topology of polymers
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A combination of hard sphere and high internal phase emulsion templating gives a platform for synthesizing hierarchically porous polymers with a unique topology exhibiting interconnected spherical features on multiple levels. Polymeric spheres are fused by thermal sintering to create a 3D monolithic structure while an emulsion with a high proportion of internal phase and monomers in the continuous phase is added to the voids of the previously constructed monolith. Following polymerization of the emulsion and dissolution of the templating structure, a down-replicating topology is created with a primary level of pores as a result of fused spheres of the 3D monolithic structure, a secondary level of pores resulting from the emulsion's internal phase, and a tertiary level of interconnecting channels. Thiol-ene chemistry with divinyladipate and pentaerythritol tetrakis(3-mercaptopropionate) is used to demonstrate the preparation of a crosslinked polyester with overall porosity close to 90%. Due to multilevel porosity, such materials are interesting for applications in bone tissue engineering, possibly simulating the native sponge like bone structure. Their potential to promote ossteointegration is tested using human bone derived osteoblasts. Material-cell interactions are evaluated and they reveal growth and proliferation of osteoblasts both on surface and in the bulk of the scaffold.
- MeSH
- emulze chemie MeSH
- kosti a kostní tkáň fyziologie MeSH
- lidé MeSH
- modul pružnosti MeSH
- osteoblasty cytologie MeSH
- polymethylmethakrylát chemie MeSH
- poréznost MeSH
- teplota MeSH
- tkáňové inženýrství metody MeSH
- tkáňové podpůrné struktury chemie MeSH
- tvrdost MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Carbohydrates constitute a structurally and functionally diverse group of biological molecules and macromolecules. In cells they are involved in, e.g., energy storage, signaling, and cell-cell recognition. All of these phenomena take place in atomistic scales, thus atomistic simulation would be the method of choice to explore how carbohydrates function. However, the progress in the field is limited by the lack of appropriate tools for preparing carbohydrate structures and related topology files for the simulation models. Here we present tools that fill this gap. Applications where the tools discussed in this paper are particularly useful include, among others, the preparation of structures for glycolipids, nanocellulose, and glycans linked to glycoproteins. The molecular structures and simulation files generated by the tools are compatible with GROMACS.
External ionotropic gelation offers a unique possibility to entrap multivalent ions in a polymer structure. The aim of this experimental study was to prepare new drug-free sodium alginate (ALG) particles cross-linked by Cu2+ions and to investigate their technological parameters (particle size, sphericity, surface topology, swelling capacity, copper content, release of Cu2+ions, mucoadhesivity) and biological activity (cytotoxicity and efficiency against the most common vaginal pathogens-Herpes simplex, Escherichia coli, Candida albicans) with respect to potential vaginal administration. Beads prepared from NaALG dispersions (3 or 4%) were cross-linked by Cu2+ions (0.5 or 1.0 M CuCl2) using external ionotropic gelation. Prepared mucoadhesive beads with particle size over 1000 μm exhibited sufficient sphericity (all ˃0.89) and copper content (214.8-249.07 g/kg), which increased with concentration of polymer and hardening solution. Dissolution behaviour was characterized by extended burst effect, followed by 2 h of copper release. The efficiency of all samples against the most common vaginal pathogens was observed at cytotoxic Cu2+concentrations. Anti-HSV activity was demonstrated at a Cu2+concentration of 546 mg/L. Antibacterial activity of beads (expressed as minimum inhibition concentration, MIC) was influenced mainly by the rate of Cu2+release which was controlled by the extent of swelling capacity. Lower MIC values were found for E. coli in comparison with C. albicans. Sample ALG-3_1.0 exhibited the fastest copper release and was proved to be the most effective against both bacteria. This could be a result of its lower polymer concentration in combination with smaller particle size and thus larger surface area.
