链脲佐菌素诱导Brown Norway大鼠糖尿病视网膜病变模型的建立

目的:探索在BN大鼠鼠眼建立糖尿病视网膜病变(DR)动物模型的方法。方法:40只成年健康雄性BN大鼠(80只眼)随机分为实验组和对照组,每组20只。实验组大鼠高脂饲料喂养1个月后,链脲佐菌素(STZ)建立糖尿病大鼠高血糖状态,于造模前、造模后24 h、72 h、1周多次测随机血糖,筛选出糖尿病(DM)大鼠。模型建立观察1周后,开始计算DM病程。观察时间点为DM病程1、2、3、6个月,观察大鼠的一般形态学及行为学改变,测血糖、体质量,行荧光素钠眼底造影(FFA),取鼠眼行HE染色,观察其视网膜组织学改变。结果:实验组BN大鼠总成模率为100%,死亡率为15%;正常组大鼠无死亡。随着病程的进展,实验组与对照组大鼠在血糖、体质量、大体形态及视网膜微循环组织形态变化等方面,差异有统计学意义。结论:STZ诱导的BN大鼠DR模型大体表现与DM患者的临床表现相似,视网膜组织形态学改变与DR患者类似,相较于无色素SD大鼠,BN大鼠视网膜色素的存在更类似于人类视网膜,应用范围更广。

Drought can favour the growth of small in relation to tall trees in mature stands of Norway spruce and European beech

Background: Climate change triggered many studies showing that trends and events of environmental conditions can reduce but also accelerate growth at the stand and individual tree level. However, it is still rather unknown how climate change modifies the growth partitioning between the trees in forest stands.Methods: Based on long-term girth-tape measurements in mature monospecific and mixed-species stands of Norway spruce(Picea abies(L.) Karst.) and European beech(Fagus sylvatica L.) we traced the effect of the severe droughts in 2003 and 2015 from the stand down to the tree level.Results: Stand growth of Norway spruce decreased by about 30% in the once-in-a-century drought 2015, while European beech was much more drought resistant. Water availability generally amplified size-asymmetric growth partitioning. Especially in case of Norway spruce water availability primarily fostered the growth of predominant trees, whereas drought favoured the growth of small trees at the expense of the predominant ones. We could not detect significant differences between mixed and monospecific stands in this regard.Conclusions: The drought-induced reallocation of growth in favour of small trees in case of spruce may result from its isohydric character. We hypothesize that as small trees are shaded, they can benefit from the reduced water consumption of their sun-exposed taller neighbours. In case of beech, as an anisohydric species, tall trees suffer less and smaller trees benefit less under drought. The discussion elaborates the consequences of the water dependent growth allocation for forest monitoring, growth modelling, and silviculture.

Incorporating shape constraints in generalized additive modelling of the height-diameter relationship for Norway spruce

Background： Measurements of tree heights and diameters are essential in forest assessment and modelling. Tree heights are used for estimating timber volume, site index and other important variables related to forest growth and yield, succession and carbon budget models. However, the diameter at breast height （dbh） can be more accurately obtained and at lower cost, than total tree height. Hence, generalized height-diameter （h-d） models that predict tree height from dbh, age and other covariates are needed. For a more flexible but biologically plausible estimation of covariate effects we use shape constrained generalized additive models as an extension of existing h-d model approaches. We use causal site parameters such as index of aridity to enhance the generality and causality of the models and to enable predictions under projected changeable climatic conditions. Methods： We develop unconstrained generalized additive models （GAM） and shape constrained generalized additive models （SCAM） for investigating the possible effects of tree-specific parameters such as tree age, relative diameter at breast height, and site-specific parameters such as index of aridity and sum of daily mean temperature during vegetation period, on the h-d relationship of forests in Lower Saxony, Germany. Results： Some of the derived effects, e.g. effects of age, index of aridity and sum of daily mean temperature have significantly non-linear pattern. The need for using SCAM results from the fact that some of the model effects show partially implausible patterns especially at the boundaries of data ranges. The derived model predicts monotonically increasing levels of tree height with increasing age and temperature sum and decreasing aridity and social rank of a tree within a stand, The definition of constraints leads only to marginal or minor decline in the model statistics like AIC An observed structured spatial trend in tree height is modelled via 2-dimensional surface fitting. Conclusions： We demonstrate that the SCAM approach allows optimal regression modelling flexibility similar to the standard GAM but with the additional possibility of defining specific constraints for the model effects. The longitudinal character of the model allows for tree height imputation for the current status of forests but also for future tree height prediction.

