Extending a Model of Shift‐Work Tolerance

The present study contributes to theory and practice through the development of a model of shift‐work tolerance with the potential to indicate interventions that reduce nurses' intention toward turnover and increase job satisfaction in hospital‐based settings. Survey data from 1257 nurses were used to conduct structural equation modeling that examine the direct and indirect effects of supervisor and colleague support, team identity, team climate, and control over working environment on time‐based work/life conflict, psychological well‐being, physical symptoms, job satisfaction, and turnover intention. The analysis of the proposed model revealed a good fit The chi‐square difference test was non‐significant (χ²(26)=338.56), the fit indices were high (CFI=.923, NFI=.918, and NNFI=.868), the distribution of residuals was symmetric and approached zero, the average standardized residual was low (AASR=.04), and the standardized RMR was. 072. In terms of the predictor variable, the final model explained 48% of the variance in turnover intention. The data revealed considerable evidence of both direct effects on adjustment and complex indirect links between levels of adjustment and work‐related social support, team identity, team climate, and control. Nurses with high supervisor and coworker support experienced more positive team climates, identified more strongly with their team, and increased their perceptions of control over their work environment. This in turn lowered their appraisals of their time‐based work/life conflict, which consequently increased their psychological well‐being and job satisfaction and reduced their physical health symptoms and turnover intention. The type of shift schedule worked by the nurses influenced levels of turnover intention, control over work environment, time‐based work/life conflict, and physical symptoms.     

Vapour-Liquid Phase Equilibria of n-alkanes by Direct Monte Carlo Simulations

Abstract

We report results of direct Monte Carlo simulations of n-pentane and n-decane at the liquidvapour interface for a number of temperatures. The intermolecular interactions are modeled using the last version of the anisotropic united atom model (AUA4). We have used the local long range correction energy and an algorithm allowing to select randomly with equal probability two different displacements. The liquid and vapour densities are in excellent agreement with experimental data and with those previously calculated using the GEMC method.     

Spatial summation in the tactile sensory system: Probability summation and neural integration

Psychophysical thresholds for the detection of a 300-Hz burst of vibration applied to the thenar eminence were measured for stimuli applied to the skin through 1.5?cm² and through 0.05?cm² contactors. Thresholds were approximately 13?dB lower when the area of the contactor was 1.5?cm² than when it was 0.05?cm². The difference between the thresholds measured with the large and small contactors was significantly reduced when only the lowest thresholds obtained in the testing sessions were considered. This result supports the hypothesis that one component of spatial summation in the P channel is probability summation. In addition, threshold measurements within a session were less variable when measured with the 1.5?cm² contactor. We conclude that spatial summation in the P channel is a joint function of two processes that occur as the areal extent of the stimulus increases: probability summation in which the probability of exceeding the psychophysical detection threshold increases as the number of receptors of varying sensitivities increases, and neural integration in which neural activity originating from separate receptors is combined within the central nervous system rendering the channel more sensitive to the stimulus.     

Contingent absences account for range limits but not the local abundance structure of an invasive springtail

Understanding spatial variation in abundance is essential for forecasts of responses to environmental change impacts on diversity and the consequent conservation actions. However, few studies have sought to distinguish the causal basis of abundance structure and range limits. Here we do so for an invasive springtail species, Pogonognathellus flavescens, in a cold temperate island setting. Local microclimate variables and physiological tolerances of this habitat generalist suggest that it should be widely distributed across a range of habitats below 200 m elevation on the island. By contrast, island‐wide and local abundance surveys show that it is restricted to indigenous Poa cookii tussock grassland habitats in the southeast. Preference for this habitat is correlated with the presence of vertebrates and a threshold response to soil Ca and pH, with preference for low values of both. Habitat specificity may be the consequence of a founder effect because the species is characterized by only a single mitochondrial COI haplotype. Nonetheless, P. flavescens is absent from many other areas of suitable P. cookii habitat around the island. The most plausible explanation appears to be dispersal limitation (i.e. a contingent absence). Despite high locomotion speeds measured in the laboratory at optimum and mean annual soil temperatures (0.97 and 0.42 cm s^?1 at 26°C and 6.5°C, respectively), dispersal in the field indicated that >100 yr would be required to reach all available habitat in the absence of jump dispersal, for which few vectors exist. Thus, current range limits are set by dispersal limitation (i.e. contingent absences) whilst abundance structure is a function of variation in soil substrate quality. Edaphic variables both in this species and other soil invertebrates may be more significant than climatic factors in determining abundance and occurrence, indicating that they should be routinely included in species distribution models. Low genetic diversity and high habitat preference suggest that in the absence of introduction of additional individuals, the species will not spread rapidly at the island. However, over time, the widening distribution of its preferred habitat, P. cookii, as a consequence of a major management intervention (the eradication of feral cats), may enable it to colonize all suitable areas.     

Eumelanin‐based colouration reflects local survival of juvenile feral pigeons in an urban pigeon house

Urbanisation introduces deep changes in habitats, eventually creating new urban ecosystems where ecological functions are driven by human activities. The higher frequency of some phenotypes in urban vs rural/wild areas has led to the assumption that directional selection in urban habitats occurs, which may thereby favour some behavioural and physiological traits in urban animal populations compared to rural ones. However, empirical evidence of directional selection on phenotypic traits in urban areas remains scarce. In this study we tested whether eumelanin‐based colouration could be linked to survival in two urban populations of the feral pigeon Columba livia. A number of studies in different cities pointed out a higher frequency of darker individuals in more urbanised areas compared to rural ones. To investigate whether directional selection through survival on this highly heritable trait could explain such patterns, we conducted mark–recapture studies on two populations of feral pigeons in highly urbanized areas. We predicted that darker coloured individuals would exhibit higher survival and/or philopatry (integrated into ‘local survival’) than paler coloured ones. No difference in local survival was found between adults of different colouration intensities. However, on one site, we found that darker juveniles had a higher local survival probability than light ones. Juvenile local survival on that site was also negatively correlated with the number of chicks born. This suggests the existence of colour‐ and/or density‐dependent selection processes acting on juvenile feral pigeons in urban environments, acting through differential mortality and/or dispersal.     

