Functional modulation of human delta opioid receptor by neuropeptide FF

Background  

Neuropeptide FF (NPFF) plays a role in physiological pain sensation and opioid analgesia. For example, NPFF potentiates opiate-induced analgesia and the delta opioid receptor antagonist naltrindole inhibits NPFF-induced antinociception. The nature of the interactions between NPFF and opioid receptors seems to be complex and the molecular mechanisms behind the observed physiological effects are not known.     

Continuous two-dimensional field-flow fractionation: a novel technique for continuous separation and collection of macromolecules and particles

Instrumental techniques to analyse macromolecular and particulate materials have undergone rapid development in response to the need for high resolution, precise identification and characterization, and enrichment and collection for further analysis. Continuous two-dimensional field-flow fractionation (2D-FFF), which is described in this article, is a novel technique for separation and collection of macromolecules and particles. 2D-FFF is based on the conventional field-flow fractionation principle but with carrier flow in two-dimensions. This overview discusses the principle of the technique, describes the instrumentation and suggests potential applications and further extensions. An overview of the basic field-flow fractionation principle is presented.     

On the parametrization of self-similar and other fractal sets

We prove for many self-similar, and some more general, sets that if is the Hausdorff dimension of and is Hölder continuous with exponent , then the -dimensional Hausdorff measure of is .

     

Students’ Activity in Computer-Supported Collaborative Problem Solving in Mathematics

The purpose of this study was to analyse secondary school students’ (N = 16) computer-supported collaborative mathematical problem solving. The problem addressed in the study was: What kinds of metacognitive processes appear during computer-supported collaborative learning in mathematics? Another aim of the study was to consider the applicability of networked learning in mathematics. The network-based learning environment Knowledge Forum (KF) was used to support students’ collaborative problem solving. The data consist of 188 posted computer notes, portfolio material such as notebooks, and observations. The computer notes were analysed through three stages of qualitative content analysis. The three stages were content analysis of computer notesin mathematical problem solving, content analysis of mathematical problem solving activity and content analysis of the students’ metacognitive activity. The results of the content analysis illustrate how networked discussions mediated mathematical knowledge and students’ questions, while the mathematical problem solving activity shows that the students co-regulate their thinking. The results of the content analysis of the students’ metacognitive activity revealed that the students use metacognitive knowledge and make metacognitive judgments and perform monitoring during networked discussions. In conclusion, the results of this study demonstrate that working with the networked technology contributes to the students’ use of their mathematical knowledge and stimulates them into making their thinking visible. The findings also show some metacognitive activity in the students’ computer-supported collaborative problem solving in mathematics.     

On structuring problems of job design met in the development and maintenance of information systems

In the development and maintenance of information systems data processing tasks are assigned either to a computer or to a man. In this paper we consider five decisions made during the development phase. These decisions have an influence on the contents of jobs: 1. distribution of work between man and computer, 2. construction of man-computer interface, 3. grouping tasks into jobs, 4. design of control part of new information system, 5. assignment of people to jobs.During the use of an information system both the person and his job will change. Here various combinations of changes in a person-job pair are classified and analyzed.This research has been supported by the Academy of Finland.     

Determination of the conformation of 1,4-diheterocyclanes. I—The 1H n.m.r. spectrum and ring conformation of 3-methyl-2-oxo-1,4-dioxepane

The ¹H n.m.r. spectrum of 3-methyl-2-oxo-1,4-dioxepane was recorded at 300 and 60 MHz. The ring conformation was considered in terms of the spectral parameters and shown to be a twisted boat where the lactone grouping is approximately planar.     

Motion of a spin probe in hexagonal and lamellar potassium palmitate

Summary Nitroxyl radical Tempol dissolved in the hexagonal liquid-crystalline phase of potassium palmitate experienced a homogeneous time averaged environment. In the lamellar phase the radicals were distributed in two environments of different solvent polarities, which was demonstrated by simulation of the spectra.In both phases the nitroxyl probes were able to tumble comparatively freely (the rotational correlation time a was 0.15–0.9 ns).

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Zusammenfassung Das Nitroxylradikal Tempol wurde zur Untersuchung der Molekülbeweglichkeit in den verschiedenen Phasen im System Kaliumpalmitat — H₂O benutzt. Die hexagonale, flüssig-kristalline Phase erscheint homogen; in der lamellaren Phase wurden zwei verschiedene Umgebungen mit unterschiedlicher Lösungsmittelpolarität festgestellt. In beiden Phasen waren die Nitroxylradikale relativ frei beweglich ( = 0,15–9,9 nsec).

     

1H NMR spectra and stereochemistry of cis- and trans-5,6-dimethyl-2-oxo-1,4-dioxans

The ¹H NMR spectra of isomeric 5,6-dimethyl-2-oxo-1,4-dioxans have been recorded and the pertinent chemical shifts and coupling constants determined. The parameters indicate that both isomers exist as an equilibrium mixture of interconverting half chair ring conformations.     

On the stereochemistry of 1,4-diheterocyclanes. IV—carbon-13 NMR spectra and structural properties of 1,4-dioxane-2,3-diols and their methyl-substituted derivatives

The 1,4-dioxane-2,3-diols and a number of their methyl-substituted derivatives were synthesized and their ¹³C NMR spectra measured. The configurational properties were studied on the basis of the spectral data and chemical equilibration. For the parent compound the trans configuration is slightly more stable. The hydroxyl groups are predominantly axial. Introduction of a methyl group at the 2 position causes the cis configuration of the hydroxyl substituents to become more stable. The substituent effects on the chemical shifts were calculated and used to test the conformational homogeneity of the compounds. The results indicate a biased (chair) conformation for all the methyl-substituted derivatives which were studied. Methyl groups have strongly predominating equatorial orientation in each case studied.     

Compact middle-wave infrared Fabry-Perot interferometer with double metallic subwavelength gratings

We demonstrate a compact middle-wave IR (MWIR) Fabry-Perot (FP) interferometer by replacing the traditional distributed Bragg reflectors consisting of thick multilayer films with two identical metallic subwavelength gratings. The transmission efficiency, resonance peak position, and finesse of the FP interferometer can be controlled by tuning the structural parameters. The performance of the MWIR FP interferometer is verified by experiment, which shows its potential application as, for example, narrowband MWIR filter for gas detection.