Search

Cognitive impairment is recognized as an important determinant of outcome in schizophrenia, but mental health services generally have little capacity to provide detailed neuropsychological assessments. Computerized testing would overcome this difficulty, provided that such testing was equivalent to testing by a clinician. Given that negative symptoms can include impaired motivation and attention, it is also important to know whether computerized testing is valid in people with more severe negative symptoms. Our study was designed to compare clinician-administered and computerized testing of two domains commonly impaired in schizophrenia, verbal memory and verbal fluency. We also evaluated the effect of negative symptoms on performance on computerized cognitive tests. Sixty-two participants with schizophrenia completed clinician-administered and computerized verbal memory and verbal fluency tasks. The Positive and Negative Syndrome Scale assessed negative symptom severity. The study found no difference in cognitive performance associated with the method of test administration. This finding held regardless of the severity of negative symptoms. We found that computerized cognitive testing was equivalent to clinician-delivered testing in assessing verbal memory and verbal fluency. This finding was not affected by the presence of negative symptoms. Our results support the use of computerized cognitive testing for people with schizophrenia.

The approach-withdrawal and valence-arousal models highlight that specific brain laterality profiles may distinguish depression and anxiety. However, studies remain to be conducted in multiple clinical populations that directly test the diagnostic specificity of these hypotheses. The current study compared electroencephalographic data under resting state, eyes closed conditions in patients with major depressive disorder (MDD) (N = 15) and post-traumatic stress disorder (PTSD) (N = 14) relative to healthy controls (N = 15) to examine the specificity of brain laterality in these disorders. Key findings included (1) reduced left-frontal activity in MDD, (2) a positive correlation between PTSD severity and right-frontal lateralisation, (3) greater activity in PTSD patients relative to MDD within the right-parietotemporal region, and (4) globally increased alpha power in MDD. Findings partially support the diagnostic applicability of the theoretical frameworks. Future studies may benefit from examining task-driven differences between groups. (c) 2010 Elsevier B.V. All rights reserved.

The prevalence and nature of post-traumatic stress disorder (PTSD) following mild traumatic brain injury (MTBI) is controversial because of the apparent paradox of suffering PTSD with impaired memory for the traumatic event. In this study, 1167 survivors of traumatic injury (MTBI: 459, No TBI: 708) were assessed for PTSD symptoms and post-traumatic amnesia during hospitalization, and were subsequently assessed for PTSD 3 months later (N = 920). At the follow-up assessment, 90 (9.4%) patients met criteria for PTSD (MTBI: 50, 11.8%; No-TBI: 40, 7.5%); MTBI patients were more likely to develop PTSD than no-TBI patients, after controlling for injury severity (adjusted odds ratio: 1.86; 95% confidence interval, 1.78–2.94). Longer post-traumatic amnesia was associated with less severe intrusive memories at the acute assessment. These findings indicate that PTSD may be more likely following MTBI, however, longer post-traumatic amnesia appears to be protective against selected re-experiencing symptoms. (JINS, 2009, 15, 862–867.)

The study aimed to identify brain functional indicators of working memory systems development between 6 and 18 years. Event-related potentials (ERPs) were recorded from 251 normally developing children to stimuli requiring the updating of working memory. Cluster analysis of event-related potential componentry divided the sample into three clusters (mean ages 9, 12 and 16 years), with ascending cluster membership independently associated with improved task performance. The clusters correspond to periods of grey matter loss and white matter increase observed in developing children, supporting the view that the clusters delineate three key qualitative stages in advancing cognitive capability during the maturation of higher brain systems function. This outcome identifies a biomarker with the potential for assessing abnormalities in the rate of brain development.

