The Effects of Whole-Watershed Calcium Addition on Preferential Uptake of Calcium vs. Strontium and the Isotopic Ratio of 87Sr/86Sr into Foliage at the Hubbard Brook Experimental Forest, New Hampshire.

Calcium is an essential if not normally a limiting base cation nutrient in forest ecosystems. The increase in acid deposition (acid rain) in modern times has caused concern about long term leaching of the base cation exchange pool in soils, potentially causing serious damage across northern forests (Likens et al. 1996). Strontium, also an alkaline earth element, is present in trace amounts in rocks and soils. It is thought to be incorporated into plant tissues similarly to calcium because of its ionic size and charge (Ash-Dasch et al. 2006). Strontium forms four stable isotopes in nature 84Sr, 86Sr, 87Sr, and 88Sr (webelements.com). Of these isotopes of strontium, only 87Sr varies due to radioactive decay of naturally occurring 87Rb (Ash-Dasch et al. 2006). Because of this decay different terrestrial geochemical reservoirs develop unique ratios of 87Sr/86Sr over time. Because calcium and strontium are assumed to have similar geochemical behaviors, the ratio of calcium to strontium (Ca/Sr) and the ratio between the isotopes of 87Sr and 86Sr has commonly been used to trace the sources of calcium in forest ecosystems (Ash-Dasch 2006; Blum et a. 2000). Previous work in this field has established that the uptake rates of Ca and Sr vary between plant species (Ash-Dasch et al. 2006). Correctly interpreting Ca/Sr and 87Sr/86Sr data in order to trace calcium requires understanding the extent to which species discriminate between calcium and strontium during uptake. The discrimination factor (DF) between Ca and Sr can be estimated and applied to nutrient flow studies of calcium through different ecosystems. This study examines ten years of chemical data from several tree species in Ca-depleted forested watershed. Data came from a whole watershed calcium addition experiment in the Hubbard Brook Experimental-Forest, NH (Peters et al. 2004). The experiment was begun in October of 1999 and sample collection is ongoing. Results for data from 1999-2004 were published in Ash-Dash et al. 2006. Here, I will be updating the data set and calculating discrimination factors after including new data from 2004 through 2008. Following our calculations, a DF greater than 1 indicates a plant’s preference for calcium over strontium, and a DF less than one indicates a preference for strontium over calcium. Widespread calcium depletion has been documented across northeastern North America, including the watershed studied here. The depletion is due to increased acid deposition (Likens et a. 1998). The consequences of calcium depletion on northern forests are only partly understood. At the Hubbard Brook Experimental Forest unexpected declines in biomass accumulation have been observed since the late 1980’s, which may relate to increased acid deposition and subsequent leaching of calcium from the nutrient pool (Likens et al. 1996). While some research (focused on global sulfur and nitrogen cycles) on acid rain has indicated that the effects of acid rain on forest nutrient cycles would be limited, there is evidence that the effects of changes in calcium cation pools on forest health could be much stronger(Likens et al. 1996). Spruce (Picea spp.) trees are particularly vulnerable to calcium deficiencies in the form of increased freezing injuries in low Ca environments (DeHayes 1999). The vulnerability of forests to calcium depletion and the damage already done tothem by acid rain are reasons why being able to trace ecological sources of calcium could aid in long term forest preservation and help inform environmental policy. Adding calcium to an entire watershed (whole-watershed addition) allows for observations to be made about many aspects of calcium’s role in ecosystem health, and how this nutrient cycles through the ecosystem (Peters et a. 2004). The ratio of calcium to trace amounts strontium, and the isotopic ratio of 87Sr to86Sr in the source calcium added to the ecosystem can be used as a chemical marker to follow the added calcium as it flows through the ecosystem. In tracing that marker, observations can be made about relative uptake rates and absorption of calcium and strontium by various plant species. Because of divergent calcium chemistry between plants, characteristic preferences for calcium vs. strontium can then be applied to more reliably trace calcium sources over time in ecosystems.Honors (Bachelor's)LS&A: EnvironmentSNREUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/91039/1/Doman_Thesis.pd

A comparative study of traditional and inductive methods of teaching social studies

Call number: LD2668 .T4 1968 D64Master of Scienc

The effect of invasive earthworm Lumbricus terrestris on the distribution of nitrogen in soil profile

