Distribution of dim light melatonin offset (DLMOff) and phase relationship to waketime in healthy adults and associations with chronotype.

OBJECTIVES: Dim light melatonin onset, or the rise in melatonin levels representing the beginning of the biological night, is the gold standard indicator of circadian phase. Considerably less is known about dim light melatonin offset, or the decrease in melatonin to low daytime levels representing the end of the biological night. In the context of insufficient sleep, morning circadian misalignment, or energy intake after waketime but before dim light melatonin offset, is linked to impaired insulin sensitivity, suggesting the need to characterize dim light melatonin offset and identify risk for morning circadian misalignment. METHODS: We examined the distributions of dim light melatonin offset clock hour and the phase relationship between dim light melatonin offset and waketime, and associations between dim light melatonin offset, phase relationship, and chronotype in healthy adults (N = 62) who completed baseline protocols measuring components of the circadian melatonin rhythm and chronotype. RESULTS: 74.4% demonstrated dim light melatonin offset after waketime, indicating most healthy adults wake up before the end of biological night. Later chronotype (morningness-eveningness, mid-sleep on free days corrected, and average mid-sleep) was associated with later dim light melatonin offset clock hour. Later chronotype was also associated with a larger, positive phase relationship between dim light melatonin offset and waketime, except for morningness-eveningness. CONCLUSIONS: These findings suggest morning circadian misalignment risk among healthy adults, which would not be detected if only dim light melatonin onset were assessed. Chronotype measured by sleep timing may better predict this risk in healthy adults keeping a consistent sleep schedule than morningness-eveningness preferences. Additional research is needed to develop circadian biomarkers to predict dim light melatonin offset and evaluate appropriate dim light melatonin offset timing to promote health.

Activating Adult Allies From a Rural Community on Lesbian, Gay, Bisexual, Transgender, and Queer Student Issues in School Using Photovoice.

PURPOSE: Many students who are lesbian, gay, bisexual, transgender, or queer (LGBTQ) face hostile school environments that can negatively impact their mental health and education. This study involved a photovoice project where high school students from a Gay-Straight Alliance in the rural southeastern United States took photographs that depicted the issues LGBTQ students were facing and then exhibited their photographs and stories to individuals from the school system and local community to promote awareness, dialogue, and action. METHODS: 20 adults who attended the photovoiceexhibit responded to an online survey about their experiences with the intervention. RESULTS: 85% of adults reported that the interventionmade them think about issues they had not previously considered, including the struggles LGBTQ youth face, gender issues, and living in a rural community. Common emotions experienced at the interventionincluded feeling excited, concern for the youth, and proud of the youth. Further, 81% of the adults indicated that they would take action or behave differently as a result of the intervention, including supporting and affirming LGBTQ students, using gender-neutral and -inclusive language, and confronting bias in themselves and others. CONCLUSIONS: Photovoice is a promising strategy for LGBTQ students to activate adult allies in their community.

Morning Circadian Misalignment during Short Sleep Duration Impacts Insulin Sensitivity.

Short sleep duration and circadian misalignment are hypothesized to causally contribute to health problems including obesity, diabetes, metabolic syndrome, heart disease, mood disorders, cognitive impairment, and accidents. Here, we investigated the influence of morning circadian misalignment induced by an imposed short nighttime sleep schedule on impaired insulin sensitivity, a precursor to diabetes. Imposed short sleep duration resulted in morning wakefulness occurring during the biological night (i.e., circadian misalignment)-a time when endogenous melatonin levels were still high indicating the internal circadian clock was still promoting sleep and related functions. We show the longer melatonin levels remained high after wake time, insulin sensitivity worsened. Overall, we find a simulated 5-day work week of 5-hr-per-night sleep opportunities and ad libitum food intake resulted in ∼20% reduced oral and intravenous insulin sensitivity in otherwise healthy men and women. Reduced insulin sensitivity was compensated by an increased insulin response to glucose, which may reflect an initial physiological adaptation to maintain normal blood sugar levels during sleep loss. Furthermore, we find that transitioning from the imposed short sleep schedule to 9-hr sleep opportunities for 3 days restored oral insulin sensitivity to baseline, but 5 days with 9-hr sleep opportunities was insufficient to restore intravenous insulin sensitivity to baseline. These findings indicate morning wakefulness and eating during the biological night is a novel mechanism by which short sleep duration contributes to metabolic dysregulation and suggests food intake during the biological night may contribute to other health problems associated with short sleep duration.

