Multidisciplinary Graduate Curriculum in Support of the Biobased Products Industry

The project had a dominant education component. The project involved revising curriculum to educate traditional engineering students in the emerging field of industrial biotechnology. New classes were developed and offered. As a result, the curriculum of the Colorado School of Mines was expanded to include new content. Roughly 100 undergraduates and about 10 graduate students each year benefit from this curricular expansion. The research associated with this project consisted of developing new materials and energy sources from renewable resources. Several significant advances were made, most importantly the heat distortion temperature of polylactide (PLA) was increased through the addition of cellulosic nanowhiskers. The resulting ecobionanocomposites have superior properties which enable the use of renewable resource based plastics in a variety of new applications. Significant amounts of petroleum are thereby saved and considerable environmental benefits also result. Effectiveness and economic feasibility of the project proved excellent. The educational activities are continuing in a sustainable fashion, now being supported by tuition revenues and the normal budgeting of the University. The PI will be teaching one of the newly developed classes will next Fall (Fall 2006), after the close of the DOE grant, and again repeatedly into the future. Now established, the curriculum in biobased products and energy will grow and evolve through regular teaching and revision. On the research side, the new plastic materials appear economically feasible and a new collaboration between the PI’s group and Sealed Air, a major food-packaging manufacturer, has been established to bring the new green plastics to market. Public benefits of the project are noteworthy in many respects. These include the development of a better educated workforce and citizenry capable of providing technological innovation as a means of growing the economy and providing jobs. In particular, the educational components addressing the production of bioethanol, biodiesel, and bioplastics provide graduates that can assist American industries in including greater renewable content in feedstocks for materials and fuels. Finally, the collaboration fostered by this grant led to the drafting of a new book entitled, Bioengineering for Sustainability: Materials and Fuels for the 21st Century. This text will be widely available to the public interested in learning more about these important areas of technology

Fluidized Bed Polymer Particle ALD Process for Producing HDPE/Alumina Nanocomposites

Micron-sized High Density Polyethylene (HDPE) particles were coated with ultrathin alumina (Al2O3) films in a Fluidized Bed Reactor (FBR) by Atomic Layer Deposition (ALD) at 77 ºC. Al2O3 films on the HDPE particles were confirmed by different methods. These particles were extruded conventionally with the ceramic shells mixing intimately in the polymer matrix. The successful dispersion of the Al2O3 shells in the polymer matrix following extrusion was confirmed using cross sectional Transmission Electron Microscopy (TEM)

The medical student

The Medical Student was published from 1888-1921 by the students of Boston University School of Medicine

Mammographic density and ageing:A collaborative pooled analysis of cross-sectional data from 22 countries worldwide

BACKGROUND: Mammographic density (MD) is one of the strongest breast cancer risk factors. Its age-related characteristics have been studied in women in western countries, but whether these associations apply to women worldwide is not known. METHODS AND FINDINGS: We examined cross-sectional differences in MD by age and menopausal status in over 11,000 breast-cancer-free women aged 35-85 years, from 40 ethnicity- and location-specific population groups across 22 countries in the International Consortium on Mammographic Density (ICMD). MD was read centrally using a quantitative method (Cumulus) and its square-root metrics were analysed using meta-analysis of group-level estimates and linear regression models of pooled data, adjusted for body mass index, reproductive factors, mammogram view, image type, and reader. In all, 4,534 women were premenopausal, and 6,481 postmenopausal, at the time of mammography. A large age-adjusted difference in percent MD (PD) between post- and premenopausal women was apparent (-0.46 cm [95% CI: -0.53, -0.39]) and appeared greater in women with lower breast cancer risk profiles; variation across population groups due to heterogeneity (I2) was 16.5%. Among premenopausal women, the √PD difference per 10-year increase in age was -0.24 cm (95% CI: -0.34, -0.14; I2 = 30%), reflecting a compositional change (lower dense area and higher non-dense area, with no difference in breast area). In postmenopausal women, the corresponding difference in √PD (-0.38 cm [95% CI: -0.44, -0.33]; I2 = 30%) was additionally driven by increasing breast area. The study is limited by different mammography systems and its cross-sectional rather than longitudinal nature. CONCLUSIONS: Declines in MD with increasing age are present premenopausally, continue postmenopausally, and are most pronounced over the menopausal transition. These effects were highly consistent across diverse groups of women worldwide, suggesting that they result from an intrinsic biological, likely hormonal, mechanism common to women. If cumulative breast density is a key determinant of breast cancer risk, younger ages may be the more critical periods for lifestyle modifications aimed at breast density and breast cancer risk reduction

Current opinion on the role of testosterone in the development of prostate cancer: a dynamic model

Background: Since the landmark study conducted by Huggins and Hodges in 1941, a failure to distinguish between the role of testosterone in prostate cancer development and progression has led to the prevailing opinion that high levels of testosterone increase the risk of prostate cancer. To date, this claim remains unproven. Presentation of the Hypothesis: We present a novel dynamic mode of the relationship between testosterone and prostate cancer by hypothesizing that the magnitude of age-related declines in testosterone, rather than a static level of testosterone measured at a single point, may trigger and promote the development of prostate cancer. Testing of the Hypothesis: Although not easily testable currently, prospective cohort studies with population-representative samples and repeated measurements of testosterone or retrospective cohorts with stored blood samples from different ages are warranted in future to test the hypothesis. Implications of the Hypothesis: Our dynamic model can satisfactorily explain the observed age patterns of prostate cancer incidence, the apparent conflicts in epidemiological findings on testosterone and risk of prostate cancer, racial disparities in prostate cancer incidence, risk factors associated with prostate cancer, and the role of testosterone in prostate cancer progression. Our dynamic model may also have implications for testosterone replacement therapy

Solution and melt viscoelastic properties of controlled microstructure poly(lactide)

A series of controlled microstructure poly(lactide) (PLA) samples were synthesized using a novel chiral dinuclear indium catalyst capable of living polymerization of lactide. PLAs with different ratios of L- to D- monomer ratios of 100:0, 90:10, 75:25, 50:50, and 0:100 were investigated. The relationship between intrinsic viscosity and the absolute molar mass distribution of the samples obtained by light scattering gel permeation chromatography in tetrahydrofuran gives [η] = 0.014 + 0.75 Mw, a scaling law of typical coil dimensions of linear macromolecules in good solvent. The melt rheological study includes determination of zero-shear viscosity and its relationship with the molecular weight, the relaxation spectrum, and its relation with molecular weight characteristics, as well as plateau modulus and other important rheological parameters that are helpful in predicting the linear viscoelasticity of PLA. Emphasis is placed on the uniaxial melt behavior of these polymers. At low temperatures, significant strain hardening is observed, which gradually disappears with an increase in temperature and decrease of Hencky strain rate. The K-BKZ constitutive equation is used to model the experimental data. It is concluded that in spite of their linear structure, PLAs exhibit strain hardening which is not due to strain-induced crystallization, and it is solely due to the dynamics of molecular relaxation