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Insect Species Damage on Ornamental Plants and Saplings of Bartin Province and Its Vicinity in the Western Black Sea Region of Turkey

Kaygin, Azize Toper; Sönmezyildiz, Hilmi; Ülgentürk, Selma; Özdemir, Işıl
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 04/04/2008 EN
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The objectives of this study were to identify harmful insect species, understand their biology, assess their damage potential and target plants and define distribution areas. There are a lot of native or cultured ornamental plants in Bartın and its surrounding (Çaycuma, Zonguldak, Karabük, Mengen, Devrek). These plants are herbaceous and woody species. Specimens were collected from various cultured and non-cultured plants. A total of 34 species belonging to 20 families of 5 orders were identified. The order Hemiptera was represented by the highest number of species (19 species), followed by Coleoptera (8), Lepidoptera (4), Orthoptera (2), and Dermaptera (1). Insect samples were collected from plants by net traps, special insect aspirators, and various insect traps. The identified species have been stored in the collection room of the Forest Entomology and Protection Unit, Bartın Forestry Faculty, Zonguldak Karaelmas University (Z.K.U.), Turkey. This is the first detailed study about insect species causing damage on ornamental plants and saplings of Bartın province and its vicinity, although similar studies of different regions exist. This research makes a very important contribution to the insect fauna of Bartın, its environs and Turkey. Twenty four of the identified species were new for Bartın and its vicinity...

Control of stilbene conformation and fluorescence in self-assembled capsules

Ams, Mark R; Ajami, Dariush; Craig, Stephen L; Yang, Jye-Shane; Rebek, Julius
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 11/12/2009 EN
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The extensively studied trans-stilbene molecule is known to give only weak fluorescence in solution and inside loosely-fitting synthetic capsules. However, trans-stilbene has been recently studied in the context of antibody interiors, where binding results in strong blue fluorescence. The present research was undertaken to understand the spatial factors that influence stilbene fluorescence. trans-Stilbene was encapsulated in the snug, self-assembled complex 1.1 and exhibited fluorescence quenching due to the distortion of its ground-state geometry. When the complex is elongated by incorporating glycouril spacers, trans-stilbene is allowed to adapt a fully coplanar arrangement and fluorescence returns.

Gelation or molecular recognition; is the bis-(α,β-dihydroxy ester)s motif an omnigelator?

Griffiths, Peter C; Knight, David W; Morgan, Ian R; Ford, Amy; Brown, James; Davies, Ben; Heenan, Richard K; King, Stephen M; Dalgliesh, Robert M; Tomkinson, John; Prescott, Stuart; Schweins, Ralf; Paul, Alison
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 18/11/2010 EN
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Understanding the gelation of liquids by low molecular weight solutes at low concentrations gives an insight into many molecular recognition phenomena and also offers a simple route to modifying the physical properties of the liquid. Bis-(α,β-dihydroxy ester)s are shown here to gel thermoreversibly a wide range of solvents, raising interesting questions as to the mechanism of gelation. At gelator concentrations of 5–50 mg ml−1, gels were successfully formed in acetone, ethanol/water mixtures, toluene, cyclohexane and chloroform (the latter, albeit at a higher gelator concentration). A range of neutron techniques – in particular small-angle neutron scattering (SANS) – have been employed to probe the structure of a selection of these gels. The universality of gelation in a range of solvent types suggests the gelation mechanism is a feature of the bis-(α,β-dihydroxy ester) motif, with SANS demonstrating the presence of regular structures in the 30–40 Å range. A correlation between the apparent rodlike character of the structures formed and the polarity of the solvent is evident. Preliminary spin-echo neutron scattering studies (SESANS) indicated the absence of any larger scale structures. Inelastic neutron spectroscopy (INS) studies demonstrated that the solvent is largely unaffected by gelation...