Longitudinal height-diameter curves for Norway spruce, Scots pine and silver birch in Norway based on shape constraint additive regression models

Background： Generalized height-diameter curves based on a re-parameterized version of the Korf function for Norway spruce （Piceo abies （L.） Karst.）, Scots pine （Pinus sylvestris L.） and silver birch （Betula pendula Roth） in Norwa are presented. The Norwegian National Forest Inventory （NFI） is used as data base for estimating the model parameters. The derived models are developed to enable spatially explicit and site sensitive tree height imputatio in forest inventories as well as future tree height predictions in growth and yield scenario simulations. Methods： Generalized additive mixed models （gamm） are employed to detect and quantify potentially non-linear effects of predictor variables. In doing so the quadratic mean diameter serves as longitudinal covariate since stand ag as measured in the NFI, shows only a weak correlation with a stands developmental status in Norwegian forests. Additionally the models can be locally calibrated by predicting random effects if measured height-diameter pairs are available. Based on the model selection of non-constraint models, shape constraint additive models （scare） were fit tc incorporate expert knowledge and intrinsic relationships by enforcing certain effect patterns like monotonicity. Results： Model comparisons demonstrate that the shape constraints lead to only marginal differences in statistical characteristics but ensure reasonable model predictions. Under constant constraints the developed models predict increasing tree heights with decreasing altitude, increasing soil depth and increasing competition pressure of a tree. / two-dimensional spatially structured effect of UTM-coordinates accounts for the potential effects of large scale spatial correlated covariates, which were not at our disposal. The main result of modelling the spatially structured effect is lower tree height prediction for coastal sites and with increasing latitude. The quadratic mean diameter affects both the level and the slope of the height-diameter curve and both effects are positive. Conclusions： In this investigation it is assumed that model effects in additive modelling of height-diameter curves which are unfeasible and too wiggly from an expert point of view are a result of quantitatively or qualitatively limited data bases. However, this problem can be regarded not to be specific to our investigation but more general since growth and yield data that are balanced over the whole data range with respect to all combinations of predictor variables are exceptional cases. Hence, scare may provide methodological improvements in several applications by combining the flexibility of additive models with expert knowledge.

Characterisation of Na-metasomatism in the Sveconorwegian Bamble Sector of South Norway

Na-metasomatism in the form of albitisation is regionally extensive in the Precambrian crust of southern Scandinavia and is particularly widespread in the Bamble Sector, the Kongsberg-Modum Sector and the Norwegian part of the Mylonite Zone. Sites of albitisation outside these belts are associated with hy- drothermal breccia pipes and fracture-bound alteration. The albitites are composed of near end-member sodic plagioclase （Ano 5Ab94-99） with minor carbonate （calcite and dolomite）, rutile, clinopyroxene （En30Fs21-23W047 49）, amphibole （edenite-pargasite）, quartz, titanite, tourmaline, epidote （Fe3＋ - 0.20 -0.85 a.p.f.u） and chlorite （Mg# = 0.81-0.89）. The albitites have been studied in detail in the region around the town of Kragem, and are described as albitisation along veins, as breccias, alhitic felsites, massive carbonate-bearing albitites and megascale clinopyroxene-titanite-bearing albitite. The strong fluid control on their formation is illustrated by the veining and mineral replacement reactions, showing fluid transport by a H20-CO2 fluid rich in Na, depleting Fe and Mg from the host rock, in accordance with calculated mass transfer. A study of the mineralogical replacement reactions in combination with a regional compilation has demonstrated the relationship between metasomatic processes and the for- mation of apatite, ruti｜e and Fe deposits. The albitites occur spatially associated with other metasomatic rocks such as scapolitised metagabbros. We document that metasomatism is an important mineral- and rock-forming process in the continental crust, which in the Bamble Sector is a part of the tectonome- tamorphic evolution of the Sveconorwegian orogen.

