Plastic Flow of Saturated, Consolidated Alumina Powder Compacts: Particle Size and Binary Mixtures

The flow stresses and relaxed yield stresses of saturated, alumina powder compacts that have been consolidated via pressure filtration were measured in unconstrained uniaxial compression. Two different sized powders, as well as binary mixtures of the two powders, were investigated. Bodies that were consolidated from slurries of larger particles had lower flow and relaxed yield stresses, relative to bodies that were made of small particles with the same relative density and solution conditions. This result is primarily due to the lower number of particle-particle contacts per unit volume in the body that was made of the large particles. The flow stress of the body can be controlled by adjusting the fraction of large particles to small particles.     

Cleaning AFM colloidal probes by mechanically scrubbing with supersharp “brushes”

Contamination control of atomic force microscope (AFM) tips (including standard but supersharp imaging tips and particle/colloidal probes) is very important for reliable AFM imaging and surface/interface force measurements. Traditional cleaning methods such as plasma, UV–ozone and solvent treatments have their shortcomings. Here, we demonstrate that calibration gratings with supersharp spikes can be employed to scrub away contaminants accumulated on a colloidal sphere probe by scanning the probe against the spikes at high load at constant-force mode. The present method is superior to traditional cleaning methods in several aspects. First, accumulated lump-like organic/inorganic material can be removed; second, removal is non-destructive and highly efficient based on a “targeted removal” strategy; third, removal and probe shape/morphology study can be completed in a single step (we report, to our best knowledge, the first evidence of the wear of the colloidal sphere during force measurements); and fourth, both colloidal/particle probes and standard but supersharp AFM imaging tips can be treated.     

Improvement of dry float–sink separation of smaller sized spheres by reducing the fluidized bed height

In this study, the influence of the fluidized bed height on the float–sink of different sized spheres in a gas–solid fluidized bed was investigated. Fluidized beds with heights h = 200, 150, 100 and 50 mm were prepared using a cylindrical column of inner diameter = 290 mm and a mixture of zircon sand and iron powder as the fluidized medium. Float–sink experiments were carried out using density adjusted spheres of diameter D_sp = 40, 30, 20 and 10 mm. It was found that the float–sink performance at D_sp ?20 mm is not affected by the height of the bed, and the sharpness of separation (the density range where spheres neither float nor sink completely) is less than or equal to 200 kg/m³. In the case of D_sp = 10 mm, the sharpness of separation is a larger value (1100 kg/m³ at h = 200 mm), whereas it decreases with decreasing h and is 400 kg/m³ at h = 50 mm. The fluctuation of the surface height of the fluidized bed was visually recorded. The fluctuation is reduced by reducing h. The fluctuation vs. h correlates with the sharpness of separation at D_sp = 10 mm vs. h. These results indicate that the dry float–sink separation of smaller sized spheres is improved as the fluctuation of fluidized bed surface is decreased by reducing the fluidized bed height.     

Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy

Dynamic nuclear polarization (DNP) NMR can enhance sensitivity but often comes at the price of a substantial loss of resolution. Two major factors affect spectral quality: low‐temperature heterogeneous line broadening and paramagnetic relaxation enhancement (PRE) effects. Investigations by NMR spectroscopy, isothermal titration calorimetry (ITC), and EPR revealed a new substantial affinity of TOTAPOL to amyloid surfaces, very similar to that shown by the fluorescent dye thioflavin‐T (ThT). As a consequence, DNP spectra with remarkably good resolution and still reasonable enhancement could be obtained at very low TOTAPOL concentrations, typically 400 times lower than commonly employed. These spectra yielded several long‐range constraints that were difficult to obtain without DNP. Our findings open up new strategies for structural studies with DNP NMR spectroscopy on amyloids that can bind the biradical with affinity similar to that shown towards ThT.     

Spouses' use of pressure and persuasion to promote osteoarthritis patients' medical adherence after orthopedic surgery.

Objective: The authors investigated health-related effects of social control (influence) that spouses exert in relation to osteoarthritis patients' medical adherence after total knee replacement surgery. Patients' behavioral and emotional responses to control were examined as mediators of associations between spouses' use of two control strategies (pressure, persuasion) and patients' physical and psychological recovery. Design: The authors used a three-wave panel design with assessments at one month before surgery, 1 month and 3 months after surgery. Data were collected during in-person interviews with 70 married, older adult patients. Main Outcome Measures: Recovery outcomes were assessed as improvement in knee limitations and depressive symptoms at the 3 month follow-up. Results: Spousal pressure and persuasion at one month postsurgery were indirectly associated with patients' recovery outcomes through patients' positive emotional responses to control. Conclusion: Although there are often immediate behavioral benefits in response to partners' use of both pressure and persuasion, the long-term health effects of these strategies seem to be accounted for by their opposing links to positive emotions. Findings further refine theory on health-related social control in marriage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Impact of packaging properties on the physical-chemical-microbiological-sensory characteristics of Ricotta cheese during storage

