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Self-assessment is the most common method for monitoring performance and safety in the workplace. However, discrepancies between subjective and objective measures have increased interest in physiological assessment of performance. In a double-blind placebo-controlled study, 23 healthy adults were randomly assigned to either a placebo (n = 11; 5 F, 6 M) or caffeine condition (n = 12; 4 F, 8 M) while undergoing 50 h (i.e. two days) of total sleep deprivation. In previous work, higher salivary alpha-amylase (sAA) levels were associated with improved psychomotor vigilance and simulated driving performance in the placebo condition. In this follow-up article, the effects of strategic caffeine administration on the previously reported diurnal profiles of sAA and performance, and the association between sAA and neurobehavioural performance were investigated. Participants were given a 10 h baseline sleep opportunity (monitored via standard polysomnography techniques) prior to undergoing sleep deprivation (total sleep time: placebo = 8.83 ± 0.48 h; caffeine = 9.01 ± 0.48 h). During sleep deprivation, caffeine gum (200 mg) was administered at 01:00 h, 03:00 h, 05:00 h, and 07:00 h to participants in the caffeine condition (n = 12). This strategic administration of caffeine gum (200 mg) has been shown to be effective at maintaining cognitive performance during extended wakefulness. Saliva samples were collected, and psychomotor vigilance and simulated driving performance assessed at three-hour intervals throughout wakefulness. Caffeine effects on diurnal variability were compared with previously reported findings in the placebo condition (n = 11). The impact of caffeine on the circadian profile of sAA coincided with changes in neurobehavioural performance. Higher sAA levels were associated with improved performance on the psychomotor vigilance test during the first 24 h of wakefulness in the caffeine condition. However, only the association between sAA and response speed (i.e. reciprocal-transform of mean reaction time) was consistent across both days of sleep deprivation. The association between sAA and driving performance was not consistent across both days of sleep deprivation. Results show that the relationship between sAA and reciprocal-transform of mean reaction time on the psychomotor vigilance test persisted in the presence of caffeine, however the association was relatively weaker as compared with the placebo condition. Refereed/Peer-reviewed

This study examined the impact of eating during simulated night shift on performance and subjective complaints. Subjects were randomized to eating at night (n=5; 23.2 ± 5.5 y) or not eating at night (n=5; 26.2 ± 6.4 y). All participants were given one sleep opportunity of 8 h (22:00 h-06:00 h) before transitioning to the night shift protocol. During the four days of simulated night shift participants were awake from 16:00 h-10:00 h with a daytime sleep of 6 h (10:00 h-16:00 h). In the simulated night shift protocol, meals were provided at ≈0700 h, 1900 h and 0130 h (eating at night); or ≈0700 h, 0930 h, 1410 h and 1900 h (not eating at night). Subjects completed sleepiness, hunger and gastric complaint scales, a Digit Symbol Substitution Task and a 10-min Psychomotor Vigilance Task. Increased sleepiness and performance impairment was evident in both conditions at 0400 h (p < 0.05). Performance impairment at 0400 h was exacerbated when eating at night. Not eating at night was associated with elevated hunger and a small but significant elevation in stomach upset across the night (p < 0.026). Eating at night was associated with elevated bloating on night one, which decreased across the protocol. Restricting food intake may limit performance impairments at night. Dietary recommendations to improve night-shift performance must also consider worker comfort. Refereed/Peer-reviewed

