Anabolic Therapies

The striking clinical benefits of intermittent parathyroid hormone in osteoporosis have begun a new era of skeletal anabolic agents. Recombinant human parathyroid hormone (rhPTH) (1–34) is the first US Food and Drug Administration–approved anabolic therapy. Its use has been limited by the need for subcutaneous injection. Newer delivery systems include transdermal and oral preparations. Newer anabolic therapies include monoclonal antibody to sclerostin, a potent inhibitor of osteoblastogenesis; and use of bone morphogenetic proteins and parathyroid hormone–related protein PTHrP, a calcium-regulating hormone similar to PTH

Protein-Signaled Guided Bone Regeneration Using Titanium Mesh and Rh-BMP2 in Oral Surgery: A Case Report Involving Left Mandibular Reconstruction after Tumor Resection

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is an osteoinductive protein approved for use in oral and maxillofacial defect reconstruction. Growth factors act as mediators of cellular growth on morphogenesis and mythogenesis phases. Utilized as recombinant proteins, these growth factors need the presence of local target cells capable of obtaining the required results. This cell population may be present at the wound site or added to scaffolding material before implantation at the surgical site

Monitoring one-electron photo-oxidation of guanine in DNA crystals using ultrafast infrared spectroscopy

To understand the molecular origins of diseases caused by ultraviolet and visible light, and also to develop photodynamic therapy, it is important to resolve the mechanism of photoinduced DNA damage. Damage to DNA bound to a photosensitizer molecule frequently proceeds by one-electron photo-oxidation of guanine, but the precise dynamics of this process are sensitive to the location and the orientation of the photosensitizer, which are very difficult to define in solution. To overcome this, ultrafast time-resolved infrared (TRIR) spectroscopy was performed on photoexcited ruthenium polypyridyl–DNA crystals, the atomic structure of which was determined by X-ray crystallography. By combining the X-ray and TRIR data we are able to define both the geometry of the reaction site and the rates of individual steps in a reversible photoinduced electron-transfer process. This allows us to propose an individual guanine as the reaction site and, intriguingly, reveals that the dynamics in the crystal state are quite similar to those observed in the solvent medium

Interactions between metal ions and DNA

84 years elapsed between the announcements of the periodic table and that of the DNA double helix in 1953, and the two have been combined in many ways since then. In this chapter an outline of the fundamentals of DNA structure leads into a range of examples showing how the natural magnesium and potassium ions found in nature can be substituted in a diversity of applications. The dynamic structures found in nature have been studied in the more controlled but artificial environment of the DNA crystal using examples from sodium to platinum and also in a range of DNA-binding metal complexes. While NMR is an essential technique for studying nucleic acid structure and conformation, most of our knowledge of metal ion binding has come from X-ray crystallography. These days the structures studied, and therefore also the diversity of metal binding, go beyond the double helix to triplexes, hairpin loops, junctions and quadruplexes, and the chapter describes briefly how these pieces fit into the DNA jigsaw. In a final section, the roles of metal cations in the crystallisation of new DNA structures are discussed, along with an introduction to the versatility of the periodic table of absorption edges for nucleic acid structure determination

Reduction of the monomer quantities required for the preparation of radiation-grafted alkaline anion-exchange membranes

Alkaline anion-exchange membranes (AAEM) for alkaline polymer electrolyte fuel cells (APEFC) were successfully prepared using electron beam irradiated poly(ethylene-co-tetrafluoroethylene) precursor films grafted with vinylbenzyl chloride (VBC) monomer. The resulting chloromethyl groups were subsequently reacted with trimethylamine to form quaternary ammonium anion-exchange functional head-groups. The concentration of toxic and expensive VBC, that is required to achieve an optimal level of grafting, was reduced from 100%v/v (undiluted) to 20%v/v by dilution with propan-2-ol and the inclusion of a surfactant. Fuel cell tests using hydrogen and oxygen gave the same peak power densities (164 ± 3 mW cm- 2) for the AAEMs prepared with both 100%v/v VBC and 20%v/v VBC. This highlights the (desirable) lack of any detrimental effect on performance of the resulting APEFC with the reduction in grafting monomer concentration used for the synthesis of the component AAEM

Novel electrolyte membranes and non-Pt catalysts for low temperature fuel cells

Varying thicknesses of ethylene-co-tetrafluoroethylene (ETFE) Alkaline Anion Exchange Membranes (AAEMs) with quaternary ammonium functional groups were prepared using e-beam irradiation. The performances in H2/O2 single cellfuelcells were tested at 50 °C with the thinnest AAEM (S20) achieving the highest peak power density of 230 mW cm− 2. The ability to use non-Pt electrocatalysts for the oxygen reduction reaction (ORR) at the cathode was also investigated

Development of alkaline exchange ionomers for use in alkaline polymer electrolyte fuel cells

Alkaline polymer electrolyte fuel cells (APEFCs) using a quaternary ammonium functionalized ethylene-co-tetrafluoroethylene radiation grafted alkaline membrane were tested under fuel cell conditions using five anion exchange ionomers. The effect of ionomer type played a significant influence over the peak power densities achieved, ranging from 41 to 311 mW cm -2. © The Electrochemical Society

Investigations into the ex situ methanol, ethanol and ethylene glycol permeabilities of alkaline polymer electrolyte membranes

Alkaline anion-exchange membranes (AAEMs) are being developed for metal-cation-free solid alkaline fuel cells. Reduced solvent uptakes were observed after immersion in methanol, ethanol and ethylene glycol relative to a Nafion®-115 proton-exchange membrane (PEM); this translated directly into lower alcohol permeabilities. Alkaline polymer electrolytes showed lowered degrees of swelling (membrane thickness), when immersed in methanol and ethanol, relative to Nafion-115. The open circuit voltages, VOCV, of the corresponding direct alcohol fuel cells were superior to acid equivalents with membranes of identical fully hydrated thicknessess; this is indicative of a combination of reduced alcohol permeabilities and changed electrokinetics on PtRu anode catalysts at high pH. VOCV values for the AAEM-DAFCs were higher with ethanol than with methanol (consequent on lower permeability to ethanol), but were lower with ethylene glycol. Promisingly, and contrary to Nafion equivalents, peak power densities were not reduced when C2 alcohols (C-C bond containing) replaced methanol.</p