580 results match your criteria: "University of Joensuu[Affiliation]"
Lipids
December 2007
Faculty of Biosciences, University of Joensuu, P.O. Box 111, 80101, Joensuu, Finland.
Previous studies on laboratory rodents, rabbits and humans have demonstrated that fatty acid (FA) mobilization from white adipose tissue (WAT) is selective and its efficiency is related to FA structure. Selective FA mobilization was also documented in a carnivore, the farmed raccoon dog (Nyctereutes procyonoides), fasted for 8 weeks. The present study explored whether similar selectivity of FA mobilization was manifested in wild mammals experiencing seasonal food scarcity and abundance.
View Article and Find Full Text PDFDalton Trans
August 2007
Department of Chemistry, University of Joensuu, Department of Chemistry, P. O. Box 111, FIN-80101, Joensuu, Finland.
A novel synthesis method is introduced for the preparation of [Os(NN)(CO)(2)X(2)] complexes (X = Cl, Br, I, and NN = 2,2'-bipyridine (bpy) or 4,4'-dimethyl-2,2'-bipyridine (dmbpy)). In the first step of this two-step synthesis, OsCl(3) is reduced in the presence of a sacrificial metal surface in an alcohol solution. The reduction reaction produces a mixture of trinuclear mixed metal complexes, which after the addition of bpy or dmbpy produce a trans(Cl)-[Os(NN)(CO)(2)Cl(2)] complex with a good 60-70% yield.
View Article and Find Full Text PDFArch Environ Contam Toxicol
November 2007
Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
The physiological responses of juvenile rainbow trout (Oncorhynchus mykiss) to lithium (as LiCl) in moderately hard freshwater (CaCO(3) = 120-140 ppm, Na(+) = approximately 0.6 mM) were studied. The study employed a 15-day step-up exposure regime; 66 microg/L Li for the first 9 days and 528 microg/L for the next 6 days.
View Article and Find Full Text PDFActa Crystallogr Sect F Struct Biol Cryst Commun
September 2007
Department of Chemistry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
Cellobiohydrolases are enzymes that cleave off cellobiose units from cellulose chains in a processive manner. Melanocarpus albomyces Cel7B is a thermostable single-module cellobiohydrolase that has relatively low activity on small soluble substrates at room temperature. It belongs to glycoside hydrolase family 7, which includes endo-beta-1,4-glucanases and cellobiohydrolases.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
September 2007
InFotonics Center, University of Joensuu, Finland.
For digital cameras, device-dependent pixel values describe the camera's response to the incoming spectrum of light. We convert device-dependent RGB values to device- and illuminant-independent reflectance spectra. Simple regularization methods with widely used polynomial modeling provide an efficient approach for this conversion.
View Article and Find Full Text PDFCortex
July 2007
Academy of Finland, University of Joensuu, Joensuu, Finland.
Most eighteenth-century philosophers tended to attach memory to imagination, thinking that memory basically consists in the reproduction of previously received sensations, which have perhaps only lost some of their vividness. In his Essai sur l'origine des connoissances humaines (1746) Condillac, however, insists on separating memory and imagination. This is surprising in so far as one would expect him, as a sensualist, to reduce memory to the faculty of reproducing sensations in the manner of Locke and other empiricists.
View Article and Find Full Text PDFAppl Opt
August 2007
Department of Physics and Mathematics, University of Joensuu, Finland.
We exploit efficient dispersion relations, which were developed for terahertz spectroscopy, to show their validity for testing linear and nonlinear optical spectra. As an example, we deal with the measured data for complex reflectivity of a KCl crystal and complex nonlinear susceptibility of a polysilane. It is suggested that the spectral data presented in the literature both for the KCl and the polysilane are consistent with the presented spectra analysis method.
View Article and Find Full Text PDFBehav Res Methods
May 2007
Department of Computer Science, University of Joensuu, Joensuu, Finland.
Investigation of cognitive processes and visual attention during problem-solving tasks is an important part of understanding human reasoning. Eyetracking technology has proven to have many benefits in revealing visual attention patterns. However, the high price of accurate eyetrackers and the difficulties associated with using them represent major obstacles to their wider application.
