580 results match your criteria: "University of Joensuu[Affiliation]"
J Exp Zool A Comp Exp Biol
October 2005
Department of Biology, University of Joensuu, Joensuu, Finland.
The raccoon dog (Nyctereutes procyonoides) is an omnivorous canid with autumnal hyperphagia and fattening followed by mid-winter passivity and fasting in boreal latitudes with seasonal snow cover. The effects of two different feeding levels (400 or 200 kcal/animal/d) or fasting (5-week fasting+1-week feeding+3-week fasting) on plasma lipids, sex steroids and reproductive success of farm-bred raccoon dogs (n=60 females and 24 males) were studied in winter. The body masses, body mass indices (BMIs) and levels of plasma triacylglycerols (TG), total cholesterol and low- and high-density lipoprotein cholesterol did not differ between the fed and the restrictively fed animals.
View Article and Find Full Text PDFEnviron Pollut
March 2006
University of Joensuu, Department of Biology, Yliopistokatu 7, FIN-80100 Joensuu, Finland.
The success of the rapidly desorbing fraction as an available fraction was challenged by using sediment ingesting and non-ingesting oligochaetes (Lumbriculus variegatus) together with passive samplers (semipermeable membrane devices, SPMDs) in accumulation and kinetic modelling exercises for carbon-14 labelled model compounds (pyrene, benzo[a]pyrene and 3,4,3',4'-tetrachlorobiphenyl). Passive samplers clearly produced lower uptake rate constants and steady state factors than either of the oligochaete treatments when residue concentrations were based on animal lipid or total SPMD weight. The rapidly desorbing chemical fractions in sediments did not show a significant relationship with the biota sediment accumulation factors or SPMD accumulation factors.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
August 2005
Department of Physics, University of Joensuu, P.O. Box 111, FI-80101 Joensuu, Finland.
A coherent-mode representation for spatially and spectrally partially coherent pulses is derived both in the space-frequency domain and in the space-time domain. It is shown that both the cross-spectral density and the mutual coherence function of partially coherent pulses can be expressed as a sum of spatially and spectrally and temporally completely coherent modes. The concept of the effective degree of coherence for nonstationary fields is introduced.
View Article and Find Full Text PDFJ Exp Zool A Comp Exp Biol
September 2005
Department of Biology, University of Joensuu, FIN-80101 Joensuu, Finland.
The raccoon dog (Nyctereutes procyonoides) is a nocturnal canid thought to utilise passive wintering strategy in the boreal climate. To record the deep body temperature (T(b)), 12 farmed raccoon dogs were implanted with intra-abdominal T(b) loggers on November 26, 2003. Between December 3, 2003 and January 27, 2004 half of the animals were fasted for 8 weeks.
View Article and Find Full Text PDFChemosphere
September 2005
Laboratory of Aquatic Ecology and Ecotoxicology, Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
Pore water was separated either with or without water extraction prior to centrifugation (7600 or 20,000 x g) in order to investigate the effects of separation procedure on the amount and properties of dissolved organic matter (DOM i.e. the material passing through a 0.
View Article and Find Full Text PDFSoz Praventivmed
December 2005
Savonlinna Department of Education, University of Joensuu, Finland.
Objective: To study consumption of special diet (disease-related and non disease-related) among Finnish adolescents during 1979-2001.
Methods: Self-administered questionnaires were mailed to nationally representative samples of 12- (except in 1979), 14-, 16-, and 18-year-olds in 1979, 1993, 1997, 1999 and 2001.
Results: The total number of respondents was 33998.
Environ Pollut
October 2005
Natural Product Research Laboratory, Department of Biology, University of Joensuu, PO Box 111, FIN-80101 Joensuu, Finland.
Reflection by waxy or resinous surface structures and hairs, repair reactions of biomolecules and induction of different sheltering components provide the means of plant protection from harmful solar UV-B radiation. Secondary products, especially flavonoids and phenolic acids as defense components are also important in plant tolerance to UV-B, fulfilling the dual role as screens that reduce UV-B penetration in plant tissues, and as antioxidants protecting from damage by reactive oxidant species. Plants are sensitive to UV-B radiation, and this sensitivity can be even more clone-specific than species-specific.
View Article and Find Full Text PDFJ Med Chem
June 2005
Department of Chemistry, University of Joensuu, Joensuu, Finland.
Novel 1-R-imidazole-2-nitrolic acids and 1-R-imidazole-5-nitrolic acids (R: H, Me, Bn) were synthesized from oximes by treatment with a mixture of fuming nitric acid and acetic acid. The effects of these potential nitric oxide-donating compounds were tested on ocular variables such as intraocular pressure and formation of cyclic guanosine-3,5'-monophosphate in the incubation of porcine iris-ciliary body.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
October 2005
University of Joensuu, Department of Biology, P.O. Box 111, 80101 Joensuu, Finland.