Acetic acid inhibits nutrient uptake in Saccharomyces cerevisiae: auxotrophy confounds the use of yeast deletion libraries for strain improvement.

Acetic acid inhibition of yeast fermentation has a negative impact in several industrial processes. As an initial step in the construction of a Saccharomyces cerevisiae strain with increased tolerance for acetic acid, mutations conferring resistance were identified by screening a library of deletion mutants in a multiply auxotrophic genetic background. Of the 23 identified mutations, 11 were then introduced into a prototrophic laboratory strain for further evaluation. Because none of the 11 mutations was found to increase resistance in the prototrophic strain, potential interference by the auxotrophic mutations themselves was investigated. Mutants carrying single auxotrophic mutations were constructed and found to be more sensitive to growth inhibition by acetic acid than an otherwise isogenic prototrophic strain. At a concentration of 80 mM acetic acid at pH 4.8, the initial uptake of uracil, leucine, lysine, histidine, tryptophan, phosphate, and glucose was lower in the prototrophic strain than in a non-acetic acid-treated control. These findings are consistent with two mechanisms by which nutrient uptake may be inhibited. Intracellular adenosine triphosphate (ATP) levels were severely decreased upon acetic acid treatment, which likely slowed ATP-dependent proton symport, the major form of transport in yeast for nutrients other than glucose. In addition, the expression of genes encoding some nutrient transporters was repressed by acetic acid, including HXT1 and HXT3 that encode glucose transporters that operate by facilitated diffusion. These results illustrate how commonly used genetic markers in yeast deletion libraries complicate the effort to isolate strains with increased acetic acid resistance.

Impact of insufficient sleep on total daily energy expenditure, food intake, and weight gain.

Insufficient sleep is associated with obesity, yet little is known about how repeated nights of insufficient sleep influence energy expenditure and balance. We studied 16 adults in a 14- to 15-d-long inpatient study and quantified effects of 5 d of insufficient sleep, equivalent to a work week, on energy expenditure and energy intake compared with adequate sleep. We found that insufficient sleep increased total daily energy expenditure by ∼5%; however, energy intake--especially at night after dinner--was in excess of energy needed to maintain energy balance. Insufficient sleep led to 0.82 ± 0.47 kg (±SD) weight gain despite changes in hunger and satiety hormones ghrelin and leptin, and peptide YY, which signaled excess energy stores. Insufficient sleep delayed circadian melatonin phase and also led to an earlier circadian phase of wake time. Sex differences showed women, not men, maintained weight during adequate sleep, whereas insufficient sleep reduced dietary restraint and led to weight gain in women. Our findings suggest that increased food intake during insufficient sleep is a physiological adaptation to provide energy needed to sustain additional wakefulness; yet when food is easily accessible, intake surpasses that needed. We also found that transitioning from an insufficient to adequate/recovery sleep schedule decreased energy intake, especially of fats and carbohydrates, and led to -0.03 ± 0.50 kg weight loss. These findings provide evidence that sleep plays a key role in energy metabolism. Importantly, they demonstrate physiological and behavioral mechanisms by which insufficient sleep may contribute to overweight and obesity.

Can small shifts in circadian phase affect performance?

