Longitudinally assessed biological correlates of personality and psychosocial dynamics in new university students

Personality traits and psychosocial factors can be dynamic when measured longitudinally; the higher education setting may influence trait stability and change. Furthermore, biological processes may be linked to trait and psychosocial factor development; specifically, immune functioning may be indicative of higher levels of stress. This study examined longitudinal associations between personality traits and psychosocial factors in first year university students. In the first phase of the study, 68 undergraduate students (27 men and 41 women) completed personality and psychosocial measures at four times during their first year of university, and provided three saliva samples to measure salivary secretory immunoglobulin-A (slgA) to determine immune functioning. A second cohort of first-year students (n = 187; 62 men and 125 women) only completed the personality and psychosocial measures. Across both samples, all of the Big Five traits (Neuroticism (N), Extraversion (E), Openness (O), Agreeableness (A), and Conscientiousness (C)) demonstrated at least moderate rank-order stability; A and C showed small meanlevel increases between the beginning of the second semester and exam time; overall personality trends did not concur with previous findings. Data on academic performance was also gathered. Greater mean-level variability and less rank-order stability were observed with the psychosocial measures as the students' time at university increased. Salivary slgA levels changed over the course of the year, with times of higher stress (beginning of the university semester and exam time) correlating with lower mucosal immunity. Linear growth curve modeling was used to represent the longitudinal data; end of first-year exam marks were significantly predicted by most of the trait and general psychosocial factors but not the university-specific factors; slgA release rate models were not significant with the measures in the present study. These results demonstrate varying degrees of change and stability in personality traits and psychosocial factors during the first year of university that, taken together, does not impact academic outcomes when examined on a developmental scale through longitudinal measurements. Immune functioning was related to periods of stress independent of stress perception and changes in psychosocial factors related to changes in mucosal immunity. Modeling of traits and psychosocial factors with immune functioning provides new insights into biopsychosocial dynamics operating in university students. Future studies may benefit from this work which emphasizes how longitudinally assessed traits and psychosocial factors can be dynamic and are linked to immune functioning

Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75-min recovery. RT measures were generated from an ex-Gaussian distribution that yielded three predictors: mu-RT, sigma-RT, and tau-RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = −.009, SE = .005, p = .09) and diastolic (B = −.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = −.007, SE = .003, p = .03) and impaired vagal tone (B = −.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses

Spontaneous dehydrocoupling in peri-substituted phosphine-borane adducts

This work was financially supported by the EPSRC and COST action CM1302 SIPs.Bis(borane) adducts Acenap(PiPr2·BH3)(PRH·BH3) (Acenap = acenaphthene-5,6-diyl; 4a, R = Ph; 4b, R = ferrocenyl, Fc; 4c, R = H) were synthesised by the reaction of excess H3B·SMe2 with either phosphino-phosphonium salts [Acenap(PiPr2)(PR)]+Cl− (1a, R = Ph; 1b, R = Fc), or bis(phosphine) Acenap(PiPr2)(PH2) (3). Bis(borane) adducts 4a–c were found to undergo dihydrogen elimination at room temperature, this spontaneous catalyst-free phosphine-borane dehydrocoupling yields BH2 bridged species Acenap(PiPr2)(µ-BH2)(PR·BH3) (5a, R = Ph; 5b, R = Fc; 5c, R = H). Thermolysis of 5c results in loss of the terminal borane moiety to afford Acenap(PiPr2)(µ-BH2)(PH) (14). Single crystal X-ray structures of 3, 4b and 5a–c are reported.Publisher PDFPeer reviewe

Health literacy: impact on the health of HIV-infected individuals.

Health literacy is known to affect vulnerable communities such as persons living with HIV/AIDS. The purpose of this review was to provide a current summary of research on the impact of health literacy on the health of persons living with HIV/AIDS and to address future areas of need. Contemporary studies focused on expanding the reach of health literacy in HIV/AIDS to retention in HIV care, use of technology for assessing and intervening to improve health literacy, and health literacy across the globe, for example. A number of studies did not find health literacy to explain health behaviors whereas other studies supported such a relationship. Future issues relevant to health literacy in HIV/AIDS include the aging of the HIV population and associated comorbidities, studies to understand the role of health literacy in specific populations affected by HIV/AIDS, and the continued need to refine the definition and measurement of health literacy

