Synthesis and characterization of a metal-salen base pair for the assembly of programmed metal arrays inside the DNA double helix

Base pairing in natural oligonucleotides relies on hydrogen bonding and pi-stacking. Applying coordinative interactions between ligand-like nucleobases and metal cations is a new way of assembling artificial oligonucleotide duplexes. The incorporation of numerous metal-base pairs into oligonucleotides may lead to interesting compounds for nano-technological applications. In this thesis, the synthesis of the salen-metal base pair is described, which comprises preparation of a suitable protected salicylic aldehyde precursor and an organo-cuprate mediated C-glycosidation as the key step. An x-ray structure of the monomeric copper-salen base pair shows a very good geometrical match with natural Watson-Crick base pairs. Up to 10 consecutive salicylic aldehyde-nucleobases could be incorporated into DNA oligonucleotides by means of phosphoramidite chemistry. The synthesized double strands with one ligand show typical B-DNA CD-spectra and distinct melting characteristics. Addition of excess ethylenediamine and 1 eq of Mn2+ or Cu2+ increase the melting temp. by 28 °C and 42 °C, respectively. The complexation of these and other metals was examined by UV-, CD- and EPR-spectroscopy and high res. ESI mass spectrometry. It was possible to stack 10 manganese atoms inside the double helix and to prepare sequence specifically arrays of up to 5 copper ions plus 5 mercury ions inside one duplex

Haavasidoksen vaihto kirurgiseen haavaan : Opetusvideo keskivaiheen sairaanhoitajaopiskelijoille

Tuotokseen painottuvan opinnäytetyön tarkoituksena oli tuottaa Tampereen ammattikorkeakoulun kirurgisen hoitotyön keskivaiheen sairaanhoitajaopiskelijoille opetusvideo, aiheesta haavasidoksen vaihto kirurgiseen haavaan. Opinnäytetyön tehtävinä oli selvittää, millainen on kirurginen haava, millaista aseptiikkaa tarvitaan kirurgisen haavan hoidossa, miten haavasidos vaihdetaan kirurgisen haavaan ja millainen on hyvä opetusvideo. Työn tavoitteena oli tukea sairaanhoitajaopiskelijoiden oppimista liittyen alle 24 tuntia vanhan kirurgisen haavan hoitoon. Opetusvideolla havainnollistettiin haavan sidosvaihdon aseptiikkaa sekä valmistamaan opiskelijaa suunnittelemaan tulevaa haavanhoitoa. Opinnäytetyö toteutettiin toiminnallisena opinnäytetyönä, jonka tuotoksena oli opetusvideo ja kirjallinen raportti. Kirurgisella haavalla tarkoitetaan iholle tehtyä leikkaushaavaa. Kirurginen haava kuuluu pitää peiteltynä 24 tuntia leikkauksesta ja sitä käsitellään mahdollisimman vähän. Yleensä puhdas kirurginen haava paranee ongelmitta, mutta komplikaatioihin kuten verenvuotoon on osattava varautua. Haavan vuotaessa ja sidosten kastuessa haavasidos on vaihdettava pohjia myöten, vaikka haavan sulkemisesta olisi alle 24 tuntia. Tällöin haavasidoksen vaihto tulee tehdä steriilisti. Haavan paranemisen kannalta sairaanhoitajan ammattiosaaminen korostuu, jolloin on osattava kirurgisen haavan peittelyn perusteet. Aseptinen työskentely, haavasidoksen valinta ja tietotaito siitä, milloin haavasidoksen vaihto on tarpeellinen ehkäisevät mahdollisia komplikaatioita, kuten haavainfektioita. Opinnäytetyön tuotoksena valmistui opetusvideo kirjallisen raportin teoriatiedon pohjalta. Video toimii sairaanhoitajaopiskelijoille opetuksen tukena ja havainnollistaa konkreettisesti eri työvaiheita alle 24 tuntia vanhan kirurgisen haavan sidoksen vaihdossa. Opinnäytetyön kirjallista tuotosta ja opetusvideota voidaan hyödyntää kirurgisen hoitotyön opetuksessa. Alle 24 tuntia vanhan kirurgisen haavan sidosvaihdosta ei löydy selkeää ohjeistusta siitä, kuinka toimia, joten opinnäytetyö on hyvä lisämateriaali sairaanhoitajaopiskelijoille. Jatkotutkimusehdotuksena esitetään kvantitatiivista tutkimusta siitä, kuinka työelämässä kirurgisen haavan sidoksen vaihto tapahtuu ja kuinka eri työvaiheet toteutuvat.The aim of this study was to define the concept of a surgical wound, the methods of protection against infections in wound care and how to change the wound dressing for a surgical wound. Moreover, the aim was to produce a suitable educational video in addition to the theoretical part of the study.  The study had a functional approach with the written report and an educational video as a tangible output of the process. The aim of the report and the video was to support the education of nursing students in the care of an under 24-hour-old surgical wound. The educational video presents protection against infections during the change of a wound dressing. It also prepares the student to plan the upcoming wound care.  The surgical wound should be covered up and left untouched for 24 hours after the operation. The wound dressing should be changed thoroughly if the wound bleeds and the dressings get wet even though the operation has been performed less than 24 hours ago. In that case, the change of the dressings should be performed in a sterile manner. Written instructions on changing the surgical wound dressings being somewhat limited, this thesis provides important information about surgical wound care in this particular respect. There is a need for a further quantitative study about the various stages in changing the surgical wound dressings in hospital settings

