Differences in depressive symptoms between traditional workers and shiftworkers

To investigate the effect of physical exertion on simple reaction time and continuous attention of sport participants, an experiment was conducted with 46 male university students and 12 male cyclists. The subjects were assigned to three experimental and two control groups. The subjects of the experimental groups were asked to perform, following a 5-min, period of warming up, a high intensity exercise protocol for 5 min., on a mechanically braked cycle ergometer (Group A) or a moderate intensity exercise protocol for 30 min, on the same cycle ergometer (Groups B and C). Shortly before and immediately after the physical exercise subjects of all groups were asked to perform a test of simple reaction time and continuous attention. The subjects of the control groups were asked to perform at rest both tests of the simple reaction time and the continuous attention twice, with a 10-min. and a 35-min. interval between the first and second attempts, respectively. The results did not support the notion that exercise of moderate or high intensity influences significantly the cognitive performance of aerobically trained or untrained subjects. The results are discussed in the light of the current research findings concerning exertion and human psychomotor performance.     

冷喷涂Zn-Ni复合涂层形貌及性能

利用冷喷涂制备了Zn-15%Ni复合涂层。应用扫描电镜(SEM)、EDS和XRD对涂层的形貌、成分、孔隙率进行分析,并研究了喷涂前对基体材料进行前处理和喷涂后对涂层进行后处理对涂层形貌、孔隙率和结合强度的影响。结果表明:制备出Zn-15%Ni的复合涂层,涂层主要是以Zn和Ni的单质相形式存在,无新的第二相形成,锌和镍均保持了原本的结构;复合涂层致密,孔隙率低、硬度高、结合力好;喷涂前对基体材料进行喷丸后再吹砂的前处理,有利于提高涂层的结合强度;喷涂后对涂层进行喷丸处理,可使涂层平整、致密。     

Cold water immersion modulates the reinforcing effects of nitrous oxide in healthy volunteers.

The purpose of this study was to determine if a contextual variable manipulation, water temperature of a bath in which a forearm was immersed, would modulate the reinforcing effects of nitrous oxide (N?O) in healthy volunteers (N?=?12). Each of 2 separate choice experiments consisted of a lukewarm water session and a cold water session. Each session consisted of 3 trials: The 1st 2 were sampling trials in which participants inhaled either 100% oxygen or 40% N?0 for 25 min, and the last trial was a 25-min choice trial, in which participants chose between the 2 agents. In each of the 3 trials, participants immersed their forearm in either ice-cold or lukewarm water for 3 min. A variant of the McNemar test revealed that participants were more likely to choose N?O on cold water sessions than on warm water sessions. The authors conclude that N?O was more reinforcing when participants forearms were immersed in ice-cold water than when immersed in lukewarm water. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Antioxidants, infections and environmental factors in health and disease in northern Finland

Stimulation of motor activity induced by ethanol has been proposed to reflect the positive reinforcing properties of the drug. The present study was designed to assess whether voluntary ethanol intake would stimulate locomotor activity in Sardinian alcohol-preferring (sP) rats, selectively bred for high ethanol preference and consumption. Rats were habituated to a) consume either water alone (water-consuming rats) or ethanol (10%, v/v) as free choice together with water (ethanol-consuming rats) according to a 15-min limited access protocol for 10 consecutive days prior to the test, and b) explore an open field for 10 min immediately after the drinking session in a trial on 3 consecutive days before the test. On the test day, voluntary ethanol consumption in ethanol-consuming rats averaged 1.2 g/kg. Values for activity measures (time spent moving, number of square crossings and number of rearings) were significantly higher in ethanol- than in water-consuming rats at both 5- and 10-min intervals. These results suggest that the euphorigenic effects of ethanol, supposedly represented by the stimulation of locomotor activity, are part of the reinforcing properties of ethanol in sP rats.     

Rewarding affective properties of intra-nucleus accumbens injections of testosterone.