Shiftworkers have impaired performance when driving at night and they also alter their eating patterns during nightshifts. However, it is unknown whether driving at night is influenced by the timing of eating. This study aims to explore the effects of timing of eating on simulated driving performance across four simulated nightshifts. Healthy, non-shiftworking males aged 18–35 years (n = 10) were allocated to either an eating at night (n = 5) or no eating at night (n = 5) condition. During the simulated nightshifts at 1730, 2030 and 0300 h, participants performed a 40-min driving simulation, 3-min Psychomotor Vigilance Task (PVT-B), and recorded their ratings of sleepiness on a subjective scale. Participants had a 6-h sleep opportunity during the day (1000–1600 h). Total 24-h food intake was consistent across groups; however, those in the eating at night condition ate a large meal (30% of 24-h intake) during the nightshift at 0130 h. It was found that participants in both conditions experienced increased sleepiness and PVT-B impairments at 0300 h compared to 1730 and 2030 h (p < 0.001). Further, at 0300 h, those in the eating condition displayed a significant decrease in time spent in the safe zone (p < 0.05; percentage of time within 10 km/h of the speed limit and 0.8 m of the centre of the lane) and significant increases in speed variability (p < 0.001), subjective sleepiness (p < 0.01) and number of crashes (p < 0.01) compared to those in the no eating condition. Results suggest that, for optimal performance, shiftworkers should consider restricting food intake during the night. Refereed/Peer-reviewed

Technology-supported methods for sleep recording are becoming increasingly affordable. Sleep history feedback may help with fatigue-related decision making - Should I drive? Am I fit for work? This study examines a "sleep tank" model (SleepTank ™ ), which is analogous to the fuel tank in a car, refilled by sleep, and depleted during wake. Required inputs are sleep period time and sleep efficiency (provided by many consumer-grade actigraphs). Outputs include suggested hours remaining to "get sleep" and percentage remaining in tank (Tank%). Initial proof of co ncept analyses were conducted using data from a laboratory-based simulated nightshift study. Ten, healthy males (18-35y) undertook an 8h baseline sleep opportunity and daytime performance testing (BL), followed by four simulated nightshifts (2000 h-0600 h), with daytime sleep opportunities (1000 h-1600 h), then an 8 h night-time sleep opportunity to return to daytime schedule (RTDS), followed by daytime performance testing. Psychomotor Vigilance Task (PVT) and Karolinska Sleepiness Scale were performed at 1200 h on BL and RTDS, and at 1830 h, 2130 h 0000 h and 0400 h each nightshift. A 40-minute York Driving Simulation was performed at 1730 h, 2030 h and 0300 h on each nightshift. Model outputs were calculated using sleep period timing and sleep efficiency (from polysomnography) for each participant. Tank% was a significant predictor of PVT lapses (p < 0.001), and KSS (p < 0.001), such that every 5% reduction resulted in an increase of two lapses, or one point on the KSS. Tank% was also a significant predictor of %time in the Safe Zone from the driving simulator (p = 0.001), such that every 1% increase in the tank resulted in a 0.75% increase in time spent in the Safe Zone. Initial examination of the correspondence between model predictions and performance and sleepiness measures indicated relatively good predictive value. Results provide tentative evidence that this "sleep tank" model may be an informative tool to aid in individual decision-making based on sleep history. Refereed/Peer-reviewed

Eating during the night may increase the risk for obesity and type 2 diabetes in shift workers. This study examined the impact of either eating or not eating a meal at night on glucose metabolism. Participants underwent four nights of simulated night work (SW1–4, 16:00–10:00 h

During sleep deprivation, neurobehavioral functions requiring sustained levels of attention and alertness are significantly impaired. Discrepancies between subjective measures of sleepiness and objective performance during sustained operations have led to interest in physiological monitoring of operator performance. Alertness, vigilance, and arousal are modulated by the wake-promoting actions of the central noradrenergic system. Salivary alpha-amylase (sAA) has been proposed as a sensitive peripheral measure of noradrenergic activity, but limited research has investigated the relationship between sAA and performance. In a laboratory-controlled environment, we investigated the relationship between sAA levels, subjective sleepiness, and performance during two days (50 h) of total sleep deprivation. Beginning at 09:00, twelve healthy participants (5 females) aged 22.5 ± 2.5 years (mean ± SD) provided saliva samples, recorded ratings of subjective sleepiness, completed a brief 3-min psychomotor vigilance task (PVT-B) and performed a 40-min simulated driving task, at regular 3 h intervals during wakefulness. Ratings of subjective sleepiness exhibited a constant linear increase (p

