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21.
Vivi Flou Hjorth Jensen Anne-Marie M?lck Annette Heydenreich Karin Juul Jensen Line Olrik Bertelsen Lene Alifrangis Lene Andersen Henrik S?eborg Melissa Chapman Jens Lykkesfeldt Ingrid Brück B?gh 《Journal of toxicologic pathology》2016,29(1):17-30
New insulin analogues with a longer duration of action and a flatter pharmacodynamic profile are developed to improve convenience and safety for diabetic patients. During the nonclinical development of such analogues, safety studies must be conducted in nondiabetic rats, which consequently are rendered chronically hypoglycemic. A rat comparator model using human insulin would be valuable, as it would enable differentiation between effects related to either persistent insulin-induced hypoglycemia (IIH) or a new analogue per se. Such a model could alleviate the need for an in-study-comparator and thereby reduce the number of animals used during development. Thus, the aims of the present study were i) to develop a preclinical animal model of persistent hypoglycemia in rats using human insulin infusion for four weeks and ii) to investigate histopathological changes in sciatic nerves and quadriceps femoris muscle tissue, as little is known about the response to persistent hypoglycemia in these tissues. Histopathologic changes in insulin-infused animals included axonal degeneration and myofibre degeneration. To our knowledge, this is the first study to show that persistent IIH provokes peripheral nerve and skeletal myofiber degeneration within the same animals. This suggests that the model can serve as a nonclinical comparator model during development of long-acting insulin analogues. 相似文献
22.
Lena Rimsten Tove Stenberg Roger Andersson Annica Andersson Per man 《Cereal Chemistry》2003,80(4):485-490
A high‐performance size‐exclusion chromatography system (HPSEC) was set up with detection based on the specific binding of Calcofluor to β‐glucan for determination of amount and molecular weight of β‐glucan in different cereal extracts. To calibrate the HPSEC system, a purified β‐glucan was fractionated into narrow molecular weight ranges and the average molecular weight was determined before analysis on the HPSEC system. The detector response was similar for β‐glucans from oats and barley and appeared to be independent of molecular weight. Four different methods for extraction of β‐glucan from different cereal products were tested: two alkaline, one with hot water and added α‐amylase, and one with water and added xylanase. Inactivation of endogenous β‐glucanase was crucial for the stability of the extracts, even when extracting at high temperature or pH. Yields varied widely between the different extraction methods but average molecular weight and molecular weight distribution were similar. Extraction with sodium hydroxide generally gave a higher yield and molecular weight of β‐glucan in the extracts. 相似文献
23.
Hjorth J Bjornsson G Andersen MI Caon N Cairos LM Castro-Tirado AJ Osorio MR Pedersen H Costa E 《Science (New York, N.Y.)》1999,283(5410):2073-2075
Polarization of the optical emission from GRB 990123 was measured on 24.17 January 1999 universal time with the Nordic Optical Telescope. An upper limit of 2.3% on the linear polarization was found. Accurate polarization measurements provide important clues to the blast wave geometry and magnetic field structure of gamma-ray bursts (GRBs). The lack of detectable polarization for GRB 990123 indicates that the optical afterglow was produced by a blast wave of unknown geometry with an insignificant coherent magnetic field or by a beamed outflow at high Lorentz factor seen at a small viewing angle. Such a collimated jet would help solve the problem of energy release in this exceptionally luminous cosmological burst. 相似文献
24.
Tove Hylgaard 《Biological conservation》1980,19(1):15-25
The resilience of plant communities to disturbance can be characterized by the ability of species and life-forms to recover, provided that the desired degree of naturalness is present. Results of a case study in two ecological types of Danish sand dunes, the grey and the white dune, show that dominant growth morphology and initial pattern of recovery are inter-related. The propagation of above-ground organs leads to progressive lateral recovery, while subterranean proliferation by means of rhizomes leads to erratic recovery. Species behave in different ways depending on the environment, and patches of bare ground generally grow over slowly, unlike well-established patches of vegetation where environmental conditions are more suitable. Because of this change of structure, vegetation recovery is not assessable by traditional recording of individual factors such as number of species or percentage cover, and a list of the key factors involved is given. The erratic pattern of recovery of rare species stresses the importance of long-term recording of vegetation to assess recovery. 相似文献
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26.
Meister S Plouffe DM Kuhen KL Bonamy GM Wu T Barnes SW Bopp SE Borboa R Bright AT Che J Cohen S Dharia NV Gagaring K Gettayacamin M Gordon P Groessl T Kato N Lee MC McNamara CW Fidock DA Nagle A Nam TG Richmond W Roland J Rottmann M Zhou B Froissard P Glynne RJ Mazier D Sattabongkot J Schultz PG Tuntland T Walker JR Zhou Y Chatterjee A Diagana TT Winzeler EA 《Science (New York, N.Y.)》2011,334(6061):1372-1377
Most malaria drug development focuses on parasite stages detected in red blood cells, even though, to achieve eradication, next-generation drugs active against both erythrocytic and exo-erythrocytic forms would be preferable. We applied a multifactorial approach to a set of >4000 commercially available compounds with previously demonstrated blood-stage activity (median inhibitory concentration < 1 micromolar) and identified chemical scaffolds with potent activity against both forms. From this screen, we identified an imidazolopiperazine scaffold series that was highly enriched among compounds active against Plasmodium liver stages. The orally bioavailable lead imidazolopiperazine confers complete causal prophylactic protection (15 milligrams/kilogram) in rodent models of malaria and shows potent in vivo blood-stage therapeutic activity. The open-source chemical tools resulting from our effort provide starting points for future drug discovery programs, as well as opportunities for researchers to investigate the biology of exo-erythrocytic forms. 相似文献
27.
