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Biomolecular MRI reporters: Evolution of new mechanisms

Magnetic resonance imaging (MRI) is a powerful technique for observing the function of specific cells and molecules inside living organisms. However, compared to optical microscopy, in which fluorescent protein reporters are available to visualize hundreds of cellular functions ranging from gene expression and chemical signaling to biomechanics, to date relatively few such reporters are available for MRI. Efforts to develop MRI-detectable biomolecules have mainly focused on proteins transporting paramagnetic metals for T_1 and T_2 relaxation enhancement or containing large numbers of exchangeable protons for chemical exchange saturation transfer. While these pioneering developments established several key uses of biomolecular MRI, such as imaging of gene expression and functional biosensing, they also revealed that low molecular sensitivity poses a major challenge for broader adoption in biology and medicine. Recently, new classes of biomolecular reporters have been developed based on alternative contrast mechanisms, including enhancement of spin diffusivity, interactions with hyperpolarized nuclei, and modulation of blood flow. These novel reporters promise to improve sensitivity and enable new forms of multiplexed and functional imaging

High temperature pile irradiation of the n -heptane-hydrogen system

A pilot unit for the high-temperature irradiation of flowing reactants was designed for the beam port of a nuclear reactor. Radiation-thermal cracking of the n -heptane-hydrogen system was studied with molal H 2 /C 7 ratios from 0 to 5 at 250 lb./sq. in., 600° to 750°F., 2 to 8 min. residence time, and up to 3,600 rep./min. Although conversions were low, the decomposition rate was significantly increased by radiation giving G values > 10 3 . Product distributions were not significantly altered by radiation. These results, while different from low-temperature data, appear consistent with other published high-temperature results. Radiation yields were found to be reasonably linear with total dose from 0 to 14 krep., but a twofold increase was observed in passing from a molal H 2 /C 7 ratio of 0 to 0.5.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/37319/1/690070413_ftp.pd

High-precision determination of the critical exponents for the lambda-transition of 4He by improved high-temperature expansion

We determine the critical exponents for the XY universality class in three dimensions, which is expected to describe the $\lambda$-transition in ${}^4$He. They are obtained from the analysis of high-temperature series computed for a two-component $\lambda\phi^4$ model. The parameter $\lambda$ is fixed such that the leading corrections to scaling vanish. We obtain $\nu = 0.67166(55)$, $\gamma = 1.3179(11)$, $\alpha=-0.0150(17)$. These estimates improve previous theoretical determinations and agree with the more precise experimental results for liquid Helium.Comment: 8 pages, revte

The magnitude of educational disadvantage amongst indigenous minority groups in Australia.

Indigenous groups are amongst the most disadvantaged minority groups in the developed world. This paper examines the educational disadvantage of indigenous Australians by assessing academic performance at a relatively early age. We find that, by the age of 10, indigenous Australians are substantially behind non-indigenous Australians in academic achievement. Their relative performance deteriorates further over the next 2 years. School and locality do not appear to be important determinants of the indigenous to non-indigenous achievement gap. However, geographic remoteness, indigenous ethnicity and language use at home have a marked influence on educational achievement. A current focus of Australian indigenous policy is to increase school resources. Our results suggest that this will not eliminate indigenous educational disadvantage on its own

Point mutations in the C-terminus of HIV-1 gp160 reduce apoptosis and calmodulin binding without affecting viral replication

AbstractOne hallmark of AIDS progression is a decline in CD4+ T lymphocytes, though the mechanism is poorly defined. There is ample evidence that increased apoptosis is responsible for some, if not all, of the decline. Prior studies have shown that binding of cellular calmodulin to the envelope glycoprotein (Env) of HIV-1 increases sensitivity to fas-mediated apoptosis and that calmodulin antagonists can block this effect. We show that individual mutation of five residues in the C-terminal calmodulin-binding domain of Env is sufficient to significantly reduce fas-mediated apoptosis in transfected cells. The A835W mutation in the cytoplasmic domain of gp41 eliminated co-immunoprecipitation of Env with calmodulin in studies with stably transfected cells. Four point mutations (A835W, A838W, A838I, and I842R) and the corresponding region of HIV-1 HXB2 were cloned into the HIV-1 proviral vector pNL4-3 with no significant effect on viral production or envelope expression, although co-immunoprecipitation of calmodulin and Env was decreased in three of these mutant viruses. Only wild-type envelope-containing virus induced significantly elevated levels of spontaneous apoptosis by day 5 post-infection. Fas-mediated apoptosis levels positively correlated with the degree of calmodulin co-immunoprecipitation, with the lowest apoptosis levels occurring in cells infected with the A835W envelope mutation. While spontaneous apoptosis appears to be at least partially calmodulin-independent, the effects of HIV-1 Env on fas-mediated apoptosis are directly related to calmodulin binding