Designer drugs are synthetic structural analogues/congeners of controlled substances with slightly modified chemical structures intended to mimic the pharmacological effects of known drugs of abuse so as to evade drug classification. Benzylpiperazine (BZP), a piperazine derivative, elevates synaptic dopamine and serotonin levels producing stimulatory and hallucinogenic effects, respectively, similar to the well-known drug of abuse, methylenedioxymethamphetamine (MDMA). Furthermore, BZP augments the release of norepinephrine by inhibiting presynaptic autoreceptors, therefore, BZP is a "messy drug" due to its multifaceted regulation of synaptic monoamine neurotransmitters. Initially, pharmaceutical companies used BZP as a therapeutic drug for the treatment of various disease states, but due to its contraindications and abuse potential it was withdrawn from the market. BZP imparts predominately sympathomimetic effects accompanied by serious cardiovascular implications. Addictive properties of BZP include behavioral sensitization, cross sensitization, conditioned place preference and repeated self-administration. Additional testing of piperazine derived drugs is needed due to a scarcity of toxicological data and widely abuse worldwide.

Early Life Stress (ELS) has been associated with a range of adverse outcomes in adults, including abnormalities in electrical brain activity [1], personality dimensions [40], increased vulnerability to substance abuse and depression [14]. The present study seeks to quantify these proposed effects in a large sample of non-clinical subjects. Data for the study was obtained from The Brain Resource International Database (six laboratories: two in USA, two in Europe, two in Australia). This study analyzed scalp electrophysiological data (EEG eyes open, closed and target auditory oddball data) and personality (NEO-FFI), history of addictive substance use and ELS) data that was acquired from 740 healthy volunteers. The ELS measures were collected via a self-report measure and covered a broad range of events from childhood sexual and physical abuse, to first-hand experience of traumatizing accidents and sustained domestic conflict [41]. Analysis of covariance, controlling for age and gender, compared EEG data from subjects exposed to ELS with those who were unexposed. ELS was associated with significantly decreased power across the EEG spectrum. The between group differences were strongest in the eyes closed paradigm, where subjects who experienced ELS showed significantly reduced beta (F1,405=12.37, p=.000), theta (F1,405=20.48, p=.000), alpha (F1,405=9.65, p=.002) and delta power (F1,450=36.22, p=.000). ELS exposed subjects also showed a significantly higher alpha peak frequency (F1,405=6.39, p=.012) in the eyes closed paradigm. Analysis of covariance on ERP components revealed that subjects who experienced ELS had significantly decreased N2 amplitude (F1,405=7.73, p=.006). Analyses of variance conducted on measures of personality revealed that subjects who experienced ELS had significantly higher levels of neuroticism (F1,264=13.39, p=.000) and openness (F1,264=17.11, p=.000), but lower levels of conscientiousness, than controls (F1,264=4.08, p=.044). The number of ELS events experienced was shown to be a significant predictor of scores on the DASS questionnaire [27], which rates subjects on symptoms of depression (F3,688=16.44, p=.000, R2=.07), anxiety (F3,688=14.32, p=.000, R2=.06) and stress (F3,688=20.02, p=.000, R2=.08). Each additional early life stressor was associated with an increase in these scores independent of age, gender and the type of stressor. Furthermore, the number of ELS experiences among smokers was also found to be a positive predictor of the nicotine dependency score (Faegstrom Test For Nicotine Dependence, [19]) (F3,104=10.99, p=.000, R2=.24), independent of age, gender and type of stressor. In conclusion, we highlight the impact of a history of ELS showed significant effects on brain function (EEG and ERP activity), personality dimensions and nicotine dependence.

