Molecularly imprinted Au nanoparticles composites on Au surfaces for the surface plasmon resonance detection of pentaerythritol tetranitrate, nitroglycerin, and ethylene glycol dinitrate

Molecularly imprinted Au nanoparticles (NPs) composites are generated on Au-coated glass surfaces. The imprinting process involves the electropolymerization of thioaniline-functionalized Au NPs (3.5 nm) on a thioaniline monolayer-modified Au surface in the presence of a carboxylic acid, acting as a template analogue for the respective explosive. The exclusion of the imprinting template from the Au NPs matrix yields the respective imprinted composites. The binding of the analyte explosives to the Au NPs matrixes is probed by surface plasmon resonance spectroscopy, SPR, where the electronic coupling between the localized plasmon of the Au NPs and the surface plasmon wave leads to the amplification of the SPR responses originating from the dielectric changes of the matrixes upon binding of the different explosive materials. The resulting imprinted matrixes reveal high affinities and selectivity toward the imprinted explosives. Using citric acid as an imprinting template, Au NPs matrixes for the specific analysis of pentaerythritol tetranitrate (PETN) or of nitroglycerin (NG) were prepared, leading to detection limits of 200 fM and 20 pM, respectively. Similarly, using maleic acid or fumaric acid as imprinting templates, high-affinity sensing composites for ethylene glycol dinitrate (EGDN) were synthesized, leading to a detection limit of 400 fM for both matrixes.     

Performance optimization of RZ data format in WDM systems using tunable pulse-width management at the transmitter

Tunable pulse-width management is one of the efficient methods to enhance the robustness of return-to-zero (RZ) data formats for long-haul transmission systems. We demonstrate both single channel and 4 /spl times/ 10-Gb/s wavelength-division-multiplexed performance optimization using tunable pulse-width management. Pure RZ single with tunable pulse-width is generated by changing the driving voltages on a phase modulator and the dispersion values of a tunable dispersion element simultaneously according to our simulation results. Varying the pulse width from 50 to 10 ps at the transmitter can almost double the transmission distance with 4% variation in the residual link dispersion.     

Electrically controllable all-fiber PMD emulator using a compact array of thin-film microheaters

An electrically controllable, all-fiber polarization-mode dispersion (PMD) emulator is constructed using thin-film microheaters to temperature tune the birefringence of 30 PM-fiber sections spliced at 45/spl deg/ angles. Compact packaging is achieved by mounting the fiber heaters onto an array of silicon V-grooves. The advantages of this electrically tunable emulator design are low loss, negligible PDL, simple construction, no internal reflections, and no moving parts.     

The dopamine hypothesis of schizophrenia: current status, future prospects

The dopamine hypothesis of schizophrenia is reviewed in the context of recent advances in dopamine research. These include the following: the discovery that there are several subtypes of dopamine receptor, the recognition that the activity of dopamine neurons is controlled by negative feedback systems; insights into the functions of different subsystems of dopamine neurons; the discovery that different subsystems of dopamine neurons interact with one another; and a growing understanding of the functions and mode of operation of the forebrain regions that the dopamine projections innervate. The paper reviews some of the complexities that the dopamine hypothesis has encountered, and continues to encounter, with a particular focus on three issues: the adequacy of our understanding of neuroleptic drug action, the heterogeneity of schizophrenic symptoms and the paucity of direct evidence to support the hypothesis. It is concluded that schizophrenia does not reflect primary abnormalities of dopamine transmission, but probably does reflect abnormalities in systems that have an intimate interaction with the dopamine system. The primary substrates for schizophrenia will probably be found within the major targets of the ascending dopamine projections: the fronto-striato-pallido-thalamic loops, and the limbic structures, such as amygdala and hippocampus, with which the fronto-striatal system interacts.     

