Photochemical water splitting mediated by a C1 shuttle.

The possibility of performing photochemical water splitting in a two-stage system, separately releasing the H2 and O2 components, has been probed with two separate catalysts and in combination with a formaldehyde/formate shuttling redox couple. In the first stage, formaldehyde releases hydrogen vigorously in the presence of an Na4[Fe(CN)6]·10H2O catalyst, selectively affording the formate anion. In the second stage, the formate anion is hydro-genated back to formaldehyde by water and in the presence of a Bi2WO6 photocatalyst whilst releasing oxygen. Both stages operate at room temperature and under visible light irradiation. The two separate photocatalysts are compatible since water splitting can also be obtained in one-pot experiments with simultaneous H2/O2 evolution.

High pressure polymorphism of ß-TaON.

The high pressure behavior of TaON was studied using a combination of Raman scattering, synchrotron X-ray diffraction, and X-ray absorption spectroscopy in diamond anvil cells to 70 GPa at ambient temperature. A Birch-Murnaghan equation of state fit for baddeleyite structured ß-TaON indicates a high bulk modulus value Ko = 328 ± 4 GPa with K = 4.3. EXAFS analysis of the high pressure XAS data provides additional information on changes in the Ta-(O,N) and Ta-Ta distances. Changes in the X-ray diffraction patterns and Raman spectra indicate onset of a pressure induced phase transition near 33 GPa. Our analysis indicates that the new phase has an orthorhombic cotunnite-type structure but that the phase transition may not be complete even by 70 GPa. Similar sluggish transformation kinetics are observed for the isostructural ZrO2 phase. Analysis of compressibility data for the new cotunnite-type TaON phase indicate a very high bulk modulus Ko ∼ 370 GPa, close to the theoretically predicted value.

Polycyclic aromatic hydrocarbon reaction rates with peroxy-acid treatment: prediction of reactivity using local ionization potential.

Property-Encoded Surface Translator (PEST) descriptors were found to be correlated with the degradation rates of polycyclic aromatic hydrocarbons (PAHs) by the peroxy-acid process. Reaction rate constants (k) in hr(-1) for nine PAHs (acenaphthene, anthracene, benzo[a]pyrene, benzo[k]fluoranthene, fluoranthene, fluorene, naphthalene, phenanthrene, and pyrene) were determined by a peroxy-acid treatment method that utilized acetic acid, hydrogen peroxide, and a sulphuric acid catalyst to degrade the polyaromatic structures. Molecular properties of the selected nine PAHs were derived from structures optimized at B3LYP/6-31G(d) and HF/6-31G(d) levels of theory. Properties of adiabatic and vertical ionization potential (IP), highest occupied molecular orbitals (HOMO), HOMO/lowest unoccupied molecular orbital (LUMO) gap energies and HOMO/singly occupied molecular orbital (SOMO) gap energies were not correlated with rates of peroxy-acid reaction. PEST descriptors were calculated from B3LYP/6-31G(d) optimized structures and found to have significant levels of correlation with k. PIP Min described the minimum local IP on the surface of the molecule and was found to be related to k. PEST technology appears to be an accurate method in predicting reactivity and could prove to be a valuable asset in building treatment models and in remediation design for PAHs and other organic contaminants in the environment.

Use of the structured descriptive assessment to identify possible functions of challenging behaviour exhibited by adults with brain injury.

Behaviour modification procedures for challenging behaviour, based on principles of operant learning, benefit from an accurate appraisal of behavioural function. Numerous methods of direct and indirect functional assessment exist, which have relative strengths and weaknesses. In this study, structured descriptive assessments were used to identify the function of challenging behaviour. The application of this hybrid approach has been unexplored in the neurobehavioural literature. The structured descriptive assessments involved the systematic manipulation of antecedent variables (only) that were conducted by typical caregivers in the normal environment. Also, observational software was used to provide a high degree of analytical detail. The methodology was found to be effective in generating hypotheses of behavioural function and also efficient as a clinical research tool. Only just over 2.25 hours of assessment data were collected for each participant, on average, and yet functional relationships emerged in respect of all four participants. The aggression exhibited by two participants was deemed to serve a demand escape function and the challenging behaviours of the other two participants were attributed to an attention gaining function. Future studies should implement additional validity measures by corroborating findings with other (experimental) functional assessment techniques or by implementing treatment programmes based on its results.