Small shifts in circadian timing occur frequently as a result of daylight saving time or later weekend sleep. These subtle shifts in circadian phase have been shown to influence subjective sleepiness, but it remains unclear if they can significantly affect performance. In a retrospective analysis we examined performance on the Psychomotor Vigilance Test before bedtime and after wake time in 11 healthy adults on fixed sleep schedules based on their habitual sleep times. The dim light melatonin onset, a marker of circadian timing, was measured on two occasions. An average 1.1 h shift away from a proposed optimal circadian phase angle (6 h between melatonin onset and midpoint of sleep) significantly slowed mean, median and fastest 10% reaction times before bedtime and after wake time (p < 0.05). These results add to previous reports that suggest that humans may be sensitive to commonly occurring small shifts in circadian timing.

Identification of gold nanoparticle-resistant mutants of Saccharomyces cerevisiae suggests a role for respiratory metabolism in mediating toxicity.

Positively charged gold nanoparticles (0.8-nm core diameter) reduced yeast survival, but not growth, at a concentration of 10 to 100 µg/ml. Among 17 resistant deletion mutants isolated in a genome-wide screen, highly significant enrichment was observed for respiration-deficient mutants lacking genes encoding proteins associated with the mitochondrion.

Blacks (African Americans) have shorter free-running circadian periods than whites (Caucasian Americans).

The length of the free-running period (τ) affects how an animal re-entrains after phase shifts of the light-dark (LD) cycle. Those with shorter periods adapt faster to phase advances than those with longer periods, whereas those with longer periods adapt faster to phase delays than those with shorter periods. The free-running period of humans, measured in temporal isolation units and in forced desychrony protocols in which the day length is set beyond the range of entrainment, varies from about 23.5 to 26 h, depending on the individual and the experimental conditions (e.g., temporal isolation vs. forced desychrony). We studied 94 subjects free-running through an ultradian LD cycle, which was a forced desychrony with a day length of 4 h (2.5 h awake in dim light, ~35 lux, alternating with 1.5 h for sleep in darkness). Circadian phase assessments were conducted before (baseline) and after (final) three 24-h days of the ultradian LD cycle. During these assessments, saliva samples were collected every 30 min and subsequently analyzed for melatonin. The phase shift of the dim light melatonin onset (DLMO) from baseline to final phase assessment gave the free-running period. The mean ± SD period was 24.31 ± .23 h and ranged from 23.7 to 24.9 h. Black subjects had a significantly shorter free-running period than Whites (24.18 ± .23 h, N =20 vs. 24.37 ± .22 h, N = 55). We had a greater proportion of women than men in our Black sample, so to check the τ difference we compared the Black women to White women. Again, Black subjects had a significantly shorter free-running period (24.18 ± .23, N = 17 vs. 24.41 ± .23, N = 23). We did not find any sex differences in the free-running period. These findings give rise to several testable predictions: on average, Blacks should adapt quicker to eastward flights across time zones than Whites, whereas Whites should adjust quicker to westward flights than Blacks. Also, Blacks should have more difficulty adjusting to night-shift work and day sleep, which requires a phase delay. On the other hand, Whites should be more likely to have trouble adapting to the early work and school schedules imposed by society. More research is needed to confirm these results and predictions.

Shift work: health, performance and safety problems, traditional countermeasures, and innovative management strategies to reduce circadian misalignment.

There are three mechanisms that may contribute to the health, performance, and safety problems associated with night-shift work: (1) circadian misalignment between the internal circadian clock and activities such as work, sleep, and eating, (2) chronic, partial sleep deprivation, and (3) melatonin suppression by light at night. The typical countermeasures, such as caffeine, naps, and melatonin (for its sleep-promoting effect), along with education about sleep and circadian rhythms, are the components of most fatigue risk-management plans. We contend that these, while better than nothing, are not enough because they do not address the underlying cause of the problems, which is circadian misalignment. We explain how to reset (phase-shift) the circadian clock to partially align with the night-work, day-sleep schedule, and thus reduce circadian misalignment while preserving sleep and functioning on days off. This involves controlling light and dark using outdoor light exposure, sunglasses, sleep in the dark, and a little bright light during night work. We present a diagram of a sleep-and-light schedule to reduce circadian misalignment in permanent night work, or a rotation between evenings and nights, and give practical advice on how to implement this type of plan.

Quantitative colorimetric assay for total protein applied to the red wine Pinot noir.