This study is an exploratory investigation of the regional timing of cortical activity associated with verbal working memory function. ERP activity was obtained from a single subject using a 124-channel sensor array during a task requiring the monitoring of imageable words for occasional targets. Distributed cortical activity was estimated every 2.5 ms with high spatial resolution using real head, boundary element modelling of non-target activity. High-resolution structural MRI was used for segmentation of tissue boundaries and co-registration to the scalp electrode array. The inverse solution was constrained to the cortical surface. Cortical activity was observed in regions commonly associated with verbal working memory function. This included: the occipital pole (early visual processing); the superior temporal and inferior parietal gyrus bilaterally and the left angular gyrus (visual and phonological word processing); the dorsal lateral occipital gyrus (spatial processing); and aspects of the bilateral superior parietal lobe (imagery and episodic verbal memory). Activity was also observed in lateral and superior prefrontal regions associated with working memory control of sensorimotor processes. The pattern of cortical activity was relatively stable over time, with variations in the extent and amplitude of contributing local source activations. By contrast, the pattern of concomitant scalp topography varied considerably over time, reflecting the linear summation effects of volume conduction that often confound dipolar source modelling.

Progress of mechanical alloying (MA) during milling of W with Re, in a SPEX Mill was monitored by x-ray diffraction, scanning electron microscopy and transmission electron microscopy. XRD patterns showed continuous decrease in the intensity of Re peaks with increasing MA time. However the Re peaks continued to be present even after 18 ks of milling. 36 kiloseconds of milling showed complete dissolution of Re, as observed by the absence of Re peaks in association with W peak shift in accordance with the dissolution of Re in W. Chemical homogeneity and extensive reduction in particle size of the alloy could be established by microstructural and chemical analysis using SEM and TEM. Isothermal heat treatment of the mechanically alloyed sample at 1700 K for 4 hours did not show any decomposition of the alloy. A similar heat treatment of the blended elemental powder showed the formation of metastable phase formation, possibly at the boundary of dissimilar powder particles. After pressing and sintering ...

The stimulus properties of aminorex and analogues of 4-methylaminorex, namely (4S,5S)-4-methylaminorex, N-methyl-(4S,5S)-4-methylaminorex, and the regioisomeric (R)- and (S)-2-amino-4-phenyl-2-oxazoline (rexamino) were compared in rats trained to distinguish (S)-amphetamine (1 mg/kg) from saline. The first three compounds, aminorex, (4S,5S)-4-methylaminorex, and N-methyl-(4S,5S)-4-methylaminorex shared discriminative stimulus effects with amphetamine, although the stimulus properties for racemic aminorex were less than those of the other two compounds. The two regioisomers, (R)- and (S)-rexamino, produced only partial generalisation to the amphetamine.

Fe{sub 3}Al produced by reaction synthesis was found to have higher yield strength over a wide range of temperatures compared to material of similar composition produced by conventional hot extrusion of prealloyed powder. The increase in strength is attributed to the smaller grain size of the reaction synthesized material. Essentially equal strain rate sensitivity has been observed for the materials produced by the different methods, with a maximum strain rate sensitivity coefficient of about 0.3. Super plasticity is not observed in the reaction synthesized material despite the material having a fine, stable, grain size. This is attributed primarily to particle pinning of the grain boundaries, and suggests that superplastic deformation is not necessarily expected to be a general property of iron aluminides in which a fine grained microstructure is formed.

In response to a demanding reactor conversion schedule, construction of the Shielded Sample Preparation Area (SSPA) was initiated in 2010 to augment the existing capabilities of the Hot Fuel Examination Facility (HFEF). While HFEF is and will remain the workhorse for post irradiation sample preparation, there is currently a large backlog of Post-Irradiation Examination (PIE) experiments caused by numerous competing projects (this backlog is expected to continue for the foreseeable future). HFEF, in its present configuration also lacks the ability to prepare samples suitable for several of the tests that have been identified for the successful conclusion of the RERTR program; these samples require fine detail machining of irradiated fuel plates.

A laboratory scale atomizer has been built at the Idaho National Laboratory. This has proven useful for laboratory scale tests and has been used to fabricate fuel used in the RERTR miniplate experiments. This instrument evolved over time with various improvements being made ‘on the fly’ in a trial and error process.