On alternating days, adult male Long-Evans rats implanted with bilateral cannulas in the nucleus accumbens received intracerebral injections of testosterone in a water-soluble cyclodextrin inclusion complex (0.125, 0.25, or 0.5 μg/0.5 μl saline) or saline immediately prior to being confined for 30 min to 1 of 2 compartments of a place-preference apparatus. All rats received 8 days of pairings (4 hormone and 4 saline). On Day 9 the rats were given a 20-min test session during which they had access to all compartments of the apparatus. No hormone was injected prior to the test session. On the test day, rats spent significantly more time in the compartment previously paired with bilateral intra-accumbens injections of testosterone (0.25 and 0.5 μg/0.5 μl saline) than in the compartment previously paired with saline injections. The findings indicate that intra-accumbens injections of testosterone are sufficient to produce reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Effects of chronic and acute cocaine treatment on the onset of maternal behavior and aggression in Sprague-Dawley rats": Correction.

Reports an error in the original article by J. M. Johns et al (Behavioral Neuroscience, 1994[Feb], Vol 108[1], 107–212). On page 108, in the Results, Maternal Behavior, the phrase in parentheses, "(8 min to crouch for 8 min or more of 30 min)' should read: "(6 min to crouch for 8 min or more of 30 min).' On page 109, the label on the upper right panel of Figure 1, "Percent That Crouch in 8 Minutes,' should read: "Percent That Crouch in 6 Minutes.' (The following abstract of this article originally appeared in record 1994-24731-001.) Pregnant rats (N?=?17) were treated either throughout gestation (Gestational Day 1–20) with 30 mg/kg per day (chronic cocaine) or with 1 15-mg/kg dose immediately following parturition (acute cocaine). Chronic and acute cocaine treatment delayed or diminished the postpartum onset of some components of maternal behavior, and chronically treated dams were significantly more aggressive toward a male intruder than acute cocaine-treated or saline-treated dams. Cocaine increased the latency to crouch over pups and decreased crouch duration during a 30-min observation period that immediately followed parturition. Latencies to nest build were also longer in more chronic cocaine-treated dams than in saline controls.… (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effect of peer rating treatments on group morale.

During a training program at a Canadian Forces military indoctrination centre, six intact sub-groups consisting of a total of 166 male Ss were randomly assigned to a control and two experimental groups. Each of the two experimental groups was administered a different form of peer rating treatment. Using a morale survey instrument whose relevance, reliability, and validity were empirically established, pre-treatment and post-treatment measures were derived for the three groups. For the nomination approach peer rating treatment a positive effect on group morale was found (P = .05). No significant effect on group morale was demonstrated for the absolute approach peer rating treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sudden onset aphonia caused by a Japanese-style bath

An 86-year-old man was referred by his family physician to our clinic because of sudden onset aphonia immediately after a Japanese-style bath. On examination, the only abnormality was aphonia, with an otherwise normal physical examination. However, we found vocal fold oedema on laryngeal fibrescopy. For treatment, he was immediately given 30 mg prednisolone intravenously. Twelve hours after injection the oedema had completely disappeared and his aphonia had resolved. The patient was healthy for three months after returning home. However, at the beginning of a cold winter night he again complained of sudden onset hoarseness, after taking a Japanese-style bath. Japanese-style baths are completely different from Western-style baths. There is a temperature difference of almost 30 degrees C between the inside and outside of a bath; the transition may represent a type of physical exercise in elderly and exhausted individuals. This difference could cause a cold or heat-induced allergic reaction. We strongly recommend a laryngeal study in case of sudden onset aphonia.     

Determinants of retention in 8-week-old infants.