A standard method for assaying protein in red wine is currently lacking. The method described here is based on protein precipitation followed by dye binding quantification. Improvements over existing approaches include minimal sample processing prior to protein precipitation with cold trichloroacetic acid/acetone and quantification based on absorbance relative to a commercially available standard representative of proteins likely to be found in wine, the yeast mannoprotein invertase. The precipitation method shortened preparation time relative to currently published methods and the mannoprotein standard yielded values comparable to those obtained by micro-Kjeldahl analysis. The assay was used to measure protein in 48 Pinot noir wines from 6 to 32 years old. The protein content of these wines was found to range from 50 to 102 mg/L with a mean value of 70 mg/L. The availability of a simple and relatively rapid procedure for assaying protein provides a practical tool to quantify a wine component that has been overlooked in routine analyses of red wines.

Characterisation of transmission Raman spectroscopy for rapid quantitative analysis of intact multi-component pharmaceutical capsules.

A detailed characterisation of the performance of transmission Raman spectroscopy was performed from the standpoint of rapid quantitative analysis of pharmaceutical capsules using production relevant formulations comprising of active pharmaceutical ingredient (API) and 3 common pharmaceutical excipients. This research builds on our earlier studies that identified the unique benefits of transmission Raman spectroscopy compared to conventional Raman spectroscopy. These include the ability to provide bulk information of the content of capsules, thus avoiding the sub-sampling problem, and the suppression of interference from the capsule shell. This study demonstrates, for the first time, the technique's insensitivity to the amount of material held within the capsules. Different capsules sizes with different overall fill weights (100-400 mg) and capsule shell colours were assayed with a single calibration model developed using only one weight and size sample set (100 mg) to a relative error of typically <3%. The relative root mean square error of prediction of the concentration of API for the main sample set (nominal content 75%, w/w) was 1.5% with a 5s acquisition time. Models built using the same calibration set also predicted the 3 low level excipients with relative errors of 5-15%. The quantity of API was also predicted (with a relative error within ∼3%) using the same model for capsules prepared with different generations of API (i.e. API manufactured via different processes). The study provides further foundation blocks for the establishment of this emerging technique as a routine pharmaceutical analysis tool, capitalising on the inherently high chemical specificity of Raman spectroscopy and the non-invasive nature of the measurement. Ultimately, this technique has significant promise as a Process Analytical Technology (PAT) tool for online production application.

A compromise circadian phase position for permanent night work improves mood, fatigue, and performance.

STUDY OBJECTIVE: To assess night shift improvements in mood, fatigue, and performance when the misalignment between circadian rhythms and a night shift, day sleep schedule is reduced. DESIGN: Blocks of simulated night shifts alternated with days off. Experimental subjects had interventions to delay their circadian clocks to partially align with a night shift schedule. Control subjects had no interventions. Subjects were categorized according to the degree of circadian realignment independent of whether they were in the experimental or control groups. Twelve subjects were categorized as not re-entrained, 21 as partially re-entrained, and 6 as completely re-entrained. SETTING: Home sleep and laboratory night shifts. PARTICIPANTS: Young healthy adults. INTERVENTIONS: Experimental subjects had intermittent bright light pulses during night shifts, wore dark sunglasses outside, and had scheduled sleep episodes in darkness. MEASUREMENTS AND RESULTS: A computerized test battery was administered every 2 hours during day and night shifts. After about one week on the night shift schedule, which included a weekend off, the partially and completely re-entrained groups had markedly improved mood, fatigue, and performance compared to the group that was not re-entrained. The completely and partially re-entrained groups were similar to each other and had levels of mood, fatigue, and performance that were close to daytime levels. CONCLUSIONS: Partial re-entrainment to a permanent night shift schedule, which can be produced by feasible, inexpensive interventions, is associated with greatly reduced impairments during night shifts.

Racial differences in the human endogenous circadian period.

