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Polyurethane (PU) lacquer is a complex synthetic polymer. The mechanical properties of PU lacquers are influenced by the in-service environment, which may affect their function as protective coatings. As of date, limited research work has been published on the mechanical properties of PU lacquer films under environmental ageing conditions. This paper presents an investigation of the mechanical and hygroscopic behaviour of a commercial PU lacquer film. By means of water absorption and desorption tests, the diffusion coefficient and coefficient of hygroscopic expansion were determined. Tensile tests at constant displacement rates and creep tests under various UV/humidity ageing conditions showed a complex dependence of material properties on environmental conditions. A modified Burgers model with environment-dependent parameters is shown to satisfactorily model the mechanical behaviour of the PU lacquer in typical service conditions. [ABSTRACT FROM AUTHOR]

An experiment to measure granular temperature in a sheared low density granular bed containing a range of sizes of particles has been performed. Using positron emission particle tracking, a single particle was tracked from different size phases. From the coordinate data, the second moment of the velocity fluctuations about the mean flow in each direction was determined. It was found that the larger particles are 'hotter' and that most of the energy is contained in the θ (shearing) direction fluctuations. Evidence was found for Knudsen layer and higher order Burnett effects, suggesting extensions of the Navier-Stokes approaches are necessary to describe heat transport in polydisperse systems. [ABSTRACT FROM AUTHOR]

Within the framework of a Boltzmann-Lorentz equation, we analyze the dynamics of a granular rotor immersed in a bath of thermalized particles in the presence of a frictional torque on the axis. In numerical simulations of the equation, we observe two scaling regimes at low and high bath temperatures. In the large friction limit, we obtain the exact solution of a model corresponding to asymptotic behavior of the Boltzmann-Lorentz equation. In the limit of large rotor mass and small friction, we derive a Fokker- Planck equation for which the exact solution is also obtained. [ABSTRACT FROM AUTHOR]

Background:There are limited data concerning the relationships between changes in adipocytokines and cardiovascular disease (CVD) risk factors.Objective:To examine the longitudinal associations between leptin, adiponectin, resistin and ghrelin levels and CVD risk factor levels in women at midlife.Design:Prospective, observational study.Subjects and measurements:Leptin, adiponectin, resistin, ghrelin levels and CVD risk factors were measured in specimens collected from 40 women at 3 points in time corresponding to the pre-, peri- and postmenopause stages of their natural menopause transition.Results:In longitudinal analyses adjusted for CVD risk factors and leptin at the previous menopausal stage, aging, education, smoking and physical activity, greater increases in leptin over the menopause transition were associated with greater decreases in high-density lipoprotein cholesterol (HDL-c) and greater increases in diastolic blood pressure, glucose, insulin and insulin resistance (all P<0.05). Larger decreases in adiponectin over the menopause transition were associated with greater increases in systolic blood pressure, insulin and insulin resistance and with greater decreases in HDL-c. Greater increases in ghrelin levels over the menopausal transition were associated with greater low-density lipoprotein cholesterol increases (P=0.014). Resistin was not associated with CVD risk factor changes.Conclusion:There were significant adverse associations of adipocytokines and ghrelin with multiple CVD risk factor changes in women across midlife. Given that this time period is dynamic for CVD risk, these data underscore the need for additional prospective studies.International Journal of Obesity (2008) 32, 740–748; doi:10.1038/sj.ijo.0803782; published online 8 January 2008 [ABSTRACT FROM AUTHOR]

The three-dimensional conservation equations relating energy and momentum transfer in a vibrated three-dimensional granular bed have been solved numerically by the finite element method. Two closures based on granular kinetic theory were used: one, the standard Fourier law relating heat flux to temperature gradient and the other, including an additional concentration gradient term. Each prediction of the two-dimensional axisymmetric granular temperature and packing fraction fields was compared against a one-dimensional model and three-dimensional experimental results, acquired using the technique of positron emission particle tracking. Both closures resulted in solutions that were in reasonable agreement with the experimental results, but it was found that differences between the predictions of each of the closures were relatively small in comparison to the anisotropy of the experimentally determined temperature distribution. [ABSTRACT FROM AUTHOR]

A comparison of the predictions of a simple kinetic theory with experimental and numerical results for a vibrated granular bed consisting of nearly elastic particles of two sizes has been performed. The results show good agreement between the data sets for a range of numbers of each size of particle, and are particularly good for particle beds containing similar proportions of each species. The agreement suggests that such a model may be a good starting point for describing polydisperse systems of granular flows. [ABSTRACT FROM AUTHOR]

