共查询到20条相似文献,搜索用时 31 毫秒
1.
Michael Noyong Buelent Ceyhan Christof M. Niemeyer Ulrich Simon 《Colloid and polymer science》2006,284(11):1265-1273
The formation and the optical features of two-dimensional aggregates formed by DNA-directed immobilization and cross-linking of bifunctional DNA–gold nanoparticles at flat gold substrates are analyzed. The samples are structurally characterized by atomic force microscopy to evaluate the particle size, the particle densities, and the degree of aggregation. The optical characteristics determined by UV/visible measurements are correlated with the structural features observed.
相似文献
Ulrich SimonEmail: |
2.
Yan Gao Sabrina Reischmann Johannes Huber Tobias Hanke Rudolf Bratschitsch Alfred Leitenstorfer Stefan Mecking 《Colloid and polymer science》2008,286(11):1329-1334
Single semiconductor quantum dots were embedded into polymer particles with diameters below 0.1 μm by an emulsion polymerization
procedure or via a secondary dispersion approach. The photoluminescence properties of the nanocrystals are retained upon encapsulation,
as demonstrated by fluorescence confocal microscopy.
相似文献
Stefan MeckingEmail: |
3.
Micah Newman 《Foundations of Chemistry》2008,10(1):49-62
This paper surveys some ways in which the chemical realm can be described and outlined in terms of the concept of supervenience.
The particular contours of general chemical theory provide a ready basis for interpretation of determination, covariance,
and nonreduction—the characteristic metaphysical facets of the supervenience relation—in mutual terms. Building on this, the
extent to which chemically characterized properties and entities can be described in terms of a supervenience-scaffolded structure
represents a particularly vivid application that philosophers in general interested in supervenience would do well to attend
to. In addition, the model of chemical supervenience given here can be used as a rubric on which to decide on issues already
raised by philosophers of chemistry.
相似文献
Micah NewmanEmail: |
4.
Partition layer-modified substrates for reversible surface-enhanced Raman scattering detection of polycyclic aromatic hydrocarbons 总被引:1,自引:0,他引:1
Courtney L. Jones Kyle C. Bantz Christy L. Haynes 《Analytical and bioanalytical chemistry》2009,394(1):303-311
Herein, we present progress towards an analytical sensor for polycyclic aromatic hydrocarbons (PAHs) using surface-enhanced
Raman scattering (SERS) on partition layer-modified nanostructured substrates. Specifically, a 1-decanethiol monolayer has
been assembled on a silver film over nanospheres substrate to concentrate PAHs within the zone of SERS detection. Both anthracene
and pyrene were detected with limits of detection at 300 and 700 pM, respectively. The measured SERS spectra allowed for easy
distinction of the two PAH compounds, due to varying peak locations, and insight into the partitioning mechanism. Additionally,
exposure to a common environmental interferant, Suwannee River fulvic acid, did not impede the measurement of the PAHs, and
the sensor is reusable after a short exposure to 1-octanol. Finally, the utility of this sensing platform for PAH detection
was compared to that achievable for other classes of organic pollutants such as polychlorinated biphenyls and polybrominated
diphenyl ethers.
Figure SERS detection of polycyclic aromatic hydrocarbons facilitated via partition layer modified substrates.
相似文献
Christy L. HaynesEmail: |
5.
Fatemeh Hashemzadeh M. Mehdi Kashani Motlagh Amir Maghsoudipour 《Journal of Sol-Gel Science and Technology》2009,51(2):169-174
In this work, MnO2 nanostructure powders with different crystalline phases have been successfully prepared by hydrothermal and sol–gel methods.
The obtained products were characterized by XRD and SEM techniques and their crystallographic phases and morphological properties
compared. Results showed that α-MnO2, β-MnO2, and δ-MnO2 nanorods were synthesized by hydrothermal method and γ-MnO2 polymorph was obtained by sol–gel method.
相似文献
Amir MaghsoudipourEmail: |
6.
Michael Thompson 《Accreditation and quality assurance》2008,13(8):479-482
The currently recommended design of collaborative trials (interlaboratory method performance studies) is examined in relation
to the usefulness of the resulting statistics. It is suggested that larger experiments, without duplicate analysis, would
be more informative.