Potential severity of aggressive behaviour after acquired brain injury: implications for recording.

Aggression is a consequence of acquired brain injury that may necessitate admission to neurobehavioural services. The 'Overt Aggression Scale - Modified for Neurorehabilitation' (OAS-MNR) is a valid, reliable means of capturing this. A criticism of observational rating scales is they do not reflect factors like intent to harm which results in recording anomalies. 'Attacks' has been proposed as a measure which achieves this within psychiatric settings. Principal goals of this study are to determine the usefulness of measuring similar concepts in neurobehavioural services and further validating both scales. A total of 1066 physical assaults were recorded in 6 weeks by 25 patients in an inpatient neurobehavioural programme using the OAS-MNR. Fifty incidents were also rated on Attacks. Convergent validity for using both measures in neurobehavioural services was found. Modifying OAS-MNR severity scores using one of two factors found to underlie Attacks produced an index that successfully discriminated incidents whose risk necessitated more intrusive intervention, which was not evident otherwise. Modifying scores that objectively reflect severity of physical assaults using measures of perceived intent should be a feature of observational recording scales such as the OAS-MNR. Ensuring robust inter-rater reliability will be essential in any development work.

Descriptive analysis of challenging behaviours shown by adults with acquired brain injury.

The neurorehabilitation field has been slow to embrace the practice of functional analysis prior to behavioural intervention. In this study we employed a descriptive functional assessment using continuous recording techniques facilitated by observational software. The aim was to explore whether challenging behaviours shown by nine ABI survivors were socially mediated. Analyses appraised the likelihood of challenging behaviours and environment events occurring concurrently and in sequence to test if a mutual social reinforcement hypothesis was applicable. All nine participants exhibited at least one behaviour that was socially reinforced. Across all participants, 88% of challenging behaviours showed a significant concurrent association with an environmental event. A demand escape function was identified for 13 behaviours and an attention maintained function in 13 cases. The complete behavioural repertoire of three participants served the same function. Five participants presented challenging behaviours with multiple functions. Only 8% of the concurrent analysis results were not explicitly corroborated by the sequential analysis. The findings indicate that challenging behaviours shown by these nine ABI survivors adhered to a social model of reinforcement and were functional. It is suggested that formal functional assessments within the field of neurorehabilitation may lead to better treatment outcomes.

Assessment of neurobehavioural disability: a review of existing measures and recommendations for a comprehensive assessment tool.

PRIMARY OBJECTIVE: Neurobehavioural disability (NBD) has a major impact on long-term psychosocial outcome: however, measures used to identify characteristics of NBD have not been fully evaluated. This review therefore discusses issues surrounding the concept and assessment of NBD following acquired brain injury (ABI) by examining the psychometric properties and other qualities of some of the most well known instruments used to assess NBD. It is the authors' intention to use this review to encourage researchers to develop new NBD measurement tools. MAIN OUTCOMES: The review highlights a number of concerns with existing measures, including; the absence of a clear theoretical framework, a failure to distinguish impairment, disability and handicap when measuring characteristics of NBD and issues surrounding reliability and validity. CONCLUSIONS: The authors propose, promote and encourage the development of further measures with improved reliability and validity to help ensure that the unique characteristics of NBD are captured more effectively.

Effective treatment of PAH contaminated Superfund site soil with the peroxy-acid process.

