Alertness and psychomotor performance levels of marine pilots on an irregular work roster

ABSTRACT

Fatigue is recognized as an important safety concern in the transportation industry. In this study, our goal was to investigate how circadian and sleep–wake dependent factors influence St-Lawrence River pilots’ sleep–wake cycle, alertness and psychomotor performance levels at work. A total of 18 male St-Lawrence River ship pilots were recruited to a 16–21-day field study. Pilots’ chronotype, sleepiness and insomnia levels were documented using standardized questionnaires. Their sleep–wake cycle was documented by a sleep–wake log and wrist-worn activity monitoring. Subjective alertness and objective psychomotor performances were assessed ~5×/day for each work and rest day. Ship transits were distributed throughout the 24-h day and lasted on average (± SEM) 5.93 ± 0.67 h. Main sleep periods occurred mainly at night, and objectively lasted 6.04 ± 1.02 h before work days. When going to bed at the end of work days, pilots subjectively reported sleeping 7.64 ± 1.64 h in the prior 24 h. Significant diurnal and wake-dependent effects were observed for subjective alertness and objective psychomotor performance, with minimum levels occurring between 09:00 and 10:00. Thus, despite their irregular work schedule, ship pilots presented, as a group, a diurnal variation of alertness and psychomotor performance indicative of a day-oriented circadian system. Important inter-individual differences were observed on psychomotor performance mesor and phase. In individuals, earlier phases in psychomotor performance were correlated with earlier chronotype. This study indicates that both circadian and homeostatic processes modulate alertness and psychomotor performance levels with worst levels reached when long shifts ended in the morning. This work has potential applications as it indicates fatigue countermeasures considering both processes are scientifically based.     

Comparative Study of Plasmonic Properties of Cysteine-Functionalized Gold and Silver Nanoparticle Aggregates

The absorptance spectra of gold and silver nanoparticle (NP) aqueous dispersions were measured by UV–visible spectroscopy and computed numerically by finite element method. Both NPs were functionalized by l-cysteine amino acid (Cys) in order to develop aggregate-based localized surface plasmon resonance biosensors. Absorptance spectra measured at an analogous pH value of ～4.9 were compared, where Au-Cys conjugates have moderately split spectra with two commensurate maxima, while Ag-Cys conjugates exhibit the most pronounced secondary peak according to the highest degree of aggregation. The purpose of our theoretical study was to determine the simplest linear chain-like and wavy aggregate geometries, which result in maxima matching the measured peaks. The aggregates were characterized by N number and d diameter of NPs, g gap between the NPs, and t thickness of the l-cysteine covering. By tuning the angle of incidence and E -field oscillation direction in p-polarized light with respect to the aggregates, the contribution of longitudinal and transversal modes was varied. The comparison of measurements and computations revealed that spectra measured on bioconjugate dispersions include effects of numerous aggregates with various geometries, illuminated from different directions and are influenced by inter-aggregate coupling. Inspecting the normalized E -field distribution surrounding the aggregates, it was shown that fundamentally different multipolar modes can be identified at primary and secondary absorptance maxima, due to coupled plasmonic resonances on NPs.     

Evaluating the Effectiveness of France’s Indoor Smoke-Free Law 1 Year and 5 Years after Implementation: Findings from the ITC France Survey

