Effectiveness of the Picture Exchange Communication System as a Functional Communication Intervention for Individuals with Autism Spectrum Disorders: A Practice-Based Research Synthesis

ERIC Educational Resources Information Center

Tien, Kai-Chien

2008-01-01

This research synthesis verifies the effectiveness of the Picture Exchange Communication System (PECS) for improving the functional communication skills of individuals with autism spectrum disorders (ASD). The research synthesis was focused on the degree to which variations in PECS training are associated with variations in functional…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nurmikko, Arto V

Synthesis of semiconductor nanomaterials by low-cost, solution-based methods is shown to lead to new classes of thin film light emitting materials. These materials have been integrated to demonstrative compact laser device testbeds to illustrate their potential for coherent emitters across the visible spectrum to disrupt established photonics technologies, particularly semiconductor lasers?

Identification of a broad-spectrum inhibitor of virus RNA synthesis: validation of a prototype virus-based approach

PubMed Central

Filone, Claire Marie; Hodges, Erin N.; Honeyman, Brian; Bushkin, G. Guy; Boyd, Karla; Platt, Andrew; Ni, Feng; Strom, Kyle; Hensley, Lisa; Snyder, John K.; Connor, John H.

2013-01-01

There are no approved therapeutics for the most deadly nonsegmented negative-strand (NNS) RNA viruses, including Ebola (EBOV). To identify new chemical scaffolds for development of broad-spectrum antivirals, we undertook a prototype-based lead identification screen. Using the prototype NNS virus, vesicular stomatitis virus (VSV), multiple inhibitory compounds were identified. Three compounds were investigated for broad-spectrum activity, and inhibited EBOV infection. The most potent, CMLDBU3402, was selected for further study. CMLDBU3402 did not show significant activity against segmented negative-strand RNA viruses suggesting proscribed broad-spectrum activity. Mechanistic analysis indicated that CMLDBU3402 blocked VSV viral RNA synthesis and inhibited EBOV RNA transcription, demonstrating a consistent mechanism of action against genetically distinct viruses. The identification of this chemical backbone as a broad-spectrum inhibitor of viral RNA synthesis offers significant potential for the development of new therapies for highly pathogenic viruses. PMID:23521799

OPTICAL INFORMATION PROCESSING: Synthesis of an object recognition system based on the profile of the envelope of a laser pulse in pulsed lidars

NASA Astrophysics Data System (ADS)

Buryi, E. V.

1998-05-01

The main problems in the synthesis of an object recognition system, based on the principles of operation of neuron networks, are considered. Advantages are demonstrated of a hierarchical structure of the recognition algorithm. The use of reading of the amplitude spectrum of signals as information tags is justified and a method is developed for determination of the dimensionality of the tag space. Methods are suggested for ensuring the stability of object recognition in the optical range. It is concluded that it should be possible to recognise perspectives of complex objects.

Microwave-Assisted Synthesis Cd Metal Hexagonal Nanosheets

NASA Astrophysics Data System (ADS)

Sun, Yidong; She, Houde; Bai, Wencai; Li, Liangshan; Zhou, Hua

2018-07-01

Sodium borohydride (NaBH4) as reducing agent, oleic acid (OA) as surfactant, deionized water as the dispersant, reducing cadmium nitrate (Cd(NO3)2 · 4H2O) can get Cd nanosheets by microwave method. Room temperature photoluminescence (PL) spectrum for Cd nanosheets recorded under xenon light wavelength of 325 nm exhibited obviously emission bands at 331, 379, and 390 nm. By analyzing the results of XRD and TEM, the nanosheets are thought as hexagonal phase and the size is about 20 nm. This synthesis performs in a lower temperature. Moreover our method is quite simple and the cost of the experiment is relatively lower.

Precision of proportion estimation with binary compressed Raman spectrum.

PubMed

Réfrégier, Philippe; Scotté, Camille; de Aguiar, Hilton B; Rigneault, Hervé; Galland, Frédéric

2018-01-01

The precision of proportion estimation with binary filtering of a Raman spectrum mixture is analyzed when the number of binary filters is equal to the number of present species and when the measurements are corrupted with Poisson photon noise. It is shown that the Cramer-Rao bound provides a useful methodology to analyze the performance of such an approach, in particular when the binary filters are orthogonal. It is demonstrated that a simple linear mean square error estimation method is efficient (i.e., has a variance equal to the Cramer-Rao bound). Evolutions of the Cramer-Rao bound are analyzed when the measuring times are optimized or when the considered proportion for binary filter synthesis is not optimized. Two strategies for the appropriate choice of this considered proportion are also analyzed for the binary filter synthesis.

GrayStarServer: Server-side Spectrum Synthesis with a Browser-based Client-side User Interface

NASA Astrophysics Data System (ADS)

Short, C. Ian

2016-10-01

We present GrayStarServer (GSS), a stellar atmospheric modeling and spectrum synthesis code of pedagogical accuracy that is accessible in any web browser on commonplace computational devices and that runs on a timescale of a few seconds. The addition of spectrum synthesis annotated with line identifications extends the functionality and pedagogical applicability of GSS beyond that of its predecessor, GrayStar3 (GS3). The spectrum synthesis is based on a line list acquired from the NIST atomic spectra database, and the GSS post-processing and user interface client allows the user to inspect the plain text ASCII version of the line list, as well as to apply macroscopic broadening. Unlike GS3, GSS carries out the physical modeling on the server side in Java, and communicates with the JavaScript and HTML client via an asynchronous HTTP request. We also describe other improvements beyond GS3 such as a more physical treatment of background opacity and atmospheric physics, the comparison of key results with those of the Phoenix code, and the use of the HTML < {canvas}> element for higher quality plotting and rendering of results. We also present LineListServer, a Java code for converting custom ASCII line lists in NIST format to the byte data type file format required by GSS so that users can prepare their own custom line lists. We propose a standard for marking up and packaging model atmosphere and spectrum synthesis output for data transmission and storage that will facilitate a web-based approach to stellar atmospheric modeling and spectrum synthesis. We describe some pedagogical demonstrations and exercises enabled by easily accessible, on-demand, responsive spectrum synthesis. GSS may serve as a research support tool by providing quick spectroscopic reconnaissance. GSS may be found at www.ap.smu.ca/~ishort/OpenStars/GrayStarServer/grayStarServer.html, and source tarballs for local installations of both GSS and LineListServer may be found at www.ap.smu.ca/~ishort/OpenStars/.

Optimization of Synthesis Conditions of Carbon Nanotubes via Ultrasonic-Assisted Floating Catalyst Deposition Using Response Surface Methodology

PubMed Central

Mohammadian, Narges; Ghoreishi, Seyyed M.; Hafeziyeh, Samira; Saeidi, Samrand; Dionysiou, Dionysios D.

2018-01-01

The growing use of carbon nanotubes (CNTs) in a plethora of applications has provided to us a motivation to investigate CNT synthesis by new methods. In this study, ultrasonic-assisted chemical vapor deposition (CVD) method was employed to synthesize CNTs. The difficulty of controlling the size of clusters and achieving uniform distribution—the major problem in previous methods—was solved by using ultrasonic bath and dissolving ferrocene in xylene outside the reactor. The operating conditions were optimized using a rotatable central composite design (CCD), which helped optimize the operating conditions of the method. Response surface methodology (RSM) was used to analyze these experiments. Using statistical software was very effective, considering that it decreased the number of experiments needed to achieve the optimum conditions. Synthesis of CNTs was studied as a function of three independent parameters viz. hydrogen flow rate (120–280 cm3/min), catalyst concentration (2–6 wt %), and synthesis temperature (800–1200 °C). Optimum conditions for the synthesis of CNTs were found to be 3.78 wt %, 184 cm3/min, and 976 °C for catalyst concentration, hydrogen flow rate, and synthesis temperature, respectively. Under these conditions, Raman spectrum indicates high values of (IG/ID), which means high-quality CNTs. PMID:29747451

Synthesis of carbon nanomaterials from different pyrolysis techniques: a review

NASA Astrophysics Data System (ADS)

Umer Zahid, Muhammad; Pervaiz, Erum; Hussain, Arshad; Shahzad, Muhammad Imran; Niazi, Muhammad Bilal Khan

2018-05-01

In the current age, the significance of carbon-based nanomaterials for many applications has made the efforts for the facile synthesis methods from abundantly available wastes in a cost-effective way. Pyrolysis in a broad spectrum is commonly employed for the synthesis of carbon nanostructures by thermally treating the organic waste. The mechanism of growth of the nanoparticles determines the functional distribution of nanoparticles based on the growing size, medium, and physio-chemical properties. Carbon nanomaterial’s growth is a complicated process which is profoundly influenced by temperature, catalyst, and type of precursor. Nowadays, significant progress has been made in improving nanomaterial’s growth techniques, opening new paths for commercial production of carbon-based nanomaterials. The most promising are the methods involving hydrocarbon-rich organic waste as the feed source. In this review, synthesis of carbon-based nanomaterials, specifically carbon nanotubes (CNTs), Carbon nanofibers (CNFs) and Graphene (G) are discussed by different pyrolysis techniques. Furthermore, the review explores recent advancements made in the context of pyrolysis.

Stellar Populations in BL Lac type Objects

NASA Astrophysics Data System (ADS)

Serote Roos, Margarida

The relationship between an Active Galactic Nucleus (AGN) and its host galaxy is a crucial question in the study of galaxy evolution. We present an estimate of the stellar contribution in a sample of low luminosity BL Lac type objects. We have performed stellar population synthesis for a sample of 19 objects selected from Marchã et al. (1996, MNRAS 281, 425). The stellar content is quantified using the equivalent widths of all absorption features available throughout the spectrum. The synthesis is done by a variant of the GPG method (Pelat: 1997, MNRAS 284, 365).

Fabrication of highly efficient ZnO nanoscintillators

NASA Astrophysics Data System (ADS)

Procházková, Lenka; Gbur, Tomáš; Čuba, Václav; Jarý, Vítězslav; Nikl, Martin

2015-09-01

Photo-induced synthesis of high-efficiency ultrafast nanoparticle scintillators of ZnO was demonstrated. Controlled doping with Ga(III) and La(III) ions together with the optimized method of ZnO synthesis and subsequent two-step annealing in air and under reducing atmosphere allow to achieve very high intensity of UV exciton luminescence, up to 750% of BGO intensity magnitude. Fabricated nanoparticles feature extremely short sub-nanosecond photoluminescence decay times. Temperature dependence of the photoluminescence spectrum within 8-340 K range was investigated and shows the absence of visible defect-related emission within all temperature intervals.

Synthesis and surface activity properties of alkylphenol polyoxyethylene nonionic trimeric surfactants

NASA Astrophysics Data System (ADS)

Yang, Fang; Li, Gang; Qi, Jian; Zhang, Song-Mei; Liu, Rong

2010-10-01

A series of trimeric n-alkylphenol polyoxyethylene surfactants (TAP) were successfully synthesized and the molecular structure were confirmed by NMR, FTIR spectrum and elemental analysis. Using the same synthesis route, the trimeric nonylphenol polyoxyethylene surfactant (TNP) was synthesized using industrial product nonylphenol and paraformaldehyde, and its molecular structure was characterized by 1HNMR, FTIR spectrum and elemental analysis. The optimal reaction conditions were established. The surface activity properties of TAP and TNP (such as the critical micelle concentration (cmc), the values of surface tension at the cmc ( γcmc), the maximum surface excess concentration ( Γcmc), and the minimum surface area per surfactant molecule ( Acmc)), were determined by means of Wilhelmy plate method and steady-state fluorescence probe method, respectively. The experimental results show that the lengths of the hydrophilic group oxyethylene (EO) chains and hydrophobic group methylene chains have an influence on the cmc, γcmc, Γcmc, and Acmc of series of surfactants. Furthermore, TAP are arranged to staggered three-dimensional array mode at the air-water interface, which has exhibited better surface properties, such as low cmc values, strong adsorption affinities and wet abilities.

Lived Experiences from the Perspective of Individuals with Autism Spectrum Disorder: A Qualitative Meta-Synthesis

ERIC Educational Resources Information Center

DePape, Anne-Marie; Lindsay, Sally

2016-01-01

Autism spectrum disorder (ASD) includes deficits in social communication and repetitive behavior. Secondhand accounts from parents suggest that ASD affects many aspects of life. However, little is known about this disorder from first-person perspective. This meta-synthesis examines children, adolescents, and adults with ASD to understand their…

Asymmetric Synthesis of (R)-1-Alkyl Substituted Tetrahydro-ß-carbolines Catalyzed by Strictosidine Synthases.

PubMed

Pressnitz, Desiree; Fischereder, Eva-Maria; Pletz, Jakob; Kofler, Christina; Hammerer, Lucas; Hiebler, Katharina; Lechner, Horst; Richter, Nina; Eger, Elisabeth; Kroutil, Wolfgang

2018-05-31

Stereoselective methods for the synthesis of tetrahydro-ß-carbolines are of significant interest due to the broad spectrum of biological activity of the target molecules. In the plant kingdom strictosidine synthases catalyze the C-C coupling via a Pictet-Spengler reaction of tryptamine and secologanin to exclusively form the (S)-configured tetrahydro-ß-carboline (S)-strictosidine. Investigating the biocatalytic Pictet-Spengler reaction of tryptamine with small-molecular-weight aliphatic aldehydes revealed that the strictosidine synthases gave unexpectedly access to the (R)-configured product. Developing an efficient expression method of the catalyst allowed the preparative transformation of various aldehydes giving the products with up to >98% ee. With this tool in hand a chemoenzymatic two-step synthesis of (R)-harmicine was achieved giving (R)-harmicine in 67% overall yield in optically pure form. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Psychotropic Medications in Children with Autism Spectrum Disorders: A Systematic Review and Synthesis for Evidence-Based Practice

ERIC Educational Resources Information Center

Siegel, Matthew; Beaulieu, Amy A.

2012-01-01

This paper presents a systematic review, rating and synthesis of the empirical evidence for the use of psychotropic medications in children with autism spectrum disorders (ASD). Thirty-three randomized controlled trials (RCTs) published in peer-reviewed journals qualified for inclusion and were coded and analyzed using a systematic evaluative…

Synthesis and Characterization of Antimicrobial Nanomaterials

DTIC Science & Technology

2013-01-01

coatings have broad application in medical and food processing fields. Additional potential exists for active disinfection/decontamination processes as well...technique to form homogenous silica nanoparticles. The reaction also provides a method to entrap additional enzyme in silica matrices. When additional ...elucidate the mechanism of lysozyme-mediated silica formation.22 The biocidal spectrum of the material can be broadened by addition of other

Synthesis of carbon nanospheres using fallen willow leaves and adsorption of Rhodamine B and heavy metals by them.

PubMed

Qu, Jiao; Zhang, Qian; Xia, Yunsheng; Cong, Qiao; Luo, Chunqiu

2015-01-01

This paper focuses on the synthesis of carbon nanospheres (CNSs) using fallen willow leaves as a low-cost precursor. The scanning electron microscopy (SEM) image and transmission electron microscopy (TEM) image demonstrated that the structure of synthesized CNSs was spherical, with a diameter of 100 nm. The crystal structure and chemical information were characterized by Raman spectrum and energy-dispersive spectrum (EDS), respectively. BET results showed that the CNSs had a larger specific surface area of 294.32 m(2) g(-1), which makes it a potentially superior adsorbent. Rh-B and heavy metal ions such as Cu(2+), Zn(2+), and Cr(6+) were used as targets to investigate the adsorption capacity of the CNSs. The effects of adsorption parameters such as adsorption equilibrium time, dose of CNSs, adsorption kinetics, and effect factors were also studied. These findings not only established a cost-effective method of synthesizing CNSs using fallen willow leaves but also broadened the potential application range of these CNSs.

Green synthesis of gold nanoparticles using Trigonella foenum-graecum and its size-dependent catalytic activity

NASA Astrophysics Data System (ADS)

Aswathy Aromal, S.; Philip, Daizy

2012-11-01

The development of new synthesis methods for monodispersed nanocrystals using cheap and nontoxic chemicals, environmentally benign solvents and renewable materials remains a challenge to the scientific community. Most of the current methods involve known protocols which may be potentially harmful to either environment or human health. Recent research has been focused on green synthesis methods to produce new nanomaterials, ecofriendly and safer with sustainable commercial viability. The present work reports the green synthesis of gold nanoparticles using the aqueous extract of fenugreek (Trigonella foenum-graecum) as reducing and protecting agent. The pathway is based on the reduction of AuCl4- by the extract of fenugreek. This method is simple, efficient, economic and nontoxic. Gold nanoparticles having different sizes in the range from 15 to 25 nm could be obtained by controlling the synthesis parameters. The nanoparticles have been characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and FTIR analysis. The high crystallinity of nanoparticles is evident from clear lattice fringes in the HRTEM images, bright circular spots in the SAED pattern and peaks in the XRD pattern. FTIR spectrum indicates the presence of different functional groups present in the biomolecule capping the nanoparticles. The synthesized gold nanoparticles show good catalytic activity for the reduction of 4-nitrophenol to 4-aminophenol by excess NaBH4. The catalytic activity is found to be size-dependent, the smaller nanoparticles showing faster activity.

Selecting the optimal synthesis parameters of InP/CdxZn1-xSe quantum dots for a hybrid remote phosphor white LED for general lighting applications.

PubMed

Ryckaert, Jana; Correia, António; Tessier, Mickael D; Dupont, Dorian; Hens, Zeger; Hanselaer, Peter; Meuret, Youri

2017-11-27

Quantum dots can be used in white LEDs for lighting applications to fill the spectral gaps in the combined emission spectrum of the blue pumping LED and a broad band phosphor, in order to improve the source color rendering properties. Because quantum dots are low scattering materials, their use can also reduce the amount of backscattered light which can increase the overall efficiency of the white LED. The absorption spectrum and narrow emission spectrum of quantum dots can be easily tuned by altering their synthesis parameters. Due to the re-absorption events between the different luminescent materials and the light interaction with the LED package, determining the optimal quantum dot properties is a highly non-trivial task. In this paper we propose a methodology to select the optimal quantum dot to be combined with a broad band phosphor in order to realize a white LED with optimal luminous efficacy and CRI. The methodology is based on accurate and efficient simulations using the extended adding-doubling approach that take into account all the optical interactions. The method is elaborated for the specific case of a hybrid, remote phosphor white LED with YAG:Ce phosphor in combination with InP/CdxZn 1-x Se type quantum dots. The absorption and emission spectrum of the quantum dots are generated in function of three synthesis parameters (core size, shell size and cadmium fraction) by a semi-empirical 'quantum dot model' to include the continuous tunability of these spectra. The sufficiently fast simulations allow to scan the full parameter space consisting of these synthesis parameters and luminescent material concentrations in terms of CRI and efficacy. A conclusive visualization of the final performance allows to make a well-considered trade-off between these performance parameters. For the hybrid white remote phosphor LED with YAG:Ce and InP/CdxZn 1-x Se quantum dots a CRI Ra = 90 (with R9>50) and an overall efficacy of 110 lm/W is found.

Cyclo[n]pyrroles and methods thereto

DOEpatents

Sessler, Jonathan L.; Seidel, Daniel; Bolze, Frederic R.; Koehler, Thomas

2006-01-10

The present invention provides an oxidative coupling procedure that allows efficient synthesis of novel cyclo[n]pyrrole macrocycles. Therefore, the present invention provides cyclo[n]pyrroles where n is 6, 7, 8, 9, 10, 11, or 12, and derivatives, multimers, isomers, and ion and neutral molecule complexes thereof as new compositions of matter. A protonated form of cyclo[n]pyrrole displays a gap of up to 700 nm between strong Soret and Q-like absorption bands in the electronic spectrum, demonstrating no significant ground state absorption in the visible portion of the electronic spectrum. Uses of cyclo[n]pyrroles as separation media, nonlinear optical materials, information storage media and infrared filters are provided.

Band selection method based on spectrum difference in targets of interest in hyperspectral imagery

NASA Astrophysics Data System (ADS)

Zhang, Xiaohan; Yang, Guang; Yang, Yongbo; Huang, Junhua

2016-10-01

While hyperspectral data shares rich spectrum information, it has numbers of bands with high correlation coefficients, causing great data redundancy. A reasonable band selection is important for subsequent processing. Bands with large amount of information and low correlation should be selected. On this basis, according to the needs of target detection applications, the spectral characteristics of the objects of interest are taken into consideration in this paper, and a new method based on spectrum difference is proposed. Firstly, according to the spectrum differences of targets of interest, a difference matrix which represents the different spectral reflectance of different targets in different bands is structured. By setting a threshold, the bands satisfying the conditions would be left, constituting a subset of bands. Then, the correlation coefficients between bands are calculated and correlation matrix is given. According to the size of the correlation coefficient, the bands can be set into several groups. At last, the conception of normalized variance is used on behalf of the information content of each band. The bands are sorted by the value of its normalized variance. Set needing number of bands, and the optimum band combination solution can be get by these three steps. This method retains the greatest degree of difference between the target of interest and is easy to achieve by computer automatically. Besides, false color image synthesis experiment is carried out using the bands selected by this method as well as other 3 methods to show the performance of method in this paper.

[Quantitative determination of 7-phenoxyacetamidodesacetoxycephalosporanic acid].

PubMed

Dzegilenko, N B; Riabova, N M; Zinchenko, E Ia; Korchagin, V B

1976-11-01

7-Phenoxyacetamidodesacetoxycephalosporanic acid, an intermediate product in synthesis of cephalexin, was prepared by oxydation of phenoxymethylpenicillin into the respective sulphoxide and transformation of the latter. The UV-spectra of the reaction products were studied. A quantitative method is proposed for determination of 7-phenoxyacetamidodesacetoxycephalosporanic acid in the finished products based on estimation os the coefficient of specific extinction of the ethanol solutions at a wave length of 268 um in the UV-spectrum region in combination with semiquantitative estimation of the admixtures with the method of thin-layer chromatography.

Bacterial fatty acid metabolism in modern antibiotic discovery.

PubMed

Yao, Jiangwei; Rock, Charles O

2017-11-01

Bacterial fatty acid synthesis is essential for many pathogens and different from the mammalian counterpart. These features make bacterial fatty acid synthesis a desirable target for antibiotic discovery. The structural divergence of the conserved enzymes and the presence of different isozymes catalyzing the same reactions in the pathway make bacterial fatty acid synthesis a narrow spectrum target rather than the traditional broad spectrum target. Furthermore, bacterial fatty acid synthesis inhibitors are single-targeting, rather than multi-targeting like traditional monotherapeutic, broad-spectrum antibiotics. The single-targeting nature of bacterial fatty acid synthesis inhibitors makes overcoming fast-developing, target-based resistance a necessary consideration for antibiotic development. Target-based resistance can be overcome through multi-targeting inhibitors, a cocktail of single-targeting inhibitors, or by making the single targeting inhibitor sufficiently high affinity through a pathogen selective approach such that target-based mutants are still susceptible to therapeutic concentrations of drug. Many of the pathogens requiring new antibiotic treatment options encode for essential bacterial fatty acid synthesis enzymes. This review will evaluate the most promising targets in bacterial fatty acid metabolism for antibiotic therapeutics development and review the potential and challenges in advancing each of these targets to the clinic and circumventing target-based resistance. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemo-enzymatic synthesis of isotopically labeled nicotinamide riboside.

PubMed

Tran, Ai; Yokose, Ryota; Cen, Yana

2018-05-15

As a cofactor for numerous reactions, NAD+ is found widely dispersed across many maps of cellular metabolism. This core redox role alone makes the biosynthesis of NAD+ of great interest. Recent studies have revealed new biological roles for NAD+ as a substrate for diverse enzymes that regulate a broad spectrum of key cellular tasks. These NAD+-consuming enzymes further highlight the importance of understanding NAD+ biosynthetic pathways. In this study, we developed a chemo-enzymatic synthesis of isotopically labeled NAD+ precursor, nicotinamide riboside (NR). The synthesis of NR isotopomers allowed us to unambiguously determine that NR is efficiently converted to NAD+ in the cellular environment independent of degradation to nicotinamide, and it is incorporated into NAD+ in its intact form. The versatile synthetic method along with the isotopically labeled NRs will provide powerful tools to further decipher the important yet complicated NAD+ metabolism.

Regulating the Emission Spectrum of CsPbBr3 from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor

PubMed Central

Tang, Yong; Lu, Hanguang; Rao, Longshi; Ding, Xinrui; Yan, Caiman; Yu, Binhai

2018-01-01

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr3 QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr3 QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing halide component. The mechanism of photoluminescence (PL) spectral shift of CsPbBr3 QDs was investigated, the result shows that the supersaturation control enabled by the superior mass and heat transfer performance in the microchannel is the key to achieve the wide range of PL spectrum, with only a change in the setting of the temperature controller required. The wide spectrum of CsPbBr3 QDs can be applied to light-emitting diodes (LEDs), photoelectric sensors, lasers, etc. PMID:29498710

Most genetic risk for autism resides with common variation.

PubMed

Gaugler, Trent; Klei, Lambertus; Sanders, Stephan J; Bodea, Corneliu A; Goldberg, Arthur P; Lee, Ann B; Mahajan, Milind; Manaa, Dina; Pawitan, Yudi; Reichert, Jennifer; Ripke, Stephan; Sandin, Sven; Sklar, Pamela; Svantesson, Oscar; Reichenberg, Abraham; Hultman, Christina M; Devlin, Bernie; Roeder, Kathryn; Buxbaum, Joseph D

2014-08-01

A key component of genetic architecture is the allelic spectrum influencing trait variability. For autism spectrum disorder (herein termed autism), the nature of the allelic spectrum is uncertain. Individual risk-associated genes have been identified from rare variation, especially de novo mutations. From this evidence, one might conclude that rare variation dominates the allelic spectrum in autism, yet recent studies show that common variation, individually of small effect, has substantial impact en masse. At issue is how much of an impact relative to rare variation this common variation has. Using a unique epidemiological sample from Sweden, new methods that distinguish total narrow-sense heritability from that due to common variation and synthesis of results from other studies, we reach several conclusions about autism's genetic architecture: its narrow-sense heritability is ∼52.4%, with most due to common variation, and rare de novo mutations contribute substantially to individual liability, yet their contribution to variance in liability, 2.6%, is modest compared to that for heritable variation.

Bi-Level Integrated System Synthesis (BLISS) for Concurrent and Distributed Processing

NASA Technical Reports Server (NTRS)

Sobieszczanski-Sobieski, Jaroslaw; Altus, Troy D.; Phillips, Matthew; Sandusky, Robert

2002-01-01

The paper introduces a new version of the Bi-Level Integrated System Synthesis (BLISS) methods intended for optimization of engineering systems conducted by distributed specialty groups working concurrently and using a multiprocessor computing environment. The method decomposes the overall optimization task into subtasks associated with disciplines or subsystems where the local design variables are numerous and a single, system-level optimization whose design variables are relatively few. The subtasks are fully autonomous as to their inner operations and decision making. Their purpose is to eliminate the local design variables and generate a wide spectrum of feasible designs whose behavior is represented by Response Surfaces to be accessed by a system-level optimization. It is shown that, if the problem is convex, the solution of the decomposed problem is the same as that obtained without decomposition. A simplified example of an aircraft design shows the method working as intended. The paper includes a discussion of the method merits and demerits and recommendations for further research.

Synthesis and Luminescence Properties of Orange-Red Phosphors Na Y (WO4)2: Eu3+, Sm3+

NASA Astrophysics Data System (ADS)

Yu, Hong; Chen, Shanyong; Chen, Jinlei

2017-12-01

Orange-red phosphors NaY(WO4)2:Eu3+, Sm3+ were successfully synthesised by hydrothermal synthesis method. The photoluminescence (PL) properties were investigated. The PL emission spectrum of Na Y (WO4)2: Eu3+ shows good luminous properties under 398 nm, which mainly located at 596 and 615 nm, with the additional of Sm3+ could broaden and increase emission intensity of Eu3+, which could be suitable for the excitation of UV light emitting diodes (LEDs) (∼400 nm). The PL results indicated that Na Y (WO4)2: Eu3+, Sm3+ may be a promising red phosphor candidate for use in white LEDs.

Synthesis of Nanosecond Ultrawideband Radiation Pulses

NASA Astrophysics Data System (ADS)

Koshelev, V. I.; Plisko, V. V.; Sevostyanov, E. A.

2017-12-01

The synthesis of electromagnetic pulses with an extended spectrum by summing pulses of different duration in free space has been studied. The radiation spectrum has been estimated analytically for a 4-element array of combined antennas excited by bipolar voltage pulses of duration 0.5, 1, 2, and 3 ns. It has been shown experimentally that radiation with a spectral width of more than three octaves can be produced using a 2×2 array of combined antennas excited by bipolar pulses of duration 2 and 3 ns.

Non-Local Thermodynamic Equilibrium Spectrum Synthesis of Type IA Supernovae

NASA Astrophysics Data System (ADS)

Nugent, Peter Edward

1997-09-01

Type Ia supernovae (SNe Ia) are valuable distance indicators for cosmology and the elements they eject are are important for nucleosynthesis. They appear to be thermonuclear disruptions of carbon-oxygen white dwarfs that accrete from companion stars until they approach the Chandrasekbar mass, and there is a suspicion that the propagation of the nuclear burning front involves a transition from a deflagration to a detonation. Detailed modeling of the atmospheres and spectra of SNe Ia is needed to advance our understanding of SNe Ia. Comparison of synthetic and observed spectra provides information on the temperature, density, velocity, and composition of the ejected matter and thus constrain hydrodynamical models. In addition, the expanding photosphere method yields distances to individual events that are independent of distances based on the decay of 56Ni in SNe Ia and of Cepheid variable stars in the parent galaxies. This thesis is broken down into 4 major sections, each highlighting a different way with which to use spectrum synthesis to analyze SNe Ia. Chapters 2 and 3 look at normal SNe Ia and their potential use as distance indicators using SEAM. Chapter 4 examines spectral correlations with luminosity in SNe Ia and provides a plausible explanation for these correlations via spectrum synthesis. In Chapter 5 the spectra of various hydrodynamical models are calculated in an effort to answer the question of which current progenitor/explosion model is the most plausible for a SN Ia. Finally, we look at the importance of NLTE calculations and line identifications in Chapter 6. Also included are two appendices which contain more technical information concerning γ-ray deposition and the thermalization parameter.

Hydrothermal synthesis and characterization of a novel supramolecular network compound of Co(NIA) 2(H 2O) 4 with molecular ladder hydrogen bond chains (NIA=nicotinate)

NASA Astrophysics Data System (ADS)

Jia, Hong-Bin; Yu, Jie-Hui; Xu, Ji-Qing; Ye, Ling; Ding, Hong; Jing, Wei-Jie; Wang, Tie-Gang; Xu, Jia-Ning; Li, Zeng-Chun

2002-10-01

By hydrothermal method, a novel supramolecular compound, Co(NIA) 2(H 2O) 4 was synthesized and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffractometer, indicating that it is a novel polyporous supramolecule with molecular ladder hydrogen-bonded chains. TGA curve shows its thermal stability up to 520 °C.

Studies on Optical and Electrical Properties of Hafnium Oxide Nanoparticles

NASA Astrophysics Data System (ADS)

Jayaraman, Venkatachalam; Sagadevan, Suresh; Sudhakar, Rajesh

2017-07-01

In this paper, the synthesis and physico-chemical properties of hafnium oxide nanoparticles (HfO2 NPs) are analyzed and reported. The synthesis was carried out by the precipitation route by using hafnium tetrachloride (HfCl4) as precursor material with potassium hydroxide (KOH) dissolved in Millipore water. In the precipitation technique, the chemical reaction is comparatively simple, low-cost and non-toxic compared to other synthetic methods. The synthesized HfO2 NPs were characterized by using powder x-ray diffraction (PXRD), ultraviolet-visible (UV-Vis) spectroscopy, Raman analysis, and high-resolution transmission electron microscopy (HRTEM). The monoclinic structure of the HfO2 NPs was resolved utilizing x-ray diffraction (XRD). The optical properties were studied from the UV-Vis absorption spectrum. The optical band gap of the HfO2NPs was observed to be 5.1 eV. The Raman spectrum shows the presence of HfO2 NPs. The HRTEM image showed that the HfO2 NPs were of spherical shape with an average particle size of around 28 nm. The energy-dispersive x-ray spectroscopy (EDS) spectrum obviously demonstrated the presence of HfO2 NPs. Analysis and studies on the dielectric properties of the HfO2 NPs such as the dielectric constant, the dielectric loss, and alternating current (AC) conductivity were carried out at varying frequencies and temperatures.

Green synthesis of gold nanoparticles using Citrus maxima peel extract and their catalytic/antibacterial activities.

PubMed

Yuan, Chun-Gang; Huo, Can; Gui, Bing; Cao, Wei-Ping

2017-08-01

The peel of Citrus maxima ( C. maxima ) is the primary byproducts during the process of fruit or juice in food industries, and it was always considered as biomass waste for further treatments. In this study, the authors reported a simple and eco-friendly method to synthesise gold nanoparticles (AuNPs) using C. maxima peel extract as reducing and capping agents. The synthesised AuNPs were characterised by UV-visible spectrum, X-ray diffraction (XRD), transmission electron microscope (TEM) and Fourier-transform infrared spectroscopy (FTIR). The UV-visible spectrum of the AuNPs colloid showed a characteristic peak at 540 nm. The peaks of XRD analysis at (2 θ ) 38.30°, 44.28°, 64.62°, 77.57° and 81.75° were assigned to (111), (200), (220), (311) and (222) planes of the face-centered cubic (fcc) lattice of gold. The TEM images showed that AuNPs were nearly spherical in shape with the size of 8-25 nm. The FTIR spectrum revealed that some bioactive compounds capped the surface of synthesised AuNPs. The biosynthesised AuNPs performed strong catalytic activity in degradation of 4-nitrophenol to 4-aminophenol and good antibacterial activity against both gram negative ( Escherichia coli ) and gram positive ( Staphylococcus aureus ) bacterium. The synthesis procedure was proved simple, cost effective and environment friendly.

Fast data reconstructed method of Fourier transform imaging spectrometer based on multi-core CPU

NASA Astrophysics Data System (ADS)

Yu, Chunchao; Du, Debiao; Xia, Zongze; Song, Li; Zheng, Weijian; Yan, Min; Lei, Zhenggang

2017-10-01

Imaging spectrometer can gain two-dimensional space image and one-dimensional spectrum at the same time, which shows high utility in color and spectral measurements, the true color image synthesis, military reconnaissance and so on. In order to realize the fast reconstructed processing of the Fourier transform imaging spectrometer data, the paper designed the optimization reconstructed algorithm with OpenMP parallel calculating technology, which was further used for the optimization process for the HyperSpectral Imager of `HJ-1' Chinese satellite. The results show that the method based on multi-core parallel computing technology can control the multi-core CPU hardware resources competently and significantly enhance the calculation of the spectrum reconstruction processing efficiency. If the technology is applied to more cores workstation in parallel computing, it will be possible to complete Fourier transform imaging spectrometer real-time data processing with a single computer.

Synthesis, Reactivity, and Characterization of (-Hexacarbocyclic) Manganese Dicarbonyl Complexes with Sulfur and Phosphorus Ligands

DTIC Science & Technology

1993-05-01

Coupling of SCHS (6 221) and ring methyls (6 16.8) in 52 in (a)13C[’H) and (b) 13C NMR Spectra ......................... 128 14. Low- energy collision...spectrum of 51 (m/z 351) .................. 136 15. Low- energy collision spectrum of 52 (m/z 593) .................. 138 16. Low- energy collision...spectrum of 53 (m/z 390) .................. 139 17. Low- energy collision spectrum of 54 (m/z 410) .................. 140 18. Low- energy collision spectrum of

The Lived Experience of US Parents of Children with Autism Spectrum Disorders: A Systemic Review and Meta-Synthesis

ERIC Educational Resources Information Center

Corcoran, Jacqueline; Berry, Amber; Hill, Stephanie

2015-01-01

Current US statistics indicate that 1 in 68 children is diagnosed with an autistic spectrum disorder (Centers for Disease Control (2014) Prevalence of autism spectrum disorder among children aged 8 years--autism and developmental disabilities monitoring network, 11 Sites, United States, 2010. "Morbidity and Mortality Weekly Report"…

Spectrophotometric Investigations of Macrolide Antibiotics: A Brief Review

PubMed Central

Keskar, Mrudul R; Jugade, Ravin M

2015-01-01

Macrolides, one of the most commonly used class of antibiotics, are a group of drugs produced by Streptomyces species. They belong to the polyketide class of natural products. Their activity is due to the presence of a large macrolide lactone ring with deoxy sugar moieties. They are protein synthesis inhibitors and broad-spectrum antibiotics, active against both gram-positive and gram-negative bacteria. Different analytical techniques have been reported for the determination of macrolides such as chromatographic methods, flow injection methods, spectrofluorometric methods, spectrophotometric methods, and capillary electrophoresis methods. Among these methods, spectrophotometric methods are sensitive and cost effective for the analysis of various antibiotics in pharmaceutical formulations as well as biological samples. This article reviews different spectrophotometric methods for the determination of macrolide antibiotics. PMID:26609215

Mangifera Indica leaf-assisted biosynthesis of well-dispersed silver nanoparticles

NASA Astrophysics Data System (ADS)

Philip, Daizy

2011-01-01

The use of various parts of plants for the synthesis of nanoparticles is considered as a green technology as it does not involve any harmful chemicals. The present study reports a facile and rapid biosynthesis of well-dispersed silver nanoparticles. The method developed is environmentally friendly and allows the reduction to be accelerated by changing the temperature and pH of the reaction mixture consisting of aqueous AgNO 3 and Mangifera Indica leaf extract. At a pH of 8, the colloid consists of well-dispersed triangular, hexagonal and nearly spherical nanoparticles having size ˜20 nm. The UV-vis spectrum of silver nanoparticles gave surface plasmon resonance (SPR) at 439 nm. The synthesized nanocrystals were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. Water soluble organics present in the leaf are responsible for the reduction of silver ions. This green method provides faster synthesis comparable to chemical methods and can be used in areas such as cosmetics, foods and medical applications.

Rapid green synthesis of spherical gold nanoparticles using Mangifera indica leaf

NASA Astrophysics Data System (ADS)

Philip, Daizy

2010-11-01

This paper reports the rapid biological synthesis of spherical gold nanoparticles at room temperature using fresh/dry leaf extract of Mangifera indica. This is a simple, cost-effective, stable for long time and reproducible aqueous synthesis method to obtain a self-assembly of nearly monodispersed Au nanoparticles of size ˜20 nm and 17 nm. The nanoparticles were obtained within 2 min of addition of the extract to the solution of HAuCl 4·3H 2O and the colloid is found to be stable for more than 5 months. Smaller and more uniformly distributed particles could be obtained with dried leaf extract. The nanoparticles obtained are characterized by UV-vis, transmission electron microscopy (TEM) and X-ray diffraction (XRD). Crystalline nature of the nanoparticles in the fcc structure is confirmed by the peaks in the XRD pattern corresponding to (1 1 1), (2 0 0), (2 2 0), (3 1 1) and (2 2 2) planes, bright circular spots in the selected area electron diffraction (SAED) and clear lattice fringes in the high-resolution TEM image. The possible biomolecules responsible for efficient stabilization are suggested by studying the FTIR spectrum of the sample. This environmentally benign method provides much faster synthesis and colloidal stability comparable to those of chemical reduction.

OH rotational temperature measurements via a two temperature distribution analysis in plasma with water microdroplets

NASA Astrophysics Data System (ADS)

Tsumaki, Masanao; Ito, Tsuyohito

2016-09-01

We study plasma processing with water/solution microdroplets for a new nanoparticle synthesis method. In the process, it is important to know gas temperature (Tg) for understanding the mechanism of the particle growth and controlling its properties. Since OH emissions are naturally observed in such plasma, the rotational temperature (Tr) of OH (A-X) is estimated and compared with Tr from N2 (C-B). The plasma is generated by dielectric barrier discharges in He with N2 (2.6%) gas flow, and microdroplets are generated by an ultrasonic atomizer and carried into He/N2 plasma. Optical emission spectroscopy revealed that with the increase of voltage and frequency of plasma generation, the Tr of N2 increases. While the good theoretical spectrum fit on N2 experimental spectrum could be achieved, it was hard to obtain a reasonable fit for the OH spectrum with a single rotational energy distribution. On the other hand, two rotational distribution analysis could reproduce the experimental spectrum of OH and the lower Tr agrees to Tr by N2. The results suggest that the lower Tr obtained with the two rotational temperature analysis of OH spectrum represents Tg of the environment.

[Study of cholesterol concentration based on serum UV-visible absorption spectrum].

PubMed

Zhu, Wei-Hua; Zhao, Zhi-Min; Guo, Xin; Chen, Hui

2009-04-01

In the present paper, UV-visible absorption spectrum and neural network theory were used for the analysis of cholesterol concentration. Experimental investigation shows that the absorption spectrum has the following characteristics in the wave band of 350-600 nm: (1) There is a stronger absorption peak at 416 nm for the test sample with different cholesterol concentration; (2) There is a shoulder peak between 450 and 500 nm, whose central wavelength is 460 nm; (3) There is a weaker peak at 578 nm; (4) Absorption spectrums shape of different cholesterol concentration is different obviously. The absorption spectrum of serum is the synthesis result of cholesterol and other components (such as sugar), and the information is contained at each wavelength. There is no significant correlation between absorbance and cholesterol content at 416 nm, showing a random relation, so whether cholesterol content is abnormal is not determined by the absorbance peak at 416 nm. Based on the evident correlation between serum absorption spectrum and cholesterol concentration in the wave band of 455-475 nm, a neural network model was built to predict the cholesterol concentration. The correlation coefficient between predicted cholesterol content output A and objectives T reaches 0.968, which can be regarded as better prediction, and it provides a spectra test method of cholesterol concentration.

Design and analysis of all-dielectric broadband nonpolarizing parallel-plate beam splitters.

PubMed

Wang, Wenliang; Xiong, Shengming; Zhang, Yundong

2007-06-01

Past research on the all-dielectric nonpolarizing beam splitter is reviewed. With the aid of the needle thin-film synthesis method and the conjugate graduate refine method, three different split ratio nonpolarizing parallel-plate beam splitters over a 200 nm spectral range centered at 550 nm with incidence angles of 45 degrees are designed. The chosen materials component and the initial stack are based on the Costich and Thelen theories. The results of design and analysis show that the designs maintain a very low polarization ratio in the working range of the spectrum and has a reasonable angular field.

All-dielectric broadband non-polarizing parallel plate beam splitter operating between 450-650nm

NASA Astrophysics Data System (ADS)

Wang, Wenliang; Xiong, Shenming; Zhang, Yundong

2007-12-01

Past research on all-dielectric non-polarizing beam splitter is reviewed. With the aid of needle thin film synthesis method and conjugate graduate refining method, three non-polarizing parallel plate beam splitters with different split ratios over a 200nm spectral range centered at 550nm with incidence angle 45° are designed. Selection of material components and initial stack are based on Costich and Thelen's theory. The results of design and analysis show that it maintains a very low polarization ratio in the working range of spectrum and has a reasonable angular field.

PREFACE: Stellar Atmospheres in the Gaia Era - Preface

NASA Astrophysics Data System (ADS)

Lobel, Alex; De Greve, Jean-Pierre; Van Rensbergen, Walter

2011-12-01

Volume 328 (2011) of the Journal of Physics: Conference Series provides a record of the invited and contributed talks, and of the posters presented at the GREAT-ESF workshop entitled `Stellar Atmospheres in the Gaia Era: Quantitative Spectroscopy and Comparative Spectrum Modelling' (http://great-esf.oma.be and mirrored at http://spectri.freeshell.org/great-esf). The conference was held on 23-24 June 2011 at the Vrije Universiteit Brussel, Belgium. 47 scientists from 11 countries around the world attended the workshop. The ESA-Gaia satellite (launch mid 2013) will observe a billion stellar objects in the Galaxy and provide spectrophotometric and high-resolution spectra of an unprecedented number of stars observed with a space-based instrument. The confrontation of these data with theoretical models will significantly advance our understanding of the physics of stellar atmospheres. New stellar populations such as previously unknown emission line stars will be discovered, and fundamental questions such as the basic scenarios of stellar evolution will be addressed with Gaia data. The 33 presentations and 4 main discussion sessions at the workshop addressed important topics in spectrum synthesis methods and detailed line profile calculations urgently needed for accurate modelling of stellar spectra. It brought together leading scientists and students of the stellar physics communities investigating hot and cool star spectra. The scientific programme of the workshop consisted of 23 oral (6 invited) and 10 poster presentations about cool stars (first day; Comparative Spectrum Modelling and Quantitative Spectroscopy of Cool Stars), and hot stars (second day; Quantitative Spectroscopy of Hot Stars). The hot and cool stars communities use different spectrum modelling codes for determining basic parameters such as the effective temperature, surface gravity, iron abundance, and the chemical composition of stellar atmospheres. The chaired sessions of the first day highlighted new research results with spectral synthesis codes developed for cool stars, while the second day focused on codes applied for modeling the spectra of hot stars. The workshop addressed five major topics in stellar atmospheres research: Spectrum synthesis codes Radiation hydrodynamics codes Atmospheric parameters, abundance, metallicity, and chemical tagging studies Large spectroscopic surveys New atomic database The workshop presentations discussed various important scientific issues by comparing detailed model spectra to identify differences that can influence and bias the resulting atmospheric parameters. Theoretical line-blanketed model spectra were compared in detail to high-resolution spectroscopic observations. Stellar spectra computed (i.e., in the Gaia Radial Velocity Spectrometer wavelength range) with 1-D model atmosphere structures were mutually compared, but also to 3-D models from advanced radiation hydrodynamics codes. Atmospheric parameters derived from spectrum synthesis calculations assuming Local Thermodynamic Equilibrium (LTE) were evaluated against more sophisticated non-LTE models of metal-poor stars and the extended atmospheres of giants and supergiants. The workshop presented an overview of high-resolution synthetic spectral libraries of model spectra computed with the synthesis codes. The spectral model grids will be utilized to derive stellar parameters with the Discrete Source Classifier Algorithms currently under development in the Gaia DPAC consortium (http://www.rssd.esa.int/index.php?project=GAIA&page=DPAC_Introduction). They are implemented for training Gaia data analysis algorithms for the classification of a wide variety of hot and cool star types; FGK and M stars, OB stars, white dwarfs, red supergiants, peculiar A and B stars, carbon stars, ultra cool dwarfs, various types of emission line stars, Be stars, Wolf-Rayet stars, etc. A substantial number of oral and poster presentations discussed different techniques for measuring the abundance of various chemical elements from stellar spectra. The presented methods utilize spectra observed with large spectral dispersion, for example for accurately measuring iron, carbon, and nitrogen abundances. These methods are important for ongoing development and testing of automated and supervised algorithms for determining detailed chemical composition in tagging studies of large (chemo-dynamical) spectroscopic surveys planned to complement the Gaia (astrometric and kinematic) census of the Galaxy. The complete scientific programme is available here. The workshop website also offers the presentation viewgraphs (in PDF format) and some nice photographs of the talks and poster breaks http://great-esf.oma.be/program.php.

Facile green synthesis of variable metallic gold nanoparticle using Padina gymnospora, a brown marine macroalga

NASA Astrophysics Data System (ADS)

Singh, M.; Kalaivani, R.; Manikandan, S.; Sangeetha, N.; Kumaraguru, A. K.

2013-04-01

The process of development of reliable and eco-friendly metallic nanoparticles is an important step in the field of nanotechnology. To achieve this, use of natural sources like biological systems becomes essential. In the present work, extracellular biosynthesis of gold nanoparticles using Padina gymnospora has been attempted and achieved rapid formation of gold nanoparticles in a short duration. The UV-vis spectrum of the aqueous medium containing gold ion showed peak at 527 nm corresponding to the plasmon absorbance of gold nanoparticles. Scanning electron microscopy showed the formation of well-dispersed gold nanoparticles. FTIR spectra of brown alga confirmed that hydroxyl groups present in the algal polysaccharides were involved in the gold bioreduction. AFM analysis showed the results of particle sizes (53-67 nm) and average height of the particle roughness (60.0 nm). X-ray diffraction (XRD) spectrum of the gold nanoparticles exhibited Bragg reflections corresponding to gold nanoparticles. This environment-friendly method of biological gold nanoparticle synthesis can be applied potentially in various products that directly come in contact with the human body, such as cosmetics, and foods and consumer goods, besides medical applications.

Direct synthesis of antimicrobial coatings based on tailored bi-elemental nanoparticles

NASA Astrophysics Data System (ADS)

Benetti, Giulio; Cavaliere, Emanuele; Canteri, Adalberto; Landini, Giulia; Rossolini, Gian Maria; Pallecchi, Lucia; Chiodi, Mirco; Van Bael, Margriet J.; Winckelmans, Naomi; Bals, Sara; Gavioli, Luca

2017-03-01

Ultrathin coatings based on bi-elemental nanoparticles (NPs) are very promising to limit the surface-related spread of bacterial pathogens, particularly in nosocomial environments. However, tailoring the synthesis, composition, adhesion to substrate, and antimicrobial spectrum of the coating is an open challenge. Herein, we report on a radically new nanostructured coating, obtained by a one-step gas-phase deposition technique, and composed of bi-elemental Janus type Ag/Ti NPs. The NPs are characterized by a cluster-in-cluster mixing phase with metallic Ag nano-crystals embedded in amorphous TiO2 and present a promising antimicrobial activity including also multidrug resistant strains. We demonstrate the flexibility of the method to tune the embedded Ag nano-crystals dimension, the total relative composition of the coating, and the substrate type, opening the possibility of tailoring the dimension, composition, antimicrobial spectrum, and other physical/chemical properties of such multi-elemental systems. This work is expected to significantly spread the range of applications of NPs coatings, not only as an effective tool in the prevention of healthcare-associated infections but also in other technologically relevant fields like sensors or nano-/micro joining.

Fourier Image Synthesis and Slope Spectrum Analysis of Deepwater, Windwave Scenes Viewed at Brewster’s Angle

DTIC Science & Technology

1990-01-01

reflection is simulated by a one- level ray trace with selective filtering of the RGB color ’spectrum’ Fractal and sequential Markov-chain synthesis tech...above water level [cm/sec], and vfric = the wind friction velocity at the water surface (i.e. z = 0 cm). vfric and the wind velocity v [cm/sec] at height...12 cm/sec 1000 0 -4.5 -4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 -. 5 0 .5 1.0 LOGI0(k (k: 1/cm) ------------------------------------------------------ FIGUE

EPR and optical investigations of LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singh, Vijay, E-mail: vijayjiin2006@yahoo.com; Sivaramaiah, G.; Rao, J.L.

2014-12-15

Graphical abstract: The EPR spectrum of as-prepared LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor at 110 K. - Highlights: • Using the combustion synthesis, LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor has been prepared in a few minutes. • Optical investigation indicates that Cr{sup 3+} ions are present in octahedral symmetry. • The EPR signals indicate that exchange coupled Cr{sup 3+}–Cr{sup 3+} ion pairs in weakly distorted sites. - Abstract: The LaMgAl{sub 11}O{sub 19}:Cr{sup 3+} phosphor has been prepared by a low-temperature combustion synthesis method. As-prepared combustion synthesized powder was characterized using powder X-ray diffraction (XRD), diffuse reflectance (DRS), electron paramagnetic resonance (EPR) andmore » photoluminescence (PL) studies. The X-ray diffraction pattern reveals crystalline hexagonal phases. The UV–vis diffuse reflectance spectrum exhibits three broad bands characteristic of Cr{sup 3+} ions in octahedral symmetry. The EPR spectrum exhibits several resonance signals. The signals with the effective g values at g = 4.84, 3.64 and 2.26 have been attributed to the isolated Cr{sup 3+} ions. The signal with the effective g value at g = 1.94 has been attributed to exchange coupled Cr{sup 3+}–Cr{sup 3+} ion pairs. The PL studies exhibit several bands characteristic of Cr{sup 3+} ions in octahedral symmetry.« less

Phenol-selective mass spectrometric analysis of jet fuel.

PubMed

Zhu, Haoxuan; Janusson, Eric; Luo, Jingwei; Piers, James; Islam, Farhana; McGarvey, G Bryce; Oliver, Allen G; Granot, Ori; McIndoe, J Scott

2017-08-21

Bromobenzyl compounds react selectively with phenols via the Williamson ether synthesis. An imidazolium charge-tagged bromobenzyl compound can be used to reveal phenol impurities in jet fuel by analysis via electrospray ionization mass spectrometry. The complex matrix as revealed by Cold EI GC/MS analysis is reduced to a few simple sets of compounds in the charge-tagged ESI mass spectrum, primarily substituted phenols and thiols. Examination of jet fuels treated by different refinery methods reveals the efficacy of these approaches in removing these contaminants.

Multispectral Wavefronts Retrieval in Digital Holographic Three-Dimensional Imaging Spectrometry

NASA Astrophysics Data System (ADS)

Yoshimori, Kyu

2010-04-01

This paper deals with a recently developed passive interferometric technique for retrieving a set of spectral components of wavefronts that are propagating from a spatially incoherent, polychromatic object. The technique is based on measurement of 5-D spatial coherence function using a suitably designed interferometer. By applying signal processing, including aperture synthesis and spectral decomposition, one may obtains a set of wavefronts of different spectral bands. Since each wavefront is equivalent to the complex Fresnel hologram at a particular spectrum of the polychromatic object, application of the conventional Fresnel transform yields 3-D image of different spectrum. Thus, this technique of multispectral wavefronts retrieval provides a new type of 3-D imaging spectrometry based on a fully passive interferometry. Experimental results are also shown to demonstrate the validity of the method.

The role of aqueous leaf extract of Tinospora crispa as reducing and capping agents for synthesis of gold nanoparticles

NASA Astrophysics Data System (ADS)

Apriandanu, D. O. B.; Yulizar, Y.

2017-04-01

Environmentally friendly method for green synthesis of Au nanoparticles (AuNP) using aqueous leaf extract of Tinospora crispa (TLE) was reported. TLE has the ability for reducing and capping AuNP. Identification of active compounds in aqueous leaf extract was obtained by phytochemical analysis and Fourier transform infrared spectroscopy (FTIR). The AuNP-TLE growth was characterized using UV-Vis spectrophotometer. The particle size and the distribution of AuNP were confirmed by particle size analyzer (PSA). AuNP-TLE formation was optimized by varying the extract concentration and time of the synthesis process. UV-Vis absorption spectrum of optimum AuNP formation displayed by the surface plasmon resonance at maximum wavelength of λmax 536 nm. The PSA result showed that AuNP has size distribution of 80.60 nm and stable up to 21 days. TEM images showed that the size of the AuNP is ± 25 nm.

Synthesis and optical properties modulation of ZnO/Eu2O3 nanocable arrays

NASA Astrophysics Data System (ADS)

Yang, Lei; She, Yajuan; Zhao, Shihua; Yue, Shihai; Wang, Qian; Hu, Aiping; Zhang, Wei

2010-11-01

White-light-emitting materials have attracted considerable attention because of their applications, such as large-surface emitting devices and displays. However, simply mixing nanoparticles would result in uneven color. Nanocables are expected to improve the chemical stability and color uniformity. Herein we demonstrate the synthesis of Eu2O3/ZnO nanocable arrays embedded in anodic alumina template via a versatile, simple, and cheap method. In order to control the composition of the cable with low cost, a two-step synthesis including an electric field deposition and a sol-gel template approach is used to fabricate the nanocable. The product is investigated by x-ray powder diffraction, transmission electron microscopy, selected area electron diffraction, and photoluminescence (PL) spectrum. The results show that ordered Eu2O3/ZnO nanocable arrays with an average inside diameter of 20-40 nm and wall thickness of 20-40 nm were prepared. By adjusting the excitation wavelength, change of the emitting color of the cables from blue to white could be obtained. Energy and charge transfer were found by investigating the electronic transition and recombination in the PL process. These arrays are promising for applications in display, white phosphors, and ultraviolet detectors owing to the special optical properties. And this method may be of much significance in the synthesis of nanocables with the controllable composition.

NLTE Line Blanketed Model Atmospheres for Hot, Metal-rich White Dwarfs

NASA Astrophysics Data System (ADS)

Hubeny, I.; Lanz, T.

1993-05-01

Recent observations of some hot DA white dwarfs (Feige 24, G191 B2B - Sion et al. 1992, Ap.J. 391, L29; Vennes et al. 1992, Ap.J. 392, L27) and subsequent analyses have demonstrated that their atmospheres are contaminated with heavy metal species with appreciable abundances. So far, modeling was mostly limited to calculating synthetic spectra (usually in LTE), based on previously calculated model atmospheres that were constructed assuming a simplified chemical composition. However, in reality the metal lines may also significantly influence the temperature structure, and consequently the ionization balance of some important species. Since the effective temperature is rather high (55000 to 60000 K), the NLTE effects may be important despite the high gravity. Therefore, in order to settle the question on metal abundances of hot DA white dwarfs, we need to calculate NLTE fully line blanketed model atmospheres. Using our previously developed hybrid complete linearization/accelerated lambda iteration method, we have calculated a set of NLTE models including H, He, C, N, O, and Fe, with some 13000 lines of Fe IV, Fe V and Fe VI taken into account explicitly in model construction. The NLTE departure coefficients for all levels of Fe IV, Fe V, and Fe VI are then employed in the spectrum synthesis program SYNSPEC. In the first part of this study, we present a theoretical comparison between models computed with adding more and more opacity sources, and show how the temperature structure and synthetic spectra develop. We also discuss possible errors arising from using an inconsistent spectrum synthesis (the metals considered only in the spectrum synthesis, not in the model construction). In the second part, we compare the computed UV spectra with with available observations of Feige 24 and G191 B2B, and deduce limits for the iron abundance of these stars.

Math Interventions for Students with Autism Spectrum Disorder: A Best-Evidence Synthesis

ERIC Educational Resources Information Center

King, Seth A.; Lemons, Christopher J.; Davidson, Kimberly A.

2016-01-01

Educators need evidence-based practices to assist students with disabilities in meeting increasingly rigorous standards in mathematics. Students with autism spectrum disorder (ASD) are increasingly expected to demonstrate learning of basic and advanced mathematical concepts. This review identifies math intervention studies involving children and…

The SCERTS[TM] Model: A Comprehensive Educational Approach for Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Prizant, Barry M.; Wetherby, Amy M.; Rubin, Emily; Laurent, Amy C.; Rydell, Patrick J.

2005-01-01

A groundbreaking synthesis of developmental, relationship-based, and skill-based approaches, The SCERTS[TM] Model provides a framework for improving communication and social-emotional abilities in individuals with autism spectrum disorders (ASD) and their families. Developed by internationally recognized experts, SCERTS[TM] supports developmental…

Motor Coordination in Autism Spectrum Disorders: A Synthesis and Meta-Analysis

ERIC Educational Resources Information Center

Fournier, Kimberly A.; Hass, Chris J.; Naik, Sagar K.; Lodha, Neha; Cauraugh, James H.

2010-01-01

Are motor coordination deficits an underlying cardinal feature of Autism Spectrum Disorders (ASD)? Database searches identified 83 ASD studies focused on motor coordination, arm movements, gait, or postural stability deficits. Data extraction involved between-group comparisons for ASD and typically developing controls (N = 51). Rigorous…

Biosynthesis of silver nanoparticles using Plectranthus amboinicus leaf extract and its antimicrobial activity

NASA Astrophysics Data System (ADS)

Ajitha, B.; Ashok Kumar Reddy, Y.; Sreedhara Reddy, P.

2014-07-01

This study reports the simple green synthesis method for the preparation of silver nanoparticles (Ag NPs) using Plectranthus amboinicus leaf extract. The pathway of nanoparticles formation is by means of reduction of AgNO3 by leaf extract, which acts as both reducing and capping agents. Synthesized Ag NPs were subjected to different characterizations for studying the structural, chemical, morphological, optical and antimicrobial properties. The bright circular fringes in SAED pattern and diffraction peaks in XRD profile reveals high crystalline nature of biosynthesized Ag NPs. Morphological studies shows the formation of nearly spherical nanoparticles. FTIR spectrum confirms the existence of various functional groups of biomolecules capping the nanoparticles. UV-visible spectrum displays single SPR band at 428 nm indicating the absence of anisotropic particles. The synthesized Ag NPs exhibited better antimicrobial property towards gram negative Escherichia coli and towards tested Penicillium spp. than other tested microorganisms using disc diffusion method. Finally it has proven that the synthesized bio-inspired Ag NPs have potent antimicrobial effect.

One-step synthesis and characterizations of cerium oxide nanoparticles in an ambient temperature via Co-precipitation method

NASA Astrophysics Data System (ADS)

Pujar, Malatesh S.; Hunagund, Shirajahammad M.; Desai, Vani R.; Patil, Shivaprasadgouda; Sidarai, Ashok H.

2018-04-01

We report the simple Co-precipitation method for the synthesis of Cerium oxide (CeO2) nanoparticles (NPs) in an ambient temperature. We have taken the Cerium (III) nitrate hexahydrate (Ce(NO3)3.6H2O) and Sodium hydroxide (NaOH) as the precursors. The obtained NPs were analyzed using the UV-Vis spectrophotometer, Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The obtained results signify that UV-Vis spectrum exhibited a well-defined absorption peak at 274 nm and the estimated energy gap (Eg) is 4.05 eV. The FT-IR analysis provides the supporting evidence for the presence of bonding of O-H, nitrates, alcohols and O-Ce-O vibrations. The XRD result reveals that the synthesized CeO2 NPs was crystallite with cubic phase structure and the estimated average crystallite size of CeO2 NPs using Scherer's and W-H method was significantly different due to their assumptions. Further, it is purposed to study their photocatalytic biological activities.

SimBAL: A Spectral Synthesis Approach to Analyzing Broad Absorption Line Quasar Spectra

NASA Astrophysics Data System (ADS)

Terndrup, Donald M.; Leighly, Karen; Gallagher, Sarah; Richards, Gordon T.

2017-01-01

Broad Absorption Line quasars (BALQSOs) show blueshifted absorption lines in their rest-UV spectra, indicating powerful winds emerging from the central engine. These winds are essential part of quasars: they can carry away angular momentum and thus facilitate accretion through a disk, they can distribute chemically-enriched gas through the intergalactic medium, and they may inject kinetic energy to the host galaxy, influencing its evolution. The traditional method of analyzing BALQSO spectra involves measuring myriad absorption lines, computing the inferred ionic column densities in each feature, and comparing with the output of photonionization models. This method is inefficient and does not handle line blending well. We introduce SimBAL, a spectral synthesis fitting method for BALQSOs, which compares synthetic spectra created from photoionization model results with continuum-normalized observed spectra using Bayesian model calibration. We find that we can obtain an excellent fit to the UV to near-IR spectrum of the low-redshift BALQSO SDSS J0850+4451, including lines from diverse ionization states such as PV, CIII*, SIII, Lyalpha, NV, SiIV, CIV, MgII, and HeI*.

R-Baclofen Reverses a Social Behavior Deficit and Elevated Protein Synthesis in a Mouse Model of Fragile X Syndrome

PubMed Central

Qin, Mei; Huang, Tianjian; Kader, Michael; Krych, Leland; Xia, Zengyan; Burlin, Thomas; Zeidler, Zachary; Zhao, Tingrui

2015-01-01

Background: Fragile X syndrome (FXS) is the most common known inherited form of intellectual disability and the single genomic cause of autism spectrum disorders. It is caused by the absence of a fragile X mental retardation gene (Fmr1) product, FMRP, an RNA-binding translation suppressor. Elevated rates of protein synthesis in the brain and an imbalance between synaptic signaling via glutamate and γ-aminobutyric acid (GABA) are both considered important in the pathogenesis of FXS. In a mouse model of FXS (Fmr1 knockout [KO]), treatment with R-baclofen reversed some behavioral and biochemical phenotypes. A remaining crucial question is whether R-baclofen is also able to reverse increased brain protein synthesis rates. Methods: To answer this question, we measured regional rates of cerebral protein synthesis in vivo with the L-[1-14C]leucine method in vehicle- and R-baclofen–treated wildtype and Fmr1 KO mice. We further probed signaling pathways involved in the regulation of protein synthesis. Results: Acute R-baclofen administration corrected elevated protein synthesis and reduced deficits on a test of social behavior in adult Fmr1 KO mice. It also suppressed activity of the mammalian target of rapamycin pathway, particularly in synaptosome-enriched fractions, but it had no effect on extracellular-regulated kinase 1/2 activity. Ninety min after R-baclofen treatment, we observed an increase in metabotropic glutamate receptor 5 expression in the frontal cortex, a finding that may shed light on the tolerance observed in human studies with this drug. Conclusions: Our results suggest that treatment via activation of the GABA (GABA receptor subtype B) system warrants further study in patients with FXS. PMID:25820841

Green synthesis, characterization and evaluation of biocompatibility of silver nanoparticles

NASA Astrophysics Data System (ADS)

Ahamed, Maqusood; Majeed Khan, M. A.; Siddiqui, M. K. J.; AlSalhi, Mohamad S.; Alrokayan, Salman A.

2011-04-01

Although green synthesis of silver nanoparticles (Ag NPs) by various plants and microorganisms has been reported, the potential of plants as biological materials for the synthesis of nanoparticles and their compatibility to biological systems is yet to be fully explored. In this study, we report a simple green method for the synthesis of Ag NPs using garlic clove extract as a reducing and stabilizing agent. In addition to green synthesis, biological response of Ag NPs in human lung epithelial A549 cells was also assessed. Ag NPs were rapidly synthesized using garlic clove extract and the formation of nanoparticles was observed within 30 min. The green synthesized Ag NPs were characterized using UV-vis spectrum, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), field emission transmission electron microscopy (FETEM), X-ray energy-dispersive spectroscopy (EDX) and dynamic light scattering (DLS). Characterization data demonstrated that the particles were crystalline in nature and spherical shaped with an average diameter of 12 nm. Measurements of cell viability, cell membrane integrity and intracellular production of reactive oxygen species have shown that the green synthesized Ag NPs were nontoxic to human lung epithelial A549 cells. This study demonstrated a simple, cost-effective and environmentally benign synthesis of Ag NPs with excellent biocompatibility to human lung epithelial A549 cells. This preliminary in vitro investigation needs to be followed up by future studies with various biological systems.

Synthesis of gold nanostructures with optical properties within the near-infrared window for biomedical applications

NASA Astrophysics Data System (ADS)

Garcia-Soto, Mariano de Jesus

The work reported in this dissertation describes the design and synthesis of different gold nanoshells with strong absorption coefficients at the near-infrared region (NIR) of the spectrum, and includes preliminary studies of their use for the photo-induced heating of pancreatic cancer cells and ex vivo tissues. As the emphasis was on gold nanoshells with maximum extinctions located at 800 nm, the methods explored for their synthesis led us to the preparation of silica-core and hollow gold nanoshells of improved stability, with maximum extinctions at or beyond the targeted within the near-infrared window. The synthesis of silica-core gold nanoshells was investigated first given its relevance as one of the pioneering methods to produce gold nanostructures with strong absorption and scattering coefficients in the visible and the near-infrared regions of the spectrum. By using a classical method of synthesis, we explored the aging of the precursor materials and the effect of using higher concentrations than the customary for the reduction of gold during the shell growth. We found that the aging for one week of the as-prepared or purified precursors, namely, the gold cluster suspensions, and the seeded silica particles, along with higher concentrations of gold in the plating solution, produced fully coated nanoshells of 120 nm in size with smooth surfaces and maximum extinctions around 800 nm. Additional work carried out to reduce the time and steps in the synthesis of silica-core gold nanoshells, led us to improve the seeding step by increasing the ionic strength of the cluster suspension, and also to explore the growth of gold on tin-seeded silica nanoparticles. The synthesis of hollow gold nanoshells (HGS) of with maximum extinctions at the NIR via the galvanic replacement of silver nanoparticles for gold in solution was explored next. A first method explored led us to obtain HGS with maximum extinctions between 650 and 800 nm and sizes between 30 and 80 nm from silver nanoparticles, which were grown by the addition of silver nitrate and a mild reducer. We developed a second method that led us to obtain HGS with maximum extinctions between 750 and 950 nm by adjusting the pH of the precursor solution of the silver particles without much effort or additional steps. The last part of this work consisted in demonstrating the photo-induced heating of two biological systems containing HGS. Photothermal therapy studies of immobilized PANC1 pancreas cancer cells in well-plates were carried out with functionalized HGS. We found that cells exposed to HGS remained viable after incubation. Moreover, the cells incubated with HGS modified with mercaptoundecanoic acid and folic acid turned non-viable after being irradiated with a laser at 800 nm. The other study consisted in the laser-induced heating between 750 and 1000 nm of ex vivo tissues of chicken and pork with nanoshells injected. In comparison with non-injected tissues, it was found that the temperature at the irradiated areas with HGS increased more than 10 °C. Moreover, the extent of the heated area was broader when the laser was used at wavelengths beyond 900 nm, suggesting that the heating was due to the radiation absorbed and transformed into heat primarily by the HGS and at a lesser extent by the water in the tissue.

