972 research outputs found
Transformation of meta-stable calcium silicate hydrates to tobermorite: reaction kinetics and molecular structure from XRD and NMR spectroscopy
Understanding the integrity of well-bore systems that are lined with Portland-based cements is critical to the successful storage of sequestered CO2 in gas and oil reservoirs. As a first step, we investigate reaction rates and mechanistic pathways for cement mineral growth in the absence of CO2 by coupling water chemistry with XRD and NMR spectroscopic data. We find that semi-crystalline calcium (alumino-)silicate hydrate (Al-CSH) forms as a precursor solid to the cement mineral tobermorite. Rate constants for tobermorite growth were found to be k = 0.6 (± 0.1) × 10-5 s-1 for a solution:solid of 10:1 and 1.6 (± 0.8) × 10-4 s-1 for a solution:solid of 5:1 (batch mode; T = 150°C). This data indicates that reaction rates for tobermorite growth are faster when the solution volume is reduced by half, suggesting that rates are dependent on solution saturation and that the Gibbs free energy is the reaction driver. However, calculated solution saturation indexes for Al-CSH and tobermorite differ by less than one log unit, which is within the measured uncertainty. Based on this data, we consider both heterogeneous nucleation as the thermodynamic driver and internal restructuring as possible mechanistic pathways for growth. We also use NMR spectroscopy to characterize the site symmetry and bonding environment of Al and Si in a reacted tobermorite sample. We find two [4]Al coordination structures at δiso = 59.9 ppm and 66.3 ppm with quadrupolar product parameters (PQ) of 0.21 MHz and 0.10 MHz (± 0.08) from 27Al 3Q-MAS NMR and speculate on the Al occupancy of framework sites by probing the protonation environment of Al metal centers using 27Al{1H}CP-MAS NMR
Orally Bioavailable Dual MMP-1/MMP-14 Sparing, MMP-13 Selective Alpha-sulfone Hydroxamates
A series of phenyl piperidine α-sulfone hydroxamate derivatives has been prepared utilizing a combination of solution-phase and resin-bound library technologies to afford compounds that are potent and highly selective for MMP-13, are dual-sparing of MMP-1 and MMP-14 (MT1-MMP) and exhibit oral bioavailability in rats
Water Challenges for Geologic Carbon Capture and Sequestration
Carbon capture and sequestration (CCS) has been proposed as a means to dramatically reduce greenhouse gas emissions with the continued use of fossil fuels. For geologic sequestration, the carbon dioxide is captured from large point sources (e.g., power plants or other industrial sources), transported to the injection site and injected into deep geological formations for storage. This will produce new water challenges, such as the amount of water used in energy resource development and utilization and the “capture penalty” for water use. At depth, brine displacement within formations, storage reservoir pressure increases resulting from injection, and leakage are potential concerns. Potential impacts range from increasing water demand for capture to contamination of groundwater through leakage or brine displacement. Understanding these potential impacts and the conditions under which they arise informs the design and implementation of appropriate monitoring and controls, important both for assurance of environmental safety and for accounting purposes. Potential benefits also exist, such as co-production and treatment of water to both offset reservoir pressure increase and to provide local water for beneficial use
Anti-apoptotic proteins are oxidized by Aβ25–35 in Alzheimer's fibroblasts
AbstractWe have examined the effects of the beta-amyloid peptide (Aβ25–35) on fibroblasts derived from subjects with Alzheimer's disease (AD) and from age-matched controls. The peptide was significantly more cytotoxic to the AD-derived fibroblasts. The level of protein oxidation was also greater in the cells from AD subjects. Two-dimensional electrophoresis (2-DE) coupled with immunostaining for protein carbonylation revealed specific oxidation-sensitive proteins (OSPs) in both the control and AD-derived cells. Two specific OSPs were identified by mass spectrometry as heat shock protein 60 (HSP 60) and vimentin. Exposure of the cells to Aβ25–35 resulted in a twofold increase in the level of oxidation of these two OSPs in the cells derived from controls, but a ninefold increase in their level of oxidation in the fibroblasts from AD subjects. These observations are of particular interest because of the proposed anti-apoptotic roles of both HSP 60 and vimentin and our recent observation that these same two proteins are particularly susceptible to oxidation in neuronally derived cells
Explorations, Vol. 4, No. 2
Articles include:
Cover: Maya—painted clay figure from Jaina Island, Campeche, Mexico, 500-700A. D., approximately 100 percent. The clay figure is from a superb assemblage of pre-Hispanic materials from Mexico and Central America donated to the University of Maine’s Hudson Museum from the estate of William P Palmer III. In addition to this fine collection, Palmer donated an extensive array of objects from the Northwest Coast. Palmer earned his undergraduate degree in history and government from the University of Maine, and remained a strong, active supporter of the institution throughout his lifetime. More examples of objects from the Palmer Collection, including some pre-Columbian goldwork from Central America, may be found on page 10.
