Long‐term loads for a monopile‐supported offshore wind turbine

Accurate prediction of long‐term ‘characteristic’ loads associated with an ultimate limit state for design of a 5‐MW bottom‐supported offshore wind turbine is the focus of this study. Specifically, we focus on predicting the long‐term fore–aft tower bending moment at the mudline and the out‐of‐plane bending moment at the blade root of a monopile‐supported shallow‐water offshore wind turbine. We employ alternative probabilistic predictions of long‐term loads using inverse reliability procedures in establishing the characteristic loads for design. Because load variability depends on the environmental conditions (defining the wind speed and wave height), we show that long‐term predictions that explicitly account for such load variability are more accurate, especially for environmental states associated with above‐rated wind speeds and associated wave heights. Copyright © 2012 John Wiley & Sons, Ltd.     

Influence of Average Photon Energy index on solar irradiance characteristics and outdoor performance of photovoltaic modules

Solar spectral irradiance measurements on a routinely basis are relevant to study the influence of solar spectrum on the photovoltaic (PV) module performance, especially for thin film and third generation PV. Two spectroradiometers from EKO were added to the instrumentation available at the ESTER outdoor station of the University of Rome Tor Vergata. A detailed characterisation of the spectral irradiance at the site was carried on during more than 6 months of monitoring activity measuring spectral solar irradiance in the range 350–1700 nm with a time interval of 10 min on a horizontal plane. A wide variety of spectra were acquired in various weather conditions, and indications about the spectra behaviour on a daily and seasonal basis were obtained. Moreover, information about the effect of the weather conditions on the solar radiation spectral distribution were identified. The Average Photon Energy index was used as an indicator of the spectra characteristics. The same index was also used to evidence the solar spectrum influence on polycrystalline and double junction amorphous silicon PV modules. Copyright © 2012 John Wiley & Sons, Ltd.     

Posttraumatic stress disorder and retrospectively reported stressor exposure: A longitudinal prediction model.

There has been recent concern about the degree to which posttraumatic stress disorder (PTSD) symptomatology influences reports of prior exposure to highly stressful life events. In this longitudinal study of 2,942 male and female Gulf War veterans, the authors documented change in stressor reporting across 2 occasions and the association between change and PTSD symptom severity. A regression-based cross-lagged analysis was used to examine the relationship between PTSD symptom severity and later reported stressor exposure. Shifts in reporting over time were modestly associated with PTSD symptom severity. The cross-lagged analysis revealed a marginal association between Time 1 PTSD symptom severity and Time 2 reported stressor exposure for men and suggested that later reports of stressor exposure are primarily accounted for by earlier reports and less so by earlier PTSD symptomatology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Understanding the role of personality in explaining associations between marital quality and parenting.

Analyses assessed the degrees to which personality accounts for associations between marital quality and parenting and mediates genetic contributions to these relationships. Participants included 318 male and 544 female same-sex twin pairs from the Twin and Offspring Study in Sweden. All twins completed self-report measures of marital quality and personality (anxiousness, aggression, sociability). Composite measures of parent negativity and warmth were derived from the twins’ and their adolescent children’s ratings of the twins’ disciplinary styles and the emotional tone of the parent–child relationship. Observational ratings of marital quality and parenting were also obtained for a subset of twins. Personality characteristics explained 33% to 42% of the covariance between reported marital quality and parenting and 26% to 28% of the covariance between observed marital quality and parenting. For both sets of analyses, personality accounted for more than half of the genetic contributions to covariance between marital quality and parenting. Results indicate that personality significantly contributes to associations between marital quality and parenting and that personality is an important path through which genetic factors contribute to family relationships. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immune parameters in female workers exposed to urban pollutants

Urban outside workers, such as traffic police, are daily exposed to air pollutants and psychosocial stressors: for these workers, the working environment corresponds to the living environment of the general population. Studies in the literature have shown that immune parameters could be affected by chronic exposure to various chemical pollutants. The aim of this study is to evaluate whether occupational exposure to urban pollutants can cause alterations in NK, IL-2, IFN-gamma and C3 plasma levels in female traffic police compared to a control group. After excluding subjects with the principal confounding factors, 86 female traffic police and 87 controls were matched by age, years of police work and habitual alcohol consumption. The distribution of NK values in female traffic police and controls was significantly different (p=0.000); NK values above the upper limit of the normal laboratory range were observed in 23 female traffic police and in 2 controls (p=0.000). IL-2 mean levels were higher in traffic police compared to controls, but the difference was not significant. The mean and the distribution of IFN-gamma values in female traffic police and controls were not different. C3 mean levels were higher in female traffic police versus controls, but the difference was not significant. Considering that the subjects with the principal confounding factors were excluded from the study and that female traffic police and controls were matched by the above-mentioned variables, our results suggest that chronic occupational exposure to low doses of chemical stressors, which may interact with and add to psychosocial ones, can affect both innate and adaptative immunity.     