Organic synthesis in the Smith Group: a personal selection of a dozen lessons learned at the University of Pennsylvania.

PubMed

Minbiole, Kevin P C

2016-04-01

The passionate study of the complex and ever-evolving discipline of organic synthesis over more than a four-decade span is certain to elucidate meaningful and significant lessons. Over this period, Amos B. Smith III, the Rhodes-Thompson Professor of Chemistry and Member of the Monell Chemical Senses Center at the University of Pennsylvania, has mentored well over 100 doctoral and masters students, more than 200 postdoctoral associates and numerous undergraduates, in addition to collaborating with a wide spectrum of internationally recognized scholars. His research interests, broadly stated, comprise complex molecule synthesis, the development of new, versatile and highly effective synthetic methods, bioorganic and medicinal chemistry, peptide mimicry chemistry and material science. Each area demands a high level of synthetic design and execution. United by a passion to unlock the secrets of organic synthesis, and perhaps of Nature itself, innumerable lessons have been, and continue to be, learned by the members of the Smith Group. This lead article in a Special Issue of the Journal of Antibiotics affords an opportunity to share some of those lessons learned, albeit a small selection of personal favorites.

Combustion synthesis of MgO nanoparticles using plant extract: Structural characterization and photoluminescence studies

NASA Astrophysics Data System (ADS)

Kumar, Danith; Yadav, L. S. Reddy; Lingaraju, K.; Manjunath, K.; Suresh, D.; Prasad, Daruka; Nagabhushana, H.; Sharma, S. C.; Naika, H. Raja; Chikkahanumantharayappa, Nagaraju, G.

2015-06-01

Magnesium oxide nanoparticles (MgO Nps) have been successfully synthesized via solution combustion method using Parthenium plant extract as fuel for the first time. Powder X-ray diffraction (PXRD) pattern reveal that product belongs to the cubic phase (Periclase). FTIR spectrum shows the band at 822 cm-1 indicates the formation of cubic periclase MgO. The optical band gap of MgO Nps estimated from UV -Vis spectrum was found to be in the range 5.40-5.45 eV. SEM images showed that, the product is agglomerated and particle in nature. Photoluminescence (PL) studies shows violet emission at 390 nm, blue emission at 470 nm and green emission at 550 nm. MgO Nps shows good photocatalytic activity for the degradation of methylene blue (MB) dye under UV/Sun light irradiation.

Autism Spectrum Disorders: A Research Review for School Counselors

ERIC Educational Resources Information Center

Auger, Richard W.

2013-01-01

The number of students with autism spectrum disorders (ASD) has risen significantly in recent years (CDC, 2012), and students with ASD present unique challenges to schools and school counselors. This article presents a synthesis of recent research literature related to ASD for the purpose of providing school counselors with assistance in…

Reading Comprehension Interventions for Students with Autism Spectrum Disorders: A Synthesis of Research

ERIC Educational Resources Information Center

El Zein, Farah; Solis, Michael; Vaughn, Sharon; McCulley, Lisa

2014-01-01

The authors synthesized reading intervention studies conducted between 1980 and 2012 with K-12 students identified with autism spectrum disorders (ASD). Nine single-subject design studies, one quasi-experimental study, and two single-group design studies met the criteria for inclusion. Findings from the studies indicate that modifying…

80GHz waveform generator by optical Fourier synthesis of four spectral sidebands (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fatome, Julien; Hammani, Kamal; Kibler, Bertrand; Finot, Christophe

2016-04-01

Versatile and easy to implement methods to generate arbitrary optical waveforms at high repetition rates are of considerable interest with applications in optical communications, all-optical signal processing, instrumentation systems and microwave signal manipulation. While shaping sinusoidal, Gaussian or hyperbolic secant intensity profiles is commonly achieved by means of modulators or mode-locked lasers, other pulse profiles such as parabolic, triangular or flat-top shapes still remain challenging to synthesize. In this context, several strategies were already explored. First, the linear pulse shaping is a common method to carve an initial ultrashort pulse train into the desired shape. The line-by-line shaping of a coherent frequency comb made of tens of spectral components was also investigated to generate more complex structures whereas Fourier synthesis of a few discrete frequencies spectrum was exploited to efficiently generate high-fidelity ultrafast periodic intensity profiles. Besides linear shaping techniques, several nonlinear methods were implemented to benefit from the adiabatic evolution of the intensity pulse profile upon propagation in optical fibers. Other examples of efficient methods are based on the photonic generation involving specific Mach-Zehnder modulators, microwave photonic filters as well as frequency-to-time conversion. In this contribution, we theoretically and experimentally demonstrate a new approach enabling the synthesis of periodic high-repetition rate pulses with various intensity profiles ranging from parabola to triangular and flat-top pulses. More precisely by linear phase and amplitude shaping of only four spectral lines is it possible to reach the targeted temporal profile. Indeed, tailoring the input symmetric spectrum only requires the determination of two physical parameters: the phase difference between the inner and outer spectral sidebands and the ratio between the amplitude of these sidebands. Therefore, a systematic bidimensional analysis provides the optimum parameters and also highlights that switching between the different waveforms is achieved by simply changing the spectral phase between the inner and outer sidebands. We successfully validate this concept with the generation of high-fidelity ultrafast periodic waveforms at 40 GHz by shaping with a liquid cristal on insulator a four sideband comb resulting from a phase-modulated continuous wave. In order to reach higher repetition rates, we also describe a new scenario to obtain the required initial spectrum by taking advantage of the four-wave mixing process occurring in a highly nonlinear fiber. This approach is experimentally implemented at a repetition rate of 80-GHz by use of intensity and phase measurements that stress that full-duty cycle, high-quality, triangular, parabolic or flat-top profiles are obtained in full agreement with numerical simulations. The reconfigurable property of this photonic waveform generator is confirmed. Finally, the generation of bunch of shaped pulses is investigated, as well as the impact of Brillouin backscattering.

Spectrum orbit utilization program technical manual SOUP5 Version 3.8

NASA Technical Reports Server (NTRS)

Davidson, J.; Ottey, H. R.; Sawitz, P.; Zusman, F. S.

1984-01-01

The underlying engineering and mathematical models as well as the computational methods used by the SOUP5 analysis programs, which are part of the R2BCSAT-83 Broadcast Satellite Computational System, are described. Included are the algorithms used to calculate the technical parameters and references to the relevant technical literature. The system provides the following capabilities: requirements file maintenance, data base maintenance, elliptical satellite beam fitting to service areas, plan synthesis from specified requirements, plan analysis, and report generation/query. Each of these functions are briefly described.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp.

PubMed

Thomas, Roshmi; Janardhanan, Anju; Varghese, Rintu T; Soniya, E V; Mathew, Jyothis; Radhakrishnan, E K

2014-01-01

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm - 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus.

Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp

PubMed Central

Thomas, Roshmi; Janardhanan, Anju; Varghese, Rintu T.; Soniya, E.V.; Mathew, Jyothis; Radhakrishnan, E.K.

2014-01-01

Metal nanoparticle synthesis is an interesting area in nanotechnology due to their remarkable optical, magnetic, electrical, catalytic and biomedical properties, but there needs to develop clean, non-toxic and environmental friendly methods for the synthesis and assembly of nanoparticles. Biological agents in the form of microbes have emerged up as efficient candidates for nanoparticle synthesis due to their extreme versatility to synthesize diverse nanoparticles with varying size and shape. In the present study, an eco favorable method for the biosynthesis of silver nanoparticles using marine bacterial isolate has been attempted. Very interestingly, molecular identification proved it as a strain of Ochrobactrum anhtropi. In addition, the isolate was found to have the potential to form silver nanoparticles intracellularly at room temperature within 24 h. The biosynthesized silver nanoparticles were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and scanning electron microscope (SEM). The UV-visible spectrum of the aqueous medium containing silver nanoparticles showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. The SEM and TEM micrographs revealed that the synthesized silver nanoparticles were spherical in shape with a size range from 38 nm – 85 nm. The silver nanoparticles synthesized by the isolate were also used to explore its antibacterial potential against pathogens like Salmonella Typhi, Salmonella Paratyphi, Vibrio cholerae and Staphylococcus aureus. PMID:25763025

Green Synthesis of NiFe2O4 Spinel-Structured Nanoparticles Using Hydrangea paniculata Flower Extract with Excellent Magnetic Property

NASA Astrophysics Data System (ADS)

Karunakaran, Gopalu; Jagathambal, Matheswaran; Van Minh, Nguyen; Kolesnikov, Evgeny; Kuznetsov, Denis

2018-05-01

Nickel ferrite (NiFe2O4) spinel-structured nanoparticles (NPs) were synthesized by a green synthesis approach using Hydrangea paniculata flower extract. Green synthesis of NPs was preliminary monitored by a color change. Further confirmation was carried out using different techniques. X-ray diffraction analysis confirmed the cubic crystalline system (fcc) of NiFe2O4. Energy-dispersive spectrum analysis showed the presence of iron, nickel, oxygen, and carbon. Scanning electron microscopy revealed the agglomerating nature of the NPs (30-50 nm). The specific surface area was found to be 46.73 m2/g, revealing the average size D of NPs to be 24 nm. Transmission electron microscopy confirmed the spherical, oval, and irregular shapes of the NPs with a size range between 10 nm and 45 nm, and an average size of 28 nm. The magnetization of the obtained NiFe2O4 NPs in a high magnetic field of 20 kOe was found to be 20 emu/g. The values of remanent magnetization (M r) and coercive field (H c) were found to be 1.1 emu/g and 28 Oe, respectively. In the process of magnetization reversal (with a small value of M r/M s, 0.055), NiFe2O4 NPs had a loop with low energy loss, showing that the obtained NiFe2O4 NPs were soft magnetic materials. The magnetization curve with a sigmoidal shape indicated that the obtained NiFe2O4 NPs are super-paramagnetic material. In addition, the comparison of green synthesis with the methods available in the literature proved that the green synthesis is the best method. Thus, it is clear that green synthesis is a novel eco-friendly approach for the synthesis of magnetic NiFe2O4 NPs.

Photo and biocatalytic activities along with UV protection properties on polyester fabric through green in-situ synthesis of cauliflower-like CuO nanoparticles.

PubMed

Rezaie, Ali Bashiri; Montazer, Majid; Rad, Mahnaz Mahmoudi

2017-11-01

In this paper, a facile environmentally friendly method is introduced for in-situ synthesis and fabrication of cauliflower-like CuO nanoparticles on the polyester fabric to produce photo and biocatalytic activities with UV protection properties on polyester fabric. The ash of burnt leaves and stems of Seidlitzia rosmarinus plant called Keliab was used as a natural and nontoxic alkaline source for simultaneous synthesis of CuO nanoparticles and surface modification of polyester without using any other compounds. The images of field-emission scanning electron microscopy, patterns of energy-dispersive spectroscopy, UV-visible spectrum and X-ray diffraction confirmed successful synthesis and loading of CuO nanoparticles on the polyester fabric. The treated fabrics showed very good antibacterial activities toward two pathogen bacteria including Staphylococcus aureus as a Gram-positive and Escherichia coli as a Gram-negative bacteria with no adverse effects on human dermal fibroblasts based on MTT test. The treated fabrics confirmed significant photocatalytic activity for degradation of methylene blue under sunlight, self-cleaning properties under UV light and also UV protection properties. Further a colorant effect along with an improvement in the wettability and mechanical properties of the treated fabrics were indicated. Overall, this method can be applied as a clean route for producing photo and bio active textiles protecting against UV irradiation. Copyright © 2017 Elsevier B.V. All rights reserved.

Rapid microwave assisted synthesis of YIn1-xMnxO3 blue pigments: Synthesis, microstructure and optical properties

NASA Astrophysics Data System (ADS)

Zhou, Yuncheng; Jiang, Peng; Kuang, Jianlei; Yang, Xueshan; Cao, Wenbin

2018-07-01

The YIn1-xMnxO3 (0.1 ≤x ≤ 0.5) blue pigment samples are successfully prepared through a sol-gel process followed by microwave assisted sintering process. All the samples are shown single phases in the X-ray diffraction results. In the morphology study from scanning electronic microscope, the samples are composed of loosely connected small particles. The oxidation state of Mn is confirmed to be 3 + from the results of X-ray photonelectronic scan. The optical properties are characterized by UV-Visible spectrum and UV-visible-NIR spectrum. The samples exhibit intense blue color and they show small absorption in infrared region.

NEBULAR: Spectrum synthesis for mixed hydrogen-helium gas in ionization equilibrium

NASA Astrophysics Data System (ADS)

Schirmer, Mischa

2016-08-01

NEBULAR synthesizes the spectrum of a mixed hydrogen helium gas in collisional ionization equilibrium. It is not a spectral fitting code, but it can be used to resample a model spectrum onto the wavelength grid of a real observation. It supports a wide range of temperatures and densities. NEBULAR includes free-free, free-bound, two-photon and line emission from HI, HeI and HeII. The code will either return the composite model spectrum, or, if desired, the unrescaled atomic emission coefficients. It is written in C++ and depends on the GNU Scientific Library (GSL).

Spectrum of classes of point emitters of electromagnetic wave fields.

PubMed

Castañeda, Román

2016-09-01

The spectrum of classes of point emitters has been introduced as a numerical tool suitable for the design, analysis, and synthesis of non-paraxial optical fields in arbitrary states of spatial coherence. In this paper, the polarization state of planar electromagnetic wave fields is included in the spectrum of classes, thus increasing its modeling capabilities. In this context, optical processing is realized as a filtering on the spectrum of classes of point emitters, performed by the complex degree of spatial coherence and the two-point correlation of polarization, which could be implemented dynamically by using programmable optical devices.

Improving Transition Behaviors in Students with Autism Spectrum Disorders: A Comprehensive Evaluation of Interventions in Educational Settings

ERIC Educational Resources Information Center

Lequia, Jenna; Wilkerson, Kimber L.; Kim, Sunyoung; Lyons, Gregory L.

2015-01-01

Students with autism spectrum disorders (ASD) often exhibit rigidity, which can lead to difficulties with transitions. Such difficulties can explain why students with ASD are placed in more restrictive educational environments. This review offers a quantitative synthesis of effects of interventions aimed to improve transitions of students with ASD…

Interventions to Support Social Interaction in Children with Autism Spectrum Disorders: A Systematic Review of Single Case Studies

ERIC Educational Resources Information Center

Ozuna, Jennifer; Mavridis, Alexis; Hott, Brittany L.

2015-01-01

Social interaction is a core deficit in individuals with autism spectrum disorder (ASD). Therefore, parents and teachers need effective interventions to support students with ASD. This synthesis provides a quantitative analysis of single-subject studies that examine interventions to support social interactions in children with ASD. Results suggest…

Brief Report: Whole Blood Serotonin Levels and Gastrointestinal Symptoms in Autism Spectrum Disorder

ERIC Educational Resources Information Center

Marler, Sarah; Ferguson, Bradley J.; Lee, Evon Batey; Peters, Brittany; Williams, Kent C.; McDonnell, Erin; Macklin, Eric A.; Levitt, Pat; Gillespie, Catherine Hagan; Anderson, George M.; Margolis, Kara Gross; Beversdorf, David Q.; Veenstra-VanderWeele, Jeremy

2016-01-01

Elevated whole blood serotonin levels are observed in more than 25% of children with autism spectrum disorder (ASD). Co-occurring gastrointestinal (GI) symptoms are also common in ASD but have not previously been examined in relationship with hyperserotonemia, despite the synthesis of serotonin in the gut. In 82 children and adolescents with ASD,…

Endophytic synthesis of silver chloride nanoparticles from Penicillium sp. of Calophyllum apetalum

NASA Astrophysics Data System (ADS)

Chandrappa, C. P.; Govindappa, M.; Chandrasekar, N.; Sarkar, Sonia; Ooha, Sepuri; Channabasava, R.

2016-06-01

In the present study, Penicillium species extract isolated from Calophyllum apetalum was used for the synthesis of silver nanoparticles and it was confirmed by changing the color of the silver nitrate UV-Vis spectrum. The synthesized nanoparticles have been characterized by biophysical techniques such as scanning electron microscopy and x-ray diffraction.

One-step synthesis of highly-biocompatible spherical gold nanoparticles using Artocarpus heterophyllus Lam. (jackfruit) fruit extract and its effect on pathogens.

PubMed

Basavegowda, Nagaraj; Dhanya Kumar, Gowri; Tyliszczak, Bozena; Wzorek, Zbigniew; Sobczak-Kupiec, Agnieszka

2015-01-01

Novel approaches for the synthesis of gold nanoparticles (AuNPs) are of great importance due to its vast spectrum of applications in diverse fields, including medical diagnostics and therapeutics. Te presented study reports the successful AuNPs' synthesis using Artocarpus heterophyllus Lam. extract, and provides detailed characterization and evaluation of its antibacterial potential. The aim was to develop a cost-effective and environmentally friendly synthesis method of gold nanoparticles using aqueous fruit extract of Artocarpus heterophyllus Lam. as a reducing and capping agent, which has proven activity against human pathogens, such as microbial species E.coli and Streptobacillus sps. Characterizations were carried out using ultraviolet-visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), energy dispersive X-ray and Fourier-Transform infra-red spectroscopy (FT-IR). SEM images showed the formation of gold nanoparticles with an average size of 20-25 nm. Spectra collected while infra-red analysis contained broad peaks in ranges from 4000-400 cm -1 . It can be concluded that the fruit of Artocarpus heterophyllus Lam. can be good source for synthesis of gold nanoparticles which showed antimicrobial activity against investigated microbes, in particul E. coli, and Streptobacillus. An important outcome of this study will be the development of value-added products from the medicinal plant Artocarpus heterophyllus Lam. for the biomedical and nanotechnology-based industries.

Synthesis and characterization of magnetite-maghemite nanoparticles obtained by the high-energy ball milling method

NASA Astrophysics Data System (ADS)

Velásquez, A. A.; Marín, C. C.; Urquijo, J. P.

2018-03-01

We present the process of synthesis and characterization of magnetite-maghemite nanoparticles by the ball milling method. The particles were synthesized in a planetary ball mill equipped with vials and balls of tempered steel, employing dry and wet conditions. For dry milling, we employed microstructured analytical-grade hematite (α-Fe2O3), while for wet milling, we mixed hematite and deionized water. Milling products were characterized by X-ray diffraction, transmission electron microscopy, room temperature Mössbauer spectroscopy, vibrating sample magnetometry, and atomic absorption spectroscopy. The Mössbauer spectrum of the dry milling product was well fitted with two sextets of hematite, while the spectrum of the wet milling product was well fitted with three sextets of spinel phase. X-ray measurements confirmed the phases identified by Mössbauer spectroscopy in both milling conditions and a reduction in the crystallinity of the dry milling product. TEM measurements showed that the products of dry milling for 100 h and wet milling for 24 h consist of aggregates of nanoparticles distributed in size, with mean particle size of 10 and 15 nm, respectively. Magnetization measurements of the wet milling product showed little coercivity and a saturation magnetization around 69 emu g-1, characteristic of a nano-spinel system. Atomic absorption measurements showed that the chromium contamination in the wet milling product is approximately two orders of magnitude greater than that found in the dry milling product for 24 h, indicating that the material of the milling bodies, liberated more widely in wet conditions, plays an important role in the conversion hematite-spinel phase.

Combustion synthesis of MgO nanoparticles using plant extract: Structural characterization and photoluminescence studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Danith; Chikkahanumantharayappa; Yadav, L. S. Reddy

Magnesium oxide nanoparticles (MgO Nps) have been successfully synthesized via solution combustion method using Parthenium plant extract as fuel for the first time. Powder X-ray diffraction (PXRD) pattern reveal that product belongs to the cubic phase (Periclase). FTIR spectrum shows the band at 822 cm{sup −1} indicates the formation of cubic periclase MgO. The optical band gap of MgO Nps estimated from UV –Vis spectrum was found to be in the range 5.40–5.45 eV. SEM images showed that, the product is agglomerated and particle in nature. Photoluminescence (PL) studies shows violet emission at 390 nm, blue emission at 470 nm and green emissionmore » at 550 nm. MgO Nps shows good photocatalytic activity for the degradation of methylene blue (MB) dye under UV/Sun light irradiation.« less

Synthesis, growth and characterization of 3-nitroacetanilide—A new organic nonlinear optical crystal by Bridgman technique

NASA Astrophysics Data System (ADS)

Lenin, M.; Ramasamy, P.

2008-10-01

Single crystals of 3-nitroacetanilide, an organic nonlinear optical material has been grown by the Bridgman-Stockbarger method. The single crystal X-ray diffraction (XRD) data revealed the noncentrosymmetric crystal structure, which is an essential criterion for second harmonic generation. The crystalline nature of the grown crystals was confirmed using powder XRD techniques. The functional group of the compound is identified by FTIR spectrum. The thermal stability and its tendency to grow as single crystal in solution and in melt have been identified for the new title compound. The UV-vis spectrum of mNAA shows the lower optical cut off at 400 nm and was transparent in the visible region. The second harmonic generation efficiency was found using Kurtz powder technique. The dielectric constant and dielectric loss of the crystal were measured as a function of frequency and temperature, and the results are discussed.

MOF-5 decorated hierarchical ZnO nanorod arrays and its photoluminescence

NASA Astrophysics Data System (ADS)

Zhang, Yinmin; Lan, Ding; Wang, Yuren; Cao, He; Jiang, Heng

2011-04-01

The strategy to manipulate nanoscale materials into well-organized hierarchical architectures is very important to both material synthesis and nanodevice applications. Here, nanoscale MOF-5 crystallites were successfully fabricated onto ordered hierarchical ZnO arrays based on aqueous chemical synthesis and molecule self-assembly technology guided room temperature diffusion method, which has the advantages of energy saving and simple operation. The structures and morphologies of the samples were performed by X-ray powder diffraction and field emission scanning electronic microscopy. The MOF-5 crystallites have good quality and bind well to the hexagonal-patterned ZnO arrays. The photoluminescence spectrum shows that the emission of hybrid MOF-5-ZnO films displays a blue shift in green emission and intensity reduction in UV emission. This ordered hybrid semiconductor material is expected to exploit the great potentiality in sensors, micro/nanodevices, and screen displays.

Pulsed plasma chemical synthesis of SixCyOz composite nanopowder

NASA Astrophysics Data System (ADS)

Kholodnaya, G.; Sazonov, R.; Ponomarev, D.; Remnev, G.

2017-05-01

SixCyOz composite nanopowder with an average size of particles about 10-50 nm was produced using the pulsed plasma chemical method. The experiments on the synthesis of nanosized composite were carried out using a TEA-500 pulsed electron accelerator. To produce a composite, SiCl4, O2, and CH4 were used. The major part of experiments was conducted using a plasma chemical reactor (quartz, 140 mm diameter, 6 l volume). The initial reagents were injected into the reactor, then a pulsed electron beam was injected which initiated the chemical reactions whose products were the SixCyOz composite nanopowder. To define the morphology of the particles, the JEOL-II-100 transmission electron microscope (TEM) with an accelerating voltage of 100 kV was used. The substances in the composition of the composite nanopowder were identified using the infrared absorption optical spectrum. To conduct this analysis, the Nicolet 5700 FT-IR spectrometer was used.

Novel aldehyde and thiosemicarbazone derivatives: Synthesis, spectroscopic characterization, structural studies and molecular docking studies

NASA Astrophysics Data System (ADS)

Karakurt, Tuncay; Tahtaci, Hakan; Subasi, Nuriye Tuna; Er, Mustafa; Ağar, Erbil

2016-12-01

In this study our purpose is that, synthesis and characterization of compounds containing the aldehyde and thiosemicarbazone groups and comparison of the theoretical results with the experimental results. The structures of all synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analyses techniques. The structure of compound (4) (C9H8N4O2S) was also elucidated by X-ray diffraction analysis. In addition, the theoretical IR spectrum, 1H NMR and 13C NMR chemical shift values, frontier molecular orbital values (FMO) of these molecules were analyzed by using Becke-3- Lee-Yang-Parr (B3LYP) method with LanL2DZ basis set. Finally, molecular docking studies were performed on synthesized compounds using the 4DKI beta-lactam protein structure to determine the potential binding mode of inhibitors.

Searching for the optimal synthesis parameters of InP/CdxZn1-xSe quantum dots when combined with a broad band phosphor to optimize color rendering and efficacy of a hybrid remote phosphor white LED

NASA Astrophysics Data System (ADS)

Ryckaert, Jana; Correia, António; Smet, Kevin; Tessier, Mickael D.; Dupont, Dorian; Hens, Zeger; Hanselaer, Peter; Meuret, Youri

2017-09-01

Combining traditional phosphors with a broad emission spectrum and non-scattering quantum dots with a narrow emission spectrum can have multiple advantages for white LEDs. It allows to reduce the amount of scattering in the wavelength conversion element, increasing the efficiency of the complete system. Furthermore, the unique possibility to tune the emission spectrum of quantum dots allows to optimize the resulting LED spectrum in order to achieve optimal color rendering properties for the light source. However, finding the optimal quantum dot properties to achieve optimal efficacy and color rendering is a non-trivial task. Instead of simply summing up the emission spectra of the blue LED, phosphor and quantum dots, we propose a complete simulation tool that allows an accurate analysis of the final performance for a range of different quantum dot synthesis parameters. The recycling of the reflected light from the wavelength conversion element by the LED package is taken into account, as well as the re-absorption and the associated red-shift. This simulation tool is used to vary two synthesis parameters (core size and cadmium fraction) of InP/CdxZn1-xSe quantum dots. We find general trends for the ideal quantum dot that should be combined with a specific YAG:Ce broad band phosphor to obtain optimal efficiency and color rendering for a white LED with a specific pumping LED and recycling cavity, with a desired CCT of 3500K.

Effectiveness of Gluten-Free and Casein-Free Diets for Individuals with Autism Spectrum Disorders: An Evidence-Based Research Synthesis

ERIC Educational Resources Information Center

Zhang, Jie; Mayton, Michael R.; Wheeler, John J.

2013-01-01

In order to better assist practitioners and better serve persons with autism spectrum disorders (ASD) and their families, it is vital for professionals to systematically evaluate the existing body of literature and synthesize its scientific evidence, so that the efficacy of research can be translated to evidence-based practices (EBPs) (Wheeler,…

Biosynthesis of silver nanoparticles using Plectranthus amboinicus leaf extract and its antimicrobial activity.

PubMed

Ajitha, B; Ashok Kumar Reddy, Y; Sreedhara Reddy, P

2014-07-15

This study reports the simple green synthesis method for the preparation of silver nanoparticles (Ag NPs) using Plectranthus amboinicus leaf extract. The pathway of nanoparticles formation is by means of reduction of AgNO3 by leaf extract, which acts as both reducing and capping agents. Synthesized Ag NPs were subjected to different characterizations for studying the structural, chemical, morphological, optical and antimicrobial properties. The bright circular fringes in SAED pattern and diffraction peaks in XRD profile reveals high crystalline nature of biosynthesized Ag NPs. Morphological studies shows the formation of nearly spherical nanoparticles. FTIR spectrum confirms the existence of various functional groups of biomolecules capping the nanoparticles. UV-visible spectrum displays single SPR band at 428 nm indicating the absence of anisotropic particles. The synthesized Ag NPs exhibited better antimicrobial property towards gram negative Escherichia coli and towards tested Penicillium spp. than other tested microorganisms using disc diffusion method. Finally it has proven that the synthesized bio-inspired Ag NPs have potent antimicrobial effect. Copyright © 2014 Elsevier B.V. All rights reserved.

Information analysis of hyperspectral images from the hyperion satellite

NASA Astrophysics Data System (ADS)

Puzachenko, Yu. G.; Sandlersky, R. B.; Krenke, A. N.; Puzachenko, M. Yu.

2017-07-01

A new method of estimating the outgoing radiation spectra data obtained from the Hyperion EO-1 satellite is considered. In theoretical terms, this method is based on the nonequilibrium thermodynamics concept with corresponding estimates of the entropy and the Kullbak information. The obtained information estimates make it possible to assess the effective work of the landscape cover both in general and for its various types and to identify the spectrum ranges primarily responsible for the information increment and, accordingly, for the effective work. The information is measured in the frequency band intervals corresponding to the peaks of solar radiation absorption by different pigments, mesophyll, and water to evaluate the system operation by their synthesis and moisture accumulation. This method is assumed to be effective in investigation of ecosystem functioning by hyperspectral remote sensing.

Optimization of low cost, non toxic, earth abundant p-type Cu2SnS3 thin film for Photovoltaic application

NASA Astrophysics Data System (ADS)

Chaudhari, J. J.; Patel, S.; Joshi, U. S.

2016-09-01

Cu2SnS3 (CTS) is one of promising candidate as an absorber material for thin film solar cell. Because of relatively higher prize of Indium and hazardous environmental impact of processing of Gallium, CTS is suitable alternative candidate to Cu2SnS3 (CIGS) based solar cell as its constituent elements such as copper, tin and sulphur are abundantly available in earth's crust. CTS is ternary semiconductor and its energy band gap is 1.5eV, which is perfectly matched with solar energy spectrum for maximum transfer of solar energy into electrical energy through photovoltaic action. The primary methods for the synthesis of CTS are Thermal evaporation, electrochemical, sputtering and wet chemical methods. Here in this paper we have optimized a low cost non-vacuum solution process method for the synthesis of CTS without any external sulfurization. The X-ray diffraction studies showed the formation of phase with the peaks corresponding to (112), (220) and (312) planes. Chemical Solution Deposition (CSD) for the synthesis of CTS is suitable for large area deposition and it includes several routes like solvothermal methods, direct liquid coating and nano ink based technique. The metal Chloride salts and thiourea is used as a source of sulphur to synthesize CTS solution and homogeneous thin films of CTS deposited on glass substrate using spin coating method. Use of abrasive solvent like hydrazine and hydrogen sulphide gas which are used to synthesize CTS thin film have detrimental effect on environment, we report eco friendly solvent based approach to synthesize CTS at low temperature 200 °C.

Cr:SnO2 thin films-synthesis and characterization

NASA Astrophysics Data System (ADS)

Varghese, Anitta Rose; B. Bhadrapriya, C.; Amarendra, G.; Hussain, Shamima

2018-04-01

Thin films of pure and Chromium doped SnO2 were synthesized using sol-gel method by spin coating technique. XRD studies confirmed the formation of tetragonal structure for SnO2 thin films. Variations in peak width and position were identified with doping. The optical band gap of the undoped films was found to be 3.8eV and varied with doping. Raman spectrum gave signature peaks of Sn-O and Cr-O bonds for undoped and doped films. The uniformity of the samples and formation of aggregates were observed from FESEM analysis.

Synthesis and Characterization of CeO2 Nanoparticles via Solution Combustion Method for Photocatalytic and Antibacterial Activity Studies

PubMed Central

Ravishankar, Thammadihalli Nanjundaiah; Ramakrishnappa, Thippeswamy; Nagaraju, Ganganagappa; Rajanaika, Hanumanaika

2015-01-01

CeO2 nanoparticles have been proven to be competent photocatalysts for environmental applications because of their strong redox ability, nontoxicity, long-term stability, and low cost. We have synthesized CeO2 nanoparticles via solution combustion method using ceric ammonium nitrate as an oxidizer and ethylenediaminetetraacetic acid (EDTA) as fuel at 450 °C. These nanoparticles exhibit good photocatalytic degradation and antibacterial activity. The obtained product was characterized by various techniques. X-ray diffraction data confirms a cerianite structure: a cubic phase CeO2 having crystallite size of 35 nm. The infrared spectrum shows a strong band below 700 cm−1 due to the Ce−O−Ce stretching vibrations. The UV/Vis spectrum shows maximum absorption at 302 nm. The photoluminescence spectrum shows characteristic peaks of CeO2 nanoparticles. Scanning electron microscopy (SEM) images clearly show the presence of a porous network with a lot of voids. From transmission electron microscopy (TEM) images, it is clear that the particles are almost spherical, and the average size of the nanoparticles is found to be 42 nm. CeO2 nanoparticles exhibit photocatalytic activity against trypan blue at pH 10 in UV light, and the reaction follows pseudo first-order kinetics. Finally, CeO2 nanoparticles also reduce CrVI to CrIII and show antibacterial activity against Pseudomonas aeruginosa. PMID:25969812

How Do Parents Manage Irritability, Challenging Behaviour, Non-Compliance and Anxiety in Children with Autism Spectrum Disorders? A Meta-Synthesis

ERIC Educational Resources Information Center

O'Nions, Elizabeth; Happé, Francesca; Evers, Kris; Boonen, Hannah; Noens, Ilse

2018-01-01

Although there is increasing research interest in the parenting of children with ASD, at present, little is known about everyday strategies used to manage problem behaviour. We conducted a meta-synthesis to explore what strategies parents use to manage irritability, non-compliance, challenging behaviour and anxiety in their children with ASD.…

Synthesis of bismuth titanate (BTO) nanopowder and fabrication of microstrip rectangular patch antenna

NASA Astrophysics Data System (ADS)

Thiruramanathan, P.; Sharma, Sanjeev K.; Sankar, S.; Sankar Ganesh, R.; Marikani, A.; Kim, Deuk Young

2016-12-01

The bismuth titanate (Bi4Ti3O12) or BTO nanopowder was synthesized from the combustion method and fabricated a microstrip rectangular patch antenna (MPA). The crystal structure and lattice spacing of BTO were evaluated from XRD, TEM, and SAED analysis. The crystal structure of BTO (annealed at 900 °C) was observed to be the orthorhombic phase with fcc lattice. The microstructure of BTO nanoparticles was confirmed the spherical and hexagonal shapes, which were slightly agglomerated due to the lack of stabilizing surfactants. The presence of weak and wide bands in Raman spectrum quantified the mechanical compressions to the uniform directions of elongated lattice constants and tensions to the lattice constriction of crystalline bismuth titanate. To fabricate the MPA, pellets of BTO nanopowder were prepared by applying the uniaxial pressure in the dimension of 1.5 mm thickness and 8 mm diameter. These pellets were formed a densely packed structure close to the theoretical density. The coercivity and remanence polarization of BTO ceramics increased as the applied field increased. The inexpensive combustion synthesis method of BTO nanopowder showed the high dielectric constant (ɛ' = 450) and low dielectric loss (tan δ = 0.98), which has a potential implication of the cost-effectiveness in the field of miniaturized microelectronics. The synthesis and measurements of BTO ceramics are found to be suitable for wireless communication systems.

Nonequilibrium-Plasma-Synthesized ZnO Nanocrystals with Plasmon Resonance Tunable via Al Doping and Quantum Confinement.

PubMed

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.

A new Schiff base compound N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone): synthesis, experimental and theoretical studies on its crystal structure, FTIR, UV-visible, 1H NMR and 13C NMR spectra.

PubMed

Saheb, Vahid; Sheikhshoaie, Iran

2011-10-15

The Schiff base compound, N,N'-(2,2-dimetylpropane)-bis(dihydroxylacetophenone) (NDHA) is synthesized through the condensation of 2-hydroxylacetophenone and 2,2-dimethyl 1,3-amino propane in methanol at ambient temperature. The yellow crystalline precipitate is used for X-ray single-crystal determination and measuring Fourier transform infrared (FTIR), UV-visible, (1)H NMR and (13)C NMR spectra. Electronic structure calculations at the B3LYP, PBEPBE and PW91PW91 levels of theory are performed to optimize the molecular geometry and to calculate the FTIR, (1)H NMR and (13)C NMR spectra of the compound. Time-dependent density functional theory (TDDFT) method is used to calculate the UV-visible spectrum of NDHA. Vibrational frequencies are determined experimentally and compared with those obtained theoretically. Vibrational assignments and analysis of the fundamental modes of the compound are also performed. All theoretical methods can well reproduce the structure of the compound. The (1)H NMR and (13)C NMR chemical shifts calculated by all DFT methods are consistent with the experimental data. However, the NMR shielding tensors computed at the B3LYP/6-31+G(d,p) level of theory are in better agreement with experimental (1)H NMR and (13)C NMR spectra. The electronic absorption spectrum calculated at the B3LYP/6-31+G(d,p) level by using TD-DFT method is in accordance with the observed UV-visible spectrum of NDHA. In addition, some quantum descriptors of the molecule are calculated and conformational analysis is performed and the results were compared with the crystallographic data. Copyright © 2011 Elsevier B.V. All rights reserved.

UV radiation, vitamin D, and cancer: how to measure the vitamin D synthetic capacity of UV sources?

NASA Astrophysics Data System (ADS)

Terenetskaya, Irina; Orlova, Tatiana

2005-09-01

UV irradiation is widely used in phototherapy. Regardless of the fact that UV overexposure is liable to cause adverse health effect, in appropriate doses UV radiation initiates synthesis of vitamin D in skin that is absolutely essential for human health. As it proved, most people in northern industrial countries have a level of vitamin D in their bodies that is insufficient for optimum health, especially in winter. These low levels of vitamin D are now known to be associated with a wide spectrum of serious disease much of which leads on to premature death. The diseases associated with D deficiency involve more than a dozen types of cancer including colon, breast and prostate, as well as the classic bone diseases: rickets, osteoporosis and osteomalacia. Irradiation with artificial UV sources can prevent the vitamin D deficiency. However, in view of different irradiation spectra of UV lamps, their ability to initiate vitamin D synthesis is different. The reliable method based on an in vitro model of vitamin D synthesis has been developed for direct measurement in situ of the vitamin D synthetic capacity of artificial UV sources during a phototherapeutic procedure

Wideband dichroic-filter design for LED-phosphor beam-combining

DOEpatents

Falicoff, Waqidi

2010-12-28

A general method is disclosed of designing two-component dichroic short-pass filters operable for incidence angle distributions over the 0-30.degree. range, and specific preferred embodiments are listed. The method is based on computer optimization algorithms for an N-layer design, specifically the N-dimensional conjugate-gradient minimization of a merit function based on difference from a target transmission spectrum, as well as subsequent cycles of needle synthesis for increasing N. A key feature of the method is the initial filter design, upon which the algorithm proceeds to iterate successive design candidates with smaller merit functions. This initial design, with high-index material H and low-index L, is (0.75 H, 0.5 L, 0.75 H)^m, denoting m (20-30) repetitions of a three-layer motif, giving rise to a filter with N=2 m+1.

HR 7098: a new cool HgMN star ?

NASA Astrophysics Data System (ADS)

Monier, R.; Gebran, M.; Royer, F.; Kılıcoǧlu, T.

2017-12-01

Using one archival high dispersion high quality spectrum of HR 7098 (A0V) obtained with the échelle spectrograph SOPHIE at Observatoire de Haute Provence, we show that this star is not a superficially normal A0V star as hitherto thought. The model atmosphere and spectrum synthesis modeling of the spectrum of HR 7098 reveals real departures of its abundances from the solar composition. We report here on our first determinations of the elemental abundances of 35 elements in the atmosphere of HR 7098. Helium and Carbon are underabundant whereas the very heavy elements are overabundant in HR 7098.

The flat bottomed lines of Vega

NASA Astrophysics Data System (ADS)

Monier, R.; Gebran, M.; Royer, F.; Kılıcoǧlu, T.

2017-12-01

Using one high dispersion high quality spectrum of Vega (HR7001, A0V) obtained with the échelle spectrograph SOPHIE at Observatoire de Haute Provence, we have measured the centroids of 149 flat bottomed lines. The model atmosphere and spectrum synthesis modeling of the spectrum of Vega allows us to provide identifications for all these lines. Most of these lines are due to C I, O I, Mg I, Al I, Ca I, Sc II,Ti II, Cr I, Cr II, Mn I, Fe I, Fe II, Sr II, Ba II, the large majority being due to neutral species, in particular Fe I.

Quantum-behaved particle swarm optimization for the synthesis of fibre Bragg gratings filter

NASA Astrophysics Data System (ADS)

Yu, Xuelian; Sun, Yunxu; Yao, Yong; Tian, Jiajun; Cong, Shan

2011-12-01

A method based on the quantum-behaved particle swarm optimization algorithm is presented to design a bandpass filter of the fibre Bragg gratings. In contrast to the other optimization algorithms such as the genetic algorithm and particle swarm optimization algorithm, this method is simpler and easier to implement. To demonstrate the effectiveness of the QPSO algorithm, we consider a bandpass filter. With the parameters the half the bandwidth of the filter 0.05 nm, the Bragg wavelength 1550 nm, the grating length with 2cm is divided into 40 uniform sections and its index modulation is what should be optimized and whole feasible solution space is searched for the index modulation. After the index modulation profile is known for all the sections, the transfer matrix method is used to verify the final optimal index modulation by calculating the refection spectrum. The results show the group delay is less than 12ps in band and the calculated dispersion is relatively flat inside the passband. It is further found that the reflective spectrum has sidelobes around -30dB and the worst in-band dispersion value is less than 200ps/nm . In addition, for this design, it takes approximately several minutes to find the acceptable index modulation values with a notebook computer.

Toward optimized light utilization in nanowire arrays using scalable nanosphere lithography and selected area growth.

PubMed

Madaria, Anuj R; Yao, Maoqing; Chi, Chunyung; Huang, Ningfeng; Lin, Chenxi; Li, Ruijuan; Povinelli, Michelle L; Dapkus, P Daniel; Zhou, Chongwu

2012-06-13

Vertically aligned, catalyst-free semiconducting nanowires hold great potential for photovoltaic applications, in which achieving scalable synthesis and optimized optical absorption simultaneously is critical. Here, we report combining nanosphere lithography (NSL) and selected area metal-organic chemical vapor deposition (SA-MOCVD) for the first time for scalable synthesis of vertically aligned gallium arsenide nanowire arrays, and surprisingly, we show that such nanowire arrays with patterning defects due to NSL can be as good as highly ordered nanowire arrays in terms of optical absorption and reflection. Wafer-scale patterning for nanowire synthesis was done using a polystyrene nanosphere template as a mask. Nanowires grown from substrates patterned by NSL show similar structural features to those patterned using electron beam lithography (EBL). Reflection of photons from the NSL-patterned nanowire array was used as a measure of the effect of defects present in the structure. Experimentally, we show that GaAs nanowires as short as 130 nm show reflection of <10% over the visible range of the solar spectrum. Our results indicate that a highly ordered nanowire structure is not necessary: despite the "defects" present in NSL-patterned nanowire arrays, their optical performance is similar to "defect-free" structures patterned by more costly, time-consuming EBL methods. Our scalable approach for synthesis of vertical semiconducting nanowires can have application in high-throughput and low-cost optoelectronic devices, including solar cells.

Frequency-Dependent Blanking with Digital Linear Chirp Waveform Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Doerry, Armin Walter; Andrews, John M.

2014-07-01

Wideband radar systems, especially those that operate at lower frequencies such as VHF and UHF, are often restricted from transmitting within or across specific frequency bands in order to prevent interference to other spectrum users. Herein we describe techniques for notching the transmitted spectrum of a generated and transmitted radar waveform. The notches are fully programmable as to their location, and techniques are given that control the characteristics of the notches.

In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent

PubMed Central

Escárcega-González, Carlos Enrique; Garza-Cervantes, JA; Vázquez-Rodríguez, A; Montelongo-Peralta, Liliana Zulem; Treviño-González, MT; Díaz Barriga Castro, E; Saucedo-Salazar, EM; Chávez Morales, RM; Regalado Soto, DI; Treviño González, FM; Carrazco Rosales, JL; Cruz, Rocío Villalobos; Morones-Ramírez, José Rubén

2018-01-01

Introduction One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. Purpose In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. Materials and methods The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet–visible, and Fourier transform infrared. Results We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, and a clinical multidrug-resistant strain of P. aeruginosa) and Gram-positive (Bacillus subtilis) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Conclusion Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains. PMID:29713166

Genetics Home Reference: phosphoglycerate dehydrogenase deficiency

MedlinePlus

... on PubMed Tabatabaie L, Klomp LW, Berger R, de Koning TJ. L-serine synthesis in the central ... Gozalbo ME, Spaapen LJ, Haagen AA, Dorland L, de Koning TJ. Expanding the clinical spectrum of 3- ...

Development of a good-quality speech coder for transmission over noisy channels at 2.4 kb/s

NASA Astrophysics Data System (ADS)

Viswanathan, V. R.; Berouti, M.; Higgins, A.; Russell, W.

1982-03-01

This report describes the development, study, and experimental results of a 2.4 kb/s speech coder called harmonic deviations (HDV) vocoder, which transmits good-quality speech over noisy channels with bit-error rates of up to 1%. The HDV coder is based on the linear predictive coding (LPC) vocoder, and it transmits additional information over and above the data transmitted by the LPC vocoder, in the form of deviations between the speech spectrum and the LPC all-pole model spectrum at a selected set of frequencies. At the receiver, the spectral deviations are used to generate the excitation signal for the all-pole synthesis filter. The report describes and compares several methods for extracting the spectral deviations from the speech signal and for encoding them. To limit the bit-rate of the HDV coder to 2.4 kb/s the report discusses several methods including orthogonal transformation and minimum-mean-square-error scalar quantization of log area ratios, two-stage vector-scalar quantization, and variable frame rate transmission. The report also presents the results of speech-quality optimization of the HDV coder at 2.4 kb/s.

Green synthesis and third-order nonlinear optical properties of 6-(9H-carbazol-9-yl) hexyl acetate

NASA Astrophysics Data System (ADS)

Chen, Baili; Geng, Feng; Luo, Xuan; Zhong, Quanjie; Zhang, Qingjun; Fang, Yu; Huang, Chuanqun; Yang, Ruizhuang; Shao, Ting; Chen, Shufan

2016-10-01

An extremely simple and green approach for the synthesis of photoelectric material 6-(9H-carbazol-9-yl) hexy-acetate (CHA) has been described in detail. The molecular structure of CHA was identified with Fourier transform infrared (FT-IR) spectra and 1H Nuclear Magnetic Resonance (1H NMR) spectroscopy. The optical absorption of CHA was recorded using ultraviolet-visible (UV-vis) spectrum. Notably, the reaction was accomplished in water medium instead of traditional toxic solvents (e.g., benzene and chloroform). The yield of CHA is up to 99%, which is increased by 13% compared with the traditional method. The approach developed by us makes it possible to achieve commercial production of CHA. Moreover, the thermal stability of CHA was studied with thermogravimetric (TG) and derivative thermogravimetric (DTG) method. The third-order nonlinear optical (NLO) properties of CHAn (obtained by new method) and CHAt (obtained by traditional method) have been studied by a Z-scan technique at 440 nm. The thermal decomposition temperature is above 200 °C. The third-order NLO of CHAn and CHAt are the same. The third-order NLO susceptibility χ (3) and two photon Figures of Merit (FOMs) of CHA are 1.58 × 10-8 (esu) and 4.55, respectively. The results reveal that CHA may be a promising candidate for all-optical switching application.

Synthesis, structure and characterization of a hybrid centrosymmetric material (4-dimethylaminopyridinium nitrate gallic acid monohydrate) well-designed for non-linear optics

NASA Astrophysics Data System (ADS)

Ennaceur, Nasreddine; Jalel, Boutheina; Henchiri, Rokaya; Cordier, Marie; Ledoux-Rak, Isabelle

2018-01-01

Hybrid material: 4-Dimethylaminopyridinium nitrate gallic acid monohydrate abbreviated DNGA monohydrate has been successfully synthesized by slow evaporation method at room temperature. X-ray diffraction (XRD) on a single crystal showed that the latter was crystallized in P-1 space group. Likewise, thermal analyses demonstrated the stability of our crystal up to 80 °C. Besides, the analysis of the infrared spectrum (FTIR), allowed us to confirm the presence of the different groups present in the structure. Furthermore, by studying the UV-Visible spectrum, the transparency of our crystal was proven. Despite the fact that of having a centrosymmetric structure, the nonlinear optical properties of our single crystal, which was tested by Kurtz-Perry technique, proved that its second harmonic generation efficiency was 1.22 times more than that of KDP (potassium dihydrogen phosphate) single crystal. This nonlinear optical behavior of the studied compound was also determined through the calculations of polarizability and first hyperpolarizability values.

Spectrum synthesis of the Type Ia supernovae SN 1992A and SN 1981B

NASA Technical Reports Server (NTRS)

Nugent, Peter; Baron, E.; Hauschildt, Peter H.; Branch, David

1995-01-01

We present non-local thermodynamic equilibrium (non-LTE) synthetic spectra for the Type Ia supernovae SN 1992A and SN 1981B, near maximum light. At this epoch both supernovae were observed from the UV through the optical. This wide spectral coverage is essential for determining the density structure of a SN Ia. Our fits are in good agreement with observation and provide some insight as to the differences between these supernovae. We also discuss the application of the expanding photosphere method to SNe Ia which gives a distance that is independent of those based on the decay of Ni-56 and Cepheid variable stars.

Synthesis of novel thiol-functionalized mesoporous silica nanorods and their sorbent properties on heavy metals

NASA Astrophysics Data System (ADS)

Chen, Xi; Cai, Qiang; Sun, Lin-Hao; Zhang, Wei; Jiang, Xing-Yu

2012-09-01

Novel thiol-functionalized mesoporous silica nanorods (MSNRs) were synthesized through a base co-condensation method, in which two organoalkoxysilanes, tetraethoxylsilane (TEOS) and bis[3-(triethoxysilyl)propyl]tetrasulfide (TESPT), were used as silica precursors simultaneously. TESPT was firstly used for both morphology control and inner surface functionalization of mesoporous silica hybrid materials. The microstructures as well as porous character of the MSNRs were characterized by means of SEM, XRD, TEM and N2 sorption measurements. Infrared spectrum analysis and heavy metal ions (Ag+ and Cd2+) adsorption measurements were carried out to confirm the functionalized framework of MSNRs.

Percentage of different aluminum doping influence the morphological and optical properties of ZnO nanostructured growth for sensor application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, R., E-mail: ruziana12@gmail.com; NANO-SciTech Centre, Institue of Science, Universiti Teknologi MARA, 40450 Shah Alam, Selangor; Faculty of Applied Sciences, Universiti Teknologi MARA Pahang, 26400 Bandar Tun Razak Jengka, Pahang

In this work, Zinc Oxide (ZnO) with different aluminum (Al) doping percentage was synthesis by sol gel immersion method. Al doped ZnO at various doping percentage from 1, 2, 3, 4 and 5. It was found that with different Al percentage influence the morphological and optical properties of ZnO growth. Field Emission Scanning Electron Microscope (FESEM) image showed the use of different Al doping causes the difference in geometry and size of ZnO nanorods growth. Based on UV-Vis spectroscopy, the transmittance at 1% Al doping has the highest spectrum.

Mutation screening of melatonin-related genes in patients with autism spectrum disorders

PubMed Central

2010-01-01

Background One consistent finding in autism spectrum disorders (ASD) is a decreased level of the pineal gland hormone melatonin and it has recently been demonstrated that this decrease to a large extent is due to low activity of the acetylserotonin O-methyltransferase (ASMT), the last enzyme in the melatonin synthesis pathway. Moreover, mutations in the ASMT gene have been identified, including a splice site mutation, that were associated with low ASMT activity and melatonin secretion, suggesting that the low ASMT activity observed in autism is, at least partly, due to variation within the ASMT gene. Methods In the present study, we have investigated all the genes involved in the melatonin pathway by mutation screening of AA-NAT (arylalkylamine N-acetyltransferase), ASMT, MTNR1A, MTNR1B (melatonin receptor 1A and 1B) and GPR50 (G protein-coupled receptor 50), encoding both synthesis enzymes and the three main receptors of melatonin, in 109 patients with autism spectrum disorders (ASD). A cohort of 188 subjects from the general population was used as a comparison group and was genotyped for the variants identified in the patient sample. Results Several rare variants were identified in patients with ASD, including the previously reported splice site mutation in ASMT (IVS5+2T>C). Of the variants affecting protein sequence, only the V124I in the MTNR1B gene was absent in our comparison group. However, mutations were found in upstream regulatory regions in three of the genes investigated, ASMT, MTNR1A, and MTNR1B. Conclusions Our report of another ASD patient carrying the splice site mutation IVS5+2T>C, in ASMT further supports an involvement of this gene in autism. Moreover, our results also suggest that other melatonin related genes might be interesting candidates for further investigation in the search for genes involved in autism spectrum disorders and related neurobehavioral phenotypes. However, further studies of the novel variants identified in this study are warranted to shed light on their potential role in the pathophysiology of these disorders. PMID:20377855

Green synthesis of Silver and Gold Nanoparticles for Enhanced catalytic and bactericidal activity

NASA Astrophysics Data System (ADS)

Naraginti, S.; Tiwari, N.; Sivakumar, A.

2017-11-01

A rapid one step green synthetic method using kiwi fruit extract was employed for preparation of silver and gold nanoparticles. The synthesized nanoparticles were successfully used as green catalysts for the reduction of 4-nitrophenol (4-NP) and methylene blue (MB). They also exhibited excellent antimicrobial activity against clinically isolated Pseudomonas aeruginosa (P.aeruginosa) and Staphylococcus aureus (S.aureus). It was noticed that with increase in concentration of the aqueous silver and gold solutions, particle size of the Ag and Au NPS showed increase as evidenced from UV-Visible spectroscopy and TEM micrograph. The method employed for the synthesis required only a few minutes for more than 90% formation of nanoparticles when the temperature was raised to 80°C. It was also noticed that the catalytic activity of nanoparticles depends upon the size of the particles. These nanoparticles were observed to be crystalline from the clear lattice fringes in the transmission electron microscopic (TEM) images, bright circular spots in the selected area electron diffraction (SAED) pattern and peaks in the X-ray diffraction (XRD) pattern. The Fourier-transform infrared (FTIR) spectrum indicated the presence of different functional groups in the biomolecule capping the nanoparticles.

Synthesis and magnetic property of T4 virus-supported gold-coated iron ternary nanocomposite

NASA Astrophysics Data System (ADS)

Xu, Ziming; Sun, Hongjing; Gao, Faming; Hou, Li; Li, Na

2012-12-01

Herein, we present a novel method based on the use of the symmetrical T4 bacteriophage capsid as a scaffold for preparing the gold-coated iron ternary core/shell nanostructure. Results showed that the thick gold shell was obtained to effectively protect Fe core from oxidation. Magnetic measurements showed that the nanocomposites were superparamagnetic at room temperature with a blocking temperature of about 35 K. At 3 K, its coercivity of 1142.86 Oe was larger than the existing experimental values. The magnetic property of Au/T4 was also tested, demonstrating the source of the magnetic sample arising from the Fe core only. The absorption spectrum of the Fe@Au/T4 complex was measured and compared with gold/virus. Different thickness gold shells were controlled in the synthesis by tuning the Au salt addition. On the basis of results and discussion, we further speculated the general growing mechanism of the template-supported Fe@Au process.

Design and realization of the baseband processor in satellite navigation and positioning receiver

NASA Astrophysics Data System (ADS)

Zhang, Dawei; Hu, Xiulin; Li, Chen

2007-11-01

The content of this paper is focused on the Design and realization of the baseband processor in satellite navigation and positioning receiver. Baseband processor is the most important part of the satellite positioning receiver. The design covers baseband processor's main functions include multi-channel digital signal DDC, acquisition, code tracking, carrier tracking, demodulation, etc. The realization is based on an Altera's FPGA device, that makes the system can be improved and upgraded without modifying the hardware. It embodies the theory of software defined radio (SDR), and puts the theory of the spread spectrum into practice. This paper puts emphasis on the realization of baseband processor in FPGA. In the order of choosing chips, design entry, debugging and synthesis, the flow is presented detailedly. Additionally the paper detailed realization of Digital PLL in order to explain a method of reducing the consumption of FPGA. Finally, the paper presents the result of Synthesis. This design has been used in BD-1, BD-2 and GPS.

Synthesis and characterization of activated carbon from white lotus via single step chemical activation

NASA Astrophysics Data System (ADS)

Andas, Jeyashelly; Midon, Muhammad Dzulfiqar

2017-08-01

Highly porous activated carbon was successfully fabricated from the stalk of Nymphaea odorata via single step chemical activation. ZnCl2 was used as the chemical activating agent in the activation process. The raw material was preliminary characterized using Fourier Transform Infrared (FTIR), ultimate analysis (CHNS/O Analyzer) and Scanning Electron Microscope (SEM). The percentage yield, iodine number (IN) and the textural properties of the activated carbon were optimized under the influence of several synthesizing parameters such as impregnation ratio, activation temperature and activation time using ZnCl2. High IN (750.11 mg/g - 967.16 mg/g) was obtained from Sodium thiosulphate volumetric method and represents the porosity of the synthesized materials. Reduction in several functional groups was observed in the FTIR spectrum of the synthesized activated carbon. SEM analysis of the activated carbon verified the formation of highly porous surface compared to the raw Nymphaea odorata. This study provides a facile synthesis of activated carbon from waste natural resources at benign condition.

Ultrasonic-assisted chemical reduction synthesis and structural characterization of copper nanoparticles

NASA Astrophysics Data System (ADS)

Anh-Nga, Nguyen T.; Tuan-Anh, Nguyen; Thanh-Quoc, Nguyen; Ha, Do Tuong

2018-04-01

Copper nanoparticles, due to their special properties, small dimensions and low-cost preparation, have many potential applications such as in optical, electronics, catalysis, sensors, antibacterial agents. In this study, copper nanoparticles were synthesized by chemical reduction method with different conditions in order to investigate the optimum conditions which gave the smallest (particle diameter) dimensions. The synthesis step used copper (II) acetate salt as precursor, ascorbic acid as reducing agent, glycerin and polyvinylpyrrolidone (PVP) as protector and stabilizer. The assistance of ultrasonic was were considered as the significant factor affecting the size of the synthesized particles. The results showed that the copper nanoparticles have been successfully synthesized with the diameter as small as 20-40 nm and the conditions of ultrasonic waves were 48 kHz of frequency, 20 minutes of treated time and 65-70 °C of temperature. The synthesized copper nanoparticles were characterized by optical absorption spectrum, scanning electron microscopy (SEM), and Fourier Transform Infrared Spectrometry.

NESSY: NLTE spectral synthesis code for solar and stellar atmospheres

NASA Astrophysics Data System (ADS)

Tagirov, R. V.; Shapiro, A. I.; Schmutz, W.

2017-07-01

Context. Physics-based models of solar and stellar magnetically-driven variability are based on the calculation of synthetic spectra for various surface magnetic features as well as quiet regions, which are a function of their position on the solar or stellar disc. Such calculations are performed with radiative transfer codes tailored for modeling broad spectral intervals. Aims: We aim to present the NLTE Spectral SYnthesis code (NESSY), which can be used for modeling of the entire (UV-visible-IR and radio) spectra of solar and stellar magnetic features and quiet regions. Methods: NESSY is a further development of the COde for Solar Irradiance (COSI), in which we have implemented an accelerated Λ-iteration (ALI) scheme for co-moving frame (CMF) line radiation transfer based on a new estimate of the local approximate Λ-operator. Results: We show that the new version of the code performs substantially faster than the previous one and yields a reliable calculation of the entire solar spectrum. This calculation is in a good agreement with the available observations.

Optically stimulated luminescence in an imaging plate using BaFi:Eu.

PubMed

Nanto, H; Araki, T; Daimon, M; Kusano, E; Kinbara, A; Kawabata, K; Nakano, Y

2002-01-01

BaFI:Eu phosphors are fabricated using a new method of synthesis: liquid phase synthesis, in which the phosphor particles are formed through the association of Ba2+ ions, F-ions and Eu2+ ions in solution. An intense optically stimulated luminescence (OSL) peak at about 410 nm is observed by stimulating X ray irradiated BaFI:Eu phosphor with about 550-750 nm light. It is found that the peak wavelength of the optically stimulation spectrum is about 690 nm. This result suggests that the semiconductor laser can be used as the stimulating light source. It is also found that the OSL intensity is increased with increasing the X ray dose. The BaFI:Eu phosphor as a photostimulable material for the imaging plate of a computed radiography system provides the following advantages; (1) high X ray absorption coefficient, (2) high monodispersion in size which would contribute to sharp images, (3) high OSL and thus low luminescence mottle and (4) high DQE (detective quantum efficiency).

Investigating the Metastability of Clathrate Hydrates for Energy Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koh, Carolyn Ann

2014-11-18

Important breakthrough discoveries have been achieved from the DOE award on the key processes controlling the synthesis and structure-property relations of clathrate hydrates, which are critical to the development of clathrate hydrates as energy storage materials. Key achievements include: (i) the discovery of key clathrate hydrate building blocks (stable and metastable) leading to clathrate hydrate nucleation and growth; (ii) development of a rapid clathrate hydrate synthesis route via a seeding mechanism; (iii) synthesis-structure relations of H2 + CH4/CO2 binary hydrates to control thermodynamic requirements for energy storage and sequestration applications; (iv) discovery of a new metastable phase present during clathratemore » hydrate structural transitions. The success of our research to-date is demonstrated by the significant papers we have published in high impact journals, including Science, Angewandte Chemie, J. Am. Chem. Soc. Intellectual Merits of Project Accomplishments: The intellectual merits of the project accomplishments are significant and transformative, in which the fundamental coupled computational and experimental program has provided new and critical understanding on the key processes controlling the nucleation, growth, and thermodynamics of clathrate hydrates containing hydrogen, methane, carbon dioxide, and other guest molecules for energy storage. Key examples of the intellectual merits of the accomplishments include: the first discovery of the nucleation pathways and dominant stable and metastable structures leading to clathrate hydrate formation; the discovery and experimental confirmation of new metastable clathrate hydrate structures; the development of new synthesis methods for controlling clathrate hydrate formation and enclathration of molecular hydrogen. Broader Impacts of Project Accomplishments: The molecular investigations performed in this project on the synthesis (nucleation & growth)-structure-stability relations of clathrate hydrate systems are pivotal in the fundamental understanding of crystalline clathrate hydrates and the discovery of new clathrate hydrate properties and novel materials for a broad spectrum of energy applications, including: energy storage (hydrogen, natural gas); carbon dioxide sequestration; controlling hydrate formation in oil/gas transportation in subsea pipelines. The Project has also enabled the training of undergraduate, graduate and postdoctoral students in computational methods, molecular spectroscopy and diffraction, and measurement methods at extreme conditions of high pressure and low temperature.« less

Synthesis of size controllable cu-phthalocyanine nanofibers by simple solvent diffusion method and their electrochemical properties.

PubMed

Gao, Junshan; Cheng, Chuanwei; Zhou, Xuechao; Li, Yingying; Xu, Xiaoqi; Du, Xiguang; Zhang, Haiqian

2010-02-15

Tetra (2-isopropyl-5-methylphenoxy) substituted Cu-phthalocyanine nanofibers were obtained in large scale by a simple solvent diffusion method. The sizes of the fibers can be finely tuned under different solvent temperature. FE-SEM micrographs indicate that the length of the fibers changed from several hundreds micrometers to several hundreds nanometers and the width changed from several micrometers to several decade nanometers. XRD measurement showed a highly long-range ordered lamellar arrangement of the substituted Cu-phthalocyanine molecules in the microfiber and the UV-vis absorption spectrum of the fibers indicated an H-aggregate of the phthalocyanine molecules. The CV curves elucidate the CuPc fibers can be fabricated Faraday pseudocapacitor. Crown Copyright 2009. Published by Elsevier Inc. All rights reserved.

Evaluation of anti-Zika virus activities of broad-spectrum antivirals and NIH clinical collection compounds using a cell-based, high-throughput screen assay.

PubMed

Adcock, Robert S; Chu, Yong-Kyu; Golden, Jennifer E; Chung, Dong-Hoon

2017-02-01

Recent studies have clearly underscored the association between Zika virus (ZIKV) and severe neurological diseases such as microcephaly and Guillain-Barre syndrome. Given the historical complacency surrounding this virus, however, no significant antiviral screenings have been performed to specifically target ZIKV. As a result, there is an urgent need for a validated screening method and strategy that is focused on highlighting potential anti-ZIKV inhibitors that can be further advanced via rigorous validation and optimization. To address this critical gap, we sought to test whether a cell-based assay that measures protection from the ZIKV-induced cytopathic effect could serve as a high-throughput screen assay for discovering novel anti-ZIKV inhibitors. Employing this approach, we tested the anti-ZIKV activity of previously known broad-spectrum antiviral compounds and discovered several compounds (e.g., NITD008, SaliPhe, and CID 91632869) with anti-ZIKV activity. Interestingly, while GTP synthesis inhibitors (e.g., ribavirin or mycophenolic acid) were too toxic or showed no anti-ZIKV activity (EC 50  > 50 μM), ZIKV was highly susceptible to pyrimidine synthesis inhibitors (e.g., brequinar) in the assay. We amended the assay into a high-throughput screen (HTS)-compatible 384-well format and then screened the NIH Clinical Compound Collection library, which includes a total of 727 compounds organized, using an 8-point dose response format with two Zika virus strains (MR766 and PRVABC59, a recent human isolate). The screen discovered 6-azauridine and finasteride as potential anti-ZIKV inhibitors with EC 50 levels of 3.18 and 9.85 μM for MR766, respectively. We further characterized the anti-ZIKV activity of 6-azauridine and several pyrimidine synthesis inhibitors such as brequinar in various secondary assays including an antiviral spectrum test within flaviviruses and alphaviruses, Western blot (protein), real-time PCR (RNA), and plaque reduction assays (progeny virus). From these assays, we discovered that brequinar has potent anti-ZIKV activity. Our results show that a broad anti-ZIKV screen of compound libraries with our CPE-based HTS assay will reveal multiple chemotypes that could be pursued as lead compounds for therapies to treat ZIKV-associated diseases or as molecular probes to study the biology of the ZIKV replication mechanism. Copyright © 2016 Elsevier B.V. All rights reserved.

Inorganic Halogen Oxidizer Research.

DTIC Science & Technology

1977-02-04

the Synthesis and Characterization of NF BrF6 and Some Properties of NF SbF . . .. . .. . . .. . .. . .. . . . . . . A-1 Appendix B *Synthesis and...under progress. The results will be given in next year’s report in manuscript form. Attempts to record the Raman spectrum of CsBrF40 in HF solution...novel cations can be prepared according to: OSbF; + F6 25C p MF+ SbF + 02 R-77-112 14 However, no interaction was observed in either case. MICROWAVE

Diastereoselective Synthesis of a Strawberry Flavoring Agent by Epoxidation of Ethyl trans-b-Methylcinnamate

NASA Astrophysics Data System (ADS)

Pageau, Gayle J.; Mabaera, Rodwell; Kosuda, Kathryn M.; Sebelius, Tamara A.; Ghaffari, Ali H.; Kearns, Kenneth A.; McIntyre, Jean P.; Beachy, Tina M.; Thamattoor, Dasan M.

