Photoionization of hot radicals: C2H5, n-C3H7, and i-C3H7.

The combination of ion-imaging and vacuum-ultraviolet (vuv) single-photon ionization is used to study the internal energy dependence of the relative photoionization yields of the C(2)H(5),n-C(3)H(7), and i-C(3)H(7) radicals following the 266 nm photodissociation of the corresponding alkyl iodides. The comparison of the ion images obtained by vuv photoionization of the radical with those obtained by two-photon-resonant, three-photon ionization of the complementary I (2)P(32) and I*(2)P(12) atoms allows the extraction of the internal energy dependence of the cross sections. Factors influencing the appearance of the ion images in the different detection channels are discussed, including the secondary fragmentation of the neutral radicals, Franck-Condon factors for the photoionization process, and the unimolecular fragmentation of the parent photoions.

Kinetic validation of the use of carboxydichlorofluorescein as a drug surrogate for MRP5-mediated transport.

Multidrug resistance protein-5 (MRP5, ABCC5) is a member of the ATP-binding cassette transporter superfamily that effluxes a broad range of natural and xenobiotic compounds such as cyclic GMP, antiviral compounds, and cancer chemotherapeutic agents including nucleoside-based drugs, antifolate agents and platinum compounds. In cellular assays, MRP5 transfectants are less fluorescent after incubation with 5-chloromethylfluorescein diacetate (CMFDA). The present study examines the uptake of a close fluorescent analog, carboxydichlorofluorescein (CDCF), and drug substrates into inside-out membrane vesicles prepared from MRP transfected cells.

Screening a library of potential prion therapeutics against cellular prion proteins and insights into their mode of biological activities by surface plasmon resonance.

The conversion of cellular prion protein (PrP(C)) to the protease resistant isoform (PrP(Sc)) is considered essential for the progression of transmissible spongiform encephalopathies (TSEs). A potential therapeutic strategy for preventing the accumulation of PrP(Sc) is to stabilize PrP(C) through the direct binding of a small molecule to make conversion less energetically favourable. Using surface plasmon resonance (SPR)-based technology we have developed a procedure, based on direct binding, for the screening of small molecules against PrP(C) immobilized on a sensor chip.

Increased heat shock protein 70 expression following toxicant-mediated cytotoxicity: a ubiquitous marker of toxicant exposure?

The up-regulation of heat shock protein (HSP) expression has been proposed as a general biomarker of cellular protection against various environmental stresses and chemicals. The present study investigated the possibility of using HSP70 up-regulation as a biomarker of toxicant exposure in vitro. Cells of a rat hepatoma cell line (FGC4) were exposed to concentrations of 1,3-dichloroacetone, duroquinone, diquat dibromide, menadione, hydrogen peroxide, cadmium chloride (CdCl2) and sodium (meta)arsenite (NaAsO2) that elicited 20-50% cytotoxicity over a 24-hour period, and HSP70 levels were measured by ELISA.

Isolation, characterization, gene modification, and nuclear reprogramming of porcine mesenchymal stem cells.

Bone marrow mesenchymal stem cells (MSCs) are adult pluripotent cells that are considered to be an important resource for human cell-based therapies. Understanding the clinical potential of MSCs may require their use in preclinical large-animal models, such as pigs. The objectives of the present study were 1) to establish porcine MSC (pMSC) cultures; 2) to optimize in vitro pMSC culture conditions, 3) to investigate whether pMSCs are amenable to genetic manipulation, and 4) to determine pMSC reprogramming potential using somatic cell nuclear transfer (SCNT).

Self-efficacy and psychosocial functioning in schizophrenia: a mediational analysis.

The construct of self-efficacy has been hypothesized to mediate the relationship between efforts at coping with psychiatric illness and functional outcome. This study examined whether self-efficacy mediated the relationships between psychosocial functioning and important predictors of functioning: premorbid functioning, negative symptoms, and cognitive functioning. Although self-efficacy was positively associated with psychosocial functioning, it did not mediate the relationships between functioning and the other established predictors.

Evaluation of clinical characteristics, diagnostic test results, and outcome in horses with internal infection caused by Corynebacterium pseudotuberculosis: 30 cases (1995-2003).

