A Synthetic Lectin for β-Glucosyl Barwell, Nicholas P.; Crump, Matthew P.; Davis, Anthony P.
Angewandte Chemie,
09/2009, Letnik:
121, Številka:
41
Journal Article
Recenzirano
Geschmacksache: Affinität und Selektivität makrotricyclischer Kohlenhdratrezeptoren lassen sich verbessern, indem man Alkoxygruppen (im Bild grün) an den Molekülgerüsten anbringt. So zeigt der ...Propoxy‐substituierte Rezeptor eine starke Selektivität für die β‐Glucosylgruppe. Glucose wird sowohl in Wasser als auch in rekonstituiertem Blutplasma gebunden, was zur Überwachung von Blutzuckerspiegeln genutzt werden könnte.
Besser als das Original: Ein hybrides Nanopartikelsystem aus peptidbeschichteten CdS‐ und Pt‐Nanopartikeln wirkt als Enzymmimetikum in der photoaktivierten Reduktion von Nitrat. Im Vergleich zu ...Enzymen zeigt der Nanopartikelkatalysator erhöhte Aktivität, wird durch Licht aktiviert und kann bei erhöhten Temperaturen eingesetzt werden. Zudem entfällt die Verwendung von Elektronenmediatoren und exogenen Elektronendonoren.
Drei Homologe des FK506‐Bindeproteins (FKBP12, FKBP12.6 und FKBP13) konnten mithilfe eines neuartigen Selektionsprotokolls unter Verwendung von AP1497 (siehe Struktur), einem FK506‐Mimetikum, und ...einer T7‐cDNA‐Phagen‐Display‐Bibliothek gleichzeitig geklont werden. Des Weiteren wurde ein quantitativer Assay für die Bindung an den Phagen durchgeführt, um die Affinität der isolierten Proteine zu ermitteln.
Den Austausch zwischen Atomen fördern! Bei neutralem pH und Raumtemperatur sorgt ein von Cyclodextrin abgeleitetes Keton dafür, dass sich Wasserstoffperoxid und Benzylalkohole in seinem aktiven ...Zentrum treffen und dort bis zu 60 000‐mal schneller miteinander reagieren als außerhalb des Cyclodextrins.
Provider: - Institution: - Data provided by Europeana Collections- The subject of this PhD thesis is derived from current problems of bone tissue engineering, related to processes of ...osteointegration, implantation and resolution of the problems arising from the implantation site inflammation. The first part of the thesis examines problems of biocompatibility and osteointegration of materials used as implants in bone tissue engineering. Thus, the formation of bioactive coatings of calcium hydroxyapatite (CHA) on two potential types of implants, metal and ceramic, using biomimetic method, was investigated. This method is appropriate because it enables formation of CHA with similar structural and morphological properties of a natural bone. It is based on the use of the solution of similar ionic composition as human plasma (they are known as simulated body fluids- SBF) and the conditions of CHA nucleation are similar to the conditions found in biological systems. The metal surface (stainless steel) was previously activated by spraying with the thin silica film, with OH groups that act as active centers of heterogeneous nucleation of apatite. Ceramic substrate- porous CHA scaffold was treated in biomimetic medium in order to improve nanotopology of scaffold inner walls, optimal for growth and activation of bone tissue cells. Three different polymers (PLGA, cellulose and alginate) were used for the functionalization of the scaffold walls in order to achieve its additional nanodesigning and increase of its surface activity. SBF, as well as the SBF combined with fetal calf serum and Eagle’s minimal essential medium, were used as bioactive liquid medium, where biomimetic nucleation of apatite occurs. The analysis of the phases formed in the biomimetic medium, using X ray diffraction method, confirmed that CHA was formed on the surface of all samples. Infrared spectroscopy showed that this is CHA of slightly shifted stoichiometry. Atomic force microscopy pointed the mechanism of nucleation, while scanning electron microscopy showed the morphology of nucleated phases. Mass measurements, with volume corrections made using the BET method, showed that the thickness of nucleated CHA film depends on the aging time of samples in SBF and the type of selected III IV biomimetic medium. Also, bio-acceptability of these materials was investigated in vitro and in vivo and very good results were obtained. The second part of the thesis focuses on resolving the problem of frequent inflammation that occurs during implantation, as well as the problem of local treatment of bone tissue diseases, using controlled drug delivery to the affected area. The goal is to develop such an implant material that will have required osteoinductive and osteoconductive properties and simultaneously release biologically active molecules at the interface of living tissue and the implant. Hydroxyapatite, as the one of the most common materials in bone tissue engineering, showed a great potential for this applications, and therefore it was chosen as a model system to study release kinetics of antibiotics that are used in treatments of bone tissue infections. Antibiotics were encapsulated in two different systems: in the polymer that was later incorporated in CHA scaffold and tablets obtained by compression of apatite powder. Besides apatite carriers, carrier for controlled drug delivery based on SiO2 was also created, using the spray drying method that allows obtaining the SiO2 particles of complex structural design with simultaneous drug immobilization on these particles. Afterwards, the release rate of antibiotics from these systems was measured. It was concluded that suitably designed porous carriers can sustain a drug long enough to control the process of local inflammation.