Cold-acclimated (CA) phenotype of trout heart was induced by 4-wk acclimation at 4 degrees C and was characterized by 32.7% increase in relative heart mass and 49.8% increase in ventricular myocyte size compared with warm-acclimated (WA; 18 degrees C) fish (P < 0.
View Article and Find Full Text PDFJ Comp Physiol B
July 2005
Department of Biology, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland.
The aim of this study was to investigate the adaptations of protein metabolism to seasonal fasting in an actively wintering boreal carnivore. Fifty farm-bred male American minks Mustela vison were divided into a fed control group and four experimental groups fasted for 2, 3, 5 or 7 days. The responses of nitrogen metabolism to wintertime food deprivation were determined by measuring the rate of weight loss, the tissue total protein concentrations and the plasma amino acid, urea, ammonia, uric acid and total protein levels.
View Article and Find Full Text PDFArch Environ Contam Toxicol
April 2005
Department of Biology, Laboratory of Aquatic Ecology and Ecotoxicology, University of Joensuu, 111, FIN-80101, Joensuu, Finland.
The study concerns the toxicity of a phytosterol mixture, ultrasitosterol, consisting mainly of beta-sitosterol 75.7% and beta-sitostanol 13.0%, to grayling (Thymallus thymallus) embryos.
View Article and Find Full Text PDFNoncovalent binding of thioxylo-oligosaccharide inhibitors, methyl 4-thio-alpha-xylobioside (S-Xyl2-Me), methyl 4,4II-dithio-alpha-xylotrioside (S-Xyl3-Me), methyl 4,4II,4III-trithio-alpha-xylotetroside (S-Xyl4-Me), and methyl 4,4II,4III,4IV-tetrathio-alpha-xylopentoside (S-Xyl5-Me), to three family 11 endo-1,4-beta-xylanases from Trichoderma reesei (TRX I and TRX II) and Chaetomium thermophilum (CTX) was characterized using electrospray ionization Fourier transform ion cyclotron resonance (FT-ICR) MS and X-ray crystallography. Ultra-high mass-resolving power and mass accuracy inherent to FT-ICR allowed mass measurements for noncovalent complexes to within |DeltaM|average of 2 p.p.
View Article and Find Full Text PDFEnviron Toxicol Chem
April 2005
Department of Biology, University of Joensuu, FIN-80101, Joensuu, Finland.
In bioavailability studies, the biota sediment accumulation factor (BSAF) is invoked to describe the thermodynamic partitioning of a hydrophobic organic contaminant (HOC) between the organism lipid and the organic carbon fraction of the sedimentary matrix and accounts for differences in bioavailability among sediments. Bioaccumulation experiments were performed with Lumbriculus variegatus and Diporeia species exposed in seven sediments dosed with 2,4,5,2',4',5'-hexachlorobiphenyl (HCBP) and benzo[a]pyrene (BaP) or pyrene (PY) and 3,4,3',4'-tetrachlorobiphenyl (TCBP). The BSAF values for the nonplanar HCBP were consistent with equilibrium partitioning theory (EQP) and averaged 2.
View Article and Find Full Text PDFInorg Chem
April 2005
Department of Chemistry, University of Joensuu, P.O. Box 111, FIN-80101 Joensuu, Finland.
Four new zinc and cadmium bisphosphonates [{NaZn(Cl2CP2O6H)(H2O)5}]n (1), [{Cd2(Cl2CP2O6)(H2O)4}.H2O]n (2), [{Zn(Cl2CP2O6Pri2)(H2O)3}.H2O]n (3), and [{Cd2(Cl2CP2O6Pri2)2(MeOH)2(H2O)2}.
View Article and Find Full Text PDFReprod Toxicol
July 2005
Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
Due to beneficial health effects phytosterols (PS) are increasingly added to functional foods. The aim of the present study was to investigate the chronic effects of a dietary PS mixture (5mg/kg/day), containing mainly beta-sitosterol, on the reproduction of the mouse. General reproductive parameters, postnatal development, growth and survival of pups, weight of sex organs, the concentrations of plasma sex steroids and testicular testosterone were monitored across five generations (F(0)-F(4)).
