleylamine were synthesized via organic solvo-thermal method and further used as a filler. The as-prepared spherical Ag NPs with diameter of 7.0 ± 1.5 nm were well dispersed in the PS matrix. The structural properties of the resulting Ag/PS NCs were characterized by transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy, while optical properties were characterized using optical absorption measurements. The gel permeation chromatography (GPC) measurements showed that the presence of Ag NPs stabilized with oleylamine has no influence on the molecular weight and polydispersity of the PS matrix. The influence of silver content on the thermal properties of Ag/PS NCs was investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results indicated that resistance of PS to thermal degradation was improved upon incorporation of Ag NPs. The Ag/PS NCs have lower glass transition temperatures than neat PS because loosely packed oleylamine molecules at the interface caused the increase of free volume and chain segments mobility near the surface of Ag NPs.

Degradation chemistry of RuLL´(NCS)2 complexes in the Dye-sensitized solar cell

DEFF Research Database (Denmark)

Lund, Torben

will present and overview of our degradation investigations of the ruthenium dyes N719, Z907 and C106 with the general structure RuLL´(NCS)2 and show how detailed degradation mechanistic knowledge is important in the developing of DSC cells with improved thermal dye stability. The various ruthenium dye...

Synthesis and characterization of some metal oxide nanocrystals by microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Rashad, M.; Gaber, A.; Abdelrahim, M. A.; Abdel-Baset, A. M. [Physics Department, Faculty of Science, Assiut University, 71516 Assiut (Egypt); Moharram, A. H. [Physics Dept., College of Science and Arts, King Abdulaziz Univ., Rabigh 21911 (Saudi Arabia)

2013-12-16

Copper oxide and cobalt oxide (CuO, Co3O4) nanocrystals (NCs) have been successfully prepared in a short time using microwave irradiation. The resulted powders of nanocrystals (NCs) were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) measurements are also studied. Fourier-transform infrared (FT-IR) and UV–visible absorption spectroscopy of both kind of nanoparticels are illustrated. Optical absorption analysis indicated the direct band gap for both kinds of nanocrystals.

Reversible and Topotactic Solvent Removal in a Magnetic Ni(NCS)2 Coordination Polymer.

Science.gov (United States)

Suckert, Stefan; Rams, Michał; Rams, Marek M; Näther, Christian

2017-07-17

Reaction of Ni(NCS) 2 with 4-(Boc-amino)pyridine in acetonitrile leads to the formation of a new coordination polymer with the composition Ni(NCS) 2 (4-(Boc-amino)pyridine) 2 ·MeCN (1-MeCN). In the crystal structure the Ni(II) cations are linked by the anionic ligands into chains that are further connected into layers by intermolecular N-H···O hydrogen bonding. These layers are stacked and channels are formed, in which acetonitrile molecules are located. Solvent removal leads to the ansolvate 1, which shows microporosity as proven by sorption measurements. Single crystal X-ray investigations reveal that the solvent removal leads to a change in symmetry from primitive to C-centered, which is reversible and which proceeds via a topotactic reaction leaving the network intact. The magnetic properties of 1-MeCN and 1 are governed by the ferromagnetic exchange between spins of Ni(II) forming chains. The susceptibility and specific heat for such a quantum Heisenberg chain of S = 1 spins with zero-field splitting are calculated using the DMRG method and compared with the experimental results.

Contrast between the mechanisms for dissociative electron attachment to CH3SCN and CH3NCS

Science.gov (United States)

Miller, Thomas M.; Viggiano, Albert A.; Shuman, Nicholas S.

2018-05-01

The kinetics of thermal electron attachment to methyl thiocyanate (CH3SCN), methyl isothiocyanate (CH3NCS), and ethyl thiocyanate (C2H5SCN) were measured using flowing afterglow-Langmuir probe apparatuses at temperatures between 300 and 1000 K. CH3SCN and C2H5SCN undergo inefficient dissociative attachment to yield primarily SCN- at 300 K (k = 2 × 10-10 cm3 s-1), with increasing efficiency as temperature increases. The increase is well described by activation energies of 0.17 eV (CH3SCN) and 0.14 eV (C2H5SCN). CN- product is formed at product but at a rate at 300 K that is below our detection threshold (k differentiating the two mechanisms. The kinetic modeling reproduces the CH3NCS data only if dissociation through the transient anion is considered.

Spectra and relaxation dynamics of the pseudohalide (PS) vibrational bands for Ru(bpy)2(PS)2 complexes, PS = CN, NCS and N3

International Nuclear Information System (INIS)

Compton, Ryan; Gerardi, Helen K.; Weidinger, Daniel; Brown, Douglas J.; Dressick, Walter J.; Heilweil, Edwin J.; Owrutsky, Jeffrey C.

2013-01-01

Highlights: ► Static and transient infrared spectroscopy of pseudohalide bipyridine ruthenium complexes. ► Vibrational energy relaxes faster for the azide than the thiocyanate and cyanide analogs. ► Intramolecular vibrational relaxation is prevalent in cis-Ru(bpy) 2 (N 3 ) 2 . - Abstract: Static and transient infrared spectroscopy were used to investigate cis-Ru(bpy) 2 (N 3 ) 2 (bpy = 2,2′-bipyridine), cis-Ru(bpy) 2 (NCS) 2 , and cis-Ru(bpy) 2 (CN) 2 in solution. The NC stretching IR band for cis-Ru(bpy) 2 (NCS) 2 appears at higher frequency (∼2106 cm −1 in DMSO) than for the free NCS − anion while the IR bands for the azide and cyanide complexes are closer to those of the respective free anions. The vibrational energy relaxation (VER) lifetime for the azide complex is found to be much shorter (∼5 ps) than for either the NCS or CN species (both ∼70 ps in DMSO) and the lifetimes resemble those for each corresponding free anion in solution. However, for cis-Ru(bpy) 2 (N 3 ) 2 , it is determined that the transition frequency depends more on the solvent than the VER lifetime implying that intramolecular vibrational relaxation is predominant over solvent energy-extracting interactions. These results are compared to the behavior of other related metal complexes in solution

Crystal structure and spin state of mixed-crystals of Fe(NCS)x(NCBH3)2-x(bpp)2 (bpp = 1,3-BIS(4-pyridyl)propane)

International Nuclear Information System (INIS)

Dote, Haruka; Yasuhara, Hiroki; Nakashima, Satoru

2013-01-01

New mixed crystals, Fe(NCS) x (NCBH 3 ) (2-x) (bpp) 2 were synthesized. 57 Fe Mössbauer spectroscopy showed that the ratio of low-spin state in the Fe(NCBH 3 ) 2 unit changed with the change of x. The results revealed that the high spin site of Fe(NCS) 2 unit affects the spin state of Fe(NCBH 3 ) 2 unit. (author)

Computational molecular spectroscopy of X ˜ 2 Π NCS: Electronic properties and ro-vibrationally averaged structure

Science.gov (United States)

Hirano, Tsuneo; Nagashima, Umpei; Jensen, Per

2018-04-01

For NCS in the X ˜ 2 Π electronic ground state, three-dimensional potential energy surfaces (3D PESs) have been calculated ab initio at the core-valence, full-valence MR-SDCI+Q/[aug-cc-pCVQZ (N, C, S)] level of theory. The ab initio 3D PESs are employed in second-order-perturbation-theory and DVR3D calculations to obtain various molecular constants and ro-vibrationally averaged structures. The 3D PESs show that the X ˜ 2 Π NCS has its potential minimum at a linear configuration, and hence it is a "linear molecule." The equilibrium structure has re (N-C) = 1.1778 Å, re (C-S) = 1.6335 Å, and ∠e (N-C-S) = 180°. The ro-vibrationally averaged structure, determined as expectation values over DVR3D wavefunctions, has 〈 r (N-C)〉0 = 1.1836 Å, 〈 r (C-S)〉0 = 1.6356 Å, and 〈 ∠ (N-C-S)〉0 = 172.5°. Using these expectation values as the initial guess, a bent r0 structure having an 〈 ∠ (N-C-S)〉0 of 172.2° is deduced from the experimentally reported B0 values for NC32S and NC34S. Our previous prediction that a linear molecule, in any ro-vibrational state including the ro-vibrational ground state, is to be "observed" as being bent on ro-vibrational average, has been confirmed here theoretically through the expectation value for the bond-angle deviation from linearity, 〈 ρ bar 〉 , and experimentally through the interpretation of the experimentally derived rotational-constant values.

Solid state luminescence of CuI and CuNCS complexes with phenanthrolines and a new tris (aminomethyl) phosphine derived from N-methyl-2-phenylethanamine

International Nuclear Information System (INIS)

Starosta, Radosław; Komarnicka, Urszula K.; Puchalska, Małgorzata

2014-01-01

A new tris (aminomethyl) phosphine derived from N-methyl-2-phenylethanamine P(CH 2 N(CH 3 )CH 2 CH 2 Ph) 3 (1) has been synthesized and characterized by the NMR spectra. Also, three new copper(I) iodide or isothiocyanate complexes with 1 1,10-phenanthroline (phen) and 2,9-dimethyl-1,10-phenanthroline (dmp) [CuI(phen)P(CH 2 N(CH 3 )CH 2 CH 2 Ph) 3 ] (1P) CuI(dmp)P(CH 2 N(CH 3 )CH 2 CH 2 Ph) 3 ] (1I) and [CuNCS(dmp)P(CH 2 N(CH 3 )CH 2 CH 2 Ph) 3 ] (1T), have been synthesized and characterized by elemental analysis as well as studied by NMR, UV–vis, IR and luminescence spectroscopies. An X-ray structure of 1P complex revealed that the geometry around Cu(I) center in this complex is distorted pseudo-tetrahedral. Investigated complexes exhibit orange, rather weak photoluminescence in the solid state. This relatively low intensity may be related to the high flattening deformations of the molecular geometries in the excited triplet states On the basis of TDDFT calculations we confirmed that the absorbance and luminescence bands of (MX,MPR 3 )LCT as well as of (MX)LCT types result mainly from the transitions from the copper–iodine (or isothiocyanate) bonds and a small admixture of copper–phosphine bonds to antibonding orbitals of phen or dmp diimines. -- Highlights: • A novel tris(aminomethyl)phosphine is obtained from N-methyl-2-phenylethanamine. • Three new CuI and CuNCS complexes with phen or dmp and a novel phosphine are presented. • The obtained complexes are luminescent in the solid state. • Main absorbance and luminescence bands are of (MX,MPR 3 )LCT as well as (MX)LCT types

Comparison of the octadentate bifunctional chelator DFO*-pPhe-NCS and the clinically used hexadentate bifunctional chelator DFO-pPhe-NCS for {sup 89}Zr-immuno-PET

Energy Technology Data Exchange (ETDEWEB)

Vugts, Danielle J.; Klaver, Chris; Sewing, Claudia; Poot, Alex J.; Adamzek, Kevin; Visser, Gerard W.M.; Dongen, Guus A.M.S. van [VU University Medical Center, Department of Radiology and Nuclear Medicine, Amsterdam (Netherlands); Huegli, Seraina; Mari, Cristina; Gasser, Gilles [University of Zurich, Department of Chemistry, Zurich (Switzerland); Valverde, Ibai E. [University of Basel Hospital, Division of Radiopharmaceutical Chemistry, Basel (Switzerland); Mindt, Thomas L. [Institute of Pharmaceutical Sciences, ETH Zurich, Zurich (Switzerland); General Hospital of Vienna, Ludwig Boltzmann Institute for Applied Diagnostics, Vienna (Austria)

2017-02-15

All clinical {sup 89}Zr-immuno-PET studies are currently performed with the chelator desferrioxamine (DFO). This chelator provides hexadentate coordination to zirconium, leaving two coordination sites available for coordination with, e.g., water molecules, which are relatively labile ligands. The unsaturated coordination of DFO to zirconium has been suggested to result in impaired stability of the complex in vivo and consequently in unwanted bone uptake of {sup 89}Zr. Aiming at clinical improvements, we report here on a bifunctional isothiocyanate variant of the octadentate chelator DFO* and the in vitro and in vivo comparison of its {sup 89}Zr-DFO*-mAb complex with {sup 89}Zr-DFO-mAb. The bifunctional chelator DFO*-pPhe-NCS was prepared from previously reported DFO* and p-phenylenediisothiocyanate. Subsequently, trastuzumab was conjugated with either DFO*-pPhe-NCS or commercial DFO-pPhe-NCS and radiolabeled with Zr-89 according to published procedures. In vitro stability experiments were carried out in saline, a histidine/sucrose buffer, and blood serum. The in vivo performance of the chelators was compared in N87 tumor-bearing mice by biodistribution studies and PET imaging. In 0.9 % NaCl {sup 89}Zr-DFO*-trastuzumab was more stable than {sup 89}Zr-DFO-trastuzumab; after 72 h incubation at 2-8 C 95 % and 58 % intact tracer were left, respectively, while in a histidine-sucrose buffer no difference was observed, both products were ≥ 92 % intact. In vivo uptake at 144 h post injection (p.i.) in tumors, blood, and most normal organs was similar for both conjugates, except for skin, liver, spleen, ileum, and bone. Tumor uptake was 32.59 ± 11.95 and 29.06 ± 8.66 % ID/g for {sup 89}Zr-DFO*-trastuzumab and {sup 89}Zr-DFO-trastuzumab, respectively. The bone uptake was significantly lower for {sup 89}Zr-DFO*-trastuzumab compared to {sup 89}Zr-DFO-trastuzumab. At 144 h p.i. for {sup 89}Zr-DFO*-trastuzumab and {sup 89}Zr-DFO-trastuzumab, the uptake in sternum was 0.92 �

Effect of polarizable lone pair cations on the second-harmonic generation (SHG) properties of noncentrosymmetric (NCS) Bi(2-x)Y(x)TeO₅ (x = 0-0.2).

Science.gov (United States)

Jo, Hongil; Kim, Yeong Hun; Lee, Dong Woo; Ok, Kang Min

2014-08-14

Y(3+)-doped noncentrosymmetric (NCS) bismuth tellurite materials, Bi(2-x)Y(x)TeO5 (x = 0, 0.1, and 0.2), have been synthesized through standard solid-state reactions and structurally characterized by powder neutron diffraction. The reported NCS materials crystallize in the orthorhombic space group Abm2 (no. 39), and exhibit pseudo-three-dimensional frameworks that are composed of BiO3, BiO5, and TeO3 polyhedra. Detailed diffraction studies show that the cell volume of Bi(2-x)Y(x)TeO5 decreases with an increasing amount of Y(3+)on the Bi(3+) sites. However, no ordering between Bi(3+) and Y(3+) was observed in the Bi(2-x)Y(x)TeO5. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that Bi2TeO5, Bi(1.9)Y(0.1)TeO5, and Bi(1.8)Y(0.2)TeO5 exhibit SHG efficiencies of approximately 300, 200, and 60 times that of α-SiO2, respectively. The reduction in SHG for Y(3+)-doped materials is consistent with the lack of net moment originating from polyhedra with a polarizable Bi(3+) cation.

Magnetically separable Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposites: Preparation, characterization and visible-light photocatalytic performance

Energy Technology Data Exchange (ETDEWEB)

Cao, Chunhua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@whu.edu.cn [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Cao, Qihua [School of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China)

2015-04-01

Highlights: • A novel magnetically-separable Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} photocatalyst was in situ prepared. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs had rough and porous chitosan surface layer embedded with Fe{sub 3}O{sub 4} NPs. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed large surface areas and special dimodal pore structure. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs showed superparamagnetism and could be easily magnetic separated. • Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited good visible-light photocatalytic activity and stability. - Abstract: A novel magnetically-separable visible-light-induced photocatalyst, Cu{sub 2}O/chitosan–Fe{sub 3}O{sub 4} nanocomposite (Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NC), was prepared via a facile one-step precipitation–reduction process by using magnetic chitosan chelating copper ions as precursor. The structure and properties of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs were characterized by XRD, FT-IR, SEM, HRTEM, SAED, EDS, BET, VSM, XPS and UV–vis/DRS. The photocatalytic activity of Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs was evaluated by decolorization of reactive brilliant red X-3B (X-3B) under visible light irradiation. The characterization results indicated that Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs exhibited relatively large specific surface areas and special dimodal pore structure because Cu{sub 2}O was wrapped in chitosan matrix embedded with Fe{sub 3}O{sub 4} nanoparticles. The tight combination of magnetic Fe{sub 3}O{sub 4} and semiconductor Cu{sub 2}O through chitosan made the nanocomposites show good superparamagnetism and photocatalytic activity. It was found that X-3B could be decolorized more efficiently in acidic media than in neutral or alkaline media. The decolorization of X-3B was ascribed to the synergistic effect of photocatalysis and adsorption. Cu{sub 2}O/CS–Fe{sub 3}O{sub 4} NCs could be easily separated from the solution by an external magnet, and the decolorization rates of X-3B

Application of Network Analysis for Characterizing Service Modularity

DEFF Research Database (Denmark)

Frandsen, Thomas

2012-01-01

The purpose of this paper is to explore the potential of the application of network analytical techniques to identify and characterize modularity of service processes. Services can be conceptualized as systems of interrelated components which can be decomposed in order to achieve a modular design...

Photo-Induced Spin State Switching In [Fe(bpp)2](NCS)2·2H2O

International Nuclear Information System (INIS)

Bhattacharjee, Ashis; Goodwin, Harry A.; Guetlich, Philipp

2010-01-01

We present the results of our investigation into the effect of irradiation of green light on the high spin low spin transition behavior of the mononuclear iron(II) compound [Fe(bpp) 2 ](NCS) 2 ·2H 2 O explored with the help of magnetic as well as Moessbauer spectroscopic studies. It has been found that the compound exhibits molecular bistability under irradiation of light due to LIESST effect.

Spectra and relaxation dynamics of the pseudohalide (PS) vibrational bands for Ru(bpy){sub 2}(PS){sub 2} complexes, PS = CN, NCS and N{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Compton, Ryan; Gerardi, Helen K. [Chemistry Division, Naval Research Laboratory, Washington, DC 20375 (United States); Weidinger, Daniel [SRA International, 4300 Fair Lakes Court, Fairfax, VA 22033 (United States); Brown, Douglas J. [Chemistry Department, US Naval Academy, Annapolis, MD 21402 (United States); Dressick, Walter J. [Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, DC 20375 (United States); Heilweil, Edwin J. [Radiation and Biomolecular Physics Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Owrutsky, Jeffrey C., E-mail: Jeff.Owrutsky@nrl.navy.mil [Chemistry Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2013-08-30

Highlights: ► Static and transient infrared spectroscopy of pseudohalide bipyridine ruthenium complexes. ► Vibrational energy relaxes faster for the azide than the thiocyanate and cyanide analogs. ► Intramolecular vibrational relaxation is prevalent in cis-Ru(bpy){sub 2}(N{sub 3}){sub 2}. - Abstract: Static and transient infrared spectroscopy were used to investigate cis-Ru(bpy){sub 2}(N{sub 3}){sub 2} (bpy = 2,2′-bipyridine), cis-Ru(bpy){sub 2}(NCS){sub 2}, and cis-Ru(bpy){sub 2}(CN){sub 2} in solution. The NC stretching IR band for cis-Ru(bpy){sub 2}(NCS){sub 2} appears at higher frequency (∼2106 cm{sup −1} in DMSO) than for the free NCS{sup −} anion while the IR bands for the azide and cyanide complexes are closer to those of the respective free anions. The vibrational energy relaxation (VER) lifetime for the azide complex is found to be much shorter (∼5 ps) than for either the NCS or CN species (both ∼70 ps in DMSO) and the lifetimes resemble those for each corresponding free anion in solution. However, for cis-Ru(bpy){sub 2}(N{sub 3}){sub 2}, it is determined that the transition frequency depends more on the solvent than the VER lifetime implying that intramolecular vibrational relaxation is predominant over solvent energy-extracting interactions. These results are compared to the behavior of other related metal complexes in solution.

Characterization of Semiconductor Nanocrystal Assemblies as Components of Optoelectronic Devices

Science.gov (United States)

Malfavon-Ochoa, Mario

This dissertation presents new insight into the ability of small molecule passivated NCs to achieve intimate approach distances, despite being well passivated, while developing guiding principles in the area of ligand mediated microstructure control and the resulting macroscopic optical and electronic properties that close packing of high quality NCs enables. NC ligand coverage will be characterized quantitatively through thermogravimetric analysis (TGA), and qualitatively by photoluminescence and electroluminescence, in the case of functional devices; illustrating the importance of practitioner dependent control of ligand coverage through variations in the dispersion precipitation purification procedure. A unique examination of the relative contribution of energy and charge transfer in NC LEDs will demonstrate the ability to achieve charge transfer, at a level competitive with energy transfer, to well passivated NCs at various wt% loading in a polymer matrix. The observation of potential dependent recombination zones within an active layer further suggest novel, NC surface passivation mediated control of blend microstructure during solution processing towards the development of a bi-continuous network. Next, NC self-assembly and resulting microstructure dependent optical and electronic properties will be examined through electroluminescence and high-resolution transmission electron microscopy (TEM) micrographs of functional NC/polymer bulk heterojunction LEDs. The joint characterization of NC optical properties, and self-assembly microstructure provide a deeper understanding of the significant and inseparable effects of minimal changes in NC surface passivation on structure and function, and emphasize the potential to rely on strongly passivating ligands to control physical properties and processing parameters concurrently towards higher efficiency devices via low cost processing. Finally, micro-contact printing of blazed transmission gratings, using stable

CuO and Co3O4 Nanoparticles: Synthesis, Characterizations, and Raman Spectroscopy

Directory of Open Access Journals (Sweden)

M. Rashad

2013-01-01

Full Text Available Copper oxide and cobalt oxide (CuO, Co3O4 nanocrystals (NCs have been successfully prepared in a short time using microwave irradiation without any postannealing treatment. Both kinds of nanocrystals (NCs have been prepared using copper nitrate and cobalt nitrate as the starting materials and distilled water as the solvent. The resulted powders of nanocrystals (NCs were characterized by X-ray diffraction (XRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, and atomic force microscopy (AFM measurements. The obtained results confirm the presence of the both of oxides nanopowders produced during chemical precipitation using microwave irradiation. A strong emission under UV excitation is obtained from the prepared CuO and Co3O4 nanoparticles. The results show that the nanoparticles have high dispersion and narrow size distribution. The line scans of atomic force microscopy (AFM images of the nanocrystals (NCs sprayed on GaAs substrates confirm the results of both X-ray diffraction and transmission electron microscopy. Furthermore, vibrational studies have been carried out using Raman spectroscopic technique. Specific Raman peaks have been observed in the CuO and Co3O4 nanostructures, and the full width at half maximum (FWHM of the peaks indicates a small particle size of the nanocrystals.

Exploiting structure similarity in refinement: automated NCS and target-structure restraints in BUSTER

Energy Technology Data Exchange (ETDEWEB)

Smart, Oliver S., E-mail: osmart@globalphasing.com; Womack, Thomas O.; Flensburg, Claus; Keller, Peter; Paciorek, Włodek; Sharff, Andrew; Vonrhein, Clemens; Bricogne, Gérard [Global Phasing Ltd, Sheraton House, Castle Park, Cambridge CB3 0AX (United Kingdom)

2012-04-01

Local structural similarity restraints (LSSR) provide a novel method for exploiting NCS or structural similarity to an external target structure. Two examples are given where BUSTER re-refinement of PDB entries with LSSR produces marked improvements, enabling further structural features to be modelled. Maximum-likelihood X-ray macromolecular structure refinement in BUSTER has been extended with restraints facilitating the exploitation of structural similarity. The similarity can be between two or more chains within the structure being refined, thus favouring NCS, or to a distinct ‘target’ structure that remains fixed during refinement. The local structural similarity restraints (LSSR) approach considers all distances less than 5.5 Å between pairs of atoms in the chain to be restrained. For each, the difference from the distance between the corresponding atoms in the related chain is found. LSSR applies a restraint penalty on each difference. A functional form that reaches a plateau for large differences is used to avoid the restraints distorting parts of the structure that are not similar. Because LSSR are local, there is no need to separate out domains. Some restraint pruning is still necessary, but this has been automated. LSSR have been available to academic users of BUSTER since 2009 with the easy-to-use -autoncs and @@target target.pdb options. The use of LSSR is illustrated in the re-refinement of PDB entries http://scripts.iucr.org/cgi-bin/cr.cgi?rm, where -target enables the correct ligand-binding structure to be found, and http://scripts.iucr.org/cgi-bin/cr.cgi?rm, where -autoncs contributes to the location of an additional copy of the cyclic peptide ligand.

Lifetime Prevalence of Mental Disorders in U.S. Adolescents: Results from the National Comorbidity Survey Replication-Adolescent Supplement (NCS-A)

Science.gov (United States)

Merikangas, Kathleen Ries; He, Jian-ping; Burstein, Marcy; Swanson, Sonja A.; Avenevoli, Shelli; Cui, Lihong; Benjet, Corina; Georgiades, Katholiki; Swendsen, Joel

2010-01-01

Objective: To present estimates of the lifetime prevalence of "DSM-IV" mental disorders with and without severe impairment, their comorbidity across broad classes of disorder, and their sociodemographic correlates. Method: The National Comorbidity Survey-Adolescent Supplement NCS-A is a nationally representative face-to-face survey of…

Advances of NOAA Training Program in Climate Services

Science.gov (United States)

Timofeyeva, M. M.

2012-12-01

Since 2002, NOAA's National Weather Service (NWS) Climate Services Division (CSD) has offered numerous training opportunities to NWS staff. After eight-years of development, the training program offers three instructor-led courses and roughly 25 online (distance learning) modules covering various climate topics, such as: climate data and observations, climate variability and change, and NWS national / local climate products (tools, skill, and interpretation). Leveraging climate information and expertise available at all NOAA line offices and partners allows for the delivery of the most advanced knowledge and is a very critical aspect of the training program. The emerging NOAA Climate Service (NCS) requires a well-trained, climate-literate workforce at the local level capable of delivering NOAA's climate products and services as well as providing climate-sensitive decision support. NWS Weather Forecast Offices and River Forecast Centers presently serve as local outlets for the NCS climate services. Trained NWS climate service personnel use proactive and reactive approaches and professional education methods in communicating climate variability and change information to local users. Both scientifically-sound messages and amiable communication techniques are important in developing an engaged dialog between the climate service providers and users. Several pilot projects have been conducted by the NWS CSD this past year that apply the program's training lessons and expertise to specialized external user group training. The technical user groups included natural resources managers, engineers, hydrologists, and planners for transportation infrastructure. Training of professional user groups required tailoring instructions to the potential applications for each group of users. Training technical users identified the following critical issues: (1) knowledge of target audience expectations, initial knowledge status, and potential use of climate information; (2) leveraging

Synthesis, structural and electrical properties of [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Karoui, Sahel [Laboratoire genie de materiaux et environnement, ENIS, BP.1173,3038- Sfax, Universite de Sfax (Tunisia); Kamoun, Slaheddine, E-mail: slah.kamoun@gmail.com [Laboratoire genie de materiaux et environnement, ENIS, BP.1173,3038- Sfax, Universite de Sfax (Tunisia); Jouini, Amor [Laboratoire de Chimie du Solide, Departement de Chimie, Faculte des Sciences de Monastir, 5019 Monastir (Tunisia)

2013-01-15

Synthesis, structural and electrical properties are given for a new organic stannous pseudo halide material. The structure of the [C{sub 2}H{sub 10}N{sub 2}][(SnCl(NCS){sub 2}]{sub 2} reveals that the adjacent Sn(II) centres are bridged by a pair of SCN{sup -} anions to form a 1-D array giving rise to the anionic chains (SnCl(NCS){sub 2}){sub n}{sup n-}. These chains are themselves interconnected by means of N-H Horizontal-Ellipsis Cl(S) hydrogen bonds originating from the organic cation [(NH{sub 3}){sub 2}(CH{sub 2}){sub 2}]{sup 2+}. The AC impedance measurements were performed as a function of both frequency and temperature. The electrical conduction and dielectric relaxation have been studied. The activation energy associated with the electrical relaxation determined from the electric modulus spectra was found close to that of the activation energy obtained for DC conductivity. The conduction mechanisms are attributed to the quantum mechanical tunneling model in phase I and to the proton hopping among hydrogen vacancies in phase II. - Graphical abstract: Atomic coordination in [C2H10N2][SnCl(NCS)2)2]. Highlights: Black-Right-Pointing-Pointer X-ray diffraction analysis shows the 1D network character of the structure. Black-Right-Pointing-Pointer DSC experiments show a phase transition at 336 K. Black-Right-Pointing-Pointer The AC conductivity is interpreted in terms of Jonsher's law. Black-Right-Pointing-Pointer Two conduction mechanisms are proposed for phase I and II.

Current status and trends of cooperation on radiotracer and NCS technologies

Energy Technology Data Exchange (ETDEWEB)

Thereska, J. [International Atomic Energy Agency, Vienna (Austria). Industrial Applications and Chemistry Section

1997-10-01

Relevant target areas for radiotracer and neutronic control system (NCS) applications are defined. The petroleum and petrochemical industries, mineral processing and waste-water treatment sectors are identified as the most appropriate beneficiaries. The new CRP on `Radiotracer technology for engineering unit operations studies and unit process optimisation` aims to improve the radiotracer methodology, including new radiotracers, development of expert systems, new software for data processing with finite element techniques for flow structure visualisation, as well as to formulate guidelines for problem solving of complex processes. The organisation of a CRP on `Multibeam radiogauging for multi-phase systems studies` to further develop and refine nucleonic gauge methodology and technology, including development of expert systems for optimal design and calibration, quality control according to ISO standards, emerging new applications, and formulation of guidelines and software for on line measurement of multi-phase system parameters of complex processes will be discussed in the near future

Current status and trends of cooperation on radiotracer and NCS technologies

International Nuclear Information System (INIS)

Thereska, J.

1997-01-01

Relevant target areas for radiotracer and neutronic control system (NCS) applications are defined. The petroleum and petrochemical industries, mineral processing and waste-water treatment sectors are identified as the most appropriate beneficiaries. The new CRP on 'Radiotracer technology for engineering unit operations studies and unit process optimisation' aims to improve the radiotracer methodology, including new radiotracers, development of expert systems, new software for data processing with finite element techniques for flow structure visualisation, as well as to formulate guidelines for problem solving of complex processes. The organisation of a CRP on 'Multibeam radiogauging for multi-phase systems studies' to further develop and refine nucleonic gauge methodology and technology, including development of expert systems for optimal design and calibration, quality control according to ISO standards, emerging new applications, and formulation of guidelines and software for on line measurement of multi-phase system parameters of complex processes will be discussed in the near future

Cav1.3 channels control D2-autoreceptor responses via NCS-1 in substantia nigra dopamine neurons

Science.gov (United States)

Dragicevic, Elena; Poetschke, Christina; Duda, Johanna; Schlaudraff, Falk; Lammel, Stephan; Schiemann, Julia; Fauler, Michael; Hetzel, Andrea; Watanabe, Masahiko; Lujan, Rafael; Malenka, Robert C.; Striessnig, Joerg

2014-01-01

and genetic tools, we identified that the expression of this sensitized D2-autoreceptor phenotype required Cav1.3 L-type Ca2+ channel activity, internal Ca2+, and the interaction of the neuronal calcium sensor NCS-1 with D2-autoreceptors. Thus, we identified a first physiological function of Cav1.3 L-type Ca2+ channels in SN DA neurons for homeostatic modulation of their D2-autoreceptor responses. L-type Ca2+ channel activity however, was not important for pacemaker activity of mouse SN DA neurons. Furthermore, we detected elevated substantia nigra dopamine messenger RNA levels of NCS-1 (but not Cav1.2 or Cav1.3) after cocaine in mice, as well as in remaining human SN DA neurons in Parkinson’s disease. Thus, our findings provide a novel homeostatic functional link in SN DA neurons between Cav1.3- L-type-Ca2+ channels and D2-autoreceptor activity, controlled by NCS-1, and indicate that this adaptive signalling network (Cav1.3/NCS-1/D2/GIRK2) is also active in human SN DA neurons, and contributes to Parkinson’s disease pathology. As it is accessible to pharmacological modulation, it provides a novel promising target for tuning substantia nigra dopamine neuron activity, and their vulnerability to degeneration. PMID:24934288

In vitro cytotoxicity evaluation of nano-carbon particles with different sp{sup 2}/sp{sup 3} ratios

Energy Technology Data Exchange (ETDEWEB)

Li, S.S.; Wu, B.J.; Deng, Q.Y. [Key Laboratory for Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Guo, Y.B. [The Third People' s Hospital of Chengdu, Sichuan 610031 (China); Leng, Y.X., E-mail: yxleng@263.net [Key Laboratory for Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Huang, N. [Key Laboratory for Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)

2017-06-01

Graphitization occurs during the long-term service of a diamond-like carbon (DLC) modified artificial joint. Then, DLC wear debris, which are carbon particles with different sp{sup 2}/sp{sup 3} ratios and sizes ranging from the nano- to micro-meter scale produced. In this paper, to promote the application of DLC coating for artificial joint modification, the cytotoxicity of DLC debris (nano-carbon particles, NCs) with different sp{sup 2}/sp{sup 3} ratios was studied. The microstructure and physical characteristics of NCs with different sp{sup 2}/sp{sup 3} ratios were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Transmission Electron Microscope (TEM) and Dynamic Light Scattering (DLS). Meanwhile, osteoblasts and macrophages were applied to characterize the cytotoxicity of the NCs. In vitro cytotoxicity assay results indicated that cells incubated with NCs of different sp{sup 2}/sp{sup 3} ratios had greater osteogenic capacity, and these particles caused a weaker immune response in comparison with CoCrMo particles. Taken together, the results indicated that NCs with different sp{sup 2}/sp{sup 3} ratios presented a good cytocompatibility than CoCrMo particles. But no significant differences were observed among NCs with different sp{sup 2}/sp{sup 3} ratios. The better cytocompatibility of NCs is mainly attributable to their surface charge. - Highlights: • NCs with different sp{sup 2}/sp{sup 3} ratios have been successfully prepared by annealing treatment. • NCs with different sp{sup 2}/sp{sup 3} ratios show good osteogenic capacity and lower immune response. • The good cytocompatibility of NCs is mainly dependent on its surface charge.

Isotope effect study of κ-(BEDT-TTF)2Cu(NCS)2: Labeling in the anion

International Nuclear Information System (INIS)

Kini, A.M.; Wang, H.H.; Schlueter, J.A.

1995-01-01

Since the initial discovery of organic superconductivity in 1979, a large number of organic superconductors have now been synthesized. However, the mechanism of electron-pairing in these novel superconductors has remained largely unresolved. Isotope effect studies constitute an important experimental tool for the investigation of whether or not the electron-pairing mechanism in organic superconductors is phonon-mediated, as in conventional superconductors. Recent isotope effect studies in the authors' laboratory, involving seven different isotopically labeled BEDT-TTF (or ET) derivatives, have demonstrated the following: (1) intramolecular phonon modes involving C double-bond C and Csingle bondS stretching vibrations in the ET donor molecule are not the dominant mediators of electron-pairing, and (2) in κ-(ET) 2 Cu(NCS) 2 , there exist two competing isotope effects--a normal mass effect, i.e., lowering of T c upon isotopic labeling, when the ET molecular mass is increased by concurrent 13 C and 34 S labeling, in addition to an inverse isotope effect upon deuterium labeling in ET. It is of great interest to investigate if there is an isotope effect when the charge-compensating anions, which are also located within the non-conducting layer in the superconducting cation-radical salts, are isotopically labeled. The existence of an isotope effect when the anions are labeled would be indicative of electron-pairing with the mediation of vibrational frequencies associated with the anions. In this paper, the authors present the results of the first isotope effect study in which isotopic labeling in the anion portion of κ-(ET) 2 Cu(NCS) 2 is carried out. The authors find no isotope effect when the carbon and nitrogen atoms of the thiocyanate groups in the anion are replaced with 13 C and 15 N isotopes

Structure-function relationship of a plant NCS1 member - Homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from arabidopsis

KAUST Repository

Witz, Sandra; Panwar, Pankaj; Schober, Markus; Deppe, Johannes; Pasha, Farhan Ahmad; Lemieux, M. Joanne; Mö hlmann, Torsten

2014-01-01

. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. 2014 Witz

Synthesis and characterization of small size fluorescent LEEH caped blue emission ZnTe quantum dots

Directory of Open Access Journals (Sweden)

Patnaik Sumanta Kumar

2017-04-01

Full Text Available We report here for the first time the synthesis of LEEH caped very small size (2 nm ZnTe quantum dots at low temperature (less than 100 °C using a simple chemical route. The effects of aging and stirring time on the absorption spectra of the quantum dots were investigated. The synthesized nanocrystal (NC was characterized by PL, TEM, XRD and the formation of very small size quantum dots having FCC structure was confirmed. Further, blue emission from the prepared sample was observed during exposure to monochromatic UV radiation. ZnTe NCs obtained in this study were found to be more stable compared to those presented in literature reports. ZnTe NCs may be considered as a new material in place of CdTe for optoelectronics devices.

NCS--a software for visual modeling and simulation of PWR nuclear power plant control system

International Nuclear Information System (INIS)

Cui Zhenhua

1998-12-01

The modeling and simulation of nuclear power plant control system has been investigated. Some mathematical models for rapid and accurate simulation are derived, including core models, pressurizer model, steam generator model, etc. Several numerical methods such as Runge-Kutta Method and Treanor Method are adopted to solve the above system models. In order to model the control system conveniently, a block diagram-oriented visual modeling platform is designed. And the Discrete Similarity Method is used to calculate the control system models. A corresponding simulating software, NCS, is developed for researching on the control systems of commercial nuclear power plant. And some satisfactory results are obtained. The research works will be of referential and applying value to design and analysis of nuclear power plant control system

From Too Much Freedom to Too Much Restriction: The Case of Teacher Autonomy from National Curriculum Statement (NCS) to Curriculum and Assessment Statement (CAPS)

Science.gov (United States)

Ramatlapana, K.; Makonye, J. P.

2012-01-01

The major curricula revisions in South Africa in the last two decades or so have changed the curriculum landscape. These revisions are meant to effect among other issues, the socio-economic development for all through quality education. The latest curricula transition from National Curriculum Statement (NCS) to Curriculum and Assessment Policy…

Crystal structure of mixed ligand compound [HgPhen{(C2H5)2NCS2}2] and character of intermolecular interaction in the structures of [MPhen{(C2H5)2NCS2}2] (M = Zn, Cd, Hg) complexes

International Nuclear Information System (INIS)

Klevtsova, R.F.; Glinskaya, L.A.; Zemskova, S.M.; Larionov, S.V.

2002-01-01

Monocrystals of mixed ligand complex [HgPhen(Et 2 NCS 2 ) 2 ] (Phen = 1, 10-phenanthroline) have been prepared and by the method of X-ray diffraction its crystal structure has been determined. The structure of mercury complex has been compared with structures of previously studied cadmium and zinc complexes similar in composition. The character of interaction between molecules of cadmium, zinc, mercury mixed ligand complexes and ways of their packing have been considered. It is shown that the structure of the complexes presents a molecular group assembled from two monomeric compounds at the expense of interaction between heterocyclic ligands contained in the mixed ligand complexes [ru

Synthesis and characterization of ion-implanted Pt nanocrystals in SiO2

International Nuclear Information System (INIS)

Giulian, R.; Kluth, P.; Johannessen, B.; Araujo, L.L.; Llewellyn, D.J.; Cookson, D.J.; Ridgway, M.C.

2007-01-01

Pt nanocrystals (NCs) produced by ion implantation in SiO 2 films were investigated by Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The implantations were performed at liquid nitrogen temperature using energies between 3.4 and 5.6 MeV and an ion fluence range of 2-30 x 10 16 cm -2 and were followed by annealing in forming gas (95% N 2 , 5% H 2 ) for one hour at temperatures between 500 and 1100 deg. C. TEM analysis revealed that the NCs are spherical in shape. The mean size of the NCs annealed at 1100 deg. C varied between 2.8 and 3.6 nm for the highest and lowest fluences, respectively, as determined with both TEM and SAXS. In contrast to previous studies on ion implanted metal NCs, larger Pt NCs are located far beyond the Pt peak concentration, potentially the result of a strongly defect mediated NC nucleation

The Cuban National Healthcare System: Characterization of primary healthcare services.

Directory of Open Access Journals (Sweden)

Keli Regina DAL PRÁ

2015-10-01

Full Text Available This article presents a report on the experience of healthcare professionals in Florianópolis, who took the course La Atención Primaria de Salud y la Medicina Familiar en Cuba [Primary Healthcare and Family Medicine in Cuba], in 2014. The purpose of the study is to characterize the healthcare units and services provided by the Cuban National Healthcare System (SNS and to reflect on this experience/immersion, particularly on Cuba’s Primary Healthcare Service. The results found that in comparison with Brazil’s Single Healthcare System (SUS Cuba’s SNS Family Healthcare (SF service is the central organizing element of the Primary Healthcare Service. The number of SF teams per inhabitant is different than in Brazil; the programs given priority in the APS are similar to those in Brazil and the intersectorial nature and scope of the services prove to be effective in the resolution of healthcare problems.

Standard reference and other important nuclear data. Supplement 1 to the report BNL-NCS-51123 (Dec. 1979) = ENDF-300 = IAEA-NDS-15/300 (microfiche)

Energy Technology Data Exchange (ETDEWEB)

Bhat, M R [ed.

1981-03-01

The document contains inserts to be added to the report `Standard Reference and Other Important Nuclear Data` (BNL-NCS-51123, ENDF-300), including the following two articles: Fast Neutron Capture in {sup 238}U and {sup 232}Th by W.P. Poentiz (ANL), and {sup 239}Pu Decay Power Discrepancy by T.R. England and P.G. Young (LANL) Refs, figs

ENDF/B-5 formats manual. Revised update pages of Nov. 1983. Reprint of B.A. Magurno, BNL-NCS--50496 (ENDF-102) 2nd Edition

Energy Technology Data Exchange (ETDEWEB)

Magurno, B A

1986-09-01

The ENDF-5 Format, originally the format of the US Evaluated Nuclear Data File ENDF/B-5, was internationally recommended for the computer storage, processing and exchange of evaluated neutron nuclear data. The pages included in this document serve as an update to the original ENDF-5 Formats Manual BNL-NCS-50496 [ENDF-102] 2nd Edition, October 1979. (author)

Synthesis, Structures and Properties of Cobalt Thiocyanate Coordination Compounds with 4-(hydroxymethyl)pyridine as Co-ligand

OpenAIRE

Stefan Suckert; Luzia S. Germann; Robert E. Dinnebier; Julia Werner; Christian Näther

2016-01-01

Reaction of Co(NCS)2 with 4-(hydroxymethyl)pyridine (hmpy) leads to the formation of six new coordination compounds with the composition [Co(NCS)2(hmpy))4] (1), [Co(NCS)2(hmpy)4] × H2O (1-H2O), [Co(NCS)2(hmpy)2(EtOH)2] (2), [Co(NCS)2(hmpy)2(H2O)2] (3), [Co(NCS)2(hmpy)2]n∙4 H2O (4) and [Co(NCS)2(hmpy)2]n (5). They were characterized by single crystal and powder X-ray diffraction experiments, thermal and elemental analysis, IR and magnetic measurements. Compound 1 and 1-H2O form discrete comple...

Silk fibroin/gold nanocrystals: a new example of biopolymer-based nanocomposites

Science.gov (United States)

Noinville, S.; Garnier, A.; Courty, A.

2017-05-01

The dispersion of nanoparticles in ordered polymer nanostructures can provide control over particle location and orientation, and pave the way for tailored nanomaterials that have enhanced mechanical, electrical, or optical properties. Here we used silk fibroin, a natural biopolymer, to embed gold nanocrystals (NCs), so as to obtain well-ordered structures such as nanowires and self-assembled triangular nanocomposites. Monodisperse gold NCs synthesized in organic media are mixed to silk fibroin and the obtained nanocomposites are characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and Infrared spectroscopy. The optical properties study of gold NCs and silk-gold nanocomposites shows that the Surface Plasmon band is blue shifted compared to gold NCs. The size and shape of NCs gold superlattices can be well controlled by the presence of silk fibroin giving nanowires and also self-assembled triangular nanocomposites as characterized by TEM, FE-SEM and AFM. The strong interaction between gold NCs and silk fibroin is also revealed by the conformation change of silk protein in presence of gold NCs, as shown by FTIR analysis. The formation of such ordered nanocomposites (gold NCs/silk fibroin) will provide new nanoplasmonic devices.

Locking-to-unlocking system is an efficient strategy to design DNA/silver nanoclusters (AgNCs) probe for human miRNAs

DEFF Research Database (Denmark)

Shah, Pratik; Choi, Suk Won; Kim, Ho-jin

2016-01-01

to the great sequence diversity of miRNAs in humans and other organisms, a uniform strategy for miRNA detection is attractive. The concept presented is an oligonucleotide-based locking-to-unlocking system that can be endowed with miRNA complementarity while maintaining the same secondary structure. The locking......-dependent manner. Here, the exact composition of the fold-back anchor for the locking-to-unlocking system has been systematically optimized, balancing propensity for loop-structure formation, encapsulation of emissive AgNCs and target sensitivity. It is demonstrated that the applied strategy successfully can...

Synthesis and Characterization of Rice Straw/Fe3O4 Nanocomposites by a Quick Precipitation Method

Directory of Open Access Journals (Sweden)

Katayoon Kalantari

2013-06-01

Full Text Available Small sized magnetite iron oxide nanoparticles (Fe3O4-NPs with were successfully synthesized on the surface of rice straw using the quick precipitation method in the absence of any heat treatment. Ferric chloride (FeCl3·6H2O, ferrous chloride (FeCl2·4H2O, sodium hydroxide (NaOH and urea (CH4N2O were used as Fe3O4-NPs precursors, reducing agent and stabilizer, respectively. The rice straw fibers were dispersed in deionized water, and then urea was added to the suspension, after that ferric and ferrous chloride were added to this mixture and stirred. After the absorption of iron ions on the surface layer of the fibers, the ions were reduced with NaOH by a quick precipitation method. The reaction was carried out under N2 gas. The mean diameter and standard deviation of metal oxide NPs synthesized in rice straw/Fe3O4 nanocomposites (NCs were 9.93 ± 2.42 nm. The prepared rice straw/Fe3O4-NCS were characterized using powder X-ray diffraction (PXRD, transmission electron microscopy (TEM, scanning electron microscopy (SEM, energy dispersive X-ray fluorescence (EDXF and Fourier transforms infrared spectroscopy (FT‒IR. The rice straw/Fe3O4-NCs prepared by this method have magnetic properties.

A Novel Pentadentate Coordination Mode for the Carbonato Bridge: Synthesis, Crystal Structure, and Magnetic Behavior of (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)], a New Trinuclear Nickel(II) Carbonato-Bridged Complex with Strong Antiferromagnetic Coupling.

Science.gov (United States)

Escuer, Albert; Vicente, Ramon; Kumar, Sujit B.; Solans, Xavier; Font-Bardía, Mercé; Caneschi, Andrea

1996-05-22

The trinuclear complex (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)] was obtained by reaction of basic solutions of nickel(II), Medpt (bis(3aminopropyl)methylamine) and thiocyanate ligand with atmospheric CO(2) or by simple reaction with carbonate anion. (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)] crystallizes in the triclinic system, space group P&onemacr;, with a = 12.107(5) Å, b = 12.535(7) Å, c = 16.169(9) Å, alpha = 102.69(5) degrees, beta = 92.91(5) degrees, gamma = 118.01(4) degrees, Z = 2, and R = 0.043. The three nickel atoms are asymmetrically bridged by one pentadentate carbonato ligand, which shows a novel coordination mode. The (&mgr;(3)-CO(3))[Ni(3)(Medpt)(3)(NCS)(4)] compound shows a very strong antiferromagnetic coupling. Fit as irregular triangular arrangement gave J(1) = -88.4, J(2) = -57.7, and J(3) = -9.6 cm(-)(1), which is the strongest AF coupling observed to date for Ni(3) compounds. The magnetic behavior of the carbonato bridge is discussed.

MRI characteristics of the neurocentral synchondrosis

Energy Technology Data Exchange (ETDEWEB)

Rajwani, T.; Bhargava, R. [Department of Radiology and Diagnostic Imaging, University of Alberta, 8440 112th Street, Edmonton, Alberta, Canada T6G 2H7 (Canada); Moreau, M.; Mahood, J.; Raso, V.J.; Jiang, H. [Department of Surgery, University of Alberta, 8440 112 Street, Edmonton, Alberta, Canada T6G 2H7 (Canada); Bagnall, K.M. [Division of Anatomy, University of Alberta, 8440 112 Street, Edmonton, Alberta, Canada T6G 2H7 (Canada)

2002-11-01

The neurocentral synchondrosis (NCS) is a cartilaginous growth plate that since the early 1900s has been implicated as a potential cause of adolescent idiopathic scoliosis (AIS). Previous studies have focused only on the closure age without characterizing normal NCS development. Using MRI, the normal development of the NCS image can be characterized, and the stages preceding the disappearance of this image can be specified.Methods. A total of 405 NCSs were visualized in 11 normal pediatric patients using T1 and T2 transverse and sagittal MRI views. The images were correlated and the variety of images recorded to categorize the NCS into developmental stages.Results. The development of the NCS was categorized into five developmental stages. The image of the NCS became absent in a specific pattern along the vertebral column, first in the cervical region (age 6), then in the lumbar region (age 12), and finally in the thoracic region (age 14).Conclusion. The normal development of the NCS at the level of individual vertebrae and also along the vertebral column as a whole was determined using MRI. These patterns of development are valuable and necessary to evaluate the role of the NCS in pathological conditions. (orig.)

MRI characteristics of the neurocentral synchondrosis

International Nuclear Information System (INIS)

Rajwani, T.; Bhargava, R.; Moreau, M.; Mahood, J.; Raso, V.J.; Jiang, H.; Bagnall, K.M.

2002-01-01

The neurocentral synchondrosis (NCS) is a cartilaginous growth plate that since the early 1900s has been implicated as a potential cause of adolescent idiopathic scoliosis (AIS). Previous studies have focused only on the closure age without characterizing normal NCS development. Using MRI, the normal development of the NCS image can be characterized, and the stages preceding the disappearance of this image can be specified.Methods. A total of 405 NCSs were visualized in 11 normal pediatric patients using T1 and T2 transverse and sagittal MRI views. The images were correlated and the variety of images recorded to categorize the NCS into developmental stages.Results. The development of the NCS was categorized into five developmental stages. The image of the NCS became absent in a specific pattern along the vertebral column, first in the cervical region (age 6), then in the lumbar region (age 12), and finally in the thoracic region (age 14).Conclusion. The normal development of the NCS at the level of individual vertebrae and also along the vertebral column as a whole was determined using MRI. These patterns of development are valuable and necessary to evaluate the role of the NCS in pathological conditions. (orig.)

Integration of G-quadruplex and DNA-templated Ag NCs for nonarithmetic information processing.

Science.gov (United States)

Gao, Ru-Ru; Yao, Tian-Ming; Lv, Xiao-Yan; Zhu, Yan-Yan; Zhang, Yi-Wei; Shi, Shuo

2017-06-01

To create sophisticated molecular logic circuits from scratch, you may not believe how common the building blocks can be and how diverse and powerful such circuits can be when scaled up. Using the two simple building blocks of G-quadruplex and silver nanoclusters (Ag NCs), we experimentally construct a series of multifunctional, label-free, and multi-output logic circuits to perform nonarithmetic functions: a 1-to-2 decoder, a 4-to-2 encoder, an 8-to-3 encoder, dual transfer gates, a 2 : 1 multiplexer, and a 1 : 2 demultiplexer. Moreover, a parity checker which is capable of identifying odd and even numbers from natural numbers is constructed conceptually. Finally, a multi-valued logic gate (ternary inhibit gate) is readily achieved by taking this DNA/Ag NC system as a universal platform. All of the above logic circuits share the same building blocks, indicating the great prospects of the assembly of nanomaterials and DNA for biochemical logic devices. Considering its biocompatibility, the novel prototypes developed here may have potential applications in the fields of biological computers and medical diagnosis and serve as a promising proof of principle in the not-too-distant future.

Characterization and diagnostic evaluation of chronic polyneuropathies induced by oxaliplatin and docetaxel comparing skin biopsy to quantitative sensory testing and nerve conduction studies

DEFF Research Database (Denmark)

Krøigård, T; Schrøder, H D; Qvortrup, C

2014-01-01

was to characterize the neuropathies with regard to symptoms, neurological signs and objective evidence of damage to the structure and function of the peripheral nerves. Furthermore, the diagnostic values of skin biopsy, quantitative sensory testing (QST) and nerve conduction studies (NCS) were compared. METHODS......: Patients complaining of neuropathy symptoms at least 3 months after completion of treatment with oxaliplatin (n = 20) or docetaxel (n = 20) were recruited from the Department of Oncology or using hospital records. Neuropathy scores were determined along with the intraepidermal nerve fibre density in skin....... Mechanical detection threshold was most often affected in the QST. NCS, QTS and skin biopsy were abnormal in 11, 13 and 17 and 7, 11 and 15 of the oxaliplatin-treated patients and docetaxel-treated patients, respectively. CONCLUSIONS: Chemotherapy-induced peripheral neuropathy after oxaliplatin or docetaxel...

Characterizing and Mapping of Ecosystem Services (CMESs) Literature Database Version 1.0

Science.gov (United States)

Ecosystem services (ESs) represent an ecosystem’s capacity for satisfying essential human needs, directly or indirectly, above that required to maintain ecosystem integrity (structure, function and processes). The spatial characterization and mapping of ESs is an essential first ...

Matrix-assisted relaxation in Fe(phen)2(NCS)2 spin-crossover microparticles, experimental and theoretical investigations

International Nuclear Information System (INIS)

Enachescu, Cristian; Stancu, Alexandru; Tanasa, Radu; Tissot, Antoine; Laisney, Jérôme; Boillot, Marie-Laure

2016-01-01

In this study, we present the influence of the embedding matrix on the relaxation of Fe(phen) 2 (NCS) 2 (phen = 1,10-phenanthroline) spin-transition microparticles as revealed by experiments and provide an explanation within the framework of an elastic model based on a Monte-Carlo method. Experiments show that the shape of the high-spin → low-spin relaxation curves is drastically changed when the particles are dispersed in glycerol. This effect was considered in the model by means of interactions between the microparticles and the matrix. A faster start of the relaxation for microparticles embedded in glycerol is due to an initial positive local pressure acting on the edge spin-crossover molecules from the matrix side. This local pressure diminishes and eventually becomes negative during relaxation, as an effect of the decrease of the volume of spin-crossover microparticles from high-spin to low-spin.

Simple one-pot aqueous synthesis of CdHgTe nanocrystals using sodium tellurite as the Te source

International Nuclear Information System (INIS)

Shen, Zhitao; Luo, Chunhua; Huang, Rong; Wang, Yiting; Peng, Hui; Travas-sejdic, Jadranka

2014-01-01

In this work, we systematically investigated the one-pot aqueous synthesis conditions of CdHgTe nanocrystals (NCs) using sodium tellurite (Na 2 TeO 3 ) as the Te source, and found that the added content of Hg 2+ and the initial pH value of reaction solutions significantly affected the photoluminescence quantum yield (PL QY) of alloyed CdHgTe NCs. When the concentration of Cd was 1.0 mmol L −1 , the mole ratio of Cd/Te/Hg/MPA was 1:0.5:0.05:2.4, and the initial pH value of the reaction solution was about 8.78, the PL QY of as-prepared CdHgTe NCs was up to 45%. Characterization by HRTEM and XRD confirmed the crystalline nature of CdHgTe NCs. Compared to other synthetic approaches of CdHgTe NCs, our experimental results indicate that Na 2 TeO 3 could be an attractive alternative Te source to directly synthesize CdHgTe NCs in aqueous media. - Highlights: • A one-pot method was developed for the synthesis of highly luminescent CdHgTe nanocrystals (NCs). • Sodium tellurite was used as the Te source. • The quantum yield reached up to 45%. • The experimental conditions were optimized and the prepared CdHgTe NCs were characterized

High resolution Transmission Electron Microscopy characterization of a milled oxide dispersion strengthened steel powder

Energy Technology Data Exchange (ETDEWEB)

Loyer-Prost, M., E-mail: marie.loyer-prost@cea.fr [DEN-Service de Recherches de Métallurgie Physique, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Merot, J.-S. [Laboratoire d’Etudes des Microstructures – UMR 104, CNRS/ONERA, BP72-29, Avenue de la Division Leclerc, 92 322, Châtillon (France); Ribis, J. [DEN-Service de Recherches de Métallurgie Appliquée, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Le Bouar, Y. [Laboratoire d’Etudes des Microstructures – UMR 104, CNRS/ONERA, BP72-29, Avenue de la Division Leclerc, 92 322, Châtillon (France); Chaffron, L. [DEN-Service de Recherches de Métallurgie Appliquée, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France); Legendre, F. [DEN-Service de la Corrosion et du Comportement des Matériaux dans leur Environnement, CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette (France)

2016-10-15

Oxide Dispersion Strengthened (ODS) steels are promising materials for generation IV fuel claddings as their dense nano-oxide dispersion provides good creep and irradiation resistance. Even if they have been studied for years, the formation mechanism of these nano-oxides is still unclear. Here we report for the first time a High Resolution Transmission Electron Microscopy and Energy Filtered Transmission Electron Microscopy characterization of an ODS milled powder. It provides clear evidence of the presence of small crystalline nanoclusters (NCs) enriched in titanium directly after milling. Small NCs (<5 nm) have a crystalline structure and seem partly coherent with the matrix. They have an interplanar spacing close to the (011) {sub bcc} iron structure. They coexist with larger crystalline spherical precipitates of 15–20 nm in size. Their crystalline structure may be metastable as they are not consistent with any Y-Ti-O or Ti-O structure. Such detailed observations in the as-milled grain powder confirm a mechanism of Y, Ti, O dissolution in the ferritic matrix followed by a NC precipitation during the mechanical alloying process of ODS materials. - Highlights: • We observed an ODS ball-milled powder by high resolution transmission microscopy. • The ODS ball-milled powder exhibits a lamellar microstructure. • Small crystalline nanoclusters were detected in the milled ODS powder. • The nanoclusters in the ODS milled powder are enriched in titanium. • Larger NCs of 15–20 nm in size are, at least, partly coherent with the matrix.

Reduced graphene oxide supported platinum nanocubes composites: one-pot hydrothermal synthesis and enhanced catalytic activity

International Nuclear Information System (INIS)

Li, Fumin; Gao, Xueqing; Xue, Qi; Li, Shuni; Chen, Yu; Lee, Jong-Min

2015-01-01

Reduced graphene oxide (rGO) supported platinum nanocubes (Pt-NCs) composites (Pt-NCs/rGO) were synthesized successfully by a water-based co-chemical reduction method, in which polyallylamine hydrochloride acted as a multi-functional molecule for the functionalization of graphene oxide, anchorage of Pt II precursor, and control of Pt crystal facets. The morphology, structure, composition, and catalytic property of Pt-NCs/rGO composites were characterized in detail by various spectroscopic techniques. Transmission electron microscopy images showed well-defined Pt-NCs with an average size of 9 nm uniformly distributed on the rGO surface. The as-prepared Pt-NCs/rGO composites had excellent colloidal stability in the aqueous solution, and exhibited superior catalytic activity towards the hydrogenation reduction of nitro groups compared to commercial Pt black. The improved catalytic activity originated from the abundant exposed Pt{100} facets of Pt-NCs, excellent dispersion of Pt-NCs on the rGO surface, and synergistic effect between Pt-NCs and rGO. (paper)

Scalable Fabrication of Efficient NiCo2S4 Counter Electrodes for Dye-sensitized Solar Cells Using a Facile Solution Approach

International Nuclear Information System (INIS)

Su, An-Lin; Lu, Man-Ning; Chang, Chin-Yu; Wei, Tzu-Chien; Lin, Jeng-Yu

2016-01-01

Exploiting highly electrocatalytic and cost-effectiveness counter electrodes (CEs) in dye-sensitized solar cells (DSCs) has been regarded as a persistent objective. In this work, we proposed a facile low-cost solution approach for scalable fabrication of NiCo 2 S 4 (NCS) CEs in Pt-free DSCs. Firstly, NCS particles were synthesized by means of a solvothermal method. Afterwards, the NCS particles were successfully immobilized on fluorine-doped tin oxide (FTO) glass substrate and indium doped tin oxide polyethylene naphthalate (ITO/PEN) flexible substrate as NCS CE and flexible NCS CE, respectively, by using series of dip-coating processes. On the basis of extensive electrochemical characterizations, the NCS CEs displayed Pt-like electrocatalytic activity for I 3 − reduction. The DSC based on the NCS CE achieved an impressive cell efficiency of 8.94%, which was higher than that of the cell with the conventional Pt CE (8.51%). More interesting, the DSC using the flexible NCS CE still demonstrated an acceptable cell performance of 8.62% (or 8.57% with the bended flexible NCS CE).

Service Utilization for Lifetime Mental Disorders in U.S. Adolescents: Results of the National Comorbidity Survey-Adolescent Supplement (NCS-A)

Science.gov (United States)

Merikangas, Kathleen Ries; He, Jian-ping; Burstein, Marcy; Swendsen, Joel; Avenevoli, Shelli; Case, Brady; Georgiades, Katholiki; Heaton, Leanne; Swanson, Sonja; Olfson, Mark

2011-01-01

Objective: Mental health policy for youth has been constrained by a paucity of nationally representative data concerning patterns and correlates of mental health service utilization in this segment of the population. The objectives of this investigation were to examine the rates and sociodemographic correlates of lifetime mental health service use…

Characterization of neurophysiologic and neurocognitive biomarkers for use in genomic and clinical outcome studies of schizophrenia.

Directory of Open Access Journals (Sweden)

Gregory A Light

Full Text Available Endophenotypes are quantitative, laboratory-based measures representing intermediate links in the pathways between genetic variation and the clinical expression of a disorder. Ideal endophenotypes exhibit deficits in patients, are stable over time and across shifts in psychopathology, and are suitable for repeat testing. Unfortunately, many leading candidate endophenotypes in schizophrenia have not been fully characterized simultaneously in large cohorts of patients and controls across these properties. The objectives of this study were to characterize the extent to which widely-used neurophysiological and neurocognitive endophenotypes are: 1 associated with schizophrenia, 2 stable over time, independent of state-related changes, and 3 free of potential practice/maturation or differential attrition effects in schizophrenia patients (SZ and nonpsychiatric comparison subjects (NCS. Stability of clinical and functional measures was also assessed.Participants (SZ n = 341; NCS n = 205 completed a battery of neurophysiological (MMN, P3a, P50 and N100 indices, PPI, startle habituation, antisaccade, neurocognitive (WRAT-3 Reading, LNS-forward, LNS-reorder, WCST-64, CVLT-II. In addition, patients were rated on clinical symptom severity as well as functional capacity and status measures (GAF, UPSA, SOF. 223 subjects (SZ n = 163; NCS n = 58 returned for retesting after 1 year.Most neurophysiological and neurocognitive measures exhibited medium-to-large deficits in schizophrenia, moderate-to-substantial stability across the retest interval, and were independent of fluctuations in clinical status. Clinical symptoms and functional measures also exhibited substantial stability. A Longitudinal Endophenotype Ranking System (LERS was created to rank neurophysiological and neurocognitive biomarkers according to their effect sizes across endophenotype criteria.The majority of neurophysiological and neurocognitive measures exhibited deficits in

Characterization of neurophysiologic and neurocognitive biomarkers for use in genomic and clinical outcome studies of schizophrenia.

Science.gov (United States)

Light, Gregory A; Swerdlow, Neal R; Rissling, Anthony J; Radant, Allen; Sugar, Catherine A; Sprock, Joyce; Pela, Marlena; Geyer, Mark A; Braff, David L

2012-01-01

Endophenotypes are quantitative, laboratory-based measures representing intermediate links in the pathways between genetic variation and the clinical expression of a disorder. Ideal endophenotypes exhibit deficits in patients, are stable over time and across shifts in psychopathology, and are suitable for repeat testing. Unfortunately, many leading candidate endophenotypes in schizophrenia have not been fully characterized simultaneously in large cohorts of patients and controls across these properties. The objectives of this study were to characterize the extent to which widely-used neurophysiological and neurocognitive endophenotypes are: 1) associated with schizophrenia, 2) stable over time, independent of state-related changes, and 3) free of potential practice/maturation or differential attrition effects in schizophrenia patients (SZ) and nonpsychiatric comparison subjects (NCS). Stability of clinical and functional measures was also assessed. Participants (SZ n = 341; NCS n = 205) completed a battery of neurophysiological (MMN, P3a, P50 and N100 indices, PPI, startle habituation, antisaccade), neurocognitive (WRAT-3 Reading, LNS-forward, LNS-reorder, WCST-64, CVLT-II). In addition, patients were rated on clinical symptom severity as well as functional capacity and status measures (GAF, UPSA, SOF). 223 subjects (SZ n = 163; NCS n = 58) returned for retesting after 1 year. Most neurophysiological and neurocognitive measures exhibited medium-to-large deficits in schizophrenia, moderate-to-substantial stability across the retest interval, and were independent of fluctuations in clinical status. Clinical symptoms and functional measures also exhibited substantial stability. A Longitudinal Endophenotype Ranking System (LERS) was created to rank neurophysiological and neurocognitive biomarkers according to their effect sizes across endophenotype criteria. The majority of neurophysiological and neurocognitive measures exhibited deficits in patients

Evaluation of in vitro cytotoxicity, biocompatibility, and changes in the expression of apoptosis regulatory proteins induced by cerium oxide nanocrystals

Science.gov (United States)

Khan, Shahanavaj; Ansari, Anees A.; Rolfo, Christian; Coelho, Andreia; Abdulla, Maha; Al-Khayal, Khayal; Ahmad, Rehan

2017-12-01

Cerium oxide nanocrystals (CeO2-NCs) exhibit superoxide dismutase and catalase mimetic activities. Based on these catalytic activities, CeO2-NCs have been suggested to have the potential to treat various diseases. The crystalline size of these materials is an important factor that influences the performance of CeO2-NCs. Previous reports have shown that several metal-based nanocrystals, including CeO2-NCs, can induce cytotoxicity in cancer cells. However, the underlying mechanisms have remained unclear. To characterize the anticancer activities of CeO2-NCs, several assays related to the mechanism of cytotoxicity and induction of apoptosis has been performed. Here, we have carried out a systematic study to characterize CeO2-NCs phase purity (X-ray diffraction), morphology (electron microscopy), and optical features (optical absorption, Raman scattering, and photoluminescence) to better establish their potential as anticancer drugs. Our study revealed anticancer effects of CeO2-NCs in HT29 and SW620 colorectal cancer cell lines with half-maximal inhibitory concentration (IC50) values of 2.26 and 121.18 μg ml-1, respectively. Reductions in cell viability indicated the cytotoxic potential of CeO2-NCs in HT29 cells based on inverted and florescence microscopy assessments. The mechanism of cytotoxicity confirmed by estimating possible changes in the expression levels of Bcl2, BclxL, Bax, PARP, cytochrome c, and β-actin (control) proteins in HT29 cells. Down-regulation of Bcl2 and BclxL and up-regulation of Bax, PARP, and cytochrome c proteins suggested the significant involvement of CeO2-NCs exposure in the induction of apoptosis. Furthermore, biocompatibility assay showed minimum effect of CeO2-NCs on human red blood cells.