- Predmet ove doktorske disertacije proističe iz aktuelne problematike inženjerstva koštanog tkiva, vezane za procese osteointegracije, implantiranja, kao i rešavanja problema inflamacije na mestima ugradnje implanata. Prvi deo disertacije posvećen je problemima vezanim za biokompatibilnost i osteointegraciju materijala koji se koriste kao implanti u inženjerstvu koštanog tkiva. S tim u vezi, ispitivano je formiranje bioaktivnih prevlaka kalcijum hidroksiapatita (HAP) na površini dve vrste potencijalnih implanata: metalnih i keramičkih, biomimičnom metodom. Ova metoda je pogodna jer omogućava dobijanje HAP-a sličnih strukturnih i morfoloških karakteristika kao prirodna kost. Zasnovana je na korišćenju rastvora sličnog jonskog sastava kao krvna plazma (poznatih kao simulirajući telesni fluidi-STF) pa su i uslovi nukleacije HAP-a slični uslovima nukleacije u biološkim sistemima. Površina metala (nerđajući čelik) prethodno je aktivirana nabacivanjem tankog sloja silicijum dioksida, sa ugrađenim OH grupama koje služe kao aktivni centri heterogene nukleacije apatita. Keramički supstrat- porozni HAP tretiran je u biomimičnom medijumu u cilju unapređenja nanotopologije unutratrašnjih zidova poroznog nosača koja je optimalna za rast i aktivaciju ćelija koštanog tkiva. Tri različita polimera (PLGA, celuloza i alginat) korišćena su za funkcionalizaciju zidova poroznog nosača radi njegovog dodatnog nanodizajniranja i povećanja njegove aktivnosti na površini. STF, kao i STF kombinovan sa serumom iz fetusa govečeta i Iglovim medijumom korišćeni su kao bioaktivni tečni medijumi u kojima se odvija biomimična nukleacija apatita. Analizom faza formiranih u biomimičnom medijumu, metodom difrakcije X-zraka, potvrđeno je da je HAP formiran na površini svih uzoraka. Infracrvenom spektroskopijom je utvrđeno da se radi o HAP-u blago promenjene stehiometrije. Mikroskopija atomskih sila ukazala je na mehanizam nukleacije, dok je skenirajuća elektronska mikroskopija ukazala na morfologiju nukleirane faze. Merenjem mase, uz korekcije zapremine urađene BET metodom, pokazano je da debljina filma nukleiranog I HAP-a zavisi od vremena boravka uzoraka u biomimičnom medijumu, kao i od vrste izabranog biomimičnog medijuma. Ispitana je i bioprihvatljivost ovih materijala u in vitro i in vivo uslovima, pri čemu su dobijeni veoma dobri rezultati. U drugom delu disertacije pažnja je usmerena ka iznalaženju rešenja za probleme učestalih inflamacija koje se javljaju prilikom ugradnje implanata, kao i za tretiranje oboljenja koštanog tkiva na lokalnom nivou, kontrolisanim otpuštanjem leka na obolelo mesto. Cilj je da se razvije takav implantni materijal koji će imati odgovarajuće osobine osteokondukcije i osteoindukcije i istovremeno oslobađati biološki aktivne molekule na međupovršinu živog tkiva i implanta. Veliki potencijal za takvu primenu pokazao je hidroksiapatit koji je jedan od najzastupljenijih materijala u inženjerstvu koštanog tkiva, zbog čega je i izabran kao model-sistem za ispitivanje kinetike otpuštanja antibiotika koji se koriste za lečenje infekcija koštanog tkiva. Antibiotici su inkapsulirani u dva različita sistema: u polimer koji je zatim deponovan na porozni apatitni nosač i u tablete dobijene kompresijom praškastog apatita. Pored apatitnih nosača, kreiran je i nosač za kontrolisano otpuštanje lekova na bazi SiO2, i to metodom sprej sušenja koja omogućava dobijanje SiO2 čestica složenog strukturnog dizajna uz istovremenu imobilizaciju leka na česticama. Zatim je praćena brzina otpuštanja antibiotika iz ovih sistema. Utvrđeno je da pogodno dizajnirani porozni nosači mogu zadržati lek dovoljno dugo vremena da bi se kontrolisao proces lokalne inflamacije.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- The importance of the colour generating scales in butterfly wing using Heliophorine copeprs as example- A lepkeszárny színeket ...előállító pikkelyeinek jelentősége- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Six small compactors with butterflies- Hat tárlódobozka lepkékkel- All metadata published by Europeana are available free of ...restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Die Oxidation von Silan mit Wasserstoffperoxid auf der Oberfläche filigran strukturierter biologischer Proben führt zur Bildung einer dünnen Silicatschicht. Nach dem Entfernen der Probe durch ...Calcinieren erhält man einen exakten, ausschließlich anorganischen Abdruck der Originalstruktur (hier die rasterelektronenmikroskopische Aufnahme der Silicatreplika eines Fliegenflügels). Damit ist die Konservierung empfindlicher archäologischer Proben in greifbare Nähe gerückt.
Članak donosi teorijski model za projektiranje mekih pneubotskih konstrukcija koje se mogu konstruirati i pokretati koristeći jedinični modularni volumenski element. Analizom konstrukcije mekih ...robota, pneumatski prilagodljivih i reagirajućih konstrukcija te umjetničkih instalacija, dobiven je set od četiriju osnovnih tipova tjelesnih nacrta kao apstraktnih izraza za projektiranje složenih modularnih pneubotskih konstrukcija u arhitekturi.
PDF