Morphological control of heteroleptic cis- and trans-Pd2L2Lʹ2 cages

Control over the integrative self-sorting of metallo-supramolecular assemblies has recently generated significant interest as it opens up possibilities of introducing increased complexity and function into a single self-assembled architecture. Here, the relationship between the geometry of three ligand components and morphology of three self-sorted heteroleptic [Pd2L2Lʹ2]4+ cages is examined. Pd-mediated assembly of two bis-monodentate pyridyl ligands with native bite angles of 75° and 120° affords a cis-[Pd2L2Lʹ2]4+ cage while the same reaction with two ligands bearing bite angles of 75° and 60° forces an anti-conformation for latter ligand, leading to an unprecedented, self-penetrating structural motif; a trans-[Pd2(anti-L)2Lʹ2]4+ heteroleptic cage bearing a “doubly-bridged figure-eight” topology. Each heteroleptic assembly can be accessed through cage-to-cage conversion of their homoleptic precursors, and notably, morphological control of [Pd2L2Lʹ2] cages is achieved through selective ligand displacement transformations in a system of three ligands and at least six possible cage products

Mechanistic Interplay between Light Switching and Guest Binding in Photochromic [Pd 2 Dithienylethene 4 ] Coordination Cages

Photochromic [Pd2L4] coordination cages based on dithienylethene (DTE) ligands L allow triggering guest uptake and release by irradiation with light of different wavelengths. The process involves four consecutive electrocyclic reactions to convert all chromophores between their open and closed photoisomeric forms. So far, guest affinity of the fully switched species was elucidated, but mechanistic details concerning the intermediate steps remained elusive. Now, a new member of the DTE cage family allows unprecedented insight into the interplay between photoisomerization steps and guest location inside/outside the cavity. Therefore, the intrinsic chirality of the DTE backbones was used as reporter for monitoring the fate of a chiral guest. In its "open" photoisomeric form (o-L, [Pd2(o-L)4] = o-C), the C2-symmetric DTE chromophore quickly converts between energetically degenerate P and M helical conformations. After binding homochiral 1R-(-) or 1S-(+) camphor sulfonate (R-CSA or S-CSA), guest-to-host chirality transfer was observed via a circular dichroism (CD) signal for the cage-centered absorption. Irradiating the R/S-CSA@o-C host-guest complexes at 313 nm produced configurationally stable "closed" photoisomers, thus locking the induced chirality with an enantiomeric excess close to 25%. This value (corresponding to chiral induction for one out of four ligands), together with DOSY NMR, ion mobility mass spectrometry, and X-ray structure results, shows that closure of the first photoswitch is sufficient to expel the guest from the cavity

Thermodynamic Driving Forces of Guest Confinement in a Photoswitchable Cage

Photoswitchable cages that confine small guest molecules inside their cavities offer a way to control the binding/unbinding process through irradiation with light of different wavelengths. However, a detailed characterization of the structural and thermodynamic consequences of photoswitching is very challenging to obtain by experiment alone. Thus, all-atom molecular dynamics (MD) simulations were carried out to gain insight into the relationship between structure and binding affinity. Binding free energies of the B12F122- guest were obtained for all photochemically accessible forms of a photoswitchable dithienylethene (DTE) based coordination cage. The MD simulations show that successive photo-induced closure of the four individual DTE ligands that form the cage gradually decreases the binding affinity. Closure of the first ligand already significantly lowers the unbinding barrier and the binding free energy, and therefore favours guest unbinding both kinetically and thermodynamically. Analysis of the different enthalpy contributions to the free energy shows that binding is enthalpically unfavourable and thus an entropy-driven process, in agreement with experimental data. Dissecting the enthalpy into the contributions from electrostatic, van der Waals, and bonded interactions in the force field shows that the unfavourable binding enthalpy is due to the bonded interactions being more favourable in the dissociated state, suggesting the presence of structural strain in the bound complex. Thus, the simulations provide microscopic explanations for the experimental findings and open a possible route towards the targeted design of switchable nanocontainers with modified binding properties

