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排序方式: 共有90条查询结果,搜索用时 31 毫秒
1.
Hemminki Ari; Hoffren Anna-Marja; Takkinen Kristiina; Vehniainen Markus; Makinen Maija-Liisa; Pettersson Kim; Teleman Olle; Soderlund Hans; Teeri Tuula T. 《Protein engineering, design & selection : PEDS》1995,8(2):185-191
Europium chelates provide a non-radioactive alternative forsensitive labelling of antibodies for diagnostic immunoassays.Lysine residues at antibody surfaces are ready targets for labellingby an isothiocyanate derivative of the europium chelate (Eu3+).Here the labelling efficiency of a recombinant anti-human -fetoprotein(hAFP) Fab fragment has been improved by increasing its lysinecontent by protein engineering. Molecular modelling was usedto identify three light chain constant domain surface arginineresidues, R154, R187 and R210, which were mutated to lysineresidues. The mutations did not influence the affinity of thelysine-enriched Fab fragment and its labelling efficiency wasfound to be 40% higher than that of the wildtype Fab fragmentWith low degree of labelling, the affinities of the two Fabfragments were identical and comparable with that of the originalmonoclonal anti-hAFP IgG. With a higher degree of labellingthe affinities of both Fab fragments decreased more than thatof the intact IgG since more lysine residues are available forlabelling in the additional heavy chain constant domains ofthe larger molecule. Electrostatic adsorption and covalent immobilizationof the Fab fragments were characterized by BIAcoreTM and thelysine-enriched Fab fragment was found to be more efficientlyimmobilized to an activated carboxymethyl surface. 相似文献
2.
Hoffren Anna-Marja; Saloheimo Markku; Thomas Pamela; Overington John P.; Johnson Mark S.; Knowles Jonathan K.C.; Blundell Tom L. 《Protein engineering, design & selection : PEDS》1993,6(2):177-182
A model of the lignin peroxidase LIII of Phlebia radiata wasconstructed on the basis of the structure of cytochrome c peroxidase(CCP). Because of the low percentage of amino acid identitybetween the CCP and the lignin peroxidase LIII of Phlebia radiata,alignment of the sequences was based on the generation of atemplate from a knowledge of the 3-D structure of CCP and consensussequences of lignin peroxidases. This approach gave an alignmentin which all the insertions in the lignin peroxidase were placedat loop regions of CCP, with a 21.1% identity for these twoproteins. The model was constructed using this alignment andthe computer program COMPOSER, which assembles the model asa series of rigid fragments derived from CCP and other proteins.Manual intervention was required for some of the longer loopregions. The -helices forming the structural framework, andespecially the haem environment of CCP, are conserved in theLIII model and the core is close packed without holes. A possiblesite of the substrate oxidation at the haem edge of LIII isdiscussed. 相似文献
3.
Gelu Onose Aurelian Anghelescu Dan Blendea Vlad Ciobanu Cristina Daia Florentina Carmen Firan Mihaela Oprea Aura Spinu Cristina Popescu Anca Ionescu tefan Busnatu Constantin Munteanu 《International journal of molecular sciences》2022,23(2)
BACKGROUND: Cerebral circulation delivers the blood flow to the brain through a dedicated network of sanguine vessels. A healthy human brain can regulate cerebral blood flow (CBF) according to any physiological or pathological challenges. The brain is protected by its self-regulatory mechanisms, which are dependent on neuronal and support cellular populations, including endothelial ones, as well as metabolic, and even myogenic factors. OBJECTIVES: Accumulating data suggest that “non-pharmacological” approaches might provide new opportunities for stroke therapy, such as electro-/acupuncture, hyperbaric oxygen therapy, hypothermia/cooling, photobiomodulation, therapeutic gases, transcranial direct current stimulations, or transcranial magnetic stimulations. We reviewed the recent data on the mechanisms and clinical implications of these non-pharmaceutical treatments. METHODS: To present the state-of-the-art for currently available non-invasive, non-pharmacological-related interventions in acute ischemic stroke, we accomplished this synthetic and systematic literature review based on the Preferred Reporting Items for Systematic Principles Reviews and Meta-Analyses (PRISMA). RESULTS: The initial number of obtained articles was 313. After fulfilling the five steps in the filtering/selection methodology, 54 fully eligible papers were selected for synthetic review. We enhanced our documentation with other bibliographic resources connected to our subject, identified in the literature within a non-standardized search, to fill the knowledge gaps. Fifteen clinical trials were also identified. DISCUSSION: Non-invasive, non-pharmacological therapeutic/rehabilitative interventions for acute ischemic stroke are mainly holistic therapies. Therefore, most of them are not yet routinely used in clinical practice, despite some possible beneficial effects, which have yet to be supplementarily proven in more related studies. Moreover, few of the identified clinical trials are already completed and most do not have final results. CONCLUSIONS: This review synthesizes the current findings on acute ischemic stroke therapeutic/rehabilitative interventions, described as non-invasive and non-pharmacological. 相似文献
4.
