176 research outputs found
Summary of the Status of Harvest Mice, Cricetidae: Reithrodontomys, in Arkansas
Although four species of harvest mice, Reithrodoniomyx, are known to occur in Arkansas, the distributional status of the genus in the state is poorly understood. Recent museum specimens significantly extend the range of R. megalotix and R. fulvescens in the state. R. megalotis is shown to range south through Phillips Co. in eastern Arkansas, and R. fulvescens is shown to range throughout most of the state, now including most of the Mississippi Alluvial Plain. A new specimen of R. humulis from Delaware Co., Oklahoma, suggests that this species probably ranges throughout northwestern Arkansas. R montanus remains known only from Washington Co. in northwestern Arkansas
Formation of o-Tyrosine and Dityrosine in Proteins during Radiolytic and Metal-catalyzed Oxidation
To evaluate their usefulness as chemical indicators of cumulative oxidative damage to proteins, we studied the kinetics and extent of formation of ortho-tyrosine (0-Tyr), dityrosine (DT), and dityrosine-like fluorescence (Ex = 3 17 nm, E,,, = 407 nm) in the model proteins RNase and lysozyme exposed to radiolytic and metalcatalyzed (H20z/Cu2+) oxidation (MCO). Although there were protein-dependent differences, o-Tyr, DT, and fluorescence increased coordinately during oxidation of the proteins in both oxidation systems. The contribution of DT to total dityrosine-like fluorescence in oxidized proteins varied from 2-10070, depending on the protein, type of oxidation, and extent of oxidative damage. In proteins exposed to MCO, DT typically accounted for \u3e50% of the fluorescence at DT wavelengths. These studies indicate that o-Tyr and DT should be useful chemical markers of cumulative exposure of proteins to MCO in vitro and in vivo
Oxidized Amino Acids in Lens Protein with Age: Measurement of o-Tyrosine and Dityrosine in the Aging Human Lens
The concentrations of ortho-tyrosine (o-Tyr) and dityrosine (DT) were measured in noncataractous human lenses in order to assess the role of proteinoxidation reactions in the aging of lens proteins. The measurements were conducted by selected ion monitoring-gas chromatography/mass spectrometry using deuterium-labeled internal standards, which provided both high sensitivity and specificity for the quantitation of o-Tyr and DT. Between ages 1 and 78 years, the o-Tyr concentration in lens proteins varied from 0.3 to 0.9 mmol of o-Tyr/mol of Phe (n = 19), while DT ranged from 1 to 3 mumol of DT/mol of Tyr (n = 30). There were no significant changes in levels of o-Tyr with lens age. There was a statistically significant, but only slight, increase in DT in lens proteins with age (approximately 33% increases between ages 1 and 78, r = 0.5, p \u3c 0.01). At the same time, totalprotein fluorescence, measured at DT wavelengths (Ex = 317 nm, Em = 407 nm), increased 11-fold between ages 1 and 78 and correlated strongly with age (r = 0.82, p \u3c 0.0001). Although the fluorescence maxima of lens proteins were similar to those of DT, DT accounted for less than 1% of the DT-like fluorescence in lens protein at all ages. These observations indicate that oxidation of Phe and Tyr plays a limited role in the normal aging of lens proteins in vivo
PITTSBURGHâS RACIAL DEMOGRAPHICS: DIFFERENCES AND DISPARITIES
Pittsburghâs Racial Demographics: Differences and Disparities provides indicators of quality of life by race and ethnicity in the Pittsburgh region. Data are provided for four groups (Whites, African Americans, Asians, and Hispanics) and for four geographic areas (city of Pittsburgh, Allegheny County, Pittsburgh Metropolitan Statistical Area, and the U.S.). The most recent data available for the Pittsburgh area and the nation were used in this report. In some instances, however, only data from the 2000 census were available to make comparisons. It is also the case that data were not available on all of our topic areas in the same years. It is our hope to update this report every three years, particularly if the American Community Survey (which is designed to replace the decennial census) produces regular, reliable data by race for cities, counties, and regions
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Separation of Diastereomers, Structural Isomers, and Homologs of n5 -Cyclopentadienyl Cobalt and Dinuclear Molybdenum Complexes by Reverse Phase High Performance Liquid Chromatography Using Deoxygenated Solvents
High Performance Liquid Chromatography (HPLC) is being used as an analytical and preparative tool for the characterization and isolation of a series of air-sensitive organometallic compounds, Reverse phase chranatography with octadecylsilyl-modified silica (ODS) as a stationary phase and polar mobile phases saturated with argon are employed in the separation of products
Personalisation in MOOCs: a critical literature review
The advent and rise of Massive Open Online Courses (MOOCs) have brought many issues to the area of educational technology. Researchers in the field have been addressing these issues such as pedagogical quality of MOOCs, high attrition rates, and sustainability of MOOCs. However, MOOCs personalisation has not been subject of the wide discussions around MOOCs. This paper presents a critical literature survey and analysis of the available literature on personalisation in MOOCs to identify the needs, the current states and efforts to personalise learning in MOOCs. The findings illustrate that there is a growing attention to personalisation to improve learnersâ individual learning experiences in MOOCs. In order to implement personalised services, personalised learning path, personalised assessment and feedback, personalised forum thread and recommendation service for related learning materials or learning tasks are commonly applied
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Relationship Between Climatic Factors and Distribution of Pratylenchus spp. in the Dryland Wheat-Production Areas of Eastern Washington
Field surveys were conducted by collecting soil samples to estimate
nematode densities in soil from winter wheat, spring wheat, spring
barley, and spring legumes (lentil, chickpea, and pea) fields during
2010 and 2011. Pratylenchus spp. were observed in 60% of sampled
fields. However, nematodes were detected in nearly all of the survey
fields in high numbers where crops were grown every year. To identify
climatic variables associated with density of Pratylenchus spp. in soil,
correlation and regression analyses were performed using climate data
of survey sites from 1979 to 2010. Fifty-seven climate variables were
significantly correlated with densities of Pratylenchus spp. All precipitation
variables were significantly positively correlated with nematode abundance. Summer maximum air temperature was negatively correlated
and winter minimum air temperature was positively correlated
with nematode densities. In addition, both yearsâ nematode densities
were significantly correlated with cropping intensity. Five multivariate
regression models for 2010 and seven models for 2011
nematode abundance levels were developed. The majority of the
climate variables selected in the models were related to precipitation.
Knowledge of root-lesion nematode distribution in the dryland
region of eastern Washington and associated climate variables may
be helpful to determine risk and apply management practices to
minimize crop damage
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