The determination of gasoline and alkyl benzenes in aqueous solution and the development of a remote reaction chamber for fiber optic remote sensing

The development and optimization of a single-phase derivatization technique for small ring aromatics in water are presented. Also described are the design, optimization and application of a remote reaction chamber for fiber optic sensing. Aqueous solutions of the major aromatic compounds in gasoline are derivatized to o-nitrosophenol-Cu complexes with a modified Baudisch reaction. The rate of formation of the complex is spectrophotometrically monitored at 310 nm and related to the concentration of benzene and alkyl benzenes present. The measured rate for aqueous gasoline samples is then related to gasoline concentration by estimating the relative aromatic composition of the gasoline sample. The technique provides a detection limit (DL) of 4 x 10⁻⁵ % (v/v) and 4 x 10⁻⁴ % (v/v) for benzene and gasoline, respectively. The response is linear to 0.01% (v/v) for benzene and 0.005% (v/v) for gasoline. The technique was successfully applied as a bench top method for detecting gasoline and alkyl benzenes, but due to the loss in reactivity of the reagents once mixed, the methodology was not suited for remote sensing applications. A remote reaction chamber (RRC) optrode was developed to facilitate in situ monitoring using derivatization techniques to form a luminescent product. The RRC optrode is a submergible chamber into which excitation radiation is input with one optical fiber and emission radiation is collected and directed to a photodetection system with another optical fiber. The RRC optrode allows for the isolation of a sample by applying a vacuum to a one-way exhaust valve. When the vacuum is applied the sample enters through a one-way intake valve and partially fills the internal chamber. After the vacuum is terminated, up to three reagents are injected with automated syringes through injection lines. Mixing of the sample and injected reagents is accomplished with a miniature stir driver and stir bar contained in the RRC optrode. The formation of a luminescent species results, and the intensity of the emitted radiation is related to the concentration of the analyte being studied. The RRC optrode was developed and optimized for the determination of trace levels of Al(III) and Cr(VI). A modified method of standard addition was also developed for use with the RRC optrode and optimized for the Al(III) study. Trace levels of aluminum are determined by measuring the rate of formation of the fluorescent chelate of Al(III) with 2,4,2'-trihydroxy-azobenzene-5'-sulfonic acid. This method provides a DL of 0.13 ng/mL and a linear dynamic range of four orders of magnitude using the RRC optrode. One of the reagent lines of the RRC optrode was configured to inject an Al(III) standard solution to implement in situ standard addition measurements. Analysis of a tap water sample with external standards and the standard-addition procedure produced equivalent results. Low concentrations of Cr(VI) in water were determined by monitoring the intensity of the chemiluminescence (CL) produced when Cr(VI) is mixed with a lophine-H₂0₂-K0H reagent system in the RRC optrode. This technique exhibits a DL of 11 ng/mL with a linear response up to 10 μg/mL

The aurora kinase AIR-2 functions in the release of chromosome cohesion in Caenorhabditis elegans meiosis

Accurate chromosome segregation during cell division requires not only the establishment, but also the precise, regulated release of chromosome cohesion. Chromosome dynamics during meiosis are more complicated, because homologues separate at anaphase I whereas sister chromatids remain attached until anaphase II. How the selective release of chromosome cohesion is regulated during meiosis remains unclear. We show that the aurora-B kinase AIR-2 regulates the selective release of chromosome cohesion during Caenorhabditis elegans meiosis. AIR-2 localizes to subchromosomal regions corresponding to last points of contact between homologues in metaphase I and between sister chromatids in metaphase II. Depletion of AIR-2 by RNA interference (RNAi) prevents chromosome separation at both anaphases, with concomitant prevention of meiotic cohesin REC-8 release from meiotic chromosomes. We show that AIR-2 phosphorylates REC-8 at a major amino acid in vitro. Interestingly, depletion of two PP1 phosphatases, CeGLC-7α and CeGLC-7β, abolishes the restricted localization pattern of AIR-2. In Ceglc-7α/β(RNAi) embryos, AIR-2 is detected on the entire bivalent. Concurrently, chromosomal REC-8 is dramatically reduced and sister chromatids are separated precociously at anaphase I in Ceglc-7α/β(RNAi) embryos. We propose that AIR-2 promotes the release of chromosome cohesion via phosphorylation of REC-8 at specific chromosomal locations and that CeGLC-7α/β, directly or indirectly, antagonize AIR-2 activity