5.
Resilience: An Evolutionary Approach to Spatial Economic Systems 总被引:5,自引:0,他引:5
The concept of resilience has received a great deal of attention in the past decades. Starting from the first fundamental definitions offered by Holling, Pimms and Perrings in an economic-ecological modeling context, the present paper explores the evolution of the resilience concept—as well as related different measures—in both a continuous and discrete time setting.From this perspective, the paper explores the relevance of the resilience concept in socio-economic systems, by focussing the attention on the relationships among resilience, transition dynamics and lock-in effects, in particular in the light of the dynamics of technological innovation diffusion and adaptive behaviour of firms. In this framework we will describe an empirical application, in which the resilience and dynamics of the West-German labour market will be investigated. This empirical illustration is offered by making use of an algorithm constructed for detecting Lyapunov exponents, so as to classify the resilience among employment sectors in our case study. 相似文献
6.
Roberto Patuelli Aura Reggiani Sean P. Gorman Peter Nijkamp Franz-Josef Bade 《Networks and Spatial Economics》2007,7(4):315-331
The analysis of complex networks has recently received considerable attention. The work by Albert and Barabási presented a
research challenge to network analysis, that is, growth of the network. The present paper offers a network analysis of the
spatial commuting network in Germany. First, we study the spatial evolution of the commuting network over time. Secondly,
we compare two spatial interaction model (SIM) specifications, in order to replicate the actual network structure. Our findings
suggest that the commuting network appeared to become more dense and clustered, while the SIMs seem to require more sophisticated
specifications, in order to replicate such a connectivity structure. 相似文献
7.
Information, communication and transport networks have always been in a state of flux, while they also influence each other. Extensive research efforts have been made to investigate the dynamics in the structure and use of networks, for example, by means of network geometries, Small-World effects and Scale-Free phenomena. We will illustrate these new developments on the basis of airline network evolution. Using Lufthansa's networks as an example, this paper aims to show the empirical relevance of various network indicators – such as connectivity and concentration – for understanding changing patterns in airline network configurations. After an extensive discussion of various statistical results, a decision-aid method, viz. multi-criteria analysis, is used to investigate the robustness of our findings. The results highlight the actual strategic choices made by Lufthansa for its own network, as well in combination with its partners in Star Alliance. 相似文献
8.
Aura Angelica Popa Eugenia Comăniţă Luminiţ Cianga C. I. Simionescu 《Polymer-Plastics Technology and Engineering》2013,52(9-10):871-884
The paper discusses the synthesis of the N,N,′-azobis(formamidopropionic) acid (AFP), along with some characteristics determined from NMR spectrum, differential thermal analysis, and DSC. The behavior of AFP acid—as well as of its analogue, N,N′-azobis(formamidoacetic) acid (AFA)—has been studied in the reaction with aromatic diamine and with bis(glycol)terephthalate, leading to azopolymers of the azopolyamide, or azopolyester, type. On employing N,N′-bis(β-hydroxyethyl) azobis-formamide (HEAF) as the azo bifunctional compound in the reaction with diphenylmethane diisocyanate, a polyurethane possessing azo groups was obtained. The structure of the azopolymers has been spectroscopically confirmed. 相似文献
9.