An automatic pipette is a key piece of laboratory equipment. The ability to accurately and reproducibly deliver any volume is a critical skill to master for all undergraduate students in the laboratory sciences. Over many years we have noted that students struggle in learning several facets of correct pipette usage. These include, choosing the correct pipette for a given volume, correctly setting the pipette and correctly using the plunger to aspirate and dispense the liquid. Students also struggle with unit conversions between ml and μl and vice versa. Lastly, students fail to retain these skills and information in following semesters of teaching. In an attempt to help students with converting between units (μl and ml) as well as choosing the most appropriate pipette for a given volume, I developed an interactive simulation which covered all these major aspects. Using a Gilson pipette as an example, the simulation covered how to set the pipette for a number of defined volumes. An Android/iOS app of the simulation has also been developed which can be used during laboratory classes. In 2017, we polled first year undergraduate students about their level of experience, knowledge of pipettes and level of comfort in converting between units and we then explained the simulation to them. The feedback on their skills and the software will be discussed. We also tested the impact of the simulation using 2nd year students enrolled in genetics. Using a laboratory quiz, we found significant improvements in student performance when students used the simulation compared to those that did not. We suggest this interactive approach is a simple and effective way to enhance student learning of key aspects of laboratory pipettes. The simulation is freely available.

Background: There is an absence of high quality research to support the use of the Therapressure ProgramTM. This pilot study aimed at developing appropriate research protocols to investigate the effectiveness of the Therapressure ProgramTM on the stress response in children with sensory overresponsivity. Method: A one-group pre-test/post-test repeated measures design was conducted using a convenience sample. Six children (6-8 years of age) with sensory overresponsivity received 14 consecutive days of the Therapressure ProgramTM by their parents at home. Parents concurrently collected salivary cortisol samples from their children. Results: Children with sensory overresponsivity displayed both hyper- and hypo-cortisolism at baseline. All of the children’s cortisol levels shifted toward a normative range after intervention. Aspects have been identified related to the data collection protocol. Conclusion: When testing children with sensory overresponsivity who are constantly activating their stress response system, we raise awareness of the need to check for both hyper- and hypo-cortisolism during statistical analysis. Preliminary pilot data may also show modulation of sympathetic arousal following the intervention. Further research is warranted and recommendations are made related to data collection protocols. Refereed/Peer-reviewed

Caffeine has been shown to minimise the effects of sleep loss on performance and alertness. However, caffeine may also have negative repercussions for recovery sleep, particularly during the daytime. The current study investigated the impact of high caffeine consumption on daytime recovery sleep following 50 h wakefulness. Twenty-four healthy participants were randomly assigned to either a caffeine (n = 12, aged 22.5 +/- 3.3 years) or placebo condition (n = 12, aged 22.5 +/- 2.5 years). All participants were scheduled to one baseline sleep (22:00-08:00 h) and two nights (50 h) of wakefulness followed by a daytime recovery sleep (10:00-19:00 h). Each night at 01:00, 03:00, 05:00 and 07:00 h during the wake period participants were given 200 mg of caffeine or placebo gum. Caffeine reduced the amount of SWS within the first NREM-REM sleep cycles compared to placebo. However, there were no differences between the caffeine and placebo conditions with relation to the overall amount of SWS, REM sleep, stage 2 sleep, and sleep initiation and consolidation during the recovery sleep. Results suggest that caffeine can be used as a fatigue countermeasure in industries where work hours extend to 50 h without significantly disrupting recovery sleep, even during the daytime. Results may also have implications for workers working extended shifts who use caffeine to help reduce fatigue during the commute home. Refereed/Peer-reviewed