Seasonal Variation in Human Salivary Cortisol Concentration

Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month‐to‐month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time‐of‐day (4 levels) as categorical predictors. Cortisol concentrations were analyzed on a log scale. The diurnal pattern of cortisol was similar across months (interaction between month and time of day: p>0.4). The main effects of month and time‐of‐day were statistically significant (p <0.001). Highest concentrations were observed in February, March, and April, and lowest concentrations were observed in July and August. There were no statistically significant effects in any of the other measures, or between men and women. In conclusion, a seasonal variation in salivary cortisol concentrations was detected in an occupationally active population. Thus, seasonal variation needs to be taken into account when designing and evaluating field studies and interventions and when making comparisons across studies.     

UVC fluencies for preventative treatment of Pseudomonas aeruginosa contaminated polymer tubes

Exposing Pseudomonas aeruginosa biofilm grown on the inner surface of Teflon and silicone tubes to UVC light (265 nm) from light emitting diodes (LED) has previously been shown to substantially reduce biofilm growth. Smaller UVC fluencies were required to disinfect Teflon tubes compared to silicone tubes. Light propagation enhancement in tubes can be obtained if the refractive index of the intra-luminal saline solution is higher than that of the polymer. This condition is achieved by using Teflon tubes with a low refractive index (1.34) instead of the polymers with a high refractive index (1.40–1.50) normally used for tubing in catheter production. Determining whether or not UVC light exposure can disinfect and maintain the intra-luminal number of colony forming units (CFUs) at an exceedingly low level and thus avoid the growth and establishment of biofilm is of interest. The use of UVC diodes is demonstrated to be a preventative disinfection treatment on tubes made of Teflon, which enhances the UVC light propagation, and on tubes made of a softer material, ethylene vinyl acetate (EVA), which is suitable for catheters but much less suitable for UVC light propagation. Simulating an aseptic breach (～10³–10⁴ CFU ml^?1), the UVC disinfection set-up was demonstrated using tubes contaminated with planktonic P. aeruginosa. After the tubes (10–20 cm) were inoculated with the bacterial solution for 3 h, they were emptied and filled with saline solutions (0.9–20%). Next UVC fluencies (0–21 mJ cm^?2) were applied to the tubes 3 h after inoculation. Colony counts were carried out on liquid samples drawn from the tubes the first day after UVC treatment and liquid and surface samples were collected and analyzed 3–4 days later. A fluence of approximately 1.0 mJ cm^?2 was noted as being sufficient for no growth for a period of 3–4 days for the Teflon tubes. Determining the fluence threshold for the EVA tubes was not possible. Almost all of the UVC-treated EVA tubes were disinfected simply by filling the tubes with a saline solution. Direct UVC treatment of the contaminated EVA tubes revealed, however, that a fluence of 21 mJ cm^?2 killed the bacteria present in the tubes and kept them disinfected for a period of 3–4 days.     

Design,synthesis and biological evaluation of novel aminothiazoles as antiviral compounds acting against human rhinovirus

We describe here the design, synthesis and biological evaluation of antiviral compounds acting against human rhinovirus (HRV). A series of aminothiazoles demonstrated pan-activity against the HRV genotypes screened and productive structure–activity relationships. A comprehensive investigational library was designed and performed allowing the identification of potent compounds with lower molecular weight and improved ADME profile. 31d-1, 31d-2, 31f showed good exposures in CD-1 mice. The mechanism of action was discovered to be a host target: the lipid kinase phosphatidylinositol 4-kinase III beta (PI4KIIIß). The identification of the pan-HRV active compound 31f combined with a structurally distinct literature compound T-00127-HEV1 allowed the assessment of target related tolerability of inhibiting this kinase for a short period of time in order to prevent HRV replication.     

Structure–activity relationships of 6-(aminomethylphenoxy)-benzoxaborole derivatives as anti-inflammatory agent

A series of novel 6-(aminomethylphenoxy)benzoxaborole analogs was synthesized for the investigation of the structure–activity relationship of the inhibition of TNF-alpha, IL-1beta, and IL-6, from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compounds 9d and 9e showed potent activity against all three cytokines with IC₅₀ values between 33 and 83 nM. Chloro substituted analog 9e (AN3485) is considered to be a promising lead for novel anti-inflammatory agent with a favorable pharmacokinetic profile.     

Discovery and structure–activity relationships of 6-(benzoylamino)benzoxaboroles as orally active anti-inflammatory agents

Structure–activity relationships of 6-(benzoylamino)benzoxaborole analogs were investigated for the inhibition of TNF-α, IL-1β, and IL-6 from lipopolysaccharide stimulated peripheral blood mononuclear cells. Compound 1q showed potent activity against all three cytokines with IC₅₀ values between 0.19 and 0.50 μM, inhibited LPS-induced TNF-α and IL-6 elevation in mice and improved collagen-induced arthritis in mice. Compound 1q (AN4161) is considered to be a promising lead for novel anti-inflammatory agent with an excellent pharmacokinetic profile.