Two experiments with 61 8-wk-old infants investigated the effect of amount and distribution of training on Ss' long-term retention. Ss learned to execute an operant footkick to produce movement in an overhead crib mobile in 1 of 2 conditions in which training duration was varied (6, 12, or 18 min) in a single session or held constant and distributed across multiple sessions. The impact of these training factors on retention was assessed immediately following training and after 1- or 2-wk delays. In Exp I, immediate retention following all training durations was high, but only the 18-min duration yielded consistent evidence of retention after 1 wk. In Exp II, distributing 18 training minutes across 3 sessions separated by 24 or 48 hrs promoted retrieval after a 2-wk retention interval, whereas a single 18-min session did not. Data demonstrate that the conditions of original learning influence immediate and long-term retention differentially and suggest that these age-related differences reflect the differential effect of training factors on memory content. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of varied-stimulus exposure training on fear reduction and return of fear

The current investigation assessed the relative treatment benefits of persistence with one specific stimulus vs exposure to multiple versions of a stimulus. The study was a 2 (type of stimulus) x 3 (assessment occasion) design, in which two spider-fearful groups (N = 28) were compared across three different occasions: pre-treatment, post-treatment, and follow-up. Exposure trials were conducted with the same tarantula for participants in the control group, whereas experimental participants were exposed to four novel tarantulas. As predicted, the control group demonstrated significantly more habituation than the experimental group across exposure trials, yet showed a clear return of fear in response to a control spider at a 3-week follow-up assessment whereas the experimental group showed no increase in fear. These findings offer support for the beneficial effects of varying the stimulus during exposure, and challenge the reliance on indices of fear activation and habituation as accurate signals of the permanence of fear reduction.     

Feedback-aided self-regulation of skin temperature with a single feedback locus. I. Acquisition and reversal training

A technique has been developed that enables most humans to establish rapid self-regulatory control of their own skin temperature when provided with immediate visual feedback information concerning variations in local skin temperature. Training took place during 15-min periods within 45-min sessions. Clear evidence of learning was usually manifested within 4 sessions. After acquisition occurred, mean change per session was approximately 2.2 degrees F, ranging up to 6.5 degrees F. Training was continued with some subjects who were taught to alter temperature in opposite directions during successive periods on the same day. After practice, these subjects routinely displayed ranges of 9-14 degrees F within 15 min.     

Danger ideation reduction therapy (DIRT) for obsessive-compulsive washers. A controlled trial

Twenty-one OCD sufferers with washing/contamination concerns took part in a controlled treatment trial at the Anxiety Disorders Clinic, University of Sydney. Eleven of the subjects received danger ideation reduction therapy (DIRT) over eight, 1 h weekly group sessions conducted by the second author. Ten subjects were placed on a wait list and did not receive DIRT or any other treatment. DIRT procedures were solely directed at decreasing danger-related expectancies concerning contamination and did not include exposure, response prevention or behavioral experiments. Components of DIRT include attentional focusing, filmed interviews, corrective information, cognitive restructuring, expert testimony, microbiological experiments and a probability of catastrophe assessment task. All subjects were assessed at pre-treatment, post-treatment and three-month follow-up using the Maudsley Obsessional-Compulsive Inventory, Leyton Obsessionality Inventory, Beck Depression Inventory and a Self Rating of Severity Scale. Changes from pre-treatment to after treatment (post-treatment and follow-up scores averaged) were significantly greater in the DIRT condition than in the control condition for all measures. No significant differences were obtained between groups on post-treatment to follow-up change on any measure. The implications of these findings for theoretical models of OCD and its management are discussed.     

Effects of social deprivation and satiation on the reinforcing properties of social stimulation in chronic male hospitalized schizophrenics.

Hypothesized that (a) pre-experimental social deprivation will lead to an increase in the reinforcing properties of social stimulation, and (b) pre-experimental social satiation will lead to a decrease in the reinforcing properties of social stimulation. Ss were 16 chronic male 38-59 yr old schizophrenics. Ss in the social deprivation groups were isolated for 45 min before they were given a simple marble-dropping task. Ss in the social satiation groups received a 10-min undemanding conversation with E before each experimental session. Social contact with E was significantly more often sought than avoided following 45 min of social deprivation, whereas social contact was avoided significantly more often following 10 min of social satiation. (22 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the acquisition of dimensional stimulus control by the pigeon.