Dense lying self-organized GaAsSb quantum dots on GaAs for efficient lasers

Loeber, Thomas H; Hoffmann, Dirk; Fouckhardt, Henning
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 30/06/2011 EN
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GaAsSb quantum dots (QDs) were grown on GaAs in the Stranski–Krastanov (SK) epitaxial mode. Their characteristics were dependent on the Sb/Ga (V/III) flux ratio and the growth temperature. The samples were grown with a V/III ratio between 0.45/1 and 1.50/1 and a temperature between 445 and 580 °C, not commonly used by other research groups. These parameters enabled the growth of dense lying dots with a density at least up to 6.5 × 1010 cm−2 and a diameter and height of 20 and 4 nm, respectively. The photoluminescence (PL) spectra revealed a QD peak at an emission wavelength between λ = 0.876 and 1.035 μm, depending on the exact conditions. Using a stack of such QD layers, an electrically pumped efficient QD laser was realized with an emission wavelength of λ ≈ 0.900 µm at a temperature of 84 K.

Fabrication of multi-parametric platforms based on nanocone arrays for determination of cellular response

Purwaningsih, Lindarti; Schoen, Tobias; Wolfram, Tobias; Pacholski, Claudia; Spatz, Joachim P
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 06/09/2011 EN
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Cellular response to both surface topography and surface chemistry has been studied for several years. However, most of the studies focus on only one of the two parameters and do not consider their possible synergistic effects. Here, we report on a fabrication method for nanostructured surfaces composed of highly ordered arrays of silica nanocones with gold tips. By using a combination of block copolymer nanolithography, electroless deposition, and reactive ion etching several parameters such as structure height and structure distance could easily be adjusted to the desired values. The gold tips allow for easy functionalization of the substrates through a thiol linker system. Improved neural cell adhesion can be obtained and is dependent on the nature of the nanocone surface, thus illustrating the influence of different surface topographies on the nanometer length scale, on a complex cellular behavior such as cell adhesion. Substrate and surface functionality are shown to last over several days, leading to the conclusion that the features of our substrates can also be used for longer term experiments. Finally, initial neural cell adhesion is found to be more prominent on substrates with short intercone distances, which is an important finding for research dealing with the reactions of neuron-like tissue in the immediate moments after direct contact with an implanted surface.

Distinction of nucleobases – a tip-enhanced Raman approach

Treffer, Regina; Lin, Xiumei; Bailo, Elena; Deckert-Gaudig, Tanja; Deckert, Volker
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 23/09/2011 EN
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The development of novel DNA sequencing methods is one of the ongoing challenges in various fields of research seeking to address the demand for sequence information. However, many of these techniques rely on some kind of labeling or amplification steps. Here we investigate the intrinsic properties of tip-enhanced Raman scattering (TERS) towards the development of a novel, label-free, direct sequencing method. It is known that TERS allows the acquisition of spectral information with high lateral resolution and single-molecule sensitivity. In the presented experiments, single stranded adenine and uracil homopolymers were immobilized on different kinds of substrates (mica and gold nanoplates) and TERS experiments were conducted, which demonstrated the reproducibility of the technique. To elucidate the signal contributions from the specific nucleobases, TERS spectra were collected on single stranded calf thymus DNA with arbitrary sequence. The results show that, while the Raman signals with respect to the four nucleobases differ remarkably, specific markers can be determined for each respective base. The combination of sensitivity and reproducibility shows that the crucial demands for a sequencing procedure are met.

Effect of the tip state during qPlus noncontact atomic force microscopy of Si(100) at 5 K: Probing the probe

Sweetman, Adam; Jarvis, Sam; Danza, Rosanna; Moriarty, Philip
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 09/01/2012 EN
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Background: Noncontact atomic force microscopy (NC-AFM) now regularly produces atomic-resolution images on a wide range of surfaces, and has demonstrated the capability for atomic manipulation solely using chemical forces. Nonetheless, the role of the tip apex in both imaging and manipulation remains poorly understood and is an active area of research both experimentally and theoretically. Recent work employing specially functionalised tips has provided additional impetus to elucidating the role of the tip apex in the observed contrast.