2002-01-01

The diastereoselective synthesis of ethyl (E)-3-methyl-3-phenylglycidate, a strawberry flavoring agent, is carried out by epoxidizing ethyl trans-b-methylcinnamate with m-chloroperbenzoic acid. This epoxidation is appropriate for the introductory organic laboratory and augments the small number of such experiments currently available for undergraduate education. In the course of performing this exercise, students are exposed to many important facets of organic chemistry such as synthesis, reaction mechanism, stereochemistry, chromatography, quantitative analysis, spectroscopy, and computational chemistry. The 1H NMR spectrum of this compound is especially interesting and presents instructive examples of diastereotopic protons and shielding effects of the aromatic ring current.

Platinum CCC-NHC benzimidazolyl pincer complexes: synthesis, characterization, photostability, and theoretical investigation of a blue-green emitter.

PubMed

Huckaba, Aron J; Cao, Bei; Hollis, T Keith; Valle, Henry U; Kelly, John T; Hammer, Nathan I; Oliver, Allen G; Webster, Charles Edwin

2013-06-28

The recently reported metallation/transmetallation route for the synthesis of CCC-bis(NHC) pincer ligand architectures was extended to 1,3-bis(3'-(trimethylsilylmethyl)-benzimidizol-1'-yl)benzene. The precursor was metallated with Zr(NMe2)4 and transmetallated to Pt using [Pt(COD)Cl2]. This Pt complex was found to resist photobleaching under UV irradiation in ambient conditions. Density functional theory (DFT) computations were used to generate the emission spectrum of the complex and reveal that this spectrum is the result of a transition from the triplet excited state (T1) to the ground state (S0). The Pt complex's molecular structure was determined by X-ray crystallography. The UV-vis absorption and emission spectra in solution and the solid-state emission spectra are reported. The solid-state photostability data and the radiative lifetime is also reported.

The stellar wind of an O8.5 I(f) star in M 31

NASA Technical Reports Server (NTRS)

Haser, S. M.; Lennon, D. J.; Kudritzki, R.-P.; Puls, J.; Pauldrach, A. W. A.; Bianchi, L.; Hutchings, J. B.

1995-01-01

We rediscuss the UV spectrum of OB 78#231, an O8.5 I(f) star in the Andromeda galaxy M 31, which has been obtained with the Faint Object Spectrograph on the Hubble Space Telescope by Hutchings et al. (1992). The spectrum has been re-extracted with better knowledge of background, calibration, and scattered light. The empirical analysis of the stellar wind lines results in a terminal velocity and mass loss rate similar to those typically found in comparable galactic objects. Furthermore, a comparison with an FOS spectrum of an O7 supergiant in the Small Magellanic Cloud and IUE spectra of galactic objects implies a metallicity close to galactic counterparts. These results are confirmed quantitatively by spectrum synthesis calculations using a theoretical description of O-star winds.

Disruption of melatonin synthesis is associated with impaired 14-3-3 and miR-451 levels in patients with autism spectrum disorders.

PubMed

Pagan, Cécile; Goubran-Botros, Hany; Delorme, Richard; Benabou, Marion; Lemière, Nathalie; Murray, Kerren; Amsellem, Frédérique; Callebert, Jacques; Chaste, Pauline; Jamain, Stéphane; Fauchereau, Fabien; Huguet, Guillaume; Maronde, Erik; Leboyer, Marion; Launay, Jean-Marie; Bourgeron, Thomas

2017-05-18

Autism spectrum disorders (ASD) are characterized by a wide genetic and clinical heterogeneity. However, some biochemical impairments, including decreased melatonin (crucial for circadian regulation) and elevated platelet N-acetylserotonin (the precursor of melatonin) have been reported as very frequent features in individuals with ASD. To address the mechanisms of these dysfunctions, we investigated melatonin synthesis in post-mortem pineal glands - the main source of melatonin (9 patients and 22 controls) - and gut samples - the main source of serotonin (11 patients and 13 controls), and in blood platelets from 239 individuals with ASD, their first-degree relatives and 278 controls. Our results elucidate the enzymatic mechanism for melatonin deficit in ASD, involving a reduction of both enzyme activities contributing to melatonin synthesis (AANAT and ASMT), observed in the pineal gland as well as in gut and platelets of patients. Further investigations suggest new, post-translational (reduced levels of 14-3-3 proteins which regulate AANAT and ASMT activities) and post-transcriptional (increased levels of miR-451, targeting 14-3-3ζ) mechanisms to these impairments. This study thus gives insights into the pathophysiological pathways involved in ASD.

In vivo antimicrobial activity of silver nanoparticles produced via a green chemistry synthesis using Acacia rigidula as a reducing and capping agent.

PubMed

Escárcega-González, Carlos Enrique; Garza-Cervantes, J A; Vázquez-Rodríguez, A; Montelongo-Peralta, Liliana Zulem; Treviño-González, M T; Díaz Barriga Castro, E; Saucedo-Salazar, E M; Chávez Morales, R M; Regalado Soto, D I; Treviño González, F M; Carrazco Rosales, J L; Cruz, Rocío Villalobos; Morones-Ramírez, José Rubén

2018-01-01

One of the main issues in the medical field and clinical practice is the development of novel and effective treatments against infections caused by antibiotic-resistant bacteria. One avenue that has been approached to develop effective antimicrobials is the use of silver nanoparticles (Ag-NPs), since they have been found to exhibit an efficient and wide spectrum of antimicrobial properties. Among the main drawbacks of using Ag-NPs are their potential cytotoxicity against eukaryotic cells and the latent environmental toxicity of their synthesis methods. Therefore, diverse green synthesis methods, which involve the use of environmentally friendly plant extracts as reductive and capping agents, have become attractive to synthesize Ag-NPs that exhibit antimicrobial effects against resistant bacteria at concentrations below toxicity thresholds for eukaryotic cells. In this study, we report a green one-pot synthesis method that uses Acacia rigidula extract as a reducing and capping agent, to produce Ag-NPs with applications as therapeutic agents to treat infections in vivo. The Ag-NPs were characterized using transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction, energy-dispersive spectroscopy, ultraviolet-visible, and Fourier transform infrared. We show that Ag-NPs are spherical with a narrow size distribution. The Ag-NPs show antimicrobial activities in vitro against Gram-negative ( Escherichia coli , Pseudomonas aeruginosa , and a clinical multidrug-resistant strain of P. aeruginosa ) and Gram-positive ( Bacillus subtilis ) bacteria. Moreover, antimicrobial effects of the Ag-NPs, against a resistant P. aeruginosa clinical strain, were tested in a murine skin infection model. The results demonstrate that the Ag-NPs reported in this work are capable of eradicating pathogenic resistant bacteria in an infection in vivo. In addition, skin, liver, and kidney damage profiles were monitored in the murine infection model, and the results demonstrate that Ag-NPs can be used safely as therapeutic agents in animal models. Together, these results suggest the potential use of Ag-NPs, synthesized by green chemistry methods, as therapeutic agents against infections caused by resistant and nonresistant strains.

Discovery of BMS-955176, a Second Generation HIV-1 Maturation Inhibitor with Broad Spectrum Antiviral Activity.

PubMed

Regueiro-Ren, Alicia; Liu, Zheng; Chen, Yan; Sin, Ny; Sit, Sing-Yuen; Swidorski, Jacob J; Chen, Jie; Venables, Brian L; Zhu, Juliang; Nowicka-Sans, Beata; Protack, Tricia; Lin, Zeyu; Terry, Brian; Samanta, Himadri; Zhang, Sharon; Li, Zhufang; Beno, Brett R; Huang, Xiaohua S; Rahematpura, Sandhya; Parker, Dawn D; Haskell, Roy; Jenkins, Susan; Santone, Kenneth S; Cockett, Mark I; Krystal, Mark; Meanwell, Nicholas A; Hanumegowda, Umesh; Dicker, Ira B

2016-06-09

HIV-1 maturation inhibition (MI) has been clinically validated as an approach to the control of HIV-1 infection. However, identifying an MI with both broad polymorphic spectrum coverage and good oral exposure has been challenging. Herein, we describe the design, synthesis, and preclinical characterization of a potent, orally active, second generation HIV-1 MI, BMS-955176 (2), which is currently in Phase IIb clinical trials as part of a combination antiretroviral regimen.

Manganese toxicity to chlorophyll synthesis in tobacco callus. [Nicotiana tabacum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clairmont, K.B.; Hagar, W.G.; Davis, E.A.

1986-01-01

Tobacco (Nicotiana tabacum) pith explants were grown on manganese containing medium. At moderate concentration (10 millimolar), manganese selectivity inhibited chlorophyll synthesis, resulting initially in growth of white callus. Several weeks later the white callus turned brown due to the accumulation of a pigment identified as protoporphyrin IX by its elution profile using high performance liquid chromatography, by its absorption spectrum, and by its fluorescence properties. At a concentration of 100 millimolar manganese the pigment accumulated without growth of the explant.

Synthesis and characterization of polypyrrole grafted chitin

NASA Astrophysics Data System (ADS)

Ramaprasad, A. T.; Latha, D.; Rao, Vijayalakshmi

2017-05-01

Synthesis and characterization of chitin grafted with polypyrrole (PPy) is reported in this paper. Chitin is soaked in pyrrole solution of various concentrations for different time intervals and polymerized using ammonium peroxy disulphate (APS) as an initiator. Grafting percentage of polypyrrole onto chitin is calculated from weight of chitin before and after grafting. Grafting of polymer is further verified by dissolution studies. The grafted polymer samples are characterized by FTIR, UV-Vis absorption spectrum, XRD, DSC, TGA, AFM, SEM and conductivity studies.

Synthesis and characterization of zeolite from coal fly ash

NASA Astrophysics Data System (ADS)

Liu, Yong; Luo, Qiong; Wang, Guodong; Li, Xianlong; Na, Ping

2018-05-01

Fly ash (FA) from coal-based thermal power plant was used to synthesize zeolite in NaOH solution with hydrothermal method in this work. Firstly, the effects of calcination and acid treatment on the removal of impurities in fly ash were studied. Then based on the pretreated FA, the effects of alkali concentration, reaction temperature and Si/Al ratio on the synthesis of zeolite were studied in detail. The mineralogy, morphology, thermal behavior, infrared spectrum and specific surface for the synthetic sample were investigated. The results indicated that calcination at 750 °C for 1.5 h can basically remove unburned carbon from FA, and 4 M hydrochloric acid treatment of calcined FA at 90 °C for 2 h will reduce the quality of about 34.3%wt, which are mainly iron, calcium and sulfur elements. The concentration of NaOH, reaction temperature and Si/Al ratio have important effect on the synthesis of zeolite. In this study, 0.5 M NaOH cannot obtain any zeolite. High temperature is beneficial to zeolite synthesis from FA, but easily lead to a variety of zeolites. The synthetic sample contains three kinds of zeolites such as zeolite P, sodalite and zeolite X, when the reaction conditions are 2 M NaOH and 120 °C for 24 h. In this research, quartz always exists in the synthetic sample, but will reduce with the increase of temperature. The synthetic zeolite has the specific surface area of about 42 m2 g‑1 and better thermal stability.

Facile combustion synthesis of ZnO nanoparticles using Cajanus cajan (L.) and its multidisciplinary applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manjunath, K.; Ravishankar, T.N.; Kumar, Dhanith

Graphical abstract: Facile combustion synthesis of ZnO nanoparticles using Cajanuscajan (L.) and its multidisciplinary applications.Zinc oxide nanoparticles were successfully synthesized by solution combustion method (SCM) using pigeon pea as a combustible fuel for the first time. The as-prepared product shows good photocatalytic, dielectric, antibacterial, electrochemical properties. - Highlights: • ZnO Nps were synthesized via combustion method using pigeon pea as a fuel. • The structure of the product was confirmed by XRD technique. • The morphology was confirmed by SEM and TEM images. • The as-prepared product shown good photocatalytic activity, dielectric property. • It has also shown good antibacterialmore » and electrochemical properties. - Abstract: Zinc oxide nanoparticles (ZnO Nps) were successfully synthesized by solution combustion method (SCM) using pigeon pea as a fuel for the first time. X-Ray diffraction pattern reveals that the product belongs to hexagonal system. FTIR spectrum of ZnO Nps shows the band at 420 cm{sup −1} associated with the characteristic vibration of Zn–O. TEM images show that the nanoparticles are found to be ∼40–80 nm. Furthermore, the as-prepared ZnO Nps exhibits good photocatalytic activity for the photodegradation of methylene blue (MB), indicating that they are indeed a promising photocatalytic semiconductor. The antibacterial properties of ZnO nanopowders were investigated by their bactericidal activity against four bacterial strains.« less

Surface morphology and molecular bonding of CaCO3 nanocrystallites by gas diffusion method

NASA Astrophysics Data System (ADS)

Sulimai, N. H.; Rani, Rozina Abdul; Khusaimi, Z.; Abdullah, S.; Salifairus, M. J.; Alrokayan, Salman; Khan, Haseeb; Rusop, M.

2018-05-01

Calcium carbonate with the chemical formula of (CaCO3) is the most abundant element in the world. Its usage on certain applications is largely affected by its properties. The best means to control its properties is through controlled preparation of CaCO3. This study uses diffusion method between the precursors Calcium Chloride and Ammonium Carbonate. Instead of using water, ethanol was used to prepare the salt. Reaction was done in room temperature (RT) for 6h-24h. Smallest average crystallite size measured by FESEM micrograph is 500nm produced by synthesis of CaCO3 reacted for 168 hours. From energy-dispersive X-ray spectrum also indicated the smallest particle size is by CaCO3 reacted for 168 hours. Changes was seen for element Ca at 3.7keV.

Chemical synthesis of hexagonal indium nitride nanocrystallines at low temperature

NASA Astrophysics Data System (ADS)

Wang, Liangbiao; Shen, Qianli; Zhao, Dejian; Lu, Juanjuan; Liu, Weiqiao; Zhang, Junhao; Bao, Keyan; Zhou, Quanfa

2017-08-01

In this study, hexagonal indium nitride nanocystallines with high crystallinity have been prepared by the reaction of InCl3·4H2O, sulfur and NaNH2 in an autoclave at 160 °C. The crystal structures and morphologies of the obtained InN sample are characterized by X-ray diffraction and scanning electron microscope. As InCl3·4H2O is substituted by In(NO3)3·4.5H2O, InN nanocrystallines could also be obtained by using the similar method. The photoluminescence spectrum shows that the InN emits a broad peak positioned at 2.3 eV.

Structural phase analysis and photoluminescence properties of Mg-doped TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Ali, T.; Ashraf, M. Anas; Ali, S. Asad; Ahmed, Ateeq; Tripathi, P.

2018-05-01

In this paper, we report the synthesis, characterization and photoluminescence properties of Mg-doped TiO2 nanoparticles (NPs). The samples were synthesized by sol-gel method and characterized using the standard analytical techniques such as X-ray diffraction (XRD), Transmission electron microscope (TEM), Energy dispersive X-ray spectroscopy (EDX), UV-visible and photoluminescence spectroscopy. The powder XRD spectra revealed that the synthesized samples are pure and crystalline in nature and showing tetragonal anatase phase of TiO2 NPs. UV-visible spectrum illustrates that an absorption edge shifts toward the visible region. This study may provide a new insight for making the nanomaterials which can be used in photocatalytic applications.

Optical and Luminescence Properties of β-NaFeO2 Nanoparticles

NASA Astrophysics Data System (ADS)

Singh, Sarbjit; Tangra, Ankush Kumar; Lotey, Gurmeet Singh

2018-05-01

β-NaFeO2 nanoparticles have been synthesized by sol-gel method and their morphological, structural and optical properties investigated. Transmission electron microscope study reveals that the size of the synthesis nanoparticles is 37 nm and they are possessing spherical symmetry. X-ray diffraction pattern shows the orthorhombic crystal structure of nanoparticles with space group Pn21 a. UV-visible spectra of β-NaFeO2 divulges that these nanoparticles have direct band gap 2.35 eV. The observed Fourier transform infrared spectroscopy spectra confirms the presence of Fe-Na bonding at 1074 cm-1. The photoluminescence study of these nanoparticles shows that these nanoparticles possesses various transition in the visible spectrum.

Ultrasound and photochemical procedures for nanocatalysts preparation: application in photocatalytic biomass valorization.

PubMed

Colmenares, Juan Carlos

2013-07-01

Nano-photocatalysis is becoming increasingly important due to its multiple applications and multidisciplinary aspects. Applications such as water/air purification, solar energy storage, chemicals production and optoelectronics are some of the most promising. In recent years, the development of novel environmental friendly and cost efficient methods for materials preparation that could replace the old ones is on demand. Unconventional and "soft" techniques such as sonication and photochemistry offer huge possibilities for the synthesis of a broad spectrum of nanostructured materials (e.g., nano-photocatalysts). In the present study, I focus on ultrasound and photochemical procedures for the preparation of nanostructured photocatalysts (e.g., supported metals, metal oxides) and their application in food organic wastes valorization.

Hydrocarbon and nonhydrocarbon derivatives of cyclopropane

NASA Technical Reports Server (NTRS)

Slabey, Vernon A; Wise, Paul H; Gibbons, Louis C

1953-01-01

The methods used to prepare and purify 19 hydrocarbon derivatives of cyclopropane are discussed. Of these hydrocarbons, 13 were synthesized for the first time. In addition to the hydrocarbons, six cyclopropylcarbinols, five alkyl cyclopropyl ketones, three cyclopropyl chlorides, and one cyclopropanedicarboxylate were prepared as synthesis intermediates. The melting points, boiling points, refractive indices, densities, and, in some instances, heats of combustion of both the hydrocarbon and nonhydrocarbon derivatives of cyclopropane were determined. These data and the infrared spectrum of each of the 34 cyclopropane compounds are presented in this report. The infrared absorption bands characteristic of the cyclopropyl ring are discussed, and some observations are made on the contribution of the cyclopropyl ring to the molecular refractions of cyclopropane compounds.

ZnO nanowires: Synthesis and charge transfer mechanism in the detection of ammonia vapour

NASA Astrophysics Data System (ADS)

Nancy Anna Anasthasiya, A.; Ramya, S.; Rai, P. K.; Jeyaprakash, B. G.

2018-01-01

ZnO nanowires with hexagonal wurtzite structure were grown on the glass substrate using Successive Ionic Layer Adsorption and Reaction (SILAR) method. Both experimental and theoretical studies demonstrated that NH3 chemisorbed and transferred the charge to the surface of the nanowire via its nitrogen site to the zinc site of ZnO nanowires, leading to the detection of NH3 vapour. The adsorbed ammonia dissociated into NH2 and H due to steric repulsion, and then into N2 and H2 gas. The formation of the N2 gas during the desorption process confirmed by observing peak at 14 and 28 m/z in the GC-MS spectrum.

Synthesis of ultrawideband radiation of combined antenna arrays excited by nanosecond bipolar voltage pulses

NASA Astrophysics Data System (ADS)

Koshelev, V. I.; Plisko, V. V.; Sevostyanov, E. A.

2017-05-01

To broaden the spectrum of high-power ultrawideband radiation, it is suggested to synthesize an electromagnetic pulse summing the pulses of different length in free space. On the example of model pulses corresponding to radiation of combined antennas excited by bipolar voltage pulses of the length of 2 and 3 ns, the possibility of twofold broadening of the radiation spectrum was demonstrated. Radiation pulses with the spectrum width exceeding three octaves were obtained. Pattern formation by the arrays of different geometry excited by the pulses having different time shifts was considered. Optimum array structure with the pattern maximum in the main direction was demonstrated on the example of a 2×2 array.

Luminescence properties of Na2Sr2Al2PO4Cl9:Sm3+ phosphor

NASA Astrophysics Data System (ADS)

Tamboli, Sumedha; Shahare, D. I.; Dhoble, S. J.

2018-04-01

A series of Sm3+ ions doped Na2Sr2Al2PO4Cl9 phosphors were synthesized via solid state synthesis method. Photoluminescence (PL) emission spectra were obtained by keeping excitation wavelength at 406 nm. Emission spectra show three emission peaks at 563 nm, 595 nm and 644 nm. The CIE chromaticity diagram shows emission colour of the phosphor in the orange-red region of the visible spectrum, indicating that the phosphor may be useful in preparing orange light-emitting diodes. Na2Sr2Al2PO4Cl9:Sm3+ phosphors were irradiated by γ-rays from a 60Co source and β-rays from a 90Sr source. Their thermoluminescence (TL) glow curves were obtained by Nucleonix 1009I TL reader. TL Trapping parameters such as activation energy of trapped electrons and order of kinetics were obtained by using Chen's peak shape method, Glow curve fitting method and initial rise method.

Are Fluoroquinolones Appropriate for the Treatment of Extended-Spectrum β-Lactamase-Producing Gram-Negative Bacilli?

PubMed Central

Wiener, Emily S.; Heil, Emily L.; Hynicka, Lauren M.; Johnson, J. Kristie

2015-01-01

Objective: To review the data analyzing the role of fluoroquinolones in the treatment of extended-spectrum β-lactamase (ESBL)-producing infections and rates and methods of co-transmission of resistance. Data Sources: A MEDLINE literature search was performed using the search terms extended-spectrum beta-lactamase, fluoroquinolone, ciprofloxacin, levofloxacin, plasmid transmission, and resistance from 1996 to June 2015. Additional references were identified from a review of literature citations. Study Selection and Data Extraction: All English-language retrospective studies, prospective studies, and meta-analyses assessing efficacy of fluoroquinolone use in ESBL infections, assessing methods of resistance transmission, or analyzing patient risk factors were reviewed. Data Synthesis: A total of 18 studies that analyzed fluoroquinolone resistance and association to ESBL producing bacteria from either molecular or clinical perspectives were idenitifed. Four studies evaluated the genetic association between ESBL transmission and fluoroquinolone resistance. Plasmid mediated quinolone resistance was found in higher rates in ESBL-producing bacteria. Numerous studies analyzed the risk factors of co-occurring resistance identifying nosocomial acquired infections, recent hospitalization, long-term care facility residence, and intensive care unit stay as the most common. Conclusive clinical data are lacking; however, a meta-analysis showed fluoroquinolones had higher odds of all-cause mortality when used empirically to treat ESBL bacteremia compared with carbapenems. Conclusions: Fluoroquinolone resistance may be co-transmitted in ESBL-producing Enterobacteriaceae. There are limited data on the efficacy for fluoroquinolones in the treatment of ESBL-producing infections. Additional prospective trials are needed to definitively determine the role of fluoroquinolones in ESBL infections.

Interactive spectral analyzer and comparator (ISAAC)

NASA Astrophysics Data System (ADS)

Latković, O.; Cséki, A.; Vince, I.

2003-10-01

We are developing an application for graphical comparison of observed and synthetic spectra (ISAAC). Synthetic spectrum calculation is performed by SPECTRUM, Stellar Spectral Synthesis Program by Richard O. Gray that we use with his kind permission. This program computes line profiles under LTE conditions in the given wavelength interval using a stellar (solar) atmosphere model, a spectral line data list (wavelength, energy levels, oscillator strengths, and damping constants), a file containing data for atoms and molecules, as well as a data file for hydrogen line profiles calculation. ISAAC offers a simple interface for viewing and changing any atomic parameter SPECTRUM uses for line profile calculation, enabling quick comparison of the new synthetic line profile with the observed one. In this way parameters like relative abundances, oscillator strengths and van der Waals damping constants can be improved, achieving a better agreement with the observed spectrum.

Synthesis and antifungal activities of miltefosine analogs

USDA-ARS?s Scientific Manuscript database

Nine alkylphosphocholine derivatives (3a-3i) were prepared by modifying the choline structural moiety and the alkyl chain length of miltefosine (hexadecylphosphocholine), a broad-spectrum antifungal compound that has shown modest therapeutic efficacy in a mouse model of cryptococcosis. The synthetic...

Flow “Fine” Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods

PubMed Central

2015-01-01

Abstract The concept of flow “fine” synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow “fine” synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. PMID:26337828

Synthesis and characterization of Gd-doped magnetite nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Honghu; Iowa State Univ., Ames, IA; Malik, Vikash

There has been rising interest in the synthesis of magnetite nanoparticles due to their importance in biomedical and technological applications. Tunable magnetic properties of magnetite nanoparticles to meet specific requirements will greatly expand the spectrum of applications. Tremendous efforts have been devoted to studying and controlling the size, shape and magnetic properties of magnetite nanoparticles. We investigate gadolinium (Gd) doping to influence the growth process as well as magnetic properties of magnetite nanocrystals via a simple co-precipitation method under mild conditions in aqueous media. Gd doping was found to affect the growth process leading to synthesis of controllable particle sizesmore » under the conditions tested (0–10 at% Gd 3+). Typically, undoped and 5 at% Gd-doped magnetite nanoparticles were found to have crystal sizes of about 18 and 44 nm, respectively, supported by X-ray diffraction and transmission electron microscopy. These results showed that Gd-doped nanoparticles retained the magnetite crystal structure, with Gd 3+ randomly incorporated in the crystal lattice, probably in the octahedral sites. The composition of 5 at% Gd-doped magnetite was Fe (3-x)Gd xO 4 (x=0.085±0.002), as determined by inductively coupled plasma mass spectrometry. 5 at% Gd-doped nanoparticles exhibited ferrimagnetic properties with small coercivity (~65 Oe) and slightly decreased magnetization at 260 K in contrast to the undoped, superparamagnetic magnetite nanoparticles. Templation by the bacterial biomineralization protein Mms6 did not appear to affect the growth of the Gd-doped magnetite particles synthesized by this method.« less

Synthesis and characterization of Gd-doped magnetite nanoparticles

DOE PAGES

Zhang, Honghu; Iowa State Univ., Ames, IA; Malik, Vikash; ...

2016-10-04

There has been rising interest in the synthesis of magnetite nanoparticles due to their importance in biomedical and technological applications. Tunable magnetic properties of magnetite nanoparticles to meet specific requirements will greatly expand the spectrum of applications. Tremendous efforts have been devoted to studying and controlling the size, shape and magnetic properties of magnetite nanoparticles. We investigate gadolinium (Gd) doping to influence the growth process as well as magnetic properties of magnetite nanocrystals via a simple co-precipitation method under mild conditions in aqueous media. Gd doping was found to affect the growth process leading to synthesis of controllable particle sizesmore » under the conditions tested (0–10 at% Gd 3+). Typically, undoped and 5 at% Gd-doped magnetite nanoparticles were found to have crystal sizes of about 18 and 44 nm, respectively, supported by X-ray diffraction and transmission electron microscopy. These results showed that Gd-doped nanoparticles retained the magnetite crystal structure, with Gd 3+ randomly incorporated in the crystal lattice, probably in the octahedral sites. The composition of 5 at% Gd-doped magnetite was Fe (3-x)Gd xO 4 (x=0.085±0.002), as determined by inductively coupled plasma mass spectrometry. 5 at% Gd-doped nanoparticles exhibited ferrimagnetic properties with small coercivity (~65 Oe) and slightly decreased magnetization at 260 K in contrast to the undoped, superparamagnetic magnetite nanoparticles. Templation by the bacterial biomineralization protein Mms6 did not appear to affect the growth of the Gd-doped magnetite particles synthesized by this method.« less

Gemcitabine and Nucleos(t)ide Synthesis Inhibitors Are Broad-Spectrum Antiviral Drugs that Activate Innate Immunity.

PubMed

Shin, Hye Jin; Kim, Chonsaeng; Cho, Sungchan

2018-04-20

Nucleoside analogs have been frequently identified as antiviral agents. In recent years, gemcitabine, a cytidine analog in clinical use for the treatment of many solid tumors, was also shown to have antiviral activity against a broad range of viruses. Nucleoside analogs generally interfere with cellular nucleos(t)ide synthesis pathways, resulting in the depletion or imbalance of (d)NTP pools. Intriguingly, a few recent reports have shown that some nucleoside analogs, including gemcitabine, activated innate immunity, inducing the expression of interferon-stimulated genes, through nucleos(t)ide synthesis inhibition. The precise crosstalk between these two independent processes remains to be determined. Nonetheless, we summarize the current knowledge of nucleos(t)ide synthesis inhibition-related innate immunity and propose it as a newly emerging antiviral mechanism of nucleoside analogs.

Coordination of FocA and Pyruvate Formate-Lyase Synthesis in Escherichia coli Demonstrates Preferential Translocation of Formate over Other Mixed-Acid Fermentation Products

PubMed Central

Beyer, Lydia; Doberenz, Claudia; Falke, Dörte; Hunger, Doreen; Suppmann, Bernhard

2013-01-01

Enterobacteria such as Escherichia coli generate formate, lactate, acetate, and succinate as major acidic fermentation products. Accumulation of these products in the cytoplasm would lead to uncoupling of the membrane potential, and therefore they must be either metabolized rapidly or exported from the cell. E. coli has three membrane-localized formate dehydrogenases (FDHs) that oxidize formate. Two of these have their respective active sites facing the periplasm, and the other is in the cytoplasm. The bidirectional FocA channel translocates formate across the membrane delivering substrate to these FDHs. FocA synthesis is tightly coupled to synthesis of pyruvate formate-lyase (PflB), which generates formate. In this study, we analyze the consequences on the fermentation product spectrum of altering FocA levels, uncoupling FocA from PflB synthesis or blocking formate metabolism. Changing the focA translation initiation codon from GUG to AUG resulted in a 20-fold increase in FocA during fermentation and an ∼3-fold increase in PflB. Nevertheless, the fermentation product spectrum throughout the growth phase remained similar to that of the wild type. Formate, acetate, and succinate were exported, but only formate was reimported by these cells. Lactate accumulated in the growth medium only in mutants lacking FocA, despite retaining active PflB, or when formate could not be metabolized intracellularly. Together, these results indicate that FocA has a strong preference for formate as a substrate in vivo and not other acidic fermentation products. The tight coupling between FocA and PflB synthesis ensures adequate substrate delivery to the appropriate FDH. PMID:23335413

Cellular imaging using BODIPY-, pyrene- and phthalocyanine-based conjugates.

PubMed

Bizet, Faustine; Ipuy, Martin; Bernhard, Yann; Lioret, Vivian; Winckler, Pascale; Goze, Christine; Perrier-Cornet, Jean-Marie; Decréau, Richard A

2018-01-15

Fluorescent Probes aimed at absorbing in the blue/green region of the spectrum and emitting in the green/red have been synthesized (as the form of dyads-pentads), studied by spectrofluorimetry, and used for cellular imaging. The synthesis of phthalocyanine-pyrene 1 was achieved by cyclotetramerization of pyrenyldicyanobenzene, whereas phthalocyanine-BODIPY 2c was synthesized by Sonogashira coupling between tetraiodophthalocyanine and meso-alkynylBODIPY. The standard four-steps BODIPY synthesis was applied to the BODIPY-pyrene dyad 3 starting from pyrenecarbaldehyde and dimethylpyrrole. 1 H, 13 C, 19 F, 11 BNMR, ICP, MS, and UV/Vis spectroscopic analyses demonstrated that 2c is a mixture of BODIPY-Pc conjugates corresponding to an average ratio of 2.5 BODIPY per Pc unit, where its bis, tris, tetrakis components could not be separated. Fluorescence emission studies (μM concentration in THF) showed that the design of the probes allowed excitation of their antenna (pyrene, BODIPY) in the blue/green region of the spectrum, and subsequent transfer to the acceptor platform (BODIPY, phthalocyanine) followed by its emission in the green/red (with up to 140-350 nm overall Stokes shifts). The fluorescent probes were used for cellular imaging of B16F10 melanoma cells upon solubilization in 1% DMSO containing RPMI or upon encapsulation in liposomes (injection method). Probes were used at 1-10 μM concentrations, cells were fixed with methanol and imaged by biphoton and/or confocal microscopy, showing that probes could achieve the staining of cells membranes and not the nucleus. Copyright © 2017. Published by Elsevier Ltd.

Synthesis and photosensor study of as-grown CuZnO thin film by facile chemical bath deposition

NASA Astrophysics Data System (ADS)

Gubari, Ghamdan M. M.; Ibrahim Mohammed S., M.; Huse, Nanasaheb P.; Dive, Avinash S.; Sharma, Ramphal

2018-05-01

We have successfully deposited CuZnO thin film on a glass substrate by facile chemical bath deposition method at 85 °C for 1 hr. Structural, topographical, Optical and Electrical properties of the prepared Thin Films were investigated by XRD, Raman spectrum, AFM, UV-Visible Spectrophotometer and I-V Measurement System respectively. The X-ray diffraction (XRD) pattern confirmed the formation of the CuZnO composition when compared with standard JCPDS card (JCPDF # 75-0576 & # 36-1451). The Raman analysis shows a major peak at 458 cm-1 with E2 (High) vibrational mode. AFM images revealed uniform deposition over an entire glass substrate with 66.2 nm average roughness of the film. From the optical absorption spectrum, clear band edge around ˜407 nm was observed which results in a wide energy band gap of ˜3.04 eV. The electrical properties were measured at room temperature in the voltage range ±5 V, showed a drastic enhancement in current under light illumination with the highest photosensitivity of ˜99.9 % for 260 W.

Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators

PubMed Central

Dulski, Kamil; Niedźwiecki, Szymon; Alfs, Dominika; Białas, Piotr; Curceanu, Catalina; Czerwiński, Eryk; Danel, Andrzej; Gajos, Aleksander; Głowacz, Bartosz; Gorgol, Marek; Hiesmayr, Beatrix; Jasińska, Bożena; Kacprzak, Krzysztof; Kamińska, Daria; Kapłon, Łukasz; Kochanowski, Andrzej; Korcyl, Grzegorz; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Kubicz, Ewelina; Kucharek, Mateusz; Mohammed, Muhsin; Pawlik-Niedźwiecka, Monika; Pałka, Marek; Raczyński, Lech; Rudy, Zbigniew; Rundel, Oleksandr; Sharma, Neha G.; Silarski, Michał; Uchacz, Tomasz; Wiślicki, Wojciech; Zgardzińska, Bożena; Zieliński, Marcin; Moskal, Paweł

2017-01-01

A novel plastic scintillator is developed for the application in the digital positron emission tomography (PET). The novelty of the concept lies in application of the 2-(4-styrylphenyl)benzoxazole as a wavelength shifter. The substance has not been used as scintillator dopant before. A dopant shifts the scintillation spectrum towards longer wavelengths making it more suitable for applications in scintillators of long strips geometry and light detection with digital silicon photomultipliers. These features open perspectives for the construction of the cost-effective and MRI-compatible PET scanner with the large field of view. In this article we present the synthesis method and characterize performance of the elaborated scintillator by determining its light emission spectrum, light emission efficiency, rising and decay time of the scintillation pulses and resulting timing resolution when applied in the positron emission tomography. The optimal concentration of the novel wavelength shifter was established by maximizing the light output and it was found to be 0.05 ‰ for cuboidal scintillator with dimensions of 14 mm x 14 mm x 20 mm. PMID:29176834

Fatigue Damage Spectrum calculation in a Mission Synthesis procedure for Sine-on-Random excitations

NASA Astrophysics Data System (ADS)

Angeli, Andrea; Cornelis, Bram; Troncossi, Marco

2016-09-01

In many real-life environments, certain mechanical and electronic components may be subjected to Sine-on-Random vibrations, i.e. excitations composed of random vibrations superimposed on deterministic (sinusoidal) contributions, in particular sine tones due to some rotating parts of the system (e.g. helicopters, engine-mounted components,...). These components must be designed to withstand the fatigue damage induced by the “composed” vibration environment, and qualification tests are advisable for the most critical ones. In the case of an accelerated qualification test, a proper test tailoring which starts from the real environment (measured vibration signals) and which preserves not only the accumulated fatigue damage but also the “nature” of the excitation (i.e. sinusoidal components plus random process) is important to obtain reliable results. In this paper, the classic time domain approach is taken as a reference for the comparison of different methods for the Fatigue Damage Spectrum (FDS) calculation in case of Sine-on-Random vibration environments. Then, a methodology to compute a Sine-on-Random specification based on a mission FDS is proposed.

Novel scintillating material 2-(4-styrylphenyl)benzoxazole for the fully digital and MRI compatible J-PET tomograph based on plastic scintillators.

PubMed

Wieczorek, Anna; Dulski, Kamil; Niedźwiecki, Szymon; Alfs, Dominika; Białas, Piotr; Curceanu, Catalina; Czerwiński, Eryk; Danel, Andrzej; Gajos, Aleksander; Głowacz, Bartosz; Gorgol, Marek; Hiesmayr, Beatrix; Jasińska, Bożena; Kacprzak, Krzysztof; Kamińska, Daria; Kapłon, Łukasz; Kochanowski, Andrzej; Korcyl, Grzegorz; Kowalski, Paweł; Kozik, Tomasz; Krzemień, Wojciech; Kubicz, Ewelina; Kucharek, Mateusz; Mohammed, Muhsin; Pawlik-Niedźwiecka, Monika; Pałka, Marek; Raczyński, Lech; Rudy, Zbigniew; Rundel, Oleksandr; Sharma, Neha G; Silarski, Michał; Uchacz, Tomasz; Wiślicki, Wojciech; Zgardzińska, Bożena; Zieliński, Marcin; Moskal, Paweł

2017-01-01

A novel plastic scintillator is developed for the application in the digital positron emission tomography (PET). The novelty of the concept lies in application of the 2-(4-styrylphenyl)benzoxazole as a wavelength shifter. The substance has not been used as scintillator dopant before. A dopant shifts the scintillation spectrum towards longer wavelengths making it more suitable for applications in scintillators of long strips geometry and light detection with digital silicon photomultipliers. These features open perspectives for the construction of the cost-effective and MRI-compatible PET scanner with the large field of view. In this article we present the synthesis method and characterize performance of the elaborated scintillator by determining its light emission spectrum, light emission efficiency, rising and decay time of the scintillation pulses and resulting timing resolution when applied in the positron emission tomography. The optimal concentration of the novel wavelength shifter was established by maximizing the light output and it was found to be 0.05 ‰ for cuboidal scintillator with dimensions of 14 mm x 14 mm x 20 mm.

Synthesis and physicochemical properties of bis(L-asparaginato) zinc(II): A promising new semiorganic crystal with high laser damage threshold for shorter wavelength generation

NASA Astrophysics Data System (ADS)

Subhashini, R.; Arjunan, S.

2018-05-01

An exceedingly apparent nonlinear semiorganic optical crystals of bis(L-asparaginato)zinc(II) [BLAZ], was synthesized by a traditional slow evaporation solution growth technique. The cell parameters were estimated from single crystal X-ray diffraction analysis. Spectroscopic study substantiates the presence of functional groups. The UV spectrum shows the sustenance of wide transparency window and several optical constants, such as extinction coefficient (K), refractive index, optical conductivity and electric susceptibility with real and imaginary parts of dielectric constant were calculated using the transmittance data. The fluorescence emission spectrum of the crystal pronounces red emission. The laser induced surface damage threshold of the crystal was measured using Nd:YAG laser. The output intensity of second harmonic generation was estimated using the Kurtz and Perry powder method. The hardness stability was investigated by Vickers microhardness test. The decomposition and thermal stability of the compound were scrutinized by TGA-DSC studies. Dielectric studies were carried out to anatomize the electrical properties of the crystal. SEM analysis reveals the existence of minute crystallites on the growth surface.

Microwave Assisted Synthesis of 1-[5-(Substituted Aryl)-1H-Pyrazol-3-yl]-3,5-Diphenyl-1H-1,2,4-Triazole as Antinociceptive and Antimicrobial Agents

PubMed Central

Khanage, Shantaram Gajanan; Mohite, Popat Baban; Pandhare, Ramdas Bhanudas; Raju, S. Appala

2014-01-01

Purpose: An efficient technique has been developed for microwave assisted synthesis of 1-[5-(substituted aryl)-1H-pyrazol-3-yl]-3,5-diphenyl-1H-1,2,4-triazole as antinociceptive and antimicrobial agents. Methods: The desired compounds (S1-S10) were synthesized by the microwave irradiation via cyclization of formerly synthesized chalcones of 3,5-diphenyl-1H-1,2,4-triazole and hydrazine hydrate in mild acidic condition. All newly synthesized compounds were subjected to study their antinociceptive and antimicrobial activity. The analgesic potential of compounds was tested by acetic acid induced writhing response and hot plate method. The MIC values for antimicrobial activity were premeditated by liquid broth method. Results: The compounds S1, S2, S4, S6 and S10 were found to be excellent peripherally acting analgesic agents when tested on mice by acetic acid induced writhing method and compounds S3, S6 and S1 at dose level of 100 mg/kg were exhibited superior centrally acting antinociceptive activity when tested by Eddy’s hot plate method. In antimicrobial activity compound S10 found to be broad spectrum antibacterial agent at MIC value of 15.62 µg/ml and compound S6 was exhibited antifungal potential at 15.62 µg/mL on both fungal strains. Conclusion: Some novel pyrazoles clubbed with 1,2,4-triazole derivatives were synthesized and evaluated as possible antimicrobial, centrally and peripherally acting analgesics. PMID:24511473

MICROWAVE EFFECTS IN ORGANIC SYNTHESIS: MECHANISTIC AND REACTION MEDIUM CONSIDERATIONS

EPA Science Inventory

The scope of applications of microwave irradiation relates to a wide spectrum of organic syntheses with numerous benefits (reduction in reaction times, improved purity of products and better yields) encompassing advantages of both thermal and (or) specific non-purely thermal effe...

Synthesis and characterization of spin-coated ZnS thin films

NASA Astrophysics Data System (ADS)

Zaman, M. Burhanuz; Chandel, Tarun; Dehury, Kshetramohan; Rajaram, P.

2018-05-01

In this paper, we report synthesis of ZnS thin films using a sol-gel method. A unique aprotic solvent, dimethlysulphoxide (DMSO) has been used to obtain a homogeneous ZnS gel. Zinc acetate and thiourea were used as the precursor sources for Zn and S, respectively, to deposit nanocrystalline ZnS thin films. Optical, structural and morphological properties of the films were studied. Optical studies reveal high transmittance of the samples over the entire visible region. The energy band gap (Eg) for the ZnS thin films is found to be about 3.6 eV which matches with that of bulk ZnS. The interference fringes in transmissions spectrum show the high quality of synthesized samples. Strong photoluminescence peak in the UV region makes the films suitable for optoelectronic applications. X-ray diffraction studies reveal that sol-gel derived ZnS thin films are polycrystalline in nature with hexagonal structure. SEM studies confirmed that the ZnS films show smooth and uniform grains morphology having size in 20-25 nm range. The EDAX studies confirmed that the films are nearly stoichiometric.

Synthesis and characterization of silver nanoparticles from Alpinia calcarata by Green approach and its applications in bactericidal and nonlinear optics

NASA Astrophysics Data System (ADS)

Pugazhendhi, S.; Kirubha, E.; Palanisamy, P. K.; Gopalakrishnan, R.

2015-12-01

Development of green route for the synthesis of nanoparticles with plant extracts plays a very important role in nanotechnology without any toxicity chemicals. Herein we report a new approach to synthesize silver nanoparticles (AgNPs) using aqueous extract of Alpinia calcarata root as a reducing as well as stabilizing agent. The crystal structure and purity of the synthesized AgNPs were studied using Powder X-ray Diffraction analysis. The Surface Plasmon Resonance bands of synthesized silver nanoparticles have been obtained and monitored using UV-Visible spectrum. The morphologies of the AgNPs were analyzed using High resolution transmission electron microscopy (HRTEM). The elements present in the A. calcarata extract were determined by the inductively coupled plasma-optical emission Spectrometry (ICP-OES) and Fourier transform infrared spectroscopy (FTIR). Silver nanoparticles from A. calcarata possess very good antimicrobial activity which was confirmed by resazurin dye reduction assay method and thus it is a potential source of antimicrobial agent. The synthesized Ag nanoparticles exhibit good optical nonlinearity and the nonlinear optical studies have been carried out by Z-scan technique.

Synthesis, crystal structure and spectroscopic and electrochemical properties of bridged trisbenzoato copper-zinc heterobinuclear complex of 2,2‧-bipyridine

NASA Astrophysics Data System (ADS)

Koch, Angira; Kumar, Arvind; Singh, Suryabhan; Borthakur, Rosmita; Basumatary, Debajani; Lal, Ram A.; Shangpung, Sankey

2015-03-01

The synthesis of the heterobinuclear copper-zinc complex [CuZn(bz)3(bpy)2]ClO4 (bz = benzoate) from benzoic acid and bipyridine is described. Single crystal X-ray diffraction studies of the heterobinuclear complex reveals the geometry of the benzoato bridged Cu(II)-Zn(II) centre. The copper or zinc atom is pentacoordinate, with two oxygen atoms from bridging benzoato groups and two nitrogen atoms from one bipyridine forming an approximate plane and a bridging oxygen atom from a monodentate benzoate group. The Cu-Zn distance is 3.345 Å. The complex is normal paramagnetic having μeff value equal to 1.75 BM, ruling out the possibility of Cu-Cu interaction in the structural unit. The ESR spectrum of the complex in CH3CN at RT exhibit an isotropic four line spectrum centred at g = 2.142 and hyperfine coupling constants Aav = 63 × 10-4 cm-1, characteristic of a mononuclear square-pyramidal copper(II) complexes. At LNT, the complex shows an isotropic spectrum with g|| = 2.254 and g⊥ = 2.071 and A|| = 160 × 10-4 cm-1. The Hamiltonian parameters are characteristic of distorted square pyramidal geometry. Cyclic voltammetric studies of the complex have indicated quasi-reversible behaviour in acetonitrile solution.

Sleep in children with autism spectrum disorder.

PubMed

Kotagal, Suresh; Broomall, Eileen

2012-10-01

Children with autism spectrum disorder demonstrate an increased prevalence of difficulties with sleep initiation and maintenance. The consequences may include alterations in daytime behavior, memory, and learning in patients, and significant stress in caretakers. The dysregulation of melatonin synthesis, sensitization to environmental stimuli, behavioral insomnia syndromes, delayed sleep phase syndrome, rapid eye movement sleep behavior disorder, and comorbid anxiety, depression, and epilepsy comprise common etiologic factors. The clinical assessment of sleep problems in this population and a management algorithm are presented. Copyright © 2012 Elsevier Inc. All rights reserved.

Research on Spectroscopy, Opacity, and Atmospheres

NASA Technical Reports Server (NTRS)

Oliversen, Ronald (Technical Monitor); Kurucz, Robert L.

2004-01-01

I propose to continue providing observers with basic data for interpreting spectra from stars, novas, supernovas, clusters, and galaxies. These data will include allowed forbidden line lists both laboratory and computed, for the first five to ten ions of all atoms and for all relevant diatomic molecules. I will eventually expend to all ions of the first thirty elements to treat far UV end X-ray spectra, and for envelope opacities. I also include triatomic molecules providing by other researchers. I have made CDs with Partridge and Schwanke's water data for work on M stars.The luna data also serve as input to my model atmosphere and synthesis programs that generated energy distributions, photometry, limb darkening, and spectra that can be used for planning observations and for fitting observed spectra. The spectrum synthesis programs produce detailed plots with the line identified. Grids of stellar spectra can be used for radial velocity-, rotation-, or abundance templates and for population synthesis. I am fitting spectra of bright stars to test the data and to produce atlases to guide observer. For each star the whole spectrum is computed from the UV to the far IR. The line data, opacities, models, spectra, and programs are freely distributed on CDs and on my web site and represent a unique resource for many NASA programs.

HR8844: a new hot Am star?

NASA Astrophysics Data System (ADS)

Monier, R.; Gebran, M.; Royer, F.

2016-12-01

Using one archival high dispersion high quality spectrum of HR8844 (A0V) obtained with the echelle spectrograph SOPHIE at Observatoire de Haute Provence, we show that this star is not a superficially normal A0V star as hitherto thought. The model atmosphere and spectrum synthesis modeling of the spectrum of HR8844 reveals large departures of its abundances from the solar composition. We report here on our first determinations of the elemental abundances of 41 elements in the atmosphere of HR8844. Most of the light elements are underabundant whereas the very heavy elements are overabundant in HR8844. This interesting new chemically peculiar star could be a hybrid object between the HgMn stars and the Am stars.

R-Baclofen Reverses a Social Behavior Deficit and Elevated Protein Synthesis in a Mouse Model of Fragile X Syndrome.

PubMed

Qin, Mei; Huang, Tianjian; Kader, Michael; Krych, Leland; Xia, Zengyan; Burlin, Thomas; Zeidler, Zachary; Zhao, Tingrui; Smith, Carolyn B

2015-03-28

Fragile X syndrome (FXS) is the most common known inherited form of intellectual disability and the single genomic cause of autism spectrum disorders. It is caused by the absence of a fragile X mental retardation gene (Fmr1) product, FMRP, an RNA-binding translation suppressor. Elevated rates of protein synthesis in the brain and an imbalance between synaptic signaling via glutamate and γ-aminobutyric acid (GABA) are both considered important in the pathogenesis of FXS. In a mouse model of FXS (Fmr1 knockout [KO]), treatment with R-baclofen reversed some behavioral and biochemical phenotypes. A remaining crucial question is whether R-baclofen is also able to reverse increased brain protein synthesis rates. To answer this question, we measured regional rates of cerebral protein synthesis in vivo with the L-[1-(14)C]leucine method in vehicle- and R-baclofen-treated wildtype and Fmr1 KO mice. We further probed signaling pathways involved in the regulation of protein synthesis. Acute R-baclofen administration corrected elevated protein synthesis and reduced deficits on a test of social behavior in adult Fmr1 KO mice. It also suppressed activity of the mammalian target of rapamycin pathway, particularly in synaptosome-enriched fractions, but it had no effect on extracellular-regulated kinase 1/2 activity. Ninety min after R-baclofen treatment, we observed an increase in metabotropic glutamate receptor 5 expression in the frontal cortex, a finding that may shed light on the tolerance observed in human studies with this drug. Our results suggest that treatment via activation of the GABA (GABA receptor subtype B) system warrants further study in patients with FXS. Published by Oxford University Press on behalf of CINP 2015. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Surface-modified multifunctional MIP nanoparticles

NASA Astrophysics Data System (ADS)

Moczko, Ewa; Poma, Alessandro; Guerreiro, Antonio; Perez de Vargas Sansalvador, Isabel; Caygill, Sarah; Canfarotta, Francesco; Whitcombe, Michael J.; Piletsky, Sergey

2013-04-01

The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors.The synthesis of core-shell molecularly imprinted polymer nanoparticles (MIP NPs) has been performed using a novel solid-phase approach on immobilised templates. The same solid phase also acts as a protective functionality for high affinity binding sites during subsequent derivatisation/shell formation. This procedure allows for the rapid synthesis, controlled separation and purification of high-affinity materials, with each production cycle taking just 2 hours. The aim of this approach is to synthesise uniformly sized imprinted materials at the nanoscale which can be readily grafted with various polymers without affecting their affinity and specificity. For demonstration purposes we grafted anti-melamine MIP NPs with coatings which introduce the following surface characteristics: high polarity (PEG methacrylate); electro-activity (vinylferrocene); fluorescence (eosin acrylate); thiol groups (pentaerythritol tetrakis(3-mercaptopropionate)). The method has broad applicability and can be used to produce multifunctional imprinted nanoparticles with potential for further application in the biosensors, diagnostics and biomedical fields and as an alternative to natural receptors. Electronic supplementary information (ESI) available: Details of the synthesis of eosin O-acrylate monomer and 1H-NMR spectrum of MIP NPs post-derivatised with PEG shell. See DOI: 10.1039/c3nr00354j

Wet chemical synthesis and luminescence in Ca5(PO4)3M:Eu2+ (M = Br, I) phosphors for solid state lighting

NASA Astrophysics Data System (ADS)

Mungmode, C. D.; Gahane, D. H.; Moharil, S. V.

2018-05-01

A simple wet chemical synthesis of Eu2+ activated Ca5(PO4)3Br and Ca5(PO4)3I phosphors and their photoluminescence is reported. Formation of Ca5(PO4)3Br is confirmed by X-ray diffraction (XRD). Synthesized phosphors are analyzed for photoluminescence (PL) spectrum. A bright blue emission is observed when phosphors are excited by near Ultra Violet (nUV) radiations. Photoluminescence emission spectrum for (Ca0.985Eu0.015)5(PO4)3Br is centered at 457 nm and for (Ca0.985Eu0.015)5(PO4)3 I it peaks at 455 nm when excited by 365 nm near UV radiation. Eu2+ luminescence in Ca5(PO4)3Br is reported for the first time. The phosphors can be efficiently excited by nUV radiations. This shows that phosphors may be used as blue phosphor in pcLED for Solid State Lighting.

Axinellamines as Broad-Spectrum Antibacterial Agents: Scalable Synthesis and Biology

PubMed Central

2015-01-01

Antibiotic-resistant bacteria present an ongoing challenge to both chemists and biologists as they seek novel compounds and modes of action to out-maneuver continually evolving resistance pathways, especially against Gram-negative strains. The dimeric pyrrole–imidazole alkaloids represent a unique marine natural product class with diverse primary biological activity and chemical architecture. This full account traces the strategy used to develop a second-generation route to key spirocycle 9, culminating in a practical synthesis of the axinellamines and enabling their discovery as broad-spectrum antibacterial agents, with promising activity against both Gram-positive and Gram-negative bacteria. While their detailed mode of antibacterial action remains unclear, the axinellamines appear to cause secondary membrane destabilization and impart an aberrant cellular morphology consistent with the inhibition of normal septum formation. This study serves as a rare example of a natural product initially reported to be devoid of biological activity surfacing as an active antibacterial agent with an intriguing mode of action. PMID:25328977

Simultaneous synthesis of single-walled carbon nanotubes and graphene in a magnetically-enhanced arc plasma.

PubMed

Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

2012-02-02

Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising application for molecular sensors, field effect transistor and super thin and flexible electronic devices(1-4). Anodic arc discharge supported by the erosion of the anode material is one of the most practical and efficient methods, which can provide specific non-equilibrium processes and a high influx of carbon material to the developing structures at relatively higher temperature, and consequently the as-synthesized products have few structural defects and better crystallinity. To further improve the controllability and flexibility of the synthesis of carbon nanostructures in arc discharge, magnetic fields can be applied during the synthesis process according to the strong magnetic responses of arc plasmas. It was demonstrated that the magnetically-enhanced arc discharge can increase the average length of SWCNT (5), narrow the diameter distribution of metallic catalyst particles and carbon nanotubes (6), and change the ratio of metallic and semiconducting carbon nanotubes (7), as well as lead to graphene synthesis (8). Furthermore, it is worthwhile to remark that when we introduce a non-uniform magnetic field with the component normal to the current in arc, the Lorentz force along the J×B direction can generate the plasmas jet and make effective delivery of carbon ion particles and heat flux to samples. As a result, large-scale graphene flakes and high-purity single-walled carbon nanotubes were simultaneously generated by such new magnetically-enhanced anodic arc method. Arc imaging, scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy were employed to analyze the characterization of carbon nanostructures. These findings indicate a wide spectrum of opportunities to manipulate with the properties of nanostructures produced in plasmas by means of controlling the arc conditions.

Simultaneous Synthesis of Single-walled Carbon Nanotubes and Graphene in a Magnetically-enhanced Arc Plasma

PubMed Central

Li, Jian; Shashurin, Alexey; Kundrapu, Madhusudhan; Keidar, Michael

2012-01-01

Carbon nanostructures such as single-walled carbon nanotubes (SWCNT) and graphene attract a deluge of interest of scholars nowadays due to their very promising application for molecular sensors, field effect transistor and super thin and flexible electronic devices1-4. Anodic arc discharge supported by the erosion of the anode material is one of the most practical and efficient methods, which can provide specific non-equilibrium processes and a high influx of carbon material to the developing structures at relatively higher temperature, and consequently the as-synthesized products have few structural defects and better crystallinity. To further improve the controllability and flexibility of the synthesis of carbon nanostructures in arc discharge, magnetic fields can be applied during the synthesis process according to the strong magnetic responses of arc plasmas. It was demonstrated that the magnetically-enhanced arc discharge can increase the average length of SWCNT 5, narrow the diameter distribution of metallic catalyst particles and carbon nanotubes 6, and change the ratio of metallic and semiconducting carbon nanotubes 7, as well as lead to graphene synthesis 8. Furthermore, it is worthwhile to remark that when we introduce a non-uniform magnetic field with the component normal to the current in arc, the Lorentz force along the J×B direction can generate the plasmas jet and make effective delivery of carbon ion particles and heat flux to samples. As a result, large-scale graphene flakes and high-purity single-walled carbon nanotubes were simultaneously generated by such new magnetically-enhanced anodic arc method. Arc imaging, scanning electron microscope (SEM), transmission electron microscope (TEM) and Raman spectroscopy were employed to analyze the characterization of carbon nanostructures. These findings indicate a wide spectrum of opportunities to manipulate with the properties of nanostructures produced in plasmas by means of controlling the arc conditions. PMID:22330847

A molecular cross-linking approach for hybrid metal oxides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, Dahee; Saleh, Liban A. M.; Berkson, Zachariah J.

Developing methods to create hybrid materials to maximize their transformative capabilities has been the subject of significant interest. In particular, several key methods have been developed to manipulate earth abundant metal oxides such as TiO 2 to produce hybrid materials with improved or new properties relevant to a broad spectrum of applications. Here, we introduce a new approach we refer to as “molecular doping”, whereby a hybrid molecular boron oxide material is formed from polyhedral boron cluster precursors of the type [B 12(OH) 12] 2-. This new approach is enabled by the inherent robustness of the boron cluster molecular buildingmore » block, which is compatible with harsh thermal and oxidizing conditions that are necessary for the synthesis of many metal oxides. In this work, we show how this material can be successfully interfaced with TiO 2, resulting in boron-rich hybrid materials with unprecedented photophysical and electrochemical properties.« less

A new simple synthesis of CdS nano-particles by composite-molten-salt method and their high photocatalytic degradation activity

NASA Astrophysics Data System (ADS)

Xiang, Donghu; Zhu, Yabo; Cai, Cunjin; He, Zhanjun; Liu, Zhangsheng; Yin, Dagen; Luo, Jin

2011-12-01

Nano-CdS crystal has been succesfully synthesized by composite molten salt (CMS) method for the first time, using composite molten salt as a reaction solvent, sodium sulfide and cadmium nitrate hexahydrate as reactants at temperature of 200 °C for 24 h in the absence of organic dispersant or capping agents. X-ray diffraction and field emission scanning electron microscopy (FESEM) images indicated that the as-synthesized product were well crystallized and belonged to nano-scale. Their UV-vis absorption spectrum demonstrated a band gap of 2.49 eV corresponding to the absorption edge of 499 nm. The experimental result of photocatalytic degradation on methyl orange by the nano-CdS showed much better photocatalysis than that by the commercial CdS powder under the irradiation of ultraviolet light source.

A novel graphene oxide-polyimide as optical waveguide material: Synthesis and thermo-optic switch properties

NASA Astrophysics Data System (ADS)

Cao, Tianlin; Zhao, Fanyu; Da, Zulin; Qiu, Fengxian; Yang, Dongya; Guan, Yijun; Cao, Guorong; Zhao, Zerun; Li, Jiaxin; Guo, Xiaotong

2016-10-01

In this work, a novel graphene oxide-polyimide (GOPI) as optical waveguide material was prepared. The structure, mechanical, thermal property and morphology of the GOPI was characterized by using fourier transform infrared, UV-visible spectroscopy, near-infrared spectrum, thermogravimetric analysis, differential scanning calorimetry, scanning electron microscope and transmission electron microscopy. The thermo-optic coefficients (dn/dT) are -9.16 × 10-4 (532 nm), -7.56 × 10-4 (650 nm) and -4.82 × 10-4 (850 nm) °C-1, respectively. Based on the thermo-optic effect of prepared GOPI as waveguide material, a Y-branch with branching angle of 0.143° and Mach-Zehnder thermo-optic switches were designed. Using finite difference beam propagation method (FD-BPM) method, the simulation results such as power consumptions and response times of two different thermo-optic switches were obtained.

Approaches toward a blue semiconductor laser

NASA Technical Reports Server (NTRS)

Ladany, I.

1989-01-01

Possible approaches for obtaining semiconductor diode laser action in the blue region of the spectrum are surveyed. A discussion of diode lasers is included along with a review of the current status of visible emitters, presently limited to 670 nm. Methods are discussed for shifting laser emission toward shorter wavelengths, including the use of II-IV materials, the increase in the bandgap of III-V materials by addition of nitrogen, and changing the bandstructure from indirect to direct by incorporating interstitial atoms or by constructing superlattices. Non-pn-junction injection methods are surveyed, including avalanche breakdown, Langmuir-Blodgett diodes, heterostructures, carrier accumulation, and Berglund diodes. Prospects of inventing new multinary semiconducting materials are discussed, and a number of novel materials described in the literature are tabulated. New approaches available through the development of quantum wells and superlattices are described, including resonant tunneling and the synthesis of arbitrary bandgap materials through multiple quantum wells.

Mutations causing syndromic autism define an axis of synaptic pathophysiology.

PubMed

Auerbach, Benjamin D; Osterweil, Emily K; Bear, Mark F

2011-11-23

Tuberous sclerosis complex and fragile X syndrome are genetic diseases characterized by intellectual disability and autism. Because both syndromes are caused by mutations in genes that regulate protein synthesis in neurons, it has been hypothesized that excessive protein synthesis is one core pathophysiological mechanism of intellectual disability and autism. Using electrophysiological and biochemical assays of neuronal protein synthesis in the hippocampus of Tsc2(+/-) and Fmr1(-/y) mice, here we show that synaptic dysfunction caused by these mutations actually falls at opposite ends of a physiological spectrum. Synaptic, biochemical and cognitive defects in these mutants are corrected by treatments that modulate metabotropic glutamate receptor 5 in opposite directions, and deficits in the mutants disappear when the mice are bred to carry both mutations. Thus, normal synaptic plasticity and cognition occur within an optimal range of metabotropic glutamate-receptor-mediated protein synthesis, and deviations in either direction can lead to shared behavioural impairments.

Knowledge synthesis methods for integrating qualitative and quantitative data: a scoping review reveals poor operationalization of the methodological steps.

PubMed

Tricco, Andrea C; Antony, Jesmin; Soobiah, Charlene; Kastner, Monika; MacDonald, Heather; Cogo, Elise; Lillie, Erin; Tran, Judy; Straus, Sharon E

2016-05-01

To describe and compare, through a scoping review, emerging knowledge synthesis methods for integrating qualitative and quantitative evidence in health care, in terms of expertise required, similarities, differences, strengths, limitations, and steps involved in using the methods. Electronic databases (e.g., MEDLINE) were searched, and two reviewers independently selected studies and abstracted data for qualitative analysis. In total, 121 articles reporting seven knowledge synthesis methods (critical interpretive synthesis, integrative review, meta-narrative review, meta-summary, mixed studies review, narrative synthesis, and realist review) were included after screening of 17,962 citations and 1,010 full-text articles. Common similarities among methods related to the entire synthesis process, while common differences related to the research question and eligibility criteria. The most common strength was a comprehensive synthesis providing rich contextual data, whereas the most common weakness was a highly subjective method that was not reproducible. For critical interpretive synthesis, meta-narrative review, meta-summary, and narrative synthesis, guidance was not provided for some steps of the review process. Some of the knowledge synthesis methods provided guidance on all steps, whereas other methods were missing guidance on the synthesis process. Further work is needed to clarify these emerging knowledge synthesis methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Extracellular synthesis of silver nanoparticles using the leaf extract of Coleus amboinicus Lour

DOE Office of Scientific and Technical Information (OSTI.GOV)

Narayanan, Kannan Badri; Sakthivel, Natarajan, E-mail: puns2005@gmail.com

2011-10-15

Highlights: {yields} Synthesis of AgNPs using the leaf extract of Coleus amboinicus L. was described. {yields} UV-vis absorption spectra showed the formation of isotrophic AgNPs at 437 nm in 6 h. {yields} XRD analysis showed intense peaks corresponding to fcc structure of AgNPs. {yields} HR-TEM analysis revealed the formation of stable anisotrophic and isotrophic AgNPs. -- Abstract: In the present investigation, Coleus amboinicus Lour. leaf extract-mediated green chemistry approach for the synthesis of silver nanoparticles was described. The nanoparticles were characterized by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), Fourier transform infrared spectroscopy (FTIR) and transmissionmore » electron microscopy (TEM). The influence of leaf extract on the control of size and shape of silver nanoparticles is reported. Upon an increase in the concentration of leaf extract, there was a shift in the shape of nanoparticles from anisotrophic nanostructures like triangle, decahedral and hexagonal to isotrophic spherical nanoparticles. Crystalline nature of fcc structured nanoparticles was confirmed by XRD spectrum with peaks corresponding to (1 1 1), (2 0 0), (2 2 0) and (3 1 1) planes and bright circular spots in the selected-area electron diffraction (SAED). Such environment friendly and sustainable methods are non-toxic, cheap and alternative to hazardous chemical procedures.« less

Shape- and Size-Controlled Synthesis of Silver Nanoparticles Using Aloe vera Plant Extract and Their Antimicrobial Activity

NASA Astrophysics Data System (ADS)

Logaranjan, Kaliyaperumal; Raiza, Anasdass Jaculin; Gopinath, Subash C. B.; Chen, Yeng; Pandian, Kannaiyan

2016-11-01

Biogenic synthesis of silver nanoparticles (AgNP) was performed at room temperature using Aloe vera plant extract in the presence of ammoniacal silver nitrate as a metal salt precursor. The formation of AgNP was monitored by UV-visible spectroscopy at different time intervals. The shape and size of the synthesized particle were visualized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. These results were confirmed by X-ray powder diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses and further supported by surface-enhanced Raman spectroscopy/Raman scattering (SERS) study. UV-visible spectrum has shown a sharp peak at 420 nm and further evidenced by FTIR peak profile (at 1587.6, 1386.4, and 1076 cm-1 with corresponding compounds). The main band position with SERS was noticed at 1594 cm-1 (C-C stretching vibration). When samples were heated under microwave radiation, AgNP with octahedron shapes with 5-50 nm were found and this method can be one of the easier ways to synthesis anisotropic AgNP, in which the plant extract plays a vital role to regulate the size and shape of the nanoparticles. Enhanced antibacterial effects (two- to fourfold) were observed in the case of Aloe vera plant protected AgNP than the routinely synthesized antibiotic drugs.

Synthesis and Characterization of a New Co-Crystal Explosive with High Energy and Good Sensitivity

NASA Astrophysics Data System (ADS)

Gao, Han; Jiang, Wei; Liu, Jie; Hao, Gazi; Xiao, Lei; Ke, Xiang; Chen, Teng

2017-10-01

A new energetic co-crystal consisting of one of the most powerful explosive molecules 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the military explosive cyclotrimethylenetrinitramine (RDX) was prepared with a simple solvent evaporation method. Scanning electron microscopy (SEM) revealed the morphology of the bar-shaped product, which differed greatly from the morphology of the individual components. Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction spectrum (XRD), and differential scanning calorimetry (DSC) proved the formation of the co-crystal at the molecular level. The result of mechanical sensitivity test indicated the sensitivity was effectively reduced compared to raw CL-20. Finally, a possible crystallization mechanism was discussed.

Synthesis, characterization and relativistic DFT studies of fac-Re(CO)3(isonicotinic acid)2Cl complex

NASA Astrophysics Data System (ADS)

Zúñiga, César; Oyarzún, Diego P.; Martin-Transaco, Rudy; Yáñez-S, Mauricio; Tello, Alejandra; Fuentealba, Mauricio; Cantero-López, Plinio; Arratia-Pérez, Ramiro

2017-11-01

In this work, new fac-Re(CO)3(PyCOOH)2Cl from isonicotinic acid ligand has been prepared. The complex was characterized by structural (single-crystal X-ray diffraction), elemental analysis and spectroscopic (FTIR, NMR, UV-vis spectroscopy) methods. DFT and TDDFT calculations were performed to obtain the electronic transitions involved in their UV-Vis spectrum. The excitation energies agree with the experimental results. The TDDFT calculations suggest that experimental mixed absorption bands at 270 and 314 nm could be assigned to (MLCT-LLCT)/MLCT transitions. Natural Bond Orbitals (NBO) approach has enabled studying the effects of bonding interactions. E(2) energies confirm the occurrence of ICT (Intra-molecular Charge Transfer) within the molecule.

Effect of Fe doping concentration on photocatalytic activity of ZnO nanosheets under natural sunlight

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khokhra, Richa; Kumar, Rajesh, E-mail: rajesh.kumar@juit.ac.in

2015-05-15

A facile room temperature, aqueous solution-based chemical method has been adopted for large-scale synthesis of Fe doped ZnO nanosheets. The XRD and SEM results reveal the as-synthesized products well crystalline and accumulated by large amount of interweave nanosheets, respectively. Energy dispersive spectroscopy data confirmed Fe doping of the ZnO nanosheets with a varying Fe concentration. The photoluminescence spectrum reveals a continuous suppression of defect related emissions intensity by increasing the concentration of the Fe ion. A photocatalytic activity using these samples under sunlight irradiation in the mineralization of methylene blue dye was investigated. The photocatalytic activity of Fe doped ZnOmore » nanosheets depends upon the presence of surface oxygen vacancies.« less

Synthesis and characterization of bactericidal silver nanoparticles using cultural filtrate of simulated microgravity grown Klebsiella pneumoniae.

PubMed

Kalpana, Duraisamy; Lee, Yang Soo

2013-03-05

Silver nanoparticles were synthesized by biological method using cultural filtrate of Klebsiella pneumoniae cultured under simulated microgravity and silver nitrate solution as precursor. The nanoparticles exhibited typical plasmon absorption maximum of silver nanoparticles between 405 and 407 nm. Spherical silver nanoparticles were found to have size between 15 and 37 nm by TEM analysis. XRD pattern corresponding to planes (111), (200), (220) (311) revealed the crystalline nature of the biosynthesized silver nanoparticles. FTIR spectrum proposed stabilization of silver nanoparticles by the protein molecules present in the cultural filtrate. The silver nanoparticles exhibited high bactericidal activity against Salmonella enterica, Escherichia coli and moderate bactericidal activity against Streptococcus pyogenes. Copyright © 2012 Elsevier Inc. All rights reserved.

Electron emission produced by photointeractions in a slab target

NASA Technical Reports Server (NTRS)

Thinger, B. E.; Dayton, J. A., Jr.

1973-01-01

The current density and energy spectrum of escaping electrons generated in a uniform plane slab target which is being irradiated by the gamma flux field of a nuclear reactor are calculated by using experimental gamma energy transfer coefficients, electron range and energy relations, and escape probability computations. The probability of escape and the average path length of escaping electrons are derived for an isotropic distribution of monoenergetic photons. The method of estimating the flux and energy distribution of electrons emerging from the surface is outlined, and a sample calculation is made for a 0.33-cm-thick tungsten target located next to the core of a nuclear reactor. The results are to be used as a guide in electron beam synthesis of reactor experiments.

Synthesis and characterization of a new zinc(II) complex with tetradentate azo-thioether ligand: X-ray structure, DNA binding study and DFT calculation

NASA Astrophysics Data System (ADS)

Mondal, Apurba Sau; Pramanik, Ajoy Kumar; Patra, Lakshman; Manna, Chandan Kumar; Mondal, Tapan Kumar

2017-10-01

A new zinc(II) complex, [Zn(L)(H2O)](ClO4) (1) with azo-thioether containing NSNO donor ligand, 3-(2-(2-((pyridin-2-ylmethyl)thio)phenyl)hydrazono)pentane-2,4-dione (HL) is synthesized and characterized by several spectroscopic techniques. The distorted square based pyramidal (DSBP) geometry is confirmed by single crystal X-ray structure. The ability of the complex to bind with CT DNA is investigated by UV-vis method and the binding constant is found to be 4.16 × 104 M-1. Competitive binding study with ethidium bromide (EB) by fluorescence method suggests that the zinc(II) complex efficiently displaces EB from EB-DNA. The Stern-Volmer dynamic quenching constant, Ksv is found to be 1.2 × 104 M-1. Theoretical calculations by DFT and TDDFT/CPCM methods are used to interpret the electronic structure and UV-vis spectrum of the complex.

Portable method of measuring gaseous acetone concentrations.

PubMed

Worrall, Adam D; Bernstein, Jonathan A; Angelopoulos, Anastasios P

2013-08-15

Measurement of acetone in human breath samples has been previously shown to provide significant non-invasive diagnostic insight into the control of a patient's diabetic condition. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetone, which are then exhaled during respiration. Using various breath analysis methods has allowed for the accurate determination of acetone concentrations in exhaled breath. However, many of these methods require instrumentation and pre-concentration steps not suitable for point-of-care use. We have found that by immobilizing resorcinol reagent into a perfluorosulfonic acid polymer membrane, a controlled organic synthesis reaction occurs with acetone in a dry carrier gas. The immobilized, highly selective product of this reaction (a flavan) is found to produce a visible spectrum color change which could measure acetone concentrations to less than ppm. We here demonstrate how this approach can be used to produce a portable optical sensing device for real-time, non-invasive acetone analysis. Copyright © 2013 Elsevier B.V. All rights reserved.

Structural characterization of Er(3+),Yb(3+)-doped Gd2O3 phosphor, synthesized using the solid-state reaction method, and its luminescence behavior.

PubMed

Tamrakar, Raunak Kumar; Bisen, D P; Brahme, Nameeta

2016-02-01

We report the synthesis and structural characterization of Er(3+),Yb(3+)-doped Gd2O3 phosphor. The sample was prepared using the conventional solid-state reaction method, which is the most suitable method for large-scale production. The prepared phosphor sample was characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), thermoluminescence (TL), photoluminescence (PL) and CIE techniques. For PL studies, the excitation and emission spectra of Gd2O3 phosphor doped with Er(3+) and Yb(3+) were recorded. The excitation spectrum was recorded at a wavelength of 551 nm and showed an intense peak at 276 nm. The emission spectrum was recorded at 276 nm excitation and showed peaks in all blue, green and red regions, which indicate that the prepared phosphor may act as a single host for white light-emitting diode (WLED) applications, as verified by International de I'Eclairage (CIE) techniques. From the XRD data, the calculated average crystallite size of Er(3+) and Yb(3+) -doped Gd2O3 phosphor is ~ 38 nm. A TL study was carried out for the phosphor using UV irradiation. The TL glow curve was recorded for UV, beta and gamma irradiations, and the kinetic parameters were also calculated. In addition, the trap parameters of the prepared phosphor were also studied using computerized glow curve deconvolution (CGCD). Copyright © 2015 John Wiley & Sons, Ltd.

Microcomputer-Based Digital Signal Processing Laboratory Experiments.

ERIC Educational Resources Information Center

Tinari, Jr., Rocco; Rao, S. Sathyanarayan

1985-01-01

Describes a system (Apple II microcomputer interfaced to flexible, custom-designed digital hardware) which can provide: (1) Fast Fourier Transform (FFT) computation on real-time data with a video display of spectrum; (2) frequency synthesis experiments using the inverse FFT; and (3) real-time digital filtering experiments. (JN)

Butyrate enhances disease resistance of chickens by inducing antimicrobial host defense peptide gene expression

USDA-ARS?s Scientific Manuscript database

Host defense peptides (HDPs) constitute a large group of natural broad-spectrum antimicrobials and an important first line of immunity in virtually all forms of life. Specific augmentation of synthesis of endogenous HDPs may represent a promising antibiotic-alternative approach to disease control. I...

Sweet and Sustainable: Teaching the Biorefinery Concept through Biobased Gelator Synthesis

ERIC Educational Resources Information Center

Hwang, Hyeondo Luke; Jadhav, Swapnil Rohidas; Silverman, Julian Robert; John, George

2014-01-01

Undergraduate curricula have increasingly incorporated sustainable and environmentally friendly approaches in the laboratory. Learning outcomes have emphasized the importance of the principles of green chemistry, but experiments may fail to impress upon the students that large-scale conversions of biomass into a spectrum of value-added products…

Fast radio burst search: cross spectrum vs. auto spectrum method

NASA Astrophysics Data System (ADS)

Liu, Lei; Zheng, Weimin; Yan, Zhen; Zhang, Juan

2018-06-01

The search for fast radio bursts (FRBs) is a hot topic in current radio astronomy studies. In this work, we carry out a single pulse search with a very long baseline interferometry (VLBI) pulsar observation data set using both auto spectrum and cross spectrum search methods. The cross spectrum method, first proposed in Liu et al., maximizes the signal power by fully utilizing the fringe phase information of the baseline cross spectrum. The auto spectrum search method is based on the popular pulsar software package PRESTO, which extracts single pulses from the auto spectrum of each station. According to our comparison, the cross spectrum method is able to enhance the signal power and therefore extract single pulses from data contaminated by high levels of radio frequency interference (RFI), which makes it possible to carry out a search for FRBs in regular VLBI observations when RFI is present.

Lithium Abundance in M3 Red Giant

NASA Astrophysics Data System (ADS)

Givens, Rashad; Pilachowski, Catherine A.

2015-01-01

We present the abundance of lithium in the red giant star vZ 1050 (SK 291) in the globular cluster M3. A previous survey of giants in the cluster showed that like IV-101, vZ 1050 displays a prominent Li I 6707 Å feature. vZ 1050 lies on the blue side of the red giant branch about 1.3 magnitudes above the level of the horizontal branch, and may be an asymptotic giant branch star. A high resolution spectrum of M3 vZ1050 was obtained with the ARC 3.5m telescope and the ARC Echelle Spectrograph (ARCES). Atmospheric parameters were determined using Fe I and Fe II lines from the spectrum using the MOOG spectral analysis program, and the lithium abundance was determined using spectrum synthesis.

Structural Amendment and Stereoselective Synthesis of Mutisianthol.

PubMed

Ho, Tse-Lok; Lee, Kwang-Yuan; Chen, Chun-Kuei

1997-05-16

cis-1-(5-Acetoxy-3,6-dimethyl-1-indanyl)-2-methyl-1-propene synthesized from 3,6-dimethyl-1-indanone was found to be different from mutisianthol by spectral comparison. The presence of a high-field signal in the NMR spectrum of the final product and various intermediates, characteristic of the cis-1,3-dialkylindanes but absent in the spectrum of the natural terpene, suggests a revision of the structure of mutisianthol to the trans isomer. The trans-indane which was subsequently obtained indeed exhibits data fully agreeable with mutisianthol. A similar stereochemical revision for jungianol is also indicated.

Hyperfine Structure and Abundances of Heavy Elements in 68 Tauri (HD 27962)

NASA Astrophysics Data System (ADS)

Martinet, S.; Monier, R.

2017-12-01

HD 27962, also known as 68 Tauri, is a Chemically Peculiar Am star member of the Hyades Open Cluster in the local arm of the Galaxy. We have modeled the high resolution SOPHIE (R=75000) spectrum of 68 Tauri using updated model atmosphere and spectrum synthesis to derive chemical abundances in its atmosphere. In particular, we have studied the effect of the inclusion of Hyperfine Structure of various Baryum isotopes on the determination of the Baryum abundance in 68 Tauri. We have also derived new abundances using updated accurate atomic parameters retrieved from the NIST database.

Synthesis and characterization of binary (CuO)0.6(CeO2)0.4 nanoparticles via a simple heat treatment method

NASA Astrophysics Data System (ADS)

Baqer, Anwar Ali; Matori, Khamirul Amin; Al-Hada, Naif Mohammed; Shaari, Abdul Halim; Kamari, Halimah Mohamed; Saion, Elias; Chyi, Josephine Liew Ying; Abdullah, Che Azurahanim Che

2018-06-01

A binary (CuO)0.6 (CeO2)0.4 nanoparticles were prepared via thermal treatment method, using copper nitrate, cerium nitrate as precursors, PVP as capping agent and de-ionized water as a solvent. The structures, morphology, composition of the element and optical properties of these nanoparticles have been studied under different temperatures using various techniques. The XRD spectrum of the samples at 500 °C and above confirmed the existence of both monoclinic (CuO) and cubic fluorite (CeO2) structures. The findings of FESEM and TEM exhibited the average practical size and agglomeration increment with an elevation in the calcination temperature. The synthesized nanoparticles were also characterized by FTIR, which indicated the formation of binary Cu-O and Ce-O bonds. The EDX analysis was performed to indicate the chemical composition of the sample. The double energy band gaps of (CuO)0.6(CeO2)0.4 reduction with rising calcination temperature, can be referred to the enhancement of the crystallinity of the samples. PL intensity of (CuO)0.6(CeO2)0.4 nanoparticles peaks, which increased with the elevation of the calcination temperature to 800 °C was observed from the PL spectrum; this was due to the increment of the particle size that occurred.

V-doped SnS2: a new intermediate band material for a better use of the solar spectrum.

PubMed

Wahnón, Perla; Conesa, José C; Palacios, Pablo; Lucena, Raquel; Aguilera, Irene; Seminovski, Yohanna; Fresno, Fernando

2011-12-07

Intermediate band materials can boost photovoltaic efficiency through an increase in photocurrent without photovoltage degradation thanks to the use of two sub-bandgap photons to achieve a full electronic transition from the valence band to the conduction band of a semiconductor structure. After having reported in previous works several transition metal-substituted semiconductors as able to achieve the electronic structure needed for this scheme, we propose at present carrying out this substitution in sulfides that have bandgaps of around 2.0 eV and containing octahedrally coordinated cations such as In or Sn. Specifically, the electronic structure of layered SnS(2) with Sn partially substituted by vanadium is examined here with first principles quantum methods and seen to give favourable characteristics in this respect. The synthesis of this material in nanocrystalline powder form is then undertaken and achieved using solvothermal chemical methods. The insertion of vanadium in SnS(2) is found to produce an absorption spectrum in the UV-Vis-NIR range that displays a new sub-bandgap feature in agreement with the quantum calculations. A photocatalytic reaction-based test verifies that this sub-bandgap absorption produces highly mobile electrons and holes in the material that may be used for the solar energy conversion, giving experimental support to the quantum calculations predictions.

Data analysis of “krokodil” samples obtained by street-like synthesis

PubMed Central

Neves, João Filipe; Alves, Emanuele Amorim; Soares, José Xavier; Cravo, Sara Manuela; Silva, Artur M.S.; Pereira Netto, Annibal Duarte; Carvalho, Félix; Dinis-Oliveira, Ricardo Jorge; Afonso, Carlos Manuel

2015-01-01

The data described in this work is related to be the subject of an article in the Forensic Science International, titled: “The harmful chemistry behind “krokodil”: street-like synthesis and product analysis” (http://dx.doi.org/10.1016/j.forsciint.2015.07.042) [1]. The data presented here provides additional description of the chemical profile of “krokodil”. Physicochemical and organoleptic characteristics, TLC profile, UV/Vis, 1H NMR and FTIR spectrum are presented. These data validate the proposed synthetic procedure and pathway and give further information about the contaminants present in “krokodil”. PMID:26958624

Synthesis of Five‐Porphyrin Nanorings by Using Ferrocene and Corannulene Templates

PubMed Central

Liu, Pengpeng; Hisamune, Yutaka; Peeks, Martin D.; Odell, Barbara; Gong, Juliane Q.; Herz, Laura M.

2016-01-01

Abstract The smallest and most strained member of a family of π‐conjugated cyclic porphyrin oligomers was synthesized by using pentapyridyl templates based on ferrocene and corannulene. Both templates are effective for directing the synthesis of the butadiyne‐linked cyclic pentamer, despite the fact that the radii of their N5 donor sets are too small by 0.5 Å and 0.9 Å, respectively (from DFT calculations). The five‐porphyrin nanoring exhibits a structured absorption spectrum and its fluorescence extends to 1200 nm, reflecting strong π conjugation and Herzberg–Teller vibronic coupling. PMID:27213825

Copper(II)-catalyzed enantioselective hydrosilylation of halo-substituted alkyl aryl and heteroaryl ketones: asymmetric synthesis of (R)-fluoxetine and (S)-duloxetine.

PubMed

Zhou, Ji-Ning; Fang, Qiang; Hu, Yi-Hu; Yang, Li-Yao; Wu, Fei-Fei; Xie, Lin-Jie; Wu, Jing; Li, Shijun

2014-02-14

A set of reaction conditions has been established to facilitate the non-precious copper-catalyzed enantioselective hydrosilylation of a number of structurally diverse β-, γ- or ε-halo-substituted alkyl aryl ketones and α-, β- or γ-halo-substituted alkyl heteroaryl ketones under air to afford a broad spectrum of halo alcohols in high yields and good to excellent enantioselectivities (up to 99% ee). The developed procedure has been successfully applied to the asymmetric synthesis of antidepressant drugs (R)-fluoxetine and (S)-duloxetine, which highlighted its synthetic utility.

Green chemistry approach for the synthesis of biocompatible graphene

PubMed Central

Gurunathan, Sangiliyandi; Han, Jae Woong; Kim, Jin-Hoi

2013-01-01

Background Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms isolated from its three-dimensional parent material, graphite. One of the most common methods for preparation of graphene is chemical exfoliation of graphite using powerful oxidizing agents. Generally, graphene is synthesized through deoxygenation of graphene oxide (GO) by using hydrazine, which is one of the most widespread and strongest reducing agents. Due to the high toxicity of hydrazine, it is not a promising reducing agent in large-scale production of graphene; therefore, this study focused on a green or sustainable synthesis of graphene and the biocompatibility of graphene in primary mouse embryonic fibroblast cells (PMEFs). Methods Here, we demonstrated a simple, rapid, and green chemistry approach for the synthesis of reduced GO (rGO) from GO using triethylamine (TEA) as a reducing agent and stabilizing agent. The obtained TEA reduced GO (TEA-rGO) was characterized by ultraviolet (UV)–visible absorption spectroscopy, X-ray diffraction (XRD), particle size dynamic light scattering (DLS), scanning electron microscopy (SEM), Raman spectroscopy, and atomic force microscopy (AFM). Results The transition of graphene oxide to graphene was confirmed by UV–visible spectroscopy. XRD and SEM were used to investigate the crystallinity of graphene and the surface morphologies of prepared graphene respectively. The formation of defects further supports the functionalization of graphene as indicated in the Raman spectrum of TEA-rGO. Surface morphology and the thickness of the GO and TEA-rGO were analyzed using AFM. The presented results suggest that TEA-rGO shows significantly more biocompatibility with PMEFs cells than GO. Conclusion This is the first report about using TEA as a reducing as well as a stabilizing agent for the preparation of biocompatible graphene. The proposed safe and green method offers substitute routes for large-scale production of graphene for several biomedical applications. PMID:23940417

A facile biomimetic preparation of highly stabilized silver nanoparticles derived from seed extract of Vigna radiata and evaluation of their antibacterial activity

NASA Astrophysics Data System (ADS)

Choudhary, Manoj Kumar; Kataria, Jyoti; Cameotra, Swaranjit Singh; Singh, Jagdish

2016-01-01

The significant antibacterial activity of silver nanoparticles draws the major attention toward the present nanobiotechnology. Also, the use of plant material for the synthesis of metal nanoparticles is considered as a green technology. In this context, a non-toxic, eco-friendly, and cost-effective method has been developed for the synthesis of silver nanoparticles using seed extract of mung beans ( Vigna radiata). The synthesized nanoparticles have been characterized by UV-visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), atomic absorption spectroscopy (AAS), and X-ray diffraction (XRD). The UV-visible spectrum showed an absorption peak at around 440 nm. The different types of phytochemicals present in the seed extract synergistically reduce the Ag metal ions, as each phytochemical is unique in terms of its structure and antioxidant function. The colloidal silver nanoparticles were observed to be highly stable, even after 5 months. XRD analysis showed that the silver nanoparticles are crystalline in nature with face-centered cubic geometry and the TEM micrographs showed spherical particles with an average size of 18 nm. Further, the antibacterial activity of silver nanoparticles was evaluated by well-diffusion method and it was observed that the biogenic silver nanoparticles have an effective antibacterial activity against Escherichia coli and Staphylococcus aureus. The outcome of this study could be useful for nanotechnology-based biomedical applications.

Comparative Modelling of the Spectra of Cool Giants

NASA Technical Reports Server (NTRS)

Lebzelter, T.; Heiter, U.; Abia, C.; Eriksson, K.; Ireland, M.; Neilson, H.; Nowotny, W; Maldonado, J; Merle, T.; Peterson, R.;

Metal Nanoparticle Catalysts for Carbon Nanotube Growth

NASA Technical Reports Server (NTRS)

Pierce, Benjamin F.

2003-01-01

Work this summer involved and new and unique process for producing the metal nanoparticle catalysts needed for carbon nanotube (CNT) growth. There are many applications attributed to CNT's, and their properties have deemed them to be a hot spot in research today. Many groups have demonstrated the versatility in CNT's by exploring a wide spectrum of roles that these nanotubes are able to fill. A short list of such promising applications are: nanoscaled electronic circuitry, storage media, chemical sensors, microscope enhancement, and coating reinforcement. Different methods have been used to grow these CNT's. Some examples are laser ablation, flame synthesis, or furnace synthesis. Every single approach requires the presence of a metal catalyst (Fe, Co, and Ni are among the best) that is small enough to produce a CNT. Herein lies the uniqueness of this work. Microemulsions (containing inverse micelles) were used to generate these metal particles for subsequent CNT growth. The goal of this summer work was basically to accomplish as much preliminary work as possible. I strived to pinpoint which variable (experimental process, metal product, substrate, method of application, CVD conditions, etc.) was the determining factor in the results. The resulting SEM images were sufficient for the appropriate comparisons to be made. The future work of this project consists of the optimization of the more promising experimental procedures and further exploration onto what exactly dictated the results.

Adsorption of VOCs on reduced graphene oxide.

PubMed

Yu, Lian; Wang, Long; Xu, Weicheng; Chen, Limin; Fu, Mingli; Wu, Junliang; Ye, Daiqi

2018-05-01

A modified Hummer's method was adopted for the synthesis of graphene oxide (GO) and reduced graphene oxide (rGO). It was revealed that the modified method is effective for the production of GO and rGO from graphite. Transmission electron microscopy (TEM) images of GO and rGO showed a sheet-like morphology. Because of the presence of oxygenated functional groups on the carbon surface, the interlayer spacing of the prepared GO was higher than that of rGO. The presence of OH and CO groups in the Fourier transform infrared spectra (FTIR) spectrum and G-mode and 2D-mode in Raman spectra confirmed the synthesis of GO and rGO. rGO (292.6m 2 /g) showed higher surface area than that of GO (236.4m 2 /g). The prepared rGO was used as an adsorbent for benzene and toluene (model pollutants of volatile organic compounds (VOCs)) under dynamic adsorption/desorption conditions. rGO showed higher adsorption capacity and breakthrough times than GO. The adsorption capacity of rGO for benzene and toluene was 276.4 and 304.4mg/g, respectively. Desorption experiments showed that the spent rGO can be successfully regenerated by heating at 150.0°C. Its excellent adsorption/desorption performance for benzene and toluene makes rGO a potential adsorbent for VOC adsorption. Copyright © 2017. Published by Elsevier B.V.

Single step synthesis of rutile TiO{sub 2} nanoflower array film by chemical bath deposition method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dhandayuthapani, T.; Sivakumar, R.; Ilangovan, R., E-mail: rilangovan@yahoo.com

2016-05-06

Titanium oxide (TiO{sub 2}) nanostructures such as nanorod arrays, nanotube arrays and nanoflower arrays have been extensively investigated by the researchers. Among them nanoflower arrays has shown superior performance than other nanostructures in Dye sensitized solar cell, photocatalysis and energy storage applications. Herein, a single step synthesis for rutile TiO{sub 2} nanoflower array films suitable for device applications has been reported. Rutile TiO{sub 2} nanoflower thin film was synthesized by chemical bath deposition method using NaCl as an additive. Bath temperature induced evolution of nanoflower thin film arrays was observed from the morphological study. X-ray diffraction study confirmed the presencemore » of rutile phase polycrystalline TiO{sub 2}. Micro-Raman study revealed the presence of surface phonon mode at 105 cm{sup −1} due to the phonon confinement effect (finite size effect), in addition with the rutile Raman active modes of B{sub 1}g (143 cm{sup −1}), Eg (442 cm{sup −1}) and A{sub 1}g (607 cm{sup −1}). Further, the FTIR spectrum confirmed the presence of Ti-O-Ti bonding vibration. The Tauc plot showed the direct energy band gap nature of the film with the value of 2.9 eV.« less

Seed-free synthesis of 1D silver nanowires ink using clove oil (Syzygium Aromaticum) at room temperature.

PubMed

Jeevika, Alagan; Ravi Shankaran, Dhesingh

2015-11-15

Silver nanowires (AgNWs) have been demonstrated to be a promising next generation conducting material and an alternative to the traditional electrode (ITO) because of its high conductivity, transparency and stability. Generally, AgNWs are synthesized by chemical method (mainly polyol reduction method) at high temperature in the presence of exotic seeds. The present work aims at the green approach for preparation and characterization of 1D AgNWs ink using clove oil (Syzygium Aromaticum) at room temperature. AgNWs was prepared by green synthesis using clove oil as reducing as well as capping agent at room temperature. The obtained ink was purified, filtered and redissolved in methanol. The prepared AgNWs showed an absorption peaks at 350 and 387nm in the UV-vis spectrum due to transverse SPR mode of silver. From the HR-TEM analysis, it was observed that the AgNWs possess an average diameter and length of ∼39±0.01nm and ∼3μm, respectively. The obtained AgNWs are crystalline in nature and are arranged in a perfect crystal lattice orientation, which was confirmed from the selected area electron diffraction studies. Moreover, the X-ray diffraction analysis confirms the face centered cubic structure. The AgNWs coated glass substrate shows an electrical conductivity of ∼0.48×10(6)S/m. Copyright © 2015 Elsevier Inc. All rights reserved.

Musical sound analysis/synthesis using vector-quantized time-varying spectra

NASA Astrophysics Data System (ADS)

Ehmann, Andreas F.; Beauchamp, James W.

2002-11-01

A fundamental goal of computer music sound synthesis is accurate, yet efficient resynthesis of musical sounds, with the possibility of extending the synthesis into new territories using control of perceptually intuitive parameters. A data clustering technique known as vector quantization (VQ) is used to extract a globally optimum set of representative spectra from phase vocoder analyses of instrument tones. This set of spectra, called a Codebook, is used for sinusoidal additive synthesis or, more efficiently, for wavetable synthesis. Instantaneous spectra are synthesized by first determining the Codebook indices corresponding to the best least-squares matches to the original time-varying spectrum. Spectral index versus time functions are then smoothed, and interpolation is employed to provide smooth transitions between Codebook spectra. Furthermore, spectral frames are pre-flattened and their slope, or tilt, extracted before clustering is applied. This allows spectral tilt, closely related to the perceptual parameter ''brightness,'' to be independently controlled during synthesis. The result is a highly compressed format consisting of the Codebook spectra and time-varying tilt, amplitude, and Codebook index parameters. This technique has been applied to a variety of harmonic musical instrument sounds with the resulting resynthesized tones providing good matches to the originals.

Mitochondrial Dysfunction and Its Relationship with mTOR Signaling and Oxidative Damage in Autism Spectrum Disorders.

PubMed

Yui, Kunio; Sato, Atsushi; Imataka, George

2015-01-01

Mitochondria are organelles that play a central role in processes related to cellular viability, such as energy production, cell growth, cell death via apoptosis, and metabolism of reactive oxygen species (ROS). We can observe behavioral abnormalities relevant to autism spectrum disorders (ASDs) and their recovery mediated by the mTOR inhibitor rapamycin in mouse models. In Tsc2(+/-) mice, the transcription of multiple genes involved in mTOR signaling is enhanced, suggesting a crucial role of dysregulated mTOR signaling in the ASD model. This review proposes that the mTOR inhibitor may be useful for the pharmacological treatment of ASD. This review offers novel insights into mitochondrial dysfunction and the related impaired glutathione synthesis and lower detoxification capacity. Firstly, children with ASD and concomitant mitochondrial dysfunction have been reported to manifest clinical symptoms similar to those of mitochondrial disorders, and it therefore shows that the clinical manifestations of ASD with a concomitant diagnosis of mitochondrial dysfunction are likely due to these mitochondrial disorders. Secondly, the adenosine triphosphate (ATP) production/oxygen consumption pathway may be a potential candidate for preventing mitochondrial dysfunction due to oxidative stress, and disruption of ATP synthesis alone may be related to impaired glutathione synthesis. Finally, a decrease in total antioxidant capacity may account for ASD children who show core social and behavioral impairments without neurological and somatic symptoms.

Effectiveness of Sleep-Based Interventions for Children with Autism Spectrum Disorder: A Meta-Synthesis.

PubMed

Cuomo, Belinda M; Vaz, Sharmila; Lee, Elinda Ai Lim; Thompson, Craig; Rogerson, Jessica M; Falkmer, Torbjorn

2017-05-01

Sleep problems are common in children with autism spectrum disorder (ASD). This meta-synthesis collated eight previously published systematic reviews examining the efficacy of sleep interventions in children with ASD in an attempt to present a clear analysis of trialed interventions. The collated reviews consider five major groups of sleep interventions for children with ASD: melatonin therapy, pharmacologic treatments other than melatonin, behavioral interventions, parent education/education programs, and alternative therapies (massage therapy, aromatherapy, and multivitamin and iron supplementation). These eight reviews were based on 38 original studies and address the efficacy of interventions across 17 sleep problem domains. The results of this meta-synthesis suggest that no single intervention is effective across all sleep problems in children with ASD. However, melatonin, behavioral interventions, and parent education/education program interventions appear the most effective at ameliorating multiple domains of sleep problems compared with other interventions. Due to the heterogeneous causative factors and presentations of disordered sleep, further research into the effectiveness of sleep interventions may target specific phenotypic subgroups rather than a broad analysis across the general ASD population. Similarly, future research needs to consider the efficacy of different polytherapeutic approaches in order to provide clinicians with evidence to inform best practice. In the meantime, this review supports clinicians' decision making for a majority of the identified sleep problems in the ASD population. © 2017 Pharmacotherapy Publications, Inc.

A review on green synthesis of silver nanoparticles and their applications.

PubMed

Rafique, Muhammad; Sadaf, Iqra; Rafique, M Shahid; Tahir, M Bilal

2017-11-01

Development of reliable and eco-accommodating methods for the synthesis of nanoparticles is a vital step in the field of nanotechnology. Silver nanoparticles are important because of their exceptional chemical, physical, and biological properties, and hence applications. In the last decade, numerous efforts were made to develop green methods of synthesis to avoid the hazardous byproducts. This review describes the methods of green synthesis for Ag-NPs and their numerous applications. It also describes the comparison of efficient synthesis methods via green routes over physical and chemical methods, which provide strong evidence for the selection of suitable method for the synthesis of Ag-NPs.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

PubMed Central

Feng, Pengju; Ngai, Ming-Yu

2016-01-01

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 °C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials. PMID:26862864

A spectrum fractal feature classification algorithm for agriculture crops with hyper spectrum image

NASA Astrophysics Data System (ADS)

Su, Junying

2011-11-01

A fractal dimension feature analysis method in spectrum domain for hyper spectrum image is proposed for agriculture crops classification. Firstly, a fractal dimension calculation algorithm in spectrum domain is presented together with the fast fractal dimension value calculation algorithm using the step measurement method. Secondly, the hyper spectrum image classification algorithm and flowchart is presented based on fractal dimension feature analysis in spectrum domain. Finally, the experiment result of the agricultural crops classification with FCL1 hyper spectrum image set with the proposed method and SAM (spectral angle mapper). The experiment results show it can obtain better classification result than the traditional SAM feature analysis which can fulfill use the spectrum information of hyper spectrum image to realize precision agricultural crops classification.

Advancements in Research Synthesis Methods: From a Methodologically Inclusive Perspective

ERIC Educational Resources Information Center

Suri, Harsh; Clarke, David

2009-01-01

The dominant literature on research synthesis methods has positivist and neo-positivist origins. In recent years, the landscape of research synthesis methods has changed rapidly to become inclusive. This article highlights methodologically inclusive advancements in research synthesis methods. Attention is drawn to insights from interpretive,…

[A correction method of baseline drift of discrete spectrum of NIR].

PubMed

Hu, Ai-Qin; Yuan, Hong-Fu; Song, Chun-Feng; Li, Xiao-Yu

2014-10-01

In the present paper, a new correction method of baseline drift of discrete spectrum is proposed by combination of cubic spline interpolation and first order derivative. A fitting spectrum is constructed by cubic spline interpolation, using the datum in discrete spectrum as interpolation nodes. The fitting spectrum is differentiable. First order derivative is applied to the fitting spectrum to calculate derivative spectrum. The spectral wavelengths which are the same as the original discrete spectrum were taken out from the derivative spectrum to constitute the first derivative spectra of the discrete spectra, thereby to correct the baseline drift of the discrete spectra. The effects of the new method were demonstrated by comparison of the performances of multivariate models built using original spectra, direct differential spectra and the spectra pretreated by the new method. The results show that negative effects on the performance of multivariate model caused by baseline drift of discrete spectra can be effectively eliminated by the new method.

Near-Infrared Spectrum Detection of Wheat Gluten Protein Content Based on a Combined Filtering Method.

PubMed

Cai, Jian-Hua

2017-09-01

To eliminate the random error of the derivative near-IR (NIR) spectrum and to improve model stability and the prediction accuracy of the gluten protein content, a combined method is proposed for pretreatment of the NIR spectrum based on both empirical mode decomposition and the wavelet soft-threshold method. The principle and the steps of the method are introduced and the denoising effect is evaluated. The wheat gluten protein content is calculated based on the denoised spectrum, and the results are compared with those of the nine-point smoothing method and the wavelet soft-threshold method. Experimental results show that the proposed combined method is effective in completing pretreatment of the NIR spectrum, and the proposed method improves the accuracy of detection of wheat gluten protein content from the NIR spectrum.

Herbal Medicine Treatment for Children with Autism Spectrum Disorder: A Systematic Review

PubMed Central

Lu, Hsu Yuan

2017-01-01

Objective To summarize and evaluate the efficacy and safety of herbal medicines used for the treatment of autism spectrum disorder (ASD) in children. Methods Thirteen electronic databases were searched from their inception to November 2016. Randomized controlled trials (RCTs) that assessed the efficacy of herbal medicines alone or in combination with other Traditional Chinese Medicine treatments for ASD in children were included. The Cochrane Risk of Bias Tool was used and other data analyses were performed using RevMan (Version 5.3). Results Ten RCTs involving 567 patients with ASD were included for qualitative synthesis. In conjunction with conventional therapy, herbal medicines significantly improved the Childhood Autism Rating Scale (CARS) score, but the results of effects on total effective rate (TER) were different between the included studies. The use of herbal medicines with integrative therapy improved the CARS score and TER. In the studies that documented adverse events, no serious events were associated with herbal medicines. Conclusions The efficacy of herbal medicines for the treatment of ASD appears to be encouraging but was inconclusive owing to low methodological quality, herbal medicine diversity, and small sample size of the examined studies. PMID:28592982

Synthesis Structural and Optical Properties Of (Co, Al) co-doped ZnO Nano Particles

NASA Astrophysics Data System (ADS)

Swapna, P.; Venkatramana Reddy, S.

2018-02-01

We prepared (Co, Al) co-doped ZnO nanostructures using the method chemical co-precipitation successfully, at room temperature using PEG (Poly ethylene glycol) as stabilizing agent. Samples are prepared with different concentrations by keeping aluminium at 5 mol percent constant and varying the concentration of cobalt from 1 to 5 mol percent. After the preparation all the samples are carefully subjected to characterizations such as XRD, SEM with EDS, TEM, PL and UV-VIS-NIR. XRD pattern shows that all the samples possess hexagonal wurtzite crystal structure having no secondary phases pertaining to Al or cobalt, which shows successful dissolution of the dopents. TEM results shows the accurate size of particles and is confirmed the XRD data. SEM images of all the samples shows that particles are in nearly spherical shape, EDS spectrum reveals that incorporation of cobalt and aluminum in host lattice. PL spectrum shows that all the samples containing two prominent peaks centered at 420 nm and 446 nm. UV-VIS-NIR spectra has shown three absorptions peaks in the range of wavelength 550 nm to 700 nm, which are ascribed as typical d-d transitions of cobalt ions.

A new stellar spectrum interpolation algorithm and its application to Yunnan-III evolutionary population synthesis models

NASA Astrophysics Data System (ADS)

Cheng, Liantao; Zhang, Fenghui; Kang, Xiaoyu; Wang, Lang

2018-05-01

In evolutionary population synthesis (EPS) models, we need to convert stellar evolutionary parameters into spectra via interpolation in a stellar spectral library. For theoretical stellar spectral libraries, the spectrum grid is homogeneous on the effective-temperature and gravity plane for a given metallicity. It is relatively easy to derive stellar spectra. For empirical stellar spectral libraries, stellar parameters are irregularly distributed and the interpolation algorithm is relatively complicated. In those EPS models that use empirical stellar spectral libraries, different algorithms are used and the codes are often not released. Moreover, these algorithms are often complicated. In this work, based on a radial basis function (RBF) network, we present a new spectrum interpolation algorithm and its code. Compared with the other interpolation algorithms that are used in EPS models, it can be easily understood and is highly efficient in terms of computation. The code is written in MATLAB scripts and can be used on any computer system. Using it, we can obtain the interpolated spectra from a library or a combination of libraries. We apply this algorithm to several stellar spectral libraries (such as MILES, ELODIE-3.1 and STELIB-3.2) and give the integrated spectral energy distributions (ISEDs) of stellar populations (with ages from 1 Myr to 14 Gyr) by combining them with Yunnan-III isochrones. Our results show that the differences caused by the adoption of different EPS model components are less than 0.2 dex. All data about the stellar population ISEDs in this work and the RBF spectrum interpolation code can be obtained by request from the first author or downloaded from http://www1.ynao.ac.cn/˜zhangfh.

Mechano-chemical synthesis K2MF6 (M = Mn, Ni) by cation-exchange reaction at room temperature

NASA Astrophysics Data System (ADS)

Rawat, Pooja; Nagarajan, Rajamani

2018-02-01

In order to establish the power of mechanochemistry to produce industrially important phosphors, synthesis of K2MnF6 has been attempted by the successive grinding reactions of manganese (II) acetate with ammonium fluoride and potassium fluoride. The progress of reaction was followed by ex-situ characterization after periodic intervals of time. Cubic symmetry of K2MnF6 was evident from its powder X-ray diffraction pattern which was refined successfully in cubic space group (Fm-3m) with a = 8.4658 (20) Å. Stretching and bending vibration modes of MnF62- octahedral units appeared at 740 and 482 cm-1 in the fourier transformed infrared spectrum. Bands at 405 and 652 cm-1 appeared in the Raman spectrum and they were finger-print positions of cubic K2MnF6. Other than the ligand to metal charge transfer transition at 242 nm, transitions from 4A2g to 4T1g, 4T2g and 2T2g of Mn4+-ion appeared at 352, 429, 474 and 569 nm in the UV-visible diffuse reflectance spectrum of the sample. Red emission due to Mn4+ was observed in the photoluminescence spectrum with a decay time of 0.22 ms. Following the success in forming cubic K2MnF6, this approach has been extended to synthesize cubic K2NiF6 at room temperature. All these results confirmed the susceptibility of acetate salts of transition metals belonging to first-row of the periodic table to facile fluorination at room temperature aided by mechanical forces.

A bias-adjusted evidence synthesis of RCT and observational data: the case of total hip replacement.

PubMed

Schnell-Inderst, Petra; Iglesias, Cynthia P; Arvandi, Marjan; Ciani, Oriana; Matteucci Gothe, Raffaella; Peters, Jaime; Blom, Ashley W; Taylor, Rod S; Siebert, Uwe

2017-02-01

Evaluation of clinical effectiveness of medical devices differs in some aspects from the evaluation of pharmaceuticals. One of the main challenges identified is lack of robust evidence and a will to make use of experimental and observational studies (OSs) in quantitative evidence synthesis accounting for internal and external biases. Using a case study of total hip replacement to compare the risk of revision of cemented and uncemented implant fixation modalities, we pooled treatment effect estimates from OS and RCTs, and simplified existing methods for bias-adjusted evidence synthesis to enhance practical application. We performed an elicitation exercise using methodological and clinical experts to determine the strength of beliefs about the magnitude of internal and external bias affecting estimates of treatment effect. We incorporated the bias-adjusted treatment effects into a generalized evidence synthesis, calculating both frequentist and Bayesian statistical models. We estimated relative risks as summary effect estimates with 95% confidence/credibility intervals to capture uncertainty. When we compared alternative approaches to synthesizing evidence, we found that the pooled effect size strongly depended on the inclusion of observational data as well as on the use bias-adjusted estimates. We demonstrated the feasibility of using observational studies in meta-analyses to complement RCTs and incorporate evidence from a wider spectrum of clinically relevant studies and healthcare settings. To ensure internal validity, OS data require sufficient correction for confounding and selection bias, either through study design and primary analysis, or by applying post-hoc bias adjustments to the results. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd. © 2017 The Authors. Health Economics published by John Wiley & Sons, Ltd.

Facile green synthesis of silver nanoparticles using seed aqueous extract of Pistacia atlantica and its antibacterial activity

NASA Astrophysics Data System (ADS)

Sadeghi, Babak; Rostami, Amir; Momeni, S. S.

2015-01-01

In the present work, we describe the synthesis of silver nanoparticles (Ag-NPs) using seed aqueous extract of Pistacia atlantica (PA) and its antibacterial activity. UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) were performed to ascertain the formation of Ag-NPs. It was observed that the growths of Ag-NPs are stopped within 35 min of reaction time. The synthesized Ag-NPs were characterized by a peak at 446 nm in the UV-visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 27 nm size. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (1 1 1), (2 0 0), (2 2 0) and (3 1 1) Bragg's reflections of cubic structure of metallic silver, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of used drugs against bacterial diseases. The scanning electron microscopy (SEM), indicated that, the most strains of S. aureus was damaged and extensively disappeared by addition of Ag-NPs. The results confirmed that the (PA) is a very good eco friendly and nontoxic source for the synthesis of Ag-NPs as compared to the conventional chemical/physical methods.

Facile green synthesis of silver nanoparticles using seed aqueous extract of Pistacia atlantica and its antibacterial activity.

PubMed

Sadeghi, Babak; Rostami, Amir; Momeni, S S

2015-01-05

In the present work, we describe the synthesis of silver nanoparticles (Ag-NPs) using seed aqueous extract of Pistacia atlantica (PA) and its antibacterial activity. UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) were performed to ascertain the formation of Ag-NPs. It was observed that the growths of Ag-NPs are stopped within 35 min of reaction time. The synthesized Ag-NPs were characterized by a peak at 446 nm in the UV-visible spectrum. XRD confirmed the crystalline nature of the nanoparticles of 27 nm size. The XRD peaks at 38°, 44°, 64° and 77° can be indexed to the (111), (200), (220) and (311) Bragg's reflections of cubic structure of metallic silver, respectively. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of used drugs against bacterial diseases. The scanning electron microscopy (SEM), indicated that, the most strains of S. aureus was damaged and extensively disappeared by addition of Ag-NPs. The results confirmed that the (PA) is a very good eco friendly and nontoxic source for the synthesis of Ag-NPs as compared to the conventional chemical/physical methods. Copyright © 2014 Elsevier B.V. All rights reserved.

Low-cost and eco-friendly green synthesis of silver nanoparticles using Prunus japonica (Rosaceae) leaf extract and their antibacterial, antioxidant properties.

PubMed

Saravanakumar, Arthanari; Peng, Mei Mei; Ganesh, Mani; Jayaprakash, Jayabalan; Mohankumar, Murugan; Jang, Hyun Tae

2017-09-01

Low cost and eco-friendly green synthesis of silver nanoparticles (AgNPs) from silver nitrate (AgNO 3 ) using Prunus japonica leaves extract as reducing agent by a simple method at room temperature. The biosynthesized nanoparticles (NPs) were characterized by UV-Vis, tunneling electron microscopy (HR-TEM), scanning electron microscopy (SEM) coupled with X-ray energy dispersive spectrophotometer (EDAX), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). In UV-Vis spectroscopy results, the λ max was observed at 441 nm. The AgNPs synthesized were spherical, hexagonal, and irregular in shapes. The EDAX and XRD spectrum confirmed the presence of silver ions and crystalline nature of synthesized AgNPs. FTIR showed the functional groups such as C = O, N-H and C-N groups involved in the reduction of Ag +  to Ag. 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay was performed and it showed the percentage inhibition in concentration-dependent manner. The synthesized AgNPs showed antibacterial activity against Escherichia coli, Proteus vulgaris, Staphylococcus aureus and Bacillus cereus to different extents and the higher activity was observed in Proteus vulgaris.

Synthesis and biological activity of a new class of insecticides: the N-(5-aryl-1,3,4-thiadiazol-2-yl)amides.

PubMed

Eckelbarger, Joseph D; Parker, Marshall H; Yap, Maurice Ch; Buysse, Ann M; Babcock, Jonathan M; Hunter, Ricky; Adelfinskaya, Yelena; Samaritoni, Jack G; Garizi, Negar; Trullinger, Tony K

2017-04-01

Optimization studies on a high-throughput screening (HTS) hit led to the discovery of a series of N-(6-arylpyridazin-3-yl)amides with insecticidal activity. It was hypothesized that the isosteric replacement of the pyridazine ring with a 1,3,4-thiadiazole ring could lead to more potent biological activity and/or a broader sap-feeding pest spectrum. The resulting N-(5-aryl-1,3,4-thiadiazol-2-yl)amides were explored as a new class of insecticides. Several methods for 2-amino-1,3,4-thiadiazole synthesis were used for the preparation of key synthetic intermediates. Subsequent coupling to variously substituted carboxylic acid building blocks furnished the final targets, which were tested for insecticidal activity against susceptible strains of Aphis gossypii (Glover) (cotton aphid), Myzus persicae (Sulzer) (green peach aphid) and Bemisia tabaci (Gennadius) (sweetpotato whitefly). Structure-activity relationship (SAR) studies on both the amide tail and the aryl A-ring of novel N-(5-aryl-1,3,4-thiadiazol-2-yl)amides led to a new class of insecticidal molecules active against sap-feeding insect pests. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Synthesis and structure resolution of RbLaF4.

PubMed

Rollet, Anne-Laure; Allix, Mathieu; Veron, Emmanuel; Deschamps, Michael; Montouillout, Valérie; Suchomel, Matthew R; Suard, Emmanuelle; Barre, Maud; Ocaña, Manuel; Sadoc, Aymeric; Boucher, Florent; Bessada, Catherine; Massiot, Dominique; Fayon, Franck

2012-02-20

The synthesis and structure resolution of RbLaF(4) are described. RbLaF(4) is synthesized by solid-state reaction between RbF and LaF(3) at 425 °C under a nonoxidizing atmosphere. Its crystal structure has been resolved by combining neutron and synchrotron powder diffraction data refinements (Pnma,a = 6.46281(2) Å, b = 3.86498(1) Å, c = 16.17629(4) Å, Z = 4). One-dimensional (87)Rb, (139)La, and (19)F MAS NMR spectra have been recorded and are in agreement with the proposed structural model. Assignment of the (19)F resonances is performed on the basis of both (19)F-(139)La J-coupling multiplet patterns observed in a heteronuclear DQ-filtered J-resolved spectrum and (19)F-(87)Rb HMQC MAS experiments. DFT calculations of both the (19)F isotropic chemical shieldings and the (87)Rb, (139)La electric field gradient tensors using the GIPAW and PAW methods implemented in the CASTEP code are in good agreement with the experimental values and support the proposed structural model. Finally, the conductivity of RbLaF(4) and luminescence properties of Eu-doped LaRbF(4) are investigated.

Graphene Oxide from Carbon Rod Waste

NASA Astrophysics Data System (ADS)

Rahmawati, F.; Prasasti, B. L. W.; Mudjijono, M.

2018-03-01

Carbon rods extracted from Zn-C primary battery waste was used as raw material for graphene oxide (GO) synthesis. The synthesis used a modified Hummers method by providing potassium permanganate-sulfuric acid as the oxidizing agent. XRD analysis confirms a significant change between the graphite waste pattern and the produced graphene oxide pattern. A major peak at 2θ 27 ° which present in the graphite waste pattern is disappeared after it converts to the product, as well as a broad peak under 25 ° referring the presence of amorphous carbon. A broad peak at low angle of 12.02 ° dominantly present in the prepared GO pattern as a characteristic peak of GO. Meanwhile, some small peaks at 2θ of 17.76 °, 28.58 °, and 37.28 ° confirming the presence of manganese oxide which was used as oxidizing agent. A sharp peak at 1700 – 1500 cm-1 in the FT-IR spectrum indicates the presence of –C=O group, and at 1600 cm-1 refers to –C=C group. It confirms that this research has produced the targeted GO. Even though, the purity is need to be enhanced by removing the rest of oxidizing agent that still exist in the material.

One-pot template-free synthesis of porous CdMoO4 microspheres and their enhanced photocatalytic activity

NASA Astrophysics Data System (ADS)

Madhusudan, Puttaswamy; Zhang, Jinfeng; Yu, Jiaguo; Cheng, Bei; Xu, Difa; Zhang, Jun

2016-11-01

The optical and catalytic performances of materials strongly depend on their size, morphology, dimensionality and structure. Herein, we demonstrate a facile one-pot template free synthesis of hierarchical CdMoO4 porous microspheres via a simple low temperature oil bath method. The photoactivity of the as-prepared samples was evaluated by photocatalytic decolorization of Methyl Orange (MO) and Methylene Blue (MB) mixed dye aqueous solutions at ambient temperature under full solar spectrum. The results indicated that the concentration of ammonium molybdate and reaction time greatly influence the diameter, average crystallite size, specific surface area, pore structure and photocatalytic activity of the prepared samples. Especially, under the suitable conditions the prepared hierarchical CdMoO porous microspheres exhibited enhanced photocatalytic activity and high stability. Furthermore, it is found that the photocatalytic activity and formation rate of hydroxyl radicals greatly depend on the particle sizes and morphology of as-prepared samples. This work not only demonstrates a simple way to fabricate the hierarchical CdMoO4 porous microspheres but also shows a possibility for utilization of CdMoO4 porous microspheres for the photocatalytic treatment of waste water pollutants.

[Current trends in using PET radiopharmaceuticals for diagnostics in oncology].

PubMed

Adam, J; Kadeřávek, J; Kužel, F; Vašina, J; Rehák, Z

2014-01-01

Nuclear medicine is an important field of modern medicine, particularly thanks to its role in in vivo imaging of important processes in human organism. This is possible thanks to the use of radiopharmaceuticals, specific substances labeled by radioactive nuclide, its distribution in the body can be visualized by specialized scanners and, based on the knowledge of physiological patterns, dia-gnosis can be determined. Positron emission tomography (PET) is a modern and in many ways indispensable method of nuclear medicine. The spectrum of radiopharmaceuticals available in recent years is broadening thanks to a coordinated effort of manufacturers of synthesis equipment, chemists and potential users -  physicians. This review focuses on the development in the PET radiopharmaceutical field in the last five years, with an emphasis on oncological applications of PET.

Rotational spectroscopy of ClZnCH3 (X1A1): Gas-phase synthesis and characterization of a monomeric Grignard-type reagent

NASA Astrophysics Data System (ADS)

Min, J.; Bucchino, M. P.; Kilchenstein, K. M.; Ziurys, L. M.

2016-02-01

The pure rotational spectrum of the organozinc halide, ClZnCH3 (X1A1), has been measured using Fourier-transform microwave (FTMW) and millimeter-wave direct-absorption methods in the frequency range 10-296 GHz. This work is the first study of ClZnCH3 by gas-phase spectroscopy. The molecule was created in a DC discharge from the reaction of zinc vapor, produced either by a Broida-type oven or by laser ablation, with chloromethane in what appears to be a metal insertion process. Rotational and chlorine quadrupole constants were determined for three zinc isotopologues. The Znsbnd Cl bond was found to be partly ionic and significantly shorter than in EtZnCl.

First identification of O,S-diethyl Thiocarbonate in Indian Cress absolute and odor evaluation of its synthesized homologues by GC-sniffing.

PubMed

Breme, Katharina; Guillamon, Nadine; Fernandez, Xavier; Tournayre, Pascal; Brevard, Hugues; Joulain, Daniel; Berdagué, Jean Louis; Meierhenrich, Uwe J

2009-03-25

Indian cress (Tropaeolum majus L.) absolute was studied by GC-olfactometry (VIDEO-Sniff method) in order to identify odor-active aroma compounds. Because of its fruity-sulfury odor note, a compound that has never been identified in plant extracts before stood out: O,S-diethyl thiocarbonate, present at 0.1% (percentage of the total GC/FID area) in the extract. GCxGC-TOFMS allowed for a clean mass spectrum to be obtained, and isolation by preparative GC followed by NMR studies allowed its identification. Here, we report on the first detection of O,S-diethyl thiocarbonate in Indian cress absolute by GC-olfactometry/VIDEO-Sniff and on its isolation and identification. The synthesis and odor evaluation of its homologues are presented.

Synthesis and Characterization of Novel Fluorine-Containing Water-Based Antirust Coating

NASA Astrophysics Data System (ADS)

Wang, Huiru; Wang, Xin; Zhao, Xiongyan

2018-01-01

A fluorine-containing polyacrylate copolymer emulsion was synthesized by a seed emulsion polymerization method, in which styrene(St) and butyl acrylate (BA) were used as main monomers and dodecafluoroheptyl methacrylate(DFMA) as fluorine-containing monomer. The structure and properties were characterized by Fourier transform infrared spectrum (FT-IR), scanning electron microscopy (SEM), particle size analysis, differential scanning calorimetry (DSC). The FTIR results showed that DFMA was effectively involved in the emulsion copolymerization, and the formed emulsion particles had a narrow particle size distribution. From the results salt spray test presented, it seems when the content of DFMA was 5wt% anti-rust performance of emulsion is relatively better. DSC and TGA also showed that their film exhibited higher thermal stability than that of fluorine-free emulsion.

The role of habitat filtering in the leaf economics spectrum and plant susceptibility to pathogen infection

USGS Publications Warehouse

Welsh, Miranda E; Cronin, James P.; Mitchell, Charles E.

2016-01-01

5.Synthesis. Our results suggest that habitat filtering plays a fundamental role in strengthening the trait correlations of the LES, and that trait-based models may be less accurate when communities have not been filtered by the current environment, for example, following rapid environmental change.

Comparative “omics” of the Fusarium fujikuroi species complex highlights differences in genetic potential and metabolite synthesis

USDA-ARS?s Scientific Manuscript database

Species of the Fusarium fujikuroi species complex (FFC) cause a wide spectrum of often devastating diseases on diverse agricultural crops, including coffee, fig, mango, maize, rice, and sugarcane. Although species within the FFC are difficult to distinguish by morphology, and their genes often share...

Quantitative Synthesis and Component Analysis of Single-Participant Studies on the Picture Exchange Communication System

ERIC Educational Resources Information Center

Tincani, Matt; Devis, Kathryn

2011-01-01

The "Picture Exchange Communication System" (PECS) has emerged as the augmentative communication intervention of choice for individuals with autism spectrum disorder (ASD), with a supporting body of single-participant studies. This report describes a meta-analysis of 16 single-participant studies on PECS with percentage of nonoverlapping data…

Development of the Mental Synthesis Evaluation Checklist (MSEC): A Parent-Report Tool for Mental Synthesis Ability Assessment in Children with Language Delay

PubMed Central

Braverman, Julia; Dunn, Rita

2018-01-01

Mental synthesis is the conscious purposeful process of synthesizing novel mental images from objects stored in memory. Mental synthesis ability is essential for understanding complex syntax, spatial prepositions, and verb tenses. In typical children, the timeline of mental synthesis acquisition is highly correlated with an increasing vocabulary. Children with Autism Spectrum Disorder (ASD), on the other hand, may learn hundreds of words but never acquire mental synthesis. In these individuals, tests assessing vocabulary comprehension may fail to demonstrate the profound deficit in mental synthesis. We developed a parent-reported Mental Synthesis Evaluation Checklist (MSEC) designed to assess mental synthesis acquisition in ASD children. The psychometric quality of MSEC was tested with 3715 parents of ASD children. Internal reliability of the 20-item MSEC was good (Cronbach’s alpha >0.9). MSEC exhibited adequate test–retest reliability; good construct validity, supported by a positive correlation with the Autism Treatment Evaluation Checklist (ATEC) Communication subscale; and good known group validity reflected by the difference in MSEC scores for children of different ASD severity levels. The MSEC questionnaire is copyright-free and can be used by researchers as a complimentary subscale for the ATEC evaluation. We hope that the addition of MSEC will make the combined assessment more sensitive to small steps in a child’s development. As MSEC does not rely on productive language, it may be an especially useful tool for assessing the development of nonverbal and minimally verbal children. PMID:29783788

A COMPARISON OF EXPERIMENTS AND THREE-DIMENSIONAL ANALYSIS TECHNIQUES. PART II. UNPOISONED UNIFORM SLAB CORE WITH A PARTIALLY INSERTED HAFNIUM ROD AND A PARTIALLY INSERTED WATER GAP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roseberry, R.J.

The experimental measurements and nuclear analysis of a uniformly loaded, unpoisoned slab core with a partially inserted hafnium rod and/or a partially inserted water gap are described. Comparisons of experimental data with calculated results of the UFO core and flux synthesis techniques are given. It is concluded that one of the flux synthesis techniques and the UFO code are able to predict flux distributions to within approximately -5% of experiment for most cases, with a maximum error of approximately -10% for a channel at the core- reflector boundary. The second synthesis technique failed to give comparable agreement with experiment evenmore » when various refinements were used, e.g. increasing the number of mesh points, performing the flux synthesis technique of iteration, and spectrum-weighting the appropriate calculated fluxes through the use of the SWAKRAUM code. These results are comparable to those reported in Part I of this study. (auth)« less

Unsupervised malaria parasite detection based on phase spectrum.

PubMed

Fang, Yuming; Xiong, Wei; Lin, Weisi; Chen, Zhenzhong

2011-01-01

In this paper, we propose a novel method for malaria parasite detection based on phase spectrum. The method first obtains the amplitude spectrum and phase spectrum for blood smear images through Quaternion Fourier Transform (QFT). Then it gets the reconstructed image based on Inverse Quaternion Fourier transform (IQFT) on a constant amplitude spectrum and the original phase spectrum. The malaria parasite areas can be detected easily from the reconstructed blood smear images. Extensive experiments have demonstrated the effectiveness of this novel method.

Synthesis of silver nanoparticles using Dioscorea bulbifera tuber extract and evaluation of its synergistic potential in combination with antimicrobial agents

PubMed Central

Ghosh, Sougata; Patil, Sumersing; Ahire, Mehul; Kitture, Rohini; Kale, Sangeeta; Pardesi, Karishma; Cameotra, Swaranjit S; Bellare, Jayesh; Dhavale, Dilip D; Jabgunde, Amit; Chopade, Balu A

2012-01-01

Background Development of an environmentally benign process for the synthesis of silver nanomaterials is an important aspect of current nanotechnology research. Among the 600 species of the genus Dioscorea, Dioscorea bulbifera has profound therapeutic applications due to its unique phytochemistry. In this paper, we report on the rapid synthesis of silver nanoparticles by reduction of aqueous Ag+ ions using D. bulbifera tuber extract. Methods and results Phytochemical analysis revealed that D. bulbifera tuber extract is rich in flavonoid, phenolics, reducing sugars, starch, diosgenin, ascorbic acid, and citric acid. The biosynthesis process was quite fast, and silver nanoparticles were formed within 5 hours. Ultraviolet-visible absorption spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive spectroscopy, and x-ray diffraction confirmed reduction of the Ag+ ions. Varied morphology of the bioreduced silver nanoparticles included spheres, triangles, and hexagons. Optimization studies revealed that the maximum rate of synthesis could be achieved with 0.7 mM AgNO3 solution at 50°C in 5 hours. The resulting silver nanoparticles were found to possess potent antibacterial activity against both Gram-negative and Gram-positive bacteria. Beta-lactam (piperacillin) and macrolide (eryth-romycin) antibiotics showed a 3.6-fold and 3-fold increase, respectively, in combination with silver nanoparticles selectively against multidrug-resistant Acinetobacter baumannii. Notable synergy was seen between silver nanoparticles and chloramphenicol or vancomycin against Pseudomonas aeruginosa, and was supported by a 4.9-fold and 4.2-fold increase in zone diameter, respectively. Similarly, we found a maximum 11.8-fold increase in zone diameter of streptomycin when combined with silver nanoparticles against E. coli, providing strong evidence for the synergistic action of a combination of antibiotics and silver nanoparticles. Conclusion This is the first report on the synthesis of silver nanoparticles using D. bulbifera tuber extract followed by an estimation of its synergistic potential for enhancement of the antibacterial activity of broad spectrum antimicrobial agents. PMID:22334779

The Association of Birth Weight and Infant Growth with Energy Balance-Related Behavior – A Systematic Review and Best-Evidence Synthesis of Human Studies

PubMed Central

Chinapaw, Mai J. M.; Jansma, Elise P.; Vrijkotte, Tanja G. M.; Gemke, Reinoud J. B. J.

2017-01-01

Background Suboptimal prenatal and early postnatal growths are associated with obesity in later life, but the underlying mechanisms are unknown. The aim of this study was to systematically review the literature that reports on the longitudinal association of (i) birth size or (ii) infant growth with later (i) energy intake, (ii) eating behaviors, (iii) physical activity or (iv) sedentary behavior in humans. Methods A comprehensive search of MEDLINE, EMBASE, PsycINFO and The Cochrane Library was conducted to identify relevant publications. We appraised the methodological quality of the studies and synthesized the extracted data through a best-evidence synthesis. Results Data from 41 publications were included. The quality of the studies was high in three papers, moderate in 11 and low in the large majority (n = 27) of papers appraised. Our best-evidence synthesis indicates that there is no evidence for an association of birth weight with later energy intake, eating behavior, physical activity or sedentary behavior. We found moderate evidence for an association of extreme birth weights (at both ends of the spectrum) with lower physical activity levels at a later age. Evidence for the association of infant growth with energy balance-related behavior was generally insufficient. Conclusions We conclude that current evidence does not support an association of early-life growth with energy balance-related behaviors in later life, except for an association of extreme birth weights with later physical activity. PMID:28081150

"Pruning of biomolecules and natural products (PBNP)": an innovative paradigm in drug discovery.

PubMed

Bathula, Surendar Reddy; Akondi, Srirama Murthy; Mainkar, Prathama S; Chandrasekhar, Srivari

2015-06-21

The source or inspiration of many marketed drugs can be traced back to natural product research. However, the chemical structure of natural products covers a wide spectrum from very simple to complex. With more complex structures it is often desirable to simplify the molecule whilst retaining the desired biological activity. This approach seeks to identify the structural unit or pharmacophore responsible for the desired activity. Such pharmacophores have been the start point for a wide range of lead generation and optimisation programmes using techniques such as Biology Oriented Synthesis, Diversity Oriented Synthesis, Diverted Total Synthesis, and Fragment Based Drug Discovery. This review discusses the literature precedence of simplification strategies in four areas of natural product research: proteins, polysaccharides, nucleic acids, and compounds isolated from natural product extracts, and their impact on identifying therapeutic products.

Synthesis and Characterization of Cefotaxime Conjugated Gold Nanoparticles and Their Use to Target Drug-Resistant CTX-M-Producing Bacterial Pathogens.

PubMed

Shaikh, Sibhghatulla; Rizvi, Syed Mohd Danish; Shakil, Shazi; Hussain, Talib; Alshammari, Thamir M; Ahmad, Waseem; Tabrez, Shams; Al-Qahtani, Mohammad H; Abuzenadah, Adel M

2017-09-01

Multidrug-resistance due to "β lactamases having the expanded spectrum" (ESBLs) in members of Enterobacteriaceae is a matter of continued clinical concern. CTX-M is among the most common ESBLs in Enterobacteriaceae family. In the present study, a nanoformulation of cefotaxime was prepared using gold nanoparticles to combat drug-resistance in ESBL producing strains. Here, two CTX-M-15 positive cefotaxime resistant bacterial strains (i.e., one Escherichia coli and one Klebsiella pneumoniae strain) were used for testing the efficacy of "cefotaxime loaded gold-nanoparticles." Bromelain was used for both reduction and capping in the process of synthesis of gold-nanoparticles. Thereafter, cefotaxime was conjugated onto it with the help of activator 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide. For characterization of both unconjugated and cefotaxime conjugated gold nanoparticles; UV-Visible spectroscopy, Scanning, and Transmission type Electron Microscopy methods accompanied with Dynamic Light Scattering were used. We used agar diffusion method plus microbroth-dilution method for the estimation of the antibacterial-activity and determination of minimum inhibitory concentration or MIC values, respectively. MIC values of cefotaxime loaded gold nanoparticles against E. coli and K. pneumoniae were obtained as 1.009 and 2.018 mg/L, respectively. These bacterial strains were completely resistant to cefotaxime alone. These results reinforce the utility of conjugating an old unresponsive antibiotic with gold nanoparticles to restore its efficacy against otherwise resistant bacterial pathogens. J. Cell. Biochem. 118: 2802-2808, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

A study of transonic aerodynamic analysis methods for use with a hypersonic aircraft synthesis code

NASA Technical Reports Server (NTRS)

Sandlin, Doral R.; Davis, Paul Christopher

1992-01-01

A means of performing routine transonic lift, drag, and moment analyses on hypersonic all-body and wing-body configurations were studied. The analysis method is to be used in conjunction with the Hypersonic Vehicle Optimization Code (HAVOC). A review of existing techniques is presented, after which three methods, chosen to represent a spectrum of capabilities, are tested and the results are compared with experimental data. The three methods consist of a wave drag code, a full potential code, and a Navier-Stokes code. The wave drag code, representing the empirical approach, has very fast CPU times, but very limited and sporadic results. The full potential code provides results which compare favorably to the wind tunnel data, but with a dramatic increase in computational time. Even more extreme is the Navier-Stokes code, which provides the most favorable and complete results, but with a very large turnaround time. The full potential code, TRANAIR, is used for additional analyses, because of the superior results it can provide over empirical and semi-empirical methods, and because of its automated grid generation. TRANAIR analyses include an all body hypersonic cruise configuration and an oblique flying wing supersonic transport.

How Bacterial Pathogens Eat Host Lipids: Implications for the Development of Fatty Acid Synthesis Therapeutics*

PubMed Central

Yao, Jiangwei; Rock, Charles O.

2015-01-01

Bacterial type II fatty acid synthesis (FASII) is a target for the development of novel therapeutics. Bacteria incorporate extracellular fatty acids into membrane lipids, raising the question of whether pathogens use host fatty acids to bypass FASII and defeat FASII therapeutics. Some pathogens suppress FASII when exogenous fatty acids are present to bypass FASII therapeutics. FASII inhibition cannot be bypassed in many bacteria because essential fatty acids cannot be obtained from the host. FASII antibiotics may not be effective against all bacteria, but a broad spectrum of Gram-negative and -positive pathogens can be effectively treated with FASII inhibitors. PMID:25648887

Richard Schrock, Robert Grubbs, and Metathesis Method in Organic Synthesis

Science.gov Websites

Organic Synthesis Resources with Additional Information Richard R. Schrock of the Massachusetts Institute Nobel Prize in Chemistry "for the development of the metathesis method in organic synthesis" ] Chauvin, Grubbs and Schrock "for the development of the metathesis method in organic synthesis,"

IODOPSIN

PubMed Central

Wald, George; Brown, Paul K.; Smith, Patricia H.

