580 results match your criteria: "University of Joensuu[Affiliation]"
J Struct Biol
April 2008
Department of Chemistry, University of Joensuu, Yliopistonkatu 7, P.O. Box 111, FIN-80101 Joensuu, Finland.
We have solved a crystal structure from Melanocarpus albomyces laccase expressed in the filamentous fungus Trichoderma reesei (rMaL) at 1.3A resolution by using synchrotron radiation at 100K. At the moment, this is the highest resolution that has been attained for any multicopper oxidase.
View Article and Find Full Text PDFChem Commun (Camb)
October 2007
University of Joensuu, Department of Chemistry, P.O. Box 111, 80101 Joensuu, Finland.
H/D and guest-exchange ion-molecule reactions have been used as a new tool to elucidate the operation of multiple hydrogen bonding in gas-phase complexes formed between phosphonate cavitands and ethyl-substituted ammonium ions.
View Article and Find Full Text PDFInt J Nanomedicine
February 2008
Department of Physics and Mathematics, University of Joensuu, Joensuu, Finland.
The theory of optical properties of nanoparticles is considered with the aid of dispersion relations, which are based on the Kramers-Kronig analysis. It is shown that one can utilize rather general dispersion relations, which hold for liquid matrices that contain nanoparticles. Wiener bounds incorporating the Kramers-Kronig analysis are utilized in assessment of the complex permittivity of a nanoparticle.
View Article and Find Full Text PDFChem Commun (Camb)
January 2008
Department of Chemistry, University of Joensuu, Joensuu, Finland.
Quantum chemical calculations demonstrate the spherical aromaticity and high thermodynamic stability of Au(72), a predicted I-symmetric golden fullerene.
View Article and Find Full Text PDFRapid Commun Mass Spectrom
April 2008
Department of Chemistry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
Stereochemical differentiation of diasteromeric pairs of cis- and trans-2-aminocyclohexane-, -2-amino-4-cyclohexene-, and -2-aminocyclopentanecarboxylic acids was investigated with host-guest complexes where tetraethyl resorcarene was the host molecule. Diastereoselectivity was evaluated by ion/molecule reactions and collision-induced dissociation with electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS). The effect of varying the neutral reagent (n-propylamine, i-propylamine, diethylamine, and triethylamine) in ion/molecule reactions was evaluated.
View Article and Find Full Text PDFJ Mol Model
March 2008
Department of Chemistry, University of Joensuu, P.O. Box 111, FI-80101, Joensuu, Finland.
The applicability of several popular density functionals in predicting the geometrical parameters and energetics of transition metal carbonyl complexes of iron, ruthenium and osmium has been studied. The methods tested include pure GGA functionals (BLYP, BP86, OPBE, HCTH, PBE, VSXC) and hybrid GGA functionals (B3PW91, B3LYP, PBE1PBE, MPW1K, B97-2, B1B95, PBE1KCIS). The effect of changing the metal basis set from Huzinaga's all-electron basis to SDD scECP basis was also studied.
View Article and Find Full Text PDFActa Crystallogr Sect F Struct Biol Cryst Commun
January 2008
Department of Chemistry, University of Joensuu, PO Box 111, FIN-80101 Joensuu, Finland.
A D1 Fab fragment containing the allergen-binding variable domains of the IgE antibody was characterized by ESI FT-ICR mass spectrometry and crystallized with bovine beta-lactoglobulin (BLG) using the hanging-drop vapour-diffusion method at 293 K. X-ray data suitable for structure determination were collected to 2.8 A resolution using synchrotron radiation.
View Article and Find Full Text PDFAquat Toxicol
January 2008
Laboratory of Aquatic Ecology and Ecotoxicology, Faculty of Biosciences, University of Joensuu, Finland.
Humic substances may influence the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in aquatic environment. Relatively little is known how humic substances affect the biotransformation of PAHs in aquatic animals. Here we report how two different types of humic substances affected the accumulation of pyrene, a four-ringed PAH, to yolk-sac fry of landlocked salmon (Salmo salar m.
View Article and Find Full Text PDFChronobiol Int
April 2008
Faculty of Biosciences, University of Joensuu, Joensuu, Finland.
