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21.
The spectral characteristics of a widely tunable super structure grating distributed Bragg reflector (SSG-DBR) laser are investigated and the design considerations of the grating reflectors are given. By systematically adjusting the control currents of the two reflector sections and the phase section it is experimentally shown that every wavelength in an interval of 40 nm can be reached with a side-mode suppression usually better than 30 dB  相似文献   
22.
The beige mutation is a murine autosomal recessive disorder, resulting in hypopigmentation, bleeding and immune cell dysfunction. The gene defective in beige is thought to be a homologue of the gene for the human disorder Chediak-Higashi syndrome. We have identified the murine beige gene by in vitro complementation and positional cloning, and confirmed its identification by defining mutations in two independent mutant alleles. The sequence of the beige gene message shows strong nucleotide homology to multiple human ESTs, one or more of which may be associated with the Chediak-Higashi syndrome gene. The amino acid sequence of the Beige protein revealed a novel protein with significant amino acid homology to orphan proteins identified in Saccharomyces cerevisiae, Caenorhabditis elegans and humans.  相似文献   
23.
In CHO cells transfected with the rat dopamine D2 receptor (long isoform), administration of dopamine per se elicited a concentration-dependent increase in arachidonic acid (AA) release. The maximal effect was 197% of controls (EC50=25 nM). The partial D2 receptor agonist, (-)-(3-hydroxyphenyl)-N-n-propylpiperidine [(-)-3-PPP], also induced AA release, but with somewhat lower efficacy (maximal effect: 165%; EC50=91 nM). The AA-releasing effect of dopamine was counteracted by pertussis toxin, by the inhibitor of intracellular Ca2+ release, 8-(N N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8), by excluding calcium from the medium, by the phospholipase A2 (PLA2) inhibitor, quinacrine, and by long-term pretreatment with the phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA). In addition, it was antagonized by the D2 antagonists, raclopride and (-)-sulpiride--but not by (+)-sulpiride--and absent in sham-transfected CHO cells devoid of D2 receptors. The results obtained contrast to the previous notion that dopamine and other D2 receptor agonists require the concomitant administration of calcium-mobilizing agents such as ATP, ionophore A-23187 (calcimycin), thrombin, and TRH, to influence AA release from various cell lines.  相似文献   
24.
(1) Background: The unusual accumulation of Na,K-ATPase complexes in the brush border membrane of choroid plexus epithelial cells have intrigued researchers for decades. However, the full range of the expressed Na,K-ATPase subunits and their relation to the microvillus cytoskeleton remains unknown. (2) Methods: RT-PCR analysis, co-immunoprecipitation, native PAGE, mass spectrometry, and differential centrifugation were combined with high-resolution immunofluorescence histochemistry, proximity ligase assays, and stimulated emission depletion (STED) microscopy on mouse choroid plexus cells or tissues in order to resolve these issues. (3) Results: The choroid plexus epithelium expresses Na,K-ATPase subunits α1, α2, β1, β2, β3, and phospholemman. The α1, α2, β1, and β2, subunits are all localized to the brush border membrane, where they appear to form a complex. The ATPase complexes may stabilize in the brush border membrane via anchoring to microvillar actin indirectly through ankyrin-3 or directly via other co-precipitated proteins. Aquaporin 1 (AQP1) may form part of the proposed multi-protein complexes in contrast to another membrane protein, the Na-K-2Cl cotransporter 1 (NKCC1). NKCC1 expression seems necessary for full brush border membrane accumulation of the Na,K-ATPase in the choroid plexus. (4) Conclusion: A multitude of Na,K-ATPase subunits form molecular complexes in the choroid plexus brush border, which may bind to the cytoskeleton by various alternative actin binding proteins.  相似文献   
25.
A novel gene fusion system to express and purify small recombinantproteins in Escherichia coli has been constructed. The conceptallows for affinity purification of soluble gene products bysequential albumin- and Zn2+-affinity chromatography. The dual-affinitysystem is well suited for expression of unstable proteins asonly full-length protein is obtained after purification andproteins gain proteolytic stability in the fusion protein. Herewe show that the dual-affinity approach can be used for theexpression of various unstable derivatives of a single IgG-bindingdomain based on staphylococcal protein A. Analysis of the proteolyticstabilities and the IgG-binding properties of the differentmutant proteins suggest that the model for the structure ofan IgG-binding domain must be re-evaluated.  相似文献   
26.
27.
Anaerobic digestion is a well established technology for the reduction of organic matter and stabilization of wastewater. Biogas, a mixture of methane and carbon dioxide, is produced as a useful by-product of the process. Current solid waste management at the city of Prince George is focused on disposal of waste and not on energy recovery. Co-digestion of fresh fruit and vegetable waste with sewer sludge can improve biogas yield by increasing the load of biodegradable material. A six week full-scale project co-digesting almost 15,000 kg of supermarket waste was completed. Average daily biogas production was found to be significantly higher than in previous years. Digester operation remained stable over the course of the study as indicated by the consistently low volatile acids-to-alkalinity ratio. Undigested organic material was visible in centrifuged sludge suggesting that the waste should have been added to the primary digester to prevent short circuiting and to increase the hydraulic retention time of the freshly added waste.  相似文献   
28.
分块云计算     
Jimmy  Nilsson  郭晓刚 《程序员》2009,(6):63-66
Jimmy Nilsson在过去数年间观察到一种架构风格正慢慢流行,通过对过去数年的总结,对过往的痛苦自省,他将这种新的架构风格做了总结。  相似文献   
29.
The present work presents mathematical model for the estimation of sulphide capacities. The sulphide capacity, CS is expressed as (1) where ΔG0 is the standard Gibbs energy change for the reaction, (2) ξ, being a function of both temperature and composition, is characterized by the system under consideration. By optimizing ξ, the sulphide capacities could be estimated as functions of temperature and composition. The slag composition is described using a modified Temkin approach, where complex polymeric ions are considered as dissociated to simple species. The model has been applied to the binary systems CaO-SiO2, MnO-SiO2 as well as the CaO-MnO-SiO2 ternary system. The results show that reliable predictions of the sulphide capacities can be obtained using the present model.  相似文献   
30.
Social media plays an increasingly prominent role in the interaction between impact assessments and society. Impact assessment is thus becoming part of social networks that are claimed to be able to improve interaction between actors in impact assessment processes. By investigating the use of social media in impact assessment and planning processes of national linear infrastructure development, we explore how social media impinge on participatory practices and how the potential of social media is realized in the current use related to public participation processes. The study focuses on experiences among national developers working in road, rail, electricity, gas, and metro infrastructures in Denmark. The article shows that the current use of social media in public participatory practices is limited to branding and on-way communication and that the increasing use of social media in linear infrastructure planning gives rise to a variety of concerns among developers that are related to especially organizational cultures, perception of the target groups, and prioritization of resources.  相似文献   
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