Au nanoparticle micropatterns prepared from self-assembled films

A kind of hybrid multilayer film based on mercaptobenzoic acid-capped Au nanoparticles (MBA-Au-NPs) and photoreactive nitrodiazoresin (NDR) has been fabricated via electrostatic self-assembly. Upon exposure to UV light, the initial ionic bonds between the layers of the film convert into covalent bonds and the film stability toward polar solvents, salt, or surfactant solutions increases significantly. The micropatterned NDR/MBA-Au-NP film with the covalently linked architecture was formed by selecting exposure of the film through a photomask and later developed in sodium dodecyl sulfate (SDS) aqueous solution. The metallic Au-NP micropatterns, furthermore, are produced by sintering the micropatterned NDR/MBA-Au-NP film at 550 degrees C, at which the organic components are removed completely. The well-defined micropatterns were characterized with atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), microscope with a charge-coupled device (CCD) camera, and X-ray photoelectron spectroscopy (XPS).     

Prototype of immunochromatographic assay strips using colloidal CdTe nanocrystals as biological luminescent label

Colloidal semiconductor nanocrystals have attracted considerable attention as a novel biological luminescent label. The bioinorganic conjugates of luminescent CdTe nanocrystals and protein, including CdTe/BSA (bovine serum albumin) and CdTe/MAB (mouse monoclonal antibody against hepatities B surface antigen), were formed via electrostatic/coordination self-assembly. Pure CdTe nanocrystals, CdTe/BSA and CdTe/MAB were used in the immunochromatographic assay experiments, respectively. And the results indicated that CdTe nanocrystals could be used and developed as a novel label with good stability, high sensitivity and facile determination of several analytes in immunochromatographic assay strips.     

O-二异丙氧磷酰基丝氨酸(或苏氨酸或酪氨酸)的合成

介绍一种简单方便地合成O-二异丙氧磷酰基丝氨酸(或苏氨酸或酪氨酸)的方法.其中O-二异丙氧磷酰基-L-丝氨酸(或苏氨酸)可从对应的N-磷酰化-L-丝氨酸(或苏氨酸)利用磷酰基N→0迁移的性质并在超声辅助下合成,而N-二异丙氧磷酰基-L-丝氨酸(或苏氨酸)的合成由L-丝氨酸(或苏氨酸)在次氯酸钠的水溶液中高收率地获得.O-二异丙氧磷酰基酪氨酸的合成可通过铜盐同时保护氨基和羧基,使用二异丙基磷酰氯为磷酰化试剂磷酰化,用硫化氢脱铜保护制备.     

Classical Dynamics of H<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack> in an Intense Laser Field by Using the Symplectic Method

The classical dynamics of 1D H₂⁺ in an intense field are discussed. The initial conditions are chosen at random in the field-free case, and then the Hamiltonian canonical equations of H₂⁺ system in the intense laser field are solved numerically by mean of the symplectic method under these initial conditions. The probabilities of survival, dissociation, ionization, and Coulomb explosion of H₂⁺ system in the intense laser field are obtained for different laser intensity based on the classical theory.     

Preparation, characterization and properties studies of quinine-imprinted polymer in the aqueous phase

The uniform-sized spherical molecularly imprinted polymers were successfully prepared through molecular imprinting technology by two-step seed swelling and mini-emulsion polymerization in the aqueous condition using quinine as template molecules and methacrylic acid (MAA) as functional monomer. The polymers were characterized by IR spectra, thermal-weight analysis, scanning electron microscope and laser particle size analysis. The properties of imprinted polymers were investigated in different organic phases and aqueous media. In the organic media, results suggested that polar interactions (hydrogen bonding, ionic interactions) between acidic monomer/polymer and template molecules are mainly responsible for the binding and recognition; whereas in the aqueous medium, a considerable recognition effect was also obtained where the ionic (electrostatic) interaction and hydrophobic interaction play an important role. The experiments of binding different substrates indicated that the MIPs possessed an excellent rebinding ability and inherent selectivity to quinine. __________ Translated from Zhongshan Dcocue Xuebao/Acta Scientianum Natralium University Sunyatseni, 2005, 44(3)(in Chinese)     

Synthesis and structural identification of a highly ordered mesoporous organosilica with large cagelike pores

Using 1,2-bis(trimethoxysilyl)ethane as organosiloxane precursor and a triblock copolymer surfactant, Pluronic F127, as template, a highly ordered mesoporous organosilica with large cagelike pores has been successfully synthesized. Its structure was resolved to be 3-D cubic Fmm by high-resolution transmission electron microscopy. The intergrowth of hexagonal close-packed and cubic close-packed phases was observed in this material. The effect of different siliceous precursors on the mesostructure was also investigated.     

