956 resultados para L-lactic-co-glycolic acid (PLGA)
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New compounds with the general formulae [(NH3)(L)ZnFE(CO4] (L = ethylenediamine, N-methylethylenediamine, N,N′-dimethylethylenediamine and 1,3-propanediamine) were prepared and studied by vibrational spectroscopy. The data suggest that they may be formulated as monomers with a trigonal bipyramidal configuration around the iron atom. © 1984.
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9 Briefe und Beilage zwischen Alfred Sohn-Rethel und Max Horkheimer, 1936-1940 sowie Briefwechsel mit Joan M. Levi; 6 Briefe zwischen Joan M. Levi und Max Horkheimer, 1940; 1 Brief von Max Horkheimer an Assistac Westcent, 25.06.1937; 1 Brief von John MacMurray an Walter Adams, 19.05.1937; 1 Brief von Walter Adams an Theodor W. Adorno, 01.06.1937; 2 Briefe zwischen Charles Somlo & Co und Max Horkheimer, 06.06.1939, 12.09.139; 1 Brief von Martin Sommerfeld an Max Horkheimer, 29.05.1934; 3 Briefe von Josef Sondek an Max Horkheimer, 1937, 1942; 3 Briefe zwischen Elsa Sontheimer, Max Sontheimer und Max Horkheimer, Februar 1940, 07.03.1940; 1 Drucksache von der The Southard School an Max Horkheimer; 1 Brief von der Soziologischen Verlagsanstalt an Gertrud Janosi, 20.07.1931; 9 Briefe zwsichen Maurice J. Speiser und Max Horkheimer, 1936-1948; 2 Briefe zwischen de Spengler und Max Horkheimer, 30.11.1936, 27.01.1937; 5 Briefe zwischen Sterling D. Spero und Max Horkheimer, 1936-1937; 1 Lebenslauf von Herbert Spielberg; 1 Brief und 2 Beilagen von René A. Spitz an Max Horkheimer, 23.06.1938; 2 Briefe von Elsa Spriesterbach an Max Horkheimer, Juli 1949; 1 Brief von Ida M. Stadie an Max Horkheimer, 21.05.1937; 20 Rechnungen von A. L. Stamm & Co an Max Horkheimer, 1938-1939; 1 Brief von Rose Horkheimer an A. L. Stamm und Co, 28.09.1938; 1 Betriebsanleitung und 1 Auslieferugnsschein für Max Horkheimer vom Standard Air Conditioning, 03.03.1936; 1 Brief von Max Horkheimer an Standard Air Conditioning, 28.03.1936; 5 Briefe zwischen Taylor Starck und Max Horkheimer, 1943; 8 Briefe zwischen Hans Staudinger und Max Horkheimer, 1937, 1943; 1 Briefauszug und Beilage von Paul Stefan, 1940 sowie Briefwechsel mit Samuel R. Wachtell; 1 Brief von Samuel R. Wachtell an Gertrude Blitz, 23.10.1940; 3 Briefe zwischen Leo Löwenthal und Samuel R. Wachtell, September 1940, 23.10.1940; 1 Brief von Loe Löwenthal an Hermann Kesten, 01.10.1940; 7 Briefe und Beilage zwischen George Stefansky und Max Horkheimer, 1939-1940; 2 Briefe zwischen dem Refugee Section of the American Friends Service Committee und Max Horkheimer, 16.05.1940, 28.05.1940; 3 Briefe zwischen dem Institute of International Education und Max Horkheimer, 09.04.1940, April 1940; 1 Brief von Max Horkheimer an Friess, 01.03.1940; 1 Brief vom Institute of Sociology Malvern und Max Horkheimer, 31.01.1940; 3 Briefe zwischen Stein und Max Horkheimer, 30.11.1934, 1936, 1937; 7 Briefe von Estell A. Stein an Max Horkheimer, 1929, 1937; 1 Brief von Franz Stein an Max Horkheimer; 1 Brief von Friedrich Pollock an Gertrude R. Stein, 22.03.1939; 1 Brief von Leo Stein an Max Horkheimer, 25.07.1944; 1 Brief von Max Horkheimer an Emilia Steinacher, 20.07.1937; 4 Briefe zwischen Friedrich Steinfeld und Max Horkheimer, 1941, 1945; 1 Brief und Beilage von Eugene G. Steinhof an Max Horkheimer; 3 Briefe zwischen Ernst Steinitz und Max Horkheimer, 25.04.1938, April 1938; 2 Briefe zwischen Theodor Steltzer und Eric E. Warburg, 07.03.1948; 4 Brief zwischen Hermine Sterler und Max Horkheimer, 11.09.1939, 1939, 1941; 4 Briefe zwischen Alfred K. Stern und Max Horkheimer, 1938, 1940 sowie 1 Brief und 1 Beilage von Max Gottschalk; 1 Brief von Max Gottschalk an Max Horkheimer; 2 Briefe und 1 Beilage zwischen Erich Stern und Max Horkheimer, 26.02.1937, 17.03.1937; 2 Briefe und Beilage von Eugene I. Stern an Max Horkheimer, 1938; 2 Briefe zwischen Joseph M. Weidberg und Max Horkheimer, 15.07.1938, 29.07.1938; 1 Brief von Max Horkheimer an das Cooperative Bureau for Teachers, 03.02.1938; 12 Briefe zwischen Günther Stern und Max Horkheimer, 1936, 1938 sowie Briefwechsel mit John Guggenheim Memorial Foundation; 3 Briefe und 1 Beilage zwischen der John Simon Guggenheim Memorial Foundation und Max Horkheimer, 1937; 1 Brief vom Social Research Quarterly an Max Horkheimer, 03.01.1937; 3 Briefe zwischen Hugo Stern und Max Horkheimer, 06.12.1937, Dezember 1937;