Event-related potentials may offer more precision than behavioural measures for understanding the extent and timing of information processing difficulties that follow closed head injury (CHI). Behavioural tests consistently indicate a general reduction in cognitive function but lack adequate diagnostic or prognostic function. This study compares a group of seven CHI patients, in which time since injury varied between 1 and 5 years following injury, with 10 matched controls on a three-tone discrimination task. Abnormality in the processing of tones as early as 200 ms following their onset, as measured by the P2 and N2 components of the event-related potential, indicated a general difficulty with tone discrimination. This abnormality was obtained despite differing damage profiles over patients and is likely to be due to the diffuse aspects of damage normal in CHI. These results also indicate that functional deficits in CHI patients can extend up to 5 years or more. A correlation between P2/N2 amplitudes and time since injury, however, suggests that both these components normalize with the passage of time and offers the prospect of a sensitive, non-behavioural measure of recovery in cognitive processing.

Currently diagnosis and assessment of ADHD relies on clinical interview and subjective ratings. Standardized objective cognitive tests can provide additional information about ADHD and help distinguish symptom profiles. Objective: To assess the cognition of adolescent ADHD subtypes using a standardized cognitive test battery. Study Group: Seventy-two ADHD combined subtype, 58 ADHD predominantly inattentive subtype and 130 age- and sex-matched healthy controls. Methods: Cognitive differences between ADHD subtypes were examined according to 1. symptom dimensions (inattentive versus hyperactivity/ impulsivity scores) and 2. category (ADHDcom vs. ADHDin). We examined whether cognitive performance would discriminate symptom profiles (from each other and from healthy controls), and whether these profiles could predict test performance. All subjects completed the standardized and fully computerized IntegNeuro test battery using a touch-screen protocol. These tests span the domains of sensori-motor, attention, executive function, language and memory, and have robust construct validity compared to traditional paper-and-pencil tests. The results highlighted the consistency with which performance varied across symptom profiles, irrespective of categorical or dimensional definitions. ADHDcom was primarily distinguished from ADHDin by increased errors and response variability in response inhibition and (to a lesser extent) selective attention tasks. Inattentive symptoms were more likely to predict cognitive performance and there is an indication that despite the same criteria, these symptoms may be more severe in the ADHDcom subtype. Conclusions: These findings highlight the specificity of cognitive deficits, which differentiate ADHD subtypes in adolescence. This study provides consistent evidence that accuracy and response variability in an executive function (response inhibition) task may best distinguish the common ADHD subtypes. © Freund Publishing House Ltd.

NeuroMarker combines EEG and ERP measures with neurocognitive tests in a fully computerized and standardized testing system. It is designed for use across the lifespan and has a large normative database of over 1,000 subjects. This study was a preliminary evaluation of "NeuroMarker" in subjects spanning four decades. Twenty-one healthy subjects (12-57 years) were tested at baseline and four weeks later. From the "Neuromarker" battery, the authors analyzed EEG data (eyes open and closed) and ERPs elicited during auditory oddball (N100, P200, N200, P300) and working memory (P150, P300) tasks. Concomitant neuropsychological data, acquired using a touch-screen system, comprised measures of sensori-motor, attention, verbal, executive, and memory function. Test-retest data were examined using analyses of variance and correlational procedures (corrected for multiple comparisons), with parallel analyses of age. EEG data did not differ across sessions, and showed high test-retest reliability (.71-.95), particularly for theta and delta (>.85). ERP components also showed sound reliability, particularly for sites where components are maximal: fronto-central N100 (.76-.77), centro-parietal P300 (.78-.81) to oddball targets, N100 and P200 (.74-.86) to oddball non-targets, and P150 amplitude and latency (.84-.93) to working memory stimuli. Neuropsychological tests showed a similarly sound level of consistency (on average, .70), with the most consistent tests tapping simple motor function, estimated intelligence, switching of attention (Part 2), verbal interference response time and memory intrusions (.71-.89). Age and sex did not have a differential impact on reliability for EEG, ERP, or neuropsychology measures. These findings provide preliminary evidence that the "NeuroMarker" battery is reliable for test-retest assessments. The results suggest that the standardized approach has utility for providing sensitive clinical and treatment evaluations across age groups.