Peroxy-organic acids are formed by the chemical reaction between organic acids and hydrogen peroxide. The peroxy-acid process was applied to two Superfund site soils provided by the U.S. Environmental Protection Agency (EPA). Initial small-scale experiments applied ratios of 3:5:7 (v/v/v) or 3:3:9 (v/v/v) hydrogen peroxide:acetic acid:deionized (DI) water solution to 5g of Superfund site soil. The experiment using 3:5:7 (v/v/v) ratio resulted in an almost complete degradation of the 14 EPA regulated polycyclic aromatic hydrocarbons (PAHs) in Bedford LT soil during a 24-h reaction period, while the 3:3:9 (v/v/v) ratio resulted in no applicable degradation in Bedford LT lot 10 soil over the same reaction period. Specific Superfund site soil characteristics (e.g., pH, total organic carbon content and particle size distribution) were found to play an important role in the availability of the PAHs and the efficiency of the transformation during the peroxy-acid process. A scaled-up experiment followed treating 150g of Bedford LT lot 10 soil with and without mixing. The scaled-up processes applied a 3:3:9 (v/v/v) solution resulting in significant decrease in PAH contamination. These findings demonstrate the peroxy-acid process as a viable option for the treatment of PAH contaminated soils. Further work is necessary in order to elucidate the mechanisms of this process.

Challenges associated with the definition and assessment of inappropriate sexual behaviour amongst individuals with an acquired neurological impairment.

The subject of Inappropriate Sexual Behaviour (ISB) amongst clients with neurological impairment, specifically Acquired Brain Injury (ABI) and dementia, has received limited coverage to date within the literature. This paper discusses some of the problems encountered in the definition and quantification of ISB, in particular the absence of standardized measurement tools to record ISB within an inpatient setting. Whilst ISB is reported to be less prevalent than other behavioural sequelae of brain injury or dementia, it is suggested that its impact on patients and carers can be significant. Ill-defined terminology and the absence of relevant assessment tools add to the specific challenges of understanding and managing ISB within a care or rehabilitation setting. As a result, it is argued that the subjective attitudes of staff and the culture of an institution can dominate the approach taken to dealing with ISB for these client groups.

Reduction of chronic aggressive behaviour 10 years after brain injury.

This study demonstrates the successful management of aggressive behaviour with a client 10 years post-injury in a small, residential neurorehabilitation unit. The case presented is unusual for two main reasons. First, it proved possible to significantly modify previously chronic challenging behaviour many years after brain injury had been sustained. Secondly, the rehabilitation environment in which treatment was conducted did not comprise a highly specialized neurobehavioural service, Instead, staff were specifically trained regarding the administration of the treatment programme, which was based on principles derived from behaviour modification and applied neuropsychology. Specific interventions used included those of differential reinforcement and graduated increase of expectations. Recordings made over the course of 85 weeks demonstrate a significant decrease in the frequency and severity of aggression. Successful inhibition of challenging behaviour attained a level which facilitated transfer of the client to a non-institutionalized community home. Reasons underlying the success of the intervention, and the limitations inherent in attempting to manage aggression within neurorehabilitation environments will be discussed.

Reduction of severe aggressive behaviour in acquired brain injury: case studies illustrating clinical use of the OAS-MNR in the management of challenging behaviours.

Challenging behaviour, especially when this takes the form of aggression, may impede or prevent progress in neurorehabilitation. Despite its prevalence, the literature on management of aggression after brain injury is not extensive. It has been suggested that the 'Overt Aggression Scale-Modified for Neurorehabilitation' (OAS-MNR) could be used to help standardize future studies of aggressive behaviour. It was also suggested that this scale has sufficient properties to be useful in clinical work. In this paper, three case studies are described which attempt to illustrate the potential value of the OAS-MNR in neurorehabilitation. The use of the scale also provides evidence relating to the continued efficacy of the neurobehavioural model. In the first study, two cases are described in which reduction in aggression occurred through participation in individualized, needs-led holistic treatment programmes, which incorporated multiple interventions. These were based on neurobehavioural principles. In the second study, a further single case was presented which illustrated how the scale may be used to generate hypotheses regarding aggressive behaviour and to drive treatment. Causation and maintenance of aggression are discussed, especially with regard to cognitive impairment. Finally, practical points relating to the use of the OAS-MNR in clinical practice are reviewed.

The ecological validity of tests of executive function.