View Article and Find Full Text PDFEval Program Plann
February 2007
Department of Computer Science, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
This article presents the results of a case study in youth participatory program planning conducted in the context of a nonformal technology-education program in eastern Finland. The purpose of the program was to have youth, university, and business stakeholders work together to create the Learning Door, a door that would meet the needs of older people and people with disabilities. The participatory program planning process that was used involved clarifying the mission, roles, and modes of collaboration as well as creating stakeholder matrices, logic models, program plans, and implementation plans.
View Article and Find Full Text PDFJ Biol Chem
September 2007
Department of Chemistry, University of Joensuu, P. O. Box 111, 80101 Joensuu, Finland.
Hydrophobins are small, amphiphilic proteins secreted by filamentous fungi. Their functionality arises from a patch of hydrophobic residues on the protein surface. Spontaneous self-assembly of hydrophobins leads to the formation of an amphiphilic layer that remarkably reduces the surface tension of water.
View Article and Find Full Text PDFJ Comp Physiol B
October 2007
Faculty of Biosciences, University of Joensuu, P.O. Box 111, 80101, Joensuu, Finland.
The American marten (Martes americana) is a boreal forest marten with low body adiposity throughout the year. The aim of this study was to investigate the adaptations of this lean-bodied species to fasting for an ecologically relevant duration (48 h) by exposing eight farm-bred animals to total food deprivation with seven control animals. Selected morphological and hematological parameters, plasma and serum biochemistry, endocrinological variables and liver and white adipose tissue (WAT) enzyme activities were determined.
View Article and Find Full Text PDFAppl Opt
July 2007
Department of Physics and Mathematics, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
Subwavelength metallic and dielectric diffraction gratings which rotate the linear polarization of incident light by 90 degrees are examined. Using rigorous diffraction theory in total-internal-reflection configuration, it is shown that full conversion from incident transverse electric field to transverse magnetic zero-order field can be achieved with both dielectric and metallic elements, but dielectric gratings provide higher efficiency and are thus preferable. The fabrication aspects and constraints are discussed in detail and the behavior of the gratings over broad wavelength bands is presented.
View Article and Find Full Text PDFOecologia
September 2007
Department of Biology, University of Joensuu, Joensuu, Finland.
Long-term studies were carried out in central Finland between 1985 and 2003 to examine the temporal and spatial variation in the density of otter populations. Snow tracking was used to estimate the total population and the number of litters in the study area. In total 52 otters, including 16 cubs in 11 litters, lived in the study area (1,650 km(2)) in 2002-2003.
View Article and Find Full Text PDFLangmuir
July 2007
Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
Molecular dynamics simulations were used to study the wetting of nanogrooved PE and PVC polymer surfaces. The contact angles, equilibrium states, and equilibrium shapes of two nanosized water droplets were analyzed on surfaces with 1D-arranged periodic roughness of various dimensions. The composite solid-liquid contact, which is preferred in practical applications and in which a droplet rests on top of the surface asperities, was observed on the roughest PE surfaces, whereas water filled the similar but slightly deeper grooves on PVC surfaces.
View Article and Find Full Text PDFTree Physiol
September 2007
University of Joensuu, Faculty of Forestry, P.O. Box 111, FI-80101 Joensuu, Finland.
We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment.
View Article and Find Full Text PDFLipids
July 2007
Faculty of Biosciences, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland.
The mobilization of fatty acids (FA) is a selective process in humans, rodents and the few previously studied carnivores. The FA composition of and mobilization from different fat depots reflect the functions of adipose tissues, e.g.
View Article and Find Full Text PDFLangmuir
June 2007
Department of Chemistry, University of Joensuu, FI-80101 Joensuu, Finland.
Superhydrophobic polyolefin surfaces were prepared by simultaneous micro- and nanostructuring. Electropolished aluminum foil was microstructured with a micro working robot and then anodized in polyprotic acid. The surface microstructure can be tailored by adjusting the settings of the micro working robot and the nanostructure by adjusting the parameters of the anodization procedure.
View Article and Find Full Text PDFEcotoxicol Environ Saf
November 2007
Department of Biology, University of Joensuu, P.O. Box 111, FI-80101 Joensuu, Finland.
