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Detection of DNA damage by space radiation in human fibroblasts flown on the International Space Station
No full textAlthough charged particles in space have been detected with radiation detectors on board spacecraft since the discovery of the Van Allen Belts, reports on the effects of direct exposure to space radiation in biological systems have been limited. Measurement of biological effects of space radiation is challenging due to the low dose and low dose rate nature of the radiation environment, and due to the difficulty in distinguishing the radiation effects from microgravity and other space environmental factors. In astronauts, only a few changes, such as increased chromosome aberrations in their lymphocytes and early onset of cataracts, are attributed primarily to their exposure to space radiation. In this study, cultured human fibroblasts were flown on the International Space Station (ISS). Cells were kept at 37 °C in space for 14 days before being fixed for analysis of DNA damage with the γ-H2AX assay. The 3-dimensional γ-H2AX foci were captured with a laser confocal microscope. Quantitative analysis revealed several foci that were larger and displayed a track pattern only in the Day 14 flight samples. To confirm that the foci data from the flight study was actually induced from space radiation exposure, cultured human fibroblasts were exposed to low dose rate γ rays at 37 °C. Cells exposed to chronic γ rays showed similar foci size distribution in comparison to the non-exposed controls. The cells were also exposed to low- and high-LET protons, and high-LET Fe ions on the ground. Our results suggest that in G1 human fibroblasts under the normal culture condition, only a small fraction of large size foci can be attributed to high-LET radiation in space
Combustion dynamics at the top dead center position of a spark ignition engine
No full textA zero-dimensional spark ignition engine model was used to conduct a systematic study of combustion dynamics at the top dead center (TDC) position of a 5.734 liter, V8 spark-ignition engine. The model captures all the experimentally observed essential features concerning combustion at the TDC. The combustion dynamics at compression ratios, rc = 9.5, 10.5, 11.5 and 15.5 and fuel-air equivalence ratio, θ = 1.0 were investigated with the numerical model. The results show that for rc = 15.5, the fueloxidizer charge was consumed almost instantaneously. Furthermore, the data shows that it took about 153.0, 52.6, 21.0 and 1.43 ms at compression ratios, rc of 9.5, 10.5, 11.5 and 15.5 respectively for the in-cylinder combustion dynamics to reach a value T* = 1.0. In the last 0.01 ms, for all compression ratios, the rate of change of pressure, dp/dt lies in the range 108 \u3c dp/dt \u3c 1014 Pa/s while the corresponding temperature varies from 2230 ≤ T ≤ 2700 K. The study also shows that as the compression ratio increases both the adiabatic flame temperature and heat of combustion at the top dead center increases monotonically as well
A study of the amputee experience of viewing self in the mirror
No full textPurpose: To describe the trajectory of viewing self in a mirror after an amputation and participants\u27 perceptions of what health care professionals should know about mirrors. Design: Hermeneutic phenomenology. Methods: Focus groups were conducted to collect the research data. Findings: The mirror experience had three key moments: decision, seeing, and consent. The trajectory of viewing self in a mirror had four key themes: mirror shock, mirror anguish, recognizing self, and acceptance: a new normal. Participants\u27 recommendations for introducing the mirror after an amputation and using a mirror to avoid skin breakdown and infection, and correct gait and balance are described. Conclusions: This study provides a unique viewpoint into the world of those who have suffered amputation of a limb. Clinical Relevance: Rehabilitation nurses and other health care professionals are encouraged through these participants to consider the effect and value of mirrors when caring for those who have had an amputation
Peace and Prosecution: An Analysis of Perceptions Towards the International Criminal Court Intervention’s in Northern Uganda
Get PDFThis paper evaluates the International Criminal Court’s impact in Northern Uganda through the lens of the affected community. It seeks a nuanced assessment of the Court by contextualizing the communities’ perceptions within their temporal context. Fluctuations in local perceptions of the Court in relation to developments on the ground identify peace as a local priority. The ICC must not simply behave in a static and rigid time-logic, but rather respond to shifting priorities and circumstances. It is this temporal consciousness that will make the ICC relevant both in context and in support
Explaining Political Trust among African Americans
Get PDFAfrican Americans have low levels of political trust when compared to white Americans. Explanations of African American’s political trust remain minimal. Utilizing data taken from the 1996 National Black Election Study and ordered probit to analyze the data, this study examines four explanations of African American political trust. It estimates political trust as a function of demographics, perceptions about the economy, beneficence from the government, and race orientation. Results show support for most of these factors, but no support for government beneficence. Social location, economic evaluations, and orientation to race influence African American political trust. I conclude that group-centric perceptions of African Americans’ conditions play an important role in explaining the race’s political trust
Identification of 12 new susceptibility loci for different histotypes of epithelial ovarian cancer