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
February 2005
Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
Adiponectin (Acrp30) and peptide YY (PYY) are weight-regulatory hormones participating in the control of energy homeostasis. This study investigated the effects of long-term wintertime fasting on plasma Acrp30 and PYY levels in the carnivorous blue fox, a farm-bred variant of the arctic fox (Alopex lagopus). Plasma Acrp30 and PYY concentrations were determined with radioimmunoassays during a 22-day period of fasting, which led to a 20.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
February 2005
Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
The aim of this study was to investigate whether the actively wintering American mink Mustela vison is strictly dependent on continuous food availability or if it has evolved physiological adaptations to tolerate nutritional scarcity. Fifty farm-bred male minks were divided into a fed control group and four experimental groups fasted for 2, 3, 5 or 7 days. The rate of weight loss was several-fold higher (1.
View Article and Find Full Text PDFProtein Eng Des Sel
December 2004
Laboratory of Bioprocess Engineering, Helsinki University of Technology, PO Box 6100, 02015-HUT and Department of Chemistry, University of Joensuu, PO Box 111, 80101 Joensuu, Finland.
Xylose isomerase (XI) catalyzes the isomerization and epimerization of hexoses, pentoses and tetroses. In order to clarify the reasons for the low reaction efficiency of a pentose sugar, L-arabinose, we determined the crystal structure of Streptomyces rubiginosus XI complexed with L-arabinose. The crystal structure revealed that, when compared with D-xylose and D-glucose, L-arabinose binds to the active site in a partially different position, in which the ligand has difficulties in binding the catalytic metal M2.
View Article and Find Full Text PDFPlant Cell Rep
May 2005
Department of Biology, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland.
The prevention of flower formation is important for avoiding the spread of transgenes from genetically modified plants into wild populations. Moreover, the resources not expended for the generation of flowers and fruits might be allocated to increased vegetative growth. We have been developing methods for preventing flower formation in silver birch (Betula pendula), a tree species of considerable economical importance in the boreal region.
View Article and Find Full Text PDFHeredity (Edinb)
April 2005
Department of Biology, University of Joensuu, PO Box 111, FIN-80101 Joensuu, Finland.
Wood lemming (Myopus schisticolor) populations are characterized by female biased sex ratios and cyclic variations in population size. Both of these characteristics are assumed to reduce genetic variation and thus affect the evolutionary adaptation of the species. We addressed these questions by studying the genetic structure of a wood lemming population from eastern Finland by isozyme markers during a 21-year period, which corresponds to 40-50 generations.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
January 2005
University of Joensuu, Department of Physics, FI-80101 Joensuu, Finland.
A theory of open laser resonators is formulated within the framework of the electromagnetic coherence theory. It is shown that if only one Fox-Li mode contributes to the field at a given frequency, then the field at that frequency is necessarily completely coherent in view of the space-frequency counterpart of the recently introduced degree of coherence of electromagnetic fields [Opt. Express 11, 1137 (2003)].
View Article and Find Full Text PDFPsychol Rep
December 2004
Department of Psychology, University of Joensuu, Finland.
The present study assessed the psychometric properties of a multidimensional measure of parents' assessments of their children's abilities, including problem-solving skills, social skills, dexterity, creativity, and learning motivation. A nationwide sample of Finnish parents (N=432), representing two educational groups, both mothers (64%) and fathers (36%) whose mean age was 37.8 yr.
View Article and Find Full Text PDFIEEE Trans Image Process
January 2005
University of Joensuu, FI-80101 Joensuu, Finland.
We propose a method for compressing color map images by context tree modeling and arithmetic coding. We consider multicomponent map images with semantic layer separation and images that are divided into binary layers by color separation. The key issue in the compression method is the utilization of interlayer correlations, and to solve the optimal ordering of the layers.
View Article and Find Full Text PDFToxicol Appl Pharmacol
January 2005
Department of Biology, University of Joensuu, PO Box 111, FIN-80101 Joensuu, Finland.
The aim of the present study was to examine the reproductive effects of two perorally applied phytoestrogens, genistein (8 mg/kg/day) and beta-sitosterol (50 mg/kg/day), on the mink (Mustela vison) at human dietary exposure levels. Parental generations were exposed over 9 months to these phytoestrogens and their offspring were exposed via gestation and lactation. Parents and their offspring were sampled 21 days after the birth of the kits.
View Article and Find Full Text PDFJ Exp Zool A Comp Exp Biol
January 2005
Department of Biology, University of Joensuu, P.O. Box 111, FIN-80101, Joensuu, Finland.
The aim of the study was to investigate the circannual rhythms of leptin and ghrelin in the blue fox, a variant of the endangered arctic fox, in relation to its seasonal cycles of body mass, adiposity and food intake. The effects of long-term fasting and exogenous melatonin treatment on these weight-regulatory hormones were also investigated. The leptin concentrations of the blue fox increased during the autumnal accumulation of fat and decreased during the wintertime and vernal weight loss periods.
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