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"Being a complete index to the residents of the city, also a classified business directory, gazetteer of Cass County."
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Mode of access: Internet.
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Mode of access: Internet.
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Mode of access: Internet.
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The presence Of D-amino-acid-containing polypeptides, defensin-like peptide (DLP)-2 and Ornithorhyncus venom C-type natriuretic peptide (OvCNP)b, in platypus venom suggested the existence of a mammalian D-amino-acid-residue isomerase(s) responsible for the modification of the all-L-amino acid precursors. We show here that this enzyme(s) is present in the venom gland extract and is responsible for the creation of DLP-2 from DLP-4 and OvCNPb from OvCNPa. The isomerisation reaction is freely reversible and under well defined laboratory conditions catalyses the interconversion of the DLPs to full equilibration. The isomerase is similar to 50-60 kDa and is inhibited by methanol and the peptidase inhibitor amastatin. This is the first known L-to-D-amino-acid-residue isomerase in a mammal. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.
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Poly(L-lactide-co-ε-caprolactone) 75:25% mol, P(LL-co-CL), was synthesized via bulk ring-opening polymerisation (ROP) using a novel tin(II)alkoxide initiator, [Sn(Oct)]2DEG, at 130oC for 48 hrs. The effectiveness of this initiator was compared withthe well-known conventional tin(II) octoateinitiator, Sn(Oct)2. The P(LL-co-CL) copolymersobtained were characterized using a combination of analytical technique including: nuclear magnetic resonance spectroscopy (NMR), differential scanning calorimetry (DSC), thermogravimetry (TG) and gel permeation chromatography (GPC). The P(LL-co-CL) was melt-spun into monofilament fibres of uniform diameter and smooth surface appearance. Modification of the matrix morphology was then built into the as-spun fibresvia a series of controlled off-line annealing and hot-drawing steps. © (2014) Trans Tech Publications, Switzerland.
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A poly(L-lactide-co-caprolactone) copolymer, P(LL-co-CL), of composition 75:25 mol% was synthesized via the bulk ring-opening copolymerization of L-lactide and ε-caprolactone using a novel bis[tin(II) monooctoate] diethylene glycol coordination-insertion initiator, OctSn-OCH2CH2OCH2CH2O-SnOct. The P(LL-co-CL) copolymer obtained was characterized by a combination of analytical techniques, namely nuclear magnetic resonance spectroscopy, gel permeation chromatography, dilute-solution viscometry, differential scanning calorimetry, and thermogravimetric analysis. For processing into a monofilament fiber, the copolymer was melt spun with minimal draw to give a largely amorphous and unoriented as-spun fiber. The fiber's oriented semicrystalline morphology, necessary to give the required balance of mechanical properties, was then developed via a sequence of controlled offline hot-drawing and annealing steps. Depending on the final draw ratio, the fibers obtained had tensile strengths in the region of 200–400 MPa.