The velocity autocorrelation functions of grains moving in highly fluidized three-dimensional granular beds have been determined for the first time. Positron emission particle tracking was used to determine the location of a tracer particle. The velocity auto- and cross-correlation functions were then calculated following estimation of the velocities of the grains. The cross-correlations were found to be about zero for all times and the velocity autocorrelation functions differed in the x and y directions. A numerical study was performed to model the velocity auto-correlation function in the y-direction and this analysis was found to capture many of the observed experimental features. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Tissue engineered bone scaffolds are potential alternatives to bone allografts and autografts. Porous scaffolds based on triply periodic minimal surfaces (TPMS) are good candidates for tissue growth because they offer high surface-to-volume ratio, have tailorable stiffness, and can be easily fabricated by additive manufacturing. However, the range of TPMS scaffold types is extensive, and it is not yet clear which type provides the fastest cell or tissue growth while being sufficiently stiff to act as a bone graft. Nor is there currently an established methodology for TPMS bone scaffold design which can be quickly adopted by medical designers or biologists designing implants. In this study, we examine six TPMS scaffold types for use as tissue growth scaffolds and propose a general methodology to optimise their geometry. At the macro-scale, the optimisation routine ensures a scaffold stiffness within suitable limits for bone, while at the micro-scale it maximises the cell growth rate. The optimisation procedure also ensures the scaffold pores are of sufficient diameter to allow oxygen and nutrient delivery via capillaries. Of the examined TPMS structures, the Lidinoid and Split P cell types provide the greatest cell growth rates and are therefore the best candidates for bone scaffolds. [ABSTRACT FROM AUTHOR]

The article reports that there is a conspicuous phenomenon in state mental hospitals relating to fluctuations of admission rates. These seem to occur with almost predictable regularity and have been attributed to changing economic, social, and climatic conditions. William N. Chambers' study dealt exclusively with seasonal variations in neuro-psychiatric admissions to a military hospital, which were highest in March. P.A. Hauck compared monthly admission rates in four state hospitals for three years, with highest admission rate in January. P.A. Hauck and R.G. Armstrong examined admission rates to a state hospital over a 37 year period, the data categorized by sexes. The month of highest admissions was June.

Material properties such as hardness can be dependent on the size of the indentation load when that load is small, a phenomenon known as the indentation size effect (ISE). In this work an inverse finite element method (IFEM) is used to investigate the ISE, with reference to experiments with a Berkovich indenter and an aluminium test material. It was found that the yield stress is highly dependent on indentation depth and in order to simulate this, an elastoplastic constitutive relation in which yielding varies with indentation depth/load was developed. It is shown that whereas Young's modulus and Poisson's ratio are not influenced by the length scale over the range tested, the amplitude portion of yield stress, which is independent of hardening and corresponds to the initial stress for a bulk material, changes radically at small indentation depths. Using the proposed material model and material parameters extracted using IFEM, the indentation depth-time and load-depth plots can be predicted at different loads with excellent agreement to experiment; the relative residual achieved between FE modelling displacement and experiment being less than 0.32%. An improved method of determining hardness from nanoindentation test data is also presented, which shows goof agreement with that determined using the IFEM. [ABSTRACT FROM AUTHOR]

In this paper, we address the behaviour of lacquer coatings similar to that found on the Mazarin Chest, an important Japanese lacquerware artefact currently held by the Victoria and Albert Museum (V&A) in London. The response of Japanese lacquer (urushi) to changes in environmental conditions was investigated by examining the deflection of a glass substrate coated with a thin film of urushi subjected to changes of humidity. This deflection, measured using phase-shifting interferometry, was then used to determine the two in-plane hygral stress components. Results were compared for two sample conditioning regimes--subjected to intense UV ageing and no ageing--each at a range of relative humidity (RH) steps. The changes in humidity were found to cause rapid stress changes in the lacquers, which then relax over much longer time scales. A simple one-dimensional model of the moisture transport and the stress development is shown to be effective in describing the response of the material to changes in environmental RH. [ABSTRACT FROM AUTHOR]