Macrofauna-sized foraminifera in epibenthic sledge samples from five areas in the eastern Clarion-Clipperton Zone (equatorial Pacific)

Benthic foraminifera cannot be sampled adequately using a single device. Smaller taxa are best collected using multicorers, the larger with box corers, but towed devices (dredges, trawls and epibenthic sledges) also retain many larger species. Here, we describe macrofaunal (>300 µm) foraminiferal assemblages obtained using an epibenthic sledge (EBS) in the Clarion-Clipperton Zone (eastern equatorial Pacific), a region hosting seafloor deposits of polymetallic nodules. Twelve EBS samples were collected in four areas licenced for exploration by the International Seabed Authority (ISA) to German, IOM, Belgium and French contractors, and to APEI-3, one of the protected Areas of Special Scientific Interest designated by the ISA. We recognised 280 morphospecies among 1954 specimens, with between 74 (IOM) and 121 (Belgium) in particular areas. Most (92.7%) were single-chambered monothalamids, of which 75 species (26.8%) belonged to the Komokioidea (‘komoki’), 47 (16.8%) to branched and unbranched tubes, 33 (11.8%) to chain-like and 32 (11.4%) to various ‘komoki-like’ forms. Fragments of megafaunal xenophyophores represented 21 species (7.50%), including Spiculammina delicata, previously reported only from the Russian area. Rarefaction curves and sample coverage completeness curves suggest that only a fraction of the macrofaunal foraminiferal diversity had been sampled. The occurrence of 71.8% of species in 1-2 of the 12 samples and 84.9% in 1-3 of the samples was a likely result of substantial undersampling. Dissimilarity in species composition between areas was very high: 64.2% (German vs IOM area) to 86.9% (German area vs APEI-3). Similarity within a single area was quite low: 29.1% (German) to 45.1% (IOM). In multidimensional scaling (MDS) plots, the APEI-3 area was clearly distinct in terms of faunal composition from all other areas, the French area somewhat separated from the German, IOM and Belgium areas, with the German and IOM samples being the most similar. These patterns may reflect the geographical separation of the French and APEI-3 areas and their location in deeper, more oligotrophic waters. Our study demonstrates that EBS samples from the eastern CCZ are a rich source of novel foraminiferal taxa, particularly light, easily resuspended komoki, providing a valuable perspective on foraminiferal biodiversity

Residence Time Distribution of Glass Ballotini in Isothermal Swirling Flows in a Counter-Current Spray Drying Tower

The particle residence time in counter-current spray drying towers has a significant influence on the moisture content of the powder exiting the tower. Therefore, the reliability of predictions of residence time by numerical methods is highly desirable. A combined experimental and computational fluid dynamics investigation is reported for the prediction of the residence time distributions of glass beads with a narrow size range of 300-425 m in a counter-current tower with isothermal swirling flows of air. The particle-wall collision is taken into account using a rough-wall collision model. Overall, a reasonably good agreement is obtained between the measurements and predictions. Consideration of wall roughness results in greater axial dispersion of particles in the tower compared to a smooth wall assumption. The rough particle-wall collision is important for a reliable prediction of residence time distributions. In addition, analysis of the results infers that the clustering effect of particles on drag and particle-particle interactions are important and should be investigated in a future study

Particle aggregation in large counter-current spray drying towers: Nozzle configuration, vortex momentum and temperature

This work investigates particle growth in a counter-current swirl detergent dryer, operating with a single nozzle, at a range of nozzle heights, air drying temperatures, TA, and superficial air velocities, UA, which were selected to enhance or inhibit particle aggregation in the dryer. The growth kinetics are discussed paying special attention to the impact of the cycle of deposition and re-entrainment of material from the wall deposits. All cases lead to substantial aggregation and mono-modal product size distributions. The operation at low UA and high TA, (i.e. low momentum) does not inhibit growth as one would expect from a lower particle concentration and faster heat and mass transfer, conditions which would lead to less particle collisions resulting in growth. In contrast, generation of aggregated particles > 850 μm is promoted, suggesting that a change in the erosion behavior of particles from the wall due to a reduction in energy of particle impacts. As a result of lower stresses, erosion is suppressed and clusters remain at the wall for longer, what allows them to sinter and be re-entrained at larger sizes. In contrast, increasing the momentum of the continuous phase by operation at low TA and high UA inhibits particle growth, particularly in the production of the largest sizes > 850 μm. In this case the rate and energy of impacts to the wall increases, this leads to higher disruptive stresses on the wall deposits, thus, reducing the size of the clusters re-entrained. In summary, this work describes aggregation mechanisms in swirl detergent dryers operated with single nozzles, suggesting that, contrary to expectations, wearing of deposits rather than air-borne contacts may be a key contributor to the enhancement or inhibition of growth