The current study investigated the effects of repeated caffeine administration on performance and subjective reports of sleepiness and fatigue during 50 h extended wakefulness. Twenty-four, non-smokers aged 22.5 ± 2.9 y (mean ± SD) remained awake for two nights (50 h) in a controlled laboratory environment. During this period, 200 mg of caffeine or placebo gum was administered at 01:00, 03:00, 05:00 and 07:00 on both nights (total of 800 mg/night). Neurobehavioral performance and subjective reports were assessed throughout the wake period. Caffeine improved performance compared to placebo, but did not affect overall ratings of subjective sleepiness and fatigue. Performance and sleepiness worsened with increasing time awake for both conditions. However, caffeine slowed performance impairments such that after 50 h of wakefulness performance was better following caffeine administration compared to placebo. Caffeine also slowed the increase in subjective sleepiness and performance ratings, but only during the first night of wakefulness. After two nights of sleep deprivation, there was no difference in sleepiness ratings between the two conditions. These results demonstrate that strategic administration of caffeine effectively mitigates performance impairments associated with 50 h wakefulness but does not improve overall subjective assessments of sleepiness, fatigue and performance. Results indicate that while performance impairment is alleviated, individuals may continue to report feelings of sleepiness. Individuals who use caffeine as a countermeasure in sustained operations may feel as though caffeine is not effective despite impairments in objective performance being largely mitigated.

There is a complex relationship between drug dependence and stress, with alcohol and other drugs of abuse both relieving stress and potentially inducing physiological stress responses in the user. Opioid drugs have been shown to modulate hypothalamic-pituitary-adrenal (HPA) activity in animal models and individual response to this modulation may play a role in continuation of drug use. Healthy young Caucasian adults were administered a single dose of immediate release oxycodone (20 mg, n = 30) or assigned to a control group (n = 19) that was not administered the drug. At 0, 1, 2, 4 and 6 h post-administration, blood and saliva samples were collected along with assessment of pupil diameter. The HPA response was determined by measurement of salivary cortisol through a commercially available enzyme-linked immunosorbent assay (ELISA). The results were compared to genotype at the - 511 and - 31 positions in the interleukin1B (IL1B) gene. No difference in cortisol production was initially observed between the two groups, however, when participants were separated based on their genotype for two single nucleotide polymorphisms in the promoter of the IL1B gene, which have been shown to occur at a higher frequency in opioid-dependent populations, individuals carrying the - 511 T and - 31 C alleles (- 511 C/T, - 31 C/T or - 511 T/T, - 31 C/C) had a significantly (p < 0.05) higher cortisol levels compared to individuals homozygous for the - 511 C and - 31 T alleles. These results suggest that individuals carrying the - 511 T and - 31 C alleles experience HPA activation in response to opioid administration and therefore may be less likely to undertake subsequent self-administration. Refereed/Peer-reviewed

The flavonoid pigment pathway in plants has been used as a model system for studying gene regulatory mechanisms. C2-Idf is a stable dominant mutation of the chalcone synthase gene, c2, which encodes the first dedicated enzyme in this biosynthetic pathway of maize. Homozygous C2-Idf plants show no pigmentation. This allele also inhibits expression of functional C2 alleles in heterozygotes, producing a less pigmented condition instead of the normal deeply pigmented phenotype. To explore the nature of this effect, the C2-Idf allele was cloned. The gene structure of the C2-Idf haplotype differs substantially from that of the normal c2 gene in that three copies are present. Two of these are located in close proximity to each other in a head-to-head orientation and the third is closely linked. Previous experiments showed that the lower level of pigmentation in heterozygotes is correlated with reduced enzyme activity and low steady-state mRNA levels. We found that c2 transcription occurs in nuclei of C2-Idf/C2 heterozygotes, but mRNA does not accumulate, suggesting that the inhibition is mediated by RNA silencing. Infection of C2-Idf/C2 heterozygotes with viruses that carry suppressors of RNA silencing relieved the phenotypic inhibition, restoring pigment production and mRNA levels. Finally, we detected small interfering RNAs (siRNAs) in plants carrying C2-Idf, but not in plants homozygous for the wild-type C2 allele. Together, our results indicate that the inhibitory effect of C2-Idf occurs through RNA silencing.