France implemented a comprehensive smoke-free law in two phases: Phase 1 (February 2007) banned smoking in workplaces, shopping centres, airports, train stations, hospitals, and schools; Phase 2 (January 2008) banned smoking in hospitality venues (bars, restaurants, hotels, casinos, nightclubs). This paper evaluates France’s smoke-free law based on the International Tobacco Control Policy Evaluation Project in France (the ITC France Project), which conducted a cohort survey of approximately 1,500 smokers and 500 non-smokers before the implementation of the laws (Wave 1) and two waves after the implementation (Waves 2 and 3). Results show that the smoke-free law led to a very significant and near-total elimination of observed smoking in key venues such as bars (from 94–97% to 4%) and restaurants (from 60–71% to 2–3%) at Wave 2, which was sustained four years later (6–8% in bars; 1–2% in restaurants). The reduction in self-reported smoking by smoking respondents was nearly identical to the effects shown in observed smoking. Observed smoking in workplaces declined significantly after the law (from 41–48% to 18–20%), which continued to decline at Wave 3 (to 14–15%). Support for the smoke-free laws increased significantly after their implementation and continued to increase at Wave 3 (p<.001 among smokers for bars and restaurants; p<.001 among smokers and p = .003 for non-smokers for workplaces). The findings demonstrate that smoke-free policies that are implemented in ways consistent with the Guidelines for Article 8 of the WHO Framework Convention on Tobacco Control (WHO FCTC) lead to substantial and sustained reductions in indoor smoking while also leading to high levels of support by the public. Moreover, contrary to arguments by opponents of smoke-free laws, smoking in the home did not increase after the law was implemented and prevalence of smoke-free homes among smokers increased from 23.2% before the law to 37.2% 5 years after the law.     

Crystal structure of lysine sulfonamide inhibitor reveals the displacement of the conserved flap water molecule in human immunodeficiency virus type 1 protease

Human immunodeficiency virus type 1 (HIV-1) protease has been continuously evolving and developing resistance to all of the protease inhibitors. This requires the development of new inhibitors that bind to the protease in a novel fashion. Most of the inhibitors that are on the market are peptidomimetics, where a conserved water molecule mediates hydrogen bonding interactions between the inhibitors and the flaps of the protease. Recently a new class of inhibitors, lysine sulfonamides, was developed to combat the resistant variants of HIV protease. Here we report the crystal structure of a lysine sulfonamide. This inhibitor binds to the active site of HIV-1 protease in a novel manner, displacing the conserved water and making extensive hydrogen bonds with every region of the active site.     

Biotic elicitor induced nitric oxide production in mitigation of Fusarium wilt of tomato

Journal of Plant Biochemistry and Biotechnology - The present study was performed to validate the efficacy of biotic elicitor (BE) on improving the innate immunity of tomato against Fusarium...     

A harvest framework for a recovering American black bear population

Having reproducible and transparent science-based processes in wildlife management ensures the integrity of decision making. These processes are particularly important when establishing harvest frameworks, as guiding information in the peer-reviewed literature is limited. We provide an example using multiple data sets, whose products guided aspects of the development of a harvest framework for a population of recolonizing American black bears (Ursus americanus) in Missouri, USA. To characterize the spatial distribution of harvest, we used 10 years (2010–2019) of black bear global positioning system (GPS) location data and 30 years (1991–2020) of sightings data to assess spatial vulnerability to harvest as the intersection among information on bear occurrence, bear sightings, and hunter land-use tendencies (i.e., the avoidance of steep slopes, large distances from roads). We then used the spatial vulnerability assessment, information on the distribution of public and private lands, and easily discernable boundaries (i.e., major highways, rivers) to suggest boundaries for bear management zones. Additionally, to identify the timing of harvest that would limit female harvest bias, we assessed the temporal vulnerability of harvest using sex-based changes in average daily step lengths and monthly utilization distribution sizes during fall. Black bear occurrence and sighting propensity was greater in southwestern Missouri, and potential hunter land use appeared pervasive across the landscape given the lack of landscape features that would disincentivize use. Given the influence of black bear occurrence and sighting propensity, spatial harvest vulnerability diminished from southern and southeastern to central portions of Missouri, with areas north of the Missouri River not a part of the established black bear range. We consequently divided areas south of the Missouri River into 3 black bear management zones: a small southwestern zone with primarily private lands and high harvest vulnerability, a southeastern zone that encompassed considerable public lands and moderate amounts of vulnerability, and a central zone that was composed mainly of areas of low vulnerability. Temporally, males did not exhibit movement-based changes, but females became less active after the first week of October and used 63.9% less area through fall. Based on movements rates of males and females, a hunting season after the first week of October could reduce the likelihood of females being harvested. Harvests from the black bear harvest season in 2021 suggest that the proportion of bears harvested in each zone was similar in distribution to the proportion of permits allocated across zones with no harvest sex bias, which was aligned with agency goals. Animal movement and space use data products can guide harvest framework decision-making.     