相似文献
Michael ThompsonEmail: |
7.
Hinne Hettema 《Foundations of Chemistry》2008,10(2):135-142
Michael Weisberg’s recent 2007 paper on the chemical bond makes the claim that the chemical notion of the covalent bond is
in trouble. This note casts doubts on that claim.
相似文献
Hinne HettemaEmail: |
8.
9.
Guy Yardeni Israel Zilbermann Eric Maimon Haim Cohen Dan Meyerstein 《Research on Chemical Intermediates》2009,35(4):543-554
A new CeIII complex was synthesized by mixing the ligand “dioxocyclam” with CeIII ions at pH 8.0 and its redox properties were investigated.
相似文献
Dan Meyerstein (Corresponding author)Email: |
10.
Vaporization enthalpies for the isomeric diazines were discussed within the context of recent measurements and estimation
techniques. It is suggested that pyridazine shows enigmatic behavior.
相似文献
Joel F. Liebman (Corresponding author)Email: |
11.
Edgar D. Goluch Bernhard Wolfrum Pradyumna S. Singh Marcel A. G. Zevenbergen Serge G. Lemay 《Analytical and bioanalytical chemistry》2009,394(2):447-456
Amperometric detection is ideally suited for integration into micro- and nanofluidic systems as it directly yields an electrical
signal and does not necessitate optical components. However, the range of systems to which it can be applied is constrained
by the limited sensitivity and specificity of the method. These limitations can be partially alleviated through the use of
redox cycling, in which multiple electrodes are employed to repeatedly reduce and oxidize analyte molecules and thereby amplify
the detected signal. We have developed an interdigitated electrode device that is encased in a nanofluidic channel to provide
a hundred-fold amplification of the amperometric signal from paracetamol. Due to the nanochannel design, the sensor is resistant
to interference from molecules undergoing irreversible redox reactions. We demonstrate this selectivity by detecting paracetamol
in the presence of excess ascorbic acid.
Figure
相似文献
Serge G. LemayEmail: |
12.
René Dybkaer 《Accreditation and quality assurance》2007,12(12):661-663
Terminology within a small laboratory community can be informal without danger of misunderstanding, but communication with
a wider audience and not least in publications, needs unequivocal terms for defined concepts. As an example, the many meanings
of “concentration” are explored to present a systematic nomenclature, including a concept diagram.
相似文献
René Dybkaer |
13.
The discovery and use of fluorescent proteins has revolutionized cellular biology. Despite the widespread use of visible fluorescent
proteins as reporters and sensors in cellular environments the versatile photophysics of fluorescent proteins is still subject
to intense research. Understanding the details of the photophysics of these reporters is essential for accurate interpretation
of the biological and biochemical processes illuminated by fluorescent proteins. Some aspects of the complex photophysics
of fluorescent proteins can only be observed and understood at the single-molecule level, which removes averaging inherent
to ensemble studies. In this paper we review how single-molecule emission detection has helped understanding of the complex
photophysics of fluorescent proteins.
相似文献
Vinod SubramaniamEmail: |
14.
Christian Schramm Beate Rinderer Wolfgang H. Binder Richard Tessadri Heinz Duelli 《Journal of Sol-Gel Science and Technology》2008,45(1):83-88
(3-Triethoxysilylpropyl)succinic anhydride (TESP-SA) is an organo-functional silicon compound that can be converted into a
polysilsesquioxane when it is hydrolyzed and subsequently subjected to a condensation reaction at elevated temperatures (>160 °C).
If this process is performed without sodium hypophosphite (SHP), a hard solid material is obtained. In contrast, the condensation
reaction of TESP-SA in conjunction with SHP results in the formation of a foamed, brittle material with closed macro cells.
The foam was characterized by means of various analytical methods (FT-IR, 29Si MAS NMR, XRD, TG-MS, SEM).
相似文献
Christian SchrammEmail: |
15.