The morphology of silver nanoparticles prepared by enzyme-induced reduction

Schneidewind, Henrik; Schüler, Thomas; Strelau, Katharina K; Weber, Karina; Cialla, Dana; Diegel, Marco; Mattheis, Roland; Berger, Andreas; Möller, Robert; Popp, Jürgen
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 18/05/2012 EN
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Silver nanoparticles were synthesized by an enzyme-induced growth process on solid substrates. In order to customize the enzymatically grown nanoparticles (EGNP) for analytical applications in biomolecular research, a detailed study was carried out concerning the time evolution of the formation of the silver nanoparticles, their morphology, and their chemical composition. Therefore, silver-nanoparticle films of different densities were investigated by using scanning as well as transmission electron microscopy to examine their structure. Cross sections of silver nanoparticles, prepared for analysis by transmission electron microscopy were additionally studied by energy-dispersive X-ray spectroscopy in order to probe their chemical composition. The surface coverage of substrates with silver nanoparticles and the maximum particle height were determined by Rutherford backscattering spectroscopy. Variations in the silver-nanoparticle films depending on the conditions during synthesis were observed. After an initial growth state the silver nanoparticles exhibit the so-called desert-rose or nanoflower-like structure. This complex nanoparticle structure is in clear contrast to the auto-catalytically grown spherical particles, which maintain their overall geometrical appearance while increasing their diameter. It is shown...

Active motif finder - a bio-tool based on mutational structures in DNA sequences

Udayakumar, Mani; Shanmuga-priya, Palaniyandi; Hemavathi, Kamalakannan; Seenivasagam, Rengasamy
Fonte: Editorial Department of Journal of Biomedical Research Publicador: Editorial Department of Journal of Biomedical Research
Tipo: Artigo de Revista Científica
Publicado em /11/2011 EN
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Active Motif Finder (AMF) is a novel algorithmic tool, designed based on mutations in DNA sequences. Tools available at present for finding motifs are based on matching a given motif in the query sequence. AMF describes a new algorithm that identifies the occurrences of patterns which possess all kinds of mutations like insertion, deletion and mismatch. The algorithm is mainly based on the Alignment Score Matrix (ASM) computation by comparing input motif with full length sequence. Much of the effort in bioinformatics is directed to identify these motifs in the sequences of newly discovered genes. The proposed bio-tool serves as an open resource for analysis and useful for studying polymorphisms in DNA sequences. AMF can be searched via a user-friendly interface. This tool is intended to serve the scientific community working in the areas of chemical and structural biology, and is freely available to all users, at http://www.sastra.edu/scbt/amf/.

Development of a Molecularly Imprinted Biomimetic Electrode

Kindschy, Lisa M.; Alocilja, Evangelyn C.
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 27/08/2007 EN
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The technique of molecular imprinting produces artificial receptor sites in a polymer that can be used in a biomimetic sensor. This research extends previous studies of a molecularly imprinted polymer (MIP) biomimetic sensor for the small drug theophylline. The presence of theophylline in the biomimetic sensor was monitored by analyzing the peak currents from cyclic voltammetry experiments. The functional working range of the MIP modified electrode was 2 - 4 mM theophylline. The concentration of theophylline that resulted in the best signal was 3 mM. The MIP sensor showed no response to the structurally related molecule caffeine, and therefore was selective to the target analyte theophylline. This research will provide the foundation for future studies that will result in durable biomimetic sensors that can offer a viable alternative to current sensors.

Effect of Estimated Daily Global Solar Radiation Data on the Results of Crop Growth Models

Trnka, Miroslav; Eitzinger, Josef; Kapler, Pavel; Dubrovský, Martin; Semerádová, Daniela; Žalud, Zden ěk; Formayer, Herbert
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 16/10/2007 EN
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The results of previous studies have suggested that estimated daily global radiation (RG) values contain an error that could compromise the precision of subsequent crop model applications. The following study presents a detailed site and spatial analysis of the RG error propagation in CERES and WOFOST crop growth models in Central European climate conditions. The research was conducted i) at the eight individual sites in Austria and the Czech Republic where measured daily RG values were available as a reference, with seven methods for RG estimation being tested, and ii) for the agricultural areas of the Czech Republic using daily data from 52 weather stations, with five RG estimation methods. In the latter case the RG values estimated from the hours of sunshine using the Ångström-Prescott formula were used as the standard method because of the lack of measured RG data. At the site level we found that even the use of methods based on hours of sunshine, which showed the lowest bias in RG estimates, led to a significant distortion of the key crop model outputs. When the Ångström-Prescott method was used to estimate RG, for example, deviations greater than ±10 per cent in winter wheat and spring barley yields were noted in 5 to 6 per cent of cases. The precision of the yield estimates and other crop model outputs was lower when RG estimates based on the diurnal temperature range and cloud cover were used (mean bias error 2.0 to 4.1 per cent). The methods for estimating RG from the diurnal temperature range produced a wheat yield bias of more than 25 per cent in 12 to 16 per cent of the seasons. Such uncertainty in the crop model outputs makes the reliability of any seasonal yield forecasts or climate change impact assessments questionable if they are based on this type of data. The spatial assessment of the RG data uncertainty propagation over the winter wheat yields also revealed significant differences within the study area. We found that RG estimates based on diurnal temperature range or its combination with daily total precipitation produced a bias of to 30 per cent in the mean winter wheat grain yields in some regions compared with simulations in which RG values had been estimated using the Ångström-Prescott formula. In contrast to the results at the individual sites...