High-Resolution Infrared Fourier-Transform Spectroscopy and Rotational Constants of the nu4 Band of BrNO2

In this study, we assessed the influence of three analgesic techniques on postoperative knee rehabilitation after total knee arthroplasty (TKA). Forty-five patients scheduled for elective TKA under general anesthesia were randomly divided into three groups. Postoperative analgesia was provided with i.v. patient-controlled analgesia (PCA) with morphine in Group A, continuous 3-in-1 block in Group B, and epidural analgesia in Group C. Immediately after surgery, the three groups started identical physical therapy regimens. Pain scores, supplemental analgesia, side effects, degree of maximal knee flexion, day of first walk, and duration of hospital stay were recorded. Patients in Groups B and C reported significantly lower pain scores than those in Group A. Supplemental analgesia was comparable in the three groups. Compared with Groups A and C, a significantly lower incidence of side effects was noted in Group B. Significantly better knee flexion (until 6 wk after surgery), faster ambulation, and shorter hospital stay were noted in Groups B and C. However, these benefits did not affect outcome at 3 mo. We conclude that, after TKA, continuous 3-in-1 block and epidural analgesia provide better pain relief and faster knee rehabilitation than i.v. PCA with morphine. Because it induces fewer side effects, continuous 3-in-1 block should be considered the technique of choice. Implications: In this study, we determined that, after total knee arthroplasty, loco-regional analgesic techniques (epidural analgesia or continuous 3-in-1 block) provide better pain relief and faster postoperative knee rehabilitation than i.v. patient-controlled analgesia with morphine. Because it causes fewer side effects than epidural analgesia, continuous 3-in-1 block is the technique of choice.     

A polarization-independent and contrast-ratio-enhancing module for all-optical wavelength shifting using SOA's

We demonstrate a polarization-independent and contrast-ratio-enhancing all-optical wavelength shifting module using polarization-dependent SOA's. When comparing our robust module to a single polarization-dependent SOA wavelength shifter, we reduce the polarization dependence from 3.5-0.5 dB and the contrast-ratio-induced power penalty from 5-1.5 dB when upshifting over 19 nm at 1 Gb/s.     

Ein betriebsnahes mathematisches Modell des Elektro-Schlacke-Umschmelzverfahrens

Beschreibung eines empirischen, mit einer Regressionsanalyse erstellten mathematischen Modells des Elektro-Schlacke-Umschmelzverfahrens. Aussagen über das stationäre Modell mit globalen Beziehungen zwischen Eingangs- und Zielgrößen und Eignung für eine Parameteroptimierung. Angabe der Modellkoeffizienten und Rangfolge des Einflusses der verschiedenen Variablen auf die jeweils betrachtete Ergebnisgröße. Erläuterung der wichtigsten Modellbeziehungen anhand von Bildern und Vergleich mit bekannten Ergebnissen.     

Metal Ion‐Terpyridine‐Functionalized L‐Tyrosinamide Aptamers: Nucleoapzymes for Oxygen Insertion into C?H Bonds and the Transformation of L‐Tyrosinamide into Amidodopachrome

A series of metal ion‐terpyridine‐modified L‐tyrosinamide aptamers (M^{n +} = Cu²⁺ or Fe³⁺) act as enzyme‐mimicking catalysts (nucleoapzymes) for oxygen‐insertion into C? H bonds and the transformation of L‐tyrosinamide into amidodopachrome. The reaction proceeds in the presence of H₂O₂ and coadded L‐ascorbic acid. In one series of experiments, the catalyzed oxidation of L‐tyrosinamide to amidodopachrome by a set of nucleoapzymes consisting of Fe³⁺‐ or Cu²⁺‐terpyridine complexes tethered directly or through a 4 × thymidine (4 × T) bridge, to the 5′‐ or 3′‐end of the 49‐mer L‐tyrosinamide aptamer or to a shorter 23‐mer L‐tyrosinamide aptamer is examined. All nucleoapzymes reveal catalytic Michaelis–Menten enzyme‐like activities and the separated Fe³⁺‐ or Cu²⁺‐terpyridine and L‐tyrosinamide aptamer units show only minute catalytic properties. The catalytic activities of the nucleoapzymes are attributed to the concentration of the L‐tyrosinamide substrate by the aptamer units in proximity to the catalytic sites (K_d = (14 ± 0.1) × 10^?6 m for all 49‐mer catalysts and K_d = (2.5 ± 0.1) × 10^?6 m and K_d = (0.8 ± 0.04) × 10^?6 m for the 23‐mer catalysts). Electron spin resonance experiments reveal that ?OH radicals and ascorbate radicals participate in the transformation of tyrosine derivatives to catechol products. An autocatalytic feedback mechanism for the amplified generation of the two radicals is suggested.