Introduction Since the designation of people as Hispanic involves the amalgamation of a number of different cultures and languages, we sought to test the hypothesis that menopausal symptoms would differ among Hispanic women, based upon country of origin and degree of acculturation. Methods A total of 419 women, aged 42–52 years at baseline, were categorized as: Central American (CA, n = 29) or South American (SA, n = 106), Puerto Rican (PR, n = 56), Dominican (D, n = 42), Cuban (Cu, n = 44) and non-Hispanic Caucasian ( n = 142). We assessed vasomotor symptoms, vaginal dryness and trouble in sleeping. Hispanics and non-Hispanic Caucasians were compared using the χ2 test, t test or non-parametric alternatives; ANOVA or Kruskal–Wallis testing examined differences among the five Hispanic sub-groups. Multivariable regression models used PR women as the reference group. Results Hispanic women were overall less educated, less acculturated ( p < 0.001 for both) than non-Hispanic Caucasians and more of them reported vasomotor symptoms (34.1–72.4% vs. 38.3% among non-Hispanic Caucasians; p = 0.0293) and vaginal dryness (17.9–58.6% vs. 21.1% among non-Hispanic Caucasians, p = 0.0287). Among Hispanics, more CA women reported vasomotor symptoms than D, Cu, SA, or PR women (72.4% vs. 45.2%, 34.1%, 50.9%, and 51.8%, respectively). More CA (58.6%) and D women (38.1%) reported vaginal dryness than PR (17.9%), Cu (25.0%) and SA (31.4%) women. More PR and D women reported trouble in sleeping (66.1 and 64.3%, respectively) compared to CA (51.7%), Cu (36.4%), and SA (45.3%) women. Conclusion Symptoms associated with menopause among Hispanic women differed by country of origin but not acculturation. Central American women appear to be at greatest risk for both vasomotor symptoms and vaginal dryness. [ABSTRACT FROM AUTHOR]

The objective of this study was to determine if a high fat diet having a 2:1 saturated-polyunsaturated fatty acid ratio exacerbates signs of copper deficiency. Male weanling Long-Evans rats were randomly placed into one of the following treatment groups: adequate copper low fat or deficient copper high fat. The levels of fat used were 31 or 12% of daily energy, and copper concentrations were 94.5 micromol/kg and <15.8 micromol/kg in the copper-adequate and copper-deficient diets, respectively. Cardiac hypertrophy as well as lower liver copper levels and superoxide dismutase activity were observed in both groups of copper-deficient rats. Irrespective of copper level, consumption of the high fat diet resulted in the thickening of the interventricular septum and left ventricular free wall. Electrocardiograms revealed that the copper-deficient high fat diet led to a significantly smaller QT interval compared with all other groups. Significantly greater S-wave voltage due to copper deficiency was observed. Significantly lower heart cytochrome c oxidase (CCO) activity was found in the copper-deficient groups with the copper deficient high fat group showing the lowest activity. Western blots of the cardiac non-myofibrillar fraction demonstrated lower amounts of CCO nuclear encoded peptides in the copper-deficient groups, with the least amount seen in the copper-deficient high fat treatment. These data suggest that a high level of dietary fat exacerbates some of the signs of copper deficiency. [ABSTRACT FROM AUTHOR]

• Supramolecular polyurethanes with varied loadings of a low molecular weight bis-urea additive. • LMWAs cooperatively self-assemble with supramolecular polyurethanes. • LMWAs enhance the properties of the addressable and healable polymer networks. Low molecular weight additives which can cooperatively self-assemble with supramolecular polyurethanes via complementary hydrogen bonding interactions offer an attractive route to enhancing the properties of addressable polymer networks. Here, we present the design, synthesis, characterisation and mechanical properties of a series of supramolecular polyurethanes with varied loadings of a low molecular weight bis-urea additive. These additives are able to self-assemble with analogous recognition motifs within the supramolecular polyurethanes to form polar 'hard' domains, promoting phase separation within the material and, crucially, increasing the strength of the polymer network. In addition, the bis-urea additive is a by-product within the polymerisation and thus can be synthesised in situ , without the need for complex purification or blending. The mechanical properties of these reinforced polymers were enhanced when compared to the pristine supramolecular polyurethane alone, as a result of higher degrees of order within the polymer matrix. Furthermore, a formulation comprising the small molecule blended with the supramolecular polyurethane was produced to examine the effect of material preparation and filler dispersion within the polymer matrix. Interestingly, the mechanical performance of a blended material was diminished as a result of modest dispersion and incorporation within the polymer matrix. These findings thus demonstrate a facile, one-pot, method that does not require purification to produce reinforced supramolecular polyurethanes. This methodology may find use in industrial applications in which enhancements to the physical and mechanical properties can be easily achieved through the in situ synthesis of low molecular weight additives within the polymerisation. [ABSTRACT FROM AUTHOR]

Innovative Additive Manufacturing (AM) technologies like Selective Laser Melting (SLM) could prove to be efficient for the processing of brittle silicon steel (Fe-Si) with high silicon content. This research elucidates the effects of heat-treatment on the microstructure of SLM-built high silicon steel, with particular emphasis on the formation of ordered phases, which are known to cause undesired material embrittlement. Silicon steel with 6.9 wt % Si is produced by SLM and investigated performing Differential Scanning Calorimetry (DSC), microstructure analysis and hardness measurements. As-built Fe-Si parts are found to consist primarily of disordered A2 phase as the high cooling rates typical of SLM suppress the ordering phase transformations. It is shown how heat treatments can be applied to modify the state of ordering and morphology of the rapidly solidified microstructure. By shedding light on the phase-ordering mechanisms and the effect of heat treatments on microstructure of high-Si steel built by SLM, the present study paves the way towards the optimisation of the mechanical and magnetic properties of this alloy. [ABSTRACT FROM AUTHOR]

