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Time domain investigation of the intrachain vibrational dynamics of a prototypical light-emitting conjugated polymer.

Coherent nuclear motion of the carbon backbone is monitored in real time in substituted poly(phenylene)-vinylene in both excited and ground electronic state using sub-10-fs light pulses. Characteristic features of the intrachain vibrational dynamics are obtained. We observe vibrational dephasing in the excited state within 1 ps (time constant T(2e) approximately 300 fs). These findings are in agreement with the molecular picture for photoexcitation in conjugated polymers.

Journal Article↗

High-resolution spectroscopy of NO in helium droplets: a prototype for open shell molecular interactions in a quantum solvent.

We have measured the high-resolution infrared spectrum of the radical NO in the (2)Pi(1/2) state in superfluid helium nanodroplets. The features are attributed to the -doubling splitting and the hyperfine structure. The hyperfine interaction is found to be unaffected by the He solvation. For the Lambda-doubling splitting, we find a considerable increase by 55% compared to the gas phase. This is explained by a confinement of the electronically excited NO states by the surrounding He. The rotational level spacing is decreased to 76% of the gas phase value. The IR transition to the J=1.5 state is found to be homogeneously broadened. We attribute both observations to the coupling between the molecular rotation and phonon/roton excitations in superfluid (4)He droplets.

Journal Article↗

Operation of an X-ray undulator in the Tristan main ring as a prototype of future super light sources.

A 5.4 m-long 239-pole undulator comprising three rigid and precise standardized-unit undulators was completed and installed in the Tristan main ring, which was operated as a light source at a beam energy from 8 to 10 GeV. This undulator was successfully tested, characterized and used as a brilliant hard X-ray source for several synchrotron radiation experiments during the last 3.5 months of 1995.

Journal Article↗

Prototyping: a key to managing product development.

Extended development cycles put companies at risk through loss of sales, margins, market share, and credibility as innovators. The author suggests constructing early-stage models to provide a dress rehearsal for new products and help companies develop products in less time.

Cost-Benefit Analysis↗

A new concept toward computer-aided medical diagnosis--a prototype implementation addressing pulmonary diseases.

The original concept that led to the structuring of a computer-based medical decision support system (DSS) that is able to support a physician's diagnosis is introduced in this paper. The concept's implementation modeled a generic DSS, the core of which are an integrated knowledge/information base (KIB) along with the inference properties of a data evaluator. The KIB encapsulates the necessary medical knowledge and experience in the form of rules and constraints, preemptive tasks, and actual patients' clinical data. The data evaluator handles approved medical subjective and objective criteria for assessing the KIB's data. The data evaluator incorporates a medical standard data gathering and decision process, structured upon the principles of the clinical differential diagnosis methodology and has been integrated in the system by means of both algorithmic and artificial intelligence techniques. The novel model and the resulted computer-based package have been extensively tested under the Pulmonary Department, University Regional Hospital Patras, Patras, Greece.

Artificial Intelligence↗

Computer-aided prototype system for nose surgery.

Rhinoplasty, or surgery to reshape the nose, is one of the most common of all plastic-surgery procedures. Rhinoplasty can enhance a patient's appearance and self-confidence, may also correct a birth defect or injury, or help relieve some breathing problem. In this paper, we present a three-dimensional (3-D) surgical simulation system, which can assist surgeons in planning rhinoplasty procedures. This system employs computer graphics and image-processing techniques for the simulation of a rhinoplasty. Although the presented algorithms themselves are not new, the proposed system exploits the new idea to apply 3-D morphing for rhinoplasty, and simulation results are useful for the physicians. According to patients' expectation of what they would like their noses to look like, our system simulates expected results. Our tools provide quantitative measurements of a nose structure. Using these quantitative results, surgeons can arrange appropriate preoperative plans for patients. Finally, experimental results and experiences are reported to evaluate the usefulness of the proposed system.

Computer Simulation↗

Prediction of care class by local additive reference to prototypical examples.

The public long-term care insurance program for the elderly in Japan set out in 2000 toward establishing a new system whereby citizens can be assured that they will receive care and be supported by the society as a whole. The insurance program includes computer-aided certification processes to estimate the needs for nursing care for clients. In this work, we show the applicability of an adaptive local nonlinear approximation method associated with the Japanese national database for automatic inference of the care class.

Aged↗

Learning lateral interactions for feature binding and sensory segmentation from prototypic basis interactions.

