Specifics about Specific Ion Adsorption from Heterodyne-Detected Second Harmonic Generation

Ion specific outcomes at aqueous interfaces remain among the most enigmatic phenomena in interfacial chemistry. Here, charged fused silica/water interfaces have been probed by homodyne- and heterodyne-detected (HD) second harmonic generation (SHG) spectroscopy at pH 7 and pH 5.8 and for concentrations of LiCl, NaCl, NaBr, NaI, KCl, RbCl, and CsCl ranging from 10 mc microM to several 100 mM. For ionic strengths around 0.1 mM to 1 mM, SHG intensities increase reversibly by up to 15% compared to the condition of zero added salt because of optical phase matching and electrical double layer. For ionic strengths above 1 mM, use of any combination of cations and anions produces decreases in SHG response by as much as 50%, trending with ion softness when compared to the condition of zero added salt. Gouy- Chapman model fits to homodyned SHG intensities for the alkali halides studied here show charge densities increase significantly with decreasing cation size. HD-SHG measurements indicate diffuse layer properties probed by the SHG process are invariant with ion identity, while Stern layer properties, as reported by chi(2), are subject to ion specificity for the ions surveyed in this work in the order of chi(2)RbCl = 1/2 chi(2)NaCl = 1/4 chi(2)NaI .Comment: Pre-edited version, 15 manuscript pages, 2 tables, 5 figures. Supporting Information available up request to the corresponding autho

Targeting RyR Activity Boosts Antisense Exon 44 and 45 Skipping in Human DMD Skeletal or Cardiac Muscle Culture Models.

Systemic delivery of antisense oligonucleotides (AO) for DMD exon skipping has proven effective for reframing DMD mRNA, rescuing dystrophin expression, and slowing disease progression in animal models. In humans with Duchenne muscular dystrophy treated with AOs, low levels of dystrophin have been induced, and modest slowing of disease progression has been observed, highlighting the need for improved efficiency of human skipping drugs. Here, we demonstrate that dantrolene and Rycals S107 and ARM210 potentiate AO-mediated exon skipping of exon 44 or exon 45 in patient-derived myotube cultures with appropriate mutations. Further, dantrolene is shown to boost AO-mediated exon skipping in patient-derived, induced cardiomyocyte cultures. Our findings further validate the ryanodine receptors (RyR) as the likely target responsible for exon skip boosting and demonstrate potential applicability beyond exon 51 skipping. These data provide preclinical support of dantrolene trial as an adjuvant to AO-mediated exon-skipping therapy in humans and identify a novel Rycal, ARM210, for development as a potential exon-skipping booster. Further, they highlight the value of mutation-specific DMD culture models for basic discovery, preclinical drug screening and translation of personalized genetic medicines

Survival of freeze-dried probiotics in soy protein powder

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on August 21, 2007)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2006.Dissertations, Academic -- University of Missouri--Columbia -- Food science.A series of well diffusion assays determined that Bifidobacterium longum B6 (B6) and Lactobacillus paracasei ATCC 25598 (LP) best inhibited pathogenic bacteria. These bacteria were freeze-dried in the presence of sucrose, trehalose and soymilk to determine the best conditions for survival. Cultures were anaerobically grown overnight and centrifuged. Cell pellets were resuspended in 10 mL of 4% sucrose + 18% soymilk (SS), 4% trehalose + 18% soymilk (TS) or 4% sucrose + 4% trehalose + 18% soymilk (STS). Suspensions were freeze dried and stored at room temperature in the dark. Statistical analysis found that at 24 days, treatments SS and STS were shown to be significantly better than TS (P [lesser than or equal to] 0.05). Bacteria were then freeze-dried with 4% sucrose + 4% trehalose + 18% soymilk (STS). Freeze dried bacteria were added to isolated soy protein powder. Samples were vacuum packaged and stored in the dark at room temperature or 4oC. The product was prepared for sampling on days 0, 15, 30, 45, 60, 75, and 90. Statistical analysis of percent reduction of bacterial counts (P [lesser than or equal to] 0.05) showed significant differences for bacteria, bacteria and treatment, and time. Actual counts and log reduction suggest that bacteria freeze-dried with the cryoprotectant solution STS and stored at 4oC best support bacterial growth in soy protein isolate powder

Toward Ultralight High Strength Structural Materials via Collapsed Carbon Nanotube Bonding

The growing commercial availability of carbon nanotube (CNT) macro-assemblies such as sheet and yarn is making their use in structural composite components increasingly feasible. However, the mechanical properties of these materials continue to trail those of state-of-the-art carbon fiber composites due to relatively weak inter-tube load transfer. Forming covalent links between adjacent CNTs promises to mitigate this problem, but it has proven difficult in practice to introduce them chemically within densified and aligned CNT materials due to their low permeability. To avoid this limitation, this work explores the combination of pulsed electrical current, temperature, and pressure to introduce inter-CNT bonds. Reactive molecular dynamics simulations identify the most probable locations, configurations, and conditions for inter-nanotube bonds to form. This process is shown to introduce covalent linkages within the CNT material that manifest as improved macroscale mechanical properties. The magnitude of this effect increases with increasing levels of prealignment of the CNT material, promising a new synthesis pathway to ultralight structural materials with specific strengths and stiffnesses exceeding 1 and 100 GPa/(g/cu.cm), respectively

Magnetic order in the frustrated Ising-like chain compound Sr3_3NiIrO6_6

We have studied the field and temperature dependence of the magnetization of single crystals of Sr3NiIrO6. These measurements evidence the presence of an easy axis of anisotropy and two anomalies in the magnetic susceptibility. Neutron powder diffraction realized on a polycrystalline sample reveals the emergence of magnetic reflections below 75 K with magnetic propagation vector k ~ (0, 0, 1), undetected in previous neutron studies [T.N. Nguyen and H.-C zur Loye, J. Solid State Chem., 117, 300 (1995)]. The nature of the magnetic ground state, and the presence of two anomalies common to this family of material, are discussed on the basis of the results obtained by neutron diffraction, magnetization measurements, and symmetry arguments