No full textTo identify common alleles associated with different histotypes of epithelial ovarian cancer (EOC), we pooled data from multiple genome-wide genotyping projects totaling 25,509 EOC cases and 40,941 controls. We identified nine new susceptibility loci for different EOC histotypes: six for serous EOC histotypes (3q28, 4q32.3, 8q21.11, 10q24.33, 18q11.2 and 22q12.1), two for mucinous EOC (3q22.3 and 9q31.1) and one for endometrioid EOC (5q12.3). We then performed meta-analysis on the results for high-grade serous ovarian cancer with the results from analysis of 31,448 BRCA1 and BRCA2 mutation carriers, including 3,887 mutation carriers with EOC. This identified three additional susceptibility loci at 2q13, 8q24.1 and 12q24.31. Integrated analyses of genes and regulatory biofeatures at each locus predicted candidate susceptibility genes, including OBFC1, a new candidate susceptibility gene for low-grade and borderline serous EOC
The Economic Impact of Changing Water Levels: A Regional Economic Analysis of Lake Thurmond
Get PDFThis article examines the economic impact of declining lake levels on the local economy in six counties near the publically managed Thurmond Reservoir, located along the border of Georgia and South Carolina. A regression analysis of the relationship between lake level elevations and lake front real estate transactions is used in conjunction with an input-output model to estimate the median monthly economic impact of a one-foot increase in lake level in terms of employment, output, disposable income, and net local government revenue on the six counties bordering the lake. Thurmond Lake elevations have a statistically significant impact on regional economic impact activity but the direction and magnitude depend on a variety of factors, including the size and diversity of each county’s economy and the proximity of the commercial centers within each county to the lake
The Logic of Uncertainty and Executive Discretion in Decision Making: The Dallas-Fort Worth Metroplex Ebola Response
Get PDFThis paper addresses an important question: what can a highly complex public health situation such as the Dallas-Fort Worth Ebola outbreak tell us about the use of discretion by executive level public administrators? The public administration literature is rich with evidence of street-level bureaucratic discretion, but has not explored executive level discretion decision making. The authors argue that in highly complex situations of uncertainty, such as in the case of the Dallas-Fort Worth regional Ebola emergency response, the executive use of discretion translates to decisions under the conditions of uncertainty. This article theorizes a logic of uncertainty when two important assumptions exist; the situation is absent a plan to guide decision making, and the decision makers lack any previous precedent with the situation. Results indicate that when survey respondents departed from their emergency management plan, and planned as the event folded, they were more likely to use executive discretion decision making
Multi-physical field guided wave simulation for circular concrete-filled steel tubes coupled with piezoelectric patches considering debonding defects
No full textThe active interface debonding detection for concrete-filled steel tubes (CFSTs) using Piezoelectric Lead Zirconate Titanate (PZT) patches has been proposed and experimentally studied in recent years. In order to further investigate the guided wave propagation and the response of embedded PZT sensor, transient dynamic analysis on multi-physical field coupling models composed of surface-mounted PZT actuator, embedded PZT sensor and a circular CFST specimen considering the coupling effect between the PZT patches and CFST member and the influence of interface debonding defects is carried out numerically. The guided wave propagation within the CFST-PZT coupling system without and with interfacial debonding defects under single period impulse signal is simulated and compared. The voltage response time history of the embedded PZT sensor in coupling models under both sinusoidal and sweep frequency sinusoidal excitations are simulated as an alternative solver. Numerical results demonstrate that interface debonding leads to changes in guided wave propagation path, traveling time and the PZT sensor response. The sensitivity of a quantitative evaluation index called as the normalized wavelet packet energy of the output voltage of embedded PZT sensor to the initiation of interface debonding defect and its length and depth is illustrated
Effect of arsenic acid withdrawal on hepatotoxicity and disruption of erythrocyte antioxidant defense system
No full textWe investigated the effects of withdrawal from Sodium arsenite (NaAsO2) on the hepatic and antioxidant defense system in male Wistar rats using a before and after toxicant design. Rats were orally gavaged daily with varying doses of NaAsO2 for a period of 4 weeks. One half of the population was sacrificed and the remaining half had the toxicant withdrawn for another further 4 weeks. Biochemical and immunohistochemical techniques were used to assess the impact of withdrawal on the erythrocyte and hepatic systems. Exposure of Wistar rats to NaASO2 led to a significant (p \u3c 0.05) increase in hepatic and erythrocyte markers of oxidative stress (malondialdehyde, thiol contents and hydrogen peroxide generation). Concurrently, there was a significant (p \u3c 0.05) increase in hepatic and erythrocyte antioxidant enzymes (glutathione-S-transferase, glutathione peroxidase and superoxide dismutase) following exposure. Withdrawal from NaAsO2 exposure led to a decline in both erythrocyte and hepatic markers of oxidative stress and together with a significant improvement in antioxidant defense system. Histopathology and immunohistochemistry revealed varying degrees of recovery in hepatocyte ultrastructure alongside increased expression of the pro-survival protein Kinase B (Akt/PKB) after 4 weeks of NaAsO2 withdrawal. Conclusively, withdrawal from exposure led to a partial recovery from oxidative stress-mediated hepatotoxicity and derangements in erythrocyte antioxidant system through Akt/PKB pathway