We present a hybrid learning method bridging the fields of recurrent neural networks, unsupervised Hebbian learning, vector quantization, and supervised learning to implement a sophisticated image and feature segmentation architecture. This architecture is based on the competitive layer model (CLM), a dynamic feature binding model, which is applicable on a wide range of perceptual grouping and segmentation problems. A predefined target segmentation can be achieved as attractor states of this linear threshold recurrent network, if the lateral weights are chosen by Hebbian learning. The weight matrix is given by the correlation matrix of special pattern vectors with a structure dependent on the target labeling. Generalization is achieved by applying vector quantization on pair-wise feature relations, like proximity and similarity, defined by external knowledge. We show the successful application of the method to a number of artifical test examples and a medical image segmentation problem of fluorescence microscope cell images.

Image Processing, Computer-Assisted↗

A novel sensor for monitoring acoustic cavitation. Part I: Concept, theory, and prototype development.

This paper describes a new concept for an ultrasonic cavitation sensor designed specifically for monitoring acoustic emissions generated by small microbubbles when driven by an applied acoustic field. Its novel features include a hollow, open-ended, cylindrical shape, with the sensor being a right circular cylinder of height 32 mm and external diameter 38 mm. The internal diameter of the sensor is 30 mm; its inner surface is fabricated from a 110-microm layer of piezoelectrically active film whose measurement bandwidth is sufficient to enable acoustic emissions up to and beyond 10 MHz to be monitored. When in use, the sensor is immersed within the liquid test medium and high frequency (megahertz) acoustic emissions occurring within the hollow body of the sensor are monitored. In order to shield the sensor response from events occurring outside the cylinder, the outer surface of the sensor cylinder is encapsulated within a special 4-mm thick polyurethane-based cavitation shield with acoustic properties specifically developed to be minimally perturbing to the 40 kHz applied acoustic field but attenuating to ultrasound generated at megahertz frequencies (plane-wave transmission loss > 30 dB at 1 MHz). This paper introduces the rationale behind the new sensor, describing details of its construction and the materials formulation program undertaken to develop the cavitation shield.

Journal Article↗

Solution structure of Escherichia coli Par10: The prototypic member of the Parvulin family of peptidyl-prolyl cis/trans isomerases.

E. coli Par10 is a peptidyl-prolyl cis/trans isomerase (PPIase) from Escherichia coli catalyzing the isomerization of Xaa-Pro bonds in oligopeptides with a broad substrate specificity. The structure of E. coli Par10 has been determined by multidimensional solution-state NMR spectroscopy based on 1207 conformational constraints (1067 NOE-derived distances, 42 vicinal coupling-constant restraints, 30 hydrogen-bond restraints, and 68 phi/psi restraints derived from the Chemical Shift Index). Simulated-annealing calculations with the program ARIA and subsequent refinement with XPLOR yielded a set of 18 convergent structures with an average backbone RMSD from mean atomic coordinates of 0.50 A within the well-defined secondary structure elements. E. coli Par10 is the smallest known PPIase so far, with a high catalytic efficiency comparable to that of FKBPs and cyclophilins. The secondary structure of E. coli Par10 consists of four helical regions and a four-stranded antiparallel beta-sheet. The N terminus forms a beta-strand, followed by a large stretch comprising three alpha-helices. A loop region containing a short beta-strand separates these helices from a fourth alpha-helix. The C terminus consists of two more beta-strands completing the four-stranded anti-parallel beta-sheet with strand order 2143. Interestingly, the third beta-strand includes a Gly-Pro cis peptide bond. The curved beta-strand forms a hydrophobic binding pocket together with alpha-helix 4, which also contains a number of highly conserved residues. The three-dimensional structure of Par10 closely resembles that of the human proteins hPin1 and hPar14 and the plant protein Pin1At, belonging to the same family of highly homologous proteins.

Amino Acid Sequence↗

Magnocellular dendrites: prototypic receiver/transmitters.

The hypothalamic magnocellular neurones of the supraoptic and paraventricular nuclei of mammals are among the best understood of all peptidergic neurones, and therefore serve as a model for understanding the functions of other peptidergic neurones. The release of vasopressin- and oxytocin-containing neurosecretory vesicles from their dendrites was first established 15 years ago. This local release is now known to have many functions, including controlling the interactions between oxytocin neurones and their surrounding glia, and facilitating and inhibiting the electrical activation of the neurones. Technical advances now permit dynamic analysis of dendritic release. Here, we review recent studies that focus on the conditional priming of dendritic peptide release by peptide-induced liberation of intracellular calcium, and the role of dendritic protein synthesis in the dendritic peptide release and the control of receptive properties of the neurones.

Animals↗

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