Greenhouse gas emissions in Sub-Saharan Africa

Current and future carbon emissions from land-use change and energy consumption were analyzed for Sub-Saharan Africa. The energy sector analysis was based on UN energy data tapes while the land-use analysis was based on a spatially-explicit land-use model developed specifically for this project. The impacts of different energy and land-use strategies on future carbon emissions were considered. (A review of anthropogenic emissions of methane, nitrous oxides, and chlorofluorocarbons in Sub-Saharan Africa indicated that they were probably minor in both a global and a regional context. The study therefore was focused on emissions of carbon dioxide.) The land-use model predicts carbon emissions from land use change and the amount of carbon stored in vegetation (carbon inventory) on a yearly basis between 1985 and 2001. Emissions and inventory are modeled at 9000 regularly-spaced point locations in Sub-Saharan Africa using location-specific information on vegetation type, soils, climate and deforestation. Vegetation, soils, and climate information were derived from continental-scale maps while relative deforestation rates(% of forest land lost each year) were developed from country-specific forest and deforestation statistics (FAO Tropical Forest Resources Assessment for Africa, 1980). The carbon emissions under different land use strategies in Sub-Saharan Africa were analyzed by modifying deforestation rates and altering the amount of carbon stored under different land uses. The considered strategies were: preservation of existing forests, implementation of agroforestry, and establishment of industrial tree plantations. 82 refs., 16 figs., 25 tabs

Performance/outcomes data and physician process challenges for practical big data efforts in radiation oncology

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146290/1/mp13136.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146290/2/mp13136_am.pd

Impacts of Surgery on Symptom Burden and Quality of Life in Pituitary Tumor Patients in the Subacute Post-operative Period

Background: Pituitary tumors are rare but are associated with significant symptoms that impact patients' quality of life (QOL). Surgery remains one of the most effective treatment options for long term disease control and symptom benefit, but symptom, and quality of life recovery in the subacute period has not been previously reported. This study aimed to better understand the impact of surgery on patients' symptom burden and QOL in the subacute post-surgical period.Methods: Twenty-three adult patients with pituitary tumors undergoing surgical resection at University of North Carolina Cancer Hospital were enrolled in this study. M.D. Anderson Symptom Inventory Brain Tumor Module, European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-BN20 questionnaires were collected pre- and 1-month post- surgical resection and differences were analyzed for individual and groups of symptoms and QOL using Wilcoxon signed-rank tests.Results: Twenty adult patients had both pre-operation and post-operation follow-up visits; 60% had functional pituitary adenomas. Seven symptoms including fatigue, memory, vision, numbness, speaking, appearance, and weakness were significantly improved at the 1-month post-operation visit while one symptom, sleep, worsened. Global Health Status/QOL measurements was improved minimally from 63 (SD 25) at pre-operation to 67 (SD 22) at 1-month post-operation without statistical significance.Conclusions: This study demonstrated a rapid improvement of many symptoms in the subacute post-operative period in pituitary tumor patients. Disturbed sleep was identified as the only symptom to worsen post-operatively, encouraging potential prospective interventions to improve sleep, and subsequently improve the QOL in pituitary tumor patients following surgical intervention

Changing Epidemiology of Serious Bacterial Infections in Febrile Infants without Localizing Signs

Objective: Historically, management of infants with fever without localizing signs (FWLS) has generated much controversy, with attempts to risk stratify based on several criteria. Advances in medical practice may have altered the epidemiology of serious bacterial infections (SBIs) in this population. We conducted this study to test the hypothesis that the rate of SBIs in this patient population has changed over time. Patients and Methods: We performed a retrospective review of all infants meeting FWLS criteria at our institution from 1997–2006. We examined all clinical and outcome data and performed statistical analysis of SBI rates and ampicillin resistance rates. Results: 668 infants met criteria for FWLS. The overall rate of SBIs was 10.8%, with a significant increase from 2002–2006 (52/ 361, 14.4%) compared to 1997–2001 (20/307, 6.5%) (p = 0.001). This increase was driven by an increase in E. coli urinary tract infections (UTI), particularly in older infants (31–90 days). Conclusions: We observed a significant increase in E. coli UTI among FWLS infants with high rates of ampicillin resistance. The reasons are likely to be multifactorial, but the results themselves emphasize the need to examine urine in all febrile infants,90days and consider local resistance patterns when choosing empiric antibiotics

Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians