Search results for " molecule"
showing 10 items of 1523 documents
Chemically Fueled Block Copolymer Self‐Assembly into Transient Nanoreactors**
2021
In chemically fueled supramolecular materials, molecular self-assembly is coupled to a fuel-driven chemical reaction cycle. The fuel-dependence makes the material dynamic and endows it with exciting properties like adaptivity and autonomy. In contrast to the large work on the self-assembly of small molecules, we herein designed a diblock copolymer, which self assembles into transient micelles when coupled to a fuel-driven chemical reaction cycle. Moreover, we used these transient block copolymer micelles to locally increase the concentration of hydrophobic reagents and thereby function as a transient nanoreactor.
Surface-Specific Spectroscopy of Water at a Potentiostatically Controlled Supported Graphene Monolayer
2019
Knowledge of the structure of interfacial water molecules at electrified solid materials is the first step toward a better understanding of important processes at such surfaces, in, e.g., electrochemistry, atmospheric chemistry, and membrane biophysics. As graphene is an interesting material with multiple potential applications such as in transistors or sensors, we specifically investigate the graphene–water interface. We use sum-frequency generation spectroscopy to investigate the pH- and potential-dependence of the interfacial water structure in contact with a chemical vapor deposited (CVD) grown graphene surface. Our results show that the SFG signal from the interfacial water molecules a…
Ambipolar Phosphine Derivatives to Attain True Blue OLEDs with 6.5% EQE
2016
A family of new branched phosphine derivatives {Ph2N-(C6H4)n-}3P → E (E = O 1-3, n = 1-3; E = S 4-6, n = 1-3; E = Se 7-9, n = 1-3; E = AuC6F5 4-6, n = 1-3), which are the donor-acceptor type molecules, exhibit efficient deep blue room temperature fluorescence (λem = 403-483 nm in CH2Cl2 solution, λem = 400-469 nm in the solid state). Fine tuning the emission characteristics can be achieved varying the length of aromatic oligophenylene bridge -(C6H4)n-. The pyramidal geometry of central R3P → E fragment on the one hand disrupts π-conjugation between the branches to preserve blue luminescence and high triplet energy, while on the other hand provides amorphous materials to prevent excimer form…
Endothelialization of a non-woven silk fibroin net for use in tissue engineering: growth and gene regulation of human endothelial cells
2004
Abstract We have previously shown that a biomaterial consisting of a non-woven fibroin net produced from silk (Bombyx mori) cocoons is an excellent scaffolding material for a wide variety of human cells of different tissue types. Endothelialization must take place for a biomaterial to be successful after implantation. Therefore, primary human endothelial cells and the human endothelial cell lines, HPMEC-ST1.6R and ISO-HAS-1, were examined for adherence and growth patterns on the fibroin nets by confocal laser scanning microscopy after vital staining of the cells and by electron microscopy. Endothelial cells adhered and spread along individual fibers of the nets and did not fill the gaps bet…
Software-supported image quantification of angiogenesis in an in vitro culture system: application to studies of biocompatibility
2002
Healing of soft tissue trauma and bone discontinuities following implantation involves acute inflammatory reactions and the formation of blood vessels (angiogenesis). During angiogenesis new capillary vessels arise from the existing vasculature. Endothelial cells (EC) are the major cell type involved in angiogenesis. Corrosion of orthopaedic metallic implant materials (e.g. CoCr alloys) can cause locally high concentrations of heavy metal ions in the peri-implant tissues. Some divalent metal ions (Co2+, Ni2+, Zn2+) lead to the activation of EC in vitro. Upon exposure to these ions. EC release cytokines and chemokines and increase the expression of cell surface adhesion molecules, which repr…
New generation super alloy candidates for medical applications: Corrosion behavior, cation release and biological evaluation
2014
Three super alloy candidates (X1 CrNiMoMnW 24-22-6-3-2 N, NiCr21 MoNbFe 8-3-5 AlTi, CoNiCr 35-20 Mo 10 BTi) for a prolonged contact with skin are evaluated in comparison with two reference austenitic stainless steels 316L and 904L. Several electrochemical parameters were measured and determined (E(oc), E(corr), i(corr), b(a), b(c), E(b), R(p), E(crev) and coulometric analysis) in order to compare the corrosion behavior. The cation release evaluation and in vitro biological characterization also were performed. In terms of corrosion, the results reveal that the 904L steels presented the best behavior followed by the super austenitic steel X1 CrNiMoMnW 24-22-6-3-2 N. For the other two super a…
The role of metal corrosion in inflammatory processes: induction of adhesion molecules by heavy metal ions
1994
Prosthetic devices undergo corrosion processes after implantation including the release of certain amounts of metal ions into the adjacent tissues. On reaching the bloodstream, a systemic influence of those ions may be envisaged. Cell adhesion molecules (CAMs) are recognized as an essential component of the mechanisms of endothelial damage. To study the influence of selected heavy metals on human umbilical vein endothelial cells (HUVEC) EIA methods were used to evaluate cellular expression of E-selectin, ICAM-1, VCAM-1 and GMP-140 under the influence of high (cytotoxic) very low (non-cytotoxic) concentrations of Zn, Ni, Co and Cr. The de novo synthesis of CAMs was studied with the help of m…
Torsional Bias as a Strategy To Tune Singlet–Triplet Gaps in Organic Diradicals
2018
Quinoidal compounds with proaromatic structures possess differing degrees of diradical character, where the open-shell diradical resonance form has restored aromaticity throughout the compound. Methods to tune the diradical character of these compounds have traditionally focused on altering the length and the molecular composition of the π-conjugated backbones. However, other molecular design strategies to tune the singlet–triplet gap of π-conjugated quinoidal molecules have not been extensively explored. We previously reported a strikingly small energy gap between the quinoidal and diradical states of a quinoidal small molecule containing methano[10]annulene (TMTQ) that was dictated in lar…
Doped TiO2 Nanomaterials and Applications
2008
This special issue brieflyreviews some trends and factors that have impacted heterogeneous photocatalysis with next generation TiO2 nanophotocatalysts that could absorband make use of both UV (290–400 nm) and visible (400–700 nm) sunlight to enhance process efficiencies, along with some issues of current debate in the fundamental understanding of the science that underpins the field. Preparative methods and some characteristics features of doped TiO2 as well as its environmental applications are presented and described. The next generation of doped TiO2 photocatalysts should enhance overall process photoefficiencies in many cases, since doped TiO2s absorb a greater quantity of solar radiati…
In Vitro–In Vivo Fluctuation Spectroscopies
2010
Fluorescence correlation spectroscopy (FCS) was first developed for biophysical studies in analogy with photon scattering correlation spectroscopy. Although it is mainly devoted to the study of freely diffusing particles, FCS is actually able to discern between different kinds of motions, such as diffusion, anomalous diffusion, or drift motions. The frontier application of FCS nowadays is in medical studies both within cells and on the cell membranes, and in the investigation of single molecules in solid matrices. In this field, FCS originated also image correlation spectroscopy methods. The whole field can be unified under the name of fluorescence fluctuation spectroscopy (FFS). We present…