Objective: To determine clinical signs, results of diagnostic testing, and outcome in horses with internal Corynebacterium pseudotuberculosis infection.

Design: Retrospective study.

Animals: 30 horses.

'Active' filters for upgrading phosphorus removal from pond systems.

This paper investigates limestone and iron slag filters as an upgrade option for phosphorus removal from wastewater treatment ponds. A review of 'active' filter technology and the results from laboratory and field research using packed columns of the different media is presented. It is shown that both limestone and iron slag can remove phosphorus but highlights that different types of limestone give markedly different performance.

Knockdown of the Dnmt1s transcript using small interfering RNA in primary murine and bovine fibroblast cells.

RNA interference (RNAi) has rapidly developed into one of the most widely applied technologies in molecular and cellular research, and although young, is now an essential experimental tool. The versatility of RNAi, especially in mammalian species, lends to its potential applications in a wide array of fields. Without having to genetically manipulate the genome, the ability to selectively reduce the level of a specific transcript using small interfering RNA (siRNA) molecules has great appeal in studying reprogramming issues in somatic cell nuclear transfer (SCNT) embryos.

Photoionization of vibrationally hot CH3 and CF3.

Vibrationally hot CH(3) and CF(3) were produced by the 266 nm photodissociation of CH(3)I and CF(3)I, respectively, and probed by single-photon ionization at 118 nm. Comparison of the ion images of the CH(3) and CF(3) fragments with those of the complementary I atoms, and with previous measurements of the product branching fractions, allowed the determination of the relative photoion yields as a function of the vibrational energy of the molecular radical. Some general ideas about the internal-energy dependence of photoionization cross sections are also discussed.

The multidrug resistance protein 5 (ABCC5) confers resistance to 5-fluorouracil and transports its monophosphorylated metabolites.

5'-Fluorouracil (5-FU), used in the treatment of colon and breast cancers, is converted intracellularly to 5'-fluoro-2'-deoxyuridine (5-FUdR) by thymidine phosphorylase and is subsequently phosphorylated by thymidine kinase to 5'-fluoro-2'-dUMP (5-FdUMP). This active metabolite, along with the reduced folate cofactor, 5,10-methylenetetrahydrofolate, forms a stable inhibitory complex with thymidylate synthase that blocks cellular growth. The present study shows that the ATP-dependent multidrug resistance protein-5 (MRP5, ABCC5) confers resistance to 5-FU by transporting the monophosphate metabolites.

Speech recognition abilities in noise for children with severe-to-profound unilateral hearing impairment.

Objective: The purpose of this research was to compare the signal-to-noise ratio required for equal performance for children (aged 6-14 years) with normal hearing (N=17) versus those with severe-to-profound unilateral hearing impairment (N=20) who can be at a disadvantage, particularly when sounds are presented to the impaired ear. The listening environment is designed to approximate that which is encountered in a typical classroom.

Methods: All signals (Hearing in Noise Test-Children and Nonsense Syllable Test) were presented in the sound field from various azimuths with continuous noise presented from all quadrants.

Hearing sensitivity and bone mineral density in older adults: the Health, Aging and Body Composition Study.

Bone mineral density (BMD) may be associated with hearing loss in older adults. Demineralization of the cochlear capsule has been associated with hearing loss in those with Paget's disease of the bone and otosclerosis. Osteoporosis may also result in cochlear capsule demineralization.

Vibrational autoionization in polyatomic molecules.

The vibrationally autoionizing Rydberg states of small polyatomic molecules provide a fascinating laboratory in which to study fundamental nonadiabatic processes. In this review, recent results on the vibrational mode dependence of vibrational autoionization are discussed. In general, autoionization rates depend strongly on the character of the normal mode driving the process and on the electronic character of the Rydberg electron.

The LIM protein Ajuba influences p130Cas localization and Rac1 activity during cell migration.

Cell migration requires extension of lamellipodia that are stabilized by formation of adhesive complexes at the leading edge. Both processes are regulated by signaling proteins recruited to nascent adhesive sites that lead to activation of Rho GTPases. The Ajuba/Zyxin family of LIM proteins are components of cellular adhesive complexes.

Comparison of methods for the determination of K(L)aO2 for respirometric measurements.