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Poly(methylvinylether-co-maleic acid) (PMVE/MA) is commonly used as a component of pharmaceutical platforms, principally to enhance interactions with biological substrates (mucoadhesion). However, the limited knowledge on the rheological properties of this polymer and their relationships with mucoadhesion has negated the biomedical use of this polymer as a mono-component platform. This study presents a comprehensive study of the rheological properties of aqueous PMVE/MA platforms and defines their relationships with mucoadhesion using multiple regression analysis. Using dilute solution viscometry the intrinsic viscosities of un-neutralised PMVE/MA and PMVE/MA neutralised using NaOH or TEA were 22.32 ± 0.89 dL g-1, 274.80 ± 1.94 dL g-1 and 416.49 ± 2.21 dL g-1 illustrating greater polymer chain expansion following neutralisation using Triethylamine (TEA). PMVE/MA platforms exhibited shear-thinning properties. Increasing polymer concentration increased the consistencies, zero shear rate (ZSR) viscosities (determined from flow rheometry), storage and loss moduli, dynamic viscosities (defined using oscillatory analysis) and mucoadhesive properties, yet decreased the loss tangents of the neutralised polymer platforms. TEA neutralised systems possessed significantly and substantially greater consistencies, ZSR and dynamic viscosities, storage and loss moduli, mucoadhesion and lower loss tangents than their NaOH counterparts. Multiple regression analysis enabled identification of the dominant role of polymer viscoelasticity on mucoadhesion (r > 0.98). The mucoadhesive properties of PMVE/MA platforms were considerable and were greater than those of other platforms that have successfully been shown to enhance in vivo retention when applied to the oral cavity, indicating a positive role for PMVE/MA mono-component platforms for pharmaceutical and biomedical applications.
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Betalains are plant derived natural pigments that are presently gaining popularity for use as natural colorants in food industry. Although being betalains from red beetroot already used as food colorant (E- 162), these compounds are not as well studied as compared to other natural pigments such as anthocyanins, carotenoids or chlorophylls (I]. Since food additives are on the focus of public interest, it is becoming increasingly important to meet consumers' expectations for natural and healthy products. Hence, the search for new plant-derived colorants for the food industry is still necessary [2]. Betalains were originally called 'nitrogenous anthocyanins', which incorrectly implied structural similarities between the two pigment classes. There are two structurally different types of betalains: the yellow/orange betaxanthins which are the condensation products of betalamic acid and assorted amino compounds, and the red betacyanins which are formed by glycosylation and acylation of cyclo-DOPA [3]. Looking at the chemical structure of the pigment, the addition of an acid to the extraction solvent will increase the affinity of the pigment with the solvent. The aim of this study was to use Gomphrena globosa L. flowers, as an alternative plant source to obtain these pigments and to evaluate the best acid to be used within the extraction procedure. For that purpose three different acids (acetic, hydrochloric and phosphoric acids, all ofthem allowed by the food industry), adjusted at the same pH, were tested during a maceration extraction procedure. After the extraction a purification through C18 column was performed in order to obtain a more concentrate extract in betacyanins. The results were analysed by HPLC-PDA-MSIESI. The betacyanin profile allowed the identification of gomphrenin IIJIII and isogomphrenin IIIIII and the best results were achieved by performing the extraction procedure using hydrochloric acid (6.6 mg/g extract), while phosphoric acid only presented trace amounts of these compounds. When acetic acid was used, the pigment extracted was 6.8 times less (0.97 mg/g extract) when compared to HCI. In conclusion hydrochloric acid can be considered the most suitable acid to be applied in the extraction procedure of these pigments.
