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41.
William Whittaker Laura Anselmi S?ren Rud Kristensen Yiu-Shing Lau Simon Bailey Peter Bower Katherine Checkland Rebecca Elvey Katy Rothwell Jonathan Stokes Damian Hodgson 《PLoS medicine》2016,13(9)
BackgroundHealth services across the world increasingly face pressures on the use of expensive hospital services. Better organisation and delivery of primary care has the potential to manage demand and reduce costs for hospital services, but routine primary care services are not open during evenings and weekends.Extended access (evening and weekend opening) is hypothesized to reduce pressure on hospital services from emergency department visits. However, the existing evidence-base is weak, largely focused on emergency out-of-hours services, and analysed using a before-and after-methodology without effective comparators.ConclusionsThe study found that extending access was associated with a reduction in emergency department visits in the first 12 months. The results of the research have already informed the decision by National Health Service England to extend primary care access across Greater Manchester from 2016. However, further evidence is needed to understand whether extending primary care access is cost-effective and sustainable. 相似文献
42.
43.
Jens Peder Jensen Erik Jeppesen Peter Kristensen Peter Bondo Christensen Martin Sndergaard 《International Review of Hydrobiology》1992,77(1):29-42
A detailed mass balance on nitrogen was carried out in shallow and hypertrophic Lake Søbygård during 4.5 years before through 2.5 years after a 36 % reduction in nitrogen loading. Annual mean loss rate of nitrogen was 159–229 mg N m−2 d−1 before the loading reduction and 125 mg N m−2 d−1 after. In spite of a short hydraulic retention time (18–27 days) the proportion of nitrogen loading lost in the lake was high (38–53 %) and not affected by changes in loading. Calculated denitrification accounted for 86–93% of the loss rate, while 7–14% was permanently buried. Marked seasonal variations in the loss percentage were found during the season, ranging from 23 % in first quarter to 65 % in third quarter. The seasonal variation in the loss percentage of nitrogen showed a hysteresis like relationship to temperature, with a high percentage in fourth quarter. This suggests that the amount of available substrate, which mainly consists of sedimentated phytoplankton, accumulated during summer, is an important regulating factor. The ability of various published input-output models to predict the observed changes in in-lake nitrogen concentration in Lake Søbygård was tested. This study has further confirmed that small lakes with short retention and high nitrogen loading may significantly reduce the nitrogen loading of downstream aquatic environments. 相似文献
44.
David C. Lees Rodolphe Rougerie Christof
Zeller‐Lukashort Niels P. Kristensen 《Zoologica scripta》2010,39(6):642-661
Lees, D. C., Rougerie, R., Zeller‐Lukashort, C. & Kristensen, N. P. (2010). DNA mini‐barcodes in taxonomic assignment: a morphologically unique new homoneurous moth clade from the Indian Himalayas described in Micropterix (Lepidoptera, Micropterigidae). —Zoologica Scripta, 39, 642–661. The first micropterigid moths recorded from the Himalayas, Micropterix cornuella sp. n. and Micropterix longicornuella sp. n. (collected, respectively, in 1935 in the Arunachel Pradesh Province and in 1874 in Darjeeling, both Northeastern India) constitute a new clade, which is unique within the family because of striking specializations of the female postabdomen: tergum VIII ventral plate forming a continuous sclerotized ring, segment IX bearing a pair of strongly sclerotized lateroventral plates, each with a prominent horn‐like posterior process. Fore wing vein R unforked, all Rs veins preapical; hind wing devoid of a discrete vein R. The combination of the two first‐mentioned vein characters suggests close affinity to the large Palearctic genus Micropterix (to some species of which the members of the new clade bear strong superficial resemblance). Whilst absence of the hind wing R is unknown in that genus, this specialization is not incompatible with the new clade being subordinate within it. A 136‐bp fragment of Cytochrome oxidase I successfully amplified from both of the 75‐year‐old specimens strongly supports this generic assignment. Translated to amino acids, this DNA fragment is highly diagnostic of this genus, being identical to that of most (16 of the 26) Micropterix species studied comparatively here, 1–4 codons different from nine other species (including Micropterix wockei that in phylogenetic analyses we infer to be sister to other examined species), whilst 7–15 codons different to other amphiesmenopteran genera examined here. A dating analysis also suggests that the large clade excluding M. wockei to which M. cornuella belongs appeared <31 million years ago. These findings encourage discovery of a significant radiation of Micropterix in the Himalayan region. Our analysis has more general implications for testing the assignment of DNA mini‐barcodes to a taxon, in cases such as museum specimens where the full DNA barcode cannot be recovered. 相似文献
45.
