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排序方式: 共有63条查询结果,搜索用时 15 毫秒
1.
Laura Nicolle Jens Casper Melanie Willimann Cline M. A. Journot Pascal Detampel Toma Einfalt Hiu Man Grisch-Chan Beat Thny Sandrine Gerber-Lemaire Jrg Huwyler 《International journal of molecular sciences》2021,22(8)
There is an increasing interest in cationic polymers as important constituents of non-viral gene delivery vectors. In the present study, we developed a versatile synthetic route for the production of covalent polymeric conjugates consisting of water-soluble depolymerized chitosan (dCS; MW 6–9 kDa) and low molecular weight polyethylenimine (PEI; 2.5 kDa linear, 1.8 kDa branched). dCS-PEI derivatives were evaluated based on their physicochemical properties, including purity, covalent bonding, solubility in aqueous media, ability for DNA condensation, and colloidal stability of the resulting polyplexes. They were complexed with non-integrating DNA vectors coding for reporter genes by simple admixing and assessed in vitro using liver-derived HuH-7 cells for their transfection efficiency and cytotoxicity. Using a rational screening cascade, a lead compound was selected (dCS-Suc-LPEI-14) displaying the best balance of biocompatibility, cytotoxicity, and transfection efficiency. Scale-up and in vivo evaluation in wild-type mice allowed for a direct comparison with a commercially available non-viral delivery vector (in vivo-jetPEI). Hepatic expression of the reporter gene luciferase resulted in liver-specific bioluminescence, upon intrabiliary infusion of the chitosan-based polyplexes, which exceeded the signal of the in vivo jetPEI reference formulation by a factor of 10. We conclude that the novel chitosan-derivative dCS-Suc-LPEI-14 shows promise and potential as an efficient polymeric conjugate for non-viral in vivo gene therapy. 相似文献
2.
The porosity of -alumina-based materials is an important parameter affecting the extent of fluorination (aerogels > commercial -Al2O3 > xerogels) and, consequently, also the textural, acidic and catalytic properties of the final fluorinated materials. Only the highly fiuorinated aluminas having strong Lewis acidic sites catalyse the isomerisation of CHF2CHF2 to CF3CH2F. 相似文献
3.
Ivana Tomaz Luna Maslov Domagoj Stupić Darko Preiner Danijela Ašperger Jasminka Karoglan Kontić 《分离科学与技术》2016,51(2):255-268
Grape skin contains large amounts of different flavonoids so it can be used for their recovery. Optimization of enzyme-assisted extraction of flavonoids was conducted using oenological enzyme preparations with respect to enzyme dosage, temperature, extraction time, pH, and enzyme preparation. Optimal conditions were obtained using enzyme preparation Lallzyme EX-V, at the temperature of 45°C, time of 3 h, pH 2.0, and enzyme dosage of 10.52 mg/g. The new optimized extraction method is less expensive, simple, accurate, and selective for the recovery of simple flavonoids. It is based on an environmentally-friendly extraction solvent which may provide a valuable alternative to conventional methods. 相似文献
4.
Tomaz Gregoric 《世界建筑导报》2019,(2)
正项目情况:邀请竞赛2008年,开工2009年,竣工2012年项目类型:(学生)公寓工作室、公共空间、就餐区、生活空间、储藏空间建设单位:Regie Immobiliere de la Ville de Paris建筑面积:场地1 981平方米,工作室大小35平方米,建筑物931平方米,总建筑面积8 500平方米,景观1 050平方米建设成本:175万欧元建筑位于巴黎19区ParcLaVilette边角位置的一块极为狭长的场地上,是由Reichen和Robert建筑师完成的城市开发项目。 相似文献
5.
Tomaz Kosmac David Maurice Thomas H. Courtney 《Journal of the American Ceramic Society》1993,76(9):2345-2352
The feasibility and kinetics of synthesizing various nickel sulfides by milling of elemental mixtures of Ni and S in a high-energy shaker mill have been investigated. The phases Ni3 S2 and the high-temperature polymorph of NiS are formed readily via such processing. In distinction, it requires prolonged milling to obtain Ni7 S6 ; NiS2 can only be obtained as a minor reaction product; and Ni3 S4 cannot be formed by milling for the conditions of this study. Structural evolution during synthesis and the kinetics of Ni3 S2 formation are investigated in depth. S coats the Ni particles and sulfide formation takes place at the interface of the elements after a certain degree of microstructural refinement due to the plastic deformation accompanying milling. Ni3 S2 forms rapidly at this stage. However, a stasis in the reaction is then observed. This is associated with NiS formation and a slight decrease in the amount of Ni3 S2 . The stasis is of approximately 5-min duration and is followed by a recurrence in the formation of Ni3 S2 and a disappearance of the NiS phase. The kinetics can be mimicked through a model of the mechanical alloying process. The model is able to predict the time dependence of the initial and later stages of Ni3 S2 formation and the effect of other parameters, such as mill atmosphere and use of premilled powder, on the reaction kinetics. The microstructures found in the intermediate to later stages of milling are similar to those associated with self-sustaining reactions. 相似文献
6.