The length of the endogenous period of the human circadian clock (tau) is slightly greater than 24 hours. There are individual differences in tau, which influence the phase angle of entrainment to the light/dark (LD) cycle, and in doing so contribute to morningness-eveningness. We have recently reported that tau measured in subjects living on an ultradian LD cycle averaged 24.2 hours, and is similar to tau measured using different experimental methods. Here we report racial differences in tau. Subjects lived on an ultradian LD cycle (1.5 hours sleep, 2.5 hours wake) for 3 days. Circadian phase assessments were conducted before and after the ultradian days to determine the change in circadian phase, which was attributed to tau. African American subjects had a significantly shorter tau than subjects of other races. We also tested for racial differences in our previous circadian phase advancing and phase delaying studies. In the phase advancing study, subjects underwent 4 days of a gradually advancing sleep schedule combined with a bright light pulse upon awakening each morning. In the phase delaying study, subjects underwent 4 days of a gradually delaying sleep schedule combined with evening light pulses before bedtime. African American subjects had larger phase advances and smaller phase delays, relative to Caucasian subjects. The racial differences in tau and circadian phase shifting have important implications for understanding normal phase differences between individuals, for developing solutions to the problems of jet lag and shift work, and for the diagnosis and treatment of circadian rhythm based sleep disorders such as advanced and delayed sleep phase disorder.

Phase delaying the human circadian clock with a single light pulse and moderate delay of the sleep/dark episode: no influence of iris color.

BACKGROUND: Light exposure in the late evening and nighttime and a delay of the sleep/dark episode can phase delay the circadian clock. This study assessed the size of the phase delay produced by a single light pulse combined with a moderate delay of the sleep/dark episode for one day. Because iris color or race has been reported to influence light-induced melatonin suppression, and we have recently reported racial differences in free-running circadian period and circadian phase shifting in response to light pulses, we also tested for differences in the magnitude of the phase delay in subjects with blue and brown irises. METHODS: Subjects (blue-eyed n = 7; brown eyed n = 6) maintained a regular sleep schedule for 1 week before coming to the laboratory for a baseline phase assessment, during which saliva was collected every 30 minutes to determine the time of the dim light melatonin onset (DLMO). Immediately following the baseline phase assessment, which ended 2 hours after baseline bedtime, subjects received a 2-hour bright light pulse (~4,000 lux). An 8-hour sleep episode followed the light pulse (i.e. was delayed 4 hours from baseline). A final phase assessment was conducted the subsequent night to determine the phase shift of the DLMO from the baseline to final phase assessment.Phase delays of the DLMO were compared in subjects with blue and brown irises. Iris color was also quantified from photographs using the three dimensions of red-green-blue color axes, as well as a lightness scale. These variables were correlated with phase shift of the DLMO, with the hypothesis that subjects with lighter irises would have larger phase delays. RESULTS: The average phase delay of the DLMO was -1.3 +/- 0.6 h, with a maximum delay of ~2 hours, and was similar for subjects with blue and brown irises. There were no significant correlations between any of the iris color variables and the magnitude of the phase delay. CONCLUSION: A single 2-hour bright light pulse combined with a moderate delay of the sleep/dark episode delayed the circadian clock an average of ~1.5 hours. There was no evidence that iris color influenced the magnitude of the phase shift. Future studies are needed to replicate our findings that iris color does not impact the magnitude of light-induced circadian phase shifts, and that the previously reported differences may be due to race.

Phase delaying the human circadian clock with blue-enriched polychromatic light.