Layered double hydroxide supported gold nanoclusters by glutathione-capped Au nanoclusters precursor method for highly efficient aerobic oxidation of alcohols

Science.gov (United States)

Li, Lun; Dou, Liguang; Zhang, Hui

2014-03-01

M3Al-layered double hydroxide (LDH, M = Mg, Ni, Co) supported Au nanoclusters (AuNCs) catalysts have been prepared for the first time by using water-soluble glutathione-capped Au nanoclusters as precursor. Detailed characterizations show that the ultrafine Au nanoclusters (ca. 1.5 +/- 0.6 nm) were well dispersed on the surface of LDH with a loading of Au below ~0.23 wt% upon synergetic interaction between AuNCs and M3Al-LDH. AuNCs/Mg3Al-LDH-0.23 exhibits much higher catalytic performance for the oxidation of 1-phenylethanol in toluene than Au/Mg3Al-LDH(DP) by the conventional deposition precipitation method and can be applied for a wide range of alcohols without basic additives. This catalyst can also be reused without loss of activity or selectivity. The AuNCs/M(= Ni, Co)3Al-LDH catalysts present even higher alcohol oxidation activity than AuNCs/Mg3Al-LDH. Particularly, AuNCs/Ni3Al-LDH-0.22 exhibits the highest activity (46 500 h-1) for the aerobic oxidation of 1-phenylethanol under solvent-free conditions attributed to its strongest Au-support synergy. The excellent activity and stability of AuNCs/M3Al-LDH catalysts render these materials promising candidates for green base-free selective oxidation of alcohols by molecular oxygen.M3Al-layered double hydroxide (LDH, M = Mg, Ni, Co) supported Au nanoclusters (AuNCs) catalysts have been prepared for the first time by using water-soluble glutathione-capped Au nanoclusters as precursor. Detailed characterizations show that the ultrafine Au nanoclusters (ca. 1.5 +/- 0.6 nm) were well dispersed on the surface of LDH with a loading of Au below ~0.23 wt% upon synergetic interaction between AuNCs and M3Al-LDH. AuNCs/Mg3Al-LDH-0.23 exhibits much higher catalytic performance for the oxidation of 1-phenylethanol in toluene than Au/Mg3Al-LDH(DP) by the conventional deposition precipitation method and can be applied for a wide range of alcohols without basic additives. This catalyst can also be reused without loss of activity

Fabrication and Characterizations of Hot-Melt Extruded Nanocomposites Based on Zinc Sulfate Monohydrate and Soluplus

Directory of Open Access Journals (Sweden)

Song Yi Lee

2017-09-01

Full Text Available Zinc sulfate monohydrate (ZnSO4-loaded nanocomposites (NCs were fabricated by using a hot-melt extruder (HME system. Soluplus (SP was adopted as an amphiphilic polymer matrix for HME processing. The micro-size of ZnSO4 dispersion was reduced to nano-size by HME processing with the use of SP. ZnSO4 could be homogeneously dispersed in SP through HME processing. ZnSO4/SP NCs with a 75 nm mean diameter, a 0.1 polydispersity index, and a −1 mV zeta potential value were prepared. The physicochemical properties of ZnSO4/SP NCs and the existence of SP in ZnSO4/SP NCs were further investigated by solid-state studies. Nano-size range of ZnSO4/SP NC dispersion was maintained in the simulated gastrointestinal environments (pH 1.2 and 6.8 media. No severe toxicity in intestinal epithelium after oral administration of ZnSO4/SP NCs (at 100 mg/kg dose of ZnSO4, single dosing was observed in rats. These results imply that developed ZnSO4/SP NC can be used as a promising nano-sized zinc supplement formulation. In addition, developed HME technology can be widely applied to fabricate nanoformulations of inorganic materials.

Matrix-assisted relaxation in Fe(phen){sub 2}(NCS){sub 2} spin-crossover microparticles, experimental and theoretical investigations

Energy Technology Data Exchange (ETDEWEB)

Enachescu, Cristian, E-mail: cristian.enachescu@uaic.ro; Stancu, Alexandru [Faculty of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); Tanasa, Radu [Faculty of Physics, “Alexandru Ioan Cuza” University, 700506 Iasi (Romania); Department of Engineering, University of Cambridge, CB2 1PZ Cambridge (United Kingdom); Tissot, Antoine [Institut de Chimie Moléculaire et des Matériaux d' Orsay, Université Paris Sud, Université Paris-Saclay, CNRS, 91405 Orsay (France); Institut Lavoisier de Versailles, UMR 8180, CNRS, Université de Versailles-Saint Quentin en Yvelines, 78035 Versailles (France); Laisney, Jérôme; Boillot, Marie-Laure, E-mail: marie-laure.boillot@u-psud.fr [Institut de Chimie Moléculaire et des Matériaux d' Orsay, Université Paris Sud, Université Paris-Saclay, CNRS, 91405 Orsay (France)

2016-07-18

In this study, we present the influence of the embedding matrix on the relaxation of Fe(phen){sub 2}(NCS){sub 2} (phen = 1,10-phenanthroline) spin-transition microparticles as revealed by experiments and provide an explanation within the framework of an elastic model based on a Monte-Carlo method. Experiments show that the shape of the high-spin → low-spin relaxation curves is drastically changed when the particles are dispersed in glycerol. This effect was considered in the model by means of interactions between the microparticles and the matrix. A faster start of the relaxation for microparticles embedded in glycerol is due to an initial positive local pressure acting on the edge spin-crossover molecules from the matrix side. This local pressure diminishes and eventually becomes negative during relaxation, as an effect of the decrease of the volume of spin-crossover microparticles from high-spin to low-spin.

Crack characterization for in-service inspection planning

International Nuclear Information System (INIS)

Waale, J.; Ekstroem, P.

1995-12-01

During in-service inspection by non destructive testing the reliability is highly dependent on how the equipment is adjusted to the specific object and to the anticipated crack feature.The crack feature and morphology vary widely between different cracking mechanisms and between material types in which the cracks appear. The major objective of this study was to characterize a number of morphology parameters for common crack mechanism and structure material combinations. Critical morphology parameters are crack orientation, shape, width, surface roughness and branching. The crack parameters were evaluated from failure analyses reported from the nuclear and non-nuclear industry. In addition, a literature review was carried out on crack parameter reports and on failure analysis reports, which were further evaluated. The evaluated crack parameters were plotted and statistically processed in data groups with respect to crack mechanism and material type. The fatigue crack mechanism were classified as mechanical, thermal or corrosion fatigue and stress corrosion crack mechanism as intergranular, transgranular or inter dendritic stress corrosion cracking. Furthermore, some common weld defects were characterized for comparison. The materials were divided into three broad groups, ferritic low alloy steels, stainless steels and nickel base alloys. The results indicate significant differences between crack parameters when comparing data from different crack mechanism/material type combinations. Typical parameter values and scatter were derived for several combinations where the data was sufficient for statistical significance. 10 refs, 105 figs, 14 tabs

Crack characterization for in-service inspection planning

Energy Technology Data Exchange (ETDEWEB)

Waale, J [SAQ Inspection Ltd, Stockholm (Sweden); Ekstroem, P [ABB Atom AB, Vaesteraas (Sweden)

1995-12-01

During in-service inspection by non destructive testing the reliability is highly dependent on how the equipment is adjusted to the specific object and to the anticipated crack feature.The crack feature and morphology vary widely between different cracking mechanisms and between material types in which the cracks appear. The major objective of this study was to characterize a number of morphology parameters for common crack mechanism and structure material combinations. Critical morphology parameters are crack orientation, shape, width, surface roughness and branching. The crack parameters were evaluated from failure analyses reported from the nuclear and non-nuclear industry. In addition, a literature review was carried out on crack parameter reports and on failure analysis reports, which were further evaluated. The evaluated crack parameters were plotted and statistically processed in data groups with respect to crack mechanism and material type. The fatigue crack mechanism were classified as mechanical, thermal or corrosion fatigue and stress corrosion crack mechanism as intergranular, transgranular or inter dendritic stress corrosion cracking. Furthermore, some common weld defects were characterized for comparison. The materials were divided into three broad groups, ferritic low alloy steels, stainless steels and nickel base alloys. The results indicate significant differences between crack parameters when comparing data from different crack mechanism/material type combinations. Typical parameter values and scatter were derived for several combinations where the data was sufficient for statistical significance. 10 refs, 105 figs, 14 tabs.

Letter of Intent for River Protection Project (RPP) Characterization Program: Process Engineering and Hanford Analytical Services and Characterization Project Operations and Quality Assurance

International Nuclear Information System (INIS)

ADAMS, M.R.

2000-01-01

The Characterization Project level of success achieved by the River Protection Project (RPP) is determined by the effectiveness of several organizations across RPP working together. The requirements, expectations, interrelationships, and performance criteria for each of these organizations were examined in order to understand the performances necessary to achieve characterization objectives. This Letter of Intent documents the results of the above examination. It formalizes the details of interfaces, working agreements, and requirements for obtaining and transferring tank waste samples from the Tank Farm System (RPP Process Engineering, Characterization Project Operations, and RPP Quality Assurance) to the characterization laboratory complex (222-S Laboratory, Waste Sampling and Characterization Facility, and the Hanford Analytical Service Program) and for the laboratory complex analysis and reporting of analytical results

Synthesis and characterization of two new zinc(II) coordination polymers with bidentate flexible ligands: Formation of a 2D structure with (44.62)-sql topology

Science.gov (United States)

Lalegani, Arash; Khaledi Sardashti, Mohammad; Gajda, Roman; Woźniak, Krzysztof

2017-12-01

Zinc(II) coordination polymers [Zn(bip)2(NCS)2]n (1) and [Zn(μ-bbd)(N3)2]n (2) were synthesized by using the neutral flexible bidentate N-donor ligands 1,4-bis(3,5-dimethylpyrazolyl)butane (bbd) and 1,3-bis(imidazolyl)propane (bip), mono-anionic NCS- or N3-ligand and zinc(II) chloride salts. The results of the X-ray analyses demonstrate that in the structure of 1, the zinc(II) ion is located on an inversion center and exhibits an ZnN6 octahedral arrangement while, in the structure of 2, the zinc(II) ion adopts an ZnN4 tetrahedral geometry. In the polymer 1, the NCS groups are terminally N-bonded to the metal center and the each bip with anti-gauche conformation acts as bridging connecting four zinc(II) ions to form a two-dimensional network with a sql [point symbol (44.62)] topology while, in the polymer 1, the N3 groups are terminally bonded to the metal center and each bbd with anti-anti-anti conformation acts as bridging ligand connecting two zinc(II) ions to form a one-dimensional zig-zag chain. Coordination compounds 1 and 2 have been characterized by infrared spectroscopy, elemental analyses and single-crystal X-ray diffraction. Thermal analyses of polymers were also presented.

School Mental Health Resources and Adolescent Mental Health Service Use

Science.gov (United States)

Green, Jennifer Greif; McLaughlin, Katie A.; Alegría, Margarita; Costello, E. Jane; Gruber, Michael J.; Hoagwood, Kimberly; Leaf, Philip J.; Olin, Serene; Sampson, Nancy A,; Kessler, Ronald C.

2014-01-01

Objective Although schools are identified as critical for detecting youth mental disorders, little is known about whether the number of mental health providers and types of resources they offer influence student mental health service use. Such information could inform the development and allocation of appropriate school-based resources to increase service use. This paper examines associations of school resources with past-year mental health service use among students with 12-month DSM-IV mental disorders. Method Data come from the U.S. National Comorbidity Survey Adolescent Supplement (NCS-A), a national survey of adolescent mental health that included 4,445 adolescent-parent pairs in 227 schools in which principals and mental health coordinators completed surveys about school resources-policies for addressing student emotional problems. Adolescents and parents completed the Composite International Diagnostic Interview and reported mental health service use across multiple sectors. Multilevel multivariate regression was used to examine associations of school mental health resources and individual-level service use. Results Roughly half (45.3%) of adolescents with a 12-month DSM-IV disorder received past-year mental health services. Substantial variation existed in school resources. Increased school engagement in early identification was significantly associated with mental health service use for adolescents with mild/moderate mental and behavior disorders. The ratio of students-to-mental health providers was not associated with overall service use, but was associated with sector of service use. Conclusions School mental health resources, particularly those related to early identification, may facilitate mental health service use and influence sector of service use for youths with DSM disorders. PMID:23622851

Capacitance-voltage characteristics of MOS capacitors with Ge nanocrystals embedded in ZrO2 gate material

International Nuclear Information System (INIS)

Lee, Hye-Ryoung; Choi, Samjong; Cho, Kyoungah; Kim, Sangsig

2007-01-01

Capacitance versus voltage (C-V) curves of Ge-nanocrystals (NCs)-embedded metal-oxide-semiconductor (MOS) capacitors are characterized in this work. Ge NCs were formed in 20-nm thick ZrO 2 gate layers by ion implantation and subsequent annealing procedures. The formation of the Ge NCs in the ZrO 2 gate layers was confirmed by high-resolution transmission electron microscopy and energy dispersive spectroscopy. The C-V curves obtained from a representative MOS capacitor embedded with the Ge NCs exhibit a 3 V memory window as bias voltage varied from 9 to - 9 V and then back to the initial positive voltage, whereas MOS capacitors without Ge NCs show negligible memory windows at the same voltage range. This indicates the presence of charge storages in the Ge NCs. The counterclockwise hysteresis observed from the C-V curves implies that electrons are trapped in Ge NCs presented inside the ZrO 2 gate layer. And our experimental results obtained from capacitance versus time measurements show good retention characteristics of Ge-NCs-embedded MOS capacitors with ZrO 2 gate material for the application of NFGM

Characterization of Silicon Nanocrystal Surfaces by Multidimensional Solid-State NMR Spectroscopy

International Nuclear Information System (INIS)

Hanrahan, Michael P.; Fought, Ellie L.; Windus, Theresa L.; Wheeler, Lance M.; Anderson, Nicholas C.

2017-01-01

The chemical and photophysical properties of silicon nanocrystals (Si NCs) are strongly dependent on the chemical composition and structure of their surfaces. Here we use fast magic angle spinning (MAS) and proton detection to enable the rapid acquisition of dipolar and scalar 2D 1 H– 29 Si heteronuclear correlation (HETCOR) solid-state NMR spectra and reveal a molecular picture of hydride-terminated and alkyl-functionalized surfaces of Si NCs produced in a nonthermal plasma. 2D 1 H– 29 Si HETCOR and dipolar 2D 1 H– 1 H multiple-quantum correlation spectra illustrate that resonances from surface mono-, di-, and trihydride groups cannot be resolved, contrary to previous literature assignments. Instead the 2D NMR spectra illustrate that there is large distribution of 1 H and 29 Si chemical shifts for the surface hydride species in both the as-synthesized and functionalized Si NCs. However, proton-detected 1 H– 29 Si refocused INEPT experiments can be used to unambiguously differentiate NMR signals from the different surface hydrides. Varying the 29 Si evolution time in refocused INEPT experiments and fitting the oscillation of the NMR signals allows for the relative populations of the different surface hydrides to be estimated. This analysis confirms that monohydride species are the predominant surface species on the as-synthesized Si NCs. A reduction in the populations of the di- and trihydrides is observed upon functionalization with alkyl groups, consistent with our previous hypothesis that the trihydride, or silyl (*SiH 3 ), group is primarily responsible for initiating surface functionalization reactions. Density functional theory (DFT) calculations were used to obtain quantum chemical structural models of the Si NC surface and reproduce the observed 1 H and 29 Si chemical shifts. Furthermore, the approaches outlined here will be useful to obtain a more detailed picture of surface structures for Si NCs and other hydride-passivated nanomaterials.

Simultaneous electrochemical detection of dopamine and uric acid over ceria supported three dimensional gold nanoclusters

Science.gov (United States)

Palanisamy, Sivakumar

2014-12-01

CeO2 is well known for being an active material to support the growth of Au nanoclusters (Au NCs). In this work, three dimensional (3D) Au NCs were deposited on three different shaped CeO2 nanostructures such as nanoparticles (NPs), nanorod arrays (NRAs) and nanoflowers (NFs) modified Ti substrate for electrochemical simultaneous detection of dopamine (DA) and uric acid (UA). The electrodeposition of 3D Au NCs were carried out via cyclic voltammetric (CV) method at over-potential, while CeO2 nanostructures were deposited by galvanostatic constant current method under the optimized conditions. The morphology and elemental composition analysis of 3D Au NCs with CeO2 nanostructures were characterized by SEM, XRD, XPS and EDAX measurements. The electrocatalytic activity of 3D Au NCs on different CeO2 supports were thoroughly investigated by using voltammetric and amperometric techniques. According to the obtained results, CeO2 NPs supported 3D Au NCs (3D Au NCs@CeO2 NPs) displayed strong signal for DA as compared to that of CeO2 NRAs (3D Au NCs@CeO2 NRAs) and CeO2 NFs supported 3D Au NCs (3D Au NCs@CeO2 NFs). In addition, the 3D Au NCs@CeO2 NPs electrode resulted in more sensitive and simultaneous detection of DA in the presence of excess UA. Thus, the 3D Au NCs@CeO2 NPs electrode can practically be applied for the detection of DA using biological samples.

Structure-function relationship of a plant NCS1 member - Homology modeling and mutagenesis identified residues critical for substrate specificity of PLUTO, a nucleobase transporter from arabidopsis

KAUST Repository

Witz, Sandra

2014-03-12

Plastidic uracil salvage is essential for plant growth and development. So far, PLUTO, the plastidic nucleobase transporter from Arabidopsis thaliana is the only known uracil importer at the inner plastidic membrane which represents the permeability barrier of this organelle. We present the first homology model of PLUTO, the sole plant NCS1 member from Arabidopsis based on the crystal structure of the benzyl hydantoin transporter MHP1 from Microbacterium liquefaciens and validated by molecular dynamics simulations. Polar side chains of residues Glu-227 and backbones of Val-145, Gly-147 and Thr-425 are proposed to form the binding site for the three PLUTO substrates uracil, adenine and guanine. Mutational analysis and competition studies identified Glu-227 as an important residue for uracil and to a lesser extent for guanine transport. A differential response in substrate transport was apparent with PLUTO double mutants E227Q G147Q and E227Q T425A, both of which most strongly affected adenine transport, and in V145A G147Q, which markedly affected guanine transport. These differences could be explained by docking studies, showing that uracil and guanine exhibit a similar binding mode whereas adenine binds deep into the catalytic pocket of PLUTO. Furthermore, competition studies confirmed these results. The present study defines the molecular determinants for PLUTO substrate binding and demonstrates key differences in structure-function relations between PLUTO and other NCS1 family members. 2014 Witz et al.

Spin crossover in Fe(phen)2(NCS)2 complexes on metallic surfaces

Science.gov (United States)

Gruber, Manuel; Miyamachi, Toshio; Davesne, Vincent; Bowen, Martin; Boukari, Samy; Wulfhekel, Wulf; Alouani, Mebarek; Beaurepaire, Eric

2017-03-01

In this review, we give an overview on the spin crossover of Fe(phen)2(NCS)2 complexes adsorbed on Cu(100), Cu2N/Cu(100), Cu(111), Co/Cu(111), Co(100), Au(100), and Au(111) surfaces. Depending on the strength of the interaction of the molecules with the substrates, the spin crossover behavior can be drastically changed. Molecules in direct contact with non-magnetic metallic surfaces coexist in both the high- and low-spin states but cannot be switched between the two. Our analysis shows that this is due to a strong interaction with the substrate in the form of a chemisorption that dictates the spin state of the molecules through its adsorption geometry. Upon reducing the interaction to the surface either by adding a second molecular layer or inserting an insulating thin film of Cu2N, the spin crossover behavior is restored and molecules can be switched between the two states with the help of scanning tunneling microscopy. Especially on Cu2N, the two states of single molecules are stable at low temperature and thus allow the realization of a molecular memory. Similarly, the molecules decoupled from metallic substrates in the second or higher layers display thermally driven spin crossover as has been revealed by X-ray absorption spectroscopy. Finally, we discuss the situation when the complex is brought into contact with a ferromagnetic substrate. This leads to a strong exchange coupling between the Fe spin in the high-spin state and the magnetization of the substrate as deduced from spin-polarized scanning tunneling spectroscopy and ab initio calculation.

Part I: Structural Characterization of Doped Nanostructured Magnesium: Understanding Disorder for Enhanced Hydrogen Absorption Kinetics Part II: Synthesis, Film Deposition, and Characterization of Quaternary Metal Chalcogenide Nanocrystals for Photovoltaic Applications

Science.gov (United States)

Braun, Max B.

The production, storage, and subsequent consumption of energy are at the foundation of all human activity and livelihood. The theme of this dissertation is the pursuit of fundamental understanding of the chemistry of materials that are used for energy production and storage. A strong emphasis is placed on a synthetic foundation that allows for systematic investigation into the fundamental chemistry that controls the applicable properties of the materials of interest. This dissertation is written in the "journals format" style--which is accepted by the Graduate School at Colorado State University--and is based on one peer-reviewed publication that has appeared in Chemistry of Materials as well as two manuscripts to be submitted, one to The Journal of Physical Chemistry C, and one to ACS Applied Materials and Interfaces. In order to create a context for these publications, Chapters 1 and 3 provide an overview of the motivations for the projects, and then continue to detail the initial synthetic investigations and considerations for the two projects. In addition to recounting Mg nanocrystals synthetic refinement that was necessary for reproducible hydride kinetic analysis, Chapter 1 also briefly introduces some of the conventional models used for fitting of the hydriding kinetics data. Furthermore, initial investigations into the use of these models for our system are presented. Chapter 2 is a paper to be submitted to The Journal of Physical Chemistry C that describes the local and extended structure characterization of Mg nanocrystals (NCs) with a small amount of nickel added during synthesis. Ni has a dramatic effect on the de/hydriding kinetics of Mg NCs, and this chapter describes the use of a combination of multiple state-of-the-art characterization techniques to gain insight into the structural perturbations due to Ni inclusion in the Mg NCs. This insight is then used to establish the characteristics of Ni inclusion that results in the enhanced hydrogen

Imaging C. elegans with thiolated tryptophan-based NIR fluorescent gold nanoclusters

Energy Technology Data Exchange (ETDEWEB)

Barman, Apurba Kr. [Indian Institute of Technology Kanpur, Department of Chemistry (India); Chaturbedi, Amaresh; Subramaniam, K. [Indian Institute of Technology Kanpur, Department of Biological Sciences and Bioengineering (India); Verma, Sandeep, E-mail: sverma@iitk.ac.in [Indian Institute of Technology Kanpur, Department of Chemistry (India)

2013-11-15

Multidentate, thiolated, tryptophan-containing peptide conjugates were synthesized for the preparation of gold nanoclusters (AuNCs). Precursor Au{sub 11}(PPh{sub 3}){sub 8}Cl{sub 3} was prepared by the reduction of HAuCl{sub 4}, followed by the use of tryptophan-containing peptide conjugates in ligand displacement reactions, to afford near-infrared fluorescent AuNCs. The emission maxima for these newly synthesized AuNCs were ∼715 nm. AuNCs were characterized with the help of UV–Vis, FTIR, fluorescence and MALDI analysis. FTIR spectra showed that the ligands bind to Au atoms through Au–S bonds, while MALDI mass spectra revealed that the clusters consisted of 20–23 Au atoms. Introduction of hydrophilic –COOH groups engendered water solubility to these AuNCs, enabling bioimaging applications. We demonstrate fluorescence imaging of the nematode C. elegans and confirm distribution of these AuNCs in nematode gut with the help of green fluorescent protein co-localization experiments.

Characterization of the institutionalization of pharmaceutical services in Brazilian primary health care.

Science.gov (United States)

Souza, Gisélia Santana; Costa, Ediná Alves; Barros, Rafael Damasceno de; Pereira, Marcelo Tavares; Barreto, Joslene Lacerda; Guerra, Augusto Afonso; Acurcio, Francisco de Assis; Guibu, Ione Aquemi; Álvares, Juliana; Costa, Karen Sarmento; Karnikowski, Margô Gomes de Oliveira; Soeiro, Orlando Mario; Leite, Silvana Nair

2017-11-13

To characterize the current stage of the institutionalization of pharmaceutical services in Brazilian cities. This study is part of the Pesquisa Nacional sobre Acesso, Utilização e Promoção do Uso Racional de Medicamentos (PNAUM - National Survey on Access, Use and Promotion of Rational Use of Medicines), a cross-sectional, exploratory, and evaluative study composed by an information survey in a representative sample of cities, stratified by Brazilian regions. We interviewed municipal secretaries of health, responsible for pharmaceutical services, and pharmacists responsible for the dispensing of medicines. The variables selected from the interviews were grouped into five dimensions that defined three stages of pharmaceutical services institutionalization: incipient (0%-34.0%), partial (35.0%-69.0%), and advanced (70.0%-100%), estimated based on the interviewees' answers. Frequencies were estimated with 95% confidence intervals. For the statistical association analysis, the Chi-square test was applied, with significance level of pautonomy in the management of financial resources. Indispensable items related to the structure expressed disparities between the regions, with statistically significant differences. The study showed a partial and heterogeneous process of institutionalization of pharmaceutical services in Brazilian cities, showing regional disparities. Variables related to the normative aspects of institutionalization were positively highlighted in all dimensions; however, it is necessary to conduct new studies to evaluate the institutionalization of pharmaceutical services' finalistic activities.

Direct versus ligand-exchange synthesis of [PtAg28(BDT)12(TPP)4]4− nanoclusters: effect of a single-atom dopant on the optoelectronic and chemical properties

KAUST Repository

Bootharaju, Megalamane Siddaramappa

2017-06-07

Heteroatom doping of atomically precise nanoclusters (NCs) often yields a mixture of doped and undoped products of single-atom difference, whose separation is extremely difficult. To overcome this challenge, novel synthesis methods are required to offer monodisperse doped NCs. For instance, the direct synthesis of PtAg28 NCs produces a mixture of [Ag29(BDT)12(TPP)4]3- and [PtAg28(BDT)12(TPP)4]4- NCs (TPP: triphenylphosphine; BDT: 1,3-benzenedithiolate). Here, we designed a ligand-exchange (LE) strategy to synthesize single-sized, Pt-doped, superatomic Ag NCs [PtAg28(BDT)12(TPP)4]4- by LE of [Pt2Ag23Cl7(TPP)10] NCs with BDTH2 (1,3-benzenedithiol). The doped NCs were thoroughly characterized by optical and photoelectron spectroscopy, mass spectrometry, total electron count, and time-dependent density functional theory (TDDFT). We show that the Pt dopant occupies the center of the PtAg28 cluster, modulates its electronic structure and enhances its photoluminescence intensity and excited-state lifetime, and also enables solvent interactions with the NC surface. Furthermore, doped NCs showed unique reactivity with metal ions - the central Pt atom of PtAg28 could not be replaced by Au, unlike the central Ag of Ag29 NCs. The achieved synthesis of single-sized PtAg28 clusters will facilitate further applications of the LE strategy for the exploration of novel multimetallic NCs.

Probing the photoluminescence properties of gold nanoclusters by fluorescence lifetime correlation spectroscopy

International Nuclear Information System (INIS)

Yuan, C. T.; Lin, T. N.; Shen, J. L.; Lin, C. A.; Chang, W. H.; Cheng, H. W.; Tang, J.

2013-01-01

Gold nanoclusters (Au NCs) have attracted much attention for promising applications in biological imaging owing to their tiny sizes and biocompatibility. So far, most efforts have been focused on the strategies for fabricating high-quality Au NCs and then characterized by conventional ensemble measurement. Here, a fusion single-molecule technique combining fluorescence correlation spectroscopy and time-correlated single-photon counting can be successfully applied to probe the photoluminescence (PL) properties for sparse Au NCs. In this case, the triplet-state dynamics and diffusion process can be observed simultaneously and the relevant time constants can be derived. This work provides a complementary insight into the PL mechanism at the molecular levels for Au NCs in solution

Self-Organized Ni Nanocrystal Embedded in BaTiO3 Epitaxial Film

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Ge FF

2010-01-01

Full Text Available Abstract Ni nanocrystals (NCs were embedded in BaTiO3 epitaxial films using the laser molecular beam epitaxy. The processes involving the self-organization of Ni NCs and the epitaxial growth of BaTiO3 were discussed. With the in situ monitoring of reflection high-energy electron diffraction, the nanocomposite films were engineered controllably by the fine alternation of the self-organization of Ni NCs and the epitaxial growth of BaTiO3. The transmission electron microscopy and the X-ray diffraction characterization confirmed that the composite film consists of the Ni NCs layers alternating with the (001/(100-oriented epitaxial BaTiO3 separation layers.

Crystal that remembers: several ways to utilize nanocrystals in resistive switching memory

International Nuclear Information System (INIS)

Banerjee, Writam; Liu, Qi; Long, Shibing; Lv, Hangbing; Liu, Ming

2017-01-01

The attractive usability of quantum phenomena in futuristic devices is possible by using zero-dimensional systems like nanocrystals (NCs). The performance of nonvolatile flash memory devices has greatly benefited from the use of NCs over recent decades. The quantum abilities of NCs have been used to improve the reliability of flash devices. Its appeal is extended to the design of emerging devices such as resistive random-access memory (RRAM), a technology where the use of silicon is optional. Here, we are going to review the recent progress in the design, characterization, and utilization of NCs in RRAM devices. We will first introduce the physical design of the RRAM devices using NCs and the improvement of electrical performance in NC-RRAM over conventional ones. In particular, special care has been taken to review the ways of development provided by the NCs in the RRAM devices. In a broad sense, the NCs can play a charge trapping role in the NC-RRAM structure or it can be responsible for the localization and improvement of the stability of the conductive filament or it can play a part in the formation of the conductive filament chain by the NC migration under applied bias. Finally, the scope of NCs in the RRAM devices has also been discussed. (topical review)

Crystal that remembers: several ways to utilize nanocrystals in resistive switching memory

Science.gov (United States)

Banerjee, Writam; Liu, Qi; Long, Shibing; Lv, Hangbing; Liu, Ming

2017-08-01

The attractive usability of quantum phenomena in futuristic devices is possible by using zero-dimensional systems like nanocrystals (NCs). The performance of nonvolatile flash memory devices has greatly benefited from the use of NCs over recent decades. The quantum abilities of NCs have been used to improve the reliability of flash devices. Its appeal is extended to the design of emerging devices such as resistive random-access memory (RRAM), a technology where the use of silicon is optional. Here, we are going to review the recent progress in the design, characterization, and utilization of NCs in RRAM devices. We will first introduce the physical design of the RRAM devices using NCs and the improvement of electrical performance in NC-RRAM over conventional ones. In particular, special care has been taken to review the ways of development provided by the NCs in the RRAM devices. In a broad sense, the NCs can play a charge trapping role in the NC-RRAM structure or it can be responsible for the localization and improvement of the stability of the conductive filament or it can play a part in the formation of the conductive filament chain by the NC migration under applied bias. Finally, the scope of NCs in the RRAM devices has also been discussed.

Characterization of trauma patients treated in a pre-hospital care service

Directory of Open Access Journals (Sweden)

Amanda de Ornelas Carvalho

2004-09-01

Full Text Available Objectives: To identify the characteristics of trauma patientstreated in a pre-hospital care service, to characterize the factorsrelated to the trauma event and quantify the severity of trauma,according to the Revised Trauma Score. Methods: This is adescriptive, exploratory, retrospective study carried out at thePre-Hospital Care Service of the Military Police - Rescue in thecity of São Paulo. Data comprised a randomized sample of 60nursing charts, distributed among the four advanced life supportunits in the city. Results: Of the occurrences dealt with, 65% arerelated to public streets, 20% are medical cases, 65% are maleindividuals, predominantly young adults. The predominantmechanisms of trauma are crash and run-over. Casa Verde wasthe care unit which obtained the highest Revised Trauma Scoreweighted mean. Conclusions: The results presented here are inconformity with the national statistics on trauma: young adults, ofworking age, involved in road accidents are most frequentlyaffected. Identifying this population is of utmost importance forthe development of preventive and educational measures.

Visible-light photocatalytic decolorization of reactive brilliant red X-3B on Cu{sub 2}O/crosslinked-chitosan nanocomposites prepared via one step process

Energy Technology Data Exchange (ETDEWEB)

Cao, Chunhua [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China); Xiao, Ling, E-mail: xiaoling9119@yahoo.cn [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Liu, Li; Zhu, Huayue [College of Resource and Environmental Science, Wuhan University, Wuhan 430072 (China); Chen, Chunhua; Gao, Lin [Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, College of Chemical and Environmental Engineering, Jianghan University, Wuhan 430056 (China)

2013-04-15

Cu{sub 2}O/crosslinked-chitosan nanocomposites (Cu{sub 2}O/CS NCs) were in situ prepared via a simple one-step liquid phase precipitation–reduction process and characterized by XRD, FT-IR, SEM, TEM, BET, XPS and UV–vis/DRS. The characterization results showed that Cu{sub 2}O/CS NCs were almost similar spherical or ellipsoidal and the surface was rough and porous because Cu{sub 2}O particle was wrapped in chitosan. The chitosan layer was especially favorable for improving the adsorption ability of dye and molecular oxygen and restraining the recombination of electrons–holes pair. The visible-light photocatalytic decolorization behavior on Cu{sub 2}O/CS NCs was evaluated using reactive brilliant red X-3B (X-3B) as a model pollutant. The influences of various experimental factors on X-3B decolorization were investigated. It was found that the photocatalytic decolorization process on Cu{sub 2}O/CS NCs followed apparent pseudo-first-order kinetics model. The dye X-3B could be decolorized more efficiently in acidic media than in alkaline media. Cu{sub 2}O/CS NCs exhibited enhanced visible-light photocatalytic activity compared with other photocatalysts reported before under similar experimental conditions.

Preparations and characterization of some carbonyl-(1-cyanoethyl)ruthenium(II) complexes

Energy Technology Data Exchange (ETDEWEB)

Hiraki, Katsuma; Ochi, Naoyuki; Kitamura, Tsuneyuki; Sasada, Yoko [Nagasaki Univ. (Japan); Shinoda, Sumio

1982-08-01

A hydridoruthenium(II) complex (RuClH(CO)(PPh/sub 3/)/sub 3/) reacted easily with acrylonitrile and fumaronitrile to give chloro-bridged binuclear (1-cyanoethyl)ruthenium(II) complexes, ((Ru(MeCHCN)Cl(CO)(PPh/sub 3/)/sub 2/)/sub 2/) (2) and ((Ru(NCCH/sub 2/CHCN)Cl(CO)(PPh/sub 3/)/sub 2/)/sub 2/), respectively. Complex 2 reacted with 4-picoline (pic), Na(BHPz/sub 3/) (Pz = 1-pyrazolyl), Na(BPz/sub 4/), and Na(Et/sub 2/NCS/sub 2/).3H/sub 2/O to afford the corresponding (1-cyanoethyl)ruthenium(II) complexes, ((Ru(MeCHCN)Cl(CO)(pic)(PPh/sub 3/))/sub 2/) (3), (Ru(MeCHCN)(BHPz/sub 3/)(CO)(PPh/sub 3/)) (accompanied by a small amount of (Ru/sub 2/(MeCHCN)/sub 2/Cl(BHPz/sub 3/)(CO)/sub 2/(PPh/sub 3/)/sub 4/)), (Ru/sub 2/(MeCHCN)/sub 2/Cl(BPz/sub 4/)(CO)/sub 2/(PPh/sub 3/)/sub 2/), and Na(Ru(MeCHCN)Cl(Et/sub 2/NCS/sub 2/)(CO)(PPh/sub 3/)), respectively. Complex 3 reacted with thallium (I) acetylacetonate (Tl(acac)), resulting in the formation of ((Ru(MeCHCN)(acac)(CO)(PPh/sub 3/))/sub 2/) and (Ru(MeCHCN)(acad)(CO)(pic)(PPh/sub 3/)). These new complexes were characterized by means of elemental analysis and spectroscopic data. The diastereoisomerism was also discussed as regards these (1-cyanoethyl)ruthenium(II) complexes.

Enhanced phosphorescence and electroluminescence in triplet emitters by doping gold into cadmium selenide/zinc sulfide nanoparticles

International Nuclear Information System (INIS)

Liu, H.-W.; Laskar, Inamur R.; Huang, C.-P.; Cheng, J.-A.; Cheng, S.-S.; Luo, L.-Y.; Wang, H.-R.; Chen, T.-M.

2005-01-01

Gold-cadmium selenide/zinc sulfide (Au-CdSe/ZnS) nanocomposites (NCs) were synthesized and characterized by transmission electron microscopy (TEM), energy dispersive X-ray (EDX) analysis, ultraviolet-visible (UV-visible) absorption and photoluminescence (PL) emission spectroscopy. The PL intensity in the Au-CdSe/ZnS NCs system was found to be much greater than that of CdSe/ZnS nanoparticles (NPs) alone, because of the surface-enhanced Raman scattering of Au NPs. Adding Au-CdSe/ZnS NCs to the cyclometalated iridium(III) complex (Ir-complex) greatly enhanced the PL intensity of a triplet emitter. Three double-layered electroluminescence (EL) devices were fabricated where the emitting zone contains the definite mixture of Ir-complex and the NCs [molar concentration of Ir-complex/NCs = 1:0 (Blank, D-1), 1:1 (D-2) and 1:3 (D-3)] and the device D-2 exhibited optimal EL performances

One-pot size-controlled growth of graphene-encapsulated germanium nanocrystals

Science.gov (United States)

Lee, Jae-Hyun; Lee, Eun-Kyung; Kang, Seog-Gyun; Jung, Su-Ho; Son, Seok-Kyun; Nam, Woo Hyun; Kim, Tae-Hoon; Choi, Byong Lyong; Whang, Dongmok

2018-05-01

To realize graphene-encapsulated semiconductor nanocrystals (NCs), an additional graphene coating process, which causes shape destruction and chemical contamination, has so far been inevitable. We report herein one-pot growth of uniform graphene-germanium core-shell nanocrystals (Ge@G NCs) in gram scale by the addition of methane as a carbon source during the thermal pyrolysis of germane. The methane plays a critical role in the growth of the graphene shell, as well as in the determination of the nucleation density and diameter of the NCs, similar to a surfactant in the liquid-phase growth of monodisperse NCs. By adjusting the gas ratio of precursors, a mixture of germane and methane, we can control the size of the Ge@G NCs in the range of ∼5-180 nm. The Ge@G NCs were characterized by various microscopic and spectroscopic tools, which indicated that the Ge core is single crystalline, and is completely covered by the graphene shell. We further investigated the merits of the graphene shell, which can enhance the electrical conductivity of nanocrystalline materials.

Origin of blue photoluminescence from colloidal silicon nanocrystals fabricated by femtosecond laser ablation in solution.

Science.gov (United States)

Hao, H L; Wu, W S; Zhang, Y; Wu, L K; Shen, W Z

2016-08-12

We present a detailed investigation into the origin of blue emission from colloidal silicon (Si) nanocrystals (NCs) fabricated by femtosecond laser ablation of Si powder in 1-hexene. High resolution transmission electron microscopy and Raman spectroscopy observations confirm that Si NCs with average size 2.7 nm are produced and well dispersed in 1-hexene. Fourier transform infrared spectrum and x-ray photoelectron spectra have been employed to reveal the passivation of Si NCs surfaces with organic molecules. On the basis of the structural characterization, UV-visible absorption, temperature-dependent photoluminescence (PL), time-resolved PL, and PL excitation spectra investigations, we deduce that room-temperature blue luminescence from colloidal Si NCs originates from the following two processes: (i) under illumination, excitons first form within colloidal Si NCs by direct transition at the X or Γ (Γ25 → Γ'2) point; (ii) and then some trapped excitons migrate to the surfaces of colloidal Si NCs and further recombine via the surface states associated with the Si-C or Si-C-H2 bonds.

Paramagnetic behavior at room temperature of Zn{sub 1−x}Mn{sub x}Te nanocrystals grown in a phosphate glass matrix by the fusion method

Energy Technology Data Exchange (ETDEWEB)

Silva, Alessandra S., E-mail: alessandra@mestrado.ufu.br [Universidade Federal de Uberlândia, Instituto de Física, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Uberlândia CEP: 38400-902 (Brazil); Franco, Adolfo; Pelegrini, Fernando [Instituto de Física, Universidade Federal de Goiás, C. P. 131, 74001-970 Goiânia, GO (Brazil); Dantas, Noelio O. [Universidade Federal de Uberlândia, Instituto de Física, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Uberlândia CEP: 38400-902 (Brazil)

2015-10-25

This work reports on the synthesis and characterization of Zn{sub 1−x}Mn{sub x}Te nanocrystals (NCs) with Mn doping concentration x varying from 0.000 to 0.800. Physical properties of samples were studied by transmission electron microscopy, magnetic force microscopy, vibrating sample magnetometry and electron paramagnetic resonance spectroscopy. Room temperature experiments revealed the size of NCs, the growth of magnetization and non-linear dependence of magnetic susceptibility on the concentration of Mn{sup 2+} ions; samples with low concentrations revealed the presence of ions in the interior and near the surface of the NCs. The results obtained confirm the paramagnetic behavior of Zn{sub 1−x}Mn{sub x}Te NCs at room temperature.

Calibration-free quantitative analysis of elemental ratios in intermetallic nanoalloys and nanocomposites using Laser Induced Breakdown Spectroscopy (LIBS).

Science.gov (United States)

Davari, Seyyed Ali; Hu, Sheng; Mukherjee, Dibyendu

2017-03-01

Intermetallic nanoalloys (NAs) and nanocomposites (NCs) have increasingly gained prominence as efficient catalytic materials in electrochemical energy conversion and storage systems. But their morphology and chemical compositions play critical role in tuning their catalytic activities, and precious metal contents. While advanced microscopy techniques facilitate morphological characterizations, traditional chemical characterizations are either qualitative or extremely involved. In this study, we apply Laser Induced Breakdown Spectroscopy (LIBS) for quantitative compositional analysis of NAs and NCs synthesized with varied elemental ratios by our in-house built pulsed laser ablation technique. Specifically, elemental ratios of binary PtNi, PdCo (NAs) and PtCo (NCs) of different compositions are determined from LIBS measurements employing an internal calibration scheme using the bulk matrix species as internal standards. Morphology and qualitative elemental compositions of the aforesaid NAs and NCs are confirmed from Transmission Electron Microscopy (TEM) images and Energy Dispersive X-ray Spectroscopy (EDX) measurements. LIBS experiments are carried out in ambient conditions with the NA and NC samples drop cast on silicon wafers after centrifugation to increase their concentrations. The technique does not call for cumbersome sample preparations including acid digestions and external calibration standards commonly required in Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) techniques. Yet the quantitative LIBS results are in good agreement with the results from ICP-OES measurements. Our results indicate the feasibility of using LIBS in future for rapid and in-situ quantitative chemical characterizations of wide classes of synthesized NAs and NCs. Copyright © 2016 Elsevier B.V. All rights reserved.

Spectroscopic characterization of ligands on the surface of water dispersible NaGdF4:Ln3+ nanocrystals

International Nuclear Information System (INIS)

Cichos, J.; Karbowiak, M.

2012-01-01

For electronic or biomedical applications it is desirable to have ligand-free water-dispersible nanocrystals (NCs). The commonly used FTIR spectroscopy often provides a direct evidence for molecules on the surface. In some cases, however, the strong bands of solvent molecules may obscure the peaks of surface bounded ligands. We show that in this regard the emission spectroscopy may be used as a more reliable probing tool. The relevant information can be obtained from emission and excitation spectra, emission decay times as well as from analysis of relative efficiency of excitation energy transfer from Gd 3+ to Eu 3+ ions. Using these methods we tested samples obtained by various synthetic routes and indicated that only nitrosonium tetrafluoroborate (NOBF 4 ) removes successfully the organic ligands from the nanocrystals surface, yielding organic ligand-free NCs dispersible in aqueous solutions. The conclusions drawn from emission spectroscopy are useful for interpretation of results of FTIR, Raman and NMR studies. The detailed assignment of FTIR peaks for oleate-capped and oleate-free NCs is also provided. Finally, we point to the risk of drawing erroneous conclusions about colloidal stability of nanocrystals if refractive indexes of NCs and medium are similar.

Spectroscopic characterization of ligands on the surface of water dispersible NaGdF4:Ln3+ nanocrystals

Science.gov (United States)

Cichos, J.; Karbowiak, M.

2012-05-01

For electronic or biomedical applications it is desirable to have ligand-free water-dispersible nanocrystals (NCs). The commonly used FTIR spectroscopy often provides a direct evidence for molecules on the surface. In some cases, however, the strong bands of solvent molecules may obscure the peaks of surface bounded ligands. We show that in this regard the emission spectroscopy may be used as a more reliable probing tool. The relevant information can be obtained from emission and excitation spectra, emission decay times as well as from analysis of relative efficiency of excitation energy transfer from Gd3+ to Eu3+ ions. Using these methods we tested samples obtained by various synthetic routes and indicated that only nitrosonium tetrafluoroborate (NOBF4) removes successfully the organic ligands from the nanocrystals surface, yielding organic ligand-free NCs dispersible in aqueous solutions. The conclusions drawn from emission spectroscopy are useful for interpretation of results of FTIR, Raman and NMR studies. The detailed assignment of FTIR peaks for oleate-capped and oleate-free NCs is also provided. Finally, we point to the risk of drawing erroneous conclusions about colloidal stability of nanocrystals if refractive indexes of NCs and medium are similar.

Synthesis and green up-conversion fluorescence of colloidal La0.78Yb0.20Er0.02F3/SiO2 core/shell nanocrystals

International Nuclear Information System (INIS)

Wang Yan; Qin Weiping; Zhang Jisen; Cao Chunyan; Zhang Jishuang; Jin Ye; Zhu Peifen; Wei Guodong; Wang Guofeng; Wang Lili

2007-01-01

Water-soluble PVP-stabilized hexagonal-phase La 0.78 Yb 0.20 Er 0.02 F 3 nanocrystals (NCs) were synthesized by hydrothermal method. The NCs were coated with a very thin silica shell, and amino groups were introduced to the surface of silica shells by copolymerization of 3-aminopropyl(triethoxy)silane. The core/shell NCs can be dispersed in ethanol and water to form stable colloidal solution. The transmission electron microscopy (TEM), selected area electron diffraction (SAED), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the core/shell materials. In addition, the green up-conversion fluorescence mechanism of La 0.78 Yb 0.20 Er 0.02 F 3 /SiO 2 NCs was studied with a 980-nm diode laser as excitation source. The water solubility, small core/shell particles size, and well colloidal stability mean the green up-conversion fluorescence NCs have potential applications in bioassay. - Graphical abstract: Colloidal La 0.78 Yb 0.20 Er 0.02 F 3 /SiO 2 Core/Shell nanocrystals (NCs) were synthesized and the free amino groups were introduced to the surface of silica shells by copolymerization 3-aminopropyl(triethoxy)silane. The NCs can be dispersed in ethanol and water to form stable colloidal solution. In addition, the NCs exhibit green up-conversion fluorescence under 980-nm excitation

Controlling Nanocrystal Superlattice Symmetry and Shape-Anisotropic Interactions through Variable Ligand Surface Coverage

KAUST Repository

Choi, Joshua J.; Bealing, Clive R.; Bian, Kaifu; Hughes, Kevin J.; Zhang, Wenyu; Smilgies, Detlef-M.; Hennig, Richard G.; Engstrom, James R.; Hanrath, Tobias

2011-01-01

The assembly of colloidal nanocrystals (NCs) into superstructures with long-range translational and orientational order is sensitive to the molecular interactions between ligands bound to the NC surface. We illustrate how ligand coverage on colloidal PbS NCs can be exploited as a tunable parameter to direct the self-assembly of superlattices with predefined symmetry. We show that PbS NCs with dense ligand coverage assemble into face-centered cubic (fcc) superlattices whereas NCs with sparse ligand coverage assemble into body-centered cubic (bcc) superlattices which also exhibit orientational ordering of NCs in their lattice sites. Surface chemistry characterization combined with density functional theory calculations suggest that the loss of ligands occurs preferentially on {100} than on reconstructed {111} NC facets. The resulting anisotropic ligand distribution amplifies the role of NC shape in the assembly and leads to the formation of superlattices with translational and orientational order. © 2011 American Chemical Society.

The synthesis of SrTiO3 nanocubes and the analysis of nearly ideal diode application of Ni/SrTiO3 nanocubes/n-Si heterojunctions

Science.gov (United States)

Bilal Taşyürek, Lütfi; Sevim, Melike; Çaldıran, Zakir; Aydogan, Sakir; Metin, Önder

2018-01-01

A perovskite type of strontium titanate (SrTiO3) nanocubes (NCs) were synthesized by using a hydrothermal process and the thin films of these NCs were deposited on an n-type silicon wafer by spin coating technique. As-synthesized SrTiO3 NCs were characterized by transmission electron microscope, scanning electron microscope, energy dispersive x-ray, x-ray diffraction and Raman spectroscopy. After evaporation of 12 Ni dots on the SrTiO3 NCs thin films deposited on n-Si, the Ni/SrTiO3 NCs/n-Si heterojunction devices were fabricated for the first time. The ideality factors of the twelve fabricated devices were vary from 1.05 to 1.22 and the barrier height values varied from 0.64 to 0.68 eV. Furthermore, since all devices yielded similar characteristics, only the current-voltage and the capacitance-voltage of one selected device (named H1) were investigated in detailed. The series resistance of this device was calculated as 96 Ω.

Controlling Nanocrystal Superlattice Symmetry and Shape-Anisotropic Interactions through Variable Ligand Surface Coverage

KAUST Repository

Choi, Joshua J.

2011-03-09

The assembly of colloidal nanocrystals (NCs) into superstructures with long-range translational and orientational order is sensitive to the molecular interactions between ligands bound to the NC surface. We illustrate how ligand coverage on colloidal PbS NCs can be exploited as a tunable parameter to direct the self-assembly of superlattices with predefined symmetry. We show that PbS NCs with dense ligand coverage assemble into face-centered cubic (fcc) superlattices whereas NCs with sparse ligand coverage assemble into body-centered cubic (bcc) superlattices which also exhibit orientational ordering of NCs in their lattice sites. Surface chemistry characterization combined with density functional theory calculations suggest that the loss of ligands occurs preferentially on {100} than on reconstructed {111} NC facets. The resulting anisotropic ligand distribution amplifies the role of NC shape in the assembly and leads to the formation of superlattices with translational and orientational order. © 2011 American Chemical Society.

Structural information on the coordination compounds formed by manganese(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and mercury(II) thiocyanates with 4-cyanopyridine N-oxide from their magnetic moments, electronic and infrared spectra

Science.gov (United States)

Ahuja, I. S.; Yadava, C. L.; Singh, Raghuvir

1982-05-01

Coordination compounds formed by the interaction of 4-cyanopyridine. N-oxide (4-CPO), a potentially bidentate ligand, with manganese(II), cobalt(II), nickel(II), zinc(II), cadmium(II) and rnercury(II) thiocyanates have been prepared and characterized from their elemental analyses, magnetic susceptibilities, electronic and infrared spectral studies down to 200 cm -1 in the solid state. The compounds isolated are: Mn(4-CPO) 2(NCS) 2, Co(4-CPO) 2(NCS) 2,Ni(4-CPO) 2(NCS) 2,Zn(4-CPO) 2(NCS) 2, Cd(4-CPO)(NCS) 2 and Hg(4-CPO) 2(SCN) 2. It is shown that 4-CPO acts as a terminal N-oxide oxygen bonded monodentate ligand in all the metal(II) thiocyanate complexes studied. Tentative stereochemistries of the complexes in the solid state are discussed. The ligand field parameters 10 Dq, B, β and λ calculated for the manganese(II), cobalt(II) and nickel(II) complexes are consistent with their proposed stereochemistries.

Generation of ultra-small InN nanocrystals by pulsed laser ablation of suspension in organic solution

Energy Technology Data Exchange (ETDEWEB)

Kursungoez, Canan; Uzcengiz Simsek, Elif; Ortac, Buelend [Bilkent University, Materials Science and Nanotechnology Department, UNAM-National Nanotechnology Research Center, Ankara (Turkey); Bilkent University, Institute of Materials Science and Nanotechnology, Ankara (Turkey); Tuzakli, Refik [Bilkent University, Materials Science and Nanotechnology Department, UNAM-National Nanotechnology Research Center, Ankara (Turkey)

2017-03-15

Nanostructures of InN have been extensively investigated since nano-size provides a number of advantages allowing applications in nanoscale electronic and optoelectronic devices. It is quite important to obtain pure InN nanocrystals (InN-NCs) to reveal the characteristic features, which gain interest in the literature. Here, we proposed a new approach for the synthesis of ultra-small hexagonal InN-NCs by using suspension of micron-sized InN powder in ethanol with pulsed laser ablation method. The liquid environment, laser energy and ablation time were optimized and a post-synthesis treatment, centrifugation, was performed to achieve InN-NCs with the smallest size. Besides, the micron-sized InN powder suspension, as a starting material, enabled us to obtain InN-NCs having diameters smaller than 5 nm. We also presented a detailed characterization of InN-NCs and demonstrated that the formation mechanism mainly depends on the fragmentation due to laser irradiation of the suspension. (orig.)

Generation of ultra-small InN nanocrystals by pulsed laser ablation of suspension in organic solution

International Nuclear Information System (INIS)

Kursungoez, Canan; Uzcengiz Simsek, Elif; Ortac, Buelend; Tuzakli, Refik

2017-01-01

Nanostructures of InN have been extensively investigated since nano-size provides a number of advantages allowing applications in nanoscale electronic and optoelectronic devices. It is quite important to obtain pure InN nanocrystals (InN-NCs) to reveal the characteristic features, which gain interest in the literature. Here, we proposed a new approach for the synthesis of ultra-small hexagonal InN-NCs by using suspension of micron-sized InN powder in ethanol with pulsed laser ablation method. The liquid environment, laser energy and ablation time were optimized and a post-synthesis treatment, centrifugation, was performed to achieve InN-NCs with the smallest size. Besides, the micron-sized InN powder suspension, as a starting material, enabled us to obtain InN-NCs having diameters smaller than 5 nm. We also presented a detailed characterization of InN-NCs and demonstrated that the formation mechanism mainly depends on the fragmentation due to laser irradiation of the suspension. (orig.)

Hybrid thin films based on bilayer heterojunction of titania nanocrystals/polypyrrole/natural dyes (Kappaphycus alvarezii) materials

Science.gov (United States)

Ghazali, Salmah Mohd; Salleh, Hasiah; Dagang, Ahmad Nazri; Ghazali, Mohd Sabri Mohd; Ali, Nik Aziz Nik; Rashid, Norlaily Abdul; Kamarulzaman, Nurul Huda; Ahmad, Wan Almaz Dhafina Che Wan

2017-09-01

In this research, hybrid thin films which consist of a combination of organic red seaweed (RS) (Kappaphycus alvarezii) and polypyrrole (PPy) with inorganic titania nanocrystals (TiO2 NCs) materials were fabricated. These hybrid thin films were fabricated accordingly with bilayer heterojunction of ITO/TiO2 NCs/PPy/RS via electrochemical method using Electrochemical Impedance Spectroscopy (EIS). The effect of number of scans (thickness) of titania on optical and electrical properties of hybrid thin films were studied. TiO2 NCs function as an electron acceptor and electronic conductor. Meanwhile, PPy acts as holes conductor and RS dye acts as a photosensitizer enhances the optical and electrical properties of the thin films. The UV absorption spectrum of TiO2 NCs, PPy and RS are characterized by UV-Visible spectroscopy, while the functional group of RS was characterized by Fourier transform infrared spectroscopy (FTIR). The UV-Vis spectra showed that TiO2 NCs, PPy and RS were absorbed over a wide range of light spectrum which were 200-300 nm, 300-900 nm and 250-900 nm; respectively. The FTIR spectra of the RS showed the presence of hydroxyl group which was responsible for a good sensitizer for these hybrid solar cells. The electrical conductivity of these hybrid thin films were measured by using four point probes. The electrical conductivity of ITO/ (1)TiO2 NCs/PPy/RS thin film under the radiation of 100 Wm-2 was 0.062 Scm-1, hence this hybrid thin films can be applied in solar cell application.

Solubility limit of Mn{sup 2+} ions in Zn{sub 1−x}Mn{sub x}Te nanocrystals grown within an ultraviolet-transparent glass template

Energy Technology Data Exchange (ETDEWEB)

Silva, Alessandra dos Santos, E-mail: alemestrado@gmail.com [Universidade Federal de Uberlândia, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física (Brazil); Silva, Sebastião William da; Morais, Paulo Cesar de [Universidade de Brasília, Núcleo de Física Aplicada, Instituto de Física (Brazil); Dantas, Noelio Oliveira [Universidade Federal de Uberlândia, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Instituto de Física (Brazil)

2016-05-15

This paper reports on the synthesis of Zn{sub 1−x}Mn{sub x}Te nanocrystals (NCs) (with 0 ≤ x ≤ 0.800) within a PZABP glass system (P{sub 2}O{sub 5}–ZnO–Al{sub 2}O{sub 3}–BaO–PbO) using the fusion method. The as-grown samples were investigated by optical absorption measurements, atomic force microscopy, X-ray diffraction, and Raman spectroscopy. The mean radius of the as-produced NCs (around R ≈ 2.2 nm) was well below the exciton Bohr radius of the bulk ZnTe (5.2 nm). All the characterization techniques employed in this report confirmed the successful inclusion of Mn{sup 2+} ions in the ZnTe-based NCs (Zn{sub 1−x}Mn{sub x}Te NCs) up to the nominal solubility limit of x = 0.100. Above this solubility limit (around x = 0.100), one can observe the formation of MnO and α-MnO{sub 2} NCs, since the nucleation rate for the formation of these NCs is greater than that of Zn{sub 1−x}Mn{sub x}Te NCs, at high x concentrations.Graphical abstract.

Eugenol nanocapsule for enhanced therapeutic activity against periodontal infections.

Science.gov (United States)

Pramod, Kannissery; Aji Alex, M R; Singh, Manisha; Dang, Shweta; Ansari, Shahid H; Ali, Javed

2016-01-01

Eugenol is a godsend to dental care due to its analgesic, local anesthetic, and anti-inflammatory and antibacterial effects. The aim of the present research work was to prepare, characterize and evaluate eugenol-loaded nanocapsules (NCs) against periodontal infections. Eugenol-loaded polycaprolactone (PCL) NCs were prepared by solvent displacement method. The nanometric size of the prepared NCs was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The in vitro drug release was found to follow a biphasic pattern and followed Michaelis-Menten like model. The percentage cell viability values near to 100 in the cell viability assay indicated that the NCs are not cytotoxic. In the in vivo studies, the eugenol NC group displayed significant difference in the continuity of epithelium of the interdental papilla in comparison to the untreated, pure eugenol and placebo groups. The in vivo performance of the eugenol-loaded NCs using ligature-induced periodontitis model in rats indicated that eugenol-loaded NCs could prevent septal bone resorption in periodontitis. On the basis of our research findings it could be concluded that eugenol-loaded PCL NCs could serve as a novel colloidal drug delivery system for enhanced therapeutic activity of eugenol in the treatment of periodontal infections.

76 FR 32980 - Telecommunications Service Priority (TSP) System

Science.gov (United States)

2011-06-07

... of Cybersecurity and Communications (CS&C), National Communications System (NCS), will submit the... Protection and Programs Directorate, Office of Cybersecurity and Communications, National Communications... occur. Affected Public: Businesses and state, local, territorial or tribal governments. Number of...

Studies on Properties of Rice Straw/Polymer Nanocomposites Based on Polycaprolactone and Fe3O4 Nanoparticles and Evaluation of Antibacterial Activity

Directory of Open Access Journals (Sweden)

Roshanak Khandanlou

2014-10-01

Full Text Available Modified rice straw/Fe3O4/polycaprolactone nanocomposites (ORS/Fe3O4/ PCL-NCs have been prepared for the first time using a solution casting method. The RS/Fe3O4-NCs were modified with octadecylamine (ODA as an organic modifier. The prepared NCs were characterized by using X-ray powder diffraction (XRD, Scanning electron microscopy (SEM, Transmission electron microscopy (TEM, Thermogravimetric analysis (TGA and Fourier transform infrared spectroscopy (FT-IR. The XRD results showed that as the intensity of the peaks decreased with the increase of ORS/Fe3O4-NCs content in comparison with PCL peaks, the Fe3O4-NPs peaks increased from 1.0 to 60.0 wt. %. The TEM and SEM results showed a good dispersion of ORS/Fe3O4-NCs in the PCL matrix and the spherical shape of the NPs. The TGA analysis indicated thermal stability of ORS/Fe3O4-NCs increased after incorporation with PCL but the thermal stability of ORS/Fe3O4/PCL-NCs decreased with the increase of ORS/Fe3O4-NCs content. Tensile strength was improved with the addition of 5.0 wt. % of ORS/Fe3O4-NCs. The antibacterial activities of the ORS/Fe3O4/PCL-NC films were examined against Gram-negative bacteria (Escherichia coli and Gram-positive bacteria (Staphylococcus aureus by diffusion method using nutrient agar. The results indicated that ORS/Fe3O4/PCL-NC films possessed a strong antibacterial activity with the increase in the percentage of ORS/Fe3O4-NCs in the PCL.

Used Nuclear Fuel Loading and Structural Performance Under Normal Conditions of Transport- Demonstration of Approach and Results on Used Fuel Performance Characterization

Energy Technology Data Exchange (ETDEWEB)

Adkins, Harold [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Geelhood, Ken [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Koeppel, Brian [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Coleman, Justin [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bignell, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flores, Gregg [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wang, Jy-An [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sanborn, Scott [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Spears, Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Klymyshyn, Nick [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-09-30

This document addresses Oak Ridge National Laboratory milestone M2FT-13OR0822015 Demonstration of Approach and Results on Used Nuclear Fuel Performance Characterization. This report provides results of the initial demonstration of the modeling capability developed to perform preliminary deterministic evaluations of moderate-to-high burnup used nuclear fuel (UNF) mechanical performance under normal conditions of storage (NCS) and normal conditions of transport (NCT) conditions. This report also provides results from the sensitivity studies that have been performed. Finally, discussion on the long-term goals and objectives of this initiative are provided.

Implantation of P ions in SiO{sub 2} layers with embedded Si nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Kachurin, G.A. E-mail: kachurin@isp.nsc.ru; Cherkova, S.G.; Volodin, V.A.; Kesler, V.G.; Gutakovsky, A.K.; Cherkov, A.G.; Bublikov, A.V.; Tetelbaum, D.I

2004-08-01

The effect of 10{sup 13}-10{sup 16} cm{sup -2} P ions implantation and of subsequent annealing on Si nanocrystals (Si-ncs), formed preliminarily in SiO{sub 2} layers by the ion-beam synthesis, has been studied. Photoluminescence (PL), Raman spectroscopy, high resolution electron microscopy (HREM), X-Ray Photoelectron Spectroscopy (XPS) and optical absorption were used for characterizations. The low fluence implantations have shown even individual displacements in Si-ncs quench their PL. Restoration of PL from partly damaged Si-ncs proceeds at annealing less than 1000 deg. C. In the low fluence implanted and annealed samples an increased Si-ncs PL has been found and ascribed to the radiation-induced shock crystallization of stressed Si nanoprecipitates. Annealing at temperatures under 1000 deg. C are inefficient when P ion fluences exceed 10{sup 14} cm{sup -2}, thus becoming capable to amorphize Si-ncs. High crystallization temperature of the amorphized Si-ncs is attributed to a counteraction of their shell layers. After implantation of the highest P fluences an enhanced recovery of PL was found from P concentration over 0.1 at.%. Raman spectroscopy and HREM showed an increased Si-ncs number in such layers. The effect resembles the impurity-enhanced crystallization, known for heavily doped bulk Si. This effect, along with the data obtained by XPS, is considered as an indication P atoms are really present inside the Si-ncs. However, no evidence of free electrons appearance has been observed. The fact is explained by an increased interaction of electrons with the donor nuclei in Si-ncs.

Implantation of P ions in SiO2 layers with embedded Si nanocrystals

International Nuclear Information System (INIS)

Kachurin, G.A.; Cherkova, S.G.; Volodin, V.A.; Kesler, V.G.; Gutakovsky, A.K.; Cherkov, A.G.; Bublikov, A.V.; Tetelbaum, D.I.

2004-01-01

The effect of 10 13 -10 16 cm -2 P ions implantation and of subsequent annealing on Si nanocrystals (Si-ncs), formed preliminarily in SiO 2 layers by the ion-beam synthesis, has been studied. Photoluminescence (PL), Raman spectroscopy, high resolution electron microscopy (HREM), X-Ray Photoelectron Spectroscopy (XPS) and optical absorption were used for characterizations. The low fluence implantations have shown even individual displacements in Si-ncs quench their PL. Restoration of PL from partly damaged Si-ncs proceeds at annealing less than 1000 deg. C. In the low fluence implanted and annealed samples an increased Si-ncs PL has been found and ascribed to the radiation-induced shock crystallization of stressed Si nanoprecipitates. Annealing at temperatures under 1000 deg. C are inefficient when P ion fluences exceed 10 14 cm -2 , thus becoming capable to amorphize Si-ncs. High crystallization temperature of the amorphized Si-ncs is attributed to a counteraction of their shell layers. After implantation of the highest P fluences an enhanced recovery of PL was found from P concentration over 0.1 at.%. Raman spectroscopy and HREM showed an increased Si-ncs number in such layers. The effect resembles the impurity-enhanced crystallization, known for heavily doped bulk Si. This effect, along with the data obtained by XPS, is considered as an indication P atoms are really present inside the Si-ncs. However, no evidence of free electrons appearance has been observed. The fact is explained by an increased interaction of electrons with the donor nuclei in Si-ncs

The Enhanced Catalytic Activities of Asymmetric Au-Ni Nanoparticle Decorated Halloysite-Based Nanocomposite for the Degradation of Organic Dyes

Science.gov (United States)

Jia, Lei; Zhou, Tao; Xu, Jun; Li, Xiaohui; Dong, Kun; Huang, Jiancui; Xu, Zhouqing

2016-02-01

Janus particles (JPs) are unique among the nano-/microobjects because they provide asymmetry and can thus impart drastically different chemical or physical properties. In this work, we have fabricated the magnetic halloysite nanotube (HNT)-based HNTs@Fe3O4 nanocomposite (NCs) and then anchored the Janus Au-Ni or isotropic Au nanoparticles (NPs) to the surface of external wall of sulfydryl modified magnetic nanotubes. The characterization by physical methods authenticates the successful fabrication of two different magnetic HNTs@Fe3O4@Au and HNTs@Fe3O4@Au-Ni NCs. The catalytic activity and recyclability of the two NCs have been evaluated considering the degradation of Congo red (CR) and 4-nitrophenol (4-NP) using sodium borohydride as a model reaction. The results reveal that the symmetric Au NPs participated NCs display low activity in the degradation of the above organic dyes. However, a detailed kinetic study demonstrates that the employ of bimetallic Janus Au-Ni NPs in the NCs indicates enhanced catalytic activity, owing to the structurally specific nature. Furthermore, the magnetic functional NCs reported here can be used as recyclable catalyst which can be recovered simply by magnet.

Anomalous behaviour of the in-plane electrical conductivity of the layered superconductor kappa-(BEDT-TTF) sub 2 Cu(NCS) sub 2

CERN Document Server

Singleton, J; Hayes, W; Schlüter, J A

2003-01-01

The apparent quasiparticle scattering rates in high-quality crystals of the quasi-two-dimensional superconductor kappa-(BEDT-TTF) sub 2 Cu(NCS) sub 2 are studied using the Shubnikov-de Haas effect and megahertz penetration-depth experiments. The width of the superconducting transition observed in the megahertz experiments, taken in conjunction with the field dependence of the Shubnikov-de Haas oscillations, gives evidence that the broadening of the Landau levels is primarily caused by spatial inhomogeneities. This indicates a quasiparticle lifetime for the Landau states >> 3 ps. The megahertz data can also be used to derive an apparent scattering time (0.14- 0.56 ps) from the skin depth. This is much shorter than the Landau-state lifetime, in strong contrast to the expectations of Landau Fermi-liquid theory. The simplest explanation for the data is that only a fraction of the crystal contributes to the metallic conductivity, an observation which may be related to the recently observed 'glassy' transition in k...