Ricotta is a highly perishable cheese of which shelf-life is strongly influenced by the properties of packages in which it is stored. Four plastic packages currently in use in Italy (IT), Romania (RO), Slovenia (SLO), and Spain (SP) are characterized in term of structure, barrier, and antimicrobial properties, and their efficiency in the ricotta storage at 4°C is assessed. Differential scanning calorimetry and Fourier-transform infrared spectroscopy analysis indicate that the IT and SP packages are made of low-density polyethylene and the RO and SLO packages consist of polyethylene and polyamide 6. Permeability to the water vapour and oxygen transmission rate vary as follows: IT>SLO > RO > SP and SP > IT>RO > SLO, respectively. The SP package expressed the highest antimicrobial inhibition whilst the IT package the lowest. The maximum amounts of volatile compounds in cheese were reached after 3 days in the IT and SP packages and after 6 days in the SLO and RO packages. The score 2.8 for cheese overall acceptability was exceeded after 7 days in the IT, RO, and SP packages and 6 days in the SLO package. Barrier properties of packages significantly influence the shelf-life of ricotta. Low barrier properties resulted in high level of oxygen and water vapours inside the headspace of packages ultimately favour the microbial development. The simultaneous compliance of microbiological safety level and overall acceptability score gives ricotta a shelf-life of 3 days in the IT, RO, and SP packages and 1 day in the SLO package.     

Managing the stress of caring in ITU: a reflective practice group

Working in a busy intensive therapy unit can be psychologically demanding. A reflective practice group was set up to provide staff with a forum for discussion and support in an effort to manage the stress of caring in such an environment. There was no planned agenda and staff were encouraged to speak freely about both the rewarding and exacting aspects of the job. The weekly sessions were facilitated by staff from outside and unit. Their approach encouraged staff to develop and share their insights and experiences and helped to generate new ways of coping with the personal, interpersonal and professional demands of their work.     

Local control of ovarian steroidogenesis

A number of putative paracrine factors are now thought to interact with FSH in the control of ovarian steroidogenesis. The relative importance of these factors remains to be determined, but the presence of the insulin-like growth factors and their binding proteins and the mechanism of control of the latter through the local production of proteases suggests a role for this system in folliculogenesis. We have demonstrated over-production of steroid hormones in tissue from women with polycystic ovaries. Theca cells in monolayer culture produced excessive amounts of progesterone and androstenedione and granulosa cell oestradiol production was considerably enhanced in response to FSH. Recent evidence points to a genetic defect in the expression or translation of steroidogenic hormones as a cause of excess androgen production, but the gene or genes involved has not been established. Data from our group suggest that granulosa cells from anovulatory polycystic ovaries are prematurely matured and we hypothesize that this is due to the interaction of the raised circulating insulin levels with LH in these follicles, an interaction that results in arrested follicular growth.     

The prevalence of risk factors among women in the United States by race and age, 1992-1994: opportunities for primary and secondary prevention

OBJECTIVE: To analyze the prevalence of 11 modifiable behavioral risk factors, including multiple risk factors, among white, black, Asian and Pacific Islander, American Indian, and Hispanic women in the United States. DESIGN: We used Behavioral Risk Factor Surveillance System (BRFSS) data for 1992 to 1994 to examine risk factors (smoking; obesity; diabetes; heavy alcohol consumption; sedentary lifestyle; and inadequate use of seat belts, pap smears, consumption of fruits or vegetables, mammography and colorectal screening, and immunization), among women age 18 to 49, 50 to 64, and 65 and older. We also conducted a multiple regression analysis, comparing the odds of having either 1-2 versus 0 or 3 or more versus 0 risk factors among racial/ethnic groups, controlling for education and family income, to see if racial/ethnic differences can be attributed to socioeconomic differences. RESULTS: US women engage in a variety of behaviors that place them at risk for many causes of morbidity and mortality. Risk profiles vary substantially among racial/ethnic populations: Pacific Islanders have relatively low prevalences of most major risk factors, while blacks and American Indians have relatively high prevalences of many major risk factors. Prevalence differences among racial/ethnic populations are diminished but not eliminated when socioeconomic factors are accounted for. CONCLUSIONS: Appropriately designed programs to help women reduce their behavioral risk factors are needed. Action by health care providers, communities, and policy makers can substantially improve the health of women in the United States.