Modulation of A-NK cell rigidity: In vitro characterization and in vivo implications for cell delivery 总被引:1,自引:0,他引:1
The delivery of cells to specific regions of the vasculature is a critical step in many therapeutic strategies. These include the packaging of DNA or RNA in cell "vehicles" for delivery to tissues, the reconstitution of differentiated cells to an organ using embryonic stem cells, and the enhancement of the immune response using effector lymphocytes. In most cases, these cells must be injected systemically. Unfortunately, ex vivo manipulation or activation can affect cell visco-elastic properties, making it difficult for the injected cells to traverse capillary beds. Compounding the problem is the fact that common agents used in the laboratory for increasing cell deformability generally have adverse side effects on the therapeutic potential of the cells. Using micropipet aspiration techniques, cytotoxicity assays and in vivo trafficking studies we show that: (1) the rigidity of injected effector cells directly affects resistance to passage through tissue; (2) modulation of cytoskeletal organization can be used to decrease cell rigidity, but can also compromise therapeutic efficacy; and (3) thioglycollate, an agent which does not influence effector lymphocyte cytotoxic activity, reduces cell rigidity and entrapment in the lungs. 相似文献
46.
Dimeric fragment of the insulin receptor alpha-subunit binds insulin with full holoreceptor affinity
The insulin receptor (IR) is a dimeric receptor, and its activation is thought to involve cross-linking between monomers initiated by binding of a single insulin molecule to separate epitopes on each monomer. We have previously shown that a minimized insulin receptor consisting of the first three domains of the human IR fused to 16 amino acids from the C-terminal of the alpha-subunit was monomeric and bound insulin with nanomolar affinity (Kristensen, C., Wiberg, F. C., Sch?ffer, L., and Andersen, A. S. (1998) J. Biol. Chem. 273, 17780-17786). To investigate the insulin binding properties of dimerized alpha-subunits, we have reintroduced the domains containing alpha-alpha disulfide bonds into this minireceptor. When inserting either the first fibronectin type III domain or the full-length sequence of exon 10, the receptor fragments were predominantly secreted as disulfide-linked dimers that both had nanomolar affinity for insulin, similar to the affinity found for the minireceptor. However, when both these domains were included we obtained a soluble dimeric receptor that bound insulin with 1000-fold higher affinity (4-8 pm) similar to what was obtained for the solubilized holoreceptor (14-24 pm). Moreover, dissociation of labeled insulin from this receptor was accelerated in the presence of unlabeled insulin, demonstrating another characteristic feature of the holoreceptor. This is the first direct demonstration showing that the alpha-subunit of IR contains all the epitopes required for binding insulin with full holoreceptor affinity. 相似文献
47.
Sequential dimerization of human zipcode-binding protein IMP1 on RNA: a cooperative mechanism providing RNP stability 总被引:2,自引:1,他引:1
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Nielsen J Kristensen MA Willemoës M Nielsen FC Christiansen J 《Nucleic acids research》2004,32(14):4368-4376
Active cytoplasmic RNA localization depends on the attachment of RNA-binding proteins that dictate the destination of the RNA molecule. In this study, we used an electrophoretic mobility-shift assay in combination with equilibrium and kinetic analyses to characterize the assembly of the human zipcode-binding protein IMP1 on targets in the 3′-UTR from Igf-II mRNA and in H19 RNA. In both cases, two molecules of IMP1 bound to RNA by a sequential, cooperative mechanism, characterized by an initial fast step, followed by a slow second step. The first step created an obligatory assembly intermediate of low stability, whereas the second step was the discriminatory event that converted a putative RNA target into a ‘locked’ stable RNP. The ability to dimerize was also observed between members of the IMP family of zipcode-binding proteins, providing a multitude of further interaction possibilities within RNP granules and with the localization apparatus. 相似文献
48.
