| 561. |
- Sommar, Jonas, 1969, et al.
(författare)
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Distribution equilibrium of mercury (II) chloride between water and air applied to flue gas cleaning
- 2000
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Ingår i: Journal of Air and Waste Management Association. - 1096-2247. ; 50:9, s. 1663-1666
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Tidskriftsartikel (refereegranskat)abstract
- In the literature, different values of the distribution coef-ficient K H for HgCl 2 between water and air are present in a range that spans more than 3 orders of magnitude. In order to determine if a waste incineration scrubber solu-tion could become saturated with regard to HgCl 2 , an ac-curate experimental determination of the distribution constant of HgCl 2 at elevated temperatures is needed. In this work, the coefficient has been determined at four dif-ferent temperatures between 10 and 50 °C. The Arrhenius expression obtained is 5.5 x 10 5 x exp[-(8060 ± 2200)/T] with a corresponding enthalpy for the process HgCl 2 (aq)?I HgCl 2 (g) of 67 ± 20 kJ/mole. K H at 293 K was found to be ~5 x 10 -7 atm M -1 , which is in almost perfect agreement with an earlier study. Applying the obtained K H values to waste incineration scrubber conditions shows that no major saturation effect will occur.
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| 562. |
- Sott, Kristin, 1974, et al.
(författare)
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Adsorption behavior and enzymatically or chemically induced cross-linking of a mussel adhesive protein
- 2000
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Ingår i: Biofouling. - : Informa UK Limited. - 0892-7014 .- 1029-2454. ; 16:2-4, s. 119-132
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Tidskriftsartikel (refereegranskat)abstract
- The adsorption behavior of the mussel adhesive protein Mytilus edulis foot protein-1 (Mefp-1) has been investigated on a negatively charged polar SiO2 surface and an electrically inert non-polar CH3-terminated thiolated gold surface. How the structure of adsorbed Mefp-1 is changed upon chemically and enzymatically induced cross-linking using sodium periodate (NaIO4) and catechol oxidase, both of which transform DOPA residues in Mefp-1 into highly reactive o-quinones, was also investigated. The results are compared with those resulting from addition of Cu2+ to adsorbed Mefp-1, which forms complexes with and catalyses oxidation of DOPA residues, previously suggested to participate in the cohesive and adhesive properties of the byssus thread of M. edulis. By combining surface plasmon resonance (SPR) and quartz crystal microbalance/dissipation (QCM-D) measurements, the effects of these agents were investigated with respect to changes in the amount of coupled water, the viscoelastic properties (rigidity) and the hydrodynamic thickness of the protein adlayers. The layer of Mefp-1 formed on the bare CH3-terminated surface was elongated, flexible and coupled hydrodynamically a substantial amount of water, whereas Mefp-1 formed a rigidly attached adlayer on the SiO2 surface. Upon enzymatically and chemically induced cross-linking of Mefp-1 formed on the CH3 surface, the rigidity of the adlayer(s) increased significantly. A similar increase in the rigidity was observed also upon addition of Cu2+, suggesting that the high level of metal ions present in the byssus thread might be essential for the cohesive and adhesive properties of this protein. For the mass-uptake kinetics of enzymatically induced cross-linking, three different phases were observed and are interpreted as competition between binding of protein and release of coupled water. For the reaction with NaIO4 and Cu2+ only release of water affected the coupled mass. The importance of this type of information for an improved understanding of the strong adhesion and cohesive properties in marine environments is discussed.
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| 563. |
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| 564. |
- Speerstra, Joel, 1965, et al.
(författare)
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Documenting a clavichord by Lindholm and Söderström, and a brief history of Swedish measurements
- 2000
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Ingår i: Brauchli, B., Brauchli, S. & Galazzo, A. (eds). De clavicordio IV : proceedings of the 4th International Clavichord Symposium : atti del IV congresso internazionale sul clavicordo : Magnano, 8-11 September, 1999. - 889002691X ; , s. 161-176
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Konferensbidrag (refereegranskat)
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| 565. |
- Spåhr, H, et al.
(författare)
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Purification and characterization of RNA polymerase II holoenzyme from Schizosaccharomyces pombe.