Erosion response to anthropogenic activity and climatic changes during the Holocene: case studies in northwestern China and southern Norway

Soil erosion assessment and prediction play critical roles in addressing problems associated with erosion control or soil conservation. The past dynamics of soil erosion can provide valuable information for us to understand the relations of soil erosion to environmental change and anthropogenic activity. The present paper has compared Holocene climatic changes in northwestern China with those in southern Norway, and investigated the past dynamics of erosion activity during the Holocene. Modern soil erosion on the Loess Plateau is a combination of the intensive natural erosion and human-induced erosion, the latter being four times greater than the former. Because of global warming and increasing human activities, climate on the Loess Plateau is becoming dryer and more unstable, causing an enhanced erosion problem and water scarcity. In the arctic-alpine region of southern Norway, however, the global warming and regional wetting caused expansion of the largest European ice cap. This has accentuated the erosion in that region, with a higher frequency of avalanches and debris flows.

Crown Morphology of Norway Spruce from Usual Tree Measurements

The crown morphology of Norway spruce (Picea abies Karst) was studied from 617 sample trees. In order to model branch and crown descriptors the linear and nonlinear regression methods were extensively used. Results show that the branch length can be fairly well predicted from the distance to the apex of the tree and that the branch spread has a high correlation with the branch length and the insertion angle. Models have been set up to predict the crown ratio, height to the base of the living crown, height to the first living branch and the height to the first dead branch from the usual whole-tree measurements, namely diameter at breast height total height and total age.

Examining approaches for modeling individual tree growth response to thinning in Norway spruce

Using periodic measurements from permanent plots in non-thinned and thinned Norway spruce(Picea abies(L.)H.Karst.)stands in Norway,individual-tree growth models were developed to predict annual diameter increment,height increment,and height to crown base increment.Based on long-term data across a range of thinning regimes and stand conditions,alternative approaches for modeling response to treatment were assessed.Dynamic thinning response functions in the form of multiplicative modifiers that predict no effect at the time of thinning,a rapid increase followed by an early maximum before the effect gradually declines to zero could not be fitted to initially derived baseline models without thinning related predictors.However,alternative approaches were used and found to perform well.Specifically,indicator variables representing varying time periods after thinning were statistically significant and behaved in a robust manner as well as consistent with general expectations.In addition,they improved overall prediction accuracy when incorporated as fixed effects into the baseline models for diameter and height to crown base increment.Further,more simply,including exponentially decreasing multiplicative thinning response functions improved prediction accuracy for height increment and height to crown base increment.Irrespective of studied attribute and modelling approach,improvement in performance of these extended models was relatively limited when compared to the corresponding baseline models and more pronounced in trees from thinned stands.We conclude that the largely varying and often multi-year measurement intervals of the periodic data used in this study likely prevented the development of more sophisticated thinning response functions.However,based on the evaluation of the final models’overall performance such complex response functions may not to be necessary to reliably predict individual tree growth after thinning for certain conditions or species,which should be further considered in future analyses of similar nature.

Cost-effectiveness of lutetium(^177Lu)oxodotreotide vs everolimus in gastroenteropancreatic neuroendocrine tumors in Norway and Sweden

BACKGROUND Gastroenteropancreatic neuroendocrine tumors(GEP-NETs)represent a relatively rare and heterogenous group of tumors.Currently available treatment options for patients with progressive GEP-NETs include lutetium(177 Lu)oxodotreotide(177 LuDotatate)and everolimus[as well as sunitinib for patients with pancreatic NETs(P-NETs)].AIM To perform a health economic analysis to determine the cost-effectiveness of 177 LuDotatate compared with everolimus in patients with unresectable or metastatic midgut-NETs or P-NETs in both Sweden and Norway.METHODS Simulations were performed using a three-state partitioned survival model and analyses were performed separately for patients with midgut-NETs and P-NETs.Clinical input data were sourced from an indirect comparison that utilized survival data from clinical trials of 177 Lu-Dotatate and everolimus.The analyses were performed from the healthcare payer perspective over a time horizon of 20 years.For Sweden,future costs and clinical outcomes were discounted at 3%per annum.For Norway,a discount rate of 4%per annum was applied.RESULTS For Sweden,improved survival outcomes and higher lifetime costs with 177 LuDotatate resulted in an incremental cost-effectiveness ratio(ICER)of SEK 391194 per quality-adjusted life year(QALY)gained for midgut NETs and SEK 16764 per QALY gained for P-NETs for 177 Lu-Dotatate compared with everolimus.For Norway,the corresponding ICERs were NOK 244444 per QALY gained and NOK 106451 per QALY gained,respectively.One-way sensitivity analyses revealed that the results were most sensitive to changes in drug acquisition costs and health state utility values.CONCLUSION In both Sweden and Norway,from a healthcare provider perspective,177 LuDotatate is likely to be considered cost-effective relative to everolimus for the treatment of patients with unresectable or metastatic,progressive midgut-NETs or P-NETs.