Hans K. Strand Tove K. Hansen Arvid Pedersen Inger Britt Falk-Petersen Victor øiestad 《Aquaculture International》1995,3(1):1-10
Wolffish (Anarhichos lupus) larvae were first fed in a low water-level raceway system, with two new types of formulated dry feed diets. Water level in the rearing tank was 1.5 cm. The fish showed a high preference for feeding from the surface. During the first week the fish experienced a drop in dry weights. The highest SGR of 5.8% was obtained between day 35–60. The best feeding regime gave a survival rate of 82 (2.5)%. Results indicate failure to initiate feeding as a main cause of mortality in the fed groups. Death by starvation occurred after 30–40 days. It is speculated whether the large difference in growth rates between the two feeding regimens is due to differences in carbohydrate levels between the two feed types. The rearing tank technology proved, with minor adjustments, to be self-cleaning and well suited for first feeding of wolffish. 相似文献
28.
Matts Lindbladh Anna-Lena Axelsson Tove Hultberg Jörg Brunet Adam Felton 《Scandinavian Journal of Forest Research》2014,29(7):686-696
Mixed or broadleaf forests were once common in many regions of Northern Europe, whereas today conifers often dominate. The aim of the study was to investigate the spatial and temporal patterns and processes which underlie this transition to Picea abies dominance in southern Sweden. We use recently developed paleoecological methods to determine long-term changes in the relative abundance of tree species, and digitalized National Forest Inventory (NFI) databases to assess more recent changes in the spatial coverage of Picea throughout the region. The novel combination of the two databases reveals that Picea became a widespread and abundant species in many parts of southern Sweden around 1000 years ago. After a brief decline in abundance starting around 500 years ago, NFI data indicate a rapid increase in the volume of Picea between 1920 and 1950, prior to the large-scale introduction of Picea-dominated plantation forests. The available evidence suggests that abandonment of forest grazing and slash-and-burn cultivation, as well as selection cutting benefited the natural establishment and growth of Picea during the first half of the twentieth century. Hence, prior to the impacts of industrialized forestry that began in the 1950s, other processes were already favouring increased Picea abundance. 相似文献
29.
Textile sound absorbents are getting more and more popular on the market as noise reduction is a major requirement for human comfort today. In this paper we focus on a new textile material for sound absorption, by investigating the acoustic characteristics of nanofibers. Through impedance tube method we measured the sound absorption coefficients of multiple layers of nanofiber webs and compared those with microfiber materials per fabric weight. We also examined the effect of layers of nanofiber webs on regularfiber knitted fabric on sound absorption. The test results showed that the sound absorption coefficients of nanofiber layers were superior that of microfiber fabrics in the frequency range 1000–4000 Hz. In this range, the sound absorption of nanofiber webs improved with numbers of layers. Also, adding nanofiber web plies to regularfiber fleece increased the sound absorption coefficient with 85 % at 4000 Hz. From our results we could observe differences in the sound absorption coefficients between two test methods, which are higher absorbance coefficients through the reverberation room method than impedance tube method. 相似文献
30.
Since 1947, the development of greater Copenhagen has followed a plan that divided the city into a centre and five urban ‘fingers’. The ‘Finger Plan’ has constituted an important part of the planning framework, albeit informally. Under this plan, four green wedges and three green rings, located between the urban ‘fingers’, form a multifunctional recreational landscape of high value to the citizens. In 2006, the Greater Copenhagen Authority put forward a proposal for the enlargement of the existing green wedges and the addition of a new fourth green ring. In order to achieve this plan, detailed mapping of recreational opportunities was needed. Based on existing planning approaches combined with theoretical and empirical studies on preferences, use, and composition of green spaces, a method for monitoring and analyzing recreational experiences using seven specific categories was adapted and further developed to Danish conditions and applied to land use categories in greater Copenhagen. Areas that comprised one or more recreational experience values were designated by use of GIS techniques and map-based indicators for each of the seven ‘experience classes’ (wilderness; feeling of the forest; panoramic views, water, and scenery; biodiversity and land form; cultural history; activity and challenge; service and gathering). For incorporation into the regional and municipal planning policy, the seven experience classes were transformed into GIS, creating a decision support system for use at municipal and regional levels in order to facilitate future planning of the recreational landscape in greater Copenhagen. The method proved capable of pointing out important areas for recreational development in the enlarged but not yet developed areas. Further, the division of the recreational potential into seven classes makes possible site-specific development that utilizes existing potential. 相似文献