Induction of Adipocyte Differentiation by Polybrominated Diphenyl Ethers (PBDEs) in 3T3-L1 Cells

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants that were extensively used in commercial products. PBDEs are ubiquitous environmental contaminants that are both lipophilic and bioaccumulative. Effects of PBDEs on adipogenesis were studied in the 3T3-L1 preadipocyte cell model in the presence and absence of a known adipogenic agent, dexamethasone (DEX). A PBDE mixture designed to mimic body burden of North Americans was tested, in addition to the technical mixture DE-71 and the individual congener BDE-47. The mixture, DE-71, and BDE-47 all induced adipocyte differentiation as assessed by markers for terminal differentiation [fatty acid binding protein 4 (aP2) and perilipin] and lipid accumulation. Characterization of the differentiation process in response to PBDEs indicated that adipogenesis induced by a minimally effective dose of DEX was enhanced by these PBDEs. Moreover, C/EBPα, PPARγ, and LXRα were induced late in the differentiation process. Taken together, these data indicate that adipocyte differentiation is induced by PBDEs; they act in the absence of glucocorticoid and enhance glucocorticoid-mediated adipogenesis.     

A Century of Change in Kenya's Mammal Communities: Increased Richness and Decreased Uniqueness in Six Protected Areas

The potential for large-scale biodiversity losses as a result of climate change and human impact presents major challenges for ecology and conservation science. Governments around the world have established national parks and wildlife reserves to help protect biodiversity, but there are few studies on the long-term consequences of this strategy. We use Kenya as a case study to investigate species richness and other attributes of mammal communities in 6 protected areas over the past century. Museum records from African expeditions that comprehensively sampled mammals from these same areas in the early 1900''s provide a baseline for evaluating changes in species richness and community structure over time. We compare species lists assembled from archived specimens (1896–1950) to those of corresponding modern protected areas (1950–2013). Species richness in Kenya was stable or increased at 5 out of 6 sites from historical to modern times. Beta-diversity, in contrast, decreased across all sites. Potential biases such as variable historical vs. modern collection effort and detection of small-bodied, rare, and low-visibility species do not account for the observed results. We attribute the pattern of decreased beta diversity primarily to increased site occupancy by common species across all body size classes. Despite a decrease in land area available to wildlife, our data do not show the extinctions predicted by species-area relationships. Moreover, the results indicate that species-area curves based solely on protected areas could underestimate diversity because they do not account for mammal species whose ranges extend beyond protected area boundaries. We conclude that the 6 protected areas have been effective in preserving species richness in spite of continuing conversion of wild grasslands to cropland, but the overall decrease in beta diversity indicates a decline in the uniqueness of mammal communities that historically characterized Kenya''s varied landscape.     

Molecular Method for Detection of Total Coliforms in Drinking Water Samples

This work demonstrates the ability of a bacterial concentration and recovery procedure combined with three different PCR assays targeting the lacZ, wecG, and 16S rRNA genes, respectively, to detect the presence of total coliforms in 100-ml samples of potable water (presence/absence test). PCR assays were first compared to the culture-based Colilert and MI agar methods to determine their ability to detect 147 coliform strains representing 76 species of Enterobacteriaceae encountered in fecal and environmental settings. Results showed that 86 (58.5%) and 109 (74.1%) strains yielded a positive signal with Colilert and MI agar methods, respectively, whereas the lacZ, wecG, and 16S rRNA PCR assays detected 133 (90.5%), 111 (75.5%), and 146 (99.3%) of the 147 total coliform strains tested. These assays were then assessed by testing 122 well water samples collected in the Québec City region of Canada. Results showed that 97 (79.5%) of the samples tested by culture-based methods and 95 (77.9%), 82 (67.2%), and 98 (80.3%) of samples tested using PCR-based methods contained total coliforms, respectively. Consequently, despite the high genetic variability of the total coliform group, this study demonstrated that it is possible to use molecular assays to detect total coliforms in potable water: the 16S rRNA molecular assay was shown to be as efficient as recommended culture-based methods. This assay might be used in combination with an Escherichia coli molecular assay to assess drinking water quality.