70 research outputs found
Effect of Dung Beetles on Dung Decomposition and Nuntrient Cycling in a Nebraska Rangeland
Management practice can have impacts on the abundance and frequency of dung beetle populations and nutrient cycling in grazing systems. Also, agriculture and livestock production land use is a considerable source of anthropogenic greenhouse gas (GHG) emissions, which are known to be one of the causes of global climate change. In this study, we evaluated the effect of dung beetle presence on the fluxes of greenhouse gasses (GHGâs) from dung pats in the semi-arid Sandhills region of Nebraska, by using closed chambers to measure the fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from dung pats that were exposed and unexposed to dung beetles. We also quantified the effects of dung beetle activity on the timing and magnitude of decomposition of dung, and subsequent fluxes of dung derived C and N into soil. We measured indicators of dung pat decomposition, dung pat C, N, and P variables, and soil C, N, and P variables below dung pats that were either exposed or unexposed to dung beetles. Higher fluxes of GHGâs from dung pats were observed. However, while higher fluxes of CO2 and N2O, and lower fluxes of CH4 due to dung pat exposure to dung beetles were observed, these effects were only significant in one experiment out of the four seasonal experiments performed. We also found that dung pat exposure to dung beetles can increase rates of mass loss in field moist dung pats, as well as rates of moisture loss. While higher concentrations of nutrients from dung pats in soil were observed, dung beetles had a minimal impact on the soil nutrient concentrations below decomposing dung pats. Environmental factors overall were much more impactful, and dung and soil nutrients, as well as GHG emissions, responded in accordance with temporal fluctuations in the environmental variables that were measured. Our study suggests that management considerations in regards to GHG emissions and nutrient cycling within subirrigated meadows of the Sandhills, might not need to offer as much concern to the effects of dung beetles as perhaps previously believed.
Advisor: Martha Mam
Effect of Dung Beetles on Dung Decomposition and Nuntrient Cycling in a Nebraska Rangeland
Management practice can have impacts on the abundance and frequency of dung beetle populations and nutrient cycling in grazing systems. Also, agriculture and livestock production land use is a considerable source of anthropogenic greenhouse gas (GHG) emissions, which are known to be one of the causes of global climate change. In this study, we evaluated the effect of dung beetle presence on the fluxes of greenhouse gasses (GHGâs) from dung pats in the semi-arid Sandhills region of Nebraska, by using closed chambers to measure the fluxes of carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from dung pats that were exposed and unexposed to dung beetles. We also quantified the effects of dung beetle activity on the timing and magnitude of decomposition of dung, and subsequent fluxes of dung derived C and N into soil. We measured indicators of dung pat decomposition, dung pat C, N, and P variables, and soil C, N, and P variables below dung pats that were either exposed or unexposed to dung beetles. Higher fluxes of GHGâs from dung pats were observed. However, while higher fluxes of CO2 and N2O, and lower fluxes of CH4 due to dung pat exposure to dung beetles were observed, these effects were only significant in one experiment out of the four seasonal experiments performed. We also found that dung pat exposure to dung beetles can increase rates of mass loss in field moist dung pats, as well as rates of moisture loss. While higher concentrations of nutrients from dung pats in soil were observed, dung beetles had a minimal impact on the soil nutrient concentrations below decomposing dung pats. Environmental factors overall were much more impactful, and dung and soil nutrients, as well as GHG emissions, responded in accordance with temporal fluctuations in the environmental variables that were measured. Our study suggests that management considerations in regards to GHG emissions and nutrient cycling within subirrigated meadows of the Sandhills, might not need to offer as much concern to the effects of dung beetles as perhaps previously believed.
Advisor: Martha Mam
What predicts oral health stability in a long-term care population?