The current study aimed to investigate whether children and adolescents diagnosed with Attention Deficit/Hyperactivity Disorder Predominantly Inattentive (AD/HD-in; Child n = 24, Adolescent n = 33) and Combined (AD/HD-com; Child n = 30, Adolescent n = 42) subtypes were more distractible than controls (Child n = 54; Adolescents n = 75), by assessing event-related potential (ERP), performance and peripheral arousal measures. All AD/HD groups displayed smaller amplitudes and/or shorter latencies of the P3a ERP component — thought to reflect involuntary attention switching — following task-deviant novel stimuli (checkerboard patterns) embedded in a Working Memory (WM) task. The P3a results suggested that both AD/HD-in and AD/HD-com subtypes ineffectively evaluate deviant stimuli and are hence more "distractible". These abnormalities were most pronounced over the central areas. AD/HD groups did not display any abnormalities in averaged heart rate over the WM task, a measure of peripheral arousal. They did display abnormalities in performance measures from the task, but these were unrelated to P3a abnormalities. AD/HD groups also displayed a number of deficits on Switching of Attention and Verbal Memory tasks, however, the pattern of abnormality mostly reflected general cognitive deficits rather than resulting from distraction.

Clinical depression is one of the most common psychiatric disorders in adults, yet non-clinical depression in the community may go unnoticed, despite high prevalence rates and significant psychosocial impairment. The aim of the current study was to classify 1,226 individuals from a community sample on the basis of depression scores (using the Depression Anxiety Stress Scales, DASS) and to determine whether depression in a non-clinical sample differed significantly from healthy controls on a profile of multimodal measures. The data analyzed in this study included personality, emotional intelligence, cognition and psychophysiology. It was predicted that non-clinically depressed participants would differ from healthy controls on measures of personality (increased neuroticism; decreased extraversion), emotional intelligence (decreased), cognition (impairments in executive dysfunction and memory impairment), psychophysiology (increased resting-state, right-frontal activation; diminished skin conductance) after controlling for gender, age, handedness and years of education. Findings provide support for the majority of hypotheses, though no evidence was found for memory impairment or frontal hemispheric asymmetry. Longitudinal studies are needed to determine the extent to which of these findings will have utility for the prediction of depression onset and treatment response/non-response.

The effects of 4-bromo-2,5-dimethoxyphenethylamine (Nexus), 3,4-methylenedioxyamphetamine (MDA), 3,4-methylenedioxyphenyl-2-butanamine (BDB), and cathinone were studied in the newly hatched chicken and compared to the effects of d-amphetamine and three hallucinogens in the same species. Cathinone, a psychomotor stimulant in man (6), produced effects that were qualitatively similar to effects seen after administration of d-amphetamine (i.e., distress vocalization, wing extension, inability to stand, and loss of righting reflex). BDB, a compound with unknown activity in man, and two known hallucinogens, Nexus (5) and MDA (1), produced effects in the chicken that are common to both stimulants and hallucinogens in this species. For example, both MDA and BDB produced abnormal body posture that was identical to that reported after administration of hallucinogens such as lysergic acid diethylamide (LSD) and harmine (11). Nexus, on the other hand, produced rigid penguin-like posture, an effect seen in the chicken after administration of another hallucinogen, mescaline (12). BDB also produced bursting forward movements, an effect commonly observed after LSD and harmine. Our findings suggest that the young chicken can be used as an alternative, nonmammalian, model for predicting classification of new compounds.

Least square backpropagation (LSB) algorithm is employed to train a three-layer neural network for segmentation of magnetic resonance (MR) brain images. The simulation results demonstrate the use of LSB algorithm as a promising method for the segmentation of multi-modal medical images. The training time has been dramatically reduced comparing with that of BP network. The influence of the number of neurones in the hidden layer of the network is discussed in the paper.

An alternative, more cost-effective approach to cancellation and angle estimation in airborne radars is proposed. A set of preformed, phase-steered, product-pattern monopulse beams are used to form adapted sum ( Sigma ) and difference ( Delta ) beams that yield undistorted target monopulse ratio estimates while nulling both main-beam and sidelobe ECM (electronic countermeasures). The authors consider three approaches to optimal weight calculation. The first is a straightforward sample-matrix-inversion algorithm, which maximizes the signal-to-noise ratio in a prespecified look direction or, equivalently, minimizes the adapted beam residue subject to a unity-gain constraint in the prespecified look direction. The other two approaches to adaptive weight optimization are based on finding the eigenvector with the minimum eigenvalue for modified versions of R (the sample covariance matrix). Results of algorithm performance analysis are presented. The bandwidth effects of phase-steered antennas on the main beam canceller are also discussed. >

The paper deals with the problem of processing acoustic signals originating from multiple sources in a potentially noisy environment. Previous research in speech processing and cognitive modelling has tended to concentrate on single sources and relatively noise free signals. Separating out different signals from a multitude of sources is a significant part of human auditory processing. In speech processing research, the problem we are dealing with is known as the cocktail party syndrome. The processing of polyphonic music involves similar challenges, and auditory scene analysis (ASA) has been proposed as a means of separating out component signals and identifying their sources. In subliminal auditory processing, a speech signal which is masked from conscious awareness by a music signal provides an extreme form of the multiple source problem and permits exploration of the boundary between conscious and unconscious auditory processing. The research presented employs machine learning and associative models to characterize and track individual signals, and uses electroencephalographic (EEG) analysis to more precisely characterize human processing of multimodal signals.

The pharmacokinetics of HI-6 ((4-carboxamidopyridinium (1) methyl)-(2′-hydroxyiminomethyl-pyridinium (1′) methyl) ether dichloride) have been studied in rabbits receiving an intramuscular (50 μg kg−1) or intravenous (12·5 μg kg−1) dose. The plasma concentration-time profile for the intramuscular dose (n = 8) fits a one-compartment open model with first-order absorption and elimination. The absorption half-life was 2 min and maximum concentration (51 μg mL−1) was reached in 9 min. The pharmacokinetics for the intravenous dose (n = 8) was described by a two-compartment open model with first-order distribution and elimination. The apparent volume of distribution was 0·1 Lkg−1. Half-lives of distribution and elimination were 5 and 38 min, respectively. The results indicate HI-6 is rapidly absorbed, distributed and eliminated in rabbits receiving an intramuscular dose.

The purpose of the present study was to evaluate the behavioral effects of 3,4-methylenedioxyphenyl-2-butanamine (BDB), N-methyl BDB (MBDB), and N,N-dimethyl BDB (MMBDB) in the newly hatched chicken. The primary amine, BDB, produced effects that are commonly seen in the chicken after administration of both hallucinogens and psychomotor stimulants (i.e., distress vocalization, tremor, and wing extension). It also produced abnormal body posture and bursting forward locomotion, effects elicited only by hallucinogens. Loss of righting reflex also occurred at the highest (16 mg/kg) dose of BDB, and this effect is typical of d-amphetamine but has not been reported for hallucinogens. The monomethylated derivative of BDB, MBDB, was less potent than BDB, and the N,N-dimethyl analogue of BDB, MMBDB, had no effect on behavior at the doses tested.

An index-middle finger (double) tapping task was used to examine hemispheric differences in the planning and execution of skilled finger movements. In two experiments, subjects responded to a simple cue presented tachistoscopically in the left or right visual field,by performing a predetermined number of double taps. (between one and eight inclusive), with either the left or right hand. Reaction times (RT) increased linearly as a function of increasing number of taps, when response sequences were controlled by the left hemisphere. In contrast, an inverse quadratic trend was obtained with right hemisphere control. When both hemispheres were involve in the stimulus—response sequence, the latency function incorporated elements of both trends, suggesting interaction between the hemispheres. The RT trends reflect differences in motor planning between the hemispheres. The conditions engaging only the right or left hemispheres did not differ in motor execution, as measured by tapping duration, variability or errors. However, when both hemispheres were involved there was evidence of interaction, which was evident as interference when the right visual field or left hemisphere was cued but the motor response was under the control of the right hemisphere (left hand). Overall, the results indicate that hand differencesin fine motor skill may be determined by hemispheric differences associated with motor preparation rather than response execution.

A high-performance liquid chromatographic (HPLC) assay was developed to determine HI-6 (1-(2-hydroxyiminomethyl-1-pyridinio-3-(4-carbamoyl-1-py ridiniol-2-oxapropane dichloride)) concentrations in small volumes of plasma. A 100-microL plasma sample added to 900 microL of distilled water was microfiltered. Filtrate (200 microL) was injected onto an HPLC instrument containing a 100-microL sample loop, a C18 column, and an ultraviolet (UV) wavelength detector. Limit of sensitivity for HI-6 was 2.5 micrograms/mL. Extraction of efficiency (n = 12) at 10 and 100 micrograms HI-6/mL plasma was 69.4 +/- 6.6% (SD) and 81.5 +/- 2.0% (SD), respectively. Protein-plasma binding of HI-6 did not occur. HI-6 was stable when frozen at -20 degrees C for up to 10 days (0.025 less than p less than 0.05). Correlation coefficients representing standard curve linearity ranged from 0.9986 to 0.9999 (n = 6). Within-day and between-day coefficients of variation (n = 6) for unknown samples ranged from 4.4 to 8.3% and 5.8 to 17.1%, respectively. Bias of unknown samples ranged from -10.5 to 5.7%. The method's sensitivity, accuracy, and precision indicate that it can be used to accurately measure HI-6 concentrations in 100 microL of plasma.

The breakdown of working memory function in post-traumatic stress disorder in relation to everyday, non-traumatic stimuli is well appreciated by clinicians. But persuasive, neurobiological indices ...

This study was conducted to determine whether or not the antiestrogen CI-628 would block testosterone-maintained fighting in castrated male mice. TO strain adult male mice were castrated and injected s.c. every day for 14 days with either (1) 75 μg testosterone or (2) 75 μg testosterone and 1 mg CI-628, and in addition 1 mg of CI-628 6 hr prior to each injection of antiestrogen and androgen. Vehicle-injected, castrated, and CI-628-injected animals were employed as controls. Testosterone-maintained intermale aggressive behavior was blocked by the antiestrogen CI-628. This study provides support for the hypothesis that testosterone exerts its effects on the central nervous elements involved in the control of aggressive behavior by its aromatization to estrogenic metabolites.

The subject of this paper is the flow between an upper reservoir, containing a liquid, and a lower reservoir, containing a gas, interconnected by parallel vertical tubes. The characteristics of the combined system are predicted from a knowledge of the behavior of flow in individual tubes. Numerous modes of possible operation are described analytically and demonstrated experimentally. The effects of system geometry, changes in gas supply characteristics, operating procedure and two-phase flow regimes on the transitions between modes and system stability are presented. Predictions are made for the limiting case of a large number of identical parallel channels.

The rapid expansion of solar technology will result in the introduction of new materials into large numbers of residential dwellings. While some of these materials have been evaluated toxicologically for industrial applications, their use in residential solar energy systems require that they be more closely scrutinized for human health hazards. Twenty-one commercial heat transfer fluids which included ethylene and propylene glycol, silicone oils, and various hydrocarbon oil formulations were evaluated for acute oral toxicity in the rat, dermal and ocular irritation in the rabbit, and mutagenic potential in the Salmonella mutagenicity (Ames) test (TA 1538, TA 98, TA 1538, TA 1537, TA 100). Oral, 24-hr LD50 values ranged from 1.9 g/kg for a polyalkylene glycol formulation to > 24 g/kg for most hydrocarbon and silicone oils and propylene glycol-based products. None of the fluids were more than mildly irritating to rabbit skin. One fluid produced reversible corneal damage and transient conjunctivitis was observed in most animals treated with hydrocarbon oil and ethylene glycol formulation. None of the fluids were mutagenic in the Ames test at concentrations ranging from 10 μg to 100 mg per milliliter. These results suggest that most of the fluids may be considered relatively safe for use in residential solar energy applications.