Characterization of the institutionalization of pharmaceutical services in Brazilian primary health care

Directory of Open Access Journals (Sweden)

Gisélia Santana Souza

2017-11-01

Full Text Available ABSTRACT OBJECTIVE To characterize the current stage of the institutionalization of pharmaceutical services in Brazilian cities. METHODS This study is part of the Pesquisa Nacional sobre Acesso, Utilização e Promoção do Uso Racional de Medicamentos (PNAUM – National Survey on Access, Use and Promotion of Rational Use of Medicines, a cross-sectional, exploratory, and evaluative study composed by an information survey in a representative sample of cities, stratified by Brazilian regions. We interviewed municipal secretaries of health, responsible for pharmaceutical services, and pharmacists responsible for the dispensing of medicines. The variables selected from the interviews were grouped into five dimensions that defined three stages of pharmaceutical services institutionalization: incipient (0%-34.0%, partial (35.0%-69.0%, and advanced (70.0%-100%, estimated based on the interviewees’ answers. Frequencies were estimated with 95% confidence intervals. For the statistical association analysis, the Chi-square test was applied, with significance level of p<0.05. RESULTS Our results show a partial and heterogeneous process of institutionalization of pharmaceutical services in Brazil, and an advanced stage in formal structures, such as the municipal health plans and the existence of a standardized list of medicines. The analysed variables in the “organization, structure, and financing” dimension configured stages that range from partial to advanced. The management presented partial institutionalization, positively showing the existence of computerized system, but also disparate results regarding the autonomy in the management of financial resources. Indispensable items related to the structure expressed disparities between the regions, with statistically significant differences. CONCLUSION The study showed a partial and heterogeneous process of institutionalization of pharmaceutical services in Brazilian cities, showing regional

47 CFR Appendix to Part 216 - NCS Directives

Science.gov (United States)

2010-10-01

... responsive and survivable national telecommunications infrastructure to meet the NSEP telecommunications... telecommunications infrastructure and service capabilities within the framework outlined in Executive Order No. 12472... Surveillance Act (50 U.S.C. 1801, et seq. and 18 U.S.C. 2511, 2518, and 2519). e. Title 47, Code of Federal...

Neocarzinostatin as a probe for DNA protection activity--molecular interaction with caffeine.

Science.gov (United States)

Chin, Der-Hang; Li, Huang-Hsien; Kuo, Hsiu-Maan; Chao, Pei-Dawn Lee; Liu, Chia-Wen

2012-04-01

Neocarzinostatin (NCS), a potent mutagen and carcinogen, consists of an enediyne prodrug and a protein carrier. It has a unique double role in that it intercalates into DNA and imposes radical-mediated damage after thiol activation. Here we employed NCS as a probe to examine the DNA-protection capability of caffeine, one of common dietary phytochemicals with potential cancer-chemopreventive activity. NCS at the nanomolar concentration range could induce significant single- and double-strand lesions in DNA, but up to 75 ± 5% of such lesions were found to be efficiently inhibited by caffeine. The percentage of inhibition was caffeine-concentration dependent, but was not sensitive to the DNA-lesion types. The well-characterized activation reactions of NCS allowed us to explore the effect of caffeine on the enediyne-generated radicals. Postactivation analyses by chromatographic and mass spectroscopic methods identified a caffeine-quenched enediyne-radical adduct, but the yield was too small to fully account for the large inhibition effect on DNA lesions. The affinity between NCS chromophore and DNA was characterized by a fluorescence-based kinetic method. The drug-DNA intercalation was hampered by caffeine, and the caffeine-induced increases in DNA-drug dissociation constant was caffeine-concentration dependent, suggesting importance of binding affinity in the protection mechanism. Caffeine has been shown to be both an effective free radical scavenger and an intercalation inhibitor. Our results demonstrated that caffeine ingeniously protected DNA against the enediyne-induced damages mainly by inhibiting DNA intercalation beforehand. The direct scavenging of the DNA-bound NCS free radicals by caffeine played only a minor role. Copyright © 2011 Wiley Periodicals, Inc.

Synthesis, Structures and Properties of Cobalt Thiocyanate Coordination Compounds with 4-(hydroxymethylpyridine as Co-ligand

Directory of Open Access Journals (Sweden)

Stefan Suckert

2016-04-01

Full Text Available Reaction of Co(NCS2 with 4-(hydroxymethylpyridine (hmpy leads to the formation of six new coordination compounds with the composition [Co(NCS2(hmpy4] (1, [Co(NCS2(hmpy4] × H2O (1-H2O, [Co(NCS2(hmpy2(EtOH2] (2, [Co(NCS2(hmpy2(H2O2] (3, [Co(NCS2(hmpy2]n∙4 H2O (4 and [Co(NCS2(hmpy2]n (5. They were characterized by single crystal and powder X-ray diffraction experiments, thermal and elemental analysis, IR and magnetic measurements. Compound 1 and 1-H2O form discrete complexes, in which the Co(II cations are octahedrally coordinated by two terminal thiocyanato anions and four 4-(hydroxymethylpyridine ligands. Discrete complexes were also observed for compounds 2 and 3 where two of the hmpy ligands were substituted by solvent, either water (3 or ethanol (2. In contrast, in compounds 4 and 5, the Co(II cations are linked into chains by bridging 4-(hydroxymethylpyridine ligands. The phase purity was checked with X-ray powder diffraction. Thermogravimetric measurements showed that compound 3 transforms into 5 upon heating, whereas the back transformation occurs upon resolvation. Magnetic measurements did not show any magnetic exchange via the hmpy ligand for compound 5.

Comparative study on antifungal activities of chitosan nanoparticles and chitosan silver nano composites against Fusarium oxysporum species complex.

Science.gov (United States)

Dananjaya, S H S; Erandani, W K C U; Kim, Cheol-Hee; Nikapitiya, Chamilani; Lee, Jehee; De Zoysa, Mahanama

2017-12-01

Though the metal nanoparticles (NPs) have been shown favorable results against fungal diseases, erratic environmental toxicity of NPs have raised serious concerns against their applications. Hence, it is vital to modify antifungal compounds into safe substitutes over synthetic chemicals. In this study, antifungal effects of chitosan nanoparticles (CNPs) and chitosan silver nanocomposites (CAgNCs) were compared against Fusarium oxysporum species complex. CNPs and CAgNCs were synthesized, characterized and compared based on the transmission electron microscope, X-ray diffraction, UV-vis absorbance spectra, particle size distribution, zeta potential and thermal stability analysis. Ultra-structural analysis on mycelium membrane of treated F. oxysporum showed that CNPs and CAgNCs could induce a pronounced membrane damage and disruption of the mycelium surface, increase the membrane permeability, and even cell disintegration. CAgNCs showed a significantly higher radial growth inhibition than CNPs in all the tested concentrations. Both CNPs and CAgNCs were not only effective in reducing the fungal growth, but also caused morphological and ultrastructural changes in the pathogen, thereby suggesting its usage as an antifungal dispersion system to control F. oxysporum. Additionally, CNPs and CAgNCs therapy reduced the F. oxysporum infection in zebrafish. Data demonstrates biologically active CNPs and CAgNCs are promising antifungal agents against F. oxysporum. Copyright © 2017 Elsevier B.V. All rights reserved.

Sonochemical synthesis of PVA/PVP blend nanocomposite containing modified CuO nanoparticles with vitamin B1 and their antibacterial activity against Staphylococcus aureus and Escherichia coli.

Science.gov (United States)

Mallakpour, Shadpour; Mansourzadeh, Soheila

2018-05-01

The aim of this paper was to blend the polymers, poly(N-vinyl-2-pyrrolidone) (PVP) and poly(vinyl alcohol) (PVA) to produce a novel composite materials possessing the benefits of both. CuO nanoparticles (NPs) were used as a suitable filler to fabricate the blend nanocomposites (NCs) with desired properties. First, the surface of NPs, was modified with vitamin B 1 (VB 1 ) as a bio-safe coupling agent. Then, the blend NCs with various ratios of modified CuO (3, 5, and 7 wt%) were fabricated under ultrasonic irradiations followed by casting/solvent evaporation method. These processes are fast and green way to disperse the NPs sufficiently. Several techniques were applied for the characterization of the obtained NCs. morphology examination demonstrated the morphology of NCs and compatibility of NPs with the blend polymer. EDX results indicated the weight and atomic percentage of the achieved materials. TGA analysis verified that the NCs show higher thermal properties than the neat blend polymer. Also embedding the modified NPs into the blend polymer had effected on optical absorbance of the obtained NCs. The contact angle measurements confirmed that the hydrophilicity decreased for different proportions of the modified NPs loaded in the blend polymer. Finally, NCs show better bactericidal effects against gram-positive than gram-negative bacteria. Copyright © 2018 Elsevier B.V. All rights reserved.

Synthesis of highly fluorescent and thio-linkers stabilize gold quantum dots and nano clusters in DMF for bio-labeling

Energy Technology Data Exchange (ETDEWEB)

Rastogi, Shiva K., E-mail: srastogi@uidaho.edu [University of Idaho, Department of Chemistry (United States); Denn, Benjamin D.; Branen, A. Larry [University of Idaho, Coeur D' Alene, Biosensors and Nanotechnology Application Laboratory (BNAL) (United States)

2012-01-15

This study demonstrates a one versus two-step synthesis of fluorescent gold quantum dots (F-AuQDs) and nano clusters (F-AuNCs) functionalized with thiolated organic linkers using reduction of gold precursor in N,N Prime -dimethylformamide in 1 h of reaction. The F-AuQDs and F-AuNCs show fluorescence emission at 425 {+-} 5 nm upon excitation at 345 {+-} 5 nm of wavelength, with good water solubility and stability. Five different thiolated organic binary linkers consisting of various functional groups including: carboxylic acid, hydroxyl, and aromatic amine, were conjugated with the F-AuQDs and F-AuNCs. The formation mechanism and functionalization of the F-AuQDs and F-AuNCs was characterized using UV-vis absorption spectra, UV-vis light, fluorescent emission spectra, pH, TEM, and FTIR. The fluorescence emission of the F-AuQDs and F-AuNCs is greatly dependent on the thio-linker. This novel one-step approach provides facile and fast synthesis of F-AuQDs and F-AuNCs over the two-step method, with less than 5 h of reaction and workup compared to more than 28 h of reaction for the two-step approach. These thio-linker functionalized F-AuQDs and F-AuNCs have a wide application in fluorescent labeling of biomolecules, optical devices, imaging, energy transfer, and biosensing.

Physical and optical properties of size-selective CdTe nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Fok, Alice [Department of Chemistry, The City College of New York, CUNY New York, NY 10031 (United States); Morales, Jorge [Department of Biology, City College of New York, CUNY New York, NY 10031 (United States); Sohel, Mohammad [Natural Sciences Department, Hostos College, CUNY Bronx, NY 10451 (United States)

2010-06-15

Physical and optical properties of colloidal cadmium telluride nanocrystals (CdTe NCs) were investigated. The CdTe NCs were synthesized by reacting elemental tellurium dissolved in tributylphosphine with a mixture of cadmium oxide, octadecene, and oleic acid. These NCs, which were characterized by transmission electron microscopy (TEM) are spherical and ranged from 5 to 7 nm in diameter. The identity of the compound post-synthesis was confirmed by X-Ray diffraction (XRD) patterns. UV-Vis and photoluminescence (PL) properties as grown and pure CdTe samples were investigated. Bright excitonic photoluminescence emission was observed (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Controlled fabrication of Si nanocrystal delta-layers in thin SiO{sub 2} layers by plasma immersion ion implantation for nonvolatile memories

Energy Technology Data Exchange (ETDEWEB)

Bonafos, C.; Ben-Assayag, G.; Groenen, J.; Carrada, M. [CEMES-CNRS and Université de Toulouse, 29 rue J. Marvig, 31055 Toulouse Cedex 04 (France); Spiegel, Y.; Torregrosa, F. [IBS, Rue G Imbert Prolongée, ZI Peynier-Rousset, 13790 Peynier (France); Normand, P.; Dimitrakis, P.; Kapetanakis, E. [NCSRD, Terma Patriarchou Gregoriou, 15310 Aghia Paraskevi (Greece); Sahu, B. S.; Slaoui, A. [ICube, 23 Rue du Loess, 67037 Strasbourg Cedex 2 (France)

2013-12-16

Plasma Immersion Ion Implantation (PIII) is a promising alternative to beam line implantation to produce a single layer of nanocrystals (NCs) in the gate insulator of metal-oxide semiconductor devices. We report herein the fabrication of two-dimensional Si-NCs arrays in thin SiO{sub 2} films using PIII and rapid thermal annealing. The effect of plasma and implantation conditions on the structural properties of the NC layers is examined by transmission electron microscopy. A fine tuning of the NCs characteristics is possible by optimizing the oxide thickness, implantation energy, and dose. Electrical characterization revealed that the PIII-produced-Si NC structures are appealing for nonvolatile memories.

Controlled fabrication of Si nanocrystal delta-layers in thin SiO2 layers by plasma immersion ion implantation for nonvolatile memories

International Nuclear Information System (INIS)

Bonafos, C.; Ben-Assayag, G.; Groenen, J.; Carrada, M.; Spiegel, Y.; Torregrosa, F.; Normand, P.; Dimitrakis, P.; Kapetanakis, E.; Sahu, B. S.; Slaoui, A.

2013-01-01

Plasma Immersion Ion Implantation (PIII) is a promising alternative to beam line implantation to produce a single layer of nanocrystals (NCs) in the gate insulator of metal-oxide semiconductor devices. We report herein the fabrication of two-dimensional Si-NCs arrays in thin SiO 2 films using PIII and rapid thermal annealing. The effect of plasma and implantation conditions on the structural properties of the NC layers is examined by transmission electron microscopy. A fine tuning of the NCs characteristics is possible by optimizing the oxide thickness, implantation energy, and dose. Electrical characterization revealed that the PIII-produced-Si NC structures are appealing for nonvolatile memories

Synthesis and optical study of green light emitting polymer coated CdSe/ZnSe core/shell nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Tripathi, S.K., E-mail: surya@pu.ac.in [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh 160 014 (India); Sharma, Mamta [Department of Physics, Center of Advanced Study in Physics, Panjab University, Chandigarh 160 014 (India)

2013-05-15

Highlights: ► Synthesis of Polymer coated core CdSe and CdSe/ZnSe core/shell NCs. ► From TEM image, the spherical nature of CdSe and CdSe/ZnSe is obtained. ► Exhibiting green band photoemission peak at 541 nm and 549 nm for CdSe core and CdSe/ZnSe core/shell NCs. ► The shell thickness has been calculated by using superposition of quantum confinement energy model. - Abstract: CdSe/ZnSe Core/Shell NCs dispersed in PVA are synthesized by chemical method at room temperature. This is characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV/Vis spectra and photoluminescence spectroscopy (PL). TEM image shows the spherical nature of CdSe/ZnSe core/shell NCs. The red shift of absorption and emission peak of CdSe/ZnSe core/shell NCs as compared to CdSe core confirmed the formation of core/shell. The superposition of quantum confinement energy model is used for calculation of thickness of ZnSe shell.

Highly sensitive and stable Ag@SiO2 nanocubes for label-free SERS-photoluminescence detection of biomolecules

Science.gov (United States)

Nguyen, Minh-Kha; Su, Wei-Nien; Chen, Ching-Hsiang; Rick, John; Hwang, Bing-Joe

2017-03-01

Surface-enhanced Raman scattering (SERS) and fluorescence microscopy are a widely used biological and chemical characterization techniques. However, the peak overlapping in multiplexed experiments and rapid photobleaching of fluorescent organic dyes is still the limitations. When compared to Ag nanocubes (NCs), higher SERS sensitivities can be obtained with thin shelled silica Ag@SiO2 NCs, in contrast metal-enhanced photoluminescence (MEPL) is only found with NCs that have thicker silica shells. A 'dual functionality' represented by the simultaneous strengthening of SERS and MEPL signals can be achieved by mixing Ag@SiO2 NCs, with a silica shell thickness of 1.5 nm and 4.4 nm. This approach allows both the Ag@SiO2 NCs SERS and MEPL sensitivities to be maintained at 90% after 12 weeks of storage. Based on the distinguished detection of creatinine and flavin adenine dinucleotide in the mixture, the integration of SERS and MEPL together on a stable single plasmonic nanoparticle platform offers an opportunity to enhance both biomarker detection sensitivity and specificity.

Preparation and physicochemical characterization of anionic uranyl. beta. -ketoenolates

Energy Technology Data Exchange (ETDEWEB)

Marangoni, G; Paolucci, G [Consiglio Nazionale delle Ricerche, Padua (Italy). Lab. di Chimica e Tecnologia dei Radioelementi; Graziani, R; Celon, E

1978-01-01

New classes of anionic uranyl ..beta..-ketoenolates of formula (UO/sub 2/L/sub 2/X)/sup -/ (where L = 1,3-diphenylpropane-1,3-dionate (dppd), 4,4,4-trifluoro-1-phenylbutane-1,3-dionate (tfpbd), or 1-phenylbutane-1,3-dionate (pbd); X = Cl/sup -/, Br/sup -/, I/sup -/, (NO/sub 3/)/sup -/, (O/sub 2/CMe)/sup -/, or (NCS)/sup -/) and (L/sub 2/O/sub 2/U(..mu..-X) UO/sub 2/L/sub 2/)/sup -/ (where X = F/sup -/, and also Cl/sup -/ only in the case of L = dppd) have been synthesized and characterized by a number of physical measurements. The different ability of the various anionic ligands to enter into the co-ordination sphere of the uranyl ion, their potentially different bonding modes, and the possible correlations between physical parameters and the nature of either the chelate substituents or the anionic ligand are discussed.

Intrusion Detection in Networked Control Systems: From System Knowledge to Network Security

OpenAIRE

Caselli, M.

2016-01-01

“Networked control system‿ (NCS) is an umbrella term encompassing a broad variety of infrastructures such as industrial control systems (ICSs) and building automation systems (BASs). Nowadays, all these infrastructures play an important role in several aspects of our daily life, from managing essential services such as en- ergy and water (e.g., critical infrastructures) to monitoring the increasingly smart environments that surround us (e.g., the Internet of Things). Over the years, NCS techn...

Magnetic and structural properties of ferrihydrite/hematite nanocomposites

International Nuclear Information System (INIS)

Pariona, N.; Camacho-Aguilar, K.I.; Ramos-González, R.; Martinez, Arturo I.; Herrera-Trejo, M.; Baggio-Saitovitch, E.

2016-01-01

A rich variety of ferrihydrite/hematite nanocomposites (NCs) with specific size, composition and properties were obtained in transformation reactions of 2-line ferrihydrite. Transmission electron microscopy (TEM) observations showed that the NCs consist of clusters of strongly aggregated nanoparticles (NPs) similarly to a “plum pudding”, where hematite NPs “raisins” are surrounded by ferrihydrite “pudding”. Magnetic measurements of the NCs correlate very well with TEM results; i.e., higher coercive fields correspond to greater hematite crystallite size. First order reversal curve (FORC) measurements were used for the characterization of the magnetic components of the NCs. FORC diagrams revealed that the NCs prepared at short times are composed by single domains with low coercivity, and NCs prepared at times larger than 60 min exhibited elongated distribution along the Hc axis. It suggested that these samples consist of mixtures of different kinds of hematite particles, ones with low coercivity and others with coercivity greater than 600 Oe. For NCs prepared at times larger than 60 min, Mossbauer spectroscopy revealed the presence of two sextets, which one was assigned to fine hematite particles and other to hematite particles with hyperfine parameters near to bulk hematite. The correlation of the structural and magnetic properties of the ferrihydrite/hematite NCs revealed important characteristics of these materials which have not been reported elsewhere. - Highlights: • Ferrihydrite/hematite nanocomposites were prepared. • The “plum pudding” morphology of the ferrihydrite/hematite nanocomposites was found. • The FORC diagrams of ferrihydrite/hematite nanocomposites have been measured.

Magnetic and structural properties of ferrihydrite/hematite nanocomposites

Energy Technology Data Exchange (ETDEWEB)

Pariona, N.; Camacho-Aguilar, K.I.; Ramos-González, R. [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav-Saltillo, Av. Industria Metalúrgica 1062, Parque Industrial Ramos Arizpe, Coahuila 25900 (Mexico); Martinez, Arturo I., E-mail: mtz.art@gmail.com [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav-Saltillo, Av. Industria Metalúrgica 1062, Parque Industrial Ramos Arizpe, Coahuila 25900 (Mexico); Herrera-Trejo, M. [Center for Research and Advanced Studies of the National Polytechnic Institute, Cinvestav-Saltillo, Av. Industria Metalúrgica 1062, Parque Industrial Ramos Arizpe, Coahuila 25900 (Mexico); Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Físicas, Río de Janeiro 22290-180 (Brazil)

2016-05-15

A rich variety of ferrihydrite/hematite nanocomposites (NCs) with specific size, composition and properties were obtained in transformation reactions of 2-line ferrihydrite. Transmission electron microscopy (TEM) observations showed that the NCs consist of clusters of strongly aggregated nanoparticles (NPs) similarly to a “plum pudding”, where hematite NPs “raisins” are surrounded by ferrihydrite “pudding”. Magnetic measurements of the NCs correlate very well with TEM results; i.e., higher coercive fields correspond to greater hematite crystallite size. First order reversal curve (FORC) measurements were used for the characterization of the magnetic components of the NCs. FORC diagrams revealed that the NCs prepared at short times are composed by single domains with low coercivity, and NCs prepared at times larger than 60 min exhibited elongated distribution along the Hc axis. It suggested that these samples consist of mixtures of different kinds of hematite particles, ones with low coercivity and others with coercivity greater than 600 Oe. For NCs prepared at times larger than 60 min, Mossbauer spectroscopy revealed the presence of two sextets, which one was assigned to fine hematite particles and other to hematite particles with hyperfine parameters near to bulk hematite. The correlation of the structural and magnetic properties of the ferrihydrite/hematite NCs revealed important characteristics of these materials which have not been reported elsewhere. - Highlights: • Ferrihydrite/hematite nanocomposites were prepared. • The “plum pudding” morphology of the ferrihydrite/hematite nanocomposites was found. • The FORC diagrams of ferrihydrite/hematite nanocomposites have been measured.

Photoluminescence light-up detection of zinc ion and imaging in living cells based on the aggregation induced emission enhancement of glutathione-capped copper nanoclusters.

Science.gov (United States)

Lin, Liyun; Hu, Yuefang; Zhang, Liangliang; Huang, Yong; Zhao, Shulin

2017-08-15

In this work, we prepared glutathione (GSH)-capped copper nanoclusters (Cu NCs) with red emission by simply adjusting the pH of GSH/Cu 2+ mixture at room temperature. A photoluminescence light-up method for detecting Zn 2+ was then developed based on the aggregation induced emission enhancement of GSH-capped Cu NCs. Zn 2+ could trigger the aggregation of Cu NCs, inducing the enhancement of luminescence and the increase of absolute quantum yield from 1.3% to 6.2%. GSH-capped Cu NCs and the formed aggregates were characterized, and the possible mechanism was also discussed. The prepared GSH-capped Cu NCs exhibited a fast response towards Zn 2+ and a wider detection range from 4.68 to 2240μM. The detection limit (1.17μM) is much lower than that of the World Health Organization permitted in drinking water. Furthermore, taking advantages of the low cytotoxicity, large Stokes shift, red emission and light-up detection mode, we explored the use of the prepared GSH-capped Cu NCs in the imaging of Zn 2+ in living cells. The developed luminescence light-up nanoprobe may hold the potentials for Zn 2+ -related drinking water safety and biological applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Controllable synthesis, magnetic and biocompatible properties of Fe3O4 and α-Fe2O3 nanocrystals

International Nuclear Information System (INIS)

Zhou, Xi; Shi, Yanfeng; Ren, Lei; Bao, Shixiong; Han, Yu; Wu, Shichao; Zhang, Honggang; Zhong, Lubin; Zhang, Qiqing

2012-01-01

Iron oxide nanocrystals (NCs) with a series of well-controlled morphologies (octahedron, rod, wire, cube and plate) and compositions (Fe 3 O 4 and α-Fe 2 O 3 ) were synthesized via a facile hydrothermal process. The morphological and compositional control of various iron oxide NCs was based on the regulations of precursor thermolysis kinetics and surfactants. The obtained samples were characterized by XRD, SEM, TEM, SQUID and cytotoxicity test. These as-prepared iron oxide NCs showed excellent magnetic properties and good biocompatibility, paving the way for their high-efficiency bio-separation and bio-detection applications. - Graphical Abstract: Schematic illustration for the formation of iron oxide NCs (Fe 3 O 4 and α-Fe 2 O 3 ) with different controlled morphologies and compositions. Highlights: ► Iron oxide NCs with a series of well-controlled morphologies (octahedron, rod, wire, cube, and plate) and compositions (Fe 3 O 4 and α-Fe 2 O 3 ) were synthesized via a facile hydrothermal method. ► The mechanism of the morphological and compositional control process is directly related to precursor thermolysis kinetics and surfactants. ► These iron oxide NCs exhibited excellent magnetic response and good biocompatibility, which should have great applications in the cell separation and biodetection.

Immune cell impact of three differently coated lipid nanocapsules: pluronic, chitosan and polyethylene glycol.

Science.gov (United States)

Farace, Cristiano; Sánchez-Moreno, Paola; Orecchioni, Marco; Manetti, Roberto; Sgarrella, Francesco; Asara, Yolande; Peula-García, José M; Marchal, Juan A; Madeddu, Roberto; Delogu, Lucia G

2016-01-05

Lipid nanocapsules (NCs) represent promising tools in clinical practice for diagnosis and therapy applications. However, the NC appropriate functionalization is essential to guarantee high biocompatibility and molecule loading ability. In any medical application, the immune system-impact of differently functionalized NCs still remains to be fully understood. A comprehensive study on the action exerted on human peripheral blood mononuclear cells (PBMCs) and major immune subpopulations by three different NC coatings: pluronic, chitosan and polyethylene glycol-polylactic acid (PEG) is reported. After a deep particle characterization, the uptake was assessed by flow-cytometry and confocal microscopy, focusing then on apoptosis, necrosis and proliferation impact in T cells and monocytes. Cell functionality by cell diameter variations, different activation marker analysis and cytokine assays were performed. We demonstrated that the NCs impact on the immune cell response is strongly correlated to their coating. Pluronic-NCs were able to induce immunomodulation of innate immunity inducing monocyte activations. Immunomodulation was observed in monocytes and T lymphocytes treated with Chitosan-NCs. Conversely, PEG-NCs were completely inert. These findings are of particular value towards a pre-selection of specific NC coatings depending on biomedical purposes for pre-clinical investigations; i.e. the immune-specific action of particular NC coating can be excellent for immunotherapy applications.

Diagnostic characterization of services providing care to victims of accidents and violence in five Brazilian state capitals

Directory of Open Access Journals (Sweden)

Suely Ferreira Deslandes

2006-06-01

Full Text Available This article characterizes the services providing care to victims in five Brazilian regions with high violence and accident rates. It analyzes care activities and strategies, the profile of the teams, the conditions of installations, equipment and supplies, integrated care and registration services and the opinion of health managers with respect to the needs and requirements for a better care to the victims. The sample is composed by 103 services: 34 from Recife, 25 from Rio de Janeiro, 18 from Manaus, 18 from Curitiba and 8 from Brasília. The still preliminary results indicate: lower number of services focusing on the elderly; scarce investment in preventive actions; the principal actions carried out are social assistance, ambulatory and hospital care and psychological assistance; patients received from Basic Health Units require attention of the communities and families; need for investment in capacity building programs for professionals; precarious registries, data handled manually. The wording of the National Policy for Reduction of Morbidity and Mortality from Accidents and Violence is not well-known and there is a lack of articulation among and inside sectors and between prehospital and emergency care services. Rehabilitation services are insufficient in all cities.

Current and future industrial energy service characterizations

Energy Technology Data Exchange (ETDEWEB)

Krawiec, F.; Thomas, T.; Jackson, F.; Limaye, D.R.; Isser, S.; Karnofsky, K.; Davis, T.D.

1980-10-01

Current and future energy demands, end uses, and cost used to characterize typical applications and resultant services in the industrial sector of the United States and 15 selected states are examined. A review and evaluation of existing industrial energy data bases was undertaken to assess their potential for supporting SERI research on: (1) market suitability analysis, (2) market development, (3) end-use matching, (3) industrial applications case studies, and (4) identification of cost and performance goals for solar systems and typical information requirements for industrial energy end use. In reviewing existing industrial energy data bases, the level of detail, disaggregation, and primary sources of information were examined. The focus was on fuels and electric energy used for heat and power purchased by the manufacturing subsector and listed by 2-, 3-, and 4-digit SIC, primary fuel, and end use. Projections of state level energy prices to 1990 are developed using the energy intensity approach. The effects of federal and state industrial energy conservation programs on future industrial sector demands were assessed. Future end-use energy requirements were developed for each 4-digit SIC industry and were grouped as follows: (1) hot water, (2) steam (212 to 300/sup 0/F, each 100/sup 0/F interval from 300 to 1000/sup 0/F, and greater than 1000/sup 0/F), and (3) hot air (100/sup 0/F intervals). Volume I details the activities performed in this effort.

Characterization of the industrial irradiation services operating in the state of Rio de Janeiro

International Nuclear Information System (INIS)

Oliveira, J.S.; Campos, I.C.; Silva, J F.; Gomes, A.S.

2017-01-01

Industrial irradiation is the practice that, making use of electron beams or gamma rays, provides benefits such as sterilization of hospital products, food preservation, treatment of precious stones, the aging of cachaça and the preservation of works of art. The objective of the work is to characterize the overview of industrial irradiation services operating in the state of Rio de Janeiro (RJ). The methodology involved a survey of the installations licensed by the Brazilian National Nuclear Energy Commission (CNEN) for the industrial irradiation operation in the state. Technical visits were organized at the Radiological Protection Services of all detected facilities. It was found that there are only two installations authorized by CNEN in RJ and both use electron beam irradiation. Only one of them acts with the commercialization of the service, employing a 10-mega electron-volt double beam from two linear particle accelerators. The second facility uses the service for its own purposes, equipped with a single accelerator, single-beam 600-kilo electron-volt emitter. It is concluded that, numerically, there are few industrial irradiation facilities in RJ. Based on characteristics such as beam penetrability, the nature of the source, logistic cost and radiation protection measures, these facilities prefer to make use of accelerators (electron beams). It should be noted that if the only company that currently offers the service to third parties decides to close its activities, manufacturers, suppliers, and consequently the population can suffer some impact, given the absence of options in the market

Ultrastable BSA-capped gold nanoclusters with a polymer-like shielding layer against reactive oxygen species in living cells

Science.gov (United States)

Zhou, Wenjuan; Cao, Yuqing; Sui, Dandan; Guan, Weijiang; Lu, Chao; Xie, Jianping

2016-05-01

The prevalence of reactive oxygen species (ROS) production and the enzyme-containing intracellular environment could lead to the fluorescence quenching of bovine serum albumin (BSA)-capped gold nanoclusters (AuNCs). Here we report an efficient strategy to address this issue, where a polymer-like shielding layer is designed to wrap around the Au core to significantly improve the stability of AuNCs against ROS and protease degradation. The key of our design is to covalently incorporate a thiolated AuNC into the BSA-AuNC via carbodiimide-activated coupling, leading to the formation of a AuNC pair inside the cross-linked BSA molecule. The as-designed paired AuNCs in BSA (or BSA-p-AuNCs for short) show improved performances in living cells.The prevalence of reactive oxygen species (ROS) production and the enzyme-containing intracellular environment could lead to the fluorescence quenching of bovine serum albumin (BSA)-capped gold nanoclusters (AuNCs). Here we report an efficient strategy to address this issue, where a polymer-like shielding layer is designed to wrap around the Au core to significantly improve the stability of AuNCs against ROS and protease degradation. The key of our design is to covalently incorporate a thiolated AuNC into the BSA-AuNC via carbodiimide-activated coupling, leading to the formation of a AuNC pair inside the cross-linked BSA molecule. The as-designed paired AuNCs in BSA (or BSA-p-AuNCs for short) show improved performances in living cells. Electronic supplementary information (ESI) available: Detailed experimental materials, apparatus, experimental procedures and characterization data. See DOI: 10.1039/c6nr02178f

Characterization and energy potential of food waste from catering service in Hangzhou, China.

Science.gov (United States)

Guo, Xiao-Hui; Sun, Fa-Qian; Sun, Ying-Jun; Lu, Hao-Hao; Wu, Wei-Xiang

2014-08-01

Safe disposal of food waste is becoming an impending issue in China with the rapid increase of its production and the promotion of environmental awareness. Food waste from catering services in Hangzhou, China, was surveyed and characterized in this study. A questionnaire survey involving 632 units across the urban districts showed that 83.5% of the food waste was not properly treated. Daily food waste production from catering units was estimated to be 1184.5 tonnes. The ratio of volatile solid to total solid, easily biodegradable matter (including crude fat, crude protein and total starch) content in total solid and the ratio of total organic carbon to nitrogen varied in ranges of 90.1%-93.9%, 60.9%-72.1%, and 11.9-19.9, respectively. Based on the methane yield of 350 mL g VS(-1) in anaerobic batch tests, annual biogas energy of 1.0 × 10(9) MJ was estimated to be recovered from the food waste. Food waste from catering services was suggested to be an attractive clean energy source by anaerobic digestion. © The Author(s) 2014.

Toddlers - Background & Validation Studies - NCS Dietary Assessment Literature Review

Science.gov (United States)

This stage of development is characterized by the slowing of the growth velocity and a rapid increase in fine and gross motor skills supporting increases in independence, exploration of the environment, and language skills.

Antimicrobial Lemongrass Essential Oil—Copper Ferrite Cellulose Acetate Nanocapsules

Directory of Open Access Journals (Sweden)

Ioannis L. Liakos

2016-04-01

Full Text Available Cellulose acetate (CA nanoparticles were combined with two antimicrobial agents, namely lemongrass (LG essential oil and Cu-ferrite nanoparticles. The preparation method of CA nanocapsules (NCs, with the two antimicrobial agents, was based on the nanoprecipitation method using the solvent/anti-solvent technique. Several physical and chemical analyses were performed to characterize the resulting NCs and to study their formation mechanism. The size of the combined antimicrobial NCs was found to be ca. 220 nm. The presence of Cu-ferrites enhanced the attachment of LG essential oil into the CA matrix. The magnetic properties of the combined construct were weak, due to the shielding of Cu-ferrites from the polymeric matrix, making them available for drug delivery applications where spontaneous magnetization effects should be avoided. The antimicrobial properties of the NCs were significantly enhanced with respect to CA/LG only. This work opens novel routes for the development of organic/inorganic nanoparticles with exceptional antimicrobial activities.

Antimicrobial Lemongrass Essential Oil-Copper Ferrite Cellulose Acetate Nanocapsules.

Science.gov (United States)

Liakos, Ioannis L; Abdellatif, Mohamed H; Innocenti, Claudia; Scarpellini, Alice; Carzino, Riccardo; Brunetti, Virgilio; Marras, Sergio; Brescia, Rosaria; Drago, Filippo; Pompa, Pier Paolo

2016-04-20

Cellulose acetate (CA) nanoparticles were combined with two antimicrobial agents, namely lemongrass (LG) essential oil and Cu-ferrite nanoparticles. The preparation method of CA nanocapsules (NCs), with the two antimicrobial agents, was based on the nanoprecipitation method using the solvent/anti-solvent technique. Several physical and chemical analyses were performed to characterize the resulting NCs and to study their formation mechanism. The size of the combined antimicrobial NCs was found to be ca. 220 nm. The presence of Cu-ferrites enhanced the attachment of LG essential oil into the CA matrix. The magnetic properties of the combined construct were weak, due to the shielding of Cu-ferrites from the polymeric matrix, making them available for drug delivery applications where spontaneous magnetization effects should be avoided. The antimicrobial properties of the NCs were significantly enhanced with respect to CA/LG only. This work opens novel routes for the development of organic/inorganic nanoparticles with exceptional antimicrobial activities.

Origin of the Substitution Mechanism for the Binding of Organic Ligands on the Surface of CsPbBr3 Perovskite Nanocubes.

Science.gov (United States)

Ravi, Vikash Kumar; Santra, Pralay K; Joshi, Niharika; Chugh, Jeetender; Singh, Sachin Kumar; Rensmo, Håkan; Ghosh, Prasenjit; Nag, Angshuman

2017-10-19

Optoelectronic properties of CsPbBr 3 perovskite nanocubes (NCs) depend strongly on the interaction of the organic passivating molecules with the inorganic crystal. To understand this interaction, we employed a combination of synchrotron-based X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance (NMR) spectroscopy, and first-principles density functional theory (DFT)-based calculations. Variable energy XPS elucidated the internal structure of the inorganic part in a layer-by-layer fashion, whereas NMR characterized the organic ligands. Our experimental results confirm that oleylammonium ions act as capping ligands by substituting Cs + ions from the surface of CsPbBr 3 NCs. DFT calculations shows that the substitution mechanism does not require much energy for surface reconstruction and, in contrast, stabilizes the nanocrystal by the formation of three hydrogen bonds between the -NH 3 + moiety of oleylammonium and surrounding Br - on the surface of NCs. This substitution mechanism and its origin are in stark contrast to the usual adsorption of organic ligands on the surface of typical NCs.

Post-traumatic stress disorder, drug abuse and migraine: new findings from the National Comorbidity Survey Replication (NCS-R).

Science.gov (United States)

Peterlin, B Lee; Rosso, Andrea L; Sheftell, Fred D; Libon, David J; Mossey, Jana M; Merikangas, Kathleen R

2011-01-01

Post-traumatic stress disorder (PTSD) has been shown to be associated with migraine and drug abuse. This was an analysis of data from the National Comorbidity Survey Replication (NCS-R) to evaluate the association of PTSD in those with episodic migraine (EM) and chronic daily headache (CDH). Our sample consisted of 5,692 participants. Lifetime and 12-month prevalence rates of PTSD were increased in those with EM and CDH. After adjustments, the lifetime odds ratio (OR) of PTSD was greater in those with EM (OR 3.07 confidence interval [CI]: 2.12, 4.46) compared to those without headache; was greater in men than women with EM (men: OR 6.86; CI: 3.11, 15.11; women: OR 2.77; CI: 1.83, 4.21); and was comparable or greater than the association between migraine with depression or anxiety. The lifetime OR of PTSD was also increased in CDH sufferers. The OR of illicit drug abuse was not increased in those with EM or CDH unless co-occurring with PTSD or depression. The lifetime and 12-month OR of PTSD is increased in those with migraine or CDH, and is greater in men than women with migraine. The lifetime and 12-month OR of illicit drug abuse is not increased in those with migraine or CDH unless co-occurring with PTSD or depression.

Tuning of gold nanoclusters sensing applications with bovine serum albumin and bromelain for detection of Hg2+ ion and lambda-cyhalothrin via fluorescence turn-off and on mechanisms.

Science.gov (United States)

Bhamore, Jigna R; Jha, Sanjay; Basu, Hirakendu; Singhal, Rakesh Kumar; Murthy, Z V P; Kailasa, Suresh Kumar

2018-04-01

Herein, fluorescent gold nanoclusters (Au NCs) were obtained by one-pot synthetic method using bovine serum albumin (BSA) and bromelain as templates. As-synthesized fluorescent Au NCs were stable and showed bright red fluorescence under UV lamp at 365 nm. The fluorescent Au NCs exhibit the emission intensity at 648 nm when excited at 498 nm. Various techniques were used such as spectroscopy (UV-visible, fluorescence, and Fourier-transform infrared), high-resolution transmission electron microscopy, and dynamic light scattering for the characterization of fluorescent Au NCs. The values of I 0 /I at 648 nm are proportional to the concentrations of Hg 2+ ion in the range from 0.00075 to 5.0 μM and of lambda-cyhalothrin in the range from 0.01 to 10 μM with detection limits of 0.0003 and 0.0075 μM for Hg 2+ ion and lambda-cyhalothrin, respectively. The practical application of the probe was successfully demonstrated by analyzing Hg 2+ ion and lambda-cyhalothrin in water samples. In addition, Au NCs used as probes for imaging of Simplicillium fungal cells. These results indicated that the as-synthesized Au NCs have proven to be promising fluorescent material for the sensing of Hg 2+ ion and lambda-cyhalothrin in environmental and for imaging of microorganism cells in biomedical applications.

Applying low-energy multipulse excimer laser annealing to improve charge retention of Au nanocrystals embedded MOS capacitors

International Nuclear Information System (INIS)

Shen, Kuan-Yuan; Chen, Hung-Ming; Liao, Ting-Wei; Kuan, Chieh-Hsiung

2015-01-01

The low-energy multipulse excimer laser annealing (LEM-ELA) is proposed to anneal the nanostructure of nanocrystal (NC) embedded in a SiO 2 thin film without causing atomic diffusion and damaging the NCs, since the LEM-ELA combining the advantages of laser annealing and UV curing features rapid heating and increasing oxide network connectivity. A Fourier transform infrared spectroscopy (FTIR) characterization of SiO 2 thin films annealed using LEM-ELA indicated that the quality was improved through the removal of water-related impurities and the reconstruction of the network Si–O–Si bonds. Then, LEM-ELA was applied to a SiO 2 thin film embedded with Au NCs, which were fabricated as MOS capacitors. The charge retention was greatly improved and the percentage of retained charges was about 10% after 3  ×  10 8  s. To investigate and differentiate the effects of LEM-ELA on charges stored in both oxide traps and in the Au NCs, a double-mechanism charge relaxation analysis was performed. The results indicated that the oxide traps were removed and the confinement ability of Au NCs was enhanced. The separated memory windows contributed from the charges in Au NCs and those in oxide traps were obtained and further confirmed that the LEM-ELA removed oxide traps without damaging the Au NCs. (paper)

Non-injection and one-pot approach to CdSe: Eu3+ hybrid nanocrystals with tunable photoluminescence from green to red

International Nuclear Information System (INIS)

Kong, Lingcan; Chu, Xuefeng; Wang, Chuanxi; Yang, Xiaotian; Zhou, Lei

2017-01-01

Europium ion-doped CdSe hybrid nanocrystals (CdSe:Eu 3+ NCs) as a class of new luminescent materials have drawn increasing attention in recent years owing to their remarkable optical properties. In this paper, we report a facile method to prepare CdSe:Eu 3+ NCs using oleic acid (OA) as the capping agent. With this non-injection and one-pot synthesized approach, the formation and surface passivation of CdSe:Eu 3+ NCs are performed simultaneously and result in intrinsic luminescence. The as-prepared CdSe:Eu 3+ NCs are characterized by transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy (EDX). Their optical properties are also studied by UV–vis and photoluminescence spectra. Moreover, the effects of feed ratios and reaction temperatures on the optical properties are further investigated. The results show that the luminescent spectra of CdSe:Eu 3+ NCs are tunable from green (490 nm) to red (630 nm) and gradually redshift with the increase of the nanoparticle size from 2.5 to 4.4 nm. Upon decoration with 2-thenoyltrifluoroacetone (TTA), the luminescence of europium ion drastically increases and efficient energy transfer from CdSe host to the europium ion is proposed. In addition, an MTT and apoptosis assay show CdSe:Eu 3+ NCs have low cellular toxicity and could be used as fluorescence imaging for human epithelial type 2 (Hep-2) cells. These properties make CdSe:Eu 3+ NCs a potential candidate for biological labeling, immunoassays, and optical sensing.

Numb chin syndrome: A reflection of malignancy or a harbinger of MRONJ? A multicenter experience.

Science.gov (United States)

Fortunato, Leonzio; Amato, Massimo; Simeone, Michele; Bennardo, Francesco; Barone, Selene; Giudice, Amerigo

2018-04-20

Numb chin syndrome (NCS) or mental neuropathy (MN) is a disorder characterized by sensory neuropathy on the distribution of the inferior alveolar nerve or mental nerve. The most frequent causes are of odontogenic origin (infections, wrong therapies). Other etiologies are related to primary tumor, metastasis, osteoradionecrosis and medication-related osteonecrosis of the jaw (MRONJ). The aim of this study is to highlight the clinical importance of NCS as one of the first symptoms of cancer or as consequence of drug therapy. The present study was conducted from 2010 to 2016 by recruiting patients who present NCS as one of the symptoms, having excluded those in which it depends on a clear odontogenic cause, on systemic degenerative diseases or metabolic disorders. Data collection included suspected diagnosis at the time of presentation of the symptom, final diagnosis, mandibular localization, treatment performed and diagnostic delay between the first medical examination and the definitive diagnosis. This study included 29 patients in which NCS had not a clear odontogenic cause. NCS was the first symptom of malignancy in 11 cases and the clinical sign of metastasis in 4 cases. In a single patient, it was the first symptom of an immune-mediated disease. In the remaining 13 patients, NCS represented the symptom of MRONJ. NCS can be the first symptom of malignancy, especially in patients with a previous history of cancer, but also a prodromal sign of MRONJ. It should be recognized in order to require deeper examinations for early diagnosis of the disease. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Non-injection and one-pot approach to CdSe: Eu{sup 3+} hybrid nanocrystals with tunable photoluminescence from green to red

Energy Technology Data Exchange (ETDEWEB)

Kong, Lingcan, E-mail: konglingcan2010@163.com [Wuxi Center for Disease Control and Prevention (China); Chu, Xuefeng [Jilin Jianzhu University, Jilin Provincial Key Laboratory of Architectural Electricity & Comprehensive Energy Saving, School of Electrical and Electronic Information Engineering (China); Wang, Chuanxi, E-mail: wangcx@jiangnan.edu.cn [Jiangnan University, China-Australia Joint Research Centre for Functional Molecular Materials, School of Chemical & Material Engineering (China); Yang, Xiaotian [Jilin Jianzhu University, Jilin Provincial Key Laboratory of Architectural Electricity & Comprehensive Energy Saving, School of Electrical and Electronic Information Engineering (China); Zhou, Lei [Wuxi Center for Disease Control and Prevention (China)

2017-01-15

Europium ion-doped CdSe hybrid nanocrystals (CdSe:Eu{sup 3+} NCs) as a class of new luminescent materials have drawn increasing attention in recent years owing to their remarkable optical properties. In this paper, we report a facile method to prepare CdSe:Eu{sup 3+} NCs using oleic acid (OA) as the capping agent. With this non-injection and one-pot synthesized approach, the formation and surface passivation of CdSe:Eu{sup 3+} NCs are performed simultaneously and result in intrinsic luminescence. The as-prepared CdSe:Eu{sup 3+} NCs are characterized by transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy (EDX). Their optical properties are also studied by UV–vis and photoluminescence spectra. Moreover, the effects of feed ratios and reaction temperatures on the optical properties are further investigated. The results show that the luminescent spectra of CdSe:Eu{sup 3+} NCs are tunable from green (490 nm) to red (630 nm) and gradually redshift with the increase of the nanoparticle size from 2.5 to 4.4 nm. Upon decoration with 2-thenoyltrifluoroacetone (TTA), the luminescence of europium ion drastically increases and efficient energy transfer from CdSe host to the europium ion is proposed. In addition, an MTT and apoptosis assay show CdSe:Eu{sup 3+} NCs have low cellular toxicity and could be used as fluorescence imaging for human epithelial type 2 (Hep-2) cells. These properties make CdSe:Eu{sup 3+} NCs a potential candidate for biological labeling, immunoassays, and optical sensing.

Service Provisioning Framework for Digital Smart Home Services

OpenAIRE

Kazanavicius , Egidijus; Imbrasas , Darius; Razukas , Mantas

2011-01-01

Part 3: Digital Goods and Products; International audience; “Development and Management Framework of Smart Home Services (SNAPAS)” is an innovative system, which seeks to fill the market niche of Smart Home services and fully complies with the priorities of scientific development approved by the European Parliament and Council. Framework is characterized by an open component-based pluggable architecture, which provides new forms of interactive services in home environments, including the thir...

Numb Chin Syndrome Leading to a Diagnosis of Salivary Ductal Adenocarcinoma: A Case Report and Review of the Literature

Directory of Open Access Journals (Sweden)

Lei Wu

2017-07-01

Full Text Available Numb chin syndrome (NCS refers to a rare sensory neuropathy characterized by numbness of the chin within the distribution of the mental or inferior alveolar nerve. Although NCS is usually caused by a benign process, it should not be underestimated and a thorough diagnostic evaluation for a new or known progressive malignancy should always be performed. Here, we report a case of salivary ductal adenocarcinoma that mimicked a pulpitis and periodontitis in its early presentation accompanied by numbness of chin. The course and diagnosis of this case are discussed, and a brief review of the literature is presented. It is hoped for clinicians to keep the malignant possibility of NCS in mind and take a thorough examination.

Synthesis and characterization of 2,3,13,14-tetramethyl (ethyl or p-tolyl-1,4,12,15-tetraazacyclodocosa-1,3,12,14-tetraene complexes of Mg(II, Ca(II, Sr(II and Ba(II

Directory of Open Access Journals (Sweden)

SEEMA GUPTA

2002-07-01

Full Text Available 2+2 Cyclocondensation of 1,7-diaminoheptane with a-diketones, viz. 2,3-butanedione, 3,4-hexanedione or 4,4’-dimethylbenzil, in the presence of Mg2+, Ca2+, Sr2+ and Ba2+ ions as templates yields a series of complexes of the type [ML(X2] (where L = N4 macrocycle having a 22-membered ring and X = Cl or NCS. The resulting complexes were characterized by elemental analysis, conductance measurements and IR and 1H-NMR spectral studies.

Synthesis of highly dispersed Pt nanoclusters anchored graphene composites and their application for non-enzymatic glucose sensing

International Nuclear Information System (INIS)

Chang, Gang; Shu, Honghui; Huang, Qiwei; Oyama, Munetaka; Ji, Kai; Liu, Xiong; He, Yunbin

2015-01-01

Highlights: • PtNCs/graphene (PVP) composites were obtained by a clean and facile method. • The addition of graphene effectively promotes the catalytic performance of composites. • The highly dispersed PtNCs show superior electrocatalytic activity to glucose oxidation. • PtNCs/graphene (PVP) composites exhibit excellent stability and selectivity for nonenzymatic glucose detection. - Abstract: A facile and clean method by using ascorbic acid as mild reductant was developed to synthesize nanocomposites of graphene and platinum nanoclusters (PtNCs/graphene), in which Polyvinyl-Pyrrolidone (PVP) was added during the one-step reductive process so as to improve the dispersity of PtNCs on the graphene and decrease the size of PtNCs. By several characterization methods such as X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), we demonstrated that Pt nanoclusters have successfully anchored on the surface of graphene sheets with average diameter of 22 nm. It was found that with the assistant of PVP, Pt nanoclusters appeared with smaller particle size and narrower particle size distribution. Cyclic voltammetry and amperometric methods were used to evaluate the electro-catalytic activity of the synthesized nanocomposites toward the oxidation of glucose in neutral media (0.1 M PBS, pH 7.4). The PtNCs/graphene exhibited a rapid response time (about 3 s), a broad linear range (1 mM to 25 mM), good stability, and sensitivity estimated to be 1.21 μA cm −2 mM −1 (R = 0.995, 71.9 μA cm −2 mM −1 vs. geometric area). Additionally, the impact from the oxidation of interferences can be effectively limited by choosing the appropriate detection potential. These results indicated a great potential of PtNCs/graphene in fabricating novel non-enzymatic glucose sensors with high performance

Health risk characterization for exposure to benzene in service stations and petroleum refineries environments using human adverse response data.

Science.gov (United States)

Edokpolo, Benjamin; Yu, Qiming Jimmy; Connell, Des

2015-01-01

Health risk characterization of exposure to benzene in service stations and petroleum refineries has been carried out in previous studies using guideline values set by various agencies. In this work, health risk was characterized with the exposure data as cumulative probability distribution (CPD) plots but using human epidemiological data. This was achieved by using lowest observable adverse effects levels (LOAEL) data plotted as cumulative probability lowest effects distribution (CPLED). The health risk due to benzene was characterized by using probabilistic methods of hazard quotient (HQ 50/50 and HQ 95/5 ), Monte-Carlo simulation (MCS) and overall risk probability (ORP). CPD relationships of adverse health effects relationships and exposure data were in terms of average daily dose (ADD) and lifetime average daily dose (LADD) for benzene. For service station environments HQ 50/50 and HQ 95/5 were in a range of 0.000071-0.055 and 0.0049-21, respectively. On the other hand, the risk estimated for petroleum refinery environments suggests higher risk with HQ 50/50 and HQ 95/5 values ranging from 0.0012 to 77 and 0.17 to 560, respectively. The results of Monte-Carlo risk probability (MRP) and ORP indicated that workers in petroleum refineries (MRP of 2.9-56% and ORP of 4.6-52% of the affected population) were at a higher risk of adverse health effects from exposure to benzene as compared to exposure to benzene in service station environments (MRP of 0.051 -3.4% and ORP of 0.35-2.7% affected population). The adverse effect risk probabilities estimated by using the Monte-Carlo simulation technique and the ORP method were found to be generally consistent.

Incorporation of Cu{sub 2}O nanocrystals into TiO{sub 2} photonic crystal for enhanced UV–visible light driven photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Geng, Zhi; Zhang, Yu; Yuan, Xing; Huo, Mingxin; Zhao, Yahui; Lu, Ying, E-mail: luy332@nenu.edu.cn; Qiu, Yue

2015-09-25

Highlights: • The Cu{sub 2}O NCs/TiO{sub 2} PC composite was synthesized and exhibited high photocatalysis. • The improved light harvesting and increased quantum yield was achieved. • The hydroxyl radical was the primary oxidant in Cu{sub 2}O NCs/TiO{sub 2} PC photocatalysis. - Abstract: A 3D UV–visible light responsive photocatalyst was fabricated by infiltrating Cu{sub 2}O nanocrystals (NCs) into TiO{sub 2} photonic crystal (PC). Morphology characterization presented that Cu{sub 2}O NCs with average diameter around 10 nm were dispersed uniformly into TiO{sub 2} PC. The transmittance spectra showed that Cu{sub 2}O NCs/TiO{sub 2} 260, prepared by integrating Cu{sub 2}O NCs with TiO{sub 2} 260 which was fabricated from 260 nm polystyrene spheres, exhibited the highest light harvesting. The photoluminescence spectra confirmed the electron/hole pairs recombination of Cu{sub 2}O NCs/TiO{sub 2} 260 was efficiently inhibited due to the unique heterojunction structure between TiO{sub 2} and Cu{sub 2}O. In the photocatalytic degradation of Rhodamine B and Bisphenol A under UV–visible light (320 nm < λ < 780 nm) irradiation, the kinetic constant using Cu{sub 2}O NCs/TiO{sub 2} 260 was 3.99 and 8.37-fold larger than that using TiO{sub 2} nanoparticle (NP), respectively. The enhanced photocatalysis benefited from the increased light harvesting owing to the excitation of both TiO{sub 2} and Cu{sub 2}O NCs whose optical absorption was intensified by the photonic effect of TiO{sub 2} 260 and the high quantum efficiency due to the Cu{sub 2}O/TiO{sub 2} heterojunction. The hydroxyl radical, generated from the protonation of superoxide radical which was derived from the reduction of oxygen by photogenerated electrons, was the main oxidant responsible for pollutant degradation.

Unveiling the Shape Evolution and Halide-Ion-Segregation in Blue-Emitting Formamidinium Lead Halide Perovskite Nanocrystals Using an Automated Microfluidic Platform.

Science.gov (United States)

Lignos, Ioannis; Protesescu, Loredana; Emiroglu, Dilara Börte; Maceiczyk, Richard; Schneider, Simon; Kovalenko, Maksym V; deMello, Andrew J

2018-02-14

Hybrid organic-inorganic perovskites and in particular formamidinium lead halide (FAPbX 3 , X = Cl, Br, I) perovskite nanocrystals (NCs) have shown great promise for their implementation in optoelectronic devices. Specifically, the Br and I counterparts have shown unprecedented photoluminescence properties, including precise wavelength tuning (530-790 nm), narrow emission linewidths (photoluminescence quantum yields (70-90%). However, the controlled formation of blue emitting FAPb(Cl 1-x Br x ) 3 NCs lags behind their green and red counterparts and the mechanism of their formation remains unclear. Herein, we report the formation of FAPb(Cl 1-x Br x ) 3 NCs with stable emission between 440 and 520 nm in a fully automated droplet-based microfluidic reactor and subsequent reaction upscaling in conventional laboratory glassware. The thorough parametric screening allows for the elucidation of parametric zones (FA-to-Pb and Br-to-Cl molar ratios, temperature, and excess oleic acid) for the formation of nanoplatelets and/or NCs. In contrast to CsPb(Cl 1-x Br x ) 3 NCs, based on online parametric screening and offline structural characterization, we demonstrate that the controlled synthesis of Cl-rich perovskites (above 60 at% Cl) with stable emission remains a challenge due to fast segregation of halide ions.

Poly(methyl methacrylate) nanocomposites based on TiO{sub 2} nanocrystals: Tailoring material properties towards sensing

Energy Technology Data Exchange (ETDEWEB)

Convertino, A., E-mail: annalisa.convertino@ismn.cnr.i [ISMN-CNR Istituto per lo Studio dei Materiali Nanostrutturati, Via Salaria km. 29.300, 00016 Roma (Italy); Tamborra, M., E-mail: m.tamborra@ba.ipcf.cnr.i [IPCF-CNR Istituto per i Processi Chimici e Fisici, Bari Division, Via Orabona 4, 70126 Bari (Italy); Striccoli, M., E-mail: m.striccoli@ba.ipcf.cnr.i [IPCF-CNR Istituto per i Processi Chimici e Fisici, Bari Division, Via Orabona 4, 70126 Bari (Italy); Leo, G., E-mail: gabriella.leo@ismn.cnr.i [ISMN-CNR Istituto per lo Studio dei Materiali Nanostrutturati, Via Salaria km. 29.300, 00016 Roma (Italy); Agostiano, A., E-mail: a.agostiano@ba.ipcf.cnr.i [IPCF-CNR Istituto per i Processi Chimici e Fisici, Bari Division, Via Orabona 4, 70126 Bari (Italy); Dipartimento di Chimica., Universita di Bari, Via Orabona 4, 70126 Bari (Italy); Curri, M.L., E-mail: lucia.curri@ba.ipcf.cnr.i [IPCF-CNR Istituto per i Processi Chimici e Fisici, Bari Division, Via Orabona 4, 70126 Bari (Italy)

2011-03-31

Nanocomposite materials have been obtained by dispersing organic capped TiO{sub 2} nanocrystals (NCs) with different shape and surface chemistry in poly(methyl methacrylate) (PMMA) as a host medium. Films of the prepared nanocomposites based on TiO{sub 2} NCs have been fabricated by spin coating and morphologically characterized as a function of the preparative conditions. The organic vapor absorption ability of the PMMA/TiO{sub 2} NC based nanocomposites has been then investigated both for spherical and rod-like NCs, and the chemical nature of the coordinating organic molecules has been also varied. The results of the investigation have demonstrated that NC geometry and surface chemistry can modulate the specific absorption characteristics of the modified PMMA in order to absorb different solvent molecules (i.e. acetone, ethanol, propan-2-ol and water). Such features, due to specific interactions between the potential analyte vapors and the functionalized surface of NCs, can effectively be addressed in a controlled and reproducible way, thus offering original opportunities for designing innovative chemical sensors.

Ag nanodots decorated SiO2 coated ZnO core-shell nanostructure with enhanced luminescence property as potential imaging agent

Science.gov (United States)

Gupta, Jagriti; Barick, K. C.; Hassan, P. A.; Bahadur, Dhirendra

2018-04-01

Ag decorated silica coated ZnO nanocomposite (Ag@SiO2@ZnO NCs) has been synthesized by soft chemical approach. The physico-chemical properties of Ag@SiO2@ZnO NCs are investigated by various sophisticated characterization techniques such as X-ray diffraction, Transmission electron microscopy, X-ray photoelectron spectroscopy, UV-visible absorption and photoluminescent spectroscopy. X-ray diffraction confirms the phase formation of ZnO and Ag in nanocomposite. TEM micrograph clearly shows that Ag nanodots are well decorated over silica coated ZnO NCs. The photoluminescent study reveals the enhancement in the photoluminance property when the Ag nanodots are decorated over silica coated ZnO nanocomposite due to an electromagnetic coupling between excitons and plasmons. Furthermore, the photoluminescent property is an important tool for bio-imaging application, reveal that NCs give green and red emission after excitation with 488 and 535 nm. Therefore, low cytotoxicity and excellent fluorescence stability in vitro makes it a more suitable material for both cellular imaging and therapy for biomedical applications.

Comparison of in situ polymerization and solution-dispersion techniques in the preparation of Polyimide/Montmorillonite (MMT) Nanocomposites.

Science.gov (United States)

Ahmad, Mansor Bin; Gharayebi, Yadollah; Salit, Mohd Sapuan; Hussein, Mohd Zobir; Shameli, Kamyar

2011-01-01

In this paper, Polyimide/Montmorillonite Nanocomposites (PI/MMT NCs), based on aromatic diamine (4-Aminophenyl sulfone) (APS) and aromatic dianhydride (3,3',4,4'-benzophenonetetracarboxylic dianhydride) (BTDA) were prepared using in situ polymerization and solution-dispersion techniques. The prepared PI/MMT NCs films were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA). The XRD results showed that at the content of 1.0 wt % Organo Montmorillonite (OMMT) for two techniques and 3.0 wt % OMMT for the in situ polymerization technique, the OMMT was well-intercalated, exfoliated and dispersed into polyimide matrix. The OMMT agglomerated when its amount exceeded 10 wt % and 3.0 wt % for solution-dispersion and in situ polymerization techniques respectively. These results were confirmed by the TEM images of the prepared PI/MMT NCs. The TGA thermograms indicated that thermal stability of prepared PI/MMT NCs were increased with the increase of loading that, the effect is higher for the samples prepared by in situ polymerization technique.

Non-covalent attachment of silver nanoclusters onto single-walled carbon nanotubes with human serum albumin as linking molecule

Energy Technology Data Exchange (ETDEWEB)

Rodríguez-Galván, Andrés, E-mail: andres.rodriguez@nucleares.unam.mx [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510 México D.F. (Mexico); Instituto de Física, Dpto. Física Experimental, Universidad Nacional Autónoma de México, Coyoacán, México, DF 04510 (Mexico); Unidad de Investigación Biomédica en Cáncer INCan-UNAM, Instituto Nacional de Cancerología, México, DF 14080 (Mexico); Heredia, Alejandro [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Circuito Exterior C.U., 04510 México D.F. (Mexico); Amelines-Sarria, Oscar; Rivera, Margarita [Instituto de Física, Dpto. Materia Condensada, Universidad Nacional Autónoma de México, Coyoacán, 04510 México D.F. (Mexico); and others

2015-03-15

The attachment of silver nanoclusters (AgNCs) onto single-walled carbon nanotubes (SWNTs) for the formation of integrated fluorescence sites has attracted much attention due their potential applications as biological probes and nanovectors in theragnosis. Here, we report the preparation through assembly of fluorescent quasi 1-D nanomaterial based on SWNTs and silver nanoclusters (AgNCs) non-covalently attached to human serum albumin as biological linker. The fluorescent SWNT–AgNCs–HSA conjugates were characterized by atomic force microscopy, high-resolution transmission electron microscopy (HRTEM), high angle annular dark field scanning TEM (HAADF-STEM), fluorescent and UV–vis spectroscopy. The above techniques confirmed that AgNCs were non-covalently attached onto the external surface of SWNTs. In addition, it was observed that the modification did not affect the optical properties of the synthesized AgNCs since the absorption spectra and fluorescence under UV irradiation (λ = 365 nm) remain the same. The effect of the functionalized systems was tested on mammal red blood cells (RBCs) and it was found that their structural integrity was compromised by the conjugates, limiting their biological and medical applications.

Non-covalent attachment of silver nanoclusters onto single-walled carbon nanotubes with human serum albumin as linking molecule

International Nuclear Information System (INIS)

Rodríguez-Galván, Andrés; Heredia, Alejandro; Amelines-Sarria, Oscar; Rivera, Margarita

2015-01-01

The attachment of silver nanoclusters (AgNCs) onto single-walled carbon nanotubes (SWNTs) for the formation of integrated fluorescence sites has attracted much attention due their potential applications as biological probes and nanovectors in theragnosis. Here, we report the preparation through assembly of fluorescent quasi 1-D nanomaterial based on SWNTs and silver nanoclusters (AgNCs) non-covalently attached to human serum albumin as biological linker. The fluorescent SWNT–AgNCs–HSA conjugates were characterized by atomic force microscopy, high-resolution transmission electron microscopy (HRTEM), high angle annular dark field scanning TEM (HAADF-STEM), fluorescent and UV–vis spectroscopy. The above techniques confirmed that AgNCs were non-covalently attached onto the external surface of SWNTs. In addition, it was observed that the modification did not affect the optical properties of the synthesized AgNCs since the absorption spectra and fluorescence under UV irradiation (λ = 365 nm) remain the same. The effect of the functionalized systems was tested on mammal red blood cells (RBCs) and it was found that their structural integrity was compromised by the conjugates, limiting their biological and medical applications

Synthesis and characterization of sulfur-functionalized silica nanocapsules as mercury adsorbents

Science.gov (United States)

Palaniappan, Thenappan; Saman, Norasikin; Mat, Hanapi; Johari, Khairiraihanna

2017-12-01

Sulfur functionalized silica nanocapsules (S-SiNC) was successfully synthesized and characterized as a potential adsorbent for industrial applications. The synthesis of S-SiNC was carried out using the mircoemulsion templating method using cetyltrimethylammonium bromide (CTAB) as cationic surfactant, toluene as co-solvent, ammonia solution as catalyst, and tetraethylorthosilicate (TEOS) as the silica base. The S-SiNC adsorbent was characterized using Transmission Electron Microscope, Fourier Transformed Infra Red spectroscopy and nitrogen adsorption/desorption analysis. The physical and chemical properties of the SiNC changed as a result of the functionalization, hence affecting the extent of Hg(II) adsorption. The S-SiNCs were also tested in mercury ion [Hg(II)] adsorption via batch adsorption process with variation in initial Hg (II) concentration. It was found that there is a significant improvement in Hg(II) adsorption performance after being functionalized with elemental sulfur. The highest Hg(II) adsorption capacity was obtained for S-SiNC (107.875 mg/g), which significantly outperformed the blank SiNC. The experimental data obtained was found to be fitting well to the Langmuir isotherm model (R2= 0.979) compared to Freundlich isotherm model. Thus, the results demonstrated the potential application of sulfur functionalized silica nanocapsules as adsorbent in industrial applications.

Atomically Monodisperse Nickel Nanoclusters as Highly Active Electrocatalysts for Water Oxidation

KAUST Repository

Joya, Khurram

2016-04-08

Achieving water splitting at low overpotential with high oxygen evolution efficiency and stability is important for realizing solar to chemical energy conversion devices. Herein we report the synthesis, characterization and electrochemical evaluation of highly active nickel nanoclusters (Ni NCs) for water oxidation at low overpotential. These atomically precise and monodisperse Ni NCs are characterized by using UV-visible absorption spectroscopy, single crystal X-ray diffraction and mass spectrometry. The molecular formulae of these Ni NCs are found to be Ni4(PET)8 and Ni6(PET)12 and are highly active electrocatalysts for oxygen evolution without any pre-conditioning. Ni4(PET)8 are slightly better catalysts than Ni6(PET)12 and initiate the oxygen evolution at an amazingly low overpotential of ~1.51 V (vs RHE; η ≈ 280 mV). The peak oxygen evolution current density (J) of ~150 mA cm–2 at 2.0 V (vs. RHE) with a Tafel slope of 38 mV dec–1 is observed using Ni4(PET)8. These results are comparable to the state-of-the art RuO2 electrocatalyst, which is highly expensive and rare compared to Ni-based materials. Sustained oxygen generation for several hours with an applied current density of 20 mA cm–2 demonstrates the long-term stability and activity of these Ni NCs towards electrocatalytic water oxidation. This unique approach provides a facile method to prepare cost-effective, nanoscale and highly efficient electrocatalysts for water oxidation.