CFD Simulation of a Counter-current Spray Drying Tower with Stochastic Treatment of Particle-wall Collision

In this study, a steady state, three-dimensional, multiphase CFD modeling of a pilot-plant counter-current spray drying tower is carried out to study the drying of detergent slurry and to predict spray-dried detergent powder characteristics. The coupling between the two phases is achieved using the Eulerian-Lagrangian approach. The continuous phase turbulence is modeled using the Reynolds stress transport model. The droplet drying kinetics is studied using a semi-empirical droplet/particle drying model. Emphasis is given on the modeling of particle-wall interaction by considering only the rebound effect and specifying the coefficient of restitution as a function of impact angle with wall surface roughness taken into account using a stochastic approach, as well as a function of moisture content. This influences the post-wall collision trajectories of particles, residence time distribution and the overall exchange of heat and mass transfer. The model predictions agree well with the measured outlet values of powder average temperature, moisture content and exhaust air temperature considering the complexity of the process and the measurements accuracy

Influence of wall friction on flow regimes and scale-up of counter-current swirl spray dryers

The structure of the vortex flow in swirl spray dryers is investigated after having fouled the walls with deposits typical of detergent manufacture. The range of Re and swirl intensity Ω characteristic of industry are studied using three counter-current units of varying scale and design. The friction with the deposits increases the flow turbulence kinetic energy and causes a drastic attenuation of the swirl and as a result, the vortex breaks down in the chamber forming recirculation regions (i.e. areas of reverse flow). Three flow regimes (1) no recirculation, (2) central and (3) annular recirculation have been identified depending on the swirl intensity. New control and scale up strategies are proposed for swirl dryers based in predicting the decay and the flow regime using the unit geometry (i.e. initial swirl intensity Ωi) and experimental decay rates function of the coverage and thickness of deposits. The impact in design and numerical modelling must be stressed. Adequate prediction of the swirl is vital to study fouling and recirculation, which surely play an important part in the dispersion and aggregation of the solid phase. Current models have no means to replicate these phenomena, and yet, in this case neglecting the deposits and assuming smooth walls would result in (a) over-prediction of swirl velocity up to 40-186% (b) under-prediction of turbulent kinetic energy up to 67-85% and (c) failure to recognise recirculation areas

An experimental investigation of the swirling flow in a tall-form counter current spray dryer

This work studies the air flow in a large swirl counter-current dryer using sonic anemometry. Air velocity and turbulence fields are reported at isothermal conditions and in the absence of particles. In a tall-form unit the structure of the flow is largely influenced by the design of the exit. A contraction originates a central jet and suppresses the formation of recirculation zones despite the vortex acquires a high swirl intensity Ω (i.e. 1<Ω<2). Access to a full scale tower has permitted to: (a) identify asymmetries owed to the design of inlet and exhaust ducts, (b) present the first detailed turbulence data in production units, characterized by a highly anisotropic field and the axial decay of the turbulence kinetic energy, (c) study the flow stability, identifying the precession of the vortex core and oscillations at a constant Strouhal number and (d) study the impact that a rough wall has in the strength of the swirl. This work presents the first clear evidence of significant friction in spray dryers. The swirl intensity Ω decays exponentially in the dryer at a rate between 0.08 and 0.09, much higher than expected in pipe flow and independent of Re in the range 105-2.2{dot operator}105. Production dryers have a large characteristic wall roughness due the presence of deposits, which explains the stronger friction and the discrepancies found in the past between data at full scale or clean laboratory or pilot scale units. It is essential to address this phenomenon in current numerical models, which are validated on laboratory or pilot scale facilities and ignore the role of deposits, thus causing an overprediction of the tangential velocity above 30-40%