The mass transfer coefficient for oxygen in water (K(L)aO2) is an important parameter for respirometric studies. But determination of K(L)aO2 in process conditions is not straightforward, In this paper, two distinct procedures for determining K(L)aO2 in process conditions are outlined and tested. The off-gas method relies on a gas mass balance over a bioreactor while the non-steady state methods rely on analysing DO recovery after perturbation.

Rate of nitrate production during a two-stage nitrification batch reaction.

The two steps of nitrification, namely the oxidation of ammonia to nitrite and nitrite to nitrate, often need to be considered separately in process studies. It has been assumed that these two reactions can be described by single Monod models. In this paper, the suitability of the single Monod model for describing nitrite oxidation to nitrate is discussed.

Photoionization and photodissociation dynamics of the B 1sigmau + and C 1Piu states of H2 and D2.

The photoionization and photodissociation dynamics of H(2) and D(2) in selected rovibrational levels of the B (1)Sigma(u) (+) and C (1)Pi(u) states have been investigated by velocity map ion imaging. The selected rotational levels of the B (1)Sigma(u) (+) and C (1)Pi(u) states are prepared by three-photon excitation from the ground state. The absorption of fourth photon results in photoionization to produce H(2)(+) X (2)Sigma(g)(+) or photodissociation to produce a ground-state H(1s) atom and an excited H atom with n >or= 2.

Modeling aerobic carbon oxidation and storage by integrating respirometric, titrimetric, and off-gas CO2 measurements.

A method for detailed investigation of aerobic carbon degradation processes by microorganisms is presented. The method relies on an integrated use of the respirometric, titrimetric, and off-gas CO(2) measurements. The oxygen uptake rate (OUR), hydrogen ion production rate (HPR), and the carbon dioxide transfer rate (CTR) resulting from the biological as well as physicochemical processes, coupled with a metabolic model characterizing both the growth and carbon storage processes, enables the comprehensive study of the carbon degradation processes.

Mode dependent vibrational autoionization of Rydberg states of NO2. II. Comparing the symmetric stretching and bending vibrations.

Triple-resonance excitation and high-resolution photoelectron spectroscopy are combined to characterize the mode selectivity of vibrational autoionization of the high Rydberg states of NO2. Photoelectron spectra and vibrational branching fractions are reported for autoionizing Rydberg states converging to the NO2+ X 1Sigmag +(110) state, that is, with one quantum in the symmetric stretch, nu1, and one quantum in the bending vibration, nu2. These results indicate that autoionization proceeds most efficiently through the loss of one quantum from the symmetric stretch rather than from the bending vibration.

Ion rotational distributions following vibrational autoionization of the Rydberg states of water.

Double-resonance laser excitation and high-resolution energy dispersive photoelectron spectroscopy were used to determine the ionic rotational-state distributions following vibrational autoionization of Rydberg states of water having principal quantum number n=8-10 and converging to the X (2)B(1) (1,0,0) state of H(2)O(+). Where possible, these states were identified by comparison with results of a calculation based on multichannel quantum defect theory. Symmetry and angular momentum constraints link the observed ionic rotational states to particular values of the orbital angular momentum of the Rydberg electron, l, and to the partial-wave composition of the ejected electron.

Hearing sensitivity and the risk of incident falls and fracture in older women: the study of osteoporotic fractures.

Purpose: To determine if age-related hearing loss may be related to bone health. Decreased vestibular function has been associated with hearing loss. We hypothesized that hearing loss would be related to an increased risk of falling and osteoporotic fracture in 6480 women aged 65 years or older enrolled in the Study of Osteoporotic Fractures.

Novel inhibitors of bacterial protein synthesis: structure-activity relationships for 1,8-naphthyridine derivatives incorporating position 3 and 4 variants.

Structure-activity relationships for a recently discovered novel ribosome inhibitor (NRI) class of antibacterials were investigated. Preliminary efforts to optimize protein synthesis inhibitory activity of the series through modification of positions 3 and 4 of the naphthyridone lead template resulted in the identification of several biochemically potent analogues. A lack of corresponding whole cell antibacterial activity is thought to be a consequence of poor cellular penetration as evidenced by the enhancement of activity observed for a lead analogue tested in the presence of a cell permeabilizing agent.