- 2000
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Ingår i: The Journal of biological chemistry. - : Elsevier BV. - 0021-9258. ; 275:2, s. 1351-6
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Tidskriftsartikel (refereegranskat)abstract
- We have purified the RNA polymerase II holoenzyme from Schizosaccharomyces pombe to near homogeneity. The Mediator complex is considerably smaller than its counterpart in Saccharomyces cerevisiae, containing only nine polypeptides larger than 19 kDa. Five of these Mediator subunits have been identified as the S. pombe homologs to Rgr1, Srb4, Med7, and Nut2 found in S. cerevisiae and the gene product of a previously uncharacterized open reading frame, PMC2, with no clear homologies to any described protein. The presence of Mediator in a S. pombe RNA polymerase II holoenzyme stimulated phosphorylation of the C-terminal domain by TFIIH purified from S. pombe. This stimulation was species-specific, because S. pombe Mediator could not stimulate TFIIH purified from S. cerevisiae. We suggest that the overall structure and mechanism of the Mediator is evolutionary conserved. The subunit composition, however, has evolved to respond properly to physiological signals.
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| 566. |
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| 567. |
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| 568. |
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| 569. |
- Stener-Victorin, Elisabet, 1964, et al.
(författare)
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Effects of electro-acupuncture on anovulation in women with polycystic ovary syndrome.
- 2000
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Ingår i: Acta obstetricia et gynecologica Scandinavica. - : Wiley. - 0001-6349. ; 79:3, s. 180-8
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The present study was designed to evaluate if electro-acupuncture (EA) could affect oligo-/anovulation and related endocrine and neuroendocrine parameters in women with polycystic ovary syndrome (PCOS). METHODS: Twenty-four women (between the ages of 24 and 40 years) with PCOS and oligo-/amenorrhea were included in this non-randomized, longitudinal, prospective study. The study period was defined as the period extending from 3 months before the first EA treatment, to 3 months after the last EA treatment (10-14 treatments), in total 8-9 months. The menstrual and ovulation patterns were confirmed by recording of vaginal bleedings and by daily registrations of the basal body temperature (BBT). Blood samples were collected within a week before the first EA, within a week after the last EA and 3 months after EA. RESULTS: Nine women (38%) experienced a good effect. They displayed a mean of 0.66 ovulations/woman and month in the period during and after the EA period compared to a mean of 0.15 before the EA period (p=0.004). Before EA, women with a good effect had a significantly lower body-mass index (BMI) (p<0.001), waist-to-hip circumference ratio (WHR) (p=0.0058), serum testosterone concentration (p=0.0098), serum testosterone/sex hormone binding globulin (SHBG) ratio (p=0.011) and serum basal insulin concentration (p=0.0054), and a significantly higher concentration of serum SHBG (p=0.040) than did those women with no effect. CONCLUSION: Repeated EA treatments induce regular ovulations in more than one third of the women with PCOS. The group of women with good effect had a less androgenic hormonal profile before treatment and a less pronounced metabolic disturbance compared with the group with no effect. For this selected group EA offers an alternative to pharmacological ovulation induction.
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| 570. |
- Stener-Victorin, Elisabet, 1964, et al.
(författare)
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Effects of electro-acupuncture on nerve growth factor and ovarian morphology in rats with experimentally induced polycystic ovaries.
- 2000
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Ingår i: Biology of reproduction. - : Oxford University Press (OUP). - 0006-3363 .- 1529-7268. ; 63:5, s. 1497-503
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Tidskriftsartikel (refereegranskat)abstract
- Despite extensive research on the pathogenesis of polycystic ovary syndrome (PCOS), there is still disagreement on the underlying mechanisms. The rat model for experimentally induced polycystic ovaries (PCO)-produced by a single injection of estradiol valerate-has similarities with human PCOS, and both are associated with hyperactivity in the sympathetic nervous system. Nerve growth factor (NGF) is known to serve as a neurotrophin for both the sympathetic and the sensory nervous systems and to enhance the activity of catecholaminergic and possibly other neuron types. Electro-acupuncture (EA) is known to reduce hyperactivity in the sympathetic nervous system. For these reasons, the model was used in the present study to investigate the effects of EA (12 treatments, approximately 25 min each, over 30 days) by analyzing NGF in the central nervous system and the endocrine organs, including the ovaries. The main findings in the present study were first, that significantly higher concentrations of NGF were found in the ovaries and the adrenal glands in the rats in the PCO model than in the control rats that were only injected with the vehicle (oil or NaCl). Second, that repeated EA treatments in PCO rats resulted in concentrations of NGF in the ovaries that were significantly lower than those in non-EA-treated PCO rats but were within a normal range that did not differ from those in the untreated oil and NaCl control groups. The results in the present study provide support for the theory that EA inhibits hyperactivity in the sympathetic nervous system.
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