Studies on 4-[N-(furfural) amino] antipyrine complexes of thorium (IV) and dioxouranium (VI)

International Nuclear Information System (INIS)

Agarwal, R.K.; Arora, Kishore; Dutt, Prashant

1997-01-01

Thorium (IV) and dioxouranium (VI) complexes of Schiff base 4-[N-(furfural) amino] antipyrine (FFAP) derived from furfural and 4-aminoantipyrine having general composition ThX 4 .nL (X = Cl - , Br - , NCS - or NO 3 - , n = 2; x = I - or ClO 4 - n = 3, L = FFAP) and UO 2 X 2. nL (X Br - , I - , NCS - ,NO 3 - or CH 3 COO - , n = 2; X = ClO 4 - n = 3, L = FFAP) have been synthesized and characterized by molecular weight, conductivity, IR spectral and thermoanalytical studies. (author)

Characterization of Complementary and Alternative Medicine-Related Consultations in an Academic Drug Information Service.

Science.gov (United States)

Gregory, Philip J; Jalloh, Mohamed A; Abe, Andrew M; Hu, James; Hein, Darren J

2016-12-01

To characterize requests received through an academic drug information consultation service related to complementary and alternative medicines. A retrospective review and descriptive analysis of drug information consultations was conducted. A total of 195 consultations related to complementary and alternative medicine were evaluated. All consultation requests involved questions about dietary supplements. The most common request types were related to safety and tolerability (39%), effectiveness (38%), and therapeutic use (34%). Sixty-eight percent of the requests were from pharmacists. The most frequent consultation requests from pharmacists were questions related to drug interactions (37%), therapeutic use (37%), or stability/compatibility/storage (34%). Nearly 60% of complementary and alternative medicine-related consultation requests were able to be completely addressed using available resources. Among review sources, Natural Medicines Comprehensive Database, Clinical Pharmacology, Micromedex, and Pharmacist's Letter were the most common resources used to address consultations. Utilization of a drug information service may be a viable option for health care professionals to help answer a complementary and alternative medicine-related question. Additionally, pharmacists and other health care professionals may consider acquiring resources identified to consistently answering these questions. © The Author(s) 2015.

Synthesis and characterization of divalent metal complexes with ligand derived from the reaction of 3-aminopyridine and biacetyl

Directory of Open Access Journals (Sweden)

RAMESH KUMAR

2006-09-01

Full Text Available Divalent cobalt, nickel and copper salts reacted in situ with 3-aminopyridine and biacetyl to form complexes of the type: [M(Ap2biac2X2], where Ap2biac is the ligand and X=Cl, Br, NO3 or NCS. The complexes were analysed and characterized as distorted octahedral by conductance, molecular weight, magnetic, electronic and IR spectral studies. The electronic spectra were interpreted and tentative aassignments made. The infrared spectral studies revealed that two molecules of 3-aminopyridine were joined by molecules of biacetyl through a two carbon atom bridge and that the ligand coordinated through azomethine nitrogen atoms, whereas the pyridine nitrogen does not participate in the coordination. In the far infrared spectra, various metal–ligand vibrations were observed and are discussed.

Synthesis of CdS Nanocrystals with Different Shapes via a Colloidal Method

Energy Technology Data Exchange (ETDEWEB)

Bai, Jie; Liu, Changsong; Niu, Jinzhong; Wang, Hongzhe; Xu, Shasha; Shen, Huaibin; Li, Lin Song [Henan Univ., Henan (China)

2014-02-15

Size- and shape-controlled monodisperse wurtzite structured CdS nanorods have been successfully synthesized using a facile solution-based colloidal method. Depending on the control of injection/growth temperatures and the variation of Cd-to-S molar ratios, the morphology of the CdS nanocrystals (NCs) can be adjusted into bullet-like, rod-like, and dot-like shapes. X-ray diffraction (XRD), transition electron microscopy (TEM), and absorption spectroscopy were used to characterize the structure, morphology, and optical properties of as-synthesized CdS NCs. It was found that uniform CdS nanorods could be successfully synthesized when the injection and growth temperatures were very high (> 360 .deg. C). The aspect ratios of different shaped (bullet-like or rod-like) CdS NCs could be controlled by simply adjusting the molar ratios between Cd and S.

Synthesis of CdS Nanocrystals with Different Shapes via a Colloidal Method

International Nuclear Information System (INIS)

Bai, Jie; Liu, Changsong; Niu, Jinzhong; Wang, Hongzhe; Xu, Shasha; Shen, Huaibin; Li, Lin Song

2014-01-01

Size- and shape-controlled monodisperse wurtzite structured CdS nanorods have been successfully synthesized using a facile solution-based colloidal method. Depending on the control of injection/growth temperatures and the variation of Cd-to-S molar ratios, the morphology of the CdS nanocrystals (NCs) can be adjusted into bullet-like, rod-like, and dot-like shapes. X-ray diffraction (XRD), transition electron microscopy (TEM), and absorption spectroscopy were used to characterize the structure, morphology, and optical properties of as-synthesized CdS NCs. It was found that uniform CdS nanorods could be successfully synthesized when the injection and growth temperatures were very high (> 360 .deg. C). The aspect ratios of different shaped (bullet-like or rod-like) CdS NCs could be controlled by simply adjusting the molar ratios between Cd and S

White emitting CdS quantum dot nanoluminophores hybridized on near-ultraviolet LEDs for high-quality white light generation and tuning

International Nuclear Information System (INIS)

Nizamoglu, Sedat; Mutlugun, Evren; Akyuz, Ozgun; Perkgoz, Nihan Kosku; Demir, Hilmi Volkan; Liebscher, Lydia; Sapra, Sameer; Gaponik, Nikolai; Eychmueller, Alexander

2008-01-01

To generate white light using semiconductor nanocrystal (NC) quantum dots integrated on light emitting diodes (LEDs), multiple hybrid device parameters (emission wavelengths of the NCs and the excitation platform, order of the NCs with different sizes, amount of the different types of NCs, etc) need to be carefully designed and properly implemented. In this study, we introduce and demonstrate white LEDs based on simple device hybridization using only a single type of white emitting CdS quantum dot nanoluminophores on near-ultraviolet LEDs. Here we present their design, synthesis-growth, fabrication and characterization. With these hybrid devices, we achieve high color rendering index (>70), despite using only a single NC type. Furthermore, we conveniently tune their photometric properties including the chromaticity coordinates, correlated color temperature, and color rendering index with the number of hybridized nanoluminophores in a controlled manner

One-step aqueous synthesis of fluorescent copper nanoclusters by direct metal reduction

International Nuclear Information System (INIS)

Fernández-Ujados, Mónica; Trapiella-Alfonso, Laura; Costa-Fernández, José M; Pereiro, Rosario; Sanz-Medel, Alfredo

2013-01-01

A one-step aqueous synthesis of highly fluorescent water-soluble copper nanoclusters (CuNCs) is here described, based on direct reduction of the metal precursor with NaBH 4 in the presence of bidentate ligands (made of lipoic acid anchoring groups, appended with a poly(ethylene glycol) short chain). A complete optical and structural characterization was carried out: the optical emission was centred at 416 nm, with a luminescence quantum yield in water of 3.6% (the highest one reported so far in water for this kind of nanocluster). The structural characterization reveals a homogeneous size distribution (of 2.5 nm diameter) with spherical shape. The CuNCs obtained offer long-term stability (the luminescence emission remained unaltered after more than two months) under a broad range of chemical conditions (e.g. stored at pH 3–12 or even in a high ionic strength medium such as 1 M NaCl) and high photostability, keeping their fluorescence emission intact after more than 2 h of daylight and UV-light exposition. All those advantageous features warrant synthesized CuNCs being promising fluorescent nanoprobes for further developments including (bio)applications. (paper)

The synthesis of Ag/polypyrrole coaxial nanocables via ion adsorption method using different oxidants

Science.gov (United States)

Qiu, Teng; Xie, Huxiao; Zhang, Jiangru; Zahoor, Amad; Li, Xiaoyu

2011-03-01

Ag/polypyrrole (PPy) coaxial nanocables (NCs) were synthesized by an ion adsorption method. In this method, the pre-made Ag nanowires (NWs) were dispersed in the aqueous solution of copper acetate (Cu(Ac)2), and the Cu2+ ions adsorbed onto the surface of Ag NWs can oxidize pyrrole monomers to polymerize into uniform PPy sheath outside Ag NWs after the Cu(Ac)2-treated Ag NWs were re-dispersed in the aqueous solution of pyrrole. The morphology of NCs was characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The relationship between the thickness of polymer sheath and the concentration of Cu(Ac)2 was established. As Cu(Ac)2 which served as the oxidant can also be replaced by AgNO3 in this synthesis, the differences on the structure of polymer sheath caused by different oxidants were studied by surface-enhanced Raman scattering (SERS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Comparing with the characterization results of Ag/PPy NCs synthesized using AgNO3 as the oxidant which indicates the random arrangement of PPy chains at the interface between polymer sheath and Ag NWs, PPy chain oxidized by Cu2+ tends to show a relatively ordered conformation at the interface with the pyrrole rings identically taking the plane vertical to the surface of Ag NWs. In addition, although the main part of the polymer sheath was composed of PPy whatever kind of oxidant was used, the sheath of the NCs oxidized by Cu2+ is typical for the existence of Cu(I)-pyrrole coordinate structures with strong Cu(I)-N bond signal shown in XPS characterization.

The synthesis of Ag/polypyrrole coaxial nanocables via ion adsorption method using different oxidants

International Nuclear Information System (INIS)

Qiu Teng; Xie Huxiao; Zhang Jiangru; Zahoor, Amad; Li Xiaoyu

2011-01-01

Ag/polypyrrole (PPy) coaxial nanocables (NCs) were synthesized by an ion adsorption method. In this method, the pre-made Ag nanowires (NWs) were dispersed in the aqueous solution of copper acetate (Cu(Ac) 2 ), and the Cu 2+ ions adsorbed onto the surface of Ag NWs can oxidize pyrrole monomers to polymerize into uniform PPy sheath outside Ag NWs after the Cu(Ac) 2 -treated Ag NWs were re-dispersed in the aqueous solution of pyrrole. The morphology of NCs was characterized by transmission electron microscope (TEM) and scanning electron microscope (SEM). The relationship between the thickness of polymer sheath and the concentration of Cu(Ac) 2 was established. As Cu(Ac) 2 which served as the oxidant can also be replaced by AgNO 3 in this synthesis, the differences on the structure of polymer sheath caused by different oxidants were studied by surface-enhanced Raman scattering (SERS), high-resolution transmission electron microscope (HR-TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS). Comparing with the characterization results of Ag/PPy NCs synthesized using AgNO 3 as the oxidant which indicates the random arrangement of PPy chains at the interface between polymer sheath and Ag NWs, PPy chain oxidized by Cu 2+ tends to show a relatively ordered conformation at the interface with the pyrrole rings identically taking the plane vertical to the surface of Ag NWs. In addition, although the main part of the polymer sheath was composed of PPy whatever kind of oxidant was used, the sheath of the NCs oxidized by Cu 2+ is typical for the existence of Cu(I)–pyrrole coordinate structures with strong Cu(I)–N bond signal shown in XPS characterization.

[Connotation characterization and evaluation of ecological well-being based on ecosystem service theory.

Science.gov (United States)

Zang, Zheng; Zou, Xin- Qing

2016-04-22

China is advocating ecological civilization construction nowadays. Further researches on the relation between ecosystem service and humanity well-being are full of theoretical and practical significance. Combining related researches, this paper defined the concept and connotation of ecological well-being based on ecosystem service theory. Referencing theory of national economic accounting and relative researches, the evaluation indicators of ecological well-being supply and consumption were established. The quantitative characterization and evaluation method of red line of regional ecological well-being was proposed on the basis of location quotient. Then the evaluation of ecological well-being in mainland China in 2012 was set as an example for empirical research. The results showed that the net product values of 6 ecosystems, includingcultivated land, forest land, grassland, wetland, water area and unused land, were respectively 1481.925, 8194.806, 4176.277, 4245.760, 3177.084 and 133.762 billion CNY. Spatial heterogeneity of ecosystem net product in different provinces was distinct. Ecological well-being per capita of forest land, grassland, wetland, cultivated land and unused land in eastern and middle provinces were under the red line and less than the national average. The spatial distribution of 9 kinds of ecological well-being per capita split at Hu's line with high value in northwest and low value in southeast, and was aggravated by differences in density of population and land resources gift.

Silver Nanoclusters: From Design Principles to Practical Applications

KAUST Repository

Abdulhalim, Lina G.

2015-12-08

A strategy based on reticulating metal ions and organic ligands into atomically precise gold and silver nanoclusters (NCs) with high monodispersity has been advanced to a point that allows the design of NCs with strict stoichiometries, functionalities and valence. Of the Ag NCs discovered, Ag44 is the most studied, not only due to its high absorption that transcends the visible spectrum suitable for photovoltaics but also because of its long excited state lifetime, as revealed by nanosecond transient absorption spectroscopy. A major principle discovered in this dissertation is the ability to produce Ag44 in scalable amounts and with high stability in addition to modulation of the functional groups of the organic ligands via a fast and complete ligand exchange process. This new discovery has led to the development of synthetic designs in which new sizes were obtained by varying the reaction parameters (e.g., ligands functionality, reaction temperature and time), namely, Ag29 using dithiols and phosphines. The synthesized NCs possess tetravalent functionalities that facilitate their crystallization and characterization. Furthermore, Ag29 glows red and is therefore a possible candidate for sensing and imaging applications.

Towards a commitment-based reference ontology for services

NARCIS (Netherlands)

Nardi, Julio Cesar; de Almeida Falbo, Ricardo; Andrade Almeida, João; Guizzardi, Giancarlo; Ferreira Pires, Luis; van Sinderen, Marten J.; Guarino, Nicola; Gašević, Dragan; Hatala, Marek; Motahari Nezhad, Hamid R.; Reichert, Manfred

The concept of “service” has been characterized by different disciplines and authors from various points of view. The variety of characterizations reveals that this notion, although an intuitive one, is far from trivial. Given the importance of services in enterprise computing and Service Science in

CIO in a Service Economy

Science.gov (United States)

Sorenson, Paul G.

The role of the Chief Information Officer (CIO) has evolved considerably since its inception in the 1980s. This paper begins with a brief review of the evolution of this role and sets the stage for future change brought about by the rise of the service economy. The enterprise of the future is then characterized based on an important global study by IBM. Using this characterization, the future challenges for CIOs in areas such as strategic planning, governance and operations management of information technology services are assessed from the perspectives of the four major elements of a service system (technology, people, organization and shared information). The paper concludes with a summary of the important findings, pointing to the challenge that CIOs of the future must be the leaders in their organizations in the delivery of smarter, on-demand service systems to smarter customers.

Hydrothermal synthesis of polyethylenimine-protected high luminescent Pt-nanoclusters and their application to the detection of nitroimidazoles

International Nuclear Information System (INIS)

Xu, Na; Li, Hong-Wei; Wu, Yuqing

2017-01-01

A novel one-step hydrothermal synthesis of highly fluorescent platinum nanoclusters protected by polyethylenimine (Pt-NCs@PEI) is described. The products are characterized well by UV–vis absorption, fluorescence spectra, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) imaging. The Pt-NCs@PEI possess high quantum yield at 28%, which is the relatively high one among the reported Pt-NCs; especially, the synthesis is in one-step and the reaction time is much shorter (<1 h) than the related methods. In addition, the Pt-NCs@PEI have large Stocks-shift (∼150 nm), high tolerability to the extreme pH and high ionic strengths, and excellent photo-stability under UV–vis irradiation, lay the foundation for the practical bio-applications. Finally, the obtained Pt-NCs@PEI are used to determine trace amount of metronidazole (MTZ) in buffer solution in showing a linear response over a concentration range of 0.25–300 μM and a low detection limit of 0.1 μM. Furthermore, the related investigation on response mechanism will be helpful to design and synthesize new metal nanoclusters as fluorescent probe to detect the trace amount of harmful medicine residuum as nitroimidazoles in human body. - Highlights: • This paper provides the first hydrothermal synthesis of platinum nanoclusters. • The prepared polyethylenimine-protected platinum nanoclusters possess high quantum yield of 28%. • A new method to detect trace amount of metronidazole in urine is proposed.

Hydrothermal synthesis of polyethylenimine-protected high luminescent Pt-nanoclusters and their application to the detection of nitroimidazoles

Energy Technology Data Exchange (ETDEWEB)

Xu, Na [State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012 (China); College of Materials Science and Engineering, Jilin Institute of Chemical Technology, Jilin, 132022 (China); Li, Hong-Wei, E-mail: lihongwei@jlu.edu.cn [State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012 (China); Wu, Yuqing, E-mail: yqwu@jlu.edu.cn [State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun, 130012 (China)

2017-03-15

A novel one-step hydrothermal synthesis of highly fluorescent platinum nanoclusters protected by polyethylenimine (Pt-NCs@PEI) is described. The products are characterized well by UV–vis absorption, fluorescence spectra, X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) imaging. The Pt-NCs@PEI possess high quantum yield at 28%, which is the relatively high one among the reported Pt-NCs; especially, the synthesis is in one-step and the reaction time is much shorter (<1 h) than the related methods. In addition, the Pt-NCs@PEI have large Stocks-shift (∼150 nm), high tolerability to the extreme pH and high ionic strengths, and excellent photo-stability under UV–vis irradiation, lay the foundation for the practical bio-applications. Finally, the obtained Pt-NCs@PEI are used to determine trace amount of metronidazole (MTZ) in buffer solution in showing a linear response over a concentration range of 0.25–300 μM and a low detection limit of 0.1 μM. Furthermore, the related investigation on response mechanism will be helpful to design and synthesize new metal nanoclusters as fluorescent probe to detect the trace amount of harmful medicine residuum as nitroimidazoles in human body. - Highlights: • This paper provides the first hydrothermal synthesis of platinum nanoclusters. • The prepared polyethylenimine-protected platinum nanoclusters possess high quantum yield of 28%. • A new method to detect trace amount of metronidazole in urine is proposed.

Water concentration controlled hydrolysis and crystallization in n-octanol to TiO{sub 2} nanocrystals with size below 10 nm

Energy Technology Data Exchange (ETDEWEB)

Wang Meilan [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); He Tao, E-mail: htzy79@yahoo.com.cn [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); Pan Yanfei; Liao Weiping [School of Chemical and Biological Science and Engineering, Yantai University, Yantai 264005 (China); Zhang Shangzhou; Du Wei [School of Environment and Materials Engineering, Yantai University, Yantai 264005 (China)

2011-11-01

Highlights: {yields} Controlled hydrolysis of alkoxide was realized by adjusting water concentration. {yields} Carrying out hydrolysis under different water concentration gave hydrolyzed intermediate with different composition. {yields} A precise size control below 10 nm for anatase TiO{sub 2} nanocrystals was realized. - Abstract: Hydrolysis of tetrabutyl titanate (TBT) and crystallization from hydrolyzed intermediates were carried out in a simple ternary system including n-octanol, TBT and water. Anatase TiO{sub 2} nanocrystals (NCS) were prepared with precise size control below 10 nm. The hydrolysis rate at different water concentration (C{sub water}) was evaluated by measuring the induction time before turbidity changing of the synthetic solution. Fourier transform infrared spectrum (FT-IR) and thermogravimetric/differential thermal analysis (TG/DTA) techniques were applied to make clear the composition of hydrolyzed intermediates obtained at different C{sub water}. Powder X-ray diffraction (XRD) technique was used to track the crystallization process of TiO{sub 2} NCS. Transmission electron microscopy (TEM), XRD, FT-IR and TG/DTA techniques were used to characterize the particular properties of NCS. The C{sub water} controlled mechanism responsible for the slow hydrolysis and crystallization were discussed. Since no other organic capping ligands or rapid injecting techniques were used to limit NCS' growth and the solvent n-octanol can be easily separated and reused, this simple synthetic process is of green chemistry and has application potential in large-scale preparation of inorganic NCS.

White light generation tuned by dual hybridization of nanocrystals and conjugated polymers

International Nuclear Information System (INIS)

Demir, Hilmi Volkan; Nizamoglu, Sedat; Ozel, Tuncay; Mutlugun, Evren; Huyal, Ilkem Ozge; Sari, Emre; Holder, Elisabeth; Tian Nan

2007-01-01

Dual hybridization of highly fluorescent conjugated polymers and highly luminescent nanocrystals (NCs) is developed and demonstrated in multiple combinations for controlled white light generation with high color rendering index (CRI) (> 80) for the first time. The generated white light is tuned using layer-by-layer assembly of CdSe/ZnS core-shell NCs closely packed on polyfluorene, hybridized on near-UV emitting nitride-based light emitting diodes (LEDs). The design, synthesis, growth, fabrication and characterization of these hybrid inorganic-organic white LEDs are presented. The following experimental realizations are reported: (i) layer-by-layer hybridization of yellow NCs (λ PL =580 nm) and blue polyfluorene (λ PL =439 nm) with tristimulus coordinates of (x, y)=(0.31, 0.27), correlated color temperature of T c =6962 K and CRI of R a =53.4; (ii) layer-by-layer assembly of yellow and green NCs (λ PL =580 and 540 nm) and blue polyfluorene (λ PL =439 nm) with (x, y)=(0.23, 0.30), T c =14395 K and R a =65.7; and (iii) layer-by-layer deposition of yellow, green and red NCs (λ PL =580, 540 and 620 nm) and blue polyfluorene (λ PL =439 nm) with (x, y)=(0.38, 0.39), T c =4052 K and R a = 83.0. The CRI is demonstrated to be well controlled and significantly improved by increasing multi-chromaticity of the NC and polymer emitters

Dual functional rhodium oxide nanocorals enabled sensor for both non-enzymatic glucose and solid-state pH sensing.

Science.gov (United States)

Dong, Qiuchen; Huang, Yikun; Song, Donghui; Wu, Huixiang; Cao, Fei; Lei, Yu

2018-07-30

Both pH-sensitive and glucose-responsive rhodium oxide nanocorals (Rh 2 O 3 NCs) were synthesized through electrospinning followed by high-temperature calcination. The as-prepared Rh 2 O 3 NCs were systematically characterized using various advanced techniques including scanning electron microscopy, X-ray powder diffraction and Raman spectroscopy, and then employed as a dual functional nanomaterial to fabricate a dual sensor for both non-enzymatic glucose sensing and solid-state pH monitoring. The sensing performance of the Rh 2 O 3 NCs based dual sensor toward pH and glucose was evaluated using open circuit potential, cyclic voltammetry and amperometric techniques, respectively. The results show that the as-prepared Rh 2 O 3 NCs not only maintain accurate and reversible pH sensitivity of Rh 2 O 3 , but also demonstrate a good electrocatalytic activity toward glucose oxidation in alkaline medium with a sensitivity of 11.46 μA mM -1 cm -2 , a limit of detection of 3.1 μM (S/N = 3), and a reasonable selectivity against various interferents in non-enzymatic glucose detection. Its accuracy in determining glucose in human serum samples was further demonstrated. These features indicate that the as-prepared Rh 2 O 3 NCs hold great promise as a dual-functional sensing material in the development of a high-performance sensor forManjakkal both solid-state pH and non-enzymatic glucose sensing. Copyright © 2018 Elsevier B.V. All rights reserved.

Fabrication of 3-methoxyphenol sensor based on Fe3O4 decorated carbon nanotube nanocomposites for environmental safety: Real sample analyses.

Directory of Open Access Journals (Sweden)

Mohammed M Rahman

Full Text Available Iron oxide ornamented carbon nanotube nanocomposites (Fe3O4.CNT NCs were prepared by a wet-chemical process in basic means. The optical, morphological, and structural characterizations of Fe3O4.CNT NCs were performed using FTIR, UV/Vis., FESEM, TEM; XEDS, XPS, and XRD respectively. Flat GCE had been fabricated with a thin-layer of NCs using a coating binding agent. It was performed for the chemical sensor development by a dependable I-V technique. Among all interfering analytes, 3-methoxyphenol (3-MP was selective towards the fabricated sensor. Increased electrochemical performances for example elevated sensitivity, linear dynamic range (LDR and continuing steadiness towards selective 3-MP had been observed with chemical sensor. The calibration graph found linear (R2 = 0.9340 in a wide range of 3-MP concentration (90.0 pM ~ 90.0 mM. The limit of detection and sensitivity were considered as 1.0 pM and 9×10-4 μAμM-1cm-2 respectively. The prepared of Fe3O4.CNT NCs by a wet-chemical progression is an interesting route for the development of hazardous phenolic sensor based on nanocomposite materials. It is also recommended that 3-MP sensor is exhibited a promising performances based on Fe3O4.CNT NCs by a facile I-V method for the significant applications of toxic chemicals for the safety of environmental and health-care fields.

Biomimetic Mineralization of Gold Nanoclusters as Multifunctional Thin Films for Glass Nanopore Modification, Characterization, and Sensing.

Science.gov (United States)

Cao, Sumei; Ding, Shushu; Liu, Yingzi; Zhu, Anwei; Shi, Guoyue

2017-08-01

Hurdles of nanopore modification and characterization restrain the development of glass capillary-based nanopore sensing platforms. In this article, a simple but effective biomimetic mineralization method was developed to decorate glass nanopore with a thin film of bovine serum albumin-protected Au nanocluster (BSA-Au NC). The BSA-Au NC film emitted a strong red fluorescence whereby nondestructive characterization of Au film decorated at the inner surface of glass nanopore can be facilely achieved by a fluorescence microscopy. Besides, the BSA molecules played dual roles in the fabrication of functionalized Au thin film in glass nanopore: they not only directed the synthesis of fluorescent Au thin film but also provided binding sites for recognition, thus achieving synthesis-modification integration. This occurred due to the ionized carboxyl groups (-COO - ) of a BSA coating layer on Au NCs which can interacted with arginine (Arg) via guanidinium groups. The added Arg selectively led to the change in the charge and ionic current of BSA-Au NC film-decorated glass nanopore. Such ionic current responses can be used for quantifying Arg with a detection limit down to 1 fM, which was more sensitive than that of previous sensing systems. Together, the designed method exhibited great promise in providing a facile and controllable solution for glass nanopore modification, characterization, and sensing.

Humoral activity of cord blood-derived stem/progenitor cells: implications for stem cell-based adjuvant therapy of neurodegenerative disorders.

Directory of Open Access Journals (Sweden)

Edyta Paczkowska

Full Text Available BACKGROUND: Stem/progenitor cells (SPCs demonstrate neuro-regenerative potential that is dependent upon their humoral activity by producing various trophic factors regulating cell migration, growth, and differentiation. Herein, we compared the expression of neurotrophins (NTs and their receptors in specific umbilical cord blood (UCB SPC populations, including lineage-negative, CD34(+, and CD133(+ cells, with that in unsorted, nucleated cells (NCs. METHODS AND RESULTS: The expression of NTs and their receptors was detected by QRT-PCR, western blotting, and immunofluorescent staining in UCB-derived SPC populations (i.e., NCs vs. lineage-negative, CD34(+, and CD133(+ cells. To better characterize, global gene expression profiles of SPCs were determined using genome-wide RNA microarray technology. Furthermore, the intracellular production of crucial neuro-regenerative NTs (i.e., BDNF and NT-3 was assessed in NCs and lineage-negative cells after incubation for 24, 48, and 72 h in both serum and serum-free conditions. We discovered significantly higher expression of NTs and NT receptors at both the mRNA and protein level in lineage-negative, CD34(+, and CD133(+ cells than in NCs. Global gene expression analysis revealed considerably higher expression of genes associated with the production and secretion of proteins, migration, proliferation, and differentiation in lineage-negative cells than in CD34(+ or CD133(+ cell populations. Notably, after short-term incubation under serum-free conditions, lineage-negative cells and NCs produced significantly higher amounts of BDNF and NT-3 than under steady-state conditions. Finally, conditioned medium (CM from lineage-negative SPCs exerted a beneficial impact on neural cell survival and proliferation. CONCLUSIONS: Collectively, our findings demonstrate that UCB-derived SPCs highly express NTs and their relevant receptors under steady-state conditions, NT expression is greater under stress-related conditions and

Characterization and Application of DNA-templated Silver Nanoclusters and Polarized Spectroscopy of Self-Assembled Nanostructures

DEFF Research Database (Denmark)

Carro-Temboury, Miguel R.

In this thesis two different systems are investigated envisioning their potential applications: DNA-templated silver nanoclusters (DNA-AgNCs) and ionic self-assembled (ISA) nanostructures based on azo-dyes. Mainly Visible-NIR spectroscopy was used to probe electronic transitions with absorbance a...

Service orientation of the restaurant employees

OpenAIRE

Gagić, Snježana; Vuković-Jovičić, Ana; Petrović, Marko D.

2017-01-01

The service orientation program developed for restaurant employees can be a competitive advantage for a restaurant operation. Service orientation has been characterized as the disposition of employees to be helpful, thoughtful, considerate, and co-operative towards customers. Customer-oriented behaviors include: helping customers; helping customers to assess their needs; offering service that will satisfy those needs; describing services accurately; avoiding deceptive manipulations; and avoid...

The effect of defective DNA double-strand break repair on mutations and chromosome aberrations in the Chinese hamster cell mutant XR-V15B

International Nuclear Information System (INIS)

Helbig, R.; Speit, G.; Zdzienicka, M.Z.

1995-01-01

The radiosensitive Chinese hamster cell line XR-V15B was used to study the effect of decreased rejoining of DNA double-strand breaks (DSBs) on gene mutations and chromosome aberrations. XR-V15B cells are hypersensitive to the cytotoxic effects of neocarzinostatin (NCS) and methyl methanesulfonate (MMS). Both mutagens induced more chromosome aberrations in XR-V15B cells than in the parental cell strain. The clastogenic action of NCS was characterized by the induction of predominantly chromosome-type aberrations in cells of both strains, whereas MMS induced mainly chromatid aberrations. The frequency of induced gene mutations at the hprt locus was not increased compared to the parental V79 cells when considering the same survival level. Molecular analysis by multiplex polymerase chain reaction (PCR) of mutants induced by NCS revealed a high frequency of deletions in cells of both cell lines. Methyl methane-sulfonate induced mainly mutations without visible change in the PCR pattern, which probably represent point mutations. Our findings suggest a link between a defect in DNA DSB repair and increased cytotoxic and clastogenic effects. However, a decreased ability to rejoin DNA DSBs does not seem to influence the incidence and types of gene mutations at the hprt locus induced by NCS and MMS. 28 refs., 4 figs., 3 tabs

AVTA Federal Fleet PEV Readiness Data Logging and Characterization Study for the United States Forest Service: Caribou-Targhee National Forest

Energy Technology Data Exchange (ETDEWEB)

Stephen Schey; Jim Francfort; Ian Nienhueser

2014-06-01

Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for U.S. Department of Energy Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (ITSNA) to collect and evaluate data on federal fleet operations as part of the Advanced Vehicle Testing Activity’s Federal Fleet Vehicle Data Logging and Characterization study. The Advanced Vehicle Testing Activity study seeks to collect and evaluate data to validate the utilization of advanced electric drive vehicle transportation. This report focuses on the Caribou-Targhee National Forest (CTNF) fleet to identify daily operational characteristics of select vehicles and report findings on vehicle and mission characterizations to support the successful introduction of plug-in electric vehicles (PEVs) into the agencies’ fleets. Individual observations of these selected vehicles provide the basis for recommendations related to electric vehicle adoption and whether a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV) (collectively plug-in electric vehicles, or PEVs) can fulfill the mission requirements. ITSNA acknowledges the support of Idaho National Laboratory and CTNF for participation in the study. ITSNA is pleased to provide this report and is encouraged by enthusiasm and support from the Forest Service and CTNF personnel.

Influence of spray drying and dispersing agent on surface and dissolution properties of griseofulvin micro and nanocrystals.

Science.gov (United States)

Shah, Dhaval A; Patel, Manan; Murdande, Sharad B; Dave, Rutesh H

2016-11-01

The purpose for the current research is to compare and evaluate physiochemical properties of spray-dried (SD) microcrystals (MCs), nanocrystals (NCs), and nanocrystals with a dispersion agent (NCm) from a poorly soluble compound. The characterization was carried out by performing size and surface analysis, interfacial tension (at particle moisture interface), and in-vitro drug dissolution rate experiments. Nanosuspensions were prepared by media milling and were spray-dried. The SD powders that were obtained were characterized morphologically using scanning electron microscopy (SEM), polarized light microscopy (PLM), and Flowchem. Solid-state characterization was performed using X-ray powder diffraction (XRPD), Fourier transfer infrared spectroscopy (FT-IR), and differential scanning calorimetry (DSC) for the identification of the crystalline nature of all the SD powders. The powders were characterized for their redispersion tendency in the water and in pH 1.2. Significant differences in redispersion were noted for both the NCs in both dissolution media. The interfacial tension for particle moisture interface was determined by applying the BET (Braunauer-Emmett-Teller) equation to the vapor sorption data. No significant reduction in the interfacial tension was observed between MCs and NCs; however, a significant reduction in the interfacial tension was observed for NCm at both 25 °C and 35 °C temperatures. The difference in interfacial tension and redispersion behavior can be attributed to a difference in the wetting tendency for all the SD powders. The dissolution studies were carried out under sink and under non-sink conditions. The non-sink dissolution approach was found suitable for quantification of the dissolution rate enhancement, and also for providing the rank order to the SD formulations.

The Evolution and Challenges of the Danish Civil Service System

DEFF Research Database (Denmark)

Hansen, Morten Balle

2013-01-01

service is examined. The Danish civil service system has been characterized by long-term gradual evolution and adoption of many of the prevailing institutions in medieval and modern European state administration. This adaptation to prevailing trends has been predominantly characterized by integration...

Tradeoffs between quality-of-control and quality-of-service in large-scale nonlinear networked control systems

NARCIS (Netherlands)

Borgers, D. P.; Geiselhart, R.; Heemels, W. P. M. H.

2017-01-01

In this paper we study input-to-state stability (ISS) of large-scale networked control systems (NCSs) in which sensors, controllers and actuators are connected via multiple (local) communication networks which operate asynchronously and independently of each other. We model the large-scale NCS as an

Performance Trade-offs in Client-Side Service Delegation

NARCIS (Netherlands)

Nasr, K.A.; Gross, H.G.; Van Deursen, A.

2011-01-01

Service Oriented Architecture, which builds on distributed computing platforms, is increasingly being adopted by organizations in both public and private sectors. Migration from traditional monolithic systems to services, in particular web services, characterizes much of systems evolution today.

Thiocyanato species of uranium(IV)

International Nuclear Information System (INIS)

Loyson, P.L.R.

1974-12-01

The aim of this thesis was to study the system U +4 /ClO 4 - /NCS - /HMPA/ - Solvent. This was done by means of various physical chemical methods. Spectrophotometric and conductometric evidence indicated that the following are the important species, which exist in acetone solution: (U(ClO 4 ) 3 .3acetone) + , (U(NCS) 3 .5acetone) + , (U 2 (NCS) 9 .6acetone) - , (U(NCS) 3 .2HMPA.3acetone) + , (U(NCS) 5 .2HMPA) - , (U(ClO 4 ) 3 .3HMPA) + , (U(NCS).5HMPA) +3 , (U(NCS) 2 .4HMPA) +2 and (U(NCS) 3 .3HMPA) + . The replacement of the large ClO 4 - ion by the much smaller NCS - anion results in a change in coordination of the U +4 , from six to eight. The formation of the species (U(NCS) 5 .2HMPA) - wasalso suggested by infrared studies and solubility determinations. The effect of a polar solvent on U(NCS) 4 .4HMPA was also studied, which indicated that, on solvation in methyl cyanide, U(NCS) 4 .4HMPA loses bound HMPA molecules. The ultimate goal of this project, i.e. the determination of the successive stability constants of the uranium(IV)thiocyanato complexes in acetone, was not reached, however, due to limitations of the computer program used. A qualitative treatment revealed that the stability of (U(NCS) 3 .5acetone) + , in acetone, is of the same order of magnitude as that of Co(NCS) 3 - ; similarly the species (U 2 (NCS) 9 .6acetone) - seems to be as stable as C0(NCS) 4 =. It was also indicated that excess U +4 cannot remove all bound NCS - from Co +2 . Finally the thiocyanato complexes of U +4 , relative to those of CO +2 , seem to be more stable in methyl cyanide, a N-donor solvent, than in acetone, an O-donor solvent

Dynamic and structural study of neocarzinostatin native and denatured states, by differential microcalorimetry, optical spectroscopies and X-ray and neutron scattering

International Nuclear Information System (INIS)

Russo, Daniela

2000-01-01

A structural and dynamic characterization of proteins denatured states is essential to the understanding of mechanisms which control proteins folding. It is in this framework that this study has been undertaken in taking as model the neocarzinostatin globular protein. It is formed with seven cell-layers which form a barrel pattern maintained by two bi-sulfur bonds. A full characterization of native and denatured states, both from structural and dynamic point of view, has been implemented with several techniques able to bring data at different levels. During the experiments, ncs has been stabilized by temperature and by the use of a chaotropic agent: the guanidinium chloride (gdmcl). Small angle x-ray and neutron scattering have allowed us to obtain data on the variation of the protein compactness in terms of gdmcl temperature and concentration. The diffusion spectra show that ncs loses completely its globular structure above 80 C or in presence of about 5 m of gdmcl. Temperature and concentration of half denaturation are tm= 70 C and cm=3.5 m (in heavy water), respectively. Spectra analysis of strongly denatured protein has allowed us to obtain values of its chain length and of its persistence length which are in agreement with those theoretically estimated. Experiments have been carried out too to measure the radius of gyration to zero concentration and the second virial coefficient of the solution in order to estimate the interactions between the molecules. A full characterization has been performed in terms of gdmcl temperature and concentration by fluorescence and circular dichroism. These two techniques reveal the variations of the local three-dimensional structure and secondary structure of the protein respectively. Microcalorimetry measurements have shown that thermal denaturation of ncs is completely reversible and has been used to measure the enthalpy variation during the transition. At last, it has been possible to study ncs intramolecular dynamics in

White light generation tuned by dual hybridization of nanocrystals and conjugated polymers

Energy Technology Data Exchange (ETDEWEB)

Demir, Hilmi Volkan [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Nizamoglu, Sedat [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Ozel, Tuncay [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Mutlugun, Evren [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Huyal, Ilkem Ozge [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Sari, Emre [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Holder, Elisabeth [Functional Polymers Group and Institute of Polymer Technology, University of Wuppertal, Gaussstrasse 20, D-42097 Wuppertal (Germany); Tian Nan [Functional Polymers Group and Institute of Polymer Technology, University of Wuppertal, Gaussstrasse 20, D-42097 Wuppertal (Germany)

2007-10-15

Dual hybridization of highly fluorescent conjugated polymers and highly luminescent nanocrystals (NCs) is developed and demonstrated in multiple combinations for controlled white light generation with high color rendering index (CRI) (> 80) for the first time. The generated white light is tuned using layer-by-layer assembly of CdSe/ZnS core-shell NCs closely packed on polyfluorene, hybridized on near-UV emitting nitride-based light emitting diodes (LEDs). The design, synthesis, growth, fabrication and characterization of these hybrid inorganic-organic white LEDs are presented. The following experimental realizations are reported: (i) layer-by-layer hybridization of yellow NCs ({lambda}{sub PL}=580 nm) and blue polyfluorene ({lambda}{sub PL}=439 nm) with tristimulus coordinates of (x, y)=(0.31, 0.27), correlated color temperature of T{sub c}=6962 K and CRI of R{sub a}=53.4; (ii) layer-by-layer assembly of yellow and green NCs ({lambda}{sub PL}=580 and 540 nm) and blue polyfluorene ({lambda}{sub PL}=439 nm) with (x, y)=(0.23, 0.30), T{sub c}=14395 K and R{sub a}=65.7; and (iii) layer-by-layer deposition of yellow, green and red NCs ({lambda}{sub PL}=580, 540 and 620 nm) and blue polyfluorene ({lambda}{sub PL}=439 nm) with (x, y)=(0.38, 0.39), T{sub c}=4052 K and R{sub a}= 83.0. The CRI is demonstrated to be well controlled and significantly improved by increasing multi-chromaticity of the NC and polymer emitters.

AVTA Federal Fleet PEV Readiness Data Logging and Characterization Study for Department of Health and Human Services – ASPR

Energy Technology Data Exchange (ETDEWEB)

Schey, Steve [Idaho National Lab. (INL), Idaho Falls, ID (United States); Francfort, Jim [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-06-01

This report focuses on the Department of Health and Human Services, Assistant Secretary for Preparedness and Response fleet to identify daily operational characteristics of select vehicles and report findings on vehicle and mission characterizations to support the successful introduction of PEVs into the agency’s fleet. Individual observations of these selected vehicles provide the basis for recommendations related to electric vehicle adoption and whether a battery electric vehicle or plug-in hybrid electric vehicle (collectively referred to as PEVs) can fulfill the mission requirements.

Synthesis and characterization of complexes of early actinides with tridentate Schiff base ligands

International Nuclear Information System (INIS)

Mansingh, P.S.; Dash, K.C.

1995-01-01

A series of thorium(IV) and dioxouranium(VI) complexes have been synthesised with tridentate Schiff base ligands (N 2 O donor set) obtained by in-situ condensation of N, N-dimethylethylenediamine with o-hydroxy aromatic aldehydes such as salicylaldehyde (HL) or o-hydroxy naphthaldehyde (HL'). While with dioxouranium(VI), the ligands are coordinated in a neutral manner and act as tridentate donors forming complexes of the type UO 2 (HL)X 2 or UO 2 (HL')X 2 (X=Cl,I,NCS,NO 3 ,CH 3 COO) with thorium(IV) they are coordinated as deprotonated tridentate ligands yielding complexes of the type Th(L') 2 X 2 (X=I,NCS,NO 3 ). The IR spectra show that the thiocyanate group is actually N-bonded unidentate isothiocyanate and both the nitrate and the acetate groups are bonded in bidentate manner while the ligands are bonded in tridentate manner in these complexes. The PMR spectra confirm the mode of bonding of the ligands either as neutral or as deprotonated species. The thermogravimetric analyses indicate the stability of the complexes. (author). 22 refs., 1 tab

New applications of orientation imaging microscopy (OIM) for characterizing nuclear component failure modes, reliability assessment, and fitness-for-service

International Nuclear Information System (INIS)

Lehockey, E.M.; Brennenstuhl, A.M.; Pagan, S.; Clark, M.A.; Perovic, V.

2007-01-01

Orientation Imaging Microscopy (OIM) has proved a valuable asset for evaluating material performance as far as establishing the root cause and mechanism(s) of in-service degradation, and the likelihood of the onset of future degradation. Strains from deformation/cold work are imaged based on the spatial density of sub-structure distributed globally or surrounding defects/irregularities, which concentrate stresses responsible for driving degradation. This is complimented with measurements of material properties including texture, Taylor Factor, grain boundary structure, and grain size that contribute to resisting propagation of pre-existing defects and/or nucleating future attack. From evaluating the factors driving degradation within the context of microstructure properties that govern material susceptibility come estimates for the likelihood of attack as a necessary element of establishing fitness for service. By way of numerous examples the merits and limitations of OIM are summarized and compared with other characterization techniques. (author)

Fatigue characterization of mechanical components in service

Directory of Open Access Journals (Sweden)

G. Fargione

2013-10-01

Full Text Available The quickly identify of fatigue limit of a mechanical component with good approximation is currently a significant practical problem not yet resolved in a satisfactory way. Generally, for a mechanical component, the fatigue strength reduction factor (i is difficult to evaluate especially when it is in service.In this paper, the procedures for crack paths individuation and consequently damage evaluation (adopted in laboratory for stressed specimens with planned load histories are applied to mechanical components, already failed during service. The energy parameters, proposed by the authors for the evaluation of the fatigue behavior of the materials [1-5], are defined on specimens derived from a flange bolts. The flange connecting pipes at high temperature and pressure. Due to the loss of the seal, the bolts have been subjected to a hot flow steam addition to the normal stress.The numerical analysis coupled experimental analysis (measurement of surface temperature during static and dynamic tests of specimens taken from damaged tie rods, has helped to determine the causes of failure of the tie rods.The determination of an energy parameter for the evaluation of the damage showed that factors related to the heat release of the material (loaded may also help to understand the causes of failure of mechanical components.

Characterizing governance and benefits of payments for watershed services in Europe

OpenAIRE

Leonardi, Alessandro

2015-01-01

Globally, Payments for Watershed Services (PWS) make-up the largest ecosystem service market (Bennett et al., 2014b). Driven by the negative impacts of climate change and economic development for water quantity and quality provision, hydrological services are assuming a leading priority among forest and agriculture-based ecosystems. Indeed, afforestation and sustainable agriculture tend to be among the most rewarded management practices under contracts aiming to achieve additionality in upstr...

Preschool Children (Ages 2 to 4 Years) - NCS Dietary Assessment Literature Review

Science.gov (United States)

The preschool years are characterized as a time of increasing autonomy, expanding language skills, increasing ability to control behavior, and broadening social circumstances, such as attending preschool or staying with friends or relatives.

Organo-Functionalization of Silicon Nanocrystals Synthesized by Inductively Coupled Plasma Chemical Vapor Deposition

Energy Technology Data Exchange (ETDEWEB)

Lee, Don-Sung; Choe, Dong-Hoe; Jeong, Hyun-Dam [Chonnam National University, Gwangju (Korea, Republic of); Yoo, Seung-Wan; Kim, Jung-Hyung [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

2016-05-15

Octadecyl-terminated silicon nanocrystals (ODE-Si NCs) are obtained via a surface-initiated thermal hydrosilylation reaction on hydride-terminated Si NCs (H-Si NCs). Pristine Si NCs were synthesized at the gram scale by using inductively coupled plasma chemical vapor deposition (ICP-CVD) . The H-Si NCs were produced through a chemical etching process with hydrofluoric acid (HF), ethanol (EtOH), and distilled water (d-H{sub 2}O). The results obtained from X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM) indicate that the synthesized Si NCs obtained via ICP-CVD have diamond cubic-structured silicon with a grain size of 10 nm and a densely packed Si NC array consisting of individual NCs. Organo-functionalized Si NCs, i.e., ODE-Si NCs, are well soluble in organic solvent whereas pristine Si NCs synthesized through ICP-CVD are not. The surface chemistry of the ODE-Si NCs was confirmed via Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy ({sup 1}H-NMR), and field emission transmission electron microscopy (FE-TEM). Thereby, these newly synthesized and scalable organo-functionalized Si NCs are applicable as raw materials for practical use in devices by tuning the surface chemistry with various capping molecules.

Electronic states and phonon properties of Ge{sub x}Si{sub 1−x} nanostructures

Energy Technology Data Exchange (ETDEWEB)

Zhao, P.Q. [Department of Applied Physics, Nanjing Tech University, Nanjing 211816 (China); National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Liu, L.Z. [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Yang, Y.M. [Department of Physics, Southern University, Nanjing 210096 (China); Wu, X.L., E-mail: hkxlwu@nju.edu.cn [National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093 (China); Department of Physics, NingBo University, NingBo 3153001 (China)

2015-07-15

Ge{sub x}Si{sub 1−x} nanostructures that can be manipulated through size reduction, geometry variation, and alloying, are considered as one of the key developments for next generation technologies, due to their easy processing, unique properties, and compatibility with the existent silicon-based microelectronic industry. In this review, we have thoroughly discussed the major advances in electronic structures and phonon properties of Ge{sub x}Si{sub 1−x} nanocrystals (NCs). Experimental and theoretical characterization related to several main factors, for example, size, composition, strain, temperature, and interface and surface were presented with special emphasis in low-frequency Raman scattering. Current difficulties in explaining the Raman spectra are the assignment of the low-frequency modes because of the complexity of the environment around the NCs, thus different theoretical models are introduced in detail to deal with different properties of Ge{sub x}Si{sub 1−x} alloy NCs including Lamb’s theory, complex-frequency (CF) model, core–shell matrix (CMS) model and spatial coherence effect model. - Highlights: • Major advances in electronic structures and phonon properties of Ge{sub x}Si{sub 1−x} nanocrystals are discussed thoroughly. • Experimental and theoretical characterization related to size, composition, strain, temperature, and interface/surface are elucidated. • Low-frequency Raman spectra are specially described based on spatial coherence effect model.

Performance Trade-offs in Client-Side Service Delegation

OpenAIRE

Nasr, K.A.; Gross, H.G.; Van Deursen, A.

2011-01-01

Service Oriented Architecture, which builds on distributed computing platforms, is increasingly being adopted by organizations in both public and private sectors. Migration from traditional monolithic systems to services, in particular web services, characterizes much of systems evolution today. This paper analyzes some of the performance and modularization problems involved in current service-oriented computing. It investigates under which circumstances the communication between service prov...

Synthesis and Characterization of a Ru(II Complex with Functionalized Phenanthroline Ligands Having Single-Double Linked Anthracenyl and 1-Methoxy-1-buten-3-yne Moieties

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2010-10-01

Full Text Available Two series of bidentate polypyridine ligands, made of phenanthroline chelating subunits having substituted mono-and di-anthracenyl groups, and 1-methoxy-1-buten-3-yne at the 4 and 7-positions with the corresponding heteroleptic Ru(II complex have been synthesized and characterized. The complex is formulated as [(Ru(L1(L2(NCS2], (where L1 = 4-(9-dianthracenyl-10-(2,3-dimethylacrylic acid-7-(9-anthracenyl-10-(2,3-dimethylacrylic acid-1,10-phenanthroline and L2 = 4,7-bis(1-methoxy-1-buten-3-yne-1,10-phenanthroline. The Ru(II complex shows characteristic broad and intense metal-to-ligand charge transfer (MLCT bands absorption and appreciable photoluminescence spanning the visible region. The ligands and complex were characterized by FT-IR, 1H, 13C NMR spectroscopy, UV-Vis, photoluminescence and elemental analysis (see in supplementary materials. The anchoring groups in both ligands have allowed an extended delocalization of acceptor orbital of the metal-to-ligand charge-transfer (MLCT excited state.

Long-term effects of mental disorders on educational attainment in the National Comorbidity Survey ten-year follow-up.

Science.gov (United States)

Mojtabai, Ramin; Stuart, Elizabeth A; Hwang, Irving; Eaton, William W; Sampson, Nancy; Kessler, Ronald C

2015-10-01

The study sought to examine the association of mental disorders with educational attainment in a community sample. Data were from 5001 respondents aged 15-54 in the 1990-1992 National Comorbidity Survey (NCS), re-interviewed in the 2001-2003 NCS follow-up (NCS-2). Discrete-time survival analysis was used to examine the association of disorders present at baseline (NCS) or having first onset after the baseline (assessed in NCS-2) with educational outcomes among 3954 eligible respondents. Mental disorders were categorized into internalizing fear disorders (simple phobia, social phobia, panic disorder with/without agoraphobia and agoraphobia without panic disorder), internalizing anxiety-misery disorders (major depressive disorder, generalized anxiety disorder and post-traumatic stress disorder), externalizing disorders (alcohol and drug use disorders, conduct disorder) and bipolar disorder. Analyses were conducted separately in students and non-students at baseline. Among students, baseline bipolar and externalizing disorders, as well as fear, anxiety-misery and externalizing disorders with onset after baseline were associated with lower odds of high school graduation; baseline anxiety-misery disorders with lower odds of going to college; and baseline externalizing disorders and bipolar disorder with onset after baseline with lower odds of college graduation. Among non-students, baseline fear disorders were associated with lower odds of high school graduation and bipolar disorder with lower odds of going to college. Assuming that the regression coefficients represent causal effects, mental disorders accounted for 5.8-11.0% of high school and 3.2-11.4% of college non-completion. Expanding access to mental health services for youth might have a net positive societal value by helping to prevent some of these adverse educational outcomes.

Preparation and Characterization of Chitosan/Soy Protein Isolate Nanocomposite Film Reinforced by Cu Nanoclusters

Directory of Open Access Journals (Sweden)

Kuang Li

2017-06-01

Full Text Available Soy protein isolate (SPI based films have received considerable attention for use in packaging materials. However, SPI-based films exhibit relatively poor mechanical properties and water resistance ability. To tackle these challenges, chitosan (CS and endogenous Cu nanoclusters (NCs capped with protein were proposed and designed to modify SPI-based films. Attenuated total reflectance-Fourier transform infrared spectroscopy and X-ray diffraction patterns of composite films demonstrated that interactions, such as hydrogen bonds in the film forming process, promoted the cross-linking of composite films. The surface microstructure of CS/SPI films modified with Cu NCs was more uniform and transmission electron microscopy (TEM showed that uniform and discrete clusters were formed. Compared with untreated SPI films, the tensile strength and elongation at break of composite films were simultaneously improved by 118.78% and 74.93%, respectively. Moreover, these composite films also exhibited higher water contact angle and degradation temperature than that of pure SPI film. The water vapor permeation of the modified film also decreased. These improved properties of functional bio-polymers show great potential as food packaging materials.

Characterizing Coastal Ecosystem Service Trade-offs with Future Urban Development in a Tropical City.

Science.gov (United States)

Richards, Daniel R; Friess, Daniel A

2017-11-01

With rapid urbanization in the coastal zone and increasing habitat losses, it is imperative to understand how urban development affects coastal biodiversity and ecosystem service provision. Furthermore, it is important to understand how habitat fragments can best be incorporated into broader land use planning and coastal management, in order to maximize the environmental benefits they provide. In this study, we characterized the trade-offs between (a) urban development and individual mangrove environmental indicators (habitat quality and ecosystem services), and (b) between different environmental indicators in the tropical nation of Singapore. A range of biological, biophysical, and cultural indicators, including carbon, charcoal production, support for offshore fisheries, recreation, and habitat quality for a threatened species were quantified using field-based, remote sensing, and expert survey methods. The shape of the trade-off Pareto frontiers was analyzed to assess the sensitivity of environmental indicators for development. When traded off individually with urban development, four out of five environmental indicators were insensitive to development, meaning that relatively minor degradation of the indicator occurred while development was below a certain threshold, although indicator loss accelerated once this threshold was reached. Most of the pairwise relationships between the five environmental indicators were synergistic; only carbon storage and charcoal production, and charcoal production and recreational accessibility showed trade-offs. Trade-off analysis and land use optimization using Pareto frontiers could be a useful decision-support tool for understanding how changes in land use and coastal management will impact the ability of ecosystems to provide environmental benefits.

Characterizing Coastal Ecosystem Service Trade-offs with Future Urban Development in a Tropical City

Science.gov (United States)

Richards, Daniel R.; Friess, Daniel A.

2017-11-01

With rapid urbanization in the coastal zone and increasing habitat losses, it is imperative to understand how urban development affects coastal biodiversity and ecosystem service provision. Furthermore, it is important to understand how habitat fragments can best be incorporated into broader land use planning and coastal management, in order to maximize the environmental benefits they provide. In this study, we characterized the trade-offs between (a) urban development and individual mangrove environmental indicators (habitat quality and ecosystem services), and (b) between different environmental indicators in the tropical nation of Singapore. A range of biological, biophysical, and cultural indicators, including carbon, charcoal production, support for offshore fisheries, recreation, and habitat quality for a threatened species were quantified using field-based, remote sensing, and expert survey methods. The shape of the trade-off Pareto frontiers was analyzed to assess the sensitivity of environmental indicators for development. When traded off individually with urban development, four out of five environmental indicators were insensitive to development, meaning that relatively minor degradation of the indicator occurred while development was below a certain threshold, although indicator loss accelerated once this threshold was reached. Most of the pairwise relationships between the five environmental indicators were synergistic; only carbon storage and charcoal production, and charcoal production and recreational accessibility showed trade-offs. Trade-off analysis and land use optimization using Pareto frontiers could be a useful decision-support tool for understanding how changes in land use and coastal management will impact the ability of ecosystems to provide environmental benefits.

Heat-up synthesis of Ag–In–S and Ag–In–S/ZnS nanocrystals: Effect of indium precursors on their optical properties

International Nuclear Information System (INIS)

Chen, Siqi; Ahmadiantehrani, Mojtaba; Zhao, Jialong; Zhu, Shaihong; Mamalis, Athanasios G.; Zhu, Xiaoshan

2016-01-01

Cadmium-free I–III–VI nanocrystals (NCs) have recently attracted much research interests due to their excellent optical properties and low toxicity. In this work, with a simple heat-up synthetic system to prepare high quality Ag–In–S (AIS) NCs and their core/shell structures (AIS/ZnS NCs), we investigated the effect of different indium precursors (indium acetate and indium chloride) on NC optical properties. The measurements on photoluminescence spectra of AIS NCs show that the photoluminescence peak-wavelength of AIS NCs using indium acetate is in the range from 596 to 604 nm, and that of AIS NCs using indium chloride is from 641 to 660 nm. AIS and AIS/ZnS NCs using indium acetate present around 15% and 40% QYs, and both AIS and AIS/ZnS NCs using indium chloride present around 31% QYs. The photoluminescence decay study indicates that the lifetime parameters of AIS and AIS/ZnS using indium chloride are 2–4 times larger than those of AIS and AIS/ZnS NCs using indium acetate. Moreover, AIS NCs using indium chloride have a slower photobleaching dynamics than AIS NCs using indium acetate, and ZnS shell coating on both types of AIS NCs significantly enhances their photostability against UV exposure. We believe that the unique optical properties of AIS and AIS/ZnS NCs will open an avenue for these materials to be employed in broad electronic or biomedical applications. - Highlights: • High quality of AIS and AIS/ZnS NCs were prepared by heat-up. • Different indium precursors in AIS synthesis can impact AIS optical properties. • The impacted optical properties include emission colors, brightness and life time. • The reason why different indium precursors impact optical properties was explored. • The prepared NCs may have broad electronic and biomedical applications.

NDE of Possible Service-Induced PWSCC in Control Rod Drive Mechanism Housings Removed from Service

International Nuclear Information System (INIS)

Cumblidge, Stephen E.; Doctor, Steven R.; Schuster, George J.; Harris, Robert V.; Crawford, Susan L.

2006-01-01

Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are being performed to assess the effectiveness of nondestructive examination (NDE) techniques on removed-from-service control rod drive mechanism (CRDM) nozzles and the associated J-groove attachment welds. This work is being performed to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of NDE techniques such as ultrasonic testing (UT), eddy current testing (ET), and visual testing (VT) as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. The basic NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory-based NDE methods were employed to conduct inspections of the CRDM assemblies, with particular emphasis on the J-groove weld and buttering. This paper describes the NDE measurements that were employed on the two CRDMs to detect and characterize the indications and the analysis of these indications. The two CRDM assemblies were removed from service from the North Anna 2 vessel head, including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material. One nozzle contains suspected PWSCC, based on in-service inspection data; the second contains evidence suggesting through-wall leakage, although this was unconfirmed. A destructive test plan is being developed to directly characterize the indications found using nondestructive testing. The results of this destructive testing will be included when the destructive testing is completed.

Synthesis of oxocarbon-encapsulated gold nanoparticles with blue-shifted localized surface plasmon resonance by pulsed laser ablation in water with CO2 absorbers

Science.gov (United States)

Del Rosso, T.; Rey, N. A.; Rosado, T.; Landi, S.; Larrude, D. G.; Romani, E. C.; Freire Junior, F. L.; Quinteiro, S. M.; Cremona, M.; Aucelio, R. Q.; Margheri, G.; Pandoli, O.

2016-06-01

Colloidal suspensions of oxocarbon-encapsulated gold nanoparticles have been synthesized in a one-step procedure by pulsed-laser ablation (PLA) at 532 nm of a solid gold target placed in aqueous solution containing CO2 absorbers, but without any stabilizing agent. Multi-wavelength surface enhanced Raman spectroscopy allows the identification of adsorbed amorphous carbon and graphite, Au-carbonyl, Au coordinated CO2-derived bicarbonates/carbonates and hydroxyl groups around the AuNPs core. Scanning electron microscopy, energy dispersive x-ray analysis and high resolution transmission electron microscopy highlight the organic shell structure around the crystalline metal core. The stability of the colloidal solution of nanocomposites (NCs) seems to be driven by solvation forces and is achieved only in neutral or basic pH using monovalent hydroxide counter-ions (NaOH, KOH). The NCs are characterized by a blue shift of the localized surface plasmon resonance (LSPR) band typical of metal-ligand stabilization by terminal π-back bonding, attributed to a core charging effect caused by Au-carbonyls. Total organic carbon measurements detect the final content of organic carbon in the colloidal solution of NCs that is about six times higher than the value of the water solution used to perform PLA. The colloidal dispersions of NCs are stable for months and are applied as analytical probes in amino glycoside antibiotic LSPR based sensing.

Ultra-small plutonium oxide nanocrystals: an innovative material in plutonium science.

Science.gov (United States)

Hudry, Damien; Apostolidis, Christos; Walter, Olaf; Janssen, Arne; Manara, Dario; Griveau, Jean-Christophe; Colineau, Eric; Vitova, Tonya; Prüssmann, Tim; Wang, Di; Kübel, Christian; Meyer, Daniel

2014-08-11

Apart from its technological importance, plutonium (Pu) is also one of the most intriguing elements because of its non-conventional physical properties and fascinating chemistry. Those fundamental aspects are particularly interesting when dealing with the challenging study of plutonium-based nanomaterials. Here we show that ultra-small (3.2±0.9 nm) and highly crystalline plutonium oxide (PuO2 ) nanocrystals (NCs) can be synthesized by the thermal decomposition of plutonyl nitrate ([PuO2 (NO3 )2 ]⋅3 H2 O) in a highly coordinating organic medium. This is the first example reporting on the preparation of significant quantities (several tens of milligrams) of PuO2 NCs, in a controllable and reproducible manner. The structure and magnetic properties of PuO2 NCs have been characterized by a wide variety of techniques (powder X-ray diffraction (PXRD), X-ray absorption fine structure (XAFS), X-ray absorption near edge structure (XANES), TEM, IR, Raman, UV/Vis spectroscopies, and superconducting quantum interference device (SQUID) magnetometry). The current PuO2 NCs constitute an innovative material for the study of challenging problems as diverse as the transport behavior of plutonium in the environment or size and shape effects on the physics of transuranium elements. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Norwegian or Crusted Sarcoptic Mange in Two Leishmanial Dogs.

Science.gov (United States)

Kaltsogianni, Flora; Farmaki, Rania; Koutinas, Alexander F

Norwegian or crusted scabies (N/CS) is a rare skin disease with very few cases reported in the dog or the cat. Two adult, stray dogs were admitted in our clinic with a generalized, multifocal to diffuse and nonpruritic dermatitis that was characterized by severe crusting, scaling, and ulceration. In both instances, leishmaniosis and N/CS were diagnosed by immunofluorescent antibody test serology, lymph node cytology, and skin scrapings in which high numbers of Sarcoptes mites were found. The combination of miticidal and antileishmanial treatment, supported by topical treatment and nutritional support, resulted in the complete resolution of the skin lesions and spectacular improvement of the body condition in both cases. Dog 1 eventually died from end-stage kidney disease attributed to leishmaniosis-associated glomerulonephritis, whereas the also proteinuric dog 2 remains clinically healthy. The manifestation of the rare type of N/CS in these dogs could be attributed to cell-mediated immunosuppression, which was most likely induced by leishmaniosis and malnutrition. The necessity of searching for leishmaniosis in those scabietic cases, especially in the endemic areas of leishmaniosis, is strongly recommended.

Synthesis of Copper-Antimony-Sulfide Nanocrystals for Solution-Processed Solar Cells.

Science.gov (United States)

Suehiro, Satoshi; Horita, Keisuke; Yuasa, Masayoshi; Tanaka, Tooru; Fujita, Katsuhiko; Ishiwata, Yoichi; Shimanoe, Kengo; Kida, Tetsuya

2015-08-17

The p-type nanocrystals (NCs) of copper-based chalcogenides, such as CuInSe2 and Cu2ZnSnS4, have attracted increasing attention in photovoltaic applications due to their potential to produce cheap solution-processed solar cells. Herein, we report the synthesis of copper-antimony-sulfide (CAS) NCs with different crystal phases including CuSbS2, Cu3SbS4, and Cu12Sb4S13. In addition, their morphology, crystal phase, and optical properties were characterized using transmission electron microscopy, X-ray diffractometry, UV-vis-near-IR spectroscopy, and photoemission yield spectroscopy. The morphology, crystal phase, and electronic structure were significantly dependent on the chemical composition in the CAS system. Devices were fabricated using particulate films consisting of CAS NCs prepared by spin coating without a high-temperature treatment. The CAS NC-based devices exhibited a diode-like current-voltage characteristic when coupled with an n-type CdS layer. In particular, the CuSbS2 NC devices exhibited photovoltaic responses under simulated sunlight, demonstrating its applicability for use in solution-processed solar cells.

Synthesis, Photophysical and Electrochemical Properties of a Mixed Bipyridyl-Phenanthrolyl Ligand Ru(II Heteroleptic Complex Having trans-2-Methyl-2-butenoic Acid Functionalities

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2011-09-01

Full Text Available In this work, two ligands: 4-(trans-2-Methyl-2-butenoic acid-2,2'-bipyridine (L1 and 5-(trans-2-methyl-2-butenoic acid-1,10-phenanthroline (L2, with the corresponding mixed-ligand heteroleptic Ru(II complex were synthesized and characterized by FT-IR, 1H-, 13C-NMR spectroscopy and elemental analysis. The influence of the mixed functionalized polypyridyl ruthenium(II complex on the photophysical and electrochemical properties were investigated and compared to individual single-ligand homoleptic complexes. Interestingly, the mixed-ligand complex formulated as [RuL1L2(NCS2] exhibits broad and intense metal-to-ligand charge transfer (MLCT absorption with a high molar extinction coefficient (λmax = 514 nm, ε = 69,700 M−1 cm−1, better than those of individual single-ligand complexes, [Ru(L12(NCS2] and [Ru(L22(NCS2], and a strong photoluminescence intensity ratio in the red region at λem = 686 nm. The electrochemical properties of the complex indicated that the redox processes are ligand-based.

A gold electrode modified with silver oxide nanoparticle decorated carbon nanotubes for electrochemical sensing of dissolved ammonia

International Nuclear Information System (INIS)

Rahman, Mohammed M.; Asiri, Abdullah M.; Balkhoyor, Hasan B.; Marwani, Hadi M.