Co-C bond dissociation energy and reaction volume change of 2',5'-dideoxyadenosylcobalamin studied by laser-induced time-resolved photoacoustic calorimetry

Time resolved photoacoustic calorimetry (PAC) was applied to a study of the photolysis of a coenzyme B(12) analog 2',5'-dideoxyadenosylcobalamin, which lacks an -OH group at the 2' position of ribofuranose ring. In aqueous solution, we report for the first time the quantum yield Phi(d) (0.25+/-0.02), Co-C bond dissociation energy (BDE; 31.8+/-2.5 kcal mol(-1)) and reaction volume change deltaV(R) (6.5+/-0.5 ml mol(-1)) due to conformation changes of the corrin ring and its side chains accompanying the cleavage of the Co-C bond. These values for the analog are very similar to those for the natural cofactor. Based our results and previous studies, a possible explanation for the similarity in their structure and properties versus the large difference in their enzymatic activity is discussed.     

An Investigation on the Production of Random Copolymer with Monothiocarbonate and Trithiocarbonate Units over Cyclic Thiocarbonate via Metal‐free Catalysis

Synthesis of poly(thiocarbonate)s from the copolymerization of epoxides and carbon disulfide (CS₂) remains a tough challenge, due to inevitable oxygen‐sulfur atom scrambling process. In this work, we utilized the oxygen‐sulfur exchange reaction (O‐S ER) to synthesize a random copolymer with monothiocarbonate and trithiocarbonate units from CS₂ and phenyl glycidyl ether (PGE) via metal‐free Lewis pairs. The copolymers contained monothiocarbonate and trithiocarbonate units of which the molar fraction could be tuned by varying either the types of Lewis pairs or the reaction temperature. Keeping track on the intermediate provided an insight in the process of O‐S ER and thus gave a hint to control the product structure. Production and consumption of phenyl thioglycidyl ether was the key process to regulate the chain structure. Remarkably, the oxygen atoms of PGE could be excluded out of the chain, resulting in the nearly complete production of poly(trithiocarbonate)s. Correspondingly, the refractive index of this kind of copolymer could be regulated in a wide range of 1.73—1.79 (at 590 nm).     

Synthesis of a Novel Type of Phosphates of Puerarin

A novel type of phosphated puerarin derivatives were synthesized through a simplified Atheron‐Todd reaction for the first time. The structure of these compounds were elucidated by IR, ESI‐MS and NMR. Moreover, the reason the dialkylphophite reagent had different chemselectivities toward different hydroxys on the puerarin was discussed.     

Atomabsorptions-Flammenphotometrie im Einstrahlverfahren mit Kompensation der von Flamme und Hintergrundstrahler verursachten Schwankungen

Zusammenfassung Es wird gezeigt, daß auch im Einstrahlverfahren sogar extrem starke Schwankungen der Betriebsparameter der Flamme (Brenngas- und Preßluftdruck, Probendurchsatz) aus dem Meßergebnis weitgehend eliminiert werden können, wenn hinreichend oft Zwischeneichungen vorgenommen werden. Auf die gleiche Weise kann man selbstverständlich auch zeitliche Änderungen der Emission des Hintergrundstrahlers ausschalten. Für die Voruntersuchungen wurde ein aus handelsüblichen Bauteilen zusammengestelltes Gerät benutzt, welches mehr als 15 Zwischeneichungen pro Minute zuläßt. Dabei zeigte sich unter anderem, daß eine Änderung des Probendurchsatzes um den Faktor 10 (innerhalb 1 min) eine Änderung des Extinktionswertes der Probe um den Faktor 4 (also 400%) zur Folge hat. Dagegen beträgt in dieser Meßreihe die größte beobachtete Abweichung einer Einzelmessung des Extinktionsverhältnisses Analysenlösung/Eichlösung vom Mittelwert nur 22%. Abschließend wird ein in der Entwicklung befindliches und weitgehend automatisiertes Gerät vorgeschlagen, welches wesentlich bessere Ergebnisse erwarten läßt.

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Summary It is shown that even for atomic-absorption analyses with a single-beam instrument, the values measured will be essentially independent on large fluctuations in the operating conditions of the flame (gas pressures and sample flow rate), if the standard measurement made after every sample measurement is repeated often enough. Naturally, with the same technique the variation of emission from the discharge lamp will also not affect the analytical results. For the first experiments an instrument composed of commercially available components was used. It allowed the sample solution and standard solution to be alternately aspirated more than 15 times per minute. It was observed that the extinction value for the sample solution changed by a factor of 4 (that is 400%) when the sample flow rate changed by a factor of 10 (within a minute). On the other hand, in this series of measurements the gratest deviation observed between a single value for the ratio of sample solution extinction/standard solution extinction and the average value amounted to only 22%. Finally, an essentially automatic instrument being developed is proposed. With this instrument considerably better results can be expected.

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Herrn Prof. Dr. R. Herrmann möchte ich auch an dieser Stelle meinen Dank aussprechen für sein reges Interesse am Fortgang der Arbeit und für die kritische Durchsicht des Manuskriptes. Fräulein B. Gutsche danke ich für die Mitarbeit bei der Durchführung und Auswertung der Messungen.