Guanine oxidation by electron transfer: one- versus two-electron oxidation mechanism

The degeneracy of the guanine radical cation, which is formed in DNA by oxidation of guanine by electron transfer, was studied by a detailed analysis of the oxidation products of guanine on oligonucleotide duplexes and by labeling experiments. It was shown that imidazolone, the major product of guanine oxidation, is formed through a one-electron oxidation process and incorporates one oxygen atom from O2. The formation of 8-oxo-7,8-dihydroguanine by a two-electron oxidation process was a minor pathway. The two-electron oxidation mechanism was also evidenced by the formation of a tris(hydroxymethyl)aminomethane adduct.     

A dynamical system approach to realtime obstacle avoidance

This paper presents a novel approach to real-time obstacle avoidance based on Dynamical Systems (DS) that ensures impenetrability of multiple convex shaped objects. The proposed method can be applied to perform obstacle avoidance in Cartesian and Joint spaces and using both autonomous and non-autonomous DS-based controllers. Obstacle avoidance proceeds by modulating the original dynamics of the controller. The modulation is parameterizable and allows to determine a safety margin and to increase the robot’s reactiveness in the face of uncertainty in the localization of the obstacle. The method is validated in simulation on different types of DS including locally and globally asymptotically stable DS, autonomous and non-autonomous DS, limit cycles, and unstable DS. Further, we verify it in several robot experiments on the 7 degrees of freedom Barrett WAM arm.     

Molecular basic data calculation for radiation transport in chromatin

Differential and integral electron impact ionisation cross sections were calculated using the binary-encounter-Bethe theoretical model for each core particle molecules: the four DNA bases, the backbone (sugar phosphate), and the 19 amino acids constituent of histone proteins. The binding energies and populations of molecular orbitals were computed using General Atomic Molecular Electronic Structure System. At present, there are neither experimental nor other theoretical results on amino acid electron impact ionisation cross sections. Regarding DNA bases and backbone, our results show good agreement with those published in journals.     

σ-Phase Formation in Super Austenitic Stainless Steel During Directional Solidification and Subsequent Phase Transformations

Metallurgical and Materials Transactions A - The solidification path and the σ-phase precipitation mechanism in the S31254 (UNS designation) steel are investigated thanks to Quenching during...     

Pre-clinical studies to validate the MITCH PCR™ Cup: a flexible and anatomically shaped acetabular component with novel bearing characteristics

A previous clinical study was undertaken to evaluate the safety and efficacy of an anatomically shaped, flexible acetabular cup. Clinical results achieved were satisfactory, although some deficiencies in the model were identified. Design changes to the original model have been implemented to improve both initial stability and long term biological fixation. This was achieved through modifications made to both the anchoring mechanism and by the application of an appropriate backing surface layer promoting bone on-growth. In addition, changes to the articulation couple have also been introduced to improve implant durability and bearing performance, utilising a carbon fibre reinforced polyetheretherketone—alumina couple. Simulated loading, in both models, was performed using Finite Element Analysis. Mechanical and tribological tests were also performed to ensure the robustness of the new optimised design. Bio-compatibility of the articulation couple was demonstrated using an animal model. Implantation of the device has been extensively tested and re-validated in vitro to achieve a favourable polar contact between cup and femoral head and establish a reproducible operative technique. This preliminary work is undertaken prior to commencing a post market surveillance study of the CE marked implant.     

Therapy for youths with anxiety disorders: A second randomized clincal trial.

Ninety-four children (aged 9-13 years) with anxiety disorders were randomly assigned to cognitive behavioral treatment or waiting-list control. Outcomes were evaluated using diagnostic status, child self-reports, parent and teacher reports, cognitive assessment and behavioral observation; maintenance was examined using l-year follow-up data. Analyses of dependent measures indicated significant improvements over time, with the majority indicating greater gains for those receiving treatment. Treatment gains returned cases to within nondeviant limits (i.e., normative comparisons) and were maintained at l-year follow-up. Client age and comorbid status did not moderate outcomes. A preliminary examination of treatment segments suggested that the enactive exposure (when it follows cognitive-educational training) was an active force in beneficial change. Discussion includes suggestions for future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A survey of Tactile Human–Robot Interactions

Robots come into physical contact with humans in both experimental and operational settings. Many potential factors motivate the detection of human contact, ranging from safe robot operation around humans, to robot behaviors that depend on human guidance. This article presents a review of current research within the field of Tactile Human–Robot Interactions (Tactile HRI), where physical contact from a human is detected by a robot during the execution or development of robot behaviors. Approaches are presented from two viewpoints: the types of physical interactions that occur between the human and robot, and the types of sensors used to detect these interactions. We contribute a structure for the categorization of Tactile HRI research within each viewpoint. Tactile sensing techniques are grouped into three categories, according to what covers the sensors: (i) a hard shell, (ii) a flexible substrate or (iii) no covering. Three categories of physical HRI likewise are identified, consisting of contact that (i) interferes with robot behavior execution, (ii) contributes to behavior execution and (iii) contributes to behavior development. We populate each category with the current literature, and furthermore identify the state-of-the-art within categories and promising areas for future research.     

Can bipolar disorder-specific neuropsychological impairments in children be identified?

This study examined neuropsychological deficits among children with bipolar disorder while attending to its comorbidity with attention-deficit/hyperactivity disorder (ADHD). Seventy-three unmedicated children (ages 6-17 years) with Diagnostic and Statistical Manual of Mental Disorders (4th ed.; American Psychiatric Association, 1994) bipolar disorder plus ADHD (BPD + ADHD) were compared with 102 unmedicated children with ADHD without bipolar disorder, and 120 children without bipolar disorder or ADHD. Ninety-four percent of participants were Caucasian, 58% were male, and 42% were female. On average participants were of middle to upper socioeconomic status. Participants were assessed with a comprehensive neuropsychological battery and measures of academic achievement, school failure, and special education placement. Participants with BPD + ADHD and with ADHD were impaired in interference control, verbal learning, and arithmetic achievement and had higher rates of special school services. Across all of the measures of neuropsychological functioning, the only difference observed between youths with BPD + ADHD and youths with ADHD was that youths with BPD + ADHD performed more poorly on one measure of processing speed. Thus, comorbidity with ADHD may account for many of the neuropsychological deficits observed in children with bipolar disorder. (PsycINFO Database Record (c) 2010 APA, all rights reserved)