Use of illicit stimulants such as methamphetamine, cocaine, and ecstasy is an increasing health problem. Chronic use can cause neurotoxicity in animals and humans but the long-term consequences are not well understood. The aim of the current study was to investigate the long-term effect of stimulant use on the morphology of the human substantia nigra. We hypothesised that history of illicit stimulant use is associated with an abnormally bright and enlarged substantia nigra (termed 'hyperechogenicity') when viewed with transcranial sonography. Substantia nigra morphology was assessed in abstinent stimulant users (n = 36; 31±9 yrs) and in two groups of control subjects: non-drug users (n = 29; 24±5 yrs) and cannabis users (n = 12; 25±7 yrs). Substantia nigra morphology was viewed with transcranial sonography and the area of echogenicity at the anatomical site of the substantia nigra was measured at its greatest extent. The area of substantia nigra echogenicity was significantly larger in the stimulant group (0.273±0.078 cm2) than in the control (0.201±0.054 cm2; P

BACKGROUND: A central model for chronic tension-type headache (CTH) posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. The prediction from this model that pain sensitivity mediates the relationship between stress and headache activity has not yet been examined.OBJECTIVE: To determine whether pain sensitivity mediates the relationship between stress and prospective headache activity in CTH sufferers.METHOD: Self-reported stress, pain sensitivity and prospective headache activity were measured in 53 CTH sufferers recruited from the general population. Pain sensitivity was modelled as a mediator between stress and headache activity, and tested using a nonparametric bootstrap analysis.RESULTS: Pain sensitivity significantly mediated the relationship between stress and headache intensity.CONCLUSIONS: The results of the present study support the central model for CTH, which posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. Implications for the mechanisms and treatment of CTH are discussed.

Aims: Inspection Time (IT) is used to assess speed of information processing in a manner that, unlike other cognitive tests,is independent of motor components and reaction time. IT has been utilised to assess a range of disruptions in brain activity and is affected by drugs such as alcohol, but there is no information on the effect of acute opioid administration. We hypothesised that acute opioid administration would produce a concentrationrelated increase in IT comparable to that produced by moderatedoses of alcohol. Refereed/Peer-reviewed

Paramutation has been studied extensively in maize since R.A. Brink described a heritable alteration of the r locus that defied principles of Mendelian inheritance ([Brink, 1956][1]). A recent publication on paramutation in maize now provides convincing evidence that chromatin-level regulation

BACKGROUND: Tension-type headache is the most common form of headache and its chronic form, chronic tension-type headache (CTTH), is one of the most difficult to treat. The etiology of CTTH is not well understood, but is believed to be multifactorial and to vary among individuals. In the present study, the authors sought to identify common mechanisms of CTTH pathology. Empirical studies have implicated various immunomodulatory cytokines as mediators of chronic pain disorders, including CTTH.OBJECTIVES: To determine the role of peripheral cytokines and genetic factors in the development of CTTH.METHODS: A panel of cytokines hypothesized to play a role in the pathogenesis of CTTH was measured using cytometric bead arrays and ELISAs in 56 individuals with CTTH and 42 healthy control participants between 18 and 65 years of age.RESULTS: Levels of interleukin (IL)-1β were significantly elevated in participants diagnosed with CTTH relative to healthy controls, while IL-18 levels were found to be significantly elevated in men with CTTH. Because the levels of these immune mediators were increased in the apparent absence of injury or infection, the authors sought to determine whether genetic changes were responsible for fluctuations in cytokine levels. Polymerase chain reaction and restriction fragment length polymorphism analyses were used to determine individual genotypes at key single nucleotide polymorphism positions in theIL-1Bgene. No association was observed between CTTH and single nucleotide polymorphisms in the IL-1β gene.CONCLUSIONS: These findings suggest that increases in key proinflammatory cytokine levels are associated with CTTH and the pathology of the disorder involves sterile neurovascular inflammation.