The human circadian system is maximally sensitive to short-wavelength (blue) light. In a previous study we found no difference between the magnitude of phase advances produced by bright white versus bright blue-enriched light using light boxes in a practical protocol that could be used in the real world. Since the spectral sensitivity of the circadian system may vary with a circadian rhythm, we tested whether the results of our recent phase-advancing study hold true for phase delays. In a within-subjects counterbalanced design, this study tested whether bright blue-enriched polychromatic light (17000 K, 4000 lux) could produce larger phase delays than bright white light (4100 K, 5000 lux) of equal photon density (4.2x10(15) photons/cm(2)/sec). Healthy young subjects (n = 13) received a 2 h phase delaying light pulse before bedtime combined with a gradually delaying sleep/dark schedule on each of 4 consecutive treatment days. On the first treatment day the light pulse began 3 h after the dim light melatonin onset (DLMO). An 8 h sleep episode began at the end of the light pulse. Light treatment and the sleep schedule were delayed 2 h on each subsequent treatment day. A circadian phase assessment was conducted before and after the series of light treatment days to determine the time of the DLMO and DLMOff. Phase delays in the blue-enriched and white conditions were not significantly different (DLMO: -4.45+/-2.02 versus -4.48+/-1.97 h; DLMOff: -3.90+/-1.97 versus -4.35+/-2.39 h, respectively). These results indicate that at light levels commonly used for circadian phase shifting, blue-enriched polychromatic light is no more effective than the white polychromatic lamps of a lower correlated color temperature (CCT) for phase delaying the circadian clock.

Practical interventions to promote circadian adaptation to permanent night shift work: study 4.

Scheduled bright light and darkness can phase shift the circadian clocks of night workers for complete adaptation to a night work, day sleep schedule, but few night workers would want this because it would leave them out of phase with the diurnal world on days off. This is the final study in a series designed to produce a compromise circadian phase position for permanent night shift work in which the sleepiest circadian time is delayed out of the night work period and into the first half of the day sleep episode. The target compromise phase position was a dim light melatonin onset (DLMO) of 3:00, which puts the sleepiest circadian time at approximately 10:00. This was predicted to improve night shift alertness and performance while permitting sufficient daytime sleep after work as well as late-night sleep on days off. In a between-subjects design, 19 healthy subjects underwent 3 simulated night shifts (23:00-7:00), 2 days off, 4 more night shifts, and 2 more days off. Subjects "worked" in the lab and slept at home. Experimental subjects received four 15-min bright light pulses during each night shift, wore dark sunglasses when outside, slept in dark bedrooms at scheduled times, and received outdoor afternoon light exposure ("light brake") to keep their rhythms from delaying too far. Control subjects remained in normal room light during night shifts, wore lighter sunglasses, and had unrestricted sleep and outdoor light exposure. The final DLMO of the experimental group was 3:22 +/- 2.0 h, close to the target of 3:00, and later than the control group at 23:24 +/- 3.8 h. Experimental subjects slept for nearly all the permitted time in bed. Some control subjects who slept late on weekends also reached the compromise phase position and obtained more daytime sleep. Subjects who phase delayed (whether in the experimental or control group) close to the target phase performed better during night shifts. A compromise circadian phase position improved performance during night shifts, allowed sufficient sleep during the daytime after night shifts and during the late nighttime on days off, and can be produced by inexpensive and feasible interventions.

Phase advancing the human circadian clock with blue-enriched polychromatic light.

BACKGROUND: Previous studies have shown that the human circadian system is maximally sensitive to short-wavelength (blue) light. Whether this sensitivity can be utilized to increase the size of phase shifts using light boxes and protocols designed for practical settings is not known. We assessed whether bright polychromatic lamps enriched in the short-wavelength portion of the visible light spectrum could produce larger phase advances than standard bright white lamps. METHODS: Twenty-two healthy young adults received either a bright white or bright blue-enriched 2-h phase advancing light pulse upon awakening on each of four treatment days. On the first treatment day the light pulse began 8h after the dim light melatonin onset (DLMO), on average about 2h before baseline wake time. On each subsequent day, light treatment began 1h earlier than the previous day, and the sleep schedule was also advanced. RESULTS: Phase advances of the DLMO for the blue-enriched (92+/-78 min, n=12) and white groups (76+/-45 min, n=10) were not significantly different. CONCLUSION: Bright blue-enriched polychromatic light is no more effective than standard bright light therapy for phase advancing circadian rhythms at commonly used therapeutic light levels.

Night shift performance is improved by a compromise circadian phase position: study 3. Circadian phase after 7 night shifts with an intervening weekend off.