The purpose of this study was to determine whether oral health stability was achievable over time for institutionalized elderly who routinely received comprehensive care and to examine the factors associated with stability. Records of 868 dentate nursing home residents, each with a minimum of 24 months continuous care, were analyzed to determine the number of services by type for each time period between periodic examinations. Presenting dental condition, age, gender, functional status, payer source and facility characteristics were tested as explanatory variables. Oral health status was considered stable when a resident had aâgood checkupâ (needing no further treatment), otherwise it was coded as unstable. Generalized estimating equations (GEE) were used to analyze predictors of stability over time. Stability over time was achieved in 44% of the study group and negatively associated with male gender, advanced age, and more initial treatment needs. The data show that high levels of initial unmet needs were associated with difficulty achieving oral health stability for institutionalized elderly who routinely received comprehensive care.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75086/1/j.1754-4505.2005.tb01426.x.pd
Oropharyngeal Candidosis in the Older Patient
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111172/1/j.1532-5415.1997.tb01517.x.pd
Nosocomial Pneumonia and Oral Health
This article will critically review the evidence linking pneumonia to the aspiration of microbe-laden oropharyngeal secretions and tie that to the predisposition for these processes to affect dependent, medically compromised individuals. The goal of this review is to alert the reader to the role that oral disease and oral health play in fostering and preventing, respectively, widespread and potentially fatal pulmonary disease among high-risk individuals.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73840/1/j.1754-4505.2005.tb01647.x.pd
Hypermethylation of the TGF-ÎČ target, ABCA1 is associated with poor prognosis in ovarian cancer patients
Background
The dysregulation of transforming growth factor-ÎČ (TGF-ÎČ) signaling plays a crucial role in ovarian carcinogenesis and in maintaining cancer stem cell properties. Classified as a member of the ATP-binding cassette (ABC) family, ABCA1 was previously identified by methylated DNA immunoprecipitation microarray (mDIP-Chip) to be methylated in ovarian cancer cell lines, A2780 and CP70. By microarray, it was also found to be upregulated in immortalized ovarian surface epithelial (IOSE) cells following TGF-ÎČ treatment. Thus, we hypothesized that ABCA1 may be involved in ovarian cancer and its initiation.
Results
We first compared the expression level of ABCA1 in IOSE cells and a panel of ovarian cancer cell lines and found that ABCA1 was expressed in HeyC2, SKOV3, MCP3, and MCP2 ovarian cancer cell lines but downregulated in A2780 and CP70 ovarian cancer cell lines. The reduced expression of ABCA1 in A2780 and CP70 cells was associated with promoter hypermethylation, as demonstrated by bisulfite pyro-sequencing. We also found that knockdown of ABCA1 increased the cholesterol level and promoted cell growth in vitro and in vivo. Further analysis of ABCA1 methylation in 76 ovarian cancer patient samples demonstrated that patients with higher ABCA1 methylation are associated with high stage (Pâ=â0.0131) and grade (Pâ=â0.0137). Kaplan-Meier analysis also found that patients with higher levels of methylation of ABCA1 have shorter overall survival (Pâ=â0.019). Furthermore, tissue microarray using 55 ovarian cancer patient samples revealed that patients with a lower level of ABCA1 expression are associated with shorter progress-free survival (Pâ=â0.038).
Conclusions
ABCA1 may be a tumor suppressor and is hypermethylated in a subset of ovarian cancer patients. Hypermethylation of ABCA1 is associated with poor prognosis in these patients
Genotype-Phenotype Correlation in NF1: Evidence for a More Severe Phenotype Associated with Missense Mutations Affecting NF1 Codons 844â848
Neurofibromatosis type 1 (NF1), a common genetic disorder with a birth incidence of 1:2,000â3,000, is characterized by a highly variable clinical presentation. To date, only two clinically relevant intragenic genotype-phenotype correlations have been reported for NF1 missense mutations affecting p.Arg1809 and a single amino acid deletion p.Met922del. Both variants predispose to a distinct mild NF1 phenotype with neither externally visible cutaneous/plexiform neurofibromas nor other tumors. Here, we report 162 individuals (129 unrelated probands and 33 affected relatives) heterozygous for a constitutional missense mutation affecting one of five neighboring NF1 codonsâLeu844, Cys845, Ala846, Leu847, and Gly848âlocated in the cysteine-serine-rich domain (CSRD). Collectively, these recurrent missense mutations affect âŒ0.8% of unrelated NF1 mutation-positive probands in the University of Alabama at Birmingham (UAB) cohort. Major superficial plexiform neurofibromas and symptomatic spinal neurofibromas were more prevalent in these individuals compared with classic NF1-affected cohorts (both p < 0.0001). Nearly half of the individuals had symptomatic or asymptomatic optic pathway gliomas and/or skeletal abnormalities. Additionally, variants in this region seem to confer a high predisposition to develop malignancies compared with the general NF1-affected population (p = 0.0061). Our results demonstrate that these NF1 missense mutations, although located outside the GAP-related domain, may be an important risk factor for a severe presentation. A genotype-phenotype correlation at the NF1 region 844â848 exists and will be valuable in the management and genetic counseling of a significant number of individuals
The Science Performance of JWST as Characterized in Commissioning
This paper characterizes the actual science performance of the James Webb
Space Telescope (JWST), as determined from the six month commissioning period.