Editorial Reflections, by Carole J. Bombard
A Living Educational Experience: The Hudson Museum, by Richard G. Emerick
Molly in the Museum
Other Wonders, Other Ways
From Classroom Walls to High Tech Museum
Sharing Our Strengths: the development of youth conservation clubs in Pakistan, by James A. Sherburne
Up Close and Personal
Objects, Signs, and Symbols from Scafell to Chamonix: Visions of Mont Blanc, by Robert Brinkley
Public Service in Special Places: Music Education as Empowerment, by Susan Grindel Cosset Lambs, Floods and Stars, by Roberta Chester
Tuning the Immune System Fighting AIDS, Cancer and Other Diseases, by Anne P. Sherblom and Charles E. Moody
Why do they do it? One Graduate Student Explains, by Diane Carroll
Nutrition and Reproduction in Cows, by Barbara Barton and Diane Carroll
Diane Carroll: former graduate student Research News
Research New
A new multivariate measurement error model with zero-inflated dietary data, and its application to dietary assessment
In the United States the preferred method of obtaining dietary intake data is
the 24-hour dietary recall, yet the measure of most interest is usual or
long-term average daily intake, which is impossible to measure. Thus, usual
dietary intake is assessed with considerable measurement error. Also, diet
represents numerous foods, nutrients and other components, each of which have
distinctive attributes. Sometimes, it is useful to examine intake of these
components separately, but increasingly nutritionists are interested in
exploring them collectively to capture overall dietary patterns. Consumption of
these components varies widely: some are consumed daily by almost everyone on
every day, while others are episodically consumed so that 24-hour recall data
are zero-inflated. In addition, they are often correlated with each other.
Finally, it is often preferable to analyze the amount of a dietary component
relative to the amount of energy (calories) in a diet because dietary
recommendations often vary with energy level. The quest to understand overall
dietary patterns of usual intake has to this point reached a standstill. There
are no statistical methods or models available to model such complex
multivariate data with its measurement error and zero inflation. This paper
proposes the first such model, and it proposes the first workable solution to
fit such a model. After describing the model, we use survey-weighted MCMC
computations to fit the model, with uncertainty estimation coming from balanced
repeated replication.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS446 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
The Gut-Brain Axis in Healthy Females: Lack of Significant Association between Microbial Composition and Diversity with Psychiatric Measures
This study examined associations between the composition and diversity of the intestinal microbiota and measures of depression, anxiety, eating disorder psychopathology, stress, and personality in a group of healthy adult females
Impaired lymphocyte function in depressive illness
Mood states and immunity may be related. To investigate the immune status of patients with primary depressive illness, we compared lymphocytic responses to three different mitogens in 26 drug-free depressed patients and 20 normal controls of comparable age and sex. We observed a generalized and marked decrease in the lymphocyte mitogenic activity among the depressive group. This defect in lymphocyte function may be indicative of an impairment in cell-mediated immunity in patients with primary depressive illness.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25160/1/0000596.pd
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High-Quality Draft Genome Sequence of Desulfovibrio carbinoliphilus FW-101-2B, an Organic Acid-Oxidizing Sulfate-Reducing Bacterium Isolated from Uranium(VI)-Contaminated Groundwater.
Desulfovibrio carbinoliphilus subsp. oakridgensis FW-101-2B is an anaerobic, organic acid/alcohol-oxidizing, sulfate-reducing δ-proteobacterium. FW-101-2B was isolated from contaminated groundwater at The Field Research Center at Oak Ridge National Lab after in situ stimulation for heavy metal-reducing conditions. The genome will help elucidate the metabolic potential of sulfate-reducing bacteria during uranium reduction
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