2016-01-01

We have prepared silver oxide nanoparticles with a diameter of ∼ 15 nm and decorated with carbon nanotube nanocomposites (Ag_2O/CNT NCs) by a facile wet chemical method using reducing agents in alkaline medium. These NCs were characterized by UV/vis, FTIR and energy dispersive X-ray spectroscopy, by X-ray powder diffraction and field emission scanning electron microscopy. The NCs were then deposited on a flat gold electrode with the help of a conducting binder to result in an electrochemical sensor for aqueous ammonia using the I-V technique. Response is based on surface oxidation of ammonium hydroxide with electrode-adsorbed oxygen to form nitrogen oxide, these simultaneously liberating free electrons in the conduction band. Sensor features include a sensitivity of 32.856 μA.μM"-"1.cm"-"2, a low detection limit (1.3 pM at a signal to noise ratio of 3), reliability, reproducibility, ease of integration, and long term stability. The response to dissolved ammonia is linear (r"2: 0.9778) over the 0.01 nM to 0.1 mM concentration range. (author)

Strong enhancement of the electrochemiluminescence of luminol by AuAg and PtAg alloy nanoclusters, and its sensitization by phenolic artificial oestrogens

International Nuclear Information System (INIS)

Wang, Ke; Tu, Yifeng; Wei, Xiuhua

2014-01-01

This paper reports on the synthesis of AuAg and PtAg alloy nanoclusters (NCs) and their enhancement effect on the electrochemiluminescence (ECL) of luminol. The conditions of synthesis were optimized, and the structure and properties of the NCs were characterized by X-ray diffraction, transmission electron microscopy, electrochemistry, and optical spectroscopy. The NCs are found to intensify (by up to 20 times) the ECL of luminol in solution of pH 8.5. This finding can largely extend the useful pH range of the ECL of luminol. The enhanced ECL is strongly affected by oxygen and hydrogen peroxide, and the mechanism of enhancement is attributed to the accelerated production of reactive oxygen species. The enhanced ECL is also affected by phenolic artificial estrogens, and this was used for their determination with detection limits as low as 700 pg L −1 (with AuAg) and 1.6 ng L −1 (with PtAg). The method was applied to the determination of such estrogens in egg samples using diethylstilbestrol as a reference substance. (author)

Melamine dependent fluorescence of glutathione protected gold nanoclusters and ratiometric quantification of melamine in commercial cow milk and infant formula

Science.gov (United States)

Kalaiyarasan, Gopi; K, Anusuya; Joseph, James

2017-10-01

Companies processing the milk for the further production of powdered infant formulation normally check the protein level through a test measuring nitrogen content. The addition of melamine which is a nitrogen-rich organic chemical in milk increases the nitrogen content and therefore enhances its apparent protein content. However, the melamine causes kidney failure and death owing to the formation of kidney stone. Thus the determination of melamine in humans and milk products have gained great significance in recent years. The gold nanoclusters (AuNCs) have attracting features due to its unique electronic and optical properties like fluorescence nature. Therefore one can use AuNCs in the field of biosensor, bio-imaging, nanobiotechnology, drug delivery, diagnosis etc. We report, a new ratiometric nanosensor established for the selective and sensitive detection of melamine based optical sensing using glutathione stabilized AuNCs. The AuNCs were characterized by high-resolution transmission electron microscopy (HR-TEM), UV-visible and Photoluminescence (PL) spectroscopic techniques. In the presence of melamine, the PL intensity at 430 nm increases owing to the (turn-on) enhancement in fluorescence, whereas PL intensity at 610 nm decreases due to the melamine-induced aggregation and subsequent aggregation-enhanced emission quenching. The observed changes were ascribed to the hydrogen bonding interaction between melamine and AuNCs, which led to the aggregation of the nanoclusters. This was confirmed by dynamic light scattering and HR-TEM measurements. The present probe showed an extreme selectivity towards the determination of 28.2 μM melamine in the presence of 100-fold excess of common interfering molecules such as Alanine, Glycine, Glucose, Cystine etc. The proposed method was successfully applied to determine melamine in cow milk.

Study on thermal, mechanical and adsorption properties of amine-functionalized MCM-41/PMMA and MCM-41/PS nanocomposites prepared by ultrasonic irradiation.

Science.gov (United States)

Mohammadnezhad, Gholamhossein; Abad, Saeed; Soltani, Roozbeh; Dinari, Mohammad

2017-11-01

In this study, two common industrial polymers, poly(methyl methacrylate) (PMMA) and polystyrene (PS), were incorporated into amine-functionalized MCM-41 mesoporous silica as reinforcement agents via an ultrasonic assisted method as a facile, fast, eco-friendly, and versatile synthetic tool. Amino functionalization of MCM-41 were performed by 3-aminopropyl triethoxysilane as a coupling agent and it is denoted as APTS-MCM-41. The obtained nanocomposites (NCs), APTS-MCM-41/PMMA and APTS-MCM-41/PS, were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning and transmission electron microscopies (SEM and TEM), and thermogravimetric analysis (TGA). Their mechanical properties were also probed via stress-strain curves and improved tensile properties were observed in the NCs relative to the neat polymers. Additionally, APTS-MCM-41/PMMA exhibited better mechanical properties than APTS-MCM-41/PS. Sorption studies were carried out on the two NCs and the effect of different process parameters, namely, pH, contact time, and initial Cd(II) concentration investigated in batch mode. Pseudo-second order and intraparticle diffusion models explain the Cd(II) kinetics more effectively for APTS-MCM-41/PMMA and APTS-MCM-41/PS, respectively. The adsorption isotherm data fitted well to Langmuir isotherm for both NCs and the maximum monolayer adsorption capacities were found to be 24.75mg/g and 10.42mg/g for APTS-MCM-41/PMMA and APTS-MCM-41/PS, respectively. The results demonstrate that the NCs show potential for use in adsorption of heavy metal ion such as Cd(II) from aqueous media. Copyright © 2017 Elsevier B.V. All rights reserved.

Fighting cancer with nanomedicine---drug-polyester nanoconjugates for targeted cancer therapy

Science.gov (United States)

Yin, Qian

The aim of my Ph. D. research is to develop drug-polyester nanoconjugates (NCs) as a novel translational polymeric drug delivery system that can successfully evade non-specific uptake by reticuloendothelial system (RES) and facilitate targeted cancer diagnosis and therapy. By uniquely integrating well-established chemical reaction-controlled ring opening polymerization (ROP) with nanoprecipitation technique, I successfully developed a polymeric NC system based on poly(lactic acid) and poly(O-carboxyanhydrides) (OCA) that allows for the quantitative loading and controlled release of a variety of anticancer drugs. The developed NC system could be easily modified with parmidronate, one of bisphosphonates commonly used as the treatment for disease characterized by osteolysis, to selectively deliver doxorubicin (Doxo) to the bone tissues and substantially to improve their therapeutic efficiency in inhibiting the growth of osteosarcoma in both murine and canine models. More importantly, the developed NCs could avidly bind to human serum albumin, a ubiquitous protein in the blood, to bypass the endothelium barrier and penetrate into tumor tissues more deeply and efficiently. When compared with PEGylated NCs, these albumin-bound NCs showed significantly reduced accumulation in RES and enhanced tumor accumulation, which consequently contributed to higher their tumor inhibition capabilities. In addition, the developed NC system allows easy incorporation of X-ray computed tomography (CT) contrast agents to largely facilitate personalized therapy by improving diagnosis accuracy and monitoring therapeutic efficacy. Through the synthetic and formulation strategy I developed, a large quantity (grams or larger-scale) of drug-polyester NCs can be easily obtained, which can be used as a model drug delivery system for fundamental studies as well as a real drug delivery system for disease treatment in clinical settings.

Chitosan-hyaluronan/nano chondroitin sulfate ternary composite sponges for medical use.

Science.gov (United States)

Anisha, B S; Sankar, Deepthi; Mohandas, Annapoorna; Chennazhi, K P; Nair, Shantikumar V; Jayakumar, R

2013-02-15

In this work chitosan-hyaluronan composite sponge incorporated with chondroitin sulfate nanoparticle (nCS) was developed. The fabrication of hydrogel was based on simple ionic cross-linking using EDC, followed by lyophilization to obtain the composite sponge. nCS suspension was characterized using DLS and SEM and showed a size range of 100-150 nm. The composite sponges were characterized using SEM, FT-IR and TG-DTA. Porosity, swelling, biodegradation, blood clotting and platelet activation of the prepared sponges were also evaluated. Nanocomposites showed a porosity of 67% and showed enhanced swelling and blood clotting ability. Cytocompatibility and cell adhesion studies of the sponges were done using human dermal fibroblast (HDF) cells and the nanocomposite sponges showed more than 90% viability. Nanocomposite sponges also showed enhanced proliferation of HDF cells within two days of study. These results indicated that this nanocomposite sponges would be a potential candidate for wound dressing. Copyright © 2012 Elsevier Ltd. All rights reserved.

The roles of the liver and pancreas in renal nutcracker syndrome

Energy Technology Data Exchange (ETDEWEB)

Yun, Seong Jong, E-mail: zoomknight@naver.com [Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Kangdong-gu, Seoul 134-727 (Korea, Republic of); Department of Radiology, Graduate School of Medicine, Kyung Hee University, Hoegi-dong, Dongdaemun-gu, Seoul 130-701 (Korea, Republic of); Nam, Deok Ho, E-mail: namjindan@daum.net [Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Kangdong-gu, Seoul 134-727 (Korea, Republic of); Ryu, Jung Kyu, E-mail: oddie2@naver.com [Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Kangdong-gu, Seoul 134-727 (Korea, Republic of); Kim, Ji Su, E-mail: js830808@hanmail.net [Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Kangdong-gu, Seoul 134-727 (Korea, Republic of)

2014-10-15

Graphical abstract: - Highlights: • The presence of the liver and pancreas may influence NCS by compressing SMA against the aorta. • The presence of the liver and pancreas at the level of the LRV is not yet recognized as an independent factor for NCS but should be. • The presence of the liver and the pancreas may allow clinicians to identify NCS patients and may influence the choice of treatment options. - Abstract: Introduction: To assess the frequency and significance of presence of the liver and pancreas at the left renal vein (LRV) level in patients with suspected renal nutcracker syndrome (NCS). Materials and methods: We included 101 patients with hematuria who underwent urography three-dimensional CT between April 2009 and November 2013. These patients were divided into NCS (n = 25) and non-NCS (n = 76) patients according to the following CT criteria: (1) the presence of beak sign and (2) hilar-aortomesenteric left renal vein diameter ratio >4. Patients were grouped according to the presence of the liver and pancreas at the LRV: group LP (both liver and pancreas), group L (only liver), group P (only pancreas), and group O (neither liver nor pancreas). The difference in the frequencies of groups was analyzed between NCS and non-NCS patients. Multivariate analysis was used to determine the independent factors between NCS and non-NCS patients. Results: The frequencies of group LP, group L, group P, and group O in NCS vs. non-NCS were 88% vs. 5.3% (p < 0.001), 4.0% vs. 2.6% (p = 0.75), 4.0% vs. 11.8% (p = 0.45), 4.0% vs. 80.3% (p < 0.001), respectively. Multivariate analysis demonstrated that group was a predictor for differential diagnosis between NCS and non-NCS (p = 0.022), and group LP was an independent factor for the presence of NCS (odds ratio, 43.8; 95% confidence interval, 3.8–500.3; p < 0.002; reference, group O). Conclusion: The presence of the liver and pancreas at the level of the LRV was frequently found in NCS and was the independent factor

The roles of the liver and pancreas in renal nutcracker syndrome

International Nuclear Information System (INIS)

Yun, Seong Jong; Nam, Deok Ho; Ryu, Jung Kyu; Kim, Ji Su

2014-01-01

Graphical abstract: - Highlights: • The presence of the liver and pancreas may influence NCS by compressing SMA against the aorta. • The presence of the liver and pancreas at the level of the LRV is not yet recognized as an independent factor for NCS but should be. • The presence of the liver and the pancreas may allow clinicians to identify NCS patients and may influence the choice of treatment options. - Abstract: Introduction: To assess the frequency and significance of presence of the liver and pancreas at the left renal vein (LRV) level in patients with suspected renal nutcracker syndrome (NCS). Materials and methods: We included 101 patients with hematuria who underwent urography three-dimensional CT between April 2009 and November 2013. These patients were divided into NCS (n = 25) and non-NCS (n = 76) patients according to the following CT criteria: (1) the presence of beak sign and (2) hilar-aortomesenteric left renal vein diameter ratio >4. Patients were grouped according to the presence of the liver and pancreas at the LRV: group LP (both liver and pancreas), group L (only liver), group P (only pancreas), and group O (neither liver nor pancreas). The difference in the frequencies of groups was analyzed between NCS and non-NCS patients. Multivariate analysis was used to determine the independent factors between NCS and non-NCS patients. Results: The frequencies of group LP, group L, group P, and group O in NCS vs. non-NCS were 88% vs. 5.3% (p < 0.001), 4.0% vs. 2.6% (p = 0.75), 4.0% vs. 11.8% (p = 0.45), 4.0% vs. 80.3% (p < 0.001), respectively. Multivariate analysis demonstrated that group was a predictor for differential diagnosis between NCS and non-NCS (p = 0.022), and group LP was an independent factor for the presence of NCS (odds ratio, 43.8; 95% confidence interval, 3.8–500.3; p < 0.002; reference, group O). Conclusion: The presence of the liver and pancreas at the level of the LRV was frequently found in NCS and was the independent factor

Synthesis, structure, spectral characterization and thermal analysis of the tetraaquabis (isothiocyanato-κN) cobalt (II)-bis(caffeine)-tetrahydrate complex

Science.gov (United States)

EL Hamdani, H.; EL Amane, M.; Duhayon, C.

2018-04-01

The complex 2(C8H10N4O2).[Co(H2O)4(NCS)2].4H2O was prepared in the water-ethanol solution at room temperature and characterized by the single crystal X-ray diffraction analysis, 1H, 13C NMR, TGA/DTA and IR spectroscopy. This complex was crystallized in the monoclinic system (P 21/c). The unit cell parameters are a = 10.65854 (19) A°, b = 8.16642 (14) A°, c = 18.0595 (3) A° with β = 96.4701° (15). The cobalt (II) cation is coordinated by four oxygen atoms of the water molecules and two nitrogen in isothiocyanato a trans octahedral geometry, stabilized by hydrogen bonds with caffeine molecule and free water molecule, The intermolecular hydrogen bonds: Osbnd H⋯N, Osbnd H⋯O, Csbnd H⋯S, π···π interactions are together playing a vital role in the stabilization of the crystal packing.

BASE/X business agility through cross-organizational service engineering : the business and service design approach developed in the CoProFind project

NARCIS (Netherlands)

Grefen, P.W.P.J.; Lüftenegger, E.R.; Linden, van der E.; Weisleder, C.A.

2013-01-01

Many business domains are currently characterized by a move from an asset-orientation to a service-orientation: customers recognize that business value is not in owning assets, but in using the services offered by assets (which they do not need to own). This creates service-dominant business

Library of Norcoclaurine Synthases and Their Immobilization for Biocatalytic Transformations.

Science.gov (United States)

Lechner, Horst; Soriano, Pablo; Poschner, Roman; Hailes, Helen C; Ward, John M; Kroutil, Wolfgang

2018-03-01

Norcoclaurine synthases (NCS), catalyzing a Pictet-Spengler reaction in plants as one of the first enzymes in the biosynthetic benzylisoquinoline pathway, are investigated for biocatalytic transformations. The library of NCS available is extended by two novel NCSs from Argemone mexicana (AmNCS1, AmNCS2) and one new NCS from Corydalis saxicola (CsNCS); furthermore, it is shown that the NCS from Papaver bracteatum (PbNCS) is a highly productive catalyst leading to the isoquinoline product with up to >99% e.e. Under certain conditions lyophilized whole Escherichia coli cells containing the various overexpressed NCS turned out to be suitable catalysts. The reaction using dopamine as substrate bears several challenges such as the spontaneous non-stereoselective background reaction and side reactions. The PbNCS enzyme is successfully immobilized on various carriers whereby EziG3 proved to be the best suited for biotransformations. Dopamine showed limited stability in solution resulting in the coating of the catalyst over time, which could be solved by the addition of ascorbic acid (e.g., 1 mg ml -1 ) as antioxidant. © 2017 The Authors. Biotechnology Journal Published by Wiley-VCH Verlag GmbH &Co. KGaA.

Structural and optical properties of Na doped ZnO nanocrystals: Application to solar photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Tabib, Asma; Bouslama, Wiem [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Sieber, Brigitte; Addad, Ahmed [UMET, UMR, CNRS 8207, Université Lille 1, 59665 Villeneuve d’Ascq Cédex (France); Elhouichet, Habib, E-mail: habib.elhouichet@fst.rnu.tn [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Département de Physique, Faculté des Sciences de Tunis, University of Tunis, ElManar 2092 (Tunisia); Férid, Mokhtar [Laboratoire de Physico-Chimie des Matériaux Minéraux et leurs Applications, Centre National de Recherches en Sciences des Matériaux, B.P. 95 Hammam-Lif, 2050 (Tunisia); Boukherroub, Rabah [Institut d’Electronique de Microélectronique et de Nanotechnologie (IEMN), UMR, CNRS, 8520 Avenue Pointcarré, BP 60069, 59652 Villeneuve d’Ascq (France)

2017-02-28

Highlights: • Na doped ZnO nanocrystals were prepared via sol–gel method. • A substitution of Zn{sup 2+} by Na{sup +} was demonstrated. • Low Na concentration induces higher photocatalytic activity under solar irradiation. • Oxygen vacancies guided the processes of charge separation. - Abstract: Na doped ZnO nanocrystals (NCs) were successfully produced by sol–gel process and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), Raman scattering, UV–vis diffuse reflectance spectroscopy and photoluminescence (PL). XRD analysis indicated that all the prepared samples present pure hexagonal wurtzite structure without any Na related phases. The lattice distortion, calculated using Williamson hall equation, induces stress and a reduction of NCs size from 71.4 to 24.5 nm. TEM images showed NCs with hexagonal shape and a rather uniform size distribution. The selected area electron diffraction (SAED) patterns confirmed the high crystal quality along the 〈101〉 direction and is consistent with the hexagonal wurtzite structure of ZnO. The Raman spectra are dominated by E{sub 2}{sup high} mode of ZnO. High Na doping shows the occurrence of anomalous local vibrational Raman modes close to 270 and 513 cm{sup −1} that are related to intrinsic host lattice defects and distortion, respectively. Optical band gap was found to vary with Na content. Photoluminescence (PL) spectra indicate the presence of a high density of defects in ZnO NCs which are mainly oxygen vacancies. Finally, the obtained NCs were used as a photocatalyst to degrade Rhodamine B (RhB) in solution, under solar irradiation. Na doping enhances the photocatalytic activity of ZnO NCs till an optimum concentration of 0.5% where a full degradation was observed after 120 min of sun light irradiation. Furthermore, this sample presents a good cycling stability and reusability. Based on scavangers test, it was found that both superoxide and

Enabling Routes as Context in Mobile Services

DEFF Research Database (Denmark)

Brilingaite, Agne; Jensen, Christian Søndergaard; Zokaite, Nora

2004-01-01

With the continuing advances in wireless communications, geo-positioning, and portable electronics, an infrastructure is emerging that enables the delivery of on-line, location-enabled services to very large numbers of mobile users. A typical usage situation for mobile services is one characterized...... by a small screen and no keyboard, and by the service being only a secondary focus of the user. It is therefore particularly important to deliver the "right" information and service at the right time, with as little user interaction as possible. This may be achieved by making services context aware.Mobile...

Using benefit indicators to evaluate ecosystem services resulting from restoration

Science.gov (United States)

Ecological restoration can reestablish ecosystem services that provide valuable social and environmental benefits. Final ecosystem goods and services (FEGS) are the goods and services that directly benefit people. Explicitly identifying the people who benefit and characterizing w...

Assessing Freshwater Ecosystem Service Risk over Ecological, Socioeconomic, and Cultural Gradients: Problem Space Characterization and Methodology

Science.gov (United States)

Harmon, T. C.; Villamizar, S. R.; Conde, D.; Rusak, J.; Reid, B.; Astorga, A.; Perillo, G. M.; Piccolo, M. C.; Zilio, M.; London, S.; Velez, M.; Hoyos, N.; Escobar, J.

2014-12-01

Freshwater ecosystems and the services they provide are under increasing anthropogenic pressure at local (e.g., irrigation diversions, wastewater discharge) and global scales (e.g., climate change, global trading). The impact depends on an ecosystem's sensitivity, which is determined by its geophysical and ecological settings, and the population and activities in its surrounding watershed. Given the importance of ecosystem services, it is critical that we improve our ability to identify and understand changes in aquatic ecosystems, and translate them to risk of service loss. Furthermore, to inspire changes in human behavior, it is equally critical that we learn to communicate risk, and pose risk mitigation strategies, in a manner acceptable to a broad spectrum of stakeholders. Quantifying the nature and timing of the risk is difficult because (1) we often fail to understand the connection between anthropogenic pressures and the timing and extent of ecosystem changes; and (2) the concept of risk is inherently coupled to human perception, which generally differs with cultural and socio-economic conditions. In this study, we endeavor to assess aquatic ecosystem risks across an international array of six study sites. The challenge is to construct a methodology capable of capturing the marked biogeographical, socioeconomic, and cultural differences among the sites, which include: (1) Muskoka River watershed in humid continental Ontario, Canada; (2) Lower San Joaquin River, an impounded snow-fed river in semi-arid Central California; (3) Ciénaga Grande de Santa Marta, a tropical coastal lagoon in Colombia; (4) Senguer River basin in the semi-arid part of Argentina; (5) Laguna de Rocha watershed in humid subtropical Uruguay; and (6) Palomas Lake complex in oceanic Chilean Patagonia. Results will include a characterization of the experimental gradient over the six sites, an overview of the risk assessment methodology, and preliminary findings for several of the sites.

Nanocaged platforms: modification, drug delivery and nanotoxicity. Opening synthetic cages to release the tiger.

Science.gov (United States)

Karimi, Mahdi; Zangabad, Parham Sahandi; Mehdizadeh, Fatemeh; Malekzad, Hedieh; Ghasemi, Alireza; Bahrami, Sajad; Zare, Hossein; Moghoofei, Mohsen; Hekmatmanesh, Amin; Hamblin, Michael R

2017-01-26

Nanocages (NCs) have emerged as a new class of drug-carriers, with a wide range of possibilities in multi-modality medical treatments and theranostics. Nanocages can overcome such limitations as high toxicity caused by anti-cancer chemotherapy or by the nanocarrier itself, due to their unique characteristics. These properties consist of: (1) a high loading-capacity (spacious interior); (2) a porous structure (analogous to openings between the bars of the cage); (3) enabling smart release (a key to unlock the cage); and (4) a low likelihood of unfavorable immune responses (the outside of the cage is safe). In this review, we cover different classes of NC structures such as virus-like particles (VLPs), protein NCs, DNA NCs, supramolecular nanosystems, hybrid metal-organic NCs, gold NCs, carbon-based NCs and silica NCs. Moreover, NC-assisted drug delivery including modification methods, drug immobilization, active targeting, and stimulus-responsive release mechanisms are discussed, highlighting the advantages, disadvantages and challenges. Finally, translation of NCs into clinical applications, and an up-to-date assessment of the nanotoxicology considerations of NCs are presented.

Fairness as a QoS Measure for Web Services

Directory of Open Access Journals (Sweden)

Stefano Bistarelli

2009-06-01

Full Text Available Service Oriented Architectures (SOAs are component-based architectures, characterized by reusability, modularization and composition, usually offered by HTTP (web services and often equipped with a Quality of Services (QoS measure. In order to guarantee the fairness property to each client requesting a service, we propose a fair version of the (Soft Concurrent Constraint language to deal with the negotiation phases of the Service Level Agreement (SLA protocol.

Capability of ds-DNA duplex structure in growing fluorescent silver nanoclusters

International Nuclear Information System (INIS)

Wu, Tao; Lin, Fan; Hu, Yuehua; Wang, Ying; Zhou, Xiaoshun; Shao, Yong

2016-01-01

Silver nanoclusters (AgNCs) have attracted wide interests in variant fields due to their easy synthesis and practical tunability in fluorescence properties. DNA has been generally used as the host to grow AgNCs due to the sequence-dependent fluorescence behavior. Actually, in such DNA, various ss-DNA segments that are structurally confined by the rigid ds-DNA counterparts have been used as the AgNCsГ—Ві growth sites. However, whether the ds-DNA structure plays somewhat role in AgNCsГ—Ві creation has not been well elucidated. Herein, we found that ds-DNA can also accommodate the growth of fluorescent AgNCs. The fluorescent AgNCs grown on ds-DNA should be separated each other and the G/C base pairs with right context sequences are the growth sites of fluorescent AgNCs. The intermediate A/T base pair among the continuous G/C ones seems to quench the growth of fluorescent AgNCs. For the repeat sequences, the fluorescence band position of AgNCs is not changed but the intensity is enhanced upon increasing the ds-DNA length, which is different from the results obtained with the previously reported ss-DNAs. AgNCs should be grown on the ds-DNA major groove, as convinced by the cytosine methylation experiment. Our work demonstrates that besides the ss-DNA role in defining AgNCs, one should also take into account the critical role of the ds-DNA segment in tuning the AgNCsГ—Ві fluorescence property.

Syntheses, spectroscopic characterization, crystal structure and natural rubber vulcanization activity of new disulfides derived from sulfonyldithiocarbimates

Science.gov (United States)

Alves, Leandro de Carvalho; Rubinger, Mayura Marques Magalhães; Tavares, Eder do Couto; Janczak, Jan; Pacheco, Elen Beatriz Acordi Vasques; Visconte, Leila Lea Yuan; Oliveira, Marcelo Ribeiro Leite

2013-09-01

The compounds (Bu4N)2[(4-RC6H4SO2NCS2)2] [Bu4N = tetrabutylammonium cation; R = H (1), F (2), Cl (3) and Br (4)] and (Ph4P)2[(4-RC6H4SO2NCS2)2]ṡH2O [Ph4P = tetraphenylphosphonium cation and R = I (5)] were synthesized by the reaction of the potassium dithiocarbimates (4-RC6H4SO2NCS2K2ṡ2H2O) with I2 and Bu4NBr or Ph4PCl. The IR data were consistent with the formation of the dithiocarbimatodisulfides anions. The NMR spectra showed the expected signals for the cations and anions in a 2:1 proportion. The structures of compounds 1-5 were determined by the single crystal X-ray diffraction. The compounds 2, 3 and 4 are isostructural and crystallise in the centrosymmetric space group C2/c of the monoclinic system. Compound 1 crystallises in the monoclinic system in the space group of P21/n and the compound 5 crystallises in the centrosymmetric space group P-1 of the triclinic system. The complex anions of compounds 2, 3 and 4 exhibit similar conformations having twofold symmetry, while in 1 and 5 the anions exhibit C1 symmetry. The activity of the new compounds in the vulcanization of the natural rubber was evaluated and compared to the commercial accelerators ZDMC, TBBS and TMTD. These studies confirm that the sulfonyldithiocarbimato disulfides anions are new vulcanization accelerators, being slower than the commercial accelerators, but producing a greater degree of crosslinking, and scorch time values compatible with good processing safety for industrial applications. The mechanical properties, stress and tear resistances were determined and compared to those obtained with the commercial accelerators.

[Toxicological evaluation of nanosized colloidal silver, stabilized with polyvinylpyrrolidone. I. Characterization of nanomaterial, integral, hematological parameters, level of thiol compounds and liver cell apoptosis].

Science.gov (United States)

Shumakova, A A; Shipelin, V A; Sidorova, Yu S; Trushina, E N; Mustafina, O K; Pridvorova, S M; Gmoshinsky, I V; Khotimchenko, S A

2015-01-01

Nano-sized colloidal silver (NCS) is currently one of the most widely used nanomaterials in medicine and consumer’s products. Nanoparticles (NPs) of silver, in addition to the direct exposition through products may expose human via various environmental objects. The aim of the study is to assess the safe doses of silver NP received orally. The investigated NCS contained silver NPs with diameter of 10–60 nm, predominantly with a nearly spherical form stabilized with polyvinylpyrrolidone (PVP). The experiment was performed during 92 days in 5 groups of male Wistar rats (n=15 in each group), receiving a balanced semisynthetic diet. Animal of group 1 (control) received vehicle (deionized water) intragastrically for 30 days and then with food, groups from 2nd to 4th – PVP and groups from 3rd to 5th NCS, in doses respectively, 0.1; 1.0 and 10 mg/kg body weight (b.w.) in terms of silver. The dose of PVP in groups from 2nd to 5th did not differ, amounting to 200 mg/kg b.w. During the experiment, the weight gain, skin condition, activity, stool, cognitive function were assessed. At the end of the feeding period weight of internal organs, intestinal wall permeability to protein macromolecules, liver thiols, standard values of blood erythrocytes, leukocytes and platelets, hepatocyte apoptosis by flow cytometry were studied. These results suggest that in terms of weight gain, lung relative mass, average erythrocyte volume, hemoglobin content and concentration in erythrocytes, the relative proportion of lymphocytes and neutrophils adverse changes have been observed at a dose of 10 mg NPs per kg of b.w. At lower levels of exposure (0.1 and 1.0 mg/kg b.w.) some specific changes were also observed (in terms of thiols pool in liver, cognitive function, relative abundance of monocytes, the number of dead hepatocytes), which, however, did not possess an unambiguous dependence on the dose. Possible mechanisms of the toxic action of the NCS have been discussed.

Core-shell nanocarriers with high paclitaxel loading for passive and active targeting

Science.gov (United States)

Jin, Zhu; Lv, Yaqi; Cao, Hui; Yao, Jing; Zhou, Jianping; He, Wei; Yin, Lifang

2016-06-01

Rapid blood clearance and premature burst release are inherent drawbacks of conventional nanoparticles, resulting in poor tumor selectivity. iRGD peptide is widely recognized as an efficient cell membrane penetration peptide homing to αVβ3 integrins. Herein, core-shell nanocapsules (NCs) and iRGD-modified NCs (iRGD-NCs) with high drug payload for paclitaxel (PTX) were prepared to enhance the antitumor activities of chemotherapy agents with poor water solubility. Improved in vitro and in vivo tumor targeting and penetration were observed with NCs and iRGD-NCs; the latter exhibited better antitumor activity because iRGD enhanced the accumulation and penetration of NCs in tumors. The NCs were cytocompatible, histocompatible, and non-toxic to other healthy tissues. The endocytosis of NCs was mediated by lipid rafts in an energy-dependent manner, leading to better cytotoxicity of PTX against cancer cells. In contrast with commercial product, PTX-loaded NCs (PTX-NCs) increased area under concentration-time curve (AUC) by about 4-fold, prolonged mean resident time (MRT) by more than 8-fold and reduced the elimination rate constant by greater than 68-fold. In conclusion, the present nanocarriers with high drug-loading capacity represent an efficient tumor-targeting drug delivery system with promising potential for cancer therapy.

State as a Service : Towards Stateful Cloud Services

OpenAIRE

Alnoor, Ahmadullah

2012-01-01

Cloud ERP or Enterprise Resource Planning (ERP) as a Cloud Service delivers value by reducing initial and long term operating costs since infrastructure, platform and (certain) application management tasks are delegated to a specialist provider. Questions present at intersection of the ERP challenge landscape and the Cloud Computing opportunity horizon include characterization of Cloud friendly ERP modules and adaptation of stateful (on-premises ERP) components to a stateless platform. Contri...

Dendrimer ligands-capped CH3NH3PbBr3 perovskite nanocrystals with delayed halide exchange and record stability against both moisture and water

Science.gov (United States)

Xu, Yiren; Xu, Shuhong; Shao, Haibao; Jiang, Han; Cui, Yiping; Wang, Chunlei

2018-06-01

CH3NH3PbBr3 perovskite nanocrystals (NCs) suffer from poor stability because of their high sensitivity to environmental moisture and water. To solve this problem, previous works mainly focus on embedding perovskite NCs into water-resistant matrix to form large composites (size of microns or larger). As an alternative solution without serious changing of NC size, enhancing the stability of perovskite NCs themselves by ligand engineering is rarely reported. In this work, we used hyperbranched polyamidoamine (PAMAM) dendrimers with two different generations (G0 and G4) to synthesize CH3NH3PbBr3 perovskite NCs with high photoluminescence (PL) quantum yields (QY) above 70% and a new record stability. A novel dendrimers generation-dependent stability of perovskite NCs was observed. The water-resistance time is 18 h (27 h) for perovskite NCs capped by G0 (G4) generation of PAMAM, which is 7 times (11 times) longer than that of traditional oleic acid-capped NCs. Similar PAMAM generation-related stability is also observed in moisture-resistance tests. The stability time against moisture is 500 h (800 h) for G0 (G4) generation of PAMAM-capped perovskite NCs, which is a new record stability time against moisture for CH3NH3PbBr3 perovskite NCs. In addition, our results also indicate that PAMAM ligands outside perovskite NCs can dramatically slow down the speed of halide exchange. Even for the mixture of perovskite NCs with two different halide composition, the original luminescence properties of PAMAM-capped perovskite NCs can retain after mixing. In view of slow halide exchange speed, excellent water and moisture stability, PAMAM dendrimers-capped perovskite NCs and their mixture are available as color conversion single layer in fabrication of light-emitting diodes (LED).

Dendrimer ligands-capped CH3NH3PbBr3 perovskite nanocrystals with delayed halide exchange and record stability against both moisture and water.

Science.gov (United States)

Xu, Yiren; Xu, Shuhong; Shao, Haibao; Jiang, Han; Cui, Yiping; Wang, Chunlei

2018-06-08

CH 3 NH 3 PbBr 3 perovskite nanocrystals (NCs) suffer from poor stability because of their high sensitivity to environmental moisture and water. To solve this problem, previous works mainly focus on embedding perovskite NCs into water-resistant matrix to form large composites (size of microns or larger). As an alternative solution without serious changing of NC size, enhancing the stability of perovskite NCs themselves by ligand engineering is rarely reported. In this work, we used hyperbranched polyamidoamine (PAMAM) dendrimers with two different generations (G0 and G4) to synthesize CH 3 NH 3 PbBr 3 perovskite NCs with high photoluminescence (PL) quantum yields (QY) above 70% and a new record stability. A novel dendrimers generation-dependent stability of perovskite NCs was observed. The water-resistance time is 18 h (27 h) for perovskite NCs capped by G0 (G4) generation of PAMAM, which is 7 times (11 times) longer than that of traditional oleic acid-capped NCs. Similar PAMAM generation-related stability is also observed in moisture-resistance tests. The stability time against moisture is 500 h (800 h) for G0 (G4) generation of PAMAM-capped perovskite NCs, which is a new record stability time against moisture for CH 3 NH 3 PbBr 3 perovskite NCs. In addition, our results also indicate that PAMAM ligands outside perovskite NCs can dramatically slow down the speed of halide exchange. Even for the mixture of perovskite NCs with two different halide composition, the original luminescence properties of PAMAM-capped perovskite NCs can retain after mixing. In view of slow halide exchange speed, excellent water and moisture stability, PAMAM dendrimers-capped perovskite NCs and their mixture are available as color conversion single layer in fabrication of light-emitting diodes (LED).

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

The physico-chemical characterization was done by UV–visible, FTIR, scanning electron microscopy (SEM), transmission electron microscopy (TEM), EDX, TGA ... The RS-AgNPs and CSHD-AgNCs were assessedfor their anticancer activity against HeLa cell line by MTT method, and it reveals a dose–response activity, time ...

Neutron Compton scattering from selectively deuterated acetanilide

Science.gov (United States)

Wanderlingh, U. N.; Fielding, A. L.; Middendorf, H. D.

With the aim of developing the application of neutron Compton scattering (NCS) to molecular systems of biophysical interest, we are using the Compton spectrometer EVS at ISIS to characterize the momentum distribution of protons in peptide groups. In this contribution we present NCS measurements of the recoil peak (Compton profile) due to the amide proton in otherwise fully deuterated acetanilide (ACN), a widely studied model system for H-bonding and energy transfer in biomolecules. We obtain values for the average width of the potential well of the amide proton and its mean kinetic energy. Deviations from the Gaussian form of the Compton profile, analyzed on the basis of an expansion due to Sears, provide data relating to the Laplacian of the proton potential.

Composition, Taste, Aroma, and Antioxidant Activity of Solidified Noncentrifugal Brown Sugars Prepared from Whole Stalk and Separated Pith of Sugarcane (Saccharum officinarum L.).

Science.gov (United States)

Takahashi, Makoto; Ishmael, Mutanda; Asikin, Yonathan; Hirose, Naoto; Mizu, Masami; Shikanai, Takesi; Tamaki, Hajime; Wada, Koji

2016-10-25

In this study, 2 types of solidified noncentrifugal brown sugars (W-NCS and P-NCS) were prepared from the whole stalk and separated pith, respectively, of raw sugarcane (Saccharum officinarum L.). These products were discriminated in terms of their quality attributes, including color, sugars and minerals composition, taste, aroma, and antioxidant activity. The brown color of P-NCS was clearly different compared with that of W-NCS with a color difference value (ΔE * ) of 9.36. There was no difference in the sugars and minerals composition between the 2 types of sugar, which led to very similar taste profiles. However, P-NCS had a weaker aroma intensity than W-NCS did. Moreover, P-NCS retained more than 60% of the antioxidant activity of W-NCS. The information gleaned from this study might be used to select appropriate end-uses for these 2 types of sugars. © 2016 Institute of Food Technologists®.

Getting Across the Plasma Membrane and Beyond: Intracellular Uses of Colloidal Semiconductor Nanocrystals

Directory of Open Access Journals (Sweden)

Camilla Luccardini

2007-01-01

Full Text Available Semiconductor nanocrystals (NCs are increasingly being used as photoluminescen markers in biological imaging. Their brightness, large Stokes shift, and high photostability compared to organic fluorophores permit the exploration of biological phenomena at the single-molecule scale with superior temporal resolution and spatial precision. NCs have predominantly been used as extracellular markers for tagging and tracking membrane proteins. Successful internalization and intracellular labelling with NCs have been demonstrated for both fixed immunolabelled and live cells. However, the precise localization and subcellular compartment labelled are less clear. Generally, live cell studies are limited by the requirement of fairly invasive protocols for loading NCs and the relatively large size of NCs compared to the cellular machinery, along with the subsequent sequestration of NCs in endosomal/lysosomal compartments. For long-period observation the potential cytotoxicity of cytoplasmically loaded NCs must be evaluated. This review focuses on the challenges of intracellular uses of NCs.

Measuring the performance of maintenance service outsourcing.

Science.gov (United States)

Cruz, Antonio Miguel; Rincon, Adriana Maria Rios; Haugan, Gregory L

2013-01-01

The aims of this paper are (1) to identify the characteristics of maintenance service providers that directly impact maintenance service quality, using 18 independent covariables; (2) to quantify the change in risk these covariables present to service quality, measured in terms of equipment turnaround time (TAT). A survey was applied to every maintenance service provider (n = 19) for characterization purposes. The equipment inventory was characterized, and the TAT variable recorded and monitored for every work order of each service provider (N = 1,025). Finally, the research team conducted a statistical analysis to accomplish the research objectives. The results of this study offer strong empirical evidence that the most influential variables affecting the quality of maintenance service performance are the following: type of maintenance, availability of spare parts in the country, user training, technological complexity of the equipment, distance between the company and the hospital, and the number of maintenance visits performed by the company. The strength of the results obtained by the Cox model built are supported by the measure of the Rp,e(2) = 0.57 with a value of Rp,e= 0.75. Thus, the model explained 57% of the variation in equipment TAT, with moderate high positive correlation between the dependent variable (TAT) and independent variables.

Abnormal metabolic brain network associated with Parkinson's disease: replication on a new European sample

International Nuclear Information System (INIS)

Tomse, Petra; Jensterle, Luka; Grmek, Marko; Zaletel, Katja; Pirtosek, Zvezdan; Trost, Maja; Dhawan, Vijay; Peng, Shichun; Eidelberg, David; Ma, Yilong

2017-01-01

The purpose of this study was to identify the specific metabolic brain pattern characteristic for Parkinson's disease (PD): Parkinson's disease-related pattern (PDRP), using network analysis of [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) brain images in a cohort of Slovenian PD patients. Twenty PD patients (age 70.1 ± 7.8 years, Movement Disorder Society Unified Parkinson's Disease Motor Rating Scale (MDS-UPDRS-III) 38.3 ± 12.2; disease duration 4.3 ± 4.1 years) and 20 age-matched normal controls (NCs) underwent FDG-PET brain imaging. An automatic voxel-based scaled subprofile model/principal component analysis (SSM/PCA) was applied to these scans for PDRP-Slovenia identification. The pattern was characterized by relative hypermetabolism in pallidum, putamen, thalamus, brain stem, and cerebellum associated with hypometabolism in sensorimotor cortex, posterior parietal, occipital, and frontal cortices. The expression of PDRP-Slovenia discriminated PD patients from NCs (p < 0.0001) and correlated positively with patients' clinical score (MDS-UPDRS-III, p = 0.03). Additionally, its topography agrees well with the original PDRP (p < 0.001) identified in American cohort of PD patients. We validated the PDRP-Slovenia expression on additional FDG-PET scans of 20 PD patients, 20 NCs, and 25 patients with atypical parkinsonism (AP). We confirmed that the expression of PDRP-Slovenia manifests good diagnostic accuracy with specificity and sensitivity of 85-90% at optimal pattern expression cutoff for discrimination of PD patients and NCs and is not expressed in AP. PDRP-Slovenia proves to be a robust and reproducible functional imaging biomarker independent of patient population. It accurately differentiates PD patients from NCs and AP and correlates well with the clinical measure of PD progression. (orig.)

Abnormal metabolic brain network associated with Parkinson's disease: replication on a new European sample

Energy Technology Data Exchange (ETDEWEB)

Tomse, Petra; Jensterle, Luka; Grmek, Marko; Zaletel, Katja [University Medical Centre Ljubljana, Department of Nuclear Medicine, Ljubljana (Slovenia); Pirtosek, Zvezdan; Trost, Maja [University Medical Centre Ljubljana, Department of Neurology, 1000 Ljubljana (Slovenia); Dhawan, Vijay; Peng, Shichun; Eidelberg, David; Ma, Yilong [The Feinstein Institute for Medical Research, Center for Neurosciences, Manhasset, NY (United States)

2017-05-15

The purpose of this study was to identify the specific metabolic brain pattern characteristic for Parkinson's disease (PD): Parkinson's disease-related pattern (PDRP), using network analysis of [18F]-fluorodeoxyglucose positron emission tomography (FDG-PET) brain images in a cohort of Slovenian PD patients. Twenty PD patients (age 70.1 ± 7.8 years, Movement Disorder Society Unified Parkinson's Disease Motor Rating Scale (MDS-UPDRS-III) 38.3 ± 12.2; disease duration 4.3 ± 4.1 years) and 20 age-matched normal controls (NCs) underwent FDG-PET brain imaging. An automatic voxel-based scaled subprofile model/principal component analysis (SSM/PCA) was applied to these scans for PDRP-Slovenia identification. The pattern was characterized by relative hypermetabolism in pallidum, putamen, thalamus, brain stem, and cerebellum associated with hypometabolism in sensorimotor cortex, posterior parietal, occipital, and frontal cortices. The expression of PDRP-Slovenia discriminated PD patients from NCs (p < 0.0001) and correlated positively with patients' clinical score (MDS-UPDRS-III, p = 0.03). Additionally, its topography agrees well with the original PDRP (p < 0.001) identified in American cohort of PD patients. We validated the PDRP-Slovenia expression on additional FDG-PET scans of 20 PD patients, 20 NCs, and 25 patients with atypical parkinsonism (AP). We confirmed that the expression of PDRP-Slovenia manifests good diagnostic accuracy with specificity and sensitivity of 85-90% at optimal pattern expression cutoff for discrimination of PD patients and NCs and is not expressed in AP. PDRP-Slovenia proves to be a robust and reproducible functional imaging biomarker independent of patient population. It accurately differentiates PD patients from NCs and AP and correlates well with the clinical measure of PD progression. (orig.)

Facile synthesis of palladium nanoparticle doped polyaniline nanowires in soft templates for catalytic applications

Science.gov (United States)

Kshirasagar, Krushna J.; Markad, Uddhav S.; Saha, Abhijit; Sharma, Kiran Kumar K.; Sharma, Geeta K.

2017-02-01

Palladium nanoparticles doped polyaniline (Pd-PANI) nanocomposite (NCs) is synthesized in surfactant based liquid crystalline mesophase by chemical oxidation followed by radiolysis. The confinement of the liquid crystalline mesophase facilitates polymerization of aniline monomers and their 1D growth into polyaniline (PANI) nanowires by using ammonium persulfate. The PANI nanowires have an average diameter of 30-40 nm. The in situ radiolytic reduction of palladium ions ensures uniform size distribution of the palladium (Pd) nanoparticles on the surface of the PANI nanowires. The synthesized Pd-PANI nanocomposites show wire like structures of PANI (diameter ~30-40 nm) on which Pd nanoparticles of the size 10 nm are decorated. The identical average diameter of the PANI nanowires before and post gamma irradiation suggest high stability of the PANI nanowires in liquid crystalline mesophase. Surface characterization of the NCs were carried out using BET and XPS. The catalytic activity of Pd-PANI NCs are investigated in the reduction of methylene blue (MB) and 4-nitro phenol (4-NP) by sodium borohydride (NaBH4). The kinetics of the Pd-PANI NCs catalysed reactions are analysed using the Langmuir-Hinshelwood model. The apparent rate constant (k app) for the MB and 4-NP reduction reactions is 29  ×  10-3 s-1 and 20  ×  10-3 s-1 respectively with an actual Pd catalyst loading of 2.665  ×  10-4 ppm. Further, the recyclability of the Pd-PANI NCs catalyst in both the reduction reactions shows the stability of the catalyst up to four reaction cycles tested in this investigation and the multifunctional nature of the catalyst. The study provides a new approach for the directional synthesis of conducting polymer-metal nanocomposites and their possible application as a nanocatalyst in environmental remediation.

One-pot noninjection synthesis of Cu-doped Zn(x)Cd(1-x)S nanocrystals with emission color tunable over entire visible spectrum.

Science.gov (United States)

Zhang, Wenjin; Zhou, Xinggui; Zhong, Xinhua

2012-03-19

Unlike Mn doped quantum dots (d-dots), the emission color of Cu dopant in Cu d-dots is dependent on the nature, size, and composition of host nanocrystals (NCs). The tunable Cu dopant emission has been achieved via tuning the particle size of host NCs in previous reports. In this paper, for the first time we doped Cu impurity in Zn(x)Cd(1-x)S alloyed NCs and tuned the dopant emission in the whole visible spectrum via variation of the stoichiometric ratio of Zn/Cd precursors in the host Zn(x)Cd(1-x)S alloyed NCs. A facile noninjection and low cost approach for the synthesis of Cu:Zn(x)Cd(1-x)S d-dots was reported. The optical properties and structure of the obtained Cu:Zn(x)Cd(1-x)S d-dots have been characterized by UV-vis spectroscopy, photoluminescence (PL) spectroscopy, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The influences of various experimental variables, including Zn/Cd ratio, reaction temperature, and Cu dopant concentration, on the optical properties of Cu dopant emission have been systematically investigated. The as-prepared Cu:Zn(x)Cd(1-x)S d-dots did show PL emission but with quite low quantum yield (QY) (typically below 6%). With the deposition of ZnS shell around the Cu:Zn(x)Cd(1-x)S core NCs, the PL QY increased substantially with a maximum value of 65%. More importantly, the high PL QY can be preserved when the initial oil-soluble d-dots were transferred into aqueous media via ligand replacement by mercaptoundeconic acid. In addition, these d-dots have thermal stability up to 250 °C. © 2012 American Chemical Society

Luminescent Metal Nanoclusters for Potential Chemosensor Applications

Directory of Open Access Journals (Sweden)

Muthaiah Shellaiah

2017-12-01

Full Text Available Studies of metal nanocluster (M-NCs-based sensors for specific analyte detection have achieved significant progress in recent decades. Ultra-small-size (<2 nm M-NCs consist of several to a few hundred metal atoms and exhibit extraordinary physical and chemical properties. Similar to organic molecules, M-NCs display absorption and emission properties via electronic transitions between energy levels upon interaction with light. As such, researchers tend to apply M-NCs in diverse fields, such as in chemosensors, biological imaging, catalysis, and environmental and electronic devices. Chemo- and bio-sensory uses have been extensively explored with luminescent NCs of Au, Ag, Cu, and Pt as potential sensory materials. Luminescent bi-metallic NCs, such as Au-Ag, Au-Cu, Au-Pd, and Au-Pt have also been used as probes in chemosensory investigations. Both metallic and bi-metallic NCs have been utilized to detect various analytes, such as metal ions, anions, biomolecules, proteins, acidity or alkalinity of a solution (pH, and nucleic acids, at diverse detection ranges and limits. In this review, we have summarized the chemosensory applications of luminescent M-NCs and bi-metallic NCs.

Novel synthesis and characterization of Ag@TiO2 core shell nanostructure for non-enzymatic glucose sensor

Science.gov (United States)

T, Dayakar; Venkateswara Rao, K.; Vinodkumar, M.; Bikshalu, K.; Chakradhar, B.; Ramachandra Rao, K.

2018-03-01

Ag@TiO2 core-shell nano composite (ATCSNC) were synthesized by using Ocimum tenuiflorum leaves extract through a simple one-step hydrothermal route for Non-enzymatic glucose sensing material. The prepared NCs were characterized and found high crystallinity, red shift absorbance, interface-bonding parameters, rough surface and network like microstructure through XRD, Uv-vis, FTIR, SEM, and TEM. The prepared ATCSNC have been used for fabrication of glassy carbon electrode (GCE) and the same was applied to test its electro catalytic activity of glucose in 0.1 M NaOH. The promising results were recorded for ATCSNC/GCE with a high sensitivity (1968.72 μAm M-1cm-2), wide linear range (1 μM-8.1 mM), good response time (3 s), and excellent low detection limit (0.19 μM, S/N = 3). Furthermore, the designed sensor exhibits admirable stability and reproducibility, as well as attractive achievability for real sample analysis. As such, the proposed ATCSNC could be highly beneficial in the development of sustainable and eco-friendly glucose sensing devices.

Growth, cane yield and sugar content of six genotypes of sugarcane ...

African Journals Online (AJOL)

The growth and yield of six sugarcane genotypes were studied in field plots between 1999 and 2001, at Umudike, in the humid forest zone of southeastern Nigeria. Treatments comprised five improved sugarcane genotypes (NCS 001, NCS 003, NCS 004, NCS 005 and C062175) and one local variety (Umudike Local) ...

The BCube Crawler: Web Scale Data and Service Discovery for EarthCube.

Science.gov (United States)

Lopez, L. A.; Khalsa, S. J. S.; Duerr, R.; Tayachow, A.; Mingo, E.

2014-12-01

Web-crawling, a core component of the NSF-funded BCube project, is researching and applying the use of big data technologies to find and characterize different types of web services, catalog interfaces, and data feeds such as the ESIP OpenSearch, OGC W*S, THREDDS, and OAI-PMH that describe or provide access to scientific datasets. Given the scale of the Internet, which challenges even large search providers such as Google, the BCube plan for discovering these web accessible services is to subdivide the problem into three smaller, more tractable issues. The first, to be able to discover likely sites where relevant data and data services might be found, the second, to be able to deeply crawl the sites discovered to find any data and services which might be present. Lastly, to leverage the use of semantic technologies to characterize the services and data found, and to filter out everything but those relevant to the geosciences. To address the first two challenges BCube uses an adapted version of Apache Nutch (which originated Hadoop), a web scale crawler, and Amazon's ElasticMapReduce service for flexibility and cost effectiveness. For characterization of the services found, BCube is examining existing web service ontologies for their applicability to our needs and will re-use and/or extend these in order to query for services with specific well-defined characteristics in scientific datasets such as the use of geospatial namespaces. The original proposal for the crawler won a grant from Amazon's academic program, which allowed us to become operational; we successfully tested the Bcube Crawler at web scale obtaining a significant corpus, sizeable enough to enable work on characterization of the services and data found. There is still plenty of work to be done, doing "smart crawls" by managing the frontier, developing and enhancing our scoring algorithms and fully implementing the semantic characterization technologies. We describe the current status of the project

High luminescent fibers with hybrid SiO2-coated CdTe nanocrystals fabricated by electrospinning technique

International Nuclear Information System (INIS)

Cao, Yongqiang; Liu, Ning; Yang, Ping; Shi, Ruixia; Ma, Qian; Zhang, Aiyu; Zhu, Yuanna; Wang, Junpeng; Wang, Jianrong

2015-01-01

The polyvinylpyrrolidone (PVP) hybrid luminescent micro-/nanofibers doped with the novel hybrid SiO 2 -coated CdTe nanocrystals (HS-CdTe NCs) have been fabricated for the first time via the electrospinning technique. The morphologies and photoluminescence (PL) emissions of HS-CdTe/PVP micro-/nanofibers prepared by doping the HS-CdTe NCs with the different PL peak wavelength (571, 616, and 643 nm) in PVP fibers were investigated by optical and PL microscope. The results revealed that all the HS-CdTe/PVP hybrid fibers showed an ultralong length for several hundreds of micrometers and a relatively uniform diameter of 1000 ∼ 1200 nm. The hybrid fibers displayed a wavelength-tunable PL emission, determining by the PL of doped HS-CdTe NCs. Moreover, similar to the original PL properties of HS-CdTe NCs before the electrospinning, the HS-CdTe/PVP fibers also showed a series of superior PL properties, such as narrow and symmetry PL spectrum, high, and uniform brightness. For comparison purpose, we also prepared three CdTe/PVP hybrid fibers by doping the 553 nm, 600 nm, and 633 nm PL-emitting CdTe NCs respectively in PVP electrospinning fibers. The characterization results showed that, the obtained three CdTe/PVP hybrid fibers had a basically satisfactory micro-/nanofiber morphology with a long length and relatively uniform diameter, but all the fibers exhibited very weak PL emissions. The enormous contrast in PL properties between HS-CdTe/PVP and CdTe/PVP fibers should mainly be ascribed to the different connection modes of ligands with the NCs and the passivation effect of inert hybrid silica shell on HS-CdTe. It is hopeful that the high luminescent HS-CdTe/PVP micro-/nanofibers with the tunable PL peak wavelength would be a good candidate in the optical sensor, light-emitting devices (LEDs), nanometer-scale waveguides, and the other related photonic materials. - Highlights: • The HS-CdTe/PVP electrospun hybrid fibers were fabricated for the first time. • The

Characterisation of the interaction of the C-terminus of the dopamine D2 receptor with neuronal calcium sensor-1.

Directory of Open Access Journals (Sweden)

Lu-Yun Lian

Full Text Available NCS-1 is a member of the neuronal calcium sensor (NCS family of EF-hand Ca(2+ binding proteins which has been implicated in several physiological functions including regulation of neurotransmitter release, membrane traffic, voltage gated Ca(2+ channels, neuronal development, synaptic plasticity, and learning. NCS-1 binds to the dopamine D2 receptor, potentially affecting its internalisation and controlling dopamine D2 receptor surface expression. The D2 receptor binds NCS-1 via a short 16-residue cytoplasmic C-terminal tail. We have used NMR and fluorescence spectroscopy to characterise the interactions between the NCS-1/Ca(2+ and D2 peptide. The data show that NCS-1 binds D2 peptide with a K(d of ∼14.3 µM and stoichiometry of peptide binding to NCS-1 of 2:1. NMR chemical shift mapping confirms that D2 peptide binds to the large, solvent-exposed hydrophobic groove, on one face of the NCS-1 molecule, with residues affected by the presence of the peptide spanning both the N and C-terminal portions of the protein. The NMR and mutagenesis data further show that movement of the C-terminal helix 11 of NCS-1 to fully expose the hydrophobic groove is important for D2 peptide binding. Molecular docking using restraints derived from the NMR chemical shift data, together with the experimentally-derived stoichiometry, produced a model of the complex between NCS-1 and the dopamine receptor, in which two molecules of the receptor are able to simultaneously bind to the NCS-1 monomer.

Qbox-Services: Towards a Service-Oriented Quality Platform

Science.gov (United States)

González, Laura; Peralta, Verónika; Bouzeghoub, Mokrane; Ruggia, Raúl

The data quality market is characterized by a sparse offer of tools, providing individual functionalities which have their own interest with respect to quality assessment. But interoperating among these tools remains a technical challenge because of the heterogeneity of their models and access patterns. On the other side, quality analysts require more and more integration facilities that allow them to consolidate and aggregate multiple quality measures acquired from different observations. The QBox platform, developed within the ANR Quadris project, aims at filling this gap by supplying a service-based integration infrastructure that allows interoperability among several quality tools and provides an OLAP-based quality model to support multidimensional analysis. This paper focuses on the architectural principles of this infrastructure and illustrates its use through specific examples of quality services.

{331}-Faceted trisoctahedral gold nanocrystals: synthesis, superior electrocatalytic performance and highly efficient SERS activity

Science.gov (United States)

Song, Yahui; Miao, Tingting; Zhang, Peina; Bi, Cuixia; Xia, Haibing; Wang, Dayang; Tao, Xutang

2015-04-01

We investigate the effect of gold (Au) seeds prepared in cetyltrimethylammonium chloride solution (CTAC-Au seeds) on the index facets of trisoctahedral gold nanocrystals (TOH Au NCs). We demonstrate that monodisperse {331}-faceted TOH Au NCs with controllable sizes (from 60 to 255 nm) can be successfully prepared in high yield by using 3.0 nm CTAC-Au seeds or as-prepared 70 nm TOH Au NCs as seeds. We find that the electrocatalytic performance on methanol oxidation and surface enhancement Raman spectroscopy (SERS) activity of {331}-faceted TOH Au NCs is size-dependent. In comparison with well-known nanoporous gold (0.088 mA cm-2), {331}-faceted TOH Au NCs with sizes of 110 nm exhibit fairly high catalytic activity (0.178 mA cm-2) on methanol oxidation (1.0 M) in alkaline media due to the presence of increasing density of atomic steps, ledges, and kinks on the NC surfaces. Their current density is reduced by less than 7% after 500 cycling tests. {331}-Faceted TOH Au NCs with sizes of 175 nm exhibit the highest SERS activity for 4-aminothiophenol (4-ATP) molecules. The enhancement factors of a1 modes of 4-ATP molecules can reach the order of 109 when the 4-ATP concentration is 3 × 10-6 M. Moreover, Raman signals (ag modes) of 4,4'-dimercaptoazobenzene (DMAB) molecules on TOH Au NCs are stronger than those on spherical Au NCs of comparable size due to the enhanced laser-induced transformation of 4-ATP molecules by high-index {331}-facets during SERS measurement. Furthermore, the SERS intensities of 4-methylbenzenethiol (4-MTP) molecules on TOH Au NCs are also higher than those on spherical Au NCs of comparable size due to sharp extremities.We investigate the effect of gold (Au) seeds prepared in cetyltrimethylammonium chloride solution (CTAC-Au seeds) on the index facets of trisoctahedral gold nanocrystals (TOH Au NCs). We demonstrate that monodisperse {331}-faceted TOH Au NCs with controllable sizes (from 60 to 255 nm) can be successfully prepared in high yield by

Numb chin syndrome as a primary presentation of metastatic breast cancer

Directory of Open Access Journals (Sweden)

Jasjot Sahni

2017-01-01

Full Text Available Numb chin syndrome (NCS is characterized by facial neuropathy along the distribution of the mental branch of the trigeminal nerve. We report a case of NCS in a 65 year old woman who initially presented to her dentist with nonspecific symptoms that she thought were related to a tooth infection. The patient was otherwise healthy and her medical history was significant for breast cancer treated 20 years prior; her cancer was thought to be in complete remission. Upon clinical examination and conventional dental radiography, no pathology was seen such as odontogenic, periodontal, or jawbone infection. Only paresthesia and hypoesthesia was noted unilaterally in her left chin, jaw and lower lip. A computed tomography scan was obtained for further evaluation and revealed lytic metastatic disease involving the right mandible at the level of the mandibular foramen; lytic lesions of the thoracic vertebrae and multiple pulmonary nodules were also noted. Oncologic referral was made immediately which confirmed a diagnosis of metastatic breast cancer. Familiarity with NCS is important for oral health care providers in order to identify etiology and differential diagnosis, as well as to provide appropriate referral and management.

Size Dependence of Doping by a Vacancy Formation Reaction in Copper Sulfide Nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Elimelech, Orian [The Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904 Israel; Liu, Jing [Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook NY 11794 USA; Plonka, Anna M. [Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook NY 11794 USA; Frenkel, Anatoly I. [Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook NY 11794 USA; Banin, Uri [The Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 91904 Israel

2017-07-19

Doping of nanocrystals (NCs) is a key, yet underexplored, approach for tuning of the electronic properties of semiconductors. An important route for doping of NCs is by vacancy formation. The size and concentration dependence of doping was studied in copper(I) sulfide (Cu2S) NCs through a redox reaction with iodine molecules (I2), which formed vacancies accompanied by a localized surface plasmon response. X-ray spectroscopy and diffraction reveal transformation from Cu2S to Cu-depleted phases, along with CuI formation. Greater reaction efficiency was observed for larger NCs. This behavior is attributed to interplay of the vacancy formation energy, which decreases for smaller sized NCs, and the growth of CuI on the NC surface, which is favored on well-defined facets of larger NCs. This doping process allows tuning of the plasmonic properties of a semiconductor across a wide range of plasmonic frequencies by varying the size of NCs and the concentration of iodine. Controlled vacancy doping of NCs may be used to tune and tailor semiconductors for use in optoelectronic applications.

Steam generator tube fitness-for-service guidelines

International Nuclear Information System (INIS)

Gorman, J.A.; Harris, J.E.; Lowenstein, D.B.

1995-07-01

The objectives of this project were to characterize defect mechanisms which could affect the integrity of steam generator tubes, to review and critique state-of-the-art Canadian and international steam generator tube fitness-for-service criteria and guidelines, and to obtain recommendations for criteria that could be used to assess fitness-for service guidelines for steam generator tubes containing defects in Canadian power plant service. Degradation mechanisms, that could affect CANDU steam generator tubes in Canada, have been characterized. The design standards and safety criteria that apply to steam generator tubing in nuclear power plant service in Canada and in Belgium, France, Japan, Spain, Sweden, and the USA have been reviewed and described. The fitness-for-service guidelines used for a variety of specific defect types in Canada and internationally have been evaluated and described in detail in order to highlight the considerations involved in developing such defect specific guidelines. Existing procedures for defect assessment and disposition have been identified, including inspection and examination practices. The approaches used in Canada and in Belgium, France, Japan, Spain, Sweden, and the USA for fitness-for-service guidelines were compared and contrasted for a variety of defect mechanisms. The strengths and weaknesses of the various approaches have been assessed. The report presents recommendations on approaches that may be adopted in the development of fitness-for-service guidelines for use in the dispositioning of steam generator tubing defects in Canada. (author). 175 refs., 2 tabs., 28 figs

Nondestructive testing for microstructural characterization in 9Cr-1Mo ferritic steel towards assessment of fabrication quality and in-service degradation

Energy Technology Data Exchange (ETDEWEB)

Jayakumar, T.; Rao, K.B.S.; Raj, Baldev [Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

1999-07-01

The paper discusses the usefulness of non destructive testing for microstructural characterization in 9Cr-1Mo ferritic steel. Ultrasonic velocity and attenuation measurements and spectral analysis have been used in a complementary way for characterizing Ac{sub 1} and Ac{sub 3} temperatures, amount of martensite and ferrite, dissolution of V{sub 4}C{sub 3} and NbC and formation of {delta}-ferrite. The microstructural degradation occurring due to thermal ageing and creep has also been studied by ultrasonic velocity measurements. Magnetic Barkhausen noise technique has been used for estimating the extent of various regions in heat affected zone (HAZ) of 9Cr-1Mo ferritic steel weldment. The same technique has been used for the assessment of low cycle fatigue damage in 9Cr-1Mo steel. The study establishes that non destructive methods can be used for the assessment of fabrication quality and in service degradation of the components. (author)

Self-assembled nanocomplexes of anionic pullulan and polyallylamine for DNA and pH-sensitive intracellular drug delivery

International Nuclear Information System (INIS)

Vora, Lalit; Tyagi, Monica; Patel, Ketan; Gupta, Sanjay; Vavia, Pradeep

2014-01-01

The amalgamation of chemotherapy and gene therapy is promising treatment option for cancer. In this study, novel biocompatible self-assembled nanocomplexes (NCs) between carboxylmethylated pullulan t335 (CMP) with polyallylamine (CMP–PAA NCs) were developed for plasmid DNA (pDNA) and pH-sensitive doxorubicin (DOX) delivery. DOX was conjugated to CMP (DOX–CMP) via hydrazone and confirmed by FTIR and 1 H-NMR. In vitro release studies of pH-sensitive DOX–CMP conjugate showed 23 and 85 % release after 48 h at pH 7.4 (physiological pH) and pH 5 (intracellular/tumoral pH), respectively. The CMP–PAA NCs or DOX–CMP–PAA NCs self-assembled into a nanosized (<250 nm) spherical shape as confirmed by DLS and TEM. The hemolysis and cytotoxicity study indicated that the CMP–PAA NCs did not show cytotoxicity in comparison with plain polyallylamine. Gel retardation assay showed complete binding of pDNA with CMP–PAA NCs at 1:2 weight ratio. CMP–PAA NCs/pDNA showed significantly higher transfection in HEK293 cells compared to PAA/pDNA complexes. Confocal imaging demonstrated successful cellular uptake of DOX–CMP–PAA NCs in HEK293 cells. Thus, NCs hold great potential for targeted pDNA and pH-sensitive intratumoral drug delivery

Insight on specificity of uracil permeases of the NAT/NCS2 family from analysis of the transporter encoded in the pyrimidine utilization operon of Escherichia coli.

Science.gov (United States)

Botou, Maria; Lazou, Panayiota; Papakostas, Konstantinos; Lambrinidis, George; Evangelidis, Thomas; Mikros, Emmanuel; Frillingos, Stathis

2018-04-01

The uracil permease UraA of Escherichia coli is a structurally known prototype for the ubiquitous Nucleobase-Ascorbate Transporter (NAT) or Nucleobase-Cation Symporter-2 (NCS2) family and represents a well-defined subgroup of bacterial homologs that remain functionally unstudied. Here, we analyze four of these homologs, including RutG of E. coli which shares 35% identity with UraA and is encoded in the catabolic rut (pyrimidine utilization) operon. Using amplified expression in E. coli K-12, we show that RutG is a high-affinity permease for uracil, thymine and, at low efficiency, xanthine and recognizes also 5-fluorouracil and oxypurinol. In contrast, UraA and the homologs from Acinetobacter calcoaceticus and Aeromonas veronii are permeases specific for uracil and 5-fluorouracil. Molecular docking indicates that thymine is hindered from binding to UraA by a highly conserved Phe residue which is absent in RutG. Site-directed replacement of this Phe with Ala in the three uracil-specific homologs allows high-affinity recognition and/or transport of thymine, emulating the RutG profile. Furthermore, all RutG orthologs from enterobacteria retain an Ala at this position, implying that they can use both uracil and thymine and, possibly, xanthine as substrates and provide the bacterial cell with a range of catabolizable nucleobases. © 2018 John Wiley & Sons Ltd.

Trade in health services.

Science.gov (United States)

Chanda, Rupa

2002-01-01

In light of the increasing globalization of the health sector, this article examines ways in which health services can be traded, using the mode-wise characterization of trade defined in the General Agreement on Trade in Services. The trade modes include cross- border delivery of health services via physical and electronic means, and cross-border movement of consumers, professionals, and capital. An examination of the positive and negative implications of trade in health services for equity, efficiency, quality, and access to health care indicates that health services trade has brought mixed benefits and that there is a clear role for policy measures to mitigate the adverse consequences and facilitate the gains. Some policy measures and priority areas for action are outlined, including steps to address the "brain drain"; increasing investment in the health sector and prioritizing this investment better; and promoting linkages between private and public health care services to ensure equity. Data collection, measures, and studies on health services trade all need to be improved, to assess better the magnitude and potential implications of this trade. In this context, the potential costs and benefits of trade in health services are shaped by the underlying structural conditions and existing regulatory, policy, and infrastructure in the health sector. Thus, appropriate policies and safeguard measures are required to take advantage of globalization in health services. PMID:11953795

Gold Nanocluster-Mediated Cellular Death under Electromagnetic Radiation.

Science.gov (United States)

Cifuentes-Rius, Anna; Ivask, Angela; Das, Shreya; Penya-Auladell, Nuria; Fabregas, Laura; Fletcher, Nicholas L; Houston, Zachary H; Thurecht, Kristofer J; Voelcker, Nicolas H

2017-11-29

Gold nanoclusters (Au NCs) have become a promising nanomaterial for cancer therapy because of their biocompatibility and fluorescent properties. In this study, the effect of ultrasmall protein-stabilized 2 nm Au NCs on six types of mammalian cells (fibroblasts, B-lymphocytes, glioblastoma, neuroblastoma, and two types of prostate cancer cells) under electromagnetic radiation is investigated. Cellular association of Au NCs in vitro is concentration-dependent, and Au NCs have low intrinsic toxicity. However, when Au NC-incubated cells are exposed to a 1 GHz electromagnetic field (microwave radiation), cell viability significantly decreases, thus demonstrating that Au NCs exhibit specific microwave-dependent cytotoxicity, likely resulting from localized heating. Upon i.v. injection in mice, Au NCs are still present at 24 h post administration. Considering the specific microwave-dependent cytotoxicity and low intrinsic toxicity, our work suggests the potential of Au NCs as effective and safe nanomedicines for cancer therapy.