We summarize the performance of the spacecraft, telescope, science instruments,
and ground system, with an emphasis on differences from pre-launch
expectations. Commissioning has made clear that JWST is fully capable of
achieving the discoveries for which it was built. Moreover, almost across the
board, the science performance of JWST is better than expected; in most cases,
JWST will go deeper faster than expected. The telescope and instrument suite
have demonstrated the sensitivity, stability, image quality, and spectral range
that are necessary to transform our understanding of the cosmos through
observations spanning from near-earth asteroids to the most distant galaxies.Comment: 5th version as accepted to PASP; 31 pages, 18 figures;
https://iopscience.iop.org/article/10.1088/1538-3873/acb29
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Effect of Hydrocortisone on Mortality and Organ Support in Patients With Severe COVID-19: The REMAP-CAP COVID-19 Corticosteroid Domain Randomized Clinical Trial.
Importance: Evidence regarding corticosteroid use for severe coronavirus disease 2019 (COVID-19) is limited. Objective: To determine whether hydrocortisone improves outcome for patients with severe COVID-19. Design, Setting, and Participants: An ongoing adaptive platform trial testing multiple interventions within multiple therapeutic domains, for example, antiviral agents, corticosteroids, or immunoglobulin. Between March 9 and June 17, 2020, 614 adult patients with suspected or confirmed COVID-19 were enrolled and randomized within at least 1 domain following admission to an intensive care unit (ICU) for respiratory or cardiovascular organ support at 121 sites in 8 countries. Of these, 403 were randomized to open-label interventions within the corticosteroid domain. The domain was halted after results from another trial were released. Follow-up ended August 12, 2020. Interventions: The corticosteroid domain randomized participants to a fixed 7-day course of intravenous hydrocortisone (50 mg or 100 mg every 6 hours) (nâ=â143), a shock-dependent course (50 mg every 6 hours when shock was clinically evident) (nâ=â152), or no hydrocortisone (nâ=â108). Main Outcomes and Measures: The primary end point was organ support-free days (days alive and free of ICU-based respiratory or cardiovascular support) within 21 days, where patients who died were assigned -1 day. The primary analysis was a bayesian cumulative logistic model that included all patients enrolled with severe COVID-19, adjusting for age, sex, site, region, time, assignment to interventions within other domains, and domain and intervention eligibility. Superiority was defined as the posterior probability of an odds ratio greater than 1 (threshold for trial conclusion of superiority >99%). Results: After excluding 19 participants who withdrew consent, there were 384 patients (mean age, 60 years; 29% female) randomized to the fixed-dose (nâ=â137), shock-dependent (nâ=â146), and no (nâ=â101) hydrocortisone groups; 379 (99%) completed the study and were included in the analysis. The mean age for the 3 groups ranged between 59.5 and 60.4 years; most patients were male (range, 70.6%-71.5%); mean body mass index ranged between 29.7 and 30.9; and patients receiving mechanical ventilation ranged between 50.0% and 63.5%. For the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively, the median organ support-free days were 0 (IQR, -1 to 15), 0 (IQR, -1 to 13), and 0 (-1 to 11) days (composed of 30%, 26%, and 33% mortality rates and 11.5, 9.5, and 6 median organ support-free days among survivors). The median adjusted odds ratio and bayesian probability of superiority were 1.43 (95% credible interval, 0.91-2.27) and 93% for fixed-dose hydrocortisone, respectively, and were 1.22 (95% credible interval, 0.76-1.94) and 80% for shock-dependent hydrocortisone compared with no hydrocortisone. Serious adverse events were reported in 4 (3%), 5 (3%), and 1 (1%) patients in the fixed-dose, shock-dependent, and no hydrocortisone groups, respectively. Conclusions and Relevance: Among patients with severe COVID-19, treatment with a 7-day fixed-dose course of hydrocortisone or shock-dependent dosing of hydrocortisone, compared with no hydrocortisone, resulted in 93% and 80% probabilities of superiority with regard to the odds of improvement in organ support-free days within 21 days. However, the trial was stopped early and no treatment strategy met prespecified criteria for statistical superiority, precluding definitive conclusions. Trial Registration: ClinicalTrials.gov Identifier: NCT02735707
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