1955-01-01

The iodopsin system found in the cones of the chicken retina is identical with the rhodopsin system in its carotenoids. It differs only in the protein—the opsin —with which carotenoid combines. The cone protein may be called photopsin to distinguish it from the scotopsins of the rods. Iodopsin bleaches in the light to a mixture of photopsin and all-trans retinene. The latter is reduced by alcohol dehydrogenase and cozymase to all-trans vitamin A1. Iodopsin is resynthesized from photopsin and a cis isomer of vitamin A, neovitamin Ab or the corresponding neoretinene b, the same isomer that forms rhodopsin. The synthesis of iodopsin from photopsin and neoretinene b is a spontaneous reaction. A second cis retinene, isoretinene a, forms iso-iodopsin (λmax 510 mµ). The bleaching of iodopsin in moderate light is a first-order reaction (Bliss). The synthesis of iodopsin from neoretinene b and opsin is second-order, like that of rhodopsin, but is very much more rapid. At 10°C. the velocity constant for iodopsin synthesis is 527 times that for rhodopsin synthesis. Whereas rhodopsin is reasonably stable in solution from pH 4–9, iodopsin is stable only at pH 5–7, and decays rapidly at more acid or alkaline reactions. The sulfhydryl poison, p-chloromercuribenzoate, blocks the synthesis of iodopsin, as of rhodopsin. It also bleaches iodopsin in concentrations which do not attack rhodopsin. Hydroxylamine also bleaches iodopsin, yet does not poison its synthesis. Hydroxylamine acts by competing with the opsins for retinene. It competes successfully with chicken, cattle, or frog scotopsin, and hence blocks rhodopsin synthesis; but it is less efficient than photopsin in trapping retinene, and hence does not block iodopsin synthesis. Though iodopsin has not yet been prepared in pure form, its absorption spectrum has been computed by two independent procedures. This exhibits an α-band with λmax 562 mµ, a minimum at about 435 mµ, and a small β-band in the near ultraviolet at about 370 mµ. The low concentration of iodopsin in the cones explains to a first approximation their high threshold, and hence their status as organs of daylight vision. The relatively rapid synthesis of iodopsin compared with rhodopsin parallels the relatively rapid dark adaptation of cones compared with rods. A theoretical relation is derived which links the logarithm of the visual sensitivity with the concentration of visual pigment in the rods and cones. Plotted in these terms, the course of rod and cone dark adaptation resembles closely the synthesis of rhodopsin and iodopsin in solution. The spectral sensitivities of rod and cone vision, and hence the Purkinje phenomenon, have their source in the absorption spectra of rhodopsin and iodopsin. In the chicken, for which only rough spectral sensitivity measurements are available, this relation can be demonstrated only approximately. In the pigeon the scotopic sensitivity matches the spectrum of rhodopsin; but the photopic sensitivity is displaced toward the red, largely or wholly through the filtering action of the colored oil globules in the pigeon cones. In cats, guinea pigs, snakes, and frogs, in which no such colored ocular structures intervene, the scotopic and photopic sensitivities match quantitatively the absorption spectra of rhodopsin and iodopsin. In man the scotopic sensitivity matches the absorption spectrum of rhodopsin; but the photopic sensitivity, when not distorted by the yellow pigmentations of the lens and macula lutea, lies at shorter wave lengths than iodopsin. This discrepancy is expected, for the human photopic sensitivity represents a composite of at least three classes of cone concerned with color vision. PMID:14367777

Synthesis of CeO2 nanoparticles: Photocatalytic and antibacterial activities

NASA Astrophysics Data System (ADS)

Reddy Yadav, L. S.; Lingaraju, K.; Daruka Prasad, B.; Kavitha, C.; Banuprakash, G.; Nagaraju, G.

2017-05-01

We have successfully synthesized CeO2 nanoparticles (Nps) via the solution combustion method using sugarcane juice as a novel combustible fuel. The structural features, optical properties and morphology of the nanoparticles were characterized using XRD, FTIR, and Raman spectroscopy, UV-Vis, SEM and TEM. Structural characterization of the product shows cubic phase CeO2 . FTIR and Raman spectrum show characteristic peaks due to the presence of Ce-O vibration. SEM images show a porous structure and, from TEM images, the size of the nanoparticles were found to be ˜ 50 nm. The photocatalytic degradation of the methylene blue (MB) dye was examined using CeO2 Nps under solar irradiation as well as UV light irradiation and we studied the effect of p H, catalytic load and concentration on the degradation of the MB dye. Furthermore, the antibacterial properties of CeO2 Nps were investigated against Gram+ve and Gram- ve pathogenic bacterial strains using the agar well diffusion method.

Synthesis and characterization of structural, morphological and photosensor properties of Cu0.1Zn0.9S thin film prepared by a facile chemical method

NASA Astrophysics Data System (ADS)

Gubari, Ghamdan M. M.; Ibrahim Mohammed S., M.; Huse, Nanasaheb P.; Dive, Avinash S.; Sharma, Ramphal

2018-05-01

The Cu0.1Zn0.9S thin film was grown by facile chemical bath deposition (CBD) method on glass substrates at 60°C. The structural, morphological, photosensor properties of the as-grown thin film has been investigated. The structural and phase confirmation of the as-grown thin film was carried out by X-ray diffraction (XRD) technique and Raman spectroscopy. The FE-SEM images showed that the thin films are well covered with material on an entire glass substrate. From the optical absorption spectrum, the direct band gap energy for the Cu0.1Zn0.9S thin film was found to be ˜3.16 eV at room temperature. The electrical properties were measured at room temperature in the voltage range ±2.5 V, showed a drastic enhancement in current under light illumination with the highest photosensitivity of ˜72 % for 260 W.

Controlling the size of gold nanoparticles grown on indium tin oxide substrates prepared by seed mediated growth method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fauzia, Vivi, E-mail: vivi@sci.ui.ac.id; Pratiwi, Nur Intan; Adela, Faiz

One of the unique optical properties of gold nanoparticles is the enhanced absorption and scattering light around metal nanoparticles commonly called the Localized Surface Plasmon Resonance (LSPR) effect of gold nanoparticles. This property is determined by the shape and size of gold nanoparticles. In this work, we observed the role of three materials used in synthesis process on the morphology and the LSPR effect of gold nanoparticles. The gold nanoparticles were directly grown on indium tin oxide (ITO) coated glass substrates using the seed mediated growth method with three different concentrations of trisodium citrate (Na{sub 3}C{sub 6}H{sub 5}O{sub 7}), C{submore » 16}TAB and ascorbic acid (C{sub 6}H{sub 8}O{sub 6}). Based on the FESEM image and optical absorption spectrum of gold nanoparticles, it was found that the higher concentration of those materials has decreased the size of gold nananoparticles and shifted the LSPR peaks to lower wavelength.« less

Microstructure and magnetic properties of MFe2O4 (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method

NASA Astrophysics Data System (ADS)

Wang, Wei; Ding, Zui; Zhao, Xiruo; Wu, Sizhu; Li, Feng; Yue, Ming; Liu, J. Ping

2015-05-01

Three kinds of spinel ferrite nanocrystals, MFe2O4 (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH4) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modes at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (Ms). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.

Synthesis and characterization of Y2O3 nano-material: An experimental and theoretical study

NASA Astrophysics Data System (ADS)

Ahmad, Sheeraz; Faizan, Mohd; Ahmad, Shabbir; Ikram, Mohd

2018-04-01

We made an attempt to synthesize pure Y2O3 nanomaterial by using the sol-gel method followed by annealing at 600°C and 900°C. The synthesized Y2O3 nanoparticle was characterized by using XRD, FTIR, and UV-Vis spectroscopy. The structural refinement was performed using FULLPROF software by the Rietveld method. The refinement parameters such as lattice constant, atomic position, occupancy, R-factor and goodness of fit (χ2) were calculated. The nanoparticle has a single phase cubic structure with Ia -3 space group. The main absorption band in FTIR spectra centered at 560 cm-1 is attributed to Y-O vibration while the broadband at 3450 cm-1 arises due to O-H vibration. The band gap was obtained from the reflectance spectra using the K-M function F(R∞). The optimized structural parameters and UV-Vis spectrum were calculated using DFT and TD-DFT/B3LYP methods in bulk phase of Y2O3 and compared with experimental UV-Vis spectra in nanophase.

Solution-combustion synthesis of doped TiO2 compounds and its potential antileishmanial activity mediated by photodynamic therapy.

PubMed

Lopera, A A; Velásquez, A M A; Clementino, L C; Robledo, S; Montoya, A; de Freitas, L M; Bezzon, V D N; Fontana, C R; Garcia, C; Graminha, M A S

2018-06-01

Photodynamic therapy has emerged as an alternative treatment for cutaneous leishmaniasis, and compounds with photocatalytic behavior are promising candidates to develop new therapeutic strategies for the treatment of this parasitic disease. Titanium dioxide TiO 2 is a semiconductor ceramic material that shows excellent photocatalytic and antimicrobial activity under Ultraviolet irradiation. Due to the harmful effects of UV radiation, many efforts have been made in order to enhance both photocatalytic and antimicrobial properties of TiO 2 in the visible region of the spectrum by doping or through modifications in the route of synthesis. Herein, Fe-, Zn-, or Pt- doped TiO 2 nanostructures were synthesized by solution-combustion route. The obtained compounds presented aggregates of 100 nm, formed by particles smaller than 20 nm. Doping compounds shift the absorption spectrum towards the visible region, allowing production of reactive oxygen species in the presence of oxygen and molecular water when the system is irradiated in the visible spectrum. The Pt (EC 50  = 18.2 ± 0.8 μg/mL) and Zn (EC 50  = 16.4 ± 0.3 μg/mL) -doped TiO 2 presented the higher antileishmanial activities under visible irradiation and their application as photosensitizers in photodynamic therapy (PDT) strategies for the treatment of cutaneous leishmaniasis should be considered. Copyright © 2018 Elsevier B.V. All rights reserved.

Knowledge synthesis methods for generating or refining theory: a scoping review reveals that little guidance is available.

PubMed

Tricco, Andrea C; Antony, Jesmin; Soobiah, Charlene; Kastner, Monika; Cogo, Elise; MacDonald, Heather; D'Souza, Jennifer; Hui, Wing; Straus, Sharon E

2016-05-01

To describe and compare, through a scoping review, emerging knowledge synthesis methods for generating and refining theory, in terms of expertise required, similarities, differences, strengths, limitations, and steps involved in using the methods. Electronic databases (e.g., MEDLINE) were searched, and two reviewers independently selected studies and abstracted data for qualitative analysis. In total, 287 articles reporting nine knowledge synthesis methods (concept synthesis, critical interpretive synthesis, integrative review, meta-ethnography, meta-interpretation, meta-study, meta-synthesis, narrative synthesis, and realist review) were included after screening of 17,962 citations and 1,010 full-text articles. Strengths of the methods included comprehensive synthesis providing rich contextual data and suitability for identifying gaps in the literature, informing policy, aiding in clinical decisions, addressing complex research questions, and synthesizing patient preferences, beliefs, and values. However, many of the methods were highly subjective and not reproducible. For integrative review, meta-ethnography, and realist review, guidance was provided on all steps of the review process, whereas meta-synthesis had guidance on the fewest number of steps. Guidance for conducting the steps was often vague and sometimes absent. Further work is needed to provide direction on operationalizing these methods. Copyright © 2016 Elsevier Inc. All rights reserved.

Green urea synthesis catalyzed by hematite nanowires in magnetic field

NASA Astrophysics Data System (ADS)

Yahya, Noorhana; Qureshi, Saima; Rehman, Zia ur; Alqasem, Bilal; Fai Kait, Chong

2017-04-01

The catalytic activity of hematite (α-Fe2O3) nanowires under the influence of magnetic field on urea synthesis is considered green. The adsorption and subsequent dissociative reaction of hydrogen, nitrogen and carbon dioxide gases on the α-Fe2O3 (111) nanowires were investigated using the density functional theory (DFT) method. The average adsorption energy is -4.12 kcal/mole at different sites. The adsorption of gases resulted in a difference in density and net spin of electrons from 68 to 120 and 0-21 respectively. In addition, it induces magnetic moment value of 36.33 μB, which confirms the enhanced magnetic behaviour of hematite. α-Fe2O3 nanowires (NWs) synthesized by heating iron wire in a box furnace at (750-800) °C and as synthesized α-Fe2O3 nanoparticles (NPs) were received to use as a catalyst in the magnetic reaction of urea synthesis. X-ray Diffractometer (XRD) confirms the peaks of rhombohedral structure of α-Fe2O3 and Raman spectrum analyses confirms the α-Fe2O3 peaks at 410 cm-1, 500 cm-1 and 616 cm-1. The needle-like shape of hematite nanowires with length ranging from 16-25) μm and diameter from 74 to 145 nm confirmed by Field emission scanning electron microscopy (FESEM). The magnetic properties of the nanowires exhibited different levels of saturation magnetization, for α-Fe2O3 perpendicularly aligned direction (13.18 emu/g) and random direction (10.73 emu/g). Urea synthesis was done under magnetic field ranges from 0.0 to 2.5 T. The activation energy of α-Fe2O3 NWs for urea production is lower than NPs in the range of 0-1 T, whereas it is reversed for higher magnetic induction values. Fourier transform infrared spectroscopy (FTIR) confirmed the formation of urea at the peaks of 1690-1600 cm-1. This green urea employing magnetically induced method could be a contender to the Haber-Bosch process currently used by the current industry which utilizes high temperature and high pressure.

Creating wavelet-based models for real-time synthesis of perceptually convincing environmental sounds

NASA Astrophysics Data System (ADS)

Miner, Nadine Elizabeth

1998-09-01

This dissertation presents a new wavelet-based method for synthesizing perceptually convincing, dynamic sounds using parameterized sound models. The sound synthesis method is applicable to a variety of applications including Virtual Reality (VR), multi-media, entertainment, and the World Wide Web (WWW). A unique contribution of this research is the modeling of the stochastic, or non-pitched, sound components. This stochastic-based modeling approach leads to perceptually compelling sound synthesis. Two preliminary studies conducted provide data on multi-sensory interaction and audio-visual synchronization timing. These results contributed to the design of the new sound synthesis method. The method uses a four-phase development process, including analysis, parameterization, synthesis and validation, to create the wavelet-based sound models. A patent is pending for this dynamic sound synthesis method, which provides perceptually-realistic, real-time sound generation. This dissertation also presents a battery of perceptual experiments developed to verify the sound synthesis results. These experiments are applicable for validation of any sound synthesis technique.

Melatonin in children with autistic spectrum disorders: recent and practical data.

PubMed

Doyen, C; Mighiu, D; Kaye, K; Colineaux, C; Beaumanoir, C; Mouraeff, Y; Rieu, C; Paubel, P; Contejean, Y

2011-05-01

Over the last 20 years, melatonin, a pineal hormone synthesized from serotonin, has been implicated in various studies on the autism spectrum disorder (ASD) and altered melatonin levels were detected in subgroups of subjects with ASD. Its effect on sleep disturbances got the attention of clinicians and several investigations were carried out to determine the usefulness and safety of melatonin administration in this disorder. Hypotheses were also raised regarding the possibility that the dysfunctional synthesis and secretion of melatonin detected in subgroups of subjects with ASD may increase the risk as well the severity of ASD. The purpose of this paper is to review our pharmacokinetic knowledge on melatonin and present results from recent studies on sleep disorders in autism, their treatment with melatonin and the impact of melatonin prescription in children with ASD evaluated in a Diagnostic Center for Autism Spectrum Disorder in Paris, France.

Synthesis and spectroscopic study of CdS nanoparticles using hydrothermal method

NASA Astrophysics Data System (ADS)

AL-Mamoori, Mohammed H. K.; Mahdi, Dunia K.; Al-Shrefi, Saif M.

2018-05-01

In this work, cadmium sulfide nanoparticles (powder) with diameter 50.8 nm was prepared using hydrothermal method. The structural and optical properties of CdS nanoparticles was studied by X-ray diffraction, FESEM, EDS, FTIR, UV-Diffuse Reflectance spectroscopy and Photoluminance spectrum. X-ray diffraction reveal the formation the purity of prepared phase of CdS particles with hexagonal wurtzite structure with particle size 31.8nm by using sheerer equation. The energy dispersion scattering (EDS) examination explains that the sample is composed of a large amount of Cd and S which are exactly CdS nanoparticles and there is a very small trace of (Zn) and (O) element observed because of there is a small pollutions in the measurement place of samples. FESEM shows the spherical shape of nanoparticles with around 50.8 nm diameter. The optical absorption spectral study identified the red shift of the sample in comparison to bulk ZnO in three dimensions. Photoluminance spectrum (PL) at room temperature showed that there are two luminescence peaks at 433.14 nm and 518.21nm. Samples demonstrate a sharp emission band at around 433.18 nm, which is attributed to the typical exciton luminescence. The broad band at 518.21nm which were attributed to the trapped luminescence. The green emission band at 518.21 nm was associated with the emission due to electronic transition from the conduction band to an accepter level due to interstitial sulphur ion.

“Best fit” framework synthesis: refining the method

PubMed Central

2013-01-01

Background Following publication of the first worked example of the “best fit” method of evidence synthesis for the systematic review of qualitative evidence in this journal, the originators of the method identified a need to specify more fully some aspects of this particular derivative of framework synthesis. Methods and Results We therefore present a second such worked example in which all techniques are defined and explained, and their appropriateness is assessed. Specified features of the method include the development of new techniques to identify theories in a systematic manner; the creation of an a priori framework for the synthesis; and the “testing” of the synthesis. An innovative combination of existing methods of quality assessment, analysis and synthesis is used to complete the process. This second worked example was a qualitative evidence synthesis of employees’ views of workplace smoking cessation interventions, in which the “best fit” method was found to be practical and fit for purpose. Conclusions The method is suited to producing context-specific conceptual models for describing or explaining the decision-making and health behaviours of patients and other groups. It offers a pragmatic means of conducting rapid qualitative evidence synthesis and generating programme theories relating to intervention effectiveness, which might be of relevance both to researchers and policy-makers. PMID:23497061

Nanosilver - does it have only one face?

PubMed

Likus, Wirginia; Bajor, Grzegorz; Siemianowicz, Krzysztof

2013-01-01

Silver nanoparticles (NPs) have at least one dimension of a particle smaller than 100 nm and contain 20-15,000 silver atoms. Due to its antibacterial activity nanosilver (NS) is used for medical purposes. NS particles can be obtained by various methods. Potentially, the best method of the NS synthesis for medical purposes is based on a brief flow of electric current between two silver electrodes placed in deionized water. It is accepted that the major antibacterial effect of silver is its partial oxidation and releasing silver ions, which interact with thiol groups of peptidoglicans of bacterial cell wall, and proteins of the cell membrane causing cell lysis. Silver ions can also bind to bacterial DNA preventing its replication and stopping synthesis of bacterial proteins. The rise in exposure to silver NPs has spurred interest into their toxicology. NS undergoes a set of biochemical transformations including accelerated oxidative dissolution in gastric acid, binding to thiol groups of serum and tissue proteins, exchange between thiol groups, sulfides and selenides, binding to selenoproroteins and photoreduction in skin to zerovalent metallic silver. Animal studies have shown that exposure to NS may lead to liver and spleen damage. NS can also stimulate an increased secretion of proinflammatory cytokines by monocytes. As a spectrum of NS applications is still growing, the complex evaluation of a safety of its use becomes an important task. This requires an elucidation of not only the influence of NS on human cells and organism, but also its biotransformation in organism and in environment.

Spatial layout optimization design of multi-type LEDs lighting source based on photoelectrothermal coupling theory

NASA Astrophysics Data System (ADS)

Xue, Lingyun; Li, Guang; Chen, Qingguang; Rao, Huanle; Xu, Ping

2018-03-01

Multiple LED-based spectral synthesis technology has been widely used in the fields of solar simulator, color mixing, and artificial lighting of plant factory and so on. Generally, amounts of LEDs are spatially arranged with compact layout to obtain the high power density output. Mutual thermal spreading among LEDs will produce the coupled thermal effect which will additionally increase the junction temperature of LED. Affected by the Photoelectric thermal coupling effect of LED, the spectrum of LED will shift and luminous efficiency will decrease. Correspondingly, the spectral synthesis result will mismatch. Therefore, thermal management of LED spatial layout plays an important role for multi-LEDs light source system. In the paper, the thermal dissipation network topology model considering the mutual thermal spreading effect among the LEDs is proposed for multi-LEDs system with various types of power. The junction temperature increment cased by the thermal coupling has the great relation with the spatial arrangement. To minimize the thermal coupling effect, an optimized method of LED spatial layout for the specific light source structure is presented and analyzed. The results showed that layout of LED with high-power are arranged in the corner and low-power in the center. Finally, according to this method, it is convenient to determine the spatial layout of LEDs in a system having any kind of light source structure, and has the advantages of being universally applicable to facilitate adjustment.

An Ingenious Super Light Trapping Surface Templated from Butterfly Wing Scales

NASA Astrophysics Data System (ADS)

Han, Zhiwu; Li, Bo; Mu, Zhengzhi; Yang, Meng; Niu, Shichao; Zhang, Junqiu; Ren, Luquan

2015-08-01

Based on the super light trapping property of butterfly Trogonoptera brookiana wings, the SiO2 replica of this bionic functional surface was successfully synthesized using a simple and highly effective synthesis method combining a sol-gel process and subsequent selective etching. Firstly, the reflectivity of butterfly wing scales was carefully examined. It was found that the whole reflectance spectroscopy of the butterfly wings showed a lower level (less than 10 %) in the visible spectrum. Thus, it was confirmed that the butterfly wings possessed a super light trapping effect. Afterwards, the morphologies and detailed architectures of the butterfly wing scales were carefully investigated using the ultra-depth three-dimensional (3D) microscope and field emission scanning electronic microscopy (FESEM). It was composed by the parallel ridges and quasi-honeycomb-like structure between them. Based on the biological properties and function above, an exact SiO2 negative replica was fabricated through a synthesis method combining a sol-gel process and subsequent selective etching. At last, the comparative analysis of morphology feature size and the reflectance spectroscopy between the SiO2 negative replica and the flat plate was conducted. It could be concluded that the SiO2 negative replica inherited not only the original super light trapping architectures, but also the super light trapping characteristics of bio-template. This work may open up an avenue for the design and fabrication of super light trapping materials and encourage people to look for more super light trapping architectures in nature.

Biosynthesis of Stable Antioxidant ZnO Nanoparticles by Pseudomonas aeruginosa Rhamnolipids

PubMed Central

Singh, Brahma Nand; Rawat, Ajay Kumar Singh; Khan, Wasi; Naqvi, Alim H.; Singh, Braj Raj

2014-01-01

During the last several years, various chemical methods have been used for synthesis of a variety of metal nanoparticles. Most of these methods pose severe environmental problems and biological risks; therefore the present study reports a biological route for synthesis of zinc oxide nanoparticles using Pseudomonas aeruginosa rhamnolipids (RLs) (denoted as RL@ZnO) and their antioxidant property. Formation of stable RL@ZnO nanoparticles gave mostly spherical particles with a particle size ranging from 35 to 80 nm. The RL@ZnO nanoparticles were characterized by UV-visible (UV–vis) spectroscopy, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction (XRD), and thermal gravimetric analysis. The UV–vis spectra presented a characteristic absorbance peak at ∼360 nm for synthesized RL@ZnO nanoparticles. The XRD spectrum showed that RL@ZnO nanoparticles are crystalline in nature and have typical wurtzite type polycrystals. Antioxidant potential of RL@ZnO nanoparticles was assessed through 2,2–diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion free radicals with varying concentration and time of the storage up to 15 months, while it was found to decline in bare ZnO nanoparticles. Similarly, the inhibitory effects on β-carotene oxidation and lipid peroxidation were also observed. These results elucidate the significance of P. aeruginosa RL as effective stabilizing agents to develop surface protective ZnO nanoparticles, which can be used as promising antioxidants in biological system. PMID:25187953

Room-Temperature Synthesis of GaN Driven by Kinetic Energy beyond the Limit of Thermodynamics.

PubMed

Imaoka, Takane; Okada, Takeru; Samukawa, Seiji; Yamamoto, Kimihisa

2017-12-06

The nitridation reaction is significantly important to utilize the unique properties of nitrides and nitrogen-doped materials. However, nitridation generally requires a high temperature or highly reactive reagents (often explosive) because the energies of N-N bond cleavage and nitrogen anion formation (N 3- ) are very high. We demonstrate the first room-temperature synthesis of GaN directly from GaCl 3 by nanoscale atom exchange reaction. Nonequilibrium nitrogen molecules with very high translational energy were used as a chemically stable and safe nitrogen source. The irradiation of molecular nitrogen to the desired reaction area successfully provided a gallium nitride (GaN) nanosheet that exhibited a typical photoluminescence spectrum. Because this process retains the target substrate room temperature and does not involve any photon nor charged ion, it allows damage-less synthesis of the semiconducting metal nitrides, even directly on plastic substrates such as polyethylene terephthalate (PET).

Efficient tungsten oxide/bismuth oxyiodide core/shell photoanode for photoelectrochemical water splitting

NASA Astrophysics Data System (ADS)

Ma, Haipeng; Zhang, Jing; Liu, Zhifeng

2017-11-01

The novel WO3 nanorods (NRs)/BiOI core/shell structure composite is used as an efficient photoanode applied in photoelectrochemical (PEC) water splitting for the first time. It is synthesized via facile hydrothermal method and, successive ionic layer adsorption and reaction (SILAR) process. This facile synthesis route can achieve uniform WO3/BiOI core/shell composite nanostructures and obtain varied BiOI morphologies simultaneously. The WO3 NRs/BiOI-20 composite exhibits enhanced PEC activity compared to pristine WO3 with a photocurrent density of 0.79 mA cm-2 measured at 0.8 V vs. RHE under AM 1.5G. This excellent performance benefits from the broader absorption spectrum and suppressed electron-hole recombination. This novel core/shell composite may provide insight in developing more efficient solar driven photoelectrodes.

Synthesis and structural characterization of Co2+ ions doped ZnO nanopowders by solid state reaction through sonication

NASA Astrophysics Data System (ADS)

Babu, B.; Rama Krishna, Ch.; Venkata Reddy, Ch.; Pushpa Manjari, V.; Ravikumar, R. V. S. S. N.

2013-05-01

Cobalt ions doped zinc oxide nanopowder was prepared at room temperature by a novel and simple one step solid-state reaction method through sonication in the presence of a suitable surfactant Sodium Lauryl Sulphate (SLS). The prepared powder was characterized by various spectroscopic techniques. Powder XRD data revealed that the crystal structure belongs to hexagonal and its average crystallite size was evaluated. From optical absorption data, crystal fields (Dq), inter-electronic repulsion parameters (B, C) were evaluated. By correlating optical and EPR spectral data, the site symmetry of Co2+ ion in the host lattice was determined as octahedral. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions. The CIE chromaticity coordinates are also evaluated from the emission spectrum. FT-IR spectra showed the characteristic vibrational bands of Znsbnd O.

Synthesis and characterization of α-cobalt hydroxide nanobelts

NASA Astrophysics Data System (ADS)

Tian, L.; Zhu, J. L.; Chen, L.; An, B.; Liu, Q. Q.; Huang, K. L.

2011-08-01

α-Cobalt hydroxide was synthesized by a facile hydrothermal process from Co(Ac)2 and NH3·H2O in the presence of 1,3-propanediol. The large-scale-prepared cobalt hydroxide has a uniform nanobelt morphology with a considerably high aspect-ratio more than 20 which may be advantageous for exploration of their physicochemical properties. This synthetic method is convenient, economical, and controllable. The samples were characterized by powder X-ray diffraction, energy dispersive spectrum, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, CHN element analysis, thermogravimetric and differential-thermogravimetric analysis, which revealed the compound is lamellar structural cobalt organic-inorganic hybrid with the chemical formula of Co(OH)1.49(NH3)0.01(CO3 2-)0.22(Ac-)0.07(H2O)0.11 and single-crystalline.

Chemical Characteristics, Synthetic Methods, and Biological Potential of Quinazoline and Quinazolinone Derivatives

PubMed Central

2014-01-01

The heterocyclic fused rings quinazoline and quinazolinone have drawn a huge consideration owing to their expanded applications in the field of pharmaceutical chemistry. Quinazoline and quinazolinone are reported for their diversified biological activities and compounds with different substitutions bring together to knowledge of a target with understanding of the molecule types that might interact with the target receptors. Quinazolines and quinazolinones are considered as an important chemical for the synthesis of various physiological significance and pharmacological utilized molecules. Quinazolines and quinazolinone are a large class of biologically active compounds that exhibited broad spectrum of biological activities such as anti-HIV, anticancer, antifungal, antibacterial, antimutagenic, anticoccidial, anticonvulsant, anti-inflammatory, antidepressant, antimalarial, antioxidant, antileukemic, and antileishmanial activities and other activities. Being considered as advantaged scaffold, the alteration is made with different substituent. PMID:25692041

A simple, convenient method to synthesize cobalamins: synthesis of homocysteinylcobalamin, N -acetylcysteinylcobalamin, 2-N -acetylamino-2-carbomethoxyethanethiolatocobalamin, sulfitocobalamin and nitrocobalamin†

PubMed Central

Suarez-Moreira, Edward; Hannibal, Luciana; Smith, Clyde A.; Chavez, Roberto A.; Jacobsen, Donald W.

2009-01-01

Glutathionylcobalamin, nitrocobalamin and sulfitocobalamin are important cobalamin metabolites isolable from human tissues. Herein we demonstrate that a procedure used to synthesize and isolate γ-glutamylcysteinylcobalamin and glutathionylcobalamin in aqueous solution in high yield and purity can be used to synthesize other novel, biologically relevant thiolatocobalamins, including D,L-homocysteinylcobalamin, N-acetyl-L-cysteinylcobalamin (Na+ salt) and 2-N-acetylamino-2-carbomethoxy-L-ethanethiolatocobalamin, as well as other non-alkylcobalamins, such as sulfitocobalamin (Na+ salt) and nitrocobalamin. This uncomplicated, general procedure will assist researchers in identifying unknown cobalamin metabolites isolated from biological samples, and researchers interested in studying the uptake and intracellular cobalamin processing mechanisms utilizing non-alkylcobalamin derivatives that are not yet commercially available. The X-ray structure and XAS spectrum of N-acetyl-L-cysteinylcobalamin are also presented. PMID:17088966

Two-fold interpenetrating btc based cobaltous coordination polymer: A promising catalyst for solvent free oxidation of 1-hexene

NASA Astrophysics Data System (ADS)

Bora, Sanchay J.; Paul, Rima; Nandi, Mithun; Bhattacharyya, Pradip K.

2017-12-01

This work describes the synthesis of a new 2-D coordination polymer (CP), [Co3(btc)2(dmp)8]n (btc = 1,3,5-benzenetricarboxylate and dmp = 3,5-dimethylpyrazole) and its catalytic activity towards the oxidation reaction of 1-hexene to form oxygenated compounds under solvent free condition. Structural analysis reveals that Co(II) cations in this polymeric compound are linked by btc3- anions with alternate tetrahedral/octahedral coordination forming a two-fold interpenetrated 3-connected hcb underlying net. Electronic spectrum of the cobaltous polymer has been calculated using TDDFT/B3LYP method for making the appropriate assignments of electronic transitions. Catalytic results show good conversions of the starting material to oxygenated products with high selectivities for 1,2-epoxyhexane and 1-hexanal.

Synthesis, structural, magnetic and optical properties of Sr2CoSn based inverse Heusler alloy nanoparticles

NASA Astrophysics Data System (ADS)

Asvini, V.; Saravanan, G.; Kalaiezhily, R. K.; Ravichandran, K.

2018-05-01

The peculiar ternary full Heusler alloy Sr2CoSn nanoparticles are synthesized by co-precipitation method. X- ray diffraction pattern confirms the formation of XA or Xα structure of Sr2CoSn. Using Williamson-Hall plot (W-H plot), we are able to use the uniform deformation model and get low value of strain induced broadening. UV-Visible absorption spectrum shows sharp absorption peak at 210 nm and the estimated band gap energy of Sr2CoSn Heusler alloy nanoparticles is Eg = 4.6 eV (from Tauc plot). The presence of Sr2CoSn with the particle size of approximately 90 nm was observed using high resolution scanning electron microscopy. The magnetization measurements were carried out using VSM and studied M verses H hysteresis studies.

Development of a one-step gene knock-out and knock-in method for metabolic engineering of Aureobasidium pullulans.

PubMed

Guo, Jian; Wang, Yuanhua; Li, Baozhong; Huang, Siyao; Chen, Yefu; Guo, Xuewu; Xiao, Dongguang

2017-06-10

Aureobasidium pullulans is an increasingly attractive host for bio-production of pullulan, heavy oil, polymalic acid, and a large spectrum of extracellular enzymes. To date, genetic manipulation of A. pullulans mainly relies on time-consuming conventional restriction enzyme digestion and ligation methods. In this study, we present a one-step homologous recombination-based method for rapid genetic manipulation in A. pullulans. Overlaps measuring >40bp length and 10μg DNA segments for homologous recombination provided maximum benefits to transformation of A. pullulans. This optimized method was successfully applied to PKSIII gene (encodes polyketide synthase) knock-out and gltP gene (encodes glycolipid transfer protein) knock-in. After disruption of PKSIII gene, secretion of melanin decreased slightly. The melanin purified from disruptant showed lower reducing capacity compared with that of the parent strain, leading to a decrease in exopolysaccharide production. Knock-in of gltP gene resulted in at least 4.68-fold increase in heavy oil production depending on the carbon source used, indicating that gltP can regulate heavy oil synthesis in A. pullulans. Copyright © 2017 Elsevier B.V. All rights reserved.

Synthesis and characterization of nanoparticles conjugated tannase and using it for enhancement of antibacterial activity of tannase produced by Serratia marcescens.

PubMed

Nsayef Muslim, D Sahira; Abbas Dham, Ziyad; J Mohammed, D Nadheer

2017-09-01

Fourteen isolates of Serratia marcescens were collected from patients suffering from septicemia. All theseisolates revealed different levels in tannase production. Tannase was partially purified from Serratia marcescens b9 by precipitation method at 70% saturation of ammonium sulfate. Au, Pt, SnO 2 and SiO 2 nanoparticles were prepared by laser ablation and examined by transmission electron microscopy (TEM), X-ray diffraction pattern and UV-Visible absorption spectroscopy. Conjugation of SiO 2 nanoparticles to tannase by feeding and pulses methods were prepared and characterized by TEM, X-ray diffraction pattern and UV-Visible spectrum. SiO 2 nanoparticles conjugated partially purified tannase by feeding showed the higher effectiveness and higher significant level against all tested UTI causing in comparison with ciprofloxacin antibiotic, SiO 2 nanoparticles alone, partially purified tannase alone and partially purified tannase by pulses. So that we can conclude that feeding method was the best method for enhancement partially purified tannase activity to maximum level thus SiO 2 nanoparticles conjugated partially purified tannase may be a useful antibacterial agent for the treatment of urinary tract infection. Copyright © 2017 Elsevier Ltd. All rights reserved.

Synthesis, optical and electrochemical properties of Zn-porphyrin for dye sensitized solar cell applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kotteswaran, S.; Pandian, M. Senthil; Ramasamy, P., E-mail: ramasamyp@ssn.edu.in

2016-05-23

Zn-Porphyrin dye has been synthesized by the reaction between aldehydes and pyrrole. The dye structure was confirmed by {sup 1}H NMR, {sup 13}C NMR spectrum. The functional group of the dye molecule was confirmed by FTIR spectrum. The UV-Vis-NIR absorption spectrum of Zn-Porphyrin in DMF solution was recorded in spectrophotometer. The UV-Vis NIR spectrum of dye exhibits a strong Soret band and Q-band. Cyclic Voltammograms were obtained with three electrode systems: Pt as counter electrode, saturated calomel used as a reference electrode and glassy carbon as working electrode at a scan rate of 100 mV/s. The curves recorded the oxidation ofmore » 0.5 mM compound Zn-Porphyrin in a dichloromethane solution containing 0.1M TBAP as supporting electrolyte, reveal two successive quasi reversible redox couples with the first anodic and cathodic peak potentials of -0.2 V and -1 V. The second anodic and cathodic peak potentials are 0.82 V and 0.01 V respectively.« less

Synthesis of dynamic phase profile by the correlation technique for spatial control of optical beams in multiplexing and switching

NASA Astrophysics Data System (ADS)

Bugaychuk, Svitlana A.; Gnatovskyy, Vladimir O.; Sidorenko, Andrey V.; Pryadko, Igor I.; Negriyko, Anatoliy M.

2015-11-01

New approach for the correlation technique, which is based on multiple periodic structures to create a controllable angular spectrum, is proposed and investigated both theoretically and experimentally. The transformation of an initial laser beam occurs due to the actions of consecutive phase periodic structures, which may differ by their parameters. Then, after the Fourier transformation of a complex diffraction field, the output diffraction orders will be changed both by their intensities and by their spatial position. The controllable change of output angular spectrum is carried out by a simple control of the parameters of the periodic structures. We investigate several simple examples of such management.

Digital Sound Synthesis Algorithms: a Tutorial Introduction and Comparison of Methods

NASA Astrophysics Data System (ADS)

Lee, J. Robert

The objectives of the dissertation are to provide both a compendium of sound-synthesis methods with detailed descriptions and sound examples, as well as a comparison of the relative merits of each method based on ease of use, observed sound quality, execution time, and data storage requirements. The methods are classified under the general headings of wavetable-lookup synthesis, additive synthesis, subtractive synthesis, nonlinear methods, and physical modelling. The nonlinear methods comprise a large group that ranges from the well-known frequency-modulation synthesis to waveshaping. The final category explores computer modelling of real musical instruments and includes numerical and analytical solutions to the classical wave equation of motion, along with some of the more sophisticated time -domain models that are possible through the prudent combination of simpler synthesis techniques. The dissertation is intended to be understandable by a musician who is mathematically literate but who does not necessarily have a background in digital signal processing. With this limitation in mind, a brief and somewhat intuitive description of digital sampling theory is provided in the introduction. Other topics such as filter theory are discussed as the need arises. By employing each of the synthesis methods to produce the same type of sound, interesting comparisons can be made. For example, a struck string sound, such as that typical of a piano, can be produced by algorithms in each of the synthesis classifications. Many sounds, however, are peculiar to a single algorithm and must be examined independently. Psychoacoustic studies were conducted as an aid in the comparison of the sound quality of several implementations of the synthesis algorithms. Other psychoacoustic experiments were conducted to supplement the established notions of which timbral issues are important in the re -synthesis of the sounds of acoustic musical instruments.

Diesel production from Fischer-Tropsch: the past, the present, and new concepts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dieter Leckel

2009-05-15

Fischer-Tropsch synthesis is technically classified into two categories, the high-temperature Fischer-Tropsch (HTFT) and the low-temperature Fischer-Tropsch (LTFT) processes. The criterion for this classification is the operating temperature of the synthesis, which ranges between 310-340{sup o}C for the HTFT process and 210-260{sup o}C for the LTFT process. A Fischer-Tropsch facility can be divided into roughly three sections, synthesis gas (syngas) generation, FT synthesis, and refining of the synthetic crude (syncrude). Fischer-Tropsch refineries differ regarding the product upgrading, and both transportation fuels and chemicals can be produced. Regarding the FT refinery history, the configuration of each refinery also reflects the requirements ofmore » the fuel specification at that time. This paper gives a condensed overview of how Fischer-Tropsch facilities changed during the last 70 years and focuses in particular on the diesel fuel produced. Some conceptual flow schemes are additionally presented with emphasis on the combined upgrading of the high boiling part of the FT product spectrum with liquids derived from coal pyrolysis. 52 refs., 14 figs., 12 tabs.« less

Synthesis of stereospecifically deuterated desoxypodophyllotoxins and 1H-nmr assignment of desoxypodophyllotoxin

NASA Technical Reports Server (NTRS)

Pullockaran, A. J.; Kingston, D. G.; Lewis, N. G.

1989-01-01

[4 beta- 2H1]Desoxypodophyllotoxin [3], [4 alpha- 2H1]desoxypodophyllotoxin [4], and [4, 4- 2 H2]desoxypodophyllotoxin [9] were prepared from podophyllotoxin [1] via its chloride [5]. A complete assignment of the 1H-nmr spectrum of desoxypodophyllotoxin [2] was made on the basis of the spectra of the deuterated compounds [3] and [4].

Phenazines in the environment: microbes, habitats, and ecological relevance. In: Chincholkar, S., Thomashow, L., editors. Microbial phenazines: biosynthesis, agriculture and health. New York, NY; Springer

USDA-ARS?s Scientific Manuscript database

Phenazines, the pigmented, redox-active metabolites produced by certain fluorescent pseudomonads, streptomycetes, and members of a few other bacterial genera, have long been recognized for their broad-spectrum antibiotic activity. Much has been learned in recent years about the synthesis of these co...

Aero-space plane figures of merit

NASA Technical Reports Server (NTRS)

Hunt, James L.; Martin, John G.

1992-01-01

The design environment of the aerospace plane is variable rich, intricately networked and sensitivity intensive. To achieve a viable design necessitates addressing three principal elements: knowledge of the 'figures of merit' and their relationships, the synthesis procedure, and the synergistic integration of advanced technologies across the discipline spectrum. This paper focuses on the 'figures of merit' that create the design of an aerospace plane.

Synaptic Synthesis, Dephosphorylation, and Degradation

PubMed Central

La Montanara, Paolo; Rusconi, Laura; Locarno, Albina; Forti, Lia; Barbiero, Isabella; Tramarin, Marco; Chandola, Chetan; Kilstrup-Nielsen, Charlotte; Landsberger, Nicoletta

2015-01-01

Mutations in the X-linked CDKL5 (cyclin-dependent kinase-like 5) gene have been associated with several forms of neurodevelopmental disorders, including atypical Rett syndrome, autism spectrum disorders, and early infantile epileptic encephalopathy. Accordingly, loss of CDKL5 in mice results in autistic-like features and impaired neuronal communication. Although the biological functions of CDKL5 remain largely unknown, recent pieces of evidence suggest that CDKL5 is involved in neuronal plasticity. Herein, we show that, at all stages of development, neuronal depolarization induces a rapid increase in CDKL5 levels, mostly mediated by extrasomatic synthesis. In young neurons, this induction is prolonged, whereas in more mature neurons, NMDA receptor stimulation induces a protein phosphatase 1-dependent dephosphorylation of CDKL5 that is mandatory for its proteasome-dependent degradation. As a corollary, neuronal activity leads to a prolonged induction of CDKL5 levels in immature neurons but to a short lasting increase of the kinase in mature neurons. Recent results demonstrate that many genes associated with autism spectrum disorders are crucial components of the activity-dependent signaling networks regulating the composition, shape, and strength of the synapse. Thus, we speculate that CDKL5 deficiency disrupts activity-dependent signaling and the consequent synapse development, maturation, and refinement. PMID:25555910

Synthesis, microwave spectrum, and dipole moment of allenylisocyanide (H2C═C═CHNC), a compound of potential astrochemical interest.

PubMed

Møllendal, Harald; Samdal, Svein; Matrane, Abdellatif; Guillemin, Jean-Claude

2011-07-14

An improved synthesis of a compound of potential astrochemical interest, allenylisocyanide (H(2)C═C═CHNC), is reported together with its microwave spectrum, which has been investigated in the 8-120 GHz spectral range to facilitate a potential identification in interstellar space. The spectra of the ground vibrational state and of five vibrationally excited states belonging to three different vibrational modes have been assigned for the parent species. A total of 658 transitions with a maximum value of J = 71 were assigned for the ground state and accurate values obtained for the rotational and quartic centrifugal distortion constants. The spectra of five heavy-atom ((13)C and (15)N) isotopologues were also assigned. The dipole moment was determined to be μ(a) = 11.93(16) × 10(-30) C m, μ(b) = 4.393(44) × 10(-30) C m, and μ(tot) = 12.71(16) × 10(-30) C m. The spectroscopic work has been augmented by theoretical calculations at the CCSD/cc-pVTZ and B3LYP/cc-pVTZ levels of theory. The theoretical calculations are generally in good agreement with the experimental results.

Synthesis and characterization of magnesium aluminate (MgAl2O4) spinel (MAS) thin films

NASA Astrophysics Data System (ADS)

Ahmad, Syed Muhammad; Hussain, Tousif; Ahmad, Riaz; Siddiqui, Jamil; Ali, Dilawar

2018-01-01

In a quest to identify more economic routes for synthesis of magnesium aluminate (MgAl2O4) spinel (MAS) thin films, dense plasma focus device was used with multiple plasma focus shots. Structural, bonding between composite films, surface morphological, compositional and hardness properties of MAS thin films were investigated by using x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive x-rays (EDX) analysis and Vickers micro hardness test respectively. In XRD graph, the presence of MgAl2O4 diffraction peaks in crystallographic orientations (222), (400) and (622) pointed out the successful formation of polycrystalline thin films of MgAl2O4 with face centered cubic structure. The FTIR spectrums showed a major common transmittance band at 697.95 cm-1 which belongs to MgAl2O4. SEM micrographs illustrated a mesh type, granular and multi layers microstructures with significant melting effects. EDX spectrum confirmed the existence of magnesium, oxygen and aluminum in MAS films. A common increasing behavior in micro-hardness of composite MgAl2O4 films by increasing number of plasma focus shots was found.

Benign Synthesis of Black Microspheres of Anatase TiO2 with Paramagnetic Oxygen Vacancies through NH3 Treatment.

PubMed

Maqbool, Qysar; Srivastava, Aasheesh

2017-10-09

Coloured TiO 2 is coveted for its ability to extract energy from the visible region of electromagnetic spectrum. Here a facile synthesis of black anatase titania microspheres (B-TiO 2 ) through a two-step process is reported. In the first step, amorphous white TiO 2 microspheres (W-TiO 2 ) are obtained by hydrolysing titanium tetraisopropoxide by ammonia vapours in ethanol. In the second step, the W-TiO 2 is thermally annealed at 500 °C to obtain B-TiO 2 . The diffuse reflectance analysis showed that B-TiO 2 absorbs across visible spectrum with absorption extending well into NIR region. Raman scattering together with EPR analysis showed compelling evidence of the existence of oxygen deficiency within the crystal in B-TiO 2 that induces black colouration in the sample. The defects present in the black anatase sample were confirmed to be single-electron-trapped (or paramagnetic) oxygen vacancies (V o ⋅) by XPS and EPR studies. The magnetic susceptibility studies showed existence of antiferromagnetic interactions between these unpaired electron spins. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Semiconductor Seeded Nanorods with Graded Composition Exhibiting High Quantum-Yield, High Polarization, and Minimal Blinking.

PubMed

Hadar, Ido; Philbin, John P; Panfil, Yossef E; Neyshtadt, Shany; Lieberman, Itai; Eshet, Hagai; Lazar, Sorin; Rabani, Eran; Banin, Uri

2017-04-12

Seeded semiconductor nanorods represent a unique family of quantum confined materials that manifest characteristics of mixed dimensionality. They show polarized emission with high quantum yield and fluorescence switching under an electric field, features that are desirable for use in display technologies and other optical applications. So far, their robust synthesis has been limited mainly to CdSe/CdS heterostructures, thereby constraining the spectral tunability to the red region of the visible spectrum. Herein we present a novel synthesis of CdSe/Cd 1-x Zn x S seeded nanorods with a radially graded composition that show bright and highly polarized green emission with minimal intermittency, as confirmed by ensemble and single nanorods optical measurements. Atomistic pseudopotential simulations elucidate the importance of the Zn atoms within the nanorod structure, in particular the effect of the graded composition. Thus, the controlled addition of Zn influences and improves the nanorods' optoelectronic performance by providing an additional handle to manipulate the degree confinement beyond the common size control approach. These nanorods may be utilized in applications that require the generation of a full, rich spectrum such as energy-efficient displays and lighting.

Diverted Total Synthesis of Promysalin Analogs Demonstrates That an Iron-Binding Motif Is Responsible for Its Narrow-Spectrum Antibacterial Activity.

PubMed

Steele, Andrew D; Keohane, Colleen E; Knouse, Kyle W; Rossiter, Sean E; Williams, Sierra J; Wuest, William M

2016-05-11

Promysalin is a species-specific Pseudomonad metabolite with unique bioactivity. To better understand the mode of action of this natural product, we synthesized 16 analogs utilizing diverted total synthesis (DTS). Our analog studies revealed that the bioactivity of promysalin is sensitive to changes within its hydrogen bond network whereby alteration has drastic biological consequences. The DTS library not only yielded three analogs that retained potency but also provided insights that resulted in the identification of a previously unknown ability of promysalin to bind iron. These findings coupled with previous observations hint at a complex multifaceted role of the natural product within the rhizosphere.

Diverted Total Synthesis of Promysalin Analogs Demonstrates That an Iron-Binding Motif Is Responsible for Its Narrow-Spectrum Antibacterial Activity

PubMed Central

Steele, Andrew D.; Keohane, Colleen E.; Knouse, Kyle W.; Rossiter, Sean E.; Williams, Sierra J.; Wuest, William M.

2016-01-01

Promysalin is a species-specific Pseudomonad metabolite with unique bioactivity. To better understand the mode of action of this natural product, we synthesized 16 analogs utilizing diverted total synthesis (DTS). Our analog studies revealed that the bioactivity of promysalin is sensitive to changes within its hydrogen bond network whereby alteration has drastic biological consequences. The DTS library not only yielded three analogs that retained potency but also provided insights that resulted in the identification of a previously unknown ability of promysalin to bind iron. These findings coupled with previous observations hint at a complex multifaceted role of the natural product within the rhizosphere. PMID:27096543

Synthesis and characterization of Allium cepa L. as photosensitizer of dye-sensitized solar cell

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sutikno, E-mail: smadnasri@yahoo.com; Afrian, Noverdi; Supriadi,

The synthesis and characterization of Allium cepa L. used as natural pigment for natural dye sensitizer of solar cell has successfully done and anthocyanin is extracted. Anthocynin is color pigment of plant which has characteristic absorption spectrum of photon and excites electrons up to pigment molecules. As the anthocyanin absorbed light increases the excited electrons increase as well. The generated current also increases and it leads to the efficiency increase. The energy conversion efficiency of the cells sensitized with dye of Allium cepa L. was 3,045 x 10{sup −4}%. A simple technique was taken to fabricate dye sensitizer solar cellmore » is spincoating.« less

The puzzling spectrum of HD 94509. Sounding out the extremes of Be shell star spectral morphology

NASA Astrophysics Data System (ADS)

Cowley, C. R.; Przybilla, N.; Hubrig, S.

2015-06-01

Context. The spectral features of HD 94509 are highly unusual, adding an extreme to the zoo of Be and shell stars. The shell dominates the spectrum, showing lines typical for spectral types mid-A to early-F, while the presence of a late/mid B-type central star is indicated by photospheric hydrogen line wings and helium lines. Numerous metallic absorption lines have broad wings but taper to narrow cores. They cannot be fit by Voigt profiles. Aims: We describe and illustrate unusual spectral features of this star, and make rough calculations to estimate physical conditions and abundances in the shell. Furthermore, the central star is characterized. Methods: We assume mean conditions for the shell. An electron density estimate is made from the Inglis-Teller formula. Excitation temperatures and column densities for Fe i and Fe ii are derived from curves of growth. The neutral H column density is estimated from high Paschen members. The column densities are compared with calculations made with the photoionization code Cloudy. Atmospheric parameters of the central star are constrained employing non-LTE spectrum synthesis. Results: Overall chemical abundances are close to solar. Column densities of the dominant ions of several elements, as well as excitation temperatures and the mean electron density are well accounted for by a simple model. Several features, including the degree of ionization, are less well described. Conclusions: HD 94509 is a Be star with a stable shell, close to the terminal-age main sequence. The dynamical state of the shell and the unusually shaped, but symmetric line profiles, require a separate study.

Multicarrier orthogonal spread-spectrum (MOSS) data communications

DOEpatents

Smith, Stephen F [London, TN; Dress, William B [Camas, WA

2008-01-01

Systems and methods are described for multicarrier orthogonal spread-spectrum (MOSS) data communication. A method includes individually spread-spectrum modulating at least two of a set of orthogonal frequency division multiplexed carriers, wherein the resulting individually spread-spectrum modulated at least two of a set of orthogonal frequency division multiplexed carriers are substantially mutually orthogonal with respect to both frequency division multiplexing and spread-spectrum modulation.

Synthesis of chlorophyll b: Localization of chlorophyllide a oxygenase and discovery of a stable radical in the catalytic subunit

PubMed Central

Eggink, Laura L; LoBrutto, Russell; Brune, Daniel C; Brusslan, Judy; Yamasato, Akihiro; Tanaka, Ayumi; Hoober, J Kenneth

2004-01-01

Background Assembly of stable light-harvesting complexes (LHCs) in the chloroplast of green algae and plants requires synthesis of chlorophyll (Chl) b, a reaction that involves oxygenation of the 7-methyl group of Chl a to a formyl group. This reaction uses molecular oxygen and is catalyzed by chlorophyllide a oxygenase (CAO). The amino acid sequence of CAO predicts mononuclear iron and Rieske iron-sulfur centers in the protein. The mechanism of synthesis of Chl b and localization of this reaction in the chloroplast are essential steps toward understanding LHC assembly. Results Fluorescence of a CAO-GFP fusion protein, transiently expressed in young pea leaves, was found at the periphery of mature chloroplasts and on thylakoid membranes by confocal fluorescence microscopy. However, when membranes from partially degreened cells of Chlamydomonas reinhardtii cw15 were resolved on sucrose gradients, full-length CAO was detected by immunoblot analysis only on the chloroplast envelope inner membrane. The electron paramagnetic resonance spectrum of CAO included a resonance at g = 4.3, assigned to the predicted mononuclear iron center. Instead of a spectrum of the predicted Rieske iron-sulfur center, a nearly symmetrical, approximately 100 Gauss peak-to-trough signal was observed at g = 2.057, with a sensitivity to temperature characteristic of an iron-sulfur center. A remarkably stable radical in the protein was revealed by an isotropic, 9 Gauss peak-to-trough signal at g = 2.0042. Fragmentation of the protein after incorporation of 125I- identified a conserved tyrosine residue (Tyr-422 in Chlamydomonas and Tyr-518 in Arabidopsis) as the radical species. The radical was quenched by chlorophyll a, an indication that it may be involved in the enzymatic reaction. Conclusion CAO was found on the chloroplast envelope and thylakoid membranes in mature chloroplasts but only on the envelope inner membrane in dark-grown C. reinhardtii cells. Such localization provides further support for the envelope membranes as the initial site of Chl b synthesis and assembly of LHCs during chloroplast development. Identification of a tyrosine radical in the protein provides insight into the mechanism of Chl b synthesis. PMID:15086960

A facile synthesis of poly(aniline-co-o-bromoaniline) copolymer: Characterization and application as semiconducting material

NASA Astrophysics Data System (ADS)

Mahudeswaran, A.; Vivekanandan, J.; Vijayanand, P. S.; Kojima, T.; Kato, S.

2016-01-01

Poly(aniline-co-o-bromoaniline) (p(an-co-o-BrAn)) copolymer has been synthesized using chemical oxidation method in the hydrochloric acid medium. Copolymerization of aniline with o-bromoaniline of different compositions, such as 1:1, 1:2, 2:1, 1:3 and 3:1 molar ratios were prepared. The synthesized copolymer is soluble in polar solvents like dimethyl sulphoxide (DMSO), dimethyl formamide (DMF), Tetrahydrofuran (THF) and 1-methyl 2-pyrrolidone (NMP). The copolymer is analyzed by various characterization techniques, such as FTIR, UV-Visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), conductivity, Differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). FTIR spectrum confirms the characteristic peaks of the copolymer containing benzenoid and quinoid ring stretching. UV spectrum reveals the formation of π-π∗ transition and n-π∗ transition between the energy levels. XRD peaks reveal that the copolymer possesses amorphous nature. Morphological study reveals that the agglomerated particles form globular structure and size of the each particle is about 100 nm. The electrical conductivity of the copolymers is found in the range of 10-5Scm-1. These organic semiconductor materials can be used to fabricate thinner and cheaper environmental friendly optoelectronic devices that will replace the conventional inorganic semiconductors.

Synthesis, spectral characterization and structural studies of a novel O, N, O donor semicarbazone and its binuclear copper complex with hydrogen bond stabilized lattice

NASA Astrophysics Data System (ADS)

Layana, S. R.; Saritha, S. R.; Anitha, L.; Sithambaresan, M.; Sudarsanakumar, M. R.; Suma, S.

2018-04-01

A novel O,N,O donor salicylaldehyde-N4-phenylsemicarbazone, (H2L) has been synthesized and physicochemically characterized. Detailed structural studies of H2L using single crystal X-ray diffraction technique reveals the existence of intra and inter molecular hydrogen bonding interactions, which provide extra stability to the molecule. We have successfully synthesized a binuclear copper(II) complex, [Cu2(HL)2(NO3)(H2O)2]NO3 with phenoxy bridging between the two copper centers. The complex was characterized by elemental analysis, magnetic susceptibility and conductivity measurements, FT-IR, UV-Visible, mass and EPR spectral methods. The grown crystals of the copper complex were employed for the single crystal X-ray diffraction studies. The complex possesses geometrically different metal centers, in which the ligand coordinates through ketoamide oxygen, azomethine nitrogen and deprotonated phenoxy oxygen. The extensive intermolecular hydrogen bonding interactions of the coordinated and the lattice nitrate groups interconnect the complex units to form a 2D supramolecular assembly. The ESI mass spectrum substantiates the existence of 1:1 complex. The g values obtained from the EPR spectrum in frozen DMF suggest dx2 -y2 ground state for the unpaired electron.

Williamson-Hall analysis and optical properties of small sized ZnO nanocrystals

NASA Astrophysics Data System (ADS)

Kalita, Amarjyoti; Kalita, Manos P. C.

2017-08-01

We apply Williamson-Hall (WH) method of X-ray diffraction (XRD) line profile analysis for lattice strain estimation of small sized ZnO nanocrystals (crystallite size≈4 nm). The ZnO nanocrystals are synthesized by room temperature chemical co-precipitation followed by heating at 40 °C. Zinc acetate, sodium hydroxide and 2-mercaptoethanol (ME) are used for the synthesis of the nanocrystals. {100}, {002}, {101} and {200}, {112}, {201} line profiles in the XRD pattern are significantly merged, therefore determination of the full width at half maximum values and peak positions of the line profiles required for WH analysis has been carried out by executing Rietveld refinement of the XRD pattern. Lattice strain of the 4 nm sized ZnO nanocrystals is found to be 5.8×10-3 which is significantly higher as compared to the literature reported values for larger ones (crystallite size≈17-47 nm). Role of ME as capping agent is confirmed by Fourier transform infrared spectroscopy. The band gap of the nanocrystals is determined from the UV-Visible absorption spectrum and is found to be 3.68 eV. The photoluminescence spectrum exhibits emissions in the visible (408 nm-violet, 467 nm-blue and 538 nm-green) regions showing presence of zinc interstitial and oxygen vacancy in the ZnO nanocrystals.

A new tridentate Schiff base Cu(II) complex: synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra.

PubMed

Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

2013-06-01

A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms. Copyright © 2013 Elsevier B.V. All rights reserved.

Synthesis, crystal structure, photoluminescence and electrochemical properties of a sandwiched Ni2Ce complex

NASA Astrophysics Data System (ADS)

Güngör, Seyit Ali; Kose, Muhammet

2017-12-01

In this study, a Ni2Ce complex [(NiL)2Ce(NO3)2](NO3) was synthesized and characterized by spectroscopic and analytical methods. The structure of the complex was determined by single crystal X-ray diffraction study. In the structure of the complex, a Ce(III) ion is sandwiched between the two NiL units, which are virtually parallel to each other. The Ce(III) center is 12-coordinate, surrounded by 12 oxygen atoms; four are from phenolic groups, four from methoxy groups, and four from two bidentate nitrate ligands. Hirshfeld surface analysis was used to evaluate the inter-molecular interactions within the crystal packing. The complex molecules are linked by H⋯ONO2 interactions. The largest contribution is H⋯O/O⋯H with 41.6% contribution and followed by H⋯H contacts with 39.1%. The complex showed an excitation band in the range of 510-580 nm. A band in the range of 520-580 nm observed in the emission spectrum almost completely overlapped. This suggests that the band in the emission spectrum of the complex is not the actual fluorescence emission and is assigned to the Rayleigh scattering band. Electrochemical and thermal behaviours of the complex were also investigated.

[Synthesis and Properties of 1,11,15,25-Tetrahydroxy-4,8,18,22-Di (Bridged Dipropionate Carboxyl) Phthalocyanine Copper].

PubMed

Xia, Dao-cheng; Li, Wan-cheng; Li, Jie-jun; Wang, Gai-ping; Duan, Hong-wei; Ren, Xu-wen; Feng, Kai; Li, Pei-tao; Wang, Hui-fang; Pu, Gai-qin

2015-08-01

In this dissertation, we study the synthesis and character of new substituted Phthalocyanine. Due to the widely application of Pcs in the fields, such as the communication, medical treatment, chemical industry and so on, therefore, they have been a hot topic over several decades by scientists. Nowadays, scientists have prepared thousands of Pcs and their derivatives. However, along with the human society development and the progress in science and technology, the new phthalocyanine with novle characteristics are still the goal of the scientists. In this dissertion, the synthetic methods of the phthlocyanine is improved. The synthesis and characterization of 1,11,15,25-tetrahydroxy-4,8,18,22-di(bridged dipropionate carboxyl) phthalocyanines are reported in this paper. The mixtures of malonic acid and 3,6-dihydroxy-phthalonitrile was added to water under stiriing. Then, a catalyst amount of sulfuric acid was added. The first synthetic precursor, i. e., malonic acid 3,3'-bis(6-hydroxy phthalonitrile) butter, its molecular formula is C19H8N4O6. phthalocyanines was prepared by malonic acid 3,3'-bis(6-hydroxy phthalonitrile) butter and dihydrate zinc acetate, copper acetate monohydrate in n-amyl alcohol, using DBU as a catalyst under the 135 °C, molecular formula of phthalocyanine complexes is C38H16N8O12M. The product was characterized by Ultraviolet-visible (UV/Vis) Spectrum absorption and fluorescence, The results are agreement with the proposed structures. And electrochemical properties were studied.

Tapioca starch: An efficient fuel in gel-combustion synthesis of photocatalytically and anti-microbially active ZnO nanoparticles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ramasami, Alamelu K.; Raja Naika, H.; Nagabhushana, H.

Zinc oxide nanoparticles were synthesized by gel-combustion method using novel bio-fuel tapioca starch pearls, derived from the tubers of Manihotesculenta. The product is characterized using various techniques. The X-ray diffraction pattern correspond to a hexagonal zincite structure. Fourier transform infrared spectrum showed main absorption peaks at 394 and 508 cm{sup −} {sup 1} due to stretching vibration of Zn–O. Ultravoilet–visible spectrum of zinc oxide nanoparticles showed absorption maximum at 373 nm whereas the maximum of the bulk zinc oxide was 377 nm. The morphology of the product was studied using scanning electron microscopy and transmission electron microscopy. The scanning electronmore » microscopic images showed that the products are agglomerated and porous in nature. The transmission electron microscopic images revealed spherical particles of 40–50 nm in diameter. The photocatalytic degradation of methylene blue was examined using zinc oxide nanoparticles and found more efficient in sunlight than ultra-violet light due to reduced band gap. The antibacterial properties of zinc oxide nanoparticles were investigated against four bacterial strains Klebsiella aerogenes, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aereus, where Pseudomonas aeruginosa and Staphylococcus aereus exhibited significant antibacterial activity in agar well diffusion method when compared to positive control. - Highlights: • ZnO nanoparticles have been prepared from a new bio-fuel, tapioca starch by gel combustion method. • XRD pattern revealed hexagonal zincite crystal structure with crystallite size 33 nm. • ZnO nanoparticles exhibited a band gap of 2.70 eV. • The ZnO nanoparticles exhibited superior degradation in sunlight in comparison with UV light. • The product showed a good anti-bacterial activity against two bacterial strains.« less

Synthesis of 4-aminophenyl substituted indole derivatives for the instrumental analysis and molecular docking evaluation studies

NASA Astrophysics Data System (ADS)

Singh, Navneet; Kumar, Keshav

2017-07-01

The Indole has been known to maintain celebrity status since so many decades and has been a centre point at the spectrum of pharmacological research. The present work stimulates an idea of generating a pool of library of lead compounds. The data collected can be used for the mapping of biologically active compounds. The reported derivatives of 4-aminophenyl substituted Indole were prepared by the methods of Fischer Indole synthesis and Vilsemeier reaction followed by screening for instrumental analysis and molecular docking studies. The synthesized compounds 4-(1-(2-phenylhydrazono)ethyl)aniline, 1, 4-(1H-indol-2-yl)aniline, 2 and 2-(4-aminophenyl)-1H-indole-3-carbaldehyde, 3 were found to have remarkable yield and instrumental data analysis and also showed remarkable docked characteristic. The molecular docking studies revealed that ligand (amino acids) of comp. 1, 2 and 3 had been docked successfully on the binding site of the 3JUS protein selected from PDB with H bonding. The molecular docking data showed that compound 1, would possess remarkable biological activity and compd. 2 and 3 would possess mild to moderate biological activity. Thus this research work paves the way to synthesize new derivatives and thus to develop new compounds in future with accurate prediction.

Coriandrum sativum mediated synthesis of silver nanoparticles and evaluation of their biological characteristics

NASA Astrophysics Data System (ADS)

Senthilkumar, N.; Aravindhan, V.; Ruckmani, K.; Vetha Potheher, I.

2018-05-01

Silver (Ag) nanoparticles (NPs) were prepared by percolated green synthesis method using Coriandrum sativum leaf, root, seed and stem extracts and reported its antibacterial activity. The synthesized Ag NPs were confirmed by UV–visible Spectroscopy, Powder x-ray Diffraction (PXRD), Fourier Transform Infra Red (FT-IR) Spectroscopy analyzes. The Maximum absorbance observed around 400–450 nm reveal the characteristic absorbance of Ag NPs. The Dynamic Light Scattering (DLS) analysis shows the stability of synthesized NPs with average size varying from 35 to 53 nm and also zeta potential stability varying from ‑20 to ‑30 mV. The cubic structure, crystalline nature and purity of the material was confirmed by powder x-ray diffraction studies. FT-IR spectrum shows the presence of various functional groups in the resultant material. The Field Emission Scanning Electron Microscopy (FESEM) image shows the surface morphology of the synthesized NPs and the Energy Dispersive x-ray Analysis (EDAX) confirms the presence of silver metal ions. The Coriandrum sativum aqueous extract exhibited excellent antimicrobial activity against Klebsiella pneumoniae (Gram -ve) bacteria. Numerous studies have been made previously in our field of study but optimization has not been carried out by both extract (different parts like leaf, root, seed and stem) and without addition of any external source such as chemicals, heat etc.

Microwave assisted scalable synthesis of titanium ferrite nanomaterials

NASA Astrophysics Data System (ADS)

Shukla, Abhishek; Bhardwaj, Abhishek K.; Singh, S. C.; Uttam, K. N.; Gautam, Nisha; Himanshu, A. K.; Shah, Jyoti; Kotnala, R. K.; Gopal, R.