The objective of this study is to discern the effects of increased waterborne lithium and potassium on rainbow trout gill histology, lipid composition, and enzyme activity. The study aims to elucidate the effects of these ions in the laboratory in concentrations similar to those prevailing in a forest lake Poppalijärvi in a contaminated mining area in NW Russia. Under the lithium and potassium exposure, the fish were further stressed by high pH (8.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
June 2007
Department of Physics and Mathematics, University of Joensuu, Finland.
We present a study on subwavelength-structured surfaces with optimized color properties and antireflection properties in the range of the visible spectrum. Problematic blueness of the nanostructured surface has been eliminated under viewing angles from 0 to 35 deg by designing and optimizing the antireflective surface parameters. The rigorous diffraction theory is used to minimize the surface reflection by simultaneously keeping the chromaticity coordinates of the reflected light in the white domain.
View Article and Find Full Text PDFAnal Biochem
June 2007
Department of Chemistry, University of Joensuu, FI-80101 Joensuu, Finland.
A direct mass spectrometric approach was used for the determination of steady-state kinetic parameters, the turnover number (k(cat)), the Michaelis constant (K(M)), and the specificity constant (k(cat)/K(M)) for an enzyme-catalyzed hydrolysis of xylooligosaccharides. Electrospray ionization mass spectrometry was performed to observe product distributions and to determine k(cat), K(M), and k(cat)/K(M) values for Trichoderma reesei endo-1,4-beta-xylanase II (TRX II) with xylohexaose (Xyl(6)), xylopentaose (Xyl(5)), xylotetraose (Xyl(4)), and xylotriose (Xyl(3)) as substrates. The determined k(cat)/K(M) values (0.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
June 2007
Department of Chemistry, University of Joensuu, 80101 Joensuu, Finland.
Host-guest complexes where tetraethyl resorcarene was the host molecule were used to study the stereoselectivity of diasteromeric pairs of di-endo- and di-exo-2,3-disubstituted norbornane and norbornene amino acids by ion-molecule reactions and collision-induced dissociation with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Both methods showed stereoselectivity for the diastereomeric pairs. Particularly high selectivity was achieved for di-endo- and di-exo-2,3-disubstituted norbornane amino acids with ion-molecule reactions.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
August 2007
Faculty of Biosciences, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
Fatty acid (FA) composition in the intraabdominal (IAB), subcutaneous (SC) and peripheral adipose tissues of the semiaquatic American mink (Mustela vison) was examined in comparison to the diet by gas-liquid chromatography. There was a clear compositional gradient from the IAB via SC to peripheral adipose tissues and the anatomically different adipose tissues accumulated or metabolized FA selectively. The total lipids of the body appendages had smaller proportions of saturated (SFA) and larger proportions of monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) than the lipids of the trunk adipose tissues.
View Article and Find Full Text PDFJ Phys Chem B
April 2007
Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
Molecular dynamics simulations were used to study the effect of periodic roughness of PE and PVC polymer surfaces on the hydrophobicity. Pillars of different lateral dimensions and heights were derived from flat crystalline surfaces, and the results of nanoscale simulations on the structured surfaces were compared with theoretical predictions of the Wenzel and Cassie equations. Hydrophobicity increased on all rough surfaces, but the increase was greater on the structured PE surfaces because of the larger water contact angle on the flat PE surface than the corresponding PVC surface.
View Article and Find Full Text PDFChemistry
September 2007
Department of Chemistry, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland.
The existence of two new allotropic forms of phosphorus, icosahedral cages and ring-shaped chains, is predicted. The cages and rings are nanostructural modifications of the black and the red phosphorus, respectively. The icosahedral and ring-shaped allotropes are compared with the experimentally known allotropic forms of phosphorus by quantum chemical methods.
View Article and Find Full Text PDFInorg Chem
April 2007
Department of Chemistry, University of Joensuu, P.O. Box 111, FI-80101 Joensuu, Finland. pipsa.hirva@ joensuu.fi
Properties of dirhodium catalysts with cyclometalated aryl phosphine ligands have been studied. We report here the study of the acid-base reaction of Rh2(RCO2)2(PC)2(H2O)2 catalysts (PC = cyclometalated aryl phosphine) with different Lewis bases. The determination of the equilibrium constants of these reactions can be used to study to which extent the properties of the axial coordination site of the catalyst, considered the active site, are affected by modification of the metalated phosphines, the carboxylate ligands, or the incoming axial ligand.
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