A novel local anesthetic system: transcriptional transactivator peptide-decorated nanocarriers for skin delivery of ropivacaine

Directory of Open Access Journals (Sweden)

Chen CY

2017-06-01

Full Text Available Chuanyu Chen, Peijun You Department of Anesthesiology, Shandong Jining No 1 People’s Hospital, Jining, Shandong, People’s Republic of China Purpose: Barrier properties of the skin and physicochemical properties of drugs are the main factors for the delivery of local anesthetic molecules. The present work evaluates the anesthetic efficacy of drug-loaded nanocarrier (NC systems for the delivery of local anesthetic drug, ropivacaine (RVC. Methods: In this study, transcriptional transactivator peptide (TAT-decorated RVC-loaded NCs (TAT-RVC/NCs were successfully fabricated. Physicochemical properties of NCs were determined in terms of particle size, zeta potential, drug encapsulation efficiency, drug-loading capacity, stability, and in vitro drug release. The skin permeation of NCs was examined using a Franz diffusion cell mounted with depilated mouse skin in vitro, and in vivo anesthetic effect was evaluated in mice. Results: The results showed that TAT-RVC/NCs have a mean diameter of 133.2 nm and high drug-loading capacity of 81.7%. From the in vitro skin permeation results, it was observed that transdermal flux of TAT-RVC/NCs was higher than that of RVC-loaded NCs (RVC/NCs and RVC injection. The evaluation of in vivo anesthetic effect illustrated that TAT-RVC/NCs can enhance the transdermal delivery of RVC by reducing the pain threshold in mice. Conclusion: These results indicate that TAT-decorated NCs systems are useful for overcoming the barrier function of the skin, decreasing the dosage of RVC and enhancing the anesthetic effect. Therefore, TAT-decorated NCs can be used as an effective transdermal delivery system for local anesthesia. Keywords: local anesthetic system, ropivacaine, transcriptional transactivator peptide, nanocarriers, skin delivery

Insight into the mechanism revealing the peroxidase mimetic catalytic activity of quaternary CuZnFeS nanocrystals: colorimetric biosensing of hydrogen peroxide and glucose

Science.gov (United States)

Dalui, Amit; Pradhan, Bapi; Thupakula, Umamahesh; Khan, Ali Hossain; Kumar, Gundam Sandeep; Ghosh, Tanmay; Satpati, Biswarup; Acharya, Somobrata

2015-05-01

Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been evaluated by catalytic oxidation of the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). CZIS NCs demonstrate the synergistic effect of elemental composition and photoactivity towards peroxidase-like activity. The quaternary CZIS NCs show enhanced intrinsic peroxidase-like activity compared to the binary NCs with the same constituent elements. Intrinsic peroxidase-like activity has been correlated with the energy band position of CZIS NCs extracted using scanning tunneling spectroscopy and ultraviolet photoelectron spectroscopy. Kinetic analyses indicate Michaelis-Menten enzyme kinetic model catalytic behavior describing the rate of the enzymatic reaction by correlating the reaction rate with substrate concentration. Typical color reactions arising from the catalytic oxidation of TMB over CZIS NCs with H2O2 have been utilized to establish a simple and sensitive colorimetric assay for detection of H2O2 and glucose. CZIS NCs are recyclable catalysts showing high efficiency in multiple uses. Our study may open up the possibility of designing new photoactive multi-component alloyed NCs as enzyme mimetics in biotechnology applications.Artificial enzyme mimetics have attracted immense interest recently because natural enzymes undergo easy denaturation under environmental conditions restricting practical usefulness. We report for the first time chalcopyrite CuZnFeS (CZIS) alloyed nanocrystals (NCs) as novel biomimetic catalysts with efficient intrinsic peroxidase-like activity. Novel peroxidase activities of CZIS NCs have been

Bidentate Ligand-passivated CsPbI3 Perovskite Nanocrystals for Stable Near-unity Photoluminescence Quantum Yield and Efficient Red Light-emitting Diodes

KAUST Repository

Pan, Jun

2017-12-17

Although halide perovskite nanocrystals (NCs) are promising materials for optoelectronic devices, they suffer severely from chemical and phase instabilities. Moreover, the common capping ligands like oleic acid and oleylamine that encapsulate the NCs will form an insulating layer, precluding their utility in optoelectronic devices. To overcome these limitations, we develop a post-synthesis passivation process for CsPbI3 NCs by using a bidentate ligand, namely 2,2’-Iminodibenzoic acid. Our passivated NCs exhibit narrow red photoluminescence with exceptional quantum yield (close to unity) and substantially improved stability. The passivated NCs enabled us to realize red light-emitting diodes (LEDs) with 5.02% external quantum efficiency and 748 cd/m2 luminance, surpassing by far LEDs made from the non-passivated NCs.

UV and air stability of high-efficiency photoluminescent silicon nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Yang, Jihua, E-mail: yangj@umn.edu [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Liptak, Richard [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Ave, Terre Haute, IN 47803 (United States); Rowe, David; Wu, Jeslin [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Casey, James; Witker, David [Dow Corning Corporation, 2200 W. Salzburg Road, Midland, MI 48686 (United States); Campbell, Stephen A. [Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455 (United States); Kortshagen, Uwe, E-mail: kortshagen@umn.edu [Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455 (United States)

2014-12-30

The effects of UV light and air exposure on the photoluminescent properties of nonthermal plasma-synthesized silicon nanocrystals (Si NCs) were investigated. Si NCs with high-efficiency photoluminescence (PL) have been achieved via a post-synthesis hydrosilylation process. Photobleaching is observed within the first few hours of ultra-violet (UV) irradiation. Equilibrium is reached after ∼4 h of UV exposure wherein the Si NCs are able to retain 52% of the initially measured PL quantum yield (PLQY). UV-treated Si NCs showed recovery of PL with time. Gas-phase passivation of Si NCs by hydrogen afterglow injection improves PLQY and PL stability against UV and air exposure. Additionally, phosphorous doping can also improve UV stability of photoluminescent Si NCs.

Bidentate Ligand-passivated CsPbI3 Perovskite Nanocrystals for Stable Near-unity Photoluminescence Quantum Yield and Efficient Red Light-emitting Diodes

KAUST Repository

Pan, Jun; Shang, Yuequn; Yin, Jun; de Bastiani, Michele; Peng, Wei; Dursun, Ibrahim; Sinatra, Lutfan; El-Zohry, Ahmed M.; Hedhili, Mohamed N.; Emwas, Abdul-Hamid M.; Mohammed, Omar F.; Ning, Zhijun; Bakr, Osman

2017-01-01

Although halide perovskite nanocrystals (NCs) are promising materials for optoelectronic devices, they suffer severely from chemical and phase instabilities. Moreover, the common capping ligands like oleic acid and oleylamine that encapsulate the NCs will form an insulating layer, precluding their utility in optoelectronic devices. To overcome these limitations, we develop a post-synthesis passivation process for CsPbI3 NCs by using a bidentate ligand, namely 2,2’-Iminodibenzoic acid. Our passivated NCs exhibit narrow red photoluminescence with exceptional quantum yield (close to unity) and substantially improved stability. The passivated NCs enabled us to realize red light-emitting diodes (LEDs) with 5.02% external quantum efficiency and 748 cd/m2 luminance, surpassing by far LEDs made from the non-passivated NCs.

The influence of lysosomal stability of silver nanomaterials on their toxicity to human cells.

Science.gov (United States)

Setyawati, Magdiel Inggrid; Yuan, Xun; Xie, Jianping; Leong, David Tai

2014-08-01

How silver nanomaterials (Ag NMs) could induce toxicity has been debated heatedly by many researchers. We utilized Ag nanoclusters (Ag NCs) with the same size and ligand protection but different core surface speciation. Ag(+)-rich NCs (Ag(+)-R NCs) and their counterpart, the reduced Ag(0)-rich NCs (Ag(0)-R NCs) are synthesized to represent possible dichotomous stages in silver nanomaterial degradation process. Here we show Ag(0)-R NCs induce higher cellular toxicity when compared to Ag(+)-R NCs. This cellular toxicity is brought about via the modulation of reactive oxygen species (ROS) in cells as a result of the more rapid release of Ag species from Ag(0)-R NCs and subsequent oxidation into Ag(+) in the lysosomal compartment. The weaker Ag(0)-R bond greatly potentiated the release of Ag species in the acidic and enzymatic processes within the lysosomes. Since lysosomes are absent in bacteria, increasing silver nanomaterials stability may lower toxicity in mammalian cells whilst not reducing their efficacy to fight bacteria; this redesign can result in a safer silver nanomaterial. Copyright © 2014 Elsevier Ltd. All rights reserved.

Shape-Controlled Synthesis of High-Quality Cu7 S4 Nanocrystals for Efficient Light-Induced Water Evaporation.

Science.gov (United States)

Zhang, Changbo; Yan, Cong; Xue, Zhenjie; Yu, Wei; Xie, Yinde; Wang, Tie

2016-10-01

Copper sulfides (Cu 2-x S), are a novel kind of photothermal material exhibiting significant photothermal conversion efficiency, making them very attractive in various energy conversion related devices. Preparing high quality uniform Cu 2-x S nanocrystals (NCs) is a top priority for further energy-and sustainability relevant nanodevices. Here, a shape-controlled high quality Cu 7 S 4 NCs synthesis strategy is reported using sulfur in 1-octadecene as precursor by varying the heating temperature, as well as its forming mechanism. The performance of the Cu 7 S 4 NCs is further explored for light-driven water evaporation without the need of heating the bulk liquid to the boiling point, and the results suggest that as-synthesized highly monodisperse NCs perform higher evaporation rate than polydisperse NCs under the identical morphology. Furthermore, disk-like NCs exhibit higher water evaporation rate than spherical NCs. The water evaporation rate can be further enhanced by assembling the organic phase Cu 7 S 4 NCs into a dense film on the aqueous solution surface. The maximum photothermal conversion efficiency is as high as 77.1%. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Polylactic Acid-Lemongrass Essential Oil Nanocapsules with Antimicrobial Properties.

Science.gov (United States)

Liakos, Ioannis L; Grumezescu, Alexandru Mihai; Holban, Alina Maria; Florin, Iordache; D'Autilia, Francesca; Carzino, Riccardo; Bianchini, Paolo; Athanassiou, Athanassia

2016-07-07

Polylactic acid was combined with lemongrass essential oil (EO) to produce functional nanocapsules (NCs). The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid-lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization.

Polylactic Acid—Lemongrass Essential Oil Nanocapsules with Antimicrobial Properties

Directory of Open Access Journals (Sweden)

Ioannis L. Liakos

2016-07-01

Full Text Available Polylactic acid was combined with lemongrass essential oil (EO to produce functional nanocapsules (NCs. The obtained polylactic acid nanoparticles showed antimicrobial activity both with and without the presence of lemongrass oil; however, the presence of EO improved the activity of the NCs. The presence of lemongrass assisted the formation of well-separated NCs and also provided enhanced antimicrobial properties, since lemongrass is known for its antimicrobial character. Fluorescence microscopy was used to optically observe the nanoparticles and NCs and revealed the attachment of lemongrass oil with the polylactic acid NCs. Dynamic light scattering was used to determine their size. UV absorption was used to determine the exact amount of lemongrass oil found in the polylactic acid—lemongrass oil NCs, which was important for understanding the minimum inhibitory concentration for the antimicrobial experiments. A series of clinically important microbial species were used in the study and the obtained NCs proved to have very good antimicrobial properties against all tested strains. Such NCs can be used for the design of ecological strategies, based on natural alternatives, which may be efficient against severe infections, including those that involve resistant pathogens and biofilms or those with difficult to reach localization.

Salts-based size-selective precipitation: toward mass precipitation of aqueous nanoparticles.

Science.gov (United States)

Wang, Chun-Lei; Fang, Min; Xu, Shu-Hong; Cui, Yi-Ping

2010-01-19

Purification is a necessary step before the application of nanocrystals (NCs), since the excess matter in nanoparticles solution usually causes a disadvantage to their subsequent coupling or assembling with other materials. In this work, a novel salts-based precipitation technique is originally developed for the precipitation and size-selective precipitation of aqueous NCs. Simply by addition of salts, NCs can be precipitated from the solution. After decantation of the supernatant solution, the precipitates can be dispersed in water again. By means of adjusting the addition amount of salt, size-selective precipitation of aqueous NCs can be achieved. Namely, the NCs with large size are precipitated preferentially, leaving small NCs in solution. Compared with the traditional nonsolvents-based precipitation technique, the current one is simpler and more rapid due to the avoidance of condensation and heating manipulations used in the traditional precipitation process. Moreover, the salts-based precipitation technique was generally available for the precipitation of aqueous nanoparticles, no matter if there were semiconductor NCs or metal nanoparticles. Simultaneously, the cost of the current method is also much lower than that of the traditional nonsolvents-based precipitation technique, making it applicable for mass purification of aqueous NCs.

Ensemble averaged structure–function relationship for nanocrystals: effective superparamagnetic Fe clusters with catalytically active Pt skin [Ensemble averaged structure-function relationship for composite nanocrystals: magnetic bcc Fe clusters with catalytically active fcc Pt skin

Energy Technology Data Exchange (ETDEWEB)

Petkov, Valeri [Central Michigan University, Mt. Pleasant, MI (United States); Prasai, Binay [Central Michigan University, Mt. Pleasant, MI (United States); Shastri, Sarvjit [Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division; Park, Hyun-Uk [Sungkyunkwan University, Suwon (Korea). Department of Chemistry; Kwon, Young-Uk [Sungkyunkwan University, Suwon (Korea). Department of Chemistry; Skumryev, Vassil [Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona (Spain); Universitat Autònoma de Barcelona (Spain). Department of Physics

2017-09-12

Practical applications require the production and usage of metallic nanocrystals (NCs) in large ensembles. Besides, due to their cluster-bulk solid duality, metallic NCs exhibit a large degree of structural diversity. This poses the question as to what atomic-scale basis is to be used when the structure–function relationship for metallic NCs is to be quantified precisely. In this paper, we address the question by studying bi-functional Fe core-Pt skin type NCs optimized for practical applications. In particular, the cluster-like Fe core and skin-like Pt surface of the NCs exhibit superparamagnetic properties and a superb catalytic activity for the oxygen reduction reaction, respectively. We determine the atomic-scale structure of the NCs by non-traditional resonant high-energy X-ray diffraction coupled to atomic pair distribution function analysis. Using the experimental structure data we explain the observed magnetic and catalytic behavior of the NCs in a quantitative manner. Lastly, we demonstrate that NC ensemble-averaged 3D positions of atoms obtained by advanced X-ray scattering techniques are a very proper basis for not only establishing but also quantifying the structure–function relationship for the increasingly complex metallic NCs explored for practical applications.

Interfacial synthesis of polyethyleneimine-protected copper nanoclusters: Size-dependent tunable photoluminescence, pH sensor and bioimaging.

Science.gov (United States)

Wang, Chan; Yao, Yagang; Song, Qijun

2016-04-01

The copper nanoclusters (CuNCs) offer excellent potential as functional biological probes due to their unique photoluminescence (PL) properties. Herein, CuNCs capped with hyperbranched polyethylenimine (PEI) were prepared by the interfacial etching approach. The resultant PEI-CuNCs exhibited good dispersion and strong fluorescence with high quantum yields (QYs, up to 7.5%), which would be endowed for bioimaging system. By changing the reaction temperatures from 25 to 150 °C, the size of PEI-CuNCs changed from 1.8 to 3.5 nm, and thus tunable PL were achieved, which was confirmed by transmission electron microscopy (TEM) imagings and PL spectra. Besides, PEI-CuNCs had smart absorption characteristics that the color changes from colorless to blue with changing the pH value from 2.0 to 13.2, and thus they could be used as color indicator for pH detection. In addition, the PEI-CuNCs exhibited good biocompatibility and low cytotoxicity to 293T cells through MTT assay. Owing to the positively charged of PEI-CuNCs surface, they had the ability to capture DNA, and the PEI-CuNCs/DNA complexes could get access to cells for efficient gene expression. Armed with these attractive properties, the synthesized PEI-CuNCs are quite promising in biological applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Facile Synthesis of N-Doped Graphene-Like Carbon Nanoflakes as Efficient and Stable Electrocatalysts for the Oxygen Reduction Reaction

Science.gov (United States)

Gu, Daguo; Zhou, Yao; Ma, Ruguang; Wang, Fangfang; Liu, Qian; Wang, Jiacheng

2018-06-01

A series of N-doped carbon materials (NCs) were synthesized by using biomass citric acid and dicyandiamide as renewable raw materials via a facile one-step pyrolysis method. The characterization of microstructural features shows that the NCs samples are composed of few-layered graphene-like nanoflakes with controlled in situ N doping, which is attributed to the confined pyrolysis of citric acid within the interlayers of the dicyandiamide-derived g-C3N4 with high nitrogen contents. Evidently, the pore volumes of the NCs increased with the increasing content of dicyandiamide in the precursor. Among these samples, the NCs nanoflakes prepared with the citric acid/dicyandiamide mass ratio of 1:6, NC-6, show the highest N content of 6.2 at%, in which pyridinic and graphitic N groups are predominant. Compared to the commercial Pt/C catalyst, the as-prepared NC-6 exhibits a small negative shift of 66 mV at the half-wave potential, demonstrating excellent electrocatalytic activity in the oxygen reduction reaction. Moreover, NC-6 also shows better long-term stability and resistance to methanol crossover compared to Pt/C. The efficient and stable performance are attributed to the graphene-like microstructure and high content of pyridinic and graphitic doped nitrogen in the sample, which creates more active sites as well as facilitating charge transfer due to the close four-electron reaction pathway. The superior electrocatalytic activity coupled with the facile synthetic method presents a new pathway to cost-effective electrocatalysts for practical fuel cells or metal-air batteries.

Morphological and luminescent evolution of near-infrared-emitting CdTe{sub x}Se{sub 1-x} nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Zhang Ruili; Yang Ping, E-mail: mse_yangp@ujn.edu.cn [University of Jinan, School of Material Science and Engineering (China)

2012-08-15

A facile organic route has been developed to synthesize CdTe{sub x}Se{sub 1-x} nanocrystals (NCs) using stearic acid as a capping agent. Because of growth kinetics of CdTe and CdSe, the molar ratio of Te/Se enables CdTe{sub x}Se{sub 1-x} NCs with various morphologies. By increasing the Te/Se ratio, the morphology of the NCs can be adjusted from tetrahedron to tetrapod. This is ascribed to the energy difference between wurtzite and the zinc-blende structures, which determines the nucleation and growth processes of the NCs. The diameters of the branches of tetrapod were 4-6 nm and their lengths were 7-20 nm. The CdTe{sub x}Se{sub 1-x} NCs revealed near-infrared (NIR) range (700-800 nm) photoluminescence (PL). The PL properties of the resulting NCs are strongly dependent on preparation conditions such as the molar ratio of Te/Se as well as the reaction temperature and time. In the cases of various reaction temperature (120-260 Degree-Sign C), the NCs revealed adjusted PL peak wavelength from visible to NIR range and narrow PL spectra. In addition, even though a high Te/Se molar ratio (0.67) was used, the CdTe{sub x}Se{sub 1-x} NCs revealed improved stability compared with CdTe NCs. Being coated with a composite Cd{sub y}Zn{sub 1-y}S shell, the PL intensity was drastically enhanced. The approach described here is utilizable to the fabrication of other semiconductor NCs with various morphologies. Because of the adjusted morphologies, tunable NIR range emission, and high stability of these composite NCs, we will focus on their applications such as solar cell and biolabeling.

Enhanced conductive loss in nickel–cobalt sulfide nanostructures for highly efficient microwave absorption and shielding

Science.gov (United States)

Li, Wanrong; Zhou, Min; Lu, Fei; Liu, Hongfei; Zhou, Yuxue; Zhu, Jun; Zeng, Xianghua

2018-06-01

Microwave-absorbing materials with light weight and high efficiency are desirable in addressing electromagnetic interference (EMI) problems. Herein, a nickel–cobalt sulfide (NCS) nanostructure was employed as a robust microwave absorber, which displayed an optimized reflection loss of  ‑49.1 dB in the gigahertz range with a loading of only 20 wt% in an NCS/paraffin wax composite. High electrical conductivity was found to contribute prominent conductive loss in NCS, leading to intense dielectric loss within a relatively low mass loading. Furthermore, owing to its high electrical conductivity and remarkable dielectric loss to microwaves, the prepared NCS exhibited excellent performance in EMI shielding. The EMI shielding efficiency of the 50 wt% NCS/paraffin composite exceeded 55 dB at the X-band, demonstrating NCS is a versatile candidate for solving EMI problems.

Investigating service features to sustain engagement in early intervention mental health services.

Science.gov (United States)

Becker, Mackenzie; Cunningham, Charles E; Christensen, Bruce K; Furimsky, Ivana; Rimas, Heather; Wilson, Fiona; Jeffs, Lisa; Madsen, Victoria; Bieling, Peter; Chen, Yvonne; Mielko, Stephanie; Zipursky, Robert B

2017-08-23

To understand what service features would sustain patient engagement in early intervention mental health treatment. Mental health patients, family members of individuals with mental illness and mental health professionals completed a survey consisting of 18 choice tasks that involved 14 different service attributes. Preferences were ascertained using importance and utility scores. Latent class analysis revealed segments characterized by distinct preferences. Simulations were carried out to estimate utilization of hypothetical clinical services. Overall, 333 patients and family members and 183 professionals (N = 516) participated. Respondents were distributed between a Professional segment (53%) and a Patient segment (47%) that differed in a number of their preferences including for appointment times, individual vs group sessions and mode of after-hours support. Members of both segments shared preferences for many of the service attributes including having crisis support available 24 h per day, having a choice of different treatment modalities, being offered help for substance use problems and having a focus on improving symptoms rather than functioning. Simulations predicted that 60% of the Patient segment thought patients would remain engaged with a Hospital service, while 69% of the Professional segment thought patients would be most likely to remain engaged with an E-Health service. Patients, family members and professionals shared a number of preferences about what service characteristics will optimize patient engagement in early intervention services but diverged on others. Providing effective crisis support as well as a range of treatment options should be prioritized in the future design of early intervention services. © 2017 John Wiley & Sons Australia, Ltd.

Ionosphere Waves Service - A demonstration

Science.gov (United States)

Crespon, François

2013-04-01

In the frame of the FP7 POPDAT project the Ionosphere Waves Service was developed by ionosphere experts to answer several questions: How make the old ionosphere missions more valuable? How provide scientific community with a new insight on wave processes that take place in the ionosphere? The answer is a unique data mining service accessing a collection of topical catalogues that characterize a huge number of Atmospheric Gravity Waves, Travelling Ionosphere Disturbances and Whistlers events. The Ionosphere Waves Service regroups databases of specific events extracted by experts from a ten of ionosphere missions which end users can access by applying specific searches and by using statistical analysis modules for their domain of interest. The scientific applications covered by the IWS are relative to earthquake precursors, ionosphere climatology, geomagnetic storms, troposphere-ionosphere energy transfer, and trans-ionosphere link perturbations. In this presentation we propose to detail the service design, the hardware and software architecture, and the service functions. The service interface and capabilities will be the focus of a demonstration in order to help potential end-users for their first access to the Ionosphere Waves Service portal. This work is made with the support of FP7 grant # 263240.

Synthesis, spectral characterization, thermal and photoluminescence properties of Zn(II) and Cd(II)-azido/thiocyanato complexes with thiazolylazo dye and 1,2-bis(diphenylphoshino)ethane.

Science.gov (United States)

Yamgar, B A; Sawant, V A; Bharate, B G; Chavan, S S

2011-01-01

A series of complexes of the type [M(L)(dppe)X2]; where M=Zn(II) or Cd(II); L=4-(2'-thiazolylazo)chlorobenzene (L1), 4-(2'-thiazolylazo)bromobenzene (L2) and 4-(2'-thiazolylazo) iodobenzene (L3); dppe=1,2-bis(diphenylphosphino)ethane; X=N3- or NCS- have been prepared and characterized on the basis of their microanalysis, molar conductance, thermal, IR, UV-vis and 1H NMR spectral studies. IR spectra show that the ligand L is coordinated to the metal atom in bidentate manner via azo nitrogen and thiazole nitrogen. An octahedral structure is proposed for all the complexes. The thermal behavior of the complexes revealed that the thiocyanato complexes are thermally more stable than the azido complexes. All the complexes exhibit blue-green emission with high quantum yield as the result of the fluorescence from the intraligand emission excited state. Copyright © 2010 Elsevier B.V. All rights reserved.

A facile and low cost synthesis of earth abundant element Cu{sub 2}ZnSnS{sub 4} (CZTS) nanocrystals: Effect of Cu concentrations

Energy Technology Data Exchange (ETDEWEB)

Shin, Seung Wook; Han, Jun Hee [Department of Materials Science and Engineering, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Park, Chan Yeong; Kim, Sae-Rok; Park, Yeon Chan; Agawane, G.L. [Photonics Technology Research Institute, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-Dong, Buk-Gu, Gwangju 500-757 (Korea, Republic of); Moholkar, A.V. [Electrochemical Mat. Lab, Department of Physics, Shivaji University, Kolhapur 416-004 (India); Yun, Jae Ho [Photovoltaic Research Group, Korea Institute of Energy Research, 71-2 Jang-Dong, Yuseong-Gu, Daejeon 305-343 (Korea, Republic of); Jeong, Chae Hwan [Solar City Center, Development of Advanced Components and Materials Korea Institute of Industrial Technology, Gwangju 500-480 (Korea, Republic of); Lee, Jeong Yong, E-mail: j.y.lee@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, 335 Gwahangno, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Kim, Jin Hyeok, E-mail: jinhyeok@chonnam.ac.kr [Photonics Technology Research Institute, Department of Materials Science and Engineering, Chonnam National University, 300 Yongbong-Dong, Buk-Gu, Gwangju 500-757 (Korea, Republic of)

2012-11-15

Highlights: Black-Right-Pointing-Pointer Cu{sub 2}ZnSnS{sub 4} (CZTS) nanocrystals (NCs) were prepared by sulfurization of microwave assisted precursor without toxic chemicals. Black-Right-Pointing-Pointer Effect of Cu concentration on the properties of CZTS NCs was investigated using various analysis methods. Black-Right-Pointing-Pointer The properties of CZTS NCs was strongly related to the Cu concentrations. - Abstract: Cu{sub 2}ZnSnS{sub 4} (CZTS) nanocrystals (NCs) were synthesized by sulfurization of microwave assisted precursor powders without toxic chemicals. The effects of different Cu concentration from 0.01 to 0.025 M on the structural, morphological, compositional, chemical and optical properties of CZTS NCs were investigated. X-ray diffraction patterns, X-ray photoelectron spectroscopy and transmission electron microscopy results showed that the precursor powder contains several broad peaks that could not be assigned to CZTS, ZnS, Cu{sub 2-x}S, Sn{sub 2}S{sub 3} and Cu{sub 2}SnS{sub 3}. However, the sulfurized NCs showed both kesterite CZTS and Cu- and Sn-based secondary phases except for that formed at Cu concentration of 0.02 M. Inductively coupled plasma (ICP) results showed that the presence of Cu in the sulfurized CZTS NCs increased with increasing Cu concentration from 16.57 to 32.94 at.% while Zn and Sn in the sulfurized CZTS NCs decreased with increasing Cu concentration. UV-Vis spectroscopy results showed that the absorption coefficient of the sulfurized NCs was over 10{sup 4} cm{sup -1} in the visible region and band gap energy of the sulfurized CZTS NCs decreased from 1.65 to 1.28 eV with increasing Cu concentration.

From theoretical to actual ecosystem services: mapping beneficiaries and spatial flows in ecosystem service assessments

Directory of Open Access Journals (Sweden)

Kenneth J. Bagstad

2014-06-01

Full Text Available Ecosystem services mapping and modeling has focused more on supply than demand, until recently. Whereas the potential provision of economic benefits from ecosystems to people is often quantified through ecological production functions, the use of and demand for ecosystem services has received less attention, as have the spatial flows of services from ecosystems to people. However, new modeling approaches that map and quantify service-specific sources (ecosystem capacity to provide a service, sinks (biophysical or anthropogenic features that deplete or alter service flows, users (user locations and level of demand, and spatial flows can provide a more complete understanding of ecosystem services. Through a case study in Puget Sound, Washington State, USA, we quantify and differentiate between the theoretical or in situ provision of services, i.e., ecosystems' capacity to supply services, and their actual provision when accounting for the location of beneficiaries and the spatial connections that mediate service flows between people and ecosystems. Our analysis includes five ecosystem services: carbon sequestration and storage, riverine flood regulation, sediment regulation for reservoirs, open space proximity, and scenic viewsheds. Each ecosystem service is characterized by different beneficiary groups and means of service flow. Using the ARtificial Intelligence for Ecosystem Services (ARIES methodology we map service supply, demand, and flow, extending on simpler approaches used by past studies to map service provision and use. With the exception of the carbon sequestration service, regions that actually provided services to people, i.e., connected to beneficiaries via flow paths, amounted to 16-66% of those theoretically capable of supplying services, i.e., all ecosystems across the landscape. These results offer a more complete understanding of the spatial dynamics of ecosystem services and their effects, and may provide a sounder basis for

From theoretical to actual ecosystem services: mapping beneficiaries and spatial flows in ecosystem service assessments

Science.gov (United States)

Bagstad, Kenneth J.; Villa, Ferdinando; Batker, David; Harrison-Cox, Jennifer; Voigt, Brian; Johnson, Gary W.

2014-01-01

Ecosystem services mapping and modeling has focused more on supply than demand, until recently. Whereas the potential provision of economic benefits from ecosystems to people is often quantified through ecological production functions, the use of and demand for ecosystem services has received less attention, as have the spatial flows of services from ecosystems to people. However, new modeling approaches that map and quantify service-specific sources (ecosystem capacity to provide a service), sinks (biophysical or anthropogenic features that deplete or alter service flows), users (user locations and level of demand), and spatial flows can provide a more complete understanding of ecosystem services. Through a case study in Puget Sound, Washington State, USA, we quantify and differentiate between the theoretical or in situ provision of services, i.e., ecosystems’ capacity to supply services, and their actual provision when accounting for the location of beneficiaries and the spatial connections that mediate service flows between people and ecosystems. Our analysis includes five ecosystem services: carbon sequestration and storage, riverine flood regulation, sediment regulation for reservoirs, open space proximity, and scenic viewsheds. Each ecosystem service is characterized by different beneficiary groups and means of service flow. Using the ARtificial Intelligence for Ecosystem Services (ARIES) methodology we map service supply, demand, and flow, extending on simpler approaches used by past studies to map service provision and use. With the exception of the carbon sequestration service, regions that actually provided services to people, i.e., connected to beneficiaries via flow paths, amounted to 16-66% of those theoretically capable of supplying services, i.e., all ecosystems across the landscape. These results offer a more complete understanding of the spatial dynamics of ecosystem services and their effects, and may provide a sounder basis for economic

Testing a "content meets process" model of depression vulnerability and rumination: Exploring the moderating role of set-shifting deficits.

Science.gov (United States)

Vergara-Lopez, Chrystal; Lopez-Vergara, Hector I; Roberts, John E

2016-03-01

MacCoon and Newman's (2006) "content meets process" model posits that deficits in cognitive control make it difficult to disengage from negative cognitions caused by a negative cognitive style (NCS). The present study examined if the interactive effect of cognitive set-shifting abilities and NCS predicts rumination and past history of depression. Participants were 90 previously depressed individuals and 95 never depressed individuals. We administered three laboratory tasks that assess set-shifting: the Wisconsin Card-Sorting Task, the Emotional Card-Sorting Task, and the Internal Switch Task, and self-report measures of NCS and rumination. Shifting ability in the context of emotional distractors moderated the association between NCS and depressive rumination. Although previously depressed individuals had more NCS and higher trait rumination relative to never depressed individuals, shifting ability did not moderate the association between NCS and depression history. The cross-sectional correlational design cannot address the causal direction of effects. It is also not clear whether findings will generalize beyond college students. NCS was elevated in previously depressed individuals consistent with its theoretical role as trait vulnerability to the disorder. Furthermore, NCS may be particularly likely to trigger rumination among individuals with poor capacity for cognitive control in the context of emotional distraction. Copyright © 2015 Elsevier Ltd. All rights reserved.

Violet-blue photoluminescence from Si nanoparticles with zinc-blende structure synthesized by laser ablation in liquids

Directory of Open Access Journals (Sweden)

P. Liu

2013-02-01

Full Text Available Violet-blue luminescence from Si nanostructures has been widely investigated, because of its potential use in optoelectronic and bioimaging devices. However, the emission mechanism in multiform Si nanomaterials remains unclear. In this contribution, Si nanocrystals (NCs with zincblende structure and visible violet-blue emission are prepared by electric field assisted laser ablation in liquids. While subsequent annealing of the Si NCs weakens their blue emission dramatically. We investigate the origin of the violet-blue emission by monitoring crystal structure transitions and photoluminescence during different treatments of the Si NCs. The results indicate that the violet-blue emission cannot simply be ascribed to quantum confinement effects or the presence of general surface states on the Si NCs. Instead, we propose that excitons are formed within the Si NCs by direct transitions at Γ or X points, which can be induced during the formation of the zincblende structure, and are a most possible origin of the violet-blue luminescence. Furthermore, defects in the metastable Si NCs are also expected to play an important role in violet-blue emission. This study not only gives clear and general insight into the physical origins of violet-blue emission from Si NCs, it also provides useful information for designing optoelectronic devices based on Si NCs.

Charge trapping of Ge-nanocrystals embedded in TaZrO{sub x} dielectric films

Energy Technology Data Exchange (ETDEWEB)

Lehninger, D., E-mail: David.Lehninger@physik.tu-freiberg.de; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J. [Institute of Applied Physics, TU Bergakademie Freiberg, D-09596 Freiberg (Germany); Klemm, V.; Rafaja, D. [Institute of Materials Science, TU Bergakademie Freiberg, D-09596 Freiberg (Germany); Borany, J. von [Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01314 Dresden (Germany)

2015-01-12

Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO{sub x} by thermal annealing of co-sputtered Ge-TaZrO{sub x} layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window.

Charge trapping of Ge-nanocrystals embedded in TaZrOx dielectric films

International Nuclear Information System (INIS)

Lehninger, D.; Seidel, P.; Geyer, M.; Schneider, F.; Heitmann, J.; Klemm, V.; Rafaja, D.; Borany, J. von

2015-01-01

Ge-nanocrystals (NCs) were synthesized in amorphous TaZrO x by thermal annealing of co-sputtered Ge-TaZrO x layers. Formation of spherical shaped Ge-NCs with small variation of size, areal density, and depth distribution was confirmed by high-resolution transmission electron microscopy. The charge storage characteristics of the Ge-NCs were investigated by capacitance-voltage and constant-capacity measurements using metal-insulator-semiconductor structures. Samples with Ge-NCs exhibit a maximum memory window of 5 V by sweeping the bias voltage from −7 V to 7 V and back. Below this maximum, the width of the memory window can be controlled by the bias voltage. The fitted slope of the memory window versus bias voltage characteristics is very close to 1 for samples with one layer Ge-NCs. A second layer Ge-NCs does not result in a second flat stair in the memory window characteristics. Constant-capacity measurements indicate charge storage in trapping centers at the interfaces between the Ge-NCs and the surrounding materials (amorphous matrix/tunneling oxide). Charge loss occurs by thermal detrapping and subsequent band-to-band tunneling. Reference samples without Ge-NCs do not show any memory window

Highly Emissive Divalent-Ion-Doped Colloidal CsPb1–xMxBr3 Perovskite Nanocrystals through Cation Exchange

Science.gov (United States)

2017-01-01

Colloidal CsPbX3 (X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX3 NCs. Here, we present a method that allows partial cation exchange in colloidal CsPbBr3 NCs, whereby Pb2+ is exchanged for several isovalent cations, resulting in doped CsPb1–xMxBr3 NCs (M= Sn2+, Cd2+, and Zn2+; 0 50%), sharp absorption features, and narrow emission of the parent CsPbBr3 NCs. The blue-shift in the optical spectra is attributed to the lattice contraction that accompanies the Pb2+ for M2+ cation exchange and is observed to scale linearly with the lattice contraction. This work opens up new possibilities to engineer the properties of halide perovskite NCs, which to date are demonstrated to be the only known system where cation and anion exchange reactions can be sequentially combined while preserving the original NC shape, resulting in compositionally diverse perovskite NCs. PMID:28260380

Broadband enhancement of photoluminance from colloidal metal halide perovskite nanocrystals on plasmonic nanostructured surfaces.

Science.gov (United States)

Zhang, Si; Liang, Yuzhang; Jing, Qiang; Lu, Zhenda; Lu, Yanqing; Xu, Ting

2017-11-07

Metal halide perovskite nanocrystals (NCs) as a new kind of promising optoelectronic material have attracted wide attention due to their high photoluminescence (PL) quantum yield, narrow emission linewidth and wideband color tunability. Since the PL intensity always has a direct influence on the performance of optoelectronic devices, it is of vital importance to improve the perovskite NCs' fluorescence emission efficiency. Here, we synthesize three inorganic perovskite NCs and experimentally demonstrate a broadband fluorescence enhancement of perovskite NCs by exploiting plasmonic nanostructured surface consisting of nanogrooves array. The strong near-field optical localization associated with surface plasmon polariton-coupled emission effect generated by the nanogrooves array can significantly boost the absorption of perovskite NCs and tailor the fluorescence emissions. As a result, the PL intensities of perovskite NCs are broadband enhanced with a maximum factor higher than 8-fold achieved in experimental demonstration. Moreover, the high efficiency PL of perovskite NCs embedded in the polymer matrix layer on the top of plasmonic nanostructured surface can be maintained for more than three weeks. These results imply that plasmonic nanostructured surface is a good candidate to stably broadband enhance the PL intensity of perovskite NCs and further promote their potentials in the application of visible-light-emitting devices.

Facile Synthesis of Gd-Functionalized Gold Nanoclusters as Potential MRI/CT Contrast Agents

Directory of Open Access Journals (Sweden)

Wenjun Le

2016-04-01

Full Text Available Multi-modal imaging plays a key role in the earlier detection of disease. In this work, a facile bioinspired method was developed to synthesize Gd-functionalized gold nanoclusters (Gd-Au NCs. The Gd-Au NCs exhibit a uniform size, with an average size of 5.6 nm in dynamic light scattering (DLS, which is a bit bigger than gold clusters (3.74 nm, DLS, while the fluorescent properties of Gd-Au NCs are almost the same as that of Au NCs. Moreover, the Gd-Au NCs exhibit a high longitudinal relaxivity value (r1 of 22.111 s−1 per mM of Gd in phosphate-buffered saline (PBS, which is six times higher than that of commercial Magnevist (A complex of gadolinium with a chelating agent, diethylenetriamine penta-acetic acid, Gd-DTPA, r1 = 3.56 mM−1·s−1. Besides, as evaluated by nano single photon emission computed tomography (SPECT and computed tomography (CT the Gd-Au NCs have a potential application as CT contrast agents because of the Au element. Finally, the Gd-Au NCs show little cytotoxicity, even when the Au concentration is up to 250 μM. Thus, the Gd-Au NCs can act as multi-modal imaging contrast agents.

Monochromatic and electrochemically switchable electrochemiluminescence of perovskite CsPbBr3 nanocrystals.

Science.gov (United States)

Huang, Yan; Fang, Mingxiang; Zou, Guizheng; Zhang, Bin; Wang, Huaisheng

2016-11-10

Cubic-shaped perovskite CsPbBr 3 nanocrystals (NCs) could be electrochemically injected with holes (or electrons) to produce several charged states under different oxidizing and reducing potentials, and then bring out electrochemiluminescence (ECL) of higher color purity than traditional ECL chemicals and metal chalcogenide NCs, in both annihilation and co-reactant routes. The difference of electrochemical gaps between varied hole and electron injecting potentials displayed little effect on the ECL spectrum and colour purity of CsPbBr 3 NCs. All the excited states generated under different oxidizing and reducing potential couples in ECL of CsPbBr 3 NCs were the same as those in photoluminescence, as all the ECL spectra were almost identical to the CsPbBr 3 NCs' photoluminescence spectrum. Importantly, the ECL of CsPbBr 3 NCs was electrochemically switchable and displayed an obvious "on/off" type feature by changing the sequence of hole injecting and electron injecting processes, as strong ECL could be obtained by injecting holes onto the electron injected NCs, while no or very weak ECL was obtained in the reversed way.

Analysis of phases in the structure determination of an icosahedral virus

Energy Technology Data Exchange (ETDEWEB)

Plevka, Pavel; Kaufmann, Bärbel; Rossmann, Michael G. (Purdue)

2012-03-15

The constraints imposed on structure-factor phases by noncrystallographic symmetry (NCS) allow phase improvement, phase extension to higher resolution and hence ab initio phase determination. The more numerous the NCS redundancy and the greater the volume used for solvent flattening, the greater the power for phase determination. In a case analyzed here the icosahedral NCS phasing appeared to have broken down, although later successful phase extension was possible when the envelope around the NCS region was tightened. The phases from the failed phase-determination attempt fell into four classes, all of which satisfied the NCS constraints. These four classes corresponded to the correct solution, opposite enantiomorph, Babinet inversion and opposite enantiomorph with Babinet inversion. These incorrect solutions can be seeded from structure factors belonging to reciprocal-space volumes that lie close to icosahedral NCS axes where the structure amplitudes tend to be large and the phases tend to be 0 or {pi}. Furthermore, the false solutions can spread more easily if there are large errors in defining the envelope designating the region in which NCS averaging is performed.

Protein coated gold nanoparticles as template for the directed synthesis of highly fluorescent gold nanoclusters

Science.gov (United States)

Zhang, Lingyan; Han, Fei

2018-04-01

Bovine serum albumin (BSA) modified gold nanoparticles (AuNPs) was selected as template for the synthesis of AuNPs@gold nanoclusters (AuNCs) core/shell nanoparticles, in which BSA not only acted as dual functions agent for both anchoring and reducing Au3+ ions, but also was employed as a bridge between the AuNPs and AuNCs. Optical properties of AuNPs@AuNCs core/shell nanoparticles were studied using UV-visible and fluorescence spectroscopy. The prepared AuNPs@AuNCs core/shell nanoparticles exhibited sphere size uniformity with improved monodispersity, excellent fluorescence and fluorescent stability. Compared with AuNCs, AuNPs@AuNCs core/shell nanoparticles possessed large size and strong fluorescence intensity due to the effect of AuNPs as core. Moreover, the mechanism of the AuNPs induced fluorescence changes of the core/shell nanoparticles was first explored.

Self-assembled nanocomplexes of anionic pullulan and polyallylamine for DNA and pH-sensitive intracellular drug delivery

Science.gov (United States)

Vora, Lalit; Tyagi, Monica; Patel, Ketan; Gupta, Sanjay; Vavia, Pradeep

2014-12-01

The amalgamation of chemotherapy and gene therapy is promising treatment option for cancer. In this study, novel biocompatible self-assembled nanocomplexes (NCs) between carboxylmethylated pullulan t335 (CMP) with polyallylamine (CMP-PAA NCs) were developed for plasmid DNA (pDNA) and pH-sensitive doxorubicin (DOX) delivery. DOX was conjugated to CMP (DOX-CMP) via hydrazone and confirmed by FTIR and 1H-NMR. In vitro release studies of pH-sensitive DOX-CMP conjugate showed 23 and 85 % release after 48 h at pH 7.4 (physiological pH) and pH 5 (intracellular/tumoral pH), respectively. The CMP-PAA NCs or DOX-CMP-PAA NCs self-assembled into a nanosized (successful cellular uptake of DOX-CMP-PAA NCs in HEK293 cells. Thus, NCs hold great potential for targeted pDNA and pH-sensitive intratumoral drug delivery.

Structural, optical and Carrier dynamics of self-assembled InGaN nanocolumns on Si(111)

Science.gov (United States)

Kumar, Praveen; Devi, Pooja; Soto Rodriguez, P. E. D.; Jain, Rishabh; Jaggi, Neena; Sinha, R. K.; Kumar, Mahesh

2018-05-01

We investigated the morphological, structural, optical, electrical and carrier relaxation dynamic changes on the self-assembled grown InGaN nanocolumns (NCs) directly on p-Si(111) substrate at two different substrate temperature, namely 580 °C (A) and 500 °C (B). The emission wavelength of comparably low temperature (LT) grown NCs was red-shifted from 3.2eV to 2.4eV. First observations on the charge carrier dynamics of these directly grown NCs show comparable broad excited state absorption (ESA) for LT gown NCs, which manifest bi-exponential decay due to the radiative defects generated during the coalescence of these NCs.

High-Density Stacked Ru Nanocrystals for Nonvolatile Memory Application

International Nuclear Information System (INIS)

Ping, Mao; Zhi-Gang, Zhang; Li-Yang, Pan; Jun, Xu; Pei-Yi, Chen

2009-01-01

Stacked ruthenium (Ru) nanocrystals (NCs) are formed by rapid thermal annealing for the whole gate stacks and embedded in memory structure, which is compatible with conventional CMOS technology. Ru NCs with high density (3 × 10 12 cm −2 ), small size (2–4 nm) and good uniformity both in aerial distribution and morphology are formed. Attributed to the higher surface trap density, a memory window of 5.2 V is obtained with stacked Ru NCs in comparison to that of 3.5 V with single-layer samples. The stacked Ru NCs device also exhibits much better retention performance because of Coulomb blockade and vertical uniformity between stacked Ru NCs

New camera systems for fuel services

International Nuclear Information System (INIS)

Hummel, W.; Beck, H.J.

2010-01-01

AREVA NP Fuel Services have many years of experience in visual examination and measurements on fuel assemblies and associated core components by using state of the art cameras and measuring technologies. The used techniques allow the surface and dimensional characterization of materials and shapes by visual examination. New enhanced and sophisticated technologies for fuel services f. e. are two shielded color camera systems for use under water and close inspection of a fuel assembly. Nowadays the market requirements for detecting and characterization of small defects (lower than the 10th of one mm) or cracks and analyzing surface appearances on an irradiated fuel rod cladding or fuel assembly structure parts have increased. Therefore it is common practice to use movie cameras with higher resolution. The radiation resistance of high resolution CCD cameras is in general very low and it is not possible to use them unshielded close to a fuel assembly. By extending the camera with a mirror system and shielding around the sensitive parts, the movie camera can be utilized for fuel assembly inspection. AREVA NP Fuel Services is now equipped with such kind of movie cameras. (orig.)

Distinct metal-exchange pathways of doped Ag25 nanoclusters

KAUST Repository

Bootharaju, Megalamane Siddaramappa; Sinatra, Lutfan; Bakr, Osman

2016-01-01

Atomically precise metal nanoclusters (NCs) containing more than one type of metal atom (i.e., doped or alloyed), due to synergistic effects, open new avenues for engineering the catalytic and optical properties of NCs in a manner that homometal NCs

Carbon-Based Fe3O4 Nanocomposites Derived from Waste Pomelo Peels for Magnetic Solid-Phase Extraction of 11 Triazole Fungicides in Fruit Samples

Science.gov (United States)

Ren, Keyu; Zhang, Wenlin; Cao, Shurui; Wang, Guomin; Zhou, Zhiqin

2018-01-01

Carbon-based Fe3O4 nanocomposites (C/Fe3O4 NCs) were synthesized by a simple one-step hydrothermal method using waste pomelo peels as the carbon precursors. The characterization results showed that they had good structures and physicochemical properties. The prepared C/Fe3O4 NCs could be applied as excellent and recyclable adsorbents for magnetic solid phase extraction (MSPE) of 11 triazole fungicides in fruit samples. In the MSPE procedure, several parameters including the amount of adsorbents, extraction time, the type and volume of desorption solvent, and desorption time were optimized in detail. Under the optimized conditions, the good linearity (R2 > 0.9916), the limits of detection (LOD), and quantification (LOQ) were obtained in the range of 1–100, 0.12–0.55, and 0.39–1.85 μg/kg for 11 pesticides, respectively. Lastly, the proposed MSPE method was successfully applied to analyze triazole fungicides in real apple, pear, orange, peach, and banana samples with recoveries in the range of 82.1% to 109.9% and relative standard deviations (RSDs) below 8.4%. Therefore, the C/Fe3O4 NCs based MSPE method has a great potential for isolating and pre-concentrating trace levels of triazole fungicides in fruits. PMID:29734765

A transparent flexible z-axis sensitive multi-touch panel based on colloidal ITO nanocrystals.

Science.gov (United States)

Sangeetha, N M; Gauvin, M; Decorde, N; Delpech, F; Fazzini, P F; Viallet, B; Viau, G; Grisolia, J; Ressier, L

2015-08-07

Bottom-up fabrication of a flexible multi-touch panel prototype based on transparent colloidal indium tin oxide (ITO) nanocrystal (NC) films is presented. A series of 7% Sn(4+) doped ITO NCs protected by oleate, octanoate and butanoate ligands are synthesized and characterized by a battery of techniques including, high resolution transmission electron microscopy, X-ray diffraction, (1)H, (13)C and (119)Sn nuclear magnetic resonance spectroscopy, and the related diffusion ordered spectroscopy. Electrical resistivities of transparent films of these NCs assembled on flexible polyethylene terephthalate substrates by convective self-assembly from their suspension in toluene decrease with the ligand length, from 220 × 10(3) for oleate ITO to 13 × 10(3)Ω cm for butanoate ITO NC films. A highly transparent, flexible touch panel based on a matrix of strain gauges derived from the least resistive film of 17 nm butanoate ITO NCs sensitively detects the lateral position (x, y) of the touch as well as its intensity over the z-axis. Being compatible with a stylus or bare/gloved finger, a larger version of this module may be readily implemented in upcoming flexible screens, enabling navigation capabilities over all three axes, a feature highly desired by the display industry.

A novel bio-degradable polymer stabilized Ag/TiO2 nanocomposites and their catalytic activity on reduction of methylene blue under natural sun light.

Science.gov (United States)

Geetha, D; Kavitha, S; Ramesh, P S

2015-11-01

In the present work we defined a novel method of TiO2 doped silver nanocomposite synthesis and stabilization using bio-degradable polymers viz., chitosan (Cts) and polyethylene glycol (PEG). These polymers are used as reducing agents. The instant formation of AgNPs was analyzed by visual observation and UV-visible spectrophotometer. TiO2 nanoparticles doped at different concentrations viz., 0.03, 0.06 and 0.09mM on PEG/Cts stabilized silver (0.04wt%) were successfully synthesized. This study presents a simple route for the in situ synthesis of both metal and polymer confined within the nanomaterial, producing ternary hybrid inorganic-organic nanomaterials. The results reveal that they have higher photocatalytic efficiencies under natural sun light. The synthesized TiO2 doped Ag nanocomposites (NCs) were characterized by SEM/EDS, TEM, XRD, FTIR and DLS with zeta potential. The stability of Ag/TiO2 nanocomposite is due to the high negative values of zeta potential and capping of constituents present in the biodegradable polymer which is evident from zeta potential and FT-IR studies. The XRD and EDS pattern of synthesized Ag/TiO2 NCs showed their crystalline structure, with face centered cubic geometry oriented in (111) plane. AFM and DLS studies revealed that the diameter of stable Ag/TiO2 NCs was approximately 35nm. Moreover the catalytic activity of synthesize Ag/TiO2 NCs in the reduction of methylene blue was studied by UV-visible spectrophotometer. The synthesized Ag/TiO2 NCs are observed to have a good catalytic activity on the reduction of methylene blue by bio-degradable which is confirmed by the decrease in absorbance maximum value of methylene blue with respect to time using UV-vis spectrophotometer. The significant enhancement in the photocatalytic activity of Ag/TiO2 nanocomposites under sun light irradiation can be ascribed to the effect of noble metal Ag by acting as electron traps in TiO2 band gap. Copyright © 2015. Published by Elsevier Inc.

Prospects of Colloidal Copper Chalcogenide Nanocrystals

NARCIS (Netherlands)

van der Stam, W.; Berends, A.C.; de Mello-Donega, Celso

2016-01-01

Over the past few years, colloidal copper chalcogenide nanocrystals (NCs) have emerged as promising alternatives to conventional Cd and Pb chalcogenide NCs. Owing to their wide size, shape, and composition tunability, Cu chalcogenide NCs hold great promise for several applications, such as

Revised analysis of in-migrating workers during site characterization

International Nuclear Information System (INIS)

1987-10-01

The Deaf Smith Environmental Assessment's analysis of in-migrating workers and community service impacts was predicated on the assumption that a peak of approximately 480 workers would be needed on location to conduct site characterization activities. This analysis assumed that DOE's prime contractor(s) would have a limited staff in the area; the majority of the workers would be on site for the construction of the exploratory shaft and to conduct geologic and environmental studies. Since the time when the Environmental Assessment was prepared, the prime contractors [Battelle-ISSC and the Technical Field Service Contractor (TFSC)] were requested to move their offices to the site area. Therefore, many more administrative and technical workers would be expected to relocate in the Deaf Smith County regions. A change in the expected number of in-migrants could also change the expected nature of community service impacts. It is the purpose of this analysis to evaluate the site characterization workforce and thresholds for local community services. 22 refs., 24 tabs

Oral administration of iron-saturated bovine lactoferrin-loaded ceramic nanocapsules for breast cancer therapy and influence on iron and calcium metabolism.

Science.gov (United States)

Mahidhara, Ganesh; Kanwar, Rupinder K; Roy, Kislay; Kanwar, Jagat R

2015-01-01

We determined the anticancer efficacy and internalization mechanism of our polymeric-ceramic nanoparticle system (calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate nanocapsules/nanocarriers [ACSC NCs]) loaded with iron-saturated bovine lactoferrin (Fe-bLf) in a breast cancer xenograft model. ACSC-Fe-bLf NCs with an overall size of 322±27.2 nm were synthesized. In vitro internalization and anticancer efficacy were evaluated in the MDA-MB-231 cells using multicellular tumor spheroids, CyQUANT and MTT assays. These NCs were orally delivered in a breast cancer xenograft mice model, and their internalization, cytotoxicity, biodistribution, and anticancer efficacy were evaluated. Chitosan-coated calcium phosphate Fe-bLf NCs effectively (59%, P≤0.005) internalized in a 1-hour period using clathrin-mediated endocytosis (P≤0.05) and energy-mediated pathways (P≤0.05) for internalization; 3.3 mg/mL of ACSC-Fe-bLf NCs completely disintegrated (~130-fold reduction, P≤0.0005) the tumor spheroids in 72 hours and 96 hours. The IC50 values determined for ACSC-Fe-bLf NCs were 1.69 mg/mL at 10 hours and 1.62 mg/mL after 20 hours. We found that Fe-bLf-NCs effectively (P≤0.05) decreased the tumor size (4.8-fold) compared to the void NCs diet and prevented tumor recurrence when compared to intraperitoneal injection of Taxol and Doxorubicin. Receptor gene expression and micro-RNA analysis confirmed upregulation of low-density lipoprotein receptor and transferrin receptor (liver, intestine, and brain). Several micro-RNAs responsible for iron metabolism upregulated with NCs were identified. Taken together, orally delivered Fe-bLf NCs offer enhanced antitumor activity in breast cancer by internalizing via low-density lipoprotein receptor and transferrin receptor and regulating the micro-RNA expression. These NCs also restored the body iron and calcium levels and increased the hematologic counts.

A Web Service and Interface for Remote Electronic Device Characterization

Science.gov (United States)

Dutta, S.; Prakash, S.; Estrada, D.; Pop, E.

2011-01-01

A lightweight Web Service and a Web site interface have been developed, which enable remote measurements of electronic devices as a "virtual laboratory" for undergraduate engineering classes. Using standard browsers without additional plugins (such as Internet Explorer, Firefox, or even Safari on an iPhone), remote users can control a Keithley…

Selective Killing of Breast Cancer Cells by Doxorubicin-Loaded Fluorescent Gold Nanoclusters: Confocal Microscopy and FRET.

Science.gov (United States)

Chattoraj, Shyamtanu; Amin, Asif; Jana, Batakrishna; Mohapatra, Saswat; Ghosh, Surajit; Bhattacharyya, Kankan

2016-01-18

Fluorescent gold nanoclusters (AuNCs) capped with lysozymes are used to deliver the anticancer drug doxorubicin to cancer and noncancer cells. Doxorubicin-loaded AuNCs cause the highly selective and efficient killing (90 %) of breast cancer cells (MCF7) (IC50 =155 nm). In contrast, the killing of the noncancer breast cells (MCF10A) by doxorubicin-loaded AuNCs is only 40 % (IC50 =4500 nm). By using a confocal microscope, the fluorescence spectrum and decay of the AuNCs were recorded inside the cell. The fluorescence maxima (at ≈490-515 nm) and lifetime (≈2 ns), of the AuNCs inside the cells correspond to Au10-13 . The intracellular release of doxorubicin from AuNCs is monitored by Förster resonance energy transfer (FRET) imaging. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Layered rare-earth hydroxide nanocones with facile host composition modification and anion-exchange feature: topotactic transformation into oxide nanocones for upconversion.

Science.gov (United States)

Zhong, Yishun; Chen, Gen; Liu, Xiaohe; Zhang, Dan; Zhang, Ning; Li, Junhui; Liang, Shuquan; Ma, Renzhi; Qiu, Guanzhou

2017-06-22

Conical structures with hollow interiors, namely, nanocones (NCs), may exhibit better carrier transport properties than nanorods or nanotubes, which make them promising candidates for potential applications in optical/display devices, electronics and optoelectronics. Generally, conical structures belong to a metastable state between lamellar and tubular forms due to the extreme curvature causing the increase of internal strain energy. Therefore, it is very difficult to prepare NCs in high yield and purity under mild conditions. Here we firstly demonstrate a general strategy for the synthesis of layered rare-earth hydroxide (LRH) NCs intercalating dodecyl sulfate anions (C 12 H 25 SO 4 - , DS - ) using hexamethylenetetramine (C 6 H 12 N 4 , HMT) hydrolysis. The rare-earth cations (RE 3+ ) in the host layer can be conveniently modified and/or doped, resulting in a large family of monometallic (Y, Tb, Er), bi- (Y-Tb, Y-Er) and even tri-metallic (Y-Yb-Er) LRH NCs with adjustable ratios. Moreover, the DS - -intercalated LRH NCs can be readily modified with various inorganic or organic anions (e.g., NO 3 - , Cl - , and CH 3 COO - , etc.) through a conventional anion-exchange procedure, and the original conical morphology can be perfectly maintained. The anion-exchanged product, for example, NO 3 - -intercalated NCs, can be more easily and topotactically transformed into oxide NCs than the original DS - -intercalated form, exempt from the formation of rare-earth oxysulfates induced by the combustion of interlayer DS anions. Taking advantage of this protocol, tri-metallic (Y-Yb-Er) LRH NCs were anion-exchanged into the NO 3 - -intercalated form and subsequently calcined into Y 2 O 3 :Yb,Er oxide NCs, which showed efficient upconversion photoluminescence properties. The current strategy may become a general method for the designed synthesis of other related hydroxide and oxide NCs for a wide range of potential applications.

Mechanistic insights into the photocatalytic properties of metal nanocluster/graphene ensembles. Examining the role of visible light in the reduction of 4-nitrophenol.

Science.gov (United States)

Koklioti, Malamatenia A; Skaltsas, Theodosis; Sato, Yuta; Suenaga, Kazu; Stergiou, Anastasios; Tagmatarchis, Nikos

2017-07-13

Metal nanoclusters (M NCs ) based on silver and gold, abbreviated as Ag NCs and Au NCs , respectively, were synthesized and combined with functionalized graphene, abbreviated as f-G, forming novel M NC /f-G ensembles. The preparation of M NCs /f-G was achieved by employing attractive electrostatic interactions developed between negatively charged M NCs , attributed to the presence of carboxylates due to α-lipoic acid employed as a stabilizer, and positively charged f-G, attributed to the presence of ammonium units as addends. The realization of M NC /f-G ensembles was established via titration assays as evidenced by electronic absorption and photoluminescence spectroscopy as well as scanning transmission electron microscopy (STEM) and energy-dispersive X-ray (EDX) spectroscopy analyses. Photoinduced charge-transfer phenomena were inferred within M NCs /f-G, attributed to the suppression of M NC photoluminescence by the presence of f-G. Next, the M NC /f-G ensembles were successfully employed as proficient catalysts for the model reduction of 4-nitrophenol to the corresponding 4-aminophenol as proof for the photoinduced hydrogen production. Particularly, the reduction kinetics decelerated by half when bare M NCs were employed vs. the M NC /f-G ensembles, highlighting the beneficial role of M NCs /f-G in catalysing the process. Furthermore, Au NCs /f-G displayed exceptionally higher catalytic activity both in the dark and under visible light illumination conditions, which is ascribed to three synergistic mechanisms, namely, (a) hydride transfer from Au-H, (b) hydride transfer from photogenerated Au-H species, and (c) hydrogen produced by the photoreduction of water. Finally, recycling and re-employing M NCs /f-G in successive catalytic cycles without loss of activity toward the reduction of 4-nitrophenol was achieved, thereby highlighting their wider applicability.

Fabrication and characterization of MCC [Materials Characterization Center] approved testing material: ATM-10 glass

International Nuclear Information System (INIS)

Maupin, G.D.; Bowen, W.M.; Daniel, J.L.

1988-04-01

The Materials Characterization Center ATM-10 glass represents a reference commercial high-level waste form similar to that which will be produced by the West Valley Nuclear Service Co. Inc., West Valley, New York. The target composition and acceptable range of composition were defined by the sponsor, West Valley Nuclear Service. The ATM-10 glass was produced in accordance with the Pacific Northwest Laboratory QA Manual for License-Related Programs, MCC technical procedures, and MCC QA Plan that were in effect during the course of the work. The method and procedure to be used in the fabrication and characterization of the ATM-10 glass were specified in two run plans for glass preparation and a characterization plan. All of the ATM-10 glass was produced in the form of bars 1.9 /times/ 1.9 /times/ 10 cm nominal size, and 93 g nominal mass. A total of 15 bars of ATM-10 glass weighing 1394 g was produced. The production bars were characterized to determine the mean composition, oxidation state, and microstructure of the ATM-10 product. Table A summarizes the characterization results. The ATM-10 glass meets all specifications. The elemental composition and oxidation state of the glass are within the specifications of the client. Visually, the ATM-10 glass bars appear uniformly glassy and generally without exterior features. Microscopic examination revealed low (less than 2 wt %) concentractions of 3-μm iron-chrome (suspected spinel) crystals and /approximately/0.5-μm ruthenium inclusions scattered randomly throughout the glassy matrix. Closed porosity, with pores ranging in diameter from 5 to 250 μm, was observed in all samples. 4 refs., 10 figs., 21 tabs

Copper nanocluster coupling europium as an off-to-on fluorescence probe for the determination of phosphate ion in water samples.

Science.gov (United States)

Cao, Haiyan; Chen, Zhaohui; Huang, Yuming

2015-10-01

This paper reports an "off-to-on" fluorescence (FL) probe for sensitively and selectively detecting phosphate ions (Pi's). Fabrication of the probe was based on the competition between Pi's and tannic acid-stabilized copper nanoclusters (TA-Cu NCs) for Eu(3+) binding. The addition of Eu(3+) ions to TA-Cu NCs triggered the aggregation of TA-Cu NCs, which quenched the FL of TA-Cu NCs. After Pi addition, the aggregated TA-Cu NCs solubilized into the aqueous solution to facilitate the Pi-triggered dispersion of TA-Cu NCs. This phenomenon was due to the stronger binding ability between Pi's and Eu(3+) than that between TA and Eu(3+), leading to FL recovery of Cu NCs. The degree of redispersion of TA-Cu NCs was directly related to Pi concentration. Thus, Pi concentration can be quantitatively determined by the change in FL of the TA-Cu NCs dispersion. Under the optimized conditions, the change in FL presented a linear relationship with Pi concentration from 0.07 μmol L(-1) to 80 μmol L(-1). The limit of detection for Pi was 9.6×10(-3) μmol L(-1) at a signal-to-noise ratio of 3. For Pi determination in real samples, only 1 mL water sample was needed. The proposed probe was highly sensitive, free from the interference of other common species in aqueous media, and particularly useful for the fast and simple diagnosis of water-eutrophication extent. Copyright © 2015 Elsevier B.V. All rights reserved.

Uptake and effect of highly fluorescent silver nanoclusters on Scenedesmus obliquus.

Science.gov (United States)

Zhang, Li; He, Yiliang; Goswami, Nirmal; Xie, Jianping; Zhang, Bo; Tao, Xianji

2016-06-01

The release of silver nanoparticles (Ag NPs) in aquatic environment has caused wide public concern about their effects on living organisms (e.g., algae). However, how these small NPs exert cytotoxicity in the living organisms has always been under heated debate. In this study, the uptake and toxicity effects of strongly red-emitting fluorescent silver nanoclusters (r-Ag NCs) exposed to the green algae Scenedesmus obliquus was investigated. Upon exposure to pure r-Ag NCs and r-Ag NCs containing l-cysteine, the algae growth inhibition test showed that Ag(+) ions released from r-Ag NCs played an important role in the toxicity of r-Ag NCs along with the toxicity of intact r-Ag NCs. Furthermore, no signals of intracellular reactive oxygen species (ROS) were observed indicating that r-Ag NCs or released Ag(+) ions - mediated growth inhibition of algae cells was independent of ROS production. Transmission electron microscopy (TEM) and laser scanning confocal microscopy (LSCM) were employed to study cellular uptake and cytotoxicity. Furthermore, analysis of differential expressed gene demonstrated that r-Ag NCs as well as the released Ag(+) ions can simultaneously exist inside the algae cells, and inhibit the transcriptomic process of genes by their "joint-toxicity" mechanism. Taken together, our study provides a new insight into the molecular mechanisms of r-Ag NCs and Ag(+) ions exposure to the aquatic organism and can be applied to early diagnosis of ecologic risk mediated by others metal-based NPs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ligand induced shape transformation of thorium dioxide nanocrystals.

Science.gov (United States)

Wang, Gaoxue; Batista, Enrique R; Yang, Ping

2018-04-27

Nanocrystals (NCs) with size and shape dependent properties are a thriving research field. Remarkable progress has been made in the controlled synthesis of NCs of stable elements in the past two decades; however, the knowledge of the NCs of actinide compounds has been considerably limited due the difficulties in handling them both experimentally and theoretically. Actinide compounds, especially actinide oxides, play a critical role in many stages of the nuclear fuel cycle. Recently, a non-aqueous surfactant assisted approach has been developed for the synthesis of actinide oxide NCs with different morphologies, but an understanding of its control factors is still missing to date. Herein we present a comprehensive study on the low index surfaces of thorium dioxide (ThO2) and their interactions with relevant surfactant ligands using density functional calculations. A systematic picture on the thermodynamic stability of ThO2 NCs of different sizes and shapes is obtained employing empirical models based on the calculated surface energies. It is found that bare ThO2 NCs prefer the octahedral shape terminated by (111) surfaces. Oleic acid displays selective adsorption on the (110) surface, leading to the shape transformation from octahedrons to nanorods. Other ligands such as acetylacetone, oleylamine, and trioctylphosphine oxide do not modify the equilibrium shape of ThO2 NCs. This work provides atomic level insights into the anisotropic growth of ThO2 NCs that was recently observed in experiments, and thus may contribute to the controlled synthesis of actinide oxide NCs with well-defined size and shape for future applications.

Strategies for service-learning assessment in dental hygiene education.

Science.gov (United States)

Burch, Sharlee

2013-10-01

A large body of literature exists on the instructional pedagogy known as service-learning. Service-learning is a teaching and learning approach characterized by the dental hygiene student's practical application of academic studies and occurs within a community setting, to the benefit of both the student and community. Dental hygiene educators use service-learning to enhance student knowledge and application of oral health curriculum. This manuscript reports on the importance of service-learning assessment to the National Dental Hygiene Research Agenda as well as the future of the profession of dental hygiene and the successful strategies in service-learning evaluation available for utilization by dental hygiene educators.