Scale effects of nanomechanical properties and deformation behavior of Au nanoparticle and thin film using depth sensing nanoindentation

Maharaj, Dave; Bhushan, Bharat
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 11/06/2014 EN
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Nanoscale research of bulk solid surfaces, thin films and micro- and nano-objects has shown that mechanical properties are enhanced at smaller scales. Experimental studies that directly compare local with global deformation are lacking. In this research, spherical Au nanoparticles, 500 nm in diameter and 100 nm thick Au films were selected. Nanoindentation (local deformation) and compression tests (global deformation) were performed with a nanoindenter using a sharp Berkovich tip and a flat punch, respectively. Data from nanoindentation studies were compared with bulk to study scale effects. Nanoscale hardness of the film was found to be higher than the nanoparticles with both being higher than bulk. Both nanoparticles and film showed increasing hardness for decreasing penetration depth. For the film, creep and strain rate effects were observed. In comparison of nanoindentation and compression tests, more pop-ins during loading were observed during the nanoindentation of nanoparticles. Repeated compression tests of nanoparticles were performed that showed a strain hardening effect and increased pop-ins during subsequent loads.

Working Principle Simulations of a Dynamic Resonant Wall Shear Stress Sensor Concept

Zhang, Xu; Naughton, Jonathan W.; Lindberg, William R.
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 17/04/2008 EN
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This paper discusses a novel dynamic resonant wall shear stress sensor concept based on an oscillating sensor operating near resonance. The interaction between the oscillating sensor surface and the fluid above it is modelled using the unsteady laminar boundary layer equations. The numerical experiment shows that the effect of the oscillating shear stress is well correlated by the Hummer number, the ratio of the steady shear force caused by the outside flow to the oscillating viscous force created by the sensor motion. The oscillating shear stress predicted by the fluid model is used in a mechanical model of the sensor to predict the sensor's dynamic motion. Static calibration curves for amplitude and frequency influences are predicted. These results agree with experimental results on some extent, and shows some expectation for further development of the dynamic resonant sensor concept.

Intercomparison of Evapotranspiration Over the Savannah Volta Basin in West Africa Using Remote Sensing Data

Opoku-Duah, S.; Donoghue, D.N.M.; Burt, T. P.
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 17/04/2008 EN
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This paper compares evapotranspiration estimates from two complementary satellite sensors – NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) and ESA's ENVISAT Advanced Along-Track Scanning Radiometer (AATSR) over the savannah area of the Volta basin in West Africa. This was achieved through solving for evapotranspiration on the basis of the regional energy balance equation, which was computationally-driven by the Surface Energy Balance Algorithm for Land algorithm (SEBAL). The results showed that both sensors are potentially good sources of evapotranspiration estimates over large heterogeneous landscapes. The MODIS sensor measured daily evapotranspiration reasonably well with a strong spatial correlation (R2=0.71) with Landsat ETM+ but underperformed with deviations up to ∼2.0 mm day-1, when compared with local eddy correlation observations and the Penman-Monteith method mainly because of scale mismatch. The AATSR sensor produced much poorer correlations (R2=0.13) with Landsat ETM+ and conventional ET methods also because of differences in atmospheric correction and sensor calibration over land.