3-D/2-D registration of CT and MR to X-ray images 总被引:6,自引:0,他引:6
A crucial part of image-guided therapy is registration of preoperative and intraoperative images, by which the precise position and orientation of the patient's anatomy is determined in three dimensions. This paper presents a novel approach to register three-dimensional (3-D) computed tomography (CT) or magnetic resonance (MR) images to one or more two-dimensional (2-D) X-ray images. The registration is based solely on the information present in 2-D and 3-D images. It does not require fiducial markers, intraoperative X-ray image segmentation, or timely construction of digitally reconstructed radiographs. The originality of the approach is in using normals to bone surfaces, preoperatively defined in 3-D MR or CT data, and gradients of intraoperative X-ray images at locations defined by the X-ray source and 3-D surface points. The registration is concerned with finding the rigid transformation of a CT or MR volume, which provides the best match between surface normals and back projected gradients, considering their amplitudes and orientations. We have thoroughly validated our registration method by using MR, CT, and X-ray images of a cadaveric lumbar spine phantom for which "gold standard" registration was established by means of fiducial markers, and its accuracy assessed by target registration error. Volumes of interest, containing single vertebrae L1-L5, were registered to different pairs of X-ray images from different starting positions, chosen randomly and uniformly around the "gold standard" position. CT/X-ray (MR/ X-ray) registration, which is fast, was successful in more than 91% (82% except for L1) of trials if started from the "gold standard" translated or rotated for less than 6 mm or 17 degrees (3 mm or 8.6 degrees), respectively. Root-mean-square target registration errors were below 0.5 mm for the CT to X-ray registration and below 1.4 mm for MR to X-ray registration. 相似文献
7.
João P. Monteiro Fátima M. Santos Ana S. Rocha João P. Castro-de-Sousa João A. Queiroz Luis A. Passarinha Cândida T. Tomaz 《Proteomics. Clinical applications》2015,9(1-2):187-202
The vitreous humor (VH) is the largest component of the eye. It is a colorless, gelatinous, highly hydrated matrix that fills the posterior segment of the eye between the lens and retina in vertebrates. In VH, a diversity of proteins that can influence retinal physiology is present, including growth factors, hormones, proteins with transporter activity, and enzymes. More importantly, the protein composition of VH has been described as being altered in a number of disease states. Therefore, attempts aiming at establishing a map of VH proteins and detecting putative biomarkers for ocular illness or protein fluctuations with putative physiologic significance were conducted over the last two decades, using proteomic approaches. Proteomic strategies often involve gel-based or LC techniques as sample fractioning approaches, subsequently coupled with MS procedures. This set of studies resulted in the proteomic characterization of a range of ocular disease samples, with particular incidence on diabetic retinopathy. However, practical therapeutic applications arising from these studies are scarce at the moment. A pertinent example of therapeutic targets arising from VH proteomics has emerged concerning vasoproliferative factors present in the vitreous, which should be involved in neovascularization and subsequent fibrovascular proliferation of the retina, in ocular disease context. Therefore, this review attempts to sum up the information acquired from the proteomic approaches to ocular disease conducted in VH samples, highlighting its clinical potential for disclosing ocular disease mechanisms and engendering pharmacological therapeutic treatments. 相似文献
8.
Sebastjan Perko Ales Dakskobler Tomaz Kosmac 《Journal of the European Ceramic Society》2012,32(11):2633-2639
In this study the densification behavior of bimodal Y-TZP powder compacts consisting of nano/sub-micron-sized particles was studied and an explanation for their improved flexural strength while biscuit-sintered is provided. An in situ-heating TEM analysis revealed that up to 800 °C only the nanoparticles sinter in a bimodal mixture without any densification. By increasing the temperature to 900 °C the densification of the nanoparticles begins and partially densified nanoparticle clusters migrate into the contact area between the core particles. Consequently, the driving force for the sintering of the powder-blend compacts is reduced and this is reflected in a slower densification compared to that of the core material. At 1000 °C the sintered nanoparticle clusters begin to incorporate into the core material, resulting in a sharp increase in the strength due to the increased neck area. Biscuit-sintered powder-blend compacts reached a plateau of strength at 670 MPa, which was reached at a relative density of 70%. 相似文献
9.
Tobias Gawron-Deutsch Friederich Kupzog Alfred Einfalt 《e & i Elektrotechnik und Informationstechnik》2014,131(3):91-98
The growing share of volatile distributed generation in the electric power grids results in increased local network utilisation and challenges the conventional strategies for maintaining the system balance. While grid extensions and smart grid solutions are considered for network utilisation issues, new market mechanisms are in focus for the balancing challenge. It can be expected that distributed generators on one hand will be able to supply only part of their available power to the grid in peak times, and on the other hand will have (potentially changing) contracts with different trans-regional virtual power plants. Against this background it will be necessary to define rules dealing with expected network access conflicts. One strategy also followed in this work is to find market mechanisms that support economically efficient network extension. Such mechanisms will have to include local flexibility markets that allow for compensating network bottlenecks. This work proposes strategies and technical interfaces for coordinating market and grid operation by means of a “Flexibility Operator”. Its integration into a holistic smart grid concept is discussed. 相似文献
10.
Tetiana Borzda Christoph Gadermaier Natasa Vujicic Peter Topolovsek Milos Borovsak Tomaz Mertelj Daniele Viola Cristian Manzoni Eva A. A. Pogna Daniele Brida Maria Rosa Antognazza Francesco Scotognella Guglielmo Lanzani Giulio Cerullo Dragan Mihailovic 《Advanced functional materials》2015,25(22):3351-3358
The 2D semiconductor MoS2 in its mono‐ and few‐layer form is expected to have a significant exciton binding energy of several 100 meV, suggesting excitons as the primary photoexcited species. Nevertheless, even single layers show a strong photovoltaic effect and work as the active material in high sensitivity photodetectors, thus indicating efficient charge carrier photogeneration. Here, modulation spectroscopy in the sub‐ps and ms time scales is used to study the photoexcitation dynamics in few‐layer MoS2. The results suggest that the primary photoexcitations are excitons that efficiently dissociate into charges with a characteristic time of 700 fs. Based on these findings, simple suggestions for the design of efficient MoS2 photovoltaic and photodetector devices are made. 相似文献