An Analysis of the Relationship Between Leadership Styles and Community Development in Selected Counties of the Alabama Black Belt

Leadership styles are surmised to influence community development. The study, therefore, assessed the relationship between leadership styles and community development in selected Black Belt Counties of Alabama. Data were collected from a purposive sample of 38 locally elected officials, and were analyzed using descriptive statistics and multiple regression analysis. The most dominant leadership style selected was participating; followed by telling and selling, with identical ratings; delegating; autocratic, and democratic. The most preferred economic indicators were improving the physical infrastructure and constructing a 24-hour health facility. Additionally, participants indicated that constructing or improving of an industrial park; locating a manufacturing company, and locating a tier-1 automobile supplier are important facets of community development. Furthermore, the more preferred educational factor was providing after school programs, and the more preferred social factor was providing recreational facilities. The regression results revealed that of the economic indicators, democratic leadership style had the most relative importance; of the educational indicators, telling leadership style had the most relative importance, and of the social indicators, delegating leadership style had the most relative importance. For the overall community development indicator, democratic leadership style had the most relative importance. Keywords: Leadership Styles, Leadership, Community Development, Black Bel

An Analysis of the Relationship between Socioeconomic Factors and Leadership Styles in Selected Counties of the Alabama Black Belt

Socioeconomic factors are important to leadership styles and may have an influence on leadership styles. The study assessed the relationship between socioeconomic factors and leadership styles in selected counties of the Alabama Black Belt. Data were collected from a purposive sample of 38 locally elected officials, and were analyzed using descriptive statistics and multiple regression analysis. The results showed that there were more male, Black, “older”, educated, moderate- to moderately high-income household, and low- to medium-tenured elected officials than otherwise. The most dominant leadership style was participating; followed by telling and selling. Gender and age had enhancing effects (i.e., positive relative impacts) on the participating leadership style; race had enhancing effects on the selling, delegating, and democratic leadership styles; education had enhancing effects on the selling, participating, and delegating leadership styles; household income had enhancing effects on all the leadership styles, and tenure had an enhancing effect on the autocratic leadership style. This suggests that the officials are more prone to use the said leadership styles vis-à-vis the particular socioeconomic factors. Keywords: Leadership styles, Leadership, Socioeconomic factors, Black Bel

Extending Sustainable Irrigation Opportunities to Socially and Historically Disadvantaged Farmers in the Alabama Black Belt to Support Commercial-Level Production

This paper focuses on providing sustainable irrigation opportunities to socially and historically disadvantaged farmers (SHDFs). The ability to provide steady production capacity through the use of renewable energy sources and microirrigation is innovative, in that it demonstrated how to develop and utilize a sustainable irrigation system in both energy and water conservation. This venture is also innovative in that it sought to provide SHDFs with irrigation in a state in which irrigation in agriculture is minimal, while at the same time, offsetting the energy costs that normally accompany irrigation. Several farmers are profiled in their participation in the irrigation program. The lessons learned will provide a starting point for a more permanent research, educational, and outreach partnership between the United States Department of Agriculture (USDA) and SHDF clientele. This relationship will lead to further strengthening the relationships between Tuskegee University and both participating farmers and USDA agencies. Key Words: Irrigation, Small Farmers, Agricultural Sustainability, Solar Energy, Black Bel

Site-specific incorporation of phosphotyrosine using an expanded genetic code.

Access to phosphoproteins with stoichiometric and site-specific phosphorylation status is key to understanding the role of protein phosphorylation. Here we report an efficient method to generate pure, active phosphotyrosine-containing proteins by genetically encoding a stable phosphotyrosine analog that is convertible to native phosphotyrosine. We demonstrate its general compatibility with proteins of various sizes, phosphotyrosine sites and functions, and reveal a possible role of tyrosine phosphorylation in negative regulation of ubiquitination