Hardware and Software of a Bipolar Current Source Controlled by PC

Milivojević, Dragan; Stević, Zoran; Rajčić-Vujasinović, Mirjana
Fonte: Molecular Diversity Preservation International (MDPI) Publicador: Molecular Diversity Preservation International (MDPI)
Tipo: Artigo de Revista Científica
Publicado em 22/03/2008 EN
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This paper describes a realization of a bipolar current source developed by the paper's authors. The source is intended for use in galvanic and other industrial plants, where a pulse-reverse current supply (with the desired shape in time) is required. A prototype of the device, which provides the outcome current intensity up to ± 50 A, has been constructed. The hardware of the source consists of a Pentium IV PC, a commercial ADDA converter, an interface of authors' original construction as well as a current regulator. The application software is developed using a commercial packet LabView as the basis.

Predicting cytotoxicity of PAMAM dendrimers using molecular descriptors

Jones, David E; Ghandehari, Hamidreza; Facelli, Julio C
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 11/09/2015 EN
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The use of data mining techniques in the field of nanomedicine has been very limited. In this paper we demonstrate that data mining techniques can be used for the development of predictive models of the cytotoxicity of poly(amido amine) (PAMAM) dendrimers using their chemical and structural properties. We present predictive models developed using 103 PAMAM dendrimer cytotoxicity values that were extracted from twelve cancer nanomedicine journal articles. The results indicate that data mining and machine learning can be effectively used to predict the cytotoxicity of PAMAM dendrimers on Caco-2 cells.

High I on/I off current ratio graphene field effect transistor: the role of line defect

Tajarrod, Mohammad Hadi; Saghai, Hassan Rasooli
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 23/10/2015 EN
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The present paper casts light upon the performance of an armchair graphene nanoribbon (AGNR) field effect transistor in the presence of one-dimensional topological defects. The defects containing 5–8–5 sp2-hybridized carbon rings were placed in a perfect graphene sheet. The atomic scale behavior of the transistor was investigated in the non-equilibrium Green's function (NEGF) and tight-binding Hamiltonian frameworks. AGNRFET basic terms such as the on/off current, transconductance and subthreshold swing were investigated along with the extended line defect (ELD). The results indicated that the presence of ELDs had a significant effect on the parameters of the GNRFET. Compared to conventional transistors, the increase of the I on/I off ratio in graphene transistors with ELDs enhances their applicability in digital devices.

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

Garcias-Morales, Cesar; Ortegón-Reyna, David; Ariza-Castolo, Armando
Fonte: Beilstein-Institut Publicador: Beilstein-Institut
Tipo: Artigo de Revista Científica
Publicado em 22/10/2015 EN
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This paper reports the synthesis of a series of piperidones 1–8 by the Mannich reaction and analysis of their structures and conformations in solution by NMR and mass spectrometry. The six-membered rings in 2,4,6,8-tetraphenyl-3,7-diazabicyclo[3.3.1]nonan-9-ones, compounds 1 and 2, adopt a chair–boat conformation, while those in 2,4-diphenyl-3-azabicyclo[3.3.1]nonan-9-ones, compounds 3–8, adopt a chair–chair conformation because of stereoelectronic effects. These stereoelectronic effects were analyzed by the 1 J C–H coupling constants, which were measured in the 13C satellites of the 1H NMR spectra obtained with the hetero-dqf pulse sequence. In the solid state, these stereoelectronic effects were investigated by measurement of X-ray diffraction data, the molecular geometry (torsional bond angles and bond distances), and inter- and intramolecular interactions, and by natural bond orbital analysis, which was performed using density functional theory at the ωB97XD/6311++G(d,p) level. We found that one of the main factors influencing the conformational stability of 3–8 is the interaction between the lone-pair electrons of nitrogen and the antibonding sigma orbital of C(7)–Heq (nN→σ*C–H(7)eq), a type of hyperconjugative interaction.

Research in Latin America

Crisis States Research Centre,
Fonte: Crisis States Research Centre, London School of Economics and Political Science Publicador: Crisis States Research Centre, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf; application/pdf
Publicado em /04/2001 EN; EN; EN
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This paper provides full details of the Crisis States Programme in Latin America.

States of crisis in India: comparative research in Bihar and Madhya Pradesh

Crisis States Research Centre,
Fonte: Crisis States Research Centre, London School of Economics and Political Science Publicador: Crisis States Research Centre, London School of Economics and Political Science
Tipo: Monograph; NonPeerReviewed Formato: application/pdf
Publicado em /04/2001 EN; EN
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This paper provides full details of the Crisis States Programme in South Asia. It includes a short essay on "Political Ethnography".