The raccoon dog (Nyctereutes procyonoides) is the only canid with passive overwintering in areas with cold winters, but the depth and rhythmicity of wintertime hypothermia in the wild raccoon dog are unknown. To study the seasonal rhythms of body temperature (T(b)), seven free-ranging animals were captured and implanted with intra-abdominal T(b) loggers and radio-tracked during years 2004-2006. The average size of the home ranges was 306+/-26 ha, and the average 24 h T(b) was 38.
View Article and Find Full Text PDFOpt Lett
June 1999
Department of Physics, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
We have observed the nonstationary polarization modulation of a speckle pattern transmitted through a photorefractive crystal under the alternating electric field of a square-wave form. A simple model based on Gaussian-beam propagation in the crystal with the diffusion type of nonlinearity is proposed to explain the main features of the experiment. Application of the phenomenon to noncontact and highly sensitive measurements of a rough surface movement is suggested.
View Article and Find Full Text PDFEcotoxicol Environ Saf
July 2008
Faculty of Biosciences, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
Joint effects of temperature and oxygen concentrations for the results of sediment toxicity tests were studied at 10 and 20 degrees C with 40% and 80% dissolved oxygen (DO) saturation. Growth, feeding rate, and reproduction of Lumbriculus variegatus (Oligochaete) and growth, emergence, and survival of Chironomus riparius (Diptera) were tested in a polluted and in a reference sediment. Both the feeding of L.
View Article and Find Full Text PDFFood Chem Toxicol
February 2008
University of Joensuu, Faculty of Biosciences, P.O. Box 111, FI-80101 Joensuu, Finland. @fi
The yellow tricholoma (Tricholoma flavovirens or Tricholoma equestre) is a wild mushroom species that was previously considered edible and tasty. Recently, it caused several cases of delayed rhabdomyolysis in humans and elevated serum creatine kinase (CK) activities in laboratory mice (Mus musculus) in a dose-response study. The present study continued to examine the effects of prolonged T.
View Article and Find Full Text PDFChemosphere
March 2008
University of Joensuu, Faculty of Biosciences, P.O. Box 111, FI-80101 Joensuu, Finland.
beta-Sitosterol is a weakly estrogenic phytosterol used extensively in functional foods to lower elevated serum cholesterol concentrations due to its inhibitory action on intestinal cholesterol absorption. It caused previously decreased sex steroid concentrations in fish and lowered sperm counts in rats. In the American mink (Neovison vison), litter size increased slightly due to dietary beta-sitosterol supplement.
View Article and Find Full Text PDFPhilos Trans R Soc Lond B Biol Sci
July 2008
Faculty of Forestry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
This study investigated the sensitivity of managed boreal forests to climate change, with consequent needs to adapt the management to climate change. Model simulations representing the Finnish territory between 60 and 70 degrees N showed that climate change may substantially change the dynamics of managed boreal forests in northern Europe. This is especially probable at the northern and southern edges of this forest zone.
View Article and Find Full Text PDFEnviron Toxicol Chem
December 2007
University of Joensuu, Faculty of Biosciences, Finland.
In some kinetic studies with aquatic invertebrates, the bioaccumulation of polyaromatic hydrocarbons (PAHs) has been observed to peak at the beginning of the test. This has been explained by the depletion of PAHs from pore water due to limited desorption during the bioaccumulation test or, alternatively, by the activation of biotransformation mechanisms in the organisms. In the present study, we exposed the aquatic oligochaetes, Lumbriculus variegatus, to creosote oil-contaminated sediments to examine the bioaccumulation of PAHs and to clarify the importance of contaminant depletion and biotransformation for it.
View Article and Find Full Text PDFStructure
November 2007
Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
Allergies are caused by the immune reaction to commonly harmless proteins, allergens. This reaction is typified by immunoglobulin E (IgE) antibodies. We report the crystal structure of an IgE Fab fragment in complex with beta-lactoglobulin (BLG), one of the major allergens of bovine milk.
View Article and Find Full Text PDFInt J Biol Macromol
January 2008
University of Joensuu, Department of Chemistry, PO Box 111, FI-80101 Joensuu, Finland.