Sweeping and new on-line sample preconcentration techniques in capillary electrophoresis 总被引:1,自引:0,他引:1
Agnes T. Aranas Armando M. GuidoteJr. Joselito P. Quirino 《Analytical and bioanalytical chemistry》2009,394(1):175-185
Sweeping is a powerful on-line sample preconcentration technique that improves the concentration sensitivity of capillary
electrophoresis (CE). This approach is designed to focus the analyte into narrow bands within the capillary, thereby increasing
the sample volume that can be injected, without any loss of CE efficiency. It utilizes the interactions between an additive
[i.e., a pseudostationary phase (PS) or complexing agent] in the separation buffer and the sample in a matrix that is devoid
of the additive used. The accumulation occurs due to chromatographic partitioning, complexation or any interaction between
analytes and the additive through electrophoresis. The extent of the preconcentration is dependent on the strength of interaction
involved. Both charged and neutral analytes can be preconcentrated. Remarkable improvements—up to several thousandfold—in
detection sensitivity have been achieved. This suggests that sweeping is a superior and general approach to on-line sample
preconcentration in CE. The focusing mechanism of sweeping under different experimental conditions and its combination with
other on-line preconcentration techniques are discussed in this review. The recently introduced techniques of transient trapping
(tr-trapping) and analyte focusing by micelle collapse (AFMC) as well as other novel approaches to on-line sample preconcentration
are also described.
相似文献
Joselito P. QuirinoEmail: |
16.
17.
The advent of chemical tools for cellular imaging—from organic dyes to green fluorescent proteins—has revolutionized the fields
of molecular biology and biochemistry. Lanthanide-based probes are a new player in this area, as the last decade has seen
the emergence of the first responsive luminescent lanthanide probes specifically intended for imaging cellular processes.
The potential of these probes is still undervalued by the scientific community. Indeed, this class of probes offers several
advantages over organic dyes and fluorescent proteins. Their very long luminescence lifetimes enable quantitative spatial
determination of the intracellular concentration of an analyte through time-gating measurements. Their emission bands are
very narrow and do not overlap, enabling the simultaneous use of multiple lanthanide probes to quantitatively detect several
analytes without cross-interference. Herein we describe the principles behind the development of this class of probes. Sensors
for a desired analyte can be designed by rationally manipulating the parameters that influence the luminescence of lanthanide
complexes. We will discuss sensors based on varying the number of inner-sphere water molecules, the distance separating the
antenna from the lanthanide ion, the energies of excited states of the antenna, and PeT switches.
相似文献
Valérie C. PierreEmail: |
18.
H. P. Zhang L. C. Yang L. J. Fu Q. Cao D. L. Sun Y. P. Wu R. Holze 《Journal of Solid State Electrochemistry》2009,13(10):1521-1527
Recent progress in studies of several types of core-shell structured electrode materials, including TiO2/C, Si/C, Si/SiO
x
, LiCoO2/C, and LiFePO4/C nanocomposites, including details of their preparation and their electrochemical performance is briefly reviewed. Results
clearly show that the coating shell can effectively prevent the aggregation of the nanosized cores, which are the electrochemically
active materials. In addition, the diffusion coefficients of lithium ions can be increased, and the reversibility of lithium
intercalation and deintercalation is improved. As a result, the cycling behavior is greatly improved. The reviewed results
suggest that core-shell nanocomposites are a good starting point for further development of new promising electrode materials.
相似文献
Y. P. WuEmail: |
R. Holze (Corresponding author)Email: |
19.
Niki Baccile Anna Fischer Beatriz Julián-López David Grosso Clément Sanchez 《Journal of Sol-Gel Science and Technology》2008,47(2):119-123
Core-shell and homogeneous distributions of functionalized cerium oxide nanoparticles within spray-dried mesostructured silica
spheres are achieved by modification of synthesis parameters such as the templating agent and nanoparticle capping functions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Clément Sanchez (Corresponding author)Email: |
20.
Saad Alshehri John Burgess Colin D. Hubbard Christopher J. Jones Amit K. Das 《Transition Metal Chemistry》2008,33(4):417-420
The kinetics of substitution by alcohols and by aniline at [tris(3,5-dimethylpyrazolyl)hydroborato]molybdenum nitrosyl dihalides in toluene solution at 298.2 K and at atmospheric pressure
are reported and interpreted in terms of an associative mechanism.
相似文献
Colin D. HubbardEmail: |