STUDY OBJECTIVE: To produce a compromise circadian phase position for permanent night shift work in which the sleepiest circadian time is delayed out of the night work period and into the first half of the day sleep period. This is predicted to improve night shift alertness and performance while permitting adequate late night sleep on days off. DESIGN: Between-subjects. SETTING: Home and laboratory. PARTICIPANTS: 24 healthy subjects. INTERVENTIONS: Subjects underwent 3 simulated night shifts, 2 days off, and 4 more night shifts. Experimental subjects received five, 15 minute bright light pulses from light boxes during night shifts, wore dark sunglasses when outside, slept in dark bedrooms at scheduled times after night shifts and on days off, and received outdoor afternoon light exposure (the "light brake"). Control subjects remained in normal room light during night shifts, wore lighter sunglasses, and had unrestricted sleep and outdoor light exposure. MEASUREMENTS AND RESULTS: The final dim light melatonin onset (DLMO) of the experimental group was approximately approximately 04:30, close to our target compromise phase position, and significantly later than the control group at approximately 00:30. Experimental subjects performed better than controls, and slept for nearly all of the allotted time in bed. By the last night shift, they performed almost as well during the night as during daytime baseline. Controls demonstrated pronounced performance impairments late in the night shifts, and exhibited large individual differences in sleep duration. CONCLUSIONS: Relatively inexpensive and feasible interventions can produce adaptation to night shift work while still allowing adequate nighttime sleep on days off.

Shaping the light/dark pattern for circadian adaptation to night shift work.

This is the second in a series of simulated night shift studies designed to achieve and subsequently maintain a compromise circadian phase position between complete entrainment to the daytime sleep period and no phase shift at all. We predict that this compromise will yield improved night shift alertness and daytime sleep, while still permitting adequate late night sleep and daytime wakefulness on days off. Our goal is to delay the dim light melatonin onset (DLMO) from its baseline phase of approximately 21:00 to our target of approximately 3:00. Healthy young subjects (n=31) underwent three night shifts followed by two days off. Two experimental groups received intermittent bright light pulses during night shifts (total durations of 75 and 120 min per night shift), wore dark sunglasses when outside, slept in dark bedrooms at scheduled times after night shifts and on days off, and received outdoor light exposure upon awakening from sleep. A control group remained in dim room light during night shifts, wore lighter sunglasses, and had unrestricted sleep and outdoor light exposure. After the days off, the DLMO of the experimental groups was approximately 00:00-1:00, not quite at the target of 3:00, but in a good position to reach the target after subsequent night shifts with bright light. The DLMO of the control group changed little from baseline. Experimental subjects performed better than control subjects during night shifts on a reaction time task. Subsequent studies will reveal whether the target phase is achieved and maintained through more alternations of night shifts and days off.

Non-invasive quantitative assessment of the content of pharmaceutical capsules using transmission Raman spectroscopy.

This study demonstrates how transmission Raman spectroscopy can be used in the quantitative, non-invasive probing of the bulk content of production line relevant pharmaceutical products contained within capsules with a strong interfering Raman signal (principally TiO(2)). This approach is particularly beneficial in situations where the conventional Raman backscattering method is hampered or fails due to excessive Raman or fluorescence signals emanating from surface layers (capsule or coating) that pollute the much weaker subsurface Raman signals. In these feasibility experiments the interfering surface Raman signal was effectively suppressed, relative to the Raman signal of the internal content, by a factor of 33, in the transmission geometry in comparison with the conventional backscattering Raman approach. In conjunction with the superior bulk probing ability of the transmission Raman geometry, which effectively removes the sub-sampling problem inherent to conventional Raman spectroscopy, and multivariate analysis (principal component analysis (PCA), partial least squares (PLS) and classical least squares (CLS) regression), this provides an analytical tool well suited for rapid control monitoring applications in the pharmaceutical industry. The measured relative root mean square error of prediction (RMSEP) of the concentration of the active pharmaceutical ingredient (API) was 1.2 and 1.8% with 5 and 1s acquisition times, respectively.