Kinetic as well as energetic aspects of the thermal denaturation of Trichoderma reesei endo-1,4-beta-xylanase II (TRX II) and its three thermostable disulfide mutants were characterized by means of differential scanning calorimetry (DSC) in different solution conditions. The calorimetric transitions were strongly scan-rate dependent, characteristic for an irreversible, kinetically controlled protein denaturation. The DSC-determined T*-values (the temperature at which the denaturation rate constant equals 1min(-1)), and the activation free energies for the transitions are consistent with the apparent transition temperatures of TRX II determined earlier by mass spectrometry.
View Article and Find Full Text PDFProtein Eng Des Sel
November 2007
Department of Chemistry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
Twelve members of the family 11 xylanases, including both mesophilic and thermophilic proteins, were studied using molecular dynamics (MD). Simulations of xylanases were carried out in an explicit water environment at four different temperatures, 300, 400, 500 and 600 K. A difference in thermotolerance between mesophilic and thermophilic xylanases became clear: thermophilic xylanases endured heat in higher simulation temperatures better than mesophilic ones.
View Article and Find Full Text PDFBMC Biol
November 2007
Faculty of Biosciences, University of Joensuu, FI-80101 Joensuu, Finland.
Background: Plants, plant-feeding insects, and insect parasitoids form some of the most complex and species-rich food webs. According to the classic escape-and-radiate (EAR) hypothesis, these hyperdiverse communities result from coevolutionary arms races consisting of successive cycles of enemy escape, radiation, and colonization by new enemy lineages. It has also been suggested that "enemy-free space" provided by novel host plants could promote host shifts by herbivores, and that parasitoids could similarly drive diversification of gall form in insects that induce galls on plants.
View Article and Find Full Text PDFJ Mass Spectrom
April 2008
University of Joensuu, Department of Chemistry, P.O. Box 111, FI-80101 Joensuu, Finland.
The oxidation reaction of a laccase mediator ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) was studied by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS). Oxidation products of ABTS were measured after reaction times that varied from a few minutes up to several days and both positive and negative ionization modes were employed. Exact mass measurements and collision-induced dissociation (CID) experiments were used to characterize the structures of the ions formed.
View Article and Find Full Text PDFDev Neuropsychol
January 2008
Department of Psychology, University of Joensuu, Joensuu, Finland.
The working memory functions and processing speed of 35 adolescents born preterm (< or = 32 weeks of gestation) and those of 31 control adolescents were assessed at the age of 16 years. All study participants were free from major disabilities. There were no statistically significant differences in verbal IQ between the study groups.
View Article and Find Full Text PDFActa Physiol (Oxf)
November 2007
Faculty of Biosciences, University of Joensuu, Joensuu, Finland.
Aim: Sodium current (I(Na)) of the mammalian heart is resistant to tetrodotoxin (TTX) due to low TTX affinity of the cardiac sodium channel (Na(v)) isoform Na(v)1.5. To test applicability of this finding to other vertebrates, TTX sensitivity of the fish cardiac I(Na) and its molecular identity were examined.
View Article and Find Full Text PDFEur J Paediatr Neurol
May 2008
Department of Psychology, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
In this longitudinal study the development of preterm and control children was followed from infancy until adolescence. School performance at the age of 16 in subjects born very preterm with a gestational age (GA) of
J Comp Physiol B
February 2008
Faculty of Biosciences, University of Joensuu, Joensuu, Finland.
Arvicolinae voles are small herbivores relying on constant food availability with weak adaptations to tolerate prolonged food deprivation. The present study performed a comparative analysis on the responses to 4-18 h of food deprivation in the common vole (Microtus arvalis) and the tundra vole (Microtus oeconomus). Both species exhibited rapid decreases in the plasma and liver carbohydrate concentrations during phase I of fasting and the decline in the liver glycogen level was more pronounced in the tundra vole.
View Article and Find Full Text PDFChemphyschem
November 2007
Department of Chemistry, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland.
We predict the existence of two novel families of arsenic nanostructures: icosahedral cages and ring-shaped chains. Quantum chemical calculations on the cages, rings, and the experimentally known allotropes of arsenic suggest the nanostructures to be thermodynamically stable. The icosahedral cages are modifications of the gray allotrope of arsenic, while the ring-shaped chains are structurally related to the red allotrope of phosphorus.
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