Tinca Buruiana Violeta Melinte Emil C Buruiana Aura Mihai 《Polymer International》2009,58(10):1181-1189
BACKGROUND: The development of polymeric nanocomposites incorporating intercalated or exfoliated layered silicate clays into the organic matrix has been substantially motivated by the significant improvements induced by the presence of the inorganic component. Moreover, understanding and controlling the dispersion of inorganic layers into segmented polyurethane matrices by means of ionic interactions, and exploiting these interactions to enhance physicomechanical behaviour, could be of great interest in the field of polymer nanocomposites. RESULTS: New cationic polyurethane elastomers were prepared starting from poly(butylene adipate)diol (Mn = 1000 g mol?1), 4,4′‐diphenylmethane diisocyanate, 1,4‐butanediol and N‐methyldiethanolamine or N,N′‐β‐hydroxyethylpiperazine, used as potential quaternizable moieties. The characterization of the polymers was achieved using specific analyses employed for the macromolecular samples (Fourier transform infrared and 1H NMR spectroscopy, thermogravimetric analysis (TGA), gel permeation chromatography). An extension of our research on polymers reinforced with organically modified montmorillonite (OM‐MMT) in order to prepare hybrid composites with improved properties was performed and the resulting materials were characterized using TGA, X‐ray diffraction, atomic force microscopy and scanning electron microscopy. Also, the mechanical properties of the cationic polyurethane/OM‐MMT composites were investigated in comparison with the pristine ionic/non‐ionic polymers and their composites containing non‐ionic polymer blended with OM‐MMT or ionic polymer and unmodified MMT. CONCLUSION: The insertion of the organically modified clay into the polymeric matrix gave an improvement of the mechanical properties of the polyurethane composites, especially the tensile strength and stiffness of the hybrid materials. Copyright © 2009 Society of Chemical Industry 相似文献
10.
In this paper, we present a collision free MAC protocol for wireless networks with smart antennas that provides proportional
service differentiation to various classes of traffic based on their respective bandwidth demand. The proposed protocol works
for diverse physical parameters such as number of interfaces at each node, number of communication frequencies, and antenna
beamwidth. To the best of our knowledge, this is the first work that provides link layer differentiated services for wireless
networks with smart antennas and explores the influence of the physical parameters and network topology on the performance
of the MAC layer.
Ashish Deopura received his B.Tech degree in Electrical Engineering from the Indian Institute of Technology Delhi, India, in 2003, and he
received his M.S. degree in Computer Systems Engineering from the University of Massachusetts Amherst, in 2005. He currently
works as a Modeling Engineer for OPNET Technologies located in Bethesda, MD
Professor Aura Ganz is the director of the Multimedia Networking Laboratory at the University of Massachusetts at Amherst. She has authored more
than 170 journal and conference papers in the areas of multimedia wireless networks, ubiquitous computing, telemedicine, and
security. She is a co-author of the book: “Multimedia Wireless Networks”, Prentice Hall, 2003. Some of her recent assignments
include: general co-chair of the IEEE UWBNETS workshop, general co-chair of the IEEE BROADMED workshop, general co-chair of
the Massachusetts 3rd Annual R&D Conference, keynote speaker at the NSF sponsored workshop in Mobile Computing, and invited
speaker at Personal and Local Wireless Network Solutions conference, and Motorola’s Wireless Communications Futures Forum,
Wireless Local Area Networks Conference. She has a PhD, MSc and BSc in Computer Science from the Technion in Israel. More
details can be found at: dvd1.ecs.umass.edu/wireless. 相似文献