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The temporospatial controlled delivery of growth factors is crucial to trigger the desired healing mechanisms in target tissues. The uncontrolled release of growth factors has been demonstrated to cause severe side effects in its surrounding tissues. Thus, the first working hypothesis was to tune and optimize a newly developed multiscale delivery platform based on a nanostructured silicon particle core (pSi) and a poly (dl-lactide-co-glycolide) acid (PLGA) outer shell. In a murine subcutaneous model, the platform was demonstrated to be fully tunable for the temporal and spatial control release of the payload. Secondly, a multiscale approach was followed in a multicompartment collagen scaffold, to selectively integrate different sets of PLGA-pSi loaded with different reporter proteins. The spatial confinement of the microspheres allowed the release of the reporter proteins in each of the layers of the scaffold. Finally, the staged and zero-order release kinetics enabled the temporal biochemical patterning of the scaffold. The last step of this PhD project was to test if by fully embedding PLGA microspheres in a highly structured and fibrous collagen-based scaffold (camouflaging), it was possible to prevent their early detection and clearance by macrophages. It was further studied whether such a camouflaging strategy was efficient in reducing the production of key inflammatory molecules, while preserving the release kinetics of the payload of the PLGA microspheres. Results demonstrated that the camouflaging allowed for a 10-fold decrease in the number of PLGA microspheres internalized by macrophages, suggesting that the 3D scaffold operated by cloaking the PLGA microspheres. When the production of key inflammatory cytokines induced by the scaffold was assessed, macrophages' response to the PLGA microspheres-integrated scaffolds resulted in a response similar to that observed in the control (not functionalized scaffold) and the release kinetic of a reporter protein was preserved.
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The copolymer poly (L-co-D,L lactic acid), PLDLA, has gained prominence in the field of temporary prostheses due to the fact that their time of degradation is quite compatible with the requirement in the case of osseous fracture. In this work the in vivo degradation of devices from copolymer, as a system of plates and screws, used in fixation of the tibia of rabbits was studied. The devices were implanted in 15 adult rabbits, albinos, New Zealand race, and they were used as control devices of alloys of titanium (Ti-6Al-4V/ V grade). The use of copolymers, synthesized in the laboratory, was tested in the repair of fracture in rabbits'tibias, being assessed in the following times: 2 weeks, 2 months and 3 months. Morphological analysis of tissue surrounding the plate and screw system, for 2 weeks of implantation, showed the presence of osteoblasts, indicating a pre bone formation. After 2 months there was new bone formation in the region in contact with the polymer. This bone growth occurred simultaneously with the process of PLDLA degradation, invading the region where there was polymer and after 3 months there was an intense degradation of the copolymer and hence greater tissue invasion compared to 2 months which characterized bone formation in a region where the polymer degraded. The in vivo degradation study of the devices for PLDLA by means of histological evaluations during the period of consolidation of the fracture showed the efficiency of plate and screw system, and it was possible to check formation of bone tissue at the implantation site, without the presence of inflammatory reaction
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PURPOSE: To evaluate the potential delay of the retinal degeneration in rd1/rd1 mice using recombinant human glial cell line-derived neurotrophic factor (rhGDNF) encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) microspheres. METHODS: rhGDNF-loaded PLGA microspheres were prepared using a water in oil in water (w/o/w) emulsion solvent extraction-evaporation process. In vitro, the rhGDNF release profile was assessed using radiolabeled factor. In vivo, rhGDNF microspheres, blank microspheres, or microspheres loaded with inactivated rhGDNF were injected into the vitreous of rd1/rd1 mice at postnatal day 11 (PN11). The extent of retinal degeneration was examined at PN28 using rhodopsin immunohistochemistry on whole flat-mount retinas, outer nuclear layer (ONL) cell counting on histology sections, and electroretinogram tracings. Immunohistochemical reactions for glial fibrillary acidic protein (GFAP), F4/80, and rhodopsin were performed on cryosections. RESULTS: Significant delay of rod photoreceptors degeneration was observed in mice receiving the rhGDNF-loaded microspheres compared to either untreated mice or to mice receiving blank or inactivated rhGDNF microspheres. The degeneration delay in the eyes receiving the rhGDNF microspheres was illustrated by the increased rhodopsin positive signals, the preservation of significantly higher number of cell nuclei within the ONL, and significant b-wave increase. A reduction of the subretinal glial proliferation was also observed in these treated eyes. No significant intraocular inflammatory reaction was observed after the intravitreous injection of the various microspheres. CONCLUSIONS: A single intravitreous injection of rhGDNF-loaded microspheres slows the retinal degeneration processes in rd1/rd1 mice. The use of injectable, biodegradable polymeric systems in the vitreous enables the efficient delivery of therapeutic proteins for the treatment of retinal diseases.