Method To test the hypothesis that psychosocial symptomatology differs by country of origin and acculturation among Hispanic women, we examined 419 women, aged 42-52 years at baseline, enrolled in the New Jersey site of the Study of Women's Health Across the Nation (SWAN). Women were categorized into six groups: Central (CA, n = 29) or South American (SA, n = 106), Puerto Rican (PR, n = 56), Dominican (D, n = 42), Cuban (Cu, n = 44) and non-Hispanic Caucasian (NHC, n = 142). Acculturation, depressive symptoms, hostility/cynicism, mistreatment/discrimination, sleep quality, social support, and perceived stress were assessed at baseline. Physical functioning, trait anxiety and anger were assessed at the fourth annual follow-up. Comparisons between Hispanic and non-Hispanic Caucasians used χ2, t test or non-parametric alternatives; ANOVA or Kruskal-Wallis testing examined differences among the five Hispanic sub-groups. Multivariable regression models used PR women as the reference group. Results Hispanic women were overall less educated, less acculturated ( p < 0.001 for both) and reported more depressive symptoms, cynicism, perceived stress, and less mistreatment/discrimination than NHCs. Along with D women, PR women reported worse sleep than Cu women ( p < 0.01) and more trait anxiety than SA and Cu women ( p < 0.01). Yet, PR women were most acculturated (21.4% highly acculturated vs. CA (0.0%), D (4.8%), SA (4.8%) and Cu (2.3%) women; p < 0.001). In regression models, PR women reported depressive symptoms more frequently than D, Cu, or SA women, and reported trait anxiety more frequently than Cu or SA women. Greater acculturation was associated with more favorable psychosocial status, but PR ethnicity was negatively related to psychosocial status. Conclusion Psychosocial symptomatology among Hispanic women differs by country of origin and the relatively adverse profile of Puerto Rican women is not explained by acculturation. [ABSTRACT FROM AUTHOR]

Vascular calcification is associated with an adverse prognosis in end-stage renal disease. It can be accurately quantitated with computed tomography but simple in-office techniques may provide equally useful information. Accordingly we compared the results obtained with simple non-invasive techniques with those obtained using electron beam tomography (EBT) for coronary artery calcium scoring (CACS) in 140 prevalent hemodialysis patients. All patients underwent EBT imaging, a lateral X-ray of the lumbar abdominal aorta, an echocardiogram, and measurement of pulse pressure (PP). Calcification of the abdominal aorta was semiquantitatively estimated with a score (Xr-score) of 0–24 divided into tertiles, echocardiograms were graded as 0–2 for absence or presence of calcification of the mitral and aortic valve and PP was divided in quartiles. The CACS was elevated (mean 910±1657, median 220). The sensitivity and specificity for CACS100 was 53 and 70%, for calcification of either valve and 67 and 91%, respectively, for Xr-score 7. The area under the curve for CACS100 associated with valve calcification and Xr-score was 0.62 and 0.78, respectively. The likelihood ratio (95% confidence interval) of CACS100 was 1.79 (1.09, 2.96) for calcification of either valve and 7.50 (2.89, 19.5) for participants with an Xr-score 7. In contrast, no association was present between PP and CACS. In conclusion, simple measures of cardiovascular calcification showed a very good correlation with more sophisticated measurements obtained with EBT. These methodologies may prove very useful for in-office imaging to guide further therapeutic choices in hemodialysis patients.Kidney International (2006) 70, 1623–1628. doi:10.1038/sj.ki.5001820; published online 6 September 2006 [ABSTRACT FROM AUTHOR]

We report the results of nuclear magnetic resonance imaging experiments on granular beds of mustard grains fluidized by vertical vibration at ultrasonic frequencies. The variation of both granular temperature and packing fraction with height was measured within the three-dimensional cell for a range of vibration frequencies, amplitudes and numbers of grains. Small increases in vibration frequency were found--contrary to the predictions of classical 'hard-sphere' expressions for the energy flux through a vibrating boundary--to result in dramatic reductions in granular temperature. Numerical simulations of the grain-wall interactions, using experimentally determined Hertzian contact stiffness coefficients, showed that energy flux drops significantly as the vibration period approaches the grain-wall contact time. The experiments thus demonstrate the need for new models for 'soft-sphere' boundary conditions at ultrasonic frequencies. [ABSTRACT FROM AUTHOR]