Genetic variation of Norway spruce clones regarding their natural durability, physical and chemical properties

Genetic variation of ten Norway spruce (Picea abies (L.) Karst.) clones regarding their decay resistance against brown rot fungi, as well as physical and chemical properties of clones were investigated. 31- year-old spruce clones: 26, 31, A10, A15, A7, B10, B15, B6, V7, V9 were selected across Latvia. The stem diameters of spruce clones varied between 13.0 and 20.9 cm. The wood density of clones ranged from 361 to 443 kg/m3. Klason lignin content, depending on the clone, was between 27.0%-28.9%. Cellular UV microspectrophotometry of the non-infected tracheids displayed the typical lignin distribution with highest absorbance values in the cell corners (abs280 nm 0.80) and compound middle lamellae (abs280 nm 0.48), while secondary wall showed lower lignin absorbance values (abs280 nm0.29 - 0.35). The deposition of phenolic extractives in ray parenchyma and epithelial cells of resin canals were emphasized by a significantly higher UV-absorbance (abs280 nm 0.68 to 0.78) when compared to the cell wall associated lignin. The content of acetone-soluble extractives of spruce clones varied between 1.1% - 1.8%. The x-value (natural durability) for all spruce clones after exposure to C. puteana and P. placentawas >0.90 (durability class 5, not durable). Most of clones after degradation by G. trabeum had x-value > 0.90 with exception of clones B15 and V9 that showed x-value ≤ 0.90 (durability class 4, slightly durable). Natural durability of spruce clones did not correlate with stem diameter, density, content of lignin and extractives.

COMPULSORY EDUCATION IN NORWAY Notes from a visit in September 1996

This paper tries to give an outline of the Norwegian educational system for primary schooland middle school and as understood by me during my visit to Vorway in September 1996. Myunderstanding is based on a introduction meeting in the ministry of Education, Research andReligion, and through meetings and talks with representatives for "Norges skoleforbund"(Teacher’s association of Norway)and personal talks with teachers.

Checking of Radially Sawn Scots Pine and Norway Spruce Wood

In exterior use, wood is subjected to weathering that causes checking and other deterioration in the appearance and technical properties. We studied quantitatively the surface checking of radially and tangentially sawn specimens of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies Karst.) wood in a cyclic climate chamber test. The results strongly suggested that the sawing direction determines the checking performance of both Scots pine and Norway spruce wood. The radial surface of Scots pine specimens had 62% less checks than the tangential one, and the cumulative area of checks was 74% smaller. For Norway spruce, the respective figures were: 83% less in the check number and 91% less in the check area. Different from pine, in spruce specimens the checks of radial surface were significantly smaller. Thus, spruce timber gained clearly more about radial sawing pattern. The effect of annual ring width was similar for pine and spruce: the reduction in annual growth worsened the checking. The increase in density worsened the checking of spruce but did not change the performance of pine. In pine wood, the increase of heartwood proportion reduced the fluctuation of moisture content and the formation of checks.

Genetic diversity and background pollen contamination in Norway spruce and Scots pine seed orchard crops

Seed orchards are the key link between tree breeding and production forest for conifer trees.In Sweden,Scots pine and Norway spruce seed orchards currently supply ca.85%of seedlings used in annual reforestation.The functionality of these seed orchards is thus crucial for supporting long-term production gain and sustainable diversity.We conducted a large-scale genetic investigation of pine and spruce orchards across Sweden using genotyping-by-sequencing.We genotyped 3,300 seedlings/trees from six orchards and 10 natural stands to gain an overview of mating structure and genetic diversity in orchard crops.We found clear differences in observed heterozygosity(HO)and background pollen contamination(BPC)rates between species,with pine orchard crops showing higher HO and BPC than spruce.BPC in pine crops varied from 87%at young orchard age to 12%at mature age,wherease this rate ranged between 27%−4%in spruce crops.Substantial variance in parental contribution was observed in all orchards with 30%−50%parents contibuting to 80%of the progeny.Selfing was low(2%−6%)in all seed crops.Compared to natural stands,orchard crops had slightly lower HO but no strong signal of inbreeding.Our results provide valuable references for orchard management.