Considerable evidence supports the existence of modulatory interactions between cholecystokinin and dopamine in the striatum. In order to explore further the nature of such interactions, the anatomical localization of CCK receptors in rat striatum was investigated autoradiographically following selective lesions. Infusion of 6-hydroxydopamine into the medial forebrain bundle had no effect on striatal CCK receptor content. In contrast, destruction of striatal cell bodies with ibotenic acid or quinolinic acid markedly reduced the number of striatal [125I]CCK-8 binding sites. CCK receptor levels were restored to normal following transplantation of neonatal striatal tissue into rats previously treated with ibotenic acid. These results suggest that CCK receptors are located primarily on intrinsic striatal neurones and not on nigrostriatal afferent fibres.

Five standardbred geldings received intravenous clenbuterol hydrochloride and saline in a crossover experiment to evaluate the effects of clenbuterol on certain cardiorespiratory parameters during and after treadmill exercise. The exercise test consisted of four steps. Step 1 at a speed of 76 m per minute, step 2 at 129 m per minute, step 3 at 190 m per minute and step 4 at 236 m per minute. The duration of each step was two minutes, except step 4 which was four minutes. The treadmill was set at a grade of 19 per cent. Before exercise, 30 minutes after clenbuterol or saline administration, arterial and mixed venous blood gases, mean arterial pressure, mean pulmonary artery pressure, telemetric electrocardiogram and respiratory rate were measured. The measurements were repeated immediately before completion of step 2, step 4 and after one minute, 10 minutes and 30 minutes of recovery from exercise. After clenbuterol administration there was a transient fall in mean arterial pressure, which had returned to control values by 90 seconds. There was no change in mean pulmonary artery pressure. During exercise the heart rate was significantly higher at the end of steps 1 and 4 and after 10 minutes recovery when horses given clenbuterol were compared with those given saline. No adverse effects on the electrocardiogram were demonstrated. Effects of clenbuterol on blood gases included an increase in PaO2 and decrease in PaC02 one minute after exercise, when compared to saline. It was concluded from the parameters examined that there was no evidence that clenbuterol had any significant untoward effect on the circulatory system of exercising horses.

A physical model of a gas reservoir having a vertical fracture with fracture half-length xf = 0.0635 m was developed. The model is a right circular cylinder of latex concrete with the radius xe = 0.305 m so that the xe/xf ratio is 4.8. The producing well is located at the center of the fracture. Experimental drawdown and buildup data taken from this reservoir were analyzed using available theoretical developments from the literature. The effect of pressure on permeability (the Klinkenberg effect) was included in the analysis. Simplex optimization was used in conjunction with unified (drawdown plus buildup) super-positioning to give fracture half-lengths of 0.0631 and 0.0635 m from two sets of experimental data. Corresponding values for permeability for these two sets of data were 0.0605 × 10−18 and 0.0624 × 10−18 m2, respectively, at a Klinkenberg coefficient of 5900 kPa. The fracture half-length and permeability are shown to be highly correlated. Thus, the results have more uncertainty than would be found in determining parameters by similar methods of analysis for an unfractured system. Bearing this in mind, the agreement between the known fracture half-length and values determined from the analysis of experimental data is excellent. Thus, we have demonstrated the utility of unified analysis as well as the ability to create an artificial fracture. Since the location of the model fracture relative to producing and observation wells is at the discretion of the designer, our model presents a unique opportunity to study various configurations which might be difficult to handle by mathematical modeling alone.