- MeSH
- algináty chemie farmakologie MeSH
- antibakteriální látky farmakologie MeSH
- gely chemie MeSH
- kationty MeSH
- kyselina glukuronová chemie farmakologie MeSH
- kyseliny hexuronové chemie farmakologie MeSH
- měď chemie farmakologie MeSH
- polymery chemie MeSH
- rozpustnost MeSH
- skot MeSH
- velikost částic MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
... 67 -- There Are Many Other Activated Carrier Molecules in Cells 68 -- The Synthesis of Biological Polymers ... ... Membrane-spanning a Helix -- Combinations of Start-Transfer and Stop-Transfer Signals -- Determine the Topology ... ... Fusion of Mitochondria Are Topologically Accesses -- Contain the Simplest Genetic Systems -- -e.e a Relaxed ... ... and Polymer-destabilizing Chemicals Actin-Binding Proteins Influence Filament Dynamics and Organization ... ... and Polymer-destabilizing Drugs A Protein Complex Containing y-Tubulin Nucleates Microtubules Microtubules ...
Sixth edition xxxiv, 1430 stran v různém stránkování : ilustrace (převážně barevné) ; 29 cm
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- molekulární biologie, molekulární medicína
- NLK Publikační typ
- učebnice vysokých škol
... in the Transfer of Specific Chemical Groups -- Biosynthesis Requires Reducing Power -- Biological Polymers ... ... Transfer Phospholipids from the ER to Mitochondria -- The Luminal Side of an Internal Organelle Is Topologically ... ... Polar -- Structures That Grow at Different Rates from Their -- Two Ends 574 -- Actin and Tubulin Polymers ...
xxxix, 1146 s. : il., tab. ; 28 cm
- MeSH
- biologie buňky MeSH
- molekulární biologie MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biologie
- cytologie, klinická cytologie
We present water-insoluble hyaluronan films crosslinked by trivalent iron developed as potential resorbable implants. The films were crosslinked by sorption of ferric salt into solid HA films in water/2-propanol bath. These heterogeneously crosslinked films (het-FeHA) remained tough and dimensionally stable when rehydrated in saline. In contrast, films prepared by drying the well-known homogeneous ferric hyaluronate gels (hom-FeHA) softened upon rehydration and expanded rapidly. Differences between hom-FeHA and het-FeHA result from polymer network topology (dominant inter- or intra-molecular crosslink, respectively). Moreover, Mössbauer spectroscopy of het-FeHA revealed diiron complexes, while iron in the hom-FeHA was present exclusively as γ-FeOOH nanoparticles or amorphous FeOOH. The biocompatibility tests of het-FeHA did not show any adverse effect and the sample disintegrated within one day when implanted in mice peritoneum. In conclusion, we developed implantable hyaluronan-based free-standing film with minimal swelling that can be resorbed quickly enough to avoid induction of foreign-body reaction.
- MeSH
- buňky 3T3 MeSH
- hydrogely chemie MeSH
- kyselina hyaluronová analogy a deriváty MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- nanočástice chemie MeSH
- peritoneum chirurgie MeSH
- reagencia zkříženě vázaná chemie MeSH
- vstřebatelné implantáty * MeSH
- železo chemie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
... Structure of Nucleic Acids 113 -- A Nucleic Acid Strand Is a Linear Polymer with -- End-to-End Directionality ... ... Some Secretory Proteins in Yeast 540 -- Insertion of Proteins into the ER Membrane 542 -- Several Topological ... ... Are Synthesized on the ER 543 -- Internal Stop-Transfer and Signal-Anchor Sequences -- Determine Topology ... ... Sequences 546 -- A Phospholipid Anchor Tethers Some Cell-Surface -- Proteins to the Membrane 547 -- The Topology ... ... Ancient, Abundant, and Highly Conserved 717 -- G-Actin Monomers Assemble into Long, Helical -- F-Actin Polymers ...
6th ed. xxxvii, 1150 s. : il., tab. ; 29 cm
- MeSH
- biologie buňky MeSH
- molekulární biologie MeSH
- Publikační typ
- monografie MeSH
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- biologie
- cytologie, klinická cytologie
... Demonstrated in Vitro 22 -- 2.2.2 RNA Molecules Can Act Äs Catalysts 23 -- 2.2.3 Amino Acids and Their Polymers ... ... Glycogen and Starch Are Mobilizable Stores of -- Glucose 302 -- 11.2.3 Cellulose, the Major Structural Polymer ... ... Can Wrap Around Itself to Form Supercoiled Structures 754 -- 27.3.1 The Linking Number of DNA, a Topological ...
5th ed. xvii, 974 s. : il., tab., grafy ; 32 cm