Effect of temperature on the leaching of heavy metals from nickel mine tailings in the arctic area,Norway

The leaching of heavy metals from tailings deposit due to the oxidation of sulphidic tailings and formation of acidic leachate is considered a high risk to the surrounding environment.Temperature plays an important role in the leaching of heavy metals from tailings in changing acid-based environment,especially in the Arctic area.To investigate how the temperature variation affected metal release from tailings in the Arctic area,a series of column leaching experiments was conducted under four temperature situations(5°C,10°C,14°C and 18°C).Physicochemical properties,Fe,Zn,Ni and Mn concentrations of leachates at each cycle were measured,and multivariate statistical analysis was applied to research the effect of temperature on heavy metals leaching from tailings in the Arctic area.The results showed that higher temperatures encouraged tailings to oxidation and sulfuration of and promoted heavy metal release from the tailings through precipitation and erosion.Ni,Zn and Mn have similar releasing resources from tailings and positive correlation in the leaching activity.Rising temperature accelerated Fe leaching;Fe leaching promoted leaching of the other metals,especially of Mn.Appropriately increase temperature will accelerate oxidization and sulfidization of the tailings,promote acid generation and increase TDS and,finally,promote the release of heavy metals.Climate change,with rising temperatures increasing the risk of heavy metals leaching from the tailings,should be given greater attention.Keeping tailings away from the appropriate temperature and in a higher alkalinity is a good method to control the leaching of heavy metals from tailings.

Norway spruce(Picea abies) laccases:Characterization of a laccase in a lignin-forming tissue culture

Secondarily thickened cell walls of water-conducting vessels and tracheids and support-giving sclerenchyma cells contain lignin that makes the cell walls water impermeable and strong. To what extent laccases and peroxidases contribute to lignin biosynthesis in muro is under active evaluation. We performed an in silico study of Norway spruce （Picea abies （L.） Karst.） laccases utilizing available genomic data. As many as 292 laccase encoding sequences （genes, gene fragments, and pseudogenes） were detected in the spruce genome. Out of the 112 genes annotated as laccases, 79 are expressed at some level. We isolated five fun-length laccase cDNAs from developing xylem and an extracellular lignin-forming cell culture of spruce. In addition, we purified and biochemically characterized one culture medium laccase from the lignin-forming cell culture. This laccase has an acidic pH optimum （pH 3.8-4.2） for coniferyl alcohol oxidation. It has a high affinity to coniferyl alcohol with an apparent Km value of 3.5μM; however, the laccase has a lower catalytic efficiency （Vmax/Km） for coniferyl alcohol oxidation compared with some purified culture medium peroxidases. The properties are discussed in the context of the information already known about laccases/coniferyl alcohol oxidases of coniferous plants.

Derivation of embryonic stem cells from Brown Norway rats blastocysts

Knockout Brown Norway （BN） rat could be a useful disease model for human disorders,however,a failure to derive embryonic stem （ES） cells disturbs the further development of the model.In this study,we reported a case of successful derivation of the BN rat ES cells with the derivation efficiency comparable to that of Sprague Dawley （SD） rats.The BN rat ES cells expressed the key transcription factors,and were able to form embryonic bodies （EBs） when being differentiated in vitro.After injecting the BN rat ES cells into the SD rat blastocysts,high-contribution chimeric rats were generated and could survive to their adulthood.Our success in generating pluripotent rat ES cells will benefit the generation of the knockout rats in the future.

Cell Wall Lignin is Polymerised by Class Ⅲ Secretable Plant Peroxidases in Norway Spruce

Class Ⅲ secretable plant peroxidases occur as a large family of genes in plants with many functions and probable redundancy. In this review we are concentrating on the evidence we have on the catalysis of lignin polymerization by class Ⅲ plant peroxidases present in the apoplastic space in the xylem of trees. Some evidence exists on the specificity of peroxidase isozymes in lignin polymerization through substrate specificity studies, from antisense mutants in tobacco and poplar and from tissue and cell culture lines of Norway spruce （Picea abies） and Zinnia elegans. In addition, real time （RT-）PCR results have pointed out that many peroxidases have tissue specific expression patterns in Norway spruce. Through combining information on catalytic properties of the enzymes, on the expression patterns of the corresponding genes, and on the presence of monolignols and hydrogen peroxide in the apoplastic space, we can show that specific peroxidases catalyze lignin polymerization in the apoplastic space of Norway spruce xylem.