Ninety-two mixed etiology neurological patients and 216 control participants were assessed on a range of neuropsychological tests, including 10 neuropsychological measures of executive function derived from 6 different tests. People who knew the patients well (relatives or carers) completed a questionnaire about the patient's dysexecutive problems in everyday life, and this paper reports the extent to which the tests predicted the patients' everyday life problems. All of the tests were significantly predictive of at least some of the behavioral and cognitive deficits reported by patients' carers. However, factor analysis of the patients' dysexecutive symptoms suggested a fractionation of the dysexecutive syndrome, with neuropsychological tests loading differentially on 3 underlying cognitive factors (Inhibition, Intentionality, and Executive Memory), supporting the conclusions that different tests measure different cognitive processes, and that there may be limits to the fractionation of the executive system.

Use of a modified version of the Overt Aggression Scale in the measurement and assessment of aggressive behaviours following brain injury.

Aggressive behaviour creates a significant challenge in neurorehabilitation. Despite the success in using behaviour modification principles in the treatment of post-acute behavioural problems, psychopharmacological approaches to the management of aggression are more frequently reported. However, inconsistencies apparent in the literature hinder inter-study comparisons of treatment methods. These include severity of brain injury, neuropsychological status and rigour of experimental methodology used. Data about aggression is also inconsistently reported, especially with regard to classification and severity. Descriptions of how aggressive behaviour responded to pre-treatment is also generally absent. In this paper an observational rating scale is described in an attempt to address these inconsistencies. The Overt Aggression Scale has been modified by increasing the range of interventions to reflect current practice in neurorehabilitation, and by changing the language to make it suitable for UK users. A range of antecedents has also been added to make the scale useful in behavioural analysis. Preliminary results indicate inter-rater reliability is good, and it is a valid indicator of type and severity of aggression. Antecedents and interventions used in the management of aggressive behaviours in neurorehabilitation are also illustrated. Clinical use of the scale is also discussed.

The effectiveness of DRL in the management and treatment of severe behaviour disorders following brain injury.

Effective management of behaviour disorders following brain injury is essential if individuals are to achieve their rehabilitation potential. Best practice dictates that the intrusiveness of any operant approach used be minimal, remain in operation for the shortest time possible, and emphasize skill building. Ideally, treatment gains should maintain following its withdrawal. Reinforcement methods fulfil these criteria in that they are less intrusive, concerned with the establishment of pro-social behaviours, and encourage positive staff-patient interaction. While their efficacy has been well documented with other clinical populations, less is known regarding treatment of behaviour disorders in survivors of brain injury. Some existing studies are characterized by methodological weakness that limit understanding of any contribution made to observed improvement, and little is known regarding maintenance of treatment effects. In this paper the effectiveness of a variant of differential reinforcement, DRL, will be examined. Three cases will be presented which demonstrate increased behavioural control in response to the use of DRL. A strength of this paper is that the use of appropriate single-case design methodology, and follow-up data up to 18 months after treatment, permits more robust conclusions regarding the efficacy of DRL to be made. These are discussed, together with practical points regarding programme design.

Fear of incontinence and its effects on a community-based rehabilitation programme after severe brain injury: successful remediation of escape behaviour using behaviour modification.

The presence of continence problems following severe traumatic brain injury may be attributable to either organic or psychological factors. In the case of the latter this in turn may lead to the development of behaviours that result in avoidance of or escape from rehabilitation activities. In this paper, a single case study is described in which verbalized fear of incontinence prevented participation within a community rehabilitation programme. Assessment suggested that behaviours that led to escape from this programme were being maintained by negative reinforcement through reduction in anxiety associated with this activity. An intervention was implemented using graded exposure and differential reinforcement of incompatible behaviour. Treatment led to a significant reduction in escape behaviour; this had been maintained and consolidated further at 9-month follow-up. However, no change occurred to the client's prompted self-ratings of anxiety. Reasons for the discrepancy between improvement in behaviour but not self-report are discussed. The potential limitations of using cognitive-behavioural therapy with some survivors of severe traumatic brain injury are also discussed. Finally, comments are made concerning the applicability of the treatment techniques described here in the modification of escape and avoidance behaviours that may be acquired following brain injury.

The behavioral treatment of self-starvation and severe self-injury in a patient with borderline personality disorder.