Improvement of Aspergillus niger Glucoamylase Thermostability by Directed Evolution

Directed evolution was used to improve the thermostability of Aspergillus niger glucoamylase (GA) expressed in Saccharomyces cerevisiae. A starch‐plate assay developed to screen GA mutants for thermostability gave results consistent with those of irreversible thermoinactivation kinetic analysis. Several thermostable multiply‐mutated GAs were isolated and characterized by DNA sequencing and kinetic analysis. Three new GA mutations, T62A, T290A and H391Y, have been identified that encode GAs that are more thermostable than wild‐type GA, and that improve thermostability cumulatively. These individual mutations were combined with the previously constructed thermostable site‐directed mutations D20C/A27C (forming a disulfide bond), S30P, and G137A to create a multiply‐mutated GA designated THS8. THS8 GA is substantially more thermostable than wild‐type GA at 80°C, with a 5.1 kJ/mol increase in the free energy of thermoinactivation, making it the most thermostable Aspergillus niger GA mutant characterized to date. THS8 GA and the singly‐mutated GAs have specific activities and catalytic efficiencies (k_cat/K_m) similar to those of wild‐type GA.     

Nonstarter lactobacilli isolated from soft and semihard Argentinean cheeses: genetic characterization and resistance to biological barriers

Nonstarter lactic acid bacteria isolated from Argentinean cheeses were identified and characterized by focusing on their resistance to biological barriers, along with other physiological features of potential interest, in the search for future probiotic organisms. Lactobacilli were enumerated and isolated from semihard and soft cheeses made with multistrain Streptococcus thermophilus starters. Lactobacilli counts in 1-week-old cheeses were between 10(5) and 10(7) CFU/g and then reached 10(7) CFU/ g in all 1-month samples, while streptococci were always above 10(9) CFU/g. A total number of 22 lactobacilli isolates were retained, identified, and characterized by in vitro tests. Species identity was determined by carbohydrate metabolism and species-specific PCR assays. Genetic diversity was explored by random amplified polymorphic DNA (RAPD) PCR analysis. The Lactobacillus strains were assigned to the species L. casei, L. plantarum, L. rhamnosus, L. curvatus, L. fermentum, and L. perolens. All the strains studied tolerated 25 ppm of lysozyme, and most of them showed resistance to 0.3% bile. After incubation in gastric solution (pH 2.0), counts decreased by several log units, ranging from 3.2 to 7.0. The strains were able to grow in the presence of bile salts, but only three isolates were capable of deconjugation. The nonstarter lactobacilli that were assayed fermented the prebiotic substrates (especially lactulose and inulin). Some strains showed high cell hydrophobicity and beta-galactosidase activity, as well as inhibitory activity against pathogenic bacteria. It was concluded that most of the lactobacilli isolated in this study demonstrated resistance to biological barriers and physiological characteristics compatible with probiotic properties, which make them suitable for further research in in vivo studies aimed at identifying new probiotic organisms.     

A microfluidic approach for development of hybrid collagen-chitosan extracellular matrix-like membranes for on-chip cell cultures

To advance organ-on-a-chip development and other areas befitting from physiologically-relevant biomembranes,a microfluidic platform is presented for synthesis of biomembranes during gelation and investigation into their role as extracellular matrix supports.In this work,high-throughput studies of collagen,chitosan,and collagen-chitosan hybrid biomembranes were carried out to characterize and compare key properties as a function of the applied hydrodynamic conditions during gelation.Specifically,depending on the biopolymer material used,varying flow conditions during biomembrane gelation caused width,uniformity,and swelling ratio to be differently affected and controllable.Finally,cell viability studies of seeded fibroblasts were conducted,thus showing the potential for biological applications.     

On‐Chip Magnetic Platform for Single‐Particle Manipulation with Integrated Electrical Feedback

Methods for the manipulation of single magnetic particles have become very interesting, in particular for in vitro biological studies. Most of these studies require an external microscope to provide the operator with feedback for controlling the particle motion, thus preventing the use of magnetic particles in high‐throughput experiments. In this paper, a simple and compact system with integrated electrical feedback is presented, implementing in the very same device both the manipulation and detection of the transit of single particles. The proposed platform is based on zig‐zag shaped magnetic nanostructures, where transverse magnetic domain walls are pinned at the corners and attract magnetic particles in suspension. By applying suitable external magnetic fields, the domain walls move to the nearest corner, thus causing the step by step displacement of the particles along the nanostructure. The very same structure is also employed for detecting the bead transit. Indeed, the presence of the magnetic particle in suspension over the domain wall affects the depinning field required for its displacement. This characteristic field can be monitored through anisotropic magnetoresistance measurements, thus implementing an integrated electrical feedback of the bead transit. In particular, the individual manipulation and detection of single 1‐μm sized beads is demonstrated.