Steuerung der ultraschnellen Öffnungs‐ und Schließungsdynamik eines photochromen Koordinationskäfigs durch Gastmoleküle

Photochemische Studien über supramolekulare Wirte, die kleine Gastmoleküle einkapseln können, konzentrieren sich zumeist auf drei Aspekte: Die Photoschaltung des Käfigs, um den Gast freizusetzen oder einzufangen, die Wirkung der Käfigumgebung auf den Gast und die lichtinduzierte Exzitonen- oder Ladungsübertragung innerhalb der Käfigstruktur. Hier nutzen wir ultraschnelle Spektroskopie, um zu untersuchen, wie der Gast die Photoschaltcharakteristik des Käfigs verändert. Zu diesem Zweck werden die Auswirkungen von drei unterschiedlichen Gastmolekülen auf die Ringöffnung oder den Ringschluss eines Dithienylethen (DTE)-Liganden in einem photoschaltbaren Koordinationskäfig auf DTE-Basis einander gegenübergestellt. Der Gast moduliert sowohl das Ergebnis als auch die Zeitskala der Photodynamik des Käfigs durch ein Zusammenspiel von struktureller Wechselwirkung, dem Schweratomeffekt und einer Verstärkung von Ladungstransferprozessen, die der Gast auf den photoangeregten Käfig ausübt. Der Ansatz könnte sich als nützlich erweisen, um die Anwendbarkeit von photoschaltbaren Nanocontainern und gewünschten Gastverbindungen aufeinander abzustimmen

Steering the Ultrafast Opening and Closure Dynamics of a Photochromic Coordination Cage by Guest Molecules

Photochemical studies on supramolecular hosts that can encapsulate small guest molecules commonly focus on three aspects: photoswitching the cage to release or trap the guest, the effect of the confining environment on the guest, and light-induced exciton or charge transfer within the cage structure. Here, we exploit ultrafast spectroscopy to address how the guest alters the photoswitching characteristics of the cage. For this, the impacts of three disparate guest compounds on ring-opening or ring-closure of a dithienylethene (DTE) ligand in a photoswitchable DTE-based coordination cage are juxtaposed. The guest modulates both outcome and timescale of the cage's photodynamics, by an interplay of structural strain, heavy-atom effect, and enhancement of charge-transfer processes exercised by the guest on the photo-excited cage. The approach might prove beneficial for attuning the applicability of photoswitchable nanocontainers and desired guest compounds

Rice field flora and vegetation in the provinces of Valencia and Tarragona

Twenty nine emergent and twenty floating or submerged taxa , were found in the rice fields in Valencia and Tarragona provinces. Eleven of the se taxa, all them emergent, are alien Of introduced ones. Echinochloa oryzoides and E. oryzicola are the most important in both areas, together with Cyperus difformis and Echinochloa hispidula in Valencia. The remaining thirty eight taxa belong to the native flora. There are predominantly the emergent Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli and Paspalum distichum; the floating Lemna minor and L. gibba; the submersed Potamogeton nodosus; Zannichellia palustris and Najas minor; and the macroscopical algae Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme, Spirogyra spp., Pithophora oedogania and Hydrodictyon reticulatum. The flora evolution during the last years is analyzed and the present weed communities are studied. The contribution of the different phytosociological classes to the rice field weed flora is presented.De los 49 táxones registrados (29 emergentes y 20 flotantes o sumergidos) 11 son exóticos introducidos, de los cuales los más importantes son Echinochloa oryzoides y E. oryzicolaen ambas zonas, además de Cyperus difformis y Echinochloa hispidula en Valencia, y el resto propios de la flora autóctona, predominando Scirpus maritimus, Alisma plantago-aquatica. Echinochloa crus-galli y Paspalum distichum como emergentes, Lemna minor y L. gibba como flotantes, Potamogeton nodosus, Zannichellia palustris y Najas minor como sumergidos y Chara vulgaris, Cladophora glomerata, Oedogonium capilliforme. Spirogyra spp., Pirhophora oedogonia e Hydrodictyon reticulatum como algas macroscópicas. Se analiza la evolución experimentada por la flora en los últimos años, además de estudiar las comunidades vegetales presentes y de indicar la importancia de las distintas clases fitosociológicas en su contribución a la flora arvense del cultivo