Trained 80 domestic pigeons to peck a white illuminated key for variable interval (VI) reinforcement. Ss were tested for angularity generalization following 0, 5, 10, or 20 min. of VI-reinforced exposure to a given line angle. For 40 Ss, the line angle was 90–; for the others, 30–. The 0-min Ss showed a systematic preference for 90–; however, 5 min. of training (with either SD value) produced nondifferential responding during generalization testing. Both 10 and 20 min. of training produced reliable gradients peaking at the SD values, with the 20-min gradient sharper but not reliably so. Furthermore, the 2 20-min gradients, peaking at 90– and 30–, were equal in slope. The various groups did not differ reliably in absolute level of responding during generalization testing, suggesting that response strength was fully established prior to the introduction of line training. Under this condition, dimensional stimulus control was acquired very rapidly and initial stimulus preferences were as rapidly overcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evaluation of lidocaine in human inferior alveolar nerve block

The purpose of this study was to measure the degree of anesthesia following the administration of 3.6 ml of 2% lidocaine solutions with either 1:50,000, 1:80,000, or 1:100,000 for inferior alveolar nerve block and to compare the results with those obtained following the administration of 1.8 ml of the same solutions (1). With the use of a repeated measures design, 30 subjects randomly received an inferior alveolar injection at three successive appointments. The first molar, first premolar, lateral incisor, and contralateral canine (control) were blindly tested with an Analytic Technology pulp tester at 3-min cycles for 50 min. The degree of anesthesia was comparable for the three solutions following the administration of 3.6 ml of each solution. Retrospective evaluation showed that the volume of the solution influenced the degree of anesthesia.     

Human methadone self-administration: Effects of diazepam pretreatment.

The effect of diazepam on methadone self-administration was examined. Five methadone maintained patients with a history of benzodiazepine abuse were recruited, Patients were stabilized on 80 mg of methadone per day. After stabilization patients participated in methadone self-administration sessions. During each session, 128 presses (fixed ratio 128) of 1 button delivered 10 ml of 0.054 mg/ml methadone solution. The same number of button presses on a 2nd button delivered 10 ml of vehicle. Forty-five min prior to the self-administration session, 0 (placebo), 5, 10, or 20 mg per 70 kg body weight diazepam was administered. Ratings of drug liking, goodness, strength, and high were collected 5, 30, 60, 90, and 150 min after the end of the self-administration session. Diazepam pretreatment significantly decreased the amount of methadone consumed. The 10- and 20-mg diazepam doses significantly increased reports of good, like, strong, and high. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intrathecal adenosine administration: a phase 1 clinical safety study in healthy volunteers, with additional evaluation of its influence on sensory thresholds and experimental pain

BACKGROUND: Several animal studies show antinociceptive effects of intrathecally administered adenosine and its analogs. However, there is no clinical experience regarding the effects of intrathecal adenosine in humans. METHODS: The side effects and analgesic effects of intrathecal adenosine (500-2,000 microg) on experimental pain were studied in 12 healthy volunteers. Before and after adenosine was given, the authors evaluated the cold pain rating of the foot (submersion in ice water for 1 min), the forearm ischemic pain rating during a 30-min tourniquet test, and the thermal and tactile pain thresholds on healthy and inflamed skin after application of mustard oil (4 min) to the calf. The areas of secondary allodynia surrounding the inflammation were also determined. The cerebrospinal fluid level of adenosine was determined before and after injection. RESULTS: Intrathecal adenosine caused a 1,000- to 2,000-fold elevation of the cerebrospinal fluid concentration. One volunteer experienced transient (30 min) lumbar pain after injection at a dose of 2,000 microg. There were no other complications in any other volunteers. Adenosine reduced, in a non-dose-dependent manner, the areas of secondary allodynia after skin inflammation (brush, P < 0.06; and von Frey hair, P < 0.03) and reduced the forearm tourniquet ischemic pain rating (P = 0.01). Tactile pain thresholds were significantly reduced by mustard oil inflammation during control, whereas adenosine treatment prevented this reduction. The ice water-induced cold pain rating was not influenced by adenosine. CONCLUSIONS: An intrathecal adenosine injection of 1,000 microg lacked side effects in healthy volunteers. The compound attenuated different types of experimental pain.     