The successful treatment by behavioral methods of self-starvation and self-injury in a 35-year-old psychiatric in-patient, with a diagnosis of borderline personality disorder, is described. An individualized program using positive and negative reinforcers to increase food and fluid intake was used, while a token economy therapeutic milieu with time out was used to decrease acts of self-injury and aggression. Progress in treatment generalized to a non-secure treatment environment, and was maintained at an 8-month follow-up. The study illustrates the differential response of active and passive self injurious behaviors to group-based and individual treatments, respectively.

The treatment of avoidance behaviour following severe brain injury by satiation through negative practice.

Brain-injured patients may frequently develop behaviour disorders in order to avoid participating in rehabilitation activities. In recent years, the use of behaviour modification techniques, particularly the use of positive reinforcement and time-out, has been increasingly reported in the literature as a means of remediating behaviour disturbance in this population. However, reward- or extinction-based programmes are generally not effective in the treatment of avoidance behaviours as they may be ineffective or, at worst, encourage further avoidance of rehabilitation activities. This paper, describes the use of satiation through negative practice in the successful treatment of a severely brain-injured patient whose behaviour, in the form of prolonged shouting, had previously not responded to the range of behavioural techniques used previously with this population. Two successive treatment programmes that were used in an attempt to satiate shouting are presented. Significant reductions in both the frequency and duration of shouting were found, enabling physical and functional gains to be made through successful participation in previously avoided rehabilitation activities. The validity of the use of this technique in the treatment of avoidance behaviour in brain-injured patients is discussed.

Hydrogen peroxide-mediated corneal endothelial damage. Induction by oxygen free radical.

Polymorphonuclear leukocytes and other inflammatory cells release superoxide anion and additional oxidant species following stimulation. Corneal endothelial cells were exposed to a flux of chemically generated superoxide anion (oxygen-free radical) produced by the combination of 1 mM hypoxanthine and 0.06 U/ml xanthine oxidase. Exposure of endothelial cells to the combination of hypoxanthine and xanthine oxidase resulted in anatomic disruption of the cells with interference in the function of endothelial water movement and resultant swelling of the corneal stroma. Catalase reduced the corneal swelling caused by exposure of endothelium to the oxygen-free radical generating system, whereas superoxide dismutase, ascorbic acid, D-mannitol, and ethanol did not prevent damage. The data suggest that hydrogen peroxide produced during the dismutation reaction of the superoxide anion is one of the toxic species, whereas the superoxide anion itself and the hydroxyl-free radical probably do not participate. The data suggest that corneal endothelial cells are susceptible to physiologic and anatomic damage induced by the products of reactive oxygen species, which, from previous studies, are known to be generated by inflammatory cells. The development of therapeutic modalities directed at the prevention of damage produced by hydrogen peroxide and other oxidant species may be of benefit in reducing corneal endothelial cell damage secondary to ocular inflammatory disease processes.

Pharmacological modification of rabbit corneal endothelial transport and permeability.

Either isolated normal or preswollen rabbit corneas were perfused across their endothelial surface with various drugs in the specular microscope. The deswelling rate of preswollen corneas was uninfluenced by calmodulin (1 and 10 micrograms/ml), phenylephrine (0.1 and 1 mM), DbcAMP (10(-4) M), theophylline (10(-3) and 10(-4) M), isoproterenol (2 x 10(-7) and 2 x 10(-6) M), or cyclic GMP (10(-4) and 10(-6) M). The swelling rate of normal thickness corneas was increased by furosemide (10(-5) and 10(-4) M) and thiocyanate (5 x 10(-2) and 5 x 10(-3) M) but not by SITS (10(-4) M), dipyridamole (5 x 10(-5) M) or NAP-taurine (10(-3) M). The results suggest that alteration of endothelial cyclic AMP or cyclic GMP levels has no influence on transendothelial fluid flow. Modulation of the metabolic processes underlying anion fluxes by furosemide and thiocyanate caused corneal swelling but none of the agents which affect passive anion exchange in other systems influenced transendothelial fluid movement. The furosemide and thiocyanate effects confirm that bicarbonate, or chloride, exchange may be important in part in the regulation of corneal dehydration by the endothelium.