The National Children's Study: a golden opportunity to advance the health of pregnant women.

Science.gov (United States)

Lyerly, Anne Drapkin; Little, Margaret Olivia; Faden, Ruth R

2009-10-01

With a $3 billion investment by the federal government, the National Children's Study (NCS) recently began recruitment. The NCS is a golden-and potentially missed-opportunity to study one of the most underrepresented populations in clinical research: pregnant women. As the nation's largest-ever study of children's health, the NCS will examine the effects of the environment on children from before birth to 21 years of age, with participants sampled primarily through women during pregnancy. Thus the NCS presents a rare opportunity to study the health of women during and after pregnancy, in addition to the health of their children. On both moral and policy grounds, we make the case for inclusion of women's health outcomes in the NCS.

Luminescent Organometallic Nanomaterials with Aggregation-Induced Emission.

Science.gov (United States)

Shu, Tong; Wang, Jianxing; Su, Lei; Zhang, Xueji

2018-07-04

Recent researches in metal nanoclusters (NCs) have prompted their promising practical applications in biomedical fields as novel inorganic luminophores. More recently, to further improve the photoluminescence (PL) performance of NCs, the aggregation-induced emission (AIE) effect has been introduced to develop highly luminescent metal NCs and metal complex materials. In this review, we start our discussion from recent progresses on AIE materials developments. Then, we address our understandings on the PL properties of thiolated metal NCs. Subsequently, we link thiolated metal NCs with AIE effect. We also highlight some recent advances in synthesizing the AIE-type metal complex nanomaterials. We finally discuss visions and directions for future development of AIE-type metal complex nanomaterials.

Increased osmolarity and cell clustering preserve canine notochordal cell phenotype in culture

NARCIS (Netherlands)

Spillekom, S.; Smolders, L.A.; Grinwis, G.C.M.; Arkesteijn, I.T.M.; Ito, K.; Meij, B.P.; Tryfonidou, M.A.

2014-01-01

Degeneration of the intervertebral disc (IVD) is associated with a loss of notochordal cells (NCs) from the nucleus pulposus (NP) and their replacement by chondrocyte-like cells. NCs are known to maintain extracellular matrix quality and stimulate the chondrocyte-like NP cells, making NCs attractive

Fabrication of transferrin functionalized gold nanoclusters/graphene oxide nanocomposite for turn-on near-infrared fluorescent bioimaging of cancer cells and small animals.

Science.gov (United States)

Wang, Yong; Chen, Jia-Tong; Yan, Xiu-Ping

2013-02-19

Transferrin (Tf)-functionalized gold nanoclusters (Tf-AuNCs)/graphene oxide (GO) nanocomposite (Tf-AuNCs/GO) was fabricated as a turn-on near-infrared (NIR) fluorescent probe for bioimaging cancer cells and small animals. A one-step approach was developed to prepare Tf-AuNCs via a biomineralization process with Tf as the template. Tf acted not only as a stabilizer and a reducer but also as a functional ligand for targeting the transferrin receptor (TfR). The prepared Tf-AuNCs gave intense NIR fluorescence that can avoid interference from biological media such as tissue autofluorescence and scattering light. The assembly of Tf-AuNCs and GO gave the Tf-AuNCs/GO nanocomposite, a turn-on NIR fluorescent probe with negligible background fluorescence due to the super fluorescence quenching property of GO. The NIR fluorescence of the Tf-AuNCs/GO nanocomposite was effectively restored in the presence of TfR, due to the specific interaction between Tf and TfR and the competition of TfR with the GO for the Tf in Tf-AuNCs/GO composite. The developed turn-on NIR fluorescence probe offered excellent water solubility, stability, and biocompatibility, and exhibited high specificity to TfR with negligible cytotoxicity. The probe was successfully applied for turn-on fluorescent bioimaging of cancer cells and small animals.

Engineering ultrasmall water-soluble gold and silver nanoclusters for biomedical applications.

Science.gov (United States)

Luo, Zhentao; Zheng, Kaiyuan; Xie, Jianping

2014-05-25

Gold and silver nanoclusters or Au/Ag NCs with core sizes smaller than 2 nm have been an attractive frontier of nanoparticle research because of their unique physicochemical properties such as well-defined molecular structure, discrete electronic transitions, quantized charging, and strong luminescence. As a result of these unique properties, ultrasmall size, and good biocompatibility, Au/Ag NCs have great potential for a variety of biomedical applications, such as bioimaging, biosensing, antimicrobial agents, and cancer therapy. In this feature article, we will first discuss some critical biological considerations, such as biocompatibility and renal clearance, of Au/Ag NCs that are applied for biomedical applications, leading to some design criteria for functional Au/Ag NCs in the biological settings. According to these biological considerations, we will then survey some efficient synthetic strategies for the preparation of protein- and peptide-protected Au/Ag NCs with an emphasis on our recent contributions in this fast-growing field. In the last part, we will highlight some potential biomedical applications of these protein- and peptide-protected Au/Ag NCs. It is believed that with continued efforts to understand the interactions of biomolecule-protected Au/Ag NCs with the biological systems, scientists can largely realize the great potential of Au/Ag NCs for biomedical applications, which could finally pave their way towards clinical use.

Third-order optical nonlinearity of N-doped graphene oxide nanocomposites at different GO ratios

Science.gov (United States)

Kimiagar, Salimeh; Abrinaei, Fahimeh

2018-05-01

In the present work, the influence of GO ratios on the structural, linear and nonlinear optical properties of nitrogen-doped graphene oxide nanocomposites (N-GO NCs) has been studied. N-GO NCs were synthesized by hydrothermal method. The XRD, FTIR, SEM, and TEM results confirmed the reduction of GO by nitrogen doping. The energy band gaps of N-GO NCs calculated from UV-Vis analyzed by using Tauc plot. To obtain further insight into potential optical changes in the N-GO NCs by increasing GO contents, Z-scan analysis was performed with nanosecond Nd-YAG laser at 532 nm. The nonlinear absorption coefficient, β, and nonlinear refractive index, n2, for N-GO NCs at the laser intensity of 113 MW/cm were measured and an increase was observed in both parameters after addition of nitrogen to GO. The third-order nonlinear optical susceptibilities of N-GO NCs were measured in the order of 10-9 esu. The results showed that N-GO NCs have negative nonlinearity which can be controlled by GO contents to obtain the highest values for nonlinear optical parameters. The nonlinear optical results not only imply that N-GO NCs can serve as an important material in the advancing of optoelectronics but also open new possibilities for the design of new graphene-based materials by variation of N and GO ratios as well as manufacturing conditions.

Evolvement of nuclear criticality safety programs

International Nuclear Information System (INIS)

Ketzlach, N.

1992-01-01

Nuclear criticality safety (NCS) has developed from a discipline requiring the services of personnel with only a background in reactor physics to that involving reactor physics, process engineering, and design as well as administration of the program to ensure all its requirements are implemented. When Oak Ridge National Laboratory (ORNL) was designed and constructed, the physicists at Los Alamos National Laboratory (LANL) were performing the criticality analyses. A physicist who had no chemical process or engineering experience was brought in from LANL to determine whether the facility would be safe. It was only because of his understanding of the reactor physics principles, scientific intuition, and some luck that the design and construction of the facility led to a safe plant. It took a number of years of experience with facility operations and the dedication of personnel for NCS to reach its present status as a recognized discipline

Sensitive and selective turn off-on fluorescence detection of heparin based on the energy transfer platform using the BSA-stabilized Au nanoclusters/amino-functionalized graphene oxide hybrids.

Science.gov (United States)

Lan, Jing; Zou, Hong Yan; Wang, Qiang; Zeng, Ping; Li, Yuan Fang; Huang, Cheng Zhi

2016-12-01

An ultra-sensitive and selective turn off-on fluorescence detection of heparin based on the energy transfer in the BSA-stabilized gold nanoclusters/amino-functionalized graphene oxide (BSA-AuNCs/NH 2 -GO) hybrids was successfully realized. The BSA-AuNCs containing amounts of carboxyl groups could be absorbed on the surface of NH 2 -GO through the electrostatic interaction, which resulted in the fluorescence quenching of BSA-AuNCs with high efficiency. However, heparin, possessing high density of negative charge, could compete with BSA-AuNCs to bind NH 2 -GO and block the energy transfer from BSA-AuNCs to NH 2 -GO. The fluorescence recovery of BSA-AuNCs was closely related to the amount of heparin and there was a good linear relationship between fluorescence recovery of BSA-AuNCs and heparin over the range of 100ng/mL to 30μg/mL with a detection limit of 40ng/mL. What's more, the fluorescence assay was successfully applied for heparin sensing in human serums and intracellular imaging. Copyright © 2016 Elsevier B.V. All rights reserved.

One-step engineered self-assembly Co3O4 nanoparticles to nanocubes for supercapacitors

Science.gov (United States)

Nagajyothi, P. C.; Pandurangan, M.; Sreekanth, T. V. M.; Shim, Jaesool

2018-02-01

Tricobalt tetraoxide or cobalt oxide (Co3O4) nanocubes (NCs) were synthesized from the self-assemblies of Co3O4 nanoparticles (NPs) via a simple one-step hydrothermal method. X-ray diffraction analysis confirmed the cubic crystal structure of Co3O4 NCs. The surface properties were investigated by x-ray photoelectron spectroscopy, which suggests the co-existence of Co in +2 and +3 states. The self-assemblies of aggregation of NPs to NCs were inspected using scanning electron microscopy, which is supported by transmission electron microscopy. The electrochemical properties of Co3O4 NCs were carried out by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) curves and impedance analysis. The areal capacitance of 3.04 mF cm-2 was obtained at current density of 10 μA cm-2. The Co3O4 NCs electrode exhibits good long-cyclic stability with 92.1% capacitance retention over 3000 cycles. The CV, GCD and impedance curves of Co3O4 NCs were recorded after cyclic test, which are similar to the curves recorded before the test. Therefore, the Co3O4 NCs serves good candidate as positive electrode materials for asymmetric supercapacitors.

Autoclave and beta-amylolysis lead to reduced in vitro digestibility of starch.

Science.gov (United States)

Hickman, B Elliot; Janaswamy, Srinivas; Yao, Yuan

2009-08-12

In this study, a combination of autoclave and beta-amylolysis was used to modulate the digestibility of normal corn starch (NCS) and wheat starch (WS). The modification procedure comprised three cycles of autoclave at 35% moisture content and 121 degrees C, beta-amylolysis, and one additional cycle of autoclave. Starch materials were sampled at each stage and characterized. The fine structure of starch was determined using high-performance size-exclusion chromatography, the micromorphology of starch dispersion was imaged using cryo-SEM, the crystalline pattern was evaluated using wide-angle X-ray powder diffraction, and the digestibility was measured using Englyst assay. After beta-amylolysis, amylose was enriched (from 25.4 to 33.2% for NCS and from 27.5 to 32.8% for WS) and the branch density was increased (from 5.2 to 7.7% for NCS and from 5.3 to 7.9% for WS). Cryo-SEM images showed that the autoclave treatment led to the formation of a low-swelling, high-density gel network, whereas beta-amylolysis nearly demolished the network structure. The loss of A-type crystalline structure and the formation of B- and V-type structures resulted from autoclave, which suggests the formation of amylose-based ordered structure. Englyst assay indicated that, due to beta-amylolysis, the resistant starch (RS) content was increased to 30 from 11% of native NCS and to 23 from 9% of native WS. In contrast, autoclave showed only minor impact on RS levels. The increase of RS observed in this study is associated with enhanced branch density, which is different from the four types of RS commonly defined.

Facile solvothermal synthesis of monodisperse Pt2.6Co1 nanoflowers with enhanced electrocatalytic activity towards oxygen reduction and hydrogen evolution reactions

International Nuclear Information System (INIS)

Jiang, Liu-Ying; Lin, Xiao-Xiao; Wang, Ai-Jun; Yuan, Junhua; Feng, Jiu-Ju; Li, Xin-Sheng

2017-01-01

Highlights: • Uniform Pt 2.6 Co 1 nanoflowers were prepared by a simple solvothermal method. • Glucose and CTAC were used as the green reductant and structure director, respectively. • The architectures had the enlarged ECSA. • The architectures exhibited excellent catalytic performances for HER in acid and alkaline media. • The architectures showed highly catalytic performances for ORR in acid media. - Abstract: Herein, uniform Pt 2.6 Co 1 nanoflowers (NFs) were synthesized in oleylamine by a one-pot solvothermal method, using cetyltrimethylammonium chloride (CTAC) and glucose as the capping agent and green reducing agent. The samples were mainly characterized by transmission electron microscopy (TEM), high angle annular dark-field scanning TEM (HAADF-STEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The architectures had larger electrochemically active surface area (ECSA) of 23.84 m 2 g −1 Pt than Pt 1.2 Co 1 nanocrystals (NCs, 14.96 m 2 g −1 Pt ), Pt 3.7 Co 1 NCs (16.96 m 2 g −1 Pt ) and commercial Pt black (20.35 m 2 g −1 Pt ). And the as-obtained Pt 2.6 Co 1 catalyst displayed superior catalytic performance and better durability for hydrogen evolution reaction (HER) as compared to Pt 1.2 Co 1 NCs, Pt 3.7 Co 1 NCs, commercial 50% Pt/C and Pt black catalysts in acid and alkaline media. Meanwhile, the electrocatalytic performance of Pt 2.6 Co 1 NFs for oxygen reduction reaction (ORR) is better in acid media as compared with that in alkaline media. It indicates the great potential applications of the as-prepared catalyst in fuel cells.

Pulsed ion-beam assisted deposition of Ge nanocrystals on SiO2 for non-volatile memory device

International Nuclear Information System (INIS)

Stepina, N.P.; Dvurechenskii, A.V.; Armbrister, V.A.; Kirienko, V.V.; Novikov, P.L.; Kesler, V.G.; Gutakovskii, A.K.; Smagina, Z.V.; Spesivtzev, E.V.

2008-01-01

A floating gate memory structure, utilizing Ge nanocrystals (NCs) deposited on tunnel SiO 2 , have been fabricated using pulsed low energy ion-beam induced molecular-beam deposition (MBD) in ultra-high vacuum. The ion-beam action is shown to stimulate the nucleation of Ge NCs when being applied after thin Ge layer deposition. Growth conditions for independent change of NCs size and array density were established allowing to optimize the structure parameters required for memory device. Activation energy E = 0.25 eV was determined from the temperature dependence of NCs array density. Monte Carlo simulation has shown that the process, determining NCs array density, is the surface diffusion. Embedding of the crystalline Ge dots into silicon oxide was carried out by selective oxidation of Si(100)/SiO 2 /Ge(NCs)/poly-Si structure. MOS-capacitor obtained after oxidation showed a hysteresis in its C-V curves attributed to charge retention in the Ge dots

Pulsed ion-beam assisted deposition of Ge nanocrystals on SiO{sub 2} for non-volatile memory device

Energy Technology Data Exchange (ETDEWEB)

Stepina, N.P. [Institute of Semiconductor Physics, Lavrenteva 13, 630090 Novosibirsk (Russian Federation)], E-mail: nstepina@mail.ru; Dvurechenskii, A.V.; Armbrister, V.A.; Kirienko, V.V.; Novikov, P.L.; Kesler, V.G.; Gutakovskii, A.K.; Smagina, Z.V.; Spesivtzev, E.V. [Institute of Semiconductor Physics, Lavrenteva 13, 630090 Novosibirsk (Russian Federation)

2008-11-03

A floating gate memory structure, utilizing Ge nanocrystals (NCs) deposited on tunnel SiO{sub 2}, have been fabricated using pulsed low energy ion-beam induced molecular-beam deposition (MBD) in ultra-high vacuum. The ion-beam action is shown to stimulate the nucleation of Ge NCs when being applied after thin Ge layer deposition. Growth conditions for independent change of NCs size and array density were established allowing to optimize the structure parameters required for memory device. Activation energy E = 0.25 eV was determined from the temperature dependence of NCs array density. Monte Carlo simulation has shown that the process, determining NCs array density, is the surface diffusion. Embedding of the crystalline Ge dots into silicon oxide was carried out by selective oxidation of Si(100)/SiO{sub 2} /Ge(NCs)/poly-Si structure. MOS-capacitor obtained after oxidation showed a hysteresis in its C-V curves attributed to charge retention in the Ge dots.

Preparation of Au Nanoclusters-Modified Polylactic Acid Fiber with Bright Red Fluorescence and its Use as Sensing Probe.

Science.gov (United States)

Zhu, Wenli; Li, Huili; Wan, Ajun; Liu, Lanbo

2017-01-01

In present work, the Au nanoclusters-modified polylactic acid fiber (PLA-Au NCs) with bright red fluorescence were fabricated by the encapsulation of Au nanoclusters (Au NCs) in the PLA fiber treated with H 2 O 2 . The Au 25 nanoclusters stabilized by bovine serum albumin (BSA-Au NCs) were prepared via an improved "green" synthetic routine. With pretreatment of the PLA fiber in H 2 O 2 concentration of 12 and 18 %, the as-prepared PLA-Au NCs exhibited brighter red emission with a strong peak centered at ~640 nm than BSA-Au NCs. The fluorescence can be quenched by nitric oxide (NO). A good linear relationship between the relative fluorescence quenching intensity of the as-prepared PLA-Au NCs and the concentration of NO can be obtained in the range of 0.0732 to 0.7320 mM, and the detection limit was 0.0070 mM.

Synthesis of bimetallic Pt-Pd core-shell nanocrystals and their high electrocatalytic activity modulated by Pd shell thickness

Science.gov (United States)

Li, Yujing; Wang, Zhi Wei; Chiu, Chin-Yi; Ruan, Lingyan; Yang, Wenbing; Yang, Yang; Palmer, Richard E.; Huang, Yu

2012-01-01

Bimetallic Pt-Pd core-shell nanocrystals (NCs) are synthesized through a two-step process with controlled Pd thickness from sub-monolayer to multiple atomic layers. The oxygen reduction reaction (ORR) catalytic activity and methanol oxidation reactivity of the core-shell NCs for fuel cell applications in alkaline solution are systematically studied and compared based on different Pd thickness. It is found that the Pd shell helps to reduce the over-potential of ORR by up to 50mV when compared to commercial Pd black, while generating up to 3-fold higher kinetic current density. The carbon monoxide poisoning test shows that the bimetallic NCs are more resistant to the CO poisoning than Pt NCs and Pt black. It is also demonstrated that the bimetallic Pt-Pd core-shell NCs can enhance the current density of the methanol oxidation reaction, lowering the over-potential by 35 mV with respect to the Pt core NCs. Further investigation reveals that the Pd/Pt ratio of 1/3, which corresponds to nearly monolayer Pd deposition on Pt core NCs, gives the highest oxidation current density and lowest over-potential. This study shows for the first time the systematic investigation of effects of Pd atomic shells on Pt-Pd bimetallic nanocatalysts, providing valuable guidelines for designing high-performance catalysts for fuel cell applications.Bimetallic Pt-Pd core-shell nanocrystals (NCs) are synthesized through a two-step process with controlled Pd thickness from sub-monolayer to multiple atomic layers. The oxygen reduction reaction (ORR) catalytic activity and methanol oxidation reactivity of the core-shell NCs for fuel cell applications in alkaline solution are systematically studied and compared based on different Pd thickness. It is found that the Pd shell helps to reduce the over-potential of ORR by up to 50mV when compared to commercial Pd black, while generating up to 3-fold higher kinetic current density. The carbon monoxide poisoning test shows that the bimetallic NCs are more

Gas-phase synthesis of semiconductor nanocrystals and its applications

Science.gov (United States)

Mandal, Rajib

Luminescent nanomaterials is a newly emerging field that provides challenges not only to fundamental research but also to innovative technology in several areas such as electronics, photonics, nanotechnology, display, lighting, biomedical engineering and environmental control. These nanomaterials come in various forms, shapes and comprises of semiconductors, metals, oxides, and inorganic and organic polymers. Most importantly, these luminescent nanomaterials can have different properties owing to their size as compared to their bulk counterparts. Here we describe the use of plasmas in synthesis, modification, and deposition of semiconductor nanomaterials for luminescence applications. Nanocrystalline silicon is widely known as an efficient and tunable optical emitter and is attracting great interest for applications in several areas. To date, however, luminescent silicon nanocrystals (NCs) have been used exclusively in traditional rigid devices. For the field to advance towards new and versatile applications for nanocrystal-based devices, there is a need to investigate whether these NCs can be used in flexible and stretchable devices. We show how the optical and structural/morphological properties of plasma-synthesized silicon nanocrystals (Si NCs) change when they are deposited on stretchable substrates made of polydimethylsiloxane (PDMS). Synthesis of these NCs was performed in a nonthermal, low-pressure gas phase plasma reactor. To our knowledge, this is the first demonstration of direct deposition of NCs onto stretchable substrates. Additionally, in order to prevent oxidation and enhance the luminescence properties, a silicon nitride shell was grown around Si NCs. We have demonstrated surface nitridation of Si NCs in a single step process using non?thermal plasma in several schemes including a novel dual-plasma synthesis/shell growth process. These coated NCs exhibit SiNx shells with composition depending on process parameters. While measurements including

On Advertising Games and Spillover in Service Systems

Directory of Open Access Journals (Sweden)

Lei Xu

2013-01-01

Full Text Available Motivated by the industry cases, we model the advertising competition between the dominant service provider and small service providers in one service market, where the dominant service provider has a major market share and the other small service providers share the remainder of market equally. Based on this setting, we discuss three advertising game models, that is, cooperative game, Boxed Pig game, and Prisoner’s game, derive the conditions for different advertising games, and characterize their equilibria. To be specific, it is found that the advertising spillover and the number of the small service providers directly determines the advertising game equilibria, while other market parameters, to some extent, can affect the results of the advertising game equilibria. According to our theoretical findings, some management insights and suggestions are given from both the academic and practical perspectives.

NDE Studies on CRDMs Removed From Service

International Nuclear Information System (INIS)

Doctor, Steven R.; Cumblidge, Stephen E.; Schuster, George J.; Hockey, Ronald L.; Abrefah, John

2005-01-01

Studies being conducted at the Pacific Northwest National Laboratory (PNNL) in Richland, Washington are focused on assessing the effectiveness of NDE inspections of control rod drive mechanism (CRDM) nozzles and J-groove weldments. The primary objective of this work is to provide information to the United States Nuclear Regulatory Commission (US NRC) on the effectiveness of ultrasonic testing (UT) and eddy current testing (ET) as related to the in-service inspection of CRDM nozzles and J-groove weldments, and to enhance the knowledge base of primary water stress corrosion cracking (PWSCC) through destructive characterization of the CRDM assemblies. In describing two CRDM assemblies removed from service, decontaminated, and then used in a series of NDE measurements, this paper will address the following questions: (1) What did each technique detect?, (2) What did each technique miss?, (3) How accurately did each technique characterize the detected flaws? Two CRDM assemblies including the CRDM nozzle, the J-groove weld, buttering, and a portion of the ferritic head material were selected for this study. One contained suspected PWSCC, based on in-service inspection data; the other contained evidence suggesting through-wall leakage, but this was unconfirmed. The selected NDE measurements follow standard industry techniques for conducting in-service inspections of CRDM nozzles and the crown of the J-groove welds and buttering. In addition, laboratory based NDE methods will be employed to conduct inspections of the CRDM assemblies, with particular emphasis on inspecting the J-groove weld and buttering. This paper will also describe the NDE methods used and discuss the NDE results. Future work will involve using the results from these NDE studies to guide the development of a destructive characterization plan to reveal the crack morphology, to be compared with NDE responses

Direct versus ligand-exchange synthesis of [PtAg28(BDT)12(TPP)4]4− nanoclusters: effect of a single-atom dopant on the optoelectronic and chemical properties

KAUST Repository

Bootharaju, Megalamane Siddaramappa; Kozlov, Sergey M.; Cao, Zhen; Harb, Moussab; Parida, Manas R.; Hedhili, Mohamed N.; Mohammed, Omar F.; Bakr, Osman; Cavallo, Luigi; Basset, Jean-Marie

2017-01-01

to offer monodisperse doped NCs. For instance, the direct synthesis of PtAg28 NCs produces a mixture of [Ag29(BDT)12(TPP)4]3- and [PtAg28(BDT)12(TPP)4]4- NCs (TPP: triphenylphosphine; BDT: 1,3-benzenedithiolate). Here, we designed a ligand-exchange (LE

STATISTIC MODEL OF DYNAMIC DELAY AND DROPOUT ON CELLULAR DATA NETWORKED CONTROL SYSTEM

Directory of Open Access Journals (Sweden)

MUHAMMAD A. MURTI

2017-07-01

Full Text Available Delay and dropout are important parameters influence overall control performance in Networked Control System (NCS. The goal of this research is to find a model of delay and dropout of data communication link in the NCS. Experiments have been done in this research to a water level control of boiler tank as part of the NCS based on internet communication network using High Speed Packet Access (HSPA cellular technology. By this experiments have been obtained closed-loop system response as well as data delay and dropout of data packets. This research contributes on modeling of the NCS which is combination of controlled plant and data communication link. Another contribution is statistical model of delay and dropout on the NCS.

TRENDS IN CONTEMPORARY PORT SERVICES MARKETS

Directory of Open Access Journals (Sweden)

Hanna Klimek

2014-12-01

Full Text Available This article describes the issues associated with functioning of contemporary seaport services markets. The growth of international supply chains, technical progress and the integration processes in shipping, growth of containerization, increasing competition in the seaport services markets and environmental protection regulations make it necessary for port service providers to adapt to the changing expectations and requirements of their customers, both shippers and, especially maritime, carriers. Thus, the activities they undertake are associated with making investments to ensure an adequate capacity to handle cargo, passengers and means of transport, required quality of service, but also with appropriate organization of port supply centres and lead to an improvement of their competitiveness. Both the factors associated with the external and internal environment of seaports affect the changes in the relationship between the supply and demand on port services markets. Contemporary port services markets are characterized by certain phenomena which can be a sign of their adaptation and development. The aim of this article is to present the essence of the port services market and its relationship with the environment, which subject to rapid and significant changes, creates new conditions for the operation of port supply centres and the entire port services market.

Online MOS Capacitor Characterization in LabVIEW Environment

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Chinmay K Maiti

2009-08-01

Full Text Available We present an automated evaluation procedure to characterize MOS capacitors involving high-k gate dielectrics. Suitability of LabVIEW environment for online web-based semiconductor device characterization is demonstrated. Developed algorithms have been successfully applied to automate the MOS capacitor measurements for Capacitance-Voltage, Conductance-Voltage and Current-Voltage characteristics. Implementation of the algorithm for use as a remote internet-based characterization tool where the client and server communicate with each other via web services is also shown.

AVTA Federal Fleet PEV Readiness Data Logging and Characterization Study for the National Park Service: Golden Gate National Recreation Area

Energy Technology Data Exchange (ETDEWEB)

Stephen Schey; Jim Francfort

2014-03-01

Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy's Idaho National Laboratory, is the lead laboratory for U.S. Department of Energy Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (ITSNA) to collect data on federal fleet operations as part of the Advanced Vehicle Testing Activity's Federal Fleet Vehicle Data Logging and Characterization study. The Advanced Vehicle Testing Activity study seeks to collect data to validate the utilization of advanced electric drive vehicle transportation. This report focuses on the Golden Gate National Recreation Area (GGNRA) fleet to identify daily operational characteristics of select vehicles and report findings on vehicle and mission characterizations to support the successful introduction of plug-in electric vehicles (PEVs) into the agencies' fleets. Individual observations of these selected vehicles provide the basis for recommendations related to electric vehicle adoption and whether a battery electric vehicle or plug-in hybrid electric vehicle (PHEV) (collectively PEVs) can fulfill the mission requirements. GGNRA identified 182 vehicles in its fleet, which are under the management of the U.S. General Services Administration. Fleet vehicle mission categories are defined in Section 4, and while the GGNRA vehicles conduct many different missions, only two (i.e., support and law enforcement missions) were selected by agency management to be part of this fleet evaluation. The selected vehicles included sedans, trucks, and sport-utility vehicles. This report will show that battery electric vehicles and/or PHEVs are capable of performing the required missions and providing an alternative vehicle for support vehicles and PHEVs provide the same for law enforcement, because each has a sufficient range for individual trips and time is available each day for charging to accommodate multiple trips per day. These

Nurses assessing pain with the Nociception Coma Scale: interrater reliability and validity

NARCIS (Netherlands)

Vink, Peter; Eskes, Anne Maria; Lindeboom, Robert; van den Munckhof, Pepijn; Vermeulen, Hester

2014-01-01

The Nociception Coma Scale (NCS) is a pain observation tool, developed for patients with disorders of consciousness (DOC) due to acquired brain injury (ABI). The aim of this study was to assess the interrater reliability of the NCS and NCS-R among nurses for the assessment of pain in ABI patients

A facile method to prepare "green" nano-phosphors with a large Stokes-shift and solid-state enhanced photophysical properties based on surface-modified gold nanoclusters.

Science.gov (United States)

Cheng, C H; Huang, H Y; Talite, M J; Chou, W C; Yeh, J M; Yuan, C T

2017-12-15

Colloidal nano-materials, such as quantum dots (QDs) have been applied to light-conversion nano-phosphors due to their unique tunable emission. However, most of the QDs involve toxic elements and are synthesized in a hazardous solvent. In addition, conventional QD nano-phosphors with a small Stokes shift suffered from reabsorption losses and aggregation-induced quenching in the solid state. Here, we demonstrate a facile, matrix-free method to prepare eco-friendly nano-phosphors with a large Stokes shift based on aqueous thiolate-stabilized gold nanoclusters (GSH-AuNCs) with simple surface modifications. Our method is just to drop GSH-AuNCs solution on the aluminum foil and then surface-modified AuNCs (Al-GSH-AuNCs) can be spontaneously precipitated out of the aqueous solution. Compared with pristine GSH-AuNCs in solution, the Al-GSH-AuNCs exhibit enhanced solid-state PL quantum yields, lengthened PL lifetime, and spectral blue shift, which can be attributed to the aggregation-induced emission enhancement facilitated by surface modifications. Such surface-treatment induced aggregation of AuNCs can restrict the surface-ligand motion, leading to the enhancement of PL properties in the solid state. In addition, the Al-GSH-AuNCs nano-phosphors with a large Stokes shift can mitigate the aggregation-induced PL quenching and reabsorption losses, which would be potential candidates for "green" nano-phosphors. Copyright © 2017 Elsevier Inc. All rights reserved.

Too little, too late: comparison of nutritional status and quality of life of nutrition care and support recipient and non-recipients among HIV-positive adults in KwaZulu-Natal, South Africa.

Science.gov (United States)

Oketch, Jecinter Akinyi; Paterson, Marie; Maunder, Eleni Winfred; Rollins, Nigel Campbell

2011-03-01

Compare the nutritional vulnerability, risk of malnutrition, nutritional status and quality of life (QoL) between recipients and non-recipients of nutrition care and support (NCS) of HIV-positive adults. In 2009, a household-based cross-sectional study of HIV-positive adults, NCS recipients (n=97) and non-NCS recipients (n=203) from KwaZulu-Natal was conducted. Nutritional vulnerability (socio-economic status; food security; self-reported health status; nutritional knowledge and attitude), risk of malnutrition (nutrition assessment screening tool), anthropometry (body mass index; mid-upper arm circumference; waist-to-hip ratio) and QoL (general health; self-care; physical functioning) were compared between the two groups. Although the result suggests a modest impairment of QoL, NCS recipients were twice as likely to have severe impairment of general health; self-care functioning and QoL. Overweight and obesity were common despite indications of high prevalence of food insecurity, possible-risk of malnutrition and diets predominantly of cereals. NCS recipients were more frequently taking anti-retroviral drugs, receiving social grants, reporting good eating plans and owning kitchen gardens. Non-NCS recipients had been generally sick, reported fatigue, nausea, appetite loss and diarrhoea. NCS recipients were twice as likely to experience oral thrush. Contextual factors such as low dietary diversity and household food insecurity that exacerbates nutritional vulnerability and malnutrition should be considered when providing NCS to fully achieve nutritional recovery and QoL of HIV-positive adults. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement.

Science.gov (United States)

Greenberg, Benjamin L; Ganguly, Shreyashi; Held, Jacob T; Kramer, Nicolaas J; Mkhoyan, K Andre; Aydil, Eray S; Kortshagen, Uwe R

2015-12-09

Metal oxide semiconductor nanocrystals (NCs) exhibit localized surface plasmon resonances (LSPRs) tunable within the infrared (IR) region of the electromagnetic spectrum by vacancy or impurity doping. Although a variety of these NCs have been produced using colloidal synthesis methods, incorporation and activation of dopants in the liquid phase has often been challenging. Herein, using Al-doped ZnO (AZO) NCs as an example, we demonstrate the potential of nonthermal plasma synthesis as an alternative strategy for the production of doped metal oxide NCs. Exploiting unique, thoroughly nonequilibrium synthesis conditions, we obtain NCs in which dopants are not segregated to the NC surfaces and local doping levels are high near the NC centers. Thus, we achieve overall doping levels as high as 2 × 10(20) cm(-3) in NCs with diameters ranging from 12.6 to 3.6 nm, and for the first time experimentally demonstrate a clear quantum confinement blue shift of the LSPR energy in vacancy- and impurity-doped semiconductor NCs. We propose that doping of central cores and heavy doping of small NCs are achievable via nonthermal plasma synthesis, because chemical potential differences between dopant and host atoms-which hinder dopant incorporation in colloidal synthesis-are irrelevant when NC nucleation and growth proceed via irreversible interactions among highly reactive gas-phase ions and radicals and ligand-free NC surfaces. We explore how the distinctive nucleation and growth kinetics occurring in the plasma influences dopant distribution and activation, defect structure, and impurity phase formation.

Dioxouranium(VI) complexes with benzimidazole and benzoxazole derivatives

International Nuclear Information System (INIS)

Mansingh, P.S.; Dash, K.C.

1995-01-01

UO 2 LηX 2 [X = NO 3 ,NCS and 0.5 SO 4 and when n = 2, L = 2-(2-hydroxyphyenyl) benzimidazole (HPBI) or 2-(2-aminophenyl) benzimidazole(APBI) and for n=1, L = 2-(2-pyridyl) benzoxazole (PBO)] were synthesized and characterized by several physico chemical techniques including molar conductance data, IR, 1 H and 13 C NMR and thermogravimetric analysis. (author). 5 refs

The prevalence and correlates of lifetime psychiatric disorders and trauma exposures in urban and rural settings: results from the national comorbidity survey replication (NCS-R.

Directory of Open Access Journals (Sweden)

Jennifer S McCall-Hosenfeld

Full Text Available Distinctions between rural and urban environments produce different frequencies of traumatic exposures and psychiatric disorders. We examine the prevalence of psychiatric disorders and frequency of trauma exposures by position on the rural-urban continuum.The National Comorbidity Survey Replication (NCS-R was used to evaluate psychiatric disorders among a nationally-representative sample of the U.S. population. Rurality was designated using the Department of Agriculture's 2003 rural-urban continuum codes (RUCC, which differentiate counties into levels of rurality by population density and adjacency to metropolitan areas. Lifetime psychiatric disorders included post-traumatic stress disorder (PTSD, anxiety disorders, major depressive disorder, mood disorders, impulse-control disorders, and substance abuse. Trauma exposures were classified as war-related, accident-related, disaster-related, interpersonal or other. Weighted logistic regression models examined the odds of psychiatric disorders and trauma exposures by position on the rural-urban continuum, adjusted for relevant covariates.75% of participants were metropolitan, 12.2% were suburban, and 12.8% were from rural counties. The most common disorder reported was any anxiety disorder (38.5%. Drug abuse was more common among metropolitan (8.7%, p = 0.018, compared to nonmetropolitan (5.1% suburban, 6.1% rural participants. A one-category increase in rurality was associated with decreased odds for war-related trauma (aOR = 0.86, 95%CI 0.78-0.95. Rurality was not associated with risk for any other lifetime psychiatric disorders or trauma exposure.Contrary to the expectation of some rural primary care providers, the frequencies of most psychiatric disorders and trauma exposures are similar across the rural-urban continuum, reinforcing calls to improve mental healthcare access in resource-poor rural communities.

Desempenho diagnóstico e associações clínicas dos anticorpos contra componentes da cromatina no lúpus eritematoso sistêmico juvenil Diagnostic performance and clinical associations of antibodies to the chromatin antigenic system in juvenile systemic lupus erythematosus

Directory of Open Access Journals (Sweden)

Silene Peres Keusseyan

2012-10-01

Full Text Available OBJETIVOS: Determinar a frequência de anticorpos contra componentes da cromatina no lúpus eritematoso sistêmico juvenil (LESJ e correlacionar a presença desses autoanticorpos com manifestações clínicas e atividade da doença. MÉTODOS: Os anticorpos anticromatina (anti-CHR, antinucleossomo (anti-NCS e anti-dsDNA foram medidos em 175 indivíduos, incluindo 37 pacientes com LESJ ativo e 41 com doença inativa, 47 com doenças autoimunes não lúpicas, e 50 crianças saudáveis. Um teste ELISA in house foi desenvolvido com nucleossomos purificados a partir de timo de bezerro para determinar os anticorpos IgG e IgG3 anti-NCS. Anti-CHR e anti-dsDNA foram detectados por kits comerciais de ELISA (INOVA. RESULTADOS: Anticorpos anti-NCS e anti-CHR exibiram não só uma alta especificidade para LESJ, mas também uma frequência semelhante em LESJ ativo e inativo. Os níveis séricos de anti-CHR e IgG/IgG3 anti-NCS não diferiram entre LESJ ativo e inativo. Houve correlação entre o SLEDAI e os anticorpos anti-dsDNA, mas não com os anticorpos contra outros componentes da cromatina. Houve associação de anticorpos anti-dsDNA, anti-CHR e IgG/IgG3 anti-NCS com proteinúria e baixos níveis séricos de C4. Foram observados anticorpos anti-NCS em 14% dos pacientes com LESJ na ausência de anticorpos anti-dsDNA. CONCLUSÕES: Nossos dados indicam que os anticorpos anti-NCS e anti-CHR são marcadores diagnósticos relevantes para LESJ e parecem estar correlacionados com a atividade da nefrite lúpica no LESJ. O anticorpo IgG3 anti-NCS não parece ser mais relevante como marcador de atividade da doença ou nefrite ativa no LESJ em comparação ao anticorpo IgG anti-NCS.OBJECTIVES: To determine the frequency of antibodies to chromatin components in juvenile systemic lupus erythematosus (JSLE, and to correlate the presence of these autoantibodies with clinical manifestations and disease activity. METHODS: Anti-chromatin (anti-CHR, anti-nucleosome core

Development and evaluation of targeting ligands surface modified paclitaxel nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Sohn, Jeong Sun [Division of Undeclared Majors, Chosun University, Gwangju 501-759 (Korea, Republic of); Yoon, Doo-Soo; Sohn, Jun Youn [Department of Bioenvironmental & Chemical Engineering, Chosun College of Science & Technology, Gwangju 501-744 (Korea, Republic of); Park, Jeong-Sook, E-mail: eicosa@cnu.ac.kr [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Choi, Jin-Seok, E-mail: c34281@gmail.com [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of)

2017-03-01

To overcome the toxicity of excipient or blank nanoparticles for drug delivery nano-system, the surface modified paclitaxel nanocrystals (PTX-NC) have been developed. PTX-NCs were prepared by nano-precipitation method. The surface of PTX-NCs were modified by grafting with apo-transferrin (Tf) or hyaluronic acid (HA). The physical properties of PTX-NCs were evaluated by field emission scanning electron microscope (FE-SEM), zeta-sizer, zeta-potential, differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectrometry. In vitro drug release study was performed in phosphate buffered saline (PBS) with or without 0.5% (w/v) Tween 80 for 24 h. Cellular uptake was studied at time intervals of 0.5, 1, and 2 h in MCF-7 cells, and cell growth inhibition study was performed for 24 h using MCF-7 cells (cancer cells), and HaCaT cells (normal cells). Three different types of PTX-NCs with a mean size of 236.0 ± 100.6 nm (PTX-NC), 302.0 ± 152.0 nm (Tf-PTX-NC) and 339 ± 180.6 nm (HA-PTX-NC) were successfully prepared. The drug release profiles showed 29.1%/6.9% (PTX (pure)), 40.7%/23.9% (PTX-NC), 50.5%/25.1% (Tf-PTX-NC) and 46.8/24.8% (HA-PTX-NC) in PBS with/without 0.5% (w/v) Tween 80 for 24 h, respectively. As per the results, the drug release of PTX-NCs showed the faster release as compared to that of PTX (pure). Surface modified PTX-NCs exhibited higher values for cell permeability than unmodified PTX-NC in the cellular uptake study. Surface modified PTX-NCs inhibited the cell growth approximately to 60% in MCF-7 cells, however effect of surface modified PTX-NCs on normal cell line was lower than the PTX-NC and PTX (pure). In conclusion, biological macromolecules (Tf or HA) surface modified PTX-NC enhanced the cellular uptake and the cell growth inhibition. - Highlights: • Surface modified PTX-NCs with HA and Tf are successfully prepared by adsorption method. • Enhanced cellular uptake of modified PTX-NCs compared to unmodified PTX-NC • Improved

Oral administration of iron-saturated bovine lactoferrin–loaded ceramic nanocapsules for breast cancer therapy and influence on iron and calcium metabolism

Directory of Open Access Journals (Sweden)

Mahidhara G

2015-06-01

Full Text Available Ganesh Mahidhara, Rupinder K Kanwar, Kislay Roy, Jagat R Kanwar Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research, School of Medicine, Molecular and Medical Research Strategic Research Centre, Faculty of Health, Deakin University, Waurn Ponds, VIC, Australia Abstract: We determined the anticancer efficacy and internalization mechanism of our polymeric–ceramic nanoparticle system (calcium phosphate nanocores, enclosed in biodegradable polymers chitosan and alginate nanocapsules/nanocarriers [ACSC NCs] loaded with iron-saturated bovine lactoferrin (Fe-bLf in a breast cancer xenograft model. ACSC-Fe-bLf NCs with an overall size of 322±27.2 nm were synthesized. In vitro internalization and anticancer efficacy were evaluated in the MDA-MB-231 cells using multicellular tumor spheroids, CyQUANT and MTT assays. These NCs were orally delivered in a breast cancer xenograft mice model, and their internalization, cytotoxicity, biodistribution, and anticancer efficacy were evaluated. Chitosan-coated calcium phosphate Fe-bLf NCs effectively (59%, P≤0.005 internalized in a 1-hour period using clathrin-mediated endocytosis (P≤0.05 and energy-mediated pathways (P≤0.05 for internalization; 3.3 mg/mL of ACSC-Fe-bLf NCs completely disintegrated (~130-fold reduction, P≤0.0005 the tumor spheroids in 72 hours and 96 hours. The IC50 values determined for ACSC-Fe-bLf NCs were 1.69 mg/mL at 10 hours and 1.62 mg/mL after 20 hours. We found that Fe-bLf-NCs effectively (P≤0.05 decreased the tumor size (4.8-fold compared to the void NCs diet and prevented tumor recurrence when compared to intraperitoneal injection of Taxol and Doxorubicin. Receptor gene expression and micro-RNA analysis confirmed upregulation of low-density lipoprotein receptor and transferrin receptor (liver, intestine, and brain. Several micro-RNAs responsible for iron metabolism upregulated with NCs were identified. Taken together, orally delivered Fe-bLf NCs

Surfaces of nanomaterials for sustainable energy applications: thin-film 2D-ACAR and PALS studies

Science.gov (United States)

Barbiellini, B.; Chai, L.; Al-Sawai, W.; Eijt, S. W. H.; Mijnarends, P. E.; Schut, H.; Gao, Y.; Houtepen, A. J.; Ravelli, L.; Egger, W.; van Huis, M. A.; Bansil, A.

2013-03-01

Positron (e+) annihilation spectroscopy is one of only a few techniques to probe the surfaces of nanoparticles. We investigated thin films of PbSe colloidal semiconductor nanocrystals (NCs) in the range 2-10 nm as prospective highly efficient absorbers for solar cells. We compare and contrast our findings with previous studies on CdSe NCs. Evidence obtained from our e+ lifetime spectroscopy study using the PLEPS spectrometer shows that 90-95% of the implanted positrons are effectively trapped and confined at the surfaces of these NCs. The remaining 5-10% of the e+ annihilate in the relatively large oleic acid ligands, in fair agreement with the estimated positron stopping power of the PbSe nanoparticle ``core'' relative to the ligand ``shell.'' 2D-ACAR measurements on the same set of films using the low-energy e+ beam POSH showed that the e+ wavefunction at the surfaces of the PbSe NCs is more localized than for the case of CdSe NCs. Comparison with calculated e+ - e- momentum densities indicates a Pb deficiency at the surfaces of the PbSe NCs, which correlates with e+ lifetime and the NCs morphology. Work supported in part by the US Department of Energy.

A simple route for making surfactant free lead sulfide (PbS) quantum dots

Energy Technology Data Exchange (ETDEWEB)

Alam, Firoz; Kumar, Neetesh; Dutta, Viresh, E-mail: vdutta@ces.iitd.ac.in

2015-05-15

Highlights: • Surfactant free PbS NCs were successfully synthesised using CoSP technique. • The technique eliminates the requirements of washing to remove the ligands. • Grinding using mortar and pestle creates well separated PbS QDs. • Surfactant free PbS NCs are stable and do not show any degradation with time. - Abstract: An efficient, cost effective and less time consuming method suitable for mass production of surfactant free quantum dots (QDs) of lead sulfide (PbS) is reported. PbS nanocrystals (NCs) are first synthesised by continuous spray pyrolysis (CoSP) technique and de-agglomeration into PbS quantum dots (QDs) is achieved by vigorous mechanical grinding using mortar and pestle. Lead acetate and thiourea were used as the precursor materials for preparation of surfactant free PbS NCs. The broadening in XRD peaks of ground NCs as compared to as synthesized PbS NCs clearly indicated the reduction in particle size to be QDs of PbS. The TEM images also showed that ground PbS NCs were nearly spherical in shape having an average diameter in the range of 4–6 nm. The shift in optical gap from 0.41 eV to 1.47 eV supported the QD formation.

Magnetically addressable fluorescent Fe3O4/ZnO nanocomposites: Structural, optical and magnetization studies

Science.gov (United States)

Roychowdhury, A.; Pati, S. P.; Mishra, A. K.; Kumar, S.; Das, D.

2013-06-01

Fe3O4/ZnO nanocomposites (NCs) are prepared by a wet chemical route. X-ray diffraction, transmission electron microscopy and Fourier transform infrared spectroscopy studies confirm the coexistence of Fe3O4 and ZnO phases in the NCs. The UV-vis absorption spectra show a red shift of the absorption peak with increase in Fe3O4 content indicating a modification of the band structure of ZnO in the NCs. Photoluminescence emission spectra of the NCs display strong excitonic emission in the UV region along with weak emission bands in the visible range caused by electronic transitions involving defect-related energy levels in the band gap of ZnO. Positron annihilation lifetimes indicate that cation vacancies in the ZnO structure are the strong traps for positrons and the overall defect concentration in the NCs decreases with increase in Fe3O4 content. Dc magnetization measurements reveal an anomalous temperature dependence of the coercivity of the NCs that is argued to be due to the anomalous variation of magnetocrystalline anisotropy at lower temperature. The irreversibility observed in the temperature dependent ZFC-FC magnetization points to the presence of a spin-glass phase in the NCs.

Enhancing Hydrogen Diffusion in Silica Matrix by Using Metal Ion Implantation to Improve the Emission Properties of Silicon Nanocrystals

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J. Bornacelli

2014-01-01

Full Text Available Efficient silicon-based light emitters continue to be a challenge. A great effort has been made in photonics to modify silicon in order to enhance its light emission properties. In this aspect silicon nanocrystals (Si-NCs have become the main building block of silicon photonic (modulators, waveguide, source, and detectors. In this work, we present an approach based on implantation of Ag (or Au ions and a proper thermal annealing in order to improve the photoluminescence (PL emission of Si-NCs embedded in SiO2. The Si-NCs are obtained by ion implantation at MeV energy and nucleated at high depth into the silica matrix (1-2 μm under surface. Once Si-NCs are formed inside the SiO2 we implant metal ions at energies that do not damage the Si-NCs. We have observed by, PL and time-resolved PL, that ion metal implantation and a subsequent thermal annealing in a hydrogen-containing atmosphere could significantly increase the emission properties of Si-NCs. Elastic Recoil Detection measurements show that the samples with an enhanced luminescence emission present a higher hydrogen concentration. This suggests that ion metal implantation enhances the hydrogen diffusion into silica matrix allowing a better passivation of surface defects on Si NCs.

Nonenzymatic sensing of glucose at neutral pH values using a glassy carbon electrode modified with graphene nanosheets and Pt-Pd bimetallic nanocubes

International Nuclear Information System (INIS)

Chen, Xiaomei; Tian, Xiaotian; Zhao, Limin; Huang, Zhiyong; Oyama, Munetaka

2014-01-01

We report on a nonenzymatic method for the determination of glucose using an electrode covered with graphene nanosheets (GNs) modified with Pt-Pd nanocubes (PtPdNCs). The latter were prepared on GNs by using N,N-dimethylformamide as a bifunctional solvent for the reduction of both metallic precursors and graphene oxide, and for confining the growth of PtPdNCs on the surface. The modified electrode displays strong and sensitive current response to the electrooxidation of glucose, notably at pH 7. The sensitivities increase in the order of Pt 1 Pd 5 NCs< Pt 1 Pd 3 NCs< Pt 5 Pd 1 NCs< Pt 3 Pd 1 NCs< Pt 1 Pd 1 NCs. At an applied potential of +0.25 V, the electrode responds linearly (R = 0.9987) to glucose in up to 24.5 mM concentration, with a sensitivity of 1.4 μA cm −2 M −1 . The sensor is not poisoned by chloride, and not interfered by ascorbic acid, uric acid and p-acetamidophenol under normal physiological conditions. The modified electrode also displays a wide linear range, good stability and fast amperometric response, thereby indicating the potential of the bimetallic materials for nonenzymatic sensing of glucose. (author)

Sensitive detection of mercury and copper ions by fluorescent DNA/Ag nanoclusters in guanine-rich DNA hybridization.

Science.gov (United States)

Peng, Jun; Ling, Jian; Zhang, Xiu-Qing; Bai, Hui-Ping; Zheng, Liyan; Cao, Qiu-E; Ding, Zhong-Tao

2015-02-25

In this work, we designed a new fluorescent oligonucleotides-stabilized silver nanoclusters (DNA/AgNCs) probe for sensitive detection of mercury and copper ions. This probe contains two tailored DNA sequence. One is a signal probe contains a cytosine-rich sequence template for AgNCs synthesis and link sequence at both ends. The other is a guanine-rich sequence for signal enhancement and link sequence complementary to the link sequence of the signal probe. After hybridization, the fluorescence of hybridized double-strand DNA/AgNCs is 200-fold enhanced based on the fluorescence enhancement effect of DNA/AgNCs in proximity of guanine-rich DNA sequence. The double-strand DNA/AgNCs probe is brighter and stable than that of single-strand DNA/AgNCs, and more importantly, can be used as novel fluorescent probes for detecting mercury and copper ions. Mercury and copper ions in the range of 6.0-160.0 and 6-240 nM, can be linearly detected with the detection limits of 2.1 and 3.4 nM, respectively. Our results indicated that the analytical parameters of the method for mercury and copper ions detection are much better than which using a single-strand DNA/AgNCs. Copyright © 2014 Elsevier B.V. All rights reserved.

Copper nanoclusters as probes for turn-on fluorescence sensing of L-lysine.

Science.gov (United States)

Zhang, Mingming; Qiao, Juan; Zhang, Shufeng; Qi, Li

2018-05-15

Herein, a unique protocol based on copper nanoclusters (CuNCs) probe for turn-on fluorescence sensing of L-lysine was developed. The fluorescent CuNCs with ovalbumin as the stabilizer was prepared by a simple, one-step and green method. When 370 nm was used as the excitation wavelength, the resultant CuNCs exhibited a pale blue fluorescence with the maximum emission at 440 nm. Interestingly, existence of L-lysine evoked the obvious fluorescence intensity increase of CuNCs. The detection limit of the proposed method for L-lysine was 5.5 μM, with a good linear range from 10.0 μM to 1.0 mM (r 2 = 0.999). Moreover, the possible mechanism for enhanced fluorescence intensity of CuNCs by addition of L-lysine was explored and discussed briefly. Further, the as-prepared fluorescent CuNCs was successfully applied in detection of L-lysine in urine. Our results demonstrated that L-lysine could be monitored by the probe, providing new path for construction of CuNCs as fluorescent probes and showing great potential in quantification of L-lysine in real samples. Copyright © 2018 Elsevier B.V. All rights reserved.

RA radiological characterization database application

International Nuclear Information System (INIS)

Steljic, M.M; Ljubenov, V.Lj. . E-mail address of corresponding author: milijanas@vin.bg.ac.yu; Steljic, M.M.)

2005-01-01

Radiological characterization of the RA research reactor is one of the main activities in the first two years of the reactor decommissioning project. The raw characterization data from direct measurements or laboratory analyses (defined within the existing sampling and measurement programme) have to be interpreted, organized and summarized in order to prepare the final characterization survey report. This report should be made so that the radiological condition of the entire site is completely and accurately shown with the radiological condition of the components clearly depicted. This paper presents an electronic database application, designed as a serviceable and efficient tool for characterization data storage, review and analysis, as well as for the reports generation. Relational database model was designed and the application is made by using Microsoft Access 2002 (SP1), a 32-bit RDBMS for the desktop and client/server database applications that run under Windows XP. (author)

Reinforcement Learning Based Web Service Compositions for Mobile Business

Science.gov (United States)

Zhou, Juan; Chen, Shouming

In this paper, we propose a new solution to Reactive Web Service Composition, via molding with Reinforcement Learning, and introducing modified (alterable) QoS variables into the model as elements in the Markov Decision Process tuple. Moreover, we give an example of Reactive-WSC-based mobile banking, to demonstrate the intrinsic capability of the solution in question of obtaining the optimized service composition, characterized by (alterable) target QoS variable sets with optimized values. Consequently, we come to the conclusion that the solution has decent potentials in boosting customer experiences and qualities of services in Web Services, and those in applications in the whole electronic commerce and business sector.

Migration of CrSi2 nanocrystals through nanopipes in the silicon cap

International Nuclear Information System (INIS)

Galkin, N.G.; Dozsa, L.; Chusovitin, E.A.; Pecz, B.; Dobos, L.

2010-01-01

CrSi 2 nanocrystals (NC) were grown by reactive deposition epitaxy of Cr at 550 deg. C. After deposition the Cr is localized in about 20-30 nm dots on the Si surface. The NCs were covered by silicon cap grown by molecular beam epitaxy at 700 deg. C. The redistribution of NCs in the silicon cap was investigated by transmission electron microscopy and atomic force microscopy. The NCs are partly localized at the deposition depth, and partly migrate near the surface. A new migration mechanism of the CrSi 2 NCs is observed, they are transferred from the bulk toward the surface through nanopipes formed in the silicon cap. The redistribution of CrSi 2 NCs strongly depends on Cr deposition rate and on the cap growth temperature.

Aqueous Synthesis of ZnSe/ZnS-2-R-Benzothiazole Nanocrystals with White Emission

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Ying-Fan Liu

2016-01-01

Full Text Available We prepared water-soluble white light-emitting ZnSe/ZnS-2-R-benzothiazole nanocrystals (NCs, R = 2-hydroxy-5-(2,5-dimethyl-thienyl-phenyl. The penicillamine (Pen capped ZnSe/ZnS NCs were firstly prepared with high photoluminescence quantum yields (PL QY of 40%. Then they bond to 2-R-benzothiazole molecules, resulting in white light-emitting ZnSe/ZnS-2-R-benzothiazole NCs with QY of 75% over a 375 to 650 nm range of emission, which can be applied to white light-emitting diodes. The ZnSe/ZnS-2-R-benzothiazole NCs with two emission bands at around 451 and 557 nm were discussed and the possible mechanism of the interaction of ZnSe/ZnS NCs with 2-R-benzothiazole was also proposed.

The nucleobase cation symporter 1 of Chlamydomonas reinhardtii and that of the evolutionarily distant Arabidopsis thaliana display parallel function and establish a plant-specific solute transport profile.

Science.gov (United States)

Schein, Jessica R; Hunt, Kevin A; Minton, Janet A; Schultes, Neil P; Mourad, George S

2013-09-01

The single cell alga Chlamydomonas reinhardtii is capable of importing purines as nitrogen sources. An analysis of the annotated C. reinhardtii genome reveals at least three distinct gene families encoding for known nucleobase transporters. In this study the solute transport and binding properties for the lone C. reinhardtii nucleobase cation symporter 1 (CrNCS1) are determined through heterologous expression in Saccharomyces cerevisiae. CrNCS1 acts as a transporter of adenine, guanine, uracil and allantoin, sharing similar - but not identical - solute recognition specificity with the evolutionary distant NCS1 from Arabidopsis thaliana. The results suggest that the solute specificity for plant NCS1 occurred early in plant evolution and are distinct from solute transport specificities of single cell fungal NCS1 proteins. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Distinct metal-exchange pathways of doped Ag25 nanoclusters

KAUST Repository

Bootharaju, Megalamane Siddaramappa

2016-09-09

Atomically precise metal nanoclusters (NCs) containing more than one type of metal atom (i.e., doped or alloyed), due to synergistic effects, open new avenues for engineering the catalytic and optical properties of NCs in a manner that homometal NCs cannot. Unfortunately, it is still a major challenge to controllably introduce multimetallic dopants in NCs, understanding the dopants\\' positions, mechanism, and synergistic effects. To overcome these challenges, we designed a metal-exchange approach involving NCs as molecular templates and metal ions as the source of the incoming dopant. In particular, two structurally similar monodoped silver-rich NCs, [MAg24(SR)(18)](2-) (M = Pd/Pt and SR: thiolate), were synthesized as templates to study their mechanistic transformation in response to the introduction of gold atoms. The controllable incorporation of Au atoms into the MAg24 framework facilitated the elucidation of distinct doping pathways through high-resolution mass spectrometry, optical spectroscopy and elemental analysis. Interestingly, gold replaced the central Pd atom of [PdAg24(SR)(18)](2-) clusters to produce predominantly bimetallic [AuAg24(SR)(18)](-) clusters along with a minor product of an [Au2Ag23(SR)(18)](-) cluster. In contrast, the central Pt atom remained intact in [PtAg24(SR)(18)](2-) clusters, and gold replaced the noncentral Ag atoms to form trimetallic [AuxPtAg24-x(SR)(18)](2-) NCs, where x = 1-2, with a portion of the starting [PtAg24(SR)(18)](2-) NCs remaining. This study reveals some of the unusual metal-exchange pathways of doped NCs and the important role played by the initial metal dopant in directing the position of a second dopant in the final product.

Gender role attitudes, awareness and experiences of non-consensual sex among university students in Shanghai, China.

Science.gov (United States)

Zuo, Xiayun; Lou, Chaohua; Gao, Ersheng; Lian, Qiguo; Shah, Iqbal H

2018-03-15

Non-consensual sex (NCS) among young people, an important subject with public health and human rights implications, was less studied in China. This study is to investigate the NCS awareness and victimization of university students in Shanghai, China and whether they were associated with adolescent gender-role attitudes. Gender-role attitudes, awareness and victimization of different forms of NCS were examined among 1099 undergraduates (430 males and 669 females) in four universities in Shanghai using computer-assisted self-interview approach. University students held relatively egalitarian attitude to gender roles. Gender difference existed that girls desired to be more equal in social status and resource sharing while more endorsed the submissiveness for women in sexual interaction than boys. They held low vigilance on the risk of various forms of NCS, with the mean score on perception of NCS among boys (5.67) lower than that among girls (6.37). Boys who adhered to traditional gender norms were less likely to aware the nature of NCS (β = - 0.6107, p = 0.0389). Compared with boys, higher proportion of girls had been the victims of verbal harassment, unwanted touch, fondling, and penetrative sexual intercourse. Multivariable analysis revealed that girls who held more traditional gender-role attitudes were more vulnerable to physical NCS (OR = 1.41, p = 0.0558). The weakening but still existing traditional gender norms had contributions in explaining the gender difference on the low vigilance of NCS and higher prevalence of victimization among university students in Shanghai, China. Interventions should be taken to challenge the traditional gender norms in individual and structural level, and promote the society to understand the nature of NCS better as well as enhance negotiation skills of adolescents and young people that prevent them from potentially risky situations or relationships.

TiO2 Films Modified with Au Nanoclusters as Self-Cleaning Surfaces under Visible Light

Directory of Open Access Journals (Sweden)

Ting-Wei Liao

2018-01-01

Full Text Available In this study, we applied cluster beam deposition (CBD as a new approach for fabricating efficient plasmon-based photocatalytic materials. Au nanoclusters (AuNCs produced in the gas phase were deposited on TiO2 P25-coated silicon wafers with coverage ranging from 2 to 8 atomic monolayer (ML equivalents. Scanning Electron Microscopy (SEM images of the AuNCs modified TiO2 P25 films show that the surface is uniformly covered by the AuNCs that remain isolated at low coverage (2 ML, 4 ML and aggregate at higher coverage (8 ML. A clear relationship between AuNCs coverage and photocatalytic activity towards stearic acid photo-oxidation was measured, both under ultraviolet and green light illumination. TiO2 P25 covered with 4 ML AuNCs showed the best stearic acid photo-oxidation performance under green light illumination (Formal Quantum Efficiency 1.6 × 10−6 over a period of 93 h. These results demonstrate the large potential of gas-phase AuNCs beam deposition technology for the fabrication of visible light active plasmonic photocatalysts.

Highly Compressible Carbon Sponge Supercapacitor Electrode with Enhanced Performance by Growing Nickel-Cobalt Sulfide Nanosheets.

Science.gov (United States)

Liang, Xu; Nie, Kaiwen; Ding, Xian; Dang, Liqin; Sun, Jie; Shi, Feng; Xu, Hua; Jiang, Ruibin; He, Xuexia; Liu, Zonghuai; Lei, Zhibin

2018-03-28

The development of compressible supercapacitor highly relies on the innovative design of electrode materials with both superior compression property and high capacitive performance. This work reports a highly compressible supercapacitor electrode which is prepared by growing electroactive NiCo 2 S 4 (NCS) nanosheets on the compressible carbon sponge (CS). The strong adhesion of the metallic conductive NCS nanosheets to the highly porous carbon scaffolds enable the CS-NCS composite electrode to exhibit an enhanced conductivity and ideal structural integrity during repeated compression-release cycles. Accordingly, the CS-NCS composite electrode delivers a specific capacitance of 1093 F g -1 at 0.5 A g -1 and remarkable rate performance with 91% capacitance retention in the range of 0.5-20 A g -1 . Capacitance performance under the strain of 60% shows that the incorporation of NCS nanosheets in CS scaffolds leads to over five times enhancement in gravimetric capacitance and 17 times enhancement in volumetric capacitance. These performances enable the CS-NCS composite to be one of the promising candidates for potential applications in compressible electrochemical energy storage devices.

Two types of the relation between the intensity and the life time of photoluminescence of core/shell semiconductor quantum dots: Important role of Coulomb field and tunneling transitions

Energy Technology Data Exchange (ETDEWEB)

Osad' ko, I. S., E-mail: osadko@isan.troitsk.ru [Institute for spectroscopy RAS, Troitsk, 142190 Moscow (Russian Federation)

2014-10-28

It has been recently found [Gh. Galland, Y. Ghosh, A. Steinbrück, M. Sykora, J. A. Hollingsworth, and V. I. Klimov, Nature (London) 479, 203 (2011)] that semiconductor core/shell nanocrystals (NCs) with blinking photoluminescence (PL) can be of “A” or “B” type. NCs of A-type exhibit correlation between the intensity of PL and the life time. In NCs of B-type such correlation is absent. Simple model based on combination of the charging model and the two-level system model is proposed for describing emissive properties of NCs of both types. The model invokes fluctuations of emission ability γ{sub em} of NC to explain the emissive properties of NCs of B-type. Our combined model is also in agreement with anticorrelation between the duration τ{sub off} of off intervals and PL life time t{sub off} in off intervals found recently for NCs of A-type in the experiment [A. A. Cordones, T. J. Bixby, and S. R. Leone, Nano Lett. 11, 3366 (2011)].

User-Generated Services Composition in Smart Multi-User Environments

Directory of Open Access Journals (Sweden)

Vincenzo Catania

2017-09-01

Full Text Available The increasing complexity shown in Smart Environments, together with the spread of social networks, is increasingly moving the role of users from simple information and services consumers to actual producers. In this work, we focus on security issues raised by a particular kind of services: those generated by users. User-Generated Services (UGSs are characterized by a set of features that distinguish them from conventional services. To cope with UGS security problems, we introduce three different policy management models, analyzing benefits and drawbacks of each approach. Finally, we propose a cloud-based solution that enables the composition of multiple UGSs and policy models, allowing users’ devices to share features and services in Internet of Things (IoT based scenarios.

Selection of Minerals properties using service oriented architecture

Directory of Open Access Journals (Sweden)

Pavel Horovčák

2009-09-01

Full Text Available Continually and impressive amplification of internet technologies development and implementation enables the creationof productive, efficient, useful and interactive web applications. The contribution briefly characterizes SOA (Service OrientedArchitecture, WS (Web Service and AJAX (Asynchronous JavaScript And XML technology and illustrates advantages of AJAX and WSintegration on application example for interactive selection of one or more minerals according to actually chosen selection criteria.Contribution presents three created web services (service for creating of web page’s select list based on given database table content,service for selection of one or a group of minerals according to specified criteria from the group of database tables, and service forcorrect depiction of chemical formulas on web page. The application makes use of two web services on the server side and one webservice plus Ajax technology on the client’s side. Application’s client’s side presents integration of these web services in a dynamic wayby means of Ajax technology and at the same time it is a mashup demonstration.

A gold nanocluster-based fluorescent probe for simultaneous pH and temperature sensing and its application to cellular imaging and logic gates

Science.gov (United States)

Wu, Yun-Tse; Shanmugam, Chandirasekar; Tseng, Wei-Bin; Hiseh, Ming-Mu; Tseng, Wei-Lung

2016-05-01

Metal nanocluster-based nanomaterials for the simultaneous determination of temperature and pH variations in micro-environments are still a challenge. In this study, we develop a dual-emission fluorescent probe consisting of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) and fluorescein-5-isothiocyanate (FITC) as temperature- and pH-responsive fluorescence signals. Under single wavelength excitation the FITC/BSA-AuNCs exhibited well-separated dual emission bands at 525 and 670 nm. When FITC was used as a reference fluorophore, FITC/BSA-AuNCs showed a good linear response over the temperature range 1-71 °C and offered temperature-independent spectral shifts, temperature accuracy, activation energy, and reusability. The possible mechanism for high temperature-induced fluorescence quenching of FITC/BSA-AuNCs could be attributed to a weakening of the Au-S bond, thereby lowering the charge transfer from BSA to AuNCs. Additionally, the pH- and temperature-responsive properties of FITC/BSA-AuNCs allow simultaneous temperature sensing from 21 to 41 °C (at intervals of 5 °C) and pH from 6.0 to 8.0 (at intervals of 0.5 pH unit), facilitating the construction of two-input AND logic gates. Three-input AND logic gates were also designed using temperature, pH, and trypsin as inputs. The practicality of using FITC/BSA-AuNCs to determine the temperature and pH changes in HeLa cells is also validated.Metal nanocluster-based nanomaterials for the simultaneous determination of temperature and pH variations in micro-environments are still a challenge. In this study, we develop a dual-emission fluorescent probe consisting of bovine serum albumin-stabilized gold nanoclusters (BSA-AuNCs) and fluorescein-5-isothiocyanate (FITC) as temperature- and pH-responsive fluorescence signals. Under single wavelength excitation the FITC/BSA-AuNCs exhibited well-separated dual emission bands at 525 and 670 nm. When FITC was used as a reference fluorophore, FITC/BSA-AuNCs showed a

Characterization and Health Risk Assessment of Volatile Organic Compounds in Gas Service Station Workers

Directory of Open Access Journals (Sweden)

Duangduan Yimrungruang

2008-07-01

Full Text Available Gas service station workers who work near volatile organic compounds (VOCs sources, such as gasoline vapor emissions, and motor vehicle exhausts, may be exposed to highly elevated VOCs levels. This study investigates air samples from gas service stations in Thailand to evaluate the health risks following inhalation exposure. Personal air samplings were obtained at nine gas service stations in Chonburi, Thailand from October to December 2007. The concentrations of benzene, toluene, ethylbenzene, xylenes, and hexane in the air from the workplaces were significantly higher than in a control group of office workers (p<0.05. However, all VOCs in these air samples were lower than TWA limit of Thailand and the OSHA standard. Samples of urine, collected after 8-h work periods which were analyzed for VOCs metabolites, including t,t muconic acid, hippuric acid, mandelic acid and m-hippuric acid, demonstrate that the average levels of metabolites in gas service station workers and in controls were close, except for t,t muconic acid of gas service station workers which displayed higher levels than the in the controls. The lifetime cancer and noncancer risks for the workers exposed to VOCs were also assessed. Results show that all nine gas service stations in this study had a elevated lifetime cancer risk ranging from 53 to 630 per million, thus exceeding the normal risk of 1 per million. For noncancer risks, the levels in all gas stations ranged between 0.03 and 0.4, which is well below the reference hazard level of 1.0. Benzene may the most important cause of both cancer and noncancer risk followed by 1,3 butadiene.