Purification and cloning of a Chinese red radish peroxidase that metabolise pelargonidin and forms a gene family in Brassicaceae 总被引:3,自引:0,他引:3
An anionic peroxidase RsPrx1 was purified (RZ=3.0) and characterized from roots of Chinese red radish (Raphanus sativus var. niger, Brassicaceae). The specific activity of RsPrx1 (micromol mg(-1) min(-1)) is 413.5 (ferulic acid); 258.7 (ABTS); 177.3 (caffeic acid) and 10.0 (guaiacol acid). The optimum pH is 4.0 (citrate buffer) using ABTS as substrate. RsPrx1 can utilise the red pigment present in the root, pelargonidin, as substrate and the specific activity is 93.6 micromol mg(-1) min(-1). The molecular mass of RsPrx1 is 45 kDa (denatured) and 46 kDa (native) as determined by SDS-PAGE and gel filtration, respectively. The isoelectric point (pI) determined by native IEF is 4.7 and by chromatofocusing (Mono P) is 5.1. Analysis of tryptic peptides by nanoscale liquid chromatography-tandem mass spectrometry (LC-MS/MS) covered 27% of the RsPrx1 sequence and confirmed its identity. The gene encoding RsPrx1 was cloned by PCR and the amino acid sequence showed the highest identity (82%) to peroxidase AtPrx22 and AtPrx23 from Arabidopsis thaliana and to HRPC3 and HRPE5 from horseradish, respectively. Activity-stained IEF gels show that RsPrx1 is primarily expressed in the roots in agreement with the expression profile of the orthologous genes. These five orthologous peroxidases have three introns of variable length and sequence at conserved locations between the distal and proximal histidine. The results suggest that RsPrx1 orthologs are widespread in the Brassicaceae plant family with a 15-residue-long C-terminal propeptide in common. Based on the results, we propose that RsPrx1 and orthologs are targeted to the vacuoles to modify stored anthocyanins like pelargonidin. 相似文献
49.
We aim at studying adaptation to genetic and environmental stress and its evolutionary implications at different levels of
biological organization. Stress influences cellular processes, individual physiology, genetic variation at the population
level, and the process of natural selection. To investigate these highly connected levels of stress effects, it is advisable
- if not critical - to integrate approaches from ecology, evolution, physiology, molecular biology and genetics. To investigate
the mechanisms of stress resistance, how resistance evolves, and what factors contribute to and constrain its evolution, we
use the well-defined model systems ofDrosophila species, representing both cosmopolitan species such asD. melanogaster with a known genome map, and more specialized and ecologically well described species such as the cactophilicD. buzzatii. Various climate-related stresses are used as model stresses including desiccation, starvation, cold and heat. Genetic stress
or genetic load is modelled by studying the consequences of inbreeding, the accumulation of (slightly) deleterious mutations,
hybridization or the loss of genetic variability. We present here a research plan and preliminary results combining various
approaches: molecular techniques such as microarrays, quantitative trait loci (QTL) analyses, quantitative PCR, ELISA or Western
blotting are combined with population studies of resistance to climatic and genetic stress in natural populations collected
across climatic gradients as well as in selection lines maintained in the laboratory. 相似文献
50.
Experimental designs involving repeated measurements on experimental units are widely used in physiological research. Often, relatively many consecutive observations on each experimental unit are involved and the data may be quite nonlinear. Yet evidently, one of the most commonly used statistical methods for dealing with such data sets in physiological research is the repeated-measurements ANOVA model. The problem herewith is that it is not well suited for data sets with many consecutive measurements; it does not deal with nonlinear features of the data, and the interpretability of the model may be low. The use of inappropriate statistical models increases the likelihood of drawing wrong conclusions. The aim of this article is to illustrate, for a reasonably typical repeated-measurements data set, how fundamental assumptions of the repeated-measurements ANOVA model are inappropriate and how researchers may benefit from adopting different modeling approaches using a variety of different kinds of models. We emphasize intuitive ideas rather than mathematical rigor. We illustrate how such models represent alternatives that 1) can have much higher interpretability, 2) are more likely to meet underlying assumptions, 3) provide better fitted models, and 4) are readily implemented in widely distributed software products. 相似文献