The purpose of this study was to determine if Lumbricus terrestris, an invasive earthworm in Northern Michigan, is redistributing nitrogen from the organic soil layer to the deeper, mineral soil layer. L. terrestris burrow 2 meters vertically into the ground and emerge to feed on freshly fallen leaf litter. The study included collecting of L. terrestris in 16 0.5 m square plots by method of electro-shock. Soil cores from a depth of 0-5 and 30-40 cm as well as leaf litter were taken from each plot to determine nitrogen content and nitrogen isotope ratios. Data analysis resulted in no significance between plots with earthworms and without earthworms in both nitrogen, N, isotope ratios and N content. Plots with L. terrestris showed no difference between the organic and mineral soil layer. This result suggests that L. terrestris are homogenizing soil layers. However, smaller than ideal sample sizes limit interpretive capacity of the results. Further research needs to be completed to confirm these perceived trends. The analysis of nitrogen isotope ratios suggest that there is another source of 15N other than leaf litter and L. terrestris that is contributing to soil composition and therefore the contribution of each was not conclusively determined.http://deepblue.lib.umich.edu/bitstream/2027.42/64579/1/Adelson_Doman_Golembiewski_Middleton_2009.pd

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Exploring nurses’ experiences of providing high dependency care in children’s wards

The care of critically ill children has received much attention in the past decade, and many of the recommendations from reports relating to the provision of paediatric intensive care have been addressed. In comparison, high dependency care has received less attention. This level of care is often provided on ‘general’ children’s wards, yet its impact on nursing staff and care delivery have received little attention. This article presents a study which explores nurses’ experiences of providing high dependency care on children’s wards using focus groups. Following analysis, six categories emerged: definitions and perceptions of high dependency care; having a high dependency unit; problems in district general hospitals; the skills needed for high dependency care; team working; and staffing for high dependency care. These findings have implications for current clinical, managerial and educational practice and for future developments in the field of high dependency care for children

Evaluation of epiandrosterone as a long‐term marker of testosterone use

Identification and evaluation of long-term markers is crucial in prolonging the detection window for anabolic steroid abuse in sport. Recently, sulfoconjugated epiandrosterone was identified as a potential long-term marker for the abuse of certain endogenous anabolic agents, including testosterone, which continues to be widely used as a performance enhancing agent in sport. To evaluate the applicability of epiandrosterone sulfate as a marker for testosterone use, administration studies were conducted with multiple modes of testosterone administration - transdermal, intramuscular, and subcutaneous. A modified sample preparation method was used to collect both glucuronidated and sulfoconjugated analytes of interest. Carbon isotope ratio measurements from the administration studies are presented here. Epiandrosterone was less effective than the conventionally used target compounds for detection of the low dose application (transdermal gel). With intramuscular administration, epiandrosterone was more diagnostic than with transdermal administration, but it did not prolong the detection window more than the conventional target compounds. With subcutaneous administration, the doses administered to the subjects were varied and the effect on the epiandrosterone values was dependent on the magnitude of the dose administered. Epiandrosterone does not appear to be a useful marker in the detection of low dose testosterone administration. It is responsive to higher dose administration, but it does not provide an extension of the detection window relative to conventional target compounds

Evaluation of epiandrosterone as a long-term marker of testosterone use

Identification and evaluation of long-term markers is crucial in prolonging the detection window for anabolic steroid abuse in sport. Recently, sulfoconjugated epiandrosterone was identified as a potential long-term marker for the abuse of certain endogenous anabolic agents, including testosterone, which continues to be widely used as a performance enhancing agent in sport. To evaluate the applicability of epiandrosterone sulfate as a marker for testosterone use, administration studies were conducted with multiple modes of testosterone administration - transdermal, intramuscular, and subcutaneous. A modified sample preparation method was used to collect both glucuronidated and sulfoconjugated analytes of interest. Carbon isotope ratio measurements from the administration studies are presented here. Epiandrosterone was less effective than the conventionally used target compounds for detection of the low dose application (transdermal gel). With intramuscular administration, epiandrosterone was more diagnostic than with transdermal administration, but it did not prolong the detection window more than the conventional target compounds. With subcutaneous administration, the doses administered to the subjects were varied and the effect on the epiandrosterone values was dependent on the magnitude of the dose administered. Epiandrosterone does not appear to be a useful marker in the detection of low dose testosterone administration. It is responsive to higher dose administration, but it does not provide an extension of the detection window relative to conventional target compounds