Community Service Programs: A Model for At-Risk Long-Term-Suspended Students

Science.gov (United States)

Hall, Brenda S.; Rubin, Tova

2008-01-01

Each year in the United States, millions of students experience suspension from public schools (Mendez & Knoff, 2003). Community service programs provide one means to address the school suspension problem. These initiatives are characterized by volunteer service placements within community nonprofit organizations for skill and personal…

New method for estimating clustering of DNA lesions induced by physical/chemical mutagens using fluorescence anisotropy.

Science.gov (United States)

Akamatsu, Ken; Shikazono, Naoya; Saito, Takeshi

2017-11-01

We have developed a new method for estimating the localization of DNA damage such as apurinic/apyrimidinic sites (APs) on DNA using fluorescence anisotropy. This method is aimed at characterizing clustered DNA damage produced by DNA-damaging agents such as ionizing radiation and genotoxic chemicals. A fluorescent probe with an aminooxy group (AlexaFluor488) was used to label APs. We prepared a pUC19 plasmid with APs by heating under acidic conditions as a model for damaged DNA, and subsequently labeled the APs. We found that the observed fluorescence anisotropy (r obs ) decreases as averaged AP density (λ AP : number of APs per base pair) increases due to homo-FRET, and that the APs were randomly distributed. We applied this method to three DNA-damaging agents, 60 Co γ-rays, methyl methanesulfonate (MMS), and neocarzinostatin (NCS). We found that r obs -λ AP relationships differed significantly between MMS and NCS. At low AP density (λ AP  < 0.001), the APs induced by MMS seemed to not be closely distributed, whereas those induced by NCS were remarkably clustered. In contrast, the AP clustering induced by 60 Co γ-rays was similar to, but potentially more likely to occur than, random distribution. This simple method can be used to estimate mutagenicity of ionizing radiation and genotoxic chemicals. Copyright © 2017 Elsevier Inc. All rights reserved.

A viewpoint on nearly conformally symmetric manifold

International Nuclear Information System (INIS)

Rahman, M.S.

1990-06-01

Some observations, with definition, on Nearly Conformally Symmetric (NCS) manifold are made. A number of theorems concerning conformal change of metric and parallel tensors on NCS manifolds are presented. It is illustrated that a manifold M = R n-1 x R + 1 , endowed with a special metric, is NCS but not of harmonic curvature. (author). 8 refs

Enhanced Emission from Single Isolated Gold Quantum Dots Investigated Using Two-Photon-Excited Fluorescence Near-Field Scanning Optical Microscopy.

Science.gov (United States)

Abeyasinghe, Neranga; Kumar, Santosh; Sun, Kai; Mansfield, John F; Jin, Rongchao; Goodson, Theodore

2016-12-21

New approaches in molecular nanoscopy are greatly desired for interrogation of biological, organic, and inorganic objects with sizes below the diffraction limit. Our current work investigates emergent monolayer-protected gold quantum dots (nanoclusters, NCs) composed of 25 Au atoms by utilizing two-photon-excited fluorescence (TPEF) near-field scanning optical microscopy (NSOM) at single NC concentrations. Here, we demonstrate an approach to synthesize and isolate single NCs on solid glass substrates. Subsequent investigation of the NCs using TPEF NSOM reveals that, even when they are separated by distances of several tens of nanometers, we can excite and interrogate single NCs individually. Interestingly, we observe an enhanced two-photon absorption (TPA) cross section for single Au 25 NCs that can be attributed to few-atom local field effects and to local field-induced microscopic cascading, indicating their potential for use in ultrasensitive sensing, disease diagnostics, cancer cell therapy, and molecular computers. Finally, we report room-temperature aperture-based TPEF NSOM imaging of these NCs for the first time at 30 nm point resolution, which is a ∼5-fold improvement compared to the previous best result for the same technique. This report unveils the unique combination of an unusually large TPA cross section and the high photostability of Au NCs to (non-destructively) investigate stable isolated single NCs using TPEF NSOM. This is the first reported optical study of monolayer-protected single quantum clusters, opening some very promising opportunities in spectroscopy of nanosized objects, bioimaging, ultrasensitive sensing, molecular computers, and high-density data storage.

Hierarchical Co3O4/PANI hollow nanocages: Synthesis and application for electrode materials of supercapacitors

Science.gov (United States)

Ren, Xiaohu; Fan, Huiqing; Ma, Jiangwei; Wang, Chao; Zhang, Mingchang; Zhao, Nan

2018-05-01

Hierarchically hollow Co3O4/polyaniline nanocages (Co3O4/PANI NCs) with enhanced specific capacitance and cycle performance for electrode material of supercapacitors are fabricated by combining self-sacrificing template and in situ polymerization route. Benefiting from the good conductivity of PANI improving an electron transport rate as well as high specific surface area from such a hollow structure, the electrode made of Co3O4/PANI NCs exhibits a large specific capacitance of 1301 F/g at the current density of 1 A/g, a much enhancement is obtained as compared with the pristine Co3O4 NCs electrode. The contact resistance (Re), charge-transfer (Rct) and Warburg resistance of Co3O4/PANI NCs electrode is significantly lower than that of the pristine Co3O4 NCs electrode, indicating the enhanced electrical conductivity. In addition, the Co3O4/PANI NCs electrode also displays superior cycling stability with 90 % capacitance retention after 2000 cycles. Moreover, an aqueous asymmetric supercapacitor was successfully assembled using Co3O4/PANI NCs as the positive electrode and activated carbon (AC) as the negative electrode, the assembled device exhibits a superior energy density of 41.5 Wh/kg at 0.8 kW/kg, outstanding power density of 15.9 kW/kg at 18.4 Wh/kg, which significantly transcending those of most previously reported. These results demonstrate that the hierarchically hollow Co3O4/PANI NCs composites have a potential for fabricating electrode of supercapacitors.

Morphology engineering of ZnO nanostructures for high performance supercapacitors: enhanced electrochemistry of ZnO nanocones compared to ZnO nanowires

Science.gov (United States)

He, Xiaoli; Yoo, Joung Eun; Lee, Min Ho; Bae, Joonho

2017-06-01

In this work, the morphology of ZnO nanostructures is engineered to demonstrate enhanced supercapacitor characteristics of ZnO nanocones (NCs) compared to ZnO nanowires (NWs). ZnO NCs are obtained by chemically etching ZnO NWs. Electrochemical characteristics of ZnO NCs and NWs are extensively investigated to demonstrate morphology dependent capacitive performance of one dimensional ZnO nanostructures. Cyclic voltammetry measurements on these two kinds of electrodes in a three-electrode cell confirms that ZnO NCs exhibit a high specific capacitance of 378.5 F g-1 at a scan rate of 20 mV s-1, which is almost twice that of ZnO NWs (191.5 F g-1). The charge-discharge and electrochemical impedance spectroscopy measurements also clearly result in enhanced capacitive performance of NCs as evidenced by higher specific capacitances and lower internal resistance. Asymmetric supercapacitors are fabricated using activated carbon (AC) as the negative electrode and ZnO NWs and NCs as positive electrodes. The ZnO NC⫽AC can deliver a maximum specific capacitance of 126 F g-1 at a current density of 1.33 A g-1 with an energy density of 25.2 W h kg-1 at the power density of 896.44 W kg-1. In contrast, ZnO NW⫽AC displays 63% of the capacitance obtained from the ZnO NC⫽AC supercapacitor. The enhanced performance of NCs is attributed to the higher surface area of ZnO nanostructures after the morphology is altered from NWs to NCs.

Electronic structure and spectroscopic properties of mononuclear manganese(III) Schiff base complexes: a systematic study on [Mn(acen)X] complexes by EPR, UV/vis, and MCD spectroscopy (X = Hal, NCS).

Science.gov (United States)

Westphal, Anne; Klinkebiel, Arne; Berends, Hans-Martin; Broda, Henning; Kurz, Philipp; Tuczek, Felix

2013-03-04

The manganese(III) Schiff base complexes [Mn(acen)X] (H2acen: N,N'-ethylenebis(acetylacetone)imine, X: I(-), Br(-), Cl(-), NCS(-)) are considered as model systems for a combined study of the electronic structure using vibrational, UV/vis absorption, parallel-mode electron paramagnetic resonance (EPR) and low-temperature magnetic circular dichroism (MCD) spectroscopy. By variation of the co-ligand X, the influence of the axial ligand field within a given square-pyramidal coordination geometry on the UV/vis, EPR, and MCD spectra of the title compounds is investigated. Between 25000 and 35000 cm(-1), the low-temperature MCD spectra are dominated by two very intense, oppositely signed pseudo-A terms, referred to as "double pseudo-A terms", which change their signs within the [Mn(acen)X] series dependent on the axial ligand X. Based on molecular orbital (MO) and symmetry considerations, these features are assigned to π(n.b.)(s, a) → yz, z(2) ligand-to-metal charge transfer transitions. The individual MCD signs are directly determined from the calculated MOs of the [Mn(acen)X] complexes. The observed sign change is explained by an inversion of symmetry among the π(n.b.)(s, a) donor orbitals which leads to an interchange of the positive and negative pseudo-A terms constituting the "double pseudo-A term".

Teaching Qualitative Research for Human Services Students: A Three-Phase Model

Science.gov (United States)

Goussinsky, Ruhama; Reshef, Arie; Yanay-Ventura, Galit; Yassour-Borochowitz, Dalit

2011-01-01

Qualitative research is an inherent part of the human services profession, since it emphasizes the great and multifaceted complexity characterizing human experience and the sociocultural context in which humans act. In the department of human services at Emek Yezreel College, Israel, we have developed a three-phase model to ensure a relatively…

Informal learning processes in support of clinical service delivery in a service-oriented community pharmacy.

Science.gov (United States)

Patterson, Brandon J; Bakken, Brianne K; Doucette, William R; Urmie, Julie M; McDonough, Randal P

The evolving health care system necessitates pharmacy organizations' adjustments by delivering new services and establishing inter-organizational relationships. One approach supporting pharmacy organizations in making changes may be informal learning by technicians, pharmacists, and pharmacy owners. Informal learning is characterized by a four-step cycle including intent to learn, action, feedback, and reflection. This framework helps explain individual and organizational factors that influence learning processes within an organization as well as the individual and organizational outcomes of those learning processes. A case study of an Iowa independent community pharmacy with years of experience in offering patient care services was made. Nine semi-structured interviews with pharmacy personnel revealed initial evidence in support of the informal learning model in practice. Future research could investigate more fully the informal learning model in delivery of patient care services in community pharmacies. Copyright © 2016 Elsevier Inc. All rights reserved.

Integration of G-quadruplex and DNA-templated Ag NCs for nonarithmetic information processing† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c7sc00361g Click here for additional data file.

Science.gov (United States)

Gao, Ru-Ru; Lv, Xiao-Yan; Zhu, Yan-Yan; Zhang, Yi-Wei

2017-01-01

To create sophisticated molecular logic circuits from scratch, you may not believe how common the building blocks can be and how diverse and powerful such circuits can be when scaled up. Using the two simple building blocks of G-quadruplex and silver nanoclusters (Ag NCs), we experimentally construct a series of multifunctional, label-free, and multi-output logic circuits to perform nonarithmetic functions: a 1-to-2 decoder, a 4-to-2 encoder, an 8-to-3 encoder, dual transfer gates, a 2 : 1 multiplexer, and a 1 : 2 demultiplexer. Moreover, a parity checker which is capable of identifying odd and even numbers from natural numbers is constructed conceptually. Finally, a multi-valued logic gate (ternary inhibit gate) is readily achieved by taking this DNA/Ag NC system as a universal platform. All of the above logic circuits share the same building blocks, indicating the great prospects of the assembly of nanomaterials and DNA for biochemical logic devices. Considering its biocompatibility, the novel prototypes developed here may have potential applications in the fields of biological computers and medical diagnosis and serve as a promising proof of principle in the not-too-distant future. PMID:28626564

Oxygen sensitive polymeric nanocapsules for optical dissolved oxygen sensors

Science.gov (United States)

Sun, Zhijuan; Cai, Chenxin; Guo, Fei; Ye, Changhuai; Luo, Yingwu; Ye, Shuming; Luo, Jianchao; Zhu, Fan; Jiang, Chunyue

2018-04-01

Immobilization of the oxygen-sensitive probes (OSPs) in the host matrix greatly impacts the performance and long-term usage of the optical dissolved oxygen (DO) sensors. In this work, fluorescent dyes, as the OSPs, were encapsulated with a crosslinked fluorinated polymer shell by interfacial confined reversible addition fragmentation chain transfer miniemulsion polymerization to fabricate oxygen sensitive polymeric nanocapsules (NCs). The location of fluorescent dyes and the fluorescent properties of the NCs were fully characterized by fourier transform infrared spectrometer, x-ray photoelectron spectrometer and fluorescent spectrum. Dye-encapsulated capacity can be precisely tuned from 0 to 1.3 wt% without self-quenching of the fluorescent dye. The crosslinked fluorinated polymer shell is not only extremely high gas permeability, but also prevents the fluorescent dyes from leakage in aqueous as well as in various organic solvents, such as ethanol, acetone and tetrahydrofuran (THF). An optical DO sensor based on the oxygen sensitive NCs was fabricated, showing high sensitivity, short response time, full reversibility, and long-term operational stability of online monitoring DO. The sensitivity of the optical DO sensor is 7.02 (the ratio of the response value in fully deoxygenated and saturated oxygenated water) in the range 0.96-14.16 mg l-1 and the response time is about 14.3 s. The sensor’s work curve was fit well using the modified Stern-Volmer equation by two-site model, and its response values are hardly affected by pH ranging from 2 to 12 and keep constant during continuous measurement for 3 months. It is believed that the oxygen sensitive polymeric NCs-based optical DO sensor could be particularly useful in long-term online DO monitoring in both aqueous and organic solvent systems.

Genesis, challenges and opportunities for colloidal lead halide perovskite nanocrystals

Science.gov (United States)

Akkerman, Quinten A.; Rainò, Gabriele; Kovalenko, Maksym V.; Manna, Liberato

2018-05-01

Lead halide perovskites (LHPs) in the form of nanometre-sized colloidal crystals, or nanocrystals (NCs), have attracted the attention of diverse materials scientists due to their unique optical versatility, high photoluminescence quantum yields and facile synthesis. LHP NCs have a `soft' and predominantly ionic lattice, and their optical and electronic properties are highly tolerant to structural defects and surface states. Therefore, they cannot be approached with the same experimental mindset and theoretical framework as conventional semiconductor NCs. In this Review, we discuss LHP NCs historical and current research pursuits, challenges in applications, and the related present and future mitigation strategies explored.

Nutcracker Syndrome and Sickle Cell Trait: A Perfect Storm for Hematuria.

Science.gov (United States)

Ahmad, Amier; McElwee, Samuel K; Kraemer, Ryan R

2017-05-01

We describe the case of a 27-year-old woman with a history of sickle cell trait (SCT) who presented with several months of hematuria and was found to have nutcracker syndrome (NCS). While SCT is a common cause of hematuria resulting from renal papillary necrosis, our patient had concomitant abdominal pain and anemia, prompting further evaluation and the subsequent diagnosis of NCS. Interestingly, the anoxia in the left renal vein from NCS predisposes patients with SCT to sickling. Our case highlights key clinical features of both NCS and SCT and the relationship between the two disease processes.

Event-Driven Control for Networked Control Systems With Quantization and Markov Packet Losses.

Science.gov (United States)

Yang, Hongjiu; Xu, Yang; Zhang, Jinhui

2016-05-23

In this paper, event-driven is used in a networked control system (NCS) which is subjected to the effect of quantization and packet losses. A discrete event-detector is used to monitor specific events in the NCS. Both an arbitrary region quantizer and Markov jump packet losses are also considered for the NCS. Based on zoom strategy and Lyapunov theory, a complete proof is given to guarantee mean square stability of the closed-loop system. Stabilization of the NCS is ensured by designing a feedback controller. Lastly, an inverted pendulum model is given to show the advantages and effectiveness of the proposed results.

Co-Au core-shell nanocrystals formed by sequential ion implantation into SiO2

International Nuclear Information System (INIS)

Kluth, P.; Hoy, B.; Johannessen, B.; Dunn, S. G.; Foran, G. J.; Ridgway, M. C.

2006-01-01

Co-Au core-shell nanocrystals (NCs) were formed by sequential ion implantation of Au and Co into thin SiO 2 . The NCs were investigated by means of transmission electron microscopy and extended x-ray absorption fine structure spectroscopy. The latter reveals a bond length expansion in the Co core compared to monatomic Co NCs. Concomitantly, a significant contraction of the bond length and a significant reduction of the effective Au-Au coordination number were observed in the Au shells. Increased Debye-Waller factors indicate significant strain in the NCs. These experimental results verify recent theoretical predictions

Probing surface states in PbS nanocrystal films using pentacene field effect transistors: controlling carrier concentration and charge transport in pentacene.

Science.gov (United States)

Park, Byoungnam; Whitham, Kevin; Bian, Kaifu; Lim, Yee-Fun; Hanrath, Tobias

2014-12-21

We used a bilayer field effect transistor (FET) consisting of a thin PbS nanocrystals (NCs) film interfaced with vacuum-deposited pentacene to probe trap states in NCs. We interpret the observed threshold voltage shift in context of charge carrier trapping by PbS NCs and relate the magnitude of the threshold voltage shift to the number of trapped carriers. We explored a series of NC surface ligands to modify the interface between PbS NCs and pentacene and demonstrate the impact of interface chemistry on charge carrier density and the FET mobility in a pentacene FET.

Use of magnetic tape services in the field of scientific and technical information

International Nuclear Information System (INIS)

Jankowski, L.; Toepfer, S.; Riedel, F.; Weber, A.; Hertel, L.

1977-04-01

The Unitid Software System (USS) is analyzed and characterized. The adaption of USS to the Automated Document Retrieval System (AIDOS) is discussed and the feasibility of establishing a apecial information service on the basis of several magnetic tape services is shown

Sensitive and selective detection of Hg2+ and Cu2+ ions by fluorescent Ag nanoclusters synthesized via a hydrothermal method

Science.gov (United States)

Liu, Jing; Ren, Xiangling; Meng, Xianwei; Fang, Zheng; Tang, Fangqiong

2013-09-01

An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 μM or 10 nM to 30 μM, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a reusable detection method for Cu2+. Furthermore, the different quenching phenomena caused by the two metals ions such as changes in visible colour, shifts of UV absorbance peaks and changes in size of Ag NCs make it easy to distinguish between them. Therefore the easily synthesized fluorescent Ag NCs may have great potential as Hg2+ and Cu2+ ions sensors.An easily prepared fluorescent Ag nanoclusters (Ag NCs) probe for the sensitive and selective detection of Hg2+ and Cu2+ ions was developed here. The Ag NCs were synthesized by using polymethacrylic acid sodium salt as a template via a convenient hydrothermal process. The as-prepared fluorescent Ag NCs were monodispersed, uniform and less than 2 nm in diameter, and can be quenched in the presence of mercury (Hg2+) or copper (Cu2+) ions. Excellent linear relationships existed between the quenching degree of the Ag NCs and the concentrations of Hg2+ or Cu2+ ions in the range of 10 nM to 20 μM or 10 nM to 30 μM, respectively. By using ethylenediaminetetraacetate (EDTA) as the masking agent of Cu2+, Hg2+ was exclusively detected in coexistence with Cu2+ with high sensitivity (LOD = 10 nM), which also provided a

An Energy Efficient Neuromorphic Computing System Using Real Time Sensing Method

DEFF Research Database (Denmark)

Farkhani, Hooman; Tohidi, Mohammad; Farkhani, Sadaf

2017-01-01

In spintronic-based neuromorphic computing systems (NCS), the switching of magnetic moment in a magnetic tunnel junction (MTJ) is used to mimic neuron firing. However, the stochastic switching behavior of the MTJ and process variations effect leads to extra stimulation time. This leads to extra...... energy consumption and delay of such NCSs. In this paper, a new real-time sensing (RTS) circuit is proposed to track the MTJ state and terminate stimulation phase immediately after MTJ switching. This leads to significant degradation in energy consumption and delay of NCS. The simulation results using...... a 65-nm CMOS technology and a 40-nm MTJ technology confirm that the energy consumption of a RTS-based NCS is improved by 50% in comparison with a typical NCS. Moreover, utilizing RTS circuit improves the overall speed of an NCS by 2.75x....

In vivo molecular photoacoustic tomography of melanomas targeted by bioconjugated gold nanocages.

Science.gov (United States)

Kim, Chulhong; Cho, Eun Chul; Chen, Jingyi; Song, Kwang Hyun; Au, Leslie; Favazza, Christopher; Zhang, Qiang; Cobley, Claire M; Gao, Feng; Xia, Younan; Wang, Lihong V

2010-08-24

Early diagnosis, accurate staging, and image-guided resection of melanomas remain crucial clinical objectives for improving patient survival and treatment outcomes. Conventional techniques cannot meet this demand because of the low sensitivity, low specificity, poor spatial resolution, shallow penetration, and/or ionizing radiation. Here we overcome such limitations by combining high-resolution photoacoustic tomography (PAT) with extraordinarily optical absorbing gold nanocages (AuNCs). When bioconjugated with [Nle(4),D-Phe(7)]-alpha-melanocyte-stimulating hormone, the AuNCs can serve as a novel contrast agent for in vivo molecular PAT of melanomas with both exquisite sensitivity and high specificity. The bioconjugated AuNCs enhanced contrast approximately 300% more than the control, PEGylated AuNCs. The in vivo PAT quantification of the amount of AuNCs accumulated in melanomas was further validated with inductively coupled plasma mass spectrometry (ICP-MS).

In vivo molecular photoacoustic tomography of melanomas targeted by bio-conjugated gold nanocages

Science.gov (United States)

Kim, Chulhong; Cho, Eun Chul; Chen, Jingyi; Song, Kwang Hyun; Au, Leslie; Favazza, Christopher; Zhang, Qiang; Cobley, Claire M.; Gao, Feng; Xia, Younan; Wang, Lihong V.

2010-01-01

Early diagnosis, accurate staging, and image-guided resection of melanomas remain crucial clinical objectives for improving patient survival and treatment outcomes. Conventional techniques cannot meet this demand because of the low sensitivity, low specificity, poor spatial resolution, shallow penetration, and/or ionizing radiation. Here we overcome such limitations by combining high-resolution photoacoustic tomography (PAT) with extraordinarily optical absorbing gold nanocages (AuNCs). When bio-conjugated with [Nle4,D-Phe7]-α-melanocyte-stimulating hormone, the AuNCs can serve as a novel contrast agent for in vivo molecular PAT of melanomas with both exquisite sensitivity and high specificity. The bio-conjugated AuNCs enhanced contrast ~300% more than the control, PEGylated AuNCs. The in vivo PAT quantification of the amount of AuNCs accumulated in melanomas was further validated with inductively coupled plasma mass spectrometry (ICP-MS). PMID:20731439

[Competencies in the education of nursing technicians to implement the nursing care systematization].

Science.gov (United States)

da Cruz, Andrea de Mello Pereira; Almeida, Miriam de Abreu

2010-12-01

This is a qualitative, exploratory and descriptive study whose general objective was to learn, considering the perspective of the nursing technician who works in school hospitals, the competencies developed during their educational process to implement the Nursing Care Systematization (NCS). Data collection and analysis were carried out through a focal group, with content analysis and nursing technicians. Two thematic categories emerged: The participation of the nursing technician in the NCS and The competencies in the education of the nursing technician. Each one received two subcategories: Conception of the NCS and (De)valuation of the NCS, Technical-scientific competency and Competency in the interpersonal relationship, respectively. It was observed that the NCS must be shared, discussed and made public among nursing professionals, so that they may acknowledge themselves as the leading actors of their methodology and be aware that their practices determine the results.

Characterization of Fernald Silo 3 Waste

Energy Technology Data Exchange (ETDEWEB)

Langton, C.A.

2001-04-04

This report summarizes characterization results for uranium residues from the Fernald Environmental Management Project (FEMP) Operable Unit (OU-4). These residues are currently stored in a one-million-gallon concrete silo, Silo 3, at the DOE Fernald Site, Ohio. Characterization of the Silo 3 waste is the first part of a three part study requested by Rocky Mountain Remedial Services (RMRS) through a Work for others Agreement, WFO-00-007, between the Westinghouse Savannah River Company (WSRC) and RMRS. Parts 2 and 3 of this effort include bench- and pilot-scale testing.

Quasi-self-trapped Frenkel-exciton near-UV luminescence with large Stokes shift in wide-bandgap Cs4PbCl6 nanocrystals

Science.gov (United States)

Zhang, Yumeng; Fan, Baolu; Liu, Yuzhen; Li, Hongxia; Deng, Kaiming; Fan, Jiyang

2018-04-01

Inorganic lead halide perovskite nanocrystals (NCs) have attracted great interest owing to their superior luminescence and optoelectronic properties. In comparison to cubic CsPbX3 (X = Cl, Br, or I) that has visible luminescence, trigonal Cs4PbX6 has a much larger bandgap and distinct optical properties. Little has been known about the luminescence properties of the Cs4PbX6 NCs. In this study, we synthesize the well-crystallized Cs4PbCl6 NCs with sizes of 2.2-11.8 nm, which exhibit stable and near-UV luminescence (with a lifetime of 19.7-24.2 ns) with a remarkable quantum confinement effect at room temperature. In comparison to the negligible Stokes shift in the CsPbCl3 NCs, the Stokes shift of the Cs4PbCl6 NCs is very large (0.91 eV). The experimental results in combination with the first-principles calculations reveal that the near-UV luminescence of the Cs4PbCl6 NCs stems from the Frenkel excitons self-trapped in the isolated PbCl64- octahedrons. This is different from the CsPbCl3 NCs whose luminescence originates from the free Wannier excitons. The theoretical model based on the lattice relaxation is proposed to account for the large Stokes shift and its abnormal decrease with the decreasing particle size.

Stress evolution of Ge nanocrystals in dielectric matrices

Science.gov (United States)

Bahariqushchi, Rahim; Raciti, Rosario; Emre Kasapoğlu, Ahmet; Gür, Emre; Sezen, Meltem; Kalay, Eren; Mirabella, Salvatore; Aydinli, A.

2018-05-01

Germanium nanocrystals (Ge NCs) embedded in single and multilayer silicon oxide and silicon nitride matrices have been synthesized using plasma enhanced chemical vapor deposition followed by conventional furnace annealing or rapid thermal processing in N2 ambient. Compositions of the films were determined by Rutherford backscattering spectrometry and x-ray photoelectron spectroscopy. The formation of NCs under suitable process conditions was observed with high resolution transmission electron microscope micrographs and Raman spectroscopy. Stress measurements were done using Raman shifts of the Ge optical phonon line at 300.7 cm-1. The effect of the embedding matrix and annealing methods on Ge NC formation were investigated. In addition to Ge NCs in single layer samples, the stress on Ge NCs in multilayer samples was also analyzed. Multilayers of Ge NCs in a silicon nitride matrix separated by dielectric buffer layers to control the size and density of NCs were fabricated. Multilayers consisted of SiN y :Ge ultrathin films sandwiched between either SiO2 or Si3N4 by the proper choice of buffer material. We demonstrated that it is possible to tune the stress state of Ge NCs from compressive to tensile, a desirable property for optoelectronic applications. We also observed that there is a correlation between the stress and the crystallization threshold in which the compressive stress enhances the crystallization, while the tensile stress suppresses the process.

High Efficiency Dye-sensitized Solar Cells Constructed with Composites of TiO2 and the Hot-bubbling Synthesized Ultra-Small SnO2 Nanocrystals.

Science.gov (United States)

Mao, Xiaoli; Zhou, Ru; Zhang, Shouwei; Ding, Liping; Wan, Lei; Qin, Shengxian; Chen, Zhesheng; Xu, Jinzhang; Miao, Shiding

2016-01-13

An efficient photo-anode for the dye-sensitized solar cells (DSSCs) should have features of high loading of dye molecules, favorable band alignments and good efficiency in electron transport. Herein, the 3.4 nm-sized SnO2 nanocrystals (NCs) of high crystallinity, synthesized via the hot-bubbling method, were incorporated with the commercial TiO2 (P25) particles to fabricate the photo-anodes. The optimal percentage of the doped SnO2 NCs was found at ~7.5% (SnO2/TiO2, w/w), and the fabricated DSSC delivers a power conversion efficiency up to 6.7%, which is 1.52 times of the P25 based DSSCs. The ultra-small SnO2 NCs offer three benefits, (1) the incorporation of SnO2 NCs enlarges surface areas of the photo-anode films, and higher dye-loading amounts were achieved; (2) the high charge mobility provided by SnO2 was confirmed to accelerate the electron transport, and the photo-electron recombination was suppressed by the highly-crystallized NCs; (3) the conduction band minimum (CBM) of the SnO2 NCs was uplifted due to the quantum size effects, and this was found to alleviate the decrement in the open-circuit voltage. This work highlights great contributions of the SnO2 NCs to the improvement of the photovoltaic performances in the DSSCs.

Glutathione-stabilized Cu nanoclusters as fluorescent probes for sensing pH and vitamin B1.

Science.gov (United States)

Luo, Yawen; Miao, Hong; Yang, Xiaoming

2015-11-01

Glutathione (GSH), playing roles as both a reducing reagent and protecting ligand, has been successfully employed for synthesizing Cu nanoclusters (CuNCs@GSH) on the basis of a simple and facile approach. The as-prepared CuNCs exhibited a fluorescence emission at 600nm with a quantum yield (QY) of approximately 3.6%. Subsequently, the CuNCs described here was employed as a broad-range pH sensor by virtue of the fluorescence intensity of CuNCs responding sensitively to pH fluctuating in a linear range of 4.0-12.0. Meanwhile, these prepared CuNCs were applied for detections of vitamin B1 (VB1) on the basis of positively charged VB1 neutralizing the negative surface charge of CuNCs, thus leading to the instability and aggregations of CuNCs, and further facilitating to quench their fluorescence. In addition, the proposed analytical method permitted detecting VB1 with a linear range of 2.0×10(-8)-1.0×10(-4) mol L(-1) as well as a detection limit of 4.6×10(-9) mol L(-1). Eventually, the practicability of this sensing approach was validated by assaying VB1 in human urine samples and pharmaceutical tablets, confirming its potential to broaden avenues for assaying VB1. Copyright © 2015 Elsevier B.V. All rights reserved.

Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species.

Science.gov (United States)

Matulionyte, Marija; Dapkute, Dominyka; Budenaite, Laima; Jarockyte, Greta; Rotomskis, Ricardas

2017-02-10

In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS) of bovine serum albumin-encapsulated (BSA-Au NCs) and 2-(N-morpholino) ethanesulfonic acid (MES)capped photoluminescent gold nanoclusters (Au-MES NCs) were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.

Photoluminescent Gold Nanoclusters in Cancer Cells: Cellular Uptake, Toxicity, and Generation of Reactive Oxygen Species

Directory of Open Access Journals (Sweden)

Marija Matulionyte

2017-02-01

Full Text Available In recent years, photoluminescent gold nanoclusters have attracted considerable interest in both fundamental biomedical research and practical applications. Due to their ultrasmall size, unique molecule-like optical properties, and facile synthesis gold nanoclusters have been considered very promising photoluminescent agents for biosensing, bioimaging, and targeted therapy. Yet, interaction of such ultra-small nanoclusters with cells and other biological objects remains poorly understood. Therefore, the assessment of the biocompatibility and potential toxicity of gold nanoclusters is of major importance before their clinical application. In this study, the cellular uptake, cytotoxicity, and intracellular generation of reactive oxygen species (ROS of bovine serum albumin-encapsulated (BSA-Au NCs and 2-(N-morpholino ethanesulfonic acid (MEScapped photoluminescent gold nanoclusters (Au-MES NCs were investigated. The results showed that BSA-Au NCs accumulate in cells in a similar manner as BSA alone, indicating an endocytotic uptake mechanism while ultrasmall Au-MES NCs were distributed homogeneously throughout the whole cell volume including cell nucleus. The cytotoxicity of BSA-Au NCs was negligible, demonstrating good biocompatibility of such BSA-protected Au NCs. In contrast, possibly due to ultrasmall size and thin coating layer, Au-MES NCs exhibited exposure time-dependent high cytotoxicity and higher reactivity which led to highly increased generation of reactive oxygen species. The results demonstrate the importance of the coating layer to biocompatibility and toxicity of ultrasmall photoluminescent gold nanoclusters.

Target Glint Suppression Technology.

Science.gov (United States)

1980-09-01

Rayleigh for either horizontal or vertical polarization). 2.1.2 Spatial Characterization. Before the effects of diversity on target detection can be...ncs) dRCS T If the lower intergration limit is taken as zero for the Rayleigh targct model of interest, then this quantity is unbounded. In...port wing, inner section Trailing edge of starboard .:ing, inner section Leading edge of horizontal stabilizer, inner section, port side TLeal, -g

A dosimetry study comparing NCS report-5, IAEA TRS-381, AAPM TG-51 and IAEA TRS-398 in three clinical electron beam energies

International Nuclear Information System (INIS)

Palmans, Hugo; Nafaa, Laila; Patoul, Nathalie de; Denis, Jean-Marc; Tomsej, Milan; Vynckier, Stefaan

2003-01-01

New codes of practice for reference dosimetry in clinical high-energy photon and electron beams have been published recently, to replace the air kerma based codes of practice that have determined the dosimetry of these beams for the past twenty years. In the present work, we compared dosimetry based on the two most widespread absorbed dose based recommendations (AAPM TG-51 and IAEA TRS-398) with two air kerma based recommendations (NCS report-5 and IAEA TRS-381). Measurements were performed in three clinical electron beam energies using two NE2571-type cylindrical chambers, two Markus-type plane-parallel chambers and two NACP-02-type plane-parallel chambers. Dosimetry based on direct calibrations of all chambers in 60 Co was investigated, as well as dosimetry based on cross-calibrations of plane-parallel chambers against a cylindrical chamber in a high-energy electron beam. Furthermore, 60 Co perturbation factors for plane-parallel chambers were derived. It is shown that the use of 60 Co calibration factors could result in deviations of more than 2% for plane-parallel chambers between the old and new codes of practice, whereas the use of cross-calibration factors, which is the first recommendation in the new codes, reduces the differences to less than 0.8% for all situations investigated here. The results thus show that neither the chamber-to-chamber variations, nor the obtained absolute dose values are significantly altered by changing from air kerma based dosimetry to absorbed dose based dosimetry when using calibration factors obtained from the Laboratory for Standard Dosimetry, Ghent, Belgium. The values of the 60 Co perturbation factor for plane-parallel chambers (k att · k m for the air kerma based and p wall for the absorbed based codes of practice) that are obtained from comparing the results based on 60 Co calibrations and cross-calibrations are within the experimental uncertainties in agreement with the results from other investigators

77 FR 50138 - Submission for OMB Review; Comment Request: Collection of Customer Service, Demographic, and...

Science.gov (United States)

2012-08-20

...). Characterizing clients and how they found out about the CIS is essential to customer service, program planning...,123 Demographic 24,300 1 2/60 810 Questions. Smoking Cessation ``Quitline'' Clients: Reactive Service...

Partial characterization of chayotextle starch-based films added with ascorbic acid encapsulated in resistant starch.

Science.gov (United States)

Martínez-Ortiz, Miguel A; Vargas-Torres, Apolonio; Román-Gutiérrez, Alma D; Chavarría-Hernández, Norberto; Zamudio-Flores, Paul B; Meza-Nieto, Martín; Palma-Rodríguez, Heidi M

2017-05-01

Chayotextle starch was modified by subjecting it to a dual treatment with acid and heating-cooling cycles. This caused a decrease in the content of amylose, which showed values of 30.22%, 4.80%, 3.27% and 3.57% for native chayotextle starch (NCS), starch modified by acid hydrolysis (CMS), and CMS with one (CMS1AC) and three autoclave cycles (CMS3AC), respectively. The percentage of crystallinity showed an increase of 36.9%-62% for NCS and CMS3AC. The highest content of resistant starch (RS) was observed in CMS3AC (37.05%). The microcapsules were made with CMS3AC due to its higher RS content; the total content of ascorbic acid of the microcapsules was 82.3%. The addition of different concentrations of CMS3AC microcapsules (0%, 2.5%, 6.255% and 12.5%) to chayotextle starch-based films (CSF) increased their tensile strength and elastic modulus. The content of ascorbic acid and RS in CSF was ranged from 0% to 59.4% and from 4.84% to 37.05% in the control film and in the film mixed with CMS3AC microcapsules, respectively. Water vapor permeability (WVP) values decreased with increasing concentrations of microcapsules in the films. Microscopy observations showed that higher concentrations of microcapsules caused agglomerations due their poor distribution in the matrix of the films. Copyright © 2017 Elsevier B.V. All rights reserved.

Characterization of vehicular brake service personnel exposure to airborne asbestos and particulate.

Science.gov (United States)

Weir, F W; Tolar, G; Meraz, L B

2001-12-01

Evaluation of fibers and total particulate generated during the servicing of drum brakes on motor vehicles as well as during the resurfacing (arcing) of brake shoes was conducted. Conditions for the studies were based on review of contemporary (approximately 1950-1980) working practices in the industry. This work was conducted in two parts. Phase 1 estimated the release of asbestos fibers and total particulate during brake inspection and replacement of light-duty vehicle rear drum brakes at an auto/truck repair facility. Two distinct work practices were evaluated: One rear wheel from each vehicle was serviced using compressed air to remove dust while the second rear wheel was serviced without compressed air. Area and personal monitoring of fiber levels demonstrated counts (without compressed air) that ranged from 0.05 to 0.2 f/cc. Fiber counts when using compressed air averaged from 0.05 to 0.9 f/cc. Results from real-time aerosol monitoring indicated elevated dust levels for about 15 minutes after blow out. With shop doors open, dust levels increased to 5.0 mg/m3 at blow out and returned to 0.08 mg/m3 within two minutes. When the shop doors were closed, the dust levels reached 13.5 mg/m3 at blow out and decreased to 1.68 mg/m3 within one minute and to background within 14 minutes. The Phase 2 series evaluated the release of fibers and other particulate from are grinding. For operations conducted under conditions simulating a workplace, a mean of 0.19 f/cc +/- 0.16 was determined. Dust levels averaged 0.25 mg/m3 +/- 0.05. Brake service monitoring in these tests demonstrates that asbestos fiber concentrations, considered on a time weighted average basis, should not exceed currently acceptable workplace standards whether or not the worker uses compressed air, nor during the arc grinding process when arcing is conducted in accord with the design of the equipment.

Detection of nearest neighbors to specific fluorescently tagged ligands in rod outer segment and lymphocyte plasma membranes by photosensitization of 5-iodonaphthyl 1-azide

International Nuclear Information System (INIS)

Raviv, Y.; Bercovici, T.; Gitler, C.; Salomon, Y.

1989-01-01

Lima bean agglutinin-fluorescein 5-isothiocyanate conjugate (FluNCS-lima bean lectin) interacts with specific receptor molecules on membranes both from the rod outer segment (ROS) of the frog retina and from S49 mouse lymphoma cells. When [125I]-5-iodonaphthyl 1-azide (125I-INA), which freely and randomly partitions into the lipid bilayer, is added to membranes and the suspension is irradiated at 480 nm, the FluNCS-conjugated lectin photosensitizes the [125I]INA but only at discrete sites. This results in the selective labeling of specific proteins: an 88-kDa protein on ROS membranes and a 56-kDa protein on S49 plasma membranes. Labeling is dependent upon the interaction of the FluNCS-lectin with glycosylated receptor sites, since N-acetylgalactosamine, but not methyl alpha-mannoside, blocked labeling of the 56-kDa protein on S49 membranes. In contrast, a random labeling pattern of membrane proteins was observed upon irradiation at 480 nm using other fluorescein conjugates, such as FluNCS-bovine serum albumin (FluNCS-BSA) or FluNCS-soybean trypsin inhibitor (FluNCS-STI), which interact with cell membranes in a nonselective manner, or with N-(fluorescein-5-thiocarbamoyl)-n-undecyclamine (FluNCS-NHC11), which is freely miscible in the membrane lipid. Random labeling was also obtained by direct photoexcitation of [125I]INA at 314 nm, with no distinct labeling of the 88- and 56-kDa proteins in the respective membranes. These results suggest that protein ligands can be used to guide sensitizers to discrete receptor sites and lead to their selective labeling by photosensitized activation of [125I]INA

Dielectric enhancement of BaTiO3/SrTiO3 superlattices with embedded Ni nanocrystals

International Nuclear Information System (INIS)

Xiong Zhengwei; Sun Weiguo; Wang Xuemin; Jiang Fan; Wu Weidong

2012-01-01

Highlights: ► The BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs were successfully fabricated by L-MBE. ► The influence with the various concentrations of Ni nanocrystals embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. ► The BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss compared with the pure BaTiO 3 /SrTiO 3 superlattices. ► The dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory. - Abstract: The self-organized Ni nanocrystals (NCs) were embedded in BaTiO 3 /SrTiO 3 superlattices using laser molecular beam epitaxy (L-MBE). The stress of the composite films was increased with the increasing concentration of embedded Ni NCs, as investigation in stress calculation. The influence with the various concentrations of Ni NCs embedded in BaTiO 3 /SrTiO 3 superlattices was also discussed. The internal stress of the films was too strong to epitaxial growth of BaTiO 3 /SrTiO 3 superlattices. Compared with the pure BaTiO 3 /SrTiO 3 superlattices, the BaTiO 3 /SrTiO 3 superlattices with lower concentration of embedded Ni NCs had higher permittivity and dielectric loss. Furthermore, the dielectric enhancement of BaTiO 3 /SrTiO 3 superlattices with embedded Ni NCs was proposed to explained by Drude quasi-free-electron theory.

Highly Sensitive Sensors Based on Metal-Oxide Nanocolumns for Fire Detection

Directory of Open Access Journals (Sweden)

Kwangjae Lee

2017-02-01

Full Text Available A fire detector is the most important component in a fire alarm system. Herein, we present the feasibility of a highly sensitive and rapid response gas sensor based on metal oxides as a high performance fire detector. The glancing angle deposition (GLAD technique is used to make the highly porous structure such as nanocolumns (NCs of various metal oxides for enhancing the gas-sensing performance. To measure the fire detection, the interface circuitry for our sensors (NiO, SnO2, WO3 and In2O3 NCs is designed. When all the sensors with various metal-oxide NCs are exposed to fire environment, they entirely react with the target gases emitted from Poly(vinyl chlorides (PVC decomposed at high temperature. Before the emission of smoke from the PVC (a hot-plate temperature of 200 °C, the resistances of the metal-oxide NCs are abruptly changed and SnO2 NCs show the highest response of 2.1. However, a commercial smoke detector did not inform any warning. Interestingly, although the NiO NCs are a p-type semiconductor, they show the highest response of 577.1 after the emission of smoke from the PVC (a hot-plate temperature of 350 °C. The response time of SnO2 NCs is much faster than that of a commercial smoke detector at the hot-plate temperature of 350 °C. In addition, we investigated the selectivity of our sensors by analyzing the responses of all sensors. Our results show the high potential of a gas sensor based on metal-oxide NCs for early fire detection.

Electrophoretic mobility shift in native gels indicates calcium-dependent structural changes of neuronal calcium sensor proteins.

Science.gov (United States)

Viviano, Jeffrey; Krishnan, Anuradha; Wu, Hao; Venkataraman, Venkat

2016-02-01

In proteins of the neuronal calcium sensor (NCS) family, changes in structure as well as function are brought about by the binding of calcium. In this article, we demonstrate that these structural changes, solely due to calcium binding, can be assessed through electrophoresis in native gels. The results demonstrate that the NCS proteins undergo ligand-dependent conformational changes that are detectable in native gels as a gradual decrease in mobility with increasing calcium but not other tested divalent cations such as magnesium, strontium, and barium. Surprisingly, such a gradual change over the entire tested range is exhibited only by the NCS proteins but not by other tested calcium-binding proteins such as calmodulin and S100B, indicating that the change in mobility may be linked to a unique NCS family feature--the calcium-myristoyl switch. Even within the NCS family, the changes in mobility are characteristic of the protein, indicating that the technique is sensitive to the individual features of the protein. Thus, electrophoretic mobility on native gels provides a simple and elegant method to investigate calcium (small ligand)-induced structural changes at least in the superfamily of NCS proteins. Copyright © 2015 Elsevier Inc. All rights reserved.

Ab initio study on the effect of structural relaxation on the electronic and optical properties of P-doped Si nanocrystals

International Nuclear Information System (INIS)

Pi, Xiaodong; Ni, Zhenyi; Yang, Deren; Delerue, Christophe

2014-01-01

In contrast to the conventional doping of bulk silicon (Si), the doping of Si nanocrystals (NCs) that are often smaller than 5 nm in diameter may lead to serious structural changes. Since the electronic and optical properties of Si NCs are intimately associated with their structures, it is critical to understand how doping impacts the structures of Si NCs. By means of ab initio calculation we now compare 1.4 nm phosphorus (P)-doped Si NCs without structural relaxation and those with structural relaxation. Structural changes induced by structural relaxation are manifested by the stretching and compressing of bonds and apparent variations in bond angles. With the increase of the concentration of P structural changes induced by structural relaxation become more serious. It is found that structural relaxation makes differences in the energy-level schemes of P-doped Si NCs. Structural relaxation also causes the binding energy of an electron in a P-doped Si NC to more significantly increase as the concentration of P increases. With the increase of the concentration of P structural relaxation leads to more pronounced changes in the optical absorption of P-doped Si NCs

Oligonucleotide-stabilized fluorescent silver nanoclusters for the specific and sensitive detection of biotin.

Science.gov (United States)

Xiong, Xiaoli; Tang, Yan; Zhao, Jingjin; Zhao, Shulin

2016-02-21

A novel biotin fluorescent probe based on oligonucleotide-stabilized silver nanoclusters (DNA-AgNCs) was synthesized by employing a biotinylated cytosine-rich sequence as a synthesized template. The fluorescence properties of the DNA-AgNCs are related to the modified position of the DNA. When biotin is linked to the middle thymine base of the DNA sequence, the DNA-AgNCs emit the strongest fluorescence. Moreover, the stability of the DNA-AgNCs was affected by avidin through biotin-avidin binding, quenching the fluorescence of the DNA-AgNCs. In contrast, if free biotin is further introduced into this system, the quenching is apparently weakened by competition, leading to the restoration of fluorescence. This phenomenon can be utilized for the detection of biotin. Under the optimal conditions, the fluorescence recovery is linearly proportional to the concentration of biotin in the range of 10 nM-1.0 μM with a detection limit of 6.0 nM. This DNA-AgNCs probe with excellent fluorescent properties is sensitive and selective for the detection of biotin and has been applied for the determination of biotin in wheat flour.

Design and mechanistic study of a novel gold nanocluster-based drug delivery system.

Science.gov (United States)

Li, Qinzhen; Pan, Yiting; Chen, Tiankai; Du, Yuanxin; Ge, Honghua; Zhang, Buchang; Xie, Jianping; Yu, Haizhu; Zhu, Manzhou

2018-05-22

Chemically-triggered drug delivery systems (DDSs) have been extensively studied as they do not require specialized equipment to deliver the drug and can deeply penetrate human tissue. However, their syntheses are complicated and they tend to be cytotoxic, which restricts their clinical utility. In this work, the self-regulated drug loading and release capabilities of peptide-protected gold nanoclusters (Pep-Au NCs) are investigated using vancomycin (Van) as the model drug. Gold nanoclusters (Au NCs) coated with a custom-designed pentapeptide are synthesized as drug delivery nanocarriers and loaded with Van - a spontaneous process reliant on the specific binding between Van and the custom-designed peptide. The Van-loaded Au NCs show comparable antimicrobial activity with Van on its own, and the number of Van released by the Pep-Au NCs is found to be proportional to the amount of bacteria present. The controlled nature of the Van release is very encouraging, and predominantly due to the stronger binding affinity of Van with bacteria than that with Au NCs. In addition, these fluorescent Au NCs could also be used to construct temperature sensors, which enable the in vitro and in vivo bioimaging.

Hydrological characterization of the Usumacinta River Basin towards the preservation of environmental services

Science.gov (United States)

Tapia-Silva, F.-O.; Contreras-Silva, A.-I.; Rosales-Arriaga, E.-R.

2015-04-01

The Usumacinta basin is characterized by aboundance of natural and scenic resources. It also houses a vast biodiversity (wich also means invaluable genetic resources). Its river is the longest in Mexico (main channel length of 927 km). Therefore it is one of the most productive regions of the country in terms of ecosystem services (such as habitat for biodiversity, maintenance of wetlands, water flows generation, carbon sequestration, soil retention, etc.) that are directly related to the hydrological functioning. During the last centuries, human activities on the Usumacinta basin have drastically changed its geomorphology and vegetation cover. As a result the hydrological cycle has been greatly modified. Therefore, it is necessary to conduct studies in order to support planning activities and implementation of public policies, as well as, to generate a permanent scientific ecosystem monitoring system. This paper presents the results of a study focused on estimating the water balance of this frontier basin. Satellite and field data is used. Variables as vegetation cover (generated by classification of Landsat and MODIS), digital terrain model (SRTM), surface temperature (MODIS), potential evaporation, precipitation and runoff measurements were processed. Various techniques of Remote Sensing, geospatial models (as SSEB and the model for definition of surface hydrological connectivity) and spatial analysis (geostatistics and map algebra) were implemented. The results were integrated into the environment of a Geographic Information System. These are estimates of actual evapotranspiration, soil moisture and runoff, among other biophysical parameters. For the lower part of the basin a balance was performed to estimate inputs of water from runoff and precipitation to the large amount of wetlands in the area. Additionally, areas generating runoff and areas in which most of the precipitaion infiltrates were also mapped. The geo-information obtained is requiered for

TEACHER TRAINING IN COMMUNITIES OF PRACTICE: THE CASE OF A GROUP OF PRE-SERVICE CHEMISTRY TEACHERS

OpenAIRE

Santos, Valéria C.; Arroio, Agnaldo

2015-01-01

This work deals with communities of practice and their contribution to pre-service teacher training. A group of eight pre-service chemistry teachers was accompanied during their participation in the PIBID program. Based on their interaction in planning teaching activities, the group was characterized as a community of practice. For this characterization the three dimensions of communities of practice were observed: mutual engagement, joint enterprise and shared repertoire. The results showed ...

Accelerating the peroxidase-like activity of gold nanoclusters at neutral pH for colorimetric detection of heparin and heparinase activity.

Science.gov (United States)

Hu, Lianzhe; Liao, Hong; Feng, Lingyan; Wang, Min; Fu, Wensheng

2018-04-26

The peroxidase-like catalytic activity of gold nanoclusters (NCs) is quite low around physiological pH, which greatly limits their biological applications. Herein, we found heparin can greatly accelerate the peroxidase-like activity of Au-NCs at neutral pH. The catalytic activity of Au-NCs toward the peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) oxidation by H2O2 was 25-fold increased in the presence of heparin at pH 7. The addition of heparin not only accelerated the initial catalytic rate of Au-NCs, but also prevented the Au-NCs from catalyst deactivation. This allows the sensitive colorimetric detection of heparin at neutral pH. In the presence of heparinase, heparin was hydrolyzed into small fragments, weakening the enhancement effect of catalytic activity. Based on this phenomenon, the sensitive colorimetric determination of heparinase in biological samples was also developed.

Facile Phosphine-Free Synthesis of CdSe/ZnS Core/Shell Nanocrystals Without Precursor Injection

Directory of Open Access Journals (Sweden)

Zhu Chang-Qing

2008-01-01

Full Text Available AbstractA new simple method for synthesis of core/shell CdSe/ZnS nanocrystals (NCs is present. By adapting the use of cadmium stearate, oleylamine, and paraffin liquid to a non-injection synthesis and by applying a subsequent ZnS shelling procedure to CdSe NCs cores using Zinc acetate dihydrate and sulfur powder, luminescent CdSe/ZnS NCs with quantum yields of up to 36% (FWHM 42–43 nm were obtained. A seeding-growth technique was first applied to the controlled synthesis of ZnS shell. This method has several attractive features, such as the usage of low-cost, green, and environmentally friendlier reagents and elimination of the need for air-sensitive, toxic, and expensive phosphines solvent. Furthermore, due to one-pot synthetic route for CdSe/ZnS NCs, the approach presented herein is accessible to a mass production of these NCs.

Fluorescent turn-on determination of the activity of peptidases using peptide templated gold nanoclusters

International Nuclear Information System (INIS)

Luo, Junjun; Wang, Liqiang; Zeng, Ke; Shen, Congcong; Qian, Pin; Yang, Minghui; Rasooly, Avraham; Qu, Fengli

2016-01-01

The fluorescence intensity of gold nanoclusters (AuNCs) is inversely related to the length of a peptide immobilized on its surface. This finding has been exploited to design a turn-on fluorescent method for the determination of the activity of peptidase. The β-site amyloid precursor protein-cleaving enzyme 1 (BACE1) was chosen as a model peptidase. BACE1 cleaves the peptide substrates on AuNCs, and the fluorescence intensity of the AuNCs (at exCitation/emission wavelengths of 320/405 nm) carrying the rest of the cleaved peptide is significantly higher than that of the AuNCs with uncleaved peptide. Transmission electron microscopy revealed a decrease in the size of the AuNCs which is assumed cause fluorescence enhancement. The assay was applied to the determination of BACE1 activity in spiked cell lysates, and recoveries were between 96.9 and 104.0 %. (author)

AVTA Federal Fleet PEV Readiness Data Logging and Characterization Study for the National Park Service: Fort Vancouver National Historic Site

Energy Technology Data Exchange (ETDEWEB)

Stephen Schey; Jim Francfort

2014-03-01

Battelle Energy Alliance, LLC, managing and operating contractor for the U.S. Department of Energy’s Idaho National Laboratory, is the lead laboratory for the U.S. Department of Energy’s Advanced Vehicle Testing. Battelle Energy Alliance, LLC contracted with Intertek Testing Services, North America (ITSNA) to collect data on federal fleet operations as part of the Advanced Vehicle Testing Activity’s Federal Fleet Vehicle Data Logging and Characterization study. The Advanced Vehicle Testing Activity study seeks to collect data to validate the use of advanced electric drive vehicle transportation. This report focuses on the Fort Vancouver National Historic Site (FVNHS) fleet to identify daily operational characteristics of select vehicles and report findings on vehicle and mission characterizations to support the successful introduction of electric vehicles (EVs) into the agencies’ fleet. Individual observations of the selected vehicles provided the basis for recommendations related to EV adoption and whether a battery electric vehicle (BEV) or plug-in hybrid electric vehicle (PHEV) (collectively plug-in electric vehicles) could fulfill the mission requirements. FVNHS identified three vehicles in its fleet for consideration. While the FVNHS vehicles conduct many different missions, only two (i.e., support and pool missions) were selected by agency management to be part of this fleet evaluation. The logged vehicles included a pickup truck and a minivan. This report will show that BEVs and PHEVs are capable of performing the required missions and providing an alternative vehicle for both mission categories, because each has sufficient range for individual trips and time available each day for charging to accommodate multiple trips per day. These charging events could occur at the vehicle’s home base, high-use work areas, or in intermediate areas along routes that the vehicles frequently travel. Replacement of vehicles in the current fleet would result in

In vitro and in vivo evaluation of SN-38 nanocrystals with different particle sizes

Directory of Open Access Journals (Sweden)

Chen M

2017-08-01

Full Text Available Min Chen,1,2 Wanqing Li,3 Xun Zhang,1 Ye Dong,1 Yabing Hua,1 Hui Zhang,1 Jing Gao,1 Liang Zhao,2 Ying Li,1 Aiping Zheng1 1State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Institute of Pharmacology and Toxicology, 2School of Pharmacy, Jinzhou Medical University, Jinzhou, 3School of Preclinical Medicine, Beijing University of Chinese Medicine, Beijing, People’s Republic of China Abstract: 7-Ethyl-10-hydroxycamptothecin (SN-38 is a potent broad-spectrum antitumor drug derived from irinotecan hydrochloride (CPT-11. Due to its poor solubility and instability of the active lactone ring, its clinical use is significantly limited. As one of the most promising formulations for poorly water-soluble drugs, nanocrystals have attracted increasing attention. In order to solve these problems and evaluate the antitumor effect of SN-38 in vitro and in vivo, two nanocrystals with markedly different particle sizes were prepared. Dynamic light scattering and transmission electron microscopy were used to investigate the two nanocrystals. The particle sizes of SN-38 nanocrystals A (SN-38/NCs-A and SN-38 nanocrystals B (SN-38/NCs-B were 229.5±1.99 and 799.2±14.44 nm, respectively. X-ray powder diffraction analysis showed that the crystalline state of SN-38 did not change in the size reduction process. An accelerated dissolution velocity of SN-38 was achieved by nanocrystals, and release rate of SN-38/NCs-A was significantly faster than that of SN-38/NCs-B. Cellular uptake, cellular cytotoxicity, pharmacokinetics, animal antitumor efficacy, and tissue distribution were subsequently examined. As a result, enhanced intracellular accumulation in HT1080 cells and cytotoxicity on different tumor cells were observed for SN-38/NCs-A compared to that for SN-38/NCs-B and solution. Besides, compared to the SN-38 solution, SN-38/NCs-A had a higher bioavailability after intravenous injection; while the bioavailability of SN-38/NCs-B was even lower than

Improving Climate Literacy of NOAA Staff and Users

Science.gov (United States)

Timofeyeva, M. M.; Bair, A.; Staudenmaier, M.; Meyers, J. C.; Mayes, B.; Zdrojewski, J.

2010-12-01

Since 2002, NOAA’s National Weather Service (NWS) Climate Services Division (CSD) has offered numerous training opportunities to NWS staff. After eight-years of development, the training program offers three instructor-led courses and roughly 25 online (distance learning) modules covering various climate topics, such as: climate data and observations, climate variability and change, and NWS national / local climate products (tools, skill, and interpretation). Leveraging climate information and expertise available at all NOAA line offices and partners allows for the delivery of the most advanced knowledge and is a very critical aspect of the training program. The emerging NOAA Climate Service (NCS) requires a well-trained, climate-literate workforce at the local level capable of delivering NOAA’s climate products and services as well as providing climate-sensitive decision support. NWS Weather Forecast Offices and River Forecast Centers presently serve as local outlets for the NCS climate services. Trained NWS climate service personnel use proactive and reactive approaches and professional education methods in communicating climate variability and change information to local users. Both scientifically-sound messages and amiable communication techniques are important in developing an engaged dialog between the climate service providers and users. Several pilot projects have been conducted by the NWS CSD this past year that apply the program’s training lessons and expertise to specialized external user group training. The technical user groups included natural resources managers, engineers, hydrologists, and planners for transportation infrastructure. Training of professional user groups required tailoring instructions to the potential applications for each group of users. Training technical users identified the following critical issues: (1) knowledge of target audience expectations, initial knowledge status, and potential use of climate information; (2

Nuclear criticality safety program at the University of Tennessee-Knoxville

International Nuclear Information System (INIS)

Basoglu, B.; Bentley, C.; Brewer, R.; Dunn, M.; Haught, C.; Plaster, M.; Wilkinson, A.; Dodds, H.; Elliott, E.; Waddell, W.

1993-01-01

This paper presents an overview of the nuclear criticality safety (NCS) educational program at the University of Tennessee-Knoxville. The program is an academic specialization for nuclear engineering graduate students pursuing either the MS or PhD degree and includes special NCS courses and NCS research projects. Both the courses and the research projects serve as partial fulfillment of the requirements for the degree being pursued

Modifying the size and uniformity of upconversion Yb/Er:NaGdF4 nanocrystals through alkaline-earth doping.

Science.gov (United States)

Lei, Lei; Chen, Daqin; Huang, Ping; Xu, Ju; Zhang, Rui; Wang, Yuansheng

2013-11-21

NaGdF4 is regarded as an ideal upconversion (UC) host material for lanthanide (Ln(3+)) activators because of its unique crystal structure, high Ln(3+) solubility, low phonon energy and high photochemical stability, and Ln(3+)-doped NaGdF4 UC nanocrystals (NCs) have been widely investigated as bio-imaging and magnetic resonance imaging agents recently. To realize their practical applications, controlling the size and uniformity of the monodisperse Ln(3+)-doped NaGdF4 UC NCs is highly desired. Unlike the routine routes by finely adjusting the multiple experimental parameters, herein we provide a facile and straightforward strategy to modify the size and uniformity of NaGdF4 NCs via alkaline-earth doping for the first time. With the increase of alkaline-earth doping content, the size of NaGdF4 NCs increases gradually, while the size-uniformity is still retained. We attribute this "focusing" of size distribution to the diffusion controlled growth of NaGdF4 NCs induced by alkaline-earth doping. Importantly, adopting the Ca(2+)-doped Yb/Er:NaGdF4 NCs as cores, the complete Ca/Yb/Er:NaGdF4@NaYF4 core-shell particles with excellent size-uniformity can be easily achieved. However, when taking the Yb/Er:NaGdF4 NCs without Ca(2+) doping as cores, they could not be perfectly covered by NaYF4 shells, and the obtained products are non-uniform in size. As a result, the UC emission intensity of the complete core-shell NCs increases by about 30 times in comparison with that of the cores, owing to the effective surface passivation of the Ca(2+)-doped cores and therefore protection of Er(3+) in the cores from the non-radiative decay caused by surface defects, whereas the UC intensity of the incomplete core-shell NCs is enhanced by only 3 times.

Multinational enterprises, service outsourcing and regional structural change

NARCIS (Netherlands)

Ascani, A.; Iammarino, Simona

2017-01-01

This paper offers a joint analysis of two phenomena characterizing most advanced economies in recent decades: the rise of foreign ownership in manufacturing activities and the pervasiveness of the service economy. The aim of the study is to examine the structural transformation of regional economic

Characterization report for Buildings 3706 and 37006A

International Nuclear Information System (INIS)

Smith, D.S.

1997-06-01

The 3706 and 3706A Buildings were originally constructed to perform small-scale experiments in support of all Hanford Engineering Works production activities. The primary focus was to perform radiochemical trials aimed at improving the bismuth phosphate process. The facility housed 19 offices, 2 shops, a dark room, 2 storerooms, a lunchroom, locker room, ventilating equipment room, sanitary restrooms, and 57 laboratories, including a special laboratory with 0.6-m-(2-ft) thick concrete walls reserved for the hottest analytical work. The 3706 Building was decontaminated and remodeled in 1954 and 1955, and many of the laboratories were converted to offices at that time. By 1964, the facility was called the General Services Building, and although it still contained some analytical laboratories, the majority of the space was devoted to mail, duplicating, photographic, and drafting services; a first aid station, and the 300 Area Hanford Patrol headquarters. All laboratory work was eventually phased out by the end of the 1980's. The primary objective of the characterization activities described in this report is to properly designate the building debris waste in preparation for demolition of the building and disposal at the Environmental Restoration Disposal Facility Waste. The scope of services for this characterization project included the following tasks: historical records review; facility inspection; radiological surveys; data quality objective; sampling and analysis instruction; field sampling and laboratory analysis; preparation of this characterization report

A High Molar Extinction Coefficient Ru(II Complex Functionalized with cis-Dithiocyanato-bis-(9-anthracenyl-10-(2-methyl-2-butenoic acid-1,10-phenanthroline: Potential Sensitizer for Stable Dye-Sensitized Solar Cells

Directory of Open Access Journals (Sweden)

Adewale O. Adeloye

2014-01-01

Full Text Available New heteroleptic ruthenium(II complex was formulated as [Ru(L12(NCS2], where L1 = 9-anthracenyl-10-(2-methyl-2-butenoic acid-1,10-phenanthroline was synthesized and its photophysical properties were studied and compared to previously reported analogue complex containing no anthracene moiety [Ru(L22(NCS2], L2 = (2-methyl-2-butenoic acid-1,10-phenanthroline. The two complexes though exhibit very strong molar extinction coefficient values; however, [Ru(L12(NCS2] shows better characteristic broad and intense metal-to-ligand charge transfer (MLCT absorption band and higher molar absorptivity coefficient at (λmax=522 nm, ε=6.60×104 M−1 cm−1 than that of [Ru(L22(NCS2] complex, (λmax=446 nm, ε=4.82×104 M−1 cm−1. At room temperature, long wavelength emissions with strong intensity ratio centered at 660 nm were recorded for [Ru(L12(NCS2] complex with a bathochromic shift (λem=700 nm for [Ru(L22(NCS2] complex. It was shown that the luminescence wavelength characteristic of the complexes may be a function relating to the increasing length of π-conjugation and/or molecular weight. A preliminary cyclic voltammetry of [Ru(L12(NCS2] complex also exhibits good electroredox activity with oxidation potential of about 1.04 V, significantly better than other Ru(II polypyridine complexes containing bidentate ligands.

Magneto-optical properties of α-Fe2O3@ZnO nanocomposites prepared by the high energy ball-milling technique

Science.gov (United States)

Chaudhury, Chandana Roy; Roychowdhury, Anirban; Das, Anusree; Das, Dipankar

2016-05-01

Magnetic-fluorescent nanocomposites (NCs) with 10 wt% of α-Fe2O3 in ZnO have been prepared by the high energy ball-milling. The crystallite sizes of α-Fe2O3 and ZnO in the NCs are found to vary from 65 nm to 20 nm and 47 nm to 15 nm respectively as milling time is increased from 2 to 30 h. XRD analysis confirms presence of α-Fe2O3 and ZnO in pure form in all the NCs. UV-vis study of the NCs shows a continuous blue-shift of the absorption peak and a steady increase of band gap of ZnO with increasing milling duration that are assigned to decreasing particle size of ZnO in the NCs. Photoluminescence (PL) spectra of the NCs reveal three weak emission bands in the visible region at 421, 445 and 485 nm along with the strong near band edge emission at 391 nm. These weak emission bands are attributed to different defect - related energy levels e.g. Zn-vacancy, Zn interstitial and oxygen vacancy. Dc and ac magnetization measurements show presence of weakly interacting superparamagnetic (SPM) α-Fe2O3 particles in the NCs. 57Fe-Mössbauer study confirms presence of SPM hematite in the sample milled for 30 h. Positron annihilation lifetime measurements indicate presence of cation vacancies in ZnO nanostructures confirming results of PL studies.