2018-04-01

Titanium ferrite magnetic nanomaterials are synthesized by one-step, one pot, and scalable method assisted by microwave radiation. Effects of titanium content and microwave exposure time on size, shape, morphology, yield, bonding nature, crystalline structure, and magnetic properties of titanium ferrite nanomaterials are studied. As-synthesized nanomaterials are characterized by X-ray diffraction (XRD), ultraviolet-visible absorption spectroscopy (UV-Vis), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), Raman spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometer measurements. XRD measurements depict the presence of two phases of titanium ferrite into the same sample, where crystallite size increases from ˜33 nm to 37 nm with the increase in titanium concentration. UV-Vis measurement showed broad spectrum in the spectral range of 250-600 nm which reveals that its characteristic peaks lie between ultraviolet and visible region; ATR-FTIR and Raman measurements predict iron-titanium oxide structures that are consistent with XRD results. The micrographs of TEM and selected area electron diffraction patterns show formation of hexagonal shaped particles with a high degree of crystallinity and presence of multi-phase. Energy dispersive spectroscopy measurements confirm that Ti:Fe compositional mass ratio can be controlled by tuning synthesis conditions. Increase of Ti defects into titanium ferrite lattice, either by increasing titanium precursor or by increasing exposure time, enhances its magnetic properties.

Green way genesis of silver nanoparticles using multiple fruit peels waste and its antimicrobial, anti-oxidant and anti-tumor cell line studies

NASA Astrophysics Data System (ADS)

Naganathan, Kiruthika; Thirunavukkarasu, Somanathan

2017-04-01

Green synthesis of silver nanoparticles (SNP) opens a new path to kill and prevent various infectious diseases and also tumor. In this study, we have synthesized silver nanoparticles using multiple fruit peel waste (pomegranate, orange, banana and apple (POBA)). The primarily nanoparticles formation has been confirmed by the color change. The synthesized SNP were analyzed by various physicochemical techniques such as UV- Visible spectroscopy, x-ray diffraction (XRD), fourier transform infra red (FT-IR) spectroscopy and transmission electron microscope (TEM). The formation of SNP was confirmed by its absorbance peak observed at 430 nm in UV-Visible spectrum. Further, the obtained SNP were identified by XRD and TEM, respectively to know the crystalline nature and size and shape of the particles. The activities of SNP were checked with human pathogens (Salmonella, E.coli and Pseudomonas), plant pathogen (Fusarium) and marine pathogen (Aeromonas hydrophila) and also studied the scavenging effect and anticancer properties against MCF-7 cell lines. This studies proves that the SNP prepared from fruit waste peel extract approach appears extremely fast, cost efficient, eco-friendly and alternative for conventional methods of SNP synthesis to promote the usage of these nanoparticles in medicinal application.

Synthesis and characterization of α-NaYF{sub 4}: Yb, Er nanoparticles by reverse microemulsion method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gunaseelan, M.; Senthilselvan, J., E-mail: jsselvan@hotmail.com

2016-05-06

A simple and cost effective reverse microemulsion system was newly designed to synthesis NaYF{sub 4}:20%Yb,2%Er upconverting luminescent nanoparticles. XRD results confirms the cubic structure of NaYF{sub 4} nanophosphor in the as prepared condition without any other impurity phases. The as-prepared sample itself having highly crystalline nanoparticle with well dispersed uniform morphology is the advantage of this reverse microemulsion process. HRTEM images of as prepared and calcined samples revealed spherical nanoclusters morphology with size of ~210 nm and ~245 nm respectively. The characteristic absorption wavelength that occurs at 980 nm due to transition of energy levels {sup 2}F{sub 5/2} to {sup 2}F{sub 7/2} formore » Yb{sup 3+} rare earth ion in as prepared and calcined upconversion nanoparticle confirms the presence of Yb{sup 3+} by UV-Visible spectroscopy which can act as a sensitizer for photonic upconversion. Therefore the absorption at NIR region and emission spectrum at visible region suggests that NaYF{sub 4}:20%Yb,2%Er is suitable for upcoversion process, due to its optical property and chemical stability this material also be useful for bio imaging applications.« less

Injection Locking Techniques for Spectrum Analysis

NASA Astrophysics Data System (ADS)

Gathma, Timothy D.; Buckwalter, James F.

2011-04-01

Wideband spectrum analysis supports future communication systems that reconfigure and adapt to the capacity of the spectral environment. While test equipment manufacturers offer wideband spectrum analyzers with excellent sensitivity and resolution, these spectrum analyzers typically cannot offer acceptable size, weight, and power (SWAP). CMOS integrated circuits offer the potential to fully integrate spectrum analysis capability with analog front-end circuitry and digital signal processing on a single chip. Unfortunately, CMOS lacks high-Q passives and wideband resonator tunability that is necessary for heterodyne implementations of spectrum analyzers. As an alternative to the heterodyne receiver architectures, two nonlinear methods for performing wideband, low-power spectrum analysis are presented. The first method involves injecting the spectrum of interest into an array of injection-locked oscillators. The second method employs the closed loop dynamics of both injection locking and phase locking to independently estimate the injected frequency and power.

The design of multirate digital control systems

NASA Technical Reports Server (NTRS)

Berg, M. C.

1986-01-01

The successive loop closures synthesis method is the only method for multirate (MR) synthesis in common use. A new method for MR synthesis is introduced which requires a gradient-search solution to a constrained optimization problem. Some advantages of this method are that the control laws for all control loops are synthesized simultaneously, taking full advantage of all cross-coupling effects, and that simple, low-order compensator structures are easily accomodated. The algorithm and associated computer program for solving the constrained optimization problem are described. The successive loop closures , optimal control, and constrained optimization synthesis methods are applied to two example design problems. A series of compensator pairs are synthesized for each example problem. The succesive loop closure, optimal control, and constrained optimization synthesis methods are compared, in the context of the two design problems.

Novel Maximum-based Timing Acquisition for Spread-Spectrum Communications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sibbetty, Taylor; Moradiz, Hussein; Farhang-Boroujeny, Behrouz

This paper proposes and analyzes a new packet detection and timing acquisition method for spread spectrum systems. The proposed method provides an enhancement over the typical thresholding techniques that have been proposed for direct sequence spread spectrum (DS-SS). The effective implementation of thresholding methods typically require accurate knowledge of the received signal-to-noise ratio (SNR), which is particularly difficult to estimate in spread spectrum systems. Instead, we propose a method which utilizes a consistency metric of the location of maximum samples at the output of a filter matched to the spread spectrum waveform to achieve acquisition, and does not require knowledgemore » of the received SNR. Through theoretical study, we show that the proposed method offers a low probability of missed detection over a large range of SNR with a corresponding probability of false alarm far lower than other methods. Computer simulations that corroborate our theoretical results are also presented. Although our work here has been motivated by our previous study of a filter bank multicarrier spread-spectrum (FB-MC-SS) system, the proposed method is applicable to DS-SS systems as well.« less

Indium nanoparticles for ultraviolet surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Das, Rupali; Soni, R. K.

2018-05-01

Ultraviolet Surface-enhanced Raman spectroscopy (UVSERS) has emerged as an efficient molecular spectroscopy technique for ultra-sensitive and ultra-low detection of analyte concentration. The generic SERS substrates based on gold and silver nanostructures have been extensively explored for high local electric field enhancement only in visible-NIR region of the electromagnetic spectrum. The template synthesis of controlled nanoscale size metallic nanostructures supporting localized surface plasmon resonance (LSPR) in the UV region have been recently explored due to their ease of synthesis and potential applications in optoelectronic, catalysis and magnetism. Indium (In0) nanoparticles exhibit active surface plasmon resonance (SPR) in ultraviolet (UV) and deep-ultaviolet (DUV) region with optimal absorption losses. This extended accessibility makes indium a promising material for UV plasmonic, chemical sensing and more recently in UV-SERS. In this work, spherical indium nanoparticles (In NPs) were synthesized by modified polyol reduction method using NaBH4 having local surface plasmon resonance near 280 nm. The as-synthesized spherical In0 nanoparticles were then coated with thin silica shells of thickness ˜ 5nm by a modified Stober method protecting the nanoparticles from agglomeration, direct contact with the probed molecules as well as prevent oxidation of the nanoparticles. Morphological evolution of In0 nanoparticles and SiO2 coating were characterized by transmission electron microscope (TEM). An enhanced near resonant shell-isolated SERS activity from thin film of tryptophan (Tryp) molecules deposited on indium coated substrates under 325nm UV excitation was observed. Finite difference time domain (FDTD) method is employed to comprehend the experimental results and simulate the electric field contours which showed amplified electromagnetic field localized around the nanostructures. The comprehensive analysis indicates that indium is a promising alternate exogenous contrast agent for efficient Raman spectroscopy from molecules.

Method of sound synthesis

DOEpatents

Miner, Nadine E.; Caudell, Thomas P.

2004-06-08

A sound synthesis method for modeling and synthesizing dynamic, parameterized sounds. The sound synthesis method yields perceptually convincing sounds and provides flexibility through model parameterization. By manipulating model parameters, a variety of related, but perceptually different sounds can be generated. The result is subtle changes in sounds, in addition to synthesis of a variety of sounds, all from a small set of models. The sound models can change dynamically according to changes in the simulation environment. The method is applicable to both stochastic (impulse-based) and non-stochastic (pitched) sounds.

[Study on phase correction method of spatial heterodyne spectrometer].

PubMed

Wang, Xin-Qiang; Ye, Song; Zhang, Li-Juan; Xiong, Wei

2013-05-01

Phase distortion exists in collected interferogram because of a variety of measure reasons when spatial heterodyne spectrometers are used in practice. So an improved phase correction method is presented. The phase curve of interferogram was obtained through Fourier inverse transform to extract single side transform spectrum, based on which, the phase distortions were attained by fitting phase slope, so were the phase correction functions, and the convolution was processed between transform spectrum and phase correction function to implement spectrum phase correction. The method was applied to phase correction of actually measured monochromatic spectrum and emulational water vapor spectrum. Experimental results show that the low-frequency false signals in monochromatic spectrum fringe would be eliminated effectively to increase the periodicity and the symmetry of interferogram, in addition when the continuous spectrum imposed phase error was corrected, the standard deviation between it and the original spectrum would be reduced form 0.47 to 0.20, and thus the accuracy of spectrum could be improved.

Analysis of axial compressive loaded beam under random support excitations

NASA Astrophysics Data System (ADS)

Xiao, Wensheng; Wang, Fengde; Liu, Jian

2017-12-01

An analytical procedure to investigate the response spectrum of a uniform Bernoulli-Euler beam with axial compressive load subjected to random support excitations is implemented based on the Mindlin-Goodman method and the mode superposition method in the frequency domain. The random response spectrum of the simply supported beam subjected to white noise excitation and to Pierson-Moskowitz spectrum excitation is investigated, and the characteristics of the response spectrum are further explored. Moreover, the effect of axial compressive load is studied and a method to determine the axial load is proposed. The research results show that the response spectrum mainly consists of the beam's additional displacement response spectrum when the excitation is white noise; however, the quasi-static displacement response spectrum is the main component when the excitation is the Pierson-Moskowitz spectrum. Under white noise excitation, the amplitude of the power spectral density function decreased as the axial compressive load increased, while the frequency band of the vibration response spectrum increased with the increase of axial compressive load.

Hybrid spread spectrum radio system

DOEpatents

Smith, Stephen F [London, TN; Dress, William B [Camas, WA

2010-02-09

Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

Parent skills training for parents of children or adults with developmental disorders: systematic review and meta-analysis protocol.

PubMed

Reichow, Brian; Kogan, Cary; Barbui, Corrado; Smith, Isaac; Yasamy, M Taghi; Servili, Chiara

2014-08-27

Developmental disorders, including intellectual disability and autism spectrum disorders, may limit an individual's capacity to conduct daily activities. The emotional and economic burden on families caring for an individual with a developmental disorder is substantial, and quality of life may be limited by a lack of services. Therefore, finding effective treatments to help this population should be a priority. Recent work has shown parent skills training interventions improve developmental, behavioural and family outcomes. The purpose of this review protocol is to extend previous findings by systematically analysing randomised controlled trials of parent skills training programmes for parents of children with developmental disorders including intellectual disabilities and autism spectrum disorders and use meta-analytic techniques to identify programme components reliably associated with successful outcomes of parent skills training programmes. We will include all studies conducted using randomised control trials designs that compare a group of parents receiving a parent skills training programme to a group of parents in a no-treatment control, waitlist control or treatment as usual comparison group. To locate studies, we will conduct an extensive electronic database search and then use snowball methods, with no limits to publication year or language. We will present a narrative synthesis including visual displays of study effects on child and parental outcomes and conduct a quantitative synthesis of the effects of parent skills training programmes using meta-analytic techniques. No ethical issues are foreseen and ethical approval is not required given this is a protocol for a systematic review. The findings of this study will be disseminated through peer-reviewed publications and international conference presentations. Updates of the review will be conducted, as necessary, to inform and guide practice. PROSPERO (CRD42014006993). Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

PubMed

Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L

2015-04-01

The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

Photochemical reactions of aromatic compounds and the concept of the photon as a traceless reagent.

PubMed

Hoffmann, Norbert

2012-11-01

Electronic excitation significantly changes the reactivity of chemical compounds. Compared to ground state reactions, photochemical reactions considerably enlarge the application spectrum of a particular functional group in organic synthesis. Multistep syntheses may be simplified and perspectives for target oriented synthesis (TOS) and diversity oriented synthesis (DOS) are developed. New compound families become available or may be obtained more easily. In contrast to common chemical reagents, photons don't generate side products resulting from the transformation of a chemical reagent. Therefore, they are considered as a traceless reagent. Consequently, photochemical reactions play a central role in the methodology of sustainable chemistry. This aspect has been recognized since the beginning of the 20th century. As with many other photochemical transformations, photochemical reactions of aromatic, benzene-like compounds illustrate well the advantages in this context. Photochemical cycloadditions of aromatic compounds have been investigated for a long time. Currently, they are applied in various fields of organic synthesis. They are also studied in supramolecular structures. The phenomena of reactivity and stereoselectivity are investigated. During recent years, photochemical electron transfer mediated reactions are particularly focused. Such transformations have likewise been performed with aromatic compounds. Reactivity and selectivity as well as application to organic synthesis are studied.

Speech Analysis and Synthesis Based on Pitch-Synchronous Segmentation of the Speech Waveform.

DTIC Science & Technology

1994-11-09

95.1 Nasality Distinguishes /n/ from /d/, /m/ from /b/, etc. 96.1 99.2 96.9 99.2 Sustention Distinguishes /ffrom /p/, 86.7 91.4 82.8 92.7/b/ from /v...first incoming pitch waveform becomes the first template, and it is stored in memory . Step 2: The amplitude spectrum of the next incoming pitch waveform

Serotonin and Early Cognitive Development: Variation in the Tryptophan Hydroxylase 2 Gene Is Associated with Visual Attention in 7-Month-Old Infants

ERIC Educational Resources Information Center

Leppanen, Jukka M.; Peltola, Mikko J.; Puura, Kaija; Mantymaa, Mirjami; Mononen, Nina; Lehtimaki, Terho

2011-01-01

Background: Allelic variation in the promoter region of a gene that encodes tryptophan hydroxylase isoform 2 (TPH2), a rate-limiting enzyme of serotonin synthesis in the central nervous system, has been associated with variations in cognitive function and vulnerability to affective spectrum disorders. Little is known about the effects of this gene…

Worked examples of alternative methods for the synthesis of qualitative and quantitative research in systematic reviews

PubMed Central

Lucas, Patricia J; Baird, Janis; Arai, Lisa; Law, Catherine; Roberts, Helen M

2007-01-01

Background The inclusion of qualitative studies in systematic reviews poses methodological challenges. This paper presents worked examples of two methods of data synthesis (textual narrative and thematic), used in relation to one review, with the aim of enabling researchers to consider the strength of different approaches. Methods A systematic review of lay perspectives of infant size and growth was conducted, locating 19 studies (including both qualitative and quantitative). The data extracted from these were synthesised using both a textual narrative and a thematic synthesis. Results The processes of both methods are presented, showing a stepwise progression to the final synthesis. Both methods led us to similar conclusions about lay views toward infant size and growth. Differences between methods lie in the way they dealt with study quality and heterogeneity. Conclusion On the basis of the work reported here, we consider textual narrative and thematic synthesis have strengths and weaknesses in relation to different research questions. Thematic synthesis holds most potential for hypothesis generation, but may obscure heterogeneity and quality appraisal. Textual narrative synthesis is better able to describe the scope of existing research and account for the strength of evidence, but is less good at identifying commonality. PMID:17224044

Multishaker modal testing

NASA Technical Reports Server (NTRS)

Craig, R. R., Jr.

1985-01-01

A component mode synthesis method for damped structures was developed and modal test methods were explored which could be employed to determine the relevant parameters required by the component mode synthesis method. Research was conducted on the following topics: (1) Development of a generalized time-domain component mode synthesis technique for damped systems; (2) Development of a frequency-domain component mode synthesis method for damped systems; and (3) Development of a system identification algorithm applicable to general damped systems. Abstracts are presented of the major publications which have been previously issued on these topics.

Synthesis of the human insulin gene. Part III. Chemical synthesis of 5'-phosphomonoester group containing deoxyribooligonucleotides by the modified phosphotriester method. Its application in the synthesis of seventeen fragments constituting human insulin C-chain DNA.

PubMed Central

Hsiung, H M; Sung, W L; Brousseau, R; Wu, R; Narang, S A

1980-01-01

A method for phosphorylating a protected deoxyribooligonucleotide containing phosphotriester linkages is described. The modified phosphotriester method of chemical synthesis is further refined in terms of (i) better final deblocking conditions and (ii) new chromatography solvent systems containing acetone-water-ethyl acetate to yield pure oligomers. The effectiveness of these improvements has been demonstrated in the rapid and efficient synthesis of seventeen fragments constituting the sequence of human insulin C-chain DNA. Images PMID:7008029

A molecular cross-linking approach for hybrid metal oxides.

PubMed

Jung, Dahee; Saleh, Liban M A; Berkson, Zachariah J; El-Kady, Maher F; Hwang, Jee Youn; Mohamed, Nahla; Wixtrom, Alex I; Titarenko, Ekaterina; Shao, Yanwu; McCarthy, Kassandra; Guo, Jian; Martini, Ignacio B; Kraemer, Stephan; Wegener, Evan C; Saint-Cricq, Philippe; Ruehle, Bastian; Langeslay, Ryan R; Delferro, Massimiliano; Brosmer, Jonathan L; Hendon, Christopher H; Gallagher-Jones, Marcus; Rodriguez, Jose; Chapman, Karena W; Miller, Jeffrey T; Duan, Xiangfeng; Kaner, Richard B; Zink, Jeffrey I; Chmelka, Bradley F; Spokoyny, Alexander M

2018-04-01

There is significant interest in the development of methods to create hybrid materials that transform capabilities, in particular for Earth-abundant metal oxides, such as TiO 2 , to give improved or new properties relevant to a broad spectrum of applications. Here we introduce an approach we refer to as 'molecular cross-linking', whereby a hybrid molecular boron oxide material is formed from polyhedral boron-cluster precursors of the type [B 12 (OH) 12 ] 2- . This new approach is enabled by the inherent robustness of the boron-cluster molecular building block, which is compatible with the harsh thermal and oxidizing conditions that are necessary for the synthesis of many metal oxides. In this work, using a battery of experimental techniques and materials simulation, we show how this material can be interfaced successfully with TiO 2 and other metal oxides to give boron-rich hybrid materials with intriguing photophysical and electrochemical properties.

Iodine-catalyzed Csp3-H functionalization of methylhetarenes: One-pot synthesis and cytotoxic evaluation of heteroarenyl-benzimidazoles and benzothiazole.

PubMed

Baig, Mirza Feroz; Shaik, Siddiq Pasha; Nayak, V Lakshma; Alarifi, Abdullah; Kamal, Ahmed

2017-09-01

An efficient one-pot synthetic procedure has been developed for the preparation of heteroarenyl-benzimidazoles via oxidative C sp3 -H functionalization with o-phenylenediamine using I 2 -DMSO in open air from easily available starting materials. Based on a logical plan a spectrum of multi fundamental reactions like iodination, Kornblum oxidation and amination were brought into one-pot. By using this simple method a library of heteroarenyl-benzimidazoles derivatives (3a-t and 5a-g) and heteroarenyl-benzothiazole (3u) have been synthesized in good to excellent yield and screened for their cytotoxicity against a group of four human cancer cell lines. Among them 3h, 3q and 5b showed significant cytotoxic activities with an IC 50 of 1.69, 1.62 and 2.81µM respectively against lung cancer (A549) cell line. Copyright © 2017 Elsevier Ltd. All rights reserved.

Morphological control of seedlessly-synthesized gold nanorods using binary surfactants

NASA Astrophysics Data System (ADS)

Roach, Lucien; Ye, Sunjie; Moorcroft, Samuel C. T.; Critchley, Kevin; Coletta, P. Louise; Evans, Stephen D.

2018-04-01

High purity gold nanorods (AuNRs) with tunable morphology have been synthesized through a binary-surfactant seedless method, which enables the formation of monocrystalline AuNRs with diameters between 7 and 35 nm. The protocol has high shape yield and monodispersity, demonstrating good reproducibility and scalability allowing synthesis of batches 0.5 l in volume. Morphological control has been achieved through the adjustment of the molar concentrations of cetyltrimethylammonium bromide and sodium oleate in the growth solution, providing fine tuning of the optical scattering and absorbance properties of the AuNRs across the visible and NIR spectrum. Sodium oleate was found to provide greatest control over the aspect ratio (and hence optical properties) with concentration changes between 10 and 23 mM leading to variation in the aspect ratio between 2.8 and 4.8. Changes in the geometry of the end-caps were also observed as a result of manipulating the two surfactant concentrations.

Analysis of spectra using correlation functions

NASA Technical Reports Server (NTRS)

Beer, Reinhard; Norton, Robert H.

1988-01-01

A novel method is presented for the quantitative analysis of spectra based on the properties of the cross correlation between a real spectrum and either a numerical synthesis or laboratory simulation. A new goodness-of-fit criterion called the heteromorphic coefficient H is proposed that has the property of being zero when a fit is achieved and varying smoothly through zero as the iteration proceeds, providing a powerful tool for automatic or near-automatic analysis. It is also shown that H can be rendered substantially noise-immune, permitting the analysis of very weak spectra well below the apparent noise level and, as a byproduct, providing Doppler shift and radial velocity information with excellent precision. The technique is in regular use in the Atmospheric Trace Molecule Spectroscopy (ATMOS) project and operates in an interactive, realtime computing environment with turn-around times of a few seconds or less.

Tritium in [15O]water, its identification and removal.

PubMed

Sasaki, T; Ishii, S; Tomiyoshi, K; Ido, T; Miyauchi, J; Senda, M

2000-02-01

The present investigation was undertaken to identify the long-lived radionuclide and its chemical forms existing in [15O]water which was synthesized from 15O produced by the nuclear reaction 14N(d,n)15O, and to develop a method for its removal to facilitate radioactive waste disposal. The long-lived nuclide was identified as tritium based on a comparison of its physical half-life and the energy spectrum of beta-rays with those of tritium. The major chemical form of tritium in the target gas was estimated to be molecular hydrogen. The tritium radioactivity was completely removed without a serious loss occurring to the yield of [15O]water by passing the irradiated target gas over a heated palladium catalyst followed by a calcium chloride column before the final synthesis of the [15O]water. This provided a practical way of removing tritium from the [15O]water.

A molecular cross-linking approach for hybrid metal oxides

NASA Astrophysics Data System (ADS)

Jung, Dahee; Saleh, Liban M. A.; Berkson, Zachariah J.; El-Kady, Maher F.; Hwang, Jee Youn; Mohamed, Nahla; Wixtrom, Alex I.; Titarenko, Ekaterina; Shao, Yanwu; McCarthy, Kassandra; Guo, Jian; Martini, Ignacio B.; Kraemer, Stephan; Wegener, Evan C.; Saint-Cricq, Philippe; Ruehle, Bastian; Langeslay, Ryan R.; Delferro, Massimiliano; Brosmer, Jonathan L.; Hendon, Christopher H.; Gallagher-Jones, Marcus; Rodriguez, Jose; Chapman, Karena W.; Miller, Jeffrey T.; Duan, Xiangfeng; Kaner, Richard B.; Zink, Jeffrey I.; Chmelka, Bradley F.; Spokoyny, Alexander M.

2018-03-01

There is significant interest in the development of methods to create hybrid materials that transform capabilities, in particular for Earth-abundant metal oxides, such as TiO2, to give improved or new properties relevant to a broad spectrum of applications. Here we introduce an approach we refer to as `molecular cross-linking', whereby a hybrid molecular boron oxide material is formed from polyhedral boron-cluster precursors of the type [B12(OH)12]2-. This new approach is enabled by the inherent robustness of the boron-cluster molecular building block, which is compatible with the harsh thermal and oxidizing conditions that are necessary for the synthesis of many metal oxides. In this work, using a battery of experimental techniques and materials simulation, we show how this material can be interfaced successfully with TiO2 and other metal oxides to give boron-rich hybrid materials with intriguing photophysical and electrochemical properties.

Synthesis of nanocrystalline CdS thin film by SILAR and their characterization

NASA Astrophysics Data System (ADS)

Mukherjee, A.; Satpati, B.; Bhattacharyya, S. R.; Ghosh, R.; Mitra, P.

2015-01-01

Cadmium sulphide (CdS) thin film was prepared by successive ion layer adsorption and reaction (SILAR) technique using ammonium sulphide as anionic precursor. Characterization techniques of XRD, SEM, TEM, FTIR and EDX were utilized to study the microstructure of the films. Structural characterization by x-ray diffraction reveals the polycrystalline nature of the films. Cubic structure is revealed from X-ray diffraction and selected area diffraction (SAD) patterns. The particle size estimated using X-ray line broadening method is approximately 7 nm. Instrumental broadening was taken into account while particle size estimation. TEM shows CdS nanoparticles in the range 5-15 nm. Elemental mapping using EFTEM reveals good stoichiometric composition of CdS. Characteristic stretching vibration mode of CdS was observed in the absorption band of FTIR spectrum. Optical absorption study exhibits a distinct blue shift in band gap energy value of about 2.56 eV which confirms the size quantization.

A novel green and template free approach for the synthesis of gold nanorice and its utilization as a catalyst for the degradation of hazardous dye

NASA Astrophysics Data System (ADS)

Sinha, Tanur; Ahmaruzzaman, M.

2015-05-01

Herein, we describe a simple, green and template free method for the production of rice shaped gold nanostructures using an aqueous extract of the egg shells of Anas platyrhynchos. The synthesized nanoparticles were characterized by UV-visible, transmission electron microscopy (TEM), selected area electron diffraction pattern (SAED) and FT-IR studies. The UV-visible spectrum of the synthesized gold nanostructures showed a transverse mode surface plasmon resonance peaks (SPR) at around 540 nm and a longitudinal mode at 880 nm. The TEM and SAED pattern confirmed the morphology, size and crystallographic structure of the synthesized gold nanorice. The synthesized gold nanorice was utilized for the removal of a toxic Eosin Y dye by photodegradation. It was observed that the dye was degraded completely within 1 h and the percentage efficiency was found to be 96.1%.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salii, R. A.; Mintairov, S. A.; Brunkov, P. N.

The specific features of growth in the InAs-GaAs system by the metal-organic chemical vapor deposition method are studied. The dependences of the In content of the InxGa{sub 1−x}As solid solution and of the InAs growth rate on the molar flow of In in a wide temperature range (480–700°C) are determined. The growth processes of InAs quantum dots (QDs) on GaAs with different surface misorientations are examined. The conditions are found in which InAs QDs are formed with a small number of defects and at a high density on a GaAs “sublayer” grown at a high rate. An epitaxial technique ismore » developed for the synthesis of InAs QDs with multimodal size distribution and an extended photoluminescence spectrum, which can be effectively used in designing solar cells with QDs in the active region.« less

Brief Report: Whole Blood Serotonin Levels and Gastrointestinal Symptoms in Autism Spectrum Disorder.

PubMed

Marler, Sarah; Ferguson, Bradley J; Lee, Evon Batey; Peters, Brittany; Williams, Kent C; McDonnell, Erin; Macklin, Eric A; Levitt, Pat; Gillespie, Catherine Hagan; Anderson, George M; Margolis, Kara Gross; Beversdorf, David Q; Veenstra-VanderWeele, Jeremy

2016-03-01

Elevated whole blood serotonin levels are observed in more than 25% of children with autism spectrum disorder (ASD). Co-occurring gastrointestinal (GI) symptoms are also common in ASD but have not previously been examined in relationship with hyperserotonemia, despite the synthesis of serotonin in the gut. In 82 children and adolescents with ASD, we observed a correlation between a quantitative measure of lower GI symptoms and whole blood serotonin levels. No significant association was seen between functional constipation diagnosis and serotonin levels in the hyperserotonemia range, suggesting that this correlation is not driven by a single subgroup. More specific assessment of gut function, including the microbiome, will be necessary to evaluate the contribution of gut physiology to serotonin levels in ASD.

Solar Synthesis: Prospects in Visible Light Photocatalysis

PubMed Central

Schultz, Danielle M.; Yoon, Tehshik P.

2015-01-01

Chemists have long aspired to synthesize molecules the way that plants do — using sunlight to facilitate the construction of complex molecular architectures. Nevertheless, the use of visible light in photochemical synthesis is fundamentally challenging because organic molecules tend not to interact with the wavelengths of visible light that are most strongly emitted in the solar spectrum. Recent research has begun to leverage the ability of visible light absorbing transition metal complexes to catalyze a broad range of synthetically valuable reactions. In this review, we highlight how an understanding of the mechanisms of photocatalytic activation available to these transition metal complexes, and of the general reactivity patterns of the intermediates accessible via visible light photocatalysis, has accelerated the development of this diverse suite of reactions. PMID:24578578

Optimization for rapid synthesis of silver nanoparticles and its effect on phytopathogenic fungi

NASA Astrophysics Data System (ADS)

Krishnaraj, C.; Ramachandran, R.; Mohan, K.; Kalaichelvan, P. T.

In this present study, silver nanoparticles were synthesized by green chemistry approach using Acalypha indica leaf extract as reducing agents. The reaction medium employed in the synthesis process was optimized to attain better yield, controlled size and stability. Further, the biosynthesized silver nanoparticles were conformed through UV-vis spectrum, XRD and HR-TEM analyses. Different concentration of silver nanoparticles were tested to know the inhibitory effect of fungal plant pathogens namely Alternaria alternata, Sclerotinia sclerotiorum, Macrophomina phaseolina, Rhizoctonia solani, Botrytis cinerea and Curvularia lunata. Interestingly, 15 mg concentration of silver nanoparticles showed excellent inhibitory activity against all the tested pathogens. Thus, the obtained results clearly suggest that silver nanoparticles may have important applications in controlling various plant diseases caused by fungi.

Solar synthesis: prospects in visible light photocatalysis.

PubMed

Schultz, Danielle M; Yoon, Tehshik P

2014-02-28

Chemists have long aspired to synthesize molecules the way that plants do-using sunlight to facilitate the construction of complex molecular architectures. Nevertheless, the use of visible light in photochemical synthesis is fundamentally challenging because organic molecules tend not to interact with the wavelengths of visible light that are most strongly emitted in the solar spectrum. Recent research has begun to leverage the ability of visible light-absorbing transition metal complexes to catalyze a broad range of synthetically valuable reactions. In this review, we highlight how an understanding of the mechanisms of photocatalytic activation available to these transition metal complexes, and of the general reactivity patterns of the intermediates accessible via visible light photocatalysis, has accelerated the development of this diverse suite of reactions.

Synthesis of cobalt ferrite nanoparticles from thermolysis of prospective metal-nitrosonaphthol complexes and their photochemical application in removing methylene blue

NASA Astrophysics Data System (ADS)

Tavana, Jalal; Edrisi, Mohammad

2016-03-01

In this study, cobalt ferrite (CoFe2O4) nanoparticles were synthesized by two novel methods. The first method is based on the thermolysis of metal-NN complexes. In the second method, a template free sonochemical treatment of mixed cobalt and iron chelates of α-nitroso-β-naphthol (NN) was applied. Products prepared through method 1 were spherical, with high specific surface area (54.39 m2 g-1) and small average crystalline size of 13 nm. However, CoFe2O4 nanoparticles prepared by method 2 were in random shapes, a broad range of crystalline sizes and a low specific surface area of 25.46 m2 g-1 though highly pure. A Taguchi experimental design was implemented in method 1 to determine and obtain the optimum catalyst. The structural and morphological properties of products were investigated by x-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared, Brunauer-Emmett-Teller and dynamic laser light scattering. The crystalline size calculations were performed using Williamson-Hall method on XRD spectrum. The photocatalytic activity of the optimum nanocrystalline cobalt ferrite was investigated for degradation of a representative pollutant, methylene blue (MB), and visible light as energy source. The results showed that some 92% degradation of MB could be achieved for 7 h of visible light irradiation.

The GALAH Survey: Second Data Release

NASA Astrophysics Data System (ADS)

Buder, Sven; Asplund, Martin; Duong, Ly; Kos, Janez; Lind, Karin; Ness, Melissa K.; Sharma, Sanjib; Bland-Hawthorn, Joss; Casey, Andrew R.; De Silva, Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.; Lewis, Geraint F.; Lin, Jane; Martell, Sarah L.; Schlesinger, Katharine J.; Simpson, Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaž; Amarsi, Anish M.; Anguiano, Borja; Carollo, Daniela; Casagrande, Luca; Čotar, Klemen; Cottrell, Peter L.; Da Costa, Gary; Gao, Xudong D.; Hayden, Michael R.; Horner, Jonathan; Ireland, Michael J.; Kafle, Prajwal R.; Munari, Ulisse; Nataf, David M.; Nordlander, Thomas; Stello, Dennis; Ting, Yuan-Sen; Traven, Gregor; Watson, Fred; Wittenmyer, Robert A.; Wyse, Rosemary F. G.; Yong, David; Zinn, Joel C.; Žerjal, Maruša

2018-05-01

The Galactic Archaeology with HERMES (GALAH) survey is a large-scale stellar spectroscopic survey of the Milky Way, designed to deliver complementary chemical information to a large number of stars covered by the Gaia mission. We present the GALAH second public data release (GALAH DR2) containing 342,682 stars. For these stars, the GALAH collaboration provides stellar parameters and abundances for up to 23 elements to the community. Here we present the target selection, observation, data reduction and detailed explanation of how the spectra were analysed to estimate stellar parameters and element abundances. For the stellar analysis, we have used a multi-step approach. We use the physics-driven spectrum synthesis of Spectroscopy Made Easy (SME) to derive stellar labels (Teff, log g, [Fe/H], [X/Fe], vmic, vsin i, A_{K_S}) for a representative training set of stars. This information is then propagated to the whole sample with the data-driven method of The Cannon. Special care has been exercised in the spectral synthesis to only consider spectral lines that have reliable atomic input data and are little affected by blending lines. Departures from local thermodynamic equilibrium (LTE) are considered for several key elements, including Li, O, Na, Mg, Al, Si, and Fe, using 1D MARCS stellar atmosphere models. Validation tests including repeat observations, Gaia benchmark stars, open and globular clusters, and K2 asteroseismic targets lend confidence to our methods and results. Combining the GALAH DR2 catalogue with the kinematic information from Gaia will enable a wide range of Galactic Archaeology studies, with unprecedented detail, dimensionality, and scope.

M3Ag17(SPh)12 Nanoparticles and Their Structure Prediction.

PubMed

Wickramasinghe, Sameera; Atnagulov, Aydar; Conn, Brian E; Yoon, Bokwon; Barnett, Robert N; Griffith, Wendell P; Landman, Uzi; Bigioni, Terry P

2015-09-16

Although silver nanoparticles are of great fundamental and practical interest, only one structure has been determined thus far: M4Ag44(SPh)30, where M is a monocation, and SPh is an aromatic thiolate ligand. This is in part due to the fact that no other molecular silver nanoparticles have been synthesized with aromatic thiolate ligands. Here we report the synthesis of M3Ag17(4-tert-butylbenzene-thiol)12, which has good stability and an unusual optical spectrum. We also present a rational strategy for predicting the structure of this molecule. First-principles calculations support the structural model, predict a HOMO-LUMO energy gap of 1.77 eV, and predict a new "monomer mount" capping motif, Ag(SR)3, for Ag nanoparticles. The calculated optical absorption spectrum is in good correspondence with the measured spectrum. Heteroatom substitution was also used as a structural probe. First-principles calculations based on the structural model predicted a strong preference for a single Au atom substitution in agreement with experiment.

Ionic liquids for nano- and microstructures preparation. Part 2: Application in synthesis.

PubMed

Łuczak, Justyna; Paszkiewicz, Marta; Krukowska, Anna; Malankowska, Anna; Zaleska-Medynska, Adriana

2016-01-01

Ionic liquids (ILs) are widely applied to prepare metal nanoparticles and 3D semiconductor microparticles. Generally, they serve as a structuring agent or reaction medium (solvent), however it was also demonstrated that ILs can play a role of a co-solvent, metal precursor, reducing as well as surface modifying agent. The crucial role and possible types of interactions between ILs and growing particles have been presented in the Part 1 of this review paper. Part 2 of the paper gives a comprehensive overview of recent experimental studies dealing with application of ionic liquids for preparation of metal and semiconductor based nano- and microparticles. A wide spectrum of preparation routes using ionic liquids is presented, including precipitation, sol-gel technique, hydrothermal method, nanocasting and ray-mediated methods (microwave, ultrasound, UV-radiation and γ-radiation). It was found that ionic liquids formed of a 1-butyl-3-methylimidazolium [BMIM] combined with tetrafluoroborate [BF4], hexafluorophosphate [PF6], and bis(trifluoromethanesulfonyl)imide [Tf2N] are the most often used ILs in the synthesis of nano- and microparticles, due to their low melting temperature, low viscosity and good transportation properties. Nevertheless, examples of other IL classes with intrinsic nanoparticles stabilizing abilities such as phosphonium and ammonium derivatives are also presented. Experimental data revealed that structure of ILs (both anion and cation type) affects the size and shape of formed metal particles, and in some cases may even determine possibility of particles formation. The nature of the metal precursor determines its affinity to polar or nonpolar domains of ionic liquid, and therefore, the size of the nanoparticles depends on the size of these regions. Ability of ionic liquids to form varied extended interactions with particle precursor as well as other compounds presented in the reaction media (water, organic solvents etc.) provides nano- and microstructures with different morphologies (0D nanoparticles, 1D nanowires, rods, 2D layers, sheets, and 3D features of molecules). ILs interact efficiently with microwave irradiation, thus even small amount of IL can be employed to increase the dielectric constant of nonpolar solvents used in the synthesis. Thus, combining the advantages of ionic liquids and ray-mediated methods resulted in the development of new ionic liquid-assisted synthesis routes. One of the recently proposed approaches of semiconductor particles preparation is based on the adsorption of semiconductor precursor molecules at the surface of micelles built of ionic liquid molecules playing a role of a soft template for growing microparticles. Copyright © 2015 Elsevier B.V. All rights reserved.

Laser-induced differential normalized fluorescence method for cancer diagnosis

DOEpatents

Vo-Dinh, Tuan; Panjehpour, Masoud; Overholt, Bergein F.

1996-01-01

An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample.

Laser-induced differential normalized fluorescence method for cancer diagnosis

DOEpatents

Vo-Dinh, T.; Panjehpour, M.; Overholt, B.F.

1996-12-03

An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample. 5 figs.

Mapping the Mixed Methods–Mixed Research Synthesis Terrain

PubMed Central

Sandelowski, Margarete; Voils, Corrine I.; Leeman, Jennifer; Crandell, Jamie L.

2012-01-01

Mixed methods–mixed research synthesis is a form of systematic review in which the findings of qualitative and quantitative studies are integrated via qualitative and/or quantitative methods. Although methodological advances have been made, efforts to differentiate research synthesis methods have been too focused on methods and not focused enough on the defining logics of research synthesis—each of which may be operationalized in different ways—or on the research findings themselves that are targeted for synthesis. The conduct of mixed methods–mixed research synthesis studies may more usefully be understood in terms of the logics of aggregation and configuration. Neither logic is preferable to the other nor tied exclusively to any one method or to any one side of the qualitative/quantitative binary. PMID:23066379

Ferrous sulfate based low temperature synthesis and magnetic properties of nickel ferrite nanostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tejabhiram, Y., E-mail: tejabhiram@gmail.com; Pradeep, R.; Helen, A.T.

2014-12-15

Highlights: • Novel low temperature synthesis of nickel ferrite nanoparticles. • Comparison with two conventional synthesis techniques including hydrothermal method. • XRD results confirm the formation of crystalline nickel ferrites at 110 °C. • Superparamagnetic particles with applications in drug delivery and hyperthermia. • Magnetic properties superior to conventional methods found in new process. - Abstract: We report a simple, low temperature and surfactant free co-precipitation method for the preparation of nickel ferrite nanostructures using ferrous sulfate as the iron precursor. The products obtained from this method were compared for their physical properties with nickel ferrites produced through conventional co-precipitationmore » and hydrothermal methods which used ferric nitrate as the iron precursor. X-ray diffraction analysis confirmed the synthesis of single phase inverse spinel nanocrystalline nickel ferrites at temperature as low as 110 °C in the low temperature method. Electron microscopy analysis on the samples revealed the formation of nearly spherical nanostructures in the size range of 20–30 nm which are comparable to other conventional methods. Vibrating sample magnetometer measurements showed the formation of superparamagnetic particles with high magnetic saturation 41.3 emu/g which corresponds well with conventional synthesis methods. The spontaneous synthesis of the nickel ferrite nanoparticles by the low temperature synthesis method was attributed to the presence of 0.808 kJ mol{sup −1} of excess Gibbs free energy due to ferrous sulfate precursor.« less

Discovery of a Broad-Spectrum Antiviral Compound That Inhibits Pyrimidine Biosynthesis and Establishes a Type 1 Interferon-Independent Antiviral State

PubMed Central

Adcock, Robert S.; Schroeder, Chad E.; Chu, Yong-Kyu; Sotsky, Julie B.; Cramer, Daniel E.; Chilton, Paula M.; Song, Chisu; Anantpadma, Manu; Davey, Robert A.; Prodhan, Aminul I.; Yin, Xinmin; Zhang, Xiang

2016-01-01

Viral emergence and reemergence underscore the importance of developing efficacious, broad-spectrum antivirals. Here, we report the discovery of tetrahydrobenzothiazole-based compound 1, a novel, broad-spectrum antiviral lead that was optimized from a hit compound derived from a cytopathic effect (CPE)-based antiviral screen using Venezuelan equine encephalitis virus. Compound 1 showed antiviral activity against a broad range of RNA viruses, including alphaviruses, flaviviruses, influenza virus, and ebolavirus. Mechanism-of-action studies with metabolomics and molecular approaches revealed that the compound inhibits host pyrimidine synthesis and establishes an antiviral state by inducing a variety of interferon-stimulated genes (ISGs). Notably, the induction of the ISGs by compound 1 was independent of the production of type 1 interferons. The antiviral activity of compound 1 was cell type dependent with a robust effect observed in human cell lines and no observed antiviral effect in mouse cell lines. Herein, we disclose tetrahydrobenzothiazole compound 1 as a novel lead for the development of a broad-spectrum, antiviral therapeutic and as a molecular probe to study the mechanism of the induction of ISGs that are independent of type 1 interferons. PMID:27185801

Synthesis and Evaluation of 1,2,4-Triazolo[1,5-a]pyrimidines as Antibacterial Agents Against Enterococcus faecium

PubMed Central

Wang, Huan; Lee, Mijoon; Peng, Zhihong; Blázquez, Blas; Lastochkin, Elena; Kumarasiri, Malika; Bouley, Renee; Chang, Mayland; Mobashery, Shahriar

2015-01-01

Rapid emergence of antibiotic resistance is one of the most challenging global public health concerns. In particular, vancomycin-resistant Enterococcus faecium infections have been increasing in frequency, representing 25% of enterococci infections in intensive care units. A novel class of 1,2,4-triazolo[1,5-a]pyrimidines active against E. faecium is reported herein. We used a three-component Biginelli-like heterocyclization reaction for the synthesis of a series of these derivatives based on reactions of aldehydes, β-dicarbonyl compounds, and 3-alkylthio-5-amino-1,2,4-tria-zoles. The resulting compounds were assayed for antimicrobial activity against the ESKAPE panel of bacteria, followed by investigation of their in vitro activities. These analyses identified a subset of 1,2,4-triazolo[1,5-a]pyrimidines that had good narrow-spectrum antibacterial activity against E. faecium and exhibited metabolic stability with low intrinsic clearance. Macromolecular synthesis assays revealed cell-wall biosynthesis as the target of these antibiotics. PMID:25923368

Synthesis and Photoluminescence of Single-Crystalline Fe(III)-Doped CdS Nanobelts.

PubMed

Kamran, Muhammad Arshad; Zou, Bingsuo; Majid, A; Alharbil, Thamer; Saeed, M A; Abdullah, Ali; Javed, Qurat-ul-ain

2016-04-01

In this paper, we report the synthesis and optical properties of Fe(III) doped CdS nanobelts (NBs) via simple Chemical Vapor Deposition (CVD) technique to explore their potential in nano-optics. The energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis manifested the presence of Fe(III) ions in the NBs subsequently confirmed by the peak shifting to lower phonon energies as recorded by Raman spectra and shorter lifetime in ns. Photoluminescence (PL) spectrum investigations of the single Fe(III)-doped CdS NBs depicted an additional PL peak centered at 573 nm (orange emission) in addition to the bandedge(BE) emission. The redshift and decrease in the BE intensity of the PL peaks, as compared to the bulk CdS, confirmed the quenching of spectra upon Fe doping. The synthesis and orange emission for Fe-doped CdS NBs have been observed for the first time and point out their potential in nanoscale devices.

Fe-based Fischer Tropsch Synthesis of biomass-derived syngas: Effect of synthesis method

Treesearch

Khiet Mai; Thomas Elder; Les Groom; James J. Spivey

2015-01-01

Two 100Fe/4Cu/4K/6Zn catalysts were prepared using two different methods: coprecipitation or impregnation methods. The effect of the preparation methods on the catalyst structure, catalytic properties, and the conversion of biomass-derived syngas via Fischer–Tropsch synthesis was investigated. Syngas was derived from gasifying Southern pine woodchips and had the...

Synthesizing evidence on complex interventions: how meta-analytical, qualitative, and mixed-method approaches can contribute.

PubMed

Petticrew, Mark; Rehfuess, Eva; Noyes, Jane; Higgins, Julian P T; Mayhew, Alain; Pantoja, Tomas; Shemilt, Ian; Sowden, Amanda

2013-11-01

Although there is increasing interest in the evaluation of complex interventions, there is little guidance on how evidence from complex interventions may be reviewed and synthesized, and the relevance of the plethora of evidence synthesis methods to complexity is unclear. This article aims to explore how different meta-analytical approaches can be used to examine aspects of complexity; describe the contribution of various narrative, tabular, and graphical approaches to synthesis; and give an overview of the potential choice of selected qualitative and mixed-method evidence synthesis approaches. The methodological discussions presented here build on a 2-day workshop held in Montebello, Canada, in January 2012, involving methodological experts from the Campbell and Cochrane Collaborations and from other international review centers (Anderson L, Petticrew M, Chandler J, et al. systematic reviews of complex interventions. In press). These systematic review methodologists discussed the broad range of existing methods and considered the relevance of these methods to reviews of complex interventions. The evidence from primary studies of complex interventions may be qualitative or quantitative. There is a wide range of methodological options for reviewing and presenting this evidence. Specific contributions of statistical approaches include the use of meta-analysis, meta-regression, and Bayesian methods, whereas narrative summary approaches provide valuable precursors or alternatives to these. Qualitative and mixed-method approaches include thematic synthesis, framework synthesis, and realist synthesis. A suitable combination of these approaches allows synthesis of evidence for understanding complex interventions. Reviewers need to consider which aspects of complex interventions should be a focus of their review and what types of quantitative and/or qualitative studies they will be including, and this will inform their choice of review methods. These may range from standard meta-analysis through to more complex mixed-method synthesis and synthesis approaches that incorporate theory and/or user's perspectives. Copyright © 2013 Elsevier Inc. All rights reserved.

Renewable Decyl-alcohol Templated Synthesis of Si-Cu Core-Shell Nanocomposite

NASA Astrophysics Data System (ADS)

Salim, M. A.; >H Misran, S. Z.; Shah, N. N. H.; Razak, N. A. A.; >A Manap,

2013-06-01

Monodispersed silica spheres with particles size of ca. 450 nm were successfully synthesized using a modified Stöber method. The synthesized monodispersed silica spheres were successfully coated with copper using modified sol-gel method employing nonsurfactant surface modifiers and catalyst. A renewable palm oil based decyl-alcohol (C10) as nonsurfactant surface modifiers and catalyst were used to modify the silica surfaces prior to coating with copper. The X-ray diffraction patterns of Si-Cu core-shell exhibited a broad peak corresponding to amorphous silica networks and monoclinic CuO phase. It was found that samples modified in the presence of 1 ml catalyst exhibited homogeneous deposition. The surface area of core materials (SiO2) was at ca. 7.04 m2/g and Si-Cu core-shell was at ca. 8.21 m2/g. The band gap of samples prepared with and without catalyst was calculated to be ca. 2.45 eV and ca. 3.90 eV respectively based on the UV-vis absorption spectrum of the product.

Synthesis and NLO studies of novel (2E)-1-(2-bromo-4,5-dimethoxyphenyL)-3-(3-Bromo-4-Fluorophenyl)Prop-2-en-1-one single crystal

NASA Astrophysics Data System (ADS)

Shruthi, C.; Ravindrachary, V.; Prasad, D. Jagadeesh; Guruswamy, B.; Hegde, Shreedatta

2017-05-01

A novel organic nonlinear optical (NLO) material (2E)-1-(2-Bromo-4,5-Dimethoxyphenyl)-3-(3-Bromo-4-Fluorophenyl)Prop-2-en-1-one has been synthesized using Claisen-Schmidth condensation method. The chemical structure of the compound was confirmed by recording its FT-IR spectrum and the functional groups were identified. Single crystals were grown by slow evaporation method and the single crystal XRD study reveals that the compound crystallizes in the monoclinic crystal system with a space group -P 2yn. The observed cell parameters are a = 9.346(5) A°, b = 12.953(7) A°, c = 14.355(8) A°, α = 90°, β = 108.379°(9), γ = 90°. UV-Visible study shows that the compound is transparent in the entire visible region and the absorption takes place in the UV range. The Non linear optical efficiency of the crystal was estimated and it is found to be 0.5 times that of standard KDP crystal.

Synthesis, FTIR, FT-Raman, UV-visible, ab initio and DFT studies on benzohydrazide.

PubMed

Arjunan, V; Rani, T; Mythili, C V; Mohan, S

2011-08-01

A systematic vibrational spectroscopic assignment and analysis of benzohydrazide (BH) has been carried out by using FTIR and FT-Raman spectral data. The vibrational analysis were aided by electronic structure calculations--ab initio (RHF) and hybrid density functional methods (B3LYP and B3PW91) performed with 6-31G(d,p) and 6-311++G(d,p) basis sets. Molecular equilibrium geometries, electronic energies, IR intensities, harmonic vibrational frequencies, depolarization ratios and Raman activities have been computed. Potential energy distribution (PED) and normal mode analysis have also been performed. The assignments proposed based on the experimental IR and Raman spectra have been reviewed and complete assignment of the observed spectra have been proposed. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO and LUMO energies and λ(max) were determined by time-dependent DFT (TD-DFT) method. The geometrical, thermodynamical parameters and absorption wavelengths were compared with the experimental data. The interactions of carbonyl and hydrazide groups on the benzene ring skeletal modes were investigated. Copyright © 2011 Elsevier B.V. All rights reserved.

Chemical genetics - a versatile method to combine science and higher level teaching in molecular genetics.

PubMed

Sandrock, Björn

2012-10-09

Phosphorylation is a key event in many cellular processes like cell cycle, transformation of environmental signals to transcriptional activation or polar growth. The chemical genetics approach can be used to analyse the effect of highly specific inhibition in vivo and is a promising method to screen for kinase targets. We have used this approach to study the role of the germinal centre kinase Don3 during the cell division in the phytopathogenic fungus Ustilago maydis. Due to the easy determination of the don3 phenotype we have chosen this approach for a genetic course for M.Sc. students and for IMPRS (International Max-Planck research school) students. According to the principle of "problem-based learning" the aim of this two-week course is to transfer knowledge about the broad spectrum of kinases to the students and that the students acquire the ability to design their own analog-sensitive kinase of interest. In addition to these training goals, we benefit from these annual courses the synthesis of basic constructs for genetic modification of several kinases in our model system U. maydis.

Microstructure and magnetic properties of MFe{sub 2}O{sub 4} (M = Co, Ni, and Mn) ferrite nanocrystals prepared using colloid mill and hydrothermal method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Wei, E-mail: wangwei@mail.buct.edu.cn; Ding, Zui; Zhao, Xiruo

2015-05-07

Three kinds of spinel ferrite nanocrystals, MFe{sub 2}O{sub 4} (M = Co, Ni, and Mn), are synthesized using colloid mill and hydrothermal method. During the synthesis process, a rapid mixing and reduction of cations with sodium borohydride (NaBH{sub 4}) take place in a colloid mill then through a hydrothermal reaction, a slow oxidation and structural transformation of the spinel ferrite nanocrystals occur. The phase purity and crystal lattice parameters are estimated by X-ray diffraction studies. Scanning electron microscopy and transmission electron microscopy images show the morphology and particle size of the as-synthesized ferrite nanocrystals. Raman spectrum reveals active phonon modesmore » at room temperature, and a shifting of the modes implies cation redistribution in the tetrahedral and octahedral sites. Magnetic measurements show that all the obtained samples exhibit higher saturation magnetization (M{sub s}). Meanwhile, experiments demonstrate that the hydrothermal reaction time has significant effects on microstructure, morphologies, and magnetic properties of the as-synthesized ferrite nanocrystals.« less

Synthesis, characterization, and thermal analysis of a new energetic salt based on 1'-hydroxy-1H,1'H-5,5'-bitetrazol-1-olate

NASA Astrophysics Data System (ADS)

Niu, Chunhuan; Jin, Bo; Shang, Yu; Liu, Qiangqiang; Peng, Rufang

2018-04-01

4-Amino-1,2,4-triazolium 1'-hydroxy-1H,1'H-5,5'-bitetrazol-1-olate (ATHBTO) was synthesized by reacting 4-amino-1,2,4-triazole (AT) and 1H,1‧H-5,5‧-bistetrazole-1,1‧-diolate dihydrate (H2BTO.2H2O). Its crystal structure was characterized through single-crystal X-ray diffraction. Meanwhile, FTIR, 1H NMR, 13C NMR, and elemental analysis were also introduced to analyze its composition. The thermal stability was investigated by differential scanning calorimetry, thermogravimetric analysis, and thermogravimetric tandem infrared spectrum. Results indicated that ATHBTO exhibited excellent resistance to thermal decompositions reaching 511.4 K and had a 64.6% mass loss between 475.7 and 552.3 K. The kinetics parameters were calculated by Kissinger's method and Ozawa-Doyle's method. Moreover, according to the Kamlet-Jacobs formula, the calculated detonation velocity and detonation pressure of ATHBTO attained 8218 m/s and 28.69 GPa, respectively.

Preparation of visible-light-responsive TiO2-xNx photocatalyst by a sol-gel method: analysis of the active center on TiO2 that reacts with NH3.

PubMed

Kuroda, Yasushige; Mori, Toshinori; Yagi, Kazunori; Makihata, Naoko; Kawahara, Yoichiro; Nagao, Mahiko; Kittaka, Shigeharu

2005-08-16

Active reaction centers for ammonia on titanium oxyhydroxide were explored to direct the search for an efficient sol-gel method for the synthesis of a titanium oxynitride (TiO2-xNx) sample with an efficient responsiveness to the visible light constituting a main part of the solar spectrum. The results lead to the conclusion that the site giving IR bands at around 2195 cm(-1) for the adsorbed CO molecules at 300 K is a reactive site and behaves as Lewis acid site in the coordination environment of distorted five-coordinate Ti4+ ions. Ammonia molecules are adsorbed on such a site to form -NH2 and -OH species during the heat treatments at a temperature above 373 K, and they are ultimately incorporated into the TiO2 lattice as nitride through the dehydration at higher temperatures of up to 723 K, resulting in the formation of an anatase type of TiO2-xNx.

Oxygen spectral line synthesis: 3D non-LTE with CO5BOLD hydrodynamical model atmospheres.

NASA Astrophysics Data System (ADS)

Prakapavičius, D.; Steffen, M.; Kučinskas, A.; Ludwig, H.-G.; Freytag, B.; Caffau, E.; Cayrel, R.

In this work we present first results of our current project aimed at combining the 3D hydrodynamical stellar atmosphere approach with non-LTE (NLTE) spectral line synthesis for a number of key chemical species. We carried out a full 3D-NLTE spectrum synthesis of the oxygen IR 777 nm triplet, using a modified and improved version of our NLTE3D package to calculate departure coefficients for the atomic levels of oxygen in a CO5BOLD 3D hydrodynamical solar model atmosphere. Spectral line synthesis was subsequently performed with the Linfor3D code. In agreement with previous studies, we find that the lines of the oxygen triplet produce deeper cores under NLTE conditions, due to the diminished line source function in the line forming region. This means that the solar oxygen IR 777 nm lines should be stronger in NLTE, leading to negative 3D NLTE-LTE abundance corrections. Qualitatively this result would support previous claims for a relatively low solar oxygen abundance. Finally, we outline several further steps that need to be taken in order to improve the physical realism and numerical accuracy of our current 3D-NLTE calculations.

Effects of Chromosomal Integration of the Vitreoscilla Hemoglobin Gene (vgb) and S-Adenosylmethionine Synthetase Gene (metK) on ε-Poly-L-Lysine Synthesis in Streptomyces albulus NK660.

PubMed

Gu, Yanyan; Wang, Xiaomeng; Yang, Chao; Geng, Weitao; Feng, Jun; Wang, Yuanyuan; Wang, Shufang; Song, Cunjiang

2016-04-01

ε-Poly-L-lysine (ε-PL) is a widely used natural food preservative. To test the effects of the Vitreoscilla hemoglobin (VHb) and S-adenosylmethionine (SAM) on ε-PL synthesis in Streptomyces albulus NK660, the heterologous VHb gene (vgb) and SAM synthetase gene (metK) were inserted into the S. albulus NK660 chromosome under the control of the constitutive ermE* promoter. CO-difference spectrum analysis showed S. albulus NK660-VHb strain could express functional VHb. S. albulus NK660-VHb produced 26.67 % higher ε-PL and 14.57 % higher biomass than the wild-type control, respectively. Reversed-phase high-pressure liquid chromatography (RP-HPLC) results showed the overexpression of the metK gene resulted in increased intracellular SAM synthesis in S. albulus NK660-SAM, which caused increases of biomass as well as the transcription level of ε-PL synthetase gene (pls). Results indicated that the expression of vgb and metK gene improved on ε-PL synthesis and biomass for S. albulus NK660, respectively.

Green synthesis of silver nanoparticle and silver based chitosan bionanocomposite using stem extract of Saccharum officinarum and assessment of its antibacterial activity

NASA Astrophysics Data System (ADS)

Paulkumar, Kanniah; Gnanajobitha, Gnanadhas; Vanaja, Mahendran; Pavunraj, Manickam; Annadurai, Gurusamy

2017-09-01

Synthesis of nanoparticles and nanocomposites using green route is a major focus of modern nanotechnology. Herein we demonstrate the synthesis of silver nanoparticle and silver based chitosan bionanocomposite using the stem extract of Saccharum officinarum. The absorbance peak at 460 nm in the UV-Vis spectrum reveals the synthesis of silver nanoparticles using the stem extract of Saccharum officinarum. The size of the synthesized silver nanoparticle was in the range of 10-60 nm obtained from transmission electron microscope (TEM) analysis. The presence of silver nanoparticles on the chitosan suspension was identified by scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDS). The presence of possible functional group involved in the reduction of silver metal ions into silver nanoparticles was identified by Fourier transform infrared spectroscopy (FTIR) analysis. The antibacterial activity of the synthesized silver based chitosan bionanocomposite was evaluated against Bacillus subtilis (MTCC 3053), Klebsiella planticola (MTCC 2277), Streptococcus faecalis (ATCC 8043), Pseudomonas aeruginosa (ATCC 9027) and Escherichia coli (ATCC 8739). The antibacterial activity of silver based chitosan bionanocomposite has remarkable scope in medicine, food packaging, textile and pharmaceuticals.

Music 4C, a multi-voiced synthesis program with instruments defined in C

NASA Astrophysics Data System (ADS)

Beauchamp, James W.

2003-04-01

Music 4C is a program which runs under Unix (including Linux) and provides a means for the synthesis of arbitrary signals as defined by the C code. The program is actually a loose translation of an earlier program, Music 4BF [H. S. Howe, Jr., Electronic Music Synthesis (Norton, 1975)]. A set of instrument definitions are driven by a numerical score which consists of a series of ``events.'' Each event gives an instrument name, start time and duration, and a number of parameters (e.g., pitch) which describe the event. Each instrument definition consists of event parameters, performance variables, initializations, and a synthesis algorithmic code. Thus, the synthetic signal, no matter how complex, is precisely defined. Moreover, the resulting sounds can be overlaid in any arbitrary pattern. The program serves as a mixer of algorithmically produced sounds or recorded sounds taken from sample files or synthesized from spectrum files. A score file can be entered by hand, generated from a program, translated from a MIDI file, or generated from an alpha-numeric score using an auxiliary program, Notepro. Output sample files are in wav, snd, or aiff format. The program is provided in the C source code for download.

Synthesis and characterization of silver nanoparticles using crystal compound of sodium para-hydroxybenzoate tetrahydrate isolated from Vitex negundo. L leaves and its apoptotic effect on human colon cancer cell lines.

PubMed

Durai, Prabhu; Chinnasamy, Arulvasu; Gajendran, Babu; Ramar, Manikandan; Pappu, Srinivasan; Kasivelu, Govindaraju; Thirunavukkarasu, Ashokkumar

2014-09-12

Metallic nanoparticles are major concern, particularly silver nanoparticles (AgNPs) are used in various applications. In the present investigation, we report a novel strategy with biological approach for synthesis of AgNPs using sodium para-hydroxybenzoate tetrahydrate (SPHT) isolated from Vitex negundo leaves. The synthesized SPHT-AgNPs were characterized by UV-vis spectroscopy, high resolution transmission electron microscopy (HRTEM) with selected area electron diffraction (SAED) pattern, field emission scanning electron microscopy (FESEM) with energy-dispersive X-ray spectroscopy (EDX), zeta potential and Fourier transform infrared spectroscopy (FT-IR) analysis. The various pH and temperature were evaluated to find their stability effects on SPHT-AgNPs synthesis peak at 430 nm. The size of SPHT-AgNPs were ranging from 26 to 39 nm and were spherical in shape. The hydroxyl and carboxylic functional groups from bio-reducing mediators of SPHT have a stronger ability towards synthesis of AgNPs, which was confirmed using FT-IR spectrum. In addition, anticancer activity were determined by MTT assay, Annexin V-FITC/PI and cell cycle analysis. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Worked examples of alternative methods for the synthesis of qualitative and quantitative research in systematic reviews.

PubMed

Lucas, Patricia J; Baird, Janis; Arai, Lisa; Law, Catherine; Roberts, Helen M

2007-01-15

The inclusion of qualitative studies in systematic reviews poses methodological challenges. This paper presents worked examples of two methods of data synthesis (textual narrative and thematic), used in relation to one review, with the aim of enabling researchers to consider the strength of different approaches. A systematic review of lay perspectives of infant size and growth was conducted, locating 19 studies (including both qualitative and quantitative). The data extracted from these were synthesised using both a textual narrative and a thematic synthesis. The processes of both methods are presented, showing a stepwise progression to the final synthesis. Both methods led us to similar conclusions about lay views toward infant size and growth. Differences between methods lie in the way they dealt with study quality and heterogeneity. On the basis of the work reported here, we consider textual narrative and thematic synthesis have strengths and weaknesses in relation to different research questions. Thematic synthesis holds most potential for hypothesis generation, but may obscure heterogeneity and quality appraisal. Textual narrative synthesis is better able to describe the scope of existing research and account for the strength of evidence, but is less good at identifying commonality.

A spectrum synthesis program for binary stars

NASA Technical Reports Server (NTRS)

Linnell, Albert P.; Hubeny, Ivan

1994-01-01

A new program produces synthetic spectra of binary stars at arbitrary values of orbital longitude, including longitudes of partial or complete eclipse. The stellar components may be distorted, either tidally or rotationally, or both. Either or both components may be rotating nonsynchronously. We illustrate the program performance with two cases: EE Peg, an eclipsing binary with small distortion, and SX Aur, an eclipsing binary that is close to contact.

Synthesis of Nucleoside Mono- and Dialdehydes as Antiviral Agents

DTIC Science & Technology

1987-12-15

Crimean-Congo Hemorrhagic Fever VSV Vesicular Stomatitis Virus AD2 Adenovirus Type 2 VV Vaccinia FeLV Feline Leukemia Virus HIV Human Immunodeficiency...have shown broad spectrum activity against wainy of the viruses in the screening system, and some, like guanosine diaLdehyde, have shown remarkably...8217-unsaturaited adenosin*-2’,3’-diLsdehyde ahowed excellent activity against vesicular stomatitis virus . 20. DISTRIBUTION /AVAILABILITY OF ABSTRACT 21

Sensitivity Analysis Applied to Atomic Data Used for X-ray Spectrum Synthesis

NASA Technical Reports Server (NTRS)

Kallman, Tim

2006-01-01

A great deal of work has been devoted to the accumulation of accurate quantities describing atomic processes for use in analysis of astrophysical spectra. But in many situations of interest the interpretation of a quantity which is observed, such as a line flux, depends on the results of a modeling- or spectrum synthesis code. The results of such a code depends in turn 011 many atomic rates or cross sections, and the sensitivity of the observable quantity on the various rates and cross sections may be non-linear and if so cannot easily be derived analytically. In such cases the most practical approach to understanding the sensitivity of observables to atomic cross sections is to perform numerical experiments, by calculating models with various rates perturbed by random (but known) factors. In addition, it is useful to compare the results of such experiments with some sample observations, in order to focus attention on the rates which are of the greatest relevance to real observations. In this paper I will present some attempts to carry out this program, focussing on two sample datasets taken with the Chandra HETG. I will discuss the sensitivity of synthetic spectra to atomic data affecting ionization balance, temperature, and line opacity or emissivity, and discuss the implications for the ultimate goal of inferring astrophysical parameters.

Sensitivity Analysis Applied to Atomic Data Used for X-ray Spectrum Synthesis

NASA Technical Reports Server (NTRS)

Kallman, Tim

2006-01-01

A great deal of work has been devoted to the accumulation of accurate quantities describing atomic processes for use in analysis of astrophysical spectra. But in many situations of interest the interpretation of a quantity which is observed, such as a line flux, depends on the results of a modeling- or spectrum synthesis code. The results of such a code depends in turn on many atomic rates or cross sections, and the sensitivity of the observable quantity on the various rates and cross sections may be non-linear and if so cannot easily be derived analytically. In such cases the most practical approach to understanding the sensitivity of observables to atomic cross sections is to perform numerical experiments, by calculating models with various rates perturbed by random (but known) factors. In addition, it is useful to compare the results of such experiments with some sample observations, in order to focus attention on the rates which are of the greatest relevance to real observations. In this paper I will present some attempts to carry out this program, focussing on two sample datasets taken with the Chandra HETG. I will discuss the sensitivity of synthetic spectra to atomic data affecting ionization balance, temperature, and line opacity or emissivity, and discuss the implications for the ultimate goal of inferring astrophysical parameters.

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

DOE PAGES

Schumann, Julia; Kröhnert, Jutta; Frei, Elias; ...

2017-08-28

Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy. Nano-structured, mainly metallic copper was detected on the surface of the Cu/MgO catalyst. In contrast, the high energy of the main peak in the spectrum of CO adsorbed on reduced Cu/ZnO:Al (2125 cm -1) proves that metallic copper is largely absent on the surface of this catalyst. The band is assigned to Zn δ+–CO. The presence of not completely reduced Cu δ+–CO speciesmore » cannot be excluded. The results are interpreted in terms of a partial coverage of the copper nano-particles in the Cu/ZnO:Al catalyst by a thin layer of metastable, defective zinc oxide. Minor contributions in the spectrum at 2090 and 2112 cm -1 due to nano-structured Cu 0–CO and CO adsorbed on highly defective Cu 0, respectively, indicate that the coverage of metallic copper is not complete.« less

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumann, Julia; Kröhnert, Jutta; Frei, Elias

Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy. Nano-structured, mainly metallic copper was detected on the surface of the Cu/MgO catalyst. In contrast, the high energy of the main peak in the spectrum of CO adsorbed on reduced Cu/ZnO:Al (2125 cm -1) proves that metallic copper is largely absent on the surface of this catalyst. The band is assigned to Zn δ+–CO. The presence of not completely reduced Cu δ+–CO speciesmore » cannot be excluded. The results are interpreted in terms of a partial coverage of the copper nano-particles in the Cu/ZnO:Al catalyst by a thin layer of metastable, defective zinc oxide. Minor contributions in the spectrum at 2090 and 2112 cm -1 due to nano-structured Cu 0–CO and CO adsorbed on highly defective Cu 0, respectively, indicate that the coverage of metallic copper is not complete.« less

A Synthesis of the Literature on Research Methods Education

ERIC Educational Resources Information Center

Earley, Mark A.

2014-01-01

The purpose of this research synthesis is to examine the current research on teaching and learning research methods. The aims are to understand the themes present in the current literature and identify gaps in our understanding of how we teach, and how students learn, research methods. A synthesis of 89 studies generated three themes: (1)…

47 CFR 101.521 - Spectrum utilization.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 47 Telecommunication 5 2011-10-01 2011-10-01 false Spectrum utilization. 101.521 Section 101.521... SERVICES 24 GHz Service and Digital Electronic Message Service § 101.521 Spectrum utilization. All... contain detailed descriptions of the modulation method, the channel time sharing method, any error...

[Application of wavelet transform and neural network in the near-infrared spectrum analysis of oil shale].

PubMed

Li, Su-Yi; Ji, Yan-Ju; Liu, Wei-Yu; Wang, Zhi-Hong

2013-04-01

In the present study, an innovative method is proposed, employing both wavelet transform and neural network, to analyze the near-infrared spectrum data in oil shale survey. The method entails using db8 wavelet at 3 levels decomposition to process raw data, using the transformed data as the input matrix, and creating the model through neural network. To verify the validity of the method, this study analyzes 30 synthesized oil shale samples, in which 20 samples are randomly selected for network training, the other 10 for model prediction, and uses the full spectrum and the wavelet transformed spectrum to carry out 10 network models, respectively. Results show that the mean speed of the full spectrum neural network modeling is 570.33 seconds, and the predicted residual sum of squares (PRESS) and correlation coefficient of prediction are 0.006 012 and 0.843 75, respectively. In contrast, the mean speed of the wavelet network modeling method is 3.15 seconds, and the mean PRESS and correlation coefficient of prediction are 0.002 048 and 0.953 19, respectively. These results demonstrate that the wavelet neural network modeling method is significantly superior to the full spectrum neural network modeling method. This study not only provides a new method for more efficient and accurate detection of the oil content of oil shale, but also indicates the potential for applying wavelet transform and neutral network in broad near-infrared spectrum analysis.

Cascade heterogeneous face sketch-photo synthesis via dual-scale Markov Network

NASA Astrophysics Data System (ADS)

Yao, Saisai; Chen, Zhenxue; Jia, Yunyi; Liu, Chengyun

2018-03-01

Heterogeneous face sketch-photo synthesis is an important and challenging task in computer vision, which has widely applied in law enforcement and digital entertainment. According to the different synthesis results based on different scales, this paper proposes a cascade sketch-photo synthesis method via dual-scale Markov Network. Firstly, Markov Network with larger scale is used to synthesise the initial sketches and the local vertical and horizontal neighbour search (LVHNS) method is used to search for the neighbour patches of test patches in training set. Then, the initial sketches and test photos are jointly entered into smaller scale Markov Network. Finally, the fine sketches are obtained after cascade synthesis process. Extensive experimental results on various databases demonstrate the superiority of the proposed method compared with several state-of-the-art methods.

Green synthesis of silver nanoparticles using cell extracts of Anabaena doliolum and screening of its antibacterial and antitumor activity.

PubMed

Singh, Garvita; Babele, Piyoosh K; Shahi, Shailesh K; Sinha, Rajeshwar P; Tyagi, Madhu B; Kumar, Ashok

2014-10-01

In the present work, we describe a simple, cheap, and unexplored method for "green" synthesis of silver nanoparticles using cell extracts of the cyanobacterium Anabaena doliolum. An attempt was also made to test the antimicrobial and antitumor activities of the synthesized nanoparticles. Analytical techniques, namely UV-vis spectroscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and TEMselected area electron diffraction, were used to elucidate the formation and characterization of silver-cyanobacterial nanoparticles (Ag-CNPs). Results showed that the original color of the cell extract changed from reddish blue to dark brown after addition of silver nitrate solution (1 mM) within 1 h, suggesting the synthesis of Ag-CNPs. That the formation Ag-CNPs indeed occurred was also evident from the spectroscopic analysis of the reaction mixture, wherein a prominent peak at 420 nm was noted. TEM images revealed well-dispersed, spherical Ag- CNPs with a particle size in the range of 10-50 nm. The X-ray diffraction spectrum suggested a crystalline nature of the Ag-CNPs. FTIR analysis indicated the utilization of a hydroxyl (-OH) group in the formation of Ag-CNPs. Ag-CNPs exhibited strong antibacterial activity against three multidrug-resistant bacteria. Additionally, Ag-CNPs strongly affected the survival of Dalton's lymphoma and human carcinoma colo205 cells at a very low concentration. The Ag-CNPs-induced loss of survival of both cell types may be due to the induction of reactive oxygen species generation and DNA fragmentation, resulting in apoptosis. Properties exhibited by the Ag-CNP suggest that it may be used as a potential antibacterial and antitumor agent.

Synthesis of optimized indium phosphide/zinc sulfide core/shell nanocrystals and titanium dioxide nanotubes for quantum dot sensitized solar cells

NASA Astrophysics Data System (ADS)

Lee, Seungyong

Synthesis of InP/ZnS core/shell nanocrystals and TiO 2 nanotubes and the optimization study to couple them together were explored for quantum dot sensitized solar cells. Its intrinsic nontoxicity makes the direct band gap InP/ZnS core/shell be one of the most promising semiconductor nanocrystals for optoelectric applications, with the advantage of tuning the optical absorption range in the desired solar spectrum region. Highly luminescent and monodisperse InP/ZnS nanocrystals were synthesized in a non-coordinating solvent. By varying the synthesis scheme, different size InP/ZnS nanocrystals with emission peaks ranging from 520 nm to 620 nm were grown. For the purpose of ensuring air stability, a ZnS shell was grown. The ZnS shell improves the chemical stability in terms of oxidation prevention. Transmission electron microscopy (TEM) image shows that the nanocrystals are highly crystalline and monodisperse. Free-standing TiO2 nanotubes were produced by an anodization method using ammonium fluoride. The free-standing nanotubes were formed under the condition that the chemical dissolution speed associated with fluoride concentration was faster than the speed of Ti oxidation. Highly ordered free-standing anatase form TiO2 nanotubes, which are transformed by annealing at the optimized temperature, are expected to be ideal for coupling with the prepared InP/ZnS nanocrystals. Electrophoretic deposition was carried out to couple the InP/ZnS nanocrystals with the TiO2 nanotubes. Under the adjusted applied voltage condition, the current during the electrophoretic deposition decreased continuously with time. The amount of the deposited nanocrystals was estimated by calculation and the evenly deposited nanocrystals on the TiO2 nanotubes were observed by TEM.

[Signal analysis and spectrum distortion correction for tunable diode laser absorption spectroscopy system].

PubMed

Bao, Wei-Yi; Zhu, Yong; Chen, Jun; Chen, Jun-Qing; Liang, Bo

2011-04-01

In the present paper, the signal of a tunable diode laser absorption spectroscopy (TDLAS) trace gas sensing system, which has a wavelength modulation with a wide range of modulation amplitudes, is studied based on Fourier analysis method. Theory explanation of spectrum distortion induced by laser intensity amplitude modulation is given. In order to rectify the spectrum distortion, a method of synchronous amplitude modulation suppression by a variable optical attenuator is proposed. To validate the method, an experimental setup is designed. Absorption spectrum measurement experiments on CO2 gas were carried out. The results show that the residual laser intensity modulation amplitude of the experimental system is reduced to -0.1% of its original value and the spectrum distortion improvement is 92% with the synchronous amplitude modulation suppression. The modulation amplitude of laser intensity can be effectively reduced and the spectrum distortion can be well corrected by using the given correction method and system. By using a variable optical attenuator in the TDLAS (tunable diode laser absorption spectroscopy) system, the dynamic range requirements of photoelectric detector, digital to analog converter, filters and other aspects of the TDLAS system are reduced. This spectrum distortion correction method can be used for online trace gas analyzing in process industry.

Parametric spectro-temporal analyzer (PASTA) for real-time optical spectrum observation

NASA Astrophysics Data System (ADS)

Zhang, Chi; Xu, Jianbing; Chui, P. C.; Wong, Kenneth K. Y.

2013-06-01

Real-time optical spectrum analysis is an essential tool in observing ultrafast phenomena, such as the dynamic monitoring of spectrum evolution. However, conventional method such as optical spectrum analyzers disperse the spectrum in space and allocate it in time sequence by mechanical rotation of a grating, so are incapable of operating at high speed. A more recent method all-optically stretches the spectrum in time domain, but is limited by the allowable input condition. In view of these constraints, here we present a real-time spectrum analyzer called parametric spectro-temporal analyzer (PASTA), which is based on the time-lens focusing mechanism. It achieves a frame rate as high as 100 MHz and accommodates various input conditions. As a proof of concept and also for the first time, we verify its applications in observing the dynamic spectrum of a Fourier domain mode-locked laser, and the spectrum evolution of a laser cavity during its stabilizing process.

Melanin-templated rapid synthesis of silver nanostructures

PubMed Central

2014-01-01

Background As a potent antimicrobial agent, silver nanostructures have been used in nanosensors and nanomaterial-based assays for the detection of food relevant analytes such as organic molecules, aroma, chemical contaminants, gases and food borne pathogens. In addition silver based nanocomposites act as an antimicrobial for food packaging materials. In this prospective, the food grade melanin pigment extracted from sponge associated actinobacterium Nocardiopsis alba MSA10 and melanin mediated synthesis of silver nanostructures were studied. Based on the present findings, antimicrobial nanostructures can be developed against food pathogens for food industrial applications. Results Briefly, the sponge associated actinobacterium N. alba MSA10 was screened and fermentation conditions were optimized for the production of melanin pigment. The Plackett-Burman design followed by a Box-Behnken design was developed to optimize the concentration of most significant factors for improved melanin yield. The antioxidant potential, reductive capabilities and physiochemical properties of Nocardiopsis melanin was characterized. The optimum production of melanin was attained with pH 7.5, temperature 35°C, salinity 2.5%, sucrose 25 g/L and tyrosine 12.5 g/L under submerged fermentation conditions. A highest melanin production of 3.4 mg/ml was reached with the optimization using Box-Behnken design. The purified melanin showed rapid reduction and stabilization of silver nanostructures. The melanin mediated process produced uniform and stable silver nanostructures with broad spectrum antimicrobial activity against food pathogens. Conclusions The melanin pigment produced by N. alba MSA10 can be used for environmentally benign synthesis of silver nanostructures and can be useful for food packaging materials. The characteristics of broad spectrum of activity against food pathogens of silver nanostructures gives an insight for their potential applicability in incorporation of food packaging materials and antimicrobials for stored fruits and foods. PMID:24885756

Optimal Bandwidth for Multitaper Spectrum Estimation

DOE PAGES

Haley, Charlotte L.; Anitescu, Mihai

2017-07-04

A systematic method for bandwidth parameter selection is desired for Thomson multitaper spectrum estimation. We give a method for determining the optimal bandwidth based on a mean squared error (MSE) criterion. When the true spectrum has a second-order Taylor series expansion, one can express quadratic local bias as a function of the curvature of the spectrum, which can be estimated by using a simple spline approximation. This is combined with a variance estimate, obtained by jackknifing over individual spectrum estimates, to produce an estimated MSE for the log spectrum estimate for each choice of time-bandwidth product. The bandwidth that minimizesmore » the estimated MSE then gives the desired spectrum estimate. Additionally, the bandwidth obtained using our method is also optimal for cepstrum estimates. We give an example of a damped oscillatory (Lorentzian) process in which the approximate optimal bandwidth can be written as a function of the damping parameter. Furthermore, the true optimal bandwidth agrees well with that given by minimizing estimated the MSE in these examples.« less

Analysis and application of Fourier transform spectroscopy in atmospheric remote sensing

NASA Technical Reports Server (NTRS)

Park, J. H.

1984-01-01

An analysis method for Fourier transform spectroscopy is summarized with applications to various types of distortion in atmospheric absorption spectra. This analysis method includes the fast Fourier transform method for simulating the interferometric spectrum and the nonlinear least-squares method for retrieving the information from a measured spectrum. It is shown that spectral distortions can be simulated quite well and that the correct information can be retrieved from a distorted spectrum by this analysis technique.

Synthesis of layered double hydroxides containing Mg2+, Zn2+, Ca2+ and Al3+ layer cations by co-precipitation methods-A review

NASA Astrophysics Data System (ADS)

Theiss, Frederick L.; Ayoko, Godwin A.; Frost, Ray L.

2016-10-01

Co-precipitation is a common method for the preparation of layered double hydroxides (LDHs) and related materials. This review article is aimed at providing newcomers to the field with some examples of the types of co-precipitation reactions that have been reported previously and to briefly investigate some of the properties of the products of these reactions. Due to the sheer volume of literature on the subject, the authors have had to limit this article to the synthesis of Mg/Al, Zn/Al and Ca/Al LDHs by co-precipitation and directly related methods. LDHs have been synthesised from various reagents including metal salts, oxides and hydroxides. Co-precipitation is also useful for the direct synthesis of LDHs with a wide range of interlayer anions and various bases have been successfully employed to prepare LDHs. Examples of other synthesis techniques including the urea method, hydrothermal synthesis and various mechanochemical methods that are undoubtedly related to co-precipitation have also been included in this review. The effect of post synthesis hydrothermal has also been summarised.

Convergent and sequential synthesis designs: implications for conducting and reporting systematic reviews of qualitative and quantitative evidence.

PubMed

Hong, Quan Nha; Pluye, Pierre; Bujold, Mathieu; Wassef, Maggy

2017-03-23

Systematic reviews of qualitative and quantitative evidence can provide a rich understanding of complex phenomena. This type of review is increasingly popular, has been used to provide a landscape of existing knowledge, and addresses the types of questions not usually covered in reviews relying solely on either quantitative or qualitative evidence. Although several typologies of synthesis designs have been developed, none have been tested on a large sample of reviews. The aim of this review of reviews was to identify and develop a typology of synthesis designs and methods that have been used and to propose strategies for synthesizing qualitative and quantitative evidence. A review of systematic reviews combining qualitative and quantitative evidence was performed. Six databases were searched from inception to December 2014. Reviews were included if they were systematic reviews combining qualitative and quantitative evidence. The included reviews were analyzed according to three concepts of synthesis processes: (a) synthesis methods, (b) sequence of data synthesis, and (c) integration of data and synthesis results. A total of 459 reviews were included. The analysis of this literature highlighted a lack of transparency in reporting how evidence was synthesized and a lack of consistency in the terminology used. Two main types of synthesis designs were identified: convergent and sequential synthesis designs. Within the convergent synthesis design, three subtypes were found: (a) data-based convergent synthesis design, where qualitative and quantitative evidence is analyzed together using the same synthesis method, (b) results-based convergent synthesis design, where qualitative and quantitative evidence is analyzed separately using different synthesis methods and results of both syntheses are integrated during a final synthesis, and (c) parallel-results convergent synthesis design consisting of independent syntheses of qualitative and quantitative evidence and an interpretation of the results in the discussion. Performing systematic reviews of qualitative and quantitative evidence is challenging because of the multiple synthesis options. The findings provide guidance on how to combine qualitative and quantitative evidence. Also, recommendations are made to improve the conducting and reporting of this type of review.

Method for the rapid synthesis of large quantities of metal oxide nanowires at low temperatures

DOEpatents

Sunkara, Mahendra Kumar [Louisville, KY; Vaddiraju, Sreeram [Mountain View, CA; Mozetic, Miran [Ljubljan, SI; Cvelbar, Uros [Idrija, SI

2009-09-22

A process for the rapid synthesis of metal oxide nanoparticles at low temperatures and methods which facilitate the fabrication of long metal oxide nanowires. The method is based on treatment of metals with oxygen plasma. Using oxygen plasma at low temperatures allows for rapid growth unlike other synthesis methods where nanomaterials take a long time to grow. Density of neutral oxygen atoms in plasma is a controlling factor for the yield of nanowires. The oxygen atom density window differs for different materials. By selecting the optimal oxygen atom density for various materials the yield can be maximized for nanowire synthesis of the metal.

Subsurface attenuation estimation using a novel hybrid method based on FWE function and power spectrum

NASA Astrophysics Data System (ADS)

Li, Jingnan; Wang, Shangxu; Yang, Dengfeng; Tang, Genyang; Chen, Yangkang

2018-02-01

Seismic waves propagating in the subsurface suffer from attenuation, which can be represented by the quality factor Q. Knowledge of Q plays a vital role in hydrocarbon exploration. Many methods to measure Q have been proposed, among which the central frequency shift (CFS) and the peak frequency shift (PFS) are commonly used. However, both methods are under the assumption of a particular shape for amplitude spectra, which will cause systematic error in Q estimation. Recently a new method to estimate Q has been proposed to overcome this disadvantage by using frequency weighted exponential (FWE) function to fit amplitude spectra of different shapes. In the FWE method, a key procedure is to calculate the central frequency and variance of the amplitude spectrum. However, the amplitude spectrum is susceptible to noise, whereas the power spectrum is less sensitive to random noise and has better anti-noise performance. To enhance the robustness of the FWE method, we propose a novel hybrid method by combining the advantage of the FWE method and the power spectrum, which is called the improved FWE method (IFWE). The basic idea is to consider the attenuation of the power spectrum instead of the amplitude spectrum and to use a modified FWE function to fit power spectra, according to which we derive a new Q estimation formula. Tests of noisy synthetic data show that the IFWE are more robust than the FWE. Moreover, the frequency bandwidth selection in the IFWE can be more flexible than that in the FWE. The application to field vertical seismic profile data and surface seismic data further demonstrates its validity.

Green synthesis, characterization and antibacterial efficacy of palladium nanoparticles synthesized using Filicium decipiens leaf extract

NASA Astrophysics Data System (ADS)

Sharmila, G.; Farzana Fathima, M.; Haries, S.; Geetha, S.; Manoj Kumar, N.; Muthukumaran, C.

2017-06-01

Synthesis of metal nanoparticles through green chemistry route is an emerging eco-friendly approach in the present days. An eco-friendly, biogenic synthesis of palladium nanoparticles (PdNPs) using Filicium decipiens leaf extract was reported in the present study. The synthesized PdNPs were characterized by UV-visible spectroscopy, Transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The PdNPs formation was confirmed by UV-visible spectrophotometer and spherical shaped PdNPs with size range of 2-22 nm was observed in TEM analysis. Energy dispersive X-ray spectroscopy (EDS) analysis confirmed the presence of palladium in the synthesized nanoparticles. The crystalline nature of PdNPs was confirmed by XRD pattern and compared with the standard. The phytochemicals and proteins were identified by their functional groups in FT-IR spectrum and revealed the amide, amine groups present in F. decipiens may have involved in the bio-reduction reaction for PdNPs synthesis. Prepared PdNPs showed potential antibacterial activity against both Gram-positive and Gram-negative bacteria. F. decipiens leaf extract based PdNPs showed high bactericidal activity against Escherichia coli, Pseudomonas aeruginosa as compared to Staphylococcus aureus and Bacillus subtilis Results showed that phytochemicals rich F. decipiens leaf extract may be utilized as an effective non-toxic reducing agent for PdNPs synthesis and prepared PdNPs may useful in biomedical applications.

Synthesis of gold and silver nanoparticles using purified URAK.

PubMed

Deepak, Venkataraman; Umamaheshwaran, Paneer Selvam; Guhan, Kandasamy; Nanthini, Raja Amrisa; Krithiga, Bhaskar; Jaithoon, Nagoor Meeran Hasika; Gurunathan, Sangiliyandi

2011-09-01

This study aims at developing a new eco-friendly process for the synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using purified URAK. URAK is a fibrinolytic enzyme produced by Bacillus cereus NK1. The enzyme was purified and used for the synthesis of AuNPs and AgNPs. The enzyme produced AgNPs when incubated with 1 mM AgNO3 for 24 h and AuNPs when incubated with 1 mM HAuCl4 for 60 h. But when NaOH was added, the synthesis was rapid and occurred within 5 min for AgNPs and 12 h for AuNPs. The synthesized nanoparticles were characterized by a peak at 440 nm and 550 nm in the UV-visible spectrum. TEM analysis showed that AgNPs of the size 60 nm and AuNPs of size 20 nm were synthesized. XRD confirmed the crystalline nature of the nanoparticles and AFM showed the morphology of the nanoparticle to be spherical. FT-IR showed that protein was responsible for the synthesis of the nanoparticles. This process is highly simple, versatile and produces AgNPs and AuNPs in environmental friendly manner. Moreover, the synthesized nanoparticles were found to contain immobilized enzyme. Also, URAK was tested on RAW 264.7 macrophage cell line and was found to be non-cytotoxic until 100 μg/ml. Copyright © 2011 Elsevier B.V. All rights reserved.

Text-in-context: a method for extracting findings in mixed-methods mixed research synthesis studies.

PubMed

Sandelowski, Margarete; Leeman, Jennifer; Knafl, Kathleen; Crandell, Jamie L

2013-06-01

Our purpose in this paper is to propose a new method for extracting findings from research reports included in mixed-methods mixed research synthesis studies. International initiatives in the domains of systematic review and evidence synthesis have been focused on broadening the conceptualization of evidence, increased methodological inclusiveness and the production of evidence syntheses that will be accessible to and usable by a wider range of consumers. Initiatives in the general mixed-methods research field have been focused on developing truly integrative approaches to data analysis and interpretation. The data extraction challenges described here were encountered, and the method proposed for addressing these challenges was developed, in the first year of the ongoing (2011-2016) study: Mixed-Methods Synthesis of Research on Childhood Chronic Conditions and Family. To preserve the text-in-context of findings in research reports, we describe a method whereby findings are transformed into portable statements that anchor results to relevant information about sample, source of information, time, comparative reference point, magnitude and significance and study-specific conceptions of phenomena. The data extraction method featured here was developed specifically to accommodate mixed-methods mixed research synthesis studies conducted in nursing and other health sciences, but reviewers might find it useful in other kinds of research synthesis studies. This data extraction method itself constitutes a type of integration to preserve the methodological context of findings when statements are read individually and in comparison to each other. © 2012 Blackwell Publishing Ltd.

Play-Based Interventions for Children and Adolescents with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Gallo-Lopez, Loretta, Ed.; Rubin, Lawrence C., Ed.

2012-01-01

"Play-Based Interventions for Children and Adolescents with Autism Spectrum Disorders" explores the most recognized, researched, and practical methods for using play therapy with the increasing number of children diagnosed with Autism Spectrum Disorders (ASDs), and shows clinicians how to integrate these methods into their practices. Using a…

Ultrasound assisted sonochemical synthesis of samarium doped Y2O3 nanostructures for display applications

NASA Astrophysics Data System (ADS)

Venkatachalaiah, K. N.; Nagabhushana, H.; Basavaraj, R. B.; Venkataravanappa, M.; Suresh, C.

2018-04-01

Sm3+ doped (1-11 mol %) cubic Y2O3 nanoflowers were fabricated by simple low temperature Sonochemical method using Aloe Vera gel as fuel. The product was characterized by PXRD, SEM, TEM, DRS, PL etc. The powder X-ray diffraction (PXRD) profiles of nanophosphors showed cubic phase structure. The particle size was further confirmed by transmission electron microscope (TEM) and it was found to be in the range of 17-25 nm. The PL emission results reveal that the phosphor nanoparticles (NPs) emit an intensive yellowish light under 367 nm excitation. The excitation spectrum of Y2O3: Sm3+ (5 mol %) obtained by monitoring the emission of the 4f - 4f (4G5/2→6H7/2) transition of Sm3+ at 612 nm As can be seen that the excitation spectrum consists of strong band at 332 nm and a broad band centered at 367 nm which corresponds to host absorption, confirming the effective energy transfer from Y2O3 host to Sm3+ ions. In the present study, CIE and CCT were estimated and found to be (0.45688, 0.51727) and the CCT of Y2O3: Sm3+ at 367 nm excitation was found to be 3357 K which was within the range of vertical daylight. Thus it can be useful for artificial production of illumination devices.

Characterization of oxygen defects in diamond by means of density functional theory calculations

NASA Astrophysics Data System (ADS)

Thiering, Gergő; Gali, Adam

2016-09-01

Point defects in diamond are of high interest as candidates for realizing solid state quantum bits, bioimaging agents, or ultrasensitive electric or magnetic field sensors. Various artificial diamond synthesis methods should introduce oxygen contamination in diamond, however, the incorporation of oxygen into diamond crystal and the nature of oxygen-related point defects are largely unknown. Oxygen may be potentially interesting as a source of quantum bits or it may interact with other point defects which are well established solid state qubits. Here we employ plane-wave supercell calculations within density functional theory, in order to characterize the electronic and magneto-optical properties of various oxygen-related defects. Besides the trivial single interstitial and substitutional oxygen defects we also consider their complexes with vacancies and hydrogen atoms. We find that oxygen defects are mostly electrically active and introduce highly correlated orbitals that pose a challenge for density functional theory modeling. Nevertheless, we are able to identify the fingerprints of substitutional oxygen defect, the oxygen-vacancy and oxygen-vacancy-hydrogen complexes in the electron paramagnetic resonance spectrum. We demonstrate that first principles calculations can predict the motional averaging of the electron paramagnetic resonance spectrum of defects that are subject to Jahn-Teller distortion. We show that the high-spin neutral oxygen-vacancy defect exhibits very fast nonradiative decay from its optical excited state that might hinder applying it as a qubit.

Convergence of Hippocampal Pathophysiology in Syngap+/- and Fmr1-/y Mice.

PubMed

Barnes, Stephanie A; Wijetunge, Lasani S; Jackson, Adam D; Katsanevaki, Danai; Osterweil, Emily K; Komiyama, Noboru H; Grant, Seth G N; Bear, Mark F; Nägerl, U Valentin; Kind, Peter C; Wyllie, David J A

2015-11-11

Previous studies have hypothesized that diverse genetic causes of intellectual disability (ID) and autism spectrum disorders (ASDs) converge on common cellular pathways. Testing this hypothesis requires detailed phenotypic analyses of animal models with genetic mutations that accurately reflect those seen in the human condition (i.e., have structural validity) and which produce phenotypes that mirror ID/ASDs (i.e., have face validity). We show that SynGAP haploinsufficiency, which causes ID with co-occurring ASD in humans, mimics and occludes the synaptic pathophysiology associated with deletion of the Fmr1 gene. Syngap(+/-) and Fmr1(-/y) mice show increases in basal protein synthesis and metabotropic glutamate receptor (mGluR)-dependent long-term depression that, unlike in their wild-type controls, is independent of new protein synthesis. Basal levels of phosphorylated ERK1/2 are also elevated in Syngap(+/-) hippocampal slices. Super-resolution microscopy reveals that Syngap(+/-) and Fmr1(-/y) mice show nanoscale alterations in dendritic spine morphology that predict an increase in biochemical compartmentalization. Finally, increased basal protein synthesis is rescued by negative regulators of the mGlu subtype 5 receptor and the Ras-ERK1/2 pathway, indicating that therapeutic interventions for fragile X syndrome may benefit patients with SYNGAP1 haploinsufficiency. As the genetics of intellectual disability (ID) and autism spectrum disorders (ASDs) are unraveled, a key issue is whether genetically divergent forms of these disorders converge on common biochemical/cellular pathways and hence may be amenable to common therapeutic interventions. This study compares the pathophysiology associated with the loss of fragile X mental retardation protein (FMRP) and haploinsufficiency of synaptic GTPase-activating protein (SynGAP), two prevalent monogenic forms of ID. We show that Syngap(+/-) mice phenocopy Fmr1(-/y) mice in the alterations in mGluR-dependent long-term depression, basal protein synthesis, and dendritic spine morphology. Deficits in basal protein synthesis can be rescued by pharmacological interventions that reduce the mGlu5 receptor-ERK1/2 signaling pathway, which also rescues the same deficit in Fmr1(-/y) mice. Our findings support the hypothesis that phenotypes associated with genetically diverse forms of ID/ASDs result from alterations in common cellular/biochemical pathways. Copyright © 2015 Barnes et al.

Research on response spectrum of dam based on scenario earthquake

NASA Astrophysics Data System (ADS)

Zhang, Xiaoliang; Zhang, Yushan

2017-10-01

Taking a large hydropower station as an example, the response spectrum based on scenario earthquake is determined. Firstly, the potential source of greatest contribution to the site is determined on the basis of the results of probabilistic seismic hazard analysis (PSHA). Secondly, the magnitude and epicentral distance of the scenario earthquake are calculated according to the main faults and historical earthquake of the potential seismic source zone. Finally, the response spectrum of scenario earthquake is calculated using the Next Generation Attenuation (NGA) relations. The response spectrum based on scenario earthquake method is less than the probability-consistent response spectrum obtained by PSHA method. The empirical analysis shows that the response spectrum of scenario earthquake considers the probability level and the structural factors, and combines the advantages of the deterministic and probabilistic seismic hazard analysis methods. It is easy for people to accept and provide basis for seismic engineering of hydraulic engineering.

μ+SR Study on Layered Chromium Perovskites: Srn+1CrnO3n+1 (n = 1-3)

NASA Astrophysics Data System (ADS)

Nozaki, Hiroshi; Sakurai, Hiroya; Umegaki, Izumi; Ansaldo, Eduardo J.; Morris, Gerald D.; Hitti, Bassam; Arseneau, Donald J.; Andreica, Daniel; Amato, Alex; Månsson, Martin; Sugiyama, Jun

The magnetic nature of layered chromium perovskites, Srn+1CrnO3n+1 (n = 1-3) was studied by μ+SR using powder samples prepared by a high pressure synthesis technique. According to the weak transverse field measurements, each sample entered a magnetically ordered state below 110, 200, and 90 K for the n = 1, 2, and 3 samples, respectively. Zero field (ZF) spectra below the transition temperature exhibited a clear oscillation due to the formation of quasi-static magnetic order. The Fourier transform frequency-spectrum for the ZF time-spectrum indicated the existence of the multiple oscillation components. The frequencies for the multiple oscillatory signals showed a complex temperature dependence, implying the occurrence of structural change/transitions below TN.

Determination of the light ion abundances in the strong-helium star HR 3089

NASA Technical Reports Server (NTRS)

Lester, J. B.

1975-01-01

Using line blanketed model stellar atmospheres and a spectrum synthesis approach, a differential abundance study of the ultraviolet spectrum of HR 3089 relative to the normal star lambda Sco was performed. Both stars were found to have the same abundances of carbon and silicon, but the helium and nitrogen are significantly enhanced in HR 3089. The atmospheric parameters and the distribution of abundances found for HR 3089 agree well with the results of Osmer and Peterson on sharp-lined helium-rich stars. The rotational velocity of 160 km/sec found for HR 3089 places a constraint on the role of diffusion in producing the abundance anomalies. Examination of the resonance lines of C II, N II, Si III and Si IV shows no evidence for mass loss in either star.

The Relationship between Autism Spectrum Disorder and Melatonin during Fetal Development.

PubMed

Jin, Yunho; Choi, Jeonghyun; Won, Jinyoung; Hong, Yonggeun

2018-01-18

The aim of this review is to clarify the interrelationship between melatonin and autism spectrum disorder (ASD) during fetal development. ASD refers to a diverse range of neurodevelopmental disorders characterized by social deficits, impaired communication, and stereotyped or repetitive behaviors. Melatonin, which is secreted by the pineal gland, has well-established neuroprotective and circadian entraining effects. During pregnancy, the hormone crosses the placenta into the fetal circulation and transmits photoperiodic information to the fetus allowing the establishment of normal sleep patterns and circadian rhythms that are essential for normal neurodevelopment. Melatonin synthesis is frequently impaired in patients with ASD. The hormone reduces oxidative stress, which is harmful to the central nervous system. Therefore, the neuroprotective and circadian entraining roles of melatonin may reduce the risk of neurodevelopmental disorders such as ASD.

Bis-pyridinium quadrupolar derivatives. High Stokes shift selective probes for bio-imaging

NASA Astrophysics Data System (ADS)

Salice, Patrizio; Versari, Silvia; Bradamante, Silvia; Meinardi, Francesco; Macchi, Giorgio; Pagani, Giorgio A.; Beverina, Luca

2013-11-01

We describe the design, synthesis and characterization of five high Stokes shift quadrupolar heteroaryl compounds suitable as fluorescent probes in bio-imaging. In particular, we characterize the photophysical properties and the intracellular localization in Human Umbilical Vein Endothelial Cells (HUVEC) and Human Mesenchymal Stem Cells (HMSCs) for each dye. We show that, amongst all of the investigated derivatives, the 2,5-bis[1-(4-N-methylpyridinium)ethen-2-yl)]- N-methylpyrrole salt is the best candidates as selective mitochondrial tracker. Finally, we recorded the full emission spectrum of the most performing - exclusively mitochondrial selective - fluorescent probe directly from HUVEC stained cells. The emission spectrum collected from the stained mitochondria shows a remarkably more pronounced vibronic structure with respect to the emission of the free fluorophore in solution.

Multifrequency observations of a solar microwave burst with two-dimensional spatial resolution

NASA Technical Reports Server (NTRS)

Gary, Dale E.; Hurford, G. J.

1990-01-01

Frequency-agile interferometry observations using three baselines and the technique of frequency synthesis were used to obtain two-dimensional positions of multiple microwave sources at several frequency ranges in a solar flare. Source size and brightness temperature spectra were obtained near the peak of the burst. The size spectrum shows that the source size decreases rapidly with increasing frequency, but the brightness temperature spectrum can be well-fitted by gyrosynchrotron emission from a nonthermal distribution of electrons with power-law index of 4.8. The spatial structure of the burst showed several characteristics in common with primary/secondary bursts discussed by Nakajima et al. (1985). A source of coherent plasma emission at low frequencies is found near the secondary gyrosynchrotron source, associated with the leader spots of the active region.

Bioreduction potentials of dried root of Zingiber officinale for a simple green synthesis of silver nanoparticles: Antibacterial studies.

PubMed

Judith Vijaya, J; Jayaprakash, N; Kombaiah, K; Kaviyarasu, K; John Kennedy, L; Jothi Ramalingam, R; Al-Lohedan, Hamad A; V M, Mansoor-Ali; Maaza, M

2017-12-01

Green synthesis of silver nanoparticles (Ag NPs) using an extract of dried Zingiber officinale (ginger) root as a reducing and capping agent in the presence of microwave irradiation was herein reported for the first time. The formation of symmetrical spheres is confirmed from the UV-Visible spectrum of Ag NPs. Fourier transform infra-red spectroscopy confirms the formation of the Ag NPs. X-ray diffraction analysis was utilized to calculate the crystallite size of Ag NPs and the value was found to be 10nm. High-resolution transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the morphology and size of the synthesized samples. The sphere like morphology is confirmed from the images. The purity and crystallinity of Ag NPs is confirmed by energy-dispersive X-Ray analysis and selected area electron diffraction respectively. The electrochemical behavior of the synthesized Ag NPs was assessed by cyclic voltammetry (CV) and shows the redox peaks in the potential range of -1.1 to +1.1V. Agar diffusion method is used to examine the antibacterial activity of Ag NPs. For this purpose, two gram positive and two gram negative bacteria were studied. This single step approach was found to be simple, short time, cost-effective, reproducible, and eco-friendly. Copyright © 2017. Published by Elsevier B.V.

Pulsed plasma chemical synthesis of carbon-containing titanium and silicon oxide based nanocomposite

NASA Astrophysics Data System (ADS)

Kholodnaya, Galina; Sazonov, Roman; Ponomarev, Denis; Zhirkov, Igor

2018-03-01

The paper presents the results of the experimental investigation of the physical and chemical properties of the TixSiyCzOw composite nanopowders, which were first obtained using a pulsed plasma chemical method. The pulsed plasma chemical synthesis was achieved using a technological electron accelerator (TEA-500). The parameters of the electron beam are as follows: 400-450 keV electron energy, 60 ns half-amplitude pulse duration, up to 200 J pulse energy, and 5 cm beam diameter. The main physical and chemical properties of the obtained composites were studied (morphology, chemical, elemental and phase composition). The morphology of the TixSiyCzOw composites is multiform. There are large round particles, with an average size of above 150 nm. Besides, there are small particles (an average size is in the range of 15-40 nm). The morphology of small particles is in the form of crystallites. In the TixSiyCzOw synthesised composite, the peak with a maximum of 946 cm-1 was registered. The presence of IR radiation in this region of the spectrum is typical for the deformation of atomic oscillations in the Si‒О‒Ti bond, which indicates the formation of the solid solution. The composites consist of two crystal phases - anatase and rutile. The prevailing phase of the crystal structure is rutile.

One-pot synthesis and lubricity of fluorescent carbon dots applied on PCL-PEG-PCL hydrogel.

PubMed

Guo, Junde; Mei, Tangjie; Li, Yue; Hafezi, Mahshid; Lu, Hailin; Li, Jianhui; Dong, Guangneng

2018-06-12

This work presents a method for one-pot synthesis of N-doped nanometer-size carbon dots, which can be assembled with thermosensitive poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) hydrogel to achieve slow-release lubricity. The typical property of this green production was studied by fourier transform infrared (FT-IR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscope (TEM). The photoluminescence of composite PCEC/CDs hydrogel and its released solutions were characterized by ultraviolet spectrum, and the rheological properties were tested by rotary rheometer. Tribological performance of the released solution from composite PCEC/CDs hydrogel was obtained to compare with PBS and pure CDs solution. The experimental results reveal that the CDs contain the chemical groups of N-H, C-OH/C-O-C and -COOH, etc. In addition, the diameter of the CDs is in the range of 6~8 nm. The phase transition behavior of PCEC/CDs hydrogel can be still kept and its viscoelasticity hydrogel is improved by approximatively 7%. Furthermore, friction coefficient of the released solution from composite PCEC/CDs hydrogel decreases by about 70% than that of PBS. Besides, the wear condition can be improved by a lubricating transfer film formed by released CDs. This novel strategy for slow-release application is valuable for drug delivery and bio-tribology.

Chemically stabilized reduced graphene oxide/zirconia nanocomposite: synthesis and characterization

NASA Astrophysics Data System (ADS)

Sagadevan, Suresh; Zaman Chowdhury, Zaira; Enamul Hoque, Md; Podder, Jiban

2017-11-01

In this research, chemical method was used to fabricate reduced graphene oxide/zirconia (rGO/ZrO2) nanocomposite. X-ray Diffraction analysis (XRD) was carried out to examine the crystalline structure of the nanocomposites. The nanocomposite prepared here has average crystallite size of 14 nm. The surface morphology was observed using scanning electron microscopic analysis (SEM) coupled with electron dispersion spectroscopy (EDS) to detect the chemical element over the surface of the nanocomposites. High-resolution Transmission electron microscopic analysis (HR-TEM) was carried out to determine the particle size and shape of the nanocomposites. The optical property of the prepared samples was determined using UV-visible absorption spectrum. The functional groups were identified using FTIR and Raman spectroscopic analysis. Efficient, cost effective and properly optimized synthesis process of rGO/ZrO2 nanocomposite can ensure the presence of infiltrating graphene network inside the ZrO2 matrix to enhance the electrical properties of the hybrid composites up to a greater scale. Thus the dielectric constant, dielectric loss and AC conductivity of the prepared sample was measured at various frequencies and temperatures. The analytical results obtained here confirmed the homogeneous dispersion of ZrO2 nanostructures over the surface of reduced graphene oxide nanosheets. Overall, the research demonstrated that the rGO/ZrO2 nano-hybrid structure fabricated here can be considered as a promising candidate for applications in nanoelectronics and optoelectronics.

Evaluation of graphical and statistical representation of analytical signals of spectrophotometric methods

NASA Astrophysics Data System (ADS)

Lotfy, Hayam Mahmoud; Fayez, Yasmin Mohammed; Tawakkol, Shereen Mostafa; Fahmy, Nesma Mahmoud; Shehata, Mostafa Abd El-Atty

2017-09-01

Simultaneous determination of miconazole (MIC), mometasone furaoate (MF), and gentamicin (GEN) in their pharmaceutical combination. Gentamicin determination is based on derivatization with of o-phthalaldehyde reagent (OPA) without any interference of other cited drugs, while the spectra of MIC and MF are resolved using both successive and progressive resolution techniques. The first derivative spectrum of MF is measured using constant multiplication or spectrum subtraction, while its recovered zero order spectrum is obtained using derivative transformation. Beside the application of constant value method. Zero order spectrum of MIC is obtained by derivative transformation after getting its first derivative spectrum by derivative subtraction method. The novel method namely, differential amplitude modulation is used to get the concentration of MF and MIC, while the novel graphical method namely, concentration value is used to get the concentration of MIC, MF, and GEN. Accuracy and precision testing of the developed methods show good results. Specificity of the methods is ensured and is successfully applied for the analysis of pharmaceutical formulation of the three drugs in combination. ICH guidelines are used for validation of the proposed methods. Statistical data are calculated, and the results are satisfactory revealing no significant difference regarding accuracy and precision.

Study on Stationarity of Random Load Spectrum Based on the Special Road

NASA Astrophysics Data System (ADS)

Yan, Huawen; Zhang, Weigong; Wang, Dong

2017-09-01

In the special road quality assessment method, there is a method using a wheel force sensor, the essence of this method is collecting the load spectrum of the car to reflect the quality of road. According to the definition of stochastic process, it is easy to find that the load spectrum is a stochastic process. However, the analysis method and application range of different random processes are very different, especially in engineering practice, which will directly affect the design and development of the experiment. Therefore, determining the type of a random process has important practical significance. Based on the analysis of the digital characteristics of road load spectrum, this paper determines that the road load spectrum in this experiment belongs to a stationary stochastic process, paving the way for the follow-up modeling and feature extraction of the special road.

Bayesian data augmentation methods for the synthesis of qualitative and quantitative research findings

PubMed Central

Crandell, Jamie L.; Voils, Corrine I.; Chang, YunKyung; Sandelowski, Margarete

2010-01-01

The possible utility of Bayesian methods for the synthesis of qualitative and quantitative research has been repeatedly suggested but insufficiently investigated. In this project, we developed and used a Bayesian method for synthesis, with the goal of identifying factors that influence adherence to HIV medication regimens. We investigated the effect of 10 factors on adherence. Recognizing that not all factors were examined in all studies, we considered standard methods for dealing with missing data and chose a Bayesian data augmentation method. We were able to summarize, rank, and compare the effects of each of the 10 factors on medication adherence. This is a promising methodological development in the synthesis of qualitative and quantitative research. PMID:21572970

The controlled growth of perovskite thin films: Opportunities, challenges, and synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schlom, D.G.; Theis, C.D.; Hawley, M.E.

1997-10-01

The broad spectrum of electronic and optical properties exhibited by perovskites offers tremendous opportunities for microelectronic devices, especially when a combination of properties in a single device is desired. Molecular beam epitaxy (MBE) has achieved unparalleled control in the integration of semiconductors at the monolayer-level; its use for the integration of perovskites with similar nanoscale customization appears promising. Composition control and oxidation are often significant challenges to the growth of perovskites by MBE, but we show that these can be met through the use of purified ozone as an oxidant and real-time atomic absorption composition control. The opportunities, challenges, andmore » synthesis of oxide heterostructures by reactive MBE are described, with examples taken from the growth of oxide superconductors and oxide ferroelectrics.« less

Development and characterization of Mn2+-doped MgO nanoparticles by solution combustion synthesis

NASA Astrophysics Data System (ADS)

Basha, Md. Hussain; Gopal, N. O.; Rao, J. L.; Nagabhushana, H.; Nagabhushana, B. M.; Chakradhar, R. P. S.

2015-06-01

Mn doped MgO Nanoparticles have been prepared by Solution Combustion Synthesis. The synthesized sample is characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Electron Paramagnetic Resonance (EPR). The prepared MgO:Mn (1 mol%) nano crystals appear to be of simple cubic crystalline phase with lattice parameters a = 4.218(2) Å and cell volume = 74.98 (7) Å3. SEM micrograph of powders show highly porous, many agglomerates with irregular morphology, large voids, cracks and pores. EPR spectrum of the sample at room temperature exhibit an isotropic sextet hyperfine pattern, centered at g=1.99, characteristic if Mn2+ ions with S=I=5/2.The observed g value and the hyperfine value reveal the ionic bonding between Mn2+ and its surroundings.

Single step synthesis and organization of gold colloids assisted by copolymer templates

NASA Astrophysics Data System (ADS)

Sarrazin, Aurélien; Gontier, Arthur; Plaud, Alexandre; Béal, Jérémie; Yockell-Lelièvre, Hélène; Bijeon, Jean-Louis; Plain, Jérôme; Adam, Pierre-Michel; Maurer, Thomas

2014-06-01

We report here an original single-step process for the synthesis and self-organization of gold colloids by simply incorporating gold salts into a solution prepared using polystyrene (PS)-polymethylmethacrylate copolymer and thiolated PS with propylene glycol methyl ether acetate as a solvent. The spin-coating and annealing of this solution then allows the formation of PS domains. Depending on the polymer concentration of the as-prepared solution, there can be either one or several gold nanoparticles (Au NPs) per PS domain. For high concentrations of Au NPs in PS domains, the coupling between plasmonic NPs leads to the observation of a second peak in the optical extinction spectrum. Such a collective effect could be relevant for the development of optical strain sensors in the near future.

First report of biomimetic synthesis of silver nanoparticles using aqueous callus extract of Centella asiatica and their antimicrobial activity

NASA Astrophysics Data System (ADS)

Netala, Vasudeva Reddy; Kotakadi, Venkata Subbaiah; Nagam, Venkateswarlu; Bobbu, Pushpalatha; Ghosh, Sukhendu Bikash; Tartte, Vijaya

2015-10-01

The present study reports the simple and eco-friendly approach for biosynthesis of silver nanoparticles (AgNPs) using aqueous callus extract as reducing agent for the first time. The formation of AgNPs was initially confirmed by characteristic surface plasmon resonance (SPR) peak 453 nm by UV-Visible spectroscopy. FTIR spectrum shows different functional groups which probably involved in the synthesis and stabilization of AgNPs. TEM analysis determined the well-dispersed AgNPs with roughly spherical shape and size ranging 5-40 nm. XRD patterns revealed the crystalline nature of AgNPs with face-centered cubic (fcc) lattice. The synthesized AgNPs were found to have strong inhibitory activity against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa.

New target for inhibition of bacterial RNA polymerase: 'switch region'.

PubMed

Srivastava, Aashish; Talaue, Meliza; Liu, Shuang; Degen, David; Ebright, Richard Y; Sineva, Elena; Chakraborty, Anirban; Druzhinin, Sergey Y; Chatterjee, Sujoy; Mukhopadhyay, Jayanta; Ebright, Yon W; Zozula, Alex; Shen, Juan; Sengupta, Sonali; Niedfeldt, Rui Rong; Xin, Cai; Kaneko, Takushi; Irschik, Herbert; Jansen, Rolf; Donadio, Stefano; Connell, Nancy; Ebright, Richard H

2011-10-01

A new drug target - the 'switch region' - has been identified within bacterial RNA polymerase (RNAP), the enzyme that mediates bacterial RNA synthesis. The new target serves as the binding site for compounds that inhibit bacterial RNA synthesis and kill bacteria. Since the new target is present in most bacterial species, compounds that bind to the new target are active against a broad spectrum of bacterial species. Since the new target is different from targets of other antibacterial agents, compounds that bind to the new target are not cross-resistant with other antibacterial agents. Four antibiotics that function through the new target have been identified: myxopyronin, corallopyronin, ripostatin, and lipiarmycin. This review summarizes the switch region, switch-region inhibitors, and implications for antibacterial drug discovery. Copyright © 2011 Elsevier Ltd. All rights reserved.

β-thalassemias: paradigmatic diseases for scientific discoveries and development of innovative therapies.

PubMed

Rivella, Stefano

2015-04-01

β-thalassemias are monogenic disorders characterized by defective synthesis of the β-globin chain, one of the major components of adult hemoglobin. A large number of mutations in the β-globin gene or its regulatory elements have been associated with β-thalassemias. Due to the complexity of the regulation of the β-globin gene and the role of red cells in many physiological processes, patients can manifest a large spectrum of phenotypes, and clinical requirements vary from patient to patient. It is important to consider the major differences in the light of potential novel therapeutics. This review summarizes the main discoveries and mechanisms associated with the synthesis of β-globin and abnormal erythropoiesis, as well as current and novel therapies. Copyright© Ferrata Storti Foundation.

How do Parents Manage Irritability, Challenging Behaviour, Non-Compliance and Anxiety in Children with Autism Spectrum Disorders? A Meta-Synthesis.

PubMed

O'Nions, Elizabeth; Happé, Francesca; Evers, Kris; Boonen, Hannah; Noens, Ilse

2018-04-01

Although there is increasing research interest in the parenting of children with ASD, at present, little is known about everyday strategies used to manage problem behaviour. We conducted a meta-synthesis to explore what strategies parents use to manage irritability, non-compliance, challenging behaviour and anxiety in their children with ASD. Approaches included: (1) accommodating the child; (2) modifying the environment; (3) providing structure, routine and occupation; (4) supervision and monitoring; (5) managing non-compliance with everyday tasks; (6) responding to problem behaviour; (7) managing distress; (8) maintaining safety and (9) analysing and planning. Results suggest complex parenting demands in children with ASD and problem behaviour. Findings will inform the development of a new measure to quantify parenting strategies relevant to ASD.

Cascade multicomponent synthesis of indoles, pyrazoles, and pyridazinones by functionalization of alkenes.

PubMed

Matcha, Kiran; Antonchick, Andrey P

2014-10-27

The development of multicomponent reactions for indole synthesis is demanding and has hardly been explored. The present study describes the development of a novel multicomponent, cascade approach for indole synthesis. Various substituted indole derivatives were obtained from simple reagents, such as unfunctionalized alkenes, diazonium salts, and sodium triflinate, by using an established straightforward and regioselective method. The method is based on the radical trifluoromethylation of alkenes as an entry into Fischer indole synthesis. Besides indole synthesis, the application of the multicomponent cascade reaction to the synthesis of pyrazoles and pyridazinones is described. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engineering calculations for communications satellite systems planning

NASA Technical Reports Server (NTRS)

Walton, E.; Aebker, E.; Mata, F.; Reilly, C.

1991-01-01

The final phase of a satellite synthesis project is described. Several methods for generating satellite positionings with improved aggregate carrier to interference characteristics were studied. Two general methods for modifying required separation values are presented. Also, two methods for improving aggregate carrier to interference (C/I) performance of given satellite synthesis solutions are presented. A perturbation of the World Administrative Radio Conference (WARC) synthesis is presented.

Recent progress in chemical and chemoenzymatic synthesis of carbohydrates.

PubMed

Muthana, Saddam; Cao, Hongzhi; Chen, Xi

2009-12-01

The important roles that carbohydrates play in biological processes and their potential application in diagnosis, therapeutics, and vaccine development have made them attractive synthetic targets. Despite ongoing challenges, tremendous progresses have been made in recent years for the synthesis of carbohydrates. The chemical glycosylation methods have become more sophisticated and the synthesis of oligosaccharides has become more predictable. Simplified one-pot glycosylation strategy and automated synthesis are increasingly used to obtain biologically important glycans. On the other hand, chemoenzymatic synthesis continues to be a powerful alternative for obtaining complex carbohydrates. This review highlights recent progress in chemical and chemoenzymatic synthesis of carbohydrates with a particular focus on the methods developed for the synthesis of oligosaccharides, polysaccharides, glycolipids, and glycosylated natural products.

Recent Progress in Chemical and Chemoenzymatic Synthesis of Carbohydrates

PubMed Central

Muthana, Saddam; Cao, Hongzhi; Chen, Xi

2011-01-01

Summary The important roles that carbohydrates play in biological processes and their potential application in diagnosis, therapeutics, and vaccine development have made them attractive synthetic targets. Despite ongoing challenges, tremendous progresses have been made in recent years for the synthesis of carbohydrates. The chemical glycosylation methods have become more sophisticated and the synthesis of oligosaccharides has become more predictable. Simplified one-pot glycosylation strategy and automated synthesis are increasingly used to obtain biologically important glycans. On the other hand, chemoenzymatic synthesis continues to be a powerful alternative for obtaining complex carbohydrates. This review highlights recent progress in chemical and chemoenzymatic synthesis of carbohydrates with a particular focus on the methods developed for the synthesis of oligosaccharides, polysaccharides, glycolipids, and glycosylated natural products. PMID:19833544

VizieR Online Data Catalog: RV of candidate hybrid variable stars (Lampens+, 2018)

NASA Astrophysics Data System (ADS)

Lampens, P.; Fremat, Y.; Vermeylen, L.; Sodor, A.; Skarka, M.; De Cat, P.; Bognar, Zs.; de Nutte, R.; Dumortier, L.; Escorza, A.; Oomen, G. M.; van de Steene, G.; Kamath, D.; Laverick, M.; Samadi, A.; Triana, S.; Lehmann, H.

2017-09-01

We present the individual radial velocity measurements of 50 candidate delta Scuti - gamma Doradus hybrid stars and one delta Scuti star from the Kepler mission collected with the Hermes and Ace spectrographs over a time span of months to years. The radial velocities were measured using spectrum synthesis and a two-dimensional cross-correlation technique in the case of double- and triple-lined systems. (5 data files).

Obsessive-compulsive disorder and related disorders: a comprehensive survey

PubMed Central

Fornaro, Michele; Gabrielli, Filippo; Albano, Claudio; Fornaro, Stefania; Rizzato, Salvatore; Mattei, Chiara; Solano, Paola; Vinciguerra, Valentina; Fornaro, Pantaleo

2009-01-01

Our aim was to present a comprehensive, updated survey on obsessive-compulsive disorder (OCD) and obsessive-compulsive related disorders (OCRDs) and their clinical management via literature review, critical analysis and synthesis. Information on OCD and OCRD current nosography, clinical phenomenology and etiology, may lead to a better comprehension of their management. Clinicians should become familiar with the broad spectrum of OCD disorders, since it is a pivotal issue in current clinical psychiatry. PMID:19450269

Treatment of Early-Onset Schizophrenia Spectrum Disorders (TEOSS): Rationale, Design, and Methods

ERIC Educational Resources Information Center

McClellan, Jon; Sikich, Linmarie; Findling, Robert L.; Frazier, Jean A.; Vitiello, Benedetto; Hlastala, Stefanie A.; Williams, Emily; Ambler, Denisse; Hunt-Harrison, Tyehimba; Maloney, Ann E.; Ritz, Louise; Anderson, Robert; Hamer, Robert M.; Lieberman, Jeffrey A.

2007-01-01

Objective: The Treatment of Early Onset Schizophrenia Spectrum Disorders Study is a publicly funded clinical trial designed to compare the therapeutic benefits, safety, and tolerability of risperidone, olanzapine, and molindone in youths with early-onset schizophrenia spectrum disorders. The rationale, design, and methods of the Treatment of Early…

Spectrum interrogation of fiber acoustic sensor based on self-fitting and differential method.

PubMed

Fu, Xin; Lu, Ping; Ni, Wenjun; Liao, Hao; Wang, Shun; Liu, Deming; Zhang, Jiangshan

2017-02-20

In this article, we propose an interrogation method of fiber acoustic sensor to recover the time-domain signal from the sensor spectrum. The optical spectrum of the sensor will show a ripple waveform when responding to acoustic signal due to the scanning process in a certain wavelength range. The reason behind this phenomenon is the dynamic variation of the sensor spectrum while the intensity of different wavelength is acquired at different time in a scanning period. The frequency components can be extracted from the ripple spectrum assisted by the wavelength scanning speed. The signal is able to be recovered by differential between the ripple spectrum and its self-fitted curve. The differential process can eliminate the interference caused by environmental perturbations such as temperature or refractive index (RI), etc. The proposed method is appropriate for fiber acoustic sensors based on gratings or interferometers. A long period grating (LPG) is adopted as an acoustic sensor head to prove the feasibility of the interrogation method in experiment. The ability to compensate the environmental fluctuations is also demonstrated.

Meta-synthesis of qualitative research: the challenges and opportunities.

PubMed

Mohammed, Mohammed A; Moles, Rebekah J; Chen, Timothy F

2016-06-01

Synthesis of qualitative studies is an emerging area that has been gaining more interest as an important source of evidence for improving health care policy and practice. In the last decade there have been numerous attempts to develop methods of aggregating and synthesizing qualitative data. Although numerous empirical qualitative studies have been published about different aspects of health care research, to date, the aggregation and syntheses of these data has not been commonly reported, particularly in pharmacy practice related research. This paper describes different methods of conducting meta-synthesis and provides an overview of selected common methods. The paper also emphasizes the challenges and opportunities associated with conducting meta-synthesis and highlights the importance of meta-synthesis in informing practice, policy and research.

Meta-Synthesis of Research on Information Seeking Behaviour

ERIC Educational Resources Information Center

Urquhart, Christine

2011-01-01

Introduction: Meta-synthesis methods may help to make more sense of information behaviour research evidence. Aims and objectives: The objectives are to: 1) identify and examine the theoretical research strategies commonly used in information behaviour research; 2) discuss meta-synthesis methods that might be appropriate to the type of research…

Synthesis of amino acids

DOEpatents

Davis, J.W. Jr.

1979-09-21

A method is described for synthesizing amino acids preceding through novel intermediates of the formulas: R/sub 1/R/sub 2/C(OSOC1)CN, R/sub 1/R/sub 2/C(C1)CN and (R/sub 1/R/sub 2/C(CN)O)/sub 2/SO wherein R/sub 1/ and R/sub 2/ are each selected from hydrogen and monovalent hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

Computational method and system for modeling, analyzing, and optimizing DNA amplification and synthesis

DOEpatents

Vandersall, Jennifer A.; Gardner, Shea N.; Clague, David S.

2010-05-04

A computational method and computer-based system of modeling DNA synthesis for the design and interpretation of PCR amplification, parallel DNA synthesis, and microarray chip analysis. The method and system include modules that address the bioinformatics, kinetics, and thermodynamics of DNA amplification and synthesis. Specifically, the steps of DNA selection, as well as the kinetics and thermodynamics of DNA hybridization and extensions, are addressed, which enable the optimization of the processing and the prediction of the products as a function of DNA sequence, mixing protocol, time, temperature and concentration of species.

Synthesis of alpha-amino acids

DOEpatents

Davis, Jr., Jefferson W.

1983-01-01

A method for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

Synthesis of alpha-amino acids

DOEpatents

Davis, J.W. Jr.

1983-01-25

A method is described for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R[sub 1]R[sub 2]C(OSOCl)CN, R[sub 1]R[sub 2]C(Cl)CN and [R[sub 1]R[sub 2]C(CN)O][sub 2]SO wherein R[sub 1] and R[sub 2] are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art. No Drawings

Synthesis of alpha-amino acids

DOEpatents

Davis, Jr., Jefferson W.

1983-01-01

A method for synthesizing alpha amino acids proceding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

The microwave-assisted ionic-liquid method: a promising methodology in nanomaterials.

PubMed

Ma, Ming-Guo; Zhu, Jie-Fang; Zhu, Ying-Jie; Sun, Run-Cang

2014-09-01

In recent years, the microwave-assisted ionic-liquid method has been accepted as a promising methodology for the preparation of nanomaterials and cellulose-based nanocomposites. Applications of this method in the preparation of cellulose-based nanocomposites comply with the major principles of green chemistry, that is, they use an environmentally friendly method in environmentally preferable solvents to make use of renewable materials. This minireview focuses on the recent development of the synthesis of nanomaterials and cellulose-based nanocomposites by means of the microwave-assisted ionic-liquid method. We first discuss the preparation of nanomaterials including noble metals, metal oxides, complex metal oxides, metal sulfides, and other nanomaterials by means of this method. Then we provide an overview of the synthesis of cellulose-based nanocomposites by using this method. The emphasis is on the synthesis, microstructure, and properties of nanostructured materials obtained through this methodology. Our recent research on nanomaterials and cellulose-based nanocomposites by this rapid method is summarized. In addition, the formation mechanisms involved in the microwave-assisted ionic-liquid synthesis of nanostructured materials are discussed briefly. Finally, the future perspectives of this methodology in the synthesis of nanostructured materials are proposed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonuniform fast Fourier transform method for numerical diffraction simulation on tilted planes.

PubMed

Xiao, Yu; Tang, Xiahui; Qin, Yingxiong; Peng, Hao; Wang, Wei; Zhong, Lijing

2016-10-01

The method, based on the rotation of the angular spectrum in the frequency domain, is generally used for the diffraction simulation between the tilted planes. Due to the rotation of the angular spectrum, the interval between the sampling points in the Fourier domain is not even. For the conventional fast Fourier transform (FFT)-based methods, a spectrum interpolation is needed to get the approximate sampling value on the equidistant sampling points. However, due to the numerical error caused by the spectrum interpolation, the calculation accuracy degrades very quickly as the rotation angle increases. Here, the diffraction propagation between the tilted planes is transformed into a problem about the discrete Fourier transform on the uneven sampling points, which can be evaluated effectively and precisely through the nonuniform fast Fourier transform method (NUFFT). The most important advantage of this method is that the conventional spectrum interpolation is avoided and the high calculation accuracy can be guaranteed for different rotation angles, even when the rotation angle is close to π/2. Also, its calculation efficiency is comparable with that of the conventional FFT-based methods. Numerical examples as well as a discussion about the calculation accuracy and the sampling method are presented.

Text-in-Context: A Method for Extracting Findings in Mixed-Methods Mixed Research Synthesis Studies

PubMed Central

Leeman, Jennifer; Knafl, Kathleen; Crandell, Jamie L.

2012-01-01

Aim Our purpose in this paper is to propose a new method for extracting findings from research reports included in mixed-methods mixed research synthesis studies. Background International initiatives in the domains of systematic review and evidence synthesis have been focused on broadening the conceptualization of evidence, increased methodological inclusiveness and the production of evidence syntheses that will be accessible to and usable by a wider range of consumers. Initiatives in the general mixed-methods research field have been focused on developing truly integrative approaches to data analysis and interpretation. Data source The data extraction challenges described here were encountered and the method proposed for addressing these challenges was developed, in the first year of the ongoing (2011–2016) study: Mixed-Methods Synthesis of Research on Childhood Chronic Conditions and Family. Discussion To preserve the text-in-context of findings in research reports, we describe a method whereby findings are transformed into portable statements that anchor results to relevant information about sample, source of information, time, comparative reference point, magnitude and significance and study-specific conceptions of phenomena. Implications for nursing The data extraction method featured here was developed specifically to accommodate mixed-methods mixed research synthesis studies conducted in nursing and other health sciences, but reviewers might find it useful in other kinds of research synthesis studies. Conclusion This data extraction method itself constitutes a type of integration to preserve the methodological context of findings when statements are read individually and in comparison to each other. PMID:22924808

Zinc Oxide Nanoparticles for Revolutionizing Agriculture: Synthesis and Applications

PubMed Central

Sabir, Sidra; Arshad, Muhammad

2014-01-01

Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles. PMID:25436235

Zinc oxide nanoparticles for revolutionizing agriculture: synthesis and applications.

PubMed

Sabir, Sidra; Arshad, Muhammad; Chaudhari, Sunbal Khalil

2014-01-01

Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles.

The synthesis method for design of electron flow sources

NASA Astrophysics Data System (ADS)

Alexahin, Yu I.; Molodozhenzev, A. Yu

1997-01-01

The synthesis method to design a relativistic magnetically - focused beam source is described in this paper. It allows to find a shape of electrodes necessary to produce laminar space charge flows. Electron guns with shielded cathodes designed with this method were analyzed using the EGUN code. The obtained results have shown the coincidence of the synthesis and analysis calculations [1]. This method of electron gun calculation may be applied for immersed electron flows - of interest for the EBIS electron gun design.

Synthesis of neutral ether lipid monoalkyl-diacylglycerol by lipid acyltransferases[S

PubMed Central

Ma, Zhengping; Onorato, Joelle M.; Chen, Luping; Nelson, David W.; Yen, Chi-Liang Eric; Cheng, Dong

2017-01-01

In mammals, ether lipids exert a wide spectrum of signaling and structural functions, such as stimulation of immune responses, anti-tumor activities, and enhancement of sperm functions. Abnormal accumulation of monoalkyl-diacylglycerol (MADAG) was found in Wolman’s disease, a human genetic disorder defined by a deficiency in lysosomal acid lipase. In the current study, we found that among the nine recombinant human lipid acyltransferases examined, acyl-CoA:diacylglycerol acyltransferase (DGAT)1, DGAT2, acyl-CoA:monoacylglycerol acyltransferase (MGAT)2, MGAT3, acyl-CoA:wax-alcohol acyltransferase 2/MFAT, and DGAT candidate 3 were able to use 1-monoalkylglycerol (1-MAkG) as an acyl acceptor for the synthesis of monoalkyl-monoacylglycerol (MAMAG). These enzymes demonstrated different enzymatic turnover rates and relative efficiencies for the first and second acylation steps leading to the synthesis of MAMAG and MADAG, respectively. They also exhibited different degrees of substrate preference when presented with 1-monooleoylglycerol versus 1-MAkG. In CHO-K1 cells, treatment with DGAT1 selective inhibitor, XP-620, completely blocked the synthesis of MADAG, indicating that DGAT1 is the predominant enzyme responsible for the intracellular synthesis of MADAG in this model system. The levels of MADAG in the adrenal gland of DGAT1 KO mice were reduced as compared with those of the WT mice, suggesting that DGAT1 is a major enzyme for the synthesis of MADAG in this tissue. Our findings indicate that several of these lipid acyltransferases may be able to synthesize neutral ether lipids in mammals. PMID:28420705

Mutation screening of melatonin-related genes in patients with autism spectrum disorders.

PubMed

Jonsson, Lina; Ljunggren, Elin; Bremer, Anna; Pedersen, Christin; Landén, Mikael; Thuresson, Kent; Giacobini, Maibritt; Melke, Jonas

2010-04-08

One consistent finding in autism spectrum disorders (ASD) is a decreased level of the pineal gland hormone melatonin and it has recently been demonstrated that this decrease to a large extent is due to low activity of the acetylserotonin O-methyltransferase (ASMT), the last enzyme in the melatonin synthesis pathway. Moreover, mutations in the ASMT gene have been identified, including a splice site mutation, that were associated with low ASMT activity and melatonin secretion, suggesting that the low ASMT activity observed in autism is, at least partly, due to variation within the ASMT gene. In the present study, we have investigated all the genes involved in the melatonin pathway by mutation screening of AA-NAT (arylalkylamine N-acetyltransferase), ASMT, MTNR1A, MTNR1B (melatonin receptor 1A and 1B) and GPR50 (G protein-coupled receptor 50), encoding both synthesis enzymes and the three main receptors of melatonin, in 109 patients with autism spectrum disorders (ASD). A cohort of 188 subjects from the general population was used as a comparison group and was genotyped for the variants identified in the patient sample. Several rare variants were identified in patients with ASD, including the previously reported splice site mutation in ASMT (IVS5+2T>C). Of the variants affecting protein sequence, only the V124I in the MTNR1B gene was absent in our comparison group. However, mutations were found in upstream regulatory regions in three of the genes investigated, ASMT, MTNR1A, and MTNR1B. Our report of another ASD patient carrying the splice site mutation IVS5+2T>C, in ASMT further supports an involvement of this gene in autism. Moreover, our results also suggest that other melatonin related genes might be interesting candidates for further investigation in the search for genes involved in autism spectrum disorders and related neurobehavioral phenotypes. However, further studies of the novel variants identified in this study are warranted to shed light on their potential role in the pathophysiology of these disorders.

Synthesis of monodispersed ZnAl{sub 2}O{sub 4} nanoparticles and their tribology properties as lubricant additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Xiaoyun; Zheng, Shaohua; Zhang, Jun

Graphical abstract: Display Omitted Highlights: ► The preparation of ZnAl{sub 2}O{sub 4} nanoparticles was realized by hydrothermal method. ► After surface modification, ZnAl{sub 2}O{sub 4} nanoparticles of narrow size distribution can disperse in lubricating oil stably. ► The modified ZnAl{sub 2}O{sub 4} nanoparticles as lubricating oil additives exhibit good tribology properties. -- Abstract: Monodispersed spherical zinc aluminate spinel (ZnAl{sub 2}O{sub 4}) nanoparticles were synthesized via a solvothermal method and modified by oleic acid in cyclohexanol solution. The nanoparticles were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and infrared spectrum (IR). The dispersion ability of nanoparticles in lubricant oilmore » was measured with optical absorbance spectrum. The results show that the modified nanoparticles are nearly monodispersed and can stably disperse in lubricant oil. The tribological properties of the ZnAl{sub 2}O{sub 4} nanoparticles as an additive in lubricant oil were evaluated with four-ball test and thrust-ring test. For comparison, ZnO and Al{sub 2}O{sub 3} nanoparticles as additive in lubricant oil were also tested respectively. The results show that ZnAl{sub 2}O{sub 4} nanoparticles exhibit better tribology properties in terms of anti-wear and anti-friction than ZnO or Al{sub 2}O{sub 3} nanoparticles. The anti-friction and anti-wear mechanisms were discussed and the lubricating effect of ZnAl{sub 2}O{sub 4} nanoparticles can be attributed to nano-bearings effect and tribo-sintering mechanism.« less

Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases.

PubMed

Smolensky, Michael H; Sackett-Lundeen, Linda L; Portaluppi, Francesco

2015-01-01

Routine exposure to artificial light at night (ALAN) in work, home, and community settings is linked with increased risk of breast and prostate cancer (BC, PC) in normally sighted women and men, the hypothesized biological rhythm mechanisms being frequent nocturnal melatonin synthesis suppression, circadian time structure (CTS) desynchronization, and sleep/wake cycle disruption with sleep deprivation. ALAN-induced perturbation of the CTS melatonin synchronizer signal is communicated maternally at the very onset of life and after birth via breast or artificial formula feedings. Nighttime use of personal computers, mobile phones, electronic tablets, televisions, and the like--now epidemic in adolescents and adults and highly prevalent in pre-school and school-aged children--is a new source of ALAN. However, ALAN exposure occurs concomitantly with almost complete absence of daytime sunlight, whose blue-violet (446-484 nm λ) spectrum synchronizes the CTS and whose UV-B (290-315 nm λ) spectrum stimulates vitamin D synthesis. Under natural conditions and clear skies, day/night and annual cycles of UV-B irradiation drive corresponding periodicities in vitamin D synthesis and numerous bioprocesses regulated by active metabolites augment and strengthen the biological time structure. Vitamin D insufficiency and deficiency are widespread in children and adults in developed and developing countries as a consequence of inadequate sunlight exposure. Past epidemiologic studies have focused either on exposure to too little daytime UV-B or too much ALAN, respectively, on vitamin D deficiency/insufficiency or melatonin suppression in relation to risk of cancer and other, e.g., psychiatric, hypertensive, cardiac, and vascular, so-called, diseases of civilization. The observed elevated incidence of medical conditions the two are alleged to influence through many complementary bioprocesses of cells, tissues, and organs led us to examine effects of the totality of the artificial light environment in which humans reside today. Never have chronobiologic or epidemiologic investigations comprehensively researched the potentially deleterious consequences of the combination of suppressed vitamin D plus melatonin synthesis due to life in today's man-made artificial light environment, which in our opinion is long overdue.

A simple, rapid, high-fidelity and cost-effective PCR-based two-step DNA synthesis method for long gene sequences.

PubMed

Xiong, Ai-Sheng; Yao, Quan-Hong; Peng, Ri-He; Li, Xian; Fan, Hui-Qin; Cheng, Zong-Ming; Li, Yi

2004-07-07

Chemical synthesis of DNA sequences provides a powerful tool for modifying genes and for studying gene function, structure and expression. Here, we report a simple, high-fidelity and cost-effective PCR-based two-step DNA synthesis (PTDS) method for synthesis of long segments of DNA. The method involves two steps. (i) Synthesis of individual fragments of the DNA of interest: ten to twelve 60mer oligonucleotides with 20 bp overlap are mixed and a PCR reaction is carried out with high-fidelity DNA polymerase Pfu to produce DNA fragments that are approximately 500 bp in length. (ii) Synthesis of the entire sequence of the DNA of interest: five to ten PCR products from the first step are combined and used as the template for a second PCR reaction using high-fidelity DNA polymerase pyrobest, with the two outermost oligonucleotides as primers. Compared with the previously published methods, the PTDS method is rapid (5-7 days) and suitable for synthesizing long segments of DNA (5-6 kb) with high G + C contents, repetitive sequences or complex secondary structures. Thus, the PTDS method provides an alternative tool for synthesizing and assembling long genes with complex structures. Using the newly developed PTDS method, we have successfully obtained several genes of interest with sizes ranging from 1.0 to 5.4 kb.

Sodium citrate (Na{sub 3}Cit)-assisted hydrothermal synthesis of uniform spindle-like SrMoO{sub 4}:Eu{sup 3+} phosphors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Xiaolei; Zhang, Yu; Li, Qiuyu

2014-11-15

Graphical abstract: A facile hydrothermal method for the synthesis of uniform spindle-like SrMoO{sub 4}:Eu{sup 3+} phosphors with the assistance of sodium citrate (Na{sub 3}Cit). - Highlights: • Well-crystallized spindle-like SrMoO{sub 4}:Eu{sup 3+} phosphors have been synthesized. • The influence of the reaction temperature and reaction time were clearly shown. • The dosage of Na{sub 3}Cit has a strong effect on the spindle-like SrMoO{sub 4}:Eu{sup 3+} phosphors. • The growth mechanism for the formation of final samples was proposed. - Abstract: Highly uniform spindle-like SrMoO{sub 4}:Eu{sup 3+} phosphors have been prepared by a facile hydrothermal method using sodium citrate (Na{sub 3}Cit)more » as the chelating reagent. X-ray powder diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectrum (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Fourier transform-infrared spectroscopy (FT-IR) and photoluminescence spectra (PL) were used to characterize the resulting samples. The dosage of sodium citrate, reaction temperature and reaction time play key roles in the formation of the final samples. The possible formation mechanism for SrMoO{sub 4}:Eu{sup 3+} phosphors has been proposed. Upon excitation by ultraviolet radiation, the as-synthesized SrMoO{sub 4}:Eu{sup 3+} phosphors show the characteristic {sup 5}D{sub 0}–{sup 7}F{sub J} (J = 1, 2, 3, 4) emission lines with red emission {sup 5}D{sub 0}–{sup 7}F{sub 2} (613 nm) as the most prominent group.« less

The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints

NASA Astrophysics Data System (ADS)

Newman, Andrew B.; Smith, Russell J.; Conroy, Charlie; Villaume, Alexa; van Dokkum, Pieter

2017-08-01

We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high-σ ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M */L using lensing and stellar dynamics. We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy & van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2-3σ tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08 M ⊙. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to <2σ. There is moderate evidence for a reduced number of low-mass stars in the SNELLS spectra, but no such evidence in a composite spectrum of matched-σ ETGs drawn from the SDSS. Such variation in the form of the IMF at low stellar masses (m ≲ 0.3 M ⊙), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M */L relative to the mean matched-σ ETG. We provide the spectra used in this study to facilitate future comparisons.

Synthesis, Characterization, and Fabrication of All Inorganic Quantum Dot LEDs

NASA Astrophysics Data System (ADS)

Salman, Haider Baqer

Quantum Dot LEDs with all inorganic materials are investigated in this thesis. The research was motivated by the potential disruptive technology of core shell quantum dots in lighting and display applications. These devices consisted of three main layers: hole transport layer (HTL), electron transport layer (ETL), and emissive layer where the emission of photons occurs. The latter part was formed of CdSe / ZnS core-shell quantum dots, which were synthesized following hot injection method. The ETL and the HTL were formed of zinc oxide nanocrystals and nickel oxide, respectively. Motivated by the low cost synthesis and deposition, NiO and ZnO were synthesized following sol-gel method and deposited using spin coating. The anode of the device was a commercial slide of indium tin oxide deposited on glass substrate while the cathode was a 100 nm aluminum layer that was deposited using an Auto 306T Edwards thermal evaporator. In this research, Raman spectroscopy, micro-photoluminescence spectroscopy, absorbance spectroscopy, X-ray diffraction (XRD) spectroscopy, and atomic force microscopy, were used to characterize the materials. Three sharp peaks were observed in the XRD measurements of the NiO thin film related to three planes and indicated a proper level of crystallinity. The AFM image of the same material indicated a roughness RMS value of 2 nm which was accepted for a device fabrication. The photoluminescence spectrum exhibited a peak at 515 nm for the quantum dots and a peak at 315 nm for the ZnO nanocrystals. The narrow shape of these spectra proved a limited amount of size variation. The transfer characteristics of the fabricated device indicated that the current density ramped up producing green light when the voltage was higher than 5 V to reach 160 mA cm -2 at 9 V.

IMPROVED CATALYSTS FOR HEAVY OIL UPGRADING BASED ON ZEOLITE Y NANOPARTICLES ENCAPSULATED IN STABLE NANOPOROUS HOST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Conrad Ingram; Mark Mitchell

2005-11-15

Composite materials of SBA-15/zeolite Y were synthesized from zeolite Y precursor and a synthesis mixture of mesoporous silicate SBA-15 via a hydrothermal process in the presence of a slightly acidic media of pH 4-6 with 2M H{sub 2}SO{sub 4}. The SBA-15/ZY composites showed Type IV adsorption isotherms, narrow BJH average pore size distribution of 4.9 nm, surface areas up to 800 m{sup 2}2/g and pore volumes 1.03 cm{sup 3}, all comparable to pure SBA-15 synthesized under similar conditions. Chemical analysis revealed Si/Al ratio down to 8.5 in the most aluminated sample, and {sup 27}AlSS MAS NMR confirmed aluminum was inmore » tetrahedral coordination. This method of introduction of Al in pure T{sub d} coordination is effective in comparison to other direct and post synthesis alumination methods. Bronsted acid sites were evident from a pyridinium peak at 1544 cm-1 in the FTIR spectrum after pyridine adsorption, and from NH{sub 3} -TPD experiments. SBA-15/ZY composites showed significant catalytic activities for the dealkylation of isopropylbenzene to benzene and propene, similar to those of commercial zeolite Y. It was observed that higher conversion for catalysts synthesized with high amount of ZY precursor mixture added to the SBA-15. Over all the composites has shown good catalytic activity. Further studies will be focused on gaining a better understand the nature of the precursor, and to characterize and to locate the acid sites in the composite material. The composite will also be evaluated for heavy oil conversion to naphtha and middle distillates.« less

The Initial Mass Function in the Nearest Strong Lenses from SNELLS: Assessing the Consistency of Lensing, Dynamical, and Spectroscopic Constraints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Newman, Andrew B.; Smith, Russell J.; Conroy, Charlie

2017-08-20

We present new observations of the three nearest early-type galaxy (ETG) strong lenses discovered in the SINFONI Nearby Elliptical Lens Locator Survey (SNELLS). Based on their lensing masses, these ETGs were inferred to have a stellar initial mass function (IMF) consistent with that of the Milky Way, not the bottom-heavy IMF that has been reported as typical for high- σ ETGs based on lensing, dynamical, and stellar population synthesis techniques. We use these unique systems to test the consistency of IMF estimates derived from different methods. We first estimate the stellar M {sub *}/ L using lensing and stellar dynamics.more » We then fit high-quality optical spectra of the lenses using an updated version of the stellar population synthesis models developed by Conroy and van Dokkum. When examined individually, we find good agreement among these methods for one galaxy. The other two galaxies show 2–3 σ tension with lensing estimates, depending on the dark matter contribution, when considering IMFs that extend to 0.08 M {sub ⊙}. Allowing a variable low-mass cutoff or a nonparametric form of the IMF reduces the tension among the IMF estimates to <2 σ . There is moderate evidence for a reduced number of low-mass stars in the SNELLS spectra, but no such evidence in a composite spectrum of matched- σ ETGs drawn from the SDSS. Such variation in the form of the IMF at low stellar masses ( m ≲ 0.3 M {sub ⊙}), if present, could reconcile lensing/dynamical and spectroscopic IMF estimates for the SNELLS lenses and account for their lighter M {sub *}/ L relative to the mean matched- σ ETG. We provide the spectra used in this study to facilitate future comparisons.« less

Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC).

PubMed

Niere, Farr; Namjoshi, Sanjeev; Song, Ehwang; Dilly, Geoffrey A; Schoenhard, Grant; Zemelman, Boris V; Mechref, Yehia; Raab-Graham, Kimberly F

2016-02-01

Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder-neurological disorders that exhibit elevated mTORC1 activity. Through a protein-protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and colocalizes with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Analysis of Proteins That Rapidly Change Upon Mechanistic/Mammalian Target of Rapamycin Complex 1 (mTORC1) Repression Identifies Parkinson Protein 7 (PARK7) as a Novel Protein Aberrantly Expressed in Tuberous Sclerosis Complex (TSC)*

PubMed Central

Niere, Farr; Namjoshi, Sanjeev; Song, Ehwang; Dilly, Geoffrey A.; Schoenhard, Grant; Zemelman, Boris V.; Mechref, Yehia; Raab-Graham, Kimberly F.

2016-01-01

Many biological processes involve the mechanistic/mammalian target of rapamycin complex 1 (mTORC1). Thus, the challenge of deciphering mTORC1-mediated functions during normal and pathological states in the central nervous system is challenging. Because mTORC1 is at the core of translation, we have investigated mTORC1 function in global and regional protein expression. Activation of mTORC1 has been generally regarded to promote translation. Few but recent works have shown that suppression of mTORC1 can also promote local protein synthesis. Moreover, excessive mTORC1 activation during diseased states represses basal and activity-induced protein synthesis. To determine the role of mTORC1 activation in protein expression, we have used an unbiased, large-scale proteomic approach. We provide evidence that a brief repression of mTORC1 activity in vivo by rapamycin has little effect globally, yet leads to a significant remodeling of synaptic proteins, in particular those proteins that reside in the postsynaptic density. We have also found that curtailing the activity of mTORC1 bidirectionally alters the expression of proteins associated with epilepsy, Alzheimer's disease, and autism spectrum disorder—neurological disorders that exhibit elevated mTORC1 activity. Through a protein–protein interaction network analysis, we have identified common proteins shared among these mTORC1-related diseases. One such protein is Parkinson protein 7, which has been implicated in Parkinson's disease, yet not associated with epilepsy, Alzheimers disease, or autism spectrum disorder. To verify our finding, we provide evidence that the protein expression of Parkinson protein 7, including new protein synthesis, is sensitive to mTORC1 inhibition. Using a mouse model of tuberous sclerosis complex, a disease that displays both epilepsy and autism spectrum disorder phenotypes and has overactive mTORC1 signaling, we show that Parkinson protein 7 protein is elevated in the dendrites and colocalizes with the postsynaptic marker postsynaptic density-95. Our work offers a comprehensive view of mTORC1 and its role in regulating regional protein expression in normal and diseased states. PMID:26419955

A Safer and Convenient Synthesis of Sulfathiazole for Undergraduate Organic and Medicinal Chemistry Classes

ERIC Educational Resources Information Center

Boyle, Jeff; Otty, Sandra; Sarojini, Vijayalekshmi

2012-01-01

A safer method for the synthesis of the sulfonamide drug sulfathiazole, for undergraduate classes, is described. This method improves upon procedures currently followed in several undergraduate teaching laboratories for the synthesis of sulfathiazole. Key features of this procedure include the total exclusion of pyridine, which has potential…

Spatial sound field synthesis and upmixing based on the equivalent source method.

PubMed

Bai, Mingsian R; Hsu, Hoshen; Wen, Jheng-Ciang

2014-01-01

Given scarce number of recorded signals, spatial sound field synthesis with an extended sweet spot is a challenging problem in acoustic array signal processing. To address the problem, a synthesis and upmixing approach inspired by the equivalent source method (ESM) is proposed. The synthesis procedure is based on the pressure signals recorded by a microphone array and requires no source model. The array geometry can also be arbitrary. Four upmixing strategies are adopted to enhance the resolution of the reproduced sound field when there are more channels of loudspeakers than the microphones. Multi-channel inverse filtering with regularization is exploited to deal with the ill-posedness in the reconstruction process. The distance between the microphone and loudspeaker arrays is optimized to achieve the best synthesis quality. To validate the proposed system, numerical simulations and subjective listening experiments are performed. The results demonstrated that all upmixing methods improved the quality of reproduced target sound field over the original reproduction. In particular, the underdetermined ESM interpolation method yielded the best spatial sound field synthesis in terms of the reproduction error, timbral quality, and spatial quality.

Shape and size engineered cellulosic nanomaterials as broad spectrum anti-microbial compounds.

PubMed

Sharma, Priyanka R; Kamble, Sunil; Sarkar, Dhiman; Anand, Amitesh; Varma, Anjani J

2016-06-01

Oxidized celluloses have been used for decades as antimicrobial wound gauzes and surgical cotton. We now report the successful synthesis of a next generation narrow size range (25-35nm) spherical shaped nanoparticles of 2,3,6-tricarboxycellulose based on cellulose I structural features, for applications as new antimicrobial materials. This study adds to our previous study of 6-carboxycellulose. A wide range of bacteria such as Escherichia coli, Staphloccocus aureus, Bacillus subtilis and Mycobacterium tuberculosis (non-pathogenic as well as pathogenic strains) were affected by these polymers in in vitro studies. Activity against Mycobacteria were noted at high concentrations (MIC99 values 250-1000μg/ml, as compared to anti-TB drug Isoniazid 0.3μg/ml). However, the broad spectrum activity of oxidized celluloses and their nanoparticles against a wide range of bacteria, including Mycobacteria, show that these materials are promising new biocompatible and biodegradable drug delivery vehicles wherein they can play the dual role of being a drug encapsulant as well as a broad spectrum anti-microbial and anti-TB drug. Copyright © 2016. Published by Elsevier B.V.

Prebiotic Polymer Synthesis and the Origin of Glycolytic Metabolism

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

1998-01-01

Our research resulted in several discoveries which contributed to understanding the origin and operation of life. (1) Most importantly, we discovered a new pathway of prebiotic amino acid synthesis in which formaldehyde and glycolaldehyde (formose reaction substrates) react with ammonia to give alanine and homoserine in the presence of thiol catalysts. The thiol-dependent synthesis of amino acids undoubtedly occurs via amino acid thioester intermediates capable of forming peptides. This 'one-pot' reaction system operates under mild aqueous conditions, and like modern amino acid biosynthesis, uses sugar intermediates which are converted to amino acids by energy-yielding redox disproportionation. Preliminary evidence suggests that this type of process can be "evolved" by a serial transfer methods that lead to enrichment of autocatalytic molecules. (2) We established that prebiotic peptide polymers can be made by condensation of amino acid thioesters (homocysteine thiolactone and S-(N-beta-orotidyl- diaminopropionic acid) ethanethiol), and that prebiotic polydisulfide polymers can be generated by oxidation of dithiols with iron(III) in minerals. (3) In our analysis of metabolism we discovered the primary energy source of biosynthesis -- chemical energy made available by the redox disproportionation of substrate carbon groups. We concluded that the energy and reactivity of sugars make them the optimal substrate for the origin and operation of terrestrial (or extraterrestrial) life. (4) Since it is likely that the use of optimal sugar substrates in biosynthesis sets the average oxidation number of functional biocarbon throughout the Universe near 0.0 (the reduction level of formaldehyde), we proposed that a line(s) in the microwave spectrum of formaldehyde could be rationally selected as a frequency for interstellar communication that symbolizes life. (5) Finally, in preparation for the analysis of Martian meteorite samples, we upgraded our HPLC system to one femtomole sensitivity, and developed a new electrophoretic method of sample preparation for HPLC analysis of the meteoritic amino acids. In a sample of the KT boundary layer from Sussex Wyoming, we found about 300 picomoles per gram of meteoritic alpha-aminoisobutyric acid per gram of KT layer.

Seaweeds: A resource for marine bionanotechnology.

PubMed

Vijayan, Sri Ramkumar; Santhiyagu, Prakash; Ramasamy, Ramasubburayan; Arivalagan, Pugazhendhi; Kumar, Gopalakrishnan; Ethiraj, Kannapiran; Ramaswamy, Babu Rajendran

2016-12-01

Marine bionanotechnology is one of the most promising areas of research in modern science and technology. Although there are multitude methods for the synthesis of nanoparticles (NPs), there is an increasing attention in developing high-yield, low-cost, non-toxic and eco-friendly procedures. The vital advantages of greener synthesis are cost-effective, reduced usage of toxic chemicals and abundant availability of resources. During the last ten years, there have been many biological entities used to elevate novel, greener and affordable methods for the metal NPs synthesis. Rate of synthesis and stability are higher for plant material mediated NPs. However, in comparison with terrestrial resources, marine resources have not been fully explored for synthesis of noble metal NPs. Our present review is designed to speculate the importance of usage of vast marine resources and its mediated NPs synthesis, in particular seaweed-mediated NPs synthesis to overcome the limitations involved in physical and chemical methods. Finally, recent advancements in greener synthesis of metal NPs, their size, distribution, morphology and applications such as antimicrobial, antifouling and anticancer potentials are briefly described along with portraying the prospective scope of research in this field without any negative impact on the environment. Copyright © 2016 Elsevier Inc. All rights reserved.

Calculation of power spectrums from digital time series with missing data points

NASA Technical Reports Server (NTRS)

Murray, C. W., Jr.

1980-01-01

Two algorithms are developed for calculating power spectrums from the autocorrelation function when there are missing data points in the time series. Both methods use an average sampling interval to compute lagged products. One method, the correlation function power spectrum, takes the discrete Fourier transform of the lagged products directly to obtain the spectrum, while the other, the modified Blackman-Tukey power spectrum, takes the Fourier transform of the mean lagged products. Both techniques require fewer calculations than other procedures since only 50% to 80% of the maximum lags need be calculated. The algorithms are compared with the Fourier transform power spectrum and two least squares procedures (all for an arbitrary data spacing). Examples are given showing recovery of frequency components from simulated periodic data where portions of the time series are missing and random noise has been added to both the time points and to values of the function. In addition the methods are compared using real data. All procedures performed equally well in detecting periodicities in the data.

Some New Methods of Music Synthesis.

DTIC Science & Technology

1980-08-01

AD-AO90 130 MASSACHUSETTS INST OF TECH CAMBRIDGE LAB FOR COMPUTE-ETC F/6 9/2 OME ME NW METHODS OF MUSIC SYNTHESIS. (U) AUG 80 W & PASEMAN...METHODS OF MUSIC SYNHEIS William Gerhard Paseman ~- August 1980 This research was supported by the Advanced Research Projects Agency of the Department of...black number) Artif icial Intelligence Msic Ccirposition Real Time Music Synthesis 20 ABSTRACT (Continue on reverse stde it necessary and identity by

Interface-Assisted Synthesis of 2D Materials: Trend and Challenges.

PubMed

Dong, Renhao; Zhang, Tao; Feng, Xinliang

2018-06-18

The discovery of graphene one decade ago has triggered enormous interest in developing two-dimensional materials (2DMs)-that is 2D allotropes of various elements or compounds (consisting of two or more covalently bonded elements) or molecular frameworks with periodic structures. At present, various synthesis strategies have been exploited to produce 2DMs, such as top-down exfoliation and bottom-up chemical vapor deposition and solution synthesis methods. In this review article, we will highlight the interfacial roles toward the controlled synthesis of inorganic and organic 2DMs with varied structural features. We will summarize the state-of-the-art progress on interfacial synthesis strategies and address their advancements in the structural, morphological, and crystalline control by the direction of the arrangement of the molecules or precursors at a confined 2D space. First, we will provide an overview of the interfaces and introduce their advantages and uniqueness for the synthesis of 2DMs, followed by a brief classification of inorganic and organic 2DMs achieved by interfacial synthesis. Next, the currently developed interfacial synthesis strategies combined with representative inorganic and organic 2DMs are summarized, including the description of method details, the corresponding structural features, and the insights into the advantages and limitations of the synthesis methods, along with some recommendable characterization methods for understanding the interfacial assembly of the precursors and crystal growth of 2DMs. After that, we will discuss several classes of emerging organic 2DMs with particular emphasis on the structural control by the interfacial synthesis strategies. Note that, inorganic 2DMs will not be categorized separately due to the fact that a number of review articles have covered the synthesis, structure, processing, and applications. Finally, the challenges and perspectives are provided regarding the future development of interface-assisted synthesis of 2DMs with diverse structural and functional control.

[New method of mixed gas infrared spectrum analysis based on SVM].

PubMed

Bai, Peng; Xie, Wen-Jun; Liu, Jun-Hua

2007-07-01

A new method of infrared spectrum analysis based on support vector machine (SVM) for mixture gas was proposed. The kernel function in SVM was used to map the seriously overlapping absorption spectrum into high-dimensional space, and after transformation, the high-dimensional data could be processed in the original space, so the regression calibration model was established, then the regression calibration model with was applied to analyze the concentration of component gas. Meanwhile it was proved that the regression calibration model with SVM also could be used for component recognition of mixture gas. The method was applied to the analysis of different data samples. Some factors such as scan interval, range of the wavelength, kernel function and penalty coefficient C that affect the model were discussed. Experimental results show that the component concentration maximal Mean AE is 0.132%, and the component recognition accuracy is higher than 94%. The problems of overlapping absorption spectrum, using the same method for qualitative and quantitative analysis, and limit number of training sample, were solved. The method could be used in other mixture gas infrared spectrum analyses, promising theoretic and application values.

Bark extract mediated green synthesis of silver nanoparticles: Evaluation of antimicrobial activity and antiproliferative response against osteosarcoma.

PubMed

Nayak, Debasis; Ashe, Sarbani; Rauta, Pradipta Ranjan; Kumari, Manisha; Nayak, Bismita

2016-01-01

In the current investigation we report the biosynthesis potentials of bark extracts of Ficus benghalensis and Azadirachta indica for production of silver nanoparticle without use of any external reducing or capping agent. The appearance of dark brown color indicated the complete nanoparticle synthesis which was further validated by absorbance peak by UV-vis spectroscopy. The morphology of the synthesized particles was characterized by Field emission- scanning electron microscopy (Fe-SEM) and atomic force microscopy (AFM). The X-ray diffraction (XRD) patterns clearly illustrated the crystalline phase of the synthesized nanoparticles. ATR-Fourier Transform Infrared (ATR-FTIR) spectroscopy was performed to identify the role of various functional groups in the nanoparticle synthesis. The synthesized nanoparticles showed promising antimicrobial activity against Gram negative (Escherichia coli, Pseudomonas aeruginosa and Vibrio cholerae) and Gram positive (Bacillus subtilis) bacteria. The synthesized nano Ag also showed antiproliferative activity against MG-63 osteosarcoma cell line in a dose dependent manner. Thus, these synthesized Ag nanoparticles can be used as a broad spectrum therapeutic agent against osteosarcoma and microorganisms. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and Characterization of C-Cinnamal Calix [4] Resorsinarena from Cinnamon Oil Waste West Sumatra

NASA Astrophysics Data System (ADS)

Etika, S. B.; Nasra, E.; Rilaztika, I.

2018-04-01

Synthesis and characterization of compound C-Cinnamal Calix [4] Resorsinarena (CCCR) of cinnamon oil waste have been done. This study was aimed to synthesis and characterize C-Cinnamal Calix [4] Resorsinarena from cinnamaldehyde violated cinnamon oil waste. C-Cinnamal Calix [4] Resorsinarena was synthesized by electrophilic substitution reaction of cinnamaldehyde isolated by the acid and resorcinol at 77oC temperature for 2 hour. The data analysis spectrum UV-VIS and FT-IR showed that the compound isolated cinnamaldehyde same as pure cinnamaldehyde compound. The characterization of C-Cinnamal Calix [4] Resorsinarena in the form of reddish-colored solids with melting point 3580C by using UV-VIS showed the presence of double bond, FT-IR showed the absorption at the wave number 3323,94 cm-1 indicating the ‑OH group, the wave number 1610,94 cm-1 showed the vibration C=C, the strong region absorption of 1500,86 cm-1 indicating the presence of an aromatic ring, the at 1442,88 cm-1 wave number indicating the presence of CH3.

Recent Approaches Toward Solid Phase Synthesis of β-Lactams

NASA Astrophysics Data System (ADS)

Mandal, Bablee; Ghosh, Pranab; Basu, Basudeb

Since the discovery of penicillin in 1929, β-lactam antibiotics have been recognized as potentially chemotherapeutic drugs of incomparable effectiveness, conjugating a broad spectrum of activity with very low toxicity. The primary motif azetidin-2-one ring (β-lactam) has been considered as specific pharmacophores and scaffolds. With the advent of combinatorial chemistry and automated parallel synthesis coupled with ample interests from the pharmaceutical industries, recent trends have been driven mostly by adopting solid phase techniques and polymer-supported synthesis of β-lactams. The present survey will present an overview of the developments on the polymer-supported and solid phase techniques for the preparation of β-lactam ring or β-lactam containing antibiotics published over the last decade. Both unsubstituted and substitutions with different functional groups at various positions of β-lactams have been synthesized using solid phase technology. However, Wang resin and application of Staudinger [2+2] cycloaddition reaction have remained hitherto the major choice. It may be expected that other solid phase approaches involving different resins would be developed in the coming years.

Base modifications affecting RNA polymerase and reverse transcriptase fidelity.

PubMed

Potapov, Vladimir; Fu, Xiaoqing; Dai, Nan; Corrêa, Ivan R; Tanner, Nathan A; Ong, Jennifer L

2018-06-20

Ribonucleic acid (RNA) is capable of hosting a variety of chemically diverse modifications, in both naturally-occurring post-transcriptional modifications and artificial chemical modifications used to expand the functionality of RNA. However, few studies have addressed how base modifications affect RNA polymerase and reverse transcriptase activity and fidelity. Here, we describe the fidelity of RNA synthesis and reverse transcription of modified ribonucleotides using an assay based on Pacific Biosciences Single Molecule Real-Time sequencing. Several modified bases, including methylated (m6A, m5C and m5U), hydroxymethylated (hm5U) and isomeric bases (pseudouridine), were examined. By comparing each modified base to the equivalent unmodified RNA base, we can determine how the modification affected cumulative RNA polymerase and reverse transcriptase fidelity. 5-hydroxymethyluridine and N6-methyladenosine both increased the combined error rate of T7 RNA polymerase and reverse transcriptases, while pseudouridine specifically increased the error rate of RNA synthesis by T7 RNA polymerase. In addition, we examined the frequency, mutational spectrum and sequence context of reverse transcription errors on DNA templates from an analysis of second strand DNA synthesis.

Psychosocial interventions for internalised stigma in people with a schizophrenia-spectrum diagnosis: A systematic narrative synthesis and meta-analysis.

PubMed

Wood, Lisa; Byrne, Rory; Varese, Filippo; Morrison, Anthony P

2016-10-01

It is acknowledged that people with a schizophrenia-spectrum diagnosis experience higher levels of stigma compared to any other mental health diagnosis. As a consequence, their experience of internalised stigma is likely to be the most detrimental and pervasive. Internalised stigma interventions have shown some benefits in those who experience serious mental illness including those with a schizophrenia-spectrum diagnosis. A systematic narrative review and meta-analysis were conducted examining the efficacy of internalised stigma interventions for people with a schizophrenia-spectrum diagnosis. Randomised Controlled Trials, controlled trials, and cohort studies were included and assessed against quality criteria. The search identified 12 studies; 7 randomised controlled trials, 3 cohort studies and 2 controlled trials. A variety of psychosocial interventions were utilised with the majority employing Cognitive Behaviour Therapy (CBT), psychoeducation and social skills training. The core outcomes used to examine the efficacy of the intervention were internalised stigma, self-esteem, empowerment, and functioning. The meta-analysis revealed an improvement in internalised stigma favouring the internalised stigma intervention but was not significant (5 RCTs, n=200). Self-efficacy and insight were significantly improved favouring the internalised stigma intervention. Internalised stigma interventions show promise in those with schizophrenia-spectrum diagnoses. Existing interventions have demonstrated small effects and employed small samples. Large scale RCTs are required to further develop the evidence base of more targeted interventions. Copyright © 2016 Elsevier B.V. All rights reserved.

Plasma-assisted synthesis of MoS2

NASA Astrophysics Data System (ADS)

Campbell, Philip M.; Perini, Christopher J.; Chiu, Johannes; Gupta, Atul; Ray, Hunter S.; Chen, Hang; Wenzel, Kevin; Snyder, Eric; Wagner, Brent K.; Ready, Jud; Vogel, Eric M.

2018-03-01

There has been significant interest in transition metal dichalcogenides (TMDs), including MoS2, in recent years due to their potential application in novel electronic and optical devices. While synthesis methods have been developed for large-area films of MoS2, many of these techniques require synthesis temperatures of 800 °C or higher. As a result of the thermal budget, direct synthesis requiring high temperatures is incompatible with many integrated circuit processes as well as flexible substrates. This work explores several methods of plasma-assisted synthesis of MoS2 as a way to lower the synthesis temperature. The first approach used is conversion of a naturally oxidized molybdenum thin film to MoS2 using H2S plasma. Conversion is demonstrated at temperatures as low as 400 °C, and the conversion is enabled by hydrogen radicals which reduce the oxidized molybdenum films. The second method is a vapor phase reaction incorporating thermally evaporated MoO3 exposed to a direct H2S plasma, similar to chemical vapor deposition (CVD) synthesis of MoS2. Synthesis at 400 °C results in formation of super-stoichiometric MoS2 in a beam-interrupted growth process. A final growth method relies on a cyclical process in which a small amount of Mo is sputtered onto the substrate and is subsequently sulfurized in a H2S plasma. Similar results could be realized using an atomic layer deposition (ALD) process to deposit the Mo film. Compared to high temperature synthesis methods, the lower temperature samples are lower quality, potentially due to poor crystallinity or higher defect density in the films. Temperature-dependent conductivity measurements are consistent with hopping conduction in the plasma-assisted synthetic MoS2, suggesting a high degree of disorder in the low-temperature films. Optimization of the plasma-assisted synthesis process for slower growth rate and better stoichiometry is expected to lead to high quality films at low growth temperature.

Measurement of electron density using reactance cutoff probe

DOE Office of Scientific and Technical Information (OSTI.GOV)

You, K. H.; Seo, B. H.; Kim, J. H.

2016-05-15

This paper proposes a new measurement method of electron density using the reactance spectrum of the plasma in the cutoff probe system instead of the transmission spectrum. The highly accurate reactance spectrum of the plasma-cutoff probe system, as expected from previous circuit simulations [Kim et al., Appl. Phys. Lett. 99, 131502 (2011)], was measured using the full two-port error correction and automatic port extension methods of the network analyzer. The electron density can be obtained from the analysis of the measured reactance spectrum, based on circuit modeling. According to the circuit simulation results, the reactance cutoff probe can measure themore » electron density more precisely than the previous cutoff probe at low densities or at higher pressure. The obtained results for the electron density are presented and discussed for a wide range of experimental conditions, and this method is compared with previous methods (a cutoff probe using the transmission spectrum and a single Langmuir probe).« less

School Restructuring Options/Alternatives: Synthesis on Attitudes Expressed by Participants of the Montana Rural Education Conference (16th, Dillon, Montana, June 22-24, 1994). Follow-up Report to the Montana Rural Education Center.

ERIC Educational Resources Information Center

Ley, Joyce

This report synthesizes the experience-based ideas that emerged from small group interaction at the 16th annual Montana Rural Education Conference, which focused on the pros and cons of school district consolidation. Conferees first heard from panelists and speakers expressing a spectrum of positive and negative positions on the consolidation…

Classics in Chemical Neuroscience: Diazepam (Valium)

PubMed Central

2014-01-01

Diazepam (Valium) is among the most successful drugs from the onset of the psychopharmacological revolution that began during the 1950s. Efficacious in treating a wide-spectrum of CNS disorders, including anxiety and epilepsy, it set the standard for pharmacotherapy in terms of potency, onset of action, and safety. In this Review, the legacy of diazepam to chemical neuroscience will be considered along with its synthesis, pharmacology, drug metabolism, adverse events and dependence, clinical use, and regulatory issues. PMID:24552479

Synaptic synthesis, dephosphorylation, and degradation: a novel paradigm for an activity-dependent neuronal control of CDKL5.

PubMed

La Montanara, Paolo; Rusconi, Laura; Locarno, Albina; Forti, Lia; Barbiero, Isabella; Tramarin, Marco; Chandola, Chetan; Kilstrup-Nielsen, Charlotte; Landsberger, Nicoletta

2015-02-13

Mutations in the X-linked CDKL5 (cyclin-dependent kinase-like 5) gene have been associated with several forms of neurodevelopmental disorders, including atypical Rett syndrome, autism spectrum disorders, and early infantile epileptic encephalopathy. Accordingly, loss of CDKL5 in mice results in autistic-like features and impaired neuronal communication. Although the biological functions of CDKL5 remain largely unknown, recent pieces of evidence suggest that CDKL5 is involved in neuronal plasticity. Herein, we show that, at all stages of development, neuronal depolarization induces a rapid increase in CDKL5 levels, mostly mediated by extrasomatic synthesis. In young neurons, this induction is prolonged, whereas in more mature neurons, NMDA receptor stimulation induces a protein phosphatase 1-dependent dephosphorylation of CDKL5 that is mandatory for its proteasome-dependent degradation. As a corollary, neuronal activity leads to a prolonged induction of CDKL5 levels in immature neurons but to a short lasting increase of the kinase in mature neurons. Recent results demonstrate that many genes associated with autism spectrum disorders are crucial components of the activity-dependent signaling networks regulating the composition, shape, and strength of the synapse. Thus, we speculate that CDKL5 deficiency disrupts activity-dependent signaling and the consequent synapse development, maturation, and refinement. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Synthesis and characterization of Sn/zeolite and catalytic activity test in the esterification reaction of sludge oil

NASA Astrophysics Data System (ADS)

Alimuddin, Andi Hairil; Usman, Thamrin; Wahyuni, Nelly; Rudiyansyah, Prawatya, Yopa Eka; Astar, Ismail; Yustira, Yudi

2017-03-01

Synthesis of Sn-Zeolite has been made to use for esterification reaction of free fatty acids in sludge oil. Catalyst characterization was accomplished using X-Ray Diffraction (XRD), X-Ray Flourecence (XRF), and Fourier Transform Infra Red (FTIR). Catalyst Sn/zeolite was synthesized by impregnated Sn of SnCl2 into the zeolite. The amount of Sn impregnated base on the value of cation exchange capacity (CEC) of zeolites. Esterification reaction of fatty acids from sludge oil using Sn/Zeolite catalyst was did by variated the reaction time. XRD analysis results showed that the catalyst Sn/zeolite was dominated by modernit and quartz. XRF analysis results was increasing amount of Sn metal and the Si/Al ratio on Sn/zeolite catalyst along with addition of Sn metal. FTIR analysis results showed that the catalyst synthesized had Bronsted acid side (the spectrum 1639.4; 1656.7; 1654.8 cm-1) and the Lewis acid (spectrum 1400.2 and 1402.2 cm-1). The results showed that the optimum conditions of esterification reaction in 4 hours reaction time, 5% concentration of the catalyst, and molar ratio was about 1:10 with a conversion percentage of products reached 96.00%, which can be achieved with a ratio was about 4:1 between Sn and zeolite on Sn/zeolite catalyst.

Abnormal melatonin synthesis in autism spectrum disorders.

PubMed

Melke, J; Goubran Botros, H; Chaste, P; Betancur, C; Nygren, G; Anckarsäter, H; Rastam, M; Ståhlberg, O; Gillberg, I C; Delorme, R; Chabane, N; Mouren-Simeoni, M-C; Fauchereau, F; Durand, C M; Chevalier, F; Drouot, X; Collet, C; Launay, J-M; Leboyer, M; Gillberg, C; Bourgeron, T

2008-01-01

Melatonin is produced in the dark by the pineal gland and is a key regulator of circadian and seasonal rhythms. A low melatonin level has been reported in individuals with autism spectrum disorders (ASD), but the underlying cause of this deficit was unknown. The ASMT gene, encoding the last enzyme of melatonin synthesis, is located on the pseudo-autosomal region 1 of the sex chromosomes, deleted in several individuals with ASD. In this study, we sequenced all ASMT exons and promoters in individuals with ASD (n=250) and compared the allelic frequencies with controls (n=255). Non-conservative variations of ASMT were identified, including a splicing mutation present in two families with ASD, but not in controls. Two polymorphisms located in the promoter (rs4446909 and rs5989681) were more frequent in ASD compared to controls (P=0.0006) and were associated with a dramatic decrease in ASMT transcripts in blood cell lines (P=2 x 10(-10)). Biochemical analyses performed on blood platelets and/or cultured cells revealed a highly significant decrease in ASMT activity (P=2 x 10(-12)) and melatonin level (P=3 x 10(-11)) in individuals with ASD. These results indicate that a low melatonin level, caused by a primary deficit in ASMT activity, is a risk factor for ASD. They also support ASMT as a susceptibility gene for ASD and highlight the crucial role of melatonin in human cognition and behavior.

Heritability of the melatonin synthesis variability in autism spectrum disorders.

PubMed

Benabou, Marion; Rolland, Thomas; Leblond, Claire S; Millot, Gaël A; Huguet, Guillaume; Delorme, Richard; Leboyer, Marion; Pagan, Cécile; Callebert, Jacques; Maronde, Erik; Bourgeron, Thomas

2017-12-18

Autism Spectrum Disorders (ASD) are heterogeneous neurodevelopmental disorders with a complex genetic architecture. They are characterized by impaired social communication, stereotyped behaviors and restricted interests and are frequently associated with comorbidities such as intellectual disability, epilepsy and severe sleep disorders. Hyperserotonemia and low melatonin levels are among the most replicated endophenotypes reported in ASD, but their genetic causes remain largely unknown. Based on the biochemical profile of 717 individuals including 213 children with ASD, 128 unaffected siblings and 376 parents and other relatives, we estimated the heritability of whole-blood serotonin, platelet N-acetylserotonin (NAS) and plasma melatonin levels, as well as the two enzymes arylalkylamine N-acetyltransferase (AANAT) and acetylserotonin O-methyltransferase (ASMT) activities measured in platelets. Overall, heritability was higher for NAS (0.72 ± 0.091) and ASMT (0.59 ± 0.097) compared with serotonin (0.31 ± 0.078), AANAT (0.34 ± 0.077) and melatonin (0.22 ± 0.071). Bivariate analyses showed high phenotypic and genetic correlations between traits of the second step of the metabolic pathway (NAS, ASMT and melatonin) indicating the contribution of shared genetic factors. A better knowledge of the heritability of the melatonin synthesis variability constitutes an important step to identify the factors that perturb this pathway in individuals with ASD.

[Study on rapid determination and analysis of rocket kerosene by near infrared spectrum and chemometrics].

PubMed

Xia, Ben-Li; Cong, Ji-Xin; Li, Xia; Wang, Xuan-Jun

2011-06-01

The rocket kerosene quality properties such as density, distillation range, viscosity and iodine value were successfully measured based on their near-infrared spectrum (NIRS) and chemometrics. In the present paper, more than 70 rocket kerosene samples were determined by near infrared spectrum, the models were built using the partial least squares method within the appropriate wavelength range. The correlation coefficients (R2) of every rocket kerosene's quality properties ranged from 0.862 to 0.999. Ten unknown samples were determined with the model, and the result showed that the prediction accuracy of near infrared spectrum method accords with standard analysis requirements. The new method is well suitable for replacing the traditional standard method to rapidly determine the properties of the rocket kerosene.

Enantioselective Synthesis of SNAP-7941

PubMed Central

Goss, Jennifer M.; Schaus, Scott E.

2009-01-01

An enantioselective synthesis of SNAP-7941, a potent melanin concentrating hormone receptor antagonist, was achieved using two organocatalytic methods. The first method utilized to synthesize the enantioenriched dihydropyrimidone core was the Cinchona alkaloid-catalyzed Mannich reaction of β-keto esters to acyl imines and the second was chiral phosphoric acid-catalyzed Biginelli reaction. Completion of the synthesis was accomplished via selective urea formation at the N3 position of the dihydropyrimidone with the 3-(4-phenylpiperidin-1-yl)propyl amine side chain fragment. The synthesis of SNAP-7921 highlights the utility of asymmetric organocatalytic methods in the construction of an important class of chiral heterocycles. PMID:18767801

Highly efficient water-mediated approach to access benzazoles: metal catalyst and base-free synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles.

PubMed

Bala, Manju; Verma, Praveen Kumar; Sharma, Deepika; Kumar, Neeraj; Singh, Bikram

2015-05-01

An efficient water-catalyzed method has been developed for the synthesis of 2-substituted benzimidazoles, benzoxazoles, and benzothiazoles in one step. The present method excludes the usage of toxic metal catalysts and bases to produce benzazoles in good to excellent yields. An efficient and versatile water-mediated method has been established for the synthesis of various 2-arylbenzazoles. The present protocol excludes the usage of any catalyst and additive provided excellent selectivities and yields with high functional group tolerance for the synthesis of 2-arylated benzimidazoles, benzoxazoles, and benzothiazoles. Benzazolones were also synthesized using similar reaction protocol.

Reduced graphene oxide and Ag wrapped TiO{sub 2} photocatalyst for enhanced visible light photocatalysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leong, Kah Hon; Sim, Lan Ching; Jang, Min

2015-10-01

A well-organised reduced graphene oxide (RGO) and silver (Ag) wrapped TiO{sub 2} nano-hybrid was successfully achieved through a facile and easy route. The inherent characteristics of the synthesized RGO-Ag/TiO{sub 2} were revealed through crystalline phase, morphology, chemical composition, Raman scattering, UV-visible absorption, and photoluminescence analyses. The adopted synthesis route significantly controlled the uniform formation of silver nanoparticles and contributed for the absorption of light in the visible spectrum through localized surface plasmon resonance effects. The wrapped RGO nanosheets triggered the electron mobility and promoted visible light shift towards red spectrum. The accomplishment of synergised effect of RGO and Ag wellmore » degraded Bisphenol A under visible light irradiation with a removal efficiency of 61.9%.« less

Basic Modeling of the Solar Atmosphere and Spectrum

NASA Technical Reports Server (NTRS)

Avrett, Eugene H.; Wagner, William J. (Technical Monitor)

2000-01-01

During the last three years we have continued the development of extensive computer programs for constructing realistic models of the solar atmosphere and for calculating detailed spectra to use in the interpretation of solar observations. This research involves two major interrelated efforts: work by Avrett and Loeser on the Pandora computer program for optically thick non-LTE modeling of the solar atmosphere including a wide range of physical processes, and work by Kurucz on the detailed high-resolution synthesis of the solar spectrum using data for over 58 million atomic and molecular lines. Our objective is to construct atmospheric models from which the calculated spectra agree as well as possible with high-and low-resolution observations over a wide wavelength range. Such modeling leads to an improved understanding of the physical processes responsible for the structure and behavior of the atmosphere.

Synthesis and characterization β-ketoamine ligands

NASA Astrophysics Data System (ADS)

Zaid, Nurzati Amani Mohamed; Hassan, Nur Hasyareeda; Karim, Nurul Huda Abd

2018-04-01

β-ketoamine ligands are important members of heterodonor ligand because of their ease of preparation and modification of both steric and/or electronic effects. Complexes with β-ketoamine has received much less attention and there has been no study about this complex with β-ketoamine in ionic liquid reported. Two type of β-ketoamine ligands which are 4-amino-3-pentene-2-onato (A) and 3-amino-2-butenoic acid methyl ester (B) have been synthesized in this work. The resulting compound formed was characterized using standard spectroscopic and structural techniques which includes 1H and 13C, NMR spectroscopy and FTIR spectroscopy. The 1H and 13C NMR spectrum displayed all the expected signals with correct integration and multiplicity. And it is proved that there are some differences between two ligands as observed in NMR and FTIR spectrum.

Inference of relativistic electron spectra from measurements of inverse Compton radiation

NASA Astrophysics Data System (ADS)

Craig, I. J. D.; Brown, J. C.

1980-07-01

The inference of relativistic electron spectra from spectral measurement of inverse Compton radiation is discussed for the case where the background photon spectrum is a Planck function. The problem is formulated in terms of an integral transform that relates the measured spectrum to the unknown electron distribution. A general inversion formula is used to provide a quantitative assessment of the information content of the spectral data. It is shown that the observations must generally be augmented by additional information if anything other than a rudimentary two or three parameter model of the source function is to be derived. It is also pointed out that since a similar equation governs the continuum spectra emitted by a distribution of black-body radiators, the analysis is relevant to the problem of stellar population synthesis from galactic spectra.

Potent and broad-spectrum antibacterial activity of indole-based bisamidine antibiotics: synthesis and SAR of novel analogs of MBX 1066 and MBX 1090

PubMed Central

Williams, John D.; Nguyen, Son T.; Gu, Shen; Ding, Xiaoyuan; Butler, Michelle M.; Tashjian, Tommy F.; Opperman, Timothy J.; Panchal, Rekha G.; Bavari, Sina; Peet, Norton P.; Moir, Donald T.; Bowlin, Terry L.

2013-01-01

The prevalence of drug-resistant bacteria in the clinic has propelled a concerted effort to find new classes of antibiotics that will circumvent current modes of resistance. We have previously described a set of bisamidine antibiotics that contains a core composed of two indoles and a central linker. The first compounds of the series, MBX 1066 and MBX 1090, have potent antibacterial properties against a wide range of Gram-positive and Gram-negative bacteria. We have conducted a systematic exploration of the amidine functionalities, the central linker, and substituents at the indole 3-position to determine the factors involved in potent antibacterial activity. Some of the newly synthesized compounds have even more potent and broad-spectrum activity than MBX 1066 and MBX 1090. PMID:24239389

Synthesis of Ag-Cu-Pd alloy thin films by DC-magnetron sputtering: Case study on microstructures and optical properties

NASA Astrophysics Data System (ADS)

Rezaee, Sahar; Ghobadi, Nader

2018-06-01

The present study aims to investigate optical properties of Ag-Cu-Pd alloy thin films synthesized by DC-magnetron sputtering method. The thin films are deposited on the glass and silicon substrates using Argon gas and Ag-Cu-Pd target. XRD analysis confirms the successful growth of Ag, Cu, and Pd NPs with FCC crystalline structure. Moreover, UV-visible absorption spectroscopy is applied to determine optical properties of the prepared samples which are affected by changes in surface morphology. The existence of single surface plasmon resonance (SPR) peak near 350 nm proves the formation of silver nanoparticles with a slight red shift through increasing deposition time. Ineffective thickness method (ITM) and Derivation of ineffective thickness method (DITM) are applied to extract optical band gap and transition type via absorption spectrum. SEM and AFM analyses show the distribution of near-spherical nanoparticles covering the surface of thin films. Furthermore, thickness variation affects the grain size. In addition, TEM image reveals the uniform size distribution of nanoparticles with an average particle size of about 15 nm. The findings show that increasing grain size and crystallite order along with the decrease of structural defect and disorders decrease optical band gap from 3.86 eV to 2.58 eV.

Measuring the activity of a {sup 51}Cr neutrino source based on the gamma-radiation spectrum

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gorbachev, V. V., E-mail: vvgor-gfb1@mail.ru; Gavrin, V. N.; Ibragimova, T. V.

A technique for the measurement of activities of intense β sources by measuring the continuous gamma-radiation (internal bremsstrahlung) spectra is developed. A method for reconstructing the spectrum recorded by a germanium semiconductor detector is described. A method for the absolute measurement of the internal bremsstrahlung spectrum of {sup 51}Cr is presented.

Recent Advances in the Synthesis and Stabilization of Nickel and Nickel Oxide Nanoparticles: A Green Adeptness

PubMed Central

Rani, Aneela

2016-01-01

Green protocols for the synthesis of nanoparticles have been attracting a lot of attention because they are eco-friendly, rapid, and cost-effective. Nickel and nickel oxide nanoparticles have been synthesized by green routes and characterized for impact of green chemistry on the properties and biological effects of nanoparticles in the last five years. Green synthesis, properties, and applications of nickel and nickel oxide nanoparticles have been reported in the literature. This review summarizes the synthesis of nickel and nickel oxide nanoparticles using different biological systems. This review also provides comparative overview of influence of chemical synthesis and green synthesis on structural properties of nickel and nickel oxide nanoparticles and their biological behavior. It concludes that green methods for synthesis of nickel and nickel oxide nanoparticles are better than chemical synthetic methods. PMID:27413375

[A method for the analysis of overlapped peaks in the high performance liquid chromatogram based on spectrum analysis].

PubMed

Liu, Bao; Fan, Xiaoming; Huo, Shengnan; Zhou, Lili; Wang, Jun; Zhang, Hui; Hu, Mei; Zhu, Jianhua

2011-12-01

A method was established to analyse the overlapped chromatographic peaks based on the chromatographic-spectra data detected by the diode-array ultraviolet detector. In the method, the three-dimensional data were de-noised and normalized firstly; secondly the differences and clustering analysis of the spectra at different time points were calculated; then the purity of the whole chromatographic peak were analysed and the region were sought out in which the spectra of different time points were stable. The feature spectra were extracted from the spectrum-stable region as the basic foundation. The nonnegative least-square method was chosen to separate the overlapped peaks and get the flow curve which was based on the feature spectrum. The three-dimensional divided chromatographic-spectrum peak could be gained by the matrix operations of the feature spectra with the flow curve. The results displayed that this method could separate the overlapped peaks.

Ultrafast, 2 min synthesis of monolayer-protected gold nanoclusters (d < 2 nm)

NASA Astrophysics Data System (ADS)

Martin, Matthew N.; Li, Dawei; Dass, Amala; Eah, Sang-Kee

2012-06-01

An ultrafast synthesis method is presented for hexanethiolate-coated gold nanoclusters (d < 2 nm, <250 atoms per nanocluster), which takes only 2 min and can be easily reproduced. With two immiscible solvents, gold nanoclusters are separated from the reaction byproducts fast and easily without any need for post-synthesis cleaning.An ultrafast synthesis method is presented for hexanethiolate-coated gold nanoclusters (d < 2 nm, <250 atoms per nanocluster), which takes only 2 min and can be easily reproduced. With two immiscible solvents, gold nanoclusters are separated from the reaction byproducts fast and easily without any need for post-synthesis cleaning. Electronic supplementary information (ESI) available: Experimental details of gold nanocluster synthesis and mass-spectrometry. See DOI: 10.1039/c2nr30890h

One-pot synthesis and antiproliferative activity of novel double-modified derivatives of the polyether ionophore monensin A.

PubMed

Klejborowska, Greta; Maj, Ewa; Wietrzyk, Joanna; Stefańska, Joanna; Huczyński, Adam

2018-05-02

Monensin A (MON) is a polyether ionophore antibiotic, which shows a wide spectrum of biological activity. New MON derivatives such as double-modified ester-carbonates and double-modified amide-carbonates were obtained by a new and efficient one-pot synthesis with triphosgene as the activating reagent and the respective alcohol or amine. All new derivatives were tested for their antiproliferative activity against two drug-sensitive (MES-SA, LoVo) and two drug-resistant (MES-SA/DX5, LoVo/DX) cancer cell lines, and were also studied for their antimicrobial activity against different Staphylococcus aureus and Staphylococcus epidermidis bacterial strains. For the first time, the activity of MON and its derivatives against MES-SA and MES-SA/DX5 were evaluated. © 2018 John Wiley & Sons A/S.

[Tetracyclines, sulfonamides and metronidazole].

PubMed

Pérez-Trallero, Emilio; Iglesias, Luis

2003-11-01

Tetracyclines form a group of natural and semisynthetic products that acts inhibiting the bacterial protein synthesis. They are bacteriostatic agents, exhibiting activity against a wide range of organisms, but they are at the present of limited use because of their acquired resistance. Doxycycline is currently the most frequently used tetracycline in human medicine and it is included in the List of Essential Medicines of the World Health Organization. Sulfonamides are synthetic, broad-spectrum bacteriostatic antibiotics. They were the first effective systemic antimicrobial agents. Their mode of action is based on the inhibition of DNA synthesis. Due to their toxicity and high adquired resistance their use is currently very low. Metronidazole is the main compound of 5-nitroimidazole family. It is a very active bactericidal antibiotic against anaerobic and some microaerophilic bacteria and it is still very useful in the treatment of bacterian and parasitic infections.

Fluid synthesis and structure of a new polymorphic modification of boron nitride

NASA Astrophysics Data System (ADS)

Pokropivny, V. V.; Smolyar, A. S.; Ovsiannikova, L. I.; Pokropivny, A. V.; Kuts, V. A.; Lyashenko, V. I.; Nesterenko, Yu. V.

2013-04-01

A new previously unknown phase of boron nitride with a hardness of 0.41-0.63 GPa has been pre-pared by the supercritical fluid synthesis. The presence of a new phase is confirmed by the X-ray spectra and IR absorption spectra, where new reflections and bands are distinguished. The fundamental reflection of the X-ray diffraction pattern is d = 0.286-0.291 nm, and the characteristic band in the infrared absorption spectrum is observed at 704 cm-1. The X-ray diffraction pattern and the experimental and theoretical infrared absorption spectra show that a new synthesized boron nitride phase can be a cluster crystal (space group 211) with a simple cubic lattice. Cage clusters of a fullerene-like morphology B24N24 with point symmetry O are arranged in lattice sites.

The Closure of the Cycle: Enzymatic Synthesis and Functionalization of Bio-Based Polyesters.

PubMed

Pellis, Alessandro; Herrero Acero, Enrique; Ferrario, Valerio; Ribitsch, Doris; Guebitz, Georg M; Gardossi, Lucia

2016-04-01

The polymer industry is under pressure to mitigate the environmental cost of petrol-based plastics. Biotechnologies contribute to the gradual replacement of petrol-based chemistry and the development of new renewable products, leading to the closure of carbon circle. An array of bio-based building blocks is already available on an industrial scale and is boosting the development of new generations of sustainable and functionally competitive polymers, such as polylactic acid (PLA). Biocatalysts add higher value to bio-based polymers by catalyzing not only their selective modification, but also their synthesis under mild and controlled conditions. The ultimate aim is the introduction of chemical functionalities on the surface of the polymer while retaining its bulk properties, thus enlarging the spectrum of advanced applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Green synthesis of graphene and its cytotoxic effects in human breast cancer cells

PubMed Central

Gurunathan, Sangiliyandi; Han, Jae Woong; Eppakayala, Vasuki; Kim, Jin-Hoi

2013-01-01

Background: This paper describes an environmentally friendly (“green”) approach for the synthesis of soluble graphene using Bacillus marisflavi biomass as a reducing and stabilizing agent under mild conditions in aqueous solution. In addition, the study reported here investigated the cytotoxicity effects of graphene oxide (GO) and bacterially reduced graphene oxide (B-rGO) on the inhibition of cell viability, reactive oxygen species (ROS) generation, and membrane integrity in human breast cancer cells. Methods: The reduction of GO was characterized by ultraviolet–visible spectroscopy. Size distribution was analyzed by dynamic light scattering. Further, X-ray diffraction and high-resolution scanning electron microscopy were used to investigate the crystallinity of graphene and the morphologies of prepared graphene, respectively. The formation of defects further supports the bio-functionalization of graphene, as indicated in the Raman spectrum of B-rGO. Surface morphology and the thickness of the GO and B-rGO were analyzed using atomic force microscopy, while the biocompatibility of GO and B-rGO were investigated using WST-8 assays on MCF-7 cells. Finally, cellular toxicity was evaluated by ROS generation and membrane integrity assays. Results: In this study, we demonstrated an environmentally friendly, cost-effective, and simple method for the preparation of water-soluble graphene using bacterial biomass. This reduction method avoids the use of toxic reagents such as hydrazine and hydrazine hydrate. The synthesized soluble graphene was confirmed using various analytical techniques. Our results suggest that both GO and B-rGO exhibit toxicity to MCF-7 cells in a dose-dependent manner, with a dose > 60 μg/mL exhibiting obvious cytotoxicity effects, such as decreasing cell viability, increasing ROS generation, and releasing of lactate dehydrogenase. Conclusion: We developed a green and a simple approach to produce graphene using bacterial biomass as a reducing and stabilizing agent. The proposed approach confers B-rGO with great potential for various biological and biomedical applications. PMID:23687445

Neurite outgrowth stimulatory effects of myco synthesized AuNPs from Hericium erinaceus (Bull.: Fr.) Pers. on pheochromocytoma (PC-12) cells

PubMed Central

Raman, Jegadeesh; Lakshmanan, Hariprasath; John, Priscilla A; Zhijian, Chan; Periasamy, Vengadesh; David, Pamela; Naidu, Murali; Sabaratnam, Vikineswary

2015-01-01

Background Hericium erinaceus has been reported to have a wide range of medicinal properties such as stimulation of neurite outgrowth, promotion of functional recovery of axonotmetic peroneal nerve injury, antioxidant, antihypertensive, and antidiabetic properties. In recent years, the green synthesis of gold nanoparticles (AuNPs) has attracted intense interest due to the potential use in biomedical applications. The aim of this study was to investigate the effects of AuNPs from aqueous extract of H. erinaceus on neurite outgrowth of rat pheochromocytoma (PC-12) cells. Methods The formation of AuNPs was characterized by UV–visible spectrum, energy dispersive X-ray (EDX), field-emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), particle size distribution, and Fourier transform-infrared spectroscopy (FTIR). Furthermore, the neurite extension study of synthesized AuNPs was evaluated by in vitro assay. Results The AuNPs exhibited maximum absorbance between 510 and 600 nm in UV–visible spectrum. FESEM and TEM images showed the existence of nanoparticles with sizes of 20–40 nm. FTIR measurements were carried out to identify the possible biomolecules responsible for capping and efficient stabilization of the nanoparticles. The purity and the crystalline properties were confirmed by EDX diffraction analysis, which showed strong signals with energy peaks in the range of 2–2.4 keV, indicating the existence of gold atoms. The synthesized AuNPs showed significant neurite extension on PC-12 cells. Nerve growth factor 50 ng/mL was used as a positive control. Treatment with different concentrations (nanograms) of AuNPs resulted in neuronal differentiation and neuronal elongation. AuNPs induced maximum neurite outgrowth of 13% at 600 ng/mL concentration. Conclusion In this study, the AuNPs synthesis was achieved by a simple, low-cost, and rapid bioreduction approach. AuNPs were shown to have potential neuronal differentiation and stimulated neurite outgrowth. The water-soluble bioconstituents could be responsible for the neuroactivity. This is the first report for the biosynthesis of AuNPs using the hot aqueous extract of H. erinaceus. PMID:26425086

Methods for the thematic synthesis of qualitative research in systematic reviews

PubMed Central

Thomas, James; Harden, Angela

2008-01-01

Background There is a growing recognition of the value of synthesising qualitative research in the evidence base in order to facilitate effective and appropriate health care. In response to this, methods for undertaking these syntheses are currently being developed. Thematic analysis is a method that is often used to analyse data in primary qualitative research. This paper reports on the use of this type of analysis in systematic reviews to bring together and integrate the findings of multiple qualitative studies. Methods We describe thematic synthesis, outline several steps for its conduct and illustrate the process and outcome of this approach using a completed review of health promotion research. Thematic synthesis has three stages: the coding of text 'line-by-line'; the development of 'descriptive themes'; and the generation of 'analytical themes'. While the development of descriptive themes remains 'close' to the primary studies, the analytical themes represent a stage of interpretation whereby the reviewers 'go beyond' the primary studies and generate new interpretive constructs, explanations or hypotheses. The use of computer software can facilitate this method of synthesis; detailed guidance is given on how this can be achieved. Results We used thematic synthesis to combine the studies of children's views and identified key themes to explore in the intervention studies. Most interventions were based in school and often combined learning about health benefits with 'hands-on' experience. The studies of children's views suggested that fruit and vegetables should be treated in different ways, and that messages should not focus on health warnings. Interventions that were in line with these suggestions tended to be more effective. Thematic synthesis enabled us to stay 'close' to the results of the primary studies, synthesising them in a transparent way, and facilitating the explicit production of new concepts and hypotheses. Conclusion We compare thematic synthesis to other methods for the synthesis of qualitative research, discussing issues of context and rigour. Thematic synthesis is presented as a tried and tested method that preserves an explicit and transparent link between conclusions and the text of primary studies; as such it preserves principles that have traditionally been important to systematic reviewing. PMID:18616818

Comparison of RF spectrum prediction methods for dynamic spectrum access

NASA Astrophysics Data System (ADS)

Kovarskiy, Jacob A.; Martone, Anthony F.; Gallagher, Kyle A.; Sherbondy, Kelly D.; Narayanan, Ram M.

2017-05-01

Dynamic spectrum access (DSA) refers to the adaptive utilization of today's busy electromagnetic spectrum. Cognitive radio/radar technologies require DSA to intelligently transmit and receive information in changing environments. Predicting radio frequency (RF) activity reduces sensing time and energy consumption for identifying usable spectrum. Typical spectrum prediction methods involve modeling spectral statistics with Hidden Markov Models (HMM) or various neural network structures. HMMs describe the time-varying state probabilities of Markov processes as a dynamic Bayesian network. Neural Networks model biological brain neuron connections to perform a wide range of complex and often non-linear computations. This work compares HMM, Multilayer Perceptron (MLP), and Recurrent Neural Network (RNN) algorithms and their ability to perform RF channel state prediction. Monte Carlo simulations on both measured and simulated spectrum data evaluate the performance of these algorithms. Generalizing spectrum occupancy as an alternating renewal process allows Poisson random variables to generate simulated data while energy detection determines the occupancy state of measured RF spectrum data for testing. The results suggest that neural networks achieve better prediction accuracy and prove more adaptable to changing spectral statistics than HMMs given sufficient training data.