Is it possible to perform immediate cardiac assist using untrained latissimus dorsi muscle in a work-rest regimen?

The authors investigated what contractile force (CF) could be obtained from unconditioned latissimus dorsi muscle immediately after mobilization and for the 2 week vascular period of recovery. Latissimus dorsi muscle mobilization was performed on seven adult (4 experimental and 3 control) sheep leaving only the pedicle and the peripheral muscle intact. Telectronics stimulators (Myostim 7220; Teletronics Pacing Systems, Inc, Englewood, CO) were implanted. Immediately after mobilization 11-35% of the initial CF was lost. A 30 min fatigue test was performed 1 hr after mobilization (20 g/kg preload, 10 V, 10 Hz, 15 BPM, 6 impulses per burst) using a 1 min work-1 min rest regimen. Two sheep lost 2-12% of initial CF; two increased CF by 14-24%. At the end of the fatigue test, CF consisted of 74-89% of immobilized CF. Electrical stimulation training of the muscle was then initiated with the following regimen in the experimental animals only: 15 BPM, single impulses, 5 V, 10 Hz. Every day the muscle was exercised using a work-rest regimen to mimic cardiac assist, starting with 20 min on day 2, and increasing by 2 min per day until a total of 50 min was reached on day 16. All animals were retested for CF using a 42 min fatigue test on days 6, 11, and 16. On day 6, there was no fatigue evident in the experimental group during the 42 min test. CF after testing was 59-81% (mean 67%) of initial data. In the control group (animals with no electrical stimulation training protocol), CF decreased by 11% (from 64 to 53%). On day 11, there was no fatigue evident in the experimental group; CF in all animals increased by 2-8%. On day 16, there was also no fatigue evident in the experimental group; CF increased by 0-9%. An additional 20 min of continuous contraction (15 BPM) fatigue testing was performed on the muscle without rest between the tests. No fatigue was evident at the end of testing. Light microscopic analysis of latissimus dorsi muscle biopsy specimens taken on the days of testing showed no evidence of necrotic damage. Our investigations suggest that it may be possible to start muscle transformation immediately after mobilization and use the untrained latissimus dorsi muscle for cardiac assist immediately after surgery for short periods.     

Effect of proactive inhibition upon the postdiscrimination generalization gradient.

Gave wavelength-discrimination or discrimination-reversal training to 8 groups of 12 naive domestic pigeons in an operant free-responding paradigm. 4 groups were trained, for 30 min. daily, to criterion. 2 of these groups learned the 2nd (reversal) task in a single continuous session (massed practice), while the 2 others continued with 30-min sessions (distributed practice). 4 control groups experienced only the 2nd discrimination, with either massed or distributed practice. All groups were then tested for generalization either immediately or 24 hr. after reaching criterion on the 2nd task. The reversal had no effect on immediate-test gradients. In the delayed test, however, the massed-practice reversal gradient was flatter and showed less area shift than the others, suggesting a proactive inhibition effect. (21 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of chronic and acute cocaine treatment on the onset of maternal behavior and aggression in Sprague-Dawley rats.

Pregnant rats (N?=?17) were treated either throughout gestation (Gestational Day 1–20) with 30 mg/kg per day (chronic cocaine) or with 1 15-mg/kg dose immediately following parturition (acute cocaine). Chronic and acute cocaine treatment delayed or diminished the postpartum onset of some components of maternal behavior, and chronically treated dams were significantly more aggressive toward a male intruder than acute cocaine-treated or saline-treated dams. Cocaine increased the latency to crouch over pups and decreased crouch duration during a 30-min observation period that immediately followed parturition. Latencies to nest build were also longer in more chronic cocaine-treated dams than in saline controls. On Day 6 postpartum, 83% of chronic cocaine-treated dams pinned and attacked an intruder male 8 or more times during a 10-min observation period, whereas only 4% of acute cocaine-treated and none of the saline-treated dams exhibited this much aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)